bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Debye Temperature of Carbonyl Iron
Authors: Gazzara Charles P. 
Published: March 2019

AbstractThe Debye characteristic temperature, θ, of carbonyl iron has been determined as being between 433 and 445°K at an ambient temperature of 310°K from an X-ray diffraction study utilizing both monochromatlzed and filtered radiation by both stationary and scanning slit methods.In computing θ, several factors have been taken into consideration; the diffracted integrated intensities have been corrected for temperature diffuse scattering (TDS); the temperature gradient through the specimen was found to be critical and given as 160°K/in. at 95°K; corrections for the temperature dependence of θ have been made; and extinction effects were investigated, and results contrary to those of U'lna, Krltskaya, and Kurdyumov have been found.The TDS corrected values for static and dynamic atomic displacements are also given.
X-Ray Studies in the Ti-O System*
Authors: Bright Norman F. H. 
Published: March 2019

AbstractX-ray diffraction studies have revealed that a titanium oxide with an NaCl-type structure is stable over a wide range of nonstoichiometric compositions, both above and below the 1:1 Ti/O atomic ratio. Attempts to prepare a strictly stoichiometric TiO as a single phase have revealed a marked tendency for such a composition to disproportionate into two nonstoichiometric “TiO”-type structures of variable composition, whereas nonstoichiometric compositions can be readily prepared under similar conditions as single, well-crystallized phases.The oxide Ti3O5, which forms a constituent of the titanium-bearing slags produced in ilmenite smelting, has been prepared as a pure compound in two different crystalline forms, both monoclinic in structure, but one being very close to the orthorhombic pseudobrookite, Fe2O3 · TiO2, or ferrous dititanate, FeO · 2TiO2 structure. This “dititanate” form inverts to the other monoclinic form at high temperatures. Single crystals of the latter monoclinic form are readily made. The studies of the “dititanate” form have been restricted to powder diffraction work, since it inverts to the other form after melting. The two forms show different oxidation behaviors,
A New Commercial X-Ray Projection Microscope*
Authors: Poen Ong Sing 
Published: March 2019

AbstractA recently developed Dutch commercial projection X-ray microscope will be described. The principal features are: simplified focusing by using reflected electrons, four different target materials exchangeable during operation, and hlnocular viewing of either the specimen itself or the fluorescent image. The specimen and film chamber is evacuated and the voltage is variable between 5 and 20 kv. Some results will be shown.
Industrial Applications of X-Ray Methods for Measuring Plating Thickness
Authors: Zimmerman R. H. 
Published: March 2019

AbstractCalibration procedures and data are presented for plating thickness measurements of gold, silver, tin, and nickel on copper, brass, and steel basis metals. Both emission and absorption techniques are described, and examples are given of measurements on thicknesses from 10 to 600 millionths of an inch. The use is shown of masking and integrating techniques for curved or unusual shapes.For the special problem of duplex platings, which have two metals each varying in thickness, the Kα/Kβ absorption ratio and the Lα/Lβ emission ratio are compared with conventional absorption and emission techniques.Optical and chemical determinations are shown to be less precise as well as considerably slower than X-ray measurements on the same piece. Examples are given of the use of X-ray measurements to study fundamentals of plating processes, such as barrel-plating thickness distributions and variation of thickness across a surface, as well as to study processes such as wear or porosity.
Routine Crystallite-Size Determination by X-Ray Diffraction Line Broadening
Authors: Rau R. C. 
Published: March 2019

AbstractIncreasing interest in the sintering characteristics of various ceramic materials has resulted in the need for a knowledge of the crystallite sizes of many constituent ceramic powders. Standard X-ray diffraction line-broadening techniques have been utilized to determine these crystallite sizes. This paper presents a general review of the theory of line broadening as a means of measuring crystallite size and gives the methods and modifications used to perform this type of analysis rapidly and on a routine basis.Four modifications have been used in the determination of crystallite size routinely by X-ray line broadening. These methods are (1) a graded set of powder photographs, (2) a computer program to calculate sizes from diffractometer data, (3) a set of crystallite-size curves for a given material for use with diffractometer data, and (4) a standard set of curves to use with diffractometer data for any strain-free materials. The preparation, use, and limitations of each of these methods is presented.
Selected Applications of High-Temperature X-Ray Studies in the Metallurgical Field
Authors: Goldschmidt H.J. 
Published: March 2019

AbstractHigh-temperature X-ray powder photography has proved of great value in many directions in the metallurgical field. Some of the successes achieved and problems encountered by the author and other investigators using an established-type camera (British Unicam) for temperatures up to 1400°C will be discussed. This will be by way of specific case histories, chosen both for their own scientific interest and to illustrate the techniques employed. The applications concern phase transformations and the measurement of coefficients of thermal expansion in iron and steels, as well as in some nonferrous metals and inorganic compounds.
The Application of X-Ray Diffraction at Elevated Temperatures to Study the Mechanism of Formation of Sodium Tripolyphosphate
Authors: Moore E. L. , Metcalf J. S. 
Published: March 2019

AbstractHigh-temperature X-ray diffraction techniques were employed to study the condensation reactions which occur when sodium orthophosphates are heated to 380°C. Crystalline Na4P2O7 and an amorphous phase were formed first from an equimolar mixture of Na2HPO4·NaH2PO4 and Na2HPO4 at temperatures above 150°C. Further heating resulted in the formation of Na5P3O10-I (high-temperature form) at the expense of the crystalline Na4P4O7 and amorphous phase. Crystalline Na5P3O10-II (low-temperature form) appears after Na5P3O10-I.Conditions which affect the yield of crystalline Na4P2O7 and amorphous phase as intermediates and their effect on the yield of Na5P3O10 are also presented.
A Simple Multielement-Calibration System for Analysis of Minor and Major Elements in Minerals by Fluorescent X-Ray Spectrography
Authors: Salmon Merlyn L. 
Published: March 2019

AbstractTechniques of mineral analysis by fluorescent X-ray spectrography can generally be classified on the basis of (1) extensive sample preparation and simple instrumental examination, (2) simple sample preparation and extensive instrumental examination, (3) extensive processes for both, or (4) simple processes for both major phases of the technique. The latter type of technique is usually the most commensurate with the concept “maximum information with minimum effort.”Suitable analytical results with multielement calibration systems for random mineral samples can be obtained if there are valid considerations of the relevant absorption and enhancement effects or if the systems are based on general procedures to minimize absorption and enhancement effects. Preliminary investigation indicated that control of sample mass and use of thin films of the mineral sample is a convenient and simple method of minimizing absorption and enhancement effects.Successful application of thin-film samples with known masses in a multielement calibration system is highly dependent upon details of sample preparation and comprehensive studies of these details will be discussed.The calibration system is suitable for the determination of minor and major concentrations in the sample, but it is not recommended for determination of trace concentrations.
Precision of X-Ray Emission Measurements in the Determination of Low-Alloy Steels with an X-Ray Spectrograph*
Authors: O'Neil Robert L. , Neuhardt John B. , Shulhof William P. 
Published: March 2019

AbstractA large amount of data has been treated statistically to determine daily and long-range variations which occur when replicate determinations are made on low-alloy steel samples. The experiment reported here was designed and run to evaluate the results obtained using an RCA Siemens X-ray spectrograph. As part of a quality-control method for the analysis of low-alloy steels, it was desirable to know the confidence limits for within-day and day-to-day replication. This paper reviews the results of this study and represents an outline of future work planned.
The X-Ray Spectrographic Analysis of Thin Films by the Milliprobe Technique
Authors: Sloan Robert D. 
Published: March 2019

AbstractFrequently it is desirable to perform an X-ray spectrographic analysis on an area of a specimen which is considerably smaller than that normally irradiated in bulk-production spectrographs. Ideally, one would turn to an electron-beam microanalyzer for this type of analysis. Unfortunately, there are few of us who can justify the expenditure necessary to equip our laboratories with this instrument. Therefore, a compromise measure has been arrived at which permits the analyst to examine an area many magnitudes smaller than that obtainable from production spectrographs and many magnitudes less expensive than that encountered in electron-probe microanalyzer instrumentation.
Equipment for Beam Scanning and Step Scanning in Electron-Probe Analysis
Authors: Wittry David B. , Fitzgerald Ray 
Published: March 2019

AbstractA versatile beam-scanning system has been developed for use with the Electron Microprobe X-ray Analyzer manufactured by Applied Research Laboratories, Inc. It provides for the display of X-ray intensities from any of three spectrometers, three nondispersive detectors (either counters or scintiallation counters), as well as the current collected by the target or the current backscattered by the target. The electrostatic deflection system does not interfere with the use of the optical-viewing system and provides a maximum scanning area of only slightly less than field of view of the optical-viewing system.A stepping motor, controlled from the readout console, has also been developed which permits automatic point-by-point analysis of a specimen with minimum operator attention. In the use of this attachement, measurements may be made for fixed time, fixed charge, or fixed counts (integrated intensity) at each point. As a result, the step-scanning motor facilitates accurate measurement of one-dimensional concentration fluctuations and is particularly useful for phase identification and studies of diffusion and segregation.
The X-Ray Investigation of Preprecipitation in Supersaturated Solid Solutions
Authors: Lutts A. 
Published: March 2019

AbstractThis paper briefly traces the study of the preprecipitation or cold-aging stage of the decomposition of supersaturated solutions by means of diffuse scattering of X-rays.This part of the overall precipitation process is of considerable practical as well as theoretical interest because it is during preprecipitation that changes in many physical and mechanical properties take place without the formation of a precipitate phase.Examples will be given to show the types of zones encountered during this stage in various age-hardening alloys. These will attempt to illustrate the contribution which the study of diffuse scattering of X-rays, guided by present-day concepts of crystal imperfections, has made toward a better understanding of the precipitation process in alloys.
Recent Developments in the Measurement of Orientation in Polymers by X-Ray Diffraction
Authors: Wilchinsky Zigraond W. 
Published: March 2019

AbstractFrom pole figure data, the orientation of a crystallographic direction R in any reference direction Q in a sample can be quantitatively expressed by the average <cos2σ>, where σ is the angle between Q and R in a crystal. In general, <cos2σ> can be evaluated in terms of the experimental averages <cos2ϕhkl> whereϕhkl is the angle between Q and the normal to the (hkl) planes. The number of independent <cos2ϕhkl> measurements needed varies from one to five depending on the crystal system, hkl indices, and other factors discussed. Experimental techniques found useful for measuring <cos2φ> are described.
Continuous Determination of Zinc Coating Weights on Steel by X-Ray Fluorescence
Authors: Dunne James A. 
Published: March 2019

AbstractThe measurement of the area density of zinc coatings on steel by X-ray fluorescence is considered from an instalment design point of view. Each of the two general approaches, i.e., measurement of the attenuation of the iron emission line by the zinc coating and measurement of the sine emission line has limitations. Calculations indicate that contrast requirements are best satisfied by the iron attenuation technique in the coating weight interval 0.2-1.2 oz/ft2 per side. Experimental data collected on galvanised and zinc foil samples are presented in support of this contention. Conversely, advantages in the application of the zinc emission method to very thin zinc coatings are pointed out. Spectral resolution is discussed in terms of the ultimate precision and range of coating weight measurements. For the iron attenuation method, it is concluded that a black plate to infinite zinc intensity ratio of approximately 500 permits reasonably precise measurement of zinc foil coating weights in the vicinity of 1.2 oz/ft2 per side. This requirement can be met through the use of a LiF monochroraator crystal and 5 in. of effective 0.020-in. flat plate collimation.
X-Ray Spectrographic Analysis of Rare Earths in Yttrium-Iron Garnet Powders
Authors: Lloyd J. C. , Kuptsis J. D. 
Published: March 2019

AbstractAnalysis schemes for eleven rare earths (Ce, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, Yb) taken singly in Y-Fe garnet powders are presented. Straight-line calibrations result in all cases, usually over a range from below 0.5 wt.% to better than 6 wt.%. Errors were held to ±5-10% even using extraordinarily simple sample preparation techniques. Data are presented relating to the effects of particle size and sample preparation on precision and accuracy of the resulting analysis.
Absorption Effects in X-Ray Fluorescence Measurement of Elements in Oil
Authors: Gunn E. L. 
Published: March 2019

AbstractThe influence of absorption effects in measuring elements in petroleum oil by X-ray fluorescence can, under certain circumstances, be predicted approximately from theory. Exact information on specific systems and instrumental conditions must practically be provided by experiment, however. The influence of absorption on fluorescent intensity under specific conditions of interest has been studied from three viewpoints; varying the depth through oil of a solid elemental specimen, varying the depth of a solution containing the element dissolved in oil, and varying the amount of the dissolved element in oil over a broad range in concentration. The group of elements selected for study illustrate characteristic fluorescent radiations often1 measured from oil. The experimental results are expressed graphically and are compared between elements as well as with theory. The results have analytical implications which pertain to the quantitative determination of elements in oil by X-ray fluorescence.
Particle Size and Mineralogical Effects in Mining Applications
Authors: Bernstein F. 
Published: March 2019

AbstractA relationship is derived between X-ray intensity and particle size for a minor constituent in a powder sample. Theoretical and experimental curves are compared for several elements which are of importance in mining applications. Based upon these curves, some general guides are established relating to a method of predicting the particle size required for a given application. It is also shown that the relative intensity of a minor constituent is independent of the absorption coefficient of the matrix, if the particle size of the matrix is constant. Mineralogical effects, which relate to the occurrence of an element in two or more forms of chemical combination, are discussed and several examples in mining applications are cited.
A Systematic Method for Indexing Spots of Single Crystals in Laue X-Ray Photographs
Authors: Konnan Y. A. 
Published: March 2019

AbstractThe determination of the orientation of a single crystal by Laue X-ray photographs is dependent on the identification of the indices of the spots. At the present time, the determination of indices is done by various methods, none of which is entirely systematical. A method for establishing the indices of the spots which avoids a trial-and-error approach is described here. The method is graphical, uses a specially compiled table of erystallographic angles and is not dependent on the complexity of the structure of the crystal or its symmetry. An example of the cubic system is included. With more complex crystal structures the method becomes very laborious and the help of computer methods is suggested.
X-Ray Diffractometric Examination of Low-Temperature Phase Transformations in Single-Crystal Strontium Titanate
Authors: Lytle Farrel W. 
Published: March 2019

AbstractThe lattice parameters of single-crystal SrTiO2 were determined by X-ray diffraction as a function of temperature from 4.2 to 300°K. Three significant regions were found: from 65 to 110°K a tetragonal modification, exists (c/a = 1.00056); from 35 to 55°K, line splitting consistent with orthorhornbic symmetry was observed, and at 10°K an anomalous maximum in the lattice parameter vs. temperature curve was found which suggested a third structure transformation. In the tetragonal region (at 78°K) the formation of a domain structure was observed with a polarising microscope. The low-temperature X-ray technique and X-ray cryostat are described.
Instrumental Developments for Electron Microprobe Readout
Authors: Heinrich Kurt F. J. 
Published: March 2019

AbstractWhile conventional X-ray signal readout systems can be used in connection with the electron probe analyzer, new readout techniques can be applied with advantage, particularly for scanning procedures. Several novel techniques involving photographic recordings of oscilloscope tracings will be described. These techniques are applicable to area scanning (enhanced concentration method, concentration mapping with use of X-ray signals, and target current concentration mapping procedures) as well as line scanning. Combinations of area-scanning images with line-scan registration ate used for representing line-scan results.By using operational amplifiers as signal adders, wavelength scans can be efficiently registered on a Polaroid photogram, with baseline indication and wavelength markers, in a single exposure. Another wavelength scanning technique registers the pulse height of the lines observed during the scanning operation, so that the order of reflection of the lines can be established. The use of an x-y recorder also offers advantages in the registration of line scans. Techniques for registration of multiple scans and for concentration mapping with the x-y recorder will be described.
Detection Confirmation and Determination of Trace Amounts of Selenium by X-Ray Methods
Authors: Chan Frank L. 
Published: March 2019

AbstractRecently, interest in the determination of selenium in trace amounts has been greatly intensified because of the nutritional aspects of this element. It has been reported that selenium in the amount of 13 μg in the form of sodium selenite in 100 g of feed has an effect similar to that of vitamin E. In the field of semiconductors, the detection and determination of trace amounts of selenium in arsenic, antimony, and small single crystals of solid solution of cadmium selenide and sulfide are of considerable importance in semiconductor performance.In the Aerospace Research Laboratories, 4,5 diamino-6-tbiopyi-imidine has been successfully adopted as a reagent for the spectrophotometric determination of selenium. The reaction of 4,5 diamino-6-thiopyrimidine and tetxavalent selenium produces a yellow color with the formation of elemental selenium. It is possible to determine elemental selenium by collecting it in a thin layer. The selenium deposited in this layer may then be determined by an X-ray fluorescence method. A procedure of this nature has the advantage of eliminating the matrix effects commonly encountered in X-ray fluorescence. Furthermore, the slow generation of selenium affords a convenient means of detection and confirmation of this element by the use of X-ray diffraction procedures. By this technique selenium is first converted to its tetravalent state and is then reacted with 4,5 diamino-6-thiopyrimidine. On standing, the selenium is reduced to a red precipitate of elemental selenium which can be dissolved in carbon disulfide. Finally, the selenium can be converted into its hexagonal structure by annealing at 205-207°C.
X-Ray Spectrometric Determination of Composition and Distribution of Sublimates in Receiving-Type Electron Tubes*
Authors: Bertin Eugene P. , Longobucco Rita J. 
Published: March 2019

AbstractDuring the normal operation of conventional receiving-type electron tubes, certain metallic elements, such as barium, strontium, nickel, and manganese, sublime from the hot cathode and deposit on cooler parts of the tube. This process gradually impairs the performance of the tube and may eventually limit its useful life. This paper describes some applications of a variety of X-ray spectrometric techniques to the qualitative and quantitative analysis of these sublimates and to the mapping of their distribution on various surfaces in the tubes.All work was done on a standard commercial X-ray spectrometer, but specially designed accessories are described for mounting and rotating small parts in the primary X-ray beam and for confining the beam to these parts. Procedures are given for analysis of microgram deposits on electron-tube cathodes, grids, plates, micas, and bulbs by both nondestructive and filter-paper-disk techniques. Procedures are given for point-by-point mapping of the distribution of sublimates over the surfaces of these parts by use of a commercial “X-ray probe” selectedarea accessory in conjunction with a curved crystal to give increased intensity. Procedures are given for various techniques for calibrating all the analytical methods, including preparation of thin films of known composition.The results of some typical electron tube studies are described and illustrated. The approximate sensitivity of the methods for determination of total sublimate is, in micrograms per part, 0.1 for barium, strontium, and manganese and 0.05 for nickel. The approximate sensitivity for mapping sublimate distribution with a 1-mm aperture is, in micrograms per square centimeter, 1 for barium, strontium, and manganese and 0.5 for nickel. Although the techniques described are applied specifically to sublimates in electron tubes, they are also readily applicable to analysis of specks and films on other small parts and to thin-film studies in general