Miracle-dz/UniFAR-FTUs huggingface dataset:
The interfacial stability of a ferromagnetic fluid

A normal magnetic field has a destabilizing influence on a flat interface between a magnetizable and a non-magnetic fluid. Stabilizing influences are provided by interfacial tension and gravity if the lighter fluid is uppermost. The critical level of magnetization for onset of the instability is derived for a fluid having a non-linear relation between magnetization and magnetic induction. Experiments using a magnetizable fluid, which contains a colloidal suspension of ferromagnetic particles, at interfaces with air and water are made and cover a wide range of density differences. Measurements confirm the prediction for critical magnetization, and it was found that, after onset, the interface took a new form in which the elevation had a regular hexagonal pattern. The pattern was highly stable, and the measured spacing of peaks agreed reasonably with that derived from the critical wave-number for the instability of a flat interface.
Solving Inverse Kinematics Constraint Problems for Highly Articulated Models

Given a goal position for the end effector of a highly articulated model, the task of finding the angles for each joint in the model to achieve the goal is an inverse kinematics problem. Redundancy of the degrees of freedom (DOF) can be used to meet secondary tasks such as obstacle avoidance. Joint limit constraints and collision detection can also be considered, as can loops. Solutions to redundant inverse kinematic problems are well developed. The most common technique is to differentiate the nonlinear equations and solve a linear Jacobian matrix system. The pseudoinverse of the Jacobian can be calculated via a singular value decomposition (SVD). The general SVD algorithm reduces a given matrix first to a bidiagonal form then diagonalizes it. The iterative Givens rotations method can also be used in our case, since the new Jacobian is a perturbation of previous one. Secondary tasks can be easily added to this matrix system, but it is nontrivial to generalize this problem to a highly redundant model in a complex environment in the computer graphics context. For this thesis, I implemented and compared several SVD techniques; and found that both general and iterative algorithms are of linear time-complexity when solving a three-row matrix. I also programmed and compared different methods to avoid one or multiple obstacles. A complete system was built to test the speed and robustness of the implementation.
On the propagation of brightening after filament/prominence eruptions, as seen by SoHO-EIT

Aims. To study the relationship between the propagation of brightening and erupting filaments/prominences in order to get some insight into the three-dimensional picture of magnetic reconnection. Methods. Analysis of the observations taken with the EIT (Extreme-ultraviolet Imaging Telescope) aboard SoHO (Solar and Heliospheric Observatory). Results. When the prominences/filaments erupted having one point fixed - asymmetric eruption - the brightening propagated along the neutral line together with the expansion/separation from the polarity inversion line'(PIL) as expected from the standard models. However in case of symmetric eruptions, the brightening propagated towards both end points starting at the middle. When the prominence/filament erupted faster then the speed of the propagating brightening was faster and vice-versa. Conclusions. Based on these observations we conclude that the eruption and magnetic reconnection - propagation (along the PIL) and separation (away from PIL) of the brightening - are dynamically coupled phenomena. These observations can be explained by a simple extension of the 2D models illustrating eruption and magnetic reconnection to a 3D model.
DIAGRAMMATIC REASONING SKILLS OF PRE-SERVICE MATHEMATICS TEACHERS

This study attempted to explore a possible relationship between diagrammatic reasoning and geometric knowledge of pre-service mathematics teachers. Diagrammatic reasoning skills, as a sequence of steps from visualization, to interpretation, to formalisms, are at the core of teachers' content knowledge for teaching. However, there is no course in the mathematics curriculum that systematically develops diagrammatic reasoning skills, except Geometry. In the course of this study, a group of volunteers in the last semester of their teacher preparation program were presented with "visual proofs" of certain theorems from high school mathematics curriculum and asked to prove/explain these theorems by reasoning from the diagrams. The results of the interviews were analyzed with respect to the participants' attained van Hiele levels. The study found that participants who attained higher van Hiele levels were more skilled at recognizing visual theorems and "proving" them. Moreover, the study found a correspondence between participants' diagrammatic reasoning skills and certain behaviors attributed to van Hiele levels. However, the van Hiele levels attained by the participants were consistently higher than their diagrammatic reasoning skills would indicate.
Simulations of turbulent thermal convection

A direct numerical simulation of thermal convection between horizontal plane boundaries has been performed, at a Rayleigh number Ra=9800 Rac, where Rac is the critical Rayleigh number for the onset of convection (Pr=0.72). The flow is found to be fully turbulent and analysis of the probability distributions for temperature fluctuations indicates that this is within the ‘‘hard turbulence’’ regime, as defined by the Chicago group. Good agreement is shown to exist between their experiments and the present simulation.
Anisotropic tetrahedral meshing via bubble packing and advancing front

This paper presents a new computational method for anisotropic tetrahedral meshing. The method can control element anisotropy based on a specified 3×3 tensor field defined over a volumetric domain. Our method creates a tetrahedral mesh in two steps: (1) placing nodes at the centres of tightly packed ellipsoidal cells, called bubbles, in the domain, and (2) connecting the nodes by a modified advancing front followed by local transformation. The method creates a high‐quality anisotropic mesh that conforms well to a specified tensor field. Copyright © 2003 John Wiley & Sons, Ltd.
Long-time symplectic integration: the example of four-vortex motion

Detailed comparisons are made between long-time numerical integration of the motion of four identical point vortices obtained using both a fourth-order symplectic integration method of the implicit Runge-Kutta type and a standard fourth-order explicit Runge-Kutta scheme. We utilize the reduced hamiltonian formulation of the four-vortex problem due to Aref & Pomphrey. Initial conditions which give both fully chaotic and also quasi-periodic motions are considered over integration times of order 106-107 times the characteristic time scale of the evolution. The convergence, as the integration time step is decreased, of the Poincaré section is investigated. When smoothness of the section compared to the converged image, and the fractional change in the hamiltonian H are used as diagnostic indicators, it is found that the symplectic scheme gives substantially superior performance over the explicit scheme, and exhibits only an apparent qualitative degrading in results up to integration time steps of order the minimum timescale of the evolution. It is concluded that this performance derives from the symplectic rather than the implicit character of the method.
Induced pulse voltage in twisted Vicalloy wire with compound magnetic effect

When a Vicalloy wire (40wt%Fe-50Co-10V) is twisted, the coercivity reduces due to large stress. The pulse-inducing characteristics and domain wall propagation are investigated utilizing this effect on such compound magnetic wire. We find that the generating point of inverse nucleation varies according to the strength of set field Hs and the demagnetizing field near the end of the wire, when the entire compound magnetic wire is excited by an asymmetrical field. Moreover, we find that the velocity of domain wall propagation in the smaller coercivity layer to be 400-500 (m/s) at Hs=16-25 Oe.
Quantitative elasticity imaging

Quantitative elasticity imaging is investigated for a wide range of gel-based, tissue equivalent phantoms and excised tissue specimens. To do this, strain imaging methods have been developed for very large surface deformations. Images produced by this approach exhibit a high signal to noise ratio (SNR). Results are presented demonstrating both the accuracy and sensitivity of the method for imaging internal strain in models of kidney pathology. In particular, strain images have been used to detect renal scar in a rabbit model of chronic nephritis before any detectable change in kidney function. Finally, reconstruction of the elastic modulus based on these high SNR strain images has been tested. Results on gel-based phantoms indicate that a method based on stress continuity can be used to clearly identify bounded inclusions in an otherwise infinite, homogeneous medium
A New Approach for Synthesizing Both the Radiation and Scattering Patterns of Linear Dipole Antenna Array

A new approach for simultaneously synthesizing the radiation and scattering patterns of linear dipole antenna array is investigated. In this method, the analytical formulas of the radiation field and scattered field of linear dipole antenna array are derived in terms of self-impedance, mutual-impedance and terminal load impedance. So the mutual coupling effects between the elements can be taken into account. Based on these two formulas, the desired radiation and scattering patterns of the array can be synthesized simultaneously by optimizing element placement. As an example, the proposed method is used in designing a linear dipole antenna array with low radiation and scattered sidelobe level. Numerical results validating the accuracy and great effectiveness of the method are also provided in this paper.
Novel method for solving radial distribution networks

The paper presents a novel method using load flow for solving radial distribution networks. The radial feature of the network has been fully exploited to develop an algorithm by a unique lateral, node and branch numbering scheme. The proposed method involves only the evaluation of simple algebraic voltage expressions without any trigonometric functions. Thus, computationally, the proposed method is very efficient and requires less computer memory storage as all data is stored in vector form. The proposed method can easily handle different types of load characteristics. Several Indian rural distribution networks have been successfully solved using the proposed method known as the forward sweeping method.
Ignition and Combustion of Boron Particles at One to Ten Standard Atmosphere

The ignition and combustion of boron particles are investigated at high pressures in the range of 1–10 atm. Observation results show that the combustion of 2 μm amorphous boron particles occurs in two continuous stages. The combustion times of boron particles are measured. The first stage combustion time decreases slightly with an increase of pressure, whereas the second stage combustion time shows strong dependence on pressure. Measured first stage combustion times are compared with the predictions of two typical numerical models, the King model and the Yeh and Kuo model. Both models overpredict the experimental data at higher pressures. The governing equations of the two models have been analyzed to reveal the reasons for the inaccuracy of the predictions. A new model has been developed on the basis of the Yeh and Kuo model, by introducing B(s)+3/4O2(g)→1/2B2O3(l) as the global reaction of B and O2. The prediction of the new model is in good agreement with experimental results, especially under high-pr.
Numerical study of two‐dimensional stochastic NLS equations

In this article, we numerically solve the two‐dimensional stochastic nonlinear Schrödinger equation in the case of multiplicative and additive white noises. The aim is to investigate their influence on well‐known deterministic solutions: stationary states and blowing‐up solutions. In the first case, we find that a multiplicative noise has a damping effect very similar to diffusion. However, for small amplitudes of the noise, the structure of solitary state is still localized. In the second case, a local refinement algorithm is used to overcome the difficulty arising for the computation of singular solutions. Our experiments show that multiplicative white noise stops the deterministic blow‐up that occurs in the critical case. This extends the results of Debussche and Di Menza (Physica D, 162(3–4) 2002, 131–154) in the one‐dimensional case. © 2005 Wiley Periodicals, Inc. Numer Methods Partial Differential, 2005.
Perturbations of Optical Solitons and Quasi-Solitons

The method of multiple-scale perturbation method is developed in a new way to study the propagation of pulses through an optical fiber described by the perturbed Nonlinear Schrödinger's equation. We show that, by newly introducing a proper definition of the phase of the soliton for the first time, one can obtain the corrections to the pulse where the usual soliton perturbation approach fails. A comparison is made with results obtained by other methods in various other works as well as with numerical simulations.
Noniterative blind image restoration based on estimation of a significant class of point spread functions

Blind image restoration means estimating the true image from an observed degraded image, with incomplete or little prior knowledge of the blur function and the true image. Commonly, iterative or recursive methods are applied to this problem, but they are usually time-consuming, uncertain, and divergent. Focusing on a limited but significant class of point spread functions (heavy-tailed Levy processes), a noniterative blind image restoration method is proposed, which directly estimates the point spread functions from the degraded image's Fourier amplitude and restores the image by general slow evolution of a continuation boundary. This method is based on the fast Fourier transform, so it can accomplish the blind restoration of a 512 X 512 image in seconds of CPU time on a current desktop platform. From several experiments on synthetic blurred images and on actual images, it is found that the quality of the restored images has been greatly improved, and many fine details are restored, by applying this method. (c) 2007 Society of Photo-Optical Instrumentation Engineers.
A Critical Discourse Analysis of News Discourse on in The Times

The Brexit event has attracted wide attention from the world since its occurrence and has a significant impact on the world development pattern and the global economy. For ordinary people, news is not first-hand information, but the product of processing by news agencies and journalists, so news discourse is an effective way to spread ideology-news discourse is an effective way to spread their ideologies who wrote this discourse by using various language strategies. This study examines and reveals how news reporting is ideological. It looks at how The Times uses language to spread ideologies. Based on the analytical model of Fairclough from the perspective of critical discourse analysis, this study analyzed 50 news reports concerning the issue of Brexit from The Times ( from 23 June 2016 to 31 Dec. 2020). Both quantitative analysis and qualitative analysis are employed to explore the linguistic features. The findings highlight how the Times represents Brexit in its reporting and how the representations favor the interests of the party or particular groups. The findings of the study are as follows: Firstly, language is not used randomly when it comes to news reporting. Secondly, the different camps portrayed different images of the EU and the UK government. The findings show how news language is laden with ideological meanings and orientations and only a critical investigation can reveal that the news media use various discursive strategies when reporting important issues and that these strategies are ideological biased.
Characterization of the Shallow and Deep Levels in Si Doped GaN Grown by Metal-Organic Vapor Phase Epitaxy

Si doped GaN with room temperature free carrier concentration 1.1× 1017 cm-3 studied using the Hall effect exhibits exponential carrier freeze-out over a large range with activation energy 28.0± 0.5 meV; however, resistivity dependence on temperature suggests carrier hopping occurs at low temperature. GaN with greater Si concentration displays metallic impurity band conduction following the two-band model. Deep level transient spectroscopy results show a negligible concentration of other deep donors from native defects or unintentionally included impurities indicating that the active shallow donor is uniquely Si; however, photoluminescence tests show broad yellow emission with peak energy ∼ 2.2 eV commonly observed in Si doped GaN.
Using interpretative phenomenological analysis to probe the lived experiences of persistent postural-perceptual dizziness (PPPD)

BACKGROUND: Persistent Postural-Perceptual Dizziness (PPPD) is a chronic neuro-vestibular condition characterised by subjective dizziness, non-spinning vertigo, and postural imbalance. Symptoms are typically induced by situations of visuo-vestibular conflict and intense visual-motion. OBJECTIVE: Little research has focused on the lived experiences of people with PPPD. Therefore, our objective was to present an in-depth exploration of patient experiences and sense-making, and the effect of PPPD on psycho-social functioning. METHODS: We conducted semi-structured interviews with 6 people with PPPD, who were recruited from an Audiovestibular department in Wales. We present a case-by-case Interpretive Phenomenological Analysis (IPA) for each participant and present common themes. RESULTS: Our analysis revealed a range of superordinate and subordinate themes, individualised to each participant, but broadly described under the following headings: dismissal and non-belief, identity loss, dissociative experiences, poor psychological well-being and processes of sense-making. CONCLUSION: The qualitative experiences documented in this study will help clinicians and researchers to better understand the lived experiences of PPPD, how PPPD patients make sense of their symptoms, and the psycho-social impacts of the condition.
On continuity of geodesic frameworks of flows on surfaces

For flows on an orientable closed surface of larger genus (that is, of genus ) a special geodesic distribution (the geodesic framework of the flow) is constructed that consists of geodesics with the same asymptotic directions as the trajectories of the flow and that is a complete topological invariant of the irrational flows on such surfaces. The problem of the dependence of the geodesic framework on a perturbation of the flow (or on the parameter of a family of flows) is considered. It is shown that an irreducible elementary irrational geodesic framework of a flow depends continuously on the perturbation of the flow (which is analogous to the continuous dependence of an irrational Poincare rotation number on a perturbation of a flow).
Privacy-Preserving Biometric Authentication: Cryptanalysis and Countermeasures

In this article, we cryptanalyzed a Verifiable Threshold Predicate Encryption (VTPE) enabled Privacy-Preserving Biometric Authentication (PPBA) protocol reported in IEEE-TDSC and revealed discrepancies between its security claims and our security analysis. To be precise, the underlying authentication and key agreement scheme which is based on a challenge-response mechanism and watermark signal unsatisfactorily meets the following security scenario: (a) resistance to man-in-the-middle attacks, (b) biometric template protection, and (c) user anonymity and untraceability. To address these issues, we utilize Physical Unclonable Functions (PUF) to design a PUF driven Verifiable Threshold Predicate Encryption (PUF-VTPE) scheme and a secure PPBA protocol. The PUF-VTPE-based PPBA protocol equips with dual authentication using biometric and mobile device, which offers strong authenticity before establishing the session key. Simultaneously, the non-invertible property of PUF protects the biometric templates in the physical layer. The proposed storage-free mechanism that hides the challenge of device PUF in biometric template alleviates data leakage caused by storage challenges in PUF-based authentication protocols. Moreover, the experimental analysis suggests that the proposed PPBA protocol possesses ISO/IEC 24745 criteria of non-invertibility, unlinkability, and revocability. Additionally, the proposed PPBA protocol reduces the computational cost by about 50% compared to that of the cryptanalyzed scheme.
Auditory masking: Need for improved conceptual structurea)

Even in simpler times, some people (e.g., Tanner) found it useful to ask “What is masking? ” Independent of the extent to which this question was adequately answered even in those times, it is clear that the current expanded interest in central auditory processing has raised this question anew. In this note, comments are made about masking-related issues that illustrate the kinds of questions that need to be considered in attempting to develop a conceptual structure that can be effectively used to define, classify, study, and model auditory masking.
Non-periodic boundary model with soft transition in molecular dynamics simulation

The imposition of non-periodic boundary conditions is a challenging issue in molecular dynamics (MD) simulation because of the difficulty in reconstructing the detailed particle dynamics from the few state variables. In this paper, a general scheme for the imposition of this kind of boundary conditions is presented. The complete model includes the imposition of Dirichlet boundary conditions and applying the boundary force to ensure the continuity of flow properties. Both the flux and the boundary force are introduced in a consistent way with the microscopic dynamics of the molecular system. Moreover, a soft constraint mechanism is included to correct the instantaneous deviation of the local state. A uniform flow and a Poiseuille flow of Lennard-Jones fluid is simulated using the boundary model. The results demonstrate that the fluctuation of flow properties near the boundary is kept at a low level, and the model is stable even subject to internal disturbance.