bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microscopy
Authors: McCrone Walter C. 
Published: August 2004

AbstractMicroscopy involves the production and study of magnified images of objects too small to resolve with the unaided eye. There is no single microscope; rather, there are dozens of types, having in common only the ability to present an enlarged image. Microscopes vary in the mechanism by which enlarged images are formed, and in the information presented for each enlarged object. Some microscopes use visible light; others use infrared, ultraviolet, or x‐ray radiation; electrons are also used. There are a variety of scanning microscopes, some of which scan the object with an electron beam, a laser beam, or ultraviolet light. Most recently, an entire family of microscopes have been developed that scan a surface, maintaining a constant, tiny distance from that surface and thus plotting a surface map of objects as small as single atoms.Microscopes are also classified by the type of information they present: size, shape, transparency, crystallinity, color, anisotropy, refractive indices and dispersion, elemental analyses, and fluorescence, as well as infrared, visible, or infrared absorption frequencies, etc. One or more of these microscopes are used in every area of the physical sciences—biology, chemistry, and physics; and also in their subsciences: mineralogy, histology, cytology, pathology, metallography, etc.
Genetic Engineering, Microbes
Authors: Nagarajan Vasantha 
Published: August 2004

AbstractThe techniques involved in isolation and manipulation of genes from several microbes have become routine. Genes are cloned into plasmid or phage‐based vectors and introduced into the microbe of choice. The number of vectors that have been engineered to be versatile is on the increase for several systems. Some vectors are commercially available for gene manipulations from several vendors. In addition, construction of gene libraries and screening are also performed by small biotechnology companies. Most of the reagents needed for gene manipulation such as oligonucleotides, peptides, and antibodies are commercially available. In addition, kits are also accessible for some of the routine tasks such as plasmid isolation, deoxyribonucleic acid (DNA) sequencing, etc. The methods involved in the production of proteins in microbes are those of gene expression. Genetically engineered microbes are used to produce several commercial products. The number of products is likely to increase. They include therapeutics, bulk enzymes, antibiotics, chemicals, and crop protection products.
Molybdenum and Molybdenum Alloys
Authors: Doane D. V. , Timmons G. A. , Hallada C. J. 
Published: August 2004

Abstract
Molybdenum, a key industrial element, is used both in its pure form as a refractory metal and as an alloying element in irons and steels. Most molybdenum production is in North America, although some metal comes from other areas, especially from South America and China. The largest source of molybdenum is copper mines, where the former metal is a by‐product. Molybdenum supply, ore‐processing to commercial products, and the associated environmental considerations are reviewed.
Tools, pipelines, pumps, and various gears and dies, especially those for harsh working environments such as those found in the petroleum industry, are made from molybdenum containing alloys. The molybdenum imparts strength, hardness, and corrosion resistance to steels and cast irons. Molybdenum is a refractory metal used in furnaces, electrodes, light bulbs, and x‐ray tubes. Properties and uses are described.
Graphite, Natural
Authors: Taylor Harold A. 
Published: August 2004

AbstractNatural graphite, the mineral form of graphitic carbon, occurs worldwide. It differs from the carbon of coal and of diamond in its predominantly lamellar hexagonal crystal structure. The ore usually contains associated silicate minerals that vary in kind and amount with the source. The name natural graphite is used in technical terminology and sometimes elsewhere. It may be simply termed graphite or any of several common names such as plumbago, black lead, silver lead, carburet of iron, and reissblei. The macrophysical form depends on geological genesis, whereas the properties depend on both the macrophysical form and associated mineral suite. The commercial value depends on specific characteristics such as form, percentage and kind of mineral suite, and availability. Graphite occurs in widely distributed places as flakes, lumps, and cryptocrystalline masses referred to commercially as amorphous graphite. Parallel layers of condensed planar C6‐rings constitute the graphite crystallite. Weak van der Waals forces pin the carbons in adjoining layers, thus accounting in part for the marked anisotropic properties of the graphite crystal. Solid articles made of natural graphite always require a binder; ie, they are always composites. Graphite's strength increases as the temperature rises. Graphite burns slowly in air above 450°C, the rate increasing with temperature and exposed area. Graphite can be regenerated from the crystal compounds because the graphitic structure has not been too greatly altered. The dark crystal compounds are called intercalation compounds, interstitial compound, or lamellar compounds because they are formed by reactants that fit in between the planar carbon networks. The covalent compounds of graphite differ markedly from the crystal compounds. They are white or lightly colored electrical insulators and have ill‐defined formulas. In the covalent compounds, the carbon network is deformed, and the carbon atoms rearrange tetrahedrally as in diamond. Often they are formed with explosive violence. The many useful properties of graphite give rise to a wide variety of products: unctuous, dry lubricant; marks readily, writing and drafting pencils; combination of lubricity and electrical conductivity, motor and generator brushes; and burns slowly, conducts heat, and retains strength over a large temperature range, refractories such as crucibles, carbon–magnesite brick, and continuously casting ware.
Peptides
Authors: Wise Edmund M. 
Published: August 2004

AbstractPeptide antibiotics are classified according to their overall shape, which can be linear or cyclic, and by the nature of the bonds joining the constituent amino acids and other carboxylic acids, which can be all amide bonds or amide plus ester bonds. Most peptide antibiotics are cyclic peptides that do not contain disulfide linkages. Peptide antibiotics differ in many respects from proteins. The vast majority of peptide antibiotics have molecular weights in the 500–1500 range, whereas the average protein has a mol wt of 40,000. Many peptide antibiotics have unusual fatty acids and amino acids, such asD‐amino acids,N‐methyl amino acids, or imino acids, and they usually lack methionine and histidine. Ring closure in cyclic peptide antibiotics is by amide or ester bonds. Peptide antibiotics are normally resistant to the usual proteases and peptidases. They are usually synthesized on multienzyme complexes much as are fatty acids, and not on ribosomes as are proteins. Most peptide antibiotics are synthesized as groups of closely related structures. Even the small fraction of peptide antibiotics that have therapeutic usefulness are quite toxic. The ratio of the minimum toxic dose to the maximum effective dose is smaller than for most nonpeptide antibiotics. Peptide antibiotics are not often the drugs of first choice for systemic therapy of important human disease. However, the World Health Organization, which chooses drugs especially for Third World use based on efficacy, safety, quality, price, and availability, includes such peptide antibiotics as bleomycin, dactinomycin, and bacitracin, plus several β‐lactams. The complex structure of peptide antibiotics adds considerably to the problems of synthesis, but more recent efforts toward improved peptide antibiotics are encouraging.
Phenolic Resins
Authors: Kopf Peter W. 
Published: August 2004

AbstractPhenolic resins are a family of polymers and oligomers composed of a wide range of structures based on the various reaction products of phenols with formaldehyde. Applications vary from commodity construction materials to high technology applications in electronics and aerospace. Phenolic resins are prepared using acidic or basic catalysts. Weak Lewis acids, such as zinc acetate, are used for specialty resins.Phenolic novolaks are thermoplastic resins prepared from acid catalysts and a molar excess of phenol. They have a molecular weight of 500–5000 and a glass‐transition temperature,Tg, of 45–70°C. Novolak resins are typically cured with 5–15% hexamethylenetetramine as the cross‐linking agent. Resole‐type phenolic resins are produced with a molar ratio of formaldehyde to phenol of 1.2:1 to 3.0:1 and alkaline catalysts such as NaOH, Ca(OH)2, and Ba(OH)2. A typical resin has an initial molecular weight of 150 to perhaps 1500. For systems of unsubstituted phenols, the final cross‐link density is 150–300 atomic mass units per cross‐link.In 1993, worldwide consumption of phenolic resins exceeded\documentclass{article}\usepackage{amssymb}\pagestyle{empty}\begin{document}${3\times 10^{6}{\hskip0.167em}{\hskip0.167em}{\rm{t}}}$\end{document}; slightly less than half of the total volume was produced in the United States, where the largest‐volume application is in plywood adhesives and accounts for ca 49% of U.S. consumption. As a mature industry, U.S. production of phenolic resins has paralleled the growth in the GNP. Applications for phenolic resins include coatings, adhesives, carbonless copy paper, molding compounds, bonded and coated abrasives, friction materials, foundry resins, laminates, air and oil filters, wood bonding, fiber bonding, composites, spherical fillers, and fibers.Factors contributing to the health and safety of phenolic resin are related primarily to the presence of unreacted phenol and formaldehyde. Unreacted phenol in a resin can range from\documentclass{article}\usepackage{amssymb}\pagestyle{empty}\begin{document}${>{\hskip-0.167em}{\hskip-0.167em}10{\%}}$\end{document}for liquid resoles used in impregnation processes to\documentclass{article}\usepackage{amssymb}\pagestyle{empty}\begin{document}${<{\hskip-0.167em}{\hskip-0.167em}1{\%}}$\end{document}for novolaks intended for use as epoxy hardeners. Free formaldehyde can be 2–4% in liquid adhesives.
Photodetectors
Authors: Borrello Sebastian R. , Wadsworth Mark V. 
Published: August 2004

AbstractPhotodetectors, based on photon absorption or thermal emission, are made from semiconductor materials that are very sensitive in the spectral range from ultraviolet to far infrared. Detector figures of merit such as responsivity, noise, noise equivalent power and detectivity, and ideal performance and cooling requirements are given. Modes of operation include charge‐coupled device, photovoltaic diode, photoconductor, and bolometer. Most semiconductor detectors operate as photon detectors where the minimum photon energy detected is defined by a discrete activation energy of the semiconductor. However, micromachined bolometers and superlattice infrared detectors are in development for thermal imaging and chemical spectroscopy. Materials and detector types are discussed.Detector material preparation technologies are presented for intrinsic detectors where the photon absorption coefficient is high, and for the low absorption coefficient detectors such as impurity‐doped Ge or Si. Fabrication technology making possible large photodetector focal planes that detect photons and perform signal processing are integrated structures either in monolithic form or in hybrid form. The monolithic arrays range up to 106detectors. The hybrid focal planes, mostly for infrared detection, contain up to 105. Photodetector arrays have been developed for imaging across the spectrum and are used in CCD cameras, chemical spectroscopy, missile seekers, and night vision equipment.
Fluorine‐Containing Polymers, Poly(Vinyl Fluoride)
Authors: Ebnesajjad S. , Snow L. G. 
Published: August 2004

AbstractHomopolymers and copolymers of vinyl fluoride are based on free‐radical polymerization of vinyl fluoride and comonomers, usually under high pressure. Du Pont first commercialized a poly(vinyl fluoride)‐based film in 1961 under the trade name Tedlar. Poly(vinyl fluoride) homopolymers and copolymers have excellent resistance to sunlight degradation, chemical attack, water absorption, and solvent; they have a high solar energy transmittance rate. These properties have resulted in the utilization of poly(vinyl fluoride) (PVF) film and coating in outdoor and indoor functional and decorative applications. These films are used where exceptional high temperature stability, outdoor longevity, stain resistance, adherence, and release properties are required.
Coating Processes, Powder Technology
Authors: Richart Douglas S. 
Published: August 2004

AbstractThe coating processes used to apply coating powders all employ a fusion coating method. The individual power particles are melted and fused together to form a continuous coating useful in thin film, decorative, or thicker film functional applications. Application methods include the use of fluidized beds, electrostatic sprays employing both corona discharge and triboelectric guns, electrostatic fluidized beds, and hot flocking. Both thermoplastic coating powders based on nylon, plasticized PVC, or several fluoropolymers, as well as thermosetting coating powders are used. Thermosetting coating powders based on epoxy resins, epoxy‐polyester combinations, polyester‐TGIC cured, polyesters cured with blocked isocyanates, and acrylic resins are described. Properties of powder coatings are described as are the test methods and regulations regarding the coating powder. Methods of manufacturing coating powders include melt‐mixing and dry‐blending processes. Usage of powder coatings for both industrial and architectural applications is increasing worldwide.
Bleaching Agents, Pulp and Paper
Authors: McDonough Thomas 
Published: August 2004

Abstract

Worldwide, more than

\documentclass{article}\usepackage{amssymb}\pagestyle{empty}\begin{document}${50\times 10^{6}{\hskip0.167em}{\hskip0.167em}{\rm{t}}}$\end{document}

of pulp is bleached annually, making the pulp and paper industry one of the largest consumers of bleaching chemicals. The principal objective in bleaching any type of pulp is usually to increase the whiteness of the pulp, as measured by its brightness, which is defined as reflectance measured at a wavelength of 457 nm. Virtually all of the color of any pulp resides in its lignin component. Because concurrent cellulose damage would seriously weaken the fibers, pulping is therefore terminated when 5–8% of the original lignin remains. Bleaching effluent is typically contaminated with chloride ion and chlorine compounds, making it difficult or impossible to recycle it to the recovery system because of potential for corrosion. It is therefore necessary to treat and discharge the bleaching effluent. Associated environmental concerns are presently causing rapid changes in bleaching technology. With the exception of caustic, all important chemical pulp bleaching agents are oxidants, eg, chlorine, Cl
2
; chlorine dioxide, ClO
2
; calcium hypochlorite, Ca(OCl)
2
; hydrogen peroxide, H
2
O
2
; oxygen, O
2
; and ozone, O
3
. Research in progress points to the possible commercialization of several other chemical pulp bleaching technologies: chemical pretreatments to improve the selectivity of oxygen bleaching, enzymatic pretreatments to facilitate subsequent delignification, and recycling of bleach plant effluents. Much new high yield pulping technology has been developed, including production of thermomechanical pulp (TMP) and chemithermomechanical pulp (CTMP). Because little material is lost in these processes, and the pulps have a very high lignin content, it is not feasible to bleach them by removing all of the lignin, as in chemical pulp bleaching. Instead, the lignin must be decolorized, a process sometimes referred to as brightening. Only two brightening agents, hydrogen peroxide and sodium hydrosulfite (sodium dithionite), are of commercial importance. Because pulp bleaching agents are, for the most part, reactive oxidizing agents, appropriate precautions must be taken in their handling and use. Hazards associated with pulp bleaching agents include their potential for damage resulting from contact with skin or eyes, their ability, as oxidizers, to cause fires or explosions. Additional information on health and safety aspects should be sought by consulting material safety data sheets. Most suppliers of bleaching chemicals provide on‐site training sessions by experts on the safe use and handling of their products, upon request.
Release Agents
Authors: Owen Michael J. 
Published: August 2004

Abstract
Owen, Michael J. (Dow Corning Corp.). Release agents are used to minimize adhesion between surfaces in many industrial processing and handling operations such as extrusion, molding, transferring, and packaging. They function either by lessening intermolecular interactions between surfaces or by preventing close contact. Consequently, they are either low surface‐tension materials such as fatty acid derivatives, natural and synthetic waxes, and polymers such as polytetrafluoroethylene and polydimethylsiloxane, or particulate solids such as silica or mica. The principal classes of materials used are waxes, fatty acid metal soaps, other long‐chain alkyl derivatives, polymers, and fluorinated compounds. These are formulated into products of various forms, including solvent solutions, emulsions, and films. They are widely used in the metal, glass, rubber, plastics, furniture, and food industries. Some key material transfer processes critically dependent on release agent technology include hot stamping foils, pressure‐sensitive adhesives, photocopying, transfer coatings, and transfer printing of textiles. Growth is modest, but new products are evolving. The trend is from solvent to waterbourne systems, and from single‐application products to semipermanent types. Vol. 21, pp. 207–218, 31 refs. to June 1994.
Toluenes, Ring‐Chlorinated
Authors: Lin Henry C. , Krishnamurti Ramesh 
Published: August 2004

AbstractThe preparation, physical and chemical properties, and applications on mono‐, di‐, tri‐, tetra‐, and pentachlorotoluenes are reviewed. Reactions of chlorotoluenes are classified into those involving the aromatic ring, the methyl group, and the halogen. The reactions involving the methyl group are widely used to synthesize a variety of functionalized chloroaromatic compounds. Some of the recent applications of these compounds are based on replacement of the halogen by other functional groups catalyzed by transition‐metal compounds. Monochlorotoluenes are obtained generally by reaction of toluene with chlorine under a variety of homogeneous and heterogeneous conditions. The higher chlorotoluenes are obtained usually by chlorination of the lower chlorinated analogues. Many detailed studies have been conducted to evaluate the toxicological properties of chlorotoluenes. Ring‐chlorinated toluenes find principal applications in the pesticide, pharmaceutical, peroxide, dye, and other industries.p‐Chlorotoluene is an especially valuable starting material to prepare numerous, industrially useful intermediates.
Silver and Silver Alloys
Authors: Etris Samuel F. 
Published: August 2004

Abstract
The workability, beauty, and bacteriocidal effects of silver have made it a most desirable metal since ancient times. The combination of desirable properties and the total resistance of silver to the formation of oxides has established its position as a critical metal for a myriad of advanced technology applications. Silver also imparts the properties to the many metals with which it forms commercially important alloys. Among its many important salts, the halides stand as unique photosensitive salts, providing the basis for high quality photography as well as for photochromic glass.
More obscure properties of silver such as its high thermal reflectivity are also being fully exploited. For example, silver is used to provide energy‐saving domestic window glass. The unique interaction of silver and oxygen is being used to advantage in the superconductor industry. The superior fatigue resistance and lubricity of silver make it an essential component of high performance jet engines.
Antibacterial Agents, Sulfonamides
Authors: Foye William O. 
Published: August 2004

AbstractSulfonamides derived from sulfanilamide (p‐aminobenzenesulfonamide) are commonly referred to as sulfa drugs. The sulfa drugs are still important as antimicrobials, although they have been replaced in many systemic infections by the natural and semisynthetic antibiotics. They are of great value in Third‐World countries where problems of storage and lack of medical personnel make appropriate use of antibiotics difficult. They are especially useful in urinary tract infections, particularly the combination of sulfamethoxazole with trimethoprim, and the combination of sulfamethoxazole with trimethoprim is of value in treatment of a number of specific microbial infections. The introduction of this combination (cotrimoxazole) in the late 1960s (1973 in the United States) resulted in increased use of sulfonamides. The sulfas also remain clinically useful in the treatment of chancroid, lymphogranuloma venereum, trachoma, inclusion conjunctivitis, and the fungus‐related nocardiosis. The sulfone, dapsone, remains an accepted treatment for all forms of leprosy. Currently used sulfas vary widely in their absorption, distribution, and excretion patterns. Some of those in clinical practice, past or present, are sulfanilamide, sulfacetamide, sulfadiazine, sulfadimethoxine, sulfaguanidine, sulfisomidine, sulfisoxazole, sulfamethazine, sulfamethizole, sulfamethoxazole, sulfamethoxypyridazine, sulfamoxole, sulfaphenazole, sulfapyridine, sulfapyrazine, and sulfathiazole. The action of the sulfa drugs and related sulfones is bacteriostatic rather than bactericidal. Numerous studies have been made to find a correlation between the physicochemical properties of the sulfonamides and their bacteriostatic activity. Degree of ionization, lipid–water solubility, electron distribution values, and protein binding have all been observed. One of the principal disadvantages of sulfonamide therapy is the emergence of drug‐resistant strains of bacteria. The most common method for the preparation of sulfonamides is by the action ofN‐acetylsulfanilyl chloride with the appropriate amine. A small percentage of patients treated with sulfa drugs have shown toxic effects, such as drug fever, rashes, mild peripheral neuritis, and mental disturbance. In 1966 the FDA required that two long‐acting sulfas, sulfamethoxypyridazine and sulfadimethoxine carry a label warning of the possibility of death due to Stevens‐Johnson syndrome, an extremely severe dermatologic reaction. Blood dyscrasias are quite uncommon, but if they occur may be serious enough to cause discontinuance of the therapy. Administration of sulfas can cause hypersensitivity reactions, but in general, use of sulfonamide therapy is considered relatively safe.
Carboxylic Acids, Survey
Authors: Bagby M. O. 
Published: August 2004

AbstractCarboxylic acids from formic (C‐1) to the 22‐carbon fatty acids and selected examples of higher carbon number (C‐30) are reviewed. Available physical properties are tabulated for normal saturated and selected unsaturated and substituted aliphatic acids. The physical properties as well as chemical properties are discussed briefly.