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from article Bridge maintenance
Under-bridge snooper truck during bridge inspection. (Courtesy Lian Duan)
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from article Bridge maintenance
Repair of concrete I-girder by replacement of damaged concrete.
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from article Bridge maintenance
Strengthening of a steel I-girder by adding new steel plates to flanges.
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from article Bridge maintenance
Strengthening a steel girder by applying external post-tensioning force.
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from article Bridge maintenance
A typical steel jacket for a reinforced-concrete column.
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from article Bridge maintenance
Built-up steel member retrofit. (Courtesy Lian Duan)
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from article Bridge maintenance
Seismic isolation bearing installed in the Antioch Bridge, California. (Courtesy Lian Duan)
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from article Bridge maintenance
A damper installed in the west span of the San Francisco–Oakland Bay Bridge, California. (Courtesy Lian Duan)
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from article Stereophonic radio transmission
Baseband spectrum of an FM stereo signal. This audio and supersonic spectrum is frequency-modulated onto a radio-frequency carrier.
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from article Video disk
DVD operational principles.
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from article Process control
Optimum operation of distillation column.
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from article Process control
Estimation of product quality by on-line computer.
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from article Process control
Block diagram illustrating feedback loop around process.
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from article Process control
Feedback and feedforward control on continuous stirred chemical reactor.
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from article Process control
Block diagram of typical feedforward control.
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from article Process control
Closed-loop fuzzy process control.
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from article Process control
Neural network for process modeling and control.
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from article Process control
Local computer system.
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from article Process control
Schematic example of modern distributed control system.
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from article Manganese
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from article Crystal growth
Schematic representation of cross section of crystal at three stages of regular growth.
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from article Crystal growth
A model of a crystal surface showing the inequivalent binding sites at which the atoms labeled A and B are located. (General Electric Co.)
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from article Crystal growth
A dendrite. Growth direction is upward for primary protuberances; side branches grow perpendicularly; side branches on the side branches are also seen growing perpendicularly. (After W. Kurz and D. J. Fisher, Fundamentals of Solidification, Trans…
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from article Crystal growth
Hypothetical binary system AB having simple compound formation. (a) Phase diagram. (b) Corresponding partial pressure curves. The extent of the stoichiometry range is greatly exaggerated for illustration.
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from article Crystal growth
Czochralski crystal growth and temperature distribution.
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from article Crystal growth
Vertical Bridgman crystal and temperature distribution.
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from article Crystal growth
An isotherm in the aluminum-gallium-arsenic (Al-Ga-As) ternary phase diagram. Each corner represents a pure element and each point within the diagram a unique composition, all at a given temperature. Each composition on the liquidus is in…
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from article Crystal growth
Molecular-beam epitaxy apparatus.
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from article Crystal growth
Cross section of a gallium arsenide–aluminum arsenide (GaAs–AlAs) single crystal with individual gallium arsenide and aluminum arsenide layers each about 5 × 10−10 m thick.
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from article Animal virus
Electron micrograph of negatively stained, purified bovine papilloma virions with icosahedral symmetry. (Credit: David Hill and John P. Sundberg)
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from article Animal virus
Electron micrograph of a thin section of chicken cells containing crystalline inclusion bodies formed by an avian reovirus during infection. (Credit: David Hill and John P. Sundberg)
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from article Risk assessment and management
Risk management and assessment involves solving problems such as the lifetime risk of occupational exposure to radiation from nuclear power reactors. (Copyright © Philip Lange/Shutterstock.com)
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from article Risk assessment and management
Risk analysis, assessment, and management.
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from article Stripping (chemical engineering)
Stripping column and accessory equipment.
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from article Stripping (chemical engineering)
Column operating diagrams. (a) Absorption. (b) Stripping.
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from article Phase-locked loops
Basic components of a phase-locked loop.
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from article Phase-locked loops
Diode phase detector.
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from article Phase-locked loops
Double-balanced phase detector. (a) Circuit. (b) Waveforms.
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from article Phase-locked loops
Digital phase/frequency detector. Q = output; Q = inverting output.
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from article Phase-locked loops
Loop filter configurations. (a) Passive. (b) Active.
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from article Airborne radar
Radar presentation showing a squall line extending from northwest to southeast. The range marks, indicating 5-mi (8-km) units, give estimation of extent of disturbance. (RCA Corp.)
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from article Airborne radar
High-resolution radar map of a golf course near Stockbridge, New York. (M.I.T.-Lincoln Laboratory)
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from article Mixer
Linear mixers. (a) Passive linear mixer based on a resistive summing network. (b) Active linear mixer with an operational amplifier.
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from article Mixer
Balanced modulator (nonlinear mixer). Only signal paths are shown. Biasing must be added.
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from article Sol-gel process
Flow chart showing the sol-gel methods used to prepare bulk glasses, thin films of glass or ceramics, and powders; the powders are then sintered to produce ceramics.
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from article Tick virus diseases
A deer or black-legged tick (Ixodes scapularis). (Credit: U.S. Centers for Disease Control and Prevention)
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from article Tick virus diseases
Diagram depicting the life cycle of Ixodes scapularis. This deer tick can transmit viruses and other pathogens that cause a number of important diseases, including Lyme disease, anaplasmosis, and babesiosis. The risk of human infection is greatest…
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from article Tick virus diseases
World map depicting the locations of human tick-borne disease cases. Heartland, Bourbon, and Colorado tick fever virus cases are unique to North America. Powassan encephalitis cases are reported in North America and Russia. Tick-borne encephalitis…
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from article Tick virus diseases
Cases of Powassan encephalitis reported in the United States from 2006 to 2015. Most of the reported cases are in Minnesota, New York, and Wisconsin. (Credit: ArboNET, Arboviral Diseases Branch, U.S. Centers for Disease Control and Prevention)
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from article Anaerobic infection
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from article Systems integration
Systems integration activity, showing the architecture for the system.
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from article Systems integration
Tactical and strategic perspective of systems integration, showing essential elements.
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from article Degenerative neural diseases
Factors leading to degenerative neural diseases. Abbreviations: AD, Alzheimer's disease; AD/PD, Alzheimer's disease with parkinsonism; ALS, amyotrophic lateral sclerosis; DLB, dementia with Lewy bodies; FTD, frontotemporal dementia; MID,…
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from article Straight-line mechanism
Classical four-bar linkage straight-line mechanisms: (a) Watt, (b) Russell, (c) Evans, (d) Roberts, (e) Chelbyshev, (f) Peaucellier.
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from article Straight-line mechanism
Geared straight-line mechanisms. (a) Cardan circle pair; small-gear diameter = 0.5 large-gear diameter. (b) Standard gear; gear diameter 2 = 0.5 gear diameter 1; gear diameters 3 and 4 are arbitrary.
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from article Straight-line mechanism
Translating follower cam mechanism with an instantaneously equivalent slider-crank representation.
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from article Straight-line mechanism
Chain/belt–sprocket combination.
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from article Supercritical wing
Comparison of airflow about airfoils. (a) Conventional airfoil, Mach number = 0.7. (b) Supercritical airfoil, Mach number = 0.8
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from article Hepaticopsida
Jungermanniidae, the leafy liverworts. (a) Herberta, showing three ranks of equal bifid leaves. (b) Lepidozia, ventral aspect, showing reduced ventral leaves. (c) Leucole jeunea, ventral aspect, showing reduced ventral leaves and complicate dorsal…
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from article Hepaticopsida
Diagram of life cycle of the liverwort Marchantia, indicating stages at which chromosome changes occur. (After H. J. Fuller, The Plant World, rev. ed., Holt, 1951)
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from article Hepaticopsida
Transverse sections through the thallus of Marchantia. (a) Middle portion with scales and rhizoids on the underside. (b) Margin of the thallus more highly magnified. (After H. Kraemer, Applied and Economic Botany, 2d ed., Wiley, 1916)
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from article Hepaticopsida
Marchantia. (a) Example of male gametophyte (antheridial plant) (after H. J. Fuller and O. Tippo, College Botany, Holt, 1949). (b) Section through an antheridial receptacle (after W. J. Robbins and H. W. Rickett, Botany, 3d ed., Van Nostrand, 1939).
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from article Hepaticopsida
Marchantia. (a) Example of female gametophyte (archegonial plant) (after H. J. Fuller and O. Tippo, College Botany, Holt, 1949). (b) Section through an archegonial receptacle (after W. J. Robbins and H. W. Rickett, Botany, 3d ed., Van Nostrand,…
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from article Hepaticopsida
Marchantia sporophyte morphology. (a) Mature archegonial receptacles of sporophytes (after W. J. Robbins and H. W. Rickett, Botany, 3d ed., Van Nostrand, 1939). (b) Marchantia polymorpha, longitudinal section showing the internal structure of a…
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from article Hepaticopsida
Structures involved in vegetative reproduction of Marchantia. (a) Portion of surface of the thallus. Note gemma cup with gemmae (after H. J. Fuller and O. Tippo, College Botany, Holt, 1949). (b) Notched, lens-shaped gemma of M. polymorpha (after G.…
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from article Electric transient
Resistance and inductance in series.
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from article Electric transient
Resistance and capacitance in series.
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from article Electric transient
Resistance, inductance, and capacitance in series for three cases.
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from article Electric transient
RLC circuit with alternating current source.
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from article Electric transient
Causes of electric transients in power systems.
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from article Electric transient
Analysis of electric transients involving both harmonic oscillation and traveling waves. (a) Configuration of power system for study of transient recovery voltage (TRV). (b) Model for evaluating steady state before breaker opening. (c) Model for…
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from article Electric transient
Graphical interpretation of electromagnetic transients on transmission line. (a–f) Voltage profiles along line. (g) Derived voltage at beginning of line as a function of time.
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from article Electric transient
Transient recovery voltages (TRVs). (a) TRVs on source side (vS) and line side (vl). (b) TRV across circuit breaker (vB).
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from article Electric transient
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from article Ergot and ergotism
Ergot life cycle. Parts a–d explained in text.
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from article Exotic viral diseases
A colorized negative stained transmission electron micrograph depicting a number of Marburg virus virions. Marburg virus disease is a rare, exotic viral disease that affects both humans and nonhuman primates. (Credit: Frederick A. Murphy/Centers for…
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from article Wi-Fi
802.11 WiFi wireless router (access point). (Credit: Copyright © Sheval/Alamy)
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from article Wi-Fi
Wireless LAN architectures. (a) Independent basic service set. (b) Infrastructure basic service set. (c) Extended service set.
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from article Wi-Fi
Sending a data frame using carrier-sense multiple access with collision avoidance (CSMA/CA).
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from article Wi-Fi
Hidden-node problem for a wireless network.
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from article Turnip
Purple Top turnip (Brassica rapa). (Credit: Stami Kieren Donovan; courtesy of Greenpatch Organic Seeds, Glenthorne, New South Wales, Australia)
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from article Dill
Flowering of dill (Anethum graveolens). (Photo courtesy of Forest and Kim Starr)
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from article Ferrite devices
Plot of magnetic induction B as a function of magnetic field strength H.
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from article Ferrite devices
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from article Subsonic flight
Flow around an airfoil (a) without circulation and (b) with circulation.
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from article Subsonic flight
Flow occurring at small Reynolds numbers (a) around a circular cylinder and (b) around an elliptical cylinder. (From L. Prandtl and O.G. Tietjens, Applied Hydro- and Aeromechanics, Dover, 1934)
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from article Subsonic flight
Flow pattern on an airfoil in a real fluid. (a) Low angle of attack, unstalled. (b) High angle of attack, stalled. (From P. P. Ewald, T. Poschl, and L. Prandtl, Physics of Solids and Fluids, Blackie, 1936)
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from article Subsonic flight
Dimensionless laminar boundary layer and turbulent boundary layer profiles.
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from article Subsonic flight
Boundary-layer growth on a sphere for R > 550,000. The boundary-layer thickness is exaggerated in the diagram for clarity. ( After J. H. Dwinnell, Principles of Aerodynamics, McGraw-Hill, 1949)
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from article Subsonic flight
Representation of a rectangular wing by a horseshoe vortex.
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from article Fiber crops
Cotton, the most important textile fiber crop grown in the world. (Photo by Gary Kramer, Natural Resources Conservation Service, U.S. Department of Agriculture)
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from article Pantograph
Similar triangles of a pantograph.
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from article Parametric amplifier
Negative-resistance-type parametric amplifier.
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from article Valve train
Valve for a four-cycle engine. (a) Valve-timing diagram. (b) Valve train with the camshaft in the cylinder block and the valves in the cylinder head. (Pontiac Division, General Motors Corp.)
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from article Valve train
Valve train of a V-6 four-cycle engine with the valves and two camshafts located in each cylinder head. The cams act directly on cup-type cam followers to open the valves. (Ford Motor Co.)
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from article Lignin
Chemical formula representation of lignin, in which bold lines represent linkages between individual phenylpropane lignin monomer units, and shaded area represents the structure of a typical lignin model compound.
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from article Coal liquefaction
Processing steps in direct coal liquefaction. Broken lines represent optional steps or flow streams.
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from article Toxin
Bacteria, such as Clostridium perfringens, often produce exotoxins that have deleterious effects on other organisms. Clostridium perfringens can cause foodborne disease by contamination of raw food materials. (Credit: Don Stalons/Centers for Disease…
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from article Toxin
Taiwan banded krait (Bungarus multicinctus). Certain elapid snakes known as kraits produce a venom that contains bungarotoxins, which are potent neurotoxins. (Credit: LiCheng Shih)
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from article Tree diseases
White pine blister rust (Cronartium ribicola) on eastern white pine (Pinus strobus). The blisters are masses of aeciospores (rust spores). (Photo courtesy of the Minnesota Department of Natural Resources Archive)
