Technology glossary

Dilution of Precision(DOP)

Dilution of Precision (DOP) describes how satellite geometry amplifies or reduces GNSS measurement errors. Satellites spread widely across the sky generally produce better geometry and a lower DOP than satellites clustered in one direction.

Dilution Refrigerator

A cooling system that uses mixtures of helium isotopes to reach temperatures of a few millikelvin.

Direct Imaging of Exoplanets

The detection of light coming from an exoplanet as a spatially separate source from its host star. Because starlight is overwhelmingly brighter, the method uses high-contrast optics, coronagraphs, adaptive optics, or interferometry and is best suited to certain large, young, or widely separated planets.

Direct Liquid Cooling

A cooling method that brings liquid close to, or directly across, heat-producing components such as processors and accelerators. Liquid carries heat more effectively than air and can reduce fan and chiller requirements in dense computing systems.

Directed Evolution

An engineering method that repeatedly mutates and selects biological molecules to improve a desired function.

Disc-to-Digital

A system that uses a verified physical game disc to authorize downloading, streaming, or otherwise accessing a digital version while preserving rules tied to the original disc.

Discretionary Grant

Public funding awarded through an agency's judgment rather than paid automatically under a fixed eligibility formula. Applicants usually compete under stated criteria, and the agency selects projects that fit the program's purpose and available budget. The word discretionary describes the decision process, not permission to ignore laws or published rules.

Dissipative Entanglement

Quantum entanglement created or stabilized through carefully engineered interaction between a quantum system and its environment. Instead of treating dissipation only as harmful noise, researchers design it to drive the system toward a desired entangled state.

District Heat Recovery

The capture of otherwise wasted heat from facilities such as data centers and its transfer into a local network that heats buildings or water. Its usefulness depends on temperature, distance, seasonal demand and the energy required to move the heat.

DNA Metabarcoding

A method that identifies many species in a mixed environmental or biological sample by sequencing short diagnostic regions of DNA and comparing them with reference databases.

DNA Origami

A nanotechnology method that folds a long DNA strand into a planned shape using many shorter strands as molecular staples. The resulting structure can position molecules with nanometre precision and can be designed to move, bind targets or carry cargo.

DNA Strand Displacement

A programmable reaction in which one DNA strand binds to a matching exposed region and replaces another strand in a DNA complex. Designers use the sequence of bases to control which reaction happens and when, allowing DNA devices to behave like molecular switches or motors.

DNAzyme

A DNA molecule selected or engineered to catalyse a chemical reaction, rather than merely store genetic information. Many DNAzymes cut a specific RNA sequence when the required metal ions and molecular conditions are present.

Driver Mutation

A genetic change that gives a cell a growth advantage and contributes directly to cancer development.

Droplet Microfluidics

A technique that moves and manipulates tiny droplets through microscopic channels. Each droplet can serve as an isolated reaction vessel, allowing many experiments to run with very small quantities of material.

Drug-Likeness

A set of chemical and physical properties used to estimate whether a molecule could become a practical medicine.

Dual-Frequency GNSS

Dual-frequency GNSS receivers track satellite signals on two radio frequencies. Comparing the two helps correct ionospheric delay and can improve accuracy and robustness compared with single-frequency positioning.

Durability of Response(DoR)

The length of time a clinically meaningful improvement or tumor response persists after it begins. In oncology, duration of response is typically measured from the first documented response until disease progression or death under a predefined study protocol.

Dynamic Balance

The ability of a moving system to manage momentum and recover stability while its centre of mass may temporarily move outside the current support area. Running robots maintain it by sensing body motion and adjusting foot placement and joint forces in real time.

Dynamic Tissue Culture

A method for growing engineered tissue while applying controlled motion, pressure, flow or stretching. These physical cues can help cells organize and mature more like tissue inside a living body.

E911(E911)

Enhanced 911 (E911) is a U.S. emergency-calling capability that provides dispatchers with additional information, including the caller's location. Wireless E911 requirements helped accelerate deployment of location-capable mobile handsets and assisted-GPS technologies.

Early-Universe Black Hole

A black hole that formed during the universe's first hundreds of millions to roughly one billion years. Such objects, especially rapidly grown supermassive black holes powering distant quasars, help test theories of black-hole seeds, accretion, galaxy formation, and early cosmic evolution.

Earth System Model

A computer model that links the atmosphere, oceans, land, ice and biological or chemical cycles to simulate how the planet responds to forces such as greenhouse-gas emissions.

Ectodomain Shedding

A process in which an enzyme cuts the portion of a membrane protein that projects outside the cell, releasing that fragment into the surrounding fluid or bloodstream. The mechanism can rapidly change cell signaling without waiting for a new protein to be made.

Eddy Current

A circulating electrical current induced inside a conductor by a changing magnetic field. In motor and transformer cores, eddy currents waste energy as heat, so laminations or insulated particles are used to interrupt their paths.

Edge Computing

Processing data near the device or sensor that generates it instead of sending everything to a distant data center.

Effective Radiative Forcing(ERF)

A measure of how a change in greenhouse gases, clouds or other factors alters Earth’s energy balance after rapid atmospheric adjustments. Positive effective radiative forcing tends to warm the climate, while negative forcing tends to cool it.

El Niño-Southern Oscillation(ENSO)

A recurring tropical Pacific climate cycle that alternates among warmer El Niño, cooler La Niña and neutral conditions, reshaping weather worldwide.

Elastocaloric Effect

A reversible temperature change in certain materials when mechanical stress is applied or removed, allowing repeated loading cycles to pump heat.

Electric Propulsion

Spacecraft propulsion that uses electrical energy to accelerate propellant, commonly through electrostatic, electromagnetic, or electrothermal methods. It generally provides higher propellant efficiency but lower thrust than chemical rockets, making it suitable for long-duration missions and station keeping.