Interior Body Research Articles

Effect of Weather, Age, and Cyclic Pressurizations on Structural Performance of Acrylic Plastic Spherical Shells Under External Pressure Loading

Weathering, aging, and cyclic application of stresses to acrylic plastic degrades its physical properties. The rate of degradation must be known if the useful life of load-carrying acrylic structures is to be predicted with accuracy. Physical and chemical tests conducted by the authors on thick spherical shells indicate that the weathering affects only a thin surface layer of material, which after 10 years is still less than 0.020 in. thick. Similarly, pollutants in the ambient atmosphere of the pressure chamber affect the surface layer of the spherical shell facing the interior of the chamber. The physical and chemical properties of the thin surface layer affected by weathering differed significantly from those in the middle of 2.5-in.-thick Plexiglas G plate; the decrease in properties was: 40 percent in tensile elongation, 34 percent in flexure strength, 21 percent in tensile strength, and 79 percent in molecular weight. Since the interior body of the thick plastic shell is not affected by weathering or chemical attack and the affected surface layers are very thin, the ability of the shell to carry compressive loads is not significantly diminished after 10 years of service. Only an 11 percent decrease of critical pressure was observed in spherical shells with thickness of 1 in. subjected to 10 years of weathering and 2000 pressure cycles of 8 hour duration each to 30 percent of its original critical pressure. Based on the preceding data it appears safe to extend the operational life from 10 to 20 years of all acrylic plastic spherical shells with bearing surfaces normal to spherical surface designed on the basis of ANSI/ASME PVHO-1 Safety Standard for external pressure service.

Theoretical and experimental approaches to spatial aspects of electrolocation

The shape of an electric fish's field, within an aquarium of finite size, was calculated by numerical computer simulation (Figs. 3, 4). An object differing in conductivity from the surrounding water distorts the electric field of the fish. The associated changes in potential on the animal's body surface are monitored by electroreceptors and thus represent the “electric image” of the object (Fig. 6). The “intensity” of this image decays approximately with a negative power function of the distance between object and fish (Fig. 11). Body geometry, such as an elongated tail, as well as resistances of the interior body and skin are of prime importance for electrolocation performance (Figs. 7, 8, 10). Some theoretical conclusions are supported by neurophysiological and behavioral data (Figs. 12, 13), others still have to be tested experimentally.

A tachistoscopic index of body perception. I. Body boundary and body interior awareness.

Abstract Fisher and Cleveland originally proposed that individuals differ in exterior-interior body awareness. A study was conducted in a population of 61 men and 43 women to examine this hypothesis. Tachistocopic recognition times for picture categories depicting the exterior and interior (E and I) body sectors were ascertained. A chi square analysis revealed that these recognition times were significantly related (P = 0.01) to Rorschach measures reflecting E-I awareness. An additional finding was that men recognized the I category more rapidly. This was considered to provide further support for the hypothesis that men have accentuated I awareness. An outline was given of ongoing work designed to measure the extent of the tachistoscope's regional specificity.

Colored Motion Picture Photography and Black-and-White Television of the Human Urinary Bladder and Other Interior Body Organs

Colored Motion Picture Photography and Black-and-White Television of the Human Urinary Bladder and Other Interior Body Organs