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Rebecca Schulman
Rebecca Schulman is a professor of chemical and biomolecular engineering at Johns Hopkins University whose lab programs DNA circuits and self-assembling nanostructures to compute and actuate soft materials.
Rebellions
Rebellions is a South Korean fabless semiconductor company that designs AI inference accelerators, formed by the December 2024 merger with SAPEON Korea and valued at about $2.34 billion in 2026.
Rebels Motorcycle Club
The Rebels Motorcycle Club (Rebels MC) is an outlaw motorcycle club founded in Brisbane, Australia, in 1969, described as Australia's biggest, with chapters in about 20 countries.
Rebreather
A rebreather is a breathing apparatus that recycles exhaled gas by scrubbing carbon dioxide and replenishing oxygen instead of venting breaths, used in diving, mine rescue, firefighting, and anesthesia systems.
REC Group
REC Group is a solar panel manufacturer founded in 1996 in Oslo, Norway, with operational headquarters in Singapore, and wholly owned by Reliance Industries since 2021.
Rec. 2020
Rec. 2020, formally Recommendation ITU-R BT.2020, is the ITU standard defining pixel counts, frame rates, and colorimetry for 4K and 8K ultra-high definition television, approved in August 2012.
Rec. 709
Rec. 709, formally Recommendation ITU-R BT.709, is the international standard for high-definition television production and program exchange, first agreed in 1993 and the basis of sRGB.
ReCAPTCHA
reCAPTCHA is a CAPTCHA system that tells humans from bots, created by Luis von Ahn at Carnegie Mellon in 2007 and acquired by Google in 2009.
Received signal strength indicator
Received signal strength indicator (RSSI) is a figure reported by a radio receiver's physical layer representing total power observed at the antenna, used in Wi-Fi and other radio standards.
Receiver autonomous integrity monitoring
Receiver autonomous integrity monitoring (RAIM) is a self-contained algorithm in a satellite navigation receiver that checks the consistency of redundant pseudorange measurements and warns when integrity fails.
Recessed light
A recessed light, also called a can light, pot light, or downlight, is a light fixture installed fully above the ceiling plane, pioneered commercially in the late 1940s.
Recharge (trade association)
Recharge, formally RECHARGE aisbl, is a Brussels-based trade association founded in 1998 representing the European advanced rechargeable and lithium battery industry, from raw-material suppliers to manufacturers and recyclers.
Rechargeable battery
A rechargeable battery, also known as a secondary cell, is a battery designed to be electrically recharged. Lithium-ion versions power electric vehicles and grid storage.
Rechargeable zinc–manganese dioxide battery
A rechargeable zinc–manganese dioxide battery pairs metallic zinc with a manganese dioxide cathode in aqueous electrolyte; Kang and co-workers proposed the modern rechargeable design in 2011.
Reciprocal rank fusion
Reciprocal rank fusion (RRF) is an unsupervised method that merges ranked result lists from several search systems into one ranking by summing reciprocal ranks, introduced in 2009.
Reciprocating compressor
A reciprocating compressor is a positive-displacement machine that raises gas pressure with pistons and valves, serving as one of four essential components of vapor compression refrigeration systems.
Reciprocating engine
Defined by pistons moving in cylinders to convert pressure into rotational motion, the reciprocating engine dominates land transport and powers roughly 99 percent of global transport.
Reciprocating saw
A reciprocating saw, often called a Sawzall or recip saw, is a handheld power saw that cuts wood, metal, and plastic with a rapid back-and-forth blade stroke.
Reciprocating tribometer
A reciprocating tribometer is a laboratory instrument that measures friction and wear between surfaces sliding back and forth under load, commonly a ball on a flat, standardized as ASTM G133.
Reciprocity calibration (massive MIMO)
Reciprocity calibration (massive MIMO) compensates transmit and receive hardware mismatches in a TDD massive MIMO base station, letting it steer downlink beams from uplink pilots without feedback.
Reckless driving
Reckless driving is a traffic offense in which a driver acts with willful or wanton disregard for safety, a mental state above ordinary negligence, defined differently across US states.
Reclaimed asphalt pavement
Reclaimed asphalt pavement (RAP) is crushed and screened old asphalt pavement, reused in new asphalt mixes; the United States reused over 101 million tons in 2024.
Reclaimed asphalt shingles
Reclaimed asphalt shingles are processed roofing shingles from manufacturing scrap or residential tear-offs, ground and added to asphalt paving mixtures, supplying up to 20 percent of the mix's binder.
Reclaimed rubber
Reclaimed rubber is rubber made by converting scrap vulcanized rubber, mostly from worn tires, into a processible material that can be vulcanized again with sulfur.
Reclaimed water
Reclaimed water, also known as recycled water or wastewater reuse, is water from sinks, showers, and industry that is treated and used again for irrigation, industrial supply, or even drinking water.
Recloser
A recloser is an automatic switching device on electric power lines that interrupts fault current and recloses to test whether the fault has cleared, locking open if it persists.
Reclosing
Reclosing, also called automatic reclosing or auto-reclose, automatically re-closes a tripped circuit breaker in power systems, restoring service after temporary overhead-line faults such as lightning strikes.
Recode
Recode is the name of several unrelated software products and technical terms, best known as a technology news site founded by Kara Swisher and Walt Mossberg.
Recoil mechanism
A recoil mechanism is the gun assembly that absorbs the rearward force of firing and returns the barrel to position, first fielded on the French 75 mm gun of 1897.
Recoil operation
Recoil operation is a firearm operating principle in which the gun's own recoil cycles the action, first put to practical use in Hiram Maxim's 1884 machine gun.