Use of an air brush to spray dry samples for X-ray powder diffraction

Clay Minerals ◽  
1999 ◽  
Vol 34 (1) ◽  
pp. 127-135 ◽  
Author(s):  
S. Hillier
Keyword(s):  
Bulk Density ◽  
Powder Diffraction ◽  
Marked Improvement ◽  
Smooth Surface ◽  
Preferred Orientation ◽  
Spray Drier ◽  
Spray Dry ◽  
X Ray ◽  
Spray Gun ◽  
Spray Dried

AbstractThe construction and operation of a spray drier is described where the spray is produced using an air brush, essentially a miniature spray gun. The spray-dried products consist of spheres 50–60 µm in diameter and typical product recoveries are 80%, a marked improvement over simple two-nozzle systems. The spray-dried samples are easy to load into XRD powder holders and present a smooth surface and relatively constant bulk density to the X-ray beam. Problems of preferred orientation are effectively eliminated and the resulting X-ray powder patterns are completely reproducible by different operators.

X-ray Powder Diffraction QPA by Rietveid Pattern- Fitting - Scope and Limitations

1989 ◽  
Vol 33 ◽  
pp. 269-275 ◽  
Author(s):  
B.H. O'Cannar ◽  
Li Deyu ◽  
B. Jordan ◽  
M. D. Raven ◽  
P. G. Fazey
Keyword(s):  
Powder Diffraction ◽  
Preferred Orientation ◽  
Analytical Science ◽  
Materials Analysis ◽  
X Ray ◽  
University Of Technology ◽  
Science Group

AbstractThe X-ray Analytical Science Group at Curtin university of Technology has been developing and evaluating Rietveld pattern-fitting for materials analysis since 1985. The results are reviewed with particular reference to preferred orientation, crystallinity and phase abundance.

Comparative evaluation of the March and generalized spherical harmonic preferred orientation models using X-ray diffraction data for molybdite and calcite powders

2005 ◽  
Vol 38 (1) ◽  
pp. 158-167 ◽  
Author(s):  
Husin Sitepu ◽  
Brian H. O'Connor ◽  
Deyu Li
Keyword(s):  
Powder Diffraction ◽  
Diffraction Data ◽  
Spherical Harmonic ◽  
Comparative Evaluation ◽  
Preferred Orientation ◽  
Composition Analysis ◽  
Powder Diffraction Data ◽  
X Ray Diffraction ◽  
Crystalline Materials ◽  
X Ray

Preferred crystallographic orientation,i.e.texture in crystalline materials powder diffraction data, can cause serious systematic errors in phase composition analysis and also in crystal structure determination. The March model [Dollase (1986).J. Appl. Cryst.19, 267–272] has been used widely in Rietveld refinement for correcting powder diffraction intensities with respect to the effects of preferred orientation. In the present study, a comparative evaluation of the March model and the generalized spherical harmonic [Von Dreele (1997).J. Appl. Cryst.30, 517–525] description for preferred orientation was performed with X-ray powder diffraction data for molybdite (MoO3) and calcite (CaCO3) powders uniaxially pressed at five different pressures. Additional molybdite and calcite powders, to which 50% by weight silica gel had been added, were prepared to extend the range of preferred orientations considered. The patterns were analyzed initially assuming random orientation of the crystallites and subsequently the March model was used to correct the preferred orientation. The refinement results were compared with parallel refinements conducted with the generalized spherical harmonic [Sitepu (2002).J. Appl. Cryst.35,274–277]. The results obtained show that the generalized spherical harmonic description generally provided superior figures-of-merit compared with the March model results.

Observations on Factor X Activity after Adsorption to Barium Sulphate

1972 ◽  
Vol 28 (02) ◽  
pp. 306-316
Author(s):  
R. M Howell ◽  
R. J Dupe
Keyword(s):  
Bulk Density ◽  
Esterase Activity ◽  
Smooth Surface ◽  
Barium Sulphate ◽  
Surface Activation ◽  
Factor X ◽  
Clotting Factors ◽  
Microscopic Appearance ◽  
X Ray ◽  
Crystalline Surface

SummaryThe amount of preformed clotting activity exhibited by factor X was found to be closely related to the bulk density of the barium sulphate used for its adsorption from serum.The X-ray grade of barium sulphate compares closely with that manufactured by precipitation and its bulk density is half that of the soil grade which is similar to the material obtained by grinding natural barytes. Microscopically, the soil grade shows an irregular crystalline surface and when used for the adsorption of serum, the resulting eluate has a greater clotting and esterase activity than is the case when the X-ray grade, which has a smooth surface, is used. Possible mechanisms leading to the surface activation of factor X by barium sulphate are discussed and the findings are also related to earlier observations on variations in the availability of serum thrombotic accelerator (STA) after its adsorption to the same grade of barium sulphate.The importance of defining the barium sulphate used for the adsorption of clotting factors in terms of its physical properties and microscopic appearance is emphasised.

X-ray powder diffraction data for acetamidinium formate C3H8N2O2, elimination of preferred orientation effect

2017 ◽  
Vol 32 (4) ◽  
pp. 268-270
Author(s):  
J. Maixner ◽  
P. Kačer
Keyword(s):  
Powder Diffraction ◽  
Diffraction Data ◽  
Unit Cell Volume ◽  
Preferred Orientation ◽  
Unit Cell ◽  
Powder Diffraction Data ◽  
Unit Cell Parameters ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters

X-ray powder diffraction data, unit-cell parameters, and space group for acetamidinium formate, C3H8N2O2, are reported [a = 6.4564(5) Å, c = 13.021 (3) Å, unit-cell volume V = 542.8(3) Å3, M.p. = 215(1)°C, ρc = 1.274 g.cm−3, ρm = 1.269 g.cm−3, Z = 4, and space group P43212]. The front-loaded technique got sample with strong preferred orientation because of plate-like shape of crystallites, so the capillary packing was used for final powder data collection. All measured lines were indexed and are consistent with the P43212 space group. No detectable impurities were observed.

Use of X-Ray Powder Diffraction Rietveld Pattern-Fitting for Characterising Preferred Orientation in Gibbsites

1990 ◽  
Vol 5 (2) ◽  
pp. 79-85 ◽  
Author(s):  
Li Deyu ◽  
Brian H. O'Connor ◽  
Gerald I.D. Roach ◽  
John B. Cornell
Keyword(s):  
Powder Diffraction ◽  
Correction Method ◽  
Preferred Orientation ◽  
Empirical Measure ◽  
General Application ◽  
X Ray ◽  
Line Intensities ◽  
Orientation Effects ◽  
Xrpd Pattern

AbstractA study has been conducted with gibbsite specimens, on the use of Rietveld X-ray powder diffraction (XRPD) pattern fitting for quantitating preferred orientation in powders. This study has shown that an earlier formula gives results which correlate closely with an empirical measure of morphology proposed recently for gibbsite powders, viz., the ratio of the XRPD intensities for the (002) line and the (110, 200) doublet lines. A method is proposed on the basis of this correlation for the correction for preferred orientation of line intensities in gibbsite powder patterns. The correction method appears to have excellent potential for XRPD quantification of gibbsite levels in mixtures, and could have general application for coping with preferred orientation effects in the quantitation of other phases.

Texture Characterisation in X-Ray Powder Diffraction using the March Formula

1991 ◽  
Vol 35 (A) ◽  
pp. 277-283 ◽  
Author(s):  
B.H. O'Connor ◽  
D.Y. Li ◽  
H. Sitepu
Keyword(s):  
Powder Diffraction ◽  
Systematic Errors ◽  
Rietveld Analysis ◽  
Preferred Orientation ◽  
Ratio Method ◽  
Powder Diffraction Data ◽  
Selected Lines ◽  
General Applicability ◽  
Crystalline Materials ◽  
X Ray

AbstractTexture, i.e. preferred orientation (PO), of crystallites can cause serious systematic errors in quantitative analysis of crystalline materials using x-ray powder diffraction (XRPD) data. The singleparameter model of March (1932), proposed by Dollase (1986) for use in powder diffractometry is a promising mathematical formalism for correcting PO in XRPD analysis of uniaxially-oriented specimens. O'Connor et al. (1991) successfully applied the March formula in applying preferred orientation corrections for gibbsites, Al(OH)3, using Rietveld pattern-fitting and a line ratio method in which corrections are determined according to the intensity ratios of selected lines. The paper gives an appraisal of the general applicability of the methods considered by Li and O'Connor with particular reference to powder diffraction data for gibbsite, molybdite (MoO3), calcite (CaCO3) and kaolinite specimens. It is shown that some caution should be exercised when using the March formula to describe PO in Rietveld analysis.

Quantitative Phase Analysis of Devonian Shales by Computer Controlled X-Ray Diffraction of Spray Dried Samples

1978 ◽  
Vol 22 ◽  
pp. 181-191 ◽  
Author(s):  
Steven T. Smith ◽  
Robert L. Snyder ◽  
W. E. Brownell
Keyword(s):  
Quantitative Analysis ◽  
Phase Analysis ◽  
Powder Diffraction ◽  
Convenient Method ◽  
Quantitative Phase Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Intractable Problems ◽  
Computer Controlled ◽  
Spray Dried

Spray drying is shown to be an effective and rapid method for preparing samples for quantitative analysis by x-ray powder diffraction. Previously intractable problems like the simultaneous analysis of multiple phases in orientation prone systems can be carried out. Using this method, and a computer controlled diffractometer, five and six phase analyses of Devonian shales can be accomplished in approximately forty minutes. A rapid and convenient method for using the absorption diffraction technique for x-ray quantitative analysis is described.

Obtaining optimal structural data from X-ray powder diffraction using the Rietveld method

2014 ◽  
Vol 29 (4) ◽  
pp. 396-403 ◽  
Author(s):  
Shanke Liu ◽  
He Li ◽  
Jianming Liu
Keyword(s):  
Crystal Structure ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Rietveld Method ◽  
Low Cost ◽  
Structural Data ◽  
Preferred Orientation ◽  
X Ray

Diffraction data of calcite were collected using a conventional Bragg–Brentano diffractometer, which is a convenient, low-cost, and highly popular in-house instrument, and its crystal structure was refined by the Rietveld method. This paper shows how one treats preferred orientation and how different refinement strategies affect the accuracy of the result.

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