5,560 research outputs found
Unsteady adjoint of pressure loss for a fundamental transonic turbine vane
High fidelity simulations, e.g., large eddy simulation are often needed for
accurately predicting pressure losses due to wake mixing in turbomachinery
applications. An unsteady adjoint of such high fidelity simulations is useful
for design optimization in these aerodynamic applications. In this paper we
present unsteady adjoint solutions using a large eddy simulation model for a
vane from VKI using aerothermal objectives. The unsteady adjoint method is
effective in capturing the gradient for a short time interval aerothermal
objective, whereas the method provides diverging gradients for long
time-averaged thermal objectives. As the boundary layer on the suction side
near the trailing edge of the vane is turbulent, it poses a challenge for the
adjoint solver. The chaotic dynamics cause the adjoint solution to diverge
exponentially from the trailing edge region when solved backwards in time. This
results in the corruption of the sensitivities obtained from the adjoint
solutions. An energy analysis of the unsteady compressible Navier-Stokes
adjoint equations indicates that adding artificial viscosity to the adjoint
equations can potentially dissipate the adjoint energy while potentially
maintain the accuracy of the adjoint sensitivities. Analyzing the growth term
of the adjoint energy provides a metric for identifying the regions in the flow
where the adjoint term is diverging. Results for the vane from simulations
performed on the Titan supercomputer are demonstrated.Comment: ASME Turbo Expo 201
Detection of N-particle entanglement with generalized Bell inequalities
We show that the generalized Bell-type inequality, explicitly involving
rotational symmetry of physical laws, is very efficient in distinguishing
between true N-particle quantum correlations and correlations involving less
particles. This applies to various types of generalized partial separabilities.
We also give a rigorous proof that the new Bell inequalities are maximally
violated by the GHZ states, and find a very handy description of the N-qubit
correlation function.Comment: 5 pages, minor typos corrected, journal versio
Multiparticle Bell's inequalities involving many measurement settings
We present a prescription for obtaining Bell's inequalities for N>2 observers
involving more than two alternative measurement settings. We give examples of
some families of such inequalities. The inequalities are violated by certain
classes of states for which all standard Bell's inequalities with two
measurement settings per observer are satisfied.Comment: 4 pages, RevTeX
A Two-Coordinate Nickel Imido Complex That Effects C−H Amination
An exceptionally low coordinate nickel imido complex, (IPr*)Ni═N(dmp) (2) (dmp = 2,6-dimesitylphenyl), has been prepared by the elimination of N_2 from a bulky aryl azide in its reaction with (IPr*)Ni(η^6-C_7H_8) (1). The solid-state structure of 2 features two-coordinate nickel with a linear C−Ni−N core and a short Ni−N distance, both indicative of multiple-bond character. Computational studies using density functional theory showed a Ni═N bond dominated by Ni(dπ)−N(pπ) interactions, resulting in two nearly degenerate singly occupied molecular orbitals (SOMOs) that are Ni−N π* in character. Reaction of 2 with CO resulted in nitrene-group transfer to form (dmp)NCO and (IPr*)Ni(CO)_3 (3). Net C−H insertion was observed in the reaction of 2 with ethene, forming the vinylamine (dmp)NH(CH═CH_2) (5) via an azanickelacyclobutane intermediate, (IPr*)Ni{N,C:κ^2-N(dmp)CH_2CH_2} (4)
Yeah, Right, Uh-Huh: A Deep Learning Backchannel Predictor
Using supporting backchannel (BC) cues can make human-computer interaction
more social. BCs provide a feedback from the listener to the speaker indicating
to the speaker that he is still listened to. BCs can be expressed in different
ways, depending on the modality of the interaction, for example as gestures or
acoustic cues. In this work, we only considered acoustic cues. We are proposing
an approach towards detecting BC opportunities based on acoustic input features
like power and pitch. While other works in the field rely on the use of a
hand-written rule set or specialized features, we made use of artificial neural
networks. They are capable of deriving higher order features from input
features themselves. In our setup, we first used a fully connected feed-forward
network to establish an updated baseline in comparison to our previously
proposed setup. We also extended this setup by the use of Long Short-Term
Memory (LSTM) networks which have shown to outperform feed-forward based setups
on various tasks. Our best system achieved an F1-Score of 0.37 using power and
pitch features. Adding linguistic information using word2vec, the score
increased to 0.39
Rotational invariance as an additional constraint on local realism
Rotational invariance of physical laws is a generally accepted principle. We
show that it leads to an additional external constraint on local realistic
models of physical phenomena involving measurements of multiparticle spin 1/2
correlations. This new constraint rules out such models even in some situations
in which standard Bell inequalities allow for explicit construction of such
models. The whole analysis is performed without any additional assumptions on
the form of local realistic models.Comment: 4 page
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