Reducing the Diameter of Freight Vehicle Wheels – The Suitability of Q/D as a Control for Wheel-Rail Contact Stress

High wheel-rail contact stress is related to rail damage mechanisms such as gross plastic flow. Such high contact stresses are often generated by freight vehicles which have comparatively high axleloads. On railways in Great Britain (GB) a limit is placed on the ratio of static wheel load (Q) to wheel diameter (D) as a proxy to control contact stress related damage. However, there is increasing interest in the use of smaller diameter wheels on freight vehicles, in order to prolong wheelset life (smaller scrap diameter) and increase capacity within the GB’s constrained structure gauge. GB Railway Group Standards [1] limit Q/D to 0.13 kN/mm. However it is known that a number of freight wagons already operate above this limit, either due to derogations granted against the standard, or as a result of being introduced prior to the standard’s universal application (‘Grandfather Rights’). At least one vehicle type is known to operate with a Q/D ratio of up to 0.165 kN/mm. This paper presents the results of an investigation into the contact stress state of the GB network. This formed part of a larger study [2] undertaken with a view to allowing a reduction in wheel diameters for freight vehicles. The research was conducted as part of the industry’s R&D programme managed by the Rail Safety and Standards Board (RSSB)

Revoltierendes Anerkennen des Alter(n)s. Für eine unzeitgemäße Sicht auf das Alter

Das vielfach propagierte und gesellschaftlich positiv besetzte Bild des "aktiven Alterns" wird in diesem Beitrag kritisch betrachtet. Es wird die Frage aufgeworfen, inwiefern sich die Erwachsenenbildung mit ihrem Einsatz für ein aktives Altern in die Logiken einer neuen Sozialpolitik der Aktivierung verstrickt. Die Kritik aufgreifend, dass es mit den aktuell im Trend liegenden positiven Alterszuschreibungen zu einem Ausschluss von leidvollen Aspekten des Alterns kommt, wird aus einer bildungstheoretischen Perspektive für die Thematisierung von Körperlichkeit und die Anerkennung der Ambiguität menschlicher Existenz appelliert. "Revoltierendes Anerkennen des Alter(n)s" bietet der Erwachsenenbildung eine Sichtweise, die nicht zwischen Aktivität und Passivität polarisiert, sondern der Mehrdeutigkeit des Menschseins Rechnung trägt und damit auch einer möglichen ökonomischen und politischen Indienstnahme entgegentritt. (DIPF/Orig.)This article critically examines the idea of “active ageing” frequently propagated and positively seen by society. The question is raised to what extent adult education with its commitment to active ageing is caught up in the logic of a new social policy of activation. Responding to criticism that the current trend of attaching positive attributes to ageing leads to an exclusion of the painful aspects of ageing, the article employs an educational theory perspective to thematise physicality and to acknowledge the ambiguity of human existence. The “revolutionising acknowledgement of ageing and old age” provides adult education with a perspective that instead of polarising between activity and passivity accommodates the ambiguity of being human and thus takes steps against any possible economic and political exploitation. (DIPF/Orig.

Controllable Topic-Focused Abstractive Summarization

Controlled abstractive summarization focuses on producing condensed versions of a source article to cover specific aspects by shifting the distribution of generated text towards a desired style, e.g., a set of topics. Subsequently, the resulting summaries may be tailored to user-defined requirements. This paper presents a new Transformer-based architecture capable of producing topic-focused summaries. The architecture modifies the cross-attention mechanism of the Transformer to bring topic-focus control to the generation process while not adding any further parameters to the model. We show that our model sets a new state of the art on the NEWTS dataset in terms of topic-focused abstractive summarization as well as a topic-prevalence score. Moreover, we show via extensive experiments that our proposed topical cross-attention mechanism can be plugged into various Transformer models, such as BART and T5, improving their performance on the CNN/Dailymail and XSum benchmark datasets for abstractive summarization. This is achieved via fine-tuning, without requiring training from scratch. Finally, we show through human evaluation that our model generates more faithful summaries outperforming the state-of-the-art Frost model

Nucleation and growth of GaN nanorods on Si (111) surfaces by plasma-assisted molecular beam epitaxy - The influence of Si- and Mg-doping

The self-assembled growth of GaN nanorods on Si (111) substrates by plasma-assisted molecular beam epitaxy under nitrogen-rich conditions is investigated. An amorphous silicon nitride layer is formed in the initial stage of growth that prevents the formation of a GaN wetting layer. The nucleation time was found to be strongly influenced by the substrate temperature and was more than 30 min for the applied growth conditions. The observed tapering and reduced length of silicon-doped nanorods is explained by enhanced nucleation on nonpolar facets and proves Ga-adatom diffusion on nanorod sidewalls as one contribution to the axial growth. The presence of Mg leads to an increased radial growth rate with a simultaneous decrease of the nanorod length and reduces the nucleation time for high Mg concentrations

Electron injection-induced effects in Mn-doped GaN

Electron injection into Mn-doped GaN resulted in pronounced changes in the minority carrier diffusion length and cathodoluminescence. In particular, multiple-fold decrease of the band-to-band cathodoluminescence intensity was observed in the temperature between -50 and 80degreesC. This decrease was accompanied by an increase of the minority carrier diffusion length in the material, measured by electron-beam-induced current. Temperature-dependent cathodoluminescence measurements revealed a recovery of the cathodoluminescence intensity with an activation energy of 360 meV

Self-care and self-medication as central components of healthcare in Germany – on the way to evidence-based pharmacy

In Germany, self-care is, above all interpreted as the prevention and treatment of minor injuries and illnesses by the patients themselves – that is, without a physician's prescription or medical advice. Maintaining one's health in the sense of a preventive approach through non-medicinal measures also plays an important role. Self-medication in this context is the treatment with approved over-the-counter-(OTC)-medications. In addition, other OTC-products such as dietary supplements as well as complementary and alternative medicines including homeopathic medications are frequently requested options by pharmacy customers. OTC-medications are central components of the German healthcare system, with expert advice from pharmacists in community pharmacies (CP) enabling safe and effective treatment. Additionally, screening for appropriate self-medication by pharmacists ensures that serious illnesses receive timely medical attention. In addition to prescribed medication, self-medication is an important part of the CP business in Germany. In contrast to prescription products, the price of OTC-products is not regulated. As a consequence, the price of OTC-products (including also pharmacy-only drugs) is influenced by competition among CPs and mail-order pharmacies, respectively. The sales of OTC-products for self-medication outside pharmacies, e.g. in drugstores and supermarkets, is restricted to a limited number of specific products. Evidence-based counseling in CPs, while generally advocated still remains a challenge. The evidence for the usage of OTC-products from clinical studies is not yet optimally integrated into everyday pharmacy practice. Information tools such as EVInews offering regular newsletters and a database have been developed to reduce the evidence-to-practice gap and to improve the overall counseling quality. Furthermore, the switching of drugs from prescription-only to pharmacy-only status also challenge CPs to provide adequate and updated guidance

Patients’ handling of a standardized medication plan: a pilot study and method development

Purpose: The Action Plan for Medication Safety by the German Federal Ministry of Health introduced a standardized medication plan (MP), a printable document for the patient. The practical handling needs to be tested before the nationwide implementation in Germany. Therefore, the aims of our study were 1) to develop an instrument to evaluate the usage of the standardized MP, 2) to assess if patients can locate, and 3) understand important information. Moreover, we explored patients’ opinion and suggestions regarding the standardized MP template. Patients and methods: We conducted a cross-sectional study to evaluate the practical handling of the standardized MP. We interviewed 40 adult patients in seven community pharmacies in Germany, who took at least five medicines regularly and gave their written informed consent. The interview consisted of questions regarding finding and understanding information provided on a mock-up MP, patients’ opinion and the execution of the information on the MP by filling pill boxes. We eventually developed a new evaluation method to quantify the practical handling of the MP by rating the pill boxes filled by the patients. Results: Overall, the participants rated the MP positively. Thirty-nine (98%) participants found important information on a mock-up standardized MP. Patients were questioned to identify if they understood information on medical intake as it relates to meals. In particular, they were questioned about medicine intake “1 hour before a meal”, which 98% (n=39) interpreted correctly, and “during a meal”, which 100% (n=40) interpreted correctly. The less precise advice of “before a meal” was interpreted correctly by 73% (n=29), and only 15% (n=6) correctly interpreted the term “after the meal”. The evaluation of the filled pill boxes resulted in the “Evaluation Tool to test the handling of the Medication Plan” (ET-MP) – a weighted scoring system. Conclusion: The standardized MP is clearly arranged, and patients are able to find important information. The findings of this study resulted in minor but important revisions of the standardized MP template. The developed evaluation tool ET-MP may serve as an objective instrument to assess patients’ ability to transfer written information on the MP into practical handling of medicines

UV Photosensing Characteristics of Nanowire-Based GaN/AlN Superlattices

We have characterized the photodetection capabilities of single GaN nanowires incorporating 20 periods of AlN/GaN:Ge axial heterostructures enveloped in an AlN shell. Transmission electron microscopy confirms the absence of an additional GaN shell around the heterostructures. In the absence of a surface conduction channel, the incorporation of the heterostructure leads to a decrease of the dark current and an increase of the photosensitivity. A significant dispersion in the magnitude of dark currents for different single nanowires is attributed to the coalescence of nanowires with displaced nanodisks, reducing the effective length of the heterostructure. A larger number of active nanodisks and AlN barriers in the current path results in lower dark current and higher photosensitivity, and improves the sensitivity of the nanowire to variations in the illumination intensity (improved linearity). Additionally, we observe a persistence of the photocurrent, which is attributed to a change of the resistance of the overall structure, particularly the GaN stem and cap sections. In consequence, the time response is rather independent of the dark current.Comment: This document is the unedited Author's version of a Submitted Work that was subsequently accepted for publication in Nano Letters (2016), copyright (C) American Chemical Society after peer review. To access the final edited and published work see http://dx.doi.org/10.1021/acs.nanolett.6b0080

Suppression of the quantum-confined Stark effect in polar nitride heterostructures

Recently, we suggested an unconventional approach (the so-called Internal-Field-Guarded-Active-Region Design “IFGARD”) for the elimination of the quantum-confined Stark effect in polar semiconductor heterostructures. The IFGARD-based suppression of the Stark redshift on the order of electronvolt and spatial charge carrier separation is independent of the specific polar semiconductor material or the related growth procedures. In this work, we demonstrate by means of micro-photoluminescence techniques the successful tuning as well as the elimination of the quantum-confined Stark effect in strongly polar [000-1] wurtzite GaN/AlN nanodiscs as evidenced by a reduction of the exciton lifetimes by up to four orders of magnitude. Furthermore, the tapered geometry of the utilized nanowires (which embed the investigated IFGARD nanodiscs) facilitates the experimental differentiation between quantum confinement and Stark emission energy shifts. Due to the IFGARD, both effects become independently adaptable.DFG, 43659573, SFB 787: Halbleiter - Nanophotonik: Materialien, Modelle, Bauelement

Bandgap engineering in a nanowire: self-assembled 0, 1 and 2D quantum structures

Inherent to the nanowire morphology is the exciting possibility of fabricating materials organized at the nanoscale in three dimensions. Composition and structure can be varied along and across the nanowire, as well as within coaxial shells. This opens up a manifold of possibilities in nanoscale materials science and engineering which is only possible with a nanowire as a starting structure. As the variation in composition and structure is accompanied by a change in the band structure, it is possible to confine carriers within the nanowire. Interestingly, this results in the formation of local two, one and zero-dimensional structures from an electronic point of view within the nanowire. This novel palette of nanostructures paves the way toward novel applications in many engineering domains such as lasers, high-mobility transistors, quantum information and energy harvesting. In the present review we summarize and give an overview on recent achievements in the design and growth of advanced quantum structures starting from nanowire templates. The quantum structures presented have been grown by molecular beam epitaxy and correspond to different confinement approaches: quantum wells (2D), quantum wires (1D) and quantum dots (0D)