The Traditional Approach

The traditional method of essential oil analysis is to extract the plant material by steam distillation or with solvent and then fractionally distil the oil or extract and isolate individual components by chromatographic techniques for subsequent identification by spectroscopic methods. At each step the odour of the fractions and isolates is assessed and those with the desired characteristics are investigated further. To answer the enquiry about the key odour components of broom absolute, first a sample of the absolute that is of an acceptable odour quality is obtained. The absolute is the alcoholic extract of the concrete, which is itself the solvent extract of the flowers of Spartium junceum, Spanish broom, often referred to by its French name Genet. The odour of any natural extract can vary according to the geographical origin and quality of the plant material, the time of year it is harvested and the extraction method used. If no sample of adequate quality is commercially available then the fresh flowers would be obtained from the plant and the extraction carried out in the laboratory. 

If materials are found that have an interesting odour, but that cannot be identified by GC-MS, they are isolated by preparative techniques such as preparative high-performance liquid chromatography (HPLC) or preparative GC and their structures determined by nuclear magnetic resonance (NMR) which, in most cases, is able to provide an adequate identification. As the compositions of the chosen fractions and subfractions are determined, the perfumer tries to create an accord which adequately represents the odour of the original material by reconstructing the fractions from their individual components. 

Compound 42 was synthesized following the pubhshed method [40], The yield of the mCPBA oxidation of 42 to afford 6 was less than 50% and involved a cumbersome isolation procedure. This oxidation is the most environmentally unfriendly step in the synthesis of 6. The addition of one gram of oxygen to the sulfide generates more than ten grams of m-chlorobenzoic acid as a waste. Thus, this transformation is not green, and furthermore mCPBA is an expensive and shock-sensitive material. 

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Traditional vs regression approach to automatic material characterization The traditional approach to automatic material characterization is based on physical reasoning where a. set of features of the signals that we assume to be the most relevant for solving the characterization problem is. selected. However, in situations with a complicated relation between the measurements and the material property to be characterized, this approach is not always applicable due to limited understanding of the underlying physical relations. 

We should also note that most of todays data acquisition systems are capable of producing enormous amounts of data which the traditional approach does not exploit for anything but verification of different ways to extract and combine features. To search in the. space of all such combinations is however a tremendous task. 

By proper design of experiments, guided by a statistical approach, the effects of experimental variables may be found more efficiently than by the traditional approach of holding all variables constant but one and systematically investigating each variable in turn. Trends in data may be sought to track down nonrandom sources of error. 

Discovery. The traditional approach to new pesticide discovery was to make iatuitive changes ia the substitueats oa a promising primary chemical stmcture. Initially, materials from any source were subjected to screening for biological activity as iasecticides, herbicides, or fungicides. 

Selective Catalytic Reduction of Nitrogen Oxides The traditional approach to reducing ambient ozone concentrations has been to reduce VOC emissions, an ozone precurssor. In many areas, it has now been recognized that ehmination of persistent exceedances of the National Ambient Air Qnality Standard for ozone may reqnire more attention to reductions in the other ingredients in ozone formation, nitrogen oxides (NOJ. In such areas, ozone concentrations are controlled by NO rather than VOC emissions. 

Process safety differs from the traditional approach to accident prevention in a number of ways (Lees, Loss Prevention in the Process Industries, 2ded., Butterworth-Heinemann, 1996, p. 1.8) ... 

Fig. 2.1. The traditional approach to the study of mechanical responses of shock-compressed solids is to apply a rapid impulsive loading to one surface of a diskshaped sample and measure the resulting wave propagating in the sample. As suggested in the figure, the wave shapes encountered in shock-loaded solids can be complex and may require measurements with time resolutions of a few nanoseconds.

From the organizational view of accident causation presented in the previous section, it will be apparent that the traditional approach to human error, which assumes that errors are primarily the result of inadequate knowledge or motivation, is inadequate to represent the various levels of causation involved. These contrasting views of error and accident causation have major implications for the way in which human error is assessed and the preventative measures that are adopted. 

This is partly because the traditional approach is well known and documented in the industry, whereas the other approaches have received very little application to date. In addition, despite the successes of the traditional approach in the area of occupational safety, it may be less applicable in areas such as the prevention of major chemical accidents. 

The traditional approach, because it sees the major causes of errors and accidents as being attributable to individual factors, does not encourage a consideration of the underlying causes or mechanisms of error. Thus, accident data-collection systems focus on the characteristics of the individual who has the accident rather than other potential contributory system causes such as inadequate procedures, inadequate task design, and communication failures. 

The successes of the traditional approach have largely been obtained in the area of occupational safety, where statistical evidence is readily available concerning the incidence of injuries to individuals in areas such as tripping and falling accidents. Such accidents are amenable to behavior modification approaches because the behaviors that give rise to the accident are under the direct control of the individual and are easily predictable. In addition, the nature of the hazard is also usually predictable and hence the behavior required to avoid accidents can be specified explicitly. For example, entry to enclosed spaces, breaking-open process lines, and lifting heavy objects are known to be potentially hazardous activities for which safe methods of work... 

Having described the underlying philosophy of the traditional approach to accident prevention, we shall now discuss some of the specific methods that are used to implement it, namely motivational campaigns and disciplinary action and consider the evidence for their success. We shall also discuss another frequently employed strategy, the use of safety audits. 

The traditional approach to CPQRA only considers human failures to perform required functions (usually errors of omission). However, many critical errors arise from misdiagnoses (mistakes) leading to erroneous, inappropri-... 

An alternative to the traditional approach is to generate the electronic states as needed during the dynamics. This has been done for atomic collisions, where detailed calculations and comparisons with experimental results are possi-ble.(4-8) General treatments of the coupling of electronic and nuclear motions in molecular systems can be done in a variety of formulations. In particular, Ohrn, Deumens and collaborators have implemented a general variational treatment in... 

The traditional approach to optimize a process is schematically shown in Figure 2 its principle elements are the development of a model, model validation, definition of an objective function and an optimizing algorithn. The "model" can be (a) theoretical, (b) empirical or (c) a combination of the two. 

As is well known, we can consider the ensemble of many molecules of water either at equilibrium conditions or not. To start with, we shall describe our result within the equilibrium constraint, even if we realize that temperature gradients, velocity gradients, density, and concentration gradients are characterizations nearly essential to describe anything which is in the liquid state. The traditional approaches to equilibrium statistics are Monte Carlo< and molecular dynamics. Some of the results are discussed in the following (The details can be found in the references cited). 

The practical aspects of computers lie in their ability to collect, simplify, and provide access to massive amounts of data easily The traditional approach of patiently waiting for held data, where entry often takes weeks to months, does not take advantage of currently available technology. Even with web-based... 

In the traditional approach of person-to-person telephone call, the SC indicates the subject to be randomized and is asked protocol-specific questions collectively known as the randomization form. An eligible subject whose informed consent has been received and verified for accuracy and complete-... 

This will extend, and partially replace, the traditional approach to biomedical research that is based on studying living cells or tissues in vitro, or on obtaining data from human volunteers in vivo, by introducing in silico experiments (a term, derived from the currently prevaihng sihcon-based computer chips). 

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