All articles starting with U
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Ultra Korea
Ultra Korea (울트라 코리아) is an electronic dance music festival in South Korea, first held in Seoul in 2012 as the Ultra brand's first Asian event.
Ultra large crude carrier
An ultra large crude carrier (ULCC) is an oil tanker of 320,000 tonnes deadweight or more, the largest crude-carrier class ever built, almost all of them constructed in the 1970s.
Ultra Low Emission Zone
The Ultra Low Emission Zone (ULEZ) is Transport for London's charging scheme for polluting vehicles, launched in central London in April 2019 and expanded London-wide in August 2023, charging £12.50 daily for non-compliant cars, vans, and motorcycles.
Ultra low frequency
Ultra low frequency (ULF) is the ITU radio band from 300 Hz to 3 kHz, with wavelengths of 1,000 to 100 km, used mainly for submarine and mine communications.
Ultra Music Festival
Ultra Music Festival (UMF) is an annual three-day electronic dance music festival held each March in Miami, Florida, co-founded in 1999 by Russell Faibisch and Alex Omes.
Ultra Music Festival 2017
Ultra Music Festival 2017, or UMF 2017, was the 19th edition of the Miami electronic dance music festival, held March 24–26, 2017 at Bayfront Park in Downtown Miami.
Ultra Music Festival Europe 2026
Ultra Music Festival Europe 2026 was the twelfth edition of the Ultra Europe electronic dance music festival, held 10–12 July 2026 in Split, Croatia, drawing a record 140,000 attendees.
Ultra Path Interconnect
Ultra Path Interconnect (UPI) is Intel's coherent point-to-point interconnect, introduced on July 11, 2017 with Xeon Scalable processors to connect multiple CPU sockets, replacing QuickPath Interconnect.
Ultra South Africa
Ultra South Africa is Africa's largest electronic music festival, a single-day Ultra Worldwide event held in Johannesburg and Cape Town since its 2014 debut, which drew 40,000 fans.
Ultra vires
Ultra vires (Latin, "beyond the powers") is the doctrine that acts exceeding a company's or public authority's granted powers are invalid; largely abolished in corporate law, still central in administrative law.
Ultra-deep sequencing
Ultra-deep sequencing is a next-generation DNA sequencing strategy that reads a targeted region or gene panel to coverage far beyond conventional recommendations, so rare variants can be separated from sequencing noise.
Ultra-diffuse galaxy
An ultra-diffuse galaxy (UDG) is a galaxy of dwarf-galaxy stellar mass but extremely large size and extremely low surface brightness, first named after 47 were found in the Coma cluster in 2015.
Ultra-distance cycling
Ultra-distance cycling (ultracycling): non-stop races of 500 km or more, 12/24-hour events, and randonneuring. Key events: Race Across America (4,933 km, 53,000 m climbing), Paris-Brest-Paris (1,200 km, since 1891), Transcontinental Race; Strasser's 896.173 km 24-h record.
Ultra-faint dwarf galaxy
An ultra-faint dwarf galaxy (UFD) is the least luminous, most dark matter-dominated type of galaxy known, first found in Sloan Digital Sky Survey data in 2005.
Ultra-high vacuum
Ultra-high vacuum (UHV) is the vacuum regime below about 10⁻⁶ Pa and down to 10⁻⁹ Pa, where molecules travel between chamber walls instead of colliding with each other.
Ultra-high-definition television
Ultra-high-definition television (UHDTV), also known as 4K/8K TV, is a digital television format with resolutions of 3840 × 2160 and 7680 × 4320 pixels, standardized by the ITU in 2012.
Ultra-high-energy cosmic ray
An ultra-high-energy cosmic ray (UHECR), also called an extreme-energy cosmic ray, is a proton or nucleus reaching Earth with up to about 50 joules of energy, and its origin remains unknown.
Ultra-high-molecular-weight polyethylene
Ultra-high-molecular-weight polyethylene (UHMWPE) is a polyethylene with molecular weight above 1 million g/mol, giving strength and wear resistance for artificial joints, body armor, and ropes.
Ultra-high-nickel cathodes
Ultra-high-nickel cathodes are layered lithium-ion battery cathode materials, such as NCM90 and NCM95, in which nickel accounts for at least 90 mol% of transition metals, delivering high capacity while reducing cobalt use.
Ultra-high-performance concrete
Ultra-high-performance concrete (UHPC) is a fiber-reinforced cementitious composite with compressive strength above 120 MPa and very low permeability. Developed as reactive powder concrete at Bouygues in 1993, it is used mostly in bridges.
Ultra-high-temperature ceramic matrix composites
Ultra-high-temperature ceramic matrix composites (UHTCMCs) combine an ultra-high-temperature ceramic matrix with carbon or silicon carbide fibers, designed for structural use above 1600 °C in hypersonic vehicles and rockets.
Ultra-high-temperature ceramics
Ultra-high-temperature ceramics (UHTCs) are refractory carbides, nitrides, and diborides of early transition metals with melting points above 3000 °C, developed for hypersonic nose tips, thermal protection systems, and nuclear applications.
Ultra-high-temperature processing
Ultra-high-temperature (UHT) processing, or aseptic processing, heats pumpable foods like milk to about 135–150 °C for seconds, then aseptically packages them, giving commercially sterile products that keep 6–12 months unrefrigerated.
Ultra-hot Jupiter
An ultra-hot Jupiter (UHJ) is a gas-giant exoplanet in an extremely close orbit whose dayside temperature exceeds about 2,200 K, hot enough to dissociate molecules.
Ultra-Humanite
Ultra-Humanite (Gerard Shugel), DC Comics supervillain created by Siegel and Shuster, debuting Action Comics #13 (June 1939) as Superman's first recurring foe; brain-transferring body-hopper, best known in albino ape form.
Ultra-local model
An ultra-local model is a control-theory device that replaces a plant's full mathematical model with a low-order local input-output relation estimated online, forming the basis of model-free control.
Ultra-low emission retrofit (China)
An ultra-low emission retrofit in China upgrades coal-fired power units to meet emission limits as tight as gas turbines; over 95% of units completed it by 2023.
Ultra-low-field MRI
Ultra-low-field MRI (ULF MRI) is magnetic resonance imaging at field strengths far below conventional clinical scanners, trading image resolution for lower cost, portability, and use outside shielded rooms.
Ultra-low-loss fiber
Ultra-low-loss fiber is single-mode optical fiber engineered to cut attenuation to about 0.15 to 0.17 dB/km at 1550 nm, used chiefly in transoceanic submarine cables to lengthen amplifier spacing.
Ultra-low-sulfur diesel
Ultra-low-sulfur diesel (ULSD) is diesel fuel with sulfur limited to 15 ppm, required for US highway diesel since 2006's phase-in and for all highway use after 2010.