Interelement Effects Research Articles

Ensemble Combustion of Liquid Oxygen/ Gaseous Hydrogen Coaxial Flames

ABSTRACT Experiments were performed to investigate the ensemble combustion of a linear array of three coaxial liquid oxygen/gaseous hydrogen turbulent non-premixed jet flames. The experimental conditions were carefully controlled to duplicate those of a previous single element experiment as closely as possible, so that the single element flame could be closely compared with the present three element flame. All ensemble and inter-element effects were due to the turbulent combustion only; acoustic effects were intentionally suppressed. Abundant interactions were found both in the time averaged sense as well as in the dynamics of the larger scale motions. The multielement flames were found to be axially longer, and dominant frequencies were found to emerge for the multielement flames that were not present for the single element flames. A dynamic wave amplification mechanism previously identified for single element flames was found to remain present for multielement flames. However, the mechanism did not operate independently for each element in the ensemble, but instead entered into phase relationships with the neighboring elements. The phase relationship possibly encouraged the dynamics between jet flames that allowed the dominant frequencies to emerge. Several indications of such a phase relationship were found, but not all indications were observed to occur all of the time. It is possible that the coordination of the wave amplification mechanism between the flames was weak or intermittent. Other simultaneous processes probably also contributed to the overall flame behavior.

Insights into the inter-element effects in the EDXRF determination of zirconium in binary aqueous solutions via the calibration method

Calibration of the energy dispersive X-ray fluorescence (EDXRF) spectrometer, using pure elemental standard solutions of Cu, Zr, Nb, Mo, Ta, and U, was carried out and the instrumental sensitivity was derived for each. The effects of the presence of the rest of these elements on the calibration of Zr were evaluated by analyzing the respective binary solutions, separately. All the matrix elements led to a reduction in the Zr- sensitivity of the spectrometer. Intercepts of the calibration curves were found to decrease with Cu, Mo. Nb, Ta, and U led to the elevation of the intercepts. The highest specific changes (per mg of the matrix) in both the slope and intercept were observed upon the addition of Mo. Numerically, these values were -5,917 and -1,187 respectively. Limits of detection for Zr, from the calibration curve, were the best (0.28 μg) in the presence of 7.8 mg Mo and the worst (165.4 μg) in the presence of 53 mg U. The results were validated by multiple standard additions on a sample and analysis of reference standard solution of Zr. Quality control sample analysis re-affirmed the accuracy of the present results. Repeatability was also established for the measurements of solution samples.

X-Ray Fluorescence Analysis in Biology and Medicine

X-ray fluorescence analysis (XRF) is widely used when determining the concentrations of elements in various materials in biological research. Current review considers the achievements related to the features of the XRF method. X-ray fluorescence analysis in most cases is a non-destructive method that has proven its potential for measuring the concentrations of elements with a high atomic number Z in organs and tissues in vivo. The main areas of its application in biology and medicine are content determination of basic and toxic elements in plants, samples of bones, teeth, hairs, nails and tissues of vital organs, body fluids such as blood, serum, plasma, saliva, urine, etc. Usually, these studies are part of applied programs that include environmental and metabolic analyses of the population, including the influence of professional factors. The advantages of XRF are also discussed with regards to biological materials. It is noted that the form of the element in the sample practically does not affect the analysis result. In recent years, several new XRF spectrometers models have been designed, where polycapillary lenses and half lenses are used as collimating systems. This is important in the case of in vivo application of X-ray fluorescence determination of certain elements in bones and tissues. The dynamic development is typical for detectors with thermoelectric cooling. Variants of preparation of biological materials for analysis are discussed (grinding, dry or wet ashing, acid decomposition, use of suspensions in the case of XRF with TIR). The results of evaluating the interelement effects for XRF of materials of plant origin, including herbs, spices, apple leaves, birch and tomato leaves, tea, wheat, rye, rice, oatmeal, flax flour, beans, ground, and instant coffee are presented. Examples of the use of XRF in various types of forensic research are considered: poisoning, counterfeiting of drugs and food brands, dental implants, identification of remains. The review presents examples of the participation of Russian X-ray physicists in solving the problems under consideration. The list of references is 400 papers, mainly including the publications of the last 20 years.

Анализ металлических сплавов на эмиссионных спектрометрах с низким разрешением. Учет влияния "третьих" элементов

Анализ металлических сплавов на эмиссионных спектрометрах с низким разрешением. Учет влияния "третьих" элементов

Analysis of metal alloys on low-resolution emission spectrometers. Correction of inter-element effects

Analysis of metal alloys on low-resolution emission spectrometers. Correction of inter-element effects

The inter-element coupling effect of triangular flat shells

Purpose– The purpose of this paper is to study the inter-element coupling effect of membrane and plate components between two adjacent shells occurring on the common boundary.Design/methodology/approach– In this paper, three triangular flat shells developed by combining an excellent membrane element (OPT) with three outstanding plate bending elements (DKT, RDKTM and DST-BK), respectively, are used to study this phenomenon. Benchmark tests are implemented to evaluate the performance of three selected plate elements and the formulated flat shells.Findings– The inter-element coupling effect of membrane and plate components belonging, respectively, to two adjacent shells deteriorate the performance of shells. Therefore, a shell’s performance cannot be guaranteed certainly by the superimposed membrane and plate behaviors.Practical implications– The “order matching” criterion is proposed to explain this phenomenon and it is concluded that the flat shell that follows this criterion explicitly may alleviate or even overcome the inter-element coupling effect.Originality/value– Previous studies mainly focus on formulation of high-performance membrane and plate elements. However, the inter-element coupling effect of membrane and plate components between two adjacent shells occurring on the common boundary, has attracted less attention. Thorough benchmark tests for three flat shells are implemented to investigate the phenomenon. The results shows that the inter-element coupling effect deteriorates the performance of shells. And the “order matching” criterion is proposed to explain this phenomenon and it is concluded that the flat shell that follows this criterion explicitly may alleviate or even overcome the inter-element coupling effect.

Rapid and non-destructive determination of uranium and thorium by gamma spectrometry and a comparison with ICP-AES

A rapid, simple and non-destructive method was developed for the determination of thorium, uranium by gamma ray spectrometry (high purity Ge detector) in thorium–uranium mixture. Using the calibration curves, thorium and uranium were analyzed in synthetic samples with RSD ~2 %. Inter element effect suggested that 583 and 185.7 keV gamma lines are more suitable for the determination of Th and U, respectively in a mixture of Th–U. The newly developed method was validated by routinely employed method using synthetic samples. An ICP-AES based method was developed for the determination of uranium and thorium for comparison purpose.

Wavelength-dispersive X-ray Fluorescence Spectrometric Determination of Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th in Komatiites

Abstract Komatiites are mantle-derived ultramafic volcanic rocks. Komatiites have been discovered in several States of India, notably in Karnataka. Studies on the distribution of trace-elements in the komatiites of India are very few. This paper proposes a simple, accurate, precise, rapid, and non-destructive wavelength-dispersive x-ray fluorescence (WDXRF) spectrometric technique for determining Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th in komatiites, and discusses the accuracy, precision, limits of detection, x-ray spectral–line interferences, inter-element effects, speed, advantages, and limitations of the technique. The accuracy of the technique is excellent (within 3%) for Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Zr, Nb, Ba, Pb, and Th and very good (within 4%) for Y. The precision is also excellent (within 3%) for Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th. The limits of detection are: 1 ppm for Sc and V; 2 ppm for Cr, Co, and Ni; 3 ppm for Cu, Zn, Rb, and Sr; 4 ppm for Y and Zr; 6 ppm for Nb; 10 ppm for Ba; 13 ppm for Pb; and 14 ppm for Th. The time taken for determining Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th in a batch of 24 samples of komatiites, for a replication of four analyses per sample, by one operator, using a manual WDXRF spectrometer, is only 60 hours.

Interelement effects in X-ray fluorescence determination of the surface density of vanadium nanofilms on various substrates

This paper presents a detailed study of the effect of the fluorescence of bulk substrates on the fluorescence intensity of vanadium nanofilms of various thicknesses and examines vanadium Kα fluorescence enhancement by emission from the substrate. We calculate correction coefficients that take into account film-substrate interelement effects and demonstrate that it is appropriate to use unified auxiliary systems in analysis of real nanofilm structures.

能量色散X荧光分析中元素间效应的蒙特卡罗模拟

能量色散X荧光分析中元素间效应的蒙特卡罗模拟

Quantitative determination of sulfur by high-resolution graphite furnace molecular absorption spectrometry

In this paper a new procedure for quantitative determination of sulfur, which is based on the molecular absorption of tin sulfide at a wavelength of 271.578nm, is described. For that purpose a commercially available high-resolution continuum source atomic absorption spectrometer with a transversely heated graphite tube furnace is used. The temperature program is optimized and the measurements are accomplished with a Zr-coated graphite tube without platform.A limit of detection of 0.16ngS absolute is achieved. Furthermore, the accuracy of the procedure is verified by the recovery rate of both an inorganic and an organic compound. Several water samples from rivers and ponds, three mineral waters with a concentration range from 3 to 370mg/LS, and one certified reference material are analyzed, too. The results are consistent with the measured values of ion chromatography and gravimetric analysis. The non-spectral interelement effect of Ni has displayed a signal loss. With a 1:1 relation of metal to analyte a loss of 11% of the absorption signal has appeared. This effect is very seldom in natural environment, so the procedure is robust and there are no spectral interelement effects. In addition, this procedure is faster and more easy-to-handle than other methods at this point of time, and resulting in the improved limit of detection.

Development of a methodology for the determination of americium and thorium by ICP-AES and their inter-element effect

Due to the scarcity of good quality uranium resources, the growth of nuclear technology in India is dependent on the utilization of the vast thorium resources. Therefore, Advance Heavy Water Reactor is going to acquire significant role in the scenario of Indian nuclear technology, where (Th, Pu)O2 will be utilized as fuel in the outermost ring of the reactor core. This will lead to a complex matrix containing thorium as well as americium, which is formed due to β- decay of plutonium. The amount of americium is dependent on the burn up and the storage time of the Pu based fuels. In the present case, attempt was made to develop a method for the determination of americium as well as thorium by ICP-AES. Two emission lines of americium were identified and calibration curves were established for determination of americium. Though the detection limit of 283.236 nm line (5 ng mL−1) of americium was found to be better than that of 408.930 nm (11 ng mL−1), the former line is significantly interfered by large amount of thorium. Three analytical lines (i.e. 283.242, 283.730 and 401.913 nm) of thorium were identified and calibration curves were established along with their detection limits. It was observed that 283.242 and 401.913 nm line are having similar detection limits (18 and 13 ng mL−1, respectively) which are better than that of 283.730 nm (60 ng mL−1). This can be attributed to the high background of 283.273 nm channel of thorium. The spectral interference study revealed that even small amount of americium has significant contribution on 283.242 nm channel of thorium while the other two channels remain practically unaffected. Considering both these facts, spectral interference and analytical performance (detection limits and sensitivity), it was concluded that 401.913 nm line is the best analytical line out of the three lines for determination of thorium in presence of americium.

Chocolate and Cocoa Products as A Source of Essential Elements in Nutrition

In order to test current quality and nutritional merits of chocolate, 54 dark, plain and milk chocolate samples as well as cocoa were collected from the Austrian market and analyzed for many nutrient, essential and non essential elements, including the non-metals B, Si, S, and I. The cocoa contents ranged from 20-100%. Among the nonwanted trace elements, nickel was Gaussian distributed with a rather high mean of 4.9 mg/kg. Cd largely ranged below 0.20 mg/kg, but a few were higher, reaching 0.90 mg/kg. Contrary to previous studies, the same sample set was used to determine the contents of several element groups to look for interelement effects. Compared with element levels met in other sweets, element contents in chocolate were significantly higher. Many trace elements, like B-Co-Cr-Cu-Fe-Mn-Zn, ranged at levels met in green plants. Nickel concentrations were surprisingly high and about Gaussian distributed. Silicon was frequently higher than aluminium. Contaminants Pb, As, V, and Tl were very low, Cd was variable. Factor analysis grouped the element concentrations into B-Co-Cu-Mg-Mn-Ni- P-S-Zn, Al-Cr- Fe-Si, and Ca-J-Na, which might represent a component from the cocoa bean, its outer shell, and milk. Contrary to other sweets, consumption of 100 g of chocolate satisfies the recommended daily intake for Cr-Cu-Fe, and 300 g for Mg and Zn, which is particularly important for the adequate trace element supply of children and vegans.

Inter-element Effects in the Determination of Trace Amounts of Plutonium by High Resolution Inductively Coupled Plasma Atomic Emission Spectrometry

Inter-element Effects in the Determination of Trace Amounts of Plutonium by High Resolution Inductively Coupled Plasma Atomic Emission Spectrometry

Factors influencing the behavior of land applied biosolids

Using biosolids from the Hampton Roads Sanitation District (HRSD), laboratory studies were conducted to provide an insight into the behavior of this material when it is applied on land. The interaction and affinity of the biosolids for heavy metals was determined by packing reactor columns with known amounts of the biosolids and passing through the packed columns aliquots of several heavy metal solutions including, cobalt, copper, lead, iron, manganese, and zinc. The process was repeated until the retention capacity of the columns was reached. Solution parameters were varied to allow investigations of the influence of pH, ionic strength, and inter-elemental effects. The affinity of the biosolids for each metal was determined by calculating the mass of the metal that was adsorbed on the biosolids (removed from the solution) per gram of the biosolids. Using batch and reactor column procedures, samples of the biosolids were fractionated to determine water soluble, exchangeable, adsorbed, organically bound, carbonate, and sulfide fractions and to determine the lability, mobility, and availability of the heavy metal and other contaminants in those fractions. A fractional distribution extraction protocol was specifically conducted for the lead-biosolids complex to provide an insight into the lability and bioavailability of the biosolids-bound lead. The affinity of metal ions for the biosolids was found to increase in the order Pb>Fe>Cu>Zn>Ni>Mn>Co. Correspondingly, synergistic effects of the different metals led to characteristic decreases in the respective binding capacities. A decease in system pH led to a decrease in the binding capacity, a trend that was also observed when the ionic strength increased. Using lead as a model, fractionation studies revealed that adsorption of lead by biosolids is mainly associated with the carbonate fraction.

Chemofiltration of eriochrome black T-zinc complex and determination by X-ray spectrometry

In the present work, a new methodology for zinc preconcentration and separation and its determination by X-ray spectrometry is proposed. The methodology is based on the formation of a complex using Eriochrome black T (1-naphtalensulfonic acid, 3-hidroxy-4-((1-hidroxy-2-naphtalenyl)azo)-7-nitro, monosodium salt), EBT, as complexing agent. Next, the complex is retained on a polyamide membrane by a chemofiltration process. The chemofiltrated material on the membrane constitutes a thin film, which minimizes or eliminates the interelemental effects when the instrumental detection is realized by X-ray fluorescence spectrometry. As the preconcentration method presented is based on the formation of a complex which will interact with the membrane during the chemofiltration, it was necessary first to establish the optimal conditions for the complex formation of Zn-EBT in aqueous medium and then to explore the optimal conditions for obtaining the thin film. The pH dependence of the metal ion chemofiltration on the membrane and other variables, such as contact time and retention capacity of the membrane, were also optimized. Chemofiltration step provided an enrichment factor of 30,000, improving considerably the instrumental detection limit, allowing the determination of trace zinc in environmental samples.

Approaches to improving the accuracy in X-ray fluorescence analysis of Si1 − x Ge x films

This work examines approaches to improving the accuracy in the X-ray fluorescence determination of the composition and thickness of thin Si1 − xGex films on Polikor alumina substrates. We calculate correction coefficients that take into account the interelement effects in the films and demonstrate the possibility of reaching the required accuracy level in determining film composition and thickness. The results are used to optimize conditions for the preparation of films with tailored electrical properties.

Linear programming from generalised scattering matrix analysis of array for minimum sidelobe level and prescribed nulls

A pattern synthesis technique for arbitrary planar arrays which are characterised in terms of a generalised scattering matrix and whose radiated field is expressed as a spherical mode expansion is introduced. The procedure yields the complex-valued excitations to achieve a minimum-maximum sidelobe level given a specified pointing direction and mainlobe width, as well as prescribed field nulls. All inter-element coupling effects coming from complex radiating structures used as array elements are inherently taken into account. Numerical results are presented for arrays of dielectric resonator antennas.

Application of the background standard method for the determination of Rb, Sr, Y, Zr, and Nb contents in phosphorites by x‐ray fluorescence

AbstractThe aim of the present work is to demonstrate the application of the x‐ray fluorescence (XRF) technique to the determination of Rb, Sr, Y, Zr, and Nb contents in phosphorites. The effect of a chemical sample composition on fluorescence intensities of analytical lines has been taken into account using the background standard method.A novelty of the work is the detailed study of a background to choose the background position, free from the spectral line overlaps of the elements presented in the sample. The most suitable background position is the position at the angle 2θ = 29° when using the analyzing crystal LiF(200). During our investigation we faced a problem of choice of Certified Reference Materials (CRMs) for the calibration of the phosphorites. To estimate interelement effects and to choose CRMs for the calibration the intensities were theoretically calculated. The statistical processing of analytical results of the technique is carried out. This technique may be applied to the determination of Rb, Sr, Y, Zr, and Nb contents in the phosphorites. Also, the possibility has been demonstrated to use the XRF technique for geochemical investigations of rocks. Phosphorites of Bokson‐Khubsugul Basin were selected as an example. As a result of the investigation the genetic type of phosphorites was established, which corresponded to the present geodynamical depositional environment. The character of the distribution of Rb, Sr, Y, Zr, and Nb contents in the phosphorites was also studied. Copyright © 2008 John Wiley & Sons, Ltd.

Computer-guided alignment I : Phase and amplitude modulation of alignment-influenced optical wavefront

As the first part of a development programme on computer-guided alignment (CGA), we model the alignment influence on the optical wavefront in terms of the phase and amplitude modulation. This modulation is derived from the interaction between alignment parameters and influence functions, both expressed in complex form. The alignment influence model is used to approximate the ray-traced target wavefront of a randomly mis-aligned multi-element system. The approximated wavefront shows a factor of ~ 100 improvement in predicting the target, when coupled non-linear influences among elements are included. This demonstrates the significance of the inter-element effect. We discuss the possibility of adopting the model for rectifying mis-alignment of multi-element systems.