Miracle-dz/UniFAR-FTUs huggingface dataset:
SEASONAL CHANGES IN TITAN'S SURFACE TEMPERATURES

Seasonal changes in Titan's surface brightness temperatures have been observed by Cassini in the thermal infrared. The Composite Infrared Spectrometer measured surface radiances at 19 μm in two time periods: one in late northern winter (LNW; Ls = 335°) and another centered on northern spring equinox (NSE; Ls = 0°). In both periods we constructed pole-to-pole maps of zonally averaged brightness temperatures corrected for effects of the atmosphere. Between LNW and NSE a shift occurred in the temperature distribution, characterized by a warming of ∼0.5 K in the north and a cooling by about the same amount in the south. At equinox the polar surface temperatures were both near 91 K and the equator was at 93.4 K. We measured a seasonal lag of ΔLS ∼ 9° in the meridional surface temperature distribution, consistent with the post-equinox results of Voyager 1 as well as with predictions from general circulation modeling. A slightly elevated temperature is observed at 65° S in the relatively cloud-free zone between the mid-latitude and southern cloud regions.
Ultramicroindentation apparatus for the mechanical characterization of thin films

An apparatus is described which is suitable for the mechanical characterization of all kinds of extremely thin films by indentation experiments at very low loads. The penetration depth can be measured as a function of time or load with a resolution of 5 nm. The indentor force can be varied from 10 μN to 5 mN. On the basis of some examples it is demonstrated that the instrument is applicable for ultramicrohardness measurements on metal films as well as for the determination of the viscoelastic properties of polymer coatings. Moreover, it is shown that the apparatus can be used for surface profilometry and ultramicroscratching experiments on relatively soft layers.
Modification of the Boundary Layer over the South China Sea during a Winter MONEX Cold Surge Event

Abstract Aircraft dropwindsonde and conventional sounding data have been used to document the boundary layer structure over the South China Sea during the period of a 3-day moderate cold surge that occurred during the December 1918 Winter Monsoon Experiment (Winter MONEX). Throughout the cold surge event, equatorward deepening of the cumulus layer is observed over the northern South China Sea (to the south of a coastal cloud-free region) as cold air streaming of the coast encounter substantial surface, sensible and latent heat fluxes. Following the onset of the cold surge, the cumulus-layer depth increases over the central South China Sea. However, this depth decreases over the northern South China Sea at a distance of 200–300 km from the China coast. The depth and strength of the cumulus (or subsidence) inversion are greatest new the China coast (∼600–700 m, 4°–6°C) and weaken toward the central South China Sea (∼200 m, 1°C), whew they eventually become undetectable. Possible explanations for the observe.
D-Optimum Designs for Heteroscedastic Linear Models

Abstract The methods of optimum experimental design are applied to models in which the variance, as well as the mean, is a parametric function of explanatory variables. Extensions to standard optimality theory lead to designs when the parameters of both the mean and the variance functions, or the parameters of only one function, are of interest. The theory also applies whether the mean and variance are functions of the same variables or of different variables, although the mathematical foundations differ. The example studied is a second-order two-factor response surface for the mean with a parametric nonlinear variance function. The theory is used both for constructing designs and for checking optimality. A major potential for application is to experimental design in off-line quality control.
Sample size requirements to test the equality of raters' precision

Exact and approximate methods are developed to calculate the required number of subjects n in a repeatability study, where repeatability is measured by the precision of measurements made by a rater. The exact method is based on power calculations under the non-null distribution of the multiple coefficient of determination, which requires intensive numerical computation. The approximate method is based on predictions from families of non-linear curves fitted by the method of least squares.
Generalized Monte Carlo significance tests

SUMMARY Simple Monte Carlo significance testing has many applications, particularly in the preliminary analysis of spatial data. The method requires the value of the test statistic to be ranked among a random sample of values generated according to the null hypothesis. However, there are situations in which a sample of values can only be conveniently generated using a Markov chain, initiated by the observed data, so that independence is violated. This paper describes two methods that overcome the problem of dependence and allow exact tests to be carried out. The methods are applied to the Rasch model, to the finite lattice Ising model and to the testing of association between spatial processes. Power is discussed in a simple case.
Leftover parts in the biomimetic agenda

Biological systems have proven a rich source of inspiration for engineered systems with highly desirable properties, such as distribution, decentralization, and dynamic adaptation. However, the inspiration has been selective. Certain features, such as interaction through a shared environment, are very widely imitated. Others are less frequently exploited. These include the process of speciation, courtship signals, and death. Based on twenty-five years of experience in engineering biomimetic systems for real-world applications, this paper considers the potential contributions of some of these less-used mechanisms to solving real-world problems.
Development of New Mode-Superposition Technique for Truncating Lower- and/or Higher-Frequency Modes : Application of Eigenmode Sensitivity Analysis for Systems with Repeated Eigenvalues

In this paper, the development of a modal sensitivity analysis method is described for a system with repeated eigenvalues. It is shown that the new algorithm proposed by the authors has much better computational accuracy than the method proposed by S. H. Chen and H. H. Pan, and this method is simpler in terms of calculations than Ojalvo's and Dailey's methods, which was presented recently. The new method can also be extended to a coupled acoustic-structural system with repeated eigenvalues, and thus can be applied to vibration-noise reduction problems.
Heat Transfer Predictions for Two Turbine Nozzle Geometries at High Reynolds and Mach Numbers

Predictions of turbine vane and endwall heat transfer and pressure distributions are compared with experimental measurements for two vane geometries. The differences in geometries were due to differences in the hub profile, and both geometries were derived from the design of a high rim speed turbine (HRST). The experiments were conducted in the Isentropic Light Piston Facility (ILPF) at Pyestock at a Reynolds number of 5.3 x 10 6 , a Mach number of 1.2, and a wall-to-gas temperature ratio of 0.66. Predictions are given for two different steady-state three-dimensional Navier-Stokes computational analyses. C-type meshes were used, and algebraic models were employed to calculate the turbulent eddy viscosity. The effects of different turbulence modeling assumptions on the predicted results are examined. Comparisons are also given between predicted and measured total pressure distributions behind the vane. The combination of realistic engine geometries and flow conditions proved to be quite demanding in terms of the convergence of the CFD solutions. An appropriate method of grid generation, which resulted in consistently converged CFD solutions, was identified.
Defect characterization of 4H-SiC wafers for power electronic device applications

Silicon carbide is a semiconductor of choice for the fabrication of high-power, high-temperature and high-frequency electronic devices. Nevertheless, such a material still presents many problems as regards the crystallographic quality and the presence of defects, which influence the device performance. We have investigated 4H-SiC wafers and 4H-SiC epitaxial layers by microscopy and structural techniques in order to obtain information about the defect morphology. The goal of this analysis will be to correlate them with the electrical properties of SiC for power electronic device applications.
Analysis and experimental demonstration of adaptive optics based on the modal control optimization

A modal control optimization method for adaptive optics on the tempo-spatial domain is presented. The spatial modes of the adaptive optics system can be obtained by the singular value decomposition of the response function matrix of the adaptive optics system. The number of correction modes is determined dynamically by the root mean square estimation of the residual aberration after the correction with different number of modes. A Smith compensator is designed to reduce the time delay effect on the closed-loop system. The modal optimization method is experimentally verified by compensating phase distortion produced by artificial atmospheric turbulence in laboratory. Experimental results show that the correction capability of the adaptive optics system can be greatly improved in comparison to that of the generic modal gain integrator approach with the fixed number of correction modes. The modal control optimization method is an attractive and practical alternative to adaptive optics control.
Carbon nanotube network evolution during deformation of PVDF-MWNT nanocomposites

The emergence of novel electronic systems and their requirements have necessitated the evolution of new material classes. The traditional electronic semiconductors and components are shifting from silicon based substrates to polymers and other organic compounds. Sensor components are no exceptions, where compliant polymeric materials offer the possibility of flexible electronics. This paper examines the fabrication and characterization of piezoresistive nanocomposites for pressure sensing applications. The matrix material employed was Polyvinylidene Fluoride (PVDF). The PVDF phase was reinforced with conductive particles, in order to form a conductive filler network throughout the nanocomposite. Multiwall carbon nanotubes (MWNT) were selected as conductive particles to form the networks. The composites were prepared by melt mixing the PVDF and conductive particles in compositions ranging from 0.25 to 10 wt% conductive particle in PVDF. The dielectric permittivity and electrical conductivity of the composites was characterized and the electrical percolation behavior of PVDF nanocomposites fitted to the statistical percolation model. Scanning electron was employed to understand the morphology of the filler networks in the PVDF nanocomposites. Quasi-static piezoresistance of the nanocomposites was characterized using a custom-built force-resistance measurement setup under compressive loading conditions.
Investigating the Accuracy of Three Estimation Methods for Regression Discontinuity Design

Regression discontinuity design is an alternative to randomized experiments to make causal inference when random assignment is not possible. This article first presents the formal identification and estimation of regression discontinuity treatment effects in the framework of Rubin's causal model, followed by a thorough literature review of three major methods for estimating regression discontinuity effects. The authors conducted a Monte Carlo simulation to compare the accuracy of 3 estimation methods and evaluate the effects of sample sizes, cutoff score locations, and distribution assumptions on the accuracy of parameter estimates. Although all 3 methods can produce reasonably accurate parameter estimates under various manipulated data conditions, extreme cutoff scores tend to introduce large parameter estimate biases when the variance of the outcome variable differs across groups. Implications and directions for further research are discussed.
A broadband omnidirectional absorber based on a hetero-structure composed of a collision plasma and a ternary plasma Bragg mirror

A broadband omnidirectional absorber which is realized by heterostructures containing a collision plasma layer and a ternary plasma Bragg mirror is theoretically investigated. A collision plasma layer and an appropriate dielectric layer are put on the top of the ternary plasma photonic crystals to obtain a broadband omnidirectional absorption. It is shown to absorb roughly 70% of all available electromagnetic wave in a relative omnidirectional absorption band width 0.58 GHz with plasma width 3 mm in PCs. The band edges are impacted by the range of reflection band gap and the absorption range for transverse magnetic (TM) wave decreases at large incidence. Compared with some previous designs, our proposed structure has a relative flatter total absorption spectrum over a broad frequency range in microwave. This kind of hererostructures offer additional opportunities to design novel optoelectronic devices.
Energy and mechanical properties of single-walled carbon nanotubes predicted using the higher order Cauchy-Born rule

Based on the higher order Cauchy-Born rule, a continuum-based constitutive model, which taking the interatomic potentials and atomic microstructure of carbon nanotubes into consideration, is presented for the analysis of the mechanical properties of carbon nanotubes. With the use of Tersoff-Brenner potential, the influences of the potential parameters, tube diameters, chirality and the inner displacement on the energies, the axial Young’s moduli, the circular elastic moduli of graphite and single-walled carbon nanotubes as well as the bending stiffness of SWNT are investigated. The results obtained are in good agreement with that of molecular dynamics.
Recursive wavelet filters for video coding

Recursive wavelet filters and an alternative algorithm for implementing wavelet transform are presented in this paper. The recursive filters use previously calculated (past) wavelet coefficients as inputs to calculate the current wavelet coefficient, and provide the same transform results as convolutional FIR and lifting wavelet filters. The coefficients of the recursive filters are derived from those of conventional FIR wavelet filters. The wavelet transform with recursive filters requires a smaller amount of memory and is easy to implement in hardware. Another important advantage of the recursive filters is that perfect reconstruction can be easily achieved using recursive wavelet filters if a sequence of pixels to be transformed is extended by boundary pixel repetition. Boundary pixel repetition can be more efficient than the widely used method of symmetric extension for image and video coding.
Microphysical Characteristics of Three Anvils Sampled during the Central Equatorial Pacific Experiment

Abstract In situ microphysical measurements of three anvils were made 17 March, 1 April, and 4 April 1993 during the Central Equatorial Pacific Experiment for several constant altitude penetrations, in the same direction or opposite the ambient wind, from 7 to 14 km. Ice water contents (IWCs), derived from an optical array probe, increased downward in the anvil; concentrations also increased, but not as quickly. Median mass dimensions, defined as the ice crystal maximum dimension below which half of the mass is contained, increased from averages of less than 0.1 mm near the tops to averages of about 0.5 mm near the bases. Substantial variations in cloud parameters occurred in the horizontal direction as well, with larger IWCs and concentrations closer to the convective core and its remnants. Small crystals were measured and categorized according to their shapes with the Video Ice Particle Sampler, which detects particles with dimensions greater than 5 µm. For small IWCs, especially prevalent at cloud tops.
Analysis of skin moles from optical spectropolarimetric images

Imaging of the skin to detect the signs of cancer becomes very common these days. A new noninvasive skin imaging method developed recently gives an informative image data about the skin tissue by collecting scattered polarized light reflected from a mole area. This method scans the polarization states by continuously rotating a linearly polarized light incident on the lesion and collecting the reflected sequence of images with a CCD camera. The two main wavelengths that were used in the study were 520nm (penetration is about 100μm) and 700nm (penetration is about 200μm). Methods developed in the past to diagnose suspicious moles were implemented to visual images. However, such methods cannot be employed directly to our images because of their different properties. In this paper, we analyze skin moles obtained from this system for the purpose of distinguishing cancerous from benign moles. First, we pre-process the mole image by de-noising, contrast enhancement and intensity-based segmentation of the mole region. Then, an automatic examination of the polarized images is carried out according to characteristics such as their symmetry, cross-image local contrasts and large-scale homogeneity.
Progressive lightning IV-The discharge mechanism

In three previous papers (Schonland and Collens 1934; Schonland, Malan and Collens 1935; Malan and Collens 1937) in this series the writer and his collaborators have described the results of a study of the lightning discharge to ground by means of the Boys and other cameras. During the last two years these studies have been continued with improved instruments, and the electrical changes taking place during the discharge have been examined by means of a cathode-ray oscillograph. An account of some important results obtained by the latter method has recently been published by Appleton and Chapman (1937). These are confirmed and extended by our own later investigations. With this fuller information it is now possible to put forward some deductions as to the discharge mechanism.
Bayesian image reconstruction from partial image and spectral amplitude data

We address a problem of reconstruction of a periodic image from information in image space and Fourier space. The real space information consists of knowledge of part of the image, while the Fourier space information is data in the form of sums of the squares of the amplitudes of sets of particular Fourier coefficients of the image. Such a problem occurs in the determination of polymer structures from x-ray fiber diffraction data. We present a Bayesian approach to this problem, incorporating a priori model for the image based on the structure being made up of 'atoms'. The Bayesian minimum mean-square-error estimate for the missing part of the image is derived. Currently used heuristic estimates are the maxima of certain posterior densities. Simulations are performed for varying amounts of real and Fourier space information to assess the performance of the different estimators. The performance of the minimum mean- square-error estimate is superior to that of the other estimates.
The Flexural Response of a Submerged Solid to a Pulsating Gas Bubble

A bubble in a liquid pulsates and generates a changing pressure field. This reacts with a submerged flexible solid and induces elastic motions. Equations are derived which show how the vibration modes and frequencies of the solid are modified by the presence of the water, and how each mode is excited by the bubble pulsation. The generalized force for each mode is proportional to the volume acceleration of the bubble. The initial analysis presupposes incompressive flow, but it is shown that the results remain applicable if the duration of any compressive phase is small compared to the pulsation period of the bubble and the vibration period of the solid.
Nonlinear splitting of fast particle driven waves in a plasma: observation and theory

The measured spectra of fast particle driven Alfv{acute e}n eigenmodes in the JET tokamak plasma are interpreted on the basis of a nonlinear model of near-threshold kinetic instabilities. The observed mode splitting is a manifestation of the general nonlinear phenomena due to the combination of resonant wave-particle interaction and collisionlike relaxation of the resonant particles. The instability growth rate and the effective collision frequency of the resonant particles are determined. {copyright} {ital 1998} {ital The American Physical Society }
An efficient algorithm for a class of equality-constrained optimization problems

The paper is concerned with computing a solution ∗of the nonlinear optimization problem subject to fixed. An auxiliary system of nonlinear equations is constructed the solution z∗of which contains ∗Utilizing the special structure of F(z)=0 an efficient algorithm for solving the optimization problem, is proposed, and assertions about the convergence of the generated sequences are shown.
Numerical simulations of turbulent trapping in the weak beam–plasma instability

Numerical simulations of the weak beam–plasma instability were done in the turbulent regime where small‐scale trapping is a dominant feature of the instability, a regime with behavior not predicted by quasilinear theory. It occurs when the trapping frequency ν=(k2D)1/3 is larger than the growth rate γk of the instability. The results of the simulations were compared with those of a specific model of the turbulence, the so‐called ‘‘turbulent trapping’’ model, which gives precise formulas for the particle correlation functions, and predicts a growth rate well enhanced over the quasilinear value. It was found that the model gives accurate predictions for the correlation functions, and thus provides a good description of the turbulent structure of phase space. On the other hand, while growth rates were enhanced over the quasilinear values, the enhancements observed are smaller than expected from the quantitative predictions of the model.
Optimum control voltage design for constrained static shape control of piezoelectric structures

Design optimization of control voltage distribution for constrained static shape control of structures using piezoelectric actuators is investigated. Two cases are studied. In the first case, a scheme is developed to find the optimal control voltage distribution minimizing the square error between the desired and actuated shapes subject to a given control electric energy. The optimal control voltage constrained by control energy can be found after solving an algebraic equation in terms of the Lagrangian multiplier. An alternative form for this algebraic equation is derived by taking advantage of an eigenvalue problem of a real symmetrical matrix, which significantly reduces the computational cost for finding its roots. A procedure for finding the optimal control energy is also given. In the second case, a process of seeking the control voltage distribution with least control energy for any given square error tolerance between the actuated and desired shapes is presented. Finally, illustrative examples for the constrained shape control of thin plates are given to demonstrate the presented methods.