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Porous materials which primarily retain contaminants on the influent face, performing the actual process of filtration.
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Related Terms |
DEAD TIME
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AMPLIFICATION
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POLYFORMING
A noncatalytic, petroleum-refinery process charging C3 and C4 gases with naphtha or gas oil at high temperature to produce high-quality gasoline and fuel oil; mostly replaced by catalytic reforming; the prodTesting and Materials analysis of paraffins (P), olefins (O), naphthenes (N), and aromatics (A) in gasolines.
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PNEUMATIC TEST
Pressure testing of a process vessel by the use of air pressure.
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PLUGGING
1. Braking an electric motor by reversing its connections, so it tends to turn in the opposite direction; the circuit is opened automatically when the motor stops, so the motor does not actually reverse. 2. The formation of a barrier (plug) of solid material in a process flow system, such as a pipe or reactor.
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PINCH-TUBE PROCESS
A plastics blowmolding process in which the extruder drops a tube between mold halves, and the tube is pinched off when the mold closes.
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PHOTOELECTRIC LIQUID-LEVEL INDICATOR
A level indicator in which rising liquid interrupts the light beam of a photoelectric control system; used in a tank or process vessel.
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PHOTOFABRICATION
In manufacturing circuit boards and integrated circuits, a process in which the etching pattern is placed over the circuit board or semiconductor material, the board or chip is placed in a special solution, and the assembly is exposed to light.
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PHOSPHORIC ACID POLYMERIZATION
A petroleum-refinery process using phosphoric acid catalyst to convert propylene, butylene, or both, into high-octane gasoline or petrochemical polymers.
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PHENOL PROCESS
A single-solvent petroleum-refining process in which phenol is the selective solvent.
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