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Sample records for powder diffraction method

  1. Powder diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Hart, M.

    1995-12-31

    the importance of x-ray powder diffraction as an analytical tool for phase identification of materials was first pointed out by Debye and Scherrer in Germany and, quite independently, by Hull in the US. Three distinct periods of evolution lead to ubiquitous application in many fields of science and technology. In the first period, until the mid-1940`s, applications were and developed covering broad categories of materials including inorganic materials, minerals, ceramics, metals, alloys, organic materials and polymers. During this formative period, the concept of quantitative phase analysis was demonstrated. In the second period there followed the blossoming of technology and commercial instruments became widely used. The history is well summarized by Parrish and by Langford and Loueer. By 1980 there were probably 10,000 powder diffractometers in routine use, making it the most widely used of all x-ray crystallographic instruments. In the third, present, period data bases became firmly established and sophisticated pattern fitting and recognition software made many aspects of powder diffraction analysis routine. High resolution, tunable powder diffractometers were developed at sources of synchrotron radiation. The tunability of the spectrum made it possible to exploit all the subtleties of x-ray spectroscopy in diffraction experiments.

  2. Powder diffraction

    International Nuclear Information System (INIS)

    Hart, M.

    1995-01-01

    The importance of x-ray powder diffraction as an analytical tool for phase identification of materials was first pointed out by Debye and Scherrer in Germany and, quite independently, by Hull in the US. Three distinct periods of evolution lead to ubiquitous application in many fields of science and technology. In the first period, until the mid-1940's, applications were and developed covering broad categories of materials including inorganic materials, minerals, ceramics, metals, alloys, organic materials and polymers. During this formative period, the concept of quantitative phase analysis was demonstrated. In the second period there followed the blossoming of technology and commercial instruments became widely used. The history is well summarized by Parrish and by Langford and Loueer. By 1980 there were probably 10,000 powder diffractometers in routine use, making it the most widely used of all x-ray crystallographic instruments. In the third, present, period data bases became firmly established and sophisticated pattern fitting and recognition software made many aspects of powder diffraction analysis routine. High resolution, tunable powder diffractometers were developed at sources of synchrotron radiation. The tunability of the spectrum made it possible to exploit all the subtleties of x-ray spectroscopy in diffraction experiments

  3. Comparison between powder and slices diffraction methods in teeth samples

    Energy Technology Data Exchange (ETDEWEB)

    Colaco, Marcos V.; Barroso, Regina C. [Universidade do Estado do Rio de Janeiro (IF/UERJ), RJ (Brazil). Inst. de Fisica. Dept. de Fisica Aplicada; Porto, Isabel M. [Universidade Estadual de Campinas (FOP/UNICAMP), Piracicaba, SP (Brazil). Fac. de Odontologia. Dept. de Morfologia; Gerlach, Raquel F. [Universidade de Sao Paulo (FORP/USP), Rieirao Preto, SP (Brazil). Fac. de Odontologia. Dept. de Morfologia, Estomatologia e Fisiologia; Costa, Fanny N. [Coordenacao dos Programas de Pos-Graduacao de Engenharia (LIN/COPPE/UFRJ), RJ (Brazil). Lab. de Instrumentacao Nuclear

    2011-07-01

    Propose different methods to obtain crystallographic information about biological materials are important since powder method is a nondestructive method. Slices are an approximation of what would be an in vivo analysis. Effects of samples preparation cause differences in scattering profiles compared with powder method. The main inorganic component of bones and teeth is a calcium phosphate mineral whose structure closely resembles hydroxyapatite (HAp). The hexagonal symmetry, however, seems to work well with the powder diffraction data, and the crystal structure of HAp is usually described in space group P63/m. Were analyzed ten third molar teeth. Five teeth were separated in enamel, detin and circumpulpal detin powder and five in slices. All the scattering profile measurements were carried out at the X-ray diffraction beamline (XRD1) at the National Synchrotron Light Laboratory - LNLS, Campinas, Brazil. The LNLS synchrotron light source is composed of a 1.37 GeV electron storage ring, delivering approximately 4x10{sup -1}0 photons/s at 8 keV. A double-crystal Si(111) pre-monochromator, upstream of the beamline, was used to select a small energy bandwidth at 11 keV . Scattering signatures were obtained at intervals of 0.04 deg for angles from 24 deg to 52 deg. The human enamel experimental crystallite size obtained in this work were 30(3)nm (112 reflection) and 30(3)nm (300 reflection). These values were obtained from measurements of powdered enamel. When comparing the slice obtained 58(8)nm (112 reflection) and 37(7)nm (300 reflection) enamel diffraction patterns with those generated by the powder specimens, a few differences emerge. This work shows differences between powder and slices methods, separating characteristics of sample of the method's influence. (author)

  4. Comparison between powder and slices diffraction methods in teeth samples

    International Nuclear Information System (INIS)

    Colaco, Marcos V.; Barroso, Regina C.; Porto, Isabel M.; Gerlach, Raquel F.; Costa, Fanny N.

    2011-01-01

    Propose different methods to obtain crystallographic information about biological materials are important since powder method is a nondestructive method. Slices are an approximation of what would be an in vivo analysis. Effects of samples preparation cause differences in scattering profiles compared with powder method. The main inorganic component of bones and teeth is a calcium phosphate mineral whose structure closely resembles hydroxyapatite (HAp). The hexagonal symmetry, however, seems to work well with the powder diffraction data, and the crystal structure of HAp is usually described in space group P63/m. Were analyzed ten third molar teeth. Five teeth were separated in enamel, detin and circumpulpal detin powder and five in slices. All the scattering profile measurements were carried out at the X-ray diffraction beamline (XRD1) at the National Synchrotron Light Laboratory - LNLS, Campinas, Brazil. The LNLS synchrotron light source is composed of a 1.37 GeV electron storage ring, delivering approximately 4x10 -1 0 photons/s at 8 keV. A double-crystal Si(111) pre-monochromator, upstream of the beamline, was used to select a small energy bandwidth at 11 keV . Scattering signatures were obtained at intervals of 0.04 deg for angles from 24 deg to 52 deg. The human enamel experimental crystallite size obtained in this work were 30(3)nm (112 reflection) and 30(3)nm (300 reflection). These values were obtained from measurements of powdered enamel. When comparing the slice obtained 58(8)nm (112 reflection) and 37(7)nm (300 reflection) enamel diffraction patterns with those generated by the powder specimens, a few differences emerge. This work shows differences between powder and slices methods, separating characteristics of sample of the method's influence. (author)

  5. The analysis of powder diffraction data

    International Nuclear Information System (INIS)

    David, W.I.F.; Harrison, W.T.A.

    1986-01-01

    The paper reviews neutron powder diffraction data analysis, with emphasis on the structural aspects of powder diffraction and the future possibilities afforded by the latest generation of very high resolution neutron and x-ray powder diffractometers. Traditional x-ray powder diffraction techniques are outlined. Structural studies by powder diffraction are discussed with respect to the Rietveld method, and a case study in the Rietveld refinement method and developments of the Rietveld method are described. Finally studies using high resolution powder diffraction at the Spallation Neutron Source, ISIS at the Rutherford Appleton Laboratory are summarized. (U.K.)

  6. Diffraction. Powder, amorphous, liquid

    International Nuclear Information System (INIS)

    Sosnowska, I.M.

    1999-01-01

    Neutron powder diffraction is a unique tool to observe all possible diffraction effects appearing in crystal. High-resolution neutron diffractometers have to be used in this study. Analysis of the magnetic structure of polycrystalline materials requires the use of high-resolution neutron diffraction in the range of large interplanar distances. As distinguished from the double axis diffractometers (DAS), which show high resolution only at small interplanar distances, TOF (time-of-flight) diffractometry offers the best resolution at large interplanar distances. (K.A.)

  7. Rietveld analysis using powder diffraction data with anomalous scattering effect obtained by focused beam flat sample method

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Masahiko, E-mail: masahiko@spring8.or.jp; Katsuya, Yoshio, E-mail: katsuya@spring8.or.jp; Sakata, Osami, E-mail: SAKATA.Osami@nims.go.jp [Synchrotron X-ray Station at SPring-8, National Institute for Materials Science 1-1-1 Kouto, Sayo, Hyogo 679-5198 (Japan)

    2016-07-27

    Focused-beam flat-sample method (FFM) is a new trial for synchrotron powder diffraction method, which is a combination of beam focusing optics, flat shape powder sample and area detectors. The method has advantages for X-ray diffraction experiments applying anomalous scattering effect (anomalous diffraction), because of 1. Absorption correction without approximation, 2. High intensity X-rays of focused incident beams and high signal noise ratio of diffracted X-rays 3. Rapid data collection with area detectors. We applied the FFM to anomalous diffraction experiments and collected synchrotron X-ray powder diffraction data of CoFe{sub 2}O{sub 4} (inverse spinel structure) using X-rays near Fe K absorption edge, which can distinguish Co and Fe by anomalous scattering effect. We conducted Rietveld analyses with the obtained powder diffraction data and successfully determined the distribution of Co and Fe ions in CoFe{sub 2}O{sub 4} crystal structure.

  8. Rietveld analysis using powder diffraction data with anomalous scattering effect obtained by focused beam flat sample method

    International Nuclear Information System (INIS)

    Tanaka, Masahiko; Katsuya, Yoshio; Sakata, Osami

    2016-01-01

    Focused-beam flat-sample method (FFM) is a new trial for synchrotron powder diffraction method, which is a combination of beam focusing optics, flat shape powder sample and area detectors. The method has advantages for X-ray diffraction experiments applying anomalous scattering effect (anomalous diffraction), because of 1. Absorption correction without approximation, 2. High intensity X-rays of focused incident beams and high signal noise ratio of diffracted X-rays 3. Rapid data collection with area detectors. We applied the FFM to anomalous diffraction experiments and collected synchrotron X-ray powder diffraction data of CoFe_2O_4 (inverse spinel structure) using X-rays near Fe K absorption edge, which can distinguish Co and Fe by anomalous scattering effect. We conducted Rietveld analyses with the obtained powder diffraction data and successfully determined the distribution of Co and Fe ions in CoFe_2O_4 crystal structure.

  9. A standardless method of quantitative ceramic analysis using X-ray powder diffraction

    International Nuclear Information System (INIS)

    Mazumdar, S.

    1999-01-01

    A new procedure using X-ray powder diffraction data for quantitative estimation of the crystalline as well as the amorphous phase in ceramics is described. Classification of the crystalline and amorphous X-ray scattering was achieved by comparison of the slopes at two successive points of the powder pattern at scattering angles at which the crystalline and amorphous phases superimpose. If the second slope exceeds the first by a stipulated value, the intensity is taken as crystalline; otherwise the scattering is considered as amorphous. Crystalline phase analysis is obtained by linear programming techniques using the concept that each observed X-ray diffraction peak has contributions from n component phases, the proportionate analysis of which is required. The method does not require the measurement of calibration data for use as an internal standard, but knowledge of the approximate crystal structure of each phase of interest in the mixture is necessary. The technique is also helpful in qualitative analysis because each suspected phase is characterized by the probability that it will be present when a reflection zone is considered in which the suspected crystalline phase could contribute. The amorphous phases are determined prior to the crystalline ones. The method is applied to ceramic materials and some results are presented. (orig.)

  10. Development of powder diffraction anomalous fine structure method and applications to electrode materials for rechargeable batteries

    International Nuclear Information System (INIS)

    Kawaguchi, Tomoya; Fukuda, Katsutoshi; Oishi, Masatsugu; Ichitsubo, Tetsu; Matsubara, Eiichiro; Mizuki, Jun'ichiro

    2015-01-01

    A powder diffraction anomalous fine structure (P-DAFS) method is developed both in analytical and experimental techniques and applied to cathode materials for lithium ion batteries. The DAFS method, which is an absorption spectroscopic technique through a scattering measurement, enables us to analyze the chemical states and the local structures of a certain element at different sites, thanks to the nature of x-ray diffraction, where the contributions from each site are different at each diffraction. Electrode materials for rechargeable batteries frequently exhibit the interchange between Li and a transition metal, which is known as the cation mixing phenomena. This cation mixing significantly affects the whole electrode properties; therefore, the site-distinguished understanding of the roles of the transition metal is essential for further material design by controlling and positively utilizing this cation mixing phenomenon. However, the developments of the P-DAFS method are required for the applications to the practical materials such as the electrode materials. In the present study, a direct analysis technique to extract the absorption spectrum from the scattering without using the conventional iterative calculations, fast and accurate measurement techniques of the P-DAFS method, and applications to a typical electrode material of Li 1-x Ni 1+x O 2 , which exhibits the significant cation mixing, are described. (author)

  11. Neutron Powder Diffraction in Sweden

    International Nuclear Information System (INIS)

    Tellgren, R.

    1986-01-01

    Neutron powder diffraction in Sweden has developed around the research reactor R2 in Studsvik. The article describes this facility and presents a historical review of research results obtained. It also gives some ideas of plans for future development

  12. Powder X-ray diffraction method for the quantification of cocrystals in the crystallization mixture.

    Science.gov (United States)

    Padrela, Luis; de Azevedo, Edmundo Gomes; Velaga, Sitaram P

    2012-08-01

    The solid state purity of cocrystals critically affects their performance. Thus, it is important to accurately quantify the purity of cocrystals in the final crystallization product. The aim of this study was to develop a powder X-ray diffraction (PXRD) quantification method for investigating the purity of cocrystals. The method developed was employed to study the formation of indomethacin-saccharin (IND-SAC) cocrystals by mechanochemical methods. Pure IND-SAC cocrystals were geometrically mixed with 1:1 w/w mixture of indomethacin/saccharin in various proportions. An accurately measured amount (550 mg) of the mixture was used for the PXRD measurements. The most intense, non-overlapping, characteristic diffraction peak of IND-SAC was used to construct the calibration curve in the range 0-100% (w/w). This calibration model was validated and used to monitor the formation of IND-SAC cocrystals by liquid-assisted grinding (LAG). The IND-SAC cocrystal calibration curve showed excellent linearity (R(2) = 0.9996) over the entire concentration range, displaying limit of detection (LOD) and limit of quantification (LOQ) values of 1.23% (w/w) and 3.74% (w/w), respectively. Validation results showed excellent correlations between actual and predicted concentrations of IND-SAC cocrystals (R(2) = 0.9981). The accuracy and reliability of the PXRD quantification method depend on the methods of sample preparation and handling. The crystallinity of the IND-SAC cocrystals was higher when larger amounts of methanol were used in the LAG method. The PXRD quantification method is suitable and reliable for verifying the purity of cocrystals in the final crystallization product.

  13. Application of focused-beam flat-sample method to synchrotron powder X-ray diffraction with anomalous scattering effect

    International Nuclear Information System (INIS)

    Tanaka, M; Katsuya, Y; Matsushita, Y

    2013-01-01

    The focused-beam flat-sample method (FFM), which is a method for high-resolution and rapid synchrotron X-ray powder diffraction measurements by combination of beam focusing optics, a flat shape sample and an area detector, was applied for diffraction experiments with anomalous scattering effect. The advantages of FFM for anomalous diffraction were absorption correction without approximation, rapid data collection by an area detector and good signal-to-noise ratio data by focusing optics. In the X-ray diffraction experiments of CoFe 2 O 4 and Fe 3 O 4 (By FFM) using X-rays near the Fe K absorption edge, the anomalous scattering effect between Fe/Co or Fe 2+ /Fe 3+ can be clearly detected, due to the change of diffraction intensity. The change of observed diffraction intensity as the incident X-ray energy was consistent with the calculation. The FFM is expected to be a method for anomalous powder diffraction.

  14. Uniting Electron Crystallography and Powder Diffraction

    CERN Document Server

    Shankland, Kenneth; Meshi, Louisa; Avilov, Anatoly; David, William

    2012-01-01

    The polycrystalline and nanocrystalline states play an increasingly important role in exploiting the properties of materials, encompassing applications as diverse as pharmaceuticals, catalysts, solar cells and energy storage. A knowledge of the three-dimensional atomic and molecular structure of materials is essential for understanding and controlling their properties, yet traditional single-crystal X-ray diffraction methods lose their power when only polycrystalline and nanocrystalline samples are available. It is here that powder diffraction and single-crystal electron diffraction techniques take over, substantially extending the range of applicability of the crystallographic principles of structure determination.  This volume, a collection of teaching contributions presented at the Crystallographic Course in Erice in 2011, clearly describes the fundamentals and the state-of-the-art of powder diffraction and electron diffraction methods in materials characterisation, encompassing a diverse range of discipl...

  15. Structural study on the gas adsorption phenomena in porous coordination polymers by synchrotron powder diffraction method

    International Nuclear Information System (INIS)

    Kubota, Yoshiki

    2017-01-01

    In situ synchrotron powder diffraction measurement of gas adsorption and crystal structure analysis for porous coordination polymers (PCPs) were performed. From the obtained accurate crystal structure in both atomic and charge density levels, not only the position and orientation of adsorbed gas molecules but also the interaction between the adsorbed gas molecule and host framework were found. The information enables us to understand the mechanism of gas adsorption phenomena and functions of PCPs. It will give us the guiding principles for the novel functional materials design. (author)

  16. Rietveld analysis, powder diffraction and cement

    International Nuclear Information System (INIS)

    Peterson, V.

    2002-01-01

    Full text: Phase quantification of cement is essential in its industrial use, however many methods are inaccurate and/or time consuming. Powder diffraction is one of the more accurate techniques used for quantitative phase analysis of cement. There has been an increase in the use of Rietveld refinement and powder diffraction for the analysis and phase quantification of cement and its components in recent years. The complex nature of cement components, existence of solid solutions, polymorphic variation of phases and overlapping phase peaks in diffraction patterns makes phase quantification of cements by powder diffraction difficult. The main phase in cement is alite, a solid solution of tricalcium silicate. Tricalcium silicate has been found to exist in seven modifications in three crystal systems, including triclinic, monoclinic, and rhombohedral structures. Hence, phase quantification of cements using Rietveld methods usually involves the simultaneous modelling of several tricalcium silicate structures to fit the complex alite phase. An industry ordinary Portland cement, industry and standard clinker, and a synthetic tricalcium silicate were characterised using neutron, laboratory x-ray and synchrotron powder diffraction. Diffraction patterns were analysed using full-profile Rietveld refinement. This enabled comparison of x-ray, neutron and synchrotron data for phase quantification of the cement and examination of the tricalcium silicate. Excellent Rietveld fits were achieved, however the results showed that the quantitative phase analysis results differed for some phases in the same clinker sample between various data sources. This presentation will give a short introduction about cement components including polymorphism, followed by the presentation of some problems in phase quantification of cements and the role of Rietveld refinement in solving these problems. Copyright (2002) Australian X-ray Analytical Association Inc

  17. Development and directions of powder diffraction on proteins

    Energy Technology Data Exchange (ETDEWEB)

    Von Dreele, R B; Besnard, C; Basso, S; Camus, F; Pattison, P; Schiltz, M; Wright, J P; Margiolaki, R; Fitch, A N; Fox, G C; Prugoveeki, S; Beckers, D; Helliwell, J R; Helliwell, M; Jones, R H; Roberts, M A; Miura, K; Kahn, R; Giacovazzo, C; Altomare, A; Caliandro, R; Camalli, M; Cuocci, C; Moliterni, A G.G.; Rizzi, R; Hinrichsen, B; Kern, A; Coelho, A A; Degen, T; Kokkinidis, M; Fadouloglou, V; Gazi, A; Panopoulos, N; Pinotsis, N; Wilmanns, M; Norrman, M; Schluckebier, G; Prugoveeki, B; Dilovic, J; Matkovic-Calogovic, D; Bill, David; Markvardsen, A; Grosse-Kunstleve, R; Rius, J; Glykos Nicholas, M; Murshudov, G N

    2007-07-01

    X-ray diffraction is one of the most important method for obtaining information about the structure of proteins and thereby for gaining insight into fundamental biological and biochemical mechanisms. This seminar was dedicated to X-ray powder diffraction and was organized around 6 sessions: 1) what can powder diffraction do for proteins?, 2) adapting experimentally to proteins, 3) interpreting powder data, 4) the world of protein crystallography, 5) advancing methods for powder data analysis, and 6) transferable methods from single crystals. This document gathers the abstracts of the 23 papers presented. (A.C.)

  18. Development and directions of powder diffraction on proteins

    International Nuclear Information System (INIS)

    Von Dreele, R.B.; Besnard, C.; Basso, S.; Camus, F.; Pattison, P.; Schiltz, M.; Wright, J.P.; Margiolaki, R.; Fitch, A.N.; Fox, G.C.; Prugoveeki, S.; Beckers, D.; Helliwell, J.R.; Helliwell, M.; Jones, R.H.; Roberts, M.A.; Miura, K.; Kahn, R.; Giacovazzo, C.; Altomare, A.; Caliandro, R.; Camalli, M.; Cuocci, C.; Moliterni, A.G.G.; Rizzi, R.; Hinrichsen, B.; Kern, A.; Coelho, A.A.; Degen, T.; Kokkinidis, M.; Fadouloglou, V.; Gazi, A.; Panopoulos, N.; Pinotsis, N.; Wilmanns, M.; Norrman, M.; Schluckebier, G.; Prugoveeki, B.; Dilovic, J.; Matkovic-Calogovic, D.; Bill, David; Markvardsen, A.; Grosse-Kunstleve, R.; Rius, J.; Glykos Nicholas, M.; Murshudov, G.N.

    2007-01-01

    X-ray diffraction is one of the most important method for obtaining information about the structure of proteins and thereby for gaining insight into fundamental biological and biochemical mechanisms. This seminar was dedicated to X-ray powder diffraction and was organized around 6 sessions: 1) what can powder diffraction do for proteins?, 2) adapting experimentally to proteins, 3) interpreting powder data, 4) the world of protein crystallography, 5) advancing methods for powder data analysis, and 6) transferable methods from single crystals. This document gathers the abstracts of the 23 papers presented. (A.C.)

  19. Time-resolved Neutron Powder Diffraction

    International Nuclear Information System (INIS)

    Pannetier, J.

    1986-01-01

    The use of a high-flux neutron source together with a large position sensitive detector (PSD) allows a powder diffraction pattern to be recorded at a time-scale of a few minutes so that crystalline systems under non-equilibrium conditions may now conveniently be investigated. This introduces a new dimension into powder diffraction (the time and transient phenomena like heterogeneous chemical reactions can now be easily studied. The instrumental parameters relevant for the design of such time-dependent experiments are briefly surveyed and the current limits of the method are discussed. The applications are illustrated by two kinds of experiment in the field of inorganic solid state chemistry: true kinetic studies of heterogeneous chemical reactions and thermodiffractometry experiments

  20. Homogeneity characterisation of (U,Gd)O2 sintered pellets by X-ray diffraction powder analysis applying Rietveld method

    International Nuclear Information System (INIS)

    Leyva, Ana G.; Vega, Daniel R.; Trimarco, Veronica G.; Marchi, Daniel E.

    1999-01-01

    The (U,Gd)O 2 sintered pellets are fabricated by different methods. The homogeneity characterisation of Gd content seems to be necessary as a production control to qualify the process and the final product. The micrographic technique is the most common method used to analyse the homogeneity of these samples, this method requires time and expertise to obtain good results. In this paper, we propose an analysis of the X-ray diffraction powder patterns through the Rietveld method, in which the differences between the experimental data and the calculated from a crystalline structure model proposed are evaluated. This result allows to determine the cell parameters, that can be correlated with the Gd concentration, and the existence of other phases with different Gd ratio. (author)

  1. Ninety Years of Powder Diffraction: from Birth to Maturity

    International Nuclear Information System (INIS)

    Paszkowicz, W.

    2006-01-01

    The expression ''powder diffraction '' denotes the phenomenon of diffraction of any electromagnetic waves or particles on polycrystalline (powdered, bulk or thin film) materials which is used in a wide variety experimental settings. The X-ray powder-diffraction method was devised and developed during the First World War (1916) by a Dutch/Swiss team, Peter Debye and Paul Scherrer, in Goettingen, Germany, and independently, marginally later, by an American, Albert W. Hull in Schenectady, USA. The birth of powder diffraction came four years after the discovery of the phenomenon of single-crystal diffraction made in 1912 by Walther Friedrich, Paul Knipping and Max Laue in Munich and developed from 1912/1913 by William Henry Bragg (father) and William Lawrence Bragg (son), and later by many others. Powder diffraction became a milestone towards an understanding of the nature of materials, especially of those which cannot be prepared in the form of suitable single crystals, and permitted rapid progress in solid state physics and chemistry. The events leading to the discovery of powder-diffraction phenomenon are briefly reviewed. The importance of synchrotron powder diffraction studies, which have developed since 1980s, is emphasised. (author)

  2. Shock diffraction in alumina powder

    International Nuclear Information System (INIS)

    Venz, G.; Killen, P.D.; Page, N.W.

    1996-01-01

    In order to produce complex shaped components by dynamic compaction of ceramic powders detailed knowledge of their response under shock loading conditions is required. This work attempts to provide data on release effects and shock attenuation in 1 μm and 5 μm α-alumina powders which were compacted to between 85 % and 95 % of the solid phase density by the impact of high velocity steel projectiles. As in previous work, the powder was loaded into large cylindrical dies with horizontal marker layers of a contrasting coloured powder to provide a record of powder displacement in the recovered specimens. After recovery and infiltration with a thermosetting resin the specimens were sectioned and polished to reveal the structure formed by the passage of the projectile and shock wave. Results indicate that the shock pressures generated were of the order of 0.5 to 1.4 GPa and higher, with shock velocities and sound speeds in the ranges 650 to 800 m/s and 350 to 400 m/s respectively

  3. Real-time method of powder diffraction for non-periodic and nearly periodic materials

    International Nuclear Information System (INIS)

    Egami, T.; Toby, B.H.; Dmowski, T.W.; Jorgensen, J.D.

    1989-12-01

    The use of high-energy neutrons from pulsed or hot sources allows the method of atomic pair distribution analysis to be applied to the structural determination of crystalline as well as amorphous solids. This method complements the standard crystallographic methods in studying non-periodic aspects of solids with or without long range order. 14 refs., 3 figs

  4. Real space method of powder diffraction for non-periodic and nearly periodic materials

    International Nuclear Information System (INIS)

    Egami, T.; Toby, B.H.; Dmowski, W.; Janot, C.; Jorgensen, J.D.

    1990-01-01

    The use of high-energy neutrons from pulsed or hot sources allows the method of atomic pair distribution analysis to be applied to the structural determination of crystalline as well as amorphous solids. This method complements the standard crystallographic methods in studying non-periodic aspects of solids with or without long range order

  5. High resolution Neutron and Synchrotron Powder Diffraction

    International Nuclear Information System (INIS)

    Hewat, A.W.

    1986-01-01

    The use of high-resolution powder diffraction has grown rapidly in the past years, with the development of Rietveld (1967) methods of data analysis and new high-resolution diffractometers and multidetectors. The number of publications in this area has increased from a handful per year until 1973 to 150 per year in 1984, with a ten-year total of over 1000. These papers cover a wide area of solid state-chemistry, physics and materials science, and have been grouped under 20 subject headings, ranging from catalysts to zeolites, and from battery electrode materials to pre-stressed superconducting wires. In 1985 two new high-resolution diffractometers are being commissioned, one at the SNS laboratory near Oxford, and one at the ILL in Grenoble. In different ways these machines represent perhaps the ultimate that can be achieved with neutrons and will permit refinement of complex structures with about 250 parameters and unit cell volumes of about 2500 Angstrom/sp3/. The new European Synchotron Facility will complement the Grenoble neutron diffractometers, and extend the role of high-resolution powder diffraction to the direct solution of crystal structures, pioneered in Sweden

  6. Powder diffraction from a continuous microjet of submicrometer protein crystals.

    Science.gov (United States)

    Shapiro, D A; Chapman, H N; Deponte, D; Doak, R B; Fromme, P; Hembree, G; Hunter, M; Marchesini, S; Schmidt, K; Spence, J; Starodub, D; Weierstall, U

    2008-11-01

    Atomic-resolution structures from small proteins have recently been determined from high-quality powder diffraction patterns using a combination of stereochemical restraints and Rietveld refinement [Von Dreele (2007), J. Appl. Cryst. 40, 133-143; Margiolaki et al. (2007), J. Am. Chem. Soc. 129, 11865-11871]. While powder diffraction data have been obtained from batch samples of small crystal-suspensions, which are exposed to X-rays for long periods of time and undergo significant radiation damage, the proof-of-concept that protein powder diffraction data from nanocrystals of a membrane protein can be obtained using a continuous microjet is shown. This flow-focusing aerojet has been developed to deliver a solution of hydrated protein nanocrystals to an X-ray beam for diffraction analysis. This method requires neither the crushing of larger polycrystalline samples nor any techniques to avoid radiation damage such as cryocooling. Apparatus to record protein powder diffraction in this manner has been commissioned, and in this paper the first powder diffraction patterns from a membrane protein, photosystem I, with crystallite sizes of less than 500 nm are presented. These preliminary patterns show the lowest-order reflections, which agree quantitatively with theoretical calculations of the powder profile. The results also serve to test our aerojet injector system, with future application to femtosecond diffraction in free-electron X-ray laser schemes, and for serial crystallography using a single-file beam of aligned hydrated molecules.

  7. Advances in powder diffraction crystallography

    International Nuclear Information System (INIS)

    Magneli, A.

    1986-01-01

    This is the first conference to be arranged within the framework of an agreement on scientific exchange and co-operation between l Academie des Sciences de l Institut de France and the Royal Swedish Academy of Sciences. The responsibility for the scientific program of the conference has been shared between members of the two Academies. The contributions include glimpses of the historical background and broad reviews of the present status of development and of recent work in powder crystallography. Reports are given on a number of studies, basic as well as applied in character, currently conducted in the two countries in a large variety of fields. Prospects of further developments in the area are also presented

  8. The peak in neutron powder diffraction

    International Nuclear Information System (INIS)

    Laar, B. van; Yelon, W.B.

    1984-01-01

    For the application of Rietveld profile analysis to neutron powder diffraction data a precise knowledge of the peak profile, in both shape and position, is required. The method now in use employs a Gaussian shaped profile with a semi-empirical asymmetry correction for low-angle peaks. The integrated intensity is taken to be proportional to the classical Lorentz factor calculated for the X-ray case. In this paper an exact expression is given for the peak profile based upon the geometrical dimensions of the diffractometer. It is shown that the asymmetry of observed peaks is well reproduced by this expression. The angular displacement of the experimental profile with respect to the nominal Bragg angle value is larger than expected. Values for the correction to the classical Lorentz factor for the integrated intensity are given. The exact peak profile expression has been incorporated into a Rietveld profile analysis refinement program. (Auth.)

  9. Application of Powder Diffraction Methods to the Analysis of the Atomic Structure of Nanocrystals: The Concept of the Apparent Lattice Parameter (ALP)

    Science.gov (United States)

    Palosz, B.; Grzanka, E.; Gierlotka, S.; Stelmakh, S.; Pielaszek, R.; Bismayer, U.; Weber, H.-P.; Palosz, W.; Curreri, Peter A. (Technical Monitor)

    2002-01-01

    The applicability of standard methods of elaboration of powder diffraction data for determination of the structure of nano-size crystallites is analysed. Based on our theoretical calculations of powder diffraction data we show, that the assumption of the infinite crystal lattice for nanocrystals smaller than 20 nm in size is not justified. Application of conventional tools developed for elaboration of powder diffraction data, like the Rietveld method, may lead to erroneous interpretation of the experimental results. An alternate evaluation of diffraction data of nanoparticles, based on the so-called 'apparent lattice parameter' (alp) is introduced. We assume a model of nanocrystal having a grain core with well-defined crystal structure, surrounded by a surface shell with the atomic structure similar to that of the core but being under a strain (compressive or tensile). The two structural components, the core and the shell, form essentially a composite crystal with interfering, inseparable diffraction properties. Because the structure of such a nanocrystal is not uniform, it defies the basic definitions of an unambiguous crystallographic phase. Consequently, a set of lattice parameters used for characterization of simple crystal phases is insufficient for a proper description of the complex structure of nanocrystals. We developed a method of evaluation of powder diffraction data of nanocrystals, which refers to a core-shell model and is based on the 'apparent lattice parameter' methodology. For a given diffraction pattem, the alp values are calculated for every individual Bragg reflection. For nanocrystals the alp values depend on the diffraction vector Q. By modeling different a0tomic structures of nanocrystals and calculating theoretically corresponding diffraction patterns using the Debye functions we showed, that alp-Q plots show characteristic shapes which can be used for evaluation of the atomic structure of the core-shell system. We show, that using a simple

  10. Accurate Charge Densities from Powder Diffraction

    DEFF Research Database (Denmark)

    Bindzus, Niels; Wahlberg, Nanna; Becker, Jacob

    Synchrotron powder X-ray diffraction has in recent years advanced to a level, where it has become realistic to probe extremely subtle electronic features. Compared to single-crystal diffraction, it may be superior for simple, high-symmetry crystals owing to negligible extinction effects and minimal...... peak overlap. Additionally, it offers the opportunity for collecting data on a single scale. For charge densities studies, the critical task is to recover accurate and bias-free structure factors from the diffraction pattern. This is the focal point of the present study, scrutinizing the performance...

  11. Neutron Powder Diffraction and Constrained Refinement

    DEFF Research Database (Denmark)

    Pawley, G. S.; Mackenzie, Gordon A.; Dietrich, O. W.

    1977-01-01

    The first use of a new program, EDINP, is reported. This program allows the constrained refinement of molecules in a crystal structure with neutron diffraction powder data. The structures of p-C6F4Br2 and p-C6F4I2 are determined by packing considerations and then refined with EDINP. Refinement is...

  12. Solving Crystal Structures from Powder Diffraction Data

    DEFF Research Database (Denmark)

    Christensen, A. Nørlund; Lehmann, M. S.; Nielsen, Mogens

    1985-01-01

    High resolution powder data from both neutron and X-ray (synchrotron) sources have been used to estimate the possibility of direct structure determination from powder data. Two known structures were resolved by direct methods with neutron and X-ray data. With synchrotron X-ray data, the measured ...

  13. Crystal structures of new cuprates containing CO3 analyzed by the Rietveld method of neutron powder diffraction

    International Nuclear Information System (INIS)

    Miyazaki, Y.; Yamane, H.; Kajitani, T.; Hiraga, K.; Hirai, T.; Morii, Y.; Funahashi, S.

    1993-01-01

    New compounds containing CO 3 groups, Sr 2 CuO 2 (CO 3 ), (C 0.4 Cu 0.6 )Sr 2 (Y 0.86 Sr 0.14 )Cu 2 O 7 and (C 0.35 Cu 0.65 )Sr 2 (Y 0.73 Ce 0.27 ) 2 Cu 2 O 9 , were prepared as stable phases at 1273-1303 K in a flowing gas of O 2 -CO 2 . The crystal structures of these compounds were refined by means of the Rietveld analysis for neutron powder diffraction data collected using a high resolution powder diffractometer (HRPD) in the JRR-3M reactor hall of the Japan Atomic Energy Research Institute (JAERI). Positions of CO 3 groups were satisfactorily determined. The distances of C-O bonds in the CO 3 groups were around 1.3A and the O-C-O angles were almost equal to the ideal bond angle of 120deg. (author)

  14. Powder Neutron Diffraction and Magnetic structures

    International Nuclear Information System (INIS)

    Vigneron, F.

    1986-01-01

    The determination of the magnetic structures of materials (ferromagnetic, antiferromagnetic, helimagnetic, .) can be achieved only by neutron diffraction. A general survey of the powder technique is given: 2-axis spectrometer and analysis of the magnetic data. For the REBe/sb13/ intermetallic compounds (RE = Rare Earth), commensurate and/or incommensurate magnetic structures are observed and discussed as a function of RE (Gd, Tb, Dy, Ho, Er)

  15. High Resolution Powder Diffraction and Structure Determination

    International Nuclear Information System (INIS)

    Cox, D. E.

    1999-01-01

    It is clear that high-resolution synchrotrons X-ray powder diffraction is a very powerful and convenient tool for material characterization and structure determination. Most investigations to date have been carried out under ambient conditions and have focused on structure solution and refinement. The application of high-resolution techniques to increasingly complex structures will certainly represent an important part of future studies, and it has been seen how ab initio solution of structures with perhaps 100 atoms in the asymmetric unit is within the realms of possibility. However, the ease with which temperature-dependence measurements can be made combined with improvements in the technology of position-sensitive detectors will undoubtedly stimulate precise in situ structural studies of phase transitions and related phenomena. One challenge in this area will be to develop high-resolution techniques for ultra-high pressure investigations in diamond anvil cells. This will require highly focused beams and very precise collimation in front of the cell down to dimensions of 50 (micro)m or less. Anomalous scattering offers many interesting possibilities as well. As a means of enhancing scattering contrast it has applications not only to the determination of cation distribution in mixed systems such as the superconducting oxides discussed in Section 9.5.3, but also to the location of specific cations in partially occupied sites, such as the extra-framework positions in zeolites, for example. Another possible application is to provide phasing information for ab initio structure solution. Finally, the precise determination of f as a function of energy through an absorption edge can provide useful information about cation oxidation states, particularly in conjunction with XANES data. In contrast to many experiments at a synchrotron facility, powder diffraction is a relatively simple and user-friendly technique, and most of the procedures and software for data analysis

  16. Resolution of crystal structures by X-ray and neutrons powder diffraction using global optimisation methods; Resolution des structures cristallines par diffraction des rayons X et neutrons sur poudres en utilisant les methodes d'optimisation globale

    Energy Technology Data Exchange (ETDEWEB)

    Palin, L

    2005-03-15

    We have shown in this work that X-ray diffraction on powder is a powerful tool to analyze crystal structure. The purpose of this thesis is the resolution of crystal structures by X-ray and neutrons diffraction on powder using global optimisation methods. We have studied 3 different topics. The first one is the order-disorder phenomena observed in some globular organic molecular solids. The second is the opiate family of neuropeptides. These neurotransmitters regulate sensory functions including pain and control of respiration in the central nervous system. The aim of our study was to try to determine the crystal structure of Leu-enkephalin and some of its sub-fragments. The determination of the crystal structures has been done performing Monte Carlo simulations. The third one is the location of benzene in a sodium-X zeolite. The zeolite framework was already known and the benzene has been localized by simulated annealing and by the use of maximum entropy maps.

  17. Synchrotron powder diffraction on Aztec blue pigments

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez del Rio, M. [European Synchrotron Radiation Facility, B.P. 220, Grenoble Cedex (France); Gutierrez-Leon, A.; Castro, G.R.; Rubio-Zuazo, J. [Spanish CRG Beamline at the European Synchrotron Radiation Facility, SpLine, B.P. 220, Grenoble Cedex (France); Solis, C. [Universidad Nacional Autonoma de Mexico, Instituto de Fisica, Mexico, D.F. (Mexico); Sanchez-Hernandez, R. [INAH Subdireccion de Laboratorios y Apoyo Academico, Mexico, D.F. (Mexico); Robles-Camacho, J. [INAH Centro Regional Michoacan, Morelia, Michoacan (Mexico); Rojas-Gaytan, J. [INAH Direccion de Salvamento Arqueologico, Naucalpan de Juarez (Mexico)

    2008-01-15

    Some samples of raw blue pigments coming from an archaeological rescue mission in downtown Mexico City have been characterized using different techniques. The samples, some recovered as a part of a ritual offering, could be assigned to the late Aztec period (XVth century). The striking characteristic of these samples is that they seem to be raw pigments prior to any use in artworks, and it was possible to collect a few {mu}g of pigment after manual grain selection under a microscopy monitoring. All pigments are made of indigo, an organic colorant locally known as anil or xiuhquilitl. The colorant is always found in combination with an inorganic matrix, studied by powder diffraction. In one case the mineral base is palygorskite, a rare clay mineral featuring micro-channels in its structure, well known as the main ingredient of the Maya blue pigment. However, other samples present the minerals sepiolite (a clay mineral of the palygorskite family) and calcite. Another sample contains barite, a mineral never reported in prehispanic paints. We present the results of characterization using high resolution powder diffraction recorded at the European Synchrotron Radiation Facility (BM25A, SpLine beamline) complemented with other techniques. All of them gave consistent results on the composition. A chemical test on resistance to acids was done, showing a high resistance for the palygorskite and eventually sepiolite compounds, in good agreement with the excellent resistance of the Maya blue. (orig.)

  18. Synchrotron powder diffraction on Aztec blue pigments

    Science.gov (United States)

    Sánchez Del Río, M.; Gutiérrez-León, A.; Castro, G. R.; Rubio-Zuazo, J.; Solís, C.; Sánchez-Hernández, R.; Robles-Camacho, J.; Rojas-Gaytán, J.

    2008-01-01

    Some samples of raw blue pigments coming from an archaeological rescue mission in downtown Mexico City have been characterized using different techniques. The samples, some recovered as a part of a ritual offering, could be assigned to the late Aztec period (XVth century). The striking characteristic of these samples is that they seem to be raw pigments prior to any use in artworks, and it was possible to collect a few μg of pigment after manual grain selection under a microscopy monitoring. All pigments are made of indigo, an organic colorant locally known as añil or xiuhquilitl. The colorant is always found in combination with an inorganic matrix, studied by powder diffraction. In one case the mineral base is palygorskite, a rare clay mineral featuring micro-channels in its structure, well known as the main ingredient of the Maya blue pigment. However, other samples present the minerals sepiolite (a clay mineral of the palygorskite family) and calcite. Another sample contains barite, a mineral never reported in prehispanic paints. We present the results of characterization using high resolution powder diffraction recorded at the European Synchrotron Radiation Facility (BM25A, SpLine beamline) complemented with other techniques. All of them gave consistent results on the composition. A chemical test on resistance to acids was done, showing a high resistance for the palygorskite and eventually sepiolite compounds, in good agreement with the excellent resistance of the Maya blue.

  19. Pulsed Neutron Powder Diffraction for Materials Science

    Science.gov (United States)

    Kamiyama, T.

    2008-03-01

    The accelerator-based neutron diffraction began in the end of 60's at Tohoku University which was succeeded by the four spallation neutron facilities with proton accelerators at the High Energy Accelerator Research Organization (Japan), Argonne National Laboratory and Los Alamos Laboratory (USA), and Rutherford Appleton Laboratory (UK). Since then, the next generation source has been pursued for 20 years, and 1MW-class spallation neutron sources will be appeared in about three years at the three parts of the world: Japan, UK and USA. The joint proton accelerator project (J-PARC), a collaborative project between KEK and JAEA, is one of them. The aim of the talk is to describe about J-PARC and the neutron diffractometers being installed at the materials and life science facility of J-PARC. The materials and life science facility of J-PARC has 23 neutron beam ports and will start delivering the first neutron beam of 25 Hz from 2008 May. Until now, more than 20 proposals have been reviewed by the review committee, and accepted proposal groups have started to get fund. Those proposals include five polycrystalline diffractometers: a super high resolution powder diffractometer (SHRPD), a 0.2%-resolution powder diffractometer of Ibaraki prefecture (IPD), an engineering diffractometers (Takumi), a high intensity S(Q) diffractometer (VSD), and a high-pressure dedicated diffractometer. SHRPD, Takumi and IPD are being designed and constructed by the joint team of KEK, JAEA and Ibaraki University, whose member are originally from the KEK powder group. These three instruments are expected to start in 2008. VSD is a super high intensity diffractometer with the highest resolution of Δd/d = 0.3%. VSD can measure rapid time-dependent phenomena of crystalline materials as well as glass, liquid and amorphous materials. The pair distribution function will be routinely obtained by the Fourier transiformation of S(Q) data. Q range of VSD will be as wide as 0.01 Å-1stress mapping inside

  20. Modern trends in x-ray powder diffraction

    International Nuclear Information System (INIS)

    Goebel, H.E.; Snyder, R.L.

    1985-01-01

    The revival of interest in X-ray powder diffraction, being quoted as a metamorphosis from the 'ugly duckling' to a 'beautiful swan', can be attributed to a number of modern developments in instrumentation and evaluation software. They result in faster data collection, improved accuracy and resolution, and better detectability of minor phases. The ease of data evaluation on small computers coupled direct to the instrument allows convenient execution of previously tedious and time-consuming off-line tasks like qualitative and quantitative analysis, characterization of microcrystalline properties, indexing, and lattice-constant refinements, as well as structure refinements or even exploration of new crystal structures. Powder diffraction has also progressed from an isolated analytical laboratory method to an in situ technique for analysing solid-state reactions or for the on-stream control of industrial processes. The paper surveys these developments and their real and potential applications, and tries to emphasize new trends that are regarded as important steps for the further progress of X-ray powder diffraction

  1. Structure determination of modulated structures by powder X-ray diffraction and electron diffraction

    Czech Academy of Sciences Publication Activity Database

    Zhou, Z.Y.; Palatinus, Lukáš; Sun, J.L.

    2016-01-01

    Roč. 3, č. 11 (2016), s. 1351-1362 ISSN 2052-1553 Institutional support: RVO:68378271 Keywords : electron diffraction * incommensurate structure * powder diffraction Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 4.036, year: 2016

  2. Unit-cell refinement from powder diffraction scans

    International Nuclear Information System (INIS)

    Pawley, G.S.

    1981-01-01

    A procedure for the refinement of the crystal unit cell from a powder diffraction scan is presented. In this procedure knowledge of the crystal structure is not required, and at the end of the refinement a list of indexed intensities is produced. This list may well be usable as the starting point for the application of direct methods. The problems of least-squares ill-conditioning due to overlapping reflections are overcome by constraints. An example using decafluorocyclohexene, C 6 F 10 , shows the quality of fit obtained in a case which may even be a false minimum. The method should become more relevant as powder scans of improved resolution become available, through the use of pulsed neutron sources. (Auth.)

  3. Powder diffraction studies using anomalous dispersion

    International Nuclear Information System (INIS)

    Cox, D.E.; Wilkinson, A.P.

    1993-01-01

    With the increasing availability and accessibility of high resolution powder diffractometers at many synchrotron radiation sources throughout the world, there is rapidly-growing interest in the exploitation of anomalous dispersion techniques for structural studies of polycrystalline materials. In conjunction with the Rietveld profile method for structure refinement, such studies are especially useful for the determination of the site distributions of two or more atoms which are near neighbors in the periodic table, or atoms which are distributed among partially occupied sites. Additionally, it is possible to (1) determine the mean-square displacements associated with different kinds of atoms distributed over a single set of sites, (2) distinguish between different oxidation states and coordination geometries of a particular atom in a compound and (3) to determine f' for a wide range of atomic species as a function of energy in the vicinity of an absorption edge. Experimental methods for making anomalous dispersion measurements are described in some detail, including data collection strategies, data analysis and correlation problems, possible systematic errors, and the accuracy of the results. Recent work in the field is reviewed, including cation site-distribution studies (e.g. doped high T c superconductors, ternary alloys, FeCo 2 (PO 4 ) 3 , FeNi 2 BO 5 ), oxidation-state contrast (e.g. YBa 2 Cu 3 O 6+x , Eu 3 O 4 , GaCl 2 , Fe 2 PO 5 ), and the effect of coordination geometry (e.g. Y 3 Ga 5 O l2 )

  4. Study of properties of chemically modified samples of halloysite mineral with X-ray fluorescence and X-ray powder diffraction methods

    International Nuclear Information System (INIS)

    Banaś, D.; Kubala-Kukuś, A.; Braziewicz, J.; Majewska, U.; Pajek, M.; Wudarczyk-Moćko, J.; Czech, K.; Garnuszek, M.; Słomkiewicz, P.; Szczepanik, B.

    2013-01-01

    Elemental and chemical composition of raw and activated samples of halloysite mineral using wavelength dispersive X-ray fluorescence (WDXRF), total reflection X-ray fluorescence (TXRF) and X-ray powder diffraction (XRPD) methods were determined. As the result, it has been shown that application of the complementary X-ray spectrometry techniques allows very precise observation of changes in composition of halloysite mineral samples caused by its chemical modifications. Sample preparation procedure and usability of the research methods applied are described in details. Procedure of activation of raw halloysite mineral samples by etching them in sulfuric acid of various concentrations has been described and discussed. The ability of the samples to adsorb lead from intentionally contaminated water was tested and confirmed. - Author-Highlights: • We measured elemental and chemical composition of raw and activated halloysite mineral samples. • We showed that X-ray techniques allow precise study of changes in the sample composition. • We describe procedure of activation of the samples by etching them in sulfuric acid. • We tested ability of halloysite mineral to absorb lead from contaminated water

  5. Nanocrystallite characterization of milled simulated dry process fuel powders by neutron diffraction

    International Nuclear Information System (INIS)

    Ryu, Ho Jin; Kang, Kwon Ho; Moon, Je Sun; Song, Kee Chan; Choi, Yong Nam

    2003-01-01

    The nano-scale crystallite sizes of simulated spent fuel powders were measured by the neutron diffraction line broadening method in order to analyze the sintering behavior of the dry process fuel. The mixed U0 2 and fission product oxide powders were dry-milled in an attritor for 30, 60, and 120 min. The diffraction patterns of the powders were obtained by using the high resolution powder diffractometer in the HANARO research reactor. Diffraction line broadening due to crystallite size was measured using various techniques such as the Stokes' deconvolution, profile fitting methods using Cauchy function, Gaussian function, and Voigt function, and the Warren-Averbach method. The r.m.s. strain, stacking fault, twin and dislocation density were measured using the information from the diffraction pattern. The realistic crystallite size can be obtained after separation of the contribution from the non-uniform strain, stacking fault and twin

  6. High pressure neutron powder diffraction at LANSCE

    International Nuclear Information System (INIS)

    Von Dreele, R.B.

    1994-01-01

    By making use of the recently developed ''Paris-Edinburgh'' high pressure cell, the author has successfully performed neutron powder experiments to 10GPa at ambient temperature. Results for the structural compression of the high Tc 1223-Hg superconductor to 9.2 GPa, the compression and possible hydrogen bond formation in brucite, Mg(OD) 2 , to 9.3 GPa, and the molecular reorientation in nitromethane to 5.5 GPa will be presented

  7. Development of materials science by Ab initio powder diffraction analysis

    International Nuclear Information System (INIS)

    Fujii, Kotaro

    2015-01-01

    Crystal structure is most important information to understand properties and behavior of target materials. Technique to analyze unknown crystal structures from powder diffraction data (ab initio powder diffraction analysis) enables us to reveal crystal structures of target materials even we cannot obtain a single crystal. In the present article, three examples are introduced to show the power of this technique in the field of materials sciences. The first example is dehydration/hydration of the pharmaceutically relevant material erythrocycin A. In this example, crystal structures of two anhydrous phases were determined from synchrotron X-ray powder diffraction data and their different dehydration/hydration properties were understood from the crystal structures. In the second example, a crystal structure of a three dimensional metal-organic-framework prepared by a mechanochemical reaction was determined from laboratory X-ray powder diffraction data and the reaction scheme has been revealed. In the third example, a crystal structure of a novel oxide-ion conductor of a new structure family was determined from synchrotron X-ray and neutron powder diffraction data which gave an important information to understand the mechanism of the oxide-ion conduction. (author)

  8. A general method for baseline-removal in ultrafast electron powder diffraction data using the dual-tree complex wavelet transform

    Directory of Open Access Journals (Sweden)

    Laurent P. René de Cotret

    2017-07-01

    Full Text Available The general problem of background subtraction in ultrafast electron powder diffraction (UEPD is presented with a focus on the diffraction patterns obtained from materials of moderately complex structure which contain many overlapping peaks and effectively no scattering vector regions that can be considered exclusively background. We compare the performance of background subtraction algorithms based on discrete and dual-tree complex (DTCWT wavelet transforms when applied to simulated UEPD data on the M1–R phase transition in VO2 with a time-varying background. We find that the DTCWT approach is capable of extracting intensities that are accurate to better than 2% across the whole range of scattering vector simulated, effectively independent of delay time. A Python package is available.

  9. Analysis of the average poly-cyclic aromatic unit in a meta-anthracite coal using conventional x-ray powder diffraction and intensity separation methods

    International Nuclear Information System (INIS)

    Wertz, D.L.; Bissell, M.

    1994-01-01

    X-ray characterizations of coals and coal products have occurred for many years. Hirsch and Cartz measured the diffraction from several coals over the reciprocal space region from s = 0.12 angstrom -1 to 7.5 angstrom -1 where s = (4π/λ) sinΘ. In these studies, a 9 cm powder camera was used to study the high angle region, and a transmission type focusing camera equipped with a LiF monochromator was used for the low angle measurements. They reported that the height of the graphene peak measured for each coal is proportional to the % carbon in the coals. Hirsch also suggested that the ontyberem anthracite has a lamellar diameter of ca. 16 angstrom corresponding to an aromatic lamellae of ca. C 87 . For coals with lower carbon content, Hirsch proposed much smaller lamellae; C 19 for a coal with 80% carbon, and C 24 for a coal with 89% carbon. The subject coal for this study is a meta-anthracite which was derived from the Portsmouth, RI mine. The Narragansett Basin contains anthracite and meta-anthracite coals of Pennsylvanian Age. The Basin was a techtonically active non-marine coal-forming basin which has been impacted by several tectonic events. Because of the importance placed by coal scientists no correctly characterizing the nature of the micro-level structural cluster(s) in coals and because of improvements in both x-ray experimentation capabilities and computing power, we have measured the x-ray diffraction and scattering produced from irradiation of this meta-anthracite coal which contains about 94% aromatic carbon. The goal of our study is to determine the intra-planar, and where possible, inter-planar structural details of coals. To accomplish this goal we have utilized the methods normally used for the molecular analysis of non-crystalline condensed phases such as liquids, solutions, and amorphous solids. Reported herein are the results obtained from the high angle x-ray analysis of this coal

  10. The refractive-index correction in powder diffraction

    International Nuclear Information System (INIS)

    Hart, M.; Parrish, W.; Bellotto, M.; Lim, G.S.

    1988-01-01

    Throughout the history of powder diffraction practice there has been uncertainty about whether or not a refractive-index correction should be made to Bragg's law. High-precision Bragg-angle measurements have been performed with synchrotron radiation on SRM-640 silicon powders at glancing angles; it is found that little or no correction is necessary for the usual 2θ angle range. (orig.)

  11. Polarized neutron powder diffraction studies of antiferromagnetic order in bulk and nanoparticle NiO

    DEFF Research Database (Denmark)

    Brok, Erik; Lefmann, Kim; Deen, Pascale P.

    2015-01-01

    surface contribution to the magnetic anisotropy. Here we explore the potential use of polarized neutron diffraction to reveal the magnetic structure in NiO bulk and nanoparticle powders by applying the XYZ-polarization analysis method. Our investigations address in particular the spin orientation in bulk....... The results show that polarization analyzed neutron powder diffraction is a viable method to investigate magnetic order in powders of antiferromagnetic nanoparticles.......In many materials it remains a challenge to reveal the nature of magnetic correlations, including antiferromagnetism and spin disorder. Revealing the spin structure in magnetic nanoparticles is further complicated by the large incoherent neutron scattering cross section from water adsorbed...

  12. Applications of neutron powder diffraction in materials research

    International Nuclear Information System (INIS)

    Kennedy, S.J.

    1996-01-01

    The aim of this article is to provide an overview of the applications of neutron powder diffraction in materials science. The technique is introduced with particular attention to comparison with the X-ray powder diffraction technique to which it is complementary. The diffractometers and special environment ancillaries operating around the HIFAR research reactor at the Australian Nuclear Science and Technology Organisation (ANSTO) are described. Applications of the technique which the advantage of the unique properties of thermal neutrons have been selected from recent materials studies undertaken at ANSTO

  13. X-ray powder diffraction data on miscellaneous lanthanide compounds

    International Nuclear Information System (INIS)

    Ferguson, I.F.; Hughes, T.E.

    1978-08-01

    Recent work on neutron absorbing materials has produced various new X-ray diffraction powder patterns of compounds of the lanthanides. Various inconsistencies in previously published data have been noted, and accurate measurements have been made of the lattice parameters of the rare earth oxides Sm 2 0 3 , Eu 2 0 3 , Gd 2 0 3 which have the monoclinic rare earth type B- structure, as well as Eu0. These data are recorded for reference. The optimum conditions for obtaining X-ray powder diffraction data from europium compounds are also noted. (author)

  14. High-resolution neutron powder-diffraction in CMR manganates

    Energy Technology Data Exchange (ETDEWEB)

    Suard, E; Radaelli, P G [Institut Max von Laue - Paul Langevin (ILL), 38 - Grenoble (France)

    1997-04-01

    Manganese-oxide materials have recently been the subject of renewed attention, due to the `colossal` magnetoresistance (CMR) displayed near the spin-ordering temperature T{sub c} by some of these compounds. CMR has been evidenced in at least three families of manganese oxides. In most cases, the CMR compounds behave as paramagnetic semiconductors at high temperatures, and as ferromagnetic metals below T{sub c}. The study of this metallization process has lead some theorists to challenge its traditional interpretation in terms of the so-called double-exchange mechanism, and to propose alternative scenarios in which the coupling of the charge carriers with the lattice plays a paramount role. Powder diffraction method, being at the forefront of CMR research is presented. (author). 4 refs.

  15. Frequency analysis for modulation-enhanced powder diffraction.

    Science.gov (United States)

    Chernyshov, Dmitry; Dyadkin, Vadim; van Beek, Wouter; Urakawa, Atsushi

    2016-07-01

    Periodic modulation of external conditions on a crystalline sample with a consequent analysis of periodic diffraction response has been recently proposed as a tool to enhance experimental sensitivity for minor structural changes. Here the intensity distributions for both a linear and nonlinear structural response induced by a symmetric and periodic stimulus are analysed. The analysis is further extended for powder diffraction when an external perturbation changes not only the intensity of Bragg lines but also their positions. The derived results should serve as a basis for a quantitative modelling of modulation-enhanced diffraction data measured in real conditions.

  16. American Crystallographic Association Project: numerical ratings of powder diffraction patterns

    International Nuclear Information System (INIS)

    Smith, G.S.; Snyder, R.L.

    1977-01-01

    At present, nearly 30,000 powder diffraction patterns are available as references. It is proposed that the patterns in this file as well as new patterns submitted for publication be given quantitative quality factors. A simple-to-use figure of merit, F/sub N/, covering both accuracy of d-values and completeness of a pattern was derived. This figure of merit provides the user with a means of rapid evaluation of powder patterns in much the same way that the R-factor does for single-crystal structure determinations. The present F/sub N/ ranking scheme is shown to be superior to de Wolff's M 20 ranking scheme. It is recommended that the latter be discontinued. Guidelines are given on the use and implementation of F/sub N/ rating of powder diffraction patterns

  17. Method to blend separator powders

    Science.gov (United States)

    Guidotti, Ronald A.; Andazola, Arthur H.; Reinhardt, Frederick W.

    2007-12-04

    A method for making a blended powder mixture, whereby two or more powders are mixed in a container with a liquid selected from nitrogen or short-chain alcohols, where at least one of the powders has an angle of repose greater than approximately 50 degrees. The method is useful in preparing blended powders of Li halides and MgO for use in the preparation of thermal battery separators.

  18. Fundamentals of powder x-ray diffraction practice

    International Nuclear Information System (INIS)

    Raftery, T.

    2002-01-01

    Full text: The goal of powder Xray diffraction is to gain information about a specimen or sample. Key aspects of this goal are 1. the sample selection, preparation and presentation; 2. the data collection process and conditions; 3. the interaction between these and the interpretation of the data. The 'ideal' powder (or polycrystalline) xray diffraction sample is fine grained, randomly orientated, homogenous and representative. There exists standard sample selection and preparation techniques for powders - sometimes however, the required information must be gained by alternate sample selection and preparation techniques. While there are few variables in the data collection process, there are some significant ones such as matching diffractometer resolution and intensity to the data collection goal whether that is phase identity, quantitative analysis or structure refinement, etc. There are also options of optical arrangement (Bragg-Brintano versus parallel beam versus Debye-Scherrer). One important aspect of the collection process is the assessment of the data quality. Powder xray diffraction has many applications from the straight-forward confirmation of phase identity and purity to structural analysis. Some of these applications will be considered and the interaction between the goal of the application and aspects of sample selection. Copyright (2002) Australian X-ray Analytical Association Inc

  19. Application of Powder Diffraction Methods to the Analysis of Short- and Long-Range Atomic Order in Nanocrystalline Diamond and SiC: The Concept of the Apparent Lattice Parameter (alp)

    Science.gov (United States)

    Palosz, B.; Grzanka, E.; Gierlotka, S.; Stelmakh, S.; Pielaszek, R.; Bismayer, U.; Weber, H.-P.; Palosz, W.

    2003-01-01

    Two methods of the analysis of powder diffraction patterns of diamond and SiC nanocrystals are presented: (a) examination of changes of the lattice parameters with diffraction vector Q ('apparent lattice parameter', alp) which refers to Bragg scattering, and (b), examination of changes of inter-atomic distances based on the analysis of the atomic Pair Distribution Function, PDF. Application of these methods was studied based on the theoretical diffraction patterns computed for models of nanocrystals having (i) a perfect crystal lattice, and (ii), a core-shell structure, i.e. constituting a two-phase system. The models are defined by the lattice parameter of the grain core, thickness of the surface shell, and the magnitude and distribution of the strain field in the shell. X-ray and neutron experimental diffraction data of nanocrystalline SiC and diamond powders of the grain diameter from 4 nm up to micrometers were used. The effects of the internal pressure and strain at the grain surface on the structure are discussed based on the experimentally determined dependence of the alp values on the Q-vector, and changes of the interatomic distances with the grain size determined experimentally by the atomic Pair Distribution Function (PDF) analysis. The experimental results lend a strong support to the concept of a two-phase, core and the surface shell structure of nanocrystalline diamond and SiC.

  20. IL 12: Femtosecond x-ray powder diffraction

    International Nuclear Information System (INIS)

    Woerner, M.; Zamponi, F.; Rothhardt, P.; Ansari, Z.; Dreyer, J.; Freyer, B.; Premont-Schwarz, M.; Elsaesser, T.

    2010-01-01

    A chemical reaction generates new compounds out of one or more initial species. On a molecular level, the spatial arrangement of electrons and nuclei changes. While the structure of the initial and the product molecules can be measured routinely, the transient structures and molecular motions during a reaction have remained unknown in most cases. This knowledge, however, is a key element for the exact understanding of the reaction. The ultimate dream is a 'reaction microscope' which allows for an in situ imaging of the molecules during a reaction. We report on the first femtosecond x-ray powder diffraction experiment in which we directly map the transient electronic charge density in the unit cell of a crystalline solid with 30 pico-meter spatial and 100 femtosecond temporal resolution. X-ray diffraction from polycrystalline powder samples, the Debye Scherrer diffraction technique, is a standard method for determining equilibrium structures. The intensity of the Debye Scherrer rings is determined by the respective x-ray structure factor which represents the Fourier transform of the spatial electron density. In our experiments, the transient intensity and angular positions of up to 20 Debye Scherrer reactions from a polycrystalline powder are measured and unravel for the first time a concerted electron and proton transfer in hydrogen-bonded ionic (NH 4 ) 2 SO 4 crystals. Photoexcitation of ammonium sulfate induces a sub-100 fs electron transfer from the sulfate groups into a highly conned electron channel along the z-axis of the unit cell. The latter geometry is stabilized by transferring protons from the adjacent ammonium groups into the channel. Time-dependent charge density maps derived from the diffraction data display a periodic modulation of the channels charge density by low-frequency lattice motions with a concerted electron and proton motion between the channel and the initial proton binding site. A deeper insight into the underlying microscopic

  1. Neutron powder diffraction under high pressure at J-PARC

    International Nuclear Information System (INIS)

    Utsumi, Wataru; Kagi, Hiroyuki; Komatsu, Kazuki; Arima, Hiroshi; Nagai, Takaya; Okuchi, Takuo; Kamiyama, Takashi; Uwatoko, Yoshiya; Matsubayashi, Kazuyuki; Yagi, Takehiko

    2009-01-01

    It is expected that high-pressure material science and the investigation of the Earth's interior will progress greatly using the high-flux pulse neutrons of J-PARC. In this article, we introduce our plans for in situ neutron powder diffraction experiments under high pressure at J-PARC. The use of three different types of high-pressure devices is planned; a Paris-Edinburgh cell, a new opposed-anvil cell with a nano-polycrystalline diamond, and a cubic anvil high-pressure apparatus. These devices will be brought to the neutron powder diffraction beamlines to conduct a 'day-one' high-pressure experiment. For the next stage of research, we propose construction of a dedicated beamline for high-pressure material science. Its conceptual designs are also introduced here.

  2. MacDUST - a powder diffraction package developed for the ''ADONE'' high resolution diffraction station

    International Nuclear Information System (INIS)

    Burattini, E.; Cappuccio, G.; Maistrelli, P.; Simeoni, S.

    1993-01-01

    A High Resolution Powder Diffraction Station (PO.DI.STA.) was installed at the beginning of 1991 on the ADONE-Wiggler magnet beam line. The station and the first powder diffraction spectra, collected with synchrotron radiation, were presented at the EPDIC-1 Conference. More details can also be found in. For this station, a very sophisticated software package ''MacDUST'' has been developed on an Apple Macintosh computer, using the Microsoft QuickBASIC compiler. It allows very easy and comfortable operations by means of a graphical user interface environment, typical of the Macintosh system. The package consists of five major programs. The main program, MacDIFF, performs all the graphic operations on the experimental data, including zooming, overlapping, cursor scanning and editing of patterns, control of output operations to printers and HPGL plotters. It also includes several analysis routines for data smoothing, a first derivative peak search algorithm, two background subtraction routines and two profile fitting programs: one based on the simplex method and the other on the Marquardt modification of a least-square algorithm. MacPDF and MacRIC are both dedicated to phase identification. The first program is an archive manager for searching, displaying and printing phase records; MacRIC is a graphic aided search-match program based on the Hanawalt algorithm. Mac3-DIM is a plot program, useful, e.g., for representing kinetics three dimensionally. MacRIET is a Macintosh version of the well known Rietveld refinement program. This version, besides conventional structure refinements, also allows the determination of micro structural parameters, i.e. micro strain and crystallite size. The program can also be used to simulate a pattern, once the structure of the compound is known. Taking advantage of the very intuitive Macintosh graphic user interface, through dialog and alert boxes, the program allows straightforward introduction and modification of the structure

  3. Assessment of firing conditions in old fired-clay bricks. The contribution of X-ray powder diffraction with the Rietveld method and small angle neutron scattering

    Czech Academy of Sciences Publication Activity Database

    Viani, Alberto; Sotiriadis, Konstantinos; Len, A.; Šašek, Petr; Ševčík, Radek

    2016-01-01

    Roč. 116, June (2016), s. 33-43 ISSN 1044-5803 R&D Projects: GA MŠk(CZ) LO1219 Keywords : fired- clay brick * Rietveld method * small angle neutron scattering * X-ray diffraction * firing temperature Subject RIV: AL - Art, Architecture, Cultural Heritage Impact factor: 2.714, year: 2016 http://www.sciencedirect.com/science/article/pii/S1044580316300870

  4. Profile analysis of neutron powder diffraction data at ISIS

    International Nuclear Information System (INIS)

    David, W.I.F.; Ibberson, R.M.; Matthewman, J.C.

    1992-05-01

    The aim of this manual is to document the current suite of time-of-flight neutron powder diffraction profile refinement programs available to ISIS users. Aspects of data collation and normalisation specific to the individual diffraction instruments are dealt with elsewhere. It will be assumed the user has produced a suitable data file (.DAT file) containing the profile data consisting of point by point values of the corrected diffraction profile across the pattern. The analysis of neutron powder diffraction data at ISIS by profile refinement utilises a suite of ''in-house'' written and supported programs based on the Cambridge Crystallography Subroutine Library (CCSL). A quick scan through the CCSL manual will give the user a general feel for the procedure to adopt in the use of the library and hence of the profile codes. The instructions documented in this handbook are complementary to those in the more specialist CCSL manual, and consequently go into no great detail regarding technical details of any of the CCSL routines. The programs may be run from each individual user account, for example [USER01], once the appropriate login procedure has been set-up by the instrument scientists. The programs are mostly activated by one line commands and only a basic knowledge of a VAX editor should be required; details can be found in the ''VAX primer'' available from Computer Support. (Author)

  5. Digital Image Correlation of 2D X-ray Powder Diffraction Data for Lattice Strain Evaluation

    Directory of Open Access Journals (Sweden)

    Hongjia Zhang

    2018-03-01

    Full Text Available High energy 2D X-ray powder diffraction experiments are widely used for lattice strain measurement. The 2D to 1D conversion of diffraction patterns is a necessary step used to prepare the data for full pattern refinement, but is inefficient when only peak centre position information is required for lattice strain evaluation. The multi-step conversion process is likely to lead to increased errors associated with the ‘caking’ (radial binning or fitting procedures. A new method is proposed here that relies on direct Digital Image Correlation analysis of 2D X-ray powder diffraction patterns (XRD-DIC, for short. As an example of using XRD-DIC, residual strain values along the central line in a Mg AZ31B alloy bar after 3-point bending are calculated by using both XRD-DIC and the conventional ‘caking’ with fitting procedures. Comparison of the results for strain values in different azimuthal angles demonstrates excellent agreement between the two methods. The principal strains and directions are calculated using multiple direction strain data, leading to full in-plane strain evaluation. It is therefore concluded that XRD-DIC provides a reliable and robust method for strain evaluation from 2D powder diffraction data. The XRD-DIC approach simplifies the analysis process by skipping 2D to 1D conversion, and opens new possibilities for robust 2D powder diffraction data analysis for full in-plane strain evaluation.

  6. Digital Image Correlation of 2D X-ray Powder Diffraction Data for Lattice Strain Evaluation

    Science.gov (United States)

    Zhang, Hongjia; Sui, Tan; Daisenberger, Dominik; Fong, Kai Soon

    2018-01-01

    High energy 2D X-ray powder diffraction experiments are widely used for lattice strain measurement. The 2D to 1D conversion of diffraction patterns is a necessary step used to prepare the data for full pattern refinement, but is inefficient when only peak centre position information is required for lattice strain evaluation. The multi-step conversion process is likely to lead to increased errors associated with the ‘caking’ (radial binning) or fitting procedures. A new method is proposed here that relies on direct Digital Image Correlation analysis of 2D X-ray powder diffraction patterns (XRD-DIC, for short). As an example of using XRD-DIC, residual strain values along the central line in a Mg AZ31B alloy bar after 3-point bending are calculated by using both XRD-DIC and the conventional ‘caking’ with fitting procedures. Comparison of the results for strain values in different azimuthal angles demonstrates excellent agreement between the two methods. The principal strains and directions are calculated using multiple direction strain data, leading to full in-plane strain evaluation. It is therefore concluded that XRD-DIC provides a reliable and robust method for strain evaluation from 2D powder diffraction data. The XRD-DIC approach simplifies the analysis process by skipping 2D to 1D conversion, and opens new possibilities for robust 2D powder diffraction data analysis for full in-plane strain evaluation. PMID:29543728

  7. Incident spectrum determination for time-of-flight neutron powder diffraction data analysis

    International Nuclear Information System (INIS)

    Hodges, J. P.

    1998-01-01

    Accurate characterization of the incident neutron spectrum is an important requirement for precise Rietveld analysis of time-of-flight powder neutron diffraction data. Without an accurate incident spectrum the calculated model for the measured relative intensities of individual Bragg reflections will possess systematic errors. We describe a method for obtaining an accurate numerical incident spectrum using data from a transmitted beam monitor

  8. X-ray diffraction microstructural analysis of bimodal size distribution MgO nano powder

    International Nuclear Information System (INIS)

    Suminar Pratapa; Budi Hartono

    2009-01-01

    Investigation on the characteristics of x-ray diffraction data for MgO powdered mixture of nano and sub-nano particles has been carried out to reveal the crystallite-size-related microstructural information. The MgO powders were prepared by co-precipitation method followed by heat treatment at 500 degree Celsius and 1200 degree Celsius for 1 hour, being the difference in the temperature was to obtain two powders with distinct crystallite size and size-distribution. The powders were then blended in air to give the presumably bimodal-size- distribution MgO nano powder. High-quality laboratory X-ray diffraction data for the powders were collected and then analysed using Rietveld-based MAUD software using the lognormal size distribution. Results show that the single-mode powders exhibit spherical crystallite size (R) of 20(1) nm and 160(1) nm for the 500 degree Celsius and 1200 degree Celsius data respectively with the nano metric powder displays narrower crystallite size distribution character, indicated by lognormal dispersion parameter of 0.21 as compared to 0.01 for the sub-nano metric powder. The mixture exhibits relatively more asymmetric peak broadening. Analysing the x-ray diffraction data for the latter specimen using single phase approach give unrealistic results. Introducing two phase models for the double-phase mixture to accommodate the bimodal-size-distribution characteristics give R = 100(6) and σ = 0.62 for the nano metric phase and R = 170(5) and σ= 0.12 for the σ sub-nano metric phase. (author)

  9. Powder X-ray diffraction study af alkali alanates

    DEFF Research Database (Denmark)

    Cao, Thao; Mosegaard Arnbjerg, Lene; Jensen, Torben René

    Powder X-ray diffraction study of alkali alanates Thao Cao, Lene Arnbjerg, Torben R. Jensen. Center for Materials Crystallography (CMC), Center for Energy Materials (CEM), iNANO and Department of Chemistry, Aarhus University, DK-8000, Denmark. Abstract: To meet the energy demand in the future...... for mobile applications, new materials with high gravimetric and volumetric storage capacity of hydrogen have to be developed. Alkali alanates are promising for hydrogen storage materials. Sodium alanate stores hydrogen reversibly at moderate conditions when catalysed with, e.g. titanium, whereas potassium...

  10. New synchrotron powder diffraction facility for long-duration experiments.

    Science.gov (United States)

    Murray, Claire A; Potter, Jonathan; Day, Sarah J; Baker, Annabelle R; Thompson, Stephen P; Kelly, Jon; Morris, Christopher G; Yang, Sihai; Tang, Chiu C

    2017-02-01

    A new synchrotron X-ray powder diffraction instrument has been built and commissioned for long-duration experiments on beamline I11 at Diamond Light Source. The concept is unique, with design features to house multiple experiments running in parallel, in particular with specific stages for sample environments to study slow kinetic systems or processes. The instrument benefits from a high-brightness X-ray beam and a large area detector. Diffraction data from the commissioning work have shown that the objectives and criteria are met. Supported by two case studies, the results from months of measurements have demonstrated the viability of this large-scale instrument, which is the world's first dedicated facility for long-term studies (weeks to years) using synchrotron radiation.

  11. Acquiring the fundamentals: an accredited powder diffraction course on the internet

    International Nuclear Information System (INIS)

    Crockcroft, J.K.; Barnes, P.; Attfield, M.P.; Cranswick, L.M.D.

    2002-01-01

    Full text: In August 1999, building on accredited academic-based crystallographic web courses pioneered by Birkbeck College, University of London, for Protein Crystallography and Principles of Protein Structure, a new 'Advanced Certificate in Powder Diffraction' was officially announced at the International Union of Crystallography congress in Glasgow. Offering tuition via the Internet on the fundamentals in powder diffraction, it is now running successfully into its third year. The background of student intake ranges from new PhD students to scientists, technicians and X-ray analysts in commercial companies. The work for this 1 year long course, takes around 6 to 8 hours a week to complete; and should not be considered equivalent to recreational web browsing, but as serious study. If this course is done as part of staff training and development, it is important that the employer recognize this; and that adequate training time is set aside as part of the working week. The 'Advanced Certificate in Powder Diffraction' is assessed by a mixture of 'coursework', computer based data analysis project and a formal written exam taken at a local university. To obtain the full qualification, the exam must be taken, but it is optional if only training and no formal qualification is required. The course content covers a broad range of knowledge required for an 'understanding' of powder diffraction. These include the Internet Skills required to do the course, Diffraction Instrumentation, Laboratory Methods, Synchrotron Sources and Methods, Neutron Sources, Diffraction Theory, Electron Scattering to Structure Factors, Structure Factors to Diffraction Intensities, the concept of Symmetry to 3-D Symmetry Elements, Point Groups, Space Groups, Space-Group Determination, Interpreting the IUCr International Tables, Qualitative Analysis, Quantitative Analysis, Indexing, Unit-Cell Refinement, Peak Shapes, Structure Refinement and the Rietveld Method, Modern Techniques and Applications

  12. The CCP14 for single crystal and powder diffraction

    International Nuclear Information System (INIS)

    Cranswick, L.M.D.

    1999-01-01

    Full text: The Collaborative Computation Project Number 14 for Single Crystal and Powder Diffraction (CCP14) is continuing in its objective to provide freely available software and resources for the powder diffraction and crystallographic community. Using the Internet and World Wide Web, we are presently compiling software and web resources, creating tutorials and help files. It also endeavours to encourage and provide resources to assist program authors with developing their software. The CCP14 presently has its web-site at and a mirror at (at CSIRO, Melbourne, Australia). Auto web-mirroring is being implemented to allow users to obtain software and access to resources in a more time effective manner. For people in countries isolated from the Internet, the CCP14 on CD-ROM can be snail mailed on request. This is in the form of a Virtual World Wide Web/Virtual Internet; in the same vein as the existing Crystallographic Nexus CD-ROM. Copyright (1999) Australian X-ray Analytical Association Inc

  13. Application of powder X-ray diffraction in studying the compaction behavior of bulk pharmaceutical powders.

    Science.gov (United States)

    Bandyopadhyay, Rebanta; Selbo, Jon; Amidon, Gregory E; Hawley, Michael

    2005-11-01

    This study investigates the effects of crystal lattice deformation on the powder X-ray diffraction (PXRD) patterns of compressed polycrystalline specimen (compacts/tablets) made from molecular, crystalline powders. The displacement of molecules and the corresponding adjustment of interplanar distances (d-spacings) between diffracting planes of PNU-288034 and PNU-177553, which have crystal habits with a high aspect ratio favoring preferred orientation during tableting, are demonstrated by shifts in the diffracted peak positions. The direction of shift in diffracted peak positions suggests a reduction of interplanar d-spacing in the crystals of PNU-288034 and PNU-177553 following compaction. There is also a general reduction of peak intensities following compression at the different compressive loads. The lattice strain representing the reduction in d-spacing is proportional to the original d-spacing of the uncompressed sample suggesting that, as with systems that obey a simple Hooke's law relationship, the further apart the planes of atoms/molecules within the lattice are, the easier it is for them to approach each other under compressive stresses. For a third model compound comprising more equant-shaped crystals of PNU-141659, the shift in diffracted peak positions are consistent with an expansion of lattice spacing after compression. This apparent anomaly is supported by the PXRD studies of the bulk powder consisting of fractured crystals where also, the shift in peak position suggests expansion of the lattice planes. Thus the crystals of PNU-141659 may be fracturing under the compressive loads used to produce the compacts. Additional studies are underway to relate the PXRD observations with the bulk tableting properties of these model compounds.

  14. Application of new synchrotron powder diffraction techniques to anomalous scattering from glasses

    International Nuclear Information System (INIS)

    Beno, M.A.; Knapp, G.S.; Armand, P.; Price, D.L.; Saboungi, M.

    1995-01-01

    We have applied two synchrotron powder diffraction techniques to the measurement of high quality anomalous scattering diffraction data for amorphous materials. One of these methods, which uses a curved perfect crystal analyzer to simultaneously diffract multiple powder lines into a position sensitive detector has been shown to possess high resolution, low background, and very high counting rates. This data measurement technique provides excellent energy resolution while minimizing systematic errors resulting from detector nonlinearity. Anomalous scattering data for a Cesium Germanate glass collected using this technique will be presented. The second powder diffraction technique uses a flat analyzer crystal to deflect multiple diffraction lines out of the equatorial plane. Calculations show that this method possesses sufficient energy resolution for anomalous scattering experiments when a perfect crystal analyzer is used and is experimentally much simpler. Future studies will make use of a rapid sample changer allowing the scattering from the sample and a standard material (a material not containing the anomalous scatterer) to be measured alternately at each angle, reducing systematic errors due to beam instability or sample misalignment

  15. Assessment of firing conditions in old fired-clay bricks: The contribution of X-ray powder diffraction with the Rietveld method and small angle neutron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Viani, Alberto, E-mail: viani@itam.cas.cz [Institute of Theoretical and Applied Mechanics AS CR, Centre of Excellence Telč, Batelovská 485, CZ-58856 Telč (Czech Republic); Sotiriadis, Konstantinos [Institute of Theoretical and Applied Mechanics AS CR, Centre of Excellence Telč, Batelovská 485, CZ-58856 Telč (Czech Republic); Len, Adél [Wigner Research Centre for Physics HAS, Konkoly-Thege 29-33, 1121 Budapest (Hungary); Šašek, Petr; Ševčík, Radek [Institute of Theoretical and Applied Mechanics AS CR, Centre of Excellence Telč, Batelovská 485, CZ-58856 Telč (Czech Republic)

    2016-06-15

    Full characterization of fired-clay bricks is crucial for the improvement of process variables in manufacturing and, in case of old bricks, for restoration/replacement purposes. To this aim, five bricks produced in a plant in Czech Republic in the past have been investigated with a combination of analytical techniques in order to derive information on the firing process. An additional old brick from another brickyard was also used to study the influence of different raw materials on sample microstructure. The potential of X-ray diffraction with the Rietveld method and small angle neutron scattering technique has been exploited to describe the phase transformations taking place during firing and characterize the brick microstructure. Unit-cell parameter of spinel and amount of hematite are proposed as indicators of the maximum firing temperature, although for the latter, limited to bricks produced from the same raw material. The fractal quality of the surface area of pores obtained from small angle neutron scattering is also suggested as a method to distinguish between bricks produced from different raw clays. - Highlights: • Rietveld method helps in describing microstructure and physical properties of bricks. • XRPD derived cell parameter of spinel is proposed as an indicator of firing temperature. • SANS effectively describes brick micro and nanostructure, including closed porosity. • Fractal quality of pore surface is proposed as ‘fingerprint’ of brick manufacturing.

  16. Three-dimensional electron diffraction as a complementary technique to powder X-ray diffraction for phase identification and structure solution of powders.

    Science.gov (United States)

    Yun, Yifeng; Zou, Xiaodong; Hovmöller, Sven; Wan, Wei

    2015-03-01

    Phase identification and structure determination are important and widely used techniques in chemistry, physics and materials science. Recently, two methods for automated three-dimensional electron diffraction (ED) data collection, namely automated diffraction tomography (ADT) and rotation electron diffraction (RED), have been developed. Compared with X-ray diffraction (XRD) and two-dimensional zonal ED, three-dimensional ED methods have many advantages in identifying phases and determining unknown structures. Almost complete three-dimensional ED data can be collected using the ADT and RED methods. Since each ED pattern is usually measured off the zone axes by three-dimensional ED methods, dynamic effects are much reduced compared with zonal ED patterns. Data collection is easy and fast, and can start at any arbitrary orientation of the crystal, which facilitates automation. Three-dimensional ED is a powerful technique for structure identification and structure solution from individual nano- or micron-sized particles, while powder X-ray diffraction (PXRD) provides information from all phases present in a sample. ED suffers from dynamic scattering, while PXRD data are kinematic. Three-dimensional ED methods and PXRD are complementary and their combinations are promising for studying multiphase samples and complicated crystal structures. Here, two three-dimensional ED methods, ADT and RED, are described. Examples are given of combinations of three-dimensional ED methods and PXRD for phase identification and structure determination over a large number of different materials, from Ni-Se-O-Cl crystals, zeolites, germanates, metal-organic frameworks and organic compounds to intermetallics with modulated structures. It is shown that three-dimensional ED is now as feasible as X-ray diffraction for phase identification and structure solution, but still needs further development in order to be as accurate as X-ray diffraction. It is expected that three-dimensional ED methods

  17. Three-dimensional electron diffraction as a complementary technique to powder X-ray diffraction for phase identification and structure solution of powders

    Directory of Open Access Journals (Sweden)

    Yifeng Yun

    2015-03-01

    Full Text Available Phase identification and structure determination are important and widely used techniques in chemistry, physics and materials science. Recently, two methods for automated three-dimensional electron diffraction (ED data collection, namely automated diffraction tomography (ADT and rotation electron diffraction (RED, have been developed. Compared with X-ray diffraction (XRD and two-dimensional zonal ED, three-dimensional ED methods have many advantages in identifying phases and determining unknown structures. Almost complete three-dimensional ED data can be collected using the ADT and RED methods. Since each ED pattern is usually measured off the zone axes by three-dimensional ED methods, dynamic effects are much reduced compared with zonal ED patterns. Data collection is easy and fast, and can start at any arbitrary orientation of the crystal, which facilitates automation. Three-dimensional ED is a powerful technique for structure identification and structure solution from individual nano- or micron-sized particles, while powder X-ray diffraction (PXRD provides information from all phases present in a sample. ED suffers from dynamic scattering, while PXRD data are kinematic. Three-dimensional ED methods and PXRD are complementary and their combinations are promising for studying multiphase samples and complicated crystal structures. Here, two three-dimensional ED methods, ADT and RED, are described. Examples are given of combinations of three-dimensional ED methods and PXRD for phase identification and structure determination over a large number of different materials, from Ni–Se–O–Cl crystals, zeolites, germanates, metal–organic frameworks and organic compounds to intermetallics with modulated structures. It is shown that three-dimensional ED is now as feasible as X-ray diffraction for phase identification and structure solution, but still needs further development in order to be as accurate as X-ray diffraction. It is expected that three

  18. In Situ High Resolution Synchrotron X-Ray Powder Diffraction Studies of Lithium Batteries

    DEFF Research Database (Denmark)

    Amri, Mahrez; Fitch, Andy; Norby, Poul

    2015-01-01

    allowing diffraction information to be obtained from only the active material during battery operation [2]. High resolution synchrotron x-ray powder diffraction technique has been undertaken to obtain detailed structural and compositional information during lithiation/delithiation of commercial LiFePO4...... materials [3]. We report results from the first in situ time resolved high resolution powder diffraction experiments at beamline ID22/31 at the European Synchrotron Radiation Facility, ESRF. We follow the structural changes during charge of commercial LiFePO4 based battery materials using the Rietveld...... method. Conscientious Rietveld analysis shows slight but continuous deviation of lattice parameters from those of the fully stoichiometric end members LiFePO4 and FePO4 indicating a subsequent variation of stoichiometry during cathode delithiation. The application of an intermittent current pulses during...

  19. Determination of crystal structures with large known fragments directly from measured X-ray powder diffraction intensities

    International Nuclear Information System (INIS)

    Rius, J.; Miravitlles, C.

    1988-01-01

    A strategy for the determination of crystal structures with large known fragments directly from measured X-ray powder diffraction intensities is presented. It is based on the automated full-symmetry Patterson search method described by Rius and Miravitlles where the Fourier coefficients of the observed Patterson function are modified to allow the use of powder diffraction intensity data. Its application to two structures, one with simulated and one with experimental data, is shown. (orig.)

  20. Powder X-ray diffraction laboratory, Reston, Virginia

    Science.gov (United States)

    Piatak, Nadine M.; Dulong, Frank T.; Jackson, John C.; Folger, Helen W.

    2014-01-01

    The powder x-ray diffraction (XRD) laboratory is managed jointly by the Eastern Mineral and Environmental Resources and Eastern Energy Resources Science Centers. Laboratory scientists collaborate on a wide variety of research problems involving other U.S. Geological Survey (USGS) science centers and government agencies, universities, and industry. Capabilities include identification and quantification of crystalline and amorphous phases, and crystallographic and atomic structure analysis for a wide variety of sample media. Customized laboratory procedures and analyses commonly are used to characterize non-routine samples including, but not limited to, organic and inorganic components in petroleum source rocks, ore and mine waste, clay minerals, and glassy phases. Procedures can be adapted to meet a variety of research objectives.

  1. The Diffraction Response Interpolation Method

    DEFF Research Database (Denmark)

    Jespersen, Søren Kragh; Wilhjelm, Jens Erik; Pedersen, Peder C.

    1998-01-01

    Computer modeling of the output voltage in a pulse-echo system is computationally very demanding, particularly whenconsidering reflector surfaces of arbitrary geometry. A new, efficient computational tool, the diffraction response interpolationmethod (DRIM), for modeling of reflectors in a fluid...... medium, is presented. The DRIM is based on the velocity potential impulseresponse method, adapted to pulse-echo applications by the use of acoustical reciprocity. Specifically, the DRIM operates bydividing the reflector surface into planar elements, finding the diffraction response at the corners...

  2. X-Ray Powder Diffraction with Guinier - Haegg Focusing Cameras

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Allan

    1970-12-15

    The Guinier - Haegg focusing camera is discussed with reference to its use as an instrument for rapid phase analysis. An actual camera and the alignment procedure employed in its setting up are described. The results obtained with the instrument are compared with those obtained with Debye - Scherrer cameras and powder diffractometers. Exposure times of 15 - 30 minutes with compounds of simple structure are roughly one-sixth of those required for Debye - Scherrer patterns. Coupled with the lower background resulting from the use of a monochromatic X-ray beam, the shorter exposure time gives a ten-fold increase in sensitivity for the detection of minor phases as compared with the Debye - Scherrer camera. Attention is paid to the precautions taken to obtain reliable Bragg angles from Guinier - Haegg film measurements, with particular reference to calibration procedures. The evaluation of unit cell parameters from Guinier - Haegg data is discussed together with the application of tests for the presence of angle-dependent systematic errors. It is concluded that with proper calibration procedures and least squares treatment of the data, accuracies of the order of 0.005% are attainable. A compilation of diffraction data for a number of compounds examined in the Active Central Laboratory at Studsvik is presented to exemplify the scope of this type of powder camera.

  3. Acemetacin cocrystal structures by powder X-ray diffraction

    Science.gov (United States)

    Bolla, Geetha

    2017-01-01

    Cocrystals of acemetacin drug (ACM) with nicotinamide (NAM), p-aminobenzoic acid (PABA), valerolactam (VLM) and 2-pyridone (2HP) were prepared by melt crystallization and their X-ray crystal structures determined by high-resolution powder X-ray diffraction. The powerful technique of structure determination from powder data (SDPD) provided details of molecular packing and hydrogen bonding in pharmaceutical cocrystals of acemetacin. ACM–NAM occurs in anhydrate and hydrate forms, whereas the other structures crystallized in a single crystalline form. The carboxylic acid group of ACM forms theacid–amide dimer three-point synthon R 3 2(9)R 2 2(8)R 3 2(9) with three different syn amides (VLM, 2HP and caprolactam). The conformations of the ACM molecule observed in the crystal structures differ mainly in the mutual orientation of chlorobenzene fragment and the neighboring methyl group, being anti (type I) or syn (type II). ACM hydrate, ACM—NAM, ACM–NAM-hydrate and the piperazine salt of ACM exhibit the type I conformation, whereas ACM polymorphs and other cocrystals adopt the ACM type II conformation. Hydrogen-bond interactions in all the crystal structures were quantified by calculating their molecular electrostatic potential (MEP) surfaces. Hirshfeld surface analysis of the cocrystal surfaces shows that about 50% of the contribution is due to a combination of strong and weak O⋯H, N⋯H, Cl⋯H and C⋯H interactions. The physicochemical properties of these cocrystals are under study. PMID:28512568

  4. Acemetacin cocrystal structures by powder X-ray diffraction

    Directory of Open Access Journals (Sweden)

    Geetha Bolla

    2017-05-01

    Full Text Available Cocrystals of acemetacin drug (ACM with nicotinamide (NAM, p-aminobenzoic acid (PABA, valerolactam (VLM and 2-pyridone (2HP were prepared by melt crystallization and their X-ray crystal structures determined by high-resolution powder X-ray diffraction. The powerful technique of structure determination from powder data (SDPD provided details of molecular packing and hydrogen bonding in pharmaceutical cocrystals of acemetacin. ACM–NAM occurs in anhydrate and hydrate forms, whereas the other structures crystallized in a single crystalline form. The carboxylic acid group of ACM forms theacid–amide dimer three-point synthon R32(9R22(8R32(9 with three different syn amides (VLM, 2HP and caprolactam. The conformations of the ACM molecule observed in the crystal structures differ mainly in the mutual orientation of chlorobenzene fragment and the neighboring methyl group, being anti (type I or syn (type II. ACM hydrate, ACM—NAM, ACM–NAM-hydrate and the piperazine salt of ACM exhibit the type I conformation, whereas ACM polymorphs and other cocrystals adopt the ACM type II conformation. Hydrogen-bond interactions in all the crystal structures were quantified by calculating their molecular electrostatic potential (MEP surfaces. Hirshfeld surface analysis of the cocrystal surfaces shows that about 50% of the contribution is due to a combination of strong and weak O...H, N...H, Cl...H and C...H interactions. The physicochemical properties of these cocrystals are under study.

  5. X-Ray Powder Diffraction with Guinier - Haegg Focusing Cameras

    International Nuclear Information System (INIS)

    Brown, Allan

    1970-12-01

    The Guinier - Haegg focusing camera is discussed with reference to its use as an instrument for rapid phase analysis. An actual camera and the alignment procedure employed in its setting up are described. The results obtained with the instrument are compared with those obtained with Debye - Scherrer cameras and powder diffractometers. Exposure times of 15 - 30 minutes with compounds of simple structure are roughly one-sixth of those required for Debye - Scherrer patterns. Coupled with the lower background resulting from the use of a monochromatic X-ray beam, the shorter exposure time gives a ten-fold increase in sensitivity for the detection of minor phases as compared with the Debye - Scherrer camera. Attention is paid to the precautions taken to obtain reliable Bragg angles from Guinier - Haegg film measurements, with particular reference to calibration procedures. The evaluation of unit cell parameters from Guinier - Haegg data is discussed together with the application of tests for the presence of angle-dependent systematic errors. It is concluded that with proper calibration procedures and least squares treatment of the data, accuracies of the order of 0.005% are attainable. A compilation of diffraction data for a number of compounds examined in the Active Central Laboratory at Studsvik is presented to exemplify the scope of this type of powder camera

  6. A sample holder for in-house X-ray powder diffraction studies of protein powders

    DEFF Research Database (Denmark)

    Frankær, Christian Grundahl; Harris, Pernille; Ståhl, Kenny

    2011-01-01

    A sample holder for handling samples of protein for in-house X-ray powder diffraction (XRPD) analysis has been made and tested on lysozyme. The use of an integrated pinhole reduced the background, and good signal-to-noise ratios were obtained from only 7 l of sample, corresponding to approximatel...... 2-3 mg of dry protein. The sample holder is further adaptable to X-ray absorption spectroscopy (XAS) measurements. Both XRPD and XAS at the Zn K-edge were tested with hexameric Zn insulin....

  7. Method of solidifying powderous wastes

    International Nuclear Information System (INIS)

    Kakimoto, Akira; Miyake, Takashi; Sato, Shuichi; Inagaki, Yuzo.

    1985-01-01

    Purpose: To improve the properties of solidification products, in the case of solidifying powderous wastes with thermosetting resins. Method. A solvent for the solution of the thermosetting resin is admixed with the powderous wastes into a paste-like form prior to adding the resin to the wastes, which are then mixed with the resin solution. As the result, those solidification products having the specific gravity and the compression strength more excellent than those of the conventional ones, and much higher than the reference values can be obtained. (Kamimura, M.)

  8. ENDIX. A computer program to simulate energy dispersive X-ray and synchrotron powder diffraction diagrams

    International Nuclear Information System (INIS)

    Hovestreydt, E.; Karlsruhe Univ.; Parthe, E.; Benedict, U.

    1987-01-01

    A Fortran 77 computer program is described which allows the simulation of energy dispersive X-ray and synchrotron powder diffraction diagrams. The input consists of structural data (space group, unit cell dimensions, atomic positional and displacement parameters) and information on the experimental conditions (chosen Bragg angle, type of X-ray tube and applied voltage or operating power of synchrotron radiation source). The output consists of the normalized intensities of the diffraction lines, listed by increasing energy (in keV), and of an optional intensity-energy plot. The intensities are calculated with due consideration of the wave-length dependence of both the anomalous dispersion and the absorption coefficients. For a better agreement between observed and calculated spectra provision is made to optionally superimpose, on the calculated diffraction line spectrum, all additional lines such as fluorescence and emission lines and escape peaks. The different effects which have been considered in the simulation are discussed in some detail. A sample calculation of the energy dispersive powder diffraction pattern of UPt 3 (Ni 3 Sn structure type) is given. Warning: the user of ENDIX should be aware that for a successful application it is necessary to adapt the program to correspond to the actual experimental conditions. Even then, due to the only approximately known values of certain functions, the agreement between observed and calculated intensities will not be as good as for angle dispersive diffraction methods

  9. The structure of denisovite, a fibrous nanocrystalline polytypic disordered `very complex' silicate, studied by a synergistic multi-disciplinary approach employing methods of electron crystallography and X-ray powder diffraction

    Directory of Open Access Journals (Sweden)

    Ira V. Rozhdestvenskaya

    2017-05-01

    Full Text Available Denisovite is a rare mineral occurring as aggregates of fibres typically 200–500 nm diameter. It was confirmed as a new mineral in 1984, but important facts about its chemical formula, lattice parameters, symmetry and structure have remained incompletely known since then. Recently obtained results from studies using microprobe analysis, X-ray powder diffraction (XRPD, electron crystallography, modelling and Rietveld refinement will be reported. The electron crystallography methods include transmission electron microscopy (TEM, selected-area electron diffraction (SAED, high-angle annular dark-field imaging (HAADF, high-resolution transmission electron microscopy (HRTEM, precession electron diffraction (PED and electron diffraction tomography (EDT. A structural model of denisovite was developed from HAADF images and later completed on the basis of quasi-kinematic EDT data by ab initio structure solution using direct methods and least-squares refinement. The model was confirmed by Rietveld refinement. The lattice parameters are a = 31.024 (1, b = 19.554 (1 and c = 7.1441 (5 Å, β = 95.99 (3°, V = 4310.1 (5 Å3 and space group P12/a1. The structure consists of three topologically distinct dreier silicate chains, viz. two xonotlite-like dreier double chains, [Si6O17]10−, and a tubular loop-branched dreier triple chain, [Si12O30]12−. The silicate chains occur between three walls of edge-sharing (Ca,Na octahedra. The chains of silicate tetrahedra and the octahedra walls extend parallel to the z axis and form a layer parallel to (100. Water molecules and K+ cations are located at the centre of the tubular silicate chain. The latter also occupy positions close to the centres of eight-membered rings in the silicate chains. The silicate chains are geometrically constrained by neighbouring octahedra walls and present an ambiguity with respect to their z position along these walls, with displacements between neighbouring layers being

  10. Modelling the X-ray powder diffraction of nitrogen-expanded austenite using the Debye formula

    DEFF Research Database (Denmark)

    Oddershede, Jette; Christiansen, Thomas; Ståhl, Kenny

    2008-01-01

    Stress-free and homogeneous samples of nitrogen-expanded austenite, a defect-rich f.c.c. structure with a high interstitial nitrogen occupancy (between 0.36 and 0.61), have been studied using X-ray powder diffraction and Debye simulations. The simulations confirm the presence of deformation...... to be indistinguishable to X-ray powder diffraction....

  11. High-pressure powder X-ray diffraction at the turn of the century

    International Nuclear Information System (INIS)

    Paszkowicz, W.

    2002-01-01

    Studies at extreme pressures and temperatures are helpful for understanding the physical properties of the solid state, including such classes of materials as semiconductors, superconductors or minerals. This is connected with the opportunity of tuning the pressure by many orders of magnitude. Diamond-anvil and large-anvil pressure cells installed at dedicated synchrotron beamlines are efficient tools for examination of crystal structure, equation of state, compressibility and phase transitions. One of basic methods in such studies is powder diffraction. This review is devoted to methods of powder X-ray diffraction at high-pressures generated by devices installed at synchrotron radiation sources, in particular to the principles of operation of high-pressure-high-temperature cells. General information on high-pressure diffraction facilities installed at 11 synchrotron storage rings in the world is provided. Measurement aspects are considered, including (i) pressure generation and calibration, (ii) strain in the sample, the pressure marker and the pressure-transmitting medium and (iii) pressure and temperature distributions within the cells. Sources of interest in high-pressure diffraction studies (design of new materials, observation of new phenomena, confrontation of theory with experiment) are briefly discussed. Recent developments of high-pressure methods make that pressure becomes a variable playing a key role in investigation of condensed matter. The paper ends with some remarks on the possible future developments of the technique

  12. In situ X-ray powder diffraction, synthesis, and magnetic properties of InVO 3

    Science.gov (United States)

    Lundgren, Rylan J.; Cranswick, Lachlan M. D.; Bieringer, Mario

    2006-12-01

    We report the first synthesis and high-temperature in situ X-ray diffraction study of InVO 3. Polycrystalline InVO 3 has been prepared via reduction of InVO 4 using a carbon monoxide/carbon dioxide buffer gas. InVO 3 crystallizes in the bixbyite structure in space group Ia-3 (206) with a=9.80636(31) Å with In 3+/V 3+ disorder on the (8 b) and (24 d) cation sites. In situ powder X-ray diffraction experiments and thermal gravimetric analysis in a CO/CO 2 buffer gas revealed the existence of the metastable phase InVO 3. Bulk samples with 98.5(2)% purity were prepared using low-temperature reduction methods. The preparative methods limited the crystallinity of this new phase to approximately 225(50) Å. Magnetic susceptibility and neutron diffraction experiments suggest a spin-glass ground state for InVO 3.

  13. High throughput screening of ligand binding to macromolecules using high resolution powder diffraction

    Science.gov (United States)

    Von Dreele, Robert B.; D'Amico, Kevin

    2006-10-31

    A process is provided for the high throughput screening of binding of ligands to macromolecules using high resolution powder diffraction data including producing a first sample slurry of a selected polycrystalline macromolecule material and a solvent, producing a second sample slurry of a selected polycrystalline macromolecule material, one or more ligands and the solvent, obtaining a high resolution powder diffraction pattern on each of said first sample slurry and the second sample slurry, and, comparing the high resolution powder diffraction pattern of the first sample slurry and the high resolution powder diffraction pattern of the second sample slurry whereby a difference in the high resolution powder diffraction patterns of the first sample slurry and the second sample slurry provides a positive indication for the formation of a complex between the selected polycrystalline macromolecule material and at least one of the one or more ligands.

  14. Multipole electron-density modelling of synchrotron powder diffraction data: the case of diamond

    DEFF Research Database (Denmark)

    Svendsen, H.; Overgaard, J.; Busselez, R.

    2010-01-01

    between experiment and theory, and the study therefore demonstrates that synchrotron powder diffraction can indeed provide accurate structure-factor values based on data measured in minutes with limited sample preparation. Thus, potential systematic errors such as extinction and twinning commonly......Accurate structure factors are extracted from synchrotron powder diffraction data measured on crystalline diamond based on a novel multipole model division of overlapping reflection intensities. The approach limits the spherical-atom bias in structure factors extracted from overlapping powder data...

  15. Structural characterisation of 1- and 2-dimensional transition metal polymers using powder neutron diffraction

    International Nuclear Information System (INIS)

    James, M.

    1999-01-01

    Powder neutron diffraction provides an alternate technique for the structural study of transition metal polymers and finds utility over standard X-ray methods in two significant ways. Firstly, due to a different instrument geometry, preferred orientation effects are removed from the system. The second advantage gained by utilising neutrons is that H atoms in the sample contribute much more to the nuclear scattering of the diffraction profile - allowing their atomic position to be accurately determined. In X-ray diffraction studies, where H atoms typically account for only ∼3-5% of the scattering from the sample, it is essentially impossible to refine their position in the molecular structure. The structures of several transition metal polymers have been determined using neutrons from the HIFAR reactor at ANSTO and the Powder Diffractometers HRPD and MRPD, along with Rietveld refinement methods. The 1-dimensional polymer dibromobis(thiazole)nickel(II) illustrated in the paper is characteristic of these types of systems which are comprised of transition metal centres bridged by halogen atoms with pendant amine side groups

  16. Rietveld refinement with time-of-flight powder diffraction data from pulsed neutron sources

    International Nuclear Information System (INIS)

    David, W.I.F.; Jorgensen, J.D.

    1990-10-01

    The recent development of accelerator-based pulsed neutron sources has led to the widespread use of the time-of-flight technique for neutron powder diffraction. The properties of the pulsed source make possible unusually high resolution over a wide range of d spacings, high count rates, and the ability to collect complete data at fixed scattering angles. The peak shape and other instrument characteristics can be accurately modelled, which make Rietveld refinement possible for complex structures. In this paper we briefly review the development of the Rietveld method for time-of-flight diffraction data from pulsed neutron sources and discuss the latest developments in high resolution instrumentation and advanced Rietveld analysis methods. 50 refs., 12 figs., 14 tabs

  17. X-ray powder diffraction analysis of liquid-phase-sintered silicon carbide ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz, A.L.; Sanchez-Bajo, F. [Universidad de Extremadura, Badajoz (Spain). Dept. de Electronica e Ingenieria Electromecanica; Cumbrera, F.L. [Universidad de Extremadura, Badajoz (Spain). Dept. de Fisica

    2002-07-01

    In an attempt to gain a comprehensive understanding of the microstructural evolution in liquid-phase-sintered silicon carbide ceramics, the effect of the starting {beta}-SiC powder has been studied. Pellets of two different {beta}-SiC starting powders were sintered with simultaneous additions of Al{sub 2}O{sub 3} and Y{sub 2}O{sub 3} at 1950 C for 1 hour in flowing argon atmosphere. Here we have used X-ray diffraction to obtain the relative abundance of the resulting SiC polytypes after sintering. The significant influence of the defects concentration on the {beta} to {alpha} transformation rate has been determined using the Rietveld method. (orig.)

  18. Extending the reach of powder diffraction modelling by user defined macros

    CERN Document Server

    Scardi, Paolo

    2010-01-01

    The main focus of this special topic volume is the development and possibilities of the MACRO language within TOPAS, with a specific session dedicated to WPPM. The collection is presented here in the form of a ""macro tutorial"" for the benefit of the entire powder diffraction community. More than a collection of standard scientific papers, the contributions to this special issue provide methods, tutorials and practical suggestions and solutions for the proper use of TOPAS and WPPM in a number of applications; ranging from the most common to the most refined and specific cases.Readers will fin

  19. Monitoring protein precipitates by in-house X-ray powder diffraction

    DEFF Research Database (Denmark)

    Ståhl, Kenny; Frankær, Christian Grundahl; Petersen, Jakob

    2013-01-01

    of such calculated powder patterns from insulin and lysozyme have been included in the powder diffraction database and successfully used for search-match identification. However, the fit could be much improved if peak asymmetry and multiple bulk-solvent corrections were included. When including a large number...

  20. Qualitative analysis of powder x-ray diffraction data

    International Nuclear Information System (INIS)

    Raftery, T.

    1999-01-01

    Full text: The main task of qualitative analysis is the determination of the presence of major, minor and if practical trace phases in a sample. The attainment of this goal is dependent on the quality of alignment (line position and intensity) as well as quality of sample preparation. Identification is generally on the basis of structure and dependent on the use of reference patterns. There are inherent limitations to the use of reference patterns including lack of reference patterns for the phase of interest (rare), solid solutions or substitutions (likely) and poor quality of reference patterns (unusual). With multiphase samples, there are the added problems of line overlap or interference, determining minor or trace phases in the presence of major phases, the decrease of intensity with concentration and influence of mass absorption on intensities. Within multiphase samples there may be many phases, some of which are in low abundance. It is sometimes possible (and usually desirable) to fractionate the sample by some physical or chemical method (while attempting not to create new phases as a result). It is usually important and often critical to have available supplementary information about the sample - either chemical or physical, or a history of preparation or formation. A central issue is what constitutes a match. A match is an adequate accounting of the distribution of intensity in the diffraction pattern. The match can be thought of in terms of a sum of δ2θ (or δd/d) and/or δI/I ref , and the consistency with known information. The calculated measures give rise to the figures of merit (FOM) of search match programs. It must always be remembered that two compounds of the same space group and similar cell parameters (eg. FCC metals) are going to have very similar diffraction patterns - any search/match technique usually arrives at a stage where there is a list of possibilities that must be decided between. The range search-match techniques span manual

  1. Structure solution from powder neutron and x-ray diffraction data: getting the best of both worlds

    International Nuclear Information System (INIS)

    Hunter, B.A.

    2000-01-01

    Full text: Powder diffraction methods have traditionally been used in three main areas: phase identification and quantification, lattice parameter determination and structure refinement. Until recently structure solution has been the almost exclusive domain of single crystal diffraction methods, predominantly using x-rays. The increasing use of synchrotron and neutron sources, and the unrelenting advances in computing hardware and software means that powder methods are challenging single crystal methods as a practical method for structure solution, especially when single crystal method can not be applied. It is known that structural refinements from a known starting structure using combined X-ray and neutron data sets are capable of providing highly accurate structures. Likewise, using combined x-ray and neutron powder diffraction data in the structure solution process should also be a powerful technique, although to date no one is pursuing this methodology. This paper present examples of solutions to the problem. Namely we are using high resolution powder X-ray and neutron methods to solve the structures of molecular materials and minerals, then refining the structures using both sets of data. In this way we exploit the advantages of both methods while minimising the disadvantages. We present our solution for a small amino acid structure, a metalorganic and a mineral structure

  2. Absolute determination by X-ray diffraction of a binary or ternary mixture: nickel oxide and fluoride in a nickel powder (1960)

    International Nuclear Information System (INIS)

    Charpin, P.; Hauptman, A.

    1960-01-01

    The method employed is based upon the comparison between computed and measured intensities for conveniently selected X-Ray diffraction lines of each component of the powder. Care must be taken to allow for absorption, both inside each grain and in overall sample. This method has been applied to the determination of nickel oxide and fluoride in a nickel powder. (author) [fr

  3. X-ray powder diffraction in forensic practice

    Czech Academy of Sciences Publication Activity Database

    Kotrlý, M.; Bezdička, Petr

    2006-01-01

    Roč. 13, č. 3 (2006), s. 153-155 ISSN 1210-8529 R&D Projects: GA MV RN20052005001 Institutional research plan: CEZ:AV0Z40320502 Keywords : X-ray powder microdiffraction * pigments * forensic practice Subject RIV: CA - Inorganic Chemistry

  4. A wavelet transform algorithm for peak detection and application to powder x-ray diffraction data.

    Science.gov (United States)

    Gregoire, John M; Dale, Darren; van Dover, R Bruce

    2011-01-01

    Peak detection is ubiquitous in the analysis of spectral data. While many noise-filtering algorithms and peak identification algorithms have been developed, recent work [P. Du, W. Kibbe, and S. Lin, Bioinformatics 22, 2059 (2006); A. Wee, D. Grayden, Y. Zhu, K. Petkovic-Duran, and D. Smith, Electrophoresis 29, 4215 (2008)] has demonstrated that both of these tasks are efficiently performed through analysis of the wavelet transform of the data. In this paper, we present a wavelet-based peak detection algorithm with user-defined parameters that can be readily applied to the application of any spectral data. Particular attention is given to the algorithm's resolution of overlapping peaks. The algorithm is implemented for the analysis of powder diffraction data, and successful detection of Bragg peaks is demonstrated for both low signal-to-noise data from theta-theta diffraction of nanoparticles and combinatorial x-ray diffraction data from a composition spread thin film. These datasets have different types of background signals which are effectively removed in the wavelet-based method, and the results demonstrate that the algorithm provides a robust method for automated peak detection.

  5. About some practical aspects of X-ray diffraction : From powder to thin film

    Energy Technology Data Exchange (ETDEWEB)

    Valvoda, V [Charles Univ. Prague (Czech Republic). Faculty of Mathematics and Physics

    1996-09-01

    Structure of thin films can be amorphous, polycrystalline or epitaxial, and the films can be prepared as a single layer films, multilayers or as graded films. A complete structure analysis of thin films by means of X-ray diffraction (XRD) usually needs more than one diffraction geometry to be used. Their principles, advantages and disadvantages will be shortly described, especially with respect to their different sampling depth and different response to orientation of diffracting crystallographic planes. Main differences in structure of thin films with respect to powder samples are given by a singular direction of their growth, by their adhesion to a substrate and often also by a simultaneous bombardment by atomic species during the growth. It means that a thermodynamically unstable atomic structures can be found too. These special features of growth of thin polycrystalline films are reflected in often found strong preferred orientation of grains and in residual stresses conserved in the films. The methods of structure analysis of thin films by XRD will be compared with other techniques which can supply structure images on different scales.

  6. Vibrational spectra, powder X-ray diffractions and physical properties of cyanide complexes with 1-ethylimidazole

    Science.gov (United States)

    Kürkçüoğlu, Güneş Süheyla; Kiraz, Fulya Çetinkaya; Sayın, Elvan

    2015-10-01

    The heteronuclear tetracyanonickelate(II) complexes of the type [M(etim)Ni(CN)4]n (hereafter, abbreviated as M-Ni-etim, M = Mn(II), Fe(II) or Co(II); etim = 1-ethylimidazole, C5H8N2) were prepared in powder form and characterized by FT-IR and Raman spectroscopy, powder X-ray diffraction (PXRD), thermal (TG; DTG and DTA), and elemental analysis techniques. The structures of these complexes were elucidated using vibrational spectra and powder X-ray diffraction patterns with the peak assignment to provide a better understanding of the structures. It is shown that the spectra are consistent with a proposed crystal structure for these compounds derived from powder X-ray diffraction measurements. Vibrational spectra of the complexes were presented and discussed with respect to the internal modes of both the etim and the cyanide ligands. The C, H and N analyses were carried out for all the complexes. Thermal behaviors of these complexes were followed using TG, DTG and DTA curves in the temperature range 30-700 °C in the static air atmosphere. The FT-IR, Raman spectra, thermal and powder X-ray analyses revealed no significant differences between the single crystal and powder forms. Additionally, electrical and magnetic properties of the complexes were investigated. The FT-IR and Raman spectroscopy, PXRD, thermal and elemental analyses results propose that these complexes are similar in structure to the Hofmann-type complexes.

  7. Beamline I11 at Diamond: a new instrument for high resolution powder diffraction.

    Science.gov (United States)

    Thompson, S P; Parker, J E; Potter, J; Hill, T P; Birt, A; Cobb, T M; Yuan, F; Tang, C C

    2009-07-01

    The performance characteristics of a new synchrotron x-ray powder diffraction beamline (I11) at the Diamond Light Source are presented. Using an in-vacuum undulator for photon production and deploying simple x-ray optics centered around a double-crystal monochromator and a pair of harmonic rejection mirrors, a high brightness and low bandpass x-ray beam is delivered at the sample. To provide fast data collection, 45 Si(111) analyzing crystals and detectors are installed onto a large and high precision diffractometer. High resolution powder diffraction data from standard reference materials of Si, alpha-quartz, and LaB6 are used to characterize instrumental performance.

  8. ZDS - a computer program for analysis of X-ray powder diffraction patterns

    International Nuclear Information System (INIS)

    Ondrus, P.

    1993-01-01

    The ZDS system creates an integrated environment of procedures for complete and precise analysis of raw powder diffraction patterns. The basis of the ZDS system is a graphic control centre for easy and user-friendly application of all included procedures. It offers a number of application procedures without an interaction with any data base. The program operates either in an automatic or manual mode. The manual mode makes possible specialized applications. The input and output of the data are compatible with Philips and Siemens powder diffraction software. The ZDS system runs with Intel 80286 or 80386-based PC computers with or without math-coprocesor. (orig.)

  9. Crystal structure determination from powder diffraction data of the coumarin vanillin chalcone

    Czech Academy of Sciences Publication Activity Database

    Ghouili, A.; Rohlíček, Jan; Ayed, T.B.; Hassen, R.B.

    2014-01-01

    Roč. 29, č. 4 (2014), s. 361-365 ISSN 0885-7156 Grant - others:AV ČR(CZ) Praemium Academiae Institutional support: RVO:68378271 Keywords : chalcone * absorption spectra * powder diffraction * crystal structure determination * coumarin derivatives Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.636, year: 2014

  10. Dihydroxycoumarin Schiff base synthesis and structure determination from powder diffraction data

    Czech Academy of Sciences Publication Activity Database

    Rohlíček, Jan; Ketata, I.; Ben Ayed, T.; Ben Hassen, R.

    2013-01-01

    Roč. 1051, NOV (2013), s. 280-284 ISSN 0022-2860 Grant - others:AV ČR(CZ) AP0701 Program:Akademická prémie - Praemium Academiae Institutional support: RVO:68378271 Keywords : powder diffraction * structure solution * Schiff base * dihydroxycoumarine Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.599, year: 2013

  11. Proceedings of the 1986 workshop on advanced time-of-flight neutron powder diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Lawson, A.C.; Smith, K. (comps.)

    1986-09-01

    This report contains abstracts of talks and summaries of discussions from a small workshop held to discuss the future of time-of-flight neutron powder diffraction and its implementation at the Los Alamos Neutron Scattering Center. 47 refs., 3 figs.

  12. Proceedings of the 1986 workshop on advanced time-of-flight neutron powder diffraction

    International Nuclear Information System (INIS)

    Lawson, A.C.; Smith, K.

    1986-09-01

    This report contains abstracts of talks and summaries of discussions from a small workshop held to discuss the future of time-of-flight neutron powder diffraction and its implementation at the Los Alamos Neutron Scattering Center. 47 refs., 3 figs

  13. Application of the ellipsoid modeling of the average shape of nanosized crystallites in powder diffraction

    DEFF Research Database (Denmark)

    Katerinopoulou, Anna; Balic Zunic, Tonci; Lundegaard, Lars Fahl

    2012-01-01

    Anisotropic broadening correction in X-ray powder diffraction by an ellipsoidal formula is applied on samples with nanosized crystals. Two cases of minerals with largely anisotropic crystallite shapes are presented. The properly applied formalism not only improves the fitting of the theoretical...

  14. Soft x-ray resonant magnetic powder diffraction on PrNiO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Staub, U [Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); GarcIa-Fernandez, M [Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); Mulders, A M [Department of Applied Physics, Curtin University of Technology, GPO Box U1987, Perth WA 6845 (Australia); Bodenthin, Y [Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); MartInez-Lope, M J [Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, E-28049 Madrid (Spain); Alonso, J A [Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, E-28049 Madrid (Spain)

    2007-03-07

    We report on the first soft x-ray resonant powder diffraction experiments performed at the Ni L{sub 2,3} edges of PrNiO{sub 3}. The temperature, polarization and energy dependence of the (1/2 0 1/2) reflection indicates a magnetic origin for the signal. This experiment demonstrates that x-ray resonant magnetic powder diffraction can be relatively easily performed in the soft x-ray regime due to the very large enhancement factors at the absorption edges. Such experiments allow us to extract important information on the electronic states of the d shell. Similar results can be anticipated from orbital reflections measured in a powder. (fast track communication)

  15. The IPNS rietveld analysis software package for TOF [time-of-flight] powder diffraction data: Recent developments

    International Nuclear Information System (INIS)

    Rotella, F.J.; Richardson, J.W. Jr.

    1987-01-01

    A system of FORTRAN programs for the analysis of time-of-flight (TOF) neutron powder diffraction data via the Rietveld method at IPNS has been modified recently, making it possible to analyze data that exhibit diffraction maxima broadened due to anisotropic strain and that can be modeled by individual atomic anharmonic thermal vibrations. The observation of noncrystalline scattering in data from some powder samples has led to the development of software to fit such scattering by a function related to a radial distribution function through Fourier-filtering techniques. The ''user friendliness'' of the IPNS Rietveld package has been enhanced by the development of ''RIETVELD,'' a menu-based VAX/VMS command language routine for interactive file manipulation and program execution

  16. Ab initio structure determination via powder X-ray diffraction

    Indian Academy of Sciences (India)

    Unknown

    Although the method of structure completion when once the starting model is provided is ... In this article a survey of the recent development in this area is ..... The Monte Carlo method 4,9 differs from the traditional approaches as it operates in.

  17. Powder X-ray diffraction studies of structural and kinetic aspects of polymorphism

    International Nuclear Information System (INIS)

    Chan, F.C.

    1999-01-01

    Polymorphism is a poorly understood phenomenon that is of considerable technological interest to the pharmaceutical industry. The polymorph selected can influence the bioavailability, processing and stability of the pharmaceutical dosage form. In this study structural, kinetic and thermodynamics aspects of polymorphism and polymorphic phase transformations have been examined using powder X-ray diffraction (PXRD). The compound sulphathiazole is a well-studied model in the investigation of polymorphism and crystal growth. There are five known polymorphic forms and the structure of form V was unknown until this study. The difficulty has been that it has not been possibly to prepare crystals of appropriate size and quality for single crystal diffraction. Furthermore, structure solution from powder data for organic molecules is almost impossible. Despite the challenge the structure of sulphathiazole form V have been solved ab initio from powder data using direct methods. With 16 non-hydrogen atoms in the molecule and two molecules in the asymmetric unit, this structure represents a significant advance in terms of the complexity of an organic structure solved from PXRD data. The structural data should be invaluable for rationalizing experimental observations and the development of theoretical ideas regarding polymorphism and crystal growth. The second part of the study, has examined kinetics of polymorphic phase transformations as a function of pressure combined with temperature using real-time synchrotron PXRD. The significance of pressure arises from the fact that phase transitions can be induced in pharmaceuticals during tabletting. The phase transformation behaviour of rubidium iodide (chosen as a simple test model) has been investigated as a function of isobaric pressure at ambient and elevated temperatures. The kinetics have been characterized by using the Johnson-Melil-Avrami equation. The effect of successive cycling across the transition pressure was also

  18. X-ray filter for x-ray powder diffraction

    Science.gov (United States)

    Sinsheimer, John Jay; Conley, Raymond P.; Bouet, Nathalie C. D.; Dooryhee, Eric; Ghose, Sanjit

    2018-01-23

    Technologies are described for apparatus, methods and systems effective for filtering. The filters may comprise a first plate. The first plate may include an x-ray absorbing material and walls defining first slits. The first slits may include arc shaped openings through the first plate. The walls of the first plate may be configured to absorb at least some of first x-rays when the first x-rays are incident on the x-ray absorbing material, and to output second x-rays. The filters may comprise a second plate spaced from the first plate. The second plate may include the x-ray absorbing material and walls defining second slits. The second slits may include arc shaped openings through the second plate. The walls of the second plate may be configured to absorb at least some of second x-rays and to output third x-rays.

  19. Crystal structure refinement of α-Si3N4 using synchrotron radiation powder diffraction data: unbiased refinement strategy

    International Nuclear Information System (INIS)

    Toraya, H.

    2000-01-01

    The crystal structure of α-silicon nitride (Si 3 N 4 ) was refined by the Rietveld method using synchrotron radiation powder diffraction data (wavelength = 1.2 A) collected at station BL-4B2 in the photon factory. A refinement procedure that adopted a new weight function, w = 1/Y o e (Y o is the observed profile intensity and e ≅ 2), for the least-squares fitting [Toraya (1998). J. Appl. Cryst. 31, 333-343] was studied. The most reasonable structural parameters were obtained with e = 1.7. Crystal data of α-Si 3 N 4 : trigonal, P31c, a = 7.75193 (3), c = 5.61949 (4) A, V = 292.447 (3) A 3 , Z = 4; R p = 5.08, R wp = 6.50, R B = 3.36, R F = 2.26%. The following five factors are considered equally important for deriving accurate structural parameters from powder diffraction data: (i) sufficiently large sin θ/λ range of >0.8 A -1 ; (ii) adequate counting statistics; (iii) correct profile model; (iv) proper weighting on observations to give a uniform distribution of the mean weighted squared residuals; (v) high-angular-resolution powder diffraction data. (orig.)

  20. Synthesis and sintering of nanocrystalline hydroxyapatite powders by citric acid sol-gel combustion method

    International Nuclear Information System (INIS)

    Han Yingchao; Li Shipu; Wang Xinyu; Chen Xiaoming

    2004-01-01

    The citric acid sol-gel combustion method has been used for the synthesis of nanocrystalline hydroxyapatite (HAP) powder from calcium nitrate, diammonium hydrogen phosphate and citric acid. The phase composition of HAP powder was characterized by X-ray powder diffraction analysis (XRD). The morphology of HAP powder was observed by transmission electron microscope (TEM). The HAP powder has been sintered into microporous ceramic in air at 1200 deg. C with 3 h soaking time. The microstructure and phase composition of the resulting HAP ceramic were characterized by scanning electron microscope (SEM) and XRD, respectively. The physical characterization of open porosity and flexural strength have also been carried out

  1. Validation of powder X-ray diffraction following EN ISO/IEC 17025.

    Science.gov (United States)

    Eckardt, Regina; Krupicka, Erik; Hofmeister, Wolfgang

    2012-05-01

    Powder X-ray diffraction (PXRD) is used widely in forensic science laboratories with the main focus of qualitative phase identification. Little is found in literature referring to the topic of validation of PXRD in the field of forensic sciences. According to EN ISO/IEC 17025, the method has to be tested for several parameters. Trueness, specificity, and selectivity of PXRD were tested using certified reference materials or a combination thereof. All three tested parameters showed the secure performance of the method. Sample preparation errors were simulated to evaluate the robustness of the method. These errors were either easily detected by the operator or nonsignificant for phase identification. In case of the detection limit, a statistical evaluation of the signal-to-noise ratio showed that a peak criterion of three sigma is inadequate and recommendations for a more realistic peak criterion are given. Finally, the results of an international proficiency test showed the secure performance of PXRD. © 2012 American Academy of Forensic Sciences.

  2. Calculated powder x-ray diffraction data for three tantalum tungstates

    International Nuclear Information System (INIS)

    Holcombe, C.E. Jr.

    1976-11-01

    A study was made of computer-simulated powder x-ray diffraction data for Ta 22 W 4 O 67 , Ta 2 WO 8 , and Ta 16 W 18 O 94 --the three compounds in the Ta 2 O 5 --WO 3 system from 27 to 69 mole percent WO 3 . The crystal structures of Ta 2 WO 8 and one form of Ta 16 W 18 O 94 (Type B) were deduced from reported data. 8 tables

  3. Neutron powder diffraction studies of Hydrogen and Denterium in Palladium Phosphides

    International Nuclear Information System (INIS)

    Andersson, Y.

    1986-01-01

    The use of the Rietveld-type profile refinements on neutron powder diffraction intensity data for determining crystallographic positions of hydrogen and deuterium in metal hydrides is illustrated by results obtained on some hydrogenated and deuterated palladium phosphides. The structural features of the solid solutions of hydrogen and deuterium in Pd/sb15/P/sb2/ Pd/sb6/P and Pd/sb3/P/sb1-u/ (0< u<0.28) are briefly presented and discussed

  4. A high-resolution neutron powder diffraction study of neodymium doping in barium cerate

    DEFF Research Database (Denmark)

    Knight, K.S.; Bonanos, N.

    1995-01-01

    High-resolution neutron powder diffraction data have been collected on 6 perovskites of composition BaCe1-xNdxO3-x/(2), with 0 less than or equal to x less than or equal to 0.2, in which structural phase transitions Pmcn-->P4/mbm at x=0.05, and P4/mbm-->Pm3m at x=0.1, were inferred from a recent ...

  5. High-pressure powder x-ray diffraction experiments on Zn at low temperature

    CERN Document Server

    Takemura, K; Fujihisa, H; Kikegawa, T

    2002-01-01

    High-pressure powder x-ray diffraction experiments have been performed on Zn with a He-pressure medium at low temperature. When the sample was compressed in the He medium at low temperature, large nonhydrostaticity developed, yielding erroneous lattice parameters. On the other hand, when the pressure was changed at high temperatures, good hydrostaticity was maintained. No anomaly in the volume dependence of the c/a axial ratio has been found.

  6. Development of MnBi permanent magnet: Neutron diffraction of MnBi powder

    Energy Technology Data Exchange (ETDEWEB)

    Cui, J., E-mail: jun.cui@pnnl.gov; Choi, J. P.; Li, G.; Polikarpov, E.; Darsell, J. [Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, Washington 99354 (United States); Kramer, M. J.; Zarkevich, N. A.; Wang, L. L.; Johnson, D. D. [Materials Sciences and Engineering Division, Ames Laboratory, Ames, Iowa 50011 (United States); Marinescu, M. [Electron Energy Corporation, Landisville, Pennsylvania 17538 (United States); Huang, Q. Z.; Wu, H. [NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-6102 (United States); Vuong, N. V.; Liu, J. P. [Department of Physics, University of Texas at Arlington, Arlington, Texas 76019 (United States)

    2014-05-07

    MnBi attracts great attention in recent years for its great potential as permanent magnet materials. MnBi phase is difficult to obtain because of the rather drastic peritectic reaction between Mn and Bi. In this paper, we report our effort on synthesizing high purity MnBi compound using conventional powder metallurgical approaches. Neutron diffraction was carried out to investigate the crystal and nuclear structure of the obtained powder. The result shows that the purity of the obtained powder is about 91 wt. % at 300 K, and the magnetic moment of the Mn atom in MnBi lattice is 4.424 and 4.013 μ{sub B} at 50 K and 300 K, respectively.

  7. Development of MnBi permanent magnet: Neutron diffraction of MnBi powder

    Energy Technology Data Exchange (ETDEWEB)

    Cui, J; Choi, JP; Li, G; Polikarpov, E; Darsell, J; Kramer, MJ; Zarkevich, NA; Wang, LL; Johnson, DD; Marinescu, M; Huang, QZ; Wu, H; Vuong, NV; Liu, JP

    2014-05-07

    MnBi attracts great attention in recent years for its great potential as permanent magnet materials. MnBi phase is difficult to obtain because of the rather drastic peritectic reaction between Mn and Bi. In this paper, we report our effort on synthesizing high purity MnBi compound using conventional powder metallurgical approaches. Neutron diffraction was carried out to investigate the crystal and nuclear structure of the obtained powder. The result shows that the purity of the obtained powder is about 91 wt. % at 300 K, and the magnetic moment of the Mn atom in MnBi lattice is 4.424 and 4.013 mu(B) at 50 K and 300 K, respectively. (C) 2014 AIP Publishing LLC.

  8. Advances in X-ray powder diffraction profile analysis and its application in ceramic material studies

    International Nuclear Information System (INIS)

    Zhang, Y.

    1988-01-01

    This dissertation is concerned with the following major aspects: (1) the development of necessary computer codes to carry out X-ray powder diffraction profile analysis (XPDPA) calculations; (2) the establishment of a general reference material (GRM) which greatly extends the application of XPDPA and the study of the application of the GRM in profile analysis; (3) the determination of the coherent diffracting domain size and the lattice residual microstrain for some shock-modified and jet-milled materials. A computer code for diffraction profile refinement, XRAYL, fits a diffraction profile with any one of five mathematical functions, either as symmetric or asymmetric (split mode) forms. The resulting patterns meet the requirements for successful profile analysis of microstrain and crystallite size. Powder diffraction profile analysis requires an instrument calibration standard to correct data for instrumental profiles due to the system optics. A general reference material, LaB 6 , has been established. The pattern of this LaB 6 powder can be used to generate a reference pattern for any other substance. Through three applications, it has been shown that this LaB 6 sample can be used to remove the instrumental broadenings and gives reasonable size and strain estimates in the profile analysis of other materials. Many previous studies have shown that the solid state reactivity and physical properties of some ceramic materials can be substantially enhanced. XPDPA techniques have been used to study the plastic deformation and the reduction of crystallite size for eight shock-modified ceramic materials. The size and strain values of these materials are correlated with shock parameters

  9. submitter Digital Image Correlation of 2D X-ray Powder Diffraction Data for Lattice Strain Evaluation

    CERN Document Server

    Zhang, Hongjia; Salvati, Enrico; Daisenberger, Dominik; Lunt, Alexander J G; Fong, Kai Soon; Song, Xu; Korsunsky, Alexander M

    2018-01-01

    High energy 2D X-ray powder diffraction experiments are widely used for lattice strain measurement. The 2D to 1D conversion of diffraction patterns is a necessary step used to prepare the data for full pattern refinement, but is inefficient when only peak centre position information is required for lattice strain evaluation. The multi-step conversion process is likely to lead to increased errors associated with the ‘caking’ (radial binning) or fitting procedures. A new method is proposed here that relies on direct Digital Image Correlation analysis of 2D X-ray powder diffraction patterns (XRD-DIC, for short). As an example of using XRD-DIC, residual strain values along the central line in a Mg AZ31B alloy bar after 3-point bending are calculated by using both XRD-DIC and the conventional ‘caking’ with fitting procedures. Comparison of the results for strain values in different azimuthal angles demonstrates excellent agreement between the two methods. The principal strains and directions are calculated...

  10. Thermal analysis, X-ray powder diffraction and electron microscopy data related with the production of 1:1 Caffeine:Glutaric Acid cocrystals

    Directory of Open Access Journals (Sweden)

    Íris Duarte

    2016-09-01

    Full Text Available The data presented in this article are related to the production of 1:1 Caffeine:Glutaric Acid cocrystals as part of the research article entitled “Green production of cocrystals using a new solvent-free approach by spray congealing” (Duarte et al., 2016 [1]. More specifically, here we present the thermal analysis and the X-ray powder diffraction data for pure Glutaric Acid, used as a raw material in [1]. We also include the X-ray powder diffraction and electron microscopy data obtained for the 1:1 Caffeine:Glutaric Acid cocrystal (form II produced using the cooling crystallization method reported in “Operating Regions in Cooling Cocrystallization of Caffeine and Glutaric Acid in Acetonitrile” (Yu et al., 2010 [2]. Lastly, we show the X-ray powder diffraction data obtained for assessing the purity of the 1:1 Caffeine:Glutaric cocrystals produced in [1].

  11. Determination of the structure factors of a LiF powder sample by the energy dispersive x-ray diffraction

    International Nuclear Information System (INIS)

    Uno, R.; Ahtee, A.; Paakkari, T.

    1977-01-01

    The structure factors of a LiF powder sample were determined by energy dispersive x-ray diffraction in the range 9 to 25 keV, with the use of a Si(Li) solid state detector, following the method applied on GaP. Since the absorption coefficient of LiF is small at high energy, a fraction of the incident x-rays penetrates through the sample and does not contribute to the diffraction. This effect was taken into account in the determination of the structure factors. Then the structure factors generally agree, within the limit of 5 % error, with those obtained by the usual angle dispersive method, if the penetrated part of the incident beam is less than 40 %. (author)

  12. Crystal structure and tautomerism of Pigment Yellow 138 determined by X-ray powder diffraction and solid-state NMR

    DEFF Research Database (Denmark)

    Gumbert, Silke D.; Körbitzer, Meike; Alig, Edith

    2016-01-01

    The crystal structure of C.I. Pigment Yellow 138 was determined from X-ray powder diffraction data using real-space methods with subsequent Rietveld refinements. The tautomeric state was investigated by solid-state 1D and 2D multinuclear NMR experiments. In the crystals, the compound exhibits...... the NH-tautomer with a hydrogen atom situated at the nitrogen of the quinoline moiety. Direct evidence of the presence of the NH-tautomer is provided by 1H–14N HMQC solid-state NMR at very fast MAS. Solid-state dispersion-corrected density functional theory calculations with BLYP-D3 confirm...

  13. Hybrid Powder - Single Crystal X-Ray Diffraction Instrument for Planetary Mineralogical Analysis of Unprepared Samples, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to develop a planetary exploration XRD/XRF instrument based on a hybrid diffraction approach that complements powder XRD analysis, similar to that of the...

  14. A new parallel and GPU version of a TREOR-based algorithm for indexing powder diffraction data

    Czech Academy of Sciences Publication Activity Database

    Šimeček, I.; Rohlíček, Jan; Zahradnický, T.; Langr, D.

    2015-01-01

    Roč. 48, Feb (2015), 166-170 ISSN 0021-8898 Institutional support: RVO:68378271 Keywords : indexing powder diffraction * TREOR algorithm * GPGPU Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.720, year: 2014

  15. Fast X-ray powder diffraction on I11 at Diamond.

    Science.gov (United States)

    Thompson, Stephen P; Parker, Julia E; Marchal, Julien; Potter, Jonathan; Birt, Adrian; Yuan, Fajin; Fearn, Richard D; Lennie, Alistair R; Street, Steven R; Tang, Chiu C

    2011-07-01

    The commissioning and performance characterization of a position-sensitive detector designed for fast X-ray powder diffraction experiments on beamline I11 at Diamond Light Source are described. The detecting elements comprise 18 detector-readout modules of MYTHEN-II silicon strip technology tiled to provide 90° coverage in 2θ. The modules are located in a rigid housing custom designed at Diamond with control of the device fully integrated into the beamline data acquisition environment. The detector is mounted on the I11 three-circle powder diffractometer to provide an intrinsic resolution of Δ2θ approximately equal to 0.004°. The results of commissioning and performance measurements using reference samples (Si and AgI) are presented, along with new results from scientific experiments selected to demonstrate the suitability of this facility for powder diffraction experiments where conventional angle scanning is too slow to capture rapid structural changes. The real-time dehydrogenation of MgH(2), a potential hydrogen storage compound, is investigated along with ultrafast high-throughput measurements to determine the crystallite quality of different samples of the metastable carbonate phase vaterite (CaCO(3)) precipitated and stabilized in the presence of amino acid molecules in a biomimetic synthesis process.

  16. In situ observation and neutron diffraction of NiTi powder sintering

    International Nuclear Information System (INIS)

    Chen, Gang; Liss, Klaus-Dieter; Cao, Peng

    2014-01-01

    This study investigated NiTi powder sintering behaviour from elemental powder mixtures of Ni/Ti and Ni/TiH 2 using in situ neutron diffraction and in situ scanning electron microscopy. The sintered porous alloys have open porosities ranging from 2.7% to 36.0%. In comparison to the Ni/Ti compact, dehydrogenation occurring in the Ni/TiH 2 compact leads to less densification yet higher chemical homogenization only after high-temperature sintering. For the first time, direct evidence of the eutectoid phase transformation of NiTi at 620 °C is reported by in situ neutron diffraction. A comparative study of cyclic stress–strain behaviours of the porous NiTi alloys made from Ni/Ti and Ni/TiH 2 compacts indicate that the samples sintered from the Ni/TiH 2 compact exhibited a much higher porosity, larger pore size, lower fracture strength, lower close-to-overall porosity ratio and lower Young’s modulus. Instead of enhanced densification by the use of TiH 2 as reported in the literature, this study shows an adverse effect of TiH 2 on powder densification in NiTi

  17. Powder neutron diffraction study on Pb2Sr2YCu3O8+δ(δ = 0.0 and 1.67)

    International Nuclear Information System (INIS)

    Fujishita, Hideshi; Sato, Masatoshi; Morii, Yukio; Funahashi, Satoru.

    1993-01-01

    Powder neutron diffraction patterns of Pb 2 Sr 2 YCu 3 O 8+δ (δ = 0.0 and 1.67) were analyzed by Rietveld method. For δ = 0, it had been indicated, by powder X-ray diffraction, that the structure was a monoclinic one. The R factors of the present analysis for the monoclinic structure were about 3/4 of those for the previous orthorhombic ones. The structure was almost the same as the previous X-ray result except z (02). For the annealed phase, the tetragonal and the orthorhombic structures had been presented by X-ray diffraction and by neutron diffraction, respectively. The R factors of the present analysis for the orthorhombic structure were about 5/6 of those for the tetragonal structure. The distance between the Pb plane and the oxygen deficient Cu plane was found to become larger in proportion to δ, though there occurs a phase separation in low δ region. (author)

  18. Validation of molecular crystal structures from powder diffraction data with dispersion-corrected density functional theory (DFT-D)

    International Nuclear Information System (INIS)

    Streek, Jacco van de; Neumann, Marcus A.

    2014-01-01

    The accuracy of 215 experimental organic crystal structures from powder diffraction data is validated against a dispersion-corrected density functional theory method. In 2010 we energy-minimized 225 high-quality single-crystal (SX) structures with dispersion-corrected density functional theory (DFT-D) to establish a quantitative benchmark. For the current paper, 215 organic crystal structures determined from X-ray powder diffraction (XRPD) data and published in an IUCr journal were energy-minimized with DFT-D and compared to the SX benchmark. The on average slightly less accurate atomic coordinates of XRPD structures do lead to systematically higher root mean square Cartesian displacement (RMSCD) values upon energy minimization than for SX structures, but the RMSCD value is still a good indicator for the detection of structures that deserve a closer look. The upper RMSCD limit for a correct structure must be increased from 0.25 Å for SX structures to 0.35 Å for XRPD structures; the grey area must be extended from 0.30 to 0.40 Å. Based on the energy minimizations, three structures are re-refined to give more precise atomic coordinates. For six structures our calculations provide the missing positions for the H atoms, for five structures they provide corrected positions for some H atoms. Seven crystal structures showed a minor error for a non-H atom. For five structures the energy minimizations suggest a higher space-group symmetry. For the 225 SX structures, the only deviations observed upon energy minimization were three minor H-atom related issues. Preferred orientation is the most important cause of problems. A preferred-orientation correction is the only correction where the experimental data are modified to fit the model. We conclude that molecular crystal structures determined from powder diffraction data that are published in IUCr journals are of high quality, with less than 4% containing an error in a non-H atom

  19. Reflection-mode x-ray powder diffraction cell for in situ studies of electrochemical reactions

    International Nuclear Information System (INIS)

    Roberts, G.A.; Stewart, K.D.

    2004-01-01

    The design and operation of an electrochemical cell for reflection-mode powder x-ray diffraction experiments are discussed. The cell is designed for the study of electrodes that are used in rechargeable lithium batteries. It is designed for assembly in a glove box so that air-sensitive materials, such as lithium foil electrodes and carbonate-based electrolytes with lithium salts, can be used. The cell uses a beryllium window for x-ray transmission and electrical contact. A simple mechanism for compressing the electrodes is included in the design. Sample results for the cell are shown with a Cu Kα source and a position-sensitive detector

  20. Parallel beam powder diffraction study on the A1C60 system (A=K, Rb)

    International Nuclear Information System (INIS)

    Faigel, G.; Tegze, M.; Bortel, G.; Forro, L.; Oszlanyi, G.; Stephens, P.W.

    1994-01-01

    We report x-ray powder diffraction studies on Rb x C 60 and K x C 60 . It is shown that at room temperature there exist stoichiometric compounds in the Rb x C 60 and K x C 60 systems at the x = 1 composition. Their equilibrium structures are pseudo body centered orthorhombic. The C 60 -C 60 intermolecular separation (9.1 A) is the shortest among the known alkali-fullerides. A first order phase transition is observed at about 380 K from the high temperature fcc phase to the room temperature orthorhombic phase. (orig.)

  1. Determination of Ni(II) crystal structure by powder x-ray diffraction ...

    African Journals Online (AJOL)

    X-ray powder diffraction pattern was used to determine the length of the unit cell, “a”, the lattice structure type, and the number of atoms per unit cell of Ni(II) crystal. The “a” value was determined to be 23.66 ± 0.005 Å, particle size of 34.87 nm, volume 13.24 Å and Strain value ε = 9.8 x 10-3. The cell search on PXRD patterns ...

  2. The Crystal Structure of the Malaria Pigment Hemozoin as Elucidated by X-ray Powder Diffraction

    DEFF Research Database (Denmark)

    Straasø, Tine

    survival. Successful inhibition of hemozoin crystallization will lead to parasitic death and thus break the cycle. The aim of this thesis is to elucidate the structure of hemozoin by means of X-ray diffraction techniques. Knowledge of the structure will help facilitate intelligent drug design in the future....... As part of the project an all-in-vacuum powder diffractometer was developed, which provides data with a minimum background level and an improved signal-to-noise ratio. Moreover, the diffractometer is designed with the particular purpose of decreasing the number of parameters to be fitted. Installation...

  3. A new energy-dispersive powder diffraction facility at the SRS

    International Nuclear Information System (INIS)

    Clark, S.M.

    1996-01-01

    A new energy-dispersive powder diffraction facility has been constructed on the 6 T wiggler beam line of the Daresbury Laboratory Synchrotron Radiation Source. This paper describes the facility, in particular the beam definition apparatus (front end), the detector positioning system (back end), a 10 000 kN loading frame and high pressure cell and the counting and control electronics. Some recent results are presented including a study of the compressibility of talc and the phase I→II transition of ammonium chloride. (orig.)

  4. The X-ray powder diffraction pattern and lattice parameters of perovskite

    International Nuclear Information System (INIS)

    Ball, C.J.; Napier, J.G.

    1988-02-01

    The interplanar spacings and intensities of all lines appearing in the X-ray powder diffraction pattern of perovskite have been calculated. Many of the lines occur in groups with a large amount of overlap. As an aid to identifying the lines which are observed, the intensity profiles of the major groups have been plotted. Those lines which are relatively free of overlap and can be identified unambiguously have been used to calculate the lattice parameters, with the results a=5.4424 ± 0.0001 A, b=7.6417 ± 0.0002 A, c=5.3807 ± 0.0001 A

  5. Location of adsorbed species in NO-reduction catalysts by high resolution neutron powder diffraction

    International Nuclear Information System (INIS)

    Fowkes, A.J.; Rosseinsky, M.J.

    1999-01-01

    Complete text of publication follows. Catalysts containing copper ion exchanged into zeolites are attracting considerable attention due to their efficiency for both NO decomposition and the selective catalytic reduction of NO x in so-called lean-burn conditions in automotive exhausts. This presentation will describe the application of in-situ high resolution neutron powder diffraction to study active sites in a Cu-zeolite Y catalyst active for NO decomposition. The study under NO pressure reveals the location of two distinct copper sites for sorption. The influence of copper oxidation state on the structure of both the pristine and NO-loaded zeolites will be discussed. (author)

  6. Neutron powder diffraction and theory-aided structure refinement of rubidium and cesium ureate

    Energy Technology Data Exchange (ETDEWEB)

    Sterri, Kjersti B.; Deringer, Volker L.; Houben, Andreas; Jacobs, Philipp [RWTH Aachen Univ. (Germany). Inst. of Inorganic Chemistry; Kumar, Chogondahalli M.N. [Forschungszentrum Juelich GmbH, Juelich Centre for Neutron Science (JCNS), Outstation at SNS, Oak Ridge National Laboratory, Oak Ridge, TN (United States); Oak Ridge National Laboratory, TN (United States). Chemical and Engineering Materials Div.; Dronskowski, Richard [RWTH Aachen Univ. (Germany). Inst. of Inorganic Chemistry; RWTH Aachen Univ. (Germany). Juelich-Aachen Research Alliance (JARA-HPC)

    2016-08-01

    Urea (CN{sub 2}H{sub 4}O) is a fundamental biomolecule whose derivatives are abundant throughout chemistry. Among the latter, rubidium ureate (RbCN{sub 2}H{sub 3}O) and its cesium analog (CsCN{sub 2}H{sub 3}O) have been described only very recently and form the first structurally characterized salts of deprotonated urea. Here, we report on a neutron diffraction study on the aforementioned alkaline-metal ureates, which affords the positions for all hydrogen atoms (including full anisotropic displacement tensors) and thus allows us to gain fundamental insights into the hydrogen-bonding networks in the title compounds. The structure refinements of the experimental neutron data proceeded successfully using starting parameters from ab initio simulations of atomic positions and anisotropic displacement parameters. Such joint experimental-theoretical refinement procedures promise significant practical potential in cases where complex solids (organic, organometallic, framework materials) are studied by powder diffraction.

  7. Characterisation of microfocused beam for synchrotron powder diffraction using a new X-ray camera

    International Nuclear Information System (INIS)

    Thomas, C; Potter, J; Tang, C C; Lennie, A R

    2012-01-01

    The powder diffraction beamline I11, Diamond Light Source, is being continually upgraded as requirements of the user community evolve. Intensities of X-rays from the I11 in-vacuum electron undulator in the 3 GeV synchrotron fall off at higher energies. By focusing higher energy X-rays, we can overcome flux limitations, and open up new diffraction experiments. Here, we describe characterisation of microfocusing using compound refractive lenses (CRL). For a relatively modest outlay, we have developed an experimental setup and a novel X-ray camera with good sensitivity and a resolution specification suitable for characterising these focusing optics. We show that vertical oscillations in the focused beam compromise resolution of the source imaged by the CRL. Nevertheless, we have measured CRL focusing properties, and demonstrate the use of energy scanning to determine lens alignment. Real benefits of the intensity gain are illustrated.

  8. Characterization of monoclinic crystals in tablets by pattern-fitting procedure using X-ray powder diffraction data.

    Science.gov (United States)

    Yamamura, Shigeo; Momose, Yasunori

    2003-06-18

    The purpose of this study is to characterize the monoclinic crystals in tablets by using X-ray powder diffraction data and to evaluate the deformation feature of crystals during compression. The monoclinic crystals of acetaminophen and benzoic acid were used as the samples. The observed X-ray diffraction intensities were fitted to the analytic expression, and the fitting parameters, such as the lattice parameters, the peak-width parameters, the preferred orientation parameter and peak asymmetric parameter were optimized by a non-linear least-squares procedure. The Gauss and March distribution functions were used to correct the preferred orientation of crystallites in the tablet. The March function performed better in correcting the modification of diffraction intensity by preferred orientation of crystallites, suggesting that the crystallites in the tablets had fiber texture with axial orientation. Although a broadening of diffraction peaks was observed in acetaminophen tablets with an increase of compression pressure, little broadening was observed in the benzoic tablets. These results suggest that "acetaminophen is a material consolidating by fragmentation of crystalline particles and benzoic acid is a material consolidating by plastic deformation then occurred rearrangement of molecules during compression". A pattern-fitting procedure is the superior method for characterizing the crystalline drugs of monoclinic crystals in the tablets, as well as orthorhombic isoniazid and mannitol crystals reported in the previous paper.

  9. Methods for production of aluminium powders and their application fields

    Energy Technology Data Exchange (ETDEWEB)

    Gopienko, V.G.; Kiselev, V.P.; Zobnina, N.S. (Vsesoyuznyj Nauchno-Issledovatel' skij i Proektnyj Inst. Alyuminievoj, magnievoj i ehlektrodnoj promyshlennosti (USSR))

    1984-12-01

    Different types of powder products made of alluminium and its alloys (powder, fine powders, granules and pastes) as well as their basic physicochemical properties are briefly characterized. The principle methods for alluminium powder production are outlined: physicochemical methods, the melt spraying by compressed gas being the mostly developed among them, and physico-mechanical ones. Main application spheres for powder productions of aluminium and its alloys are reported in short.

  10. Methods for production of aluminium powders and their application fields

    International Nuclear Information System (INIS)

    Gopienko, V.G.; Kiselev, V.P.; Zobnina, N.S.

    1984-01-01

    Different types of powder products made of alluminium and its alloys (powder, fine powders, granules and pastes) as well as their basic physicochemical properties are briefly characterized. The principle methods for alluminium powder production are outlined: physicochemical methods, the melt spraying by compressed gas being the mostly developed among them, and physico-mechanical ones. Main application spheres for powder productions of aluminium and its alloys are reported in short

  11. Identification of phases in zinc alloy powders using electron backscatter diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Perez, Martin G. [Graduate Center for Materials Research, University of Missouri-Rolla, Rolla, MO 65409 (United States); Kenik, Edward A. [Oak Ridge National Laboratory, 100 Bethel Valley Rd., Bldg. 4515, MS-6064, P.O. Box 2008, Oak Ridge, TN 37831 (United States); O' Keefe, Matthew J. [Graduate Center for Materials Research, University of Missouri-Rolla, Rolla, MO 65409 (United States)]. E-mail: mjokeefe@umr.edu; Miller, F. Scott [Graduate Center for Materials Research, University of Missouri-Rolla, Rolla, MO 65409 (United States); Johnson, Benedict [Graduate Center for Materials Research, University of Missouri-Rolla, Rolla, MO 65409 (United States)

    2006-05-25

    Scanning electron microscopy and electron backscatter diffraction (EBSD) were used for the structural characterization of phases in Zn alloy powders. Commercial Zn alloy powders contained additions of <1000 ppm of Bi, In, Al or Mg. Bismuth and In have extremely low solubility in Zn and form intermetallic Bi-In compounds which segregate to the Zn grain boundaries. The Bi-In phases were <0.3 {mu}m in size, had low melting points, and were not abundant enough for EBSD analysis. Increasing the alloying additions 20-40-fold resulted in Bi-In phases >1 {mu}m that could be used for EBSD analysis for phase characterization. Deformation-free microstructures were obtained by mechanical polishing and ion milling. The Zn matrix was characterized as Zn via EBSD. A BiIn{sub 2} phase was identified in the powder microstructures via EBSD. An In phase with 8-9 wt.% Bi was identified using low voltage energy dispersive spectroscopy and closely matched the composition predicted by the Bi-In phase diagram.

  12. Crystal structure solution of hydrides containing natEu from neutron powder diffraction data

    International Nuclear Information System (INIS)

    Kohlmann, H.

    1999-01-01

    Complete text of publication follows. The location of hydrogen in crystal structures of metal hydrides usually requires neutron diffraction data. Some elements, however, show excessively high absorption cross sections, σ a , for neutrons, thus making this technique seemingly impractical. Therefore no complete, refined crystal structure data of europium hydrides (σ a ( nat Eu) = .4530 barns at λ = 179.8 pm [1]) have been reported so far. It is shown that the absorption can be reduced to a value reasonable for neutron diffraction experiments by taking advantage of the wavelength dependence of σ a combined with the use of annular samples at advanced diffractometers. Neutron powder diffraction data on several nat Eu containing deuterides suitable for the ab initio crystal structure solution and refinement have been taken at D20 and D4 (ILL, Grenoble). The crystal chemistry of these europium hydrides, among them the two new compounds EuMg 2 H 6 and EuMgH 4 [2], is discussed. (author) [1] V.F. Sears, Neutron News 1992, 3, 26-37.; [2] H. Kohlmann, F. Gingl, T. Hansen, K. Yvon, Angew. Chem. Int. Ed. Eng. 1999, 38, accepted

  13. Capillary based Li-air batteries for in situ synchrotron X-ray powder diffraction studies

    DEFF Research Database (Denmark)

    Storm, Mie Møller; Johnsen, Rune E.; Younesi, Reza

    2015-01-01

    For Li-air batteries to reach their full potential as energy storage system, a complete understanding of the conditions and reactions in the battery during operation is needed. To follow the reactions in situ a capillary-based Li-O2 battery has been developed for synchrotron-based in situ X......-ray powder diffraction (XRPD). In this article, we present the results for the analysis of 1st and 2nd deep discharge and charge for a cathode being cycled between 2 and 4.6 V. The crystalline precipitation of Li2O2 only is observed in the capillary battery. However, there are indications of side reactions...... of constant exposure of X-ray radiation to the electrolyte and cathode during charge of the battery was also investigated. X-ray exposure during charge leads to changes in the development of the intensity and the FWHM of the Li2O2 diffraction peaks. The X-ray diffraction results are supported by ex situ X...

  14. Syntheses and crystal structure determination by X-ray powder diffraction of new compounds of Benzovesamicol

    International Nuclear Information System (INIS)

    Rukiah, M.; Assaad, Th.

    2012-06-01

    The compound 2,2,2-Trifluoro-N-(1a,2,7,7 a-tetra-hydronaphtho[2,3-b]oxiren-3-yl)- acetamide, C 1 2H 1 0F 3 NO 2 , an important precursor in the preparation of benzovesamicol analogues for the diagnosis of Alzheimers disease, was prepared by the epoxidation of 5,8-dihydronaphthalene-1-amine using 3-chloroperoxybenzoic acid. The structure was determined by X-ray powder diffraction, multinuclear NMR spectroscopy and FT-IR spectroscopy. A pair of molecules form intermolecular N- H...O hydrogen bonds, involving the amino and oxirene groups, to produce a dimer.The two racemic compounds (2RS,3RS)-5-amino-3-(4-phenylpiperazin-1-yl)-1,2,3,4 tetrahydronaphthalene-2-ol, C 2 0H 2 5N 3 O, (I) and (2RS,3RS)-5-amino-3-[4-(3- methoxyphenyl)piperazin-1-yl]-1,2,3,4-tetrahydronaphthalene-2-ol, C 2 1H 2 7N 3 O 2 , (II) important benzovesamicol analogues for the diagnosis of Alzheimer's disease, have been synthesized and characterized by FT-IR, and 1 H and 13 C NMR spectroscopic analyses. The crystal structures were analyses using powder diffraction as no suitable single crystal were obtained. The two compounds are racemic mixtures of enantiomers which crystallize in the monoclinic system in a centrosymmetric space group (P21/c). Crystallography, in particular powder X-ray diffraction, was pivotal in revealing that the enantio-resolution did not succeed. In two compounds, the piperazine ring has a chair conformation, while the cyclohexene ring assumes a half-chair conformation. In (I) the crystal packing is mediated by weak contacts, principally by complementary intermolecular N--H...O hydrogen bonds that connect successive molecules into a chain. Further stabilization is provided by weak C--H...N contacts and by a weak intermolecular C--H...π interaction. While in (II), the crystal packing is dominated by intermolecular O--H...N hydrogen bonding which links molecules along the c direction. (authors)

  15. Coherent diffractive imaging methods for semiconductor manufacturing

    Science.gov (United States)

    Helfenstein, Patrick; Mochi, Iacopo; Rajeev, Rajendran; Fernandez, Sara; Ekinci, Yasin

    2017-12-01

    The paradigm shift of the semiconductor industry moving from deep ultraviolet to extreme ultraviolet lithography (EUVL) brought about new challenges in the fabrication of illumination and projection optics, which constitute one of the core sources of cost of ownership for many of the metrology tools needed in the lithography process. For this reason, lensless imaging techniques based on coherent diffractive imaging started to raise interest in the EUVL community. This paper presents an overview of currently on-going research endeavors that use a number of methods based on lensless imaging with coherent light.

  16. Synthesis of alumina powders by precipitation method and solvothermal treatment

    International Nuclear Information System (INIS)

    Politchuk, J.O.; Lima, N.B.; Lazar, D.R.R.; Ussui, V.; Yoshito, W.K.

    2012-01-01

    The improvement of alumina powders synthesis processes has been focused on the preparation of ceramic powders with well defined crystalline structure and with high specific surface area and nanometric particle size without formation of hard agglomerates. For this purpose the precipitation step should be studied and and also the temperature of alumina crystallization should be reduced. The aim of this study was to obtain alumina powders by hydroxide precipitation with ammonia in the presence of cationic surfactant, followed by solvothermal treatment and calcination. The powders were characterized by TG/DTA, X-ray diffraction, surface area measurements by gas adsorption (BET) and scanning electron microscopy. The results showed that powders produced by solvothermal treatment without surfactant have higher crystallinity. However the presence of CTAB enhances 240% the specific surface area compared with powders produced without this reagent (author)

  17. Combined experimental powder X-ray diffraction and DFT data to obtain the lowest energy molecular conformation of friedelin

    International Nuclear Information System (INIS)

    Oliveira, Djalma Menezes de; Mussel, Wagner da Nova; Duarte, Lucienir Pains; Silva, Gracia Divina de Fatima; Duarte, Helio Anderson; Gomes, Elionai Cassiana de Lima; Guimaraes, Luciana; Vieira Filho, Sidney A.

    2012-01-01

    Friedelin molecular conformers were obtained by Density Functional Theory (DFT) and by ab initio structure determination from powder X-ray diffraction. Their conformers with the five rings in chair-chair-chair-boat-boat, and with all rings in chair, are energy degenerated in gas-phase according to DFT results. The powder diffraction data reveals that rings A, B and C of friedelin are in chair, and rings D and E in boat-boat, conformation. The high correlation values among powder diffraction data, DFT and reported single crystal data indicate that the use of conventional X-ray diffractometer can be applied in routine laboratory analysis in the absence of a single-crystal diffractometer. (author)

  18. Combined experimental powder X-ray diffraction and DFT data to obtain the lowest energy molecular conformation of friedelin

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Djalma Menezes de; Mussel, Wagner da Nova; Duarte, Lucienir Pains; Silva, Gracia Divina de Fatima; Duarte, Helio Anderson; Gomes, Elionai Cassiana de Lima [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Quimica; Guimaraes, Luciana [Universidade Federal de Sao Joao Del-Rei (UFSJ), MG (Brazil). Dept. de Ciencias Naturais; Vieira Filho, Sidney A., E-mail: bibo@ef.ufop.br [Universidade Federal de Ouro Preto (UFOP), MG (Brazil). Dept. de Farmacia

    2012-07-01

    Friedelin molecular conformers were obtained by Density Functional Theory (DFT) and by ab initio structure determination from powder X-ray diffraction. Their conformers with the five rings in chair-chair-chair-boat-boat, and with all rings in chair, are energy degenerated in gas-phase according to DFT results. The powder diffraction data reveals that rings A, B and C of friedelin are in chair, and rings D and E in boat-boat, conformation. The high correlation values among powder diffraction data, DFT and reported single crystal data indicate that the use of conventional X-ray diffractometer can be applied in routine laboratory analysis in the absence of a single-crystal diffractometer. (author)

  19. Neutron diffraction studies on GdB{sub 6} and TbB{sub 6} powders

    Energy Technology Data Exchange (ETDEWEB)

    Luca, S.E.; Amara, M.; Galera, R.M.; Givord, F.; Granovsky, S.; Isnard, O.; Beneu, B

    2004-07-15

    We report here the first powder neutron diffraction study of GdB{sub 6} and TbB{sub 6}. GdB{sub 6} and TbB{sub 6} order antiferromagnetically at 15 and 21 K, respectively. In both compounds the transition at T{sub N} is of the first order. Moreover GdB{sub 6} presents a second spontaneous magnetic transition at T{sup *}=8 K. The present study shows that, in both compounds, the magnetic propagation vectors belong to the <((1)/(4)) ((1)/(4)) ((1)/(2))> star and that the direction of the magnetic moment is perpendicular to the ((1)/(2)) component of the wave-vector in GdB{sub 6}, while in TbB{sub 6} the moment is parallel to it. The deduced low-temperature values of the magnetic moments agree with those of the respective rare-earth trivalent ions.

  20. Neutron diffraction studies on GdB6 and TbB6 powders

    International Nuclear Information System (INIS)

    Luca, S.E.; Amara, M.; Galera, R.M.; Givord, F.; Granovsky, S.; Isnard, O.; Beneu, B.

    2004-01-01

    We report here the first powder neutron diffraction study of GdB 6 and TbB 6 . GdB 6 and TbB 6 order antiferromagnetically at 15 and 21 K, respectively. In both compounds the transition at T N is of the first order. Moreover GdB 6 presents a second spontaneous magnetic transition at T * =8 K. The present study shows that, in both compounds, the magnetic propagation vectors belong to the star and that the direction of the magnetic moment is perpendicular to the ((1)/(2)) component of the wave-vector in GdB 6 , while in TbB 6 the moment is parallel to it. The deduced low-temperature values of the magnetic moments agree with those of the respective rare-earth trivalent ions

  1. Phase transitions in Rb2UBr6 observed by neutron powder diffraction

    International Nuclear Information System (INIS)

    Maletka, K.; Ressouche, E.; Tellgren, R.; Delaplane, R.; Szczepaniak, W.; Rycerz, L.; Zablocka-Malecka, M.

    1997-01-01

    The behaviour of the Rb 2 UBr 6 ionic conductor is studied as a function of the temperature by neutron powder diffraction. The low- room and high temperature structures have been determined. At low temperature range 4.2-80 K the compound crystallizes in a monoclinic unit cell with P2 1 /c space group. Among 80 and 853 K the compound crystallizes in a tetragonal unit cell with space group P4/mnc. At 300 K the lattice constants are; a = b 7,745(1), c = 11.064(1) A. At the temperature range 853-960 K is observed the trigonal phase with P-3m1 space group. Above the phase transitions occurring at 960 K the compound crystallizes in the cubic unit cell with Fm3m space group. (author)

  2. Characterization of polymorphic solid-state changes using variable temperature X-ray powder diffraction

    DEFF Research Database (Denmark)

    Karjalainen, Milja; Airaksinen, Sari; Rantanen, Jukka

    2005-01-01

    The aim of this study was to use variable temperature X-ray powder diffraction (VT-XRPD) to understand the solid-state changes in the pharmaceutical materials during heating. The model compounds studied were sulfathiazole, theophylline and nitrofurantoin. This study showed that the polymorph form...... of sulfathiazole SUTHAZ01 was very stable and SUTHAZ02 changed as a function of temperature to SUTHAZ01. Theophylline monohydrate changed via its metastable form to its anhydrous form during heating and nitrofurantoin monohydrate changed via amorphous form to its anhydrous form during heating. The crystallinity...... to the anhydrous form. The average crystallite size of sulfathiazole samples varied only a little during heating. The average crystallite size of both theophylline and nitrofurantoin monohydrate decreased during heating. However, the average crystallite size of nitrofurantoin monohydrate returned back to starting...

  3. Structure analysis of K3H(SO4)2 by neutron powder diffraction

    International Nuclear Information System (INIS)

    Murakami, Satoshi; Kuroiwa, Yoshihiro; Noda, Yukio; Nakai, Yusuke; Kamiyama, Takashi; Asano, Hajime.

    1993-01-01

    Neutron powder diffraction experiments of K 3 H(SO 4 ) 2 were carried out at KENS-HRP station in order to obtain the positional parameters of hydrogen nuclei. The data was taken at six different temperatures from room temperature to 20K. Even though K 3 H(SO 4 ) 2 contained a hydrogen atom, the structural analysis was successfully performed by using a program RIETAN. Concerning the hydrogen position, four different models give almost the same R-factor so that the state of the hydrogen nucleus is not uniquely determined. The result based on the assumption that a hydrogen nucleus occupies two sites shows that the distance of split hydrogen nuclei is shorter than the distance of hydrogen electron clouds. This result suggests that a large polarizability exists in a hydrogen atom. (author)

  4. A powder neutron diffraction study of stoichiometric silver beta alumina at 4.2 K

    International Nuclear Information System (INIS)

    Newsam, J.M.; Tofield, B.C.

    1980-10-01

    The low-temperature structure of stoichiometric silver beta alumina, AgAl 11 O 17 , is described for the first time. A powder neutron diffraction study at 4.2 K reveals that there is a single three-fold silver location of unit occupancy in each mirror plane. The silver site lies between the mid-oxygen and Beevers-Ross positions where the Ag-O contact distances can be minimised. The Ag-O interactions, in particular the cooperative movement of the spacer oxygens, are responsible for the superlattice which has been described previously. The Beevers-Ross, anti-Beevers-Ross and interstitial aluminium sites are vacant and the c-axis constant is expanded relative to the non-stoichiometric parent. (author)

  5. 2010 Diffraction Methods in Structural Biology

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Ana Gonzalez

    2011-03-10

    Advances in basic methodologies have played a major role in the dramatic progress in macromolecular crystallography over the past decade, both in terms of overall productivity and in the increasing complexity of the systems being successfully tackled. The 2010 Gordon Research Conference on Diffraction Methods in Structural Biology will, as in the past, focus on the most recent developments in methodology, covering all aspects of the process from crystallization to model building and refinement, complemented by examples of structural highlights and complementary methods. Extensive discussion will be encouraged and it is hoped that all attendees will participate by giving oral or poster presentations, the latter using the excellent poster display area available at Bates College. The relatively small size and informal atmosphere of the meeting provides an excellent opportunity for all participants, especially younger scientists, to meet and exchange ideas with leading methods developers.

  6. Structure of La2Cu2O5 by high-resolution synchrotron X-ray powder diffraction

    International Nuclear Information System (INIS)

    La Placa, S.J.; Bringley, J.F.; Scott, B.A.; Cox, D.E.

    1993-01-01

    Dicopper(II) dilanthanum pentaoxide, La 2 Cu 2 O 5 , M r =484.90, orthorhombic, Pbam. At T=300 K: a=5.5490(1), b=10.4774(2), c=3.8796(1) A, V=225.557(8) A 3 , Z=2, D x =7.139 g cm -3 , λ=1.2000 A. Final R I =6.20, R p =14.6 and R wp =20.61%, 124 independent reflections observed. The structure has been refined from high-resolution synchrotron X-ray powder diffraction data using the Rietveld method. It is of the oxygen-defect perovskite type and is composed entirely of corner-shared CuO 5 square pyramids, which share oxygen vacancies forming vacancy tunnels along the c axis. The La atoms reside at a perovskite-like A-site and are tenfold coordinated by oxygen. (orig.)

  7. A comparative study of the use of powder X-ray diffraction, Raman and near infrared spectroscopy for quantification of binary polymorphic mixtures of piracetam.

    Science.gov (United States)

    Croker, Denise M; Hennigan, Michelle C; Maher, Anthony; Hu, Yun; Ryder, Alan G; Hodnett, Benjamin K

    2012-04-07

    Diffraction and spectroscopic methods were evaluated for quantitative analysis of binary powder mixtures of FII(6.403) and FIII(6.525) piracetam. The two polymorphs of piracetam could be distinguished using powder X-ray diffraction (PXRD), Raman and near-infrared (NIR) spectroscopy. The results demonstrated that Raman and NIR spectroscopy are most suitable for quantitative analysis of this polymorphic mixture. When the spectra are treated with the combination of multiplicative scatter correction (MSC) and second derivative data pretreatments, the partial least squared (PLS) regression model gave a root mean square error of calibration (RMSEC) of 0.94 and 0.99%, respectively. FIII(6.525) demonstrated some preferred orientation in PXRD analysis, making PXRD the least preferred method of quantification. Copyright © 2012 Elsevier B.V. All rights reserved.

  8. Quantitative determination of amorphous content in ceramic materials using x-ray powder diffraction

    International Nuclear Information System (INIS)

    Kuchinski, M.A.; Hubbard, C.R.

    1988-01-01

    A quantitative technique which employs a modified method of additions approach to analyze for low amorphous content in crystalline matrices was developed and tested. Known amounts of amorphous material are added to the starting powder. The method uses the ratio of a measure of the intensity of the amorphous phase corrected for background to the background corrected intensity of a reference line from a crystalline phase. The amorphous spiking phase must be close in composition to the amorphous phase existing in the analyte. A critical step of the method is to correctly establish the background intensity. A completely crystalline material of similar scattering power was used to establish background intensity

  9. Method of producing radioactive carbon powder

    International Nuclear Information System (INIS)

    Imamura, Y.

    1980-01-01

    Carbon powder, placed in a hermetically closed apparatus under vacuum together with radium ore, adsorbs radon gas emanating from the radium ore thus producing a radioactive carbonaceous material, the radioactivity of which is due to the presence of adsorbed radon. The radioactive carbon powder thus obtained has excellent therapeutical efficacy and is suitable for a variety of applications because of the mild radioactivity of radon. Radium ore permits substantially limitlessly repeated production of the radioactive carbon powder

  10. An Inquiry-Based Project Focused on the X-Ray Powder Diffraction Analysis of Common Household Solids

    Science.gov (United States)

    Hulien, Molly L.; Lekse, Jonathan W.; Rosmus, Kimberly A.; Devlin, Kasey P.; Glenn, Jennifer R.; Wisneski, Stephen D.; Wildfong, Peter; Lake, Charles H.; MacNeil, Joseph H.; Aitken, Jennifer A.

    2015-01-01

    While X-ray powder diffraction (XRPD) is a fundamental analytical technique used by solid-state laboratories across a breadth of disciplines, it is still underrepresented in most undergraduate curricula. In this work, we incorporate XRPD analysis into an inquiry-based project that requires students to identify the crystalline component(s) of…

  11. Simvastatin: structure solution of two new low-temperature phases from synchrotron powder diffraction and ss-NMR

    Czech Academy of Sciences Publication Activity Database

    Hušák, M.; Kratochvíl, B.; Jegorov, A.; Brus, Jiří; Maixner, J.; Rohlíček, J.

    2010-01-01

    Roč. 21, č. 3 (2010), s. 511-518 ISSN 1040-0400 R&D Projects: GA AV ČR IAA400500602; GA MŠk 2B08021 Institutional research plan: CEZ:AV0Z40500505 Keywords : crystal structure * simvastatin * powder diffraction Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.727, year: 2010

  12. Validation of molecular crystal structures from powder diffraction data with dispersion-corrected density functional theory (DFT-D)

    DEFF Research Database (Denmark)

    van de Streek, Jacco; Neumann, Marcus A

    2014-01-01

    In 2010 we energy-minimized 225 high-quality single-crystal (SX) structures with dispersion-corrected density functional theory (DFT-D) to establish a quantitative benchmark. For the current paper, 215 organic crystal structures determined from X-ray powder diffraction (XRPD) data and published...

  13. An in situ Study of NiTi Powder Sintering Using Neutron Diffraction

    Directory of Open Access Journals (Sweden)

    Gang Chen

    2015-04-01

    Full Text Available This study investigates phase transformation and mechanical properties of porous NiTi alloys using two different powder compacts (i.e., Ni/Ti and Ni/TiH2 by a conventional press-and-sinter means. The compacted powder mixtures were sintered in vacuum at a final temperature of 1373 K. The phase evolution was performed by in situ neutron diffraction upon sintering and cooling. The predominant phase identified in all the produced porous NiTi alloys after being sintered at 1373 K is B2 NiTi phase with the presence of other minor phases. It is found that dehydrogenation of TiH2 significantly affects the sintering behavior and resultant microstructure. In comparison to the Ni/Ti compact, dehydrogenation occurring in the Ni/TiH2 compact leads to less densification, yet higher chemical homogenization, after high temperature sintering but not in the case of low temperature sintering. Moreover, there is a direct evidence of the eutectoid decomposition of NiTi at ca. 847 and 823 K for Ni/Ti and Ni/TiH2, respectively, during furnace cooling. The static and cyclic stress-strain behaviors of the porous NiTi alloys made from the Ni/Ti and Ni/TiH2 compacts were also investigated. As compared with the Ni/Ti sintered samples, the samplessintered from the Ni/TiH2 compact exhibited a much higher porosity, a higher close-to-total porosity, a larger pore size and lower tensile and compressive fracture strength.

  14. Computer x-ray powder diffraction patterns and densities for corundum, aluminium, zirconium, delta-UZr2 and the zirconium hydrides

    International Nuclear Information System (INIS)

    Ferguson, I.F.

    1976-11-01

    The computer-calculated X-ray powder diffraction patterns and theoretical densities of α-Al 2 O 3 ; Al; α-Zr; β-Zr; delta-UZr 2 ; γ, delta - and epsilon-zirconium hydrides are presented. Brief comments are given on some of the published X-ray powder diffraction data on these phases. (author)

  15. The magnetic structure of GdNi2B2C investigated by neutron powder diffraction

    International Nuclear Information System (INIS)

    Barcza, A.; Rotter, M.; Doerr, M.; Beuneu, B.

    2005-01-01

    Full text: The group of ReT 2 B 2 C (Re=rare earth, T=transition metal) shows a very interesting interplay between magnetism and superconductivity due to the rare earth metals. In this work the magnetism of GdNi 2 B 2 C was studied with neutron diffraction. Previous investigations with x-ray diffraction methods have determined the crystal structure as a body centered tetragonal structure (I 4/mmm). Hot neutrons were used for the diffraction experiment, because the absorption cross section of Gd is significantly smaller for short wavelengths. The investigated compound orders magnetically at TN=19.5 K, and so the experiment was carried out at two temperatures, namely 30 K and 2.2 K. The results show a incommensurate spin structure with a propagation vector of (0.55 0 0). To confirm this results additional simulations of the spin structure were done based on the Standard Model of rare earth magnetism. A neutron diffraction pattern was calculated using the McPhase program package and is compared to the experimental data. (author)

  16. Crushing method for nuclear fuel powder

    International Nuclear Information System (INIS)

    Hasegawa, Shin-ichi; Tsuchiya, Haruo.

    1997-01-01

    A crushing medium is contained in mill pots disposed at the circumferential periphery of a main axis. The diameter of each mill pot is determined such that powdery nuclear fuels containing aggregated powders and ground and mixed powders do not reach criticality. A plurality of mill pots are revolved in the direction of the main axis while each pots rotating on its axis. Powdery nuclear fuels containing aggregated powders are conveyed to a supply portion of the moll pot, and an inert gas is supplied to the supply portion. The powdery nuclear fuels are supplied from the supply portion to the inside of the mill pots, and the powdery nuclear fuels containing aggregated powders are crushed by centrifugal force caused by the rotation and the revolving of the mill pots by means of the crushing medium. UO 2 powder in uranium oxide fuels can be crushed continuously. PuO 2 powder and UO 2 powder in MOX fuels can be crushed and mixed continuously. (I.N.)

  17. FTIR spectroscopy and X-ray powder diffraction characterization of microcrystalline cellulose obtained from alfa fibers

    Directory of Open Access Journals (Sweden)

    Trache D.

    2013-07-01

    Full Text Available Many cereal straws have been used as raw materials for the preparation of microcrystalline cellulose (MCC. These raw materials were gradually replaced with wood products; nevertheless about 10% of the world overall pulp production is obtained from non-wood raw material. The main interest in pulp made from straw is that it provides excellent fibres for different industries with special properties, and that it is the major available source of fibrous raw material in some geographical areas. The aim of the present work was to characterize microcrystalline cellulose prepared from alfa fibers using the hydrolysis process. The products obtained are characterized with FTIR spectroscopy and X-ray powder diffraction. As a result, FTIR spectroscopy is an appropriate technique for studying changes occurred by any chemical treatment. The spectrum of alfa grass stems shows the presence of lignin and hemicelluloses. However, the cellulose spectrum indicates that the extraction of lignin and hemicellulose was effective. The X-ray analysis indicates that the microcrystalline cellulose is more crystalline than the source material.

  18. Rietveld refinement of magnetic structures from pulsed-neutron-source powder-diffraction data

    International Nuclear Information System (INIS)

    Robinson, R.A.; Lawson, A.C.; Larson, A.C.; Von Dreele, R.B.; Goldstone, J.A.

    1994-01-01

    The General Structure Analysis System, GSAS, has recently been modified to include magnetic neutron- scattering cross-sections. Low-temperature diffraction data have been taken on the hexagonal noncollinear antiferromagnet UPdSn on both the HIPD and the NPD powder diffractometers ail LANSCE. The low-resolution data reveal that the magnetic structure has orthorhombic symmetry (magnetic space group P c m'c2 1 ) between 25K and 40K, and monoclinic symmetry (magnetic space group PC 1121 ) below 25K. The high-resolution data reveal that there are structural distortions with corresponding symmetry changes in each of these phases, to give chemical space groups Cmc2 1 and P2 1 , respectively, while the paramagnetic phase above 40K has space group P6 3 mc. Using GSAS, we have refined data sets from both diffractometers simultaneously, including both magnetic and structural cross-sections. Magnetoelastic coefficients for the distortions have been extracted and we have determined the sign of the coupling between the structural monoclinicity and the magnetic monoclinicity. The magnetic results from Rietveld refinement are in good agreement with model fitting to the integrated intensities of seven independent magnetic reflections and these, in turn, agree with measurements made on the same sample using the constant-wavelength reactor technique. Our results therefore validate, to some level, both the technique of using spallation sources for complicated magnetic structures and the specifics of the GSAS Rietveld code

  19. Neutron Powder Diffraction Studies of Ca2-xSrxCoWO6 Double Perovskites

    International Nuclear Information System (INIS)

    Zhou, Qingdi; Kennedy, Brendan; Elcombe, Margaret

    2005-01-01

    Full text: A series of double perovskite compounds of A 2-x Sr x CoWO 6 (A = Ca, Ba) were synthesized and the room- and variable-temperature structural phase transitions have been studied by synchrotron and neutron powder diffraction techniques. These studies demonstrated that the symmetry increases as the average size of the A-site cation increases. These transitions are associated with the gradual reduction and ultimately removal of the octahedral tiles of the BO 6 octahedra. Temperature dependent structural studies have been undertaken for selected samples. The transition to cubic is continuous in the three Ca doped samples studied as a function of temperature, Ca 2-x Sr x CoWO 6 x = 1.8, 1.7, 1.6, however in each case analysis of the spontaneous strain shows the transition to be tricritical rather than second order in nature. Where observed the temperature induced P2 1 /n to I4/m transition is first order as required by symmetry. (authors)>>>>

  20. X-ray Powder Diffraction for Characterization of Raw Materials in Banknotes.

    Science.gov (United States)

    Marabello, Domenica; Benzi, Paola; Lombardozzi, Antonietta; Strano, Morela

    2017-07-01

    We report about the X-ray powder diffraction characterization of crystalline materials used to produce genuine and counterfeit banknotes, performed with a single-crystal diffractometer that permits fast and nondestructive measurements in different 0.5-mm sized areas; 20-euro denomination genuine banknotes were analyzed, and results were compared with counterfeit banknotes. The analysis shows that the papers used to print real banknotes are composed, as expected, of cotton-based cellulose and titanium dioxide as crystalline additive, but different polymorphs of TiO 2 for different emission countries are evidenced. The counterfeit banknotes are composed of cellulose based on wood pulp; moreover, an unexpected significant quantity of TiO 2 was found to be mixed with calcite, indicating that the paper employed by forgers is not simply a common low-cost type. The crystalline index and intensity ratios between the peaks attributable to cellulose and fillers can provide additional information to trace back paper suppliers for forensic purposes. © 2017 American Academy of Forensic Sciences.

  1. Neutron powder diffraction at a pulsed neutron source: a study of resolution effects

    International Nuclear Information System (INIS)

    Faber, J. Jr.; Hitterman, R.L.

    1985-11-01

    The General Purpose Powder Diffractometer (GPPD), a high resolution (Δd/d = 0.002) time-of-flight instrument, exhibits a resolution function that is almost independent of d-spacing. Some of the special properties of time-of-flight scattering data obtained at a pulsed neutron source will be discussed. A method is described that transforms wavelength dependent data, obtained at a pulsed neutron source, so that standard structural least-squares analyses can be applied. Several criteria are given to show when these techniques are useful in time-of-flight data analysis. 14 refs., 6 figs., 1 tab

  2. Quantitative determination of mineral composition by powder X-ray diffraction

    International Nuclear Information System (INIS)

    Pawloski, G.A.

    1986-01-01

    A method is described of quantitatively determining the mineral composition in a test sample containing a number (m) of minerals from a group (n) of known minerals, wherein n=13, where mless than or equal ton, by x-ray diffraction, comprising: determining from standard samples of the known minerals a set of (n) standard coefficients K/sub j/=(X/sub j//X/sub l/)(I/sub l//I/sub j/) for each mineral (j=2...n) in the group of known minerals (j=2...n) relative to one mineral (l) in the group selected as a reference mineral, where X is the weight fraction of the mineral in a standard sample, and I is the x-ray integrated intensity peak of each mineral obtained from the standard sample; obtaining an x-ray diffraction pattern of the test sample; identifying each of the (m) minerals in the test sample for the x-ray diffraction pattern; calculating the relative weight fractions X/sub j//X/sub l/ for each mineral (j=2...m) compared to the reference mineral (l) from the ratio of the measured highest integrated intensity peak I/sub j/ of each mineral in the test sample to the measured highest integrated intensity peak I/sub l/ of the reference mineral in the test sample, and from the previously determined standard coefficients, X/sub j//X/sub l/=K/sub j/(I/sub j//I/sub l/

  3. Food powders flowability characterization: theory, methods, and applications.

    Science.gov (United States)

    Juliano, Pablo; Barbosa-Cánovas, Gustavo V

    2010-01-01

    Characterization of food powders flowability is required for predicting powder flow from hoppers in small-scale systems such as vending machines or at the industrial scale from storage silos or bins dispensing into powder mixing systems or packaging machines. This review covers conventional and new methods used to measure flowability in food powders. The method developed by Jenike (1964) for determining hopper outlet diameter and hopper angle has become a standard for the design of bins and is regarded as a standard method to characterize flowability. Moreover, there are a number of shear cells that can be used to determine failure properties defined by Jenike's theory. Other classic methods (compression, angle of repose) and nonconventional methods (Hall flowmeter, Johanson Indicizer, Hosokawa powder tester, tensile strength tester, powder rheometer), used mainly for the characterization of food powder cohesiveness, are described. The effect of some factors preventing flow, such as water content, temperature, time consolidation, particle composition and size distribution, is summarized for the characterization of specific food powders with conventional and other methods. Whereas time-consuming standard methods established for hopper design provide flow properties, there is yet little comparative evidence demonstrating that other rapid methods may provide similar flow prediction.

  4. The crystal structures and powder diffraction patterns of the uranium tellurides

    Energy Technology Data Exchange (ETDEWEB)

    Snyder, R.L. (State Univ. of New York, Alfred, NY (USA). Inst. of Ceramic Superconductivity); Nichols, M.C.; Boehme, D.R. (Sandia National Labs., Livermore, CA (USA))

    1990-10-03

    A critical review of all of the reported structures and powder diffraction patterns in the uranium telluride system has been undertaken. Structures that are correct: Cubic -- UTe: no experimental pattern exists. Retain calculated 15--865. Cubic --U{sub 3}Te{sub 4}: retain the poor quality 12--610 but adopt the pattern calculated here. Cubic U{sub 2}Te{sub 3}: no experimental pattern exists. Adopt pattern calculated here. Orthorhombic UTe{sub 2}: Adopt the new pattern of Boehme et al. Monoclinic {alpha}UTe{sub 3} Adopt the new pattern of Boehme et al. Monoclinic {alpha}UTe{sub 3} Adopt the new pattern of Boehme et al. Orthorhombic {beta}UTe{sub 3}: Adopt pattern calculated here. Orthorhombic UTe{sub 5}: Adopt the new pattern of Boehme et al. Structures in need of refinement: Orthorhombic U{sub 2}Te{sub 3}:Adopt pattern calculated here over 34--807. Hexagonal U{sub 7}Te{sub 12}: Adopt pattern calculated here but retain 24--1368. Orthorhombic UTe{sub 1.78}: Adopt pattern calculated here and retain our modified 21--1404 reported for U{sub 4}Te{sub 7}. Orthorhombic UTe{sub 2.5}: Adopt pattern calculated here. Orthorhombic UTe{sub 3.4}: Accept recent pattern of Boehme et al. Phases for which no structures or reliable patterns exist: Orthorhombic U{sub 3}Te{sub 4}: no published pattern. Tetragonal U{sub 3}Te{sub 5}: three patterns 21--1407, 34--766 and 34--896 exit but all are of very poor quality. Phases which probably do not exist: Tetragonal UTe{sub 1.78}, Tetragonal UTe{sub 2}, Cubic UTe{sub 2} U{sub 3}Te{sub 7}(21--1402), U{sub 3}Te{sub 8}(21--1406).

  5. The role of iron in tetrahedrite and tennantite determined by Rietveld refinement of neutron powder diffraction data

    DEFF Research Database (Denmark)

    Andreasen, Jens Wenzel; Makovicky, Emil; Lebech, Bente

    2008-01-01

    Rietveld refinement of neutron powder diffraction data on four samples of synthetic, iron-bearing tetrahedrite (Cu12-xFexSb4S13) with x = 0.28, 0.69, 0.91, 2.19 and four samples of synthetic tennantite (Cu12-xFexAs4S13) with x = 0.33, 0.38, 0.86, 1.5 indicate unambiguously that iron is incorporated...

  6. Application of combined multivariate techniques for the description of time-resolved powder X-ray diffraction data

    Czech Academy of Sciences Publication Activity Database

    Taris, A.; Grosso, M.; Brundu, M.; Guida, V.; Viani, Alberto

    2017-01-01

    Roč. 50, č. 2 (2017), s. 451-461 ISSN 1600-5767 R&D Projects: GA MŠk(CZ) LO1219 Keywords : in situ X-ray powder diffraction * amorphous content * chemically bonded ceramic s * statistical total correlation spectroscopy * multivariate curve resolution Subject RIV: JJ - Other Materials OBOR OECD: Materials engineering Impact factor: 2.495, year: 2016 http://journals.iucr.org/j/issues/2017/02/00/ap5006/index.html

  7. New analytical method for asbestos determination in Syrian soils using X-ray diffraction

    International Nuclear Information System (INIS)

    Kassem, M.

    2009-07-01

    In this work, a standard samples have been prepared by mixing a definite quantity of soil with calculated concentration of asbestos; 1, 2, 4, 8, 10, 20, 40, 60, 80, 100% wt . The samples have been analyzed by x-ray powder diffraction using the same parameters ; 2θ between 5-90, detector step= 0.5 /30 sec. The diffraction peaks intensities have been chosen such a manner than no superposition with those of the soil. confidence levels has been used as accuracy method for error calculation of the peaks positions. (author)

  8. Ti3SiC2 Synthesis by Powder Metallurgical Methods

    OpenAIRE

    Kero, Ida; Antti, Marta-Lena; Odén, Magnus

    2007-01-01

    Titanium silicon carbide MAX phase was synthesised by a powder metallurgical method from ball milled TiC/Si powders of two different compositions, with TiC/Si ratios of 3:2 and 3:2.2 respectively. The cold pressed samples were analysed by dilatometry under flowing argon or sintered under vacuum for different times. The sintered samples were evaluated using x-ray diffraction (XRD). This study showed that titanium carbide was always present as a secondary phase and silicon carbide accompanied t...

  9. Fabrication of Ti-Ni-Cu shape memory alloy powders by ball milling method

    International Nuclear Information System (INIS)

    Kang, S.; Nam, T.

    2001-01-01

    Ti-Ni and Ti-Ni-Cu shape memory alloy powders have been fabricated by ball milling method, and then alloying behavior and transformation behavior were investigated by means of optical microscopy, electron microscopy, X-ray diffraction and differential scanning calorimetry. As milled Ti-Ni powders fabricated with milling time less than 20 hrs was a mixture of pure elemental Ti and Ni, and therefore it was unable to obtain alloy powders because the combustion reaction between Ti and Ni occurred during heat treatment. Since those fabricated with milling time more than 20 hrs was a mixture of Ti-rich and Ni-rich Ti-Ni solid solution, however, it was possible to obtain alloy powders without the combustion reaction during heat treatment. Clear exothermic and endothermic peaks appeared in the cooling and heating curves, respectively in DSC curves of 20 hrs and 30 hrs milled Ti-Ni powders. On the other hand, in DSC curves of 1 hr, 10 hrs, 50 hrs and 100 hrs, the thermal peaks were almost discernible. The most optimum ball milling time for fabricating Ti-Ni alloy powders was 30 hrs. Ti-40Ni-10Cu(at%) alloy powders were fabricated successfully by ball milling conditions with rotating speed of 100 rpm and milling time of 30 hrs. (author)

  10. Operation manual for EDXRDDA - a software package for Bragg peak analysis of energy dispersive powder X-ray diffraction data

    International Nuclear Information System (INIS)

    Jayaswal, Balhans; Vijaykumar, V.; Momin, S.N.; Sikka, S.K.

    1992-01-01

    EDXRDDA is a software package for analysis of raw data for energy dispersive x-ray diffraction from powder samples. It resolves the spectra into individual peaks by a constrained non-linear least squares method (Hughes and Sexton, 1988). The profile function adopted is the Gaussian/Lorentzian product with the mixing ratio refinable in the program. The program is implemented on an IBM PC and is highly interactive with extensive plotting facilities. This report is a user's guide for running the program. In the first step after inputting the spectra, the full spectra is plotted on the screen. The user then chooses a portion of this for peak resolution. The initial guess for the peak intensity, peak position are input with the help of a cursor or a mouse. Upto twenty peaks can be fitted at a time in an interval of 500 channels. For overlapping peaks, various constraints can be applied. Bragg peaks and fluorescence peaks with different half widths can be handled simultaneously. The program on execution produces a look up table which contains the refined values of the peak position, half width, peak intensity, integrated intensity, and their error estimates of each peak. The program is very general and can also be used for curve fitting of data from many other experiments. (author). 2 refs., 7 figs., 2 appendices

  11. A pseudospectral collocation time-domain method for diffractive optics

    DEFF Research Database (Denmark)

    Dinesen, P.G.; Hesthaven, J.S.; Lynov, Jens-Peter

    2000-01-01

    We present a pseudospectral method for the analysis of diffractive optical elements. The method computes a direct time-domain solution of Maxwell's equations and is applied to solving wave propagation in 2D diffractive optical elements. (C) 2000 IMACS. Published by Elsevier Science B.V. All rights...

  12. A neutron powder diffraction study of deuterated α-resorcinol: a test of profile refinement using TLS constraints

    International Nuclear Information System (INIS)

    Bacon, G.E.; Lisher, E.J.

    1979-01-01

    Constrained TL, TLX and TLS refinements have been used, with the powder-profile method, in the analysis of accurate neutron powder data for deuterated α-resorcinol at room temperature. There is good agreement between the translational and librational parameters derived from the TL refinement and those obtained from an equivalent analysis of accurate single-crystal neutron measurements. The fine details of the benzene ring are lost in the powder analysis, but the molecular orientation and the OH bond angles are in good agreement with the single-crystal values. No significant improvement could be found in the powder fit by applying the full TLS theory and, therefore, the approximate TLX model appears to be adequate for powder data. (Auth.)

  13. High-resolution inelastic neutron scattering and neutron powder diffraction study of the adsorption of dihydrogen by the Cu(II) metal-organic framework material HKUST-1

    Science.gov (United States)

    Callear, Samantha K.; Ramirez-Cuesta, Anibal J.; David, William I. F.; Millange, Franck; Walton, Richard I.

    2013-12-01

    We present new high-resolution inelastic neutron scattering (INS) spectra (measured using the TOSCA and MARI instruments at ISIS) and powder neutron diffraction data (measured on the diffractometer WISH at ISIS) from the interaction of the prototypical metal-organic framework HKUST-1 with various dosages of dihydrogen gas. The INS spectra show direct evidence for the sequential occupation of various distinct sites for dihydrogen in the metal-organic framework, whose population is adjusted during increasing loading of the guest. The superior resolution of TOSCA reveals subtle features in the spectra, not previously reported, including evidence for split signals, while complementary spectra recorded on MARI present full information in energy and momentum transfer. The analysis of the powder neutron patterns using the Rietveld method shows a consistent picture, allowing the crystallographic indenisation of binding sites for dihydrogen, thus building a comprehensive picture of the interaction of the guest with the nanoporous host.

  14. The stoichiometry of synthetic alunite as a function of hydrothermal aging investigated by solid-state NMR spectroscopy, powder X-ray diffraction and infrared spectroscopy

    DEFF Research Database (Denmark)

    Grube, Elisabeth; Nielsen, Ulla Gro

    2015-01-01

    The stoichiometry of a series of synthetic alunite (nominally KAl3(SO4)2(OH)6) samples prepared by hydrothermal methods as a function of reaction time (1 – 31 days) has been investigated by powder X-ray diffraction, Fourier transform infrared spectroscopy as well as solid-state 1H and 27Al magic...... of potassium defects present, from 17.261(1) to 17.324(5) Å. Solid-state 27Al MAS NMR revealed a decrease in the defect concentration as a function of time and showed the presence of 7-10 % impurities in the samples....

  15. Experimental method for testing diffraction properties of reflection waveguide holograms.

    Science.gov (United States)

    Xie, Yi; Kang, Ming-Wu; Wang, Bao-Ping

    2014-07-01

    Waveguide holograms' diffraction properties include peak wavelength and diffraction efficiency, which play an important role in determining their display performance. Based on the record and reconstruction theory of reflection waveguide holograms, a novel experimental method for testing diffraction properties is introduced and analyzed in this paper, which uses a plano-convex lens optically contacted to the surface of the substrate plate of the waveguide hologram, so that the diffracted light beam can be easily detected. Then an experiment is implemented. The designed reconstruction wavelength of the test sample is 530 nm, and its diffraction efficiency is 100%. The experimental results are a peak wavelength of 527.7 nm and a diffraction efficiency of 94.1%. It is shown that the tested value corresponds well with the designed value.

  16. Final Report for X-ray Diffraction Sample Preparation Method Development

    Energy Technology Data Exchange (ETDEWEB)

    Ely, T. M. [Hanford Site (HNF), Richland, WA (United States); Meznarich, H. K. [Hanford Site (HNF), Richland, WA (United States); Valero, T. [Hanford Site (HNF), Richland, WA (United States)

    2018-01-30

    WRPS-1500790, “X-ray Diffraction Saltcake Sample Preparation Method Development Plan/Procedure,” was originally prepared with the intent of improving the specimen preparation methodology used to generate saltcake specimens suitable for XRD-based solid phase characterization. At the time that this test plan document was originally developed, packed powder in cavity supports with collodion binder was the established XRD specimen preparation method. An alternate specimen preparation method less vulnerable, if not completely invulnerable to preferred orientation effects, was desired as a replacement for the method.

  17. Characterization of cubic ceria?zirconia powders by X-ray diffraction and vibrational and electronic spectroscopy

    Science.gov (United States)

    Sánchez Escribano, Vicente; Fernández López, Enrique; Panizza, Marta; Resini, Carlo; Gallardo Amores, José Manuel; Busca, Guido

    2003-10-01

    The X-ray diffraction (XRD) patterns and the Infrared, Raman and UV-visible spectra of CeO 2ZrO 2 powders prepared by co-precipitation are presented. Raman spectra provide evidence for the largely predominant cubic structure of the powders with CeO 2 molar composition higher than 25%. Also skeletal IR spectra allow to distinguish cubic from tetragonal phases which are instead not easily distinguished on the basis of the XRD patterns. All mixed oxides including pure ceria are strong UV absorbers although also absorb in the violet visible region. By carefully selecting their composition and treatment temperature, the onset of the radiation that they cut off can be chosen in the 425-475 nm interval. Although they are likely metastable, the cubic phases are still pure even after heating at 1173 K for 4 h.

  18. Structural studies of carbon nanotubes by powder x-ray diffraction at SPring-8 and KEK PF

    CERN Document Server

    Maniwa, Y; Fujiwara, A

    2003-01-01

    Powder X-ray diffraction (XRD) studies on carbon nanotubes (CNTs) using synchrotron radiation are reported. In spite of the observed broad XRD peak profiles of two-dimensional triangular (hexagonal) lattice of single-wall carbon nanotubes (SWNTs), it was shown that useful structural information, such as the tube diameter and its distribution, can be deduced from detailed analysis of the characteristic XRD patterns. In particular, powder-XRD measurements were performed to study the phase transition of encapsulated materials inside SWNTs. In the C sub 7 sub 0 -one dimensional (1D) crystals formed inside SWNTs, importance of one-dimensionality in the C sub 7 sub 0 -molecular dynamics was suggested. It was also shown that water inside SWNTs undergoes a phase transition from liquid to an ice-nanotube structure below -38degC. Conversion process from SWNT to double-wall carbon nanotube (DWNT) was also studied by XRD.

  19. NiTiO3 powders obtained by polymeric precursor method: Synthesis and characterization

    International Nuclear Information System (INIS)

    Lopes, K.P.; Cavalcante, L.S.; Simoes, A.Z.; Varela, J.A.; Longo, E.; Leite, E.R.

    2009-01-01

    Nickel titanate (NiTiO 3 ) powders were synthesized by the polymeric precursor method after thermal treatment at different temperatures for 2 h in air atmosphere. The decomposition of the precursors was monitored by differential scanning calorimetry and thermogravimetric analysis. The NiTiO 3 powders presented a reduction in the specific surface area and increase of the average particle size with the evolution of the temperature. The structural evolution of NiTiO 3 phase was accompanied by X-ray diffraction and Fourier transform Raman spectroscopy. By scanning electron microscopy was revealed the agglomerated nature of very fine particles of NiTiO 3 powders annealed from 600 to 1000 deg. C

  20. A method of combining STEM image with parallel beam diffraction and electron-optical conditions for diffractive imaging

    International Nuclear Information System (INIS)

    He Haifeng; Nelson, Chris

    2007-01-01

    We describe a method of combining STEM imaging functionalities with nanoarea parallel beam electron diffraction on a modern TEM. This facilitates the search for individual particles whose diffraction patterns are needed for diffractive imaging or structural studies of nanoparticles. This also lays out a base for 3D diffraction data collection

  1. Sample cell for powder x-ray diffraction at up to 500 bars and 200 deg. C

    International Nuclear Information System (INIS)

    Jupe, Andrew C.; Wilkinson, Angus P.

    2006-01-01

    A low cost sample cell for powder diffraction at high pressure and temperature that employs either sapphire or steel pressure tubes is described. The cell can be assembled rapidly, facilitating the study of chemically reacting systems, and it provides good control of both pressure and temperature in a regimen where diamond anvil cells and multianvil apparatus cannot be used. The design provides a relatively large sample volume making it suitable for the study of quite large grain size materials, such as hydrating cement slurries. However, relatively high energy x rays are needed to penetrate the pressure tube

  2. Structural study of Sr{sub 2}CuO{sub 3+delta} by neutron powder diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Shimakawa, Y. [NEC Corp., Tsukuba (Japan). Fundamental Research Labs.; Jorgensen, J.D.; Mitchell, J.F.; Hunter, B.A. [Argonne National Lab., IL (United States); Shaked, S. [Israel Atomic Energy Commission, Beersheba (Israel). Nuclear Research Center-Negev][Ben-Gurion Univ. of the Negev, Beersheba (Israel). Dept. of Physics; Hinks, D.G.; Hitterman, R.L. [Argonne National Lab., IL (United States); Hiroi, Z.; Takano, M. [Kyoto Univ., Uji (Japan). Inst. for Chemical Research

    1996-11-01

    Average crystal structures of superconducting Sr{sub 2}CuO{sub 3+{delta}} synthesized at ambient pressure from a hydroxometallate precursor were refined from neutron powder diffraction data. A simplified model was used to fit the modulated superstructures. Both compounds have an oxygen deficient La{sub 2}CuO{sub 4}-type tetragonal T structure with O vacancies located in the CuO{sub 2} planes, not in the Sr{sub 2}O{sub 2} layers. This raises important questions about the superconductivity in Sr{sub 2}CuO{sub 3+{delta}} reported to be a 70 K superconductor.

  3. A program for the derivation of crystal unit cell parameters from X-ray powder diffraction measurements

    International Nuclear Information System (INIS)

    Ferguson, I.F.; Rogerson, A.H.

    1984-01-01

    The program, FIRESTAR, determines the dimensions of a crystallographic unit cell from a set of X-ray powder diffraction measurements corresponding to a set of Bragg reflections, provided that the crystal system applicable is known and the Bragg reflections have been indexed. The program includes a range of possible extrapolation functions, and the data may be weighted. Provision is made for detecting and rejecting a single 'bad' measurement, and then rejecting measurements which lie outside an error limit set in the input data. (orig.)

  4. Ternary ceramic thermal spraying powder and method of manufacturing thermal sprayed coating using said powder

    Energy Technology Data Exchange (ETDEWEB)

    Vogli, Evelina; Sherman, Andrew J.; Glasgow, Curtis P.

    2018-02-06

    The invention describes a method for producing ternary and binary ceramic powders and their thermal spraying capable of manufacturing thermal sprayed coatings with superior properties. Powder contain at least 30% by weight ternary ceramic, at least 20% by weight binary molybdenum borides, at least one of the binary borides of Cr, Fe, Ni, W and Co and a maximum of 10% by weight of nano and submicro-sized boron nitride. The primary crystal phase of the manufactured thermal sprayed coatings from these powders is a ternary ceramic, while the secondary phases are binary ceramics. The coatings have extremely high resistance against corrosion of molten metal, extremely thermal shock resistance and superior tribological properties at low and at high temperatures.

  5. A novel isomorphic phase transition in β-pyrochlore oxide KOs2O6: a study using high resolution neutron powder diffraction

    Science.gov (United States)

    Sasai, Kenzo; Kofu, Maiko; Ibberson, Richard M.; Hirota, Kazuma; Yamaura, Jun-ichi; Hiroi, Zenji; Yamamuro, Osamu

    2010-01-01

    We have carried out adiabatic calorimetric and neutron powder diffraction experiments on the β-pyrochlore oxide KOs2O6, which has a superconducting transition at Tc = 9.6 K and another novel transition at Tp = 7.6 K. A characteristic feature of this compound is that the K ions exhibit rattling vibrations in the cages formed by O atoms even at very low temperatures. The temperature and entropy of the Tp transition is in good agreement with previous data measured using a heat relaxation method, indicating that the present sample is of high purity and the transition entropy, 0.296 J K-1 mol-1, does not depend on the calorimetric method used. The neutron powder diffraction data show no peak splitting nor extra peaks over the temperature range between 2 and 295 K, suggesting that the Tp transition is a rather unusual isomorphic transition. Rietveld analysis revealed an anomalous expansion of the lattice and a deformation of the O atom cage below 7.6 K. In the low-temperature phase, the distribution of scattering density corresponding to the K ions becomes broader whilst maintaining its maximum at the cage center. Based on these findings, we suggest that the Tp transition is due to the expansion of the cage volume and cooperative condensation of the K ions into the ground state of the rattling motion.

  6. Structure of orthorhombic SrZrO/sub 3/ by neutron powder diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Ahtee, A; Ahtee, M [Helsinki Univ. (Finland). Dept. of Physics; Glazer, A M [Cambridge Univ. (UK). Cavendish Lab.; Hewat, A W [Institut Max von Laue - Paul Langevin, 38 - Grenoble (France)

    1976-12-15

    The room-temperature structure of SrZrO/sub 3/ has been established by neutron powder-profile refinement. The space group is Pbnm and SrZrO/sub 3/ is isostructural with other perovskites, such as CaTiO/sub 3/.

  7. Synthesis of nanostructured LiTi2(PO4)3 powder by a Pechini-type polymerizable complex method

    International Nuclear Information System (INIS)

    Mariappan, C.R.; Galven, C.; Crosnier-Lopez, M.-P.; Le Berre, F.; Bohnke, O.

    2006-01-01

    The nanostructured NASICON-type LiTi 2 (PO 4 ) 3 (LTP) material has been synthesized by Pechini-type polymerizable complex method. The use of water-soluble ammonium citratoperoxotitanate (IV) metal complex instead of alkoxides as precursor allows to prepare monophase material. Thermal analyses have been carried out on the powder precursor to check the weight loss and synthesis temperature. X-ray powder diffraction analysis (XRD) has been performed on the LTP powder obtained after heating the powder precursor over a temperature range from 550 to 1050 deg. C for 2 h. By varying the molar ratio of citric acid to metal ion (CA/Ti) and citric acid to ethylene glycol (CA/EG), the grain size of the LTP powder could be modified. The formation of small and well-crystalline grains, in the order of 50-125 nm in size, has been determined from the XRD patterns and confirmed by transmission electron microscopy

  8. High-resolution inelastic neutron scattering and neutron powder diffraction study of the adsorption of dihydrogen by the Cu(II) metal–organic framework material HKUST-1

    Energy Technology Data Exchange (ETDEWEB)

    Callear, Samantha K.; Ramirez-Cuesta, Anibal J.; David, William I.F. [ISIS Facility, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, OX11 0QX (United Kingdom); Millange, Franck [Institut Lavoisier Versailles (CNRS UMR 8180), Université de Versailles, 78035 Versailles (France); Walton, Richard I., E-mail: r.i.walton@warwick.ac.uk [Department of Chemistry, University of Warwick, CV4 7AL, Coventry (United Kingdom)

    2013-12-12

    Highlights: • Binding sites for dihydrogen in a metal–organic framework have been identified. • The combination of diffraction and spectroscopy shows competitive filling of various adsorption sites. • Inelastic neutron scattering over wide-momentum transfer reveals new models for hydrogen-framework interactions. - Abstract: We present new high-resolution inelastic neutron scattering (INS) spectra (measured using the TOSCA and MARI instruments at ISIS) and powder neutron diffraction data (measured on the diffractometer WISH at ISIS) from the interaction of the prototypical metal–organic framework HKUST-1 with various dosages of dihydrogen gas. The INS spectra show direct evidence for the sequential occupation of various distinct sites for dihydrogen in the metal–organic framework, whose population is adjusted during increasing loading of the guest. The superior resolution of TOSCA reveals subtle features in the spectra, not previously reported, including evidence for split signals, while complementary spectra recorded on MARI present full information in energy and momentum transfer. The analysis of the powder neutron patterns using the Rietveld method shows a consistent picture, allowing the crystallographic indenisation of binding sites for dihydrogen, thus building a comprehensive picture of the interaction of the guest with the nanoporous host.

  9. High-resolution inelastic neutron scattering and neutron powder diffraction study of the adsorption of dihydrogen by the Cu(II) metal–organic framework material HKUST-1

    International Nuclear Information System (INIS)

    Callear, Samantha K.; Ramirez-Cuesta, Anibal J.; David, William I.F.; Millange, Franck; Walton, Richard I.

    2013-01-01

    Highlights: • Binding sites for dihydrogen in a metal–organic framework have been identified. • The combination of diffraction and spectroscopy shows competitive filling of various adsorption sites. • Inelastic neutron scattering over wide-momentum transfer reveals new models for hydrogen-framework interactions. - Abstract: We present new high-resolution inelastic neutron scattering (INS) spectra (measured using the TOSCA and MARI instruments at ISIS) and powder neutron diffraction data (measured on the diffractometer WISH at ISIS) from the interaction of the prototypical metal–organic framework HKUST-1 with various dosages of dihydrogen gas. The INS spectra show direct evidence for the sequential occupation of various distinct sites for dihydrogen in the metal–organic framework, whose population is adjusted during increasing loading of the guest. The superior resolution of TOSCA reveals subtle features in the spectra, not previously reported, including evidence for split signals, while complementary spectra recorded on MARI present full information in energy and momentum transfer. The analysis of the powder neutron patterns using the Rietveld method shows a consistent picture, allowing the crystallographic indenisation of binding sites for dihydrogen, thus building a comprehensive picture of the interaction of the guest with the nanoporous host

  10. Combined Approach for the Structural Characterization of Alkali Fluoroscandates: Solid-State NMR, Powder X-ray Diffraction, and Density Functional Theory Calculations.

    Science.gov (United States)

    Rakhmatullin, Aydar; Polovov, Ilya B; Maltsev, Dmitry; Allix, Mathieu; Volkovich, Vladimir; Chukin, Andrey V; Boča, Miroslav; Bessada, Catherine

    2018-02-05

    The structures of several fluoroscandate compounds are presented here using a characterization approach combining powder X-ray diffraction and solid-state NMR. The structure of K 5 Sc 3 F 14 was fully determined from Rietveld refinement performed on powder X-ray diffraction data. Moreover, the local structures of NaScF 4 , Li 3 ScF 6 , KSc 2 F 7 , and Na 3 ScF 6 compounds were studied in detail from solid-state 19 F and 45 Sc NMR experiments. The 45 Sc chemical shift ranges for six- and seven-coordinated scandium environments were defined. The 19 F chemical shift ranges for bridging and terminal fluorine atoms were also determined. First-principles calculations of the 19 F and 45 Sc NMR parameters were carried out using plane-wave basis sets and periodic boundary conditions (CASTEP), and the results were compared with the experimental data. A good agreement between the calculated shielding constants and experimental chemical shifts was obtained. This demonstrates the good potential of computational methods in spectroscopic assignments of solid-state 45 Sc NMR spectroscopy.

  11. Study on mineral components of rat calvaria by means of X-ray powder diffraction analysis and Raman microprobe spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Tamura, Norihiro [Meikai Univ., Sakado, Saitama (Japan). School of Dentistry

    2000-07-01

    The present study was designed to examine the occurrence of the precursor minerals of hydroxyapatite (HA) during the process of HA formation in the rat calvaria. Dried and powdered rat calvaria and synthetic samples, such as HA, dicalcium phosphate dihydrate (DCPD), octacalcium phosphate (OCP), ({beta}-calcium pyrophosphate) and ({beta}-tricalcium phosphate), were used. Determinations were carried out by X-ray powder diffraction and Raman microprobe spectrometry. In general, significant widening of the diffraction peaks was shown to occur after the plasma ashing was performed for the X-ray diffraction. As a result, two adjacent peaks seen normally in the diffraction angles (2 {theta}) 30-35 deg, which is a characteristic feature of HA, were found to fuse with each other, forming a widened single peak. Also, there was a tendency for the intensity of the diffraction peaks to increase with age. With regard to the effect of plasma ashing on the crystallograms of synthetic specimens, all specimens manifested sharp peak patterns except DCPD and OCP. In contrast, a widening of diffraction peaks was observed in the DCPD and OCP samples, indicating that crystallinity had changed during the pretreatment. Results obtained from both vital and synthetic samples after heat treatment at 1000 deg C were as follow: Clearcut diffraction patterns, characteristics of HA, were obtained in all of the calvaria samples. Further, {beta}-TCP was produced by heat treatment of OCP, and its pattern was detected in the samples from rats younger than 6 days of age. Amounts of {beta}-TCP in percentage were disclosed to be 40.2% in embryonal samples, 28.4% in newborn samples, and 18.6% in 6-day-old samples. But no {beta}-TCP could be detected in the 12-week-old samples, indicating that the amount of {beta}-TCP in calvaria decreased with age. We also found that ashing pretreatment did not cause any changes in the samples of HA, {beta}-CPP, and {beta}-TCP. Further, DCPD and {beta}-CPP samples shared

  12. Study on mineral components of rat calvaria by means of X-ray powder diffraction analysis and Raman microprobe spectroscopy

    International Nuclear Information System (INIS)

    Tamura, Norihiro

    2000-01-01

    The present study was designed to examine the occurrence of the precursor minerals of hydroxyapatite (HA) during the process of HA formation in the rat calvaria. Dried and powdered rat calvaria and synthetic samples, such as HA, dicalcium phosphate dihydrate (DCPD), octacalcium phosphate (OCP), (β-calcium pyrophosphate) and (β-tricalcium phosphate), were used. Determinations were carried out by X-ray powder diffraction and Raman microprobe spectrometry. In general, significant widening of the diffraction peaks was shown to occur after the plasma ashing was performed for the X-ray diffraction. As a result, two adjacent peaks seen normally in the diffraction angles (2 θ) 30-35 deg, which is a characteristic feature of HA, were found to fuse with each other, forming a widened single peak. Also, there was a tendency for the intensity of the diffraction peaks to increase with age. With regard to the effect of plasma ashing on the crystallograms of synthetic specimens, all specimens manifested sharp peak patterns except DCPD and OCP. In contrast, a widening of diffraction peaks was observed in the DCPD and OCP samples, indicating that crystallinity had changed during the pretreatment. Results obtained from both vital and synthetic samples after heat treatment at 1000 deg C were as follow: Clearcut diffraction patterns, characteristics of HA, were obtained in all of the calvaria samples. Further, β-TCP was produced by heat treatment of OCP, and its pattern was detected in the samples from rats younger than 6 days of age. Amounts of β-TCP in percentage were disclosed to be 40.2% in embryonal samples, 28.4% in newborn samples, and 18.6% in 6-day-old samples. But no β-TCP could be detected in the 12-week-old samples, indicating that the amount of β-TCP in calvaria decreased with age. We also found that ashing pretreatment did not cause any changes in the samples of HA, β-CPP, and β-TCP. Further, DCPD and β-CPP samples shared the same diffraction pattern, and OCP

  13. Stress measurement by neutron diffraction method. Standard method using angular dispersion method and trial of using neutron IP

    International Nuclear Information System (INIS)

    Sasaki, Toshihiko; Takago, Shigeki

    2016-01-01

    This paper outlined a stress measurement method using neutrons, and introduced the application examples to stress measurement for metal-based composite materials. In the angular dispersion type measurement using a steady-state reactor type neutron source, the white beams taken out from a nuclear reactor are monochromatized (wavelength λ is a constant value) with a single crystal monochromator and utilized. As an example of measurement, there was the case as follows: the stress of a sintered material which has been put to practical use as valve seat part for automobiles was measured by the neutron method, and the deformation behavior during load was studied. This study performed neutron diffraction measurement using a residual stress analyzer (RESA: Diffractometer for Residual Stress Analysis) installed at JAEA's experimental reactor JRR-3. As a result, it was found that the stress state of the sintered composite material of Fe-Cr and TiN can be predicted with a micromechanics model. A neutron diffraction ring can be obtained using a neutron image plate (IP), where fine powder of gadolinium (Gd) was incorporated into IP for X-rays, and it can be used as an IP reader in the same way as the case of X-rays. A report has been introduced on the examination results of the highly accurate stress measurement by applying the cos α method devised for X-ray stress measurement to neutron diffraction ring. (A.O.)

  14. Evidence for existence of functional monoclinic phase in sodium niobate based solid solution by powder neutron diffraction

    Science.gov (United States)

    Mishra, S. K.; Jauhari, Mrinal; Mittal, R.; Krishna, P. S. R.; Reddy, V. R.; Chaplot, S. L.

    2018-04-01

    We have carried out systematic temperature-dependent neutron diffraction measurements in conjunction with dielectric spectroscopy from 6 to 300 K for sodium niobate based compounds (1-x) NaNbO3-xBaTiO3 (NNBTx). The dielectric constant is measured as a function of both temperature and frequency. It shows an anomaly at different temperatures in cooling and heating cycles and exhibits a large thermal hysteresis of ˜150 K for the composition x = 0.03. The dielectric constant is found to be dispersive in nature and suggests a relaxor ferroelectric behavior. In order to explore structural changes as a function of temperature, we analyzed the powder neutron diffraction data for the compositions x = 0.03 and 0.05. Drastic changes are observed in the powder profiles near 2θ ˜ 30.6°, 32.1°, and 34.6° in the diffraction pattern below 200 K during cooling and above 190 K in heating cycles, respectively. The disappearance of superlattice reflection and splitting in main perovskite peaks provide a signature for structural phase transition. We observed stabilization of a monoclinic phase (Cc) at low temperature. This monoclinic phase is believed to provide a flexible polarization rotation and considered to be directly linked to the high performance piezoelectricity in materials. The thermal hysteresis for composition x = 0.03 is larger than that for x = 0.05. This suggests that the addition of BaTiO3 to NaNbO3 suppresses the thermal hysteresis. It is also observed that the structural phase transition temperature decreases upon increasing the dopant concentration.

  15. Neutron diffraction measurements of residual stress in a powder metallurgy component

    International Nuclear Information System (INIS)

    Schneider, L.C.R.; Hainsworth, S.V.; Cocks, A.C.F.; Fitzpatrick, M.E.

    2005-01-01

    Residual stresses in a typical industrial green component were determined using neutron diffraction. The measured residual stresses were found to correlate with cross-sectional variations. Residual stress at the edge of the compact in contact with the die wall during compaction reached up to +80 MPa (tension) and -100 MPa (compression)

  16. A structural investigation into the compaction behavior of pharmaceutical composites using powder X-ray diffraction and total scattering analysis.

    Science.gov (United States)

    Moore, Michael D; Steinbach, Alison M; Buckner, Ira S; Wildfong, Peter L D

    2009-11-01

    To use advanced powder X-ray diffraction (PXRD) to characterize the structure of anhydrous theophylline following compaction, alone, and as part of a binary mixture with either alpha-lactose monohydrate or microcrystalline cellulose. Compacts formed from (1) pure theophylline and (2) each type of binary mixture were analyzed intact using PXRD. A novel mathematical technique was used to accurately separate multi-component diffraction patterns. The pair distribution function (PDF) of isolated theophylline diffraction data was employed to assess structural differences induced by consolidation and evaluated by principal components analysis (PCA). Changes induced in PXRD patterns by increasing compaction pressure were amplified by the PDF. Simulated data suggest PDF dampening is attributable to molecular deviations from average crystalline position. Samples compacted at different pressures were identified and differentiated using PCA. Samples compacted at common pressures exhibited similar inter-atomic correlations, where excipient concentration factored in the analyses involving lactose. Practical real-space structural analysis of PXRD data by PDF was accomplished for intact, compacted crystalline drug with and without excipient. PCA was used to compare multiple PDFs and successfully differentiated pattern changes consistent with compaction-induced disordering of theophylline as a single component and in the presence of another material.

  17. Preliminary study of determination of UO2 grain size using X-ray diffraction method

    International Nuclear Information System (INIS)

    Mulyana, T.; Sambodo, G. D.; Juanda, D.; Fatchatul, B.

    1998-01-01

    The determination of UO 2 grain size has accomplished using x-ray diffraction method. The UO 2 powder is obtained from sol-gel process. A copper target as radiation source in the x-ray diffractometer was used in this experiment with CμKα characteristic wavelength 1.54433 Angstrom. The result indicate that the UO 2 mean grain size on presintered (temperature 800 o C) has the value 456.8500 Angstrom and the UO 2 mean grain size on sintered (temperature 1700 o C) has value 651.4934 Angstrom

  18. The high-resolution powder diffraction station PO DI STA is ''running'' at Adone

    International Nuclear Information System (INIS)

    Burattini, E.; Simeoni, S.; Cappuccio, G.; Maistrelli, P.

    1992-01-01

    At the end of February 1991, a ''triple-axis'' high-resolution diffractometer for on powder sample measurements with synchrotron radiation was put in operation on the Adone wiggler line BX1 at Frascati. The diffractometer is based on a Seifert goniometer, designed according to our specifications. During the project, particular attention was paid in assuring the highest reliability together with great flexibility in the use. In fact, the diffractometer can also be used in a ''medium resolution'' configuration. For preliminary alignment and data collection, it is possible to operate with a traditional x-ray tube, too. The alignment procedure of the diffractometer to the x-ray beam is very easy. Powder samples can be measured both on the flat holder and on the capillary. An IBM PC computer is used for the instrument actuation and preliminary on-line data collection, while a large software package has been developed for the data analysis performed by a Macintosh IIcx. The instrument performance has been tested with a standard Si sample and quartz and Ni oxide samples. For the two possible resolution configurations, a test on a NiO sample gave FWHM values of 0.16 degree and 0.04 degree, respectively, for the [012] peak

  19. X-ray mapping in heterocyclic design: IV. Crystal structure determination of 3-(p-nitrobenzoyl)-2-oxooxazolo[3,2-a]pyridine from powder diffraction data

    International Nuclear Information System (INIS)

    Rybakov, V.B.; Zhukov, S.G.; Babaev, E.V.; Sonneveld, E.J.

    2001-01-01

    The structure of 3-(p-nitrobenzoy)-2-oxooxazolo[3,2-a]pyridine is determined by the powder diffraction technique. The crystals are monoclinic, a = 13.642(2) A, b = 22.278(3) A, c = 3.917(1) A, β = 90.63(2) deg., Z 4, and space group P2 1 /n. The structure is solved by a modified Monte Carlo method and refined by the Reitveld method. The six-membered heterocycle is characterized by the alternation of partially single and partially double bonds. The system of two conjugated heterocycles is planar and forms a dihedral angle of 46.1(1) deg. with the plane of the phenyl ring. The nitro group is virtually coplanar with the phenyl fragment. An extensive system of intramolecular and intermolecular contacts involving hydrogen, oxygen, and nitrogen atoms is observed in the crystal

  20. Method for preparing a sinterable uranium dioxide powder

    International Nuclear Information System (INIS)

    Thornton, T.A.; Holaday, V.D. Jr.

    1985-01-01

    This invention provides an improved method for preparing a sinterable uranium dioxide powder for the preparation of nuclear fuel, using microwave radiation in a microwave induction furnace. The starting compound may be uranyl nitrate hexahydrate, ammonium diuranate or ammonium uranyl carbonate. The starting compound is heated in a microwave induction furnace for a period of time sufficient for compound decomposition. The decomposed compound is heated in a microwave induction furnace in a reducing atmosphere for a period of time sufficient to reduce the decomposed compound to uranium dioxide powder

  1. Method for forming biaxially textured articles by powder metallurgy

    Science.gov (United States)

    Goyal, Amit; Williams, Robert K.; Kroeger, Donald M.

    2002-01-01

    A method of preparing a biaxially textured alloy article comprises the steps of preparing a mixture comprising Ni powder and at least one powder selected from the group consisting of Cr, W, V, Mo, Cu, Al, Ce, YSZ, Y, Rare Earths, (RE), MgO, CeO.sub.2, and Y.sub.2 O.sub.3 ; compacting the mixture, followed by heat treating and rapidly recrystallizing to produce a biaxial texture on the article. In some embodiments the alloy article further comprises electromagnetic or electro-optical devices and possesses superconducting properties.

  2. Method and apparatus for the production of metal oxide powder

    Science.gov (United States)

    Harris, Michael T.; Scott, Timothy C.; Byers, Charles H.

    1992-01-01

    The present invention provides a method for preparing metal oxide powder. A first solution, which is substantially organic, is prepared. A second solution, which is an aqueous solution substantially immiscible in the first solution, is prepared and delivered as drops to the first solution. The drops of the second solution are atomized by a pulsed electric field forming micro-drops of the second solution. Reagents in the first solution diffuse into and react with reactants in the micro-drops of the second solution forming metal hydroxide or oxalate particles. The metal hydroxide or metal oxalate particles are then recovered and dried to produce the metal oxide powder. An apparatus for preparing a metal oxide powder is also disclosed.

  3. Method and apparatus for the production of metal oxide powder

    Science.gov (United States)

    Harris, M.T.; Scott, T.C.; Byers, C.H.

    1992-06-16

    The present invention provides a method for preparing metal oxide powder. A first solution, which is substantially organic, is prepared. A second solution, which is an aqueous solution substantially immiscible in the first solution, is prepared and delivered as drops to the first solution. The drops of the second solution are atomized by a pulsed electric field forming micro-drops of the second solution. Reagents in the first solution diffuse into and react with reactants in the micro-drops of the second solution forming metal hydroxide or oxalate particles. The metal hydroxide or metal oxalate particles are then recovered and dried to produce the metal oxide powder. An apparatus for preparing a metal oxide powder is also disclosed. 2 figs.

  4. Graphene oxide powders with different oxidation degree, prepared by synthesis variations of the Hummers method

    International Nuclear Information System (INIS)

    Guerrero-Contreras, Jesus; Caballero-Briones, F.

    2015-01-01

    Graphene oxide (GO) powders with different oxidation degree estimated through the relative intensity of the infrared absorption bands related to oxygen containing groups were prepared through variations of the Hummers method. The GO powders were analyzed by Transmission Electron Microscopy, Energy dispersive spectroscopy, X-ray Photoelectron Spectroscopy, Fourier Transform Infrared Spectroscopy, Raman spectroscopy, X-ray Diffraction, UV–VIS spectroscopy and Electrical Resistance measurements. Several square micron GO sheets with low wrinkling were obtained. Oxygen to carbon ratio is around 0.2 in all the samples although a strong variance in the relative intensity of the oxygen related infrared bands is evident. Thus, the oxidation degree was estimated from the FTIR measurements using the quotient between the C–O related bands area to the total area under the spectra. FTIR shows presence of hydroxyl (–OH), epoxy (C–O–C), carboxyl (–COOH) and carbonyl (C=O) moieties and evidence of intermolecular interactions between adjacent groups. These interactions influence the exfoliation degree, the absorbance of the GO suspensions, as well as the electrical resistance, while the crystalline domain sizes, estimated from XRD and Raman do not show a noticeable behavior related with the composition and molecular structure. The results indicate that the electrical resistance is influenced mainly by the surface chemistry of the GO powders and not only by the O/C ratio. The control of the surface chemistry of GO powders would allow their use as additives in organic bulk heterojunction solar cells with enhanced photoconversion efficiency. - Highlights: • Powders of graphene oxide with different oxidation degree were prepared through variations of the Hummers method. • Raman spectroscopy and XRD demonstrated similar crystallite domain size in the samples. • Electrical resistance, exfoliation degree and optical absorption depend on the molecular structure.

  5. Graphene oxide powders with different oxidation degree, prepared by synthesis variations of the Hummers method

    Energy Technology Data Exchange (ETDEWEB)

    Guerrero-Contreras, Jesus; Caballero-Briones, F., E-mail: fcaballero@ipn.mx

    2015-03-01

    Graphene oxide (GO) powders with different oxidation degree estimated through the relative intensity of the infrared absorption bands related to oxygen containing groups were prepared through variations of the Hummers method. The GO powders were analyzed by Transmission Electron Microscopy, Energy dispersive spectroscopy, X-ray Photoelectron Spectroscopy, Fourier Transform Infrared Spectroscopy, Raman spectroscopy, X-ray Diffraction, UV–VIS spectroscopy and Electrical Resistance measurements. Several square micron GO sheets with low wrinkling were obtained. Oxygen to carbon ratio is around 0.2 in all the samples although a strong variance in the relative intensity of the oxygen related infrared bands is evident. Thus, the oxidation degree was estimated from the FTIR measurements using the quotient between the C–O related bands area to the total area under the spectra. FTIR shows presence of hydroxyl (–OH), epoxy (C–O–C), carboxyl (–COOH) and carbonyl (C=O) moieties and evidence of intermolecular interactions between adjacent groups. These interactions influence the exfoliation degree, the absorbance of the GO suspensions, as well as the electrical resistance, while the crystalline domain sizes, estimated from XRD and Raman do not show a noticeable behavior related with the composition and molecular structure. The results indicate that the electrical resistance is influenced mainly by the surface chemistry of the GO powders and not only by the O/C ratio. The control of the surface chemistry of GO powders would allow their use as additives in organic bulk heterojunction solar cells with enhanced photoconversion efficiency. - Highlights: • Powders of graphene oxide with different oxidation degree were prepared through variations of the Hummers method. • Raman spectroscopy and XRD demonstrated similar crystallite domain size in the samples. • Electrical resistance, exfoliation degree and optical absorption depend on the molecular structure.

  6. Characterization of (1 1 1) surface tailored Pt nanoparticles by electrochemistry and X-ray powder diffraction

    International Nuclear Information System (INIS)

    Beyerlein, K.R.; Solla-Gullon, J.; Herrero, E.; Garnier, E.; Pailloux, F.; Leoni, M.; Scardi, P.; Snyder, R.L.; Aldaz, A.; Feliu, J.M.

    2010-01-01

    Platinum nanoparticles with a mean size of 8.7 nm were synthesized by a salt reduction reaction having polyhedron shapes with preferential (1 1 1) surfaces. In situ electrochemical characterization of nanoparticles was performed which confirmed the existence of mostly (1 1 1) surface sites in the sample. The effect of this surface in the electrooxidation of CO was measured. Debye Function Analysis (DFA) and Whole Powder Pattern Modelling (WPPM) of the measured X-ray diffraction pattern were carried out to obtain statistical information on the particle size and shape present in the sample. Both analyses determined that the octahedron particle shape was the most abundant which was also consistent with TEM observations. The existence of a small percentage of single twinned particles was determined by DFA, WPPM, as well as analysis of HRTEM images.

  7. Spiral chain structure of high pressure selenium-II' and sulfur-II from powder x-ray diffraction

    International Nuclear Information System (INIS)

    Fujihisa, Hiroshi; Yamawaki, Hiroshi; Sakashita, Mami; Yamada, Takahiro; Honda, Kazumasa; Akahama, Yuichi; Kawamura, Haruki; Le Bihan, Tristan

    2004-01-01

    The structure of high pressure phases, selenium-II ' (Se-II ' ) and sulfur-II (S-II), for α-Se 8 (monoclinic Se-I) and α-S 8 (orthorhombic S-I) was studied by powder x-ray diffraction experiments. Se-II ' and S-II were found to be isostructural and to belong to the tetragonal space group I4 1 /acd, which is made up of 16 atoms in the unit cell. The structure consisted of unique spiral chains with both 4 1 and 4 3 screws. The results confirmed that the structure sequence of the pressure-induced phase transitions for the group VIb elements depended on the initial molecular form. The chemical bonds of the phases are also discussed from the interatomic distances that were obtained

  8. High-temperature dehydration of talc: a kinetics study using in situ X-ray powder diffraction

    Science.gov (United States)

    Wang, Duojun; Yi, Li; Huang, Bojin; Liu, Chuanjiang

    2015-06-01

    High-temperature in situ X-ray powder diffraction patterns were used to study the dehydration kinetics of natural talc with a size of 10-15 µm. The talc was annealed from 1073 to 1223 K, and the variations in the characteristic peaks corresponding to talc with the time were recorded to determine the reaction progress. The decomposition of talc occurred, and peaks corresponding to talc and peaks corresponding to enstatite and quartz were observed. The enstatite and talc exhibited a topotactic relationship. The dehydration kinetics of talc was studied as a function of temperature between 1073 and 1223 K. The kinetics data could be modeled using an Avrami equation that considers nucleation and growth processes ? where n varies from 0.4 to 0.8. The rate constant (k) equation for the natural talc is ? The reaction mechanism for the dehydration of talc is a heterogeneous nucleation and growth mechanism.

  9. Structures of Bi14WO24 and Bi14MoO24 from neutron powder diffraction data

    International Nuclear Information System (INIS)

    Ling, C.D.; Withers, R.L.; Thompson, J.G.; Schmid, S.

    1999-01-01

    The (isomorphous) structures of Bi 14 WO 24 , tetradecabismuth tungsten tetracosaoxide, and Bi 14 MoO 24 , tetradecabismuth molybdenum tetracosaoxide, have been solved and refined using neutron powder diffraction data in the space group I4/m. The metal-atom array is fully ordered in terms of composition, and in terms of atomic positions deviates only slightly from a fluorite-type δ-Bi 2 O 3 -related parent structure. Three independent O-atom sites (accounting for 70 out of 78 O atoms in the unit cell) are also very close to fluorite-type parent positions. The remaining two O-atom sites, which coordinate W, exhibit partial occupancies and displacive disorder, neither of which could be better modelled by lowering of symmetry. The W site is coordinated by four O atoms in highly distorted tetrahedral coordination, the tetrahedron necessarily being orientationally disordered on that site. Nonetheless, the structure appears to be chemically reasonable. (orig.)

  10. Neutron powder diffraction study of nuclear and magnetic structures of oxidized and reduced YBa2Fe3O8+w

    International Nuclear Information System (INIS)

    Karen, P.; Kjekshus, A.; Huang, Q.; Karen, V.L.; Lynn, J.W.; Rosov, N.; Natali Sora, I.; Santoro, A.

    2003-01-01

    YBa 2 Fe 3 O 8+w has been investigated by neutron powder diffraction as function of temperature and oxygen nonstoichiometry close to the limits of the homogeneity range, -0.24 0) in the structural layers of Y, or by creating oxygen vacancies (w 2 Cu 3 O 6+w' upon oxidation. The effects of nonstoichiometry on these related crystal structures are discussed in terms of bond-valence sums. The cooperative magnetic structure for all compositions is based on a larger cell related to the nuclear cell by the transformation matrix (11-bar0/110/002), having orthorhombic symmetry when the nuclear structure is tetragonal and monoclinic symmetry when the nuclear structure is orthorhombic. The iron moments are coupled antiferromagnetically in all three directions, the Neel temperature is almost constant as a function of w (T N ∼660 K), and so is also the low-temperature saturation moment μ AF ∼4.0μ B

  11. Profiling pleural effusion cells by a diffraction imaging method

    Science.gov (United States)

    Al-Qaysi, Safaa; Hong, Heng; Wen, Yuhua; Lu, Jun Q.; Feng, Yuanming; Hu, Xin-Hua

    2018-02-01

    Assay of cells in pleural effusion (PE) is an important means of disease diagnosis. Conventional cytology of effusion samples, however, has low sensitivity and depends heavily on the expertise of cytopathologists. We applied a polarization diffraction imaging flow cytometry method on effusion cells to investigate their features. Diffraction imaging of the PE cell samples has been performed on 6000 to 12000 cells for each effusion cell sample of three patients. After prescreening to remove images by cellular debris and aggregated non-cellular particles, the image textures were extracted with a gray level co-occurrence matrix (GLCM) algorithm. The distribution of the imaged cells in the GLCM parameters space was analyzed by a Gaussian Mixture Model (GMM) to determine the number of clusters among the effusion cells. These results yield insight on textural features of diffraction images and related cellular morphology in effusion samples and can be used toward the development of a label-free method for effusion cells assay.

  12. X-ray powder diffraction camera for high-field experiments

    International Nuclear Information System (INIS)

    Koyama, K; Mitsui, Y; Takahashi, K; Watanabe, K

    2009-01-01

    We have designed a high-field X-ray diffraction (HF-XRD) camera which will be inserted into an experimental room temperature bore (100 mm) of a conventional solenoid-type cryocooled superconducting magnet (10T-CSM). Using the prototype camera that is same size of the HF-XRD camera, a XRD pattern of Si is taken at room temperature in a zero magnetic field. From the obtained results, the expected ability of the designed HF-XRD camera is presented.

  13. About some practical aspects of X-ray diffraction : From single crystal to powders

    Energy Technology Data Exchange (ETDEWEB)

    Giacovazzo, C [Bari Univ. (Italy). Dip. Geomineralogico

    1996-09-01

    An ideal polycrystalline material or power is an ensemble of a very large number of randomly oriented crystallites. It is shown the effect that this random orientation has on the diffraction of a specimen assumed to contain only one reciprocal lattice node. The most remarkable difference with the single-crystal case is that now must think of scattering vectors not as lying on discrete nodes of reciprocal lattice vectors, the distances from the single-crystal reciprocal lattice nodes to the origin of reciprocal space.

  14. About some practical aspects of X-ray diffraction : From single crystal to powders

    International Nuclear Information System (INIS)

    Giacovazzo, C.

    1996-01-01

    An ideal polycrystalline material or power is an ensemble of a very large number of randomly oriented crystallites. It is shown the effect that this random orientation has on the diffraction of a specimen assumed to contain only one reciprocal lattice node. The most remarkable difference with the single-crystal case is that now must think of scattering vectors not as lying on discrete nodes of reciprocal lattice vectors, the distances from the single-crystal reciprocal lattice nodes to the origin of reciprocal space

  15. Solid state characterization and crystal structure from X-ray powder diffraction of two polymorphic forms of ranitidine base.

    Science.gov (United States)

    de Armas, Héctor Novoa; Peeters, Oswald M; Blaton, Norbert; Van Gyseghem, Elke; Martens, Johan; Van Haele, Gerrit; Van Den Mooter, Guy

    2009-01-01

    Ranitidine hydrochloride (RAN-HCl), a known anti-ulcer drug, is the product of reaction between HCl and ranitidine base (RAN-B). RAN-HCl has been extensively studied; however this is not the case of the RAN-B. The solid state characterization of RAN-B polymorphs has been carried out using different analytical techniques (microscopy, thermal analysis, Fourier transform infrared spectrometry in the attenuated total reflection mode, (13)C-CPMAS-NMR spectroscopy and X-ray powder diffraction). The crystal structures of RAN-B form I and form II have been determined using conventional X-ray powder diffraction in combination with simulated annealing and whole profile pattern matching, and refined using rigid-body Rietveld refinement. RAN-B form I is a monoclinic polymorph with cell parameters: a = 7.317(2), b = 9.021(2), c = 25.098(6) A, beta = 95.690(1) degrees and space group P2(1)/c. The form II is orthorhombic: a = 31.252(4), b = 13.052(2), c = 8.0892(11) A with space group Pbca. In RAN-B polymorphs, the nitro group is involved in a strong intramolecular hydrogen bond responsible for the existence of a Z configuration in the enamine portion of the molecules. A tail to tail packing motif can be denoted via intermolecular hydrogen bonds. The crystal structures of RAN-B forms are compared to those of RAN-HCl polymorphs. RAN-B polymorphs are monotropic polymorphic pairs. (c) 2008 Wiley-Liss, Inc. and the American Pharmacists Association

  16. Validation of molecular crystal structures from powder diffraction data with dispersion-corrected density functional theory (DFT-D).

    Science.gov (United States)

    van de Streek, Jacco; Neumann, Marcus A

    2014-12-01

    In 2010 we energy-minimized 225 high-quality single-crystal (SX) structures with dispersion-corrected density functional theory (DFT-D) to establish a quantitative benchmark. For the current paper, 215 organic crystal structures determined from X-ray powder diffraction (XRPD) data and published in an IUCr journal were energy-minimized with DFT-D and compared to the SX benchmark. The on average slightly less accurate atomic coordinates of XRPD structures do lead to systematically higher root mean square Cartesian displacement (RMSCD) values upon energy minimization than for SX structures, but the RMSCD value is still a good indicator for the detection of structures that deserve a closer look. The upper RMSCD limit for a correct structure must be increased from 0.25 Å for SX structures to 0.35 Å for XRPD structures; the grey area must be extended from 0.30 to 0.40 Å. Based on the energy minimizations, three structures are re-refined to give more precise atomic coordinates. For six structures our calculations provide the missing positions for the H atoms, for five structures they provide corrected positions for some H atoms. Seven crystal structures showed a minor error for a non-H atom. For five structures the energy minimizations suggest a higher space-group symmetry. For the 225 SX structures, the only deviations observed upon energy minimization were three minor H-atom related issues. Preferred orientation is the most important cause of problems. A preferred-orientation correction is the only correction where the experimental data are modified to fit the model. We conclude that molecular crystal structures determined from powder diffraction data that are published in IUCr journals are of high quality, with less than 4% containing an error in a non-H atom.

  17. Cation-dependent anomalous compression of gallosilicate zeolites with CGS topology: A high-pressure synchrotron powder diffraction study

    International Nuclear Information System (INIS)

    Lee, Yongjae; Lee, Hyun-Hwi; Lee, Dong Ryeol; Kim, Sun Jin; Kao, Chi-chang

    2008-01-01

    The high-pressure compression behaviour of 3 different cation forms of gallosilicate zeolite with CGS topology has been investigated using in situ synchrotron X-ray powder diffraction and a diamond-anvil cell technique. Under hydrostatic conditions mediated by a nominally penetrating pressure-transmitting medium, unit-cell lengths and volume compression is modulated by different degrees of pressure-induced hydration and accompanying channel distortion. In a Na-exchanged CGS (Na 10 Ga 10 Si 22 O 64 .16H 2 O), the unit-cell volume expands by ca. 0.6% upon applying hydrostatic pressure to 0.2 GPa, whereas, in an as-synthesized K-form (K 10 Ga 10 Si 22 O 64 .5H 2 O), this initial volume expansion is suppressed to ca. 0.1% at 0.16 GPa. In the early stage of hydrostatic compression below ∼1 GPa, relative decrease in the ellipticity of the non-planar 10-rings is observed, which is then reverted to a gradual increase in the ellipticity at higher pressures above ∼1 GPa, implying a change in the compression mechanism. In a Sr-exchanged sample (Sr 5 Ga 10 Si 22 O 64 .19H 2 O), on the other hand, no initial volume expansion is observed. Instead, a change in the slope of volume contraction is observed near 1.5 GPa, which leads to a 2-fold increase in the compressibility. This is interpreted as pressure-induced rearrangement of water molecules to facilitate further volume contraction at higher pressures. - Graphical abstract: Three different cation forms of gallosilicate CGS zeolites have been investigated using synchrotron X-ray powder diffraction and a diamond-anvil cell. Under hydrostatic conditions, unit-cell lengths and volume show anomalous compression behaviours depending on the non-framework cation type and initial hydration level, which implies different modes of pressure-induced hydration and channel distortion

  18. Preparation and Crystal Structures of Some AIVB2IIO4 Compounds: Powder X-Ray Diffraction and Rietveld Analysis

    Directory of Open Access Journals (Sweden)

    K. Jeyadheepan

    2014-01-01

    Full Text Available The AIVB2IIO4 compounds such as cadmium tin oxide (Cd2SnO4 or CTO and zinc tin oxide (Zn2SnO4 or ZTO are synthesized by solid state reaction of the subsequent binary oxides. The synthesized powders were analyzed through the powder X-ray diffraction (PXRD. Cell search done on the PXRD patterns shows that the Cd2SnO4 crystallizes in orthorhombic structure with space group Pbam and the cell parameters as a=5.568(2 Å, b=9.894(3 Å, and c=3.193(1 Å and the Zn2SnO4 crystallizes as cubic with the space group Fd3 -m and with the cell parameter a=8.660(2 Å. Rietveld refinement was done on the PXRD patterns to get the crystal structure of the Cd2SnO4 and Zn2SnO4 and to define the site deficiency of atoms which causes the electrical properties of the materials.

  19. Solid-state structural properties of 2,4,6-trimethoxybenzene derivatives, determined directly from powder X-ray diffraction data in conjunction with other techniques

    International Nuclear Information System (INIS)

    Pan Zhigang; Xu Mingcan; Cheung, Eugene Y.; Platts, James A.; Harris, Kenneth D.M.; Constable, Edwin C.; Housecroft, Catherine E.

    2006-01-01

    Structural properties of 2,4,6-trimethoxybenzaldehyde, 2,4,6-trimethoxybenzyl alcohol and 2,4,6-trimethoxyacetophenone have been determined directly from powder X-ray diffraction data, using the direct-space Genetic Algorithm (GA) technique for structure solution followed by Rietveld refinement. Structural similarities and contrasts within this family of materials are elucidated. The work illustrates the value of utilizing information from other sources, including spectroscopic data and computational techniques, as a means of augmenting the structural knowledge established from the powder X-ray diffraction data

  20. Thermal and structural study of guava (Psidium guajava L powders obtained by two dehydration methods

    Directory of Open Access Journals (Sweden)

    Coralia Osorio

    2011-01-01

    Full Text Available Two food products (powders were obtained by hot-air drying or lyophilisation methods on the whole guava fruits. The powders were characterised by sensory and thermal analyses (TGA-DSC, infrared spectroscopy (IR, X-ray diffraction (XRD and scanning electron microscopy (SEM. Thermal, morphological and structural characterisations showed a similar behaviour for the two solids. TGA-DSC and IR showed the presence of pectin as the main constituent of solids. A semi-crystalline profile was evidenced by XRD, and lamellar/spherical morphologies were observed by SEM. Sensory analyses revealed an aroma highly related to guava. These value-added food products are an alternative to process guava and avoid loss during postharvest handling.

  1. Direct methods for surface X-ray diffraction

    International Nuclear Information System (INIS)

    Saldin, D. K.; Harder, R.; Shneerson, V. L.; Vogler, H.; Moritz, W.

    2000-01-01

    We develop of a direct method for surface X-ray diffraction that exploits the holographic feature of a known reference wave from the substrate. A Bayesian analysis of the optimal inference to be made from an incomplete data set suggests a maximum entropy algorithm that balances agreement with the data and other statistical considerations

  2. Review of the Methods for Production of Spherical Ti and Ti Alloy Powder

    Science.gov (United States)

    Sun, Pei; Fang, Zhigang Zak; Zhang, Ying; Xia, Yang

    2017-10-01

    Spherical titanium alloy powder is an important raw material for near-net-shape fabrication via a powder metallurgy (PM) manufacturing route, as well as feedstock for powder injection molding, and additive manufacturing (AM). Nevertheless, the cost of Ti powder including spherical Ti alloy has been a major hurdle that prevented PM Ti from being adopted for a wide range of applications. Especially with the increasing importance of powder-bed based AM technologies, the demand for spherical Ti powder has brought renewed attention on properties and cost, as well as on powder-producing processes. The performance of Ti components manufactured from powder has a strong dependence on the quality of powder, and it is therefore crucial to understand the properties and production methods of powder. This article aims to provide a cursory review of the basic techniques of commercial and emerging methods for making spherical Ti powder. The advantages as well as limitations of different methods are discussed.

  3. Validation of missed space-group symmetry in X-ray powder diffraction structures with dispersion-corrected density functional theory.

    Science.gov (United States)

    Hempler, Daniela; Schmidt, Martin U; van de Streek, Jacco

    2017-08-01

    More than 600 molecular crystal structures with correct, incorrect and uncertain space-group symmetry were energy-minimized with dispersion-corrected density functional theory (DFT-D, PBE-D3). For the purpose of determining the correct space-group symmetry the required tolerance on the atomic coordinates of all non-H atoms is established to be 0.2 Å. For 98.5% of 200 molecular crystal structures published with missed symmetry, the correct space group is identified; there are no false positives. Very small, very symmetrical molecules can end up in artificially high space groups upon energy minimization, although this is easily detected through visual inspection. If the space group of a crystal structure determined from powder diffraction data is ambiguous, energy minimization with DFT-D provides a fast and reliable method to select the correct space group.

  4. Microstructural characterisation of battery materials using powder diffraction data: DIFFaX, FAULTS and SH-FullProf approaches

    Energy Technology Data Exchange (ETDEWEB)

    Casas-Cabanas, M.; Canales-Vazquez, J.; Palacin, M.R. [Institut de Ciencia de Materials de Barcelona (CSIC), Barcelona 08913 (Spain); Rodriguez-Carvajal, J. [Laboratoire Leon Brillouin (CEA-CNRS), Saclay, 91191 Gif-sur-Ivette Cedex (France); Laligant, Y.; Lacorre, P. [Laboratoire des Oxydes et Fluorures, UMR CNRS 6010, Universite du Maine, 72085 Le Mans Cedex (France)

    2007-12-06

    The microstructure of Li{sub 2}PtO{sub 3}, isostructural with Li{sub 2}MnO{sub 3}, and {beta}-Ni(OH){sub 2} is analyzed from powder diffraction data using two approaches. Firstly, the recently developed FAULTS program (a modification of the DIFFaX program to allow refinement of the diffraction pattern) is used to include different amounts and types of stacking faults in the microstructural description of the material. This approach treats size effects mostly isotropically and assigns most of the anisotropic peak broadening to stacking faults. On the other hand, the FullProf program is also used to perform Rietveld refinement with microstructural models that treat the effects of anisotropic size and hence considers that this is the main contribution to broadening. The simultaneous use of these two approaches allows choosing the most adequate model in each particular case in order to obtain an accurate description of the microstructure of the material. (author)

  5. Calculations of single crystal elastic constants for yttria partially stabilised zirconia from powder diffraction data

    Science.gov (United States)

    Lunt, A. J. G.; Xie, M. Y.; Baimpas, N.; Zhang, S. Y.; Kabra, S.; Kelleher, J.; Neo, T. K.; Korsunsky, A. M.

    2014-08-01

    Yttria Stabilised Zirconia (YSZ) is a tough, phase-transforming ceramic that finds use in a wide range of commercial applications from dental prostheses to thermal barrier coatings. Micromechanical modelling of phase transformation can deliver reliable predictions in terms of the influence of temperature and stress. However, models must rely on the accurate knowledge of single crystal elastic stiffness constants. Some techniques for elastic stiffness determination are well-established. The most popular of these involve exploiting frequency shifts and phase velocities of acoustic waves. However, the application of these techniques to YSZ can be problematic due to the micro-twinning observed in larger crystals. Here, we propose an alternative approach based on selective elastic strain sampling (e.g., by diffraction) of grain ensembles sharing certain orientation, and the prediction of the same quantities by polycrystalline modelling, for example, the Reuss or Voigt average. The inverse problem arises consisting of adjusting the single crystal stiffness matrix to match the polycrystal predictions to observations. In the present model-matching study, we sought to determine the single crystal stiffness matrix of tetragonal YSZ using the results of time-of-flight neutron diffraction obtained from an in situ compression experiment and Finite Element modelling of the deformation of polycrystalline tetragonal YSZ. The best match between the model predictions and observations was obtained for the optimized stiffness values of C11 = 451, C33 = 302, C44 = 39, C66 = 82, C12 = 240, and C13 = 50 (units: GPa). Considering the significant amount of scatter in the published literature data, our result appears reasonably consistent.

  6. Calculations of single crystal elastic constants for yttria partially stabilised zirconia from powder diffraction data

    Energy Technology Data Exchange (ETDEWEB)

    Lunt, A. J. G., E-mail: alexander.lunt@eng.ox.ac.uk; Xie, M. Y.; Baimpas, N.; Korsunsky, A. M. [Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ (United Kingdom); Zhang, S. Y.; Kabra, S.; Kelleher, J. [ISIS Neutron and Muon Source, Rutherford Appleton Laboratory, Harwell, Oxford OX11 0QX (United Kingdom); Neo, T. K. [Specialist Dental Group, Mount Elizabeth Orchard, 3 Mount Elizabeth, #08-03/08-08/08-10, Singapore 228510 (Singapore)

    2014-08-07

    Yttria Stabilised Zirconia (YSZ) is a tough, phase-transforming ceramic that finds use in a wide range of commercial applications from dental prostheses to thermal barrier coatings. Micromechanical modelling of phase transformation can deliver reliable predictions in terms of the influence of temperature and stress. However, models must rely on the accurate knowledge of single crystal elastic stiffness constants. Some techniques for elastic stiffness determination are well-established. The most popular of these involve exploiting frequency shifts and phase velocities of acoustic waves. However, the application of these techniques to YSZ can be problematic due to the micro-twinning observed in larger crystals. Here, we propose an alternative approach based on selective elastic strain sampling (e.g., by diffraction) of grain ensembles sharing certain orientation, and the prediction of the same quantities by polycrystalline modelling, for example, the Reuss or Voigt average. The inverse problem arises consisting of adjusting the single crystal stiffness matrix to match the polycrystal predictions to observations. In the present model-matching study, we sought to determine the single crystal stiffness matrix of tetragonal YSZ using the results of time-of-flight neutron diffraction obtained from an in situ compression experiment and Finite Element modelling of the deformation of polycrystalline tetragonal YSZ. The best match between the model predictions and observations was obtained for the optimized stiffness values of C11 = 451, C33 = 302, C44 = 39, C66 = 82, C12 = 240, and C13 = 50 (units: GPa). Considering the significant amount of scatter in the published literature data, our result appears reasonably consistent.

  7. Characterization of dense lead lanthanum titanate ceramics prepared from powders synthesized by the oxidant peroxo method

    Energy Technology Data Exchange (ETDEWEB)

    Pinto, Alexandre H. [LIEC-Laboratorio Interdisciplinar de Eletroquimica e Ceramica, Departamento de Quimica, UFSCar-Universidade Federal de Sao Carlos, Rod.Washington Luis km 235, CP 676 Sao Carlos, SP 13565-905 (Brazil); Souza, Flavio L., E-mail: flavio.souza@ufabc.edu.br [Centro de Ciencias Naturais e Humanas, Universidade Federal do ABC, Rua Santa Adelia 166, Bangu, Santo Andre, SP 09210-170 (Brazil); Chiquito, Adenilson J., E-mail: chiquito@df.ufscar.br [Departamento de Fisica, UFSCar-Federal University of Sao Carlos, Rod.Washington Luis km 235, CP 676 Sao Carlos, SP 13565-905 (Brazil); Longo, Elson, E-mail: elson@iq.unesp.br [Instituto de Quimica de Araraquara, UNESP-Universidade Estadual Paulista, Rua Francisco Degni, CP 355 Araraquara, SP 14801-907 (Brazil); Leite, Edson R., E-mail: derl@power.ufscar.br [LIEC-Laboratorio Interdisciplinar de Eletroquimica e Ceramica, Departamento de Quimica, UFSCar-Universidade Federal de Sao Carlos, Rod.Washington Luis km 235, CP 676 Sao Carlos, SP 13565-905 (Brazil); Camargo, Emerson R., E-mail: camargo@ufscar.br [LIEC-Laboratorio Interdisciplinar de Eletroquimica e Ceramica, Departamento de Quimica, UFSCar-Universidade Federal de Sao Carlos, Rod.Washington Luis km 235, CP 676 Sao Carlos, SP 13565-905 (Brazil)

    2010-12-01

    Nanosized powders of lead lanthanum titanate (Pb{sub 1-x}La{sub x}TiO{sub 3}) were synthesized by means of the oxidant-peroxo method (OPM). Lanthanum was added from 5 to 30% in mol through the dissolution of lanthanum oxide in nitric acid, followed by the addition of lead nitrate to prepare a solution of lead and lanthanum nitrates, which was dripped into an aqueous solution of titanium peroxo complexes, forming a reactive amorphous precipitate that could be crystallized by heat treatment. Crystallized powders were characterized by FT-Raman spectroscopy and X-ray powder diffraction, showing that tetragonal perovskite structure is obtained for samples up to 25% of lanthanum and cubic perovskite for samples with 30% of lanthanum. Powders containing 25 and 30% in mol of lanthanum were calcined at 700 deg. C for 2 h, and in order to determine the relative dielectric permittivity and the phase transition behaviour from ferroelectric-to-paraelectric, ceramic pellets were prepared and sintered at 1100 or 1150 deg. C for 2 h and subjected to electrical characterization. It was possible to observe that sample containing 25% in mol of La presented a normal behaviour for the phase transition, whereas the sample containing 30% in mol of La presented a diffuse phase transition and relaxor behaviour.

  8. Characterization of dense lead lanthanum titanate ceramics prepared from powders synthesized by the oxidant peroxo method

    International Nuclear Information System (INIS)

    Pinto, Alexandre H.; Souza, Flavio L.; Chiquito, Adenilson J.; Longo, Elson; Leite, Edson R.; Camargo, Emerson R.

    2010-01-01

    Nanosized powders of lead lanthanum titanate (Pb 1-x La x TiO 3 ) were synthesized by means of the oxidant-peroxo method (OPM). Lanthanum was added from 5 to 30% in mol through the dissolution of lanthanum oxide in nitric acid, followed by the addition of lead nitrate to prepare a solution of lead and lanthanum nitrates, which was dripped into an aqueous solution of titanium peroxo complexes, forming a reactive amorphous precipitate that could be crystallized by heat treatment. Crystallized powders were characterized by FT-Raman spectroscopy and X-ray powder diffraction, showing that tetragonal perovskite structure is obtained for samples up to 25% of lanthanum and cubic perovskite for samples with 30% of lanthanum. Powders containing 25 and 30% in mol of lanthanum were calcined at 700 deg. C for 2 h, and in order to determine the relative dielectric permittivity and the phase transition behaviour from ferroelectric-to-paraelectric, ceramic pellets were prepared and sintered at 1100 or 1150 deg. C for 2 h and subjected to electrical characterization. It was possible to observe that sample containing 25% in mol of La presented a normal behaviour for the phase transition, whereas the sample containing 30% in mol of La presented a diffuse phase transition and relaxor behaviour.

  9. Structural and morphological characterization of TiO2-ZrO2 powders obtained by the polymeric precursors method

    International Nuclear Information System (INIS)

    Ribeiro, M.A.; Gama, L.; Bispo, A.; Neiva, L.S.; Bernardi, M.I.B.; Kiminami, R.H.G.A.

    2010-01-01

    This work aims to characterize the structure and morphology of TiO 2 -ZrO 2 powders obtained by polymeric precursor method. For this we studied the following compositions: 0.25, 0.5 and 0.75 moles of Zr and calcined at 800 deg C for one hour. The powders obtained were characterized by XRD, SEM and nitrogen adsorption (BET). The analysis of X-ray diffraction showed that the powders had a phase of TiO 2 in the anatase form and a tetragonal phase of ZrO 2 . The crystallite size was between 8, 13 and 11 nm respectively. The analysis of scanning electron microscopy showed the growth of ZrO 2 nanoparticles and that these comprise spherical agglomerates of less than 100 nm. Particle size determined by the BET ranging 28.1-29.5 nm, showing thereby the character of nanosized powders. (author)

  10. Report on neutron powder diffraction for the Australian Replacement Research Reactor

    International Nuclear Information System (INIS)

    Hunter, B.A.

    2000-01-01

    There is a clear need for two neutron powder diffractometers at the Australian Replacement Research Reactor when it starts operation in 2005. The high-intensity instrument should be capable of measuring a 10mg sample of moderate complexity, or perform single-shot time-resolved experiments with 1-second time slices, or perform stroboscopic measurements with time slices of order 50 microseconds. The high-resolution instrument should have a target resolution of Δd/d∼6x10 -4 , and be capable of collecting data at this resolution within 1-48 hours depending on sample size and crystal complexity. Key questions that need to be answered in the next 9 months include: (1) a detailed study of monochromator options, (2) analysing the detector options for the high-intensity machine and exploring ways in which the solid angle can be maximised for both instruments, (3) whether the instruments are better situated at the reactor face or on super mirror guides, (4) how to integrate the two instruments (physically, if they are only the same guide), and scientifically as regards detailed performance specifications. The user community clearly wants a wide range of sample-environment options, and these are listed in the report. Combinations of these options will be important

  11. Evaluation of laboratory powder X-ray micro-diffraction for applications in the fields of cultural heritage and forensic science.

    Science.gov (United States)

    Svarcová, Silvie; Kocí, Eva; Bezdicka, Petr; Hradil, David; Hradilová, Janka

    2010-09-01

    The uniqueness and limited amounts of forensic samples and samples from objects of cultural heritage together with the complexity of their composition requires the application of a wide range of micro-analytical methods, which are non-destructive to the samples, because these must be preserved for potential late revision. Laboratory powder X-ray micro-diffraction (micro-XRD) is a very effective non-destructive technique for direct phase analysis of samples smaller than 1 mm containing crystal constituents. It compliments optical and electron microscopy with elemental micro-analysis, especially in cases of complicated mixtures containing phases with similar chemical composition. However, modification of X-ray diffraction to the micro-scale together with its application for very heterogeneous real samples leads to deviations from the standard procedure. Knowledge of both the limits and the phenomena which can arise during the analysis is crucial for the meaningful and proper application of the method. We evaluated basic limits of micro-XRD equipped with a mono-capillary with an exit diameter of 0.1 mm, for example the size of irradiated area, appropriate grain size, and detection limits allowing identification of given phases. We tested the reliability and accuracy of quantitative phase analysis based on micro-XRD data in comparison with conventional XRD (reflection and transmission), carrying out experiments with two-phase model mixtures simulating historic colour layers. Furthermore, we demonstrate the wide use of micro-XRD for investigation of various types of micro-samples (contact traces, powder traps, colour layers) and we show how to enhance data quality by proper choice of experiment geometry and conditions.

  12. Structure and thermal expansion of Ca9Gd(VO4)7: A combined powder-diffraction and dilatometric study of a Czochralski-grown crystal

    Science.gov (United States)

    Paszkowicz, Wojciech; Shekhovtsov, Alexei; Kosmyna, Miron; Loiko, Pavel; Vilejshikova, Elena; Minikayev, Roman; Romanowski, Przemysław; Wierzchowski, Wojciech; Wieteska, Krzysztof; Paulmann, Carsten; Bryleva, Ekaterina; Belikov, Konstantin; Fitch, Andrew

    2017-11-01

    Materials of the Ca9RE(VO4)7 (CRVO) formula (RE = rare earth) and whitlockite-related structures are considered for applications in optoelectronics, e.g., in white-light emitting diodes and lasers. In the CRVO structure, the RE atoms are known to share the site occupation with Ca atoms at two or three among four Ca sites, with partial occupancy values depending on the choice of the RE atom. In this work, the structure and quality of a Czochralski-grown crystal of this family, Ca9Gd(VO4)7 (CGVO), are studied using X-ray diffraction methods. The room-temperature structure is refined using the powder diffraction data collected at a high-resolution synchrotron beamline ID22 (ESRF, Grenoble); for comparison purposes, a laboratory diffraction pattern was collected and analyzed, as well. The site occupancies are discussed on the basis of comparison with literature data of isostructural synthetic crystals of the CRVO series. The results confirm the previously reported site-occupation scheme and indicate a tendency of the CGVO compound to adopt a Gd-deficient composition. Moreover, the thermal expansion coefficient is determined for CGVO as a function of temperature in the 302-1023 K range using laboratory diffraction data. Additionally, for CGVO and six other single crystals of the same family, thermal expansion is studied in the 298-473 K range, using the dilatometric data. The magnitude and anisotropy of thermal expansion, being of importance for laser applications, are discussed for these materials.

  13. Crystal Engineering on Industrial Diaryl Pigments Using Lattice Energy Minimizations and X-ray Powder Diffraction

    International Nuclear Information System (INIS)

    Schmidt, M.; Dinnebier, R.; Kalkhof, H.

    2007-01-01

    Diaryl azo pigments play an important role as yellow pigments for printing inks, with an annual pigment production of more than 50,000 t. The crystal structures of Pigment Yellow 12 (PY12), Pigment Yellow 13 (PY13), Pigment Yellow 14 (PY14), and Pigment Yellow 83 (PY83) were determined from X-ray powder data using lattice energy minimizations and subsequent Rietveld refinements. Details of the lattice energy minimization procedure and of the development of a torsion potential for the biphenyl fragment are given. The Rietveld refinements were carried out using rigid bodies, or constraints. It was also possible to refine all atomic positions individually without any constraint or restraint, even for PY12 having 44 independent non-hydrogen atoms per asymmetric unit. For PY14 (23 independent non-hydrogen atoms), additionally all atomic isotropic temperature factors could be refined individually. PY12 crystallized in a herringbone arrangement with twisted biaryl fragments. PY13 and PY14 formed a layer structure of planar molecules. PY83 showed a herringbone structure with planar molecules. According to quantum mechanical calculations, the twisting of the biaryl fragment results in a lower color strength of the pigments, whereas changes in the substitution pattern have almost no influence on the color strength of a single molecule. Hence, the experimentally observed lower color strength of PY12 in comparison with that of PY13 and PY83 can be explained as a pure packing effect. Further lattice energy calculations explained that the four investigated pigments crystallize in three different structures because these structures are the energetically most favorable ones for each compound. For example, for PY13, PY14, or PY83, a PY12-analogous crystal structure would lead to considerably poorer lattice energies and lower densities. In contrast, lattice energy calculations revealed that PY12 could adopt a PY13-type structure with only slightly poorer energy. This structure was

  14. Evaluation of laboratory powder X-ray micro-diffraction for applications in the fields of cultural heritage and forensic science

    Czech Academy of Sciences Publication Activity Database

    Švarcová, Silvie; Kočí, Eva; Bezdička, Petr; Hradil, David; Hradilová, J.

    2010-01-01

    Roč. 398, č. 2 (2010), s. 1061-1076 ISSN 1618-2642 R&D Projects: GA AV ČR KJB200320901 Institutional research plan: CEZ:AV0Z40320502 Keywords : powder X-ray micro-diffraction * quantitative phase analysis * forensic Subject RIV: CA - Inorganic Chemistry Impact factor: 3.841, year: 2010

  15. The structural phase diagram and oxygen equilibrium partial pressure of YBa2CU3O6+x studied by neutron powder diffraction and gas volumetry

    DEFF Research Database (Denmark)

    Andersen, N.H.; Lebech, B.; Poulsen, H.F.

    1990-01-01

    An experimental technique based on neutron powder diffraction and gas volumetry is presented and used to study the structural phase diagram of YBa2Cu3O6+x under equilibrium conditions in an extended part of (x, T)-phase (0.15

  16. Study of crystallite size of yttria-stabilized zirconia powders by Rietveld method

    International Nuclear Information System (INIS)

    Leite, Wellington Claiton; Brinatti, Andre Mauricio; Ribeiro, Mauricio Aparecido; Andrade, Andre Vitor Chaves de; Chinelatto, Adriana Scoton Antonio; Chinelatto, Adilson Luiz

    2009-01-01

    The yttria-stabilized zirconia (YSZ) is used in a great variety of applications, for example, electrolytes of solid oxide fuel cells and oxygen sensors. In the study of YSZ, the particle size powders and sintering processes are important to define the final properties of the zirconia products. The objectives of this work were to determine the phases and the crystalline size using X-Ray Diffraction (XRD) data and the Rietveld Method (RM) of the YSZ powders obtained by chemical synthesis based on the Pechini method. It was used ZrOCl 2.8 H 2 O and Y(NO 3 ) 3.5 H 2 O as precursors reagents. After calcination at 550 deg C during 24 hours, the powder was analyzed by XRD and scanning electronic microscopy (SEM). From XRD and using Rietveld method were verified that there is only cubic phase with lattice parameter a = 5.1307(1) Å and the space group Fm3m. Due to substitution of the Zr atoms in the Y atoms sites, there were vacancies in 17.72 % of O atoms sites. However, the percentage of substitution of Zr atoms in Y atoms sites in the structure not was determinate because the curves of atomic scattering of them are very similar. Using Scherrer equation and considering anisotropy effect, the average crystalline size was determinate: 10,43 nm (c axis) and 10,39 (b axis). This spherical symmetry also observed for SEM. (author)

  17. Absolute determination by X-ray diffraction of a binary or ternary mixture: nickel oxide and fluoride in a nickel powder (1960); Dosage absolu par diffraction X d'un melange binaire ou ternaire: oxyde et fluorure de nickel dans une poudre de nickel (1960)

    Energy Technology Data Exchange (ETDEWEB)

    Charpin, P; Hauptman, A [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1960-07-01

    The method employed is based upon the comparison between computed and measured intensities for conveniently selected X-Ray diffraction lines of each component of the powder. Care must be taken to allow for absorption, both inside each grain and in overall sample. This method has been applied to the determination of nickel oxide and fluoride in a nickel powder. (author) [French] La methode utilisee, dite 'absolue' est basee sur le calcul des intensites theoriques de raies de diffraction convenablement choisies. Elle n'est applicable que si l'absorption est negligeable a travers chaque grain constituant l'echantillon et a travers l'echantillon total. Elle a ete employee pour doser, ensemble ou separement, de l'oxyde et du fluorure de nickel dans une poudre de nickel. (auteur)

  18. Validation of the method of quantitative phase analysis by X-ray diffraction in API: case of Tibolone

    International Nuclear Information System (INIS)

    Silva, R P; Ambrósio, M F S; Epprecht, E K; Avillez, R R; Achete, C A; Kuznetsov, A; Visentin, L C

    2016-01-01

    In this study, different structural and microstructural models applied to X-ray analysis of powder diffraction data of polymorphic mixtures of known concentrations of Tibolone were investigated. The X-ray data obtained in different diffraction instruments were analysed via Rietveld method using the same analytical models. The results of quantitative phase analysis show that regardless of the instrument used, the values of the calculated concentrations follow the same systematics with respect to the final errors. The strategy to select a specific analytical model that leads to lower measurement errors is here presented. (paper)

  19. Morphological characterization of tungsten trioxide nano powders synthesized by Sol-Gel modified Pechini's method

    Energy Technology Data Exchange (ETDEWEB)

    Ghasemi, Leila; Jafari, Hassan, E-mail: jafari_h@yahoo.com [Department of Materials Engineering, Faculty of Mechanical Engineering, Shahid Rajaee Teacher Training University, Tehran (Iran, Islamic Republic of)

    2017-11-15

    Sol-gel modified Pechini's method was used to prepare WO{sub 3} nano powders using dicarboxylic acid and polyethylene glycol as the chelating agent and polymeric source, respectively. WO{sub 3} powders were first prepared by calcination of resin precursor at 550 deg C under various initial concentrations of metal ion (12.5-50 mmol), acid (125-500 mmol), a complexing agent (32-262 mmol), and polyethylene glycol (1-16.5 mmol) in the air atmosphere. The products were characterized using X-ray powder diffraction, field emission scanning electron microscopy, and energy dispersive spectroscopy. The results revealed that the WO{sub 3} nano powders prepared with different amounts of chelating agent and polyethylene glycol, crystallized in monoclinic phase. The nano powders were impurity-free due to the presence of the complexing agent and polyethylene glycol as carbon sources. Morphological evolution indicated that the nano powders evolved from rod-like to regular and spherical shapes, depending on complexing agent and polyethylene glycol amounts. Nano powders with an average particle size of approximately 58 nm and a narrow size distribution were obtained. (author)

  20. Morphological characterization of tungsten trioxide nano powders synthesized by Sol-Gel modified Pechini's method

    International Nuclear Information System (INIS)

    Ghasemi, Leila; Jafari, Hassan

    2017-01-01

    Sol-gel modified Pechini's method was used to prepare WO 3 nano powders using dicarboxylic acid and polyethylene glycol as the chelating agent and polymeric source, respectively. WO 3 powders were first prepared by calcination of resin precursor at 550 deg C under various initial concentrations of metal ion (12.5-50 mmol), acid (125-500 mmol), a complexing agent (32-262 mmol), and polyethylene glycol (1-16.5 mmol) in the air atmosphere. The products were characterized using X-ray powder diffraction, field emission scanning electron microscopy, and energy dispersive spectroscopy. The results revealed that the WO 3 nano powders prepared with different amounts of chelating agent and polyethylene glycol, crystallized in monoclinic phase. The nano powders were impurity-free due to the presence of the complexing agent and polyethylene glycol as carbon sources. Morphological evolution indicated that the nano powders evolved from rod-like to regular and spherical shapes, depending on complexing agent and polyethylene glycol amounts. Nano powders with an average particle size of approximately 58 nm and a narrow size distribution were obtained. (author)

  1. In situ X-ray powder diffraction studies of the synthesis of graphene oxide and formation of reduced graphene oxide

    International Nuclear Information System (INIS)

    Storm, Mie Møller; Johnsen, Rune E.; Norby, Poul

    2016-01-01

    Graphene oxide (GO) and reduced graphene oxide (rGO) are important materials in a wide range of fields. The modified Hummers methods, for synthesizing GO, and subsequent thermal reduction to rGO, are often employed for production of rGO. However, the mechanism behinds these syntheses methods are still unclear. We present an in situ X-ray diffraction study of the synthesis of GO and thermal reduction of GO. The X-ray diffraction revealed that the Hummers method includes an intercalation state and finally formation of additional crystalline material. The formation of GO is observed during both the intercalation and the crystallization stage. During thermal reduction of GO three stages were observed: GO, a disordered stage, and the rGO stage. The appearance of these stages depends on the heating ramp. The aim of this study is to provide deeper insight into the chemical and physical processes during the syntheses. - Graphical abstract: In situ X-ray diffraction results for of the modified Hummers synthesis and the thermal reduction of graphene oxide, revealing three stages for both syntheses as well as new GO diffraction peaks and unidentified crystalline material for the Hummers synthesis and a disordered stage for the thermal reduction of graphene oxide. Display Omitted - Highlights: • Hummers synthesis consists of three stages: dissolution, intercalation and crystal. • GO is produced early on during the synthesis and display new diffraction peaks. • An unidentified triclinic phase is observed for the Hummers synthesis. • Thermal reduction of GO display three stages: GO, a disordered stage and rGO. • In situ XRD indicate reformation of rGO even for fast heated thermal reduction.

  2. In situ X-ray powder diffraction studies of the synthesis of graphene oxide and formation of reduced graphene oxide

    Energy Technology Data Exchange (ETDEWEB)

    Storm, Mie Møller, E-mail: mmst@dtu.dk; Johnsen, Rune E.; Norby, Poul

    2016-08-15

    Graphene oxide (GO) and reduced graphene oxide (rGO) are important materials in a wide range of fields. The modified Hummers methods, for synthesizing GO, and subsequent thermal reduction to rGO, are often employed for production of rGO. However, the mechanism behinds these syntheses methods are still unclear. We present an in situ X-ray diffraction study of the synthesis of GO and thermal reduction of GO. The X-ray diffraction revealed that the Hummers method includes an intercalation state and finally formation of additional crystalline material. The formation of GO is observed during both the intercalation and the crystallization stage. During thermal reduction of GO three stages were observed: GO, a disordered stage, and the rGO stage. The appearance of these stages depends on the heating ramp. The aim of this study is to provide deeper insight into the chemical and physical processes during the syntheses. - Graphical abstract: In situ X-ray diffraction results for of the modified Hummers synthesis and the thermal reduction of graphene oxide, revealing three stages for both syntheses as well as new GO diffraction peaks and unidentified crystalline material for the Hummers synthesis and a disordered stage for the thermal reduction of graphene oxide. Display Omitted - Highlights: • Hummers synthesis consists of three stages: dissolution, intercalation and crystal. • GO is produced early on during the synthesis and display new diffraction peaks. • An unidentified triclinic phase is observed for the Hummers synthesis. • Thermal reduction of GO display three stages: GO, a disordered stage and rGO. • In situ XRD indicate reformation of rGO even for fast heated thermal reduction.

  3. Green synthesis of nanocrystalline α-Al2O3 powders by both wet-chemical and mechanochemical methods

    Science.gov (United States)

    Gao, Huiying; Li, Zhiyong; Zhao, Peng

    2018-03-01

    Nanosized α-Al2O3 powders were prepared with AlCl3ṡ6H2O and NH4HCO3 as raw materials by both wet-chemical and mechanochemical methods, through the synthesis of the ammonium aluminum carbonate hydroxide (AACH) precursor followed by calcination. The environmentally benign starch was used as an effective dispersant during the preparation of nanocrystalline α-Al2O3 powders. X-ray diffraction (XRD), thermogravimetric differential thermal analysis (TG-DTA), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were employed to characterize the precursor AACH and products. The results show that nanosized spherical α-Al2O3 powders without hard agglomeration and with particle size in the range of 20-40 nm can be obtained by the two methods. Comparing the two “green” processes, the mechanochemical method has better prospects for commercial production.

  4. Neutron diffraction technique as a method for material studies

    International Nuclear Information System (INIS)

    Belhorma, B.; Labrim, H.; Gandou, Z.

    2010-01-01

    The Morocco's first Nuclear Research has been constructed in CNESTEN. The reactor divergence has been tested, and the nominal power of 2MW was successfully achieved. The reactor has 4 beam ports two of them are projected for neutron scattering. Such technique allows studying the crystallographic and magnetic structures of materials using the thermal neutrons produced in the reactor. the powder diffractometer has been designed. Component reception and installation procedures are in progress. The second experiment consists on small angle neutron scattering that allows the study of soft matter and polymers in the range of 1-50 nm. The third technique that can complete the two previous is the 4-circle neutron spectrometry which is designed mainly to study structural properties of the mono-crystalline material and texture.This technique is complementary to the X-ray diffraction already available in CNESTEN. Some applications of this technique are: --to determine the crystallographic and magnetic structure of polycrystalline materials.-- to study the texture in metals and alloys.-- to perform holography measurement

  5. In vitro bioactivity of a biocomposite fabricated from HA and Ti powders by powder metallurgy method.

    Science.gov (United States)

    Ning, C Q; Zhou, Y

    2002-07-01

    Traditionally, hydroxyapatite was used as a coating material on titanium substrate by various techniques. In the present work, a biocomposite was successfully fabricated from hydroxyapatite and titanium powders by powder metallurgy method. Bioactivity of the composite in a simulated body fluid (SBF) was investigated. Main crystal phases of the as-fabricated composite are found to be Ti2O, CaTiO3, CaO, alpha-Ti and a TiP-like phase. When the composite is immersed in the simulated body fluid for a certain time, a poor-crystallized, calcium-deficient, carbonate-containing apatite film will form on the surface of the composite. The time required to induce apatite nucleation is within 2 h. In addition, the apatite is also incorporated with a little magnesium and chlorine element. It is found that Ti2O has the ability to induce the formation of bone-like apatite in the SBF. And a dissolve of the CaO phase could also provide favorable conditions for the apatite formation, by forming open pores on the surface of the composite and increasing the degree of supersaturation of the SBF with respect to the apatite.

  6. Tailoring diffraction technique Rietveld method on residual stress measurements of cold-can oiled 304 stainless steel plates

    International Nuclear Information System (INIS)

    Parikin; Killen, P.; Anis, M.

    2003-01-01

    Tailoring of diffraction technique-Rietveld method on residual stress measurements of cold-canailed stainless steel 304 plates assuming the material is isotopic, the residual stress measurements using X-ray powder diffraction is just performed for a plane lying in a large angle. For anisotropic materials, the real measurements will not be represented by the methods. By Utilizing of all diffraction peaks in the observation region, tailoring diffraction technique-Rietveld analysis is able to cover the limitations. The residual stress measurement using X-ray powder diffraction tailored by Rietveld method, in a series of cold-canailed stainless steel 304 plates deforming; 0, 34, 84, 152, 158, 175, and 196 % reduction in thickness, have been reported. The diffraction data were analyzed by using Rietveld structure refinement method. Also, for all cold-canailed stainless steel 304 plates cuplikans, the diffraction peaks are broader than the uncanailed one, indicating that the strains in these cuplikans are inhomogeneous. From an analysis of the refined peak shape parameters, the average root-mean square strain, which describes the distribution of the inhomogeneous strain field, was calculated. Finally, the average residual stresses in cold-canailed stainless steel 304 plates were shown to be a combination effect of hydrostatic stresses of martensite particles and austenite matrix. The average residual stresses were evaluated from the experimentally determined average lattice strains in each phase. It was found the tensile residual stress in a cuplikan was maximum, reaching 442 MPa, for a cuplikan reducing 34% in thickness and minimum for a 196% cuplikan

  7. [Determination method of polysorbates in powdered soup by HPLC].

    Science.gov (United States)

    Takeda, Y; Abe, Y; Ishiwata, H; Yamada, T

    2001-04-01

    A method for qualitative and quantitative analyses of polysorbates in powdered soup by HPLC was studied. Polysorbates in samples were extracted with acetonitrile after rinsing with n-hexane to remove fats and oils. The extract was cleaned up using a Bond Elut silica gel cartridge (500 mg). The cartridge was washed with ethyl acetate and polysorbates were eluted with a small amount of acetonitrile-methanol (1:2) mixture. The eluate was treated with cobalt thiocyanate solution to form a blue complex with polysorbate. In order to determine polysorbate, the complex was subjected to HPLC with a GPC column, using a mixture of acetonitrile-water (95:5) as a mobile phase, with a detection wavelength of 620 nm. The recoveries of polysorbate 80 added to powdered soups were more than 75% and the determination limit was 0.04 mg/g. When the proposed method was applied to the determination of polysorbates in 16 commercial samples of powdered soup for instant noodles and seasoning consomme, no polysorbates were detected in any sample.

  8. A drop penetration method to measure powder blend wettability.

    Science.gov (United States)

    Wang, Yifan; Liu, Zhanjie; Muzzio, Fernando; Drazer, German; Callegari, Gerardo

    2018-03-01

    Water wettability of pharmaceutical blends affects important quality attributes of final products. We investigate the wetting properties of a pharmaceutical blend lubricated with Magnesium Stearate (MgSt) as a function of the mechanical shear strain applied to the blend. We measure the penetration dynamics of sessile drops deposited on slightly compressed powder beds. We consider a blend composed of 9% Acetaminophen 90% Lactose and 1% MgSt by weight. Comparing the penetration time of water and a reference liquid Polydimethylsiloxane (silicon oil) we obtain an effective cosine of the contact angle with water, based on a recently developed drop penetration method. We repeat the experiments for blends exposed to increasing levels of shear strain and demonstrate a significant decrease in water wettability (decrease in the cosine of the contact angle). The results are consistent with the development of a hydrophobic film coating the powder particles as a result of the increased shear strain. Finally, we show that, as expected dissolution times increase with the level of shear strain. Therefore, the proposed drop penetration method could be used to directly assess the state of lubrication of a pharmaceutical blend and act as a quality control on powder blend attributes before the blend is tableted. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Phase and Chemical Composition Analysis on Neolithic Painted Ceramics Sherds Using Synchrotron Radiation X-Ray Powder Diffraction (SRXPD)

    International Nuclear Information System (INIS)

    Constantinescu, B.

    2003-01-01

    Full text: Synchrotron Radiation X-ray Powder Diffraction studies were performed at the wiggler beamline 1711 of MAX II Synchrotron accelerator from Lund, Sweden, in the frame of EU FPV Access to Large Scale Facilities programme. Diffraction data were collected using radiation of wavelength 1.36 A, which was detected by a Brucker system with a Smart 1000 CCD detector. The main goal of our studies was to distinguish different clays and mineral pigments of various Neolithic pottery-producing centres on Romanian territory in relation with possible inter-regional trade route connections. As main results we can mention: - identification of black pigment composition from Cucuteni (Northern Moldavia), Ariusd (South-Eastern Transylvania) and Cris-Starcevo (Oltenia) type pottery (VI - IV Millennia B. Chr.) as a combination of jacobsite, bixbyite (Manganese oxides), magnetite and goethite (Iron oxides) originary from North Moldova mineral deposits of Iacobeni (150 km up on the river Bistritza from analyzed Cucuteni archaeological sites), and as a combination of pyrolusite, magnetite and hematite for Cris-Starcevo samples, probably from local clay (enriched in Mn-Fe oxides) - identification of white pigment composition as calcite (CaCO3) for Cris- Starcevo culture sites from Central Transylvania (from the local abundant chalk deposits) and as calcium silicates mixed with illite (K, H2))Al2[(H2O, OH)2]AlSi3O10 for Cucuteni culture sites - identification of read-brown pigment composition as various mixtures of hematite - goethite - magnetite, all of local provenance - identification of all examined sherds as having local provenance for the clay The main conclusion is that during Neolithic period, the pottery workshops, largely extended on Romanian territory, used local clays but traded black mineral pigments across the Carpathian mountains (Cucuteni and Ariusd areas are separated by these mountains by easily crossed by passes along small rivers)

  10. Direct method of deconvolution. Application to the interpretation of X ray diffraction line profiles

    International Nuclear Information System (INIS)

    Louer, Daniel

    1969-01-01

    In the first parts of this research thesis, the author reports the development of an original method of correction of X ray profiles, and the comparison of the different correction schemes within the frame of the analysis of a specific aberration of the diffractometer: the receiver slot. Based on corrected profiles, the author applied the different methods leading to the calculation of the dimensions and shape of particles which form a hydroxide nickel powder. He reports the physical-chemical analysis of nickel and zinc basic nitrates. Although some basic salts lead to widened X diffraction profiles the interpretation of which remains to be made, this work remained limited to the application of the described methods to the nickel hydroxide sample resulting from an extended hydrolysis of nickel basic nitrates

  11. Evaluation of Rock Powdering Methods to Obtain Fine-grained Samples for CHEMIN, a Combined XRD/XRF Instrument

    Science.gov (United States)

    Chipera, S. J.; Vaniman, D. T.; Bish, D. L.; Sarrazin, P.; Feldman, S.; Blake, D. F.; Bearman, G.; Bar-Cohen, Y.

    2004-01-01

    A miniature XRD/XRF (X-ray diffraction / X-ray fluorescence) instrument, CHEMIN, is currently being developed for definitive mineralogic analysis of soils and rocks on Mars. One of the technical issues that must be addressed to enable remote XRD analysis is how best to obtain a representative sample powder for analysis. For powder XRD analyses, it is beneficial to have a fine-grained sample to reduce preferred orientation effects and to provide a statistically significant number of crystallites to the X-ray beam. Although a two-dimensional detector as used in the CHEMIN instrument will produce good results even with poorly prepared powder, the quality of the data will improve and the time required for data collection will be reduced if the sample is fine-grained and randomly oriented. A variety of methods have been proposed for XRD sample preparation. Chipera et al. presented grain size distributions and XRD results from powders generated with an Ultrasonic/Sonic Driller/Corer (USDC) currently being developed at JPL. The USDC was shown to be an effective instrument for sampling rock to produce powder suitable for XRD. In this paper, we compare powder prepared using the USDC with powder obtained with a miniaturized rock crusher developed at JPL and with powder obtained with a rotary tungsten carbide bit to powders obtained from a laboratory bench-scale Retsch mill (provides benchmark mineralogical data). These comparisons will allow assessment of the suitability of these methods for analysis by an XRD/XRF instrument such as CHEMIN.

  12. Complementing high-throughput X-ray powder diffraction data with quantum-chemical calculations

    DEFF Research Database (Denmark)

    Naelapaa, Kaisa; van de Streek, Jacco; Rantanen, Jukka

    2012-01-01

    of piroxicam form III. These combined experimental/quantum-chemical methods can provide access to reliable structural information in the course of an intensive experimentally based solid-form screening activity or in other circumstances wherein single crystals might never be viable, for example, for polymorphs...

  13. Analysis of an industrial production suspension of Bacillus lentus subtilisin crystals by powder diffraction: a powerful quality-control tool.

    Science.gov (United States)

    Frankaer, Christian G; Moroz, Olga V; Turkenburg, Johan P; Aspmo, Stein I; Thymark, Majbritt; Friis, Esben P; Stahl, Kenny; Nielsen, Jens E; Wilson, Keith S; Harris, Pernille

    2014-04-01

    A microcrystalline suspension of Bacillus lentus subtilisin (Savinase) produced during industrial large-scale production was analysed by X-ray powder diffraction (XRPD) and X-ray single-crystal diffraction (MX). XRPD established that the bulk microcrystal sample representative of the entire production suspension corresponded to space group P212121, with unit-cell parameters a = 47.65, b = 62.43, c = 75.74 Å, equivalent to those for a known orthorhombic crystal form (PDB entry 1ndq). MX using synchrotron beamlines at the Diamond Light Source with beam dimensions of 20 × 20 µm was subsequently used to study the largest crystals present in the suspension, with diffraction data being collected from two single crystals (∼20 × 20 × 60 µm) to resolutions of 1.40 and 1.57 Å, respectively. Both structures also belonged to space group P2(1)2(1)2(1), but were quite distinct from the dominant form identified by XRPD, with unit-cell parameters a = 53.04, b = 57.55, c = 71.37 Å and a = 52.72, b = 57.13, c = 65.86 Å, respectively, and refined to R = 10.8% and Rfree = 15.5% and to R = 14.1% and Rfree = 18.0%, respectively. They are also different from any of the forms previously reported in the PDB. A controlled crystallization experiment with a highly purified Savinase sample allowed the growth of single crystals of the form identified by XRPD; their structure was solved and refined to a resolution of 1.17 Å with an R of 9.2% and an Rfree of 11.8%. Thus, there are at least three polymorphs present in the production suspension, albeit with the 1ndq-like microcrystals predominating. It is shown how the two techniques can provide invaluable and complementary information for such a production suspension and it is proposed that XRPD provides an excellent quality-control tool for such suspensions.

  14. Geometrically frustrated magnetic structures of the heavy-fermion compound CePdAl studied by powder neutron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Doenni, A.; Fischer, P.; Zolliker, M. [Laboratory for Neutron Scattering, ETH Zuerich and Paul Scherrer Institute, CH-5232 Villigen PSI (Switzerland); Ehlers, G.; Maletta, H. [Hahn Meitner Institute Berlin, Glienicker Strasse 100, D-14092 Berlin (Germany); Kitazawa, H. [National Research Institute for Metals, Tsukuba, Ibaraki 305 (Japan)

    1996-12-09

    The heavy-fermion compound CePdAl with ZrNiAl-type crystal structure (hexagonal space group P6-bar2m) was investigated by powder neutron diffraction. The triangular coordination symmetry of magnetic Ce atoms on site 3f gives rise to geometrical frustration. CePdAl orders below T{sub N} = 2.7 K with an incommensurate antiferromagnetic propagation vector k=[1/2, 0, {tau}], {tau} approx. 0.35, and a longitudinal sine-wave (LSW) modulated spin arrangement. Magnetically ordered moments at Ce(1) and Ce(3) coexist with frustrated disordered moments at Ce(2). The experimentally determined magnetic structure is in agreement with group theoretical symmetry analysis considerations, calculated by the program MODY, which confirm that for Ce(2) an ordered magnetic moment parallel to the magnetically easy c-axis is forbidden by symmetry. Further low-temperature experiments give evidence for a second magnetic phase transition in CePdAl between 0.6 and 1.3 K. Magnetic structures of CePdAl are compared with those of the isostructural compound TbNiAl, where a non-zero ordered magnetic moment for the geometrically frustrated Tb(2) atoms is allowed by symmetry. (author)

  15. Rietveld profile analysis of calcined AlPO/sub 4/-11 using pulsed neutron powder diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Richardson, J.W. Jr.; Pluth, J.J.; Smith, J.V.

    1988-08-01

    Aluminium phosphate, AlPO/sub 4/, M/sub r/=121.95, orthorhombic, Icmm (disordered Al, P), Icm2 (ordered Al, P), a=13.5333(8), b=18.4845(10), c=8.3703(4) A, V=2094 A/sup 3/, Z=20, D/sub x/=1.93 g cm/sup -3/, T approx. = 295 K, R/sub wp/=0.031, R/sub F//sup 2/=0.109 (Icmm) and R/sub wp/=0.027, R/sub F//sup 2/=0.058 (Icm2) for 1017 independent reflections. Sample calcined at 873 K and dehydrated at 573 K. Time-of-flight neutron powder diffraction data were taken on the GPPD diffractometer at the Argonne National Laboratory Intense Pulsed Neutron Source. The structure was refined by Rietveld profile analysis in the range d=0.86-3.91 A in two space groups: Icmm assuming no ordering of Al and P, and Icm2 assuming strict alternation of Al and P on tetrahedral nodes. (orig./BHo).

  16. A study of nitrogenation of a NdFe12-xMox compound by in situ neutron powder diffraction

    International Nuclear Information System (INIS)

    Loong, C.; Short, S.M.; Lin, J.; Ding, Y.

    1998-01-01

    The effects on the crystal lattice of a NdFe 12-x Mo x (x congruent 1.7) during controlled nitrogenation over the 25 endash 600 degree C temperature range were studied by neutron powder diffraction. Prior to nitrogenation the sample contained a major phase of NdFe 10.3 Mo 1.7 and a minor phase (∼12vol%) of bcc-Fe. The sample inside the furnace was connected to a closed volume of ultrapure nitrogen gas while neutron data were collected over regular time intervals during sequential heating. Substantial nitrogen absorption occurred between 500 and 600 degree C. During the nitrogenation process the NdFe 12-x Mo x N y lattice expanded while the bcc-Fe lattice contracted. An increasing decomposition of the compound into bcc-Fe at 600 degree C was observed. The average size of the NdFe 12-x Mo x N y crystalline grains decreased starting at ∼300 degree C, reaching a minimum at ∼500 degree C and then increased markedly at higher temperatures. The development of lattice strains, on the other hand, showed an opposite trend, i.e., a maximum at 500 degree C. copyright 1998 American Institute of Physics

  17. Effect of powder sample granularity on fluorescent intensity and on thermal parameters in x-ray diffraction Rietveld analysis

    International Nuclear Information System (INIS)

    Sparks, C.J.; Specht, E.D.; Ice, G.E.; Kumar, R.; Zschack, P.; Shiraishi, T.; Hisatsune, K.

    1991-01-01

    The effect of sample granularity on diffracted x-ray intensity was evaluated by measuring the 2θ dependence of x-ray fluorescence from various samples. Measurements were made in the symmetric geometry on samples ranging from single crystals to highly absorbing coarse powders. A characteristic shape for the absorption correction was observed. A demonstration of the sensitivity of Rietveld refined site occupation parameters is made on CuAu and Cu 50 Au 44 Ni 6 alloys refined with and without granularity corrections. These alloys provide a good example of the effect of granularity due to their large linear x-ray absorption coefficients. Sample granularity and refined thermal parameters obtained from the Rietveld analysis were found to be correlated. Without a granularity correction, the refined thermal parameters are too low and can actually become negative in an attempt to compensate for granularity. A general shape for granularity correction can be included in refinement procedures. If no granularity correction is included, data should be restricted to above 30 degrees 2θ, and thermal parameters should be ignored unless extreme precautions are taken to produce >5 μm particles and high packing densities

  18. Ab initio determination of the novel perovskite-related structure of La7Mo7O30 from powder diffraction

    International Nuclear Information System (INIS)

    Goutenoire, F.; Retoux, R.; Lacorre, P.

    1999-01-01

    A new mixed valence molybdate, La 7 Mo 7 O 30 , first prepared by high energy ball milling, has been successfully synthesized by controlled hydrogen reduction of La 2 Mo 2 O 9 . Its original crystal structure was determined from X-ray and neutron powder diffraction (space group R 3 ; a = b = 17.0051(2) angstrom, c = 6.8607(1) angstrom; Z = 3; reliability factors: R p = 0.081, R wp = 0.091, χ 2 = 3.1, R Bragg = 0.049, R F = 0.033). It consists in the hexagonal stacking of individual cylinders of perovskite-type arrangement. These cylinders are built up from perovskite cages sharing corners in trans-position along their diagonal axis. Two different mixed-valence molybdenum sites coexist, with more (Mo +5.75 ) or less (Mo +4.5 ) distorted octahedral environments. Lanthanum atoms are located within the perovskite cages and around them, very close to their regular positions in the perovskite structure. Lanthanum and molybdenum atoms thus form two rows of almost perfect cubes, shifted from each other by c/2. An electron microscopy study revealed the defect-free cationic and octahedral arrangements in the (a,b) plane

  19. New manufacturing method for Fe-Si magnetic powders using modified pack-cementation process

    Science.gov (United States)

    Byun, Ji Young; Kim, Jang Won; Han, Jeong Whan; Jang, Pyungwoo

    2013-03-01

    This paper describes a new method for making Fe-Si magnetic powders using a pack-cementation process. It was found that Fe-Si alloy powders were formed by a reaction of the pack mixture of Fe, Si, NaF, and Al2O3 powders at 900 °C for 24 h under a hydrogen atmosphere. Separation of the Fe-Si alloy powders was dependent on the particle size of the Fe powders in the pack. For small Fe powders, magnetic separation in a medium of strong alkali solution was recommended. But, for relatively larger Fe powders, the Fe-Si alloy powders were easily separated from Al2O3 powders using a magnet in air atmosphere. The Si content in the Fe-Si magnetic powders were easily controlled by changing the weight ratio of Si to (Si+Fe) in the pack.

  20. Neutron powder diffraction investigation of magnetic structure and spin reorientation transition of HoFe{sub 1-x}Cr{sub x}O{sub 3} solid solutions

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xinzhi [Department of Nuclear Physics, China Institute of Atomic Energy, Beijing 102413 (China); Hao, Lijie, E-mail: haolijie@ciae.ac.cn [Department of Nuclear Physics, China Institute of Atomic Energy, Beijing 102413 (China); Liu, Yuntao; Ma, Xiaobai; Meng, Siqin; Li, Yuqing; Gao, Jianbo; Guo, Hao; Han, Wenze; Sun, Kai; Wu, Meimei [Department of Nuclear Physics, China Institute of Atomic Energy, Beijing 102413 (China); Chen, Xiping; Xie, Lei [Institute of Nuclear Physics and Chemistry, CAEP, Mianyang 621900 (China); Klose, Frank [Australian Nuclear Science and Technology Organization, Lucas Heights, New South Wales 2234 (Australia); Department of Physics and Materials Science, The City University of Hong Kong, Hong Kong (China); Chen, Dongfeng, E-mail: dongfeng@ciae.ac.cn [Department of Nuclear Physics, China Institute of Atomic Energy, Beijing 102413 (China)

    2016-11-01

    Orthoferrite solid solution HoFe{sub 1−x}Cr{sub x}O{sub 3} (x=0, 0.2,…,1.0) was synthesized via solid state reaction methods. The crystal structure, magnetism and spin reorientation properties of this system were investigated by X-ray diffraction, neutron powder diffraction and magnetic measurements. For compositions of x≤0.6, the system exhibits similar magnetic properties to HoFeO{sub 3}. With increasing Cr-doping, the system adopts a Γ{sub 4}(G{sub x}A{sub y}F{sub z}) magnetic configuration with a decreased Neel temperature from 640 K to 360 K. A Γ{sub 42} spin reorientation of Fe(Cr){sup 3+} was also observed in this system with an increase in transition temperature from 56 K to about 200 K due to competition between the Fe(Cr)–Fe(Cr) and Ho–Fe(Cr) interactions. For the x≥0.8, the system behaves more like HoCrO{sub 3} which adopts a Γ{sub 2}(F{sub x}C{sub y}G{sub z}) configuration with no spin reorientation below the Neel temperature T{sub N}. Throughout the whole substitution range, we found that the saturated moment of Fe(Cr) was less than the ideal value for a free ion, which implies the existence of spin fluctuation in this system. A systematic magnetic structure variation with Cr-substitution is revealed by Rietveld refinement. A phase diagram combining the results of the magnetic measurements and neutron powder diffraction results was obtained. - Highlights: • With Cr-substitution in the HoFe{sub 1−x}Cr{sub x}O{sub 3} system, A Γ{sub 42} spin reorientation of Fe(Cr){sup 3+} was observed with an increase in transition temperature from 56 K to about 200 K for x=0−0.6. • The saturated moment of Fe(Cr) position was found to be systematically less than the ideal value of free ion, and thus implies the presence of spin quantum fluctuation. • A composition–temperature phase diagram throughout x=0–1 for HoFe{sub 1−x}Cr{sub x}O{sub 3} system was established.

  1. Standard test method for verifying the alignment of X-Ray diffraction instrumentation for residual stress measurement

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This test method covers the preparation and use of a flat stress-free test specimen for the purpose of checking the systematic error caused by instrument misalignment or sample positioning in X-ray diffraction residual stress measurement, or both. 1.2 This test method is applicable to apparatus intended for X-ray diffraction macroscopic residual stress measurement in polycrystalline samples employing measurement of a diffraction peak position in the high-back reflection region, and in which the θ, 2θ, and ψ rotation axes can be made to coincide (see Fig. 1). 1.3 This test method describes the use of iron powder which has been investigated in round-robin studies for the purpose of verifying the alignment of instrumentation intended for stress measurement in ferritic or martensitic steels. To verify instrument alignment prior to stress measurement in other metallic alloys and ceramics, powder having the same or lower diffraction angle as the material to be measured should be prepared in similar fashion...

  2. Process Parameters on the Crystallization and Morphology of Hydroxyapatite Powders Prepared by a Hydrolysis Method

    Science.gov (United States)

    Wang, Moo-Chin; Hon, Min-Hsiung; Chen, Hui-Ting; Yen, Feng-Lin; Hung, I.-Ming; Ko, Horng-Huey; Shih, Wei-Jen

    2013-07-01

    The effects of process parameters on the crystallization and morphology of hydroxyapatite (Ca10(PO4)6(OH)2, HA) powders synthesized from dicalcium phosphate dihydrate (CaHPO4·2H2O, DCPD) using a hydrolysis method have been investigated. X-ray diffraction (XRD), Fourier-transform infrared (FT-IR) spectra, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and selected area electron diffraction (SAED) were used to characterize the synthesized powders. When DCPD underwent hydrolysis in 2.5 NaOH solution (Na(aq)) at 303 K to 348 K (30 °C to 75 °C) for 1 hour, the XRD results revealed that HA was obtained for all the as-dried samples. The SEM morphology of the HA powders for DCPD hydrolysis produced at 348 K (75 °C) shows regular alignment and a short rod shape with a size of 200 nm in length and 50 nm in width. With DCPD hydrolysis in 2.5 M NaOH(aq) holding at 348 K (75 °C) for 1 to 24 hours, XRD results demonstrated that all samples were HA and no other phases could be detected. Moreover, the XRD results also show that all the as-dried powders still maintained the HA structure when DCPD underwent hydrolysis in 0.1 to 5 M NaOH(aq) at 348 K (75 °C) for 1 hour. Otherwise, the full transformation from HA to octa-calcium phosphate (OCP, Ca8H2(PO4)6·5H2O) occurred when hydrolysis happened in 10 M NaOH(aq). FT-IR spectra analysis revealed that some carbonated HA (Ca10(PO4)6(CO3), CHA) had formed. The SEM morphology results show that the 60 to 65 nm width of the uniformly long rods with regular alignment formed in the HA powder aggregates when DCPD underwent hydrolysis in 2.5 M NaOH(aq) at 348 K (75 °C) for 1 hour.

  3. Analysis of a nanocrystalline polymer dispersion of ebselen using solid-state NMR, Raman microscopy, and powder X-ray diffraction.

    Science.gov (United States)

    Vogt, Frederick G; Williams, Glenn R

    2012-07-01

    Nanocrystalline drug-polymer dispersions are of significant interest in pharmaceutical delivery. The purpose of this work is to demonstrate the applicability of methods based on two-dimensional (2D) and multinuclear solid-state NMR (SSNMR) to a novel nanocrystalline pharmaceutical dispersion of ebselen with polyvinylpyrrolidone-vinyl acetate (PVP-VA), after initial characterization with other techniques. A nanocrystalline dispersion of ebselen with PVP-VA was prepared and characterized by powder X-ray diffraction (PXRD), confocal Raman microscopy and mapping, and differential scanning calorimetry (DSC), and then subjected to detailed 1D and 2D SSNMR analysis involving ¹H, ¹³C, and ⁷⁷Se isotopes and ¹H spin diffusion. PXRD was used to show that dispersion contains nanocrystalline ebselen in the 35-60 nm size range. Confocal Raman microscopy and spectral mapping were able to detect regions where short-range interactions may occur between ebselen and PVP-VA. Spin diffusion effects were analyzed using 2D SSNMR experiments and are able to directly detect interactions between ebselen and the surrounding PVP-VA. The methods used here, particularly the 2D SSNMR methods based on spin diffusion, provided detailed structural information about a nanocrystalline polymer dispersion of ebselen, and should be useful in other studies of these types of materials.

  4. Synthesis of nano-sized amorphous boron powders through active dilution self-propagating high-temperature synthesis method

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jilin [The State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China); Gu, Yunle [School of Material Science and Engineering, Wuhan Institute of Technology, Wuhan 430073 (China); Li, Zili [The State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China); Wang, Weimin, E-mail: wangwm@hotmail.com [The State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China); Fu, Zhengyi [The State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China)

    2013-06-01

    Graphical abstract: Nano-sized amorphous boron powders were synthesized by active dilution self-propagating high-temperature synthesis (SHS) method. The effects of endothermic reaction rate, the possible chemical reaction mechanism and active dilution model for synthesis of the product were also discussed. Highlights: ► Nano-sized amorphous boron powders were synthesized by active dilution self-propagating high-temperature synthesis method. ► The morphology, particle size and purity of the samples could be effectively controlled via changing the endothermic rate. ► The diluter KBH{sub 4} played an important role in active dilution synthesis of amorphous nano-sized boron powders. ► The active dilution method could be further popularized and become a common approach to prepare various inorganic materials. - Abstract: Nano-sized amorphous boron powders were synthesized by active dilution self-propagating high-temperature synthesis (SHS) method at temperatures ranging from 700 °C to 850 °C in a SHS furnace using Mg, B{sub 2}O{sub 3} and KBH{sub 4} as raw materials. Samples were characterized by X-ray powder diffraction (XRD), Laser particle size analyzer, Fourier transform infrared spectra (FTIR), X-ray energy dispersive spectroscopy (EDX), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high-resolution transmission TEM (HRTEM). The boron powders demonstrated an average particle size of 50 nm with a purity of 95.64 wt.%. The diluter KBH{sub 4} played an important role in the active dilution synthesis of amorphous nano-sized boron powders. The effects of endothermic reaction rate, the possible chemical reaction mechanism and active dilution model for synthesis of the product were also discussed.

  5. Synthesis of nano-sized amorphous boron powders through active dilution self-propagating high-temperature synthesis method

    International Nuclear Information System (INIS)

    Wang, Jilin; Gu, Yunle; Li, Zili; Wang, Weimin; Fu, Zhengyi

    2013-01-01

    Graphical abstract: Nano-sized amorphous boron powders were synthesized by active dilution self-propagating high-temperature synthesis (SHS) method. The effects of endothermic reaction rate, the possible chemical reaction mechanism and active dilution model for synthesis of the product were also discussed. Highlights: ► Nano-sized amorphous boron powders were synthesized by active dilution self-propagating high-temperature synthesis method. ► The morphology, particle size and purity of the samples could be effectively controlled via changing the endothermic rate. ► The diluter KBH 4 played an important role in active dilution synthesis of amorphous nano-sized boron powders. ► The active dilution method could be further popularized and become a common approach to prepare various inorganic materials. - Abstract: Nano-sized amorphous boron powders were synthesized by active dilution self-propagating high-temperature synthesis (SHS) method at temperatures ranging from 700 °C to 850 °C in a SHS furnace using Mg, B 2 O 3 and KBH 4 as raw materials. Samples were characterized by X-ray powder diffraction (XRD), Laser particle size analyzer, Fourier transform infrared spectra (FTIR), X-ray energy dispersive spectroscopy (EDX), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high-resolution transmission TEM (HRTEM). The boron powders demonstrated an average particle size of 50 nm with a purity of 95.64 wt.%. The diluter KBH 4 played an important role in the active dilution synthesis of amorphous nano-sized boron powders. The effects of endothermic reaction rate, the possible chemical reaction mechanism and active dilution model for synthesis of the product were also discussed

  6. Phase transitions of Cu.sub.3+x./sub.Si observed by temperature-dependent x-ray powder diffraction

    Czech Academy of Sciences Publication Activity Database

    Correa, Cinthia Antunes; Poupon, Morgane; Kopeček, Jaromír; Král, Robert; Zemenová, Petra; Lecourt, J.; Barrier, N.; Brázda, Petr; Klementová, Mariana; Palatinus, Lukáš

    2017-01-01

    Roč. 91, Dec (2017), s. 129-139 ISSN 0966-9795 R&D Projects: GA ČR GC15-08842J Institutional support: RVO:68378271 Keywords : X-ray powder diffraction * differential scanning calorimetry * phase transitions * Cu3+xSi Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 3.140, year: 2016

  7. Structural and microstructural changes during anion exchange of CoAl layered double hydroxides: an in situ X-ray powder diffraction study

    DEFF Research Database (Denmark)

    Johnsen, Rune; Krumeich, Frank; Norby, Poul

    2010-01-01

    Anion-exchange processes in cobalt-aluminium layered double hydroxides (LDHs) were studied by in situ synchrotron X-ray powder diffraction (XRPD). The processes investigated were CoAl-CO3 CoAl-Cl CoAl-CO3, CoAl-Cl CoAl-NO3 and CoAl-CO3 CoAl-SO4. The XRPD data show that the CoAl-CO3 CoAl-Cl process...

  8. Solving crystal structures from powder data. I. The role of the prior information in the two-stage method

    International Nuclear Information System (INIS)

    Altomare, A.; Carrozzini, B.; Giacovazzo, C.; Guagliardi, A.; Moliterni, A.G.G.; Rizzi, R.

    1996-01-01

    For pt.II see ibid., p.674-81, 1996. The principal limitation of the diffraction methods for crystal structure analysis from powder data is originated by the collapse of the three-dimensional reciprocal space into the one dimension of the powder diffraction pattern. The degradation of the information can make difficult even the solution of small crystal structures and can generate inefficiencies in the least-squares methods devoted to crystal structure refinement. In this paper, the current two-stage procedures, the first stage dedicated to powder-pattern decomposition and the second to direct phasing of powder data, are analysed. It is shown that in the first stage such procedures disregard a large amount of information that can become available during the process of crystal structure solution and analysis. The use of such information is essential for making direct-methods procedures more robust and for improving the accuracy of the least-squares techniques. The performances of EXTRA [Altomare, Burla, Cascarano, Giacovazzo, Guagliardi, Moliterni and Polidori (1995). J. Appl. Cryst. 28, 842-846], a program for full-pattern decomposition based on the Le Bail algorithm, and of SIRPOW.92 [Altomare, Burla, Cascarano, Giacovazzo, Guagliardi, Polidori and Camalli (1994). J. Appl. Cryst. 27, 435-436], a direct-methods program optimized for powder data, are discussed in order to offer to the reader a logical pathway for the analysis of the traditional techniques and for the proposition of a new approach. It is shown that pattern-decomposition programs based on the Le Bail algorithm are able to exploit the prior information in a more effective way than Pawley-method-based decomposition programs. (orig.)

  9. Photocatalytic Activity in CH3CN Related to the Surface Properties of TiO2 Powders Prepared by Sol-Gel Method

    OpenAIRE

    Bettoni, Marta; Candori, Pietro; Marmottini, Fabio; Perenze, Nicoletta; Rol, Cesare; Sebastiani, Giovanni V.; Vecchiocattivi, Franco

    2009-01-01

    Some TiO2 powders, prepared from titanium(IV)tetraisopropoxide by the sol-gel method and thermally treated between 100 and 1000∘C, have been characterized by X-ray powder diffraction and by nitrogen adsorption and desorption at 77 K to calculate the BET-specific surface area, from which the micropore volume and the external surface area can be derived. The photocatalytic activity (ka) of the above powders has been evaluated considering the TiO2-sensitized photo-oxidation of 4-methoxybenzyl al...

  10. Obtaining aluminas from the thermal decomposition of their different precursors: An {sup 27}Al MAS NMR and X-ray powder diffraction studies

    Energy Technology Data Exchange (ETDEWEB)

    Chagas, L.H.; De Carvalho, G.S.G. [Universidade Federal de Juiz de Fora, Departamento de Química, Grupo de Físico-Química de Sólidos e Interfaces, 36036-330 Juiz de Fora, MG (Brazil); San Gil, R.A.S. [Universidade Federal do Rio de Janeiro, Instituto de Química, 21949-900 Rio de Janeiro, RJ (Brazil); Chiaro, S.S.X. [PETROBRAS-CENPES, 21941-915 Rio de Janeiro, RJ (Brazil); Leitão, A.A. [Universidade Federal de Juiz de Fora, Departamento de Química, Grupo de Físico-Química de Sólidos e Interfaces, 36036-330 Juiz de Fora, MG (Brazil); Diniz, R., E-mail: renata.diniz@ufjf.edu.br [Universidade Federal de Juiz de Fora, Departamento de Química, Grupo de Físico-Química de Sólidos e Interfaces, 36036-330 Juiz de Fora, MG (Brazil)

    2014-01-01

    Graphical abstract: - Highlights: • We synthesized three precursors of alumina from different methods. • The calcination of the precursors generated several alumina polymorphs. • XRD and NMR were used for structural investigation of the polymorphs. • The synthesis route determines the structural and textural properties of the solids. - Abstract: A commercial sample of Boehmite was used as precursor of alumina polymorphs. For comparison, three other precursors were synthesized from different methods. Particularly, the use of excess of urea promoted a very crystalline form of basic aluminum carbonate. The characteristics of the four precursors were investigated by thermal, vibrational and X-ray powder diffraction (XRD) analysis. Additionally, the nuclear magnetic resonance, with magic angle spinning ({sup 27}Al MAS NMR), was used to verify the coordination of aluminum cations. Each precursor was calcined at various temperatures generating alumina polymorphs, which were structurally analyzed by XRD and {sup 27}Al MAS NMR. Due to interest in catalysis supports, special attention was given to the γ-Al{sub 2}O{sub 3} phase, which in addition to structural investigation was subjected to textural analysis. The results showed that, from different synthesis procedures and common route of calcination, one can obtain materials with the same composition but with different structural and textural properties, which in turn can significantly influence the performance of a supported catalyst.

  11. Quantifying low amorphous or crystalline amounts of alpha-lactose-monohydrate using X-ray powder diffraction, near-infrared spectroscopy, and differential scanning calorimetry.

    Science.gov (United States)

    Fix, I; Steffens, K J

    2004-05-01

    Efficient and accurate quantification of low amorphous and crystalline contents within pharmaceutical materials still remains a challenging task in the pharmaceutical industry. Since X-ray powder diffraction (XRPD) equipment has improved in recent years, our aim was 1) to investigate the possibility of substantially lowering the detection limits of amorphous or crystalline material to about 1% or 0.5% w/w respectively by applying conventional Bragg Brentano optics, combined with a fast and simple evaluation technique; 2) to perform these measurements within a short time to make it suitable for routine analysis; and 3) to subject the same data sets to a partial least squares regression (PLSR) in order to investigate whether it is possible to improve accuracy and precision compared to the standard integration method. Near-infrared spectroscopy (NIRS) and differential scanning calorimetry (DSC) were chosen as reference method. As model substance, alpha lactose monohydrate was chosen to create calibration curves based on predetermined mixtures of highly crystalline and amorphous substance. In contrast to DSC, XRPD and NIRS revealed an excellent linearity, precision, and accuracy with the percent of crystalline amount and a detectability down to about 0.5% w/w. Chemometric evaluation (partial least squares regression) applied to the XRPD data further improved the quality of our calibration.

  12. In-house characterization of protein powder

    DEFF Research Database (Denmark)

    Hartmann, Christian Grundahl; Nielsen, Ole Faurskov; Ståhl, Kenny

    2010-01-01

    X-ray powder diffraction patterns of lysozyme and insulin were recorded on a standard in-house powder diffractometer. The experimental powder diffraction patterns were compared with patterns calculated from Protein Data Bank coordinate data. Good agreement was obtained by including straightforward...... to include calculated H-atom positions did not improve the overall fit and was abandoned. The method devised was shown to be a quick and convenient tool for distinguishing precipitates and polymorphs of proteins....

  13. Functional coordination polymers and MOFs from reactions of the lanthanides and barium with azole ligands. Synthesis and characterization with a focus on structure determination from X-ray powder diffraction data

    International Nuclear Information System (INIS)

    Rybak, Jens-Christoph

    2012-01-01

    of this thesis. A method is presented, which allows, by indexing a diffractogram, intensity extraction and structure solution by charge flipping, to solve the structure of a material, ab initio, from X-ray powder diffraction data exclusively. Moreover it is shown how to refine structures with a high amount of weakly scattering atoms, using rigid body constraints. The structure solutions of 3 ∞ [Ga(Tz) 2 ], 3 ∞ [Sr(Im) 2 ]:Ce and 3 ∞ [Yb(Im) 3 ]ImH from X-ray powder diffraction data are further examples for the successful application of the method presented within this thesis.

  14. New powder compaction method using a styrene foam

    International Nuclear Information System (INIS)

    Kinemuchi, Y.; Takata, A.; Ishizaki, K.

    1999-01-01

    In general, metallic and ceramic powder compacts for sintering are shaped by uni-axial pressing or cold isostatic pressing (CIPing). Since metal or rubber is used as dies or moulds, it is difficult to form complicated shapes and flat disks, i.e., the ratio of diameter / thickness more than 50, by using uni-axial or CIPing. Rubber moulding, a moulding method with a rubber bag, can not press powder uniformly into flat disks because rubber deforms significantly. To solve this problem, we developed a new shaping technique to obtain complicated or thin flat shape by using styrene foam, which is cheap and has good machinability. Plastic foams such as styrene and acrylic foam contain many pores, and shrink uniformly by applying external pressure when the pores are collapsed. In this study, shrinking behavior of styrene and acrylic rubber moulds related to CIPing pressure was investigated. The experimental results show that the plastic foams shrink uniformly and the plastic deformation is linearly increased as CIP pressure increases. Copyright (1999) AD-TECH - International Foundation for the Advancement of Technology Ltd

  15. Neutron diffraction utilizing the T-O-F method

    Energy Technology Data Exchange (ETDEWEB)

    Niimura, N [Tohoku Univ., Sendai (Japan). Lab. of Nuclear Science

    1974-12-01

    Characteristic features of the TOF (time of flight) neutron diffraction are summarized. In this method, i) all the reciprocal points on the rod passing through the origin in the reciprocal space can be scanned by each burst of white neutrons, ii) it is easy to measure high index reflections at the large scattering angle, iii) each reflection is not affected by the higher-order harmonics, and iv) it is easy to measure the physical properties depending on the neutron wavelength. The pulse neutron generator as well as the data acquisition system in the Laboratory of Nuclear Science of Tohoku University is described. The TOF method seems to be very powerful if it is applied to accurate structure analysis. The data correction methods are discussed. The TOF method is prospective to the study of transient phenomena. In this method one can apply to the crystalline sample an external field pulsed with the same frequency as the neutrons. By using this method, the transient state of the polarization reversal of the ferroelectric NaNO/sub 2/ has been observed. The magnetically pulsed neutron TOF spectrometer is briefly introduced after a review of the chopper history.

  16. New methods for indexing multi-lattice diffraction data

    International Nuclear Information System (INIS)

    Gildea, Richard J.; Waterman, David G.; Parkhurst, James M.; Axford, Danny; Sutton, Geoff; Stuart, David I.; Sauter, Nicholas K.; Evans, Gwyndaf; Winter, Graeme

    2014-01-01

    A new indexing method is presented which is capable of indexing multiple crystal lattices from narrow wedges of data. The efficacy of this method is demonstrated with both semi-synthetic multi-lattice data and real multi-lattice data recorded from microcrystals of ∼1 µm in size. A new indexing method is presented which is capable of indexing multiple crystal lattices from narrow wedges of diffraction data. The method takes advantage of a simplification of Fourier transform-based methods that is applicable when the unit-cell dimensions are known a priori. The efficacy of this method is demonstrated with both semi-synthetic multi-lattice data and real multi-lattice data recorded from crystals of ∼1 µm in size, where it is shown that up to six lattices can be successfully indexed and subsequently integrated from a 1° wedge of data. Analysis is presented which shows that improvements in data-quality indicators can be obtained through accurate identification and rejection of overlapping reflections prior to scaling

  17. Investigation by laser induced breakdown spectroscopy, X-ray fluorescence and X-ray powder diffraction of the chemical composition of white clay ceramic tiles from Veliki Preslav

    International Nuclear Information System (INIS)

    Blagoev, K.; Grozeva, M.; Malcheva, G.; Neykova, S.

    2013-01-01

    The paper presents the results of the application of laser induced breakdown spectroscopy, X-ray fluorescence spectrometry, and X-ray powder diffraction in assessing the chemical and phase composition of white clay decorative ceramic tiles from the medieval archaeological site of Veliki Preslav, a Bulgarian capital in the period 893–972 AC, well-known for its original ceramic production. Numerous white clay ceramic tiles with highly varied decoration, produced for wall decoration of city's churches and palaces, were found during the archaeological excavations in the old capital. The examination of fourteen ceramic tiles discovered in one of the city's monasteries is aimed at characterization of the chemical profile of the white-clay decorative ceramics produced in Veliki Preslav. Combining different methods and comparing the obtained results provides complementary information regarding the white-clay ceramic production in Veliki Preslav and complete chemical characterization of the examined artefacts. - Highlights: ► LIBS, XRF and XRD analyses of medieval white-clay ceramic tiles fragments are done. ► Different elements and phases, presented in the ceramics fragments were determined. ► Differences in the tiles' raw material mineral composition are found. ► Information of the tiles' production process and the raw clay deposits is obtained

  18. Investigation by laser induced breakdown spectroscopy, X-ray fluorescence and X-ray powder diffraction of the chemical composition of white clay ceramic tiles from Veliki Preslav

    Energy Technology Data Exchange (ETDEWEB)

    Blagoev, K., E-mail: kblagoev@issp.bas.bg [Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee, 1784 Sofia (Bulgaria); Grozeva, M., E-mail: margo@issp.bas.bg [Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee, 1784 Sofia (Bulgaria); Malcheva, G., E-mail: bobcheva@issp.bas.bg [Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee, 1784 Sofia (Bulgaria); Neykova, S., E-mail: sevdalinaneikova@abv.bg [National Institute of Archaeology with Museum, Bulgarian Academy of Sciences, 2 Saborna, 1000 Sofia (Bulgaria)

    2013-01-01

    The paper presents the results of the application of laser induced breakdown spectroscopy, X-ray fluorescence spectrometry, and X-ray powder diffraction in assessing the chemical and phase composition of white clay decorative ceramic tiles from the medieval archaeological site of Veliki Preslav, a Bulgarian capital in the period 893–972 AC, well-known for its original ceramic production. Numerous white clay ceramic tiles with highly varied decoration, produced for wall decoration of city's churches and palaces, were found during the archaeological excavations in the old capital. The examination of fourteen ceramic tiles discovered in one of the city's monasteries is aimed at characterization of the chemical profile of the white-clay decorative ceramics produced in Veliki Preslav. Combining different methods and comparing the obtained results provides complementary information regarding the white-clay ceramic production in Veliki Preslav and complete chemical characterization of the examined artefacts. - Highlights: ► LIBS, XRF and XRD analyses of medieval white-clay ceramic tiles fragments are done. ► Different elements and phases, presented in the ceramics fragments were determined. ► Differences in the tiles' raw material mineral composition are found. ► Information of the tiles' production process and the raw clay deposits is obtained.

  19. Poly[μ-(1-azaniumylethane-1,1-diyl)- bis(hydrogen phosphonato)sodium]: A powder X-ray diffraction study

    International Nuclear Information System (INIS)

    Rukiah, M.; Assaad, T.

    2015-01-01

    The title two-dimensional coordination polymer, [Na(C2H8NO6P2)]n, was characterized using powder X-ray diffraction data and its structure refined using the Rietveld method. The asymmetric unit contains one Na(+) cation and one (1-azaniumylethane-1,1-diyl)bis(hydrogen phosphonate) anion. The central Na(+) cation exhibits distorted octahedral coordination geometry involving two deprotonated O atoms, two hydroxy O atoms and two double-bonded O atoms of the bisphosphonate anion. Pairs of sodium-centred octahedra share edges and the pairs are in turn connected to each other by the biphosphonate anion to form a two-dimensional network parallel to the (001) plane. The polymeric layers are connected by strong O-H...O hydrogen bonding between the hydroxy group and one of the free O atoms of the bisphosphonate anion to generate a three-dimensional network. Further stabilization of the crystal structure is achived by N-H...O and O-H...O hydrogen bonding.(author)

  20. Pressure dependence of hydrogen bonding in metal deuteroxides: a neutron powder diffraction study of Mn(OD)2 and β-Co(OD)2

    International Nuclear Information System (INIS)

    Parise, J.B.; Theroux, B.; Li, R.; Loveday, J.S.; Marshall, W.G.; Klotz, S.

    1998-01-01

    The structures of deuterated pyrochroite, Mn(OD) 2 and β-Co(OD) 2 have been refined using the Rietveld method and neutron powder diffraction data collected in an opposed-anvil high pressure (Paris-Edinburgh) cell from room pressure to 9 GPa. The equation of state for Mn(OD) 2 was determined (K=41(3) GPa for fixed K'=4.7) and found to be consistent with previous studies of the isostructural brucite, Mg(OD) 2 . The compressibility of β-Co(OD) 2 on the other hand is apparently anomalous. The c-axis initially decreases at 3 times the rate of decrease of the a-axis; the ratio decreases to about 1.5 at an estimated 6 GPa before increasing again beyond this pressure. There is no obvious corresponding anomaly in the details of the atomic structure. In both materials there is an increase in the D-site disorder with pressure. A split-site model for the D-positions best fits the data at pressures above 8 GPa. There is no statistically significant increase in the O-D interatomic distance at increased pressure while the hydrogen bonding interaction D..O appears to increase as this distance decreases and the O-D..O angle increases. The intramolecular O-D bond valences, determined indirectly from the intermolecular D..O distances, decrease steadily for both materials as pressure is increased. (orig.)

  1. Method of manufacturing mixed stock powders for nuclear fuel elements

    International Nuclear Information System (INIS)

    Hirayama, Satoshi.

    1980-01-01

    Purpose: To alleviate the limit of the present reactor operating conditions by uniformly mixing an additive to the main content as an uranium dioxide or mixture of the uranium dioxide with plutonium dioxide. Method: A mixed stock powder is obtained by adding an additive of at least two of aluminium oxide, beryllium oxide, calcium oxide, magnesium oxide, silicon oxide, sodium oxide, potassium oxide, phosphorus oxide, titanium oxide and iron oxide to suspension having ammonia water as dispersion medium to start the deposition of precipitation at a step of precipitating ammonium diuranate or plutionium hydroxide of a main content of uranium dioxide or mixture of uranium dioxide and plutonium dioxide and deposited precipitate is calcinated and reduced. (Yoshihara, H.)

  2. Preparation and Characterization of Nano-structured Ceramic Powders Synthesized by Emulsion Combustion Method

    International Nuclear Information System (INIS)

    Takatori, Kazumasa; Tani, Takao; Watanabe, Naoyoshi; Kamiya, Nobuo

    1999-01-01

    The emulsion combustion method (ECM), a novel powder production process, was originally developed to synthesize nano-structured metal-oxide powders. Metal ions in the aqueous droplets were rapidly oxidized by the combustion of the surrounding flammable liquid. The ECM achieved a small reaction field and a short reaction period to fabricate the submicron-sized hollow ceramic particles with extremely thin wall and chemically homogeneous ceramic powder. Alumina, zirconia, zirconia-ceria solid solutions and barium titanate were synthesized by the ECM process. Alumina and zirconia powders were characterized to be metastable in crystalline phase and hollow structure. The wall thickness of alumina was about 10 nm. The zirconia-ceria powders were found to be single-phase solid solutions for a wide composition range. These powders were characterized as equiaxed-shape, submicron-sized chemically homogeneous materials. The powder formation mechanism was investigated through the synthesis of barium titanate powder with different metal sources

  3. Low-Pressure and Low-Temperature Hydriding-Pulverization-Dehydriding Method for Producing Shape Memory Alloy Powders

    Science.gov (United States)

    Murguia, Silvia Briseño; Clauser, Arielle; Dunn, Heather; Fisher, Wendy; Snir, Yoav; Brennan, Raymond E.; Young, Marcus L.

    2018-04-01

    Shape memory alloys (SMAs) are of high interest as active, adaptive "smart" materials for applications such as sensors and actuators due to their unique properties, including the shape memory effect and pseudoelasticity. Binary NiTi SMAs have shown the most desirable properties, and consequently have generated the most commercial success. A major challenge for SMAs, in particular, is their well-known compositional sensitivity. Therefore, it is critical to control the powder composition and morphology. In this study, a low-pressure, low-temperature hydriding-pulverization-dehydriding method for preparing well-controlled compositions, size, and size distributions of SMA powders from wires is presented. Starting with three different diameters of as-drawn martensitic NiTi SMA wires, pre-alloyed NiTi powders of various well-controlled sizes are produced by hydrogen charging the wires in a heated H3PO4 solution. After hydrogen charging for different charging times, the wires are pulverized and subsequently dehydrided. The wires and the resulting powders are characterized using scanning electron microscopy, differential scanning calorimetry, and X-ray diffraction. The relationship between the wire diameter and powder size is investigated as a function of hydrogen charging time. The rate of diameter reduction after hydrogen charging of wire is also examined. Finally, the recovery behavior due to the shape memory effect is investigated after dehydriding.

  4. Room temperature ferromagnetism in Eu-doped ZnO nanoparticulate powders prepared by combustion reaction method

    International Nuclear Information System (INIS)

    Franco, A.; Pessoni, H.V.S.; Soares, M.P.

    2014-01-01

    Nanoparticulate powders of Eu-doped ZnO with 1.0, 1.5, 2.0 and 3.0 at% Eu were synthesized by combustion reaction method using zinc nitrate, europium nitrate and urea as fuel without subsequent heat treatments. X-ray diffraction patterns (XRD) of all samples showed broad peaks consistent with the ZnO wurtzite structure. The absence of extra reflections in the diffraction patterns ensures the phase purity, except for x=0.03 that exhibits small reflection corresponding to Eu 2 O 3 phase. The average crystallite size determined from the most prominent (1 0 1) peak of the diffraction using Scherrer's equation was in good agreement with those determined by transmission electron microscopy (TEM); being ∼26 nm. The magnetic properties measurements were performed using a vibrating sample magnetometer (VSM) in magnetic fields up to 2.0 kOe at room temperature. The hysteresis loops, typical of magnetic behaviors, indicating that the presence of an ordered magnetic structure can exist in the Eu-doped ZnO wurtzite structure at room temperature. The room temperature ferromagnetism behavior increases with the Eu 3+ doping concentration. All samples exhibited the same Curie temperature (T C ) around ∼726 K, except for x=0.01; T C ∼643 K. High resolution transmission electron microscopy (HRTEM) images revealed defects/strain in the lattice and grain boundaries of Eu-doped ZnO nanoparticulate powders. The origin of room temperature ferromagnetism in Eu-doped ZnO nanoparticulate powders was discussed in terms of these defects, which increase with the Eu 3+ doping concentration. - Highlights: • Room-temperature ferromagnetism. • Structural and magnetic properties of nanoparticulate powders of Zn 1−x Eu x O. • Combustion reaction method

  5. Nanosized lead lanthanum titanate (PLT) ceramic powders synthesized by the oxidant peroxo method

    Energy Technology Data Exchange (ETDEWEB)

    Camargo, Emerson R. [LIEC-Laboratorio Interdisciplinar de Eletroquimica e Ceramica, Department of Chemistry, UFSCar-Federal University of Sao Carlos, Rod.Washingtin Luis km 235, CP 676, Sao Carlos SP 13565-9905 (Brazil)], E-mail: camargo@ufscar.br; Barrado, Cristiano M. [LIEC-Laboratorio Interdisciplinar de Eletroquimica e Ceramica, Department of Chemistry, UFSCar-Federal University of Sao Carlos, Rod.Washingtin Luis km 235, CP 676, Sao Carlos SP 13565-9905 (Brazil); Ribeiro, Caue [EMBRAPA Instrumentacao Agropecuaria, Rua XV de Novembro 1452, Sao Carlos SP 13560-970 (Brazil)], E-mail: caue@cnpdia.embrapa.br; Longo, Elson [Department of Biochemistry, Chemistry Institute of Araraquara, UNESP-Sao Paulo State University, Rua Francisco Degni, CP 355, Araraquara SP 14801-907 (Brazil)], E-mail: elson@iq.unesp.br; Leite, Edson R. [LIEC-Laboratorio Interdisciplinar de Eletroquimica e Ceramica, Department of Chemistry, UFSCar-Federal University of Sao Carlos, Rod.Washingtin Luis km 235, CP 676, Sao Carlos SP 13565-9905 (Brazil)], E-mail: derl@power.ufscar.br

    2009-05-05

    For the first time it is reported the synthesis of lead titanate modified with rare earth by the oxidant-peroxo method (OPM). Lanthanum was added up to 20% in mol through the dissolution of lanthanum oxide in nitric acid, followed by the addition of a solution of lead and lanthanum nitrate into an aqueous solution of titanium peroxo complexes. The amorphous precipitate formed was heat-treated at different temperatures in the range from 400 to 900 deg. C for crystallization. Powders were characterized by Raman spectroscopy and X-ray diffraction. Tetragonal perovskite structure was observed for the samples up to 15% of lanthanum substitution and cubic perovskite for sample with 20% of lanthanum. Crystallographic domains calculated by Scherrer equation showing a probable suppression of the crystallite growth in function of lanthanum content. It was observed shifting to lower frequencies of Raman modes in the range between 100 and 400 cm{sup -1} and the vanishing of the A1(2TO) and E(1LO) modes could be attributed to transition phase from tetragonal to cubic. Electronic microscopy image revealed that the powders annealed at height temperature are spherical with sharp size distribution.

  6. Nanosized lead lanthanum titanate (PLT) ceramic powders synthesized by the oxidant peroxo method

    International Nuclear Information System (INIS)

    Camargo, Emerson R.; Barrado, Cristiano M.; Ribeiro, Caue; Longo, Elson; Leite, Edson R.

    2009-01-01

    For the first time it is reported the synthesis of lead titanate modified with rare earth by the oxidant-peroxo method (OPM). Lanthanum was added up to 20% in mol through the dissolution of lanthanum oxide in nitric acid, followed by the addition of a solution of lead and lanthanum nitrate into an aqueous solution of titanium peroxo complexes. The amorphous precipitate formed was heat-treated at different temperatures in the range from 400 to 900 deg. C for crystallization. Powders were characterized by Raman spectroscopy and X-ray diffraction. Tetragonal perovskite structure was observed for the samples up to 15% of lanthanum substitution and cubic perovskite for sample with 20% of lanthanum. Crystallographic domains calculated by Scherrer equation showing a probable suppression of the crystallite growth in function of lanthanum content. It was observed shifting to lower frequencies of Raman modes in the range between 100 and 400 cm -1 and the vanishing of the A1(2TO) and E(1LO) modes could be attributed to transition phase from tetragonal to cubic. Electronic microscopy image revealed that the powders annealed at height temperature are spherical with sharp size distribution.

  7. Effect of synthesis conditions on the preparation of YIG powders via co-precipitation method

    International Nuclear Information System (INIS)

    Rashad, M.M.; Hessien, M.M.; El-Midany, A.; Ibrahim, I.A.

    2009-01-01

    Yttrium iron garnet (YIG) (Y 3 Fe 5 O 12 ) powders have been synthesized through a co-precipitation method in the presence of sodium bis(2-ethylhexylsulfosuccinate), AOT as an anionic surfactant. The garnet precursors produced were obtained from aqueous iron and yttrium nitrates mixtures using 5 M sodium hydroxide at pH 10. A statistical Box-Behnken experimental design was used to investigate the effect of the main parameters (i.e. AOT surfactant concentration, annealing time and temperature) on YIG powder formation, crystallite size, morphology and magnetic properties. YIG particles were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), and vibrating sample magnetometer. XRD revealed that the formation of single cubic phase of YIG was temperature dependent and increased by increasing the annealing temperature from 800 to 1200 o C. SEM micrographs showed that the addition of AOT surfactant promoted the microstructure of YIG in crystalline cubic-like structure. The magnetic properties were sensitive to the synthesis variables of annealing temperature, time and AOT surfactant concentration. The maximum saturation magnetization (28.13 emu/g), remanence magnetization (21.57 emu/g) and coercive force (703 Oe) were achieved at an annealing temperature of 1200 o C, time 2 h and 500 ppm of AOT surfactant concentration.

  8. Effects of milling method and calcination condition on phase and morphology characteristics of Mg4Nb2O9 powders

    International Nuclear Information System (INIS)

    Wongmaneerung, R.; Sarakonsri, T.; Yimnirun, R.; Ananta, S.

    2006-01-01

    Magnesium niobate, Mg 4 Nb 2 O 9 , powders has been synthesized by a solid-state reaction. Both conventional ball- and rapid vibro-milling have been investigated as milling methods, with the formation of the Mg 4 Nb 2 O 9 phase investigated as a function of calcination conditions by DTA and XRD. The particle size distribution of the calcined powders was determined by laser diffraction technique, while morphology, crystal structure and phase composition were determined via a combination of SEM, TEM and EDX techniques. The type of milling method together with the designed calcination condition was found to show a considerable effect on the phase and morphology evolution of the calcined Mg 4 Nb 2 O 9 powders. It is seen that optimization of calcination conditions can lead to a single-phase Mg 4 Nb 2 O 9 in both milling methods. However, the formation temperature and dwell time for single-phase Mg 4 Nb 2 O 9 powders were lower with the rapid vibro-milling technique

  9. 1-(2-furoyl)-3,3-(diphenyl)thiourea: spectroscopic characterization and structural study from X-ray powder diffraction using simulated annealing

    Energy Technology Data Exchange (ETDEWEB)

    Estevez H, O.; Duque, J. [Universidad de La Habana, Instituto de Ciencia y Tecnologia de Materiales, 10400 La Habana (Cuba); Rodriguez H, J. [UNAM, Instituto de Investigaciones en Materiales, 04510 Mexico D. F. (Mexico); Yee M, H., E-mail: oestevezh@yahoo.com [Instituto Politecnico Nacional, Escuela Superior de Fisica y Matematicas, 07738 Mexico D. F. (Mexico)

    2015-07-01

    1-Furoyl-3,3-diphenylthiourea (FDFT) was synthesized, and characterized by Ftir, {sup 1}H and {sup 13}C NMR and ab initio X-ray powder structure analysis. FDFT crystallizes in the monoclinic space group P2{sub 1} with a = 12.691(1), b = 6.026(2), c = 11.861(1) A, β = 117.95(2) and V = 801.5(3) A{sup 3}. The crystal structure has been determined from laboratory X-ray powder diffraction data using direct space global optimization strategy (simulated annealing) followed by the Rietveld refinement. The thiourea group makes a dihedral angle of 73.8(6) with the furoyl group. In the crystal structure, molecules are linked by van der Waals interactions, forming one-dimensional chains along the a axis. (Author)

  10. The equation of state of PbTiO sub 3 up to 37 GPa: a synchrotron x-ray powder diffraction study

    CERN Document Server

    Sani, A; Levy, D

    2002-01-01

    High-pressure synchrotron x-ray powder diffraction patterns were collected using ID09 of ESRF (Grenoble, France) for a powder sample of PbTiO sub 3 , placed in a diamond anvil cell. The patterns were collected at room temperature using nitrogen (up to 37 GPa) and methanol-ethanol solution (up to 7 GPa) as pressure-transmitting media. The bulk moduli were calculated for the first time using the Vinet equation of state and they were compared to those of isostructural compounds. The trend of the spontaneous polarization as a function of pressure confirms that the ferroelectric-paraelectric phase transition at 11.2 GPa possesses a second-order character.

  11. Combining selective sequential extractions, X-Ray Absorption Spectroscopy, and X-Ray Powder Diffraction for Cu (II speciation in soil and mineral phases

    Directory of Open Access Journals (Sweden)

    Tatiana Minkina

    2017-04-01

    Full Text Available Interaction of Cu (II ions with the matrix of soil and mineral phases of layered silicates was assessed by the Miller method of selective sequential fractionation and a set of synchrotron X-ray methods, including X-ray powder diffraction (XRD and X-ray absorption spectroscopy (XANES. It was shown that the input of Cu into Calcic Chernozem in the form of monoxide (CuO and salt (Cu(NO32 affected the transformation of Cu compounds and their affinity for metal-bearing phases. It was found that the contamination of soil with a soluble Cu(II salt increased the bioavailability of the metal and the role of organic matter and Fe oxides in the fixation and retention of Cu. During the incubation of soil with Cu monoxide, the content of the metal in the residual fractions increased, which was related to the possible entry of Cu in the form of isomorphic impurities into silicates, as well as to the incomplete dissolution of exogenic compounds at the high level of their input into the soil. A mechanism for the structural transformation of minerals was revealed, which showed that ion exchange processes result in the sorption of Cu (II ions from the saturated solution by active sites on the internal surface of the lattice of dioctahedral aluminosilicates. Surface hydroxyls at the octahedral aluminum atom play the main role. X-ray diagnostics revealed that excess Cu(II ions are removed from the system due to the formation and precipitation of coarsely crystalline Cu(NO3(OH3.

  12. Cesium powder and pellets inner container decontamination method determination

    International Nuclear Information System (INIS)

    Ferrell, P.C.

    1998-01-01

    The cesium powder and pellets inner container is to be performance tested per the criteria specified in Section 4.0 of HNF-2399, ''Design, Fabrication, and Assembly Criteria for Cesium Powder and Pellet Inner Container.'' The test criteria specifies that the inner container be water tight during decontamination of the exterior surface. Three prototypes will be immersed into a pool of water to simulate a water decontamination process

  13. Effect of Sr substitution on superconductivity in Hg2(Ba1-ySry)2YCu2O8-d (part 1): a neutron powder diffraction study

    OpenAIRE

    Toulemonde, P.; Odier, P.; Bordet, P.; Floch, S. Le; Suard, E.

    2002-01-01

    The effect of Sr chemical pressure on superconductivity was investigated in Hg2(Ba1-ySry)2YCu2O8-d. The samples were synthesized at high pressure-high temperature from y = 0.0 to full substitution, y = 1.0. These Sr-substituted compounds are superconducting, without Ca doping on the Y site, and show an increasing Tc with Sr, reaching 42 K for y = 1.0. A detailed neutron powder diffraction study compares the structural changes induced by this chemical Sr/Ba substitution and the mechanical pres...

  14. Measurement of thickness of thin films by the X-ray diffraction method

    International Nuclear Information System (INIS)

    Srinivasan, C.; Balasingh, C.; Singh, A.K.

    1979-07-01

    X-ray diffraction method can be used to measure the thickness of thin films (coatings). The principle and the experimental details of the x-ray diffraction methods are described. The intensities of the diffracted beams are derived assuming a random orientation of the crystallites in the diffracting medium. Consequently, the expressions are not valid when the sample has preferred orientation. To check the performance of the method, thicknesses of nickel deposits on mild steel plates were determined by the x-ray diffraction method and the results compared with those obtained by the weighing method and metallographic examination. The weighing method which gives an accuracy of +- 0.1 micron is taken as the standard. The x-ray diffraction methods and the metallographic examinations give values within +- 1 micron of the value obtained by the weighing method. (author)

  15. Advances in data reduction of high-pressure x-ray powder diffraction data from two-dimensional detectors: a case study of schafarzikite (FeSb{sub 2}O{sub 4})

    Energy Technology Data Exchange (ETDEWEB)

    Hinrichsen, B [Max-Planck-Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart (Germany); Dinnebier, R E [Max-Planck-Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart (Germany); Rajiv, P [Max-Planck-Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart (Germany); Hanfland, M [European Synchrotron Radiation Facility, 6 rue Jules Horowitz, BP220, 38043 Grenoble Cedex (France); Grzechnik, A [Departamento de Fisica de la Materia Condensada, Facultad de Ciencia y Technologia, Universidad del Pais Vasco, Apartado 644, E-48080 Bilbao (Spain); Jansen, M [Max-Planck-Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart (Germany)

    2006-06-28

    Methods have been developed to facilitate the data analysis of multiple two-dimensional powder diffraction images. These include, among others, automatic detection and calibration of Debye-Scherrer ellipses using pattern recognition techniques, and signal filtering employing established statistical procedures like fractile statistics. All algorithms are implemented in the freely available program package Powder3D developed for the evaluation and graphical presentation of large powder diffraction data sets. As a case study, we report the pressure dependence of the crystal structure of iron antimony oxide FeSb{sub 2}O{sub 4} (p{<=}21 GPa, T = 298 K) using high-resolution angle dispersive x-ray powder diffraction. FeSb{sub 2}O{sub 4} shows two phase transitions in the measured pressure range. The crystal structures of all modifications consist of frameworks of Fe{sup 2+}O{sub 6} octahedra and irregular Sb{sup 3+}O{sub 4} polyhedra. At ambient conditions, FeSb{sub 2}O{sub 4} crystallizes in space group P4{sub 2}/mbc (phase I). Between p = 3.2 GPa and 4.1 GPa it exhibits a displacive second order phase transition to a structure of space group P 2{sub 1}/c (phase II, a = 5.7792(4) A, b = 8.3134(9) A, c = 8.4545(11) A, {beta} = 91.879(10){sup 0}, at p = 4.2 GPa). A second phase transition occurs between p = 6.4 GPa and 7.4 GPa to a structure of space group P4{sub 2}/m (phase III, a = 7.8498(4) A, c = 5.7452(5) A, at p = 10.5 GPa). A nonlinear compression behaviour over the entire pressure range is observed, which can be described by three Vinet equations in the ranges from p = 0.52 GPa to p 3.12 GPa, p = 4.2 GPa to p = 6.3 GPa and from p = 7.5 GPa to p = 19.8 GPa. The extrapolated bulk moduli of the high-pressure phases were determined to K{sub 0} = 49(2) GPa for phase I, K{sub 0} = 27(3) GPa for phase II and K{sub 0} = 45(2) GPa for phase III. The crystal structures of all phases are refined against x-ray powder data measured at several pressures between p = 0.52 GPa

  16. High Pressure X-Ray Diffraction Studies on Nanocrystalline Materials

    Science.gov (United States)

    Palosz, B.; Stelmakh, S.; Grzanka, E.; Gierlotka, S.; Pielaszek, R.; Bismayer, U.; Werner, S.; Palosz, W.

    2003-01-01

    Application of in situ high pressure powder diffraction technique for examination of specific structural properties of nanocrystals based on the experimental data of SiC nanocrystalline powders of 2 to 30 nrn diameter in diameter is presented. Limitations and capabilities of the experimental techniques themselves and methods of diffraction data elaboration applied to nanocrystals with very small dimensions (nanoparticles of different grain size.

  17. Spectroscopic studies, theoretical models and structural characterization. II. Synthesis and X-ray powder diffraction of the elpasolites Cs2NaSmCl6

    International Nuclear Information System (INIS)

    Poblete, V.; Acevedo, R.

    1998-01-01

    In this research work, we report the synthesis and structural characterization of the stoichiometric elpasolite Cs 2 NaSmCl 6 . The synthesis was performed under a solid state reaction in nitrogen atmosphere from the chemicals CsCl, NaCl and SmCl 3 weighted stoichiometrically. The best possible crystallization temperature was obtained using thermal studies of the type DTA/TGA (the thermal treatment was allowed to proceed for 2.5 hours at 755 Centigrade, showing a temperature gradient of 10 Centigrade/minute). The structural characterization by powder X-ray diffraction (XDR) indicates that this elpasolite belongs to the Fm 3m (O h 5 ) space group and the optimized structural parameters are as follows: a 0 = 10.8342 Armstrong, V 1271.72 Armstrong 3 , Z=4, M=651.88, D x =3.406 y D exp=3.41 ± 0.01. The profile refinement, using the Rietveld method, allowed us to fit the experimental and the calculated intensities of a total of 32 lines. The above result indicates that the condition R exp 2+ + 3Cl -1 and the counter ions filling the octahedral holes, in full agreement with anti fluorite type crystal. According to the above description, these elpasolite adopt the form (M 1/3 □ 2/3 ) 4 X 2 , where M labels the central metal, X stand for the chlorine ions and □ represent the vacancies, which may accommodate a significant amount of defects without collapsing. This experimental study provides the necessary input to test theoretical models against experimental data. (Author)

  18. An instrument for in situ time-resolved X-ray imaging and diffraction of laser powder bed fusion additive manufacturing processes

    Science.gov (United States)

    Calta, Nicholas P.; Wang, Jenny; Kiss, Andrew M.; Martin, Aiden A.; Depond, Philip J.; Guss, Gabriel M.; Thampy, Vivek; Fong, Anthony Y.; Weker, Johanna Nelson; Stone, Kevin H.; Tassone, Christopher J.; Kramer, Matthew J.; Toney, Michael F.; Van Buuren, Anthony; Matthews, Manyalibo J.

    2018-05-01

    In situ X-ray-based measurements of the laser powder bed fusion (LPBF) additive manufacturing process produce unique data for model validation and improved process understanding. Synchrotron X-ray imaging and diffraction provide high resolution, bulk sensitive information with sufficient sampling rates to probe melt pool dynamics as well as phase and microstructure evolution. Here, we describe a laboratory-scale LPBF test bed designed to accommodate diffraction and imaging experiments at a synchrotron X-ray source during LPBF operation. We also present experimental results using Ti-6Al-4V, a widely used aerospace alloy, as a model system. Both imaging and diffraction experiments were carried out at the Stanford Synchrotron Radiation Lightsource. Melt pool dynamics were imaged at frame rates up to 4 kHz with a ˜1.1 μm effective pixel size and revealed the formation of keyhole pores along the melt track due to vapor recoil forces. Diffraction experiments at sampling rates of 1 kHz captured phase evolution and lattice contraction during the rapid cooling present in LPBF within a ˜50 × 100 μm area. We also discuss the utility of these measurements for model validation and process improvement.

  19. Photocatalytic Activity in CH3CN Related to the Surface Properties of TiO2 Powders Prepared by Sol-Gel Method

    Directory of Open Access Journals (Sweden)

    Marta Bettoni

    2009-01-01

    Full Text Available Some TiO2 powders, prepared from titanium(IVtetraisopropoxide by the sol-gel method and thermally treated between 100 and 1000∘C, have been characterized by X-ray powder diffraction and by nitrogen adsorption and desorption at 77 K to calculate the BET-specific surface area, from which the micropore volume and the external surface area can be derived. The photocatalytic activity (ka of the above powders has been evaluated considering the TiO2-sensitized photo-oxidation of 4-methoxybenzyl alcohol in CH3CN as the test reaction. The decrease of ka have been related to the decrease of the BET surface area, the micropore volume, and the external surface area of the TiO2 powders, but a satisfactory linear correlation is observed only for the last superficial parameter.

  20. Synthesis of magnetite octahedrons from iron powders through a mild hydrothermal method

    International Nuclear Information System (INIS)

    Mao Baodong; Kang Zhenhui; Wang Enbo; Lian Suoyuan; Gao Lei; Tian Chungui; Wang Chunlei

    2006-01-01

    Magnetite (Fe 3 O 4 ) octahedral particles were fabricated from iron powders through a simple one-step alkali-assisted hydrothermal process. The crystallinity, morphology, and structural features of the as-prepared magnetite particles were investigated using powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). The values of saturation magnetization (M s ) and coercivity (H) of the magnetite octahedrons characterized on a vibrating sample magnetometer (VSM) are 89.81 emu/g and 70.6 Oe, respectively. The concentration of NaOH and the reaction temperature played a key role in the formation of the magnetite octahedrons

  1. Crystal structures of eight mono-methyl alkanes (C26–C32 via single-crystal and powder diffraction and DFT-D optimization

    Directory of Open Access Journals (Sweden)

    Lee Brooks

    2015-09-01

    Full Text Available The crystal structures of eight mono-methyl alkanes have been determined from single-crystal or high-resolution powder X-ray diffraction using synchrotron radiation. Mono-methyl alkanes can be found on the cuticles of insects and are believed to act as recognition pheromones in some social species, e.g. ants, wasps etc. The molecules were synthesized as pure S enantiomers and are (S-9-methylpentacosane, C26H54; (S-9-methylheptacosane and (S-11-methylheptacosane, C28H58; (S-7-methylnonacosane, (S-9-methylnonacosane, (S-11-methylnonacosane and (S-13-methylnonacosane, C30H62; and (S-9-methylhentriacontane, C32H66. All crystallize in space group P21. Depending on the position of the methyl group on the carbon chain, two packing schemes are observed, in which the molecules pack together hexagonally as linear rods with terminal and side methyl groups clustering to form distinct motifs. Carbon-chain torsion angles deviate by less than 10° from the fully extended conformation, but with one packing form showing greater curvature than the other near the position of the methyl side group. The crystal structures are optimized by dispersion-corrected DFT calculations, because of the difficulties in refining accurate structural parameters from powder diffraction data from relatively poorly crystalline materials.

  2. Conformational analysis of an acyclic tetrapeptide: ab-initio structure determination from X-ray powder diffraction, Hirshfeld surface analysis and electronic structure.

    Science.gov (United States)

    Das, Uday; Naskar, Jishu; Mukherjee, Alok Kumar

    2015-12-01

    A terminally protected acyclic tetrapeptide has been synthesized, and the crystal structure of its hydrated form, Boc-Tyr-Aib-Tyr-Ile-OMe·2H2O (1), has been determined directly from powder X-ray diffraction data. The backbone conformation of tetrapeptide (1) exhibiting two consecutive β-turns is stabilized by two 4 → 1 intramolecular N-H · · · O hydrogen bonds. In the crystalline state, the tetrapeptide molecules are assembled through water-mediated O-H · · · O hydrogen bonds to form two-dimensional molecular sheets, which are further linked by intermolecular C-H · · · O hydrogen bonds into a three-dimensional supramolecular framework. The molecular electrostatic potential (MEP) surface of (1) has been used to supplement the crystallographic observations. The nature of intermolecular interactions in (1) has been analyzed quantitatively through the Hirshfeld surface and two-dimensional fingerprint plot. The DFT optimized molecular geometry of (1) agrees closely with that obtained from the X-ray structure analysis. The present structure analysis of Boc-Tyr-Aib-Tyr-Ile-OMe·2H2 O (1) represents a case where ab-initio crystal structure of an acyclic tetrapeptide with considerable molecular flexibility has been accomplished from laboratory X-ray powder diffraction data. Copyright © 2015 European Peptide Society and John Wiley & Sons, Ltd.

  3. Structural study of CaMn_1_−_xMo_xO_3 (0.08 ≤ x ≤ 0.12) system by neutron powder diffraction

    International Nuclear Information System (INIS)

    Supelano, G.I.; Parra Vargas, C.A.; Barón-González, A.J.; Sarmiento Santos, A.; Frontera, C.

    2016-01-01

    Neutron powder diffraction experiments and magnetic measurements in polycrystalline CaMn_1_−_xMo_xO_3 (x = 0.08, 0.10, 0.12) point towards a possible charge and orbital order in this system. The analysis of structural and magnetic data show that the samples present structural phase transformation from Pnma to P2_1/m space group and the system has a C-type antiferromagnetic configuration at low temperature. A detailed analysis of the bond distances signals a small Jahn-Teller distortion of only one (x = 0.08) or of the two Mn ions (x = 0.10, 0.12). We identify the partially occupied e_g orbitals and this explains the C-type magnetic structure. - Highlights: • CaMn_1_−_xMo_xO_3 (x = 0.08, 0.10, 0.12) is investigated by neutron powder diffraction. • Analysis of individual Mn-O distances demonstrates the apparition of orbital order. • By symmetry analysis, we find that the low temperature magnetic structure is C-type. • Magnetic interactions foreseen by the orbital order explain the magnetic structure.

  4. A method of eliminating the surface defect in low-temperature oxidation powder added UO2 pellet

    International Nuclear Information System (INIS)

    Yoo, H. S.; Lee, S. J.; Kim, J. I.; Jeon, K. R.; Kim, J. W.

    2002-01-01

    A study on methods to eliminate surface defect shown in low-temperature oxidation powder added UO 2 pellet has been performed. Powders oxidized at 350 .deg. C for 4 hrs were prepared and mixed with UO 2 powder after crushing them. After being sintered, surfaces of the pellet were inspected both visually and optically. A large number of defects were observed on the surface of the specimens in which low-temperature oxidation powders were directly mixed or master mixed with UO 2 powder while both specimens produced from mixed powders including milled oxidation powders and powders that were milled totally after mixing had clean surfaces. However, optical examination showed considerably large defected pores in the milled oxidation powder added pellet and it was confirmed that the inner defects can be eliminated completely only when milling the entire mixture on UO 2 and low-temperature oxidation powder, but not by crushing only oxidation powder

  5. Crystal structure of aspartame anhydrate from powder diffraction data. Structural aspects of the dehydration process of aspartame

    NARCIS (Netherlands)

    Guguta, C.; Meekes, H.L.M.; Gelder, R. de

    2006-01-01

    Aspartame has three pseudo-polymorphic forms, two hydrates and a hemi-hydrate, for which crystal structures were determined from single-crystal diffraction data. This paper presents the crystal structure of the anhydrate, which was obtained by dehydrating the hemi-hydrate. The crystal structure of

  6. In situ synchrotron powder diffraction study of the setting reaction kinetics of magnesium-potassium phosphate cements

    Czech Academy of Sciences Publication Activity Database

    Viani, Alberto; Pérez-Estébanez, Marta; Pollastri, S.; Gualtieri, A. F.

    2016-01-01

    Roč. 79, January (2016), s. 344-352 ISSN 0008-8846 R&D Projects: GA MŠk(CZ) LO1219 Keywords : kinetics * reaction * X-ray diffraction * MgO * chemically bonded ceramics Subject RIV: JN - Civil Engineering Impact factor: 4.762, year: 2016 http://www.sciencedirect.com/science/article/pii/S0008884615002690

  7. Overlay improvement methods with diffraction based overlay and integrated metrology

    Science.gov (United States)

    Nam, Young-Sun; Kim, Sunny; Shin, Ju Hee; Choi, Young Sin; Yun, Sang Ho; Kim, Young Hoon; Shin, Si Woo; Kong, Jeong Heung; Kang, Young Seog; Ha, Hun Hwan

    2015-03-01

    To accord with new requirement of securing more overlay margin, not only the optical overlay measurement is faced with the technical limitations to represent cell pattern's behavior, but also the larger measurement samples are inevitable for minimizing statistical errors and better estimation of circumstance in a lot. From these reasons, diffraction based overlay (DBO) and integrated metrology (IM) were mainly proposed as new approaches for overlay enhancement in this paper.

  8. Structural and electrical properties of copper-nickel-aluminum alloys obtained by conventional powder metallurgy method

    International Nuclear Information System (INIS)

    Monteiro, Waldemar A.; Carrio, Juan A.G.; Silveira, C.R. da; Pertile, H.K.S.

    2009-01-01

    This work looked for to search out systematically, in scale of laboratory, copper-nickel-aluminum alloys (Cu-Ni-Al) with conventional powder metallurgy processing, in view of the maintenance of the electric and mechanical properties with the intention of getting electric connectors of high performance or high mechanical damping. After cold uniaxial pressing (1000 kPa), sintering (780 deg C) and convenient homogenization treatments (500 deg C for different times) under vacuum (powder metallurgy), the obtained Cu-Ni-Al alloys were characterized by optical microscopy, electrical conductivity, Vickers hardness. X rays powder diffraction data were collected for the sintered samples in order to a structural and microstructural analysis. The comparative analysis is based on the sintered density, hardness, macrostructures and microstructures of the samples. (author)

  9. Method of melting to solidify radioactive powder wastes

    International Nuclear Information System (INIS)

    Ootsuka, Katsuyuki; Miyazaki, Hitoshi.

    1981-01-01

    Purpose: To improve the microwave irradiation efficiency in a melting furnace. Constitution: Pelletization, sludgification and granularization are carried out as powderous dust reducing treatment. In the granularization, for example, radioactive burning ashes are sent from a hopper to a mixer and mixed with processing aids such as binders. Then, they are pelletized in a pelletizer into granular products and sent to a microwave melting furnace by way of a sieve screen. The granular products are melted by microwaves from a microwave guide tube and taken out through an exit. This can prevent powderous dusts from floating and scattering in the melting furnace and prevent the reduction in the microwave irradiation efficiency due to generation of electric discharges. (Seki, T.)

  10. Synthesis method for ultrananocrystalline diamond in powder employing a coaxial arc plasma gun

    Science.gov (United States)

    Naragino, Hiroshi; Tominaga, Aki; Hanada, Kenji; Yoshitake, Tsuyoshi

    2015-07-01

    A new method that enables us to synthesize ultrananocrystalline diamond (UNCD) in powder is proposed. Highly energetic carbon species ejected from a graphite cathode of a coaxial arc plasma gun were provided on a quartz plate at a high density by repeated arc discharge in a compact vacuum chamber, and resultant films automatically peeled from the plate were aggregated and powdered. The grain size was easily controlled from 2.4 to 15.0 nm by changing the arc discharge energy. It was experimentally demonstrated that the proposed method is a new and promising method that enables us to synthesize UNCD in powder easily and controllably.

  11. Synthesis method for ultrananocrystalline diamond in powder employing a coaxial arc plasma gun

    International Nuclear Information System (INIS)

    Naragino, Hiroshi; Tominaga, Aki; Yoshitake, Tsuyoshi; Hanada, Kenji

    2015-01-01

    A new method that enables us to synthesize ultrananocrystalline diamond (UNCD) in powder is proposed. Highly energetic carbon species ejected from a graphite cathode of a coaxial arc plasma gun were provided on a quartz plate at a high density by repeated arc discharge in a compact vacuum chamber, and resultant films automatically peeled from the plate were aggregated and powdered. The grain size was easily controlled from 2.4 to 15.0 nm by changing the arc discharge energy. It was experimentally demonstrated that the proposed method is a new and promising method that enables us to synthesize UNCD in powder easily and controllably. (author)

  12. New methods of X-ray diffraction spectrometry. II

    International Nuclear Information System (INIS)

    Soerum, H.; Bremer, J.

    1980-01-01

    The construction principles for a flexible X-ray spectrometer can be equipped either with a single curved crystal or with two curved crystals are described. A few of the theoretical 4+32 possible working modes are selected for a closer investigation and examples of recorded spectra are given. It is shown in the general single-crystal case that for a wavelength close to a cut-off energy the narrow diffraction cone has an elliptic section, as predicted by the theory. The spectrometer is discussed in terms of intensity, resolution and dispersive power. A comparison with other types of spectrometer is made. (Auth.)

  13. Measurement of residual stress in textured Al alloy by neutron diffraction method

    International Nuclear Information System (INIS)

    Okido, S.; Hayashi, M.; Tanaka, K.; Akiniwa, Y.; Minakawa, N.; Morii, Y.

    1999-01-01

    Residual stress generated in a shrunken aluminum alloy specimen, which was prepared for the round robin test conducted by VAMAS (Versailles Project on Advanced Materials and Standards) TWA-20 organized for the purpose of standardizing residual stress measurement methods, was evaluated by a neutron diffraction method. The main purpose of the round robin test was to assess the reproducibility of data obtained with the measurement facilities of the participants. The general standard of the Residual Stress Analyzer (RESA) constructed in the Japan Atomic Energy Research Institute was verified from the measured residual strains, which were equivalent to the values calculated by FEM and values measured by the research facilities in North America. Residual stress was calculated from residual strain in three perpendicular directions. The diffraction intensities were dependent on measurement directions since the prepared specimen possessed texture. Diffraction profiles in directions having a weak diffraction intensity caused an inaccurate evaluation of the residual stress. To solve this problem, a new method for evaluating residual stress with respect to diffraction plane dependency of the elastic constant was applied. The diffraction plane giving the highest intensity among 110, 200, and 220 diffraction was used to evaluate the residual strain in each of three directions. The residual strain obtained on the used diffraction plane was converted to the equivalent strain for the defined diffraction plane using the ratio of elastic constants of these two planes. The developed evaluation method achieved highly accurate measurement and remarkable efficiency in the measurement process. (author)

  14. Synthesis and characterization of scandia ceria stabilized zirconia powders prepared by polymeric precursor method for integration into anode-supported solid oxide fuel cells

    Science.gov (United States)

    Tu, Hengyong; Liu, Xin; Yu, Qingchun

    2011-03-01

    Scandia ceria stabilized zirconia (10Sc1CeSZ) powders are synthesized by polymeric precursor method for use as the electrolyte of anode-supported solid oxide fuel cell (SOFC). The synthesized powders are characterized in terms of crystalline structure, particle shape and size distribution by X-ray diffraction (XRD), transmission electron microscopy (TEM) and photon correlation spectroscopy (PCS). 10Sc1CeSZ electrolyte films are deposited on green anode substrate by screen-printing method. Effects of 10Sc1CeSZ powder characteristics on sintered films are investigated regarding the integration process for application as the electrolytes in anode-supported SOFCs. It is found that the 10Sc1CeSZ films made from nano-sized powders with average size of 655 nm are very porous with many open pores. In comparison, the 10Sc1CeSZ films made from micron-sized powders with average size of 2.5 μm, which are obtained by calcination of nano-sized powders at higher temperatures, are much denser with a few closed pinholes. The cell performances are 911 mW cm-2 at the current density of 1.25 A cm-2 and 800 °C by application of Ce0.8Gd0.2O2 (CGO) barrier layer and La0.6Sr0.4CoO3 (LSC) cathode.

  15. Temperature-Induced Desorption of Methyl tert-Butyl Ether Confined on ZSM-5: An In Situ Synchrotron XRD Powder Diffraction Study

    Directory of Open Access Journals (Sweden)

    Elisa Rodeghero

    2017-02-01

    Full Text Available The temperature-induced desorption of methyl tert-butyl ether (MTBE from aqueous solutions onto hydrophobic ZSM-5 was studied by in situ synchrotron powder diffraction and chromatographic techniques. This kind of information is crucial for designing and optimizing the regeneration treatment of such zeolite. The evolution of the structural features monitored by full profile Rietveld refinements revealed that a monoclinic (P21/n to orthorhombic (Pnma phase transition occurred at about 100 °C. The MTBE desorption process caused a remarkable change in the unit-cell parameters. Complete MTBE desorption was achieved upon heating at about 250 °C. Rietveld analysis demonstrated that the desorption process occurred without any significant zeolite crystallinity loss, but with slight deformations in the channel apertures.

  16. Order-disorder-reorder process in thermally treated dolomite samples: a combined powder and single-crystal X-ray diffraction study

    Science.gov (United States)

    Zucchini, A.; Comodi, P.; Katerinopoulou, A.; Balic-Zunic, T.; McCammon, C.; Frondini, F.

    2012-04-01

    A combined powder and single-crystal X-ray diffraction analysis of dolomite [CaMg(CO3)2] heated to 1,200°C at 3 GPa was made to study the order-disorder-reorder process. The order/disorder transition is inferred to start below 1,100°C, and complete disorder is attained at approximately 1,200°C. Twinned crystals characterized by high internal order were found in samples annealed over 1,100°C, and their fraction was found to increase with temperature. Evidences of twinning domains combined with probable remaining disordered portions of the structure imply that reordering processes occur during the quench. Twin domains are hereby proposed as a witness to thermally induced intra-layer-type cation disordering.

  17. Quadrupole lamp furnace for high temperature (up to 2050 K) synchrotron powder x-ray diffraction studies in air in reflection geometry

    International Nuclear Information System (INIS)

    Sarin, P.; Yoon, W.; Jurkschat, K.; Zschack, P.; Kriven, W. M.

    2006-01-01

    A four-lamp thermal image furnace has been developed to conduct high temperature x-ray diffraction in reflection geometry on oxide ceramic powder samples in air at temperatures ≤2050 K using synchrotron radiation. A refractory crucible made of Pt20%Rh alloy was used as a specimen holder. A material with well characterized lattice expansion properties was used as an internal crystallographic thermometer to determine the specimen temperature and displacement. The performance of the apparatus was verified by measurement of the thermal expansion properties of CeO 2 , MgO, and Pt which were found to be within ±3% of the acceptable values. The advantages, limitations, and important considerations of the instrument developed are discussed

  18. An In-situ method for the study of strain broadening usingsynchrotronx-ray diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Chiu C.; Lynch, Peter A.; Cheary, Robert W.; Clark, Simon M.

    2006-12-15

    A tensonometer for stretching metal foils has beenconstructed for the study of strain broadening in x-ray diffraction lineprofiles. This device, which is designed for use on the powderdiffractometer in Station 2.3 at Daresbury Laboratory, allows in-situmeasurements to be performed on samples under stress. It can be used fordata collection in either transmission or reflection modes using eithersymmetric or asymmetric diffraction geometries. As a test case,measurements were carried out on a 18mum thick copper foil experiencingstrain levels of up to 5 percent using both symmetric reflection andsymmetric transmission diffraction. All the diffraction profilesdisplayed peak broadening and asymmetry which increased with strain. Themeasured profiles were analysed by the fundamental parameters approachusing the TOPAS peak fitting software. All the observed broadenedprofiles were modelled by convoluting a refineable diffraction profile,representing the dislocation and crystallite size broadening, with afixed instrumental profile pre-determined usinghigh quality LaB6reference powder. The de-convolution process yielded "pure" sampleintegral breadths and asymmetry results which displayed a strongdependence on applied strain and increased almost linearly with appliedstrain. Assuming crystallite size broadening in combination withdislocation broadening arising from fcc a/2<110>111 dislocations,we have extracted the variation of mechanic al property with strain. Theobservation of both peak asymmetry and broadening has been interpreted asa manifestation of a cellular structure with cell walls and cellinteriors possessing high and low dislocation densities.

  19. Simple method of preparing nitrogen - doped nanosized TiO2 powders of high photocatalytic activity under visible light

    International Nuclear Information System (INIS)

    Nguyen Van Hung; Dang Thi Thanh Le

    2014-01-01

    Nitrogen-doped nanosized TiO 2 powders were prepared by a simple thermal treatment method of the mixture of titanium dioxide and urea. The prepared products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-Vis diffuse reflectance spectra (UV-Vis-DRS) and Fourier transform infrared (FT-IR) spectroscopy. The results showed that the crystal structure of N-TiO 2 was a mixture of anatase and rutile phases, and the average particle size was 31 nm calculated from XRD results. The UV-vis spectra indicate an increase in absorption of visible light when compared to undoped TiO 2 . The photocatalytic activity of nitrogen-doped TiO 2 powder was evaluated by the decomposition of methylene blue under visible light irradiation. And it was found that nitrogen-doped TiO 2 powders exhibited much higher photocatalytic activity than undoped TiO 2 . Moreover, the study also showed that, the doping N atoms improve the growth of the TiO 2 crystal and phase transformation. (author)

  20. Dehydrogenation kinetics of pure and nickel-doped magnesium hydride investigated by in situ time-resolved powder X-ray diffraction

    DEFF Research Database (Denmark)

    Jensen, T.R.; Andreasen, A.; Vegge, Tejs

    2006-01-01

    The dehydrogenation kinetics of pure and nickel (Ni)-doped (2w/w%) magnesium hydride (MgH2) have been investigated by in situ time-resolved powder X-ray diffraction (PXD). Deactivated samples, i.e. air exposed, are investigated in order to focus on the effect of magnesium oxide (MgO) surface layers......, which might be unavoidable for magnesium (Mg)-based storage media for mobile applications. A curved position-sensitive detector covering 120 degrees in 20 and a rotating anode X-ray source provide a time resolution of 45 s and up to 90 powder pattems collected during an experiment under isothermal...... by the Johnson-Mehi-Avrami formalism in order to derive rate constants at different temperatures. The apparent activation energies for dehydrogenation of pure and Ni-doped magnesium hydride were E-A approximate to 300 and 250 kJ/mol, respectively. Differential scanning calorimetry gave, E-A = 270 k...

  1. Resolution of the crystal structure of the deficient perovskite LaNiO2.5 from neutron powder diffraction data

    International Nuclear Information System (INIS)

    Alonso, J.A.; Martinez-Lope, M.J.

    1996-01-01

    The oxygen-deficient perovskite LaNiO 2.5 has been prepared by controlled reduction of LaNiO 3 with Zr metal. The XRD pattern could be indexed in a monoclinic unit-cell with dimensions a 0 xa 0 xa 0 (a 0 : lattice parameter of the ideal cubic perovskite). The indexing of the neutron powder diffraction pattern needed a doubled cell to account for the superstructure reflections originated by the oxygen vacancy ordering and the tilting of the Ni coordination polyhedra. The structure was solved and refined from the neutron powder data. The oxygen vacancies are ordered in such a way that square planar NiO 4 and NiO 6 octahedra alternate in the ab plane along the [110] direction. Both kinds of Ni polyhedra are fairly distorted and tilted in order to optimize the La-O distances, giving rise to a highly strained structure of metastable character. In fact, the compound readily takes oxygen, above 175 C in air, to give the much more stable LaNiO 3 perovskite. (orig.)

  2. Advanced x-ray stress analysis method for a single crystal using different diffraction plane families

    International Nuclear Information System (INIS)

    Imafuku, Muneyuki; Suzuki, Hiroshi; Sueyoshi, Kazuyuki; Akita, Koichi; Ohya, Shin-ichi

    2008-01-01

    Generalized formula of the x-ray stress analysis for a single crystal with unknown stress-free lattice parameter was proposed. This method enables us to evaluate the plane stress states with any combination of diffraction planes. We can choose and combine the appropriate x-ray sources and diffraction plane families, depending on the sample orientation and the apparatus, whenever diffraction condition is satisfied. The analysis of plane stress distributions in an iron single crystal was demonstrated combining with the diffraction data for Fe{211} and Fe{310} plane families

  3. COMPARING PARTICLE SIZE DISTRIBUTION ANALYSIS BY SEDIMENTATION AND LASER DIFFRACTION METHOD

    Directory of Open Access Journals (Sweden)

    Vito Ferro

    2009-06-01

    Full Text Available In this paper a brief review of the laser diffraction method is firstly carried out. Then, for 30 soil samples having a different texture classification sampled in Sicilian basin, a comparison between the two techniques is developed. The analysis demonstrated that the sand content measured by Sieve-Hydrometer method can be assumed equal to the one determinated by laser diffraction technique while an overestimation of the clay fraction measured by Sieve-Hydrometer method respect to laser diffraction technique was obtained. Finally a set of equations useful to refer LD measurements to SH method was proposed.

  4. Crystal structure relation between tetragonal and orthorhombic CsAlD{sub 4}: DFT and time-of-flight neutron powder diffraction studies

    Energy Technology Data Exchange (ETDEWEB)

    Bernert, Thomas; Krech, Daniel; Felderhoff, Michael; Weidenthaler, Claudia [Department of Heterogeneous Catalysis, Max-Planck-Institut fuer Kohlenforschung, Muelheim/Ruhr (Germany); Kockelmann, Winfried [Rutherford Appleton Laboratory, Harwell Oxford, Didcot (United Kingdom); Frankcombe, Terry J. [Research School of Chemistry, The Australian National University, Canberra, ACT (Australia); School of Physical, Environmental and Mathematic Sciences, The University of New South Wales, Canberra, ACT (Australia)

    2015-11-15

    The crystal structures of orthorhombic and tetragonal CsAlD{sub 4} were refined from time-of-flight neutron powder diffraction data starting from atomic positions predicted from DFT calculations. The earlier proposed crystal structure of orthorhombic CsAlH{sub 4} is confirmed. For tetragonal CsAlH{sub 4}, DFT calculations predicted a crystal structure in I4{sub 1}/amd as potential minimum structure, while from neutron diffraction studies of CsAlD{sub 4} best refinement is obtained for a disordered structure in the space group I4{sub 1}/a, with a = 5.67231(9) Aa, c = 14.2823(5) Aa. While the caesium atoms are located on the Wyckoff position 4b and aluminium at Wyckoff position 4a, there are two distinct deuterium positions at the Wyckoff position 16f with occupancies of 50 % each. From this structure, the previously reported phase transition between the orthorhombic and tetragonal polymorphs could be explained. (Copyright copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  5. Magnetic interactions in HoCr{sub 1-x}Fe{sub x}O{sub 3} (x = 0, 0.2) investigated by neutron powder diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xinzhi, E-mail: liuxinzhi1984.cn@163.com [Department of Nuclear Physics, China Institute of Atomic Energy, Beijing 102413 (China); Hao, Lijie; Ma, Xiaobai [Department of Nuclear Physics, China Institute of Atomic Energy, Beijing 102413 (China); Wang, Chin-Wei [Neutron Group, National Synchrotron Radiation Research Center, Hsinchu 30077, Taiwan (China); Klose, Frank [Australian Nuclear Science and Technology Organization, Lucas Heights, New South Wales 2234 (Australia); Department of Physics and Materials Science, The City University of Hong Kong, Hong Kong Special Administrative Region (Hong Kong); Liu, Yuntao, E-mail: ytliu@ciae.ac.cn [Department of Nuclear Physics, China Institute of Atomic Energy, Beijing 102413 (China); Sun, Kai; Li, Yuqing [Department of Nuclear Physics, China Institute of Atomic Energy, Beijing 102413 (China); Chen, Dongfeng, E-mail: dongfeng@ciae.ac.cn [Department of Nuclear Physics, China Institute of Atomic Energy, Beijing 102413 (China)

    2017-07-01

    Highlights: • The temperature dependent magnetism of HoCr{sub 1-x}Fe{sub x}O{sub 3} (x = 0, 0.2) were investigated by neutron diffraction. • Cr{sup 3+} moment follows a mean field theory while Ho{sup 3+} follows a spin 1/2 model. • An magneto-elastic strain was observed accompanying with the ordering of Cr{sup 3+}. - Abstract: The temperature dependent magnetism of Fe-doped rare earth orthochromite HoCr{sub 1-x}Fe{sub x}O{sub 3}(x = 0, 0.2) was investigated by neutron powder diffraction. It is found that the magnetism of Cr(Fe){sup 3+} can be well understood within mean field theory, while the ordering of Ho{sup 3+} was induced by the Cr(Fe){sup 3+} sublattice and can be satisfyingly described by an effective S = 1/2 model. The absences of both the most common G{sub x}F{sub z} configuration of Cr{sup 3+} and the ordering of Ho{sup 3+} caused by Ho-Ho interaction evidence a strong Ho{sup 3+}-Cr{sup 3+} interaction which dominates this system. On the other hand, a remarkable magnetoelastic strain was observed accompanying the Cr(Fe){sup 3+} ordering. An analysis based on the equation of state with a Grüneisen approximation was performed and revealed magnetic origin of this strain.

  6. Sizing of cracks by ultrasonic testing - Diffraction methods

    International Nuclear Information System (INIS)

    Hoegberg, K.; Sattari-Far, I.; Pers-Anderson, E.B.

    1989-01-01

    The work has been concentrated on manual ultrasonic testing of plates in carbon and austenitic steel with thicknesses of 10-40 mm. Evaluation of data was performed by studying the amplitude, accuracy (crack depth) and visibility. The experience from the project showed that identification of the weak signals from the crack tips requires well-trained personnel. Besides that, the following can be recommended: Estimate if the crack has compressive stresses. Especially shallow cracks are exposed for compressive stresses. Chose a refraction angle ≥ 60 degrees if the crack is deep. Try both low (approx equivalent to 2MHz) and high (approx equivalent to 4-5MHz) frequency. Lower frequencies often increase amplitude response. Avoid the combination of refraction angle greater than 60 degrees and low frequency. Inspect with half as well as full skip. Sometimes a stronger signal is received for full skip, because the amplitude of the diffracted signal is higher from the cracked side. Use complementary measurements with mode conversion techniques. Focused probes can improve the results, especially for complicated geometries. Do not use reference reflectors of EDM-notch type for verification of signal amplitude. No correlation between amplitude from an EDM-notch tip and a crack tip exists. Reference reflectors of EDM-notch type can be used to verify the resolution of the system. A shallow EDM-notch can show if the probe can separate the tip and corner. It is our experience that general solutions does not exist, and each case needs an individual solution

  7. Effect of drying method on the adsorption isotherms and isosteric heat of passion fruit pulp powder

    Directory of Open Access Journals (Sweden)

    Maria Angélica Marques Pedro

    2010-12-01

    Full Text Available The sorption behavior of dry products is generally affected by the drying method. The sorption isotherms are useful to determine and compare thermodynamic properties of passion fruit pulp powder processed by different drying methods. The objective of this study is to analyze the effects of different drying methods on the sorption properties of passion fruit pulp powder. Passion fruit pulp powder was dehydrated using different dryers: vacuum, spray dryer, vibro-fluidized, and freeze dryer. The moisture equilibrium data of Passion Fruit Pulp (PFP powders with 55% of maltodextrin (MD were determined at 20, 30, 40 and 50 ºC. The behavior of the curves was type III, according to Brunauer's classification, and the GAB model was fitted to the experimental equilibrium data. The equilibrium moisture contents of the samples were little affected by temperature variation. The spray dryer provides a dry product with higher adsorption capacity than that of the other methods. The vibro-fluidized bed drying showed higher adsorption capacity than that of vacuum and freeze drying. The vacuum and freeze drying presented the same adsorption capacity. The isosteric heats of sorption were found to decrease with increasing moisture content. Considering the effect of drying methods, the highest isosteric heat of sorption was observed for powders produced by spray drying, whereas powders obtained by vacuum and freeze drying showed the lowest isosteric heats of sorption.

  8. Preparation methods of U3O8 powder for MTR fuel elements

    International Nuclear Information System (INIS)

    Leal Neto, R.M.; Riella, H.G.

    1990-01-01

    Three preparation methods of U 3 O 8 powder have been studied with the aim of finding a simple and economic processing route: grinding of sintered U 3 O 8 pellets (Method-1); sintering of U 3 O 8 calcined granules (Method-2); and sintering of ammonium diuranate (ADU) granules (Method-3). Granulometric yield, powder characteristics and processing steps and difficulties have been taken into account for comparison purposes. Method-2 have been found to give the best results. Method-3 gives also good results, but there were some difficulties with ADU handling. (author) [pt

  9. COMPARING PARTICLE SIZE DISTRIBUTION ANALYSIS BY SEDIMENTATION AND LASER DIFFRACTION METHOD

    OpenAIRE

    Vito Ferro; Stefano Mirabile

    2009-01-01

    In this paper a brief review of the laser diffraction method is firstly carried out. Then, for 30 soil samples having a different texture classification sampled in Sicilian basin, a comparison between the two techniques is developed. The analysis demonstrated that the sand content measured by Sieve-Hydrometer method can be assumed equal to the one determinated by laser diffraction technique while an overestimation of the clay fraction measured by Sieve-Hydrometer method respect to laser diffr...

  10. A method for preparing a sintered glass powder for manufacturing microspheres

    International Nuclear Information System (INIS)

    Budrick, R.G.; King, F.T.; Nolen, R.L. Jr.; Solomon, D.E.

    1975-01-01

    The invention relates to the manufacture of sintered glass-powder. It relates to a method comprising the step of forming a vitreous gel so that it contains an occluded substance adapted to expand when heated, said gel being subsequently dried, then crushed and sorted prior to being washed and dried again. Application to the manufacture of sintered glass-powder for forming microspheres adapted to contain a thermonuclear fuel [fr

  11. Microstructural and electrical investigation of Cu-Ni-Cr alloys obtained by powder metallurgy method

    International Nuclear Information System (INIS)

    Carrio, Juan A.G.; Carvalhal, M.A.; Ayabe, L.M.; Monteiro, W.A.

    2009-01-01

    The aim of this work, using the powder metallurgy process, is to synthesize metallic alloys with high mechanical strength and high electric conductivity, after melting optimizing and thermal treatments. The Cu-Ni-Cr (wt%) alloys are characterized in their mechanical and electrical properties as well as the obtained microstructure. Through the process of powder metallurgy, contacts and structural parts can be obtained. The alloys elements are added to copper with the intention to improve their strength, ductility and thermal stability, without causing considerable damages in their form, electrical and thermal conductivity, and corrosion resistance. The metallic powders were mixed for a suitable time and then they were pressed in a cold uniaxial pressing (1000 kPa). Afterwards, the specimens were sintered in temperatures varying from 700 up to 800 deg C under vacuum. At last, the samples were homogenized at 550 deg C under vacuum, for special times. The comparative analysis is based on the sintered density, densification parameter, hardness, macrostructures and microstructures of the samples. The alloys were characterized by optical microscopy, X-rays powder diffraction, electrical conductivity and Vickers hardness. (author)

  12. Comparison of infrared laser beam shaping by diffractive and refractive methods

    CSIR Research Space (South Africa)

    Forbes, A

    2005-08-01

    Full Text Available Infra-red laser beam shaping has the inherent difficulty that simple ray tracing methods often yield anomalous results, due primarily to the propagation effects at longer wavelengths. Techniques based on diffraction theory have been developed...

  13. Quantitative method of X-ray diffraction phase analysis of building materials

    International Nuclear Information System (INIS)

    Czuba, J.; Dziedzic, A.

    1978-01-01

    Quantitative method of X-ray diffraction phase analysis of building materials, with use of internal standard, has been presented. The errors committed by determining the content of particular phases have been also given. (author)

  14. Method of making highly sinterable lanthanum chromite powder

    Science.gov (United States)

    Richards, Von L.; Singhal, Subhash C.

    1992-01-01

    A highly sinterable powder consisting essentially of LaCrO.sub.3, containing from 5 weight % to 20 weight % of a chromite of dopant Ca, Sr, Co, Ba, or Mg and a coating of a chromate of dopant Ca, Sr, Co, Ba, or Mg; is made by (1) forming a solution of La, Cr, and dopant; (2) heating their solutions; (3) forming a combined solution having a desired ratio of La, Cr, and dopant and heating to reduce solvent; (4) forming a foamed mass under vacuum; (5) burning off organic components and forming a charred material; (6) grinding the charred material; (7) heating the char at from 590.degree. C. to 950 C. in inert gas containing up to 50,000 ppm O.sub.2 to provide high specific surface area particles; (8) adding that material to a mixture of a nitrate of Cr and dopant to form a slurry; (9) grinding the particles in the slurry; (10) freeze or spray drying the slurry to provide a coating of nitrates on the particles; and (11) heating the coated particles to convert the nitrate coating to a chromate coating and provide a highly sinterable material having a high specific surface area of over 7 m.sup.2 /g.

  15. A novel method to produce dry geopolymer cement powder

    Directory of Open Access Journals (Sweden)

    H.A. Abdel-Gawwad

    2016-04-01

    Full Text Available Geopolymer cement is the result of reaction of two materials containing aluminosilicate and concentrated alkaline solution to produce an inorganic polymer binder. The alkali solutions are corrosive and often viscous solutions which are not user friendly, and would be difficult to use for bulk production. This work aims to produce one-mix geopolymer mixed water that could be an alternative to Portland cement by blending with dry activator. Sodium hydroxide (SH was dissolved in water and added to calcium carbonate (CC then dried at 80 °C for 8 h followed by pulverization to a fixed particle size to produce the dry activator consisting of calcium hydroxide (CH, sodium carbonate (SC and pirssonite (P. This increases their commercial availability. The dry activator was blended with granulated blast-furnace slag (GBFS to produce geopolymer cement powder and by addition of water; the geopolymerization process is started. The effect of W/C and SH/CC ratio on the physico-mechanical properties of slag pastes was studied. The results showed that the optimum percent of activator and CC content is 4% SH and 5% CC, by the weight of slag, which give the highest physico-mechanical properties of GBFS. The characterization of the activated slag pastes was carried out using TGA, DTG, IR spectroscopy and SEM techniques.

  16. New titrimetric method for oxygen to metal ratio in uranium oxide powders

    International Nuclear Information System (INIS)

    Ray, Vinod Kumar; Brahmananda Reddy, G.; Balaji Rao, Y.; Subba Rao, Y.

    2015-01-01

    O/U ratio is of high importance to both U 3 O 8 and UO 2 powders for different reasons. In UO 2 powder it is a guiding parameter for sintering process where as for U 3 O 8 , it indicates efficiency of ammonium di-uranate (ADU) to U 3 O 8 conversion process. In the present method for O/U determination, UO 2 and U 3 O 8 powders are dissolved in 4.5 M sulphuric acid and little HF by heating on hot plate. Subsequently, optimized quantity of phosphoric acid is added on cooling, for getting sharp end point. The resultant solution is titrated with standard potassium dichromate using barium diphenylamine sulphonate (BDS) as an indicator. The expanded uncertainties calculated for UO 2 and U 3 O 8 powders are ±0.004 and ±0.006 O/U ratio units respectively at 95 % confidence level. (author)

  17. Granulometric analysis of metallic oxide in ceramic powder form synthesized by different methods

    International Nuclear Information System (INIS)

    Neiva, L.S.; Simoes, A.N.; Simoes, V.N.; Bispo, A.; Gama, L.

    2012-01-01

    The aim of this work is to synthesize ceramic powders based on CuO/CeO 2 by means two different synthesis methods, they are: the combustion reaction method and Pechini method. It's part of the aim of this work subject all samples to a synthesized qualitative and quantitative chemical analysis, using the technique EDX and then to a granulometric analysis. The samples of the ceramic powder based on CuO/CeO 2 synthesized in this work by means of the two above synthesis methods, contain various concentrations of CuO ranging between 0 and 0.5 mol. According to the results, only the Pechini method of synthesis exerted a significant and defined influence on the capacity of particle unit agglomeration in these powders (author)

  18. Microstructural study of Ce1-xGdxO2-δ (x = 0.1 and 0.2) nano crystallized powders synthesized by the polymeric precursor method

    International Nuclear Information System (INIS)

    Cela, B.; Macedo, D.A.; Souza, G.L.; Paskocimas, C.A.; Martinelli, A.E.; Nascimento, R.M.

    2009-01-01

    Gadolinia-doped ceria powders (Ce 1-x Gd x O 2-δ ) were prepared with substitution of 10 and 20% of the dopant element by the polymeric precursor method. This method makes possible the attainment of homogeny powder in molecular level, ideal to application in Solid Oxide Fuel Cell (SOFC) component. In this work, the particulated materials were calcinated in a range from 500 °C to 900 °C and structurally characterized by X-Ray Diffraction (XRD). The sintering behaviors of the compact samples were determined by dilatometric analyses. The results showed the method efficiency to attain monophasic nanopowder with cubic crystalline structure starting at 700 °C. The crystallite average size and crystalline parameter were determined by the Rietveld refinement method. (author)

  19. Analysis of the diffraction pattern obtained by the Laue method

    International Nuclear Information System (INIS)

    Riquet, J. par; Bonnet, R.

    1978-01-01

    A computation method is presented which allows a rapid indexing of any unknown spot pattern obtained by back-reflection or transmission Laue methods. The Cartesian coordinates of n spots are measured in an orthonormal frame referred to the photographic film. Two spots 1 and 2 separated by a wide angular distance αsup(m) are carefully chosen. Their indices are assumed to be less than 5. The set (E) of all the pairs of planes (h 1 k 1 l 1 ) and (h 2 k 2 l 2 ) making an angle α close to αsup(m) is then computed. Since the pair of reflecting planes related to spots 1 and 2 belongs to (E), each computed pair of planes is tried, in order to determine the orientation of the crystal and to check whether the coordinates of the (n-2) other spots can be matched to dense planes of indices less than 8. If the uncertainty of the measurements is high or if n is too low, this method gives the possible orientations for the crystal. Plane indices less than 8 have been identified in cubic, tetragonal and orthorhombic crystals. (Auth.)

  20. Enhanced method of magnetic powder alignment for production of PLP Nd-Fe-B magnets

    Energy Technology Data Exchange (ETDEWEB)

    Popov, A.G. [M.N. Miheev Institute of Metal Physics of Ural Branch of Russian Academy of Sciences, Str. S. Kovalevskoy, 18, 620137 Ekaterinburg (Russian Federation); Institute of Natural Sciences and Mathematics, Ural Federal University, Av. Mira, 19, 620002 Ekaterinburg (Russian Federation); Golovnia, O.A., E-mail: golovnya@imp.uran.ru [M.N. Miheev Institute of Metal Physics of Ural Branch of Russian Academy of Sciences, Str. S. Kovalevskoy, 18, 620137 Ekaterinburg (Russian Federation); Institute of Natural Sciences and Mathematics, Ural Federal University, Av. Mira, 19, 620002 Ekaterinburg (Russian Federation); Protasov, A.V. [M.N. Miheev Institute of Metal Physics of Ural Branch of Russian Academy of Sciences, Str. S. Kovalevskoy, 18, 620137 Ekaterinburg (Russian Federation); Institute of Natural Sciences and Mathematics, Ural Federal University, Av. Mira, 19, 620002 Ekaterinburg (Russian Federation)

    2017-04-15

    It is demonstrated how the high degree of powder alignment in PLP magnets can be achieved by loading the powder into a container placed in a magnetic field of moderate strength. The strip-cast alloy with a composition of 30.00 Nd, 1.95 Dy, 66.42 Fe, 0.99 B, 0.54 Co, 0.1 Ga (wt%) was subjected to hydrogen decrepitation and then milled in a vibratory mill in toluene to an average particle size of 2.9 µm determined by the FSSS method. The powder was compacted in the magnetic field of 0.2 – 1.2 T to the filling density 2.6 – 3.2×10{sup 3} kg/m{sup 3}. It is shown that loading the powder into a container placed in a magnetic field enhances the degree of powder alignment in sintered Nd-Fe-B magnets produced from non-pressed powder. At the filling density less than 3.2×10{sup 3} kg/m{sup 3}, the density of magnets is high but insufficient, because of the formation of magnetostatic chains of particles, which impedes the powder compaction. The simulation by the discrete-element method qualitatively proves that the magnetostatic interaction of the chains of particles that are formed in the course of loading in the magnetic field stimulates a decrease in the density of the sintered magnets and its non-uniform distribution over the sample. As a result of the optimization of the parameters of the alignment and compaction of the powder loaded in a magnetic field, PLP magnets with B{sub r} ≥1.34 T, H{sub c} ≥950 kA/m, (BH){sub max} ≥340 kJ/m{sup 3}, and the degree of alignment exceeding 96% were produced. - Highlights: • The pressless process (PLP) in magnet production is studied. • A new method of the loading of powder in an applied DC magnetic field is suggested. • The method allows achieving higher degree of alignment in moderate magnetic field. • Density of sintered magnets is studied experimentally and via DEM simulation. • Low density is caused by the formation of magnetostatic chains of powder particles.

  1. Enhanced method of magnetic powder alignment for production of PLP Nd-Fe-B magnets

    International Nuclear Information System (INIS)

    Popov, A.G.; Golovnia, O.A.; Protasov, A.V.

    2017-01-01

    It is demonstrated how the high degree of powder alignment in PLP magnets can be achieved by loading the powder into a container placed in a magnetic field of moderate strength. The strip-cast alloy with a composition of 30.00 Nd, 1.95 Dy, 66.42 Fe, 0.99 B, 0.54 Co, 0.1 Ga (wt%) was subjected to hydrogen decrepitation and then milled in a vibratory mill in toluene to an average particle size of 2.9 µm determined by the FSSS method. The powder was compacted in the magnetic field of 0.2 – 1.2 T to the filling density 2.6 – 3.2×10 3 kg/m 3 . It is shown that loading the powder into a container placed in a magnetic field enhances the degree of powder alignment in sintered Nd-Fe-B magnets produced from non-pressed powder. At the filling density less than 3.2×10 3 kg/m 3 , the density of magnets is high but insufficient, because of the formation of magnetostatic chains of particles, which impedes the powder compaction. The simulation by the discrete-element method qualitatively proves that the magnetostatic interaction of the chains of particles that are formed in the course of loading in the magnetic field stimulates a decrease in the density of the sintered magnets and its non-uniform distribution over the sample. As a result of the optimization of the parameters of the alignment and compaction of the powder loaded in a magnetic field, PLP magnets with B r ≥1.34 T, H c ≥950 kA/m, (BH) max ≥340 kJ/m 3 , and the degree of alignment exceeding 96% were produced. - Highlights: • The pressless process (PLP) in magnet production is studied. • A new method of the loading of powder in an applied DC magnetic field is suggested. • The method allows achieving higher degree of alignment in moderate magnetic field. • Density of sintered magnets is studied experimentally and via DEM simulation. • Low density is caused by the formation of magnetostatic chains of powder particles.

  2. Preparation of cauliflower-like shaped Ba0.6Sr0.4TiO3 powders by modified oxalate co-precipitation method

    International Nuclear Information System (INIS)

    Li Mingli; Xu Mingxia

    2009-01-01

    The quantitative barium-strontium titanyl oxalate (Ba 0.6 Sr 0.4 TiO(C 2 O 4 ) 2 .4H 2 O, BSTO) precursor powders were prepared by the modified oxalate co-preparation method. It was based on the cation-exchange reaction between the stoichiometric solutions of oxalotitanic acid (H 2 TiO(C 2 O 4 ) 2 , HTO) and barium + strontium nitrate solution containing stoichiometric quantities of Ba and Sr ions. The pyrolysis of BSTO at 800 deg. C/4 h in air produced the homogeneous cauliflower-like shaped barium-strontium titanate (Ba 0.6 Sr 0.4 TiO 3 , BST) powders. The effect of polyethylene glycol (PEG) on morphology of BSTO and BST powders was also investigated. The characterization studies were carried on the as-dried BSTO and calcined BST powders by various physicochemical techniques, IR, X-ray diffraction (XRD), scanning electron microscopy (SEM), etc. The BSTO and BST powders obtained by aforementioned technique without PEG were homogeneous with spherical shape. The particles grew into spindle shape with the effect of PEG

  3. Neutron Powder Diffraction Measurements of the Spinel MgGa2O4:Cr3+ - A Comparative Study between the High Flux Diffractometer D2B at the ILL and the High Resolution Powder Diffractometer Aurora at IPEN

    International Nuclear Information System (INIS)

    Da Silva, M A F M; Sosman, L P; Yokaichiya, F; Henry, P F; Bordallo, H N; Mazzocchi, V L; Parente, C B R; Mestnik-Filho, J

    2012-01-01

    Optical materials that emit from the visible to the near-infrared spectral region are of great interest due to their possible application as tunable radiation sources, as signal transmission, display, optoelectronics signal storage, cellulose industry as well as in dosimetry. One important family of such systems are the spinel compounds doped with Cr 3+ , in which the physical the properties are related to the insertion of punctual defects in the crystalline structure. The purpose of our work is two fold. First, we compare the luminescence of the MgGa 2 O 4 -Ga 2 O 3 system with the single phase Ga 2 O 3 and MgGa 2 O 4 and relate structural changes observed in MgGa 2 O 4 -Ga 2 O 3 system to the optical properties, and secondly, to compare the neutron powder diffraction results obtained using two diffractometers: D2B located at the ILL (Grenoble, France) and Aurora located at IPEN (São Paulo, Brazil). In the configuration chosen, Aurora shows an improved resolution, which is related to the design of its silicon focusing monochromator.

  4. Evaluation of ring shear testing as a characterization method for powder flow in small-scale powder processing equipment

    DEFF Research Database (Denmark)

    Søgaard, Søren Vinter; Pedersen, Troels; Allesø, Morten

    2014-01-01

    Powder flow in small-scale equipment is challenging to predict. To meet this need, the impact of consolidation during powder flow characterization, the level of consolidation existing during discharge of powders from a tablet press hopper and the uncertainty of shear and wall friction measurements...... normal stress were approximately 200Pa and 114Pa, respectively, in the critical transition from the converging to the lower vertical section of the hopper. The lower limit of consolidation for the shear and wall friction test was approximately 500Pa and 200Pa, respectively. At this consolidation level......, the wall and shear stress resolution influences the precision of the measured powder flow properties. This study highlights the need for an improved experimental setup which would be capable of measuring the flow properties of powders under very small consolidation stresses with a high shear stress...

  5. On the evaluation of X-ray diffraction experiments by the regularization method

    Energy Technology Data Exchange (ETDEWEB)

    Trubin, V.A.; Szasz, A. (Lab. of Surface and Interface Physics, Eoetvoes Univ., Budapest (Hungary))

    1991-05-16

    The characteristic property of diffractometers as the presence of occasional and systematic errors in measured patterns requires such an evaluation which is as informative as possible. This circumstance gives rise to the problem of optimal planning of the experiment. The X-ray diffraction optimization problem with application of the regularization method is studied. The proposal permits to determine more accurately the unknown true characteristics of the X-ray diffraction experiment. (orig.).

  6. On the evaluation of X-ray diffraction experiments by the regularization method

    International Nuclear Information System (INIS)

    Trubin, V.A.; Szasz, A.

    1991-01-01

    The characteristic property of diffractometers as the presence of occasional and systematic errors in measured patterns requires such an evaluation which is as informative as possible. This circumstance gives rise to the problem of optimal planning of the experiment. The X-ray diffraction optimization problem with application of the regularization method is studied. The proposal permits to determine more accurately the unknown true characteristics of the X-ray diffraction experiment. (orig.)

  7. Influence of Ba/Fe mole ratios on magnetic properties, crystallite size and shifting of X-ray diffraction peaks of nanocrystalline BaFe12O19 powder, prepared by sol gel auto combu

    Science.gov (United States)

    Suastiyanti, Dwita; Sudarmaji, Arif; Soegijono, Bambang

    2012-06-01

    Barium hexaferrite BaFe12O19 (BFO) is of great importance as permanent magnets, particularly for magnetic recording as well as in microwave devices. Nano-crystalline BFO powders were prepared by sol gel auto combustion method in citric acid - metal nitrates system. Hence the mole ratios of Ba/Fe were variated at 1:12; 1:11.5 and 1:11. Ratio of cation to fuel was fixed at 1:1. An appropriate amount of amonia solution was added dropwise to this solution with constant stirring until the PH reached 7 in all cases. Heating at 850oC for 10 hours for each sample to get final formation of BFO nanocrystalline. The data from XRD showing the lattice parameters a,c and the unit-cell volume V, confirm that BFO with ratio 1:12 has same crystall parameters with ratio 1:11. Ratio of Ba/Fe 1:12 and 1:11 have diffraction pattern similarly at almost each 2 θ for each samples. Ratio of Ba/Fe 1: 11.5 has the finest crystallite size 22 nm. Almost diffraction pattern peaks of Ba/Fe 1:11.5 move to the left from of Ba/Fe 1:12 then return to diffraction pattern of Ba/Fe 1:12 for Ba/Fe 1:11. SEM observations show the particle size less than 100 nm and the same shape for each sample. Ratio of Ba/Fe 1: 12 gives the highest intrinsic coercive Hc = 427.3 kA/m. The highest remanent magnetization is at ratio 1:11 with Mr = 0.170 T. BFO with mole ratio 1:11.5 has the finest grain 22 nm, good magnetic properties and the highest value of best FoM 89%.

  8. Magnetic and electronic properties of RNiO{sub 3} (R = Pr, Nd, Eu, Ho and Y) perovskites studied by resonant soft x-ray magnetic powder diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Bodenthin, Y; Staub, U; Piamonteze, C; Garcia-Fernandez, M [Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); Martinez-Lope, M J; Alonso, J A, E-mail: urs.staub@psi.ch [Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, E-28049 Madrid (Spain)

    2011-01-26

    Soft x-ray resonant magnetic powder diffraction of the (1/2 0 1/2) reflection at the Ni L{sub 2,3} edges is used to study the magnetic and electronic properties of a series of RNiO{sub 3} materials (with R = Pr, Nd, Eu, Ho and Y) below the metal-insulator transition. The polarization and energy dependence of the reflection gives further support for a non-collinear magnetic structure and charge disproportionation in the whole RNiO{sub 3} series. Only small changes in the spectra of the magnetic (1/2 0 1/2) reflection and in the absorption spectra could be detected. The results are discussed with comparison to charge transfer multiplet calculations. Our results emphasize that the lighter and heavier RNiO{sub 3} compounds are very similar from the point of view of their local electronic and magnetic state despite the strong change of the metal-to-insulator transition temperature.

  9. The structural phase diagram and oxygen equilibrium partial pressure of YBa 2Cu 3O 6+ x studied by neutron powder diffraction and gas volumetry

    Science.gov (United States)

    Andersen, N. H.; Lebech, B.; Poulsen, H. F.

    1990-12-01

    An experimental technique based on neutron powder diffraction and gas volumetry is presented and used to study the structural phase diagram of YBa 2Cu 3O 6+ x under equilibrium conditions in an extended part of ( x, T)-phase (0.15< x<0.92 and 25° C< T<725°C). Our experimental observations lend strong support to a recent two-dimensional anisotropic next-nearest-neighbour Ising model calculation (the ASYNNNI model) of the basal plane oxygen ordering based of first principle interaction parameters. Simultaneous measurements of the oxygen equilibrium partial pressure show anomalies, one of which proves the thermodynamic stability of the orthorhombic OII double cell structure. Striking similarity with predictions of recent model calculations support that another anomaly may be interpreted to result from local one-dimensional fluctuations in the distribution of oxygen atoms in the basal plane of tetragonal YBCO. Our pressure data also indicate that x=0.92 is a maximum obtainable oxygen concentration for oxygen pressures below 760 Torr.

  10. Twin-domain size and bulk oxygen in-diffusion kinetics of YBa 2Cu 3O 6+x studied by neutron powder diffraction and gas volumetry

    Science.gov (United States)

    Poulsen, H. F.; Andersen, N. H.; Lebech, B.

    1991-02-01

    We report experimental results of twin-domain size and bulk oxygen in-diffusion kinetics of YBa 2Cu 3O 6+ x, which supplement a previous and simultaneous study of the structural phase diagram and oxygen equilibrium partial pressure. Analysis of neutron powder diffraction peak broadening show features which are identified to result from temperature independent twin-domain formation in to different orthorhombic phases with domain sizes and 250 and 350Å, respectively. The oxygen in-diffusion flow shows simple relaxation type behaviour J=J 0 exp( {-t}/{τ}) despite a rather broad particle size distribution. At higher temperatures, τ is activated with activation energies 0.55 and 0.25 eV in the tetragonal and orthorhombic phases, respectively. Comparison between twin-domain sizes and bulk oxygen in-diffusion time constants indicates that the twin-domain boundaries may contribute to the effective bulk oxygen in-diffusion. All our results may be interpreted in terms of the 2D ASYNNNI model description of the oxygen basal plane ordering, and they suggest that recent first principles interaction parameters should be modified.

  11. Stacking Faults and Polytypes for Layered Double Hydroxides: What Can We Learn from Simulated and Experimental X-ray Powder Diffraction Data?

    Science.gov (United States)

    Sławiński, Wojciech A; Sjåstad, Anja Olafsen; Fjellvåg, Helmer

    2016-12-19

    Layered double hydroxides (LDH) are a broad group of widely studied materials. The layered character of those materials and their high flexibility for accommodating different metals and anions make them technologically interesting. The general formula for the LDH compound is [M 1-x II M x III (OH) 2 ][A n- ] x/n ·mH 2 O, where M II is a divalent metal cation which can be substituted by M III trivalent cation, and A n- is a charge compensating anion located between positively charged layers. In this paper we present a comprehensive study on possible structural disorder in LDH. We show how X-ray powder diffraction (XRPD) can be used to reveal important features of the LDH crystal structure such as stacking faults, random interlayer shifts, anion-molecule orientation, crystal water content, distribution of interlayer distances, and also LDH slab thickness. All calculations were performed using the Discus package, which gives a better flexibility in defining stacking fault sequences, simulating and refining XRPD patterns, relative to DIFFaX, DIFFaX+, and FAULTS. Finally, we show how the modeling can be applied to two LDH samples: Ni 0.67 Cr 0.33 (OH) 2 (CO 3 ) 0.16 ·mH 2 O (3D structure) and Mg 0.67 Al 0.33 (OH) 2 (NO 3 ) 0.33 (2D layered structure).

  12. Reflection and diffraction of atomic de Broglie waves by evanescent laser waves. Bare-state method

    International Nuclear Information System (INIS)

    Feng, Xiaoping; Witte, N.S.; Hollenberg, C.L.; Opat, G.

    1994-01-01

    Two methods are presented for the investigation of the reflection and diffraction of atoms by gratings formed either by standing or travelling evanescent laser waves. Both methods use the bare-state rather than dressed-state picture. One method is based on the Born series, whereas the other is based on the Laplace transformation of the coupled differential equations. The two methods yield the same theoretical expressions for the reflected and diffracted atomic waves in the whole space including the interaction and the asymptotic regions. 1 ref., 1 fig

  13. Development of an ellipse fitting method with which to analyse selected area electron diffraction patterns

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, D.R.G., E-mail: dmitchel@uow.edu.au [Electron Microscopy Centre, Australian Institute for Innovative Materials, Innovation Campus, University of Wollongong, North Wollongong, NSW 2500 (Australia); Van den Berg, J.A. [Electron Microscopy Centre, Australian Institute for Innovative Materials, Innovation Campus, University of Wollongong, North Wollongong, NSW 2500 (Australia); Catalyst Fundamentals, Fischer-Tropsch and Syngas Conversion Research, Sasol Technology R & D, Sasolburg 1947 (South Africa)

    2016-01-15

    A software method has been developed which uses ellipse fitting to analyse electron diffraction patterns from polycrystalline materials. The method, which requires minimal user input, can determine the pattern centre and the diameter of diffraction rings with sub-pixel precision. This enables accurate crystallographic information to be obtained in a rapid and consistent manner. Since the method fits ellipses, it can detect, quantify and correct any elliptical distortion introduced by the imaging system. Distortion information derived from polycrystalline patterns as a function of camera length can be subsequently recalled and applied to single crystal patterns, resulting in improved precision and accuracy. The method has been implemented as a plugin for the DigitalMicrograph software by Gatan, and is a freely available via the internet. - Highlights: • A robust ellipse fitting method is developed. • Freely available software for automated diffraction pattern analysis is demonstrated. • Measurement and correction of elliptical distortion is routinely achieved.

  14. Method development and validation for measuring the particle size distribution of pentaerythritol tetranitrate (PETN) powders.

    Energy Technology Data Exchange (ETDEWEB)

    Young, Sharissa Gay

    2005-09-01

    Currently, the critical particle properties of pentaerythritol tetranitrate (PETN) that influence deflagration-to-detonation time in exploding bridge wire detonators (EBW) are not known in sufficient detail to allow development of a predictive failure model. The specific surface area (SSA) of many PETN powders has been measured using both permeametry and gas absorption methods and has been found to have a critical effect on EBW detonator performance. The permeametry measure of SSA is a function of particle shape, packed bed pore geometry, and particle size distribution (PSD). Yet there is a general lack of agreement in PSD measurements between laboratories, raising concerns regarding collaboration and complicating efforts to understand changes in EBW performance related to powder properties. Benchmarking of data between laboratories that routinely perform detailed PSD characterization of powder samples and the determination of the most appropriate method to measure each PETN powder are necessary to discern correlations between performance and powder properties and to collaborate with partnering laboratories. To this end, a comparison was made of the PSD measured by three laboratories using their own standard procedures for light scattering instruments. Three PETN powder samples with different surface areas and particle morphologies were characterized. Differences in bulk PSD data generated by each laboratory were found to result from variations in sonication of the samples during preparation. The effect of this sonication was found to depend on particle morphology of the PETN samples, being deleterious to some PETN samples and advantageous for others in moderation. Discrepancies in the submicron-sized particle characterization data were related to an instrument-specific artifact particular to one laboratory. The type of carrier fluid used by each laboratory to suspend the PETN particles for the light scattering measurement had no consistent effect on the resulting

  15. Diffractometric method for obtaining of x-ray diffraction patterns of transplutonium element compounds

    International Nuclear Information System (INIS)

    Dubasov, Yu.V.; Aleksandrov, B.M.; Baranov, Yu.I.; Golubev, V.A.; Nikolaev, V.B.

    1986-01-01

    Method allowing to carry out X-ray radiographic investigations of powders of high radioactive α-sources (transuranium and transplutonium compounds) by the diffractometric method have been developed. The method is tested for three americium compounds crystallizing in different syngonies - dioxide, formiate, oxalate. The substance quantity necessary for analysis is 0.5-1 mg. The investigations can be carried out with diffractometers of general purpose of DRON-UMI and DRON-20 types

  16. Ray tracing method for simulation of laser beam interaction with random packings of powders

    Science.gov (United States)

    Kovalev, O. B.; Kovaleva, I. O.; Belyaev, V. V.

    2018-03-01

    Selective laser sintering is a technology of rapid manufacturing of a free form that is created as a solid object by selectively fusing successive layers of powder using a laser. The motivation of this study is due to the currently insufficient understanding of the processes and phenomena of selective laser melting of powders whose time scales differ by orders of magnitude. To construct random packings from mono- and polydispersed solid spheres, the algorithm of their generation based on the discrete element method is used. A numerical method of ray tracing is proposed that is used to simulate the interaction of laser radiation with a random bulk packing of spherical particles and to predict the optical properties of the granular layer, the extinction and absorption coefficients, depending on the optical properties of a powder material.

  17. Crystallographic orientation study of silicon steels using X-ray diffraction, electrons diffraction and the Etch Pit method

    International Nuclear Information System (INIS)

    Santos, Hamilta de Oliveira

    1999-01-01

    The aim of the present study is the microstructural and crystallographic orientation of Fe-3%Si steel. The silicon steel shows good electrical properties and it is used in the nuclear and electrical power fields. The studied steel was supplied by Cia. Acos Especiais Itabira S/A - ACESITA. The material was received in the hot compressed condition, in one or two passes. The hot compressing temperatures used were 900, 1000 and 1100 deg C with soaking times ranging from 32 to 470 s. The material preferential crystallographic orientation was evaluated in every grain of the samples. The characterization techniques used were: scanning electron microscopy (SEM) using the etch pit method; X ray diffraction using the Laue back-reflection method; orientation imaging microscopy (OIM). Microstructural characterization in terms of grain size measurement and mean number of grains in the sample were also undertaken. The Laue method was found an easy technique to access crystallographic orientation of this work polycrystalline samples 2.5 mm average grain size. This was due to the inability to focus the X-rays on a single grain of the material. The scanning electron microscopy showed microcavities left by the etch pit method, which allowed the observation of the crystallographic orientation of each grain from the samples. No conclusive grain crystallographic orientation was possible to obtain by the OIM technique due to the non-existing rolling direction. A more extensive work with the OIM technique must be undertaken on the Fe-3%Si with oriented grains and non oriented grains. (author)

  18. Method for fluoride ion depletion of UO2 powders

    International Nuclear Information System (INIS)

    Beutner, R.; Ploeger, F.

    1978-01-01

    The method described consists in removing the hydrogen still present from the reduction during the preparation of UO 2 as completely as possible and in performing a pyrohydrolysis at temperatures above 650 0 C for at least 45 minutes. The removal of fluorine is necessary in order to avoid cladding tube damaging. (UA) [de

  19. Preparation, spectral, X-ray powder diffraction and computational studies and genotoxic properties of new azo-azomethine metal chelates

    Science.gov (United States)

    Bitmez, Şirin; Sayin, Koray; Avar, Bariş; Köse, Muhammet; Kayraldız, Ahmet; Kurtoğlu, Mükerrem

    2014-11-01

    A new tridentate azo-azomethine ligand, N‧-[{2-hydroxy-5-[(4-nitrophenyl)diazenyl]phenyl}methylidene]benzohydrazidemonohydrate, (sbH·H2O) (1), is prepared by condensation of benzohydrazide and 2-hydroxy-5-[(4-nitrophenyl)diazenyl]benzaldehyde (a) with treatment of a solution of diazonium salt of p-nitroaniline and 2-hydroxybenzaldehyde in EtOH. The five coordination compounds, [Co(sb)2]·4H2O (2), [Ni(sb)2]·H2O (3), [Cu(sb)2]·4H2O (4), [Zn(sb)2]·H2O (5) and [Cd(sb)2]·H2O (6) are prepared by reacting the Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) ions with the ligand. The structures of the compounds are elucidated from the elemental analyses data and spectroscopic studies. It is found the ligand acts as a tridentate bending through phenolic and carbonyl oxygens and nitrogen atom of the Cdbnd Nsbnd group similar to the most of salicylaldimines. Comparison of the infrared spectra of the ligand and its metal complexes confirm that azo-Schiff base behaves as a monobasic tridentate ligand towards the central metal ion with an ONO donor sequence. Upon complexation with the ligand, the Cd(II), and Zn(II) ions form monoclinic structures, while Co(II), Cu(II) and Ni(II) ions form orthorhombic structures. Quantum chemical calculations are performed on tautomers and its metal chelates by using DFT/B3LYP method. Most stable tautomer is determined as tautomer (1a). The geometrical parameters of its metal chelates are obtained as theoretically. The NLO properties of tautomer (1a) and its metal complexes are investigated. Finally, the ligand and its metal complexes are assessed for their genotoxicity.

  20. Synthesis of ceramic powder of TiO_2 doped with Zr by the Pechini Method applied in ceramic membranes for water treatment

    International Nuclear Information System (INIS)

    Farias, R.F.V.; Fernandes, M.S.M.; Silva, R.S.; Franca, K.B.; Lira, H.L.; Bonifacio, M.A.R.

    2016-01-01

    This paper describes the synthesis of ceramic powder of TiO2 doped with Zr by the polymeric precursor method, also known as Pechini method applied in ceramic membranes for water treatment. Three compositions were synthesized according to the molar ratio Ti_x-1Zr_xO_2 (x = 0.25, 0.50 and 0.75 moles), calcined at 700° C/1h. The samples were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM) and microbiological analysis. The presence of the doping element was not decisive in the average size of crystallite, which ranged from 5.5 to 11.3 nm. The SEM images showed clusters with uniform surface and granular aspect, it is still possible to see a clearly porous structure formed by clusters of uniform size for all samples. The microbiological analyses of powders have revealed that they have bactericidal properties. (author)

  1. Method for producing dysprosium-iron-boron alloy powder

    International Nuclear Information System (INIS)

    Camp, F.E.; Wooden, S.A.

    1989-01-01

    A method for producing a dysprosium-iron alloy adapted for use in the manufacture of rare-earth element containing, iron-boron permanent magnets, the method including providing a particle mixture comprising dysprosium oxide, iron and calcium, compacting the particle mixture to produce a consolidated article, heating the article for a time at temperature to form a metallic compound comprising dysprosium and iron and to form calcium oxide, producing a particle mass of -35 mesh from the compact, washing the particle mass with water at a temperature no greater than 10 0 C to react to the calcium and to the calcium oxide therewith to form a calcium hydroxide, while preventing oxidation of the particle mass, and removing the calcium hydroxide from the particle mass

  2. Superhydrophobic transparent films from silica powder: Comparison of fabrication methods

    KAUST Repository

    Liu, Li-Der; Lin, Chao-Sung; Tikekar, Mukul; Chen, Ping-Hei

    2011-01-01

    The lotus leaf is known for its self-clean, superhydrophobic surface, which displays a hierarchical structure covered with a thin wax-like material. In this study, three fabrication techniques, using silicon dioxide particles to create surface roughness followed by a surface modification with a film of polydimethylsiloxane, were applied on a transparent glass substrate. The fabrication techniques differed mainly on the deposition of silicon dioxide particles, which included organic, inorganic, and physical methods. Each technique was used to coat three samples of varying particle load. The surface of each sample was evaluated with contact angle goniometer and optical spectrometer. Results confirmed the inverse relationships between contact angle and optical transmissivity independent of fabrication techniques. Microstructural morphologies also suggested the advantage of physical deposition over chemical methods. In summary, the direct sintering method proved outstanding for its contact angle vs transmissivity efficiency, and capable of generating a contact angle as high as 174°. © 2011 Elsevier B.V. All rights reserved.

  3. Method for continuous synthesis of metal oxide powders

    Science.gov (United States)

    Berry, David A.; Haynes, Daniel J.; Shekhawat, Dushyant; Smith, Mark W.

    2015-09-08

    A method for the rapid and continuous production of crystalline mixed-metal oxides from a precursor solution comprised of a polymerizing agent, chelated metal ions, and a solvent. The method discharges solution droplets of less than 500 .mu.m diameter using an atomizing or spray-type process into a reactor having multiple temperature zones. Rapid evaporation occurs in a first zone, followed by mixed-metal organic foam formation in a second zone, followed by amorphous and partially crystalline oxide precursor formation in a third zone, followed by formation of the substantially crystalline mixed-metal oxide in a fourth zone. The method operates in a continuous rather than batch manner and the use of small droplets as the starting material for the temperature-based process allows relatively high temperature processing. In a particular embodiment, the first zone operates at 100-300.degree. C., the second zone operates at 300-700.degree. C., and the third operates at 700-1000.degree. C., and fourth zone operates at at least 700.degree. C. The resulting crystalline mixed-metal oxides display a high degree of crystallinity and sphericity with typical diameters on the order of 50 .mu.m or less.

  4. Superhydrophobic transparent films from silica powder: Comparison of fabrication methods

    KAUST Repository

    Liu, Li-Der

    2011-07-01

    The lotus leaf is known for its self-clean, superhydrophobic surface, which displays a hierarchical structure covered with a thin wax-like material. In this study, three fabrication techniques, using silicon dioxide particles to create surface roughness followed by a surface modification with a film of polydimethylsiloxane, were applied on a transparent glass substrate. The fabrication techniques differed mainly on the deposition of silicon dioxide particles, which included organic, inorganic, and physical methods. Each technique was used to coat three samples of varying particle load. The surface of each sample was evaluated with contact angle goniometer and optical spectrometer. Results confirmed the inverse relationships between contact angle and optical transmissivity independent of fabrication techniques. Microstructural morphologies also suggested the advantage of physical deposition over chemical methods. In summary, the direct sintering method proved outstanding for its contact angle vs transmissivity efficiency, and capable of generating a contact angle as high as 174°. © 2011 Elsevier B.V. All rights reserved.

  5. Consumer acceptance and aroma characterization of navy bean (Phaseolus vulgaris) powders prepared by extrusion and conventional processing methods.

    Science.gov (United States)

    Szczygiel, Edward J; Harte, Janice B; Strasburg, Gale M; Cho, Sungeun

    2017-09-01

    Food products produced with bean ingredients are gaining in popularity among consumers due to the reported health benefits. Navy bean (Phaseolus vulgaris) powder produced through extrusion can be considered as a resource-efficient alternative to conventional methods, which often involve high water inputs. Therefore, navy bean powders produced with extrusion and conventional methods were assessed for the impact of processing on consumer liking in end-use products and odor-active compounds. Consumer acceptance results reveal significant differences in flavor, texture and overall acceptance scores of several products produced with navy bean powder. Crackers produced with extruded navy bean powder received higher hedonic flavor ratings than those produced with commercial navy bean powder (P < 0.001). GC-O data showed that the commercial powder produced through conventional processing had much greater contents of several aliphatic aldehydes commonly formed via lipid oxidation, such as hexanal, octanal and nonanal with descriptors of 'grassy', 'nutty', 'fruity', 'dusty', and 'cleaner', compared to the extruded powder. Extrusion processed navy bean powders were preferred over commercial powders for certain navy bean powder applications. This is best explained by substantial differences in aroma profiles of the two powders that may have been caused by lipid oxidation. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  6. Preparation of High-Grade Powders from Tomato Paste Using a Vacuum Foam Drying Method.

    Science.gov (United States)

    Sramek, Martin; Schweiggert, Ralf Martin; van Kampen, Andreas; Carle, Reinhold; Kohlus, Reinhard

    2015-08-01

    We present a rapid and gentle drying method for the production of high-grade tomato powders from double concentrated tomato paste, comparing results with powders obtained by foam mat air drying and freeze dried powders. The principle of this method consists of drying tomato paste in foamed state at low temperatures in vacuum. The formulations were dried at temperatures of 50, 60, and 70 °C and vacuum of 200 mbar. Foam stability was affected by low serum viscosity and the presence of solid particles in tomato paste. Consequently, serum viscosity was increased by maltodextrin addition, yielding optimum stability at tomato paste:maltodextrin ratio of 2.4:1 (w/w) in dry matter. Material foamability was improved by addition of 0.5% (w/w, fresh weight) egg white. Because of solid particles in tomato paste, foam air filling had to be limited to critical air volume fraction of Φ = 0.7. The paste was first pre-foamed to Φ = 0.2 and subsequently expanded in vacuo. After drying to a moisture content of 5.6% to 7.5% wet base (w.b.), the materials obtained were in glassy state. Qualities of the resulting powders were compared with those produced by freeze and air drying. Total color changes were the least after vacuum drying, whereas air drying resulted in noticeable color changes. Vacuum foam drying at 50 °C led to insignificant carotenoid losses, being equivalent to the time-consuming freeze drying method. In contrast, air drying caused lycopene and β-carotene losses of 18% to 33% and 14% to 19% respectively. Thus, vacuum foam drying enables production of high-grade tomato powders being qualitatively similar to powders obtained by freeze drying. © 2015 Institute of Food Technologists®

  7. Dynamical electron diffraction simulation for non-orthogonal crystal system by a revised real space method.

    Science.gov (United States)

    Lv, C L; Liu, Q B; Cai, C Y; Huang, J; Zhou, G W; Wang, Y G

    2015-01-01

    In the transmission electron microscopy, a revised real space (RRS) method has been confirmed to be a more accurate dynamical electron diffraction simulation method for low-energy electron diffraction than the conventional multislice method (CMS). However, the RRS method can be only used to calculate the dynamical electron diffraction of orthogonal crystal system. In this work, the expression of the RRS method for non-orthogonal crystal system is derived. By taking Na2 Ti3 O7 and Si as examples, the correctness of the derived RRS formula for non-orthogonal crystal system is confirmed by testing the coincidence of numerical results of both sides of Schrödinger equation; moreover, the difference between the RRS method and the CMS for non-orthogonal crystal system is compared at the accelerating voltage range from 40 to 10 kV. Our results show that the CMS method is almost the same as the RRS method for the accelerating voltage above 40 kV. However, when the accelerating voltage is further lowered to 20 kV or below, the CMS method introduces significant errors, not only for the higher-order Laue zone diffractions, but also for zero-order Laue zone. These indicate that the RRS method for non-orthogonal crystal system is necessary to be used for more accurate dynamical simulation when the accelerating voltage is low. Furthermore, the reason for the increase of differences between those diffraction patterns calculated by the RRS method and the CMS method with the decrease of the accelerating voltage is discussed. © 2015 The Authors Journal of Microscopy © 2015 Royal Microscopical Society.

  8. Evaluation of gamma prime volume fractions and lattice misfits in a nickel base superalloy using the external standard X-ray diffraction method

    Energy Technology Data Exchange (ETDEWEB)

    Tiley, J., E-mail: jaimie.tiley@wpafb.af.mil [Air Force Research Laboratory, Materials and Manufacturing Directorate, WPAFB, OH (United States); Viswanathan, G.B. [Air Force Research Laboratory, Materials and Manufacturing Directorate, WPAFB, OH (United States); Hwang, J.Y. [Materials Engineering Department, University of North Texas, Denton, TX (United States); Shiveley, A. [Air Force Research Laboratory, Materials and Manufacturing Directorate, WPAFB, OH (United States); Banerjee, R. [Materials Engineering Department, University of North Texas, Denton, TX (United States)

    2010-11-25

    The unconstrained lattice parameters and volume fractions of {gamma}' for a low misfit nickel based superalloy were evaluated using X-ray diffraction techniques. Extraction techniques were used to provide unconstrained {gamma}' powders for both water quenched and slow cooled samples that were aged at 760 deg. C for 0, 25, 50, 100, and 200 h. The external standard method was used to determine the volume fraction for the unaged water quenched sample and the slow cooled sample aged for 200 h. These two extremes in processing conditions provided an increase in the total volume fraction of {gamma}'.

  9. Quantitative phase analysis of uranium carbide from x-ray diffraction data using the Rietveld method

    International Nuclear Information System (INIS)

    Singh Mudher, K.D.; Krishnan, K.

    2003-01-01

    Quantitative phase analysis of a uranium carbide sample was carried out from the x-ray diffraction data by Rietveld profile fitting method. The method does not require the addition of any reference material. The percentage of UC, UC 2 and UO 2 phases in the sample were determined. (author)

  10. On error estimation in the fourier modal method for diffractive gratings

    NARCIS (Netherlands)

    Hlod, A.; Maubach, J.M.L.

    2010-01-01

    The Fourier Modal Method (FMM, also called the Rigorous Coupled Wave Analysis, RCWA) is a numerical discretization method which is often used to calculate a scattered field from a periodic diffraction grating. For 1D periodic gratings in FMM the electromagnetic field is presented by a truncated

  11. A practical method for target preparation of powdered materials

    International Nuclear Information System (INIS)

    Sugai, Isao.

    1977-01-01

    This is the sixth report on the practical method of target preparation for use in nuclear physics experiments following the previous one (INS-TL-131, 1976). We have made various targets by developing the centrifugal precipitation method, which is particularly effective in the cases; (a) metal with high melting point and low vapor pressure, (b) oxides which are difficult to prepare by the usual vacuum evaporation technique and (c) some enriched isotopes which are very minute in quantity (less than - 10 mg) and low in recovery ratio. The samples were once suspended in liquid paraffin by ultrasonic wave vibrator, and then centrifugally precipitated on a thin backing foil such as Mylar or aluminum set and the bottom of the centrifugal tube. Uniformity of target made in this way was checked by an 24 Am-α ray thickness gauge. Contaminations smudged in the preparing process were checked by irradiating the targets with the proton beam from the FM Cyclotron at I.N.S. (auth.)

  12. Bulk synthesis of nanocrystalline urania powders by citrate gel-combustion method

    Science.gov (United States)

    Sanjay Kumar, D.; Ananthasivan, K.; Venkata Krishnan, R.; Amirthapandian, S.; Dasgupta, Arup

    2016-01-01

    Bulk quantities (60 g) of nanocrystalline (nc) free flowing urania powders with crystallite size ranging from 38 to 252 nm have been synthesized for the first time by the citrate gel combustion method. A systematic study of the influence of the fuel (citric acid) to oxidant (nitrate) ratio (R) on the characteristics of the urania powders has been carried out for the first time. Mixture with an "R" value of 0.25 exhibited a vigorous auto-ignition reaction. This reaction was investigated with Differential Scanning Calorimetry (DSC) and in-situ thermogravimetry coupled with differential thermal analysis and mass spectrometry (TG-DTA-MS). The bulk density, specific surface area, X-ray crystallite size, residual carbon and size distribution of particles of this powder were unique. Microscopic and microstructural investigation of selected samples revealed the presence of nanocrystals with irregular exfoliated morphology; their Electron Energy Loss Spectra testified the covalency of the U-O bond.

  13. Influence of the milling time in the microstructural parameters of TA2O5-Al powder refined by Rietveld method

    International Nuclear Information System (INIS)

    Brito, R.A.; Mendes, M.W.D.; Alves Junior, C.; Costa, F.A. da; Gomes, U.U.

    2009-01-01

    Mechanical alloying (MA) is a solid-state powder processing technique involving repeated welding, fracturing, and re-welding of powder particles in a high energy mill. This process is used for producing of fine powders containing unique microstructures. The process starts with mixing of the powders in the desired proportion. Then, the mixture is milled using the established time in the high-energy mill. The powder particles are submitted to repeated cycles of cold working and fracture, and the final product correspond to a composite powder, containing characteristics different of the initial constituents. Ta 2 O 5 -Al powders were milled in a planetary ball mill for different times in order to evaluate the influence of the milling time in their microstructural parameters like crystallite size and micro deformation. The microstructural parameters were obtained by the Rietveld Method. The results showed that the microstructural parameters were influenced by the increase of the milling time. (author)

  14. Hard X-ray nanoimaging method using local diffraction from metal wire

    Energy Technology Data Exchange (ETDEWEB)

    Takano, Hidekazu, E-mail: htakano@sci.u-hyogo.ac.jp; Konishi, Shigeki; Shimomura, Sho; Azuma, Hiroaki; Tsusaka, Yoshiyuki; Kagoshima, Yasushi [Center for Novel Material Science under Multi-Extreme Conditions, Graduate School of Material Science, University of Hyogo, Kamigori, Hyogo 678-1297 (Japan)

    2014-01-13

    A simple hard X-ray imaging method achieving a high spatial resolution is proposed. Images are obtained by scanning a metal wire through the wave field to be measured and rotating the sample to collect data for back projection calculations; the local diffraction occurring at the edges of the metal wire operates as a narrow line probe. In-line holograms of a test sample were obtained with a spatial resolution of better than 100 nm. The potential high spatial resolution of this method is shown by calculations using diffraction theory.

  15. Modeling laser beam diffraction and propagation by the mode-expansion method.

    Science.gov (United States)

    Snyder, James J

    2007-08-01

    In the mode-expansion method for modeling propagation of a diffracted beam, the beam at the aperture can be expanded as a weighted set of orthogonal modes. The parameters of the expansion modes are chosen to maximize the weighting coefficient of the lowest-order mode. As the beam propagates, its field distribution can be reconstructed from the set of weighting coefficients and the Gouy phase of the lowest-order mode. We have developed a simple procedure to implement the mode-expansion method for propagation through an arbitrary ABCD matrix, and we have demonstrated that it is accurate in comparison with direct calculations of diffraction integrals and much faster.

  16. Synthesis of porous graphene powder through improved Hummers' method

    Science.gov (United States)

    Gupta, Siddhant; Bonageri, Shrilakshmi; Achar, Siddarth Krishnaraja; Menon, Atul; Basavaraja R., J.

    2018-05-01

    Graphene due to its high specific surface area is considered to be a potential adsorbent for air and water purification systems. In this study, graphene was synthesized using the recently developed Improved Hummers' method to achieve a high oxidation rate and thermal treatment of the synthesized graphene was done to increase its pore size and make it more capable for applications in purification systems. Graphite flakes were oxidized to obtain graphene oxide which was then reduced to obtain graphene. The synthesized graphene was then thermally treated at 200 °C for two hours in a muffle furnace to improve its surface properties. The characterization results of graphene oxide and graphene show the presence of many impurities which is inferred to be the result of contaminated water used in the experimentation. The analysis of the characterization results also shows that the thermally treated graphene has more spacing and voids when compared to graphene which makes it a better suit for adsorption of gases such as carbon dioxide.

  17. Synthesis and Characterization of Hydroxyapatite Powder by Wet Precipitation Method

    Science.gov (United States)

    Cahyaningrum, S. E.; Herdyastuty, N.; Devina, B.; Supangat, D.

    2018-01-01

    Hydroxyapatite is main inorganic component of the bone with formula Ca10(PO4)6(OH)2. Hydroxyapatite can be used as substituted bone biomaterial because biocompatible, non toxic, and osteoconductive. In this study, hydroxyapatite is synthesized using wet precipitation method from egg shell. The product was sintered at different temperatures of 800°C to 1000°C to improve its crystallinity. The hydroxyapatite was characterized by X-ray analysis, Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR) to reveal its phase content, morphology and types of bond present within it. The analytical results showed hydroxyapatite had range in crystallinity from 85.527 to 98.753%. The analytical functional groups showed that presence of functional groups such as OH, (PO4)3 2-, and CO3 2- that indicated as hydroxyapatite. The result of characterization SEM indicated that hydroxyapatite without sintering and HAp sintering at 800 °C were irregular shape without pore. The best hydroxyapatite with temperature sintering at 900 °C showed oval shaped with pores without agglomerated.

  18. Dispersoid reinforced alloy powder and method of making

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Iver E.; Terpstra, Robert L.

    2017-12-05

    A method of making dispersion-strengthened alloy particles involves melting an alloy having a corrosion and/or oxidation resistance-imparting alloying element, a dispersoid-forming element, and a matrix metal wherein the dispersoid-forming element exhibits a greater tendency to react with a reactive species acquired from an atomizing gas than does the alloying element. The melted alloy is atomized with the atomizing gas including the reactive species to form atomized particles so that the reactive species is (a) dissolved in solid solution to a depth below the surface of atomized particles and/or (b) reacted with the dispersoid-forming element to form dispersoids in the atomized particles to a depth below the surface of said atomized particles. The atomized alloy particles are solidified as solidified alloy particles or as a solidified deposit of alloy particles. Bodies made from the dispersion strengthened alloy particles, deposit thereof, exhibit enhanced fatigue and creep resistance and reduced wear as well as enhanced corrosion and/or oxidation resistance at high temperatures by virtue of the presence of the corrosion and/or oxidation resistance imparting alloying element in solid solution in the particle alloy matrix.

  19. Dispersoid reinforced alloy powder and method of making

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Iver E.; Terpstra, Robert L.

    2017-10-10

    A method of making dispersion-strengthened alloy particles involves melting an alloy having a corrosion and/or oxidation resistance-imparting alloying element, a dispersoid-forming element, and a matrix metal wherein the dispersoid-forming element exhibits a greater tendency to react with a reactive species acquired from an atomizing gas than does the alloying element. The melted alloy is atomized with the atomizing gas including the reactive species to form atomized particles so that the reactive species is (a) dissolved in solid solution to a depth below the surface of atomized particles and/or (b) reacted with the dispersoid-forming element to form dispersoids in the atomized particles to a depth below the surface of said atomized particles. The atomized alloy particles are solidified as solidified alloy particles or as a solidified deposit of alloy particles. Bodies made from the dispersion strengthened alloy particles, deposit thereof, exhibit enhanced fatigue and creep resistance and reduced wear as well as enhanced corrosion and/or oxidation resistance at high temperatures by virtue of the presence of the corrosion and/or oxidation resistance imparting alloying element in solid solution in the particle alloy matrix.

  20. Investigation of the Dependences of the Attenuation Properties of Cryogenic Metal-Powder Filters on the Preparation Method

    Science.gov (United States)

    Lee, Sung Hoon; Lee, Soon-Gul

    2018-04-01

    We fabricated low-pass metal powder filters for use in low-noise measurements at cryogenic temperatures and investigated their attenuation characteristics for different wire-turn densities, metalpowder shapes, and preparation methods at frequencies up to 20 GHz. We used nominally 30-μmsized stainless-steel 304L powder and mixed it with low-temperature binders. The low-temperature binders used were Stycast 2850FT (Emerson and Cumming) with catalyst 23LV and GE-7031 varnish. A 0.1-mm insulated copper wire was wound on preformed powder-mixture bobbins in the shape of a circular rod and was encapsulated in metal tubes with the powder mixture. All the fabricated powder filters showed a large attenuation at high frequencies with a cut-off frequency near 1 GHz. For filters of the same wire length, a lower wiring density showed a larger attenuation, which implies that the amount of powder in close contact with the wire determines the attenuation. Filters made of a powder/varnish mixture showed significantly larger attenuations than those of a powder/stycast mixture, and the attenuation improved with increasing powder ratio in the mixture. The low-temperature thermal conductivities of a 2 : 1 powder/Stycast mixture and a 5 : 1 powder/varnish mixture showed similar values at temperatures up to 4.2 K.

  1. 5-Arylidene derivatives of Meldrum's acid: Synthesis, structural characterization using single crystal and powder crystal X-ray diffraction, and electronic properties

    Science.gov (United States)

    Dey, Tanusri; Ghosh, Soumen; Ghosh, Somnath; Mukherjee, Alok Kumar

    2015-07-01

    Four 5-arylidene derivatives of Meldrum's acid, 5-(4-chlorobenzylidene)-2,2-dimethyl-1,3-dioxane-4,6-dione (2), 5-(3-hydroxybenzylidene)-2,2-dimethyl-1,3-dioxane-4,6-dione (3), 5-(3,4-dimethoxybenzylidene)-2,2-dimethyl-1,3-dioxane-4,6-dione (4) and 5-(2,4-dimethoxy benzylidene)-2,2-dimethyl-1,3-dioxane-4,6-dione (5) have been synthesized and their crystal structures have been determined using single crystal X-ray diffractometry for 2, 4 and 5 and X-ray powder diffraction for 3. The nature of intermolecular interactions in 2-5 has been analyzed through Hirshfeld surfaces and 2D fingerprint plots. The DFT optimized molecular geometries in 2-5 agree closely with those obtained from the crystallographic studies. The crystal packing in 2-5 exhibits an interplay of Osbnd H⋯O, Csbnd H⋯O, Csbnd H⋯Cl and Csbnd H⋯π (arene) hydrogen bonds and π⋯π interactions, which assemble molecules into three-dimensional architecture in 2, 3 and 5 and two-dimensional framework in 4. The Hirshfeld surface analyses of 2-5, Meldrum's acid (1) and a few related 5-arylidene derivatives of Meldrum's acid retrieved from the Cambridge Structural Database (CSD) indicate that about 85% of the Hirshfeld surface area (72% in 2 where H⋯Cl contribution is about 13%) in this class of compounds are due to H⋯H, O⋯H and C⋯H contacts. The HOMO-LUMO energy gap (>2.2 eV) in 2-5 indicates a significant degree of internal charge transfer within the molecule.

  2. An efficient and accurate method for calculating nonlinear diffraction beam fields

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Hyun Jo; Cho, Sung Jong; Nam, Ki Woong; Lee, Jang Hyun [Division of Mechanical and Automotive Engineering, Wonkwang University, Iksan (Korea, Republic of)

    2016-04-15

    This study develops an efficient and accurate method for calculating nonlinear diffraction beam fields propagating in fluids or solids. The Westervelt equation and quasilinear theory, from which the integral solutions for the fundamental and second harmonics can be obtained, are first considered. A computationally efficient method is then developed using a multi-Gaussian beam (MGB) model that easily separates the diffraction effects from the plane wave solution. The MGB models provide accurate beam fields when compared with the integral solutions for a number of transmitter-receiver geometries. These models can also serve as fast, powerful modeling tools for many nonlinear acoustics applications, especially in making diffraction corrections for the nonlinearity parameter determination, because of their computational efficiency and accuracy.

  3. Synthesis of Black and Red Mercury Sulfide Nano-Powder by Traditional Indian Method for Biomedical Application

    International Nuclear Information System (INIS)

    Padhi, Payodhar; Sahoo, G.; Das, K.; Ghosh, Sudipto; Panigrahi, S. C.

    2008-01-01

    physicians could get rid of free mercury by milling and proper choice of the ratio of ingredients as is shown in the investigation by X-ray diffraction studies. In the traditional method for synthesis of mercury sulfide, mercury and pure sulfur were taken and milled in a mortar and pastel. During milling process, the white mercury and yellow sulfur yielded to a gray black colored sulfide. Synthesis of red sulfide of mercury required additional steps of heating and subsequent milling. For therapeutically application, the sulfide thus obtained needed detoxification, which was done using organic extracts. In the present investigation, the same method was followed to synthesize the sapphires and the product was characterized using modern methods like XRD, SEM and HRTEM. With increase in milling time the fineness of the powder increases, which increases the efficacy of the medicine, and free mercury, which is not desirable for medicinal application is found to decrease. The powder obtained at the end of 48 hours of milling is found to be of a size finer than l0nm.

  4. Synthesis of Black and Red Mercury Sulfide Nano-Powder by Traditional Indian Method for Biomedical Application

    Science.gov (United States)

    Padhi, Payodhar; Sahoo, G.; Das, K.; Ghosh, Sudipto; Panigrahi, S. C.

    2008-10-01

    physicians could get rid of free mercury by milling and proper choice of the ratio of ingredients as is shown in the investigation by X-ray diffraction studies. In the traditional method for synthesis of mercury sulfide, mercury and pure sulfur were taken and milled in a mortar and pastel. During milling process, the white mercury and yellow sulfur yielded to a gray black colored sulfide. Synthesis of red sulfide of mercury required additional steps of heating and subsequent milling. For therapeutically application, the sulfide thus obtained needed detoxification, which was done using organic extracts. In the present investigation, the same method was followed to synthesize the sapphires and the product was characterized using modern methods like XRD, SEM and HRTEM. With increase in milling time the fineness of the powder increases, which increases the efficacy of the medicine, and free mercury, which is not desirable for medicinal application is found to decrease. The powder obtained at the end of 48 hours of milling is found to be of a size finer than l0nm.

  5. Effect of Gallium and Indium Co-Substituting on Upconversion Properties of Er/Yb:Yttrium Aluminum Garnet Powders Prepared by the Co-Precipitation Method.

    Science.gov (United States)

    Zhang, Wei; Liang, Yun-Ling; Hu, Zheng-Fa; Feng, Zu-Yong; Lun, Ma; Zhang, Xiu-ping; Sheng, Xia; Liu, Qian; Luo, Jie

    2016-04-01

    Gallium and Indium co-substituted Yb, Er:YAG was fabricated through the chemical co-precipitation method. The formation process and structure of the Ga3+ and In3+ substituted phosphor powders were characterized by the X-ray diffraction, thermo-gravimetry analyzer, infrared spectra, and X-ray photoelectron spectroscopy, and the effects of Ga3+ and In3+ concentration on the luminescence properties were investigated by spectrum. The results showed that the blue shift occurred after the substitution of Ga3+ and In3+ for Al3+ in matrix, and the intensity of emission spectrum was affected by the concentration of Ga3+ and In3+.

  6. X-ray diffraction 2 - diffraction principles

    International Nuclear Information System (INIS)

    O'Connor, B.

    1999-01-01

    Full text: The computation of powder diffraction intensities is based on the principle that the powder pattern comprises the summation of the intensity contributions from each of the crystallites (or single crystals) in the material. Therefore, it is of value for powder diffractionists to appreciate the form of the expression for calculating single crystal diffraction pattern intensities. This knowledge is especially important for Rietveld analysis practitioners in terms of the (i) mathematics of the method and (ii) retrieving single crystal structure data from the literature. We consider the integrated intensity from a small single crystal being rotated at velocity ω through the Bragg angle θ for reflection (hkl).... I(hkl) = [l o /ω]. [e 4 /m 2 c 4 ]. [λ 3 δV F(hkl) 2 /υ 2 ].[(1+cos 2 2θ)/2sin2θ] where e, m and c are the usual fundamental constants; λ is the x-ray wavelength, δV is the crystallite volume; F(hkl) is the structure factor; υ is the unit cell volume; and (1+cos 2 θ)/2sin2θ] is the Lorentz-polarisation factor for an unpolarised incident beam. The expression does not include a contribution for extinction. The influence of factors λ, δV, F(hkl) and υ on the intensities should be appreciated by powder diffractionists, especially the structure factor, F(hkl), which is responsible for the fingerprint nature of diffraction patterns, such as the rise and fall of intensity from peak to peak. The structure factor expression represents the summation of the scattered waves from each of the j scattering centres (i e atoms) in the unit cell: F(hkl) Σ f j exp[2πi (h.x j +k.y i +l. z i )] T j . Symbol f is the scattering factor (representing the atom-type scattering efficiency); (x, y, z) are the fractional position coordinates of atom j within the unit cell; and T is the thermal vibration factor for the atom given by: T j = 8π 2 2 > sin 2 θ/λ 2 with 2 > being the mean-square vibration amplitude of the atom (assumed to be isotropic). The

  7. A Spatially Offset Raman Spectroscopy Method for Non-Destructive Detection of Gelatin-Encapsulated Powders

    Directory of Open Access Journals (Sweden)

    Kuanglin Chao

    2017-03-01

    Full Text Available Non-destructive subsurface detection of encapsulated, coated, or seal-packaged foods and pharmaceuticals can help prevent distribution and consumption of counterfeit or hazardous products. This study used a Spatially Offset Raman Spectroscopy (SORS method to detect and identify urea, ibuprofen, and acetaminophen powders contained within one or more (up to eight layers of gelatin capsules to demonstrate subsurface chemical detection and identification. A 785-nm point-scan Raman spectroscopy system was used to acquire spatially offset Raman spectra for an offset range of 0 to 10 mm from the surfaces of 24 encapsulated samples, using a step size of 0.1 mm to obtain 101 spectral measurements per sample. As the offset distance was increased, the spectral contribution from the subsurface powder gradually outweighed that of the surface capsule layers, allowing for detection of the encapsulated powders. Containing mixed contributions from the powder and capsule, the SORS spectra for each sample were resolved into pure component spectra using self-modeling mixture analysis (SMA and the corresponding components were identified using spectral information divergence values. As demonstrated here for detecting chemicals contained inside thick capsule layers, this SORS measurement technique coupled with SMA has the potential to be a reliable non-destructive method for subsurface inspection and authentication of foods, health supplements, and pharmaceutical products that are prepared or packaged with semi-transparent materials.

  8. Optimisation Of Process Parameters In High Energy Mixing As A Method Of Cohesive Powder Flowability Improvement

    Directory of Open Access Journals (Sweden)

    Leś Karolina

    2015-12-01

    Full Text Available Flowability of fine, highly cohesive calcium carbonate powder was improved using high energy mixing (dry coating method consisting in coating of CaCO3 particles with a small amount of Aerosil nanoparticles in a planetary ball mill. As measures of flowability the angle of repose and compressibility index were used. As process variables the mixing speed, mixing time, and the amount of Aerosil and amount of isopropanol were chosen. To obtain optimal values of the process variables, a Response Surface Methodology (RSM based on Central Composite Rotatable Design (CCRD was applied. To match the RSM requirements it was necessary to perform a total of 31 experimental tests needed to complete mathematical model equations. The equations that are second-order response functions representing the angle of repose and compressibility index were expressed as functions of all the process variables. Predicted values of the responses were found to be in a good agreement with experimental values. The models were presented as 3-D response surface plots from which the optimal values of the process variables could be correctly assigned. The proposed, mechanochemical method of powder treatment coupled with response surface methodology is a new, effective approach to flowability of cohesive powder improvement and powder processing optimisation.

  9. Functional coordination polymers and MOFs from reactions of the lanthanides and barium with azole ligands. Synthesis and characterization with a focus on structure determination from X-ray powder diffraction data; Funktionale Koordinationspolymere und MOFs aus Reaktionen der Lanthanide und des Bariums mit Azol-Liganden. Synthese und Charakterisierung mit dem Fokus der Strukturbestimmung anhand von Roentgenpulverbeugungsdaten

    Energy Technology Data Exchange (ETDEWEB)

    Rybak, Jens-Christoph

    2012-07-01

    }[BaEu(Im){sub 2}]. Structural characterization of materials from X-ray powder diffraction data is an important aspect of this thesis. A method is presented, which allows, by indexing a diffractogram, intensity extraction and structure solution by charge flipping, to solve the structure of a material, ab initio, from X-ray powder diffraction data exclusively. Moreover it is shown how to refine structures with a high amount of weakly scattering atoms, using rigid body constraints. The structure solutions of {sup 3}{sub ∞}[Ga(Tz){sub 2}], {sup 3}{sub ∞}[Sr(Im){sub 2}]:Ce and {sup 3}{sub ∞}[Yb(Im){sub 3}]ImH from X-ray powder diffraction data are further examples for the successful application of the method presented within this thesis.

  10. Temperature gradient method for lipid phase diagram construction using time-resolved x-ray diffraction

    International Nuclear Information System (INIS)

    Caffrey, M.; Hing, F.S.

    1987-01-01

    A method that enables temperature-composition phase diagram construction at unprecedented rates is described and evaluated. The method involves establishing a known temperature gradient along the length of a metal rod. Samples of different compositions contained in long, thin-walled capillaries are positioned lengthwise on the rod and equilibrated such that the temperature gradient is communicated into the sample. The sample is then moved through a focused, monochromatic synchrotron-derived x-ray beam and the image-intensified diffraction pattern from the sample is recorded on videotape continuously in live-time as a function of position and, thus, temperature. The temperature at which the diffraction pattern changes corresponds to a phase boundary, and the phase(s) existing (coexisting) on either side of the boundary can be identified on the basis of the diffraction pattern. Repeating the measurement on samples covering the entire composition range completes the phase diagram. These additional samples can be conveniently placed at different locations around the perimeter of the cylindrical rod and rotated into position for diffraction measurement. Temperature-composition phase diagrams for the fully hydrated binary mixtures, dimyristoylphosphatidylcholine (DMPC)/dipalmitoylphosphatidylcholine (DPPC) and dipalmitoylphosphatidylethanolamine (DPPE)/DPPC, have been constructed using the new temperature gradient method. They agree well with and extend the results obtained by other techniques. In the DPPE/DPPC system structural parameters as a function of temperature in the various phases including the subgel phase are reported. The potential limitations of this steady-state method are discussed

  11. A greedy method for reconstructing polycrystals from three-dimensional X-ray diffraction data

    DEFF Research Database (Denmark)

    Kulshreshth, Arun Kumar; Alpers, Andreas; Herman, Gabor T.

    2009-01-01

    An iterative search method is proposed for obtaining orientation maps inside polycrystals from three-dimensional X-ray diffraction (3DXRD) data. In each step, detector pixel intensities are calculated by a forward model based on the current estimate of the orientation map. The pixel at which...

  12. Long wave-length x-ray diffraction crystal and method of manufacturing same

    International Nuclear Information System (INIS)

    Zingaro, W.P.; Sicignano, A.

    1980-01-01

    An x-ray diffraction crystal of the Langemuir-Blodgett type capable of detecting radiation having a wavelength greater than 50 Arystroms and a method of making such a crystal are described. The crystal consists of a pair of alternate monolayers, one a heavy metal soap, and one a light metal soap. Selecting cation pairs with a significant difference in atomic number and dispersing power, such as Pb and Be, Mg, or Ca, increases the effective interplanar distance since the Pb planes cause the predominant x-ray diffraction. (LL)

  13. Sintering behaviour of CeO2-Gd2O3 powders prepared by the oxalate coprecipitation method

    International Nuclear Information System (INIS)

    Duran, P.; Jurado, J.R.; Moure, C.

    1993-01-01

    The powder and compact characteristics as well as the sintering behaviour of two CeO 2 -Gd 2 O 3 compositions prepared by the oxalate coprecipitation method are studied as a function of the powder particle size and the pore-size distribution in the powder compacts. Shrinkage was measured at a constant heating rate and the results are compared with those obtained by isothermal sintering experiments. Grain growth and microstructural development on sintered samples were studied. (orig.)

  14. Applications of the Warren-Averbach method of X-ray diffraction line profile analysis

    International Nuclear Information System (INIS)

    Ichikawa, Rodrigo Uchida

    2013-01-01

    The objective of this work was to develop and implement a methodology of X-ray Line Profile Analysis (XLPA) for the study and determination of the mean crystallite sizes and microstrains in materials. A computer program was developed to speed up the treatment of diffraction peaks and perform the deconvolution utilizing the Stokes method to correct the instrumental contribution in the X-ray diffraction measurements. The XLPA methods used were the Scherrer, Williamson-Hall and Single-Line methods, which can be called real space methods, and the Fourier space method of Warren-Averbach. Furthermore, considering a mathematical modelling it was possible to calculate the crystallite size distribution, considering the log-normal distribution and spherical crystallites. It was possible to demonstrate the proposed theory can provide reliable results evaluating a dispersion parameter. The methodologies described above were applied in two distinct materials: in the alloy Zircaloy-4 and in ZnO. (author)

  15. Characteristics of nano Ti-doped SnO2 powders prepared by sol-gel method

    International Nuclear Information System (INIS)

    Liu, X.M.; Wu, S.L.; Chu, Paul K.; Zheng, J.; Li, S.L.

    2006-01-01

    Ti 4+ -doped SnO 2 nano-powders were prepared by the sol-gel process using tin tetrachloride and titanium tetrachloride as the starting materials. The crystallinity and purity of the powders were analyzed by X-ray diffraction (XRD) and the size and distribution of Ti 4+ -doped SnO 2 grains were studied using transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The results show that Ti 4+ has been successfully incorporated into the SnO 2 crystal lattice and the electrical conductivity of the doped materials improves significantly

  16. Introducing a novel gravitation-based high-velocity compaction analysis method for pharmaceutical powders.

    Science.gov (United States)

    Tanner, Timo; Antikainen, Osmo; Ehlers, Henrik; Yliruusi, Jouko

    2017-06-30

    With modern tableting machines large amounts of tablets are produced with high output. Consequently, methods to examine powder compression in a high-velocity setting are in demand. In the present study, a novel gravitation-based method was developed to examine powder compression. A steel bar is dropped on a punch to compress microcrystalline cellulose and starch samples inside the die. The distance of the bar is being read by a high-accuracy laser displacement sensor which provides a reliable distance-time plot for the bar movement. In-die height and density of the compact can be seen directly from this data, which can be examined further to obtain information on velocity, acceleration and energy distribution during compression. The energy consumed in compact formation could also be seen. Despite the high vertical compression speed, the method was proven to be cost-efficient, accurate and reproducible. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Development of high performance liquid chromatography method for miconazole analysis in powder sample

    Science.gov (United States)

    Hermawan, D.; Suwandri; Sulaeman, U.; Istiqomah, A.; Aboul-Enein, H. Y.

    2017-02-01

    A simple high performance liquid chromatography (HPLC) method has been developed in this study for the analysis of miconazole, an antifungal drug, in powder sample. The optimized HPLC system using C8 column was achieved using mobile phase composition containing methanol:water (85:15, v/v), a flow rate of 0.8 mL/min, and UV detection at 220 nm. The calibration graph was linear in the range from 10 to 50 mg/L with r 2 of 0.9983. The limit of detection (LOD) and limit of quantitation (LOQ) obtained were 2.24 mg/L and 7.47 mg/L, respectively. The present HPLC method is applicable for the determination of miconazole in the powder sample with a recovery of 101.28 % (RSD = 0.96%, n = 3). The developed HPLC method provides short analysis time, high reproducibility and high sensitivity.

  18. Effects of Process Parameters on Copper Powder Compaction Process Using Multi-Particle Finite Element Method

    Science.gov (United States)

    Güner, F.; Sofuoğlu, H.

    2018-01-01

    Powder metallurgy (PM) has been widely used in several industries; especially automotive and aerospace industries and powder metallurgy products grow up every year. The mechanical properties of the final product that is obtained by cold compaction and sintering in powder metallurgy are closely related to the final relative density of the process. The distribution of the relative density in the die is affected by parameters such as compaction velocity, friction coefficient and temperature. Moreover, most of the numerical studies utilizing finite element approaches treat the examined environment as a continuous media with uniformly homogeneous porosity whereas Multi-Particle Finite Element Method (MPFEM) treats every particles as an individual body. In MPFEM, each of the particles can be defined as an elastic- plastic deformable body, so the interactions of the particles with each other and the die wall can be investigated. In this study, each particle was modelled and analyzed as individual deformable body with 3D tetrahedral elements by using MPFEM approach. This study, therefore, was performed to investigate the effects of different temperatures and compaction velocities on stress distribution and deformations of copper powders of 200 µm-diameter in compaction process. Furthermore, 3-D MPFEM model utilized von Mises material model and constant coefficient of friction of μ=0.05. In addition to MPFEM approach, continuum modelling approach was also performed for comparison purposes.

  19. Synthesis and characterization of lead zirconate titanate powders obtained by the oxidant peroxo method

    Energy Technology Data Exchange (ETDEWEB)

    Camargo, Emerson R. [LIEC-Laboratorio Interdisciplinar de Eletroquimica e Ceramica, Department of Chemistry, UFSCar-Federal University of Sao Carlos, Rod. Washington Luis km 235, CP 676, Sao Carlos SP, 13565-905 (Brazil)], E-mail: camargo@ufscar.br; Leite, Edson R. [LIEC-Laboratorio Interdisciplinar de Eletroquimica e Ceramica, Department of Chemistry, UFSCar-Federal University of Sao Carlos, Rod. Washington Luis km 235, CP 676, Sao Carlos SP, 13565-905 (Brazil)], E-mail: derl@power.ufscar.br; Longo, Elson [Department of Biochemistry, Chemistry Institute of Araraquara, UNESP, Sao Paulo State University Rua Francisco Degni, CP 355 Araraquara SP, 14801-907 Brazil (Brazil)], E-mail: elson@iq.unesp.br

    2009-02-05

    Lead zirconate titanate (PbZr{sub 1-x}Ti{sub x}O{sub 3}) was synthesized by the 'oxidant peroxo method (OPM)' with 'x' between 0.25 and 0.50. Titanium metal was dissolved into a hydrogen peroxide/ammonia aqueous solution, followed by the addition of lead and zirconium nitrate solution. The amorphous precipitated precursor obtained was crystallized by heat treatment between 400 and 1000 deg. C. Images of transmission microscopy showed spherical particles with average diameter between 20 and 60 nm, and the presence of necks between particles treated at 700 deg. C. All of the unpressed powders were characterized by X-ray diffractometry and FT-Raman spectroscopy. Powder samples with 'x' up to 0.35 showed rhombohedral structure when treated at temperatures higher than 500 deg. C, and tetragonal structure when 'x' was higher than 0.40. Analysis of XRD and Raman spectroscopy of the precursor powders showed amorphous-like structures, however powders treated at 400 deg. C showed a structure identified as an intermediate pyrochlore phase, independently of the Zr and Ti mole ratio.

  20. Synthesis and characterization of lead zirconate titanate powders obtained by the oxidant peroxo method

    International Nuclear Information System (INIS)

    Camargo, Emerson R.; Leite, Edson R.; Longo, Elson

    2009-01-01

    Lead zirconate titanate (PbZr 1-x Ti x O 3 ) was synthesized by the 'oxidant peroxo method (OPM)' with 'x' between 0.25 and 0.50. Titanium metal was dissolved into a hydrogen peroxide/ammonia aqueous solution, followed by the addition of lead and zirconium nitrate solution. The amorphous precipitated precursor obtained was crystallized by heat treatment between 400 and 1000 deg. C. Images of transmission microscopy showed spherical particles with average diameter between 20 and 60 nm, and the presence of necks between particles treated at 700 deg. C. All of the unpressed powders were characterized by X-ray diffractometry and FT-Raman spectroscopy. Powder samples with 'x' up to 0.35 showed rhombohedral structure when treated at temperatures higher than 500 deg. C, and tetragonal structure when 'x' was higher than 0.40. Analysis of XRD and Raman spectroscopy of the precursor powders showed amorphous-like structures, however powders treated at 400 deg. C showed a structure identified as an intermediate pyrochlore phase, independently of the Zr and Ti mole ratio

  1. The influence of direct compression powder blend transfer method from the container to the tablet press on product critical quality attributes: a case study.

    Science.gov (United States)

    Teżyk, Michał; Jakubowska, Emilia; Milczewska, Kasylda; Milanowski, Bartłomiej; Voelkel, Adam; Lulek, Janina

    2017-06-01

    The aim of this article is to compare the gravitational powder blend loading method to the tablet press and manual loading in terms of their influence on tablets' critical quality attributes (CQA). The results of the study can be of practical relevance to the pharmaceutical industry in the area of direct compression of low-dose formulations, which could be prone to content uniformity (CU) issues. In the preliminary study, particle size distribution (PSD) and surface energy of raw materials were determined using laser diffraction method and inverse gas chromatography, respectively. For trials purpose, a formulation containing two pharmaceutical ingredients (APIs) was used. Tablet samples were collected during the compression progress to analyze their CQAs, namely assay and CU. Results obtained during trials indicate that tested direct compression powder blend is sensitive to applied powder handling method. Mild increase in both APIs content was observed during manual scooping. Gravitational approach (based on discharge into the drum) resulted in a decrease in CU, which is connected to a more pronounced assay increase at the end of tableting than in the case of manual loading. The correct design of blend transfer over single unit processes is an important issue and should be investigated during the development phase since it may influence the final product CQAs. The manual scooping method, although simplistic, can be a temporary solution to improve the results of API's content and uniformity when compared to industrial gravitational transfer.

  2. Assessment of the optimum degree of Sr{sub 3}Fe{sub 2}MoO{sub 9} electron-doping through oxygen removal: An X-ray powder diffraction and {sup 57}Fe Moessbauer spectroscopy study

    Energy Technology Data Exchange (ETDEWEB)

    Lopez, Carlos A.; Viola, Maria del C. [Area de Quimica General e Inorganica, Departamento de Quimica, Facultad de Quimica, Bioquimica y Farmacia, Universidad Nacional de San Luis, Chacabuco y Pedernera, 5700 San Luis (Argentina); Pedregosa, Jose C., E-mail: jpedreg@unsl.edu.ar [Area de Quimica General e Inorganica, Departamento de Quimica, Facultad de Quimica, Bioquimica y Farmacia, Universidad Nacional de San Luis, Chacabuco y Pedernera, 5700 San Luis (Argentina); Mercader, Roberto C., E-mail: mercader@fisica.unlp.edu.ar [Departamento de Fisica, IFLP-CONICET, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, C.C. 67, 1900 La Plata (Argentina)

    2010-10-15

    We describe the preparation and structural characterization by X-ray powder diffraction (XRPD) and Moessbauer spectroscopy of three electron-doped perovskites Sr{sub 3}Fe{sub 2}MoO{sub 9-{delta}} with Fe/Mo = 2 obtained from Sr{sub 3}Fe{sub 2}MoO{sub 9}. The compounds were synthesized by topotactic reduction with H{sub 2}/N{sub 2} (5/95) at 600, 700 and 800 {sup o}C. Above 800 {sup o}C the Fe/Mo ratio changes from Fe/Mo = 2-1 < Fe/Mo < 2. The structural refinements of the XRPD data for the reduced perovskites were carried out by the Rietveld profile analysis method. The crystal structure of these phases is cubic, space group Fm3-bar m, with cationic disorder at the two different B sites that can be populated in variable proportions by the Fe atoms. The Moessbauer spectra allowed determining the evolution of the different species formed after the treatments at different temperatures and confirm that Fe ions in the samples reduced at 600, 700 and 800 {sup o}C are only in the high-spin Fe{sup 3+} electronic state.

  3. Molecular structure determination of cyclootane by ab initio and electron diffraction methods in the gas phase

    OpenAIRE

    De Almeida, Wagner B.

    2000-01-01

    The determination of the molecular structure of molecules is of fundamental importance in chemistry. X-rays and electron diffraction methods constitute in important tools for the elucidation of the molecular structure of systems in the solid state and gas phase, respectively. The use of quantum mechanical molecular orbital ab initio methods offer an alternative for conformational analysis studies. Comparison between theoretical results and those obtained experimentally in the gas phase can ma...

  4. Size effect in barium titanate powders synthesized by different hydrothermal methods

    International Nuclear Information System (INIS)

    Sun Weian

    2006-01-01

    The size effect in barium titanate (BaTiO 3 ) was investigated both experimentally and theoretically. Tetragonal BaTiO 3 powders with average sizes from 80 to 420 nm were directly prepared by different hydrothermal methods. The tetragonality of the hydrothermal BaTiO 3 decreased with decreasing particle size, which exhibited a dependence on the synthesis method. A phenomenological model for the size effect was proposed to interpret the experimental observations. The influence of the defects, mainly the lattice hydroxyl, on the size effect was investigated to understand the correlation between the size effect and synthesis condition. The permittivities of BaTiO 3 powder at different particle sizes were calculated, which predicted a maximum permittivity of over 16 000 around the room-temperature critical size of ∼70 nm. The prediction was in good accordance with the experimental data reported recently

  5. Comparison of Titration ICP and XRF Spectrometry Methods in Determination of Cerium in Lens Polishing Powder

    International Nuclear Information System (INIS)

    Ninlaphruk, Sumalee; Pichestapong, Pipat; Mungpayabal, Harinate; Jiyavaranant, Thitima; Srisukho, Supapan; Chaisai, Prapassurn

    2004-10-01

    Three analytical methods in determination of cerium in cerium oxide separated from monazite ore for producing lens polishing powder were compared. These methods are titration ICP and XRF spectrometry techniques. The cerium oxide sample with estimated 45% cerium content needed to be digested and converted into solution before the analysis. The analytical results shown significantly no difference between each method. However, the titration method was found to be more convenient and suitable for quality control in the production of cerium oxide as it does not require standard cerium and the complicated analytical instruments

  6. Probing the role of ceramide hydroxylation in skin barrier lipid models by 2H solid-state NMR spectroscopy and X-ray powder diffraction.

    Science.gov (United States)

    Kováčik, Andrej; Vogel, Alexander; Adler, Juliane; Pullmannová, Petra; Vávrová, Kateřina; Huster, Daniel

    2018-05-01

    In this work, we studied model stratum corneum lipid mixtures composed of the hydroxylated skin ceramides N-lignoceroyl 6-hydroxysphingosine (Cer[NH]) and α-hydroxylignoceroyl phytosphingosine (Cer[AP]). Two model skin lipid mixtures of the composition Cer[NH] or Cer[AP], N-lignoceroyl sphingosine (Cer[NS]), lignoceric acid (C24:0) and cholesterol in a 0.5:0.5:1:1 molar ratio were compared. Model membranes were investigated by differential scanning calorimetry and 2 H solid-state NMR spectroscopy at temperatures from 25 °C to 80 °C. Each component of the model mixture was specifically deuterated for selective detection by 2 H NMR. Thus, the exact phase composition of the mixture at varying temperatures could be quantified. Moreover, using X-ray powder diffraction we investigated the lamellar phase formation. From the solid-state NMR and DSC studies, we found that both hydroxylated Cer[NH] and Cer[AP] exhibit a similar phase behavior. At physiological skin temperature of 32 °C, the lipids form a crystalline (orthorhombic) phase. With increasing temperature, most of the lipids become fluid and form a liquid-crystalline phase, which converts to the isotropic phase at higher temperatures (65-80 °C). Interestingly, lignoceric acid in the Cer[NH]-containing mixture has a tendency to form two types of fluid phases at 65 °C. This tendency was also observed in Cer[AP]-containing membranes at 80 °C. While Cer[AP]-containing lipid models formed a short periodicity phase featuring a repeat spacing of d = 5.4 nm, in the Cer[NH]-based model skin lipid membranes, the formation of unusual long periodicity phase with a repeat spacing of d = 10.7 nm was observed. Copyright © 2018 Elsevier B.V. All rights reserved.

  7. Coherent 3D nanostructure of γ-Al{sub 2}O{sub 3}: Simulation of whole X-ray powder diffraction pattern

    Energy Technology Data Exchange (ETDEWEB)

    Pakharukova, V.P., E-mail: verapakh@catalysis.ru [Boreskov Institute of Catalysis SB RAS, Pr. Lavrentieva 5, 630090 Novosibirsk (Russian Federation); Novosibirsk State University, Pirogova Street 2, 630090 Novosibirsk (Russian Federation); Research and Educational Center for Energy Efficient Catalysis, Novosibirsk State University, Novosibirsk 630090 (Russian Federation); Yatsenko, D.A. [Boreskov Institute of Catalysis SB RAS, Pr. Lavrentieva 5, 630090 Novosibirsk (Russian Federation); Novosibirsk State University, Pirogova Street 2, 630090 Novosibirsk (Russian Federation); Gerasimov, E. Yu.; Shalygin, A.S.; Martyanov, O.N.; Tsybulya, S.V. [Boreskov Institute of Catalysis SB RAS, Pr. Lavrentieva 5, 630090 Novosibirsk (Russian Federation); Novosibirsk State University, Pirogova Street 2, 630090 Novosibirsk (Russian Federation); Research and Educational Center for Energy Efficient Catalysis, Novosibirsk State University, Novosibirsk 630090 (Russian Federation)

    2017-02-15

    The structure and nanostructure features of nanocrystalline γ-Al{sub 2}O{sub 3} obtained by dehydration of boehmite with anisotropic platelet-shaped particles were investigated. The original models of 3D coherent nanostructure of γ-Al{sub 2}O{sub 3} were constructed. The models of nanostructured γ-Al{sub 2}O{sub 3} particles were first confirmed by a direct simulation of powder X–Ray diffraction (XRD) patterns using the Debye Scattering Equation (DSE) with assistance of high-resolution transmission electron microscopy (HRTEM) study. The average crystal structure of γ-Al{sub 2}O{sub 3} was shown to be tetragonally distorted. The experimental results revealed that thin γ-Al{sub 2}O{sub 3} platelets were heterogeneous on a nanometer scale and nanometer-sized building blocks were separated by partially coherent interfaces. The XRD simulation results showed that a specific packing of the primary crystalline blocks in the nanostructured γ-Al{sub 2}O{sub 3} particles with formation of planar defects on (001), (100), and (101) planes nicely accounted for pronounced diffuse scattering, anisotropic peak broadening and peak shifts in the experimental XRD pattern. The identified planar defects in cation sublattice seem to be described as filling cation non-spinel sites in existing crystallographic models of γ-Al{sub 2}O{sub 3} structure. The overall findings provided an insight into the complex nanostructure, which is intrinsic to the metastable γ-Al{sub 2}O{sub 3} oxide. - Highlights: • Thin plate-like crystallites of γ-Al{sub 2}O{sub 3} were obtained. • Models of 3D coherent nanostructure of γ-Al{sub 2}O{sub 3} were constructed. • Models were verified by simulating XRD patterns using the Debye Scattering Equation. • Specific broadening of XRD peaks was explained in terms of planar defects. • Primary crystalline blocks in γ-Al{sub 2}O{sub 3} are separated by partially coherent interfaces.

  8. Structural and microstructural changes during anion exchange of CoAl layered double hydroxides. An in situ X-ray powder diffraction study

    International Nuclear Information System (INIS)

    Johnsen, Rune E.; Krumeich, Frank; Norby, Poul

    2010-01-01

    Anion-exchange processes in cobalt-aluminium layered double hydroxides (LDHs) were studied by in situ synchrotron X-ray powder diffraction (XRPD). The processes investigated were CoAl-CO 3 →CoAl-Cl →CoAl-CO 3 , CoAl-Cl→CoAl-NO 3 and CoAl-CO 3 →CoAl-SO 4 . The XRPD data show that the CoAl-CO 3 →CoAl-Cl process is a two-phase transformation, where the amount of the CoAl-CO 3 phase decreases exponentially while that of the CoAl-Cl phase increases exponentially. Energy-dispersive X-ray spectroscopy (EDXS) studies of a partially chloride-exchanged CoAl-CO 3 LDH sample along with in situ XRPD data suggested that the individual particles in the CoAl-CO 3 sample are generally anion-exchanged with chloride one at a time. In contrast with the CoAl-CO 3 →CoAl-Cl transformation, the XRPD data show that the reverse CoAl-Cl→CoAl-CO 3 process is a one-phase transformation. Rietveld refinements indicate that the occupancy factors of the carbon and oxygen sites of the carbonate group increase, while that of the chloride site decreases. In the CoAl-Cl→CoAl-NO 3 anion-exchange reaction, the XRPD patterns reveal the existence of two intermediate phases in addition to the initial CoAl-Cl and final CoAl-NO 3 phases. The in situ data indicate that one of these intermediates is a mixed nitrate- and chloride-based LDH phase, where the disorder decreases as the nitrate content increases. The XRPD data of the partial CoAl-CO 3 →CoAl-SO 4 anion-exchange reaction show that the process is a two-phase transformation involving a sulfate-containing LDH with a 1H polytype structure. (orig.)

  9. Elucidating the breathing of the metal-organic framework MIL-53(Sc) with ab initio molecular dynamics simulations and in situ X-ray powder diffraction experiments.

    Science.gov (United States)

    Chen, Linjiang; Mowat, John P S; Fairen-Jimenez, David; Morrison, Carole A; Thompson, Stephen P; Wright, Paul A; Düren, Tina

    2013-10-23

    Ab initio molecular dynamics (AIMD) simulations have been used to predict structural transitions of the breathing metal-organic framework (MOF) MIL-53(Sc) in response to changes in temperature over the range 100-623 K and adsorption of CO2 at 0-0.9 bar at 196 K. The method has for the first time been shown to predict successfully both temperature-dependent structural changes and the structural response to variable sorbate uptake of a flexible MOF. AIMD employing dispersion-corrected density functional theory accurately simulated the experimentally observed closure of MIL-53(Sc) upon solvent removal and the transition of the empty MOF from the closed-pore phase to the very-narrow-pore phase (symmetry change from P2(1)/c to C2/c) with increasing temperature, indicating that it can directly take into account entropic as well as enthalpic effects. We also used AIMD simulations to mimic the CO2 adsorption of MIL-53(Sc) in silico by allowing the MIL-53(Sc) framework to evolve freely in response to CO2 loadings corresponding to the two steps in the experimental adsorption isotherm. The resulting structures enabled the structure determination of the two CO2-containing intermediate and large-pore phases observed by experimental synchrotron X-ray diffraction studies with increasing CO2 pressure; this would not have been possible for the intermediate structure via conventional methods because of diffraction peak broadening. Furthermore, the strong and anisotropic peak broadening observed for the intermediate structure could be explained in terms of fluctuations of the framework predicted by the AIMD simulations. Fundamental insights from the molecular-level interactions further revealed the origin of the breathing of MIL-53(Sc) upon temperature variation and CO2 adsorption. These simulations illustrate the power of the AIMD method for the prediction and understanding of the behavior of flexible microporous solids.

  10. Formation of polycrystalline MgB2 synthesized by powder in sealed tube method with different initial boron phase

    Science.gov (United States)

    Yudanto, Sigit Dwi; Imaduddin, Agung; Kurniawan, Budhy; Manaf, Azwar

    2018-04-01

    Magnesium diboride, MgB2 is a new high critical temperature superconductor that discovered in the beginning of the 21st century. The MgB2 has a simple crystal structure and a high critical temperature, which can be manufactured in several forms like thin films, tapes, wires including bulk in the large scale. For that reason, the MgB2 has good prospects for various applications in the field of electronic devices. In the current work, we have explored the synthesis of MgB2 polycrystalline using powder in a sealed tube method. Different initial boron phase for the synthesized of MgB2 polycrystalline were used. These were, in addition to magnesium powders, crystalline boron, amorphous boron and combination both of them were respectively fitted in the synthesis. The raw materials were mixed in a stoichiometric ratio of Mg: B=1:2, ground using agate mortar, packed into stainless steel SS304. The pack was then sintered at temperature of 800°C for 2 hours in air atmosphere. Phase formation of MgB2 polycrystalline in difference of initial boron phase was characterized using XRD and SEM. Referring to the diffraction pattern and microstructure observation, MgB2 polycrystalline was formed, and the formation was effective when using the crystalline Mg and fully amorphous B as the raw materials. The critical temperature of the specimen was evaluated by the cryogenic magnet. The transition temperature of the MgB2 specimen synthesized using crystalline magnesium and full amorphous boron is 42.678 K (ΔTc = 0.877 K).

  11. Black powder in gas pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Sherik, Abdelmounam [Saudi Aramco, Dhahran (Saudi Arabia)

    2009-07-01

    Despite its common occurrence in the gas industry, black powder is a problem that is not well understood across the industry, in terms of its chemical and physical properties, source, formation, prevention or management of its impacts. In order to prevent or effectively manage the impacts of black powder, it is essential to have knowledge of its chemical and physical properties, formation mechanisms and sources. The present paper is divided into three parts. The first part of this paper is a synopsis of published literature. The second part reviews the recent laboratory and field work conducted at Saudi Aramco Research and Development Center to determine the compositions, properties, sources and formation mechanisms of black powder in gas transmission systems. Microhardness, nano-indentation, X-ray Diffraction (XRD), X-ray Fluorescence (XRF) and Scanning Electron Microscopy (SEM) techniques were used to analyze a large number of black powder samples collected from the field. Our findings showed that black powder is generated inside pipelines due to internal corrosion and that the composition of black powder is dependent on the composition of transported gas. The final part presents a summary and brief discussion of various black powder management methods. (author)

  12. Characteristic of nanoparticles generated from different nano-powders by using different dispersion methods

    International Nuclear Information System (INIS)

    Tsai, Chuen-Jinn; Lin, Guan-Yu; Liu, Chun-Nan; He, Chi-En; Chen, Chun-Wan

    2012-01-01

    A standard rotating drum with a modified sampling train (RD), a vortex shaker (VS), and a SSPD (small-scale powder disperser) were used to investigate the emission characteristics of nano-powders, including nano-titanium dioxide (nano-TiO 2 , primary diameter: 21 nm), nano-zinc oxide (nano-ZnO, primary diameter: 30–50 nm), and nano-silicon dioxide (nano-SiO 2 , primary diameter: 10–30 nm). A TSI SMPS (scanning mobility particle sizer), a TSI APS (aerodynamic particle sizer), and a MSP MOUDI (micro-orifice uniform deposit impactor) were used to measure the number and mass distributions of generated particles. Significant differences in specific number and mass concentration or distributions were found among different methods and nano-powders with the most specific number and mass concentration and the smallest particles being generated by the most energetic SSPD, followed by VS and RD. Near uni-modal number or mass distributions were observed for the SSPD while bi-modal number or mass distributions existed for nano-powders except nano-SiO 2 which also exhibited bimodal mass distributions. The 30-min average results showed that the mass median aerodynamic diameter (MMAD) and number median diameter (NMD) of the SSPD ranged 1.1–2.1 μm and 166–261 nm, respectively, for all three nano-powders, which were smaller than those of the VS (MMAD: 3.3–6.0 μm and NMD: 156–462 nm), and the RD (MMAD: 5.2–11.2 μm and NMD: 198–479 nm). For nano-particles (electric mobility diameter < 100 nm), specific mass concentrations were nearly negligible for all three nano-powders and test methods. Specific number concentrations of nano-particles were low for the RD tester but were elevated when more energetic VS and SSPD testers were used. The quantitative size and concentration data obtained in this study is useful to elucidate the field emission and personal exposure data in the future provided that particle loss in the generation system is carefully assessed.

  13. Influence of Starting Powders on Hydroxyapatite Coatings Fabricated by Room Temperature Spraying Method.

    Science.gov (United States)

    Seo, Dong Seok; Lee, Jong Kook; Hwang, Kyu Hong; Hahn, Byung Dong; Yoon, Seog Young

    2015-08-01

    Three types of raw materials were used for the fabrication of hydroxyapatite coatings by using the room temperature spraying method and their influence on the microstructure and in vitro characteristics were investigated. Starting hydroxyapatite powders for coatings on titanium substrate were prepared by a heat treatment at 1100 °C for 2 h of bovine bone, bone ash, and commercial hydroxyapatite powders. The phase compositions and Ca/P ratios of the three hydroxyapatite coatings were similar to those of the raw materials without decomposition or formation of a new phase. All hydroxyapatite coatings showed a honeycomb structure, but their surface microstructures revealed different features in regards to surface morphology and roughness, based on the staring materials. All coatings consisted of nano-sized grains and had dense microstructure. Inferred from in vitro experiments in pure water, all coatings have a good dissolution-resistance and biostability in water.

  14. A three-dimensional polarization domain retrieval method from electron diffraction data

    International Nuclear Information System (INIS)

    Pennington, Robert S.; Koch, Christoph T.

    2015-01-01

    We present an algorithm for retrieving three-dimensional domains of picometer-scale shifts in atomic positions from electron diffraction data, and apply it to simulations of ferroelectric polarization in BaTiO 3 . Our algorithm successfully and correctly retrieves polarization domains in which the Ti atom positions differ by less than 3 pm (0.4% of the unit cell diagonal distance) with 5 and 10 nm depth resolution along the beam direction, and we also retrieve unit cell strain, corresponding to tetragonal-to-cubic unit cell distortions, for 10 nm domains. Experimental applicability is also discussed. - Highlights: • We show a retrieval method for ferroelectric polarization from TEM diffraction data. • Simulated strain and polarization variations along the beam direction are retrieved. • This method can be used for 3D strain and polarization mapping without specimen tilt

  15. Molecular structure determination of cyclooctane by Ab Initio and electron diffraction methods in the gas phase

    International Nuclear Information System (INIS)

    Almeida, Wagner B. de

    2000-01-01

    The determination of the molecular structure of molecules is of fundamental importance in chemistry. X-rays and electron diffraction methods constitute in important tools for the elucidation of the molecular structure of systems in the solid state and gas phase, respectively. The use of quantum mechanical molecular orbital ab initio methods offer an alternative for conformational analysis studies. Comparison between theoretical results and those obtained experimentally in the gas phase can make a significant contribution for an unambiguous determination of the geometrical parameters. In this article the determination for an unambiguous determination of the geometrical parameters. In this article the determination of the molecular structure of the cyclooctane molecule by electron diffraction in the gas phase an initio calculations will be addressed, providing an example of a comparative analysis of theoretical and experimental predictions. (author)

  16. Bulk synthesis of nanocrystalline urania powders by citrate gel-combustion method

    International Nuclear Information System (INIS)

    Sanjay Kumar, D.; Ananthasivan, K.; Venkata Krishnan, R.; Amirthapandian, S.; Dasgupta, Arup

    2016-01-01

    Bulk quantities (60 g) of nanocrystalline (nc) free flowing urania powders with crystallite size ranging from 38 to 252 nm have been synthesized for the first time by the citrate gel combustion method. A systematic study of the influence of the fuel (citric acid) to oxidant (nitrate) ratio (R) on the characteristics of the urania powders has been carried out for the first time. Mixture with an “R” value of 0.25 exhibited a vigorous auto-ignition reaction. This reaction was investigated with Differential Scanning Calorimetry (DSC) and in-situ thermogravimetry coupled with differential thermal analysis and mass spectrometry (TG-DTA-MS). The bulk density, specific surface area, X-ray crystallite size, residual carbon and size distribution of particles of this powder were unique. Microscopic and microstructural investigation of selected samples revealed the presence of nanocrystals with irregular exfoliated morphology; their Electron Energy Loss Spectra testified the covalency of the U–O bond. - Highlights: • Bulk quantities of nanocrystalline urania were prepared for the first time using citrate gel combustion method. • Volume combustion was observed in mixtures with fuel to nitrate ratio (R) 0.25. • The value of R was found to significantly influence the characteristics of the final product. • Typical exfoliated microstructure and nanopores were observed. • Established correlation between particle size distribution and bulk density, X-ray crystallite size and lattice strain. • Relationship between fuel to nitrate (R) mole ratio and physical characteristics of powders were also established.

  17. A novel method to remove the background from x-ray diffraction signal

    DEFF Research Database (Denmark)

    Zheng, Yi; Speller, Robert; Griffiths, Jennifer

    2018-01-01

    The first step that is required to extract the correct information from a two-dimensional (2D) diffraction signature is to remove the background accurately. However, direct background subtraction inevitably overcorrects the signal as it does not take into account the attenuation by the sample. Ot...... proposes a novel method that combines peak fitting and experimental results to estimate the background for 2D XRD signals....

  18. Determination of metal impurities in MOX powder by direct current arc atomic emission spectroscopy. Application of standard addition method for direct analysis of powder sample

    International Nuclear Information System (INIS)

    Furuse, Takahiro; Taguchi, Shigeo; Kuno, Takehiko; Surugaya, Naoki

    2016-12-01

    Metal impurities in MOX powder obtained from uranium and plutonium recovered from reprocessing process of spent nuclear fuel have to be determined for its characterization. Direct current arc atomic emission spectroscopy (DCA-AES) is one of the useful methods for direct analysis of powder sample without dissolving the analyte into aqueous solution. However, the selection of standard material, which can overcome concerns such as matrix matching, is quite important to create adequate calibration curves for DCA-AES. In this study, we apply standard addition method using the certified U_3O_8 containing known amounts of metal impurities to avoid the matrix problems. The proposed method provides good results for determination of Fe, Cr and Ni contained in MOX samples at a significant quantity level. (author)

  19. A new method of Debye-Scherrer pattern integration on two-dimensional detectors, demonstrated for the new structure powder diffractometer (SPODI) at the FRM-II in Garching

    CERN Document Server

    Elf, F; Artus, G R J; Roth, S

    2002-01-01

    The expected diffraction patterns of the new powder diffractometer SPODI, currently under construction at the FRM-II in Garching, will be smeared Debye-Scherrer rings as depicted by Monte Carlo (MC) simulations. To overcome this disadvantage, a concept based on the combination of MC simulations and empirical approximation methods is developed to reverse the smearing by deconvolution and then summing up along the rings, including corrections for different arc lengths, resulting in conventional one-dimensional diffraction patterns suitable for Rietveld-refinement programs without further processing. (orig.)

  20. Synthesis of alumina powder with seeds by Pechini Method using O2 as calcination atmosphere

    International Nuclear Information System (INIS)

    Salem, R.E.P.; Guilherme, K.A.; Chinelatto, A.S.A.; Chinelatto, A. L.

    2012-01-01

    Alumina is a very investigated material due to its excellent refractory characteristics and mechanical properties. Its alpha phase, the most stable one, has a formation temperature of about 1200 ° C. Due to its high temperature of formation, many researches have been trying to reduce it through addition of seeds of alpha phase in chemical processes of synthesis. This work aims to synthesize ultrafine powders of alpha-alumina by the Pechini method with seeding, and using an O 2 atmosphere in the pre-calcination (500 ° C) and calcination (1000 ° C and 1100° C) steps. The resulting powders were characterized through X-ray diffractometry, infrared spectroscopy and scanning electron microscopy. The results were compared with samples calcined on ai. It was verified that the presence of oxygen in the calcination atmosphere favored the elimination of residual carbon from the precursor powders, forthcoming from the great amount of organic material used on the synthesis, modifying its morphology and favoring reduction of particle size. (author)

  1. Effect of Graphene Nanoplatelets addition on mechanical properties of pure aluminum using a semi-powder method

    Directory of Open Access Journals (Sweden)

    Muhammad Rashad

    2014-04-01

    Full Text Available In recent years, graphene has attracted considerable research interest in all fields of science due to its unique properties. Its excellent mechanical properties lead it to be used in nano-composites for strength enhancement. This paper reports an Aluminum–Graphene Nanoplatelets (Al/GNPs composite using a semi-powder method followed by hot extrusion. The effect of GNP nano-particle integration on tensile, compressive and hardness response of Al is investigated in this paper. It is demonstrated that 0.3 wt% Graphene Nanoplatelets distributed homogeneously in the matrix aluminum act as an effective reinforcing filler to prevent deformation. Compared to monolithic aluminum (in tension, Al–0.3 wt% GNPs composite exhibited higher 0.2% yield strength (+14.7%, ultimate tensile strength (+11.1% and lower failure strain (−40.6%. Surprisingly, compared to monolithic Al (in compression, Al–0.3 wt% GNPs composite exhibited same 0.2% compressive yield strength and lower ultimate compression strength (−7.8%, and lower failure strain (−20.2%. The Al–0.3 wt% GNPs composite exhibited higher Vickers hardness compared to monolithic aluminum (+11.8%. Scanning electron microscopy (SEM, Energy-Dispersive X-ray Spectroscopy (EDS and X-ray diffraction (XRD were used to investigate the surface morphology, elemental percentage composition, and phase analysis, respectively.

  2. Influence of Process Control Agent on Characterization and Structure of Micron Chitosan Powders Prepared by Ball Milling Method

    Directory of Open Access Journals (Sweden)

    ZHANG Chuan-jie

    2016-12-01

    Full Text Available With ethyl alcohol or distilled water as process control agent (PCA, micron chitosan powder was prepared by ball milling method. The yield rate, particle size distribution, micro morphology, viscosity average molecular mass, chemical and crystal structures, and thermal properties of these different micron chitosan powders were measured. The results indicate that the yield rate of micron chitosan powders prepared with ethyl alcohol as PCA increases significantly, and improves to 94.7% from 25% while the amount of ethyl alcohol is 0.75mL/g. The particle size distribution of micron chitosan powder prepared with ethyl alcohol as PCA is concentrated, while the D50 and D90 in size are 824nm and 1629nm respectively. Chitosan do not react with ethyl alcohol used as PCA, but the viscosity average molecular mass of prepared micron chitosan powder decreases by 23%, the crystal structures are destroyed slightly, and its thermal stability is slightly weakened.

  3. Effect of heat absorbing powder addition on cell morphology of porous titanium composite manufactured by reactive precursor method

    International Nuclear Information System (INIS)

    Kobashi, Makoto; Kamiya, Yoshinori; Kanetake, Naoyuki

    2012-01-01

    Open-cell structured porous titanium/ceramics composite was synthesized by a reactive precursor method using titanium and boron carbide (B 4 C) as reactant powders. Pore morphology was controlled by adding heat absorbing powder (titanium diboride: TiB 2 ) in the Ti+B 4 C blended powder. The effects of molar blending ratio of titanium and B 4 C and the amount of heat absorbing powder addition on the cell morphology (either open or closed) were investigated. Fine and homogeneous open-cell structure was achieved by adding appropriate amount of heat absorbing agent powder (>15 vol%), and the relative density of the specimen after the reaction became closer to that of the precursor by increasing TiB 2 volume fraction. When the volume fraction of TiB 2 addition was 20%, the open-cell fraction was maintained as 1.0 regardless of the relative density of the precursor.

  4. Nonuniform fast Fourier transform method for numerical diffraction simulation on tilted planes.

    Science.gov (United States)

    Xiao, Yu; Tang, Xiahui; Qin, Yingxiong; Peng, Hao; Wang, Wei; Zhong, Lijing

    2016-10-01

    The method, based on the rotation of the angular spectrum in the frequency domain, is generally used for the diffraction simulation between the tilted planes. Due to the rotation of the angular spectrum, the interval between the sampling points in the Fourier domain is not even. For the conventional fast Fourier transform (FFT)-based methods, a spectrum interpolation is needed to get the approximate sampling value on the equidistant sampling points. However, due to the numerical error caused by the spectrum interpolation, the calculation accuracy degrades very quickly as the rotation angle increases. Here, the diffraction propagation between the tilted planes is transformed into a problem about the discrete Fourier transform on the uneven sampling points, which can be evaluated effectively and precisely through the nonuniform fast Fourier transform method (NUFFT). The most important advantage of this method is that the conventional spectrum interpolation is avoided and the high calculation accuracy can be guaranteed for different rotation angles, even when the rotation angle is close to π/2. Also, its calculation efficiency is comparable with that of the conventional FFT-based methods. Numerical examples as well as a discussion about the calculation accuracy and the sampling method are presented.

  5. Influence of Ultrafine 2CaO·SiO₂ Powder on Hydration Properties of Reactive Powder Concrete.

    Science.gov (United States)

    Sun, Hongfang; Li, Zishanshan; Memon, Shazim Ali; Zhang, Qiwu; Wang, Yaocheng; Liu, Bing; Xu, Weiting; Xing, Feng

    2015-09-17

    In this research, we assessed the influence of an ultrafine 2CaO·SiO₂ powder on the hydration properties of a reactive powder concrete system. The ultrafine powder was manufactured through chemical combustion method. The morphology of ultrafine powder and the development of hydration products in the cement paste prepared with ultrafine powder were investigated by scanning electron microscopy (SEM), mineralogical composition were determined by X-ray diffraction, while the heat release characteristics up to the age of 3 days were investigated by calorimetry. Moreover, the properties of cementitious system in fresh and hardened state (setting time, drying shrinkage, and compressive strength) with 5% ordinary Portland cement replaced by ultrafine powder were evaluated. From SEM micrographs, the particle size of ultrafine powder was found to be up to several hundred nanometers. The hydration product started formulating at the age of 3 days due to slow reacting nature of belitic 2CaO·SiO₂. The initial and final setting times were prolonged and no significant difference in drying shrinkage was observed when 5% ordinary Portland cement was replaced by ultrafine powder. Moreover, in comparison to control reactive powder concrete, the reactive powder concrete containing ultrafine powder showed improvement in compressive strength at and above 7 days of testing. Based on above, it can be concluded that the manufactured ultrafine 2CaO·SiO₂ powder has the potential to improve the performance of a reactive powder cementitious system.

  6. Influence of Ultrafine 2CaO·SiO2 Powder on Hydration Properties of Reactive Powder Concrete

    Directory of Open Access Journals (Sweden)

    Hongfang Sun

    2015-09-01

    Full Text Available In this research, we assessed the influence of an ultrafine 2CaO·SiO2 powder on the hydration properties of a reactive powder concrete system. The ultrafine powder was manufactured through chemical combustion method. The morphology of ultrafine powder and the development of hydration products in the cement paste prepared with ultrafine powder were investigated by scanning electron microscopy (SEM, mineralogical composition were determined by X-ray diffraction, while the heat release characteristics up to the age of 3 days were investigated by calorimetry. Moreover, the properties of cementitious system in fresh and hardened state (setting time, drying shrinkage, and compressive strength with 5% ordinary Portland cement replaced by ultrafine powder were evaluated. From SEM micrographs, the particle size of ultrafine powder was found to be up to several hundred nanometers. The hydration product started formulating at the age of 3 days due to slow reacting nature of belitic 2CaO·SiO2. The initial and final setting times were prolonged and no significant difference in drying shrinkage was observed when 5% ordinary Portland cement was replaced by ultrafine powder. Moreover, in comparison to control reactive powder concrete, the reactive powder concrete containing ultrafine powder showed improvement in compressive strength at and above 7 days of testing. Based on above, it can be concluded that the manufactured ultrafine 2CaO·SiO2 powder has the potential to improve the performance of a reactive powder cementitious system.

  7. Measurements of Residual Stresses In Cold-Rolled 304 Stainless Steel Plates Using X-Ray Diffraction with Rietveld Refinement Method

    International Nuclear Information System (INIS)

    Parikin; Killen, P; Rafterry, A.

    2009-01-01

    The determination of the residual stresses using X-ray powder diffraction in a series of cold-rolled 304 stainless steel plates, deforming 0, 34, 84, 152, 158, 175 and 196 % reduction in thickness has been carried out. The diffraction data were analyzed using the Rietveld structure refinement method. The analysis shows that for all specimens, the martensite particles are closely in compression and the austenite matrix is in tension. Both the martensite and austenite, for a sample reducing 34% in thickness (containing of about 1% martensite phase) the average lattice strains are anisotropic and decrease approximately exponential with an increase in the corresponding percent reduction (essentially phase content). It is shown that this feature can be qualitatively understood by taking into consideration the thermal expansion mismatch between the martensite and austenite grains. Also, for all cold-rolled stainless steel specimens, the diffraction peaks are broader than the unrolled one (instrumental resolution), indicating that the strains in these specimens are inhomogeneous. From an analysis of the refined peak shape parameters, the average root-mean square strain, which describes the distribution of the inhomogeneous strain field, was predicted. The average residual stresses in cold-rolled 304 stainless steel plates showed a combination effect of hydrostatic stresses of the martensite particles and the austenite matrix. (author)

  8. Quantitative firing transformations of a triaxial ceramic by X-ray diffraction methods

    International Nuclear Information System (INIS)

    Conconi, M.S.; Gauna, M.R.; Serra, M.F.; Suarez, G.; Aglietti, E.F.; Rendtorff, N.M.

    2014-01-01

    The firing transformations of traditional (clay based) ceramics are of technological and archaeological interest, and are usually reported qualitatively or semi quantitatively. These kinds of systems present an important complexity, especially for X-ray diffraction techniques, due to the presence of fully crystalline, low crystalline and amorphous phases. In this article we present the results of a qualitative and quantitative X-ray diffraction Rietveld analysis of the fully crystalline (kaolinite, quartz, cristobalite, feldspars and/or mullite), the low crystalline (metakaolinite and/or spinel type pre-mullite) and glassy phases evolution of a triaxial (clay-quartz-feldspar) ceramic fired in a wide temperature range between 900 and 1300 deg C. The employed methodology to determine low crystalline and glassy phase abundances is based in a combination of the internal standard method and the use of a nanocrystalline model where the long-range order is lost, respectively. A preliminary sintering characterization was carried out by contraction, density and porosity evolution with the firing temperature. Simultaneous thermo-gravimetric and differential thermal analysis was carried out to elucidate the actual temperature at which the chemical changes occur. Finally, the quantitative analysis based on the Rietveld refinement of the X-ray diffraction patterns was performed. The kaolinite decomposition into metakaolinite was determined quantitatively; the intermediate (980 deg C) spinel type alumino-silicate formation was also quantified; the incongruent fusion of the potash feldspar was observed and quantified together with the final mullitization and the amorphous (glassy) phase formation.The methodology used to analyze the X-ray diffraction patterns proved to be suitable to evaluate quantitatively the thermal transformations that occur in a complex system like the triaxial ceramics. The evaluated phases can be easily correlated with the processing variables and materials

  9. Quantitative firing transformations of a triaxial ceramic by X-ray diffraction methods

    Energy Technology Data Exchange (ETDEWEB)

    Conconi, M.S.; Gauna, M.R.; Serra, M.F. [Centro de Tecnologia de Recursos Minerales y Ceramica (CETMIC), Buenos Aires (Argentina); Suarez, G.; Aglietti, E.F.; Rendtorff, N.M., E-mail: rendtorff@cetmic.unlp.edu.ar [Universidad Nacional de La Plata (UNLP), Buenos Aires (Argentina). Fac. de Ciencias Exactas. Dept. de Quimica

    2014-10-15

    The firing transformations of traditional (clay based) ceramics are of technological and archaeological interest, and are usually reported qualitatively or semi quantitatively. These kinds of systems present an important complexity, especially for X-ray diffraction techniques, due to the presence of fully crystalline, low crystalline and amorphous phases. In this article we present the results of a qualitative and quantitative X-ray diffraction Rietveld analysis of the fully crystalline (kaolinite, quartz, cristobalite, feldspars and/or mullite), the low crystalline (metakaolinite and/or spinel type pre-mullite) and glassy phases evolution of a triaxial (clay-quartz-feldspar) ceramic fired in a wide temperature range between 900 and 1300 deg C. The employed methodology to determine low crystalline and glassy phase abundances is based in a combination of the internal standard method and the use of a nanocrystalline model where the long-range order is lost, respectively. A preliminary sintering characterization was carried out by contraction, density and porosity evolution with the firing temperature. Simultaneous thermo-gravimetric and differential thermal analysis was carried out to elucidate the actual temperature at which the chemical changes occur. Finally, the quantitative analysis based on the Rietveld refinement of the X-ray diffraction patterns was performed. The kaolinite decomposition into metakaolinite was determined quantitatively; the intermediate (980 deg C) spinel type alumino-silicate formation was also quantified; the incongruent fusion of the potash feldspar was observed and quantified together with the final mullitization and the amorphous (glassy) phase formation.The methodology used to analyze the X-ray diffraction patterns proved to be suitable to evaluate quantitatively the thermal transformations that occur in a complex system like the triaxial ceramics. The evaluated phases can be easily correlated with the processing variables and materials

  10. Quantitative firing transformations of a triaxial ceramic by X-ray diffraction methods

    Directory of Open Access Journals (Sweden)

    M. S. Conconi

    2014-12-01

    Full Text Available The firing transformations of traditional (clay based ceramics are of technological and archeological interest, and are usually reported qualitatively or semiquantitatively. These kinds of systems present an important complexity, especially for X-ray diffraction techniques, due to the presence of fully crystalline, low crystalline and amorphous phases. In this article we present the results of a qualitative and quantitative X-ray diffraction Rietveld analysis of the fully crystalline (kaolinite, quartz, cristobalite, feldspars and/or mullite, the low crystalline (metakaolinite and/or spinel type pre-mullite and glassy phases evolution of a triaxial (clay-quartz-feldspar ceramic fired in a wide temperature range between 900 and 1300 ºC. The employed methodology to determine low crystalline and glassy phase abundances is based in a combination of the internal standard method and the use of a nanocrystalline model where the long-range order is lost, respectively. A preliminary sintering characterization was carried out by contraction, density and porosity evolution with the firing temperature. Simultaneous thermo-gravimetric and differential thermal analysis was carried out to elucidate the actual temperature at which the chemical changes occur. Finally, the quantitative analysis based on the Rietveld refinement of the X-ray diffraction patterns was performed. The kaolinite decomposition into metakaolinite was determined quantitatively; the intermediate (980 ºC spinel type alumino-silicate formation was also quantified; the incongruent fusion of the potash feldspar was observed and quantified together with the final mullitization and the amorphous (glassy phase formation.The methodology used to analyze the X-ray diffraction patterns proved to be suitable to evaluate quantitatively the thermal transformations that occur in a complex system like the triaxial ceramics. The evaluated phases can be easily correlated with the processing variables and

  11. Sintering by infiltration of loose mixture of powders, a method for metal matrix composite elaboration

    International Nuclear Information System (INIS)

    Constantinescu, V.; Orban, R.; Colan, H.

    1993-01-01

    Starting from the observation that Sintering by Infiltration of Loose Mixture of Powders confers large possibilities for both complex shaped and of large dimensions Particulate Reinforced Metal Matrix Composite components elaboration, its mechanism comparative with those of the classical melt infiltration was investigated. Appropriate measures in order to prevent an excessive hydrostatic flow of the melt and, consequently, reinforcement particle dispersion, as well as to promote wetting in both infiltration and liquid phase sintering stages of the process were established as necessary. Some experimental results in the method application to the fusion tungsten carbide and diamond reinforced metal matrix composite elaboration are, also, presented. (orig.)

  12. Mixed-linker UiO-66: structure-property relationships revealed by a combination of high-resolution powder X-ray diffraction and density functional theory calculations.

    Science.gov (United States)

    Taddei, Marco; Tiana, Davide; Casati, Nicola; van Bokhoven, Jeroen A; Smit, Berend; Ranocchiari, Marco

    2017-01-04

    The use of mixed-linker metal-organic frameworks (MIXMOFs) is one of the most effective strategies to modulate the physical-chemical properties of MOFs without affecting the overall crystal structure. In many instances, MIXMOFs have been recognized as solid solutions, with random distribution of ligands, in agreement with the empirical rule known as Vegard's law. In this work, we have undertaken a study combining high-resolution powder X-ray diffraction (HR-PXRD) and density functional theory (DFT) calculations with the aim of understanding the reasons why UiO-66-based amino- and bromo-functionalized MIXMOFs (MIXUiO-66) undergo cell expansion obeying Vegard's law and how this behaviour is related to their physical-chemical properties. DFT calculations predict that the unit cell in amino-functionalized UiO-66 experiences only minor expansion as a result of steric effects, whereas major modification to the electronic features of the framework leads to weaker metal-linker interaction and consequently to the loss of stability at higher degrees of functionalization. For bromo-functionalized UiO-66, steric repulsion due to the size of bromine yields a large cell expansion, but the electronic features remain very similar to pristine UiO-66, preserving the stability of the framework upon functionalization. MIXUiO-66 obtained by either direct synthesis or by post-synthetic exchange shows Vegard-like behaviour, suggesting that both preparation methods yield solid solutions, but the thermal stability and the textural properties of the post-synthetic exchanged materials do not display a clear dependence on the chemical composition, as observed for the MOFs obtained by direct synthesis.

  13. Simultaneous Determination of Florfenicol and Diclazuril in Compound Powder by RP-HPLC-UV Method

    Directory of Open Access Journals (Sweden)

    Leilei Guo

    2014-01-01

    Full Text Available A RP-HPLC-UV method was developed and validated for simultaneous determination of florfenicol and diclazuril in compound powder. The separation involved using a SinoChoom ODS-BP C18 (5 μm, 4.6 mm × 250 mm analytical column. The mobile phase was a mixture of acetonitrile-0.2% phosphoric acid (pH was adjusted to 3.0 with triethylamine. The ratio of acetonitrile and 0.2% phosphoric acid in the mobile phase was 60 : 40 (v/v from 0 minutes to 6 minutes and 70 : 30 (v/v from 6.1 minutes to 15 minutes. The flow rate was 1 mL/min. The temperature of the analytical column was maintained at 30°C. The detection was monitored at 225 nm and 277 nm for florfenicol and diclazuril, respectively. The excipients in the compound powder did not interfere with the drug peaks. The calibration curves of florfenicol and diclazuril were fairly linear over the concentration ranges between 50.0–500.0 μg/mL (r=0.9995 and 10.0–100.0 μg/mL (r=0.9992, respectively. The RSD of both the intraday and interday variations was below 2.1% for florfenicol and diclazuril. The method was successfully validated according to International Conference on Harmonisation and proved to be suitable for the simultaneous determination of florfenicol and diclazuril in compound powder.

  14. Structural study of CaMn{sub 1−x}Mo{sub x}O{sub 3} (0.08 ≤ x ≤ 0.12) system by neutron powder diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Supelano, G.I., E-mail: ivan.supelano@uptc.edu.co [Grupo Física de Materiales, Escuela de Física, Universidad Pedagógica y Tecnológica de Colombia, Tunja (Colombia); Parra Vargas, C.A.; Barón-González, A.J. [Grupo Física de Materiales, Escuela de Física, Universidad Pedagógica y Tecnológica de Colombia, Tunja (Colombia); Sarmiento Santos, A. [Grupo Superficies Electroquímica y Corrosión, Escuela de Física, Universidad Pedagógica y Tecnológica de Colombia, Tunja (Colombia); Frontera, C. [Institut de Ciència de Materials de Barcelona, CSIC, Campus Universitari de Bellaterra, E-08193, Bellaterra, Barcelona (Spain)

    2016-08-15

    Neutron powder diffraction experiments and magnetic measurements in polycrystalline CaMn{sub 1−x}Mo{sub x}O{sub 3} (x = 0.08, 0.10, 0.12) point towards a possible charge and orbital order in this system. The analysis of structural and magnetic data show that the samples present structural phase transformation from Pnma to P2{sub 1}/m space group and the system has a C-type antiferromagnetic configuration at low temperature. A detailed analysis of the bond distances signals a small Jahn-Teller distortion of only one (x = 0.08) or of the two Mn ions (x = 0.10, 0.12). We identify the partially occupied e{sub g} orbitals and this explains the C-type magnetic structure. - Highlights: • CaMn{sub 1−x}Mo{sub x}O{sub 3} (x = 0.08, 0.10, 0.12) is investigated by neutron powder diffraction. • Analysis of individual Mn-O distances demonstrates the apparition of orbital order. • By symmetry analysis, we find that the low temperature magnetic structure is C-type. • Magnetic interactions foreseen by the orbital order explain the magnetic structure.

  15. Structural properties of a family of hydrogen-bonded co-crystals formed between gemfibrozil and hydroxy derivatives of t-butylamine, determined directly from powder X-ray diffraction data

    International Nuclear Information System (INIS)

    Cheung, Eugene Y.; David, Sarah E.; Harris, Kenneth D.M.; Conway, Barbara R.; Timmins, Peter

    2007-01-01

    We report the formation and structural properties of co-crystals containing gemfibrozil and hydroxy derivatives of t-butylamine H 2 NC(CH 3 ) 3- n (CH 2 OH) n , with n=0, 1, 2 and 3. In each case, a 1:1 co-crystal is formed, with transfer of a proton from the carboxylic acid group of gemfibrozil to the amino group of the t-butylamine derivative. All of the co-crystal materials prepared are polycrystalline powders, and do not contain single crystals of suitable size and/or quality for single crystal X-ray diffraction studies. Structure determination of these materials has been carried out directly from powder X-ray diffraction data, using the direct-space Genetic Algorithm technique for structure solution followed by Rietveld refinement. The structural chemistry of this series of co-crystal materials reveals well-defined structural trends within the first three members of the family (n=0, 1, 2), but significantly contrasting structural properties for the member with n=3. - Graphical abstract: Structural properties of a family of co-crystals containing gemfibrozil and hydroxy derivatives of t-butylamine are discussed and rationalized

  16. X-ray diffraction and Moessbauer studies on superparamagnetic nickel ferrite (NiFe{sub 2}O{sub 4}) obtained by the proteic sol–gel method

    Energy Technology Data Exchange (ETDEWEB)

    Nogueira, N.A.S. [Departamento de Engenharia Metalúrgica e de Materiais, Centro de Tecnologia, Campus do Pici, Universidade Federal do Ceará – UFC, 60455-760 Fortaleza, CE (Brazil); Utuni, V.H.S.; Silva, Y.C. [Departamento de Física, Universidade Federal do Ceará – UFC, Campus do Pici, 60440-970 Fortaleza, CE (Brazil); Kiyohara, P.K. [Instituto de Física, Universidade de São Paulo – USP, 05315-970 São Paulo, SP (Brazil); Vasconcelos, I.F. [Departamento de Engenharia Metalúrgica e de Materiais, Centro de Tecnologia, Campus do Pici, Universidade Federal do Ceará – UFC, 60455-760 Fortaleza, CE (Brazil); Miranda, M.A.R., E-mail: marcus.a.r.miranda@gmail.com [Departamento de Física, Universidade Federal do Ceará – UFC, Campus do Pici, 60440-970 Fortaleza, CE (Brazil); Sasaki, J.M. [Departamento de Física, Universidade Federal do Ceará – UFC, Campus do Pici, 60440-970 Fortaleza, CE (Brazil)

    2015-08-01

    Nickel ferrite (NiFe{sub 2}O{sub 4}) nanoparticles were synthesized by the proteic sol–gel method at synthesis temperature of 250 °C, 300 °C and 400 °C, with the objective of obtaining superparamagnetic nanoparticles. Thermogravimetric analysis (TGA) and temperature-programed oxidation (TPO) presented peaks around 290 °C indicating that nickel ferrite was forming at this temperature. X-ray powder diffraction (XRPD) confirmed that the polycrystalline sample was single phased NiFe{sub 2}O{sub 4} with space group Fd3m. Scherrer equation applied to the diffraction patterns and transmission electron microscopy (TEM) images showed that the size of the nanoparticles ranged from 9 nm to 13 nm. TEM images also revealed that the nanoparticles were agglomerated, which was supported by the low values of surface area provided by the Brunauer-Emmet-Teller (BET) method. Moessbauer spectroscopy presented spectra composed of a superposition of three components: a sextet, a doublet and a broad singlet pattern. The sample synthetized at 300 °C had the most pronounced doublet pattern characteristic of superparamagnetic nanoparticles. In conclusion, this method was partially successful in obtaining superparamagnetic nickel ferrite nanoparticles, in which the synthetized samples were a mixture of nanoparticles with blocking temperature above and below room temperature. Magnetization curves revealed a small hysteresis, supporting the Moessbauer results. The sample with the higher concentration of superparamagnetic nanoparticles being the one synthetized at 300 °C. - Highlights: • Superparamagnetic nickel ferrite nanoparticles were grown by the proteic sol–gel method. • The proteic sol–gel method provided superparamagnetic nickel ferrite nanoparticles with sizes in the range of 9–13 nm. • Nickel ferrite nanoparticles were prepared at temperatures as low as 250 °C. • The nickel ferrite nanoparticles were studied by x-ray diffraction and Moessbauer.

  17. Application of the Rietveld method in powders of strontium-doped lanthanum manganite calcined in different temperatures

    International Nuclear Information System (INIS)

    Chiba, R.; Vargas, R.A.; Martinez, L.G.; Andreoli, M.; Seo, E.S.M.

    2010-01-01

    The strontium-doped lanthanum manganite (LSM) is a ceramic material used as cathode in device called High Temperature Solid Oxide Fuel Cell. In this work, the LSM was synthesized by the citrate technique with the objective to get powders without the formation of secondary phases, such as lanthanum oxide and the lanthanum hydroxide, harmful for the functional performance of the device. The definitive calcination temperatures had been 700, 900 and 1100 deg C, due the decomposition of the polymeric precursors to present stabilization from 480 deg C. The analysis by X-ray diffraction of the calcined powders in different temperatures shows the formation only of phase LSM of hexagonal crystalline structure, type pseudo-perovskite. Using the refinement of Rietveld was determined the parameters and volumes of unity cells, atomic positions and occupations. These results confirm that the chemical compositions obtained are similar to the nominal. (author)

  18. Fundamentals of powder metallurgy

    International Nuclear Information System (INIS)

    Khan, I.H.; Qureshi, K.A.; Minhas, J.I.

    1988-01-01

    This book is being presented to introduce the fundamentals of technology of powder metallurgy. An attempt has been made to present an overall view of powder metallurgy technology in the first chapter, whereas chapter 2 to 8 deal with the production of metal powders. The basic commercial methods of powder production are briefly described with illustrations. Chapter 9 to 12 describes briefly metal powder characteristics and principles of testing, mixing, blending, conditioning, compaction and sintering. (orig./A.B.)

  19. A convenient method to prepare emulsified polyacrylate nanoparticles from powders [corrected] for drug delivery applications.

    Science.gov (United States)

    Garay-Jimenez, Julio C; Turos, Edward

    2011-08-01

    We describe a method to obtain purified, polyacrylate nanoparticles in a homogeneous powdered form that can be readily reconstituted in aqueous media for in vivo applications. Polyacrylate-based nanoparticles can be easily prepared by emulsion polymerization using a 7:3 mixture of butyl acrylate and styrene in water containing sodium dodecyl sulfate as a surfactant and potassium persulfate as a water-soluble radical initiator. The resulting emulsions contain nanoparticles measuring 40-50 nm in diameter with uniform morphology, and can be purified by centrifugation and dialysis to remove larger coagulants as well as residual surfactant and monomers associated with toxicity. These purified emulsions can be lyophilized in the presence of maltose (a non-toxic cryoprotectant) to provide a homogeneous dried powder, which can be reconstituted as an emulsion by addition of an aqueous diluent. Dynamic light scattering and microbiological experiments were carried out on the reconstituted nanoparticles. This procedure allows for ready preparation of nanoparticle emulsions for drug delivery applications. Copyright © 2011 Elsevier Ltd. All rights reserved.

  20. Analysis of macro and micro residual stresses in functionally graded materials by diffraction methods

    CERN Document Server

    Dantz, D; Reimers, W

    1999-01-01

    The residual stress state in microwave sintered metal-ceramic functionally graded materials (FGM) consisting of 8Y-ZrO/sub 2//Ni and 8Y-ZrO/sub 2//NiCr8020, respectively, was analysed by non- destructive diffraction methods. In $9 order to get knowledge of the complete residual stress state in the near surface region as well as in the interior of the material, complementary methods were applied. Whereas the surface was characterised by X-ray techniques using $9 conventional sources, the stresses within the bulk of the material were investigated by means of high energy synchrotron radiation. The stress state was found to obey the differences in the coefficients of thermal expansion $9 (micro-stresses) on the one hand and the inhomogeneous cooling conditions (macrostresses) on the other hand. (7 refs).

  1. Electron backscatter diffraction as a useful method for alloys microstructure characterization

    Energy Technology Data Exchange (ETDEWEB)

    Klimek, Leszek; Pietrzyk, Bozena

    2004-11-17

    Microstructure examination of cast Co-Cr-Mo alloy is presented in this paper. The surface morphology and chemical composition of the alloy were investigated by means of scanning electron microscopy (SEM) and energy dispersive X-ray microanalysis (EDX). An identification of alloy phases was carried out using electron backscatter diffraction (EBSD). Two different kinds of precipitates in metallic matrix were found. They were identified as MC and M{sub 23}C{sub 6} type of carbides in Co-lattice solid solution. The advantages and limits of the EBSD method are described. It is presented that EBSD, as excellent tool for phase identification, is a valuable supplementary method for materials research.

  2. Electron Paramagnetic Resonance and X-ray Diffraction of Boron- and Phosphorus-Doped Nanodiamonds

    Science.gov (United States)

    Binh, Nguyen Thi Thanh; Dolmatov, V. Yu.; Lapchuk, N. M.; Shymanski, V. I.

    2017-11-01

    Powders of boron- and phosphorus-doped detonation nanodiamonds and sintered pellets of non-doped nanodiamond powders were studied using electron paramagnetic resonance and x-ray diffraction. Doping of detonation nanodiamond crystals with boron and phosphorus was demonstrated to be possible. These methods could be used to diagnose diamond nanocrystals doped during shock-wave synthesis.

  3. Interactions from diffraction data: historical and comprehensive overview of simulation assisted methods

    International Nuclear Information System (INIS)

    Toth, Gergely

    2007-01-01

    A large part of statistical mechanics is concerned with the determination of condensed matter structure on the basis of known microscopic interactions. An increasing emphasis has been put on the opposite situation in the last decades as well, where structural data, e.g. pair-distance statistics, are known from diffraction experiments, and one looks for the corresponding interaction functions. The solution of this inverse problem was searched for within the integral equation theories of condensed matter in the early investigations, but before long computer simulation assisted methods were suggested. The interest in this field showed an increasing trend after some attempts appeared in the late 1980s. Several methods were published in the 1990s, and one-two methods appear annually nowadays. In this paper a comprehensive and historical overview is given on the solution of the inverse problem with simulation assisted methods. Emphasis is put on the theoretical grounds of the methods, on the choice of possible input structural functions, on the numerically local or global schemes of the potential modifications, on some advantages and limits of the different methods and on the scientific impact of the methods

  4. An extended diffraction tomography method for quantifying structural damage using numerical Green's functions.

    Science.gov (United States)

    Chan, Eugene; Rose, L R Francis; Wang, Chun H

    2015-05-01

    Existing damage imaging algorithms for detecting and quantifying structural defects, particularly those based on diffraction tomography, assume far-field conditions for the scattered field data. This paper presents a major extension of diffraction tomography that can overcome this limitation and utilises a near-field multi-static data matrix as the input data. This new algorithm, which employs numerical solutions of the dynamic Green's functions, makes it possible to quantitatively image laminar damage even in complex structures for which the dynamic Green's functions are not available analytically. To validate this new method, the numerical Green's functions and the multi-static data matrix for laminar damage in flat and stiffened isotropic plates are first determined using finite element models. Next, these results are time-gated to remove boundary reflections, followed by discrete Fourier transform to obtain the amplitude and phase information for both the baseline (damage-free) and the scattered wave fields. Using these computationally generated results and experimental verification, it is shown that the new imaging algorithm is capable of accurately determining the damage geometry, size and severity for a variety of damage sizes and shapes, including multi-site damage. Some aspects of minimal sensors requirement pertinent to image quality and practical implementation are also briefly discussed. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Magnetic separation as a method to assist mineralogical characterization of rocks by X-ray diffraction

    International Nuclear Information System (INIS)

    Silva, Amanda Luzia da; Oliveira, Arno Heeren de; Fernandes, Maria Lourdes Souza

    2013-01-01

    The X-ray diffraction (XRD) corresponds to one of the main techniques for characterization of structures in crystalline materials widely used in the identification of minerals in samples of geological materials such as rocks. However, the large number of mineral phases present in a rock sample can generate excess peaks in the diffractogram, and it can promote overlapping peaks and induce erroneous identification. The purpose of this study was to perform magnetic separation of minerals from rock samples in order to enable the identification of the minerals by XRD. For this magnetic separation, two samples of rock were selected: a sample of high silica content and a sample with low silica content. The magnetic separation of minerals from each sample was performed using the magnetic separator isodynamic Frantz. Posteriorly, the fractions obtained in magnetic separations were analyzed by XRD. In the sample with high silica content, it was obtained a fraction where was identified the accessory mineral epidote, which had not been identified in the total sample diffractogram. In the sample with low silica content, the magnetic separation into several mineral fractions made possible to obtain diffraction patterns with fewer peaks and peaks with higher relative intensities, which allowed its mineralogical characterization. The results showed that the mineral separation by the magnetic separator Frantz made the identification of accessory minerals by XRD and the characterization of samples which have many mineral phases possible, which proves that magnetic separation by Frantz is a method which can assist analyses by XRD. (author)

  6. Magnetic separation as a method to assist mineralogical characterization of rocks by X-ray diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Amanda Luzia da; Oliveira, Arno Heeren de; Fernandes, Maria Lourdes Souza, E-mail: amanda@igc.ufmg.br, E-mail: heeren@nuclear.ufmg.br, E-mail: amanda@igc.ufmg.br, E-mail: lurdesfernandes@ufmg.br [Universidade Federal de Minas Gerais (UFMG), Belo Horionte, MG (Brazil)

    2013-07-01

    The X-ray diffraction (XRD) corresponds to one of the main techniques for characterization of structures in crystalline materials widely used in the identification of minerals in samples of geological materials such as rocks. However, the large number of mineral phases present in a rock sample can generate excess peaks in the diffractogram, and it can promote overlapping peaks and induce erroneous identification. The purpose of this study was to perform magnetic separation of minerals from rock samples in order to enable the identification of the minerals by XRD. For this magnetic separation, two samples of rock were selected: a sample of high silica content and a sample with low silica content. The magnetic separation of minerals from each sample was performed using the magnetic separator isodynamic Frantz. Posteriorly, the fractions obtained in magnetic separations were analyzed by XRD. In the sample with high silica content, it was obtained a fraction where was identified the accessory mineral epidote, which had not been identified in the total sample diffractogram. In the sample with low silica content, the magnetic separation into several mineral fractions made possible to obtain diffraction patterns with fewer peaks and peaks with higher relative intensities, which allowed its mineralogical characterization. The results showed that the mineral separation by the magnetic separator Frantz made the identification of accessory minerals by XRD and the characterization of samples which have many mineral phases possible, which proves that magnetic separation by Frantz is a method which can assist analyses by XRD. (author)

  7. Standard test method for determining the effective elastic parameter for X-ray diffraction measurements of residual stress

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1998-01-01

    1.1 This test method covers a procedure for experimentally determining the effective elastic parameter, Eeff, for the evaluation of residual and applied stresses by X-ray diffraction techniques. The effective elastic parameter relates macroscopic stress to the strain measured in a particular crystallographic direction in polycrystalline samples. Eeff should not be confused with E, the modulus of elasticity. Rather, it is nominally equivalent to E/(1 + ν) for the particular crystallographic direction, where ν is Poisson's ratio. The effective elastic parameter is influenced by elastic anisotropy and preferred orientation of the sample material. 1.2 This test method is applicable to all X-ray diffraction instruments intended for measurements of macroscopic residual stress that use measurements of the positions of the diffraction peaks in the high back-reflection region to determine changes in lattice spacing. 1.3 This test method is applicable to all X-ray diffraction techniques for residual stress measurem...

  8. The Remote Food Photography Method Accurately Estimates Dry Powdered Foods-The Source of Calories for Many Infants.

    Science.gov (United States)

    Duhé, Abby F; Gilmore, L Anne; Burton, Jeffrey H; Martin, Corby K; Redman, Leanne M

    2016-07-01

    Infant formula is a major source of nutrition for infants, with more than half of all infants in the United States consuming infant formula exclusively or in combination with breast milk. The energy in infant powdered formula is derived from the powder and not the water, making it necessary to develop methods that can accurately estimate the amount of powder used before reconstitution. Our aim was to assess the use of the Remote Food Photography Method to accurately estimate the weight of infant powdered formula before reconstitution among the standard serving sizes. For each serving size (1 scoop, 2 scoops, 3 scoops, and 4 scoops), a set of seven test bottles and photographs were prepared as follow: recommended gram weight of powdered formula of the respective serving size by the manufacturer; three bottles and photographs containing 15%, 10%, and 5% less powdered formula than recommended; and three bottles and photographs containing 5%, 10%, and 15% more powdered formula than recommended (n=28). Ratio estimates of the test photographs as compared to standard photographs were obtained using standard Remote Food Photography Method analysis procedures. The ratio estimates and the US Department of Agriculture data tables were used to generate food and nutrient information to provide the Remote Food Photography Method estimates. Equivalence testing using the two one-sided t tests approach was used to determine equivalence between the actual gram weights and the Remote Food Photography Method estimated weights for all samples, within each serving size, and within underprepared and overprepared bottles. For all bottles, the gram weights estimated by the Remote Food Photography Method were within 5% equivalence bounds with a slight underestimation of 0.05 g (90% CI -0.49 to 0.40; P<0.001) and mean percent error ranging between 0.32% and 1.58% among the four serving sizes. The maximum observed mean error was an overestimation of 1.58% of powdered formula by the Remote

  9. Characterization of working iron Fischer-Tropsch catalysts using quantitative diffraction methods

    Science.gov (United States)

    Mansker, Linda Denise

    This study presents the results of the ex-situ characterization of working iron Fischer-Tropsch synthesis (F-TS) catalysts, reacted hundreds of hours at elevated pressures, using a new quantitative x-ray diffraction analytical methodology. Compositions, iron phase structures, and phase particle morphologies were determined and correlated with the observed reaction kinetics. Conclusions were drawn about the character of each catalyst in its most and least active state. The identity of the active phase(s) in the Fe F-TS catalyst has been vigorously debated for more than 45 years. The highly-reduced catalyst, used to convert coal-derived syngas to hydrocarbon products, is thought to form a mixture of oxides, metal, and carbides upon pretreatment and reaction. Commonly, Soxhlet extraction is used to effect catalyst-product slurry separation; however, the extraction process could be producing irreversible changes in the catalyst, contributing to the conflicting results in the literature. X-ray diffraction doesn't require analyte-matrix separation before analysis, and can detect trace phases down to 300 ppm/2 nm; thus, working catalyst slurries could be characterized as-sampled. Data were quantitatively interpreted employing first principles methods, including the Rietveld polycrystalline structure method. Pretreated catalysts and pure phases were examined experimentally and modeled to explore specific behavior under x-rays. Then, the working catalyst slurries were quantitatively characterized. Empirical quantitation factors were calculated from experimental data or single crystal parameters, then validated using the Rietveld method results. In the most active form, after pretreatment in H 2 or in CO at Pambient, well-preserved working catalysts contained significant amounts of Fe7C3 with trace alpha-Fe, once reaction had commenced at elevated pressure. Amounts of Fe3O 4 were constant and small, with carbide dpavg 65 wt%, regardless of pretreatment gas and pressure, with

  10. Preparation and pattern recognition of metallic Ni ultrafine powders by electroless plating

    International Nuclear Information System (INIS)

    Zhang, H.J.; Zhang, H.T.; Wu, X.W.; Wang, Z.L.; Jia, Q.L.; Jia, X.L.

    2006-01-01

    Using hydrazine hydrate as reductant, metallic Ni ultrafine powders were prepared from NiSO 4 aqueous solution by electroless plating method. The factors including concentration of NiSO 4 , bathing temperature, ratio of hydrazine hydrate to NiSO 4 , the pH of the solution, etc., on influence of the yield and average particle size of metallic Ni ultrafine powders were studied in detail. X-ray powders diffraction patterns show that the nickel powders are cubic crystallite. The average crystalline size of the ultrafine nickel powders is about 30 nm. The dielectric and magnetic loss of ultrafine Ni powders-paraffin wax composites were measured by the rectangle waveguide method in the range 8.2-12.4 GHz. The factors for Ni ultrafine powders preparation are optimized by computer pattern recognition program based on principal component analysis, the optimum factors regions with higher yield of metallic Ni ultrafine powders are indicated by this way

  11. Neutron diffraction of γ-aluminium oxynitride

    NARCIS (Netherlands)

    Willems, H.X.; With, de G.; Metselaar, R.; Helmholdt, R.B.; Petersen, K.K.

    1993-01-01

    Neutron diffraction expts. were performed on Al oxynitride (Alon) powders with compns. corresponding to 67.5, 73 and 77.5 mol.% Al2O3. The 73 mol.% powder was produced by reacting Al2O3 and AlN powders for 3 h at 1750 Deg. After reaction the resultant powder was ground with a mortar and pestle to

  12. Superior sinterability of nano-crystalline gadolinium doped ceria powders synthesized by co-precipitation method

    International Nuclear Information System (INIS)

    Hari Prasad, D.; Kim, H.-R.; Park, J.-S.; Son, J.-W.; Kim, B.-K.; Lee, H.-W.; Lee, J.-H.

    2010-01-01

    Reduced sintering temperature of doped ceria can greatly simplify the fabrication process of solid oxide fuel cells (SOFCs) by utilizing the co-firing of all cell components with a single step. In the present study, nano-crystalline gadolinium doped ceria (GDC) powders of high sinterability at lower sintering temperature has been synthesized by co-precipitation at room temperature. The successful synthesis of nano-crystalline GDC was confirmed by XRD, TEM and Raman spectroscopy analysis. Dilatometry studies showed that GDC prepared by this method can be fully densified (97% relative density) at a sintering temperature of 950 o C which is fairly lower than ever before. It has also been found that the sintered samples have a higher ionic conductivity of 1.64 x 10 -2 S cm -1 at 600 o C which is suitable for the intermediate temperature SOFC application.

  13. Preparation and Sintering Behaviour of Alumina Powder by Ammonia Precipitation Method

    Directory of Open Access Journals (Sweden)

    Wang Liuyan

    2017-01-01

    Full Text Available In this paper, alumina precursor was prepared by the ammonia precipitation method which used Al (NO3 3 9H2O as aluminum source and NH4OH as a precipitator, adding a small amount of PEG4000 as the surface active agent. Finally γ-Al2O3 was obtained at 900° for 2h. The stable alumina crystal form of α-Al2O3 was got at 1100° for 2h. The influence of precipitation agent on the precursor was studied by means of TG / DTA and Tem, XRD etc. The effects of the synthesis temperature and time on the phase composition and morphology of the alumina powder were also analysed.

  14. Application of Microscopy and X-ray Diffraction in Optimization of the Production of NiTi Alloy by Powder Metallurgy

    Czech Academy of Sciences Publication Activity Database

    Novák, P.; Školáková, A.; Vojtěch, V.; Knaislová, A.; Pokorný, P.; Moravec, H.; Kopeček, Jaromír; Karlík, M.; Kubatík, Tomáš František

    2014-01-01

    Roč. 14, č. 3 (2014), s. 387-392 ISSN 1213-2489. [Mezinárodní konference „Mikroskopie a nedestruktivní zkoušení materiálů/3./. Litoměřice, 22.10.2014-24.10.2014] R&D Projects: GA ČR(CZ) GA14-03044S Institutional support: RVO:61389021 ; RVO:68378271 Keywords : powder metallurgy * NiTi, * mechanical alloying * reactive sintering Subject RIV: JG - Metallurgy; JG - Metallurgy (FZU-D) http://journal.strojirenskatechnologie.cz/templates/obalky_casopis/XIV_2014-3.pdf

  15. Powder Injection Molding - An innovative manufacturing method for He-cooled DEMO divertor components

    International Nuclear Information System (INIS)

    Antusch, Steffen; Norajitra, Prachai; Piotter, Volker; Ritzhaupt-Kleissl, Hans-Joachim; Spatafora, Luigi

    2011-01-01

    At Karlsruhe Institute of Technology (KIT), a He-cooled divertor design for future fusion power plants has been developed. This concept is based on the use of modular cooling fingers made from tungsten and tungsten alloy, which are presently considered the most promising divertor materials to withstand the specific heat load of 10 MW/m 2 . Since a large number of the finger modules (n > 250,000) are needed for the whole reactor, developing a mass-oriented manufacturing method is indispensable. In this regard, an innovative manufacturing technology, Powder Injection Molding (PIM), has been adapted to W processing at KIT since a couple of years. This production method is deemed promising in view of large-scale production of tungsten parts with high near-net-shape precision, hence, offering an advantage of cost-saving process compared to conventional machining. The complete technological PIM process for tungsten materials and its application on manufacturing of real divertor components, including the design of a new PIM tool is outlined and, results of the examination of the finished product after heat-treatment are discussed. A binary tungsten powder feedstock with a solid load of 50 vol.% was developed and successfully tested in molding experiments. After design, simulation and manufacturing of a new PIM tool, real divertor parts are produced. After heat-treatment (pre-sintering and HIP) the successful finished samples showed a sintered density of approximately 99%, a hardness of 457 HV0.1, a grain size of approximately 5 μm and a microstructure without cracks and porosity.

  16. Freeze drying vs microwave drying–methods for synthesis of sinteractive thoria powders

    Energy Technology Data Exchange (ETDEWEB)

    Annie, D.; Chandramouli, V. [Materials Chemistry Division, Chemistry Group, Indira Gandhi Centre for Atomic Research, Kalpakkam, 602103 (India); Anthonysamy, S., E-mail: sas@igcar.gov.in [Materials Chemistry Division, Chemistry Group, Indira Gandhi Centre for Atomic Research, Kalpakkam, 602103 (India); Ghosh, Chanchal; Divakar, R. [Materials Synthesis and Structural Characterization Division, Materials and Metallurgy Group, Indira Gandhi Centre for Atomic Research, Kalpakkam, 602103 (India)

    2017-02-15

    Thoria powders were synthesized by oxalate precipitation from an aqueous solution of the nitrate. The filtered precipitates were freeze dried or microwave dried before being calcined at 1073 K. The thoria powders obtained were characterized for crystallite size, specific surface area, bulk density, particle size distribution and residual carbon. Microstructure of the product was studied using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Sinterability of the synthesized powders was studied by measuring the density of the sintered compacts. Powders that can be consolidated and sintered to densities ∼96% theoretical density (TD) at 1773 K were obtained.

  17. Hydrothermal treatment of coprecipitated YSZ powders

    International Nuclear Information System (INIS)

    Arakaki, Alexander Rodrigo; Yoshito, Walter Kenji; Ussui, Valter; Lazar, Dolores Ribeiro Ricci

    2009-01-01

    Zirconia stabilized with 8.5 mol% yttria (YSZ) were synthesized by coprecipitation and resulting gels were hydrothermally treated at 200°C and 220 PSI for 4, 8 and 16 hours. Products were oven dried at 70°C for 24 hours, uniaxially pressed as pellets and sintered at 1500 °C for 1 hour. Powders were characterized for surface area with N 2 gas adsorption, X-ray diffraction, laser diffraction granulometric analysis and scanning and transmission electronic microscopy. Density of ceramics was measured by an immersion method based on the Archimedes principle. Results showed that powders dried at 70°C are amorphous and after treatment has tetragonal/cubic symmetry. Surface area of powders presented a significant reduction after hydrothermal treatment. Ceramics prepared from hydrothermally treated powders have higher green density but sintered pellets are less dense when compared to that made with powders calcined at 800°C for 1 hour due to the agglomerate state of powders. Solvothermal treatment is a promising procedure to enhance density. (author)

  18. Preparation of cauliflower-like shaped Ba{sub 0.6}Sr{sub 0.4}TiO{sub 3} powders by modified oxalate co-precipitation method

    Energy Technology Data Exchange (ETDEWEB)

    Li Mingli [School of Materials Science and Engineering, Key Laboratory for Advanced Ceramics and Machining Technology of Ministry of Education, Tianjin University, Tianjin 300072 (China)], E-mail: lml@tju.edu.cn; Xu Mingxia [School of Materials Science and Engineering, Key Laboratory for Advanced Ceramics and Machining Technology of Ministry of Education, Tianjin University, Tianjin 300072 (China)

    2009-04-17

    The quantitative barium-strontium titanyl oxalate (Ba{sub 0.6}Sr{sub 0.4}TiO(C{sub 2}O{sub 4}){sub 2}.4H{sub 2}O, BSTO) precursor powders were prepared by the modified oxalate co-preparation method. It was based on the cation-exchange reaction between the stoichiometric solutions of oxalotitanic acid (H{sub 2}TiO(C{sub 2}O{sub 4}){sub 2}, HTO) and barium + strontium nitrate solution containing stoichiometric quantities of Ba and Sr ions. The pyrolysis of BSTO at 800 deg. C/4 h in air produced the homogeneous cauliflower-like shaped barium-strontium titanate (Ba{sub 0.6}Sr{sub 0.4}TiO{sub 3}, BST) powders. The effect of polyethylene glycol (PEG) on morphology of BSTO and BST powders was also investigated. The characterization studies were carried on the as-dried BSTO and calcined BST powders by various physicochemical techniques, IR, X-ray diffraction (XRD), scanning electron microscopy (SEM), etc. The BSTO and BST powders obtained by aforementioned technique without PEG were homogeneous with spherical shape. The particles grew into spindle shape with the effect of PEG.

  19. High temperature neutron powder diffraction study of the Cu{sub 12}Sb{sub 4}S{sub 13} and Cu{sub 4}Sn{sub 7}S{sub 16} phases

    Energy Technology Data Exchange (ETDEWEB)

    Lemoine, Pierric, E-mail: pierric.lemoine@univ-rennes1.fr [Institut des Sciences Chimiques de Rennes, UMR-CNRS 6226, 263 Avenue du Général Leclerc, CS 74205, 35042 Rennes Cedex (France); Bourgès, Cédric; Barbier, Tristan [Laboratoire CRISMAT, UMR-CNRS 6508, ENSICAEN, 6 Boulevard du Maréchal Juin, 14050 Caen Cedex 04 (France); Nassif, Vivian [CNRS Institut NEEL, F-38000 Grenoble (France); Université de Grenoble Alpes, Institut NEEL, F-38000 Grenoble (France); Cordier, Stéphane [Institut des Sciences Chimiques de Rennes, UMR-CNRS 6226, 263 Avenue du Général Leclerc, CS 74205, 35042 Rennes Cedex (France); Guilmeau, Emmanuel [Laboratoire CRISMAT, UMR-CNRS 6508, ENSICAEN, 6 Boulevard du Maréchal Juin, 14050 Caen Cedex 04 (France)

    2017-03-15

    Ternary copper-containing sulfides Cu{sub 12}Sb{sub 4}S{sub 13} and Cu{sub 4}Sn{sub 7}S{sub 16} have attracted considerable interest since few years due to their high-efficiency conversion as absorbers for solar energy and promising thermoelectric materials. We report therein on the decomposition study of Cu{sub 12}Sb{sub 4}S{sub 13} and Cu{sub 4}Sn{sub 7}S{sub 16} phases using high temperature in situ neutron powder diffraction. Our results obtained at a heating rate of 2.5 K/min indicate that: (i) Cu{sub 12}Sb{sub 4}S{sub 13} decomposes above ≈792 K into Cu{sub 3}SbS{sub 3}, and (ii) Cu{sub 4}Sn{sub 7}S{sub 16} decomposes above ≈891 K into Sn{sub 2}S{sub 3} and a copper-rich sulfide phase of sphalerite ZnS-type structure with an assumed Cu{sub 3}SnS{sub 4} stoichiometry. Both phase decompositions are associated to a sulfur volatilization. While the results on Cu{sub 12}Sb{sub 4}S{sub 13} are in fair agreement with recent published data, the decomposition behavior of Cu{sub 4}Sn{sub 7}S{sub 16} differs from other studies in terms of decomposition temperature, thermal stability and products of reaction. Finally, the crystal structure refinements from neutron powder diffraction data are reported and discussed for the Cu{sub 4}Sn{sub 7}S{sub 16} and tetrahedrite Cu{sub 12}Sb{sub 4}S{sub 13} phases at 300 K, and for the high temperature form of skinnerite Cu{sub 3}SbS{sub 3} at 843 K. - Graphical abstract: In situ neutron powder diffraction data (heating rate of 2.5 K/min) indicates that (i) the ternary Cu{sub 12}Sb{sub 4}S{sub 13} phase is stable up to 792 K and decomposes at higher temperature into Cu{sub 3}SbS{sub 3} and Cu{sub 1.5}Sb{sub 0.5}S{sub 2}, and (ii) the Cu{sub 4}Sn{sub 7}S{sub 16} phase is stable up to 891 K and decomposes at higher temperature into Sn{sub 2}S{sub 3} and a cubic phase of sphalerite ZnS-type structure. Sulfur volatilization likely occurs in order to balance the overall stoichiometry.

  20. Neutron powder diffraction analysis of (Tm{sub 0.50}Ca{sub 0.50})MnO{sub 3} and (Lu{sub 0.50}Ca{sub 0.50})MnO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Martinelli, A., E-mail: alberto.martinelli@spin.cnr.it [SPIN-CNR, C.so Perrone 24, 16152 Genova (Italy); Ferretti, M. [SPIN-CNR, C.so Perrone 24, 16152 Genova (Italy); Universita degli Studi di Genova, Dipartimento di Chimica e Chimica Industriale, Via Dodecaneso 31, 16146 Genova (Italy); Cimberle, M.R. [IMEM-CNR, Via Dodecaneso 33, 16146, Genova (Italy); Ritter, C. [Institute Laue-Langevin, 6 rue Jules Horowitz, 38042 Grenoble Cedex 9 (France)

    2012-12-15

    The crystal and magnetic structures of (Tm{sub 0.50}Ca{sub 0.50})MnO{sub 3} and (Lu{sub 0.50}Ca{sub 0.50})MnO{sub 3} have been investigated between 5 K and 300 K by means of high resolution neutron powder diffraction followed by Rietveld refinement and dc magnetic measurements. During cooling orbital ordering at the Mn sub-lattice takes place at T{sub OO}{approx}280 K in both compounds, inducing an orthorhombic to monoclinic phase transition. As the temperature is further decreased an antiferromagnetic CE-type structure occurs in both compounds at T{sub N}{approx}105 K. The comparison with other (Ln{sub 0.50}Ca{sub 0.50})MnO{sub 3} compounds reveals that at room temperature the average Jahn-Teller distortion increases sharply with the decrease of the ionic radius for lanthanides heavier than Sm. The ordered magnetic moment progressively decreases as the lanthanide ionic radius decreases on account of the decreased values of the Mn-O-Mn bond angles. - Graphical abstract: Rietveld refinement plot for (Tm{sub 0.50}Ca{sub 0.50})MnO{sub 3} obtained from neutron powder diffraction data collected at 5 K; the inset shows the CE-type spin ordering taking place at the Mn sub-lattice. Highlights: Black-Right-Pointing-Pointer The crystal and magnetic structures of (Tm{sub 0.50}Ca{sub 0.50})MnO{sub 3} and (Lu{sub 0.50}Ca{sub 0.50})MnO{sub 3} were analyzed by neutron powder diffraction. Black-Right-Pointing-Pointer Orbital ordering takes place below T{sub OO}{approx}280 K in both compounds. Black-Right-Pointing-Pointer An antiferromagnetic CE-type structure occurs in both compounds below T{sub N}{approx}105 K. Black-Right-Pointing-Pointer A Comparison with other (Ln{sub 0.50}Ca{sub 0.50})MnO{sub 3} compounds is reported.

  1. Structure determination of β- and γ-BaAlF 5 by X-ray and neutron powder diffraction: A model for the α → β γ transitions

    Science.gov (United States)

    Le Bail, Armel; Ferey, Gérard; Mercier, Anne-Marie; De Kozak, Ariel; Samouél, Maurice

    1990-12-01

    β-BaAlF 5 is monoclinic (space group {P2 1}/{n}): a = 5.1517(1), Å, b = 19.5666(4), Å, c = 7.5567(2), Å, β = 92.426(1)°, Z = 8. γ-BaAlF 5 is monoclinic (space group P2 1): a = 5.2584(1), Å, b = 9.7298(2), Å, c = 7.3701(2), Å, β = 90.875(1)°, Z = 4. Both structures are determined ab initio from X-ray powder data; final results are given from neutron powder data refinements ( RI = 0.038, RP = 0.072, and RWP = 0.087 and RI = 0.048, RP = 0.083, and RWP = 0.101 for the β and γ phases, respectively). Like α-BaAlF 5, the β and γ phases are built up from isolated infinite (AlF 5) 2 n- n chains with AlF 6 octahedra sharing corners in a cis-position. Close structural relationships are shown to exist between the BaAl cationic subnetwork of: α-BaAlF 5 and the CrB-type structure; β-BaAlF 5 and the SrAg-type; γ-BaAlF 5 and the FeB-type. The polymorphic transitions are proposed to be topotactic and a displacive mechanism is suggested.

  2. Characterization of powdered fish heads for bone graft biomaterial applications.

    Science.gov (United States)

    Oteyaka, Mustafa Ozgür; Unal, Hasan Hüseyin; Bilici, Namık; Taşçı, Eda

    2013-01-01

    The aim of this study was to define the chemical composition, morphology and crystallography of powdered fish heads of the species Argyrosomus regius for bone graft biomaterial applications. Two sizes of powder were prepared by different grinding methods; Powder A (coarse, d50=68.5 µm) and Powder B (fine, d50=19.1 µm). Samples were analyzed using X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM), thermogravimetry (TG), and energy dispersive X-ray spectroscopy (EDS). The powder was mainly composed of aragonite (CaCO3) and calcite (CaCO3). The XRD pattern of Powder A and B matched standard aragonite and calcite patterns. In addition, the calcium oxide (CaO) phase was found after the calcination of Powder A. Thermogravimetry analysis confirmed total mass losses of 43.6% and 47.3% in Powders A and B, respectively. The microstructure of Powder A was mainly composed of different sizes and tubular shape, whereas Powder B showed agglomerated particles. The high quantity of CaO and other oxides resemble the chemical composition of bone. In general, the powder can be considered as bone graft after transformation to hydroxyapatite phase.

  3. Spheroidization of molybdenum powder by radio frequency thermal plasma

    Science.gov (United States)

    Liu, Xiao-ping; Wang, Kuai-she; Hu, Ping; Chen, Qiang; Volinsky, Alex A.

    2015-11-01

    To control the morphology and particle size of dense spherical molybdenum powder prepared by radio frequency (RF) plasma from irregular molybdenum powder as a precursor, plasma process parameters were optimized in this paper. The effects of the carrier gas flow rate and molybdenum powder feeding rate on the shape and size of the final products were studied. The molybdenum powder morphology was examined using high-resolution scanning electron microscopy. The powder phases were analyzed by X-ray diffraction. The tap density and apparent density of the molybdenum powder were investigated using a Hall flow meter and a Scott volumeter. The optimal process parameters for the spherical molybdenum powder preparation are 50 g/min powder feeding rate and 0.6 m3/h carrier gas rate. In addition, pure spherical molybdenum powder can be obtained from irregular powder, and the tap density is enhanced after plasma processing. The average size is reduced from 72 to 62 µm, and the tap density is increased from 2.7 to 6.2 g/cm3. Therefore, RF plasma is a promising method for the preparation of high-density and high-purity spherical powders.

  4. Untargeted LC-Q-TOF mass spectrometry method for the detection of adulterations in skimmed-milk powder

    NARCIS (Netherlands)

    Cordewener, J.H.G.; Luykx, D.M.A.M.; Frankhuizen, R.; Bremer, M.G.E.G.; Hooijerink, H.; America, A.H.P.

    2009-01-01

    A nontargeted protein identification method was developed to screen for adulterations in skimmed-milk powder (SMP). There are indications of falsified SMP content due to the addition of plant proteins. To demonstrate the reliability and accuracy of the developed comparative LC-MS method using a

  5. Artemether-Lumefantrine Concentrations in Tablets and Powders from Ghana Measured by a New High-Performance Liquid Chromatography Method

    DEFF Research Database (Denmark)

    Debrah, Philip; Nettey, Henry; Miltersen, Katja Kjeldgaard

    2016-01-01

    We developed and validated a new analytical method for the simultaneous quantification of artemether and lumefantrine in fixed-dose tablets and powders for reconstitution into pediatric suspensions (PSs). The method showed linearity (r2 > 0.9947), precision (coefficient of variation < 2%), accura...

  6. A detailed study of the amorphisation reaction in NiMo alloys by diffraction and scattering methods

    International Nuclear Information System (INIS)

    Rose, P.

    1995-01-01

    X-ray and neutron diffraction and neutron small angle scattering (SAS) measurements have been made on NiMo specimens prepared by mechanical alloying (MA). We have extended our earlier studies and measured a new series of MA treated NiMo samples. Molybdenum scatters X-rays more strongly than nickel, but with neutrons, the reverse is the case. Analysis of the X-ray and neutron diffraction patterns together, therefore provides an accurate measurement of the consumption of both constituents in the reaction. The diffraction data on the new samples confirm that the consumption of the parent crystalline materials follows an exponential dependence with the time of MA treatment and also provides evidence of a ''delayed start'' to the reaction. This is consistent with an initial period of mixing of the constituents before the onset of (atomic) interdiffusion and amorphisation. The neutron SAS experiments have been made on Ni 47.7 Mo 52.3 MA treated specimens, which can be ''contrast-matched'' to reduce the scattering from the external surfaces of the powder grains. The new neutron SAS data confirm the presence of fractal surfaces between the alloy constituents, for samples in the early stages of the MA process. (orig.)

  7. Crystal structure and ionic conduction path of solid electrolytic materials by high temperature neutron diffraction method

    International Nuclear Information System (INIS)

    Yashima, Masatomo; Nomura, Katsuhiro

    2005-01-01

    Research of the distribution of oxide ions and the ionic conduction path of bismuth oxide (Bi 2 O 3 ), cerium oxide (CeO 2 ) and lanthanum gallate ((La 0.8 Sr 0.2 )(Ga 0.8 Mg 0.15 Co 0.05 )O 3-δ ) is stated. The high temperature neutron diffraction method, analytical method such as Rietveld method, crystal structure analysis of ionic conductor and MEM (Maximum- Entropy Method) are explained. The nuclear density distribution of oxide ions in bismuth oxide showed so larger distribution in the direction of and than Bi ions that the oxide ions conducted these direction in the crystal. The nuclear density distribution of oxide ions of cerium oxide indicated larger distribution in the direction of than Ce ions and its tendency was remarkable at high temperature. Accordingly, the oxide ions conducted in the direction of and . The oxide ions distribution in lanthanum gallate compound was larger and complicated than positive ions. The oxide ions conducted to by describing an arc between the two stable positions. The nuclear density on the conduction path increased with increasing temperature. This above result corresponded to increase of oxide ion conductivity in the area. (S.Y.)

  8. Development of Extended Ray-tracing method including diffraction, polarization and wave decay effects

    Science.gov (United States)

    Yanagihara, Kota; Kubo, Shin; Dodin, Ilya; Nakamura, Hiroaki; Tsujimura, Toru

    2017-10-01

    Geometrical Optics Ray-tracing is a reasonable numerical analytic approach for describing the Electron Cyclotron resonance Wave (ECW) in slowly varying spatially inhomogeneous plasma. It is well known that the result with this conventional method is adequate in most cases. However, in the case of Helical fusion plasma which has complicated magnetic structure, strong magnetic shear with a large scale length of density can cause a mode coupling of waves outside the last closed flux surface, and complicated absorption structure requires a strong focused wave for ECH. Since conventional Ray Equations to describe ECW do not have any terms to describe the diffraction, polarization and wave decay effects, we can not describe accurately a mode coupling of waves, strong focus waves, behavior of waves in inhomogeneous absorption region and so on. For fundamental solution of these problems, we consider the extension of the Ray-tracing method. Specific process is planned as follows. First, calculate the reference ray by conventional method, and define the local ray-base coordinate system along the reference ray. Then, calculate the evolution of the distributions of amplitude and phase on ray-base coordinate step by step. The progress of our extended method will be presented.

  9. Quantitative determination of phases by X-ray diffraction

    International Nuclear Information System (INIS)

    Azevedo, A.L.T.

    1979-01-01

    The internal standard method for the quantitative determination of phases by X-ray diffraction is presented. The method is applicable to multi-phase materials which may be treated as powder. A discussion on sample preparation and some examples follow. (Author) [pt

  10. Mossbauer, Raman and X-ray diffraction studies of superparamagnetic NiFe2O4 nanoparticles prepared by sol-gel auto-combustion method

    International Nuclear Information System (INIS)

    Ahlawat, Anju; Sathe, V.G.; Reddy, V.R.; Gupta, Ajay

    2011-01-01

    Superparamagnetic nickel ferrite single phase nanoparticles with the average crystallite size of ∼9 nm have been synthesized at a low temperature (220 o C) by the sol-gel auto-combustion method. In the present study the as prepared powder was further calcined at different temperatures for 4 h, resulting in nanoparticles of larger size. The nanoparticles exhibited superparamagnetic behavior and changes in cation distribution as revealed by the Mossbauer, Raman and X-ray diffraction studies. The Mossbauer spectra collected at 5 K and under 5 T applied magnetic field showed mixed spinel structure and canted spin order for the nanoparticles, whereas there is collinear spin order with inverse spinel structure for larger particles. The vibrational spectra of the nanoparticles showed a redshift and broadening in the Raman line shape due to confinement effects. - Highlights: → Mossbauer spectra show a canting angle of 48 o for the nanoparticle samples measured at 5 K and 5 T applied magnetic field, the highest canting angle obtained so far in NiFe 2 O 4 nanoparticles. Site inversion in nanoparticles, thus converting it from inverse spinel to mixed spinel structure. → X-ray diffraction results showed a change in sign for the strain of the nanoparticle sample that showed mixed spinel structure. → Our Raman measurements showed a redshift and broadening for nanoparticle samples that is generally interpreted as a signature of quantum confinement.

  11. Uranium metal and uranium dioxide powder and pellets - Determination of nitrogen content - Method using ammonia-sensing electrode. 1. ed.

    International Nuclear Information System (INIS)

    1994-01-01

    This International Standard specifies an analytical method for determining the nitrogen content in uranium metal and uranium dioxide powder and pellets. It is applicable to the determination of nitrogen, present as nitride, in uranium metal and uranium dioxide powder and pellets. The concentration range within which the method can be used is between 9 μg and 600 μg of nitrogen per gram. Interference can occur from metals which form complex ammines, but these are not normally present in significant amounts

  12. Synthesis and Characterization of Rutile TiO_2 Powder by the Sulfuric Acid Method

    International Nuclear Information System (INIS)

    Choi, Soon Ok; Cho, Jee Hee; Lim, Sung Hwan; Kim, Won Yong

    2012-01-01

    We investigated the experimental method that uses the homogeneous precipitation method to prepare mica flakes-coated rutile-type titania pearlescent pigment with urea as a precipitant. TiO_2 particles exhibit a high reflection of lights and optical properties with chemical stabilities, so they are appropriate for coating on luminescent pigments (mica). The coating principle of mica coated titania with various thicknesses was analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and tested by spectrophotometer. Mica with a particle size in the range of 40-60 um was suspended in water, and metal sulphates and urea were added to the mixture, which was heated to boiling. The change in pH was continuously followed. The metal oxide and crystal structure were affected by the conditions of TiOSO_4 concentration and reaction time with a sintering temperature the range of 800-1100°C.

  13. Synthesis and Characterization of Anatase TiO_2 Powder using a Homogeneous Precipitation Method

    International Nuclear Information System (INIS)

    Choi, Soon Ok; Cho, Jee Hee; Lim, Sung Hwan; Chung, Eun Young

    2011-01-01

    This paper studies the experimental method that uses the homogeneous precipitation method to prepare mica flakes coated with anatase-type titania pearlescent pigment with urea as precipitant. The optimum technology parameters, the chemical composition, the microstructure, and the color property of resulting pigments are discussed. The coating principle of mica coated titania with various coating thickness is analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy(TEM) and tested by spectrophotometer analysis. The colored nanocrystalline pigments with different morphology and coating thickness 45-170 nm were prepared by homogeneous precipitation treatment of TiOSO_4(titanum oxysulfate) aqueous solutions. Characterizations on the pigments show that the pearlescent effects of the pigments depend mainly on mica size, thickness of the metal oxide deposit, its chemical composition, and crystal structure.

  14. Raman spectroscopy method for subsurface detection of food powders through plastic layers

    Science.gov (United States)

    Turmeric (Curcuma longa L.) powder, valued for both medicinal properties and culinary use, has been subject to economically driven hazardous chemical adulteration by the similarly colored but toxic metanil yellow. Such adulterated food powders in sealed containers can often go undetected due to lack...

  15. Methods of improving the production structure and quality of clay powders

    Energy Technology Data Exchange (ETDEWEB)

    Ryabchenko, V I; Lityayeva, Z A

    1981-01-01

    Results are generalized of scientific research work in relation to the quality of argillaceous raw material and powders made of it to prepare drilling fluids. The output of the solution of definite effective viscosity is adopted as the criterion for the quality of clay powders. Recommendations are made for the use of jet grinding of clays and the technology of plasticizing.

  16. Oxygen stoichiometry and the structure of Tl[sub 2]Ba[sub 2]Ca[sub 2]Cu[sub 3]O[sub 10-y]. A high-resolution powder neutron diffraction study

    Energy Technology Data Exchange (ETDEWEB)

    Ogborne, D.M.; Weller, M.T.; Lanchester, P.C. (Dept. of Chemistry and Physics, Univ. of Southampton (United Kingdom))

    1992-09-15

    Samples of Tl[sub 2]Ba[sub 2]Ca[sub 2]Cu[sub 3]O[sub 10-y] have been prepared with three different oxygen stoichiometries by reaction under various oxygen gas partial pressures. Powder neutron diffraction studies on these materials show that for y > 0 oxygen vacancies exist in the thallium-oxygen layer; filling this site results in a contraction of the lattice with concomitant reduction in the apical Cu-O bond length but with an expansion of the copper-oxygen interlayer distance. These structural changes which occur as a function of oxygen content are discussed in terms of the superconducting properties of these materials. (orig.).

  17. Neutron powder diffraction investigation on the crystal and magnetic structure of (Ho{sub 0.50+x}Ca{sub 0.50-x})(Mn{sub 1-x}Cr{sub x})O{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Martinelli, A; Ferretti, M [SPIN-CNR, Corso Perrone 24, 16152 Genova (Italy); Castellano, C [Dipartimento di Chimica Strutturale e Stereochimica Inorganica, Universita degli Studi di Milano, Via C Venezian 21, 20133 Milano (Italy); Cimberle, M R; Masini, R [IMEM-CNR, Via Dodecaneso 33, 16146 Genova (Italy); Ritter, C, E-mail: alberto.martinelli@spin.cnr.it [Institute Laue-Langevin, 6 rue Jules Horowitz, 38042 Grenoble Cedex 9 (France)

    2011-10-19

    The crystal and magnetic structure of (Ho{sub 0.50+x}Ca{sub 0.50-x})(Mn{sub 1-x}Cr{sub x})O{sub 3} (x = 0.00, 0.01, 0.02, 0.03) has been investigated between 5 and 300 K by means of neutron powder diffraction followed by Rietveld refinement and dc magnetic measurements. During cooling an orthorhombic to monoclinic phase transition occurs on account of the charge and orbital ordering taking place in the Mn sub-lattice; at low temperature phase separation takes place and the main monoclinic phase coexists with a secondary orthorhombic phase, whose amount slightly increases with the increase of Cr content. Cr{sup 3+} is not involved in orbital ordering or superexchange interactions. The charge and magnetic ordering are decoupled: the Mn moments order according to a CE-type structure in all samples. (paper)

  18. Magnetic ordering in the monoclinic structure of Nd5Si1.45Ge2.55 and Pr5Si1.5Ge2.5 studied by means of neutron powder diffraction

    International Nuclear Information System (INIS)

    Magen, C; Ritter, C; Morellon, L; Algarabel, P A; Ibarra, M R

    2004-01-01

    The compounds Nd 5 Si 1.45 Ge 2.55 and Pr 5 Si 1.5 Ge 2.5 have been investigated by means of magnetization measurements and neutron powder diffraction techniques. These alloys present a room-temperature monoclinic Gd 5 Si 2 Ge 2 -type crystallographic structure and, on cooling, both systems order ferromagnetically, at T C = 56 and 32 K, respectively, from a high-temperature paramagnetic to a low-temperature complex canted ferromagnetic state. The monoclinic crystallographic structure remains unchanged upon cooling down to 4 K, demonstrating the existence of a monoclinic ferromagnetic phase, and the possibility of a full decoupling of magnetic and crystallographic degrees of freedom in the 5:4 lanthanide intermetallic compounds

  19. The Remote Food Photography Method accurately estimates dry powdered foods—the source of calories for many infants

    Science.gov (United States)

    Duhé, Abby F.; Gilmore, L. Anne; Burton, Jeffrey H.; Martin, Corby K.; Redman, Leanne M.

    2016-01-01

    Background Infant formula is a major source of nutrition for infants with over half of all infants in the United States consuming infant formula exclusively or in combination with breast milk. The energy in infant powdered formula is derived from the powder and not the water making it necessary to develop methods that can accurately estimate the amount of powder used prior to reconstitution. Objective To assess the use of the Remote Food Photography Method (RFPM) to accurately estimate the weight of infant powdered formula before reconstitution among the standard serving sizes. Methods For each serving size (1-scoop, 2-scoop, 3-scoop, and 4-scoop), a set of seven test bottles and photographs were prepared including the recommended gram weight of powdered formula of the respective serving size by the manufacturer, three bottles and photographs containing 15%, 10%, and 5% less powdered formula than recommended, and three bottles and photographs containing 5%, 10%, and 15% more powdered formula than recommended (n=28). Ratio estimates of the test photographs as compared to standard photographs were obtained using standard RFPM analysis procedures. The ratio estimates and the United States Department of Agriculture (USDA) data tables were used to generate food and nutrient information to provide the RFPM estimates. Statistical Analyses Performed Equivalence testing using the two one-sided t- test (TOST) approach was used to determine equivalence between the actual gram weights and the RFPM estimated weights for all samples, within each serving size, and within under-prepared and over-prepared bottles. Results For all bottles, the gram weights estimated by the RFPM were within 5% equivalence bounds with a slight under-estimation of 0.05 g (90% CI [−0.49, 0.40]; p<0.001) and mean percent error ranging between 0.32% and 1.58% among the four serving sizes. Conclusion The maximum observed mean error was an overestimation of 1.58% of powdered formula by the RFPM under

  20. Pressure-induced phase transitions in organic molecular crystals: a combination of x-ray single-crystal and powder diffraction, raman and IR-spectroscopy

    International Nuclear Information System (INIS)

    Boldyreva, E V; Goryainov, S V; Seryotkin, Y V; Kolesnik, E N; Shakhtshneider, T P; Ivashevskaya, S N; Drebushchak, T N; Sowa, H; Ahsbahs, H; Chernyshev, V V; Dmitriev, V P

    2008-01-01

    The contribution summarizes the results of recent studies of phase transitions induced by high pressure in a number of molecular organic crystals, such as polymorphs of paracetamol, chlorpropamide, polymorphs of glycine, L- and DL-serine, β-alanine. The main attention is paid to the following topics: (1) Reversible / irreversible transformations; (2) Different behavior of single crystals / powders; (3) The role of pressure-transmitting liquid; (4) The role of the kinetic factors: phase transitions on decompression, or after a long storage at a selected pressure; (5) Isosymmetric phase transitions; (6) The role of the changes in the hydrogen bond networks / intramolecular conformational changes in the phase transitions; (7) Superstructures / nanostructures formed as a result of pressure-induced phase transitions