668 research outputs found

    External fuel vaporization study, phase 2

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    An analytical study was conducted to evaluate the effect of variations in fuel properties on the design of an external fuel vaporizaton system. The fuel properties that were considered included thermal stability, critical temperature, enthalpy a critical conditions, volatility, and viscosity. The design parameters that were evaluated included vaporizer weight and the impact on engine requirement such as maintenance, transient response, performance, and altitude relight. The baseline fuel properties were those of Jet A. The variation in thermal stability was taken as the thermal stability variation for Experimental Referee Broad Specification (ERBS) fuel. The results of the analysis indicate that a change in thermal stability equivalent to that of ERBS would increase the vaporization system weight by 20 percent, decrease oprating time between cleaning by 40 percent and make altitude relight more difficult. An increase in fuel critical temperature of 39 K would require a 40 percent increase in vaporization system weight. The assumed increase in enthalpy and volatility would also increase vaporizer weight by 40 percent and make altitude relight extremely difficult. The variation in fuel viscosity would have a negligible effect on the design parameters

    Initiating strategies in the sequential development of reading abilities for eighth grade students within a team-teaching structure (eighth grade unified: English and social studies team) at Starbuck Junior High - Racine, Wisconsin

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    The purpose of this research paper is to initiate change. In order to formulate reading in the total curriculum, polish learning tools, keep pace with the times, accept all students on equal terms, and continue to delve into the complexities of human development, the writer will become part of an eighth grade team. Developing reading skills in the content areas is best implemented from within the particular content area. Realistic planning and teaching is created when total participation is realized. Given the opportunity to become a member of the team, the writer will attempt strategies in the sequential development of reading abilities for eighth grade students within the framework of team decisions. The educational cycle of planning, teaching, and evaluation is a team process; therefore, reading skills will be formulated through team effort, implemented by team members, and evaluated by team members

    TOP-INDUCED ELECTROWEAK BREAKING IN THE MINIMAL SUPERSYMMETRIC STANDARD MODEL

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    Severe constraints on parameters of the minimal supersymmetric standard model follow from a dynamical electroweak symmetry breaking mechanism dominated by top and stop loops. In particular, the lightest Higgs boson mass is expected to be smaller than 100 GeV.Comment: 10 pages, Latex, 6 Postcript Figure

    HERA prospects on Compositeness and New Vector Bosons

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    The absence of deviations from the Standard Model for the differential cross section dσ/dQ2{d\sigma}/{dQ^2} at HERA is used to set limits on electron quark compositeness scale and on new vector bosons, especially the hadrophilic one recently introduced as a possible explanation for LEP/SLC and CDF anomalies.Comment: Latex file, 7 pages and 1 ps fig, few comments on others experiments are added, results are unchanged. To appear in Phys. Let.

    Modeling of premixing-prevaporizing fuel-air mixing passages

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    The development of a computer program for the analytical prediction of the distribution of liquid and vapor fuel in the premixing-prevaporizing passage by the direct injection method is described. The technical approach adopted for this program is to separate the problem into three parts each with its own computer code. These three parts are: calculation of the two-dimensional or axisymmetric air flow; calculation of the three-dimensional fuel droplet evaporation; and calculation of the fuel vapor diffusion. This method of approach is justified because premixing passages operate at lean equivalence ratios. Hence, a weak interaction assumption can be made wherein the airflow can affect the fuel droplet behavior but the fuel droplet behavior does not affect the airflow

    Analytical modeling of operating characteristics of premixing-prevaporizing fuel-air mixing passages. Volume 2: User's manual

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    A user's manual describing the operation of three computer codes (ADD code, PTRAK code, and VAPDIF code) is presented. The general features of the computer codes, the input/output formats, run streams, and sample input cases are described

    Improved version of the eikonal model for absorbing spherical particles

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    We present a new expression of the scattering amplitude, valid for spherical absorbing objects, which leads to an improved version of the eikonal method outside the diffraction region. Limitations of this method are discussed and numerical results are presented and compared successfully with the Mie theory.Comment: 7 pages, postscript figures available on cpt.univ-mrs.fr, to appear in J. Mod. Optic

    Detecting time-fragmented cache attacks against AES using Performance Monitoring Counters

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    Cache timing attacks use shared caches in multi-core processors as side channels to extract information from victim processes. These attacks are particularly dangerous in cloud infrastructures, in which the deployed countermeasures cause collateral effects in terms of performance loss and increase in energy consumption. We propose to monitor the victim process using an independent monitoring (detector) process, that continuously measures selected Performance Monitoring Counters (PMC) to detect the presence of an attack. Ad-hoc countermeasures can be applied only when such a risky situation arises. In our case, the victim process is the AES encryption algorithm and the attack is performed by means of random encryption requests. We demonstrate that PMCs are a feasible tool to detect the attack and that sampling PMCs at high frequencies is worse than sampling at lower frequencies in terms of detection capabilities, particularly when the attack is fragmented in time to try to be hidden from detection

    Glue constraining asymmetries in W, γ\gamma or Z production at CERN LHC

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    We propose a class of forward-backward asymmetries with respect to the subprocess c.m. scattering angle in VV+jet production at hadron colliders, with V being any of (W, Z, γ\gamma, H), which are directly proportional to the gluon distribution g(x)g(x). The informations that these asymmetries can provide are complementary of those reachable from measurements of the transverse momentum and/or the rapidity distributions of a VV in kinematical regimes where gluon scattering subprocesses dominate. The accuracy which can be reached in the W, Z and γ\gamma cases, at the upgraded Tevatron and at LHC, should allow a considerable improvement of our knowledge of the gluon distribution function, especially at large x.Comment: 20 pages including 14 figures. Minor corrections include
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