bluuebunny/crossref_metadata_2025_split huggingface dataset:
Some X-Ray Observations on the Oxidation Characteristics of Binary Niobium Alloys
Authors: Hiltz Ralph H. 
Published: March 2019

AbstractPresent knowledge of the effect of alloying on the oxidation characteristics of niobium is limited almost entirely to oxidation rate and oxygen diffusion rate data. In an effort to determine the mechanism by which alloying elements increase or decrease the oxidation rate of niobium, an x-ray study of niobium alloys was performed. Both x-ray diffraction and fluorescent studies were conducted on the base metal before and after oxidation, on the scale formed, and on the interface between the metal and the scale. From the data obtained, a definite description of the mechanism was not possible, but it appears that the Nb0 film between the metal and the Nb203 scale is the rate controlling factor. The elements Ti, Mo, Cr, W, and V which produce a substantial improvement in oxidation resistance effect the formation of a second oxide structure within the Nb0 film. All the elements which provide a measurable increase in oxidation have either a similar ionic size or a +3 valence state and in most cases have both. Elements not having a +3 valence state or similar ionic size, i.e., Cu, Mn, Si, and Zr, do not improve oxidation resistance, in fact Si and Zr act to eliminate the Nb0 film and the oxidation rate of these alloys is greater than pure niobium.
Determination of Uranium in Flotation Concentrates and in Leach Liquors by X-Ray Fluorescence
Authors: Smithson G. L. , Eager R. L. , Van Cleave A. B. 
Published: March 2019

AbstractX-ray fluorescence has been applied to the analysis of flotation concentrates obtained from pegmatitic uranium ores occurring in Northern Saskatchewan. It has been found necessary to use an internal standard such as strontium or yttrium. The time required for an analysis, as compared to that of conventional chemical or U.V. fluorescence methods, is considerably reduced and flotation pilot plant operations can therefore be more effectively controlled. The method has been extended to include the analysis of sulphate liquors obtained from the leaching of pegmatitic ores and their flotation concentrates. The amount of iron present in the samples is also determined by reference to the internal standard used for the uranium. This additional information is useful in assessing the efficiency of various flotation and leaching techniques.
X-Ray Spectrographic Determination of Uranium and Plutonium in Aluminum and Other Reactor Fuel Materials
Authors: Lambert Maurice C. 
Published: March 2019

AbstractSeveral instrument modifications are described including a shop-built turret mount which provides four water-cooled sample compartments, each accommodating samples up to 1.75 inches in diameter by 1.75 inches long.Sensitivity for detection of the elements throughout the Periodic Chart is discussed for several counters.Uranium and plutonium have been determined up to 20 w/o in metallic samples of aluminum alloys with a precision of ± one per cent in less than three minutes counting time. The determination of uranium dioxide in cryolite involved powder samples and the use of an internal standard. Uranium dioxide dispersions in bismuth metal were very heterogeneous; they were dissolved and precipitated to provide homogeneous, powders which were analyzed by measuring the intensity ratio of uranium and bismuth fluorescence.X-ray fluorescence has been used to measure aluminum cladding thickness over plutonium alloy cores. Precision is discussed in terms of cladding thickness, aperture size, and counting time. Thickness of 11 w/o and 14 w/o plutonium-aluminum and enriched uranium-aluminum cores in reactor fuel plates has been measured by X-ray absorption in the range 0.010 to 0.030 inch with a sensitivity of ± 0.00025 inch.
Recrystallization Studies of High Purity Aluminum Single Crystals
Authors: McCune Robert A. , Leighly H. P. 
Published: March 2019

AbstractThe two basic recrystallization theories, that of oriented growth and tliat of oriented nucleation, have been reviewed in light of data obtained from growth of single grains into strained single crystals of high purity (99.99%) aluminum. It appears that a compromise of these two theories would best explain the results obtained under this investigation. Basically, the proposed theory states that a stress is developed between coherent embryo nuclei and the strained matrix crystal. The relative orientation of the embryo nucleus and the matrix coupled with the residual stress in the strained matrix crystal will determine the magnitude of the stress between the embryo arid the matrix. When this stress is of sufficient magnitude, the coherent bonds between the embryo and the matrix will rupture and the embryo will become a nucleus which can then grow and consume the matrix.Competing with this process is the phenomenon known as polygonization. Partial relief of the residual stress in the sprained crystal takes place as polygonization occurs. This partial stress relief is often sufficient to prevent the formation of nuclei and the occurrence of subsequent recrystallization.
Applications of Optical and Electronic Dispersion to X-Ray Absorption-Edge Spectrometry
Authors: Dodd Charles G. 
Published: March 2019

AbstractThe applications of X-ray emission or fluorescent spectrography to chemical analysis have increased spectacularly in recent years, but little attention has been paid to the potentialities of X-ray absorption techniques. Monochromatic X-ray absorption-edge spectrometry, in particular, is most promising. The ultimate sensitivity of absorption-edge spectrometry probably will be less than that of fluorescent analysis, but this disadvantage may be outweighed by the convenience, economy, and absence of matrix effects with the former method. Both methods appear limited in application only to certain elements.A pulse height analyzer coupled with scintillation and proportional counter detection has been found to permit an increase in sensitivity of absorption-edge spectrometry, primarily because controlled window widths may be utilized in determining transmitted X-ray intensities with a sealer. Further work has led to the development of a new rapid, convenient technique known as “differential pulse amplitude distribution (PAD) peak height analysis.” Work carried out during the development of the new method is described.
The Universal Vacuum Spectrograph and Comparative Data on the Intensities Observed in an Air, Helium, and Vacuum Path
Authors: Miller D. C. , William Zingaro P. 
Published: March 2019

AbstractEquipment is described whereby comparative measurements were made on the relative absorption of air.helium, and vacuum for the softer radiations which are of interest in furthering the range of sensitivities of the X-ray spectrograph. Data on magnesium, aluminum, and silicon and shorter wavelengths are presented.
The Norelco Portable Spectrometer (Portospec)
Authors: Miller D. C. 
Published: March 2019

AbstractA light-weight portable X-ray spectrograph is described in some detail. The analyzing head, weighing only 18 lb, contains a goniometer, ratemeter, and Geiger counter detector. It also contains a special window-type X-ray tube with a gold target which has been developed specifically for this spectrograph, and which provides a very high efficiency of excitation of the sample. An associated power supply contains an rf source providing 40 kv at 60 μa together with the necessary voltages for the rectifier filaments, the X-ray filament, and the Geiger counter voltage. It will detect wavelengths from atomic number 23, vanadium, to atomic number 50, tin, and then using the L series from atomic number 58, cerium, to atomic number 92, uranium. Sensitivity and some applications are discussed.
The Establishment of A Q Rating Factor for Decorative Chromium Plate by X-Ray Fluorescence
Authors: Keesaer William C. 
Published: March 2019

AbstractProcedures and methods employed to develop anX-ray emission spectrometer technique for determining the quality of decorative chromium plate are presented. Individual plate quality factors and their significance are discussed:
1.Plate thickness2.Plate density3.Plate corrosion resistanceGeometric instrumentation changes to the General Electric XRD-5S spectrometer are detailed. These alterations have made it possible to take more complete advantage of the nondestructive nature of the fluorescent method, and have also yielded an increase in useful radiation intensity of 50%.The unsuccessful attempts to employ commercially plated Hull-cell-type test panels as “standards” are described, along with the satisfactory application of fabricated standards of vacuum vapor-deposited high-purity chromium, laminated to spectrographically pure nickel foils. The merits and limitations of the resultant “absolute purity — absolute density” standard curve are shown and are related to other measurement techniques and accelerated corrosion test data.
Count Distribution and Precision in X-Ray Fluorescence Analysis
Authors: Heinrich Kurt F.J. 
Published: March 2019

AbstractThe statistical fluctuations of photon counts arediscussedas a factor limiting the precision of the analytical result. Assuming a Poisson distribution, the theoretical standard deviation of the result can be calculated. While this prediction does not consider causes of variation other than the count statistics, it is useful in developing methods and checking instrument reliability. Practical examples using experimental results are given.
The Direct Determination of Vanadium and Nickel in Crude Oils by X-Ray Fluorescence
Authors: Lopp Victoria R. , Claypool C. G. 
Published: March 2019

AbstractA rapid method has been developed for the determination of vanadium and nickel in crude oils in concentrations above 5 ppm. Duplicate analyses for both nickel and vanadium require only one hour, and excellent precision is obtained. At a concentration level of 100 ppm of vanadium, the standard deviation is 3.1 ppm, and at a level of 30 ppm of nickel, the standard deviation is 1.6. The results are comparable to those obtained by spectrophotometric and optical emission spectrographic analysis.Conversion of the crude oils to greases by the addition of aluminum stéarate minimizes the usual difficulties of handling liquid samples in the conventional-geometry fluorescent X-ray spectrometer. Scattered tungsten emission lines from theX-ray tube serve as internal standards to correct for instrumental and matrix variations.A new sample tray that permits the insertion of four samples into the instrument at a time has been constructed. Each sample can be moved into position for analysis without opening the sample chamber, making it necessary to waitfor the helium to sweep the trapped air from the X-ray path only once for each four samples.
X-Ray Spectrographic Analysis of Manganese Nodules
Authors: Gordon George M. , McNely Donald J. , Mero John L. 
Published: March 2019

AbstractManganese nodules obtained from the ocean bottom are a vast potential source of minerals. These nodules, whose composition depend on their source, have an average composition of about 20% manganese, 14% iron, and 0.5% each of cobalt, nickel, and copper.X-ray spectroscopy was investigated as a method for the analysis of the nodules, and analytical control during the process of extracting and recovering the minerals.The basic borax fusion technique of Fernand Claisse (R. P, No. 327, Department of Mines, Quebec) was used. The influence of matrix elements was determined and corrections applied. The binary systems in borax were compared with the curves calculated from pure metals using the methods and calculations of Beattie and Brissey.The results indicate that the fusion method is sufficiently rapid and accurate for use in the control analysis of manganese nodules.
Differentiation of Several Related Ceramic Bodies by X-Ray Diffraction
Authors: La Forge Louis H. 
Published: March 2019

AbstractFor some vacuum tube work, it was desired to establish a reliable and moderately rapid means of differentiation among several related ceramic bodies, mostly among the high aluminas. Matured composition from a crystallographic standpoint was of primary interest; source and batch constituents were sought only as additional information for interpreting results on the matured ware.Since Al2O3 represented the major crystal phase in most bodies, the indicators of difference were the minor crystal phases. A number of X-ray diffraction techniques were tried, as were machines of different manufacture. Camera studies with powdered samples were generally ineffective. Useful data were obtained using the Geiger tube—goniometer setup with experimentally determined settings for sensitivity, circuit time constant, sweep rate, beam and receivingslitwidths, etc. Fixedposition peak-height counting was much slower, not practically better for peak-height determination, and introduced chances of missing peaks unless they were first determined by scanning and recording, thus further lengthening the analysis time considerably.Satisfactory results have been obtained on a number of the bodies of interest. Generally, those bodies which are not differentiated by the X-ray technique outlined are not markedly differentiated in the vacuum tube application.
X-Ray Methods for Detection of Lattice Imperfections in Crystals
Authors: Gerold Volkmar 
Published: March 2019

AbstractTwo methods are described for the detection of lattice imperfections of different kinds.1.Imperfections in Solid Solutions. Normal diffraction methods with monochromatized X-rays are applied to single crystals of supersaturated solid solutions, where preprecipitation states occur. The calculated intensity distribution for a one-dimensional model of clustering shows the influence of atomic distribution and lattice distortion. Results are given on the structure of clusters in aluminum-rich alloys.2.Detection of Dislocations in Nearly Ideal Crystals. A method first given by Barth and Hosemann is improved and used for the detection of dislocations in crystals of germanium. Use is made of the anomalously low absorption coefficient existing for X-rays which make the Bragg angle with a certain set of lattice planes going through a perfect crystal. The absorption is increased at points where the lattice planes are distorted by a dislocation line, and shadows from these lines can be seen on a photographic plate behind the crystal. The method gives information on the spatial distribution of dislocation lines and the direction of the Burgers vectors,
Precision X-Ray Stress Analysis of Uranium and Zirconium
Authors: Wooden B. J. , House Lt. E. C. , Ogilvie R. E. 
Published: March 2019

AbstractThe feasibility of using X-ray diffraction methods to measure residual stresses in uranium and zirconium (Zircaloy-2) was investigated. A precision method was developed for the determination of diffraction peak positions and the precision associated therewith. The statistical tables of Fisher and Yates were used to determine what order polynomial provided the best least squares fit within the known precision of the observed data. It was found that a second-order polynomial provided an adequate regression. With the aid of a desk calculator less than 5 min calculation time is required to determine the peak position to a precision of ±0.01°.The stress constant for uranium was determined to be 1308 ± 110 psi/0.01° shift in Δ2θ for copper radiation on the (116) planes at 2θ = 158.3°. The stress constant for Zircaloy-2 was determined to be 430 ± 1 psi/0.01° shift in Δ2θ for chromium radiation on the (10,4) planes at 2θ = 156.4°.
Crystallite Size and Particle Size Measurements on BeO Powders by X-Ray Methods
Authors: Bartram S. F. 
Published: March 2019

AbstractAs part of a study on the fundamental properties of BeO, the surface area, particle size, and crystallite size of BeO powders prepared from different source materials were measured. The results obtained by means of small-angle X-ray scattering and X-ray line-broadening have been compared with electron micrographs and surface area values by air permeability, nitrogen adsorption, and water-vapor adsorption.Small-angle scattering data were analyzed to yield particle size distribution curves as well as surface areas for various calcined BeO samples. Line-broadening measurements were made to determine mean crystallite dimensions of these same materials. By using both photographic film and automatic recording techniques, crystallite sizes from about 50 to over 5000 A were estimated. The rate of growth of BeO crystals from beryllium hydroxide, beryllium sulfate, and beryllium oxalate source materials has been followed by these complementary techniques.
Design and Applications of a Variable-Temperature Diffractometer Specimen Mount
Authors: Baun William L. 
Published: March 2019

AbstractA design is described for a variable-temperature diffractometer specimen mount developed internally in the Physics Laboratory of Materials Central. Temperature capability of 1600°C is achieved using Indirect radiation heating. Higher temperatures may be obtained by directly heating the sample. An adaptation allows operation at temperatures as low as −196°C and is useful for studying low-temperature phase changes and examining materials normally liquid at room temperature. The mount operates in vacuum or inert atmosphere. A full 180° 2θ scanning range is possible through the use of curved beryllium- or aluminum-foil windows. Realignment of the sample at temperature and under vacuum may be accomplished from four points around the front plate of the mount. Only two vacuum seals are used In this mount in addition to the window seal and thermocouple seals. Power for the mount is high current, low voltage, and is controlled by an automatic temperature regulator and sensing device which maintains an accurate preset temperature.Applications of variable temperature techniques on refractory metals, alloys, and compounds are shown, along with an example of low-temperature effects in materials normally liquid at room temperature.
X-Ray Absorption Measurement of Steam Voids in Water at High Pressures
Authors: Martin G. E. , Grohse E. W. 
Published: March 2019

AbstractX-ray absorption, having been earlier demonstrated to be a unique tool for the accurate measurement of density profiles within gas-fluidized solid systems such as those employed in the chemical and related industries, is being applied to the measurement of steam voids in water flowing through electrically heated rectangular stainless steel channels under conditions of pressure, temperature, flow rate, and heat flux corresponding to “local boiling” (subcooled water) as well as “bulk boiling” (saturated water) in the coolant channels of water-cooled nuclear reactors.A balanced dual-beam photometer system is employed. A dual-beam X-ray tube and two scintillation-crystal-photomultiplier-tube detector probes are mounted in a manner permitting remote-operated traversing of the test channel in the horizontal as well as vertical directions. The photomultiplier tubes are used in a difference circuit with one of the tubes monitoring the test channel and the other a remoteoperated reference wedge. The difference-measuring connection offers common made rejection so that any differential output Is due to a change in attenuation of the testchannel beam. This output is fed through a differential amplifier to a strip-chart recorder.With a test channel consisting of 0.020-in-thick stainless steel walls, backed by 0.062-in. beryllium windows for strength, void concentrations within a 0.250-in, thickness of water currently can be measured with an absolute accuracy of 2% or better (which is far superior to that obtainable with previous techniques) and further improvements in accuracy appear likely. The test channel is enclosed in a heavy steel housing with windows, permitting void measurements to be made at pressures up to 2000 psia.
Pulse-Height Selection in X-Ray Fluorescence
Authors: Heinrich Kurt F.J. 
Published: March 2019

AbstractPulse-height analysis is a valuable tool in X-ray fluorescence analysis, both for qualitative and quantitative purposes. The elimination of higher order interferences permits determinations that would otherwise be very difficult or impossible, The systematic application of pulse-height analysis in qualitative work greatly simplifies the interpretation of complex spectra. In certain cases one can apply nondispersive analysis, relying on the pulse-height analyzer alone for separating energy levels of X-ray photons. Technique and limitations of pulse-height analysis will be discussed.
The Effects of Operating Variables in the Application of Multielement Calibration
Systems for Fluorescent X-Ray Spectrographic Analyses of Mineral Samples
Authors: Salmon Merlyn L. 
Published: March 2019

AbstractA highly simplified multielement calibration systemfor semiquantitativeanalyses of mineral samples by fluorescent X-ray spectrography was discussed at the Eighth Annual Conference on Applications of X-ray Analysis. This system relates scattered radiation intensity (background) with peak intensity as measuredon a chart recording to determine concentrations of several elements in a sample.A continuation of the study reveals the effects of operating variables such as: (1) sample preparation and choice of sample type, (2) operating power and target choice of the X-ray tube, (3) collimation ratio, (4) goniometer scanning rate, (5) choice of method for measurement of background intensity, and (6) control and adjustment of detector, sealer-ratemeter, recorder, and other electronic circuits.The over-all effects of some operating variables are negligible owing to the compensatory nature of the calibration system. The net effects of others can be directly attributed to particular operating conditions, and these conditions can be controlled to achieve an optimum balance of effects to yield the desired results for accuracy, time required to complete the analyses, and other important requirements in the analyses of minerals.
Fluorescence Analysis of Trace Amounts of Hafnium in Zirconium Using a Silicon Crystal
Authors: Parks J.C. , Plackmann D.G. , Beyer G. H. 
Published: March 2019

AbstractThe proper choice of an analyzing crystal sometimes makes It possible to suppress second-order reflections which interfere with X-ray fluorescence analysis. Some of the problems associated with the analysis of small amounts of hafnium in zirconium, using a silicon crystal and a pulse-height analyzer, are discussed.
An Application of X-Ray Fluorescent Spectrography to Columbium Alloy Melting Practices*
Authors: Moroz D. , Fornwalt D. E. , Aconsky S. , Doyle J. , Clough W. R. 
Published: March 2019

AbstractTechniques were developed and statistically evaluated for the determination of both the homogeneity and the elemental compositions of columbium alloy ingots. X-ray fluorescent spectrography and automatic data handling systems are utilized. Sample preparation is discussed in detail from the consumable-electrode arc-melt process to the final physical form suitable for X-ray fluorescent spectrography. Arrangements of apparatus for obtaining, recording, processing, and interpreting data, with specific attention to limitations for various matrices, are treated at length.The method has been applied to specific cases with, for example, a correlation of the degree of variation of homogeneity of columbium alloy ingots with remelting practice. An attempt is made to provide a preliminary basis for determining the value of the technique as a possible means of quality control.