Extreme Thinness


Alternatively, you may call (800) 535-0202 (in Washington. D.C. and Alaska. (202) 479-2449) from 8 30 am - 7 30 pm Eastern Time.  [c.22]

The Jahn-Teller theorem [69] states that the nuclear configuration of any nonlinear polyatomic system in a degenerate electronic state is unstable with respect to nuclear displacements that lower the symmeti y and remove the degeneracy. A more rigorous formulation [71] is If the potential energy surface of a nonlinear polyatomic system has two or more branches that intersect at one point, then at least one of them has no extremum at this point. An example (the fixe case, [70]) is shown in Figure 20. Since the nuclear displacement lowers the energy of the system, the point of degeneracy becomes  [c.355]

The scheme below shows how the eastern and western parts of a corrin chromo-phore can be combined regioselectively. The western part has a more acidic enamine than the eastern part, whereas the imidic ester of the eastern part is more electrophilic.  [c.260]

Eye and skin contact should be avoided because of the adhesive s rapid tissue-bonding capabiUties. In case of eye or skin contact, the affected area should be flushed with copious amounts of water. Especially with eye contact, the bonded area should not be forced apart, since this will produce more damage than the initial bonding. Medical attention is recommended. Soaking in warm water will gradually weaken and release the bond. Contact through clothing may produce a rapid exotherm and the clothing involved should be flooded with water. Efforts to pull the involved clothing away may result in skin damage.  [c.178]

Such repositioning inevitably means reduced production volume, and for the first time this century production in the last decade has been below that a decade earUer (Eig. 9). Most capacity reductions have been in North America and especiaUy eastern Europe. This has been offset in part by capacity increases in the Ear East. Rayon is no longer a significant component of carpets, and has lost the disposable diaper coverstock business to cheaper and more easUy processed polypropylene. It has, however, gained share in health and hygiene products and is now a principal component of tampons worldwide.  [c.354]

Unsaturated polyesters derived from trimethylpentanediol are characterized by a low exotherm, low shrink curing, and a product that has good electrical properties and excellent hydrolytic stabiUty and chemical resistance (10,19,40,41). These unsaturated resins exhibit low viscosity, low density, and good glass—fiber or filler wetting (10,41). They are resistant to hydrolytic action, probably because of the protection of the ester linkage by the pendent methyl groups, and by virtue of the lesser number of ester groups in a given weight of material than would be afforded with lower molecular weight glycols (42). Chemically resistant appHcations where trimethylpentanediol-based unsaturated resins are used include reinforced polyester storage tanks and pipelines for hot, concentrated acids, some solvents, mild bases, hypochlorite solution, and ammonia (see POLYESTERS, UNSATURATEd).  [c.373]

A Grignard reagent is prepared by first adding magnesium and a partial charge of solvent to the reactor (11,12), followed by the addition of RX, iu the remaining solvent, to the reaction flask. Initiation should occur within the first 10 wt % addition of the RX mixture. Evidence for the initiation is a large exotherm. Many chemists look for turbidity or change of color, but this can be mislea ding if the agitation is strong enough to shear the magnesium. Until initiation has been confirmed, no more than 20 wt % of the RX charge should be added to the reactor. Otherwise, there is a risk of initiation after all of the RX has been added. This is especially dangerous, because the resulting exotherm could cause a release of the reactor contents iato the atmosphere, and possibly result iu a fire.  [c.393]

Formation of the Grignard Reagent. In the classical methodology for the start-up of a batch process (Fig. 1), magnesium turnings or chips are charged to vessel R-2. After thorough purging with an iaert gas, a portion of the solvent is then added, followed by a fraction of the haUde charge from vessel R-1. The chief hazard associated with the manufacture of Grignard reagents occurs at this stage ia connection with the difficulty ia initiating the reaction. If the addition of the hahde is continued before initiation, then the presence of excess hahde suddenly initiating generates such a large exotherm that the cooling system may be overwhelmed. This may result in a dangerous pressure buildup and a potential explosion.  [c.394]

Although acetylene production in Japan and Eastern Europe is stiU based on the calcium carbide process, the large producers in the United States and Western Europe now rely on hydrocarbons as the feedstock. Now more than 80% of the acetylene produced in the United States and Western Europe is derived from hydrocarbons, mainly natural gas or as a coproduct in the production of ethylene. In Russia about 40% of the acetylene produced is from natural gas.  [c.382]

A comparison of available resources and production shows that Germany, ranked second in resources, was ranked first in production in 1990. Indeed a number of central and eastern European countries are producing proved recoverable reserves at a rate that should lead to exhaustion of local deposits before the end of the twenty-first century. On the other hand, the massive Russian reserves could allow production for a much longer time.  [c.153]

Plants for briquette production exist in the eastern part of Germany, AustraHa, and India. German transport costs pet unit of heating value ate about 40% less for briquettes than for lignite.  [c.155]

When denser briquettes are used for carbonizing, the product has 10—12% volatile matter, up to 20% ash, and a heat value ca 25 MJ/kg (11, 000 Btu/lb). Overall yields for normal briquette carbonization are char 45%, tar 12.5%, and gas 130 m (4600 ft ) having a gross heating value of 8.4 MJ/m (225 Btu/ft ). The char was ca 30% above 20 mm, used for domestic and central heating 50% from 6—20 mm, used for gasification 30% less than 6 mm, used for steam generation and gasification. About 270 Lurgi Spblgas plants exist, mainly in Germany, AustraUa, India, and the Eastern European countries, and having a coal input of 10 t/d. Eluidized-bed and entrained carbonization of lignite have been studied but have not been commercialized (see Eluidization).  [c.158]

Tars can be hydrogenated to produce Hquid fuels. High hydrogen and low asphaltene, ie, benzene-soluble and pentane-iasoluble, contents are desirable. The central German brown coals are attractive for this reason. The tars from the eastern part of Germany require much lower pressures and less hydrogen per unit of product than do brown coals near Cologne, which can require pressures up to 71 MPa (700 atm) (see Petroleum).  [c.159]

More than 99% of timing in the United States occurs in the eastern half of the country in the west, sods are alkaline. In 1991, 16.4 x 10 tons of timing material was used in the United States, about half the amount used during the record year of 1976, when federal subsidies for timing were in effect. Fertili r Filler. Fertilizer-mixing plants use ground limestone as a filler. Unlike inert fillers, limestone and dolomite provide calcium and magnesium as plant nutrients and acid-neutralizing values to the mix. Dolomitic stone is preferred because it is less reactive than high calcium limestone.  [c.177]

The lithium-bearing oil-field waters of southern Arkansas and eastern Texas contain high concentrations of calcium chloride. The appHcation of ion-exchange technology has been proposed where lithium is selectively absorbed from brines high ia calcium and sodium, and then recovered through regeneration usiag an aqueous solution of low lithium concentration. Ion adsorption resias for this appHcation are prepared by forming crystalline LiOH 2A1(0H)2 by reaction of Al(OH)2 suspended ia the resia with aqueous LiOH at elevated temperatures. The crystalline LiOH 2Al(OH)2 thus  [c.223]

The main growing areas for badey are North Dakota, Montana, eastern South Dakota, and western Minnesota six-row badey is predominant. Increasingly significant areas are California, Oregon, Washington, Idaho, and Colorado, where predominandy two-row badey is produced. Less than one-half of the badey grown in the United States is processed by the malt industry the remainder is used as animal feed, and ca 80% of the badey used by the malting industry is the six-tow variety (2—5) (see Feeds and feed additives, pet foods).  [c.477]

Development. Several investigations have been made on the chemical changes taking place during the development of various nuts for instance, in macadamia (63) (see Table 7), pecan (65), almond (66), Knglish walnut (67), eastern black walnut (see Table 8), and tung (69). The levels of sugars and other carbohydrates decrease rapidly during oil synthesis, so that by the time the kernel is mature, most of the carbohydrates have disappeared. Since the decrease in carbohydrate levels in the kernel accounts for only a small proportion of the oil synthesized, it follows that the materials formed into oil come from other parts of the tree. For example, studies of the tung fmit at different stages of development show that even though all the carbohydrates are utilized for synthesis of oil in the kernel, a large part of the substances necessary for oil formation are brought in from outside the nut (69). The fat content in the eastern black walnut kernel increases out of proportion to any decrease in other constituents (68).  [c.275]

Thyme Oil. The water- and steam-distilled essential oil obtained from the partially dried herb of the wild-growiag Thymus vulgaris L., T. gis L., or related species is called thyme oil [8007-46-3], Various species of thyme grow abundantly ia the Mediterranean region as well as central and eastern Europe. In addition, the plant is cultivated ia many parts of the world as a dried cuUnary herb. Spain is a primary center for distillation. Thyme oil is a brownish orange-red Hquid with a rich, powerful, sweet, warm-herbaceous odor, very aromatic and spicy. The flavor is rich, warm, biting, spicy-herbaceous. In perfumery, the oil finds primary use ia functional products such as soap fragrances and only trace use ia fine perfumery. The principal use of thyme oil is ia flavors for sauces, dressiags, pickles, caimed meats, etc, and ia pharmaceutical preparations including mouth washes, gargles, dentifrices (qv), cough symps, and lozenges because of its excellent germicidal properties. A comparative analysis of the headspace volatiles over living and picked T. vulgaris and a commercial oil was performed and differences are shown ia Table 58 (101).  [c.339]

Because of its similar characteristics, the evaluation of the images filtered with the DroG filter is guided by the feature extraction of the morphological filter. The Gaussian smoothing property of the filter results in an output profile which has even less extrema then the results of the morphologic filter. This eases feature extraction, which starts with detection of the local extrema in the signal. Afterwards the characteristic step in the profile is detected and its shape is analysed analogously to the evaluation of the filter before-mentioned.  [c.462]

Ched Synthetics (S. Korea) Freudenberg Far Eastern (Taiwan) Hani1 (S. Korea)  [c.161]

Powell C J, Jablonski A, Tilinin I S, Tanuma S and Penn D R 1999 Surface sensitivity of Auger-electron spectroscopy and x-ray photoelectron spectroscopy J. Eiectron Spec. Reiat. Phenom. 98-9 1  [c.318]

The best way to perfonu IR spectroscopy studies on small samples is in the reflection-absorption (RAIRS) or adenuated total-reflectance (ATR) modes, which work best for opaque and transparent substrates, respectively. RAIRS has m fact become the method of choice for the study of adsorbates on well characterized metal samples, including single crystals. The first adempt to obtain spectra from adlayers on bulk metal samples was that of Pickering and Eckstrom, who in 1959 looked at die adsorption of carbon monoxide and hydrogen on metal films by using a multiple reflection teclmique with an incoming beam at close to nonual incidence to the surface [18]. It soon became clear that beder spectra could be obtained by usmg glancing incidence angles instead [19], and that the gain from using multiple reflection was not worth the complications connected with the required experimental set-up (the optimum number of reflections usually varies between 3 and 10, and results in signal intensity increases of only about 30-50% compared to those from single reflection) [20]. The theory for IR radiation reflection at metal surfaces was later developed by Greenler, who proved diat only the p-polarized component of the incident beam is capable of strong interaction widi adsorbates on metals, and that interference between that component of the incident and reflected rays sets an intense standing field at the surface which can yield an intensity enhancement of a factor of up to 25 compared to that from the perpendicularly polarized photons [21]. Many surface scientists have since taken advantage of these properties to perfonu reflection-absorption measurements of monolayers on solid metals [22, 23 and 24]. Even though the initial RAIRS experiments were carried out with molecules with large dynamic moments such as CO (in order to take advantage of their large absorption cross sections), recent ETIR developments have led to the possibility of detecting submonolayer quantities of species like hydrocarbons with much weaker signals on single crystals of less than 1 cm area [25].  [c.1781]

In the spring of 1964 1 transferred from Sarnia to Dow s Eastern Research Laboratories in Framingham, Massachusetts, outside Boston, established under the directorship of a friend, Fred McLafferty, and located initially in a converted old industrial building. When Christopher Ingold came to visit us there one day later in the year, he had difficulty in convincing the cab driver who drove him from his hotel in Boston to find the noted research laboratory in the dilapidated neighborhood the address indicated. The laboratory, however, soon moved to neighboring Wayland, into nice a campuslike setting. Fred built up an impressive laboratory in a short time, where it was possible to work under the most pleasant conditions. Harvard and MIT were just a half hour driving distance away and provided valuable contact with the academic community. Bill Lipscomb (Nobel Prize in chemistry.  [c.82]

The F H- H — H —> F—H + H reaction is a common example of a reaction easily studied by classical trajectory analysis. The potential surface we are interested in is that for FH2. This potential surface may have many extrema. One of them corresponds to an isolated Fluorine atom and a stable H2 molecule these are the reactants. Another extremum of the surface corresponds to an isolated hydrogen atom and the stable H-Fmolecule these are the products. Depending on how the potential surface was obtained there may or may not be an extremum corresponding to stable H2F, but at the least you would expect an extremum corresponding to the transition state of the reaction being considered.  [c.328]

By 1991 Western Europe was still the largest producer of acryUc fibers, with Bayer of Germany and Enichem of Italy the world s largest acryUc fiber companies. Worldwide, 24% of acryUc production was used for home fiirnishings and carpet, 75% for apparel, and 1% for industrial. A somewhat higher percentage, 6%, was used for industrial and automotive appHcations in Western Europe. The regional breakdown of world production should shift in the 1990s, with East Asian production increasing to levels comparable to Western Europe. Production in the People s RepubHc of China should rise dramatically, making that country self-sufficient in acryUc fiber. Exports from Western Europe and Japan will be hurt the most from this shift in world production. In general, production is forecast to decline in the most developed countries and in regions that depend heavily on acryUc exports. Production appears to be shifting to the next generation of low cost producers, namely South and East Asia, the Middle East, Africa, and Eastern Europe. Countries such as Taiwan and South Korea are losing their competitive advantage to rising wages and prices (107,108).  [c.286]

The source of hemp fiber is the plant Cannabis sativa (mulberry family, Moraceae) originating in central China. It is grown in central Asia and eastern Europe. The stem is used for fiber, the seeds for oil, and leaves and flowers for dmgs, among them marijuana. The stalks grow 5—7 m tall and 6—16 mm thick. The hoUow stems, smooth until the rough foflage at the top, are hand cut and spread on the ground for dew retting for the highest quaUty product. Water retting is used on sun-dried bundles from which the seeds and leaves have been removed. Strands of hemp fiber can be 2 m in length. The fibers are graded for color, luster, spinning quaUty, density, cleanliness, and strength.  [c.361]

In a variation on the usual methods for producing syntactic foams (120,121), expandable polystyrene or styrene—acrylonitrile copolymer particles (in either the unexpanded or prefoamed state) are mixed with a resin (or a resin containing a blowing agent) which has a large exotherm during curing. The mixture is then placed in a mold and the exotherm from the resin cure causes the expandable particles to foam and squeeze the resin or foamed matrix to the surface of the mol ding. A typical example is Voraspan, expandable polystyrene in a flexible polyurethane foam matrix (122). These foams are finding acceptance in cushioning applications for bedding and furniture.  [c.408]

It can be concluded from other studies that deciduous trees are preferred over conifers for the production of biofuels (77). Several species can be started readily from clones, resprout copiously and vigorously from their stumps at least five or six times without loss of vigor, and exhibit rapid initial growth. They also can be grown on sites with slopes as steep as 25%, where precipitation is 50 cm or more per year. It has been estimated that yields between about 18 and 22 dry t/hm yr are possible on a sustained basis almost anywhere in the Eastern and Central time 2ones in the United States from deciduous trees grown in dense plantings. A representative Hst of deciduous trees judged to have desirable growth characteristics for methane plantations, and shown to grow satisfactorily at high planting densities on short and repeated harvest cycles, is available (77).  [c.34]

MetaUic glasses are metastable. A combination of thermal energy and time leads to crystallisation. At room temperature, this may require a very long time but at moderate temperatures of 373 K or more (depending on the alloy) devitrification can occur in minutes. Usually the crystallisation temperature is given as the temperature at which crystallisation begins as the alloy is heated at a constant rate. Figure 7 is a differential scanning calorimeter (dsc) trace for an Alg Ni Fe2Gdg glass. 7, the crystallisation temperature, is defined as the onset temperature or the peak temperature of the first exotherm in the dsc scan. In this case crystallisation begins at 543 K. Crystallisation leads to an increase in density of about 1%. In general, T is somewhere between 0.4 and 0.65 where is the melting temperature, which for specific alloys is 400 K for Mg-based glasses and 1200 K for refractory amorphous material. The commercially important ferromagnetic iron-based glasses have T values of about 700 K (69).  [c.338]

Another iategrated project is the VEB Gaskombiaat Schwarze Pumpe plant ia eastern Germany. This complex consists of three briquetting plants, three power stations, one brown coal high temperature coking plant, and one pressure gasification plant. Open-cast mines near Welzaw-Sud and Nochten produce soft brown coal. The overburden ratio is about 5.2 1. The equipment can remove up to 60 m of overburden and has a capacity of 20, 000 m /h (1.7 X 10 ft /d). The raw brown coal goes to both the briquetting plants and power stations. Some briquettes are produced directly for fuel, others go to the coke-oven plant to produce coke and Hquid products or to the pressure gasification plant to produce gas and Hquid products. The power station generates both electric energy and steam which is used on-site. The fuel gases from the coke-oven plant and the oil and coal gasification plants are blended, after purification, with product gases from the natural gas reformer to provide town gas. The capacity is estimated at 13 x 10 m /d (450 x 10 ft /d) town gas which has a heat content of 15.9 M J/m (ca 430 Btu/ft ). The composition of the town gas is 1.3% CO2, 12.3% CO, 0.84% O2, 22.9% CH, 34.4% H2, 26.2% N2, 0.94% 0.53% C Hg, 0.56% C H q, and 0.03% C2H. This gas is obtained by blending natural gas from eastern Germany and  [c.159]

Calcium Silicate Products. Quicklime is used as the cementitious binder in making autoclaved building materials based on calcium sdicate, ie, sand—lime brick, cellular (or foam) concrete block and insulation material, and the former USSR extremely dense and reinforced siUcate-concrete building materials. Lime reacts with fine siUca in the autoclave under steam and pressure to form strong dicalcium siUcate cement compounds, representing a type of cementless concrete because no Portland cement is used in the mix. Use of these building materials is growing steadily in Germany, Scandinavia, the Netherlands, the eastern European countries, AustraUa, Canada, and Japan, but tittle use is made of them in the United States. They are economically useful, can be mass produced, and are of stable quality. By increasing the foaming agent in cellular concrete, an extremely lightweight insulation, microporite, can be produced. Only time (no limestone) is used in these products.  [c.177]

The ha2ard of exposure of personnel to microwave energy has been thoroughly reviewed (112,113). Exposure safety limits in Western countries are reasonably similar (Fig. 5), at least in the microwave frequency range. The most advanced standard includes detailed rules dependent on frequency, degree of partial body exposure, exposure time, contact conditions, etc (114). In the microwave range the recommended limits are in the range of 0.3 to 10 mW/cm as averaged over any 6 or 30 minute period depending both on frequency and whether the environment is controlled or uncontrolled. Limits in eastern Europe for many years were much more stringent at microwave frequencies (115).  [c.344]


See pages that mention the term Extreme Thinness : [c.551]    [c.2527]    [c.3058]    [c.124]    [c.125]    [c.303]    [c.328]    [c.61]    [c.141]    [c.68]    [c.925]    [c.303]    [c.368]    [c.377]    [c.45]    [c.267]    [c.305]    [c.436]    [c.328]   
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The coming of materials science  -> Extreme Thinness