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Artist impression of TDRS-L, the 11th member of NASA's Tracking and Data Relay Satellite System, orbiting Earth at 36,000 km (22,300 mi). TDRS-L sends signals, information, and commands from ground controllers to the International Space Station and…

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from article Communications satellite

Communications to and from a satellite.

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from article Communications satellite

Typical communications satellite. TWTA = traveling-wave–tube amplifier. (Credit: Space Systems/Loral)

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from article Communications satellite

Orbit periods of circular orbits.

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from article Polymer composite

Relation between stiffness and filler type and orientation in polymeric materials. L/D = length/diameter of fiber.

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from article Polymer composite

Load transfer from matrix to fiber in a composite. LC = critical length. σma = matrix stress.

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from article Polymer composite

Tensile modulus for various fibers.

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from article Polymer composite

Unidirectional continuous fiber–reinforced laminated structure. L = longitudinal direction. T = transverse direction.

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from article Polymer composite

Measured and predicted elastic modulus in a unidirectional fiber–reinforced laminate as a function of angle between the loading and fiber direction.

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from article Toggle

Toggle mechanism. (a) Simple structure. (b) Traditional configuration. (c) Typical application.

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from article Branched polymer

Examples of branched polymers. (a) Branched polymer (if arms are of composition similar to backbone) or graft polymer (if compositions are different). (b) Star polymer. (c) Comb polymer. (d) Dendritic polymer.

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from article Branched polymer

Reaction for preparation of a star polymer with styrene-butadiene block copolymer arms.

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from article Branched polymer

Steps in the synthesis of a starburst polymer. s = surface. o = interior. fr = reactive group. fp = protected group.

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from article Tangent

Line L tangent to curve C at P.

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from article Heterocyclic polymer

Structural units in linear polymers. (a) Simple linear polymer. (b) Stepladder polymer. (c) Ladder polymer.

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from article Heterocyclic polymer

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from article Medical waste

The uniform international biohazard symbol.

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from article Patellogastropoda

Whitecap limpet (Acmaea mitra). (Photo by Douglas Eernisse)

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from article Patellogastropoda

Ribbed Mediterranean limpet (Patella ferruginea). (Photo by Georgina Rivera Ingraham)

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from article Patellogastropoda

Radula of the patellogastropod Notoacmea scapha.

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from article Intermolecular force

Schematic diagram of intermolecular interaction. (a) There is negligible interaction between atoms that are 1 nm apart. (b) For atoms separated by about 0.8 nm or less, attractive dispersion forces result from correlated fluctuations of the electron…

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from article Ion beam mixing

Ion beam mixing of film and substrate. (a) Before ion bombardment. (b) Partial intermixing. (c) Complete intermixing.

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from article Ion beam mixing

Ion beam mixing of alternating films.

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from article Algorithm

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from article Algorithm

An array of n elements.

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from article Algorithm

Inserting and deleting an element from a stack.

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from article Algorithm

Inserting and removing an element from a queue.

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from article Algorithm

An example of a tree.

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from article Algorithm

A graph with four vertices and five edges.

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from article Masking of sound

Three psychophysical tuning curves, showing the tonal masking effects for tonal signals of 300, 1000, or 3000 Hz. (After F. L. Wightman et al. Factors influencing frequency selectivity in normal and hearing-impaired listeners, in E. F. Evans and J.…

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from article Masking of sound

Width of the critical band in hertz as a function of signal frequency.

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from article Masking of sound

Relative amount of masking obtained in forward, simultaneous, and backward masking. (After W. A. Yost, Fundamentals of Hearing: An Introduction, 4th ed., Academic Press, New York, 2000)

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from article Masking of sound

Masking of a 1000-Hz pure-tone signal in forward masking when the masker is a two-tone complex consisting of a 1000-Hz masker and a second tone. (a) Threshold of signal for the two-tone masker relative to that obtained when only the 1000-Hz tone…

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from article Hazardous waste

Inspector determining the compliance status of a facility that generates and handles hazardous waste. (Credit: West Virginia Department of Environmental Protection)

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from article Azeotropic distillation

Schematic representation of the residue curve map for nonazeotropic ternary mixtures.

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from article Azeotropic distillation

Schematic representation of the residue curve maps for ternary mixtures with one minimum-boiling binary azeotrope. (a) Azeotrope between the lowest- and highest-boiling components. (b) Azeotrope between the intermediate- and highest-boiling…

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from article Azeotropic distillation

Classical extractive distillation of ethanol and water using ethylene glycol as entrainer. (a) Residue curve map. Temperatures shown are the normal boiling points of the pure components and the azeotrope. Binary azeotropic composition is not drawn…

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from article Azeotropic distillation

Typical sequence of columns for heterogeneous azeotropic distillation, for example, ethanol + water + benzene (entrainer).

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from article Capability maturity modeling

Capability Maturity Models: the continuous representation.

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from article Capability maturity modeling

Organizational maturity levels.

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from article Capability maturity modeling

Capability Maturity Models: the staged representation.

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from article Capability maturity modeling

CMMI model evolution.

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from article Intelligent machine

Driverless cars use sensor-based data to make decisions. (Credit: monicaodo/Shutterstock)

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from article Intelligent machine

Flow of information and data in a typical intelligent machine.

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from article Television

Interlace scanning pattern (raster) of the television image.

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from article Television

NTSC color television waveform. (a) Principal components. (b) Detail of picture elements. (Electronic Industries Association)

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from article Television

ITU-R Digital terrestrial television broadcasting model of the International Telecommunications Union, Radiocommunication Sector (ITU-R). (From Advanced Television Systems Committee, ATSC Digital Television Standard, Doc. A/53B, 2001)

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from article Television

High-level view of the DTV encoding system, illustrating the relationship and derivation of various clock frequencies within the encoder and the use of forward error correction (FEC). A/D = analog-to-digital. VSB = vestigial sideband. (From Advanced…

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from article Television

Sample organization of functionality in a transmitter-receiver pair for a single DTV program. PSIP = Progam and System Information Protocol, PES = packetized elementary stream, PSI = program-specific information. (From Advanced Television Systems…

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from article Television

Common image aspect ratio formats. (After K. B. Benson and D. G. Fink: HDTV: Advanced Television for the 1990s, McGraw-Hill, New York, 1990)

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from article Nitrogen oxides

Nitrogen-oxide structures. Blue = nitrogen. Red = oxygen.

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from article Energy storage

Specific range of vehicles using energy stored in various forms. 1 mi/ft3 = 57 km/m3.

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from article Energy storage

Concept of an underground pumped hydroelectric storage system.

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from article Energy storage

Schematic diagram of compressed-air storage plant at Huntorf, Germany.

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from article Energy storage

Schematic diagram of zinc-chloride battery, showing two main compartments in the design, the battery stack and the chlorine hydrate store. (a) Charge cycle. (b) Discharge cycle. (Gulf and Western Co.)

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from article Energy storage

Impact of solar-electric generation on utility load curve during a typical 24-h period.

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from article Data science

Data science is multidisciplinary. (Credit: Brendan Tierney, Technological University Dublin, Oralytics Blog)

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from article Data science

Data science life cycle. [Credit: Kenneth Jensen (CC BY-SA 3.0)]

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from article Nerve agent

Chemical structure of the nerve agent tabun (GA), C5H11N2O2P.

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from article Nerve agent

An example of hazardous materials workers wearing personal protective equipment (PPE), as might be worn to protect against nerve agent exposure. (Credit: CDC Public Health Image Library)

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from article Nerve agent

A practice exercise at the Centers for Disease Control and Prevention showing responders using a decontamination station, as might be used after a nerve agent incident. (Credit: CDC Public Health Image Library/Kathy Nellis Chastney)

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from article Nerve agent

Example of auto-injector syringes for atropine and pralidoxime, two antidotes for nerve agent exposure, from a Mark 1 Nerve Agent Antidote Kit (NAAK). (Credit: ATSDR/CDC)

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from article Machining

Broach cutting a small chip from a workpiece.

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from article Machining

Critical items on a drill point and their geometry. (a) End view. (b) Side view. (c) Side view, with drill rotated 90° about its axis from the position shown in b.

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from article Machining

Formation of turning chips as a single-point tool contacts the exterior of the spinning workpiece.

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from article Machining

Action of a grinding wheel, showing how individual grains of the wheel produce chips from a workpiece.

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from article Machining

Configuration of a centerless grinding wheel.

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from article Machining

Creep-feed grinding process.

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from article Machining

Electric-discharge, or electric-spark, machining process. (Elox Corporation of Michigan)

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from article Machining

Gear hobbing operation; rotation of the hob and gear blank is synchronized and continuous. (After J. G. Bralla, ed., Handbook of Product Design for Manufacturing, McGraw-Hill, 1986)

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from article Ventilation

Roof exhausts for natural ventilation. (a) Cross section of round ventilator and (b) of rotating-head ventilator. (c) Continuous roof ventilator.

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from article Ventilation

Building cross section illustrating motivating convection head (height) for natural ventilation.

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from article Ventilation

Factory-assembled ventilating unit.

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from article Ventilation

Mechanically powered roof air supply unit. For summer ventilation, the portion shown in solid lines is used. Heater and dampers are for winter use. Diffuser outlet improves air distribution into ventilated space.

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from article Hydraulic actuator

Function of a hydraulic double-acting cylinder.

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from article Hydraulic actuator

Types of hydraulic cylinder (linear) actuators. (a) Single-acting, external return. (b) Single-acting, spring return. (c) Telescopic. (d) Double-acting double-ended rod. (e) Tandem cylinders.

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from article Hydraulic actuator

Piston-rack type rotary actuator.

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from article Hydraulic actuator

Single-vane rotary actuator.

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from article Hydraulic actuator

Gear motor rotary actuator.

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from article Hydraulic actuator

Vane motor rotary actuator.

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from article Nuclear power

Aerial view of a nuclear power plant with one cooling tower (at right). The containment structure housing the nuclear reactor and its fissile uranium fuel is the gray, domed structure rising above the rest of the support buildings at center.…

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from article Nuclear power

Advanced boiling-water reactor (ABWR), the first advanced light-water reactor to be deployed commercially. (Credit: General Electric)

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from article Nuclear power

Aerial image of the stricken Fukushima Daiichi nuclear power plant, showing damaged reactor buildings. (Credit: Department of Energy Aerial Measuring System)

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from article Sauropterygia

Ceresiosaurus calcagnii, ventral view.

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from article Hyperbola

Hyperbola as a conic section.

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from article Hyperbola

Hyperbola as a locus of points.

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from article Alicyclic hydrocarbon

Internal bond angles (α) for (a–c) planar rings and (d) a tetrahedral carbon atom.

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from article Alicyclic hydrocarbon

Nonplanar (a) chair and (b) boat structures of cyclohexane.

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from article Alcohol

Ethanol production plant. (Credit: Julie Kendall/Getty Images)

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from article Alcohol

E85 is a gasoline-ethanol blend containing 51 to 83% ethanol. It is used in flexible-fuel vehicles, which can operate on gasoline or blends of gasoline and ethanol. About 20 million flexible-fuel vehicles are operating in the United States. (Credit:…

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from article Fluids

Probability of finding molecular centers at various separations in gases, liquids, and solids.

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from article Fluids

Conditions of pure-component phase behavior.

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from article Fluids

Behavior of pure-component pressures with density at various temperatures.

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from article Fluids

Behavior of pure-component compressibility factors with pressure at various temperatures.

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from article Gate circuit

Switch circuit architecture. (a) CMOS transmission gate, with an NMOS and a PMOS transistor in parallel, clocked at opposite clock signals (C and ). (b) Switch circuit for two-input logic AND function, with two normally-OFF switches in series and…

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from article Gate circuit