Miracle-dz/UniFAR-FTUs huggingface dataset:
The motion of buoyant elements in turbulent surroundings

In this paper a theoretical model of the motion of isolated buoyant elements in turbulent surroundings is introduced, which takes into account both the growth due to turbulent entrainment and a loss of buoyant fluid to the environment. On dimensional grounds the outflow velocity is taken to be constant and proportional to some characteristic turbulent velocity in the environment, while the entrainment velocity is proportional to the upward velocity of the element. Numerical solutions of the resulting non-dimensional equations of motion are presented, corresponding to a wide range of stabilities. Typically, an element in stable, neutral or moderately unstable surroundings at first grows and then is eroded away, but at a certain value of a stability parameter γ elements become absolutely unstable and continue to grow and rise indefinitely. The value of γ is extremely sensitive to the level of turbulence in the environment, which could therefore exert a controlling influence on the growth of buoyant elements in unstable conditions; large elements are more likely to grow when the level of turbulence is low. Laboratory experiments have been carried out in order to test one of the predictions of this theory, the form of the dependence of the height attained on total buoyancy and level of turbulence in uniform surroundings. The agreement is good, and numerical comparison of theory and experiment suggests that the assumed outflow velocity is of the same order as, but somewhat less than, the r.m.s. turbulent velocity.
Regulation of Plasminogen Activator Inhibitor-1 mRNA in Human Endothelial Cells

Summary The plasminogen activator inhibitor (PAI-1) from endothelial cells is a potentially important regulator of plasminogen activator activity. Cultured human endothelial cells increase their PAI-1 production upon stimulation with LPS and TNF, agents that are known to cause an increase in PAI-1 levels in vivo. We isolated a PAI-1 cDNA probe, and by RNA hybridization analysis studied the regulation of PAI-1 mRNA synthesis in human endothelial artery cells. Freshly isolated endothelial cells do not contain detectable amounts of PAI-1 mRNA, but after adherence and incubation for 18 h in growth medium produce considerable amounts of PAI-1 activity and contain PAI-1 mRNA levels comparable to those found in subcultured cells. When subcultured endothelial cells are incubated for 6 h with LPS or TNF, both species of PAI-1 mRNA increase 10 to 20 fold, while PAI-1 activity in the growth medium increases only 1.5 to 2 fold. Stimulation of endothelial cells in the presence of cycloheximide (CHX) results in superinduction of mainly the 3.0 kb PAI-1 mRNA. The 3' end of this mRNA contains a 60 bp AT-rich sequence, that resembles 3' sequences present in a number of other genes superinducible with CHX.
Comparison of the cosine and Fourier transforms of Markov-1 signals

This correspondence compares the effectiveness of the discrete cosine and Fourier transforms in decorrelating sampled signals with Markov-1 statistics. It is shown that the discrete cosine transform (DCT) offers a higher (or equal) effectiveness than the discrete Fourier transform (DFT) for all values of the correlation coefficient. The mean residual correlation is shown to vanish as the inverse square root of the sample size.
Dust and molecular content of the lensed quasar, MG0751+2716, at z = 3.2

Context. Gravitational lenses offer unique opportunities to explore the molecular content around active galactic nuclei at high redshift, through the magnification and gain in angular resolution. Aims. We study here the molecular and dust content of the high redshift ($z=3.2$), gravitationally lensed quasar MG0751+2716. Methods. We used the IRAM Plateau de Bure interferometer to measure the CO $J=3{-}2$, $J=4{-}3$ and $J=8{-}7$ rotation lines and continuum flux between 1.1 mm and 3 mm in MG0751+2716. We use HST data and constraints from the high resolution MERLIN map at 6.2 cm to build an improved model of the lens. Results. The position agreement between the CO emission and the millimeter continuum suggests that dust and molecules are closely related. A 500 $\,{\rm km~s}^{-1}$ velocity gradient is tentatively detected from the CO lines across the central 0.5″. The continuum SED in the range 0.45 mm–204 mm exhibits the signatures of two components: synchrotron emission from a core/jet system, and thermal emission related to warm dust. The CO line intensities are compatible with warm, dense molecular gas, suggesting a location in the close environment of the quasar. These observational constraints lead us to consider a source/quasar model made of a point-like core, a radio jet, and a molecular and dusty ring-like structure (~460 pc in radius) located in a plane perpendicular to the jet axis and seen almost edge-on. For this configuration, we derive a total magnification of 16 for the quasar radiation at rest frequency above 350 GHz and a magnification of 25 below 350 GHz. The dust mass (assuming a likely temperature $T=50$ K) is $M_{\rm dust}=1.7 \times 10^8$ $M_\odot$, the mass of molecular material is $M({\rm H}_2) = 6 \times 10^{10}$ $M_\odot$ and a lower limit to the dynamical mass is $M_{\rm dyn} = 1.5 \times 10^{10}$ $M_\odot$. Such values are comparable to those found in the small sample of CO detected sources at high redshifts.
CCD Imagery of Planetary Nuclei: The Properties of the Central Stars of NGC 2440 and NGC 7027

Les observations spectrophotometriques et l'imagerie CCD des etoiles centrales des nebuleuses planetaires NGC 2440 et NGC 7027 sont presentees. La magnitude absolue, la luminosite, le rayon, la temperature effective et la masse de ces etoiles sont determines
A Crossed Random Effects Model for Unbalanced Data With Applications in Cross-Sectional and Longitudinal Research

Hierarchical linear models have found widespread application when the data have a nested structure—for example, when students are nested within classrooms (a two-level nested structure) or students are nested within classrooms and classrooms are nested within schools (a three-level nested structure). Often, however, the data will have a more complex nested structure. In Example 1, students are nested within both neighborhoods and schools; however, a school can draw students from multiple neighborhoods, and a neighborhood can send students to multiple schools. In Example 2, children are nested within classrooms during the first year of the study; however, each child finds himself or herself with a new teacher and a new set of classmates during each subsequent year of the study. By combining Lindley and Smith’s (1972) concepts of exchangeability between and within regressions, this article formulates a crossed random effects model that applies to such data, provides maximum likelihood estimates via the EM algorithm, and illustrates application to study (a) neighborhood and school effects on educational attainment in Scotland and (b) classroom effects on mathematics learning during the primary years in the United States.
Theory and computation of disturbance invariant sets for discrete-time linear systems

This paper considers the characterization and computation of invariant sets for discrete-time, time-invariant, linear systems with disturbance inputs whose values are confined to a specified compact set but are otherwise unknown. The emphasis is on determining maximal disturbance-invariant sets X that belong to a specified subset Γ of the state space. Such d-invariant sets have important applications in control problems where there are pointwise-in-time state constraints of the form χ(t)∈Γ . One purpose of the paper is to unite and extend in a rigorous way disparate results from the prior literature. In addition there are entirely new results. Specific contributions include: exploitation of the Pontryagin set difference to clarify conceptual matters and simplify mathematical developments, special properties of maximal invariant sets and conditions for their finite determination, algorithms for generating concrete representations of maximal invariant sets, practical computational questions, extension of the main results to general Lyapunov stable systems, applications of the computational techniques to the bounding of state and output response. Results on Lyapunov stable systems are applied to the implementation of a logic-based, nonlinear multimode regulator. For plants with disturbance inputs and state-control constraints it enlarges the constraint-admissible domain of attraction. Numerical examples illustrate the various theoretical and computational results.
Existence and Comparison Results for Difference φ-Laplacian Boundary Value Problems with Lower and Upper Solutions in Reverse Order

Abstract This paper is devoted to the study of the existence and comparison results for nonlinear difference φ-Laplacian problems with mixed, Dirichlet, Neumann, and periodic boundary value conditions. We deduce existence of extremal solutions of periodic and Neumann boundary value problems lying between a pair of lower and upper solutions given in reverse order. We prove the optimality of some assumptions in φ.
FEM calculation of rotor losses in a medium speed direct torque controlled PM synchronous motor at different load conditions

Summary form only given. In direct torque control (DTC), the switching frequency of the converter is not constant but it varies according to optimal switching condition. For example, when driving a permanent magnet synchronous motor at no load operation, the bandwidth of the switching frequency can be several kHz which cause high distortion of stator currents and, therefore, increase in rotor losses. In this work rotor losses of a medium speed permanent magnet synchronous motor driven by a direct torque controlled electrical drive were calculated using 2D time-stepping finite element method coupled with the motion equation. Circuit equations were used in the model in order to take the effects of the distorted phase currents into account. Calculations were performed at different load conditions.
Surface plasmon polaritons in attenuated total reflection systems with metamaterials: homogeneous problem

In this work we study the propagation characteristics of surface plasmon polaritons (surface eigenmodes) of Kretschmann attenuated total reflection structures with metamaterials. Contrary to the conventional case, in which surface polaritons with positive phase velocity appear at the boundary of a metallic guide, we consider a case where surface polaritons propagate along the boundary of a transparent metamaterial guide with negative refractive index. Depending on the choice of the metamaterial constitutive parameters, these polaritons can have either positive (forward) or negative (backward) phase velocity. For both situations we show numerical examples that illustrate the variation of the real and imaginary parts of the propagation constant with the guide width and the spatial distributions of energy.
On the regular and the asymptotic characteristic initial value problem for Einstein’s vacuum field equations

The regular characteristic initial value problem for Einstein’s vacuum field equations where data are given on two intersecting null hypersurfaces is reduced to a characteristic initial value problem for a symmetric hyperbolic system of differential equations. This is achieved by making use of the spin-frame formalism instead of the harmonic gauge condition. The method is applied to the asymptotic characteristic initial value problem for Einstein’s vacuum field equations, where data are given on part of past null infinity and on an incoming null-hypersurface. A uniqueness theorem for this problem is proved by showing that a solution of the problem must satisfy a regular symmetric hyperbolic system of differential equations in a neighbourhood of past null infinity.
The Impact of Horizontal Model Grid Resolution on the Boundary Layer Structure over an Idealized Valley

AbstractThe role of horizontal model grid resolution on the development of the daytime boundary layer over mountainous terrain is studied. A simple idealized valley topography with a cross-valley width of 20 km, a valley depth of 1.5 km, and a constant surface heat flux forcing is used to generate upslope flows in a warming valley boundary layer. The goal of this study is to investigate differences in the boundary layer structure of the valley when its topography is either fully resolved, smoothed, or not resolved by the numerical model. This is done by performing both large-eddy (LES) and kilometer-scale simulations with horizontal mesh sizes of 50, 1000, 2000, 4000, 5000, and 10 000 m. In LES mode a valley inversion layer develops, which separates two vertically stacked circulation cells in an upper and lower boundary layer. These structures weaken with decreasing horizontal model grid resolution and change to a convective boundary layer over an elevated plain when the valley is no longer resolved. Mean.
SH: A Novel Method for the Dynamic and Shortest Path Problem

For the dynamic and shortest path problem, a novel algorithm SH(simulate human) is designed by simulating the process of our searching path in real life. The algorithm adopts the idea of heuristic search and integrates with the ant colony algorithm, in which the saved current path, the idea of “ask once every junction”, the bypassing barrier search and other some related definitions are proposed, as well as the ant colony algorithm is improved, so as to find the better solution and reduce the searching time. The experimental results show that the algorithm runs better than other existing methods. Moreover, it can find the shortest path or the approximate shortest one in a shorter time on road networks of any scales. Especially, SH algorithm is more effective for the large scale road network.
A multiscale model for anisotropic damage and hysteresis in biodegradable polymers

Abstract. Predicting the mechanical response of biological soft materials requires an understanding of the complex phenomena characterizing their microscale. In this work, we use an existing versatile framework, based on assumptions on the statistical distribution of biolpolymers at the network scale, for extending our previous entropic constitutive model of Worm-Like Chains networks to different deformation classes. Furthermore, we include the effect of molecules topological constraints by introducing an energy term depending on the second invariant of the Green-Cauchy tensor. In this way we are able to qualitatively reproduce, with a limited set of physically meaningful constitutive parameters, a range of observed phenomena such as induced anisotropy, stress softening, hardening, Mullins effect, evolution of permanent stretches.
Nonlinear optimal control: alternatives to Hamilton-Jacobi equation

The methods of frozen Riccati equations and nonlinear matrix inequalities (NLMIs) offer certain computational advantages over Hamilton-Jacobi equations (HJE), but may fail to be optimal. The frozen Riccati method uses a non-unique state-dependent linear representation to reduce the HJE to a state-dependent Riccati equation. While there usually exists some choices that recover the optimality, it may be difficult to find. The NLMI computation for analysis and synthesis is shown to be as hard as Lyapunov stability analysis; a finite difference approximation scheme is proposed to solve the NLMIs.
Multivariate non‐linear time series modelling of exposure and risk in road safety research

Summary. A multivariate non‐linear time series model for road safety data is presented. The model is applied in a case‐study into the development of a yearly time series of numbers of fatal accidents (inside and outside urban areas) and numbers of kilometres driven by motor vehicles in the Netherlands between 1961 and 2000. The model accounts for missing entries in the disaggregated numbers of kilometres driven although the aggregated numbers are observed throughout. We consider a multivariate non‐linear time series model for the analysis of these data. The model consists of dynamic unobserved factors for exposure and risk that are related in a non‐linear way to the number of fatal accidents. The multivariate dimension of the model is due to its inclusion of multiple time series for inside and outside urban areas. Approximate maximum likelihood methods based on the extended Kalman filter are utilized for the estimation of unknown parameters. The latent factors are estimated by extended smoothing methods. It is concluded that the salient features of the observed time series are captured by the model in a satisfactory way.
An overview on controllability analysis of chemical processes

Controllability is one of the most important aspects of chemical process operability, because it can be used to assess the attainable operation of a given process and improve its dynamic performance. The purpose of this article is to outline the main methodologies that have been developed to deal with the assessment of process controllability and the improvement of its controllability characteristics. Several existing controllability assessment methods are reviewed and discussed. For improving the controllability characteristic of a process, there are two main design methods: the optimization-based method and the controllability indices-based anticipating sequential method. Advantages and disadvantages of these techniques are discussed. It has been emphasized that bifurcation analysis, as a powerful nonlinear analysis tool, could provide important guidance for making processes more controllable by eliminating or avoiding some undesirable behaviors of processes. Further challenges and developments in the field of process controllability are identified. © 2010 American Institute of Chemical Engineers AIChE J, 2010
Currents Induced in Human Bodies Sitting Inside a Vehicle Exposed to Lightning Electromagnetic Pulse Waves

The finite-different time-domain (FDTD) method is used to calculate currents and current densities induced in human bodies sitting inside a vehicle exposed to lightning electromagnetic pulse (LEMP) waves at frequencies from 10 Hz to 50 MHz. The induced current density in the driver's body increases as the frequency increases from 10 Hz to 50 MHz. Obtained maximum current densities of 0.01 to 0.8 A/cm2 at 50 MHz induced in human bodies for different numbers of persons are much higher than the threshold current density of 1 μA/cm2 for the steady-state current flow cases, which may cause unhealthy biological effects. However, the specific absorption (SA) rates for different numbers of persons sitting inside in the vehicle are considerably smaller than the value of 28.8 J/kg whole-body-averaged SA per pulse that has been proposed for the 1992 revision of ANSI C 95.1 Peak Power Exposure.
An extension of stochastic radio channel modeling considering propagation environments with clustered multipath components

A novel approach of a parametric stochastic radio channel model describes the dispersive nature of the wave propagation in indoor and outdoor environments with regard to delay and incidence angle. Effects of large-scale fluctuations are considered, too. Channel dispersion is mathematically denoted by the delay-angle spread function which results from the coherent superposition of the contributions arising from a certain number of multipath components (MPC). A classification of the propagation scenarios can be achieved by means of their topological properties. Local parameters defining the instantaneous constellation of the impinging MPC as well as global parameters giving a statistical characterization of the propagation environment (PE) are derived and form the elements of the channel model. This paper focuses on two indoor PE characterized by a line-of-sight (LOS) and a nonline-of-sight (NLOS) connection between the transmitter and receiver, respectively. Measurements in the 24 GHz range (ISM band) are presented to demonstrate the physical properties of the propagation process in both PE and to determine their global parameters. LOS scenarios show "discrete" MPC arising from specular reflections. In case of a NLOS situation the MPC exhibit a clustering pattern due to building and wall structures which can be statistically described by means of a cluster model, an extension of the previously given modeling approach.
Low noise NbN hot electron bolometer mixer at 4.3?THz

We have studied the sensitivity of a superconducting NbN hot electron bolometer mixer integrated with a spiral antenna at 4.3? THz. Using hot/cold blackbody loads and a beam splitter all in vacuum, we measured a double sideband receiver noise temperature of 1300? K at the optimum local oscillator (LO) power of 330? nW, which is about 12 times the quantum noise (h? /2kB). Our result indicates that there is no sign of degradation of the mixing process at the superterahertz frequencies. Moreover, a measurement method is introduced which allows us for an accurate determination of the sensitivity despite LO power fluctuations.
The transient response of linear antennas and loops

The transient response of straight wires and circular loops when short pulses are applied is studied experimentally and theoretically. It is shown that the initial response is always that of an infinitely long antenna at a frequency near the upper limit of the frequencies contained in the pulse provided this is sufficiently short so that the first reflection from the end of the wire or loop is not superimposed on it.
Quasi-Periodic Solutions in Nonlinear Asymmetric Oscillations

The existence of Aubry–Mather sets and infinitely many subharmonic solutions to the following p-Laplacian like nonlinear equation (p− 1)(φp(x)) + [αφp(x)− βφp(x)] + g(x) = h(t) is discussed, where φp(u) = |u|p−2u, p > 1, α, β are positive constants satisfying α − 1 p +β − 1 p = 2 n with n ∈ N, h is piece-wise two times differentiable and 2πp-periodic, g ∈ C1(R) is bounded, x± = max{±x, 0}, πp = 2π p sin(π/p) .
Adaptation, psychometric properties and factor structure of the Lithuanian interpersonal behaviours questionnaire (IBQ) in sport

Abstract Research on interpersonal behaviour is becoming increasingly important in a variety of social contexts and cultures. In educational practice, its importance is based on interactions as the educational context, in which learning, value formation and meaningful activities take place. The aim of this was to adapt the Interpersonal Behaviours Questionnaire (IBQ) in Sport into Lithuanian and to analyse its reliability and validity. 241 physically active men (mean age 27.01 ± 7.67) participated in this study. The adapted questionnaire showed good reliability (Cronbach α 0.927), content, criterion and structural validity (CFI 0.928, TLI 0.917, RMSEA 0.070, χ2/df 2.21) of Lithuanian version of IBQ in sport. The structural validity of the scale showed that supportive behaviours are strongly related to autonomy, competence and relatedness needs (rs ranged from .843 to .877), while supportive and thwarting behaviours have a moderate inverse relationship. However, supportive and thwarting behaviours are not diametrically opposed (r = −.597). Thus, the study shows that the IBQ in sport is valuable for analysing interpersonal relationships explaining the links between supportive and thwarting behaviour. The IBQ in sport can be a valuable tool for advancing research, enriching and improving educational practice in this field. Graphical abstract
All-optical RZ to NRZ format conversion using an ultrafast polarization bistable vertical-cavity surface-emitting laser

We experimentally demonstrate an all-optical RZ to NRZ format conversion at 1 Gbit/s using an ultrafast polarization bistable VCSEL. Our numerical simulation predicts that 40 Gbit/s signals can be converted. We also experimentally demonstrate an all-optical NRZ to RZ format conversion.