Deformation compressional

Folds are features related to compressional, ductile deformation (Fig. 5.10). They form some of the largest reservoir structures known. A fold pair consists of anticline and syncline. 

In simple shear flow where vorticity and extensional rate are equal in magnitude (cf. Eq. (79), Sect. 4), the molecular coil rotates in the transverse velocity gradient and interacts successively for a limited time with the elongational and the compressional flow component during each turn. Because of the finite relaxation time (xz) of the chain, it is believed that the macromolecule can no more follow these alternative deformations and remains in a steady deformed state above some critical shear rate (y ) given by [193] (Fig. 65) ... 

Heckel proposed that a correlation exists between yield strength and an empirically determined constant, K, which is a measure of the ability of the compact to deform [28,112]. He discovered that, indeed, K is inversely proportional to yield strength. Further, he derived an equation expressing the relationship between the density of a compact and the compressional force applied. This relationship is based on the assumption that decreasing void space (i.e., decreasing porosity) of a compact follows a first order rate process ... 

Step 4 Capsule Mechanical Stability. The mechanical stability of the membranes was assessed semi-quantitatively by applying a compressional force via a micrometer. While this method is not precise, it did permit us to assess if the capsules could withstand deformations and if they ruptured in a controlled or catastrophic manner. Another test which was selectively employed was to place capsules between microscope slides and measure the force required to compromise the integrity of the membrane. These tests measured the resistance of the weakest point of the membrane. For certain capsules a needle was used to probe the breaking strength of a local region of the membrane. 

The specific material properties of most import to the compaction operation are elastic deformation behavior, plastic deformation behavior, and viscoelastic properties. These are also referred to as mechanisms of deformation. As mentioned earlier, they are equally important during compression and decompression i.e., the application of the compressional load to form the tablet, and the removal of the compressional load to allow tablet ejection. Elastic recovery during this decompression stage can result in tablet capping and lamination. 

E.B. Bagley, D.D. Christianson and W.J. Wolf, Frictional Effects in Compressional Deformation of Gelatin and Starch Gels and Comparison of Material Response in Simple Shear, Torsion and Lubricated Uniaxial Compression, J. Rheol., 29 103-108 (1985). 

In the following sections, I review a few, commonly-cited models of widespread compressional and extensional deformation and consider their respective elevation predictions. This review is not meant to be an exhaustive list of all possible mechanisms of elevation change due to continental deformation. Rather, the purpose is to illustrate the role of elevation as a parameter that can be used to constrain mechanisms of continental deformation. 

When two elastic and frictionless spheres are brought into contact under compressional forces or pressures, deformation occurs. The maximum displacement and contact area depend not only on the compressional force but also on the elastic material properties and radii of the spheres. The contact between two elastic and frictionless spherical bodies under compression was first investigated by Hertz (1881) and is known as the Hertzian contact. 

Prediction of the restitution coefficient has been a challenging research topic for decades. Unfortunately, no reliable and accurate prediction method has been found so far. However, some useful simplified models with certain limits have been developed. One of them is the elastic-plastic impact model in which the compression process is assumed to be plastic with part of the kinetic energy stored for later elastic rebounding, with the rebound process considered to be completely elastic [Johnson, 1985]. In this model, it is postulated that (1) during the plastic compression process, a — r3/2a (2) during the compression process, the averaged contact pressure pm is constant and is equal to 3 Y and (3) the elastic rebound process starts when maximum deformation is reached. Therefore, the compressional force is... 

When a force is applied to a material, deformation occurs. When this deformation completely disappears after cessation of the external force, further deformation occurs. Deformations that do not completely recover after release of the stress are known as plastic deformations. The force required to initiate a plastic deformation is known as the yield stress. When the particles are so closely packed that no further filling of the voids can occur, a further increase of the compressional force causes deformation at the points of contact. Both plastic and elastic deformation may occur,... 

Tablets. SEM was widely used to investigate the structure of tablets. An excellent review is presented by Hess. " Imaging of tablets is a useful tool to demonstrate differences in compression behavior of substances. Fig. 24 shows an example where the plastically deforming spray-dried sorbitol instant was compressed together with the more brittle ascorbic acid in one tablet. At low compressional force of 5 kN for a 10 mm tablet, the rectangular ascorbic acid crystals as well as the partially deformed sorbitol particles are visible (Fig. 24A). In Figs. 24A and B, the surfaces of two tablets compressed at 5 kN and 30 kN are compared. At higher compressional forces, a uniform, flat, and smooth tablet surface is formed, but within this surface a single unchanged ascorbic acid crystal could be detected. Observation of a broken tablet (Fig. 24C), which was prepared at a high compressional force of 30 kN, reveals that the ascorbic acid crystal is totally fixed within a matrix of plastically...

David and Augsburger (63) studied the decay of compressional forces for a variety of excipients, compressed with flat-faced punches on a Stokes rotary press. They found that initial compressive force could be subject to a fairly rapid decay and that this rate was dependent on the deformation behavior of the excipient for the materials studied, they found that maximum loss in compression force was for compressible starch and MCC, which was followed by compressible sugar and DCP. This was attributed to differences in the extent of plastic flow. The decay curves were analyzed using the Maxwell model of viscoelastic behavior. Maxwell model implies first order decay of compression force. 

Ziegler, P.A., 1987. Late Cretaceous and Cenozoic intra-plate compressional deformations in the Alpine foreland -a geodynamic model. Tectonophysics, 137, pp. 389-420... 

Tectonic breaching within the GEA is mostly related to Cretaceous to Tertiary compressional or tran-spressional deformation and is manifested by two processes. Firstly, extension occurs above the neutral surface of inversion folds (Fig. 8a), thereby creating a pattern of radial tension fractures, extending upwards from the seal into the overlying section. Radial fractures will not form below the neutral surface of the fold limb which is in compression. As a consequence, reservoir objectives lying above or close to the neu-... 

For small stresses the modulus is a constant and the material behaves elastically. It returns to its original condition when the stress is removed. For larger stresses, the elastic limit may be exceeded, and the sample undergoes a permanent, or plasic, deformation. Important stresses are compressional stresses, in which the force acts in one dimension only hydrostatic, in which the force acts equally in all directions and shearing, in which forces act to move parallel planes of the sample past each other. 

Good results are obtained with the Kawabata approach, which measures several different mechanical properties of the fabric at the same time. The Kawabata evaluation system for fabrics uses four devices measuring the tensile and shearing, pure bending, and compressional properties, and surface characteristics of fabrics. Key parameters are the applied force, the rate of deformation, and the tension on the sample. By comparison with subjectively evaluated standards, statistical correlations can be drawn, leading to the objective quantification of fabric softness. The method, however, is too complex for routine work [26], Some other methods are reviewed by Mooney [52] ... 

Mountain building usually involves compressional deformation of the crust. Recent studies of the... 

Here B is again a compressional elastic constant, is a bend elastic constant and the elastic constant C results from an elliptical deformation of the rods (this term is absent if the column is liquid). 

G, the shear modulus for shear deformation and B, the bulk modulus for compressional deformation. 

By contrast, sediment creep is a process of slow strain due to constant load-induced stress that may extend over periods ranging from hours to thousands of years (Watkins and Kraft, 1978). Creep may occur on very gentle slopes, involving a small amount of deformation revealed by small displacements, compressional folds, faults, and pull-apart features that act as precursors to slides and slumps (Almagor and Wiseman, 1977 Hill et al., 1982). 

The molecular orientation in the film occurs when the relaxation time of the solution becomes longer than the characteristic time for the biaxial deformation applied by the compressional stress due to the solvent evaporation, which was quantitatively calculated by Croll [13]. Therefore, the evaporation rate has to be considered to discuss the birefringence in a solution-cast film. 

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