bluuebunny/crossref_metadata_2025_split huggingface dataset:
Calcium Carbonate
Authors: Carr F. Patrick , Frederick David K. 
Published: August 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.
Cerium and Cerium Compounds
Authors: Kilbourn Barry T. 
Published: August 2004

AbstractCerium is the most abundant member of the lanthanide series, those elements having 4felectrons. It is found in nature in the presence of other lanthanides and this mix is often used commercially as a cerium source without separation. Mischmetal, a metallic mix of cerium and other of the lighter lanthanides, is used in the steel industry, in lighter flints, and as getters. Lanthanide concentrate, an oxide mix that includes cerium oxide, is used in some fluid cracking catalysts.Cerium is unique within the lanthanide series because it has two stable oxidation states. Many of the uses of cerium and cerium compounds center around the redox chemistry of the Ce(IV)/Ce(III) couple. Cerium oxide acts as a stabilizer improving oxidation resistance for alloy systems, polymers, and automotive catalytic converter catalysts. Cerium compounds are present in optical coatings, in phosphors for cathode ray tubes, and in paints.
Citric Acid
Authors: Blair Gary , Staal Philip 
Published: August 2004

AbstractCitric acid is a natural component and common metabolite of plants and animals. It is the most versatile and widely used organic acid in foods, beverages, and pharmaceuticals.Because of its functionality and environmental acceptability, citric acid and its salts (primarily sodium and potassium) are used in many industrial applications for chelation, buffering, pH adjustment, and derivitization. These uses include laundry detergents, shampoos and cosmetics, enhanced oil recovery, and metal cleaning.This article details the physical and chemical properties of citric acid, its occurrence in nature, and commercial manufacturing, processing, shipping, and storage information. Descriptions are given of the two common methods to recover citric acid from its fermentation broth: lime‐sulfuric acid recovery and also liquid extraction.Commercial considerations including worldwide production are reviewed, along with comparisons of various national compendial specifications for citric acid and common analytical test methods.
Colorants for Plastics
Authors: Beebe Gary 
Published: August 2004

Abstract
Colorants are used to impart aesthetics to plastics to provide for the ever‐increasing choice of products offered to today's markets and to allow producers to differentiate their goods. To accommodate myriad production techniques, colorants are available in many forms: dry colorants, dispersions, color concentrates, and liquid colorants. Sometimes they are directly blended into resins.
In addition to coloring, the polymer colorants often have an effect on the properties of the intended product's application. Colorants affect the weatherability of a product and may change the optical, mechanical, chemical thermal, and electrical performance of the plastic. Also, there are regulatory and safety concerns that are present with certain colorants.
Colorants can be classified into three groups: inorganic pigments, organic pigments, and dyes. Pigments do not become part of the resin system and need to be thoroughly dispersed in the resin for optimum coloration. Dyes are soluble in the resin and become part of the resin. The description of the most commonly used colorants includes their chemical makeup and examples of their features and typical applications.
Copolymers
Authors: Costello Christine A. , Schulz Donald N. 
Published: August 2004

AbstractThe preparation, properties, characterization, use, economic importance, and future of synthetic copolymers are reviewed. The theory of copolymerization is explained for chain‐growth polymers. Literature values of reactivity ratios for various synthetic methods indicate that different types of polymers are obtained, depending on the synthetic method employed. The effect of monomer unit arrangement in copolymers is presented. Emphasis is placed on its effect on physical properties such as glass‐transition temperature, morphology, and mechanical properties. Industrially important random, alternating, block, and graft copolymers are discussed with respect to their economic importance (industrial sources and amounts produced). Finally, the future trends in copolymer synthesis are addressed. Applying new polymer synthesis techniques (eg, group‐transfer polymerization and ring‐opening olefin metathesis) to make well‐tailored copolymers is stressed.
Engineering Plastics
Authors: Clagett Donald , Narr Raymond 
Published: August 2004

AbstractEngineering plastics are of several generic types and, considering the rapid advances in polymerization, blending, alloying, filling, reinforcing, and reactive compounding technologies, the boundaries of their definition have become increasingly blurred. They may be “plastics which lend themselves to use for engineering design, such as gears and structural members” or thermoplastic resins (neat or unreinforced), or filled, which maintain dimensional stability and most mechanical properties above 100C and below 0C. The latter definition encompasses plastics that can be formed into functional parts that can bear loads and withstand abuse in temperature environments commonly tolerated by the traditional engineering materials, ie, wood, metals, glass, and ceramics. Examples include acetal resins, polyamides (nylons), polyimides, polyetherimides, polyesters, liquid‐crystal polymers, selected polyolefins, blends or alloys of the foregoing resins, and polycarbonates, poly(phenylene sulfide), modified poly(phenylene oxide), polysulfone, and polyarylates. The structure, properties, applications, and market share of these materials are discussed.
Groundwater Monitoring
Authors: Miller Carol J. 
Published: August 2004

Abstract
Groundwater monitoring is used to analyze the impact of a variety of surface and subsurface activities, including seawater intrusion, application of agricultural products such as herbicides, pesticides, and fertilizers, residential septic systems, and industrial waste ponds. Another focus of groundwater monitoring has been contamination associated with waste landfills and ruptured underground petroleum storage tanks.
The design of a groundwater monitoring strategy requires a basic understanding of groundwater flow systems. The majority of groundwater flow occurs in formations known as aquifers. At least two types of data can be retrieved using groundwater wells, ie, groundwater pressure and groundwater quality. A monitoring well allows measurement of these properties at a specific point in an aquifer. Monitoring wells come in a variety of sizes and materials, but each is simply a pipe extending from the ground surface to a point in theaquifer at which the pressure or contaminant is to be assessed. Monitoring wells are functional only in the saturated zone of the subsurface. Within the unsaturated soil zone, tensiometers, soil moisture blocks, and psychrometers have been used to assess fluid pressures. Fluid samples are retrieved using suction cup lysimeters for subsequent quality analysis.
Aluminum Oxide (Alumina), Hydrated
Authors: Misra Chanakya 
Published: August 2004

Abstract

The term alumina hydrates or hydrated aluminas is used in industry and commerce to designate aluminum hydroxides. These compounds are true hydroxides and do not contain water of hydration. The most well‐defined crystalline forms are the trihydroxides, Al(OH)
3
: gibbsite, bayerite, and nordstrandite. In addition, two aluminum oxide–hydroxides, AlO(OH), boehmite and diaspore, have been clearly defined. The terms gelatinous alumina or alumina gel cover a range of products in which colloidal hydrated alumina is the predominant solid phase. Structural order varies from x‐ray indifferent (amorphous) to some degree of crystallinity. Apart from the crystalline forms, aluminum hydroxide often forms a gel. Gel products have considerable technical use. Aluminum hydroxides are technically the most widely used members of the alumina chemicals family. The most important source of aluminum hydroxides is the bauxite refining plant (Bayer process) for alumina production. Several commercial grades of aluminum hydroxide are produced. Hydroxide grades can be surface‐treated to modify dispersion behavior and rheological properties. Aluminum hydroxides are minimally absorbed by the body. Death upon ingestion occurs from intestinal blockage rather than systemic aluminum toxicity. In recognition of the possible adverse effects of long‐term exposure to alumina dusts, threshold limit values have been established by the ACGIH. Aluminum hydroxide and aluminum hydroxide oxide are reported in EPA TSCA inventory.
Lignin
Authors: Lin Stephen Y. , Lebo Stuart E. 
Published: August 2004

AbstractThe word lignin is derived from the latin wordlignummeaning wood. It is one of the main components of all vascular plants and the second most abundant polymer in nature. This article describes the current understanding of the structure of this complex natural polymer. The number and types of different chemical bonds present in lignin are discussed as are the ways in which different lignins are identified and their distributions determined in plant tissues. Means for isolating lignin from wood are described, and the chemical and physical properties of the resulting lignins are reviewed. The various chemical and instrumental methods for characterizing isolated lignins are also discussed. The article concludes with a review of commercial lignin products including a discussion of producers, production methods, modification reactions, and the many industries in which lignins are used.
Feeds and Feed Additives, Nonruminant Feeds
Authors: Waldroup Park W. 
Published: August 2004

Abstract
Nonruminant animals such as swine and poultry contribute significantly to the food supply of the human population. Feeds for these animals consist of grains, oilseed meals, and many miscellaneous human and industrial by‐products in addition to a variety of feed additives. Requirements for all essential nutrients required by swine and poultry are well defined, and the nutrient content of most common feedstuffs has been determined. Swine and poultry diets are typically well fortified with supplemental vitamins and trace minerals. Feed additives are used for a number of purposes, although primarily to promote animal health and improve growth performance. Virtually all poultry feed and a growing percentage of swine feed is produced by vertically integrated producers.
Chromogenic Materials, Photochromic
Authors: Crano John C. 
Published: August 2004

AbstractPhotochromism has been defined as a reversible change in the color, or darkening, of a material caused by absorption of ultraviolet or visible light. The change in color implies a change in the absorption spectrum in the visible range of light (400–700 nm). The reversion of the system to its original state can be driven either by thermal or photochemical energy (photobleaching), or both.Photochromic systems are naturally separated into two broad categories, inorganic and organic. Within the inorganic category, the most well‐studied and commercially utilized systems are those containing silver halide crystallites dispersed throughout a glass matrix. The mechanism of the silver halide photochromism is the reversible formation of silver metal. Both the photochemical formation of silver and the thermal reformation of silver halide are catalyzed by copper ions. The silver halide glass systems have been used commercially in photochromic eyewear.There are several types of organic photochromic systems involving a multitude of mechanisms. Most common are those that involve electrocyclic reactions and within this class, the indolino spiropyrans and spiroxazines have received the most attention. Indolino spiroxazines were the first photochromic compounds utilized in the preparation of commercially acceptable organic photochromic lenses for ophthalmic applications.
Platinum‐Group Metals
Authors: Seymour Richard J. , O'Farrelly Julia I. , Potter Louise C. 
Published: August 2004

AbstractThe platinum‐group metals, ie, platinum, palladium, rhodium, ruthenium, osmium, and iridium, all have high melting points and exceptional corrosion resistance. Platinum, rhodium, and iridium are particularly stable to oxidation at high temperatures. These metals, especially platinum and palladium, show exceptional catalytic properties.In nature, platinum‐group metals frequently occur in conjunction with nickel, copper, and iron sulfides. The principal producing region is South Africa, but other commercially important deposits exist in Canada and CIS. In the refining of these metals, solvent extraction technology is increasingly replacing conventional hydrometallurgical processes. Benefits include increased recovery, improved efficiency, and significantly shortened process time. Resources and recovery processes are discussed.The platinum‐group metals are extensively used as catalysts. Applications include pollution control catalysts for gasoline and diesel vehicles, control of emissions of organics and nitrous oxides from industrial installations, fuel cells and process catalysts in the chemical industry, including nitric acid and chlorine production, and petroleum organic synthesis refining. Platinum‐group metals are also used as jewelry, in the glass industry, in electronic components, in spark plugs, on turbine blades, and in medical devices. Modern cardiovascular surgery and anticancer chemotherapy both employ these metals.
Polyethers
Authors: Crandall Louise W. , Hamill Robert L. 
Published: August 2004

AbstractSeveral polyether antibiotics have found commercial application as anticoccidials in poultry farming and in improvement of feed efficiency for ruminants. These antibiotics are characterized by multiple tetrahydrofuran and tetrahydropyran rings connected by aliphatic bridges, direct C–C linkage, or spiro linkage. Other features include a free carboxyl function, many lower alkyl groups, and a variety of functional oxygen groups. These structural features enable transport of cations across lipid membranes. Some polyethers have found application as components in ion‐selective electrodes for use in clinical medicine or in laboratory studies involving transport studies or measurement of transmembrane electrical potential. The polyether class can be subdivided based on the number of carbon atoms in the backbone, ie, longest chain of contiguous carbons between the carboxyl group and the terminal carbon. The 30 C skeleton group accounts for about 60% of the polyethers for which structures have been determined. Monensin, widely used as an anticoccidial and feed efficiency enhancer, is an example of the 26 C backbone class. Maduramicin, another commercially important polyether, is shown as an example of the 30 C group with a sugar moeity. Many of the production procedures for polyethens utilize the separation of the mycelium followed by extraction using solvents such as methanol or acetone. A number of the polyethers can be readily crystallized. Polyethers such as monensin, lasalocid, salinomycin, and narasin are sold in many countries in crystalline or highly purified forms for incorporation into feeds or sustained‐release bolus devices. There are also mycelial or biomass products, especially in the United States, generally prepared by separation of the mycelium and then drying by azeotropic evaporation, fluid‐bed driers, or other types of commercial driers. The polyether antibiotics exhibit a broad range of biological, antibacterial, antifungal, antiviral, anticoccidial, antiparasitic, and insecticidal activities. They improve feed efficiency and growth performance in ruminant and monogastric animals. Only the anticoccidial activity in poultry and cattle, and the effect on feed efficiency in ruminants such as cattle and sheep are of commercial interest. It is estimated that the polyether ionophores constitute more than 80% of the total worldwide usage of anticoccidials. Bacteria belonging to the order Actinomycetales are the organisms reported to produce all of the polyethers. Most are secondary metabolites ofStreptomycessp. with the specieshygroscopicusandalbusaccounting for about one‐third of the antibiotics. Monensin and salinomycin represent about 65–70% of worldwide usage of polyether antibiotics for controlling coccidiosis. Lasalocid, narasin, and maduramicin make up the remainder. Other compounds for coccidiosis control include nicarbazine, halofunginone, amprolium, and robenidine.
Polyesters, Unsaturated
Authors: Selley Jeffrey 
Published: August 2004

Abstract
Unsaturated polyester resins have been used commercially since the 1940s, establishing markets for reinforced composite plastics derived from combinations with glass fiber reinforcements. The availability of a wide variety of raw materials has encouraged the emergence of a diverse range of resins specifically tailored for many unique products. Fiber glass‐reinforced plastics (FRP) technology facilitates the production of large fabricated products, such as chemical and petroleum storage tanks, and a wide range of marine craft where low cost ambient processing provides competitive advantages. The technology has also evolved for high temperature automatic molding of high volume body components used for automobiles, trucks, and recreation vehicles. Polyester resins are also used extensively in highly filled cast products for kitchen and bathroom countertop applications; polyester polymer concrete provides corrosion‐resistant surfacing for highways and bridges. High performance resins are formulated to provide optimal corrosion and thermal performance in composite products designed for the chemical process industries. Under the mandates of the U.S. Clean Air and Clean Water Regulations, FRP pipe has emerged as a cost‐effective solution to upgrade inner city sewer systems, and FRP duct and scrubber systems are used widely in the pulp, paper, and electrical power industries to contain noxious emissions.
Feeds and Feed Additives, Ruminant Feeds
Authors: Sunvold Gregory D. , Fahey George C. 
Published: August 2004

Abstract
This article discusses feedstuffs and feed additives that are incorporated into ruminant diets based on various physiological states of the animal. The ruminant animal is unique because it can utilize highly fibrous feedstuffs unsuitable for consumption by monogastrics. Primary feedstuffs include forages/roughages, high energy feeds, supplements, feed additives, and young animal feeds. Forages/roughages (fibrous feeds) are the predominant feedstuffs consumed by ruminants throughout their lifetimes. Ruminants consume fibrous feeds either by grazing or by being fed preharvested forage. High energy feeds are those that are more energy‐dense than forages/roughages. These consist primarily of readily fermentable carbohydrates (grains) and lipids (animal or plant origin). Several supplemental sources of protein, energy, macrominerals, microminerals, and vitamins are discussed. Primary classes of feed additives include ionophores, ion‐exchange compounds, direct‐fed microbials, bloat preventatives, ruminal buffers, defaunation agents, hormones, antibiotics, and miscellaneous compounds. Situations in which young ruminants consume feed other than mother's milk are discussed. Various feed sources for these young animals are identified. Because of the extreme diversity in ruminant production systems, the sources of ruminant feedstuffs are extremely diverse.
Alkali and Chlorine Products, Sodium Carbonate
Authors: Rauh Francis 
Published: August 2004

AbstractSodium carbonate, Na2CO3, formula wt 105.99, is a white crystalline solid known as soda ash and, less commonly, ash, soda, or calcined soda. It is readily soluble in water and in strongly alkaline. It is the eleventh largest world commodity chemical. About 75% of world production is synthetic ash made from sodium chloride and limestone via the Solvay or similar processes; the remaining 25% is produced from natural sodium carbonate‐bearing deposits. Over half of the world's production is consumed in the glass industry, and another 22% is used in the production of sodium‐based chemicals. Sodium carbonate is also used in detergents, pulp and paper, and environmental control (water treatment and flue gas desulfurization). The normal article of commerce is highly purified (\documentclass{article}\usepackage{amssymb}\pagestyle{empty}\begin{document}${{\rm{>}}99{\%}}$\end{document}). Aqueous solutions are alkaline. At 25°C the pH of 1, 5, and 10 wt % Na2CO3solutions is 11.37, 11.58, and 11.70, respectively. Under National Fire Production Association (NFPA) Designation 704, soda ash is classified as a moderate health hazard. Exposure to soda ash dust may cause severe eye and slight nose and throat irritation. Traditional synthetic soda ash plants produce large volumes of aqueous, chloride‐containing waste which must be discharged. This fact, is largely responsible for the demise of U.S. synthetic plants. The natural soda ash processes produce no large volumes of associated wastes. By‐products and coproducts include calcium chloride, ammonium chloride, sodium bicarbonate, and sodium hydroxide.
Clays, Survey
Authors: Dombrowski T. 
Published: August 2004

AbstractClays are distinctive in at least two properties: plasticity and composition. Wetted clay deforms by application of relatively slight pressure retaining the deformed shape after release of the pressure. Clays are predominantly composed of hydrous phyllosillicates, called clay minerals, which exist in layers within the clay particles. The various minerals differ with regard to structure of the alternating layers, water content, and associated cations.The crystalline and paracrystalline groups of clay are presented as is the reliance of clay properties on composition and particle size. The surface area of the clay particles, often colloidal in size and usually platelike in shape, often dictates clay properties. The origin and locations of the various clays are discussed. Clay mineralogy is presented.