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Modern particulate samplers use a volumetric flow control system that pulls air through the particle separator at the velocity required to achieve the desired cutpoint. For air pollution applications, the definition of "particulate" does not include uncombined water , and water from a particulate sample must be removed before it is weighed.
A sampler is an electronic musical instrument that records and plays back samples (portions of sound recordings). Samples may comprise elements such as rhythm, melody, speech, sound effects or longer portions of music. The mid-20th century saw the introduction of keyboard instruments that played sounds recorded on tape, such as the Mellotron.
An impactor is a device that classifies particles present in a sample of air or gas into known size ranges. It does this by drawing the air sample through a cascade of progressively finer nozzles. The air jets from these nozzles impact on plane sampling surfaces and each stage collects finer particles than its predecessor.
The speed of sound is the distance travelled per unit of time by a sound wave as it propagates through an elastic medium. More simply, the speed of sound is how fast vibrations travel. At 20 °C (68 °F), the speed of sound in air, is about 343 m/s (1,125 ft/s; 1,235 km/h; 767 mph; 667 kn), or 1 km in 2.91 s or one mile in 4.69 s.
Physicists have found that observation of quantum phenomena by a detector or an instrument can change the measured results of this experiment. Despite the "observer effect" in the double-slit experiment being caused by the presence of an electronic detector, the experiment's results have been interpreted by some to suggest that a conscious mind ...
Andersen's schematic for the six-stage Andersen sampler, detailing movement of air and hole sizes for the top two stages [1]. An Andersen sampler, Andersen impactor, or sieve impactor [2] is a cascade impactor used to determine the amount of viable pathogens in a given area, in particular bacteria and fungi.
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Beta attenuation monitoring (BAM) is an air monitoring technique employing the absorption of beta radiation by solid particles extracted from air flow. The technique allows for the detection of PM 10 and PM 2.5 , which are monitored by most air pollution regulatory agencies.