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Dimensionierung und Modellierung von Radialverdichtern im initialen Triebwerksentwurf
No full textDie stetige Erhöhung des Gesamtdruckverhältnisses zur Verringerung des spezifischen Brennstoffverbrauches führt in Hochdruckverdichtern zu sehr kleinen Kanalhöhen. Daher werden in Turboprops und kleinen Turbofans, Hochdruckverdichter als zweistufige Radialverdichter oder in Mischbauweise als Axial-Radialverdichter ausgeführt. Ziel dieser Arbeit ist die schnelle und robuste Auslegung von Radialverdichtern als einzelne Stufe oder als radiale Endstufe im mehrstufigen Verdichter. Am Beispiel des Technologieträgers iSTAR wurde der initiale Vorentwurf des mehrstufigen Hochdruckverdichters durchgeführt. Der mehrstufige Axial-Radialverdichter liefert im Auslegungspunkt ein Gesamtdruckverhältnis von 15 bei einer Leistungsabgabe von 2,2 MW. Abschließend wurde das vollständige Verdichterkennfeld mit Hilfe eines 3D-CFD-Verfahrens ermittelt, einschließlich der Leitradverstellung und deren Einfluss auf das Betriebsverhalten des Verdichters
Wearable cardioverter defibrillator after ICD-system explantation
No full textData on the use of the wearable cardioverter defibrillator (WCD) among patients after cardiac implantable electronic device explantation of 1- to 3-chamber implantable cardioverter defibrillator systems (ICD) are sparse. Accordingly, several guidelines give a different recommendation regarding WCD indication in this cohort. We aimed to study the baseline characteristics and outcome of patients treated with WCD after ICD explantation. The primary outcome is appropriate WCD shock. Within a multicenter registry 109 patients received a WCD to bridge the time after ICD-system explantation until reimplantation due to a persistent ICD-indication. The mean follow-up was 824 773 days. In addition to ventricular tachyarrhythmias and/or WCD shocks during WCD wear time, also the rate of rehospitalization for ventricular tachyarrhythmias, atrial fibrillation, stroke and congestive heart failure after ICD-reimplantation was evaluated. Patients had a mean age of 65 14 years, and were hospitalized for 21 15 days. The index left ventricular ejection fraction (LVEF) was at baseline 35.7 14.1% and 35.7 14.2% at short-term follow-up. Mean wear time of the WCD was 61 46 days after ICD-system explantation. During that time an appropriate WCD shock was documented in 7.3% of patients. Up to 80.6% of patients after ICD-system explantation were re-implanted. The rates of rehospitalization due to ventricular tachyarrhythmias, heart failure and atrial fibrillation were 7.3%, 6.8% and 4.1%, respectively. After ICD-reimplantation the rate of appropriate shocks was 12/89 (13.4%). Occurrence of malignant ventricular tachyarrythmia after ICD-system explantation is high and the use of WCD among these patients could be beneficial in preventing sudden cardiac death
Comparing a new visuospatial intervention administered 3 days after a trauma film to reduce the occurrence of intrusive visual memories
No full text Intrusive memories occur frequently after potentially traumatic events and form a core symptom of posttraumatic stress disorder (PTSD) if they persist. The translational approach of visuospatial interventions tries to target those intrusive memories in order to reduce their frequency predominantly using an intervention including as one component the computer game . Despite promising results, the application of has critical drawbacks, e.g., potential commercial or copyright issues. Furthermore, it remains unclear whether it is this specific game or, as predicted by theory, a visuospatial task per se that leads to the effect. This study hence aims to compare the effect of with an alternative, bespoke visuospatial task: developed for the current purpose.
= 120 healthy participants watched a trauma film and recorded their intrusive memories in a diary for 6 days. Three days after watching the film, they were randomized to 3 groups and after memory reactivation cue received either or or (no task). Prior to intervention 8 participants reported zero intrusive memories to the film and were excluded from further analyses, therefore 112 participants were included in the analysis.
A mixed Poisson regression model revealed that the group had significantly less frequent intrusive memories after the intervention compared to the control condition (approximately 43%, = 0.0013). There was no significant difference for the group compared to (\it {Control}\) (17% less frequent, = 0.3798).
Our results suggest that visuospatial tasks other than — in this case, — can also lead to a reduction in intrusive memories when administered 3 days after a trauma film. This strengthens the assumption that it is not specifically the game , but rather the visuospatial nature of the task, that is responsible for the reduction. Aspects of further investigating the potential of as well as clinical implications are discussed