1,931 research outputs found
Definition of the 2005 flight deck environment
A detailed description of the functional requirements necessary to complete any normal commercial flight or to handle any plausible abnormal situation is provided. This analysis is enhanced with an examination of possible future developments and constraints in the areas of air traffic organization and flight deck technologies (including new devices and procedures) which may influence the design of 2005 flight decks. This study includes a discussion on the importance of a systematic approach to identifying and solving flight deck information management issues, and a description of how the present work can be utilized as part of this approach. While the intent of this study was to investigate issues surrounding information management in 2005-era supersonic commercial transports, this document may be applicable to any research endeavor related to future flight deck system design in either supersonic or subsonic airplane development
Efimov Trimer Formation via Ultracold Four-body Recombination
We discuss the collisional formation of Efimov trimers via ultracold
four-body recombination. In particular, we consider the reaction A+A+A+B->A3+B
with A and B ultracold atoms. We obtain expressions for the four-body
recombination rate and show that it reflects the three-body Efimov physics
either as a function of collision energy or as a function of the two-body
s-wave scattering length between A atoms. In addition, we briefly discuss
issues important for experimentally observing this interesting and relatively
unexplored process.Comment: 5 pages, 3 figure
Lifetime of molecule-atom mixtures near a Feshbach resonance in 40K
We report a dramatic magnetic field dependence in the lifetime of trapped,
ultracold diatomic molecules created through an s-wave Feshbach resonance in
40K. The molecule lifetime increases from less than 1 ms away from the Feshbach
resonance to greater than 100 ms near resonance. We also have measured the
trapped atom lifetime as a function of magnetic field near the Feshbach
resonance; we find that the atom loss is more pronounced on the side of the
resonance containing the molecular bound state
Vibration Analysis of Cracked Composite Plate
Composite materials are widely used in different arenas such as aircraft, naval and automobiles. Main motive behind that is the distinctive property of weight reduction, which is important for greater speeds, improved payloads and efficient fuel consumption. Various damages like cracks or delamination are inevitable during service period. They may be due to impact load, chemical decay or change in temperature or pressure conditions. It has been experimentally proved that confined damage in a structure causes the reduction in local structural stiffness, resulting in deviations in dynamic performance of the structure. Additional resonance or crack proliferation induce large displacements resulting in the failure of the structure. In this study, efforts have been made to determine the natural frequency of vibration of composite plate in different boundary conditions and the multiple parameters of crack have been varied and the results have been established. The tests on composite plate is done experimentally to find natural frequency using FFT analyser and the results are validated using ANSYS. The work is done with varying crack parameters like depth, length and orientation. The frequency decreases with increase in crack dimensions and decreases with increasing orientations. For different boundary conditions, frequency increases with decreasing degrees of freedom. This will help in designing structures resistant to earthquakes and other disasters, given that the resonance frequency is known earlier. It will help in building a safe structure and will prolong its life for many years
Fermi Condensates
Ultracold atomic gases have proven to be remarkable model systems for
exploring quantum mechanical phenomena. Experimental work on gases of fermionic
atoms in particular has seen large recent progress including the attainment of
so-called Fermi condensates. In this article we will discuss this recent
development and the unique control over interparticle interactions that made it
possible.Comment: Proceedings of ICAP-2004 (Rio de Janeiro). Review of Potassium
experiment at JILA, Boulder, C
Cooling a single atom in an optical tweezer to its quantum ground state
We report cooling of a single neutral atom to its three-dimensional
vibrational ground state in an optical tweezer. After employing Raman sideband
cooling for tens of milliseconds, we measure via sideband spectroscopy a
three-dimensional ground-state occupation of ~90%. We further observe coherent
control of the spin and motional state of the trapped atom. Our demonstration
shows that an optical tweezer, formed simply by a tightly focused beam of
light, creates sufficient confinement for efficient sideband cooling. This
source of ground-state neutral atoms will be instrumental in numerous quantum
simulation and logic applications that require a versatile platform for storing
and manipulating ultracold single neutral atoms. For example, these results
will improve current optical tweezer experiments studying atom-photon coupling
and Rydberg quantum logic gates, and could provide new opportunities such as
rapid production of single dipolar molecules or quantum simulation in tweezer
arrays.Comment: Updated intro, titl
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