Dysprosium


While dysprosium has not yet found many applications, its thermal neutron absorption cross-section and high melting point suggest metallurgical uses in nuclear control applications and for alloying with special stainless steels. A dysprosium oxide-nickel cermet has found use in cooling nuclear reactor rods. This cermet absorbs neutrons readily without swelling or contracting under prolonged neutron bombardment. In combination with vanadium and other rare earths, dysprosium has been used in making laser materials. Dysprosium-cadmium chalcogenides, as sources of infrared radiation, have been used for studying chemical reactions.  [c.191]

The cost of dysprosium metal has dropped in recent years since the development of ion-exchange and solvent extraction techniques, and the discovery of large ore bodies. The metal costs about 300/kg in purities of 99+%.  [c.192]

Dysprosium(III) ion Dy (aquo) hydrolysis  [c.845]

Above room temperature, the trivalent lanthanide ions are paramagnetic, with the exception of diamagnetic lanthanum and lutetium. Tetravalent cerium and divalent ytterbium are also diamagnetic. For the metals, when the temperature is lowered, the spin and orbital moments line up. The metals become antiferromagnetic or even ferromagnetic, eg, gadolinium, terbium, or dysprosium. The magnetism of the rare earths is highly anisotropic and is important in some industrial appUcations.  [c.540]

Most of the lower alkyl methacrylates readily polymerize in water in the presence of a surfactant and a water-soluble initiator. The final product is an opaque, gray, or milky-white disperson of high molecular weight polymer at a concentration of 30—60 wt % in water. The particle size of methacrylic—acrylic copolymer dispersions ranges from ca 0.1 to 1.0 p.m. These emulsion polymerizations are usually rapid and give high molecular weight polymers at high concentration and low viscosity. Difficulties in agitation, heat transfer, and material transfer, which are often encountered in the handling of viscous polymer solutions, are greatly decreased with aqueous dispersions. In addition, the safety hazards and the expense of flammable solvents are  [c.266]

A receptor model (78) and a source-oriented deterministic model were combined as part of a particulate air quahty control strategy analysis in Portiand, Oregon. Using CMB techniques, source contributions to the ambient aerosol were identified and then dispersion modeling was used to confirm the source contributions. The results obtained with the two models were compared, and a revised particulate emissions inventory was input into the source-dispersion model. Finally, the revised emissions inventory was used in dispersion modeling of emission control strategy alternatives. This approach utilized the strengths of both types of models. Receptor models are suitable for predicting the outcome of perturbations in some sources but not others. They are, however, good for determining the sources of particulate matter when an accurate emissions inventory is not available. Disperson models, on the other hand, are weU-suited for modeling the impact of a wide variety of emissions changes that would result from changed emission control regulations, but rely totally on an input emissions inventory, which may be uncertain or difficult to obtain.  [c.385]

Gr. dysprositos, hard to get at) Dysprosium was discovered in 1886 by Lecoq de Boisbaudran, but not isolated. Neither the oxide nor the metal was available in relatively pure form until the development of ion-exchange separation and metallographic reduction techniques by Spedding and associates about 1950. Dysprosium occurs along with other so-called rare-earth or lanthanide elements in a variety of minerals such as xenotime, fergusonite, gadolinite, euxenite, poly erase, and blomstrandine. The most important sources, however, are from monaziate and bastnasite. Dysprosium can be prepared by reduction of the trifluoride with calcium.  [c.191]

Materials that have shown a response to a magnetic stimuli have primarily been inorganic in chemical composition, alloys of iron, nickel, and cobalt doped with rare earths. TERFENOL-D, an ahoy of terbium, dysprosium, and iron, Tb Dy Fe with x between 0.27 and 0.30 andj between 1.90 and 1.95, is probably the most effective magnetostrictive material. The name TERFENOL is an acronym for two of the elements present in the ahoy and NOL refers to the Naval Ordinance Laboratory where this type of material behavior was developed. Magnetostriction occurs at its fullest potential in crystalline materials. Cost still appears to be one of the hindrances of magnetostrictives in reaching commercial importance. However, over the past three decades there has been a great interest in the development of organic and organometahic magnets. Several key features of these new magnets due to their organic nature include that these types of magnets do not have extended three-dimensional stmctural networks and they can be made using common solvents at low temperatures with a multitude of different synthetic techniques.  [c.250]

Parameter Gadolinium Terbium Dysprosium Holmium Erbium ThuUmn Ytterbium Lutetium  [c.541]

Metamagnetism refers to the appearance of a net magnetization resulting from a transition from antiferromagnetism to ferromagnetism by the appHcation of a strong field or by a change of temperature. Manganese diauride [12006-65-4], Mn Au and iron(II) chloride [7758-94-3], FeCl2, undergo the transition by field appHcation, and heavy rare-earth metals, eg, terbium [7440-27-9], dysprosium [7429-91-6], and holmium [7440-60-0], undergo the transition by temperature change.  [c.366]

Some nut trees accumulate mineral elements. Hickory nut is notable as an accumulator of aluminum compounds (30) the ash of its leaves contains up to 37.5% of AI2O2, compared with only 0.032% of aluminum oxide in the ash of the Fnglish walnut s autumn leaves. As an accumulator of rare-earth elements, hickory greatly exceeds all other plants their leaves show up to 2296 ppm of rare earths (scandium, yttrium, lanthanum, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium). The amounts of rare-earth elements found in parts of the hickory nut are kernels, at 5 ppm shells, at 7 ppm and shucks, at 17 ppm. The kernel of the Bra2d nut contains large amounts of barium in an insoluble form when the nut is eaten, barium dissolves in the hydrochloric acid of the stomach.  [c.272]

Butvar Disperson BR Besin Technical Bulletin, Pubhcation No. 6019-D, Monsanto Chemical Co., St. Louis, Mo., 1989.  [c.457]

The HFBR core uses fully-enriched (93%) uranium oxide-aluminum cermet curved plates dad m aluminum. The core height is 0.58 m and the diameter is 0.48 m or a volume of 103.7 Itr. The U-235 weighs 9.83 kg supported by a grid plate on the vessel bottom. The coolant flow u downward. Iience. How reversal is necessary for natural circulation. It operating temperature and pressure are 60 ( and 195 psi. There are 8 main and 8 auxiliary control rod blades made of europium oxide (Lii A)o and dysprosium oxide (DyjO,), clad in stainless steel that operate in the reflector region. The scram system is the winch-clutch release type to drop the blades into the reflector region. Actuation of scram causes a setback for the auxiliary control rods which are driven upward by drive motors,  [c.411]

Trihydroxy-21-diazopregnan-20-one 3,19-diacetate, 176 3 a,20,23 -Trihydroxy-16a-methyl-17(20)-oxido-11-0X0-2l-norchol-22-enoic acid 24(20)-lactone 3,23,diacetate, 191 3a,l l, 20 -Trihydroxy-5/3-C-norpregnane-l l -carboxylic acid, 438 3/3,11 a ,20/3-Trihydroxy-5o -pregnan-18-oic acid 18,20-lactone-3,l 1-diacetate, 252 3/3,5/S, 19-Trihydroxypregnan-20-one 3,19-diacetate, 176  [c.464]


See pages that mention the term Dysprosium : [c.45]    [c.147]    [c.147]    [c.147]    [c.147]    [c.235]    [c.191]    [c.191]    [c.192]    [c.194]    [c.216]    [c.240]    [c.277]    [c.306]    [c.319]    [c.348]    [c.357]    [c.622]    [c.659]    [c.719]    [c.837]    [c.912]    [c.954]    [c.1184]    [c.350]    [c.350]    [c.350]    [c.350]    [c.217]    [c.539]    [c.542]    [c.190]    [c.51]    [c.186]    [c.441]    [c.425]   
Chemistry of the elements (1998) -- [ c.1229 ]