Miracle-dz/UniFAR-FTUs huggingface dataset:
A Functional Monte Carlo Method for k-Eigenvalue Problems

Abstract In Monte Carlo simulations of k-eigenvalue problems for optically thick fissile systems with a high dominance ratio, the eigenfunction is often poorly estimated because of the undersampling of the fission source. Although undersampling can be addressed by sufficiently increasing the number of particles per cycle, this can be impractical in difficult problems. Here, we present a new functional Monte Carlo (FMC) method that minimizes this difficulty for many problems and yields a more accurate estimate of the k-eigenvalue. In the FMC method, standard Monte Carlo techniques do not directly estimate the eigenfunction; instead, they directly estimate certain nonlinear functionals that depend only weakly on the eigenfunction. The functionals are then used to more accurately estimate the k-eigenfunction and the eigenvalue. Like standard Monte Carlo methods, the FMC method has only statistical errors that limit to zero as the number of particles per cycle and the number of cycles become large. We provide numerical results that illustrate the advantages and limitations of the new method.
Duality theorems for convex programming without constraint qualification

Abstract Invoking a recent characterization of Optimality for a convex programming problem with finite dimensional range without any constraint qualification given by Borwein and Wolkowicz, we establish duality theorems. These duality theorems subsume numerous earlier duality results with constraint qualifications. We apply our duality theorems in the case of the objective function being the sum of a positively homogeneous, lower-semi-continuous, convex function and a subdifferentiable convex function. We also study specific problems of the above type in this setting.
Low Threshold Current Density Operation of a GaInAsP/Si Hybrid Laser Prepared by Low-Temperature N2 Plasma Activated Bonding

The integration of III–V active devices on a Si platform utilizing direct bonding is an attractive way to realize large-scale photonic integrated circuits. Because plasma activated bonding (PAB) is expected to have a higher bonding strength at a lower heating temperature as compared to conventional bonding methods, PAB is attractive for the reduction of non-radiative recombination centers in the III–V active region caused by thermal expansion during the bonding process. A GaInAsP/Si hybrid laser was fabricated with low-temperature (150 °C) N2 PAB, and a low threshold current density of 850 A/cm2 (170 A/cm2 per quantum well) was obtained.
Spatial and temporal fluctuations in sunspots derived from MDI data

The penumbra radiates an energy flux that is 0.75–0.8 times the photospheric value. One mechanism proposed to bring this flux to the surface is interchange convection according to which hot flux tubes rise to the surface, lie horizontally there while they cool and finally sink down again. We search for possible signatures of such a process using time series of magnetograms and continuum images recorded by the Michelson Doppler Imager (MDI) in its high resolution mode (0.6´´pixels). The data reveal that at the spatial scales accessible to MDI, magnetic structures are on average smaller in the azimuthal direction than brightness features. The small-scale magnetic pattern resolvable by MDI lives for well over two hours, i.e. longer than the brightness pattern. As shown in a parallel paper (Schlichenmaier & Solanki [CITE]) this result, taken together with theoretical predictions, suggests that interchange convection is unable to account for the observed penumbral radiative flux. The need for higher resolution data obtained under stable conditions is pointed out.
Four Probable T Tauri Stars in MBM 12

Survey observations were carried out in the MBM 12 (sometimes referred to as Lynds 1457) dark cloud in search of Hα emission stars by using a slitless grism spectrograph on the 2.6-m reflector of Byurakan Astrophysical Observatory, Armenia. Four new Hα stars were detected by the survey and identified as candidate T Tauri stars by follow-up low-dispersion spectroscopy and/or near-infrared photometry.
Neutron Star Crustal Plate Tectonics. III. Cracking, Glitches, and Gamma-Ray Bursts

When the growing vortex pinning stresses in a cool, spinning-down superfluid neutron star strain the crust beyond its elastic yield strength, large-scale crust cracking events may occur. These would result in pulsar timing glitches with magnitude and recurrence rates near those observed. In old or dead radio pulsars these sudden releases of stored elastic energy should give bursts of X-ray and gamma-rays whose number, energy, and rise time suggest those of the so far unidentified gamma-ray burst sources
A theory crack healing in polymers

A theory of crack healing in polymers is presented in terms of the stages of crack healing, namely, (a) surface rearrangement, (b) surface approach, (c) wetting, (d) diffusion, and (e) randomization. The recovery ratio R of mechanical properties with time was determined as a convolution product, R = Rh (t)*φ(t), where Rh (t) is an intrinsic healing function, and φ(t) is a wetting distribution function for the crack interface or plane in the material. The reptation model of a chain in a tube was used to describe self‐diffusion of interpenetrating random coil chains which formed a basis for Rh (t). Applications of the theory are described, including crack healing in amorphous polymers and melt processing of polymer resins by injection or compression molding. Relations are developed for fracture stress σ, strain e, and energy E as a function of time t, temperature T, pressure P, and molecular weight M. Results include (i) during healing or processing at t
Experimental Study of Atmospheric Neutrino Flux in the NUSEX Experiment

The fully contained events detected in the NUSEX nucleon stability experiment have been analysed to search for possible anomalies in the fluxes of atmospheric neutrinos. The measured flux of muon neutrinos is in very good agreement with predictions and no anomaly has been found in the ratio between the rate of electron and muon neutrino events.
The 87GB catalog of radio sources covering delta between O and + 75 deg at 4. 85 GHz

The 91-m telescope in Green Bank was used during October 1987 to map 6.0 sr of sky in the delta between 0 and + 75 deg declination band at 4.85 GHz. The 87GB catalog of 54,579 discrete sources with angular sizes of less than about 10.5 arcmin and stronger than about 25 mJy is derived from these maps. The catalog positions and flux densities have been corrected for known map biases. Their estimated rms uncertainties were verified by comparison with more accurate positions and flux densities available for some sources. The 4.85 GHz normalized source counts between 25 mJy and 10 Jy were obtained and agree well with evolutionary models based on independent data. The catalog is available in both printed and machine-readable versions. 11 refs.
Antiplane electro‐mechanical field of a bimaterial piezoelectric wedge under a pair of concentrated forces and surface charges

Abstract This paper presents the general solutions of the antiplane electro‐mechanical field for a bimaterial piezoelectric wedge subjected to a pair of concentrated forces and surface charges. Identical wedge angles are assumed here. Using the Mellin transform method, the singularity orders and the generalized stress, strain, electric displacement and electric field intensity factors are derived analytically. The discussion of a semi‐infinite crack at the interface of two bonded piezoelectric half‐planes is also included. Some degenerated cases are investigated to check the accuracy of the obtained solutions.
Parameter Design for Signal-Response Systems: A Different Look at Taguchi's Dynamic Parameter Design

A recent trend in the industrial applications of robust pa- rameter design is to consider complex systems which are called "sys- tems with dynamic characteristics" in Taguchi's terminology or signal- response systems in this paper. This potentially important tool in quality engineering lacks a solid basis on which to build a rigorous body of the- ory and methodology. The purpose of this paper is to provide such a basis. We classify signal-response systems into two broad types: mea- surement systems and multiple target systems. Three issues are then of fundamental importance. First, a proper performance measure needs to be chosen for system optimization, and this choice depends on the type of system. Taguchi's dynamic signal-to-noise ratio is shown to be appropri- ate for certain measurement systems but not for multiple target systems. Second, there are two strategies for modeling and analyzing data: perfor- mance measure modeling and response function modeling. Finally, the proper design of such experiments should take into account the model- ing and analysis strategy. The proposed methodology is illustrated with a real experiment on injection molding.
Gender inclusive physics education—a distance case

In earlier studies, it has been demonstrated that cooperative work has a positive influence on physics distance learning at university entrance level. In this paper, it is shown clearly that this teaching method in physics is advantageous for both genders. In fact, the collaboration seems to help male students more than female students to manage the course and to complete it. No difference was seen between the genders either in performance, measured in throughput (productivity) for the course, or in intrinsic motivation. Without cooperative work, the productivity for male students is far lower than for female students.
Families of invariants of the motion for the Lotka–Volterra equations: The linear polynomials family

The modified Carleman embedding method already introduced by the authors to find first integrals (invariants of the motion) of polynomial form to the Lotka–Volterra system is described in detail, and its efficiency to treat the N‐dimensional system proved. Using this method, an extensive investigation is performed for polynomials of the first degree, which allow a classification of the integrals in three families. For some systems possessing one invariant it is possible to find a second invariant using rescaling methods. They represent very restrictive solutions, implying that there exists a great number of conditions among the equation’s coefficients to satisfy. A proof is given that the Volterra invariants can be deduced as a limit. Finally, the interesting properties of the solutions of these systems are studied in detail.
Time Series Models in Non‐Normal Situations: Symmetric Innovations

We consider AR(q) models in time series with non‐normal innovations represented by a member of a wide family of symmetric distributions (Student's t). Since the ML (maximum likelihood) estimators are intractable, we derive the MML (modified maximum likelihood) estimators of the parameters and show that they are remarkably efficient. We use these estimators for hypothesis testing, and show that the resulting tests are robust and powerful.
Effect of Ru substitution for Re on the thermoelectric properties of AlPdRe icosahedral quasicrystals

The thermoelectric properties of the quaternary AlPdReRu icosahedral quasicrystals (i-AlPdReRu) obtained by replacing Re with Ru in AlPdRe icosahedral quasicrystals have been studied. In the middle of the substitution of Ru for Re, the electrical conductivity increases and the peak of Seebeck coefficient shifts to a higher temperature side. By Ru substitution for the AlPdRe quasicrystal, the dimensionless figure of merit (ZT) increases 1.5 times from 0.1 to 0.15. According to the result of two-band analysis, the effective mass has peaks at both the compositions of i-AlPdRe and i-AlPdReRu which reveal the peak ZT values. We ascribe the behavior of effective mass to the change in the bond strength of intra- and inter-Mackay icosahedral clusters.
Solution of the One‐Dimensional N‐Body Problems with Quadratic and/or Inversely Quadratic Pair Potentials

The quantum‐mechanical problems of N 1‐dimensional equal particles of mass m interacting pairwise via quadratic (``harmonical'') and/or inversely quadratic (``centrifugal'') potentials is solved. In the first case, characterized by the pair potential ¼mω2(xi − xj)2 + g(xi − xj)−2, g > −ℏ2/(4m), the complete energy spectrum (in the center‐of‐mass frame) is given by the formula E=ℏω(12N)12[12(N−1)+12N(N−1)(a+12)+ ∑ l=2Nlnl], with a = ½(1 + 4mgℏ−2)½. The N − 1 quantum numbers nl are nonnegative integers; each set {nl; l = 2, 3, ⋯, N} characterizes uniquely one eigenstate. This energy spectrum can also be written in the form Es = ℏω(½N)½ [½(N − 1) + ½N(N − 1)(a + ½) + s], s = 0, 2, 3, 4, ⋯, the multiplicity of the sth level being then given by the number of different sets of N − 1 nonnegative integers nl that are consistent with the condition s=∑l=2Nlnl. These equations are valid independently of the statistics that the particles satisfy, if g ≠ 0; for g = 0, the equations remain valid with a = ½ for Fermi st.
Some Aspects of the Flow of Stratified Fluids

The investigations of Parts I and II are extended to include experiments and theoretical considerations relating to the behavior of fluid systems with continuous gradients of density. The general equation of steady-state motion derived in Part I is integrated to yield the flow of a stratified fluid over an obstacle of finite dimensions. The results indicate a more or less complicated laminar wave motion for obstacles of maximum height below a certain value. Larger barriers cause an overdevelopment of the waves to a point where closed circulations and negative horizontal velocities appear. It is shown that this is accompanied by locally unstable distributions of density and eventual turbulence. If the height of the barrier is further increased, the velocity increases indefinitely in some parts of the field, becoming infinite for an obstacle of a certain size. No steady-state solution exists for larger barriers. The two critical values of the obstacle height depend primarily on the Froude number: If this number exceeds 1/π the solution exists and is stable for all obstacles; for small Froude numbers the barrier must be small if the solution is to exist or be stable. If the obstacle is small enough to permit laminar or moderately turbulent motion, the accompanying experiments verify all important features of the theory with remarkable fidelity. Larger obstacles cause considerable turbulence and blocking effects which propagate upstream, causing alternate maxima (jets) and minima of horizontal velocity in the vertical. DOI: 10.1111/j.2153-3490.1955. tb01171.x
Atomic Data for the Re II UV 1 Multiplet and the Rhenium Abundance in the HgMn-type Star χ Lupi

We report new laboratory spectroscopic analyses that have been conducted to acquire wavelength and oscillator strength data for lines of the Re II UV 1 multiplet. Wavelengths were determined to a sub-milliangstrom accuracy for the hyperfine and isotopic structure components from laboratory spectra obtained with the Lund VUV Fourier Transform Spectrometer. An absolute atomic transition probability is reported for Re II 2275.253 Å, obtained from its upper level lifetime and an experimentally determined branching fraction. The radiative lifetime of the z 7Po2 level was found to be 4.47 ± 0.22 ns by the method of laser-induced fluorescence. With the new atomic data, synthetic spectra were generated to fit a Hubble Space Telescope Goddard High Resolution Spectrograph echelle mode spectrum of the chemically peculiar HgMn-type star χ Lupi. The weakness of the λ2275.253 Å feature only allowed for the determination of an upper limit to the rhenium abundance, which was found to be consistent with the meteoritic value. Thus, in χ Lupi, rhenium appears to be several orders of magnitude less abundant than the apparent surficial abundances of the slightly heavier elements Pt, Au, Hg, and Tl.
Detection of Multiple Component Signals in Noise

The detectability of a complex signal, one generated by adding two sinusoids, and partially masked by white noise, is determined. Several frequencies and three durations are used for the signal. The experimental determinations are compared with three mathematical models. These models are all interpretable as an extension of the critical band concept. The data are best explained by a model in which it is assumed that two or more critical bands may be linearly combined. This implies that the auditory mechanism may change the appropriate parameters of the analysis process in order to match the signal to be detected.
Evaluation of 1/ν neoclassical transport in stellarators

Using an analytic solution of the kinetic equation in the 1/ν regime, a new formula for the neoclassical transport coefficients is obtained which takes into account all classes of trapped particles. This formula holds in any coordinate system and no simplifying assumptions about the magnetic field are needed. Therefore it is also applicable to complex magnetic fields given in real space coordinates. The method and the results can be used to optimize magnetic field configurations with respect to the 1/ν regime. The method is bench-marked against Monte Carlo calculation both for the l=3 classical stellarator model and also for the original Helias configuration [J. Nuhrenberg and R. Zille, Phys. Lett. A 114, 129 (1986)] with a more complex magnetic field structure. Some features of transport for Helias are clarified by analyzing the bounce-averaged drift velocity.
On certain two-dimensional conservative mechanical systems with a cubic second integral

In a previous paper (Yehia H M 1986 J. Mec. Theor. Appl. 5 55–71) we have introduced a method for constructing integrable conservative two-dimensional mechanical systems whose second integral of motion is polynomial in the velocities. This method has proved successful in constructing a multitude of irreversible systems (involving gyroscopic forces) with a second quadratic integral (Yehia H M 1992 J. Phys. A: Math. Gen. 25 197–221). The objective of this paper is to apply the same method for the systematic construction of mechanical systems with a cubic integral. As in our previous works, the configuration space is not assumed to be a Euclidean plane. This widens the range of applicability of the results to diverse mechanical systems to include such problems as rigid body dynamics. Several new reversible and irreversible integrable systems are obtained. Some of these systems generalize previously known ones by introducing additional parameters which may change either or both of the configuration manifold and the potential of the forces acting on the system. Other systems are completely new. An application is given to problems of rigid body dynamics. The famous classical integrable case due to Goriachev and Chaplygin and all its subsequent generalizations by several authors are further generalized to include certain variable gyroscopic forces that preserve a cubic integral. On the other hand, the above case and another less famous case of rigid body dynamics due to Goriachev and the Hall–Toda case of particle mechanics are all obtained as special cases, corresponding to different choices of certain parameters, from one more general system unifying them all.
Energy‐flux relationship in the FUV Jovian aurora deduced from HST‐STIS spectral observations

[1] Far ultraviolet spectral observations of the Jovian aurora have been made since 1997 with the Space Telescope Imaging Spectrograph (STIS) on board the Hubble Space Telescope at low spectral resolution. The combination of the spectral resolution with the intensity variation along the STIS slit provides information on the latitudinal variation of the precipitating auroral electron energy flux and the mean electron energy, from which the electron current density at the top of the atmosphere can also be deduced. It is found that the mean electron energies associated with the main oval lie in the range 30–200 keV and show a tendency to increase with the precipitating energy flux. The current densities lie in the range ∼0.04–0.4 μA m−2, consistent with previous estimates, and are also positively correlated with the energy flux. The observed relationship between the auroral time-integrated energy fluxes and the electron energies in the main oval is compatible with that expected from Knight's theory of field-aligned currents. The best agreement between the observed data and the Knight curves is obtained for an electron temperature of Te = 2.5 keV and a source density N = 0.003 cm−3, that is within the range of values observed in the equatorial plane during the Voyager flybys. No systematic dependence of the electron energy with magnetic local time is found, but the morning sector around 0800 MLT shows greater variability than other regions of the oval. Analysis of time-tagged data shows that the main oval energy flux usually varies steadily over the several minute intervals of observation and that the mean electron energy usually undergoes correlated variations such that the current density remains relatively constant. It is shown that these overall properties are also consistent with Knight's theory of auroral electron acceleration associated with field-aligned current flow, from which it is inferred that the temporal variations observed are often due to slow changes in the magnetospheric “source” electron parameters in the presence of near-steady magnetosphere-ionosphere coupling currents. By contrast, time-integrated emissions in the polar region are found to be associated with similar mean electron energies to the main oval but with typically smaller energy fluxes and current densities. Pressure balance arguments are advanced, which indicate that the brighter of these emissions must be associated with an auroral acceleration mechanism perhaps similar to that operative in the main oval, while it remains possible that the weaker emissions could result from precipitation from a quasi-isotropic hot magnetospheric electron source.
A Table of Complex Cubic Fields

A table of real cubic fields with discriminant less than 20,000 is given by Godwin and Samet [6]. This paper describes the construction of a complementary table of the 3169 non-conjugate complex cubic fields with discriminants greater than -20,000, which extends the existing table for discriminants greater than -1000 given by Delone and Faddeev [3]. The basis of this calculation is the following theorem, similar to one used by Godwin [5].