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from article Trilobita
Two iron-stained trilobites (Paradoxides) on a bedding plane slab from Morocco, North Africa, of Cambrian age. (Credit: Alan Morgan)
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Image
from article Trilobita
Trilobite diversity and preservation. (a) Olenellid, Lower Cambrian (British Columbia). External mold of exoskeleton in shale. (b) Ogygopsis, Middle Cambrian (British Columbia). Molt assemblage, with cranidium and pygidium aligned, but librigenae,…
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from article Trilobita
Morphological features of trilobites. (a) Calymene, Silurian (New York). Dorsal view of mineralized exoskeleton. (b) Phacops, Devonian (Ohio). Ventral (bottom) view of cephalon and anterior segments of the thorax, with hypostome attached. (c)…
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from article Trilobita
Triarthrus eatoni, Upper Ordovician (New York). Reconstruction with dorsal exoskeleton removed on right side to show appendages. Antennae are incomplete. Exites (gill branches) of the first nine postantennal appendages are removed to show the…
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from article Varistor
Symmetrical rectifier varistors. (a) Low voltage. (b) High voltage.
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from article Varistor
Equivalent circuit of a single-rectifier varistor.
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from article Forest fire
Exclusion of fire by humans has contributed to dramatic large blazes in the western United States. (Credit: Kari Greer)
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from article Forest fire
Crown fire in northern California. (Credit: Kari Greer)
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from article Forest fire
Values at risk during a forest fire can vary, depending on the location of the fire. (Credit: USDA Forest Service)
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from article Forest fire
Wildland firefighters work to separate the fuels on the ground from the fire in an effort to stop the spread of the fire. (Credit: Kari Greer)
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from article Forest fire
Engine crews work to suppress a large wildfire in northern California. (Credit: Kari Greer)
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from article Forest fire
Mega-fires often result in severe damage to natural resources and have long-lasting regional impacts. (Credit: USDA Forest Service)
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from article Forest fire
An example of fire prevention education: Smokey Bear. (Credit: USDA Forest Service)
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from article Forest fire
Lookouts in places where elevation and vision allow for a wide view of a broad expanse play an integral role in fire detection. (Credit: Kari Greer)
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from article Forest fire
Through a variety of management activities, societies seek to mitigate the impacts of wildfire. (A) Use of a masticator to reduce fuels. (B) Use of a low-intensity, prescribed (planned) fire to reduce the density of the vegetation, reduce fuels, and…
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from article Forest fire
Methods of fire suppression include hand crews, engine crews, and airborne intervention. While aircraft support firefighting efforts, forest fires are extinguished by ground-based firefighters. (Credit: USDA Forest Service)
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from article Forest fire
Extremely intense, fast moving forest fires can overwhelm even the most experienced, well-equipped firefighting workforce. (Credit: USDA Forest Service)
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from article Vertical/short takeoff and landing (V/STOL)
Cierva C.19 aircraft, at Musée de l'Air, Paris, 1981. (K. McKay)
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from article Vertical/short takeoff and landing (V/STOL)
Westland Lysander aircraft, at Duxford, U.K., 2010. (K. McKay)
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from article Vertical/short takeoff and landing (V/STOL)
Fairey Rotodyne compound autogyro. (Wikipedia)
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from article Vertical/short takeoff and landing (V/STOL)
Hunting H.126 jet flap research aircraft, at RAF Museum, Cosford, U.K. (K. McKay)
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from article Vertical/short takeoff and landing (V/STOL)
RR Pegasus engine. (Courtesy of RAF Museum, London)
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from article Vertical/short takeoff and landing (V/STOL)
Dornier 31 aircraft. (Courtesy of NASA)
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from article Vertical/short takeoff and landing (V/STOL)
CL-84 Dynavert aircraft, at National Aeronautical Collection, Ottawa. (K. McKay)
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from article Vertical/short takeoff and landing (V/STOL)
STOL aerodynamic concepts. (a) High-lift system blown by propeller wash. (b) Blown high-lift system using engine air bleed at flap knuckle. (c) High-lift system combined with engine thrust vectoring. (d) Blown high-lift system using engine air bleed…
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from article Vertical/short takeoff and landing (V/STOL)
Antonov An-76 aircraft at Farnborough Air Show, 1984. (K. McKay)
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from article Vertical/short takeoff and landing (V/STOL)
Hot gas ingestion mechanism.
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from article Vertical/short takeoff and landing (V/STOL)
Yak 141 aircraft at Farnborough Air Show, September 1992. (K. McKay)
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from article Vertical/short takeoff and landing (V/STOL)
Harrier II/Harrier GR.9 aircraft at Warton Air Show, December 2008. (K. McKay)
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from article Vertical/short takeoff and landing (V/STOL)
C-17 aircraft at RAF Fairford, July 2010. (K. McKay)
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from article Vertical/short takeoff and landing (V/STOL)
F-35B aircraft. (Courtesy of F-35 Lightning II Program, www.jsf.mil)
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from article Vertical/short takeoff and landing (V/STOL)
Rolls-Royce lift system for the F-35 aircraft. (Courtesy of F-35 Lightning II Program, www.jsf.mil)
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from article Vertical/short takeoff and landing (V/STOL)
MV-22 Osprey aircraft at RAF Fairford, July 2006. (K. McKay)
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from article Vertical/short takeoff and landing (V/STOL)
Bell-Agusta BA609 aircraft. (Courtesy of Agusta-Westland)
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from article Photoelasticity
Basic photoelastic polariscope.
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from article Photoelasticity
Isochromatic fringe pattern for plate with hole. (From M. M. Frocht, Photoelasticity, vol. 2, John Wiley and Sons, 1948)
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from article Radian measure
Diagrams showing radian measurement. Symbols are explained in the text.
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from article Cellulose
Microscopic view of cotton fibers, which contain 98% cellulose. (Credit: Martin Kreutz/agefotostock)
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from article Cellulose
Positioning of β-d-glucopyranosyl units in cellulose structure.
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from article Cellulose
Cellulose is the principal structural component of plants. In particular, cellulose in the plant cell wall is found mainly in the form of threadlike fibers, composed of smaller fibrils (microfibrils). (Copyright © McGraw-Hill Education)
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from article Thermionic power generator
Diagram of thermionic converter.
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from article Thermionic power generator
Motive diagrams of a thermionic converter operating in (a) ideal, (b) unignited, and (c) ignited modes.They give the spatial variation of the energy of an electron from emitter to collector. Here, φE and φC are emitter and collector work functions,…
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from article Thermionic power generator
Current density-voltage characteristics of a thermionic converter. VB is the barrier index; other symbols are as in Fig. 2.
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from article Neomeniomorpha
Gymnomenia virgulata Scheltema from a depth of 620 m (2000 ft) off Walvis Bay, Namibia. (a) Entire specimen, anterior to right, long cilia extending from the pedal pit. (b, c) Posterior and anterior ends, respectively. (d) Ventral view of a,…
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from article Chain drive
Roller chains. (a) Single-strand. (b) Triple-strand.
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from article Chain drive
Roller chain drive. (FMC Corp.)
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from article Chain drive
Engineering steel chain drive. (Rexnord Inc.)
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from article Chain drive
Inverted tooth/silent chain drive.
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from article Chain drive
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from article Z transform
Extraction of discrete-time sample values from a continuous signal.
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from article Lubricant
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from article Lubricant
Viscosity-temperature relationships indicated for additive-thickened multigrade oils. °C = (°F − 32)/1.8.
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from article Lubricant
Two examples of gear damage.
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from article Lubricant
Effect of dispersant on cleanliness. (a) Ordinary oil. (b) Oil containing dispersant additive.
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from article Lubricant
Useful temperature range of synthetic oils. °C = (°F − 32)/1.8.
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from article Lubricant
Electron micrographs showing (a) soap-thickened grease and (b) dye-thickened grease.
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from article Plants of saline environments
Desert arrowweed (Pluchea sericea) is a halophytic evergreen shrub adapted for growth in the salty basins of Death Valley, California. (Credit: Steven P. Lynch)
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from article Plants of saline environments
Soluble salts in irrigation water and those present in fertilizers lead to the gradual accumulation of toxic levels of sodium ions in topsoil, rendering the land useless. (Credit: Roberto A. Gaxiola)
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from article Plants of saline environments
Relationship between growth and sodium chloride concentration for halophytes and glycophytes. The diagram assumes that the plants are growing in a culture solution that accounts for about 10–20 mol m−3 of ions. (Copyright © McGraw Hill)
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from article Plants of saline environments
Suaeda maritima (annual sea blite), a halophytic member of the Chenopodiaceae. (Credit: František Pleva)
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from article Plants of saline environments
Gray mangrove (Avicennia marina) on the island of Tonga. Aerial roots called pneumatophores, which act as a snorkel, are growing out of the mud. Other mangroves can absorb air through holes in their bark known as lenticels. (Credit: Valentina…
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from article Plants of saline environments
Salt gland from the mangrove swamp species Aegiceras corniculatum. (a) Secretory cells surrounded by cuticle and epidermal cells. (b) Section through the gland. (Copyright © McGraw Hill)
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from article Monoplacophora
Living and fossil Monoplacophora. (a) Neopilina galatheae. (b) Tryblidium reticulatum. (After R. C. Moore, ed., Treatise on Invertebrate Paleontology, pt. I, 1957)
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from article Monoplacophora
Side views of various helcionellacean and bellerophont univalved mollusks. (a) Cyrtonellopsis; (b) Hypseloconus; (c) Cyclocyrtonella; (d) Stenotheca; (e) Bellerophon; (f) Tropidodiscus. (After B. Runnegar, Class Monoplacophora, in R. S. Boardman, A.…
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from article Landing gear
Landing gear arrangements. (a) Tail-wheel arrangement. (b) Tricycle arrangement.
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from article Landing gear
Main-wheel bogie for the XB-70A aircraft. (After S. Pace, North American Valkyrie XB-70A, Aero Series vol. 30, Tab Books, 1984)
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from article Gorgonacea
Gorgonian colonies in life. (a) Plumigorgia cf. hydroides, Palawan, Philippines. (b) Eunicella gracilis, São Tomé, Gulf of Guinea. (c) Junceella fragilis, Luzon, Philippines. (d) Leptogorgia alba, Cocos Island, Costa Rica. (e) Astrogorgia sp.,…
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from article Gorgonacea
Some common gorgonaceans. (a) Thouarella hicksoni (inset, detail of polyps). (b) Ideogorgia capensis. (c) Eunicella papillosa. (d) Leptogorgia lutkeni. (e) Junceella sp. (f) Anthothela parviflora. (g) Rumphella sp. (h) Homophyton verrucosum. (i)…
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from article Gorgonacea
Gorgonian colonies (dry preserved specimens). (a) Briareum sp. (b) Ideogorgia capensis. (c) Chrysogorgia pinnata. (d) Fanellia compressa. (e) Viminella sp. (f) Paragorgia sp. (g) Subergorgia suberosa. (h) Isis hippuris. (i) Solenocaulon sp.
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from article Gorgonacea
Caribbean gorgonian colonies (digital scans from dry preserved specimens). (a) Muricea cf. fruticosa. (b) Gorgonia ventalina. (c) Pseudopterogorgia cf. hummelincki.
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from article Gorgonacea
Gorgonian colonies (dry preserved specimens). (a) Leptogorgia palma. (b) Skeleton of Isidella sp. (Artwork courtesy of Jessica Machnicki, California Academy of Sciences)
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from article Gorgonacea
Gorgonian morphology.
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from article Instrumentation amplifier
Strain-gage bridge which produces a small wanted signal on a large bias, connected to an instrumentation amplifier that responds only to the wanted signal. The amplifier symbol indicates that the differential gain is controlled, unlike that of an…
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from article Instrumentation amplifier
Instrumentation amplifier topologies. (a) Simple topology based on three operational amplifiers. (b) Improved topology used in a modern integrated-circuit instrumentation amplifier.
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from article Automatic gain control (AGC)
Block diagram of a typical automatic gain control (AGC) circuit. (From J. R. Smith, Modern Communication Circuits, 2d ed., WCB/McGraw-Hill, Boston, 1998)
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from article Polycladida
Examples of body form in acotylean polyclads. (a) A more common oval shape with midventral mouth and pharynx (Stylochus ellipticus). (b) A less common ribbon shape with a posteriorly positioned mouth and pharynx (Latocestus whartoni). (Illustration…
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from article Polycladida
Anatomy of Pleioplana atomata, a common acotylean polyclad of temperate waters. (Illustration courtesy of L. H. Hyman)
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from article Polycladida
Cycloporus, a large cotylean polyclad with anal pores. (Illustration courtesy of L. H. Hyman)
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from article Hot-water heating system
One-pipe hot-water heating system.
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from article Hot-water heating system
Two-pipe reverse return system.
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from article Silver
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from article Mining
Gold and copper mine underground infrastructure in Australia. (Credit: Shutterstock/Alf Manciagli)
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from article Mining
Long sections of underground mines. (a) Ore body developed by adits. (b) Ore body developed by a shaft. (c) Bottom of stope prepared for horizontal ore movement. (d) Bottom of stope prepared by cone-shaped openings for ore movement.
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from article Mining
Long and cross sections of drill rounds. (a) Typical stope round. (b) Burn-cut round (drift), the 0 holes are left uncharged. (c) Drift round with top draw cut. (d) V-cut shaft round. (e) Sump or bench shaft round. The order of firing follows the…
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from article Mining
Loading principles. (a) Load-haul-dump unit. (b–e) Types of loading action: (b) filling bucket by shovel action; (c) filling backhoe bucket; (d) slusher bucket transporting; (e) filling clamshell bucket. (f) Scraper and gravity loading. (g)…
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from article Mining
Sections showing various types of support. (a) Deformation caused by forces. (b) Bolted cross section of level. (c) Timbered cross section of level. (d) Support in stopes. (e) Mine-waste support. (f) Timber support.
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from article Mining
Simplified electrical distribution system for mining.
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from article Mining
Radial electrical distribution system for an underground mine.
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from article Mining
Electrical distribution system for a surface mine.
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from article Mining
Open-pit mine power system.
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from article Mining
Horizontal ventilation plan for room-and-pillar coal mine.
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from article Mining
Ventilation circuits. Letters designate airways. (a) Series circuit. (b) Parallel circuit.
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from article Mining
Fan and mine operating point.
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from article Mining
Ventilation system in a southwestern Pennsylvania coal mine, showing the location of the shafts and slopes, and mine development.
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from article Mining
Homestake Gold Mine, showing the three primary ventilation circuits and major airways.
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from article Mining
Area required to be illuminated around a scoop used as a loading machine. Distance X is the distance from the side of the machine to rib or sidewall of the mine opening and is variable.
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from article Mining
Longwall illumination system showing area to be illuminated is from the face to the gob side of the travelway, which defines the path by which the miners operating the equipment move from one end of the longwall face to the other. Travelway A is…
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from article Mining
A quarry pit presents hazards from possible ground falls as well as massive equipment.
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from article Mining
At a coal mine rescue contest, a team member takes a gas reading as the team works through a hypothetical emergency.
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from article Mining
Sampling channel and chip channel in a zoned vein exposed at a mine face, with a sample from each zone.
