Miracle-dz/UniFAR-FTUs huggingface dataset:
SN 1994I in M51 and the nature of type Ibc supernovae

Early spectra of SN 1994I in M51 (NGC 5194) are presented along with arguments that is a member of the class of helium-poor Type Ic supernovae. The issue of H and He in the spectra of Type Ib and Ic events is reexamined with the conclusion that Type Ib eject substantially less H than even transition events like SN 1993J and that Type Ic eject substantially less He than Type Ib and their optical spectra are consistent with no H or He. Type Ic show and absorption of the Si II lambda 6355 blend that characterizes Type Ia. This feature requires only a solar abundance of Si. Some Type Ic show an absorption that is probably C II lambda 6580. IR spectra are presented of SN 1990W which show the line of He I lambda 10830. The strength of this feature and the rather slow decay of the late time light curve suggest that this event could be better classified as a Type Ib. Even if trace abundances of H are present in Type Ib and of He in Type Ic the spectral differences still imply a distinctly different evolution for the progenitors of Type Ib from Type Ic and events like SN 1993J.
Quantitative electron diffraction: From atoms to bonds

Abstract The development of new transmission electron microscopes with energy-filtering capability together with the increase in computer power over the past few years has enabled electron diffraction from inorganic crystals to become a quantitative and accurate science. With the introduction of new techniques and data analysis and with the advantage of a nanometre-sized probe, electron diffraction now rivals X-ray and neutron methods in many aspects of crystallography and solid-state physics. In this article, we have discussed two new developments which highlight the progress made in this area. First, a new method for ab-initio structure determination is explained and an example given to show its success. Second, energy-filtered diffraction patterns are used to refine the scattering potential of a crystal so that the bonding charge density can be reconstructed.
Advancements in the Field of Direct Steam Generation in Linear Solar Concentrators—A Review

Direct steam generation in parabolic trough or linear Fresnel collectors represents one interesting technological option for concentrating solar electricity production. Today's state of the art characterized by the first commercial plants in operation is a result of more than 20 years of intensive research on this topic. This article provides a review on the key results from research that includes physical effects like heat transfer and pressure drop in horizontal boiler tubes, plant layout considerations, and thermal storage options. An overview on test and demonstration facilities as well as on commercial plants is given, leading to an outlook on the next generation of direct steam generation systems.
Metric Characteristics of Nuclear Rings and Related Features in Spiral Galaxies

The metric properties of nuclear rings, pseudorings, spirals, and bars are discussed in the context of resonance theory and are used to gauge the range of sizes for such features. We find that the nuclear rings and pseudorings of strongly barred galaxies (types SB and SAB) have a wide range in linear diameter, from about 0.4 kpc in ESO 566-24 to 3.8 kpc in ESO 565-11. The mean diameter is about 1.1 kpc for a sample of 20 objects. We suggest that there are clear analogues of the nuclear rings of strongly barred spirals in both weakly barred (SAB and SAB) and nonbarred (SA) spirals. The size ratios of nuclear rings with respect to outer rings and pseudorings, as well as morphological characteristics, are best explained if outer rings and pseudorings are linked to the outer Lindblad resonance, and nuclear rings, pseudorings, and spirals are linked to the inner Lindblad resonance
RX J15542+2721: An Apparently Magnetic Cataclysmic Variable with a 2.53 Hour Orbital Period

Time‐resolved spectroscopy and photometry of the cataclysmic variable (CV) star RX J15542+2721 show it to have an orbital period of 2.53 hr, putting it in the middle of the so‐called CV period gap from 2 to 3 hr. Observations taken 2001 March show it in a low state with relatively weak emission lines and a strong contribution from a secondary star near type M4. Contemporaneous I‐band differential photometry shows ellipsoidal variations. In 2001 May the emission lines were stronger and of higher excitation, with prominent He ii λ4686, the secondary star less visible, and the ellipsoidal variations masked by flickering. By 2001 June the object had returned to a state similar to the March observations. RX J15542+2721 appears to be an AM Her–type magnetic CV. Archival plate material, although sparse, indicates that the object may spend most of its time close to minimum light. This, and a weak indication of a 2–3 hr “trough” in the histogram of AM Her star orbital periods, suggest that the mass transfer rate may be somewhat depressed among AM Her stars in this period range. The spectral type of the secondary and the orbital period are consistent with a distance of roughly 210 pc. A proper motion μ = 28 ± 4 mas yr−1 is found, corresponding to a transverse velocity ∼28 km s−1 at the nominal distance. The radial velocity variations of the M dwarf secondary are detected, and their phase is essentially as expected based on the ellipsoidal variations. The data suggest fairly typical masses for the system components, and a more detailed study might constrain the white dwarf mass rather accurately.
High-temperature superfluidity in an ultracold Fermi gas

This thesis presents experiments in which a strongly interacting gas of fermions was brought into the superfluid regime. The strong interactions are induced by a Feshbach scattering resonance that allows to tune the interfermion scattering length via an external magnetic field. When a Fermi mixture was cooled on the molecular side of such a Feshbach resonance, Bose-Einstein condensation of up to 10 molecules was observed. Subsequently, the crossover region interpolating between such a BoseEinstein condensate (BEC) of molecules and a Bardeen-Cooper-Schrieffer superfluid of long-range Cooper pairs was studied. Condensates of fermion pairs were detected in a regime where pairing is purely a many-body effect, the pairs being stabilized by the presence of the surrounding particles. Superfluidity and phase coherence in these systems was directly demonstrated throughout the crossover via the observation of long-lived, ordered vortex lattices in a rotating Fermi mixture. Finally, superfluidity in imbalanced Fermi mixtures was established, and its Clogston limit was observed for high imbalance. The gas was found to separate into a region of equal densities, surrounded by a shell at unequal densities. Thesis Supervisor: Wolfgang Ketterle Title: John D. MacAurthur Professor of Physics
Polarization and beaming of accretion disk radiation

The beaming and the polarization of finite optical depth plane-parallel accretion disks are calculated using both a Feautrier radiative transfer scheme and, independently, an iteration scheme, for the case where the opacity is dominated by nonrelativistic electron scattering. In addition to internal sources of photons, the important case of external illumination of the disk is included. The angular distribution and the polarization as a function of the angle of the emergent radiation are found to depend sensitively on the total optical depth. It is shown that the disk polarization can significantly exceed the classical limit of 11.7 percent for the case where the scattering half-thickness of the disk is small compared to unity, corresponding to subcritical conditions. The radiation pattern emerging from these scattering disks becomes more anisotropic as the optical depth decreases, alleviating some current difficulties encountered with apparent super-Eddington luminosities. 26 references.
On Ekeland's Variational Principle and a Minimax Theorem

Ekeland’s variational principle states that if a Gateaux differentiable Ž . function f has a finite lower bound although it need not attain it , then 5 Ž . 5 for every e ) 0, there exists some point x such that f x F e . This e e 5 Ž . 5 Ž paper shows that there exists some point z such that f z F er 1 q e e Ž5 5. w . w . h z , where h : 0, q` a 0, q` is a continuous nondecreasing func« q`Ž Ž Ž . tion such that H 1r 1 q h r dr s q`. As an application, a minimax 0 theorem is proved under a weak ‘‘compactness condition. ’’
Theoretical AGB and post-AGB Models for Synthetic Population Studies

Near the end of their evolution, moderate-mass stars (approximatively between 1 and 8 solar masses) go through the asymptotic giant branch (AGB) phase. The AGB and the transition to the ensuing post-AGB are very time (both computational and human) consuming to simulate. Hence, large grids of models originating from detailed calculations are rare; only few stars are generally computed. Some stellar libraries have nonetheless been constituted in the past. These are very sought-after by population synthesis modelers, as they try to reproduce observed properties of larger stellar systems by assembling together many individual models. However such AGB and post-AGB grids can rapidly become outdated because of constant input-physics ameliorations. So-called synthetic AGB models are a solution as they are computationally less time demanding: nonetheless their major drawback is that they remain approximations. In this context, new detailed models for stars of 1 to 6 solar masses, and compositions with a total heavy element content that corresponds to values between a fortieth and a double of the solar one (for two different relative scalings), have been computed. They evolve through all stellar phases from the main sequence to the white dwarf stage; here focus is on the AGB and post-AGB parts. The parameter space coverage is comparable only with the latest synthetic grids, as none of the previous detailed stellar libraries extend over such wide mass/metallicity intervals. Furthermore, the most recent physics, relevant for the AGB and post-AGB, are included. These updates, at the level of sophistication brought by this work, are present neither in synthetic nor in any detailed computations. Because they are of paramount importance, their inclusion is the major asset of this work. Specifically, three updates have been implemented: a) new chemistry-dependent low-temperature opacities b) up-to-date chemistry-dependent mass-loss prescriptions c) convective overshooting. With overshooting, envelope mixing will be more efficient and dredge-up additional material from deeper layers. The stellar surface will thus be converted from an oxygen- to a carbon-rich one, and changes will directly affect the opacities and in turn the mass-loss rates. While ignored in previous models, these transformations are now taken into account. We show, how such amendments were a necessity by comparing the results with older grids, and how models are in agreement, without any prior calibration, with observations. The new stellar library contains 100 AGB and 60 post-AGB sequences. The AGB tracks cover the entire parameter space. Post-AGB models are also available for the full metallicity range but, because of convergence issues, only for star between 1 and 2 solar masses. To our knowledge this work provides the scientific community with the most up-to-date, self-consistent and extended grid, originating from detailed AGB and post-AGB models. It is expected to be a valuable input-tool for population synthesis work and aims to supersede the more than 10-year old outdated tracks that are currently still being used
Baroclinic instability of two-layer vortices in laboratory experiments

The dynamics of a baroclinic vortex in a two-layer rotating stratified fluid is investigated. The vortex is produced by the classical geostrophic adjustment process, starting from an initial step in the layer interface. The experiments are performed on the 13m diameter Coriolis turntable, allowing investigation of inertial regimes, in which viscous friction effects are negligible. The velocity fields are measured in both layers by employing particle image velocimetry, thus providing a quantitative measure of the flow evolution. The baroclinic instability occurs much later in time than the initial inertial oscillations. The growth occurs in a hydrostatic regime, with velocity being independent of height in each layer. This process is described well by linear stability theory for a quasi-geostrophic disk vortex, or by the classical model of Phillips (1954) empirically adapted to the circular geometry. This stability prediction from the quasi-geostrophic model remains relevant even for a large initial interfacial step. For strong cyclones, the instability grows roughly twice as fast as these predictions. In the nonlinear stage of the instability, the initial vortex splits and reorganizes into vortex pairs propagating outward. These dipoles involve the interactions of positive and negative vortices, with components in the upper and in the lower layer. In the case of a large initial interface step, a clear asymmetry between anticyclones and cyclones is observed: the latter are more intense and compact, with a more barotropic structure. Our results are compared with numerical simulations, using a two-layer isopycnal model. Data assimilation is used to initiate the model with the same perturbations as in the laboratory experiments, thus providing a quantitative test of the dynamics. Furthermore, data assimilation is used to extrapolate the measurements, yielding the interface position and potential vorticity fields.
Solar-Radiation Heating Effects on 3200 Phaethon

Apollo-type near-Earth asteroid 3200 Phaethon, having a small perihelion distance of q � 0.14 AU, is classified as F- or B-type, one of subclasses among the C-complex (C-, G-, B-, and F-types) asteroids. The F/B-type asteroids and dehydrated CI and CM carbonaceous chondrites, which are regarded as being linked to each other, underwent a thermal history of high-temperature heatings at more than hundreds of degrees and dehydration for a certain period of time after aqueous alteration in their parent bodies. However, their primary heating mechanism and its timing are less certain and still controversial. We have investigated solar-radiation heating effects on Phaethon at the present planetary-epoch. As a consequence, we have found that the effects on Phaethon, if it is still hydrated, might indeed be a likely candidate for the primary metamorphic heat source. We also found that solar-radiation heating on Phaethon is a function of the latitude, since Phaethon has a highly tilted polar axis. Thus, the northern hemisphere would be selectively more heated than the southern hemisphere. Therefore, we hypothesized that the northern hemisphere, especially the north pole–northern midlatitude region, would be more thermally metamorphosed and dehydrated, if solar-radiation heating is the primary metamorphic heat source of Phaethon. This may provide the latitude-dependent color variations on Phaethon’s surface, although this has not been proven by the existing Phaethon’s spectral data.
Evaluation of sampling errors of precipitation from spaceborne and ground sensors

Abstract The spatial and temporal characteristics of rainfall over Oklahoma and Kansas are analyzed in this paper using the raingage data collected during the Preliminary Regional Experiment for STORM-Central (PRESTORM). The autocorrelation function and the spectrum are obtained directly from both processing the raingage data and using a theoretical stochastic model of spacetime precipitation. This theoretical model serves as an intermediate step to obtain more information from the raingage records. The spectra obtained are then compared with those obtained from oceanic precipitation in the GARP (Global Atmospheric Research Program) Atlantic Tropical Experiment (GATE) and with that obtained from analyzing raingage records in east Texas. Finally, the spectra are used to evaluate the sampling errors that are due to the spatial gaps in measurements. The sampling error is expressed as an integral over the product of the spectral density of the stochastic rain field and a filter function. This filter function.
Knot probability for lattice polygons in confined geometries

We study the knot probability of polygons confined to slabs or prisms, considered as subsets of the simple cubic lattice. We show rigorously that almost all sufficiently long polygons in a slab are knotted and we use Monte Carlo methods to investigate the behaviour of the knot probability as a function of the width of the slab or prism and the number of edges in the polygon. In addition we consider the effect of solvent quality on the knot probability in these confined geometries.
Swirling flow and its influence on dc arcs in a duo-flow hybrid circuit breaker

The effects of swirling flow on the behaviour of dc SF6 arcs in a duo-flow nozzle are computationally investigated in the electric current range 3–7 kA. A swirling flow is produced by the interaction of the magnetic field of a current-carrying coil and the plasma. Results show that a strong swirling flow is generated in regions where a large radial current density exists as a result of the conducting arc column rapidly changing its radial dimension. The presence of the swirling flow reduces the axis pressure, modifies the arc shape and slightly lowers the arc voltage (2–5%) in comparison with the case without considering the swirling flow. The different natures of swirling flows in a plasma jet/arc heater and in a hybrid circuit breaker are also discussed.
On Periodic and Multiple Autoregressions

Abstract : A methodology is presented for analyzing periodic autoregressions which is also applicable when inferring the second order properties of periodically correlated processes. In addition, capitalizing on the duality between periodic and multiple autoregressions, a method is set forth for analyzing the latter, which overcomes the usual requirements of a large number of both parameters and computer storage locations.
Sieve extremum estimates for weakly dependent data

Many non/semiparametric time series estimates may be regarded as different forms of sieve extremum estimates. For stationary absolute regular mixing observations, the authors obtain convergence rates of sieve extremurn estimates and root-n asymptotic normality of 'plug-in' sieve extremum estimates of smooth functionals. As applications to time series models, they give convergence rates for nonparametric ARX(p,q) regression via neural networks, splines, wavelets; root-n asymptotic normality for partial linear additive AR(p) models, and monotone transformation AR(1) models.
Equivalent Circuit of Interdigital Transducers Based on Coupling-of-Modes Theory Considering Electrode Resistivity and Propagation Loss.

An equivalent circuit of an interdigital transducer is derived from the coupling-of-modes equations considering propagation loss and resistivity of finger electrodes. The features of the circuit are discussed, focusing on the expression of the two loss mechanisms. As an example of calculations of device characteristics using the circuit derived, the frequency responses of insertion loss of a surface acoustic wave (SAW) resonator-coupled filter are shown with electrode resistivity as a parameter.
Economic Openness, Democracy, and Income Inequality

Scholars have studied effects of economic openness and democracy on national income inequality in two literatures. In democracy studies, scholars agree democracy reduces inequality but empirical evidence is ambiguous. In globalization studies, effects of economic openness on inequality are debated but have not been rigorously examined. This article is the first systematic statistical study of the effects of both economic openness and democracy on income inequality. These effects need to be studied together. The authors measure national income inequality from a comprehensive Gini coefficient data set. Economic openness is measured from trade flows, foreign direct investment inflows, and financial capital inflows. The period studied is 1960 to 1996, the unit of analysis is a country decade, and the sample includes 69 countries. The authors find that democracy and trade reduce income inequality, foreign direct investments increase income inequality, and financial capital does not affect income inequality. Policy implications are discussed.
Black Hole Binaries and X-Ray Transients

We consider transient behavior in low-mass X-ray binaries (LMXBs). We show that if this results from a disk instability, the secondary star must be significantly evolved when mass transfer starts, particularly if the primary is a neutron star. For P ≲ 2 days, most neutron star systems will be persistent X-ray sources, whereas the slower orbital evolution of black hole systems means that most of them are likely to be transient. Both types of transient system must have extreme mass ratios (<0.1). For orbital periods P ≳ 2 days, most LMXBs will be transient regardless of whether the primary is a neutron star or a black hole.
Hubble Space Telescope Imaging of the CFRS and LDSS Redshift Surveys. I. Morphological Properties

We analyze Hubble Space Telescope images of a complete sample of 341 galaxies drawn from the CFRS and LDSS ground-based redshift surveys. In this, the first paper in the series, each galaxy has been morphologically classified according to a scheme similar to that developed for the Medium Deep Survey. We discuss the reproducibility of these classifications and quantify possible biases that may arise from various redshift-dependent effects. We then discuss automated classifications of the sample and conclude, from several tests, that we can expect an apparent migration with redshift to later Hubble types that corresponds to a misclassification in our adopted machine classification system of ~24% ± 11 of the true "spirals" as "peculiars" at a redshift z ≃ 0.9. After allowing for such biases, the redshift distribution for normal spirals, together with their luminosity function derived as a function of redshift, indicates approximately 1 mag of luminosity evolution in BAB by z ≃ 1. The elliptical sample is too small for precise evolutionary constraints. However, we find a substantial increase in the proportion of galaxies with irregular morphology at large redshift from 9% ± 3% for 0.3 ≤ z ≤ 0.5 to 32% ± 12% for 0.7 ≤ z ≤ 0.9. These galaxies also appear to be the dominant cause of the rapid rise with redshift in the blue luminosity density identified in the redshift surveys. Although galaxies with irregular morphology may well comprise a mixture of different physical systems and might not correspond to present-day irregulars, it is clear that the apparently declining abundance and luminosities of our distant "irregulars" holds an important key to understanding recent evolution in the star formation history of normal galaxies.
On Some Semilinear Elliptic Problems with Singular Potentials Involving Symmetry

This paper deals with the existence and multiplicity of solutions for a class of semilinear elliptic problems of the form \begin{equation*} \begin{cases} \begin{array}{rlll} - \Delta u & =\displaystyle \frac{\mu}{|x|^2}u + f(x,u) & \text{ in } &\Omega, \\ u & = 0 & \text{ on } &\partial\Omega, \end{array} \end{cases} \end{equation*} where $\Omega = \Omega_1 \times \Omega_2 \subset \mathbb R^N$ ($N \geqq 5$) is a bounded domain having cylindrical symmetry, $\Omega_1 \subset \mathbb R^m$ is a bounded regular domain and $\Omega_2$ is a $k-$dimensional ball of radius $R$, centered in the origin and $m + k = N$, and $m \geqq 2$, $k \geqq 3$, $0 \leqq \mu < \mu^\star = \left(\frac{N-2}{2}\right)^2$. The proofs rely essentially on the critical point theory tools combined with the Hardy inequality.