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Fat interesterification
Fat interesterification, which yields interesterified oils, rearranges fatty acids on triglycerides without changing their composition, enabling trans-free margarine, shortenings, and cocoa butter alternatives; chemical and enzymatic routes exist.
Fat-tailed distribution
A fat-tailed distribution, known as a fat tail, is a probability distribution whose tails approach zero slowly, so extreme events occur far more often than Gaussian theory predicts; the Cauchy distribution is the classical example.
Fata Morgana (mirage)
A Fata Morgana is a complex superior mirage, named for Morgan le Fay, in which light bent through layered air distorts distant objects into stacked, changing forms resembling castles.
Fathom
A fathom is a unit of length equal to six feet (1.8288 meters), used chiefly to measure the depth of water, from the Old English word for outstretched arms.
Fatigue (material)
Metal fatigue is progressive structural damage in a material from repeated loading and unloading, typically at stresses below its ultimate strength, causing failure over many cycles.
Fatigue analysis
Fatigue analysis is the engineering assessment of how a component fails under repeated loading at stresses well below its static strength, and how many cycles it survives.
Fatigue limit
The fatigue limit, also called the endurance limit, is the maximum cyclic stress amplitude below which a material can endure an infinite number of cycles.
Fatima AlZahra'a Alatraktchi
Fatima AlZahra'a Alatraktchi, born 1989 in Kuwait, is a Danish nanophysicist known for nanosensors that detect bacterial communication in patient samples in 30 seconds, and for founding the diagnostics start-up PreDiagnose.
Fatty acid ethyl ester
A fatty acid ethyl ester (FAEE) is an ester of a long-chain fatty acid and ethanol, produced mainly by transesterifying vegetable oils or animal fats with ethanol.
Fatty acid methyl ester
A fatty acid methyl ester (FAME) is an ester formed from vegetable oils, animal fats, or waste cooking oils with methanol; mixtures of FAME constitute biodiesel, the most widely produced oleochemical biofuel.
Fatty acids/isobutyric acid
Fatty acids/isobutyric acid (2-methylpropanoic acid, C4H8O2, CAS 79-31-2) is a short-chain branched fatty acid used as a grain and hay preservative; not EU-approved under Regulation 1107/2009 but JECFA-cleared as a flavouring.
Fatty alcohol
A fatty alcohol is a long-chain aliphatic alcohol with a terminal hydroxyl group and 8 to over 38 carbons, used to make detergents, surfactants, and cosmetics.
Fatty alcohols/aliphatic alcohols
Fatty alcohols, also called long-chain or aliphatic alcohols, are linear C6-C22 primary alcohols made from fats and oils or petrochemicals via Ziegler, Oxo, and hydrogenation, used in surfactants, cosmetics, and detergents.
Fatty aldehyde
A fatty aldehyde is an aldehyde formed from a fatty acid, with the carbonyl group at one end of the carbon chain, occurring in lipid metabolism and fragrances.
Faujasite
Faujasite is a rare natural zeolite mineral whose FAU framework, the most open of any natural zeolite, is shared with synthetic zeolites X and Y, used in catalysis.
Fault (geology)
A fault is a fracture in rock along which the two sides have moved relative to each other, and it is the primary source of earthquakes.
Fault scarp
A fault scarp is a step in the ground surface caused by slip on a fault, formed when earthquake rupture breaks through to the surface, and serves as primary evidence of past earthquakes.
Fault tree analysis
Fault tree analysis, also called failure tree analysis, is a deductive risk analysis method that links an undesired top event to combinations of component failures using Boolean logic gates.
Fault-tolerant quantum computation
Fault-tolerant quantum computation (FTQC) designs quantum computers so arbitrarily long computations run accurately despite noisy qubits, gates, and measurements, combining error-correcting codes with the threshold theorem.
Fausto Acernese
Fausto Acernese, born in Avellino, Italy, in 1975, is an Italian experimental physicist and associate professor at the University of Salerno working on Virgo gravitational-wave detection.
Favorskii rearrangement
The Favorskii rearrangement, described by Alexei Favorskii in the 1890s, is an organic reaction in which a base converts an α-halo ketone into a carboxylic acid derivative, ester, or amide.
Fayalite
Fayalite is the iron-rich end-member of the olivine group of nesosilicate minerals, with formula Fe₂SiO₄, forming a solid-solution series with forsterite that defines natural olivine.
FCHL representation
The FCHL representation, short for Faber–Christensen–Huang–Lilienfeld, is a fixed numerical descriptor of atomic environments used in kernel-based quantum machine learning models that predict molecular energies and forces.
Fe-doped nickel oxyhydroxide oxygen evolution catalysts
Fe-doped nickel oxyhydroxide (Ni(Fe)OOH, Ni1-xFexOOH) is a nickel oxyhydroxide electrocatalyst containing incorporated iron atoms, and the most active earth-abundant catalyst known for the oxygen evolution reaction in alkaline media.
Fe(PDP) C–H oxidation
Fe(PDP) C–H oxidation is a catalytic method for selectively oxidizing unactivated aliphatic C–H bonds, reported in 2007 by the White group at the University of Illinois Urbana-Champaign.
Fe3GaTe2
Fe3GaTe2 is a layered van der Waals ferromagnet, reported in 2022, that stays magnetic above room temperature and shows strong perpendicular anisotropy, making it a leading candidate for spintronic devices.
Fe3GeTe2
Fe3GeTe2 (FGT) is a layered van der Waals itinerant ferromagnet with a bulk Curie temperature near 220 K, which ionic gating raises to room temperature in thin flakes.
Fe3Sn2
Fe3Sn2 is a ferromagnetic iron-tin kagome metal whose bilayer lattice hosts massive Dirac fermions, a flat band, and an anomalous Hall effect about 20 times larger than in iron.
Fe5GeTe2
Fe5GeTe2, often written F5GT, is a layered metallic van der Waals ferromagnet in which Fe-Ge sheets sit between tellurium layers, with a Curie temperature near room temperature.
Feasible generalized least squares
Feasible generalized least squares (FGLS) is a two-step regression estimator that first estimates the error covariance matrix from least squares residuals, then applies generalized least squares.