5,629 research outputs found

    Multipurpose binocular scanning apparatus

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    Optical gimballing apparatus directs narrow fields of view throughout solid angle approaching 4 pi steradians. Image rotation produced by scanning can be eliminated or altered by gear trains directly linked to the scanning drive assembly. It provides the basis for a binocular scanning capability

    Boundary layer thickness effect on boattail drag

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    A combined experimental and analytical program was conducted to investigate the effects of boundary layer changes on the flow over high angle boattail nozzles. The tests were run on an isolated axisymmetric sting mounted model. Various boattail geometries were investigated at high subsonic speeds over a range of boundary layer thicknesses. In general, boundary layer effects were small at speeds up to Mach 0.8. However, at higher speeds significant regions of separated flow were present on the boattail. When separation was present large reductions in boattail drag resulted with increasing boundary layer thickness. The analysis predicts both of these trends

    Advanced subsonic transport propulsion

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    A brief review of the current NASA Energy Efficient Engine (E(3)) Project is presented. Included in this review are the factors that influenced the design of these turbofan engines and the advanced technology incorporated in them to reduce fuel consumption and improve environmental characteristics. In addition, factors such as the continuing spiral in fuel cost, that could influence future aircraft propulsion systems beyond those represented by the E(3) engines, are also discussed. Advanced technologies that will address these influencing factors and provide viable future propulsion systems are described. The potential importance of other propulsion system types, such as geared fans and turboshaft engines, is presented

    Investigation of Reactivity of Launch Vehicle Materials with Liquid Oxygen

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    Impact sensitivity and ignition mechanism of organic compounds in liquid oxygen correlated with chemical and physical propertie

    Reduced cortical thickness in gambling disorder: a morphometric MRI study.

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    Gambling disorder has recently been recognized as a prototype 'behavioral addiction' by virtue of its inclusion in the DSM-5 category of 'Substance-Related and Addictive Disorders.' Despite its newly acquired status and prevalence rate of 1-3 % globally, relatively little is known regarding the neurobiology of this disorder. The aim of this study was to explore cortical morphometry in untreated gambling disorder, for the first time. Subjects with gambling disorder (N = 16) free from current psychotropic medication or psychiatric comorbidities, and healthy controls (N = 17), were entered into the study and undertook magnetic resonance imaging (3T MRI). Cortical thickness was quantified using automated segmentation techniques (FreeSurfer), and group differences were identified using permutation cluster analysis, with stringent correction for multiple comparisons. Gambling disorder was associated with significant reductions (average 15.8-19.9 %) in cortical thickness, versus controls, predominantly in right frontal cortical regions. Pronounced right frontal morphometric brain abnormalities occur in gambling disorder, supporting neurobiological overlap with substance disorders and its recent reclassification as a behavioral addiction. Future work should explore the trait versus state nature of the findings and whether similarities exist with other not-yet-reclassified putative behavioral addictions.This research was supported by a grant from the National Center for Responsible Gaming to Dr. Grant. The NCRG had no further role in study design; in the collection, analysis and interpretation of data; in the writing of the report; and in the decision to submit the paper for publication.This is the author accepted manuscript. The final version is available from Springer via http://dx.doi.org/10.1007/s00406-015-0592-

    Neural and psychological underpinnings of gambling disorder: A review.

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    Gambling disorder affects 0.4 to 1.6% of adults worldwide, and is highly comorbid with other mental health disorders. This article provides a concise primer on the neural and psychological underpinnings of gambling disorder based on a selective review of the literature. Gambling disorder is associated with dysfunction across multiple cognitive domains which can be considered in terms of impulsivity and compulsivity. Neuroimaging data suggest structural and functional abnormalities of networks involved in reward processing and top-down control. Gambling disorder shows 50-60% heritability and it is likely that various neurochemical systems are implicated in the pathophysiology (including dopaminergic, glutamatergic, serotonergic, noradrenergic, and opioidergic). Elevated rates of certain personality traits (e.g. negative urgency, disinhibition), and personality disorders, are found. More research is required to evaluate whether cognitive dysfunction and personality aspects influence the longitudinal course and treatment outcome for gambling disorder. It is hoped that improved understanding of the biological and psychological components of gambling disorder, and their interactions, may lead to improved treatment approaches and raise the profile of this neglected condition.This research was supported by a Center for Excellence in Gambling Research grant by the National Center for Responsible Gaming to Dr. Grant, and a research grant from the Trichotillomania Learning Center to Mr. Odlaug, and by a research grant from the Academy of Medical Sciences (UK) to Dr. Chamberlain.This is the author accepted manuscript. The final version is available from Elsevier via http://dx.doi.org/10.1016/j.pnpbp.2015.10.00

    Transport of sediment in helical corrugated pipe

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    CER57ARC9.Includes bibliographical references.Prepared for the February 18-22, 1957 meeting of the American Society of Civil Engineers in Jackson, Mississippi
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