Miracle-dz/UniFAR-FTUs huggingface dataset:
Experimental comparison between nonholonomic and vakonomic mechanics in nonlinear constrained systems

It is known that there exist two types of methods to derive the equations of motion for mechanical systems subject to constraints. They are called nonholonomic and vakonomic mechanics. Lewis and Murray showed some simulations for two models of a ball on a rotating table, which are modeled by nonholonomic and vakonomic mechanics, and carried out experiments using a laboratory equipment. They concluded that nonholonomic mechanics provides a good model for a ball on a rotating table. However, they did not show the details of experiments, and hence there exist some ambiguous parts in their paper. Hence, we perform additional experiments for a ball on a rotating table using a laboratory equipment of a ball on a rotating table, and compare simulation and experimental results. In this manner, we can confirm that nonholonomic mechanics shows better performances in comparison with vakonomic mechanics as Lewis and Murray asserted.
FINITE ELEMENT ANALYSIS OF CERVICAL SPINE WITH DIFFERENT CONSTRAINED TYPES OF TOTAL DISC REPLACEMENT

Various designs of cervical total disc replacement (CTDR) have been introduced and employed in an attempt to avoid disadvantages of the fusion surgery. The purposes of this study were to evaluate the effects of the range of motion (ROM), the instantaneous center of rotation (ICR) and the facet joint force (FJF) with different constrained types of CTDR devices. A three-dimensional finite element (FE) model of intact cervical spine (C3-7) was made from CT scans of a normal person and validated. Postoperative FE models simulating CTDR implantation at the C5-6 disc space were made for CTDR-I (constrained design) and CTDR-II (nonconstrained design), respectively. Hybrid protocol (intact: 1 Nm) with a compressive follower load of 73.6 N was applied at the superior endplate of the C3 vertebral body. The inferior endplate of C7 vertebral body was constrained in all directions. At the index level, CTDR-I showed a higher increase in segmental motion and FJF than CTDR-II in extension, lateral bending and axial rotation. The CTDR-II with an elastomer-type core reproduced a near physiological ICR of the intact model in extension and axial rotation. Abnormal kinetic and kinematic changes related to the CTDR may induce surgical level problems and cause long-term failure of spinal surgery.
Relativistic electron precipitation during magnetic storm main phase

Relativistic electrons can have cyclotron resonances with electromagnetic ion-cyclotron waves. The resonant energy is generally well above 1 Mev throughout the magnetosphere, but it can fall to near 1 Mev just within the plasmapause. This also corresponds to the region where ring current (10–50 kev) protons are expected to be strongly unstable. The resulting ion-cyclotron wave amplitude necessary to precipitate ring current protons leads to electron lifetimes near the strong diffusion limit. Thus, >1-Mev electrons whose drift orbits intersect the stormtime plasmapause should rapidly be precipitated in the region 3
Repeated Measurements Designs, II

Abstract : Repeated measurements designs are concerned with scientific experiments in which subjects (experimental units) are repeatedly exposed to a sequence of different or identical tests (treatments). These designs have application in many branches of scientific inquiry such as: Biology, education, food science, marketing, environmental engineering, medicine and pharmacology. The objectives in the paper are threefold: (1) To construct some families of repeated measurements designs which researchers have been seeking. These designs are useful for those cases where a subject cannot participate in all tests as in many pharmacological studies; (2) to provide an extensive list of references on repeated measurements designs which it is hoped, will be useful to those who want to do further research in this area; (3) to state some unsolved problems which have an immediate application. (Author)
ANALYSIS OF ORGANIZATIONAL CULTURE IN THE PUBLIC SECTOR

A large variety of organizational culture are evident in the public sector during the strategy implementation process. The Competing Values Model was used to investigate organizational culture and its influence on strategy implementation to understand this better. This study found that a culture that facilitates strategy implementation in the public sector includes character traits such as being flexible, discrete, external focus, and differentiate In contrast, the hierarchal culture that includes characters requiring top-down control and formal rules for decision-making hinders strategy implementation.
Arbitrarily modulated beam for phase-only optical encryption

Optical encryption has attracted more and more attention recently due to its remarkable advantages, such as parallel processing and multiple-dimensional characteristics. In this paper, we propose to apply an arbitrarily modulated beam for phase-only optical encryption. In optical security systems, the plane wave is commonly used for the illumination, and unauthorized receivers may easily obtain or estimate the information related to the illumination beam. The proposed strategy with an arbitrarily modulated illumination beam can effectively enhance system security, since a beam modulation pattern (such as a pinhole-array pattern or a random phase-only pattern) can be considered an additional security key. The phase-only optical encryption is taken as an example for illustrating the validity of the proposed method; however it could be straightforward to apply the proposed strategy to other optical security systems.
A Collocation Method for Numerical Solutions of Coupled Burgers’ Equations

In this paper, we propose a collocation–based numerical scheme to obtain approximate solutions of coupled Burgers’ equations. The scheme employs collocation of modified cubic B-spline functions. We have used modified cubic B-spline functions for unknown dependent variables u, v, and their derivatives w.r. t. space variable x. Collocation forms of the partial differential equations result in systems of first–order ordinary differential equations (ODEs). In this scheme, we did not use any transformation or linearization method to handle nonlinearity. The obtained system of ODEs has been solved by strong stability preserving the Runge-Kutta method. The proposed scheme needs less storage space and execution time. The test problems considered in the literature have been discussed to demonstrate the strength and utility of the proposed scheme. The computed numerical solutions are in good agreement with the exact solutions and competent with those available in earlier studies. The scheme is simple as well as easy to implement. The scheme provides approximate solutions not only at the grid points, but also at any point in the solution range.
Anisotropic Particle Distribution in Dilute Suspensions of Solid Spheres in Cylindrical Couette Flow

The pair distribution function of the particles in a noncolloidal suspension was for the first time measured experimentally. Evidence of anisotropy in dilute suspensions of solid spheres is presented. Suspensions of polystyrene spheres in silicone oils with volume fractions 0.01⩽c⩽0.05 were subjected to cylindrical Couette flow in a Weissenberg Rheogoniometer. The experimental conditions were such that the Reynolds number based on the particle radius was very small, O(10−7) and the particle Peclet number very large, O(105), so that inertial effects and Brownian motion were negligible relative to viscous effects. Suspended spheres on a plane perpendicular to the axis of rotation were observed using a video camera interfaced with a VICOM image processing computer. Using automatic data gathering and processing techniques specially developed for this purpose, an analysis of the relative positions of the spheres showed that (under shear) the spheres were not uniformly distributed in the suspension, but rather .
Observational constraints on viscosity in AGN accretion discs

La variabilite UV observee dans les spectres des noyaux actifs de galaxies peut etre causee par des instabilites du disque d'accretion et peut etre utilisee pour calculer la viscosite. La comparaison des echelles de temps thermiques avec les echelles de temps observees de la variabilite dans 10 galaxies Seyfert et 16 quasars indique des valeurs pour le parametre de viscosite α de l'ordre de 0.01 dans la plupart des cas
Towards a new hybrid cumulus parametrization scheme for use in non‐hydrostatic weather prediction models

Classical mass flux parametrization schemes for cumulus convection generally transport heat and moisture only but do not include a net mass transport. This is well justified for large grid spacings comprising the whole convective circulation in the local grid column, such that all convective mass fluxes locally cancel out. A conceptual problem arises for finer grid spacings as used in contemporary numerical weather prediction (NWP) models, when convection becomes partially resolvable. This problem can be overcome by the hybrid approach presented here. Only updraft and downdraft are parametrized with a net mass transport; the environmental subsidence is treated by the grid‐scale equations. The total mass flux in the continuity equation is split into a grid‐scale and a subgrid‐scale contribution. This parametrization scheme is designed for use in any nonlinear, non‐hydrostatic and fully compressible NWP model. We here have chosen the Lokal–Modell (LM) of Deutscher Wetterdienst.
Wave power studies of cusp crossings with the Polar satellite

Burst data from the electric field instrument (EFI) on the Polar satellite are used to classify cusp wave properties and the association of the observed waves with particle populations. The most intense wave type (most commonly triggering burst mode data collection) are the broadbanded waves which are then studied in detail using the three-dimensional resolution of the EFI. Finite wavelength effects are removed using two techniques: time-shifting of the sphere potentials to a spacecraft body reference time and spin angle selection. The corrected electric field signal exhibits a uniform spectrum in two dimensions. The wave properties are consistent with two-dimensional turbulence, with phase velocities smaller than the spacecraft velocity and frequency as low as (or lower than) the oxygen gyrofrequency. Owing to their low frequency, we conclude that these waves cannot resonate with and thus heat the ions. The broad k-spectrum and very low frequency in the plasma frame points toward drift or shear instabilities for wave excitation.
Patient Flow in Congested Intensive Care Unit /Step-down Unit system: Premature Step-down or not?

A Step-Down Unit (SDU) provides an intermediate Level of Care for patients from an Intensive Care Unit (ICU) as their condition becomes less acute. SDU congestion, as well as upstream patient arrivals, forces ICU administrators to incur costs, either in the form of overstays or premature step-downs. Based on a proxy for patient acuity level called the `Nine Equivalents of Nursing Manpower Score (NEMS), patients were classified into two groups: high-acuity and low-acuity. Two patient flow policies were developed that select actions to optimize the system s net health service benefit: one allowing for premature step-down actions, and the other allowing for patient rejection actions when the system is congested. The results show that the policy with patient rejection has a net health service benefit that significantly exceeds that of the policy with the premature step-down option. Based on these results, it can be concluded that premature step-down contributes to congestion downstream. Counter-intuitively, premature step-down should therefore be discouraged and patient rejection actions should be further explored as viable options for congested ICUs.
Invexity of supremum and infimum functions

Under suitable assumptions we establish the formulas for calculating generalised gradients and generalised directional derivatives in the Clarke sense of the supremum and the infimum of an infinite family of Lipschitz functions. From these results we derive the results ensuring such a supremum or infimum are an invex function when all functions of the invex. Applying these results to a class of mathematical programs, we obtain necessary and sufficient conditions for optimality.
Tracking the COVID-19 vaccine equity, distribution, and cases in the global south

The rapid development of vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has proved to make an important contribution in reducing both viral transmission and disease burden. In this study, we tracked the COVID-19 vaccine equity, distribution, and cases in global south countries using country-level data from Our World in Data using an event study analysis. We used data from 149 global south and 59 non-global south countries from January 2020 to May 2022. All non-global south and 90.32% of global south countries had universal availability of vaccines. The median time since the introduction of the first COVID-19 vaccine in the global south was almost eight weeks later than in non-global south countries. The median number of people fully vaccinated per hundred (68.8 vs 50.31), and the total number of boosters administered per hundred (45.7 vs. 13.02) were higher in non-global south countries compared to global south countries. Using the event study analysis, we found a significant reduction of COVID-19 new cases and deaths after the first COVID-19 vaccination rollout compared to the baseline in global south countries, average coefficient p-value <0.001. Programs aiming at improving vaccine access and distribution to global south countries are essential to effectively control COVID-19.
Solar Polar Magnetic Fields: Comparing Full-disk and High-resolution Spectromagnetograph Data

This is the first systematic comparison between photospheric polar magnetic field data from a full-disk synoptic observing program, the National Solar Observatory’s Synoptic Optical Long-term Investigations of the Sun Vector Spectromagnetograph (SOLIS/VSM), and a high-resolution vector spectromagnetograph, the Hinode Solar Optical Telescope Spectropolarimeter (SOT/SP). Polar magnetic fluxes derived from longitudinal magnetic field measurements from both telescopes and from SOT/SP full-Stokes vector data are all compared in the form of polar synoptic maps. Measurements taken over 35 day periods with advantageous rotation axis tilt angle are used; observations extend to the poles, and no synthetic pole-filling is needed. Polar fluxes are derived from longitudinal data assuming an approximately radial field, whereas those derived from vector data are based on measured vector magnitude and direction. However, the full-vector measurements may have a detection problem: polar fields are observed as mostly transverse from (near) Earth, and Zeeman sensitivity to transverse fields is significantly lower than for longitudinal fields. Accordingly, the SOT/SP vector-based polar fluxes are lower than the longitudinal-based fluxes from both telescopes, a result driven by pixels without sufficient Q and U signals for the full-Stokes inversions to detect significant radial field but with good Stokes V signal implying a significant field. Furthermore, the SOT/SP longitudinal-based fluxes are significantly higher than their VSM counterparts because of superior seeing-free spatial resolution and longer observation time. The SOT/SP longitudinal-based polar fluxes appear large enough to account for radial interplanetary field measurements whereas the SOT/SP vector-based and the VSM ones are generally too low.
The Possible Tidal Demise of Kepler’s First Planetary System

We present evidence of tidally-driven inspiral in the Kepler-1658 (KOI-4) system, which consists of a giant planet (1.1R J, 5.9M J) orbiting an evolved host star (2.9R ⊙, 1.5M ⊙). Using transit timing measurements from Kepler, Palomar/WIRC, and TESS, we show that the orbital period of Kepler-1658b appears to be decreasing at a rate Ṗ=131−22+20 ms yr−1, corresponding to an infall timescale P/Ṗ≈2.5Myr . We consider other explanations for the data including line-of-sight acceleration and orbital precession, but find them to be implausible. The observed period derivative implies a tidal quality factor Q⋆′=2.50−0.62+0.85×104 , in good agreement with theoretical predictions for inertial wave dissipation in subgiant stars. Additionally, while it probably cannot explain the entire inspiral rate, a small amount of planetary dissipation could naturally explain the deep optical eclipse observed for the planet via enhanced thermal emission. As the first evolved system with detected inspiral, Kepler-1658 is a new benchmark for understanding tidal physics at the end of the planetary life cycle.
On the operation of composition of distributions

The proofs of the results of P. Antosik [3] on the distributional composition of distributions (in the sense of Mikusinski's theory of irregular operations), which contained essential gaps, are completed due to some measure theory techniques, and the results are generalized. The obtained theorems can be applied to prove some formulas, which may be interesting to physicists, concerning the substitution of measures (in particular, the Dirac delta distribution) to continuous functions.
Reaction of N+ Ion with H2, HD, and D2 at Low Temperatures: Experimental Study of the Pathway to Deuterated Nitrogen-containing Molecules in the Interstellar Medium

This work is motivated by many observations of nitrogen hydrides including their isotopologues in the interstellar space. We studied the formation of NH+ and ND+ ions in the nearly thermoneutral hydrogen abstraction reactions of N+ ions with H2, HD, and D2 at temperatures from 300 K down to 15 K using a variable-temperature 22-pole radio frequency ion trap. For the reaction of N+ with HD, the branching ratios for production of ND+ and NH+ ions were also determined. The activation energies of all four reaction channels were determined from the temperature dependencies of the measured reaction rate coefficients. Under the assumption of no energy barriers on the reaction paths, we derive the vibrationless energy change (i.e., the difference of equilibrium Born–Oppenheimer potential energies of products and reactants) in the reactions as ΔE e = (103 ± 3) meV.
Recent Progress in Quantum Key Distribution Network Deployments and Standards

Quantum key distribution (QKD) provides in principle unconditional security of key sharing based on the laws of physics only. In the last decade, several experimental and commercial QKD networks have been built and operated worldwide. Demonstrational applications of QKD in financial institutions, government networks, and critical infrastructures such as the power grid have been initially explored. However, large-scale deployment and full-scale commercialization of QKD networks still faces some technological and standardisation challenges. In this paper, recent developments and in-field deployments of QKD networks are reviewed and advancements in QKD standardisation are also discussed.
Electrical characterization of (Ni/Au)/Al0.25Ga0.75N/GaN/SiC Schottky barrier diode

In this work we report on the characteristics of a (Ni/Au)/AlGaN/GaN/SiC Schottky barrier diode (SBD). A variety of electrical techniques, such as gate current-voltage (I-V), capacitance-voltage (C-V), and deep level transient spectroscopy (DLTS) measurements have been used to characterize the diode. The behavior study of the series resistance, RS, the ideality factor, n, the effective barrier height, Φb, and the leakage current with the temperature have emphasized an inhomogeneity of the barrier height and a tunneling mechanism assisted by traps in the SBD. Hence, C-V measurements successively sweeping up and down the voltage have demonstrate a hysteresis phenomenon which is more pronounced in the temperature range of 240 to 320 K, with a maximum at ∼300 K. This parasitic effect can be attributed to the presence of traps activated at the same range of temperature in the SBD. Using the DLTS technique, we have detected one hole trap having an activation energy and a capture cross-section of 0.75 eV and 1.0.
Conjugate observations of ENA signals in the high‐altitude cusp and proton auroral spot in the low‐altitude cusp with IMAGE spacecraft

On 28 April 2001, significant enhancements of neutral atom signals were detected in the direction of a high‐altitude cusp by the Low‐Energy Neutral Atom (LENA) imager onboard the Imager for Magnetopause‐to‐Aurora Global Exploration (IMAGE). Simultaneously, proton auroral emission was observed in the low‐altitude cusp by the Far‐Ultraviolet Instrument (FUV) on the IMAGE spacecraft. The temporal variations of their intensities showed a good correlation, suggesting they had a common source. During a brief period, the proton auroral spot moved antisunward and dawnward in conjunction with the motion of the ionospheric footprint of the LENA cusp signal. The Tsyganenko‐96 model shows that the possible source location of the LENA cusp signals maps to the FUV spot. Considering the solar wind variations, we have attributed this “moving proton auroral spot” to a moving flux tube that was created by transient reconnection on the dayside magnetopause and contained relatively high proton densities.
Quantifying the imprint of a severe Hector thunderstorm during ACTIVE/SCOUT-O3 onto the water content in the upper troposphere/lower stratosphere

Abstract The development of a severe Hector thunderstorm that formed over the Tiwi Islands, north of Australia, during the Aerosol and Chemical Transport in Tropical Convection/Stratospheric-Climate Links with Emphasis on the Upper Troposphere and Lower Stratosphere (ACTIVE/SCOUT-O3) field campaign in late 2005, is simulated by the Advanced Research Weather Research and Forecasting (ARW) model and the Met Office Unified Model (UM). The general aim of this paper is to investigate the role of isolated deep convection over the tropics in regulating the water content in the upper troposphere/lower stratosphere (UT/LS). Using a horizontal resolution as fine as 1 km, the numerical simulations reproduce the timing, structure, and strength of Hector fairly well when compared with field campaign observations. The sensitivity of results from ARW to horizontal resolution is investigated by running the model in a large-eddy simulation mode with a horizontal resolution of 250 m. While refining the horizontal resolutio.
Average and unusual locations of the Earth's magnetopause and bow shock

A best-fit ellipse and hyperbola have been calculated to represent several hundred magnetopause and bow-shock positions observed by six Imp spacecraft. Average geocentric distances to the magnetopause and bow shock near the ecliptic plane are 11.0 and 14.6 RE in the sunward direction, 15.1 and 22.8 RE in the dawn meridian, and 15.8 and 27.6 RE in the dusk meridian. The bow-shock hyperbola is oriented in a direction consistent with that expected when the aberration of a radial solar wind is considered. Observed magnetopause crossings agree well with theoretical predictions in the noon meridian plane but fall outside the theoretical boundaries in the dawn-dusk meridian planes. Imp 4 plasma data are used to demonstrate that the solar-wind momentum flux is the prime factor controlling the orbit-to-orbit changes in the boundary positions. Data suggest that the interplanetary-field orientation also affects the distance to the magnetopause boundary, more earthward crossings corresponding to southward fields. Six unusual bow-shock locations up to 22 RE beyond the average position are found to be due to an enhanced standoff distance associated with a low Alfven Mach number. The possibility that the solar wind may have become sub-Alfvenic on July 31, 1967, is suggested.