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Concentrator photovoltaics
Concentrator photovoltaics (CPV) is a solar technology that uses lenses or mirrors to concentrate sunlight 200 to 1000 times onto small, high-efficiency multijunction cells, cutting semiconductor costs.
Concentric castle
Concentric castle: medieval fortress with two or more rings of curtain walls, inner wall taller than outer; exemplified by Edward I's Welsh castles (Beaumaris, Harlech, Conwy, Caernarfon) and Dover.
Concentric tube robots
Concentric tube robots, also known as active cannulas, are continuum robots of nested precurved elastic tubes whose relative rotation and translation set the tip's shape and position.
Concentrically braced frame
A concentrically braced frame (CBF) is a steel lateral-force-resisting system whose diagonal braces carry load through axial forces, widely used for seismic and wind design.
Concept activation vectors
A concept activation vector (CAV) is a direction in a trained neural network's internal activation space that corresponds to a human-defined concept, introduced by Google researchers in 2018.
Concept bottleneck models
A concept bottleneck model (CBM) is an interpretable machine learning architecture that predicts a target label only through an intermediate layer of human-understandable concepts, introduced in 2020.
Concept car
A concept car is a vehicle built by an automaker to display a new design or technology rather than to be sold, beginning with the 1938 Buick Y-Job.
ConceptNet
ConceptNet is a freely available, multilingual commonsense knowledge base connecting words and phrases with everyday relationships, created by Hugo Liu and Push Singh at the MIT Media Lab in 2004 and maintained by Luminoso Technologies.
Concepts NREC
Concepts NREC is a turbomachinery engineering and software company in White River Junction, Vermont, formed in 2000 when Concepts ETI acquired the Northern Research and Engineering Corporation's assets.
Conceptual Captions
Conceptual Captions (CC3M) is a Google dataset of about 3.3 million image-caption pairs harvested from the alt text of web images, introduced in 2018 and widely used for vision-and-language pre-training.
Conceptual graph
A conceptual graph (CG) is a graph representation for logic, introduced by John F. Sowa in 1976 to express the meaning of natural-language sentences for computers.
Conceptual model
A conceptual model, also called an abstract model, is a technology-independent representation of a domain's data, made in the initial phase of database design or software development.
Concertina wire
Concertina wire, also known as Dannert wire, is coiled barbed or razor wire that stretches into a military wire obstacle, widely used since the First World War.
Concession (contract)
A concession, or concession agreement, is a long-term contract granting a private company the right to operate public infrastructure, recovering costs mainly from user payments.
Concetta La Marca
Concetta La Marca is a chemical engineer and Senior Principal Consultant at The Chemours Company, elected to the National Academy of Engineering in 2025 for her industrial reaction engineering work.
Concolic testing
Concolic testing, also known as dynamic symbolic execution, is a software testing method combining concrete program execution with symbolic analysis to generate inputs that steer programs down new execution paths.
Concorde
Concorde was an Anglo-French supersonic airliner, built by Aérospatiale and the British Aircraft Corporation, that cruised at twice the speed of sound and flew passengers from 1976 to 2003.
Concorde operational history
Concorde operational history covers the Anglo-French supersonic airliner Concorde, operating almost exclusively from 1976 to 2003, cutting transatlantic travel times and briefly serving U.S. routes for Braniff International.
Concrete
Concrete is a composite construction material made from cement, water, and sand or crushed stone, hardening through a chemical reaction; about 26 gigatonnes are produced yearly.
Concrete masonry unit
The concrete masonry unit (CMU), commonly called concrete block, is a hollow or solid block used in walls, made from a dry concrete mix and vibration-compacted.
Concrete mix design
Concrete mix design is the procedure for proportioning cement, aggregates, water, and admixtures so concrete meets specified strength, workability, and durability requirements, yielding masses per cubic meter.
Concrete mixer
A concrete mixer, also called a cement mixer, is a machine that blends cement, aggregates, sand, and water into uniform concrete, ranging from portable site drums to truck-mounted units.
Concrete pole
A concrete pole is a utility pole made of reinforced or prestressed concrete, supporting power and telecom lines; typically spun, it resists fire, rot, and termites, and lasts roughly 60 years.
Concrete ship
A concrete ship is a vessel whose hull is built of concrete, usually steel-reinforced, built in large numbers during both World Wars amid steel shortages.
Concrete slab
A concrete slab, or floor-slab, is a flat layer of plain or reinforced concrete supported on beams, walls, or the ground, serving as a floor or roof.
Concrete sleeper
A concrete sleeper, called a concrete railroad tie in North America, is a precast concrete beam laid across ballasted track to support rails and maintain track geometry.
Concrete slump test
The concrete slump test, also called the Abrams test, measures the consistency of fresh concrete by how much a molded sample settles after the cone mold is removed.
Concrete thermal energy storage
Concrete thermal energy storage (CTES) is a sensible heat storage technology in which concrete blocks cast around steel pipes store heat at up to 400 °C.
Concrete-face rock-fill dam
A concrete-face rock-fill dam (CFRD) is an embankment dam of compacted rockfill sealed by a reinforced-concrete upstream face carrying the water load; it became common in the 1990s.
Concrete-face rockfill dam
A concrete-face rockfill dam (CFRD) is an embankment dam built almost entirely of rockfill, with a reinforced concrete upstream face as the watertight barrier, preferred for dams over 100 m.