668 research outputs found
External fuel vaporization study, phase 2
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
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
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
The absence of deviations from the Standard Model for the differential cross
section 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
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
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
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
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, or Z production at CERN LHC
We propose a class of forward-backward asymmetries with respect to the
subprocess c.m. scattering angle in +jet production at hadron colliders,
with V being any of (W, Z, , H), which are directly proportional to the
gluon distribution . 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 in kinematical regimes
where gluon scattering subprocesses dominate. The accuracy which can be reached
in the W, Z and 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
- …