Significance of deformation rate softening of memory in viscoelastic fluid mechanics and polymer processing

It is pointed out that in viscoelastic fluid constitutive equations, non-linear response to deformation rate and strain beyond the second order is usually interpreted in terms of the deformation rate or strain dependence of the memory function. These non-linearities act to decrease the extent of the memory. The dependence may be characterized by one or more dimensionless material parameters. A new dimensionless group based on the primary material parameters describing the intensity of the deformation rate dependence of the memory function is introduced and its significance is discussed. This is called the Yamamoto number. The solutions of viscoelastic fluid mechanics problems are considered to depend upon both the Weissenberg and Yamamoto numbers. Such problems include topics of interest in polymer melt processing such as uniaxial elouigatioiial flow, fiber spinning and vortex development in extrusion through a die entry.     

A method for the identification of crack-front location during fatigue fracture in polymers

An attempt has been made to accurately locate the crack-front position at intervals during fatigue cycling of low density polyethylene specimens by means of markers. Scanning electron microscopy has been used to inspect the fracture surfaces and the markers have been identified by means of the X-ray image produced by the signal from a fully focusing crystal spectrometer.     

Crystal growth of caesium tin(II) trichloro-bromides

Crystals of compounds occurring in the solid solution range CsSnBr₃-CsSnCl₃ have been prepared by pulling from the melt and by Bridgman growth. The materials show a consistent change in colour and electrical resistivity from the black metallic conductor CsSnBr₃ to the bright yellow CsSnCl₃. The as-grown compounds undergo various structure changes from the cubic, high temperature form to lower symmetry forms on standing. These changes have been followed by DTA; they are also apparent as colour changes. X-ray examination indicates that the compounds react with atmospheric moisture to form monohydrates. The products showed some differences in their structural stability from powders of the same composition precipitated from solution. These differences are attributed to particle size effects analogous to those encountered in ferroelectric perovskites.     

The artificial heart. Progress and promise

A multidisciplinary group has designed, fabricated, and evaluated an artificial heart. The heart consists of two smooth-surfaced sac-type pumps, two pneumatic power units, and an electronic control system. The artificial heart has been employed in 22 calves. A variety of problems have been encountered and overcome and a significant improvement in pump design has been made. As a result, a gradual increase in survival times has occurred. The last two calves in which the heart was tested lived for 60 and 42 days respectively. These animals ate well and gained weight. The ability of the control system to balance the output of the two pumps over long periods of time and to automatically increase cardiac output with treadmill exercise has been confirmed. No insurmountable problems in the development of the artificial heart have been identified. The date that an artificial heart will be available for clinical use depends on the availability of funds and on the tenacity of the investigators.     

Self-monitoring and the attitude–behavior relation.

130 undergraduates responded to 3 questionnaires over a 6-wk period before and after the 1980 presidential election. The questionnaires assessed self-monitoring tendency, attitudes, and intentions with respect to voting in the election and smoking marihuana, and included self-reports of actual behavior. Low self-monitors tended to exhibit stronger attitude–behavior correlations than high self-monitors. There was, however, no difference in the predictability of intentions from attitudes, a finding that disconfirmed the perceived relevance interpretation of the effect of self-monitoring. Instead, the difference was located in the relation between intentions and behavior; low self-monitors exhibited significantly stronger intention–behavior correlations than did high self-monitors. Findings support the interpretation that the 2 types of individuals are equally aware of the implications of their attitudes, but that high self-monitors, being sensitive to situational demands, are less likely to carry out their previously formed intentions than low self-monitors, who are more attentive to internal cues. (26 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effects of steroid instillations and hematomas on the pseudosheaths around miniature breast implants in rats

The syndrome of hypercalcemia in patients with renal cell carcinoma without metastasis to bone, in association with elevated levels of immunoreactive prostaglandin E and normal parathyroid hormone levels, prompted the investigation of an etiologic relationship of increased prostaglandin in this syndrome. Ethyl acetate extracts of tissue culture effluents, primary and metastatic renal cell carcinoma, and plasma were chromatographed on silicic acid columns and assayed by double antibody immunoprecipitative methods for immunoprecipitative methods for immunoreactive prostaglandins A and E. Increased levels of immunoreactive prostaglandins A and E were found 1) to be generated in parallel with cell growth during a period of time by renal cell carcinoma in monolayer growth, 2) in extracts of primary and metastatic renal cell carcinoma tissue and 3) in the venous effluent of a kidney bearing a renal cell carcinoma. These findings support the hypothesis that renal cell carcinoma can produce prostaglandins. Furthermore, reported syndromes of patients with renal cell carcinoma associated with elevated prostaglandin levels may result from the autonomous production of prostaglandins in vivo by the tumor.     

Photolithographic Fabrication and Physiological Performance of Microelectrode Arrays for Neural Stimulation

The development of an auditory cochlear prosthesis which works by direct electrical stimulation of the auditory nerve creates the need for a multielectrode stimulation array which is small in size, rugged, resistant to electrolysis, and stable and reproducible in its electrical and mechanical properties. This paper describes the fabrication of such microelectrode arrays using planar lithographic techniques.     

Liquid-crystal light valves

Liquid-crystal light valves have been built in which a relatively weak-signal image controls the flow of light to a much brighter projected image. The brightness of the projection light is limited only by heating in the light valve, and so great optical gain is possible. Brightness gains of 10?20 have been achieved with 30?W/cm2 of signal light at an efficiency of 15%. Resolutions of 5 line pairs per mm on the light valve and contrast ratios of 10:1 have been obtained, with a response time of about 0.1 s. With improvements, resolutions of 10?20 line pairs per mm relatively fast response and sensitivity to signal-light levels of nW/cm2 may be expected.     

Comprehensive provision of psychological services to students on a university campus.

A conceptual framework for a total delivery system of psychological services on a University Campus was proposed. In relation to the implementation of the Kirk Committee Report on "Standards for University Counseling Services," the objectives of intervention by provision of service were described as a) achievement by the student of a developmentally more mature level of homeostatic relationship with his environment or b) returning the student to autonomous functioning. Some of the issues involved in implementing such a system were considered, and the provision of trained staff capable of operating such a system discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)