Hydrogen density

Fig. 5(a) contains the oxygen and hydrogen density profiles it demonstrates clearly the major differences between the water structure next to a metal surface and near a free or nonpolar surface (compare to Fig. 3). Due to the significant adsorption energy of water on transition metal surfaces (typically of the order of 20-50kJmoP see, e.g., [136]), strong density oscillations are observed next to the metal. Between three and four water layers have also been identified in most simulations near uncharged metal surfaces, depending on the model and on statistical accuracy. Beyond about...

Zuttel, A., P. Wenger, P. Sudan, P. Maurona, S.-i. Orimob, Hydrogen density in nanostructured carbon, metals and complex materials. Mater. Sci. Eng. B108, 9-18, 2004. 

Assuming a cosmic-ray confinement time of 106 7 years and an interstellar hydrogen density of 1 atom cm-3, with present-day CNO abundances, use Eq. (9.10) to deduce Q/W for beryllium. 

Figure 11.3. Volumetric and gravimetric hydrogen density of selected hydrides (Zuttel, 2003).

M molecular mass, p gravimetric density, melting point, decomposition temperature, X gravimetric hydrogen density... 

Ziittel, A., Wenger, R, Sudan, R, Maurona, R, Orimo, S. 2004. Hydrogen density in nanostruc-tured carbon, metals and complex materials. Mater Sci Eng B 108 9-18. 

Figure 5.4 Schematic of the geometrical configuration for hydrogen-air flame and sofid fuel. The geometry corresponds to the experimental setup. The initial shape of the HED fuel was a circular arc segment as shown above. The relevant material properties air density = 1.91 kg/m , hydrogen density = 0.0898 kg/m . For the turbulent quantities at the inlet k = (O.OSf/miet) = 9.59 (m/s), = C fc / /(0.03Liniet) = 6360 m /s , jjkt = Cfe = 0.00248 kg/ms. For the fuel sample, m.p. is 450 K, latent heat of fusion is 72.7 J/g. Dimensions in mm. Air inlet velocity 103.3 m/s, hydrogen injection velocity 800 m/s...

The volumetric hydrogen density describes the mass of hydrogen in a material or a system divided by the volume of the material or storage system ... 

The volumetric density of hydrogen in a pressure vessel increases with pressure and reaches a maximum above 1000 bar, depending on the tensile strength of the material. However, the gravimetric hydrogen density of the pressure cylinder... 

The gravimetric and volumetric hydrogen density depend strongly on the size of the storage vessel since the surface-to-volume ratio decreases with increasing size. Therefore, only the upper limit is defined (Figure 5.11). 

Figure 5.11 Hydrogen density for compressed hydrogen, liquid and solid hydrogen.

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