Sample sampler

Settling plate, M air T air sampler, or slit sampling sampler are used for class 100, level I. Use operating procedure per plant SOP. RCS + (Biotest Hycon) air sampler is used for other classes. A specified sampler shall be used only for class 100 areas. 

To avoid contamination of seawater with trace elements during sampling, samplers should meet the following conditions ... 

The evaluation of the deconvolution results show that time resolution is better or equal to 1 with the chosen processing time unit of 0.08 microseconds (respectively a rate of 12.5 MHz). First signals processed conservatively have been acquired with a samplerate of 12.5 MHz. A Fourier analysis shows that the signals spectras do not have energy above 2.0 MHz. This means that a sampling rate of 4.0 MHz would have done the job as well. Due to the time base of the ADC an experimental check with a sample rate of 5.25 MHz has been carried out successfully. 

Samples from municipal wastewater treatment plants and samples of industrial discharges often are collected as 24-h composites. Samples are obtained using an automatic sampler that periodically removes individual grab samples. The volume of each sample increment and the frequency of sampling may be constant or may vary in response to changes in flow rate. 

Sediments from the bottom of streams, rivers, lakes, estuaries, and oceans are collected with a bottom grab sampler or with a corer. Grab samplers are equipped with a pair of jaws that close when they contact the sediment, scooping up sediment in the process (Figure 7.5). Their principal advantages are ease of use and the ability to collect a large sample. 

Disadvantages include the tendency to lose finer-grained sediment particles as water flows out of the sampler and the loss of spatial information, both laterally and with depth, due to mixing of the sample. 

Total airborne particulates are determined using a high-volume air sampler equipped with either cellulose fiber or glass fiber filters. Samples taken from urban environments require approximately 1 h of sampling time, but samples from rural environments require substantially longer times. 

The end or front of the plasma flame impinges onto a metal plate (the cone or sampler or sampling cone), which has a small hole in its center (Figure 14.2). The region on the other side of the cone from the flame is under vacuum, so the ions and neutrals passing from the atmospheric-pressure hot flame into a vacuum space are accelerated to supersonic speeds and cooled as rapid expansion occurs. A supersonic jet of gas passes toward a second metal plate (the skimmer) containing a hole smaller than the one in the sampler, where ions pass into the mass analyzer. The sampler and skimmer form an interface between the plasma flame and the mass analyzer. A light... 

Sampling of Particulates. Ambient air suspended particulate concentration was traditionaUy measured gravimetricaUy over a 24-h period with a "Hi-Vol" sampler. However, in 1987 the EPA changed ambient particulate control to the PM q reference method (24). In the PM q method, a... 

It is often important to quantify the contamination of pore fluid in the unsaturated soil 2one, where monitoring wells are ineffective. In this region, suction cup lysimeters are useful (7). These samplers consist of a porous cup, typically ceramic, having two access tubes which are usually Teflon. One access tube provides a pressure-vacuum, the other discharges the sampled fluid to the surface. The porous cup, typically between 2 and 5 cm in diameter, is attached to a PVC sample accumulation chamber. 

Proximity to Breathing Zone. Whereas all exposure measurement methods attempt to sample from air that is likely to be inhaled, some methods do so better than others. A sampler fixed some distance away from a breathing area is not usually accurate in measuring exposure. Even using mobile samplers that move with the worker, the few centimeters in distance from the nose and mouth to the position of the sampler, has been found to make a difference. 

Eor toxic materials, it usually is advisable to provide ventilated sampling hoods or breathing-air stations and masks, to assure that the sampler is adequately protected from toxic or flammable vapors and dusts. Special provision for access to and exit from sampling points also may be needed at elevated locations and to avoid tripping or bumping ha2ards and to ensure that the sampler does not transverse areas not intended as walkways, eg, tank covers or roofs. 

If the standard deviation of the lot caimot be estimated, a sampling program of greater sample size is required to generate an estimate of the standard deviation for future sampling operations. In some cases, sample size can be increased and sampling costs reduced by the use of automatic samplers. These offer a substantial reduction in labor costs but an increase in capital costs. 

Air—electric samplers can be installed directly in the pipe wall. One type of Hquid sampler is operated by a solenoid valve that activates an air cylinder. A shaft is moved in and out of the pipe by this cylinder and samples are expeUed into a container below the sampler. Sample volumes of from 2—30 mL are possible. 

For low pressure pipelines that have ports open to the atmosphere, eg, sewers or closed effluent culverts, samplers are designed to sample through manholes. In a typical system, the Hquid is lifted through a suction line into the sampling chamber under vacuum. When filled, the vacuum shuts off, and the sample drains into a sample jar. A secondary float prevents any Hquid from reaching the vacuum pump. The suction line then drains by gravity back to the source. 

A more permanent installation is provided by a chain-driven sampler, widely used in paper (qv) and steel (qv) mills, manufactured as the E Sampler by QCEC (20). A cup, which is attached to a chain positioned perpendicular to flow, travels down through the Hquid flow and returns to the upper sprocket, where the sample is drained into a container. Flow-proportional timers can be installed to change the rate of sampling with flow rate (see Flow l asurel nt). 

Cutter-type samplers can be installed for low pressure pipelines and enclosed troughs. These samplers contain a movable cutter coimected to a flexible hose through which the sample is extracted. Such devices meet all three rules for good sampling they sample a moving stream, the sample is made... 

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