Miracle-dz/UniFAR-FTUs huggingface dataset:
Two-layer model of shear-driven coastal upwelling in the presence of bottom topography

A stratified two-layer fluid is brought to solid-body counterclockwise rotation inside a cylindrical tank having a conical bottom with a radial topographic ridge. A stress is then applied to the top surface by means of a clockwise differentially rotating disk. The resulting Ekman-layer flux causes the top layer to spin-down and the interface to rise near the wall and to descend a t the centre of the tank. As this process continues, the interface (front) between the two layers intersects the disk surface, and after that migrates away from the wall and allows the bottom fluid to contact the disk directly. The migration of the front continues until a steady state is reached, the front becomes stationary and the system is in geostrophic balance. The first sign of upwelled flow at the surface always occurs as a high-speed jet-like plume at the bottom topography, and only at a later time does a uniform upwelled flow appear a t the surface upstream of the topography. This plume, which always forms near the downstream edge of the topography, migrates in advance of the upstream front to produce an upwelling maximum at the bottom topography. The final width of the upstream flow in steady-state conditions is estimated by a simple theoretical model, which is in good agreement with the experimental results. We have an experimental criterion to predict the occurrence of travelling baroclinic waves on the upstream front. On the downstream side of the ridge, large standing waves are observed, with significant upwelling within them. Under some circumstances cyclones pinch-off from the upstream front, the plume on the ridge and the crests of the large downstream standing waves. We present criteria to predict the occurrence of these pinch-off processes.
Hybrid‐mixed discretization of elasto‐dynamic contact problems using consistent singular mass matrices

An alternative spatial semi‐discretization of dynamic contact based on a modified Hamilton's principle is proposed. The modified Hamilton's principle uses displacement, velocity and momentum as variables, which allows their independent spatial discretization. Along with a local static condensation for velocity and momentum, it leads to an approach with a hybrid‐mixed consistent mass matrix. An attractive feature of such a formulation is the possibility to construct hybrid singular mass matrices with zero components at those nodes where contact is collocated. This improves numerical stability of the semi‐discrete problem: the differential index of the underlying differential‐algebraic system is reduced from 3 to 1, and spurious oscillations in the contact pressure, which are commonly reported for formulations with Lagrange multipliers, are significantly reduced. Results of numerical experiments for truss and Timoshenko beam elements are discussed. In addition, the properties of the novel discretization scheme for an unconstrained dynamic problem are assessed by a dispersion analysis.Copyright © 2013 John Wiley & Sons, Ltd.
FILTERING AND SMOOTHING IN STATE SPACE MODELS WITH PARTIALLY DIFFUSE INITIAL CONDITIONS

Ansley and Kohn (Annals of Statistics, 1985) generalized the Kalman filter to handle state space models with partially diffuse initial conditions and used this filter to compute the marginal likelihood of the observations efficiently. In this paper we simplify the algorithm and make it numerically more accurate and operationally more efficient. Based on this filtering algorithm we obtain a corresponding smoothing algorithm for the state vector.
TUNED SIMULATED ANNEALING BASED ON BOLTZMANN AND BOSE- EINSTEIN DISTRIBUTION APPLIED TO MAXSAT PROBLEM

In this paper, a hybrid Simulated Annealing algorithm using Boltzmann and Bose-Einstein Distributions (SABBE) is proposed. SABBE was designed for solving satisfiability (SAT) instances, and it has three phases: i) BP (Boltzmann Phase), ii) BEP (Bose-Einstein Phase), and iii) DEP (Dynamical Equilibrium Phase). BP and BEP are simulated annealing searching procedures based on Boltzmann and Bose-Einstein distributions respectively. BP ranges from high to low temperature values, while BEP goes from low to very low temperatures. Another simulated annealing search procedure, DEP, is applied at the final temperature of the second phase. However, DEP uses a particular heuristic for detection of stochastic equilibrium by employing a least squares method during its execution. Finally, SABBE parameters are tuned with an analytical method, which considers the maximal and minimal deterioration of SAT instances.
Wavelet Analysis of Simulated Tropical Convective Cloud Systems. Part II: Decomposition of Convective-Scale and Mesoscale Structure

Abstract Numerically simulated three-dimensional tropical convective systems were analyzed using a wavelet approach in which the vertical shear of the ambient wind is used as a decomposition criterion. The method objectively decomposes the simulated systems into their two primary components, namely organized deep convection and a mesoscale stratiform region. This reproduces the standard model of highly organized mesoscale convective systems as well as giving an objective characterization of less organized regimes. It demonstrates the vertical component of wind shear as a statistically useful criterion in addition to its better known role as a quasi-deterministic mechanism controlling the organization of convection and its scale selection.
On the evolution of accretion disc flow in cataclysmic variables – III. Outburst properties of constant and uniform-α model discs⋆

Attention is given to the stability and evolution of some simple accretion disk models in which the viscosity is prescribed by an ad hoc, uniform-alpha model. Emphasis is placed on systems in which the mass input rate from the secondary to the disk around the primary is assumed to be constant, although initial calculations with variable mass input rates are also performed. Time-dependent visual magnitude light curves constructed for cataclysmic binaries with a range of disk size, primary mass and mass input rate, and viscosity magnitude, are compared with the observed properties of various cataclysmic variable subclasses. The results obtained indicate that the observational differences between novae and dwarf novae may be due to mass input rate differences. The present models can reproduce the gross observational features of U-Gem-type dwarf nova outbursts.
Do High-Frequency Eddies Contribute to Low-Frequency Teleconnection Tendencies?*

Abstract An isentropic potential vorticity (PV) budget analysis is employed to examine the role of synoptic transients, advection, and nonconservative processes as forcings for the evolution of the low-frequency PV anomalies locally and those associated with the North Atlantic Oscillation (NAO) and the Pacific–North American (PNA) pattern. Specifically, the rate of change of the low-frequency PV is expressed as a sum of tendencies due to divergence of eddy transport, advection by the low-frequency flow (hereafter referred to as advection), and the residual nonconservative processes. The balance between the variances and covariances of these terms is illustrated using a novel vector representation. It is shown that for most locations, as well as for the PNA pattern, the PV variability is dominantly driven by advection. The eddy forcing explains a small amount of the tendency variance. For the NAO, the role of synoptic eddy fluxes is found to be stronger, explaining on average 15% of the NAO tendency varian.
Flow and mixing fields of turbulent bluff-body jets and flames

The mean structure of turbulent bluff-body jets and flames is presented. Measurements of the flow and mixing fields are compared with predictions made using standard turbulence models. It is found that two vortices exist in the recirculation zone; an outer vortex close to the air coflow and an inner vortex between the outer vortex and the jet. The inner vortex is found to shift downstream with increasing jet momentum flux relative to the coflow momentum flux and gradually loses its circulation pattern. The momentum flux ratio of the jet to the coflow in isothermal flows is found to be the only scaling parameter for the flow field structure. Three mixing layers are identified in the recirculation zone. Numerical simulations using the standard k-ϵ and Reynolds stress turbulence models underpredict the length of the recirculation zone. A simple modification to the C1 constant in the dissipation transport equation fixes this deficiency and gives better predictions of the flow and mixing fields. The mixed-is-b.
Arc exchange systems and renormalization

We exhibit the construction of stable arc exchange systems from the stable laminations of hyperbolic diffeomorphisms. We prove a one-to-one correspondence between (i) Lipshitz conjugacy classes of C 1+H stable arc exchange systems that are C 1+H fixed points of renormalization and (ii) Lipshitz conjugacy classes of C 1+H diffeomorphisms f with hyperbolic basic sets Λ that admit an invariant measure absolutely continuous with respect to the Hausdorff measure on Λ. Let HD s (Λ) and HD u (Λ) be, respectively, the Hausdorff dimension of the stable and unstable leaves intersected with the hyperbolic basic set Λ. If HD u (Λ) = 1, then the Lipschitz conjugacy is, in fact, a C 1+H conjugacy in (i) and (ii). We prove that if the stable arc exchange system is a fixed point of renormalization with bounded geometry, then the stable arc exchange system is smooth conjugate to an affine stable arc exchange system.
Electronic structure and transport properties in the transparent amorphous oxide semiconductor 2 CdO ⋅ GeO 2

An amorphous $2\mathrm{CdO}\ensuremath{\cdot}{\mathrm{GeO}}_{2}$ thin film with a band gap of 3.4 eV can be converted from an insulator (conductivity $\ensuremath{\sim}{10}^{\ensuremath{-}9}{\mathrm{S}\mathrm{}\mathrm{cm}}^{\ensuremath{-}1})$ into a degenerate semiconductor $(\ensuremath{\sim}{10}^{2}{\mathrm{S}\mathrm{}\mathrm{cm}}^{\ensuremath{-}1})$ by carrier doping with ion implantation without significant loss in visible transparency. An interesting feature of this material's transport property is its Hall mobility: a pn sign anomaly, which is commonly observed for amorphous semiconductors, is not seen. The estimated Hall mobility is \ensuremath{\sim}10 ${\mathrm{cm}}^{2}$ ${\mathrm{V}}^{\mathrm{\ensuremath{-}}1}$ ${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$, which is larger by several orders of magnitude than that of conventional amorphous semiconductors, and is comparable to that in the polycrystalline form. The electronic structure was investigated to understand these features through direct observation of the density of states (DOS) of the conduction band by inverse-photoelectron spectroscopy and molecular orbital calculation of the DOS for a model cluster justified by x-ray structural analysis combined with molecular dynamics and reverse Monte Carlo simulations. Although x-ray structural analysis revealed that disorder in the correlation between Cd-Cd ions was distinctly seen in the amorphous state, the DOS of the conduction band bottom was almost the same in the crystalline and amorphous states. Cluster calculations demonstrated that the bottom of the conduction band is primarily composed of Cd $5s$ orbitals. The characteristic transport properties in this material, such as large electron mobility, may be understood by considering that the magnitude of overlap between the $5s$ orbitals of neighboring ${\mathrm{Cd}}^{2+}$ is large and comparable to that in the crystal and insensitive to the structural randomness inherent to amorphous states.
Benchmark cases for outdoor sound propagation models

The computational tools available for prediction of sound propagation through the atmosphere have increased dramatically during the past decade. The numerical techniques include analytical solutions for selected index of refraction profiles, ray trace techniques which include interaction with a complex impedance boundary, a Gaussian beam ray trace algorithm, and more sophisticated approximate solutions to the full wave equation; the fast field program (FFP) and the parabolic equation (PE) solutions. This large aray of computational approaches raises questions concerning under what conditions the various approaches are reliable and concerns about possible errors in specific implementations. This paper presents comparisons of predictions from the several models assuming a complex impedance ground and four atmospheric conditions. For the cases studied, it was found that the FFP and PE algorithms agree to within numerical accuracy over the full range of conditions and agree with the analytical solutions where available. Comparisons to ray solutions define regimes where ray approaches can be used. There is no attempt to compare calculated transmission losses to measurements,
Lagrangian Coherent Structures

Typical fluid particle trajectories are sensitive to changes in their initial conditions. This makes the assessment of flow models and observations from individual tracer samples unreliable. Behind complex and sensitive tracer patterns, however, there exists a robust skeleton of material surfaces, Lagrangian coherent structures (LCSs), shaping those patterns. Free from the uncertainties of single trajectories, LCSs frame, quantify, and even forecast key aspects of material transport. Several diagnostic quantities have been proposed to visualize LCSs. More recent mathematical approaches identify LCSs precisely through their impact on fluid deformation. This review focuses on the latter developments, illustrating their applications to geophysical fluid dynamics.
Robust Antiwindup for Manual Flight Control of an Unstable Aircraft

A result on robust-in-the-large antiwindup compensation obtained for the case of asymptotically stable systems is extended to deal with unstable plants with asymptotically null references. The use of a weakened formulation of the antiwindup problem is crucial in the achievement of robustness to large parameter variations. The proposed design approach results in an antiwindup compensator that works as an add-on for any a priori given, high-performance controller, synthesized without taking saturation or robustness issues into account. The technique is applied to a reduced, short-period dynamic model of a highly unstable fighter aircraft, a case in which the issues of control saturation during aggressive maneuvering and robustness with respect to large parameter variations are of paramount importance. Simulations in low- and high-speed regimes demonstrate that the weakened antiwindup compensator outperforms previous antiwindup techniques in providing robust stability to the closed-loop system while exploiting the available control power in all of the considered maneuvers.
Gabor-based kernel PCA for palmprint recognition

A novel Gabor-based kernel principal component analysis (PCA) method by integrating the Gabor wavelet representation of palm images and the kernel PCA method for palmprint recognition is proposed. The feasibility of the proposed method has been successfully tested on two different public data sets from the PolyU palmprint databases, for which the samples were collected in two different sessions.
Equations in Scientific Proofs: Effects on Comprehension

Scientific laws are typically presented with corresponding proofs to justify their correctness and illustrate scientific reasoning. The form of these proofs is commonly a series of logically related equations. This research examined how this equation-based format influences proof comprehension. This was done by comparing learners’ ability to solve problems after studying typical equation-based proofs and matching proofs with equations replaced by verbal equivalents (a verbal format). Verbal proofs produced better performance than equation-based proofs on problems relating to both equations and nonequational proof content. These results suggest that equations in proofs cause learners to shift attention away from nonequational content and that learners have more difficulty processing equations than verbal statements containing the same content.
Self-assembly of thiophene/phenylene co-oligomers

Nanofibers from light-emitting organic molecules such as para-phenylenes have already demonstrated a promising application potential in nanophotonic devices and can act as waveguides or nanolasers. Here, the basic mechanisms for self-assembly of three different green- and green/blue-light emitting thiophene/phenylene co-oligomers into nanofibers are investigated. Under well defined conditions in high vacuum the molecules are deposited on cleaved mica surfaces. The effect of substrate surface energy as well as epitaxy on the overall film morphology is studied and significant differences between different co-oligomers are found.
The erosion and dispersal of massive molecular clouds by young stars

We evaluate the efficiency with which O stars disperse the molecular clouds from which they form. An O star near the surface of an extended molecular cloud ionizes a H II region which is radiation-bounded on the inner side (towards the cloud centre) and density-bounded on the outer side; consequently the ionized gas can stream away into space on the outer side, and this in turn enables the ionization front on the inner side to advance faster into the cloud, thus eroding a large cavity around the O star. This process may be very effective in destroying molecular clouds; if ∼ 4 per cent of a cloud&s material were converted into new stars with a Salpeter Initial Mass Function, the remaining 96 per cent could be broken up and dispersed by the ionizing radiation from the O stars
Reorganization of a two-dimensional disordered granular medium due to a small local cyclic perturbation

We measure experimentally the rearrangements due to a small localized cyclic displacement applied to a packing of rigid grains under gravity in a two-dimensional (2D) geometry. We analyse the evolution of the response to this perturbation by considering the individual particle displacement and the coarse-grained displacement field, as well as the mean packing fraction and coordination number. We find that the displacement response is rather long ranged, and evolves considerably with the number of cycles. We show that a small difference in the preparation method (induced by tapping the container) leads to a significant modification in the response though the packing fraction changes are minute. Not only the initial response but also its further evolution changes with preparation, demonstrating that the system still retains a memory of the initial preparation after many cycles. Nevertheless, after a sufficient number of cycles, the displacement response for both preparation methods converges to a nearly radial field with a 1/r decay from the perturbation source. The observed differences between the preparation methods seem to be related to the changes in the coordination number (which is more sensitive to the evolution of the packing than the packing fraction). Specifically, it may be understood as an effect of the breaking of local arches, which affects the lateral transmission of forces.
CLASSIFICATION OF INJECTIVE FACTORS

The fundamental results of A. Connes which determine a complete set of isomorphism classes for most injectlve factors are discussed in detail. After some introductory remarks which lay the foundation for the subsequent discussion, an historical survey of some of the principal lines of the investigation in the classification of factors is presented, culminating in the Connes-Takesakl structure theory of type III factors. After a discussion of inJectlvity for finite factors, the main result of the paper, the uniqueness of the injectlve II 1 factor, is deduced, and the structure of II. and type III injectlve factors is then obtained as corollaries of the main result. 1980 AMS (MOS) SUBJECT CLASSIFICATION: PRIMARY 46L35, 46LI0; SECONDARY- 46L50, 46L05 KEY WORI)S AND PHRASES: jiVe yon Nann o. %gebra, fi facr, dcre
The topology associated with cusp singular points

In this paper we investigate the global geometry associated with cusp singular points of two-degree of freedom completely integrable systems. It typically happens that such singular points appear in couples, connected by a curve of hyperbolic singular points. We show that such a couple gives rise to two possible topological types as base of the integrable torus bundle, that we call pleat and flap. When the topological type is a flap, the system can have non-trivial monodromy, and this is equivalent to the existence in phase space of a lens space compatible with the singular Lagrangian foliation associated to the completely integrable system.
Hierarchical distributed metamodel‐assisted evolutionary algorithms in shape optimization

In aerodynamic shape optimization, the availability of multiple evaluation models of different precision and hence computational cost can be efficiently exploited in a hierarchical evolutionary algorithm. Thus, in this work the demes of a distributed evolutionary algorithm are ordered in levels, with each level employing a different flow analysis method, giving rise to a hierarchical distributed scheme. The arduous task of exploring the design space is undertaken by demes consisting the lower hierarchy level, which use a low‐cost flow analysis tool, namely a viscous–inviscid flow interaction method. Promising solutions are directed towards the higher level, where these are further evolved based on a high precision/cost evaluation tool, viz. a Navier–Stokes equations solver. The final, optimal solution is obtained from the highest hierarchy level. At each level, metamodels, trained on‐line on the outcome of evaluations with the level's analysis tool, are used. The role of metamodels is to allow a parsimonious use of computational resources by filtering the poorly performing individuals in each deme. The entire algorithm has been implemented so as to take advantage of a parallel computing system. The efficiency and effectiveness of the proposed hierarchical distributed evolutionary algorithm have been assessed in the design of a transonic isolated airfoil and a compressor cascade. Remarkable superiority over the conventional evolutionary algorithms has been monitored. Copyright © 2006 John Wiley & Sons, Ltd.
Cross correlation between cosmic-ray fluctuations and interplanetary magnetic-field fluctuations

We present a study of the cross correlation between cosmic-ray intensity fluctuations and the interplanetary magnetic field, using the low-frequency limit of the theory of the interplanetary scintillations of cosmic rays. Cross-spectral analysis of the flux of the Alert neutron monitor and simultaneous values of the interplanetary magnetic field components are presented which support the theory. A model of cosmic-ray fluctuations is described, with effects of gradients and interplanetary sector structure dominating for very low frequencies (f ≲ 5×10−6Hz) and magnetic-field induced interplanetary scintillations of cosmic rays dominating for higher frequencies.