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from article Red Sea

Division of the Red Sea into regions representing different stages in the formation of an ocean basin. (After F. Martinez and J. R. Cochran, Structure and tectonics of the northern Red Sea: Catching a continental margin between rifting and drifting,…

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from article Basalt

Devils Postpile, Mammoth Lakes, California, United States, which formed about 82,000 years ago, is a great example of columnar basalt. (Credit: U.S. National Park Service)

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from article Basalt

Thin section of upper crust of lava about 3 cm from top; black is microcrystalline groundmass. 0.5 mm = 0.02 in.

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from article Basalt

Thin section of interior of lava shown in Fig. 1, but 7.9 m (26 ft) below the top of the flow. Clear plagioclase crystals are ophitically enclosed in large pyroxene grains up to 1 mm in diameter. Crystals of black magnetite are minor. A few…

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from article Basalt

Growth of crystals as a function of temperature in basalt in Hawaiian lava. °F = (°C × 1.8) + 32.

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from article Basalt

Diagrams illustrating the compositions of basalts in terms of normative mineral formulas. Customarily, CaAl2Si2O8 (anorthite) is grouped together with NaAlSi3O8 (albite), and Fe2SiO4, FeSiO3, and CaFeSi2O6 are grouped with the corresponding Mg…

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from article Evolutionary computation

Typical flowchart for an evolutionary algorithm.

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from article Evolutionary computation

Traveling salesperson problem comprising 1000 cities. (a) Best-evolved solution after examination of 4 × 107 possible solutions. (b) Rate of evolutionary optimization.

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from article Evolutionary computation

Arrangement for distributing an evolutionary algorithm across multiple processors. Each processor holds its own population that undergoes random variation and selection. Occasionally, solutions will migrate from one population to another and begin…

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from article Ordovician

Ordovician, the second period of the Paleozoic Era.

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from article Ordovician

Early Ordovician (Arenig) paleogeography, major rock suites and potential ocean surface currents; based on remanent magnetism data supplemented by plots of the positions of shelf sea carbonates and reefs.

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from article Decision theory

Decision tree for the problem given in the text. Numbers at nodes represent time past alarm (7:00 A.M.), and numbers at branches refer to the decision mode or state of nature.

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from article Decision theory

From of a decision matrix. Oij = outcome corresponding to the interaction of a strategy (Si) and a state of nature (Nj).

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from article Decision theory

Decision tree structure to determine the subjective utility of lottery outcomes.

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from article Decision theory

Hypothetical subjective utility curves.

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from article Granite

Granite. (Credit: paylessimages/Getty Images)

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from article Granite

Classification of granitic rocks by the IUGS scheme. All proportions are by volume percentages.

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from article South America

Map of South America.

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from article South America

Andes Mountains, Chile. The Andes, which parallel the Pacific coast, constitute one of the Earth's most majestic features. Only the Himalayas exceed them in elevation and mass. (United Press International)

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from article South America

Representative view of the hilly uplands and low mountain country of the Guiana Highlands. One of five waterfalls on the Canaima River, Gran Sabana in southern Venezuela. (Venezuelan Information Service)

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from article South America

Uplifted beaches on desert coast, east side of San Juan Bay, Departmento de Ica, Peru. The sea cliff is about 100 ft (30 m) high. Each horizontal line represents a former beach. (Photograph by F. Atchley)

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from article South America

Port of Matarani on the desert coast of southern Peru. This oblique aerial view looks coastwise southward over one of the world's driest and most barren coastal zones. (Servicio Aerofotográfico Nacional)

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from article Zosterophyllopsida

Examples of Devonian Zosterophyllopsida. (a) Reconstruction of the Early Devonian Zosterophyllum rhenanum, here depicted as an aquatic plant (after R. Kräusel and H. Weyland, Neue Pflanzenfunde im rheinischen Unterdevon, Palaeontographica B,…

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from article Bytownite

Bytownite, from Crystal Bay, Minnesota. (Specimen from Department of Geology, Bryn Mawr College)

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from article Ophiuroidea

Representative ophiuroids, which have a quite distinctive shape. (a) Ophiopeza cylindrica (alternatively, Pectinura cylindrica). (b) Asteroporpa australiensis (alternatively, Astroporpa wilsoni). (c) Gorgonocephalus chilensis.

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from article Ophiuroidea

External features of the ophiuroid Amphiura. (a) Aboral view. (b) Adoral view.

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from article Virtual reality

The Duke immersive Virtual Environment. (Credit: Courtesy of the Duke University Pratt School of Engineering)

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from article Metamorphic rock

Gneiss. Most gneisses are formed by recrystallization of preexisting rock during metamorphism. Shear stress present during such metamorphism causes the formation of banding. (Credit: Tyler Boyes/Getty Images)

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from article Metamorphic rock

Fabrics of metamorphic rocks under microscope. (a) Mortar fabric; (b) flaser or mylonitic fabric; (c) granoblastic fabric. (d) Lepidoblastic fabric; (e) nematoblastic fabric; (f) porphyroblast with reaction rim.

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from article Metamorphic rock

Diagram showing the general relationship between deformation folding and slaty cleavage caused by pressure PP or the couple ScSc. Heavy black lines denote the original bedding deformed into folds. Thin lines indicate slaty cleavage which may grow…

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from article Metamorphic rock

Mineral facies groups of regional metamorphic rocks showing the temperature and pressure of metamorphism. °F = (°C × 1.8) + 32.1 km = 0.6 mi.

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from article Geographic information system

Comparison of (a) raster and (b) vector data models at the boundary of a residential housing subdivision. Raster data files consist of rows of uniform cells coded according to data values. Raster files are easily manipulated, but are less detailed…

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from article Geographic information system

Overlay analysis using raster data files.

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from article Chaos

Graphic depicting extreme rainfall totals in the state of South Carolina in early October, 2015, which according to National Weather Service statistics represented a 1,000-year rainfall event, meaning such an event is expected to occur about once…

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from article Chaos

Transition from order to chaos (turbulence) in a rising column of cigarette smoke. The initial smooth streamline flow represents order, while the erratic flow represents chaos.

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from article Chaos

Three-dimensional visualization of the Lorenz butterfly as traced out by the trajectory of the original simulation reported by Lorenz in 1963 (σ = 10, b = 8/3, r = 28) with initial conditions (X, Y, Z) = (0, 1, 0). The integration was performed with…

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from article Chaos

Separation of solutions on the Lorenz attractor. The two trajectories starting from the nearby initial points indicated by the balls in the right lobe of the attractor stay together for several circuits around both lobes and then separate as they…

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from article Chaos

Examples of fractal (self-similar) sets. (a) The Mandelbrot set in the complex plane, with origin indicated by the cross. A single point in the complex plane (in this case C = 0.314 − 0.537 i, where 1 = 1 ) generates (b) an associated Julia set.

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from article Chaos

Representations of pendulum motion corresponding to a periodic variation in angular position θ whose amplitude is just less than π radians (180°). (a) Phase-space representation (plot of momentum p versus θ). (b) Time plots of θ and of p = Θ. (c)…

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from article Chaos

Example of a pendulum in which gravity and a torsional ribbon act in opposition. The oscillating mass is a thin semicircular metal plate that is rigidly attached to the ribbon at its midpoint. The ribbon is fixed at each end but twists where the…

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from article Chaos

Simple fractal geometry attractors generated by computer. (a) Attractor generated using the Chirikov map defined by Eqs. (15), with c = 1.6 and initial values p0 = θ0 = 2. (b) Attractor generated using the torsion-gravity pendulum map defined by…

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from article Chaos

Examples of the period-doubling route to chaos for two vastly different iterative expressions. (a) The logistic map, defined by Eq. (18). (b) The Chebyshev root-finding algorithm applied to Kepler's equation, defined by Eqs. (20) and (21) with…

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from article Chaos

Power spectra of acoustic cavitation noise at four different excitation levels, showing the successive filling of the spectrum by period doubling (frequency halving) when the sound input intensity is raised. Numbers at tops of the graphs indicate…

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from article Chaos

Dependence of the scaled threshold field n40 F (10%) that produces an ionization probability of 10% after weakly bound hydrogen atoms are exposed to about 300 microwave field oscillations, on the scaled frequency n30ω.

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from article Power line communication

Broadband power line communication to homes.

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from article Catastrophe theory

Cusp catastrophe surface for the response function Vab as a function of (a,b) at a critical point. Paths A, B, and C are labeled.

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from article Catastrophe theory

Paths A, B, and C from Fig. 1, with points 1–10 marked. The response function Vab has the same values at (1,3,5) and at (2,4,10).

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from article Catastrophe theory

Paths that exhibit features of catastrophe theory. (a) Path on curve C showing a jump in the response function. (b) Path using curves A and B which shows hysteresis. No change in potential energy Vab is required to go from 1 to 3 or from 2 to 4. The…

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from article Aircraft instrumentation

Cockpit displays and flight engineer's instruments in Boeing 747. (Boeing Co.)

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from article Aircraft instrumentation

Flight deck mock-up of Boeing 767 configuration for crew of three. (Boeing Co.)

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from article Aircraft instrumentation

Ring laser gyro operation. (Honeywell, Inc.)

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from article Aircraft instrumentation

Electronic attitude-director indicator (EADI). (Boeing/Collins)

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from article Aircraft instrumentation

Electronic horizontal-situation indicator (EHSI) map mode. (Boeing/Collins)

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from article Aircraft instrumentation

Caution and warning display. (a) Configuration of elements. (b) Location of elements on aircraft instrument panel. (Boeing Co.)

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from article Aircraft instrumentation

Two-crew engine-indication and crew-alerting system (EICAS). (a) Configuration of the elements. (b) Location of the elements as they occur on an aircraft instrument panel. (Boeing Co.)

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from article Formation

Geological units of Paleozoic age recognized in the walls of the Grand Canyon, Arizona. (Modified from S. S. Beus, Geology along the South Kaibab Trail, eastern Grand Canyon, Arizona, in S. S. Beus, ed., Geological Society of America Centennial…

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from article Precipitation measurement

Automatic gages. (a) Tipping-bucket rain gage. (b) Weighing rain gage. (Belfort Instrument)

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from article Precipitation measurement

Comparison of rainfall rates measured with gages and radar using (a) the R, Z relation and (b) the R, KDP relation. Each data point (+) is the rainfall rate for a single storm.

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from article Trypanites

Trypanites borings in a carbonate hardground from the Upper Ordovician of northern Kentucky. The borings descend from the top of the rock surface perpendicularly to the bedding. Each boring is filled with tiny dolomite crystals, making them stand…

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from article Notoungulata

Skull and jaw of Adinotherium ovinum, an early Miocene toxodontid notoungulate from the Santa Cruz formation of Patagonia, Argentina.

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from article Notoungulata

Examples of molars of Adinotherium ovinum from the Santa Cruz formation of Patagonia, Argentina. (a) Upper molar. (b) Lower molar.

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from article Barometer

Type of mercury barometer used in meteorology.

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from article West Indies

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from article Packet switching

Communication network with five switching nodes interconnected by transmission facilities. Information arriving at the originating or source node can be switched to the destination node through a variety of possible end-to-end paths, for example,…

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from article Geoelectricity

Time variations of the horizontal orthogonal components of the natural (a) magnetic and (b) electric fields, simultaneously measured at one site at the surface.

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from article Geoelectricity

A vectogram representing a few minutes of recording of the natural electric field vector. The band-pass filter peaked at the 20-s period (0.05 Hz).

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from article Geoelectricity

Approximate and schematic frequencies and origins of the natural electromagnetic fields.

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from article Geoelectricity

Diurnal variations (solar plus lunar) of the horizontal component of the magnetic field, December 21, 1933, Huancayo, Peru. (After S. Chapman and J. Bartels, Geomagnetism. 2 vols., Oxford University Press, 1962)

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from article Geoelectricity

Amplitude spectra of the tellurograms shown in Fig. 2.

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from article Geoelectricity

Three components of the magnetic field of a magnetic storm of May 14, 1921, Potsdam, Germany. (After S. Chapman and J. Bartels, Geomagnetism, 2 vols., Oxford University Press, 1962)

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from article Andesine

Andesine plagioclase feldspar. Andesine is rarely found except as grains in igneous rocks. (Credit: Doug Sherman/Geofile)

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from article Ground-penetrating radar

Ground-penetrating radar equipment. (a) Portable equipment with 500-MHz antenna and controller that displays scrolling vertical slices of the soil in real time (USRADAR). (b) Portable equipment with 400-MHz antenna being used in archeological survey…

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from article Ground-penetrating radar

Radar cross-sectional image of reinforced concrete road. (ERA Technology UK)

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from article Ground-penetrating radar

Radar plan image of mines, area 0.9 by 1 m (3.0 by 3.3 ft). (ERA Technology UK)

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from article Ground-penetrating radar

Synthetic aperture radar (SAR) image of buried metal mines taken from an altitude of 400 m (1300 ft) above the Yuma desert. (Courtesy of R. Vickers, SRI, USA)

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from article Visual debugging

Visualizing a list in DDD.

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from article Visual debugging

Summarizing references in Jinsight.

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from article Extrapolation

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from article Radar

Multifunction phased-array radars. (a) One of the four planar faces of the radar of the AEGIS combat system, which is in use on many U.S. cruisers and destroyers (Lockheed Martin). (b) Pave Paws radar installation. (Raytheon Company)

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from article Radar

Air Force AWACS (Airborne Warning and Control System) in use. (a) AN/APY-1 rotodome installed. (b) Precision-array antenna of the AN/APY-1. (Northrop/Grumman Corp.)

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from article Radar

Block diagram of pulse radar. (a) Radar with a mechanically scanned antenna. (b) Radar with a phased-array antenna for electronic scanning. Array feed structure includes transmit distribution, receive beam forming, duplexing, and preamplification.…

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from article Radar

Effect of a reflecting Earth surface on the radiation pattern of an antenna. (a) Reflection nearly perfect. (b) Reflection much reduced.

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from article Radar

AN/FPS-16 tracking radar, a very accurate monopulse radar, operating in the C-band, installed at more than 50 sites around the world. (RCA Corp.)

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from article Radar

AN/SPS-49 search radar antenna, which forms a vertical fan beam for the two-dimensional L-band radar widely used in the U.S. Navy. (Raytheon Co.)

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from article Radar

Basic principle of electronic beam steering with a phased array. Equipath feed is for transmit or receive. All radiators radiate in essentially all forward directions. In beam steering, signals add in phase in the direction shown only if phase…

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from article Radar

Cathode-ray-tube radar display formats. (a) Type P (plan position indication, or PPI). Range is measured radially from center. (b) Type A. (c) Range-height indication (RHI).

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from article Sphere

Segment of a sphere formed by intersection of two parallel planes with sphere.

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from article Lamniformes

Representatives of the seven Lamniformes families. (a) Odontaspididae. (b) Mitsukurinidae. (c) Pseudocarchariidae. (d) Megachasmidae. (e) Alopiidae. (f) Cetorhinidae. (g) Lamnidae. (Illustration courtesy of J. S. Nelson, Fishes of the World, 4th…

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from article Lamniformes

Smalltooth sand tiger shark (Odontaspis ferox), a member of the family Odontaspididae in the order Lamniformes. (Photo courtesy of Ocean Explorer, Office of Ocean Exploration and Research, National Oceanic and Atmospheric Administration)

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from article Horst

Simple horst with associated faults. (After A. K. Lobeck, Geomorphology, McGraw-Hill, 1939)

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from article Agile methods in software engineering

Agile software engineering team. When agile methods were first proposed, many developers thought they were nothing more than an excuse to avoid the discipline and effort of traditional software engineering. Time has shown that agile methods require…

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from article Caliche

Typical profile through a mature caliche. The lower part of the profile is essentially a mimic of a juvenile caliche.

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from article Digital image processing

Computer vision application to find and identify hands. In this image, the hand, the fingers, and the joints have been identified.

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from article Digital image processing

Digital image processing can be separated into computer vision and human vision applications, with image analysis being important in both application areas.

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from article Digital image processing

Color image representation. A color image pixel consists of the red, green, and blue values. A color image is created by combining the red, green, and blue images.

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from article Digital image processing

Tools to aid in image analysis include segmentation and edge detection. (a) An original image. (b) The image after segmentation. (c) The image after edge detection.

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from article Digital image processing

Contrast enhancement can have a dramatic improvement on an image. (a) Poor-contrast image. (b) Contrast-enhanced image.

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from article Digital image processing

Image sharpening can bring out much more detail in an image. (a) Original image. (b) Image after the sharpening process.

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from article Modem

Signal conversion performed by modems. A modem converts a digital signal to an analog tone (modulation) and reconverts the analog tone into its original digital signal (demodulation).

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from article Modem

Use of modulation to encode a digital data stream into analog signals. (a) Amplitude modulation. (b) Frequency-shift keying, a type of frequency modulation. (c) Phase modulation. The bottom wave is 180° out of phase with a normal sine wave…

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