Miracle-dz/UniFAR-FTUs huggingface dataset:
Three-Dimensional CFD Rotordynamic Analysis of Gas Labyrinth Seals

Labyrinth seals are utilized inside turbomachinery to provide noncontacting control of internal leakage. These seals can also play an important role in determining the rotordynamic stability of the machine. Traditional labyrinth seal models are based on bulk-flow assumptions where the fluid is assumed to behave as a rigid body affected by shear stress at the interfaces. To model the labyrinth seal cavity, a single, driven vortex is assumed and relationships for the shear stress and divergence angle of the through flow jet are developed. These models, while efficient to compute, typically show poor prediction for seals with small clearances, high running speed, and high pressure. * In an effort to improve the prediction of these components, this work utilizes three-dimensional computational fluid dynamics (CFD) to model the labyrinth seal flow path by solving the Reynolds Averaged Navier Stokes equations. Unlike bulk-flow techniques, CFD makes no fundamental assumptions on geometry, shear stress at the walls, as well as internal flow structure. The method allows modeling of any arbitrarily shaped domain including stepped and interlocking labyrinths with straight or angled teeth. When only leakage prediction is required, an axisymmetric model is created. To calculate rotordynamic forces, a full 3D, eccentric model is solved. The results demonstrate improved leakage anti rotordynamic prediction over bulk-flow approaches compared to experimental measurements.
Axisymmetric toroidal equilibrium with flow and anisotropic pressure

Axisymmetric toroidal plasma equilibria with mass flows and anisotropic pressure are investigated. The equilibrium system is derived for a general functional form of the pressures, which includes both fluid models, such as the magnetohydrodynamic (MHD) and the double‐adiabatic models, and Grad’s guiding center model [Proceedings of the Symposium on Electromagnetics and Fluid Dynamics of Gaseous Plasmas, edited by J. Fox (Polytechnic Inst. of Brooklyn, New York, 1961), p. 37]. This allows for detailed comparisons between the models and clarifies how the ‘‘first hyperbolic region,’’ occurring in fluid theory when the poloidal flow is of the order of the poloidal sound speed, can be eliminated in guiding center theory. In the case of a pure toroidal rotation, macroscopic equations of state are derived from the guiding center model, characterized by a parallel temperature that is constant on each magnetic surface and a perpendicular temperature that varies with the magnetic field. The outward centrifugal shif.
Hypergéométrie et fonction zêta de Riemann

Introduction et plan de l'article Arriere plan Les resultats principaux Consequences diophantiennes du Theoreme $1$ Le principe des demonstrations des Theoremes $1$ a $6$ Deux identites entre une somme simple et une somme multiple Quelques explications Des identites hypergeometrico-harmoniques Corollaires au Theoreme $8$ Corollaires au Theoreme $9$ Lemmes arithmetiques Demonstration du Theoreme $1$, partie i) Demonstration du Theoreme $1$, partie ii) Demonstration du Theoreme $3$, partie i) et des Theoremes $4$ et $5$ Demonstration du Theoreme $3$, partie ii) et du Theoreme $6$ Encore un peu d'hypergeometrie Perspectives Bibliographie.
Radio structures of Seyfert galaxies. IV. Jets (. ) in NGC 1068 and NGC 4151

This paper presents and discusses new radio maps of the Seyfert galaxies NGC 1068 (at 1.4 and 15 GHz) and NGC 4151 (at 15 GHz) from the Very Large Array. The radio emission of NGC 1068 comprises a central component coincident with the optical nucleus and of size 0''. 7 x 0''. 3 in p.a. 28/sup 0/, a linear structure of extent 13'' in p.a. 33/sup 0/, and large scale emission of size at least 2'. The size and shape of the central component are very similar to those of the resolved optical nucleus, and the linear radio structure is probably related to optical ''flares'' and ''prominences'' which extend from the nucleus in the same direction. Linear polarization of magnitude 13% is detected at 15 GHz in the NE lobe of the linear structure. If Faraday rotation is small, the magnetic field is aligned along the radio source axis. Earlier radio maps of NGC 4151 show a highly elongated source of extent approx.3''. 5 in p.a. 77/sup 0/. In the center of this structure is found a double source of separation 0''. 45 in p.a. 83/sup 0/. The present observations resolve each component of this double and indicate that the more intense component hasmore » a flatter spectrum and is probably associated with the nucleus proper. « less
Universality in the stock exchange market

We consider the α re-scaled Standard & Poor's 100 (SP100) daily index positive returns and negative returns ( that we call, after normalization, the α positive fluctuations and α negative fluctuations, respectively. We use the Kolmogorov–Smirnov statistical test as a method to find the values of α that optimize the data collapse of the histogram of the α fluctuations with the truncated Bramwell–Holdsworth–Pinton (BHP) probability density function (pdf) and the truncated generalized log-normal pdf f LN that best approximates the truncated BHP pdf. The optimal parameters we found are , , and . Using the optimal α′s, we compute analytical approximations of the probability distributions of the normalized positive and negative SP100 index daily returns r(t). Since the BHP pdf appears in several other dissimilar phenomena, our result reveals a universal feature of the stock exchange markets.
Generalized classical dynamics, and the ‘classical analogue’ of a Fermioscillator

Various ways of generalizing classical canonical dynamics are considered. It is found that there exist systems of c-number Hamiltonian dynamics possessing neither canonically conjugate dynamical variables nor Lagrangian formulation. The possibility of a non c-number classical dynamics is then considered and realized. Elementary examples of both types of dynamics are examined, and emerge as classical analogues of a Fermioscillator. This is remarkable in view of the commonly held belief that a Fermi oscillator does not have a classical analogue. Not all possible classical analogues possess a Lagrangian formulation: those which do are of particular interest, since they provide the means of setting up a kind of Feynman principle.
R O -implications induced from C L -overlap functions on complete lattices

Recently, the concept of overlap functions on complete lattices has been introduced by extending the truth values set from the unit closed interval to complete lattices. On the other hand, the residual implications induced from commonly used aggregation functions (see, e.g., t-norms, pseudo-t-norms, uninorms, semi-uninorms and pseudo-uninorms), as a natural research topic of these commonly used aggregation functions in the case of lattice values, play a vital role in many-valued logic. In this paper, we consider the residual implications derived from the so-called C L -overlap functions on complete lattices which are the weak form of overlap functions on complete lattices. To be precise, ﬁrstly, we give the notion of R O implications which are residual implications induced from the C L -overlap functions on complete lattices and give some basic properties of them. Secondly, we focus on the conditions under which R O -implications can satisfy the certain algebraic properties possessed by implications on complete lattices. Finally, we give a one-to-one correspondence between different families of certain implications on complete lattices and the family of C L -overlap functions on complete lattices.
Dislocation Climb Forces

With a definition of standard state in accord with common usage in thermodynamics, the chemical potential of vacancies is shown to yield the Peach‐Koehler, Bardeen‐Herring formulas, without any modifications, for the total force on a dislocation. The theory includes a derivation of the effect of internal stresses on the chemical potential of vacancies. The stability of dislocations under various conditions of stress, external and internal, and various conditions of vacancy equilibration, is discussed.
Modelling energetic particles by a relativistic kappa-loss-cone distribution function in plasmas

Energetic particles found in planetary magnetospheres and other plasmas, where mirror geometries occur, often exhibit two typical characteristics: a pronounced high energy tail and an anisotropy. A relativistic kappa-loss-cone (KLC) distribution function fκL is initially developed which incorporates features of the well-known kappa type and loss-cone type, i.e. the anisotropy behaves as a loss-cone distribution; the energy satisfies ∝ [1/v2](κ+1) for a relatively large velocity v as a kappa distribution fκ does and spreads ∝ [1/p]κ+1 at the relativistic energies (where κ and p are the energy spectral index and the particle momentum, respectively). This indicates that the new distribution fκL obeys the power-law not only at the lower energies but also at the relativistic energies since the relativistic energy ∝ p. Numerical calculations are performed for a direct comparison between the new KLC distribution and the current kappa distribution, respectively. It is found that the regular kappa distribution generally decreases faster than the KLC distribution with the kinetic energy Ek especially when θ2 increases (where θ2 is the energy weight parameter), e.g. fκ/fκL ≲ 10−2 for Ek ≳ 2.0 MeV and θ2 ≳ 0.25. However, no big difference occurs between both distributions through energies up to ∼500 keV for θ2 ≲ 0.025. Furthermore, the regular kappa distribution containing either the temperature anisotropy or both the loss cone and temperature anisotropy is quite different from the KLC distribution. The new KLC distribution may be applicable to the outer radiation belts of the Earth, the inner Jovian magnetosphere and other plasmas (including the laboratory machine) where relativistic particles are present.
Keck high-resolution spectroscopy of Mrk 335: constraints on the number of emitting clouds in the broad-line region

We present high-resolution ( ~ 6 km S-1), high signal-to-noise ratio ( ~ 400 at Hot: line centre) spectroscopy of Mrk 335. Cross-correlation (CC) analysis of the data yields a lower limit of ~ 3 x 106 for the number of emitting clouds in the broad-line region (BLR) of this object. This limit is applicable for clouds with T=2 x 104 Kand an optical depth of ~ 104 in their Hot: line. The result is obtained from the absence of a CC signal in the data and from extensive Monte Carlo simulations that show the minimum number of clouds necessary in order to prevent the creation of a detectable CC signal. The simulations can be used to test any BLR model which is based on a contribution from discrete sources provided that the individual emission profile of the sources and their distribution are given. Current BLR models based on stellar atmospheres of bloated stars can be ruled out, unless the linewidth of an individual star exceeds 100 km S-1. The lower limit on the number of emitting clouds also provides constraints on traditional photoionization models for a system of clouds.
CCD PHOTOMETRY OF M 67 STARS USEFUL AS BVRI STANDARDS.

The use of CCD detectors for BVRI photometry is discussed. For the adopted filter system and detector linear transformations to the standard system with residuals, expressed as rms deviation per star, of only 1 or 2 percent, are determined. A region is defined in open cluster M67 where stars covering a (B-V) color-index range from -0.1 to +1.3 are calibrated at B, V, R, and I wavelengths. This region is useful for calibration of the system's sensitivity. Where overlap exists with previous observers, the magnitude zero points for M67 stars agree at better than the 1 percent level.
Effect of Ga implantation on the magnetic properties of permalloy thin films

Several regions of a 30 nm thick Ni80Fe20 (permalloy) thin film have been implanted using a focused ion-beam system with varying doses of Ga ions. Changes to their magnetization reversal have been investigated by Lorentz microscopy. Implantation with a dose of 1015 Ga+ cm−2 and 1016 Ga+ cm−2 has increased coercivity of the implanted region while no difference has been observed with a dose of 1014 Ga+ cm−2. Domain wall pinning was shown to be a major mechanism for the increase in coercivity. Also changes to the lattice parameter, composition, thickness and grain size in relation to magnetic properties were investigated using various transmission electron microscopy techniques. The lattice parameter change within the implanted region indicates that the stress can be a major contributor to the increase in coercivity. Relative contributions of changes in other factors such as Ni/Fe ratio, thickness, and grain size within the implanted area have also been discussed.
Testing for bi-directional rejection thresholds to sweetness and their links to sugar intake and sweet-taste drink consumption

Background and Aims: Sugar intake has been linked to obesity, however, the relationship between individual sugar perception and dietary choice remains unclear. The current study aims to measure individual bi-directional rejection thresholds and compare these measures to sugar intake and consumption patterns of sweet-taste beverages. Methods: A cross-section design will be used to analyse the relationship between sweetness perception, sucrose liking, and dietary intake. Participants will attend laboratory sessions to assess sucrose liking, ascending and descending rejection thresholds, and detection thresholds, and complete a 4-day weighed food-diary to assess dietary intake. ANCOVA will be used to test for differences in detection threshold and hedonic VAS ratings between the liking and disliking group, with age, gender, and BMI as covariates. A generalised linear mixed-models will be applied to test for differences in individual ascending versus descending rejection threshold across the two sweet liker status groups. Regression models will be used to test the role of ascending versus descending rejection thresholds on predicting sugar and sweet-taste beverage consumption. Discussion: More research focusing on links between individual sweetness perception and sugar intake will be important for elucidating the mechanism underpinning sensory effects on dietary behaviour.
A mixed-method approach to determining contact matrices in the Cox’s Bazar refugee settlement

Contact matrices are an important ingredient in age-structured epidemic models to inform the simulated spread of the disease between subgroups of the population. These matrices are generally derived using resource-intensive diary-based surveys and few exist in the Global South or tailored to vulnerable populations. In particular, no contact matrices exist for refugee settlements—locations under-served by epidemic models in general. In this paper, we present a novel, mixed-method approach for deriving contact matrices in populations, which combines a lightweight, rapidly deployable survey with an agent-based model of the population informed by census and behavioural data. We use this method to derive the first set of contact matrices for the Cox’s Bazar refugee settlement in Bangladesh. To validate our approach, we apply it to the UK population and compare our derived matrices with well-known contact matrices collected using traditional methods. Our findings demonstrate that our mixed-method approach successfully addresses some of the challenges faced by traditional and agent-based approaches to deriving contact matrices. It also shows potential for implementation in resource-constrained environments. This work therefore contributes to a broader aim of developing new methods and mechanisms of data collection for modelling disease spread in refugee and internally displaced person (IDP) settlements and better serving these vulnerable communities.
Is horizontal convection really “non‐turbulent?”

Within the geophysical community Horizontal Convection (HC) has been considered irrelevant or nearly so in driving large scale overturning flows, based primarily on an inference based on a century old experiment by Sandström (1908), and on a theoretical argument that would prevent HC to sustain a true turbulent flow, the latter deemed necessary to achieve mixing. We revisit Paparella and Young's (2002) argument with the aid of DNS of HC at Rayleigh number up to 1010. We argue that the criterion used by these authors is overly restrictive. On the contrary, geometrical statistics show that HC possesses the characteristic of turbulent flows. The surprising result is that HC can transport very large quantities of heat and sustain large amounts of diapycnal mixing with a surprisingly small amount of dissipation. Values of diapycnal mixing and dissipation in the ocean are shown to be consistent with a HC driven ocean provided the effect of wind‐forcing are included.
Negation and psychological dimensions

This paper analyses whether negation, as a modifier of degree, leads to different outcomes based on the psychophysical structure of the polar dimension along which the shift produced by the negator “not” occurs. In three experiments, the interpretation of negation in association with four different types of dimension was analysed. The types comprised: (1) strongly asymmetrical dimensions, topologically defined (in terms of the characteristics of Pole a/intermediates/Pole b) as unbounded range/no intermediates/point (e.g., open–closed); (2) moderately asymmetrical dimensions, topologically defined as unbounded range/range of intermediates/bounded range (e.g., wide–narrow); (3) slightly symmetrical dimensions, topologically defined as point/range of intermediates/point (e.g., full–empty); and (4) symmetrical dimensions, topologically defined as bounded range/point/bounded range (e.g., above–below). Results showed that the function of negation varies depending on which type of dimension is involved. These results are discussed in relation to previous literature, where the definition of various types of antonyms was based on the applicability of different lexical modifiers of degree.
Pressure-temperature-La concentration three-dimensional phase diagram of La-modified PbTiO3 determined by Raman scattering

A detailed Raman scattering study was performed on lanthanum-modified lead titanate (PLT) with compositions varying from pure PbTiO3 to La 20.0 at. %, for temperatures ranging from 8 K to temperatures above the Curie temperature and hydrostatic pressures up to 7.5 GPa. A complete La concentration-pressure-temperature three dimensional phase diagram was determined, by using the E(TO1) soft mode frequency as the main probe.
Diffusion and dispersion in magnetohydrodynamic turbulence: The influence of mean magnetic fields

The properties of magnetohydrodynamic (MHD) turbulence under the influence of a strong mean magnetic field are investigated from the Lagrangian viewpoint by tracking fluid particles in direct numerical simulations. The particle trajectories show characteristic bends near vortex sheets. A strong mean magnetic field leads to preferential diffusion parallel to the mean magnetic field. The two-particle relative dispersion process shows a dependence on the orientation of the initial separation vector. The relative dispersion is slowed down for initial separation vectors aligned with the mean magnetic field. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Mathematical modelling of ground temperature with suction velocity and radiation

This paper investigates the problem of ground temperature under a vegetative cover with time dependent suction and radiative heat transfer. By assuming that the ground radiates heat from its’ surface and that the radiative heat flux takes a differential form which follows that of Tarkhar et al [1], the problem was formulated. By imposing a regular time dependent perturbation, the problem was solved. The numerical results and graphs were computed using the software, Mathematica. Results revealed that individual and simultaneous increase in flow parameters caused decrease in the temperature.
Weak type $(1,1)$ estimates for Marcinkiewicz integrals with rough kernels

We consider Marcinkiewicz integrals arising from rough kernels satisfying the $L\log L$ condition on the unit $(n-1)$-sphere and prove the weak type (1, 1) estimates. We also prove the weighted weak type (1, 1) estimates with certain $A_1$-weights. In this case the $L\log L$-condition is replaced by the $L^q$-condition with $q>1$.
Complex dynamics of Möbius semigroups

Abstract We study the dynamics of semigroups of Möbius transformations on the Riemann sphere, especially their Julia sets and attractors. This theory relates to the dynamics of rational functions, rational semigroups, and Möbius groups and we compare and contrast these theories. We particularly examine Caruso’s family of Möbius semigroups, based on a random dynamics variant of the Fibonacci sequence.
Cosmic evolution of black holes and galaxies to z=0.4

Abstract We test the evolution of the correlation between black hole mass and bulge properties, using a carefully selected sample of 20 Seyfert 1 galaxies at z=0.36 ±0.01. We estimate black hole mass from the Hβ line width and the optical luminosity at 5100 Å, based on the empirically calibrated photo-ionization method. Velocity dispersion are measured from stellar absorption lines around Mgb (5175 Å) and Fe (5270 Å) using high S/N Keck spectra, and bulge properties (luminosity and effective radius) are measured from HST images by fitting surface brightness. We find a significant offset from the local relations, in the sense that bulge sizes were smaller for given black hole masses at z=0.36 than locally. The measured offset is Δ M•=0.62 ± 0.10, 0.45 ±0.13, 0.59 ±0.19, respectively for M•–σ, M•–Lbulge, and M•–Mbulge relations. At face value, this result implies a substantial growth of bulges in the last 4 Gyr, assuming that the local M•–bulge property relation is the universal evolutionary end-point. This result is consistent with the growth of black holes predating the final growth of bulges at these mass scales (〈σ〉=170 km s−1).
NATURAL FREQUENCY CHANGES OF A CRACKED TIMOSHENKO BEAM BY MODIFIED FOURIER SERIES

A new method is presented in this paper for computing the natural frequencies of a Timoshenko beam with an arbitrary number of transverse open cracks. The essence of this new method lies in the use of a kind of modified Fourier series (MFS) which is developed particularly for a Timoshenko beam having an arbitrary number of transverse open cracks. Unlike the conventional Fourier series, the modified Fourier series can approach a function with internal geometrical discontinuities. Based on the modified Fourier series, one can treat the cracked Timoshenko beam in the usual way and thus reduces the problem to a simple one. By using the present method, only standard linear eigenvalue equations, rather than non-linear algebraic equations, need to be solved. All the formulae are expressed in matrix form that renders the task of computer coding quite straightforward.
CHAOTIC MASKING WITHOUT SYNCHRONIZATION

A method of secure communication based on the inversion of a chaotic dynamical system is analyzed. The approach does not require chaotic synchronization of two or several oscillators to be used. The influence of noise in the communication channel and parameter mismatch on the quality of decoded signal is discussed. The feasibility of the approach is demonstrated by the examples of nonautonomous pendulum equation and autonomous Rossler oscillator.