Miracle-dz/UniFAR-FTUs huggingface dataset:
Engineering Subwavelength Nanoantennas in the Visible by Employing Resonant Anisotropic Nanospheroids

We analyze the engineering of subwavelength nanoantennas composed of anisotropic nanospheroids, for the development of photonic devices. Instead of using conventional isotropic dielectrics, we introduce resonant anisotropic nanoparticles, allowing for shifting Kerker condition points further inside the visible. To address this study, we construct a perturbation-based discrete eigenfunction method, for the electromagnetic scattering of a plane wave by a prolate or oblate uniaxial anisotropic spheroid. The method is fast and yields the solution for the bistatic radar and total scattering cross sections, which is valid for small eccentricities of the spheroid. The validity of this technique is verified by the alternative general purpose discrete dipole approximation method. We investigate the engineering of subwavelength nanoantennas due to material and geometry shaping, like the change of anisotropy type, anisotropy ratio, and deviation of the nanoantenna from sphericity.
On Constructing Confidence Intervals for a Standardized Mean Difference in Meta-analysis

Abstract Under the random effects model for meta-analysis, confidence intervals for the overall effect are typically constructed using quantiles of the standard normal distribution. We discuss confidence intervals based on both the standard normal distribution and the t-distribution, in conjunction with several methods of estimating the heterogeneity variance for a standardized mean difference, and we compare the empirical coverage probabilities of the intervals using simulation. The coverage probabilities of intervals based on an approximate t-statistic are higher than the coverage probabilities for the standard normal intervals, and are very close to the specified confidence level even for small meta-analysis sample size. Moreover, intervals based on the approximate t-statistic appear relatively robust to different methods of estimating the heterogeneity variance, unlike the normal intervals. Thus, we conclude that confidence intervals based on the t-statistic are superior to the standard normal confidence intervals for a standardized mean difference, and should be used by practitioners in place of the normal intervals.
Fixed width confidence intervals based on bootstrap procedures

Let Tn be an estimate of the parameter θ and for a fixed d let Pn* be the bootstrap estimate of the probability that θ is included in the interval (Tn - d,Tn +d). Let N* be the first n such that P* n ≥ 1-α with 0<α<1. If Tn is the sample mean, then the asymptotic behaviour of N* as d↓0 is the same as that of the well known Chow Robbins procedure. Monte Carlo calculations show that these procedures are also very similar non asymptotically. If Tn is the median, the asymptotic behaviour of N* is the same as that of the procedure of Geertsema but Monte Carlo calculations in this case favours the bootstrap procedure.
Mesoscale Analysis of Heavy Rainfall Episodes from SoWMEX/TiMREX

AbstractThe authors analyze the mesoscale structure accompanying two multiday periods of heavy rainfall during the Southwest Monsoon Experiment and the Terrain-Induced Mesoscale Rainfall Experiment conducted over and near Taiwan during May and June 2008. Each period is about 5–6 days long with episodic heavy rainfall events within. These events are shown to correspond primarily to periods when well-defined frontal boundaries are established near the coast. The boundaries are typically 1 km deep or less and feature contrasts of virtual temperature of only 2°–3°C. Yet, owing to the extremely moist condition of the upstream conditionally unstable air, these boundaries appear to exert a profound influence on convection initiation or intensification near the coast. Furthermore, the boundaries, once established, are long lived, possibly reinforced through cool downdrafts and prolonged by the absence of diurnal heating over land in generally cloudy conditions. These boundaries are linked phenomenologically with .
A Determination of the Ampere

The ampere has been determined by means of the Ayrton-Jones current balance of the National Physical Laboratory. The result shows that the unit of current maintained at the Laboratory by standard resistors and standard cells exceeds the ampere by 15 in 106, with a probable error of 4 in 106. From this figure and a previous measurement of the precessional frequency of protons, it is deduced that the gyromagnetic ratio of the proton in water, uncorrected for diamagnetism, is 2.675 13 × 108 C/kg with a total probable error of 5 in 106.
Integral variable-structure control with variable-structure sliding dynamics for antireset windup

This paper proposes a scheme of integral variable-structure control with variable-structure sliding dynamics, referred to as VSSD-IVSC, based on the framework of the so-called global sliding-mode control (GSMC) technique. Previous GSMC schemes encompass the robust eigenvalue-assignment GSMC (REA-GSMC) and the integral variable-structure control (IVSC). All GSMC schemes feature the insurance of existence of a sliding mode throughout an entire response for performance robustness. It is shown in this paper that both REA-GSMC and IVSC lead to the same robust tracking performance in theory. In practical implementations the IVSC has better steady-state error characteristics than the REA-GSMC. However, due to control saturation, the IVSC may suffer from the integrator windup problem common to control methods with integral compensation. The VSSD-IVSC scheme is proposed to combine the REA-GSMC and the IVSC using the GSMC framework, and it has variable-structure sliding dynamics for antireset windup. Experiments were conducted on a two-link direct-drive manipulator to demonstrate the effectiveness of the proposed scheme.
Aerodynamic Flow Control over an Unconventional Airfoil Using Synthetic Jet Actuators

Control of flow separation on an unconventional symmetric airfoil using synthetic (zero net mass flux) jet actuators is investigated in a series of wind tunnel tests. The symmetric airfoil comprises the aft portion of a NACA four-digit series airfoil and a leading edge section that is one-half of a round cylinder. The experiments are conducted over a range of Reynolds numbers between 3.1 × 10 5 and 7.25 × 10 5 . In this range, the flow separates near the leading edge at angles of attack exceeding 5 deg. When synthetic jet control is applied near the leading edge, upstream of the separation point, the separated flow reattaches completely for angles of attack up to 17.5 deg and partially for higher angles of attack. The effect of the actuation frequency, actuator location, and momentum coefficient is investigated for different angles of attack. The momentum coefficient required to reattach the separated flow decreases as the actuators are placed closer to the separation point. In some cases, reattachment is also achieved when the actuators are placed downstream of the stagnation point on the pressure side of the airfoil
Quantum Noise Suppression in Two Dimensional Photonic Crystal Fibers

In this paper we present the basic theory of nonlinear photonic crystal fibers (PCFs) with a focus on theoretical aspects of generating squeezed light using Kerr effect. The FDTD method is employed to study the guided modes of em field propagation in PCF. The degree of squeezing is determined using correlations function corresponding to the fields of light. It is shown that noise in a squeezed light is reduced to about 24% below the minimum noise observed in coherent light.
Numerical and Experimental Study on Jet Trajectories and Mixing Behavior of Venturi-Jet Mixer

An investigation of the jet trajectories and mixing behavior of venturi-jet mixers, in which turbulent jet injects fluid at an arbitrary angle to mix incompressible fluids, is described in this paper. Numerical results of an incompressible cross flow-jet mixing in venturi-jet mixers are presented and validated against experimental results. Jet trajectories, concentration decay of tracer jet, spatial unmixedness, and mixing length are computed for a range of injection angles (45 deg≤θ o ≤135 deg). Twenty-five cases are studied with five different initial injection angles, each with five different jet momentum ratios. As an example of practical insights that can be gained from such detailed analysis, the resulting flow field is used to obtain an equation,for trajectory and tracer concentration in the mixer. The penetration of jet scales with the third root of the jet-to-mainstream momentum ratio and that of with square root of downstream distance. The decay of mean concentration scales with the inverse of axial distance and with the negative root of injection angle. The results show a consistency in the experimental data and simulation has provided a good insight into the flow details and has paved the way in optimization of the geometry based on jet injection angle to get a good mixing efficiency.
Modelling and controlling one-degree-of-freedom impacts

The problem of modelling and controlling a one-degree-of-freedom impact between two bodies is considered. Basic equations describing the motion of the bodies involved in the collision are derived under conditions of noncontact and contact. A control scheme is proposed on the basis of an observer that is able to asymptotically estimate the impact-induced forces and to allow their asymptotic compensation when the two bodies are in contact. A simulation test is included.
Optimal iterative algorithms in Gabor analysis

Gabor expansions of discrete signals and images have a wide range of applications in signal analysis and pattern recognition. It is well known that the difficulty in expanding a 1-D or a 2-D signal into a Gabor series is the non-orthogonality of the building blocks, which are time-frequency shifted versions (along some lattice in the TF-plane) of a, given Gabor atom. The theory of frames (Gabor or Weyl-Heisenberg frames) has reached fame as the appropriate tool for resolving the problem. In particular, the dual frame turns out to be again a Gabor frame with respect to the same lattice, and its generating function is called the dual Gabor atom g/spl tilde/. It is obtained by applying the inverse of the frame operator S to the original frame (or just the Gabor atom), i.e. g/spl tilde/= S/sup -1/g. There is also another important use for the dual Gabor window. Given the sampled STFT (short time or sliding window Fourier transform) of some signal x with respect to the window g over the same lattice it is possible to recover the signal x using a simple Shannon-type reconstruction formula. We present some basic ideas behind a new family of iterative algorithms for determining the dual Gabor atom in the finite (discrete and periodic) case. They are mainly based on the conjugate gradient methods in combination with structural properties of the Gabor frame operator. <<ETX>>
VECTOR DIFFRACTION OF A GRATING WITH CONFORMAL THIN FILMS

Vector diffraction theory is appropriate whenever the dimensions of the diffracting structures are comparable with the wavelength of the incident light in order to account correctly for polarization effects. If a periodic groove or pit array is coated with a conformal thin-film stack, the diffracting properties of the substrate may be substantially altered. A computationally efficient vector diffraction model for conformal thin films on a biaxial grating is described that does not require coordinate transformations of Maxwell’s equations. Calculated results are compared with other published work on diffraction anomalies and with experimental measurements on a rewritable optical disk.
Light scattering by ice clouds in the visible and infrared - A theoretical study.

Abstract Computations of the intensity and linear polarization for single scattering by ice clouds have been made based on the assumption that the particles in ice clouds can be approximated by long circular cylinders which are allowed to be polydispersive as well as arbitrarily oriented in space. The results of two models of optically thin ice clouds are presented and compared with those for polydisperse ice spheres. The two models for ice cylinders are assumed to be either uniformly or randomly oriented in a horizontal plane. Four different wavelengths, 0.7, 3, 3.5 and 6.05 μ, are employed in the light scattering computations. It is found that, compared to ice spheres, long ice cylinders scatter more light in the region with scattering angles near 90°, at the expense of scattering in both the forward and backward directions. The glory and cloudbows, which occur in light scattered by spherical particles, are either lost (the glory) or largely reduced and distorted (the cloudbows) in the case of cylinders.
Quantum size effect in the photoluminescence properties of p-type semiconducting transparent CuAlO2 nanoparticles

Photoluminescence properties of CuAlO2 nanoparticles, deposited by a cost-effective direct current sputtering technique, have been studied. The nanoparticles show room-temperature photoluminescence peaks of near-band-edge emission due to recombination of free excitons. A blue-shift in the emission peaks as a decreasing function of the nanoparticle sizes is observed, which is attributed to the quantum confinement effect within the CuAlO2 nanoparticles. Theoretical calculations of bandgap enhancement values are found to be matching fairly well with that of the experimentally obtained values, confirming the existence of the quantum size effect within the nanomaterial. Approximate calculations show that the confinement effect falls within moderate-to-weak confinement regime. X-ray diffraction and electron microscopic measurements confirm the proper phase formation and nanocrystalline structure of the as-deposited nanoparticles. The room-temperature and size-dependent photoluminescence properties of this nanom.
Normal momentum transfer on ideal crystalline surfaces

I a previous Note the authors reported on a molecular collisional analysis of tangential momentum transport from a flowing gas to a solid surface. The surface was taken to be macroscopically smooth and flat, i.e., monocrystalline on a molecular scale, so that comparison with experimental data on tangential momentum transfer rates could be used to estimate the importance of roughness of real surfaces. The gas-surface system was represented by a simple molecular model, and calculations were made of the tangential momentum transfer coefficient <rt as a function of the dimensionless gas velocity and the length parameter of the molecular interaction potential. The trends in the calculated results for <jt generally agreed with observation, but the calculated magnitudes were somewhat lower than typical measured values, as would be expected if the effect of surface roughness (polycry stallinity) were significant. The purpose of this Note is to report values of normal momentum transfer coefficients calculated for the same gassurface model. In this case the model is clearly of more questionable validity, for reasons to be described below. The results should therefore be viewed as tentative until they can be compared with experiment or until studies with a more accurate surface model have been made. Consider the free-molecule flow of a rarefied gas along a stationary infinite flat plate whose surface is the plane y = 0. The gas velocity u = xu(y,t) is in the x direction parallel to the plate and is steady and uniform far from the plate; that is, lim u(y,t) = U, a constant. If we let/(c,? /,0 be the distribu-
Direct Imaging of Circumstellar Disks in the Orion Nebula

We present observations of the Orion Nebula made with the Hubble Space Telescope in which a number of stars are seen surrounded by dark silhouettes seen projected against the bright background H II region. We find a variety of morphologies, all consistent with thin circumstellar disks spanning a range of diameters (50 to 1000 AU) and inclination angles (0 to > 80 degrees). The silhouette intensity profiles cannot be fit by standard disk models in which the surface density follows a radial power law with an exponent in the range −0.75 to −1.5. Rather, the data are best fit by opaque inner disks with exponential edges, and we discuss possible physical origins of this apparent truncation. Masses in the range 6 × l0 26 −4 × 10 30 g ( i.e ., up to 0.002 M ⊙ ) are determined for the disks by assuming that the faint light measured from them is background light transmitted through the disk. However, these are strict lower limits on the true disk masses, as most of this light can be accounted for by PSF blurring and scattering in the HST optical train; the present observations are in fact consistent with completely opaque disks. Central stars are seen directly in five of the silhouettes, while the presence of a star is inferred in the sixth, where small reflection nebulae are seen above and below the plane of the near edge-on disk. Optical and near-infrared stellar photometry is consistent with young (~ 1 Myr) low-mass (0.3−1.5 M ⊙ ) stars, with several showing evidence for excess near-infrared emission from the disk inner edge. These direct imaging observations are discussed in the wider context of circumstellar disks in the Orion Nebula and Trapezium Cluster, additionally revealed as compact ionized nebulae (so-called “proplyds”) in the vicinity of the central OB stars, and via infrared (>2 µ m) excesses in stellar photometry. Overall, disks are found to be common in the cluster (>50% of all stars), implying that they can survive the rigours of life near massive stars.
Photoinduced products from cold coronene clusters. A route to hydrocarbonated nanograins

Free cold pure coronene clusters have been formed in a gas aggregation source and irradiated with excimer laser pulses. Analysis of the photoproducts thanks to a reflectron time-of-flight mass spectrometer showed that new ionic compounds are formed. These species may include Polycyclic Aromatic Hydrocarbons (PAHs) larger than coronene, PAH-coronene clusters, as well as coronene clusters branched with unsaturated aliphatic chains. The relevance of these results in the context of interstellar medium chemistry, and in particular the carriers of the so-called aromatic infrared emission bands (AIBs), is discussed.
Microwave Backscatter and Extinction by Soft Ice Spheres and Complex Snow Aggregates

Abstract Coupled-dipole approximation (CDA) calculations of microwave extinction and radar backscatter are presented for nonhomogeneous (soft) ice spheres and for quasi-realistic aggregates of elementary ice crystal forms, including both simple needles and real dendrites. Frequencies considered include selections from the Dual-Frequency Precipitation Radar (DPR; 13.4 and 35.6 GHz) and the Global Precipitation Measurement (GPM) Microwave Imager (GMI; 18.7, 36.5, and 89.0 GHz), both slated for orbit on the GPM mission. The computational method is first validated against Mie theory using dipole structures representing solid ice spheres as well as stochastically generated “soft” ice spheres of variable ice–air ratio. Neither the traditional Bruggeman nor Maxwell Garnett dielectric mixing formula is found to correctly predict the full range of CDA results for soft spheres. However, an excellent fit is found using the generalized mixing rule of Sihvola with ν = 0.85. The suitability of the soft-sphere approxima.
Estimating |α – p / q|

Abstract An estimate for q2|α – p/;q| is obtained by considering the relation between the continued fractions for α and p / q. This leads to an extension of the standard result “q2|α – p/q| < 1 imples that for some n, p/q = (ipn + pn-1) / (iqn + qn-1) where i = 0, 1 or an+1 −1”.
Visual target tracking in the presence of unknown observer motion

Much attention has been given to the visual tracking problem due to its obvious uses in military surveillance. However, visual tracking is complicated by the presence of motion of the observer in addition to the target motion, especially when the image changes caused by the observer motion are large compared to those caused by the target motion. A method is presented for estimating the motion of the observer based on image registration techniques and Kalman filtering. With the effects of the observer motion removed, an additional phase is implemented to track individual targets. This method is demonstrated on an image stream from a buoy-mounted or periscope-mounted camera, where large inter-frame displacements are present due to the wave action on the camera. This system has been shown to be effective at tracking and predicting the global position of a planar vehicle (boat) being observed from a single, out-of-plane camera. Finally, the tracking system has been extended to a multi-target scenario.
X-ray observations of the VELA pulsar: Statistics and spectrum

The Vela pulsar was observed in the range 2-60 keV by the GSFC proportional counter experiment onboard OSO-8 with temporal resolution sufficient to make possible a sensitive search for pulsed X-rays at the radio pulsar period. A statistical analysis yielded 8 per cent as the 3 sigma upper limit on the pulsed fraction. The energy spectrum is fit well by a structureless power law with number index 2.21 + or - 0.2 and absorption by a hydrogen column density of N sub H equals 2.9 + or - 2.0 times ten to the twenty-second power per sq.cm.
A Modified Hall-Padmanabhan Test for the Homogeneity of Scales

We consider a simple adaptive test for the homogeneity of scales due to Hall and Padmanabhan (1997) which is based on the ratio of adaptively trimmed sample variances. We develop a modification of this test that has the form of a combined bootstrap test and that is obtained within the nonparametric combination of dependent tests framework (Pesarin, 2001). We considered other approaches for the combination of tests concluding that the Liptak method is the most suitable one for the problem at hand. We compare the modified test with the original one in terms of robustness of significance level and power in a simulation study which considers distributions that range from symmetric to skewed and from light to heavy tailed ones. We show that the modified test is more powerful than the original one under heavier than normal tailed and very skewed distributions. A practical application to detect difference in scale of energy intake of lactating and non pregnant and not lactating women is presented.
Quaternary elevation change of the Gulf of Corinth in central Greece

Dramatic elevation changes have occurred since early Pleistocene time in and around the Gulf of Corinth sedimentary basin in central Greece, which is actively extending at a maximum rate of ca. 2 mm a-1 . Shoreline deposits younger than 1 million years are found at up to ca. 1200 m elevation south of the Gulf, with sediment from an older Plio-Pleistocene basin above 1750 m. The Gulf floor, in the hanging-wall of normal faults along its southern coast, has subsided up to ca. 1650 m on the same timescale. However, other hanging-wall localities such as the Corinth isthmus - east of the Gulf - have uplifted instead. During the past million years the Gulf has alternated between marine and lacustrine environments in response to glacially induced sea-level variations. This study establishes its chronology of marine and lacustrine terraces for the past half million years, allowing lateral variations in uplift to be investigated. To explain the observed elevation changes, it is suggested that ca. 0.9 million years ago the previously lacustrine Gulf became flooded by ca. 80 m during an interglacial marine highstand. The resulting ca. 0.8 MPa increase in lithostatic pressure at the base of the brittle upper crust caused southward lower-crustal flow to beneath the older Plio-Pleistocene basin. Isostatic adjustment uplifted this basin, creating unstable topography that enabled rapid erosion. This lower-crustal flow, which since been maintained by the sediment load in the Gulf that results from this erosion, also causes the hanging-wall uplift of the Corinth isthmus and other ‘anomalous’ localities. The Gulf of Corinth is thus an important case study locality for revealing the existence of lower-crustal flow during continental extension.