Miracle-dz/UniFAR-FTUs huggingface dataset:
Ply-stacking effects on mechanical properties of Kevlar-29/banana woven mats reinforced epoxy hybrid composites

Development of new hybrid laminated composites of Kevlar-29 (K-29)/banana fiber (Musa acuminata) mats to meet future demand for fiber reinforced polymer (FRP) composites has been investigated. The different ply-stacking sequenced Kevlar (K)/natural (N) banana reinforced epoxy polymeric hybrid composite samples were designated as KN1, KN2, KN3, KN4, KN5 and KN6, in addition to NN7 and KK8 for single or non-hybrid FRP (control) composite samples. The ply-stacking effects on mechanical properties of all the laminated composite were investigated. The maximum tensile, flexural, impact and interlaminar shear strengths (ILSS) were obtained with sample KN4, because of the stacking of its Kevlar and natural banana mats, which was K2/N4/K2 of 8 layers and different from other stacking sequences. The percentage improvements on tensile strength of sample KN4 when compared with other hybrid composite samples KN1, KN2, KN3, KN5 and KN6 were 6.3, 4.4, 3.6, 13.1 and 11.3%, respectively. While, same optimum sample KN4 recorded highest flexural strength among hybrid samples with percentage improvements of 122.19, 70.97, 31.03 and 83.68% when compared with other hybrid samples KN2, KN3, KN5 and KN6, respectively. Similar trend of results was obtained for their tensile and flexural moduli. But, both hybrid composite samples KN3 and KN4 recorded higher impact strengths of 3.0 and 2.8 J, respectively, when compared with other hybrid counterparts. The tensile and flexural strengths of sample KN4 were 147.48 and 223.69 MPa, respectively. The tensile properties of various theoretical model were compared with experimental values.
Maximum Entropy Production and Non-Gaussian Climate Variability

Earth's atmosphere is in a state far from thermodynamic equilibrium. For example, the large scale equator-to-pole temperature gradient is maintained by tropical heating, polar cooling, and a midlatitude meridional eddy heat flux predominantly driven by baroclinically unstable weather systems. Based on basic thermodynamic principles, it can be shown that the meridional heat flux, in combination with the meridional temperature gradient, acts to maximize entropy production of the atmosphere. In fact, maximum entropy production (MEP) has been successfully used to explain the observed mean state of the atmosphere and other components of the climate system. However, one important feature of the large scale atmospheric circulation is its often non-Gaussian variability about the mean. This paper presents theoretical and observational evidence that some processes in the midlatitude atmosphere are significantly non-Gaussian to maximize entropy production. First, after introducing the basic theory, it is shown that the skewness of sea surface winds, damped by nonlinear surface drag, are consistent with the MEP principle. Then it is pointed out that the observed wavenumber spectrum of long planetary waves in the midlatitudes can be roughly explained by maximizing the meridional eddy heat flux (and related entropy production) of unstable baroclinic Eady waves. Finally observational evidence is presented that the meridional eddy heat flux is increased by non-Gaussian variability in meridional wind and temperatures anomalies.
DYNAMICAL BAR-MODE INSTABILITY IN DIFFERENTIALLY ROTATING MAGNETIZED NEUTRON STARS

This paper presents a numerical study over a wide parameter space of the likelihood of dynamical bar-mode instability in differentially rotating magnetized neutron stars. The innovative aspect of this study is the incorporation of magnetic fields in such a context, which have thus far been neglected in the purely hydrodynamical simulations available in the literature. The investigation uses the Cosmos++ code which allows us to perform three-dimensional simulations on a cylindrical grid at high resolution. A sample of Newtonian magnetohydrodynamical simulations starting from a set of models previously analyzed by other authors without magnetic fields has been performed, providing estimates of the effects of magnetic fields on the dynamical bar-mode deformation of rotating neutron stars. Overall, our results suggest that the effect of magnetic fields is not likely to be very significant in realistic configurations. Only in the most extreme cases are the magnetic fields able to suppress growth of the bar mode.
Angular dynamics of small crystals in viscous flows

The angular dynamics of a very small ellipsoidal particle in a viscous flow decouples from its translational dynamics, and the particle angular velocity is given by Jeffery's theory. It is known that cuboid particles share these properties. In the literature a special case is most frequently discussed, namely that of axisymmetric particles with a continuous rotation symmetry. Here we compute the angular dynamics of crystals that possess a discrete rotation symmetry and certain mirror symmetries, but that do not have a continuous rotation symmetry. We give examples of such particles that nevertheless obey Jeffery's theory. But there are other examples where the angular dynamics is determined by a more general equation of motion.
Interband coherence induced correction to adiabatic pumping in periodically driven systems

Periodic driving can create topological phases of matter absent in static systems. In terms of the displacement of the position expectation value of a time-evolving wavepacket in a closed system, a type of adiabatic dynamics in periodically driven systems is studied for general initial states possessing coherence between different Floquet bands. Under one symmetry assumption, the displacement of the wavepacket center over one adiabatic cycle is found to be comprised by two components independent of the time scale of the adiabatic cycle: a weighted integral of the Berry curvature summed over all Floquet bands, plus an interband coherence induced correction. The found correction is beyond a naive application of the quantum adiabatic theorem but survives in the adiabatic limit due to interband coherence. Our theoretical results are hence of general interest towards an improved understanding of the quantum adiabatic theorem. Our theory is checked using a periodically driven superlattice model with nontrivial topological phases. In addition to probing topological phase transitions, the adiabatic dynamics studied in this work is now also anticipated to be useful in manifesting coherence and decoherence effects in the representation of Floquet bands.
Elasto-capillary collapse of floating structures - Non-linear response of elastic structures under capillary forces

Flexible rings and rectangle structures floating at the surface of water are prone to deflect under the action of surface pressure induced by the addition of surfactant molecules on the bath. While the frames of rectangles bend inward or outward for any surface pressure difference, circles are only deformed by compression beyond a critical buckling load. However, compressed frames also undergo a secondary buckling instability leading to a rhoboidal shape. Following the pioneering works of \cite{Hu} and \cite{Zell}, we describe both experimentally and theoretically the different elasto-capillary deflection and buckling modes as a function of the material parameters. In particular we show how this original fluid structure interaction may be used to probe the adsorption of surfactant molecules at liquid interfaces.
A Study on the Influence of the Use of Sulphur Dioxide, the Distillation System and the Aging Conditions on the Final Sensory Characteristics of Brandy

Brandy is a unique alcoholic beverage obtained from wine distillates. Numerous studies have been published on its physicochemical traits and the effect of certain elaboration variables on them, but not many studies have been carried out from a sensory point of view or that have followed standardized methods applicable to this discipline. This study intends to determine the effect that certain production variables have on the sensory characteristics of brandy. These variables are the following: The use of sulphur dioxide during the fermentation of the base wine, the subsequent distillation system, the alcohol content during aging, the botanical origin of the aging casks, and their toasting degree. For this purpose, the guidelines provided by the ISO standards for sensory analysis have been followed, and chromatic parameters have also been determined. Heavy extractions from Quercus petraea casks resulted in brandies with widely varying colors, although these were hard to distinguish using the olfactory and gustatory properties associated with the factors under study. Conversely, those brandies aged in Quercus alba casks presented very consistent greenish shades that are not traditionally associated with aged brandy. This lower extraction could explain why the aromatic traits that are found in the fresh spirit are better preserved when this type of oak is used. The spirit obtained through the distillation of SO2-free wines aged in Quercus robur presented average sensory characteristics: Good color, smooth in the mouth, and medium-intensity oak notes. The distillates that were aged at 55% ABV were later perceived as more aromatically intense with a greater oak note on the palate. On the other hand, the brandies obtained from wines without SO2 added were perceived as less alcoholic, sweeter, and more balanced, with a softer oak note.
The SLUGGS survey: exploring the metallicity gradients of nearby early-type galaxies to large radii

Stellar metallicity gradients in the outer regions of galaxies are a critical tool for disentangling the contributions of in-situ and ex-situ formed stars. In the two-phase galaxy formation scenario, the initial gas collapse creates steep metallicity gradients, while the accretion of stars formed in satellites tends to flatten these gradients in the outskirts, particularly for massive galaxies. This work presents the first compilation of extended metallicity profiles over a wide range of galaxy mass. We use the DEIMOS spectrograph on the Keck telescope in multi-slit mode to obtain radial stellar metallicity profiles for 22 nearby early-type galaxies. From the calcium triplet lines in the near-infrared we measure the metallicity of the starlight up to 3 effective radii. We find a relation between the outer metallicity gradient and galaxy mass, in the sense that lower mass systems show steeper metallicity gradients than more massive galaxies. This result is consistent with a picture in which the ratio of ex-situ to in-situ formed stars is lower in less massive galaxies as a consequence of the smaller contribution by accretion. In addition, we infer a correlation between the strength of the calcium triplet feature in the near-infrared and the stellar initial mass function slope that is consistent with recent models in the literature.
Mg ii ABSORPTION CHARACTERISTICS OF A VOLUME-LIMITED SAMPLE OF GALAXIES AT z ∼ 0.1

We present an initial survey of Mg ii absorption characteristics in the halos of a carefully constructed, volume-limited subsample of galaxies embedded in the spectroscopic part of the Sloan Digital Sky Survey (SDSS). We observed quasars near sightlines to 20 low-redshift (z ∼ 0.1), luminous (Mr + 5log h ⩽−20.5) galaxies in SDSS DR4 and DR6 with the LRIS-B spectrograph on the Keck I telescope. The primary systematic criteria for the targeted galaxies are a redshift z ≳ 0.1 and the presence of an appropriate bright background quasar within a projected 75 h−1 kpc of its center, although we preferentially sample galaxies with lower impact parameters and slightly more star formation within this range. Of the observed systems, six exhibit strong (Weq(2796) ⩾ 0.3 Å) Mg ii absorption at the galaxy's redshift, six systems have upper limits which preclude strong Mg ii absorption, while the remaining observations rule out very strong (Weq(2796) ⩾ 1–2 Å) absorption. The absorbers fall at higher impact parameters than many non-absorber sightlines, indicating a covering fraction fc ≲ 0.4 for ⩾0.3 Å absorbers at z ∼ 0.1, even at impact parameters ⩽35 h−1 kpc (fc ∼ 0.25). The data are consistent with a possible dependence of covering fraction and/or absorption halo size on the environment or star-forming properties of the central galaxy.
A SAMPLE OF OB STARS THAT FORMED IN THE FIELD

We present a sample of 14 OB stars in the Small Magellanic Cloud that meet strong criteria for having formed under extremely sparse star-forming conditions in the field. These stars are a minimum of 28 pc in projection from other OB stars, and they are centered within symmetric, round H ii regions. They show no evidence of bow shocks, implying that the targets are not transverse runaway stars. Their radial velocities relative to local H i also indicate that they are not line-of-sight runaway stars. A friends-of-friends analysis shows that nine of the objects present a few low-mass companion stars, with typical mass ratios for the two highest-mass stars of around 0.1. This further substantiates that these OB stars formed in place, and that they can and do form in extremely sparse conditions. This poses strong constraints on theories of star formation and challenges proposed relations between cluster mass and maximum stellar mass.
Resonant properties of finite cracks and their acoustic emission spectra

In this paper, the acoustic emission accompanying the formation of brittle cracks of finite length is investigated theoretically using the approach based on the application of Huygens' principle for elastic solids. In the framework of this approach, the main input information required for calculations of acoustic emission spectra is the normal displacements of the crack edges as a function of frequency and wavenumber. Two simple approximate models defining this function are used in this paper for calculations of the acoustic emission spectra and directivity functions of a crack of finite length. The simplest model considers a crack that opens monotonously to its static value. The more refined model accounts for oscillations during crack opening and considers a crack of finite size as a resonator for symmetric modes of Rayleigh waves propagating along the crack edges and partly reflecting from the crack tips. Analytical solutions for generated acoustic emission spectra are obtained for both models and compared with each other. It is shown that resonant properties of a crack are responsible for the appearance of noticeable peaks in the frequency spectra of generated acoustic emission signals that can be used for evaluation of crack sizes. The obtained analytical results are illustrated by numerical calculations.
Associations of sleep and emotion regulation processes in childhood and adolescence - a systematic review, report of methodological challenges and future directions

Sleep and emotions are closely associated; however, the methodological challenges in the examination of sleep and the processes of emotion regulation in children and adolescents have not been investigated so far. Additionally, there is the demand to identify the levels of emotion regulating processes in which problematic or restricted sleep causes effect. Experimental sleep deprivation as well as prevalent sleep problems have been found to have negative influence on mental health and regulating functions. This review focuses first on the methodological protocols of the included studies. Subsequently, the results are summarized in the context of a multilevel model of emotion regulation. Thereafter, suggestions for future directions are given. Sleep problems and sleep deprivation are associated with a decrease of functional emotion regulating behavior and impaired emotion generation, and prolonged sleep enhances better mood and affect states, positive emotion expression, and faster sensory processing in response to emotional stimuli. This literature review highlights the limitations in current research, focusing on types of measurements, task characteristics, and data analysis. At the conclusion, suggestions are given for the future research direction in the field of sleep and emotion regulation in children and adolescents.
NGC 5548: LACK OF A BROAD Fe Kα LINE AND CONSTRAINTS ON THE LOCATION OF THE HARD X-RAY SOURCE

We present an analysis of the co-added and individual 0.7–40 keV spectra from seven Suzaku observations of the Sy 1.5 galaxy NGC 5548 taken over a period of eight weeks. We conclude that the source has a moderately ionized, three-zone warm absorber, a power-law continuum, and exhibits contributions from cold, distant reflection. Relativistic reflection signatures are not significantly detected in the co-added data, and we place an upper limit on the equivalent width of a relativistically broad Fe Kα line at EW ⩽ 26 eV at 90% confidence. Thus NGC 5548 can be labeled as a “weak” type 1 active galactic nucleus (AGN) in terms of its observed inner disk reflection signatures, in contrast to sources with very broad, strong iron lines such as MCG–6-30-15, which are likely much fewer in number. We compare physical properties of NGC 5548 and MCG–6-30-15 that might explain this difference in their reflection properties. Though there is some evidence that NGC 5548 may harbor a truncated inner accretion disk, this evidence is inconclusive, so we also consider light bending of the hard X-ray continuum emission in order to explain the lack of relativistic reflection in our observation. If the absence of a broad Fe Kα line is interpreted in the light-bending context, we conclude that the source of the hard X-ray continuum lies at radii rs ≳ 100 rg. We note, however, that light-bending models must be expanded to include a broader range of physical parameter space in order to adequately explain the spectral and timing properties of average AGNs, rather than just those with strong, broad iron lines.
New perspective on galaxy clustering as a cosmological probe: General relativistic effects

We present a general relativistic description of galaxy clustering in a Friedmann-Lemaitre-Robertson-Walker universe. The observed redshift and position of galaxies are affected by the matter fluctuations and the gravity waves between the source galaxies and the observer, and the volume element constructed by using the observables differs from the physical volume occupied by the observed galaxies. Therefore, the observed galaxy fluctuation field contains additional contributions arising from the distortion in observable quantities and these include tensor contributions as well as numerous scalar contributions. We generalize the linear bias approximation to relate the observed galaxy fluctuation field to the underlying matter distribution in a gauge-invariant way. Our full formalism is essential for the consistency of theoretical predictions. As our first application, we compute the angular auto correlation of large-scale structure and its cross correlation with CMB temperature anisotropies. We comment on the possibility of detecting primordial gravity waves using galaxy clustering and discuss further applications of our formalism.
MILLIMETER RADIO CONTINUUM EMISSIONS AS THE ACTIVITY OF SUPERMASSIVE BLACK HOLES IN NEARBY EARLY-TYPE GALAXIES AND LOW-LUMINOSITY ACTIVE GALACTIC NUCLEI

We conducted millimeter continuum observations for samples of nearby early-type galaxies (21 sources) and nearby low-luminosity active galactic nuclei (LLAGNs; 16 sources) at 100 GHz (λ3 mm) using the Nobeyama Millimeter Array (NMA). In addition, we performed quasi-simultaneous observations at 150 GHz (λ2 mm) and 100 GHz for five LLAGNs. Compact nuclear emissions showing flat or inverted spectra at centimeter-to-millimeter wavelengths were found in many LLAGNs and several early-type galaxies. Moreover, significant flux variability was detected in three LLAGNs. These radio properties are similar to Sgr A*. The observed radio luminosities are consistent with the fundamental plane of black hole activity that was suggested on the basis of samples with black hole masses ranging from 10 to 1010 M☉. This implies nuclear jets powered by radiatively inefficient accretion flows onto black holes.
DISK-OUTFLOW COUPLING: ENERGETICS AROUND SPINNING BLACK HOLES

The mechanism by which outflows and plausible jets are driven from black hole systems still remains observationally elusive. This notwithstanding, several observational evidences and deeper theoretical insights reveal that accretion and outflow/jet are strongly correlated. We model an advective disk-outflow coupled dynamics, incorporating explicitly the vertical flux. Inter-connecting dynamics of outflow and accretion essentially upholds the conservation laws. We investigate the properties of the disk-outflow surface and its strong dependence on the rotation parameter of the black hole. The energetics of the disk outflow strongly depend on the mass, accretion rate, and spin of the black holes. The model clearly shows that the outflow power extracted from the disk increases strongly with the spin of the black hole, inferring that the power of the observed astrophysical jets has a proportional correspondence with the spin of the central object. In the case of blazars (BL Lacs and flat spectrum radio quasars, FSRQs), most of their emission are believed to be originated from their jets. It is observed that BL Lacs are relatively low luminous than FSRQs. The luminosity might be linked to the power of the jet, which in turn reflects that the nuclear regions of the BL Lac objects have a relatively low spinning black hole compared to that in the case of FSRQs. If extreme gravity is the source that powers strong outflows and jets, then the spin of the black hole, perhaps, might be the fundamental parameter to account for the observed astrophysical processes in an accretion powered system.
First stars - XIII. Two extremely metal-poor RR Lyrae stars

Context. The chemical composition of extremely metal-poor stars (EMP stars; [Fe/H] < ∼− 3) is a unique tracer of early nucleosynthesis in the Galaxy. As such stars are rare, we wish to find classes of luminous stars which can be studied at high spectral resolution. Aims. We aim to determine the detailed chemical composition of the two EMP stars CS 30317-056 and CS 22881-039, originally thought to be red horizontal-branch (RHB) stars, and compare it to earlier results for EMP stars as well as to nucleosynthesis yields from various supernova (SN) models. In the analysis, we discovered that our targets are in fact the two most metal-poor RR Lyrae stars known. Methods. Our detailed abundance analysis, taking into account the variability of the stars, is based on VLT/UVES spectra (R � 43 000) and 1D LTE OSMARCS model atmospheres and synthetic spectra. For comparison with SN models we also estimate NLTE corrections for a number of elements. Results. We derive LTE abundances for the 16 elements O, Na, Mg, Al, Si, S, Ca, Sc, Ti, Cr, Mn, Fe, Co, Ni, Sr and Ba, in good agreement with earlier values for EMP dwarf, giant and RHB stars. Li and C are not detected in either star. NLTE abundance corrections are newly calculated for O and Mg and taken from the literature for other elements. The resulting abundance pattern is best matched by model yields for supernova explosions with high energy and/or significant asphericity effects. Conclusions. Our results indicate that, except for Li and C, the surface composition of EMP RR Lyr stars is not significantly affected by mass loss, mixing or diffusion processes; hence, EMP RR Lyr stars should also be useful tracers of the chemical evolution of the early Galactic halo. The observed abundance ratios indicate that these stars were born from an ISM polluted by energetic, massive (25−40 M� )a nd/or aspherical supernovae, but the NLTE corrections for Sc and certain other elements do play a role in the choice of model.