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Titanium associated with

The so-called titanium method used by Arrhenius et a/. (1951) assumes a so-called lutite veil depositing at a constant rate throughout the deep oceans. Titanium associated with this lutite fraction then is also assumed to accumulate at a constant rate. Variations in the accumulation rates of biogenic components can then be assessed. The initial titanium method was calibrated by a single radiocarbon date as discussed above. The method has not been used since it was discovered that accumulation rates of all detrital and biogenic components of deep-sea sediments are subject to change as a function of climatic history and focusing processes. [Pg.3181]

Hafnium [7440-58-6] Hf, is in Group 4 (IVB) of the Periodic Table as are the lighter elements zirconium and titanium. Hafnium is a heavy gray-white metallic element never found free in nature. It is always found associated with the more plentiful zirconium. The two elements are almost identical in chemical behavior. This close similarity in chemical properties is related to the configuration of the valence electrons, and for zirconium and... [Pg.439]

Peripheral pitting and etching associated with the low current densities arising outside the main machining zone occur when higher current densities of 45-75 A/cm are appHed. This is a recurrent difficulty when high alloy, particularly those containing about 6% molybdenum, titanium alloys are electrochemicaHy machined. [Pg.309]

Titanium Sesc uioxide. Ti202 has the comndum stmcture. At room temperature it behaves as a semiconductor having a small (0.2 eV) band gap. At higher temperatures, however, it becomes metallic. This is associated with marked change in the mean Ti—Ti distance. As with TiO, titanium sesquioxide, Ti202, may be made by heating a stoichiometric mixture of titanium metal and titanium dioxide powders at 1600°C under vacuum in an aluminum or molybdenum capsule. [Pg.119]

The electrolytic cells shown ia Figures 2—7 represent both monopolar and bipolar types. The Chemetics chlorate cell (Fig. 2) contains bipolar anode/cathode assembhes. The cathodes are Stahrmet, a registered trademark of Chemetics International Co., and the anodes are titanium [7440-32-6] Ti, coated either with mthenium dioxide [12036-10-17, RUO2, or platinum [7440-06-4] Pt—indium [7439-88-5] Ir (see Metal anodes). Anodes and cathodes are joined to carrier plates of explosion-bonded titanium and Stahrmet, respectively. Several individual cells electrically connected in series are associated with one reaction vessel. [Pg.73]

Selective catalytic reduction (SCR) is cmrently the most developed and widely applied FGT technology. In the SCR process, ammonia is used as a reducing agent to convert NO, to nitrogen in the presence of a catalyst in a converter upstream of the air heater. The catalyst is usually a mixture of titanium dioxide, vanadium pentoxide, and hmgsten trioxide. SCR can remove 60-90% of NO, from flue gases. Unfortunately, the process is very expensive (US 40- 80/kilowatt), and the associated ammonia injection results in an ammonia slip stream in the exhaust. In addition, there are safety and environmental concerns associated with anhydrous ammonia storage. [Pg.28]

In the perfect lattice the dominant feature of the electron distribution is the formation of the covalent, directional bond between Ti atoms produced by the electrons associated with d-orbitals. The concentration of charge between adjacent A1 atoms corresponds to p and py electrons, but these electrons are spatially more dispersed than the d-electrons between titanium atoms. Significantly, there is no indication of a localized charge build-up between adjacent Ti and A1 atoms (Fu and Yoo 1990 Woodward, et al. 1991 Song, et al. 1994). The charge densities in (110) planes are shown in Fig. 7a and b for the structures relaxed using the Finnis-Sinclair type potentials and the full-potential LMTO method, respectively. [Pg.366]

Iron is associated with silica sand, usually as a light surface stain on the grains. Amber glass develops ionic color centers or complexes of Fe-S-C added to the batch as iron sulfide and powdered anthracite. Although the Fe content be four or five times that shown in the example in Table I, it appears to be bound in the complex so that no greater extraction occurs with the S and C. Titanium is associated with sand as... [Pg.25]

The most commonly used traditional Lewis acids are halides of aluminum, boron, titanium, zinc, tin, and copper. However, there are also more complex Lewis-acids that are quite effective catalysts that can be easily modified for carring out enantioselective processes, by incorporating chiral ligands. These can overcome some limitations associated with the use of classical Lewis acids [47]. [Pg.114]

The variation in the lattice vibration of the solid products was examined by utilizing the FT-IR technique at successive DGC process times and the results are presented in Fig. 5. The absorption bands at 550 cm and 450 cm" are assigned to the vibration of the MFI-type zeolite and the internal vibration of tetrahedral inorganic atoms. The band 960 cm" has been assigned to the 0-Si stretching vibration associated with the incorporation of titanium species into silica lattice [4], This indicates that the amorphous wall of Ti-MCM-41 was transformed into the TS-1 structure. [Pg.791]


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