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from article Helmholtz resonator
Helmholtz resonator. Symbols are explained in text.
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from article Calculator
Electromechanical calculator manufactured in the 1960s. (Hewlett-Packard)
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from article Calculator
Modern programmable electronic calculator. (a) Front of calculator, featuring liquid-crystal display, qwerty-style keyboard, cursor key, and function keys. The display is composed of 128 rows of 240 pixels each, and here shows a three-dimensional…
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from article Lawson criterion
Typical plot of minimum value of nτ necessary for net release of energy versus ion kinetic temperature in a mixture containing equal amounts of deuterium and tritium. (After J. M. Hollander, ed., Annu. Rev. Energy, 1:213–255, 1976)
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from article Milky Way Galaxy
The Milky Way as seen from the Atacama Desert in Chile at an altitude of around 3,650 m (12,000 ft), with large cacti silhouetted in the foreground. (Credit: ESO/S. Guisard )
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from article Milky Way Galaxy
An artist’s impression of the Milky Way Galaxy as seen from above and with the approximate location of the Sun labeled. [Credit: NASA/JPL-Caltech/R. Hurt (SSC)]
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from article Milky Way Galaxy
Infrared image of the Milky Way as seen from the location of the Sun, made from the 2MASS infrared sky survey. The image shows both the bulge and the disk of the Milky Way. Absorption by dust is minimized in the infrared, which accounts for the…
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from article Milky Way Galaxy
NGC 4603, a galaxy with a gross morphology similar to the Milky Way, seen obliquely. The spiral arms and the bulge are visible in the center. The bulge appears to be elongated because the galaxy also contains a bar, an extended feature containing…
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from article Milky Way Galaxy
A combination of X-ray and radio emission data from the core of the Milky Way, revealing the three-armed “minispiral” structure, with Sagittarius A* labeled, as well as other features including a jet blasted out by the supermassive black hole.…
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from article Vibrotaction
Block diagram of apparatus for determining vibrotactile perception thresholds at the fingertip.
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from article Vibrotaction
Tactogram showing the approximate maximum threshold recorded at the fingertips of healthy persons (horizontal line), and examples of two types of threshold elevation (reduction in acuity) at selected frequencies (circles and squares).
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from article Virgo Cluster
Distribution of members of the Virgo Cluster on the sky, as determined in the du Pont Telescope survey. (After O.-G. Richter and B. Binggeli, eds., The Virgo Cluster, European Southern Observatory, 1985)
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from article Virgo Cluster
Central area of the Virgo Cluster, showing some of its brightest galaxy members. (Canada-France-Hawaii Telescope image courtesy of C. Cuillandre)
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from article Virgo Cluster
X-ray image of the entire Virgo Cluster. The main blob is centered on the giant active galaxy M87 (see Fig. 4). (Image from Roentgen Satellite (ROSAT) courtesy of NASA)
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from article Virgo Cluster
Giant elliptical galaxy M87. It is one of the brightest galaxies in the Virgo Cluster and is notable for its extremely massive central black hole. (Canada-France-Hawaii Telescope image courtesy of C. Cuillandre)
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from article Virgo Cluster
Sombrero Galaxy in an image obtained with the Spitzer Space Telescope. The spheroidal galaxy of stars hosts a thin, spiral-shaped ring of dust, visible in the infrared because of the light emission from the warm dust grains. (NASA/Spitzer Science…
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from article Communications satellite
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 Pluto
An enhanced-color global view of Pluto taken by the New Horizons spacecraft on July 14, 2015, showing Pluto's diversity in surface texture and composition. The image (which actually is a mosaic of four images) resolves details on scales as small as…
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from article Pluto
Pluto and its five known moons, imaged by the Hubble Space Telescope on July 7, 2012. (Credit: NASA/ESA/Mark R. Showalter, SETI Institute)
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from article Pluto
A perspective view of the orbit of Pluto showing the inclination i and eccentricity of the orbit. The orbits of Jupiter, Saturn, Uranus, and Neptune are also shown. Terms: A, aphelion; P, perihelion; NN′, line of nodes. (Credit: Based on an original…
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from article Pluto
Two views of Pluto's vast nitrogen ice plain known as Sputnik Planitia. (Left) An enhanced-color close-up section of the glacial plains in the middle of Sputnik Planitia. (Right) A "scattering map" of the same region, created by combining two images…
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from article Pluto
Charon, pictured by New Horizons. (Credit: NASA/JHUAPL/SwRI)
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from article Herbig-Haro objects
Jet and bow-shock emission from Herbig-Haro 34. Two opposite jets run into the surrounding interstellar medium, where they terminate in Herbig-Haro objects with a characteristic bow-shock structure. The jets are composed of “bullets” of dense gas…
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from article Herbig-Haro objects
Spitzer Space Telescope infrared image and an optical Digital Sky Survey image of Herbig-Haro objects 46 and 47. The inset at the bottom left shows the optical image of the cloud in which the protostar is born and the associated Herbig-Haro objects…
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from article Herbig-Haro objects
Disk and jets associated with Herbig-Haro 30, showing changes between images taken in (a) 1995, (b) 1998 and (c) 2000 with the Wide Field and Planetary Camera 2 aboard the Hubble Space Telescope. A slightly flared disk of dust and gas appears…
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from article Medical waste
The uniform international biohazard symbol.
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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 Huntington's disease
Huntington's disease is a hereditary disorder that affects approximately five to ten of every 100,000 persons. The average age at onset is between 35 and 40 years. Invariably fatal, the disease progresses gradually over time. (Copyright ©…
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from article Cheese
Cheese being placed in brining tank (salt bath). (Credit: Westend61/Getty Images)
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from article Cheese
Cheese ripening. (Credit: Tom Paiva Photography/Blend Images)
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from article Cheese
Swiss cheese. (Credit: Tom Paiva Photography/Blend Images)
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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
Flow chart of an acid-base disorders algorithm. (Copyright © McGraw-Hill Education)
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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 Negative refraction
Refraction: Diagrams of (a) positive refraction and (b) negative refraction; and calculated images of a metal rod (c) in a glass filled with regular water (n = 1.3), and (d) in a glass filled with “ negative-index water ” (n = −1.3). In parts a and…
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from article Negative refraction
Schematics of (a) superlens, (b) hyperlens, and (c) imaging system using a hyperlens. In parts a and b, solid lines correspond to the propagating field components, broken lines correspond to the evanescent field components.
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from article Negative refraction
Cloaking. (a) The transformation of a cylindrical region r < b into a concentric cylindrical shell a < r < b and an enlarged section of a nonmagnetic optical cloak built with metal wires embedded in a dielectric host. (b) Numerical simulations of an…
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from article Belladonna
Close-up view of the belladonna plant (Atropa belladonna), showing the leaves and berries, which are toxic. (Credit: Leo Michels)
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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 Pharmacy
Pharmacy is the science dealing with the preparation and dispensing of medicinal or therapeutic drugs. (Credit: Sanchai Rat/Shutterstock)
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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 Sound absorption
Absorption of sound in air at 20°C (68°F) and various values of relative humidity. (From L. E. Kinsler et al., Fundamentals of Acoustics, 3d ed., Wiley, 1982; used by permission of John Wiley & Sons, Inc.)
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from article Sound absorption
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from article Sound absorption
Depiction of direct and reflected sound in a room with varying wall properties.
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from article Sound absorption
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from article Hepatitis C virus
Chronic hepatitis C with portal inflammation and interface hepatitis (erosion of the limiting plate of periportal hepatocytes by infiltrating mononuclear cells). (Copyright © McGraw Hill)
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from article Hepatitis C virus
Natural history of chronic hepatitis C. It is presumed that liver fibrosis progresses in a linear course from the time of acquisition of the infection to the development of cirrhosis. Stages of fibrosis are from the METAVIR (meta-analysis of…
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from article Hepatitis C virus
The genomic structure of hepatitis C virus (HCV) and potential targets for therapy. Through analysis of the genomic structure of HCV, additional therapies (for example, serine protease inhibitors, helicase inhibitors, and RNA polymerase inhibitors)…
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from article Lignin-degrading fungi
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from article Lignin-degrading fungi
Close-up view of Pleurotus spp. fruiting bodies growing naturally on a dead tree log. The common name of oyster mushroom comes from the shell-like appearance of the fruiting body. Note the characteristic eccentric caps.
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from article Radiation
Crepuscular rays, which are shafts of air illuminated by electromagnetic radiation (light) radiating from the Sun. [Credit: Danny Chapman / Flickr/ Attribution-ShareAlike 2.0 Generic ( CC BY-SA 2.0 )]
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from article Radiation
Illustration of gravitational radiation generated by the impending merger of two neutron stars. (Credit: R. Hurt/Caltech-JPL)
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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 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 Centroids (mathematics)
Notation of integral equations for centroids. (a) Centroid of line. (b) Centroid of area.
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from article Centroids (mathematics)
Determination of centroids by summation. (a) Centroid of line. (b) Centroid of area.
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from article Centroids (mathematics)
Plane areas symmetric about a line.
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from article Centroids (mathematics)
Plane area symmetric about a point.
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from article Centroids (mathematics)
Use of the centroid of a line to find area of a face of revolution, according to Pappus' theorem.
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from article Earth
The famous "Blue Marble" picture of Earth taken by astronauts during the Apollo 17 mission on December 7, 1972, while en route to the Moon. (Credit: NASA)
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from article Earth
Principal layers of Earth. (USGS)
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from article Earth
Global histogram (distribution of elevations) and hypsographic curve (cumulative elevations) of Earth's surface. (NOAA)
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from article Earth
Seafloor spreading. (USGS)
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from article Earth
Plate collisions: (a) continent-ocean plate collision; (b) continent-continent plate collision; (c) ocean-ocean plate collision. (USGS)
