64,723 research outputs found

    Observations of the gas stream in the mass transfer binary HR 2142 prime 1

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    The mass transfer binary system HR 2142 was observed at selected phases with the high resolution spectrograph on IUE. The observations were scheduled throughout the interval 0.91 phi 0.00 in order to allow viewing of the light of the primary star through the gas stream as it presents different orientations to the line of sight. Numerous UV lines formed in the gas stream were identified. The strengths and velocity variations displayed by these lines are compared with those observed in the ground based spectral region. As part of a preliminary analysis of the IUE data, column densities and velocities from Si III (4), Si IV (1), and Ti III (1) are used to deduce electron densities in the gas stream as well as its thickness. Possible evidence for stratification in the gas stream is presented

    A review of dynamic inflow and its effect on experimental correlations

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    A review is given of the relationship between experimental data and the development of modern dynamic-inflow theory. Some of the most interesting data, first presented 10 years ago at the Dynamic Specialist's Meeting, is now reviewed in light of the newer theories. These pure blade-flapping data correlate very well with analyses that include the new dynamic inflow theory, thus verifying the theory. Experimental data are also presented for damping with coupled inplane and body motions. Although inclusion of dynamic inflow is often required to correlate this coupled data, the data cannot be used to verify any particular dynamic inflow theory due to the uncertainties in modeling the inplane degree of freedom. For verification, pure flapping is required. However, the coupled data do show that inflow is often important in such computations

    Government and Social Media: A Case Study of 31 Informational World Cities

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    Social media platforms are increasingly being used by governments to foster user interaction. Particularly in cities with enhanced ICT infrastructures (i.e., Informational World Cities) and high internet penetration rates, social media platforms are valuable tools for reaching high numbers of citizens. This empirical investigation of 31 Informational World Cities will provide an overview of social media services used for governmental purposes, of their popularity among governments, and of their usage intensity in broadcasting information online.Comment: In Proceedings of the 47th Hawaii International Conference on System Sciences (pp. 1715-1724). IEEE Computer Society, 201

    Generalized (m,k)-Zipf law for fractional Brownian motion-like time series with or without effect of an additional linear trend

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    We have translated fractional Brownian motion (FBM) signals into a text based on two ''letters'', as if the signal fluctuations correspond to a constant stepsize random walk. We have applied the Zipf method to extract the ζ\zeta ' exponent relating the word frequency and its rank on a log-log plot. We have studied the variation of the Zipf exponent(s) giving the relationship between the frequency of occurrence of words of length m<8m<8 made of such two letters: ζ\zeta ' is varying as a power law in terms of mm. We have also searched how the ζ\zeta ' exponent of the Zipf law is influenced by a linear trend and the resulting effect of its slope. We can distinguish finite size effects, and results depending whether the starting FBM is persistent or not, i.e. depending on the FBM Hurst exponent HH. It seems then numerically proven that the Zipf exponent of a persistent signal is more influenced by the trend than that of an antipersistent signal. It appears that the conjectured law ζ=2H1\zeta ' = |2H-1| only holds near H=0.5H=0.5. We have also introduced considerations based on the notion of a {\it time dependent Zipf law} along the signal.Comment: 24 pages, 12 figures; to appear in Int. J. Modern Phys

    Human Factor Aspects of Traffic Safety

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    A new family, Coryphoridae (Ephemeroptera: Ephemerelloidea), and description of the winged and egg stages of Coryphorus

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    A new family Coryphoridae is proposed in the superfamily Ephemerelloidea for the monotypic genus Coryphorus. Characters that distinguish Coryphoridae from all other Ephemerelloidea are discussed. The male imago, male subimago, female imago, and egg of Coryphorus aquilus Peters are described for the first time.Se propone a Coryphoridae como una nueva familia de Ephemerelloidea para el genero monotipico Coryphorus. Se discuten los caracteres que distinguen a Coryphoridae del resto de los Ephemerelloidea. Se describen por primera vez el imago macho, subimago macho, imago hembra y huevo de Coryphorus aquilus Peters

    \u3cem\u3eLaunching through the Surf\u3c/em\u3e Traveling Exhibit Panel 10: Fiberglassing and Painting a Dory

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    Panel 10 documents the process of fiberglassing and painting (gelcoating) a new wooden dory. During the spring of 2012, project collaborator Tyrone Marshall photographed Pacific City glasser Jim Allen as he fiberglassed dory number 82, the Rehab.https://digitalcommons.linfield.edu/dory_exhibit/1009/thumbnail.jp

    Meteoritic ablation and fusion spherules in Antarctic ice

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    In the course of two Antarctic expeditions in 1980/1981 and 1982/1983 approximately 4 metric tons of documented ice samples were collected from the Atka Bay Ice Shelf, Antarctica, and subsequently shipped for cosmic dust studies. After filtration of the melt water, approximately 700 Antarctic spherules (AAS) in the size range of 5 to 500 microns were handpicked from the filter residue under optical microscopes. For the chemical investigation of single dust grains the following techniques were applied: scanning electron microscopy (SEM), X-ray analysis (EDAX), instrumental neutron activation analysis (INAA), laser microprobe mass analysis (LAMMA), and accelerator mass spectroscopy (AMS). For more than 95% of the total mass the bulk and trace elements were determined in single grain analyses using EDAX, INAA, and LAMMA. The element pattern of the dust particles was compared with that of typical terrestrial material and meteoritic matter. The majority of the spherules exhibited elemental compositions compatible with meteoritic element patterns
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