bluuebunny/crossref_metadata_2025_split huggingface dataset:
Silicones
Authors: Butts Matthew , Cella James , Wood Christina Darkangelo , Gillette Gregory , Kerboua Rachid , Leman John , Lewis Larry , Rubinsztajn Slawomir , Schattenmann Florian , Stein Judith , Wicht Denyce , Rajaraman Suresh , Wengrovius Jeffrey 
Published: July 2004

AbstractSilicon are a class of materials with unique properties that make them useful in a variety of applications of commercial interest and support a thriving global industry. This article updates a comprehensive survey of the chemistry and technology of silicones last published in Kirk‐Othmer Encyclopedia of Chemical Technology in 1997. The update contains more than 235 references not cited in the previous version and includes literature published through 2001. A new section dealing with fiber finishing applications has been included in the current version. The review provides an excellent primary reference for this interesting area of chemistry and technology.
Silver Compounds
Authors: Etris Samuel F. , Cappel C. Robert 
Published: July 2004

AbstractMost silver compounds are made from aqueous silver nitrate, which in turn is made from silver metal. Silver compounds are found in nature, but are neither ubiquitous nor prevalent. Silver salts are therefore expensive. Much of the silver produced annually in the United States comes from recycled metal. The primary usage of silver compounds occurs in the photographic industry. Silver compounds are also utilized in batteries, as catalysts, to form the reflective backings of mirrors, and for electroplating silver. Silver(I) compounds and complexes are the most stable, although some materials of higher silver oxidation are known. Some aqueous silver solutions serve as antiseptics; others as analytic reagents.
Silicon Compounds, Silylating Agents
Authors: Pape Peter G. 
Published: July 2004

Abstract
Silylating agents are used to replace active hydrogens from the surface of organic materials by trisubstituted silyl groups. This procedure is effected for a variety of reasons. Simple organic compounds may be silylated for purposes of synthesis and analysis; inorganic mineral surfaces may be silylated for purposes of analysis, adhesion, and water repellence; metal oxides, glass, resins, enzymes, etc, may be silylated to effect corrosion resistance, antimicrobial activity, immobilization for catalysis, chromatography column material, waterproofing, etc. The various compounds and the methods utilized for silylation are discussed.
Separation, Size Separation
Authors: Luckie Peter 
Published: July 2004

Abstract
Size separation, an important industrial unit operation, is a solid–solid separation process that produces minimally two streams from a feed stream of particles: one of coarser particles and one of finer particles. Devices that perform such separations fall into two general categories: those that separate by passing particles through apertures (screening) and those that separate using the forces of fluid dynamics (classification).
The performance of a separating device can be characterized by its size selectivity curve which, in turn, can be characterized by three parameters that describe completely the separation capability of a device. These parameters, which depend on the size of particles as well as on the design of the equipment, can also be used to predict the separation.
Size separation devices include inclined vibrating and stationary screens, probability screens, settling‐pool classifiers, hydrocyclones, mechanical classifiers, free and forced vortex classifiers, and transverse flow classifiers. The separation achieved by a single unit can be improved by staging several units in prescribed configurations. Pneumatic classification systems should be designed to handle hazardous dust.
Size Reduction
Authors: Prior Michael 
Published: July 2004

Abstract
Size reduction is an extremely important unit operation, whereby materials are subjected to stress in order to reduce the size of individual pieces. The stress is applied by transmitting mechanical force to the solid.
This article covers particle breakage and fracture mechanics, models predicting grindability and energy requirements, prediction of particle‐size distribution, and methods of applying stress. Stress can be applied by impact, crushing, cutting, or by stressing the surrounding medium, or by nonmechanical methods. The principal properties of particles that need to be considered in size reduction are toughness/brittleness, hardness, abrasiveness, feed size, cohesity, particle shape and structure, heat sensitivity, toxicity, explodability, and specific surface.
Typical size‐reduction equipment includes jaw crushers, roller mills, cone crushers, ball mills, rod mills, hammer mills, pin disk mills, turbine mills, jet mills, and cutting mills. Wet grinding is also employed.
Smart Materials
Authors: Harvey James A. 
Published: July 2004

AbstractFrom a technical and simple point of view a smart material is a material that responses to its environments in a timely manner. To expand on this definition a smart material is one that receives, transmits, or processes a stimulus and responds by producing a useful effect, which may include a signal that the material is acting upon it. Stimuli may include strain, stress, temperature, chemicals, an electric field, a magnetic field, hydrostatic pressures, different types of radiation, and other forms of stimuli. Transmission or processing of the stimulus may be in the form of an absorption of a photon, of a chemical reaction, of an integration of a series of events, of a translation or rotation of segments within the molecular structure, of a creation and motion of crystallographic defects or other localized conformations, of an alteration of localized stress and strain fields, and of others. The useful effects produced could be a color change, an index of refraction change, a stress or strain distribution change or a volume change. Also, incorporation within the definition of smart materials is the ability to be reversible.Under the proper set of environments and circumstances all materials are smart and depict smart behavior at some point during their life cycle. Some examples of technically smart behaving materials given in this article are piezoelectric materials, electrostrictive materials, magnetostrictive materials, electrorheological materials, magnetorheological materials, thermoresponsive materials, pH‐sensitive materials, uv‐sensitive materials, smart polymers, smart gels (hydrogels), smart catalysts, and shape memory alloys.
Soap
Authors: Bartolo Robert G. , Lynch Matthew L. 
Published: July 2004

AbstractSoap, in the strictest terms, is defined as the alkali salt of fatty acid. In industrial terminology, soap usually refers to the subset of monocarboxylate salts of at least eight carbons in length. However, in more contemporary vocabulary, soap has come to represent a myriad of commercial products: bar soap, liquid soap, laundry soap, etc, many of which are no longer wholly based on carboxylate salts. This article discusses the chemical and physical properties as well as production of carboxylate soaps, focusing particularly on the use of soap for personal cleansing products.The term soap refers to the group of neutralized long‐chain carboxylic acids and have the general chemical form\documentclass{article}\pagestyle{empty}\begin{document}${CH_{3}\left({{\rm{CH}}{_{2n}}{\rm{COO}}{^{-}}{\rm{M}}{^{+}} }\right)}$\end{document}, where\documentclass{article}\pagestyle{empty}\begin{document}${{\rm{M}}{^{+}}}$\end{document}represents a cation such as sodium. The chain length of the aliphatic group is typically between seven and 21 carbons with one carboxylate carbon, yielding a molecule containing between eight and 22 carbons. The cation associated with the head group is generally sodium or potassium; however, other counterions can also be utilized, such as triethanolamine, heavy metals, alkali‐earth, or other alkali metals, such as magnesium or lithium. Sodium dodecanoate, CH3(CH2)10COONa, commonly named sodium laurate, is a good example of a simple soap.
Sodium Chloride
Authors: Bertram Bruce M. 
Published: July 2004

AbstractSodium chloride or common salt is produced by the mechanical evaporation of solution‐mined brine, solar evaporation of seawater or natural brines, and the underground mining of the mineral halite. Salt deposits are widely distributed in nature as bedded deposits and salt structures or diapirs (salt domes). Sodium chloride has physical and chemical properties that make it useful for many purposes, including cooking and food processing, highway deicing, water treatment, animal nutrition, chemical production, and industrial processing. Salt is a low priced, bulk commodity varying in purity depending on the method of production. The United States and China are the world's two leading salt producers.Salt, an essential mineral nutrient, provides the principal cation in plasma and body tissue fluids. Table salt is the principal carrier for iodine to prevent iodine deficiency. The relationship between sodium and high blood pressure is of concern. Salt is regarded as safe for use as a food additive.
Sodium Nitrite
Authors: Bortle Walter H. 
Published: July 2004

Abstract

Sodium nitrite, NaNO
2
, is a versatile industrial chemical having applications that are widely based on its oxidizing properties or its ability to yield nitrous acid on acidification. It is hygroscopic and quite soluble in water, but not in most organic solvents. Sodium nitrite is a moderately strong oxidizer and toxic by ingestion. It can react violently with some chemicals, evolves toxic NO

x

on decomposition, and can promote burning when exposed to fire. It may be derived from the reduction of sodium nitrate, but is typically manufactured by the absorption of nitrogen oxides into solutions of sodium hydroxide or sodium carbonate. Dry and liquid forms of the product in several grades are offered in bulk and a variety of packaging options. Dry products may be treated with an anticake. Typical assays are 99% NaNO
2
for dry and 42% NaNO
2
for liquid products. Sodium nitrite consumed domestically is primarily of U.S. origin, with some imports. The product is used in azo dyes, rubber chemicals, heat treating and heat‐transfer salts, meat curing, metal finishing, organic chemical syntheses, and as a corrosion inhibitor.
Sodium Sulfides
Authors: Bush David R. 
Published: July 2004

Abstract
Sodium hydrosulfide, sodium sulfide, and sodium tetrasulfide are somewhat interchangeable in many applications. Uses range from ore flotation to leather tanning and from pulp processing in kraft pulping to lubricant manufacture. The processes used to manufacture these compounds are described. Sulfide solubilities are discussed. U.S. production and prices for selected years are presented.
Sodium Nitrate
Authors: Pokorny Ludwik , Maturana Ignacio 
Published: July 2004

AbstractMore than 85% of worldwide sodium nitrate production is supplied from natural deposits in Chile, South America; the rest is provided essentially as a by‐product from nitric acid plants. Sodium nitrate is used as a fertilizer and in a number of industrial applications, primarily as an oxidizing agent. These latter include the manufacture of glass, explosives, and charcoal briquettes, and the production of potassium compounds. Consumption of sodium nitrate for industrial uses has been rather steady, but production for use as fertilizer has declined. Various technical and industrial grades are available, in addition to the agricultural grade. Surface mining methods are used to mine the Chilean nitrate ore. Mineral recovery and processing procedures are described, as are the various purification steps. Synthetically produced sodium nitrate results from absorption of waste nitrous oxide gases in an alkaline solution.
Sodium Carbonate
Authors: Eggeman Tim 
Published: July 2004

AbstractSodium carbonate is a white crystalline solid also known as soda ash. Sodium carbonate deposits and brines exist around the world. It is readily produced from natural deposits and also by synthetic pathways. Production from Trona and the Solvay synthetic process account for the vast majority of current capacity. Annual world production is almost 44 × 106tons.Soda ash is classified as a moderate health hazard. It is an essential ingredient in the production of glass, chemicals, soaps, detergents, pulp, and paper.
Soil Stabilization
Authors: Valentine Donald 
Published: July 2004

AbstractThis article describes two general methods to impart desired water control and physical and mechanical properties to soil profiles by chemical treatments. Chemical grouting is the practice of injecting liquids (chemical grouts) containing organics and/or inorganics that solidify to form strong, water‐impermeable barriers into soil, rock, or concrete. Organic systems containing monomers that can polymerize or soluble polymers that can cross‐link into insoluble gels are most often used grouts. Grouts comprising polyacrylamides and polyurethanes are in common use. Typical applications include construction and repair of buildings, dams, shafts, etc. Chemical soil conditioning is the use of chemical treatments, typically with polymers, to improve the ability of soils to support vegetative growth in large‐scale agriculture, horticulture, and urban applications. Some soil conditioners help create and/or stabilize larger soil aggregates, reducing erosion and improving the efficiency of irrigation water use. Others are used to provide water reservoirs in the soil to facilitate agriculture in drier locations. Still others coat and stabilize soil surfaces against wind and water erosion. Many soil conditioners are similar to the polymeric systems formedin situby chemical grouts. The most commonly used soil conditioners are acrylic polymers, especially copolymers of acrylamide and sodium acrylate.
Solar Energy
Authors: Stokes Robert A. 
Published: July 2004

Abstract
Technology for converting the various forms of solar energy to fuels, electricity, or even valuable chemicals is presented. Commercial interest is increasingly focused on a small number of promising technologies for the supply of conventional transportation fuels and grid‐connected electricity. Five technologies are reviewed focusing on developments in the technology of solar energy conversion and progress toward cost goals which must be achieved in order for solar energy to compete with conventional sources of energy without subsidies. Increased world utilization of solar energy is a certainty in the twenty‐first century. Greater near‐term utilization of solar energy forms depends on cost and the availability of conventional fuels.
Sol–Gel Technology
Authors: Hench Larry L. , Orefice Rodrigo 
Published: July 2004

AbstractThe sol–gel process, which has a potentially high technological value, enables materials having unique structures and properties seldom obtained by other processing methods to be produced. Materials prepared by sol–gel technology are of very high purity and homogeneity, having controlled multiphase microstructures, net‐shape forming, and as‐cast surface features made at lower temperatures than those used for other processes. High purity metal alkoxides are employed as precursors for the synthesis of nanometric entities dispersed in a liquid environment or sol that eventually forms a gel. The nanostructure of the gel can be tailored by controlling the chemical reactions involving the precursors.The steps of sol–gel processes for silica‐ and alumina‐based materials are discussed. Sol–gel technology involves precursor mixing and formation of a colloidal suspension, generally followed by a casting operation in which the low viscosity sol is introduced in molds. Aging provides the required mechanical property for further handling. Following aging, the solvents within the pores are eliminated by drying. A stabilization step is also required to eliminate any residual chemisorbed water. Production of a fully dense body involves a densification step at higher temperatures when the porosity is reduced to zero. Application of the sol–gel process include preparation of porous and dense monoliths, silica and alumina fibers, ceramic thin films, biomedical devices, and organic–inorganic hybrid composites. Many of the materials prepared by sol–gel technology are nanostructed. The majority of these substances are multicomponent. The various compositional possibilities are presented.
Solvent Recovery, Condensation
Authors: Frank Otto 
Published: July 2004

Abstract

It had been noted in the previous edition of this
Encyclopedia
, that removing solvents by condensing them from an inert gas in a water‐cooled condenser is inefficient, and may create a potentially hazardous condition at the point of discharge. Vapor pressures of most solvents are relatively high. Therefore, at temperatures obtainable in a water‐cooled heat exchanger these substances maintain an appreciable partial pressure in the discharging gas. An environmentally unacceptable high VOC (volatile organic compound) level in the emitted gas, and the fact that the remaining solvent concentration is in many cases above the lower explosive limit, makes a water‐cooled heat exchanger an unlikely instrument for solvent recovery.
Sonochemistry
Authors: Suslick Kenneth S. 
Published: July 2004

Abstract

Ultrasonic irradiation of liquids causes high energy chemical reactions to occur, often with the emission of light. The origin of sonochemistry and sonoluminescence is acoustic cavitation: the formation, growth, and implosive collapse of bubbles in liquids irradiated with high intensity sound. The collapse of bubbles caused by cavitation produces intense local heating and high pressures, with very short lifetimes. In clouds of cavitating bubbles, these hot‐spots have equivalent temperatures of roughly 5000 K, pressures of about 1000 atmospheres, and heating and cooling rates above 10
10
K/s. In single‐bubble cavitation, conditions may be even more extreme. Thus, cavitation can create extraordinary physical and chemical conditions in otherwise cold liquids.

Sonochemistry can be roughly divided into categories based on the nature of the cavitation event: homogeneous sonochemistry of liquids, heterogeneous sonochemistry of liquid–liquid or liquid–solid systems, and sonocatalysis (which overlaps the first two). In some cases, ultrasonic irradiation can increase reactivity by nearly a million‐fold. Because cavitation can only occur in liquids, chemical reactions are not generally seen in the ultrasonic irradiation of solids or solid‐gas systems.
Sonoluminescence in general may be considered a special case of homogeneous sonochemistry; however, recent discoveries in this field have heightened interest in the phenomenon in and by itself. Under conditions where an isolated, single bubble undergoes cavitation, recent studies on the duration of the sonoluminescence flash suggest that a shock wave may be created within the collapsing bubble, with the capacity to generate truly enormous temperatures and pressures within the gas.
Water, Sources and Quality Issues
Authors: Hem John D. 
Published: July 2004

AbstractFactors affecting stream quality and general principles of stream water geochemistry are given. Ideally, water is controlled by the alteration of rock minerals through chemical weathering processes, which liberate soluble products. These processes are controlled or influenced by climatic factors, such as rainfall, air temperature, and evaporation associated with biological or biochemical processes. Human activity impacts water quality in an ever increasing manner. Carbon, sulfur, and nitrogen are present in the hydrologic cycle and their increase or decrease is an indication of water quality. The author has studied various drainage basins and water quality of these water supplies. One study, of the Great lakes–upper St. Lawrence River, is given as an example.
Spectroscopy, Optical
Authors: McDowell Robin S. , Kelly James F. 
Published: July 2004

AbstractSpectroscopy, the study of electromagnetic radiation and its interaction with matter as a function of frequency or wavelength, is a versatile and powerful tool for investigating atomic and molecular structure, as well as for qualitative and quantitative analysis. Optical spectroscopy is surveyed emphasizing its applicability for qualitative and quantitative laboratory and process analysis and for monitoring atmospheric pollutants. Absorption, emission (from excited samples, and radiometry of ambient thermal emission), scattering (elastic and Raman), and luminescence (fluorescence and phosphorescence) spectroscopies are discussed for the different regions of the electromagnetic spectrum: radio and microwaves, mid‐ and near‐infrared, molecular ultraviolet–visible absorption, atomic absorption and emission, and x‐ray and gamma‐ray, in each case discussing instrumentation, sampling, and applications. Special techniques covered include null‐background detection, nonlinear Raman spectroscopy and other laser‐induced processes, optical activity, and Mössbauer spectroscopy. Modern ultrasensitive spectroscopies being developed for analytical use are briefly reviewed.
Sugar, Special Sugars
Authors: White J. S. 
Published: July 2004

Abstract
Although commercially sucrose is the most important sugar, there are other special sugars with special applications, among which fructose is the most important. Fructose, a monosaccharide consisting of one‐half of the sucrose molecule but having a sweetness 1.3–1.8 times that of sucrose, constitutes 4–8 wt % of many fruits, where it primarily occurs with glucose (dextrose) and sucrose. Maltose (malt sugar) is a disaccharide comprising two molecules of glucose. Although occurring in some plants and fruits, it is more frequently recognized as a structural component of starch. Lactose (milk sugar) is the only commercially available sugar that is derived from animal rather than plant sources. It is a disaccharide consisting of one galactose and one glucose moiety and has only one‐fifth the sweetening power of sucrose.
Sprays
Authors: Mao Chien‐Pei , Tate Roger 
Published: July 2004

AbstractSprays are widely used in many industrial processes. In more recent years, the subject of liquid atomization has developed from a position of minor importance into a broad and significant technology. This article summarizes nonproprietary information and covers such topics as liquid atomizers, physics of atomization, spray characterization, instrumentation, and industrial applications.Atomizers have been summarized according to their sources of energy, distinct design features, and applications. Discussion of the physics of atomization is divided into three different regimes: internal flow, liquid breakup, and droplet dispersion. Spray characterization focuses on the explanation of common spray parameters, typical spray dynamic structures, effect of variables, and correlation techniques. Because of its important role, spray instrumentation is also discussed, along with an overview of representative optical and nonoptical techniques. Specific examples of industrial spray applications are cited and general comments are made regarding the proper selection of liquid atomizers and concerns related to their operation.
Fine Chemicals, Standards
Authors: Tuthill Samuel M. , Jamieson Norman C. 
Published: July 2004

Abstract

Standard setting in the United States for fine chemicals used as drugs, food additives, laboratory reagents, and in the processing of semiconductors is described, as are reference materials for use in analytical procedures. The specifications and methods of test which comprise the standards are published on a regular basis, with interim supplements as necessary, in the
United States Pharmacopeia (USP)‐National Formulary (NF), the Food Chemicals Codex, Reagent Chemicals‐ACS Specifications
, and the
Book of SEMI Standards
. Many test methods, especially those in the USP and NF, require reference standards, available from the USP and the National Institute of Standards and Technology (NIST). The legal status of the USP, NF, FCC, and ACS Standards is discussed, as well as the impact on fine chemicals of the Federal Food, Drug, and Cosmetic Act requirements for Good Manufacturing Practice.