- 行业: Printing & publishing
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- Company Profile:
McGraw Hill Financial, Inc. is an American publicly traded corporation headquartered in Rockefeller Center in New York City. Its primary areas of business are financial, publishing, and business services.
A controller that measures and controls relative humidity. A humidistat may be used to control either humidifying or dehumidifying equipment by the regulation of electric or pneumatic switches, valves, or dampers. Most methods for measuring humidity rely upon the swelling and shrinking of materials, such as human hair, silk, horn, gold-beater's skin, and wood, with increases and decreases in relative humidity.
Industry:Science
A convective storm accompanied by lightning and thunder and a variety of weather such as locally heavy rainshowers, hail, high winds, sudden temperature changes, and occasionally tornadoes. The characteristic cloud is the cumulonimbus or thunderhead, a towering cloud, generally with an anvil-shaped top. A host of accessory clouds, some attached and some detached from the main cloud, are often observed in conjunction with cumulonimbus. The height of a cumulonimbus base above the ground ranges from 1000 to over 10,000 ft (300 to 3000 m), depending on the relative humidity of air near the Earth's surface. Tops usually reach 30,000–60,000 ft (9000–18,000 m), with the taller storms occurring in the tropics or during summer in midlatitudes. Thunderstorms travel at speeds from near zero to 70 mi/h (30 m/s). In many tropical and temperate regions, thunderstorms furnish much of the annual rainfall.
Industry:Science
A convenient graphical representation of input-output behavior of a system or subsystem, where the signal into the block represents the input and the signal out of the block represents the output. The flow of information (the signal) is unidirectional from the input to the output. A complex system, comprising several subsystems, is represented by the interconnection of blocks that represent the subsystems. The primary use of the block diagram is to portray the interrelationship of distinct parts of the system.
Industry:Science
A conveyor is a moving belt that transports objects from one place to another. Commonly seen on a small scale at grocery store checkouts or airport baggage claims, belt conveyors have thousands of uses in most industries worldwide. In the mining industry, 95% of all the materials mined are transported from one place to another on conveyors.
Industry:Science
A cool and highly luminous star, prominently located in the right shoulder of the constellation Orion and noticeably red in color. Betelgeuse, or α Orionis, is a supergiant star about 130 parsecs (430 light-years) from the Sun. Its spectral type of M2 indicates an effective temperature of approximately 3500 K (5800°F). This temperature would result in a low overall luminosity were it not for the enormous diameter of the star, about 1100 times that of the Sun. Replacing the Sun, Betelgeuse would fill the solar system to beyond the orbit of Mars. Betelgeuse is a supergiant star with approximately 150,000 times the Sun's luminosity. Betelgeuse varies in brightness with a period of 6.4 years. Its mean density is extremely low, less than one-millionth the density of water, and the low surface gravity of the rarefied outer layers results in a continual loss of matter, presently at the rate of 1 solar mass every 250,000 years. Observations at infrared and radio wavelengths show a complex system of dust and gas shells extending out as far as a thousand stellar radii. If this material were visible to the eye, Betelgeuse would appear as large as Mars through a telescope. These shells appear to originate from occasional outbursts in which material is ejected and eventually merges with the interstellar medium.
Industry:Science
A cool red giant star, prominently located in the constellation Taurus. With its red color, it appropriately represents the eye of the Bull. At a distance of 18.5 parsecs (60 light-years), Aldebaran, or α Tauri, is among the nearest (and brightest) giant stars to the Sun. It appears to be situated near the middle of the Hyades, but Aldebaran is actually less than half the distance of this nearby star cluster. The star is an example of a K-type giant, a very common type of evolved star that derives its energy from the thermonuclear burning of helium in a core surrounded by a thin, hydrogen-burning shell. Its spectral type of K5III corresponds to an effective temperature of 6700°F (4000 K) and a radius of about 40 times the Sun. It is nearly 150 times more luminous than the Sun and, as is typical for K giants, its brightness varies by a modest amount. Aldebaran is accompanied in a long-period binary-star system by a cool dwarf companion star some 100,000 times fainter than the giant.
Industry:Science
A cooling system in an internal combustion engine that is used to maintain the various engine components at temperatures conducive to long life and proper functioning. Gas temperatures in the cylinders may reach 4500°F (2500°C). This is well above the melting point of the engine parts in contact with the gases; therefore it is necessary to control the temperature of the parts, or they will become too weak to carry the stresses resulting from gas pressure. The lubricating oil film on the cylinder wall can fail because of chemical changes at wall temperatures above about 400°F (200°C). Complete loss of power may take place if some spot in the combustion space becomes sufficiently heated to ignite the charge prematurely on the compression stroke.
Industry:Science
A cool-season annual or biennial crucifer, <i>Raphanus sativus</i>, of Chinese origin belonging to the plant order Capparales. The radish is grown for its thickened hypocotyl, which is eaten uncooked as a salad vegetable (see <b>illus.</b>). Propagation is by seed. Varieties (cultivars) are classified according to root shape and season or time of maturity. Colors include red, yellow, white, black, pink, and red-white combinations. Popular varieties are short-season (21–25 days), Early Scarlet Globe and Comet; medium-season (30–50 days), Crimson Giant; and long-season or winter varieties (50–70 days), Black Spanish. Commercial production, largely of the round red short-season varieties, is primarily in the field but radishes are also produced commercially in greenhouses. Harvesting by hand or machine begins when roots are approximately ½ to 1 in. (13 to 25 mm) in diameter, often only 21–23 days after planting.
Industry:Science
A cool-season annual, <i>Lactuca sativa</i>, of Asian origin and belonging to the tribe Cichorium of the Compositae family. Lettuce is grown for its succulent leaves, which are eaten raw as a salad. Four varieties of this leading salad crop are head lettuce (<i>L. sativa</i> var. <i>capitata</i>; see <b>illus.</b>), leaf or curled lettuce (<i>L. sativa</i> var. <i>longifolia</i>), and stem or asparagus lettuce (<i>L. sativa</i> var. <i>asparagina</i>). There are two types of head lettuce: butterhead, and crisphead or iceberg.
Industry:Science
A cool-season biennial crucifer (<i>Brassica oleracea</i> var. <i>botrytis</i>) of Mediterranean origin. Cauliflower belongs to the plant order Capparales. It is grown for its white head or curd, a tight mass of flower stalks, which terminates the main stem (see <b>illus.</b>). Cauliflower is commonly cooked fresh as a vegetable; to a lesser extent, it is frozen or pickled and consumed as a relish. Cultural practices are similar to those used for cabbage; however, cauliflower is more sensitive to unfavorable environment. Strains of the variety (cultivar) Snowball are most popular; purple-headed varieties are less common. Cauliflower is slightly tolerant of acid soils and has high requirements for boron and molybdenum. A cool, moist climate favors high quality. Harvest is generally 3–4 months after planting. California and New York are important cauliflower-producing states.
Industry:Science
