Filter configurations

To cross the filter, the solute must diffuse through the filter pores. Therefore, pore size, density, and tortuosity must be taken into consideration. Many filter configurations are commercially available and have been employed for these types of studies. In general, the greater the pore size and porosity, the less the potential for the filter to act as a significant diffusion barrier. For small solutes, the filter will probably not present much of a problem. However, as the molecular size of the solute increases and approaches the dimension of the pore, these considerations become more important. In principle, solute diffusion through the... 

Dust samples were collected by the probe/filter configuration shown in Figure 2. The filter used to trap the explosive dust was a 37mm plastic filter cassette. To monitor the actual flow rate, a rotometer was used. The calculation for each traverse point dust concentration was obtained from... 

APOPO uses a polyester fiber wad for their rats to smell so we ran a parallel adsorption filter configuration (Fig. 8.3) and let the rats smell both the MEDDS and the APOPO filter. Figure 8.3 is a picture of the parallel filter system. 

The dual-channel (reference filter) configuration is shown in Fig. 8. The reference filter and the sample filter, which define the spectral region of interest, are mounted on a spinning chopper wheel. As the chopper spins, it alternately positions the filters in the optical path. The signal is demodulated in a similar manner to the dual-beam approach. In order for ihe reference... 

The suspensions are centrifuged and washed twice in 3% FBS/PBS. They are again centrifuged and washed twice in 3% FBS in PBS with 0.1% Triton X-100. The pellets are resuspended and incubated with 0.5 ml of 1% FBS containing propidium iodide (10 pg/ml Calbiochem, San Diego, CA) and RNAse (1 mg/ml) in Hank s balanced salt solution (without phenol red) for 30 min at 37°C. The samples are analyzed on a Coulter Electronics XL-MCL or a Becton Dickinson FACScan flow cytometer with standard argon ion laser excitation and filter configuration for the FTTC/propidium iodide dye combination. 

Figure 10 shows simulations of different energy filter configurations. In Fig. 10a the filter ends at the focal point which is exactly in the center of the outlet aperture. Hence a small outlet aperture is sufficient and a high selectivity is expected. If the filter is extended to 90 °, as it is usually the case in macroscopic systems (Fig. 10b)... 

Confocal microscope system with argon-laser line at 488 nm and helium-neon-laser lines at 543 and 633 nm and appropriate filter configurations, such as the Leica SP2 or Zeiss Pascal Axioplan LSM. 

FIGURE 18.14 Typical depth filter housing arrangement and a pleated depth filter configuration. 

There are many filter configurations within the industry, such as sheet or modular depth filter types for prefiltration purposes, flat filter membranes mainly for microbial detection and, specifications, and, most commonly, filter cartridges containing either depth filter fleeces or membrane filters. Such membrane filters are available in a large variety of membrane polymers for different applications. These materials are discussed later in the chapter. 

The filter measures inhaled mass. In the insert is a sketch of the filter configuration used to measure exhaled particles (and hence deposition) and a gamma camera for regional studies. 

In addition to assessing the probability of release to the SCB, the potential for mitigation of the release by ventilation system filters should be considered. For releases to the SCB s, two charcoal filters and one HEPA filter exist in series in the ventilation system. Each filter Is assumed to be either fully operational (O), degraded (D), or failed (F). Thus, there are 27 potential filter configuration combinations. However, since two identical charcoal filters exist, there are only 18 unique combinations. If the potential for failure of each filter is considered to be an independent event, the likelihood of each combination of filter configurations is calculated as summarized In Table 3E.2-2 ... 

Based on the radiological inventory of isotope targets described in Chapter 3, the consequences at the exclusion boundary for the following filter configurations have been calculated ... 

Fabric Filters. Fabric filters normally use either woven or felt type cloth in the common bag-filter configuration. The fabric is made into bags 6-10 in. in diameter and 6- ft long. The air flow can be in either direction through the bag wall. The dust is periodically removed from the bag either by a shaking mechanism or by a reverse flow pulse-jet. Means are provided in either style so that only a fracrion of the total number of bags are being cleaned at any one time. 

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