Historical experience

Selection of incidents described was based on the availability of information, the kind and amount of material involved, and severity of damage. Accidents occurring on public property generally produce better published documentation than those occurring on privately owned property. 

The vapor cloud explosion incidents described below cover a range of factors  

Material properties Histories include incidents involving hydrogen (a highly reactive gas), propylene, dimethyl ether, propane, cyclohexane (possibly partly 

Most incidents discussed occurred several years ago, but it should be emphasized that such incidents still occur. More recent incidents include Celanese (1987), Shell (1988), Phillips (1989), and Exxon (1989). 

E)ocumentation of flash fires is scarce. In several accident descriptions of vapor cloud explosions, flash fires appear to have occurred as well, including those at Flixborough, Port Hudson, East St. Louis, and Ufa. The selection and descriptions of flash fires were based primarily on the availability of information. 

---

There are several widely used approaches for developing perspective about the significance of absolute risk estimates (Figure 16). The first approach is to compare the risk estimates to historical experience within your company, looking for similar events. Most companies have safety and loss recordkeeping programs that date back many years. But if directly related data are sparse, you may widen your comparison to extrapolate from near-miss incidents that could have caused the event of interest. You will not, however, frequently find solace from the company data—or even comparable industry data. 

The state of the knowledge is at the moment such that still in each particular case, the investigator should analyse and establish experimentally how important are, relative to each other, the effects 1) and 2) for the activity and the selectivity of a given multimetallic catalyst. It is an historical experience that when the explanation of the data is not immediately obvious, the authors offer as an "explanation" "an electronic (ligand) effect" (7). In this way it happened that the effect sub 1) has been most frequently proven to operate, while the effect sub 2) is the most frequently postulated... 

Human factors and ergonomics play a key role in the prevention of accidents. Some theories attribute up to 90% of all accidents are caused by human factor features. It is therefore imperative that an examination of human factors and ergonomics be undertaken to prevent fire and explosions at petroleum facilities since historical experience have also shown it is a major contributor either as a primary or underlining cause. 

TABLE 16. Historical experiments concerning the observed rate accelerations and selectivities of Diels-Alder reactions in different solvents ... 

For any new excipients, APIs or drug products (where new does not necessarily mean novel, but new to the receiving site) there are additional testing criteria, e.g. supplier audits, third-party contract laboratory audits, analytical method transfers, sample management/tracking, etc. For those key excipients, where there is on-site historical experience, it still behoves both parties to check whether the local grade/supplier used by the CMO is equivalent to that used by the supplier (Worsham, 2010). There are many examples of differences in excipient physical properties, e.g. particle size, which have been attributed to different excipient sources that could ultimately impact on the performance of those excipients in formulated products (Frattini and Simioni, 1984 Dansereau and Peck, 1987 Phadke et al., 1994 Lin and Peck, 1994). 

Many applications of the aminoglycosides have been of historical significance in genetics and microbiology. For example, mutations to streptomycin resistance were employed as counterselective genetic markers in the historic experiments of William Hayes that demonstrated the existence of bacterial conjugation and the requirement of donor (Hfr or F-b) and receptor (F—) species. ... 

Cockburn, Henderson, and Stern (1999) emphasize the importance of organizational factors and the distribution of power relationships within the firm for the speed at which new research methods are employed. Some firms are more suited to the new technology than others. The authors note that all their informants emphasized that differences in the historical experience of the firm, in their knowledge capital, were critically important in shaping the adoption decision (p. 19). 

The Court did not agree that the Supremacy Clause and historical experience could be applied to local sheriffs. The justices pointed out that any precedent applied only to state judges, not law enforcement officers. They found no evidence, at least until recent times, that Congress had asserted a power to commandeer local officials. Further, None of [the statements... 

Simonds, Merilyn. Code of Arms. Canadian Geographic, vol. 116, March-April 1996, pp. 44ff. Describes the gun scene in Canada, which has a reasonable number of guns but does not have the emotional attachment to them that many people in the United States have. Simonds reviews the different historical experiences that people in Canada and the United States have had with firearms. She also discusses events that have heated up the gun control debate in Canada. A related article gives a brief chronology of gun control in Canada. 

Adjuvant chemotherapy involves the use of antineoplastic drugs when surgery or radiation therapy has eradicated the primary tumor but historical experience with similar patients indicates a high risk of relapse due to micrometastases. Adjuvant chemotherapy should employ drugs that are known to be effective in the treatment of advanced stages of the particular tumor being treated. Adjuvant chemotherapy has played a major role in the cure of several types of childhood cancers as well as breast cancer, colorectal cancer, and osteosarcoma in adults. 

Kris, E., and Kurz, O. Die Legende vom Kunstler Ein geschichtlicher Versuch. Vienna Kristall, 1934 trans. Legend, Myth and Magic in the Image of the Artist An Historical Experiment. New Haven Yale Univ. Press, 1979. 

Probably the first major publication of a process model for the autoclave curing process is one by Springer and Loos [14]. Their model is still the basis, in structure if not in detail, for many autoclave cure models. There is little information about results obtained by the use of this model only instructions on how to use it for trial and error cure cycle development. Lee [16], however, used a very similar model, modified to run on a personal computer, to do a parametric study on variables affecting the autoclave cure. A cure model developed by Pursley was used by Kays in parametric studies for thick graphite epoxy laminates [18]. Quantitative data on the reduction in cure cycle time obtained by Kays was not available, but he did achieve about a 25 percent reduction in cycle time for thick laminates based on historical experience. A model developed by Dave et al. [17] was used to do parametric studies and develop general rules for the prevention of voids in composites. Although the value of this sort of information is difficult to assess, especially without production trials, there is a potential impact on rejection rates. 

Corrosion rates are expressed in terms of inches per year of surface wastage and are used to provide a corrosion allowance in the design thickness of equipment such as vessels and pipes. Operators will often use data based on historical experience from plant operations to aid them in determining appropriate corrosion allowances. Alternatively, corrosion charts are widely available that give corrosion rates for many combinations of materials of construction and process fluids, and normally a range of values will be provided for various process temperatures. In some instances, particularly where there is a mixture of chemicals present, appropriate data may not exist and corrosion tests may be necessary in order to determine the suitability of equipment. Operators should be able to demonstrate the use of corrosion allowances in equipment specification and design. The sources of data used should be traceable. 

Homonuclear decoupling is pretty much a historical experiment, as newer experiments such as 1D-TOCSY (Chapter 8) and 2D-COSY (Chapter 9) have replaced it. 

---