X-Ray Diffraction Analysis of Prehistoric Pottery

1973 ◽  
Vol 38 (3) ◽  
pp. 339-344 ◽  
Author(s):  
John W. Weymouth
Keyword(s):  
Quantitative Analysis ◽  
Relative Abundance ◽  
Preliminary Report ◽  
Quantitative Method ◽  
Chemical Elements ◽  
X Ray Diffraction ◽  
Qualitative Information ◽  
X Ray ◽  
Prehistoric Pottery ◽  
Diffraction Patterns

AbstractThis is a preliminary report on a quantitative method for grouping prehistoric pottery using x-ray diffraction techniques. Of the various analytical methods that have been applied to the analysis of pottery, x-ray diffraction techniques have been among the least used, and then usually to obtain qualitative information. Most analytic methods measure the relative abundance of chemical elements, but diffraction patterns give information on the crystalline substances in the pottery. In this study, attention is directed to the crystalline components of the temper rather than the clays or their derivatives. The method groups pottery according to the relative concentrations of such minerals as quartz, calcite, and the feldspars. Thus, success depends on reasonable consistency in the use of tempering materials by pottery makers at one time and place. I have examined a number of sherds from different sites in Iowa and Missouri supplied by Dale R. Henning, University of Nebraska. The results so far indicate that it is possible to group prehistoric pottery by a quantitative analysis of the x-ray diffraction pattern of the temper in the pottery.

Qualitative and Quantitative Analysis of Stacking Disorder in α-and β-SiC by X-ray Diffraction and Structure Modeling

1995 ◽  
Vol 410 ◽  
Author(s):  
Bogdan Palosz ◽  
Svetlana Stel'makh ◽  
Stanislaw Gierlotka
Keyword(s):  
Quantitative Analysis ◽  
Model Parameters ◽  
Qualitative And Quantitative Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Qualitative And Quantitative ◽  
Poisson Function ◽  
Diffraction Patterns ◽  
Computer Generation ◽  
Stacking Disorder

ABSTRACTA method of analysis of disordering in α- and β-SiC polycrystals by numerical modeling, and a simulation of X-ray diffraction profiles are presented. The diffraction patterns of nonperiodic structures were simulated for models of 2000 layer fragments of the structure. Computer generation of the models was based on the Poisson function describing the size distribution of the domains of basic polytypes and faults. The models were quantified by a set of input probability parameters describing relative frequencies of the occurrence of the domains of polytypes and faults. Implementation of a correlation parameter that characterizes coherence of sequential domains of a given polytype assures a good reproducibility of the simulated diffraction profiles obtained for the same set of the model parameters. Based on this method, a quantitative analysis of disordering in polycrystals of SiC annealed in the temperature range 1100–2200 °C was performed.

scholarly journals THE ICOSAHEDRAL PHASE OF Al63Cu25Fe12 SYSTEM

2019 ◽  
Vol 28 (1) ◽  
pp. 51-56
Author(s):  
Anastazia Melnik ◽  
Luciano Nascimento
Keyword(s):  
Chemical Elements ◽  
Stoichiometric Composition ◽  
Icosahedral Phase ◽  
Quasicrystalline Phase ◽  
Nominal Composition ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ideal Composition ◽  
Diffraction Patterns

The present work aimed to characterize the microstructure of the icosahedral phase (quasicrystalline phase-ϕ) of the system with stoichiometric composition of the quasicrystal Al63Cu25Fe12. The ternary alloy with nominal composition of Al63Cu25Fe12 was processed by mechanical alloying (MA) as a viable solid state processing method for producing various metastable and stable quasicrystalline phases. The structural characterization of the obtained samples was performed by X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM), while the elemental composition of the chemical elements Al, Fe and Cu were determined by X-ray spectroscopy technique of dispersive energy (EDS). According to the results of XRD, the diffraction patterns of Al63Cu25Fe12 showed the presence of β-Al(Fe, Cu) and λ-Al13Fe4 phases coexist with the thermodynamic ϕ-phase quasicrystalline. Finally, elemental analysis indicates that during alloy synthesis there is little variation of the ideal composition. The results indicate that alloys with high percentage of icosahedral phase can be obtained by casting in the air.

FULLPAT: a full-pattern quantitative analysis program for X-ray powder diffraction using measured and calculated patterns

2002 ◽  
Vol 35 (6) ◽  
pp. 744-749 ◽  
Author(s):  
Steve J. Chipera ◽  
David L. Bish
Keyword(s):  
Quantitative Analysis ◽  
Matrix Effects ◽  
Internal Standard ◽  
Solid Material ◽  
X Ray Diffraction ◽  
X Ray ◽  
Amorphous Phases ◽  
Quantitative Analysis Method ◽  
Diffraction Patterns ◽  
User Intervention

FULLPATis a quantitative X-ray diffraction methodology that merges the advantages of existing full-pattern fitting methods with the traditional reference intensity ratio (RIR) method. Like the Rietveld quantitative analysis method, it uses complete diffraction patterns, including the background. However,FULLPATcan explicitly analyze all phases in a sample, including partially ordered or amorphous phases such as glasses, clay minerals, or polymers. Addition of an internal standard to both library standards and unknown samples eliminates instrumental and matrix effects and allows unconstrained analyses to be conducted by direct fitting of library standard patterns to each phase in the sample. Standard patterns may include data for any solid material including glasses, and calculated patterns may also be used. A combination of standard patterns is fitted to observed patterns using least-squares minimization, thereby reducing user intervention and bias.FULLPAThas been coded into MicrosoftEXCELusing standard spreadsheet functions.

Reflection Electron Diffraction of Catalase

1975 ◽  
Vol 33 ◽  
pp. 672-673
Author(s):  
T. K. Chatterjee ◽  
J. A. Spadaro ◽  
R. W. Vook
Keyword(s):  
Electron Beam ◽  
Electron Diffraction ◽  
Preliminary Report ◽  
Water Vapor Pressure ◽  
High Energy ◽  
High Energy Electron ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffraction Patterns ◽  
Reflection Electron Diffraction

Matricardi et al. have shown that high energy electron diffraction patterns of unstained and unfixed catalase may be obtained with a high voltage TEM using a hydration stage and that without such a stage TED patterns could not be obtained. They showed that such patterns were observed only when the water vapor pressure in the vicinity of the catalase was greater than 90 percent of the equilibrium value. They attributed their results to the destruction of the crystallinity of catalase when it is vacuum dried. Similar results using X-ray diffraction techniques have been reported. Matricardi et al. also noted effects due to radiation damage, whereby the number of reflections observed using the hydration stage decreased substantially with electron beam exposure. In the present preliminary report, it is shown that electron diffraction patterns can be obtained from unstained and unfixed catalase even when the crystals are exposed directly to the vacuum of the TEM but under such conditions whereby the electron beam intensity is reduced by up to approximately two orders of magnitude from that usually obtained in normal TED work on a TEM.

scholarly journals Characterization in the icosahedral phase of the system Al63Cu25Fe12

2021 ◽  
Vol 24 (3) ◽  
pp. 1-5
Author(s):  
Luciano Nascimento ◽  
Anastasia Melnyk
Keyword(s):  
Chemical Elements ◽  
Stoichiometric Composition ◽  
Icosahedral Phase ◽  
Quasicrystalline Phase ◽  
Nominal Composition ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ideal Composition ◽  
Diffraction Patterns

The present work aimed to characterize the microstructure of the icosahedral phase (ɸ-quasicrystalline phase) of the system with stoichiometric composition of the quasicrystal Al63Cu25Fe12. The ternary alloy with nominal composition of Al63Cu25Fe12 was processed by Mechanical Alloying (MA) as a viable solid state processing method for producing various metastable and stable quasicrystalline phases. The structural characterization of the obtained samples was performed by X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM), while the elemental composition of the chemical elements Al, Fe and Cu were determined by the technique of X-ray spectroscopy by dispersive energy (EDS). According to the results of XRD, the diffraction patterns of Al63Cu25Fe12 showed the presence of β-Al (Fe, Cu) and λ-Al13Fe4 phases coexist with the thermodynamic ɸ-phase quasicrystalline. Finally, elemental analysis indicates that during alloy synthesis there is little variation of the ideal composition. The results indicate that alloys with high percentage of icosahedral phase can be obtained by casting in the air.

Evaluation of Freezing Methods by Low Temperature X-Ray Diffraction

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

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

Examination of Rabbit Fc Crystals

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

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

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