Miracle-dz/UniFAR-FTUs huggingface dataset:
Hot Holographic Giant Loop

We consider the Polyakov loop operator in finite temperature planar N = 4 supersymmetric Yang-Mills theory defined on a spatial S3 and in representations where the number of boxes in the Young Tableau k is large and scales so that kN remains finite in the large N limit. We review the argument that, in the de-confined phase of the gauge theory, and for symmetric representations with row Young tableau, there is a quantum phase transition in the expectation value of the Polyakov loop operator which occurs as the size of the representation is increased beyond a critical value of kN. We also argue that for completely antisymmetric representations with column tableau, there is no such phase transition. The AdS/CFT dual of such large representation loops are thought to be probe D-branes with k units of fundamental string charge dissolved in their world-volumes. Our results for both symmetric and antisymmetric representations are consistent with what is known about these branes on the thermal AdS black hole background.
Possible calorimetric effects at mercury due to solar wind‐magnetosphere interactions

As a result of the solar wind interaction with the magnetosphere of Mercury, we expect several effects which may be observable with ground-based and/or near-earth radio and infrared telescopes: (1) there may be direct interaction of the solar wind with the surface of Mercury which could produce measurable heating effects; (2) substormlike magnetotail processes within Mercury's magnetosphere may precipitate particles carrying from 1010 to 1012 W (or more) of power into narrow latitudinal bands on the cold (≲ 130 K) darkside of Mercury, producing surface-heated “auroral” zones; and (3) the presence of Jovian electrons within the inner Hermean magnetosphere may produce transient, very low frequency synchrotron-emitting radiation belts. Hence remote radio and infrared observations hold substantial promise for providing information about the intrinsic properties of Mercury's magnetic field, about the planetary surface, and about the dynamical interaction of the Hermean magnetosphere with the solar wind at ∼0.4 AU.
Fuzzy Categorization of Weather Conditions for Thermal Mapping

Thermal mapping is a technique that uses a vehicle-mounted infrared radiometer to measure the variation of road surface temperature (RST). Conventionally, the technique is conducted under three qualitatively categorized weather conditions: extreme, intermediate, and damped. These three categories represent basic weather patterns and are widely used in thermal mapping. In real-time operation, however, determination of the weather category is hampered by the lack of systematic classification. Furthermore, certain skills and knowledge of both thermal mapping and meteorology are required. As the thermal mapping technique develops in the direction of providing a platform for automatic and dynamic forecasting of RST over an entire road network, it is necessary to have some kind of hands-off, quantitative, systematic, accurate, and fast categorization of weather conditions for thermal mapping. For this purpose, the relationship between the change of weather conditions and variation of RST was analyzed to define a time domain for application of a reliable categorization algorithm. Fuzzy membership functions were then established, based on cloud amount, cloud type, wind speed, and relative humidity, to compose a fuzzy function of weather categorization for thermal mapping. The results of validation for the fuzzy categorization show that the algorithm can become a useful tool for thermal mapping.
Exploring symmetry plane conditions in numerical Euler solutions

The motion of the position of the maximum of vortic- ity kk∞ and growth of enstrophy are explored numerically using a recent calculation at moderately high resolution. We provide an ex- act analytic formula for the motion of kk∞ in the symmetry plane and use it to validate the numerical data. This motion drifts with respect to the local Lagrangian frame of reference due to the local gradient of vortex stretching, and can thus be associated with de- pletion of the circulation in the symmetry plane from the vicinity of kk∞. Despite this depletion, the numerical data is consistent with singular growth of the 3D enstrophy and symmetry-plane enstro- phy that is bounded by inequalities analogous to the type known for the three-dimensional Navier-Stokes equations, using their re- spective enstrophies and with the viscosity being replaced by the circulation invariant.
Inertial collapse of liquid rings

Abstract Liquid rings can be generated in the Leidenfrost state using liquid oxygen of low boiling point ( $- 183~\textdegree \mathrm{C} $ ) and high magnetic susceptibility, allowing one to ‘sculpt’ the liquid into a ring shape using an annular magnet. When the magnetic field is turned off, the ring shrinks back into a puddle with a constant acceleration. A potential flow approach accurately describes the dynamics of closure with an equation reminiscent of the Rayleigh–Plesset equation for the collapse of transient cavities.
Tropical Cyclone Convection and Intensity Analysis Using Differenced Infrared and Water Vapor Imagery

Abstract A technique to identify and quantify intense convection in tropical cyclones (TCs) using bispectral, geostationary satellite imagery is explored. This technique involves differencing the water vapor (WV) and infrared window (IRW) channel brightness temperature values, which are available on all current operational geostationary weather satellites. Both the derived IRW minus WV (IRWV) imagery and the raw data values can be used in a variety of methods to provide TC forecasters with important information about current and future intensity trends, a component within the operational TC forecasting arena that has shown little improvement during the past few decades. In this paper several possible uses for this bispectral technique, both qualitative and quantitative, are explored and outlined. Qualitative monitoring of intense convection can be used as a proxy for passive microwave (MW) imager data obtained from polar-orbiting satellite platforms when not available. In addition, the derived imagery may.
Positively invariant sets for singular discrete-time systems

Abstract The aim of this paper is to present some results allowing positively invariant and asymptotically stable polyhedral sets to be determined for the linear singular discrete-time system ExK+1 = AxK; the regular and singular cases of pencil (E, A) are considered. Necessary and sufficient algebraic conditions guaranteeing that some sets are positively invariant and asymptotically stable are given. Also discussed are some issues relating to the positive invariance of some domains and consistent initial conditions. Finally, as an application, the proposed results are used to determine a stability domain for a state feedback regulator with constraints on controls
Aeolian tones radiated from flow past two square cylinders in tandem

The sound generated by two square cylinders placed in a tandem arrangement in a uniform flow at low Mach numbers is studied by direct solution of the two-dimensional unsteady compressible Navier-Stokes equations. Special attention is paid to the effect of the spacing between the two cylinders on the generation mechanism of the sound. Results show that the magnitude of the generated sound varies drastically depending on the spacing. When the spacing is small, roll-up of the shear layer separated from the upstream cylinder is suppressed and the sound generation is also suppressed; near a critical value of the spacing, the magnitude of the generated sound is about 10−2 as small as that generated by a single square cylinder. With increased spacing beyond a critical value, the shear layer separated from the upstream cylinder rolls up to form vortices in front of the downstream cylinder; the rolled-up vortices interact with the downstream cylinder, leading to a drastic increase in the magnitude of the generated.
Magnetic field distribution in spiral galaxies.

On discute de la distribution spatiale des champs magnetiques a grande echelle dans les disques gazeux des galaxies spirales. On compare les resultats des calculs aux observations des champs magnetiques dans la galaxie, M 31, IC 342 et M 81. On note un accord general avec la theorie dynamo
Supernova constraints on brane world dark energy

Braneworld models of dark energy are examined in the light of observations of high redshift type Ia supernovae. Braneworld models admit several novel and even exotic possibilities which include: (i) The effective equation of state of dark energy can be more negative than in LCDM: $w \leq -1$; (ii) A class of braneworld models can encounter a `quiescent' future singularity at which the energy density and the Hubble parameter remain well behaved, but higher derivatives of the expansion factor ($\stackrel{.}{a}$, $\stackrel{.}{a}$ etc.) diverge when the future singularity is reached; (iii) The current acceleration of the universe is a {\em transient feature} in a class of models in which dark energy `disappears' after a certain time, giving rise to a matter dominated universe in the future. Since horizons are absent in such a space-time, a braneworld model with {\em transient acceleration} might help reconcile current supernova-based observations of an accelerating universe with the demands of string/M-theory. A maximum likelihood analysis reveals that braneworld models satisfy the stringent demands imposed by high redshift supernovae and a large region in parameter space agrees marginally better with current observations than LCDM. For instance, models with $w -1)$ provide better agreement with data than LCDM for $\Omega_m \ggeq 0.3 (\lleq 0.25)$.
Interaction Topologies and Information Flow

Networks are ubiquitous, underlying systems as diverse as the Internet, food webs, societal interactions, the cell, and the brain. Of crucial importance is the coupling of network structure with system dynamics, and much recent attention has focused on how information, such as pathogens, mutations, or ideas, flow through networks. In this dissertation, we advance the understanding of how network structure affects information flow in two important classes of models. The first is an independent interaction model, which is used to investigate the propagation of advantageous alleles in evolutionary algorithms. The second is a threshold model, which is used to study the dissemination of ideas, fads, and innovations throughout populations. This journal-format dissertation comprises three interrelated studies, in which we investigate the influence of network structure on the dynamical properties of information flow. In the first study, we develop an analytical technique to approximate system dynamics in arbitrarily structured regular interaction topologies. In the second study, we investigate the flow of advantageous alleles in degree-correlated scale-free population structures, and provide a simple topological metric for assessing the selective pressures induced by these networks. In the third study, we characterize the conditions in which global information cascades occur in threshold models of binary decisions with externalities, structured on degree-correlated Poisson-distributed random networks.
EMIC waves growth and guiding in the presence of cold plasma density irregularities

Intense electromagnetic ion cyclotron (EMIC) waves are observed within plasmaspheric plumes during geomagnetic storms and are believed to be a significant driver of loss of both ring current protons and radiation belt electrons. In this study, we use ray tracing together with path‐integrated linear growth calculations to analyze the amplification and propagation of EMIC waves within cold plasma density irregularities characteristic of the plasmaspheric plume. All waves are launched at the equator in the range of L = 5 to 7, and wave amplification is analyzed as a function of frequency and initial wave normal angle. These results are compared to a baseline case without irregularities, which show that guiding is possible for irregularity sizes on the order of the EMIC wavelength. Results suggest that typical structures with density levels above and below the average value can result in both areas of increased as well as suppressed wave activity.
Nonhomologous contraction and equilibria of self-gravitating, magnetic interstellar clouds embedded in an intercloud medium: star formation. II. Results.

We present models representing the nonhomologous contraction and equilibria of isothermal, self-gravitating interstellar clouds bounded by the pressure of a hot and tenuous intercloud medium. A frozen-in interstellar magnetic field threads both media. It invariably causes a self-gravitating cloud to become oblate with its major axis normal to the field lines. The flattening increases with the strength of the magnetic field, or with stronger gravitational forces, or with increasing intercloud pressure: other quantities remainig fixed in each case. A ratio of gas densities at the center and at the surface exceeding the Bonor-Ebert critical value (=14.3) can easily be obtained while the cloud is still at equilibrium. For a fixed mass-to-flux ratio, an increasing intercloud pressure eventually leads to gravitational collapse. A cloud of uniform density threaded by a uniform magnetic field and surrounded by an intercloud medium of fixed pressure can reach equilibrium only if its radius does not exceed a critical value; otherwise collapse ensues.We determine the slope kappa of the (log B, log p)-curve at the center of a cloud. It is certainly less than its isotropic-contraction value (2/3) with a likely range 1/3< or =kappa< or =1/2. (No theoretical lower limit exists; it must be setmore » by observations.) This implies that milligauss fields can be found only in regions of gas density approximately-greater-than10/sup 6/ cm/sup -3/, unlike current notions of 10/sup 4.5/ cm/sup -3/. Finally, we show that neither an O5 star nor a supernova explosion can disperse a dense, massive cloud. Hence, the observed inefficiency of the star formation process must have other causes. We suggest the magnetic field as such a cause; it may hold the collapse of the outlying portions of a cloud. This necessitates a sequence of events leading to star formation qualitatively different from current ideas. (AIP)« less
The formation of current sheets in the solar atmosphere

A simple model of the effect of slow photospheric motions on the coronal magnetic field is examined. In this model, a magnetic field is stretched between two conducting plates and slow tangential displacements of the plates cause the field to evolve quasi-statically. If the field is treated as a continuum, the interior magnetic topology is uniquely specified by the displacement of the boundaries, while the topology of a field made up of discrete flux tubes is not determined by the boundary displacement. Treating the field as a continuum, it is found that small perturbations of a constant vertical or weakly sheared field can come to an equilibrium free of singularities if the separation between the plates is finite. 34 references.
Analysis of ferroelectric polarization switching in (NH4)0.39K0.61NO3 films using nucleation limited switching model

The polarization switching transients of spray deposited ferroelectric (NH4)0.39K0. 61NO3 (NKN) films has been analyzed with nucleation limited switching (NLS) model by considering domain growth limited process. The experimentally measured microscopic polarization switching curves fitted well with NLS model and the characteristic switching times obeyed the Lorentzian distribution function. The local field variation was found to be minimum at pulse amplitude 15 V, which makes the polarization reversal more probable. The value of spontaneous polarization, Ps and coercive field, Ec was found to be 6.58 μC/cm2 and 4.10 kV/cm, respectively. The value of Ps from the switching and P-E loop is in good agreement with each other. The field emission scanning electron microscopy and atomic force microscopy images of the NKN film reveal the formation of nanoparticles of NKN.The polarization switching transients of spray deposited ferroelectric (NH4)0.39K0. 61NO3 (NKN) films has been analyzed with nucleation limited switching (NLS) model by considering domain growth limited process. The experimentally measured microscopic polarization switching curves fitted well with NLS model and the characteristic switching times obeyed the Lorentzian distribution function. The local field variation was found to be minimum at pulse amplitude 15 V, which makes the polarization reversal more probable. The value of spontaneous polarization, Ps and coercive field, Ec was found to be 6.58 μC/cm2 and 4.10 kV/cm, respectively. The value of Ps from the switching and P-E loop is in good agreement with each other. The field emission scanning electron microscopy and atomic force microscopy images of the NKN film reveal the formation of nanoparticles of NKN.
Investigation of 131 Herbig Ae/Be Candidate Stars

We present a new catalog of 108 Herbig Ae/Be candidate stars identified in the Pico dos Dias Survey, together with 19 previously known candidates and four objects selected from the IRAS Faint Source Catalog. These 131 stars were observed with low- and/or medium-resolution spectroscopy, and we complement these data with high-resolution spectra of 39 stars. The objects present a great variety of Hα line profiles and were separated according to them. Our study suggests that most of the time a Herbig Ae/Be star will present a double peak Hα line profile. Correlations among different physical parameters, such as spectral type and v sin i with Hα line profiles were searched. We found no correlation among Hα line profiles and spectral type or v sin i except for stars with P Cygni profiles, where there is a correlation with v sin i. We also use preliminary spectral energy distributions to seek for any influence of the circumstellar medium in the Hα line profiles. The presence of [O I] and [S II] forbidden lines is used together with the Hα line profiles and these preliminary spectral energy distributions to discuss the circumstellar environment of the Herbig Ae/Be candidates. The distribution of the detected [O I] and [S II] forbidden lines among different spectral types points to a significantly higher occurrence of these lines among B stars, whereas the distribution among different Hα profile types indicates that forbidden lines are evenly distributed among each Hα line-profile type. Combining the distance estimates of the Herbig candidates with the knowledge of the interstellar medium distribution, we have found that 84 candidates can be associated with some of the more conspicuous SFRs, being in the right direction and at a compatible distance. As a further means of checking the properties of the HAeBe candidates, as well as their present evolutionary status, the derived luminosities and effective temperatures of the stars with possible association to the star-forming regions and/or Hipparcos distances were plotted together with a set of pre–main-sequence evolutionary tracks on an HR diagram. A set of 14 stars were found out of their expected positions in the HR diagram.
Cosmic Reionization after Planck: The Derived Growth of the Ionizing Background now matches the Growth of the Galaxy UV Luminosity Density

Thomson optical depth measurements from Planck provide new insights into the reionization of the universe. To obtain new model-independent constraints on the properties of the ionizing sources, we determine the empirical evolution of the ionising background. We use a simple two-parameter model to map out the evolution in this background at z>~6 from the new Planck optical depth tau measurements and from the constraints provided by quasar absorption spectra and the prevalence of Ly-alpha emission in z~7-8 galaxies. We find the redshift evolution in the ionising background N_{ion} required by the observations to be dlog_{10} N_{ion}/dz(z=8)=-0. 19_{-0.11}^{+0.09}, largely independent of the assumed clumping factor C_{HII} and entirely independent of the identity of the ionizing sources. The trend in N_{ion} is well-matched by the evolution of the galaxy UV-luminosity density (dlog_{10} rho_{UV}/dz=-0.11+/-0.04) to a magnitude limit >~-13 mag, suggesting that galaxies are the sources that drive the reionization of the universe. The role of galaxies is further strengthened by the conversion from the UV luminosity density to N_{ion}(z) being possible for physically plausible values of the escape fraction f_{esc}, the Lyman-continuum photon production efficiency xi_{ion}, and faint-end cut-off M_{lim} to the LF. Lastly, we use the inferred evolution in the ionizing background to estimate the z~10 UV luminosity density, finding this luminosity density to be 12_{-7}^{+21}x lower than at z~6, consistent with current measurements at z~10. Quasars/AGN appear to match neither the redshift evolution nor normalization of the ionizing background. This new approach of contrasting the inferred evolution of the ionising background with that of the galaxy UV luminosity density adds to the growing observational evidence that galaxies are the sources that drive the reionization of the universe.
Global Fields of Soil Moisture and Land Surface Evapotranspiration Derived from Observed Precipitation and Surface Air Temperature.

Abstract The global fields of normal monthly soil moisture and land surface evapotranspiration are derived with a simple water budget model that has precipitation and potential evapotranspiration as inputs. The precipitation is observed and the potential evapotranspiration is derived from the observed surface air temperature with the empirical regression equation of Thornthwaite. It is shown that at locations where the net surface radiation flux has been measured, the potential evapotranspiration given by the Thornthwaite equation is in good agreement with those obtained with the radiation-based formulations of Priestley and Taylor, Penman, and Budyko, and this provides the justification for the use of the Thornthwaite equation. After deriving the global fields of soil moisture and evapotranspiration, the assumption is made that the potential evapotranspiration given by the Thornthwaite equation and by the PriestleyTaylor equation will everywhere be about the same; and the inverse of the PriestleyTaylor.
Fabrication and characterization of a nanoelectromechanical switch with 15-nm-thick suspension air gap

We developed titanium nitride (TiN) based nanoelectromechanical (NEM) switch with the smallest suspension air-gap thickness ever made to date by a “top-down” complementary metal-oxide semiconductor fabrication methods. Cantilever-type NEM switch with a 15-nm-thick suspension air gap and a 35-nm-thick TiN beam was successfully fabricated and characterized. The fabricated cantilever-type NEM switch showed an essentially zero off current, an abrupt switching with less than 3mV/decade, and an on/off current ratio exceeding 105 in air ambient. Also achieved was an endurance of over several hundreds of switching cycles under dc and ac biases in air ambient.