bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microstructure, wear and friction behavior of AISI 1045 steel surfaces coated with mechanically alloyed Fe16Mo2C0.25Mn/Al2O3-3TiO2 powders
Authors: Özel Cihan , Akgün Gökçen , Gürgenc Turan 
Published: October 2017

Abstract
The surface of AISI 1045 steel was coated using the flame spray technique. Iron-based superalloy (Fe16Mo2C0.25Mn) powders were used as matrix material and a mixture of mechanically alloyed 10 wt.-% Fe16Mo2C0.25Mn and 90 wt.-% Al2O3–3TiO2 powders was used as reinforcing material. The mechanical alloying process was performed by milling with an attritor for 60 hours. The coating material comprised of a mixture of the matrix (Fe16Mo2C0.25Mn) powder and mechanically alloyed reinforcing powders at varying rates of 5, 10 and 15 %, respectively. The microstructure, microhardness, adhesive wear behaviors and the coefficients of friction of the coated specimens were examined. It was observed that defects increased and cracks formed on the interface, depending on the increase in the reinforcing ratio. It was determined that the coefficient of friction and wear loss increased by the increasing load in all specimens. The minimum wear loss was observed for the specimen with 10 % reinforcement and the maximum wear loss was observed for the specimen with 15 % reinforcement. The highest average coefficient of friction by the applied load was obtained for the coating with 10 % reinforcement and the lowest average coefficient of friction was obtained for the specimen with 5 % reinforcement.
The Fragmentation Criteria in Local Vertically Stratified Self-gravitating Disk Simulations
Authors: Baehr Hans , Klahr Hubert , Kratter Kaitlin M. 
Published: October 2017

Abstract
Massive circumstellar disks are prone to gravitational instabilities, which trigger the formation of spiral arms that can fragment into bound clumps under the right conditions. Two-dimensional simulations of self-gravitating disks are useful starting points for studying fragmentation because they allow high-resolution simulations of thin disks. However, convergence issues can arise in 2D from various sources. One of these sources is the 2D approximation of self-gravity, which exaggerates the effect of self-gravity on small scales when the potential is not smoothed to account for the assumed vertical extent of the disk. This effect is enhanced by increased resolution, resulting in fragmentation at longer cooling timescales β. If true, it suggests that the 3D simulations of disk fragmentation may not have the same convergence problem and could be used to examine the nature of fragmentation without smoothing self-gravity on scales similar to the disk scale height. To that end, we have carried out local 3D self-gravitating disk simulations with simple β cooling with fixed background irradiation to determine if 3D is necessary to properly describe disk fragmentation. Above a resolution of ∼40 grid cells per scale height, we find that our simulations converge with respect to the cooling timescale. This result converges in agreement with analytic expectations which place a fragmentation boundary at β
crit = 3.
Stripped Elliptical Galaxies as Probes of ICM Physics. III. Deep Chandra Observations of NGC 4552: Measuring the Viscosity of the Intracluster Medium
Authors: Kraft R. P. , Roediger E. , Machacek M. , Forman W. R. , Nulsen P. E. J. , Jones C. , Churazov E. , Randall S. , Su Y. , Sheardown A. 
Published: October 2017

Abstract
We present results from a deep (200 ks) Chandra observation of the early-type galaxy NGC 4552 (M89), which is falling into the Virgo cluster. Previous shallower X-ray observations of this galaxy showed a remnant gas core, a tail to the South of the galaxy, and twin “horns” attached to the northern edge of the gas core. In our deeper data, we detect a diffuse, low surface brightness extension to the previously known tail, and measure the temperature structure within the tail. We combine the deep Chandra data with archival XMM-Newton observations to put a strong upper limit on the diffuse emission of the tail out to a large distance (10× the radius of the remnant core) from the galaxy center. In our two previous papers, we presented the results of hydrodynamical simulations of ram pressure stripping specifically for M89 falling into the Virgo cluster and investigated the effect of intracluster medium (ICM) viscosity. In this paper, we compare our deep data with our specifically tailored simulations and conclude that the observed morphology of the stripped tail in NGC 4552 is most similar to the inviscid models. We conclude that, to the extent the transport processes can be simply modeled as a hydrodynamic viscosity, the ICM viscosity is negligible. More generally, any micro-scale description of the transport processes in the high-β plasma of the cluster ICM must be consistent with the efficient mixing observed in the stripped tail on macroscopic scales.
GCM Simulations of Unstable Climates in the Habitable Zone
Authors: Paradise Adiv , Menou Kristen 
Published: October 2017

Abstract
It has recently been proposed that Earth-like planets in the outer regions of the habitable zone experience unstable climates, repeatedly cycling between glaciated and deglaciated climatic states. While this result has been confirmed and also extended to explain early Mars climate records, all existing work relies on highly idealized low-dimensional climate models. Here, we confirm that the phenomenology of climate cycles remains in 3D Earth climate models with considerably more degrees of freedom. To circumvent the computational barrier of integrating climate on Gyr timescales, we implement a hybrid 0D-3D integrator that uses a general circulation model (GCM) as a short relaxation step along a long evolutionary climate sequence. We find that GCM climate cycles are qualitatively consistent with reported low-dimensional results. This establishes on a firmer ground the notion that outer habitable zone planets may be preferentially found in transiently glaciated states.
Flare Ribbons Approach Observed by the Interface Region Imaging Spectrograph and the Solar Dynamics Observatory
Authors: Li Ting , Zhang Jun , Hou Yijun 
Published: October 2017

Abstract
We report flare ribbons approach (FRA) during a multiple-ribbon M-class flare on 2015 November 4 in NOAA AR 12443, obtained by the Interface Region Imaging Spectrograph and the Solar Dynamics Observatory. The flare consisted of a pair of main ribbons and two pairs of secondary ribbons. The two pairs of secondary ribbons were formed later than the appearance of the main ribbons, with respective time delays of 15 and 19 minutes. The negative-polarity main ribbon spread outward faster than the first secondary ribbon with the same polarity in front of it, and thus the FRA was generated. Just before their encounter, the main ribbon was darkening drastically and its intensity decreased by about 70% in 2 minutes, implying the suppression of main-phase reconnection that produced two main ribbons. The FRA caused the deflection of the main ribbon to the direction of secondary ribbon with a deflection angle of about 60°. A post-approach arcade was formed about 2 minutes later and the downflows were detected along the new arcade with velocities of 35–40 km s−1, indicative of the magnetic restructuring during the process of FRA. We suggest that there are three topological domains with footpoints outlined by the three pairs of ribbons. Close proximity of these domains leads to deflection of the ribbons, which is in agreement with the magnetic field topology.
Stacked Average Far-infrared Spectrum of Dusty Star-forming Galaxies from the Herschel/SPIRE Fourier Transform Spectrometer∗
Authors: Wilson Derek , Cooray Asantha , Nayyeri Hooshang , Bonato Matteo , Bradford Charles M. , Clements David L. , De Zotti Gianfranco , Díaz-Santos Tanio , Farrah Duncan , Magdis Georgios , Michałowski Michał J. , Pearson Chris , Rigopoulou Dimitra , Valtchanov Ivan , Wang Lingyu , Wardlow Julie 
Published: October 2017

Abstract
We present stacked average far-infrared spectra of a sample of 197 dusty star-forming galaxies (DSFGs) at

using about 90% of the Herschel Space Observatory SPIRE Fourier Transform Spectrometer (FTS) extragalactic data archive based on 3.5 years of science operations. These spectra explore an observed-frame 447–1568 GHz frequency range, allowing us to observe the main atomic and molecular lines emitted by gas in the interstellar medium. The sample is subdivided into redshift bins, and a subset of the bins are stacked by infrared luminosity as well. These stacked spectra are used to determine the average gas density and radiation field strength in the photodissociation regions (PDRs) of DSFGs. For the low-redshift sample, we present the average spectral line energy distributions of CO and H2O rotational transitions and consider PDR conditions based on observed [C i] 370 and 609 μm, and CO (7-6) lines. For the high-z (

) sample, PDR models suggest a molecular gas distribution in the presence of a radiation field that is at least a factor of 103 larger than the Milky Way and with a neutral gas density of roughly

–

cm−3. The corresponding PDR models for the low-z sample suggest a UV radiation field and gas density comparable to those at high-z. Given the challenges in obtaining adequate far-infrared observations, the stacked average spectra we present here will remain the measurements with the highest signal-to-noise ratio for at least a decade and a half until the launch of the next far-infrared facility.
Halo Intrinsic Alignment: Dependence on Mass, Formation Time, and Environment
Authors: Xia Qianli , Kang Xi , Wang Peng , Luo Yu , Yang Xiaohu , Jing Yipeng , Wang Huiyuan , Mo Houjun 
Published: October 2017

Abstract
In this paper we use high-resolution cosmological simulations to study halo intrinsic alignment and its dependence on mass, formation time, and large-scale environment. In agreement with previous studies using N-body simulations, it is found that massive halos have stronger alignment. For the first time, we find that for a given halo mass older halos have stronger alignment and halos in cluster regions also have stronger alignment than those in filaments. To model these dependencies, we extend the linear alignment model with inclusion of halo bias and find that the halo alignment with its mass and formation time dependence can be explained by halo bias. However, the model cannot account for the environment dependence, as it is found that halo bias is lower in clusters and higher in filaments. Our results suggest that halo bias and environment are independent factors in determining halo alignment. We also study the halo alignment correlation function and find that halos are strongly clustered along their major axes and less clustered along the minor axes. The correlated halo alignment can extend to scales as large as 100 h
−1 Mpc, where its feature is mainly driven by the baryon acoustic oscillation effect.
Isothermal Bondi Accretion in Jaffe and Hernquist Galaxies with a Central Black Hole: Fully Analytical Solutions
Authors: Ciotti Luca , Pellegrini Silvia 
Published: October 2017

Abstract
One of the most active fields of research of modern-day astrophysics is that of massive black hole formation and coevolution with the host galaxy. In these investigations, ranging from cosmological simulations, to semi-analytical modeling, to observational studies, the Bondi solution for accretion on a central point-mass is widely adopted. In this work we generalize the classical Bondi accretion theory to take into account the effects of the gravitational potential of the host galaxy, and of radiation pressure in the optically thin limit. Then, we present the fully analytical solution, in terms of the Lambert–Euler W-function, for isothermal accretion in Jaffe and Hernquist galaxies with a central black hole. The flow structure is found to be sensitive to the shape of the mass profile of the host galaxy. These results and the formulae that are provided, most importantly, the one for the critical accretion parameter, allow for a direct evaluation of all flow properties, and are then useful for the abovementioned studies. As an application, we examine the departure from the true mass accretion rate of estimates obtained using the gas properties at various distances from the black hole, under the hypothesis of classical Bondi accretion. An overestimate is obtained from regions close to the black hole, and an underestimate outside a few Bondi radii; the exact position of the transition between the two kinds of departure depends on the galaxy model.
ALMA Shows that Gas Reservoirs of Star-forming Disks over the Past 3 Billion Years Are Not Predominantly Molecular
Authors: Cortese Luca , Catinella Barbara , Janowiecki Steven 
Published: October 2017

Abstract
Cold hydrogen gas is the raw fuel for star formation in galaxies, and its partition into atomic and molecular phases is a key quantity for galaxy evolution. In this Letter, we combine Atacama Large Millimeter/submillimeter Array and Arecibo single-dish observations to estimate the molecular-to-atomic hydrogen mass ratio for massive star-forming galaxies at z ∼ 0.2 extracted from the HIGHz survey, i.e., some of the most massive gas-rich systems currently known. We show that the balance between atomic and molecular hydrogen in these galaxies is similar to that of local main-sequence disks, implying that atomic hydrogen has been dominating the cold gas mass budget of star-forming galaxies for at least the past three billion years. In addition, despite harboring gas reservoirs that are more typical of objects at the cosmic noon, HIGHz galaxies host regular rotating disks with low gas velocity dispersions suggesting that high total gas fractions do not necessarily drive high turbulence in the interstellar medium.
Detection of Three-minute Oscillations in Full-disk Lyα Emission during a Solar Flare
Authors: Milligan Ryan O. , Fleck Bernhard , Ireland Jack , Fletcher Lyndsay , Dennis Brian R. 
Published: October 2017

Abstract
In this Letter we report the detection of chromospheric 3-minute oscillations in disk-integrated EUV irradiance observations during a solar flare. A wavelet analysis of detrended Lyα (from GOES/EUVS) and Lyman continuum (from Solar Dynamics Observatory (SDO)/EVE) emission from the 2011 February 15 X-class flare (SOL2011-02-15T01:56) revealed a ∼3 minute period present during the flare’s main phase. The formation temperature of this emission locates this radiation at the flare’s chromospheric footpoints, and similar behavior is found in the SDO/Atmospheric Imaging Assembly 1600 and 1700 Å channels, which are dominated by chromospheric continuum. The implication is that the chromosphere responds dynamically at its acoustic cutoff frequency to an impulsive injection of energy. Since the 3-minute period was not found at hard X-ray (HXR) energies (50–100 keV) in Reuven Ramaty High Energy Solar Spectroscopic Imager data we can state that this 3-minute oscillation does not depend on the rate of energization of non-thermal electrons. However, a second period of 120 s found in both HXR and chromospheric lightcurves is consistent with episodic electron energization on 2-minute timescales. Our finding on the 3-minute oscillation suggests that chromospheric mechanical energy should be included in the flare energy budget, and the fluctuations in the Lyα line may influence the composition and dynamics of planetary atmospheres during periods of high activity.
Off-axis Prompt X-Ray Transients from the Cocoon of Short Gamma-Ray Bursts
Authors: Lazzati Davide , López-Cámara Diego , Cantiello Matteo , Morsony Brian J. , Perna Rosalba , Workman Jared C. 
Published: October 2017

Abstract
We present the results of numerical simulations of the prompt emission of short-duration gamma-ray bursts. We consider emission from the relativistic jet, the mildly relativistic cocoon, and the non-relativistic shocked ambient material. We find that the cocoon material is confined between off-axis angles

and gives origin to X-ray transients with a duration of a few to ∼10 s, delayed by a few seconds from the time of the merger. We also discuss the distance at which such transients can be detected, finding that it depends sensitively on the assumptions that are made about the radiation spectrum. Purely thermal cocoon transients are detectable only out to a few Mpc, while Comptonized transients can instead be detected by the Fermi Gamma-ray Burst Monitor (GBM) out to several tens of Mpc.
A busca por financiamento da inovação na indústria da construção civil – Rio de Janeiro
Authors: Gomes Sílvia Valeriano , Dos Santos João Alberto Neves , Terra Branca Regina Cantisano dos Santos e Silva Riscado 
Published: October 2017

A necessidade de se inovar está cada vez mais evidenciada como sendo caminho, pelo qual os países têm a oportunidade de agregar valor as suas respectivas economias. Além de ser necessário à resolução de questões como, o alto volume de resíduos sólidos na construção civil. Para isso existe a necessidade de fomento governamental como forma de indução do processo de inovação. Objetivou-se identificar as dificuldades de acesso ao financiamento junto à agência de fomento governamental, no caso, a Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de janeiro - FAPERJ. Através do mapeamento dos editais lançados de 2010 a 2014 e seus respectivos projetos contemplados, foi possível obter a classificação dos projetos por área de conhecimento, o que tornou possível averiguar que a Engenharia Civil obteve financiamento junto à Agência de apenas 1,12% do total projetos aprovados. Foi aplicado um survey conseguindo mapear 12 Fatores críticos, que dificultam o acesso ao financiamento no processo. A confiabilidade encontrada foi de 0,867, na validação do conteúdo encontrou-se uma perda de 6,10% onde consta os 12 Fatores críticos validos. Na validação do constructo, tem-se o Teste de KMO com 0,837 e o teste de esfericidade dei Bartlett’s 0,000. Através da análise dos carregamentos dos fatores críticos comprovou a existência de um único constructo, sendo este composto por três subconstructos (Problemas inerentes à Agência de fomento; Problemas relacionados aos profissionais; e Problemas referentes aos Editais – Agência e Legislação).
Análise crítica da gestão por competências em universidades federais
Authors: Perseguino Silvana Aparecida , Alves Pedro Wilson José 
Published: October 2017

Este artigo desenvolve uma reflexão sobre o estágio de adoção do modelo de gestão por competências em universidades federais, pautada em revisão de literatura sobre o tema e em resultados da primeira etapa de pesquisa envolvendo a perspectiva dos gestores da área de gestão de pessoas dessas instituições. De uma amostra de cinquenta universidades, identificou-se oito instituições que adotaram o modelo de gestão por competências, cuja maioria contempla o modelo no nível estratégico de gestão. Quanto aos referenciais teóricos adotados por essas instituições, alguns são recorrentes e talvez indiquem uma possível aderência com a esfera pública. Mesmo assim, na amostra ficou evidente que o modelo de gestão por competências, apesar de não consolidado no contexto das universidades federais, está em construção e, na visão dos gestores, alguns desafios precisam ser superados relacionados especialmente no que tange a: cultura organizacional, pessoal qualificado, limitações da legislação no setor público e limitações orçamentárias para adequação de sistemas. Também se identificou que o processo de expansão das universidades federais requer novos modelos de gestão e a gestão por competências se insere nessa modalidade.
Ecosystem services in Norway
Authors: Skre Oddvar 
Published: October 2017

The present study is reviewing public reports and research articles in order to estimate and validate ecosystem services in Norway, and investigate conflicts between stakeholders representing different ecosystem services, by means of direct and indirect methods, for different main ecosystem categories,e.g. mountain ecosystems, forests,agricultural areas, freshwater ecosystems, marine ecosystems and urban areas. The ecosystem services (ES) are based on the three main well-known categories (providing, regulating and cultural services). The provisional services in Norway include some very important ES like fish & seafood production, timber and pulp products, bioenergy and genetic resources, while the regulating services in Norway include important services like flood and landslide protection, pest and disease control in forestry and farming, carbon fixation in forests and air quality regulation. These services are also influenced by climate, pollution, urbanization and invasive species. Finally, the cultural services, like recreation & ecotourism, health and well-being, knowledge & learning and spiritual enrichment, are included. The values of the ES are estimated and quantified by direct (market based) and indirect methods (e.g. preferences).
The relative importance of these ES is estimated by questionnaires and cost/benefit analysis, and administrative measures are suggested to compensate for threats and lack of sustainability. However, non-renewable resources like oil, gas and minerals are not included in the present overview. Among the ES in mountains, the value of outdoor activity as estimated from preference studies is totally dominating over the value of hunting and reindeer husbandry. Among the ES in forests the highest values are related to the health benefit from recreation, followed by the value of carbon fixation. The willingness to protect certain forests with high biodiversity is also high. Among ES from agricultural areas the provisional services (food and food processing) are dominating, while in freshwater ecosystems the value of wild salmon fishing measured by payment willingness, is dominating over the willingness to pay for improved water quality. Finally, the most important ES in Norway in monetary terms are found in marine ecosystems. Among the urban ES, the value of outdoor recreation and improved air quality represent the highest values. The most frequent conflicts in Norway are probably those dealing with energy production (windmills, hydropower production, oil drilling) and sea farming vs. biodiversity and recreation, between mass tourism and nature conservation and between sheep farming and conservation of big predators like wolf, bear, lynx and wolverine.
Surgical Outcome of Intermittent Exotropia With Improvement in Control Grade Subsequent to Part-time Preoperative Occlusion Therapy
Authors: Bang Seung Pil , Lee Dong Cheol , Lee Se Youp 
Published: October 2017

Purpose:
To evaluate the effect of improvement in the control grade of intermittent exotropia using part-time occlusion therapy on the final postoperative outcome.

Methods:
Control of intermittent exotropia was graded as good, fair, or poor in 89 consecutive patients with intermittent exotropia during their first visit. The patients were reevaluated after part-time preoperative occlusion therapy and divided into two groups (improvement and no improvement) according to whether they showed improvement in control grade. The surgical success rate was compared retrospectively between the two groups.

Results:

The mean angle of deviation on the first visit was 27.61 ± 5.40 prism diopters (PD) at distance and 29.82 ± 5.28 PD at near. There were significant improvements in the angles of deviation for distance (26.17 ± 5.09 PD) and near (27.26 ± 5.56 PD) after part-time occlusion (both
P
< .001). The 49 patients who had a significantly improved control grade had a significantly better surgical success rate (77.6%) than the 40 patients who did not (50%;
P
= .007).

Conclusions:
Part-time occlusion therapy improves the control grade of intermittent exotropia, leading to a better likelihood of successful surgery and a reduction of the angles of deviation for distance and near.

[
J Pediatr Ophthalmol Strabismus
. 2018;55(1):59–64.]