Dysprosium pressure

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,... 

Lanthanide bromides and iodides have found important applications in a completely different field. They are added as additives in high-pressure discharge lamps in the lighting industry to improve the arc stability and the colour quality. The latter is due to the contribution of the multiline spectrum of the doped rare earths which are added to the salt mixture. Lanthanide trihalides of dysprosium, holmium, thullium, gadolinium and lutetium are used frequently for this purpose (Hilpert and Niemann, 1997). 

Test samples were fabricated by Si and Ge monohydrides pyrolysis in the gas mixture at the total pressure of 35-40 Pa with monogerman to monosilane volume ratio of 0.001-0.002. Temperature of the process was not higher than 680°C. P-doped silicon wafers (100) were used as substrates. Before the pyrolysis process we have oxidized the surface of some silicon wafers in dry oxygen in order to form thin silicon dioxide layer. In addition dysprosium and yttrium oxides were also formed on the wafer surface for other samples by the process of their deposition and following oxidation. 

The commercially important samarium-containing minerals are treated with concentrated sulfuric acid or, in the case of monazite, with a solution of sodium hydroxide (73%) at approximately 40°C (104°E) and under pressure. The element is separated from the solutions via solvent extraction or ion exchange. Sm salts are weakly yellow and may exhibit ion emission. Sm ions show luminescence and are sometimes used to generate lasers. Samarium is used in the manufacture of headphones and tape drivers, see ALSO Cerium Dysprosium Erbium Europium Gadolinium Holmium Lanthanum Lutetium Neodymium Praseodymium Promethium Terbium Ytterbium. 

Measured local field, calculated dipolar field and derived contact field together with their pressure coefficients at various temperatures for dysprosium and holmium metals (Schreier et al. 2000b)... 

Recently, Yamamoto s group reported that in-plant waste (sludge) was separated into liquid iron and solid rare-earth oxide phases at 1550 °C under argon atmosphere having partial O2 pressure of 10 ° -10 atm without any flux additions (Kubo et al., 2009). They also showed that almost all of the neodymium and dysprosium existed in the oxide phase and iron content in the oxide phase was less than 0.4 mass% (Katayama et al., 2010). 

Dysprosium (Dy) has electronic configuration of [Xe] 6s 5d 4f . The complete trivalent lanthanide crystal stmcture sequence can also be accessed in Dy with the application of pressure. Dysprosium has been extensively studied to various pressure ranges (Patterson et al., 2004 Samudrala and Vohra, 2012 Shen et al., 2007). 

FIGURE 30 The ADXD spectra of dysprosium at various pressures showing all five phases seen in it when compressed to 210 GPa (Samudrala and Vohra, 2012). 

From the studies conducted on dysprosium, the average bulk modulus is calculated to be 36 2 GPa and the pressure derivative of bulk modulus is given as 3.5 0.5. The third order Birch-Mumaghan fit is given by Eq. (1), where X=(Vo/V). 

FIGURE 31 Volume per atom as a function of pressure for dysprosium the Birch-Mumaghan equation of state fits from Samudrala and Vohra (2012). 

The most common raw materials for the REM molten salt electrolysis are in the RE " state, such as RE2O3, RECI3. But RE " still exists to a certain extent in the molten salts, especially in the chloride melts, some rare earth metal elements have presented a higher level of divalent oxidation states, such as neodymium, samarium, europium, dysprosium, thulium, and ytterbium, which result in a lower current efficiency. For Sm and Eu molten salt electrolysis processes, even no metals can be obtained at the cathodes due to a cyclic transformation of Sm VSm (Eu /Eu ) and Sm /Sm (Eu /Eu ) on the electrodes during electrolysis. And some of the rare earth metal elements show tetravalent oxidation states at the chlorine pressure far in excess of atmospheric pressure, such as Ce. Most of the rare earth metal elements in oxidation state of -1-4 are not stable in chloride melts, because the reaction occurs according to the following equation RE " -I- Cl = RE -" -I- I/2CI2. 

In this work, semilogarithmic plots over the temperature range 770-1009 K are given for DyQs calculations by the second law were not performed because this interval covers saturated vapor pressures for both the sublimation of the a polymorph and vaporization of liquid dysprosium trichloride. 

The reliability of measurements of the partial pressures of R2CI6 can in principle be verified by a standard procedure based on changes in the thermod)mamic characteristics of these molecules along the lanthanide series. However, the enthalpy of atomization AatH°(298) is not the most convenient parameter for such a check since it does not vary monotoni-cally with the number of the lanthanides in the series. The plot of this dependence is a broken line with maxima at lanthanum, gadolinium, and lutetium compounds and minima at europium and ytterbium compounds. In addition, the enthalpy of atomization usually increases in going from dysprosium to erbium dimers. 

The shape of the curve shown in Figure 56 predicts a fairly high stability of neodymium and promethium dichlorides among the compounds with CN = 9 and dysprosium and thulium dichlorides among the compounds with CN = 7, that is, exactly those lanthanide dichlorides that (except PmCl2) not only were successfully synthesized but also were the subject of some physicochemical measurements that required heating to high temperatures. For instance, saturated vapor pressure of... 

Evseeva, G.V., Zenkevich, L.V., 1976. Vestn. Mosk. Univ. Khim. 17,110 (in Russian). Evseeva, G.V., Zenkevich, L.V., 1978. Vestn. Mosk. Univ. Khim. 19,89 (in Russian). Evseeva, G.V., Zenkevich, L.V., 1979. Determination of Vapor Pressure of Dysprosium Chloride. Available from VINITI. No. 2265-79 (Moscow, 1979) (in Russian). 

The goal of this study was to investigate single step conversion of methane to higher hydrocarbons over dysprosium oxide at different temperatures and at different partial pressures of oxygen. 

Preparative Method dysprosium triflate is commercially available. However, it can be prepared by adding an excess of commercially available Dy(III) oxide to an aqueous solution of tri-fluoromethanesulfonic acid (50% v/v) and heating at reflux for 30 min to 1 h before filtration to remove unreacted oxide. The water can then be removed under reduced pressure, and the hydrate can he dried by heating under vacuum at 180-200 °C for 48 h. 

Squire found that improved conversions of aromatic compounds and higher yields of aromatic amine were obtained when the aromatic compound reacted with ammonia in the presence of water at elevated temperamre and pressure using a conditioned Ni/NiO/Zr02 cataloreactant [67]. Delpesco also provided a strategy for improving the conversions of aromatic compounds to aromatic amines by prolonging the life of cataloreactant at a temperamre from about 150-500 °C at a pressure of from about 10-1000 atm. To this end, a dopant such as an oxide of lanthanum, samarium, holmium, europium, erbium, praseodymium, neodymium, terbium, ytterbium, dysprosium, yttrium, or mixtures thereof was added into Ni/NiO/Zr02 cataloreactant [68]. 

Basler, D.B., 1972, High Temperature Oxidation of Gadolinium and Dysprosium Under Controlled Oxygen Partial Pressure, Ph.D. Thesis, Iowa State University, Ames, Iowa. 

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