Uranium promoter

For a naphtha feedstock,. the catalyst is based on nickel deposited on calcium or magnesium silico-aluminate incorporating potasskun, or nkkel on an alumina support with uranium promoter. Nickel on calcium aluminate is generally used for post-combustion. 

Catalysts used for preparing amines from alcohols iaclude cobalt promoted with tirconium, lanthanum, cerium, or uranium (52) the metals and oxides of nickel, cobalt, and/or copper (53,54,56,60,61) metal oxides of antimony, tin, and manganese on alumina support (55) copper, nickel, and a metal belonging to the platinum group 8—10 (57) copper formate (58) nickel promoted with chromium and/or iron on alumina support (53,59) and cobalt, copper, and either iron, 2iac, or zirconium (62). 

Control layers, such as those used to minimize animal intrusion, promote drainage, and control and collect landfill gas, are often included for conventional cover systems and may also be incorporated into ET cover system designs. For example, a proposed monolithic ET cover at Sandia National Laboratories in New Mexico will have a biointrusion fence with 1/4-in. squares between the topsoil layer and the native soil layer to prevent animals from creating preferential pathways, potentially resulting in percolation. The biointrusion layer, however, will not inhibit root growth to allow for transpiration. At another site, Monticello Uranium Mill Tailings Site in Utah, a capillary barrier ET design has a 12-in. soil/rock admixture as an animal intrusion layer located 44 in. below the surface, directly above the capillary barrier layer. 

Heterojunction with intrinsic thin layer (HIT) photovoltaic cell, 23 46-47 Heteroleptic uranium complexes, 25 441 Heterologous promoters, 22 453 Heteronano interface (HNI), 23 838 Heteronium bromide, 4 359t Heteronuclear metal carbonyls, synthesis of, 26 69-71... 

Field measurements in sedimentary fluvial-type calcrete deposits also suggest that present-day groundwater in these areas may also display potential to both dissolve and precipitate uranium in the near surface. Chemical dilatancy and evaporation-driven diffusion that promote de-complexing, diffusion, and reprecipitation mechanisms are seen to play integral parts in the continued chemical reworking and modification of these calcrete-hosted carnotite deposits. 

The main emphasis was laid, in this initial work, on Haber s catalysts, e.g., osmium and uranium compounds, as well as on a series of iron catalysts. Some other metals and their compounds which we tested are, as we know today, less accessibble to an activation by added substances than iron. Therefore, they showed no improvement or only small positive effects if used in the form of multicomponent catalysts. Finally, the substances which we added to the metal catalysts in this early stage of our work were mostly of the same type as those which had proved to favor the nitride formation, e.g., the flux promoting chlorides, sulfates, and fluorides of the alkali and alkaline earth metals. Again, we know today that just these compounds do not promote, but rather impair the activity of ammonia catalysts. 

Metals other than iron which catalyze the ammonia synthesis such as osmium, ruthenium, uranium, and molybdenum can also be promoted by added substances. However, several of these metals do not show improvements of the same magnitude as does iron. Further-... 

Molybdenum In its pure form, without additions, it is the most efficient catalyst of all the easily obtainable and reducible substances, and it is less easily poisoned than iron. It catalyzes in another way than iron, insofar as it forms analytically easily detectable amounts of metal nitrides (about 9% nitrogen content) during its catalytic action, whereas iron does not form, under synthesis conditions, analytically detectable quantities of a nitride. In this respect, molybdenum resembles tungsten, manganese and uranium which all form nitrides during their operation, as ammonia catalysts. Molybdenum is clearly promoted by nickel, cobalt and iron, but not by oxides such as alumina. Alkali metals can act favorably on molybdenum, but oxides of the alkali metals are harmful. Efficiency, as pure molybdenum, 1.5%, promoted up to 4% ammonia. 

Uranium (studied at an early stage by Haber). It can be promoted by certain metals. 1.0% to 2.5% ammonia. 

Wielinga, B. Bostick, B. Hansel, C.M. Rosenz-weig, R.F. Fendorf S. (2000) Inhibition of bacterially promoted uranium reduction Ferric (hydrjoxides as competitive electron acceptors. Environ. Sd. Tedm. 34 2190-2195... 

Otto Hahn, 1879-. President of the Max Planck Society for the Promotion of Science. Discoverer with F. Strassmann, in 1938, of the splitting of uranium and of thorium by neutron irradiation into two elements of medium weight. Discoverer of radioactinium, radiothorium, mesotliorium, uranium Z, and (with Miss Lise Meitner) protactinium. He has devised radioactive methods for determining the geologic and biologic age of materials. In 1945 he received the Nobel Prize for Chemistry for the year 1944. 

The uneven distribution of elements across the face of the earth has shaped history - stimulating trade and encouraging exploration and cultural exchange, but also promoting exploitation, war, and imperialism. Southern Africa has paid dearly for its gold and the elemental carbon of its diamonds. Many rare but technologically important elements, such as tantalum and uranium, continue to be mined from poor regions of the world under conditions (and for reasons) that some consider pernicious and hazardous. 

Certain types of catalyst uranium oxide and chromium oxide may be used as a promoter. This is reported to give a higher resistance to catalyst poisoning by sulfur components and a lower tendency to form carbon deposits. 

Although the trivalent uranium species of the tetrapyrrolide polyanions display a very high reactivity, no evidence was found for the ability to interact with N2. However, the reduction of the trivalent [ [(—CH2 )5]4-calix[4]tetrapy-rrole U(dme)][K (dme)] with [K-(naphthalenide)] in DME afforded N2cleavage with formation of the mixed-valenceU(IV)-U(V) nitride below (Scheme 13) (36). The highly reactive species that performs the N2 cleavage in this case was not identified since reactions carried out under an Ar atmosphere promoted solvent deoxygenation, as well as depolymerization of polysilanol. 

This 1949 DuPont promotional photo shows how a Teflon rod (on our right, in the model s left hand) resists a hot acid solution compared with a rod made from another plastic. In World War II, Teflon was used for insulation in aircraft wiring and for seals in the equipment used to enrich corrosive uranium hexafluoride. 

Committee on Health Effects Associated with Exposures during the Gulf War, Division of Health Promotion and Disease Prevention, Institute of Medicine of the National Academies (2000). Gulf War and Health Vol. 1. Depleted Uranium, Pyridostigmine Bromide, Sarin, and Vaccines (C.E. Fulco,... 

The only system which seems to be promising for industrial application is ruthenium promoted with rubidium on graphite as carrier (see Section 3.6.2.3). Further information on structure, activity and reaction mechanism of non-iron catalysts is given in [102], [172]-[175], Specific references vanadium [176], uranium [177], molybdenum [178]-[180], tungsten [181]. 

In general, the catalysts contain varying quantities of the oxides of aluminum, potassium, calcium, magnesium, and silicon as promoters. Patents recommend adding sodium [243], beryllium [244], vanadium [245], uranium [246], or platinum [247]. Reference [248] describes cesium-containing catalysts. Catalysts patented by Lummus [249] and Ammonia Casale [250] contain cerium as additional promoter. ICI [251] has developed a cobalt-containing catalyst, as has Grande Paroisse [252]. 

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