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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 proton combined with a number of water molecules. It is often written as H<sub>3</sub>O<sup>+</sup> and called the hydronium ion. However, this species is best considered as an excess proton on a tetrahedral group of four water molecules and so would be designated as H<sub>9</sub>O<sub>4</sub><sup>+</sup>. For simplicity, it is most commonly written as H<sup>+</sup> (<i>aq</i>).
Industry:Science
A protuberance of the Earth's crustal shell with an area of several million square miles and with sufficient elevation above neighboring depressions (the ocean basins) so that much of it is above sea level.
Industry:Science
A psychiatric disorder in which a dramatic reduction in caloric intake consequent to excessive dieting leads to significant bodily, physiological, biochemical, emotional, psychological, and behavioral disturbances.
Industry:Science
A psychopharmacologic drug that tends to calm overexcited individuals, producing a state of “tranquility.” The term tranquilizer was originally applied to two groups of drugs. Members of one group, the antianxiety drugs, were called minor tranquilizers, and members of the second group, the antipsychotic drugs, were called major tranquilizers. Although drugs in both groups may have a calming effect in appropriate doses, it is now clear that the two groups are quite different.
Industry:Science
A pump that develops its action through the alternate filling and emptying of an enclosed volume.
Industry:Science
A pump that operates on the principle that a force is exerted on a current-carrying conductor in a magnetic field. The high electrical conductivity of the liquid metals pumped (liquid metals are used as the heat-transfer media in some nuclear reactors and magnetohydrodynamic systems) allows a pumping force to be developed within the metals when they are confined in a duct or channel and subjected to a magnetic field and to an electric current. These pumps are designed principally for use in liquid-metal-cooled reactor plants where liquid lithium, sodium, potassium, or sodium-potassium alloys are pumped. Other metallic and nonmetallic liquids of sufficiently high electrical conductivity, such as mercury or molten aluminum, lead, and bismuth, may also be pumped in nonnuclear applications. The absence of moving parts within the pumped liquid eliminates the need for seals and bearings that are found in conventional mechanical pumps, thus minimizing leaks, maintenance, and repairs, and improving reliability. In liquid-metal-cooled nuclear reactor plants, electromagnetic pumps with a capacity of up to several thousand gallons per minute have operated without maintenance for decades.
Industry:Science
A pyroclastic rock deposit formed by one or more ground-hugging flows of hot volcanic fragments and particles, essentially synonymous with pyroclastic-flow deposit, ash-flow tuff, flood tuff, or welded tuff. When coined by the New Zealand geologist P. Marshall in 1935, the term “ignimbrite” referred only to flows with emplacement temperatures high enough to cause the fragments forming the deposit to become adhered together or welded; this restriction no longer applies, and the term now includes any pyroclastic-flow deposit, welded or not.
Industry:Science
A pyroxene close in composition to magnesium metasilicate (MgSiO<sub>3</sub>). Like other pyroxenes, enstatite is typified by a pair of nearly perpendicular cleavages, both of which are parallel to the elongate dimension of the characteristically prismatic crystals. These cleavages reflect an atomic structure dominated by unbroken, parallel, linear chains of SiO<sub>4</sub> tetrahedra (silicon atoms surrounded by four oxygens).
Industry:Science
A quantitative analytical process that is basically volumetric. However, in high-precision titrimetry the titrant solution is sometimes delivered from a weight buret, so that the volumetric aspect is indirect. Generally, a standard solution, that is, one containing a known concentration of substance X (titrant), is progressively added to a measured volume of a solution of a substance Y (titrand) that will react with the titrant. The addition is continued until the end point is reached. Ideally, this is the same as the equivalence point, at which an excess of neither X nor Y remains. If the stoichiometry or exact ratio in which X and Y react is known, it is possible to calculate the amount of Y in the unknown solution.
Industry:Science
A quantitative measure of a star's color. Even a casual look at the night sky reveals the stars to be colored. From spectral analysis and the laws of radiation, it has been known since the 1920s that such color is closely related to temperature. Stars are reddish at about 3000 K (4940°F), orange at about 4500 K (7640°F), yellowish-white at about 6000 K (10,340°F), white at about 10,000 K (17,540°F), and bluish-white above 10,000 K. With proper calibration, color provides a means by which the temperature and spectral class can be evaluated. Visual examination is too crude, however. Instead, color must be properly defined and quantified.
Industry:Science
