Miracle-dz/UniFAR-FTUs huggingface dataset:
Fabrication of MgB2 superconducting wires with a hybrid method combining internal-Mg-diffusion and powder-in-tube processes

We have previously reported that the addition of Mg powder to the B powder layer (B layer) of internal-Mg-diffusion (IMD)-processed MgB2 wires can decrease the amount of unreacted B particles, and hence increase the critical current density (Jc). As the amount of Mg powder is increased, the diameter of the central Mg rod must be reduced in order to maintain an overall Mg:B molar ratio of 1:2, corresponding to stoichiometric MgB2. If this ratio is achieved by the Mg powder alone, then the required diameter of the Mg rod is zero, which means that the IMD process becomes the powder-in-tube (PIT) process. A hybrid process intermediate between the IMD and PIT processes is proposed as a new approach for fabricating MgB2 wires. In the present study, the critical current and microstructure of MgB2 wires fabricated using this method are investigated. It is found that the method yields a higher engineering critical current density (Je, = Jc × MgB2 area fraction, where the MgB2 area fraction corresponds to the ratio of the MgB2 cross-sectional area to the total cross-sectional area of the wire) than that for either the IMD or the PIT method. Compared with the IMD method, the MgB2 layer thickness (the thickness of the MgB2 layer in the transverse cross section) is increased and the diameter of the central hole is decreased, thus increasing the MgB2 area fraction The proposed method also achieves a much higher MgB2 layer density, and thus a much higher Jc, than is possible using the PIT method. The combination of these factors leads to the enhanced Je value of MgB2 wires.
Dispersion of longitudinal waves propagating in liquid-filled cylindrical shells

The dispersion of the first two longitudinal wave modes, L(0,1) and L(0,2), was experimentally investigated for a cylindrical shell (such as a pipe or tube) that was completely filled with a liquid. It was observed that the presence of a liquid inside the cylinder dramatically alters the dispersion curve for the L(0,2) mode by dividing (or branching) the curve into approximately equally spaced regions separated by cutoff-type behavior. This branching was attributed to coupling between the unperturbed L(0,2) mode in the shell and the unperturbed longitudinal modes in a liquid cylinder with rigid boundaries, LL(0,2N), where N is an integer. The physical mechanism for the mode coupling was determined to be radial resonances in the combined liquid/pipe system. In time domain, the liquid effects on the dispersion are manifested as a long-duration signal or a series of short-duration pulses, depending on the pulse length of the transmitted signal relative to the reciprocal of the frequency interval between bran.
Amplitude–polarization representation of three-dimensional beams at a dielectric interface

Three-dimensional optical beams incident on a dielectric interface undergo deformations upon reflection and refraction. Within first-order optics these deformations may be interpreted as longitudinal and transverse displacements and deflections of beam axes. In general, these effects are different for TE and TM components of the beam field. The problem of beam reflection and refraction at the interface is formulated and solved in such a manner that the beams are obtained with uniquely defined uniform displacements of their axes in a spatial domain and their spectrum centres in a spectral domain. Additional modifications of the beam polarization state remain generally small and non-uniform throughout the entire beam spectrum. In this context, a special role of polarization states diagonal in the interface plane is indicated.
Auditive and cognitive factors in speech perception by elderly listeners. III. Additional data and final discussion

In a previous study [van Rooij and Plomp, J. Acoust. Soc. Am. 88, 2611–2624 (1990)], it was found that speech‐perception performance in a sample of elderly subjects tested in the laboratory may be largely determined by two statistically independent components: (1) a major component representing the progressive middle‐ to high‐frequency hearing loss with age and (2) a minor component mainly representing a general decrement in cognitive performance. In the present study, a selected subset of tests used in the laboratory study was administered to a group of elderly subjects less likely to participate in laboratory experimentation. The results show that approximately all the systematic variance with respect to speech‐perception performance, as tested by speech‐reception thresholds (SRTs), can be accounted for by the audiogram alone. The implications of the results of the present study and those of earlier ones [van Rooij, Plomp, and Orlebeke, J. Acoust. Soc. Am. 86, 1294–1309 (1989) and van Rooij and Plomp, J.
Temperature and Purity Dependence of the Superconducting Critical Field, H c 2 . III. Electron Spin and Spin-Orbit Effects

A previously obtained solution of the linearized Gor'kov equations for the upper critical magnetic field ${H}_{c2}$ of a bulk type-II superconductor is extended to include the effects of Pauli spin paramagnetism and spin-orbit impurity scattering. To carry out the calculation, it is necessary to introduce an approximation which assumes that spin-orbit scattering is infrequent in comparison with spin-independent scattering. It is found that spin-orbit scattering counteracts the effects of the spin paramagnetism in limiting the critical field and improves agreement between theory and experiment.
Cloud geometry effects on atmospheric solar absorption

A 3D broadband solar radiative transfer scheme is formulated by integrating a Monte Carlo photon transport algorithm with the Fu‐Liou radiation model. It is applied to fields of tropical mesoscale convective clouds and subtropical marine boundary layer clouds that were generated by a 2D cloud-resolving model. The effects of cloud geometry on the radiative energy budget are examined by comparing the full-resolution Monte Carlo results with those from the independent column approximation (ICA) that applies the plane-parallel radiation model to each column. For the tropical convective cloud system, it is found that cloud geometry effects always enhance atmospheric solar absorption regardless of solar zenith angle. In a large horizontal domain (512 km), differences in domainaveraged atmospheric absorption between the Monte Carlo and the ICA are less tha n4Wm 22 in the daytime. However, for a smaller domain (e.g., 75 km) containing a cluster of deep convective towers, domain-averaged absorption can be enhanced by more than 20 W m22. For a subtropical marine boundary layer cloud system during the stratus-to-cumulus transition, calculations show that the ICA works very well for domain-averaged fluxes of the stratocumulus cloud fields even for a very small domain (4.8 km). For the trade cumulus cloud field, the effects of cloud sides and horizontal transport of photons become more significant. Calculations have also been made for both cloud systems including black carbon aerosol and a water vapor continuum. It is found that cloud geometry produces no discernible effects on the absorption enhancement due to the black carbon aerosol and water vapor continuum. The current study indicates that the atmospheric absorption enhancement due to cloud-related 3D photon transport is small. This enhancement could not explain the excess absorption suggested by recent studies.
PLASMA MOTIONS AND HEATING BY MAGNETIC RECONNECTION IN A 2007 MAY 19 FLARE

Based on scanning spectroscopic observations with the Hinode EUV imaging spectrometer, we have found a loop-top hot source, a fast jet nearby, and an inflow structure flowing to the hot source that appeared in the impulsive phase of a long-duration flare at the disk center on 2007 May 19. The hot source observed in Fe xxiii and Fe xxiv emission lines has the electron temperature of 12 MK and density of 1 × 1010 cm−3. It shows excess line broadening, which exceeds the thermal Doppler width by ∼100 km s−1, with a weak redshift of ∼30 km s−1. We have also observed a blueshifted faint jet whose Doppler velocity exceeds 200 km s−1 with an electron temperature of 9 MK. Coronal plasmas with electron temperature of 1.2 MK and density of 2.5 × 109 cm−3 that flow into the loop-top region with a Doppler velocity of 20 km s−1 have been identified in the Fe xii observation. They disappeared near the hot source, possibly by being heated to the hotter faint jet temperature. From the geometrical relationships of these phenomena, we conclude that they provide evidence for magnetic reconnection that occurs near the loop-top region. The estimated reconnection rate is 0.05–0.1, which supports the Petschek-type magnetic reconnection. Further supporting evidence for the presence of the slow-mode and fast-mode MHD shocks in the reconnection geometry is given based on the observed quantities.
Quantum deformations of SU(2)

Explicit representations of two deformations of SU(2), one in the Cartan basis, and one in the Cartesian basis, are constructed. The Cartan deformation subsumes previously known cases, while the Cartesian deformation appears to be new. In the latter case, explicit reversible mappings in terms of representations of SU(2) and a Casimir for the algebra are constructed.
Raman Spectroscopy Investigation of Ice VII and Deuterated Ice VII to 40 GPa. Disorder in Ice VII

New results concerning room temperature Raman spectra of ice VII and deuterated ice VII in the diamond anvil cell, respectively, to 40 and 77 GPa, are reported. Two overlapping lattice translational bands were observed in H2O up to 25 GPa and in D2O up to 38 GPa and two librational bands were observed in D2O only up to 15 GPa. In the v1 vibron mode region three peaks were observed in H2O and D2O samples up to 28 and 40 GPa, respectively. From 40 up to 77 GPa no mode was observed in D2O. Due to the similarity with the spectrum of ice VIII, the Raman spectrum of ice VII indicates a partial ordering which is characterized by short-range correlations. The width of the v1 mode exhibits a minimum around 13 GPa, this is assigned to proton ordering first increasing and then decreasing under pressure.
An experimental study on discharge mechanism of pulsed atmospheric pressure glow discharges

The discharge mechanism of pulsed atmospheric pressure glow discharges excited by the unipolar positive voltage pulses between two parallel plate electrodes with or without one dielectric barrier on the ground electrode in flowing helium has been characterized by nanosecond time resolved optical and electrical measurements. The uniform glow discharges can only be achieved when the voltage pulse duration is less than 1 μs with bare electrodes. With introducing a dielectric barrier on the ground electrode, a model of electrons traveling on the background ions between two discharge events is proposed to explain the discharge mechanism and characteristics in terms of discharge ignition, discharge spatial profile and discharge current amplitude.
An Order Selection Criterion for Testing Goodness of Fit

Abstract The classical problem of assessing the goodness of fit of a postulated parametric distribution is investigated using techniques from nonparametric density estimation. A new test is proposed based on the data-selected order of a Fourier series density estimator. This test has the novel feature of providing an associated nonparametric estimator that can be used to estimate the unknown density when the null hypothesis is rejected. The limiting null distribution of the proposed test statistic is derived, and the test is shown to be consistent against essentially any fixed alternative. Results are reported from a simulation experiment that compared empirical power properties of the new test with those of Cramér-von Mises and data-driven Neyman smooth-type tests.
Combined dye-streak and hydrogen-bubble visual observations of a turbulent boundary layer

The turbulent boundary layer over a flat plate was observed visually using two dye injectors and a normal bubble wire. One dye injector was a standard wall slot; the other one was a small Pitot probe which could be placed anywhere in the flow. The purpose of these experiments was to improve understanding of the relationships between the bursting of low-speed streaks near the wall and the flow field farther away from the wall. On the basis of these observations, it seems that (i) each lift-up is associated with a disturbance which originates in the logarithmic region and is characterized by a mean motion towards the wall, and that (ii) such disturbances are generated by the interaction of an earlier burst from further upstream with the fluid motion in the logarithmic region.
Nuclear Spin Echo Experiments and the Foundations of Statistical Mechanics

The problem of reconciling the irreversibility of thermodynamics with the completely reversible mechanics of the ultimate constituents of the thermodynamical system is examined from an operational viewpoint. The informational nature of entropy is demonstrated, and the famous paradoxes of statistical mechanics, due to Loschmidt and Zermelo, are resolved with its aid. Spin echo experiments are shown to realize the conditions of Loschmidt's reflection paradox, and used to illustrate how reversibility occurs only with perfect “memory” or information storage, while “forgetting” or loss of information implies irreversibility.
The LET Dependence of LiF:Mg,Ti Dosemeters and its Application for LET Measurements in Mixed Radiation Fields

Several types of standard TLDs were irradiated in various fields of high energy heavy ions and the TL emission in the high temperature region (peaks 6 and 7) was analysed in comparison with that of 60 Co radiation. The parameter determined is defined as the high temperature ratio (HTR). Irradiations were carried out in the JINR (Dubna) with fluoride ions in the energy range from 65 to 275 MeV.amu -1 and carbon ions with energies from 100 MeV.amu -1 up to 3650 MeV.amu -1 . Additionally, irradiations with protons (10 and 62 MeV) were performed. The results show the well known decrease of peak 5 efficiency with increasing LET of the absorbed radiation. The LET dependence of the parameter HTR and of the peak 5 efficiency in the range from 0.35 up to 180 keV. μm -1 are presented. Based on these calibrations, the HTR method allows the measurement of the average LET in mixed radiation fields and therefore the estimation of biologically relevant dose. Results from measurements on space station MIR are also presented.
The severe flooding event of January 1996 across north-central Pennsylvania

Abstract The rapid ablation of a snowpack and intense rainfall combined to cause catastrophic flooding across much of the mid-Atlantic region of the United States on 18 and 19 January 1996. This flooding event resulted in as many as 30 fatalities, numerous injuries, and damage estimated at $1.5 billion. The Loyalsock and Lycoming Creek watersheds in northern Pennsylvania were arguably the hardest hit areas in the region, at least from the perspective of fatalities and injuries. This flooding event, which was certainly devastating from a human and economic perspective, also represents an interesting scientific situation in which climatological preconditioning and the occurrence of an unusual synoptic-scale weather event combined to create disastrous results. Before the event, snow fell at record levels across northern Pennsylvania during the late autumn and early winter seasons. By the middle of January 1996, more snow had fallen across the combined watershed region than is expected during an average snowf.
Spectroscopic Monitoring of Comet C/1996 B2 (Hyakutake) with the JCMT and IRAM Radio Telescopes

Molecular radio lines were monitored in comet C/1996 B2 (Hyakutake) from 1996 February 10 to June 23, using the James Clerk Maxwell Telescope and the 30 m telescope and the Plateau de Bure interferometer of the Institut de Radioastronomie Millimétrique. We report on observations of HCN, CH3OH, CO, H2CO, CS, and H2S and on the evolution of their production rates with heliocentric distance (rh), from 1.86 down to 0.24 AU at perihelion. Most production rates increased roughly as r down to 0.6 AU preperihelion. Closer to the Sun, they stalled before decreasing beyond 0.6 AU postperihelion, when observations resumed. The CS/HCN ratio varied as r from 1.2 to 0.24 AU. A rapid increase of the mean gas temperature in the coma is measured, and the gas expansion velocity increased from 0.55 to 1.6 km s-1, as the comet approached the Sun from 1.6 to 0.3 AU. Molecular abundances of the minor species around 1 AU are similar to those observed in other comets, while the CO abundance relative to water is high (≈22%). Coarse mapping was used to check the comet's position and to investigate the density distribution of the molecules within the coma. It provides constraints on the size of the extended source of formaldehyde, found to be between 1.2 and 2 times the scale length of H2CO itself. The density distribution of CS is compatible with its production from the photodissociation of a short-lived molecule such as CS2. The density distribution observed for CO can be mostly explained by a nuclear source.
Radial dust density profiles in small molecular clouds

A new method for determining the radial volume dust density profiles of dark clouds was developed. This method is appliedto co-added IRAS data of 12 small molecular clouds (Bok globules). Raw 60 and 100 μm images are used to generate median filtered backgrounds to be subtracted from the original images. From the resulting differenced images, dust temperature and dust optical depth maps are generated using a single-temperature blackbody model and a dust emissivity proportional to 1/λ. These clouds are resolved at the longest IRAS wavelengths and exhibit both regular shapes and structural simplicity
Coronal and Transition Region Structure in the RS Canum Venaticorum Binaries V711 Tauri, AR Lacertae, and II Pegasi. I. Data Analysis and Emission Measure Distributions

We present a study of the transition regions and coronae of the RS CVn binaries V711 Tau, AR Lac, and II Peg. Archival data from the Extreme Ultraviolet Explorer (EUVE), International Ultraviolet Explorer (IUE), Goddard High-Resolution Spectrograph (GHRS), and a variety of X-ray telescopes have been analyzed and modeled. Emission measure distributions have been determined for the transition region of each system. The upper transition region (6.1 < log Te < 7.4) has been studied using line fluxes from the EUVE. Emission measure distributions for the lower transition region (3.8 < log Te < 5.3) have been found using emission-line fluxes obtained with IUE and the GHRS. Electron densities of ~1.6 × 1011 and ~5 × 1011 cm-3 have been determined at log Te = 7.0 and log Te = 4.7 respectively, using the density-sensitive Fe XXI λ128. 7 and Si III] λ1892 lines. The total pressure (gas + turbulent) is smaller at the lower temperature, indicating that the high- and low-temperature material originates in physically unconnected regions. The emission measure distributions derived from the EUVE line spectra are compared with emission measures found from spectral fits to a variety of low-resolution X-ray spectra, including our reanalysis of archival EXOSAT spectra. Although the emission measure distribution is continuous, both types of analysis lead to two distinct peaks in the high-temperature emission measure distribution, suggesting that there may be two classes of structure in the upper transition region and corona, e.g., two families of loops.
High-order above-threshold ionization of atomic hydrogen using intense, ultrashort laser pulses

High-sensitivity photoelectron energy spectra of atomic hydrogen using strong 50 fs, 630 nm laser fields are investigated. Differences and similarities, especially with respect to the plateau observed recently with rare-gas atoms, are reported. An intensity-dependent study reveals new details for two series of above-threshold ionization peaks which vanish at low energy. In particular, their shift is compatible with the ponderomotive increase of the ionization limit. The angular distributions of the photoelectrons show an angle-dependent red-shift of the spectra with the maximum shift for a polarization of the laser field pointing in the direction of the detector. We propose an explanation for this feature.
Overconvergent Hilbert modular forms

We generalize the construction of the eigencurve by Coleman-Mazur to the setting of totally real fields, and show that a finite slope Hilbert modular eigenform can be deformed into a one parameter family of finite slope eigenforms. The key point is to show the overconvergence of the canonical subgroup and the complete continuity of the U p operator. We deduce this form some general considerations in rigid analytic geometry.
THERMAL BUCKLING ANALYSIS OF ISOTROPIC AND COMPOSITE PLATES WITH A HOLE

Abstract We analyze thermal buckling of both circular isotropic plates and square antisymmetric angle-ply laminates with a hole in the middle, and subject to a uniform temperature rise, by either closed form solution for the former or finite-element method for the latter. Thin-plate theory is used to analyze the isotropic plates. However, a high-order displacement theory including high-order terms along the transverse direction taking into account transverse normal strain is used in the case of laminates. Results for the isotropic plates indicate that in contrast to the reduction in mechanical buckling loads due to the hole, the thermal buckling temperature actually rises as the size of the hole increases, which indicates that the effect on stress reduction exceeds that on stiffness decrease. Results are more complicated for laminated plates, due to anisotropy.
Three-Degree-of-Freedom Model for Galloping. Part I: Formulation

A three‐degree‐of‐freedom model is developed to comprehensively describe and predict different galloping behavior observed on a single iced, electrical transmission line. Interactions are accommodated between a line's plunge, twist, and swing in the along‐wind direction. Eccentricity of the cross section is also considered and the longitudinal static stiffnesses of adjacent spans are included. The initiating conditions for galloping are derived in closed form. For the parameters causing galloping, perturbation techniques are employed to derive the governing bifurcation equations under the assumption of a weak nonlinearity. A total of 10 (one nonresonant and nine internal resonant) plausible cases are considered. Two different time averaging approaches are used for different cases to simplify the algebra in deriving the explicit solutions. Aerodynamic effects are incorporated in the structural stiffness matrix to improve accuracy and to extend the range of application of the perturbation. A robust criterio.
Student perceptions of writing projects in a university differential-equations course

This qualitative study surveyed 102 differential-equations students in order to investigate how students participating in writing projects in university-level mathematics courses perceive the benefits of writing in the mathematics classroom. Based on previous literature on writing in mathematics, students were asked specifically about the benefits of writing projects as a means to explore practical uses of mathematics, deepen content knowledge, and strengthen communication. Student responses indicated an awareness of these benefits, supporting justifications commonly cited by instructors assigning writing projects. Open-ended survey responses highlighted additional themes which students associated with writing in mathematics, including using software programs and technology, working in groups, and stimulating interest in mathematics. This study provides student feedback to support the use of writing projects in mathematics, as well as student input, which can be utilized to strengthen the impact of writing projects in mathematics.