Upon sector elements for two-dimensional problems

Different sector elements for two-dimensional problems for linear elastic analysis are developed and their utility for different types of problems is discussed. One of these elements (Type 1) fulfils the rigid body criterion for the two translatory motions as well as interelement compatibility conditions. This element is used together with a triangular element for the solution of Kirsch's problem. A considerable accuracy of the results is obtained with a relatively small number of elements.     

Imagery-perception interaction depends on the shape of the image: A reply to Farah (1989).

M. J. Farah (see record 1989-31784-001) reported that point threshold stimuli are detected better if they appear at spatial locations in the visual field that are covered by an image. By replicating her experiment with 3 instead of the original 2 images, it was found that the effect depends on the shape of the mentally projected image. A 2nd experiment with 9 different shapes revealed that the effect is modulated by the compactness and the size of the image; it is enhanced with increasing compactness and attenuated with increasing size. These findings do not unequivocally support the idea that imagery and perception interact because both processes share the same representational medium. Rather, they suggest that imagery can cause a figure–ground segregation in the visual field and that the shape of the figure may determine the amount of attention that is allocated to different sections in the visual field. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Blowing of oriented PET bottles: Predictions of free blown size and shape

A model of the blowing process for polyethylene terephthalate stretch blowmolded bottles is presented. This model uses a rubber constitutive relation. The free blown diameter and the stretch balance are derived from stress equilibrium. Free blow experiments show good agreement with the predictions.     

Separation of rhesus monkey juveniles of the same sex.

Studied juvenile-juvenile separations, using 6 like-sexed pairs of rhesus monkeys. A. J. Bowlby (see pa, vol. 36:1hk51b) separation syndrome was observed and compared to mother-infant separations reported elsewhere. Similarities were greatest during the period of separation itself. The differences between the 2 dyads were most marked during reunion. Juvenile monkeys initially ignore or avoid each other during reunion while mothers and infants usually directly return to one another. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Vorgänge bei der Bildung primärer Desoxydationsprodukte in Stählen

Desoxydation unlegierter Stahlschmelzen mit Titan; Versuchsdurchführung. Auswertung der Ergebnisse für die verschiedenen Eisenschmelzen mit Vergleichen zur Aluminiumdesoxydation. Deutung der Versuchsergebnisse. Einschlußuntersuchung mittels Rückstandsuntersuchung. Desoxydation nichtrostender Chrom-Nickel-Stähle mit Aluminium. Folgerungen.     

MIXING POLYMERS OF DIFFERENT VISCOSITIES

The mixing of viscous polymers of dissimilar viscosities undergoing an overall shear is considered. Data are presented to illustrate the effects of component viscosity ratio and relative volume fraction on the quality of mixing. Experiments and analysis are based upon the geometry suggested by a tumbled mixture of polyethylene pellets in the hopper of an extruder. For a system in which the viscosity of the initially disperse phase exceeds that of the major component, deformation is modelled as the elongation of circular cylinders resulting from heightened shear stresses and discontinuous normal stresses at the component interface. In fluids as viscous as the polymers considered, these stresses are strongly dependent upon the cross-sectional area of the mixing channel, and the interaction between elongating drops is modelled as a decreasing effective cross-sectional area. 1t is shown that the interaction between neighboring drops is sufficiently strong that at a certain drop length the disperse phase begins to behave as if it were present continuously across the mixing channel; in other words, the disperse phase and suspending medium behave at large strains like high-modulus reinforcing fibers in a lower-modulus solid matrix. This critical drop length is surprisingly small, ranging from 2 to 8 times the nominal linear dimension of the undeformed drop in the systems considered. For a system in which the major component is more viscous than the disperse drops, such a condition of substantially equal strain is shown to exist throughout the mixture.     

Schwingungserscheinungen in Chemieanlagen

Vibrational phenomena in chemical plant. This article draws on the practical experience of the author to provide a survey of vibrational problems in chemical plant and of their sources. Even though it is not always possible to eliminate all potential sources of vibration by appropriate calculation and design measures during the planning stage, they can usually be quickly identified subsequently by suitable measuring techniques and countermeasures adopted.