Catastrophe generalized

For compressors in general and for some types in particular, the cleanliness of the gas stream is the key factor in a reliable operation. Moisture or liquids in various forms may be the cause of an early failure or in some-cases a catastrophic failure. Corrosive gases require material considerations and yet even this may not entirely solve the loss of material issue that can certainly cause early shutdowns or failures and high maintenance cost. Fouling due to contaminants or reactions taking place internal to the ( i-pressor can cause capacity loss and the need for frequent shutdowns. 

As with any analytical method, the ability to extract semiquantitative or quantitative information is the ultimate challenge. Generally, static SIMS is not used in this mode, but one application where static SIMS has been used successfully to provide quantitative data is in the accurate determination of the coverage of fluropolymer lubricants. These compounds provide the lubrication for Winchester-type hard disks and are direaly related to ultimate performance. If the lubricant is either too thick or too thin, catastrophic head crashes can occur. 

While generally only a single contingency is considered for design purposes, there may be situations where two or more simultaneous contingencies should be taken into account e.g., if there is some remote interrelationship between them, and pressures or temperatures developed could result in catastrophic failure. Such contingencies are also considered, and the 1.5 Times Design Pressure rule may be applied in this situation. 

In some cases where the ASME Code woidd not require pressure relief protection, the 1.5 Times Design Pressure Rule is apphcable. This rule is stated as follows Equipment may be considered to be adequately protected against overpressure from certain low-probability situations if the pressure does not exceed 1.5 times design pressure. This criterion has been selected since it generally does not exceed yield stress, and most Ukety would not occur more frequently than a hydrostatic test. Thus, it will protect against the possibility of a catastrophic failure. This rule is applied in special situations which have a low probability of occurrence but which cannot be completely ruled out. 

The greatest concern that most members of the general public have about nuclear energy is the possibility of a catastrophic accident such as occurred in 1986 at Chernobyl in the Ukraine. If reactors have... 

Sulfidation is analogous, but catastrophic sulfidation is common because of the generally lower melting points of sulfides than corresponding oxide. This is especially true in the case of nickel alloys, when a nickel/nickel sulfide eutectic is formed. 

Generally, the most important reaction is that of tantalum with oxygen, since it tends to form oxides when heated in air. Reaction starts above 300°C and becomes rapid above 600°C . The scale is not adherent, and if the oxidised material is heated above 1000°C oxygen will diffuse into the bulk of the material and embrittle it. At 1200°C catastrophic oxidation attack takes place at a rate of about 150 mm/h Oxygen is not driven off by heating alone, but in vacuum above 2300°C it is removed as a suboxide. The first step of the conversion mechanism of tantalum into oxide was shown to occur by the nucleation and growth of small plates along the 100) planes of the BCC metaP. ... 

System faults fall into two general classes the sudden catastrophe of a mechanical breakdown and the slow fall-off of performance which can be detected as a malfunction in its early stages but will also lead to a breakdown if not rectified. Identification of the first will be obvious. To track down the cause of a malfunction will be more complicated. 

A Category 3 incident is an emergency of major proportions. It may have escalated from a smaller incident or arise instantaneously, e.g. due to a confined or unconfined vapour cloud explosion or a catastrophic failure of a storage vessel. The response from the emergency services will again need to be predetermined by pre-planning. Extensive evacuation of the general public may be required. 

It should be noted that Fig. 25 is not exhaustive, because the catastrophe map for general L in Fig. 2 of Ref. [14] shows a narrow band that is bounded below by the junction between regions III and IV of the L = 0 catastrophe map in Fig. 24 and above by a line of cusps, parametric on L. The nature of the monodromy in this region remains to be investigated. 

The last problem of this series concerns femtosecond laser ablation from gold nanoparticles [87]. In this process, solid material transforms into a volatile phase initiated by rapid deposition of energy. This ablation is nonthermal in nature. Material ejection is induced by the enhancement of the electric field close to the curved nanoparticle surface. This ablation is achievable for laser excitation powers far below the onset of general catastrophic material deterioration, such as plasma formation or laser-induced explosive boiling. Anisotropy in the ablation pattern was observed. It coincides with a reduction of the surface barrier from water vaporization and particle melting. This effect limits any high-power manipulation of nanostructured surfaces such as surface-enhanced Raman measurements or plasmonics with femtosecond pulses. 

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