bluuebunny/crossref_metadata_2025 huggingface dataset:
Extraterrestrial Materials
Authors: Brownlee Donald E.
Published: July 2004

Extraterrestrial materials include meteorites that fall naturally to the Earth, as well as samples such as the Apollo and Luna collections collectedin situand returned to Earth by spacecraft. The samples contain highly detailed records of the conditions, processes, and materials that formed them, and these records can be studied in the laboratory with a wide array of modern analytical techniques. Meteorites are typically hand‐sized specimens that are samples of asteroids, small relict planetismals that originally escaped incorporation into planets and contain preserved materials dating back to the earliest history of the solar system. Meteorites are complex assemblages of a variety of components, and among the most exotic of these are interstellar grains that are older than the Sun and planets. Interplanetary dust particles are essentially submillimeter‐size meteorites that contain materials from comets as well as asteroids. Like the asteroids, the comets are also planetismals, but they formed beyond Saturn, whereas most of the asteroids formed between Mars and Jupiter.
Extractive Metallurgy
Authors: Duby Paul
Published: July 2004

Extractive metallurgy which involves chemical production of metals from their naturally occurring compounds, follows mining of the ore, and the processing of the minerals. The essential extractive process, the reduction of a metallic compound to the metal, is often preceded by preparatory steps and followed by a refining one to achieve suitable properties.

Pyrometallurgy, processing at high temperature, often yields a molten metal, but may produce a vapor or a solid. Refining is the removal of impurities by volatilization, precipitation, or by transfer into a molten slag phase as in steelmaking. Hydrometallurgy, processing through an aqueous solution, consists of leaching, purification of the pregnant solution, and recovery of the valuable metal by reduction or precipitation of one of its compounds. Electrometallurgy is the use of electrical energy for reducing the metal either from an aqueous electrolyte or from a high temperature melt. Examples are given for all processes.
Nonwoven Fabrics, Spunbonded
Authors: Smorada Ronald L.
Published: July 2004

Spunbonded fabrics are distinguished from other nonwovens by the integration of fiber spinning, web formation, and bonding during manufacture. Spunbonding is an especially efficient method of manufacturing lightweight fabrics, although the sophisticated manufacturing equipment requires significant capital investment. The thermoplastic polymers, polypropylene, polyester, and polyethylene, provide the material base for most of the fabrics produced. Spinning is accomplished by extruding fibers from either multiple spinnetette banks or a wide rectilinear spinnerette onto a rapidly moving porous belt. Fibers deposited onto the belt form an unbonded web that then passes through a bonder, typically thermal in nature. This process bonds some of the fibers to neighboring fibers, thus providing integrity to the sheet structure. Spunbonded fabrics are produced at widths of 3 m or more in order to facilitate productivity. The high speed manufacture of wide‐width, lightweight fabrics of uniform appearance and properties presents many technical problems. The loss of fiber output from just one of the spinnerettes can cause defects which reduce the usable width of the fabrics. The directionality of the fibers within the fabrics can be controlled during the web‐forming process. This action permits specific physical properties to be engineered into the fabric, although the majority of spunbonded fabrics are, by design, quite isotropic in character. Spunbonded fabrics are used in many applications, including diaper coverstock, interlinings, wipes, furniture construction, geotextiles, carpet backing, mailing envelopes, and filtration. Spunbonded fabrics are routinely used as components in complex structures that utilize their unique physical properties. The enormous growth of spunbonded fabric sales since the 1960s is indicative of their usefulness.
Fans and Blowers
Authors: Monroe Robert C.
Published: July 2004

The engineering and application aspects of centrifugal blowers, ie, high pressure, low volume air delivery, and axial fans, low pressure, high volume air delivery are presented. The types of centrifugal blowers and their uses, typical installation practice, noise, and performance is discussed. Performance curves are defined. Air delivery is effected by blade designs as well as application, especially in the petrochemical field, is detailed including selection, noise prediction, and fan vibration problems. Various means of air flow control from damper, controllable pitch fans to variable speed drives are discussed, and a list of primary U.S. and world manufacturers is given.
Fats and Fatty Oils
Authors: Hasenhuettl G. L.
Published: July 2004

Fats and oils from animal and vegetable sources are primarily triglycerides, ie, esters of glycerol and fatty acids; some are waxes, esters of fatty acids and long‐chain aliphatic alcohols. The composition, production, properties, and uses of fats and fatty oils are discussed. Processing, including degumming, dewaxing, refining, hydrogenation, bleaching, deodorization, rendering, pressing, and solvent extraction, is covered.
Carboxylic Acids, Fatty Acids from Tall Oil
Authors: Johnson Robert W. , Cantrell Robert R.
Published: July 2004

Tall oil fatty acids (TOFA) consist primarily of oleic and linoleic acids and are obtained by the distillation of crude tall oil. Crude tall oil, a by‐product of the kraft pulping process, is a mixture of fatty acids, rosin acids, and unsaponifiables. These components are separated from one another by a series of distillations. Several grades of TOFA are available depending on rosin, unsaponifiable content, color, and color stability. Typical compositions of tall oil fatty acid products are shown.

Tall oil fatty acids have a variety of applications. The largest uses of TOFA traditionally have been in coatings, primarily alkyd resins where grades of higher rosin content predominate. Since the 1970s their use as chemical intermediates in applications, which includes manufacture of dimer acids and epoxidized TOFA esters, has exceeded their use in coatings. The more highly refined, low rosin grades are required for their application as intermediates. Other areas of significant use are in soaps, detergents, and ore flotation. Worldwide crude tall oil fractionating capacity and domestic production and prices of TOFA are given. TOFA pricing is strongly dependent on soya fatty acid prices since these materials are often used in the same application.
Fermentation
Authors: Junker Beth
Published: July 2004

Fermentation processes, products, and economic aspects are summarized according to the product classes of primary metabolites, secondary metabolites, biomass, enzymes (and whole cell biocatalysts), and biologicals. Although the information is focused on aerobic stirred tank processes, anaerobic, bubble column, and/or immobilized production techniques are referenced where applicable. Advantages of biochemical production over strictly synthetic processes are discussed. The history of fermentation is described at time periods of pre‐1700s, 1700s–1900, 1900–1945, 1945–1960, 1960–1970, 1970–1995, and 1995 to the present. This progression is followed by an overview of microbiological and fermentation principles, equipment requirements, inoculum development and scale‐up techniques, utilities, and regulatory considerations. Throughout this article specific product and process examples are included.
Ferrites
Authors: Kools Frans , van der Valk P. J.
Published: July 2004

Two main groups of commercial ferrites are emphasized; the soft magnetic spinel ferrites having as the most important representatives MnZn‐, NiZn‐, and MgZn‐ferrites; and the hard magnetic hexagonalM‐type ferrites having as the main representatives BaM‐ and SrM‐ferrites. These materials are primarily ceramics. The cubic spinel and the hexagonalM‐type crystal structures produce differing magnetic and electrical properties, which result from electron configurations and mutual interactions of the constituent ions. Properties can be optimized for specific applications in the areas of consumer electronics, telecommunication, power conversion, and the automotive industry. Optimum ceramic processing, often including microstructural engineering, is required to obtain fine‐tunings of the various parameters for ferrite applications.
Fertilizers
Authors: Hoffmeister George
Published: July 2004

Fertilizers, classified according to grades reflecting quantities of the three primary plant nutrients, are usually nitrogen, phosphorus, or potassium based. The main function of chemical fertilizers is to supply one or more of these primary nutrients in chemical forms that can be assimilated through plant roots. One or more of the secondary nutrients, calcium, magnesium, or sulfur, or a variety of micronutrients may also be present. Mixed fertilizers are also available. Application is generally through the soil and must be in a chemical form assimilable by the particular crop. Gaseous, liquid, or solid materials may be used. Manufacturing processes for the various physical forms are described.

The nitrogen in chemical fertilizers is derived almost entirely from synthetic ammonia. The phosphorus is derived from extensive mineral deposits, mostly by processes that involve beneficiation of the ore followed by solubilization in sulfuric acid. The potassium sources for fertilizers are salt deposits and brine lakes or wells. Anhydrous ammonia is the most economical nitrogen‐based fertilizer in the United States. Urea is also very popular.
Polyamides, Fibers
Authors: Anton Anthony
Published: July 2004

Polyamide fibers are melt‐spun from linear thermoplastic polymers having recurring amide groups made from diamines and dicarboxylic acids or lactams. Polymer made by the polycondensation of hexamethylenediamine and adipic acid is designated nylon‐6,6; that made from ε‐caprolactam, nylon‐6. These polymers account for about 98% of the total 3.9 million tons of worldwide production of nylon fiber. The attributes of nylon fiber, such as high strength, durability, abrasion resistance, resilience, ease of dyeability, and low specific gravity, have been recognized since its introduction in 1938. Both the inherent properties and those properties that can be engineered into the fiber through manufacturing and ultimately into the fabric article in downstream mill processing account for the diverse end uses of nylon. These include hosiery, lingerie, skiwear, activewear, swimwear, carpets, tire cord, luggage, upholstery, automotive air bags, interliners, and military uniforms.

Nylon fiber is manufactured by extruding molten polymer through a filter pack multihole spinneret assembly and then drawing (or stretching) the filaments as a separate or continuous process to fix the size and physical properties (tenacity, elongation modulus) of the filaments (or yarn) for a particular end use. The product is offered as continuous flat yarn or, through additional manufacturing steps, as crimped staple, tow, or precision‐cut flock. Continuous‐filament (flat) yarn can be used as is, or, for most applications, textured for bulk and/or stretch. Physical appearance, functionality, and performance of nylon filaments can be modified by incorporating additives, eg, delusterants, colorants, antioxidants, and antistats, in the polymer or directly to the melt stream prior to extrusion, by designing a spinneret hole to impart a desired luster or surface effect or by spinning bicomponent or biconstituent fibers. Very fine fibers (0.2 dtex = 0.18 den), are made by spinning biconstituent conjugate fibers with nylon and polyester and dissolving the polyester in an alkali fabric treatment. The introduction of direct melt‐spun 0.88–2.22‐dtex (0.8–2.0 den) nylon products in the mid‐ to late‐1980s had a significant positive effect on the apparel market. Other breakthrough technologies, such as high speed spinning of partially oriented yarns for draw texturing, nylon‐4,6 for industrial yarn applications, soil‐ and stain‐resistant nylon carpets, utilization of available 47–93‐tex (420–840‐den) industrial yarns for an emerging automotive air bag industry, have all contributed to the growth of nylon fibers since the 1980s.

The commitment made by the textile industry to recycle fibers and fabrics and to conserve materials and minimize landfilling in compliance to regulatory legislation will have a profound effect on how fiber producers design their offerings for the future.
Fiber Optics
Authors: Kosinski Sandra , MacChesney John B. , Udd Eric
Published: July 2004

Fiber‐optic based communication depends on the availability of high quality low loss optical fibers. Light guidance within a fiber is discussed.

Operating wavelengths have been extended by controlling fiber attenuation and dispersion. Fiber fabrication methods are presented. The use of high purity starting materials and vapor deposition techniques allows the production of glass fibers having optical losses that approach the intrinsic loss of silica. Fiber drawing processes determine strength. Active optical fibers have been exploited to amplify light, extending the range of transmission systems and allowing increased capacity. Erbium‐doped fibers are being used for signal amplification in fiber‐optic cable. Devices taking advantage of gratings written in optical fibers include filters and lasers.

Most fiber‐optic smart structure applications fall into one of four major categories. The first is smart manufacturing where fiber‐optic sensors are embedded or attached to parts during the manufacturing process. They are then used to monitor such parameters as temperature, pressure, viscosity, degree of cure, and residual strain. After the parts have been made, the same sensors or another set may be used for the second application area of nondestructive testing. Here, the fiber sensors may be used to measure acoustic signatures, changes in strain profiles, delamination, and other indications of changes in the structural characteristics of fabricated parts. The third aspect of fiber‐optic smart structures that has been the focus of many efforts is health and damage assessment systems for structures. In the parts of the structure that have been assembled, fiber‐optic sensor technology is used to monitor the overall health of the structure. Finally, fiber‐optic smart structures may be used to support control systems.

Fiber‐optic sensors that are particularly useful for smart structures are briefly overviewed, followed by examples of applications.
Thin Films, Film Formation Techniques
Authors: Mattox Donald M.
Published: July 2004

A thin film is a surface layer at most a few micrometers thick, having properties that differ from those of the bulk material or substrate on which the film is deposited. Thin‐film formation techniques are often called vapor deposition processes. A variety of techniques are available, which may be classified as either physical vapor deposition or chemical vapor deposition, depending on the source of the vapor to be deposited. Physical vapor deposition processes are the largest‐volume techniques for thin‐film formation. To produce the vapor, vacuum technology, ion plating or atomic sputtering, plasmas, and magnetrons, alone or in some combination, may be used. Chemical vapor deposition involves a chemical reaction. The vapor may come from a gas, liquid, or solid. Electroplating and electroless plating are two chemical deposition techniques that do not involve vapors.
Filtration
Authors: Chase George G. , Mayer Ernest
Published: July 2004

This article gives an overview of liquid filtration. Cake filtration is the most commonly used filtration in industry to separate solid particles from liquid streams. Depth filters are often used in a posttreatment step to polish liquids and remove particles to achieve a specific liquid purity. Brief descriptions are given on cake filtration and depth filtration theories along with a discussion on pretreatment of the slurry and posttreatment of the filter cake.

The theories described in this paper are useful to interpret experimental data and can help guide in the selection of equipment. The remainder of the article focuses on equipment types, equipment selection, and selected testing methods. There are many types of equipment for separating solids from liquid steams. Selection of the most appropriate equipment for a specific application can be difficult. Some guides are provided that help to narrow down the selection process.
Flame Retardants for Textiles
Authors: Calamari Timothy A. , Harper Robert J.
Published: July 2004

This article reviews the treatment of textiles with chemical finishes to provide protection from fire. It traces the history of fire‐retardant chemistry from early work up to the most recent (ca 1993) developments in this area. Details of selected fire‐retardant finishes are presented both for natural fibers, ie, cotton and wool, and for synthetic fibers, ie, polyester and nylon. Essentials of the presently accepted theories of fire retardants and of the burning process are outlined. Specific finishes, test methods, and methods of application are discussed. A review of published work in this area as well as an estimate of the current status of the flame‐retardant industry are provided.
Flavors
Authors: Fischetti Frank
Published: July 2004

Flavoring materials are often classified as condiments, ie, materials used to give relish to foods and gratify the taste. The function and acceptability of flavors, as well as the role of taste and odor in flavor, is discussed here. Natural, artificial, and synthetic flavoring materials, including basic flavor formulations, are presented. Emphasis is given to the technique of compounding. Also included are sections on enzyme precursors, flavor regulations, sensory evaluations, and economic aspects. Essential oils are often components of flavor; their applications are included. Related articles include Carbonated beverages, Chocolate and cocoa, Essential oils, Food additives, and Food processing.
Flax Fiber
Authors: Akin Danny E.
Published: July 2004

Flax (Linum usitatissimumL.) is a versatile plant that supplies consumers both fiber and seed. The long, strong bast fibers processed for linen are prized for comfort and a distinctive appearance in textiles, while shorter fibers are used in textile blends and for specialty paper, reinforced composites, and a variety of other lower value applications. World production of flax fiber has declined from a few decades ago, but particular countries with a long history of flax, eg, Russia and former Soviet Union countries, China, and Western Europe, still dominate in production and areas cultivated. To extract fibers, flax stems are first retted, which is a microbial process to loosen fibers from nonfibrous tissues. The most widely used practice is dew‐retting, where proper moisture and temperature support colonization and partial degradation of flax stems by indigenous fungi. Low quality and other disadvantages of this practice have prompted research for new retting methods, particularly those using chemicals and cell‐free enzymes. Methods to test fiber properties exist, but uniform standards using objective measurements are needed. Research is being undertaken to develop standards toward a uniform classification system for flax fiber. Linen is ∼2–3% of the textile market, having been replaced some time ago by cotton as the premier natural fiber for textiles. Still, linen continues to maintain a share of the luxury textile market. Potentially, the greatest future for flax fibers could be as cottonized, short fibers for textile blends and as industrial fibers with a range in properties for nonwoven materials and composites.
Flotation
Authors: Yarar Baki
Published: July 2004

Froth flotation is a surface chemistry‐based separations process extensively used in mineral processing, coal desulfurization, and water treatment. Flotation‐based separations transcend the field of mineral technology. The article describes the flotation process, its physicochemical basis, kinetic considerations, chemicals used in its industrial practice, their properties, and specific applications. Flotation machines including well‐ established ones and the more recent flotation columns as well as their arrangement in typical flotation circuit configurations are covered.

Numerous technological applications such as sulfide and nonsulfide ore flotation, water treatment, coal desulfurization, and recycling are highlighted with detailed flow sheets. The physicochemical bases of newer approaches including the gamma flotation process and two‐liquid flotation are elaborated. Potential future applications and environmental aspects are also included.
Fluidization
Authors: Avidan Amos A. , King Desmond F. , Knowlton Ted M. , Pell Mel
Published: July 2004

Fluidization is the art of handling a solid as if it were a fluid. To fluidize solid particles, a gas or a liquid flows up through a particle bed at such a rate as to support the weight of particles via drag force such that the weightless particles are free to move and flow akin to molecules in a liquid. Fluidization by a gas is by far the most commonly used technique, although solids can be fluidized by a liquid, or by a gas and a liquid. Often the gas reacts with the particles as it fluidizes them. Commercially, gas‐fluidized beds are used for a multitude of purposes, from drying solids to burning coal and from making plastics to producing gasoline from heavy oils.

The important properties of particles that relate to fluidization are discussed along with the different regimes that fluidized beds can exhibit. The isothermal nature of fluidized beds and the high rates of heat and mass transfer are discussed. Design of fluidized beds is introduced as are the various pieces of hardware needed. Circulating fluidized beds are also discussed, as is industrial scale up.
Fluid Catalytic Cracking (FCC) Units, Regeneration
Authors: Upson L. L. , Rosser F. S. , Hemler C. L. , Palmas P. , Bell L. E. , Reagan W. J. , Hedrick B. W.
Published: July 2004

The fluid catalytic cracking (FCC) process is an important refinery process in the United States. Catalyst regeneration is an essential part of this process. In the reactor section of a FCC unit, hydrocarbon feed is combined with hot fluidizable cracking catalyst at the base of the riser reactor. Catalyst and hydrocarbon vapors pass up the riser in a dilute‐phase, plug‐type flow and discharge into the reactor vessel where catalyst and hydrocarbon vapors are separated. When in contact with the catalyst, the hydrocarbon feed cracks to form gasoline, middle distillates, liquefied petroleum gas (LPG), and fuel gas. Coke, which is also formed, deposits on the catalyst surface and greatly reduces the catalyst activity. To restore its activity, the catalyst passes into the regenerator section where the coke is burned off. The heat released from coke burning is completely used to provide the heat requirements on the reactor side. Heat balance, environmental concerns, regenerator configuration and design, and other parameters of FCC are discussed.
Fluoroethers and Fluoroamines
Authors: Flynn Richard M.
Published: July 2004

Perfluoroaliphatic ethers and tertiary amines are members of a class of unreactive compounds known in the industry as inert fluids. These compounds are prepared by electrochemical fluorination, direct fluorination using elemental fluorine, or cobalt trifluoride fluorination. They are nontoxic, nonflammable, have densities of 1.7–1.9 g/cm
3
, surface tensions of 9–19 mN/m, and lower kinematic viscosities than hydrocarbons. Their thermal stabilities are comparable to the perfluoroalkanes. The low polarizability of these liquids makes them excellent insulators. Their chemical properties are characterized by their extreme unreactivity. Perfluoroaliphatic ethers and amines do not react with most oxidizing or reducing agents nor with strong acids or bases. They are generally poor solvents for most organic compounds, with the exception of highly fluorinated compounds. The lower molecular weight compounds are used in the electronics industry as heat‐transfer fluids, for testing of electronic circuitry, and in vapor‐phase soldering. The higher molecular weight polymers are used as hazardous duty vacuum pump oils, specialty greases, and lubricants.
Fluorinated Higher Carboxylic Acids
Authors: Savu Patricia M.
Published: July 2004

Perfluorinated carboxylic acids are corrosive liquids or solids. The acids are completely ionized in water. The acids are of commercial significance because of their unusual acid strength, chemical stability, high surface activity, and salt solubility characteristics. The higher members of the series have the property of decreasing the surface tension of aqueous solutions well below the point possible with any type of hydrocarbon surfactant. There are five methods for the preparation of long‐chain perfluorinated carboxylic acids and derivatives: electrochemical fluorination, direct fluorination, telomerization of tetrafluoroethylene, oligomerization of hexafluoropropylene oxide, and photooxidation of tetrafluoroethylene and hexafluoropropylene. In general, the reactions of the perfluoroacids are similar to those of the hydrocarbon acids, although in some cases the electronegativity of the perfluoroalkyl groups make formation of certain derivatives easier or harder. A general summary of formation and properties of the derivatives of perfluorinated acids is discussed. Data on the fluorinated dicarboxylic acids and their derivatives are also summarized.
Fluorine
Authors: Shia George
Published: July 2004

Fluorine, the most electronegative element and the strongest known oxidizer, is found in many products that touch our daily lives. the chemical and physical properties of this gas are reviewed. Manufacturing, major applications, and safe handling and use are also discussed.
Fluorine Compounds, Inorganic, Fluorosulfuric Acid
Authors: Evans Francis E. , Mani Ganpat
Published: July 2004

The two most commercially important sulfur‐containing inorganic fluorine compounds are fluorosulfuric acid and sulfur hexafluoride. Fluorosulfuric acid is used as a fluorinating reagent in the preparation of such compounds as boron trifluoride and silicon tetrafluoride, and as a catalyst in organic reactions for alkylation, acylation, polymerization, sulfonation, and isomerization. Fluorosulfuric acid is itself a strong acid. When combined with certain inorganic fluorides, the system exhibits superacid properties. Properties, manufacture, and uses are discussed.

Of the known sulfur fluorides, sulfur hexafluoride and sulfur tetrafluoride are available commercially. Sulfur hexafluoride, nonflammable and of high chemical stability, has a high dielectric, and is used widely in electrical and electronic equipment such as circuit breakers, capacitors, microwave components, etc. Sulfur tetrafluoride is used as a fluorinating reagent. Properties, manufacture, and uses are described. Other sulfur fluorides are discussed.
Foamed Plastics
Authors: Suh Kyung W.
Published: July 2004

This article is concerned with the general theory of expansion, manufacturing processes, properties, and applications of foamed (cellular) plastics. The high strength‐to‐weight ratio, excellent insulating properties, and cushioning properties of cellular plastics have contributed to the development and growth of the broad range of cellular plastics in use. The total usage of foamed plastics in the United States has risen from 441 thousand metric tons in 1967 to 1.6 million metric tons in 1982 and has been projected to rise to about 2.8 million metric tons in 1995.

The manufacturing processes for cellular polymers are described in terms of three classified methods based on the cell growth and stabilization processes. The properties of cellular plastics including mechanical, thermal, electrical, and environmental aging properties, are summarized. A general discussion is given on the properties of cellular plastic necessary in many applications such as the comfort cushioning, thermal insulation, packaging, structural components, buoyancy, electrical insulation, and space‐filling markets. A brief discussion is also given on the process economics, raw materials, and energy considerations for the commercial products of primary importance.
Folic Acid
Authors: Rawalpally Thimma R.
Published: July 2004

L‐Folic acid is a water‐soluble B‐complex vitamin. Folates are a group of compounds which are structurally derived from pteroylglutamic acid or folic acid. Folic acid is a precursor of several important enzyme cofactors required for the synthesis of nucleic acids and in the metabolism of certain amino acids. Folic acid is synthesized only by plants and microorganisms. The neural tube defect may be caused by a deficiency of folic acid. All known commercial syntheses are based on the three component method process developed in the late 1940s. Industrial production of folic acid by genetically engineered microorganisms or extraction from natural sources is not yet economically viable. A brief review of the biosynthesis and the physiological role of folic acid is presented.
Food Processing
Authors: Farkas Daniel F.
Published: July 2004

Food processing includes unit operations and processes for converting plant and animal tissue to edible foods and ingredients. These processes, which can be grouped by raw product preparation, assembly to consumer products, and preservation processes are regulated by federal laws. Food preservation techniques vary according to food and length of storage.

Foods are preserved before or after packaging using combinations of heat, chemical additives and fermentation products, refrigeration or freezing, dehydration, or mechanical methods such as filtration and ultrahigh pressure. Foods sterilized before packaging must be packaged aseptically. Heat sterilization of foods in rigid and flexible packages is also possible. Preservation techniques and the specialized equipment used are described. Process control and optimization are discussed.
Foods, Nonconventional
Authors: Litchfield John H.
Published: July 2004

Nonconventional foods can be produced from chemicals such as carbohydrates, hydrocarbons, and industrial organic chemicals by processes such as microbiological, enzymatic, or chemical synthesis; or from existing natural products containing carbohydrates, proteins, and fats by physical, chemical, microbiological, or enzymatic modification.

Examples of nonconventional foods include single‐cell proteins, eg, dried cells of microorganisms such as algae bacteria, actinomycetes, yeasts, molds, and higher fungi; derived plant and animal products, eg, leaf meals and leaf protein concentrates, and fish and meat protein concentrates and isolates; synthetic products, eg, carbohydrates, fats, proteins, peptides, amino acids, and vitamins prepared by chemical, microbiological, or enzymatic synthesis; and manufactured or combination foods, eg, engineered, restructured, or textured foods.

Nonconventional foods must have nutritional value to humans or animals, and functional value in foods which ensure quality and social and cultural acceptability. They also must meet regulatory agency requirements for safety for human consumption, including freedom from toxic, mutagenic, and carcinogenic substances and pathogenic microorganisms.
Formic Acid
Authors: Drury David J.
Published: July 2004

Formic acid is the simplest of the homologous series of alkyl carboxylic acids. It is a liquid boiling at 101C with an intense pungent smell. It forms hydrogen‐bonded dimers in the gas phase and polymeric chains in the solid state.

Many of the chemical properties of formic acid are broadly similar to those of other aliphatic carboxylic acids, but with the differences commonly found in the first member of a homologous series. It is, for example, a stronger acid than any of the higher homologues. Formic acid can decompose either to CO and H2O or CO2] and H2.

Formic acid is manufactured industrially as a medium‐tonnage commodity (world capacity ca 330,000 t/yr). It is produced by three different processes: from formate salts, by liquid‐phase oxidation of hydrocarbons, and by carbonylation of methanol to give methyl formate, followed by hydrolysis. The last of these is the most important industrially.

Formic acid is shipped in concentrations of 85‐;mt 99%. Appropriate precautions must be followed in shipping and handling of this corrosive material.

In Europe formic acid's largest use is as a silage addition whereas in the United States this application scarcely exists, and formic acid's main U.S. markets are in the textile and rubber industries and as a chemical intermediate.
Formaldehyde
Authors: Gerberich H. Robert , Seaman George C.
Published: July 2004

Formaldehyde is a versatile, reactive substance, basic to the chemical industry because of its low cost and ease of production. It is manufactured by vapor‐phase oxidation of methanol using two principal processes. One method employs a pure silver catalyst and the other an iron molybdate catalyst. Several other processes are under development, but none have been commercialized. All processes are capital intensive, requiring integrated reaction, heat recovery, and purification systems to achieve optimum economic benefits.

Formaldehyde is sold as concentrated, aqueous solutions, and may contain methanol to inhibit polymerization. It is also sold in alcohol solutions, which contain little water. Its principal uses are in the production of amino and phenolic resins, polyhydric alcohols, acetal resins, paraformaldehyde, and fertilizers. It reacts with numerous organic compounds in condensation‐type reactions, resulting in formation of one or more new carbon‐carbon bonds.

In recent years, formaldehyde has come under increased scrutiny because of its potential negative health effects. It is an irritant to the eyes, nose, and throat, and is a suspected human carcinogen.
Friedel‐Crafts Reactions
Authors: Olah George A. , Reddy V. Prakash , Prakash G. K. Surya
Published: July 2004

After the initial discovery by Friedel and his American associate, James Mason Crafts, that anhydrous aluminum chloride could be used as a condensing agent in a general synthetic method for furnishing an infinite number of hydrocarbons. They extended their discoveries of the catalytic effect of aluminum chloride in a variety of organic reactions:(1)reactions of alkyl and acyl halides and unsaturated compounds with aromatic and aliphatic hydrocarbons;(2)reactions of acid anhydrides with aromatic hydrocarbons;(3)reactions of oxygen, sulfur, sulfur dioxide, carbon dioxide, and phosgene with aromatic hydrocarbons;(4)cracking of aliphatic and aromatic hydrocarbons; and(5)polymerization of unsaturated hydrocarbons. The diversity of reactions is astounding.

Many important industrial processes such as the production of high octane gasoline, ethylbenzene (eventually leading to polystyrene), synthetic rubber, plastics, and detergent alkylates are based on Friedel‐Crafts chemistry. Friedel‐Crafts‐type reactions are generally considered to be any substitution, isomerization, elimination, cracking, polymerization, or addition reaction that takes place under the catalytic effect of Lewis acid‐type acidic halides (with or without cocatalysts) or Brønsted acids. Friedel‐Crafts reactions can be divided into two general categories: alkylations and acylations. Within these two broad areas there is considerable diversity. Friedel‐Crafts catalysts are electron acceptors, ie, Lewis acids. Catalysts include acid halides (Lewis acids), metal alkyls and alkoxides, protic acids (Brønsted Acids), acidic oxides and sulfides (acidic chalcogenides), acidic cation‐exchange resins, and superacids (Brønsted superacids, super Lewis acids, Brønsted‐Lewis superacids, solid superacids, and superacidic zeolites).
Fungicides, Agricultural
Authors: Dreikorn Barry A. , Owen W. John
Published: July 2004

Pathogenic fungi cause a substantial reduction in expected crop yields; further losses can result during storage of harvested crops. For those fungi that can seriously affect economically important plants, means have been sought to control these infections by crop rotation and husbandry, genetic manipulation of the plant species, and external treatment of plants using agricultural fungicides.

Agricultural fungicide application accounts for about 20% of all pesticide use. Agricultural fungicides can be applied to the soil to control fungi that are resident there, to the seed or foliage of the plant to be protected, or to harvested produce to prevent storage losses. Those applied to the soil are in many instances nonselective, volatile soil sterilants, such as formaldehyde, which kill all soil organisms, including fungi. Seed and foliar‐applied agricultural fungicides, are discussed also. Fungicides are classified herein as being nonsystemic or systemic. The nonsystemic fungicides have a protectant mode of action and must be applied to the surface of a plant generally before infection takes place. These do not translocate from the site of application. The systemic fungicides can penetrate the seed or plant and are then redistributed within to unsprayed parts or subsequent new growth, rendering protection from fungal attack or eradicating a fungus already present. Well over 100 plant pathogens have become resistant to various fungicides under field conditions. Failure of the acyl alanines, benzimidazoles, thiophanates, carboxanilides, dicarboximides, hydroxypyrimidines, some organophosphates, and most of the antibiotics has occurred. In other cases, a moderate decrease in sensitivity without a rapid loss of disease control has been observed as in the case of sterol biosynthesis inhibitors and organophosphates. The most effective approach is to use fungicides having different modes of action in combination, either as mixtures or in alternation, possibly utilizing both specific site and multisite inhibitors. Because of resistance problems great importance is attached to chemistries that inhibit novel fungal enzyme targets.

Newer fungicides, in order to retain cost‐effectiveness, need to be very highly active, which also serves to achieve efficacy in the field at low dose rates thus keeping environmental pollution problems as small as possible. Recombinant DNA technologies are expected to play an escalating role in the validation of such biorational targets.
Furnaces, Fuel‐Fired
Authors: Bozzuto Carl R.
Published: July 2004

A furnace is a device (enclosure) for generating controlled heat with the objective of performing work. In fossil‐fuel furnaces, the work application may be direct (eg, rotary kilns) or indirect (eg, plants for electric power generation). The furnace chamber is either cooled (waterwall enclosure) or not cooled (refractory lining). Furnaces related to metallurgy such as blast furnaces are excluded. Fuel‐fired furnaces primarily utilize carbonaceous or hydrocarbon fuels. Since the purpose of a furnace is to generate heat for some useful application, flame temperature and heat transfer are important aspects of furnace design. Industrial furnaces are an order of magnitude smaller than power‐plant furnaces since the applications are usually on an individual basis rather than feeding power to a regional electric grid. Like the power‐plant furnace, the function of the industrial furnace usually is to generate steam, generally for a chemical process, mechanical power, or heating application, rather than electric power generation. New furnace concepts in evolutionary stages include fluidized‐bed furnaces, coal gasification furnaces, and MHD furnaces. Fluidized‐bed combustion has reached commercial‐scale operations.
Helium Group Gases
Authors: Hwang Shuen‐cheng , Weltmer William R.
Published: July 2004

The helium‐group gases are characterized by completely filled valence electron shells. Helium, argon, and neon are commercially available, but krypton, xenon, and radon are quite rare. Principal uses of commercial helium include those as a lifting gas, as an inert carrier gas, and as a cryogenic refrigerant. Helium‐3 and helium‐4, which are both stable isotopes used in cryogenics, differ significantly in their liquid properties because of quantum mechanical effects. Argon finds use principally as an inert gas in industries ranging from electronic ones to steelmaking. Neon is employed as a filling gas in detection chambers and in light sources from commercial signs to lasers.Sources and properties of these gases are discussed. Production of helium from natural gas, and of argon and neon from air separation plants, is presented.
Fuels, Synthetic, Gaseous Fuels
Authors: Speight James G.
Published: July 2004

FUELS, SYNTHETIC, GASEOUS FUELS.Whereas coal continues to be a principal source of substitute natural gas, a more recently recognized source is petroleum. Coal can be converted to gas by several routes, but often a particular process is a combination of options chosen on the basis of the product desired, ie, low, medium, or high heat‐value gas. Coal gas is the term applied to the mixture of gaseous constituents that are produced during the thermal decomposition of coal at temperatures in excess of 500°C, often in the absence of oxygen (air). A solid residue (coke, char), tars, and other liquids are also produced in the process.

Next to combustion, carbonization represents one of the largest uses of coal. Carbonization is essentially a process for the reproduction of a carbonaceous residue by thermal decomposition, accompanied by simultaneous removal of distillate, of organic substances. This process may also be referred to as destructive distillation. The gasification of coal is essentially the conversion of coal by any one of a variety of processes to produce combustible gases.
Gasoline and Other Motor Fuels
Authors: Hochhauser Albert M.
Published: July 2004

Gasoline and Other Motor Fuels. Albert M. Hochhauser (Exxon Research and Engineering Co.). Gasoline and other motor fuels comprise the largest single use of energy in the U.S. The cost of this energy continues to be a primary factor in the national economy. The fraction of resources from which these fuels come that is provided by foreign sources is a matter of political concern. Rapid increases in the price of crude oil has led to programs for developing alternative sources of fuels such as coal, oil shale, and natural gas. Alternative fuels are more important for the potential to reduce emissions and improve air quality than for energy self‐sufficiency.

All motor fuels in the U.S. are manufactured by private companies. Many participate in other aspects such as refining or marketing. Gasoline demand is determined by the numbers of cars, paved roads, population, and economic growth. Predictions for future demand are somewhat divided. Gasoline must meet exacting specifications and vary according to location, temperature and altitudes at which the product is used. Octane is probably the single most recognized measure of gasoline quality. Petroleum refining begins with distillation of crude oil into many fractions. Most gasoline in the U.S. is obtained by catalytic cracking. Reforming increases octane. Gasoline additives (e.g., dyes, antioxidants, detergents, etc.) are used to improve performance. Stricter emission standards have resulted in changes in vehicle hardware. Diesel fuel, second to gasoline, is used in a wide variety of engines. The ability of diesel fuel to burn properly is described by its cetene number. Diesel manufacturers have found it difficult to meet emission standards Alternative fuels include those made from coal and shale, methanol, compressed natural gas and liquefied petroleum gas. Use of alternative fuels has been promoted for two reasons: potential emissions benefits and reduced dependence on imported petroleum.
Gastrointestinal Agents
Authors: Jacoby Henry I.
Published: July 2004

The primary aim in antiulcer therapy is either prevention of acid secretion from the gastric parietal cells or neutralization of the acid before it comes into contact with the ulcerated areas of the gastrointestinal tract. Long established therapy of duodenal ulcers, included diet, antacids, and anticholinergics. Of these, only antacids have been shown conclusively to be effective. The antacids can produce healing, but only when given in large and frequent doses. Antacids include aluminum hydroxide gel, precipitated calcium carbonate, magnesia and alumina suspension, magnesium oxide, magnesium trisilicate, magaldrate, and sodium bicarbonate.

The therapy for duodenal ulcers changed drastically upon the introduction of cimetidine (an H2blocker) in the United States in 1977. Omeprazole is a potent antisecretory agent and is used only for acute therapy of ulcerative disease and esophagitis.

Drugs acting by mechanisms not related to inhibition of gastric acid secretion have been introduced into therapy in the United States. Sucralfate, misoprostil Therapy also has been changed by the acceptance thatHelicobacter pylori, an organism able to withstand the acid media of the stomach, is associated with gastritis and ulcerative disease.

Laxatives facilitate the passage and elimination of feces. Laxatives have traditionally been classified as bulking agents; contact, ie, stimulant; saline, ie, osmotic; and emollients, ie, lubricant.

Commonly used antidiarrheals work by one of two mechanisms: effects on net intestinal secretion, or a decrease in intestinal propulsive motility.

Antiemeticsmay act at a variety of physiological locations, eg, blockade of dopamine and effects at the chemoreceptor trigger zone, vestibular apparatus, or serotonin (5‐HT3) receptors. Gastric prokinetics are a new class of agent that can augment gastric emptying.
Gelatin
Authors: Keenan Thomas R.
Published: July 2004

The general subject, gelatin, is reviewed. Topics include the chemical composition and structure, physical and chemical properties, manufacturing methods, quality standards, analytical methods, and economic aspects.
Gemstone Materials
Authors: Nassau Kurt
Published: July 2004

There are three types of gemstone materials as defined by the U.S. Federal Trade Commission: natural gemstones are found in nature and at most are enhanced; imitation or simulated, fake, faux, etc, material resembles the natural material in appearance only and is frequently only colored glass or even plastic; and synthetic material is the exact duplicate of the natural material, having the same chemical composition, optical properties, etc, as the natural, but made in the laboratory. The word gem cannot be used for synthetic gemstone material. The synthetic equivalent of a natural material may be used as an imitation of another. Synthetic gemstone materials often have multiple uses. Synthetic ruby and colorless sapphire are used for watch bearings, unscratchable watch crystals, and bar‐code reader windows. Synthetic quartz oscillators are used for precision timekeeping, citizen's band radio (CB) crystals, and filters. Synthetic ruby, emerald, and garnets are used for masers and lasers. In the gemstone jewelry market, synthetics provide a less expensive alternative to natural gemstones, but of a better quality than that available in costume jewelry. In general, a synthetic should be available for no more than 10% of the cost of equivalent‐quality natural gemstone to be commercially viable. The important properties are those of importance in natural gemstones. Several gemstone species occur in various colors, depending on the presence of impurities or irradiation‐induced color centers.

The most frequently used techniques for the commercial manufacture of synthetic gemstone materials are based on crystal growth from the meet or crystal growth from solution.