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Oldroyd-B model
The Oldroyd-B model is a three-parameter constitutive equation for the viscoelastic stress of dilute polymer solutions, introduced by J. G. Oldroyd in 1950 and widely used for Boger fluids.
Ole Lamm
Ole Lamm (1902–1964) was a Swedish physical chemist, professor at KTH, who derived the 1929 Lamm equation governing sedimentation, still central to protein analysis by ultracentrifugation.
Ole Rømer
Ole Rømer, also known as Ole Christensen Rømer or Olaus Roemer, was a Danish astronomer who in 1676 first demonstrated observationally that light travels at a finite speed.
Oleandomycin
Oleandomycin is a macrolide antibiotic produced by the soil bacterium Streptomyces antibioticus, isolated in 1954 at Pfizer, marketed as Matromycin and Romicil, and active against gram-positive bacteria.
Oleanolic acid
Oleanolic acid is a naturally occurring pentacyclic triterpenoid found widely in food plants and medicinal herbs, especially olives, and studied for liver-protective, anti-inflammatory, antidiabetic, and anticancer activities.
Olefin isomerization
Olefin isomerization is the catalytic rearrangement of an alkene without changing its molecular formula, most often by double-bond migration or interconversion of E and Z isomers.
Olefin metathesis
Olefin metathesis, also called alkene metathesis, is a catalytic reaction in which two alkenes exchange the groups around their double bonds, used widely in organic synthesis and polymer chemistry.
Olefin oligomerization
Olefin oligomerization is the catalytic joining of a few alkene molecules, most often ethylene, into short chains, the dominant industrial route to linear alpha olefins used in detergents, lubricants, and polyethylene.
Oleg D. Jefimenko
Oleg D. Jefimenko (1922–2009) was an American physicist at West Virginia University known for Jefimenko's equations and for electrostatic motors powered by the earth's atmospheric electric field.
Oleg Lavrentiev
Oleg Lavrentiev (Олег Лаврентьєв) was a Soviet and Ukrainian physicist whose 1950 letter from Sakhalin proposed a hydrogen bomb design and inspired Sakharov's fusion work, leading to the tokamak.
Oleg Lavrentovich
Oleg D. Lavrentovich, born 1958, is a Ukrainian-born soft-matter physicist at Kent State University known for work on topological defects, nonlinear electrophoresis, and ferroelectric nematics.
Oleg V. Ozerov
Oleg V. Ozerov is an organometallic chemist at Texas A&M University known for pincer-ligand catalysis and carbon–fluorine bond activation, recognized by the 2012 ACS Award in Pure Chemistry.
Oleg V. Prezhdo
Oleg V. Prezhdo, also published as Oleg Prezhdo, is a Ukrainian-born theoretical chemist at USC known for surface-hopping methods and the PYXAID code for solar materials.
Oleg Yurievich Gusikhin
Oleg Yurievich Gusikhin is a Ford Motor Company data scientist and operations researcher who works on supply chain analytics and was elected to the National Academy of Engineering in 2026.
Oleic acid
Oleic acid, or cis-9-octadecenoic acid, is a monounsaturated 18-carbon fatty acid and the principal fatty acid of olive oil, making up 63–80% of its fats.
Oleksandr Sharkovsky
Oleksandr Mykolaiovych Sharkovsky (Олександр Миколайович Шарковський; 1936–2022) was a Ukrainian mathematician, academician of the National Academy of Sciences of Ukraine, best known for Sharkovsky's theorem.
Olester Benson Jr.
Olester Benson Jr. is a retired American chemist and Corporate Scientist at 3M who holds 89 United States patents and is elected to the National Academy of Engineering.
Oleum
Oleum, also known as fuming sulfuric acid or Nordhausen acid, is a solution of sulfur trioxide in sulfuric acid that fumes strongly and reacts violently with water.
Oleuropein
Oleuropein is a phenolic secoiridoid glycoside in olives and olive leaves, responsible for their bitterness and studied as a supplement whose health benefits remain unproven.
Oleyl alcohol
Oleyl alcohol is an unsaturated long-chain fatty alcohol, (Z)-9-octadecen-1-ol, a pale yellow oily liquid made by reducing oleic acid and used chiefly as a cosmetic emollient.
Oleylamine
Oleylamine, the cis isomer of 9-octadecenylamine, is an unsaturated C18 long-chain primary amine that stays liquid at room temperature and is widely used in nanocrystal synthesis as ligand, solvent, and reducing agent.
Olfactometry
Olfactometry measures odor by presenting controlled dilutions of a vapor sample to trained human assessors, converting perception into an odor concentration measured in odor units.
Olga Bondareva
Olga Nikolaevna Bondareva is a Soviet mathematician who proved the Bondareva–Shapley theorem, the balancedness condition for a cooperative game to have a non-empty core, in Leningrad in 1962 and 1963.
Olga Ladyzhenskaya (Ольга Александровна Ладыженская)
Olga Ladyzhenskaya (Ольга Александровна Ладыженская), born 1922 and died 2004, was a Russian mathematician known for proving global unique solvability of the 2D Navier-Stokes equations.
Olga Smirnova (theoretical physicist)
Olga Smirnova (Ольга Смирнова) is a theoretical physicist who leads the Strong Field Theory Group at the Max Born Institute in Berlin and works on attosecond physics.
Olga Taussky-Todd
Olga Taussky-Todd (1906–1995) was an Austrian-born mathematician who made matrix theory an independent branch of mathematics, publishing nearly 300 papers and becoming the first woman full professor at Caltech in 1971.
Oligarchic growth
Oligarchic growth is a stage of planet formation, following runaway growth, in which similar-sized planetary embryos slowly accrete planetesimals from their own feeding zones while keeping nearly fixed orbital separations.
Oligocene
The Oligocene, from 33.9 to 23.03 million years ago, is the youngest epoch of the Paleogene Period, marked by global cooling, Antarctic ice sheet growth, and major mammal turnovers.
Oligodynamic effect
The oligodynamic effect, or oligodynamic action, is the biocidal action of trace metal ions against bacteria, fungi, and viruses, described by Carl von Nägeli in 1893.
Oligomer
An oligomer is a molecule of intermediate molecular mass made of a few units from smaller molecules, sitting between small molecules and polymers, with two units forming a dimer.