All articles starting with R
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Ring size
A ring size is a standardized designation of a ring's inner dimensions, defined by ISO 8653 as the circumference of the largest cylinder that fits inside the ring.
Ring strain
Ring strain is the extra energy in a molecule forced away from ideal bond angles and lengths, explaining why small rings like cyclopropane are unstable and reactive.
Ring system
A ring system is a disk of small particles orbiting a planet in a common plane. All four giant planets of the solar system have known rings.
Ring test
A ring test, also called a ring trial or round robin, is an interlaboratory comparison in which identical samples are analyzed and scored against an assigned value.
Ring theory
Ring theory is the branch of algebra that studies rings, sets with addition and multiplication obeying basic axioms, with commutative and noncommutative branches and examples like the integers.
Ring Two (1999 film)
Ring 2 (リング2, Ringu 2) is a 1999 Japanese horror sequel directed by Hideo Nakata to Ring (1998), written by Hiroshi Takahashi, starring Miki Nakatani; it replaced Rasen as the canonical sequel and outgrossed the first film.
Ring vaccination
Ring vaccination (surveillance and containment) vaccinates contacts and contacts-of-contacts around each index case rather than whole populations. Pivotal in smallpox eradication (Foege, 1967) and the recommended Ebola vaccine delivery strategy; needs strong contact tracing.
Ring Video Doorbell
The Ring Video Doorbell is a smart doorbell with a camera that streams live video and alerts to a phone, created by Jamie Siminoff in 2012.
Ring Virus (링)
Ring Virus (링), also The Ring Virus, is a 1999 South Korean horror film directed by Kim Dong-bin, the first Korean-Japanese capital co-production, remaking Nakata's Ring from Suzuki Koji's novel; it earned 332,354 Seoul admissions.
Ring-closing metathesis
Ring-closing metathesis (RCM) is an olefin metathesis reaction in which a metal carbene catalyst converts a diene into a cycloalkene, from five-membered rings to macrocycles, driving much natural product synthesis.
Ring-core fiber
Ring-core fiber is an optical fiber that guides light in a ring-shaped annulus of high refractive index instead of a solid core, built to carry twisted orbital angular momentum modes.
Ring-imaging Cherenkov detector
A ring-imaging Cherenkov detector, also known as a RICH detector, identifies charged particles by measuring the angle of the Cherenkov light cone they emit, which combines with momentum to give the particle's mass.
Ring-necked snake
Ring-necked snake (Diadophis punctatus), a small North American rear-fanged snake from southeastern Canada to northern Mexico; dark back, bright orange-red venter, tail-coil startle display, mild Duvernoy's gland venom, 2–10 eggs, IUCN least concern.
Ring-opening metathesis
Ring-opening metathesis, also called ring-opening cross metathesis (ROCM), opens a strained cyclic alkene with a metal carbene and caps it with an external olefin to give an acyclic diene.
Ring-opening metathesis polymerization
Ring-opening metathesis polymerization (ROMP) is a chain-growth polymerization in which a metal-carbene catalyst opens the ring of a strained cyclic olefin to form an unsaturated polymer chain.
Ring-opening polymerization
Ring-opening polymerization (ROP) is a polymerization in which a cyclic monomer opens into a linear chain, driven by ring strain, producing polyesters, polyethers, and polyamides.
Ring-polymer instanton
The ring-polymer instanton is a computational method in theoretical chemistry, developed by Jeremy Richardson and Stuart Althorpe, that computes quantum tunneling rates and splittings of molecules.
Ring-tailed lemur
Ring-tailed lemur (Lemur catta): a ground-foraging, female-dominant primate of southern Madagascar with 13 black-and-white tail rings; IUCN Endangered, declining over 50% in three generations.
Ringatū
Ringatū is a Māori Christian faith, meaning "the upraised hand," founded by the prophet Te Kooti Arikirangi Te Tūruki in exile on the Chatham Islands in the 1860s.
Ringback tone
A ringback tone, also called ringing tone or audible ringing tone, is the sound a caller hears while the called party's telephone is being alerted, generated by the network.
RingCentral
RingCentral is an American provider of cloud-based business communications software, founded in 1999 by Vlad Shmunis and Vlad Vendrow and headquartered in Belmont, California. Its offerings include unified communications, contact center, and video services.
Ringdown
Ringdown is a telephony signaling method in which ringing current alerts an operator or called station without dialing; ringdown circuits connect two endpoints directly, so lifting the handset rings the far end.
Ringed hair disease
Ringed hair disease (pili annulati, OMIM 180600) is a rare benign autosomal dominant hair shaft disorder with alternating light and dark bands from air-filled cortical cavities, mapped to chromosome 12q24.32–24.33, usually without fragility.
Ringedals Dam
Ringedals Dam (Ringedalsdammen) is a concrete gravity dam at the head of Ringedalsvatnet in Skjeggedal, above Tyssedal in Vestland, Norway. Built 1910–1918 for the Tysso I hydroelectric plant, it was Norway's largest dam when completed.
Ringel rangel
Ringel Rangel is a 1993 Haba children's dexterity board game by Swiss designer Geni Wyss, for 2-4 players aged 4+, in which players finger-push wooden turtles to colored rings; it won the 1993 Spiel des Jahres Kinderspiel special prize. Unrelated to the rondel mechanic.
Ringel's conjecture
Ringel's conjecture is a 1963 graph theory conjecture stating that every tree with n edges decomposes the complete graph K(2n+1); it was proved for all sufficiently large n in 2021.
Ringer (TV series)
Ringer (TV series): American CW serialized crime drama (2011), created by Eric Charmelo and Nicole Snyder, starring Sarah Michelle Gellar as twin sisters Bridget and Siobhan in an identity-swap thriller; one season, now on Netflix and Prime Video.
Ringer's lactate solution
Ringer's lactate solution (Hartmann's solution, compound sodium lactate) is a balanced isotonic IV crystalloid with sodium ~130 mmol/L, potassium, calcium, and lactate buffer, used for resuscitation, burns, and critical care.
Ringhals nuclear power plant
Ringhals is a Swedish nuclear power plant on the Värö peninsula, about 60 kilometers south of Gothenburg, where two pressurized water reactors produce around 17 TWh per year.
Ringhorne oil field
Ringhorne is an oil field in the Norwegian sector of the North Sea, in the southern Viking Graben, producing since 2003 from a platform and operated by Vår Energi.