Miracle-dz/UniFAR-FTUs huggingface dataset:
On the evolution of aspherical perturbations in the universe: An analytical model

I study the role of shear fields on the evolution of density perturbations by using an analytical approximate solution for the equations of motion of homogeneous ellipsoids embedded in a homogeneous background. The equations of motion of a homo- geneous ellipsoid (Icke 1973; White & Silk 1979 (hereafter WS)) are modified in order to take account of the tidal field as done in Watanabe 1993 and then are integrated ana- lytically, similarly to what done in WS. The comparison of the analytical solution with numerical simulations shows that it is a good approximation to the numerical one. This solution is used to study the evolution of the configuration of the ellipsoids, to calculate the evolution of the density contrast and that of the axial peculiar velocity of the ellip- soids for several values of the amplitude of the external tidal field, and compared again with numerical simulations. In order to calculate the evolution of the density contrast at turn-around and collapse velocity at the epoch of collapse, as a function of the ratio of the initial value of the semi-axes, I use the previously obtained approximate solution to modify the analytical model proposed by Barrow & Silk (1981) for the ellipsoids evolution in the non-linear regime. The density contrast at turn-around and the collapse velocity are found to be reduced with respect to that found by means of the spherical model. The reduction increases with increasing strength of the external tidal field and with increas- ing initial asymmetry of the ellipsoids. These last calculations are also compared with numerical solutions and they are again in good agreement with the numerical ones.
A multiwavelength study of the S 106 region II. Characteristics of the photon dominated region

The O star S 106 IR powers a bright, spatially extended 10 0 3 0 (1:75 0:5 pc at a distance of 600 pc) photon domi- nated region (PDR) traced by our observations of FIR fine structure lines and submm molecular transitions. The (C II) 158m, (C I) 609 and 370m, CO 7! 6, and CO 4! 3 measurements probe the large scale (1.2 pc) PDR emission, whereas (O I )6 3m, CN N = 3! 2, and CS J = 7! 6 observations are focused on the immediate (1 0 (0.2 pc)) environment of S 106 IR. A hot (T> 200 K) and dense (n> 3 10 5 cm 3 ) gas component (emission peaks of (C II) 158m, CO 7! 6, and CO 4! 3) is found at S 106 IR. Cooler gas associated with the bulk emission of the molecular cloud is characterized by two emission peaks (one close (20 00 east) to S 106 IR and one 120 00 to the west) seen in the (C I )a nd low-J (Jup 500 K), resulting in substantial population of the energetically higher 3 P2 state; the analysis of the mid- and high- J CO excitation con- firms the higher temperature at S 106 IR. At this position, the (O I )6 3m line is the most important cooling line, followed by other atomic FIR lines ((O III )5 2m, (C II) 158m) and high-J CO lines, which are more ecient coolants compared to (C I )2 ! 1a nd 1! 0. We compare the observed line ratios to plane-parallel PDR model predictions and obtain consistent re- sults for UV fluxes spanning a range from 10 2 to 10 3:5 G0 and densities around 10 5 cm 3 only at positions away from S 106 IR. Towards S 106 IR, we estimate a density of at least 3 10 5 at temperatures between 200 and 500 K from non-LTE modelling of the CO 16! 15/14! 13 ratio and the CO 7! 6 intensity. Our new observations support the picture drawn in the first part of this serie of papers that high-density ( n> 10 5 cm 3 ) clumps with a hot PDR surface are embedded in low- to medium density gas (n 10 4 cm 3 ).
Very long wavelength infrared type-II detectors operating at 80 K

We report a demonstration of very long wavelength infrared detectors based on InAs/GaSb superlattices operating at T=80 K. Detector structures with excellent material quality were grown on an optimized GaSb buffer layer on GaAs semi-insulating substrates. Photoconductive devices with 50% cutoff wavelength of λc=17 μm showed a peak responsivity of about 100 mA/W at T=80 K. Devices with 50% cutoff wavelengths up to λc=22 μm were demonstrated at this temperature. Good uniformity was obtained over large areas even for the devices with very long cutoff wavelengths.
High-frequency type II radio emissions associated with shocks driven by coronal mass ejections

We investigate the causal relationship between type II radio emissions in the frequency range from 1 to 14 MHz observed by the WAVES experiment on the Wind spacecraft and metric type II bursts observed by ground-based radio telescopes. We do this by extrapolating, to lower radio frequencies, fits to the frequency drift rates of metric type II bursts. These fits, which describe the shock propagation through the solar corona, are based on coronal density laws derived from white light observations. In order to establish whether the type II radio emissions were generated from the same shock, we explicitly chose events for which the type II radio emissions in the frequency range from 1 to 14 MHz were temporally separated from the associated metric type II bursts. The analyses indicate that some type II radio events observed by WAVES may not be low-frequency continuations of the apparently associated metric type II bursts. We conclude that two temporally separated shocks are required to account for the radio observations for these events, one shock being temporally well associated with the flare maximum. In two cases the observed GOES X-ray flux confirms the presence of two closely spaced solar events. We argue that the type II radio emissions observed by Wind/WAVES are likely generated by coronal mass ejection-driven shocks that form as low as 2 RS in the solar corona.
Saltating particles over flat beds

Measurements of ejection and impact velocities, trajectory lengths and maximum rise heights of sand grains (median diameters 118 and 188 μm) in saltation over a flat sand bed in a wind tunnel have been obtained from the digitization of multiple-image photo graphs. The mean angle of ejection is found to be about 30 o from the horizontal (rather than 90 o ) with mean vertical ejection velocity of about 2u * , where u * is the friction velocity. Trajectories of saltating grains have been computed, using the measurements of the initial ejection velocities and the mean velocity profile of the air flow.
Spatial self-organization in a multi-strain host–pathogen system

We develop stochastic spatial epidemic models with the competition of two pathogenic strains. The dynamics resulting from different approaches are examined using both non-spatial and spatially explicit models. Our results show that pair approximation, well-mixed ordinary differential equations (ODEs), Gillespie-algorithm-based simulations and spatially explicit models give similar qualitative results. In particular, the temporal evolution of the spatial model can be successfully approximated by pair equations. Simulation results obtained from the spatially explicit model show that, first, mutation plays a major role in multi-strain coexistence, second, mild virulence remarkably decreases the coexistence domain of the parameter space and, third, large-scale self-organized spatial patterns emerge for a wide range of transmission and virulence parameter values, where spatial self-organized clusters reveal a power law behavior within the coexistence domain.
Separation of small nonferrous particles using an inclined drum eddy-current separator with permanent magnets

This paper presents a method for separating small metallic nonferrous particles from two-component nonferrous mixtures using, a new type of dynamic eddy-current separator with permanent magnets. The so-called inclined drum eddy-current separator (IDECS) consists of an inclined vertical rotary drum covered with permanent magnets, alternately N-S and S-N oriented, directly fixed on the axis of an electric engine. The particles to be separated are brought into the field on an oblique trajectory, hit the drum, and are deflected in the variable field under electrodynamic and mechanical interactions. The strongly conducting and poorly conducting particles assume different trajectories depending on their electrical conductivities, which lead to their separation. The paper presents the results of grade and recovery of wastes consisting of small particles (under 5 mm) derived from Cu-Pb and Cu-Al mixtures. The advantages of IDECS are that its efficiency is close to that of the usual dynamic eddy-current separator and its equipment cost is lower. A disadvantage is that the intermediate product must be passed again through a separation process.
Design and fabrication of mechanochromic photonic crystals as strain sensor

A photonic crystal (PhC) is a periodic structure with periodicity comparable with the wavelength of light, having a photonic band gap in the visible range. In this contribution we discuss the possible use of PhCs as strain sensors, based on the observation that a distortion in the crystal structure produces a change in the reflected bandwidth. First, we demonstrate the feasible fabrication of a PhC having sub-micrometric polystyrene colloidal spheres in a PDMS matrix on a rubber substrate, and we demonstrate that the photonic properties change with substrate elongation according to theoretical prediction. The crystal sensitivity to strain depends directly on interplanar spacing and on Poisson’s ratio. To enhance the crystal strain resolution, we propose to fabricate inverse photonic crystals with FCC structure, which are known from the literature to exhibit a high negative Poisson's ratio. We carried out a theoretical investigation to predict the opto-mechanical response of inverse PhCs, and carried out preliminary tests to demonstrate their fabrication feasibility.
Micropropulsion Using a Laser Ablation Jet

We investigated exothermic laser ablation “fuels” for the micro Laser Plasma Thruster (µLPT), a novel type of microthruster. Using ms-duration laser pulses, which are required for multi-mode laser diodes to exceed ablation threshold fluence in the smallest focal spots available with conventional optics, successful target materials were restricted to those of low thermal conductivity, i.e., polymers, not metals. Polymers studied included carbon-doped polyvinylchloride for a passive target baseline, and several carbon-doped exothermic photopolymers specifically designed for their task, including polyvinylalcohol, a triazene polymer and a proprietary exothermic polymer (EP). In our single-shot impulse test setup, millimetric fuel samples were evaluated using a tiny torsion pendulum. Promising polymers were then made into fuel tapes and tested for continuous thrust under repetitive-pulse excitation. Two-layer fuel tapes consisted of a transparent supporting layer through which the light passed to ignite an absorbing fuel layer which formed a jet on the opposite side of the tape from that illuminated by the laser, an example of confined ablation. Best results were obtained with EP-1 up to 680 µN thrust with 2.1 W average optical power incident and jet velocity of 2‐3 km/s. Repeatability of our thrust-measuring torsion pendulum was improved to 1 µN.
THE ASYMPTOTIC EQUIPARTITION PROPERTY FOR ASYMPTOTIC CIRCULAR MARKOV CHAINS

In this article, we study the asymptotic equipartition property (AEP) for asymptotic circular Markov chains. First, the definition of an asymptotic circular Markov chain is introduced. Then by applying the limit property for the bivariate functions of nonhomogeneous Markov chains, the strong limit theorem on the frequencies of occurrence of states for asymptotic circular Markov chains is established. Next, the strong law of large numbers on the frequencies of occurrence of states for asymptotic circular Markov chains is obtained. Finally, we prove the AEP for asymptotic circular Markov chains.
Capillary wave analysis of rough solid-liquid interfaces in nickel

Crystal-liquid interfaces in nickel are investigated by molecular-dynamics computer simulations. Inhomogeneous systems of size Lx×Ly×Lz with Lz=5Ly are prepared where the crystal fcc phase at different orientations coexists with the liquid phase, separated by planar interfaces in the xy-plane. The lateral dimensions are varied, using two different geometries with Lx=Ly and with Ly≫Lx. In the framework of capillary wave theory (CWT), anisotropic interfacial stiffnesses and tensions are determined using different predictions of CWT with respect to the spectrum, finite-size broadening and different geometries. From a parameterization in terms of cubic harmonics up to 8th order, the anisotropic interfacial free energy is obtained.
Ordering of momentum transfer along VѵB in the AMPTE solar wind releases

As part of the active phase of the AMPTE mission, clouds of neutral lithium and barium were released into the solar wind from the German Ion Release Module (IRM). In all cases the clouds ionize significantly in the first few seconds following the release, such that the solar wind flow is deflected. A magnetic cavity (field zero) is formed, but this is not associated with a total exclusion of solar wind protons. The close (~35 km for lithium, ~100–200 km for barium) proximity of another spacecraft, the United Kingdom Subsatellite (UKS), allowed good data coverage of the local environment. In the events the minimum Larmor radii of the solar wind protons is of the order of the size of the interaction region of the release; that of "picked up" release ions being one (lithium) or two (barium) orders of magnitude larger, which indicate the need for a hybrid description in which the release ions respond as particles to the magnetic field structures, supported by a charge-neutralizing electron fluid. We highlight important results from the data which, while invalidating a description using MHD theory, are consistent with an ordering of the momentum transfer approximately along the local vѵB direction. We suggest that the existence of high proton flows in the interaction region requires a description which features at least two ion populations, and we show that this ordering may be predicted by treating the ions as a multifluid.
A Multisensor Observational Depiction of the Transition from Light to Heavy Rainfall on Subdaily Time Scales

Utilizing data from the Quick Scatterometer (QuikSCAT), a new observational parameter related to mesoscale cold pool activity [termed cold pool kinetic energy (CPKE)] is developed and investigated. CPKE and the Climate Prediction Center (CPC) morphing technique (CMORPH) rainfall product (both scaled to 2.258) are geolocated to 25 tropical island radiosonde sites. CPKE and radiosonde-derived nondilute CAPE, entraining CAPE (ECAPE), saturation fraction, and a new measure of convective inhibition (that takes into account stable layers above the LFC) are investigated with respect to rainfall time tendencies. Over the life cycle of rainfall, the composite temporal evolutions of CPKE and convective inhibition are quantitatively similar, but slightly out of phase. The maximum in CPKE precedes the maximum in convective inhibition by 3‐6h, thus allowing for an oscillation in the ratio of convective inhibition to CPKE relative to maximum rainfall. This ratio falls below unity at the time rainfall begins increasing and averages to near unity over the entire life cycle. These results imply a lagged, coupled relationship between CPKE and convective inhibition during rainfall. The rapid increase in rainfall occurs when saturation fraction and ECAPE exceed approximately 70% and 280Jkg 21 , respectively, consistent with previously noted thresholds for deep convection transition. However, since similar thermodynamic conditions are found before the increase in rainfall, observations support a hypothesis that the onset time for transition from light to heavy rainfall occurs when triggering energy (as captured in CPKE) approaches and exceeds convective inhibition. The observed onset and time scale for CAPE depletion by convection is nearly equivalent to the initial temporal appearance and time duration (6‐12h) that CPKE exceeds convective inhibition.
Theory on the mechanism of distal action of transcription factors: looping of DNA versus tracking along DNA

In this paper, we develop a theory on the mechanism of distal action of the transcription factors, which are bound at their respective cis-regulatory enhancer modules on the promoter-RNA polymerase II (PR) complexes to initiate the transcription event in eukaryotes. We consider both the looping and tracking modes of their distal communication and calculate the mean first passage time that is required for the distal interactions of the complex of enhancer and transcription factor with the PR via both these modes. We further investigate how this mean first passage time is dependent on the length of the DNA segment (L, base-pairs) that connects the cis-regulatory binding site and the respective promoter. When the radius of curvature of this connecting segment of DNA is R that was induced upon binding of the transcription factor at the cis-acting element and RNAPII at the promoter in cis-positions, our calculations indicate that the looping mode of distal action will dominate when L is such that L > 2πR and the tracking mode of distal action will be favored when L < 2πR. The time required for the distal action will be minimum when L = 2πR where the typical value of R for the binding of histones will be R ∼ 16 bps and L ∼ 102 bps. It seems that the free energy associated with the binding of the transcription factor with its cis-acting element and the distance of this cis-acting element from the corresponding promoter of the gene of interest is negatively correlated. Our results suggest that the looping and tracking modes of distal action are concurrently operating on the transcription activation and the physics that determines the timescales associated with the looping/tracking in the mechanism of action of these transcription factors on the initiation of the transcription event must put a selection pressure on the distribution of the distances of cis-regulatory modules from their respective promoters of the genes. The computational analysis of the upstream sequences of promoters of various genes in the human and mouse genomes for the presence of putative cis-regulatory elements for a set of known transcription factors using the position weight matrices available with the JASPAR database indicates the presence of cis-acting elements with maximum probability at a distance of ∼102 bps from the promoters which substantiates our theoretical predictions.
Why "C" armatures work (and why they don't!)

While plasma armatures perform well at high velocities, they have severe effects on railguns at the shot start position. Solid armatures overcome this factor but perform less well as velocities increase. Many types of solid armature have been tried, including metal fibers and magnetic obturator types, but the classic "C" type remains the armature of choice for high-velocity projectile launches. The recovery of fired armatures at the Kirkcudbright range has allowed many of these ideas to be formulated. This paper looks at what happens to "C" types, explains the basic processes occurring as the armature gains velocity, and identifies the limitations of this design. It offers suggestions for improving performance, including materials and design options, with outline results in some areas, and offers some design characteristics to be considered with this classic armature shape. Comparison with alternative armature concepts is briefly made so as to present an overall view.
Reliability estimation of generalized inverted exponential distribution

A generalized version of inverted exponential distribution (IED) is introduced in this paper. This lifetime distribution is capable of modelling various shapes of failure rates, and hence various shapes of ageing criteria. The model can be considered as another useful two-parameter generalization of the IED. Statistical and reliability properties of the generalized inverted exponential distribution are derived. Maximum likelihood estimation and least square estimation are used to evaluate the parameters and the reliability of the distribution. Properties of the estimates are also studied.
2-D MOSFET modeling including surface effects and impact ionization by self-consistent solution of the Boltzmann, Poisson, and hole-continuity equations

We present a new two-dimensional (2-D) MOSFET simulation method achieved by directly solving the Boltzmann transport equation for electrons, the hole-current continuity equation, and the Poisson equation self-consistently. The spherical harmonic method is used for the solution of the Boltzmann equation. The solution directly gives the electron distribution function, electrostatic potential, and the hole concentration for the entire 2-D MOSFET. Average quantities such as electron concentration and electron temperature are obtained directly from the integration of the distribution function. The collision integral is formulated to arbitrarily high spherical harmonic order, and new collision terms are included that incorporate effects of surface scattering and electron-hole pair recombination/generation. I-V characteristics, which agree with experiment, are calculated directly from the distribution function for an LDD submicron MOSFET. Electron-hole pair generation due to impact ionization is also included by direct application of the collision integral. The calculations are efficient enough for day-to-day engineering design on workstation-type computers.
DMSP/F2 electron observations of equatorward auroral boundaries and their relationship to magnetospheric electric fields

Energetic electron measurements from a particle detector on the DMSP/F2 satellite have been used to determine the corrected geomagnetic latitude ΛCGM of the equatorward boundary of the auroral oval. The satellite was launched into a nearly sun-synchronous, polar orbit centered on the 0700–1900 MLT meridian. Because of the wobble of the dipole and a very slow precessional motion of the orbit more than 6000 boundary crossings could be studied in the 1600–2300 and 0400–1000 MLT sectors. The detectors, which have large geometric factors, look radially away from the earth and detect precipitating electrons with energies between 50 eV and 20 keV. In the evening sector the equatorward boundaries are precisely determined from the rise in the total electron flux. The morningside boundary cannot always be clearly delineated. Data were divided into 1-hour magnetic local time bins with ∼400 samples per bin. In each of the MLT bins, ΛCGM was found to be linearly correlated to the KP index. Regression values of ΛCGM were projected to the magnetic equatorial plane by using the Mead-Fairfield magnetic field model. The projected boundaries are not in good agreement with the injection boundaries of Mauk and McIlwain (1974). They are best fit to boundaries derived by using Volland-Stern type electric fields with the axis of symmetry rotated into the evening sector for KP <2 and into the afternoon sector for KP ≥2.
Anisotropy-based performance analysis of linear discrete time invariant control systems

The anisotropic norm of a linear discrete-time-invariant system measures system output sensitivity to stationary Gaussian input disturbances of bounded mean anisotropy. Mean anisotropy characterizes the degree of predictability (or colouredness) and spatial non-roundness of the noise. The anisotropic norm falls between the H