Combined filters

SX gas filters and combined filters against specific named compounds used m respiratory... 

The reaction product mixture is a homogenous solution having a pH of about 6. It is evaporated under vacuum to a semisolid residue. To the residue are added 35 ml of water and a few drops of triethylamine to raise the pH to 8. The aqueous solution obtained thereby is extracted successively with 50 ml and 35 ml portions of ethyl acetate, the pH being adjusted to 2 at each extraction with hydrochloric acid. The extracts are combined, filtered, dried over sodium sulfate, stripped of solvent, and evaporated under vacuum. The product is 7-(N-carbobenzoxy-D-o -aminophenylacetamido)cephalosporanic acid in the form of a yellow-white amorphous solid weighing 1.10 g. 

If no practical single filter can be designed to filter all necessary frequencies, then it may be advisable to design two filters that have overlapping characteristics so that a broad attenuation band is yielded by the combination. The attenuation characteristics of two separate filter systems probably will be additive (i.e., if the first section showed a 30% attenuation at 15 cycles per sec and the second section yielded 10% attenuation at 15 cycles per sec, the combined filter arrangement would yield 40% attenuation at 15 cycles per sec). 

The platinum asbestos is removed by filtration and the product which has deposited on this catalyst is dissolved in water. Alcohol is added to the combined filtered solution and washings, and the mixture is cooled with ice to precipitate the product. A second crop of crystals may be obtained by concentrating the solution under vacuum at room temperature, then cooling and adding hydrochloric acid until the pH is below 1. The crystals are thoroughly washed with ethanol. 

The mash from the Streptomyces aureofaciens fermentation broth is acidified and filtered. The filtrate is adjusted to the desired pH, usually 7-8.5, and various flocculating or chelating agents may be added (e.g., vinyl acetate-maleic anhydride copolymer, sodium EDTA, ammonium oxalate, Arquad). The precipitate is (1) stirred with filter aid, filtered, stirred with HC1, refiltered, mixed with 2-ethoxyethanol, filtered, washed, and the filtrates are combined, acidified with HC1, NaCl is added, and the crystals are collected, washed with 2-ethoxyethanol, water, and ethanol, and dried (67), or (2) extracted into methyl isobutyl ketone, the extracts are combined, filtered, and acidified with HC1, and the crystals are collected and washed with water, 2-ethoxyethanol, and isopropanol, and vacuum-dried. If the crystals are greenish, they are treated with sodium hydrosulfite at pH 1.8, filtered, washed, and dried as in (1) above (68). 

In this method the sample (1—20g) is weighed in a flask, internal standard is added, and the sample acidified with hydrochloric acid to pH2-3. When the evolution of gas has ceased, the slurry is extracted with three portions (10, 5 and 5mL) of a 0.25% ethereal Tropolone solution. After being shaken vigorously and centrifuged, the organic phases are combined, filtered through anhydrous calcium chloride, and reduced in volume to about 2mL at room temperature by a rotary evaporator. The extract is then ready for derivatization. 

A combined filter and manure system must be completely reliable, since it is not easy to make repairs under the slats. After 2-3 years of experience a system which works well has been developed. (2, 3, 4) In Fig.2 a schematic diagram of the filter system is shown under the slatted floor. In the channel under the slats two angle sections (1) are attached one above the other and fixed over the whole length to both walls. These are covered from above with protective plates (2) joined underneath the slats. The filter net (3) is provided with... 

Both these reactions are catalysed by the foregoing catalysts. For the efficient preparation of the chloride, the dry reacting gases arc brought together at ordinary temperatures in the presence of a catalyst such as Norit, a highly activated powdered carbon. The mixture is then cooled to —10° C. to ensure complete combination, filtered from the catalyst and carefully distilled, the heat being applied to the liquid for as short a time as possible.2... 

Figure 7.14 The pressure difference across the prefilter, the final filter and the combined filters for various combinations of prefilter and final filter. The optimum prefilter distributes the particle load evenly between the two filters so both filters reach their maximum particle load at the same time. This maximizes the useful life of the combination...

A mixture of 0.25 percent sodium bisulphite and 0.25 percent sodium sulphite (o.d. bark) was added to the combined filtered extracts. The extracts were concentrated under reduced pressure at 35° to 55°C in a circulating vacuum evaporator. The extract... 

A potential problem with the analysis of biological fluids, especially plasma samples from in vivo studies, is the risk of clogging of SPE cartridges and/or analytical columns. Therefore, filtration of such samples prior to LC or SPE is recommended. Combined filtering and protein precipitation in 96-well plate format was described [97-98]. The samples are collected and stored frozen in sealed 96-well polypropylene filter plates. Prior to SPE and LC-MS analysis, the seals are removed and the plate is placed on top of a 96-well SPE manifold As the plasma thaws, it passes through the filter and into the SPE device. 

Combined Filter Effluent Installation. The effluents from filtration units are combined and sent to the UV disinfection unit(s). The disinfected water is then pumped to the water storage. Of the three options described here, this installation is generally preferred when conditions permit. The UV operation is independent of the operation of individual filtration units, leading to great flexibility for design and operation. If the entire UV installation failed, a chemical disinfectant such as chlorine can be directly added to the water storage. 

Fig. 9. Schematic for installation of post-filtration pre-water storage UV disinfection in water treatment (A) combined filter efflnent installation (B) individual filter efQnent piping installation.

A similar but more improved evaporation lagoon system has been used at Feura Bush Filtration Plant of the City of Albany, New York, USA. The City of Albany s evaporation lagoon system involves the use of natural evaporation, freezing, thawing, and sedimentation processes for treatment of combined filter backwash water and sedimentation waste slndge. 

Figure 3-7 Spectral characteristics of a sharp-cutoff filter (a) and a wide-bandpass filter (b). The narrow-bandpass filter (c) is obtained by combining filters a and b. The spectral bandwidth of filter c (distance n-m) is defined as the width in nanometers of the spectral transmittance curve at a point equal to one half of maximum transmittance.

The Parr oxygen combustion bombs were used for a rapid ash determination and for sample preparation for IC. About 0.5 g of shale or shale oil was mixed with 0.5 g of white oil in a stainless steel cup. Five mL of water was placed in the bottom of the bomb which was then assembled and pressurized to 30 atmospheres of oxygen. After combustion, the bomb was allowed to cool for ten minutes and then opened slowly. The inside walls of the bomb were washed with water, and all the washings were combined, filtered if necessary, and diluted to 50 mL. The residue in the cup was dried at 110°C for 15 minutes and reweighed for ash determination. 

Fine filtration with ultrasonic treatment under the conditions of developed cavitation1 allows one to use 3- and 5-layer fiberglass filters with a cell of 0.4 x 0.4 mm in size or combined filters with 10 to 15 layers containing more coarse fiber. 

The echo maxima are weighted by a function of both T and T2. Similarly, the stimulated echo (Fig, 7.2.1(c)) can be used as a combination filter to introduce T and T2 weights. The echo time (tf2 in Fig. 7.2.19(c)) determines the T2 weight and the mixing time between the second and the third pulses (tn in Fig. 7.2.19(c)) the T weight. Note that the filter transfer functions for T) contrast by saturation recovery and the stimulated echo are inverted (cf. Fig. 7.2.1 (a) and (c)), so that both combination filters introduce different contrasts (cf. eqn (7.2.3)). 

Heterogeneous soft matter, in particular polymer materials, are often characterized by distributions of correlation times of molecular motion. For relaxation studies of polymers, sophisticated filters have been developed which fit the classification of combination filters because they combine Tj and Tip relaxation [Gotl, Gbt2, G6t3]. These filters can be used... 

Fig. 7.2.23 [Gotl] Combination filter for selection of magnetization from polymer chains with intermediate mobility.

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