- 行业: Printing & publishing
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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 black, naturally occurring carbonaceous material having specific gravity 1.10–1.25 and fixed carbon 50–85%. Impsonite is infusible and is insoluble in carbon disulfide. A vein of impsonite 10 ft(3 m) wide occurs in La Flore County, Oklahoma, and there are other deposits in Arkansas, Nevada, Michigan, Peru, Argentina, Brazil, and Australia. The Peruvian impsonite may be derived from grahamite by weathering. The origin of impsonite is not well understood, but it appears to be derived from a fluid bitumen that polymerized after it filled the vein in which it is found. Impsonites are known to contain unusually high percentages of vanadium.
Industry:Science
A black, opaque material that takes a high polish. Jet has been used for many centuries for ornamental purposes. It is a compact variety of lignite coal. It has a refractive index of 1.66 (which accounts for its relatively high luster), a hardness of 3–4 on Mohs scale, and a specific gravity of 1.30–1.35. Jet is compact and durable, and can be carved or even turned on a lathe. The principal source is Whitby, England, where it occurs in hard shales. Although popular from Pliny's day until the nineteenth century, the use of jet for jewelry purposes declined markedly for centuries until a resurgence of interest occurred in the 1960s.
Industry:Science
A blast furnace operated under higher than normal pressure. The pressure is obtained by throttling the off-gas line, which permits a greater volume of air to be passed through the furnace at lower velocity and results in an increasing smelting rate.
Industry:Science
A block of the Earth's crust commonly consisting of crystalline gneisses and schists, the textural appearance of which is generally markedly different from that of the surrounding rocks. Common usage indicates that a massif has limited areal extent and considerable topographic relief. Structurally, a massif may form the core of an anticline or may be a block bounded by faults or even unconformities. In any case, during the final stages of its development a massif acts as a relatively homogeneous tectonic unit which to some extent controls the structures that surround it. Numerous complex internal structures may be present; many of these are not related to its development as a massif but are the mark of previous deformations.
Industry:Science
A block of the Earth's crust, generally with a length much greater than its width, that has been dropped relative to the blocks on either side (see <b>illus.</b>). The size of a graben may vary; it may be only a few inches long or it may be hundreds of miles in length. The faults that separate a graben from the adjacent rocks are inclined from 50–70° toward the downthrown block and have displacements ranging from inches to thousands of feet. The direction of slip on these indicates that they are gravity faults. Graben are found in regions where the crust has undergone extension. They may form in the crests of anticlines or domes, or may be related to broad regional warpings.
Industry:Science
A body of water that separates northeastern Africa from the Arabian Peninsula. The Red Sea forms part of the African Rift System, which also includes the Gulf of Aden and a complex series of continental rifts in East Africa extending as far south as Malawi. The Red Sea extends for 1920 km (1190 mi) from Ras (Cape) Muhammed at the southern tip of the Sinai Peninsula to the Straits of Bab el Mandab at the entrance to the Gulf of Aden. At Sinai the Red Sea splits into the Gulf of Suez, which extends for an additional 300 km (180 mi) along the northwest trend of the Red Sea and the nearly northward-trending Gulf of Aqaba. The 175-km-long (109-mi) Gulf of Aqaba forms the southern end of the Levant transform, a primarily strike-slip fault system extending north into southern Turkey. The Levant transform also includes the Dead Sea and Sea of Galilee and forms the northwestern boundary of the Arabian plate.
Industry:Science
A bolometer element with a positive temperature coefficient of resistance, used to detect and measure power at radio, microwave, infrared, and optical frequencies. The temperature of the barretter increases when electromagnetic energy is absorbed. Barretters are made of metal; therefore, the electrical resistance increases when the temperature increases. The resulting resistance change of the barretter is measured by using direct-current or low-frequency instruments. Early radio demodulators and current regulator tubes using fine iron wires also have been called barretters.
Industry:Science
A book that contains astronomical or meteorological data arranged according to days, weeks, and months of a given year and may also include diverse information of a nonastronomical character. This article is restricted to astronomical and navigational almanacs.
Industry:Science
A borate mineral with chemical composition Mg<sub>3</sub>B<sub>7</sub>O<sub>13</sub>Cl. It occurs in Germany, England, and the United States, usually in bedded sedimentary deposits of anhydrite (CaSO<sub>4</sub>), gypsum (CaSO<sub>4</sub> · 2H<sub>2</sub>O), and halite (NaCl), and in potash deposits of oceanic type. The chemical composition of natural boracites varies, with Fe<sup>2+</sup> or Mn<sup>2+</sup> replacing part of the Mg<sup>2+</sup> to yield ferroan boracite or manganoan boracite.
Industry:Science
A brain disorder that is characterized by unusual mental experiences, such as hallucinations, changes in emotional experience, and severe decrements in social, cognitive, and occupational functioning. The popular belief that schizophrenia is characterized by multiple personalities is a misconception.
Industry:Science
