5,657 research outputs found

    Measurement of surface velocity fields

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    A new technique for measuring surface velocity fields is briefly described. It determines the surface velocity vector as a function of location and time by the analysis of thermal fluctuations of the surface profile in a small domain around the point of interest. The apparatus now being constructed will be used in a series of experiments involving flow fields established by temperature gradients imposed along a surface

    On the temperature of surfaces

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    The concept of the temperature of a surface is introduced from the viewpoint of the physical chemistry of surfaces. The surface, near surface and microlayer regions of the interface are defined. Most methods measure the temperature of the microlayer or at best the near surface region and may err in representing the surface temperature. Methods based on capillary ripples actually measure the surface temperature since surface tension (or surface tension tensor when a monolayer has been spread or absorbed at the interface) is the main restoring force that controls their propagation. Light scattering methods are described for determining the elevation of very small amplitude capillary waves through the computation of various correlation functions from which the surface tension can be estimated. Procedures for estimating the surface temperature are described

    DISSUADING YOUNG POTENTIAL TERRORISTS

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    After the 9/11 attacks, the United States has made many sacrifices to combat terrorism; this includes losing almost 7000 service members in the campaigns of the War on Terror. The United States has spent nearly $3 trillion on counterterrorism funding between fiscal years 2002 and 2017. Instead of being reactive in the fight against terrorism, I examine how to steer the next generation of potential terrorists in another direction. Using mentor programs like Big Brothers Big Sisters and Rancho Cielo as an exploratory proof of concept, I investigate the role proactive mentorship programs have on at-risk youth in a variety of social and culturally diverse settings. At-risk youth that are exposed to mentorship programs throughout the world where they develop sincere and lasting relationships with their mentors will be less vulnerable to being drawn into a gang or terrorist group. Joseph Campbell’s Hero with a Thousand Faces and the hero’s journey serve as the framework of analysis for the mentor programs worldwide and specifically how a mentor inserts him- or herself into the life of an at-risk youth. The examined mentor programs and relationships revealed some positive effects; however, the results are unclear because the programs have only been recently implemented—more time is required to understand lasting results. Not all at-risk youth will benefit from mentorship; however, the programs’ efforts enable some misguided youth the opportunity to live a life free of crime.http://archive.org/details/dissuadingyoungp1094562695Lieutenant, United States NavyApproved for public release; distribution is unlimited

    Norfolk Fire Rescue officers\u27 attitudes and perceptions towards cell phones and email

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    This study investigated Norfolk Fire-Rescue (NFR) officers\u27 attitudes and perception toward cell phones/email. What are the attitudes of NFR towards email/cell phones? What negative aspects of email/cell phones are affecting NFR? Do the negative aspects of information technologies increase with rank? Do the officers of NFR feel that classes aimed at technological stress or information overload, would be beneficial to the department? NFR officers responded to a forced-choice survey about negative impact of cell phones/email focusing on use patterns, perceptions of negative impact, and attitudes towards cell phones/email. NFR officers are very supportive of email/cell phones, despite the negative affects that they may be experiencing across multiple dysfunctional areas. Chiefs reported higher levels of negative perceptions than Lieutenants and Captains, demonstrating that negative impacts of cell phones/email may increase with rank. Additionally, 75% of respondents believed classes addressing technological stress or information overload would be beneficial to NFR

    Identification of proteins in the postsynaptic density fraction by mass spectrometry

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    Our understanding of the organization of postsynaptic signaling systems at excitatory synapses has been aided by the identification of proteins in the postsynaptic density (PSD) fraction, a subcellular fraction enriched in structures with the morphology of PSDs. In this study, we have completed the identification of most major proteins in the PSD fraction with the use of an analytical method based on mass spectrometry coupled with searching of the protein sequence databases. At least one protein in each of 26 prominent protein bands from the PSD fraction has now been identified. We found 7 proteins not previously known to be constituents of the PSD fraction and 24 that had previously been associated with the PSD by other methods. The newly identified proteins include the heavy chain of myosin-Va (dilute myosin), a motor protein thought to be involved in vesicle trafficking, and the mammalian homolog of the yeast septin protein cdc10, which is important for bud formation in yeast. Both myosin-Va and cdc10 are threefold to fivefold enriched in the PSD fraction over brain homogenates. Immunocytochemical localization of myosin-Va in cultured hippocampal neurons shows that it partially colocalizes with PSD-95 at synapses and is also diffusely localized in cell bodies, dendrites, and axons. Cdc10 has a punctate distribution in cell bodies and dendrites, with some of the puncta colocalizing with PSD-95. The results support a role for myosin-Va in transport of materials into spines and for septins in the formation or maintenance of spines

    Wind-tunnel/flight correlation study of aerodynamic characteristics of a large flexible supersonic cruise airplane (XB-701) 2: Extrapolation of wind-tunnel data to full-scale conditions

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    The results of calculations necessary to extrapolate performance data on an XB-70-1 wind tunnel model to full scale at Mach numbers from 0.76 to 2.53 are presented. The extrapolation was part of a joint program to evaluate performance prediction techniques for large flexible supersonic airplanes similar to a supersonic transport. The extrapolation procedure included: interpolation of the wind tunnel data at the specific conditions of the flight test points; determination of the drag increments to be applied to the wind tunnel data, such as spillage drag, boundary layer trip drag, and skin friction increments; and estimates of the drag items not represented on the wind tunnel model, such as bypass doors, roughness, protuberances, and leakage drag. In addition, estimates of the effects of flexibility of the airplane were determined

    Sub-Planckian black holes and the Generalized Uncertainty Principle

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    The Black Hole Uncertainty Principle correspondence suggests that there could exist black holes with mass beneath the Planck scale but radius of order the Compton scale rather than Schwarzschild scale. We present a modified, self-dual Schwarzschild-like metric that reproduces desirable aspects of a variety of disparate models in the sub-Planckian limit, while remaining Schwarzschild in the large mass limit. The self-dual nature of this solution under MM1M \leftrightarrow M^{-1} naturally implies a Generalized Uncertainty Principle with the linear form Δx1Δp+Δp\Delta x \sim \frac{1}{\Delta p} + \Delta p. We also demonstrate a natural dimensional reduction feature, in that the gravitational radius and thermodynamics of sub-Planckian objects resemble that of (1+1)(1+1)-D gravity. The temperature of sub-Planckian black holes scales as MM rather than M1M^{-1} but the evaporation of those smaller than 103610^{-36}g is suppressed by the cosmic background radiation. This suggests that relics of this mass could provide the dark matter.Comment: 12 pages, 9 figures, version published in J. High En. Phy
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