Collection techniques

The collection technique involves the removal of particles from the air stream. The two principal methods are filtration and impaction. Filtrahon consists of collecting particles on a filter surface by three processes—direct interception, inertial impaction, and diffusion (5). Filtration attempts to remove a very high percentage of the mass and number of particles by these three processes. Any size classification is done by a preclassifier, such as an impactor, before the particle stream reaches the surface of the filter. 

Water sample collection techniques differ depending on the source being tested. The minimum number of water samples collected from a distribution system which are examined each month for coliforms is a function of the population. For example, the minimum number required for populations of 1,000 and 100,000 are 2 and 100, respectively. To ascertain compliance with the bacteriological requirements of drinking water standards, a certain number of positive tests must not be exceeded. When 10-ml standard portions are examined, not more than 10 percent in any month should be positive (that is, the upper limit of coliform density is an average of one per 100 ml). 

A range of other data collection techniques are used in conjunction with process simulation such as interviews, the verbal protocols described earlier, walk-throughs and questionnaires. An appropriate analysis of the task is necessary in order to determine the nature of the simulation to be used. An... 

In order to identify the major factors affecting the decision to resort to blowdown and the execution process of this operation, a number of data collection techniques were utilized, as shown in Table 7.1. 

TABLE 7.1 Data Collection Techniques in the Human Factors Audit ... 

Mass spectrometer-target collection technique, measurement of... 

Target collection technique, mass spectrometer, and measurement... 

P. C. H. Miller, P. J. Walklate, and C. J. Mawer, A comparison of spray drift collection techniques, in Proceedings of British Crop Protection Council Brighton Conference on Weeds , British Crop Protection Council, Farnham, pp. 669-676 (1989). 

Multiple-collection techniques. Uranium. Table 1 shows a typical protocol used by multi-collector instruments (equipped with one ion counting channel) both in MC-TIMS, MC-ICPMS and LA-MC-ICPMS (e.g., Cohen et al. 1992 Stirling et al. 1995 Luo et al. 1997 Stirling et al. 2000 Pietruszka et al. 2002). A first sequence monitors the atomic ratios between and by aligning Faraday collectors for masses (10 ... 

The gravity and baffle chambers provide the simplest of gas collection techniques. The gas is allowed to travel through a large chamber or a long tunnel to reduce its velocity, causing the dust to drop out by the action of gravity. The gas flow is deflected by baffles, or the flow direction may be reversed in order to enhance the separation. 

As in most of the separation methods, the stripping and collection techniques have not been investigated for their recovery efficiences except in isolated instances. Kuo et al. [50] have found recovery efficiences for volatile polar organics ranging from 9.5% for ethanol to 88.8% for acetone. Most of the model compounds displayed recovery efficiencies in the 60 - 80% region under the conditions of their experiment. 

Time-Resolved Crystallography. Time-resolved crystallography (TC) uses an intense synchrotron X-ray source and Laue data collection techniques to greatly reduce crystallographic exposure times. Normal time resolution for X-ray... 

Collection Techniques. The simplest mechanical method for normal liquid droplets is the slide collection slide sampling) or impression method. This method was extensively used three decades ago, and has been rarely employed since then. In this method, when the slide is exposed to a spray, droplets impinging on it make impressions. The impressions are then observed and measured usually using a Quantimet image analyzer, although a microscope fitted with a traversing scale may be used for the measurement. The measured data are subsequently converted to actual droplet sizes based on a correction factor proposed by May.[659]... 

Blood and Urine Collection. About 5-10 ml of blood can be collected from adult ferrets using retroorbital blood collection techniques. Other methods of blood... 

Results Most of the process-related, nonagent compounds present in the GPCR product gas are measured using a bubbler and standard EPA collection techniques. The process-related, nonagent compounds for which a method was not developed included vinyl sulfide, mercaptans, dimethylamine, and ethanethiol. 

The urine collecting techniques (Fig. 1), were revised from those used by other investigators at Mt. Desert Island Biological Laboratory, Salsbury Cove, ME. Female fish weighing from 3-7 kg were prepared by ligating one end of a 10 cm length of P.E. 190... 

A first approach to determining explosives on-site might include a combination of specialized sample-collection techniques and subsequent analysis using established IMS technologies or instruments. A second level of development could involve the fabrication of analyzers or analytical systems for an on-site operation and real-time analysis of samples. During the past several years, the first step of development has been demonstrated for explosives in water, in soils, and in a few unique uses. 

Laboratory safety data can be erroneous, and this must always be considered when abnormalities are reported. There are numerous sources of error, which may be related to the study subject (e.g. self-medication, certain foods, undue exercise), sample collection technique, storage and transport, the analytical technique used... 

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