Leakage tendencies

ASTM Method D 1263-61, Leakage Tendencies of Automotive Wheel Bearing Greases, ASTM Standards Book, Part 17—Petroleum Products, American Society for Testing and Materials, Philadelphia. 

In most cylindrical carbon—zinc cells, the zinc anode also serves as the container for the cell. The zinc can is made by drawing or extmsion. Mercury [7439-97-6J has traditionally been incorporated in the cell to improve the corrosion resistance of the anode, but the industry is in the process of removing this material because of environmental concerns. Corrosion prevention is especially important in cylindrical cells because of the tendency toward pitting of the zinc can which leads to perforation and electrolyte leakage. Other cell types, such as flat cells, do not suffer as much from this problem. 

One drawback of the spring is the need for relatively low shaft speeds because of a natural tendency of the components to distort at high surface speeds. This makes the spring push harder on one side of the seal than the other, resulting in an uneven liquid film between the faces. This causes excessive leakage and wears at the seal. 

In recent years there has been a tendency to use a.c. in preference to d.c. for industrial purposes, but d.c. systems may still be operating in shipyards, steelworks and similar sites for motive power and also for mobile cranes, lighting and control equipment. The running rails and mountings of such systems are usually in close contact with the earth and severe leakages can be expected to occur, either accidently or eis a result of deterioration with age. 

Extractant leakage from the pores of the polymeric membrane in SLM is due to osmotic flow of massive quantities of water through the membrane. Membrane stability decreases with increasing osmotic pressure gradient and depends upon composition of the SLM system. A high tendency to solubilize water, low extractant/aqueous interfacial tension, and high wettability of polymeric membrane leads to less stable SLMs. The following measures have been proposed for improvement of stability ... 

Maintaining an interface immobilizing pressure difference across the porous membrane in a direction and of a magnitude effective to oppose the tendency of leakage [83,84]. 

The syrups made prior to casting (and final polymerizalion) can be stored safely al a controlled temperature until required. The preparation of syrups In advance shortens the time in the mold, decreases the tendency for leakage from the molds, and greatly minimizes the chance of dangerous runaways. 

What cultural and patient acceptability factors may be important, for example, a tendency for the preparation to leak following initial application Vaginal delivery may not be universally acceptable in all cultures, and within cultures the preference for systems that can be self-inserted and removed, or considerations relating to leakage, will vary considerably. 

In case of leakage compensation, there is a strong tendency to achieve zero leakage for economical reasons. But very low leakage enclosures (and without a heat exchanger to remove internal thermal losses) tend to exceed the maximum pressure differential, e.g. of 300 Pa (=3.0mbar) during operation under load. 

Since the chemical potential of (A) is fixed by the cathodic reaction at (III), a chemical potential gradient of (A) exists inside product (D). This causes an open circuit internal electric field to build up to oppose the tendency of (A+) to move across product (D). However, product (D) is a mixed conducting product. As in a scale product, the electronic leakage current weakens the internal electric field in (D). Thus, the electrochemical potential gradient in Eqn. 24 exists to move (A+) from location (II) to location (III) to react with vapor phase. 

Tile construction is not used to any great extent for very aggressive liquid corrosives because the tile and the mortar joints are relatively thin approximately V2 in. deep) and are somewhat porous. These structures, therefore, have a tendency to weep or leak. Other factors which contribute to this tendency are the lack of a membrane and the susceptibility of the Portland cement core to attack by acidic media. Also, because the tiles are essentially the forms for the concrete and are not removed after the concrete cures, controlling the quality of the concrete wall by visually identifying stone pockets, pour lines, etc., is impossible. Structural tile vessels are, therefore, used in stock tanks, pulp storage tanks, washers, etc., where some leakage can be tolerated or the solids in the contained media will plug leaks. 

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