bluuebunny/crossref_metadata_2025 huggingface dataset:
Revised Stellar Properties of Kepler Targets for the Q1-17 (DR25) Transit Detection Run
Authors: Mathur Savita , Huber Daniel , Batalha Natalie M. , Ciardi David R. , Bastien Fabienne A. , Bieryla Allyson , Buchhave Lars A. , Cochran William D. , Endl Michael , Esquerdo Gilbert A. , Furlan Elise , Howard Andrew , Howell Steve B. , Isaacson Howard , Latham David W. , MacQueen Phillip J. , Silva David R.
Published: March 2017

The determination of exoplanet properties and occurrence rates using Kepler data critically depends on our knowledge of the fundamental properties (such as temperature, radius, and mass) of the observed stars. We present revised stellar properties for 197,096 Kepler targets observed between Quarters 1–17 (Q1-17), which were used for the final transiting planet search run by the Kepler Mission (Data Release 25, DR25). Similar to the Q1–16 catalog by Huber et al., the classifications are based on conditioning published atmospheric parameters on a grid of Dartmouth isochrones, with significant improvements in the adopted method and over 29,000 new sources for temperatures, surface gravities, or metallicities. In addition to fundamental stellar properties, the new catalog also includes distances and extinctions, and we provide posterior samples for each stellar parameter of each star. Typical uncertainties are ∼27% in radius, ∼17% in mass, and ∼51% in density, which is somewhat smaller than previous catalogs because of the larger number of improved

constraints and the inclusion of isochrone weighting when deriving stellar posterior distributions. On average, the catalog includes a significantly larger number of evolved solar-type stars, with an increase of 43.5% in the number of subgiants. We discuss the overall changes of radii and masses of Kepler targets as a function of spectral type, with a particular focus on exoplanet host stars.
The InterPlanetary Network Supplement to the Second Fermi GBM Catalog of Cosmic Gamma-Ray Bursts
Authors: Hurley K. , Aptekar R. L. , Golenetskii S. V. , Frederiks D. D. , Svinkin D. S. , Pal’shin V. D. , Briggs M. S. , Meegan C. , Connaughton V. , Goldsten J. , Boynton W. , Fellows C. , Harshman K. , Mitrofanov I. G. , Golovin D. V. , Kozyrev A. S. , Litvak M. L. , Sanin A. B. , Rau A. , Kienlin A. von , Zhang X. , Yamaoka K. , Fukazawa Y. , Ohno M. , Tashiro M. , Terada Y. , Barthelmy S. , Cline T. , Gehrels N. , Cummings J. , Krimm H. A. , Smith D. M. , Monte E. Del , Feroci M. , Marisaldi M.
Published: March 2017

InterPlanetary Network (IPN) data are presented for the gamma-ray bursts in the second Fermi Gamma-Ray Burst Monitor (GBM) catalog. Of the 462 bursts in that catalog between 2010 July 12 and 2012 July 11, 428, or 93%, were observed by at least 1 other instrument in the 9-spacecraft IPN. Of the 428, the localizations of 165 could be improved by triangulation. For these bursts, triangulation gives one or more annuli whose half-widths vary between about 2.′3° and 16°, depending on the peak flux, fluence, time history, arrival direction, and the distance between the spacecraft. We compare the IPN localizations with the GBM 1σ, 2σ, and 3σ error contours and find good agreement between them. The IPN 3σ error boxes have areas between about 8 square arcminutes and 380 square degrees, and are an average of 2500 times smaller than the corresponding GBM 3σ localizations. We identify four bursts in the IPN/GBM sample whose origins were given as “uncertain,” but may in fact be cosmic. This leads to an estimate of over 99% completeness for the GBM catalog.
A Comparison of Grid-based and SPH Binary Mass-transfer and Merger Simulations
Authors: Motl Patrick M. , Frank Juhan , Staff Jan , Clayton Geoffrey C. , Fryer Christopher L. , Even Wesley , Diehl Steven , Tohline Joel E.
Published: March 2017

There is currently a great amount of interest in the outcomes and astrophysical implications of mergers of double degenerate binaries. In a commonly adopted approximation, the components of such binaries are represented by polytropes with an index of n = 3/2. We present detailed comparisons of stellar mass-transfer and merger simulations of polytropic binaries that have been carried out using two very different numerical algorithms—a finite-volume “grid” code and a smoothed-particle hydrodynamics (SPH) code. We find that there is agreement in both the ultimate outcomes of the evolutions and the intermediate stages if the initial conditions for each code are chosen to match as closely as possible. We find that even with closely matching initial setups, the time it takes to reach a concordant evolution differs between the two codes because the initial depth of contact cannot be matched exactly. There is a general tendency for SPH to yield higher mass transfer rates and faster evolution to the final outcome. We also present comparisons of simulations calculated from two different energy equations: in one series, we assume a polytropic equation of state and in the other series an ideal gas equation of state. In the latter series of simulations, an atmosphere forms around the accretor, which can exchange angular momentum and cause a more rapid loss of orbital angular momentum. In the simulations presented here, the effect of the ideal equation of state is to de-stabilize the binary in both SPH and grid simulations, but the effect is more pronounced in the grid code.
Variation of Ionizing Continuum: The Main Driver of Broad Absorption Line Variability
Authors: He Zhicheng , Wang Tinggui , Zhou Hongyan , Bian Weihao , Liu Guilin , Yang Chenwei , Dou Liming , Sun Luming
Published: March 2017

We present a statistical analysis of the variability of broad absorption lines (BALs) in quasars using the large multi-epoch spectroscopic data set of the Sloan Digital Sky Survey Data Release 12 (SDSS DR12). We divide the sample into two groups according to the pattern of the variation of C iv BAL with respect to that of a continuum: the equivalent widths (EW) of the BAL decreases (increases) when the continuum brightens (dims) as group T1; and the variation of the EW and the continuum in the opposite relation of group T2. We find that T2 has significantly (

, Students T Test) higher EW ratios (R) of Si iv to C iv BAL than T1. Our result agrees with the prediction of photoionization models that

column density increases (decreases) if there is a (or no)

ionization front, while R decreases with the incident continuum. We show that BAL variabilities in at least 80% of quasars are driven by the variation of an ionizing continuum, while other models that predict uncorrelated BAL and continuum variability contribute less than 20%. Considering large uncertainty in the continuum flux calibration, the latter fraction may be much smaller. When the sample is binned into different time intervals between the two observations, we find significant difference in the distribution of R between T1 and T2 in all time-bins down to

days, suggesting that the BAL outflow in a fraction of quasars has a recombination timescale of only a few days.
Spectroscopy of Ultra-diffuse Galaxies in the Coma Cluster
Authors: Kadowaki Jennifer , Zaritsky Dennis , Donnerstein R. L.
Published: March 2017

We present spectra of five ultra-diffuse galaxies (UDGs) in the vicinity of the Coma cluster obtained with the Multi-object Double Spectrograph on the Large Binocular Telescope. We confirm four of these as members of the cluster, quintupling the number of spectroscopically confirmed systems. Like the previously confirmed large (projected half-light radius >4.6 kpc) UDG, DF44, the systems we targeted all have projected half-light radii

. As such, we spectroscopically confirm a population of physically large UDGs in the Coma cluster. The remaining UDG is located in the field, about 45 Mpc behind the cluster. We observe Balmer and Ca ii H and K absorption lines in all of our UDG spectra. By comparing the stacked UDG spectrum against stellar population synthesis models, we conclude that, on average, these UDGs are composed of metal-poor stars ([Fe/H] ≲ −1.5). We also discover the first UDG with [O ii] and [O iii] emission lines within a clustered environment, demonstrating that not all cluster UDGs are devoid of gas and sources of ionizing radiation.
On the Absence of Non-thermal X-Ray Emission around Runaway O Stars
Authors: Toalá 杜 J. A. 宇君 , Oskinova L. M. , Ignace R.
Published: March 2017

Theoretical models predict that the compressed interstellar medium around runaway O stars can produce high-energy non-thermal diffuse emission, in particular, non-thermal X-ray and γ-ray emission. So far, detection of non-thermal X-ray emission was claimed for only one runaway star, AE Aur. We present a search for non-thermal diffuse X-ray emission from bow shocks using archived XMM-Newton observations for a clean sample of six well-determined runaway O stars. We find that none of these objects present diffuse X-ray emission associated with their bow shocks, similarly to previous X-ray studies toward ζ Oph and BD+43°3654. We carefully investigated multi-wavelength observations of AE Aur and could not confirm previous findings of non-thermal X-rays. We conclude that so far there is no clear evidence of non-thermal extended emission in bow shocks around runaway O stars.
Dusty Winds in Active Galactic Nuclei: Reconciling Observations with Models
Authors: Hönig Sebastian F. , Kishimoto Makoto
Published: March 2017

This Letter presents a revised radiative transfer model for the infrared (IR) emission of active galactic nuclei (AGNs). While current models assume that the IR is emitted from a dusty torus in the equatorial plane of the AGNs, spatially resolved observations indicate that the majority of the IR emission from ≲100 pc in many AGNs originates from the polar region, contradicting classical torus models. The new model CAT3D-WIND builds upon the suggestion that the dusty gas around the AGNs consists of an inflowing disk and an outflowing wind. Here, it is demonstrated that (1) such disk+wind models cover overall a similar parameter range of observed spectral features in the IR as classical clumpy torus models, e.g., the silicate feature strengths and mid-IR spectral slopes, (2) they reproduce the 3–5 μm bump observed in many type 1 AGNs unlike torus models, and (3) they are able to explain polar emission features seen in IR interferometry, even for type 1 AGNs at relatively low inclination, as demonstrated for NGC3783. These characteristics make it possible to reconcile radiative transfer models with observations and provide further evidence of a two-component parsec-scale dusty medium around AGNs: the disk gives rise to the 3–5 μm near-IR component, while the wind produces the mid-IR emission. The model SEDs will be made available for download.
El comercio de estampas entre Roma y España a finales del siglo XVI: el caso del mercader italiano Antonio Pisano
Authors: Tarifa Castilla María Josefa
Published: March 2017

El presente estudio revela la llegada al norte de España de estampas y libros adquiridos en Roma en el viaje realizado entre 1582 y 1583 por el italiano Antonio Pisano, financiado gracias a la compañía mercantil temporal establecida entre éste y el genovés Juan Luis de Musante, maestro mayor de obras reales de Felipe II en Navarra, residentes en Pamplona. Grabados de temática sacra y profana realizados por destacados artistas de la época, como el holandés Cornelis Cort y los mantuanos Adamo y Diana Ghisi, además de libros de figuras, algunos de artistas tan sobresalientes como Michelangelo o Polidoro da Caravaggio.
Preparing Engineering Students for the Global Sourcing Environment
Authors: Manzione Louis , Abuaisheh Akram , Sumukadas Narendar , Congden Steve
Published: March 2017

Abstract—Globalization and rapid changes in modern product development and realization are creating gaps in engineering education systems around the world. The global economy has changed the way that engineering firms design, develop, and produce their products. Companies need to evaluate many options available worldwide, not just locally. The current trends are only likely to continue as the world economy becomes more competitive, interdependent, and characterized by global relationships among supply chain partners.  This paper presents a plan for preparing engineering students for the new global sourcing environments and product realization processes. Infusions of supply chain management and project management skills into the curriculum are recommended, as well as use of university-industry partnerships, course portfolios, and study abroad programs.
Les ironies de (la) serendipity dans l’œuvre de Robert K. Merton
Authors: Saint-Martin Arnaud
Published: March 2017

Dans quelles circonstances et pourquoi Robert K. Merton a-t-il rencontré l’idée de serendipity ? Quelle place occupe-t-elle dans son œuvre ? Cet article propose de reconstituer pas à pas l’histoire de cette rencontre, qui ne manque pas d’ironie ni de piquant. En elle-même « sérendipienne », la découverte accidentelle mais tellement féconde du mot serendipity ouvrit à Merton nombre de pistes de recherche au cours des années 1940. Le concept intrigant de la découverte fortuite qui – entre autres vertus – engendre des résultats de nature à transformer la théorie promettait d’enrichir et de renouveler la connaissance objective. Mais la serendipity était plus qu’une recette heuristique à appliquer en science. Chez Merton, c’était aussi l’objet privilégié et « auto-exemplifiant » d’une sémantique sociologique des concepts, dont l’ambition est d’étudier les itinéraires des terminologies dans la culture. En retraçant la genèse de la recherche qu’il mena avec Elinor Barber sur l’histoire du mot et des significations parfois volatiles de la serendipity (recherche plus ou moins terminée en 1958, mais publiée seulement en 2002), on parviendra à saisir pourquoi ce thème revêtait pour Merton un double intérêt stratégique, à la fois épistémologique et autobiographique. On comprendra aussi pourquoi une nouvelle traduction en français du premier fragment d’article dans lequel le sociologue conceptualise la serendipity en 1948 est de bonne méthode sérendipienne.
The Study of Nonmetallic Inclusions Formation for Kaplan Blades during the Solidification Process
Authors: Lupinca Cinca Ionel , Marta Constantin , Fanica Cristian , Budai Ana Maria
Published: March 2017

The exploitation durability of Kaplan hydraulic turbines blades is first of all determined by their structure, by the steel elaboration technology, respectively by the content of non-metallic inclusions and later by the physical-chemical parameters of the exploitation environment.This paper presents a study regarding the situations in which the elaboration-casting technology of Kaplan blades using alloyed austenitic stainless steel, X5CrNiMo17-13-3 which has an important role in the quality of castings. Thus, the authors verify the formation of sulfides and of oxi-sufides during the steel elaboration process, treatment during a liquid state and their influence in the castings behavior to wearing. It is a well known fact that the presence of sulfides and oxi-sufides in the cast blades structure accelerates the corrosion process in contact with river waters.
Precipitation in Cu-Bearing GOES at the Start of Primary Recrystallization
Authors: Volodarskaja Anastasia , Holešinský Jan , Miklušova Šárka , Vodárek Vlastimil
Published: March 2017

The role of copper additions to GOES has not been fully understood yet. Several mechanisms have been proposed: stabilization of austenite during hot rolling in two phase α+γ region, precipitation of ε - Cu, dissolution and re-precipitation of Cu-bearing sulfides, segregation of copper at grain boundaries and support of deformation by twinning and shear during cold rolling.This paper deals with minor phase evaluation in Cu–bearing GOES after following manufacturing steps: a) the first cold rolling and decarburization annealing at 820 °C, b) the second cold rolling followed by a slow laboratory heating to the temperature of primary recrystallization (620°C). Microstructure analysis was carried out using EBSD and TEM techniques. Results of experimental studies were compared with Thermocalc predictions of the copper effect on equilibrium phases in GOES.
Changes of Microstructure and Grainsize of Martensitic Stainless Steel during the Processes of Hot Reversed Extrusion, Broaching and Heat Treating
Authors: Kučera Pavel , Mazancová Eva
Published: March 2017

The field of high pressure steel cylinders (HPSC) used for the variety of applications, such as storage of technical gases, compressed natural gas (CNG), medical gases and special applications like scuba diving cylinders is still significantly expanding. With increasing safety requirements, the need of new techniques applied in field of HPSC structural and materials innovations comes into place.Speaking mainly about the field of scuba diving cylinders, the need of corrosion protection of inner surface comes in place due to the possible risk of valve blockage by metal corroded particles of inner surface. Even such a risk occurs in extremely rare occasions, there was until now no generally applied solution (such as inner wet, powder or Teflon coating, etc.) due to significantly high costs of such additional inner surface protection. Another problem that occurs so far are significant visual imperfections of scuba diving cylinders caused by the rough treating by scuba divers during the use and manipulation that causes chipping of outer surface painting and subsequent corroded areas.The breakthrough solution is the scuba diving cylinder made of a stainless steel by the processes of reversed extrusion and broaching from billet without any need of an additional coating. No such a product was made so far by these methods of production and no evidence of an evolution of the microstructure and grainsize changes during such manufacturing with subsequent heat treating was ever documented and analysed.
Microstructure and Mechanical Properties of 9CrNB Steel after Heat Treatment
Authors: Bekeč Pavel , Parilák Ľudovít , Beraxa Pavol , Mojžiš Milan , Domovcová Lucia , Fujda Martin
Published: March 2017

This paper deals with the analysis of microstructure in the conditions after austenitising at high temperatures (1150 °C, 1180 °C a 1210 °C/45 min) for 9CrNB steel, and with the analysis of microstructure in the conditions after subsequent tempering at temperatures 740 °C, 770 °C, 800 °C/1 hr. After austenitising the microstructure was formed of lath martensite with secondary carbides. The average size of initial austenitic grains ranged from 144 μm (1150 °C) to 163 μm (1210 °C). Increasing the austenitising temperature led to insignificant improvement in strength properties, while the plasticity of the steel decreased. Microstructure in tempered conditions was formed from tempered martensite. This martensite had lath morphology, with inhomogeneus distribution of precipitates. Higher austenitising temperature and increased tempering temperature led to spheroidal and growth of secondary particles. The tempering effect on strength and plastic properties of steel are also described.
Deformation and Failure of Ultrafine-Grained Cu at Subambient Temperature
Authors: Juríková Alena , Csach Kornel , Miškuf Jozef , Hurakova Maria , Tabachnikova Elena D. , Podolskiy Aleksey V.
Published: March 2017

The ultrafine-grained copper was obtained by 12 passes of equal-channel angular pressing method. The uniaxial tensile tests at room temperature and the subambient temperature of 77 K show that the yield stress increases from the value of 128 MPa to the value of 138 MPa, respectively. In addition, the lowering the test temperature tends to the increase of the deformation before the failure. The fractographic analysis shows the transcrystalline ductile failure for all samples. Due to the high plasticity of nanostructured copper no influence of the nanoporosity on the failure process was observed.
Fracture Properties of Mg-Alloys Assessed with Nanoindentation
Authors: Němeček Jiří , Hrbek Vladimír , Petráňová Veronika , Hlaváček Petr
Published: March 2017

This paper deals with micromechanical properties of biocompatible magnesium alloys MgCa0.8 prepared by extrusion. At first, the microstructure, elastic and hardness properties are assessed at the scale of one micrometer by means of a nanoindenter. Further, determination of fracture mechanism, fracture area and fracture toughness of the alloy is studied with sharp indentation, optical microscopy and SEM and by means of energetic methods. Based on the examination of optical images it was concluded that the Mg matrix is not vulnerable to distinct cracking around indents even for high indentation loads. By computations, it was found the fracture area is very small, about 0.7-3% of the tip contact area based on the assumption of limit values of the target fracture toughness 10-20 MPa·m1/2.
Investigation of Failed Wheel Rim Weld Joints
Authors: Drotár Atila , Duška Jaroslav , Hrabčáková Lucia , Kalmár Peter , Mašlejová Alicia
Published: March 2017

Material used for car sheet wheels production was analyzed due to limited weldability. During the manufacturing of wheel rims, during shaping - cold forming cracks were initiated in the weld joint and in its heat affected zone. The destruction of rims occurred during their shaping. The wheel rims were welded at their manufacturer's site applying the compression technology and using the direct current welding source. Five rims were supplied for the metallographic analysis of which two were with conforming weld joint, and in the case of three rims there was a rupture at the weld joint point; on one them along the whole width of the rim. The rupture of the rim weld joint across its whole width at the weld joint point that was made by diffusionless connection was caused by a low welding input power. The primary cause of the rim cracking initiation on the transverse weld joint was the presence of micro-cracks, micro-notches in the vicinity of the weld joint and the heat affected zone, the notch effect of which was manifested during the rim forming. The occurrence of micro-notches was shown in the heat affected zone as well as on the conforming weld joint of one rim. The carbon equivalent Ce from the measured values of the material chemical composition of all rims was in the range from 0.175 to 0.201. Given the declared weldability guaranteed up to the value of Ce = 0.45, all analyzed materials complied with the requirement. Material cleanliness, grain size and linearity met the requirements of specification for material MW 01. Given the insufficient quality of the material was not the primary cause of the defect, it was recommended to eliminate the occurrence of potential notches in the heat affected zone through slightly planning of the weld collar.
Methodology for In Situ Microstructural Characterisation of AZ31 Magnesium Alloy Corrosion Degradation in Hanks' Solution
Authors: Doležal Pavel , Fojt Lukáš , Minda Jozef
Published: March 2017

Due to their specific properties magnesium and magnesium alloys find huge application possibilities mainly in automotive, engineering, transport and space industry. Important properties of magnesium alloys for engineering applications are high specific strength and high internal dumping values, while biocompatibility, biotoxicity and biodegradability open them the possibility to be used for biomedical applications. Development of new biodegradable magnesium alloys, investigation of new production and processing technologies on their properties and evaluation of corrosion degradation in simulated body fluids solutions are the main topics of the last decades.The paper offers a method simulating in-vivo tests for description of the corrosion process of potential biomedical materials in time using atomic force microscopy (AFM). To prove the proposed methodology detailed analysis of the corrosion degradation of AZ31 cast magnesium alloy in flowing Hanks’ balanced salt solution (HBSS) was performed. Corrosion degradation process of the examined alloy was influenced by different microstructural features and their interfaces. Results of the created corrosion galvanic cells and the corrosion attack evolution on the interface of the present intermetallic phases and the matrix led to profile changes detected by AFM.
Open Questions in Nanosegregation
Authors: Lejček Pavel
Published: March 2017

Despite nanosegregation of solutes at grain boundaries has been intensively studied in the past decades and numerous theoretical data as well as experimental values on characteristic energies and/or enthalpies and entropies exist some questions remain still unanswered. In this paper some of these questions – Which energetic quantities obtained in different ways, experimentally and theoretically, can be mutually compared What is the segregation site of a solute in the grain boundary core – are discussed in more detail. It will be shown that the entropy of grain boundary segregation plays an important and indisputable role in responding some issues and that understanding of its role will help us to elucidate fundamentals of the grain boundary segregation.
Metallographic Characterization and Fatigue Damage Initiation in Ti6Al4V Alloy Produced by Direct Metal Laser Sintering
Authors: Konečná Radomila , Nicoletto Gianni , Bača Adrián , Kunz Ludvík
Published: March 2017

Direct Metal Laser Sintering (DMLS) is a complex process where a part is build-up by localized melting of gas atomized powder layers by a concentrated laser beam followed rapid solidification. The microstructure of DMLS produced material is substantially different from that of conventionally manufactured materials, although the ultimate strength is similar. However, yield strength and elongation and especially fatigue behavior may vary considerably according to the process parameters and post fabrication heat treatment because they affect structural heterogeneity, porosity content, residual stresses, and surface conditions. Fatigue tests of DMLS Ti6Al4V alloy are interpreted in the light of a thorough metallographic and fractographic investigation. The fatigue crack initiation for three different cyclic stress directions with respect to build direction is determined by fractography.
Microstructure of the NiMnGa Heusler Alloys Prepared by Suction Casting and Melt-Spinning
Authors: Diko Pavel , Kavečanský Viktor , Piovarči Samuel , Ryba Tomáš , Vargova Zuzana , Varga Rastislav
Published: March 2017

The microstructure of the Ni50Mn25Ga25 Heusler alloy (HA) rod cast to a copper mould and melt-spun ribbon was studied. According to X-ray diffraction analyses in both cases, the solidified alloy is a single-phase. In suction casting, the radial columnar crystals grow by cellular or dendritic growth, which leads to chemical inhomogeneity of the whole cast rod on the microscopic scale. The melt-spun ribbon exhibits a homogeneous alloy at the wheel side and an inhomogeneous alloy on the free surface side of the ribbon formed by cellular and dendritic growth. At both types of casting, the columnar crystals growth along the <100> crystal direction. According to texture analyses by EBSD, the fine grain structure at the wheel side of the ribbon exhibits no texture, while the columnar grain structure on the free surface side exhibits the <100> fibre texture with a declination by about 10 degrees in the spinning direction. Melt-spinning leads to significant refinement of the HA microstructure.
Effect of Structure and Cyclic Loading on the Internal Damping Capacity
Authors: Dresslerová Zuzana , Palček Peter , Chalupová Mária
Published: March 2017

The damping capacity, which was characterized by dissipating of mechanical energy, was examined in magnesium alloys (AZ31, AZ61 and AZ91). Internal damping is usually divided into three regions, namely the regions in which the internal damping is strain independent, weakly dependent and strongly dependent. The article is focused on the critical amplitudes of deformation which separate the strain independent, weakly dependent and strongly dependent regions. In experimental measurements resonance method was used, which is based on continuous excitation of oscillations of the specimen and the entire apparatus vibrates at a frequency which is near to the resonance.
Effect of Long-Term Aging on Microstructural Restoration in Cast Nickel Base Superalloy, GTD-111
Authors: Paa-Rai Chuleeporn , Norachan J. , Wangyao Panyawat , Polsilapa Sureerat , Lothongkum Gobboon
Published: March 2017

In this research study, the effect of long-term aging after various solutioning temperatures on final microstructure was investigated. The cast nickel base superalloy, GTD-111, usually has standard reheat treatment as follows: solutioning treatment at 1448 - 1478 K for 7.2 ‑ 21.6 ks and aging at 1118 K for 86.4 ks. However, from previous research works, the density of γ՛ phase was not reached the optimum value. Therefore, extension of aging time was performed in the study from 90 to 180, 270, 360, 720, 1080 and 1440 ks in order to increase density or volume fraction of precipitating γ՛ particles. From the results, it was found that longer aging time provided higher values of both area fraction and size of γ՛ particles. However, increase in aging time resulted in the hardness decrease.
Effect of Alloying Elements on the Reactive Sintering Behaviour of NiTi Alloy
Authors: Novák Pavel , Salvetr Pavel , Školáková Andrea , Karlík Miroslav , Kopeček Jaromír
Published: March 2017

NiTi alloy is usually prepared by casting and forming. As an innovative process, reactive sintering powder metallurgy is tested worldwide, aiming to prepare pure NiTi alloy easily from nickel and titanium powders. This process enables to prepare both porous and low-porosity alloy, depnding on the process conditions. However, the formation of NiTi phase in this process is always accompanied by the Ti2Ni phase, which is hard, brittle, less corrosion resistant and does not have the shape memory. In this work, various alloying elements (Al, Si, Mg, Fe, Nb, V) were added to Ni-Ti alloy in order to lower the amount of Ti2Ni phase or at least to minimize its undesirable effect on the alloy properties. The reactive sintering behaviour, phase composition and mechanical properties of Ni-Ti-X alloys were described.
Microstructure and Erosion Resistance of Zirconium Diboride Ceramics Infiltrated by Pure Copper
Authors: Beronská Naďa , Štefánik Pavol , Kavecký Štefan , Opálek Andrej , Kollarovičová Andrea , Nagy Štefan , Iždinský Karol
Published: March 2017

Cu/ZrB2 composite was prepared by gas pressure infiltration of molten metal into ceramic preform. Microstructure and erosion resistance of composite was investigated. The microstructure was analysed by light microscopy and scanning electron microscopy. The chemical compositions were analysed using energy dispersive X-ray spectroscopy. Good penetration of copper along the grain boundaries of the 60% porosity sintered ceramics was analysed in the whole volume of composite. The interfacial morphology shows the regular interfaces without any macroscopic reactions [1]. Cu/ZrB2 composite was subjected to 60 spark discharges to investigate the ablation resistance. Linear dependence of the amount of loss material on the number of electrical discharge analytical cycles for Cu/ZrB2 composite was determined.
Detecting Water in Composite Sandwich Panels by Using Infrared Thermography
Authors: Čapka Alexander , Vavilov Vladimir , Rusnáková Soňa , Fojtl Ladislav , Žaludek Milan , Maňas Lukáš
Published: March 2017

Honeycomb composite structures widely used in aviation are sturdy and light-weight but they may accumulate water from the atmosphere during aircraft operation. The presence of water in honeycomb cells leads to a higher airplane mass and excessive corrosion of aluminum cores, while the frozen water endangers panel integrity. This work describes the use of infrared thermography for detecting water trapped in aviation honeycomb cells.
Enhancement of Magnetic Properties of 41CrMo4 Steel by Means of Diffusion Coatings
Authors: Jech David , Čelko Ladislav , Huzlík Rostislav , Bulín Tomáš , Klakurková Lenka , Švejcar Jiří , Kaiser Jozef
Published: March 2017

The knowledge of magnetic and transport properties of construction steels for magnetic circuits plays an important role. Three different techniques: (i) flame spray, (ii) twin wire arc spray and (iii) powder mixture with halide activator were used to produce Si, CuSn6 and Si coatings, respectively, on the 41CrMo4 steel ring substrates. Immediately after the thermal spraying or inserting the steels into the powder mixture was used isothermal heat treatment at the temperatures of 800 °C / 6 hrs, 1000 °C / 4 hrs and 1250 °C / 2 hrs to produce the diffusion coatings. Several coating systems consisting of different phases and thicknesses were manufactured. Opto-digital microscope, scanning electron microscope and digital image analysis, second equipped with energy dispersive microanalyzer, were utilized to characterize the microstructure, chemical composition and thicknesses of the coatings. The influence of coatings on magnetic properties in the frequency range of 50-2000 Hz was also measured.
Steel Pile-Up Characterization by Atomic Force Microscopy
Authors: Burik Peter , Zubko Pavol , Pešek Ladislav , Voleský Lukáš
Published: March 2017

The Oliver–Pharr method has extensively been adopted for measuring hardness and Young’s modulus by indentation techniques. However, the method assumes that the contact periphery sinks in, which limits the applicability to the materials pile-up [1]. In this work, we characterize the pile-up (shape and height) in steel sheets with different mechanical properties and propose an improved methodology to calculate the real mechanical characteristics of steel sheets with significant pile-up. Pile-up correction of mechanical characteristics is based on ratio of pile-up height and contact depth. Pile-up height was measured by atomic force microscopy (AFM).
The Effect of Applied Load on Hardness of Steels
Authors: Mareš Vratislav , Kraus Martin , Podeprelova Adéla
Published: March 2017

Hardness measurements can simple, but very useful provide materials mechanical properties. This is atest that is extremely localized in volume and does not affect significantly the structural properties. Theaim of this article is to highlight on influence of the applied load forces to the hardness measurementresults. In engineering practice it is generally the most widely used method of measuring the Vickershardness. This method has a variability of the loading forces in a wide range from nano/micro up tohigh loads in hundreds N. There is a well-known plastic material response, therefore, were taken intoaccount several steels commonly used in technical practice S355 NL+N, 316LVM, 34CrMo-4. Wheninterpreting the results should always point out to the value of the load. In common engineering practiceleads to confusion, or to comparing the hardness of the material obtained at different loads. Thisproblem is quite often occurs at nowadays and needs to be solved. Focus should be not only in termsof results depending on the load, but also from a statistical perspective of scattering measurements atvarious loads. Generally, in the technical practice is discussed independence measurement results ofVickers hardness on applied load, due geometric similarity of indents. When is used different forcesthere is a changed of the hardness results. This phenomenon is known as a size effect. This effect isgenerally related to each mechanical testing of materials. However, engineering practice getting intoconflict with this effect.
A Possible Correlation Investigation between Young's Modulus and Thermal Properties of Green Composites
Authors: Chikhi Mourad , Agoudjil Boudjemaa , Mokhtari Fatiha
Published: March 2017

In this article greencomposites based on gypsum reinforced with date palm fibers (DPF) were fabricated and investigated experimentally in terms of thermal and mechanical properties. This paper deals with two aspects, the first one is a study on the influence of fibers sizes and content on thermal diffusivity and Young’s modulus of date palm fibers (DPF) reinforced gypsum composite. The second one is an experimental correlation investigation between Young’s modulus and thermal properties (thermal conductivity, thermal diffusivity). According to the results of this study, the Young’s modulus and the thermal diffusivity of the greencomposites is mainly influenced by the interfacial adhesion between the matrix and fibers. The experimental correlation between Young’s modulus and thermal properties shows variant results.
A New Approach of Shear Connectors to Delay Debonding of CFRP Laminates Used for Shear Strengthening of RС Beams
Authors: Jabbar Ali Sami Abdul , Alam Md. Ashraful , Mustapha Kamal Nasharuddin
Published: March 2017

Shear strengthening of RC beam with adhesively bonded carbon fiber reinforced-polymer (CFRP) laminates is becoming both environmentally and economically more preferable than replacement. However, the early separation of these plated stripes was the most critical failure which leads to prevent reaching the full capacity required from the strengthening. This study aims to present a new method to prevent debonding failure of CFRP laminates adhesively glued to concrete surface using embedded connectors to enhance the interfacial bond strength. Therefore, steel bar and adhesive connectors were fabricated and used at the interface of the bonded CFRP laminates. Five beam specimens including one control beam were tested to investigate the effects of the connectors to prevent or delay the premature debonding of the EB CFRP laminates. The experimental results showed that both steel and adhesive connectors completely prevented premature debonding failure of CFRP shear strip and allowed the beams to fail by flexure with full ductility and strength. Steel and adhesive connectors would enhance 33% and 38% failure loads respectively as compared to strengthened beam without connectors.
Modeling of Interface Heat Flux and Thermal Field of Mold Materials during Gravity Die Casting
Authors: Sreenivas Rao K.V. , Usha P. , Sanman S. , Anilchoudary R.
Published: March 2017

One of the key controllable and influential factors to obtain a casting simulation, representative of reality, is the choice of boundary condition. The thermal boundary condition to be specified at the metal-mold interface must account for complex heat transfer phenomena associated with solidifying casting. The present study aims at estimating the heat flux at the interface of the mold and the solidifying metal by Inverse Heat Conduction Problem (IHCP) approach. Solidification studies were conducted on casting of aluminum reinforced with boron carbide composite. Copper, cast iron and stainless steel were used as mold materials. The temperature data of the mold was recorded from the beginning to end of solidification using k-type thermocouples connected to temperature data logger. This time-temperature history was used as input to the IHCP algorithm to simulate the interface heat flux and thermal field of the mold. The results indicate that the interface heat flux is highly transient and varies with the variation in the thermo-physical properties of the mold materials. The study also demonstrates that heat conduction is one dimensional in copper mold and two dimensional in cast iron and stainless steel mold during phase change.
Study of Plasma Spraying Radar Absorbing Coating
Authors: Li Shu Qing , Li Qi Lian , Zhou Hai Bin , He Jin Sheng
Published: March 2017

By considering the problems occurred in the painted radar absorbing coating such as thickness is difficult to control, large densities, poor diffusion of coatings’ microstructure, lower bonding strength and easy to spall off the substrate, etc, in this study, the plasma spraying technology would be the coating fabricated method, the absorbing materials are designed to appropriate to plasma spray method, and the more uniform absorbing coating are fabricated by the auto-mechanical controlling. At the same time, the coatings’ bonding strength with the substrate and the coatings’ absorbing property are researched by the different design of the coatings’ thickness. Test results indicated that thermal spraying absorbing coating has certain absorbing ability, however, it is lower than the painted coating. Otherwise, the plasma spraying coating has more uniform microstructure, more higher bonding strength, and the coating has more lighter weight, these above characters just pointed out the goal of the absorbing coatings.
An Experimental Study for Low-Cycle Fatigue Crack Propagation of Glidcop Al-15
Authors: Yin Yan , Chen Hai Bo , Xiao Wei Ling
Published: March 2017

Experiments have been conducted on an oxide dispersion strengthened (ODS) copper Glidcop Al-15 under a range of cyclic stress-amplitudes at room temperature. Special specimens containing an artificial small hole of various diameters, i.e. 150, 200 and 300 μm, were used. Propagation process of surface cracks in the various holed specimens was recorded to investigate the fatigue crack growth rate. Scanning electron microscope (SEM) was used for the observation of the fracture surface after failure specimens. The well-known Coffin-Manson low-cycle fatigue relationship was substantially shown through the results. An equation between the growth rate of the surface crack and the stress amplitude for Gidcop Al-15 was carried out. The experiment proved that prior fatigue history makes little influence on the subsequent crack propagation property under low-cycle condition.
The Properties of Iron Oxide Desulfurization Sorbents Regenerated under the Synergy of SO2-O2 Atmosphere
Authors: An Jia , Ju Shang Guan , Guan Hu Ai , Yu Jun Ming , Yang Lei , Mi Jie , Miao Mao Qian
Published: March 2017

Iron oxide (Fe2O3) desulfurization sorbent was prepared from FeSO4 and NH4HCO3 by precipitation method, and its regeneration behavior under different atmosphere was studied by using Thermos gravimetric analyzer. It is found that the regeneration of Fe2O3 desulfurization sorbent is the best in the synergy of SO2-O2 atmosphere. When the concentration of O2 or SO2 in the synergy of SO2-O2 atmosphere was increased, the regeneration time can be reduced, which is beneficial to the regeneration of iron oxide desulfurization sorbent. The regeneration of Fe2O3 desulfurization sorbent in the synergy of SO2-O2 atmosphere can not only prevent sorbent sintering in single O2 atmosphere but also improve the rate of regeneration in single SO2 atmosphere.
Au Nanoparticles Doped TiO2 Mesoporous Perovskite Solar Cells
Authors: Abdoul-Latif Mouna Mohamed , Xu Jia , Yao Jian Xi , Dai Song Yuan
Published: March 2017

The incorporation of metal nanoparticles is not a new method, but remains a method not enough investigated in perovskite solar cells. Many others studies about organometal halide perovskite have been done to improve thin film photovoltaic devices efficiencies. This enhancement has been due to materials purity, surface passivation or surface area adsorbent but the main enhancement has been either by fast electron extraction or light harvester which allowed increasing the Photocurrent Density (Jsc). In many literatures, we find that Plasmon effect can improve the absorption of solar cells. In this study we used a sol-gel method to incorporate metal nanoparticles into TiO2 in perovskite solar cells and we investigated the absorption, interface matters and efficiency with gold nanoparticles (Au NPs) doped TiO2 perovskite solar cells. We consider they are many parameters that may have an effect on light absorption in perovskite solar cells using Au NPs doped TiO2, but the most enhancements are done either by reducing exciton binding energy or by a better crystalline surface.
Influence of PCBM on the Glass Transition Temperature (Tg) of Poly(N-Vinylcarbazole)-Based Photorefractive Composite
Authors: Chen Bai Li , Huang Chuan Qun , Yang Rui Zhuang , Fang Yu , Zhang Qing Jun , Luo Xuan , Shao Ting , Chen Shu Fan
Published: March 2017

2,5-dimethyl-(4-p-nitrophenylazo) phenetole (DMNPAPE) was synthesized. And its structure was confirmed with ultraviolet-visible (UV-vis) spectroscopy, Fourier transform infrared (FT-IR) spectra and 1H Nuclear Magnetic Resonance (1H NMR) spectroscopy. The photorefractive composite consist of 33 wt % poly (N-vinycarbazole) (PVK), 50 wt % 2, 5-dimethyl-(4-p-nitrophenylazo) phenetole (DMNPAPE) and 16 wt % ethyl carbazole (ECZ) doped with x wt % (≤1 wt%) [6, 6]-phenyl C61 butyric acid methyl ester (PCBM) was fabricated. The influence of PCBM on the glass transition temperature (Tg) of the photorefractive composite was studied using a differential scanning calorimetric (DSC) method. The active energy of glass transition (Eg) was evaluated by Kissinger’s and Moynihan’s relation. The analysis results indicate that the transition region shifts to higher temperatures with the increasing heating rate, and PCBM content (≤1.0 wt %) can influence Tg of PVK - based PR composite polymers. The Tg first increase and then went down with the PCBM content (below 1.0 wt %) increasing. The possible cause of the influence of PCBM on Tg was proposed.
Effects of MoS2 on Tribological Properties and Mechanically Mixed Layer of Al Matrix Composites
Authors: Chen Bai Ming , Zhang Jun Xi , Liang Ze Fen , Yi Xiang Bin , Zhang Zheng Yu
Published: March 2017

Al matrix composites containing MoS2 at weight fractions in the range of 0%, 3%, 10%, were fabricated by hot press method, respectively. The effect of MoS2 on tribological properties and mechanically mixed layer of Al matrix composites were investigated on a pin-on-disc tester at load of 20~50N and sliding speed of 0.23~0.69m/s. Worn surfaces and mechanically mixed layer of composites were characterized by scanning electron microscopy(SEM). Results indicate that the hardness and compression strength of composite with 3% content of MoS2 has a little higher than that of composite with 0% content of MoS2, but the hardness and compression strength of composite with 10% content of MoS2 were dropped sharply. With the increase of MoS2 content, the composite with 10%MoS2 has a low and stable coefficient at load of 30~50N. The wear rate of composite with 10%MoS2 at load of 50N and sliding speed of 0.69m/s has a sharp increase and there wasn’t mechanically mixed layer(MML) present; the composites at load of 30N and sliding speed of 0.69m/s have low and stable wear rates and there were MML present with wavy shape across entire wear track.
GeoScaler: Generalization tool (with a supplementary user guide in French)
Authors: Huot-Vézina G , Boivin R , Smirnoff A , Paradis S
J
Published: March 2017

The GeoScaler generalization tool helps any user of Arc GIS software to perform a generalization process, from surficial or bedrock based data, in any given scale change.
Horizontal gradient of gravity anomalies map, Canada
Authors: Jobin D M , Véronneau M , Miles W
Published: March 2017

The horizontal gradient of gravity anomalies map of Canada shows variations in the gravity field caused by lateral variations in the density of Earth's crust and upper mantle that reflect differences in composition and thickness. Systematic gravity mapping began
in Canada in 1944 and is ongoing. All Canadian gravity data are tied to the International Gravity Standardization Network 1971 (IGSN71) to create a coherent dataset at the global scale. Local gravity anomalies result from the juxtaposition of relatively high- and low-density rock types. The
horizontal gradient achieves local maxima over or near contacts between rock units with different density.