Miracle-dz/UniFAR-FTUs huggingface dataset:
Interstellar Gas Mass Functions: Fractality and Scale Dependence

We present a theoretical model for the observed mass functions (MF’s) of interstellar clouds, and test it by comparison with interferometrically observedMF’s. We consider the time evolution of velocities using the stochastic differential Langevin equation for the objects (in fact gas clumps of sizes below 1 pc) under Brownian motion, with friction and magnetic field. We also study geometrical binding, and hence the implications of sizes of the regions in which the gas clouds move, and also of the departures from sphericity of the clouds themselves. The size of the global region in which the objects move under the influence of the general dynamics of the galaxy leads to a box-effect modelled as a Chandrasekhar barrier, which naturally leads to the superposition of Gaussian distributions over different ranges of displacement, and with progressively decreasing amplitude. This accounts for the general power law trend observed for the MF’s, as well as its accompanying peaked structure. These results fit well the observed distributions even in very low mass ranges, which show global power law characteristics (scale independence, fractality, departures from sphericity for individual clouds), accompanied by turnovers, for a wide range of masses, characteristics of Gaussians (scale dependence, a tendency for clouds to be spherical).
Review of elastic and electromagnetic wave propagation in horizontally layered media

The objective of this paper is to provide a unified treatment of elastic and electromagnetic (EM) wave propagation in horizontally layered media for which the parameters in the partial differential equations are piece‐wise continuous functions of only one spatial variable. By applying a combination of Fourier, Laplace, and Bessel transforms to the partial differential equations describing the elastic or EM wave propagation I obtain a system of 2n linear ordinary differential equations. The 2n×2n coefficient matrix is partitioned into 4n×n submatrices. By a proper choice of variables, the diagonal submatrices are zero and the off‐diagonal submatrices are symmetric. All the results in the paper are derived from the symmetry properties of this general equation. In the appendices it is shown that three‐dimensional elastic waves, cylindrical P‐SV waves, acoustic waves, and electromagnetic waves in isotropic layered media can all be represented by an equation with the same properties. The symmetry properties of.
Maximum Likelihood Estimation of Correlation Between Variates Having Equal Coefficients of Variation

For a sample of n pairs of observations from a bivariate normal distribution in which X and Y have the same coefficient of variation c, we derive the equations for the m.l. estimator of ρ. The efficiency of the Pearson correlation coefficient r relative to is studied asymptotically and for small samples. It is shown for certain values of c and ρ that r is inefficient. An application is described for choosing the optimum standard in the clinical chemistry laboratory.
Two-microphone system using linear prediction and noise reconstruction

In this paper, we propose a new adaptive microphone system characterized by a linear prediction circuit inserted before a noise reconstruction filter corresponding to the adaptive delay used in conventional systems. The insertion of the circuit provides various advantages to the adaptive microphone system. One is that steering a null for a noise source becomes possible in spite of an incident speech signal, although conventional systems require the stopping of the null steering during this incidence. Another advantage is that the new microphone system works as an omnidirectional microphone for the speech signal. Consequently, setting the microphones at arbitrary intervals is allowed. For example, building a microphone in a handset and another one in a telephone baseset is possible; thereby, a higher noise reduction effect is expected. We also verify the performance of the proposed system using an experimental system.
Asymptotically anti-de Sitter space-times

The structure of the gravitational field at infinity of asymptotically anti-de Sitter space-time is analysed in detail using conformal techniques. It is found that the situation differs from that in the case of asymptotically Minkowskian space-times in a number of respects, primarily because J is now time-like rather than null. In particular, the asymptotic symmetry group is quite different from the BMS group, and there is no analogue of the Bondi news. The analysis also introduces definitions of 'conserved' quantities at J in terms of the curvature tensor which are free of the ambiguities present in the previous definitions based on the deviation of the physical metric from an anti-de Sitter background.
Research on Polarization Image Fusion Using Tetrolet Transform

Tetrolets are Haar-type wavelets whose supports are tetrominoes which are shapes made by connecting four equal-sized squares. Firstly, the magnitude of polarization image and angle of polarization image can be decomposed into low-frequency coefficients and high-frequency coefficients with multi-scales and multi-directions using tetrolet transform. For the low-frequency coefficients, the average fusion method is used. For the each directional high frequency sub-band coefficients, the larger value of region energy information measurement is used to select the better coefficients for fusion. At last the fused image can be obtained by utilizing inverse transform for fused tetrolet coefficients. Experimental results show that the proposed method can detect image features more effectively and the fused image has better subjective visual effect.
Affordable Compressible LES of Airfoil-Turbulence Interaction in a Free Jet

Turbulence-interaction noise due to homogeneous isotropic turbulence impacting on a thick cambered NACA651210 airfoil with a significant spanwise extent (40%) has been simulated for the first time at high Reynolds number (Rec=6.5×105) by a compressible Large Eddy Simulation (LES) accounting for the installation effects. The full wind-tunnel has been simulated by a 2D Unsteady Reynolds-Averaged Navier-Stokes (URANS) simulation that provides the realistic boundary conditions for the LES on a restricted domain embed- ded in the potential core of the wind-tunnel jet. Radiative boundary conditions have been applied all around the LES domain to prevent any reflection or drift of flow parameters at the LES boundaries. The mean URANS flow field was also used for a 2D non-linear Euler computation. The same synthetic turbulence model has been used at the inlet for both methods. Comparison with experimental data show excellent agreement with the Euler results and proper noise level and directivity for the LES when the sources are restricted to the leading edge area. Yet the LES also show some extra noise sources at the trailing edge caused by a large recirculation bubble close to the leading edge yielding some large vorticity up to the trailing edge, and a late transition on the suction side.
Effect of temperature and elastic constant on the piezoresistivity of silicon nanobeams

A strain k⋅p model is used to investigate lattice temperature dependence of the piezoresistivity of p-doped silicon nanobeams in the range of 100–600 K, based on the self-consistent solution to the coupled Schrodinger–Poisson equations. According to quasiharmonic approximation, an analytical semicontinuum atomistic lattice model is presented to describe the effect of size and temperature on elastic constants of the silicon nanobeam by using the anharmonic Keating model. The result presented here indicates the piezoresistive coefficient of the silicon nanobeam, which is dependent on quantum confinement effects, has a negative and nonlinear temperature coefficient. A quantitative comparison of the piezoresistive coefficients calculated with and without considering the elastic constant correction shows that it is crucial to incorporate the size-dependent elastic constant correction in order to quantify the piezoresistivity.
Confidence intervals for linear discrete inverse problems with a non-negativity constraint

We consider the problem of constructing confidence intervals for linear functionals βtx of a non-negative vector x given discrete indirect noisy observations y = Kx + ε. The intervals are defined by the range of the functional over constrained projected contours of a quadratic data misfit function. Rust and O'Leary (1994 J. Comput. Graph. Stat.3 67) derived similar intervals but we show that some conditions are required for the intervals to have the correct coverage and provide valid intervals for the cases when the conditions are not met. The problem is reduced to two simple cases: for β > 0 a closed formula for the intervals can be used on reduced one-dimensional data without the need to solve an optimization problem. For β ≯ 0 the optimization is reduced to a two-dimensional problem with K = I but a non-diagonal covariance matrix.
Nanoflares and the solar X-ray corona

Observations of the sun with high time and spatial resolution in UV and X-rays show that the emission from small isolated magnetic bipoles is intermittent and impulsive, while the steadier emission from larger bipoles appears as the sum of many individual impulses. We refer to the basic unit of impulsive energy release as a nanoflare. The observations suggest, then, that the active X-ray corona of the sun is to be understood as a swarm of nanoflares. This interpretation suggests that the X-ray corona is created by the dissipation at the many tangential discontinuities arising spontaneously in the bipolar fields of the active regions of the sun as a consequence of random continuous motion of the footpoints of the field in the photospheric convection. The quantitative characteristics of the process are inferred from the observed coronal heat input. 105 references.
A thickened flame model for large eddy simulations of turbulent premixed combustion

A subgrid scale model for large eddy simulations of turbulent premixed combustion is developed and validated. The approach is based on the concept of artificially thickened flames, keeping constant the laminar flame speed sl0. This thickening is simply achieved by decreasing the pre-exponential factor of the chemical Arrhenius law whereas the molecular diffusion is enhanced. When the flame is thickened, the combustion–turbulence interaction is affected and must be modeled. This point is investigated here using direct numerical simulations of flame–vortex interactions and an efficiency function E is introduced to incorporate thickening effects in the subgrid scale model. The input parameters in E are related to the subgrid scale turbulence (velocity and length scales). An efficient approach, based on similarity assumptions, is developed to extract these quantities from the resolved velocity field. A specific operator is developed to exclude the dilatational part of the velocity field from the estimation of.
On entropy consistency of large time step schemes I: the Godunov and Glimm schemes

This paper shows for scalar conservation laws with a convex flux function that the large time step approximation of weak solutions gives entropy solutions in the limit if the Courant number is between $\tfrac{1}{2}$ and 1. For flux functions with constant curvature, monotonicity, or monotone initial data the results extend to larger Courant numbers. A continuity argument gives this result also for the case of fluxes with almost constant curvature.
Design of a 1 MVA high T/sub c/ superconducting transformer

A 1 MVA transformer using BSCCO-2223 high T/sub c/ superconducting (HTS) tapes was designed. The rated voltages of each sides of the transformer for primary and secondary are 22.9 kV and 6.6 kV respectively. Double pancake HTS windings, which have advantages of insulations and distribution of high voltage, were adopted. Four HTS tapes were wound in parallel for the windings of low voltage side. Each winding was composed of several double pancake windings and four parallel conductors of secondary winding were transposed in order to distribute the currents equally in each conductor. The core of the transformer was designed as a shell type core made of laminated silicon steel plate and the core is separated from the windings by a cryostat with a room temperature bore. Configuration of the cryostat made of nonmagnetic and nonconducting material and a liquid nitrogen sub-cooling system were used in order to maintain the coolant's temperature of 65 K.
Fault Tolerant Technique for Processor Control Path to Mitigate SEUs in FPGA

Single-Event-Upset is a transient fault that occurs during the lifetime of the circuit operation. These faults lead to system failure if it occurs in machine-critical applications. Multiple SRAM-based Field Programmable gateway (FPGA) is made available with the in-built processor for designing adaptive hardware systems. Faults in the control path of the processor lead to system failure as it changes the instruction itself. This paper proposes a novel solution to mitigate the single event upsets in the control paths of the processor by introducing a novel encoding technique for the control path element of the processor. The proposed techniques are verified on Proasic3e FPGA and compared with traditional mitization techniques.
Parametric array in air

An experimental investigation of the parametric array in air was conducted using a circular piston transducer which produced spherically spreading, collinear, primary beams at frequencies of 18.6 and 23.6 kHz. Since source levels were not strong (about 110 dB re 0.0002 μbar at 1 ft), the 5−kHz difference frequency signal generated by the parametric array was relatively weak. Because of space limitations, all measurements were made in the nearfield of the array. Spurious difference frequency signals resulting from intermodulation distortion in the receiving system were suppressed by judicious choice of electronic components and by the addition of an acoustical filter in front of the microphone. The classic properties of the parametric array were observed. The 5−kHz beam was narrow, and no minor lobes were evident. The propagation curve first increased with increasing range, reached a broad maximum, and then gradually decreased. Theoretical predictions were based on a perturbation solution of Burgers’ equat.
Towards solving the bent-ray tomographic problem

A new computerized method is described for reconstruction of a refractive index distribution from time-of-flight measurements of radiation/waves passing through the distribution and taken on a known boundary surrounding it. The reconstruction method is a bent-ray computed tomography (CT) approach based on a novel ray description which does not require the ray paths to be known. This allows the refractive index to be found by iterative solution of linear equations, rather than through the computationally intensive procedure of ray tracing, which normally accompanies iterative solutions to problems of this type. Preliminary results show that this method is capable of handling appreciable spatial refractive index variations in large bodies.
HYDRODYNAMIC AND THERMAL CHARACTERISTICS OF CORRUGATED CHANNELS: EXPERIMENTAL APPROACH

Corrugated channels in a plate heat exchanger have probably the most complicated geometry of all flow ducts. To understand the hydrodynamic and thermal characteristics of corrugated channels, a proper balance of theoretical, computational, and experimental approaches is essential. The theoretical approach, which involves the simultaneous solution of the governing equations of fluid dynamics, becomes so complex as to be impractical, except for some special cases and with many simplifying assumptions. The computational approach includes using computers to solve discretized versions of the governing equations of fluid dynamics. This article is focused on an experimental approach which concerns local pressure and local temperature measurements.
Diversity and Regional Variation of Endosymbionts in the Green Peach Aphid, Myzus persicae (Sulzer)

The green peach aphid, Myzus persicae, is globally distributed and an important pest of many economically valuable food crops, largely due to its ability to transmit plant viruses. Almost all aphids, including M. persicae, carry the obligate symbiont Buchnera aphidicola, which provides essential amino acids that aphids cannot obtain from the phloem of plants themselves. Many aphids also harbor facultative (secondary) endosymbionts, which provide benefits under specific ecological conditions. In this study, we screened for secondary endosymbionts in M. persicae, with a particular focus on Australian populations where this species is growing in status as a major agricultural pest. We compared 37 Australian M. persicae populations with other populations, including 21 field populations from China and 15 clones from the UK, France, Italy, Greece, USA, Spain, South Korea, Chile, Japan and Zimbabwe. No secondary endosymbionts were identified in M. persicae samples outside of China, despite samples covering a wide geographic range and being collected from several host plant families. We detected two secondary endosymbionts (Rickettsia, Spiroplasma) in Chinese samples, although diversity appeared lower than detected in a recent study. We also found very high clonal diversity in Chinese samples based on DNA microsatellite markers in comparison with lower clonal diversity from Australia. These patterns may indicate a higher diversity of secondary endosymbionts (and clonal diversity) in the native range of M. persicae when compared to its invasive range.
Lightning Protection With a Differentiated Arrester Configuration for Distribution Networks Using a Multi-Objective Optimization Procedure

In addition to insulator flashover, lightning damage of surge arresters (SAs) is also considered in evaluating the lightning performance of a distribution network. This article presents a novel multi-objective optimization framework for designing differentiated SA protection, by minimizing both the flashover number and SA damage rate. An artificial neural network and an energy-distribution surrogate model are developed for the efficient evaluation of these two targets in an optimization process. The samples for building these models are generated with a hybrid simulation approach together with a Monte Carlo method. It is concluded that the surge energy into an SA generally follows a log-normal probabilistic distribution. The mean of energy absorption decays exponentially with the distance to the stroke location. Differentiated SA configurations for a 10 kV distribution network are then identified by balancing the need of minimizing these two targets. It is found that when increasing the SA number, the damage rate becomes dominant and SAs are recommended to be located close to the dead-end poles in sub-feeders. Otherwise, the annual flashover number becomes dominant and SAs tend to be located around the junction poles on the main feeder. When the annual flashover number is primarily addressed, the pole-group selection strategy is the best one due to its simplicity and better performance. However, if both the annual flashover number and damage rate are of concern, the proposed optimization procedure is recommended to achieve a balanced lightning performance.
Pulsed fiber laser with 30W output power at 532nm

We have developed innovative high power polarized 1064nm pulsed fiber laser for efficient nonlinear frequency conversion and by frequency doubling its output generated 30W of average power with 68% conversion efficiency at 532nm. This new 1064nm pulsed fiber laser operates at 1.8MHz repetition rate with 1.3ns pulse duration and close to bandwidth-limited spectral linewidth. The developed laser delivers 46W average power at 1064nm in the linearly polarized output beam with a polarization extinction ratio 20dB. This laser has a truly solid-state design required for deployment into the industrial environment and can be used for nonlinear frequency conversion to generate high power emission in the visible and UV parts of optical spectrum as well as for other applications. The overall 16% efficiency demonstrated in generating 532nm is believed to be the highest wall plug efficiency achieved by any solid-state or fiber lasers with visible output. We expect that over 20% total efficiency for the fiber laser with tens of watts output in the green spectral range will be available.
The spectrum of an R-homomorphism

Abstract Let E be a real Banach space ordered by a closed, normal and generating cone. Suppose also that the order induced on E has the Riesz decomposition property. It is shown that if T:E → E is a positive linear operator with the property that y, z, a ∈ E with a ≧ Ty, Tz implies there is x ∈ E with x ≧ y, z and a ≧ Tx then the approximate point spectrum and spectrum of T are cyclic subsets of the complex plane. That is, if α = |α|γ lies in one of these sets then so does |α|γk for all integers k.
A divergence‐free interpolation scheme for the immersed boundary method

The immersed boundary approach for the modeling of complex geometries in incompressible flows is examined critically from the perspective of satisfying boundary conditions and mass conservation. It is shown that the system of discretized equations for mass and momentum can be inconsistent, if the velocity is used in defining the force density to satisfy the boundary conditions. As a result, the velocity is generally not divergence free and the pressure at locations in the vicinity of the immersed boundary is not physical. However, the use of the pseudo‐velocities in defining the force density, as frequently done when the governing equations are solved using a fractional step or projection method, combined with the use of the specified velocity on the immersed boundary, is shown to result in a consistent set of equations which allows a divergence‐free velocity but, depending on the time step, is shown to have the undesirable effects of inaccurately satisfying the boundary conditions and allowing a significant permeability of the immersed boundary. If the time step is reduced sufficiently, the boundary conditions on the immersed boundary can be satisfied. However, this entails an unacceptable increase in computational expense. Two new methods that satisfy the boundary conditions and allow a divergence‐free velocity while avoiding the increased computational expense are presented and shown to be second‐order accurate in space. The first new method is based on local time step reduction. This method is suitable for problems where the immersed boundary does not move. For these problems, the first new method is shown to be closely related to the second new method. The second new method uses an optimization scheme to minimize the deviation from the interpolation stencil used to represent the immersed boundary while ensuring a divergence‐free velocity. This method performs well for all problems, including those where the immersed boundary moves relative to the grid. Additional results include showing that the force density that is added to satisfy the boundary conditions at the immersed boundary is unbounded as the time step is reduced and that the pressure in the vicinity of the immersed boundary is unphysical, being strongly a function of the time step. A method of computing the total force on an immersed boundary which takes into account the specifics of the numerical solver used in the iterative process and correctly computes the total force irrespective of the residual level is also presented. Copyright © 2007 John Wiley & Sons, Ltd.