41,831 research outputs found
NASTRAN static and buckling analysis - comparison with other large-capacity programs
A square plate with clamped edges under a concentrated load was modeled using NASTRAN and ASKA finite element computer programs. Deflections were computed for various width-to-thickness ratios (b/t) of the plate element, and were compared against the classical theory to determine the b/t limitations. A cylinder with simply supported ends was modeled using NASTRAN and STAGS computer programs for buckling analysis. The models were subjected to a uniform radial pressure loading. Several parameters were changed, and the effects of those variations are presented. Utilizing these data, a model which will produce results comparable to published empirical data can be constructed and processed for a minimized cost
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The Effect of Limited Attention and Delay on Negative Arousing False Memories
Previous research has shown that, in comparison to neutral stimuli, false memories for high arousing negative stimuli are greater after very fast presentation and limited attention at study. However, full compared to limited attention conditions still produce comparably more false memories for all stimuli types. Research has also shown that emotional stimuli benefit from a period of consolidation. What effect would such consolidation have on false memory formation even when attention is limited at study? The aim of the present study was to investigate the effect of fast presentation on false memory production for negatively-arousing and neutral items over time using the DRM paradigm. Sixty-Eight participants studied Negative and neutral DRM lists with fast or slow presentation conditions. Half completed a recognition test immediately and half completed a recognition test after one-week. Results revealed that, for fast presentation, negative critical lures increased after one week and were comparable to negative critical lures in the slow presentation encoding conditions. Neutral critical lures in the fast presentation condition did not change and remained lower compared to the slow presentation condition. These findings are the first demonstration that arousing negative false memories can increase over time when attention at encoding is limited
Entangling unitary gates on distant qubits with ancilla feedback
By using an ancilla qubit as a mediator, two distant qubits can undergo a
non-local entangling unitary operation. This is desirable for when attempting
to scale up or distribute quantum computation by combining fixed static local
sets of qubits with ballistic mediators. Using a model driven by measurements
on the ancilla, it is possible to generate a maximally entangling CZ gate while
only having access to a less entangling gate between the pair qubits and the
ancilla. However this results in a stochastic process of generating control
phase rotation gates where the expected time for success does not correlate
with the entangling power of the connection gate. We explore how one can use
feedback into the preparation and measurement parameters of the ancilla to
speed up the expected time to generate a CZ gate between a pair of separated
qubits and to leverage stronger coupling strengths for faster times.
Surprisingly, by choosing an appropriate strategy, control of a binary discrete
parameter achieves comparable speed up to full continuous control of all
degrees of freedom of the ancilla.Comment: 8 pages, 11 figure
A minimum control ancilla driven quantum computation scheme with repeat-until-success style gate generation
Some two qubit interactions are singly sufficient for universal quantum
computation but not without the use of an ancilla. Recent schemes for universal
quantum computation have focused on hybrid physical systems using ancillae. In
them, the application of resources is shifted to the ancilla system. We
consider which 2-qubit interactions are universal in ancilla schemes where
direct connections between main register qubits are forbidden. By the use of
ancilla driven operations and repeat-until-success style random gates, a single
fixed symmetric gate can be universal be control of the number of repetitions
alone
Gravity Dual of a Quantum Hall Plateau Transition
We show how to model the transition between distinct quantum Hall plateaus in
terms of D-branes in string theory. A low energy theory of 2+1 dimensional
fermions is obtained by considering the D3-D7 system, and the plateau
transition corresponds to moving the branes through one another. We study the
transition at strong coupling using gauge/gravity duality and the probe
approximation. Strong coupling leads to a novel kind of plateau transition: at
low temperatures the transition remains discontinuous due to the effects of
dynamical symmetry breaking and mass generation, and at high temperatures is
only partially smoothed out.Comment: 27 pages, 6 figures, harvmac; v2, references and minor comments
added, version to be submitted to JHEP; v3, corrections to section
Multispectral data restoration study
A digital resampling technique for LANDSAT data is reported that incorporates a deconvolution concept to minimize spatial and radiometric degradation of data during resampling for geometric correction. A quantitative comparison of cubic convolution and digital restoration methods establishes the latter as the superior technique
Dynamic analysis using superelements for a large helicopter model
Using superelements (substructures), modal and frequency response analysis was performed for a large model of the Advanced Attack Helicopter developed for the U.S. Army. Whiffletree concept was employed so that the residual structure along with the various superelements could be represented as beam-like structures for economical and accurate dynamic analysis. A very large DMAP alter to the rigid format was developed so that the modal analysis, the frequency response, and the strain energy in each component could be computed in the same run
Hydrogen transport in alpha titanium
Permeation experiments after nitriding the inlet surface of a hollow cylindrical membrane were conducted. Permeation data on two additional specimens given pre-oxidation or pre-nitriding treatments at both inlet and outlet surfaces are presented in terms of Arrhenius plots. Additionally, an analysis of geometry dependence on permeation rate was made for several specimens including the ones mentioned above. For simplicity in this report, the term as-polished is used to refer to a specimen which is either as-polished or is as-polished, pre-oxidized and annealed
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