Miracle-dz/UniFAR-FTUs huggingface dataset:
EXPERIMENTAL INVESTIGATION OF FRICTION BEHAVIOR IN PRE-SLIDING REGIME FOR PNEUMATIC CYLINDER

Friction always presents in pneumatic cylinders and causes difficulties in controlling position and velocity of pneumatic systems. In order to improve the control performace of the pneumatic systems, it is necessary to fully understand behavior of friction in the pneumatic cylinders. So far, dynamic friction behavior of pneumatic cylinders has been investigated but mainly focused on the friction behavior in sliding regime. In pre-sliding regime, friction behavior has not been investigated. In this paper, experimental investigations of friction behavior of a pneumatic cylinder in pre-sliding regime are made. The friction force is calculated from the equation of motion of the piston using the measured values of pressures in the two cylinder chambers and the piston displacement. The pressures are controlled by using two proportional pressure control valve. The friction force versus piston displacement characteristics are measured and analysed under various operating conditions of the applied force and the pressures. Experimental results show that: i) the piston motion in pre-sliding regime exhibits a nonlinear spring behavior; ii) hysteretic behavior with nonlocal memory is verified; iii) the pressures have influence only on the size of the hysteretic loop. These experimental results can be applied to develop a friction model for pneumatic cylinders.
Stability and Hopf Bifurcation in a Prey-Predator System with Disease in the Prey and Two Delays

This paper is concerned with a prey-predator system with disease in the prey and two delays. Local stability of the positive equilibrium of the system and existence of local Hopf bifurcation are investigated by choosing different combinations of the two delays as bifurcation parameters. For further investigation, the direction and the stability of the Hopf bifurcation are determined by using the normal form method and center manifold theorem. Finally, some numerical simulations are given to support the theoretical analysis.
Passive scalar dynamics in turbulent wakes of bodies moving in a linearly stratified medium

A numerical model of passive scalar dynamics in turbulent wakes of bodies of revolution in a linearly stratified medium is constructed. To describe the flow we use a three-dimensional parabolized system of equations of motion, continuity, incompressibility, turbulent energy transport, dissipation rate, averaged concentration and dispersion of passive scalar concentration fluctuations. Computational results demonstrate the behaviour of passive scalar characteristics both for momentumless wake and in the wake behind a towed body.
Ultrafast superconducting single-photon detector

The state-of-the-art of the NbN nanowire superconducting single-photon detector technology (SSPD) is presented. The SSPDs exhibit excellent performance at 2 K temperature: 30% quantum efficiency from visible to infrared, negligible dark count rate, single-photon sensitivity up to 5.6 µm. The recent achievements in the development of GHz counting rate devices with photon-number resolving capability is presented.
Refractive Index Measurement and its Applications

The refractive index of a material is one of the most important optical parameters. In this review article we have discussed different methods and techniques for the measurement of refractive indices of various materials. We have considered the literature of the past two decades from 1980 to 2001 and have shown how the techniques have been developed and improved for the measurement of refractive indices. Some applications of refractive index have also been discussed.
Anthocyanins from Lycium ruthenicum Murray Inhibit HepG2 Cells Growth, Metastasis and Promote Apoptosis and G2/M Phase Cycle Arrest by Activating the AMPK/mTOR Autophagy Pathway

Among the most common malignancies in humans, liver cancer ranks third in terms of mortality in the world. Seeking new anticancer drugs or adjuvant chemotherapy drugs from natural products has attracted the attention of many researchers. Lycium ruthenicum Murray (LR), a health food and traditional Chinese medicine, exerts extensive pharmacological properties, of which anthocyanins are one of the key active components. In this research, we explored the antitumor activity and autophagy regulation mechanism of anthocyanins from Lycium ruthenicum Murray (ALR) in HepG2 cells. Our results found that ALR profoundly reduced the cell viability, clone formation, migration, and invasion and promoted apoptosis and G2/M phase arrest of HepG2 cells in a dose-dependent pattern. Further studies confirmed that ALR treatment significantly increased the number of autophagic vacuoles and autophagosomes, upregulated the expression of Beclin-1, p62, LC3-II/LC3-I, and p-AMPK, and concomitantly downregulated the expression of p-mTOR. When autophagy was inhibited by 3-methyladenine (3-MA), ALR-induced proliferation inhibition, invasion, and migration capabilities, as well as apoptosis rate and G2/M phase arrest, were all reversed, and the activities of key proteins in the AMPK/mTOR pathway were all constrained. In summary, the results presented here indicate that ALR may be effective as a natural antitumor agent by activating AMPK and inhibiting the mTOR autophagy pathway in HepG2 cells.
Polarimetric signatures and hydrometeor classification of West African squall lines

During the AMMA campaign, the Doppler and polarimetric radar Ronsard was deployed in Kopargo, Benin. In the present paper, three squall lines sampled during that period are described. It was the first time this type of system had been observed with a polarimetric radar in the West African region. The strongest case occurred on 28 July 2006, and the others on 12 September and 30 June. The polarimetric characteristics of these systems are described and a hydrometeor classification algorithm is applied in order to identify the microphysics of the systems. Finally, the 3D wind field is retrieved for the 28 July event. The convective part of the squall lines is generally characterized by maxima of reflectivity, differential reflectivity (ZDR), and specific differential phase (KDP). The results of the hydrometeor classification show that the convective region is composed of strong (>30 mm h−1) to moderate rain (5–30 mm h−1) below the melting level, and graupel above. This zone seems to be characterized by relatively strong updraughts (5–10 m s−1), responsible both for the formation of graupel by riming and for the growth of drops due to coalescence. To the rear the systems are characterized by light rain (<5 mm h−1) below and snow or ice crystals above. These regions present downward flow below the melting layer, which prevents drop growth by condensation, consistent with the light rain observed. The stratiform part of these systems can be very non‐uniform, due to the presence of old cells dissipating, associated with moderate rain and thus stronger reflectivities. Copyright © 2010 Royal Meteorological Society
A HÖLDER INEQUALITY FOR NORMS OF POISSONIAN WICK PRODUCTS

An understanding of the second quantization operator of a constant times the identity operator and the Poissonian Wick product, without using the orthogonal Charlier polynomials, is presented first. We use both understanding, with and without the Charlier polynomials, to prove some inequalities about the norms of Poissonian Wick products. These inequalities are the best ones in the case of L1, L2, and L∞ norms. We close the paper with some probabilistic interpretations of the Poissonian Wick product.
On the Rate of Abundance Modifications versus Time in Active Region Plasmas

Four emerging and developing active regions observed on Skylab spectroheliograms (300-600 Å) have been studied over intervals of 3 to 7 days to determine the change in their Mg/Ne abundance ratio. The Mg/Ne abundance ratio is used as a measure of the FIP effect on element abundances in the solar upper atmosphere. Mg/Ne abundance ratios were derived from diagnostic intensity ratios of Mg VI lines at 400 Å relative to adjacent Ne VI lines. Intensity ratios were estimated from the active region images in the Skylab Atlas of Extreme-Ultraviolet Spectroheliograms. The resulting abundance ratios expressed in terms of the FIP bias β (see text) are plotted as a function of elapsed time since emergence. After emergence the newborn region shows photospheric composition: i.e., the abundance ratio of Mg/Ne = 0.296, β = 1. Thereafter, the developing regions show a progressive increase in the Mg/Ne abundance ratio with the value of β reaching after 2 days coronal-type abundances: Mg/Ne = 1.43, β ≈ 4.8. In the later stages, the bias increases to values between 7 and 9 after 3 to 7 days. Some implications of the abundance modifications are briefly discussed.
A generalization of the strict topology

The strict topology f on the space C(X) of bounded real-valued continuous functions on a topological space X was defined, for locally compact X, by Buck (Michigan Math. J. 5 (1958), 95-104). Among other things he showed that (a) C(X) is :-complete, (b) the dual of C(X) under the strict topology is the space of all finite signed regular Borel measures on X, and (c) a Stone-Weierstrass theorem holds for :-closed subalgebras of C(X). In this paper the definition of the strict topology is generalized to cover the case of an arbitrary topological space and these results are established under the following conditions on X: for (a) X is a k-space; for (b) X is completely regular; for (c) X is unrestricted.
Generation of flattop focusing with second order full Poincaré beams

In this paper, the generation of two-dimensional flattop focusing with second order full Poincaré beams under low numerical aperture focusing condition is proposed and experimentally demonstrated by using a liquid crystal spatial light modulator (SLM). Different input beam sizes can be accommodated by conveniently rotating the half-wave plate and adjusting the working distance. Furthermore, the quantization of the phase pattern loaded onto the SLM has been theoretically and experimentally studied, which potentially may lead to the fabrication of a compact versatile flattop beam shaper. High quality flattop profiles with steep edge roll-off can be obtained with this technique.
75-plus years of anisotropy in exploration and reservoir seismics: A historical review of concepts and methods

The idea that the propagation of elastic waves can be anisotropic, i.e., that the velocity may depend on the direction, is about 175 years old. The first steps are connected with the top scientists of that time, people such as Cauchy, Fresnel, Green, and Kelvin. For most of the 19th century, anisotropic wave propagation was studied mainly by mathematical physicists, and the only applications were in crystal optics and crystal elasticity. During these years, important steps in the formal description of the subject were made. At the turn of the 20th century, Rudzki stressed the significance of seismic anisotropy. He studied many of its aspects, but his ideas were not applied. Research in seismic anisotropy became stagnant after his death in 1916. Beginning about 1950, the significance of seismic anisotropy for exploration seismics was studied, mainly in connection with thinly layered media and the resulting transverse isotropy. Very soon it became clear that the effect of layer-induced anisotropy on data ac.
A new finite‐element formulation for electromechanical boundary value problems

In this paper, a new finite‐element formulation for the solution of electromechanical boundary value problems is presented. As opposed to the standard formulation that uses scalar electric potential as nodal variables, this new formulation implements a vector potential from which components of electric displacement are derived. For linear piezoelectric materials with positive definite material moduli, the resulting finite‐element stiffness matrix from the vector potential formulation is also positive definite. If the material is non‐linear in a fashion characteristic of ferroelectric materials, it is demonstrated that a straightforward iterative solution procedure is unstable for the standard scalar potential formulation, but stable for the new vector potential formulation. Finally, the method is used to compute fields around a crack tip in an idealized non‐linear ferroelectric material, and results are compared to an analytical solution. Copyright © 2002 John Wiley & Sons, Ltd.
HIGH-RESOLUTION VERY LARGE ARRAY IMAGING OF SLOAN DIGITAL SKY SURVEY STRIPE 82 AT 1.4 GHz

We present a high-resolution radio survey of the Sloan Digital Sky Survey (SDSS) Southern Equatorial Stripe, a.k. a. Stripe 82. This 1.4 GHz survey was conducted with the Very Large Array primarily in the A-configuration, with supplemental B-configuration data to increase sensitivity to extended structure. The survey has an angular resolution of 1. ″8 and achieves a median rms noise of 52 μJy beam−1 over 92 deg2. This is the deepest 1.4 GHz survey to achieve this large of an area, filling a gap in the phase space between small, deep and large, shallow surveys. It also serves as a pilot project for a larger high-resolution survey with the Expanded Very Large Array. We discuss the technical design of the survey and details of the observations, and we outline our method for data reduction. We present a catalog of 17,969 isolated radio components, for an overall source density of ∼195 sources deg−2. The astrometric accuracy of the data is excellent, with an internal check utilizing multiply observed sources yielding an rms scatter of 0. ″19 in both right ascension and declination. A comparison to the SDSS DR7 Quasar Catalog further confirms that the astrometry is well tied to the optical reference frame, with mean offsets of 0. ″02 ± 0. ″01 in right ascension, and 0. ″01 ± 0. ″02 in declination. A check of our photometry reveals a small, negative CLEAN-like bias on the level of 35 μJy. We report on the catalog completeness, finding that 97% of FIRST-detected quasars are recovered in the new Stripe 82 radio catalog, while faint, extended sources are more likely to be resolved out by the resolution bias. We conclude with a discussion of the optical counterparts to the catalog sources, including 76 newly detected radio quasars. The full catalog as well as a search page and cutout server are available online at http://third.ucllnl. org/cgi-bin/stripe82cutout.
Transport AC loss measurement of a five strand YBCO Roebel cable

Transport AC loss in a 5/2 YBCO Roebel cable (five 2 mm wide strands) with a pitch length of 90 mm is measured over a range of frequencies from 59 to 354 Hz. Five rectangular voltage loops are arranged from pairs of voltage taps attached at one pitch length separation on each strand. There are significant differences in the apparent transport AC loss measured from the different voltage loops at low frequency due to phase shifts in the current in each strand with respect to the phase of the total cable current. The difference in transport AC losses measured from different voltage loops becomes small with increasing frequency, because current is more equally distributed in each strand due to the higher reactance at high frequency. At 354 Hz, results measured with different voltage loops agree well with each other. As theoretically expected, the transport AC losses at different frequencies calculated from the mean value of in-phase voltages measured from the five different voltage loops agree well with each other. At It/Ic = 0.85, the transport AC loss in the 5/2 Roebel cable normalized by the number of strands and square of critical current per strand is around 2.9 times that in a single strand compared to the prediction of five times for a close bundle composed of five conductors. This difference may be due to the transposition of the strands.
X-ray observations of the Ophiuchus, PKS 0745–191 and Cygnus-A clusters of galaxies

Observations are reported of the X-ray emission from three bright clusters of galaxies at low Galactic latitudes: the Ophiuchus, PKS 0745-191, and Cygnus-A clusters. Temperatures and iron abundances are determined from Exosat spectral data. Images of the Ophiuchus cluster show it to have a high central density and a cooling flow. Measurements of a high gas density around PKS 0745-191 and are confirmed, and it is shown that the X-ray emission is centered on the radio galaxy. The PKS 0745-191 cluster is the most distant object for which an abundance has been measured from X-ray spectra. The spectrum of Cygnus-A contains a highly absorbed power-law component that is identified with the nucleus of the radio source.
Evaluation of scaling laws derived from Lie group symmetry methods in zero-pressure-gradient turbulent boundary layers

New scaling laws for turbulent boundary layers recently derived (see Oberlack 2000) using Lie group symmetry methods have been tested against experimental data from the KTH database for zero-pressure-gradient turbulent boundary layers. The most significant new law predicts an exponential variation of the mean velocity defect in the outer (wake) region. It was shown to fit the experimental data very well over a large part of the boundary layer, from the outer part of the overlap region to about half the boundary layer thickness ($\delta_{99}$). In the outermost part of the boundary layer the velocity defect falls more rapidly than predicted by the exponential law. This can partly be attributed to intermittency in that region but the main cause stems from non-parallel effects that are not accounted for in the derivation of the exponential law. The two-point correlation function behaviour in the outer region, where an exponential velocity defect law is observed, was found to be very different from that derived under the assumption of parallel flow. It is found to be plausible that this indeed can be attributed to non-parallel effects. A small modification of the innermost part of the log-layer in the form of an additive constant within the log-function is predicted by the Lie group symmetry method. A qualitative agreement with such a behaviour just below the overlap region was found. The derived scaling law behaviour in the overlap region for the two-point correlation functions was also verified by the experimental data.
Flow-Sound Interaction Mechanisms in the Wake of Two Side-By-Side Cylinders

The phenomenon of flow-excited acoustic resonance, where periodic flow oscillations are enhanced by a resonant sound field, is a design concern in many engineering applications such as in heat exchangers, piping systems, and cavity flows. This study experimentally examines the phenomenon of flow-excited acoustic resonance for two side-by-side cylinders in a duct with cross-flow. This geometry has been investigated for three cylinder spacing ratios, defined as the center-to-center distance between the cylinders normalized by their diameter, of T/D = 1.25, 1.46 and 2.5, and for a range of acoustic pressure amplitudes. Intermediate and small spacing ratios have been given special attention, as these cases have been found to exhibit bistable flow in the wake in the absence of acoustic resonance. Phase-locked PIV measurements reveal that the self-excited sound field produces a strong oscillatory flow pattern in the cylinder wakes, which is symmetric for large spacing ratios and high acoustic amplitudes, but remains bistable for small spacing ratios, even during very intense acoustic resonances. The aeroacoustic sources and sinks within the flow field, computed using Howe's theory of vortex sound, are compared for the range of spacing ratios and acoustic pressure amplitudes examined in this study.
STRENGTH ABILITIES: ASSESSMENT AND SPECIFIC FEATURES OF THE DEVELOPMENT OF ELEMENTARY SCHOOL-AGED KARATE BOYS

The purpose of this study is to determine the age-specific features of the manifestation of differences in the strength fitness of younger grade boys who attend a karate class at the sports and health stage. Materials and methods. The study participants were 57 children who were tested to determine their level of strength abilities. They were divided into four age groups: 7-year-old boys (n=14), 8-year-old boys (n=15), 9-year-old boys (n=15), and 10-year-old boys (n=13). The children and their parents were informed about all the features of the study and gave their consent to participate in the experiment. The children’s technical level corresponded to the student grades of 10th or 9th Kyu (Orange Belt). The solution of the set tasks involved the use of the following research methods: review and analysis of scientific and methodical literature, pedagogical observation, timing of educational tasks, testing of strength abilities, pedagogical ascertaining experiment, methods of mathematical statistics. Results. Statistically significant age-specific differences were observed between the groups of boys aged 7 and 8 in the results of the following tests: push-ups (р=0.0001), 30 second sit-ups (р=0.001), pull-ups and chin-ups (р=0.008), flexed-arm hang (р=0.003), left hand dynamometry (р=0.023), standing long jump (р=0.0001); between the groups of boys aged 8 and 9 in the results of the following tests: 30 second sit-ups (р=0.046), pull-ups and chin-ups (р=0.004), flexed-arm hang (р=0.002); between the groups of boys aged 9 and 10 in the results of the following tests: standing long jump (р=0.014). Conclusions. It was established that the boys have differences in various structural elements that characterize strength indicators. And these differences are in line with the age indicators and technical level of the karatekas.
Nonlinear fluid closure: Three-mode slab ion temperature gradient problem with diffusion

The three-mode slab ion temperature gradient problem was considered. Starting from the drift kinetic equation with nonlinear term and diffusion, the hierarchy of fluid equations up to fourth moment was developed. As a closure, the nonlinear fluid closure by N. Mattor and S. Parker [Phys. Rev. Lett. 79, 3419 (1997)] was applied. Numerical solutions of the system of fluid equations have been obtained and analyzed. The time evolution of electrostatic potential shows that nonlinear fluid closure is able to capture particle trapping, which is important for fusion plasmas. Great attention was paid to studies of the role of diffusion. Diffusion here represents effects of background turbulence and can be described by a Fokker–Planck operator [A. Zagorodny and J. Weiland, Phys. Plasmas 6, 2359 (1999)]. The three wave system can be considered as a system of test waves in a turbulent background. This system can be used to study situations of varying partial coherence.
Average diurnal variation of summer lightning over the Florida Peninsula

Abstract Data derived from a large network of electric field mills have been used to determine the average diurnal variation of lightning in a Florida seacoast environment. These data were obtained at the NASA Kennedy Space Center (KSC) and the Cape Canaveral Air Force Station (CCAFS) during the summers of 1976–78 and 1980 and they show a peak in lightning activity between the hours of 2000 and 2100 GMT or about 3 hours after local solar noon. When the statistics of lightning am compared with the statisfies or thunder on the same day, good agreement is round between the start times and the times of peak activity; however, the thunder stop times tend to Rag the lightning by 1 to 2 hours. The average diurnal variation of cloud-to-ground lightning that was recorded by a network of magnetic diffusion-finders covering the entire South Florida region during the summer of 1978 is in good agreement with the results obtained at KSC and CCAFS and agrees with previous estimates of the time variations in rainfall and.