Sonic and ultrasonic vibrations

Physical forces photo energy (particularly IR and UV), subsonic, sonic, and ultrasonic vibrations and moisture changes. 

Vibration Method. Vibration techniques were first used in determining the adhesion of films. Later, Larsen [81] determined the force of adhesion of spherical particles to fibers vibrating at a frequency in the range of 10-90 Hz. This method was improved and extended by the use of sonic and ultrasonic vibration [14]. 

More efficient methods for removing adherent dust include the following intermittent blowback at rather high air velocities (pulsating, impulse, etc) with simultaneous breakup of the dust layer mechanical shaking (impact, vibration, pulse, etc.) the use of sonic and ultrasonic vibration filter washing. 

Vibration-dampening properties at sonic and ultrasonic frequencies are excellent. However, the thickness of the resin must be sufficient to absorb... 

Ultrasonic extraction, also known as sonication, uses ultrasonic vibration to ensure intimate contact between the sample and the solvent. Sonication is relatively fast, but the extraction efficiency is not as high as some of the other techniques. Also, it has been reported that ultrasonic irradiation may lead to the decomposition of some organophosphorus compounds [12]. 

Vibration or modal analysis yield indications of defects in structural elements or parts when excited by suitable loads (37) (also see Sonic and Ultrasonic Test Methods). The literature mainly describes applications to PMC laminates, aiming at detecting critical delaminations (38). A relative comparison for a specific element with time, loading, or exposure may be sufficient to find indications of a defect or of a change in the behavior of the structure. Comparison with finite element calculations is one approach for quantitative evaluation (39). Recent research on monitoring of PMC elements or structures also investigates the use of piezoelectric sensors for detection of delaminations by external excitation (40). 

A comparison has been made of the efficiencies of conventional and ultrasonically assisted pollutant extraction procedures using model soil samples (granular pieces of brick) which had been deliberately contaminated with copper oxide at 51 ppm [50]. Analysis of the brick particles after 30 min sonication on a Vibrating Tray [51] revealed an average reduction in copper content to 31 ppm, a reduction of about 40%. Using a conventional mechanically shaken tray for the same time period the residual contamination was 48 ppm representing a reduction of only 6% (Tab. 4.6). 

If transducers are fixed to the external surface of a tube then the tube itself becomes the source of ultrasonic energy. The liquid to be processed can then be passed through the tube and receive sonication directly from the ultrasonically vibrating walls. Two design engineering problems are associated with this type of sonicator (1) the correct mounting of the transducers on the outer tube and (2) the length of the tube must be... 

When water is added to certain dry phospholipids with long hydrocarbon chains, the phospholipids swell, and when they are dispersed in more water, structures known as liposomes are formed. Liposomes are vesicles with multilayers of phospholipid. See Fig. 6-5. When subjected to ultrasonic vibration (sonication), liposomes are transformed into vesicles that have only a single bilayer of phospholipid. 

The colloid vibration potential (difference) E or CVP is the a.c. potential difference measured between two Identical relaxed electrodes, placed in the dispersion if the latter Is subjected to an (ultra)sonlc field. CVP Is a particular case of the more general phenomenon, ultrasonic vibration potential (UVP), applying to any system, whether or not colloids are present. This field sets the particles into a vibrating motion, as a result of which the centres of particle charge and countercharge are periodically displaced with respect to each other. This phenomenon is the a.c. equivalent of that observed in the Dorn effect. Counterpart to this is the electrokinetic sonic amplitude, ESA, the amplitude of the (ultra)sonlc field created by an a.c, electric field in a dispersion. 

The kinetic potential is usually denoted as the zeta (0 potential and it is determined from the electrophoretic mobility of the extremely dilute particles in an electric field. More recently, the nse of electrokinetic sonic amplitude (ESA), acoustosizer (AZR), or colloid (or ultrasonic) vibration potential (CVP) has become available for the determination of the potential in rather concentrated particle suspensions. Again the potential may be measured as a function of either the metal concentration or the pH. In the latter case the point where the mobility ceases is denoted the isoelectric point (pH,Ep Fignre 8.27). It correlates particnlarly well with the stability of the sol. 

Other treatments in vitro that have been found to alter the electrophoretic migration of cholinesterase include ultrasonic vibration and the addition of urea. By such means, the major component of the enzyme produces enzymically active bands which have the respective mobilities of each of the other isoenzymes (A29, D25). Dubbs (D25) has suggested that sonication might release enzyme which was previously bound to /3-lipoprotein, rather than convert one isoenzyme into another. 

The use of impinging jets or sonic or ultrasonic or ultra types of vibration characteristics and the dispersion in the nano- and attotechnology rates are a popular and important topic in current research. There is not a comprehensive technical background for the design of these devices. Since the requirements of many types of dispersion are not quantitatively available before trial, considerable work on small-scale operations is required. However, the atto- and nanotechnology area is already a small-scale one the device that will be the ultimate choice in the plant will be used in an actual experiment on the actual scale, sometimes. 

Ultrasonication is another liquid-shear method of cell disruption. Ultrasonic vibrations having frequencies greater than 18 kHz are able to disrupt microbial cells in suspension. The ultrasonic vibration could be emitted continuously or in the form of short pulses. A frequency of 25 kHz is commonly used for cell disruption. The duration of this procedure depends on the cell type, the sample size and the cell concentration. The transmission of sonic waves creates a continuous cycle of microbubble cavitation in the suspending medium. These cavities or small bubbles of dissolved gases or... 

Sonogel Gel obtained when the mixing of the precursor, solvent, and water is enhanced by ultrasonic vibrations (sonication)... 

Figure 5.17 Principle of acoustophorcsis. Concerning the UVP (Ultrasonic Vibration Potential - top), an ultrasonic wave applied on a liquid (transducer) induces solvent motion. As the two charged species have a different masses and frictional coefficients, its move differently. The charge heterogeneonsness which appeared in this way generate a macrr opic and thus measurable electric field (electrodes). Concerning the ESA (Electro Sonic Amplitude - bottom), an alternative electric field is applied (electrodes). Eachs ion species moves in opposite direction. This motion induces a detectable ultrasonic wave (transducer).

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