X-Ray Fluorescence of Rock Samples as Applied to Geological Problems

1968 ◽  
Vol 22 (5) ◽  
pp. 420-422 ◽  
Author(s):  
Richard A. Laidley

Three methods of sample preparation of rock specimens have been evaluated for precision and accuracy. A fusion technique was found to give the best precision. Standard deviations (1 σ) using this method and expressed as percent of the amount present for several elements are: Al 0.83, Si 0.64, K 0.43, Ca 0.43, Mn 0.48, Fe 0.24. Three recent studies of compositional variation were performed on volcanic rocks. Analyses of samples from the Hopi Buttes, Arizona, on obsidian flows from Newberry Caldera, Oregon, and on igneous rocks collected from grids or linear traverses give data which, in each case, are useful in making significant interpretations about the geologic history of the rocks concerned. These examples illustrate the rapidity and high quality of quantitative chemical analyses which can be obtained by application of x-ray fluorescence analytical techniques.

PEDIATRICS ◽  
1952 ◽  
Vol 10 (5) ◽  
pp. 624-626
Author(s):  
ALBERT V. HARDY

THERE are admitted limitations in our clinical examinations. The history may be biased. Significant departures from the normal may not be revealed by expert inspection, palpation and auscultation. Even x-ray is of help only when tissues of varying density are involved. Hence more and more we have turned to the laboratory for reliable data. It is to the great credit of the laboratories that in our teaching centers the results have had that degree of reliability which developed in our students a feeling of complete confidence in reported laboratory findings. It is not our intention to question whether this degree of confidence was warranted, but it is our purpose to make some observations on the reliability of laboratory examinations available to most of us in the practice of our profession. If laboratory findings are not as reliable as we expect them to be, can they be made so? "Survey of the Accuracy of Chemical Analyses in Clinical Laboratories" by Belk and Sunderman has been quoted repeatedly. The Pennsylvania State Medical Society sponsored the study. The 59 laboratories which voluntarily participated were under the direction of pathologists and chiefly in hospitals. The quality of work of small laboratories operated by a technologist or performed by individual technicians in physicians' offices was not assessed. The findings, it is presumed, are the more favorable observations for laboratories of one state. Samples for check-testing were submitted to the participating laboratories and results were reported and evaluated without identification of the laboratory concerned. To illustrate, a glucose solution with 60 mg. of glucose per 100 cc. was submitted, the result was considered satisfactory if readings were within the range of 50 to 70 mg. Of the 52 cxaminations reported, 33 were satisfactory.


2010 ◽  
Vol 25 (2) ◽  
pp. 175-181 ◽  
Author(s):  
Patrick J. Parsons ◽  
Kathryn G. McIntosh

Lead poisoning is a preventable condition caused by exposure to environmental sources such as lead-containing dust or lead-painted consumer products. The history of lead poisoning prevention has been defined to some extent by the quality of the analytical methods available for lead measurements whether in environmental samples or biological tissues and fluids. The quality of blood lead methods has improved so greatly over the last three decades that we now know far more about the adverse health effects from low-level exposures. Recent evidence suggests that effects such as deficit in IQ occur below the current (periodically revised) U.S. CDC threshold of 10μg/dL, such that no safe threshold appears to exist for children. Improvements in analytical techniques have also had an impact on the environmental measurement quality, yet many environmental thresholds have remained unchanged for decades. In light of our current understanding of the adverse health effects at low levels of exposure, new thresholds for lead in children’s products have been introduced by the U.S. CPSC. The adequacy of current analytical techniques to detect lead accurately at the new, lower thresholds is questionable. XRF offers the advantage of being rapid and nondestructive compared to techniques such as AAS that require extensive sample preparation. However, the accuracy of handheld XRF determinations of lead in painted toys is generally limited. A brief comparative study on the performance of several analytical techniques for the determination of lead in toys is presented at the end of this paper.


2019 ◽  
Vol 23 (6) ◽  
pp. 73-82
Author(s):  
A. N. Tsed ◽  
A. V. Smirnov ◽  
A. К. Dulaev ◽  
A. Sh. Rumyantsev ◽  
A. N. Ananyev

BACKGROUND. The number of patients with end-stage renal disease is steadily increasing. One of the main complications arising from the disorders of calcium-phosphorus metabolism in patients on hemodialysis is various types of renal osteodystrophy. The frequency of pathological fractures among patients receiving renal replacement therapy is twice as high as in the general population. The prevalence and structure of injuries, especially the diagnosis of injuries of the musculoskeletal system in hemodialysis patients, are not well understood. THE AIM: to determine the prevalence and structure of injuries and the consequences of pathological injuries of bones and joints undergoing hemodialysis in Saint-Petersburg. To achieve this goal, the authors developed a special questionnaire, consisting of 4 blocks, including 32 questions.PATIENTS AND METHODS. An analysis of questionnaires of 798 patients from 15 hemodialysis centers of Saint-Petersburg was carried out.RESULTS. A number of problems were identified, such as insufficient coverage of patients not only with specific instrumental examination methods (MSCT, MRI), but also with radiographic ones. Satisfaction with quality of life and physical activity was noted in less than half of patients. 46.4% had a history of fractures and injuries, while the proportion of operated patients was half that, which indicates the need for more active work of hemodialysis centers with city hospitals with traumatology and orthopedic departments.CONCLUSION. Patients on HD require regular x-ray examination and densitometry to detect pathological damage to bones and joints. Based on the results of these studies, it is advisable to consult a traumatologist at least 1 time per year.


1963 ◽  
Vol 65 (12) ◽  
pp. 251-314 ◽  
Author(s):  
M. J. O'Hara ◽  
F. H. Stewart

SynopsisGarnetiferous peridotite masses which occur among gneisses in the Tafjord district of Norway are cold intrusions emplaced as crystalline rocks late in the metamorphic history of the region. No relationship other than similarity of mineral facies can be established between the peridotites and the eclogite bodies in the surrounding gneiss. Chemical analyses of twelve olivines, fourteen orthopyroxenes, nine chrome diopsides, nine garnets, three amphiboles and two rocks are presented, representing material from the Tafjord and Almklovdalen districts of Norway, a garnetiferous peridotite mass near Bellinzona, Switzerland, and the garnet-peridotite inclusions in the kimberlite pipes of South Africa. Optical and X-ray data for the analyzed and some unanalyzed assemblages are also presented. The mineral assemblages of these rocks are compared with each other, and with data from the peridotites of layered tholeiitic intrusions, alpine-type peridotites and the peridotite nodules in basalts. The garnet-peridotites of Norway, Switzerland and South Africa are believed to be little altered fragments of the mantle, whereas the peridotite nodules in basalts and the alpine-type peridotites are believed to be of igneous origin. Examination of the distribution of cations between the coexisting phases suggests that there are too many variables to permit a reliable interpretation of the results.The orthopyroxenes from the garnetiferous peridotites are not rich in A1203, contrary to expectations based upon recent experimental work.


Author(s):  
Bruce Trigger

Historical works dealing with archaeology have been written to entertain the public, commemorate important archaeologists and research projects, instruct students in the basic concepts of the discipline, justify particular programmes or ideas, disparage the work of rivals, and, most recently, try to resolve theoretical problems. These studies have taken the form of autobiographies, biographies, accounts of the development of the discipline as a whole, investigations of specific institutions or projects, and examinations of particular theories and approaches. They have used the analytical techniques of intellectual and social history and sought to treat their subject objectively, critically, hermeneutically, and polemically. Over time, historical studies have become more numerous, diversified, and sophisticated. Histories of archaeology are being written for all parts of the world, and in a growing number of countries, a large amount of material is being produced at local as well as national levels. There is no end in sight to the growing interest in this form of research. The history of archaeology has been written mainly by professional archaeologists, who have no training in history or the history of science, and by popularizers. Only a small number of these studies have been produced by professional historians. Archaeology has attracted little attention from historians of science, despite its considerable interest to philosophers of science. This lack of interest is hard to understand since the difficulties inherent in inferring human behaviour from archaeological evidence make archaeology an ideal discipline for addressing many of the issues of objectivity that are currently of interest to historians of science. The earliest use of the history of archaeology appears to have been for didactic purposes. In the mid-nineteenth century, the physicist Joseph Henry, the first secretary of the Smithsonian Institution, sought to purge American archaeology of useless speculation and to encourage an interest in factual research. To do this, he commissioned Samuel F. Haven, the librarian of the American Antiquarian Society, to write a critical historical review of studies of American prehistory titled Archaeology of the United States (1856). To improve the quality of American archaeology, Henry also published reports on developments in the discipline in the Annual Report of the Smithsonian Institution, which was widely distributed in North America.


1993 ◽  
Vol 03 (03) ◽  
pp. 187-214 ◽  
Author(s):  
J.S.C. McKEE

Studies of particle induced X-ray emission (PIXE) have been widespread and detailed in recent years and despite the fact that most data obtained are from low energy 1–3 MeV experiments, the value of higher energy proton work with its emphasis on K X-ray emission has become more marked as time has progressed. The purpose of this review paper is to outline the history of analysis using high energy protons and to compare and contrast the results obtained with those from lower energy analysis using more firmly established analytical techniques. The work described will concentrate exclusively on proton induced processes and will attempt to outline the rationale for selecting an energy, greater than 20 and up to 70 MeV protons for initiating particles. The relative ease and accuracy of the measurements obtained will be addressed. Clearly such X-ray studies should be seen as complementing low energy work in many instances rather than competing directly with them. However, it will be demonstrated that above a Z value of approximately 20, K X-ray analysis using high energy protons is the only way to go in this type of analysis.


2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Qing Wu ◽  
Meret Hauldenschild ◽  
Benedikt Rösner ◽  
Tiziana Lombardo ◽  
Katharina Schmidt-Ott ◽  
...  

AbstractIn the history of medieval gilding, a common view has been circulated for centuries that the substrate colour can influence the visual appearance of a gilded surface. In order to fully understand the correlation between the gilding substrate and the colour appearance of the gold leaf laid above, in this paper (Part I) analytical techniques such as colorimetry and interferometric microscopy are implemented on models made from modern gold leaves. This study demonstrates that the substrate colour is not perceptible for gold leaf of at least 100 nm thickness, however the surface burnishing can greatly alter the visual appearance of a gold surface, and the quality of the burnishing is dependent on the substrate materials. Additionally, surface roughness and texture of the substrate can play supplementary roles, which can be visually observed through digital microscopy and quantified through interferometric microscopy. The findings in this paper will form the basis for the study of gold leaf samples taken from medieval European gilded sculptures in Part II.


2020 ◽  
Author(s):  
Qing Wu ◽  
Meret Hauldenschild ◽  
Benedikt Rösner ◽  
Tiziana Lombardo ◽  
Katharina Schmidt-Ott ◽  
...  

Abstract In history of medieval gilding, a common view has been circulated for centuries that the substrate colour can influence the visual appearance of a gilded surface. In order to fully understand the correlation between the gilding substrate and the colour appearance of the gold leaf laid above, in this paper (Part I) analytical techniques such as colorimetry and interferometric microscopy are implemented on models made from modern gold leaves. This study demonstrates that the substrate colour is not perceptible for gold leaf of at least 100 nm thickness, however the surface burnishing can greatly alter the visual appearance of a gold surface, and the quality of the burnishing is dependent on the substrate materials. Additionally, surface roughness and texture of the substrate can play supplementary roles, which can be visually observed through digital microscopy and quantified through interferometric microscopy. The findings in this paper will form the basis for the study of gold leaf samples taken from medieval European gilded sculptures in Part II.


1973 ◽  
Vol 39 (303) ◽  
pp. 289-296 ◽  
Author(s):  
M. Nawaz Chaudhry ◽  
R. A. Howie

SummaryChemical analyses of sixteen lithium-aluminium micas are presented along with their optical, physical, and X-ray data. Compositional variation, substitution relations in structural positions, and octahedral occupancy are discussed. The 2M2 structural types are found to crystallize in volatilerich low-temperature environments whereas the 1M polytypes occur in comparatively volatile-poor and higher-temperature environments. Variation diagrams have been constructed to show the relationship between octahedral sites occupied by and refractive indices and specific gravities.


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