bluuebunny/crossref_metadata_2025_split huggingface dataset:
Automated Instrumentation, Hematology
Authors: Zelmanovic David , Garcia Roque A. , Turrell John 
Published: July 2004

AbstractHematology analyzers provide information about blood cells and their constituents. The three basic blood cell types are erythrocytes or red blood cells, leukocytes or white blood cells, and thrombocytes or platelets. Hemoglobin is the principal nonaqueous component of red blood cells. Its physiological importance gives it the status of a primary hematological constituent. The aperture impedance principle of blood cell counting and sizing, also called the Coulter principle, exploits the high electrical resistivity of blood cell membranes. In the aperture impedance method, in its simplest form, a d‐c current flows between the electrodes. The resistive cells reduce the current as the cells pass through the aperture, and the current drop is sensed. Aperture impedance counters are flow cytometers, as are all current automated cell counters. Flow cytometers measure cells as the cells flow hydraulically, one at a time, through sensing zones. Aperture impedance counters provide cell volume information as well as cell counts. The light‐scattering principle of cell counting is based on the observation that microscopic particles, such as blood cells, scatter into small (0–15°) angles, most of the visible light incident upon them. This principle is used to count red blood cells, white blood cells, and platelets. The basic single‐angle interval light‐scattering method cannot accurately measure individual red blood cell or platelet volumes, but it can provide mean red cell volume (MCV) and mean platelet volume (MPV). A sphered cell's volume and the hemoglobin concentration can both be accurately determined from Mie Scattering Theory calculations by making simultaneous measurements of light‐scatter intensity over two suitably chosen angle interval. Two suitable angle intervals for red cells are 2–3°, known as low angle scatter (SL), and 5–15°, high angle scatter (SH). Cytochemical techniques can be combined with light‐scattering and absorption measurements to provide five‐part Diffs. Cytochemistry concerns the chemical reactions of cell components. Various method combinations can be used to produce five‐part Diffs including d‐c/r‐f aperture impedance plus light scattering; two‐angle interval light‐scattering plus depolarized light scattering; light scattering plus cytochemistry; and d‐c/r‐f aperture impedance plus cytochemistry. Flow cytometric methods produce five‐part Diffs that are generally more precise and accurate than manual Diffs. However, manual methods can provide more information. Most automated hemoglobinometry methods are derivatives of the manual ICSH reference method, in which the blood sample is diluted in a reagent to lyse the RBC membrane, releasing hemoglobin into solution, ferricyanide present in the diluent diffuses into the hemoglobin molecule yielding methemoglobin, and cyanide diffuses into methemoglobin's interior and reacts with heme to yield cyanmethemoglobin (HiCN), which is measured spectrophotometrically.
Hemicellulose
Authors: Thompson Norman S. 
Published: July 2004

AbstractHemicellulose, a poorly utilized component of arborescent plants, is a complex mixture of polysaccharides, each exhibiting polydispersity, polymolecularity, and polydiversity to varying extents. Hemicellulose is defined in this article as the noncellulosic polysaccharides that make up the cell wall structure of vegetable material, but other definitions based on solvent behavior also occur in the literature. The most common polysaccharides included in all definitions are xylans, arabinogalactans, and pectic materials of varying compositions found in gymnosperms and angiosperms, glucomannans found in gymnosperms and dicotyledons but seldom, if at all in monocotyledons, and β‐D‐glucans found only in monocotyledons. Xylans and glucomannans are the primary hemicellulose components of fibers and tracheids of arborescent plants, but other unique hemicellulose components may occur in significant quantities in other parts of the plant. The intimate association of hemicellulose with lignin and cellulose makes it difficult to isolate without unwanted degradation. Some mixtures of hemicellulose components cannot be separated in a quantitative manner. The utilization of hemicellulose components is complicated by their complexity and because of the transformations that they have undergone in many manufactured products. They affect the products in which they are present, being harmful in dissolving pulps and a mixed blessing in paper products, and are generally a beneficial components of foods.
High Pressure Technology
Authors: Bett K. E. 
Published: July 2004

AbstractThe growth in the use of high pressure by the chemical industry during the twentieth century, leading to the discovery of polyethylene by ICI in the early 1930s, is described briefly. At that time, the pressures required for the large‐scale production of low density polyethylene (LDPE) were well beyond the normal design practices for continuously operating plants and the development of the process in both the United States and Europe posed formidable problems. This led to a number of different modifications to the high pressure procedure used by ICI.The basic principles governing the design of thick‐walled cylinders to withstand static high internal pressure are reviewed. It is shown how these principles together with the results of much work carried out since the 1940s, particularly that directed toward increasing the fatigue strength of cylinders subjected to pulsating internal pressure, were used to develop both stirred and tubular reactors, reciprocating compressors, initiator pumps, etc, for use in the production of LDPE at pressures up to about 345 MPa.Most of the article is devoted to the design of continuous chemical plants; some attention is given to the problems of designing equipment for isostatic compaction which is operated as a batch process.
High Temperature Alloys
Authors: Stoloff Norman S. 
Published: July 2004

AbstractHigh temperature alloys are combinations of metals used specifically for their heat resisting properties. Applications in the aircraft, automotive, power generation, and space‐related industries include use in steam and gas turbine engines, as cutting tools, and as various spacecraft parts.The alloys most often used at high temperatures include steels, superalloys, refractory metal alloys, and new materials such as aligned eutectics and intermetallic compounds. These alloys, their properties and surface stability, mechanical behavior, and the strengthening mechanisms employed are discussed.Various plain carbon and low alloy steels are employed as are modified stainless steels. Superalloys may have nickel, cobalt, or iron–nickel bases. The nickel‐base superalloys are most often used for high temperature structural applications in air. The Group 6 (VIB) metals and their alloys and various new materials are often employed as cutting tools and in spacecraft.
High Purity Gases
Authors: Whitlock Walter H. , Ezell Edward F. , Hwang Shuen‐Cheng 
Published: July 2004

Abstract
High purity industrial gases are routinely delivered in large quantities having purities exceeding 99.999% (>5 nines pure). Other commodity materials, whether in liquid or solid form, much less typically have purity exceeding 99.9%. There are many applications for gases where purity even higher than 99.999% is required. To service these applications, the technology for manufacturing and delivering high purity gases has developed into a multibillion dollar business worldwide. Japan and the United States have the majority of the market.
There is no universally accepted definition of what purity levels correspond to high purity. A good working definition of high purity is gases having certain individual impurities held to levels <0.1 ppm.

The technology for manufacturing and delivering high purity gases has largely developed to support the manufacture of advanced semiconductor materials needed as part of the overall process of manufacturing integrated circuits. Purity requirements in some of these high performance materials have reached the point where impurity concentrations in the starting gases of 1 part in 10
12
have been related to reduced yields and poor performance in the resulting integrated circuits. Depending on a volume, high purity gases can be delivered using either bulk systems, where a plant‐wide distribution system is integrated with central gas storage facilities, or cylinders, where a short local distribution system is supplied from a single high pressure cylinder.

Gases used in the manufacture of semiconductor materials fall into three principal areas: the inert gases, used to shield the manufacturing processes and prevent impurities from entering; the source gases, used to supply the molecules and atoms that stay behind and contribute to the final product, and the reactive gases, used to modify the electronic materials without actually contributing atoms or molecules.
Histamine and Histamine Antagonists
Authors: Janssens Monique M.‐L. , Timmerman Hendrik , Leurs Robert 
Published: July 2004

AbstractHistamine, endogenously formed by decarboxylation of histidine, is stored preformed and released during allergic, reactions. Histamine is also responsible for gastric acid secretion, functions as a neurotransmitter in the brain, and may have a physiological role in the cardiovascular system. The actions of histamine are mediated through H1, and H3receptors. The H1receptor mediates most of histamine's effects in allergic diseases and H1receptor antagonists are used in the treatment of such diseases as allergic rhinitis and urticaria. Classical H1antagonists, primarily all substituted ethylamines, cause sedation, whereas second‐generation H1antagonists do not. Both types of H1antagonists are described. The most important effect mediated through H2receptors is gastric acid secretion. H2agonists and antagonists are described. The antagonists are available for the treatment of peptic ulcer disease and esophageal reflux. The H3receptor is present in the brain and in peripheral tissues modulating the release of a variety of neurotransmitters. H3agonists and antagonists are described. No clear therapeutic indications have been reported for H3ligands.
Hollow‐Fiber Membranes
Authors: Moch Irving 
Published: July 2004

AbstractHollow‐fiber membranes were invented in the 1960s. In the ensuing decades much research and development effort has transpired with the result that these fibers have become exceedingly important to industry, academia, and government in such fields as desalination of water, wastewater reclamation, medicine, agriculture, gas separation, and pervaporation. Commercial opportunities annually exceed several hundred million dollars. The hollow‐fiber membranes are usually the base technology within a significantly larger system.This article briefly discusses the history and theory of hollow‐fiber membrane technology. Methods of manufacture are reviewed together with processing techniques employed to enhance various aspects of performance. Hollow‐fiber membranes are composed of many different materials of construction. The generic compositions are cited and specific end use applications noted. Lastly, the work to date has identified many areas where future prospects for hollow‐fiber membranes are the brightest. A number of these future growth areas are discussed together with which industrial corporations are in the forefront of the new developments.
Holography
Authors: Honh John H. 
Published: July 2004

Abstract
Holograms are capable of storing and displaying the optical waves scattered by an object wholly in a way that is completely unique from photographs which are, at best, accurate but flat projections. A hologram is essentially an interferometric, record of a wavefront so that the whole character of the wave, its amplitude, and phase, is captured. This article describes the fundamentals of optical holography, beginning with a discussion of the holographic principle and concluding with descriptions of important applications in the areas of displays, interferometry, data storage, and information processing. The large variety of hologram formats, materials, and techniques available to the holographer is explored in some detail with mathematical expressions that model the optical behavior of specific types of holograms given whenever appropriate.
Hydrogen Energy
Authors: Billings Roger E. 
Published: July 2004

AbstractBillings, Roger E. (International Academy of Science). Hydrogen energy is expected to play an important role in the energy of the twenty‐first century in part because of increased concerns about environmental pollution, depleting fossil fuel resources, and advances in utilization technologies.Costs of hydrogen production and hydrogen storage appear to be the limiting steps. Hydrogen can be utilized in a variety of energy applications including as a fuel for the internal combustion engine. Hydrogen can be safely stored at ambient pressures as powdered metal hydride. Testing of hydrogen‐fueled prototype vehicles has demonstrated higher utilization efficiencies for hydrogen than for conventional fossil fuels. Hydrogen has also been utilized as a fuel for household appliances originally manufactured to operate on natural gas.Hydrogen can be efficiently converted into electricity by means of a hydrogen fuel cell. Such a device can generate electric power for stationary applications or for electric vehicles. Hydrogen fuel cells are two to three times more efficient than conventional internal combustion engines.
Hydroxy Dicarboxylic Acids
Authors: Blair Gary T. , DeFraties Jeffrey J. 
Published: July 2004

AbstractMalic acid and tartaric acid are two hydroxy dicarboxylic acids of commercial significance. Thiomalic acid and derivatives of malic and tartaric acid are discussed briefly. For malic and tartaric acids, physical and chemical properties, manufacturing process, commercial significance, health and safety properties, and primary applications, including food, pharmaceutical, and industrial, are reviewed. The primary chemical reactions are summarized; chelation and corrosion are discussed. The primary chemical reactions are summarized; chelation and corrosion are discussed. The commercial production procedures for malic acid and tartaric acid are summarized. Compendial specifications (Food Chemicals Codex, National Formulary) for malic acid and tartaric acid are listed.
Hydrogen Peroxide
Authors: Eul W. , Moeller A. , Steiner N. 
Published: July 2004

AbstractHydrogen peroxide is a strong oxidizing agent commercially available in aqueous solution over a wide concentration range. Its many uses involve its varied chemistry and are based on oxidations, reductions, substitutions, molecular additions, and decompositions. Product from hydrogen peroxide decomposition are the environmentally benign oxygen and water. Manufacture and use, especially in industrial bleaching applications, are on the rise, fueled by environmental concerns and econological pressure to replace chlorine‐based bleaching with the cleaner peroxide chemistry.Manufactured primarily in large, strategically located anthrahydroquinone autoxidation processes, the primary use for hydrogen peroxide is in bleaching wood pulp. Hydrogen peroxide is also produced electrolytically. The various manufacturing processes are discussed. Safe use and handling require adherence to approved procedures and use of proper protective equipment.
Hydrogen Chloride
Authors: Hisham Mohamed W. M. , Bommaraju Tilak V. 
Published: July 2004

AbstractHisham, Mohamed W. M. and Bommaraju, Tilak V., (Occidental Chemical Corp.). Hydrogen chloride, a gas at ambient temperature and pressure, is very soluble in water. Hydrogen chloride can be produced by direct reaction of the elements, by reaction of metal chlorides and acids, and as a by‐product from many chemical manufacturing processes such as those for chlorinated hydrocarbons. Over 90% of the hydrogen chloride produced in the United States is as a by‐product from various chemical processes. HCl is produced as a by‐product in the manufacture of chlorofluorohydrocarbons, aliphatic and aromatic hydrocarbons, production of high surface area silica, and the manufacture of phosphoric acid and esters of phosphoric acid. Crude by‐product HCl is generally contaminated with impurities of the process. A wide variety of techniques are employed to treat the HCl streams to obtain either anhydrous HCl or hydrochloric acid. Technologies have been developed for burning or pyrolyzing waste organics and recovering the chlorine values as hydrogen chloride.Hydrogen chloride and its aqueous solution, muriatic acid, find application in many industries. In general, anhydrous HCl is consumed for its chlorine value, whereas aqueous hydrochloric acid is often utilized as a nonoxidizing acid, in metal‐cleaning operations, chemical manufacturing, petroleum well activation, and the production of food and synthetic rubber. Most of the HCl produced is consumed captively either in integrated operations, eg, chlorinated methane plants, or in separate HCl‐consuming operations at the same location.
Hydrocarbon Oxidation
Authors: Hobbs Charles C. 
Published: July 2004

AbstractHydrocarbon oxidation has long been a significant source of organic chemicals. Both vapor‐ and liquid‐phase reactions are of interest; they are believed to involve free‐radical chain mechanisms. Modern understanding of these reactions has developed over the last half of the twentieth century. Although sharp disputes are frequent, significant agreement on underlying principles is apparent.Vapor‐phase oxidations can be conveniently divided into low, middle, and high temperature ranges. Fundamental changes in mechanisms occur over these regions. The direct oxidation of methane to methanol, formaldehyde, and/or C2products has received intense study, but no viable processes have yet been developed. Most other studies in this area are directed toward fuel utilization and pollution abatement.Liquid‐phase oxidations of aliphatics have declined in importance as sources of bulk chemicals. However, the oxidation of butane to acetic acid, and of isobutane tot‐butylhydroperoxide (to produce propylene oxide), and of cyclohexane to cyclohexanol and cycohexanone (to produce adipic acid and nylon), remain important industrial processes. Oxidations of alkylaromatics continue to be important industrially. The oxidation ofp‐xylene to terephthalic acid and cumene to phenol are dominant routes to these products. The potential for producing fine chemicals by such oxidations is developing rapidly.
Aluminum Oxide (Alumina), Hydrated
Authors: Misra Chanakya 
Published: July 2004

Abstract

The term alumina hydrates or hydrated aluminas is used in industry and commerce to designate aluminum hydroxides. These compounds are true hydroxides and do not contain water of hydration. The most well‐defined crystalline forms are the trihydroxides, Al(OH)
3
: gibbsite, bayerite, and nordstrandite. In addition, two aluminum oxide–hydroxides, AlO(OH), boehmite and diaspore, have been clearly defined. The terms gelatinous alumina or alumina gel cover a range of products in which colloidal hydrated alumina is the predominant solid phase. Structural order varies from x‐ray indifferent (amorphous) to some degree of crystallinity. Apart from the crystalline forms, aluminum hydroxide often forms a gel. Gel products have considerable technical use. Aluminum hydroxides are technically the most widely used members of the alumina chemicals family. The most important source of aluminum hydroxides is the bauxite refining plant (Bayer process) for alumina production. Several commercial grades of aluminum hydroxide are produced. Hydroxide grades can be surface‐treated to modify dispersion behavior and rheological properties. Aluminum hydroxides are minimally absorbed by the body. Death upon ingestion occurs from intestinal blockage rather than systemic aluminum toxicity. In recognition of the possible adverse effects of long‐term exposure to alumina dusts, threshold limit values have been established by the ACGIH. Aluminum hydroxide and aluminum hydroxide oxide are reported in EPA TSCA inventory.
Hydrides
Authors: Eggeman Tim 
Published: July 2004

AbstractSullivan, Edward A. (Morton International). Hydrides may be divided into two groups: simple and complex. The simple or binary hydrides may be ionic, covalent, or interstitial as are most of the transition metal hydrides. The important properties, methods of manufacture, safe handling, and important uses of the commercial binary hydrides and certain hydrogen storage alloys are reviewed. Alkali metal, alkaline‐earth, and Group 4, 5, 13, and 14 hydrides find use in a variety of industries among which are the electronics, pulp and paper, dyeing, and clay industries.The most important complex hydrides are the borohydrides and alumino‐hydrides. The important alkali metal salts of these hydrides are described. Complex hydrides are used principally in the synthesis of organic compounds effecting specific and nonspecific reductions. Alkoxyborohydrides, cyanoborohydride, acyloxyborohydrides, and alkoxy‐aluminohydrides, are also discussed.
Imines, Cyclic
Authors: Scherr G. , Steuerle U. , Fikentscher R. 
Published: July 2004

AbstractThis article describes aziridines with particular emphasis on the parent compound ethyleneimine. The physical and chemical properties of ethyleneimine, such as aminoethylation, synthesis of heterocycles, and polymerization, are discussed. Current industrial production methods, economic aspects, analytical and test methods, storage and toxicology, and safe handling procedures for ethyleneimine are described. The wide‐ranging applications of ethyleneimine derivatives, including the paper industry, extraction and complexing, additives, fixing, textile finishing, flocculation, electroplating, medicine, membranes and osmosis, and tertiary crude oil extraction are reviewed.
Immunoassay
Authors: Taylor Richard F. 
Published: July 2004

AbstractImmunoassay, a diagnostic and measurement method which utilizes antibodies to detect and quantify specific analytes (antigens), is characterized by high analyte specificity, high sensitivity (routinely detecting ng to pg analyte levels), and rapid data output. It is amenable to a variety of formats, from single immunoassays carried out manually, to fully automated instruments capable of performing multiple assays on the same or different analytes. Immunoassay quantification methods are based on immunoprecipitation, such as agglutination assays, or on specific indicator reagents linked to antibody or antigen reagents used in the immunoassay. These include radioisotopes for radioimmunoassay, enzymes for enzyme‐linked immunoassay, fluorophores for fluorescence immunoassay, and chemiluminescent labels for chemiluminescent immunoassay. Immunoassay technology is continuing to evolve and applications are reaching beyond traditional clinical settings to industry and the environment. Immunoassays are also serving as the basis for newer measurement technologies including hybrid immunoassay–nucleic acid probe assays and immunobiosensors.
Incinerators
Authors: Diemer R. Bertrum , Ellis Thomas D. , Silcox Geoffrey D. , Lighty JoAnn S. , Pershing David W. 
Published: July 2004

AbstractMany industrial manufacturers, municipalities, and most medical facilities use thermal destruction by incineration to dispose of wastes. Increased research has led to greater understanding of thermal destruction processes and the systems required to meet environmental regulations such as those of the U.S. Environmental Protection Agency governing the design and operation of incinerators. Incineration systems and theoretical phenomena for the destruction of liquid, solid, and gaseous wastes are described. Methods for establishing the appropriate technology are discussed. Evaluation of combustion mechanisms and the products of combustion, along with equipment needed to remove atmospheric pollutants, are described.