bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sedimentation
Authors: Svarovsky Ladislav 
Published: July 2004

AbstractSedimentation as it applies to gravitational settling of solid particles is discussed. Other aspects included are the pretreatment of slurries to improve settling rates and the enhancement of settling by slow cyclonic action. The fundamental principles of sedimentation are reviewed for free, hindered, and zone settling of solids. The effects of coagulation and flocculation are also presented in terms of how these affect the gravity sedimentation process. A discussion of the batch settling tests on real suspension and the way industrial settlers are sized, as well as a review of clarifiers and thickeners, is included.
Selenium and Selenium Compounds
Authors: Hoffmann J. E. , King M. G. 
Published: July 2004

AbstractSelenium, the 30th most abundant element, lies between sulfur and tellurium in Group 16 (IVA) of the Periodic Table. There are no ores mined for selenium value. Rather, selenium is recovered throughout the world as a by‐product in the refining of sulfide‐bearing copper minerals. Those processes are discussed.The chemical and physical properties of selenium are often similar to those of sulfur but are sufficiently different to account for specialized industrial applications. Both inorganic and organic compounds are known. Principal markets for selenium include those as decolorizing agents in glass, photoreceptors for xerography, stable high temperature pigments, free machining additives for steel and brass, and as a nutritional additive to animal and human diets. Selenium deficiency occurs in some parts of the world and diseases relating to this deficiency have been discovered.
Light Generation Semiconductor Lasers
Authors: Temkin Henryk 
Published: July 2004

AbstractSemiconductor lasers are versatile and easy to use devices having a wide range of applications that include consumer products such as compact disc players and high speed telecommunications networks. The basic concepts needed to understand their operation, from ap–njunction to conditions needed to reach threshold, to the design of double heterostructures, are presented as is a description of lattice matched and strained quantum wells. Materials systems composed principally of Group 13–15 (III–V) elements used for the fabrication of near‐infrared and visible lasers are discussed. Band gaps and lattice constants are given for these systems and for Group 2–16 and 12–16 (II–III) systems. The design and performance characteristics of specific laser types ranging from high power laser arrays to narrow linewidth distributed feedback lasers are presented.
Sensors
Authors: Hughes R. C. , Ricco A. J. , Butler M. A. , Martin S. J. 
Published: July 2004

AbstractHughes, R. C.; Ricco, A. J.; Butler, M. A.; and Martin, S. J. (Sandia National Laboratories). Sensor technology is being revolutionized by advances in microelectronics and optoelectronics. Thus, modern sensor systems almost always include data acquisition capabilities. Rapid advances in sensor technology have increased the difficulty of the task of finding the best sensor system for a given application. A generic scheme for decision‐making is presented. Sensors, generally far from perfect, are often expected to function in hostile environments and to be immune to interference. A variety of sensor technologies are discussed. The most common is silicon processing technology, in which the sensing elements are micromachined into the same chip as the integrated circuit. Also possible are hybrid chips joined after the integrated circuit is formed. Photodetectors, smart sensors, and chemical sensors may be based on silicon processing technology. Other technologies involve the use of acoustic waves, optical fibers, electrochemical systems, and semiconducting metal oxides.
Shape‐Memory Alloys
Authors: Vaidyanathan R. 
Published: July 2004

Abstract
Shape‐memory alloys (SMAs) when deformed can produce strains as high as 8%. Heating results in a phase transformation and associated recovery of all the accumulated strain, a phenomenon known as shape‐memory. This strain recovery can occur against large forces, resulting in their use as actuators. Associated with this behavior is the superelastic or pseudoelastic effect (SE) wherein large and completely recoverable strains are generated mechanically rather than thermally. Whereas the alloys are primarily nonferrous, some ferrous alloys also exhibit shape memory. Applications of SMAs include those as tubes and valves in piping systems for power plants, ships, and the petroleum industry; use as explosive bolts in the aerospace and construction industry; as packaging devices for electronic materials; and as dental materials, prosthetics, and biomedical devices. Shape‐memory alloys may be found in sensors in automobiles, in consumer products, and generally in smart materials and adaptive structures.
Silicon Compounds, Silicon Esters
Authors: Arkles Barry 
Published: July 2004

Abstract
Silicon esters are silicon compounds that contain an oxygen bridge from silicon to an organic group, ie, Si–OR. The most prevalent is tetraethoxysilane. The applications for tetraalkoxysilanes are classified roughly by whether the Si–OR bond is expected to remain intact or be hydrolyzed in the final application. Applications in which the Si–OR bond is hydrolyzed include as binders for foundry‐mold sands used in investment and thin‐shell castings; as binders for refractories; and as resins, coatings, sol–gel glasses, cross‐linking agents, and adhesion promoters. Applications in which the Si–OR bond remains intact include as heat‐transfer and hydraulic fluids. The hydrolysis reaction, which yields polymers of silicic acid that can be dehydrated to silicon dioxide, is of considerable commercial importance. The chemistry and properties of alkoxysilanes and related acyloxysilanes and aspects of commercial production and utilization are reviewed. Sol–gel technology is discussed.
Silicon Carbide
Authors: Divakar R. , Chia K. Y. , Kunz S. M. , Lau S. K. 
Published: July 2004

AbstractSilicon carbide, SiC, is a crystalline material having a color that varies from nearly clear through pale yellow or green to black, depending on the amount of impurities. It occurs naturally only as the mineral moissanite in the meteorite iron of Canon Diablo, Arizona. The commercial product, which is made in an electric furnace, is usually obtained as an aggregate of iridescent crystals. The iridescence is caused by a thin layer of silica produced by superficial oxidation of the carbide. The loose black or green grain of commerce is prepared from the manufactured product by crushing and grading for size. Traditionally, the metallurgical, abrasive, and refractory industries are the largest users of silicon carbide. SiC is also used for heating elements in electric furnaces, in electronic devices, and in applications where its resistance to nuclear radiation damage is advantageous. The development of advanced pressureless sintering and complex shape‐forming technologies has led to silicon carbide becoming one of the most important structural ceramics. Silicon carbide has found wide acceptance in wear‐, erosion‐, and corrosion‐resistant applications; it has demonstrated excellent performance as a heat‐exchanger material; it is also being evaluated for prototype high temperature gas turbine engine component applications. The measurements made on commercial, polycrystalline products should not be interpreted as being representative of single‐crystal silicon carbide. The pressureless‐sintered silicon carbides, being essentially single‐phase, fine‐grained, and polycrystalline, have properties distinct from both single crystals and direct‐bonded silicon carbide refractories. Silicon carbide may crystallize in the cubic, hexagonal, or rhombohedral structure. Silicon carbide is a leading candidate material for rotating and static components in many gas turbine engine applications. As is the case for other ceramics, silicon carbide is brittle in nature. The strength of a silicon carbide component is determined by preexisting flaws introduced into the material during processing. Sintered silicon carbide retains its strength at elevated temperatures. Silicon carbide is a semiconductor: it has a conductivity between that of metals and insulators or dielectrics. Silicon carbide is comparatively stable. The only violent reaction occurs when SiC is heated with a mixture of potassium dichromate and lead chromate. There are several routes to preparing SiC powders. Methods that have been examined include growth by sublimation from the vapor phase, carbothermic reduction, and crystallization from a melt. The high modulus, high intrinsic strength, and temperature stability make SiC, in the form of whiskers, platelets, and fibers, a promising candidate reinforcement material for metal, polymer, and ceramic matrix composites. Silicon carbide has been described as a mild inhalation irritant. The threshold limit value for silicon carbide in the atmosphere is 5 mg/m3.
Semiconductors, Silicon‐Based Semiconductors
Authors: Rose Kenneth 
Published: July 2004

Abstract

Their unique properties have allowed silicon‐based semiconductor devices, especially metal/oxide/semiconductor field‐effective transistors (MOSFETs), to dominate the electronics industry. Exponentially increasing numbers of transistors on single chips of silicon have led to exponential improvements in chip performance. The properties of silicon as an electronic material, the dependence of carrier statistics on doping, and carrier transport are reviewed because they determine device behavior. The characteristics of transistors, both bipolar and MOSFET, depend on the properties of
p–n
junctions. An abrupt
p–n
junction places acceptor‐doped,
p
‐type silicon next to donor‐doped
n
‐type silicon. The performance of
n–p–n
bipolar transistors depends on minority electrons injected into the
p
‐type base by the forward‐biased base‐emitter
p–n
junction reaching the reverse‐biased base‐collector
p–n
junction.
n
‐Channel MOSFETs depend on electrons traveling between

\documentclass{article}\pagestyle{empty}\begin{document}${n^{+}}$\end{document}

source and drain junctions through an
n
‐type surface channel. This surface channel is induced by a voltage applied across the MOS capacitor formed by a polysilicon metal gate over an oxidized silicon surface. The unique low concentration of surface states, which can be achieved at a thermally oxidized Si–SiO
2
boundary, is the basis of MOSFET technology. The ability to shrink the dimensions of these devices without radically altering their behavior (scaling) has allowed the microelectronics industry to place exponentially increasing numbers of MOSFETs on a single chip. Generally speaking, the growth of the microelectronics industry has been the result of device scaling rather than fundamental changes in device physics. Variations of silicon technology are leading to devices with deep submicrometer dimensions or new applications such as thin‐film transistors for flat‐panel displays, flash memories, or power devices. Variations in silicon technology such as silicon on insulator, silicon–germanium alloys, or silicon carbide are briefly reviewed.
Silk
Authors: Kaplan David L. , Mello Charlene , Fossey Stephen , Arcidaicono Steven 
Published: July 2004

AbstractSilks are naturally spun fibrous proteins most often associated with the silkworm and spiders. Silk fibers are unusual in combining strength, toughness, and compressibility. The proteins are characterized primarily by a β‐sheet secondary structure consisting of a highly crystalline region as well as regions of lower crystallinity. Silkworm cocoon fibers have been used in textiles for thousands of years. Spider silk, of which there are many different types, has not been domesticated. Water‐soluble silk proteins are synthesized and stored in the silk glands until spun into fibers, at which point they become insoluble in water. The spinning process is regulated by the organism and involves the extrusion of the soluble silk in a liquid crystalline state through spinnerets. Silks are stable to approximately 230°C. Membranes have been formed from silks that provide a useful means to explore secondary structure and to entrap enzymes. Worldwide production of silkworm silk for textiles is expected to increase. Future applications depend on the success of biotechnology to provide adequate production levels of specifically tailored silk compositions.
Silver and Silver Alloys
Authors: Etris Samuel F. 
Published: July 2004

AbstractThe 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.
Fluorine Compounds, Inorganic, Silver
Authors: Meshri Dayal T. 
Published: July 2004

Abstract
Four binary fluorides, two mixed valent fluorides, and several fluorocomplexes of silver are known. Both silver fluoride and silver difluoride, used as fluorinating reagents, are commercially available, as are silver hexafluoroantimonate, silver hexafluorophosphate, silver tetrafluoroborate, and silver trifluoroacetate. Silver fluoride is also used in batteries and as an antimicrobial agent; the silver fluorocomplexes are used primarily in organic synthesis.
Simultaneous Heat and Mass Transfer
Authors: Wenzel Leonard A. 
Published: July 2004

Abstract
In process operations where material is transferred between phases, usually between liquid and vapor phases, the transport process may be described in terms of heat transfer and mass transfer. When both expressions are developed and handled simultaneously, the resulting equations show that heat and mass transfer affect each other. Equations applied to humidification and dehumidification processes are presented. These expressions could equally well be applied to drying, evaporation, or crystallization processes. The conceptual design of counterflow cooling towers or dehumidification towers is discussed, as are the mechanical and operating features of these columns, costs, and environmental impacts. In all of these processes the air–water system is usually of concern. Thus the properties of moist air are developed and displayed on psychrometric charts.
Size Enlargement
Authors: Capes C. Edward , Darcovich K. 
Published: July 2004

AbstractSize enlargement concerns those processes which bring together fine powder particles into larger masses to improve the properties of the powders. Many diverse industries benefit from size enlargement processes. Examples discussed herein include fertilizer granulation, iron ore pelletization, tablet feeds for pharmaceuticals, instant food products, and the processing of mineral and chemical products.This article considers primarily those processes in which the creation of coarse granular material from fines is the objective. The characteristics of individual agglomerates are important only in their effect on the properties of the bulk granular product.Following initial discussion of particle‐bonding mechanisms and the theory and measurement of agglomerate strength, size enlargement processes and equipment, including principal design parameters, are described. These processes are considered on the basis of the principal mechanism used to bring the particles together into agglomerates. The categories used are agglomeration by tumbling and other agitation methods, pressure compaction and extrusion methods, heat reaction, fusion, and drying methods, and agglomeration from liquid suspensions by competitive wetting.
Size Measurement of Particles
Authors: Trottier Remi , Kaye Brian 
Published: July 2004

AbstractThe size distribution of particles is of importance to a wide variety of particulate systems in the chemical process industries. The compacting and sintering behavior of metallurgical powders, flow characteristics of granular materials, hiding power of paint pigments, and the combustion efficiency of coal and sprayed liquids all depend on particle size. The various means of data representation in particle size measurements are defined and sampling procedures are presented. Methods of size measurement ranging from the historical yet still useful sieving, through the use of modern instrumentation such as laser diffraction equipment and optical counters, are discussed.
Sodium Sulfates
Authors: Butts David 
Published: July 2004

Abstract

Sodium sulfate, Na
2
SO
4
, is principally used as a filler in soaps and detergents and in the manufacturing process of kraft paper. These uses consume about 65% of the world's production. It is also used in glassmaking, in cattle‐feed mixes, in cellulose sponge, in metallurgical refining, and as a cement and plaster hardener. Both sodium sulfate and sodium bisulfate, NaHSO
4
, are used to adjust the pH of various solutions and to dilute certain dyes. Sodium bisulfate is a mild acid safe for household cleaning and where a mild acid is needed. About half of the sodium sulfate production is derived from naturally occurring salts and brines. The other half is produced as a by‐product in the manufacture of rayon, sodium dichromate, resorcinol, and silica pigments.
Sodium Hydroxide
Authors: Eggeman Tim 
Published: July 2004

Abstract

Sodium Hydroxide (Caustic Soda) falls in a group of commodity chemicals which also includes chlorine, Cl
2
; sodium carbonate (soda ash), Na
2
CO
3
; potassium hydroxide (caustic potash), KOH; and hydrochloric acid (muriatic acid or anhydrous), HCl. Chlorine and caustic soda are the two most important products in this group, ranking among the top ten chemicals in the United States. The applications for chlorine and the alkalies are so varied that there is hardly a consumer product which is not dependent on one or both of them at some manufacturing stage. Chlorine and caustic soda are coproducts of the electrolysis of aqueous solutions of sodium chloride, NaCl (commonly called brine). Conversion of aqueous NaCl to Cl
2
and NaOH is achieved in three types of electrolytic cells: the diaphragm cell, the membrane cell, and the mercury cell. The distinguishing feature of these cells is the manner by which the electrolysis products are prevented from mixing with each other, thus ensuring proper purity. Solution mining of salt and the availability of asbestos resulted in the dominance of the diaphragm process in North America, whereas solid salt and mercury availability led to the dominance of the mercury process in Europe. Japan imported its salt in solid form and, until the development of the membrane process, also favored the mercury cell for production. Sodium hydroxide, NaOH, mol wt 39.998, is a brittle, white, translucent crystalline solid. Because of its corrosive action on all human body tissue, it is also known as caustic soda. Aqueous solutions of caustic soda are highly alkaline. Hence caustic soda is primarily used in neutralization reactions to form sodium salts. Reactions of NaOH with natural products are complex. They include solubilization of cotton in rubber reclaiming, cotton scouring, refining of vegetable oils, and removal of lignin and hemicellulose in the Kraft pulping process. The only caustic soda production process besides electrolysis is the soda–lime process, practiced by companies which do not participate in the chlorine market. Three forms of caustic soda are produced to meet customer needs: purified diaphragm caustic (50% Rayon grade), 73% caustic, and anhydrous caustic. Caustic soda is classified as a corrosive material by the DOT, and it has a marked corrosive action on all body tissue. Inhalation of the dust or mist can cause damage to the upper respiratory tract. During handling, all persons should wear proper protective clothing, safety goggles or a full face shield, rubber gloves, boots, and a caustic‐resistant apron or suit. Disposal of waste or spilled caustic soda must be carried out by properly trained personnel.
Sodium Bromide
Authors: Kust Roger N. 
Published: July 2004

Abstract
Sodium bromide is the most common and available alkali bromide, occurring in both the anhydrous and dihydrate forms. The anhydrous salt is hygroscopic but not deliquescent and has a very high solubility in water. Commercial quantities are prepared from bromine and sodium hydroxide solutions. Sodium bromide is moderately toxic by ingestion and can affect the gastrointestinal and central nervous systems and the skin. A primary use of sodium bromide is as a heavy, clear brine fluid in completing and working over oil and gas wells. Another principal use of sodium bromide is in industrial wastewater treatment. When activated with hypochlorites or isocyanurates sodium bromide becomes a very effective biocide. Sodium bromide is used in the photographic industry, has some application as a cocatalyst, as a wood preservative, and as a pharmaceutical.
Sodium Iodide
Authors: Merrell Philip H. , Peters Elizabeth M. 
Published: July 2004

Abstract
Sodium iodide, its occurrence, physical properties, manufacture, economic aspects, and uses are described. It is produced by acid–base reaction yielding no by‐products and is stored on the basic side to retard oxidation.
This important halide salt is used in medicine as a detector for such devices as computer‐assisted tomography scans and positron emission tomography. It tends to form the dihydrate at temperatures below 65°C and is deliquescent, which makes it much different in handling characteristics from its potassium counterpart.
Soil Chemistry of Pesticides
Authors: Kearney Philip C. , Shelton Daniel R. , Koskinen William C. 
Published: July 2004

AbstractPesticide sales have held steady at about 500,000 t annually in the United States since the 1970s. Groundwater monitoring studies show that a small percent of a few compounds are actually being detected in the parts per billion range. The degradation and retention processes in soils determine the amounts and types of pesticides that leach into groundwater. The principal reactions that degrade pesticides in the environment occur primarily on or in soils. Soil microorganisms catalyze the enzymatic oxidation, reduction, and hydrolysis of most pesticides. Chemical reactions in soils yield many of the same products as the biochemical reactions mediated by soil microorganisms. Sorption processes bind pesticides and prevent movement either within or outside the soil matrix. Soil organic matter is the principal sorbent for most organic pesticides. Pesticides are sorbed to soil particles by van der Waals forces, hydrogen bonding, dipole–dipole interactions, ion exchange, and covalent bonding mechanisms. Development of new active pesticides, biotechnology, sustainable agricultural practices, and evolving regulations will lower the future amounts of pesticides detected in soil and water.