Technology and the built world

Composite phase-change materials

Composite phase-change materials (CPCMs) are thermal storage materials combining a phase-change material, such as paraffin wax, with conductive supports to overcome low conductivity, leakage, and poor stability.

Composite recycling

Composite recycling is the recovery of fibers, matrix, or energy from fiber-reinforced polymer composites such as fiberglass and carbon fiber, chiefly by mechanical, thermal, and chemical methods.

Composite rigid body algorithm

The composite rigid body algorithm (CRBA) is a recursive robot dynamics method that computes the joint-space inertia matrix, named by Roy Featherstone after Walker and Orin's 1982 method.

Composite video

Composite video, best known as CVBS, is an analog video format that combines luminance, chrominance, and sync into one signal, the yellow-cable connection of consumer video equipment.

Composition B

Composition B, or Comp B, is a castable military explosive of RDX and TNT, a standard burst charge for bombs and shells since World War II.

Composition engineering of perovskite solar cells

Composition engineering is the deliberate tuning of the A, B, and X sites of a perovskite absorber's ABX3 lattice to control a solar cell's bandgap, efficiency, and stability.

Composition over inheritance

Composition over inheritance, also called the composite reuse principle, is an object-oriented design principle favoring object composition over class inheritance, stated in the 1994 book Design Patterns.

Compositional engineering of perovskite materials

Compositional engineering of perovskite materials is the deliberate adjustment of the composition of metal halide perovskites, ABX3 semiconductors used mainly in solar cells, to tune the bandgap and stability.

Composting toilet

A composting toilet is a waterless or micro-flush sanitation system that decomposes human waste aerobically into humus, used where sewers, water, or suitable soil are unavailable.

Compound casting

Compound casting is a casting process that joins two different metals by casting molten metal around a solid insert, producing one bimetallic part with a metallurgical bond.

Comprehensive Everglades Restoration Plan

The Comprehensive Everglades Restoration Plan, known as CERP, is a federal-state program, authorized in 2000, to restore water flow in the Everglades while providing flood protection.

Comprehensive Research Facility for Fusion Technology

The Comprehensive Research Facility for Fusion Technology (CRAFT) is a Chinese national facility in Hefei testing superconducting magnets, divertor components, and other fusion reactor technologies.

Compressed air

Compressed air, also called pressurized air, is atmospheric air mechanically compressed to raise its pressure, used to power industrial tools and actuators and to store electricity in grid-scale plants.

Compressed air tunneling

Compressed air tunneling is a construction method that pressurizes the tunnel so air pressure balances groundwater pressure, first used in 1879 and now confined mainly to brief TBM face interventions.

Compressed biogas

Compressed biogas (CBG), also called compressed biomethane or bio-CNG, is purified biogas with most carbon dioxide removed, compressed for use as a vehicle fuel or grid gas.

Compressed hydrogen tube trailer

A compressed hydrogen tube trailer is a semi-trailer fitted with high-pressure cylinders, typically filled to about 200 bar, that delivers gaseous hydrogen to refueling stations by road.

Compressed natural gas

Compressed natural gas (CNG) is natural gas, mostly methane, pressurized to less than 1% of its volume so it can be stored onboard vehicles and burned in engines.

Compressed-air energy storage

Compressed-air energy storage (CAES) is a grid-scale technology that stores surplus electricity as compressed air, usually in underground caverns, and expands it through a turboexpander to regenerate electricity.

Compressed-air working in shield tunnels

Compressed-air working in shield tunnels is the practice of pressurizing a tunnel or TBM head chamber with air to hold back groundwater and stabilize the face during excavation.

Oct 21, 2026

Compression Algorithms

Compression Algorithms: methods that reduce and restore file size, lossless or lossy. Spans Shannon entropy limits, Huffman coding, Lempel-Ziv LZ77/LZ78, DEFLATE, zstd and Brotli, and neural compression.

Compression Attached Memory Module

The Compression Attached Memory Module (CAMM2), also called LPCAMM2 in its low-power variant, is a JEDEC-standardized memory module that mounts flat against a compression connector on the motherboard.

Compression molding

Compression molding is a manufacturing process that presses softened polymer, rubber, or composite material between heated mold halves, curing it under pressure, and is the largest primary process for automotive composites.

Compression ratio

Compression ratio is the ratio of maximum to minimum cylinder volume in a piston engine, ranging from 9:1 to 12:1 in gasoline engines and 16:1 to 21:1 in diesels.

Compression release engine brake

A compression release engine brake, or Jake Brake, slows a vehicle by opening a diesel engine's exhaust valves to release compressed air, patented by Clessie Cummins in 1957.

Compression set

Compression set is the permanent deformation that remains in an elastomer, such as an O-ring or gasket, after prolonged compression, measured by standards like ASTM D395.

Compression splice

A compression splice is a tubular metal fitting crimped onto the two ends of an overhead power conductor, forming a full-tension joint that carries both mechanical load and electrical current.

Compressive imaging

Compressive imaging is an imaging method that reconstructs images or videos from fewer measurements than the number of pixels, exploiting sparsity, applied in MRI, hyperspectral video, and single-pixel cameras.

Compressive Sampling Matching Pursuit

Compressive Sampling Matching Pursuit (CoSaMP) is an iterative greedy algorithm that reconstructs sparse signals from few linear measurements, introduced by Deanna Needell and Joel Tropp in 2008.

Compressive Sensing Radar

Compressive sensing radar is a class of radar systems and imaging methods that reconstruct sparse target scenes from under-sampled measurements, replacing matched filtering and reducing required samples, pulses, and antennas.