Leakage mechanisms

Another important leakage mechanism is a concentration-driven diffusive flux in contrast with the pressure-driven hydrodynamic flux considered previously. The flux of species A relative to the average molar velocity of all components is given by Fick s first law. 

The pore formation mechanism presented in Fig. 7 (45) is appealing for many reasons. It illustrates the significance of thermal fluctuations, because the pore is indeed induced by fluctuations in spontaneous salt ion concentrations in the vicinity of the membrane. Furthermore, the pore mediated ion leakage mechanism is very rapid, and it occurs in a collective manner through redistribution and diffusion of lipids around the pore. Also, recent data indicate that the pores also mediate flip-flop events across a membrane (46), which provides one plausible mechanism for lipid translocation, which in turn is of central importance in processes such as programmed cell death. Other dynamic processes in lipid systems are expected to be equally complex, which highlights the importance to understand the interplay between thermal fluctuations, physiologic conditions, and collective phenomena. 

The possibility of other leakage mechanisms taking place can depend on the seal architecture. For... 

A proper understanding of the above items, including maturation and filling history, formation pressure distributions, intra-reservoir communications, fault and top seal potentials, and leakage mechanisms, is considered essential for resource assessment, safe drilling of further explora-tion/delineation and production wells, and for reservoir management and production planning of the Njord Field. 

The interplay between reservoir and cap rock pore-pressures and vertical leakage mechanisms for the field has been further assessed by analysing the reservoir pore-pressure situation at the apex (i.e., the weak point ) of each hydraulic compartment (Fig. 13), and by relating the apex reservoir pore-pressures to the corresponding minimum fracture pressures of the cap rock (Fig. 14). The fact that the Spekk Formation represents both the main source rock and cap rock for the Njord Field is a key aspect in these considerations. 

The reactor coolant pump is a vertical, single speed (1500 rpm), bottom suction, horizontal discharge casing unit with controlled leakage mechanical shaft seals and driven by a... 

Tlie indi ddual cells are assembled into batteries after a leakage test to check for faulty welding joints in steel containers or cracks and improper seals in the plastic encased cells. Cells that are to be delivered without electroltye are emptied after the fomiation cycles. Tlie steel-cased cells hav e to be separated by mechanical means to prevent intercell shorts and are often assembled into wooden crates. Tlie cells in plastic cases can be cemented together or strapped with tape. 

Mechanical Face Seals This type of seal forms a running seal between flat precision-finished surfaces. It is an excellent seal against leakages. The seahng surfaces are planes perpendicular to the rotating shaft, and the forces that hold the contact faces are parallel to the shaft axis. For a seal to function properly, there are four sealing points ... 

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