Concept phase

In order to show the versatility of the method Davis extended the concept to other hydrophilic liquids such as ethylene glycol and glycerol [70], The reactions then take place at the hydrophilic-hydrophobic liquid interface. In this specific example the supported-phase concept was used for asymmetric reduction using a ruthenium catalyst. 

Reflecting the increasing importance of drug transporters in pharmacokinetics, we need to extend the historical two-phase concept for the metabolism of xenobiotics. As shown in Figure 15.1, the metabolic phases I (oxidation) and II (conjugation) are flanked by drug transporter phases 0 (uptake) and III (export). Phase 0 is the first step... 

Figure 15.1 Schematic illustration of the extended phase concept during drug elimination in the kidney and liver. Phase 0 = uptake of drugs from the blood into the hepatocytes or proximal tubule epithelial cells. This uptake is mediated by transport proteins belonging to the SLC (solute carrier) transporter superfamily. Phase I and...

One of the dominant issues in coal structure to re-emerge in the past decade is the two-phase concept of coal structure. A very spirited discussion of this topic was a feature of the 1989 symposium (48-52V Peter Given played a central role in the recent work on the two-phase concept, particularly in fostering the usage of the terms "mobile phase" and "macromolecular network" (23.53-551 and in organizing the "debate in print" (54V which has become a landmark papers in coal structure. In particular, the debate in print (24) was cited by all of die contributors to the 1989 discussion of the mobile phase (48-52V Given s work on the mobile phase was a... 

The dielectric relaxation of bulk mixtures of poly(2jS-di-methylphenylene oxide) and atactic polystyrene has been measured as a function of sample composition, frequency, and temperature. The results are compared with earlier dynamic mechanical and (differential scanning) calorimetric studies of the same samples. It is concluded that the polymers are miscible but probably not at a segmental level. A detailed analysis suggests that the particular samples investigated may be considered in terms of a continuous phase-dispersed phase concept, in which the former is a PS-rich and the latter a PPO-rich material, except for the sample containing 75% PPO-25% PS in which the converse is postulated. 

In view of this phase concept which is confirmed by the micellization phenomena in many nonpolar detergent solutions, it has been suggested by Eicke and Christen40 that in line with this reasoning a nucleation step is to be expected (in the approximation of the phase separation model). In order to explain the origin of the energy necessary to overcome the potential barrier associated with the postulated... 

The deposition of unstable amorphous precursor phases requires a hydrated medium that has a very high ion concentration, and an inordinately high supersaturation relative to the corresponding crystalline phases. In order to stabilize, even transiently, such high supersaturations, specialized inhibitors of crystallization probably need to be present. Such high concentrations of ions cannot be regarded as a solution, but rather a structured colloidal phase. Concepts such as mechanisms of diffusion, levels of supersaturation and consequently kinetics of crystallization, must be reconsidered if crystallization does not occur from free solution. 

A structural dilemma lies in combining a phase concept of the molecular arrangement with the molecular description of the contraction process. It is known that the movements of different myosin heads on a particular myosin thread occur asynchronously, which is evident for example, from X-ray diffraction experiments. That means that a force is generated constantly with time. The coordination of movement between every muscle cell (down to the individual actin/myosin molecule) is controlled by the excitation via the tubuli system, which is a cubosome type of membrane system, described in the previous chapter. 

Because the primary octadienylamines react faster than ammonia itself, the main products of this homogeneous reaction are the secondary and tertiary octadienylamines. By application of the two-phase concept, primary octadienylamines became the main products [5]. Table 1 shows the remarkable difference between the homogeneous and the two-phase reaction. 

A novel design route expanding on such a two-phase concept has already been followed by the company 3M for some time. The benefits in terms of catalyst utilization and performance enhancement are evident from that work [147]. The activity per total mass of Pt of the 3M layers is larger by about a factor 6 than the mass activity of conventional three-phase CCLs. This affirms the awful inactivity of Pt in conventional CCLs. 

There are several concepts for the description of phase in quantum theory at present. Some of them are accenting the theoretical aspects, other the experimental ones. Quantization based on the correspondence principle leads to the formulation of operational quantum phase concepts. For example, the well-known operational approach formulated by Noh et al. [63,64] is motivated by the correspondence principle in classical wave theory. Further generalization may be given in the framework of quantum estimation theory. The prediction may be improved using the maximum-likelihood estimation. The optimization of phase inference will be pursued in the following. 

First, let us show that the operational phase concepts can naturally be embedded in the general scheme of quantum estimation theory [66,67] as was done by Hradil, Zawisky, and others [68-71]. Let us consider the eight port homodyne detection scheme [63,72] with four output channels numbered by indices 3,4,5,6, where the actual values of intensities are registered in each run. Assume that these values fluctuate in accordance with some statistics. The mean intensities are modulated by a phase parameter 0... 

One focus of the book is the hydroformylation process, the process involved in the first commercial implementation of aqueous-phase catalysis with its detailed descriptions of fundamental laws, special process features, and the present state of the art. Further focal points of the book are basic research on the complex catalysts (central atoms, ligands) and on the influence of the reaction conditions, solvents, and co-solvents, and a survey of other aqueous two-phase concepts and of proposed applications, with experimental examples and details. Environmental aspects are also considered. 

These types of studies are yet another example of how gas phase concepts can be profitably brought into the discussion of solution phase reactions. In the systems studied by Benjamin et al., it is possible to correlate the necessity of having a particular orientation and the dynamics that cause that orientation to arise with the nature of the potential energy surface and the reactant—solvent interaction. 

Commercially, the aqueous-phase concept was firstly applied in Ruhrchemie/Rhone-Poulenc s (RCH/RP) process (for the fundamentals, see Section 2.4.1.1). In several units the RCH/RP process has been converting propene to n-butyraldehyde and isobutyraldehyde (or butenes to valeraldehydes) since 1984 in the presence of HRh(CO)(TPPTS)3 (with TPPTS = m-trisulfonated triphenylphosphine or tris-(sodium-fn-sulfonatophenyl)phosphine as water-soluble ligand) according to Eq. (1). The output of the units mentioned is approximately890 000 tpy, which corresponds to roughly 13% of the world s total production. 

The phase concept does not imply that there is a rigid sequence in the development process, as in the waterfall model. Rather, the phase concept also includes an evolutionary prototyping procedure. However, even in evolutionary software development, the following description levels are generally used. Phase models are primarily used because they offer a variety of description objects and methods. 

CIMOSA distinguishes three different dimensions, described by the three axes of the cube. The vertical direction (stepwise derivation) describes the three description levels of the phase concept ... 

For a better understanding of the plaiming systematics, the phase concept planning will be represented and explained using the example of a factory producing pumps (Wiendahl et al. 2009). 

However, it is to be noted, that the one-phase concept need not apply to all solid polymer substances. In cellulose no measurable influence of stretch on crystallinity is observed let alone a reversible one. It is quite possible that the attainment... 

If, for example, the separated colloid-rich phase remains for some reason or other in a very highly dispersed state of division, then systems can be produced which are macroscopically and microscopically homogeneous. Two types of these systems are known, of which the one has throughout the nature of a liquid, the other that of a solid body. They can be called " apparent single colloid systems, (compare p. 7 Ch. I 3d). This nomenclature indicates that it is appropriate for various reasons to treat them as two-phase systems. In this respect they differ from the true ""single colloid systems (the original sols, the colloid crystals, the coacervates), in which the one-phase conception is the more appropriate. 

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