2,506 research outputs found
A study and an approach to historical performance practices in the French Baroque based on François Couperin\u27s Treiziéme Concert à 2 instrumens à L\u27unisson
The purpose of this document is to examine and explain historical performance practices as applicable to the Treiziéme Concert à 2 instrumens à L’unisson of Fran çois Couperin. It provides an in depth look at the written and unwritten traditions of tempo, articulation, phrasing, ornamentation, and the use of in égal. Meant as a guide for players of the modern bassoon, this monograph guides the reader through the aspects of performance practice listed above and their application to that instrument. This document contains an introductory chapter and a biographical chapter. The remaining chapters explain the components of historical performance practice that warrant consideration in the Treiziéme Concert à 2 instrumens à L’unisson. The final chapter serves as a preface to an edited version of the 13th concert. There are two appendices. The first appendix is a clean copy of the facsimile reprint, in modern notation, and the second appendix is an edited performing edition of the work. Both appendices were created with the Finale computer notation program
Analysis of on-orbit thermal characteristics of the 15-meter hoop/column antenna
In recent years, interest in large deployable space antennae has led to the development of the 15 meter hoop/column antenna. The thermal environment the antenna is expected to experience during orbit is examined and the temperature distributions leading to reflector surface distortion errors are determined. Two flight orientations corresponding to: (1) normal operation, and (2) use in a Shuttle-attached flight experiment are examined. A reduced element model was used to determine element temperatures at 16 orbit points for both flight orientations. The temperature ranged from a minimum of 188 K to a maximum of 326 K. Based on the element temperatures, orbit position leading to possible worst case surface distortions were determined, and the subsequent temperatures were used in a static finite element analysis to quantify surface control cord deflections. The predicted changes in the control cord lengths were in the submillimeter ranges
Locating the pseudogap closing point in cuprate superconductors: absence of entrant or reentrant behavior
Current descriptions of the pseudogap in underdoped cuprates envision a
doping-dependent transition line which descends monotonically towards
zero just beyond optimal doping. There is much debate as to the location of the
terminal point where vanishes, whether or not there is a phase
transition at and exactly how behaves below within the
superconducting dome. One perspective sees cutting the dome and
continuing to descend monotonically to zero at holes/Cu
referred to here as `entrant behavior'. Another perspective derived from
photoemission studies is that intersects the dome near holes/Cu then turns back below , falling to zero again
around referred to here as `reentrant behavior'. By
examining thermodynamic data for BiSrCaCuO we show
that neither entrant nor reentrant behavior is experimentally supported.
Rather, sharply delimits the pseudogap regime and for
the pseudogap is always present, independent of temperature. Similar
results are found for YCaBaCuO. For both
materials is not a temperature but a crossover scale, , reflecting instead the underlying pseudogap energy which
vanishes as .Comment: 20 Pages, 9 Figures, in press Phys. Rev.
Outstanding Educational Performance Awards: Highlighting High Achieving Arkansas Schools, 2010
So, in this Arkansas Education Report (AER) we aim to highlight excellent performance and give our congratulations. To that end, we are happy to highlight many high performing schools around the state in our now-annual AER entitled the Outstanding Educational Performance Awards
Lunar mining of oxygen using fluorine
Experiments during the first year of the project were directed towards generating elemental fluorine via the electrolysis of anhydrous molten fluorides. Na2SiF6 was dissolved in either molten NaBF4 or a eutectic (minimum-melting) mixture of KF-LiF-NaF and electrolyzed between 450 and 600 C to Si metal at the cathode and F2 gas at the anode. Ar gas was continuously passed through the system and F2 was trapped in a KBr furnace. Various anode and cathode materials were investigated. Despite many experimental difficulties, the capability of the process to produce elemental fluorine was demonstrated
On the angular momentum evolution of merged white dwarfs
We study the angular momentum evolution of binaries containing two white
dwarfs which merge and become cool helium-rich supergiants. Our object is to
compare predicted rotation velocities with observations of highly evolved stars
believed to have formed from such a merger, including RCrB and extreme helium
stars. The principal study involves a binary containing a 0.6 solar mass CO
white dwarf, and a 0.3 solar mass He white dwarf. The initial condition for the
angular momentum distribution is defined where the secondary fills its Roche
Lobe. We assume conservation of angular momentum to compute the angular
momentum distribution in a collisionless disk and subsequently in the giant
envelope. At the end of shell-helium burning, the giant contracts to form a
white dwarf. We derive the surface rotation velocity during this contraction.
The calculation is repeated for a range of initial mass ratios, and also for
the case of mergers between two helium white dwarfs; the latter will contract
to the helium main-sequence rather than the white dwarf sequence. Assuming
complete conservation of angular momentum, we predict acceptable angular
rotation rates for cool giants and during the initial subsequent contraction.
However such stars will only survive spin-up to reach the white dwarf sequence
(CO+He merger) if the initial mass ratio is close to unity. He+He merger
products must lose angular momentum in order to reach the helium main sequence.
Minimum observed rotation velocities in extreme helium stars are lower than our
predictions by at least one half, indicating that CO+He mergers must lose at
least one half of their angular momentum.Comment: 11 pages, 11 figures, MNRAS in pres
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