Laboratory measurements of a phase shift in the reflection from a water-mud interface due to water column variability

Gabriel R. Venegas; Preston S. Wilson

doi:10.1121/1.4970701

Confined Plunging Liquid Jets for Dilution of Brine from Desalination Plants

Processes ◽

10.3390/pr9050856 ◽

2021 ◽

Vol 9 (5) ◽

pp. 856

Author(s):

Ishita Shrivastava ◽

Edward Eric Adams ◽

Bader Al-Anzi ◽

Aaron Chunghin Chow ◽

Jongyoon Han

Keyword(s):

Water Column ◽

Penetration Depth ◽

Water Surface ◽

Liquid Jets ◽

Laboratory Measurements ◽

Surrounding Water ◽

Plunging Jets ◽

Desalination Plants ◽

Negative Buoyancy

Confined plunging jets are investigated as potential outfalls for the discharge of desalination brine. Compared to offshore submerged outfalls that rely on momentum to induce mixing, plunging jets released above the water surface utilize both momentum and negative buoyancy. Plunging jets also introduce air into the water column, which can reduce the possibility of hypoxic zones. In contrast to unconfined plunging jets, confined plunging jets include a confining tube, or downcomer, around the jet, which increases the penetration depth of the bubbles and can provide better aeration. However, the presence of this downcomer can hinder mixing with surrounding water. Therefore, laboratory measurements of dilution are reported here and compared to the dilution of unconfined plunging jets. In addition, qualitative observations of bubble penetration depth are also used to discuss aeration potential. For designs that increase the bubble penetration depth as compared to unconfined plunging jets, results show that dilution decreases as the depth of the downcomer is increased. However, it is shown that confined plunging jets can be designed with a short downcomer to provide higher dilution than unconfined jets. The effect of the diameter of downcomer on dilution is also investigated and a non-monotonic effect is observed.

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Integer- and Fractional-Order VCO Using Non-Inertial Amplitude Stabilization and Modern Active Elements

Elektronika ir Elektrotechnika ◽

10.5755/j01.eie.26.2.25903 ◽

2020 ◽

Vol 26 (2) ◽

pp. 42-47

Author(s):

Roman Sotner ◽

Jiri Petrzela ◽

Jan Jerabek ◽

Lukas Langhammer ◽

Josef Polak ◽

...

Keyword(s):

Phase Shift ◽

Fractional Order ◽

Oscillation Frequency ◽

Initial Study ◽

Voltage Controlled Oscillator ◽

Laboratory Measurements ◽

Active Elements ◽

Amplitude Stabilization ◽

Gain Adjustment ◽

Single Path

This paper introduces design of the linearly tunable quadrature voltage-controlled oscillator (VCO) using modern off-the-shelf active elements suitable for the design of electronically adjustable applications. The simplified topology was achieved using non-inertial stabilization of amplitude. It allows targeting adjustability of the oscillation frequency only into lossless integrator part of the topology. This arrangement simplifies the design and the tenability also. Derived symbolical expressions indicate that gain adjustment of used amplifiers (that are still in single path) does not influence amplitude and phase shift ratio of generated waveforms, which is a beneficial feature. The performances of the circuit are tested experimentally in band of units of MHz and results confirmed expected behavior. Initial study of the oscillator with fractional-order capacitors is presented and discussed. Results are supported by laboratory measurements.

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Object Wave Determination by Single-Sideband Methods

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100071776 ◽

1973 ◽

Vol 31 ◽

pp. 266-267

Author(s):

Kenneth H. Downing ◽

Benjamin M. Siegel

Keyword(s):

Phase Shift ◽

Carbon Films ◽

Object Wave ◽

Electron Wave ◽

Phase Object ◽

Heavy Atoms ◽

Single Sideband ◽

Thin Carbon ◽

Additional Phase Shift ◽

Additional Phase

Under the “weak phase object” approximation, the component of the electron wave scattered by an object is phase shifted by π/2 with respect to the unscattered component. This phase shift has been confirmed for thin carbon films by many experiments dealing with image contrast and the contrast transfer theory. There is also an additional phase shift which is a function of the atomic number of the scattering atom. This shift is negligible for light atoms such as carbon, but becomes significant for heavy atoms as used for stains for biological specimens. The light elements are imaged as phase objects, while those atoms scattering with a larger phase shift may be imaged as amplitude objects. There is a great deal of interest in determining the complete object wave, i.e., both the phase and amplitude components of the electron wave leaving the object.

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A Many-Beam Technique for Enhanced Resolution of Partial Dislocations

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100096485 ◽

1972 ◽

Vol 30 ◽

pp. 646-647

Author(s):

J. M. Oblak ◽

B. H. Kear

Keyword(s):

Phase Shift ◽

Field Method ◽

Dark Field ◽

Bright Field ◽

Field Technique ◽

Weak Beam ◽

Partial Dislocations ◽

Enhanced Resolution ◽

Nickel Base ◽

Beam Technique

The “weak-beam” and systematic many-beam techniques are the currently available methods for resolution of closely spaced dislocations or other inhomogeneities imaged through strain contrast. The former is a dark field technique and image intensities are usually very weak. The latter is a bright field technique, but generally use of a high voltage instrument is required. In what follows a bright field method for obtaining enhanced resolution of partial dislocations at 100 KV accelerating potential will be described.A brief discussion of an application will first be given. A study of intermediate temperature creep processes in commercial nickel-base alloys strengthened by the Ll2 Ni3 Al γ precipitate has suggested that partial dislocations such as those labelled 1 and 2 in Fig. 1(a) are in reality composed of two closely spaced a/6 <112> Shockley partials. Stacking fault contrast, when present, tends to obscure resolution of the partials; thus, conditions for resolution must be chosen such that the phase shift at the fault is 0 or a multiple of 2π.

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Observation of surface morphology by reflection electron holography

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100154652 ◽

1989 ◽

Vol 47 ◽

pp. 536-537

Author(s):

N. Osakabe ◽

J. Endo ◽

T. Matsuda ◽

A. Tonomura

Keyword(s):

Phase Shift ◽

Surface Morphology ◽

High Sensitivity ◽

High Energy ◽

Path Difference ◽

Transmission Mode ◽

Electron Holography ◽

Dynamical Process ◽

High Vertical Resolution ◽

Amplification Technique

Progress in microscopy such as STM and TEM-TED has revealed surface structures in atomic dimension. REM has been used for the observation of surface dynamical process and surface morphology. Recently developed reflection electron holography, which employes REM optics to measure the phase shift of reflected electron, has been proved to be effective for the observation of surface morphology in high vertical resolution ≃ 0.01 Å.The key to the high sensitivity of the method is best shown by comparing the phase shift generation by surface topography with that in transmission mode. Difference in refractive index between vacuum and material Vo/2E≃10-4 owes the phase shift in transmission mode as shownn Fig. 1( a). While geometrical path difference is created in reflection mode( Fig. 1(b) ), which is measured interferometrically using high energy electron beam of wavelength ≃0.01 Å. Together with the phase amplification technique , the vertivcal resolution is expected to be ≤0.01 Å in an ideal case.

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