Imprints of a high-velocity wind on the soft X-ray spectrum of PG1211+143

This present work investigates the effects of sintering temperature on densification, mechanical properties and microstructure of Al-based alloy pressed by high-velocity compaction. The green samples were heated under the flow of high pure (99.99 wt%) N2. The heating rate was 4 °C/min before 315 °C. For reducing the residual stress, the samples were isothermally held for one h. Then, the specimens were respectively heated at the rate of 10 °C/min to the temperature between 540 °C and 700 °C, held for one h, and then furnace-cooled to the room temperature. Results indicate that when the sintered temperature was 640 °C, both the sintered density and mechanical properties was optimum. Differential Scanning Calorimetry, X-ray diffraction of sintered samples, Scanning Electron Microscopy, Energy Dispersive Spectroscopy, and Transmission Electron Microscope were used to analyse the microstructure and phases.

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The X-ray view of the Wolf-Rayet stars

Symposium - International Astronomical Union ◽

10.1017/s0074180900202428 ◽

1995 ◽

Vol 163 ◽

pp. 429-437

Author(s):

A.M.T. Pollock

Keyword(s):

High Velocity ◽

X Ray ◽

Wide Range ◽

Colliding Winds

Ever since the earliest work, X-ray observations have been central in the chequered development of the study of interacting high-velocity winds in binaries. This review assesses how confidently the observations of Wolf-Rayet stars may be interpreted as the result of colliding winds, drawing attention to the wide range of X-ray luminosities even among the relatively bright binaries. Although the data do not generally conform to the simplest binary models, some suggestions are made to reconcile theory and observation.

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Microstructure, Mechanical Properties and Wear Behavior of High-Velocity Oxygen-Fuel (HVOF) Sprayed (Cr3C2-NiCr+Al) Composite Coating on Ductile Cast Iron

Coatings ◽

10.3390/coatings9120840 ◽

2019 ◽

Vol 9 (12) ◽

pp. 840 ◽

Cited By ~ 1

Author(s):

Marzanna Ksiazek ◽

Lukasz Boron ◽

Adam Tchorz

Keyword(s):

Cast Iron ◽

Electron Microscope ◽

High Velocity ◽

Bending Strength ◽

Wear Behavior ◽

Ductile Cast Iron ◽

Wear Behaviour ◽

Wear Properties ◽

Alloy Matrix ◽

X Ray

In the present work Cr3C2-NiCr powder containing Al particles was deposited on ductile cast iron with high-velocity oxy-fuel (HVOF) thermal spray coating technique. An investigation was conducted to determine the role of Al particles in the Cr3C2-NiCr coating produced with HVOF technique on microstructure, mechanical and wear properties in a system Cr2C3-NiCr coating/ductile cast iron. The microstructure of the HVOF-sprayed Cr3C2-NiCr+Al coating was characterized by light microscopy, X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and energy dispersive X-ray spectroscopy (EDS). Microstructure analysis reveals the formation of coating with low porosity, good adhesion to the substrate and dense structure with irregularly shaped particles of Al arranged in strips and finely fragmented Cr3C2 particles embedded in a nanocrystalline Ni-Cr alloy matrix. In addition, the results were discussed in reference to examination of bending strength considering cracking and delamination in the system of (Cr3C2-NiCr+Al)/ductile cast iron as well as microhardness and wear resistance of the coating. It was found that the addition of Al particles significantly increased resistance to cracking and wear behaviour in the studied system.

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The AGN dependence on cluster mass

Proceedings of the International Astronomical Union ◽

10.1017/s1743921318005124 ◽

2018 ◽

Vol 14 (S342) ◽

pp. 145-148

Author(s):

Elias Koulouridis ◽

Keyword(s):

Galaxy Clusters ◽

High Velocity ◽

High Redshift ◽

High Mass ◽

X Ray ◽

Cluster Galaxies ◽

Cluster Mass ◽

Bona Fide ◽

Low Mass ◽

Velocity Dispersions

AbstractWe present the results of a study of the AGN density in a homogeneous and well studied sample of 167 bona-fide X-ray galaxy clusters (0.1<z<0.5). Our aim is to study the AGN activity in 167 XXL X-ray galaxy clusters as a function of the cluster mass and the location of the AGN in the cluster. We report a significant AGN excess in our low-mass cluster sub-sample between 0.5r500 and 2r500. In contrast, the high-mass sub-sample presents no AGN excess. The AGN excess in poor clusters indicates AGN triggering, supporting previous studies that reported enhanced galaxy merging in the cluster outskirts. This effect is probably prevented by high velocity dispersions in high-mass clusters. Comparing also with previous studies of massive or high-redshift clusters, we conclude that the AGN fraction in cluster galaxies anti-correlates strongly with cluster mass.

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The velocity field of the Lyra complex

Astronomy and Astrophysics ◽

10.1051/0004-6361/201936466 ◽

2020 ◽

Vol 633 ◽

pp. A108 ◽

Cited By ~ 1

Author(s):

M. Girardi ◽

W. Boschin ◽

S. De Grandi ◽

M. Longhetti ◽

S. Clavico ◽

...

Keyword(s):

Velocity Field ◽

High Velocity ◽

Major Axis ◽

Dynamical Analysis ◽

Cluster Assembly ◽

X Ray ◽

Radio Data ◽

The Galaxy ◽

A Minor ◽

Complex Scenario

Context. The formation of cosmic structures culminates with the assembly of galaxy clusters, a process that is quite different from cluster to cluster. Aims. We present the study of the structure and dynamics of the Lyra complex, consisting of the two clusters RXC J1825.3+3026 and CIZA J1824.1+3029, which was very recently studied by using both X-ray and radio data. Methods. This is the first analysis based on the kinematics of member galaxies. New spectroscopic data for 285 galaxies were acquired at the Italian Telescopio Nazionale Galileo and were used in combination with PanSTARRS photometry. The result of our member selection is a sample of 198 galaxies. Results. For RXCJ1825 and CIZAJ1824 we report the redshifts, z = 0.0645 and z = 0.0708, the first estimates of velocity dispersion, σv = 995+131−125 km s−1 and σv = 700 ± 50 km s−1, and of dynamical mass, M200 = 1.1 ± 0.4 × 1015 M⊙ and M200 = 4 ± 0.1 × 1014 M⊙. The past assembly of RXCJ1825 is traced by the two dominant galaxies, which are both aligned with the major axis of the galaxy distribution along the east–west direction, and by a minor northeast substructure. We also detect a quite peculiar high velocity field in the southwest region of the Lyra complex. This feature is likely related to a very luminous galaxy, which is characterized by a high velocity. This galaxy is suggested to be the central galaxy of a group that is in interaction with RXCJ1825 according to very recent studies based on X-ray and radio data. The redshift of the whole Lyra complex is z = 0.067. Assuming that the redshift difference between RXCJ1825 and CIZAJ1824 is due to the relative kinematics, the projected distance between the cluster centers is D ∼ 1.3 Mpc and the line–of–sight velocity difference is ∼1750 km s−1. A dynamical analysis of the system shows that the two clusters are likely to be gravitationally bound in a pre-merger phase, and that CIZAJ1824 is moving toward RXCJ1825. Conclusions. Our results corroborate a picture where the Lyra region is the place of a very complex scenario of cluster assembly.

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Hot Shocked Gas Along the Helical Jets of NGC 4258

International Astronomical Union Colloquium ◽

10.1017/s0252921100022764 ◽

1995 ◽

Vol 149 ◽

pp. 118-122

Author(s):

G. Cecil

Keyword(s):

High Velocity ◽

Seyfert Galaxy ◽

Molecular Gas ◽

X Ray ◽

Fabry Perot

AbstractI summarize the results of our multifrequency study of the helically twisted jets in the Seyfert galaxy NGC 4258. [N II], Hα, and [O III] Fabry-Perot datacubes obtained with the HIFI system on the U. Hawaii 2.2m telescope form the basis of this work. ROSAT x-ray multiband images (HRI & PSPC), CO spectra, and unpublished VLA 6 and 20 cm maps are correlated with these spectral grids. Together these data reveal clear signatures of high-velocity (> 300 km s−1) shocks along the jets that suggest efficient entrainment of ambient molecular gas.

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Understanding the Influence of High Velocity Thermal Spray Techniques on the Properties of Different Anti-Wear WC-Based Coatings

Coatings ◽

10.3390/coatings10121157 ◽

2020 ◽

Vol 10 (12) ◽

pp. 1157

Author(s):

Andrea Garfias Bulnes ◽

Vicente Albaladejo Fuentes ◽

Irene Garcia Cano ◽

Sergi Dosta

Keyword(s):

Grain Size ◽

Corrosion Resistance ◽

Abrasive Wear ◽

Thermal Spray ◽

High Velocity ◽

Metallic Matrix ◽

High Hardness ◽

Hard Metal ◽

Characterization Methods ◽

X Ray

This work analyzes the differences found in hard metal coatings produced by two high velocity thermal spray techniques, namely high velocity oxy-fuel (HVOF) and high velocity air-fuel (HVAF). Additionally, the effect of the metallic matrix and ceramic composition and the original carbide grain size on coating properties is compared to the most studied standard reference material sprayed by HVOF, WC-Co. For this evaluation, the physical properties of the coatings, including feedstock characteristics, porosity, thickness, roughness, hardness, and phase composition were investigated. Several characterization methods were used for this purpose: optical microscopy (OM), scanning electronic microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDS), and X-ray Diffraction (XRD), among others. The final performance (abrasive wear and corrosion resistance) shown by the coatings obtained by these two methodologies was also analyzed. Thus, the abrasive wear resistance was analyzed by the rubber-wheel test, while the corrosion resistance was characterized with electrochemical methods. The characterization results obtained clearly showed that the coatings exhibit different microstructures according to feedstock powder characteristics (carbide grain size and/or composition) and the thermal spray process used for its deposition. Thus, the incorporation of WB to the cermet composition led to a high hardness coating, and the complementary hardness and toughness of the WC-Co coatings justify its better abrasion resistance. The presence of Ni on the metal matrix increases the free corrosion potential of the coating to more noble region. However, the WC-Co coatings show a lower corrosion rate and hence a higher protective performance than the rest of the coatings.

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Fe-Based Amorphous/Nanocrystalline Coating on AZ91 Magnesium Alloy Substrate Deposited by Automatic High Velocity Arc Spraying

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.418-420.786 ◽

2011 ◽

Vol 418-420 ◽

pp. 786-791 ◽

Cited By ~ 1

Author(s):

Lin Lei Wang ◽

Xiu Bing Liang ◽

Shi Cheng Wei ◽

Yong Xiong Chen ◽

Wei Guo ◽

...

Keyword(s):

Electron Microscopy ◽

Elastic Modulus ◽

Magnesium Alloy ◽

High Velocity ◽

Arc Spraying ◽

Az91 Magnesium Alloy ◽

X Ray ◽

Nanocrystalline Coating ◽

High Velocity Arc Spraying ◽

Az91 Magnesium

An automatic high velocity arc spraying process was used to deposit a type of FeCrBSiMoNbW amorphous/nanocrystalline coating with substrate of AZ91 magnesium alloy. The microstructure of the coating was characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) equipped with energy dispersive X-ray analysis (EDAX). The coating is about 250μm in thickness with low porosity and oxids. The results show that the microstructure of the coating can be classified into two regions, namely, a full amorphous phase region and homogeneous dispersion of α-Fe (Cr) nanocrystals with 30-80 nm in a residual amorphous region. Mechanical properties, such as nano-hardness, elastic modulus, were analyzed. The experimental results show that the coating has high nano-hardness and elastic modulus. The friction and wear experiments were operated on UMT-2 micro friction tester. The relative wear resistance of the FeCrBSiMoNbW coating is about 2 times higher than that of the conventional 3Cr13 coating under the same conditions. The main wear mechanism of the amorphous/nanocrystalline coating is the typical brittle spalling.

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