8,908 research outputs found
1D to 3D Crossover of a Spin-Imbalanced Fermi Gas
We have characterized the one-dimensional (1D) to three-dimensional (3D)
crossover of a two-component spin-imbalanced Fermi gas of 6-lithium atoms in a
2D optical lattice by varying the lattice tunneling and the interactions. The
gas phase separates, and we detect the phase boundaries using in situ imaging
of the inhomogeneous density profiles. The locations of the phases are inverted
in 1D as compared to 3D, thus providing a clear signature of the crossover. By
scaling the tunneling rate with respect to the pair binding energy, we observe
a collapse of the data to a universal crossover point at a scaled tunneling
value of 0.025(7).Comment: 5 pages, 4 figure
HRTEM study of a new non-stoichiometric BaTiO(3-δ) structure
BaTiO3-based multilayer ceramic capacitors (MLCCs) with Ni internal electrodes are co-fired in
reducing atmospheres to avoid oxidation of the electrode. Although dielectric materials are doped by
acceptor, donor and amphoteric dopants to minimize the oxygen vacancy content, there is still a
large concentration of oxygen vacancies that are accommodated in the BaTiO3 active layers. In
general, ABO3 perovskites demonstrates a strong ability to accommodate the oxygen vacancies and
maintain a regular pseudo-cubic structure. Oxygen deficient barium titanate can be transformed to a
hexagonal polymorph (h-BT) at high temperatures1,2. In this paper, we report the new modulated and
long range ordered structures of non-stoichiometric BaTiO3-δ that are observed in the electrically
degraded Ni-BaTiO3 MLCCs at low temperature
Turboprop cargo aircraft systems study
The effects of using advanced turboprop propulsion systems to reduce the fuel consumption and direct operating costs of cargo aircraft were studied, and the impact of these systems on aircraft noise and noise prints around a terminal area was determined. Parametric variations of aircraft and propeller characteristics were investigated to determine their effects on noiseprint areas, fuel consumption, and direct operating costs. From these results, three aircraft designs were selected and subjected to design refinements and sensitivity analyses. Three competitive turbofan aircraft were also defined from parametric studies to provide a basis for comparing the two types of propulsion
The Inclusive Semileptonic Decay Lepton Spectrum from
In this talk, we review the QCD calculation of the lepton spectrum from
inclusive semileptonic decay. We compare this prediction to that of the
ACCMM model. This latter work was done in collaboration with Csaba Csaki.Comment: MIT-CTP-2333, uses LATEX. Invited Talk, Presented at WHEPP-3 Workshop
in Madras,India, January, 199
Wave function of the radion in a brane world
We calculate the linearized metric perturbation corresponding to a massless
four-dimensional scalar field, the radion, in a five-dimensional two-brane
model of Randall and Sundrum. In this way we obtain relative strengths of the
radion couplings to matter residing on each of the branes. The results are in
agreement with the analysis of Garriga and Tanaka of gravitational and
Brans--Dicke forces between matter on the branes. We also introduce a model
with infinite fifth dimension and ``almost'' confined graviton, and calculate
the radion properties in that model.Comment: 5 pages revtex, no figures, equation correcte
Elliptic Phases: A Study of the Nonlinear Elasticity of Twist-Grain Boundaries
We develop an explicit and tractable representation of a twist-grain-boundary
phase of a smectic A liquid crystal. This allows us to calculate the
interaction energy between grain boundaries and the relative contributions from
the bending and compression deformations. We discuss the special stability of
the 90 degree grain boundaries and discuss the relation of this structure to
the Schwarz D surface.Comment: 4 pages, 2 figure
Springing for Student Textbooks? Exploring New Directions for Library Collections
Given the increasing costs of student textbooks, it is only natural that students would engage in cost-avoidance behaviors. Likewise, some professors have modified their curricular choices to avoid passing along the cost of required texts for their students. At the University of Tennessee Health Science Center, the library has licensed several databases that include access to a number of assigned student textbooks. While the provision of these textbooks was not the intent in the licensing of these resources, it is an added benefit of the subscription and their availability is appreciated by the students who may avoid individual purchases. Because there has been no effort on the part of the library to license resources for the purpose of providing access to textbooks, students in certain programs have access to many assigned texts while students in other programs have access to no textbooks at all.
Using an adapted version of a previously created survey, faculty were asked questions about currently licensed platforms, the selection of course textbooks, and the importance of textbook availability. The purpose of the survey was to gauge faculty members’ level of knowledge and interest in expanding the course textbook offerings available through the library’s electronic collections. Proposed future actions include expanding textbooks offerings, exploring potential funding streams to support the expansion, and involving librarians in curricular development and textbook selection
Turboprop Cargo Aircraft Systems study, phase 1
The effects of advanced propellers (propfan) on aircraft direct operating costs, fuel consumption, and noiseprints were determined. A comparison of three aircraft selected from the results with competitive turbofan aircraft shows that advanced turboprop aircraft offer these potential benefits, relative to advanced turbofan aircraft: 21 percent fuel saving, 26 percent higher fuel efficiency, 15 percent lower DOCs, and 25 percent shorter field lengths. Fuel consumption for the turboprop is nearly 40 percent less than for current commercial turbofan aircraft. Aircraft with both types of propulsion satisfy current federal noise regulations. Advanced turboprop aircraft have smaller noiseprints at 90 EPNdB than advanced turbofan aircraft, but large noiseprints at 70 and 80 EPNdB levels, which are usually suggested as quietness goals. Accelerated development of advanced turboprops is strongly recommended to permit early attainment of the potential fuel saving. Several areas of work are identified which may produce quieter turboprop aircraft
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