Surface Streamer

Similar considerations might apply to bulking bmsh (2-6.3) and surface streamer (2-6.6) discharges which propagate across charged surfaces over distances up to about 1 m at source voltages less than 100 kV. 

Dielectric barrier discharges (DBD) is the case in which a dielectric material is placed on the electrode surfaces. Similar to corona discharges, small-scale electron streamers are formed. In the DBD mode of operation, the threshold electric field... 

Edge of heater ribbon visible at left (2). Vapor streamers from edges of heater ribbons (3). Fluctuating surface temperature. 

The action of an active intermediate oxidation product would explain another feature of the reaction. The reduction of silver ions by hydrazine is extremely sensitive to the presence of small amounts of copper. For example, a solution containing a mixture of silver nitrate, sodium sulfite and hydrazine which normally showed no sign of reduced silver for several minutes underwent almost immediate reaction when merely stirred with a clean copper rod. In the presence of gum arabic as stabilizer, streamers of colloidal silver passed out from the copper surface. Similarly, the addition of small amounts of cupric sulfate to a hydrazine solution eliminated the induction period of the reaction with silver chloride. 

The principle embodied in Mark 29 Anti-torpedo Device was as follows Two explosive streamers and a third streamer contg audio pickups sensitive to vibrations from the torpedo were to be trailed by a faired (joined so that external surfaces blend smoothly) cable attached to a paravane (See Note). When a torpedo passed over or under the detector streamer, one of the explosive streamers would be fired automatically to destroy the torpedo. The 2nd streamer would then be thrown automatically into the firing circle in readiness for a 2nd attack (Ref 2)... 

The condensate that collects on the cold surface is usually a completely homogeneous, or miscible, mixture of components. In general, the relative composition of the liquid components in the condensate is different from the composition in the vapor phase (except for an azeotropic mixture, where the condensate has the same exact molar concentration ratio as the vapor phase) [194]. The film that forms is not necessarily smooth but may show the appearance of streamers (or rivulets), waves, or droplets, depending on the particular mixture and its surface tension (which depends on the local wall temperature) [25,195,196]. If the condensate mixture is heterogeneous, or immiscible (as can occur when one component, for example, is aqueous and the other is organic), the pattern can be quite complex, looking somewhat like dropwise condensation [25,193,197]. These different condensate patterns affect the resulting fluid flow and heat transfer. 

Four principal patterns of convection were distinguished when pure liquids were employed cells, streamers, ribs, and vermiculated rolls. These names were chosen in an attempt to describe the actual appearance of the convection patterns and in accordance with historical designations. Examples are shown in Fig. 21. The patterns depicted there were exhibited in all of the liquids under various conditions. In particular, cells appeared to be the dominant patterns in all liquids for depths of 2 mm or less, and the cell size for the various liquids at the 1-mm and 2-mm depths is shown in Table VI. For a thin (< 2 mm) layer of given liquid evaporating into still air, the cell size increased with the depth of the liquid layer, and the flow which the cellular schlieren pattern represented was the same as that observed by Benard (see Fig. 3). These cells were quite immobile and generally neither grew nor decayed in size with time. A direct stream of dry nitrogen onto the surface of the liquid sharpened the cell peripheries and tended to reduce the cell size. 

The third pattern, ribs, often coexisted with that of streamers when the liquid was completely devoid of surface contamination. These ribs moved rapidly about among the streamers, traveled perpendicular to themselves, and could be either perpendicular or parallel to the streamers. As the depth of the fluid layer was increased, ribs often began to appear even if the principal pattern was still cellular. These ribs then persisted while the depth was increased still further, with the pattern evolving into one of the streamers interspersed with these fast-moving ribs. 

Fio. 22. Evaporative convection in cold streamers cold fluid plunges along distinct lines in the surface and warm fluid rises slowly in the area between the streamers (B12). 

Figure 4-8. Illustration of streamer propagation from a positive 2-em-diameter rod to a plane loeated at a dis-tanee of 1.5 m applied voltage 125 kV Equipotential surfaces are shown as fraetions of the total applied voltage.

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