Miracle-dz/UniFAR-FTUs huggingface dataset:
Comparison of caloric effects in view of application

In the framework of solid-state cooling technology, four kinds of caloric effects, magnetocaloric (MC), electrocaloric (EC), barocaloric (BC) and elastocaloric (eC) effects, are compared in view of environment discussion and application fields. This field is primarily developed in the intention of protecting the environment. However, some widely researched caloric materials do not meet environmental friendly criteria. Currently, new caloric materials (called “good” material) possessing the properties of friendly environment, low cost, high caloric performance and practicability (low stress) need to be found. In view of application, all current caloric effects/materials are investigated for the common objective of cooling. However, the adapted application cases for different caloric effects/materials are not considered. Due to the different stimuli and different intrinsic properties (different caloric performance for different dimensions) of caloric materials, they can exhibit unique advantage to different application cases. “Good” caloric material used for large-scale application is still less and deserve more search. Purposeful research will save the cost and accelerate the commercialization.
Models of the compact jet in GRS 1915+105

In this article, models are constructed of the compact jet in GRS 1915+105 during an epoch of optimal data capture. On 2003 April 2, the object was observed in the hard X-ray/soft gamma-ray band (INTEGRAL), hard X-ray band (RXTE), near-IR (ESO/New Technology Telescope) and the Very Long Baseline Array (VLBA) (8.3 and 15 GHz). The source was in a so-called ‘high plateau state’. The large radio flux provides high signal-to-noise ratios in the radio images. Thus, one can image the jet out to large distances (>1015 cm). This combined with the broad-band coverage make this epoch the best suited for modelling the jet. The parametric method that has been successfully utilized in the realm of extragalactic radio jets is implemented. The basic model is one where external inverse Compton (EIC) scattering of accretion disc photons by jet plasma provides the hard X-ray power law. Unlike active galactic nucleus (AGN) jets, it is found that the radio jet must be highly stratified in the transverse direction in order to produce the observed surface brightness distribution in the radio images. Various jet models are considered. The jet power is Q ≈ 3–4 × 1038 erg s−1 if the hard X-ray power-law luminosity is from EIC in the jet and Q ≈ 2–9 × 1037 erg s−1 if the X-rays are emitted from the accretion disc corona. These estimates indicate that the jet power can be as high as 60 per cent of the total X-ray luminosity.
Minimizing Wheel Slip in Railway Locomotives with Coupled Permanent Magnet Synchronous Motors

In this work I consider control strategies of permanent magnet synchronous motors in which the back-emf signal from the motor is used to achieve commutation of the six step driving circuit. I show that if the strategy is modified to connect multiple motors in a cyclic chain, then a collective synchronized state is favoured. The stability of this state can be exploited in the bogies of a railway locomotive to automatically terminate wheel slipping episodes.
Time and Wavelength Division Multiplexing Passive Optical Network Comparative Analysis: Modulation Formats and Channel Spacings

 Abstract — In light of the substantial increase in end-user requirements and the incessant need of network operators to upgrade the capabilities of access networks, in this paper, the performance of the different modulation formats on eight-channels Time and Wavelength Division Multiplexing Passive Optical Network (TWDM-PON) transmission system has been examined and compared. Limitations and features of modulation formats have been determined to outline the most suitable design to enhance the data rate and transmission reach to obtain the best performance of the network. The considered modulation formats are On-Off Keying Non-Return-to-Zero (NRZ-OOK), Carrier Suppressed Return to Zero (CSRZ), Duo Binary (DB), Modified Duo Binary (MODB), Quadrature Phase Shift Keying (QPSK), and Differential Quadrature Phase Shift Keying (DQPSK). The performance has been analyzed by varying transmission distances and bit rates under different channel spacing. Furthermore, the system is evaluated in terms of minimum Bit Error Rate (BER) and Quality factor (Qf) without applying any dispersion compensation technique, or any optical amplifier. Optisystem software was used for simulation purposes.
NEW MEMBERS OF THE SCORPIUS-CENTAURUS COMPLEX AND AGES OF ITS SUB-REGIONS

We have spectroscopically identified ∼100 G-, K-, and M-type members of the Scorpius-Centaurus complex. To deduce the age of these young stars we compare their Li λ6708 absorption line strengths against those of stars in the TW Hydrae association and β Pictoris moving group. These line strengths indicate that Sco-Cen stars are younger than β Pic stars whose ages of ∼12 Myr have previously been derived from a kinematic traceback analysis. Our derived age, ∼10 Myr, for stars in the Lower Centaurus Crux and Upper Centaurus Lupus subgroups of ScoCen is younger than previously published ages based on the moving cluster method and upper main-sequence fitting. The discrepant ages are likely due to an incorrect (or lack of) cross-calibration between model-dependent and model-independent age-dating methods.
On a measure of distance for quantum strategies

The present paper studies an operator norm that captures the distinguishability of quantum strategies in the same sense that the trace norm captures the distinguishability of quantum states or the diamond norm captures the distinguishability of quantum channels. Characterizations of its unit ball and dual norm are established via strong duality of a semidefinite optimization problem. A full, formal proof of strong duality is presented for the semidefinite optimization problem in question. This norm and its properties are employed to generalize a state discrimination result of Gutoski and Watrous [In Proceedings of the 22nd Symposium on Theoretical Aspects of Computer Science (STACS’05), Lecture Notes in Computer Science, Vol. 3404 (Springer, 2005), pp. 605–616. The generalized result states that for any two convex sets S0, S1 of strategies there exists a fixed interactive measurement scheme that successfully distinguishes any choice of S0 ∈ S0 from any choice of S1 ∈ S1 with bias proportional to the minim.
Enhanced entanglement criterion via symmetric informationally complete measurements

We show that a special type of measurements, called symmetric informationally complete positive operator-valued measures (SIC POVMs), provide a stronger entanglement detection criterion than the computable cross-norm or realignment criterion based on local orthogonal observables. As an illustration, we demonstrate the enhanced entanglement detection power in simple systems of qubit and qutrit pairs. This observation highlights the significance of SIC POVMs for entanglement detection.
A Systematic Comparison of Tropical Waves over Northern Africa. Part II: Dynamics and Thermodynamics

This study presents the first systematic comparison of the dynamics and thermodynamics associated with all major tropical wave types causing rainfall modulation over northern tropical Africa: the Madden–Julian oscillation (MJO), equatorial Rossby waves (ERs), tropical disturbances (TDs, including African easterly waves), Kelvin waves, mixed Rossby–gravity waves (MRGs), and eastward inertio-gravity waves (EIGs). Reanalysis and radiosonde data were analyzed for the period 1981–2013 based on space–time filtering of outgoing longwave radiation. The identified circulation patterns are largely consistent with theory. The slow modes, MJO and ER, mainly impact precipitable water, whereas the faster TDs, Kelvin waves, and MRGs primarily modulate moisture convergence. Monsoonal inflow intensifies during wet phases of the MJO, ERs, and MRGs, associated with a northward shift of the intertropical discontinuity for MJO and ERs. This study reveals that MRGs over Africa have a distinct dynamical structure that differs significantly from AEWs. During passages of vertically tilted imbalanced wave modes, such as the MJO, TDs, Kelvin waves, and partly MRG waves, increased vertical wind shear and improved conditions for up- and downdrafts facilitate the organization of mesoscale convective systems. The balanced ERs are not tilted, and rainfall is triggered by large-scale moistening and stratiform lifting. The MJO and ERs interact with intraseasonal variations of the Indian monsoon and extratropical Rossby wave trains. The latter causes a trough over the Atlas Mountains associated with a tropical plume and rainfall over the Sahara. The presented results unveil which dynamical processes need to be modeled realistically to represent the coupling between tropical waves and rainfall in northern tropical Africa.
Nonlinear Image Formation by Optical Superlattices

The angular spectrum theory is applied to the nonlinear harmonic generation process in optical superlattices. Several explicit and analytical structure functions are deduced to design optical superlattices for various purposes. Employing this method, nonlinear image formation is achieved during the second-harmonic generation process in a properly designed optical superlattice. This method is universal for both nonlinear beam shaping and nonlinear arbitrary image formation. The theory has been experimentally validated in two-dimensional optical superlattice of LiTaO3 crystals and the results agree well with the theoretical prediction. This work not only extends the application of optical superlattices, but also opens a new area for imaging technologies.
Distortion of Magnetic Fields in a Starless Core. V. Near-infrared and Submillimeter Polarization in FeSt 1-457

The relationship between submillimeter dust emission polarization and near-infrared (NIR) H-band polarization produced by dust dichroic extinction was studied for the cold starless dense core FeSt 1–457. The distributions of polarization angles (90°-rotated for the submillimeter) and degrees were found to be very different between submillimeter and NIR wavelengths. The mean polarization angles for FeSt 1-457 at submillimeter and NIR wavelengths are 132. °1 ± 22. °0 and 2. °7 ± 16. °2, respectively. The correlation between PH and AV was found to be linear from the outermost regions to the relatively dense lines of sight of AV ≈ 25 mag, indicating that NIR polarization reflects the overall polarization (magnetic field) structure of the core, at least in this density range. The flat PH/AV versus AV correlations were confirmed, and the polarization efficiency was found to be comparable to the observational upper limit. On the other hand, as reported by Alves et al. submillimeter polarization degrees show a clear linearly decreasing trend against AV from AV ≈ 20 mag to the densest center (AV ≈ 41 mag), appearing as a “polarization hole” structure. The power-law index for the Psubmm versus AV relationship was obtained to be ≈−1, indicating that the alignment for the submillimeter-sensitive dust is lost. These very different polarization distributions at submillimeter and NIR wavelengths suggest either that (1) there are different radiation environments at these wavelengths or (2) submillimeter-sensitive dust is localized or (3) a combination of both.
LEP Shines Light on Dark Matter

Dark matter pair production at high energy colliders may leave observable signatures in the energy and momentum spectra of the objects recoiling against the dark matter. We use LEP data on mono-photon events with large missing energy to constrain the coupling of dark matter to electrons. Within a large class of models, our limits are complementary to and competitive with limits on dark matter annihilation and on WIMP-nucleon scattering from indirect and direct searches. Our limits, however, do not suer from systematic and astrophysical uncertainties associated with direct and indirect limits. For example, we are able to rule out light (. 10 GeV) thermal relic dark matter with universal couplings exclusively to charged leptons. In addition, for dark matter mass below about 80 GeV, LEP limits are stronger than Fermi constraints on annihilation into charged leptons in dwarf spheroidal galaxies. Within its kinematic reach, LEP also provides the strongest constraints on the spin-dependent direct detection cross section in models with universal couplings to both quarks and leptons. In such models the strongest limit is also set on spin independent scattering for dark matter masses below 4 GeV. Throughout our discussion, we consider both low energy eective theories of dark matter, as well as several motivated renormalizable scenarios involving light mediators.
Fast Harmonic compensation in hybrid HVDC offshore system

Hybrid HVDC systems have been proposed as an alternative for nominal VSC-Based HVDC for offshore applications. Hybrid HVDC systems consist of an offshore power station composed of the connection of high-power diode rectifiers in series with a fractional power VSC-HVDC. This hybrid configuration allows large power transfer from offshore sites, with the added robustness, simplicity and efficiency of uncontrolled rectifiers. In this research, a robust and fast-acting controller, the Two Degrees of Freedom Internal Model controller (2DF-IMC), is used to control the active power filter features of the fractional-power VSC-HVDC system, resulting in a much faster overall THD reduction in the offshore AC currents in dynamic conditions (i.e. time-varying wind power) when compared with standard active power filter controllers. This improvement is the direct consequence of the fast closed-loop dynamics of the 2DF-IMC controller that do not require filtering stages. Additionally, the increased closed-loop response time did not affect the overall robustness of the control system, thanks to the enhanced disturbance rejection capabilities of the 2DF-IMC configuration.
Corticostriatal connectivity mediates the reciprocal relationship between sleep and impulsivity in early adolescents

Background: Adolescence, a developmental period characterized by major changes in sleep and circadian rhythms, is associated with normative increases in impulsivity. While insufficient sleep has been linked to elevated impulsivity, the neural mechanism underlying the relationship remains poorly understood. Methods: We analyzed a dataset of 7,884 drug-naive 9-10 year-olds from the Adolescent Brain Cognitive Development (ABCD) study. Among them, 5,166 have 2-year follow-up neuroimaging data. Linear mixed-effects models, mediation analysis, and longitudinal mediation analysis were used to investigate the relationship between sleep, impulsivity, and brain functional and structural connectivity between the cortex and the striatum. Results: We found that less sleep is significantly associated with higher impulsivity and disrupted functional connectivity between the cingulo-opercular network and the left caudate, and between the cingulo-parietal network and the right pallidum. These two connectivity measurements mediate the effect of sleep duration on impulsivity at both baseline and two-year follow-up. Longitudinal mediation analyses further revealed that sleep duration and impulsivity can reinforce each other through cortical-striatum connectivities in a reciprocal manner. Conclusions: These results reveal neural mechanisms underlying the robust reciprocal relationship between insufficient sleep and impulsivity. Our findings highlight the role of early sleep intervention in helping early adolescents control their impulses, which might in turn prevent the development of substance use.
Comparison of laboratory wave generation techniques on response of a large monopile in irregular sea

As the offshore wind industry moves toward larger monopile turbines, model testing and validation of hydrodynamic load models become more important for new designs of turbines. Wave generation is an important aspect of hydrodynamic model testing. When generating irregular waves with a piston-type wavemaker, first order wavemaker theory is commonly used. This leads to generating spurious free waves in the tank. Using second order wavemaker theory reduces the generation of these spurious waves. In this study, the two wave generation techniques have been used in the measurement of the dynamic responses of a monopile with (full-scale) natural period of 5 sec. The effect of superharmonic spurious waves on the response statistics was minor. A marginal improvement in experimental repeatability of the second mode response in large wave events was observed by using second order wavemaker theory.
X-ray spectroscopy of the Virgo Cluster out to the virial radius

We present results from the analysis of a mosaic of 13 XMM–Newton pointings covering the Virgo Cluster from its centre northwards out to a radius r ∼ 1.2 Mpc (∼4. ◦ 5), reaching the virial radius and beyond. This is the first time that the properties of a modestly sized (Mvir ∼ 1.4 × 10 14 M� , kT ∼ 2.3 keV), dynamically young cluster have been studied out to the virial radius. The density profile of the cluster can be described by a surprisingly shallow power-law ne ∝ r −β with index β = 1.21 ± 0.12. In the radial range of 0.3rvir < r < rvir, the best-fitting temperature drops by roughly 60 per cent. Within a radius r < 450 kpc, the entropy profile has an approximate power law form K ∝ r 1.1 , as expected for gravitationally collapsed gas in hydrostatic equilibrium. Beyond r ∼ 450 kpc, however, the temperature and metallicity drop abruptly, and the entropy profile becomes flatter, staying consistently below the expected value by a factor of 2–2.5. The most likely explanation for the unusually shallow density profile and the flattening of entropy at large radius is clumping in the ICM. Our data provide direct observational evidence that the ICM is enriched by metals all the way to r200 to at least Z = 0.1 Z � .
A complete analytic gravitational wave model for undergraduates

Gravitational waves are produced by orbiting massive binary objects, such as black holes and neutron stars, and propagate as ripples in the very fabric of space-time. As the waves carry off orbital energy, the two bodies spiral into each other and eventually merge. They are described by Einstein’s equations of general relativity. For the early phase of the orbit, called the inspiral, Einstein equations can be linearised and solved through analytical approximations, while for the late phase, near the merger, we need to solve the fully nonlinear Einstein’s equations on supercomputers. In order to recover the gravitational wave for the entire evolution of the binary, a match is required between the inspiral and the merger waveforms. Our objectives are to establish an educational oriented toy model for a streamlined matching method, that will allow an analytical calculation of the complete gravitational waveform, while developing a gravitational wave modelling tutorial for undergraduate physics students. We use post-Newtonian (PN) theory for the inspiral phase, which offers an excellent training ground for students, and rely on Mathematica for our calculations, a tool easily accessible to undergraduates. For the merger phase we bypass Einstein’s equations by using a simple analytic toy model named the implicit rotating source. After building the inspiral and merger waveforms, we construct our matching method and validate it by comparing our results with the waveforms for the first detection, GW150914, available as open source. Several future projects can be developed based from this project: building complete waveforms for all the detected signals, extending the PN model to take into account non-zero eccentricity, employing and testing a more realistic analytic model for the merger, building a separate model for the ringdown, and optimising the matching technique.
Ultrahigh sensitivity magnetic field and magnetization measurements with an atomic magnetometer

We describe an ultrasensitive atomic magnetometer based on optically pumped potassium atoms operating in a spin-exchange relaxation free regime. We demonstrate magnetic field sensitivity of 160 aT/Hz1/2 in a gradiometer arrangement with a measurement volume of 0.45 cm3 and energy resolution per unit bandwidth of 44ℏ. As an example of an application enabled by such a magnetometer, we describe measurements of weak remnant rock magnetization as a function of temperature with a sensitivity on the order of 10−10 emu/cm3/Hz1/2 and temperatures up to 420°C.
Intrinsic defect formation in peptide self-assembly

In contrast to extensively studied defects in traditional materials, we report here a systematic investigation of the formation mechanism of intrinsic defects in self-assembled peptide nanostructures. The Monte Carlo simulations with our simplified dynamic hierarchical model revealed that the symmetry breaking of layer bending mode at the two ends during morphological transformation is responsible for intrinsic defect formation, whose microscopic origin is the mismatch between layer stacking along the side-chain direction and layer growth along the hydrogen bond direction. Moreover, defect formation does not affect the chirality of the self-assembled structure, which is determined by the initial steps of the peptide self-assembly process.
The Fornax Cluster VLT Spectroscopic Survey – I. VIMOS spectroscopy of compact stellar systems in the Fornax core region

We present the results of a wide spectroscopic survey aimed at detecting extragalactic globular clusters (GCs) in the core of the Fornax cluster. About 4500 low-resolution spectra (from 4800 to 10000 A) were observed in 25 VLT/VIMOS masks covering the central 1 deg(-2) around the dominant galaxy NGC 1399 corresponding to similar to 175 kpc galactocentric radius. We describe the methodology used for data reduction and data analysis. We found a total of 387 unique physical objects (372 GCs and 15 ultracompact dwarfs) in the field covered by our observations. Most of these objects lie in the region of NGC 1399 halo, with only 10 per cent likely belonging to other giant galaxies 48 of these objects have a literature counterpart. The new VIMOS data set is complementary to the many GC catalogues already present in the literature and it brings the total number of tracer particles around NGC 1399 to more than 1130 objects. With this comprehensive radial velocity sample, we have found that the velocity dispersion of the GC population (equally for red and blue GC populations) shows a relatively sharp increase from low velocity dispersion (similar to 250-350 km s(-1) ) to high velocity dispersion (similar to 300-4001cm s(-1) ) at projected radius of approximate to 10 arcmin (similar to 60 kpc) from the galaxy centre. This suggests that at a projected radius of approximate to 60 kpc both blue and red GC populations begin to be governed by the dominating Fornax cluster potential, rather than by the central NGC 1399 galaxy potential. This kinematic evidence corroborates similar results found using surface brightness analysis and planetary nebulae kinematics.
Symmetry Breaking of Frequency Comb in Varying Normal Dispersion Fiber Ring Cavity

We build on a previously reported frequency comb of mode spacing 0.136 nm in a fiber ring cavity of varying normal dispersion [1], to generate, for the first time, a frequency comb of mode spacing 0.144 nm centered at 978.544 nm to demonstrate the symmetry-breaking. By controlling the birefringence of the optical cavity through fiber stretching and polarization control, the spacing of the comb lines increases from 0.136 nm to 0.144 nm, and this small change in mode spacing generates very different spectral symmetry-breaking in the frequency comb relative to the frequency comb of mode spacing 0.136 nm. Interestingly, non-uniform depletion of primary modes is also observed. The experimental results are an important contribution in the continuing effort of understanding the dynamics of frequency combs involving large number of modes, nontrivial nonlinear waves and deterministic chaos.