7,706 research outputs found
Convex Trace Functions on Quantum Channels and the Additivity Conjecture
We study a natural generalization of the additivity problem in quantum
information theory: given a pair of quantum channels, then what is the set of
convex trace functions that attain their maximum on unentangled inputs, if they
are applied to the corresponding output state?
We prove several results on the structure of the set of those convex
functions that are "additive" in this more general sense. In particular, we
show that all operator convex functions are additive for the Werner-Holevo
channel in 3x3 dimensions, which contains the well-known additivity results for
this channel as special cases.Comment: 9 pages, 1 figure. Published versio
Flutter parametric studies of cantilevered twin-engine transport type wing with and without winglet. Volume 2: Transonic and density effect investigations
Flutter characteristics of a cantilevered high aspect ratio wing with winglet were investigated. The configuration represented a current technology, twin engine airplane. Compressibility effects through transonic Mach numbers and a wide range of mass-density ratios were evaluated on a low speed and high speed model. Four flutter mechanisms were obtained from test, and analysis from various combinations of configuration parameters. It is shown that the coupling between wing tip vertical and chordwise motions have significant effect under some conditions. It is concluded that for the flutter model configurations studied, the winglet related flutter is amenable to the conventional flutter analysis techniques. The low speed model flutter and the high-speed model flutter results are described
Catalytic Conversion Probabilities for Bipartite Pure States
For two given bipartite-entangled pure states, an expression is obtained for
the least upper bound of conversion probabilities using catalysis. The
attainability of the upper bound can also be decided if that bound is less than
one.Comment: 4 pages; comments appreciated; the article is a modified version of
this preprint combined with arXiv:0707.044
Machine Foundations in Power Plant and Other Industries- Case Studies
Studies on dynamic behaviour of turbo-generator foundations of various ratings have been carried out. Salient response parameters have been identified, Field vibration measurements taken on a 200 MW T.G. foundation have been reported. Measurements taken under intermittent coast-up and constant speed conditions have been analysed using FFT analyser and the frequency response thus obtained has been presented and discussed. From the signature analysis, high vibration peaks associated with the soil vibration modes have been observed. Analytical study carried out for 200 MW TG foundation also indicated the significance of soil structure interaction effect on the dynamic response. Based on the results of the analytical and experimental studies, recommendations have been made to include the soil structure interaction effect for dynamic response calculations
Soil Structure Interaction Effects on the Response of 210 MW T.G. Frame Foundations
The Design Office practice for the analysis and design of frame foundation generally ignores the soil structure interaction effects on the response of the frame foundation. A 210 MW T.G. frame foundation is analyzed using various standard approaches as well as using 3-0 finite element analysis. The analysis is carried out for fixed base as well as for elastic base conditions. Linear and rotational soil springs are considered to include the effect of base elasticity. The results of the analysis are presented. The analysis reveals that the soil structure interaction effects are significant both on the dynamic response parameters as well as on the strength parameters
Effects of winglet on transonic flutter characteristics of a cantilevered twin-engine-transport wing model
A transonic model and a low-speed model were flutter tested in the Langley Transonic Dynamics Tunnel at Mach numbers up to 0.90. Transonic flutter boundaries were measured for 10 different model configurations, which included variations in wing fuel, nacelle pylon stiffness, and wingtip configuration. The winglet effects were evaluated by testing the transonic model, having a specific wing fuel and nacelle pylon stiffness, with each of three wingtips, a nonimal tip, a winglet, and a nominal tip ballasted to simulate the winglet mass. The addition of the winglet substantially reduced the flutter speed of the wing at transonic Mach numbers. The winglet effect was configuration-dependent and was primarily due to winglet aerodynamics rather than mass. Flutter analyses using modified strip-theory aerodynamics (experimentally weighted) correlated reasonably well with test results. The four transonic flutter mechanisms predicted by analysis were obtained experimentally. The analysis satisfactorily predicted the mass-density-ratio effects on subsonic flutter obtained using the low-speed model. Additional analyses were made to determine the flutter sensitivity to several parameters at transonic speeds
In search of principle: 70 years of gender jurisprudence in India
The largest democracy in the world – India – with over 1.3 billion people is home to about 660 million women and sexual minorities. Their lives are ridden with contradictions captured in dramatic, but nevertheless true, headlines which announce India as the world’s most dangerous country for women and at the same time affirm that India worships its women. Similarly, while hijras are celebrated as a unique community enriching India’s vibrant democracy, they remain severely discriminated against, facing exponential levels of violence on an everyday basis. The wider community of LGBTQIA+ people too remains vulnerable, facing routine discrimination including stereotyping, exclusion and violence despite proclamations of their equal citizenship by the Supreme Court in 2018...
High-fidelity simulation of an ultrasonic standing-wave thermoacoustic engine with bulk viscosity effects
We have carried out boundary-layer-resolved, unstructured fully-compressible
Navier--Stokes simulations of an ultrasonic standing-wave thermoacoustic engine
(TAE) model. The model is constructed as a quarter-wavelength engine,
approximately 4 mm by 4 mm in size and operating at 25 kHz, and comprises a
thermoacoustic stack and a coin-shaped cavity, a design inspired by Flitcroft
and Symko (2013). Thermal and viscous boundary layers (order of 10
m) are resolved. Vibrational and rotational molecular relaxation
are modeled with an effective bulk viscosity coefficient modifying the viscous
stress tensor. The effective bulk viscosity coefficient is estimated from the
difference between theoretical and semi-empirical attenuation curves.
Contributions to the effective bulk viscosity coefficient can be identified as
from vibrational and rotational molecular relaxation. The inclusion of the
coefficient captures acoustic absorption from infrasonic (10 Hz) to
ultrasonic (100 kHz) frequencies. The value of bulk viscosity depends on
pressure, temperature, and frequency, as well as the relative humidity of the
working fluid. Simulations of the TAE are carried out to the limit cycle, with
growth rates and limit-cycle amplitudes varying non-monotonically with the
magnitude of bulk viscosity, reaching a maximum for a relative humidity level
of 5%. A corresponding linear model with minor losses was developed; the linear
model overpredicts transient growth rate but gives an accurate estimate of
limit cycle behavior. An improved understanding of thermoacoustic energy
conversion in the ultrasonic regime based on a high-fidelity computational
framework will help to further improve the power density advantages of
small-scale thermoacoustic engines.Comment: 55th AIAA Aerospace Sciences Meeting, AIAA SciTech, 201
A computer program for automated flutter solution and matched point determination
The use of a digital computer program (MATCH) for automated determination of the flutter velocity and the matched-point flutter density is described. The program is based on the use of the modified Laguerre iteration formula to converge to a flutter crossing or a matched-point density. A general description of the computer program is included and the purpose of all subroutines used is stated. The input required by the program and various input options are detailed, and the output description is presented. The program can solve flutter equations formulated with up to 12 vibration modes and obtain flutter solutions for up to 10 air densities. The program usage is illustrated by a sample run, and the FORTRAN program listing is included
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