Miracle-dz/UniFAR-FTUs huggingface dataset:
Thrust-Aided Librating Deployment of Tape Tethers

This paper addresses issues relevant to the deployment operations of a multikilometer tape-shaped tether from an orbiting spacecraft with the aid of an inline low-thrust propulsion system located inside the tip mass to be deployed. The study is part of a technology development project of an end-of-life deorbiting device for debris mitigation that uses an electrodynamic tether to produce a drag force according to the Lorenz law. The tether must be deployed from a nontumbling satellite with a swinging maneuver that follows a predetermined trajectory. A suitable set of reference trajectories was found by means of a numerical nonlinear optimization using the Nelder–Mead algorithm for tethers of different lengths. Each reference trajectory is fed forward to a proportional-derivative closed-loop brake control system integrated in the tether deployer. A sensitivity analysis was carried out to pinpoint the reference trajectories that minimize the residual libration at the end of the deployment, thus providing the.
Crucial flow stabilization and multiple instability branches of gravity-driven films over topography

In this paper, we present experimental results on the linear instability of gravity-driven viscous films flowing down a strongly undulated incline. To systematically investigate the relation between the eddies which form in the troughs of sufficiently steep undulations and the corresponding stability maps, we vary the liquid's viscosity experimentally. We report on a rich variety of phenomena, which is provoked by the corrugation of the underlying substrate, including: (a) transitions from long-wave to short-wave type instability, (b) a disjoining of the instability branches leading to formation of isles in the stability map, (c) flow destabilization, but also, (d) very strong stabilization of the flow up to a factor of two for arbitrary linear disturbances and even up to a factor of four for linear short-wave disturbances. To our knowledge, this is the first experimental work, which reports on any of these phenomena for gravity-driven liquids flowing down an undulated incline. Since structured substrates.
Aluthge Transforms and the Convex Hull of the Eigenvalues of a Matrix

The Aluthge transform of a matrix is observed from the standpoint of smoothing process toward normality. We prove that every limiting point (matrix) of iterated Aluthge transforms is a normal matrix, and consequently the intersection of the numerical ranges of all iterated Aluthge transforms coincides with the convex hull of the eigenvalues of T. We prove further that the numerical range of T coincides with the convex hull of its eigenvalues if and only if T and Δ (T) have the same numerical range.
Bayesian analysis of longitudinal ordered data with flexible random effects using McMC: application to diabetic macular Edema data

In the analysis of correlated ordered data, mixed-effect models are frequently used to control the subject heterogeneity effects. A common assumption in fitting these models is the normality of random effects. In many cases, this is unrealistic, making the estimation results unreliable. This paper considers several flexible models for random effects and investigates their properties in the model fitting. We adopt a proportional odds logistic regression model and incorporate the skewed version of the normal, Student's t and slash distributions for the effects. Stochastic representations for various flexible distributions are proposed afterwards based on the mixing strategy approach. This reduces the computational burden being performed by the McMC technique. Furthermore, this paper addresses the identifiability restrictions and suggests a procedure to handle this issue. We analyze a real data set taken from an ophthalmic clinical trial. Model selection is performed by suitable Bayesian model selection criteria.
Emission lines from X-ray-heated accretion disks in low-mass X-ray binaries

We investigate the structure of accretion disks illuminated by X-rays from a central compact object in a binary system. X-rays can photoionize the upper atmosphere of the disk and form an accretion disk corona (ADC) where emission lines can form. We construct a model to calculate the vertical structure and the emission spectrum of the ADC with parameters appropriate to low-mass X-ray binaries. These models are made by nonlocal thermodynamic equilibrium calculations of ion and level populations and include a large number of atomic processes for 10 cosmically abundant elements. Transfer of radiation is treated by using the escape probability formalism. The vertical temperature profile of the ADC consists of a Compton-heated region and a mid-T zone where the temperature is approximately 10(exp 6) K. A thermal instability occurs close to the disk photosphere and causes the temperature of the ADC to drop abruptly from 10(exp 6) K to several times 10(exp 4) K. The emission spectrum in the optical, ultraviolet, extreme ultraviolet, and X-ray range is discussed and compared with the observations.
DETERMINATION OF MOMENTUM TRANSFER AND INELASTIC COLLISION CROSS SECTIONS FOR ELECTRONS IN NITROGEN USING TRANSPORT COEFFICIENTS.

Abstract : Momentum transfer and inelastic collision cross sections for electrons in N2 were obtained from electron transport coefficients for values of the electron energy between about 0.003 and 30 eV. The cross sections for vibrational excita tion are consistent with those of Schulz provided the sum total cross section is normalized to 5.5 x 10 to the-16th power sq cm at 2.2 eV. Furthermore, a tail extending down to the threshold of 0.29 eV is postulated for the v = 1 vibrational level. Electronic excitation is approximated by a set of six effective cross sections which, for the most part, are consistent with previous results. The ionization cross section of Tate and Smith was used. The mean energy of electrons in N2 subjected to high frequency ac electric fields is found to be single valued function of the electric field E divided by the ac radian frequency, although there are regions of E/radian frequency where the mean energy increases extremely rapidly with E/radian frequency. (Author)
The abundance distribution in the inner spheroid.

We present the metallicity distribution perpendicular to the Galactic plane, to distances of order 2 kpc. This has been derived by comparison of new photometry and existing spectroscopic samples of stars in situ and local samples of kinematically selected stars. These data may be used to constrain the enrichment history of the inner spheroid, where an intermediate component apparently dominates. The metallicity distribution we find is best characterized by a sum of three independent components, each with a well-defined mean abundance and little or no gradient in this mean, but with very different spatial density distributions. These components are identified as the Galactic thin disk, the young stars of which have mean abundance approx.((Fe/H))approx. =+0.0, sigma/sub /approx. =0.15, and (exponential) scale height approx. =100 pc, while the older stars have mean abundance approx.((Fe/H))approx. =-0.3, sigma/sub /approx. =0.2 and (exponential) scale height approx. =300 pc; the Galactic thick disk, with mean abundance approx.((Fe/H))approx. =-0.6, sigma/sub /approx. =0.3 and (exponential) scale height > or approx. =1 kpc; and the Galactic extreme spheroid, with mean abundance approx.((Fe/H)) approx. =-1.5, sigma/sub /approx. =0.5 and (exponential) scale height > or approx. =4 kpc, consistent with an R/sup 1//sup ///sup 4/ law distribution. The relative numbermore » of stars in the solar vicinity in each of these populations are very approximately 0.2 : 1.0 : 0.02 : 0.001 for the young disk, the old disk, thick disk, and spheroid, respectively. « less
Gap size effects on centrifugally and rotationally driven instabilities

The rotation effects on centrifugally driven instabilities in curved channel flow with a finite gap are investigated. An inviscid criterion of stability is formulated to explain the behavior of the flow when rotation and curvature effects compete to either stabilize or destabilize the flow. The stability of curved Poiseuille flow with finite gap size is studied, and it is shown that the asymmetry between the directions of rotation is enhanced when the gap size increases.
Explicit asymptotic formulas for the positions, widths, and strengths of resonances in Mie scattering

Explicit asymptotic formulas are derived for the positions, widths, and strengths of the morphology-dependent resonances in Mie scattering. These formulas are compared with numerical data and found to be highly accurate, especially for the low-order resonances most relevant to nonlinear processes. They permit the interpretation of experimental data on light scattering from microdroplets without resorting to the full apparatus of the Mie scattering formalism.
Functional clustering and identifying substructures of longitudinal data

Summary. A functional clustering (FC) method, k‐centres FC, for longitudinal data is proposed. The k‐centres FC approach accounts for both the means and the modes of variation differentials between clusters by predicting cluster membership with a reclassification step. The cluster membership predictions are based on a non‐parametric random‐effect model of the truncated Karhunen–Loève expansion, coupled with a non‐parametric iterative mean and covariance updating scheme. We show that, under the identifiability conditions derived, the k‐centres FC method proposed can greatly improve cluster quality as compared with conventional clustering algorithms. Moreover, by exploring the mean and covariance functions of each cluster, thek‐centres FC method provides an additional insight into cluster structures which facilitates functional cluster analysis. Practical performance of the k‐centres FC method is demonstrated through simulation studies and data applications including growth curve and gene expression profile data.
Conductivity and permeability of rocks

The electrical conductivity of salt-water-saturated rocks is modeled by a random resistance network which has a zero percolation threshold. The porosity is varied by a random bond-shrinkage mechanism. Numerical and analytical calculations of the model in different dimensions show an Archie's-law behavior: ${\ensuremath{\sigma}}_{r}=a{\ensuremath{\sigma}}_{w}{\ensuremath{\varphi}}^{m}$, where $\ensuremath{\varphi}$ is the porosity of the rock, and ${\ensuremath{\sigma}}_{r}$ and ${\ensuremath{\sigma}}_{w}$ are the conductivities of the rock and water, respectively. We find that the Archie's exponent $m$ is always greater than unity and is related to the skewness of the "pore-size distribution" of the rock. Applying the same model to fluid-flow permeability (${k}_{r}$) gives ${k}_{r} \ensuremath{\propto}{\ensuremath{\varphi}}^{{m}^{\ensuremath{'}}}$, where ${m}^{\ensuremath{'}}=m(m+1)$ in one dimension, and ${m}^{\ensuremath{'}}=2m$ in higher dimensions. This power-law form is consistent with the well-known Kozeny equation and has been frequently suggested by empirical studies. Experimental tests of the model are performed on artificial rocks, made by fusing small glass beads, as well as real rocks. From resistivity measurements, we demonstrate that $m$ is larger in samples with a wider fluctuation of pore sizes, which is qualitatively consistent with the model. From fluid-flow experiments on fused glass beads, we find quantitative support for the ${m}^{\ensuremath{'}}=2m$ prediction.
Relativistic electron scattering by electrostatic upper hybrid waves in the radiation belt

[ 1] Observations of particle precipitation into the Earth's atmosphere performed on low-altitude satellites have excited substantial interest in relativistic electron precipitation bursts from the outer zone of the radiation belt. As underlying mechanism of such bursts, we suggest particle scattering into the loss cone due to higher-order cyclotron resonance interaction between relativistic electrons and intense narrow-band upper hybrid waves, which are frequently observed outside the plasmapause. The case of a single wave and the case of a wide wave number spectrum are considered, and approximate expressions for the relativistic particle diffusion coefficients in phase space are calculated for conditions of an inhomogeneous plasma. It is found that relativistic electrons have a preference over lower-energy electrons from the viewpoint of the number of cyclotron resonances that a particle crosses during each bounce period. Owing to the predominantly longitudinal direction of the upper hybrid wave group velocity, the resonant wave-particle interaction can take place over many electron bounce periods, which facilitates the particle scattering into the loss cone. The theory developed in the present paper accounts for two main features of the relativistic electron precipitation bursts, namely, a strong energy dependence in the electron precipitation process and the small-scale burst structure, which is primarily attributed to the localization and strong inhomogeneity of the growth region of the upper hybrid modes responsible for the scattering. The existence of intrinsic temporal structure of the precipitation on timescales comparable to the bounce period is also consistent with the theory due to the high efficiency of the scattering process.
Explicit solution and eigenvalue bounds in the Lyapunov matrix equation

An explicit solution to the algebraic Lyapunov matrix equation is obtained in terms of the controllability matrix of the pair of coefficient matrices. This enables us to determine the number of positive eigenvalues of the positive semidefinite solution through the controllability matrix. Based on this explicit formula, upper and lower bounds for each eigenvalue of the solution are derived, which always give nontrivial estimates.
A FIELD SURVEY ON EFFECTS OF EXPOSURE TO NOISE AND VIBRATION FROM RAILWAY TRAFFIC, PART I: ANNOYANCE AND ACTIVITY DISTURBANCE EFFECTS

Abstract The paper presents some of the results from field investigations on effects of exposure to noise and vibration from railway traffic. Effects on annoyance, sleep disturbances and psycho-social well-being, as well as disturbance of different activities, were evaluated by a postal questionnaire. Effects on sleep and psycho-social well-being will be presented in a second paper. Fifteen different sites located near railway lines in Sweden were investigated. The study covered areas with different number of trains per 24 hours in areas with strong vibration exceeding 2 mm/s, caused by the railway traffic, as measured in the buildings, as well as areas without vibration, or with vibration weaker than 1 mm/s; 2833 persons between 18 and 75 years of age participated in the study. The results show that railway noise is experienced as more annoying in areas in which there is simultaneous exposure to vibration from railway traffic. Disturbance of communication was the most frequently mentioned annoyance reaction, outside and inside the dwellings, especially in areas with a high number of trains per 24 hours. To ensure an acceptable environmental quality where less than 5% of the exposed population is rather or very annoyed by railway noise, these noise levels must be below 80 dB L Amax and below 55 L eq respectively in areas without vibration. In areas with simultaneous exposure to strong vibration, actions against vibration or a greater distance between the houses and the railway line is needed, corresponding to a 10 dB(A) lower noise level than in areas without vibration.
The diffraction of dipole sound by the edge of a rigid baffle

The theory of the diffraction of dipole radiation by a half‐plane [M. Yildiz and O.K. Marwardi, J. Acoust. Soc. Am. 32, 1685 (1960)] has been much used in aeroacoustics work. There has been little experimental work done on the problem however. We place a small speaker near a half‐plane and find an angular distribution which confirms the theory. The half‐plane in effect splits the dipole so that the radiation in its direction is enhanced. [Partially supported by NASA‐Ames. ]
The Predicted Abundances of Deuterium-bearing Gases in the Atmospheres of Jupiter and Saturn

The first set of comprehensive thermochemical equilibrium and chemical kinetic calculations on the chemistry of deuterium-bearing gases in the deep atmospheres of Jupiter and Saturn is presented. The sensitivity of the results to variations in elemental and isotopic abundances is studied. Isotopic fractionation effects in the C-13/C12, N-15/N-14, and O-18/O-16 ratios in nonequilibrium species such as CO, CO/sub 2/, HCN, and N/sub 2/ are briefly considered. 125 references.
Spatial unmasking of nearby pure‐tone sources in a simulated anechoic environment

Spatial unmasking of nearby pure‐tone sources masked by broadband noise was studied in a simulated anechoic environment. The predicted amount of binaural unmasking was calculated using interaural differences from a spherical‐head model [B. G. Shinn‐Cunningham, S. G. Santarelli, and N. Kopco, J. Acoust. Soc. Am. (in press)] and the Colburn model of binaural processing [H. S. Colburn, J. Acoust. Soc. Am. 61, 525–533 (1977)]. Predictions were generated for several spatial configurations of signal and masker in the horizontal plane (varying target and masker azimuthal positions and distances) and for multiple tone frequencies. Predictions were compared with behaviorally measured detection thresholds obtained with headphone simulations using individually measured HRTFs. Results show that changes in detection threshold for free‐field signals are dominated by monaural effects due to large interaural level differences. Overall, spatial unmasking effects are very large for nearby sources due to simple energy effects at the better ear. Binaural unmasking is observable only for a subset of spatial configurations where the energy of signal and/or noise at both ears is sufficient to allow binaural processing, and even for these configurations the effect is generally weaker than that observed with distant sources. [Work supported in part by AFOSR Grant F49620‐98‐1‐0108. ]
Effects of roughness orientations on thin film lubrication of a magnetic recording system

In this paper, the relations expressing the effects of roughness orientations and molecular mean free path on the roughness-induced flow factors are derived. Such consideration of the effects of roughness orientation on bearing performance is necessary when rotary actuators are used in magnetic recording systems. Using the perturbation approach and the coordinate transformation, the flow factors are derived and expressed as functions of the roughness orientations, the Peklenik numbers, the standard deviations of roughness heights of each surfaces, the inverse Knudsen number and the film thickness ratio of the lubrication film, where h/ sigma is the ratio of average film thickness to standard deviation of the composite roughness. Two orientation coefficients are proposed to reveal the combined effects of Peklenik number and orientation angle and the change of flow factors is analysed as the orientation coefficients vary. Finally, the static performance of a magnetic recording head flying above a rotating disc under the ultra-thin-spacing condition is analysed with roughness and rarefaction effects taken into account. The effects of surface characteristics of the moving surface on load capacity are more significant than those of the stationary surface.
Elementary graphics of cyclicity 1 and 2

In this paper we elaborate the techniques to prove for several elementary graphics that their cyclicity is one or two. We first prove two main results for Cinfinity vector fields in general. The first one states that a graphic through an arbitrary number of attracting hyperbolic saddles (hyperbolicity ratio r>1) and attracting semi-hyperbolic points (one negative eigenvalue) has cyclicity 1. A second result says that for a graphic with one hyperbolic and one semi-hyperbolic singularity of opposite character the cyclicity is two. We then specialize to graphics with fixed connections and show that 33 graphics appearing among quadratic systems and listed in a previous paper have a cyclicity at most two (five cases are done only under generic conditions).
Numerical Modeling of the Solar Tachocline. I. Freely Evolving Stratified Turbulence in a Thin Rotating Spherical Shell

The solar tachocline is a differentially rotating shear layer that appears to be largely located in a stably stratified region of the solar interior, immediately below the convective envelope. Turbulence could be generated in this layer by overshooting convection and by shear instabilities. In order to study the nature of such turbulence, we introduce a three-dimensional nonlinear model of stably stratified fluid motions in a thin rotating spherical shell. Numerical solutions of the freely evolving system are presented for a variety of random initial conditions and parameter values. The velocity field is decomposed into a Rossby-wave (r-mode) component and a gravity-wave (g-mode) component, and their evolution and interaction is investigated. The two components are closely coupled when the rotation is rapid, with oscillatory exchanges of energy and wave modes that propagate toward the equator. Upscale kinetic energy transfer is produced by nonlinear interactions among r-modes and also among g-modes when the stratification is strong.
Distribution theory of group sequential t,χ2and F-tests for general linear models

We derive the joint distribution of the sequence of estimates of the parameter vector θ in a normal general linear model when data accumulate over a series of analyses. This seclllerlce of estimates has a remarkably simple covariance structure, even when observations are correlated, allowing standard group sequential tests to be applied in very general settings. If observations variaices and covariances depend on an unknown scale factor σ2, the joint distribution of the sequence of estimates of θ σ2 has a simple form. again even in the case of correlated observations. From these results, we establish a general treatment of group sequential t,χ2and F-tests.
Measurement of the (1s) Lamb shift of hydrogen-like krypton

The absolute energy of the Lyman- alpha 1 line of hydrogen-like krypton has been measured with an accuracy of 36 p.p.m. The ions were produced at GANIL (Caen) and the X-rays emitted in flight detected with a flat crystal spectrometer. The (1s) Lamb shift of hydrogen-like krypton has been found to be 11.95+or-0.5 eV in good agreement with theory.
Some Bayesian and Non-Bayesian Procedures for the Analysis of Comparative Experiments and for Small-Area Estimation: Computational Aspects, Frequentist Properties, and Relationships

Abstract The estimation of a treatment contrast from experimental data and the estimation of a small-area mean are special cases of the prediction of the realization of a linear combination of fixed and random effects in a possibly unbalanced two-part mixed linear model. In this article a Bayesian approach to point and interval prediction is presented and its computational requirements are examined. Differences between the Bayesian approach and the traditional (classical) approach are discussed in general terms and, in addition, in terms of two examples taken from the literature: (1) the comparison of drug formulations in a bioavailability trial (Westlake) and (2) the estimation of corn-crop areas using satellite data (Battese, Harter, and Fuller). Some deficiencies in the classical approach are pointed out, and the Bayesian approach is considered from a frequentist perspective. It is shown, via a Monte Carlo study, that, for certain (noninformative) choices of the prior distribution, the frequentist prop.