490 research outputs found
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Automated Operations and Safety Data Collection and Usage in Contemporary Flight Operations Quality Audit Programs
Flight Operations Quality Audit (FOQA) programs are becoming more common to airlines of today. Flight data recording devices modified for repeated and daily data readouts have been dem-onstrating their unquestionable advantages in FOQA programmes. They demonstrate the interest of airlines, that use them, to transport people, cargo and mail in safe and efficient way. The paper will present general FOQA structure, historical developments in this field together with common obstacles when introducing FOQA to an airline. It also brings the latest data and understanding of benefits that FOQA has on airlines operation with potential applications of similar concepts to other means of transportation as well
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Different Automation Concepts in Civil Aircraft Cockpits of Today and Their Influence on Airline Flight Operations
Although there are different aircraft manufecturers and hence different practical solutions, there is one bottom line in automation. In aviation automation is only complement to humans. It is not present to challenge the pilot's role and responsibility. The use of new technologies and implementation of new functionality are dictated only by: significant safety benefits, obvious operational advantages, and clear response to the pilot's needs and operational factors influencing his functioning. The paper will discuss different approaches to automation related to flight operations in aviations. The paper intends to demonstrate how different manufacturers' approaches follows quite similar ideas in different automated system designs. The paper does not intend to give any final say when choosing one concept or the other. That is the matter of different circumstances requiring more justifying space and different criteria than the pure scientific one
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Flight Operations and Engineering Documentation Managing and Distribution Supported by Intelligent Transport Systems
Aviation as a multitude of activities is meant to satisfy needs of its customers to overcome distance and time between any departure and arrival point in the world. Airlines and other aircraft operators (governments, armed forces, general aviation, and business aviation) differ in their structure depending on their size and services they provide. Some departments are to be found in larger airlines only. However, core departments, to every airline or aircraft operator, are flight operations department and engineering department. Sophistication and the size of these departments depend on the size of the system they are incorporated in. Business logistics of an airline consist of numerous distinctive activities and functions. These activities have to be planned and completed in synchronisation. The paper presents an overview to intelligent systems for the support to these activities with particular stress on flight operations and maintenance functions in a medium sized airline. Authors show how the approach to documentation management, as a part of logistics in the production of transportation service, has evolved since the early 1990s when aviation has started to recognise the value of digital technical data. In light of this, authors analyse conceptual framework adopted by today's aircraft manufacturers towards their logistics activities supported by Internet as a new means of transferring data. The advent of new sophisticated pilot-machine interfaces and aircraft systems tends to increase the volume of the documentation describing these tools drastically. The paper communicates how operational documentation has to change to move towards a more easy and modern media. Intelligent systems that prove aviation entering a period where the "written book" is going to be complemented if not largely supplemented by the "electronic book" are presented from the early beginnings of digital data application to the most recent achievements
Discovery of a 270 Hz X-Ray Burst Oscillation in the X-Ray Dipper 4U 1916-053
We report the discovery of a highly coherent oscillation in a type-I X-ray
burst observed from 4U 1916-053 by the Rossi X-ray Timing Explorer (RXTE). The
oscillation was most strongly detected approx. 1 s after the burst onset at a
frequency of 269.3 Hz, and it increased in frequency over the following 4
seconds of the burst decay to a maximum of around 272 Hz. The total measured
drift of 3.58 +/- 0.41 Hz (1 sigma) represents the largest fractional change in
frequency (1.32 +/- 0.15 %) yet observed in any burst oscillation. If the
asymptotic frequency of the oscillation is interpreted in terms of a decoupled
surface burning layer, the implied neutron star spin period is around 3.7 ms.
However, the expansion of the burning layer required to explain frequency drift
during the burst is around 80 m, substantially larger than expected
theoretically (assuming rigid rotation). The oscillation was not present in the
persistent emission before the burst, nor in the initial rise. When detected
its amplitude was 6-12% (RMS) with a roughly sinusoidal profile. The burst
containing the oscillation showed no evidence for photospheric radius
expansion, while at least 5 of the other 9 bursts observed from the source by
RXTE during 1996 and 1998 did. No comparable oscillations were detected in the
other bursts. A pair of kilohertz quasi-periodic oscillations (QPOs) has been
previously reported from this source with a mean separation of 348 +/- 12 Hz.
4U 1916-053 is the first example of a source where the burst oscillation
frequency is significantly smaller than the frequency separation of the kHz
QPOs.Comment: 8 pages, 2 figures, 2 tables; accepted for ApJ Letter
Plane-wave impulse approximation extraction of the neutron magnetic form factor from quasielastic ^3He(e,e') at Q^2=0.3 to 0.6 (GeV/c)^2
A high precision measurement of the transverse spin-dependent asymmetry A_T' in ^3He(e,e') quasielastic
scattering was performed in Hall A at Jefferson Lab at values of the squared four-momentum transfer, Q^2,
between 0.1 and 0.6 (GeV/c)^2. A_(T') is sensitive to the neutron magnetic form factor, G_M^n . Values of G_M^n at
Q^2 = 0.1 and 0.2 (GeV/c)^2, extracted using Faddeev calculations, were reported previously. Here, we report
the extraction of G_M^n for the remaining Q^2 values in the range from 0.3 to 0.6 (GeV/c)^2 using a plane-wave
impulse approximation calculation. The results are in good agreement with recent precision data from experiments
using a deuterium target
Q^2 Evolution of the Neutron Spin Structure Moments using a ^3He Target
We have measured the spin structure functions g_1 and g_2 of ^3He in a double-spin experiment by inclusively scattering polarized electrons at energies ranging from 0.862 to 5.058 GeV off a polarized ^3He target at a 15.5° scattering angle. Excitation energies covered the resonance and the onset of the deep inelastic regions. We have determined for the first time the Q^2 evolution of Γ_1(Q^2)=∫_0^1g_1(x,Q^2)dx, Γ_2(Q^2)=∫_0^1g_2(x,Q^2)dx, and d_2(Q^2)=∫_0^1x^2[2g_1(x,Q^2)+3g_2(x,Q^2)]dx for the neutron in the range 0.1 ≤ Q^2 ≤0.9  GeV^2 with good precision. Γ_1(Q^2) displays a smooth variation from high to low Q^2. The Burkhardt-Cottingham sum rule holds within uncertainties and d_2 is nonzero over the measured range
Copper trafficking in eukaryotic systems: current knowledge from experimental and computational efforts
Copper plays a vital role in fundamental cellular functions, and its concentration in the cell must be tightly regulated, as dysfunction of copper homeostasis is linked to severe neurological diseases and cancer. This review provides a compendium of current knowledge regarding the mechanism of copper transfer from the blood system to the Golgi apparatus; this mechanism involves the copper transporter hCtr1, the metallochaperone Atox1, and the ATPases ATP7A/B. We discuss key insights regarding the structural and functional properties of the hCtr1-Atox1-ATP7B cycle, obtained from diverse studies relying on distinct yet complementary biophysical, biochemical, and computational methods. We further address the mechanistic aspects of the cycle that continue to remain elusive. These knowledge gaps must be filled in order to be able to harness our understanding of copper transfer to develop therapeutic approaches with the capacity to modulate copper metabolism
Precision Measurement of the Spin-Dependent Asymmetry in the Threshold Region of ^3He(e, e')
We present the first precision measurement of the spin-dependent asymmetry in the threshold region of ^3He(e,e′) at Q^2 values of 0.1 and 0.2(GeV/c)^2. The agreement between the data and nonrelativistic Faddeev calculations which include both final-state interactions and meson-exchange current effects is very good at Q^2 = 0.1(GeV/c)^2, while a small discrepancy at Q^2 = 0.2(GeV/c)^2 is observed
Q^2 Evolution of the Generalized Gerasimov-Drell-Hearn Integral for the Neutron using a ^3He Target
We present data on the inclusive scattering of polarized electrons from a polarized ^3He target at energies from 0.862 to 5.06 GeV, obtained at a scattering angle of 15.5°. Our data include measurements from the quasielastic peak, through the nucleon resonance region, and beyond, and were used to determine the virtual photon cross-section difference σ_(1/2)-σ_(3/2). We extract the extended Gerasimov-Drell-Hearn integral for the neutron in the range of four-momentum transfer squared Q^2 of 0.1–0.9   GeV^2
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