894 research outputs found

    Multiphysics Simulation of a Battery Electric Train Operation

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    The changeover from diesel driven multiple units to battery electric multiple units is a challenge for operators due to the limited range of these trains. Therefore, in this paper a tool is developed and described that simulates the entire operation of a battery electric train. The tool contains a model of the track, the vehicle, the timetable and the environment. The model of the track is built on elevation profiles, radius information and speed limitation. The vehicle model is derived from an electric multiple unit suitable for local and commuter train operation. To do parametric studies or model different train units it is easily possible to change vehicle properties. Modeling the timetable and the environment allows the simulation of an entire operation day. The overall simulation model was validated and is consistent. Finally examples show the simulation possibilities and features of the tool

    Sensorkonzept zur direkten Bestimmung von Zustandsgrößen an aktiv gelenkten Fahrwerken für Straßenbahnen

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    Mechatronische Fahrwerke mit aktiver Spurführung können Verschleiß und Lärm im Vergleich zu konventionellen Fahrwerken durch Vermeidung des Spurkranzanlaufs reduzieren. Trotz wissenschaftlicher Untersuchungen, die das Potential aufzeigen, wird eine technische Umsetzung selten vorgenommen. Dies liegt unter anderem an unzureichender Verfügbarkeit von geeigneter Messtechnik, insbesondere von Sensoren. Zur Regelung des Spurführungsverhaltens benötigen mechatronische Fahrwerke Kenntnisse über ihren aktuellen Zustand. Am Markt erhältliche Sensoren sind oft ungeeignet, wichtige Zustandsgrößen am Fahrwerk während der Fahrt direkt zu messen. Alternative Ansätze, die interessierenden Größen über Zustandsschätzer ableiten, sind oft unzureichend genau. In dieser Arbeit wird anhand eines aktiv gelenkten Radpaars ein neues Sensorkonzept zur direkten Bestimmung der Zustandsgrößen Anlaufwinkel und Lateralversatz vorgestellt. Aus den Anforderungen mechatronischer Fahrwerke wird mittels des V-Modells in drei Makrozyklen ein Sensorkonzept entwickelt und prototypisch aufgebaut. Das Sensorkonzept nutzt dabei die ferromagnetischen Eigenschaften der Schiene. Ein durch den Sensor künstlich erzeugtes Magnetfeld wird durch die Schiene verändert, und Hallsensorelemente messen diese Veränderungen. Aus den Messdaten wird die Lateralposition der Schiene unter dem Sensor über einen Luftspalt von 20mm mit ausreichender Genauigkeit berechnet. Der Sensorprototyp wird mittels einer Simulation des aktiv gelenkten Radpaars in verschiedenen Testszenarien validiert. Mit zusätzlichen Hardware-in-the-loop-Versuchen wird gezeigt, dass das Sensorkonzept für die mechatronische Spurführung eignet ist

    A Two-Step Machine Learning Method for Predicting the Formation Energy of Ternary Compounds

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    Predicting the chemical stability of yet-to-be-discovered materials is an important aspect of the discovery and development of virtual materials. The conventional approach for computing the enthalpy of formation based on ab initio methods is time consuming and computationally demanding. In this regard, alternative machine learning approaches are proposed to predict the formation energies of different classes of materials with decent accuracy. In this paper, one such machine learning approach, a novel two-step method that predicts the formation energy of ternary compounds, is presented. In the first step, with a classifier, we determine the accuracy of heuristically calculated formation energies in order to increase the size of the training dataset for the second step. The second step is a regression model that predicts the formation energy of the ternary compounds. The first step leads to at least a 100% increase in the size of the dataset with respect to the data available in the Materials Project database. The results from the regression model match those from the existing state-of-the-art prediction models. In addition, we propose a slightly modified version of the Adam optimizer, namely centered Adam, and report the results from testing the centered Adam optimizer.Deutsche ForschungsgemeinschaftPeer Reviewe

    Dispositivo de lectura de microarrays de tipo eléctrico y reutilizable

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    Dispositivo de lectura de microarrays de tipo eléctrico y reutilizable. El objeto principal de la presente invención es un dispositivo de lectura eléctrica de microarrays que se puede limpiar y volver a utilizar más de una vez. El dispositivo (1, 1’, 1”) de lectura de microarrays (6) tiene las siguientes partes: una base (2, 2’, 2”), que tiene unos medios de apoyo (3, 3’, 3”) para situar la superficie de test (7) del microarray (6) en paralelo a una superficie de lectura (4) de la base (2, 2’, 2”); una matriz de transductores (5, 5’, 5”), dispuestos sobre la superficie de lectura (4) de la base (2, 2’, 2”), que traducen una variación de una magnitud eléctrica o química en una variación de una magnitud eléctrica; y unos medios de lectura (10), conectados a los transductores (5, 5’, 5”), que interpretan las señales eléctricas de los transductores (5, 5’, 5”).Peer reviewedConsejo Superior de Investigaciones Científicas (España)A1 Solicitud de patentes con informe sobre el estado de la técnic

    Primary structure and functional expression of a cyclic nucleotidegated channel from rabbit aorta

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    Sequences specific for cyclic nucleotide-gated channels (CNG channels) have been amplified by PCR from cDNA of heart, aorta, sinoatrial node, cerebellum, C-cells and kidney. The complete amino acid sequence of a CNG channel from rabbit aorta has been deduced by cloning and sequence analysis of the cDNA. Synthetic RNA derived from this cDNA induces the formation of a functional CNG channel in Xenopus oocytes

    The German fibromyalgia consumer reports - a cross-sectional survey

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    Background: Consumer surveys provide information on effectiveness and side effects of medical interventions in routine clinical care. A report of fibromyalgia syndrome (FMS) consumers has not been carried out in Europe. Methods: The study was carried out from November 2010 to April 2011. Participants diagnosed with FMS rated the effectiveness and side effects of pharmacological and non-pharmacological FMS interventions on a 0 to 10 scale, with 10 being most efficacious (harmful). The questionnaire was distributed by the German League for people with Arthritis and Rheumatism and the German Fibromyalgia Association to their members and to all consecutive FMS patients of nine clinical centers of different levels of care. Results: 1661 questionnaires (95% women, mean age 54 years, mean duration since FMS diagnosis 6.8 years) were analysed. The most frequently used therapies were self-management strategies, prescription pain medication and aerobic exercise. The highest average effectiveness was attributed to whole body and local warmth therapies, thermal bathes, FMS education and resting. The highest average side effects were attributed to strong opioids, local cold therapy, gamma-amino-butyric acid analogues (pregabalin and gabapentin), tramadol and opioid transdermal systems. Conclusion: The German fibromyalgia consumer reports highlight the importance of non-pharmcological therapies in the long-term management of FMS, and challenges the strong recommendations for drug therapies given by FMS-guidelines

    Validation of the Fibromyalgia Survey Questionnaire within a Cross-Sectional Survey

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    The Fibromyalgia Survey Questionnaire (FSQ) assesses the key symptoms of fibromyalgia syndrome. The FSQ can be administrated in survey research and settings where the use of interviews to evaluate the number of pain sites and extent of somatic symptom intensity and tender point examination would be difficult. We validated the FSQ in a cross-sectional survey with FMS patients. In a cross-sectional survey, participants with physician diagnosis of FMS were recruited by FMS-self help organisations and nine clinical institutions of different levels of care. Participants answered the FSQ (composed by the Widespread Pain Index [WPI] and the Somatic Severity Score [SSS]) assessing the Fibromyalgia Survey Diagnostic Criteria (FSDC) and the Patient Health Questionnaire PHQ 4. American College of Rheumatology 1990 classification criteria were assessed in a subgroup of participants. 1,651 persons diagnosed with FMS were included into analysis. The acceptance of the FSQ-items ranged between 78.9 to 98.1% completed items. The internal consistency of the items of the SSS ranged between 0.75–0.82. 85.5% of the study participants met the FSDC. The concordance rate of the FSDC and ACR 1990 criteria was 72.7% in a subsample of 128 patients. The Pearson correlation of the SSS with the PHQ 4 depression score was 0.52 (p<0.0001) and with the PHQ anxiety score was 0.51 (p<0.0001) (convergent validity). 64/202 (31.7%) of the participants not meeting the FSDC criteria and 152/1283 (11.8%) of the participants meeting the FSDC criteria reported an improvement (slightly too very much better) in their health status since FMS-diagnosis (Chi2 = 55, p<0.0001) (discriminant validity). The study demonstrated the feasibility of the FSQ in a cross-sectional survey with FMS-patients. The reliability, convergent and discriminant validity of the FSQ were good. Further validation studies of the FSQ in clinical and general population settings are necessary

    Global, regional, and national burden of chronic kidney disease, 1990–2017 : a systematic analysis for the Global Burden of Disease Study 2017

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    Background Health system planning requires careful assessment of chronic kidney disease (CKD) epidemiology, but data for morbidity and mortality of this disease are scarce or non-existent in many countries. We estimated the global, regional, and national burden of CKD, as well as the burden of cardiovascular disease and gout attributable to impaired kidney function, for the Global Burden of Diseases, Injuries, and Risk Factors Study 2017. We use the term CKD to refer to the morbidity and mortality that can be directly attributed to all stages of CKD, and we use the term impaired kidney function to refer to the additional risk of CKD from cardiovascular disease and gout. Methods The main data sources we used were published literature, vital registration systems, end-stage kidney disease registries, and household surveys. Estimates of CKD burden were produced using a Cause of Death Ensemble model and a Bayesian meta-regression analytical tool, and included incidence, prevalence, years lived with disability, mortality, years of life lost, and disability-adjusted life-years (DALYs). A comparative risk assessment approach was used to estimate the proportion of cardiovascular diseases and gout burden attributable to impaired kidney function. Findings Globally, in 2017, 1·2 million (95% uncertainty interval [UI] 1·2 to 1·3) people died from CKD. The global all-age mortality rate from CKD increased 41·5% (95% UI 35·2 to 46·5) between 1990 and 2017, although there was no significant change in the age-standardised mortality rate (2·8%, −1·5 to 6·3). In 2017, 697·5 million (95% UI 649·2 to 752·0) cases of all-stage CKD were recorded, for a global prevalence of 9·1% (8·5 to 9·8). The global all-age prevalence of CKD increased 29·3% (95% UI 26·4 to 32·6) since 1990, whereas the age-standardised prevalence remained stable (1·2%, −1·1 to 3·5). CKD resulted in 35·8 million (95% UI 33·7 to 38·0) DALYs in 2017, with diabetic nephropathy accounting for almost a third of DALYs. Most of the burden of CKD was concentrated in the three lowest quintiles of Socio-demographic Index (SDI). In several regions, particularly Oceania, sub-Saharan Africa, and Latin America, the burden of CKD was much higher than expected for the level of development, whereas the disease burden in western, eastern, and central sub-Saharan Africa, east Asia, south Asia, central and eastern Europe, Australasia, and western Europe was lower than expected. 1·4 million (95% UI 1·2 to 1·6) cardiovascular disease-related deaths and 25·3 million (22·2 to 28·9) cardiovascular disease DALYs were attributable to impaired kidney function. Interpretation Kidney disease has a major effect on global health, both as a direct cause of global morbidity and mortality and as an important risk factor for cardiovascular disease. CKD is largely preventable and treatable and deserves greater attention in global health policy decision making, particularly in locations with low and middle SDI
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