- 行业: Printing & publishing
- Number of terms: 178089
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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.
The extraction and recovery of metals from their ores by processes in which aqueous solutions play a predominant role. Two distinct processes are involved in hydrometallurgy: putting the metal values in the ore into solution via the operation known as leaching; and recovering the metal values from solution, usually after a suitable solution purification or concentration step, or both. The scope of hydrometallurgy is quite broad and extends beyond the processing of ores to the treatment of metal concentrates, metal scrap and revert materials, and intermediate products in metallurgical processes. Hydrometallurgy enters into the production of practically all nonferrous metals and of metalloids, such as selenium and tellurium.
Industry:Science
The human brain is a bilaterally symmetrical structure which is for the most part richly interconnected by two main bridges of neurons called the corpus callosum and anterior commissure. These structures can be surgically sectioned in humans in an effort to control the spread of epileptic seizures. Although there is no apparent change in everyday behavior of these patients, dramatic differences in cognitive function can be demonstrated under specialized testing conditions. Because of these studies it now can be said that in normal humans these cerebral commissures are largely responsible for behavioral unity; the neural mechanism keeps the left side of the body up to date with the activities of the right side, and vice versa.
Industry:Science
The application of chemical engineering principles to the solution of medical problems due to physiological impairment. Knowledge of organic chemistry is required of all chemical engineers, and many study biochemistry and molecular biology. This training at the molecular level gives chemical engineers a unique advantage over other engineering disciplines in communication with life scientists and clinicians in medicine, since the technical language of modern medicine is based in biochemistry and molecular biology. Practical applications include the development of tissue culture systems, the construction of three-dimensional scaffolds of biodegradable polymers for cell growth in the laboratory, and the design of artificial organs.
Industry:Science
The basic unit of structure and function in nearly all plants. Although plant cells are variously modified in structure and function, they have many common features. The most distinctive feature of all plant cells is the rigid cell wall, which is absent in animal cells. The range of specialization and the character of association of plant cells is very wide. In the simplest plant forms a single cell constitutes a whole organism and carries out all the life functions. In just slightly more complex forms, cells are associated structurally, but each cell appears to carry out the fundamental life functions, although certain ones may be specialized for participation in reproductive processes. In the most advanced plants, cells are associated in functionally specialized tissues, and associated tissues make up organs such as the leaves, stem, and root. Although a substantial body of knowledge exists concerning the features of various types of plant cells, there is a great gap in knowledge of how cells become specialized for particular functions and associations.
Industry:Science
The ability to perceive sound arriving from distant vibrating sources through the environmental medium (such as air, water, or ground). The primary function of hearing is to detect the presence, identity, location, and activity of distant sound sources. Sound detection is accomplished using structures that collect sound from the environment (outer ears), transmit sound efficiently to the inner ears (via middle ears), transform mechanical motion to electrical and chemical processes in the inner ears (hair cells), and then transmit the coded information to various specialized areas within the brain. These processes lead to perception and other behaviors appropriate to sound sources, and probably arose early in vertebrate evolution.
Industry:Science
The common generic name often applied to the genera <i>Andropogon, Dichanthium, Bothriochloa</i>, and <i>Schizachyrium</i> in the grass tribe Andropogoneae. Photosynthesis in this entire tribe follows the C<sub>4</sub> pathway characterized by high activity of the NADP-malic enzyme, providing adaptation to environments with high light intensities and high temperatures during the growing season. The bluestems are medium to tall, warm-season, perennial grasses with basic chromosome numbers of 9 or 10, often exhibiting polyploidy. Although asexual reproduction is common, reproduction is predominantly sexual, and ecotypic variation occurs in wide-ranging species. Prescribed burning is an important management tool, especially in subhumid and humid regions. Because of the bluestems' long season of growth, closely synchronized with decomposition rate, they usually compete successfully against cool-season grasses on soils that are low in fertility. The two most important forage species are big bluestem (<i>A. gerardi</i>) and little bluestem (<i>S. scoparius</i>).
Industry:Science
Sustainable forest management once meant sustained yield, which, according to the Society of American Foresters' <i>Dictionary of Forestry</i>, is “the amount of wood a forest can continuously produce at a given intensity of management.” During the 1990s the scope of sustainable forest management broadened. Instead of viewing the forest as the source of any one economic product (for example, timber, paper, or mushrooms) or service (for example, recreation), sustainable forest management now recognizes the full range of environmental, social, and economic values of the forest. Its mission is to integrate the management of these values so that none are neglected, ensuring that the forest remains both useful and healthy into the future.
Industry:Science
The importance of equipment maintenance in ensuring product quality and plant safety has long been recognized. More recently, industry has begun to understand the impact of maintenance practice on broader elements of manufacturing productivity, such as factory output and product cycle time, as well as on product yield. Rising maintenance costs as a percentage of total operating costs, as well as market pressure to produce competitively priced products, have generated increased awareness and interest in equipment maintenance in industries as diverse as semiconductors and electric utilities. In such equipment-intensive industries, even small improvements in equipment utilization can result in an immediate competitive advantage. Maintenance technology has improved dramatically in the last decade with the development of sophisticated sensors that allow for on-line monitoring of critical process and equipment parameters. At the same time, new operational analysis tools that enable better decision making at the planning and operational stages have become available.
Industry:Science
Spherical or elliptical regions up to 40 micrometers in diameter in which there is a change in color from the surrounding mineral when viewed with a petrographic microscope. Pleochroic halos are found around small inclusions of radioactive minerals—for example, zircon, monazite, allanite, xenotime, and apatite—and in rock-forming minerals, principally quartz, micas, amphiboles, and pyroxenes. Halos have also been identified in coalified wood preserved in deposits on the Colorado Plateau. These small regions of discoloration were recognized by H. Rosenbusch as early as 1873 in cordierite, but it was not until the early twentieth century that J. Joly ascribed pleochroic halos to the effect of irradiation originating from the inclusions.
Industry:Science
The branch of geophysics that studies the processes leading to deformation of planetary mantle and crust and the related earthquakes and volcanism that shape the structure of the Earth and other planets. On the largest scale, these processes are a consequence of the transfer of heat out of planetary interiors due to cooling at their surfaces. Rock contracts as it cools, so that its density increases. The cool surface layer is heavier than the interior and has a tendency to sink into it. At the same time, cooling and solidification of the metallic core heats the deepest portion of the surrounding rocky mantle, causing it to become buoyant. The resulting flow of the mantle causes deformation at the surface. Volcanism arises from the partial melting of hot mantle that rises toward the surface from the deeper interior, in response either to buoyancy or to surface deformation. Surface deformation also results from external loads, such as the distribution of ice and water, tidal loads due to the gravitational attraction of nearby planetary bodies, and meteor impacts.
Industry:Science
