bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Miniature Instrument for Residual Stress Measurement
Authors: Ruud C. O. , DiMascio P. S. , Snoha D. J. 
Published: March 2019

AbstractThe Pennsylvania State University has developed and tested a miniature x-ray instrument for the measurement of residual stress (strains). The stress head including x-ray source and detection surface is approximately four and one-half inches long and can be inserted into an orifice less than two and one-half inches in diameter. This head is on the end of a several-foot long cable and is extremely manipulatable.The instrumentation design is based upon a unique position sensitive scintillation detector which ie capable of applying the single-exposure x-ray stress measurement technique. Total lapse time data collection periods for aluminum alloys are less than ten seconds with x-ray tube powers of 120 watts. Results from a four-point bend test on an aluminum alloy specimen showed excellent precision. The configuration of the instrument and the procedures for its application are described.
Quantitative Analysis: A Comparative Study Using Mo and Cu Radiation on Coal Related Minerals and Fly Ash
Authors: Amenson J. , Benson J. , Demirel T. , Jacobson R. 
Published: March 2019

AbstractOur experience using Mo Kα radiation in coal related research indicates that minerals can be detected and quantitatively measured at the 0.2% level in an amorphous substance such as coal. Since the linear absorption coefficient for most elements is about a factor of eight lower for Mo radiation than it is for Cu radiation, the matrix affect is greatly reduced and the intensity is a more linear function of concentration.Although there is considerable overlapping of peaks when complex mixtures are analyzed using Mo radiation, the use of second derivative techniques to locate peaks, and least squares techniques to fit peaks can resolve many of these problems. The reduced time needed to collect a diffraction pattern, and the increased intensity obtained more than compensate for the extra computer time needed to analyze the data.
Quantitative X-Ray Fluorescence Analysis for Fly Ash Samples
Authors: Schlorholtz Scott , Boybay Mustafa 
Published: March 2019

The disposal of fly ash from coal burning power plants is rapidly becoming an environmentally complex problem. Recently though, the attitude towards fly ash use has been changing from a disposal oriented point of view to a more rational position which considers fly ash as a resource to be recycled. One major hinderance of fly ash use has been the extreme variability of composition that exists between fly ashes produced at different power plants. This variability makes the analysis of fly ash very important.The most common methods currently used for fly ash analysis are atomic absorption or wet chemistry methods defined in ASTM C311. Both methods tend to be expensive, time consuming, and sample preparation is both tedious and critical for some elements. In this study X-ray fluorescence (QXRF) is used for the quantitative analysis of the major and minor elements found in “typical” fly ashes. The method, which is computer controlled, is quick, reliable, and requires minimal sample preparation.
A Mathematical Comparison of the Lachance - Traill Matrix Correction Procedure with Statistical Multiple Linear Regression Analysis in XRF Applications
Authors: Klimasara Anthony J. 
Published: March 2019

AbstractIt will be shown that the Lachance-Traill XRF matrix correction equations can be derived from the statistical multiple linear regression model. By selecting and properly transforming the independent variables and then applying the statistical multiple linear regression model, the following form of the matrix correction equation is obtained:Furthermore, it will be shown that the Lachance-Traill influence coefficients have a deeper mathematical meaning. They can be related to the multiple regression coefficients of the transformed system:Finally, it will be proposed that the Lachance-Traill model is equivalent to the statistical multiple linear regression model with the transformed independent variables. Knowing these facts will simplify correction subroutines in Quantitative/Empirical XRF Analysis programs. These mathematical facts have already been implemented and presented in a paper: “Automated Quantitative XRF Analysis Software in Quality Control Applications” (Pacific-International Congress on X-ray Analytical Methods, Hawaii, 1991).This demonstrates that the Lachance-Traill model has a strong mathematical foundation and is naturally justified mathematically.
SUPERXAP- A Personal-Computer-Based Program for Energy-Dispersive X-Ray Spectra Analysis
Authors: Yager D.B. , Quick J.E. 
Published: March 2019

AbstractSUPERXAP (Super X-ray Analysis Program) enables IBM-compatible personal computers to analyze energy-dispersive spectra using least-squares spectral deconvolution. The program corrects for instrument drift, background, peak overlap, and matrix effects. Pull down menus provide 24 subroutines and functions, that allow spectra to be transferred, stored, viewed, manipulated, and analyzed. Spectral peaks can be identified manually or automatically with color-coded K, L or M lines. Working curves are developed using an interactive routine that creates standard files by least-squares fitting of peak intensities to known elemental abundances. Elemental abundances in unknowns may be determined in a variety of ways including on-line analysis of spectra as they are generated by an energy-dispersive detector and by batch analyses of spectra stored on disk. Standard deviation, based on counting statistics, is reported for each element in each analysis. Written in QuickBASIC 4.5 for interface with a KEVEX 7000 radioactive-source x-ray fluorescence analyzer, SUPERXAP could be adapted, with minor modification, to accept and analyze data from other instruments that produce energy-dispersive spectra.
X-Ray Diffraction from Multilayers with Different Microstructures
Authors: He Ping , Woolkm John A. , Sequeda Federico O. 
Published: March 2019

AbstractX-ray diffraction measurements were performed on CoαPt1-α/Pd, Co/Pd, Co/Fe, and Co/W multilayer samples with different structures, such as CoαPt1-α alloy layer composition α, bilayer thickness, and number of bilayers. Multilayer samples were made by magnetron sputtering in a chamber with multi-parallel guns and a position controllable substrate. CoαPt1-α alloy layers were deposited by cosputtering from Co and Pt targets mounted on guns tilted towards a common substrate. Compositions of Co and Pt in CoαPt1-α layers were varied by use of different sputtering power. The thicknesses of magnetic and non-magnetic layers in multilayered samples were also systematically changed to investigate the relationship between x-ray diffraction lines and crystalline structures of multilayered films. It was found that the position of the main diffraction peak from multilayered films was solely determined by the crystalline structures within bilayers rather than bilayer thickness. A model was introduced to calculate microstructural parameters such as the thickness of interfaces and compositions at interfaces.
Residual Stress Measurements on Cr/Ni Pads Evaporated on Polyimide Thin Films
Authors: Goldsmith C. C. , Van Buskirk C. 
Published: March 2019

AbstractPolyimide films are becoming more important in multi-layer structures, acting as dielectric films to separate conductive layers. High thin film residual stresses can cause problems with the polyimide film, leading to loss of adhesion between the metal film and the polyimide or can cause cracking in the polyimide.In this paper, we examine the residual stresses in “as deposited” metal films evaporated onto BTDA-APB polyimide films and follow the change in residual stress of the nickel layer during subsequent thermal processing. We will show that the change in residual stresses can be correlated to the glass transition temperature of the polyimide film.
Thin Film Critical Residual Stress for Metal Pads on a Ceramic Substrate
Authors: Goldsmith C. C. , Kamath S. M. , Kumar A. H. 
Published: March 2019

AbstractResidual stresses present in thin films evaporated on ceramic substrates, can lead to loss of adhesion of the metal features to the ceramic, or, between metal films in multi-level stacks. If the adhesion is good, ceramic cracking may occur around the metal features. Long term one must avoid stress corrosion cracking in the ceramic. These residual stresses are generated by a variety of causes. In general, defect incorporation during the deposition process and thermal expansion mismatch between thin film and substrate play major roles.In this paper, we describe a method for determining the residual stresses that may be detrimental, or more accurately, the residual stress induced load that may cause reliability problems. This method involves evaporating metal pads or various thicknesses onto the ceramic to the point of failure, and measuring the residual stress loading on the substrate. A direct measure of this loading is the stress intensity factor which takes into account both the residual stress and pad or film thickness. Thus, a critical “load” or stress intensity at which substrate cracking or thin film delamination occurs can be estimated. This approach can be used to select the optimum metal-thickness combination for various substrates.
X-Ray DCD and EPMA Measurements of Al Concentration in Epitaxial AlxGa1-xAs/GaAs Layers
Authors: Macquistan D.A. , Bassignana I.C. , SpringThorpe A.J. , Packwood R. , Moore V. 
Published: March 2019

AbstractDouble Crystal X-Ray Diffraction (DCD) is often used to determine the Al content of AlxGa1-xAs/GaAs epitaxial layers. Assessing composition from a measurement of mismatch is problematic because it invokes a number of assumptions. This study bypasses these difficulties by comparing the measurement of mismatch directly with Al composition measurements made by electronprobe microanalysis. A study of coherent epitaxial AlxGa1-xAs layers showed that mismatch varies linearly with composition. The equation Al (x) = |ΔΘ| / 368 summarizes the relationship over the coherent range, where |ΔΘ| is measured in arc seconds.
Near-Surface-Layer Analysis by Critical Takeoff-Angle X-Ray Fluorescence Detection
Authors: Hayakawa Shinjiro , Sasaki Satoshi , Gohshi Yohichi 
Published: March 2019

AbstractNear-surface-layer analysis by x-ray fluorescence critical takeoff-angle detection was examined theoretically and experimentally. The takeoff-angle dependence of Cr K-L x-ray fluorescence from Cr thin films was measured with practical analyzed depth varying from several thousand to less than one hundred angstroms. Comparison of Cr K-L and K-M takeoff-angle dependence shows the analyzed depth depends on the observed x-ray energy even with identical takeoff angles. The potential of nondestructive depth profiling is also discussed.
Phase Identification using Whole-Pattern Matching
Authors: Smith D. K. , Hoyle S. Q. , Johnson G. G. 
Published: March 2019

AbstractThe use of whole-pattern matching techniques for phase identification provides increased confidence in the phases determined compared with d-I matching and enhances the potential for determining the existence of phases present in low concentrations. Reference patterns from a database of selected phases were compared with the experimental pattern obtained from an unknown, and the results were ranked using figures-of-merit designed to distinguish the best pattern matches. Several different figures-of-merit have been evaluated, all of which proved successful in recognizing the strongest phase but varied with respect to the other phases.Low-concentration phases are revealed when the patterns of the more abundant phases are stripped from the experimental trace using the best-fit scaled reference traces. Pattern stripping is improved by pattern shifting and profile shape matching which are provided for in the matching program.
An Algorithm for Correction of Intensity Aberrations in Bragg-Brentano X-Ray Diffractometer Data; Its Importance in the Multiphase Full-Profile Rietveld Quantitation of a Montmorillonite Clay
Authors: Matulis C.E. , Taylor J.C. 
Published: March 2019

AbstractIntensity aberrations in Bragg-Brentano X-ray diffractometers reduce the measured intensities at low angles relative to higher angles, and the correction factor can be large at low 2θ angles. Aberration-free data is of great importance in full-profile Rietveld quantitative analysis or structure refinement. An algorithm is given which corrects the intensity aberrations for particular instrument dimensions and sample absorbance, with a fixed divergence slit. Variable divergence slits increase the Bragg-Brentano aberrations and skew the data. The importance of an aberration correction curve produced with the computer program BBCCURV is described in the multiphase Rietveld quantitation of a montmorillonite clay with the SIROQUANT quantitative analysis program system; good quantitation of the montmorillonite can only be obtained if the aberration corrections are applied.
Phase Analysis of Portland Cement by Full Profile Standardless Quantitative X-Ray Diffraction - Accuracy and Precision
Authors: Taylor J.C. , Aldridge L.P. 
Published: March 2019

AbstractThe multiphase Rietveld method has been used in the determination of phase abundance in six standard Portland cements, using the SIROQUANT personal computer software package for XRD quantitative analysis. Because of the extreme amount of line superposition and weakness of the cement patterns care must be taken in the selection of standard XRD profiles and in the refinement of unit cell dimensions and linewidths. Comparison with round-robin microscope assays of the same cements shows r.m.s. deviations of assays between the two methods of 2.1% for alite, 3.1% for belite, 1.7% for aluminate and 1.3% for ferrite. Precision, studied by repeated SIROQUANT analyses of nine XRD patterns from the same Australian cement show esd's of 1.3% for the alite assay, 0.8% for belite, 0.5% for aluminate and 0.5% for ferrite.
XRD Pattern Fitting as a Tool to Control Plating Parameters in Zinc Nickel Electroplates
Authors: Hammond Lloyd , Wright Don 
Published: March 2019

AbstractRietveld X-ray powder diffraction (XRD) and uniaxial stress measurement procedures are being evaluated as a means of correlating the crystalline structure properties of zinc-nickel electroplate with observed plating properties. The study is being performed on a suite of six samples of varying composition (6 to 20%Ni) electrodeposited on mild steel. Rietveld refinement of the XRD data (Rietveld, 1969) has been performed on a specially prepared ingot (9%Ni:91%Zn) to determine the structural parameters and relative abundances for the γ(Ni4Zn22), δ(Ni3Zn22) and η(Zn) phases which could possibly be present in the electroplate. Relative phase abundances were verified by Atomic Absorption Spectrometry (AAS) and electron probe microanalysis (EPMA) image mapping techniques.The structural parameters for the ingot zinc-nickel phases were subsequently used as initial parameters in Rietveld calculations for the six electroplate samples. Structure refinement of the electroplate XRD data was hampered by extremely high preferred orientation and the corresponding lack of quality diffraction peaks. However, Rietveld refinements produced accurate cell dimensions (which correlate linearly with nickel composition), a means of quantifying the degree of preferred orientation, and crystalline phase verification. For residual stress determination, d-sin2ψ plots were produced for each electroplate sample. The plots were found to be linear for Ni < 12%, allowing calculation of residual stress, and distinctly curved for Ni > 12%.
An Advanced Technique for High Temperature X-Ray Elastic Constant and Stress Investigations
Authors: Liu Chun , Lebrun Jean-Lou , Sibieude François 
Published: March 2019

AbstractA high temperature in situ X-Tay diffraction (HTXRD) instrument was devised for residual stress (RS) and X-ray elastic constant (XECs) investigations. The aim was to gain a better understanding of the stresses developed during high temperature oxidation, which is essential for the lifetime improvement of refractory alloys. The investigators use sin2ψ method to survey the stress evolution during oxidation in both the scale and the substrate, and differential method to determine the XECs that relate the measured/measurable deformation to the stress state of the materials studied. The stresses on the Ni/NiO system are measured in situ. The XECs are determined on XC75 steel samples. This paper presents the theories of stresses and XECs determined by HTXRD and briefly discusses the experimental results.
Humidity Controlled Diffractometry and its Applications
Authors: Kühnel Radko A. , van der Gaast Sjerry J. 
Published: March 2019

AbstractHumidity sensitive mineral phases change their structure when humidity varies resulting in X-ray pattern changes in intensity, position, and shape of lines. These structural changes in hydrous minerals are induced by dehydration and rehydration, which can lead to phase transformations or to steady depletion which may result in a total structure collapse. By means of X-ray diffraction with a special attachment, such reactions can be followed. The controlled relative humidity is provided in situ, in a closed cell, by a flow of moistened helium gas which is flushed through the cell during the XRD analysis. Humidity diffractometry allows studies of reaction rates of dehydration-rehydration reactions and their reversibilities, as well as effects of additives and impurities on these reactions. Potential applications in basic research and in industry are demonstrated using montmorilionite, ettringites, sodium carbonates and calcium sulfates.
Measurement of Atomic Elastic Constants by Pulsed Neutron Powder Diffraction
Authors: Lawson A. C. , Kwei G. H. , Goldstone J. A. , Cort B. , Sheldon R. I. , Foltyn E. , Vaninetti J. , Eash D. T. , Martinez R. J. , Archuleta J. I. 
Published: March 2019

AbstractWe have developed a technique for determining the atomic elastic constants from measurements of the Debye-Waller factors. The Debye-Waller factors are obtained by Rietveld refinement of time-of-flight neutron diffraction data and interpreted in terms of an atomic Debye-Waller temperature. The method is applicable to powders and to materials that must be encapsulated for safety or environmental reasons. We will illustrate our technique with applications to actinide metals, to metallic hydrides and to high-temperature superconductors.
X-Ray Diffraction Study of Shock-Modified Tetragonal Phases of SnO2 and MnO2
Authors: Newcomer P. , Morosin B. , Graham R. A. 
Published: March 2019

AbstractX-ray diffraction line-profile analysis on tetragonal forms of SnO2 (cassiterite), MnO2 (pyrolusite), and previously studied TiO2 (rutile), which were subjected to high pressure shock loading, show that residual lattice strain and coherent “crystal” size are a function of shock parameters. An interesting observation on a sample of MnO2 concerns the recovery of cubic Mn2O3 (bixbyite) in the material subjected to 22 GPa, indicating a shock-induced chemical synthesis.
Peak Broadening in Asymmetric Powder Diffraction
Authors: Dragoi Danut 
Published: March 2019

AbstractIn the case of asymmetric X-Ray powder diffraction, usually used for stress analysis, the peak broadening is a function of the following instrumental parameters: divergence angle of incident and diffracted X-Ray beams (equatorial divergence), divergence angle of Soller slits (axial divergence), tilt angle ψ, and the intrinsic parameters of the sample (Bragg angle, size and mosaicity of the microcrystals, crystallographic imperfections due to atom impurities). This effect of peak broadening is discussed quantitatively, independent of the form of the peak, by using an approximation of a constant distribution of the intensities of diffracted X-Ray beams. The broadening effect due only to the ψ tilt of the sample surface is studied in this work. The results are compared with experimental data obtained on ceramic composite material: α-Al2O3/SiC(whisker).
An Experimental Examination of Error Functions for Bragg-Brentano Powder Diffractometry
Authors: King H.W. , Payzant E.A. 
Published: March 2019

AbstractA single function for the elimination of errors in precision lattice parameter determination has not been developed for the Bragg-Brentano x-ray diffractometer method, because of the different angular dependencies of the systematic errors. A review of the error functions shows that all but one can be calculated from the instrumental settings and known properties of a sample under investigation. The residual sample displacement error can be then be eliminated by using extrapolation plots or computer methods to correct the data to cosθcotθ plots. The slopes of cosθcotθ plots can also be used to align high temperature furnaces and low temperature cryostats mounted on x-ray diffractometers.
The Detection of Superlattice Lines in Cu-Zn Alloys using a Solid State Detector
Authors: Payzant E.A. , King H.W. 
Published: March 2019

AbstractUsing a high purity germanium solid state detector with sufficiently high energy resolution to discriminate between copper Kα and Kβ radiation, the superlattice reflections of the ordered Cu-Zn β′ brass structure have be detected by the anomalous dispersion effect. By coupling the high purity germanium solid state detector to a multichannel analyser, the superlattice reflections of the β′ brass structure were also detected by energy dispersive x-ray diffraction. Other applications for this combination of high resolution detector, electronic energy discriminator and multichannel analyser are indicated.
Effects of Refraction and Reflection on Analysis of Thin Films by the Grazing-Incidence X-ray Diffraction Method
Authors: Takayama Toru , Matsumoto Yoshiro 
Published: March 2019

AbstractThe grazing-incidence X-ray diffraction (GIXD) method was employed to analyze two-layer thin films, which were the samples of Å lOO Å Au/500Å Cu/Si02(substrate) and 250Å Cu/500Å Au/SiO2(substrate), which were prepared by the evaporation technique under the condition that the SiO2substrate was at room temperature. Diffraction profiles were obtained at various glancing angles ( α ) and the data were analyzed as a function of α. The results were as follows : 1) Diffraction peaks were shifted to larger diffraction angles, because of the refraction of the incident X-ray beam. The angular shift has been approximated by the equation, α - α2- αc2)1/2, where αcis the total ref reflection critical angle of the material. 2) As a result of the correction of angular shift, the stress of the evaporated films was estimated to be null. 3) The broadening of the Cu diffraction peak and the enhancement of the Cu diffraction intensity occurred at angles near αcof Cu, due to the reflection of the X-ray beam at the Cu/Au interface.
A Comparative Study of Stress Determination Techniques in Polycrystalline Thin Films
Authors: Noyan L. C. , Goldsmith C. C. 
Published: March 2019

AbstractA review of the literature has shown that two major techniques are used to determine stress/strain in thin film structures: curvature measurement technique and internal stress measurement by the traditional sin2ψ technique. However, to date, there is no published comparison of the results from both techniques when they are applied to a given specimen.In this paper we compare both methods theoretically and experimentally. We show that, while in some cases similar information is obtained from both techniques, there are cases where the two measurements give different results. We will show that, in such cases, the two methods can be complementary. Thus, they can be used to yield a more complete description of the total stress/strain tensor in the material.