Miracle-dz/UniFAR-FTUs huggingface dataset:
Unsteady Flow of a Dusty Incompressible Fluid between Two Parallel Plates under an Impulsive Pressure Gradient

In the present investigation, an attempt is made to study the unsteady flow or an incompressible viscous fluid with uniform distribution of dust particles between two parallel plates under an impulsive pressure gradient. Analytical expressions for velocities of the fluid and the dust particles have been obtained. The variation of total fluxes for fluid and dust particles has been discussed. The influence on skin friction has been noticed.
On the geometry of sets satisfying the sequence selection property

In this paper we study fundamental directional properties of sets under the assumption of condition (SSP ) (introduced in [2]). We show several transversality theorems in the singular case and an (SSP )-structure preserving theorem. As an illustration, our transversality results are used to prove several facts concerning complex analytic varieties. The (SSP )-property is most suitable for understanding transversality in the Lipschitz category. This property is shared by a large class of sets, in particular by subanalytic sets or by definable sets in an o-minimal structure.
GEOMETRIC RELATIONS BETWEEN SCALES OF SMALL COLOUR DIFFERENCES

Varying magnitude of colour differences from threshold up to moderate size in painted sample pairs at five CIE colour centers was estimated by grey scale assessment. Painted samples were produced for constant step width along the main axes of previously determined threshold (x,y,Y)-ellipsoids with lightness variation at constant (x,y)-chromaticity starting with threshold length and enlarging it five times for moderate magnitude of colour difference. Pairs were formed for linear extensions along axes and for diagonal combinations at equal step width between axes. The model under test assumes additive linear scale extension in constant proportions of the threshold (x,y,Y)-ellipsoid for increasing magnitude of perceived colour difference and correlates perceptual main colour characters with main ellipsoid axes. Both assumptions were falsified to some degree: in general, magnitude of colour difference varies differently, though close to linear, and slightly subadditive for the three axes and for the different colour centers; the short (x,y)-ellipse axis in some cases is not correlated with a perceptual hue vector component, and the main lightness direction sometimes is tilted in relation to the (x,y)-plane. Three colour-difference formulae do not provide better global predictions than the local (x,y,Y)-ellipsoid formulae. The results may be used for more detailed modeling of colour-difference formulae and for tolerance settings at different ranges of colour difference. © 1999 John Wiley & Sons, Inc. Col Res Appl, 24, 78–92, 1999
Sensitivity of a general circulation model to parameterizations of cloud–turbulence interactions in the atmospheric boundary layer

Several approaches to parameterize the turbulent transport of momentum, heat, water vapour and cloud water for use in a general circulation model (GCM) have been tested in 1-dimensional and 3-dimensional model simulations. The schemes differ with respect to their closure assumptions (conventional eddy diffusivity model versus turbulent kinetic energy closure) and also regarding their treatment of cloud–turbulence interactions. The basic properties of these parameterizations are discussed first in relation to column simulations of a stratocumulus–topped atmospheric boundary layer (ABL) under a strong subsidence inversion during the KONTROL experiment in the North Sea. It is found that the K-models tend to decouple the cloud layer from adjacent layers above and below because the turbulent activity is calculated from local variables. The higher-order scheme performs better in this respect because internally generated turbulence can be transported up and down through the action of turbulent diffusion. Thus, the TKE-scheme provides not only a better link between the cloud and the sub-cloud layer but also between the cloud and the inversion as a result of cloud-top entrainment. In the stratocumulus case study, where the cloud is confined by a pronounced subsidence inversion, increased entrainment favours cloud dilution through enhanced evaporation of cloud droplets. In the GCM study, however, additional cloud-top entrainment supports cloud formation because indirect cloud generating processes are promoted through efficient ventilation of the ABL, such as the enhanced moisture supply by surface evaporation and the increased depth of the ABL. As a result, tropical convection is more vigorous, the hydrological cycle is intensified, the whole troposphere becomes warmer and moister in general and the cloudiness in the upper part of the ABL is increased. DOI: 10.1034/j.1600-0870.1995. t01-1-00004.x
Advection of a passive scalar by a vortex couple in the small-diffusion limit

We study the advection of a passive scalar by a vortex couple in the small-diffusion (i.e. large Péclet number, Pe) limit. The presence of weak diffusion enhances mixing within the couple and allows the gradual escape of the scalar from the couple into the surrounding flow. An averaging technique is applied to obtain an averaged diffusion equation for the concentration inside the dipole which agrees with earlier results of Rhines & Young for large times. At the outer edge of the dipole, a diffusive boundary layer of width O(Pe−½) forms; asymptotic matching to the interior of the dipole yields effective boundary conditions for the averaged diffusion equation. The analysis predicts that first the scalar is homogenized along the streamlines on a timescale O(Pe−$\frac{1}{3}$). The scalar then diffuses across the streamlines on the diffusive timescale, O(Pe). Scalar that diffuses into the boundary layer is swept to the rear stagnation point, and a finite proportion is expelled into the exterior flow. Expulsion occurs on the diffusive timescale at a rate governed by the lowest eigenvalue of the averaged diffusion equation for large times. A split-step particle method is developed and used to verify the asymptotic results. Finally, some speculations are made on the viscous decay of the dipole in which the vorticity plays a role analogous to the passive scalar.
Local Piezoelectric Hysteresis Loops for the Study of Electrical Properties of 0.7Pb(Mg1/3Nb2/ 3)O3-0.3PbTiO3 Thin Films: Bottom Electrode Dependence and Film Thickness Effect

0.7Pb(Mg 1/3 Nb 2/3 )O 3 –0.3PbTiO 3 (PMN–PT 70/30) thin films, 400 and 600 nm thick, have been grown on Pt and LaNiO 3 (LNO) bottom electrodes by rf magnetron sputtering. For each thickness, local piezoelectric hysteresis loops evidence that the individual PMN-PT grains deposited on LNO always require much higher voltage than the ones grown on Pt for switching. The average piezoelectric activity of grains is shown to be the highest for LNO electrode. For each electrode, film thickness has no significantly effect on the average coercive voltage and piezoelectric activity measured on the loops. A simple charge model explains this result.
Random Vibration of Degrading, Pinching Systems

A differential equation model to describe pinching, degrading response of hysteretic elements is presented. The model consists of a nonpinching hysteretic element, in series with a “slip-lock” element. Zero mean response statistics for a single degree of freedom oscillator whose stiffness is described by the series model, computed by equivalent linearization and by Monte Carlo simulation, are compared. The model response statistics are seen to be reasonable estimated by equivalent linearization.
Natural Topology

We give a theoretical and applicable framework for dealing with real-world phenomena. Joining pointwise and pointfree notions in BISH, natural topology gives a faithful idea of important concepts and results in intuitionism. Natural topology is well-suited for practical and computational purposes. We give several examples relevant for applied mathematics, such as the decision-support system Hawk-Eye (used in professional tennis), and various real-number representations. We compare CLASS, INT, RUSS, BISH and formal topology. There are links with physics, regarding the topological character of our physical universe. Translation of intuitionistic results to BISH is facilitated by our framework, using transfinite countable-ordinal induction in Brouwer's style. We study quotients of Baire space, and obtain constructive metrizability of star-finitary spaces. Silva spaces arise as example of non-metrizable natural spaces. Finally we discuss the role of Church's Thesis in physics.
Estimating Technical Efficiency of Waterleaf Production in a Tropical Region

Abstract Information on economics of production of minor vegetables is largely limited. This is the case for waterleaf [Talinum triangulare (Jacq). Wild]. Farm-level, output-oriented technical efficiency indices were estimated by fitting stochastic production frontier functions to survey data collected from waterleaf producers. By use of the Maximum Likelihood analysis, asymptotic parameter estimates were evaluated to describe efficiency determinants. The most critical production factors were labor, irrigation, and use of organic manure. The mean efficiency term, 0.65, indicates that waterleaf output could be increased with available technology. Some socioeconomic factors were evaluated to determine their influences on the ability of producers to be efficient in input use. Waterleaf production may be able to contribute to income derived from vegetable production in tropical environments.
ON THE SPIRAL STRUCTURE OF M33

The H II region distribution of M33, published by Boulesteix et al., is analysed using a 2-D Fourier transform technique. We show that the 2-armed structure extends to r~28'. Beyond that radius, the distribution shows a very chaotic behavior that agrees with Elmegreen adn Elmegreen arm classification. By using the inverse Fourier transform (funcations that represent the radial density of the m-armed components), and assuming that places of resonances have a low surface density of H II regions, we can infer a possible place for the corotation radius and so the pattern speed.
Testing for structural breaks in the presence of data perturbations: impacts and wavelet-based improvements

This paper investigates how classical measurement error and additive outliers (AO) influence tests for structural change based on F-statistics. We derive theoretically the impact of general additive disturbances in the regressors on the asymptotic distribution of these tests for structural change. The small sample properties in the case of classical measurement error and AO are investigated via Monte Carlo simulations, revealing that sizes are biased upwards and that powers are reduced. Two-wavelet-based denoising methods are used to reduce these distortions. We show that these two methods can significantly improve the performance of structural break tests.
Non-metric gravity: II. Spherically symmetric solution, missing mass and redshifts of quasars

We continue the study of the non-metric theory of gravity introduced by Krasnov (2006 Preprint hep-th/0611182) and obtain its general spherically symmetric vacuum solution. It respects the analog of the Birkhoff theorem, i.e. the vacuum spherically symmetric solution is necessarily static. As in general relativity, the spherically symmetric solution is seen to describe a black hole. The exterior geometry is essentially the same as in the Schwarzschild case, with power-law corrections to the Newtonian potential. The behaviour inside the black-hole region is different from the Schwarzschild case in that the usual spacetime singularity gets replaced by a singular surface of a new type, where all basic fields of the theory remain finite but metric ceases to exist. The theory does not admit arbitrarily small black holes: for small objects, the curvature on the would-be horizon is so strong that non-metric modifications prevent the horizon from being formed. The theory allows for modifications of gravity of a very interesting nature. We discuss three physical effects, namely (i) correction to Newton's law in the neighborhood of the source, (ii) renormalization of effective gravitational and cosmological constants at large distances from the source and (iii) additional redshift factor between spatial regions of different curvature. The first two effects can be responsible, respectively, for the observed anomaly in the acceleration of the Pioneer spacecraft and for the alleged missing mass in spiral galaxies and other astrophysical objects. The third effect can be used to propose a non-cosmological explanation of high redshifts of quasars and gamma-ray bursts.
Normal forms approach to diffusion near hyperbolic equilibria

We consider the exit problem for small white noise perturbation of a smooth dynamical system on the plane in the neighbourhood of a hyperbolic critical point. We show that if the distribution of the initial condition has a scaling limit then the exit distribution and exit time also have a joint scaling limit as the noise intensity goes to zero. The limiting law is computed explicitly. The result completes the theory of noisy heteroclinic networks in two dimensions. The analysis is based on normal forms theory.
Birational stability of the cotangent bundle

We define a birational version of the stability of cotangent sheaves for complex projective manifolds, and more generally for smooth orbifolds. We then show, using standard conjectures in birational classification, that these cotangent sheaves are birationally stable, unless the orbifold is uniruled.
Subseasonal extremes of precipitation and active‐break cycles of the Indian summer monsoon in a climate‐change scenario

Changes to the behaviour of subseasonal precipitation extremes and active‐break cycles of the Indian summer monsoon are assessed in this study using pre‐industrial and 2 × CO2 integrations of the Hadley Centre coupled model HadCM3, which is able to simulate the monsoon seasonal cycle reasonably. At 2 × CO2, mean summer rainfall increases slightly, especially over central and northern India. The mean intensity of daily precipitation during the monsoon is found to increase, consistent with fewer wet days, and there are increases to heavy rain events beyond changes in the mean alone. The chance of reaching particular thresholds of heavy rainfall is found to approximately double over northern India, increasing the likelihood of damaging floods on a seasonal basis. The local distribution of such projections is uncertain, however, given the large spread in mean monsoon rainfall change and associated extremes amongst even the most recent coupled climate models. The measured increase of the heaviest precipitation events over India is found to be broadly in line with the degree of atmospheric warming and associated increases in specific humidity, lending a degree of predictability to changes in rainfall extremes. Active‐break cycles of the Indian summer monsoon, important particularly due to their effect on agricultural output, are shown to be reasonably represented in HadCM3, in particular with some degree of northward propagation. We note an intensification of both active and break events, particularly when measured against the annual cycle, although there is no suggestion of any change to the duration or likelihood of monsoon breaks. Copyright © 2009 Royal Meteorological Society
Pre‐filter design for tracking error specifications in QFT

This note shows how the pre‐filter may be designed in quantitative feedback design of single‐input, single‐output systems with tracking error specifications (Eitelberg, Automatica, 2000; 36(2):319). The method uses gain and phase information for the pre‐filter design. The design is conveniently performed on the log polar complex plane using standard CAD tools. Copyright © 2003 John Wiley & Sons, Ltd.
Data driven chi-square test for uniformity with unequal cells

The power of Pearson's chi-square test for uniformity depends heavily on the choice of the partition of the unit interval involved in the form of the test statistic. We propose a selection rule which chooses a proper partition based on the data. This selection rule leads usually to essentially unequal cells well suited to the observed distribution. We investigate the corresponding data driven chi-square test and present a Monte Carlo simulation study. The conclusion is that this test achieves a high and very stable power for a large class of alternatives, and is much more stable than any other test we compare to.
Behavioural and Psychological Symptoms in Neurocognitive Disorders: Specific Patterns in Dementia Subtypes

Abstract Background Behavioural and psychological symptoms in dementia (BPSD) form an important sub-syndrome of dementia. We assessed the frequency and severity of BPSD in a random sample of Hungarian treatment-naïve dementia patients. Furthermore, we examined the relationship between cognitive symptoms and BPSD and the pattern of BPSD in specific types of dementias. Methods Patients (n=131) were classified into 3 groups: Alzheimer’s (AD), vascular (VD), and mixed (MD) dementia. The Mini-Mental State Examination (MMSE), Alzheimer’s Disease Assessment Scale-Cognitive Subscale (ADAS-Cog) and Neuropsychiatric Inventory (NPI) neuropsychological tests were employed. Results Mean age and MMSE score did not differ significantly among groups. BPSD was frequent (100% prevalence, NPI mean total Frequency score: 14.58, SD=7.55); abnormal motor behaviour showed the highest frequency. Hallucinations and delusions were related to the aetiology of dementia and were independent of the level of cognitive deterioration, whereas irritability, sleep-wake cycle dysfunctions, and eating-appetite change were associated with cognitive deterioration and were independent from aetiology. Both aberrant motor behaviour and disinhibition were significantly associated with aetiology and cognitive deterioration. Conclusions BPSD symptoms are significant constituents of dementia syndromes, affecting quality of life and substantially contributing to the caregiver’s burden. Specific symptom patterns can be identified in different types of dementia.
Non-finitely generated relatively hyperbolic groups and Floyd quasiconvexity

The paper consists of two parts. In the first one we show that a relatively hyperbolic group $G$ splits as a star graph of groups whose central vertex group is finitely generated and the other vertex groups are maximal parabolic subgroups. As a corollary we obtain that every group which admits 3-discontinuous and 2-cocompact action by homeomorphisms on a compactum is finitely generated with respect to a system of parabolic subgroups. The second part essentially uses the methods of topological entourages developed in the first part. Using also Floyd metrics we obtain finer properties of finitely generated relatively hyperbolic groups. We show that there is a system of "tight" curves satisfying the property of horospherical quasiconvexity. We then prove that the Floyd quasigeodesics are tight and so the parabolic subgroups of $G$ are quasiconvex with respect to the Floyd metrics. As a corollary we obtain that the preimage of a parabolic point by the Floyd map is the Floyd boundary of its stabilizer.
Self‐consistent radial sheath

The boundary layer arising in the radial vicinity of a tokamak limiter is examined, with special reference to the TEXT tokamak [Nucl. Fusion 27, 1125 (1987); Phys. Fluids 27, 2956 (1984)]. It is shown that sheath structure depends upon the self‐consistent effects of ion guiding‐center orbit modification as well as the radial variation of E×B‐induced toroidal rotation. Reasonable agreement with experiment is obtained from an idealized model, which, however simplified, preserves such self‐consistent effects. It is argued that the radial sheath, which occurs whenever confining magnetic field lines lie in the plasma boundary surface, is an object of some intrinsic interest. It differs from the more familiar axial sheath because magnetized charges respond very differently to parallel and perpendicular electric fields.
QUANTILE PERIODOGRAM AND TIME‐DEPENDENT VARIANCE

This article investigates the statistical properties of the recently introduced quantile periodogram for time series with time‐dependent variance. The asymptotic distribution of the quantile periodogram is derived in the case where the time series consists of i.i. d. random variables multiplied by a time‐dependent scale parameter. It is shown that the time‐dependent variance is represented approximately additively in the mean of the asymptotic distribution of the quantile periodogram. It is also shown that the strength of the representation is proportional to the squared quantile of the i.i. d. random variables, so that a stronger characterization is expected at upper and lower quantile levels if the time series is centred at zero. These properties are further demonstrated by simulation results. The series of daily returns from the Dow Jones Industrial Average, which is known to exhibit heteroscedastic volatility, serves to motivate the investigation.
Advancement of Algebraic Function Approximation in Eigenvalue Problems of Lossless Metallic Waveguides to Infinite Dimensions, Part I: Properties of the Operator in Infinite Dimensions

In an attempt to advance finite dimensional algebraic function approximation technique in eigenvalue problems of lossless metallic guides filled with anisotropic and/or inhomogeneous media, to exact analysis in infinite dimensions, properties of the linear operator in infinite dimensions corresponding to Maxwell's equations, are investigated. Some function theoretic aspects of this operator formalism for guidance phenomenon are discussed. It is found that this operator can be considered bounded and holomorphic. If not, because of poles the medium constituent matrices ε and μ may have, its inverse, which will be bounded and holomorphic, can be used to assess propagation constant behavior in the neighborhood of the singularity.
Ordered group reference priors with application to the multinomial problem

SUMMARY Noninformative priors are developed, using the reference prior approach, for multiparameter problems in which there may be parameters of interest and nuisance parameters. For a given grouping of parameters and ordering of the groups, intuitively, according to inferential importance, an algorithm for determining the associated reference prior is presented. The algorithm is illustrated on the multinomial problem, with discussion of the variety and success of various groupings and ordering strategies.
Extending Ring Topologies

Throughout this abstract, (R,T) denotes a compact (Hausdorff) topological ring. The authors extend T to ring topologies on R which are totally bounded or even pseudocompact; a principal tool is the Bohr compactification of a topological ring. They show inter alia: If the Jacobson radical J(R) of R satisfies w(R/J(R)) > ω then there is a pseudocompact ring topology on R strictly finer than T; if in addition w(R) = w(R/J(R)) = α with cf(α) > ω then there are exactly 22|R|-many such topologies. The ring (R,T) is said to be a van der Waerden ring if T is the only totally bounded ring topology on R. Theorem 4.13 asserts that if R is semisimple, then R is a van der Waerden ring if and only if in the Kaplansky representation R = Πn < ω(Rn)αn of R as a product of full matrix rings over finite fields each αn is finite. Other classes of van der Waerden rings are constructed, and it is shown that there are non-compact totally bounded rings (S,U) such that U is the only totally bounded ring topology on S.