Wednesday, September 18, 2019
Particle Kinetics of Biological Aerosols During Impaction Essay
At the beginning of the 20th century, the study of aerosols, suspensions of solid or liquid particles in a gas, were the forefront of physical science because they represented the smallest observable division of matter. In fact, aerosols contributed to the early understanding of Brownian motion and diffusion, Millikan's measurement of electron charge, and Wilson's cloud chamber experiment for the study of ionizing radiation. During the first half of the century, aerosol research continued, and grew important after World War II and especially during the 1970s and 1980s, during which environmental awareness and a concern for health effects arising from air pollution in community and occupational environments, promoting the development of aerosol technology. The field expanded rapidly in the 1980s, including the involvement of aerosols in high technology production processes and a concern for aerosol contamination. The decade of the 1990s has seen increased research on the properties of ultra fine particles and on the effect of aerosols on global climate. Now, aerosol technology has become an important toll in understanding the effect we have on our environment and the impact of the environment on us. After all, there are multiple aerosols in our own surroundings, such as re-suspended soil particles, smoke from power generation, photochemically formed particles, salt particles created from ocean spray, and the water droplets or ice particles that form clouds, and include a wide range of phenomena such as fume, dust, smoke. Every aerosol varies in their ability to affect visibility as well as our health and quality of life, and understanding the properties of aerosols would enable us to comprehend so many natural processes, such as cl... ...DRUMs like the one displayed below, coating the surface with the sticky covering of your choice, and using a motor to rotate the DRUM, as the particles are drawn in by the vacuum, they are deposited onto the plate, and the plate rotates continuously, preventing the build-up of particles in one area. The dynamics of particle deposition on the circular DRUM are essentially the same as that of the impactor plate, because the width of the nozzle is so tiny compared to the surface area of the curved DRUM, that, despite the curve, in relation to the nozzle, the DRUM is essentially a flat surface. References * Reist, Parker C. Aerosol Science & Technology: Second Edition. New York: Macmillan, Inc, 1984. * Hinds, William C. Aerosol Technology: Properties, Behavior, & Measurement of Airborne Particles, Second Edition. New York: John Wiley & Sons, Inc, 1999.