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Raytheon Sentinel
The Raytheon Sentinel R1, also known as the Bombardier Sentinel, was a British RAF ground-surveillance aircraft based on the Bombardier Global Express, serving from 2007 to 2021.
Razer Inc. (ΛZΞR)
Razer Inc. is a gaming hardware company founded in 2005, known for gaming mice, keyboards, headsets, and Blade laptops, headquartered in Irvine, California and Singapore.
Razor
A razor is a bladed tool used to shave, cutting hair off at skin level. Types include the straight razor, safety and cartridge razors, and the electric razor.
Razrez Kharanorskiy
Razrez Kharanorskiy (Разрез «Харанорский») is a large open-pit brown-coal mine in Zabaykalsky Krai, Russia, and the main fuel supplier for power generation in the Trans-Baikal region.
Razrez Tugnuisky
Razrez Tugnuisky is a Russian open-pit coal mining company owned by SUEK that operates the Tugnuisky and Nikolsky mines in Buryatia, exporting low-sulfur coal mainly to Japan and China.
RB199
The RB199 is a three-shaft afterburning turbofan developed by the European consortium Turbo-Union to power the Panavia Tornado, entering service in 1979 with 2,504 engines delivered.
RBL 7-inch Armstrong gun
The RBL 7-inch Armstrong gun was a British rifled breech-loading gun designed by William Armstrong and built at Elswick, entering service in 1860 as the 100-pounder.
RBMK (РБМК)
The RBMK (РБМК), or high-power channel reactor, is a Soviet-designed water-cooled, graphite-moderated power reactor, first started in 1973 and involved in the 1986 Chernobyl disaster.
RBS-15
The RBS-15 (Robotsystem 15) is a Swedish long-range anti-ship missile developed by Saab and produced with Diehl Defence, with a range of more than 200 km.
RC circuit
An RC circuit, also known as an RC network or RC filter, combines a resistor and capacitor; its time constant τ = RC governs charging, filtering, and timing.
RC4
RC4 (Rivest Cipher 4) is a stream cipher designed by Ron Rivest of RSA Data Security in 1987, used in TLS, WEP, and WPA before its 2015 prohibition.
RCA 1802
The RCA 1802, also sold as the CDP1802 and known as the COSMAC, is an 8-bit CMOS microprocessor introduced by RCA in 1976, used in NASA's Galileo Jupiter orbiter.
RCA connector
The RCA connector, also called the phono plug, is a coaxial plug for analog audio and composite video, introduced by RCA in the 1930s for connecting turntables.
RCA Corporation
RCA Corporation (Radio Corporation of America) was an American electronics and media company, operating 1919–1986. It dominated U.S. radio and TV manufacturing and owned the NBC network.
RCS reference model
The RCS reference model, developed at NIST beginning in the mid 1970s, is a hierarchical architecture for real-time intelligent control, applied to robotics, manufacturing, and autonomous vehicles.
RD-170
The RD-170 is a Soviet liquid-oxygen and kerosene rocket engine made by NPO Energomash in Moscow, powering Energia strap-on boosters and the Zenit first stage from 1985.
RD-180
The RD-180 (РД-180) is a Russian liquid oxygen and kerosene rocket engine developed by NPO Energomash that has powered the first stage of the Atlas V since 2002.
RD-214
The RD-214 (GRAU index 8D59) was a Soviet four-chamber liquid-propellant engine developed by Valentin Glushko's bureau to power the first stage of the R-12 missile and the Kosmos-2 launcher.
RDC (resolver-to-digital converter)
An RDC, or resolver-to-digital converter, is a circuit or algorithm that converts a resolver's analog sine and cosine signals into digital shaft angle and speed.
RDF Schema
RDF Schema (RDFS) is a W3C Recommendation providing a data-modeling vocabulary for RDF, defining classes, properties, and their relationships through mechanisms like domain and range.
RDF/XML
RDF/XML is an XML syntax for serializing Resource Description Framework (RDF) graphs, the triple-based data model underlying the Semantic Web. First standardized in 1999, it remains in active use.
RDFa
RDFa (Resource Description Framework in Attributes) is a W3C specification that embeds machine-readable RDF data in HTML, XHTML, SVG, and XML documents by adding attributes to existing markup elements.
RDK (Karlsruhe) power station
The RDK (Karlsruhe) power station, formally the Rheinhafen-Dampfkraftwerk, is a power plant complex on the Rhine harbor in Karlsruhe, Germany, operated by EnBW with 1,811 MW capacity.
RDMA over Converged Ethernet
RDMA over Converged Ethernet (RoCE) is a protocol developed by the InfiniBand Trade Association that carries RDMA traffic over Ethernet, letting adapters access remote memory without CPU involvement.
RDNA (microarchitecture)
RDNA, or Radeon DNA, is an AMD graphics microarchitecture family introduced in 2019 as the successor to GCN, powering Radeon RX 5000 through 9000 Series cards and the PlayStation 5 and Xbox Series consoles.
RDNA 4
RDNA 4 is a gaming-focused GPU architecture from AMD, announced February 28, 2025, as the fourth generation of the RDNA line and the basis of the Radeon RX 9000 Series cards.
RDS-1 (РДС-1)
RDS-1 (РДС-1), American codename Joe-1, was the first Soviet atomic bomb, a copy of the Fat Man design detonated on 29 August 1949 at Semipalatinsk, ending the US nuclear monopoly.
RDT-1B
RDT-1B is a 1B-parameter diffusion transformer for bimanual robot manipulation, released in October 2024 by Tsinghua University's TSAIL group and described as the largest such model at the time.
RDX
RDX, also called cyclonite or cyclotrimethylenetrinitramine, is a white crystalline nitramine high explosive, about 1.5 times as powerful as TNT and second only to it in military use.
RE-Bench
RE-Bench (Research Engineering Benchmark) is a benchmark from METR, released in November 2024, that scores AI agents and human experts on 7 open-ended machine-learning research-engineering tasks.