bluuebunny/crossref_metadata_2025_split huggingface dataset:
Novel Mesoporous ZSM-5 Zeolite with Disparate Morphologies Synthesized by a Double Long-alkyl-chain Organosilane Template
Authors: Zhao Fei , Liu Dongliang , Wang Yijiang 
Published: January 2017

AbstractA novel hierarchical ZSM-5 zeolite containing two disparate morphologies was prepared by using a new organosilane surfactant with two long alkyl chains. Main crystal phase arrayed regularly and stacked in dense layers. However, the rest of crystalline phase was shaped like egg tarts.
Application of the Taguchi technique for the optimization of surface roughness and tool life during the milling of Hastelloy C22
Authors: Kıvak Turgay , Mert Şenol 
Published: January 2017

Abstract
In this study, the effects of machining parameters on surface roughness (Ra) and tool life (Tl) were investigated in the milling of Hastelloy C22 alloy with TiAlN-coated carbide inserts. A number of milling experiments were conducted using the L27 (33) Taguchi orthogonal array on a CNC milling machine under different cutting conditions (dry, compressed air and wet). The cutting condition, cutting speed and feed rate were determined as the essential machining parameters. Analysis of variance (ANOVA) and signal-to-noise (S/N) ratio were employed to evaluate the effects of the machining parameters on Ra and Tl, and prediction models were created using quadratic regression analyses. The results revealed that the feed rate and cutting condition were the most influential factors on surface roughness and flank wear. The maximum tool life was achieved under wet cutting condition using a cutting speed of 30 × min−1 and a feed rate of 0.08 mm × rev−1, while the minimum surface roughness value was obtained under wet cutting condition using a cutting speed of 50 m × min−1 and the same feed rate. Using the optimum cutting parameters for Tl (30 m × min−1, 0.08 mm × rev−1), increases of 234 % and 67 % in tool life were observed under wet and compressed air cutting conditions, respectively, compared to the dry cutting condition.
Preparation and properties of a long time durable superhydrophilic titanium dioxide film obtained by a sol-gel process
Authors: Zhang Jianjun , Zeng Hao , Liu Chun , Li Chao , Ma Sude , Lv Guangpu 
Published: January 2017

Abstract
The superhydrophilic phenomenon of titanium dioxide (TiO2) has some potential applications. However, the superhydrophilicity can be obtained only using ultraviolet (UV) light irradiation and cannot be regained conveniently due to the energy band gap of TiO2. In this study, superhydrophilic TiO2 film on a glass substrate was prepared by a simple sol-gel method and the sol was doped with nitrogen, fluorine and polyethylene glycol (PEG). The preparation method was discussed and the film was characterized. Results show that the anatase TiO2 was obtained at about 500 °C, and the redshift of nitrogen-doped film was the largest, whereas the transmittance of fluorine-doped film was increased. The sizes of TiO2 particles in the films are uniform and the films are homogeneous except PEG-doped TiO2. Superhydrophilicity of films doped with PEG can maintain 12 days and can be regained by the irradiation of sunlight.
THE FAINTEST WISE DEBRIS DISKS: ENHANCED METHODS FOR DETECTION AND VERIFICATION
Authors: Patel Rahul I. , Metchev Stanimir A. , Heinze Aren , Trollo Joseph 
Published: January 2017

ABSTRACT
In an earlier study, we reported nearly 100 previously unknown dusty debris disks around Hipparcos main-sequence stars within 75 pc by selecting stars with excesses in individual WISE colors. Here, we further scrutinize the Hipparcos 75 pc sample to (1) gain sensitivity to previously undetected, fainter mid-IR excesses and (2) remove spurious excesses contaminated by previously unidentified blended sources. We improve on our previous method by adopting a more accurate measure of the confidence threshold for excess detection and by adding an optimally weighted color average that incorporates all shorter-wavelength WISE photometry, rather than using only individual WISE colors. The latter is equivalent to spectral energy distribution fitting, but only over WISE bandpasses. In addition, we leverage the higher-resolution WISE images available through the unWISE.me image service to identify contaminated WISE excesses based on photocenter offsets among the W3- and W4-band images. Altogether, we identify 19 previously unreported candidate debris disks. Combined with the results from our earlier study, we have found a total of 107 new debris disks around 75 pc Hipparcos main-sequence stars using precisely calibrated WISE photometry. This expands the 75 pc debris disk sample by 22% around Hipparcos main-sequence stars and by 20% overall (including non-main-sequence and non-Hipparcos stars).
ASPHERICITY, INTERACTION, AND DUST IN THE TYPE II-P/II-L SUPERNOVA 2013EJ IN MESSIER 74
Authors: Mauerhan Jon C. , Van Dyk Schuyler D. , Johansson Joel , Hu Maokai , Fox Ori D. , Wang Lifan , Graham Melissa L. , Filippenko Alexei V. , Shivvers Isaac 
Published: January 2017

ABSTRACT
SN 2013ej is a well-studied core-collapse supernova (SN) that stemmed from a directly identified red supergiant (RSG) progenitor in galaxy M74. The source exhibits signs of substantial geometric asphericity, X-rays from persistent interaction with circumstellar material (CSM), thermal emission from warm dust, and a light curve that appears intermediate between supernovae of Types II-P and II-L. The proximity of this source motivates a close inspection of these physical characteristics and their potential interconnection. We present multiepoch spectropolarimetry of SN 2013ej during the first 107 days and deep optical spectroscopy and ultraviolet through infrared photometry past ∼800 days. SN 2013ej exhibits the strongest and most persistent continuum and line polarization ever observed for a SN of its class during the recombination phase. Modeling indicates that the data are consistent with an oblate ellipsoidal photosphere, viewed nearly edge-on and probably augmented by optical scattering from circumstellar dust. We suggest that interaction with an equatorial distribution of CSM, perhaps the result of binary evolution, is responsible for generating the photospheric asphericity. Relatedly, our late-time optical imaging and spectroscopy show that asymmetric CSM interaction is ongoing, and the morphology of broad Hα emission from shock-excited ejecta provides additional evidence that the geometry of the interaction region is ellipsoidal. Alternatively, a prolate ellipsoidal geometry from an intrinsically bipolar explosion is also a plausible interpretation of the data but would probably require a ballistic jet of radioactive material capable of penetrating the hydrogen envelope early in the recombination phase. Finally, our latest space-based optical imaging confirms that the late interaction-powered light curve dropped below the stellar progenitor level, confirming the RSG star’s association with the explosion.
UNTANGLING THE NEAR-IR SPECTRAL FEATURES IN THE PROTOPLANETARY ENVIRONMENT OF KH 15D
Authors: Arulanantham Nicole A. , Herbst William , Gilmore Martha S. , Cauley P. Wilson , Leggett S. K. 
Published: January 2017

ABSTRACT
We report on Gemini/GNIRS observations of the binary T Tauri system V582 Mon (KH 15D) at three orbital phases. These spectra allow us to untangle five components of the system: the photosphere and magnetosphere of star B, the jet, scattering properties of the ring material, and excess near-infrared (near-IR) radiation previously attributed to a possible self-luminous planet. We confirm an early-K subgiant classification for star B and show that the magnetospheric He i emission line is variable, possibly indicating increased mass accretion at certain times. As expected, the H2 emission features associated with the inner part of the jet show no variation with orbital phase. We show that the reflectance spectrum for the scattered light has a distinctive blue slope and spectral features consistent with scattering and absorption by a mixture of water and methane ice grains in the 1–50 μm size range. This suggests that the methane frost line is closer than ∼5 au in this system, requiring that the grains be shielded from direct radiation. After correcting for features from the scattered light, jet, magnetosphere, and photosphere, we confirm the presence of leftover near-IR light from an additional source, detectable near minimum brightness. A spectral emission feature matching the model spectrum of a 10 M
J, 1 Myr old planet is found in the excess flux, but other expected features from this model are not seen. Our observations, therefore, tentatively support the picture that a luminous planet is present within the system, although they cannot yet be considered definitive.
DIFFERENCES BETWEEN RADIO-LOUD AND RADIO-QUIET γ-RAY PULSARS AS REVEALED BY FERMI
Authors: Hui C. Y. , Lee Jongsu , Takata J. , Ng C. W. , Cheng K. S. 
Published: January 2017

ABSTRACT
By comparing the properties of non-recycled radio-loud γ-ray pulsars and radio-quiet γ-ray pulsars, we have searched for the differences between these two populations. We found that the γ-ray spectral curvature of radio-quiet pulsars can be larger than that of radio-loud pulsars. Based on the full sample of non-recycled γ-ray pulsars, their distributions of the magnetic field strength at the light cylinder are also found to be different. We note that this might result from an observational bias. By reexamining the previously reported difference of γ-ray-to-X-ray flux ratios, we found that the significance can be hampered by their statistical uncertainties. In the context of the outer gap model, we discuss the expected properties of these two populations and compare with the possible differences that are identified in our analysis.
A CHALLENGING VIEW OF THE 2015 SUMMER V404 CYG OUTBURST AT HIGH ENERGY WITH INTEGRAL/SPI: THE FINALE*
Authors: Jourdain Elisabeth , Roques Jean-Pierre , Rodi James 
Published: January 2017

ABSTRACT
During its strong outburst of 2015 June/July, the X-ray transient V404 Cygni (=GS2023+338) was observed up to a level of 50 Crab in the hard X-ray domain. We focus here on a particularly intense episode preceeding a definitive decline of the source activity. We benefit from large signal-to-noise ratios to investigate the source spectral variability, on a timescale of five minutes. A hardness–intensity study of three broad bands reveals clearly different behaviors at low and high energy (below and above ∼100 keV). In particular, on two occasions, the source intensity varies by a factor of 3–4 in amplitude while keeping the same spectral shape. On the other hand, at the end of the major flare, the emission presents a clear anticorrelation between flux and hardness. These behaviors strongly suggest the presence of two spectral components related to emission processes varying in a largely independent way. The first component (E < 100–150 keV) is classically identified with a Comptonizing thermal electron population, and requires either an unusual seed photon population or a specific geometry with strong absorbing/reflecting material. The second component is modeled by a cutoff power-law, which could correspond to a second hotter Comptonizing population or another mechanism (synchrotron, non-thermal Comptonization...). In the framework of such a model, hardness–intensity and flux–flux diagrams clearly demonstrate that the source evolution follows a well-organized underlying scheme. They reveal unique information about the hard X-ray emission processes and connections between them.
SPECTRAL-TIMING ANALYSIS OF THE LOWER kHz QPO IN THE LOW-MASS X-RAY BINARY AQUILA X-1
Authors: Troyer Jon S. , Cackett Edward M. 
Published: January 2017

ABSTRACT
Spectral-timing products of kilohertz quasi-periodic oscillations (kHz QPOs) in low-mass X-ray binary (LMXB) systems, including energy- and frequency-dependent lags, have been analyzed previously in 4U 1608-52, 4U 1636-53, and 4U 1728-34. Here, we study the spectral-timing properties of the lower kHz QPO of the neutron star LMXB Aquila X-1 for the first time. We compute broadband energy lags as well as energy-dependent lags and the covariance spectrum using data from the Rossi X-ray Timing Explorer. We find characteristics similar to those of previously studied systems, including soft lags of ∼30 μs between the 3.0–8.0 keV and 8.0–20.0 keV energy bands at the average QPO frequency. We also find lags that show a nearly monotonic trend with energy, with the highest-energy photons arriving first. The covariance spectrum of the lower kHz QPO is well fit by a thermal Comptonization model, though we find a seed photon temperature higher than that of the mean spectrum, which was also seen in Peille et al. and indicates the possibility of a composite boundary layer emitting region. Lastly, we see in one set of observations an Fe K component in the covariance spectrum at 2.4-σ confidence, which may raise questions about the role of reverberation in the production of lags.
The Size Evolution of Star-forming Galaxies since z ∼ 7 Using ZFOURGE
Authors: Allen Rebecca J. , Kacprzak Glenn G. , Glazebrook Karl , Labbé Ivo , Tran Kim-Vy H. , Spitler Lee R. , Cowley Michael , Nanayakkara Themiya , Papovich Casey , Quadri Ryan , Straatman Caroline M. S. , Tilvi Vithal , van Dokkum Pieter 
Published: January 2017

Abstract
For the first time, we present the size evolution of a mass-complete (log(M
*/M
⊙) > 10) sample of star-forming galaxies over redshifts z = 1–7, selected from the FourStar Galaxy Evolution Survey. Observed H-band sizes are measured from the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) Hubble Space Telescope (HST)/F160W imaging. Distributions of individual galaxy masses and sizes illustrate that a clear mass−size relation exists up to z ∼ 7. At z ∼ 7, we find that the average galaxy size from the mass−size relation is more compact at a fixed mass of log(M
*/M
⊙) = 10.1, with

kpc, than at lower redshifts. This is consistent with our results from stacking the same CANDELS HST/F160W imaging, when we correct for galaxy position angle alignment. We find that the size evolution of star-forming galaxies is well fit by a power law of the form

kpc, which is consistent with previous works for normal star-formers at 1 < z < 4. In order to compare our slope with those derived Lyman break galaxy studies, we correct for different IMFs and methodology and find a slope of −0.97 ± 0.02, which is shallower than that reported for the evolution of Lyman break galaxies (LBGs) at z > 4 (

). Therefore, we conclude the LBGs likely represent a subset of highly star-forming galaxies that exhibit rapid size growth at z > 4.
HCV Genotype-1 Subtypes and Resistance-Associated Substitutions in Drug-Naive and in Direct-Acting Antiviral Treatment Failure Patients
Authors: Gozlan Yael , Ben-Ari Ziv , Moscona Roy , Shirazi Rachel , Rakovsky Aviya , Kabat Arij , Veizman Ella , Berdichevski Tania , Weiss Peretz , Cohen-Ezra Oranit , Lurie Yoav , Gafanovich Inna , Braun Marius , Cohen-Naftaly Michal , Shlomai Amir , Shibolet Oren , Zigmond Ehud , Zuckerman Eli , Carmiel-Haggai Michal , Nimer Assy , Hazzan Rawi , Maor Yaakov , Kitay-Cohen Yona , Shemer-Avni Yonat , Kra-Oz Zipi , Schreiber Licita , Peleg Ofer , Sierra Saleta , Harrigan P Richard , Mendelson Ella , Mor Orna 
Published: January 2017

Background Direct-acting antiviral (DAA) treatment regimens and response rates of patients with HCV genotype-1 (GT1) are currently considered subtype-dependent. Identification of clinically relevant resistance-associated substitutions (RASs) in the NS3 and NS5A proteins at baseline and in DAA failures, may also impact clinical decisions. Methods In a multicentre cohort study ( n=308), NS3 or NS5B sequencing ( n=248) was used to discriminate between GT1 subtypes. The correlation between baseline NS3 and NS5A RASs on the 12-week sustained virological response (SVR12) rates of 160 of the patients treated with second-generation DAAs was also assessed. Post-treatment resistance analysis was performed on samples from 58 patients exhibiting DAA virological failure. Results GT1a, GT1b and GT1d subtypes were identified in 23.0%, 75.4% and 1.2% of tested samples. GT1b was most prevalent (97.7%, 128/131) among patients born in the former Soviet Union. The Q80K NS3 RAS was identified in 17.5% (10/57) of the GT1a carriers, most of whom were Israeli-born. NS3 and NS5A baseline RASs showed a negligible correlation with SVR12 rates. Treatment-emergent RASs were observed among 8.9% (4/45) and 76.9% (10/13) of first- and second-generation DAA failures, respectively, with D168V/E (NS3), Y93H and L31M (NS5A) being the most prevalent mutations. Conclusions NS3 sequencing analysis can successfully discriminate between GT1 subtypes and identify NS3 amino acid substitutions. While pre-treatment NS3 and NS5A RASs marginally affect second-generation DAA SVR12 rates, post-treatment resistance analysis should be considered prior to re-therapy.
A High-Accuracy Mechanical Quadrature Method for Solving the Axisymmetric Poisson's Equation
Authors: Li Hu , Huang Jin 
Published: January 2017

AbstractIn this article, we consider the numerical solution for Poisson's equation in axisymmetric geometry. When the boundary condition and source term are axisymmetric, the problem reduces to solving Poisson's equation in cylindrical coordinates in the two-dimensional (r,z) region of the original three-dimensional domain S. Hence, the original boundary value problem is reduced to a two-dimensional one. To make use of the Mechanical quadrature method (MQM), it is necessary to calculate a particular solution, which can be subtracted off, so that MQM can be used to solve the resulting Laplace problem, which possesses high accuracy order and low computing complexities. Moreover, the multivariate asymptotic error expansion of MQM accompanied with for all mesh widths hi is got. Hence, once discrete equations with coarse meshes are solved in parallel, the higher accuracy order of numerical approximations can be at least by the splitting extrapolation algorithm (SEA). Meanwhile, a posteriori asymptotic error estimate is derived, which can be used to construct self-adaptive algorithms. The numerical examples support our theoretical analysis.
Robust Semi-Discrete and Fully Discrete Hybrid Stress Finite Element Methods for Elastodynamic Problems
Authors: Xu Xiaojing , Xie Xiaoping 
Published: January 2017

AbstractThis paper analyzes semi-discrete and fully discrete hybrid stress quadrilateral finite element methods for 2-dimensional linear elastodynamic problems. The methods use a 4 node hybrid stress quadrilateral element in the space discretization. In the fully discrete scheme, an implicit second-order scheme is adopted in the time discretization. We derive optimal a priori error estimates for the two schemes and an unconditional stability result for the fully discrete scheme. Numerical experiments confirm the theoretical results.
On the Generation of Instability Tollmien-Schlichting Waves by Free-Stream Turbulence
Authors: Shen Luyu , Lu Changgen 
Published: January 2017

AbstractThe beginning of the transition from the laminar to a turbulent flow is usually the generation of instability Tollmien-Schlichting (T-S) waves in the boundary layer. Previously, most numerical and experimental researches focused on generating instability T-S waves through the external disturbances such as acoustic waves and vortical disturbances interacting with wall roughness or at the leading-edge of flatplate, whereas only a few paid attention to the excitation of the T-S waves directly by free-stream turbulence (FST). In this study, the generating mechanism of the temporal mode T-S waves under free-stream turbulence is investigated by using direct numerical simulation (DNS) and fast Fourier transform. Wave packets superposed by a group of stability, neutral and instability T-S waves are discovered in the boundary layer. In addition, the relation between the amplitude of the imposed free-stream turbulence and the amplitude of the excited T-S wave is also obtained.
An Immersed Finite Element Method for the Elasticity Problems with Displacement Jump
Authors: Kyeong Daehyeon , Kwak Do Young 
Published: January 2017

AbstractIn this paper, we propose a finite element method for the elasticity problems which have displacement discontinuity along the material interface using uniform grids. We modify the immersed finite element method introduced recently for the computation of interface problems having homogeneous jumps [20, 22]. Since the interface is allowed to cut through the element, we modify the standard Crouzeix-Raviart basis functions so that along the interface, the normal stress is continuous and the jump of the displacement vector is proportional to the normal stress. We construct the broken piecewise linear basis functions which are uniquely determined by these conditions. The unknowns are only associated with the edges of element, except the intersection points. Thus our scheme has fewer degrees of freedom than most of the XFEM type of methods in the existing literature [1,8,13]. Finally, we present numerical results which show optimal orders of convergence rates.
Hill-Climbing Algorithm with a Stick for Unconstrained Optimization Problems
Authors: Huang Yunqing , Jiang Kai 
Published: January 2017

AbstractInspired by the behavior of the blind for hill-climbing using a stick to detect a higher place by drawing a circle, we propose a heuristic direct search method to solve the unconstrained optimization problems. Instead of searching a neighbourhood of the current point as done in the traditional hill-climbing, or along specified search directions in standard direct search methods, the new algorithm searches on a surface with radius determined by the motion of the stick. The significant feature of the proposed algorithm is that it only has one parameter, the search radius, which makes the algorithm convenient in practical implementation. The developed method can shrink the search space to a closed ball, or seek for the final optimal point by adjusting search radius. Furthermore our algorithm possesses multi-resolution feature to distinguish the local and global optimum points with different search radii. Therefore, it can be used by itself or integrated with other optimization methods flexibly as a mathematical optimization technique. A series of numerical tests, including high-dimensional problems, have been well designed to demonstrate its performance.
The effect of shell secretion rate on Mg / Ca and Sr / Ca ratios in biogenic calcite as observed in a belemnite rostrum
Authors: Ullmann Clemens Vinzenz , Pogge von Strandmann Philip A. E. 
Published: January 2017

Abstract. Isotopic ratios and concentrations of the alkaline earth metals Mg and Sr in biogenic calcite are of great importance as proxies for environmental parameters. In particular, the Mg / Ca ratio as a temperature proxy has had considerable success. It is often hard to determine, however, which parameter ultimately controls the concentration of these elements in calcite. Here, multiple Mg / Ca and Sr / Ca transects through a belemnite rostrum of Passaloteuthis bisulcata (Blainville, 1827) are used to isolate the effect of calcite secretion rate on incorporation of Mg and Sr into the calcite. With increasing calcite secretion rate Mg / Ca ratios decrease and Sr / Ca ratios in the rostrum increase. In the studied specimen this effect is found to be linear for both element ratios over a calcite secretion rate increase of ca. 150 %. Mg / Ca ratios and Sr / Ca ratios show a linear co-variation with increasing relative growth rate, where a 100 % increase in growth rate leads to a (8.1 ± 0.9) % depletion in Mg and a (5.9 ± 0.7) % enrichment in Sr. The magnitude of the calcite secretion rate effect on Mg is (37 ± 4) % greater than that on Sr. These findings are qualitatively confirmed by a geochemical transect through a second rostrum of Passaloteuthis sp. Growth rate effects are well defined in rostra of Passaloteuthis, but only account for a minor part of chemical heterogeneity. Biasing effects on palaeoenvironmental studies can be minimized by informed sampling, whereby the apex and apical line of the rostrum are avoided.