42,772 articles
Flavour-changing neutral current
A flavor-changing neutral current (FCNC) is a rare particle interaction in which a quark changes flavor without changing its electric charge, such as beauty to strange.
Fleet Numerical Meteorology and Oceanography Center
The Fleet Numerical Meteorology and Oceanography Center (FNMOC) is the United States Navy's operational numerical weather prediction center, dual-located in Monterey, California, and Stennis Space Center, Mississippi.
Fleet Survey Team (United States Navy)
The Fleet Survey Team is a deployable U.S. Navy hydrographic unit, commissioned in 2005 under the Naval Oceanographic Office, that surveys littoral waters, ports, and landing beaches.
Fleiss' kappa
Fleiss' kappa is a chance-corrected statistic measuring agreement among three or more raters classifying the same items into nominal categories, introduced by Joseph L. Fleiss in 1971.
Fleming's left-hand rule for motors
Fleming's left-hand rule for motors is a mnemonic giving the direction of the force on a current-carrying wire in a magnetic field, devised by John Ambrose Fleming.
Fleming's right-hand rule
Fleming's right-hand rule, also called the generator or dynamo rule, is a mnemonic giving the direction of current induced in a conductor moving through a magnetic field.
Flemming Besenbacher
Flemming Besenbacher (born 1952) is a Danish nanoscientist at Aarhus University known for scanning tunnelling microscopy of catalysts, who also chaired the Carlsberg Group from 2012 to 2022.
Flerovium
Flerovium, formerly called ununquadium, is a synthetic superheavy chemical element with symbol Fl and atomic number 114, first produced in 1998 at JINR in Dubna, Russia.
Flexible metal–organic frameworks
Flexible metal–organic frameworks (FMOFs), also called soft porous crystals, are porous crystalline solids that reversibly open and close their pores, or breathe, in response to guests, pressure, temperature, or light.
Flexoelectricity
Flexoelectricity is an electromechanical coupling in which a gradient of mechanical strain induces electric polarization, and conversely an electric field gradient induces stress; unlike piezoelectricity, it occurs in all dielectrics.
Flexural strength
Flexural strength, also called modulus of rupture or bending strength, is the maximum stress a material's outer surface sustains before it yields or fractures in a bending test.
Flicker fusion threshold
The flicker fusion threshold, or critical flicker fusion frequency, is the frequency at which a flashing light appears continuous, a standard measure of visual temporal resolution.
Flight
Flight is the sustained motion of an object through the air, achieved when aerodynamic or buoyant forces counteract weight; heavier-than-air machines rely on lift, weight, thrust, and drag.
Flint
Flint is a hard, dark sedimentary rock made of microcrystalline quartz, occurring as nodules in chalk, whose conchoidal fracture gives razor-sharp edges prized for prehistoric tools and fire starting.
Flip clock
A flip clock is a clock that displays time with printed cards or flaps that mechanically flip over each minute, best known through Solari's split-flap system.
Flipped classroom
The flipped classroom, also called flipped learning, is a pedagogical model in which students learn material before class and class time is spent on active practice and problem-solving.
Float (oceanography)
In oceanography, a float is an autonomous free-drifting instrument that sinks to a set depth and profiles temperature and salinity, transmitting data by satellite when it surfaces; about 4,000 are operated by the international Argo program.
Float glass
Float glass is flat glass made by floating molten glass on a bath of molten tin, developed by Alastair Pilkington at Pilkington Brothers between 1952 and 1959.
Floating car data
Floating car data (FCD) is traffic measurement in which vehicles or travelers' devices report position, direction, and speed, so the moving vehicles themselves act as traffic sensors.
Floating catalyst chemical vapor deposition
Floating catalyst chemical vapor deposition (FCCVD, also called aerosol CVD) is a technique where catalyst nanoparticles float in the gas stream, so carbon nanotubes grow airborne and are collected continuously as films, yarns, and aerogels.
Floating island
A floating island is a buoyant mass of vegetation, peat, or other material resting on a lake's surface, occurring naturally in wetlands and built deliberately for water treatment.
Flocculation
Flocculation is the process in which small suspended particles in a liquid are joined into larger aggregates, called flocs, big enough to settle or be filtered out.
Floer homology
Floer homology is an infinite-dimensional analog of Morse homology introduced by Andreas Floer around 1986, giving invariants in symplectic topology and of 3-manifolds and knots.
Flood
A flood is an excess of water on normally dry land, caused by overflowing rivers, heavy rain, snowmelt, or dam failure, and is the most common weather-related disaster.
Flood basalt
A flood basalt, also called plateau basalt, is a massive outpouring of basaltic lava from fissures that covers vast areas; examples include the Deccan and Siberian Traps.
Flood fill
Flood fill is an algorithm that repaints the connected region of same-colored cells around a seed cell in a grid or image, as in a paint bucket tool.
Flood frequency analysis
Flood frequency analysis is a statistical method relating flood magnitude at a river or coastal site to its annual exceedance probability, used in drainage design and dam safety.
Flood inundation mapping
Flood inundation mapping is the geospatial technique that maps the extent and depth of floodwater, using hydraulic models, satellite imagery, or terrain analysis, producing extent maps and depth grids.
Flood pulse
The flood pulse is the periodic inundation and drying of a river's floodplain. The 1989 Flood Pulse Concept by Junk, Bayley, and Sparks holds it drives river-floodplain productivity.
Flood risk mapping
Flood risk mapping is a geospatial method that identifies flood-prone areas and combines modeled flood extent with exposure data to support land-use planning, insurance rating, and flood risk management.