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The mechanisms which have been suggested to explain the deformation of crystalline polymers are reviewed. Emphasis has been placed upon the type of information that can be gained from experimental observations and on the extent to which those observations are consistent with suggested deformation mechanisms and current ideas on polymer structure and morphology.

A study was made of the relation between breaking load and deformation in breakdown of porous anion exchange resins and the overall pore volume, mean effective pore radius and degree of crosslinking. It was shown that with an increase in overall volume and mean effective pore radius by one order of magnitude, breaking load decreases by 2 orders and breaking deformation decreases by half. It was found that a reduction in the mean effective pore radius to 60 A considerably increases breaking behaviour. Breaking deformation is mainly affected by the mean effective pore radius and the degree of crosslinking. Breaking behaviour is thus fairly sensitive to a variation in structural parameters of porous anion exchange resins.

Oscillatory magnetostriction and the de Haas-van Alphen effect have been used to determine Fermi surface deformation parameters for cross sections lying normal to[001] in white tin. The temperature dependence of the amplitudes has been used to calculate effective masses for orbits lying normal to[001], [100], and[110].

This paper describes recent developments in the nonlinear deformation and ultimate load analysis of prestressed concrete reactor vessels using finite elements. First, a number of finite element models are called into attention for the idealization of composite structures such as reinforced and prestressed concrete components. Then different inelastic constitutive models are proposed for the behaviour of concrete in the pre- and post-failure regime. Subsequently various numerical techniques are examined for the solution of nonlinear problems, especially with regard to their distortion of the constitutive model. In conclusion these modelling techniques are applied to the analysis of four typical examples, the nonlinear deformation analysis of a concrete specimen subjected to biaxial compression, the crack analysis of a thick-walled concrete cylinder, the overload analysis of the THTR 1 : 5 scale model, and the ultimate load analysis of a concrete top closure model.

Swirling flows have been commonly used for a number of years for the stabilization of high-intensity combustion processes. In general these swirling flows are poorly understood because of their compelexity. This paper describes the recent progress in understanding and using these swirling flows. The main effects of swirl are to improve flame stability as a result of the formation of toroidal recirculation zones and to reduce combustion lengths by producing high rates of entrainment of the ambient fluid and fast mixing, particularly near to the boundaries of recirculation zones. Two main types of swirl combustor can be identified as follows: The Swirl Burner. Here swirling flow exhausts into a furnace or cavity combustion occurs in and just outside the burner exit. The Cyclone Combustion Chamber. Here air is injected tangentially into a large, usually, cylindrical chamber and exhausts through a centrally located exit hole in one end. Combustion mostly occurs inside the cyclone chamber. Initially the isothermal performance of swirl combustors is considered, and it is demonstrated that, contrary to many previous assumptions, the flow is often not axisymmetric but three-dimensional time-dependent. Under most normal nonpremixed combustion conditions, the swirling flow returns to axisymmetry, although there is still a residual presence of the three-dimensionality, particularly on the boundary of the reverse flow zone. Swirl increases considerably the stability limits of most flames; in fact with certain swirl burners, the blow-off limits are virtually infinite. Cyclone combustion chambers have large internal reverse flow zones which provide very long residence times for the fuel/air mixture. They are typically used for the combustion of difficult materials such as poor quality coal or vegetable refuse. In contrast to the swirl burner which usually has one central toroidal, recirculation zone, the cyclone combustor often has up to three concentric toroidal recirculation zones. Sufficient information is also available to indicate that stratified or staged fuel or air entry may be used to minimize noise, hydrocarbon, and NOx emissions from swirl combustors.

The effect of repetitive deformation on the dielectric loss tangent tanδ and permittivity ɛ of alkali—halide dielectrics was studied. A definite correlation has been established between the trends of tanδ and ɛ on the one hand and the number of deformation cycles as well as the character of changes in the dislocation structure on the other.

Approximate closed-form solutions are obtained for the static stress and deformation as well as the stability of an orthotropic layered shell of revolution with properties which vary along the meridian and through the wall thickness. The shell is subjected to axisymmetrical load and temperature distributions. The nonlinear “prestress” or “pressurization” effect is taken into consideration. It is of interest that due to the nonhomogeneity of the shell wall significant bending stresses can occur far from support points. The asymptotic results agree with numerical values obtained from two computer programs using direct numerical methods, even for shells that are relatively shallow.

The three-dimensional pattern of Richardson numbers in isentropic co-ordinates is investigated for a case study of a mid-tropospheric baroclinic zone for which special three-hourly radiosonde data are available. Results show that the lowest Richardson number values are found within the baroclinic zone with most values between 0.25 and 1.0. An equation developed by Roach (1970) was used to relate observed versus computed changes of d/dt (In Ri) in isentropic co-ordinates throughout the baroclinic zone. In general stretching deformation contributed to an increase of In Ri in downstream regions of the baroclinic zone whereas the converse was true for shearing deformation in mid- and upstream regions of the baroclinic zone. Overall agreement between computed and observed changes ranged from poor outside the baroclinic zone to fair to good within the zone. Air parcels entering the upstream region of the baroclinic zone underwent both frontogenesis and decrease in In Ri. The reverse was noted in the downstream region of the baroclinic zone.

By using the method of scanning electron microscopy, a visual study was made of the macro-deformation of spherulitic deformation during the cold rolling of poly(ethylene terephthalate) (PET) and poly(tetramethylene terephthalate) (PTMT). By rolling solution cast films to different extension ratios, it was found that the surface material (nearest the rollers) appeared to deform first by the shearing action. With higher extension, the material toward the core of the film began to deform. In all cases, the deformation process tended to flatten the spherulites yet, in general, the spherulitic boundaries were maintained. It was noted that the same general behavior was observed for both PET and PTMT.

Calculated dispersion curves and frequency spectra are presented for CsCl, CsBr and CsI. These calculations have been made using the deformation dipole model including both first and second neighbor non-coulomb forces. The best fit to the experimental results is provided by a simple five parameter first neighbor model.

It has been established that, in the deformation of sintered strip materials at h0/b

The stability and classification of steady‐profile plane shocks in liquids are studied by hydrodynamic equations which include the relaxational properties of momentum and heat fluxes. The thermodynamic behavior during shock deformation is shown to be equivalent to the dissipative motion of a particle described by a generalized Lienard equation. The stability condition produces relations for the relaxation times for momentum and heat fluxes. These relations are in agreement with acoustic data and other theoretical calculations which produce the relaxation times of 10−13−10−14 sec.

We have calculated the pressure coefficients of the main gaps in Si, using the Empirical Pseudopotential Method (EPM). We find a trend toward metallization at high hydrostatic pressures. The deformation potential at the top of the valence band for uniaxial stress along the (0, 0, 1) direction is also obtained. All of the calculated pressure coefficients are in good agreement with experiment.

Road networks in developing countries are improved unevenly. Improvements are determined more by the amount of public investment than by technological breakthroughs. Improvements make drastic changes in the distances in hours between cities. An index based on mean speed between cities and population provides a measure of the rentability of road investment. Multidimensional scaling reveals some topological properties of the network, which does not fit, in general, in a conventional space of two dimensions, but does fit in spaces of three or seven dimensions.

Structural studies on hydrogen bonding in segmented polyurethane-urea elastomers were made using IR spectroscopy. Further, the orientation behavior of both the hard and soft segments on deformation was investigated using IR dichroism measurements. Hydrogen bonding was found to be formed not only between the hard segments but also between the soft segments, through urea and urethane groups, respectively. Changes in the extent of hydrogen bonding on deformation were related to segmental orientation behavior, and mechanical properties such as stress-strain and stress hysteresis. The hard segments orient preferably transverse to the stretch direction to high elongations, and show hysteresis of orientation on cyclic straining. The orientation behavior of the soft segments is approximately reversible on repeated deformation. In the range of comparatively small elongation, however, the deformation of the soft segments is larger than the external deformation. From these experimental facts, the mechanism ...

Using recently compiled data for band-head energies of 53 odd- A rare-earth nuclei, rotational models for strongly deformed nuclei have been used to determine the variation of deformations, spin-orbit parameter κ and the l 2 parameter, μ, in these nuclei. The deformation is found to be consistent with experimental deformations within 20 %. The spin-orbit parameter, κ, is found to vary from 0.037 up to 0.070, a 25 % variation from Nilsson's 0.050. The l 2 parameter μ is found to vary from 0.30 up to 0.71, a 30 % variation from Nilsson's 0.45. The trends observed in the values of spin-orbit strength C indicate a correlation with deformation, δ. Simultaneous shifts of the l 2 strength D for neutron numbers 95–97 and 101–103 may be interpreted as a sudden shift in the squareness of the potential well possibly caused by shell filling. Inclusion of hexadecapole deformation greatly improves the band-head energies for the mass region 150 ≦ A ≦ 165.

In the southern part of the South American continent a marginal basin opened behind an active andesitic island arc in the earliest Cretaceous. The basin closed again in the middle Cretaceous, during the period of fast seafloor spreading, causing the penetrative deformation of the southern Andean Cordillera.

The most recent tectonic deformation of the Zagros, and in particular the late Quaternary right-lateral wrench movement along the Main Recent Fault, is summarized in the context of the general tectonic history of the range. The seismicity along the Main Recent Fault between latitudes 33 and 35° N is examined, and details are given for several destructive earthquakes, including the 1909 Selakhor earthquake which was associated with over 40 km of surface faulting along a segment of the Main Recent Fault and which is described here for the first time. The relation between the seismicity and the individual fault segments forming the Main Recent Fault is studied and interpreted in terms of a continuing right-lateral strike slip deformation. The implications of this contemporary deformation for the seismotectonics of the Zagros are considered, and in particular its bearing on the problem of the relative motion of the Arabian Plate with respect to Central Iran.

The low-energy spectra of186Hg and184Hg are interpreted by a mixing of spherical and deformed states for angular momentum I=2, 4. In order to establish agreement between experimental results on186Hg and184Hg and potential calculations, a stronger isospin dependence of the pairing interaction is introduced. The existence of shape-isomeric states for186Hg,184Hg with a life-time ≈10−8 sec is concluded from the model. The particle-vibration coupling is discussed as the probable origin for the odd-even staggering of the ground-state deformation.

Some of the problems involving instrumentation of embankments built on soft soil can be minimized by housing instruments within a tunnel, as described in this note. The performance of the tunnel and its installation technique are presented.

A new model of the fluid-filled articular cartilage in human joints is introduced. It is a composite which can imbibe and exudate across the surface and offers resistance in tension and compression, while preserving the essential nonlinearity. The model makes tractable transient static or moving contact problems whose solutions are paramount in the study of failure criteria associated with arthritic conditions. In two examples, indentation—time characteristics and friction coefficient, based on deformation theory, are found and they agree with measured values. Moreover, a third example illustrates the mutual inclusiveness of the two leading theories: the weeping and boosted lubrication theories.

It has been shown experimentally that preliminary orientation leads to a change in the mechanical properties of polymers, a decrease in the actual contact area and a corresponding reduction of the deformation and adhesion components of the forces of friction.

On the basis of theoretical considerations, it was established that strip thickness variation in the rolling of sintered materials affects the rolling force. An expression has been derived describing the relationship between the permissible rolling force variation and the tolerance limit for a given type of product. The fact that these two quantities are interrelated shows the need for control of the rolling force in the deformation of sintered materials. The densification rolling of comparatively wide and thin strip with narrow thickness tolerances should be performed in four-high mills with regulation of roll pass geometry and roll stand stress or in cluster mills.

The flow is considered of an elastoviscous fluid whose deformation state is expressed by means of kinematic matrices in the form of a thin layer between two rotating coaxial cones with the same angular velocity.

The experimental procedure and the processing of results on the nonlinear periodic deformation of polymeric and dispersed system melts are examined. Experimental data are given on the effect of the amplitude of harmonic deformation on nonlinear stress distortions.

A numerical model has been developed to investigate water films or shells on ice pellets and hailstones with radii from 0.1 to 0.5 cm. The model considers a hydrometeor consisting of a rigid, spherical ice core of density 0.9 gm cm−3 surrounded by a shell or film of water. The water volume of the hydrometeor is assumed to be conserved. A set of deformation equations for the water film is constructed from a series expansion of an equation which is based on the balance of pressures acting on the hydrometeor. The results indicate that an ice pellet or hailstone with radius 0.45 cm radius a rather unrealistic water distribution is obtained from the present model.

On the basis of experimental data obtained in uniaxial and symmetrical and nonsymmetrical biaxial tension and pure shear, the deformation behavior of unfilled and filled butadiene-nitrile rubbers is described by means of the Bartenev-Khazanovich one-parameter high-elastic potential.

The deformation of grain boundaries by crystal lattice dislocations is discussed in detail for the case of symmetric boundaries in simple cubic structures. In particular, It is shown that the motion of grain boundary dislocations that are generated as a result of various combinations of crystal lattice dislocations gives rise to either grain boundary sliding or grain boundary migration or both. The structure and motion of various types of ledges such as glide ledges, climb ledges, and compensated and uncompensated ledges are considered in this analysis. Although the analysis is done for simple cubic structures, the concepts developed are quite general and can be applied to more complex crystal structures. It is also shown that some of the grain boundary dislocation arrays can be suitably described as disclination dipoles, and such a dualistic representation is used to interpret the shape changes associated with the grain boundary deformation.

In this paper the presence of a ped structure in clay formation is recognized. The total response deformation representing the macro-rheological behaviour accounts for the integral effect of individual ped performance characteristics. The summation orVolterra-Boltzmann integral accounting for the different structural strengths of the various peds is introduced in the analysis, incorporating thereby the probability of occurrence of each structural state. The utilization of this probability is likened in essence to a weighing factor of the contribution of each structural state, leading to the derivation of the mathematical expectation of the total deformation.

A study on the mechanical properties of rubbery polymers under finite deformation is presented here using the biaxial stress relaxation method for the experimental study. In the first part...

Optical isotope shifts of four lines in the atomic spectrum of xenon have been measured using enriched samples of all stable xenon isotopes. The spectrograms were recorded with the aid of a pressure-scanned Fabry-Perot interferometer and analysed by digital data techniques. The measured isotope shifts are shown to be self-consistent by means of a King plot. An estimate of the specific mass effect is given and the changesδ 〈r 2〉 of the mean square radius of the nuclear charge distribution are extracted from the measured shifts. These changesδ 〈r 2〉 are discussed in terms of the nuclear deformation parameterβ 2. The results for the deformation of the stable even xenon isotopes are shown to be in good agreement with the systematic of deformation found for the neighbouring elements from Coulomb excitation experiments.