Types of Results

The Zerner s INDO method (ZINDO) is also called spectroscopic INDO (INDO/S). This is a reparameterization of the INDO method specihcally for the purpose of reproducing electronic spectra results. This method has been found to be useful for predicting electronic spectra. ZINDO is also used for modeling transition metal systems since it is one of the few methods parameterized for metals. It predicts UV transitions well, with the exception of metals with unpaired electrons. However, its use is generally limited to the type of results for which it was parameterized. ZINDO often gives poor results when used for geometry optimization. 

An important and difficult task is concisely translating your requirements into study objectives. For example, if you need to decide between two methods of storing a hazardous chemical in a plant, the analysis objective should precisely define that what is needed is the relative difference between the methods, not the more general I want to know the risk of these two storage methods. And asking your QRA team for more than is necessary to satisfy your particular need is counterproductive and may create unnecessary liabilities. For any QRA to efficiently produce the necessary types of results, you must clearly communicate your requirements... 

A multitude of analysis techniques and models have been developed to aid in performing these four steps (Figure 7). Many references exist for specific methods, and several recent publications give specific advice and how to details for the various techniques. You will not have to select specific techniques—your QRA team will do that. But you must appreciate the types of results available from each class of techniques. 

The general procedures for the preparations of half-esters of diols are not usually very efficient in that both unreacted diol and diester are present along with the desired half-ester. Unfortunately, the present example is no exception but is included as an illustration of the type of results that can be expected under these circumstances. The diol employed for this reaction is prepared in Chapter 5, Section II. 

It may be felt that the initiation of a stress-corrosion test involves no more than bringing the environment into contact with the specimen in which a stress is generated, but the order in which these steps are carried out may influence the results obtained, as may certain other actions at the start of the test. Thus, in outdoor exposure tests the time of the year at which the test is initiated can have a marked effect upon the time to failure as can the orientation of the specimen, i.e. according to whether the tension surface in bend specimens is horizontal upwards or downwards or at some other angle. But even in laboratory tests, the time at which the stress is applied in relation to the time at which the specimen is exposed to the environment may influence results. Figure 8.100 shows the effects of exposure for 3 h at the applied stress before the solution was introduced to the cell, upon the failure of a magnesium alloy immersed in a chromate-chloride solution. Clearly such prior creep extends the lifetime of specimens and raises the threshold stress very considerably and since other metals are known to be strain-rate sensitive in their cracking response, it is likely that the type of result apparent in Fig. 8.100 is more widely applicable. 

Some examples of the type of results expected when using an Orsat apparatus are shown below. 

Three types of results have been obtained and may be summarized as follows. 

Absorbance Reading [AU] Tablet Weight [mg] Assay [mg] Calibration Factor Type of Result... 

Results of parameter optimization and MD simulations of small model compounds have been published, including alcohols [63], alkanes [63], aromatic [64] and heteroaromatic [209] compounds and liquid amides [65], Studies of ions in aqueous solution were also performed [61, 88] and results from an MD simulation on a DPPC lipid monolayer have been reported (Harder, MacKerell, Roux, submitted). Notable from the monolayer study was the reproduction of the dipole potential across the monolayer, a value that cannot be reproduced using non-polarizable models. This exciting, unforeseen observation points to the types of results that may be obtained from polarizable macromolecular force fields that are not accessible to the present additive models. 

Raff I remember Harris Hartenstein (1991) did an experiment in which they used hydroxyurea to block cell proliferation in the Nenopus retina. They showed that all the different cell types still developed. This same type of result has been seen in other systems. 

However, that toluene was not needed. The same type of results, only with a faster rate, have been obtained with an absolute EtOH solvent. 

Water, methanol, and n-hexane do not influence the photooxidation of PVC (43), but the photodegradation is accelerated by ferric chloride (70,71) and certain other compounds containing iron (70,71,72). Purification of the polymer might be expected to enhance its photostability by removing deleterious impurities such as iron compounds that are derived from metal equipment. This type of result was obtained in one recent study (58) but not in others (30,59). In contrast, the photo-oxidative degradation of PVC should be enhanced by admixture of the polymer with materials that are unusually susceptible to photooxidation themselves. Such behavior has been observed for impact-modified PVC containing polybutadiene-based polyblends (69,73). 

The types of results that will be achieved are shown in Figures 13.6 and 13.7. 

Figure 9.4 shows the type of results attained by this procedure. 

The trends presented in Figs. 31 and 32 qualitatively similar to those presented earlier by Agrawal et al. (2001) and Andrews et al. (2005) who, for the sake of simplicity, did simulations on much smaller domains and let the filter size be the same as the domain size. This shows clearly that the effects leading to the type of results presented in Figs. 31 and 32 are robust. 

Two types of results are obtained from mechanical sensitivity tests (1) no reaction, or (2) decomposition with or without an explosion. The magnitude of friction and the impact sensitivity reported is the smallest load at which a positive result has been noted. The objective of mechanical sensitivity testing is to establish whether or not the substance is sensitive under normal handling conditions. However, this objective may not be reached. The test results may not truly reflect process conditions because most testing is carried out at ambient temperature and pressure. Since results are dependent on the type of test apparatus used, the interpretation of the results for use in practical applications requires much experience in this field of testing. 

Table 2 Adequacy between measurement needs and types of results...

To a limited extent, the type of results reported here could be obtained with a TEM instrument fitted with a STEM adapter, especially if a field-emission gun is used (10). We will refer here, however, only to the use of dedicated STEM instruments such as the HB5 or HB501 made by VG Microscopes Ltd. having a cold field emission gun. Most of the instruments of this type are specialized for microanalysis using EDS or ELS and some have been applied very effectively for compositional analysis and associated studies on catalyst particles, as reported elsewhere in this volume. 

Because of this type of result and the thermodynamic expression... 

Unlike premixed flames, which have a very narrow reaction zone, diffusion flames have a wider region over which the composition changes and chemical reactions can take place. Obviously, these changes are principally due to some interdiffusion of reactants and products. Hottel and Hawthorne [5] were the first to make detailed measurements of species distributions in a concentric laminar H2-air diffusion flame. Fig. 6.5 shows the type of results they obtained for a radial distribution at a height corresponding to a cross-section of the overventilated flame depicted in Fig. 6.2. Smyth et al. [2] made very detailed and accurate measurements of temperature and species variation across a Wolfhard-Parker burner in which methane was the fuel. Their results are shown in Figs. 6.6 and 6.7. 

Since this type of result shows that sonication is definitely not just another method of providing agitation of a medium, but exhibits its own peculiarities, it stands to reason that it should obey some rules of its own. An examination and classification of published material led to an empirical systemisation of sonochemistry [28, 30). This classification concentrates on the chemical effects in sonochemistry but it should also be recognised that in some cases ultrasound does act in a mechanical sense achieving remarkable results through super agitation. Sometimes the mechanical and chemical effects occur together. 

There are several large impediments to achieving the goal of more accurate risk assessments. First, it often requires a considerable investment in the research necessary to uncover the types of information needed to replace default assumptions in specific cases. If one hypothesizes that di-(2-ethylhexyl)phthalate (DEHP, a real and important chemical) produces liver tumors in rodents by mechanisms that either do not apply to humans at all, or that do not operate at low (human) doses, or both, then there arises the question of what type of research information is necessary to test the validity of such hypotheses If such research is actually carried out, then what type of results from that research would allow conclusions to be drawn about the validity of the hypotheses In many specific cases creative and knowledgeable scientists can hypothesize alternatives to the usual defaults and ways to test their validity. But it often turns out to be difficult to arrive at... 

Figures 1 and 2 show examples of the types of results obtained. In the spot test (Fig. 1), a small amount of the chemical to be tested is placed in the center of the dish, the chemical diffused out into the agar, and revertant colonies appear as a cloud around the central spot. This method is somewhat limited in sensitivity(3) but is extremely rapid. Normally, one tests individual dose levels of a chemical in the more sensitive plate test, and quantitative dose-response curves can be generated as shown in Figure 2. The initial portion of these curves is almost always linear, and most mutagens are detected at nanogram dose levels.

The evaluation methodology depends on demand of results Are only Yes/No answers needed or semiquantitive statements ( strong - medium - weak ), or are reliable values necessary To get the first two types of results you have only to choose the right assay protocol and measuring range. For quantitative evaluations often more points of view have to be considered, e.g., rules of statistics. (Some statistic parameters are given in Chap. 9.)... 

Both types of dynamics calculations gave the same type of results. The calculations found that the ratio of double-to-single methylene rotations is higher than the 1 1 ratio predicted by application of a TST model to the PES. Ratios of double-to-single rotations between 2.9 and 3.5 were obtained from the direct dynamics calculations of Doubleday et al., and a ratio of 4.7 was computed from the trajectory calculations performed by Carpenter and co-workers. ... 

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