Stability zones

The air jet textured yam process is based on overfeeding a yam into a turbulent air jet so that the excess length forms into loops that are trapped in the yam stmcture. The air flow is unheated, turbulent, and asymmetrically impinges the yam. The process includes a heat stabilization zone. Key process variables include texturing speed, air pressure, percentage overfeed, filament linear density, air flow, spin finish, and fiber modulus (100). The loops create visual and tactile aesthetics similar to false twist textured and staple spun yams. 

Figure 10-2. Baffle added to straight-walled duet to ereate flame stabilization zone.

Pourbaix s pioneering work on the graphical presentation of gas-metal equilibria and the concept of stability zones and their boundaries between the various stable compounds lead to the second type of diagrams. Figure 7.65 shows a Pourbaix plot of the log P02 system against the reciprocal... 

By plotting a graph between number of neutrons and protons for the nuclei of various elements it has been found that most stable nuclei (non-radioactive nuclei) lie within the shaded area which is called the zone or belt of stability because it contains the stable nuclei. Nuclei that fall above or below this belt are unstable. Nuclei that fall above the stability belt have more neutrons while those lying below have more protons. Such unstable nuclei would attain stability by undergoing change that would produce a nucleus with n/p ratio within the stability zone. 

When a positive ion enters the filter, maintained under vacuum, at the origin O, its velocity vector in xyz space will determine its trajectory. The central portion of the quadrupole behaves like a tunnel in the O-z axis. The walls of the tunnel can either attract or repel an ion depending on the ion s position. The two positively charged electrodes will focus the ion in the O-z axis, corresponding to a potential valley (stability zone) while the two negatively charged electrodes will have a defocusing effect (potential maximum, unstable y-O-z plane). 

Hydrate formation from gas dissolution of rising water Hyndman and Davis (1992) proposed that as methane-unsaturated water rises, it becomes saturated at lower pressures. As the saturated (or supersaturated) water passes through the phase stability zone, hydrate formation occurs without a free gas zone. This model results in a maximum hydrate concentration at the three-phase (BSR) boundary with a successively lower hydrate amounts above the BSR as was shown to be the case in Cascadia Margin ODP Drill Sites 889 and 890 by Hyndman et al. (1996). 

Ginsburg and Soloviev (1998, pp. 150-151) state that the BSR is the most widely used indirect indication of gas hydrates. The most important evidence of the hydrate caused nature of the BSR is the coincidence of temperature and pressure calculated at it s depth with the equilibrium temperatures and pressure of gas hydrate stability. The association with the base of the hydrate stability zone is beyond question. ... 

In Site 995, as in Site 994, there is a discrepancy between the inferred lowest hydrate level (450 mbsf) and the experimentally predicted base of the stability zone (541-577 mbsf). Possible reasons for this discrepancy are discussed after the Site 997 discussion. 

Similar to Sites 994 and 995, six indicators of hydrate were present (1) large gas exsolution from cores, (2) high methane sediment concentration, (3) BSRs, (4) low interstitial-water chlorinity, (5) low core temperatures (although IR technology was introduced just after this hydrate leg), and (6) P-wave velocity logs and resistivity logs. As in Sites 994 and 995, there was a discrepancy between the indicated base of the inferred hydrate zone (452 mbsf) and the phase-equilibria stability zone (491 to 524 mbsf). 

The curve of 02 accumulation shows that short contact times, at which the methane oxidation rate is low, are enough for complete H202 dissociation. However, as observed from shapes of 02 and CH3OH accumulation curves, methanol yield increases synchronously with 02 yield decrease, and from the moment r = 10.2 s both curves stabilize. Such stabilization and synchronization of catalase and monooxygenase reaction product yields is the experimental proof of their interaction, displayed by chemical conjugation. The existence of the stabilization zone of 02 and CH3OH yields is associated with full H202 dissociation. 

The information contained in this pe-pH diagram is particularly useful in the determination of stability zones for solid phase metal sulfides (Example 3.14). For example, it is the reduction of sulfate to sulfide which determines the stability field of pyrite (FeS2)-... 

As oil and gas exploration extends into progressively deeper waters, the potential hazard posed by gas hydrates to operations is gaining increasing recognition. Hazards can be considered as arising from two possible events (1) the release of high-pressure gas trapped below the hydrate stability zone, or (2) the destabilization of in situ hydrates. A major issue is how gas hydrates alter the physical properties of sediment. The link between seafloor failure and gas... 

Flexnip" 2. Diffusion zone 3. Expanding zone 4. Stabilizing zone. 

Figure 9-18. Dimensa mercerizing machine cloth run diagram. 1. impregnating zone 2. cooling and reaction zone 3. stenter frame 4. stabilizing zone 5. washing and neutralising zone.

Select a trial value of stabilized-zone thickness. 

Figure D.1 ASPD versus stabilized-zone thickness for tunnel axis depth of 10.5m.

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