Nonuniformities discontinuous

By monolithic we mean having a microstructure that is uniform and continuous and was formed from a single material furthermore, more than one microconstituent may be present. In contrast, the microstructiue of a composite is nonuniform, discontinuous, and multiphase, in the sense that it is a mixture of two or more distinct materials. 

Crystalline polymers undergo a discontinuous decrease in volume when cooled through (Fig. 4). This can lead to nonuniform shrinkage and warping in molded objects. On the other hand, it also causes the polymer to "lock on" to reinforcing fibers, eg, glass (qv), so that crystalline thermoplastics benefit much more than amorphous thermoplastics from fiber reinforcement. 

Insoluble corrosion prodiic ts may be completely impeivious to the corroding liquid and, therefore, completely protective or they may be quite permeable and allow local or general corrosion to proceed unhindered. Films that are nonuniform or discontinuous may tend to localize corrosion in particular areas or to induce accelerated corrosion at certain points by initiating electrolytic effects of the concentration-cell type. Films may tend to retain or absorb moisture and thus, by delaying the time of drying, increase the extent of corrosion resulting from exposure to the atmosphere or to corrosive vapors. 

This property of the degenerate equation of exhibiting a nonuniform convergence of for t 0 means that for the degenerate equation the velocity jumps quasi-discontinuously to its proper value, so that only one constant of integration is sufficient, in spite of the fact that the state of rest is specified by two initial conditions, x0 = x0 = 0. 

A third important characteristic of a female moth s sex-pheromone plume is its nonuniformity. Simulation of odor plumes using ionized air has shown clearly that a plume is not a simple concentration gradient but instead is distinctly filamentous and discontinuous (47,48). Furthermore,... 

The second factor that affects performance in discontinuously reinforced FMCs is fiber length. This has an effect primarily on the ease with which the composite can be manufactured. Very long fibers can create difficulties with methods used to create discontinuously reinforced FMCs and can result in nonuniform mechanical properties. The third factor is also related to fiber geometry, namely, the fiber shape. Recall that the... 

In summary, longitudinal propagation seems to be more sensitive to reduced sodium channel availability especially in nonuniform anisotropic tissue, and under these conditions reentrant arrhythmia can be initiated due to discontinuous propagation, whereas transverse propagation is more sensitive to un-... 

What is the role of the gap junctions By coupling the myocardial cells in both directions (longitudinal and transverse) they are responsible for the biophysical properties of the tissue. A reduction in gap junction distribution or a closure of the gap junction channels causes nonuniformities and discontinuities which alter the biophysical properties of the tissue and make it more prone to nonuniform anisotropic reentry. According to the model proposed by Krinsky [1966], a reduction in gap junctions or a closure of gap junction channels will lead to local slowing of conduction, thereby allowing smaller perimeters of reentrant arrhythmia. In addition, slowing of conduction is generally believed to be a risk factor for initiation of reentry. Since in many... 

By far the most important of the local nonuniform flow phenomena is that which occurs when supercritical flow has its velocity reduced to subcritical. We have seen in these example scenarios that there is no ordinary means of changing from lower- to upper-stage flow with a smooth transition, because the theory calls for a vertical slope of the water surface. The result, then, is a marked discontinuity in the surface, characterized by a steep upward slope of the profile, broken throughout with violent turbulence, and known universally as the hydraulic jump. 

Note The condition that e s be continuous at Rs and Rs + ARf is easily removed by adding an extra sphere-sphere terms with the required discontinuity in e. Equation numbers in [ ] as in J. E. Kiefer, V. A. Parsegian, and G. H. Weiss, "Model for van der Waals attraction between spherical particles with nonuniform adsorbed polymer," J. Colloid Interface Sci., 51, 543-545 (1975). 

The shock front created in the experimental gas is a physical and mathematical discontinuity that requires irreversible thermodynamics for description. For convenience the shock wave system is divided into three parts the parts before and after the shock front are considered to obey tile laws for reversible processes (dS = 0, etc.) so only what occurs at the discontinuity is described as an irreversible process (dS > 0). However, even at the front the laws of conservation (mass, momentum, and energy) still hold for the nonuniform, unidimensional flow of the shock wave when confined in a tube ... 

Newman further showed that when slow reaction kinetics are taken into account, the distribntion of the potential at the electrode becomes nonuniform The resulting current distribution, also called secondary current distribution, becomes more nniform than the primary current distribution [Fig. 48(b), dashed line]. The discontinuity at the end of the electrode is eliminated. 

The existence of the free surface energy can be explained by the presence of unsaturated bonds between the molecules at the interface. The formation of a new interface requires work to be performed, in order to bring molecules to the interface from the bulk. The intermolecular interactions at the interface and in the bulk of a phase are substantially different. In the vicinity of an interface, and at distances comparable with molecular dimensions, the composition and properties of individual phases are no longer continuous. This means that a nonuniform layer exists between the phases, within which a transition from properties characteristic of one phase to those characteristic of another occurs. Such a nonuniform transition layer is referred to as the physical interface of discontinuity, or simply the discontinuity surface, according to G ibbs [ 1 -3 ]. 

Nonuniform Surface Temperature. The previous section was devoted to uniform-temperature plates. In practice, however, this ideal condition seldom occurs, and it is necessary to account for the effects of surface temperature variations along the plate on the local and average convective heat transfer rates. TTiis is required especially in the regions directly downstream of surface temperature discontinuities, e.g., at seams between dissimilar structural elements in poor thermal contact. These effects cannot be accounted for by merely utilizing heat transfer coefficients corresponding to a uniform surface temperature coupled with the local enthalpy or temperature potentials. Such an approach not only leads to serious errors in magnitude of the local heat flux, but can yield the wrong direction, i.e., whether the heat flow is into or out of the surface. 

There are no standard test methods specific for discontinuous fiber (or short fiber) reinforced thermoplastics. It is also not clear whether a geometry-independent fracture parameter can be measured for these nonuniformly inhomogeneous materials. However in spite of these reservations there has been considerable work conducted towards characterizing short fiber composites for fracture toughness using the standard and other procedures outlined in the previous sections. The investigators have recognized that fracture mechanics data provide much more reliable information than the customary alternative tests for material selection and also a service performance indicator for components. 

The cooling curve in Figure 9.19 is an idealized schematic in which the discontinuities in slope occur at sharply defined temperatures. In reality the transitions from one straight line to the next on the Tt diagram are rounded and may appear continuous. Such indistinct discontinuities may be caused by too rapid cooling, supercooling, or incomplete mixing, which produces local nonuniformities in the sample. 

The complex geometry of flow padis in fractured rock results, primarily, fivm rock discontinuities that are present on aU scales, extending from the microscale of microfissures (ammig the mineral components of the rock) to the macroscale of various types of joints and fruits (29, 30). The complexity of the fracture-network geometry can cause either divergence or convergence of localized and nonuniform flow paths in different parts of fractured media, as well as cq>illary barrier effects at the intersection of flow paths. 

A common Molecular Dynamics approach in studies of confined systems at fixed chemical potential employs an isobaric, bulk-like bath surrounding the confinement. The conditions inside a field-exposed confinement (e.g., inside a capacitor) should therefore be close to (p, V, T) ones of GCMC cases [66, 68], suggesting similar electrostriction behavior. Occurrence of a field-induced expulsion of water has, however, been reported in a Molecular Dynamics study of this kind [57]. To secure proper barostat performance under strongly nonuniform and anisotropic pressure fields, and to account for the discontinuity between field/no... 

Discontinuity An abrupt nonuniform point of change in a transmission circuit that causes a disruption of normal operation. 

Electrochemical reactors show nonuniform distributions of electrode potential and hence current density. This is because electrode dimensions, however large, are finite even in the simplest situation the highest nonuniformity will occur at electrode edges and discontinuities. Current... 

Water Break The appearance of a discontinuous film of water on a surface, signifying nonuniform wetting and usually associated with a surface contamination. 

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