The Effects of Motions

Of course, all multi-atomic species are actively vibrating, usually at frequencies much higher than those of nuclear magnetic effects. Thus NMR generally measures parameters time-averaged over vibrations. We shall not deal with this aspect herein. 

Single-crystal EPR and NMR measurements involve spectral measurement at fixed orientations relative to the applied magnetic field B, and rotating the crystal (about some selected axis by set angles) between such measurements. Then road maps can be constructed of line positions (or intensities) versus the positional 

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In electrolyte solutions the positively and negatively charged ions will move in opposite directions when an electric field is applied. Therefore, outwardly the effect of motion of positive ions is exactly the same as that of the motion of negative ions, and the total current density is the sum of the partial currents due to hansport of each type of ion ... 

In addition to the effects of motional narrowing, vibrational line shapes for the OH stretch region of water are complicated by intramolecular and intermolecular vibrational coupling. This is because (in a zeroth-order local-mode picture) all OH stretch transition frequencies in the liquid are degenerate, and so the effects of any... 

Herein we present calculations [6] for liquid H20 that are similar in spirit but different in detail from those of Buch [71, 110] and Torii [97]. The MD simulations are of the SPC/E model [135]. Local-mode anharmonic frequencies are generated from our most recent map developed for the H0D/D20 system [98], as are our transition dipoles. The relatively small intramolecular coupling fluctuates with molecular environment, and is determined by a separate map parameterized from ab initio calculations on clusters. The form of the intermolecular couplings is transition dipole, which is tested and parameterized from additional ab initio calculations. The effects of motional narrowing are taken into account approximately with the TAA [99]. 

When we say force is the cause of motion we talk metaphysics, and this definition, if we were content with it, would he absolutely sterile. For a definition to be of any use, it must teach us to measure force. Moreover that suffices it is not at all necessary that it teach what force is in itself nor whether it is the cause or the effect of motion. 

The symmetries of molecules usually change during the vibrations, mostly their symmetries become lower (Figure 2), sometimes they don t change, and in some special cases they may become higher. In most of our discussion, the effects of motion on molecular symmetry will be ignored for... 

In passing it is interesting to note that Fig. 5 qualitatively explains the reason for the difference in the effect of motion on spectral lines in radiofrequency and optical spectroscopy. In radiofrequency spectroscopy one refers to motional narrowing, while collisional broadening is used to... 

A. N. Garroway I would still hold out the hope for using these carbon relaxation rates to interpret mechanical properties, but the onus is on the experimenter to show he is actually measuring the effects of motion. Once that is done 1 think the idea will compete as freely as any other scientific concept. 

The floating production system meets these criteria with one exception the motions of the marine vessel can reduce the operating level from that of a fixed structure. A major concern 1s the effect of motions on the performance of the process equipment. Consequently, there 1s a requirement to Increase the operating level by reducing the motions of the marine vessel and reducing the effects of the transmitted motion on the process Inside the vessel. The latter, reducing the effects of the transmitted motion on the process Inside the vessel, 1s the subject of this paper. 

The following example Is Included to show the effects of motion on a 50,000 barrel per day primary separator. Three motion conditions are considered no motion, moderate motion (3 degree of pitch), and substantial motion (6 degree of pitch) - 1t 1s assumed other motions Increase typically with the pitch, the parameters of size and cost are computed assuming the separator 1s part of a process system producing high quality product. 

When the H- H dipole-dipole interaction can be measured for a specific pair of H nuclei, studies of the temperature dependence of both the H NMR line-shape and the H NMR relaxation provide a powerful way of probing the molecular dynamics, even in very low temperature regimes at which the dynamics often exhibit quantum tunnelling behaviour. In such cases, H NMR can be superior to quasielastic neutron scattering experiments in terms of both practicality and resolution. The experimental analysis can be made even more informative by carrying out H NMR measurements on single crystal samples. In principle, studies of both the H NMR lineshape and relaxation properties can be used to derive correlation times (rc) for the motion in practice, however, spin-lattice relaxation time (T measurements are more often used to measure rc as they are sensitive to the effects of motion over considerably wider temperature ranges. 

Dehydration of the small-pore zeolite analcime (NaAlSi20e) has also been studied by high-temperature Na NMR measurements up to 500°C (Kim and Kirkpatrick 1998) in which changes in the Na peak positions and widths with temperature were interpreted in terms of exchange between the Na sites and the effect of motional averaging of the intensity of the ( 1/2, 3/2) satellite transitions. 

Figure 3.2.4 The effect of motion about the molecular symmetry axis, either by two-fold orn-fold (n>3) flips, on the deuterium spectrum of a deuter-ated para-substituted benzene. Reproduced with permission from Ref. [10].

The morphology of a polymer plays an important role in determining its properties, but the molecular motions that take place within the polymer play an equally important role. The later part of this chapter deals with the types of motion that can take place in solid polymers and the evidence for these motions. This topic of motion is taken up again in subsequent chapters, particularly in chapters 7 and 9, where the effects of motion on the mechanical and dielectric properties of solid polymers are discussed. 

In chapter 5 the use of NMR spectroscopy in studying the various kinds of motion that can take place in solid polymers is described and in the present chapter the way that these motions contribute to the time-dependent mechanical properties of the polymers is considered. In chapter 9 the effects of motion on the dielectric properties and the use of measurements of dielectric relaxation in the study of relaxation mechanisms are considered. 

It is convenient to discuss the effect of motion on the intramolecular interactions (where r is constant) separately from the intermolecular interactions where both P and r vary with time. Similar transformations of(3 cos Pjh—l) to those employed in the rigid lattice case, enable us to relate the second moment to the angle 7 between the draw direction and Ho, and cos A and cos A which define the orientation functions for the transversely isotropic situation which has been analysed. We find... 

Hummel et a/. have developed testing apparatns consisting of manikin hands to evaluate protective gloves. Others have focused on posture adjustable manikins to incorporate the effect of motion on garment flammability and/or thermal protection. 

It will be remembered that an adiabatic wall was defined as one which prevents an enclosed body being influenced from beyond, except by the effect of motion. (We are not concerned here with force fields.) Experience shows that when there is motion of the wall, or parts of it, the state of the adiabatically enclosed body can be changed for example by compressing or expanding the enclosing wall, or by shaking the body inside. The first law of thermodynamics is based on a consideration of such processes which involve the performance of work.. ... 

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