10,390 research outputs found
Analytical and experimental study of the effects of wing-body aerodynamic interaction on space shuttle subsonic flutter
The effects on flutter of the aerodynamic interaction between the space shuttle bodies and wing, 1/80th-scale semispan models of the orbiter wing, the complete shuttle and intermediate component combinations were tested in the NASA Langley Research Center 26-inch Transonic Blowdown Wind Tunnel. Using the double lattice method combined with slender body theory to calculate unsteady aerodynamic forces, subsonic flutter speeds were computed for comparison. Using calculated complete vehicle modes, flutter speed trends were computed for the full scale vehicle at an altitude of 15,200 meters and a Mach number of 0.6. Consistent with findings of the model studies, analysis shows the shuttle to have the same flutter speed as an isolated cantilevered wing
SFitter: Reconstructing the MSSM Lagrangian from LHC data
Once supersymmetry is found at the LHC, the question arises what are the
fundamental parameters of the Lagrangian. The answer to this question should
thereby not be biased by assumptions on high-scale models. SFitter is a tool
designed for this task. Taking LHC (and possibly ILC) data as input it scans
the TeV-scale MSSM parameter space using its new weighted Markov chain
technique. Using this scan it determines a list of best-fitting parameter
points. Additionally a log-likelihood map is calculated, which can be reduced
to lower-dimensional Frequentist's profile likelihoods or Bayesian probability
maps.Comment: Submitted for the SUSY07 proceedings, 4 pages, LaTeX, 4 eps figure
The virtual observatory service TheoSSA: Establishing a database of synthetic stellar flux standards. I. NLTE spectral analysis of the DA-type white dwarf G 191-B2B
H-rich, DA-type white dwarfs are particularly suited as primary standard
stars for flux calibration. State-of-the-art NLTE models consider opacities of
species up to trans-iron elements and provide reliable synthetic
stellar-atmosphere spectra to compare with observation.
We establish a database of theoretical spectra of stellar flux standards that
are easily accessible via a web interface.
In the framework of the Virtual Observatory, the German Astrophysical Virtual
Observatory developed the registered service TheoSSA. It provides easy access
to stellar spectral energy distributions (SEDs) and is intended to ingest SEDs
calculated by any model-atmosphere code. In case of the DA white dwarf G
191-B2B, we demonstrate that the model reproduces not only its overall
continuum shape but also the numerous metal lines exhibited in its ultraviolet
spectrum.
TheoSSA is in operation and contains presently a variety of SEDs for DA white
dwarfs. It will be extended in the near future and can host SEDs of all primary
and secondary flux standards. The spectral analysis of G 191-B2B has shown that
our hydrostatic models reproduce the observations best at an effective
temperature of 60000 +/- 2000K and a surface gravity of log g = 7.60 +/- 0.05.
We newly identified Fe VI, Ni VI, and Zn IV lines. For the first time, we
determined the photospheric zinc abundance with a logarithmic mass fraction of
-4.89 (7.5 times solar). The abundances of He (upper limit), C, N, O, Al, Si,
O, P, S, Fe, Ni, Ge, and Sn were precisely determined. Upper abundance limits
of 10% solar were derived for Ti, Cr, Mn, and Co.
The TheoSSA database of theoretical SEDs of stellar flux standards guarantees
that the flux calibration of all astronomical data and cross-calibration
between different instruments can be based on the same models and SEDs
calculated with different model-atmosphere codes and are easy to compare.Comment: 42 pages, 27 figure
Di-boson Production beyond NLO QCD and Anomalous Couplings
In these proceedings, we review results for several di-boson production
processes beyond NLO QCD at high transverse momenta using the VBFNLO
Monte-Carlo program together with the LOOPSIM method. Additionally, we show for
the WZ production process how higher order QCD corrections can resemble
anomalous coupling effects.Comment: Conference Proceedings:C15-05-25.
Minimal Uncertainty in Momentum: The Effects of IR Gravity on Quantum Mechanics
The effects of the IR aspects of gravity on quantum mechanics is
investigated. At large distances where due to gravity the space-time is curved,
there appears nonzero minimal uncertainty in the momentum of a
quantum mechanical particle. We apply the minimal uncertainty momentum to some
quantum mechanical interferometry examples and show that the phase shift
depends on the area surrounded by the path of the test particle . We also put
some limits on the related parameters. This prediction may be tested through
future experiments. The assumption of minimal uncertainty in momentum can also
explain the anomalous excess of the mass of the Cooper pair in a rotating thin
superconductor ring.Comment: 8 pages, revised version accepted by PR
Body-freedom flutter of a 1/2-scale forward-swept-wing model, an experimental and analytical study
The aeroelastic phenomenon known as body-freedom flutter (BFF), a dynamic instability involving aircraft-pitch and wing-bending motions which, though rarely experienced on conventional vehicles, is characteristic of forward swept wing (FSW) aircraft was investigated. Testing was conducted in the Langley transonic dynamics tunnel on a flying, cable-mounted, 1/2-scale model of a FSW configuration with and without relaxed static stability (RSS). The BFF instability boundaries were found to occur at significantly lower airspeeds than those associated with aeroelastic wing divergence on the same model. For those cases with RSS, a canard-based stability augmentation system (SAS) was incorporated in the model. This SAS was designed using aerodynamic data measured during a preliminary tunnel test in which the model was attached to a force balance. Data from the subsequent flutter test indicated that BFF speed was not dependent on open-loop static margin but, rather, on the equivalent closed-loop dynamics provided by the SAS. Servo-aeroelastic stability analyses of the flying model were performed using a computer code known as SEAL and predicted the onset of BFF reasonably well
A re-analysis of the spectrum of 2206-199
Recently Pettini, Hunstead, Smith and Mar, (PHSM 1991) performed an analysis of the Ly-alpha forest of QSO 2206-199N at very high resolution. On the basis of their observations they concluded that most Doppler parameters b = (square root of 2)(sigma) of Ly-alpha forest lines are below 22 km/s, with a range down to a few km/s and a median of 17 km/s. They also found a strong intrinsic correlation between Doppler parameter b and column density N. These results are in contrast to those of a similar study by Carswell, Lanzetta, Parnell, and Webb (CLPW 1991) at comparable resolution with the same instruments, who find that most of the Ly-alpha lines towards QSO 1100-264 have Doppler parameters above 15 km/s (median b = 34 km/s), and that there is no significant correlation between b and N. Whilst an intrinsic difference between the lines of sight to 2206-199 and to other QSO's can not be excluded a priori, previous disagreement between Doppler parameter estimates obtained by both groups pointed to a potential difference in estimation techniques and in the interpretation of the results. To investigate this possibility, the AAT/UCLES spectrum of 2206-199 obtained by PHSM were reanalyzed. The spectrum was extracted from the raw data and determined the line parameters using the method described by CLPW
An Evidence-Based Practice Assessment and Quality Improvement Initiative in Idaho\u27s Critical Access Hospitals
Background: Health care providers and systems have been challenged to discard tradition-based care and outdated practices in lieu of evidence-based practice (EBP). Yet, little is known about the state of EBP, barriers and facilitators to EBP, and organizational readiness for EBP in Idaho’s Critical Access Hospitals (CAH). To affect positive change, it was necessary to understand whether providers in Idaho’s CAHs were using evidence as a foundation for practice—and, if not, what challenges existed in implementing EBP. Mitigating barriers and providing EBP education by way of webinar-based online technology has been proven to be practical and feasible. Providing EBP education, employing EBP tools and techniques, and implementing an evidence-based QI initiative will bridge the gap between knowledge and practice to improve health outcomes
Project Design: The aim of this project was to determine whether providers in Idaho’s CAH were using evidence as a foundation for practice. Nurse Executives (NE) from CAHs in the Northern region of Idaho answered questions about the state of evidence-based practice. One CAH volunteered to participate in an EBP continuing education program and complete a quality improvement initiative. Pre- and post-education intervention surveys were administered to measure the outcomes of this EBP continuing education program.
Results: The results of the NE needs assessment indicated NEs were familiar with EBP and were willing to participate in this project. Nurse executives reported they and their staffs wanted to learn more about EBP, they were interested in participating in an online modular EBP continuing education program, and they were willing to allocate a moderate amount of education dollars to fund this program. Additionally, they were engaged in EBP activities and interested in implementing EBP to address a specific quality issue in his or her organization. However, not all NEs were able to allocate education funds for clinicians to complete the 13-hour program or implement an interdisciplinary quality improvement initiative. The resulting hybrid modular EBP continuing education program was effective in improving mean scores for EBP competency, EBP beliefs, and EBP knowledge. After five months, mean scores demonstrated additional improvements in EBP competency, EBP beliefs, and EBP implementation.
Recommendations and Conclusions: Evidence-based practice improves patient care and quality outcomes. However, barriers exist and removing them can be a challenge for small and rural hospitals. The findings from this EBP assessment and quality improvement initiative demonstrate using an EBP nurse mentor to implement a hybrid modular EBP continuing education program is practical, feasible, and effective. With ongoing support from an EBP nurse mentor, interdisciplinary teams can employ EBP tools, processes, and resources to implement evidence-based quality improvement initiatives to improve patient outcomes. It is recommended this project be replicated in other CAHs in Idaho in partnership with Ohio State University’s Center for Transdisciplinary Evidence-Based Practice
Quantal interferometry with dissipative internal motion
In presence of dissipation, quantal states may acquire complex-valued phase
effects. We suggest a notion of dissipative interferometry that accommodates
this complex-valued structure and that may serve as a tool for analyzing the
effect of certain kinds of external influences on quantal interference. The
concept of mixed-state phase and concomitant gauge invariance is extended to
dissipative internal motion. The resulting complex-valued mixed-state
interference effects lead to well-known results in the unitary limit and in the
case of dissipative motion of pure quantal states. Dissipative interferometry
is applied to fault-tolerant geometric quantum computation.Comment: Slight revision, journal reference adde
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