Droplet delivery generator

A limited number of empirical correlations have been developed for metal droplet sizes generated by water atomization, as listed in Table 4.18. In these correlations p is a system-specific constant, is the atomizing angle, i.e., angle between water nozzle axis and metal delivery nozzle axis, A is a proportional constant specific to atomizer type, melt type and melt temperature, n is a parameter depending on atomizer type, APw is the water pressure, Uw is the water velocity, and mw is the mass flow rate of water. 

Recently, EWOD actuation chips were developed into a multiplexed device that was used to simultaneously cleanup four samples. A sequence of seven actuation steps were performed for each sample (1) generation of sample droplets (0.02 p.L), (2) transport and drying of sample droplets, (3) generation of rinsing droplets, (4) transport of rinsing droplets to the sample sites for selective dissolution of urea, (5) transport and disposal of the rinsing droplets, (6) generation of MALDI matrix solution droplets, and (7) delivery of matrix droplets to the dried peptide spots. 

Scale-up of gas atomizers is difficult and it requires the use of higher gas-to-melt mass flow rate ratio to maintain the same droplet size. The scale-up may also cause some complex phenomena to occur, such as the disappearance of the prefilming effect in close-coupled atomizers, the generation of turbulence in melt flow within delivery nozzle, and change in atomization mechanisms. 

Fig. 3 Spotting tools for non-contact printing a Bubble ink-jet A heating coil locally heats the loaded sample, resulting in a changed viscosity and expansion of fluids. The generated droplet can be easily expelled from delivery nozzles, b Microsolenoid A microsolenoid valve, fitted with the ink-jet nozzle is actuated by an electric pulse transiently opening the channel and dispenses a defined volume of the pressurized sample, c Piezo ink-jet A piezoelectric transducer that is fitted around a flexible capillary confers the piezoelectric effect based on deformation of a ceramic crystal by an electric pulse. An electric pulse to the transducer generates a transient pressure wave inside the capillary, resulting in expulsion of a small volume of sample...

Fine water spray systems may be potentially superior to CO2 applications and may replace halon environments such as telephone central offices and computer rooms. In the fine spray delivery system, water is delivered at relatively high pressure (above 100 psi [0.689 MPa]) or by air atomization to generate droplets significantly smaller than those generated by sprinklers. Water flow from a fine spray nozzle potentimly extinguishes the fire faster than a sprinkler because the droplets are smaller and vaporize more quickly. Preliminary information indicates that the smaller the droplet size, the lower the water flow requirements and the less chance of water damage. 

Tang, K. Gomez, A. Generation by electrospray of monodisperse water droplets for targeted drug delivery by inhalation. J. Aerosol Sci. 1994, 25 (6), 1237-1249. 

Nebilizers are among the oldest devices used for delivery of therapeutic agents.18 They employ energy from compressed gas or piezoelectric ceramics to generate droplets of water containing dmg. The principle of air jet dispersion is shown in Figure 16.1C. Dmg solution (or occasionally suspension) is drawn from a reservoir... 

Kim S, Song Y, Skipper P, Han J (2006) Electrohydrodynamic generation and delivery of monodisperse picoliter droplets using a poly (dimethylsiloxane) microchip. Anal Chem 78(23) 8011-8019... 

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