Dynamic parameter

As already discussed above chlorine, bromine and iodine nuclei all have I 1 and possess large electric quadrupole moments. It is therefore not surprising that in a majority of systems studied by NMR the dominant relaxation mechanism is due to quadrupolar interactions. The only exceptions encountered so far concern certain paramagnetic systems. 

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The often-cited Amontons law [101. 102] describes friction in tenns of a friction coefiBcient, which is, a priori, a material constant, independent of contact area or dynamic parameters, such as sliding velocity, temperature or load. We know today that all of these parameters can have a significant influence on the magnitude of the measured friction force, especially in thin-film and boundary-lubricated systems. 

In a different field, location, and characteristics of ci s on diabatic potential surfaces have been recognized as essential for the evaluation of dynamic parameters, like non-adiabatic coupling terms, needed for the dynamic and... 

Spray characteristics are those fluid dynamic parameters that can be observed or measured during Hquid breakup and dispersal. They are used to identify and quantify the features of sprays for the purpose of evaluating atomizer and system performance, for estabHshing practical correlations, and for verifying computer model predictions. Spray characteristics provide information that is of value in understanding the fundamental physical laws that govern Hquid atomization. 

The model is able to predict the influence of mixing on particle properties and kinetic rates on different scales for a continuously operated reactor and a semibatch reactor with different types of impellers and under a wide range of operational conditions. From laboratory-scale experiments, the precipitation kinetics for nucleation, growth, agglomeration and disruption have to be determined (Zauner and Jones, 2000a). The fluid dynamic parameters, i.e. the local specific energy dissipation around the feed point, can be obtained either from CFD or from FDA measurements. In the compartmental SFM, the population balance is solved and the particle properties of the final product are predicted. As the model contains only physical and no phenomenological parameters, it can be used for scale-up. 

DYNAMIC PARAMETERS FOR CHARACTERIZATION OF HETEROGENEOUS SYSTEMS AVAILABLE FROM SOLUTION AND SOLID-STATE NMR... 

Dynamic parameters for heterogeneous systems have been explored in the liquid, liquid like, solid like, and solid states, based on analyses of the longitudinal or transverse relaxation times, chemical exchange based on line-shape analysis and separated local field (SLF), time domain 1H NMR, etc., as summarized in Figure 3. It is therefore possible to utilize these most appropriate dynamic parameters, to explore the dynamic features of our concern, depending upon the systems we study. 

Detailed theories include all these effects in the reaction cross-section, which is then a function of all the various dynamic parameters ... 

Additional limitations in the accuracy of the derived dynamic parameters could be related to the limitations in the analytical approaches. For example, neglect of the overall rotational anisotropy could lead to considerable errors in the model-free parameters, as illustrated earlier [46]. As also shown in Ref. [6], the model-free parameters could be in error if the site-specific variations in 15N CSA are not properly taken into account, particularly at higher fields (>600 MHz 111 frequency). 

Calculation of the dynamic parameters using a ZND wave structure model do not agree with experimental measurements, mainly because the ZND structure is unstable and is never observed experimentally except under transient conditions. This disagreement is not surprising, as numerous experimental observations show that all self-sustained detonations have a three-dimensional cell structure that comes about because reacting blast wavelets collide with each other to form a series of waves which transverse to the direction of propagation. Currently, there are no suitable theories that define this three-dimensional cell structure. 

An excellent description of the cellular detonation front, its relation to chemical rates and their effect on the dynamic parameters, has been given by Lee [6], With permission, from the Annual Review of Fluid Mechanics, Volume 16, 1984 by Annual Reviews Inc., this description is reproduced almost verbatim here. 

The extent to which a detonation will propagate from one experimental configuration into another determines the dynamic parameter called critical tube diameter. It has been found that if a planar detonation wave propagating in a circular tube emerges suddenly into an unconfined volume containing the same mixture, the planar wave will transform into a spherical wave if the tube diameter d exceeds a certain critical value dc (i.e., d > dc). II d < d.. the expansion waves will decouple the reaction zone from the shock, and a spherical deflagration wave results [6],... 

These studies showed that sulfonate groups surrounding the hydronium ion at low X sterically hinder the hydration of fhe hydronium ion. The interfacial structure of sulfonafe pendanfs in fhe membrane was studied by analyzing structural and dynamical parameters such as density of the hydrated polymer radial distribution functions of wafer, ionomers, and protons water coordination numbers of side chains and diffusion coefficients of water and protons. The diffusion coefficienf of wafer agreed well with experimental data for hydronium ions, fhe diffusion coefficienf was found to be 6-10 times smaller than the value for bulk wafer. 

II. From the NMRD profile to the structural and dynamic parameters 140... 

II. From the NMRD Profile to the Structural and Dynamic Parameters... 

As far as Gd(III) agents are concerned, several systems have so far been investigated (mostly in vitro). The design of a Gd(III)-based complex whose relaxivity is pH-dependent requires that at least one of the structural or dynamic parameters determining its relaxivity is rendered pH-dependent. In most of the examples so far reported, the pH-dependence of the relaxivity reflects changes in the hydration of the metal complex. 

In principle, the relaxivity of almost all Gd(III) complexes is affected by temperature as a result of the temperature dependence of the dynamic parameters controlling r, namely t/j, tm, and D. Nevertheless, the effect of temperature on the relaxivity is usually rather small and, therefore, of little utility for clinical use. 

In cases where dynamic effects must be considered, the problem is typified by A and b matrices that are parametrized, say, by time or other quantities. One such example involves modeling corrosion effects where time, acidity, and material thickness and age might be relevant dynamical parameters. In most cases one calculates a sequence of static solutions at time steps t that are then pieced together to fit initial (and final) conditions. 

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