New Data on Sources of Obsidian Artifacts from Tikal, Guatemala

1990 ◽  
Vol 1 (1) ◽  
pp. 71-80 ◽  
Author(s):  
Hattula Moholy-Nagy ◽  
Fred W. Nelson
Keyword(s):  
Optical Characteristics ◽  
Optical Variability ◽  
X Ray ◽  
Xrf Analysis ◽  
Artifact Type ◽  
Lowland Maya

AbstractIn 1984, 29 obsidian artifacts and an unworked nodule from Tikal were attributed to source by visual means and then analyzed by X-ray fluorescence (XRF). We conclude that the considerable within-source optical variability of gray Mesoamerican obsidians makes visual sourcing unreliable at present, although a corpus of descriptions of the optical characteristics of obsidian may eventually provide a way to exclude possible sources. The XRF analysis identified two additional central Mexican sources, bringing to six the number of Mexican obsidian sources represented at Tikal; failed to provide a secure identification for the nodule; supported the succession of Guatemalan obsidian sources utilized by the Southern Lowland Maya previously proposed by Nelson; and suggested other correlations between source, artifact type, and archaeological context.

ANALYSIS OF MULTI-ELEMENT POWDERS AND SOLUTIONS OF METALS WITH A PYROELECTRIC X-RAY GENERATOR

2005 ◽  
Vol 15 (01n02) ◽  
pp. 19-25 ◽  
Author(s):  
TETSUYA KOYAMA ◽  
JUN KAWAI
Keyword(s):  
Low Power ◽  
Background Level ◽  
Solid Samples ◽  
Portable Xrf ◽  
X Ray ◽  
Metal Elements ◽  
Xrf Analysis ◽  
Liquid Samples

Applications of X-ray fluorescence (XRF) analysis to solid and liquid samples with a pyroelectric X-ray generator are described. The X-ray generator is driven by a 9 V dry electric battery and small dimensions. It enables compact and portable XRF spectrometer. It has disadvantages in low power and periodically changing X-ray flux. Measured solid samples are briquettes from powdery oxides of Ti , V , Cr , Mn , Fe , Co , Ni and Cu , and sulfide of Zn . Each sample is prepared to contain equal molar metal elements. Liquid samples are solutions of Fe , Cr , Zn , Pb , Bi , Cd . K α and K β lines of all metals in solid samples are detected. Although background level was relatively high for liquids, all metals in the measured samples were detected within 70 seconds, except for Cd . The capability of XRF with the pyroelectric X-ray generator is discussed.

scholarly journals X-ray/UV/optical variability of NGC 4593 with Swift: reprocessing of X-rays by an extended reprocessor

2018 ◽  
Vol 480 (3) ◽  
pp. 2881-2897 ◽  
Author(s):  
I M McHardy ◽  
S D Connolly ◽  
K Horne ◽  
E M Cackett ◽  
J Gelbord ◽  
...  
Keyword(s):  
Optical Variability ◽  
X Rays ◽  
X Ray

scholarly journals Accuracy improvement in XRF analysis for the quantification of elements ranging from tenths to thousands μg g−1 in human tissues using different matrix reference materials

2020 ◽  
Vol 35 (12) ◽  
pp. 2920-2927
Author(s):  
Jorge Machado ◽  
Patrícia Miguel Carvalho ◽  
Ana Félix ◽  
Delfin Doutel ◽  
José Paulo Santos ◽  
...  
Keyword(s):  
Quantitative Determination ◽  
Reference Materials ◽  
Fluorescence Spectrometry ◽  
Human Tissues ◽  
Accuracy Improvement ◽  
External Calibration ◽  
X Ray ◽  
Xrf Analysis ◽  
Calibration Approach

In this work, we aim at achieving the most accurate quantitative determination of elements in human tissues by means of X-ray fluorescence spectrometry using the external calibration approach.

scholarly journals Correlated X-ray/optical variability in the quasar MR 2251−178

2008 ◽  
Vol 389 (3) ◽  
pp. 1479-1488 ◽  
Author(s):  
P. Arévalo ◽  
P. Uttley ◽  
S. Kaspi ◽  
E. Breedt ◽  
P. Lira ◽  
...  
Keyword(s):  
Optical Variability ◽  
X Ray

Soil Heavy Metal Pollution along Subin River in Kumasi, Ghana; Using X-Ray Fluorescence (XRF) Analysis

2010 ◽  
Author(s):  
K. Kodom ◽  
J. Wiafe-Akenten ◽  
D. Boamah ◽  
Melissa Denecke ◽  
Clive T. Walker
Keyword(s):  
Heavy Metal ◽  
Metal Pollution ◽  
Heavy Metal Pollution ◽  
X Ray ◽  
Soil Heavy Metal ◽  
Xrf Analysis
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