The power of coordinate transformations in dynamical interpretations of Galactic structure

ABSTRACT Gaia DR2 has provided an unprecedented wealth of information about the positions and motions of stars in our Galaxy and has highlighted the degree of disequilibria in the disc. As we collect data over a wider area of the disc, it becomes increasingly appealing to start analysing stellar actions and angles, which specifically label orbit space, instead of their current phase space location. Conceptually, while $\bar {x}$ and $\bar {v}$ tell us about the potential and local interactions, grouping in action puts together stars that have similar frequencies and hence similar responses to dynamical effects occurring over several orbits. Grouping in actions and angles refines this further to isolate stars that are travelling together through space and hence have shared histories. Mixing these coordinate systems can confuse the interpretation. For example, it has been suggested that by moving stars to their guiding radius, the Milky Way spiral structure is visible as ridge-like overdensities in the Gaia data (Khoperskov et al. 2020). However, in this work, we show that these features are in fact the known kinematic moving groups, both in the Lz − ϕ and the vR − vϕ planes. Using simulations, we show how this distinction will become even more important as we move to a global view of the Milky Way. As an example, we show that the radial velocity wave seen in the Galactic disc in Gaia and APOGEE should become stronger in the action-angle frame, and that it can be reproduced by transient spiral structure.

Relating the deBroglie and Compton Wavelengths to the Velocity of Light?

No report in the literature has directly described this relation. New constants for particles are presented. One relates to the Compton wavelength, called here the “mass-wave” constant for all particles. The other relates to the deBroglie wavelength, called here the “velocity-wave” constant for a particle. An equation is derived based on these two constants encapsulating a fundamental relation between the matter-states, particle and wave, to the velocity of light. New approaches to the Uncertainty relations are shown. The basic Schrodinger equation is derived from the perspective of a non-dimensional second-order differential equation free of any assumed empirical constants. The resulting time-dependent wave equation for a free particle was then expressed in terms of the particle velocity and deBroglie wavelength.

Theoretical analysis of a hybrid traffic model accounting for safe velocity

A hybrid traffic-flow model [Wang–Zhou–Yan (WZY) model] is brought out in this paper. In WZY model, the global equilibrium velocity is replaced by the local equilibrium one, which emphasizes that the modification of vehicle velocity is based on the view of safe-driving rather than the global deployment. In the view of safe-driving, the effect of drivers’ estimation is taken into account. Moreover, the linear stability of the traffic model has been performed. Furthermore, in order to test the robustness of the system, the evolvement of the density wave and the velocity wave of the traffic flow has been numerically calculated.

Ultrasonic Pulse Velocity Evaluation of the Pull-Off Adhesion between Epoxy Resin and Concrete Substrate

Adhesion assessment between epoxy resin and concrete substrate is described in the article. Two-layered cylindrical elements were obtained from the borehole in the object created for the purpose of the test. Adhesion analysis has been performed for two groups of elements of different composition. The ultrasonic pulse velocity (UPV) method with two-sided access was used to assess the adhesion. Pull-off adhesion fb compared with the ultrasonic wave velocity V has been determined. Relationships between the ultrasonic wave velocity V and pull-off adhesion fb, obtained with the semi-destructive pull-off method, were determined for both groups of elements. It was proved that together with an increase on the elements of the ultrasonic velocity wave V, the pull-off adhesion value fb between the epoxy resin and the concrete substrate also increases.

Investigation of Performance of High Velocity Air Intake Wave-Plate Separators for Marine Gas Turbines

Due to the advantages of great power, small size and light weight, the application of gas turbines in marine power facilities has increased a lot over time. Concerning the factors of off-shore operating environments which include the huge air intake quantity, the massive mist marine circumstance and the precious vessel available capacity, this paper combined experimental study with numerical simulation to investigate the performance of a type of new air intake wave-plate separator which can be applied under high intake velocity conditions. The total pressure drop was measured in a small wind tunnel with the inlet velocities of the separators ranging from 1.0 to 15.0 m/s. The resistance characteristics of high velocity wave-plate separators were simulated under the same velocity range described above. The separation efficiencies of high velocity wave-plate separators were simulated under the inlet velocity of 14.0 m/s, and the liquid diameters were 5μm, 10μm, 15μm and 20μm respectively. By analyzing the results of experiments and simulations, this paper draws the conclusion that high velocity wave-plate separators can keep high separation efficiencies and acceptable total pressure drop under high inlet velocities.

The Construction of Unsmooth Pulse Images in Traditional Chinese Medicine Based on Wave Intensity Technology

Unsmooth pulse is one of the most important pulses in TCM diagnostics. We constructed the wave intensity (WI) images of unsmooth pulse based on the pressure wave (P), flow velocity wave (U), and WI [(dP/dt)(dU/dt)] by ALOKA Prosound α 10 Color Doppler. The characteristic of Cunkou normal pulse could be summarized as follows: compared to Renying pulse, its W1 amplitude is smaller and NA wave is more obvious, while the W2 wave is indistinct or even invisible, and the R-1st is longer than that of Renying pulse. The principal U wave of Renying pulse looks like “Λ” shape, while it looks like an arched blunt “∩” shape in Cunkou pulse, and the amplitude of U wave in Cunkou pulse is smaller. The direction of the principal U wave in Cunkou unsmooth pulse is up, which shows hoof boots “h” shape with high amplitude and a significant notch on declined branch; the amplitude of predicrotic wave in unsmooth pulse P wave is significantly higher, which could be even higher than that of h1, resulting in early appearance of h3 or integrating with h1, which forms a wide and blunt peak. Unsmooth pulse shows poorer vascular elasticity and greater vascular stiffness.