bluuebunny/crossref_metadata_2025_split huggingface dataset:
Butylenes
Authors: Calamur Narasimhan , Carrera Martin E. , Wilsak Richard A. 
Published: July 2004

AbstractButylenes are C4H8mono‐olefin isomers: 1‐butene,cis‐2‐butene,trans‐2‐butene, and isobutylene (2‐methylpropene). These isomers are usually coproduced as a mixture and are commonly referred to as the C‐4 fraction. These C‐4 fractions are usually obtained as by‐products from petroleum refinery and petrochemical complexes that crack petroleum fractions and natural gas liquids. Since the C‐4 fractions almost always contain butanes, it is also known as the B–B stream. The linear isomers are referred to as butenes. The carbon–carbon double bond is the distinguishing feature of the butylenes and, as such, controls their chemistry. The carbon–carbon bond, acting as a substitute, affects the reactivity of the carbon atoms at the alpha positions through the formation of the allylic resonance structure. This structure can stabilize both positive and negative charges. Reactions of butylenes can be divided into two broad categories: those that take place at the double bond itself, destroying the double bond; and those that take place at alpha carbons. The C‐4 isomers are almost always produced commercially as by‐products in a petroleum refiner–petrochemical process. There are other commercial processes available for the production of butylenes. However, these are site‐ or manufacturer‐specific. Any of these processes can become an important source in the future. Several technologies are emerging for the production of isobutylene to meet the expected demand for isobutylene: deep catalytic cracking; superflex catalytic cracking; dehydrogenation of butanes; and the Coastal process of thermal dehydrogenation of butanes. There are four types of separation methods available: selective removal of isobutylene by polymerization and separation of 1‐butene; use of addition reactions with alcohol, acids, or water to selectively produce pure isobutylene and 1‐butene; selective extraction of isobutylene with a liquid solvent, usually an acid; and physical separation of isobutylene from 1‐butene by absorbents. There are three important processes for the production of isobutylene; the extraction process using an acid to separate isobutylene; the dehydration oftert‐butyl alcohol, formed in the Oxirane process; and the cracking of MTBE. Handling requirements are similar to liquefied petroleum gas (LPG). Butylenes are not toxic. The effect of long‐term exposure is not known; hence, they should be handled with care. They are volatile and asphyxiants. Care should be taken to avoid spills because they are extremely flammable.
Butyl Rubber
Authors: Webb Robert N. , Shaffer Timothy D. , Tsou Addy H. 
Published: July 2004

Abstract

Butyl rubber and other isobutylene polymers in wide use include various homopolymers and copolymers. Low levels of unsaturation for subsequent cross‐linking are incorporated by copolymerization with isoprene. Halogenation at the unsaturation site provides additional cross‐linking mechanisms and covulcanization with highly unsaturated elastomers. Polymers containing star branches, conjugated‐diene sites, divinylbenzene, and brominated
p
‐methylstyrene have also been synthesized. Isobutylene polymers are polymerized by a cationic mechanism, using a Brønsted acid as an initiator and a Lewis acid as a coinitiator, eg, water and aluminum chloride. Molecular weights range from several hundred for terminally unsaturated polybutenes to over a million for elastomer grades.

The
T
g
of polyisobutylene is about −70°C, and the polymer is amorphous in the unstrained state. The polymers exhibit a broad damping peak and a low plateau modulus. They display an exceptionally low permeability to gases, and are widely used as air retention barriers in tires. Optimum physical properties are obtained by compounding with carbon black and other fillers. Various mechanisms are used to cross‐link the compounds into elastomeric vulcanizates. Sulfur is used to provide polysulfidic cross‐links, while resin and zinc oxide cure systems give carbon–carbon cross‐links. Besides inner tubes and innerliners, butyl rubbers are used in blends to improve cut‐growth resistance and wet‐skid resistance. Blends with thermoplastic resins improve toughness. Polyisobutylenes enjoy extensive use as adhesives and caulks, and are chemically modified for use in lubricants as dispersants.
Calcium Carbonate
Authors: Carr F. Patrick , Frederick David K. 
Published: July 2004

Abstract

Calcium carbonate, CaCO
3
, occurs naturally as the principal constituent of limestone, marble, and chalk. Powdered calcium carbonate is produced by two methods on the industrial scale. It is quarried and ground from naturally occurring deposits and in some cases beneficiated. It is also made by precipitation from dissolved calcium hydroxide and carbon dioxide. The natural ground calcium carbonate and the precipitated material compete industrially based primarily on particle size and the characteristics imparted to a product. Calcium carbonate is one of the most versatile mineral fillers and is consumed in a wide range of products, including paper, paint, plastics, rubber, textiles, caulks, sealants, and printing inks. High purity grades of both natural and precipitated calcium carbonate meet the requirements of the
Food Chemicals Codex
and the
United States Pharmacopeia
and are used in dentifrices, cosmetics, foods, and pharmaceuticals. Calcium carbonate occurs naturally in three crystal structures: calcite, aragonite, and, although rarely, vaterite. The commercial grades of calcium carbonate from natural sources are either calcite, aragonite, or sedimentary chalk. In most precipitated grades aragonite is the predominant crystal structure. Calcium carbonate is listed as a food additive and not considered a toxic material. The exposure to dust is regulated, and both natural ground and precipitated calcium carbonates can contain low levels of impurities that are regulated.
Fluorine Compounds, Inorganic, Calcium
Authors: Vrana Lisa M. 
Published: July 2004

AbstractCalcium fluoride, commonly called fluorspar or fluorite, is the principal fluoride‐containing mineral. Whereas there are some domestic U.S. sources, much of the fluorspar used in the United States is imported. Fluorspar is marketed in several grades: metallurgical fluorspar sold as gravel, lump, or briquettes; ceramic‐grade fluorspar; and acid‐grade fluorspar. The latter is used in the open‐hearth process for the production of steel as well as to produce hydrogen fluoride.
Calcium Sulfate
Authors: Lancia Amedeo , Musmarra Dino , Prisciandaro Marina 
Published: July 2004

AbstractCalcium sulfate, CaSO4, has several forms, ie, calcium sulfate dihydrate (commercially known as gypsum), calcium sulfate anhydrous (anhydrite), calcium sulfate hemihydrate, present in two different structures, α‐hemihydrate and β‐hemihydrate (commercial name of β‐form: stucco or plaster of Paris). It is found abundantly in many area of the world, where it is extracted by mining or quarrying and recently was obtained as a by‐product by numerous industrial applications. In natural deposits, the main form is the dihydrate, some hemihydrate is also present in most areas, although to a lesser extent. 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 (FGD gypsum), and the chemical synthesis of chemicals, such as sulfuric acid, phosphoric acid, titanium dioxide, citric acid, and organic polymers. The hemihydrate is normally produced by heat conversion of the dihydrate. Stucco is the primary constituent used to fabricate products and in formulated plasters used in job or shop‐site applications. About 20–25 million metric tons of calcium sulfate are consumed annually. About 20% of it, in the dihydrate form, is used in fabricated or formulated building materials, Portland cement set regulation, and agricultural soil conditioning, while ∼80% is processed into the commercially usable hemihydrate. The dehydration of gypsum, commonly referred to as calcination in the gypsum industry, is used to prepare hemihydrate, or anhydrite. In addition, calcium sulfate precipitation is relevant in scaling problems, where gypsum formation is an unwanted occurrence, such as in water desalination, industrial water recovery in cooling tower technology, water distillation, and phosphoric acid production.
Sugar, Cane Sugar
Authors: Clarke Margaret A. 
Published: July 2004

AbstractThis article outlines the history of sugarcane as a source of sucrose sweetener, and traces the development of major industrial unit processes for sugar production. Chemical and physical properties of sucrose, specifically of cane sugar, are listed. Cultivation and harvest of sugarcane and product of either raw cane sugar or direct consumption (plantation white) cane sugar are described. Production of noncentrifugal cane sugar is described briefly. Yields and production statistics for recent years are given, and production figures are listed throughout. Processes for refining raw sugar into refined white and brown products are delineated, and the products and their standards are described. Other products from cane sugar and sugarcane are described.
Carbon Black
Authors: Wang Meng‐Jiao , Gray Charles A. , Reznek Steve A. , Mahmud Khaled , Kutsovsky Yakov 
Published: July 2004

AbstractCarbon black is a generic term for an important family of products used widely to modify the mechanical, electrical, and other physical properties of the medium in which it is dispersed. It is the most widely used nanomaterial, with particle dimensions ranging from tens to a few hundred nanometers (nms). It plays a major role in elastomers, plastics, paints and inks as a reinforcing agent, a black pigment, and an electrically conductive material. This article provides a comprehensive review of the technical and commercial aspects of carbon black usage. The history of carbon black, its microstructure, chemical composition, morphology, surface activity, and characterization are discussed. The mechanism of carbon black formation and its manufacture, including oil‐furnace black process, thermal black process, acetylene black process, lampblack process, and impingement black process, is described. A separate section is included on newly developed surface modification technologies and related commercial applications. One section is devoted to the properties, applications and markets of the two main types of carbon blacks, rubber grades and special grades. The rubber grades are primarily used as a reinforcing agent in tire and other rubber products to improve their mechanical properties. Most of the special grades are manufactured to meet specific product specifications for imparting certain properties required by the end use products, such as dispersion, pigmentation and electrical conductivity. The health, safety, and environmental section includes a summary of recent health studies.
Carbonated Beverages
Authors: Morrow R. Steve , Quinn Christine M. 
Published: July 2004

Abstract

Carbonated beverages were first introduced in the late 1880s. The annual per capita consumption of soft drinks in the United States has steadily risen from 16 oz (

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) in 1860 to nearly 48 gallons (

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) today.

The ingredients used to produce soft drinks include water, nutritive or nonnutritive sweeteners, acidulants, preservatives, carbon dioxide, colorants, and flavoring ingredients. Manufacturing of soft drinks generally includes preparing syrup from ingredients and then mixing with carbon dioxide and water. Quality control programs for ingredients, syrups, beverages, and packaging materials are conducted to ensure the integrity of the beverage.
Beverages are packaged in steel or aluminum cans, returnable and nonreturnable glass, and plastic bottles. Recycling and source reduction are important issues to the soft drink industry. New packaging utilizing recycled materials, market growth, and development of new nonnutritive sweeteners are important areas for future development.
Carbon and Graphite Fibers
Authors: Venner Joseph G. 
Published: July 2004

AbstractCarbon and graphite fibers have rapidly emerged as a primary reinforcement in composite applications requiring high specific stiffness and strength. These fibers are manufactured from the thermal conversion of polyacrylonitrile, pitch, or rayon precursors. The modulus and strength of carbon fibers can be adjusted through control of process conditions resulting in a family of carbon fiber products classified as low modulus (LM), standard, intermediate modulus (IM), high modulus (HM), and ultrahigh modulus (UHM) carbon fiber. Primary process steps including precursor formation, stabilization, carbonization, surface treatment, and sizing are described. Basic interrelationships between fiber structure, fiber properties, and process conditions are reviewed. Brief overviews of quality control approaches, safety and health considerations for handling carbon fiber, applications, and market growth are also included.
Metal Carbonyls
Authors: McIndoe J. Scott , Dyson Paul J. 
Published: July 2004

AbstractCarbon monoxide forms a host of metal carbonyl complexes, at least one for every transition metal. Mononuclear, polynuclear, and heteronuclear metal carbonyls are all known. The complexes, of general formula Mx(CO)y, may be charged or neutral; the metal or metals are in low, zero, or negative oxidation states. Synthesis of the metal carbonyls usually proceeds either from the reduction of the corresponding metal salt, although direct reaction between the metal and CO takes place for certain elements. Clusters are usually made via condensation of lower molecular weight compounds. The structure and bonding of the metal carbonyls, including those of cluster compounds, follow well‐defined rules. Metal carbonyls are extremely useful as reagents in organic synthesis and catalysts, playing a pivotal role in both the Reppe and the oxo processes, as well as in the preparation of fine chemicals.
Copper Alloys, Cast Copper Alloys
Authors: Twarog Daniel L. 
Published: July 2004

Abstract
Cast copper alloys are used for their generally superior corrosion resistance, high electrical and thermal conductivities, and good bearing and wear qualities. These alloys are identified by Unified Numbering System designation. Irregular and complex external and internal shapes can be produced by various casting methods at less overall cost than by other means. The commonly used casting methods are compared, and casting characteristics of both single and polyphase alloys are described.
Cast copper alloys include both yellow and red brasses as well as semired brasses and many bronzes. Alloy composition, on which the alloy properties depend, and usage are given.
Initiators, Cationic
Authors: Faust Rudolf 
Published: July 2004

AbstractCationic initiation in general and the cation donor (initiator)/Friedel‐Crafts acid (coinitiator) initiating system in particular are reviewed. The efficiency of a particular initiating system depends on the reactivity of the initiating cation relative to that of the propagating center. The strength of the Friedel‐Crafts acid and the nucleophilicity of the formed counteranion also affect the rates of initiation and propagation as well as the influence of solvent polarity. Controlled initiation in the absence of chain transfer, the inifer technique, and living cationic polymerization systems are reviewed. These systems have resulted in head group control, molecular weight, and end group control, and in the synthesis of well‐defined materials with controlled architecture, molecular weight, molecular weight distributions, and end functionalities.
Cell Culture Technology
Authors: Karkare Subhash B. 
Published: July 2004

Abstract

Cell culture technology refers to the
in vitro
processes employed for the growth of mammalian, insect, or plant cells to manufacture biochemicals of commercial importance. Cell culture products, typically therapeutics or medical diagnostics, are regulated by the FDA. The market for cell culture‐derived products is growing and is expected to continue to grow into the twenty‐first century.The technology involved in cell growth is often dependent on cell line type. Hybridoma cells, used for the production of monoclonal antibodies, can be grown in suspension cultures in a manner similar to that used in microbial fermentation. Other cell systems require microcarriers or supports. All of these cells have higher shear sensitivity than microbial cells. Both batch and continuous processes, cell growth kinetics, cell aeration, growth media, product isolation, and purification are discussed, as are safety regulations and standards.
Fibers, Cellulose Esters
Authors: Serad George A. 
Published: July 2004

AbstractThe principal cellulose ester fiber is cellulose acetate, a partially acetylated cellulose, also called acetate or secondary acetate. Although widely used in textiles, its primary use is now for the preparation of cigarette filters, which consumed 65% of the 731,000 metric tons produced worldwide in 1991. Cellulose triacetate is an almost totally acetylated cellulose, but environmental considerations encountered in the preparation of fibers have almost totally eliminated its production.This article initially describes the physical and chemical properties of cellulose acetate and triacetate polymers and fibers. A review of the manufacturing process operations and considerations follows, providing an overview of the key process steps. Since both textile and cigarette filter applications are commercially important, both are described to illustrate the products available and how they are used. Finally, a brief overview of some smaller volume applications provides some insight into other possible uses.
Cement
Authors: Kosmatka Steven 
Published: July 2004

Abstract
Inorganic hydraulic cements, upon reaction with water, form relatively insoluble, bonded aggregations having considerable strength and dimensional stability. The cement produced in the greatest volume is portland cement, which is most often used in concrete for construction. Portland cements contain calcium and silicon oxides together with additives such as alumina, ferrites, and gypsum. Cement clinker chemistry and the portland cement phases that form, including composition and reaction rates, are discussed. Cement hydration and structure are described as are properties such as strength and porosity of concretes. Chemical admixtures for concrete are also reviewed. Either a dry or a wet process may be used in cement manufacture; both are described. The uses of portland cements, special purpose and blended cements, and calcium aluminate cements are reviewed.
Ceramics As Electrical Materials
Authors: Buchanan Relva C. , Roseman Rodney D. 
Published: July 2004

Abstract
Ceramic materials contribute important component functions, including resistance, capacitance, magnetic inductance, and environmental sensing to a variety of microelectronics applications. The material choice may be based on dominant magnetic, ferroelectric, piezoelectric, pyroelectric, electrooptic, electrochemical, mechanical, or thermal properties, but the underlying function of primary importance is the electrical conductivity, which determines overall insulation behavior and device utility. Since the components are typically shaped by ceramic processes, understanding of their properties require detailed knowledge of the composition, crystal structure, microstructure, and processing conditions. The role of defects and substitution (stoichiometry) is important also in controlling electrical conduction, especially for materials containing one or more cations of variable valence. Defects likewise play a major role in the performance of ceramic sensor devices, which serve as the detecting or switching element in many circuit operations. The sensing operation is typically based on a sharp change in electrical conduction, which reflects a significant change in the thermal, chemical, mechanical, optical, electrical, or magnetic environment of the device. In this article, the basic definitions of electrical terms relating to conduction, dielectric, magnetic, and sensor properties are presented, but the primary focus is on the influence of the materials characteristics on the electrical properties detailed above, with emphasis on the electrical conductivity mechanisms for the different categories of materials.
Composite Materials, Ceramic‐Matrix
Authors: Butler E. P. , Fuller E. R. 
Published: July 2004

Abstract
Ceramic‐matrix composites are materials for use in high temperature structural applications. The intrinsic properties of the ceramic‐matrix such as high melting point, high chemical stability, high elastic modulus and hardness, high wear and creep resistance along with low mass density relative to metallic materials are coupled with the properties of high fracture resistance and flaw insensitivity when reinforced with a high strength second phase. The varieties of reinforcements include particles, platelets, whiskers, and continuous fibers. Placement of reinforcements within the matrix determines the isotropy of the composite properties. Particulate reinforced matrices derive their toughness from processes such as crack deflection, crack pinning and bowing, microcracking, and frictional bridging mechanisms. Whisker, platelet, and fiber‐reinforced matrices derive their toughness from crack‐wake frictional bridging and pull‐out mechanisms. For the mechanism of crack‐wake bridging the most important aspect of the composite is the interface between the reinforcement and the matrix. It must be weak enough to allow debonding around the reinforcement leaving it as an intact bridging element in the crack‐wake. Control of the interface between the matrix and reinforcements is extremely important in optimization of composite properties.
Bakery Processes, Chemical Leavening Agents
Authors: Chung Frank H. Y. 
Published: July 2004

AbstractChemical leavening involves the action of an acid on bicarbonate to release carbon dioxide gas for aeration of a dough or batter during mixing and baking. The aeration provides a light, porous cell structure, fine grain, and a texture with desirable appearance along with palatability to baked goods. There are essentially two components in a chemical leavening system: bicarbonate that supplies carbon dioxide gas and an acid which triggers the liberation of carbon dioxide from bicarbonate upon contact with moisture. Sodium bicarbonate (baking soda) is the primary source of carbon dioxide gas in practically all chemical leavening systems. The prevalent baking acids in modern chemical leavening systems are sodium or calcium salts of ortho, pyro, and complex phosphoric acids. Baking soda determines the amount of carbon dioxide evolved, whereas the type of acid controls the speed of liberation. By far, the greatest use of leavening in the home is in preleavened mixes. Pancake mixes, biscuit mixes, and cake mixes have long been established as commercial products. Sales of frozen or refrigerated doughs and batters have increased rapidly in recent years. This trend is attributable to increased refrigeration and freezer capacity in stores and to the development of new and improved ingredients. Practically all of the leavening acids used in the mix industry today are of the phosphate type. The blending of baking powder is essentially a physical mixing of the various components in a large‐scale batch mixer and is often carried out in automated plants.