Amplitude of roughness

We can see intuitively that cell geometry has little to do with micro throwing power. If the amplitude of roughness is of the order of 0.1 pm or less and the distance between the anode and the cathode is a few centimeters, the variation of solution resistance at crests and valleys on the surface must be negligible. Hence primary current... 

The Nemst diffusion layer thickness is larger in a recessed area than at a crest, hence the local current density is smaller. As a result, recessed areas grow more slowly than crests, and the amplitude of roughness increases with time during plating. 

In the case of the mechanically polished surface, the amplitude of roughness was several atomic diameters of Cu (Fig. 2.29c, d), whereas the mechanically and electrochemically polished stuface exhibited smoothness on the atomic level (Fig. 2.29e, f). The increase in the specular reflection of 20-25 % is due to this fact. It is interesting to note (Fig. 2.29g) that the structure of the bright surface was not oriented. This is in accordance with the assumption that the dissolution process under polishing conditions is a random process. 

As shown in Fig.l, one surface possesses striated roughness with long narrow ridges and furrows. C is the direction along which the amplitude of roughness is varied smoothly and slowly. is perpendicular to 5. That... 

The significance of this term can be realized by the fact that the voltage stress of a surge, having a maximum amplitude of 4.5 p.u.. with a front time / of 5 ps. will roughly be the same or even less severe compared to a surge with an amplitude of only 2 p.u. and a front time of 0.2 ps (see Insulation Sub-committee. Rotating Machinery Committee, 1981). 

Fig. 5.15 Schematic representation of the normal modes of the Fe(ni)-azide complex with the largest iron composition factors. The individual displacements of the Fe nucleus are depicted by a blue arrow. All vibrations except for V4 are characterized by a significant involvement of bond stretching and bending coordinates (red arrows and archlines), hi such a case, the length of the arrows and archlines roughly indicate the relative amplitude of bond stretching and bending, respectively. Internal coordinates vibrating in antiphase are denoted by inward and outward arrows respectively (taken from [63])...

The flammability and stability limits of Fig. 19.7 were obtained using fuel-air mixtures with the same equivalence ratio in the radial and tangential inlets, and without an axial jet. The lean flammability limit decreased from 0.57 to 0.4 as the swirl number was increased from 0.6 to 3.75, and the region of high-heat release moved closer to the swirler which represented an acoustic pressure antinode for the naturally occurring oscillations associated with a quarter wave in the entire duct, with frequency close to 200 Hz. Thus, swirl led to an increase in the amplitude of oscillations and to an earlier transition from smooth to rough combustion with antinodal RMS pressures up to 10 kPa, and initiated at an equivalence ratio of 0.5 for a swirl number of 3.75... 

The tendency of premixed flames to detach from the flame holder to stabilize further downstream has also been reported close to the flammability limit in a two-dimensional sudden expansion flow [27]. The change in flame position in the present annular flow arrangement was a consequence of flow oscillations associated with rough combustion, and the flame can be particularly susceptible to detachment and possible extinction, especially at values of equivalence ratio close to the lean flammability limit. Measurements of extinction in opposed jet flames subject to pressure oscillations [28] show that a number of cycles of local flame extinction and relight were required before the flame finally blew off. The number of cycles over which the extinction process occurred depended on the frequency and amplitude of the oscillated input and the equivalence ratios in the opposed jets. Thus the onset of large amplitudes of oscillations in the lean combustor is not likely to lead to instantaneous blow-off, and the availability of a control mechanism to respond to the naturally occurring oscillations at their onset can slow down the progress towards total extinction and restore a stable flame. 

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