bluuebunny/crossref_metadata_2025 huggingface dataset:
Vinyl—a new blow molding polymer
Authors: Kochanski James W.
Published: May 2005

Vinyl is used in a wide range of applications, not only in packaging but also in construction, automotive, and other areas. Vinyl (polyvinyl chloride, or PVC) has maintained a significant presence in some markets for more than 30 years. Yet vinyl is not necessarily on the downward leg of its product life cycle. New, more effective PVC blow molding compounds are being developed and introduced. These versatile new polymers are extending the life cycle of vinyl packaging into the 21st century. The long‐standing success of vinyl in bottle applications is due to a number of key properties, including its chemical resistance, UV stability, low mold costs, design flexibility, low permeability, and aesthetics. In recent years, improved PVC compounds have created new growth markets for vinyl. Three important ones are hot‐fill applications, personal care products, and bottled water. The potential of vinyl bottles to become a major factor in the fast‐growing bottled water market is a particularly good example of the adaptability and versatility that make vinyl one of the most exciting “new” blow molding polymers.
Plasticizers: A consideration of their impact on health and the environment
Authors: Cadogan D. F.
Published: May 2005

Plasticizers have been used for centuries to improve the processability and flexibility of a variety of materials. At the dawn of civilization water was used to plasticize clay for the production of pottery and clay tablets and the Ark was reputedly waterproofed with pitch plasticized with oil. Today the most common plasticizers are phthalates, adipates, and similar esters the majority of which are used to produce flexible PVC products. The widespread use of plasticizers in these applications over the last forty years has resulted in their toxicology being extensively researched and understood. As a consequence of these investigations many official bodies and legislative authorities have concluded that plasticizers pose no significant hazard to man or the environment. Plasticizers will, therefore, continue to be used to enhance all our lives through the production of a wide variety of PVC items ranging from medical components to waterproof clothing and floor coverings.
Evaluation of secondary lubricants for rigid PVC extrusion
Authors: Hughes Paul C. , Mieure K. G.
Published: May 2005

A common system of primary lubricants in rigid PVC extrusion compounds is calcium stearate plus paraffin wax. Secondary lubricants are frequently added to this system at low concentrations with the intention of improving such properties as metal release, thermal stability, plateout, extrudate surface appearance, etc. This paper discusses the results of laboratory studies designed to evaluate the contribution to these properties of two commonly used secondary lubricants: AC629A, an oxidized low molecular weight polyethylene, and K175, an acrylic “lubricating processing aid.” Surprisingly, the testing showed little improvement in performance when these auxiliary lubricants were added.
Testing variability in viscosity measurements of PVC plastisols
Authors: Breslin Bridget K. , Moran Michael T.
Published: May 2005

An experiment was conducted to compare the variability of the Brookfield Viscometer, the Severs Extrusion Rheometer, and the Haake Rotational Viscometer in measuring flow characteristics of PVC plastisol. The author discusses variability of the different test methods involved with the Severs and the Haake viscometers. Also discussed are operator, environmental, and day‐to‐day variation.
The use of statistical process control in batch processed PVC compounding
Authors: Brown David J.
Published: May 2005

This paper describes the main Statistical Process Control (SPC) method that is being used by Canada Wire and Cable in the manufacture of their flexible PVC compounds. It outlines the benefits that are being realized by following a systematic approach towards using control charts. By employing SPC as a quality improvement tool, the operation has reduced its costs by an estimated $180,000 per year.
Processing morphology of PVC/MBS blend
Authors: Kadokura M. , Momii T. , Hirata H. , Okuda Y. , Kobayashi H.
Published: May 2005

MBS resin, an impact modifier for PVC, plays an important role in PVC processing, the details of which, however, are not well understood. The use of a temperature programmable Brabender Plasticorder and new microscopic techniques have revealed that MBS inhibits the comminution of PVC grain in the initial stage of processing, and PVC breakdown occurs after the MBS melts. Dynamic melting of MBS is observed as a Brabender torque peak. These characteristics of PVC/MBS blends are quite different from those of PVC/processing aid blends. Processing features of PVC/MBS blends are reported and compared with those of PVC/processing aid blends.
UV protecting layers on PVC made by plasma polymerization
Authors: Leiber J. , Michaeli W. , Telgenbüscher K. , Stollenwerk M.
Published: May 2005

UV protection is necessary for many plastics if they are to be used for outdoor applications. Plasma polymerization, a new surface coating technology, permits the depositing of thin polymer layers on plastics as UV and weather protection. With these layers, even the UV resistance of polyvinylchloride (PVC) containing a conventional UV stabilizer can be improved; After a QUV panel test of 5000 h the plasma polymerized films show a decrease in the degree of yellowing by a factor of 3 compared to the uncoated samples. Different types of monomers and other process parameters of the plasma polymerization apparatus show a significant influence on deposition rates, surface chemistry, and UV protecting properties.
Blends and alloys of vinyl—technology and applications
Authors: Asay R. Elliott , Hein Marc D. , Wharry Don L.
Published: May 2005

The use of multiphase polymers is of growing importance because of their inherent economical and technological benefits. The basic characteristics of multiphase polymer blends and alloys are covered. The advantages of vinyl as a component are discussed in light of its ease of processing, inherent compatibility, fire resistance, weatherability, and a wide range of properties achievable. Blend morphology is reviewed and related to the mechanical properties. Typical examples of commercial materials and their application are reviewed.
The effect of reprocessing on the properties of PVC
Authors: Covas J. A. , Silva C. A.
Published: May 2005

The effects of reprocessing on the mechanical, physical, and rheological properties of a commercial plasticized PVC compound are investigated. Reprocessing experiments at lower, identical, and higher temperatures than those attained during the initial extrusion in a capillary rheometer are undertaken. Repetitive reprocessing is also considered. With the exception of the mean surface roughness—and when the effects of degradation are discarded—the other characteristics of processed and reprocessed PVC are essentially similar. Nevertheless, changes at both the molecular and the morphological level take place during reprocessing, as demonstrated by the results of thermal analysis and surface appearance.
Rheological properties of polyvinylidene fluoride and polymethyl methacrylate engineering alloys
Authors: Burke Dennis Michael
Published: May 2005

Recent concerns over smoke toxicity and optical properties have forced the electrical/electronics industries, particularly the wire and cable and fiber‐optics industries, to focus attention on the development of new materials. The demands are critical for these applications and include not only optical and flammability properties but also thermal and mechanical properties, and, of course, processability. Acrylic‐fluoroplastic alloys are exceptional candidates for meeting such requirements. Along with various optical evaluation and traditional mechanical testing, dynamic mechanical testing (DMT) procedures, as specified by ASTM protocols, can be used to evaluate, qualify, and quantify alloys for their end‐use properties and processability. Specifically, this paper shows how DMT can be used to monitor both the solid and melt rheological properties of several PMMA/PVDF alloys. Important results of this study include the evaluation of compatibility/miscibility, modulus as a function of temperature, melt viscosity as a function of shear rate, and melt viscosity as a function of temperature.
Non‐lead stabilizer systems for PVC wire and cable extrusion (an update)
Authors: Kaseler Thomas G.
Published: May 2005

Recent introduction of non‐lead stabilizer systems to the wire and cable industry have shown a rising interest in these new products. Based on new regulations on the usage of lead stabilizers and the difficulties of disposing of vinyl containing lead in regular landfills, the interest to replace these products is in fact very high. The objective of this paper is to show what non‐lead systems are currently available and where their strengths and weaknesses are. Test results of laboratory studies are presented comparing environmentally and physiologically acceptable Ca/Zn, Mg/Zn, and Ca/Al/Zn stabilizer systems to conventional lead compounds in typical wire and cable formulations. In addition, data are presented on products that are already in use commercially.
Environmental stress cracking of polyvinyl chloride compounds under long‐term stress
Authors: Summers James W. , Rabinovitch Elvira B. , Rodriguez Juan
Published: May 2005

Polyvinyl chloride compounds rupture prematurely in contact with environmental stress cracking (ESC) agents such as plasticizers. This effect shows a considerable deviation in a stress rupture plot (log stress vs log time) from the expected stress rupture in the absence of ESC agents. PVC and polymers in general dilate under a stress, increase free volume, and allow diffusion of the ESC agent and plasticization of the polymer. However, we show ESC failure is not dependent alone on molecular size of the ESC agent when comparing di‐2‐ethylhexyl adipate (DOA), di‐2‐ethylhexyl phthalate (DOP), and tri‐2‐ethylhexyl trimelitate (TOTM). Therefore this suggests that ESC failure is not strictly associated with diffusion of the ESC agent into the free volume of the PVC, but rather flaws and stress concentrations play a large role. Higher molecular weight PVC retards rupture, both in air and in contact with the ESC agent. However, the safe way to design PVC parts is to avoid ESC contact with stressed PVC rather than using high molecular weight PVC. Part design can play an important role in preventing these premature failures by keeping the ESC agent away from contact with stressed PVC.
Understanding the functions of acrylic processing aids in rigid PVC injection molding
Authors: Stevenson Janis C. , Einhorn Richard A.
Published: May 2005

Poly(vinyl chloride) (PVC) compound use is growing in specialty injection molding applications such as appliances, business equipment, and electrical enclosures. A key factor in determining the appearance and physical properties of the molded parts is the processability of the PVC compounds, which can be improved through the use of acrylic processing aids. Processing aids promote PVC fusion, modify the melt rheology, and/or provide lubrication. Some processing aid products are designed to serve one of these functions while others provide a combination of functions. Each of these functions and its major benefits in rigid PVC injection molding are described. Some guidelines for selecting appropriate processing aid products for applications are provided.
The effect of the FTC environmental guidelines on the marketing of vinyl products
Authors: Rakus J. P.
Published: May 2005

In July 1992, the U.S. Federal Trade Commission (FTC) issued its long awaited guidelines on the use of environmental marketing claims. These guidelines do not carry the force of law, but they may result in law enforcement action if such claims are found to constitute deceptive advertising. The paper examines the effect the FTC guidelines will have on the marketing of vinyl products. It briefly describes the general principles that apply to all environmental marketing claims and then discusses the eight specific claim types covered by the FTC document: general environmental benefits, degradability, compostability, recyclability, recycled content, source reduction, refillability, and ozone friendliness.
Increasing of PVC resin bulk density and free flow by treatment with organic compounds
Authors: Zilberman E. N. , Lerner F.
Published: May 2005

The ability of different organic additives to increase the bulk density (BD) and the free flow (FF) of PVC was investigated. PVC was treated by quarternary ammonium salts, low‐molecular glycols, polyethylene glycols, polyethylene wax, stearic acid, butyl stearate, oxyethylated fatty acids and alcohol, non‐oxyethylated and oxyethylated partial fatty acid esters of polyhydric alcohols. Increasing one of the mentioned values is not always accompanied by increasing the other. There exist additives which increase the BD only, the FF only, and both values simulataneously. The BD of treated PVC is often instable; it may increase and decrease on standing. The additives used do not affect the structure of PVC particles, but may change the volume of external voids between them. The efficiency of each additive depends on its polarity and structure of the chains. The mechanism of the action of additives altering the BD and FF was considered. It was expected that the additives leading to denser packing of the PVC powder reduce the interparticle interaction at the expense of particle‐additive interaction.
Aspects of miscibility in poly(vinyl chloride)/epoxidized natural rubber blends. Part II: Dynamic mechanical properties
Authors: Ishiaku U. S. , Nasir M. , Ishak Z. A. Mohd
Published: May 2005

Miscibility in poly(vinyl chloride)/epoxidized natural rubber (PVC/ENR) blends was further investigated by means of dynamic mechanical analysis. The single glass transition temperature shown by the blends supported earlier observations of miscibility Furthermore, observed synergism in storage modulus has again reaffirmed the miscibility of these blends. A critical examination of the damping peaks at various compositions again revealed the microheterogeneous nature of the blends. Some theories relating glass transition temperature and modulus with miscibility were also used to examine miscibility. Agreement of the results with theories proposed by Gordon—Taylor and Kleiner has provided a further insight into the miscible nature of PVC/ENR blends.
A simple method to evaluate the matrix effects in X‐Ray fluorescence analysis
Authors: Franzini M. , Leoni L. , Saitta M.
Published: May 2005

In X‐ray fluorescence analyses, the matrix effects can be evaluated by computing appropriate coefficients. Utilising powder pellets of samples artificially prepared, a method for computing the matrix effects coefficient of H2O, Na2O, MgO, Al2O3, SiO2, K2O, CaO, TiO2, Fe2O3 for the analytical lines of thirteen elements: vanadium, chromium, nickel, copper, zinc, gallium, rubidium, strontium, zirconium, barium, lanthanum, cerium and lead is described. The computed coefficients have been used to analyse six international rock standards (the U.S. Geological Survey Standards: G‐2, GSP‐1, AGV‐1, BCR‐1, PCC‐1, DTS‐1).
X‐ray fluorescence determination of sodium in silicate standards using direct dilution and dilution fusion preparation techniques
Authors: Fabbi B. P.
Published: May 2005

Direct dilution of a sample with an equal proportion of cellulose binder and dilution fusion of one part of sample with fourteen parts of LiBO2 flux has been used to prepare pelletized samples of silicate standards for determining sodium by X‐ray fluorescence analysis. An RAP analysing crystal was used to disperse and reflect the sodium spectra. Detection limits were found to be 0.07 and 0.39% Na2O at the 2s̀ confidence level for the direct dilution and dilution fusion preparation techniques, respectively.
Determination of silver in photographic materials by energy dispersive X‐ray fluorescence analysis
Authors: Ehn E.
Published: May 2005

Isotope excited energy‐dispersive X‐ray fluorescence determination of silver in photographic materials yields poor reproducibility because of difficulties in reproducing the geometry. By placing the film sample between the detector and the radioactive source this difficulty is overcome. The theory of such an arrangement indicates that effects due to varying thickness of film base or unequal coating in the case of double‐coated film play a minor role. The suggested improvements in measuring geometry should be of value for any application in which samples are in the form of thin foils or sheets.
An accurate fusion method for the analysis of rocks and chemically related materials by X‐ray fluorescence spectrometry
Authors: Harvey P. K. , Taylor D. M. , Hendry R. D. , Bancroft F.
Published: May 2005

This account describes a rapid and accurate fusion technique of X‐ray fluorescence analysis that is based on the method of Norrish and Hutton,1 but modified from the latter in a number of respects to enable more rapid preparation and processing of samples without any loss of accuracy. The technique allows a wide range of materials to be analysed including silicate rocks and minerals, cements, bricks, carbonates, evaporites, soils and some ores.
The intensity ratio between the line and white spectra from a chromium target spectrographic X‐ray tube
Authors: Castellano E. E. , Alvarez A. G. , Andrieu J. M.
Published: May 2005

The ratio of the total characteristic to white radiation from a chromium target spectrographic X‐ray tube has been determined by a new method at operating voltages ranging from 10 to 50 kV. The ratio values K are referred to the portion of the continuous spectrum extended from the Duane and Hunt limit λo to 2.5 Å A conversion coefficient has been tabulated to consider the continuous spectrum extended from λ to any arbitrary wavelength up to 6 Å. The method can be conveniently applied to targets other than chromium. It is only required to perform a simple fluorescence intensity measurement with a standard spectrometer on a conveniently prepared sample.
X‐ray fluorescence analysis — results of a first round intercomparison study
Authors: Camp D. C. , Cooper J. A. , Rhodes J. R.
Published: May 2005

The results are presented of an intercomparison study between twelve investigators and three analytical techniques. The objective was to determine the precision and accuracy with which multi‐element analysis of air particulates on filters can be accomplished using energy dispersive X‐ray fluorescence spectrometry. Special emphasis was placed on testing calibration techniques and methods of correction for absorption in both particulate deposits and substrates. Results indicate that errors in calibration and correcting for substrate absorption can be reduced to much less than 10% for elements K and above, but the more work is required to test methods of correcting for particles size to achieve 10% accuracy at energies below 3 keV.
A versatile thin film method for quantitative X‐ray emission analysis
Authors: Chung Frank H. , Lentz August J. , Scott Richard W.
Published: May 2005

Liebhafsky and Zemany proposed two terms in X‐ray emission analysis: one is the linear thickness of a specimen below which the absorption effect vanishes; the other is the critical thickness of a specimen above which the specimen becomes infinitely thick. The criteria for these two terms are defined here in quantitative terms. A procedure for making thin films of closely controlled thickness is described. The sample is dispersed into a film‐forming polymer solution which contains an internal standard element. A thin film is made of this suspensoid by a film applicator. The internal standard element is used to correct for variation in actual film thickness. A single calibration curve can be used for samples of different matrices. Experimental data are presented to demonstrate the effectiveness of this thin‐film method in eliminating matrix effects.
Charateristic of the Ge(111) analyser crystal
Authors: O'Connell A. M.
Published: May 2005

Measurements on several Ge(111) crystals have shown a variation of a factor of two in their reflectivity for p Kα radiation. High background readings for phosphorous using the Ge(111) crystal are shown to be due to germanium L spectra fluorescence from the crystal. The background can be reduced by almost a factor of four without appreciably diminishing the net P Kα count rate by selecting the optimum setting of the pulse height analyser.
X‐ray mass absorption coefficient measurements for aluminium in the range 1.9 to 9.9 Å
Authors: Short M. A. , Tabock J.
Published: May 2005

X‐ray mass absorption coefficients for aluminium have been measured for nine wavelengths in the range 1.9 to 9.9 Å. The values obtained disagree with many published compendia of mass absorption coefficients, but agree well with some published experimental values.
Analysis of the heavy element content of atmospheric particulate fractions using X‐ray fluorescence spectrometry
Authors: O'Connor B. H. , Kerrigan G. C. , Thomas W. W. , Gasseng R.
Published: May 2005

Techniques have been developed for analysing the heavy element content of atmospheric particulate fractions by means of X‐ray fluorescence spectrometry. Special attention is devoted to the nondestructive analysis of particulates collected on the cellulose and fibreglass filters used in high volume air samplers. It is shown that the X‐ray fluorescence data must be corrected for absorption of radiation by the filter medium in the case of cellulose due to penetration of the particulates into the body of the filter. Fibreglass is shown to be superior to cellulose in that most of the particulates are trapped near the surface of the paper. A novel feature of the analytical method described is that a comparison of X‐ray fluorescence intensities from the front and back of the filter leads to a determination of filter collection efficiency. A second method for determining collection efficiency, using a tandem arrangement of filter papers, is also described.
Experimental verification of the X‐ray absorption correction in aerosol loaded filters
Authors: Adams F. C. , Billiet J.
Published: May 2005

Correction for the absorption of the X‐rays in aerosol loaded filters can be based on the measurement of the front‐to‐back intensity ratio. Experimental verification that an accurate and precise absorption correction can be obtained is given. The ‘two‐lines’ method based on the accurate measurement of the lead Mα to Lβ intensity ratio in actual samples is used. The distribution of the aerosol in the filter is exponential with a variable gradient.
Intra‐ and inter‐spectrometer correction coefficients for X‐ray emission spectrometric calibration equations
Authors: Clark N. H. , Mitchell R. J.
Published: May 2005

The calculation and use of spectrometer‐dependent variables for use in calibration equations converting X‐ray intensities to concentrations are described. The variables correct for changes in both sensitivity and background, allow common calibration equations to be used for two spectrometers and obviate the need for recalibration.
Routine use of a second‐generation windowless detector for energy‐dispersive ultra‐light element X‐ray analysis
Authors: Russ J. C. , Baerwaldt G. C. , McMillan W. R.
Published: May 2005

The second‐generation design of this removable‐window detector assures reliable routine operation, and minimizes operating limitations by providing protection against electrons, light photons and contamination molecules entering the detecting unit. The extensible design allows practical optimization of detector position.

The inherent limitations of ultra‐low energy X‐ray analysis must be understood by the user. They include problems of peak identification and sample preparation, but can be dealt with by intelligent operation and data interpretation.

Practical analytical results, both qualitative and quantitative, can be obtained. In particular, the software proven successful for dealing with ‘normal’ spectra can be adapted and used for ultra‐low energies.
A method of correction for absorption matrix effects in samples of ‘intermediate’ thickness in EDXRF analysis
Authors: Markowicz Andrzej
Published: May 2005

Theoretical grounds for a method of the elimination of absorption matrix effects based upon the application of the measurement of the intensity of the coherent scattered and Compton scattered X‐rays are presented in this paper. The presented method has been confirmed experimentally. The described method of the elimination of the absorption matrix effect can be applied, in the case of samples having ‘intermediate’ masses per unit area, by means of analysis by the X‐ray fluorescence method. The total error (standard deviation) of correction for absorption obtained by the proposed method varies from 3–7% for the values of this correction from 2.5–1.3 respectively. The presented method can be used in the trace analysis of biological and environmental materials.
X‐ray fluorescence investigation of the shroud of turin
Authors: Morris R. A. , Schwalbe L. A. , London J. R.
Published: May 2005

We present results of X‐ray fluorescence measurements on the Shroud of Turin. Quantitative estimates are given for the observed trace quantities of calcium, iron and strontium, and detection limits are established for other elements of potential interest. The calcium and strontium appear as uniform background distributions. Iron traces are observed in all of the data spectra but their local concentrations vary. Comparisons between image and off‐image areas reveal no differences, within the precision limits of the data, that would indicate the presence of pigments or dyes containing high‐C elements. In ‘blood’ stain regions the measurements show significantly higher concentrations of iron. However, the data do not allow a unique identification of the stain's origin. Quantitative comparisons are made between the shroud results and similar measurements on whole blood and Fe2O3 stains.
X‐ray fluorescence analysis using intensive linear polarized monochromatic x‐rays after bragg reflection
Authors: Wobrauschek P. , Aiginger H.
Published: May 2005

To obtain intense linear polarized monochromatic X‐rays a single crystal where Bragg reflection occurs at an angle 2θ=90° is used. A number of suitable crystal materials is listed which fulfil the requirements of the Bragg equation for the wavelengths of standard X‐ray tubes and the angular condition. As the first result of a new construction a detection limit of 1 ng Ca was determined using a Cr anode and a Ta single crystal (002) plane as polarizer.
Calculation of sample absorption by means of compton scattering in X‐ray diffraction analysis
Authors: Bar‐On P. , Zevin L. , Lach S.
Published: May 2005

A method of absorption correction in X‐ray diffraction (XRD) phase analysis, based on measurements of Compton scattering, is described. Compton scattering of Mo Kα was measured and Cu Kα was used for XRD analysis. Under these conditions, the method is valid for phase analysis of silicate and carbonate rocks. Quartz content was determined in 13 samples by the proposed method and the conventional method of internal standard. The two sets of results are in a good agreement.
A standard technique for measuring window absorption and other efficiency losses in semiconductor energy‐dispersive X‐ray spectrometry
Authors: Stone R. E. , Walter F. J. , Blackburn D. H. , Pella P. , Kraner H. W.
Published: May 2005

A Standard technique for measuring window absorption and other efficiency losses in semiconductor X‐ray spectrometers is described. This technique is in the process of being adopted as an IEEE and IEC standard. A NBS standard reference material glass, SRM‐477, has been developed to promote broad availability for the standard method throughout the user community. Measurements are reported which have been made to establish limits on the geometry of the technique and to determine the effectiveness of the method.
Comprehensive major and trace element analysis of geological material by x‐ray fluorescence, using low dilution fusions
Authors: Lee R. F. , McConchie D. M.
Published: May 2005

A rapid method of routine whole rock analyses of major and trace elements, using low dilution fusions, is described. The method is particularly suited to use with automated x‐ray fluorescence equipment, and is effective for rocks which range widely in composition. Corrections for matrix effects based on a matrix of influence coefficients, the calculation of a mass absorption coefficient from major component data and Compton scatter methods are discussed; data are presented which demonstrate that all three procedures can be used with low dilution fusions. Spectral impurities (principally of Cu, Ni and Zn) which cause problems in some trace element analyses using low dilution fusions and may also affect pressed rock powder studies are investigated and a simplified correction procedure is proposed. Lower limits of detection, accuracy and precision for determinations of 20 elements, carried out using low dilution fusions, indicate that the low dilution fusion procedure is well suited to routine whole rock analyses of major and trace elements.
Single pass major element x‐ray fluorescence analysis of silicate rock samples using a Philips 1212 spectrometer
Authors: Parker R. J.
Published: May 2005

A ‘single pass’ method of analysing silicate rocks for their major element composition has been developed using a Philips 1212 x‐ray fluorescence spectrometer. Samples need only be submitted once to the spectrometer and all ten major elements (SiO2, TiO2, Al2O3, Fe2O3T, MnO, MgO, CaO, Na2O, K2O and P2O5) are determined using a Cr x‐ray tube and three analysing crystals, i.e. TIAP, PET and LiF220. The method has been evaluated in terms of the quality of the calibration lines for each element, the precision of replicated analyses and by the analysis of rock standards as unknown samples. The single pass method is rapid, facilitates on‐line data reduction and is capable of producing high quality analytical data.
A new procedure of powdered sample preparation by melting for x‐ray emission spectrometry
Authors: Novosel‐Radović Vj. , Maljković Da. , Dmitrović R.
Published: May 2005

A new procedure of powder sample preparation for x‐ray emission analysis by melting has been worked out in detail. The mixture sample‐flux was melted and cooled in graphite crucible. The resulting glass disk was ready for direct measurement. The re‐fused graphite electrode of an electric arc furnace was used as the material for the graphite crucible. The dimension and shape of the crucible bottom were determined on the basis of sample holder dimension and sample behaviour during the cooling step. The reproducibility of Kα line measurement was below 1%. Resistance of the crucible to handling and the influence of graphite on Fe Kα, Ca Kα, SKα, Si Kα and Mg Kα line intensities also were investigated.
Application of x‐ray microprobe technique to clay minerals: Vermiculite
Authors: Patel M.
Published: May 2005

The usual method of polishing the surface of a solid sample for examination using the x‐ray microprobe technique cannot be adopted for clay minerals. A modified method is suggested and its validity is tested using vermiculite mineral. It is observed that precision of quantitative elemental analysis increases significantly according to the present pretreatment procedure; variation from values obtained by wet chemical method is < 1% for SiO2, MgO and Fe2O3 and 2–3% for the rest. However, values obtained with the x‐ray microprobe technique vary enormously from point to point and this non‐uniformity is explained in terms of the structural characteristics of the clay mineral. The variation increases with the rise in temperature of treatment due to structural modifications occurring during heat treatment. The x‐ray microprobe technique has been found to be quite effective in determination of trace elements such as K and Ti.
A new source configuration for trace analysis of small samples by XRF
Authors: Shenberg C. , Boazi M. , Rapaport M. S.
Published: May 2005

A new geometry for a radioactive source was developed for the XRF determination of trace elements in the range 0.1–50 μg in samples with diameters from 2–5 mm. The new set‐up was constructed with five 241Am (45mCi each) point sources. The shielding and configuration of the source, as well as the choice of appropriate collimators in the optimal shapes and dimensions, were investigated in detail. The study was carried out to establish the conditions for obtaining maximum sensitivity. The count rates and signal‐to‐background ratios were compared with those obtained with an annular source and showed an improvement of a factor of ∼2 in the signal‐to‐background ratio and of a factor of 2–9 in the peak intensity for the elements studied (29≤ Z ≤ 47).
Determination of brass composition and plating thickness on brass‐plated wire and cord by x‐ray fluorescence spectrometry
Authors: Ponchon J. L. , Bourrain P. , Palsky A.
Published: May 2005

The control of brass composition and plating weight on brass‐plated steel wire and cord used as reinforcement in tyres is generally carried out by atomic absorption spectrometry, or by polarography. These methods require a mineralization of the sample and the analysis time is very long. On account of this, we have studied a direct analytical method on wires based on x‐ray fluorescence spectrometry. The mathematical method we use suppresses the influence of the cord construction and allows to calculate simultaneously the composition and thickness of the brass coating. The analytical performances, i.e. repeatability, accuracy and analysis time, are better than those prevailing with atomic absorption spectrometry or differential pulse polarography. Moreover, by dispensing with mineralization of the sample, XRFS is particularly well‐fitted for a routine control in production.
Fabrication and use of permanent monitors and standards
Authors: Forté Michel
Published: May 2005

Epoxy adhesive and aluminium powder have been used as binders to make permanent standards for x‐ray fluorescence and diffraction. These standards are easy and cheap to fabricate and are very durable. They can be used as internal standards or calibration standards. Three methods of fabrication are proposed and compared.
A study of mathematical models for XRF spectrometry analysis of copper mattes and slags
Authors: Budesinsky Bret W.
Published: May 2005

The Rasberry‐Heinrich method and its three modifications (delta method, expanded square intensity method and double constant method) together with the Tertian and a strictly empirical method were used for the analysis of copper mattes and slags. The expanded square intensity method, which represents a combination of theory and empiricism, gave the most accurate results.
A new method for matrix corrections by radioisotope excited x‐ray fluorescence
Authors: Hallak A. B. , Saleh N. S.
Published: May 2005

A method has been investigated which allows calculations of the absorption correction factors in the energy range 1.0–5.0 keV using 55Fe excitation source. From the experimentally‐measured absorption factors between 6.0 and 20.0 keV using 109Cd excitation source, the coefficients at lower energies with the associated absorption jumps are generated through an iterative procedure.
Surface density measurement of pure element thin films by radioisotope x‐ray fluorescence spectroscopy
Authors: Saleh N. S. , Hallak A. B.
Published: May 2005

A method for measuring the surface density of pure element thin films using x‐ray fluorescence and coherent scattering of primary radiation has been developed. The accuracy is greatly improved by intensity ratio measurements where the dependence on the accuracy of the fundamental parameters is eliminated.
A mobile installation for energy‐dispersive multi‐element x‐ray fluorescence analysis for application in the field
Authors: Hoffmann P. , Lieser K. H. , Hofmann T. , Sommer R.
Published: May 2005

The construction of a mobile XRF unit is described. It consists of a radionuclide source (109Cd), shielding, a sample exchanger for powdered samples, a semiconductor detector and an electronic measuring and evaluation system. The disadvantage of the supply of liquid nitrogen or liquid air for the semiconductor detector is avoided by use of a mobile unit for the production of liquid air constructed for this purpose. Numerous measurements were carried out at several location within the Federal Republic of Germany.
The stopping‐power correction in proton‐induced x‐ray emission analysis
Authors: Dyson N. A. , Fakhouri Miss H.
Published: May 2005

The thick‐target yield of characteristic x‐rays from a series of gold–silver binary alloys has been determined experimentally (relative to the yield from the pure elements) under proton bombardment, using proton energies of 1. 5, 2. 0 and 2. 5 MeV. The yield per unit concentration of gold or silver varies with alloy composition because of the progressively varying effects of proton stopping power (specific energy loss) and x‐ray self‐absorption in the target materials. Theoretical yields have been calculated using tabulated data for stopping power and x‐ray absorption. When both of these effects are taken into account, agreement with experiment is satisfactory. These results can be made the basis of stopping power and self‐absorption corrections in proton‐induced x‐ray emission analysis.
Fundamental algorithm between concentration and intensity in XRF analysis 1—theory
Authors: Rousseau Richard M.
Published: May 2005

A new formalism is proposed to correct with accuracy the matrix effects in x‐ray fluorescence (XRF) analysis. It has been deduced from Sherman's equations and includes a new algorithm between concentration and intensity, theoretically exact, and explicit expressions permitting the calculation of αij and ρij coefficients that correct for absorption and enhancement effects, respectively. In other words, the concept of correction coefficients is established on a solid theoretical basis. In the second part, it will be shown how to adapt this new formalism to practical situations. From an estimate of composition calculated by the Claisse–Quintin algorithm and an appropriate calibration, the new algorithm is used to refine the estimated composition for greater accuracy. This last approach is equivalent to the ‘fundamental parameters’ method but is presented in a simpler version adaptable to any mini‐computer.
Spectral intensity distributions from x‐ray tubes. Calculated versus experimental evaluations
Authors: Tertian R. , Broll N.
Published: May 2005

Apart from their general importance, an accurate definition of spectral intensity distributions from x‐ray tubes is required to support the development of mathematical matrix correction procedures for x‐ray fluorescence analysis. Since a direct measurement is costly, time consuming and occasionally difficult, and a purely theoretical approach is not suitable for current utilization, a simple, readily adaptable calculation procedure is very desirable. Concerning the continuum or white radiation from the x‐ray tube, such an evaluation was worked out by effecting (1) a modification to Kramers' law and (2) a refinement of the absorption correction regarding the absorption by the target itself. The new equation accounts very closely for the best known, carefully measured and corrected experimental distributions by Brown et al. and Loomis and Keith. Extended experiments are required to ensure systematization, and special steps are needed for the treatment of the characteristic radiation.
Study of some cobalt biomolecular complexes by x‐ray absorption spectroscopy
Authors: Chattopadhyay S. , Sapre V. B. , Mande C.
Published: May 2005

The fine structure in the vicinity of the K absorption edge of cobalt in some cobalt biomolecular complexes has been studied using a bent crystal x‐ray spectrograph of the Cauchois type. The average metal—ligand bond length in these complexes has been determined by applying Levy's theory.
Quantitative analysis of bulk samples without standards by using peak‐to‐background ratios
Authors: Heckel J. , Jugelt P.
Published: May 2005

A method is described for the quantitative analysis of bulk specimens without standards by using peak‐to‐local background ratios in energy‐dispersive electron probe microanalysis. Theoretical transport investigations have been used to derive an expression for the absolute determination of (P/B) ratios. Accurate measurement of the background below a peak is carried out without an exact knowledge of the surface geometry of the specimens. The advantages of this method are discussed in comparison with other correction procedures and the efficiency is demonstrated by means of quantitative analysis of nine binary specimens and two steel specimens.
Theoretical evalution of the efficiency of compton scattered radiation method in EDXRF analysis
Authors: Markowicz Andrzej
Published: May 2005

A theoretical evaluation of the efficiency of correction for the matrix absorption effect using Compton scattered x‐rays in EDXRF analysis has been carried out for thick samples and for monoenergetic primary radiation. The limitations of this correction method and the procedure for the selection of the optimum excitation energy are presented.
X‐ray fluorescence determination of light rare earth elements, Y and Th, by the fusion technique
Authors: Macháček V. , Weiss D.
Published: May 2005

A method for the determination of rare earth elements, Y and Th in raw materials with different matrices is described. The sample is fused with Li2B4O7 and Cr and Mo are added as internal standards. Single elements can be determined in a wide range of concentrations, viz. Ce, Nd, La and Pr from 0.02 to 25% and Sm, Gd, Y, Th and Eu from 0.005 to 1%. The use of the LiF (110) crystal and, possibly, chemical separation, reduces the coincidence of lines to a minimum. Mutual interaction between single elements is prevented by the application of empirical corrections.
Some experience in using the MECA‐10‐44 (XR‐500) x‐ray fluorescence analyser for solving geological problems
Authors: Margolin E. M. , Pronin Yu. I. , Choporov D. Ya. , Shil'nikov A. M. , Komyak N. I. , Goganov D. A. , Serebryakov A. S. , Fed'kov E. A.
Published: May 2005

The excitation conditions have been studied and the accuracy and sensitivity estimated of the MECA‐10‐44 energy‐dispersive x‐ray fluorescence spectrometer, in the determination of contents of 10 major and 25–30 rare and scattered elements in samples of rocks and ores. The use of the instrument for the rapid routine analysis of geological samples for separate groups of elements has been demonstrated; when carrying out combined geochemical investigations, such an instrument represents an essential link in the system of analytical methods applied for complete elemental composition analysis.
Depth profiling of brass by means of PIXE
Authors: Rössiger V. , Lenk M.
Published: May 2005

The PIXE (particle‐induced x‐ray emission) depth profiling technique was applied to brass coatings on steel wire. Applying protons with energies E0 = 100–360 keV from a small electrostatic accelerator, the surface region to a depth of up to about 1 μm can be investigated. Three, or at maximum four, parameters of a suitable model function for the concentration profile were evaluated by analysing the ratio of Cu Kα and Zn Kα experimental x‐ray yields as a function of the primary energy of the particles.
Analyses of barytes by x‐ray fluorescence spectrometry using a fusion method for sample preparation
Authors: Joslin D. , Salt P. D.
Published: May 2005

Variation in the composition of commercial sources of barytes (BaSO4) govern its suitability for use in the oilwell drilling industry to control the density of the circulating drilling fluid. A fusion method of sample preparation using GeO2 as a glass‐forming additive has been developed, enabling a 1 part sample to 4.1 parts ‘flux’ composition glass disc to be made for XRF analysis.
Analysis of powders by XRF using the smear technique
Authors: Purdue G. E. , Williams R. W.
Published: May 2005

A thin‐film technique has been developed for the quantitative analysis of grindable solids such as combustion chamber and spark‐plug deposits, coal and fuel‐oil ashes, sediments and catalysts. Only 20 mg of sample are required and results are virtually independent of the matrix for all elements of atomic number 11 (Na) and heavier.

Detection limits for the 25 elements so far calibrated range betweenf 0.05 and 1.0% by weight. The technique was proved using 22 certified materials, the precision being within 10% relative over much of the calibration ranges.
Least‐squares fits of fundamental parameters for quantitative x‐ray analysis as a function of Z (11 ≤ Z ≤ 83) and E (1 keV ≤ E ≤ 50 keV)
Authors: Poehn Christian , Wernisch Johann , Hanke Wolfgang
Published: May 2005

A presentation by useful approximations of fundamental parameters needed for XRF and EPMA is given. The set of fundamental parameters include: critical energy or edge energy, energy of characteristic x‐rays, edge‐jump, fluorescence yield, transition probability, mass absorption coefficient, backscatter coefficient, mean ionisation potential and atomic weight.
Statistical considerations in the overlap of powder diffraction patterns
Authors: Jaklevic Joseph M.
Published: May 2005

A simple model for the calculation of the probability of random overlap of partial powder diffraction patterns has been constructed. The application of the model to the analysis of complex mixtures is discussed.
Influence of sample thickness, excitation energy and geometry on particle size effects in XRF
Authors: Van Dyck P. , Markowicz A. , Van Grieken R.
Published: May 2005

Expressions are presented for calculating the matrix effect and the pure particle size effect in the XRF analysis of particulate samples with a discrete particle size. The equations are based on the absorption‐weighted radiometric diameter concept. Two excitation–detection geometries are considered, with the angles between the sample plane and both the incident and emerging radiation being either 90° (π geometry) or 45° (π/2 geometry). Calculations were made for different sample loadings and exciting radiation energies. The influence of these parameters on the matrix and pure particle size effects is shown. From the results, it is possible to predict the performances of alternative experimental correction procedures for the particle size effect, involving dual measurements at different excitation energies or in different excitation–detection geometries.
X‐ray analysis of nickel‐base alloys with theoretically derived inter‐element correction coefficients
Authors: Griffiths Joyce M. , Webster H. W. M.
Published: May 2005

Wide‐range calibrations for 16 elements in nickel‐base alloys have been established with theoretical inter‐element correction coefficients. Details of the instrument conditions and line‐overlap corrections are given. A new approach to the specification of the ‘average composition’ used for the calculation of correction coefficients is described. An accuracy superior to that obtained by currently used methods was achieved.
Dependence of the K X‐ray yield on target thickness in the S + Ge collision system
Authors: Bǎdicǎ T. , Ciortea C. , Popescu I.
Published: May 2005

Measurements of the target‐thickness dependence of the target K x‐ray production yields are reported for 1 and 2 MeV/amu Sq+ (q = 6 and 8) ions incident upon thin solid targets of Ge. Target K x‐ray production cross‐sections were extracted in the limit of vanishing target thickness. Comparisons of the data with theoretical estimates based on combinations of direct ionization and electron‐transfer processes are presented.