scholarly journals Structure of Molten Alkali Chlorides at Charged Interfaces and the Prediction and Interpretation of Their X-ray Reflectivity

2021 ◽  
Author(s):  
Waruni V. Karunaratne ◽  
Shobha Sharma ◽  
Benjamin M. Ocko ◽  
Claudio J. Margulis
Keyword(s):  
X Ray ◽  
Alkali Chlorides

scholarly journals Effect of Melt Composition on the Reaction of Uranium Dioxide with Hydrogen Chloride in Molten Alkali Chlorides

2007 ◽  
Vol 62 (10-11) ◽  
pp. 671-676 ◽  
Author(s):  
Vladimir A. Volkovich ◽  
Ilya B. Polovov ◽  
Boris D. Vasin ◽  
Trevor R. Griffiths ◽  
Clint A. Sharrad ◽  
...  
Keyword(s):  
Hydrogen Chloride ◽  
Uranium Dioxide ◽  
Reaction Products ◽  
Alkali Cations ◽  
Alkali Chloride ◽  
X Ray ◽  
Chloride Melts ◽  
Melt Composition ◽  
Alkali Chlorides ◽  
X Ray Absorption

The reaction of uranium dioxide with excess hydrogen chloride in alkali chloride melts (LiCl, 3LiCl-2KCl, NaCl-KCl and NaCl-2CsCl) has been studied between 450 and 750◦C, and the reaction products were characterized by electronic absorption and X-ray absorption spectroscopy. Uranium( V), [UO2Cl4]3−, and uranium(IV), [UCl6]2−, species were formed. They depended upon the temperature and the radius of the alkali cations present. Uranium(V) ions predominated in melts with small cations (LiCl and 3LiCl-2KCl).

Detailed Studies on the High Temperature Corrosion Reactions between Potassium Chloride and Metallic Chromium

2011 ◽  
Vol 696 ◽  
pp. 218-223 ◽  
Author(s):  
Juho Lehmusto ◽  
Patrik Yrjas ◽  
Bengt Johan Skrifvars ◽  
Mikko Hupa
Keyword(s):  
Potassium Chloride ◽  
Chromium Oxide ◽  
Alkali Metals ◽  
Potassium Dichromate ◽  
Potassium Chromate ◽  
Detailed Knowledge ◽  
Tube Material ◽  
X Ray ◽  
The One ◽  
Alkali Chlorides

Recovery of energy from biomass and various waste–derived fuels by combustion has become important due to reduction of detrimental CO2 emissions. Biomass does, however, release significant amounts of chlorine and alkali metals, as e.g. HCl(g), KCl(g), KOH(g) and NaCl(g), into the gas phase during combustion. The alkali chlorides may cause deposits on superheater tubes, which interfere with operation and can lead to corrosion and/or blockage of the gas path. To prevent and diminish the problems mentioned above, better and more detailed knowledge of the reactions between potassium chloride and the tube materials during combustion is needed. These materials commonly contain, among other metals, chromium, which is thought to protect the rest of the material since it forms a very dense but thin oxide layer on the surface of the tube material. It has been suggested that the reaction between solid or partly molten KCl and chromium oxide is the one responsible for starting the complex series of corrosion reactions. In this work, the overall reaction between potassium chloride and chromium was studied through partial reactions with compounds known to participate to the overall reaction or to be formed during it. The reactions were studied in synthetic air by heating sample mixtures in a DTA/TGA (Differential Thermal Analysis/ Thermogravimetric Analysis) apparatus. Selected samples were also studied and analyzed with a scanning electron microscope equipped with an energy dispersive x-ray analyzer (SEM/EDXA). Under the used conditions both potassium chloride and potassium chromate reacted with pure chromium and chromium oxide. In the case of chromium, chromium oxide was formed via the formation of potassium chromate. In reactions including chromium oxide as reactant also potassium dichromate was detected.

Equilibrium decomposition pressures of the compounds Cs2ZrCl6 and Cs2HfCl6 and X-ray identification of Na2HfCl6, K2HfCl6, and Cs2HfCl6

1983 ◽  
Vol 61 (9) ◽  
pp. 2183-2188 ◽  
Author(s):  
G. J. Kipouros ◽  
S. N. Flengas
Keyword(s):  
Vapour Pressure ◽  
Thermodynamic Data ◽  
Pressure Measurements ◽  
Free Energies ◽  
Chemical Equilibria ◽  
X Ray ◽  
Selective Reactivity ◽  
Separating Agents ◽  
Alkali Chlorides

The chemical equilibria representing the reactions[Formula: see text]and[Formula: see text]were investigated by direct vapour pressure measurements and thermodynamic data such as free energies and enthalpies of reaction have been calculated. The X-ray powder patterns of the compounds Na2HfCl6, K2HfCl6, and Cs2HfCl6 are also reported.With reference to the separation of Hf from Zr by a recently developed process based on the selective reactivity of ZrCl4 and HfCl4 vapours with alkali chlorides, it is shown that the efficiency of alkali chlorides as separating agents increases in the order CsCl → LiCl → NaCl → KCl.

Space and Time Distribution of Hard X-Ray Emission in a Loop at the Beginning of a Flare

1994 ◽  
Vol 144 ◽  
pp. 275-277
Author(s):  
M. Karlický ◽  
J. C. Hénoux
Keyword(s):  
Time Distribution ◽  
Electron Bombardment ◽  
Spatial Evolution ◽  
Superthermal Electrons ◽  
Flare Loop ◽  
X Ray ◽  
Superthermal Electron ◽  
Flare Loops ◽  
Chromospheric Evaporation ◽  
Temporal And Spatial

AbstractUsing a new ID hybrid model of the electron bombardment in flare loops, we study not only the evolution of densities, plasma velocities and temperatures in the loop, but also the temporal and spatial evolution of hard X-ray emission. In the present paper a continuous bombardment by electrons isotropically accelerated at the top of flare loop with a power-law injection distribution function is considered. The computations include the effects of the return-current that reduces significantly the depth of the chromospheric layer which is evaporated. The present modelling is made with superthermal electron parameters corresponding to the classical resistivity regime for an input energy flux of superthermal electrons of 109erg cm−2s−1. It was found that due to the electron bombardment the two chromospheric evaporation waves are generated at both feet of the loop and they propagate up to the top, where they collide and cause temporary density and hard X-ray enhancements.

Some Problems in Understanding the Solar Corona

1994 ◽  
Vol 144 ◽  
pp. 1-9
Author(s):  
A. H. Gabriel
Keyword(s):  
Solar Corona ◽  
Solar Atmosphere ◽  
Theoretical Modelling ◽  
Total System ◽  
Major Advance ◽  
X Ray ◽  
Proper Perspective ◽  
Space Observations

The development of the physics of the solar atmosphere during the last 50 years has been greatly influenced by the increasing capability of observations made from space. Access to images and spectra of the hotter plasma in the UV, XUV and X-ray regions provided a major advance over the few coronal forbidden lines seen in the visible and enabled the cooler chromospheric and photospheric plasma to be seen in its proper perspective, as part of a total system. In this way space observations have stimulated new and important advances, not only in space but also in ground-based observations and theoretical modelling, so that today we find a well-balanced harmony between the three techniques.

White-Light Coronal Structures: Streamers and CMEs

1994 ◽  
Vol 144 ◽  
pp. 82
Author(s):  
E. Hildner
Keyword(s):  
Emission Line ◽  
Electron Density ◽  
White Light ◽  
Coronal Mass Ejections ◽  
X Rays ◽  
Solar Cycles ◽  
Temperature Function ◽  
X Ray ◽  
Eclipse Observations ◽  
Coronal Structures

AbstractOver the last twenty years, orbiting coronagraphs have vastly increased the amount of observational material for the whitelight corona. Spanning almost two solar cycles, and augmented by ground-based K-coronameter, emission-line, and eclipse observations, these data allow us to assess,inter alia: the typical and atypical behavior of the corona; how the corona evolves on time scales from minutes to a decade; and (in some respects) the relation between photospheric, coronal, and interplanetary features. This talk will review recent results on these three topics. A remark or two will attempt to relate the whitelight corona between 1.5 and 6 R⊙to the corona seen at lower altitudes in soft X-rays (e.g., with Yohkoh). The whitelight emission depends only on integrated electron density independent of temperature, whereas the soft X-ray emission depends upon the integral of electron density squared times a temperature function. The properties of coronal mass ejections (CMEs) will be reviewed briefly and their relationships to other solar and interplanetary phenomena will be noted.

Iron K-Line Emission from X-Ray Binaries

1988 ◽  
Vol 102 ◽  
pp. 47-50
Author(s):  
K. Masai ◽  
S. Hayakawa ◽  
F. Nagase
Keyword(s):  
Accretion Disk ◽  
Radiative Recombination ◽  
Characteristic Temperature ◽  
Line Emission ◽  
Ionization Front ◽  
Continuum Radiation ◽  
X Ray ◽  
Low Mass ◽  
X Ray Binaries

AbstractEmission mechanisms of the iron Kα-lines in X-ray binaries are discussed in relation with the characteristic temperature Txof continuum radiation thereof. The 6.7 keV line is ascribed to radiative recombination followed by cascades in a corona of ∼ 100 eV formed above the accretion disk. This mechanism is attained for Tx≲ 10 keV as observed for low mass X-ray binaries. The 6.4 keV line observed for binary X-ray pulsars with Tx> 10 keV is likely due to fluorescence outside the He II ionization front.

Diagnostics of Gold Laser Plasmas

1988 ◽  
Vol 102 ◽  
pp. 357-360
Author(s):  
J.C. Gauthier ◽  
J.P. Geindre ◽  
P. Monier ◽  
C. Chenais-Popovics ◽  
N. Tragin ◽  
...  
Keyword(s):  
Experimental Results ◽  
Pure Gold ◽  
Electronic Temperature ◽  
X Ray ◽  
Laser Plasmas ◽  
Collisional Radiative Model ◽  
Radiative Model

AbstractIn order to achieve a nickel-like X ray laser scheme we need a tool to determine the parameters which characterise the high-Z plasma. The aim of this work is to study gold laser plasmas and to compare experimental results to a collisional-radiative model which describes nickel-like ions. The electronic temperature and density are measured by the emission of an aluminium tracer. They are compared to the predictions of the nickel-like model for pure gold. The results show that the density and temperature can be estimated in a pure gold plasma.

Axial Observation of X-Ray Spectra from a Beam-Foil Source

1988 ◽  
Vol 102 ◽  
pp. 339-342
Author(s):  
J.M. Laming ◽  
J.D. Silver ◽  
R. Barnsley ◽  
J. Dunn ◽  
K.D. Evans ◽  
...  
Keyword(s):  
Spectral Resolution ◽  
Heavy Ion ◽  
Ion Beams ◽  
Beam Axis ◽  
Doppler Broadening ◽  
X Ray ◽  
Beam Foil

AbstractNew observations of x-ray spectra from foil-excited heavy ion beams are reported. By observing the target in a direction along the beam axis, an improvement in spectral resolution, δλ/λ, by about a factor of two is achieved, due to the reduced Doppler broadening in this geometry.

Observed and Theoretical Spectra in the 10–100Å Interval

1988 ◽  
Vol 102 ◽  
pp. 259-261
Author(s):  
W.A. Brown ◽  
M.E. Bruner ◽  
L.W. Acton
Keyword(s):  
Sounding Rocket ◽  
Full Spectrum ◽  
X Ray

AbstractThe soft x-ray spectra recorded in two sounding rocket flights in 1982 and 1985 are compared with with predicted spectra. The poster presents the processed densitometer trace of the full spectrum together with the new spectrum from the 1985 experiment. This note compares the intensities of the lines with predictions.

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