All articles starting with P
28,818 articles
Pyrochlore quantum spin liquid
A pyrochlore quantum spin liquid is a proposed magnetic state where moments on the pyrochlore lattice of corner-sharing tetrahedra stay disordered yet quantum-entangled to the lowest temperatures.
Pyrochlore structure
The pyrochlore structure is a cubic crystal structure of formula A₂B₂O₇, an ordered superstructure of fluorite underlying oxides studied for frustrated magnetism, catalysis, ionic conduction, and nuclear waste immobilization.
Pyroclastic flow
A pyroclastic flow, also called a nuée ardente, is a hot, dense mixture of volcanic ash, rock fragments, and gas that races down a volcano's flanks at over 100 km/h.
Pyrococcus
Pyrococcus, genus of hyperthermophilic marine archaea (Thermococcales) named by Fiala and Stetter in 1986; grows optimally near 100 degrees C, ferments sugars to hydrogen, and includes P. furiosus, source of Pfu polymerase and SHI hydrogenase.
Pyrococcus abyssi
Pyrococcus abyssi (strain GE5) is a hyperthermophilic anaerobic euryarchaeon from North Fiji Basin vents at 2,000 m, growing optimally at 96°C, with two replicative DNA polymerases (PolB, PolD) and the Isis PCR polymerase.
Pyrococcus furiosus
Pyrococcus furiosus, hyperthermophilic anaerobic archaeon from Vulcano Island, Italy, grows optimally near 100°C; source of Pfu polymerase and oxygen-resilient SHI hydrogenase used in biofuel cells.
Pyrocumulonimbus
A pyrocumulonimbus, or pyroCb, is a thunderstorm generated by wildfire heat, officially named flammagenitus, that injects smoke high into the atmosphere and spreads embers and lightning.
Pyrocystis fusiformis
Pyrocystis fusiformis, a large non-motile bioluminescent marine dinoflagellate (Pyrocystaceae, Gonyaulacales), about 370 µm long, photosynthetic and non-toxic, flashing ~500 ms when sheared; widely cultured and used as a UBAT calibration species.
Pyrodictium
Pyrodictium: anaerobic disc-shaped hyperthermophilic archaea (Pyrodictiaceae, Desulfurococcales) from submarine vents, growing optimally at 97–105°C (max 110°C), connected by unique hollow cannulae, reducing sulfur with hydrogen; species include P. occultum and P. delaneyi.
Pyroelectric energy harvesting
Pyroelectric energy harvesting converts time-varying temperature into electricity using pyroelectric materials whose polarization changes with temperature, suiting wearables, sensors, and low-grade waste heat below 100 °C.
Pyroelectricity
Pyroelectricity, or the pyroelectric effect, is the property of certain polar crystals in which a temperature change generates electric charge on opposing faces, chiefly used in uncooled infrared detectors.
Pyrogallol
Pyrogallol, also called pyrogallic acid, is the simplest benzenetriol, a white solid prepared from gallic acid by Carl Wilhelm Scheele in 1786 and long used as a photographic developer and oxygen-absorbing reagent.
Pyroglutamic acid
Pyroglutamic acid, also called pidolic acid or 5-oxoproline, is the cyclic lactam of glutamic acid, an intermediate in glutathione metabolism and a common protein modification.
Pyrokinesis
Pyrokinesis: the alleged ability to ignite or control fire by psychic concentration; a form of psychokinesis popularized by Stephen King's 1980 novel and standard in fiction, but not demonstrated scientifically.
Pyrola
Pyrola (wintergreens) is a genus of about 42 accepted evergreen herbs in Ericaceae, tribe Pyroleae, native to subarctic and temperate Northern Hemisphere to Guatemala and Sumatera; Asian origin, dust-seed mycoheterotrophy, and use as the Chinese medicine Luxiancao distinguish it.
Pyrolusite
Pyrolusite is a manganese oxide mineral with formula MnO₂, the most stable polymorph of manganese dioxide and the principal ore of manganese, used to decolorize glass since antiquity.
Pyrolysis
Pyrolysis, also called pyrolytic decomposition, is the thermal decomposition of organic materials in the absence of oxygen, typically at 300 to 800°C, yielding char, bio-oil, and gas.
Pyrolysis gas chromatography
Pyrolysis gas chromatography (Py-GC) is an analytical technique in which a sample is thermally decomposed in an inert atmosphere and its fragments are separated by gas chromatography.
Pyrolysis of plastics
Pyrolysis of plastics is a chemical recycling process that heats plastic waste without oxygen, breaking it down into oil, gases, and char usable as fuels or feedstocks.
Pyrolysis oil
Pyrolysis oil, also called bio-oil or py-oil, is the dark brown liquid made by heating biomass or waste without oxygen, used as burner fuel or upgraded into transportation fuels.
Pyrolysis–gas chromatography–mass spectrometry
Pyrolysis–gas chromatography–mass spectrometry (Py-GC-MS) is an analytical technique that thermally decomposes a sample in an inert atmosphere, separating and identifying the volatile fragments by GC-MS.
Pyrolytic carbon
Pyrolytic carbon is a carbon material deposited from gaseous hydrocarbons on substrates at 1000 to 2500 K, used in nuclear fuel particles and mechanical heart valves.
Pyrolytic graphite
Pyrolytic graphite is a highly oriented form of graphite made by chemical vapor deposition, with thermal and electrical properties that differ sharply along and across its layers.
Pyromania
Pyromania is a rare impulse control disorder marked by repeated deliberate fire setting for tension relief, not profit or revenge. Also called pathological fire setting; DSM-5 and ICD-11 diagnose it, treatment evidence remains limited.
Pyromania (album)
Pyromania is Def Leppard's third studio album, released January 20, 1983, produced by Mutt Lange. It reached No. 2 on the Billboard 200, sold over 10 million US copies, and launched the hits Photograph, Rock of Ages, and Foolin'.
Pyromellitic acid
Pyromellitic acid, or benzene-1,2,4,5-tetracarboxylic acid, is a tetracarboxylic acid with four carboxyl groups on a benzene ring, used in powder coatings and as a metal–organic framework linker.
Pyromellitic dianhydride
Pyromellitic dianhydride (PMDA) is the dianhydride of pyromellitic acid, a white hygroscopic crystalline solid made from durene and best known as the comonomer with 4,4′-oxydianiline in DuPont's Kapton polyimide film.
Pyrometallurgical recycling
Pyrometallurgical recycling is a battery recycling method that smelts spent lithium-ion batteries above 1200 °C to an alloy, recovering over 95% of cobalt, nickel, and copper.
Pyrometer
A pyrometer, also called an optical pyrometer or radiation thermometer, is a non-contact instrument that measures temperature by detecting thermal radiation, letting it measure moving or very hot objects.
Pyrometry
Pyrometry is the measurement of a surface's temperature from its emitted thermal radiation without contact; pyrometers infer temperature from radiance using Planck's or the Stefan–Boltzmann law.