1,002 research outputs found
SPAR improved structure/fluid dynamic analysis capability
The capability of analyzing a coupled dynamic system of flowing fluid and elastic structure was added to the SPAR computer code. A method, developed and adopted for use in SPAR utilizes the existing assumed stress hybrid plan element in SPAR. An operational mode was incorporated in SPAR which provides the capability for analyzing the flaw of a two dimensional, incompressible, viscous fluid within rigid boundaries. Equations were developed to provide for the eventual analysis of the interaction of such fluids with an elastic solid
A hybrid-stress finite element for linear anisotropic elasticity
Standard assumed displacement finite elements with anisotropic material properties perform poorly in complex stress fields such as combined bending and shear and combined bending and torsion. A set of three dimensional hybrid-stress brick elements were developed with fully anisotropic material properties. Both eight-node and twenty-node bricks were developed based on the symmetry group theory of Punch and Atluri. An eight-node brick was also developed using complete polynomials and stress basis functions and reducing the order of the resulting stress parameter matrix by applying equilibrium constraints and stress compatibility constraints. Here the stress compatibility constraints must be formulated assuming anisotropic material properties. The performance of these elements was examined in numerical examples covering a broad range of stress distributions. The stress predictions show significant improvement over the assumed displacement elements but the calculation time is increased
Spatial autocorrelation in biology 1. Methodology
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74811/1/j.1095-8312.1978.tb00013.x.pd
Spatial autocorrelation in biology 2. Some biological implications and four applications of evolutionary and ecological interest
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72158/1/j.1095-8312.1978.tb00014.x.pd
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Fuzzy Implication Formation in Distributed Associative Memory
An analysis is presented of the emergence of implicational relations within associative memory systems. Implication is first formulated within the framework of Zadeh's theory of approximate reasoning. In this framework, implication is seen to be a fuzzy relation holding between linguistic variables, that is, variables taking linguistic terms (e.g., "young", "very old") as values. The conditional expressions that obtain from this formulation may be naturally cast in terms of vectors and matrices representing the membership functions of the fuzzy sets that, in turn, represent the various linguistic terms and fuzzy relations. The resulting linear algebraic equations are shown to directly correspond to those that specify the operation of certain distributed associative connectionist memory systems. In terms of this correspondence, implication as a fuzzy relation can be seen to arise within the associative memory by means of the operation of standard unsupervised learning procedures. That is, implication emerges as a simple and direct result of experience with instances of events over which the implicational relationship applies. This is illustrated with an example of emergent implication in a natural coarsely coded sensory system. The percepts implied by sensory inputs in this example are seen to exhibit properties that have, in fact, been observed in the system in nature. Thus, the approach appears to have promise for accounting for the induction of implicational structures in cognitive systems
Language-Naive Chimpanzees (Pan troglodytes) Judge Relations Between Relations in a Conceptual Matching-to-Sample Task
Three chimpanzees with a history of conditional and numeric token training spontaneously matched relations between relations under conditions of nondifferential reinforcement. Heretofore, this conceptual ability was demonstrated only in language-trained chimpanzees. The performance levels of the language-naive animals in this study, however, were equivalent to those of a 4th animal—Sarah—whose history included language training and analogical problem solving. There was no evidence that associative factors mediated successful performance in any of the animals. Prior claims of a profound disparity between language-trained and language-naive chimpanzees apparently can be attributed to prior experience with arbitrary tokens consistently associated with abstract relations and not language per se
High-Throughput Screening of Shape Memory Alloy Thin-Film Spreads using Nanoindentation
We have demonstrated the utility of nanoindentation as a rapid characterization tool for mapping shape memoryalloy compositions in combinatorial thin-film libraries. Nanoindentation was performed on Ni–Mn–Al ternary composition spreads. The indentation hardness and the reduced elastic modulus were mapped across a large fraction of the ternary phase diagram. The large shape memoryalloy composition region, located around the Heusler composition (Ni2MnAl), was found to display significant departure in these mechanical properties from the rest of the composition spread. In particular, the modulus and the hardness values are lower for the martensite region than those of the rest of the phase diagram
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