105,330 research outputs found
The development of aerodynamic uncertainties for the space shuttle orbiter
The Shuttle Program development schedule and the management decision to perform an orbital, manned mission on the first launch resulted in a requirement to develop realistic aerodynamic uncertainties for the preflight aerodynamic predictions. This paper addresses the methodology in developing two types of aerodynamic uncertainties. One involves the ability to reproduce aerodynamic results between various wind tunnel tests. The second addresses the difference between preflight aerodynamic predictions and flight results derived from analysis of past aircraft programs. Both types of uncertainties for pitching moment, lateral-directional stability, rudder power, and aileron power are presented. In addition, the application of uncertainties to flight control design and fight test planning is briefly reviewed
Are you a researcher as well as a medical illustrator?
When we list the areas of practice for medical illustrators we always include research, but how involved in research are we? The aim of this activity is to encourage your professional development not just as a medical illustrator but your involvement with research whether that is undertaking your own research, undertaking evidence based practice (1) , working as part of a research team, advising researchers on the value of medical illustration or supporting a student undertaking a research project for their degree or post-graduate qualification
Matching Excluded Volume Hadron Resonance Gas Models and Perturbative QCD to Lattice Calculations
We match three hadronic equations of state at low energy densities to a
perturbatively computed equation of state of quarks and gluons at high energy
densities. One of them includes all known hadrons treated as point particles,
which approximates attractive interactions among hadrons. The other two
include, in addition, repulsive interactions in the form of excluded volumes
occupied by the hadrons. A switching function is employed to make the crossover
transition from one phase to another without introducing a thermodynamic phase
transition. A chi-square fit to accurate lattice calculations with temperature
MeV determines the parameters. These parameters quantify the
behavior of the QCD running gauge coupling and the hard core radius of protons
and neutrons, which turns out to be fm. The most physically
reasonable models include the excluded volume effect. Not only do they include
the effects of attractive and repulsive interactions among hadrons, but they
also achieve better agreement with lattice QCD calculations of the equation of
state. The equations of state constructed in this paper do not result in a
phase transition, at least not for the temperatures and baryon chemical
potentials investigated. It remains to be seen how well these equations of
state will represent experimental data on high energy heavy ion collisions when
implemented in hydrodynamic simulations.Comment: 19 pages, 9 figure
Fixed-Base Simulator Studies of the Ability of the Human Pilot to Provide Energy Management Along Abort and Deep-Space Entry Trajectories
A simulation study has been made to determine a pilot's ability to control a low L/D vehicle to a desired point on the earth with initial conditions ranging from parabolic orbits to abort conditions along the boost phase of a deep-space mission. The program was conducted to develop procedures which would allow the pilot to perform the energy management functions required while avoiding the high deceleration or skipout region and to determine the information display required to aid the pilot in flying these procedures. The abort conditions studied extend from a region of relatively high flight-path angles at suborbital velocities while leaving the atmosphere to a region between orbital and near-escape velocity outside the atmosphere. The conditions studied included guidance from suborbital and superorbital aborts as well as guidance following return from a deepspace mission. In this paper, the role of the human pilot?s ability to combine safe return abort procedures with guidance procedures has been investigated. The range capability from various abort and entry conditions is also presented
Net Baryon Fluctuations from a Crossover Equation of State
We have constructed an equation of state which smoothly interpolates between
an excluded volume hadron resonance gas at low energy density to a plasma of
quarks and gluons at high energy density. This crossover equation of state
agrees very well with lattice calculations at both zero and nonzero baryon
chemical potential. We use it to compute the variance, skewness, and kurtosis
of fluctuations of baryon number, and compare to measurements of proton number
fluctuations in central Au-Au collisions as measured by the STAR collaboration
in a beam energy scan at the Relativistic Heavy Ion Collider. The crossover
equation of state can reproduce the data if the fluctuations are frozen out at
temperatures well below than the average chemical freeze-out.Comment: 5 pages, 7 figures. arXiv admin note: substantial text overlap with
arXiv:1506.0340
Review of the Supply of and Demand for Further Education in Scotland
These documents provide are an Executive Summary and Full Report of the background to, methodology for, and overall conclusions and recommendations of a review of the supply of and demand for Further Education (FE) provision in Scottish Further Education colleges in 2000. The review was commissioned by the Scottish Further Education Funding Council (SFEFC), and carried out between November 1999 and June 2000 by a team of researchers drawn from the Scottish Further Education Unit (SFEU), the Centre for Research in Lifelong Learning, Glasgow Caledonian University/University of Stirling, and the Applied Statistics Group, Napier University
Higher diversity of Rhizobium leguminosarum biovar viciae populations in arable soils than in grass soils
The bacterial genetic diversity after long-term arable cultivation was compared with that under permanent grassland using replicated paired contrasts, Pea-nodulating Rhizobium leguminosarum populations were sampled from pairs of arable and grass sites at four locations in Yorkshire, United Kingdom, isolates were characterized using both chromosomal (16S-23S ribosomal DNA internal transcribed spacer PCR-restriction fragment length polymorphism) and plasmid (group-specific repC PCR amplification) markers. The diversities of chromosomal types, repC profiles, and combined genotypes were calculated using richness in types (adjusted to equal sample sizes by rarefaction), Shannon-Wiener index, and Simpson's index. The relative differences in diversity within each pair of sites were similar for all three diversity measures, Chromosomal types, repC profiles, and combined genotypes were each more diverse in arable soils than in grass soils at two of the four locations. The other comparisons showed no significant differences. We conclude that rhizobial diversity can be affected by differences between these two management regimens. Multiple regression analyses indicated that lower diversity was associated with high potential nitrogen and phosphate levels or with acidity
Chiral extrapolations for nucleon magnetic moments
Lattice QCD simulations have made significant progress in the calculation of
nucleon electromagnetic form factors in the chiral regime in recent years. With
simulation results achieving pion masses of order ~180 MeV, there is an
apparent challenge as to how the physical regime is approached. By using
contemporary methods in chiral effective field theory, both the quark-mass and
finite-volume dependence of the isovector nucleon magnetic moment are carefully
examined. The extrapolation to the physical point yields a result that is
compatible with experiment, albeit with a combined statistical and systematic
uncertainty of 10%. The extrapolation shows a strong finite-volume dependence;
lattice sizes of L > 5 fm must be used to simulate results within 2% of the
infinite-volume result for the magnetic moment at the physical pion mass.Comment: 7 pages, 12 figures, 1 tabl
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