bluuebunny/crossref_metadata_2025_split huggingface dataset:
Boron Halides
Authors: Alam Fazlul 
Published: August 2004

AbstractThe boron trihalides boron trifluoride, BF3, boron trichloride, BCl3, and boron tribromide, BBr3, are important industrial chemicals having increased usage as Lewis acid catalysts and in chemical vapor deposition (CVD) processes. Boron halides are widely used in the laboratory as catalysts and reagents in numerous types of organic reactions and as starting material for many organoboron and inorganic boron compounds. Reactions of boron trihalides that are of commercial importance are those of BCl3and, to a lesser extent, BBr3, with gases in chemical vapor deposition (CVD). Boron trichloride is prepared on a large scale by the reaction of Cl2and a heated mixture of borax,\documentclass{article}\usepackage{amssymb}\pagestyle{empty}\begin{document}${{\rm{Na}}{_{2}}{\rm{BO}}_{4}{\rm{O}}{_{7}}{\hskip-0.167em}{\hskip-0.167em}{\cdot{}}{\hskip-0.167em}{\hskip-0.167em}10{\rm{H}}{_{2}}{\rm{O}}}$\end{document}, and crude oil residue in a rotary kiln heated to 1038°C. Boron trihalides, BX3, are trigonal planar molecules which are (sp)2hybridized. The X–B–X angles are 120°. The boron trihalides are strong Lewis acids; however, the order of relative acid strengths,\documentclass{article}\usepackage{amssymb}\pagestyle{empty}\begin{document}${{\rm{BI}}{_{3}}\geq {\rm{BBr}}{_{3}}>{\rm{BCl}}{_{3}}>{\rm{BF}}{_{3}}}$\end{document}, is contrary to that expected based on the electronegativities and atomic sizes of the halogen atoms. Boron tribromide is produced on a large scale by the reaction of Br2and granulated B4C at 850–1000°C or by the reaction of HBr with CaB6at high temperatures. Approximately 75–95% of the BCl3consumed in the United States is used to prepare boron filaments by CVD. Another important use of BCl3is as a Friedel‐Crafts catalyst in various polymerization, alkylation, and acylation reactions, and in other organic syntheses. BCl3is also used for the production of halosilanes, in the preparation of many boron compounds and in the production of optical wave guides. Approximately 30% of BBr3produced in the United States is consumed in the manufacture of proprietory pharmaceuticals. BBr3is used in the manufacture of isotopically enriched crystalline boron, as a Friedel‐Crafts catalyst in various polymerization, alkylation, and acylation reactions, and in semiconductor doping and etching. Boron subhalides are binary compounds of boron and the halogens, where the atomic ratio of halogen to boron is less than 3. The boron monohalides and boron dihalide radicals have been studied. Diboron tetraflouride, B2F4, diboron tetrachloride, B2Cl4, diboron tetrabromide, B2Br4, and diborontetraiodide, B2I4, are well‐known but thermally unstable compounds.
Chemometrics
Authors: Illman Deborah 
Published: August 2004

AbstractChemometrics has been defined as the chemical discipline that uses mathematical and statistical methods to design or select optimal measurement procedures and experiments and to provide maximum chemical information by analyzing chemical data. The definition, historical development, salient methods, and illustrative applications of chemometrics are given. Methods of pattern recognition for exploratory data analysis are discussed, including techniques of scaling, feature weighting, principal components analysis, cluster analysis, classification methods, such as linear learning machine, k‐nearest neighbor, and SIMCA, and modeling methods, such as partial least squares path modeling. Methods for multivariate calibration and resolution are discussed including the generalized standard addition method (GSAM) and the self‐modeling curve resolution approach. Methods to optimize experimental performance, including simplex optimization, are outlined. Illustrative examples of the application of chemometrics in forensic chemistry, environmental chemistry, clinical chemistry, sensor design, and industrial process control are presented.
Color
Authors: Nassau Kurt 
Published: August 2004

Abstract

Two theories of color perception have been dominant. The trichromatic theory relates to blue‐, green‐, and red‐sensitive cones in the retina of the eye. It explains various forms of color blindness and is the basis of the CIE chromaticity diagram using
x, y, Y
. The opponent theory uses the opposites light/dark, red/green, and blue/yellow. It explains a variety of perception phenomena and is the basis of color spaces such as CIE
L
*
a
*
b
*. These apparently incompatible approaches apply to different parts of the color perception process. Modern electronic instruments have greatly simplified the measurement of color.

Fifteen distinct chemical and physical mechanisms explain the various causes of color, all involving the behavior of electrons in matter. Vibrations and simple excitations explain the colors produced by incandescence (flames), gas excitation (vapor lamps), and vibrations and rotations (blue of water). Ligand field effects give the colors of transition‐metal compounds and impurities (turquoise and ruby, respectively). Molecular orbitals give the colors in organic compounds (dyes) and charge‐transfer compounds (blue sapphire). Energy bands lead to the colors of metals (copper), semiconductors (vermilion), doped semiconductors (blue diamond), and color centers (amethyst). Geometrical and physical optics explain colors from dispersive refraction (prism spectrum), scattering (blue sky), interference (soap bubble), and diffraction (opal).
Coordination Compounds
Authors: Archer Ronald D. 
Published: August 2004

AbstractThe chemistry of the metallic elements is predominately coordination chemistry. Coordination compounds often have unique properties relative to both the ligands and the metal ions that make up the compound or complex ion. Coordination compounds are used as catalysts both in nature and industry, as bactericides and fungicides, as polymer components and polymer catalysts, as dyes and pigments, in photographic dyes and processing, in electroplating, in petroleum additives, in drugs and artificial blood, as imaging agents, as components of high temperature superconductors, and in a variety of other uses. The metals and ligands combine to provide a wide range of reactivities in substitution and oxidation‐reduction thermal as well as in photochemical processes. Similarly, the stability of coordination species varies widely with different ligands and metals. Whereas this variation is often simplified to hard and soft acid‐base interactions, gradations exist along with steric selectivity. Coordination compounds have a special nomenclature, exist in a wide variety of coordination geometries, and are intepreted in a variety of theoretical considerations.
Corrosion and Corrosion Control
Authors: Moran Patrick J. , Natishan Paul M. 
Published: August 2004

AbstractThe various types of corrosion, its manifestations, origins, and the fundamental mechanisms responsible are discussed. The importance of electrochemical reactions, both in causing and in controlling corrosion phenomena, is emphasized. The influence of environmental factors and metallurgical variables is reviewed and the predominant corrosion modes for technologically significant metal and alloy systems are discussed. Standard electrode potentials, Pourbaix and Evans diagrams, and a Galvanic series may be found. The various methods of corrosion prevention, such as use of corrosion‐resistant materials, cathodic protection, application of coatings, and addition of inhibitors, are also described.
Cotton
Authors: Bertoniere Noelie R. 
Published: August 2004

AbstractThe history of cotton, the use of which predates recorded history, is reviewed. The various varieties and their origins are given. Modern practices related to cultivation and production, fertilizers, pest and insecticides, harvesting, ginning, and greige processing are presented. Current information on the physical properties of the cotton fiber is given. The use of high volume instrumentation (HVI) for fiber property measurements is included. The morphology of the cotton fiber is discussed. Information on the structure and reactivity of cotton includes its chemical structure, crystal structure, pore structure, and availability of hydroxyl groups. Its chemical reactions that produce value added products are summarized. These products include stretch cottons, durable press fabrics, flame retardant fabrics, waterproof cottons, antibacterial cottons, and temperature adaptable fabrics. Overall economic aspects and health and safety factors are also given.
Cryogenics
Authors: Agrawal Rakesh , Rowles Howard C. , Kinard Glenn E. 
Published: August 2004

AbstractBy accepted international standard, “cryogenics” refers to phenomena and processes occurring at or using temperatures below 120 K. Permanent gases, such as oxygen and helium, can be liquefied at ambient pressure at temperatures of 120 K or below.Cryogenic technology has contributed greatly to scientific research and is used in a wide range of industrial applications. Cryogenic condensation and distillation processes are widely used to produce high purity oxygen, argon, nitrogen, hydrogen, and helium for the chemical, metal, and electronic industries. These gases and others, such as natural gas, are commonly stored and shipped as cryogenic liquids rather than as pressurized gases. Cryogenic processes are also used to provide low temperatures to refrigerate, freeze, and store other materials, such as food and biological tissue, or to alter the properties of materials, as with superconductivity.A wide variety of specialized equipment has been developed for cryogenic processes and apparatus, including compressors, expanders, heat exchangers, and distillation columns. Specialized materials have also been developed to insulate cryogenic equipment, transfer lines, storage tanks, and transport vehicles.
Cumene
Authors: Schulz R. C. , Van Opdorp P. J. , Ward D. J. 
Published: August 2004

Abstract
Cumene (isopropyl‐benzene), is the feedstock for the production of phenol and the coproduct acetone in almost all cases, and it is used in minor amounts for other purposes. Physical, chemical, and thermodynamic properties are listed, and pertinent literature sources for the data are given. Methods of manufacture, exclusively by alkylation of benzene with propylene, are discussed, and details of the most prevalent process, which uses a solid phosphoric acid catalyst, are described. Cumene product quality specifications and the typical costs of production are included. Also as part of the economics discussion, the U.S. supply and market price data through April 1992 appear. Several safety and health factors are discussed as are the principal uses of cumene.
Diamond, Natural
Authors: DeVries Robert 
Published: August 2004

Abstract

Naturally occurring diamond is a relatively rare polymorphic form of carbon characterized by a three‐dimensional arrangement of tetrahedrally coordinated carbon atoms. Both natural and synthesized diamond have the highest hardness of all known materials, the highest thermal conductivity at room temperature, a high refractive index and optical dispersion, a low thermal expansion, and a relatively high inertness to chemical attack. This unique combination of properties permits diamond to be foremost in certain applications: as a highly prized gemstone; industrially as an important abrasive material unsurpassed in certain cutting, drilling, sawing, machining, grinding, and polishing operations for many materials; and in electronic and optical applications as a heat sink and window material, respectively. Upstream exploration has sometimes led to the discovery of kimberlite “pipes.” These structures are the principal source of natural diamonds, and there are over 1000 occurrences of them in the world. Only a small number contain a high enough concentration of diamonds to warrant mining. Alluvial diamonds are recovered from streambeds by panning or washing techniques or, more productively, by removal from pockets where the water has concentrated them. High quality gemstones are recovered from ocean deposits off the coast of Africa. A modern method for the separation of crystal from rock uses the emission of light by luminescence of diamond when exposed to x‐rays. The stones are then themselves separated mostly by hand into two main categories, gem and industrial. Besides the single crystals usually implied in a discussion of diamond, the latter also occurs in nature in the form of polycrystalline aggregates. These can be classified into two types, based on origin: carbonado and ballas. Diamond is nominally pure carbon with a
12
C:
13
C ratio of about 99:1. Although other elements are often reported in analyses, only boron, nitrogen, and possibly beryllium are considered to be truly substitutional in the lattice. The classification of diamonds into four types (Ia, Ib, IIa, IIb) is based primarily on the presence or absence of boron and nitrogen and their location in the lattice. Diamond is the hardest material known because of its combination of a three‐dimensional arrangement of tetrahedrally coordinated C–C bonds with a bond distance of 0.154 nm. The Knoop hardness
(K)
is in the range of 68.7–98.1 kN/m
2
(7,000 to 10,000 kgf/mm
2
). Although hard, diamond is also very brittle. The high refractive index (2.42 at 589.3 nm) and dispersion (0.044) are the basis for the brilliance and fire of a properly cut gemstone. The optical transmission out to 10.6 µm for Type IIa diamonds makes possible windows for CO
2
lasers and for devices such as were used in the Venus probe.
Dimensional Analysis
Authors: Chen Wai‐kai 
Published: August 2004

AbstractDimensional analysis provides procedures of judicious grouping of variables associated with a physical phenomenon to form dimensionless products of these variables, so that the equation describing the physical phenomenon may be more easily determined experimentally. The concepts of units and dimensions are introduced. The notions of primary and secondary dimensions, dimensional formulas, and the absolute, gravitational, and engineering systems of dimensions are discussed.Dimensional analysis is based on the premise that any equation that correctly describes a physical phenomenon must be dimensionally homogeneous. To this end, the dimensional matrix is introduced. It is shown that the number of products in a complete set of dimensionless products called the β‐numbers associated with a physical phenomenon is equal to the number of variables that are involved in the phenomenon minus the rank of the associated dimensional matrix. The latter is equal to the maximum number of these variables that will not form a dimensionless product. It states that an equation is dimensionally homogeneous only if it is reducible to a relationship among a complete set of dimensionless products. Finally, a systematic procedure for computing and optimizing a complete set of dimensionless products is described.
Distillation, Azeotropic and Extractive
Authors: Doherty Michael F. , Knapp Jeffrey P. 
Published: August 2004

AbstractMany industrial processes depend on efficient separation methods for azeotropic or other close‐boiling or low relative volatility mixtures. Whereas ordinary distillation is either uneconomical or impossible in these cases, the addition of specially chosen separating agents can generally facilitate the separation. Four of the five principal techniques employed are discussed: extractive or homogeneous azeotropic distillation, where the liquid separating agent is completely miscible; heterogeneous azeotropic distillation, where the agent, known as the entrainer, forms one or more azeotropes but causes immiscibility; distillation in the presence of ionic salts, which alters the relative volatilities of the components; and pressure‐swing distillation, where a series of columns operate at different pressures. Residue curve maps, material balance lines, and column sequences are given for several commercially important systems. Methods for evaluating total annualized costs are also discussed as are models for determining feasible separating agents.
Glycols, Ethylene Glycol and Oligomers
Authors: Forkner M. W. , Robson J. H. , Snellings W. M. 
Published: August 2004

AbstractGlycols are diols, compounds containing two hydroxyl groups attached to separate carbon atoms. In an aliphatic chain, ethylene glycol, is the simplest glycol. Diethylene, triethylene, and tetraethylene glycols are oligomers of ethylene glycol. Polyglycols are higher molecular weight adducts of ethylene oxide and are distinguished by intervening ether linkages in the hydrocarbon chain. These polyglycols are commercially important; their properties are significantly affected by molecular weight. They are water soluble, hygroscopic, and undergo reactions common to the lower weight glycols.The uses for ethylene glycol are numerous. Some of the applications are polyester resins for fiber, PET containers, and film applications; all‐weather automotive antifreeze and coolants, defrosting and deicing aircraft; heat‐transfer solutions for coolants for gas compressors, heating, ventilating, and air‐conditioning systems; water‐based formulations such as adhesives, latex paints, and asphalt emulsions; manufacture of capacitors; and unsaturated polyester resins. The oligomers also have excellent water solubility but are less hygroscopic and have somewhat different solvent properties. The largest commercial use of ethylene glycol is its reaction with dicarboxylic acids to form linear polyesters.The first commercial application of the Lefort direct ethylene oxidation to ethylene oxide followed by hydrolysis of ethylene oxide remains the main commercial source of ethylene glycol production.In addition to oligomers ethylene glycol derivative classes include monoethers, diethers, esters, acetals, and ketals as well as numerous other organic and organometallic molecules.
Nonwoven Fabrics, Spunbonded
Authors: Smorada Ronald 
Published: August 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 banks or a wide rectilinear spinnerette onto a rapidly moving porous belt. Fibers deposited onto the belt form an unbonded web which 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 growth of spunbonded fabric sales since the 1960s is indicative of their usefulness.
Coal Conversion Processes, Liquefaction
Authors: Baldwin Robert M. 
Published: August 2004

AbstractCoal liquefaction involves taking the solid coal to liquid hydrocarbon and oxygenate products. Both direct and indirect routes, the latter being known as the Fischer‐Tropsch process, are known. Direct liquefaction utilizes hydrogenation (hydroliquefaction) or pyrolysis of the coal in a single processing sequence. Indirect liquefaction processes involve the production of synthesis gas, ie, coal gasification, as the first step, followed by catalytic conversion to liquid products.Liquefaction processes that have moved beyond the laboratory are discussed. Flow diagrams, reactor types and conditions, catalytic composition, conversion efficiency, and product make‐up are given.
Lithium and Lithium Compounds
Authors: Kamienski Conrad W. , McDonald Daniel P. , Stark Marshall W. 
Published: August 2004

AbstractLithium, an element of unique physical and chemical properties, is useful in a wide range of applications as the metal, as the lithium ion in inorganic salts, and as the more covalent species in inorganic compounds. The largest uses of lithium compounds are in traditional areas such as the preparation of glass, glass‐ceramics, and enamels; in aluminum cell broth; in the preparation of lithium greases; and as polymerization initiators. Lithium compounds are also employed as psychopharmacological agents and in organic synthesis, catalysis, absorption, air conditioning, photographic processing, and in batteries. Evolving applications include use in fuel cells, electrooptical communications, and as a concrete additive.The various lithium mineral and brine resources are reviewed along with the processes for lithium extraction and recovery. Manufacturing processes, properties, and applications for lithium metal and lithium compounds are discussed.
Nonlinear Optical Materials
Authors: Dalton Larry R. 
Published: August 2004

AbstractNonlinear optical materials are the building blocks of an emerging technology of photonics that uses light to acquire, process, transmit, and store information. These materials perform functions such as modulation, switching, rectification, frequency generation, limiting, and amplification, all of which are typically performed by semiconductors in electronic technology. Nonlinear optical materials and phenomena can be classified as second or third‐order, reflecting the order of electric field interactions involved. Second‐order phenomena are observed only for noncentrosymmetric materials. Such phenomena include electrooptic modulation, spatial light modulation, and second harmonic generation. Electro‐optic modulation may play a critical role in electric‐to‐optical signal transduction and in switching in local area networks. Third‐order phenomena include the dynamic Kerr effect, degenerate four‐wave mixing, third harmonic generation, saturable absorption, reverse saturable absorption, etc. The dynamic Kerr effect can be exploited for all‐optical switching and also for beam focusing, such as in mode‐locking of the Ti:sapphire laser. Reverse saturable absorption can be exploited for sensor protection. Both organic and inorganic materials have been observed to exhibit large optical nonlinearities. Material morphologies ranging from crystalline to polymeric have been considered for nonlinear optical applications; examples of materials are given.