Intermittency zone

Now visualize the action of a submerged jet of air in liquid. At very low air flow velocities, the bubbles are large. They rise as independent bubbles at the orifice. When the velocity of air through the orifice increases, the air projects as a cone into the liquid and small bubbles shear off. The maximum velocity is reached when the ratio of absolute hydrostatic pressure outside the orifice divided by the absolute air pressure in the orifice is 0.528. This determines sonic velocity. Four regions of the air cone or jet are conceptually drawn in Fig. 11. Region I is called the potential core of air with a uniform velocity. The outermost annular cone, Region II, is an intermittency zone in... 

Intermittent (I) - In this flow pattern the liquid inventory in the pipe is non-uniformly distributed axially. Plugs or slugs of liquid that fill the pipe are separated by gas zones that contain a stratified liquid layer flowing along the bottom of the... 

Butturini A, Bernal S, SahaterS, SahaterF (2002) The influence of riparian-hyporheic zone on the hydrological responses in an intermittent stream. Hydrol Earth Syst Sci 6 515-526... 

Leaching of nuclides implanted into adjacent minerals has been suggested for the supply of Rn into the vadose zone. Where there are intermittent undersaturated conditions, i.e., in soils or rocks where the water table lowers seasonally, the low stopping power of air allows atoms ejected from minerals to be implanted across pore spaces. These atoms will then be available for leaching... 

Flow injection analysis (FIA) (Ruzicka and Hansen), since 1975 In continuous flow, stopped flow or with merging zones (FIA scanning or intermittent pumping) Adapted voltammetric electrodes Membranes for Partial dialysis Membrane amperometry (Clark) Differential techniques (Donnan) Computerization, including microprocessors Special measuring requirements in plant control (to avoid voltage leakage, etc., Section 5.5)... 

Flow injection analysis (F1A). In this technique, introduced by Ruzicka and Hansen, a small amount of sample is injected into a liquid flow (see Fig. 5.16), which apart from being automated is normally continuous, but can include the use of stopped-flow, merging zones extraction techniques in addition to FIA scanning and methods based on intermittent pumping89. The principles of FIA and the versions just mentioned will now be briefly discussed on the basis of the excellent review of Ruzicka and Hansen89 in order to understand the appli-cational possibilities of electrochemical detection in this technique. 

Even where it is not occluded, the mineral surface may not be reactive. In the va-dose zone, the surface may not be fully in contact with water or may contact water only intermittently. In the saturated zone, a mineral may touch virtually immobile water within isolated portions of the sediment s pore structure. Fluid chemistry in such microenvironments may bear little relationship to the bulk chemistry of the pore water. Since groundwater flow tends to be channeled through the most permeable portions of the subsurface, furthermore, fluids may bypass many or most of the mineral grains in a sediment or rock. The latter phenomenon is especially pronounced in fractured rocks, where only the mineral surfaces lining the fracture may be reactive. 

Plain-orifice atomizers are widely used for injecting liquids into a flow stream of air or gas. The injection may occur in a co-flow, a contra-flow, or a cross-flow stream. The best known application of plain-orifice atomizers is perhaps diesel injectors. This type of injectors is designed to provide a pulsed or intermittent supply of fuel to the combustion zone for each power stroke of the piston. As the air in the combustion zone is compressed by the piston to a high pressure, a very high pressure (83-103 MPa) is required to allow the fuel to penetrate into the combustion zone and disintegrate into a well-atomized spray. 

Catalyst formulations for ATR fuel processors mainly depend on the fuel and the operating temperature. ATR catalysts are required to be active simultaneously for hydrocarbon oxidation and SR reactions, be robust at high temperatures for extended periods and be resistant to sulfur poisoning and carbon deposition, especially in the catalytic zone that runs oxygen limited [33]. Moreover, they must be resistant to intermittent operation and cycles, especially in start-up and shut-down steps. 

These furnaces may operate batchwise or continuous. In the batch, intermittent, or periodic types, the content is heated at the desired temperature for the stipulated time and then removed. In the continuous type, the charge moves at a predetermined rate through one or more heating zones to emerge in most cases at the end opposite the point of entry. Figures 9 and 10 are representative examples of typical, industrial refractory-wall furnaces. 

This area is 20 km northeast of Poti, to the West Chaladidi anticline of the Pontain-Meotian (Miocene) sediments. It is in the lower part of the above-mentioned Ochamchire-Kulevi block (3), near the south border of (III) the intermountain cavity zone, at the southwest edge of the Poti-Abedati and the Senaki-Tsaishi. On the Poti-Abedati fail line the Abedati, Nokalakevi and the Eki mountain over thrust sheet folds are displayed intermittently, which corresponds to the lower structural floor disjunctive break zones [9]. On the mentioned fail line, from the northeast to southwest, the relocation of epicentres of the Samegrelo earthquake (1941) is specified. 

The second case in this category of creep crack growth with a cohesive zone associated with viscous interfaces is the work of Nair and Gwo.32,53 Nair and Gwo32 considered intermittent crack growth whereas continuous crack growth was considered in the latter study. The principal assumption in these studies was that the stress field in the creep zone follows the ffR-field or RR-field (see Section 10.2) with applied K replaced by Keff. This is only a first approximation, because, as mentioned earlier, these crack tip fields were originally derived for traction-free crack surfaces. 

---