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from article Deep inelastic collisions

Deep inelastic collision between an electron and a proton, where the nucleon is viewed either (a) as a blob that breaks up or (b) as composed of quarks, one of which is ejected by elastic scattering with the electron.

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from article Optical prism

Optical prism, consisting of a refracting medium bounded by two surfaces. Dispersion of light into its component colors is shown. (After W. J. Smith, Modern Optical Engineering, 3d ed., SPIE Press–McGraw-Hill, 2000)

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from article Optical prism

System of two Porro prisms, used to invert the image in traditional binoculars. (After R. E. Hopkins and R. Hanau, U.S. Military Handbook for Optical Design, republished by Sinclair Optics, 1987)

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from article Optical prism

Pentaprism, used in single lens reflex cameras. (a) Perspective view, showing how the prism deviates light through an angle of 90° without inverting or reverting the image. (b) Ray diagram. (After R. E. Hopkins and R. Hanau, U.S. Military Handbook…

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from article Optical prism

Set of two thin prisms, known as optical wedges, which can be used as an alignment device. (After P. R. Yoder, Jr., Non-image forming optical components, in Geometrical Optics, SPIE Proc., 531:206–220, 1985)

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from article Circle

A circle, with radius, diameter, and circumference indicated. (Credit: McGraw-Hill Education)

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from article Circle

Nine-point circle and Euler line PMH.

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from article Sonobuoy

Launch of a sonobuoy from an antisubmarine warfare (ASW) aircraft. (a) In flight. (b) Buoy strikes the water in a nearly vertical attitude. (c) Antenna and hydrophone are positioned automatically.

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from article J/psi particle

Online data from August and October 1974, showingexistence of J/psi particle. (After J. J. Aubert et al., Discovery of the new particle, J. Nuc. Phys., B89(1):1–18, 1975)

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from article Trihedron

Trihedron and trihedral angles.

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from article Trihedron

Spherical triangle ABC formed by intersection of sphere with a trihedron. The center of the sphere is at the vertex of the trihedron.

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from article Electric filter

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from article Electric filter

Passive, lumped-element filters. (a) RC low-pass filter. (b) LC band-pass filter.

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from article Electric filter

Ladder structure. (a) Overall structure with alternating series and shunt arms. (b) LC circuit whose impedance contains both a finite-frequency pole and a zero. Such circuits are used in the series and shunt arms of the ladder structure.

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from article Electric filter

Mechanical filter.

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from article Electric filter

Single-amplifier filters. (a) Low-pass Sallen-Key filter. (b) Low-pass, infinite-gain, single-amplifier filter. (c) Cascade of second-order filter realizations.

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from article Electric filter

Multiple-amplifier filters. (a) State-variable (KHN) filter. (b) Tow-Thomas filter.

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from article Electric filter

Simulated-inductor realization of fifth-order high-pass filter. (a) RLC prototype, normalized for cutoff frequency of 1 rad/s (0.159 Hz). (b) Direct active-RC realization.

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from article Satellite television broadcasting

Direct broadcasting television satellite system.

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from article Helmholtz coils

Helmholtz coils, arranged with common axis and connected in series. (After L. B. Loeb, Fundamentals of Electricity and Magnetism, 3d ed., Wiley, 1947)

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from article Helmholtz coils

Separate and combined fields of Helmholtz coils. Note the region of constant resultant field at point P. (After L. B. Loeb, Fundamentals of Electricity and Magnetism, 3d ed., Wiley, 1947)

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from article Gamma function

Depiction of gamma function Γ(z) for real values of z.

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from article Human-factors engineering

Human-factors engineers design modern computer equipment, including ergonomic keyboards and mouse devices, to accommodate the varied physical contours and dimensions of the human hand. (Credit: JG Photography/Alamy)

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from article Human-factors engineering

Human-factors engineering addresses problems related to the design of seats, workplaces, and consoles in terms of a user's physical size, comfort, strength, and visibility. (Copyright © McGraw-Hill Education)

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from article Human-factors engineering

Cognitive engineering and the development of new technology applications.

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from article Skin friction

Sketch of boundary-layer flow over a flat plate. Here, u is the component of fluid velocity parallel to the plate surface, which reaches u∞ at the edge of the boundary layer. (From J. P. Holman, Heat Transfer, 10th ed., McGraw-Hill, 2010)

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from article Skin friction

Skin-friction coefficient for flow of Newtonian fluids over flat plates. (a) Low-Reynolds-number regime. The curved lines are based on the solutions of C. W. Oseen, H. Blasius, and I. Imai to equations for viscous flow, and the symbols are data.…

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from article Skin friction

Skin-friction coefficient for flow of Newtonian fluids over rough flat plates. (Adapted from F. M. White, Fluid Mechanics, 8th ed., McGraw-Hill, 2016)

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from article Skin friction

Placoid scales (dermal denticles) of a lemon shark, viewed through a scanning electron microscope. (Credit: Pascal Deynat/Odontobase)

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from article Skin friction

Pressure drop for Newtonian fluids in smooth and uniformly rough pipes. The dimensionless measure of the pressure drop, λ, is given in Eq. (6); D is the pipe diameter, and ∊ is the average size of the roughness. (From L. F. Moody,Friction factors…

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from article Skin friction

Pressure drop for power-law, non-Newtonian fluids in smooth pipes. The dimensionless measure of the pressure drop, λ, is given in Eq. (6); and D is the pipe diameter. (Adapted from D. W. Dodge and A. B. Metzner, Turbulent flow of non-Newtonian…

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from article Isotope separators

Illustration of how a dipole magnet provides separation by rigidity for a beam of ions passing through it. The higher-rigidity particle, isotope A, is less deflected by the dipole field and follows the circular path through the dipole with the…

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from article Isotope separators

Part of the A1900 fragment separator as seen during its construction at the National Superconducting Cyclotron Laboratory, located at Michigan State University. The person near the center is perched in front of one of the device's four dipole…

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from article Isotope separators

Layout of the National Superconducting Cyclotron Laboratory (NSCL), which is being upgraded to the Facility for Rare Isotope Beams (FRIB).

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from article Isotope separators

Installation of the high-efficiency gamma-detection and -tracking array GRETINA for use at the target position of the S800 spectrograph at the NSCL. Visible near the bottom at the center is the spherical mounting frame used to hold the germanium…

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from article Relativity

Albert Einstein, photographed in 1947. (Credit: Library of Congress)

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from article Relativity

According to general relativity, the four-dimensional construct of reality, called spacetime, is warped by the massive objects, such as the Sun and Earth, illustrated in the depressions in the green grid. General relativity's description of gravity…

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from article Relativity

Spacetime diagram illustrating the causal relationships with respect to an event, A, in prerelativity physics. Event B lies to the past of A, event C lies to the future of A, and event D is simultaneous with A.

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from article Relativity

Spacetime diagram illustrating the causal relationships with respect to an event, A, in special relativity. Event B lies to the past of A, event C lies to the future of A, and events D and E are spacelike-related to A.

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from article Relativity

Einstein′s elevator, illustrating the principle of equivalence. The elevator acceleration is equal to g, the acceleration of gravity.

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from article Relativity

A diagram of gravitational lensing, in which a foreground galaxy cluster bends the light from a distant, background galaxy on its way to Earth. (Credit: NASA/ESA)

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from article Relativity

An aerial view of the LIGO observatory in Livingston, Louisiana, one of two such detectors in the United States, with the second located in Hanford, Washington. Two observatories are needed to provide a cross-check against local disturbances that…

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from article Relativity

Gravitational collapse. (a) From the point of view of a distant observer, the surface of a collapsing star approaches the Schwarzschild radius Rs or black hole surface. (b) As seen by an observer riding on its falling surface, it collapses through…

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from article Relativity

Two-dimensional analogs of the three-dimensional space of the universe. At top, the sphere is positively curved, with a value greater than 1 for omega, or the ratio of the actual density of the universe to its critical density, the latter of which…

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from article Magnet

A magnetic dipole, consisting of a north magnetic pole (red "N") and a south magnetic pole (silver "S"). Iron filings affected by the magnet reveal magnetic field lines, which converge at the poles. (Credit: Alchemy/Alamy)

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from article Magnet

A lodestone attracting a metal paperclip. (Credit: neal and molly jansen/Alamy)

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from article Josephson effect

DC current-voltage characteristics of lead-lead oxide-lead Josephson tunnel junction at 1.2 K. (a) Without microwave power. (b) Same characteristic with reduced scale. (c) 11-GHz microwave power applied. (d) Expanded portion of c; arrow indicates a…

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from article Josephson effect

Magnetic field dependence of the critical current of a Josephson tunnel junction. Data are for a tin-tin oxide-tin junction at 1.2 K, with the magnetic field in the plane of the barrier. (After D. N. Langenberg, D. J. Scalapino, and B. N. Taylor,…

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from article Josephson effect

Some types of Josephson junctions. (a) Thin-film tunnel junction. (b) Point contact. (c) Thin-film weak link. (After E. Burstein and S. Lundqvist, eds., Tunneling Phenomena in Solids, Plenum, 1969)

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from article Josephson effect

DC current-voltage characteristics for a weak link and a tunnel junction. (After E. Burstein and S. Lundqvist, eds., Tunneling Phenomena in Solids, Plenum, 1969)

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from article Absorption

Incident sunlight is absorbed, reflected, and scattered by tree leaves. (Credit: Shutterstock / photolinc)

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from article Negative temperature

Populations (n) of states of a thermodynamic system consisting of N magnetically interacting nuclei of spin 2 at absolute temperatures T = +D/k and T = −D/k, where k is Boltzmann's constant and D is the energy spacing between successive states.

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from article Luminescence

Schematic representation of energy levels and electronic transitions in an atomic gas. E1, ground state; E2 and E3, excited states; 1, excitation; 2, emission of resonance luminescence; 3, radiationless transition to lower excited state; 4,…

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from article Luminescence

Configuration coordinate curves for a simple luminescence center. Transition A → B shows absorption, and transition C → D shows emission. Energy EQ is that necessary for the excited state to reach point E, from which a transition to the ground state…

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from article Luminescence

Variation of the brightness of a thallium-activated potassium chloride phosphor with temperature. °F = (K × 1.8) − 459.67.

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from article Luminescence

Variation of the width of the F-center absorption band in potassium chloride at its half-maximum points, FE, as a function of the square root of the temperature. °F = (K × 1.8) − 459.67.

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from article Luminescence

Emission of thallium-activated potassium chloride at 4 K (−452°F). In a plot of this particular form, a gaussian curve would consist of two straight lines which make equal angles with the abscissa.

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from article Luminescence

Graph showing the absorptance (100 minus percent of transmission) and edge emission of cadmium sulfide at 4 K (−452°F).

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from article Luminescence

Excitation spectra for emission of calcium carbonate phosphors, using manganese as an activator, with different impurity sensitizers: 1, no sensitizer; 2, thallium; 3, lead; and 4, cerium.

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from article Luminescence

Energy-band model for luminescence processes in zinc sulfide. Electron energy increases vertically.

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from article Luminescence

Energy-band model for luminescence processes in zinc sulfide which uses copper as the activator and aluminum as the coactivator.

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from article Yeast

Colorized scanning electron micrograph (SEM) of Schizosaccharomyces pombe yeast. This single-celled fungus is studied widely as a model organism for eukaryotic cell division. It is a rod-shaped yeast that grows by elongation at its ends, and it…

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from article Yeast

Cell shapes of yeasts are extremely varied: (a) rectangular; (b) pear-shaped; (c) apiculate; (d) ogival; (e) spherical; (f) globose; (g) ellipsoidal (oval); (h) elongate; (i) tetrahedral. (Copyright © McGraw Hill)

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from article Yeast

Colorized scanning electron micrograph (SEM) of cells of brewer's yeast (Saccharomyces cerevisiae). This yeast consists of single vegetative cells. Small daughter cells can be seen budding off from the larger cells. Saccharomyces cerevisiae ferments…

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from article Yeast

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from article Yeast

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from article Yeast

A fluorescent antibody stain reveals the oval budding yeast cells of Candida albicans. This yeast is the most common human fungal pathogen. (Credit: Maxine Jalbert and Leo Kaufman/Centers for Disease Control and Prevention)

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from article Beer

Grains of (a) barley before malting and (b) hop plant. (Credit: U.S. Department of Agriculture)

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from article Beer

Fermentation tanks. (Credit: ClarkandCompany/Getty Images)

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from article Peppermint

Peppermint (Mentha piperita). (Credit: Michael Thompson/Agricultural Research Service, U.S. Department of Agriculture)

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from article Magnification

Illustration of the view through a magnifying glass increasing the visible size of a portion of a fingerprint. (Credit: Federal Bureau of Investigation)

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from article Quantized electronic structure (QUEST)

Geometric configurations of (a) quantum well, (b) quantum wires, and (c) quantum dots.

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from article Quantized electronic structure (QUEST)

Electron energy levels and electron standing waves for n = 1, 2, 3, and 4 quantum states in a quantum well.

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from article Quantized electronic structure (QUEST)

Principles of operation of quantum-well devices. (a) Quantum-well laser. (b) Quantum-well infrared detector. (c) High-electron-mobility transistor (HEMT or MODFET). Electrons in the quantum well that came from donor atoms in the barrier are free to…

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from article Citron

Citron (Citrus medica), including cross sections of the fruit. (Photo courtesy of California Citrus Clonal Protection Program)

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from article Foodborne disease

Trichrome-stained photomicrograph of a Giardia lamblia trophozoite (a growing stage in the life cycle of certain protozoan parasites). This microorganism often causes giardiasis (a diarrheal foodborne illness). (Credit: Melanie Moser/Centers for…

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from article Foodborne disease

A cluster of norovirus particles. (Credit: Charles D. Humphrey/Centers for Disease Control and Prevention)

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from article Foodborne disease

Colored scanning electron micrograph showing Salmonella enterica bacteria (serotype Typhimurium; colorized red) invading an immune cell (colorized yellow). This bacterial species commonly causes food-associated gastroenteritis. (Credit: National…

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from article Foodborne disease

Close-up view of Campylobacter jejuni bacteria. This scanning electron microscope image shows the characteristic spiral (or corkscrew) shape of C. jejuni cells. (Credit: De Wood and Chris Pooley/Agricultural Research Service, U.S. Department of…

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from article Flow of granular solids

Bounds on mass flow and funnel flow. (a) Geometry of a transition hopper, showing slope angles θc and θp. (b) Range of kinematic angle of friction (ϕ′) and θc leading to mass flow and funnel flow. (c) Range of ϕ′and θp leading to mass flow and…

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from article Flow of granular solids

Flow patterns in a funnel-flow bin, showing segregation of solids. (a) Charge coming in is greater than draw coming out, resulting in draw with a preponderance of fine particles. (b) Draw is greater than charge, resulting in draw with a…

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from article Flow of granular solids

Section of bin with mass-flow conical hopper, together with graph showing relative values of pressure p, compressive strength f, and stress s, and illustrating criterion (f = s) for minimum outlet dimension B. (After A. W. Jenike, Quantitative…

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from article Spray flow

Cross section of a vaporizing droplet, showing the relative gas-droplet motion and internal circulation.

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from article Atmospheric acoustics

Frequency dependence of attenuation coefficient in units of decibels per 100 m (dB/328 ft), temperature of 20°C (68°F), and a relative humidity of 70%. Total attenuation from air absorption and contributions from classical absorption (that due to…

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from article Atmospheric acoustics

Diagram of reflection of sound from a flat ground surface with impedance Z, showing direct (R1) and reflected (R2) paths from source to receiver, source height hs, microphone height h, distance of propagation d, and angle of incidence or grazing…

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from article Atmospheric acoustics

Relative sound pressure levels (SPL) for propagation from a source over mown grass for source height of 1.8 m (6 ft), microphone height of 1.5 m (5 ft), and distances of propagation indicated.

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from article Atmospheric acoustics

Curved ray paths. (a) Refraction downward, during temperature inversion or downwind propagation. (b) Refraction upward, during temperature lapse or upwind propagation.

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from article Atmospheric acoustics

Representative long-range ray paths of sound radiating from a source in the atmosphere and traveling from west to east in Northern Hemisphere in winter. 1 km = 0.6 mi. (After T. F. Malone, ed., Compendium of Meteorology, American Meteorological…

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from article Atmospheric acoustics

Contour plot of sound levels in the presence of upward refraction in a turbulent atmosphere. The source is very close to the ground at zero range. The white areas are regions of higher sound levels.

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from article Atmospheric acoustics

Facsimile record of acoustic echo sounding of atmosphere at the South Pole, February 9, 1975. 300 m = 984 ft, 600 m = 1969 ft. Dark regions above 300 m altitude correspond to temperature inhomogeneities associated with the passage of convective…

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from article Surface waves

Definition sketch for an oscillatory wave.

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from article Surface waves

Fluid particle orbital motions in deep-and shallow-water oscillatory waves. SWL = still-water level.

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from article Surface waves

Definition sketch for a solitary wave. SWL = still-water level.

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from article Surface waves

Definition sketch for a surge wave.

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from article Astrapotheria

Skeleton of Astrapotherium magnum. The genus Astrapotherium is known from the late Oligocene to the late Miocene.

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from article Lycopsida

Lycopodium clavatum, a representative homosporous lycopsid. (a) Sporophyte showing typical rhizomatous growth and paired cones. (b) Microphyllous leaf. (c) Sporophyll bearing a sporangium on the upper surface. (From K. R. Sporne, The Morphology of…

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from article Ising model