15,449 research outputs found

    Space shuttle main engine high pressure fuel pump aft platform seal cavity flow analysis

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    A general purpose, three-dimensional computational fluid dynamics code named PHOENICS, developed by CHAM Inc., is used to model the flow in the aft-platform seal cavity in the high pressure fuel pump of the space shuttle main engine. The model is used to predict the temperatures, velocities, and pressures in the cavity for six different sets of boundary conditions. The results are presented as input for further analysis of two known problems in the region, specifically: erratic pressures and temperatures in the adjacent coolant liner cavity and cracks in the blade shanks near the outer diameter of the aft-platform seal

    Design, Fabrication and Test of Composite Curved Frames for Helicopter Fuselage Structure

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    Aspects of curved beam effects and their importance in designing composite frame structures are discussed. The curved beam effect induces radial flange loadings which in turn causes flange curling. This curling increases the axial flange stresses and induces transverse bending. These effects are more important in composite structures due to their general inability to redistribute stresses by general yielding, such as in metal structures. A detailed finite element analysis was conducted and used in the design of composite curved frame specimens. Five specimens were statically tested and compared with predicted and test strains. The curved frame effects must be accurately accounted for to avoid premature fracture; finite element methods can accurately predict most of the stresses and no elastic relief from curved beam effects occurred in the composite frames tested. Finite element studies are presented for comparative curved beam effects on composite and metal frames

    The Role of Exosomes in Breast Cancer

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    Neuraminidase Activity in \u3cem\u3eDiplococcus pneumoniae\u3c/em\u3e

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    Kelly, R. T. (Marquette University School of Medicine, Milwaukee, Wis.), D. Greiff, and S. Farmer. Neuraminidase activity in Diplococcus pneumoniae. J. Bacteriol. 91:601–603. 1966.—A method for the quantitation of neuraminidase in the presence of N-acetylneuraminic acid aldolase is described. The neuraminidase content of Diplococcus pneumoniae was found to be dependent on the media employed for growth; the highest enzyme activity per milligram of bacterial protein was obtained with Todd-Hewitt broth. Neuraminidase production was stimulated in D. pneumoniae by the addition of N-acetylneuraminlactose, N-acetylneuraminic acid, or N-acetylmannosamine to the growth medium. Three rough strains of D. pneumoniae, which were nonpathogenic for mice, lacked neuraminidase activity. Seven of 12 smooth strains contained neuraminidase; enzyme activity was not detected in the remaining 5 smooth strains. There was no correlation between the presence of neuraminidase activity and the capsular type or between neuraminidase production and animal virulence

    Taking “Fun and Games” Seriously: Proposing the Hedonic-Motivation System Adoption Model (HMSAM)

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    Hedonic-motivation systems (HMS)—systems used primarily to fulfill users’ intrinsic motivations—are the elephant in the room for IS research. Growth in HMS sales has outperformed utilitarian-motivation systems (UMS) sales for more than a decade, generating billions in revenue annually; yet IS research focuses mostly on UMS. In this study, we explain the role of intrinsic motivations in systems use and propose the hedonic-motivation system adoption model (HMSAM) to improve the understanding of HMS adoption. Instead of a minor, general TAM extension, HMSAM is an HMS-specific system acceptance model based on an alternative theoretical perspective, which is in turn grounded in flow-based cognitive absorption (CA). The HMSAM extends van der Heijden’s (2004) model of hedonic system adoption by including CA as a key mediator of perceived ease of use (PEOU) and of behavioral intentions to use (BIU) hedonic-motivation systems. Results from experiments involving 665 participants confirm that, in a hedonic context, CA is a more powerful and appropriate predictor of BIU than PEOU or joy, and that the effect of PEOU on BIU is fully mediated by CA sub-constructs. This study lays a foundation, provides guidance, and opens up avenues for future HMS, UMS, and mixed-motivation system research

    Bingham Dai, Adolf Storfer, and the tentative beginnings of psychoanalytic culture in China, 1935-1941.

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    This paper looks at the work of two figures who, while marginal to theoretical developments within the history of psychoanalysis, each briefly played an important role in the dissemination of analytical ideas in China, contributing to an early psychoanalytic culture there. Bingham Dai, a native of China, while studying for a PhD in sociology at Chicago, received instruction from Harry Stack Sullivan and a psychoanalytic training under Karen Horney's supervision. However, the neo-Freudian outlook with which this experience imbued him had its roots in an earlier encounter with his experiments in personality education first conducted on students in a Tientsin high school, and later in Shantung under the direction of the conservative Confucian scholar and reformer, Liang Shu Ming. These experiences convinced him that a less orthodox psychoanalytic perspective was what Chinese patients with psychological problems required. He returned in 1935 to teach medical psychology to doctors at Peking Union Medical College, taking a few into analysis and treating some patients. However, the Sino-Japanese war brought these activities to a close and he left in 1939, just a few months after the former Freud publisher and Viennese émigré, Adolf Storfer, arrived. Storfer set about publishing "Gelbe Post," a German language periodical replete with articles on psychoanalysis, linguistics and Chinese culture. But limited finances, severe competition from a rival publisher, plus his own ill health, forced him to abandon this in spite of the support offered him through the many contributors in the international psychoanalytic community whose articles he published. The paper concludes by considering the relative historiographic fate of the men upon whom subsequent scholarship has been very unevenly focused.published_or_final_versio
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