Refracted wave in a horizontally stratified medium with constant velocity gradients

1969 ◽  
Vol 13 (4) ◽  
pp. 423-443 ◽  
Author(s):  
Jaromír Janský
Keyword(s):  
Constant Velocity ◽  
Stratified Medium ◽  
Velocity Gradients

Hydrodynamic evaluation of the influence of outlet configuration for mechanical flocculation facilities

2015 ◽  
Vol 16 (1) ◽  
pp. 17-25
Author(s):  
J. L. Cestari ◽  
T. Matsumoto ◽  
D. Gebara ◽  
M. Dall'Aglio Sobrinho ◽  
M. Libânio
Keyword(s):  
Water Treatment ◽  
Velocity Gradient ◽  
Constant Velocity ◽  
Short Circuit ◽  
Pilot Scale ◽  
Vertical Shaft ◽  
Velocity Gradients ◽  
Water Treatment Plants ◽  
Financial Investments ◽  
Hydrodynamic Evaluation

This paper focuses on hydrodynamic research aiming at the short-circuit evaluation of five different outlet configurations through the compartments of a mechanical flocculation unit of vertical shaft with mixing paddles at pilot scale. The tests were carried out with two, three and four compartments, variable and constant velocity gradients, including alternating senses of paddle rotation (clockwise in the first compartment, anticlockwise in the following one and so on). The research pointed out that the relevance of outlet configuration increases with the reduction of the number of compartments. In opposite, the velocity gradient and the sense of the paddle rotation seem less significant features. These results suggest the possibility of a viable increasing of performance, with low financial investments, mainly for flocculation units with three or two compartments installed in overloaded water treatment plants.

Wavefront curvatures in three‐dimensional laterally inhomogeneous media with curved interfaces

Geophysics ◽  
1980 ◽  
Vol 45 (5) ◽  
pp. 905-913 ◽  
Author(s):  
Peter Hubral
Keyword(s):  
Matrix Equation ◽  
Constant Velocity ◽  
Analytic Solution ◽  
Three Dimensional ◽  
Inhomogeneous Media ◽  
System Of Equations ◽  
First Order ◽  
Velocity Gradients ◽  
Differential Matrix

The curvatures of a wavefront along a ray in laterally inhomogenous three‐dimensional velocity media separated by curved first‐order interfaces can be computed by a system of equations that includes a Riccati‐type differential matrix equation. This has a simple analytic solution along circular raypaths in media of constant velocity gradients.

Record Wear Studies by Scanning Electron Microscopy

1968 ◽  
Vol 26 ◽  
pp. 364-365
Author(s):  
M.D. Coutts ◽  
E.R. Levin ◽  
J.G. Woodward
Keyword(s):  
Electron Microscopy ◽  
Constant Velocity ◽  
Peak Velocity ◽  
Great Depth ◽  
Depth Of Focus ◽  
Sweep Frequency ◽  
Transmission Electron ◽  
Test Record ◽  
Lateral Mode ◽  
Scanning Electron

While record grooves have been studied by transmission electron microscopy with replica techniques, and by optical microscopy, the former are cumbersome and restricted and the latter limited by lack of depth of focus and resolution at higher magnification. With its great depth of focus and ease in specimen manipulation, the scanning electron microscope is admirably suited for record wear studies.A special RCA sweep frequency test record was used with both lateral and vertical modulation bands. The signal is a repetitive, constant-velocity sweep from 2 to 20 kHz having a duration and repetitive rate of approximately 0.1 sec. and a peak velocity of 5.5 cm/s.A series of different pickups and numbers of plays were used on vinyl records. One centimeter discs were then cut out, mounted and coated with 200 Å of gold to prevent charging during examination. Wear studies were made by taking micrographs of record grooves having 1, 10 and 50 plays with each stylus and comparing with typical “no-play” grooves. Fig. 1 shows unplayed grooves in a vinyl pressing with sweep-frequency modulation in the lateral mode.

Developing an inkjet printer IV: printer mechanism control for best print quality

2020 ◽  
Vol 2020 (15) ◽  
pp. 349-1-349-9
Author(s):  
Daulet Kenzhebalin ◽  
Baekdu Choi ◽  
Sige Hu ◽  
Yin Wang ◽  
Davi He ◽  
...  
Keyword(s):  
Motor Control ◽  
Constant Velocity ◽  
Control Problems ◽  
Print Quality ◽  
Control Parameters ◽  
Test Page ◽  
Mechanism Control ◽  
Testing Accuracy ◽  
Inkjet Printer

Inkjet printer motor control consists of moving the printhead in the scan direction and in the process direction. Both movements have different objectives. Scan direction movement needs to have constant velocity and process direction movement needs to have accurate movement. In this paper, we discuss a method for controlling the velocity of the printhead and how to tune the motor control parameters. We also design six test pages for testing accuracy of the printhead movement and cartridge properties. For each test page, we discuss expected prints, common printer control problems that could alter the print quality, and how to identify them.

scholarly journals A synergy of the velocity gradients technique and the probability density functions for identifying gravitational collapse in self-absorbing media

2021 ◽  
Vol 502 (2) ◽  
pp. 1768-1784
Author(s):  
Yue Hu ◽  
A Lazarian
Keyword(s):  
Magnetic Fields ◽  
Probability Density ◽  
Column Density ◽  
Mass Density ◽  
Probability Density Functions ◽  
Emission Lines ◽  
Density Functions ◽  
Star Forming ◽  
Velocity Gradients ◽  
Self Gravity

ABSTRACT The velocity gradients technique (VGT) and the probability density functions (PDFs) of mass density are tools to study turbulence, magnetic fields, and self-gravity in molecular clouds. However, self-absorption can significantly make the observed intensity different from the column density structures. In this work, we study the effects of self-absorption on the VGT and the intensity PDFs utilizing three synthetic emission lines of CO isotopologues 12CO (1–0), 13CO (1–0), and C18O (1–0). We confirm that the performance of VGT is insensitive to the radiative transfer effect. We numerically show the possibility of constructing 3D magnetic fields tomography through VGT. We find that the intensity PDFs change their shape from the pure lognormal to a distribution that exhibits a power-law tail depending on the optical depth for supersonic turbulence. We conclude the change of CO isotopologues’ intensity PDFs can be independent of self-gravity, which makes the intensity PDFs less reliable in identifying gravitational collapsing regions. We compute the intensity PDFs for a star-forming region NGC 1333 and find the change of intensity PDFs in observation agrees with our numerical results. The synergy of VGT and the column density PDFs confirms that the self-gravitating gas occupies a large volume in NGC 1333.

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