Miracle-dz/UniFAR-FTUs huggingface dataset:
A parameterization scheme for non-convective condensation including prediction of cloud water content

A model for non-convective condensation processes has been developed. The model allows condensation to begin before relative humidity reaches 100%. The liquid water content of clouds is a prognostic variable of the model. The rate of condensation is a function of relative humidity and moisture flux convergence. The micro-physical processes involved in the formation of clouds and precipitation are parameterized by assuming that the rate of precipitation formation is a function of the amount of cloud water. Evaporation from falling rain is taken into account. Quantitative tests with the model indicated that it yields reasonable evolution times and water content of clouds, and gives reasonable precipitation amounts.
Nested Reduced-Rank Autoregressive Models for Multiple Time Series

Abstract The nested reduced-rank autoregressive (AR) model is considered in order to simplify and provide a more detailed description of the structure of the multivariate time series and to reduce the number of parameters in the time series modeling. The multivariate AR model is Yt = Σ p j=1 Φ j Y t-j + et , where Yt is m × 1, and the structure of the model considered is such that the rj = rank(Φ j ) are nonincreasing as the lag j increases, so the Φ j have the factorization Φ j = AjBj and range(Aj ) ⊃ range(A j+1). Specification of the coefficient rank structures for such models through the use of canonical correlation analysis between Yk,t = [Y′t, …, Y′t-k ]′ and Y k,t-1 is discussed. A canonical variable transformation that produces simpler structure in the model and explicitly illustrates how different components of the vector series depend on past lagged values to differing degrees is also examined. A Gaussian parameter-estimation procedure is described and asymptotic properties of the Gaussian estim.
Interplanetary scintillations of PSR 0531+21 at 74 MHz

The flux density of the 74 MHz compact source in the Crab Nebula is estimated from interplanetary scintillation observations using a new method of analysis. The result removes the earlier disagreement with very-long-baseline interferometry determinations. It also shows a 45% secular decrease in the flux from 1971.4 to 1975.4, in good agreement with observations of the 74 MHz pulsing flux. The differences between this new analysis and the method which had been used to date are described. A procedure for the reinterpretation of other meter-wavelength scintillation observations is discussed.
Deep Near-Infrared Images and ISOCAM Observations of Chamaeleon I North

We present the results of deep near-infrared imaging and ISOCAM observations of three selected regions localized in the northern part of the Chamaeleon I dark cloud, in order to search for the low-luminosity population. In an area of 3 × 3 arcmin2 centered on the bipolar molecular outflow, which is the densest part of the cloud, we have discovered a new Class I source (here named ISOCAM–Cha INa2) with a spectral index α = 1.9 and 1–18 μm luminosity of 0.6 L⊙ that is most probably responsible for the observed CO outflow. The comparison between the observed K-magnitude distribution for this region and that obtained for a region outside the outflow and adjacent to the star HD 97300 indicates the possible presence of a very low luminosity young stellar population in the densest part of the cloud.
Constructal optimisation of heat generating volumes

Cooling of electronics by conduction with high thermal conductivity paths located in heat generating, low conductivity volumes are investigated using constructal theory. A new mathematical solution for the fundamental problem of how to collect and channel to one point the heat generated volumetrically in a low conductivity volume of a given size is developed using the Lagrange Multiplier Method. Additionally, at the fundamental step, the optimisation procedure is exact. No approximation has been made about the geometrical characteristics of the fundamental element. In solutions of the fundamental elements, the amount of high conductivity material (high conductivity paths) through the volume is fixed.
Univariate and Multivariate Assimilation of AIRS Humidity Retrievals with the Local Ensemble Transform Kalman Filter

Abstract This study uses the local ensemble transform Kalman filter to assimilate Atmospheric Infrared Sounder (AIRS) specific humidity retrievals with pseudo relative humidity (pseudo-RH) as the observation variable. Three approaches are tested: (i) updating specific humidity with observations other than specific humidity (“passive q”), (ii) updating specific humidity only with humidity observations (“univariate q”), and (iii) assimilating the humidity and the other observations together (“multivariate q”). This is the first time that the performance of the univariate and multivariate assimilation of q is compared within an ensemble Kalman filter framework. The results show that updating the humidity analyses by either AIRS specific humidity retrievals or nonhumidity observations improves both the humidity and wind analyses. The improvement with the multivariate-q experiment is by far the largest for all dynamical variables at both analysis and forecast time, indicating that the interaction between the s.
Propeller Rotation Noise Due to Torque and Thrust

Sound pressures of the first four harmonics of rotation noise from a full‐scale two‐blade propeller were measured and comparison is made with values calculated from theory. The comparison is made (1) for the space distribution at constant tip speed, and (2) for fixed space angles with variable tip speed. A relation for rotation noise from an element of radius due to Gutin is extended to cover the entire propeller disk. Curves are given showing the effect of number of blades on the rotation noise.
Plasmonic silicon solar cells using titanium nitride: a comparative study

Abstract. Plasmonic materials, especially silver, are widely used to increase efficiency of solar cells due to their ability to localize the light in nanoscale. This tight confinement increases the absorption of a thin film solar cell. However, these materials are expensive and increase the cost/watt of the solar cell. Thus, finding an abundant and cheap material with a comparable plasmonic effect can dramatically reduce solar cell cost by enabling the use of ultrathin active layers. In this work, we investigate TiN as an alternative cheap and abundant plasmonic material. TiN is also more CMOS compatible. Several TiN plasmonic solar cell configurations are studied and analyzed. These studies show that the TiN plasmonic solar cell has a comparable performance for back side plasmonic configuration.
On algorithmic hypergraph regularity

On Algorithmic Hypergraph Regularity By Annika Poerschke Thomason and Chung, Graham and Wilson were the first to systematically study quasi-random graphs and hypergraphs and showed that several properties of random graphs imply each other in a deterministic sense. In particular, they showed that ε-regularity from Szemerédi’s regularity lemma is equivalent to their concepts. Over recent years several hypergraph regularity lemmas were established. In this dissertation, we focus on two regularity lemmas for 3-uniform hypergraphs one due to Gowers, and one due to Haxell, Nagle, and Rödl. Their lemmas are based on different notions of quasirandom hypergraphs and we show that their concepts are in fact equivalent. Since the regularity lemma of Haxell, Nagle, and Rödl is algorithmic, we also obtain an algorithmic version of Gowers’ regularity lemma. Further, we use Gowers’ analytic approach to the hypergraph regularity lemma to give a more direct proof of the algorithmic version of his regularity lemma. On Algorithmic Hypergraph Regularity
Estimating a survival function with doubly censored data in a proportional hazard model

This article presents a non-parametric estimator of a survival function in a proportional hazard model when some of the data are censored on the left and some are censored on the right. The proposed method generalizes the work of Ebrahimi (1985). Uniformly strong consistency and asymptotic normality of the estimator are proved. A computer simulation study is presented to analyse the behaviour of the estimator when model assumptions fit the data and when they do not fit.
The starting process in a hypersonic nozzle

This paper describes an experimental study of the starting process in a reflected-shock tunnel, and compares the results with numerical calculations reported previously (Smith 1962). It is shown that an unsteady expansion wave dominates the transient flow, and the shock-wave system plays a minor role. The effects of initial pressure in the nozzle were investigated, and the behaviour of the secondary shock wave was noted. It was found that initial pressures larger even than the steady-flow static pressure can be tolerated without prolonging the starting process, despite the presence of a strong secondary shock wave. Other analyses, based on the ‘steady-state’ model of the starting process, are discussed and shown to give an unrealistic description of the flow field.
High-order expansions in the quasi-neutral limit of the Euler–Poisson system for a potential flow

We are interested in the steady-state Euler–Poisson system for a potential flow used in the mathematical modelling of plasmas and semiconductors. In the case of the quasi-neutral limit, boundary layers can appear. We study this limit by using an asymptotic expansion. We show the existence and uniqueness of each profile and give the justification of the asymptotic expansion up to any order.
PLANETARY-SCALE STRONTIUM ISOTOPIC HETEROGENEITY AND THE AGE OF VOLATILE DEPLETION OF EARLY SOLAR SYSTEM MATERIALS

Isotopic anomalies in planetary materials reflect both early solar nebular heterogeneity inherited from presolar stellar sources and processes that generated non-mass-dependent isotopic fractionations. The characterization of isotopic variations in heavy elements among early solar system materials yields important insight into the stellar environment and formation of the solar system, and about initial isotopic ratios relevant to long-term chronological applications. One such heavy element, strontium, is a central element in the geosciences due to wide application of the long-lived 87Rb–87Sr radioactive as a chronometer. We show that the stable isotopes of Sr were heterogeneously distributed at both the mineral scale and the planetary scale in the early solar system, and also that the Sr isotopic heterogeneities correlate with mass-independent oxygen isotope variations, with only CI chondrites plotting outside of this correlation. The correlation implies that most solar system material formed by mixing of at least two isotopically distinct components: a CV-chondrite-like component and an O-chondrite-like component, and possibly a distinct CI-chondrite-like component. The heterogeneous distribution of Sr isotopes may indicate that variations in initial 87Sr/86Sr of early solar system materials reflect isotopic heterogeneity instead of having chronological significance, as interpreted previously. For example, given the differences in 84Sr/86Sr between calcium aluminum inclusions and eucrites (ε84Sr > 2), the difference in age between these materials would be ∼6 Ma shorter than previously interpreted, placing the Sr chronology in agreement with other long- and short-lived isotope systems, such as U–Pb and Mn–Cr.
A Variational Approach to the Theory of the Effective Magnetic Permeability of Multiphase Materials

Variational theorems are established and applied to the derivation of bounds for the effective magnetic permeability of macroscopically homogeneous and isotropic multiphase materials. For reasons of mathematical analogy the results are also valid for the dielectric constant, electric conductivity, heat conductivity, and diffusivity of such materials. For the case of two‐phase materials, the bounds derived are the most restrictive ones that can be given in terms of the phase permeabilities and volume fractions. Comparison of present theoretical results with existing experimental data shows good agreement.
Chaos in classical and quantum mechanics

Contents: Introduction. - The Mechanics of Lagrange. - The Mechanics of Hamilton and Jacobi. - Integrable Systems. - The Three-Body Problem: Moon-Earth-Sun.- Three Methods of Section. - Periodic Orbits. - The Surface of Solution. - Models of the Galaxy and of Small Molecules. - Soft Chaos and the KAM Theorem. - Entropy and Other Measures of Chaos. - The Anisotropic Kepler Problem. - The Transition From Classical to Quantum Mechanics. - The New World of Quantum Mechanics. - The Quantization of Integrable Systems. - Wave Functions in Classically Chaotic Systems. - The Energy Spectrum of a Classically Chaotic System. - The Trace Formula. - The Diamagnetic Kepler Problem. - Motion on a Surface of Constant Negative Curvature. - Scattering Problems, Coding and Multifractal Invariant Measures. - References. - Index.
Reduced-order unsteady aerodynamic models at low Reynolds numbers

Abstract In this paper we develop reduced-order models for the unsteady lift on a pitching and plunging aerofoil over a range of angles of attack. In particular, we analyse the pitching and plunging dynamics for two cases: a two-dimensional flat plate at $\mathit{Re}= 100$ using high-fidelity direct numerical simulations and a three-dimensional NACA 0006 aerofoil at $\mathit{Re}= 65\hspace{0.167em} 000$ using wind-tunnel measurements. Models are obtained at various angles of attack and they are verified against measurements using frequency response plots and large-amplitude manoeuvres. These models provide a low-dimensional balanced representation of the relevant unsteady fluid dynamics. In simulations, flow structures are visualized using finite-time Lyapunov exponents. A number of phenomenological trends are observed, both in the data and in the models. As the base angle of attack increases, the boundary layer begins to separate, resulting in a decreased quasi-steady lift coefficient slope and a delayed relaxation to steady state at low frequencies. This extends the low-frequency range of motions that excite unsteady effects, meaning that the quasi-steady approximation is not valid until lower frequencies than are predicted by Theodorsen’s classical inviscid model. In addition, at small angles of attack, the lift coefficient rises to the steady-state value after a step in angle, while at larger angles of attack, the lift coefficient relaxes down to the steady-state after an initially high lift state. Flow visualization indicates that this coincides with the formation and convection of vortices at the leading edge and trailing edge. As the angle of attack approaches the critical angle for vortex shedding, the poles and zeros of the model approach the imaginary axis in the complex plane, and some zeros cross into the right half plane. This has significant implications for active flow control, which are discussed. These trends are observed in both simulations and wind-tunnel data.
Improved estimation for temporally clustered extremes

In this paper, we investigate the effects of declustering applied to sequences of extreme observations. Through a simulation study, we demonstrate that the common practice of analysing peaks over thresholds (POT) is liable to incur serious bias in the estimation of parameters, as well as the return levels used as design specifications when building to withstand extremes of wind or rain, or river or sea level. We demonstrate that a much simpler approach, the direct analysis of all exceedances of a high threshold, can reduce this bias to negligible levels. This approach has, until now, been unpopular, because the data being analysed are not independent. The effect of this is to cause the standard errors associated with parameter estimates to underestimate the uncertainty attached to these estimates. We employ existing but little‐used methodology to inflate these standard errors, and we demonstrate that the adjusted values are very good representations of the true uncertainty associated with maximum likelihood estimates. The overall approach has thus achieved the effect of eliminating the bias in estimation, while accounting for any undesirable effects caused by dependent data.
Physical Correlates of Brass‐Instrument Tones

Time‐dependent Fourier analyses of the attack transients and steady states of about 900 trumpet, trombone, tuba, and French‐horn tones yielded the amplitudes and relative phases of the first 11 partials. Relative component amplitudes for all tones of an instrument played at a given dynamic marking are approximately described by a spectral envelope. The partials are conveniently divided into those below a cutoff frequency (Class 1 components) common to all notes of the instrument and those above it (Class 2). Class 1 components have similar attack envelopes and reach approximately equal steady‐state values before those in Class 2. The transient periods for Class 2 components increase with frequency of the components, and their steady‐state values decrease rapidly with increasing frequency of the components. Amplitude modulations (blips) that last for one or only a few cycles of the modulation occur for all components during the end of the transient, but are larger for Class 2 components. For brasses other .
Nanostructured metallic cores with extremely low loss and controlled permeability

Magnetic anisotropy perpendicular to the ribbon axis was induced in nanocrystalline FeCuNbSiB ribbons by crystallization under tensile stress, and the relative permeability of the ribbon was approximately 250. Toroidal cores for a choke coil were prepared from the ribbons. The magnetic loss decreased with increasing the core diameter and it was found that deterioration of magnetic properties due to formation of a toroidal core was suppressed by making the core diameter larger than the critical diameter determined from the values of magnetostriction and induced anisotropy. As a result, toroidal cores-with extremely low loss were achieved. The permeability of the cores developed was kept constant up to 1 MHz and their magnetic loss was much smaller than the loss values reported previously for nanostructured and amorphous cores with low permeability. The measured magnetic loss agreed with the calculated classical eddy current loss. In addition, the permeability and magnetic loss were kept constant up to the dc bias field, being three times higher than that applicable to a ferrite cut core with the same permeability value.
PION - NUCLEON PARTIAL WAVE ANALYSIS

We have carried out a partial-wave analysis of amalgamated pion-nucleon scattering data at 35 momenta in the range 0.429--1.995 GeV/c. At each momentum, a large set of fits was obtained, with the amplitude represented as the sum of a fixed background and the fitted terms of an accelerated convergence expansion. The effects of discrete and continuum ambiguities were separated by special statistical and numerical techniques which sort the fits into clusters. Dispersion relations on selected curves within the kinematical region for physical scattering were used to resolve the ambiguities and to derive constraints. These constraints, which ensure that the fitted amplitudes have a relatively smooth energy dependence consistent with analyticity, were used iteratively to arrive at a unique set of amplitudes which fit the scattering data throughout the energy region studied.
Reduced-order estimation of nonstationary flows with electrical impedance tomography

In this paper, we consider the simultaneous reconstruction of a nonstationary concentration distribution and the underlying nonstationary flow field. As the observation modality, we employ electrical impedance tomography. Earlier studies have shown that such an estimation scheme is in principle possible since the evolution of an inhomogeneous concentration carries information also on the velocity field. These results have, however, been restricted to either stationary velocity fields or simplified non-physical models. In the general case, the estimation of the velocity field up to the fine details of the flow with diffuse tomography is impossible. In this paper we show, however, that it is possible to estimate a reduced-order representation of a physical fluid dynamics model, here the Navier–Stokes model, simultaneously with the concentration. This is accomplished by considering a proper orthogonal decomposition representation for the velocity field, and careful modelling of the uncertainties of the models, in particular, the subspace of the velocity field that is not estimated. We assess the approach with two numerical examples in which a projection of a vortex flow is reconstructed.
Characteristics of Taylor vortex structure in combined axial and rotating flow

The sequential form of the axial displacement of inclined Taylor vortices and their progressive degeneration to horizontal streaks due to the increasing dominance of axial flow is demonstrated via an analytical indicator-based direct flow visualization technique applied to a concentric cylinder cell with the inner cylinder rotating. Cette communication decrit le decalage sequentiel axial des tourbillons de Taylor inclines, ces derniers se desagregeant a la fin en de striures horizontales a la mesure de la domination du debit axial. Le phenomene est manifeste au moyen de visualisation basee sur les indicateurs colores dans une cellule a cylindres coaxiaux, le cylindre interieur etant tourne.
General approximation theorem on feedforward networks

We show that standard feedforward neural networks with as few as a single hidden layer and arbitrary bounded nonlinear (continuous or noncontinuous) activation functions which have two unequal limits in infinities can uniformly approximate (in contrast to approximate measurably) arbitrary bounded continuous mappings on R/sup n/ with any precision. Especially, in a compact set of R/sup n/, standard feedforward neural networks with as few as a single hidden layer and arbitrary bounded nonlinear (continuous or noncontinuous) activation functions can uniformly approximate arbitrary continuous mappings with any precision. These results also hold for multi-hidden layer standard feedforward neural networks. We found that the boundedness and unequal limits at infinities conditions on the activation functions are sufficient, but not necessary.
Inverse aeroacoustic problem for a streamlined body. II - Accuracy of solutions

Previously established methods for performing the aeroacoustic inversion for a fiat-plate airfoil are tested to determine their sensitivity to errors in both the far-field input data and the mean-flow input parameters. The results of the sensitivity analysis for the input data show that the magnification of input error due to ill-posedness can be controlled by optimal choices of the regularization parameter and the input data locations. A similar sensitivity analysis of the effect of mean-flow parameters-Mach number and reduced frequency-shows strong dependence of the inverse process on these parameters. In this case, improvements in the reconstructions can be obtained by using input data from the midfield.