scholarly journals Insight Into Disorder, Stress and Strain of Radiation Damaged Pyrochlores: A Possible Mechanism for the Appearance of Defect Fluorite

2021 ◽  
Vol 9 ◽  
Author(s):  
Sarah C. Finkeldei ◽  
Shirley Chang ◽  
Mihail Ionescu ◽  
Daniel Oldfield ◽  
Joel Davis ◽  
...  
Keyword(s):  
Storage Conditions ◽  
Sample Volume ◽  
X Ray Diffraction ◽  
Pristine Sample ◽  
Waste Storage ◽  
Full Analysis ◽  
Diffraction Patterns ◽  
Displacement Per Atom ◽  
Insight Into

We have examined the irradiation response of a titanate and zirconate pyrochlore—both of which are well studied in the literature individually—in an attempt to define the appearance of defect fluorite in zirconate pyrochlores. To our knowledge this study is unique in that it attempts to discover the mechanism of formation by a comparison of the different systems exposed to the same conditions and then examined via a range of techniques that cover a wide length scale. The conditions of approximately 1 displacement per atom via He2+ ions were used to simulate long term waste storage conditions as outlined by previous results from Ewing in a large enough sample volume to allow for neutron diffraction, as not attempted previously. The titanate sample, used as a baseline comparison since it readily becomes amorphous under these conditions behaved as expected. In contrast, the zirconate sample accumulates tensile stress in the absence of detectable strain. We propose this is analogous to the lanthanide zirconate pyrochlores examined by Simeone et al. where they reported the appearance of defect fluorite diffraction patterns due to a reduction in grain size. Radiation damage and stress results in the grains breaking into even smaller crystallites, thus creating even smaller coherent diffraction domains. An (ErNd)2(ZrTi)2O7 pyrochlore was synthesized to examine which mechanism might dominate, amorphization or stress/strain build up. Although strain was detected in the pristine sample via Synchrotron X-ray diffraction it was not of sufficient quality to perform a full analysis on.

Structural and electrochemical properties of Ti–Ru–Fe–O alloys prepared by high energy ball-milling

1998 ◽  
Vol 13 (5) ◽  
pp. 1171-1176 ◽  
Author(s):  
S-H. Yip ◽  
D. Guay ◽  
S. Jin ◽  
E. Ghali ◽  
A. Van Neste ◽  
...  
Keyword(s):  
Electrochemical Properties ◽  
High Energy ◽  
X Ray Diffraction ◽  
Long Term Stability ◽  
Ternary Metal ◽  
Oxide Phases ◽  
Energy Ball ◽  
Diffraction Patterns ◽  
B2 Structure

The structural and electrochemical properties of the Ti–Ru–Fe–O system have been studied over the whole ternary metal compositional range, keeping constant the oxygen content at 30 at.%. The phase diagram was explored systematically by varying the composition of the material along one of the following axes: (i) constant Ru content of 16 at. %; (ii) constant Ti/Ru ratio of 2; (iii) constant Ti/Fe ratio of 1.6. For O/Ti ratios equal or below unity, the most prominent peaks observed in the x-ray diffraction patterns belong to a B2 structure. For O/Ti ratio larger than unity, stable titanium oxide phases are formed, which coexist with a cubic Fe-like or hcp-Ru like phases depending on the Fe/Ru ratio. Powder compositions with stoichiometry close to Ti2RuFeO2 are of interest due to good electrocatalytic properties, long-term stability, and low Ru content.

scholarly journals Versatile electrochemical cell for Li/Na-ion batteries and high-throughput setup for combinedoperandoX-ray diffraction and absorption spectroscopy

2016 ◽  
Vol 49 (6) ◽  
pp. 1972-1981 ◽  
Author(s):  
Jonas Sottmann ◽  
Roberto Homs-Regojo ◽  
David S. Wragg ◽  
Helmer Fjellvåg ◽  
Serena Margadonna ◽  
...  
Keyword(s):  
Electrode Materials ◽  
Electrochemical Cell ◽  
High Capacity ◽  
Electrochemical Cells ◽  
X Ray Diffraction ◽  
Composition Profiles ◽  
Multi Phase ◽  
Insight Into ◽  
Aqueous Batteries

A fundamental understanding of de/intercalation processes (single phaseversusmulti-phase), structural stability and voltage–composition profiles is pivotal for optimization of electrode materials for rechargeable non-aqueous batteries. A fully operational setup (electrochemical cells, sample changer and interfacing software) that enables combined quasi-simultaneousoperandoX-ray diffraction (XRD) and absorption (XANES and EXAFS) measurements coupled with electrochemical characterization is presented. Combined XRD, XANES and EXAFS analysis provides a deep insight into the working mechanisms of electrode materials, as shown for the high-voltage Li insertion cathode material LiMn1.5Ni0.5O4and the high-capacity sodium conversion anode material Bi2S3. It is also demonstrated that the cell design can be used for in-house XRD characterization. Long-term cycling experiments on both Li and Na electrode materials prove the hermeticity and chemical stability of the design as a versatileoperandoelectrochemical cell.

A new insight into polyurethane foam deterioration - the use of Raman microscopy for the evaluation of long-term storage conditions

2016 ◽  
Vol 47 (12) ◽  
pp. 1494-1504 ◽  
Author(s):  
Susana França de Sá ◽  
Joana Lia Ferreira ◽  
Ana Sofia Matos ◽  
Rita Macedo ◽  
Ana Maria Ramos
Keyword(s):  
Polyurethane Foam ◽  
Storage Conditions ◽  
Raman Microscopy ◽  
Long Term Storage ◽  
Term Storage ◽  
Insight Into

scholarly journals Charge Order and Suppression of Superconductivity in HgBa2CuO4+d at High Pressures

2021 ◽  
Vol 6 (3) ◽  
pp. 25
Author(s):  
Manuel Izquierdo ◽  
Daniele C. Freitas ◽  
Dorothée Colson ◽  
Gastón Garbarino ◽  
Anne Forget ◽  
...  
Keyword(s):  
High Pressures ◽  
Charge Order ◽  
Charge Ordering ◽  
X Ray Diffraction ◽  
Metallic Behavior ◽  
X Ray ◽  
Resistivity Measurements ◽  
Diffraction Patterns ◽  
A Charge ◽  
Insight Into

New insight into the superconducting properties of HgBa2CuO4 (Hg-1201) cuprates is provided by combined measurements of electrical resistivity and single crystal X-ray diffraction under pressure. The changes induced by increasing pressure up to 20 GPa in optimally doped single crystals were investigated. The resistivity measurements as a function of temperature show a metallic behavior up to ~10 GPa that gradually passes into an insulating state, typical of charge ordering, which totally suppresses superconductivity above 13 GPa. The changes in resistivity are accompanied by the apparition of sharp Bragg peaks in the X-ray diffraction patterns, indicating that the charge ordering is accompanied by a 3D oxygen ordering. Considering that pressure induces a charge transfer of about 0.02 at 10 GPa, our results are the first observation of charge order competing with superconductivity developed in the overdoped region of the phase diagram of a Hg-based cuprate.

scholarly journals Charge State of Silver Halide Colloids Determines the Antibacterial Activity in Amorphous Calcium Phosphate

2013 ◽  
Vol 587 ◽  
pp. 74-79 ◽  
Author(s):  
Kārlis Gross ◽  
Daina Kalnina ◽  
Zivile Stankeviciute ◽  
Vizma Nikolajeva
Keyword(s):  
Calcium Phosphate ◽  
Amorphous Calcium Phosphate ◽  
Silver Iodide ◽  
Calcium Phosphates ◽  
Silver Halide ◽  
Antibacterial Action ◽  
X Ray Diffraction ◽  
Silver Halides ◽  
Diffraction Patterns

Removal of bacteria is important not only at implantation, but after long-term implant/prosthesis use. This requires strategies that employ different approaches for combating bacteria. Halides have the potential of an additional mechanism, and together with silver may provide a more powerful antibacterial strategy. Silver iodide was synthesized as colloids with a positive and negative charge and incorporated into an amorphous calcium phosphate (ACP) to provide a possible greater antibacterial action. Colloids were characterized by FTIR spectroscopy and the charge measured by zeta potential. Phase analysis by X-ray diffraction patterns confirmed the formation of b-AgI nanoparticles. Minimum inhibitory concentrations (MIC) for preventing the growth ofStaphylococcus aureusandPseudomonas aeruginosawere lower for ACP containing negatively charged silver halides. Amorphous calcium phosphates with silver iodide exhibited good inhibition capacity. Solubility was determined by the increase in pH and the release of silver after 48 hours. The minimum bactericidal concentration (MBC) was also determined. This work has shown the effect of AgI charge in amorphous calcium phosphate for providing antibacterial action.

Evaluation of Freezing Methods by Low Temperature X-Ray Diffraction

1977 ◽  
Vol 35 ◽  
pp. 330-333
Author(s):  
T. Gulik-Krzywicki ◽  
M.J. Costello
Keyword(s):  
Biological Materials ◽  
Molecular Organization ◽  
X Ray Diffraction ◽  
Glass Capillary ◽  
X Ray ◽  
Rate Dependent ◽  
Before And After ◽  
Freeze Etching ◽  
Diffraction Patterns ◽  
Set Up

Freeze-etching electron microscopy is currently one of the best methods for studying molecular organization of biological materials. Its application, however, is still limited by our imprecise knowledge about the perturbations of the original organization which may occur during quenching and fracturing of the samples and during the replication of fractured surfaces. Although it is well known that the preservation of the molecular organization of biological materials is critically dependent on the rate of freezing of the samples, little information is presently available concerning the nature and the extent of freezing-rate dependent perturbations of the original organizations. In order to obtain this information, we have developed a method based on the comparison of x-ray diffraction patterns of samples before and after freezing, prior to fracturing and replication.Our experimental set-up is shown in Fig. 1. The sample to be quenched is placed on its holder which is then mounted on a small metal holder (O) fixed on a glass capillary (p), whose position is controlled by a micromanipulator.

Examination of Rabbit Fc Crystals

1968 ◽  
Vol 26 ◽  
pp. 140-141
Author(s):  
J. P. Robinson ◽  
P. G. Lenhert
Keyword(s):  
Molecular Weight ◽  
Flat Plate ◽  
Phosphate Buffer ◽  
Asymmetric Unit ◽  
X Ray Diffraction ◽  
X Ray ◽  
Neutral Ph ◽  
Small Crystals ◽  
Carbon Coated ◽  
Diffraction Patterns

Crystallographic studies of rabbit Fc using X-ray diffraction patterns were recently reported. The unit cell constants were reported to be a = 69. 2 A°, b = 73. 1 A°, c = 60. 6 A°, B = 104° 30', space group P21, monoclinic, volume of asymmetric unit V = 148, 000 A°3. The molecular weight of the fragment was determined to be 55, 000 ± 2000 which is in agreement with earlier determinations by other methods.Fc crystals were formed in water or dilute phosphate buffer at neutral pH. The resulting crystal was a flat plate as previously described. Preparations of small crystals were negatively stained by mixing the suspension with equal volumes of 2% silicotungstate at neutral pH. A drop of the mixture was placed on a carbon coated grid and allowed to stand for a few minutes. The excess liquid was removed and the grid was immediately put in the microscope.

Quantitative Electron Microscope with imaging plate

1994 ◽  
Vol 52 ◽  
pp. 408-409
Author(s):  
D. Shindo
Keyword(s):  
Electron Microscope ◽  
Dynamic Range ◽  
Processing System ◽  
Digital Data ◽  
Imaging Plate ◽  
Crystal Thickness ◽  
X Ray Diffraction ◽  
Resolution Electron ◽  
Electron Intensity ◽  
Diffraction Patterns

Imaging plate has good properties, i.e., a wide dynamic range and good linearity for the electron intensity. Thus the digital data (2048x1536 pixels, 4096 gray levels in log scale) obtained with the imaging plate can be used for quantification in electron microscopy. By using the image processing system (PIXsysTEM) combined with a main frame (ACOS3900), quantitative analysis of electron diffraction patterns and high-resolution electron microscope (HREM) images has been successfully carried out.In the analysis of HREM images observed with the imaging plate, quantitative comparison between observed intensity and calculated intensity can be carried out by taking into account the experimental parameters such as crystal thickness and defocus value. An example of HREM images of quenched Tl2Ba2Cu1Oy (Tc = 70K) observed with the imaging plate is shown in Figs. 1(b) - (d) comparing with a structure model proposed by x-ray diffraction study of Fig. 1 (a). The image was observed with a JEM-4000EX electron microscope (Cs =1.0 mm).

Turkish Muslims in a German city: Entrepreneurial and residential self-determination

2015 ◽  
Vol 12 (1) ◽  
pp. 1-12
Author(s):  
Sarah Hackett
Keyword(s):  
Residential Patterns ◽  
Academic Literature ◽  
Self Employment ◽  
German City ◽  
Post War ◽  
Oral History Interviews ◽  
The City ◽  
Insight Into ◽  
Term Objective

Drawing upon a collection of oral history interviews, this paper offers an insight into entrepreneurial and residential patterns and behaviour amongst Turkish Muslims in the German city of Bremen. The academic literature has traditionally argued that Turkish migrants in Germany have been pushed into self-employment, low-quality housing and segregated neighbourhoods as a result of discrimination, and poor employment and housing opportunities. Yet the interviews reveal the extent to which Bremen’s Turkish Muslims’ performances and experiences have overwhelmingly been the consequences of personal choices and ambitions. For many of the city’s Turkish Muslim entrepreneurs, self-employment had been a long-term objective, and they have succeeded in establishing and running their businesses in the manner they choose with regards to location and clientele, for example. Similarly, interviewees stressed the way in which they were able to shape their housing experiences by opting which districts of the city to live in and by purchasing property. On the whole, they perceive their entrepreneurial and residential practices as both consequences and mediums of success, integration and a loyalty to the city of Bremen. The findings are contextualised within the wider debate regarding the long-term legacy of Germany’s post-war guest-worker system and its position as a “country of immigration”.

Control of the phase composition of advanced calcium phosphates using an x-ray diffractometer with a curved position-sensitive detector

2020 ◽  
Vol 86 (6) ◽  
pp. 29-35
Author(s):  
V. P. Sirotinkin ◽  
O. V. Baranov ◽  
A. Yu. Fedotov ◽  
S. M. Barinov
Keyword(s):  
Phase Composition ◽  
Calcium Phosphates ◽  
Position Sensitive Detector ◽  
Sensitive Detector ◽  
X Ray Diffraction ◽  
X Ray ◽  
Impurity Phases ◽  
Position Sensitive ◽  
Diffraction Peaks ◽  
Diffraction Patterns

The results of studying the phase composition of advanced calcium phosphates Ca10(PO4)6(OH)2, β-Ca3(PO4)2, α-Ca3(PO4)2, CaHPO4 · 2H2O, Ca8(HPO4)2(PO4)4 · 5H2O using an x-ray diffractometer with a curved position-sensitive detector are presented. Optimal experimental conditions (angular positions of the x-ray tube and detector, size of the slits, exposure time) were determined with allowance for possible formation of the impurity phases during synthesis. The construction features of diffractometers with a position-sensitive detector affecting the profile characteristics of x-ray diffraction peaks are considered. The composition for calibration of the diffractometer (a mixture of sodium acetate and yttrium oxide) was determined. Theoretical x-ray diffraction patterns for corresponding calcium phosphates are constructed on the basis of the literature data. These x-ray diffraction patterns were used to determine the phase composition of the advanced calcium phosphates. The features of advanced calcium phosphates, which should be taken into account during the phase analysis, are indicated. The powder of high-temperature form of tricalcium phosphate strongly adsorbs water from the environment. A strong texture is observed on the x-ray diffraction spectra of dicalcium phosphate dihydrate. A rather specific x-ray diffraction pattern of octacalcium phosphate pentahydrate revealed the only one strong peak at small angles. In all cases, significant deviations are observed for the recorded angular positions and relative intensity of the diffraction peaks. The results of the study of experimentally obtained mixtures of calcium phosphate are presented. It is shown that the graphic comparison of experimental x-ray diffraction spectra and pre-recorded spectra of the reference calcium phosphates and possible impurity phases is the most effective method. In this case, there is no need for calibration. When using this method, the total time for analysis of one sample is no more than 10 min.

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