bluuebunny/crossref_metadata_2025 huggingface dataset:
Adsorption, Gas Separation
Authors: Sherman John D. , Yon Carmen M.
Published: August 2004

Gas‐phase adsorption is widely employed for the large‐scale purification or bulk separation of air, natural gas, chemicals, and petrochemicals. An adsorbent attracts molecules from the gas, and the molecules become concentrated on the surface of the adsorbent and are removed from the gas phase. Most commercial adsorbents for gas‐phase applications are employed in the form of pellets, beads, or other granular shapes, most commonly packed into fixed beds through which the gaseous feed mixtures are passed. The growth in both variety and scale of gas‐phase adsorption separation processes, particularly since 1970, is due in part to continuing discoveries of new porous, high surface‐area adsorbent materials (particularly molecular sieve zeolites) and to improvements in the design and modification of adsorbents. To permit the recovery of pure products and to extend the adsorbent's useful life, adsorbents should generally be inert and not react with or catalyze reactions of adsorbate molecules. Commercially useful adsorbents can be classified by the nature of their structure (amorphous or crystalline), by the sizes of their pores, by the nature of their surfaces (polar, nonpolar, or intermediate), or by their chemical composition, of which the size of the pores is the most important initial consideration. Adsorption processes are temperature‐swing adsorption (TSA) and pressure‐swing (PSA) as well as purge‐swing cycles and nonregenerative approaches. Most adsorption processes use fixed beds, but some use moving or fluidized beds.
Genetic Engineering, Animals
Authors: Lucy Matthew , Collier Robert
Published: August 2004

A transgenic animal is an animal that has a modified gene inserted into its DNA. This modified or foreign gene is called a transgene. Transgenic animals are produced that either over or under express specific proteins within certain cells. This leads to animals having unique characteristics.

Agricultural uses of this technology include insertion of genes into farm animals for improved milk production, growth rate, and disease resistance. Biomedical uses of this technology include the development of lines of transgenic laboratory animals as experimental models for human diseases and the production of farm animals that produce recombinant pharmaceutical proteins in their milk. The production and use of transgenic laboratory and farm animals represents an evolving technology of engineering animal species for specific roles in science and agriculture.

One goal of animal agriculture is to exploit the superior genetics of animals. A technology that accomplishes this goal is artificial insemination. It is much more difficult to exploit the genetics of superior female cattle because they produce few gametes (ova). It is necessary to develop methods to mass produce identical copies of embryos that are collected from a superior female animal. Two methods are embryo splitting and embryo cloning.

It is possible to select superior embryos during their initial development. This process is used to test for and select embryo sex, milk protein genes and somatotropin genotype.
Bismuth and Bismuth Alloys
Authors: Chagnon Mark J.
Published: August 2004

The element bismuth, Bi, found in Group 15 (VA) of the Periodic Table, has at no. 83, at wt 208.98. Its valences are

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and

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. Bismuth is a silvery metal having a high metallic luster and exhibiting a slightly pink tinge on a cleanly broken surface. The metal itself is brittle in nature and easily broken. Bismuth is referred to as a minor metal. Bismuth occurs in the earth's crust in a concentration of approximately 0.1 ppm on the average. The physical properties of bismuth are characterized by a low melting point, a high density, and expansion on solidification. The thermal conductivity of bismuth is lower than that of any other metal except mercury. Bismuth is mined primarily as a by‐product of the processing of ores of other metals, mostly copper and lead. The principal portion of the bismuth in copper ores follows the copper into the matte. During the conversion of the matte to blister copper most of the bismuth fumes off. The fumes are caught in the baghouse or Cottrell system. The portion of the bismuth remaining with the blister copper is separated during the electrolytic refining in the slimes. The bismuth found in the lead ore accompanies the lead through the smelting operation right up to the last refining steps. Bismuth is leached from roasted tin concentrates and other bismuth‐bearing materials by means of hydrochloric acid. There are four basic forms of bismuth that are readily available commercially: ingot, needle, pellet, and powder. The three primary categories of uses of bismuth in industry are chemical, metallurgical additive, and fusible alloy. The chemical category can be broken down into pharmaceuticals, cosmetics, catalysts, industrial pigments, and electronics, and the metallurgical additive category into steel, aluminum, and cast‐iron additives. The fusible alloy category is divisible into more than a dozen subcategories dependent on a specific application. Because bismuth alloys with certain other metals to give low melting point alloys, bismuth is particularly well‐suited for a number of uses. No industrial poisoning from bismuth has been reported. Ingestion and inhalation of dusts and fumes should be avoided.
Boron, Elemental
Authors: Jansen Linda H.
Published: August 2004

Boron, B, is unique in that it is the only nonmetal in Group 13 (IIIA) of the Periodic Table. Boron, at wt 10.81, at no. 5, has more similarity to carbon and silicon than to the other elements in Group 13. There are two stable boron isotopes,10B and11B, which are naturally present at 19.10–20.31% and 79.69–80.90%, respectively. There is a very low cosmic abundance of boron. Boron is the 51st most common element present in the earth's crust at a concentration of three grams per metric ton. Elemental boron has a diverse and complex chemistry, influenced by its having a high ionization energy, 8.296 eV, 23.98 eV, and 37.75 eV for first, second, and third ionization potentials, respectively; by its small size; and by virtue of the electronegativities of boron (2.0), carbon (2.5), and hydrogen (2.1) all being very similar, resulting in extensive and unusual covalent chemistry. Boron has electronic structure (1s)2(2s)2(2p) and an expected valence of three. There is no formation of univalent compounds. Boron has a high affinity for oxygen‐forming borates, polyborates, borosilicates, peroxoborates, etc. Boron reacts with water at temperatures above 100°C to form boric acid and other boron compounds. In addition to being an amorphous powder, boron has four crystalline forms: α‐rhombohedral, β‐rhombohedral, α‐tetragonal, and β‐tetragonal. The α‐rhombohedral form has mp 2180°C, sublimes at approximately 3650°C, and has a density of 2.45 g/mL. Amorphous boron, by comparison, has mp 2300°C, sublimes at approximately 2550°C, and has a density of 2.35 g/mL. Boron is an extremely hard refractory solid having a hardness of 9.3 on Mohs' scale and a very low (\documentclass{article}\usepackage{amssymb}\pagestyle{empty}\begin{document}${1.5\times 10^{-6}{\hskip0.167em}{\hskip0.167em}{\rm{ohm}}^{-1}{\hskip0.265em}{\rm{cm}}{^{-1}}}$\end{document}room temperature electrical conductivity so that boron is classified as a metalloid or semiconductor. These values are for the α‐rhombohedral form. The high ionization energies and small size prevent boron from adopting metallic bonding to compensate for its electron deficiency and that of other hypoelectronic elements. A high purity (greater than 99%) boron comes from the direct thermal decomposition of boron hydrides such as diborane, B2H6. The Moissan process, the reduction of boric oxide with magnesium, is the most widely used commercial process for producing boron. Elemental boron is used in very diverse industries ranging from metallurgy to electronics. Other areas of application include ceramics, propulsion, pyrotechnics, and nuclear chemistry. Boron is nontoxic. Workplace hygienic practices include avoiding the breathing of boron dust.
Calcium Carbonate
Authors: Carr F. Patrick , Frederick David K.
Published: August 2004

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

Cerium 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

Citric 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

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

The 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

Engineering 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

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

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

The 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

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

Photochromism 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

The 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

Several 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

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

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

Sodium 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

Clays 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.
Chlorocarbons and Chlorohydrocarbons, Toxic Aromatics
Authors: Safe Stephen H.
Published: August 2004

Polychlorinated biphenyls (PCBs) and naphthalenes (PCNs) are halogenated aromatic industrial compounds produced and marketed for a wide variety of applications. PCBs were used as heat‐transfer fluids, organic diluents, lubricant inks, plasticizers, fire retardants, paint additives, sealing liquids, immersion oils, adhesives, dedusting agents, waxes, and as dielectric fluids for capacitors and transformers. PCNs were used as waxes and impregnants (for protective coatings), water repellents, and wood preservatives. PCBs have been identified as contaminants in almost every component of the global ecosystem including the air, water, sediments, fish, wildlife, and humans. PCNs are only infrequently detected because these products had been used much less than the commercial PCBs. The toxicology of PCBs has been extensively studied and the commercial mixtures elicit a broad spectrum of toxic and biochemical responses.

γ‐Lindane is a chlorinated hydrocarbon pesticide that has also been widely identified in the environment. The toxic responses elicited by γ‐lindane in laboratory animals include hepato‐ and nephrotoxicity, reproductive and embryotoxicity, mutagenicity in some short termin vitrobioassays, and carcinogenicity. Only minimal data are available on the mammalian toxicities of hexachlorocyclopentadiene. The impact of environmental exposure to γ‐lindane is unknown and only minimal toxic effects have been observed in occupationally‐exposed individuals.
Fibers, Vegetable
Authors: Young Raymond A.
Published: August 2004

Plant‐derived vegetable fibers are classified according to their source in plants as bast, leaf, or seed‐hair. The fibers in bast and leaf plants are integral to the plant structure, providing strength and support. The principal chemical component of vegetable fibers is cellulose, with varying amounts of lignin and hemicelluloses also usually present; thus the fibers are also referred to as cellulosic or lignocellulosic. Vegetable fibers are usually stiffer but less tough than synthetic fibers. The fibers are grown throughout the world but mostly in tropical and subtropical climates in developing countries. The principal bast fibers are flax, jute, and hemp which are utilized primarily for fabrics (linen‐flax, hessian‐jute), bags, ropes, and as a source of papermaking fibers, principally cigarette papers. The primary leaf fibers are abaca and sisal, which have uses similar to bast fibers, except fabrics are not produced from the leaf fibers. Cotton, coir, and kapok are the principal seed‐hair fibers, with cotton by far the most important commercial vegetable fiber. Bast fibers are obtained from the plant, after harvest, by water retting (rotting) in ponds or streams. The leaf fibers are obtained by crushing and scraping followed by washing. Vegetable fibers are generally graded according to color, luster, cleanliness, strength, fineness, and uniformity. The world market for vegetable fibers has dropped over 30% in recent years because periods of economic recession and synthetic fiber replacements.
White Blankets May make you Smarter and other Questionable Social Science Findings
Authors: Blimling Gregory S.
Published: August 2004

Looking for amazing research that will make the nightly news or turn an administrator's head? If you find it, be warned. The findings may have been reported out of context or based on faulty logic.
Modifying irregular titania powders in a low power microwave plasma torch
Authors: Vanamu Ganesh , Lester Kelvin , Datye Abhaya K. , Weigle John C. , Chen Chun‐Ku , Kelly Daniel , Phillips Jonathan
Published: August 2004

Rapid passage of titania powder as an aerosol through a plasma generated with a low power microwave torch, resulted in many changes to the powder. Some or all of the titania became spherical, its phase changed, the level of carbon impurity changed, and its surface area declined. The final state of the titania depended on plasma operating conditions. For example, all of the titania became spherical and converted to the rutile phase, only if the processing rate remained low. Complete spherodization occurred only if the energy absorbed by the particles was <2.5% of the total power applied. Excess solid loading reduced the fraction spherodized or otherwise modified, as well as the net rate of conversion. Passing titania through an oxygen plasma removed virtually all the carbon impurity. This process is similar to alumina studies in the same apparatus and suggests that many refractory oxides can be modified by low‐power plasmas. © 2004 American Institute of Chemical Engineers AIChE J, 50: 2090–2100, 2004
Body fatness and clustering of cardiovascular disease risk factors in Portuguese children and adolescents
Authors: Ribeiro José Carlos , Guerra Sandra , Oliveira José , Andersen Lars Bo , Duarte José Alberto , Mota Jorge
Published: August 2004

Modifiable cardiovascular risk factors that increase the risk for cardiovascular diseases (CVD) in adult populations have also been observed in pediatric populations. Childhood and adolescence obesity has been strongly implicated in the clustering of risk factors. The aims of the present study were 1) to examine whether clustering of CVD risk factors, either biological risk factors (high blood pressure (HBP), percentage of high fat mass (%HBF), and high total cholesterol (HTC)) and one behavioral/lifestyle risk factor (low physical activity index (LPAI)) exist, and 2) to analyze the relationship between body fatness and the clustering of other risk factors. The cluster of CVD risk factors was determined in 1,533 (8–15 years of age) children, 731 males (age 10.8 ± 2.3 years; weight, 40.6 ± 12.7 kg; height, 143.1 ± 14.1 cm; BMI, 19.4 ± 3.4 kg−2) and 802 females (age, 11.0 ± 2.4; weight, 41.0 ± 12.4; height, 142.8 ± 13.2; BMI, 19.7 ± 3.5). Sex‐ and age‐specific “high risk” quartiles were formed for each of the biological risk factors and the lifestyle factor. Thus, for blood pressure (high blood pressure, HBP), cholesterol (high cholesterol, HTC), and obesity (high percent of body fat, HBF), the sex‐ and age‐adjusted 4th quartile (4Q) was defined as the “high risk” quartile, while for physical activity the 1st quartile (1Q) was defined as the “high risk” quartile. The majority of children (62% of boys and 62% of girls) at risk of obesity are at risk of another risk factor. In our sample, estimated ORs indicated that, compared with 1Q, the “risk of obesity” children and adolescents were two times as likely (P < 0.001) to have two or three risk factors. Our results suggest that children 8–15 years old in the highest quartile of body fatness are an increased risk of having a cluster of other risk factors, namely HBP, HTC, and LPAI. These data provide further evidence that juvenile obesity warrants early intervention because the patterns of unhealthy behavior are formed in adolescence and young adulthood. Am. J. Hum. Biol. 16:556–562, 2004. © 2004 Wiley‐Liss, Inc.
Peak oxygen uptake in relation to age, sex, and maturation in Hong Kong Chinese children
Authors: McManus Alison M. , Chung Yung Tak , Leung Maurice P.
Published: August 2004

This cross‐sectional study was designed to provide baseline information on peak oxygen uptake for Southern Chinese children in relation to age and sexual maturation. Sixty‐three boys and 84 girls, classified for stage of sexual maturation using Tanner's stages, successfully completed a peak oxygen uptake test. ANOVA was used to examine differences in absolute and mass‐related peak VO2. The least‐squares log‐linear relationship between mass and peak VO2 was examined using analysis of covariance. We found no difference between boys' and girls' peak VO2 prior to puberty. Absolute peak VO2 values for under‐10‐year‐old Chinese girls and boys were 17% and 19%, respectively, lower than Caucasian predicted values. Log‐linear adjusted means for prepubertal boys and girls were 34% and 33% lower than Caucasian boys and girls, respectively. By adolescence, values were comparable to Caucasian values. South Chinese children show a distinct pattern of development relative to Caucasian children, particularly in the younger age groups. Am. J. Hum. Biol. 16:602–605, 2004. © 2004 Wiley‐Liss, Inc.
Energetic factors and seasonal changes in ovarian function in women from rural Poland
Authors: Jasienska Grazyna , Ellison Peter T.
Published: August 2004

Female mammals can optimize their fitness by temporal suppression of reproductive function in response to unfavorable environmental conditions. Since reproduction is energetically demanding for a human female, ovarian function is expected to be sensitive to factors influencing energy availability and metabolism. Dieting and exercise in women from industrial countries, and low‐calorie diet and workload in women from developing countries, are often associated with ovarian suppression. This study shows that in Polish rural women seasonal changes in workload correlate with seasonal changes in indices of ovarian function (progesterone measured in saliva samples collected daily for six menstrual cycles for each subject). Mean levels of energy expenditure of the most work demanding weeks of the summer exceeded mean levels of energy expenditure during winter by 37%. Energy intake in this population was sufficient throughout the year. During the summer, when physical work was most intense, low values of progesterone levels were observed (178.2 pmol/L in July and 182.2 pmol/L in August), indicating ovarian suppression. Mean progesterone levels rose to 234.6 pmol/L in October when levels of energy expenditure were lower due to cessation of harvest‐related activities. As indicated by several causal models tested through path analysis, energy expenditure was the only variable responsible for suppressed progesterone levels during the summer. Variables describing the nutritional status and energy balance did not correlate significantly with progesterone levels; neither body weight nor body fat or seasonal changes of these variables seem to influence ovarian function in this population. Thus work‐related energy expenditure does not need to lead to negative energy balance in order to cause suppression of reproductive function in women. Am. J. Hum. Biol. 16:563–580, 2004. © 2004 Wiley‐Liss, Inc.
Ecogeographic size variations in sifakas: A test of the resource seasonality and resource quality hypotheses
Authors: Lehman Shawn M. , Mayor Mireya , Wright Patricia C.
Published: August 2004

Ecogeographic size variations have been documented in some but not all sifakas. Few morphometric or body weight data have been available for two critically endangered subspecies of diademed sifakas: Perrier's sifakas (Propithecus diadema perrieri) and silky sifakas (Propithecus diadema candidus). The objectives of our study were to determine size variations in sifakas and if these variations are related to resource quality and/or resource seasonality. P. d. perrieri and P. d. candidus were captured, weighed, and measured in northern Madagascar. Body weights and morphometrics were compared with other subspecies of diademed sifakas and indris (Indri indri). Differences in body weights and morphometrics between taxa are particularly pronounced for P. d. perrieri compared to P. d. diadema, P. d. edwardsi, and I. indri. Most morphometrics varied in comparisons between P. d. candidus and the other Indriidae (P. d. diadema, P. d. edwardsi, and I. indri). Average body size in sifakas is positively correlated with annual rainfall and negatively correlated with length of dry season. Sifaka body size is not correlated with protein‐to‐fiber ratios. Thus, size variations in sifakas are related to resource seasonality rather than resource quality. The relationships between the temporal availability of food resources and sifaka body size reflect complex and regionally varying causalities. Detailed, longitudinal information on the ecological factors underlying food selection and nutrient requirements in sifakas are needed to determine the relationship between ecogeographic variables and body size in sifakas. Am J Phys Anthropol, 2004. © 2004 Wiley‐Liss, Inc.
Glucose hypometabolism of hypothalamus and thalamus in narcolepsy
Authors: Joo Eun Yeon , Tae Woo Suk , Kim Jee Hyun , Kim Byung Tae , Hong Seung Bong
Published: August 2004

It has been hypothesized that hypothalamus is involved in narcolepsy. The relative difference between cerebral glucose metabolism of 24 narcoleptic patients and 24 normal controls was studied using 18F‐fluorodeoxy glucose positron emission tomography. Patients with narcolepsy showed significantly reduced cerebral glucose metabolism in bilateral rectal and subcallosal gyri, the medial convexity of right superior frontal gyrus, bilateral precuneus, right inferior parietal lobule, and in left supramarginal gyrus (uncorrected p < 0.001). Bilateral posterior hypothalami and mediodorsal thalamic nuclei showed hypometabolism with significance at the level of corrected p < 0.05, with small volume correction. This study showed cerebral glucose hypometabolism of the hypothalamus‐thalamus‐orbitofrontal pathways in the narcoleptic brain. Ann Neurol 2004
Cover Picture: Structural Revision and Total Synthesis of Azaspiracid‐1, Part 1: Intelligence Gathering and Tentative Proposal (Angew. Chem. Int. Ed. 33/2004)
Authors: Nicolaou K. C. , Vyskocil Stepan , Koftis Theocharis V. , Yamada Yoichi M. A. , Ling Taotao , Chen David Y.‐K. , Tang Wenjun , Petrovic Goran , Frederick Michael O. , Li Yiwei , Satake Masayuki
Published: August 2004

The mussel toxin azaspiracid‐1, which was isolated from Mytilus edulis, has baffled chemists for quite some time, as the originally proposed structure was incorrect. In their Communications on pages 4312 ff. and 4318 ff., Nicolaou and co‐workers describe how they determined the structure and absolute configuration of the molecule through degradation studies and total synthesis. The synthesis should render this valuable, but scarce, substance available for much‐needed biotoxin assays and biological investigations.
Crystallographic report: A synthetic precursor for hetero‐binuclear metal complexes, [Ru(bpy)(dppy)2(CO)2](PF6)2 (bpy = 2,2′‐bipyridine, dppy = 2‐(diphenylphosphino)pyridine)
Authors: Ooyama Dai , Sato Masahito
Published: August 2004

In the title complex, [Ru(bpy)(dppy)2(CO)2](PF6)2 (bpy = 2,2′‐bipyridine, dppy = 2‐(diphenylphosphino)pyridine), the ruthenium atom exhibits a slightly distorted octahedral coordination with the carbonyl ligands in cis positions. In addition, two dppy ligands coordinate to the ruthenium center through the phosphorus atoms in mutually trans positions and two pyridyl nitrogen atoms of the dppy direct toward two carbonyl ligands. Copyright © 2004 John Wiley & Sons, Ltd.
Crystallographic report: Crystal and molecular structure of triphenyltin thiazole‐2‐carboxylate
Authors: Yin Han‐Dong , Wang Chuan‐Hua
Published: August 2004

The tin atom in the title compound is in a distorted C3O tetrahedral geometry, as the carboxylate ligand is effectively monodentate. Copyright © 2004 John Wiley & Sons, Ltd.
Crystallographic report: catena‐Poly[aqua(phenyl‐1,3‐bisoxyacetato) tris(pyridine)cadmium(II)], [(H2O)(C5H5N)3 (O2CCH2OC6H4OCH2CO2)Cd]n
Authors: Gao Shan , Liu Ji‐Wei , Ng Seik Weng
Published: August 2004

The [O2CCH2OC6H4OCH2CO2]2− group bridges adjacent planar [(H2O)(C5H5N)3Cd]2+ units into a linear chain. The carboxyl groups occupy opposite sites in the octahedral environment of the cadmium atom. Copyright © 2004 John Wiley & Sons, Ltd.