Ultrasonic atomization

Atomization is the popular name given to the first step in a spray-drying operation, viz. the division of a liquid, suspension or emulsion into fine narrow-sized droplets or particles which can quickly lose the liquid phase under appropriate physical conditions. Liquids, suspensions and emulsions are usually atomized by forcing them at high velocity through 

Dedicated portable atomization equipment has been patented [113] and an atomizer for the production of submicron, nanostructured metal powders with melting points up to 2000°C has been reported that testify to the interest of research in this area [114]. 

Although spray-drying is unusual in analytical chemistry, it is occasionally preferred to freeze-drying for sample conservation as it is faster and more economical — and also the only effective way of removing the liquid phase when the sample is fat-rich [115]. 

Morales-Muhoz, J.L. Luque-Garcia and M.D. Luque de Castro, Crit. Rev. Environ. Sci., 33 (2003) 391. 

Ultrasonic atomization is sometimes also termed capillary-wave atomization. In its most common form, 142 a thin film of a molten metal is atomized by the vibrations of the surface on which it flows. Standing waves are induced in the thin film by an oscillator that vibrates vertically to the film surface at ultrasonic frequencies. The liquid metal film is broken up at the antinodes along the surface into fine droplets once the amplitude of the capillary wave exceeds a certain value. The most-frequent diameter of the droplets generated is approximately one fourth of the wavelength of the capillary wave,1 421 and thus decreases with increasing frequency. 

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ULTRASONE Ultrasonic atomizer Ultrasonic bonding Ultrasonic devices Ultrasonic fusing Ultrasonic generators Ultrasonic instruments... 

Nondestmctive testing (qv) can iaclude any test that does not damage the plastic piece beyond its iatended use, such as visual and, ia some cases, mechanical tests. However, the term is normally used to describe x-ray, auclear source, ultrasonics, atomic emission, as well as some optical and infrared techniques for polymers. Nondestmctive testing is used to determine cracks, voids, inclusions, delamination, contamination, lack of cure, anisotropy, residual stresses, and defective bonds or welds in materials. 

Thermal treatment synthesis technique of mists formed from ultrasonic atomizer (Ultrasonic spray pyrolysis technique) Y203-Zr02, NiO, ZnS, BaTi03-SrTi03, MoS2, BiV04 [11-14]... 

Krumdieck, S. Sbaizero, O. Raj, R. 2001. Unique precursor delivery and control afforded by low-pressure pulsed-CVD process with ultrasonic atomization./. Phys. TV (Proceedings) 11 1161-1168. 

Ultrasonic Atomization Nebulizers 1-5 (55kHz, 0.12 1/min) 30-60 (50 kHz) l-200[88] Medical spray. Humidification. Spray drying. Acid etching. Printing circuit. Combustion Very fine and uniform droplets, Low spray rates Incapable of handling high liquid flow rates... 

In ultrasonic atomization, a liquid droplet is produced when powerful high frequency sound waves are focused onto the liquid. A liquid may be present in large volume and contained in a reser-... 

In an evaluation of various techniques for droplet generation,1[88] periodic vibration of liquid jet, spinning disk and ultrasonic atomization techniques have been rated as the most appropriate methods for producing monodisperse sprays. These techniques were found to be very effective and appeared promising for refinement,... 

Ultrasonic Atomization 30-50 USWA >100 Medium size distribution Solder materials, Welding electrodes, Ag-, Cu-base alloys, Dispersion-hardened allovs USWA 107 0.02-0.8 Low Spherical high quality particles, Low cost, Small unit, High EE Low volume productivity... 

Analytical and empirical correlations for droplet sizes generated by ultrasonic atomization are listed in Table 4.14 for an overview. In these correlations, Dm is the median droplet diameter, X is the wavelength of capillary waves, co0 is the operating frequency, a is the amplitude, UL0 is the liquid velocity at the nozzle exit in USWA, /Jmax is the maximum sound pressure, and Us is the speed of sound in gas. Most of the analytical correlations are derived on the basis of the capillary wave theory. Experimental observations revealed that the mean droplet size generated from thin liquid films on... 

Table 4.14. Analytical and Empirical Correlations for Droplet Sizes Generated by Ultrasonic Atomization...

Lobdell, D. D., 1968. Particle size-amplitude relations for the ultrasonic atomizer, J. Acoust. Soc. Am., 43, 229-231. 

All these microcapsules were found to be roughly spherical in shape and of similar size (14-18 pm) (Drusch, 2007). A mixture of chitosan, maltodextrin and whey protein isolate was also found to be also a good wall material for encapsulation of fish oil using an ultrasonic atomizer followed by freeze-drying of the microcapsules (Klaypradit and Huang,... 

Klaypradit, W., Huang, Y.-W. (2008). Fish oil encapsulation with chitosan using ultrasonic atomizer. LWT — Food Science and Technology, 41, 1133-1139. 

Ultrasonic atomization applied to the removal of endocrine disrupting compounds (EDCs) from an aquatic environment Sono-sorption as a new technique for removing lead ions from an aqueous solution UV disinfection of water... 

Maruyama, H., H. Seki, Y. Matsukawa, A. Suzuki, and N. Inoue. 2006. Removal of bisphenol A and diethyl phthalate from aqueous phases by ultrasonic atomization. Ind. Eng. Chem. Res. 45 6383-6386. 

Its formation is accompanied by the generation of a spray, resulting from the vibrations at the liquid surface and cavitation at the liquid-gas interface. The quantity of spray is a function of the intensity. Ultrasonic atomization is accomplished using an appropriate transducer made of PZT located at the bottom of the liquid container. A 500-1000 kHz transducer is generally adequate. The atomized spray which goes up in a column fixed to the liquid container is deposited onto a suitable solid substrate and then heat treated to obtain the film of the material concerned. The flow rate of the spray is controlled by the flow rate of air or any other gas. The liquid is heated to some extent, but its vaporization should be avoided. 

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