bluuebunny/crossref_metadata_2025_split huggingface dataset:
A “Windowless” X-Ray Fluorescence Tube and a High-Resolution Diffractometer
Authors: Walker George 
Published: March 2019

AbstractA system is described whereby X-ray fluorescence analysis of elements below atomic number 19 (potassium) is undertaken with a “windowless” demountable X-ray tube. Comparison is made with 100-μ- and 30-μ-thick beryllium windows- Deflection plates are required before or behind the sample to eliminate scattered electrons. A high-resolution X-ray diffractometer is also described by making use of a fine focal line on the target. Burn-through due to localized heating on the target is eliminated by using a thermocouple arrangement.
The Application of Scanning Electron Microscopy and Energy Dispersive X-Ray Analysis to the Examination of Forensic Paint Samples
Authors: Wilson R. , Judd G. 
Published: March 2019

AbstractElectron optics techniques have been applied to the examination of various evidence materials common to forensic science. Vehicular paint fragments, a common evidence material, possess topographical features suitable for SEM analysis and composition variations in the form of chemically distinct layers and surface contaminant particles which can be characterized using energy dispersive X-ray analysis. The ability to analyze paint samples in terms of both topography and composition presents the potential of an extremely valuable tool for forensic investigators.Over thirty automotive paint samples from many sources were examined in this study, using either the secondary electron image of the SEM or the SEM image combined with concurrent X-ray analysis by an energy dispersive System. Topographical pictures and X-ray spectra were recorded and comparisons between samples were made. Additional characterization of specimens was attempted through the analysis of individual paint layers.The data obtained was used to group the paint samples into categories used for identification of the sample source. This information is valuable to several types of criminal investigation.
New Results Obtained with a Regular XRF Spectrometer and a Portable Field Spectrometer, Equipped with a Cold Cathode Electron Tube
Authors: Sahores J.J. , Larribau E.P. , Mihura J. 
Published: March 2019

The results presented here have been obtained with a regular Philips universal spectrometer, equipped with an irradiation tube radically different from those normally used. Since we have previously described this tube in past papers (1) (2) (3), we will therefore only briefly recall its principle.When starting this research program, our aim was to make possible the analysis of very light elements from sodium to boron, for a regular fluorescence spectrometer, without any modification of the spectrometer itself. As a matter of fact, the tube that we developed enabled us to reach this goal, but, moreover it opened some other possibilities :1) heavier elements could also be analysed2) thanks to the very low electric power required by this tube, a portable spectrometer could be built for field use3) since it allowed a very convenient study of low energy X-rays, we could easily measure energy levels of external electrons and thus study the influence of chemical or crystallographical structure on the X-ray spectrum.
Proportional Counter Parameters
Authors: Burek A. J. , Blake R. L. 
Published: March 2019

AbstractA flow proportional counter for ultrasoft x-ray applications has been constructed and used to measure proportional counter parameters in the ultrasoft x-ray region at atmospheric and subatmospheric pressures for counting gases of P-10 and methane. We find that at atmospheric pressures the parametrization given by Zastawny for describing gas amplification in proportional counters applies and have measured values for the parameters for P-10 and methane. For subatmospheric pressures the Zastawny parameters are inadequate. A new parametrizatlon is required. In addition, the linearity of the detector for x-rays of energies of 15 KeV to 0.5 KeV was measured for pressures ranging from 750 Torr to 150 Torr and found to be excellent in all pressure regions.
In Vivo Analysis of Lipid-Protein Ratios in Human Muscle by Differential X-Ray Absorption Using 109Cd Photons
Authors: Preuss Luther E. , Bolin Frank P. 
Published: March 2019

AbstractTissue's two major components: lipid and protein, are of a primary importance, related as they are to the normal life states. Assay of protein and lipid (fat and lean) in vivo is of certain criticality in human disease states, such as wasting, edema, obesity and other dyscrasias involving body mass and fat-lean balance. Since the elemental composition of lipid and protein molecules differ in a significant and regular fashion, their mass absorption coefficients differ when radiation in the x-ray and lower energy gamma ray region is used. Two monochromatic photons, one in the 20 to 30 keV region, another in the 60 to 100 keV region, can be shown to exhibit an absorption ratio in a two component system of fat and lean which provides for a determination of the component mass ratios. Photons from x-ray machines and isotopic x- and gamma ray sources have been proposed for this. The radionuclide offers qualities of stability, small size and weight, portability, zero power consumption and, generally, a certain economy. The electron capture decay of 109Cd provides a gamma ray at 88 kilovolts and a daughter (Ag) Kα doublet at 22 keV. This fortuitous energy combination is advantageous in this differential absorptiometry. The 109Cd source provides for a stable geometry and calls for the simultaneous measurement of both photons by non-dispersive x-ray spectroscopic techniques. Ten mCi of 109Cd was incorporated into a sealed source, filtered for the silver Kβ1 x-ray (at 24. 942 keV) with 0. 1 mm palladium and collimated with a grazing aperture arrangement. Fat-lean tissue simulating standard samples three cm to ten cm in length and of various component ratios were studied. Component weight percent was determined using a function of the transmitted radiation. Determinations on water (the lean simulator) and polyethylene (the fat Simulator) as well as other materials produced absorption ratios concurring favorably with the known make-up of the Simulators.In vitro dual beam analysis of muscle tissue samples showed a high degree of correlation with the results of ether lipid extractions. Using lipid extraction values as the standard, the x-ray absorptiometric technique produced percentage lipid levels averaging within 0. 5% of the extractions.In vivo measurements of fat content of the triceps muscle area were compared with skinfold thickness measurements of the same area. Coefficient of correlation was 0. 88.
Miniature X-Ray Equipment for Diffraction and Fluorescence Analysis
Authors: Herglotz H. K. 
Published: March 2019

AbstractEnergy yields in the generafion of monochromatic X-rays by electron bombardment are poor and the utilization of X-rays is even more wasteful, particularly in X-ray diffraction. Only a small stereoangle of radiation issuing from a flat target passes through the collimator of a camera.An end-window X-ray tube using a conical cavity as a target is more economical, since there is a finite probability of several excitation acts by one electron in the cavity. A major part of the radiation emerges from the tube in a stereoangle of ≈ 0.02 instead of 2π steradian. This and the proximity of the tube focus to the sample are favorable for X-ray diffraction, as will be demonstrated in several examples. The geometry and performance of the tube are also expected to provide a superior replacement for the weak isotopic sources normally used in energy dispersive analysis.Several versions of the tube, covered by U.S. Patent 3,584,219, H. K. Herglotz and C. D. Reilly, are described. Of particular interesf for X-ray diffraction is a double cavity tube with 2 exit ports. The Iow power consumption of the tubes (35 kV, 1 mA or less) requires only a small power supply. All equipmenf for XRD work including batteries can be accommodated in a suitcase and therefore lends itself to field use by mineralogists, for example, or in materials testing.
A Rapid Fluorescence and Energy Powder Pattern Analysis System
Authors: Lin Wen 
Published: March 2019

AbstractReported here is a computer-coupled energy dispersive x-ray system capable of performing rapid elemental analysis and phase identification employing fluorescence and energy powder pattern analyses, The system consists of a Si(Li) detector, commercial diffractometer, vacuum specimen chamber with fluorescsnce geometry and a multichannel analyzer interfaced to a laboratory computer.The continuous radiation is used to excite both fluorescent x-rays and Bragg reflections. The diffractometer spectrum obtained with a fixed 2θ setting gives the crystalline diffraction pattern plus the detectable emission lines. With the fluorescence geometry, the system is capable of detecting the characteristic x-rays of the elements down to Na. The fluorescent spectrum can be used to separate the diffraction peaks from the emission lines in the diffractometer spectrum. Furthermore, the fluorescent spectrum can be used for qualitative or/and quantitative elemental analysis.Software was developed for element recognition, to isolate the diffraction pattern from emission lines, d-spacing calculations, as well as matrix corrections and mass fraction determination of elements in quantitative analysis.
Use of an Automated Powder Diffractometer for the Analysis of Rock Samples
Authors: Jenkins R. , Westberg R.G. 
Published: March 2019

We have recently described an automated powder diffractometer, the APD-3500, in which a small (4K x 18 bit) minicomputer is utilized for hardware control and data processing. Among the software programs developed for this system is a “Peak Search“ routine which is designed to record a diffraction pattern with optimum, use of scanning time and to give output directly in J.C.P.D.S. Powder Data File Format. Optimum use of scanning time is achieved by a double-pass System in which a first (rapid) pass is made to establish significant data.A second routine is a “Line Profile” routine which gives the choice of rapid slewing or slow Step scanning of the goniometer between selected angular ranges. The routine thus allows the controlled stepping of the goniometer between selected angular ranges giving incremental and integral, background corrected counts. An automatic internal and/or external calibration capability makes this particular mode ideal for quantitative analysis.
The Asymmetric Bragg Reflection and its Application in Double Diffractometry
Authors: Renninger M. 
Published: March 2019

AbstractGuided by the dispersion, surface of dynamical theory, we easily obtain evidence of the fact that in asymmetrical surface reflections (Bragg case) of X-rays at a perfect crystal, the angular widths of the incident and reflected beams are different from the same widths in the symmetrical Bragg case. The beam with the smaller glancing angle to the surface is angularly expanded, the other one, contracted (though in cross section, the former is contracted and the latter, expanded). Consequently, if the incident glancing angle is the smaller one (striping incidence, Vreftection), the angular width of the reflected beam is smaller than in the symmetric case (S-reflection), and that of the reflected section out of the primary beam is greater, and vice versa (striping emergence, if-reflection). At striping incidence, a contraction occurs, whereas at striping emergence, expansion of the angular reflection range occurs. These facts offer a number of possibilities for applying asymmetrical reflections to the well-known technique of the two crystal diffractometer—the author proposes the term “diffractometer” instead of the widely used “spectrometer”—in the (nv, −n)-position. These possibilities extend the efficiency of the double diffractometer with multiple effects, and some of them are given below: (1) Realization of rocking curves of extremely small angular width in the (nv, −nR)-position, and consequently increased sensibility of that width to lattice distortions, (2) Use of the extremely small angular width (or more strictly, the sharp θ-λ-coordination) of the beam emerging from a first crystal. This is in V-reflection for scanning the intrinsic diffraction pattern of the second crystal used in S- or V-reflection [(nv, −ns) or (nv, −nv) -position], (3) Increased steepness of the sides of the rocking curves using (nv, −nR) or (nv, −ns)-positions which allows double diffractometric topography (Bond-Andrus, Bonse-Kappler) of increased angular resolving power. (4) Repeated ^-reflections (eventually within a single crystal provided with a suitable groove) leading to further angular contraction of the resulting reflected beam and therefore further increased angular resolving power [(nv, −nv, nR, −nR)- and (nv, −nv, +nS)-positions]. Here the tails of the rocking curve are also suppressed by multiple reflection (Bonse-Hart).
The Dilemma of Anomalous X-Ray Reflections
Authors: McGee James F. , Olli Veil I. 
Published: March 2019

AbstractThat X-rays focused by reflection from concave surfaces exhibit anomalous image broadening was shown by Ehrenberg using a line source. Even flat nonfocusing surfaces of many different materials produced an anomalous striated reflection. According to Ehrenbevg, the common cause for the observed broadening in the focused image and the striated pattern in the nonfocused reflection is a periodic surface structure. In later years, Eliot, using a point source of X-rays reflected from a concave surface, observed a striated pattern at a position well beyond the focal plane. It is to be noted that Eliot's experiment combined elements of Ehrenberg's two experiments—a focusing surface and observations made far from any focal plane, real or virtual. Eliot observed his striations with fused silica surfaces but not with obsidian. Recently, Yoneda, using X-rays collimated by a Soller slit and incident on a plane surface, observed an anomalous line reflection not previously reported.Various experiments performed by the present authors have attempted to duplicate some of the above situations as closely as possible, either directly with X-rays or in an analogous manner with visibic light. It will be shown that satisfactory explanations can be formulated from previously unsuspected diffraction phenomena, recently confirmed by experiment as well as by a simple experimental oversight. In spite of the dilemma presented, either horn eliminates all previous limitations due to surface conditions, so that the tolerable surface roughness is once again determined by the well-known Rayleigh criterion rather than by any periodic surface irregularities introduced through the polishing process or by nature.
A Study of the Unusual Line Structure in Powder Patterns of Pyrolytically Deposited Boron Compounds and Other Materials
Authors: Prickett Robert L. , Hough R. L. , Earley Duane 
Published: March 2019

AbstractA prolonged study has been roade of the unusual X-ray powder patterns generated by certain pyrolytically formed boron compounds, consisting of two to four moderately broad diffraction lines in the 1-4 Å range. These broad lines are unexpectedly made to disappear by a singie sharp blow with a hammer on the specimen in a Plattner diamond mortar, the disappearance being accompanied by the spontaneous generation of the standard diffraction lines expected for normally crystalline materials. The same diffraction pattern changes also may be brought about by regular grinding methods, fracture, or thermal annealing. Transmission electron diffraction yields results identical with those obtained by X-ray. Orientation studies demonstrate that the phenomenon is not orientation dependent. Controlled fracture has been applied in an attempt to develop a hypothesis. It appears from the constancy of the width and position of the diffraction lines among samples that the phenomenon being studied has a definite potential energy, well located somewhere between amorphous and crystalline states. Demonstration of this phenomenon of line broadening has been obtained with boron, boron carbide, and in part with silicon, carbide. These materials have been formed by various methods: pyrolytic decomposition of carborane, low pressure electrical discharge in diborane, chemical reaction between boron halide and hydrogen.
Anomalous Residual Stresses
Authors: Ricklefs R. E. , Evans W. P. 
Published: March 2019

AbstractResidual stresses were measured in hardened and tempered specimens after unidirectional plastic extension. X-ray and strain gage-layer removal methods were compared. Anomalous residual stresses were found in extended samples at hardnesses of Rc 32–35. The X-ray method indicated compressive residual stresses of nearly constant magnitude through ⅓ the thickness of flat samples, while the strain gagelayer removal method indicated that no macrostress existed. A constant anomalous residual stress was also seen by X-ray through ⅗ the thickness of a cylindrical specimen deformed uniformly in tension. Little or no anomalous stress was found in an extended specimen at Re 55 or in a specimen at Rc 44 after uniform bending.
Experimental Factors Concerning X-Ray Residual Stress Measurements in High-Strength Aluminum Alloys
Authors: Hilley Michael E. , Wert James J. , Goodrich Robert S. 
Published: March 2019

AbstractX-ray diffraction as a means of determining stresses has found increasing application in the last few years. This is primarily because it is the only technique by which stresses can be determined without making measurements on the specimen or structure in the unstressed condition and, consequently, it is the only truly nondestructive technique for determining residual stresses. The principles of determining macrostresses on surfaces with commercially available equipment is quite well known and employs either the X-ray diffractometer or back-reflect ion camera techniques. The diffractometer technique was selected for this investigation because of its accuracy and because it allows both macrostresses and microstra in to be analyzed from the change in position and shape of the diffraction peaks. The X-ray analysis actually consisted of two separate phases. The first dealt with the X-ray determination of the elastic constants (Young's modulus and Poisson 's ratio) for several aluminum alloys, including 5083. These values were compared with the theoretical or published values as determined by standard tensile tests and used later in stress calculations. For these tests, a unique stress stage was used which allowed the specimen to be stressed while positioned in the diffractometer, and also have angular rotation about the diffractometer axis that is independent of the rotation of the counter and receiving slit system. The second phase consisted of analyzing different groups of 5083—aluminum alloy specimens which had been subjected to various degrees of cold working by rolling. This analysis consisted not only of the computation of macrostresses, but also of microstrain and change in particle size as a function of percentage reduction in thickness. The final portion of this phase dealt with electro polishing successive layers from the surface of each sample and relating the measured relaxation to the thickness of the layers removed. In this way, stress distribution in depth was obtainable as a function of cold working.
X-Ray Analysis of Fatigue Damage in Copper
Authors: Baggerly Roy G. , Pelloux Regis M. N. , Flanagan William F. 
Published: March 2019

AbstractA Warren-Averbach1-4 X-ray line profile analysis was applied to broadened X-ray diffraction peaks from copper deformed in fatigue. The copper specimens were fatigued by four-point bending at peak-strain amplitudes between 0.00105 and 0.00442 in./in., and measurements were made at various fractions of the total fatigue life. The analysis results in an estimation of (a) an average coherently diffracting domain size normal to the diffracting planes and (b) an rms strain distribution function where the strain normal to the diffracting planes is averaged over a given distance at all points in the diffracting crystals and expressed as a function of averaging distance.Prior to fatigue cycling, the annealed copper exhibited extinction, which reduced the integrated intensity from the low-angle reflections. After fatigue cycling, the integrated intensity increased with increasing strain amplitude of fatigue. The integrated intensities and the rms strains were established during the first few percent of the fatigue life and were found to increase with fatigue strain amplitude. The measured strains were larger in the <100> direction than in the <111> direction, but the absolute values were small. On the basis of transmission electron microscopy of thin foils, these results may be explained by assuming the strains are due to the presence of numerous dislocation dipoles.
Improvement of Accuracy in Representation of Conventional Pole Figures
Authors: Aoki K. , Hayami S. , Matsuo M. 
Published: March 2019

AbstractIn the conventional pole figure, an accurate representation can be attained by correcting the observed X-ray diffraction intensity for any change in diffraction geometry and by comparing this with the correctly established standard intensity. For the intensity corrections, ASTM has prescribed the method of Decker et al. In practice, however, the validity of the correction formula is uncertain, since the prerequisite is difficult to attain for parallelism of an incident beam of sufficient intensity. For the standard intensity, it is desirable to take the intensity obtained with the randomly oriented material of the same composition. However, in most cases an arbitrary unit has been taken because of the difficulty in getting a truly random and uniform sample. Under these circumstances, it is first necessary for an accurate representation of pole figures to make a random sample of uniform thickness for the standard. The authors have obtained satisfactory standard samples by sintering the randomly oriented iron powder made from iron chloride and made use of them to check the method of intensity correction. Satisfactory results are obtained in the randomness tests, such as the comparison of the relative intensity diffracted from the crystal planes parallel to the sample surface and the fluctuation of diffraction intensity during α rotation.In the reflection case by the Schulz method, the (110) reflection intensity of a random sample, by Co Kα radiation, is independent of the tilting angle up to 50°. The other reflections do not give a constant intensity for the wide range of the tilting angles because of dispersion of the diffracted beam due to the wider separation of Kα doublet in the higher reflection angle and the wider irradiated area at the lower angles. In the transmission case Schulz's correction formula is in good agreement with the observed values for the various diffraction lines and the samples of various µt, while the Decker-Harker formula does not give the absorption change with α-rotation even by an incident beam of ⅙° divergence. In both cases, an accurate determination of pole densities is made by comparing the diffraction intensity of the standard sample substituted in place of the test specimen and by correcting the absorption change due to the difference of µt between the standard and test sample, which affords good coincidence in the overlapped region. The pole figure obtained by the above method furnishes an accurate prediction of plastic and elastic anisotropy in sheet metals.