Aerosol-generated droplets

The droplet size delivered from a vibrating orifice monodisperse aerosol generator can be derived from the following expressions ... 

Aerosols generated by nebulization are directed through a spray chamber, which is usually constructed from glass, or an inert polymer (Fig. 4.9) The spray chamber prevents larger aerosol droplets from reaching the plasma, as... 

Fig. 1.5.3 Aerosol generator assembly for the production of composite or coated particles (a) carrier gas (e.g., helium) tank, (b) drying column containing silica gel and molecular sieve, (c) Millipore membrane of 0.1 p.m pore size, (d) flow meters, (e) nuclei (e.g., NaCI, AgCI) generator, (f) and (m) boilers containing different reactant liquids, (g) and (n) condensation chambers, (h) heater, (i) chamber for recondensation of droplets, (q) and (e) coreactant containers, (k) and (p) vapor injection ports, (I) and (g) reaction chambers, (r) powder collector. (From Ref. 39.)...

Experimental evaluation of various widely used commercial instruments has been undertaken by several investigators, including Liu et al. (1974), who used the vibrating orifice technique to generate spherical aerosols with narrow size distributions. Similarly, Pinnick and Auvermann (1979) generated droplets of a solution which were dried to make solid particles for evaluating the response of... 

DOP polydisperse aerosol generated by blowing air through liquid dioctyl phthalate (DOP) at room temperature. The approximate light-scattering mean droplet size distribution of the aerosol is ... 

Pneumatic nebulizers are utilized for the generation of an aerosol with droplet size distribution in the low pm range3 and consequently for an effective solution introduction into the ICP ion source... 

Experimental methods presented in the literature may prove of value in combustion studies of both solid and liquid suspensions. Such suspensions include the common liquid spray. Uniform droplets can be produced by aerosol generators, spinning disks, vibrating capillary tubes, and other techniques. Mechanical, physicochemical, optical, and electrical means are available for determination of droplet size and distribution. The size distribution, aggregation, and electrical properties of suspended particles are discussed as well as their flow and metering characteristics. The study of continuous fuel sprays includes both analytical and experimental procedures. Rayleigh s work on liquid jet breakup is reviewed and its subsequent verification and limitations are shown. 

An aerosol generated by nebulization is directed through a spray chamber (nebulizer chamber). This is usually made of glass, quartz, or inert polymers (Ryton or several fluorine-based polymers), which prevents large aerosol droplets from reaching the plasma. The classical Scott chamber design has been superseded by the cyclonic chamber, which has a 50% better sensitivity. 

There are many commercially available nebulizers with differing mass output rates and aerosol size distributions which will be a function of operating conditions, such as compressed air flow rate. As described above, for maximum efficacy, the drug-loaded droplets need to be less than 5 pm. In the treatment or prophylaxis of P.carinii pneumonia with nebulized pentamidine where the target is the alveolar space it is preferable to use nebulizers capable of generating droplets of less than 2 pm. 

Aerosol generators and loggers convert special formulations into very small, fine droplets. Single droplets cannot be seen, but large numbers of droplets are visible as a fog or mist. Aerosol generators and loggers are usually used to completely fill a space with a pesticidal fog. Some insects in the treated area are killed when they come in contact with the poisai. Other insects are simply repelled by the mist and return quickly after it has settled. 

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