Hughes, C. M. M., see Easton

Although many indigoid dyes have been synthesized, only indigo [482-89-3] itself (45) is of any importance today. Indigo is the blue used almost exclusively for dyeing denim jeans and jackets and is held in high esteem because it fades in tone to give progressively paler blue shades.  [c.280]

This molecular multilayer is then capped with a cathode to complete the device. The HTL and ETL have high mobilities for holes and electrons, respectively, but very low mobilities for the oppositely charged carrier. When an electric field is appHed to this device, holes will move through the HTL to the HTL—EM interface and electrons will move through the ETL to the ETL—EM interface. These carries then form a bound state exciton, and subsequentiy recombine in the EM, leading to efficient light emission. Pot efficient recombination at the emitter site, the emitter molecule should have a HOMO higher than that of the HTL and a LUMO lower than that of the ETL (53).  [c.243]

U.S. Pat. 2,912,439 (Nov. 10, 1959), R. H. Hasek andj. E. Hardwicke (to Eastman Kodak Co.).  [c.118]

Acrolein" in ECT 1st ed., VoL 1, pp. 173—175, by R. L. Hasche, Tennessee Eastman Corporation in ECT 1st ed SuppL 1, pp. 1—18, by H. R. Guest and H. A. Stansbury, Jr., Union Carbide Chemicals Company "Acrolein and Derivatives" in ECT 2nd ed., Vol. 1, pp. 255—274, by H. R. Guest, B. W. Kiff, and H. A. Stansbury, Jr., Union Carbide Chemicals Company in ECT 3rd ed., Vol. 1, pp. 211—291 by L. G. Hess, A. N. Kurtz, and D. B. Stanton, Union Carbide Corporation.  [c.129]

Plastic materials represent less than 10% by weight of all packagiag materials. They have a value of over 7 biUion including composite flexible packagiag about half is for film and half for botties, jars, cups, tubs, and trays. The principal materials used are high density polyethylene (HDPE) for botties, low density polyethylene for film, polypropylene (PP) for film, and polyester for both botties and films. Plastic resias are manufactured by petrochemical companies, eg. Union Carbide and Mobil Chemical for low density polyethylene (LDPE), Solvay for high density polyethylene, Himont for polypropylene, and Shell and Eastman for polyester.  [c.451]

MAK is used as a high soHds coating solvent (163) and in fragrances. It is available in the United States from Eastman (Kingsport, Teimessee), International Chemical Group (La Mesa, California) (47), and Union Carbide (South Charleston, West Virginia), and was priced at 1.36/kg in October 1994.  [c.493]

The high cost of coal handling and preparation and treatment of effluents, compounded by continuing low prices for cmde oil and natural gas, has precluded significant exploitation of coal as a feedstock for methanol. A small amount of methanol is made from coal in South Africa for local strategic reasons. Tennessee Eastman operates a 195,000-t/yr methanol plant in Tennessee based on the Texaco coal gasification process to make the methyl acetate intermediate for acetic anhydride production (15).  [c.278]

In Estonia, most of the rich oil shale, 209 L/1 kukersite, is burned as a soHd fuel to produce electric power (37). The kukersite, although technically an oil shale, is actually similar to a high ash, low grade coal (qv) ideally suited for this use.  [c.354]

Eastman Chemical has utilized a unique, high temperature solution process for propylene polymerization. Polymerization temperatures are maintained above 150°C to prevent precipitation of the isotactic polypropylene product in the hydrocarbon solvent. At these temperatures, the high rate of polymerization decreases rapidly, requiring low residence times (127). Stereoregularity is also adversely affected by high temperatures. Consequentiy, the  [c.414]

Acetaldehyde can be used as an oxidation-promoter in place of bromine. The absence of bromine means that titanium metallurgy is not required. Eastman Chemical Co. has used such a process, with cobalt as the only catalyst metal. In that process, acetaldehyde is converted to acetic acid at the rate of 0.55—1.1 kg/kg of terephthahc acid produced. The acetic acid is recycled as the solvent and can be isolated as a by-product. Reaction temperatures can be low, 120—140°C, and residence times tend to be high, with values of two hours or more (55). Recovery of dry terephthahc acid follows steps similar to those in the Amoco process. Eastman has abandoned this process in favor of a bromine promoter (56). Another oxidation promoter which has been used is paraldehyde (57), employed by Toray Industries. This leads to the coproduction of acetic acid. 2-Butanone has been used by Mobil Chemical Co. (58).  [c.488]

PCT has low moisture uptake and is not affected by changes in humidity as is nylon. However, as with all high melting polyesters, care must be taken to dry the polymer chip thoroughly before melting. PCT has both a high melting point (285—290°C) and a high melt viscosity. Processing temperatures must be over 300°C, which is high for non-LCP polyesters. The combination of properties can lead to thermal and thermooxidative degradation and severe IV drop during mol ding, giving brittle parts (146). The presence in the molecule of two tertiary hydrogen atoms both in a P-position to the ester group is possibly a source of stmctural weakness here. Several patents have appeared on the use of extra additives, antioxidants, and other polymer stabilizers to overcome this problem (147—149). Another patent describes copolymers (150) with better crystallization rates and mol ding properties, and two patents have appeared on the use of terephthaUc acid in place of dimethyl terephthalate in the production of the polymer, both in batchwise (151) and continuous polymerization processes (152). The new family of PCT resins was originally called Ektar, but has been re-designated Thermx since the reorganization of Eastman Chemicals into an independent corporation.  [c.299]

Sodium selenite has also been incorporated into styrene—butadiene mbber and used in a pellet form which results in the slow release of selenium into water. These pellets have been placed in lakes in Sweden which have fish contaminated with mercury owing to high levels of that element in the water. The selenium released by the pellets reacts with mercury to form insoluble, heavy mercury selenide which setties to the lake bottom and removes mercury from the ecosystem (126).  [c.338]

The manufacture of silver nitrate for the preparation of photographic emulsions requires silver of very high purity. At the Eastman Kodak Company, the principal U.S. producer of silver nitrate, 99.95% pure silver bars are dissolved in 67% nitric acid in three tanks coimected in parallel. Excess nitric acid is removed from the resulting solution, which contains 60—65% silver nitrate, and the solution is filtered. This solution is evaporated until its silver nitrate concentration is 84%. It is then cooled to prepare the first crop of crystals. The mother Hquor is purified by the addition of silver oxide and returned to the initial stages of the process. The cmde silver nitrate is centrifuged and recrystallized from hot, demineralized water. Equipment used in this process is made of ANSI 310 stainless steel (16).  [c.89]

J. Higashi, A. D. Eastman, and R. W. Parry, Inorg. Chem. 21, 716 (1982).  [c.269]

Although cellulose acetate remains the most widely used organic ester of cellulose, its usefulness is restricted by its moisture sensitivity, limited compatibihty with other synthetic resins, and relatively high processing temperature. Cellulose esters of higher aUphatic acids, and C, circumvent these shortcomings with varying degrees of success. They can be prepared relatively easily with procedures similar to those used for cellulose acetate. Mixed cellulose esters containing acetate and either the propionate or butyrate moieties are produced commercially in large quantities by Eastman Chemical Co. in the United States (Table 2). Bayer AG discontinued the production of mixed esters at Leverkusen in Germany in mid-1987 citing poor economics as the reason for the closing.  [c.249]

Several plants use the Texaco partial oxidation gasifier developed as a modification of Texaco s oil consuming partial oxidation process. Pulverized coal falls through the reactor at high pressure and temperature to produce the gas which is then cleaned. The ratio of carbon monoxide to hydrogen can be adjusted by the water gas shift reaction as needed for a variety of chemical intermediates. This design was used in a plant to make chemical intermediates for the Eastman-Kodak Co. in Kingsport, Tennessee. The Coolwater IGCC demonstration plant in Southern California used this gasifier to provide fuel gas for boilers for electric power generation or for gas turbines for combined cycle power generation. The plant was technically successful but not able to compete economically. The scmbbing system removes a very high amount of the sulfur in the coal (95,96).  [c.235]

In contrast, the copolyester—ether block copolymer TPE are relatively expensive with high performance characteristics. These materials exhibit a two-phase morphology in which the hard crystalline segments made from polyester act as thermally reversible cross-links. The elastomeric character of the polymer arises from the amorphous soft polyether ester segments. They are produced by a melt-transesterification polymerization process and can be processed by conventional techniques such as injection, blow, transfer, or rotational molding. Important commercial products are produced by Du Pont (Hytrel), Eastman Kodak (Ecdel), General Electric (Lomod), and Hoechst Celanese (Riteflex). U.S. copolyester—ether consumption in 1988 was 12,000 t. Their most important uses are in wire cable materials (eg, the coiled stretch telephone cords), injection-molded articles (eg, small mechanical parts), and high pressure hoses (87).  [c.186]

Eate studies on eighteen dyes were done by the Water Engineering Research Laboratory of the USEPA (49). The objective was to determine the partitioning of water-soluble azo dyes in the activated sludge process (ASP). Specific azo dyes were spiked at 1 and 5 mg/L to pilot-scale treatment systems with both hquid and sludge samples collected. Samples were analyzed by high pressure Hquid chromatography and an uv—vis detector. Mass balance calculations were made to determine the amount of the dye compound in the waste activated sludge (WAS) and in the activated sludge effluent (ASE). Of the eighteen dyes studied, eleven compounds passed through the ASP substantially untreated, four were significantly adsorbed into the WAS, and three were apparently biodegraded.  [c.384]

An appreciation of the extent to which invertebrate species may be exposed to such chemicals comes from considering the effects of complex mixtures. In the North Atlantic ecosystem alone, hundreds of pollutant chemicals have been identified. These include metals, synthetic and chlorinated organics and polycyclic aromatic hydrocarbons. Over 300 aromatic hydrocarbons have been detected in some regions of the Chesapeake Bay, and high concentrations of PCBs have been  [c.52]

In a business where oxygen plants play a key role in the eost of the end produet, Western Mining needs high proeess effieieneies. This prompted the eompany to seleet a eustom-built eentrifugal eompressor and turboexpander.  [c.448]

Around the turn of the century, one of the most obvious effects of industry on the environment was the complete destruction of vegetation downwind from copper, lead, and zinc smelters. This problem was caused by the smelting of the metallic sulfide ores. As the metal was released in the smelting process, huge quantities of sulfur were oxidized to SOj, which was toxic to much of the vegetation fumigated by the plume. Present smelting systems go to great expense to prevent the uncontrolled release of SO2, but in many areas the recovery of the ecosystem will take years and possibly centuries.  [c.88]

There is considerable species variability with respect to damage to vegetation by any specific pollutant. There is also great geographic variability with respect to where these species grow naturally or are cultivated. Because of this, it is possible that in a jurisdiction none of the species particularly susceptible to damage by low levels of pollution may be among those indigenous or normally imported for local cultivation. As an example, the pollution level at which citrus trees are adversely affected, while meaningful in setting air quality standards in California and Florida, is meaningless for this purpose in Minnesota and Wisconsin. In like manner, a jurisdiction may take different viewpoints with respect to indigenous and imported species. It might set its air quality standards low enough to protect its indigenous vegetation even if this level is too high to allow satisfactory growth of imported species. Even if a particularly susceptible species is indigenous, it may be held in such low local esteem commercially or aesthetically that the jurisdiction may be unwilling to let the damage level of that species be the air quality standard discriminator. In other words, the people would rather have that species damaged than assume the cost of cleaning up the air to prevent the damage. This same line of reasoning applies to effects on wild and domestic animals.  [c.376]

Figure C2.17.12 depicts a comparison between experimentally detennined exciton energies and those predicted by the Bms model, for CdSe nanocrystals. Given the level of approximation, the agreement is surjDrising. Nonetheless, the simple theory clearly overestimates the energies for the smallest crystallites. Recent work, both experimental and theoretical, has shown that the main deficiency of the quantum confinement model is that it fails to include molecular-level detail. For example, the Bms model assumes that the confining potential is spherically symmetric and infinitely high. High-resolution electron microscopy studies [162] as well as theoretical calculations [163] have suggested that the lattice stmcture and facets of nanocrystals lower the particle symmetry leading to intrinsic shifts in the confinement energies. Dielectric spectroscopy [164], as well as Stark absorjDtion spectroscopy [165, 166] Figure C2.17.12 depicts a comparison between experimentally detennined exciton energies and those predicted by the Bms model, for CdSe nanocrystals. Given the level of approximation, the agreement is surjDrising. Nonetheless, the simple theory clearly overestimates the energies for the smallest crystallites. Recent work, both experimental and theoretical, has shown that the main deficiency of the quantum confinement model is that it fails to include molecular-level detail. For example, the Bms model assumes that the confining potential is spherically symmetric and infinitely high. High-resolution electron microscopy studies [162] as well as theoretical calculations [163] have suggested that the lattice stmcture and facets of nanocrystals lower the particle symmetry leading to intrinsic shifts in the confinement energies. Dielectric spectroscopy [164], as well as Stark absorjDtion spectroscopy [165, 166]
In the 1950s resist systems with substantially improved processing characteristics were developed. The first commercially available member of this class, KPR, was introduced in 1953 by Eastman Kodak. Originally targeted for printing appHcations, KPR was used in the fabrication of circuit boards and semiconductor devices later in the decade. This material is a cross-linking system based on the photodimerization of poly(vinyl cinnamate) chains. Pendant carbon-carbon double bonds on adjacent polymer strands undergo photocyclization to form a cross-linked, insoluble network in exposed areas (Fig. 4). Although poly(vinyl cinnamate) is intrinsically photoactive, its electronic absorption peaks neat a wavelength of 290 nm, and absorbs only weakly at wavelengths longer than 350 nm, where the lamps commonly used in exposure tooling (eg, a high pressure mercury arc) show strong emission. Its spectral sensitivity can be extended to longer wavelengths by addition of an appropriate absorbing dye. The dye is beheved to act as a triplet photosensitizer, transferring excitation energy to a cinnamate acceptor. The intermediate triplet cinnamate adds to a ground state cinnamate to form a binadical species, which closes to produce the final cross-linked cycHc stmcture.  [c.115]

Aside from dye-based cells, a good deal of study has been devoted to photovoltaic effects in polymer-based devices. Single-layer sandwich-type devices composed of aluminum—polyphenylenevinylene—ITO have been fabricated with solution-cast polymer layers of - 0.5//. These devices display quantum efficiencies of up to 5% (power efficiencies of 0.07%), though the efficiency decreases at high illumination levels (80). Other single-layer polymer devices fabricated with polyacetylene show similar efficiencies (81). To obtain optimum efficiency in a photovoltaic device, it is necessary to dissociate the exciton before the charges recombine to generate a photon, and a resulting loss in device efficiency. Multilayer devices consisting of separate donor and acceptor layers generate substantial improvement in device efficiency by faciUtating dissociation of the electron-hole pair. In these two-layer devices, excitons that diffuse to the D-A interface are separated (the electron going to the acceptor), and the charges can then be swept on to the electrodes through their respective layers.  [c.245]

Production Routes. The capacity for manufacturing acetic acid through methanol carbonylation grew from almost nothing in 1969 to 80% of actual plant operational capacity in 1988 for the United States. Almost all new plants use the low pressure carbonylation route. In 1989, Eastman Chemical s plant at Kingsport, Term., had the abiUty to coproduce acetic acid in excess of 68 t/yr. The plant produces both acid and anhydride from coal by carbonylation of methyl acetate (51). American production of acetic acid from butane Hquid-phase oxidation at the Hoechst-Celanese plant at Pampa, Tex., is at a norninal 1989 capacity of 250 kg/yr. Eavorable prices for the butane raw material and high efficiency of the plant design favor this production method. Acetaldehyde oxidation is extensively employed in Europe where acetaldehyde is produced from the palladium—copper-cataly2ed oxidation of ethylene. Process yields for acetic acid on the order of 90% may be obtained. Sophisticated engineering and design gives the acetaldehyde route much of its c omp etitivene s s.  [c.69]

Ain pollution, as defined by textbooks published in the 1970s and 1980s, is any atmospheric condition in which substances are present in concentrations high enough above thein normal ambient levels to produce a measurable effect on humans, animals, vegetation, or materials. This definition is deficient, however, because it does not include the so-called greenhouse or o2one-depleting gases which have the potential to alter the global climate and hence the global ecosystem. (The effects of these gases on humans, animals, vegetation, or materials have not been, and may never be, observed.) Therefore, in an attempt to be more comprehensive, the following definition is offered air pollution is the presence of any substance in the atmosphere at a concentration high enough to produce an objectionable effect on humans, animals, vegetation, or materials, or to significantly alter the natural balance of any ecosystem. Substances can be soHds, Hquids, or gases, and can be produced by anthropogenic activities or natural sources. In this article only nonbiological material is considered and the discussion of airborne radioactive contaminants is limited to radon [10043-92-2] (see Helium group, gases), which is discussed in the context of indoor air pollution.  [c.366]

Flame-Resistant Fibers. Acryhcs have reasonably good flame resistance compared to cotton and regenerated ceUulosic fibers. In addition, acryhcs tend to chat when burning rather than forming melts as do polyesters and nylons. Additional flame resistance is requited for certain end uses, such as children s sleepwear, blankets, carpets, outdoor awnings, and drapery fabrics. This can be achieved by copolymetizing acrylonitrile with halogen-containing monomers such as vinyl chloride, vinyl bromide, and vinyUdene chloride. ModacryUcs ate used where a high resistance to burning is requited. In such fibers the level of halogen-containing monomers may be over 50%, as in Dynel, one of the earliest modacryhcs. This fiber, no longer produced, was 50/60 acrylonitrile—vinyl chloride copolymer. Tennessee Eastman s Vetel, an acrylonitrile—vinyUdene chloride copolymer, has also been discontinued.  [c.284]

The results of one such study are summarized in Table 1 (4). Each ecosystem on the earth is considered in terms of area, mean net carbon production per year, and standing biomass carbon, ie, carbon contained in biomass on the earth s surface and not including carbon stored in biomass underground. Forest biomass, produced on only 9.5% of the earth s surface, contributes more than any other source to the total net carbon fixed on earth. Marine sources of net fixed carbon also are high because of the large area of earth occupied by water. However, the high turnover rates of carbon in the marine environment result in relatively small steady-state quantities of standing carbon. The low turnover rates of forest biomass make it the largest contributor to standing carbon reserves. Forests produce about 43% of the net carbon fixed each year and contain over 89% of the standing biomass carbon of the earth tropical forests are the largest sources of these carbon reserves. Temperate deciduous and evergreen forests also are large sources of biomass carbon, followed by the savanna and grasslands. Cultivated land is one of the smaller producers of fixed carbon and is only about 9% of the total terrestrial area of the earth.  [c.10]

Ketenes" in ECT 1st ed., VoL 8, pp. 109—113, byj. R. CaldweU, Tennessee Eastman Co. "Ketenes and Related Substances" in ECT2nd ed., VoL 12, pp. 87—100, by R. H. Hasek, Tennessee Eastman Co. in ECT 3rd ed., Vol 13, pp. 874—893, by R. H. Hasek, Tennessee Eastman Co.  [c.482]

Liquid crystalline thermotropic polyesters were discovered independently in several places during the late 1960s and eady 1970s. Notably work at Carbomndum Corporation (13—15), Eastman (16,17), and Du Pont (18—21) led to the cmcial discovery that certain aromatic copolyesters derived either from aromatic hydroxyacids or by reaction of a diacid with an aromatic diol, could exist in a mesophase or Hquid crystal state well below their thermal decomposition temperature. In fact, work on all-aromatic high melting polyesters was carried out at ICl Eibres (Harrogate, England) during 1962—1963 thermotropic behavior (birefringent melt) was actually observed in 1963, but at this eady date its tme significance was not appreciated (22). In the mid-1970s, during work on a melt-spun high modulus aH-aromatic polyester fiber at Celanese Corporation, the unique properties of aH-aromatic polyesters derived from 6-hydroxy-2-naphthoic acid [16712-64-4] (HNA) were discovered (23). These materials were readily processible and Hquid crystalline, yet had moderate melting points, ie, a soHd-nematic mesophase transition, in the region 240—300°C. The copolyester of HNA and 4-hydroxybenzoic acid [99-96-7] (HBA) became the basis of the Vectra series of Hquid crystal polymers (LCP). Meanwhile, the original Carbomndum work had led via licensing arrangements to commercialization of other high melting thermotropic polyesters, firstiy by Sumitomo (Japan) and later by Dart Corporation (now Amoco) in the United States under the trade name Xydar. Du Pont has entered the field with the Zenite range of LCPs based on naphthalene-2,6-dicarboxyHc acid.  [c.293]

Commercially, the most important reaction of PTME glycols is the reaction with diisocyanates. Reaction with an excess of diisocyanate yields a prepolymer having isocyanate end groups, which can further react with short-chain diols or amines to give high molecular weight polyurethanes or polyurethane ureas (122,123). Some of these prepolymers are also available commercially. Typical examples are Adiprene and Vibrathane from Uniroyal, Airthane from Air Products Corporation, Conathane from Conap, and Hyprene from Mitsui Toatsu. These prepolymers can be chain-extended (cured) to high molecular weight polyurethanes with aUphatic diols or to polyureas with diamines, or they can be cross-linked by reaction with moisture (124). High molecular weight, fully cured PTMEG polyurethanes are also commercially available as thermoplastic polyurethanes (TPUs). Examples are certain grades of PeUethane (Dow Chemical Corporation), Estane (BE Goodrich), and Texin (Bayer/Miles Corporation). Thermoplastic polyesters based on PTMEG are other types of important commercial elastomer. They are generally based on PTMEG soft segments and terephthalate hard segments with aUphatic short-chain diols, such as ethylene glycol, 1,4-butandiol, or cycloaUphatic diols (123—139). Examples of such polyester elastomers are Hytrel (Du Pont), Pelprene (Toyobo), Ecdel (Eastman Chemicals), Lomod (General Electric), and Arnitel (DSM). PTME is also the soft segment in an elastomeric polyamide, which contains nylon-type hard segments (Pebax, by Elf Atochem). The chemical and physical properties of thermoplastic elastomers have been reviewed (140).  [c.361]

A summary of the U.S. economic perspective, approximate production volumes, average retail prices, and leading producers is given in Table 4. Other commercial products include diallyl dimethyl ammonium chloride [7398-69-8] produced by CPS Chemical Company di(hydrogenated tall ow)a1ky1 dimethyl ammonium methosulfate [61789-81-9] produced by Akzo Nobel and High Point Chemical Corporation and tetrabutylammonium bromide [1643-19-2] produced by Zeeland Chemical. The leading producers of phase-transfer quaternaries are Eastman Kodak Company, Hexcel Corporation, RSA, Chemical Dynamics Corporation, Lindan Chemicals, Henkel Corporation, and Akzo Nobel. From 2,300 to 11,300 metric tons of quaternaries were used as phase-transfer catalysts during 1991 (233). The principal producers of perfluorinated quaternaries are Ciba, 3M Specialty Chemicals, and E. I. du Pont de Nemours Company, Inc.  [c.382]

Preventing Stressful High Temperatures Over Long Periods. For the long term (>l-2 d), simply preventing mortaUty is insufficient for protecting aquatic species. AH of the physiological functions normally performed must be carried out to maintain healthy individuals that are capable of competing in the natural ecosystem. An aggregate measure, growth rate, has proved useful as an integrator of all physiological functions and some behavioral ones, eg, feeding rate. Growth occurs only if all other metaboHc demands are being met and when sufficient food energy is left over for adding biomass. Typically, many physiological functions of well-fed, cold-blooded organisms proceed optimally over a temperature range in which growth rate is maximal (Fig. 4). Above the temperatures of maximum growth rate, the rate typically declines steeply to a temperature of 2ero growth, which often occurs 1—2°C below the temperature at which direct mortaUties begin. Intuitively, the healthy fish becomes unhealthy as the long-term temperatures it experiences rise from those that yield maximum growth to that which stops growth. Alternative methods for calculating the upper danger level have been proposed, but each suggests that a long-term decline of growth rate below ca 75% of maximum at high temperatures is unduly risky (13,15).  [c.475]

Thermal heterogeneity of the environment, thermal optima for organism growth rates, and behavioral temperature selection are being evaluated in ways that are useful for predicting ecosystem effects of thermal alterations (18). Thermal-niche concepts can be used to identify critical habitats for important species in ways that focus the potential influences of power-station discharges (20,21). For example, striped bass (Morone saxatilis an East Cost species introduced on the West Coast and in freshwater reservoirs, partitions a water body in summer along thermal gradients among its age or si2e classes. Young bass prefer and grow optimally at high temperatures near 24—26°C, subadults prefer ca 22°C, and mature adults select temperatures of 20°C or less. Thermal discharges may benefit growth rates and survival of juveniles, but the adults face a different prospect. Forced to cool water in summer by their genetically based temperature preferences, they may find this habitat severely restricted by thermal additions or compromised by simultaneous depletion of dissolved oxygen as a result, in part, of decomposition of thermally stimulated plankton production. Overcrowding in limited thermal refuges that have sufficient dissolved oxygen has led to starvation, high disease incidence, and abnormally high fishing susceptibiUty, all of which cause high numbers of deaths.  [c.476]

A different approach was taken in Kodacolor film, introduced by Eastman Kodak Co. in 1942. The couplers were ballasted but, instead of having hydrophilic functional groups, were dissolved in a sparingly water-soluble oily solvent. This oily phase was then dispersed by high agitation into a gelatin solution as fine droplets less than one micrometer in diameter. Kodacolor film is negative working, and was designed to be printed onto a companion color paper, which because it is also negative working, produces a positive color print. The whole system is known as the negative—positive process.  [c.471]

Suppliers. Cyanine dyes are used primarily for specialty purposes photographic sensitizers and desensitizers, laser dyes, infrared imaging, and certain medicinal appHcations. Because of this, their manufacture is limited to significantly smaller quantities than for fabric dyes or other widely used coloring agents. However, the photographic, laser, and medicinal uses place high demands on the degree of purity required, and the reproducibiHty of synthetic methods and purification steps is very important. SuppHers of cyanine dyes include manufacturers of other specialty organic and photographic chemicals Aldrich Chemical Company (Milwaukee, Wis.), Eastman Organic Chemicals (Rochester, N.Y.), Japanese Institute for Photosensitizing Dyes (Okayama, Japan), Molecular Probes (Eugene, Oreg.), NKDyes (Japan), Pfaltz and Bauer (Stamford, Coim.), and Riedel deHaen (Kadsmhe, Germany). More importantiy, these firms provide sources of generally usefiil reagents which, in two or three synthetic steps (12), lead to many of the commonly used cyanine dyes.  [c.400]

Sensitizing dyes aie used primarily for specialty purposes photographic sensitizers, electrophotographic sensitizers, laser dyes, infrared (optical disk, etc) imaging, and certain medicinal appHcations. Because of this, their manufacture is limited to significantly smaller quantities than for fabric dyes or other widely used coloring agents. However, the photographic, laser, and medicinal uses place high demands on the degree of purity required, and the reproducibihty of synthetic methods and purification steps is very important. SuppHers of cyanine dyes include manufacturers of other specialty organic and photographic chemicals Aldrich Chemical Co. (Milwaukee, Wisconsin), Eastman Fine Chemicals (Rochester, New York), Japanese Institute for Photosensitizing Dyes (Okayama, Japan), Molecular Probes (Eugene, Oregon), NKDyes (Japan), Pfaltz and Bauer (Stamford, Coimecticut), Riedel deHaen (Kadsmhe, Germany), and H. W. Sands. More importandy, these firms provide sources of generally usefiil reagents that, in two or three synthetic steps, lead to many of the commonly used sensitizers.  [c.438]

Most polyesters (qv) are based on phthalates. They are referred to as aromatic-aHphatic or aromatic according to the copolymerized diol. Thus poly(ethylene terephthalate) [25038-59-9] (PET), poly(butyelene terephthalate) [24968-12-5] (PBT), and related polymers are termed aromatic-aHphatic polyester resins, whereas poly(bisphenol A phthalate)s are called aromatic polyester resins or polyarylates PET and PBT resins are the largest volume aromatic-aHphatic products. Other aromatic-aHphatic polyesters (65) include Eastman Kodak s Kodar resin, which is a PET resin modified with isophthalate and dimethylolcyclohexane. Polyarylate resins are lower volume specialty resins for high temperature (HDT) end uses (see HeaT-RESISTANT POLYAffiRS).  [c.267]

After almost 10 years of service, several pipes were removed because of restricted flow associated with accumulation of corrosion products and macrofouling (Figs. 6.17 and 6.20). The most heavily fouled sections contained unclarified river water and remained stagnant for as long as 30 days at a time. Eighteen months before removal of the pipes, parts of the system had been cleaned using high-pressure water jets. No failure had occurred. Wastage was nowhere deeper than about 0.030 in. (0.076 cm). However, small-diameter tubes were severely obstructed. Up to half the volume of obstructing material consisted of small tubelike organisms (Fig. 6.17).  [c.154]

Publication of Silent Spring by Rachel Carson in 1962 provided a warning of the dangers of the mass spraying of agricultural land with pesticides. The high incidence of dead and dying birds and hsh was immediately apparent in areas subjected to this practice, and humans in affected areas were also experiencing symptoms attributable to use of the pesticides. With the cessation of such eradication programmes, which in many cases had not brought about the benehts that had been claimed, it was assumed that the problem had disappeared. Indeed, the birds returned and sang again and hsh were once more found in the rivers. For two decades the world became complacent and concentrated on increasing the living standards of a minority of its population in the northern hemisphere. Motor traffic increased in cities, the network of motorways expanded and there was a massive growth in air traffic as world trade and both business and leisure travel expanded. Use of timber pulp for packaging and printing increased greatly, while the innovation of plastics has revolutionised our way of life. Together with the production and disposal of many thousands of different consumer goods, this has resulted, in less than half a century, in the production and release of several hundreds of thousands of synthetic chemicals and the release of abnormally high amounts of many natural chemicals in timber and mining wastes. Whether such release was into the atmosphere, onto land or into the rivers, it all eventually comes to rest in the aquatic ecosystem. Fish, as inhabitants of the rivers, lakes and oceans, inevitably receive the greatest exposures. In areas such as the Great Lakes, the North and Baltic Seas, situated close to areas of high industrial activity, with a relatively low water flow or where sedimentation can occur, fish can be subjected to extremely high exposures.  [c.27]

The use of inadiation or electron bombardment offers an alternative approach to molecular dissociation to the use of elevated temperamres, and offers a number of practical advantages. Intensive sources of radiation in the visible and near-visible are produced by flash photolysis, in which a bank of electrical capacitors is discharged tlrrough an inert gas such as ktypton to produce up to 10 joule for a period of about 10 " s, or by the use of high power laser beams (Eastham, 1986 (loc.cit.)). A more sustainable source of radiation is obtained from electrical discharge devices usually incorporating  [c.72]

High-purity compounds may be studied at liquid He temperatures to assess the sample s quality, as in Figure 2. Trace impurities give rise to spectral peaks, which can sometimes be identified by their binding energies. The application of a m -netic field for m netophotoluminescence can aid this identification by introducing extra field-dependent transitions that are characteristic of the specific impurity. Examples of identifiable impurities in GaAs, down to around 10 cm, are C, Si, Be, Mn, and Zn. Transition-metal impurities give rise to discrete energy transitions within the band gap. Peak shifts and splitting of the acceptor-bound exciton lines can be used to measure strain. In heavily Be-doped GaAs and some quantum two-dimensional (2D) structures, the Fermi edge is apparent in the spectra, and its position can be converted into carrier concentration.  [c.378]

The final article of the volume deals with the use of adsorption isotherms to determine surface area. The amount of gas adsorbed at a surface can be determined volumetrically, or occasionally gravimetrically, as a function of applied gas pressure. Total surface areas are determined by physisorbing an inert gas (N2 or Ar) at low temperature (77 K), measuring the adsorption isotherm (amount adsorbed versus pressure), and determining the monolayer volume (and hence number of molecules) from the Brunauer-Emmett-Teller equadon. This value is then converted to an area by multiplying by the (known) area of a physisorbed molecule. The method is widely applied, pardcularly in the catalysis area, but requires a high surface area of material (at least 1 m /gm) e.g., powders, porous materials, and large-area films. Selective surface areas of one material in the presence of another (e.g., metal particles on an oxide support) can sometimes be measured in a similar manner, but by using chemisorption where a strong chemical bond is formed between the adsorbed species and the substrate material of interest. Hydrogen is most commonly used for this, since by now it is known that for many metals it dissociates and forms one adsorbed H-atom per surface metal atom. From the measurement of the amount of hydrogen adsorbed and a knowledge of the spacing between metal atoms (i.e., a knowledge of the crystallographic surfaces exposed) the metal surface area can be determined.  [c.697]

See pages that mention the term Hughes, C. M. M., see Easton : [c.455]    [c.592]    [c.419]    [c.444]    [c.12]    [c.150]    [c.609]   
Advances in heterocyclic chemistry Vol.80 (2001) -- [ c.60 , c.261 ]

Advances in heterocyclic chemistry Vol.85 (2003) -- [ c.60 , c.261 ]