151 research outputs found

    Nonlinear MHD simulation of core plasma collapse events in Wendelstein 7-X

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    Three-dimensional nonlinear MHD simulations study the core collapse events observed in a stellarator experiment, Wendelstein 7-X. In the low magnetic shear configuration like the Wendelstein 7-X, the rotational transform profile is very sensitive to the toroidal current density. The 3D equilibrium with localized toroidal current density is studied. If the toroidal current density follows locally in the middle of the minor radius, the rotational transform is also changed locally. Sometimes, the magnetic topology changes due to appearing the magnetic island. A full three-dimensional nonlinear MHD code studies the nonlinear behaviors of the MHD instability. It was found that the following sequence. At first, the high-n ballooning-type mode structure appears in the plasma core, and then the mode linearly grows. The high-n ballooning modes nonlinearly couple and saturate. The mode structure changes to the low-n mode. The magnetic field structure becomes strongly stochastic into the plasma core due to the nonlinear coupling in that phase. Finally, the plasma pressure diffuses along the stochastic field lines, and then the core plasma pressure drops. This is a crucial result to interpret the core collapse event by strong nonlinear coupling.Peer ReviewedPostprint (published version

    Virtual 3D City Model Support for Energy Demand Simulations on City Level – The CityGML Energy Extension

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    Due to the transition from fossil energy carriers to more renewable energy resources, the availability of energy in future will be fluctuating. Under these conditions, an accurate energy demand simulation for buildings is strongly needed as planning instrument on district or city level. This paper introduces a new data model for the energy relevant properties of buildings. It extends the existing standard CityGML for 3D city models by energy relevant properties like, e.g., physical materials, thermal zones and thermal boundaries, and building occupant's behaviour. The energy extension of CityGML is designed as system-independent interface to energy simulation systems and shall support detailed simulation on the level of single buildings as well as energy demand assessments on district and city level

    Thermal Energy Simulation of Buildings based on the CityGML Energy Application Domain Extension

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    The present paper describes a semi-automatic process, in which a typical CityGML 3D building model is enriched with explicit thermal energy related information and stored in a CityGML Application Domain Extension (ADE). Special emphasis is given to the discussion of suitability of existing CityGML models for city-wide energy simulations. Possible conflicts between the requirements of urban energy simulation systems, the capabilities of the CityGML Energy ADE and the available data are presented, which can be partly resolved by specific geometric / semantic corrections of the model data. For testing and evaluating the approach, interfaces for two building energy simulation systems have been developed

    A comprehensive evaluation of the activity and selectivity profile of ligands for RGD-binding integrins

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    Integrins, a diverse class of heterodimeric cell surface receptors, are key regulators of cell structure and behaviour, affecting cell morphology, proliferation, survival and differentiation. Consequently, mutations in specific integrins, or their deregulated expression, are associated with a variety of diseases. In the last decades, many integrin-specific ligands have been developed and used for modulation of integrin function in medical as well as biophysical studies. The IC50-values reported for these ligands strongly vary and are measured using different cell-based and cell-free systems. A systematic comparison of these values is of high importance for selecting the optimal ligands for given applications. In this study, we evaluate a wide range of ligands for their binding affinity towards the RGD-binding integrins avß3, avß5, avß6, avß8, a5ß1, aIIbß3, using homogenous ELISA-like solid phase binding assay.Postprint (published version

    Building Information Modelling in der Konzeptionsphase der Planung

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    In diesem Beitrag wird die Anwendung Early Design Configurator (EDC) vorgestellt, die in der Konzeptionsphase Layouts erzeugt und präsentiert. Als Eingabeparameter für die Erzeugung von Layouts werden Umrisse des Gebäudes, das Raumbuch und Entwurfsregeln benötigt. Die Generierung der Raum-Grundrisse des geplanten Gebäudes erfolgt automatisch mit einem evolutionären Algorithmus, in dessen Zielfunktion die Anforderungen und Restriktionen von Raumbuch und Entwurfsregeln eingehen. Durch mehrfache Ausführung des evolutionären Algorithmus lassen sich bei veränderter Gewichtung der Regeln verschiedene Layouts erzeugen. Der beschriebene Prozess zielt nicht darauf ab, fertig geplante Gebäudemodelle automatisiert zu generieren, sondern die Informationen aus der Konzeptionsphase als Building Information Model in den Lebenszyklus des Gebäudes einzubringen

    Cardiac Output Measurements in Septic Patients: Comparing the Accuracy of USCOM to PiCCO

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    USCOM is an ultrasound-based method which has been accepted for noninvasive hemodynamic monitoring in various clinical conditions (USCOM, Ultrasonic cardiac output monitoring). The present study aimed at comparing the accuracy of the USCOM device with that of the thermodilution technique in patients with septicemia. We conducted a prospective observational study in a medical but noncardiological ICU of a university hospital. Septic adult patients (median age 55 years, median SAPS-II-Score 43 points) on mechanical ventilation and catecholamine support were monitored with USCOM and PiCCO (n = 70). Seventy paired left-sided CO measurements (transaortic access = COUS-A) were obtained. The mean COUS-A were 6.55 l/min (±2.19) versus COPiCCO 6.5 l/min (±2.18). The correlation coefficient was r = 0.89. Comparison by Bland-Altman analysis revealed a bias of −0.36 l/min (±0.99 l/min) leading to a mean percentage error of 29%. USCOM is a feasible and rapid method to evaluate CO in septic patients. USCOM does reliably represent CO values as compared to the reference technique based on thermodilution (PiCCO). It seems to be appropriate in situations where CO measurements are most pertinent to patient management

    Extension of the SIESTA MHD equilibrium code to free-plasma-boundary problems

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    is a recently developed MHD equilibrium code designed to perform fast and accurate calculations of ideal MHD equilibria for three-dimensional magnetic configurations. Since SIESTA does not assume closed magnetic surfaces, the solution can exhibit magnetic islands and stochastic regions. In its original implementation SIESTA addressed only fixed-boundary problems. That is, the shape of the plasma edge, assumed to be a magnetic surface, was kept fixed as the solution iteratively converges to equilibrium. This condition somewhat restricts the possible applications of SIESTA. In this paper, we discuss an extension that will enable SIESTA to address free-plasma-boundary problems, opening up the possibility of investigating problems in which the plasma boundary is perturbed either externally or internally. As an illustration, SIESTA is applied to a configuration of the W7-X stellarator.This research was funded in part by the Ministerio de Economía, Industria y Competitividad of Spain, Grant No. ENE2015-68265. This research was carried out in part at the Max-Planck-Institute for Plasma Physics in Greifswald (Germany), whose hospitality is gratefully acknowledged. This research was supported in part by the U.S. Department of Energy, Office of Fusion Energy Sciences under Award DE-AC05-00OR22725. SIESTA runs have been carred out in Uranus, a supercomputer cluster located at Universidad Carlos III de Madrid and funded jointly by the European Regional Development Funds (EU-FEDER) Project No. UNC313-4E-2361, and by the Ministerio de Economía, Industria y Competitividad via the National Project Nos. ENE2009-12213-C03-03, ENE2012-33219, and ENE2012-31753

    Mortality of Patients with Hematological Malignancy after Admission to the Intensive Care Unit

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    Background: The admission of patients with malignancies to an intensive care unit (ICU) still remains a matter of substantial controversy. The identification of factors that potentially influence the patient outcome can help ICU professionals make appropriate decisions. Patients and Methods: 90 adult patients with hematological malignancy (leukemia 47.8%, high-grade lymphoma 50%) admitted to the ICU were analyzed retrospectively in this single-center study considering numerous variables with regard to their influence on ICU and day-100 mortality. Results: The median simplified acute physiology score (SAPS) II at ICU admission was 55 (ICU survivors 47 vs. 60.5 for non-survivors). The overall ICU mortality rate was 45.6%. With multivariate regression analysis, patients admitted with sepsis and acute respiratory failure had a significantly increased ICU mortality (sepsis odds ratio (OR) 9.12, 95% confidence interval (CI) 1.1-99.7, p = 0.04; respiratory failure OR 13.72, 95% CI 1.39-136.15, p = 0.025). Additional factors associated with an increased mortality were: high doses of catecholamines (ICU: OR 7.37, p = 0.005; day 100: hazard ratio (HR) 2.96, p < 0.0001), renal replacement therapy (day 100: HR 1.93, p = 0.026), and high SAPS II (ICU: HR 1.05, p = 0.038; day 100: HR 1.2, p = 0.027). Conclusion: The decision for or against ICU admission of patients with hematological diseases should become increasingly independent of the underlying malignant disease

    Bone Loss after Allogeneic Haematopoietic Stem Cell Transplantation: A Pilot Study on the Use of Zoledronic Acid

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    Purpose. Bone loss is a common phenomenon following allogeneic haematopoietic stem cell transplantation (allo-HSCT). The study aimed on tolerance and efficacy of zoledronic acid (ZA) in patients after allo-HSCT. Methods. 40 patients' with osteoporosis or osteopenia were recruited on this phase II study. ZA was given at a dose of 4 mg IV every 3 months for 2 years (yrs). BMD was determined by dual-energy X-ray absorptiometry (LS lumbar spine, FH femur hip). Patients were evaluated for deoxypyridinoline (Dpd) and calcium excretion by longitudinal measurements. Results. 36 patients who had received at least 3 doses of ZA were evaluable. 26 patients had at least two BMD measurements since baseline (BMD group). Among these patients, BMD increased from 0.97 ± 0.15 to 1.10 ± 0.18 g/cm² (LS baseline—2 yrs, Δ+11.6 ± 6.0%, P < 0.001) and from 0.82 ± 0.10 to 0.91 ± 0.10 g/cm² (FH baseline—2 yrs, Δ+7.5 ± 7.0%, P < 0.001). Factors associated with an increase in BMD were younger age, female donor sex, and immunosuppression with CSA/MTX. Conclusion. ZA was generally well tolerated; it increases BMD and reduces Dpd excretion significantly in patients with bone loss after allo-HSCT

    Applications of the SCENIC code package to the minority ion-cyclotron heating in Wendelstein 7-X plasmas

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    We present SCENIC simulations of a W7X 4He plasma with 1% H minority and with an antenna model close to the design foreseen for the W7X ICRF antenna [1, 2]. A high mirror and a standard equilibrium are considered. The injected wave frequency is fixed at 33.8 MHz and 39.6MHz respectively and only fundamental minority heating is considered. Included in this calculation is a new realistic model of the antenna, where it is found that the localization of the antenna geometry tends to break the five-fold periodicity of the system. We assess the heat transfer through the toroidal periods via Coulomb collisions
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