Miracle-dz/UniFAR-FTUs huggingface dataset:
A Reynolds stress model for near-wall turbulence

A tensorially consistent near-wall second-order closure model is formulated. Redistributive terms in the Reynolds stress equations are modelled by an elliptic relaxation equation in order to represent strongly non-homogeneous effects produced by the presence of walls; this replaces the quasi-homogeneous algebraic models that are usually employed, and avoids the need for ad hoc damping functions. A quasi-homogeneous model appears as the source term in the elliptic relaxation equation-here we use the simple Rotta return to isotropy and isotropization of production formulae. The formulation of the model equations enables appropriate boundary conditions to be satisfied. The model is solved for channel flow and boundary layers with zero and adverse pressure gradients. Good predictions of Reynolds stress components, mean flow, skin friction and displacement thickness are obtained in various comparisons to experimental and direct numerical simulation data. The model is also applied to a boundary layer flowing along a wall with a 90°, constant-radius, convex bend. Because the model is of a general, tensorially invariant form, special modifications for curvature effects are not needed; the equations are simply transformed to curvilinear coordinates. The model predicts many important features of this flow. These include: the abrupt drop of skin friction and Stanton number at the start of the curve, and their more gradual recovery after the bend; the suppression of turbulent intensity in the outer part of the boundary layer; a region of negative (counter-gradient) Reynolds shear stress; and recovery from curvature in the form of a Reynolds stress ‘bore’ propagating out from the surface. A shortcoming of the present model is that it overpredicts the rate of this recovery. A heat flux model is developed. It is shown that curvature effects on heat transfer can also be accounted for automatically by a tensorially invariant formulation.
Nonuniform fast cosine transform and the Chebyshev PSTD algorithm

Fast cosine transform (FCT) has many applications in signal processing and computational electromagnetics. Many efforts have been made in developing the efficient FCT algorithm. However, to use the regular FCT algorithm, the input data have to be uniformly distributed. This is a major limitation of the Chebyshev pseudospectral time domain (PSTD) method. We developed two different fast algorithms for forward nonuniform discrete cosine transform (NUFCT) by using the regular Fourier matrices. These algorithms have the complexity of O(Nlog/sub 2/N) where N is the number of data points. Unlike the uniform fast cosine transform which is identical to its inverse, the inverse nonuniform FCT cannot share the same algorithm. We use the conjugate-gradient fast Fourier transform (CG-FFT) methods for the fast inverse cosine transform (NU-IFCT).
Radius of convexity of partial sums of a certain power series

Let , be regular in the unit disc . G. Szegö [5] and Y. Miki [3] proved that if f(z), given by (1), is univalent (starlike with respect to the origin; convex; close-to-convex in E) then any one of the partial sums , is also univalent (starlike with respect to the origin; convex; close-to-convex) in |z| < ¼and that the constant ¼ cannot be replaced by a larger one.
A MAGNETIC RECONNECTION MECHANISM FOR THE GENERATION OF ANOMALOUS COSMIC RAYS

The recent observations of the anomalous cosmic ray (ACR) energy spectrum as Voyager 1 and Voyager 2 crossed the heliospheric termination shock have called into question the conventional shock source of these energetic particles. We suggest that the sectored heliospheric magnetic field, which results from the flapping of the heliospheric current sheet, piles up as it approaches the heliopause, narrowing the current sheets that separate the sectors and triggering the onset of collisionless magnetic reconnection. Particle-in-cell simulations reveal that most of the magnetic energy is released and most of this energy goes into energetic ions with significant but smaller amounts of energy going into electrons. The energy gain of the most energetic ions results from their reflection from the ends of contracting magnetic islands, a first-order Fermi process. The energy gain of the ions in contracting islands increases their parallel (to the magnetic field B) pressure p∥ until the marginal fire-hose condition is reached, causing magnetic reconnection and associated particle acceleration to shut down. Thus, the feedback of the self-consistent development of the energetic ion pressure on reconnection is a crucial element of any reconnection-based, particle-acceleration model. The model calls into question the strong scattering assumption used to derive the Parker transport equation and therefore the absence of first-order Fermi acceleration in incompressible flows. A simple one-dimensional model for particle energy gain and loss is presented in which the feedback of the energetic particles on the reconnection drive is included. The ACR differential energy spectrum takes the form of a power law with a spectral index slightly above 1.5. The model has the potential to explain several key Voyager observations, including the similarities in the spectra of different ion species.
Two-Phase Nonturbulent Flow with Applications

We model dynamics of two almost immiscible fluids of different densities using the Stokes equations with the Dirac distribution representing the sink or source point. The equations are solved by regularizing the Dirac distribution and then using an iterative procedure based on the finite element method. Results have potential applications in water pollution problems and we present two relevant situations. In the first one, we simulate extraction of a light liquid trapped at the bottom of a pond/lake and, after being disturbed, it rises toward the surface. In the second case, we simulate heavy liquid leaking from a source and slowly dropping on an uneven bottom.
Quelques martingales associées à l'intégrale du processus d'ornstein- uhlenbeck. application à l'étude despremiers instants d'atteinte

Let be the Ornstein-Uhlenbeck process with parameter β starting at y and In this paper, several martingales are built, related to the two-dimensional process ; then, we give explicitly the Laplace transforms of the random vectors and where and Next these results are extended to the case of an Ornslein-Uhlenbeck process driven by the “hyperbolic” drift
Detection of 130 “Diffuse” Galactic H II Regions

The paper reports the results of a search for diffuse Galactic H II regions using radio recombination lines. Unlike most previous surveys, which have been directed toward fairly bright, compact radio continuum sources, we observed unprepossessing objects that might be optically obscured analogs to the Rosette Nebula. The sources observed here are typically a factor of 2 fainter in the continuum than those that have been detected before. One hundred thirty nebulae have been measured in radio recombination lines for the first time; most require at least one main-sequence O star to provide their ionization. The diffuse H II regions appear to have essentially the same distribution in the Galaxy as compact H II regions. There is some indication that the diffuse nebulae have a low abundance of ionized helium, possibly due to their low excitation. Several newly discovered nebulae are associated with peculiar kinematic features in the Galactic nucleus. The surface density of radio H II regions in the inner Galaxy follows the surface density of CO fairly closely from 4 ≤ R ≤ 8 kpc. In this area, there is ∼1 radio H II region for each 106 M☉ of molecular hydrogen. However, H II regions are a factor ∼2 more confined to the Galactic plane than the molecular gas from which they form.
Steady flow in the laminar boundary layer of a gas

If the boundary-layer equations for a gas are transformed by Mises’s transformation, as was done by Kármán & Tsien for the flow along a flat plate of a gas with unit Prandtl number σ, the computation of solutions is simplified, and use may be made of previously computed solutions for an incompressible fluid. For any value of the Prandtl number, and any variation of the viscosity μ with the temperature T, after the method has been applied to flow along a flat plate (a problem otherwise treated by Crocco), the flow near the forward stagnation point of a cylinder is calculated with dissipation neglected, both with the effect of gravity on the flow neglected and with this effect retained for vertical flow past a horizontal cylinder. The approximations involved by the neglect of gravity are considered generally, and the cross-drift is calculated when a horizontal stream flows past a vertical surface. When σ =1, μ∞T, and the boundary is heat-insulated, it is shown that the boundary-layer equations for a gas may be made identical, whatever be the main stream, with the boundary-layer equations for an incompressible fluid with a certain, determinable, main stream. The method is also applied to free convection at a flat plate (with the heat of dissipation and the variation with altitude of the state of the surrounding fluid neglected) and to laminar flow in plane wakes, but for plane jets the conditions σ =1, μ∞T, previously imposed by Howarth,are also imposed here in order to obtain simple solutions.
An optimized small‐cell planning procedure for Heterogeneous Network to improve network energy efficiency

Cell planning in conventional networks has gained more attention as it directly affects the network performance and deployment cost. Existing cell planning methodologies are framed either with identical base stations or constructing a network without any infrastructure. But heterogeneous networks (HetNets) allow the service provider to deploy small cells over the region to enhance the network performance and signal coverage probability. Thus, a small‐cell planning procedure is presented in this research work considering the low‐powered base station and deployment cost to enhance the energy efficiency of the HetNet. An adaptive fuzzy expert system is used for cell dimensioning, and a nature‐inspired ant colony optimization model is employed for automatic base station placement. Simulation analysis demonstrates that the proposed small‐cell planning procedure attains better energy efficiency and user satisfaction ratio compared to conventional planning strategies. In the two cases of simulation analysis, the proposed model attains an average of 85% user satisfaction ratio for case 1 and 87% for case 2, which is better than existing strategies like density‐based spatial clustering of applications with noise (DBSCAN), k‐means, and number‐based spatial clustering (NBSC) algorithms.
Multiscale Markov random fields and constrained relaxation in low level image analysis

The authors investigate a new approach to multigrid image analysis based on Markov random field (MRF) models. The multigrid algorithms under consideration are based on constrained optimization schemes. The global optimization problem associated with MRF modeling is solved sequentially over particular subsets of the original configuration space. Those subsets consist of constrained configurations describing the desired resulting field at different scales. The constrained optimization can be implemented via a coarse-to-fine multigrid algorithm defined on a sequence of consistent multiscale MRF models. The proposed multiscale paradigm yields fast convergence toward high-quality estimates when compared to standard monoresolution or multigrid relaxation schemes. <<ETX>>
Ultrawideband Compact Lightweight Biconical Antenna With Capability of Various Polarizations Reception for Modern UAV Applications

This article presents the results of numerical modeling, optimization, fabrication and performance measurements of a new biconical antenna for modern unmanned aerial vehicle (UAV) applications. The developed antenna effectively combines a set of fundamental constructive and electromagnetic requirements, which include compact structure and small total dimensions, lightweight, and ultrawideband operating frequency range with the capability of receiving or transmitting both circular, horizontal, vertical, and one of slant linear polarizations. For the first time, an effect of multiple resonance reflections in the structure of biconical antenna with a polarizer and deterioration of antenna’s matching and gain characteristics at a series of frequencies was detected by measurements. Theoretical analysis of the observed resonances has been carried out in this article. Possible ways to exclude resonances are given. In the most part of operating frequency range 2–18 GHz, the developed antenna provides voltage standing wave ratio (VSWR) less than 2 and gain higher than 3 dBi for the -45° slant polarization, while the +45° slant polarization is discriminated by more than 15 dB.
Improve Self-Adaptive Control Parameters in Differential Evolution for Solving Constrained Engineering Optimization Problems

We proposed a new improvement of self-adaptive strategy for controlling parameters in di ﬀ erential evolution algorithm (ISADE). The di ﬀ erential evolution (DE) algorithm has been used in many practical cases and has demonstrated good convergence properties. It has only a few control parameters as number of particles ( NP ), scaling factor ( F ) and crossover control ( CR ), which are kept ﬁxed throughout the entire evolutionary process. However, these control parameters are very sensitive to the setting of the con-trol parameters based on their experiments. The value of control parameters depend on the characteristics of each objective function, so we have to tune their value in each problem that mean it will take too long time to perform. We present a new version of the DE algorithm for obtaining self-adaptive control parameter settings that show good performance on numerical benchmark problems and constrained engineering optimization problems.
Echocardiographic and hemodynamic changes in patients with high-grade varicocele

Varicocele is abnormal tortuosity and dilatation of the pampiniform plexus veins within the spermatic cord. Varicocele is associated with testicular atrophy, hypogonadism, impaired semen analysis values, or decreased testosterone production. Varicocele is a progressive disease and should be treated because it may be a systemic disease that can be associated with cardiovascular abnormalities. We hypothesize in this study that cardiovascular and hemodynamic pathologies may occur in varicocele patients. In this prospective, multicentric, multidisciplinary study, patients diagnosed with high-grade left varicocele in the urology clinic underwent semen analysis, total testosterone determination, and scrotal Doppler ultrasonography. In addition, blood pressure measurement and echocardiographic evaluation were performed by blinded cardiologists in both the varicocele patients and the healthy control group. The study was carried out with 103 varicocele patients and 133 healthy individuals who formed the control group. Diastolic blood pressure (P ═ 0.016), left ventricular end diastolic (P < 0.001) and systolic diameter (P < 0.001), ejection fraction (P < 0.001), pulmonary arterial pressure (P < 0.001), and aortic distensibility (P < 0.001) values were significantly higher in varicocele patients compared with controls; interventricular septum wall thickness (P ═ 0.022), aortic systolic (P < 0.001) and diastolic diameter (P < 0.001), aortic systolic (P < 0.001) and diastolic diameter index (P < 0.001), and aortic stiffness index (P < 0.001) values were significantly lower in varicocele patients. The mean aortic distensibility of non-normozoospermic group was lower than that of normozoospermic group (P ═ 0.041). There was no statistically significant relationship between thickest vein diameter in spermatic cord and cardiological parameters. This study showed that symptomatic patients with high-grade varicocele had a higher risk of cardiovascular and hemodynamic disease. We recommend that men with high-grade symptomatic varicocele with impaired semen analysis undergo cardiovascular and hemodynamic evaluation regardless of their spermatic vein diameter.
Optimisation in Non-Life Insurance

In this course we review two optimisation problems. The first problem is to minimise the ruin probability by proportional reinsurance. The results are complemented by some asymptotic considerations of the minimal ruin probability and the optimal strategy. The second problem is to maximise the expected discounted dividend payout. Both problems are solved via the Hamilton–Jacobi–Bellman approach.
Compensation profiles among private sector employees in Sweden: Differences in work-related and health-related outcomes

How experiences and perceptions of pay and pay setting relate to employees’ job performance, willingness to remain in the organization, and health has been the subject of much debate. Previous research has typically used a variable-centered approach to investigate associations between different pay-related factors and such outcomes. In contrast, we used latent profile analysis to explore combinations of compensation characteristics (pay level, perceived horizontal pay dispersion, and procedural quality, i.e., transactional leadership and procedural pay-setting justice), combining relevant theories on the subject. Based on a nationally representative sample of private sector employees in Sweden (N = 1,146), our study identified six compensation profiles. Our key findings show, first, that higher levels of pay were generally associated with better performance, lower turnover intention, better self-rated health, and lower work-related exhaustion, especially when combined with perceptions of high procedural quality. Second, in terms of perceived horizontal pay dispersion, the results indicate that pay compression may be associated with beneficial outcomes, particularly when combined with high procedural quality. Third, procedural quality was generally associated with favorable work-related and health-related outcomes, although such positive effects may be contingent upon pay level and perceived horizontal pay dispersion. In conclusion, while pay level, perceptions of horizontal pay dispersion, and procedural quality may all matter for employee outcomes, it is important to consider their combinations.
Study of optical clearing of blood by immersion method

Light scattering in blood caused by refractive index mismatch between erythrocyte cytoplasm and blood plasma leads to a reduction in imaging spatial resolution, imaging depth and contrast of optical imaging techniques. A possible solution to this problem is of the addition of biocompatible clearing agents, such as glucose, fructose, glycerol, dextrans etc. The basic principle of the optical clearing technique is refractive index matching between erythrocyte cytoplasm and blood plasma. Optical clearing, a technique that has been successfully demonstrated with biologic tissue, represents a promising approach to increasing the imaging depth for various techniques, for example optical coherence tomography (OCT). OCT is based on low-coherence interferometry to produce cross-sectional tomographic imaging of the internal microstructure in materials and biological tissues by measuring the echo time delay and magnitude of backscattered light. One of the main advantages of this technique is the ability to investigate turbid and highly scattering media, such as whole blood. To determine the optimal concentration of clearing agents required for blood optical clearing in order to improve light penetration depth for optical coherence tomography, clearing agents such as glucose and fructose, with various concentrations were added to blood and investigated by OCT. Changes in light attenuation and sedimentation and aggregation properties of blood depending on particular agent and its concentration were studied.
Vortex structure and dynamics in the near field of a coaxial jet

We present results from an experimental and numerical investigation into the structure of vortex patterns and the dynamics of their interactions for the incompressible flow in the near field of a round coaxial jet issuing into a quiescent ambient fluid. A two-colour planar laser-induced-fluorescence technique is used to document the flow field via still photographs and ciné sequences over a limited range of parameters. We examine the effects of varying the velocity ratio as well as the absolute velocities of the two coaxial streams for equal densities and for a single area ratio. Results show that a variety of widely differing near-field vortex patterns can arise, with very different interaction dynamics, which can depend both on the velocity ratio and on the absolute velocities of the two streams. The observed vortex structures and their dynamics are interpreted in terms of the instability of the initially cylindrical and concentric vorticity layers separating each of the fluid streams, and their subsequent rollup to form wake-like or shear-layer-like vortices. Our results show that in addition to the velocity jump across each of these vorticity layers, an accounting of the layer thicknesses and the wake defect within each layer can be essential to understanding the resulting near-field structure that occurs. Ensuing dynamical interactions between the vortices formed from each layer can produce a strong coupling between the development of the two layers. These resulting vortex structures and interaction dynamics are also seen to produce widely differing mixing patterns in the jet near field.
On the importance of interpretable machine learning predictions to inform clinical decision making in oncology

Machine learning-based tools are capable of guiding individualized clinical management and decision-making by providing predictions of a patient’s future health state. Through their ability to model complex nonlinear relationships, ML algorithms can often outperform traditional statistical prediction approaches, but the use of nonlinear functions can mean that ML techniques may also be less interpretable than traditional statistical methodologies. While there are benefits of intrinsic interpretability, many model-agnostic approaches now exist and can provide insight into the way in which ML systems make decisions. In this paper, we describe how different algorithms can be interpreted and introduce some techniques for interpreting complex nonlinear algorithms.
A deep CCD search for low surface brightness galaxies in A3574

A significant area (about 0.5 sq deg) of the cluster A3574 was surveyed using the large-format Thomson CCD, operating at f/1 on the AAT. The candidate cluster low-surface brightness galaxies (LSBG) were selected in terms of their position in isophotal magnitude-isophotal area plot, and 300 candidates with exponential sale-sizes greater than 2 arcsec. The largest objects have scale-sizes of 12-14 arcsec, which correspond to about 3 h/kpc if they are genuine cluster members. The lowest surface brightness objects found have central values around 26.5 Vmu. It is concluded that A 3574 has a particularly large LSBG content both in terms of the surface density and the LSBG-to-giant-galaxy ratio. A catolog of the 300 candidate objects is presented and compared with the LSBG population of this cluster.
Elastic strain of freely suspended single-wall carbon nanotube ropes

We have induced large elastic strains in ropes of single-wall carbon nanotubes, using an atomic force microscope in lateral force mode. Freely suspended ropes were observed to deform as elastic strings with tension proportional to elongation. Ropes were elastically deformed over >10 cycles without showing signs of plastic deformation. The maximum strain observed, 5.8±0.9%, gives a lower bound of 45±7 GPa for the tensile strength (specifically, yield stress) of single-wall nanotube ropes.