bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cadmium Compounds
Authors: Herron Norman 
Published: August 2004

Abstract

Naturally occurring cadmium compounds are limited to the rare minerals, greenockite, CdS, and otavite, an oxycarbonate, but neither is an economically important source of cadmium metal or its compounds. Instead, cadmium compounds are usually derived from metallic cadmium produced as a by‐product of lead‐zinc smelting or electrolysis. In general, cadmium compounds exhibit properties similar to the corresponding zinc compounds. The principal areas of cadmium usage in terms of U.S. consumption in 1990 were batteries, 50%; pigments, 20%; plastic stabilizers, 15%; metal finishing, 10%; electronics and optics,

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; and catalysts,

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. Cadmium hydroxide is the anode material of Ag–Cd and Ni–Cd rechargeable storage batteries. Cadmium sulfide, selenide, and especially telluride find utility in solar cells. In flexible PVC, cadmium salts such as stearate are used as heat and light stabilizers. Cadmium cyanide, acetate, fluoroborate, or sulfate is used as an electrolyte in electroplating onto other metals, imparting corrosion protection. The cadmium chalcogenide semiconductors have found numerous applications ranging from rectifiers to photoconductive detectors in smoke alarms. Many Cd compounds are used as phosphors in luminescent screens. Demand for cadmium and its compounds in the United States has generally declined after peaking during the late 1970s. The declining use of cadmium in plastics and as pigments in the 1980s, largely because of health and environmental concerns and the concomitant introduction of Cd substitutes, has been offset by its increased use in rechargeable storage (Ni–Cd) batteries. Continued and growing concern over the toxicity of cadmium in the environment is expected to lead to alternatives for cadmium compounds in all applications. Inorganic compounds include cadmium arsenides, antimonides, and phosphides; cadmium borates; cadmium carbonate; cadmium complexes; cadmium halides; cadmium hydroxide; cadmium nitrate; cadmium oxide; cadmium phosphates; and others. Many organocadmium compounds are known but few have been of commercial importance. They include dialkyl cadmium compounds, cadmium acetate, and organocadmium soaps.
Aluminum Oxide (Alumina), Calcined, Tabular, and Aluminate Cements
Authors: MacZura George 
Published: August 2004

AbstractCalcined aluminas are generally obtained from Bayer process gibbsite α‐Al(OH)3, thermal decomposition of which follows the transition through the generic gamma alumina phases to α‐alumina (corundum), α‐Al2O3. Calcination of gibbsite has been done in rotary kilns for many years. Specialty calcined aluminas can also be prepared in stationary or fluid bed calciners. Most ceramic grade aluminas are supplied dry ground to about 95%\documentclass{article}\pagestyle{empty}\begin{document}${{\rm{-}}325{\hskip0.167em}{\hskip0.167em}{\rm{mesh}}}$\end{document}(44 µm) using 85–90% Al2O3ceramic ball, attrition, vibro‐energy, or fluid‐energy milling. More fully ground, or superground, calcined aluminas having particle size distributions that approximate the natural or ultimate crystal size of the Bayer grain as calcined are often desired. Thermally reactive aluminas contain submicrometer crystals. These must be separated from the Bayer agglomerate during grinding to permit dense compaction upon ceramic forming, and thus, enhance densification upon sintering at lower temperatures. Process control techniques permit production of calcined specialty aluminas having controlled median particle sizes differentiated by about 0.5 µm. This broad selection enables closer shrinkage control of high tech ceramic parts. Tabular alumina is a high density, high strength form of α‐Al2O3made by sintering an agglomerated shape of ground, calcined alumina. It is available in the form of smooth balls which are crushed, screened, and ground to obtain a wide variety of graded, granular, and powdered products. Tabular alumina is the ideal base material for high alumina brick, and monolith liners in the metal, ceramic, and petrochemical industries. Other applications include their use in electrical insulators, electronic components, and kiln furniture. High purity calcium aluminate cements (CAC) are primarily used as binders for high strength refractory castables to form linings up to about 1.0 m thick, as in iron blast furnaces. The high purity CAC finds extensive use as an efficient binder for other aggregates such as fire clays, kaolin, andalusite, kyanite, pyrophyllite, sillimanite, mullite, and refractory‐grade bauxite. The many applications cited for tabular alumina in refractories are also common for high purity CAC.
Calcium Sulfate
Authors: Petersen Donald J. , Kaleta Norbert W. , Kingston Larry W. 
Published: August 2004

AbstractCalcium sulfate, CaSO4, in mineral form is commonly called and occurs abundantly in many areas of the world. In natural deposits, the main form is the dihydrate. Some anhydrite is also present in most areas, although to a lesser extent. The hemihydrate is normally produced by heat conversion of the dihydrate. The resulting powder is also known as plaster of Paris. Stucco has the greatest commercial significance of these materials. It is the primary constituent used to fabricate products and in formulated plasters used in job or shop‐site applications. About\documentclass{article}\usepackage{amssymb}\pagestyle{empty}\begin{document}${23\times 10^{6}{\hskip0.167em}{\hskip0.167em}{\rm{t}}}$\end{document}of gypsum are consumed annually. About 80% is processed into the commercially usable hemihydrate. Uses of gypsum are in fabricated or formulated building materials, Portland cement set regulation, and agricultural soil conditioning. The natural, or mineral, form of gypsum is most widely extracted by mining or quarrying and used commercially. Gypsum is also obtained as a by‐product of various chemical processes. The main sources are from processes involving scrubbing gases evolved in burning fuels that contain sulfur, and the chemical synthesis of chemicals, such as sulfuric acid, phosphoric acid, titanium dioxide, citric acid, and organic polymers. Gypsum rock from the mine or quarry is crushed and sized to meet the requirements of future processing or removed for direct marketing of the dihydrate as a cement retarder. Once subjected to a secondary crusher, calcining, and drying, the product is fine‐ground. The majority of fine‐ground dihydrate is used as feed to calcination processes for conversion to hemihydrate. The dehydration of gypsum, commonly referred to as calcination in the gypsum industry, is used to prepare hemihydrate, or anhydrite. Three processing methods are used for the production of α‐hemihydrate. One involves charging lump gypsum rock into a vertical retort and applying steam. After calcination for 5–7 h the hot moist rock is quickly dried and pulverized. Another method has lower water demand. The dihydrate is heated in a water solution containing a metallic salt at pressures not exceeding atmospheric. A third method prepares very low water‐demand α‐hemihydrate by auto‐claving powdered gypsum in a slurry. A crystal‐modifying substance is added to produce large squat crystals. Soluble anhydrite is commercially manufactured in a variety of forms by low temperature dehydration of gypsum. Crude gypsum is the principal form of calcium sulfate shipped in international trade, although by the 1980s an increased volume of fabricated products moved across international borders.
Carbon Disulfide
Authors: Smith David E. , Timmerman Robert W. 
Published: August 2004

AbstractCarbon disulfide, CS2, is a highly volatile, flammable, clear, colorless, dense liquid that has many useful chemical and physical properties. An industrially important chemical for over one hundred years, most carbon disulfide is now produced by reaction of hydrocarbon gas with sulfur in a process developed in the 1950s, although many small capacity plants still employ a retort or electric furnace route based on wood charcoal and sulfur. Modern plants achieve a 99.99% pure carbon disulfide product by means of fractional distillation. Over 75% of the estimated one million tons of carbon disulfide produced worldwide in 1991 went into manufacturing viscose rayon and cellophane film. Carbon disulfide is also used in manufacturing numerous organic sulfur compounds for a variety of applications including rubber vulcanization accelerators, flotation chemicals, pharmaceutical intermediates, fungicides, and insecticides. The carbon disulfide process route to carbon tetrachloride was discontinued in the United States during 1991 because of environment pressures on the end product. Carbon disulfide is very toxic, and the U.S. Government limits the 8‐h time‐weighted average exposure to 4 ppm maximum (12 mg/m3) in air. Health and environmental concerns related to carbon disulfide have curtailed some uses, such as in grain fumigants and solvents. Special precautions must be exercised in handling carbon disulfide because of its toxicity, high volatility, wide flammability range, and low ignition temperature.
Cardiovascular Agents
Authors: Cervoni Peter , Crandall David L. , Chan Peter S. 
Published: August 2004

AbstractThe six primary classes of cardiovascular drugs, ie, antiarrhythmic agents, antianginal agents, agents used in the treatment of congestive heart failure, antiatherosclerotic agents, antihypertensive agents, and thrombolytic agents, are reviewed. An overview of the physiology of the cardiovascular system is presented for each class together with the pathology of the system leading to specific cardiovascular disorders. The mechanism(s) of action of the cardiovascular agents are discussed when known, and the principal actions of the cardiovascular agents that contribute to amelioration of the underlying pathology of the cardiovascular disease are reviewed. Side effects and toxicities of the cardiovascular agents are also presented. Drugs clinically in use and some of those drugs under development are discussed. A brief review of the current and projected sales of ethical pharmaceuticals is presented in relation to the sales of cardiovascular agents which is the fastest growing segment of the ethical pharmaceutical market.
Catalysis
Authors: Gates Bruce C. 
Published: August 2004

AbstractCatalysis is the key to efficient chemical processing. Catalysts increase the rates of chemical reactions without affecting the equilibrium and, ideally, without being consumed. Catalysts work by forming chemical bonds with reactants and providing energetically favorable pathways for their conversion into products. This article is a summary of catalysis in solutions and on surfaces, including basic definitions and principles and numerous industrial examples; it is organized to emphasize the unity of the subject, direct the reader to the literature, and provide practical guidelines about technological applications.
Separation, Centrifugal Separation
Authors: Letki Alan , Moll R. T. , Shapiro Leonard 
Published: August 2004

AbstractSeparation by density difference and drainage is presented, along with formulas developed for bottle, solid wall, and disk centrifuges. The Σ‐concept is developed and several practical variants are discussed. Liquid–liquid separation interface location formulas are reviewed. Centrifuge components, including a breakdown of power and energy losses with applicable information for centrifuges, are represented. Centrifuge materials of construction and their corrosion, erosion, and strength characteristics are reviewed. Stresses generated owing to rotation and material and process fluids, abrasion resistance, and noise generated by centrifuges are discussed. The various types of sedimentation and filtration equipment are reviewed. Examples of use, rates, and performance of bottle; disk; continuous conveyor discharge; preparation; zonal; tubular; perforate basket; inverting filter; conical; and continuous single‐ and multiple‐stage pusher centrifuges are reviewed. Gas centrifuges and their use in uranium enrichment are presented.
Ceramics As Electrical Materials
Authors: Buchanan R. C. , Roseman R. D. 
Published: August 2004

Abstract
There are a large number of applications for ceramic materials where electrical conduction properties are important. These materials exhibit a wide range of conductivities from highly insulating to highly conducting. Other electrical properties, associated with magnetic and dielectric polarization, superconduction, and environmental sensing functions, may also be present. Ceramic properties are developed through composition selection combined with highly specific firing or heat treatment processes, where the base compositions and dopants interact to give complex materials having engineered micro and defect structures. Many of the developed ceramics are an integral part of modern microcircuit technology, in which advantage is taken not only of the high resistivity and range of dielectric behavior, but of the semiconducting and low resistivity properties. The development of electronic components, such as highly complex sensors and actuators, superconductors, multilayer and miniaturized microelectronic devices, and insulation applications for high frequency, temperature, voltage, and stressed components, have been made possible through the use of these ceramics. The conduction phenomena and mechanisms that control electrical behavior in each type of material is discussed.
Chelating Agents
Authors: Howard William L. , Wilson David A. 
Published: August 2004

AbstractChelating agents or chelants are compounds having two or more donor atoms that can form cyclic coordination complexes or chelates with acceptor metals. The complexation is an equilibrium reaction which often strongly favors the complex. Chelating is used to modify or control the behavior of metals and their compounds by controlling the concentration of the metals in solution or to utilize the special properties of the chelation compounds. The active groups in chelants may be linear chains, eg, ‐N‐C‐C‐N‐, macrocyclic rings, eg [‐O‐C‐C]n, or polycyclic structures, such as the cryptates, eg, X[‐C‐C‐Y‐C‐C)n]3Y where X and Y are bridgehead and donor atoms, respectively. Some pH, stability, solubility, and electrochemical relationships among simultaneous equilibria in chelation are shown. A broad range of applications based on concentration control, the special properties, and medical uses of chelation compounds are given. Metal sequestration, solubilization, and buffering are discussed as are metal extraction, precipitation, and displacement. Economic data for industrial chelating agents are given. Use of chelating agents is essentially benign environmentally and presents little or no hazard to health or safety under normal conditions of use and handling.
Chemicals In War
Authors: Harris B. L. 
Published: August 2004

AbstractChemicals used in war fit into five categories: flame agents, incendiaries, smokes and obscurants, incapacitants and riot control agents, and toxic agents. Flame agents, typically hydrocarbons or other readily flammable liquids, are used in flame throwers and flame projectors such as flame rockets. Incendiaries are often metals such as magnesium or aluminum, or oil and metal mixtures. These materials often require a fuse or ignition cup. Smokes and obscurants may be gaseous, liquid, or particulate aerosols. Incapacitants and riot control agents are designed to incapacitate but not permanently damage. These substances may be atropinemetics, or lacrimators, sternutators, vesicants, or urticants. Effects of atropinemetics may last from a few hours to a few days; effects of the latter materials usually dissipate within minutes upon removal from the agent. The toxic agents are generally of two types, vesicants such as the sulfur or nitrogen mustard gases, or the organophosphate nerve agents.Defense against toxic agents requires agent detection and identification; individual and collective protection of personnel and equipment; decontamination materials and procedures; and medical defense.
Chlorine Oxygen Acids and Salts, Chloric Acid and Chlorates
Authors: Mendiratta Sudhir K. , Duncan Budd L. 
Published: August 2004

AbstractSodium chlorate is the primary raw material for the manufacture of chlorine dioxide, a bleaching agent in the pulp and paper industry. Increases in the chlorine dioxide substitution for chlorine in pulp bleaching have resulted in an average growth of 12%/y in production. Sodium chlorate is prepared electrolytically. The modern technology described minimizes sodium chloride and sodium dichromate impurities. Chlorates are powerful oxidizers, and they are also used in perchloric salt and uranium production.Chloric acid technologies have been developed which allow the generation of chlorine dioxide directly from the acid, without the formation of sodium salts in the generator.
Chloramines and Bromamines
Authors: Wojtowicz John A. 
Published: August 2004

AbstractN‐Halamines are inorganic and organic compounds in which halogen is attached to nitrogen. They have both research and commercial importance. TheN‐halogen bond is formed by reaction of an amine, imine, amide, or imide with halogen, hypohalous acid, or hypochlorite. Only the chloro and bromo derivatives are of commercial importance. The physical and chemical properties, preparation, manufacture, uses, safety and handling, toxicity, and economic aspects of chloramines and bromamines are discussed. The chemistry of chloramines and bromamines is diversified not only because nitrogen and halogen act as reaction sites but because of the different modes by which these functionalities react. Research activity on synthetic applications of chloramines and bromamines continues to be high.In aqueous solution, these chloramines and bromamines undergo hydrolysis to varying degrees forming hypochlorous and hypobromous acids. Thus theseN‐halamines can be considered as halogen release agents and many, eg, chloroisocyanurates, find use in bleaching, disinfecting, and sanitizing applications. Others, such as halogen derivatives of ammonia, are important because they are industrial process intermediates (monochloramine) or of significance in water treatment (mono‐, di‐, and trichloramine).
Chromium and Chromium Alloys
Authors: Westbrook Jack H. 
Published: August 2004

Abstract
Chromium metal, chromium alloys, and metallurgically important chromium compounds are reviewed. Occurrence, mining, and smelting of chromium ores are discussed. The chemical, physical, and mechanical properties of chromium metal are summarized. Important Cr‐bearing alloys: the various stainless steels, alloy steels, nonferrous alloys, and Cr‐based alloys are identified as are metallurgically important compounds. Applications of these materials are discussed and the contribution of chromium to the properties of these alloys is described. Methods of producing Cr‐rich protective and decorative surfaces, recovery and reuse of Cr‐bearing materials, and toxicology are reviewed.
Coal
Authors: Vorres Karl S. 
Published: August 2004

AbstractCoal.Coal, mined throughout the world, is used primarily for electric power generation in the United States either as the solitary fuel or in cogeneration systems. Steelmaking is the second largest usage for coal. The constituent original plant parts can be identified microscopically and coal is classified according to heating value, fixed carbon, and coking properties. Classes of coal range from the hard anthracite to the soft subbituminous materials and lignite. Sulfur in coal may be in both organic and inorganic constituents. The inorganic sulfur is more easily removed. Coal properties are tied to composition and to structure.Synthetic crude oil can be produced from coal by hydrogenation, and transportation fuels by indirect liquefaction or gasification. Gasifiers are used to make chemical intermediates and to produce electric power by integrated gasification combined cycle systems. Coal cleaning is important to meeting environmental regulations. Coal reserves in the United States can sustain U.S. demand for over 100 years.
Cobalt and Cobalt Alloys
Authors: Hodge F. Galen 
Published: August 2004

AbstractCobalt is a metallic element the earliest uses of which were as colorants for glass and pottery. Cobalt has unique magnetic properties. The largest consumption of cobalt is in the metallic form as magnetic alloys, cutting and wear‐resistant alloys, and high temperature superalloys. The second largest use of cobalt is in the form of salts, including lacquers, enamels, colorants for glass, and catalysts. Radioactive cobalt has considerable application in radiochemistry and radiography.Cobalt‐base alloys are generally described as wear‐resistant, corrosion‐resistant, and heat‐resistant. Many of the properties of the alloys arise from the crystallographic nature of cobalt, the solid solution strengthening effects of chromium, tungsten, and molybdenum, the formation of carbides, and the corrosion resistance imparted by chromium.
Cobalt Compounds
Authors: Richardson H. Wayne 
Published: August 2004

AbstractAn overview of cobalt compounds including the chemistry exhibited by the +2 and +3 valences is presented emphasizing those compounds of industrial significance. Methods of manufacture for many of the commercial compounds are given as is transition‐metal separation methodology. The biological role of cobalt in humans and ruminants is discussed.The primary use of cobalt compounds is in catalysis for hydrotreating petroleum resulting in hydrodesulfurization. Cobalt catalysts are also used to denitrify, deoxgenate, crack crude oil and gas, and in homogeneous oxidation and the oxo process (hydroformylation). Cobalt compounds are used in pigments for paints and priting iks, as colorants for glass, ceramics, and enamels, and in the form of metallic soaps as driers. Less significant industrial uses are in electronics, agriculture as feed and soil additives, and as an adhesive in the tire industry.
Color Photography
Authors: Kapecki Jon , Rodgers James 
Published: August 2004

AbstractColor photography is the technology by which the visual appearance of a three‐dimensional subject may be reproduced on a two‐dimensional surface having a pleasing balance of brightness, hue, and color. Light capture is primarily effected by silver halide crystals. Integral tri‐color film packs also contain spectral sensitizing dyes and colored masking couplers appropriate to the subtractive primary dyes, filters, and an overcoat.The chromogenic chemistry of the color photography process involves the reactions ofp‐phenylenediamine developers and various couplers. Prototype dye couplers, which often contain an organic ballast to enhance solubility in hydrophobic solvents, colored masking couplers, and development‐inhibitor‐releasing couplers, which carry a silver development inhibitor linked to the film coupling site, are given. Both chromogenic and post‐development film chemistries are described as are the relationships between film speed, light sensitivity, dye stability, image structure, and color reproduction.