Soft Filters

Whereas hard filters can be considered to be knowledge-driven, soft filters are the result of a data-driven approach. A quantitative structure-activity or structure-property relationship (QSAR/QSPR) is established to predict a property from a set of molecular descriptors. Examples are the above-mentioned in-silico prediction tools for frequent hitters [27] and drug-likeness [41,42] additional models for ADM E properties are described below. 

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The development of predictive models for drug-likeness, frequent hitters, ADME processes, and toxicological endpoints has so far yielded a great deal of soft filters (see discussion above and the compilation of ADMET computational models by Yu and Adedoyin [66]), and the trend still continues to improve both accuracy and... 

Finally, soft filters represented by a GA trained to identify unsuitable compounds that the other filters would fail to find. This algorithm scores compounds for drug-likeness, relative to a training set classified by medicinal chemists. 

The four open test tubes are filled to about 1/5 of their height with yellow iron oxalate, l eC204 1.5 1LO and each tube is heated until the latter has been converted to a black residue. Any water vapor which condenses at the top.s of the I ubes is carefully removed with a soft filter paper. The test tubes are then tightly closed with the rubber bungs and put aside for the demonstration. After show-... 

The degree to which FGD scrubber material is treated influences its physical properties. Basic physical properties include solids content, moisture content, specific gravity, and wet and dry density [67]. When dewatered, the calcium sulfite FGD sludges become a soft filter cake with a solids content typically in the 40-65% range. Calcium sulfate FGD sludges can be dewatered much more easily and may achieve solid contents as high as 70-75% after dewatering [67]. 

The finely ground lichen (0.1-1 g) is boiled three times with a few ml of acetone in a test tube (6 X 160 mm) for some minutes, the hot solution Altered through a soft filter and the combined extracts are concentrated to a volume of 2-3 ml. 

The presence of crimp in the tow is necessary to ensure that the tow can be packaged, processed, and handled easily and to impart bulk to the finished filter. To achieve the latter in the production of the filters, it is necessary to open the tow band (Fig. 12b) to the desired bulk so that the fibers completely fill the paper wrap without voids and soft spots. 

Aluminum compounds, particularly the hydroxides and oxides are very versatile. Properties range from a hardness iadicative of sapphire and comndum to a softness similar to that of talc [14807-96-6] and from iuertness to marked reactivity. Aluminas that flow and filter like sand may be used for chromatography (qv) others are viscous, thick, unfilterable, and even thixotropic (1). 

Soft Materials (1) Talc, dried filter-press cakes, soapstone, waxes, aggregated salt ciystals (2) gypsum, rock salt, ciystahine salts in gener, soft coal (3) calcite, marble, soft limestone, barites, chalk, brimstone. 

Roentgen17 himself established that the rays easiest to absorb ( soft rays k large) came from soft tubes (poor vacuum), and that hard tubes (good vacuum) gave hard rays (k smaller). In this qualitative language, soft rays are filtered out of a polychromatic beam that passes through an absorber and the beam necessarily becomes harder in the process. We know today that, the harder the ray, the shorter its wavelength. 

Eye ointments are prepared in a semi-sohd base (e.g. Simple Eye Ointment BP, which consists of yellow soft paraffin, eight parts hqnid paraffin, one part wool fat, one part). The base is filtered when molten to remove particles and sterilized at 160°C for 2 hours. The drug is incorporated prior to sterilization if heat stable, or added aseptically to the sterile base. Finally, the prodnct is aseptically packed in clear sterile alumirtinm or plastic tnbes. Since the prodnct contains virtnally no water, the danger of bacteria proliferating in the ointment is neghgible. Therefore, there is no recommended maximum period during which they can be nsed. 

A filter press is used to determine the wall-building characteristics of a mud. This press consists of a cylindrical chamber, which may withstand alkaline milieu. A filter paper is placed on the bottom of the chamber. The mud is placed into the chamber and a pressure of 0.7 MPa is applied. After 30 minutes the volume of filtrate is reported. The filter-cake is inspected visually and the consistency is noted as hard, soft, tough, rubbery, or firm. 

This is the process in which soft lead (99.97% pure) is converted into lead oxide. To achieve this, solid bars of soft lead are melted at 400-425°C and the molten lead is oxidized to form lead oxide. The lead oxide so formed, along with some percentage (about 26%) of free lead, is then passed into a cyclone separator and a bag filter. This step is important as it allows the particles of lead oxide to be separated from the air stream in these equipments. The separated lead oxide is then transferred using screw conveyors into storage tanks, called silos. However, air emissions from the bag filter contain lead particles, a source of pollution. 

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