Colloquium: Atomic spin chains on surfaces

In the present Colloquium, we focus on the properties of 1-D magnetic systems on solid surfaces. From the emulation of 1-D quantum phases to the potential realization of Majorana edge states, spin chains are unique systems to study. The advent of scanning tunnelling microscope (STM) based techniques has permitted us to engineer spin chains in an atom-by-atom fashion via atom manipulation and to access their spin states on the ultimate atomic scale. Here, we present the current state of research on spin correlations and dynamics of atomic spin chains as studied by the STM. After a brief review of the main properties of spin chains on solid surfaces, we classify spin chains according to the coupling of their magnetic moments with the holding substrate. This classification scheme takes into account that the nature and lifetimes of the spin-chain excitation intrinsically depend on the holding substrate. We first show the interest of using insulating layers on metals, which generally results in an increase in the spin state's lifetimes such that their quantized nature gets evident and they are individually accessible. Next, we show that the use of semiconductor substrates promises additional control through the tunable electron density via doping. When the coupling to the substrate is increased for spin chains on metals, the substrate conduction electron mediated interactions can lead to emergent exotic phases of the coupled spin chain-substrate conduction electron system. A particularly interesting example is furnished by superconductors. Magnetic impurities induce states in the superconducting gap. Due to the extended nature of the spin chain, the in-gap states develop into bands that can lead to the emergence of 1-D topological superconductivity and, consequently to the appearance of Majorana edge states

CR TKA UHMWPE Wear Tested after Artificial Aging of the Vitamin E Treated Gliding Component by Simulating Daily Patient Activities

The wear behaviour of total knee arthroplasty (TKA) is dominated by two wear mechanisms: the abrasive wear and the delamination of the gliding components, where the second is strongly linked to aging processes and stress concentration in the material. The addition of vitamin E to the bulk material is a potential way to reduce the aging processes. This study evaluates the wear behaviour and delamination susceptibility of the gliding components of a vitamin E blended, ultra-high molecular weight polyethylene (UHMWPE) cruciate retaining (CR) total knee arthroplasty. Daily activities such as level walking, ascending and descending stairs, bending of the knee, and sitting and rising from a chair were simulated with a data set received from an instrumented knee prosthesis. After 5 million test cycles no structural failure of the gliding components was observed. The wear rate was with mg/million cycles falling within the limit of previous reports for established wear test methods

Fundamente leistungsbezogener Arbeitsorganisation: implizites Regelwissen im Organisationsvergleich

Der Aufsatz vergleicht Kontextbedingungen von Arbeit in Organisationen verschiedenen Typs. Anhand einer explorativen, qualitativen Vergleichsstudie wird der Frage nachgegangen, ob sich im Zuge vergleichbarer Rationalisierungsstrategien vergleichbare Arbeitsweisen in einer Verwaltung und in einem Unternehmen ergeben haben. Dies soll am Beispiel impliziten Regelwissens, das sind Hintergrunderwartungen und Voraussetzungen der Geltung von Regeln, exploriert werden. Anlass dieser Fragestellung sind ähnliche organisationale Regeländerungen, die im Zuge von Neuer Leistungssteuerung und New Public Management flächendeckend in Organisationsstrukturen implementiert wurden. Die These lautet, dass organisationstypenspezifische Strukturbedingungen unterschiedliche Wechselwirkungen zwischen expliziten Regeln und implizitem Regelwissen bedingen. Verwaltungen und Unternehmen haben sich daher in der Folge dieser Reformwelle kaum angeglichen.The article compares terms of context of work, using the example of performance-related rules in organizations of different types. On the basis of an explorative, qualitative comparative study the question is followed, whether and to what extent the use of comparable rationalization strategies led to comparable ways of working in an administration and a business corporation. This question will be explored on the subject of implicit rule-related knowledge (preconditions of the validity of rules). Reasons for this kind of question are changes of organizational rules that took place extensively in the course of reforms like New Public Management and the implementation of new performance management systems. The assumption is that organizational-type structures determine different kinds of implicit rule-related knowledge. Therefore administrations and business organizations did not align themselves as a consequence of the reform-wave

Nye spor efter 700 års industrihistorie i Støvring

I begyndelsen af 2021 stødte arkæologer fra Nordjyske Museer på et stykke spændende lokalhistorie. I forbindelse med etableringen af et nyt regnvandsbassin i Støvring by fandt de flere stadier af den gamle Støvring Vandmølle – en mølle, der første gang nævnes i et testamente fra 1268, og derefter kan følges helt frem til 1958, hvor driften ophørte. En industrihistorie, som ved den arkæologiske udgravning i 2021 atter kom frem i lyset, og hvor det viste sig, at møllen blev opført så tidligt som i 1250

Potential of process information transfer along the process chain of hybrid components for process monitoring of the cutting process

The production of hybrid components involves a long process chain, which leads to high investment costs even before machining. To increase process safety and process quality during finishing, it is necessary to provide information about the semi-finished parts geometry for the machining process and to identify defect components at an early stage. This paper presents an investigation to predict variations in dimension and cavities inside the material during cross-wedge rolling of shafts based on measured tool pressure. First, the process is investigated with respect to the variation in diameter for three roll gaps and two materials. Subsequently, features are generated from the hydraulic pressures of the tools and multi-linear regression models are developed in order to determine the resulting diameters of the shaft shoulder. These models show better prediction accuracy than models based on meta-data about set roll gap and formed material. The features are additionally used to successfully monitor the process with regard to the Mannesmann effect. Finally, a sensor concept for a new cross-wedge rolling machine to improve the prediction of the workpiece geometry and a new approach for monitoring machining processes of workpieces with dimensional variations are presented for upcoming studies

Diabetes and ischemic heart disease:double jeopardy with regard to depressive mood and reduced quality of life

The aim of this study was to test i) whether patients having diabetes and ischemic heart disease (IHD), i.e., patients suffering from two chronic diseases, demonstrate a higher degree of chronic stress when compared with patients suffering from IHD alone, and ii) whether suffering from the two chronic diseases results in an elevation in specific elements of the chronic stress concept. A total of 361 participants with IHD were included, of whom 47 suffered from concomitant diabetes. Stress was measured by pressure pain sensitivity (PPS) and by the following questionnaires: the Major Depression Inventory (MDI), the SF-36 Quality of Life questionnaire (SF-36 QOL), the WHO-5 Well-being Index, and the clinical stress signs (CSSs) scale. Participants with diabetes and IHD had a higher MDI score, a lower SF-36 physical component summary score, and a lower score of several sub-measurements of the SF-36 mental component score when compared with patients with IHD without diabetes. No significant differences were observed regarding stress measured by the PPS measure, the WHO-5 Well-being Index, or the number of CSSs. In conclusion, the combination of diabetes and IHD seems to be associated with increased depressive symptoms, lower overall physical QOL, and reduced mental QOL on several sub-elements of the questionnaire. This should be recognized in the management of patients with double diagnoses