Filter specifications

Cellulose membranes can generally tolerate a pH of 3 to 6 and 0.3 to 1.0 ppm of chlorine while TFC membranes can generally tolerate a pH of 3 to 11 and < 0.05 ppm of chlorine. Membrane tolerance is also described as the permittee cumulative ppm-hours of membrane exposure to chlorine. TFC membranes can range from 1000 to 12,000 ppm h. Always check specific filter specifications. RO membranes... 

Filter specifications are matched to the response times of the process. For example, a given process has a time constant of 5 minutes. That means that it can respond over the frequency range of 0 to 1/20 of a cycle per minute. Higher frequencies are attenuated naturally by the process. Thus, if the data contain components beyond 0.05 cycles per minute, then those components are likely to be unwanted interferences. The linear filter would pass the frequencies between 0 and 1/20 and reject frequencies outside this range. The filter should attenuate frequencies higher than one decade above the break-point frequency. Process measurements processed by this filter are transformed to a new sequence with less interference than the original data. In this way, an input mapping has been defined. 

FIR and IIR filters both are able to meet a given filter specification and, in that sense, they are identical. However, FIR filters can be designed for... 

To support the institutional pharmacist in preparing IV admixtures (which typically involves adding one or more drugs to large-volume parenteral fluids), equipment manufacturers have designed laminar flow units, electromechanical compounding units, transfer devices, and filters specifically adaptable to a variety of hospital programs. 

Remove compounds that do not pass a rejection filter (specific for each particular task). 

Binding Characteristics. For ligand-receptor binding assays, we used an EDTA/Tris-citrate (1 mM, pH 7.4)-dialyzed mitochondrial fraction of housefly heads, the so-called 2 fraction, which was prepared by a modification of Squires s method (4). The final pellet was frozen at -25°C and then suspended in 50 mM Tris-citrate buffer (pH 7.4 at 3°C) for assays. 4-w-Propyl[2,3-3h]-2,6,7-trioxa-l-phosphabicyclo[2.2.2]— octane 1-oxide ([ HjPr-BP, 41 Ci/mmol) was used as a ligand for the reason described above. Radioreceptor assays were performed by filtration techniques with glass fiber filters. Specific [ HjPr-BP binding was taken as that displaced by excess unlabeled Pr-BP(10 yM). 

As well as the filter-specific maximum concentrations based on the adsorptive capacity, the rates of leakage of the used masks must also be considered. The following restrictions in regard to the occupational exposure levels are to be observed ... 

In some facilities, special electrically shielded rooms minimize environmental electrical noise, particularly 60 Hz alternating current (AC) hne noise. Since much of the information of interest in the EEG lies in frequency bands below 40 Hz, low-pass filters in the amplifier can be used to greatly reduce 60 Hz noise. For attenuating AC noise when the low-pass cutoff is above 60 Hz, many EEG amplifiers employ a notch filter specific only for frequencies in a narrow band centered around 60 Hz. 

Linear-phase FIR filters can be designed to meet various filter specifications, such as low-pass, high-pass, band-pass and bandstop filtering. For a low-pass filter, two frequencies are required, namely, the maximum frequency of the pass band below which the magnitude response of the filter is approximately unity, denoted the pass-band corner frequency fp, and the minimum frequency of the stop band above... 

The analog low-pass filter specification, as shown in Fig. 8.106, is given by... 

FIGURE 8.10. Layout of an optical filter [59]. 1, Coherent light source 2, 2, 2", lenses 3, object or transparency 4, spatial filter, specifically, liquid crystal filter 5, control device for the filter and 6, filtered image of the object. 

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