DETERMINATION OF GALAXY DISTRIBUTION WITH STATISTICAL MOMENTS

In this report we discuss topological studies of large scale structure of the Universe (LSS) from XMM-Newton, Sloan Digital Sky Survey and simulated data of galaxy distribution. Early works in this mentioned field were based on genus statistics, which is averaged curvature of isosurface of smoothed density field. Later, significant number of other methods was developed. This comprise Euler characteristics, Minkowski functionals, Voronoi clustering, alpha shapes, Delanuay tesselation, Morse theory, Hessian matrix and Soneira-Peebles models. In practice, modern topology methods are reducedto calculation of the three Betti numbers which shall be interpreted as a number of galaxy clusters, filaments and voids. Such an approach was applied by different authors both for simulated and observed LSS data. Topology methods are generally verified using LSS simulations. Observational data normally includes SDSS, CFHTLS and other surveys. These data have many systematical and statistical errors and gaps. Furthermore, there is also a problem of underlying dark matter distribution. The situation is not better in relation to calculations of the power spectrum and its power law index which does not provide a clear picture as well. In this work we propose some tools to solve above problems. First, we performed topology description of simple LSS models such as cubic, graphite-like and random Gaussian distribution of matter. Our next idea is to set a task for LSS topology assessment using X-ray observations of the galaxies. Although, here could be a major complication due to current lack of detected high energy emitting galaxies. Nevertheless, we are expecting to get sufficient results in the future encouraging comprehensive X-ray data. Here we present analysis of statistical moments for four galaxy samples and compare them with the behavior of Betti numbers. Finally, we consider the options of applying artificial neural networks to observed galaxies and fill the data deficiency. This shall enable to define topology at least for superimposed superclusters and other LSS elements.

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Investigation of Residual Stress/Strain and Texture in a Large Dissimilar Metal Weld Using Synchrotron Radiation and Neutrons

Materials Science Forum ◽

10.4028/www.scientific.net/msf.772.193 ◽

2013 ◽

Vol 772 ◽

pp. 193-199 ◽

Cited By ~ 1

Author(s):

Carsten Ohms ◽

Rene V. Martins

Keyword(s):

Synchrotron Radiation ◽

Neutron Diffraction ◽

Residual Stresses ◽

Large Scale ◽

High Energy ◽

X Ray Diffraction ◽

Butt Weld ◽

X Ray ◽

Component Size ◽

Thin Slice

Bi-metallic piping welds are frequently used in light water nuclear reactors to connect ferritic steel pressure vessel nozzles to austenitic stainless steel primary cooling piping systems. An important aspect for the integrity of such welds is the presence of residual stresses. Measurement of these residual stresses presents a considerable challenge because of the component size and because of the material heterogeneity in the weld regions. The specimen investigated here was a thin slice cut from a full-scale bi-metallic piping weld mock-up. A similar mock-up had previously been investigated by neutron diffraction within a European research project called ADIMEW. However, at that time, due to the wall thickness of the pipe, stress and spatial resolution of the measurements were severely restricted. One aim of the present investigations by high energy synchrotron radiation and neutrons used on this thin slice was to determine whether such measurements would render a valid representation of the axial strains and stresses in the uncut large-scale structure. The advantage of the small specimen was, apart from the easier manipulation, the fact that measurement times facilitated a high density of measurements across large parts of the test piece in a reasonable time. Furthermore, the recording of complete diffraction patterns within the accessible diffraction angle range by synchrotron X-ray diffraction permitted mapping the texture variations. The strain and stress results obtained are presented and compared for the neutron and synchrotron X-ray diffraction measurements. A strong variation of the texture pole orientations is observed in the weld regions which could be attributed to individual weld torch passes. The effect of specimen rocking on the scatter of the diffraction data in the butt weld region is assessed during the neutron diffraction measurements.

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The High-energy X-ray Background and Limits on Large Scale Structure

Large Scale Structures of the Universe ◽

10.1007/978-94-009-2995-1_28 ◽

1988 ◽

pp. 203-206

Author(s):

A. Mészáros ◽

P. Mészáros

Keyword(s):

Large Scale ◽

Large Scale Structure ◽

High Energy ◽

Scale Structure ◽

X Ray ◽

X Ray Background

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Alternatives to the Existence of Large Cooling Flows

International Astronomical Union Colloquium ◽

10.1017/s0252921100012380 ◽

1990 ◽

Vol 115 ◽

pp. 232-239

Author(s):

Wallace Tucker

Keyword(s):

Surface Brightness ◽

Large Scale ◽

Theoretical Calculations ◽

Central Peak ◽

High Energy ◽

Cooling Time ◽

Radiative Cooling ◽

Massive Black Hole ◽

X Ray ◽

Cooling Flows

AbstractArguments against the existence of large scale cooling flows in clusters of galaxies are presented. The evidence for cooling flows is all circumstantial, consisting of observations of cool gas or hot gas with a radiative cooling time less than the Hubble time, or a central peak in the x-ray surface brightness profile. There is no evidence for large quantities (several tens to several hundreds of solar masses per year) of matter actually flowing anywhere. On the contrary, several lines of evidence — stellar dynamics, observations of the amount of star formation, x-ray surface brightness observations, theoretical calculations of the growth of thermal instabilities, the amount of cold gas — suggest that cooling flows, if they exist, must be suppressed by one to two orders of magnitude from the values implied by simple estimates based on the radiative cooling time of the x-ray emitting gas. Two heat sources which might accomplish this — thermal conduction and relativistic particles, are considered and an alternative to the standard model for cooling flows is presented: an accretion flow with feedback wherein the accretion of gas into a massive black hole in the central galaxy generates high energy particles that heat the gas and act to limit the accretion.

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Fast high-energy X-ray imaging for Severe Accidents experiments on the future PLINIUS-2 platform

EPJ Web of Conferences ◽

10.1051/epjconf/201817008003 ◽

2018 ◽

Vol 170 ◽

pp. 08003

Author(s):

L. Berge ◽

N. Estre ◽

D. Tisseur ◽

E. Payan ◽

D. Eck ◽

...

Keyword(s):

Large Scale ◽

Spot Size ◽

High Energy ◽

Simulation Software ◽

Small Scale ◽

Noise Sources ◽

X Ray ◽

X Ray Imaging ◽

The Future ◽

Set Up

The future PLINIUS-2 platform of CEA Cadarache will be dedicated to the study of corium interactions in severe nuclear accidents, and will host innovative large-scale experiments. The Nuclear Measurement Laboratory of CEA Cadarache is in charge of real-time high-energy X-ray imaging set-ups, for the study of the corium-water and corium-sodium interaction, and of the corium stratification process. Imaging such large and high-density objects requires a 15 MeV linear electron accelerator coupled to a tungsten target creating a high-energy Bremsstrahlung X-ray flux, with corresponding dose rate about 100 Gy/min at 1 m. The signal is detected by phosphor screens coupled to high-framerate scientific CMOS cameras. The imaging set-up is established using an experimentally-validated home-made simulation software (MODHERATO). The code computes quantitative radiographic signals from the description of the source, object geometry and composition, detector, and geometrical configuration (magnification factor, etc.). It accounts for several noise sources (photonic and electronic noises, swank and readout noise), and for image blur due to the source spot-size and to the detector unsharpness. In a view to PLINIUS-2, the simulation has been improved to account for the scattered flux, which is expected to be significant. The paper presents the scattered flux calculation using the MCNP transport code, and its integration into the MODHERATO simulation. Then the validation of the improved simulation is presented, through confrontation to real measurement images taken on a small-scale equivalent set-up on the PLINIUS platform. Excellent agreement is achieved. This improved simulation is therefore being used to design the PLINIUS-2 imaging set-ups (source, detectors, cameras, etc.).

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High-Energy X-Ray Compton Scattering Imaging of 18650-Type Lithium-Ion Battery Cell

Condensed Matter ◽

10.3390/condmat4030066 ◽

2019 ◽

Vol 4 (3) ◽

pp. 66 ◽

Cited By ~ 1

Author(s):

Kosuke Suzuki ◽

Ari-Pekka Honkanen ◽

Naruki Tsuji ◽

Kirsi Jalkanen ◽

Jari Koskinen ◽

...

Keyword(s):

Energy Spectrum ◽

Lithium Ion Battery ◽

Compton Scattering ◽

Present Method ◽

Large Scale ◽

Lithium Ion ◽

High Energy ◽

The Other ◽

Battery Cell ◽

X Ray

High-energy synchrotron X-ray Compton scattering imaging was applied to a commercial 18650-type cell, which is a cylindrical lithium-ion battery in wide current use. By measuring the Compton scattering X-ray energy spectrum non-destructively, the lithiation state in both fresh and aged cells was obtained from two different regions of the cell, one near the outer casing and the other near the center of the cell. Our technique has the advantage that it can reveal the lithiation state with a micron-scale spatial resolution even in large cells. The present method enables us to monitor the operation of large-scale cells and can thus accelerate the development of advanced lithium-ion batteries.

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Laser-plasma extreme ultraviolet and soft X-ray sources based on a double stream gas puff target: interaction of the radiation pulses with matter

Opto-Electronics Review ◽

10.1515/oere-2015-0023 ◽

2015 ◽

Vol 23 (2) ◽

Cited By ~ 2

Author(s):

A. Bartnik

Keyword(s):

Large Scale ◽

Extreme Ultraviolet ◽

High Energy ◽

High Energy Density ◽

Small Scale ◽

X Ray ◽

Target Interaction ◽

University Of Technology ◽

Photoionized Plasmas ◽

Intense Radiation

AbstractIn this work a review of investigations concerning interaction of intense extreme ultraviolet (EUV) and soft X-ray (SXR) pulses with matter is presented. The investigations were performed using laser-produced plasma (LPP) EUV/SXR sources based on a double stream gas puff target. The sources are equipped with dedicated collectors allowing for efficient focusing of the EUV/SXR radiation pulses. Intense radiation in a wide spectral range, as well as a quasi-monochromatic radiation can be produced. In the paper different kinds of LPP EUV/SXR sources developed in the Institute of Optoelectronics, Military University of Technology are described.Radiation intensities delivered by the sources are sufficient for different kinds of interaction experiments including EUV/SXR induced ablation, surface treatment, EUV fluorescence or photoionized plasma creation. A brief review of the main results concerning this kind of experiments performed by author of the paper are presented. However, since the LPP sources cannot compete with large scale X-ray sources like synchrotrons, free electron lasers or high energy density plasma sources, it was indicated that some investigations not requiring extreme irradiation parameters can be performed using the small scale installations. Some results, especially concerning low temperature photoionized plasmas are very unique and could be hardly obtained using the large facilities.

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Sources of X-rays from galaxies

Proceedings of the International Astronomical Union ◽

10.1017/s1743921312009039 ◽

2011 ◽

Vol 7 (S284) ◽

pp. 183-192

Author(s):

Q. Daniel Wang

Keyword(s):

Active Galactic Nuclei ◽

Galaxy Evolution ◽

Supernova Remnants ◽

Large Scale ◽

Formation Rate ◽

Galactic Nuclei ◽

High Energy ◽

High Mass ◽

X Rays ◽

X Ray

AbstractGalactic X-ray emission is a manifestation of various high-energy phenomena and processes. The brightest X-ray sources are typically accretion-powered objects: active galactic nuclei and low- or high-mass X-ray binaries. Such objects with X-ray luminosities of ≳ 1037 ergs s−1 can now be detected individually in nearby galaxies. The contributions from fainter discrete sources (including cataclysmic variables, active binaries, young stellar objects, and supernova remnants) are well correlated with the star formation rate or stellar mass of galaxies. The study of discrete X-ray sources is essential to our understanding of stellar evolution, dynamics, and end-products as well as accretion physics. With the subtraction of the discrete source contributions, one can further map out truly diffuse X-ray emission, which can be used to trace the feedback from active galactic nuclei, as well as from stars, both young and old, in the form of stellar winds and supernovae. The X-ray emission efficiency, however, is only about 1% of the energy input rate of the stellar feedback alone. The bulk of the feedback energy is most likely gone with outflows into large-scale galactic halos. Much is yet to be investigated to comprehend the role of such outflows in regulating the ecosystem, hence the evolution of galaxies. Even the mechanism of the diffuse X-ray emission remains quite uncertain. A substantial fraction of the emission cannot arise directly from optically-thin thermal plasma, as commonly assumed, and most likely originates in its charge exchange with neutral gas. These uncertainties underscore our poor understanding of the feedback and its interplay with the galaxy evolution.

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Quantification of Large Scale Micro-X-Ray Fluorescence Elemental Images

Applied Spectroscopy ◽

10.1366/0003702011953928 ◽

2001 ◽

Vol 55 (11) ◽

pp. 1448-1454 ◽

Cited By ~ 3

Author(s):

Christopher G. Worley ◽

George J. Havrilla ◽

Paul S. Dunn

Keyword(s):

Concentration Distribution ◽

Large Scale ◽

Surface Oxidation ◽

Sample Surface ◽

High Energy ◽

Depleted Uranium ◽

Established Method ◽

X Ray ◽

Elemental Concentrations ◽

Relative Differences

Niobium is commonly alloyed with uranium to prevent surface oxidation, and determining how the niobium concentration is distributed throughout a sample is useful in explaining observed material properties. The niobium concentration distribution was determined across the surface of depleted uranium samples using micro-X-ray fluorescence (MXRF). To date, MXRF has been employed primarily as a qualitative tool for determining relative differences in elemental concentrations across a sample surface. Here, a process was developed to convert qualitative MXRF niobium distribution images from depleted uranium samples into images displaying concentration values. Thus, MXRF was utilized to determine elemental concentrations across a surface in a manner similar to that of the established method of electron microprobe X-ray analysis (EMPA). However, MXRF can provide such information from relatively large sample areas many cm2 in size that are too large to examine by the higher spatial resolution technique of EMPA. Although the sample surfaces were polished to the same degree as the standards, little or no sample preparation should be necessary for sample systems where a high energy analyte XRF line can be used for imaging.

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Sunspot Magnetic Fields and High Energy Electrons in Flares

Symposium - International Astronomical Union ◽

10.1017/s007418090002283x ◽

1971 ◽

Vol 43 ◽

pp. 390-396

Author(s):

Tatsuo Takakura

Keyword(s):

Magnetic Fields ◽

Electric Potential ◽

Potential Field ◽

Large Scale ◽

Plasma Waves ◽

High Energy ◽

Ohmic Loss ◽

X Ray ◽

High Energy Electrons ◽

Electric Potential Field

A balloon observation of an impulsive hard X-ray burst on September 27, 1969 showed the size of the source to be one arc minute or less. It was remarkably smaller than the associated Hα flare with a size of 3 arc min.The efficient acceleration of electrons and the trigger of the flares are suggested to be attributed to a large scale electric potential field caused by a gas motion near the photosphere. The primary cause of the onset of flares would be the acceleration of electrons. The electrons excite plasma waves which make the conductivity lower by several orders, so that the electromagnetic energy I2L stored before the onset of the flare would be suddenly converted into the heat due to the ohmic loss.

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