Sonic vibration

ISO 6721-9 1997 Plastics - Determination of dynamic mechanical properties - Part 9 Tensile vibration - Sonic-pulse propagation method ISO 3385 1989 Flexible cellular polymeric materials - Determination of fatigue by constant-load pounding... 

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. 

Other physical methods include air sparging, vibrations, sonication, and CO2 back-permeation. 

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

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

In addition to the deposition mechanisms themselves, methods for preliminary conditioning of aerosols may be used to increase the effectiveness of the deposition mechanisms subsequently apphed. One such conditioning method consists of imposing on the gas nigh-intensity acoustic vibrations to cause collisions and flocculation of the aerosol particles, producing large particles that can be separated by simple inertial devices such as cyclones. This process, termed sonic (or acoustic) agglomeration, has attained only hmited commercial acceptance. 

Recently, dry wire-pipe ESPs are being cleaned acoustically with sonic horns (Flynn, 1999). The horns, typically cast metal horn bells, are usually powered by compressed air, and acoustic vibration is introduced by a vibrating metal plate that periodically interrupts the airflow (AWMA, 1992). As with a rapping system, the collected particulate slides downward into the hopper. The hopper is evacuated periodically, as it becomes full. Dust is removed through a valve into a dust-handling system, such as a pneumatic conveyor, and is then disposed of in an appropriate marmer. 

Protein concentration can be determined using a method introduced by Bradford,4 which utilises Pierce reagent 23200 (Piece Chemical Company, Rockford, IL, USA) in combination with an acidic Coomassie Brilliant Blue G-250 solution to absorb at 595 nm when the reagent binds to the protein. A 20 mg/1 bovine serum albumin (Piece Chemical Company, Rockford, IL, USA) solution will be used to prepare a standard calibration curve for determination of protein concentration. The sample for analysis of SCP is initially homogenised or vibrated in a sonic system to break down the cell walls. 

Comparative tests performed on a Ro-Tap unit, a vibrating unit (Sonic Sifter — Allen-Bradley), and the Alpine Air Jet Sieve are shown in Figs 6 and 7. Fig 6 is a powdered cement Fig 7 is cadmium stearate, a waxlike material which clogs easily. These separations were all made on a 42 micron mesh sieve. These tests showed that the Alpine Jet Sieve effected good separations in a matter of minutes compared with the much longer times required for the other systems... 

In reversible polymerization, the critical concentration is equal to the equilibrium dissociation constant for polymer formation. This parameter is therefore independent of the number of polymers in solution. Confirmation comes from smdying reversible polymerization of ADP-actin when sonic vibration is applied to a solution of F-ADP-actin filaments at equilibrium with G-ADP monomers, no change is observed in the proportion of G- and F-actin (Carlier et al., 1985). Therefore, the only effect of sonic vibration is to increase the number of filaments without affecting the rates of monomer association to and dissociation from filament ends. 

When sonic vibration is applied to a solution of F-actin in the steady state in the presence of ATP, the observed behavior of F-actin is strikingly different fragmentation is accompanied by a rapid, partial depolymerizaton leading to a new steady-... 

This technique is used mainly for nonpolar compounds. Typically a small aliquot of soil (10-30 g) is dried by mixing with sodium sulfate prior to extraction. Next, the sample is extracted with a solvent for 10-20 min using a sonicator probe. The choice of solvent depends on the polarity of the parent compound. The ultrasonic power supply converts a 50/60-Hz voltage to high-frequency 20-kHz electric energy that is ultimately converted into mechanical vibrations. The vibrations are intensified by a sonic horn (probe) and thereby disrupt the soil matrix. The residues are released from soil and dissolved in the solvent. 

External vibration sources might include other equipment on bench tops, such as shakers, centrifuges, or sonicators. Local construction in the area or within the building is a common, though often overlooked, source of vibration. The testers should not be near hoods or significant airflow sources. Additionally, heavy foot traffic and door slamming should be avoided. 

MN/m2 Fixed or vibrating pintle 0.2-1 kg/kg High velocity Gas velocity sonic or above Gas-liquid ratio 0.2-1 kg/kg... 

Sonication a physical technique employing ultrasound to intensely vibrate a sample media in extracting solvent and to maximize solvent-analyte interactions. 

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). 

Horn design is a very important aspect of ultrasonic engineering. The vibrational amplitude of the piezoelectric crystal itself is normally so small that the intensity of sonication attainable by direct coupling of the transducer to the chemical system is not large enough to cause cavitation. The horn acts as an amplifier for the vibration of the transducer and the precise shape of the horn will determine the gain or mechanical amplification of the vibration. It is for this reason that it is sometimes referred to as a... 

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... 

All of the sonic disturbances in question take the form of progressive (forward moving) waves in air, in the manner of sine curves whose characteristics are governed by the laws of physics. The wave motion commences at the source of the energy release, i.e. the exploding firework, and is caused by the sequential disturbance (i.e. vibration) of the individual particles in the air. 

Hj) Height of Burst (Sonic) Test. The purpose of this test is to det the height of burst of a fuze using sonic techniques. This technique requires the measurement of the time of arrival of sound at directional microphones precisely placed in a plane. A brief description of this test is given on p IIIB-20 Ref 39 Addnl info can be obtd from "Instrumentation Section, Technical Services Laboratory, Ammunition Development Division, Ammunition Engineering Directorate, Picatinny Arsenal, Dover, NJ 07801 H2) Hydraulic Ram and Vibrator Test. This test could be used to simulate impact shock on bombs or rockets assembled with fuzes that are launched from aircraft. It also could check the transportability of fuzes that experience this environment. This test is listed, but not described in Ref 39, p IIB-37... 

The bandwidth is the range of frequencies over which a sonic transducer will vibrate... 

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