Miracle-dz/UniFAR-FTUs huggingface dataset:
Power-Law Fluid Flow Passing Two Square Cylinders in Tandem Arrangement

Two-dimensional laminar flow of a power-law fluid passing two square cylinders in a tandem arrangement is numerically investigated in the ranges of 1< Re< 200 and 1 ≤ G ≤ 9. The fluid viscosity power-law index lies in the range 0.5 ≤ n ≤ 1.8, which covers shear-thinning, Newtonian and shear-thickening fluids. A finite volume code based on the SIMPLEC algorithm with nonstaggered grid is used. In order to discretize the convective and diffusive terms, the third order QUICK and the second-order central difference scheme are used, respectively. The influence of the power-law index, Reynolds number and gap ratio on the drag coefficient, Strouhal number and streamlines are investigated, and the results are compared with other studies in the literature to validate the methodology. The effect of the time integration scheme on accuracy and computational time is also analyzed. In the ranges of Reynolds number and power-law index studied here, vortex shedding is known to occur for square cylinders in tandem. This study represents the first systematic investigation of this phenomenon for non-Newtonian fluids in the open literature. In comparison to Newtonian fluids, it is found that the onset of leading edge separation occurs at lower Reynolds number for shear-thinning fluids and is delayed to larger values for shear-thickening fluids.
Replication and Researchers' Understanding of Confidence Intervals and Standard Error Bars.

Confidence intervals (CIs) and standard error bars give information about replication, but do researchers have an accurate appreciation of that information? Authors of journal articles in psychology, behavioral neuroscience, and medicine were invited by email to visit a Web site and indicate on a figure where they judged replication means would plausibly fall. Responses from 263 researchers suggest that many leading researchers in the 3 disciplines underestimate the extent to which future replications will vary. A 95% CI will on average capture 83.4% of future replication means. A majority of respondents, however, held the confidence-level misconception that a 95% CI will on average capture 95% of replication means. Better understanding of CIs is needed if they are to be successfully used more widely in psychology.
Perceptual ringing metric to evaluate the quality of images restored using blind deconvolution algorithms

Linear space-invariant image restoration algorithms often introduce ringing effects near sharp intensity transitions. A ringing metric to evaluate the quality of images restored using iterative deconvolution algorithms is presented. According to the types of ringing artifacts, two ringing metrics are used to assess the restored images based on the analysis of ringing artifacts. An overall ringing metric is presented based on the two ringing metrics. The experimental results validate that the proposed method performs well over a wide range of restoration image ringing level assessments. Consequently, the proposed model has a good agreement with the ratings from an observer in subjective experiments.
On Formally Undecidable Propositions of Principia Mathematica and Related Systems

Gödel’s famous proof [2, 1] is highly interesting, but may be hard to understand. Some of this difficulty is due to the fact that the notation used by Gödel has been largely replaced by other notation. Some of this difficulty is due to the fact that while Gödel’s formulations are concise, they sometimes require the readers to make up their own interpretations for formulae, or to keep definitions in mind that may not seem mnemonic to them. This document is a translation of a large part of Gödel’s proof. The translation happens on three levels:
Multi-mode vortex-induced vibrations of a flexible circular cylinder

Vortex-Induced Vibration (VIV) is a key issue in deep water riser design. Water depths up to 3000 m are found in typical oil extraction areas and in order to extract the oil from the sea bed, flexible slender pipes called risers, are necessary. Risers can experience VIV when exposed to marine currents, because the shedding of vortices downstream of the structure induces forces on it, which may cause vibrations. Design of deep water systems is a challenging engineering problem and the understanding of VIV and its suppression are very active areas of research. The study of this problem is hampered by a lack of good quality measurements and a lack of totally reliable models to predict the response and the fluid loading on risers undergoing VIV. A vertical tension riser model in a stepped current was used to study its response when subject to VIV. The riser, 28 mm in diameter, 13.12 m long and with a mass ratio (mass/displaced mass) of 3.0, was tested in conditions in which the lower 45% was exposed to a uniform current at speeds up to 1 m/s, while the upper part was in still water. Reynolds numbers reached values of approximately 28000. The response in the in-line and cross-flow directions was inferred from measurements of bending strains at 32 equally spaced points along its length. Cross-flow vibrations were observed at modes up to the 8 and in-line up to the 14. The response included significant contributions from several modes, all at a frequency controlled by lock-in of the dominant mode. Measurements of in-line and cross-flow displacements reveal a strong dependence on the motion. A finite element method technique has been developed to model the riser and used in conjunction with the experimental response data, to calculate in-line and cross-flow force distributions along the axis of the riser.
On bootstrap resampling and iteration

SUMMARY We propose a single unifying approach to bootstrap resampling, applicable to a very wide range of statistical problems. It enables attention to be focused sharply on one or more characteristics which are of major importance in any particular problem, such as coverage error or length for confidence intervals, or bias for point estimation. Our approach leads easily and directly to a very general form of bootstrap iteration, unifying and generalizing present disparate accounts of this subject. It also provides simple solutions to relatively complex problems, such as a suggestion by Lehmann (1986) for 'conditionally' short confidence intervals. We set out a single unifying principle guiding the operation of bootstrap resampling, applicable to a very wide range of statistical problems including bias reduction, shrinkage, hypothesis testing and confidence interval construction. Our principle differs from other approaches in that it focuses attention directly on a measure of quality or accuracy, expressed in the form of an equation whose solution is sought. A very general form of bootstrap iteration is an immediate consequence of iterating the empirical solution to this equation so as to improve accuracy. When employed for bias reduction, iteration of the resampling principle yields a competitor to the generalized jackknife, enabling bias to be reduced to arbitrarily low levels. When applied to confidence intervals it produces the techniques of Hall (1986) and Beran (1987). The resampling principle leads easily to solutions of new, complex problems, such as empirical versions of confidence intervals proposed by Lehmann (1986). Lehmann argued that an 'ideal' confidence interval is one which is short when it covers the true parameter value but not necessarily otherwise. The resampling principle suggests a simple empirical means of constructing such intervals. Section 2 describes the general principle, and ? 3 shows how it leads naturally to bootstrap iteration. There we show that in many problems of practical interest, such as bias reduction and coverage-error reduction in two-sided confidence intervals, each iteration reduces error by the factor n-1, where n is sample size. In the case of confidence intervals our result sharpens one of Beran (1987), who showed that coverage error is reduced by the factor n-2 in two-sided intervals. The main exception to our n-1 rule is coverage error of one-sided intervals, where error is reduced by the factor n-A at each iteration. Our approach to bootstrap iteration serves to unify not just the philosophy of iteration for different statistical problems, but also different techniques of iteration for the same
Beating capillarity in thin film flows

The combination of substrate unevenness and capillarity is known to induce far‐reaching perturbations at the free surface of thin liquid films. These might be undesired and this paper explores the possibility to control the free surface of thin liquid films to give it a prescribed profile by a suitable design of the underlying substrate. This corresponds to the inverse of the widely studied forward problem, which considers the effect of substrate unevenness on a free surface. Assuming that the steady free surface profile can be described by the lubrication approximation, this optimal control problem is shown to be governed by a first‐order partial differential equation, which is solved numerically using the method of characteristics. The proposed method is successfully tested for a range of desired free surface profiles and the domain of existence of a solution to the inverse problem is probed. Expectedly, it is shown that, owing to surface tension, not all free surface profiles can be achieved but in some cases capillarity can be beaten and a prescribed free surface profile obtained. Copyright © 2009 John Wiley & Sons, Ltd.
Optimizing the precision of toxicity threshold estimation using a two-stage experimental design

An important consideration for risk assessment is the existence of a threshold, i.e., the highest toxicant dose where the response is not distinguishable from background. We have developed methodology for finding an experimental design that optimizes the precision of threshold model parameter estimation for single-chemical threshold experiments. Being interested in precisely estimating the threshold parameter, we used the D-optimality and the Ds-optimality criteria. The D-optimal design results in parameter estimates as precise as possible in the sense that the likelihood-based confidence region has minimum volume, while the Ds-optimal threshold design results in parameter estimates as precise as possible in that the variance of the threshold parameter estimate is minimized. For nonlinearmodels, optimal designs are a function of the unknown parameters via the information matrix. Therefore, estimates of the parameters must be obtained before the optimal design of the experiment can be found. For this reason, a two-stage D-Ds-optimal design is recommended where the D-optimality criterion is used in the first stage followed by the Ds-optimality criterion in the second stage. The first stage is used for range finding and to obtain good global estimates to supply to the second stage. The second stage results in precise parameter estimates with minimum variance for the threshold parameter estimate. We propose that the use of this two-stage D-Ds-optimal design will provide toxicologists with the experimental parameters necessary to accurately estimate thresholds for risk assessment purposes in a more cost-effective and timely manner.
On the Ability of Different Diffusion Theories to Account for Directly Simulated Diffusion Coefficients

We present direct numerical simulations of charged-particle transport in a turbulent magnetic field. The magnetic field model used in the simulations consists of a composite of statistically homogeneous slab and two-dimensional turbulence representative of solar wind conditions at Earth. This turbulent magnetic field is then added to a uniform background magnetic field. We find that the parallel and perpendicular mean free paths are well described by power laws as a function of rigidity at different turbulence levels. At a low level of turbulence we find that quasi-linear theory and the field line random walk theory for the parallel and perpendicular mean free paths, respectively, provide predictions that are in good agreement with the simulated mean free paths. At intermediate turbulence levels the simulated parallel and perpendicular mean free paths are best accounted for by recently proposed nonlinear theories, while quasi-linear theory and the field line random walk theory overestimate the simulated mean free paths. At high turbulence levels neither quasi-linear theory and the field line random walk theory nor the nonlinear theories provide predictions that are in good agreement with the simulated parallel and perpendicular mean free paths.
Quantum decoherence under phase damping in non-inertial frames

We investigate the quantum decoherence of Dirac fields in a non-inertial system under phase damping channel. The quantum decoherence and the loss of entanglement generated by Unruh radiation will influence each other, and the entanglement disappears only as time tends to infinity whether one or two qubits of system is coupled to the environment.
Charged-Particle Resonance Conditions and Transport Coefficients in Slab-Mode Waves

Transport of charged particles in cold plasma is considered. The full dispersion relation for slab-mode waves is employed, and the quasi-linear particle scattering is discussed. Previous results of the dispersive-wave model on the ion mean free path are recalled and further developed. For small cross-helicities, the model predicts ion mean free paths that are not affected by the steepening of the turbulence spectrum at high wavenumbers, if the dissipation-range spectral index is q < 6. Large cross-helicities, |Hc| ∼ 1, of the left-hand polarized waves, however, imply an approximately constant mean free path of the nonrelativistic protons, which may account for the long-standing flatness problem of the mean free path of solar flare particles. The mean free path in a mixture of slab-mode and isotropic fast-mode waves is also shown to agree with observations only in the case of |Hc| ∼ 1, contradicting a previously published result. Finally, it is shown that, owing to an interplay of resonances with whistlers and proton-cyclotron waves, electron bulk speeds can be considerably larger than the Alfvén speed. This implies limitations on diffusive acceleration of electrons at low Mach number shocks below ultrarelativistic energies.
Drop shape dynamics of a Newtonian drop in a non-Newtonian matrix during transient and steady shear flow

Transient and steady deformation of a single Newtonian drop immersed in a non-Newtonian matrix subjected to a homogeneous shear flow is investigated microscopically. Two model Boger fluids have been used as non-Newtonian matrices. The three-dimensional drop shape is completely determined as observations from both the velocity-vorticity and velocity-velocity gradient plane are available. Start-up and relaxation are investigated varying both the capillary number and the elasticity of the matrix fluid, while the viscosity ratio is kept constant. The extensive data set demonstrates that matrix elasticity reduces the steady drop deformation and promotes droplet orientation, can induce a drop deformation overshoot in the start-up experiments and slows down the relaxation phenomena. The experimental results have been compared with predictions of a phenomenological model [M. Minale, J. Non-Newtonian Fluid Mech. 123, 151–160 (2004)], that is slightly modified in the present work. It shows good agreement with the experimental data up to moderate capillary numbers (Ca≈0.2). For higher Ca, the observed trends are still correctly predicted, although quantitative agreement is less satisfying. A systematic deviation is observed at the end of the relaxation process. This result, together with a systematic, quantitative discrepancy in the experimental data between the two Boger fluids, suggests that the underlying rheological model is probably too simplistic to allow a quantitative prediction of all effects caused by matrix elasticity.Transient and steady deformation of a single Newtonian drop immersed in a non-Newtonian matrix subjected to a homogeneous shear flow is investigated microscopically. Two model Boger fluids have been used as non-Newtonian matrices. The three-dimensional drop shape is completely determined as observations from both the velocity-vorticity and velocity-velocity gradient plane are available. Start-up and relaxation are investigated varying both the capillary number and the elasticity of the matrix fluid, while the viscosity ratio is kept constant. The extensive data set demonstrates that matrix elasticity reduces the steady drop deformation and promotes droplet orientation, can induce a drop deformation overshoot in the start-up experiments and slows down the relaxation phenomena. The experimental results have been compared with predictions of a phenomenological model [M. Minale, J. Non-Newtonian Fluid Mech. 123, 151–160 (2004)], that is slightly modified in the present work. It shows good agreement with the e.
Magnetic Studies on Cu++ Ion in Cupric Acetate Monohydrate Crystal

Principal magnetic susceptibilities of cupric acetate monohydrate single crystal between room temperature and 90°K have been measured, from which the magnitudes of the exchange integrals for two directions of ionic cluster have been directly deduced. It is seen that the exchange integral is isotropic and remains constant to a first approximation in the range of temperature of study. The variation in g -values is calculated with the help of the constant J -value, in good agreement with PMR findings.
A Theoretical Study of the Measurement Effectiveness of Flexilevel Tests

A flexilevel test is found to be inferior to a peaked conventional test for measuring examinees in the middle of the ability range, superior for examinees at the extremes. Throughout the entire range of ability, a flexilevel test is much superior to any conventional test that attempts to provide accurate measurement at both extremes.
Cloud condensation nuclei over the Arctic Ocean in early spring

Abstract Cloud condensation nucleus (CCN) spectral data are presented for the Arctic in spring, which considerably augment the existing meager CCN database for the Arctic. Concurrent measurements of sulfate mass suggest that men of the CCN were commonly not sulfate. Sulfate was more closely associated with particles below the CCN size range. Some measurements of the microphysical structure of Arctic status clouds are aim described.
Orbital angular momentum vertical-cavity surface-emitting lasers

Harnessing the orbital angular momentum (OAM) of light is an appealing approach to developing photonic technologies for future applications in optical communications and high-dimensional quantum key distribution (QKD) systems. An outstanding challenge to the widespread uptake of the OAM resource is its efficient generation. In this work we design a new device that can directly emit an OAM-carrying light beam from a low-cost semiconductor laser. By fabricating micro-scale spiral phase plates within the aperture of a vertical-cavity surface-emitting laser (VCSEL), the linearly polarized Gaussian beam emitted by the VCSEL is converted into a beam carrying specific OAM modes and their superposition states, with high efficiency and high beam quality. This new approach to OAM generation may be particularly useful in the field of OAM-based optical and quantum communications, especially for short-reach data interconnects and QKD.
Constructions of Non-Commutative Lp-Spaces with a Complex Parameter Arising from Modular Actions

For a von Neumann algebra ℳ and a weight φ on ℳ, we will construct a complex one-parameter family of non-commutative Lp-spaces by using Calderon's complex interpolation method. This is a simultaneous and complete extension of the construction of non-commutative Lp-spaces by H. Kosaki and M. Terp. Moreover, we will show that for each p, all the parametrized Lp-spaces are mutually isometrically isomorphic as Banach spaces via natural maps.
EGRET Observations of the Diffuse Gamma-Ray Emission from the Galactic Plane

The high-energy diffuse gamma-ray emission from the Galactic plane, |b| ≤ 10°, is studied using observations from the Energetic Gamma-Ray Experiment Telescope (EGRET) on the Compton Gamma-Ray Observatory. The spatial distribution of the diffuse emission has been determined for four broad energy ranges after removing the contribution from point sources detected with greater than 5 σ significance. The longitude and latitude distributions of the intensity, averaged over 4° latitude ranges and 10° longitude ranges, respectively, are shown for the four energy ranges. Spectra of the diffuse emission in 11 energy bands, covering the energy range 30 MeV to 30 GeV, were determined for 10° × 4° (l × b) bins after correcting for the finite EGRET angular resolution. The average spectrum from the direction of the inner Galaxy is shown for 29 energy bands, covering the energy range 30 MeV to 50 GeV. At latitudes |b| > 2°, corresponding to gamma rays emitted within about 3 kpc of the Sun, there is no significant variation in the spectra with Galactic longitude. Comparison of the spectra from the Galactic plane (|b| < 2°) reveals no significant variation with Galactic longitude below about 4 GeV, which suggests that the cosmic-ray electron to proton ratio does not vary significantly throughout the Galaxy. Above 4 GeV, however, there is weak (about 3 σ) evidence for variation of the Galactic plane (|b| < 2°) spectrum with longitude. The spectrum is softer in the direction of the outer Galaxy by about E compared to the spectrum from the inner Galaxy. This variation of the diffuse gamma-ray emission hints at a variation of the cosmic-ray proton spectrum with Galactic radius, which might be expected if cosmic rays are accelerated primarily in the inner Galaxy and then propagate to the outer Galaxy or if the high-energy cosmic rays are confined less well in the outer Galaxy. The spatial and spectral distributions of the diffuse emission are compared with a model calculation of this emission based on dynamic balance and realistic interstellar matter and photon distributions. The spatial comparison is used to establish the value of the molecular mass calibrating ratio N(H2)/WCO and the cosmic-ray/matter coupling scale r0, which are the only adjustable parameters of the model. Comparisons with the observations indicates N(H2)/WCO = (1.56 ± 0.05) × 1020 mol cm-2 (K km s-1)-1 and r0 = (1.76 ± 0.2) kpc. The spatial agreement between this model and the observation is very good. However, above about 1 GeV the integral intensity predicted by the model is about 60% less than the observed intensity. Although the explanation of this excess is unclear, uncertainties in the neutral pion production function or variations in the cosmic-ray spectrum with Galactic radius may partially account for the underprediction. A small medium-latitude (2° < |b| < 10°) excess in the direction of the inner Galaxy exists and may indicate that the low-energy photon density used in the model is too low.