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Ruddlesden–Popper perovskite solar cells
Ruddlesden–Popper perovskite solar cells use a layered two-dimensional perovskite light absorber whose bulky organic cations improve stability against moisture, heat, and light at some cost to efficiency.
Rudolf Anderson
Rudolf Anderson Jr. was a US Air Force major and U-2 reconnaissance pilot killed by a Soviet missile over Cuba in 1962, the crisis's only combat fatality.
Rudolf Diesel
Rudolf Diesel, born Rudolf Christian Karl Diesel, was a German engineer who invented the diesel engine, first run in 1897, before vanishing at sea in 1913.
Rudolf E. Kálmán
Rudolf E. Kálmán (1930–2016) was a Budapest-born engineer and mathematician who invented the Kalman filter, used in Apollo navigation and GPS, and founded modern control theory.
Rudolf Knietsch
Rudolf Knietsch (1854–1906) was a German chemist at BASF who made the contact process for sulfuric acid work industrially and in 1888 developed the industrial liquefaction of chlorine.
Rudolf Kompfner
Rudolf Kompfner (1909–1977) was an Austrian-born physicist and engineer who invented the traveling-wave tube and the backward-wave oscillator, and led early communication-satellite work at Bell Laboratories.
Rudolf M. Tromp
Rudolf M. Tromp (R. M. Tromp) is a Dutch-born physicist at IBM's T.J. Watson Research Center, known for low-energy electron microscopy and elected to the National Academy of Engineering in 2020.
Rudolph Bonaparte
Rudolph Bonaparte is an American geotechnical engineer, chairman of Geosyntec Consultants in Atlanta, elected to the National Academy of Engineering in 2007 for landfill waste-containment design.
Rudong LNG Terminal
The Rudong LNG Terminal is a liquefied natural gas import terminal in Rudong County, Jiangsu, China, operated by PetroChina and receiving its first cargo in 2011.
Ruf Automobile
Ruf Automobile GmbH, the German manufacturer founded in Pfaffenhausen, Bavaria, in 1939, began with Porsche-based conversions and became certified in 1981, best known for the 1987 CTR Yellowbird.
Ruf CTR
The Ruf CTR, also known as the Ruf CTR Yellowbird, is a twin-turbo sports car built by Ruf Automobile of Pfaffenhausen, Germany, from 1987 on a Porsche 911 shell.
Rufus (software)
Rufus, the Reliable USB Formatting Utility, is a free open-source Windows tool by Pete Batard that creates bootable USB installation media from ISO images, including Windows 11.
Rugby Locomotive Testing Station
The Rugby Locomotive Testing Station, also known as Rugby Testing Centre, was a plant in Rugby, England, where steam locomotives were tested on rollers, opened in 1948.
Ruger 10/22
The Ruger 10/22 is a semi-automatic rimfire rifle in .22 Long Rifle made by Sturm, Ruger & Co. since 1964, known for its 10-round rotary magazine.
Ruger Blackhawk
The Ruger Blackhawk is a single-action, six-shot revolver introduced in 1955 by Sturm, Ruger & Co. as its first centerfire handgun, styled after the Colt Single Action Army.
Ruger M77
The Ruger M77, also known as the Ruger Model 77, is a bolt-action hunting rifle made by Sturm, Ruger & Company of Connecticut and introduced in 1968.
Ruger Mini-14
The Ruger Mini-14 is a lightweight, gas-operated semi-automatic rifle made by Sturm, Ruger & Co., designed by L. James Sullivan and William B. Ruger and introduced in 1973.
Ruger P series
The Ruger P series is a line of semi-automatic pistols made by Sturm, Ruger & Company from 1987 to 2013, starting with the 9 mm P85.
Ruger SR-556
The Ruger SR-556 is a semiautomatic, AR-15-pattern rifle made by Sturm, Ruger & Company from 2009 to the mid-2010s, Ruger's first entry into the AR-style rifle market.
Ruger Standard
The Ruger Standard, also called the Ruger Mark I, is a .22 Long Rifle semi-automatic pistol introduced in 1949 as Sturm, Ruger & Co.'s first product.
Rui Wang (engineer)
Rui Wang (王睿) is a Chinese materials scientist and tenured associate professor at Westlake University known for defect passivation and crystallization control in perovskite solar cells, including a 2023 Nature paper reaching 25% efficiency.
Rui Zhang
Rui Zhang (Zhang Rui) is a Singapore-based wireless communications researcher and Provost's Chair Professor at the National University of Singapore, known for wireless power transfer.
Ruijin power station
Ruijin power station (华能瑞金发电厂) is a 2,700 MW coal-fired power station in Gan County, Ganzhou, Jiangxi, China, built in 2008 and expanded with two 1,000 MW ultra-supercritical units in 2021.
Ruins of Buddhist Temples and Images
Ruins of Buddhist temples and images at Odisha's Diamond Triangle: Lalitgiri, Ratnagiri, and Udayagiri, excavated monasteries, stupas, relic caskets, and Mahayana-Vajrayana sculpture from the 2nd century BCE to the 13th century CE.
Rule 21 (California)
Rule 21 is a California Public Utilities Commission tariff setting interconnection requirements for generation and storage connecting to the state's investor-owned utilities' grids, first adopted in 1982.
Rule induction
Rule induction is a machine learning method that learns a readable set of if-then rules from labeled examples, chosen for classification tasks where the model must be transparent, as in medical classification.
Rule of 40
The Rule of 40 is a SaaS financial heuristic stating that revenue growth rate plus profit margin should equal 40 percent or more, popularized by Brad Feld in 2015.
Rule of the road (railways)
The rule of the road on railways is the convention by which trains on double-track lines keep to the left or the right, often differing from road traffic.
Ruled paper
Ruled paper, also called lined paper, is paper printed with horizontal lines, and sometimes vertical margins, that guide handwriting; mechanized by pen-ruling machines in the 1840s.
RULER (artificial intelligence)
RULER is a synthetic long-context benchmark from NVIDIA, introduced in April 2024 to measure a language model's effective context length rather than its advertised window.