bluuebunny/crossref_metadata_2025_split huggingface dataset:
Expert Systems
Authors: Ramesh T. S. 
Published: July 2004

AbstractExpert systems, or more appropriately knowledge‐based systems, are essentially computer programs that encode the expertise of human problem solvers in some well‐defined domain. A practical offshoot of the field of artificial intelligence, knowledge‐based technology has emerged as an important area of computer applications, with significant business impact on the industry. This is because knowledge‐based systems can automate problem‐solving tasks that hitherto could not be computerized by conventional, numeric modeling techniques. In the domain of chemical engineering, knowledge‐based systems have been used to automate such tasks as equipment and process design, control of complex processes, troubleshooting process operations, scheduling batch processes under uncertain conditions, and simulation of discrete event operations. This article discusses the motivations and benefits of knowledge‐based technology as applied to chemical engineering problems; the differences between knowledge‐based systems and quantitative, numerical techniques; the theoretical underpinnings of the technology; approaches to selecting, designing, and implementing knowledge‐based system applications; and some of the tools available to implement such systems. Alternatives to expert systems such as neural networks (nets) and case‐based reasoning are also briefly discussed. Throughout, the concepts are illustrated using examples from chemical engineering.
Extraterrestrial Materials
Authors: Brownlee Donald E. 
Published: July 2004

AbstractExtraterrestrial 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

AbstractExtractive 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

AbstractSpunbonded 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

Abstract
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

AbstractFats 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

Abstract
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

AbstractFermentation 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

AbstractTwo 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

AbstractFertilizers, 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

AbstractPolyamide 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

AbstractFiber‐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

AbstractA 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

AbstractThis 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

AbstractThis 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

AbstractFlavoring 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

AbstractFlax (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

Abstract
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

Abstract
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.