Oxygen Transport in the Sr2Fe3−x, CoxOy System

1998 ◽  
Vol 548 ◽  
Author(s):  
B. Ma ◽  
U. Balachandran ◽  
B.J. Mitchell ◽  
J.W. Richardson ◽  
J.P. Hodges ◽  
...  
Keyword(s):  
Oxygen Transport ◽  
Large Scale ◽  
Transient Behavior ◽  
Weight Changes ◽  
X Ray Diffraction ◽  
X Ray ◽  
Gas Separation Membrane ◽  
Separation Membrane ◽  
Oxide Membranes ◽  
Potential Use

ABSTRACTThe mixed-conducting Sr-Fe-Co oxide has potential use as a gas separation membrane. Its superior oxygen transport reveals the feasibility of using oxide membranes in large-scale oxygen separation. Sr2Fe3-xCoxOy (with x = 0.0, 0.3, 0.6, and 1.0) samples were made by solid state reaction. To understand the oxygen transport mechanism in this system, conductivity and thermogravimetry experiments were conducted at high temperature in various oxygen partial pressure environments. The oxygen diffusion coefficient was determined from the time relaxation transient behavior of the specimen after switching the surrounding atmosphere. Mobility of the charge carrier was derived from relative conductivity and weight changes. X-ray diffraction experiments were carried out on these samples to determine their crystal structures.

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

2013 ◽  
Vol 772 ◽  
pp. 193-199 ◽  
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.

Template Synthesis of Indium Nanowires Using Anodic Aluminum Oxide Membranes

2008 ◽  
Vol 8 (9) ◽  
pp. 4488-4493 ◽  
Author(s):  
Feng Chen ◽  
Adrian H. Kitai
Keyword(s):  
Aluminum Oxide ◽  
Template Synthesis ◽  
Anodic Aluminum Oxide ◽  
Preferred Orientation ◽  
Hydraulic Pressure ◽  
X Ray Diffraction ◽  
Aao Template ◽  
X Ray ◽  
Anodic Aluminum ◽  
Oxide Membranes

Indium nanowires with diameters approximately 300 nm have been synthesized by a hydraulic pressure technique using anodic aluminum oxide (AAO) templates. The indium melt is injected into the AAO template and solidified to form nanostructures. The nanowires are dense, continuous and uniformly run through the entire ∼60 μm thickness of the AAO template. X-ray diffraction (XRD) reveals that the nanowires are polycrystalline with a preferred orientation. SEM is performed to characterize the morphology of the nanowires.

The Croonian Lecture, 1970 The structural basis of muscular contraction

1971 ◽  
Vol 178 (1051) ◽  
pp. 131-149 ◽  
Keyword(s):  
Large Scale ◽  
Muscular Contraction ◽  
Important Change ◽  
Structural Basis ◽  
X Ray Diffraction ◽  
New Era ◽  
X Ray ◽  
Biology I ◽  
The Times ◽  
Polypeptide Chains

A previous occasion on which the Croonian lecture was directly concerned with the mechanism of muscular contraction was in 1945, when it was delivered by Professor W. T. Astbury. On that occasion he commented that it was a sign of the times that a physicist should be asked to give the Croonian lecture, and went on to say, and I quote: ‘We are at the dawn of a new era, the era of “molecular biology”, as I like to call it, and there is an urgency about the need for more intensive application of physics and chemistry, and specially structural analysis, to biological problems.’ These were very prophetic words, and, as a physicist just entering biology, I was much interested to read them, and to learn about his experiments. The basic experimental finding which Astbury reported (1947) was that there did not seem to be any important change in the wide angle X-ray diagram from muscle upon contraction; hence it followed that muscles did not contract by any process which simply involved the large-scale disorientation of originally well-ordered polypeptide chains, nor by an alteration in chain configuration in the well-ordered parts of the structure. Astbury suggested instead that there might be ‘specifically active foci’ which one could perhaps paraphrase as ‘larger structural units’ (i.e. larger than individual polypeptide chains) concerned in contraction, which might be studied in the electron microscope or by low angle X-ray diffraction.

In-Situ Diffraction Studies of Gas Storage Materials on a Laboratory X-Ray System

2013 ◽  
Vol 1544 ◽  
Author(s):  
Marco Sommariva ◽  
Harald van Weeren ◽  
Olga Narygina ◽  
Jan-André Gertenbach ◽  
Christian Resch ◽  
...  
Keyword(s):  
Large Scale ◽  
Fossil Fuels ◽  
Reaction Chamber ◽  
Hydrogen Gas ◽  
Gas Pressure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structural Modifications ◽  
Model Studies

ABSTRACTThe sorption processes for hydrogen and carbon dioxide are of considerable, and growing interest, particularly due to their relevance to a society that seeks to replace fossil fuels with a more sustainable energy source. X-ray diffraction allows a unique perspective for studying structural modifications and reaction mechanisms that occur when gas and solid interact. The fundamental challenge associated with such a study is that experiments are conducted while the solid sample is held under a gas pressure. To date in-situ high gas pressure studies of this nature have typically been undertaken at large-scale facilities such as synchrotrons or on dedicated laboratory instruments. Here we report high-pressure XRD studies carried out on a multi-purpose diffractometer. To demonstrate the suitability of the equipment, two model studies were carried out, firstly the reversible hydrogen cycling over LaNi5, and secondly the structural change that occurs during the decomposition of ammonia borane that results in the generation of hydrogen gas in the reaction chamber. The results have been finally compared to the literature. The study has been made possible by the combination of rapid X-ray detectors with a reaction chamber capable of withstanding gas pressures up to 100 bar and temperatures up to 900 °C.

scholarly journals Study of Chemical and Morphological Transformations during Ni2Mo3N Synthesis via an Oxide Precursor Nitration Route

Catalysts ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 436
Author(s):  
Denis Leybo ◽  
Dmitry Arkhipov ◽  
Konstantin Firestein ◽  
Denis Kuznetsov
Keyword(s):  
Weight Changes ◽  
X Ray Diffraction ◽  
X Ray ◽  
Oxide Precursor ◽  
Nitride Formation ◽  
Extended Surface ◽  
Temperature Programmed ◽  
Morphological Transformations ◽  
Physical And Chemical ◽  
Oxide Sample

Chemical and morphological transformations during Ni2Mo3N synthesis were studied in this work. Nitride samples were synthesized from oxide precursors in H2/N2 flow and were analyzed by thermogravimetry, X-ray diffraction analysis, scanning electron microscopy, and energy dispersive X-ray spectroscopy methods. In addition, physical and chemical adsorption properties were studied using low-temperature N2 physisorption and NH3 temperature-programmed desorption. It was shown that nitride formation proceeds through a sequence of phase transformations: NiMoO4 + MoO3 → Ni + NiMo + MoO2 → Ni + NiMo + Mo2N → Ni2Mo3N. The weight changes that were calculated from the proposed reactions were in agreement with the experimental data from thermogravimetry. The morphology of the powder changed from platelets and spheres for the oxide sample, to aggregates of needle-like particles for the intermediate product, to porous particles with an extended surface area for the nitride final product. The obtained results should prove useful for subsequent Ni2Mo3N based catalysts production process optimization.

Bioactive comparison of a borate, phosphate and silicate glass

2006 ◽  
Vol 21 (1) ◽  
pp. 125-131 ◽  
Author(s):  
Wen Liang ◽  
Christian Rüssel ◽  
Delbert E. Day ◽  
Günter Völksch
Keyword(s):  
Silicate Glass ◽  
Phosphate Glass ◽  
Ph Value ◽  
Phosphate Glasses ◽  
Tissue Formation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Reaction Processes ◽  
Bone Tissue Formation ◽  
Potential Use

A borate glass, phosphate glass, and silicate glass were converted to hydroxyapatite (HA) by soaking the substrates in a solution of K2HPO4 with a pH value of 9.0 at 37 °C. The weight loss of the substrates was studied as a function of time. Unlike the silicate glasses, the reaction processes of the borate glasses and phosphate glasses were bulk dissolution. X-ray diffraction and scanning electron microscopy revealed an initially amorphous product that subsequently crystallized to HA. The data suggest good bioactive characteristics for the borate and phosphate glass and the potential use of them as a favorable template for bone-tissue formation.

Large-scale and facile fabrication of PbSe nanostructures by selenization of a Pb sheet

2015 ◽  
Vol 08 (05) ◽  
pp. 1550063 ◽  
Author(s):  
Sara Hoomi ◽  
Ramin Yousefi ◽  
Farid Jamali-Sheini ◽  
Abdolhossein Sáaedi ◽  
Mohsen Cheraghizade ◽  
...  
Keyword(s):  
Large Scale ◽  
Chemical Vapor ◽  
Infrared Region ◽  
Photoelectron Spectra ◽  
X Ray Diffraction ◽  
X Ray ◽  
Facile Fabrication ◽  
Higher Temperature ◽  
Set Up ◽  
Lower Temperature

PbSe nanostructures were synthesized by selenization of lead sheets in a chemical vapor deposition (CVD) set-up under a selenium ambiance. The lead sheets were placed in the different temperature zones, between 300°C and 450°C. Field emission scanning electron microscope (FESEM) images showed that, PbSe nanostructures grown on the lead sheets with different morphologies. PbSe nanostructures with flakes shape were grown on the lead sheets that were placed in the lower temperature, while PbSe nanocubes and nanorods, which were grown on the nanocubes, were grown on the lead sheets in the higher temperature. The phase and composition of the product were identified by X-ray diffraction (XRD) pattern and X-ray photoelectron spectra (XPS). The XRD and XPS results showed that, the PbSe phase was started to form after 350°C and completed at 450°C. However, the XPS results showed that the Se concentration was different in the samples. In addition, Raman measurements confirmed the XRD and XPS results and indicated three Raman active modes, which belonged to PbSe phase for the nanostructures. The optical properties of the products were characterized by UV–Vis. The optical characterization results showed a band gap for the PbSe nanostructures in the infrared region.

scholarly journals In Situ Observation of Stress Accumulation during Sub-Merged Arc Welding

2014 ◽  
Vol 996 ◽  
pp. 417-423 ◽  
Author(s):  
Arne Kromm ◽  
Thomas Kannengiesser
Keyword(s):  
Arc Welding ◽  
Large Scale ◽  
X Ray Diffraction ◽  
X Ray ◽  
Residual Stress State ◽  
Testing Facility ◽  
Large Scale Testing ◽  
The Impact ◽  
Stress Accumulation

Results obtained from laboratory tests mostly need to be verified under fabrication conditions in order to incorporate design specifics (joint configuration and restraint), which effect the residual stress state considerably. For this purpose, multi-pass sub merged arc welding was performed in a special large-scale testing facility. The impact of varying interpass temperatures could be proven in-situ by means of a pronounced stress accumulation during welding and subsequent heat treatment accompanied by stress determination using X-ray diffraction.

Variables Involved in the Planting of Rice in the Rice Husk

2012 ◽  
Vol 517 ◽  
pp. 430-436
Author(s):  
J.L. Akasaki ◽  
E.J. Silva ◽  
L.C. Sousa ◽  
J.L.P. Melges ◽  
M.M. Tashima ◽  
...  
Keyword(s):  
Rice Husk ◽  
Large Scale ◽  
Rice Husk Ash ◽  
Scale Production ◽  
X Ray Diffraction ◽  
X Ray ◽  
Large Scale Production ◽  
Pozzolanic Materials ◽  
Different Strains ◽  
Different Origins

Rice production in Brazil in 2010 was approximately 12,2 million tons, and to reach that amount several planting techniques were used with different strains of rice in different rice-growing areas. Since Rice Husk Ash (RHA) is the pozzolan of vegetable origin most studied by researchers working in the area of pozzolanic materials, the present paper evaluates the influence that the form of planting, the climate, the soil, the strain of rice and the origin/amount of nitrogen-based fertilizers used in rice cultivation has on the chemical composition and crystallographic properties of RHA. The results obtained in this paper, confirm the importance of carrying out routine chemical analysis and X-Ray diffraction to maintain the quality control of the CCAs produced, because in situations of large-scale production, husks of different origins may be used.

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