Wavelength Dispersive X-ray Fluorescence Research Articles

Evaluation of Physico-Chemical Characteristics of Cement Superplasticizer Based on Polymelamine Sulphonate.

Cementitious materials are used to construct an engineered barrier in repositories for radioactive waste. The cement matrix may contain a variety of organic compounds, some of which are polymeric admixtures used as plasticizers. Superplasticizers (SPs) are highly effective organic cement additives for reducing water amount, increasing workability, homogeneity, plasticity and the non-segregation of mortars and grouts, improving mechanical properties and resistance to destructive environments. SPs in cement could have an impact on the long-term safety of the disposals of radioactive waste. These organic agents can leach from the cementitious matrix into groundwater and may affect the migration behaviour of radionuclides. The detailed chemical composition and other characteristics of the cement (CEM I 42.5 R, Sweden) used for the leaching experiments were evaluated. It contained mainly CaO (52.51 ± 1.37, %), and the surface area of the cement particles was 13.2 ± 1.3 m2/g. An insignificant increase in pH (from 12.6 ± 0.1 to 12.8 ± 0.1) was observed for the leachates over 10 days. A commercially available cement superplasticizer based on polymelamine sulphonate (PMS) Peramin SMF10 (Peramin AB, Sweden) was chosen for the research. The product's chemical composition was analysed using wavelength-dispersive X-ray fluorescence (WD-XRF) spectroscopy, while other physico-chemical properties of the PMS superplasticizer were assessed by Raman spectroscopy and thermo-gravimetric analysis. In aqueous solutions and powders of PMS, the same most intensive features were observed at 774 cm-1 (ring out-of-plane deformation), 977 cm-1 (C-N-C bending, SO stretching) and 1055 cm-1 (C-N=C bending) in the Raman spectra. At up to 270 °C, the polymer was thermally stable. Raman and UV/Vis spectroscopies were used to assess the rate of the alkaline degradation of PMS superplasticizer in different aqueous solutions. No changes were observed in the hydrolytic solutions with any of the above analytical methods over a period of 3 years. The results obtained revealed a good thermal and chemical stability (in highly alkaline media, pH = 9.9-12.9) of the PMS polymer.

A new approach for sample preparation to determine the multi-element composition of cobalt-rich crust samples by wavelength dispersive X-ray fluorescence spectrometry

A new approach for sample preparation to determine the multi-element composition of cobalt-rich crust samples by wavelength dispersive X-ray fluorescence spectrometry

Structural and morphological evolution of biogenic hydroxyapatite: Effects of heating and cooling treatment

Despite extensive research, many aspects of biogenic hydroxyapatite (BHA) structural changes during heating remain unresolved. This work aims to understand how heating and cooling affect the growth of BHA crystallites obtained from porcine bone through an in-situ study. Wavelength-dispersive X-ray fluorescence of BHA has revealed the presence of trace elements such as Si, Al, Fe, Mg, and K. These elements serve as substitutional defects within the BHA structure. Vibrational analysis using infrared spectroscopy helped to verify the removal of the organic phase by combustion. In situ high-temperature X-ray diffraction and Rietveld refinement were used to analyze the changes in BHA crystallite size, lattice parameters, and microstrain. High-resolution micrographics confirmed the simulation of crystal habit using family planes (002), (111), (100), and (110) and validated the removal of organic material. Remarkably, the crystallite size increased dramatically after organic debris removal and coalescence events, while it remained constant before coalescence temperature.

Ionomic analysis of Prosopis laevigata response to heavy metals: phytoremediation potential determined by wavelength-dispersive X-ray fluorescence

Prosopis laevigata (mesquite) plants can tolerate drought, thermal stress, alkalinity, salinity, and toxicity of heavy metals, making them attractive for phytoremediation. Nonetheless, most of these features have been studied under controlled laboratory conditions. In this work, the bioaccumulation of heavy metals in a free-living population of P. laevigata trees growing in a heavily metal-contaminated site (aluminum, chromium, iron, titanium, copper, and zinc) was analyzed. Furthermore, crystal phases of mineral nutrients and trace elements found in P. laevigata tissues were determined by X-ray diffraction. P. laevigata trees accumulated 705 (± 17), 47,064 (± 1459), 14,800 (± 401) and 30,000 (± 1719) mg/kg of Cu, Zn, Fe and Al, confirming the potential of these plants to hyper-accumulate metals. The X-ray diffraction analysis showed that P. laevigata trees can chelate Al3+ with phosphates to form orthorhombic crystals of aluminum phosphate (AlPO4) in the tissues. This aluminum chelation was probably a mechanism of tolerance used by the plant. The inoculation of seedlings with the endophytic Bacillus cereus MH778713 did not prevent Cr-accumulation in the plant but increased metal tolerance and seedling development. These results highlight the use of P. laevigata and B. cereus MH778713 together as tools for heavy metal bioremediation, particularly on arid and semiarid soils.

Microwave-Assisted Hydrothermal Synthesis of Pure-Phase Sodalite (>99 wt.%) in Suspension: Methodology Design and Verification.

Despite numerous studies focused on the hydrothermal (HT) synthesis of fly ash zeolites (FAZs), this method still has many limitations, the main of which is the low yield of zeolites. Hydrothermally synthesized zeolites are typically multiphase and exhibit low purity, which limits their applicability. Pure-phase zeolites have been primarily prepared from filtrates after alkaline mineralization of fly ashes, not directly in suspension. In addition, the published methodologies have not been tested in a wider set of samples, and thus their reproducibility is not confirmed. The aim of the study is to propose a reproducible methodology that overcomes the mentioned limitations. The influence of the Si/Al ratio (1.3:1-1:2), the type and concentration of the activator (2/4 M NaOH/KOH/LiOH), the reagent (30% LiCl), the duration (24-168 h), and the temperature (50-180 °C) of the synthesis phases were studied. The sequence of the synthesis phases was also optimized, depending on the type of heat transfer. The fly ashes were analyzed by wavelength-dispersive X-ray fluorescence (WD XRF), flame atomic absorption spectrometry (F-AAS), and X-ray diffraction (XRD). The energy intensity of the synthesis was reduced through the application of unique microwave digestion technology. Both microwave and combined (microwave and convection) syntheses were conducted. FAZs were identified and quantified by XRD analysis. This study presents a three-stage (TS) hydrothermal synthesis of pure-phase sodalite in suspension. Sodalite (>99 wt.%) was prepared from nine fly ashes under the following conditions: I. microwave phase: 120 °C, 150 min, solid-to-liquid ratio (S/L) 1:5, Si/Al ratio 1:1.5, and 4 M NaOH; II. convection phase: 120 °C, 24 h, S/L 1:40, and the addition of 30 mL of 30% LiCl; and III. crystallization: 70 °C for 24 h. The formation of rhombododecahedral sodalite crystals was confirmed by scanning electron microscope (SEM) images.

A review of laboratory, commercially available, and facility based wavelength dispersive X-ray fluorescence spectrometers

Wavelength dispersive X-ray fluorescence (WD-XRF) spectroscopy is a widely used instrumental spectroscopy method for a variety of samples.

Interface smoothing in short-period W/B4C multilayers using neon ion beam polishing

Short-period 2.5 nm W/B4C multilayers are useful as dispersive Bragg reflectors in wavelength-dispersive x-ray fluorescence. However, high roughness at the W–B4C interfaces deteriorates optical performance. To improve this, low-energy neon ion beam polishing (IBP) has been applied in sputter-deposited 2.5 nm W/B4C multilayers. Two energies, 200 and 50 eV, were investigated to study the effects of polishing by sputter removal (200 eV) and polishing by the mobilization of weakly bound surface atoms (50 eV). Atomic force microscopy and x-ray scattering showed reduced interface roughness for both IBP energies. However, the optical constant profile of 200 eV IBP showed strong W–B4C intermixing and interface asymmetry, leading to significant reflectance loss. In contrast, 50 eV IBP resulted in sharp, symmetric interfaces and increased optical contrast. A 43% peak reflectance at θ = ⁓9.7° grazing for W/B4C with 50 eV IBP was measured at λ = 0.834 nm—a 6.4% increase relative to non-polished W/B4C, corresponding to a 25% increase in integrated reflectance. These results highlight the necessity of using low-energy ion polishing by the mobilization of weakly bound surface atoms in short-period multilayers—rather than polishing by sputter removal.

Atomic Layer Deposition of HfAlOx for High-k Gate Dielectrics

Nowadays, the downscaling of CMOS devices requires continued effort to propose high performance components with extremely compact size. Surely, this trend is not achievable without extremely enhanced High-k gate stack materials, inter alia. For years, HfO2-based dielectrics deposited using ALD (Atomic Layer Deposition) technique are perfect dielectrics of choice for various devices and applications (Memristor, resistive random access memory, ferroelectric random access memory, antiferrolectric capacitances, ferroelectric FET...).As such, HfAlOx films present a good compromise between HfO2 and Al2O3 in term of coupling properties and insulating capabilities in comparison with both single HfO2 and Al2O3 films. The purpose of this work is to evaluate binary high-k HfAlOx dielectrics deposited by ALD technique. ALD is well suited for deposition of ultrathin films with exceptional capabilities enabling precise thickness, stoichiometry control and conformal growth at atomic scale. In this work, we focused on Al2O3/HfO2 films fabricated using two approaches: (i) repeatedly alternating the deposition of two different and separate extremely thin oxides (Al2O3 and HfO2; particular focus on HfO2/Al2O3/HfO2/Al2O3/HfO2 multilayer stack with equivalent Al fraction around 30%); (ii) combination of ALD super cycles allowing the formation HfAlOx layers. We analyze the general performance and the behavior of the binary high-k HfAlOx dielectrics (10 nm thin layers deposited at 300°C using TiCl4-TMA-H2O precursors) using physico-chemical (X-ray photoelectron spectroscopy XPS, X-ray reflectometry XRR, wavelength dispersive X-ray fluorescence WDXRF) and electrical measurements (Hg probe measurements, MIM capacitance).The incorporation of Al2O3 in the composition of the HfO2 gate dielectrics allows a perfect monitoring of physico-chemical properties varying from HfO2 layers to Al2O3 layers by controlling the number of Al2O3 and HfO2 ALD cycles. In this respect, we were able to monitor the Al fraction in the range of 5% to ~86% in the mixed binary dielectrics (Figure 1: XRR density of mixed binary layers vs Al/[Al+Hf] ratio, Figure 2: Al and Hf fractions in the mixed layer determined by WDXRF and XPS analysis).The electrical characteristics of the HfAlOx dielectrics confirm the influence of the Al fraction in the HfO2 layer. The leakage currents of the mixed layers decreases with increasing the Al fraction (Figure 3: J/E characteristics of mixed and stacked HfAlOx layers). The breakdown voltages for all mixed HfAlOx layers are greater than that of reference HfO2 layer. On the other hand, the shown multilayer presents an intermediate leakage currents profiles between the two mixed HfAlOx (25%Al and 40%Al). Thus, the incorporation of Al in the construction of HfAlOx system is likely to decrease the number of defects. Furthermore, the fully integrated MIM structures exhibit areal capacitance in the range 10-15 nF/mm2 of ALD-based high-k HfAlOx (10 to 12 nm) depending on the Al fraction. Thus, ALD-HfAlOx with various composition highlight the potential tremendous for high-κ capacitances stack for CMOS semiconductor devices. Figure 1

Photodegradation of Methylene Blue and Crystal Violet by Zr-Modified Engelhard Titanium Silicate 10

The present work focuses on the removal of dyes from polluted water, and, more precisely, the targets are crystal violet (CV) and methylene blue (MB). For this purpose, a series of Zr-modified catalysts based on microporous Engelhard Titanium Silicate 10 (ETS-10) were developed and synthesized. Aiming at improvement in the photodegradation efficiency and stability of ETS-10, Zr centers replacing part of Ti ones were introduced during the synthesis procedure. The obtained Na-K-ETS-10/xZr catalysts were characterized by X-ray powder diffraction (XRD), wavelength dispersive X-ray fluorescence (WDXRF), N2 physisorption and Fourier transform infrared spectroscopy (FTIR). The photocatalytic properties of Na-K-ETS-10/xZr- (x = 5, 10, 15 and 20 wt% Zr) catalysts were studied in terms of water purification from crystal violet and methylene blue. The Na-K-ETS-10/xZr wt% x = 6 catalyst appeared to be the most efficient in the photodegradation of CV and MB, removing nearly 100% of the dyes. Kinetic studies showed that the removal of CV and MB is a rapid process and one, which obeys the non-linear pseudo-second-order model.

The selection of an appropriate concrete mixture for casting a pile cap in hot weather using 3D finite element model

In this study, the finite element model (FEM) was developed to select an appropriate concrete mixture for a large heavily reinforced bridge pile cap located in Qassim region of Saudi Arabia. The pile cap with dimensions of 9 m x 9 m in plan and 1.8 m in depth was exposed to hot weather conditions in summer season. The heat of hydration in mass concrete results in high temperature gradients across the depth of the concrete creating excessive thermal stresses resulting in micro-cracking at the surface. The concrete mixtures with 30% date kernels ash, 30% fly ash, 30% natural pozzolan, 30% limestone powder, 30% ground granulated slag and 60% ground granulated slag were investigated. The experimental investigations were conducted on the concrete mixtures to determine the mechanical properties, such as tensile and compressive strength, thermal properties, such as thermal conductivity, specific heat, and thermal resistivity, and heat of hydration. The chemical compositions of ordinary Portland cement, date kernels ash, fly ash, natural pozzolan, limestone powder and ground granulated slag were analyzed using wavelength dispersive X-ray fluorescence (WDXRF). Based on the experimental and finite element model results, the concrete mixtures with 30% fly ash (FA), 30% ground granulated blast furnace slag (GGBFS), and 60% GGBFS were found to be less prone to cracking. Notably, the mixture with 60% GGBFS demonstrated the lowest likelihood of cracking, leading to its selection for casting the pile cap.

Substrates with Different Magnetic Properties Versus Iron-Nickel Film Electrodeposition

Abstract The hereby work presents the iron-nickel alloys electroplated on the different metallic substrates (aluminium, silver, brass) using galvanostatic deposition, with and without presence of the external magnetic field (EMF). The films were obtained in the same electrochemical bath composition - mixture of iron and nickel sulphates (without presence of additives) in the molar ratio of 2 : 1 (Ni : Fe), the electric current density (50.0 mA/cm2), and the time (3600 s). The mutual alignment of the electric (E) and magnetic field (B) was changeable - parallel and perpendicular. The source of EMF was a set of two permanent magnets (magnetic field strength ranged from 80 mT to 400 mT). It was analysed the surface microstructure, composition, morphology, thickness and the mechanical properties (roughness, work of adhesion). The surface morphology and the thickness of films were observed by Scanning Electron Microscopy (SEM) and Confocal Laser Scanning Microscopy (CLSM). The elemental composition of all FeNi films was measured using Wavelength Dispersive X-Ray Fluorescence (WDXRF). The crystalographic analysis of the deposits was carried out by X-Ray Diffraction. Depending on the used substrate, modified external magnetic field orientation influenced the tribological and physio-chemical properties of the deposited layers. The diamagnetic substrates and EMF application reduced the FeNi thickness and the average crystallites size, in contrast to the paramagnetic substrate. Parallel EMF increased the value of the tribological parameters for CuZn and Ag but decreased for Al. The content of FeNi structure was rising in the case of diamagnetic substrate and the dependence was opposite on the paramagnetic substrate.

Elemental analysis and quantification method development & validation of stigmasterol in Malaxis acuminata-A vanishing orchid

Orchids are highly valued for their therapeutic properties. Malaxis acuminata (vernacular name: Jeevak), is a vanishing orchid that has mystical healing potential. Wavelength dispersive X-ray fluorescence (WD-XRF) spectroscopy was employed to conduct elemental analysis of this orchid plant. Elements Potassium (K), Calcium (Ca), Phosphorus (P), Magnesium (Mg), Silicon (Si), Sulphur (S), Chlorine (Cl), Aluminium (Al), Iron (Fe), Ruthenium (Ru), Manganese (Mn), Zinc (Zn), Rubidium (Rb), Titanium (Ti), Copper (Cu), Strontium (Sr), and Nickel (Ni) are documented quantitatively and qualitatively. These elements are pivotal in shaping the plant's medicinal potential. Likewise, a multitude of organic molecules within the plant exhibit therapeutic potential. Stigmasterol is one such molecule, esteemed for its remarkable properties and a spectrum of health benefits. The present investigation additionally encompassed the establishment and validation of a methodology for the precise quantification of stigmasterol within the petroleum ether extract, utilizing high-performance thin-layer chromatography (HPTLC). The bioactive compound was isolated through the utilization of a specific mobile phase of toluene: ethyl acetate: methanol (8:1.5:0.5, v/v/v), and an optimal wavelength of 580 nanometers was ascertained. Validation of this method was conducted by the guidelines established by the International Council for Harmonisation (ICH). The calibration range for the stigmasterol was established to span from 400 to 3600 micrograms per spot (μg/spot). The Rf (retention factor) value for the separation of stigmasterol was determined to be 0.56 ± 0.04. The limit of detection (LOD) and limit of quantification (LOQ) were established at 15.954 nanograms per spot (ng/spot) and 48.344 ng/spot, respectively. Linearity (r2 0.999), accuracy (98.14– 99.21 %), and RSD of precision (1.953–2.984). specificity and robustness were evaluated by ICH guidelines. The stigmasterol content was 634.6 ± 3.28 μg/ml, which demonstrates promising results. This method exhibits substantial applicability in pharmaceuticals, nutraceuticals, food, and health-related sectors.

X-ray Fluorescence Analysis of Waste Sm-Co Magnets: A Rational Approach

Determination of the chemical composition of waste Sm-Co magnets is required for their efficient recycling. The non-stereotypical composition of said magnets makes an analysis extremely challenging. X-ray fluorescence spectrometry is a promising analytical tool for this task. It offers high accuracy and simplicity of sample preparation as it does not require sample dissolution. However, a serious limitation of X-ray fluorescence analysis is the spectral interference of matrix elements and impurities. In this work, a two-stage technique has been developed for the determination of the main components (Sm, Co) and impurities (Fe, Cu, Zr, Hf, Ti, Ni, Mn, Cr) in samples of spent samarium–cobalt magnets using wavelength dispersive X-ray fluorescence spectrometry. In order to overcome the main limitation of the chosen method and to maximize its capabilities of qualitative and quantitative analysis, we propose an approach to the selection of analytical lines and experimental conditions, as well as a preparation method for the calibration standards. The obtained results have been shown to have a good correlation with ICP-OES. The limits of detection are in the range of 0.001–0.02 wt%, and the limits of quantification are 0.003–0.08 wt%.

The complex of tannic acid and cetylpyridinium chloride: An antibacterial and stain-removal cleaner for aligners

Effective aligner hygiene is recognized as an important part of orthodontic treatments and oral hygiene. However, there is no effective cleansing method for removable aligners. In this study, we incorporated tannic acid (TA) with cetylpyridinium chloride (CPC) to develop the TA-CPC complex. The antibacterial properties of 15.8 mg/mL TA-CPC against Escherichia coli and Staphylococcus aureus were evaluated invitro, which were compared with 5.1 mg/mL TA, 10.7 mg/mL CPC, a commercial denture cleansing solution (YA; 15 mg/mL), and water. As for the assessment of stain-removal ability, the aligners stained by coffee were soaked in cleansing solutions, and the color changes (ΔE∗) were calculated on the basis of the CIE L∗a∗b∗ color system, and the National Bureau of Standards system was used for the clinical interpretation of the color change. Atomic force microscope examination, tensile property assessment, and wavelength dispersive x-ray fluorescence analysis were performed to investigate the material compatibility of TA-CPC, and Cell Counting Kit-8 assay and live/dead assay were used to test the cytotoxicity of TA-CPC. The results showed that TA-CPC had a positive zeta-potential, and cation-π interaction changed the chemical environments of the phenyl group in TA-CPC, resulting in greater inhibition zones of S. aureus and E. coli than other cleaners. The quantification of the biofilm biomass and the fluorescent intensities also reflected that the TA-CPC solution exhibited better antibacterial ability. As for the ability of stain removal, ΔE∗ value of group TA-CPC was 2.84 ± 0.55, whereas those of stained aligners immersed with deionized distilled water, TA, YA, and CPC were 10.26 ± 0.04, 9.54 ± 0.24, 5.93 ± 0.36, and 4.69 ± 0.35, respectively. The visual inspection and National Bureau of Standards ratings also showed that the color of stained aligners cleansed by TA-CPC was much lighter than those of the other groups. Meanwhile, TA-CPC had good compatibility with the aligner material and cells. TA-CPC is a promising strategy to inhibit the formation of biofilms and remove the stains on the aligners safely, which may disinfect the aligners to improve oral health and help keep the transparent appearances of aligners without impacting the morphology and mechanical properties.

Growth and optical performance of short-period W/Al and polished W/Si/Al/Si multilayers

Short-period multilayer mirrors are used in wavelength-dispersive x-ray fluorescence to reflect and disperse elements in the O-Kα– Al-Kα range. In this work, we investigated sputter-deposited 2.5 nm W/Al with 20 periods. Our results show that W/Al is a poor reflector due to a combination of high interfacial roughness and strong W–Al intermixing. To address this, we introduced 0.5 nm Si seed layers at the W-on-Al and Al-on-W interfaces each consecutive period, while reducing the Al thickness from ∼2.0 to ∼1.0 nm. The Si seed layers significantly reduced interfacial roughness and W–Al intermixing, which led to an increase in the reflectance of the first Bragg peak at λ = 0.154 nm. To further reduce interfacial roughness, ion beam polishing of the top Si layer was applied at each period. The resulting structure of W/Si/Al/Si with ion beam polishing showed that the reflection coefficient of the first Bragg peak at λ = 0.154 nm was comparable to that of standard W/Si. These findings demonstrate the effectiveness of seed layers combined with polishing techniques in synthesizing smooth, high-reflectance multilayers containing two materials that are otherwise challenging to synthesize.

One Pot Synthesis of Calcium Sulfate Hemihydrate from Fishbone-derived Carbon

Calcium Sulfate Hemihydrate (CSH) with uniform morphology and high crystallinity were successfully prepared by a precipitation-hydrolysis method in a concentrated sulfuric acid solution containing fishbone-derived carbon. The CSH was produced by carbonization of fishbone powder at 500 °C for 2 h, followed by sulfonation with concentrated sulfuric acid for 3 h. The solid mixture was washed until the pH of 2, then left at room temperature for 3 days. Physical properties of synthesized CSH were characterized using Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), wavelength dispersive X-ray fluorescence (WDXRF), Scanning Electron Microscope (SEM), nitrogen adsorption-desorption isotherm, and melting point test. It is concluded that the CSH were formed due to hydrolysis of fishbone-derived carbon in a moderately concentrated sulfuric acid solution of carbon-derived fishbone and crystallization into a fibrous octa calcium phosphate (OCP) form. In this research, effect of crystal growth time, effect of pH during the crystal growth, and effect of volume of the solution were also investigated. Copyright © 2023 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0). 

In vitro techniques for evaluating smear layer removal by root canal irrigants: a literature review.

Introduction: The purpose of this review is to address the most commonly used techniques for evaluating smear layer removal ability or chelating capacity of root canal irrigants, including Energy Dispersive X-Ray Spectroscopy (EDS or EDX), Atomic Absorption Flame Spectrometry (AASF), wavelength dispersive X-ray fluorescence spectrometry (WDXRF), inductive coupled plasma emission spectroscopy (ICP-AES), Scanning Electron Microscopy (SEM), and Fourier Transform Infrared Spectroscopy (FTIR).
 Methods: An electronic literature search was conducted in the Pub Med / MEDLINE database of indexed journals from 1992 to 2020. The search terms included chelating, chelation, calcium chelation, smear layer, smear layer removal, and demineralizing effect. 
 Results: All the techniques were classified in terms of their results, both quantitatively and qualitatively. Even though smear layer removal and chelating capacity are not the same parameters, most of the studies included both techniques to correlate their results. SEM is the most commonly used technique for evaluating smear layer removal using various root canal irrigants. Ethylenediaminetetraacetic acid (EDTA) (17%) was the most widely studied root canal irrigant. 
 Conclusion: Different techniques can be used to evaluate smear layer removal and chelating capacity of root canal irrigants. All of these methods have their corresponding advantages and disadvantages. This study aimed to provide researchers with a background for the selection of technique(s) to study the irrigant´s capacity for calcium chelation, which is applicable to smear layer removal

Earthen Architecture and Craft Practices of Early Iron Age Ramparts: Geoarchaeological Analysis of Villares de la Encarnación, South-Eastern Iberia

Abstract The use of mudbricks in Early Iron Age ramparts is an uneven feature of defensive architecture on the Iberian Peninsula. The use of mudbricks as a building material has been linked to the arrival of Levantine building traditions with the Phoenicians, and its appearance among local societies varies between the eighth and sixth centuries BC according to the public or domestic nature of the structures. In this article, we present the geoarchaeological analyses of the mudbricks used in constructing one of the defensive towers or bastions at Villares de la Encarnación (Caravaca de la Cruz, Spain). This site, endowed with two complex fortification lines and towers, is one of the main settlements for understanding the development of the Early Iron Age among the inland and mountain communities of the region. The analytical program includes wavelength dispersive X-ray fluorescence, CHN elemental analysis, and thin-section petrography and provides new data about soil procurement and manufacturing choices. These results highlight the technical and social complexity behind mudbrick constructions and the adoption of new earthen practices among Early Iron Age communities in order to build more imposing and elevated towers that might convey an image of the power and strength of these inland settlements.

Quantification of toxic metals in cropland soil using X-ray fluorescence

We aimed to assess toxic heavy metals in soil samples from cropland in Weenen (KwaZulu-Natal, South Africa) using X-ray fluorescence (XRF) spectroscopy. The metal contents in the soil samples were detected and quantified by wavelength dispersive XRF (WD-XRF) spectroscopy. On average, the values of all elements (mg/kg) were: Al (91.4 ± 6.9), Ba (0.488), Ca (16.8 ± 5), Fe (39.3 ± 0.8), K (15.7 ± 0.04), Mg (10.1 ± 0.3), Mn (0.6), Na (8.0 ± 1), P (1.3 ± 0.4), Si (458 ± 8) and Ti (5.6 ± 0.3). Toxic metals such as Hg, Cd, As, Pb, and Cr were not detected in the soil samples. The macronutrient P, which is capable of causing eutrophication in water bodies, was present at a low level in soil samples. The metal contents in both control and field samples were comparable, suggesting that the metals were mostly of lithogenic origin and not entirely influenced by anthropogenic activities. The metal levels we detected were within the limits reported to be safe by other studies. Significance: Although they are within the detection range, the toxic heavy metals mercury, cadmium, arsenic, lead and chromium, which enter the environment through the use of fertilisers on agricultural land, were not detected in this WDXRF spectrometry analysis. The remaining elements detected are lithogenic and non-anthropogenic, as the field and control samples had comparable concentrations. Nitrogen was not quantified, but phosphorus was present in a low concentration, so the field water run-off into the water bodies need not directly lead to water pollution in the area studied.

Mapping copper concentrations in tropical open cast mining fronts from X-ray fluorescence and FAAS techniques: A comparative study

Determining copper (Cu) contents and their spatial distribution in tropical open cast mining fronts is crucial for short-term exploitation planning. However, this evaluation in a fast and accurate way can be directly impaired by methods applied. The aim of this work was to assess the analytical performance of portable X-Ray fluorescence (pXRF) for Cu analysis in the mining fronts at the Cu Sossego Mine, in the Carajás Mineral Province, State of Pará, Brazil. For this, 143 drilling samples were collected in mining fronts at the Sequeirinho pit, an area chosen as representative of the heterogeneity of the Cu levels in the deposit of Sossego Mine. The samples were analyzed with three different techniques to determine the Cu levels as follows: pXRF; wavelength-dispersive X-Ray fluorescence (WDXRF); and flame atomic absorption spectrometry (FAAS) after acid digestion with aqua regia (reference method). Results of the three analytical methods were used to generate block models through Leapfroag Geo 6.0 software. Portable XRF data presented a strong positive correlation (>0.70) with the results obtained by the FAAS. In addition, pXRF performed better than WDXRF, with less dispersed values compared to FAAS. Similar distribution maps were generated using the three methods of analysis. After correction, the average Cu content from the pXRF-generated block model was only 0.15% lower than that derived from FAAS data. Therefore, pXRF is a fast, portable, non-destructive, low-cost, accurate and recommendable method for mining front sample analysis and to assist the quality control and geoscience teams in decision-making for feeding the mineral processing plant.