Miracle-dz/UniFAR-FTUs huggingface dataset:
Local electrical dissipation imaged by scanning force microscopy

The low internal damping of micromachined monolithic silicon levers with integrated probe tip has been exploited to detect nonconservative components in the interaction forces between the probe tip and sample. This is accomplished by monitoring the mechanical Q while scanning the surface. The gap width was controlled by keeping the lever’s resonance frequency detuning, caused by the gradient of the force between tip and surface, fixed to a preset value. Nonconservative components are present even in Coulomb attraction since, whenever a voltage is applied between tip and substrate, currents are induced by the lever’s oscillation leading to Joule dissipation of energy at a rate that depends on the local conductivity. Strong damping contrast was observed in layered GaAs/AlGaAs semiconductor heterostructures. It depended on the type of material, dopant concentration, illumination, and the applied voltage. Damping variations were resolved over distances of less than 20 nm.
Contextual object understanding through geospatial analysis and reasoning (COUGAR)

Military operations in urban areas often require detailed knowledge of the location and identity of commonly occurring objects and spatial features. The ability to rapidly acquire and reason over urban scenes is critically important to such tasks as mission and route planning, visibility prediction, communications simulation, target recognition, and inference of higher-level form and function. Under DARPA's Urban Reasoning and Geospatial ExploitatioN Technology (URGENT) Program, the BAE Systems team has developed a system that combines a suite of complementary feature extraction and matching algorithms with higher-level inference and contextual reasoning to detect, segment, and classify urban entities of interest in a fully automated fashion. Our system operates solely on colored 3D point clouds, and considers object categories with a wide range of specificity (fire hydrants, windows, parking lots), scale (street lights, roads, buildings, forests), and shape (compact shapes, extended regions, terrain). As no single method can recognize the diverse set of categories under consideration, we have integrated multiple state-of-the-art technologies that couple hierarchical associative reasoning with robust computer vision and machine learning techniques. Our solution leverages contextual cues and evidence propagation from features to objects to scenes in order to exploit the combined descriptive power of 3D shape, appearance, and learned inter-object spatial relationships. The result is a set of tools designed to significantly enhance the productivity of analysts in exploiting emerging 3D data sources.
q Wilson functions of the second kind

The q-Wilson function of the second kind is defined as a Hilbert transform of the q-Wilson polynomials and is shown to be expressible as a very well-poised ${}_8 \phi _7 $ series. This is used to find the leading terms in the asymptotic expansions of the q-Wilson polynomials and functions of the second kind on the interval $ - 1 < x < 1$.
Efficient dynamic programming in presence of nuisance parameters

The dynamic programming approach for maximum a posteriori (MAP) estimation of Markov sequences is frequently proposed for problems in control theory, communications, and signal processing. It is usually assumed that the observation sequence is a perfectly known function of the Markov sequence of interest, except for some additive noise with known statistics. However, often the observation is not only a function of the Markov sequence but also of a vector of unknown nuisance parameters. It is shown how the dynamic programming methodology can be extended to estimate both the nuisance parameters and the Markov sequence, using a combined maximum-likelihood and MAP framework. The technique is efficient relative to other possible solutions. The problem of detecting and tracking moving targets observed by imaging sensors is used to demonstrate the efficiency of the procedure. >
Phase-amplitude study of clouds

Using artificially generated clouds we study the spectral phase and amplitude contribution to the cloud image. This is done by reconstructing the cloud image from spectral amplitude and/or phase only. Also, images are reconstructed from partial phase and amplitude in such a way that one may control the relative contribution of the phase and amplitude. We conclude that both phase and amplitude contribute to the cloud like appearance.
Measurement optimization in speckle interferometry: the influence of the imaging lens aperture

For many years, speckle interferometry has proven its usefulness for measuring deformation and contours of objects with rough surfaces. Nevertheless, the influence of a parameter as important as the lens aperture of the imaging system on the result of the measurement is still not precisely known. Generally, it is stated that the speckles have to be resolved by the camera and that therefore the lens aperture number should be large enough (e.g. f/11 or f/16 for typical applications with a standard CCD). This contribution shows, theoretically as well as experimentally, that it is not necessary to resolve the speckles when making measurements in speckle interferometry. The joint probability distribution of the pixel modulation and the pixel background intensity, which determines the percentage of valid pixels, is investigated for different lens aperture numbers, i.e. for different numbers of speckles per pixel. The comparison between theory and the experimental counterpart allows a number of speckles per pixel to be determined for any given aperture number and pixel size. It appears that the average pixel modulation remains high enough even with a relatively large number of speckles per pixel. The results lead to the conclusion that--especially when the total camera noise is low enough--lens apertures up to f/2 may be used. Thus, measurements are less constrained by limited laser power and decorrelation effects.
A Class of Decision Processes Showing Policy-Improvement/Newton–Raphson Equivalence

A condition expressed in Eq. (7) is given which, with one simplifying regularity condition, ensures that the policy-improvement algorithm is equivalent to application of the Newton–Raphson algorithm to an optimality condition. It is shown that this condition covers the two known cases of such equivalence, and another example is noted. The condition is believed to be necessary to within transformations of the problem, but this has not been proved.
On the structural controllability of compartmental systems

In this paper compartmental systems are modeled by a class of linearly parameterized matrix pairs and the controllability characteristics are expressed in terms of a compartmental graph. The result gives intuitive and physical information about the controllability and it extends the well-known result on the single-sink case to the multisink case. Furthermore, this result is applied to more special models, called undirected compartmental models, by which physical systems such as a class of liquid systems and of network systems, etc., can be concisely modeled.
The near field in the mixing of a round jet with a cross-stream

In the mixing of a jet with a cross-stream, it is found that in the near field, defined as the region of the flow from the jet exit to a distance of a few diameters downstream of this exit, a considerable amount of dynamical adjustment takes place. This near-field region characterizes the subsequent behaviour and development of the jet, its wake and the cross-stream in the vicinity of this mixing region. The rapid evolution of the flow gives rise to a pair of bound vortices attached to the lee side of the jet boundary, to fast development of the turbulent and mean vorticity, to a vortex-shedding system, and to the largest rates of entrainment of cross-stream flow into the jet. Furthermore, it is found that the geometrical configuration of the boundaries at the jet exit plays an important role in the mixing and development processes. An intrinsic method is proposed for the delineation of the flow boundaries between the jet and the cross-stream. Calculations of mass, momentum and vorticity fluxes have been made. The vorticity flux gives evidence of the rapid stretching and tilting of the vorticity vector field in the near-field region.
Empirical model of Poynting flux derived from FAST data and a cusp signature

Empirical models of the Poynting flux and particle kinetic energy flux, associated with auroral processes, have been constructed using data from the FAST satellite and are available online. The models output flux maps as a function of several geophysical parameters: (1) clock angle of the interplanetary magnetic field (IMF), (2) magnitude of the IMF in the GSM y‐z plane, (3) solar wind speed, (4) solar wind number density, (5) magnetic dipole tilt angle, and (6) the AL index (optional for Poynting flux). The choice of parameters is motivated by the Weimer potential model. Because the Poynting flux distribution has a heavy tail, care must be taken in applying the model to events that may be uncommon, and the model output includes a measure of quality based on the density of FAST orbits in the parameter space. The models are constructed by fitting the data to a sum of empirical orthogonal functions (EOFs), with coefficients modeled by quadratic equations in the geophysical parameters. The EOFs are constructed from the same data set using singular value decomposition, along with a smoothing/interpolation algorithm that minimizes curvature and incorporates uncertainty. Potential applications include specification of the auroral energy input for general circulation models. Basic findings from the model include verification of the importance of the auroral electrojets as features of auroral Poynting flux deposition and identification of the cusp as a third important feature. The cusp makes an important contribution to the overall energy budget when the IMF is north of ±90°.
COMPARISONS OF JOINT KINETICS IN THE LOWER EXTREMITY BETWEEN STAIR ASCENT AND DESCENT

ABSTRACT Stair locomotion has been used in the rehabilitation of the lower extremity as a motor performance test and multi-joint exercise. Controversies exist regarding joint loads during stair locomotion. The purposes of the study were to investigate the three-dimensional kinetics of the lower limb joints during stair locomotion, and to compare them with those during level walking. Ten normal young adults walked, and ascended and descended stairs in a gait laboratory while kinematic and kinetic data were collected and analyzed. The results showed that the intersegmental resultant forces at the joints during the activities were generally similar in pattern but the force magnitudes, moments and angular impulses were significantly different. The general impression that the loads in the lower limb were larger during stair descent than stair ascent only holds for certain kinetic variables. Most of the peak joint moments and angular impulses over the entire stance phase were bigger during stair ascent than descent. The study provides a complete knowledge of the three-dimensional loading patterns at and dynamic functions of the lower limb joints during level walking and stair locomotion. It will be helpful for the planning and evaluation of treatment programs for patients with neuromusculoskeletal pathologies in the lower extremities.
Time-Frequency Analysis of Three Strongly Variable Wolf-Rayet Stars: WR 6, WR 134, and WR 123

We apply the technique of time-frequency analysis to look for temporal changes in the variability power spectrum of the three strongly variable Wolf-Rayet stars, WR 6, WR 134, and WR 123, for which relatively long strings of homogeneous photometry are available. The observed changes of the power spectra may be related to the gradual restructuring of the stellar wind in the presence of "active" regions and/or nonradial pulsations or, in the case of the long-term variability of WR 134, caused by the presence of a low-mass companion.
Effects of beat-wave electron trapping on stimulated Raman and Thomson scattering

The influence of electron trapping on a large amplitude plasma oscillation driven by the nonlinear interaction of two electromagnetic waves (stimulated Raman scattering) is studied analytically and by means of numerical simulation. When the plasma oscillation is resonantly excited to sufficiently large amplitude and electron trapping occurs, there ensues considerable modification of the electron velocity distribution function. The stimulated scattering ceases to be a resonant three‐wave process but continues as induced scattering by resonant electrons (stimulated Thomson scattering). The scattering of the electromagnetic waves becomes slower, but does not terminate with the onset of particle trapping in the beat wave.
An alternative class of supersymmetries

The supersymmetry of Wess and Zumino is generalized to square roots of a class of ordinary Lie groups. The case of O2,3 is studied in detail. The authors obtain supersymmetric equations of motion for fields on a variant of de-Sitter space. The only dimensional parameter is the radius of space-time.
Detection of Change Point in Nonparametric Function with Unit-Root Noise by Wavelet

A wavelet method is proposed to detect jumps in a function which is observed with unit-root noise. We obtain critical values at any scale and prove the consistency of wavelet detection when the nonparametric function is smooth. It shows that the estimation of the number and locations of change points are consistent when there are change points in the nonparametric function. Simulation study supports our method.
Fabrication of SiC membrane HCG blue reflector using nanoimprint lithography

We designed and fabricated a suspended SiC-based membrane high contrast grating (HCG) reflectors. The rigorous coupled-wave analysis (RCWA) was employed to verify the structural parameters including grating periods, grating height, filling factors and air-gap height. From the optimized simulation results, the designed SiC-based membrane HCG has a wide reflection stopband (reflectivity (R) <90%) of 135 nm for the TE polarization, which centered at 480 nm. The suspended SiC-based membrane HCG reflectors were fabricated by nanoimprint lithography and two-step etching technique. The corresponding reflectivity was measured by using a micro-reflectivity spectrometer. The experimental results show a high reflectivity (R<90%), which is in good agreement with simulation results. This achievement should have an impact on numerous III-N based photonic devices operating in the blue wavelength or even ultraviolet region.
Mathematical under-preparedness: the influence of the pre-tertiary mathematics experience on students’ ability to make a successful transition to tertiary level mathematics courses in Ireland

Internationally, the consequences of the ‘Mathematics problem’ are a source of concern for the education sector and governments alike. Growing consensus exists that the inability of students to successfully make the transition to tertiary level mathematics education lies in the substantial mismatch between the nature of entrants’ pre-tertiary mathematical experiences and subsequent tertiary level mathematics-intensive courses. This paper reports on an Irish study that focuses on the pre-tertiary mathematics experience of entering students and examined its influence on students’ ability to make a successful transition to tertiary level mathematics. Brousseau's ‘didactical contract’ is used as an intellectual tool to uncover and describe the contract that exists in two case mathematics classrooms in Irish upper secondary schools (Senior Cycle). Although the authors are professional mathematics educators and well informed about classroom practice in Ireland, they were genuinely surprised by the very restrictive nature of this contract and the damaging consequences for students’ future mathematical education.
Annealing effect on the property of ultraviolet and green emissions of ZnO thin films

The mechanism of ultraviolet (UV) and green emission of ZnOthin filmsdeposited on (001) sapphire substrates by pulsed laser deposition was investigated by using postannealing treatment at various annealing temperatures after deposition.Structural, electrical, and optical properties of ZnOfilms have been also observed. As the postannealing temperature increased, the intensity of UV (380 nm) peak and the carrier concentration were decreased while the intensity of the visible (about 490–530 nm) peak and the resistivity were increased. The role of oxygen in ZnOthin film during the annealing process was important to the change of optical properties. The mechanism of the luminescence suggested that UVluminescence of ZnOthin film was related to the transition from near band edge to valence band, and green luminescence of ZnOthin film was caused by the transition from deep donor level to valence band due to oxygen vacancies. The activation energy derived by using the variation of green emission intensity was 1.19 eV.
In-situ imaging of reacting single-particle zeolites by non-linear optical microscopy

Zeolite catalysis has been exploited by the petrochemical industry since the 1940’s for catalytic cracking reactions of long chain hydrocarbons. The selectivity of zeolites strongly depends on a pore size, which is controlled by the chosen structure-directing agent (SDA) and by the SDA decomposition/removal process. Although zeolites are composed of micron-sized crystals, studies of zeolite materials typically focus on bulk (i.e., ensemble) measurements to elucidate structure-function information or to optimize catalysts and/or process parameters. To examine these phenomena on the microscale, non-linear optical microscopy is used to provide real-time imaging of chemical reactions in zeolites at temperatures exceeding 400°C. The template decomposition mechanism is studied, as elucidation of the mechanism is critical to understanding the relationship between the decomposition chemistry and the nanoscale features of the zeolite (topology, Si/Al ratio, added dopants). Forward stimulated Raman scattering (SRS), forward coherent anti-Stokes Raman scattering (CARS) and epi two-photon fluorescence (TPF) modalities are acquired simultaneously providing video-rate structural and chemical information. A high-temperature cell with gas inlet system is used for the study of reactions under various temperatures and gas environments. Examining the decomposition process with single-particle resolution enables access to ensemble-level and spatially-resolved behavior. Parallel experiments on bulk zeolite powders are conducted to enable comparison of ensemble and single-particle behavior during template decomposition. Our multi-technique approach has high potential for gaining insight into the link between nanoscale structure and catalytic activity and selectivity of zeolitic materials.
Star formation - The influence of velocity fields and turbulence

It is shown that the Jeans mass for gravitational collapse can be very much reduced by the influence of the velocity fields, even when allowance is made for non-isothermal gas behavior. We examine the role of turbulence in establishing the initial stellar mass function and show that the flattening and/or turnover at the low mass end may be a signature of interstellar turbulence. We consider also the implications of primordial turbulence for the formation of stars in the early universe.
High order filtering for nonlinear dynamical systems

We present a sequential and workable approach for high order filtering of nonlinear dynamical systems. First, an explicit form of the algorithm using the multidimensional Taylor series expansion of the Kushner-Stratonovitch equations is given, no restriction on the upper bound of the order is needed. Next, we generalize the formula for the expectation of the product of four to Gaussian random variables in order to establish the final form of the filtering algorithm.
Analysis of an eddy current and micromagnetic model

We consider a coupled eddy current and micromagnetic model describing the behaviour of dynamic electromagnetic phenomena in applications such as disk write heads. We first prove the existence of a weak solution to this nonlinear problem. Then we outline a numerical time-stepping scheme. Since the numerical method requires a nonstandard mixed boundary value eddy current problem to be solved at each time step, we show the existence and uniqueness of a solution for the corresponding eddy current problem. This is accomplished using an image principle and the verification of a suitable Babuška–Brezzi condition.
Image-based non-contact method to measure cross-sectional areas and shapes of tendons and ligaments

In determining the mechanical properties of biological tissues, accurate measurements of such geometrical attributes as cross-sectional area, volume and shape are needed. For soft tissues a non-contact technique is advantageous in determining these. A low cost, image-based, non-contact solution has been developed, suitable for determining the cross-sectional profiles of soft tissues with quasi-prismatic shapes such as tendons and ligaments. Digital processing of images of the object, illuminated by a sheet of laser light, is used to obtain cross-sectional ‘slices’ through it. The method was validated by using it to measure several rigid reference objects: two circular cylinders, a hex key and torx key, whose shape and dimensions had also been obtained by independent metrology. The smooth circular cross-sectional shape of the cylinder, the flat parallel faces of the hex key and the concave faces of the torx key were all reproduced by the laser-slice method. Their linear dimensions were correctly resolved to within 0.15 mm or less, and cross-sectional areas to within 0.17 mm2 or less. The method has been applied successfully to a selection of bovine digital extensor tendons. Some contained concavities on their surfaces, and their cross-sectional areas ranged from 14 mm2 to 49 mm2. The new method provides an accuracy and resolution better than or comparable to previous non-contact approaches, while avoiding some of their disadvantages.
NUMERICAL SIMULATIONS OF THERMAL CONVECTION IN A ROTATING SPHERICAL FLUID SHELL AT HIGH TAYLOR AND RAYLEIGH NUMBERS

In this study, we carry out numerical simulations of thermal convection in a rapidly rotating spherical fluid shell at high Taylor number Ta and Rayleigh number R with a nonlinear, three‐dimensional, time‐dependent, spectral‐transform code. The parameters used in the simulations are chosen to be in a range which allows us to study two different types of convection, i.e., single column and multi‐layered types, and the transition between them. Numerical solutions feature highly time‐dependent north–south open columnar convective cells. The cells occur irregularly in longitude, are quasi‐layered in cylindrical radius, and maintain alternating bands of mean zonal flow. The complex convective structure and the banded mean zonal flow are results of the high Taylor and Rayleigh numbers. The transition between the two types of convection appears to occur gradually with increasing Rayleigh and Taylor numbers. At a Taylor number of 107 the differential rotation pattern consists of an inner cylindrical region of sub.