15,091 research outputs found

    The Boeing-Airbus “Can of Stink.” EUMA Papers, Vol. 5, No. 2 January 2008

    Get PDF
    The European Union and the United States have the largest trading relationship in the world, comprising about 60% of world trade (Perdikis and Read 267). They are also the greatest proponents of trade liberalization and multilateral trade cooperating in the world. Boeing was the undisputed king of aircraft manufacturing for most of the 20th century. Airbus has been encroaching upon that position since the 1970s. In 2000, Airbus dethroned Boeing in terms of sales, and the two have been in a bitter battle since. A subsidy dispute currently underway between Boeing (supported by the US) and Airbus (supported by the EU – mostly from Germany, England, France and Spain) could have devastating consequences upon that relationship and their credibility in promoting neoliberal values abroad. Most trade disputes are solved through consultation, without the need for a ruling by the World Trade Organization. Unlike most others, dispute regarding aircraft has elicited a special and unprecedented aggression on the part of these two trading partners

    A convergent expansion of the Airy's integral with incomplete Gamma functions

    Full text link
    There are two main power series for the Airy functions, namely the Maclaurin and the asymptotic expansions. The former converges for all finite values of the complex variable, zz, but it requires a large number of terms for large values of z|z|, and the latter is a Poincar\'{e}-type expansion which is well-suited for such large values and where optimal truncation is possible. The asymptotic series of the Airy function shows a classical example of the Stokes phenomenon where a type of discontinuity occurs for the homonymous multipliers. A new series expansion is presented here that stems from the method of steepest descents, as can the asymptotic series, but which is convergent for all values of the complex variable. It originates in the integration of uniformly convergent power series representing the integrand of the Airy's integral in different sections of the integration path. The new series expansion is not a power series and instead relies on the calculation of complete and incomplete Gamma functions. In this sense, it is related to the Hadamard expansions. It is an alternative expansion to the two main aforementioned power series that also offers some insight into the transition zone for the Stokes' multipliers due to the splitting of the integration path. Unlike the Hadamard series, it relies on only two different expansions, separated by a branch point, one of which is centered at infinity. The interest of the new series expansion is mainly a theoretical one in a twofold way. First of all, it shows how to convert an asymptotic series into a convergent one, even if the rate of convergence may be slow for small values of z|z|. Secondly, it sheds some light on the Stokes phenomenon for the Airy function by showing the transition of the integration paths at argz=±2π/3\arg z = \pm 2 \pi/3.Comment: 21 pages, 23 figures. Changes in version 2: i) Footnote 10 has been added, ii) Figure 5 has been added for a deeper analysis of the results, iii) Reference 15 has been added, iv) Typo: A ±\pm was missing in argz=±2π/3\arg z = \pm 2 \pi/3 (abstract), v) Some font size changes and improved labelling in the figures Changes in version 3: minor edition change

    Yield Management under the Real Options Scheme for Optimal Decision Making in Hotels

    Get PDF
    Yield management is the process of actively managing inventory to maximize revenues. In this paper we present a model demised to apply yield management techniques using real options to the problem of optimal decision making when assigning rooms to hotel customers. Two different methods are proposed to carry out the evaluation: numerical resolution with the PDEs and Monte Carlo simulation. The achieved results using both methods are similar demonstrating the robustness of the simulation in this field and the model lends itself to be a tool for helping the hotel manager in his operational decision of whether or not giving a room to a potential client

    Atmospheric refraction correction for Ka-band blind pointing on the DSS-13 beam waveguide antenna

    Get PDF
    An analysis of the atmospheric refraction corrections at the DSS-13 34-m diameter beam waveguide (BWG) antenna for the period Jul. - Dec. 1990 is presented. The current Deep Space Network (DSN) atmospheric refraction model and its sensitivity with respect to sensor accuracy are reviewed. Refraction corrections based on actual atmospheric parameters are compared with the DSS-13 station default corrections for the six-month period. Average blind-pointing improvement during the worst month would have amounted to 5 mdeg at 10 deg elevation using actual surface weather values. This would have resulted in an average gain improvement of 1.1 dB

    Study of photon emission by electron capture during solar nuclei acceleration. 2: Delimitation of conditions for charge transfert establishment

    Get PDF
    The conditions for establishment of charge transfer during acceleration of nuclei up to Fe, for typical conditions of solar flare regions T = 5 x 10 to the 3rd power to 2.5 x 10 to the 8th power degrees K were explored. Results show that such conditions are widely assorted, depending on the acceleration mechanism, the kind of projections and their velocity, the target elements, the source temperature and consequently on the degree of ionization of matter and the local charge state of the accelerated ions. Nevertheless, in spite of that assorted behavior, there are some general tendencies that can be summarized as follows. In atomic H electron capture is systematically established from thermal energies up to high energies, whatever the element and for both acceleration process. For a given element and fixed temperature (T), the probability and energy domain of electron capture and loss with Fermi are higher than with Betatron acceleration. For a given acceleration process the heavier the ion the higher the probability and the wider the energy range for electron capture and loss. For given acceleration mechanism and fixed element the importance and energy domain of capture and loss increase with T: for those reasons, the energy range of charge equilibrium (illustrated with solid lines on the next figs.) is wider with Fermi and increases with temperature and atomic number of projectiles. For the same reasons, electron loss is smaller while the lighter the element, the lower the temperature and the Betatron process, such that there are conditions for which electron loss is not allowed at low energies, but only electron capture is established

    Study of photon emission by electron capture during solar nuclei acceleration. 3: Photon production evaluations

    Get PDF
    Lower limits of photon fluxes were evaluated from electron capture during acceleration in solar flares, because the arbitrary q sub c asterisk assumed in this work evolves very slow with velocity, probably much more slowly than the physical actual situation: in fact, more emission is expected toward the IR region. Nevertheless the authors claim to show that the factibility of sounding acceleration processes, charge evolution processes and physical parameters of the source itself, by the observational analysis of this kind of emissions. For instance, it would be interesting to search observationally, for the predicted flux and energy drift of F sub e ions interacting with the atomic 0 and F sub e of the source matter, or, even more feasible for the X-ray lines at 4.2 keV and 2.624 + 0.003 KeV from Fe and S ions in ionized Fe at T = 10 to the 7th power K respectively, the 418 + or - 2 eV and 20 + or - 4 eV lines of Fe and S in ionized Fe at 5 x 10 to the 6th power K, which are predicted from Fermi acceleration

    Study of non-thermal photon production under different scenarios in solar flares. 1: Scenarios and formulations

    Get PDF
    In order to study the overall phenomenology involved in solar flares, it is necessary to understand their individual manifestation before building a corresponding description of the global phenomenon. Here the concern is with the production of X and gamma rays in solar flares. Flares are initiated very often within the closed magnetic field configurations of active centers. According (2) when beta = kinetic energy density/magnetic energy density approximately 0.2, the magnetic trap configuration is destructed within the time scale of the impulsive phase of flares ( 100 s). A first particle acceleration stage occurs during this phase as indicated by impulsive microwave and hard X-rays bursts. In some flare events, when the field strength beta is very high, the broken field lines may close again, such that later, in the course of the flash and main phases more hot plasma of very high conductivity is created, and so, the field and frozen plasma expand outward, as the kinetic pressure inside the closed loops increases. The magnetically trapped particles excite strong Alfven wave turbulence of small transverse scale

    Charged-Current Neutral Pion production at SciBooNE

    Full text link
    SciBooNE, located in the Booster Neutrino Beam at Fermilab, collected data from June 2007 to August 2008 to accurately measure muon neutrino and anti-neutrino cross sections on carbon below 1 GeV neutrino energy. SciBooNE is studying charged current interactions. Among them, neutral pion production interactions will be the focus of this poster. The experimental signature of neutrino-induced neutral pion production is constituted by two electromagnetic cascades initiated by the conversion of the neutral pion decay photons, with an additional muon in the final state for CC processes. In this poster, I will present how we reconstruct and select charged-current muon neutrino interactions producing neutral pions in SciBooNE.Comment: NuInt09 poster proceedings, 4 page
    corecore