The Beep-Speed Illusion Cannot Be Explained With a Simple Selection Bias

An object appears to move at higher speed than another equally fast object when brief nonspatial tones coincide with its changes in motion direction. We refer to this phenomenon as the beep-speed illusion (Meyerhoff et al., 2022, Cognition , 219 , 104978). The origin of this illusion is unclear; however, attentional explanations and potential biases in the response behavior appear to be plausible candidates. In this report, we test a simple bias explanation that emerges from the way the dependent variable is assessed. As the participants have to indicate the faster of the two objects, participants possibly always indicate the audio-visually synchronized object in situations of perceptual uncertainty. Such a response behavior potentially could explain the observed shift in perceived speed. We therefore probed the magnitude of the beep-speed illusion when the participants indicated either the object that appeared to move faster or the object that appeared to move slower. If a simple selection bias would explain the beep-speed illusion, the response pattern should be inverted with the instruction to indicate the slower object. However, contrary to this bias hypothesis, illusion emerged indistinguishably under both instructions. Therefore, simple selection biases cannot explain the beep-speed illusion

Heat transfer in separated flows on the pressure side of turbine blades

Heat transfer in separated flows on the pressure side of a typical high lift turbine profile is numerically investigated by means of an in-house CFD code. The numerical code was first validated on attached flows in turbine blades. To obtain flow separation cases, the profile is subject to large negative incidences so that a separation bubble is obtained at the pressure side. The numerical results are compared to available experimental data for code validation. It is shown how local minima and maxima values of the heat transfer coefficient are related to the separation and reattachment points, where the velocity component perpendicular to the wall is shown to have a significant effect on the heat transfe

Semi-Automatic Cell Correspondence Analysis Using Iterative Point Cloud Registration

In the field of biophysics, deformation of in-vitro model tissues is an experimental technique to explore the response of tissue to a mechanical stimulus. However, automated registration before and after deformation is an ongoing obstacle for measuring the tissue response on the cellular level. Here, we propose to use an iterative point cloud registration (IPCR) method, for this problem. We apply the registration method on point clouds representing the cellular centers of mass, which are evaluated with aWatershed based segmentation of phase-contrast images of living tissue, acquired before and after deformation. Preliminary evaluation of this method on three data sets shows high accuracy, with 82% - 92% correctly registered cells, which outperforms coherent point drift (CPD). Hence, we propose the application of the IPCR method on the problem of cell correspondence analysis

Study on S-shape instabilities and pressure pulsations in reversible pump-turbines: Conflictive mechanisms behind a varying rotor-stator distance and development of a new guide vane design for improving transient behavior during turbine start-up and in case of load-rejection

Abstract Increasing demands towards a more flexible and reliable operation of backbone systems for electrical grid stability has been leading to an upsurge of pumped-storage in the last years. As technological requirements concerning reversible pump-turbines have been undergone substantial transformations with respect to operational stability and noise emission, hydraulic designs are prompted to change according to market needs and requirements. One of the main factors threatening the mechanical structure of components represents the unstable operation in pump and turbine mode. Instabilities are typically accompanied by an intense increase in pressure pulsations that can be a main reason for vibration issues and resonance excitations in reversible pump-turbines. Avoiding instabilities during operation is, therefore, one of the major targets for competitive designs. This paper emphasizes the relevance of a thorough analysis of S-shape instabilities and provides an explanation of their underlying mechanisms based on analytical, numerical and experimental methods. It also addresses conflictive mechanisms behind a varying rotor-stator distance that could occur in terms of operational stability and rotor-stator interaction. The introduction of a new 3D-shaped guide vane design represents a further key outcome of this study. With respect to a varying rotor-stator distance, special attention has been paid to the description of influencing factors for turbine stability and pressure pulsations using three rescaled versions of an existing guide vane design. Series of model tests have been conducted on a test rig at ANDRITZ in Linz, Austria, revealing whether a measure is competitive based on the layout of a 2x330MW variable-speed pump-turbines plant.</jats:p

External Heat Transfer Predictions in a Highly Loaded Transonic Linear Turbine Guide Vane Cascade Using an Upwind Biased Navier–Stokes Solver

External heat transfer predictions are performed for two-dimensional turbine blade cascades. The Reynolds-averaged Navier–Stokes equations with algebraic (Arnone and Pacciani, 1998), one-equation (Spalart and Allmaras, 1994), and two-equation (low-Re k–ε, Biswas and Fukuyama, 1994) turbulence closures are solved with a fully implicit time-marching finite volume method. Comparisons with measurements (Arts et al., 1990; Arts, 1994) for a highly loaded transonic turbine nozzle guide vane cascade show good agreement in some cases, but also reveal problems with transition prediction and turbulence modeling. Special attention has been focused on the low-Re k–ε model concerning the influence of the inlet boundary condition for the ε-equation and problems in the stagnation point region.</jats:p