42,772 articles
Nylon 11
Nylon 11, or polyamide 11 (PA11), is a thermoplastic polyamide derived from castor oil, first patented in France in 1947 and sold mainly as Rilsan.
Nylon 12
Nylon 12, also known as polyamide 12 or PA12, is an oil-based semi-crystalline polyamide thermoplastic known for low water absorption and use in automotive fuel lines.
Nylon 6
Nylon 6, also known as polyamide 6 (PA6) or polycaprolactam, is a thermoplastic polyamide made by ring-opening polymerization of caprolactam, used as a fiber and molding resin.
Nylon 66
Nylon 66 (Polyamide 6,6) is a synthetic polyamide made from adipic acid and hexamethylenediamine, first synthesized at DuPont in 1935 and used in textiles, air bags, and automotive parts.
Nylon depolymerization
Nylon depolymerization is the chemical recycling of nylon, breaking polyamide polymers back into monomers like ε-caprolactam for purification and repolymerization into virgin-quality plastic, a process used industrially since the 1990s.
Nylon recycling
Nylon recycling is the recovery of polyamide (nylon) waste through mechanical, chemical, solvent-based, or biological processes that return it to usable polymer or monomers such as caprolactam.
Nyquist stability criterion
The Nyquist stability criterion is a graphical test that determines whether a closed-loop feedback system is stable by counting encirclements of −1, introduced by Harry Nyquist in 1932.
Nyquist–Shannon sampling theorem
The Nyquist–Shannon sampling theorem, also called the Nyquist theorem, states that a bandlimited signal can be perfectly reconstructed from samples taken at more than twice its highest frequency.
NYS Mesonet
The NYS Mesonet is a statewide network of over 200 automated weather stations operated by the University at Albany, established in 2014 with FEMA funding after Superstorm Sandy.
Nω-Nitro-L-arginine
Nω-Nitro-L-arginine (L-NNA, NOLA) is a synthetic derivative of L-arginine and one of the first inhibitors of nitric oxide synthase, extensively used in pharmacology research.
O p-band center descriptor
The O p-band center descriptor is the energy of an oxide's oxygen 2p band center relative to its Fermi level, used to predict catalytic activity of transition-metal oxides.
o-Anisidine
o-Anisidine (2-methoxyaniline) is an aromatic amine, a yellowish liquid used chiefly as an intermediate in azo dye manufacture, classified as probably carcinogenic to humans by IARC.
o-Carborane
o-Carborane (1,2-dicarba-closo-dodecaborane) is an icosahedral boron-carbon cluster with adjacent cage carbons, first synthesized from decaborane and acetylene in 1963 and used in drug design, materials, and boron neutron capture therapy.
o-Cresol
o-Cresol, also known as 2-methylphenol, is an organic compound with formula CH₃C₆H₄OH, one of the three cresol isomers, used as a disinfectant, solvent, and chemical intermediate.
o-minimality
O-minimality is a tameness condition in model theory requiring every definable set to be a finite union of points and intervals, introduced by van den Dries.
o-Nitrophenol
o-Nitrophenol, also called 2-nitrophenol, is an organic compound with formula C₆H₅NO₃, with nitro and hydroxyl groups adjacent on a benzene ring; its intramolecular hydrogen bond makes it more volatile than the para isomer.
O-Phenylenediamine
o-Phenylenediamine (benzene-1,2-diamine) is an aromatic diamine with two amino groups on adjacent positions of a benzene ring, used chiefly to make benzimidazole fungicides and pharmaceuticals.
O-Toluidine
O-Toluidine (ortho-toluidine, 2-methylaniline) is a light-yellow aromatic amine used to make rubber chemicals, herbicide intermediates, and dyes, classified as a known human carcinogen causing bladder cancer.
O-type main-sequence star
An O-type main-sequence star, also called a type O V star, is the hottest and most massive hydrogen-fusing star, with a blue surface above 30,000 K.
O-type star
An O-type star, or O star, is the hottest class of star in the spectral sequence, a rare, blue, extremely luminous star living only a few million years.
O–O bond formation in oxygen evolution
O–O bond formation in oxygen evolution is the step in water splitting where two oxygen atoms join into the O–O bond of O₂, typically the rate-determining step.
O. Anatole von Lilienfeld
O. Anatole von Lilienfeld, also known as Anatole von Lilienfeld, is a computational chemist at the University of Toronto known for machine learning models of molecular properties.
O(N) model
The O(N) model is a family of field theories with an N-component field whose critical point defines a central conformal field theory, spanning the Ising, XY, and Heisenberg universality classes.
O−C diagram
An O−C diagram, short for observed minus calculated, is an astronomy plot of timing residuals used to study period changes in variable stars and binary systems.
O3-type sodium layered oxide cathode
An O3-type sodium layered oxide cathode is a sodium-rich positive-electrode material for sodium-ion batteries with formula NaxMO2, where sodium sits in octahedral coordination and oxygen stacks in an ABCABC sequence.
O6-Methylguanine
O6-Methylguanine (O6-MeG) is a damaged DNA base formed when alkylating agents methylate guanine; it mispairs with thymine, causing G:C to A:T mutations, and is repaired by MGMT.
Oasis
An oasis is an area made fertile by freshwater from springs or wells in an otherwise arid region, supporting agriculture, settlement, and trade, such as Egypt's Nile valley.
Oaxaca–Blinder decomposition
The Oaxaca–Blinder decomposition is a statistical method that splits the mean difference between two groups, such as a wage gap, into explained and unexplained parts, introduced in 1973.
OB association
An OB association is a loose grouping of young O- and B-type stars, defined by Viktor Ambartsumian in 1947, that disperses within tens of millions of years.
Obduction
Obduction is the tectonic process by which dense oceanic lithosphere, typically preserved as an ophiolite, is thrust onto lighter continental lithosphere instead of sinking at subduction zones.