Contributory factors

Extrapolation from these two sets of values to C4 gives a (C4H,o) = 40-5 A for n-butane, which may be compared with the figure of 44-4 A (with a standard deviation of 4 A ) given in McClellan and Harnsberger s final list of recommended values and the value of 40 A found by Davis for n-butane on graphitized carbon at 195 K. A contributory factor to the variation in a -values is that the value of c tends to be low, e.g. on CaCOj (p. 251) c for butane is around 25. 

No accident has a simple cause. In this case a contributory factor was the inexperience of the operator, who had to ask someone to show him how the quench system worked. It had not been used for several years. Emergency equipment is usually used infrequently, and without regular training, people forget (or never learn) how to use it [6]. 

Error analysis techniques can be used in accident analysis to identify the events and contributory factors that led to an accident, to represent this information in a clear and simple manner and to suggest suitable error reduction strategies. This is achieved in practice by identification of the causal event sequence that led to the accident and the analysis of this sequence to identify the root causes of the system malfunction. A discussion of accident analysis techniques is included in Chapter 6. 

The information gathered relating to the incident was used to identify the sequence of causes and consequences which led to the mischarge. From the resulting variation tree (see Figure 7.8) two critical points and their contributory factors can be identified. 

These scenarios are borne out in practice, and where boiler waterside problems are identified, there almost always is more than one contributory factor. Investigation usually reveals a chain of cause and effect. Typically, any specific causative agent identified (such as oxygen) affects more than one part or component of the overall system. 

Burkholderia (formeriy Pseudomonas) cepacia is intrinsically resistant to a number of biocides, notably benzalkonium chloride and chlorhexidine. Again, the outer membrane is likely to act as a permeability barrier. By contrasL Ps. stutzeri (an organism implicated in eye infections caused by some cosmetic products) is invariably intrinsically sensitive to a range of biocides, including QACs and chlorhexidine. This organism contains less wall muramic acid than other pseudomonads but it is imclear as to whether this could be a contributory factor in its enhanced biocide susceptibility. 

The total wet deposition flux consists of 2 contributory factors. The first derives from the continuous transfer of Hg to cloud water, described by chemistry models. There are 2 limiting factors 1) the uptake of gas phase Hg(0), which is regulated by the Hemy s corrstant and 2) the subsequent oxidation of Hg(0) to Hg(ll), which is governed by reaction rate constants and the irritial concentratiorrs of the oxidant species. The total flirx depends on the hquid water content of the cloud and the percentage of the droplets in the cloud that reach the Earth s surface. 

A bottle of the dichloride exploded violently while on a bench. No cause was established, but diffusive ingress of moisture, or an intramolecular Friedel-Crafts reaction, both of which would form free hydrogen chloride, seem possible contributory factors. 

A large dump of copper pyrites ore ignited after heavy rain. The thick layer (6-7 m) and absence of ventilation were contributory factors to the accelerating aerobic oxidation which finally led to ignition. 

Anaemia often becomes a characteristic feature of several chronic diseases, such as rheumatoid arthritis. In most instances this can be linked to lower than normal endogenous serum EPO levels (although in some cases a deficiency of iron or folic acid can also represent a contributory factor). Several small clinical trials have confirmed that administration of EPO increases haematocrit and serum haemoglobin levels in patients suffering from rheumatoid arthritis. A satisfactory response in some patients, however, required a high-dose therapy that could render this therapeutic approach unattractive from a cost benefit perspective. 

The ability of an SSRI, or any antidepressant, to inhibit or induce the activity of the cytochrome P450 (CYP450) enzymes can be a significant contributory factor in determining its capability to cause a pharmacokinetic drug-drug interaction. 

This may be partly the result of increased steric crowding in the transition state of transalkylation. Another contributory factor to the increased selectivity in ZSM-5 is the higher diffusion rate of ethylbenzene vs m-/o-xylene in ZSM-5 and hence a higher steady state concentration ratio [EB]/[xyl] in the zeolite interior than in the outside phase. Diffusional restriction for xylenes vs ethylbenzene may also be indicated by the better selectivity of synthetic mordenite vs ZSM-4, since the former had a larger crystal size. 

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