Miracle-dz/UniFAR-FTUs huggingface dataset:
A Measurement of the Sunyaev-Zel'dovich Effect in the Coma Cluster of Galaxies

We report the detection of the Sunyaev-Zel'dovich effect in the Coma cluster of galaxies with the 5.5 m telescope at the Owens Valley Radio Observatory. The measured decrement of the temperature of the cosmic microwave background is ΔT0,obs = -270 ± 29 μK. After correcting for the effect of discrete radio sources and applying current models for the X-ray atmosphere of the cluster, we calculate the peak of the effect to be ΔT0(0) = -505 ± 92 μK. Using the same X-ray models, and assuming spherical symmetry for the gas atmosphere, we derive a Hubble constant of H0 = 71+ 30−25 km s-1 Mpc-1. This is the first detection of the Sunyaev-Zel'dovich effect in a nearby cluster of galaxies.
Teaching the Reasoning of Statistical Inference: A "Top Ten" List

Allan Rossman (rossman@dickinson.edu) has taught at Dickinson College since receiving his Ph.D. in statistics from Carnegie Mellon in 1989. He has developed interactive curricular materials through which students explore principles of introductory statistics. He directs the MAA'sSTATS (Statistical Thinking with Active Teaching Strategies) project, which conducted workshops for mathematicians who teach statistics. With mixed success he applies his statistical training to managing his fantasy baseball team, the Domestic Shorthairs.
Dispersion equation and eigenvalues for the Zakharov-Shabat system using spectral parameter power series

A general solution of the Zakharov-Shabat system with a real valued potential is obtained in terms of spectral parameter power series. It is used for deriving a dispersion (characteristic) equation for the Zakharov-Shabat eigenvalue problem with a compactly supported potential. Due to its convenient form the dispersion equation lends itself to numerical solution providing a simple and accurate numerical method for solving the Zakharov-Shabat eigenvalue problem.
Free Planar Motion of Flexible Beams in MBS – A Comparison of Models

Abstract Two approaches for the description of free planar motion of elastic beam structures are studied: a method using redundant coordinate sets to maintain a moving frame of reference (MFR) discretization in a finite element formulation and the absolute nodal coordinate formulation (ANCF). Both are treated within the modern framework for multi-body systems including bi- and unilateral constraints as well as non-smooth dynamics. Numerical efficiency and accuracy of the models are investigated using two examples: A slider-crank mechanism with a flexible beam is used to study computational cost and the convergence for finer spatial discretizations. Non-smooth dynamics is studied for an elastic rocking rod built of an elastic beam bouncing on two fixed point obstacles.
Stable and bias-corrected estimation for nonparametric regression models

It is well known that in nonparametric regression setting, the common kernel estimators are sensitive to bandwidth and can not achieve a satisfactory convergence rate, especially for multivariate cases. To improve nonparametric estimation in the sense of both selection of bandwidth and convergence rate, this paper proposes a two-stage (or three-stage) regression estimation by combining nonparametric regression with parametric regression. The optimal design conditions, including the optimal bandwidth, are obtained. The newly proposed estimator has a simple structure and can achieve a smaller mean square error without use of the higher order kernel. Even if the prior selections of nonparametric estimation are not optimal (i.e. the smooth parameter is not optimally chosen), the new two-stage estimator still has a satisfactory convergence rate. This means that the newly proposed estimator is robust to the selection of bandwidth and then is a practical method. This new method is also suitable for general nonparametric regression models regardless of the dimension of explanatory variable and the structure assumption on regression function.
The effect of Brownian diffusion on shear-induced coagulation of colloidal dispersions

The effect of a small amount of Brownian diffusion on shear-induced coagulation of spherical particles has been calculated. This has been accomplished by considering the binary collision process between a test sphere and identical spheres interacting with the test sphere through induced-dipole attraction, electrostatic repulsion and hydrodynamically induced forces. The effect of diffusion is found by means of an expansion in inverse Péclet number. Specific calculations were performed for uniaxial extension and for laminar shear flow. It is found that Brownian diffusion, the effect of which is nonlinearly coupled with flow type and strength, can act to increase or decrease the coagulation rate.
Resistance to complexity interacting with visual shape—German and Korean orthography

The aim of this article is to develop an optimality-theoretic account of orthographic phenomena concerning the correlation between phonetic and non-phonetic visual elements and their underlying forces. We analyse the interaction between visibility and simplicity and its influence on orthographic forms. This interaction is represented firstly by visual markers for vowel length and the restriction on the doubling of a vowel in German orthography, then by historical changes of letter shape and grapheme insertion in Korean orthography. Furthermore, it is shown that German and Korean orthographic syllables can be classified into two different types, resulting again from the interaction between visibility and simplicity. We claim that simplicity influences the possibilities of letter combinations and visual shape, and vice versa, and that orthographic syllables can be classified as either invisible or visible. This article is based on Optimality Theory (Prince, A. and Smolensky, P. (1993), Optimality Theory: Constraint interaction in generative grammar. Cornwall: Blackwell (2004)), which allows for the description of languages by means of constraints, and of the variation between languages by means of different rankings of these constraints in German and Korean, respectively.
Shaping of femtosecond pulses using phase-only filters designed by simulated annealing

We describe generation of shaped femtosecond waveforms by using frequency-domain phase-only filters designed by numerical optimization techniques. The task of filter design for pulse shaping in the time domain is directly analogous to the design of phase-only filters for beam shaping and array generation in the spatial domain. We experimentally tested phase filters that were designed to produce ultrafast square and triangle pulses and femtosecond pulse sequences. Our results demonstrate the ability to generate high-quality terahertz-repetition-rate sequences of femtosecond pulses by means of low-loss phase-only filtering. On the other hand, experiments that tested generation of individual shaped pulses, such as square pulses, were less successful than previous experiments that used simultaneous phase and amplitude filtering. Our results indicate the importance of building increased robustness against variations in the input pulse shape into the phase-only filter design.
On the multifractal properties of the energy dissipation derived from turbulence data

Various difficulties can be expected in trying to extract from experimental data the distribution of singularities, the f(α) function, of the energy dissipation. One reason is that the multifractal model of turbulence implies a dependence of the viscous cutoff on the singularity exponent. It is an open question if current hot-wire probes can resolve the scales implied by exponents a significantly less than 1. Two exactly soluble models are used to show how spurious scaling can occur, due to finite Reynolds number effects. In the Gaussian model the true velocity signal is replaced by independent Gaussian random variables. The dissipation, defined as the square of the difference of successive variables, has trivial scaling in so far as all the moments of spatial averages of the dissipation behave asymptotically as a uniform dissipation. Still, contamination by subdominant terms requires that scaling exponents for high-order moments be identified over an increasingly large range of scales. If the available range is limited by the Reynolds number, scaling exponents for high orders will be systematically underestimated and spurious intermittency will be inferred. Burgers’ model is used to highlight further problems. At finite Reynolds numbers, regions with no small-scale activity (away from shocks) have a residual dissipation which contributes a spurious point (α = 1,f(α) = 1). In addition, when the f(α) function is obtained by Legendre transform techniques, convex hull effects generate an entire spurious segment. Finally, Burgers’ model also indicates that the relation between exponents of structure functions and exponents of local dissipation moments, which goes back to Kolmogorov's (1962) work, leads to an inconsistency for structure functions of low positive order.
Parallel finite element calculation of flow in a three-dimensional lid-driven cavity using the CM-5 and T3D

Steady flows in a three-dimensional lid-driven cavity at moderate Reynolds number are studied using various methods of parallel programming on the Cray T3D and Thinking Machines CM-5. These three-dimensional flows are compared with flows computed in a two-dimensional cavity. Solutions at Reynolds number up to 500 agree well with the experimental data of Aidun et al. (Phys. Fluids A, 3, 2081-2091 (1991)) for the location of separation of the secondary eddy at the downstream wall. Convergence of the three-dimensional problem using GMRES with diagonal preconditioning could not be obtained at Reynolds number greater than about 500. We speculate that the source of the difficulty is the loss of stability via pitchfork and Hopf bifurcations identified by Aidun et al. The relative performance of various methods of message passing on the Cray T3D is compared with the data-parallel mode of programming on the CM-5.
AlGaAs superlattice microcoolers

AlGaAs-based superlattice microcoolers are demonstrated. Maximum cooling temperatures of 0.8 °C and 2 °C were obtained at 25 °C and 100 °C, respectively, from 60 μm×60 μm devices with 100 period Al0.10Ga0. 90As/Al0.20Ga0.80As n-type superlattice thermal barriers. These devices may be useful for in situ cooling of GaAs-based microelectronic and optoelectronic devices.
Overturning in a filling box

Overturning in a cylindrical filling box driven by a turbulent plume is examined theoretically and experimentally. We establish the initial penetration depth (h) of the buoyant flow that intrudes vertically up the sidewall as a function of the box radius (R) and height (H). Dimensional arguments reduce the problem to finding η = h/H as a function of the aspect ratio Φ = R/H. The flow is modelled in two parts, the radial outflow from the plume along the base of the box and the flow up the sidewall. The outflow is modelled as a forced radial gravity current with constant buoyancy flux while the sidewall flow is modelled as a line fountain. Two regimes were found: first, when the plume outflow is adjusting toward a pure gravity current on impact with the vertical wall and the rise height is given by η ∼ Φ−1/3; secondly, when the outflow is fully developed on, or before, impact and the rise height is given by η ∼ Const. Experimental results show good agreement with these scalings and allow the constants of proportionality to be established.
Small-Sample Properties of GMM-Based Wald Tests

This article assesses the small-sample properties of generalized-method-of-moments-based Wald statistics by using (a) a vector white-noise process and (b) an equilibrium business-cycle model as the data-generating mechanisms. In many cases, the small-sample size of the Wald tests exceeds its asymptotic size and increases sharply with the number of hypotheses being jointly tested. We argue that this is mostly due to difficulty in estimating the spectral-density matrix of the residuals. Estimators of this matrix that impose restrictions implied by the model or the null hypothesis substantially improve the properties of the Wald statistics.
Correlation of the peak pressure generated by an underwater spark discharge with energy absorption in a spark channel

In this paper, we have explained the correlation between the amplitude of the underwater shock pressure generated by a spark discharge in water and the energy absorption in a spark channel. With the well-known theory of shock wave formation by an accelerating piston, the peak pressure is considered to be generated by the energy absorption in the spark channel until the expansion speed of the spark channel reaches its maximum value. To obtain the maximum channel speed, we solve the power balance equation with experimentally measured voltage and current waveforms as a transient heating source of the spark channel. It is found that the experimentally measured peak pressure is well correlated with the energy absorption until the maximum channel expansion speed, irrespective of the operating parameters such as the capacitance and the voltage. It is also found that the energy absorption in the spark channel is significantly influenced by the spark channel resistance, indicating that an appropriate resistance model for the spark channel is necessary for an improved analysis of an underwater spark discharge system. The physics-based estimation of the peak shock pressure presented in this paper is expected to be useful for optimizing underwater spark discharge systems utilized in various application fields.
Combined Effects of Perturbations, Radiation, and Oblateness on the Stability of Equilibrium Points in the Restricted Three-Body Problem

This paper investigates the stability of equilibrium points under the influence of small perturbations in the Coriolis and the centrifugal forces, together with the effects of oblateness and radiation pressures of the primaries. It is found that collinear points remain unstable. It is also seen that triangular points are stable for 0 ≤ μ < μc and unstable for μc ≤ μ ≤ , where μ is the critical mass parameter and depends on the above parameters. It is further observed that the Coriolis force has a stabilizing tendency, while the centrifugal force, radiation, and oblateness of the primaries have destabilizing effects; the presence of any one or more of the latter makes weak the stabilizing ability of the former. Therefore, the overall effect is that the range of stability of the triangular points decreases.
Non-thermal emission in Wolf-Rayet stars: are massive companions required?

We examine the radio spectral indices of 23 Wolf–Rayet (WR) stars to identify the nature of their radio emission. We identify nine systems as non-thermal emitters. In seven of these systems the non-thermal emission dominates the radio spectrum, while in the remaining two it is of comparable strength to the thermal, stellar wind emission, giving ‘composite’ spectra. Among these nine systems, seven have known spectroscopic or visual binary companions. The companions are all massive O or early B-type stars, strongly supporting a connection between the appearance of non-thermal emission in WR stars and the presence of a massive companion. In three of these binaries, the origin of non-thermal emission in a wind-collision region between the stars has been well established in earlier work. The binary systems that exhibit only thermal emission are all short-period systems where a wind-collision zone is deep within the opaque region of the stellar wind of the WR star. To detect non-thermal emission in these systems requires optically thin lines of sight to the wind-collision region.
Determining critical weed competition period in maize (Zea mays L.) sown under different tillage intensities.

A field experiment was conducted at the Agronomic Research Area, Department of Agronomy, University of Agriculture, Faisalabad to determine the critical weed competition period in maize (Zea mays L.) sown under different tillage intensities. The field trial was laid out with split plot design having three replicates with a net plot size of 4.5 m x 6 m. The experiment comprised of three tillage practices namely deep cultivation with disc plough + 3 cultivations with cultivator, rotavator + 3 cultivations with cultivator, and only 3 cultivations with cultivator; and five weed competition periods of 20, 30, 40 days after crop emergence along with weed free and weedy check. The linear increase in the density of weeds (m -2 ) with the competition periods would be due to more time period available for weed seed germination which ultimately resulted in the reduction of total grain yield. Plant population at harvest, number of grains cob -1 , number of grain rows cob -1 , total number of grains cob -1 , 1000-grain weight (g), grain yield, dried stalk yield and biological yield were maximum in disc plough + 3 cultivations with cultivator.
Correlation and modeling between color variation and quality of the surface between accelerated and natural tropical weathering in Acacia mangium, Cedrela odorata and Tectona grandis wood with two coating

To prevent the photodegradation process, a wide range of coatings have been developed. This study evaluated wood color change (ΔE*) and the surface quality index (SQI) generated by ASTM D-660 standards in wood protected with polyurethane and varnish finishes of three tropical species (Acacia mangium, Cedrela odorata and Tectona grandis) in two weathering conditions (natural and accelerated condition). In addition, a model was developed to predict ΔE* and SQI in natural weathering based on ΔE* and SQI from accelerated weathering. The results showed that the application of these finishes generated variations in the color parameters of wood before being exposed to the elements. Additionally, it was found that finishes generated increases in ΔE*, especially the varnish type finish, and decreasing of SQI. Finally, models were found to predict color changes or surface quality in natural weathering based on color changes or surface quality in accelerated weathering. The model algorithm was expressed by ΔE* or SQI measured (X) and time exposure (t) in accelerated weathering by equation . With these models, it is possible to predict the equivalence of exposure times in natural weathering in tropical conditions for different kinds of finishes in three tropical species. © 2013 Wiley Periodicals, Inc. Col Res Appl, 39, 519–529, 2014
Entry effects in the open thermosyphon

In this paper flow-visualization techniques are used to study the flow instability which occurs at the orifice in the free convection open thermosyphon. The influence of the shape of the orifice on the measured heat transfer of the system is also studied under both laminar and turbulent conditions. The dominant mode of penetration of the hot stream by the cold fluid entering at the base of the reservoir is found to instigate a mixing region at the orifice. In turbulent flow this spreads into and eventually fills the tube as the Rayleigh number is increased. In such circumstances a sharp-edged orifice appears to give better overall heat transfer than a rounded orifice.
Electronic structure, phase transition, and elastic properties of ScC under high pressure

The structural properties and the phase transition for scandium carbide (ScC) have been studied in NaCl (B1), CsCl (B2), ZB (B3), WZ (B4), NiAs (B81), WC (Bh), and Pmmn structures by using the pseudopotential plane-wave method in the framework of the density functional theory. Our theoretical results show that the most stable structure is the B1 phase, contrary to the result of Rahim et al. The phase transitions B1 → Pmmn and Pmmn → B2 are predicted at 83.7 and 109.7 GPa, respectively. At the same time, we find that the B3, B4, B81, and Bh phases are not stable over the whole pressure range considered. In particular, the elastic constants of Pmmn-ScC under high pressure are obtained successfully. The effects of pressure on the elastic properties of B1-ScC and Pmmn-ScC are also predicted. The Debye temperatures Θ and the sound velocities of these two structures are estimated from the elastic constants, and by analyzing G/B, the brittle-ductile behavior of ScC is assessed. In addition, the density of states of B1-ScC at high pressures is also discussed.
Kinematic, Static, and Dynamic Analysis of a Spatial Three-Degree-of-Freedom Tensegrity Mechanism

The use of tensegrity systems as structures has been extensively studied. However, their development for use as mechanisms is quite recent even though they present such advantages as reduced mass and a deployment capability. The object of this paper is to apply analysis methods usually reserved for conventional mechanisms to a planar one-degree-of-freedom tensegrity mechanism. This mechanism is obtained from a three-degree-of-freedom tensegrity system by adding actuation to the latter as well as by making some assumptions of symmetry. Analytical solutions are thus developed for the mechanism's direct and inverse static problems. Furthermore, the working curve, singularities, and stiffness of the mechanism are detailed. Finally, a dynamic model of the mechanism is developed and a preliminary control scheme is proposed.
The method of averaging and walks in inhomogeneous environments

CONTENTSIntroductionChapter I. General properties of walks on an inhomogeneous lattice ? 1. The invariant measure and the law of large numbers ? 2. The Lindeberg-Brown theorem and its corollaries ? 3. Time dependence. The weak central limit theorem ? 4. Ergodic theorems for fields with stationary increments. Lp(? )-estimatesChapter II. The central limit theorem for specific types of walks ? 1. Reflective symmetry ? 2. Symmetric walks ? 3. Two-fold stochastic walks ? 4. Symmetrizable walks ? 5. Walks on manifolds ? 6. Further results. Unsolved problemsReferences
The Effect of Surface Scattering On Ifsar Baseline Decorrelation

Across-track Synthetic Aperture Radar Interferometry is an emerging technique for Earth monitoring capable to generate high-resolution Digital Elevation Models. The ability to achieve such mission depends on the correlation of the signals received by the two antennas and used to generate the interferometric fringes. In this paper we formulate the baseline decorrelation due to antennas spatial diversity to include the effect of surface scattering.
Smectic-A Order at the Surface of a Nematic Liquid Crystal: Synchrotron X-Ray Diffraction

A novel geometry in which it is possible to do x-ray diffraction from a horizontal surface of fluids is applied to liquid crystals. A large-diameter drop of octyloxycyanobiphenyl (8OCB) on a glass plate treated for homeotropic alignment yields perfect alignment of the smectic-$A$ layers at the top surface over an area of several square millimeters. The surface in the bulk nematic as well as in the isotropic phase was found to consist of smectic-$A$ layers with a penetration depth equal to the longitudinal smectic-$A$ correlation length ${\ensuremath{\xi}}_{\ensuremath{\parallel}}\ensuremath{\sim}{(T\ensuremath{-}{T}_{\mathrm{NA}})}^{\ensuremath{-}{\ensuremath{\nu}}_{\ensuremath{\parallel}}}$ determined previously.