scholarly journals Research of the influence of acoustic load on a piezoelectric emitter to control the cavitation erosion of materials

2021 ◽  
Vol 2094 (4) ◽  
pp. 042031
Author(s):  
V N Khmelev ◽  
R V Barsukov ◽  
A R Barsukov
Keyword(s):  
Control System ◽  
High Temperatures ◽  
Electrical Impedance ◽  
Cavitation Erosion ◽  
Vibrating System ◽  
Cavitation Effect ◽  
Acoustic Load

Abstract The paper analyzes the possibilities of research the cavitation erosion of materials that are subjected to cavitation effect. The study is carried out by a system for controlling the magnitude of the acoustic load on the piezoelectric emitter of the ultrasonic vibrating system. The analysis of the processes of interaction between the ultrasonic emitter and the processed environment was carried out on the basis of a research of the model, which was created on the basis of a system of electromechanical analogies. The analysis made it possible to reveal the dependence of the electrical impedance of the ultrasonic vibrating system on the magnitude of the acoustic load. The revealed dependencies made it possible to propose and develop a control system. It is able to provide a study of the properties that are located near the emitting surface of the ultrasonic emitter of materials influenced to cavitation ultrasonic, including under abnormal conditions (high temperatures and pressures).

Control of Two-Dimensional Vibrating System

2010 ◽  
Vol 164 ◽  
pp. 333-338
Author(s):  
Jacek Kłosiński ◽  
Ludwik Majewski ◽  
Arkadiusz Trąbka
Keyword(s):  
Control System ◽  
Numerical Analysis ◽  
Angular Velocity ◽  
Vibration Frequency ◽  
Graphical Form ◽  
Two Dimensional ◽  
Unbalanced Mass ◽  
Rotary Axis ◽  
Vibrating System ◽  
Vibrating Plate

A strategy for control of a system of two electrical vibrators mounted onto the vibrating plate of a typical small table vibrator was discussed in the present paper. The aim of the considered control system is rapid positioning of counterbalances for ensuring achievement of the assumed directions of vibrations and loading forces (where , m is unbalanced mass, ω is angular velocity of the vibrator shaft, e is distance between the unbalanced mass and the vibrator rotary axis). The strategy of the control consists in setting of different directions of vibrator rotations together with controlled change of vibration frequency and amplitude. Numerical analysis was performed. The obtained results are presented in a graphical form.

scholarly journals The mechanisms of cavitation erosion of raw and sintered basalt

2019 ◽  
Vol 51 (4) ◽  
pp. 409-419 ◽  
Author(s):  
Marko Pavlovic ◽  
Marina Dojcinovic ◽  
Radica Prokic-Cvetkovic ◽  
Ljubisa Andric
Keyword(s):  
Image Analysis ◽  
Electron Microscope ◽  
Cavitation Erosion ◽  
Test Method ◽  
Cavitation Damage ◽  
G 32 ◽  
Cavitation Effect ◽  
Time Of Operation

The paper analyzes the morphology of cavitation damage of raw and sintered basalt samples. The experiment was conducted using the ultrasonic vibratory cavitation test method according to the ASTM G-32 standard. During the determination of the resistance to the effect of cavitation, a change in the mass of samples was observed in the function of the cavitation time of operation. The morphology of damage caused by the effect of cavitation was followed by scanning with an electron microscope, and the level of degradation of the surface of the samples was quantified using the image analysis. The results showed a significantly higher degree of resistance of sintered basalt, with a cavitation rate of 0.019 mg/min relative to raw basalt, with a cavitation rate of 0.738 mg/min. After 120 minutes of exposure to the cavitation effect, a smaller number of small pits on the surface of sintered basalt were observed, while a higher level of damage to the surface with the appearance of numerous pits was found in raw basalt, which can be connected in some places to larger and deeper pits in some places. The obtained results indicate the possibility of using sintered basalt for the production of parts that will be exposed to the effects of high cavitation loads.

Regenerative Systems for Vibration Control

1997 ◽  
Vol 119 (2) ◽  
pp. 208-215 ◽  
Author(s):  
M. R. Jolly ◽  
D. L. Margolis
Keyword(s):  
Control System ◽  
Vibration Control ◽  
Control Systems ◽  
Experimental Results ◽  
Active System ◽  
Average Flow ◽  
Energy Regeneration ◽  
Vibrating System ◽  
Regenerative Systems ◽  
Regenerative Vibration

The potential for energy regeneration in vibration control systems is investigated. Such control systems hold the possibility of self-sustainability by alternately extracting and releasing energy originating from the vibrating system in a controlled non-passive manner. To be self-sustaining, more energy must on average flow into the control system than flows out. Generally speaking, the performance of such a system will approach that of an active system while theoretically requiring no externally supplied power. As research progresses in this area, an increasing number of viable applications for regenerative vibration control systems are being uncovered. This paper examines two broad applications: base-excited suspensions and periodically excited compound mounts. Some experimental results of the former are presented to support our claims.

A controller for safe, convenient operation of LaB6 emitters on electron-beam instruments

1983 ◽  
Vol 41 ◽  
pp. 408-409
Author(s):  
W. J. Abramson ◽  
H. W. Estry ◽  
L. F. Allard
Keyword(s):  
Electron Beam ◽  
Control System ◽  
Thermal Shock ◽  
Appropriate Care ◽  
Electron Guns ◽  
Tungsten Filaments ◽  
Order Of Magnitude ◽  
Main Components

LaB6 emitters are becoming increasingly popular as direct replacements for tungsten filaments in the electron guns of modern electron-beam instruments. These emitters offer order of magnitude increases in beam brightness, and, with appropriate care in operation, a corresponding increase in source lifetime. They are, however, an order of magnitude more expensive, and may be easily damaged (by improper vacuum conditions and thermal shock) during saturation/desaturation operations. These operations typically require several minutes of an operator's attention, which becomes tedious and subject to error, particularly since the emitter must be cooled during sample exchanges to minimize damage from random vacuum excursions. We have designed a control system for LaBg emitters which relieves the operator of the necessity for manually controlling the emitter power, minimizes the danger of accidental improper operation, and makes the use of these emitters routine on multi-user instruments.Figure 1 is a block schematic of the main components of the control system, and Figure 2 shows the control box.

In situ REM imaging of surface processes on ceramic bulk crystals from 300 to 1670 K in a conventional TEM

1991 ◽  
Vol 49 ◽  
pp. 660-661
Author(s):  
Z. L. Wang ◽  
J. Bentley
Keyword(s):  
High Temperatures ◽  
Image Resolution ◽  
Atomic Processes ◽  
Crystal Surfaces ◽  
Beam Radiation ◽  
Surface Areas ◽  
Transmission Electron ◽  
Reflection Electron Microscopy ◽  
Gas Reactions

Studying the behavior of surfaces at high temperatures is of great importance for understanding the properties of ceramics and associated surface-gas reactions. Atomic processes occurring on bulk crystal surfaces at high temperatures can be recorded by reflection electron microscopy (REM) in a conventional transmission electron microscope (TEM) with relatively high resolution, because REM is especially sensitive to atomic-height steps.Improved REM image resolution with a FEG: Cleaved surfaces of a-alumina (012) exhibit atomic flatness with steps of height about 5 Å, determined by reference to a screw (or near screw) dislocation with a presumed Burgers vector of b = (1/3)<012> (see Fig. 1). Steps of heights less than about 0.8 Å can be clearly resolved only with a field emission gun (FEG) (Fig. 2). The small steps are formed by the surface oscillating between the closely packed O and Al stacking layers. The bands of dark contrast (Fig. 2b) are the result of beam radiation damage to surface areas initially terminated with O ions.

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