bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Evaluation and Improvement of X-Ray Emission Analysis of Raw-Mix and Finished Cements
Authors: Andermann George , Allen J. D. 
Published: March 2019

AbstractWith modern X-ray instruments, precision is generally satisfactory for the analysis of MgO, Al2O3, SiO2, CaO, and Fe2O3 in finished and raw-mix cements and other similar materials. Accuracy, that is, agreement between cheraicaland X-ray values, quite frequently is much worse than precision. Some typical examples illustrating this point are reviewed.In the soft region, generally, it has not been possible to assign the cause of iuaccuracy to interelement effects. The hypothesis is formulated that in the soft region this problem could be due to mineralogical differences and inhomogeneity on a micro scale. Theoretical calculations support the plausibility of this argument.To improve accuracy, present techniques have been based on type standardization, acid digestion fusion using a high flux-to-sample ratio, etc. In general, these methods have certain basic limitations. In order to retain useful intensities and lineto- background ratios for the soft region, 8 new fusion technique has been developed. The experimental data based on this method of reducing micro-inhomogeneity and eliminating minaralogical differences indicate improvements in accuracy. In the case of finished cements the improvements in accuracy have been quite modest. With rawmix cements, startling improvements have been obtained for the analysis of SiO2 and CaO.
New Instruments for X-Ray Analysis
Authors: Furnas Thomas C. , White Eugene W. 
Published: March 2019

AbstractNew Instruments for X-ray or neutron diffraction or for analyses by X-ray spectrographic methods are described. They incorporate a variety of new features which open a broad new scope of experimental techniques to the investigator. The diffractometer can be used with the diffraction plane either horizontal or vertical. The X-ray tube is conveniently supported by the diffractometer, allowing one to adjust the take-off angle from 0 to 10° without disturbing the precise alignment of the instrument. The 2θ angle bisecting mechanism functions throughout a 360° range and allows independent rotation (ω) of the specimen about the common axis. It is designed specifically for fully automatic remotely programed operation in addition to the usual manual modes.The constant-potential generator is rated up to 50 ma at 50 kvcp and up to 40 ma at 60 kvcp, A monitor-type switch selects combinations of kilovolts and milliamperes in a manner such that exact reproducibility of settings is assured.The dual-function strip-chart recorder incorporates both linear and three-cycle logarithmic slide wires so that each uses the output from the same linear rate meter.The Integrated Radiation Analyzer consists of a pulse-height analyzer, electronic timer, high-speed sealer, precision linear ratemeter, power supply, printer, and diffractometer control. Integration of these components has made possible unique programing for X-ray analysis.
Novel Features Incorporated in a New Automatic X-Ray Fluorescence Spectrometer
Authors: Whitcomb Peter B. 
Published: March 2019

AbstractA flat-crystal spectrometer is described that is fully evacuated to permit analysis of light elements. A uniselector in conjunction with a programing unit allows the crystal to be moved to any series of angles with stopping intervals as close as 0.01°. Detectors are a scintillation counter and a flow proportional counter driven at twice the angular velocity of the crystal to maintain them in correct position, A further detector is used to monitor the primary X-ray beam. Programing is achieved by means of a patchboard, and each board allows up to 20 elements to be measured at one time and in a sequence as desired, Pinal results appear in tabular forrn on an electric typewriter. Provisions are also provided for continuous scanning, the X-ray spectrum being plotted on a strip chart recorder. The sample is brought into position with a slide arranged so that the spectrometer may be kept continually evacuated and only a small pocket of air need be pumped. Alternately, helium may be used with resultant low consumption per sample.
X-Ray Investigations on Some Salts of Hydrazine and Hydrazine Derivatives
Authors: Stammler M. , Orcutt D. 
Published: March 2019

AbstractThe salts of hydrazine or methyl derivatives of hydrazine were prepared by neutralization of the base with inorganic acids, for instance, HBF4, HClO4, H SO4, and HCl. Upon recrystallization of the product from a suitable solvent, X-ray diffraction patterns were obtained. Hydrazine tetrafluoborate H2N-NH2·HBF4 was found to crystallize in the monoclinic system. Cell dimensions and possible space groups were determined. The corresponding perchlorate salt crystallizes in two forms, one of which is isomorphous with hydrazine tetrafluoborate. The second form seems to be stabilized by small amounts of water.The tetrafluoborate salt was prepared from the 1,1-dimethyl hydrazine. It was found to crystallize in the tetragonal system with a primitive unit cell. The perchlorate salt of this base is isomorphous with the fluoborate but with a slightly larger unit cell. Both materials undergo plastic-like deformation. The general appearance and mechanical properties are similar to those of a hydrocarbon wax. The 1,1-dimethyl hydrazine sulfate and the 1,1-dimethyl hydrazine hydrochloride have a lower symmetry than the HBF4 salt and do not show the wax-like properties of the latter. Based on the study of these chemically related compounds an explanation is offered for the properties of 1,1-dimethyl hydrazine tetrafluoborate in terms of crystalline structure.
A High-Temperature X-Ray Diffractometer Specimen Holder
Authors: Dreikorn R. E. 
Published: March 2019

AbstractA high-temperature X-ray diffractometer specimen holder that fits on a standard General Electric diffractometer is described. The thermal expansion of iridium from 23 to 1720°C is reported as 7.5 • 10−6−6 per °C and diagrams made at 2000°C are shown.
A Weighted Least-Squares Parametric Method of Reducing Nuclear-Reactor Gamma Spectral Data
Authors: Whiton J. C. , Gamble R. L. , Thornton R. M. 
Published: March 2019

AbstractA mathematical method has been developed which reduces nuclear-reactor gamma pulse-height spectral data to the form of differential energy spectra through the use of a high-speed computer machine. In essence, the method consists of a least-squares fit of weighted multichannel analyzer data and the utilization of curve-smoothing parametrization. The least-squares approach tends to reduce the magnitude of data that must be handled, i.e., reduces the order of matrix involved. Weighting is used to obtain fractional deviations for minimization by lease squares and thus obtain a satisfactory fit throughout the entire channel range. The parametrization smoothes the reduced data by making use of the fact that reactor gamma spectra can be represented by the product of an exponential and a polynomial. Difficulties that arise when pure matrix inversion is applied have been obviated, and the advantage of high-speed data reduction is gained through the use of an IBM 704-7090 computer program. Error analyses have been undertaken, and data have been reduced for comparative purposes. Results are included in the presentation of the investigation.
X-Ray Absorption-Edge Determination of Cobalt in Complex Mixtures*
Authors: Hakkila E.A. , Waterbury G.R. 
Published: March 2019

AbstractThe application of the X-ray absorption-edge technique was extended to the determination of cobalt in aqueous and alcoholic solutions containing a wide variety of impurity elements. In the procedure developed, secondary radiation from a 50% copper-nickel alloy is passed through an absorption cell filled alternately with the solvent and the sample solution. The transmitted Intensities of the Kα lines for copper and nickel are measured, and the concentration of cobalt is determined using accepted absorption principles. The K absorption edge for cobalt occurs at 1.604 A, restricting cell construction materials and solvents to those containing light elements with low X-ray absorption characteristics and also limiting the path length of the cell.Cells of 0.16- and 0.34-cm path length were used in the analysis of aqueous and alcoholic solutions, respectively. With the 0.16-cm path-length cell, relative standard deviations of 4.6 to 0.5% were obtained for cobalt concentrations ranging from 1.00 to 10.00 mg/ml for known aqueous solutions that contain various known concentrations of nitric acid. With the longer path-length cell, relative standard deviations from 1.8 to 0.46% were obtained for cobalt concentrations in the same range in known alcoholic solutions containing various known concentrations of nitric acid. The standard deviation of determining the blank is 0.043 mg of cobalt per milliliter for the 0.16-cm cell and 0.016 mg of cobalt per milliliter for the longer cell.A Norelco X-ray spectrograph with a three-position head was used in these analyses. Less than 5 min is required to convert this instrument from normal fluorescence operation to absorption-edge analysis. Approximately 15 to 20 analyses can be performed daily.
Surface Preparation of Solid Metallic Samples for X-Ray Spectrochemical Analysis
Authors: Michaelis R.E. , Kilday Betty Ann 
Published: March 2019

AbstractIn X-ray spectrochemical determinations, the surface preparation of metal samples is important since the emitted secondary radiation is absorbed except for that emerging from the immediate surface. Surface preparation also has been found to be a critical factor in eliminating or at least in minimizing the effects of certain metallurgical changes among or within samples on the X-ray determinations. For example, a change of particle size of an undissolved constituent, or a change in grain size, may markedly influence the X-ray analysis, depending on the surface preparation. A metallographic polishing technique, whereby the sample surfaces were finished with ¼μ diamond dust, was reported for the determination of lead in leaded steel (Kilday and Michaelis, in press). This investigation has been extended to other materials such as hypereutectic silicon-aluminum alloy and white-cast iron. A comparison is made of the effects of different surface preparations on X-ray determinations.
Diffraction Effects from Irradiated Aluminum Single Crystals*
Authors: Kissinger H. E. 
Published: March 2019

AbstractThe effect of substructural perfection on the accumulation of irradiation damage in aluminum was examined. Large single crystals with extensive substructure and crystals essentially free of substructure, all with faces cut parallel to crystal planes, were subjected to neutron irradiation. Subsequent examination by X-ray diffraction revealed pronounced changes in integrated intensity and Debye-Waller temperature factor for the substructure-free crystals; these effects disappeared upon re-etching of the surface. Laue photographs showed that the normal single-crystal pattern was partially obscured by a polycrystalline effect which also disappeared upon etching. Crystals with extensive substructure showed no such effects.This diffraction evidence supports the view that irradiation-induced defects in aluminum migrate to and collect at the crystal surface if no internal trapping sites exist.
Low-Temperature Transitions of Some Ammonium Salts
Authors: Stammler M. , Orcutt D. , Colodny P. C. 
Published: March 2019

AbstractX-ray diffraction studies were performed on ammonium fluoroborate [NH4BF4], ammonium perchlorate [NH4ClO4], ammonium chloride [NH4CI] and ammonium phosphate [(NH4)H2PO4] within a temperature range of ambient to −190°C. For these experiments a specimen holder was designed to effect rapid cooling of the sample. Results indicate that the fluorob orate and perchlorate salts undergo a polymorphic transition at −190°C. The decreasing intensities of the (011) and (112) reflections of the orthorhombic modification indicates a firstorder reaction. No transition was observed when these salts were cooled to −40°C. The ammonium chloride shows a transition at about −30°C which confirms the results obtained by G. H. Goldschmidt and D. G. Hurst. The ammonium phosphate (NH4)H2PO4, which is tetragonal at ambient temperature also undergoes a transition if cooled to −190°C. The kinetics of this reaction are discussed.
Some X-Ray Generator Characteristics to Consider in Order to Realize the Optimum Stability and Reproducibility of Intensity Measurements
Authors: Torkildsen R. 
Published: March 2019

AbstractThis paper presents some of the physical considerations which must be considered in operating an X-ray generator to obtain maximum stability and reproducibility of intensity measurements. In addition, a typical X-ray generator will be discussed from the standpoint of enabling the user to realize all of the stability and reproducibility capabilities which were designed into the equipment.
Determination of Aluminum in Iron-Aluminum Alloys by Vacuum X-Ray Fluorescence
Authors: Wagner J. C. , Bryan F. R. 
Published: March 2019

AbstractAluminum, is determined within the range 2-16% in iron. Repeatability of X-ray determinations is within a standard deviation of 0.07 % aluminum for a sample containing 10.2% aluminum. The standard deviation of the chemical values from the straight line calibration curve is 0.3% aluminum. X-ray analytical time is approximately 5% of the time required for chemical analysis. Peak-to-background ratio is improved by using a chromium-target thin-window X-ray tube instead of a tungsten tube.
Design Considerations for On-Stream X-Ray Analysis
Authors: Kiley W. R. , Deichert R. W. 
Published: March 2019

AbstractSeveral design concepts were evaluated for on-stream X-ray analysis, chief among which were: (1) sample presentation, (2) X-ray spectrograph and (3) data handling. The sample is presented to the X-ray spectrograph through a vertical cell having a mylar window and a device to measure variations in sample density. The X-ray spectrograph is of fixed-channel, modular design, with a capacity of up to six channels, and is designed for use in industrial environments. The complete spectrograph can be translated in a horizontal plane to position itself and determine the elemental composition in a series of sample cells. The data handling uses digital circuitry to permit normal use of analog readouts or digital data logging systems. Operational data are given for on-stream analysis.
The X-Ray Diffraction Measurement of Residual Stresses in Aluminum Alloys
Authors: Larson Ronald C. 
Published: March 2019

AbstractThis paper presents the theoretical and practical aspects of measuring residual stresses by X-ray diffraction with emphasis on the analysis of aluminum alloys. The theoretical considerations of radiation) beam geometry, and peak location will be discussed in regard to establishing optimum analysis techniques. The precision and reproducibility of this technique have been investigated so that results can be applied accurately. The approach, however, is basically a practical one, with the intent of studying residual stress systems as they affect engineering applications. Residual stress systems produced by thermal and mechanical treatments have been determined and the effect of treatment modifications and variations on the resultant stress system have been analyzed. The effect of operational variables such as time and temperature on the developed stress system are shown. From this, the merits of a particular treatment can be determined with respect to its intended application.Analysis of solution heat-treated and quenched 2014 aluminum has shown a significant effect of the quench temperature on the resultant residual stress system. The results obtained from shot-peening this alloy are presented, as well as the effect of time and temperature on the shot-peened stress gradient.
Analysis of the Broadening of Powder Pattern Peaks from Cold-Worked Face-Centered and Body-Centered Cubic Metals
Authors: Wagner C. N. J. , Aqua E. N. 
Published: March 2019

AbstractThe broadening of powder pattern peaks of metals is normally caused by small crystallite size and by distortions within the crystallites as a consequence of dislocation configurations. In addition, the experimental diffraction geometry contributes to the line broadening. Using Cu Kα radiation, we recorded the peak profiles of the cold-worked and annealed filings of tungsten, niobium, aluminum, and silver-indium alloys with a standard focusing diffractometer. The Rachinger method was applied to separate the Kα1 and Kα2 peaks, and the Kα1 peaks were subjected to a Fourier analysis. Elimination of the instrumental broadening was carried out by the Stokes method, which does not require any assumptions concerning the mathematical description of the diffraction peak profile.The Fourier coefficients, AL, were separated into the fraction produced by particle size, ALFF, and by strains, ALe, by the Warren-Averbach method and plotted as a function of the distance L = ndhkl, normal to the reflecting planes (hkl) of spacing dhkl. The negative, reciprocal initial slope of the ALPF vs. L curve is equal to the effective particle size Deff, which contains the effects of the true crystallite size and faulting. The coefficients ALβ = AL/ALPF are used to calculate the root mean square strain <∊L2>1/2. The sum of the ALPF, which is proportional to a reciprocal integral breadth, leads to a different particle size, DWAPF, which is also dependent upon the crystallite size and faulting. The sum of the AL6 values is a measure of the strain ƐWA.The integral breadths bst, corrected by the Stokes method, i.e.,are separated into a particle size term bstPF and distortion term bSts using the relations . It is found that only the first relation leads to particle sizes DG,StPF and strains ∊G,st similar to those obtained by the summation of the ALPF and AL6, i.e., DWAPF and ∊wA, respectively. The integral breadths of the cold-worked peaks Bew and of the annealed standards bA. were also calculated, using the Lauc definition of B equal to area per peak maximum. A comparison of the values of bst/Bcw with bA/Bew for bA/Bew < 0.6 shows that all data follow the parabolic relation b/Bew = 1 − bA2/Bew2. The maximum deviation of bst/Bew from the parabola is less than 10%.
Dependence of Lattice Parameters on Various Angular Measures of Diffractometer Line Profiles*
Authors: Parrish W. , Taylor J. , Mack M. 
Published: March 2019

AbstractWhen the accuracy of a lattice parameter determination is carried beyond about 0.01 % it becomes of special importance to consider the equivalence of λ and θ in solving the Bragg equation for d. A reference angle on the observed diffractometer profile must be identified with the corresponding wavelength, of the incident X-ray spectral distribution. Exact identity is not possible because the diffractometer profiles are broadened, distorted asymmetrically, and displaced from their correct positions by amounts dependent on the shape of the incident spectral lines, the angular separation of the Kα1,2 doublet lines, and the specimen, instrumental, and geometrical aberrations innerent in the experimental method. The aberration functions vary with the experimental conditions and are Bragg-angle-dependent, thereby introducing systematic errors which are not eliminated by extrapolation procedures.Most of the published diffractometer measurements of lattice parameters have used as the reflection angle, 28, of the diffractometer profile the peak P(2θ) or the midpoint of chords at various heights above background M1/2(2θ), M2/3(2θ), etc., of the Kα1 line. The relationship between these various angular measures of the line profile is not constant; P(2θ) may be equai to, greater than, or less than M1/2(2θ), depending on the asymmetry of the line profile. The X-ray wavelengths currently used in diffractometry refer to the peak P(λ) of the spectral distribution. The use of P(λ) with different angular measures of the diffractometer profiles results in a range of d's from which different values of the lattice parameters are calculated. The selection of arbitrary methods of defining 2θ does not take into account the significant aspects of the diffraction process, nor does it facilitate the correction of the data for systematic errors inherent in the experimental measurements.
Prealloyed Iron-Nickel Powders by an Amalgamation Process
Authors: Peavler R. J. , Ananthanarayanan N. I. 
Published: March 2019

AbstractX-ray studies indicate that mixed iron and nickel “amalgams” are reactive even at room temperature. By distilling off the mercury from these amalgams at temperatures between 400 and 100°C, ultrafine iron-nickel alloy powders are readily obtained. X-ray studies show that these powders possess equilibrium structures corresponding to the temperature of preparation. Alloy powders belonging to many alloy systems and having controlled composition, purity, and particle size may be prepared by this process. One special use of the process is in the preparation of homogeneous alloy powders for studying solid state equilibria below 400°C, particularly in alloy systems with sluggish transformations, the process being invaluable in the temperature range between 200 and 100°C, Another is in the preparation of ultrafine metal and alloy powders with equally fine, if not finer, dispersions of other phases, suited for studying dispersion-strengthening. Both of these special uses are currently under investigation,
A Study of Solid-Solution Formation in the Milling of TiCl3—AlCl3 Powder Mixtures
Authors: Wilchinsky Zigmond W. , Looney Ralph W. 
Published: March 2019

AbstractSolid solutions of AlCl3 and TiCl3 were formed in all proportions by milling together dry powders of AlCl3 and TiCl3 (delta crystalline modification). For each composition, X-ray diffraction showed a single phase having a high degree of layer stacking disorder. These materials, including milled AlCl3, were isomorphous with the so-called delta modification of TiCl3.The presence of solid solutions was investigated primarily by lattice parameter measurements made with a diffractometer and carried out with the aid of internal standards. For the milled materials, lattice parameter changes were observed not only with changes of composition, but also with the crystallite size. In terms of the system of hexagonal axes used for α TiCl3, the a parameter for the milled samples decreased with decreasing crystallite size, whereas the c parameter increased. In the samples examined, this effect was about the same order of magnitude as that due to changes in composition. In order to evaluate the effects due to composition alone, a correction was made for the effect of crystallite size, and the lattice parameters were then expressed as the limiting values one would obtain for very large crystals.With increasing AlCl3 content, the a parameter decreased from 6.168 Å for no AlCl3 to 6.162 Å for 20 mol.% AlCl3. For higher AlCl3 content, a showed a relatively rapid and almost linear decrease to 5.921 Å for 100% Aids. The c parameter decreased from 17.73 Å for no AlCl3 to about 17.61 Å for 35 mol.% AlCl3, and thereafter decreased slowly to 17.58 Å for 100% AlCl3. The layer stacking disorder appeared to increase the lattice parameters in solid solutions containing less than 25 mol,% AlCl3. However, at 25% and 100% AlCl3, no significant effect was observed.