Hydrogenation, thermal

The discussions of the structure and the electron density are based on the structure found by a full multipole refinement of the X-ray data with the hydrogen positions fixed at the neutron values and the hydrogen thermal parameters fixed at scaled neutron values (Figure 5).1 The interatomic distances and intramolecular bond angles are given in Table 2. 

Gasification coupled with water-gas shift is the most widely practiced process route for biomass to hydrogen. Thermal, steam, and partial oxidation gasification technologies are under development. Feedstocks include both dedicated crops and agricultural and forest product residues of hardwood, softwood, and herbaceous species. 

HT - Hydrogen Thermal NT - Nitrogen Thermal HCD - Hydrogen Catalytic Dry... 

Well defined oxide phases can be obtained by thermal dissociation of oxalates, by controlled oxidation of compounds or actinide saturated ion exchangers or by reduction of higher oxides with hydrogen. Thermal dissociation of compounds often results in oxides of low density high (almost theoretical) density oxides can be prepared in sol-gel processes. 

K-absorption spectrum of yttrium in YH3, which was mechanically treated in a ball planetary mill during 20 min. with angular rate of 1630 rot./min. is shown in Fig. 6 (c). This absorption spectrum, as seen from the picture, is shifted relatively to the spectrum of untreated YH3 hydride to the side of lower energies, which in accordance with the found out correlation has to testify to thermal stability of reduction of treated yttrium hydride. Actually, we determined by the method of hydrogen thermal desorption, that as a result of mechanic dispersing of this hydride its temperature of decomposition decreased more than on 300 °C (Fig. 7), i.e. the... 

Zaika Yu.V., Chernov I.A. (2003) Nonlinear dynamical boundary-value problem of hydrogen thermal desorption, Int. J. of Mathematics and Math. Sciences 23, 1447-1463. 

Neptime s atmosphere was found to be similar to that of Uranus in that it seems to have little temperature change with latitude. This probably indicates enormous heat capacities for both atmospheres. Also Neptune has a hot (about 900 F [482 C]) ionosphere and an exosphere that consists mainly of a hydrogen thermal corona both these atmospheric components seem similar to those of Uranus. However, Neptune s stronger gravity and slightly colder stratosphere cause much lower particle densities in Neptune s upper atmosphere than are found at the same heights above the cloud layers in Uranus s atmosphere. 

It has been well known for a couple of decades that noncrystalline metallic alloys can be made by vapour- and melt-quenching. Recent results show that an amorphous phase can also be formed directly when a crystalline metallic alloy is subjected to various types of disordering processes. Solid-state amorphization can be induced through a variety of methods including absorption of atomic hydrogen, thermal interdiffusion reaction along the interface separating... 

Figure 25.11 Selected hydrogen thermal desorption traces obtained from a bimetallic Cu—Ru surface (Cu coverage = 0.7 monolayers on a Ru(0001) surface) as a function of adsorption temperature The top curve (a) was obtained after the system had received a saturation exposure at 100 K curve (b) Hj desorption trace after a saturation exposure at 230 K. The dashed line indicates the direct superposition of (a) onto (b). The bottom curve (c) represents the difference (b) — (a) and, hence, is equal to the amount of hydrogen spilled over from Ru to Cu sites at 230 K. After Goodman and Peden [88].

Figure 7.40. Carbon-14-labeled ethylene (or other alkenes) was chemisorbed as a function of temperature on the flat Pt(l 11) crystal face. The (H/C) ratio of the adsorbed species was determined from hydrogen thermal desorption. The amount of preadsorbed alkene that could not be removed by subsequent treatment in 1 atm of hydrogen represents the irreversibly adsorbed fraction. The adsorption reversibility decreases markedly with increasing adsorption temperature as the surface species become more hydrogen-deficient. The irreversibly adsorbed species have long residence times, on the order of days [195].

Thermal black is made from natural gas by the thermatomic process in which methane is cracked over hot bricks at a temperature of 1,600°F (871°C) to form amorphous carbon and hydrogen. Thermal black consists of relatively coarse particles and is used principally as a pigment. A few grades (FT and MT referring to fine thermal and medium thermal) are also used in the rubber industry. 

Oxygen specific heat at constant volume Nitrogen specific heat at constant volume Hydrogen specific heat at constant volume Water specific heat at constant volume Oxygen thermal conductivity Nitrogen conductivity Hydrogen thermal conductivity Water thermal conductivity... 

Fig. 31. Hydrogen thermal desorption spectra illustrating the sequential dehydrogenation of ethylene, propylene, and cis-2-butene chemisorbed on the Pt(lll) crystal surface at 120 K. The rate of heating is 12 K/sec...

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