SACCON Forced Oscillation Tests at DNW-NWB and NASA Langley 14x22-Foot Tunnel

A series of three wind tunnel static and forced oscillation tests were conducted on a generic unmanned combat air vehicle (UCAV) geometry. These tests are part of an international research effort to assess the state-of-the-art of computational fluid dynamics (CFD) methods to predict the static and dynamic stability and control characteristics. The experimental dataset includes not only force and moment time histories but surface pressure and off body particle image velocimetry measurements as well. The extent of the data precludes a full examination within the scope of this paper. This paper provides some examples of the dynamic force and moment data available as well as some of the observed trends

Time-to-effect guided pulmonary vein isolation utilizing the third-generation versus second generation cryoballoon: One year clinical success

Background: The second-generation cryoballoon (CB2) provides effective and durable pulmonary vein isolation (PVI) associated with encouraging and reproducible clinical outcome data. The latest- -generation cryoballoon (CB3) incorporates a 40% shorter distal tip, thus allowing for an increased rate of PVI real-time signal recording and facilitating individualized ablation strategies taking the time-to- -effect (TTE) into account. However, whether this characteristic translates into favorable clinical success has not been evaluated yet. Herein was investigated 1-year clinical success after CB3 in comparison to CB2 based-PVI. Methods: One hundred and ten consecutive patients with paroxysmal or short-standing persistent atrial fibrillation (AF) underwent CB2 (n = 55 patients) -or CB3 (n = 55 patients) -based PVI. The freeze-cycle duration was set to TTE + 120 s if TTE could be recorded, otherwise a fixed freeze-cycle duration of 180 s was applied. Results: A total of 217/218 (99%, CB3) and 217/217 (100%, CB2) pulmonary veins (PV) were successfully isolated. The real-time PVI visualization rate was 69.2% (CB3) and 54.8% (CB2; p = 0.0392). The mean freeze-cycle duration was 194 ± 77 s (CB3) and 206 ± 85 s (CB2; p = 0.132), respectively. During a median follow-up of 409 days (interquartile range [IQR] 378–421, CB3) and 432 days (IQR 394–455, CB2) 73.6% (CB3) and 73.1% of patients (CB2) remained in stable sinus rhythm after a single procedure (p = 0.806). Conclusions: A higher rate of real-time electrical PV recordings was seen using the CB3 as compared to CB2. There was no difference in 1-year clinical follow-up

Improvement of the Automatic Grid Adaptation for Vortex Dominated Flows using Advanced Vortex Indicators with the DLR-TAU Code.

Vortex dominated flows appear in many flow simulations such as wake turbulence of an aircraft or a delta wing at a high angle of attack. For detailed investigations of vortex breakdown, vortex interactions or tracing vortex cores, an automated grid adaptation with suitable vortex indicators is essential. Physical indicators, e.g. the vorticity magnitude or the total pressure loss, are in most cases not sufficient for correctly identifying a vortex core. This paper presents advanced vortex core indicators which properly identify a vortical structure independent of the flow case. These vortex indicators are tested in typical flow applications to determine the right cut-off value which is important for an automated adaptation procedure. A grid refinement for a delta wing testcase in combination with the newly introduced vortex indicators will demonstrate the improvements compared to the standard pressure loss indicator

Procalcitonin-guided antibiotic treatment in critically ill patients

In critically ill patients, length of antibiotic treatment can be effectively guided by procalcitonin (PCT) protocols. International sepsis guidelines and guidelines on antibiotic stewardship strategies recommend PCT as helpful laboratory marker for a rational use of antibiotics. A number of studies and meta-analyses have confirmed the effectiveness of PCT-protocols for shortening antibiotic treatment without compromising clinical outcome in critically ill patients. But in clinical practice, there is still uncertainty how to interpret PCT levels and how to adjust antibiotic treatment in various infectious situations, especially in the perioperative period. This narrative review gives an overview on the application of PCT-protocols in critically ill patients with severe bacterial infections on the basis of 5 case reports and the available literature. Beside strengths and limitations of this biomarker, also varying kinetics and different maximum values with regard to the infectious focus and pathogens are discussed. PCT-guided antibiotic treatment appears to be safe and effective. Most of the studies revealed a shorter antibiotic treatment without negative clinical outcomes. Cost effectiveness is still a matter of debate and effects on bacterial resistance due to shorter treatments, possible lower rates of drug-related adverse events, or decreased rates of Clostridium difficile infections are not yet evaluated. Guidance of antibiotic treatment can effectively be supported by PCT-protocols. However, it is important to consider the limitations of this biomarker and to use PCT protocols along with antibiotic stewardship programmes and regular clinical rounds together with infectious diseases specialists

Comparison of Reduced Order Models for Evaluating Stability Derivatives for the DLR-F22 ONERA model

This paper presents a comparison of reduced order models to predict aerodynamic stability derivatives. The study involved two widely used frameworks for simulating unsteady flows, DoD HPCMP CREATERM-AV/Kestrel and the DLR TAU code. The DLR TAU code contains a linearized version of the discrete unsteady Reynolds-averaged Navier-Stokes equations based on the small perturbation approach which are solved in the frequency domain. This allows a comparison with distinctly different approaches of reduced order aerodynamic modeling. The first approach is based on the linear frequency domain solver which computes stability derivatives directly. Three reduced order models are applied to unsteady simulations to extract stability derivatives from predicted time histories of the force and moment coefficients. The first reduced order model is the stability derivatives method. The second reduced order model is based on the calculated indicial responses to unit step changes in the angle of attack and pitch rate. Furthermore, a system identification approach is applied to the time history of the force and moment coefficients for different training maneuvers to extract the stability derivatives. The weaknesses and strengths of the individual approaches of reduced order models are shown and, in particular, the efficiency of the methods is outlined. The use case is the DLR-F22 ONERA model, a generic research wind tunnel model of a triple delta wing fighter type aircraft configuration, at transonic flow conditions for various angles of attack

A First Look on 3D Effects in Open Axion Haloscopes

We explore finite size 3D effects in open axion haloscopes such as a dish antenna, a dielectric disk and a minimal dielectric haloscope consisting of a mirror and one dielectric disk. Particularly dielectric haloscopes are a promising new method for detecting dark matter axions in the mass range above $40\,\mu{\rm eV}$. By using two specialized independent approaches - based on finite element methods and Fourier optics - we compute the electromagnetic fields in these settings expected in the presence of an axion dark matter field. This allows us to study diffraction and near field effects for realistically sized experimental setups in contrast to earlier idealized 1D studies with infinitely extended mirrors and disks. We also study axion velocity effects and disk tiling. Diffraction effects are found to become less relevant towards larger axion masses and for the larger disk radii for example aimed at in full size dielectric haloscopes such as MADMAX. The insights of our study not only provide a foundation for a realistic modelling of open axion dark matter search experiments in general, they are in particular also the first results taking into account 3D effects for dielectric haloscopes

Time-to-effect guided pulmonary vein isolation utilizing the third-generation versus second generation cryoballoon: One year clinical success

The second-generation cryoballoon (CB2) provides effective and durable pulmonary vein isolation (PVI) associated with encouraging and reproducible clinical outcome data. The latest-generation cryoballoon (CB3) incorporates a 40% shorter distal tip, thus allowing for an increased rate of PVI real-time signal recording and facilitating individualized ablation strategies taking the time-to-effect (TTE) into account. However, whether this characteristic translates into favorable clinical success has not been evaluated yet. Herein was investigated one-year clinical success after CB3 in comparison to CB2 based-PVI