Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Variations and refinements

There are several variations and refinements possible that might, depending on the [Pg.172]

Process cheap tests first, i.e. tests consuming the least computation time. Process selective tests first, i.e. tests eliminating the most intermediates. [Pg.172]

Tests that fulfill both criteria should be processed first, while those that fulfill none of them should be executed last. However, one has to find a trade-off for expensive tests that are very selective and cheap tests with low selectivity. [Pg.173]


It is worthwhile to describe how the heat of a reaction is calculated from the quantities that are actually measured in a calorimetric experiment. It is not possible in a brief space to describe all the types of calorimeters or all of the variations and refinements of technique that are necessary in individual cases and in precision work. A highly idealized situation will be described to illustrate the methods involved. [Pg.143]

The driving state is normally continually monitored (by the driver and/or a system) in order to make corrections on any or all of these levels if required. Detailed applications, variations and refinements of this model can be found in the literature [4, 10-12]. Classically, active safety systems, e.g.. Dynamic Stability Control (DSC), have been designed to provide support at the stabilization level. At this level, the target quantities are generally well defined in terms of vehicle physics. Preventive pedestrian protection, which is in the focus of this thesis, addresses primarily the maneuvering level and thus involves additional eomplexities in control—particularly those involving the interpretation of driver behavior and the interaction of system actions with the driver. [Pg.3]

Sequence, Information, and Genes Codon Information to a Protein DNA Replication mRNA Dynamics Variations and Refinements of the Central Dogma... [Pg.40]

A detailed treatment of the various theories of adhesion is beyond the scope of this paper. However, Table I below summarizes the various contributions by type, author and year up to about 1970. During the last decade or so, variations and refinements of these theories have appeared, and it is interesting to note that the basic molecular-kinetic stick-slip explanation of the adhesional mechanism remains intact. [Pg.415]

Section 4.1 provides an overview of the design of object collaborations. Section 4.2 begins with examples of object interactions to show that many variations in interaction protocols achieve the same net effect and so motivate the need for abstract actions. Section 4.3 introduces use cases and relates them to actions and refinement. Section 4.4 explains how actions and effects are related to abstract actions. Section 4.5 describes concurrency between actions and explains how to specify these constraints. [Pg.179]

A common probe of reaction mechanisms used to infer charge distribution in the transition state involves variation of substituent groups near the reaction center. From the variation in reaction rate produced by electron-donating and electron-withdrawing groups or by the steric hindrance of various sized groups, transition state characteristics can be inferred. Two empirical correlations have been proposed and refined which provide a common framework for this process. The Hammett equation is applied to aromatic systems [45]. The Taft correlation is applied to aliphatic systems [45], Definitions of terms, collections of substituent constants (steric and electronic effects for various substituents), and listings of observed reaction response parameters (for typical reaction types) have been collected [45]. [Pg.123]

The parameters needed to describe such a model are, for each discrete interaction, the distance, its rms variation and the frequency, and corresponding parameters for describing the emergence of the continuum. The parameter values can be refined either in s space by a least squares procedure minimizing... [Pg.168]

Many modifications and refinements were proposed to improve the utility of this equation for different situations. Golay3 showed that the A term was not needed for open tubular columns in GC, and Giddings4 proposed a complicated coupled term in his extensive treatment of the theory. Huber5 and others noted that a fourth term was necessary for LC to account for mass transfer in the liquid mobile phase. The exact terms in these variations of the rate theory are given in Table 1 mainly for their historical value. [Pg.171]

Lecithin, both natural and refined grades, occurs as a substance varying in consistency from plastic to fluid depending on free fatty acid and oil content and on the presence or absence of other diluents. Its color varies from light yellow to brown, depending on the source, on crop variations, and on whether it is bleached or unbleached. Lecithin is obtained from soybeans and other plant sources. [Pg.248]

Optionally the x, exponents can be re-optimized too. However, this integer optimization seems very insensitive to the addition of new functions. The best strategy consists in testing if some possible variation of the exponents as well as the attached exponential scale factors optimizes the overlap once all the exponential scale factors had been previously set and refined. ... [Pg.184]

A total of 1463 raw intensity data were collected. Inspection of the azimuthal scan data showed a variation of /mia//max = 0.82 for the average curve. An empirical correction based on the observed variation was applied to the data as a first approximation. The structure was solved by Patterson methods in space group P. Refinement and elucidation of additional atoms proceeded via standard least-squares and Fourier techniques. Examination of the triclinic model demonstrated the correct monoclinic space group, P2Jc (the apparent absence of hOl, l 2n has been found), and refinement continued in (hat group... [Pg.475]

Clearly, operations of different size, and lacking some processes, will have different waste loads. This applies particularly to acidulation as well as mayonnaise and salad dressing processing. In addition, variations in refining process methods will greatly impact wastewater characteristics. This is addressed in more detail in Section 7. The effects of process control and its impact on wastewater loading are outlined in the next section. The values in Table 1 can be adjusted for different processing sizes however, this adjustment should be done with caution and not... [Pg.2391]

Historically, the chemical selection process has been performed on a bench-top scale. Bottle tests (including ratio, elimination, and confirmation test), jar tests, and portable electric desalter tests fall into this test category. No effort will be made to describe these tests or the associated analytical procedures in detail, as they are described in Chapters 3 and 10. Furthermore, significant variation in testing procedures will exist between various chemical companies, oil producers, and refiners. Each test procedure is also tailored to each treating facility. [Pg.335]

There is an emerging body of evidence that suggests person-to-person differences in exposure play an important role in the variability and uncertainty associated with risk assessments for chemicals (and other agents). The traditional or standard default approaches used in human health risk assessment often do not effectively evaluate interindividual variation and may underestimate the impact of chemical exposures on particular groups of individuals. Traditional approaches must be refined to adequately account for temporal variation in factors that contribute to complex aggregate exposure patterns (e.g., chemical-specific exposure media concentrations and time-activity interactions by humans) involving multiple, intermittent exposures. [Pg.57]


See other pages where Variations and refinements is mentioned: [Pg.405]    [Pg.44]    [Pg.172]    [Pg.33]    [Pg.1062]    [Pg.88]    [Pg.47]    [Pg.405]    [Pg.44]    [Pg.172]    [Pg.33]    [Pg.1062]    [Pg.88]    [Pg.47]    [Pg.141]    [Pg.1012]    [Pg.233]    [Pg.218]    [Pg.8]    [Pg.303]    [Pg.304]    [Pg.341]    [Pg.73]    [Pg.68]    [Pg.4]    [Pg.32]    [Pg.141]    [Pg.160]    [Pg.17]    [Pg.260]    [Pg.309]    [Pg.302]    [Pg.885]    [Pg.259]    [Pg.368]    [Pg.4321]    [Pg.5030]    [Pg.122]    [Pg.281]    [Pg.965]    [Pg.244]   


SEARCH



© 2024 chempedia.info