Temporary local environment

It is noteworthy that the neutron work in the merging region, which demonstrated the statistical independence of a- and j8-relaxations, also opened a new approach for a better understanding of results from dielectric spectroscopy on polymers. For the dielectric response such an approach was in fact proposed by G. Wilhams a long time ago [200] and only recently has been quantitatively tested [133,201-203]. As for the density fluctuations that are seen by the neutrons, it is assumed that the polarization is partially relaxed via local motions, which conform to the jS-relaxation. While the dipoles are participating in these motions, they are surrounded by temporary local environments. The decaying from these local environments is what we call the a-process. This causes the subsequent total relaxation of the polarization. Note that as the atoms in the density fluctuations, all dipoles participate at the same time in both relaxation processes. An important success of this attempt was its application to PB dielectric results [133] allowing the isolation of the a-relaxation contribution from that of the j0-processes in the dielectric response. Only in this way could the universality of the a-process be proven for dielectric results - the deduced temperature dependence of the timescale for the a-relaxation follows that observed for the structural relaxation (dynamic structure factor at Q ax) and also for the timescale associated with the viscosity (see Fig. 4.8). This feature remains masked if one identifies the main peak of the dielectric susceptibility with the a-relaxation. 

A simple phenomenological theory has been given (4-7) which appears to rationalize all the experimental observations for the a, B and (aB) dielectric relaxations in amorphous solid polymers. It is assumed that a reference dipolar group in the polymer system may partially reorientate via motions in a temporary local environment (B process) but at sufficiently long times may completely reorientate by cooperative rearrangements of that local environment (a process). When the time scales of the two processes are sufficiently different, i.e. for T < Tg or for T just above Tg, the dipole moment vector correlation function may be written as (4-6)... 

We assume that a representative dipole k may find itself in a ivide variety of temporary local environments at the arbitrary time t = 0. It is assumed that as time develops the dipole is partially relaxed via the local motions in a particular environment r(k) say (i.e. for dipole k) and is characterized by a relaxation function V>(3r(k) (0 The dipole is subsequently totally relaxed by an a-ptocess which involves the collapse of the local environment, and is characterized by a relaxation function [Pg.70]

In situ STM of metalloproteins with localized low-lying redox levels can be expected to follow ET patterns similar to metalloprotein ET in homogeneous solution and at electrochemical surfaces. The redox level is thus strongly coupled to the protein and solvent environment. A key notion is that the vacant local level (oxidized form) at equilibrium with the environmental nuclear motion is located well above the Fermi levels of both the substrate and tip, whereas, the occupied level (reduced form) at equilibrium is located well below the Fermi levels. Another central notion is that the local redox level at the transition metal centre is still much lower than environmental protein or solvent electronic levels. The redox level therefore constitutes a pronounced indentation in the tunnel barrier. This alone would strongly enhance tunnelling. Configurational fluctuations in the environment can, secondly take the redox level to such low values that temporary physical population occurs. This requires nuclear activation but can still be favourable due to the much shorter electron tunnel distances... 

During normal battery usage, there is no reason to expect the battery contents to leave the batteries and enter the environment in an uncontrolled manner. Accidents do occur, however, due to inadvertent or deliberate abuse, or due to battery damage caused by other events such as collisions or fires. Occurrences of this kind may generate excessive local concentrations of toxic or harmful substances or other hazards, such as acid or alkali burns, toxic vapors, or explosions, with undesirable effects on nearby persons or on the local enviromnent. Apart from the local and temporary effects, events of this kind are rare and do not significantly contribute to environmental contamination in general. 

What can be presently said about the contribution of automobile exhaust to the general PAH pollution in our environment This question certainly can not be answered as it has been tried in the introduction of this paper, calculating the benzo(a)pyrene concentration from automobile exhaust profiles and fuel consumption, since temporary and local variations have to be taken into account. In 196 a concentration of l60 ng benzo(a)pyrene/m was measured in the Essen area of Northrhine-Westphalia (FRG) (l4), whereas nowadays the mean concentration there varies between 1.2-27 ng/m- ... 

Our study focuses on selecting location of temporary warehouses (local distribution centers) at post-disaster for facilitating an efficient and effective response operation and determining amount of relief supplies that will be delivered through the relief network in order to minimize cost as well as maximize customer satisfaction under uncertainly environment. The proposed relief network encompasses three tiers multi-collection centers, candidates of local distribution centers (LDCs), and demand points. It should be noted that the majority of papers address to historical information to select the distribution center locations. Our model is applied for designing relief plaiming based on the future disaster predicted by scientist and agreed by disaster stockholders. 

The sum of frequencies of all event sequences that can lead to a release to the environment of more than 10 becquerel of iodine-131 is less than 10 per reactor year. A greater release may require temporary evacuation of the local population. 

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