Miracle-dz/UniFAR-FTUs huggingface dataset:
On the mechanical prototypes of fundamental hydrodynamic invariants and slow manifolds

Arnol'd's group-theoretical concept of generalized rigid body includes the Euler equations of motion of the classical gyroscope and ideal homogeneous fluid as particular representatives. Here, this concept is extended to motion in force fields with a scalar or vector potential and in a Coriolis force field. The concepts of generalized heavy top and generalized MHD system are introduced. As particular cases, they include, on the one hand, the Euler–Poisson equations of the classical heavy top and the Kirchhoff equations of motion of a solid body in a potential flow of an ideal incompressible fluid and, on the other hand, the Oberbeck–Boussinesq equations of motion of a heavy fluid and MHD equations. On this basis, mechanical prototypes are constructed for all known fundamental hydrodynamic invariants and global geophysical flows, including a prototype of the general atmospheric circulation.
Collaborative Indicators in Learning Games: An Immersive Factor

The work reported here takes place in the educational domain. We propose an approach of a learning environment based on a graphical representation of a course: a pedagogical dungeon equipped with the capacity for collaboration in certain activities. The emergence of online multiplayer games led us to apply the metaphor of exploring a virtual world, a dungeon, where each student embarks on a quest in order to collect knowledge related to a learning activity. In the dungeon, each room represents a place, sometimes a collaborative place, where students are supposed to acquire a particular concept. Although the students appreciate this approach, there is an obvious need for awareness, especially for the teacher. Indeed, the teacher needs to adapt his/her pedagogical session according to what is going on during the collaborative activity. We thus need to provide the teacher with collaborative indicators, and this information must be part of the game in order to keep the immersion of the teacher inside the game. In this paper, we focus especially on the need for collaborative indicators concerning both the knowledge (success and failure for sub activities) and the behaviour (talkative, cooperative) of the different students during the pedagogical session. In the first part, we describe deal with the support of the observation task for the teacher during a learning session. We then propose a classification of collaborative indicators as well as concrete examples from a real experiment achieved with students in our University. For immersion purposes, we represente these indicators by particular symbols such as coloured “auras” inserted inside the game itself.
Determination of beam intensity in a single step for IMRT inverse planning

In intensity modulated radiotherapy (IMRT), targets are treated by multiple beams at different orientations each with spatially-modulated beam intensities. This approach spreads the normal tissue dose to a greater volume and produces a higher dose conformation to the target. In general, inverse planning is used for IMRT treatment planning. The inverse planning requires iterative calculation of dose distribution in order to optimize the intensity profile for each beam and is very computation intensive. In this paper, we propose a single-step method utilizing a figure of merit (FoM) to estimate the beam intensities for IMRT treatment planning. The FoM of a ray is defined as the ratio between the delivered tumour dose and normal tissue dose and is a good index for the dose efficacy of the ray. To maximize the beam utility, it is natural to irradiate the tumour with intensity of each ray proportional to the value of the FoM. The nonuniform beam intensity profiles are then fixed and the weights of the beam are determined iteratively in order to yield a uniform tumour dose. In this study, beams are employed at equispaced angles around the patient. Each beam with its field size that just covers the tumour is divided into a fixed number of beamlets. The FoM is calculated for each beamlet and this value is assigned to be the beam intensity. Various weighting factors are incorporated in the FoM computation to accommodate different clinical considerations. Two clinical datasets are used to test the feasibility of the algorithm. The resultant dose–volume histograms of this method are presented and compared to that of conformal therapy. Preliminary results indicate that this method reduces the critical organ doses at a small expense of uniformity in tumour dose distribution. This method estimates the beam intensity in one single step and the computation time is extremely fast and can be finished in less than one minute using a regular PC.
Power spectra based Planck constraints on compensated isocurvature, and forecasts for LiteBIRD and CORE space missions

Compensated isocurvature perturbations (CIP), where the primordial baryon and cold dark matter density perturbations cancel, do not cause total matter isocurvature perturbation. Consequently, at the linear order in the baryon density contrast Δ, a mixture of CIP and the adiabatic mode leads to the same CMB spectra as the pure adiabatic mode. Only recently, Muñoz et al. showed that at the second order CIP leaves an imprint in the observable CMB by smoothing the power spectra in a similar manner as lensing. This causes a strong degeneracy between the CIP variance Δrms2 ≡ ⟨Δ2⟩ and the phenomenological lensing parameter AL. We study several combinations of the Planck 2015 data and show that the measured lensing potential power spectrum Cℓϕϕ breaks the degeneracy. Nested sampling of the ΛCDM+Δrms2(+AL) model using the Planck 2015 temperature, polarization, and lensing data gives Δrms2 = (6.9+3.0−3.1) × 10−3 at 68% CL. A non-zero value is favoured at 2. 3σ (or without the polarization data at 2.8σ). CIP with Δrms2 ≈ 7 × 10−3 improves the bestfit χ2 by 3.6 compared to the adiabatic ΛCDM model. In contrast, although the temperature data favour AL ≃ 1.22, allowing AL ≠ 1 does not improve the joint fit at all, since the lensing data disfavour AL ≠ 1. Indeed, CIP provides a rare example of a simple model, which is capable of reducing the Planck lensing anomaly significantly and fitting well simultaneously the high (and low) multipole temperature and lensing data, as well as the polarization data. Finally, we derive forecasts for two future satellite missions (LiteBIRD proposal to JAXA/NASA and Exploring Cosmic Origins with CORE proposal to ESA's M5 call) and compare these to simulated Planck data. Due to its coarse angular resolution, LiteBIRD is not able to improve the constraints on Δrms2 or AL, but CORE-M5 (almost) reaches the cosmic variance limit and improves the CIP constraint to Δrms2 < 0.6 (1.4) × 10−3 at 68 (95)% CL, which is nine times better than the current trispectrum based upper bound and six times better than obtained from the simulated Planck data. In addition, CORE-M5 will exquisitely distinguish between Δrms2 and AL. No matter whether CIP is allowed for or not, the uncertainty of the lensing parameter will be σ(AL) ≈ 0.012, in the case where the simulated data are based on the adiabatic ΛCDM model with AL = 1.
Elastoplastic Analysis of Circular Opening Based on a New Strain-Softening Constitutive Model and Its Engineering Application in Hydraulic Fracturing

Constitutive effect is extremely important for the research of the mechanical behavior of surrounding rock in hydraulic fracturing engineering. In this paper, based on the triaxial test results, a new elastic-peak plastic-softening-fracture constitutive model (EPSFM) is proposed by considering the plastic bearing behavior of the rock mass. Then, the closed-form solution of a circular opening is deduced with the nonassociated flow rule under the cavity expansion state. Meanwhile, the parameters of the load-bearing coefficient and brittles coefficient are introduced to describe the plastic bearing capacity and strain-softening degrees of rock masses. When the above two parameters take different values, the new solution of EPSFM can be transformed into a series of traditional solutions obtained based on the elastic-perfectly plastic model (EPM), elastic-brittle plastic model (EBM), elastic-strain-softening model (ESM), and elastic-peak plastic-brittle plastic model (EPBM). Therefore, it can be applied to a wider range of rock masses. In addition, the correctness of the solution is validated by comparing with the traditional solutions. The effect of constitutive relation and parameters on the mechanical response of rock mass is also discussed in detail. The research results show that the fracture zone radii of circular opening presents the characteristic of EBM > EPBM > ESM > EPSFM; otherwise, it is on the contrast for the critical hydraulic pressure at the softening-fracture zone interface; the postpeak failure radii show a linear decrease with the increase of load-bearing coefficients or a nonlinear increase with the increasing brittleness coefficient. This study indicates that the rock mass with a certain plastic bearing capacity is more difficult to be cracked by hydraulic fracturing; the higher the strain-softening degree of rock mass is, the easier it is to be cracked. From a practical point of view, it provides very important theoretical values for determining the fracture range of the borehole and providing a design value of the minimum pumping pressure in hydraulic fracturing engineering.
Optimal active and reactive power control of wind turbine driven DFIG using TLBO algorithm and artificial neural networks

This paper investigates the optimal active and reactive power control capabilities for typical wind turbine (WT) driven doubly fed induction generator (DFIG). The main objective is to determine the optimal rotor voltage to extract certain active and reactive power from the DFIG over wide ranges of wind speed. Teaching learning-based optimisation (TLBO) algorithm is a new heuristic optimisation technique, used to obtain the optimum rotor voltages to achieve reference active and reactive powers overall operating points. Artificial neural network (ANN) controller is used as an adaptive controller to predict the value of rotor voltage for all operating points. The ideal power curve of a 2 MW wind turbine has been estimated to design the active power controller. The stator reactive power control capability with the range of ±1.6 MVAR is developed. With the proposed control strategy, the DFIG-based wind farm provides maximum power point tracking (MPPT), fully active and reactive powers control. For all operated wind speeds, the adaptive proposed controller develops useful network support compared to the conventional DFIG-based wind farm. The proposed system is developed in MATLAB/Simulink environment.
Analysis of power factor in variable flux reluctance machines with MMF‐permeance model

This study investigates the underlying mechanism of low-power factor issue of variable flux reluctance machines (VFRMs) from the perspective of magneto-motive force (MMF)-permeance model. On the basis of a simplified analytical model, the relationship between the design parameters and the power factor is identified and systematically summarised into three predictable ratios: the rotor permeance ratio, stator/rotor-pole ratio and DC/AC winding ampere turns ratio. Specifically, the smaller the rotor-pole arc, the air-gap length, the rotor-pole number and the AC/DC winding ampere turns ratio are, the higher the power factor will be. In addition, the weak coupling between the field and armature windings caused by the modulation effect of the salient rotor is responsible for the low-power factor issue of VFRMs, regardless of the control scheme, winding configuration or saturation effect. A 6-stator-pole/4-rotor-pole VFRM is prototyped and tested for verification.
Hidden charged dark matter

Can dark matter be stabilized by charge conservation, just as the electron is in the standard model? We examine the possibility that dark matter is hidden, that is, neutral under all standard model gauge interactions, but charged under an exact {\rm U}(1) gauge symmetry of the hidden sector. Such candidates are predicted in WIMPless models, supersymmetric models in which hidden dark matter has the desired thermal relic density for a wide range of masses. Hidden charged dark matter has many novel properties not shared by neutral dark matter: (1) bound state formation and Sommerfeld-enhanced annihilation after chemical freeze out may reduce its relic density, (2) similar effects greatly enhance dark matter annihilation in protohalos at redshifts of z ∼ 30, (3) Compton scattering off hidden photons delays kinetic decoupling, suppressing small scale structure, and (4) Rutherford scattering makes such dark matter self-interacting and collisional, potentially impacting properties of the Bullet Cluster and the observed morphology of galactic halos. We analyze all of these effects in a WIMPless model in which the hidden sector is a simplified version of the minimal supersymmetric standard model and the dark matter is a hidden sector stau. We find that charged hidden dark matter is viable and consistent with the correct relic density for reasonable model parameters and dark matter masses in the range 1 GeV ≲ mX ≲ 10 TeV. At the same time, in the preferred range of parameters, this model predicts cores in the dark matter halos of small galaxies and other halo properties that may be within the reach of future observations. These models therefore provide a viable and well-motivated framework for collisional dark matter with Sommerfeld enhancement, with novel implications for astrophysics and dark matter searches.
Implementing Inkjet‐Printed Transparent Conductive Electrodes in Solution‐Processed Organic Electronics

Through the use of solution‐based materials, the field of printed organic electronics has not only made new devices accessible, but also allows the process of manufacture to move toward a high throughput industrial scale. However, while solution‐based active layer materials in these systems have been studied quite intensely, the printed electrodes and specifically the transparent conductive anode have only relatively recently been investigated. In this progress report, the use of metal nanoparticles within printed organic electronic devices is highlighted, specifically their use as replacement of the commonly used indium tin oxide transparent conductive electrode within organic photovoltaics (OPVs) and organic light emitting diodes (OLEDs). A cross fertilization between the applications is expected since an OPV device is essentially an inversely operated OLED. This report aims to highlight the use of inkjet‐printed nanoparticles as cost‐effective electrodes for printed optoelectronic applications and discusses methods to improve the conductive and interfacial properties. Finally, in an outlook, the use of these types of metal nanoparticle inks to manipulate light management properties, such as outcoupling, in the device is investigated.
Studies on plant regeneration and transformation efficiency of Agrobacterium mediated transformation using neomycin phosphotransferase II (nptII) and glucuronidase (GUS) as a reporter gene

Plant transformation mediated by Agrobacterium tumefaciens, a soil plant pathogenic bacterium, is the most used method for the introduction of foreign genes into plant cells and the subsequent regeneration of transgenic plants. We have standardized the tissue culture media for the regeneration and transformation with the vector LBA 4404 (pCAMBIA 2301), so that in future, this system may be exploited for the expression of antibody fragment (single chain variable fragment) in plants (plantibody). The transformed green shoots tested positive for neomycin phosphotransferase II (nptII) gene and glucuronidase (GUS) were screened, rooted on MS medium and subsequently hardened to harvest seeds. The transformation frequency of Agrobacterium (LBA 4404) with the binary vector pCAMBIA 2301 on the basis of GUS resistance was found to be 2.9%.
On the first-order collapse transition of a three-dimensional, flexible homopolymer chain model

We present simulation results for the phase behavior of flexible lattice polymer chains using the Wang-Landau sampling idea. These chains display a two-stage collapse through a coil-globule transition followed by a crystallization at lower temperatures. Performing a finite-size scaling analysis on the two transitions, we show that they coincide in the thermodynamic limit corresponding to a direct collapse of the random coil into the crystal without intermediate coil-globule transition.
Guest Editorial: Thermally conductive but electrically insulating materials for high voltage applications

In this High Voltage Special Issue the invited review and research articles cover the topic of thermally conductive but electrically insulating materials for high voltage applications. The review paper summarises the research progress on the development of epoxy resins with high pristine thermal conductivity, while the five research articles report different strategies for enhancing the thermal conductivity of polymer composites or polymer blends. The authors have a diverse range of experience across all fields of materials science, thus providing interdisciplinary perspectives to readers of the journal. The following topics relating to high voltage applications are by the papers in this Special Issue:
Validation and Standardization of the Weight Control Perceived Self-Effi cacy Inventory in a Mexican College Population

Purpose: The purpose of the study was to evaluate if the Weight Control Perceived Self-efficacy Inventory (WC-PSE) is reproducible in a Mexican college population. Methods and materials: This is an observational and prolective process study. Sixty subjects from two geographical regions of Mexico were invited to answer the WC-PSE on two separate occasions. Findings: The Content Validity Index was 0.96. The mean difference in the test retest was 0.7; Cronbach’s coefficient was α=. 95. The inventory was sensitive to detecting differences according to gender and degrees of body mass index. Conclusion: The WC-PSE inventory is reproducible and sensitive for application to a Mexican college population.
Comment on ‘Vector potential of the Coulomb gauge’

The expression for the Coulomb-gauge vector potential in terms of the ‘instantaneous’ magnetic field derived by Stewart (2003 Eur. J. Phys. 24 519) by employing Jefimenko’s equation for the magnetic field and Jackson’s formula for the Coulomb-gauge vector potential can be proven much more simply.
The effect of inhomogeneities on the distance to the last scattering surface and the accuracy of the CMB analysis

The standard analysis of the CMB data assumes that the distance to the last scattering surface can be calculated using the distance-redshift relation as in the Friedmann model. However, in the inhomogeneous universe, even if ⟨δρ⟩ = 0, the distance relation is not the same as in the unperturbed universe. This can be of serious consequences as a change of distance affects the mapping of CMB temperature fluctuations into the angular power spectrum Cl. In addition, if the change of distance is relatively uniform no new temperature fluctuations are generated. It is therefore a different effect than the lensing or ISW effects which introduce additional CMB anisotropies. This paper shows that the accuracy of the CMB analysis can be impaired by the accuracy of calculation of the distance within the cosmological models. Since this effect has not been fully explored before, to test how the inhomogeneities affect the distance-redshift relation, several methods are examined: the Dyer-Roeder relation, lensing approximation, and non-linear Swiss-Cheese model. In all cases, the distance to the last scattering surface is different than when homogeneity is assumed. The difference can be as low as 1% and as high as 80%. An usual change of the distance is around 20–30%. Since the distance to the last scattering surface is set by the position of the CMB peaks, in order to have a good fit, the distance needs to be adjusted. After correcting the distance, the cosmological parameters change. Therefore, a not properly estimated distance to the last scattering surface can be a major source of systematics. This paper shows that if inhomogeneities are taken into account when calculating the distance then models with positive spatial curvature and with ΩΛ ∼ 0.8−0.9 are preferred.
L-shell x-ray fluorescence measurements of lead in bone: accuracy and precision

This study aimed to quantify the accuracy and precision of a method for in vivo measurements of lead in bone using L-shell x-ray fluorescence (LXRF), the former via comparison with independent measurements of lead in bone obtained using electrothermal atomic absorption spectrometry (AAS) following acid digestion. Using LXRF, the lead content of adult human cadaver tibiae was measured, both as intact legs and as dissected tibiae with overlying tissue removed, the latter at several proximal–distal locations. After LXRF, each tibia was divided into nine cross-sectional segments, which were further separated into tibia core and surface samples for AAS measurement. The proximal–distal variability of AAS-measured core and surface tibia lead concentrations has been described elsewhere (the lead concentration was found to decrease towards both ends of the tibia). The subjects of this paper are the proximal–distal variability of the LXRF-measured lead concentrations, the measurement uncertainty and the statistical agreement between LXRF and AAS. There was no clear proximal–distal variability in the LXRF-measured concentrations; the degree of variability in actual tibia lead concentrations is far less than the LXRF measurement uncertainty. Measurement uncertainty was dominated by counting statistics and exceeded the estimate of lead concentration in most cases. The agreement between LXRF and AAS was reasonably good for bare bone measurements but poor for intact leg measurements. The variability of the LXRF measurements was large enough, for both bare bone and intact leg measurements, to yield grave concerns about the analytical use of the technique in vivo.
Incorporating parametric effects into functional principal components analysis

SUMMARY The ideas of functional principal component analysis are extended to deal with data that are hybrids of 'functional' and 'parametric' effects. The parametric effects may be more general than just the addition of a multiple of a given function. A detailed development is given in the case of shifts of the time axis for functions observed on a periodic interval, and some remarks are made for the extension to a far more general case. Given data, a Procrustes fitting method can be used to estimate the parametric effects. Several possible ways of treating the estimated parameter values are discussed. The methods are illustrated by reference to temperature data at 35 Canadian weather-stations.
Blow-up in Nonlinear Schroedinger Equations-I A General Review

The general properties of a class of nonlinear Schroedinger equations: iut + p:∇∇u + f(|u|2)u = 0 are reviewed. Conditions for existence, uniqueness, and stability of solitary wave solutions are presented, along with conditions for blow-up and global existence for the Cauchy problem.