The Determination of Low Levels of Quartz in Commercial Kaolins by X-ray Diffraction

1992 ◽  
Vol 7 (2) ◽  
pp. 71-76 ◽  
Author(s):  
N.J. Elton ◽  
P.D. Salt ◽  
J.M. Adams
Keyword(s):  
United States ◽  
Data Collection ◽  
The United States ◽  
X Ray Diffraction ◽  
X Ray ◽  
Respirable Fraction ◽  
Profile Fitting ◽  
Potential Problems ◽  
Low Levels

AbstractLegislation in the United States and Canada requires labelling of products containing ≥ 0.1 wt.% crystalline silica. Kaolin clays are used in a variety of industries and usually contain low levels of total (i.e., respirable plus non-respirable) quartz, even after beneficiation. X-ray diffraction procedures have been developed here which are suitable for the quantification of total quartz in commercial kaolins with accuracy sufficient to satisfy the legislation. Separation and analysis of the respirable fraction is not addressed in this paper; however, the procedures described would be applicable to such samples if sufficient were available. Use of the 50.1° 2θrather than the 26.6° 26 (CuKα) quartz peak avoids most of the potential problems of overlap with reflections from other accessory minerals. It is shown that profile fitting techniques and optimised experimental procedures allow the determination of quartz in bulk samples to ± 0.03 wt.% (95% confidence) at the 0.1 wt.% level, and ± 0.1 wt.% at the 1.0 wt.% level, with tolerable data collection times.

Determination of low levels of retained austenite in low-carbon high-manganese steel using X-ray diffraction

2015 ◽  
Vol 628 ◽  
pp. 110-115 ◽  
Author(s):  
Helder Carvalho Ferreira ◽  
Francisco Jose Martins Boratto ◽  
Vicente Tadeu Lopes Buono
Keyword(s):  
Retained Austenite ◽  
Manganese Steel ◽  
Low Carbon ◽  
X Ray Diffraction ◽  
High Manganese ◽  
High Manganese Steel ◽  
X Ray ◽  
Low Levels

Determination of low levels of free fibres of chrysotile in contaminated soils by X-ray diffraction and FTIR spectroscopy

2003 ◽  
Vol 376 (5) ◽  
pp. 653-658 ◽  
Author(s):  
E. Foresti ◽  
M. Gazzano ◽  
A. F. Gualtieri ◽  
I. G. Lesci ◽  
B. Lunelli ◽  
...  
Keyword(s):  
Ftir Spectroscopy ◽  
Contaminated Soils ◽  
X Ray Diffraction ◽  
X Ray ◽  
Low Levels

Determination of minor quantities of linezolid polymorphs in a drug substance and tablet formulation by powder X-ray diffraction technique

2017 ◽  
Vol 32 (2) ◽  
pp. 78-85 ◽  
Author(s):  
Mengying Sun ◽  
Xiurong Hu ◽  
Xinbo Zhou ◽  
Jianming Gu
Keyword(s):  
Limit Of Detection ◽  
Drug Product ◽  
Multidrug Resistant ◽  
Tablet Formulation ◽  
Drug Substance ◽  
X Ray Diffraction ◽  
X Ray ◽  
Profile Fitting ◽  
Full Profile

Linezolid (LZD) is one of the first commercially available synthetic oxazolidinone antibiotics and is widely used for the treatment of multidrug-resistant Gram-positive bacterial infection. LZD was found to have five polymorphic forms. The most stable and commercialized polymorphs are known as forms II and IV. Trace content of form II in LZD form IV will cause to transition LZD form IV to II rapidly. Powder X-ray diffraction (PXRD) methods were evaluated for the determination of the polymorphic content of the drug substance and drug product. The estimated limit of detection values of the single peak method for LZD polymorph form II in drug substance and tablet formulation were 0.4 and 0.6%, respectively, while the limit of detection value of Rietveld Refinement (full-profile fitting) evaluated LZD polymorph form II in drug substance was 0.2%. The results clearly show that levels <1 wt.% (in active pharmaceutical ingredients) and 2 wt.% (in tablets) LZD form II in form IV can be detected and quantified by PXRD. Validation of the analytical method proved that the method is repeatable, sensitive, and accurate.

Quantitative Structural and Chemical Analysis of Thin Films Part I

MRS Bulletin ◽  
1992 ◽  
Vol 17 (12) ◽  
pp. 20-23
Author(s):  
Y. Bruynseraede ◽  
Ivan K. Schuller
Keyword(s):  
Thin Films ◽  
The United States ◽  
Quantitative Information ◽  
Interfacial Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structure Changes ◽  
Recent Developments ◽  
Basic And Applied Research

Thin-film materials are playing an ever-increasing role in basic and applied research and are the basis for a large number of devices. In many cases, thin films are used in multilayered configurations so that the interfaces between different materials play a key role in their properties. The thicknesses of thin films being investigated approach interatomic spacing, so interfacial structure and chemistry become dominant. The field is now at a stage where it is no longer sufficient to only obtain qualitative information; it is also necessary to understand the structure and chemistry quantitatively and to determine limits on the accuracy of the various characterization tools. The present and next issues of the MRS Bulletin bring together a number of experts in the most commonly used characterization tools. To highlight and encourage international collaboration, the articles presented here are jointly written by scientific groups in the United States and Europe.The first issue of this series is dedicated to the most commonly used techniques: electron microscopy, x-ray diffraction, and surface analysis. The article on electron diffraction by Ourmazd, Scheffler, Heinemann, and Rouviere presents studies of atomic resolution microscopy and their limitations. Aspects highlighted are the importance of comparing simulations to the images obtained in the electron microscope, and the importance of theoretical studies to obtain quantitative information. The article by Fullerton, Bruynseraede, and Schuller describes recent developments in the field of x-ray diffraction. This article focuses on a refinement technique capable of quantitative determination of interfacial roughness, interdiffusion, and crystal structure changes in a variety of novel multilayer configurations.

scholarly journals POTENTIAL OF CELLULASE OF PENICILLIUM VERMICULATUM FOR PREPARATION AND CHARACTERIZATION OF MICROCRYSTALLINE CELLULOSE PRODUCED FROM α-CELLULOSE OF KAPOK PERICARPIUM (CEIBA PENTANDRA)

2019 ◽  
pp. 92-97
Author(s):  
HERMAN SURYADI ◽  
SUTRIYO ◽  
Mira Junnisa ◽  
YULIANITA PRATIWI INDAH LESTARI
Keyword(s):  
United States ◽  
Microcrystalline Cellulose ◽  
Cellulase Activity ◽  
The United States ◽  
X Ray Diffraction ◽  
Clear Zone ◽  
United States Pharmacopoeia ◽  
X Ray ◽  
Particle Size Analyzer

Objective: This study aimed to find psychochemical properties of microcrystalline cellulose (MCC) obtained from α-cellulose kapok pericarpium. Methods: The cellulase activity was screened by clear zone and sugar reduction method. The enzym from selected mold was purified by diethylaminoethyl (DEAE) chromatography. α-cellulose of kapok pericarpium was hydrolyzed using the purified cellulase enzymes. Microcrystalline cellulose (MCC) identified by Fourier transform infrared (FTIR) spectrometry, and qualitative analysis test. The samples were characterized for pH test, x-ray diffraction (XRD), and particle size analyzer (PSA). Results: The optimum cellulase activity was shown by Penicillium vermiculatum. It’s clear zone diameter around 3 cm and the cellulase activity was 67.73±0.25 mU/ml. The strongest cellulase activity was detected from 1st fraction (P1) out of 6 column fractions with optimum activity at 1.177±2 mU/ml. The optimal conditions for microcrystalline cellulose (MCC) preparation were at 50 ˚C, for 2 ours, using 20 ml of acetate buffer pH 5 and 2 ml of cellulase enzyme. Microcrystalline cellulose (MCC) obtained at 78% w/w and its FTIR spectrum and x-ray diffractogram similar to reference while the pH of MCC was fulfilled requirements of The United States Pharmacopoeia 2007. Conclusion: The use of purified enzyme of cellulase has succeded in microcrystalline cellulose (MCC) preparation andmicrocrystalline cellulose (MCC) obtained was 78% w/w, with similar characteristics to reference (Avicel PH 101) and the pH of MCC was fulfilled requirements of The United States Pharmacopoeia 2007.

A new kaolinite order index based on XRD profile fitting

Clay Minerals ◽  
2006 ◽  
Vol 41 (4) ◽  
pp. 811-817 ◽  
Author(s):  
P. Aparicio ◽  
E. Galán ◽  
R. E. Ferrell
Keyword(s):  
Silica Gels ◽  
X Ray Diffraction ◽  
X Ray ◽  
Amorphous Phases ◽  
Structural Order ◽  
Profile Fitting ◽  
Overlapping Peaks ◽  
Highly Correlated

AbstractThe determination of kaolinite order-disorder by X-ray diffraction is problematic due to overlapping peaks from associated kaolin minerals and X-ray amorphous phases. This paper presents a new index (Aparicio-Gala´n-Ferrell index — AGFI), measured on 02land 11lreflections after decomposing individual peaks in the complex diffraction band in an effort to reduce interferences. The new index was tested with three kaolins, of varying structural order, and their admixtures containing different percentages of quartz, feldspar, illite, smectite, chlorite, halloysite and Fe hydroxides and silica gels. The AGFI is highly correlated with the percentage of low-defect kaolinite and the Hinckley Index. It is not as prone to interference by associated minerals and X-ray amorphous phases as other indices. The AGFI can be used to determine kaolinite order-disorder in a wide variety of kaolins and kaolinitic rocks; the only prerequisite is that the kaolinite content should be >10 wt.% in order for the results to be reproducible.

The discreditation of girdite

2017 ◽  
Vol 81 (5) ◽  
pp. 1125-1128 ◽  
Author(s):  
Anthony R. Kampf ◽  
Stuart J. Mills ◽  
Mike S. Rumsey
Keyword(s):  
United States ◽  
Natural History ◽  
Smithsonian Institution ◽  
Original Description ◽  
The United States ◽  
National Museum ◽  
X Ray Diffraction ◽  
History Museum ◽  
X Ray ◽  
Cochise County

AbstractGirdite, a mineral described byWilliams in 1979 from the Grand Central mine, Tombstone, Cochise County, Arizona, USA, has been re-examined by powder X-ray diffraction, single-crystal X-ray diffraction and electron microprobe. Type material from The Natural History Museum, London and the United States National Museum of Natural History (Smithsonian Institution) was examined. The original description of girdite is shown to have been based upon data obtained from at least two and possibly three different phases, one corresponding to ottoite and another probably corresponding to oboyerite, although the latter itself appears to be a mixture. The discreditation of girdite as a valid mineral species has been approved by the IMA-CNMNC, Proposal 16-G.

Sem and X-Ray Analysis of Renal and Biliary Calculi

1976 ◽  
Vol 34 ◽  
pp. 306-307
Author(s):  
R. J. Narconis ◽  
G. L. Johnson
Keyword(s):  
Chemical Constituents ◽  
Natural State ◽  
X Ray Diffraction ◽  
Chemical Methods ◽  
X Ray ◽  
Additional Dimension ◽  
Biliary Calculi ◽  
Calculus Formation ◽  
Scanning Electron

Analysis of the constituents of renal and biliary calculi may be of help in the management of patients with calculous disease. Several methods of analysis are available for identifying these constituents. Most common are chemical methods, optical crystallography, x-ray diffraction, and infrared spectroscopy. The application of a SEM with x-ray analysis capabilities should be considered as an additional alternative.A scanning electron microscope equipped with an x-ray “mapping” attachment offers an additional dimension in its ability to locate elemental constituents geographically, and thus, provide a clue in determination of possible metabolic etiology in calculus formation. The ability of this method to give an undisturbed view of adjacent layers of elements in their natural state is of advantage in determining the sequence of formation of subsequent layers of chemical constituents.

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