Miracle-dz/UniFAR-FTUs huggingface dataset:
Reduction of quantum fluctuations by anisotropy fields in Heisenberg ferro‐ and antiferromagnets

The physical properties of quantum systems, which are described by the anisotropic Heisenberg model, are influenced by thermal as well as by quantum fluctuations. Such a quantum Heisenberg system can be profoundly changed towards a classical system by tuning two parameters, namely the total spin and the anisotropy field: Large easy‐axis anisotropy fields, which drive the system towards the classical Ising model, as well as large spin quantum numbers suppress the quantum fluctuations and lead to a classical limit. We elucidate the incipience of this reduction of quantum fluctuations. In order to illustrate the resulting effects we determine the critical temperatures for ferro‐ and antiferromagnets and the ground state sublattice magnetization for antiferromagnets. The outcome depends on the dimension, the spin quantum number and the anisotropy field and is studied for a widespread range of these parameters. We compare the results obtained by: Classical Mean Field, Quantum Mean Field, Linear Spin Wave and Random Phase Approximation. Our findings are confirmed and quantitatively improved by numerical Quantum Monte Carlo simulations. The differences between the ferromagnet and antiferromagnet are investigated. We finally find a comprehensive picture of the classical trends and elucidate the suppression of quantum fluctuations in anisotropic spin systems. In particular, we find that the quantum fluctuations are extraordinarily sensitive to the presence of small anisotropy fields. This sensitivity can be quantified by introducing an “anisotropy susceptibility”.
Functionalized MWCNT and PVA Nanocomposite Membranes for Dielectricand Pervaporation Applications

Novel PVA nanocomposite membranes were prepared with acid functionalized multiwalled carbon nanotubes (a-MWCNT) as the reinforcing material. The presence of functional groups on MWCNT is revealed by FTIR techniques. The excess swelling of poly (vinyl alcohol) (PVA) membranes were reduced by the crosslinking of glutraldehyde (GA). The functionalized MWCNT induces hydrophilicity to the PVA nanocomposites and the hydrophilic nature of the nanocomposites was revealed by the contact angle analysis. The effect of a-MWCNT concentration on the dielectric and DC conductivities of the PVA nanocomposites was studied very well. The electrical conductivity of the nanocomposites is increased with the concentration of MWCNT, and PVA with 1.5 wt% nanotube loaded membranes showed better dielectric properties. As the concentration of MWCNT increased to 1.5 wt%, the PVA nanocomposites got transformed from a region of insulator to semiconductor. DC conductivity also showed the same trend. The Voet model showed good agreement with the experimental results of the conductivity. We also found that the developed PVA/a-MWCNT nanocomposite membranes can be used to separate the azeotropic composition of water-ethanol mixtures. The pervaporation (PV) performance of the membranes is studied in terms of permeance and intrinsic selectivity. PVA with 0.5 wt% nanotube loaded nanocomposite membranes achieved 340% increment in intrinsic selectivity. The pervaporation performance of the membranes were in good agreement with the permeation ratio model, and the separation efficiency is influenced by the morphology of the membranes and the interaction of the filler and the permeates. It is also observed that the dielectric properties of the membranes were correlated with the concentration of the conductive nanofillers. Thus the present study provides good information on dielectric and the pervaporation performance of PVA/a-MWCNT nanocomposite membranes.
Depolarization properties of the normal human fovea measured by the GDx-MM

A custom imaging Mueller matrix retinal polarimeter (the GDx-MM) is built. Mueller matrix images of normal human fovea were acquired with the GDx-MM over a 9° field at 780nm and have been analyzed for depolarization index and the variation of degree of polarization with incident polarization state. The degree of polarization (DoP) was often above 50% and varied in complex ways as a function of the incident polarization states. The depolarization properties around the macula loosely correlated with the retardance image. High spatial frequency depolarizing structures were evident throughout the fovea.
Contributions to the implementation of the Arakawa-Schubert cumulus parameterization in the GLA GCM

Abstract Several integrations were made with a coarse (4° × 5° nine-sigma level) version of the GLA GCM, which has the Arakawa–Schubert cumulus parameterization, predicted fractional cloud cover, and a parameterization of evaporation of falling rainfall. All model simulation experiments started from the ECMWF analysis for 15 December 1982 and were integrated until 31 January 1983 using climatological boundary conditions. The first ten days of model integrations show that the model-simulated tropics dries and warms as a result of excessive precipitation. Three types of model development-cum-analysis studies were made with the cumulus scheme. First, the Critical Cloud Work Function (CCWF) dataset for different sigma layers were reworked using the Cloud Work Function (CWF) database of Lord et al. as representative of time-average CWF and not the actual CCWF values as in the Arakawa–Schubert implementation of cumulus convection. The experiments with the new CCWF dataset helped to delineate the influence of ch.
On the Chemical Abundances of Multiple-Shell Planetary Nebulae with Halos

We present narrowband imagery and long-slit intermediate-resolution spectroscopy of the multiple-shell planetary nebulae NGC 2438 and NGC 5882. A comparative study of the chemical abundances of the main nebulae and their surrounding halos shows a moderate N/O enrichment of the central regions. The oxygen abundances appear constant throughout the nebulae, but there are some indications of a moderate helium enrichment in the NGC 5882 main nebula. This study, along with with data published in the literature for six other multiple-shell planetary nebulae (M1-46, NGC 6543, NGC 6720, NGC6751, NGC 6826, and NGC 7662), provides insight into the chemical enrichment and physical conditions of halos. All the nebulae in this sample have chemical abundances typical of type II planetary nebulae, thus indicating a small chemical enrichment. In addition, we do not find evidence to support a strong chemical enrichment of the main nebulae relative to the halos. The conclusion is that the third dredge-up, in these nebulae, is of small or null effect. Finally, we find a clear evidence that the gas in the halos is ionized by stellar UV radiation leaking through the material of the main nebula.
Spatial evolution of turbulence characteristics in weak hydraulic jumps

This experimental investigation focuses on the turbulence features of weak hydraulic jumps in rectangular channels for two different approach flow lengths. The turbulent kinetic energy equation includes the turbulence production and dissipation terms, two advection and two turbulent transport terms and the pressure transport term, which could not be measured, however. For jumps with a limited approach flow length, the turbulence production is mostly confined to the shear layer, while for jumps with a longer approach flow length, an additional peak turbulence production region is observed at the near-wall region due to boundary layer separation. The turbulent energy is then transported by the mean flow both towards the free surface and into the downstream direction and is diffused by turbulent processes away from the energetic shear layer towards less energetic regions. Dissipation occurs mostly in the shear layer along the upstream portion of the jump and over most of the flow depth further downstream.
Radiative lifetimes, branching fractions and oscillator strengths in Pd I and the solar palladium abundance

Transition probabilities have been derived for 20 5s−5p transitions of Pd I from a combination of radiative lifetime measurements for 6 odd-parity levels with time-resolved laser-induced fluorescence spectroscopy and of branching fraction determination using a hollow cathode discharge lamp. Additional oscillator strengths for 18 transitions have been determined from measured lifetimes and theoretical branching fractions obtained from configuration interaction calculations with core-polarization effects included. These new results have allowed us to refine the palladium abundance in the solar photosphere: APd = 1.66 ± 0.04, in the usual logarithmic scale, a result in close agreement with the meteoritic value.
Ar ion milling process for fabricating CoCrPt patterned media using a self-assembled PS-PMMA diblock copolymer mask

Etching the damage of a patterned media fabricated with an artificially assisted self-assembled mask is estimated. CoCrPt thin films were etched by ion milling into aligned dots with a diameter of 40 nm. The milling condition was optimized for reducing the etching damage. As a result, the damage to the crystal lattice and crystal orientation was estimated to be slight by transmission electron microscope (TEM) and scanning electron microscope (SEM) analyses. Though strong perpendicular anisotropy was induced by the patterning process, magnetic measurements and Landau-Lifshitz-Gilbert simulation revealed that the magnetic anisotropy energy was almost unchanged throughout this etching process.
The MUSE project from the dream toward reality

MUSE (Multi Unit Spectroscopic Explorer) is a second generation instrument developed for ESO (European Southern Observatory) to be installed on the VLT (Very Large Telescope) in year 2012. The MUSE project is supported by a European consortium of 7 institutes. After a successful Final Design Review the project is now facing a turning point which consist in shifting from design to manufacturing, from calculation to test, . from dream to reality. At the start, many technical and management challenges were there as well as unknowns. They could all be derived of the same simple question: How to deal with complexity? The complexity of the instrument, of the work to de done, of the organization, of the interfaces, of financial and procurement rules, etc. This particular moment in the project life cycle is the opportunity to look back and evaluate the management methods implemented during the design phase regarding this original question. What are the lessons learn? What has been successful? What could have been done differently? Finally, we will look forward and review the main challenges of the MAIT (Manufacturing Assembly Integration and Test) phase which has just started as well as the associated new processes and evolutions needed.
A Comparison of Coma Cluster S0 Galaxies with the Tully-Fisher Relation for Late-Type Spirals

We present I-band photometry for 13 S0 galaxies in the Coma Cluster and estimate their circular velocities based on stellar kinematics derived from stellar absorption-line spectroscopy. We find that there is at most a small offset, ΔmI ≤ 0.2, in the I-band luminosity at a given circular velocity, vc ∼ 200 km s-1, between late-type spirals and the S0 galaxies studied here. This result implies a similar total I-band mass-to-light ratio (within an effective radius) among disk galaxies of rather different Hubble types. As the older stellar population in S0's is dimmer, this suggests a somewhat larger fraction of stellar mass in these S0's than in late-type spirals. We also find that the relation between I-band luminosity and vc for the S0 galaxies is at best poorly defined and has a scatter of σI ∼ 0.5 mag, significantly larger than the Tully-Fisher relation (TFR) for late-type spirals in clusters, where the observed I-band scatter is σI ≲ 0.3 mag. This substantial scatter is only somewhat less than that found by Neistein et al. in a recent study of 18 nearby S0 galaxies in the field (σI ∼ 0.7 mag), implying that no tight TFR holds for field S0 galaxies. These results suggest that differing formation histories can lead to S0's with diverse properties. Our analysis of S0's in the Coma Cluster differs from previous analyses in two important respects: the data are independent of distance estimate errors, and they contain S0's formed in a more homogeneous environment.
Structural and Electronic Properties of Bixo 3 (X = Mn, Fe, Cr)

The candidate multiferroic BiCrO3 and its chemical neighbors BiMnO3 and BiFeO3 are known to be ferromagnetic and ferroelectric respectively. With structural distortions driven by the strongly polarizable Bi ions, we present results of the first-principles density functional calculations using the (FP-LMTO) method with the spin-orbit coupling for those materials in the pseudo-cubic perovskite phase. The results showed that the valence bands in these compounds are formed by the 6p orbitals of bismuth and 3d orbital’s of the transition metals. Our results indicate that these materials have metallic behavior for spin-up polarization but being a clear tandance for semiconductor spin-down BiMnO3.
The relationship between chloride migration rate for concrete and charge passed rate in accelerated chloride migration test

Abstract The main objective of this study was to evaluate the correlation between chloride migration rate and the charge passed rate for concrete. The electrochemical technique is applied to accelerate chloride ion migration in concrete to obtain chloride migration rate and the charge passed rate. In this study, the plain cement concrete and concrete containing different types of mineral admixtures (fly ash and slag) with w/b ratios of 0.35, 0.45, 0.55, and 0.65 were used. A good correlation between chloride migration rate and charge passed rate obtained from the accelerated chloride migration test in the steady state was found. In order to avoid sampling and analyzing chlorides during the migration test, the procedure of determining the chloride migration rate by measuring the charge passed seems valid.
Foreign aid and export diversification in developing countries

This paper analyzes the effect of foreign aid on export diversification for a sample of developing countries while controlling for the effects of other factors that determine export diversification. We find that foreign aid not exceeding 20% of a country's GDP significantly promotes export diversification, while foreign aid in excess of 20% of GDP significantly impedes export diversification. The latter result corroborates evidence from related literature, which has shown that foreign aid can have an anti-export bias due to a Dutch disease effect. However, our results show that aid as a percent of GDP is below 20% in most low-income countries. This implies that in many low-income countries, varying amounts of additional aid can be used to enhance export diversification without causing a Dutch disease effect. As in the previous literature, we find that the level of development, infrastructure, transactions costs, and natural resources significantly affect export diversification. Our results are robust to the use of two different export diversification measures and different sub-samples.
Composition and azimuthal spread of solar energetic particles from impulsive and gradual flares

We began with a list of 77 flare-associated solar energetic particle (SEP) events observed from 1974 to 1985 by at least one of the two Helios space probes. We classified the SEP parent flares as impulsive (25 cases) or gradual (52 cases) on the basis of their soft X-ray durations. We then compared the intensities of the prompt component of ∼0.5 MeV electrons, ∼10 MeV protons, and ∼10 MeV per nucleon helium for the two classes of SEP flares. We find that SEPs from gradual flares have higher intensities than SEPs from impulsive flares
The Economics of Sustainable Land Management Practices in the Ethiopian Highlands

This article uses data from household- and plot-level surveys conducted in the highlands of the Tigray and Amhara regions of Ethiopia. We examine the contribution of sustainable land management (SLM) practices to net value of agricultural production in areas with low vs. high agricultural potential. A combination of parametric and non-parametric estimation techniques is used to check result robustness. Both techniques consistently predict that minimum tillage (MT) is superior to commercial fertilisers (CFs), as are farmers' traditional practices (FTPs) without CFs, in enhancing crop productivity in the low agricultural potential areas. In the high agricultural potential areas, in contrast, use of CFs is superior to both MT and FTPs without CFs. The results are found to be insensitive to hidden bias. Our findings imply a need for careful agro-ecological targeting when developing, promoting and scaling up SLM practices. Copyright (c) 2010 The Authors. Journal compilation (c) 2010 The Agricultural Economics Society.
Volumetric spatial feature representation for view-invariant human action recognition using a depth camera

Abstract. The problem of viewpoint variations is a challenging issue in vision-based human action recognition. With the richer information provided by three-dimensional (3-D) point clouds thanks to the advent of 3-D depth cameras, we can effectively analyze spatial variations in human actions. In this paper, we propose a volumetric spatial feature representation (VSFR) that measures the density of 3-D point clouds for view-invariant human action recognition from depth sequence images. Using VSFR, we construct a self-similarity matrix (SSM) that can graphically represent temporal variations in the depth sequence. To obtain an SSM, we compute the squared Euclidean distance of VSFRs between a pair of frames in a video sequence. In this manner, an SSM represents the dissimilarity between a pair of frames in terms of spatial information in a video sequence captured at an arbitrary viewpoint. Furthermore, due to the use of a bag-of-features method for feature representations, the proposed method efficiently handles the variations of action speed or length. Hence, our method is robust to both variations in viewpoints and lengths of action sequences. We evaluated the proposed method by comparing with state-of-the-art methods in the literature on three public datasets of ACT42, MSRAction3D, and MSRDailyActivity3D, validating the superiority of our method by achieving the highest accuracies.
Some Further Generalizations of the Hyers–Ulam–Rassias Stability of Functional Equations

Abstract In this paper we study the Hyers–Ulam–Rassias stability theory by considering the cases where the approximate remainder φ is defined by f x ∗ y − f x − f y = φ x , y ∀ x , y ∈ G , 1 f x ∗ y − g x − h y = φ x , y ∀ x , y ∈ G , 2 2f x ∗ y 1/2 − f x − f y = φ x , y ∀ x , y ∈ G , 3 where ( G , ∗ ) is a certain kind of algebraic system, E is a real or complex Hausdorff topological vector space, and f , g , h are mappings from G into E . We prove theorems for the Hyers–Ulam–Rassias stability of the above three kinds of functional equations and obtain the corresponding error formulas.
Modeling of giant magnetoresistance isolator for high speed digital data transmission utilizing spin valves

Giant magnetoresistance isolator was modeled for effective transmission of high speed digital data, and the output voltage characteristics depending on pulse width of input signal, inductor coil turn, and existence of external circuit of the planar inductor were investigated in time domain. The planar coil was modeled as a lumped element R,L,C circuit and the coil current was calculated using SPICE. The corresponding magnetic field was substituted to the measured magnetoresistance-H curve to obtain the resistance values of the spin valves, which were used to obtain the output voltage wave form of the isolator. Effective maximum transmission speed of 250Mbit∕s was estimated. Even though the coil current wave form was much deformed with damping, the transmitted output voltage wave form was very close to the rectangular wave form of the input signal due to hysteretic characteristics of the spin valves.
Review of VSG Control-Enabled Universal Compatibility Architecture for Future Power Systems with High-Penetration Renewable Generation

Due to the irreversible energy substitution from fossil fuels to clean energy, the development trend of future power systems is based on renewable energy generation. However, due to the incompatibility of converter-based non-dispatchable renewable energy generation, the stability and reliability of traditional power systems deteriorate as more renewables are introduced. Since conventional power systems are dominated by synchronous machines (SM), it is natural to utilize a virtual synchronous generator (VSG) control strategy that intimates SM characteristics on integrated converters. The VSG algorithm developed in this paper originates from mimicking mathematic models of synchronous machines. Among the different models of implementation, the second-order model is simple, stable, and compatible with the control schemes of current converters in traditional power systems. The VSG control strategy is thoroughly researched and case studied for various converter-interfaced systems that include renewable generation, energy storage, electric vehicles (EV), and other energy demands. VSG-based integration converters can provide grid services such as spinning reserves and inertia emulation to the upper grids of centralized plants, distributed generation networks, and microgrids. Thus, the VSG control strategy has paved a feasible way for an evolutionary transition to a power electronics-based future power grid. By referring to the knowledge of traditional grids, a hierarchical system of operations can be established. Finally, generation and loads can be united in universal compatibility architecture under consolidated synchronous mechanisms.
Quasar ionization of Lyman-alpha clouds - The proximity effect, a probe of the ultraviolet background at high redshift

The distribution of lines in the Ly-alpha forests in quasar spectra is examined using spectral data from 19 quasars with emission lines redshifts z sub Q ranging from 1.7 to 3.8. The number density of Ly-alpha lines generally increases with resdhift z, but there exists a countervailing trend of diminishing number density within individual quasar spectra as z tends to z sub Q. Evidence is presented that this countervailing trend is due to enhanced ionization of Ly-alpha clouds by the bright nearby quasars in whose spectra they are observed. It is suggested that this proximity effect should be used as a powerful tool to measure locally the ionizing flux emitted by high-redshift objects. 44 references.
Multiscale large eddy states in weakly stratified planetary boundary layers

Abstract We first discuss observations of two classes of two-dimensional large eddy states in weakly stratified atmospheric boundary layers. One class is characterized by large eddies with a single horizontal scale. The other contains multiscale large eddies, with horizontal wavelengths on the order of the boundary layer depth (as generally supported by spectra), coexisting with scales that are several times this depth (as generally seen in cloud street patterns). We then present a theory which describes these different large eddy states as the result of wave–wave interactions between growing disturbances in the planetary boundary layer. We develop nonlinear, coupled evolution equations that govern the temporal evolution of a set of three isolated disturbances of initial eigenmode form in a general unstable flow. These equations model both wave/wave and wave/mean flow interactions. They imply that in unstable flow regimes, modes with relatively large growth rates as predicted by linear theory act as catal.