Miracle-dz/UniFAR-FTUs huggingface dataset:
A comprehensive model of ion diffusion and charge exchange in the cold io torus

An analytic model of lossy radial diffusion of ions in the cold Io torus is developed. The model includes ion-neutral charge exchange reactions with extended atomic and molecular clouds of S, O, SO, and SO{sub 2} which act as combined sources/sinks of ions that couple the species and their various charge states. The ion-molecule reactions are crucial to the analysis; in particular, the exothermic reaction S{sup +} + SO {r arrow} S + SO{sup +} followed by rapid dissociative recombination for the resultant SO{sup +} ion is the only viable way of removing S{sup +} form the cold torus in order that its density conform with the many independent measurements of it. Model calculations indicate optimum values for the neutral densities are (S) = 7 cm{sup {minus}3}, (O) = 30 cm{sup {minus}3}, (SO) = 10 cm{sup {minus}3}, and (SO{sub 2}) = 20 cm{sup {minus}3}. Such a neutral cloud environment yields an excellent correspondence of hot torus ion partitioning models with that of the cold torus through lossy radial diffusion. The preferred model of the analysis for the hot torus composition is (S{sup +}) = 220 cm{sup {minus}3}, (S{sup 2+}) = 340 cm{sup {minus}3}, (S{sup 3+}) = 40 cm{sup {minus}3}, (O{supmore » +}) = 800 cm{sup {minus}3}, and (O{sup 2+}) = 90 cm{sup {minus}3} at Voyager 1 epoch. These numbers imply not only that the plasma torus is SO{sub 2}-based but also that dissociation of the molecular SO{sub 2} cloud is the primary source of all other neutrals that are distributed throughout the Io torus region. A unique feature of the model is the production of a boundary layer between the ocld and hot tori where cold S{sup +} ions mix with hot plasma torus ions in a manner that reproduces the ribbonlike plasma structure described by Trauger (1984). « less
Multi-access fading channels: delay-limited capacities

We consider the multi-access, white-noise, fading channel, and introduce a notion of delay-limited capacity, which is the maximum rate achievable with delay independent of how slow the fading is. We characterize the delay-limited capacity region and the associated optimal power allocation schemes. We show that successive decoding is optimal, and the optimal decoding order and power allocation can be found explicitly as a function of the fading states; this is a consequence of an underlying polymatroid structure that we exploit.
A sample of galaxies near the South Celestial Pole

This paper reports the results of a modest redshift survey carried out, at generally low Galactic latitudes, in the vicinity of the South Celestial Pole. Target galaxies were selected as a ‘representative’ sample of underlying large-scale structures. Dimensions, approximate magnitudes and radial velocity measurements, are reported for 336 galaxies. Two obvious Seyfert 1 galaxies, one probably Seyfert 1 and three Seyfert 2 galaxies have been discovered. The redshifts are used to supplement existing data and serve to map southern voids and features out to 25 000 km s −1 in the region 270 ◦ b > −45 ◦ . Three distinct superclusters and twenty apparent voids are tentatively identified. One Void, at l = 300 ◦ , b =− 20 ◦ , cz = 16 000 km s −1 , with a diameter of 6000 km s −1 , is as large as any yet mapped. It appears as part of a general underdense region.
Adaptive algorithms for tracking roots of spectral polynomials

The authors propose two fast adaptive algorithms, namely Newton's gradient algorithm and the modified Rayleigh-quotient adaptive algorithm. These methods work in association with adaptive eigensubspace algorithms for tracking the zeros of a nonstationary spectrum polynomial. Newton's gradient algorithm is developed under a linearly constrained minimization procedure, whereas the modified Rayleigh-quotient adaptive technique is derived from the Rayleigh-quotient calculating procedure for the eigenstructure of the companion matrix of the spectrum polynomial. For an Nth-order polynomial, the adaptive algorithm has requires computational complexity O(N). The adaptive algorithms operate independently for each zero and have better tracking and computational complexity than the direct rooting method or the zero-sensitive adaptive algorithm. <<ETX>>
A bound on X-ray emission from the intrasupercluster medium

The Bahcall-Soneira (1984) complete sample of superclusters was searched for X-ray emission in the HEAO 1 A-2 data base. No statistically significant emission from diffuse intrasupercluster gas was detected; a 3-sigma upper limit to the mean individual flux is 10 to the -11th ergs/sq cm per s. Implications of this bound to measurements of the Zeldovich-Sunyaev (1969) effect toward clusters within a supercluster and to the supercluster contribution to the cosmic X-ray background are discussed. 24 references.
Interrelation between Papkovich–Neuber and Stokes general solutions of the stokes equations in spheroidal geometry

Many practical applications involve particles (inorganic, organic, biological) with non-spherical but still axisymmetric shapes. The present work is concerned with some interesting aspects of the theoretical analysis of Stokes flow in spheroidal domains. Two different complete representations of Stokes flow are considered here. The first one is obtained through the theory of generalized eigenfunctions, according to which the stream function is expanded in terms of separable and semiseparable eigenfunctions. The second one, valid in non-axisymmetric geometries as well, is the Papkovich-Neuber differential representation, where the velocity and pressure fields are expressed in terms of harmonic spheroidal eigenfunctions. Connection formulae are obtained for the case of axisymmetric flows, which relate the spheroidal harmonic eigenfunctions of the Papkovich-Neuber representation with the semiseparable spheroidal stream eigenfunctions. In the case of axisymmetric spheroidal flows the Papkovich-Neuber approach is equivalent to the Stokes stream function approach, but the three-dimensional representation offers certain important advantages. Particle-in-cell models for Stokes flow through a swarm of particles are of substantial practical interest, because they provide a relatively simple platform for the analytical or semianalytical solution of heat and mass transport problems. The early versions of these models were concerned with spherical particles. For this reason particle-in-cell models for spheroidal particles were developed more recently. The flexibility of the Papkovich-Neuber differential representation is demonstrated by solving the problem of the flow in a fluid cell filling the space between two confocal spheroidal surfaces with Kuwabara-type boundary conditions.
A magnetic flux stabilizer for the objective lens of a corrected electron microscope

A magnetic flux stabilizer for the main lens in a corrected electron microscope is described. The stabilizing system consists of a 0.1 A current supply, stable to 0.3 ppm/min, and an additional flux regulating system. Flux variations are detected by an induction coil. A flux stability of 10-7 over ten seconds was obtained.
Almost sure characterization of Martingales

Let be an arbitrary set with be a complete filtered probability space such that F 0 is trivial and complete; χ be a countable family of real adapted stochastic processes on Ξ. We provide a necessary and sufficient condition for the existence of a probability measure Q, equivalent to the original measure P, under which every process is a martingale. Furthermore, this condition is invariant under substitution of P with an equivalent probability measure; hence the theorem characterizes those real adapted stochastic processes on Ξ which can become martingales under some equivalent probability measure. The theorem we present allows us also to give a satisfactory solution to the so called Fundamental Problem of Asset Pricing which arises in Mathematical Finance; we further provide the financial interpretation of the “no-free-lunch” condition which is equivalent to the existence of a “risk-neutral measure”.
Planetary nebulae as observational constraints in chemical evolution models for NGC 6822

Aims. Chemical evolution models are useful for understanding the formation and evolution of stars and galaxies. Model predictions will be more robust when more observational constraints are used. We present chemical evolution models for the dwarf irregular galaxy NGC 6822 using chemical abundances of old and young planetary nebulae (PNe) and H ii regions as observational constraints. We use two sets of chemical abundances, one derived from collisionally excited lines (CELs) and one from recombination lines (RLs). We use our models as a tool to distinguish between both procedures for abundance determinations. Methods. In our chemical evolution code the chemical contribution of low and intermediate mass stars is time-delayed, while for the massive stars the chemical contribution follows the instantaneous recycling approximation. Our models have two main free parameters: the mass-loss rate of a well-mixed outflow and the upper mass limit, Mup, of the initial mass function (IMF). To reproduce the gaseous mass and the present-day O/H value we need to vary the outflow rate and the Mup value. Results. We calculate two models with different Mup values that reproduce the constraints adequately. The abundances of old PNe agree with our models and support the star-formation history derived independently from photometric data. Both require an early wellmixed wind, lasting 5.3 Gyr, to reproduce the observed gaseous mass in the galaxy. In addition, by assuming a fraction of binaries producing SNIa of 1%, the models fit the Fe/H abundance ratio as derived from A supergiants. The first model (M4C), which assumes Mup = 40 M� , fits within errors smaller than 2σ the O/H, Ne/H, S/H, Ar/ Ha nd Cl/H abundances obtained from CELs for old and young PNe and H ii regions. The second model (M1R), which adopts Mup = 80 M� , reproduces within 2σ errors the O/H, C/H, Ne/H and S/H abundances adopted from RLs. Both models reproduce the increase of the O, Ne, S, and Ar elements during the last 6 Gyr. We are not able to match the observed N/O ratios in either case, which suggests that the N yields of LIMS need to be improved. Model
Gamma-induced attenuation in normal single-mode and multimode, Ge-doped and P-doped optical fibers: A fiber optic dosimeter for low dose levels

Ge-doped, P-doped, normal single-mode (SM) and multimode (MM) optical fibers were exposed to Cobalt-60 gamma radiation at dose rates of 0.5 and 3.0 Gy/min, typical radiotherapy dose rates. A CCD-based fiber optic spectrometer was used to measure the real-time absorption spectra of these fibers in the visible region. Experimental results have shown that P-doped fiber is the most radiation-sensitive of the fibers tested. At the wavelength of 502 nm, the radiation-induced loss in P-doped fiber shows a linear relationship with the total dose with no dose-rate dependence. This indicates that dose rates have no influence on a fiber optic dosimeter operating at this wavelength. The radiation-induced losses in normal MM fibers, Ge-doped MM fibers, and Ge-doped SM fibers are shownto be dose-rate dependent. PACS No.: 42.62nBe, 42.81-i
The influence of finite Larmor radius effects on the radial interchange motions of plasma filaments

The influence of finite Larmor radius (FLR) effects on the perpendicular convection of isolated particle density filaments driven by interchange motions in magnetized plasmas is investigated using a two-moment gyrofluid model. By means of numerical simulations on a two-dimensional, bi-periodic domain perpendicular to the magnetic field, it is demonstrated that the radial velocities of the blob-like filaments are roughly described by the inertial scaling, which prescribes a velocity proportional to the square root of the summed electron and ion pressures times the square root of the blob width. Due to FLR effects, the poloidal up-down symmetry in the particle density field observed in the zero Larmor radius limit is broken. The symmetry breaking implies a poloidal motion of the blobs in the B×∇B direction. At later times, the direction of the poloidal motion is reversed when the blob is decelerated. It is shown that the spatial structure of the blobs depends on the ratio of the ion gyroradius to the initia.
Broad-band flux density variations of the extragalactic radio source 1611+343

A flux density outburst at low radio frequencies (less than about 1 GHz) has been observed in the extragalactic radio source 1611+343 (= DA 406). Observations in the period from June 1976 to September 1978 were made with several telescopes covering the frequency range from 0.325 to 15.5 GHz. The outburst appears to have been simultaneous at all observed frequencies and had a steep spectrum above 0.400 GHz. Some physical implications of these observations are discussed.
Sudden disappearance of Vela X-1 pulses

On rapporte l'observation par Tenma d'une chute brutale de l'intensite RX de Vela X-1 a moins d'un dixieme de son niveau anterieur en quelques dixiemes de seconde. L'intensite s'est maintenue a ce niveau de 18 min a 78 min. Pendant cette periode le spectre a presente une decroissance generale a toutes les energies ce qu'on ne peut attribuer a une augmentation de l'absorption circumstellaire
Closest point projection in contact mechanics: existence and uniqueness for different types of surfaces

In most contact algorithms especially in case of large deformations the closest point projection (CPP) procedure is necessarily involved in order to check the contact conditions. Despite the number of publications on numerical contact algorithms there are no complete results about existence and uniqueness of the CPP procedure for arbitrary surfaces. The current contribution is aimed to fill this void. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Decision surface estimate of nonlinear system stability domain by Lie series method

The Lie series recursive algorithm for Zubov's partial differential equation is used to generate two sets of points, where one represents the exact asymptotic stability boundary of an equilibrium state of the nonlinear system under consideration and the other is interior to it. Based on these two sets of data as training samples of two classes, a decision hypersurface can be determined such that it is a close approximation of the asymptotic stability boundary.
External optical feedback effects on semiconductor injection laser properties

Influences on the semiconductor laser properties of external optical feedback, i.e., return of a portion of the laser output from a reflector external to the laser cavity, have been examined. Experimental observations with a single mode laser is presented with analysis based on a compound cavity laser model, which has been found to explain essential features of the experimental results. In particular, it has been demonstrated that a laser with external feedback can be multistable and show hysteresis phenomena, analogous to those of non-linear Fabry-Perot resonator. It has also been shown that the dynamic properties of injection lasers are significantly affected by external feedback, depending on interference conditions between returned light and the field inside the laser diode.
Dynamic roughness model for large-eddy simulation of turbulent flow over multiscale, fractal-like rough surfaces

Many flows especially in geophysics involve turbulent boundary layers forming over rough surfaces with multiscale height distribution. Such surfaces pose special challenges for large-eddy simulation (LES) when the filter scale is such that only part of the roughness elements of the surface can be resolved. Here we consider LES of flows over rough surfaces with power-law height spectra Eh(k) ~ kβs (−3 ≤ βs < −1), as often encountered in natural terrains. The surface is decomposed into resolved and subgrid-scale height contributions. The effects of the unresolved small-scale height fluctuations are modelled using a local equilibrium wall model (log-law or Monin–Obukhov similarity), but the required hydrodynamic roughness length must be specified. It is expressed as the product of the subgrid-scale root-mean-square of the height distribution and an unknown dimensionless quantity, α, the roughness parameter. Instead of specifying this parameter in an ad hoc empirical fashion, a dynamic methodology is proposed based on test-filtering the surface forces and requiring that the total drag force be independent of filter scale or resolution. This dynamic surface roughness (DSR) model is inspired by the Germano identity traditionally used to determine model parameters for closing subgrid-scale stresses in the bulk of a turbulent flow. A series of LES of fully developed flow over rough surfaces are performed, with surfaces built using random-phase Fourier modes with prescribed power-law spectra. Results show that the DSR model yields well-defined, rapidly converging, values of α. Effects of spatial resolution and spectral slopes are investigated. The accuracy of the DSR model is tested by showing that predicted mean velocity profiles are approximately independent of resolution for the dynamically computed values of α, whereas resolution-dependent results are obtained when using other, incorrect, α values. Also, strong dependence of α on βs is found, where α ranges from α ~ 0.1 for βs = −1.2 to α ~ 10−5 for βs = −3.
Implementation and value of using a split-plot reader design in a study of digital breast tomosynthesis in a breast cancer assessment clinic

The rapid evolution in medical imaging has led to an increased number of recurrent trials, primarily to ensure that the efficacy of new imaging techniques is known. The cost associated with time and resources in conducting such trials is usually high. The recruitment of participants, in a medium to large reader study, is often very challenging as the demanding number of cases discourages involvement with the trial. We aim to evaluate the efficacy of Digital Breast Tomosynthesis (DBT) in a recall assessment clinic in Australia in a prospective multi-reader-multi-case (MRMC) trial. Conducting such a study with the more commonly used fully crossed MRMC study design would require more cases and more cases read per reader, which was not viable in our setting. With an aim to perform a cost effective yet statistically efficient clinical trial, we evaluated alternative study designs, particularly the alternative split-plot MRMC study design and compared and contrasted it with more commonly used fully crossed MRMC study design. Our results suggest that ‘split-plot’, an alternative MRMC study design, could be very beneficial for medium to large clinical trials and the cost associated with conducting such trials can be greatly reduced without adversely effecting the variance of the study. We have also noted an inverse dependency between number of required readers and cases to achieve a target variance. This suggests that split-plot could also be very beneficial for studies that focus on cases that are hard to procure or readers that are hard to recruit. We believe that our results may be relevant to other researchers seeking to design a medium to large clinical trials.
Radio haloes, cluster mergers, and cooling flows.

Radio haloes are rarely found in galaxy clusters with cooling flows, and those that are found are different from the canonical haloes such as that in the Coma cluster. I propose that the big cluster radio haloes are transient, being formed in large cluster mergers and then fading. The small haloes in cooling flows are a result of magnetic field compression and reacceleration of old relativistic electrons by the cooling flow
Turbulent intensity and Reynolds number effects on an airfoil at low Reynolds numbers

This work investigates the aerodynamics of a NACA 0012 airfoil at the chord-based Reynolds numbers (Rec) from 5.3 × 103 to 2.0 × 104. The lift and drag coefficients, CL and CD, of the airfoil, along with the flow structure, were measured as the turbulent intensity Tu of oncoming flow varies from 0.6% to 6.0%. The analysis of the present data and those in the literature unveils a total of eight distinct flow structures around the suction side of the airfoil. Four Rec regimes, i.e., the ultra-low ( 5.0 × 106), are proposed based on their characteristics of the CL-Rec relationship and the flow structure. It has been observed that Tu has a more pronounced effect at lower Rec than at higher Rec on the shear layer separation, reattachment, transition, and formation of the separation bubble. As a result, CL, CD, CL/CD and their dependence on the airfoil angle of attack all vary with Tu. So does the critical Reynolds number Rec,.
Tunable Bandgap in BiFeO 3 Nanoparticles: The Role of Microstrain and Oxygen Defects

We demonstrate a tunable bandgap from 2.32 eV to 2.09 eV in phase-pure BiFeO3 by controlling the particle size from 65 nm to 5 nm. Defect states due to oxygen and microstrain show a strong dependence on BiFeO3 particle size and have a significant effect on the shape of absorbance curves. Oxygen-defect induced microstrain and undercoordinated oxygen on the surface of BiFeO3 nanoparticles are demonstrated via HRTEM and XPS studies. Microstrain in the lattice leads to the reduction in rhombohedral distortion of BiFeO3 for particle sizes below 30 nm. The decrease in band gap with decreasing particle size is attributed to the competing effects of microstrain, oxygen defects, and Coulombic interactions.
Nitrogen incorporation in ultrathin gate dielectrics: A comparison of He/N2O and He/N2 remote plasma processes

Ultrathin Si oxynitride films grown by low-temperature remote plasma processing were examined by on-line Auger electron spectroscopy and angle-resolved x-ray photoelectron spectroscopy to determine the concentration, spatial distribution, and chemical bonding of nitrogen. The films were grown at 300 °C on Si(100) substrates using two radio-frequency remote plasma processes: (i) He/N2O remote plasma-assisted oxidation (RPAO) and (ii) two-step remote plasma oxidation/nitridation. A 5 min He/N2O RPAO process produces a 2.5 nm oxynitride film incorporating approximately 1 monolayer of nitrogen at the Si–SiO2 interface. The interfacial nitrogen is bonded in a N–Si3 configuration, as in silicon nitride (Si3N4). By comparison, a 90 s He/N2 remote plasma exposure of a 1 nm oxide (grown by 10 s He/O2 RPAO) consumes substrate Si atoms creating a 1 nm subcutaneous Si3N4 layer. The nitrogen areal density obtained via the two-step process depends on the initial oxide thickness and the He/N2 remote plasma exposure time. Moreover, as the oxide thickness is increased (by increasing the He/O2 remote plasma exposure), the nitrogen distribution shifts away from the Si–SiO2 interface and into the oxide. More nitrogen with a tighter distribution is incorporated using He versus Ar dilution. Insight into the remote plasma chemistry was provided by optical emission spectroscopy. Strong N2 first positive and second positive emission bands were observed for He/N2O and He/N2 remote plasmas indicating the presence of N2 metastables and ground-state N atoms.Ultrathin Si oxynitride films grown by low-temperature remote plasma processing were examined by on-line Auger electron spectroscopy and angle-resolved x-ray photoelectron spectroscopy to determine the concentration, spatial distribution, and chemical bonding of nitrogen. The films were grown at 300 °C on Si(100) substrates using two radio-frequency remote plasma processes: (i) He/N2O remote plasma-assisted oxidation (RPAO) and (ii) two-step remote plasma oxidation/nitridation. A 5 min He/N2O RPAO process produces a 2.5 nm oxynitride film incorporating approximately 1 monolayer of nitrogen at the Si–SiO2 interface. The interfacial nitrogen is bonded in a N–Si3 configuration, as in silicon nitride (Si3N4). By comparison, a 90 s He/N2 remote plasma exposure of a 1 nm oxide (grown by 10 s He/O2 RPAO) consumes substrate Si atoms creating a 1 nm subcutaneous Si3N4 layer. The nitrogen areal density obtained via the two-step process depends on the initial oxide thickness and the He/N2 remote plasma exposure time.