scholarly journals X-ray diffraction of dynamically compressed matter on Sandia?s Z Pulsed Power Facility.

2019 ◽  
Author(s):  
Tommy Ao ◽  
Marius Schollmeier ◽  
Patrycja E Kalita ◽  
Paul D Gard ◽  
James Robert Williams ◽  
...  
Keyword(s):  
Pulsed Power ◽  
X Ray Diffraction ◽  
X Ray ◽  
Power Facility

Study on phase transformation in Tin under dynamic compression

2019 ◽  
Author(s):  
Camille Chauvin ◽  
Frédéric Zucchini ◽  
David Palma de Barros
Keyword(s):  
Phase Transformations ◽  
Shock Loading ◽  
Initial Conditions ◽  
Dynamic Compression ◽  
Polymorphic Transition ◽  
Pulsed Power ◽  
X Ray Diffraction ◽  
Velocity Measurements ◽  
Isentropic Compression ◽  
X Ray

Abstract We propose to study experimentally the polymorphic transition of Tin under dynamic compression. These transformations have been investigated for a long time through usual velocity measurements under shock from ambient condition. At CEA Gramat we have improved our understanding of such phase transformations through both experimental and theoretical means. Experimental velocity measurements have long suggested that non equilibrium behavior and kinetics is an important part of the dynamic compression response of materials undergoing phase transformations. Empirical kinetic models can in many cases reproduce the experimental velocity profiles, but without clearly identifying the nature of the transition. For nearly two decades, the CEA Gramat operates several gas guns for shock loading and high pulsed power (HPP) drivers dedicated to Isentropic Compression Experiments (ICE) up to several GPa. These experimental devices and associated diagnostics (velocimetry and temperature measurements and x-ray diffraction experiments) help to begin to study kinetics under dynamic transition in a more rigorous manner. We have used these experiments to examine various compression paths and have used the results to improve equation of state (EOS) models incorporated in our numerical codes. The latter can be used to run simulations starting with ambient initial conditions, then load metallic materials from various non ambient initial temperatures. This can significantly extend the range of our studies into previously unexplored thermodynamic paths. We propose to describe our preheating devices for gas gun experiments and our HPP driver, and to present our preliminary results on shock loading and on isentropic compression at various initial temperatures, to explore the phase diagram of Tin. In addition, we present the design of promising testing on X-ray diffraction under shock to help to develop a more physical kinetic model relying on nucleation and growth mechanisms, which are implemented in our continuum level codes.

scholarly journals A 7.2 keV spherical x-ray crystal backlighter for two-frame, two-color backlighting at Sandia’s Z Pulsed Power Facility

2017 ◽  
Vol 88 (10) ◽  
pp. 103503 ◽  
Author(s):  
M. S. Schollmeier ◽  
P. F. Knapp ◽  
D. J. Ampleford ◽  
E. C. Harding ◽  
C. A. Jennings ◽  
...  
Keyword(s):  
Pulsed Power ◽  
X Ray ◽  
Power Facility

Evidence of Soft X-Ray Lasing in SIGNAL Pulsed-Power Facility Experiments With Argon Capillary Plasma

2006 ◽  
Vol 34 (5) ◽  
pp. 2368-2376 ◽  
Author(s):  
V.I. Ostashev ◽  
A.M. Gafarov ◽  
V.Y. Politov ◽  
A.N. Shushlebin ◽  
L.V. Antonova
Keyword(s):  
Pulsed Power ◽  
X Ray ◽  
Power Facility

scholarly journals Upgrading Wolter Imagers for X-Ray Diagnostics in the Z Pulsed-Power Facility at Sandia National Laboratories.

2020 ◽  
Author(s):  
J Vogel ◽  
B Kozioziemski ◽  
C Walton ◽  
J Ayers ◽  
Perry Bell ◽  
...  
Keyword(s):  
Pulsed Power ◽  
X Ray ◽  
Power Facility

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

Ribosome Structural Organization

1974 ◽  
Vol 32 ◽  
pp. 332-333
Author(s):  
James A. Lake
Keyword(s):  
Ribosomal Proteins ◽  
Structural Organization ◽  
Three Dimensional ◽  
Small Subunit ◽  
Structural Studies ◽  
X Ray Diffraction ◽  
Specific Antibodies ◽  
X Ray ◽  
E Coli ◽  
Complete Sequences

The understanding of ribosome structure has advanced considerably in the last several years. Biochemists have characterized the constituent proteins and rRNA's of ribosomes. Complete sequences have been determined for some ribosomal proteins and specific antibodies have been prepared against all E. coli small subunit proteins. In addition, a number of naturally occuring systems of three dimensional ribosome crystals which are suitable for structural studies have been observed in eukaryotes. Although the crystals are, in general, too small for X-ray diffraction, their size is ideal for electron microscopy.

Electron Microscopy of Human Gallstones

1971 ◽  
Vol 29 ◽  
pp. 296-297
Author(s):  
C. Wolpers ◽  
R. Blaschke
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Bile Pigment ◽  
X Ray Diffraction ◽  
Triclinic Crystal System ◽  
X Ray ◽  
Follow Up Study ◽  
Infra Red ◽  
Main Components

Scanning microscopy was used to study the surface of human gallstones and the surface of fractures. The specimens were obtained by operation, washed with water, dried at room temperature and shadowcasted with carbon and aluminum. Most of the specimens belong to patients from a series of X-ray follow-up study, examined during the last twenty years. So it was possible to evaluate approximately the age of these gallstones and to get information on the intensity of growing and solving.Cholesterol, a group of bile pigment substances and different salts of calcium, are the main components of human gallstones. By X-ray diffraction technique, infra-red spectroscopy and by chemical analysis it was demonstrated that all three components can be found in any gallstone. In the presence of water cholesterol crystallizes in pane-like plates of the triclinic crystal system.

High Resolution Replication of Organoclay Surfaces

1982 ◽  
Vol 40 ◽  
pp. 576-577
Author(s):  
W. W. Barker ◽  
W. E. Rigsby ◽  
V. J. Hurst ◽  
W. J. Humphreys
Keyword(s):  
Clay Mineral ◽  
Organic Molecule ◽  
Organic Molecules ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
X Ray ◽  
Naturally Occurring ◽  
Silicate Layers ◽  
Mineral Identification

Experimental clay mineral-organic molecule complexes long have been known and some of them have been extensively studied by X-ray diffraction methods. The organic molecules are adsorbed onto the surfaces of the clay minerals, or intercalated between the silicate layers. Natural organo-clays also are widely recognized but generally have not been well characterized. Widely used techniques for clay mineral identification involve treatment of the sample with H2 O2 or other oxidant to destroy any associated organics. This generally simplifies and intensifies the XRD pattern of the clay residue, but helps little with the characterization of the original organoclay. Adequate techniques for the direct observation of synthetic and naturally occurring organoclays are yet to be developed.

Electron Microscopy of Shock Loaded Polycrystalline Beryllium

1974 ◽  
Vol 32 ◽  
pp. 506-507 ◽  
Author(s):  
J. M. Galbraith ◽  
L. E. Murr ◽  
A. L. Stevens
Keyword(s):  
Electron Microscopy ◽  
Wave Propagation ◽  
Structural Change ◽  
Single Crystal ◽  
Diffraction Pattern ◽  
Shock Loading ◽  
Slip Systems ◽  
Compression Tests ◽  
X Ray Diffraction ◽  
X Ray

Uniaxial compression tests and hydrostatic tests at pressures up to 27 kbars have been performed to determine operating slip systems in single crystal and polycrystal1ine beryllium. A recent study has been made of wave propagation in single crystal beryllium by shock loading to selectively activate various slip systems, and this has been followed by a study of wave propagation and spallation in textured, polycrystal1ine beryllium. An alteration in the X-ray diffraction pattern has been noted after shock loading, but this alteration has not yet been correlated with any structural change occurring during shock loading of polycrystal1ine beryllium.This study is being conducted in an effort to characterize the effects of shock loading on textured, polycrystal1ine beryllium. Samples were fabricated from a billet of Kawecki-Berylco hot pressed HP-10 beryllium.

Chemical modification of the bacterial wall to determine sites of metal deposition

1978 ◽  
Vol 36 (2) ◽  
pp. 350-351
Author(s):  
T. J. Beveridge
Keyword(s):  
Electron Scattering ◽  
Metal Salt ◽  
Metal Deposition ◽  
Suitable Model ◽  
X Ray Diffraction ◽  
Subtilis Cell ◽  
Thin Sections ◽  
X Ray ◽  
Section Data ◽  
Metal Impregnation

The Bacillus subtilis cell wall provides a protective sacculus about the vital constituents of the bacterium and consists of a collection of anionic hetero- and homopolymers which are mainly polysaccharidic. We recently demonstrated that unfixed walls were able to trap and retain substantial amounts of metal when suspended in aqueous metal salt solutions. These walls were briefly mixed with low concentration metal solutions (5mM for 10 min at 22°C), were well washed with deionized distilled water, and the quantity of metal uptake (atomic absorption and X-ray fluorescence), the type of staining response (electron scattering profile of thin-sections), and the crystallinity of the deposition product (X-ray diffraction of embedded specimens) determined.Since most biological material possesses little electron scattering ability electron microscopists have been forced to depend on heavy metal impregnation of the specimen before obtaining thin-section data. Our experience with these walls suggested that they may provide a suitable model system with which to study the sites of reaction for this metal deposition.

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