Physical Rationale

For kinetic disequilibrium partitioning of trace elements, equation (9.6.6) after Burton et al. (1953) is commonly presented as an alternative to equation (9.6.5) due to Tiller et al. (1953) (e.g., Magaritz and Hofmann, 1978 Lasaga, 1981 Walker and Agee, 1989 Shimizu, 1981). However, the relative values of viscosity and chemical diffusivity in common liquids and silicate melts make the momentum boundary-layer (i.e., the liquid film which sticks to the solid) orders of magnitude thicker than the chemical boundary layer. It is therefore quite unlikely that, except for rare cases of transient state, liquid from outside the momentum boundary-layer may encroach on the chemical boundary-layer, i.e., <5 may actually be taken as infinite. As a simple description of steady-state disequilibrium fractionation, the model of Tiller et al. (1953) has a much better physical rationale. A more elaborate discussion of these processes may be found in Tiller (1991a, b). 

There are two predictive relationships based on wind speed. Liss and Merlivat (1986) used a physical rationale to explain the increase in the Kl versus wind speed slope at higher wind velocities in wind-wave tunnel and lake measurements, resulting in a piecewise linear relationship with two breaks in slope. These breaks are presumed to occur at the transition between a smooth surface and a rough surface and between a rough surface and breaking waves. In dimensionless form, this relationship is given as... 

RANDOM PROCESSES, VARIANCE, AND DIFFUSION 93 A physical rationale for this particular dependence [8] is summarized below. 

In Section 2,1 will discuss the observational evidence of climate change. As a suitable point of reference in my review, I will use the recent attempts by Mann et al, (1998, 1999) to reconstruct the surface temperature of the Northern Hemisphere for the last millennium. In Section 3, I will address the physical rationale underpinning climate change modeling, and finally in Sections 4 and 5,... 

In his study of metal-ion toxicity to aquatic biota, Kaiser (1980) provided a physical rationale, based on electronic configuration, for classifying metal ions into three groups. With respect to the outer electron shells, his groups consist of (1) ions with completely filled p orbitals, such as Ba(ll) and Al(lll) (2) ions with partly or completely filled d orbitals, such as Ag(l), Co(ll), and Fe(lll) and (3) ions with filled s orbitals, such as Pb(ll) and As(lll). Kaiser used an equation of the following form to fit the toxicity data for each group ... 

CESR D Factory Physics Rationale for a D-Factory, CLNS 91-1043 (1991). 

Svaasand, L.O., Corner, C.J. and Morinelli, E. (1990) On the physical rationale of laser induced hyperthermia. Lasers in Medical Science, 5,121-8. 

Explains the rationale for increasing fluid intake to at least 2000 mL/d (unless contraindicated) to aid in physical removal of bacteria... 

The first two chapters serve as an introduction to quantum theory. It is assumed that the student has already been exposed to elementary quantum mechanics and to the historical events that led to its development in an undergraduate physical chemistry course or in a course on atomic physics. Accordingly, the historical development of quantum theory is not covered. To serve as a rationale for the postulates of quantum theory, Chapter 1 discusses wave motion and wave packets and then relates particle motion to wave motion. In Chapter 2 the time-dependent and time-independent Schrodinger equations are introduced along with a discussion of wave functions for particles in a potential field. Some instructors may wish to omit the first or both of these chapters or to present abbreviated versions. 

Additional guidance on the development pharmaceutics aspects of this type of product is included in document CPMP/QWP/604/96, adopted July 1999. This emphasizes the need for information on the rationale for the design of the product—e.g., therapeutic benefit, pharmacokinetics, and physical properties of the active ingredient. 

The application should state the rationale for the design of the in-use stability tests performed. The procedures used should be fully validated. One key factor is that the test should simulate the use of the product as far as practicable. This should include any reconstitution or dilution prior to use. Aliquots should be removed in an appropriate manner following, as far as possible, the usage pattern that will be encountered in practice. Physical (color, clarity, closure integrity, particulate matter, and particulates/particle size), chemical (assays for active ingredient, antioxidants and... 

Attempts to account for this bending have emphasized two physical effects, (1) d-orbital participation,18 and (2) core polarization,19 but no clear theoretical consensus has been achieved. The calculated bending in BaH2, for example, is found to disappear with removal of either d-orbitals or a polarizable-core, suggesting that both aspects are operative. The adequacy of the core-polarization rationale was questioned, and an alternative rationalization based on differences in atomic softness between metal and ligand was proposed by Szentpaly and Schwerdtfeger.20... 

For many chemical reactions with high sharp barriers, the required time dependent friction on the reactive coordinate can be usefully approximated as the tcf of the force with the reacting solute fixed at the transition state. That is to say, no motion of the reactive solute is permitted in the evaluation of (2.3). This restriction has its rationale in the physical idea [1,2] that recrossing trajectories which influence the rate and the transmission coefficient occur on a quite short time scale. The results of many MD simulations for a very wide variety of different reaction types [3-12] show that this condition is satisfied it can be valid even where it is most suspect, i.e., for low barrier reactions of the ion pair interconversion class [6],... 

This simple valence-bond rationale, involving a resonance hybrid of forms 1 and 2, appears to explain many of the physical data available for sulfoxide complexes. It appears that S-bonding does not involve such a major internal rearrangement of the molecule as one may initially expect and is almost certainly a result of the increased orbital diffuseness on passing from oxygen to sulfur. Thus with typical hard acids (see ref. 437), orbital overlap will be most favorable with the less diffuse donor orbital of oxygen. In the case of typical soft metals, this overlap is less favorable due to the orbital diffuseness of the soft acid, and so coordination via sulfur occurs, where the orbital diffuseness of the donor and acceptor are more evenly matched. 

Barton and Buffum proposed to an enraged Bancroft that he turn over his faltering journal to the AIP as a forum for mathematically oriented papers at the "borderland" of physics and chemistry. When he refused, the Chemical Foundation switched its financial support from the Journal of Physical Chemistry to the proposed AIP journal. Karl Compton, president of MIT and chairman of the governing board of the AIP, requested Lewis and others to serve on the advisory board for the journal that Harold Urey would edit. Compton s letter carried this statement defining the rationale for establishing the journal ... 

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