Sonic drying

On a microscale, sound is characterized by pressure and particle velocity. The product of these two parameters is called sound intensity—a vector quantity that describes the rate of energy flow through a imit surface area normal to the direction of sound propagation 

Force Distance Energy Power (131) Area Time Area x Time Area 

On a macroscale, sound is primarily characterized by the frequency (/), which relates the speed of wave propagation ( ) (sound velocity) to the wavelength (X)  

The second main quantity used to characterize sound on a macroscale is the amplitude of the pressure fluctuations expressed as the sound pressure level (SPL) on the decibel (dB) scale with 20 Pa as reference level. Because the sound pressure depends on the distance from the source generating given sound power (energy per unit time) and on the acoustic environment (sound 

In a free acoustic field such as that in an open air or anechoic chamber, the pressure and intensity levels in the direction of propagation are numerically the same. In a diffuse field in which sound is reflected so many times that it travels in all directions with equal magnitude and probability (reverberation chamber), the pressure and intensity levels are different and this difference is known as the pressure-intensity index (phase index or reactivity index). 

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Since only exploratory studies have been reported so far on sonic drying, the following discussion of the drying mechanism focuses on the ultrasonic applications, which have been of research interest for years. Definitely, some of these mechanisms may also contribute to sound and infrasound drying. In these cases, postulation of a particular mechanism requires, however, further studies. 

Under real drying conditions heat generated within the material volume is transported away by conduction and convection so the final temperature tends to equilibrium determined by the heat balance. The equilibrium temperature for the bulk of the material is the order of few degrees (Zayas and Pento, 1975 Strumillo and Kudra, 1989 Brun and Boucher, 1957), which justifies moisture evaporation due to thermal effects of sound irradiation to be neglected. This obviously favors sonic drying as a method for processing heat-sensitive materials. 

Fig. 6. Dry-siever employing sonic frequency (a) particles falling through sieves on downward sonic pulse and (b) particles lifted by upward sonic pulse.

Composition and Methods of Manufacture. Vaccine is produced from the Oka attenuated strain. Vacciae is produced in human diploid cells such as MRC-5. After growth in the cell substrate, the cells themselves are harvested into the growth medium and sonicated to release the cell-associated vims. Sucrose and buffering salts are generally in the medium to help stabiLize the vims. The vacciae is presented in a free2e-dried vial to be reconstituted with sterile distilled water before injection (27). 

In the procedure for the surface test (313), the vims is grown in a monolayer of baby hamster kidney cells and incubated in Eagles medium supplemented with tryptose phosphate broth and calf semm. After separation of the vims from the cells by sonification and centrifugation, amounts of the suspension containing 3 x 10 plaque-forrning units are dried on coversHps. The inoculated coversHps are placed in 5 ml of the disinfectant for 1, 5, or 10 min, then rinsed, sonicated, and assayed. 

Other types are available that use sonic energy (from gas streams), ultrasonic energy (electronic), and electrostatic energy, but they are less commonly used in process industries. See Table 14-11 for a sum-maiy of the advantages/disadvantages of the different type units. An expanded discussion is given by Masters [Spray Drying Handbook, Wiley, New York, (1991)]. 

Micromesh Sieving machines (Air jet, sonic wet and dry) Biickbee Mears, Veco, Endecottes Alpine, ATM, Gilson, Gradex, Hosokawa, Retsch, Seishin 5-500 -1- im 1-5... 

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. 

Residual dinitroaniline herbicides are generally extracted from 10-25 g of air-dried soil samples using organic solvents such as ethyl acetate, acetonitrile, methylene chloride and acetone by sonication, mechanical shaking or Soxhlet extraction. If necessary, the extract is then cleaned by a Florisil column or SPE. The extract is allowed to evaporate completely to dryness and the residue is dissolved in an appropriate volume of the solvent for GC or HPLC analysis. 

For a soil sample, weigh 30 g (dry soil) of the sample into a 300-mL Erlenmeyer Aask and add 150 mL of water-acetoniAile (1 9, v/v). Sonicate the mixture for 30 min. Filter the exAact through a Alter paper overlaid with 20 g of Celite in a Buchner funnel into a 1-L round-bottom Aask with suction. Rinse the beaker and the Alter cake twice with 50 mL of acetoniAile. Combine the AlAates and concenAate to approximately... 

For soil, after concentrating the dichloromethane, dissolve the dry residue in 1 mL of ethyl acetate and dilute the solution with 2 mL of hexane. Sonicate the contents of the flask for approximately 15 s to remove any residue remaining on the walls of the round-bottom flask. Proceed to Section 6.2.3. 

Reconstitute the dry plant residue from Section 6.2.1 in 50 mL of hexane saturated with acetonitrile and transfer the flask contents to a 250-mL separatory funnel. Rinse the round-bottom flask with 50 mL of acetonitrile saturated with hexane and add this rinse to the hexane in the separatory funnel. Partition the residue from the hexane into the acetonitrile. Drain the acetonitrile into the 500-mL flask from the dichloromethane partition step (Section 6.2.1). Re-extract the remaining hexane phase with an additional 50 mL of acetonitrile saturated with hexane. Combine the acetonitrile fraction with the acetonitrile from the first partition. Concentrate the combined acetonitrile fractions to dryness in a rotary evaporator at <40 °C. Dissolve the dry residue in 1 mL of ethyl acetate and dilute the sample with 2mL of hexane. Sonicate the sample for... 

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. 

Weigh 30 g (dry soil base) of soil into a 300-mL round-bottom flask, add 90 mL of acetonitrile and 30 mL of water, shake the mixture for 10 min and sonicate it for 30 min. Filter the mixture through a Alter paper on a Buchner funnel by suction and collect the filtrate in a 500-mL round-bottom flask. Wash the beaker and the residue with 60 mL of acetone and filter the washings. Combine and concentrate the filtrates to 20 mL at 50 °C or lower under reduced pressure. 

Several precautions were taken to ensure the immobilization chemistry. First, the sulfhydryl groups containing the macromolecular fraction was spectrophotometrically determined according to the literature [15]. We found that every set of 150 base pairs contained approximately one disulfide group. Since the DNA fragment used has hundreds of base pairs, each DNA strand seems to have one disulfide as its terminal group. Next, we made IR spectral measurements in a reflection-absorption (RA) mode [14b]. A freshly evaporated gold substrate was immersed into the DNA solution for 24 h at 5°C. The substrate was carefully rinsed with deionized water, dried under vacuum and was immediately used for the measurements. An Au substrate treated with unmodified, native sonicated CT DNA solution was also prepared as the control measurement. The / -polar-ized radiation was introduced on the sample at 85° off the surface normal and data were collected at a spectral resolution of 4 cm with 2025 scans. 

Thin-fdm was prepared from a slurry of catalyst powder which was prepared from 10 mg catalyst in 5 ml of 2-propanol. The catalyst slurry was sonicated for 30 min. and allowed to sit stagnant overnight. Before preparing the films, the slurry was sonicated for 15 min., 20 drops (0.1 ml) were added onto a ZnSe trough plate internal reflection element (022-2010-45, Pike Technologies). The solvent was allowed to evaporate, the procedure was repeated a total of five times. After drying in air at room temperature, the catalyst thin-film was ready for 2-propanol dehydrogenation studies. 

For the DRIFTS study, the Nafion-Ti02 slurries were sonicated for 2 hours, dried at ambient conditions for 5 hr, and ground with a pestle and mortar until a fine powder catalyst was formed. 30 mg of the resulting catalysts were placed on top of 80 mg of inert CaF2 powder (325 mesh, Alfa Aesar) in a DRIFTS cell s sample holder. The sample holder was enclosed by a dome with two IR transparent ZnSe windows and a third CaF2 window for UV illumination. For the ATR study, the Nafion-Ti02 slurries, which were sonicated for two hours, were cast directly on the surface of the ATR ZnSe crystal to form a continuous solid film. The films were enclosed with a stainless steel cover equipped with a CaF2 window for UV illumination. 

Phenylmethyldichlorosilane (Petrarch) was distilled prior to use and dried over CaH2- Toluene was distilled from CaH2 and dried over CaH2- The known amounts of sodium were placed in a flask filled with toluene and purged with dry argon. This flask was placed in the ultrasonic bath (75-1970 Ultramet II Sonic Cleaner, Buehler Ltd.) until stable dispersion of sodium was formed. In some experiments an immersion-type ultrasonic... 

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