bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Simplified Procedure for Calculating Peak Position in X-ray Residual Stress Measurements on Hardened Steel
Authors: Koistinen D. P. , Marburger R. E. , Mitchell R. P. 
Published: March 2019

AbstractIn the measurement of residual stresses in hardened carbon steels by X-ray diffraction the principal difficulty encountered is determining the precise location of the broad diffraction lines. Christenson and RowlandM have proposed a workable technique, but it entails a complicated correction calculation. A simplified correction procedure, based on theoretical considerations, will be described which shortens the time required to obtain accurate data and cuts the time required for calculation to a fraction of that required for the previous method.It can be shown that the asymmetry of the broad diffraction lines in the back reflection region is largely due to 6 dependent intensity factors. Thus, the proposed correction procedure uses a multiplicative correction to peak intensity which includes all significant geometrical and absorption factors. The line position is then determined accurately as the axis of a parabola fitted to the corrected data. Since the data is taken in the vicinity of the peak, the time required to obtain accurate data is reduced and furthermore it is possible to determine residual stresses in as-quenched steel even though the structure is tetragonal.Examples of the type of stresses measured and the correlation between this new method and that of Christenson and Rowland will be presented.
Electrolytic Isolation and the X-Ray Study of Micro-constituents in Steels
Authors: Andrews Kenneth W. , Hughes Hugh 
Published: March 2019

AbstractThe identification of phases in solid steel specimens is subject to well known limitations. With suitable techniques, however, phases present in exceedingly small amounts can be isolated and identified. The work to be described is represented by three main stages.1.The techniques of isolation. The aim has been simplicity with the maximum efficiency of separation. Simple open and closed type cells are used and a few selected electrolytes for different conditions.2.The second stage is the identification of the separated particles. The X-ray photographs do, however, provide a considerable amount of other data which are often as important as the identity of the constituents. Thus, information can be obtained about the shape and size of particles and lattice spacing changes in solid solution phases. A supplementary determination of the solid solution content of the matrix is often useful.3.The third stage involves the interpretation of the results in relation to the strength and other properties of the steel or alloy. Here such questions arise as the effects of particular carbides or intermetallic phases, solid solution hardening and the times involved in various reactions and their relation to creep, etc.A number of examples are given and some limitations noted.
X-Ray Spectrographic Determination of Tantalum, Columbium, Iron, and Titanium Oxide Mixtures Using Simple Arithmetic Corrections for Inter element Effects
Authors: Mitchell Betty J. 
Published: March 2019

AbstractA method of specific arithmetic corrections for absorption and enhancement interelement effects has been developed, with particular reference to the quantitative determination of mixtures of tantalum, columbium, iron, and titanium oxides. The combined oxides of these elements are prepared chemically from liquid, powder, or metallic samples; weight percantages are determined by reference to calibration and intensity correction curves relating fluorescent intensity to concentration and sample matrix. Tantalum, columbium, iron, or titanium oxide from 0.01 to 100% concentration can be determined with a reproducibility of 1% of the amount present at the 50% concentration and 10% of the amount present at the 1 or 0, 1% level. X-ray analytical time required averages less than 10 minutes per determination. The corrections which have been established are universally applicable to combinations of these four oxides which may be obtained by chemical treatment from such materials as columbite or tantalite ores, tantalum or columbium metalSj and titanium alloys. The method of arithmetic corrections for interelement effects is general in nature and may be applied to the determination of other elements in complex matrices.
Rock Analysis by X-Ray Fluorescence Spectroscopy
Authors: Chodos Arthur A. 
Published: March 2019

AbstractOur laboratory has been interested in the use of the X-ray spectragraph for routine rock analysis within limited rock types. This paper is meant as a progress report and to indicate the direction of our work on amphibolites to others interested ill the problem of rock analysis.Even with the use of flow counters and pulse discriminators the intensities of the magnesium, aluminum and silicon peaks are quite low and most dilution techniques may not be used. The direct determination of major elements (except sodium) yields results directly comparable to the chemical results for potassium; manganese and titanium in the range from 0: 1 to 3% as the oxides. For iron (10-20%), calcium (8-12%) and silicon (45-52%) the accuracy is 2-3% but for each element occasional samples will be 5% from the chemical values. Aluminum and magnesium yield erratic results.The use of ratios between elements occurring in. the samples yields slightly improved accuracies. The use of a strong absorber such as tungstic acid (40% by weight) greatly improves the ratios for aluminum and magnesium., without appreciably affecting their intensities. By a combination of the direct and tungstic acid techniques it is possible to attain accuracies of 2-3% with analysis time of two hours. At present we are attempting a combination with an internal standard method to yield greater accuracy.
Micro-Analysis by X-Ray Absorption, Fluorescence, Emission and Diffraction Using Ultra-Fine X-Ray Sources
Authors: Cosslett V. E. , Duncumb P. , Long J. V. P. , Nixon W. G. 
Published: March 2019

AbstractFine focus X-ray tubes developed for projection X-ray microscopy can also be used for X-ray micro-analysis. Areas about 10 microns in diameter of thin sections have been analyzed by measuring differences in X-ray transmission, with particular reference to the determination of calcium in biological materials and in minerals. The high intensity of this X-ray point source has permitted micro-fluorescence analysis of similar small areas with high sensitivity and reasonable time. The same electron optical system has been used for micro-emission analysis of rock slices and mineral grains. By scanning the electron beam over the specimen surface and recording either the scattered electrons or the emitted X-rays, a two-dimensional picture can be displayed of the physical features or of the distribution of a particular element respectively. The analysis of a selected, volume of 1 cubic micron in the surface has been obtained by plotting the characteristic line emission spectrum with a crystal spectrometer and proportional counter. The sensitivity is 0. 1% or 10−1 gram. Micro-beam X-ray diffraction has also been used with a stationary X-ray source both for transmission and back reflection with a 10 minute exposure from a 10 micron diameter area.
Feasibility of the X-Ray Spectrograph as a Continuous Analytical Instrument for Process Control
Authors: McCune Robert A. , Mueller William M. , Dunton Pauline J. 
Published: March 2019

AbstractStudies have been made of the application of X-ray spectrography to continuous analysis for process control. To date the most widespread application of fluorescent X-ray spectrography to process control has been in measurement of plating thickness. Realizing that many other processes could use a method of continuous analysis of moving materials, these studies were undertaken.A modified tube housing and sample holder was constructed so that material could be passed through the X-ray beam, of a conventional X-ray spectrograph at various linear speeds. Detectability versus material speeds were studied for a number of elements in various mediums.Application of fluorescent X-ray spectrography as a continuous analytical tool looks very promising. Further studies on specific plant problems should provide useful and advantageous industrial applications of the basic information developed here.
On the Mechanism of Recrystallization of Aluminum
Authors: Weissmann Sigmund 
Published: March 2019

AbstractRecrystallization and grain growth of 99.998% aluminum were studied by methods combining metallographic techniques with x-ray microscopy and diffraction analysis. The recrystallked grains were shown to be the product of preferential subgrain growth whereby subgrains subtending large disoriciitation angles with respect to their neighbors exhibited the highest velocity of growth. The recrystallized grains emerging from the deformed matriv showed at first a high degree of lattice perfection, but incurred growth accidents during the growth process. Values for the mean strain-free energy of the deformed matrix surrounding the growing subgrains were obtained from the kinetics of subgrain growth.
Techniques for X-Ray Diffraction Studies of Radioactive Materials
Authors: Cummings W. V. , Gruber W. J. 
Published: March 2019

AbstractMany materials, both fissionable and non-fissionable, become very radioactive when subjected to nuclear radiations. This radioactivity results in a high background level in X-ray diffraction studies and becomes a limiting factor in an analysis of radiation damage. A description is given of special techniques that are used to minimize this background and produce optimum diffraction conditions. The radioactive intensity of irradiated X-ray specimens varies from levels that are only mildly troublesome to levels that are extremely hazardous to personnel. The diffraction methods employed at the various levels are explained. An example of the radioactive energy spectrum of a specimen is given to show the method of selecting the best operating conditions and techniques.
A Universal Detector for the X-Ray Spectrograph
Authors: Kiley William R. 
Published: March 2019

AbstractA detector arrangement has been developed which will give nearly 100% efficiency over the entire range of wavelengths normally used in X-ray spectroscopy, including radiation from Mg Kα. A description of this counter is given and data obtained on pulse height distribution and pulse amplitudes will be discussed. Results obtained with typical specimens will be shown.
Recent Developments in Fluorescent X-Ray Spectrographic-Absorptiometric Analyses of Mineral Systems
Authors: Salmon Merlyn L. 
Published: March 2019

AbstractFluorescent x-ray speorographic studies of mineral systems were begun in the Metallurgy Division of the Denver Research Institute in 1953. These studies were concerned with several techniques but the primary research emphasis was placed on a method involving conjunctive analyses by monochromatic x-ray absorptiometry and fluorescent x-ray spectrography.Experimental data for mineral systems with wide variations in matrix compositions exhibit departures from simple calibration curves relating intensity and concentration for an element in a series of samples analyzed by simple fluorescent x-ray spectrographic procedures.Absorptiometric measurements are made with a thin layer of the mineral sample as an absorption filter for the monochromatic x-rays emitted by the element in question. The results of these measurements provide information for improvement of the simple correlation of intensity and concentration by manipulation of the experimental data with various operations based on Beer's law of radiation absorption.The results of work at the Denver Research Institute indicated the feasibility of the fluorescent x-ray spectrographic-absorptiometric method and the current work is an extension of the study of basic fundamentals, mechanical factors and practical applications of the technique.
A Versatile 19-cm-Diameter Low-Temperature Debye-Scherrer Camera
Authors: Taylor A. 
Published: March 2019

AbstractThe camera was constructed to fill the need for a low-temperature instrument capable of yielding high spectral resolution and accurate lattice parameters. Specimen temperatures in the range -190 to 300°C are attainable.A special feature of the camera is the film holder which is split along the beam axis into two symmetrical halves and which can easily be removed from the base without disturbing the cooling system or the specimen. The specimenholderis mounted on a cross-slide to enable specimens of large radius to be rotated off-center with the beam at glancing incidence to their surface. Finally, diffraction patterns from large metallurgical samples may be obtained by removing one of the film holders and employing the apparatus as a “half camera.”Some applications of the camera to the thermal expansion of SiC and MnSe are described.
Intensities of the K, L, and M Spectral Lines for the Elements with Atomic Numbers 16 TO 92*
Authors: Campbell William J. 
Published: March 2019

AbstractLine intensity and background measurements were made on the K lines for the elements with atomic numbers 16 to 60, L lines for the elements above atomic number 42, and M lines for elements above atomic number 80. Three general classes of samples were investigated: (1) infinitely thick, (2) microgram deposits, and (3) thin layers.These studies show that longer-wavelength L radiation may be preferable to the K series lines from the same element in the range of elements with atomic numbers 42 to 60, In particular the Lα lines are more intense than the K series lines from Class 2 and 3 samples. With Class 1 samples the Lα lines are weaker than the K series but their line-to-background ratio is superior to the K series.M series lines show little promise for spectrochemical analysis except for elements with atomic numbers 90 to 92; for example, with uranium samples in Class 2 and 3, the very high line-to-background ratio of the UMβ1 line may have limited application.Elements with atomic numbers from 16 to 22 are more sensitive than expected due to the very high line-to-background ratios and the reduced collimation requirements in this longwavelength region.
Some Irradiation Effects in Nonmetallic Crystals
Authors: Wittels M.C. , Sherrill F.A. 
Published: March 2019

AbstractNonmetallic crystals with a variety of structures and chemical compositions have been exposed to fission spectrum neutrons in a core position of the Low Intensity Test Reactor (LITR), Oak Ridge, and examined by X-ray diffraction techniques. Wherever possible, single crystals were employed, and the neutron dosages ranged between 1019 and 1021 neutrons/cm2 at a temperature of approximately 85°C. In no case was a special technique used for examining radioactive materials because the problem of heavy induced radioactivity was greatly reduced by working withcrystals weighing a milligram or less. Both film and counter measurements were employed.
Influence of Goniometric Arrangement and Absorption in Qualitative and Quantitative Analysis of Powders by X-Ray Diffractometry
Authors: Leroux J. , Mahmud M. 
Published: March 2019

AbstractA theoretical approach of some factors influencing the intensity diffracted by a polycrystalline material at a definite Bragg angle has been confirmed by experimental data obtained with a high-angle Norelco diffractometer. The factors mainly considered are the focusing arrangement of the goniometer which delineates the geometric shape of the volume fraction of the sample being irradiated and the absorption of the latter.Tests have been performed (a) with quartz mixed in samples covering a large range of absorption coefficients, (b) with two different K radiations using copper and molybdenum targets, (c) with three different angles of beam divergence of 1, ½, and ¼°, respectively, and (d) with the sample packed and leveled in a copper grid with openings of about 350 μ. As this test with copper grids was to demonstrate that each opening was acting like a volume of sample irradiated by a beam of extremely small divergence (0.1°), it also shows that more accuracy in the measurement of the exact Bragg angle can be reached in these conditions as compared to that obtained with conventional sample holders.A general equation, suitable for qualitative and quantitative analysis when these factors have to be taken into consideration, is proposed.
The Application of X-Ray Diffraction to Medical Problems
Authors: Parsons Jonathan 
Published: March 2019

AbstractThe use of the X-ray diffraction Debye-Scherrer powder technique for the identification of crystalline material often found in pathologic tissue is discussed. Cases cited include: heart calcification, lung silicosis, thorium dioxide in liver and spleen, and granulomas of the skin and pericardium. The routine analysis of kidney stones using powder cameras as well as an X-ray diffractometer will be described.
The Use of Optical Transforms in Crystal-Structure Analysis
Authors: Hargreaves Arnold 
Published: March 2019

AbstractOptical transforms are of particular value In the earlier stages of crystal-structure determination; they enable trial structures to be tested rapidly and may indicate the nature of changes which will improve a postulated structure. The optical transforms are produced in a simple instrument called an optical diffractometer. The projected positions of the atoms in a postulated structure are represented by a set of holes punched in a mask, and the diffractometer produces the Fraunhofer diffraction pattern of the mask. The distribution of intensity in the optical transform is comparable, when sampled at suitable Intervals, with the distribution of intensity among the observed intensities in a particular zone of X-ray reflections. The use of optical transforms in the determination of crystal structures and in the study of imperfect structures will be illustrated by examples.
Use of X-Ray Spectrometer Data in Radial Distribution Analysis of the Diffraction Patterns for Amorphous Materials
Authors: Robson H. E. , Broussard L. 
Published: March 2019

AbstractPrevious radial distribution work which we have found reported in the literature has invariably been based on film technique. Our work is entirely based on X-ray spectrometer intensity measurements, Radial distribution (RD) patterns for silica gel and η-aluinina are presented and the correlation with accepted structures for these materials demonstrated. The advantages of spectrometer over film technique are discussed. The entire calculation problem has been programed for the IBM 650 computer, A difference technique which appears very sensitive to small structure changes is described and demonstrated for silica-alumina cracking catalysts. A procedure for identifying systematic errors in the RD pattern is presented.
A New High-Power Microfocus X-Ray Diffraction Unit
Authors: Whitcomb Peter B. 
Published: March 2019

AbstractThe Hilger & Watts microfocus X-ray diffraction instrument has been redesigned to provide a tube allowing up to three times the target loading of previous tubes. The line focus, 6 mm × 100 μ, increases the target loading to 50 kv dc, 10 ma. To accomplish this, a new high-power transformer is provided with a special demountable tube and anode assembly with suitable cooling provided. The original 40 μ and 100 μ tubes are interchangeable with the new tube. Considerable gains in performance with photographic methods are indicated, but more notable is the increase in resolution when the microfocus unit is used as a source of X-ray for a diffractometer. The diffractometer can now be operated under the same conditions as those required for a conventional tube but with the much higher resolution.
Counter Adaptor and Furnace for Weissenberg Camera*
Authors: Young R. A. 
Published: March 2019

AbstractA rugged and versatile counter adaptor for a Weissenberg camera is described. It has performed well in two years of daily use which has included collection of intensity vs. temperature data with conventional cold-stream techniques.Advantage has recently been taken of the adaptor design to mount, directly on the Weissenberg base, a furnace device which blows hot air along the crystal mounting axis. Crystal temperature may be held constant or easily varied over the range up to about 700°C, with no obstruction of the X-ray beams and no readjustment of the furnace position, while the entire zero layer and close-in upper layers are explored.
Measurement in the 10 to 100 Angstrom X-Ray Region*
Authors: Henke Burton L. 
Published: March 2019

AbstractThe results of recent work of the Millikan Laboratory of Physics on the physics and application of ultra s oft X-radiation s are summarized. These investigations include (1) the compilation of ultrasoft X-ray interaction coefficients. (2) the development of high-intensity, low-voltage X-ray tubes (100 to 1000 v), (3) the application of pulse-height analysis in flow proportional counter measurement of 10 to 100 A radiations, (4) a detailed study of the photographic action of the ultrasoft X-radiations, and (5) the application of these long wave length X-radiations to micromass and microchemical analysis by mïcroradiographïand total-reflection techniques.
The Spectra of Some Beta-Excited X-Ray Sources with the Multichannel Analyzer
Authors: Preuss Luther E. , Horn Helen , Keiser Thomas W. 
Published: March 2019

AbstractThree beta-excited X-ray source types (the compound, apposition, and mixture source) have been designed, and the photon spectra compared. Each source in a series was assembled using a single target element with the concentration of pure beta emitter held constant for the series. The apposition source was studied with varying target thicknesses. The compound sources were crystalline precipitates of molybdate and tungstate groups compounded with the nonearrier-free beta emitter. The mixture source consisted of a fine-milled target powder with the beta emitter adsorbed on it. Assay of the X-ray source emission has been done on the Radiation Instrument Development Laboratories (RIDL) lOQ-channel analyzer with a 3-in. Nal detector. Variation in the spectra exists between the source types of a series. Anomalous peaking occurs with the Sr90 MoO4 source emission at 29 key. The compound source, potentially productive, demonstrates poor characteristic spectra.
The Fundamentals of Quantitative Electron-Probe Microanalysis
Authors: Castaing R. 
Published: March 2019

AbstractEmission-concentration proportionality Is one of the main features of electronprobe mlcroanalysis. It can be interpreted by taking simultaneously Into account the Z/A factor of Webster's law of deceleration and the variation with atomic number of the backscattering ratio. The baclcscattering ratio itself can be deduced approximately from experimental distribution curves of thecharacteristicemisslonjejqpertments on copper-gold alloys show good agreement with the theoretical predictions. An important practical consequence is that regulation of the electron beam falling onto the specimen leads to better results than regulation of the current passing through it. The different corrections are discussed, with special reference to the fluorescence induced by the general continuous spectrum. The case of insulating materials is considered separately; preliminary experiments seem to show that their behavior is not essentially different from that of conducting materials.