Rate of rupture

A characteristic parameter of the process is the ratio of the overall rate of erosion relative to the overall rate of rupture given by... 

E is still the modulus of elasticity. The E is assumed to be independent of force, rate of rupture, and so on. It has been pointed out recently99 that the wedge, unless it advances extremely slowly, is likely to cause vibrations (flexure waves) in the specimen which would necessitate an alteration of Eq. (52). 

When ebonite, bakelite, and similar materials were used, ignitions were more easily obtained than with the metals. No significant differences occurred in the sensitivity with the different materials. Kinoshita and Arimura believed that ignition with emery was by a different mechanism than by ebonite. They considered the rate of rupture of single crystals, rate of displacement between particles, and heat dissipation by the friction surfaces. When ground glass was added to the explosive, the results obtained with ebonite approximated those obtained with emery. 

In order to demonstrate rates of hydrolytic rupture of S-O-P bonds in condensed sulfate-phosphates, the variations of amounts of the combined sulfates with time are shown in Table XIV. There is a considerable increase in the rate of rupture of S-O-P bonds with increasing temperature. 

In some other theories, it has been suggested that the crack tip always remains covered with an oxide and the film is only periodically ruptured by emergence of slip steps. It has also been suggested that the crack tip remains bare because the rate of rupture of the oxide film is higher than the rate of repassivation of the film. In general, the rate of attack is determined by stress (applied or residual), electrochemical potential, total strain rate and specific ions and effect of solute segregates. 

There have been some studies of the equilibrium shape of two droplets pressed against each other (see Ref. 59) and of the rate of film Winning [60, 61], but these are based on hydrodynamic equations and do not take into account film-film barriers to final rupture. It is at this point, surely, that the chemistry of emulsion stabilization plays an important role. 

Sealless pumps rely on the process fluid to lubricate the bearings. If the wear rate of the bearings in the fluid being handled is not known, the bearings can wear unexpec tedly, causing rupture of the can. 

Under cyclic or repeated stress conditions, rupture of protective oxide films that prevent corrosion takes place at a greater rate than that at which new protec tive films can be formed. Such a situation frequently resiilts in formation of anodic areas at the points of rupture these produce pits that serve as stress-concentration points for the origin or cracks that cause ultimate failure. 

Metals Successful applications of metals in high-temperature process service depend on an appreciation of certain engineering factors. The important alloys for service up to I,I00°C (2,000°F) are shown in Table 28-35. Among the most important properties are creep, rupture, and short-time strengths (see Figs. 28-23 and 28-24). Creep relates initially applied stress to rate of plastic flow. Stress... 

For ratings of 25(300 A and above it is possible that the fault level of the system may exceed the rupturing capacity of the available interrupting devices. To reduce the fault level in such cases, ctirrent limiting series reactors can be provided with the btis system, as noted above and ilhistrated in Fiszttre 3 1.8. 

An example of the application of molecular mechanics in the investigation of chemical reactions is a study of the correlation between steric strain in a molecule and the ease of rupture of carbon-carbon bonds. For a series of hexasubstituted ethanes, it was found that there is a good correlation between the strain calculated by the molecular mechanics method and the rate of thermolysis. Some of the data are shown in Table 3.3. 

At high rates of strain, or when complete disentanglement cannot occur when M > M, bond rupture occurs randomly in the network and the percolation parameter p becomes dominated by chain ends such that... 

Thermal runaway is a partieular problem in unsteady state bateh reaetions, where the rate of reaetion and, therefore, the rate of heat produetion varies with time. The eonsequenees of thermal runaway are sometimes severe as in the ineidents at Seveso [3]. In this ease, a bursting disk ruptured on a reaetor. The reaetor was used to manu-faeture triehlorophenol at a temperature of 170-185°C and was heated... 

A runaway reaction occurs when an exothermic system becomes uncontrollable. The reaction leads to a rapid increase in the temperature and pressure, which if not relieved can rupture the containing vessel. A runaway reaction occurs because the rate of reaction, and therefore the rate of heat generation, increases exponentially with temperature. In contrast, the rate of cooling increases only linearly with temperature. Once the rate of heat generation exceeds available cooling, the rate of temperature increase becomes progressively faster. Runaway reactions nearly always result in two-phase flow reliefs. In reactor venting, reactions essentially fall into three classifications ... 

An 800-gal reaetor eontaining a styrene mixture with a speeifie heat of 0.6 eal/gm °C has a 10-in. rupture disk and a vent line with equivalent length = 400. The vessel MAWP is 100 psig and the rupture disk set pressure is 20 psig. The styrene mixture had a self-heat rate of 60°C/min at 170°C as it is tempered in a DIERS venting test. Determine the allowable reaetor mixture eharge to limit the overpressure to 10% over the set pressure. 

Explosion rupture disk device A rupture disk deviee designed for use at high rates of pressure rise. 

An operator was told to add a reactant over a certain period of time. He started to add it too slowly. Finding that he was getting behind, he added the rest too quickly, and a runaway occurred. Fortunately, in this case, the relief device controlled the situation, and the reactor did not rupture, though product was wasted. It may be necessary to specify the rate of addition as well as the time of addition. 

Where e.xperience indicates a reiisoiiable potential for equipment failure (such as a tank overflow, rupture, or leakage), the plan is to include a prediction of the direction, rate of flow, and total quantity of oil that could be discharged from the facility as a result of each major type of failure... 

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