Terms starting with P

Control chart for the fraction of nonconforming units in each sample, built on the binomial distribution.

Precision-to-tolerance ratio: measurement system spread as a fraction of the specification width.

Probability of seeing a result at least this extreme if there were truly no effect, used to judge statistical significance.

To fill a bearing by hand, forcing grease between the rolling elements before assembly. Shop talk

Replacing the spin pack, including its filters and spinneret, on a spunbond beam or fiber spinning position. Shop talk

Compressible rings packed around a valve stem to stop process fluid leaking out to atmosphere.

Lab talk for a stack of sheets thick enough to be opaque, used for R-infinity, brightness and color readings. Shop talk

Exposed copper area on a board where a component lead or terminal is soldered.

Polyalkylene glycol, a synthetic base oil prized for low friction and clean running but hostile to most other oils.

Acrylic latex caulk used to fill interior trim gaps for painting, with little movement capability. Shop talk

A round steel float disc clipped onto a power trowel's blades for the first, flattening machine passes. Shop talk

Shop word for a narrow slit roll wound straight on itself, far wider in diameter than it is tall. Shop talk

Very shallow round box, about half an inch deep, used to mount a fixture where no deeper box will fit. Shop talk

A flat, wide-window Geiger-Mueller detector used for frisking because it picks up beta and alpha contamination well. Shop talk

One continuous piece of geomembrane as deployed, numbered and tracked through seaming and testing.

Arranging several boards on one production panel so they are fabricated and assembled together.

Polyalphaolefin, the synthetic hydrocarbon base oil built from alpha-olefins and classed as Group IV.

A simple cylindrical stage light holding a sealed-beam PAR lamp, the classic rock-and-roll and touring fixture. Shop talk

Matched pairs of ground steel bars used to raise a part in the vise to a known, level height.

Tiny discharge in a void, on a surface or at a sharp edge that never spans the whole insulation, an early sign of decay.

The share of the total pressure contributed by one gas species in a mixture.

Moving an emergency shutdown valve a small part of its travel while online, to prove it is not stuck.

Count of solid particles per volume of oil, sorted by size, used to track dirt and wear debris.

Sensors that measure the temperature, speed and size of particles in flight to monitor the spray process.

Cutting a finished part off the end of the bar on a lathe with a thin blade-shaped tool.

The SI unit of pressure, one newton per square metre, used in standards and on calibration certificates.

One run of combustion gases from end to end through a boiler before they turn or leave.

One sweep of the gun across the area being coated; the coating is built up pass by pass.

Leaking through the seat while closed, so fluid still gets past a valve that is supposed to be shut. Shop talk

An acid treatment that strips free iron from stainless fasteners and restores their chromium oxide film.

To connect two ports, usually equipment to panel or panel to panel, with a jumper. Shop talk

Piece of geomembrane extrusion-welded over a hole, defect, destructive sample cut-out or failed seam section.

A rack-mounted enclosure of adapters where permanent cable fibers end and jumpers connect them to equipment.

A set of calibration lines over flat ground and slopes that measures sonar alignment biases and timing error.

Pressure aging vessel: the test that ages binder under heat and pressure to simulate years of service on the road.

The self-propelled machine that receives hot mix, spreads it to width and lays it as a smooth, partly compacted mat.

A multiplier applied to the contract price for a lot of asphalt based on its test results.

Post color number: a Kubelka-Munk measure of how much a pulp yellows during an aging test.

Precipitated calcium carbonate: a synthetic filler, often made beside the mill, that raises brightness and opacity.

Personnel contamination event: contamination found on a worker's skin or personal clothing above a set threshold. Shop talk

Pyrometric cone equivalent: a refractory's softening point expressed as the number of a matching standard cone.

Personnel contamination monitor: a walk-in booth that scans the whole body for contamination at exits.

Probability density function, the curve describing how likely each possible value of a quantity is.

Concrete made with 3/8 in pea gravel instead of standard coarse stone, so it moves through small pump hoses. Shop talk

The highest instantaneous power reached during a laser pulse, roughly pulse energy divided by pulse duration.

To fine-tune alignment knobs while watching a power meter or signal until the reading reaches its maximum. Shop talk

A layered mix of ferrite and cementite that forms when austenite cools slowly through the eutectoid range.

To drill a hole in short steps, backing out between them to clear chips and let coolant in.

A low, broad background of light under or around an ultrashort pulse, which carries energy outside the main peak.

The force needed to strip a flexible bonded layer off a surface, given per unit width.

Describing any product with a ready-coated pressure-sensitive adhesive under a liner that goes on without tools. Shop talk

Field name for self-adhered membrane: rubberized asphalt or butyl sheet with a release liner on the back. Shop talk

A fabric layer cured onto a composite surface and torn off just before bonding to expose a clean, textured face.

Tension pulling one adherend away from the other at the edge of a bond, concentrated along a thin line.

Seam test that pulls the top sheet away from the bottom sheet across the weld to check how well they fused.

Said of a gauge stuck at the top or bottom end of its scale, giving no usable reading. Shop talk

Single conductor that serves as both the neutral and the protective earth in a TN-C network.

A pocket ion chamber dosimeter shaped like a pen, read by looking through it at a light. Shop talk

A scratch test that rates film hardness by the hardest pencil lead that will not gouge it.

Shop slang for filling in calibration or inspection records without actually doing the measurements. Shop talk

How deep the weld fuses into the base metal or the joint beyond the original surface.

A binder rating based on how far a weighted needle sinks into the asphalt at 25 C.

Shorthand that states voltages, currents and impedances relative to chosen base values, so 1.0 means nominal.

How deep an internal thread is compared with full theoretical depth, set mainly by the tap drill size.

Hitting a machine or part to make it work, dressed up in technical language. Shop talk

An especially large spring tide that occurs when new or full moon falls close to the Moon's nearest approach to Earth.

A pair of stacked mirrors that changes a laser beam's height above the table, and optionally rotates its polarization.

Gas passing through the solid walls or seals of a vacuum system by dissolving into and diffusing through them.

Formal written authority to work on equipment that has been isolated, earthed and declared safe.

Rate of water flow across a geotextile per unit head, the basic measure of its cross-plane flow capacity.

Joking name for a hammer or big pry bar, the tool used when something needs convincing to fit. Shop talk

Shop name for a hammer, usually a big one, used to convince a stuck part to move. Shop talk

Probability of false accept, the chance that a nonconforming item is measured and passed as good.

Probability of false reject, the chance that an item actually in tolerance is measured and failed.

Performance Grade: the binder rating that names the hottest and coldest pavement temperatures a binder can handle.

How far a constituent's local high water trails the corresponding astronomical forcing, given in degrees.

Keeping interacting waves in a nonlinear crystal in step so the generated light builds up instead of canceling.

A cross-shaped recess drive with tapered walls, the default drive on sheet metal, wood and small machine screws.

A slow, permanent rise in background loss in rare-earth-doped fiber under pumping, which erodes output power.

Describes daylight vision, when cones dominate, providing color and sharp detail at luminances above a few cd/m squared.

Automated machine that picks surface mount parts from reels and trays and sets them on a pasted board.

To receive radiation dose while doing work, as in picking up 20 millirem on a job. Shop talk

An optic, usually an uncoated wedge, that samples a small fraction of a beam and sends it to a diagnostic. Shop talk

Mix sticking to roller tires or drums and tearing out of the mat, leaving pockmarks behind. Shop talk

Threshold at which a protection element starts to operate, and the moment the measured value crosses it.

Metal transferred from one sliding surface onto another, seen as smeared lumps after adhesive wear. Shop talk

A visible border of heavier or darker coating around the edges of a flat panel. Shop talk

A heavy lead or tungsten container used to store or carry a radioactive source or sample. Shop talk

An intermodal train hauling highway trailers on flatcars. Shop talk

A looped siphon pipe between a steam boiler and its pressure gauge or control, filled with condensate to block live steam. Shop talk

Short length of wire spliced to several conductors so only one lead goes to a device terminal. Shop talk

A short fiber with a factory connector on one end and bare fiber on the other, spliced onto a cable to terminate it.

A short jumper wire spliced into a group of conductors so they can share a single terminal. Shop talk

A small flame that lights the main burner and is often used to prove ignition before main fuel flows.

To close a valve partway to cut flow or pressure, without shutting it. Shop talk

A valve that shuts off flow by squeezing a flexible rubber sleeve closed, either mechanically or with air pressure.

One transmit-and-listen cycle of a sonar; as a verb, to run the sonar.

Tiny hole in a barrier fabric or film that lets liquid or particles through.

A tiny hole running through the cured film, often down to bare metal.

The smaller of two meshing gears, usually the driver in a speed reducer.

How far the hypoid or bevel pinion sits along its axis toward the gear, set with shims behind its bearing.

Shop word for conduit of any kind, and as a verb for installing it, as in pipe it. Shop talk

Paste thread sealant brushed on male pipe threads before makeup to seal and lubricate the joint. Shop talk

Voltage between a buried pipe and a reference electrode on the soil surface, the basic CP measurement.

Soil particles washing through a filter or out of an embankment, leaving voids and channels behind.

Thermal conductivity gauge that reads pressure from how quickly gas carries heat away from a hot wire.

The distance from one thread crest to the next, measured parallel to the screw axis.

Bow-up or bow-down rotation of a vessel, which shifts sonar footprints forward or aft along the track.

Errors in tooth spacing, either from one tooth to the next or accumulated around the gear.

The diameter at which thread thickness equals the gap between threads, the dimension that controls fit.

The diameter of the pitch circle, the imaginary rolling circle on which tooth size and gear ratio are based.

Localized corrosion that drills small, deep cavities into metal while the surface around them stays nearly intact.

Surface fatigue of gear teeth that breaks out small craters, typically on the flank just below the pitch line.

Rolling contact fatigue that leaves visible craters on gear teeth or bearing races.

The line of whites on a chromaticity diagram that a perfect blackbody passes through as it heats up.

A compact gear arrangement of a central sun, orbiting planets on a carrier and an outer ring gear.

Cutting with an arc squeezed through a small nozzle into a hot, fast gas jet that melts and blows out a narrow kerf.

The gas mix ionized in a plasma gun: a primary gas for flow plus a secondary gas for heat.

Spraying powder through an electric arc plasma jet hot enough to melt ceramics and refractory metals.

Exposing a surface to ionized gas to clean it and add reactive groups that raise its surface energy.

Moist, workable refractory delivered ready to use and pounded into place with a pneumatic rammer.

Cracks that open in fresh concrete before it sets, when the surface dries faster than bleed water replaces it.

Softening agents moving out of flexible plastics into an adhesive layer and weakening it over time.

Electrochemical deposition of copper or other metals on a board, building hole walls and surface conductors.

A waterproofed structural slab over occupied space, topped with pavers, soil, planters or a wearing slab.

Permanent linear change: the lasting shrinkage or growth of a refractory after heating and cooling.

A box on the supply or return side of an air handler that feeds or collects several ducts, or a ceiling cavity used as a return path.

A blockage that jams a concrete pump line or hose, stopping placement until it is cleared. Shop talk

A short piece of rail cut into the track to replace a section with a defect or a break. Shop talk

A quarter-turn valve that rotates a tapered or cylindrical plug with a port through it to start or stop flow.

Silicone stoppers pushed into holes and threads so powder stays out, often reused many times. Shop talk

The cloud of radioactive gases and particles carried downwind from a release.

The visible jet of hot gas and glowing particles streaming from the spray gun toward the part.

Polarization-maintaining fiber: fiber with built-in stress that keeps linearly polarized light in its launch orientation.

Part metal temperature, the temperature of the substrate itself, which is what actually drives the cure.

Pressure nominal: the metric rating series, such as PN 16 or PN 40, used for European and ISO valves and flanges.

A rubber-tired roller whose offset tires knead the mat, closing surface voids during intermediate rolling.

An electro-optic crystal that changes a beam's polarization when high voltage is applied, used as a fast optical switch.

Telescoping prop used to hold bricks against the upper shell of a rotary kiln until the ring is keyed. Shop talk

Calender bonding with an engraved roll that fuses the web only at small, regularly spaced points.

A lighting calculation that predicts illuminance at each point on a grid from every luminaire's photometric data.

The place in a closed hydronic loop, where the expansion tank connects, whose pressure the pump cannot change.

Shop shorthand for Rockwell numbers, as in a part running two points high on hardness. Shop talk

Mill shorthand for units of brightness, opacity or whiteness on their percentage or index scales. Shop talk

The titration reading for a washer bath, given in milliliters of titrant and used to judge bath strength. Shop talk

Any material that absorbs neutrons strongly, whether added deliberately for control or produced by fission.

The arrangement that ensures each transmitter in a fiber link connects to the receiver at the far end.

Shift of a metal's potential away from its native value caused by current flowing across its surface.

A sonar transducer fixed on a rigid pole over the side or bow of a boat instead of built into the hull. Shop talk

Grade from 1 to 4 describing how much conductive dirt and moisture can settle on insulation in a location.

Powder based on polyester resin, the standard choice for outdoor parts because it holds color and gloss in sunlight.

Binder blended with an elastic polymer, usually SBS, to resist rutting in heat and cracking in cold.

A water solution of polymer that quenches at a speed between water and oil, tuned by its concentration.

An elastomeric sealant, usually two-part, chosen for joints exposed to fuel, chemicals or constant immersion.

Non-soap grease thickener with long high-temperature life, standard in sealed electric motor bearings.

An adhesive based on isocyanate chemistry that cures into a tough, somewhat flexible bond.

A tough, paintable elastomeric sealant used widely on concrete, masonry and traffic joints.

Passive Optical Network: a point-to-multipoint fiber network where unpowered splitters share one fiber among many users.

A group of road crews who rotate between two terminals in first-in, first-out order. Shop talk

For a safety valve to lift suddenly and fully open, discharging with a loud blast at set pressure. Shop talk

A part that lets go with a snap, leaving the adhesive cleanly on one side and nothing on the other. Shop talk

Shop slang for the safety valve on a steam boiler or the relief valve on a hot water boiler. Shop talk

An LED dimming fault where fixtures stay off at low dimmer settings and then suddenly turn on at a higher level. Shop talk

Shop name for a blind rivet: a hollow rivet set from one side by pulling a mandrel that snaps off when tight. Shop talk

Cracking of a plastic IC package in reflow when absorbed moisture flashes to steam, sometimes with an audible pop. Shop talk

A small conical crater where a swelling stone just under the surface pushed out a chip of concrete.

The condition where more atoms occupy the upper laser level than the lower one, which a medium needs to give gain.

The fraction of a coating's volume made of voids between and within splats, usually reported in percent.

Gas bubbles trapped in weld metal as it freezes, showing as round holes on the surface or on film.

Removable earthing leads clamped onto isolated conductors to short them together and to earth during work. Shop talk

The gray powder that reacts with water to bind sand and stone together into concrete.

A device on a control valve that compares the control signal with actual valve position and adjusts air to match.

The face of a wall or slab that touches the water source, where waterproofing works best.

Extra time at elevated temperature after the first cure, which finishes crosslinking and raises Tg and heat resistance.

Shop name for the pressure blast vessel that holds grit and feeds it into the blast hose. Shop talk

How long a mixed batch of two-part adhesive stays usable before it thickens too much to apply.

Working time after mixing a two-part coating before it has reacted too far to apply properly.

Shop name for cheap, low-melting die-cast alloy, usually zinc-based, that is brittle and almost impossible to weld. Shop talk

Shop name for a thin, flat part that warps into a dished or wavy shape during the quench. Shop talk

Field name for the termination where an underground power cable meets an overhead line or equipment. Shop talk

A bowl-shaped hole through the pavement surface where pieces of asphalt have broken out.

The act of placing concrete, or one placement itself, in everyday jobsite speech. Shop talk

Coldest temperature at which a chilled oil still moves in its test jar, a lab benchmark for cold flow.

The hopper and metering unit that delivers a steady, measured flow of powder to the spray gun.

The locomotives assigned to a train, or locomotives in general. Shop talk

Probability that a test will detect a real effect of a given size, set by sample size, noise and alpha.

A burner with its own fan that forces combustion air into the furnace, rather than relying on natural draft.

Ratio of active power to apparent power, showing how much of the current drawn does useful work.

Cutting gear teeth with a gear-like cutter spinning at a crossed axis angle in continuous high-speed rotation.

A gas or electric machine with rotating blades that floats and trowels large concrete slabs.

Polypropylene: the most widely used polymer in nonwovens, especially spunbond and meltblown fabrics.

Post-processed kinematic: GNSS positions computed after the survey from logged rover and base data, at centimetre level.

Process performance index: a Cpk-style figure computed with the overall standard deviation, capturing long-term variation.

Magnetic measure of total ferrous debris in an oil sample, including large particles that spectrometers miss.

Procedure qualification record: the documented test weld and results that support a WPS.

A working light fixture that appears in the scene itself, such as a table lamp, sconce or neon sign. Shop talk

Heating a casting or galvanized part before coating to drive out trapped gas that would blow holes in the film.

Short for pre-terminated cable: factory-made assemblies with connectors already on, pulled in and plugged in. Shop talk

Strengthening an alloy by forming very fine particles inside its grains through solution treating and aging.

How well repeat readings of the same item agree with one another, with no reference to whether they are right.

Impregnated open-cell foam supplied squeezed flat that slowly expands to fill and seal a joint.

Warming the substrate before spraying to drive off moisture and reduce stress at the coating interface.

Heating base metal before welding to slow cooling and drive off moisture, preventing hydrogen cracks.

The tension created in a bolt by tightening it, which clamps the joint and keeps it from slipping or opening.

Pitting resistance equivalent number: an index of a stainless alloy's chloride pitting resistance from its chemistry.

Glass cloth soaked in partly cured resin, used as the bonding layer that glues cores together in a multilayer board.

The angle between the line of tooth contact force and the tangent to the pitch circle, usually 20 degrees.

The standardized rating step, such as 150, 300 or 600, that sets a valve or flange's allowable pressure at each temperature.

A submerged sensor that measures the weight of water above it, converted to water level with density and air pressure.

A closed gate valve that cannot be opened because trapped pressure in its bonnet cavity jams the wedge into both seats.

Shop name for the pressure switch that starts and stops a steam boiler's burner to hold pressure in a set range. Shop talk

The cleaning and chemical conditioning a part gets before powder, which decides most of its adhesion and corrosion life.

A nut built to resist turning on the thread before it seats, using a nylon insert or deliberately distorted threads.

Describes hydronic piping where each circuit has its own pump and connects to a main loop through two closely spaced tees.

A standard that gets its value straight from the unit definition, not from calibration against another standard.

A low-viscosity asphalt sprayed onto granular base to soak in, seal it and bind loose surface particles before paving.

A thin first coat wiped or sprayed onto a bonding surface so the adhesive grips better or the fresh prep stays clean.

A thin liquid brushed or wiped onto a joint face or deck so the sealant or membrane bonds reliably.

Sudden surges that throw slugs of boiler water out with the steam.

Gloss of the printed ink film on a paper, as distinct from the gloss of the bare sheet.

Opacity calculated as single-sheet reflectance over black divided by the reflectance of an opaque pad of the same paper.

How well a stable process's natural spread fits inside the specification limits, usually expressed as an index.

Judging a lab's performance by having it measure circulated items and scoring its results against a reference value.

How far a tooth's actual shape from root to tip departs from the intended involute and modifications.

Moving the cutter in or out from the standard position, making teeth fatter or thinner without changing pitch.

The tensile load a full-size fastener must hold without measurable permanent stretch, about 90 percent of yield.

The metric strength grade of a bolt or nut, stamped on the head as a number such as 8.8, 10.9 or 12.9.

A rigid sheet laid over a finished membrane so backfill, rebar and foot traffic cannot puncture it.

Device that watches currents and voltages and orders a circuit breaker to trip when it detects a fault.

To test isolated equipment with a verified voltage detector and confirm no voltage before anyone touches it. Shop talk

To run a new CNC program cautiously the first time, watching every move to catch errors before they crash. Shop talk

Pressure-sensitive adhesive, the always-tacky layer on tapes and labels that bonds under finger pressure with no cure step.

Probabilistic safety assessment: a systematic model of how accidents could happen and how likely each outcome is.

The science of air and the water vapor mixed into it, used to design and diagnose heating, cooling and humidity control.

Post-tensioning: reinforcing concrete with steel tendons that are stretched tight after the concrete hardens.

Penetrant testing: revealing surface-breaking cracks by drawing colored or fluorescent dye out of them.

Pressure-temperature chart: a table giving each refrigerant's saturation temperature at each pressure.

Positive train control: an onboard and wayside system that stops a train before it breaks a speed limit or authority.

Plated through-hole: a drilled hole whose walls are copper-plated to connect every layer it passes through.

Lab slang for a compacted cylindrical mix specimen, especially one made in the gyratory compactor. Shop talk

Shop word for the weld pool, the molten metal under the arc that the welder watches and steers. Shop talk

A small explosion of oil vapor in the combustion chamber that blows soot and smoke out of the burner and into the room. Shop talk

One continuous paving pass from the start to the end of a run, or the lane width paved in that pass. Shop talk

A cable pulling operation, from setup at the feed end to the cable arriving at the far vault. Shop talk

To take a load or part out of the furnace, usually on its way to the quench or at the end of a cycle. Shop talk

To evacuate a refrigeration system with a vacuum pump, removing air and moisture before charging. Shop talk

A break in the rail, usually at a joint or weld, caused by the rail shrinking in extreme cold. Shop talk

Test that glues a dolly to a coating and pulls it off to measure how strongly the coating sticks.

To uncouple cars by lifting the coupler's pin with the cut lever; also, to retire from the railroad. Shop talk

Particles torn out of a coating during polishing, leaving holes that look like porosity in the mount.

How long a laser pulse lasts, normally given as the full width at half maximum of its intensity.

Uneven powder delivery that makes the spray stream surge and flicker instead of flowing steadily. Shop talk

The energy source that excites a gain medium, or the act of supplying it, usually with diodes, flashlamps or current.

A fused fiber component that merges the outputs of many pump diodes into the inner cladding of a double-clad fiber.

Moving a system's refrigerant into the condenser or receiver by shutting the liquid line and running the compressor.

To evacuate a chamber from atmosphere to its working pressure, through roughing, crossover and high vacuum. Shop talk

Plot of chamber pressure against time during a pump-down, used as the fingerprint of a healthy system.

Fines from a wet subgrade being forced up into the aggregate base by repeated traffic loads.

Placing a hydronic circulator just downstream of the expansion tank so it pushes water away from it. Shop talk

Volume of gas a pump removes from its inlet per unit time, measured at the inlet pressure.

Shop name for the round differential housing in the middle of a drive axle, from its bulging shape. Shop talk

Number of needle penetrations per square centimeter of fabric, the basic dose of needling.

To clean soot from firetube boiler tubes by running a brush on a long rod through each one. Shop talk

Polyurethane reactive hot melt, applied molten like a hot melt, then moisture-cured into a heat-resistant bond.

To run adhesive through a mixer or dispense valve and discard it, clearing old, unmixed or off-ratio material. Shop talk

Blowing air through the furnace and flue before ignition or after shutdown to clear out unburned fuel.

To pump fresh grease into a bearing until the old grease is pushed out of the relief port or seal. Shop talk

Inert gas flowed inside a pipe or behind a joint to keep the back of the weld from oxidizing.

Polyvinyl acetate emulsion, the white or yellow wood glue that sets as its water soaks into the wood.

Polyvinyl chloride: a flexible, plasticized geomembrane that folds and seams easily, used in ponds, canals and water features.

Postweld heat treatment: heating a finished weld to relieve stress and temper the heat-affected zone.

Percent within limits: a statistical measure of how much of a lot falls inside the specification limits.

The practice of measuring and controlling furnace temperature: sensors, instruments, calibration and surveys.