Scanning Electron Microscopy With Energy Dispersive Spectroscopy Research Articles

Post-depositional alterations of terrestrial and marine finds of Roman ceramics from Crikvenica production centre (NE Adriatic, Croatia) – A contribution towards chemometric classification

• Different post-depositional alterations of Roman ceramics from Crikvenica's pottery production were identified. • The effects of seawater, anoxic marine sediments and desalination are recognizable by multi-analytical methods. • Multivariate statistics on FT-IR spectra represent a suitable method for a first screening and identification of representative samples of each sub-group. • Ceramics excavated from the site of the workshop (local ceramics) can be used as a reference group for future classification studies of Roman ceramics from the Crikvenica production centre. Different post-depositional conditions and after-recovery treatments may provoke pronounced physicochemical alterations that can make archaeological ceramics’ classification and comparison difficult even when its provenance is known. The present study describes the differences in the chemical composition verified on sherds of Roman ceramics produced in Crikvenica (NE Adriatic, Croatia). Inductive coupled plasma mass spectrometry (ICP-MS), scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS), as well as Fourier transform infrared spectroscopy (FT-IR) were applied to characterise the chemical composition and post-depositional alterations in ceramics recovered onshore and underwater. Chemometrical treatment of ICP-MS results of elemental composition and FT-IR absorption bands was performed using univariate and multivariate statistical tools. Principal component analysis (PCA) led to clear distinction of several clusters of examined samples, i.e. samples from the mainland, samples from the sea bottom, and desalinated samples. All sherds that have undergone desalination represent a distinct sub-group by means of changes in the ratio of accumulated chemical elements. It was established that accumulation of Ca, Mg and Na and formation of salts such as FeS, Mg 6 Al 2 CO 3 (OH) 16 ·4(H 2 O), and CaCO 3 reflect post-depositional environments and post-recovery treatments in terms of desalination and specific marine underwater conditions (oxic and anoxic). Our results outlined a pattern of post-depositional alterations that could be applied in upcoming classification studies. Roman ceramics produced in Crikvenica and excavated from the workshop possess attributes of a reference group, revealing that Ho, Ce, La, Lu, Tb, Gd, Eu and Sm are the elements least susceptible to post-depositional alterations.

Mechanistic insights and multiple characterizations of cadmium binding to animal-derived biochar

Cattle-derived biochar (CB), which is derived from industrial pyrolysis of cattle carcasses in harmless treatment plants, is a naturally occurring mineral form of carbonate-bearing hydroxyapatite (CHAP) with a small amount of elemental carbon. CB has 4.02% of carbonate content, which falls under the B-type substitution of CHAP. In this work, the Cd(II) sorption capacity of CB was determined to be 0.82 mmol/g, with 97.6% of the Cd(II) uptake contributing to CHAP and only 2.36% of the Cd(II) uptake contributing to the elemental carbon component. The calculation and linear combination fitting (LCF) of Cd L3-edge X-ray absorption near-edge structure (XANES) analysis indicated that the contributions of Cd(II) species to CB presented the following order: ion exchange (57.6%–61.0%) > precipitation (24.4%–29.9%) > surface complexation (12.5%–13.4%). The depth dependent X-ray photoelectron spectroscopy (XPS) showed the presence of ion exchange, which is accompanied by intraparticle diffusion. LCF of XANES and Rietveld analysis of X-ray diffraction (XRD) demonstrated that Cd(II) was precipitated in the form of Cd5H2(PO4)4·4H2O on the CB surface. Furthermore, the precipitate was directly observed and identified by scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDS). Consequently, we revealed the intricate binding mechanism of Cd(II) to CHAP-rich CB and confirmed the importance of surface precipitation.

Analytical and computational study of three coptic icons in Saint Mercurius Monastery, Egypt

Three wooden Coptic icons located at Saint Mercurius Monastery in Tamooh, Giza, Egypt were comprehensively investigated in order to determine the possible causes of their deterioration. Samples from every paint used in each icon were collected spanning from the outermost varnish layer down to the ground layer. Investigation was carried out using Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS), Energy-dispersive X-ray spectroscopy (EDX) and X-ray fluorescence (XRF). For interaction between the icon layers DFT calculations at B3LYP/6-31g(d,p) level were conducted in order to study the effect of humidity on the reactivity of the binder material and its possible role in the deterioration of the icons.

Comparison of Elemental Analysis Techniques for Fly Ash from Municipal Solid Waste Incineration using X-rays and Electron Beams

With the rapid expansion of the waste incineration business both in Europe and globally, there is a growing need for the elemental analysis for fly ash from municipal solid waste incineration. In this work, samples of washed and unwashed ash from municipal solid waste incineration in Sundsvall are evaluated. Qualitative analysis and semi-quantitative analysis are used to compare two elemental analysis methods, scanning electron microscope with energy dispersive spectroscopy (SEM-EDS) and X-ray fluorescence (XRF) measurement. Both methods are used to retrieve the difference in elemental composition between washed and unwashed fly ash. SEM-EDS accurately detects light elements from well-prepared samples in a vacuum environment, while, for online measurements, XRF is a potential method that analyses hazardous metal content in the fly ash.

Experimental examination and thermodynamic description of the ternary Bi-Ge-Ga,Zn systems

Due to the wide application of systems based on germanium ternary Bi-Ga-Ge and Bi-Ge-Zn systems were experimentally tested in this study. Used experimental techniques were scanning electron microscope with energy dispersive spectroscopy (SEM-EDS), x-ray diffraction (XRD) and differential thermal analysis (DTA). Three groups of samples were prepared and tested. Alloys were from two isothermal sections at 100 and 300 °C and three vertical sections. Obtained results of experimental tests were compared with predicted phase diagrams. Comparison of EDS and DTA results with calculated phase diagrams of the ternary Bi-Ga-Ge system results in good agreement. While for Bi-Ge-Zn was necessary to introduce new ternary parameters. Introduced ternary parameters were based on experimental results from this study. The thermodynamic descriptions of the ternary Bi-Ga-Ge and Bi-Ge-Zn systems have been developed by using CALPHAD method. Reasonable agreement between experimental data and the calculated phase diagrams has been reached for both ternary Bi-Ga-Ge and Bi-Ge-Zn systems. The liquid projection and invariant equilibria have been calculated by using obtained thermodynamic parameters.

Effect of selective-precipitations process on the corrosion resistance and hardness of dual-phase high-carbon steel

It is commonly known that precipitation of secondary phase in non-ferrous alloys will affect the mechanical properties of them. But due to the nature of dual-phase low-alloy high-carbon steel and its high potential of precipitation of cementite, there is limited study on tailoring the mechanical and corrosion properties of this grade of steel by controlling the precipitation of different phases. Predicting and controlling precipitation behaviour on this grade of steel is of great importance towards producing more advanced applications using this low-cost alloy. In this study the new concept of selective-precipitation process for controlling the mechanical and corrosion behaviour of dual-phase low-alloy high-carbon steel has been introduced. We have investigated the precipitation of different phases using in-situ observation ultra-high temperature confocal scanning laser microscopy, image analyser – ImageJ, scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS) and electron probe microanalysis (EPMA). Volume fraction of each phase including retained austenite, martensite and precipitated phases was determined by X-ray diffraction (XRD), electrochemical corrosion test by Tafel extrapolation method and hardness performance by nanoindentation hardness measurement. The experimental results demonstrated that, by controlling the precipitations inside the matrix and at grain boundaries through heat treatment, we can increase the hardness of steel from 7.81 GPa to 11.4 GPa. Also, corrosion resistance of steel at different condition has been investigated. This new approach will open new possibility of using this low-cost steel for high performance applications.

Reactivity and Microstructure of Metakaolin Based Geopolymers: Effect of Fly Ash and Liquid/Solid Contents.

Geopolymers are inorganic binders based on mixtures of an aluminosilicate powder with an alkali-silicate solution. Properties of geopolymers are strongly determined by the type of reactive solid, the liquid/solid ratio of paste and, amongst others, the Si/Al ratio of the formed geopolymer network. In this study, fly ash blended metakaolin based geopolymers with varying liquid/solid ratios (l/s), activated by potassium silicate solution, are investigated. Reactivity of metakaolin and fly ash was investigated by powder X-ray diffraction (XRD) and dissolution tests. Reactivity, mechanical properties and microstructure of hardened pastes were analyzed by setting and compressive strength tests, mercury intrusion porosimetry (MIP), capillary water absorption tests, thermogravimetric analysis-differential scanning calorimeter (TGA-DSC), isothermal calorimetry and scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS). The results show that substitution of metakaolin by fly ash as well as variation of l/s brings advantages up to a certain degree, but also has a considerable influence on the pore size distribution, mechanical properties, Si/Al ratio of the geopolymer network and the content of bound water.

Organic petrography of Leonardian (Wolfcamp A) mudrocks and carbonates, Midland Basin, Texas: The fate of oil-prone sedimentary organic matter in the oil window

Abstract To better understand evolution of oil-prone sedimentary organic matter to petroleum and expulsion from source rock, we evaluated organic petrographic features of Leonardian Wolfcamp A repetitive siliceous and calcareous mudrock and fine-grained carbonate lithofacies cycles occurring in the R. Ricker #1 core from Reagan County, Midland Basin, Texas. The objectives of the petrographic investigation were to estimate thermal maturity, identify organic matter types and abundances, and identify the presence or absence of migrated hydrocarbons in organic-lean carbonate layers. An integrated analytical program included geochemical screening [total organic carbon (TOC) content by LECO, programmed pyrolysis by hydrocarbon analyzer with kinetics (HAWK) including analysis of solvent-extracted samples], X-ray diffraction mineralogy, organic petrography, scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) including correlative light and electron microscopy (CLEM), and micro-Fourier transform infrared spectroscopy (μ-FTIR) analyses of solid bitumen. The data indicate all samples are early to middle oil window thermal maturity with solid bitumen reflectance (BRo) values of 0.55–0.86% and Tmax of 440–455 °C. Organic matter is predominantly solid bitumen (as identified by optical microscopy) in all lithofacies with minor contributions from inertinite. Solid bitumen abundance decreases from siliceous mudrock (TOC >3.0 wt%) to calcareous mudrock (TOC 1.0 to 3.0 wt%) to fine-grained carbonate (TOC

The effect of gastric acid on chitosan modified glass ionomer cement: SEM-EDS.

This study aimed to use scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) to examine the elements that passed into the gastric acid solution after the application of a gastric acid erosive cycle to chitosan modified glass ionomer cement (GIC). Chitosan modified GIC samples were obtained by adding chitosan (vol/vol) of 5 and 10% to GIC for the experimental groups. These two experimental groups and a control group were subjected to gastric acid erosive treatment for 60 s six times a day for 10 days. The sample surfaces were coated with approximately 1 nm of gold to increase conductivity with the Q 150R ES device (Quorum Technologies, East Sussex, England). Surface topography images were obtained with a SEM. Besides, EDS analysis was also determined the number of elements graphically in the region where the fast electron beam hit. In the samples examined, the amount of element was determined. After gastric acid application, cracks and voids were observed on the surfaces of the samples. In the EDS analysis of the 5 and 10% chitosan modified GIC and control groups, Si, Al, Na, and F was found. It is necessary to investigate the antibacterial properties and physical properties of chitosan modified glass ionomer-free elements and fluorine ions using advanced techniques.

Performance evaluation of waste iron shavings (Fe0) for catalytic ozonation in removal of sulfamethoxazole from municipal wastewater treatment plant effluent in a batch mode pilot plant

Feasibility of iron shavings (Fe0) as a low-cost catalyst was evaluated in catalytic ozonation for degradation of sulfamethoxazole (SMX). The characterization of the catalyst studied by a variety of techniques like scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR). Experimental results indicated a first order kinetics for Fe-based catalytic ozonation (O3/Fe0) and sole-ozonation (O3) in the removal of SMX with slightly greater rate constant for O3. In the both processes, the removal efficiency of SMX was more than 99% at the first 5 min. Average COD removal efficiency in the O3/Fe0 process was about 1.36 times greater than O3. The main intermediates detected by LC-MS/MS were 3-Amino-5-methylisoxazole, benzoquinone, sulfanilic acid, hydroxyl-SMX and nitroso SMX. The mineralization of SMX significantly increased concentration of sulfate and nitrate. Fe0 enhanced ozone utilization and transfer rate. Fe0 is not requiring any preparation before use and could be a promising catalyst for practical advanced wastewater treatment.

Tribological performance of three fatty acid anion-based ionic liquids (FAILs) used as lubricant additive

This paper studies the tribological behavior of three fatty acid anion-based ionic liquids: methyltrioctylammonium octanoate ([N8881][C8:0]), methyltrioctylammonium laurate ([N8881][C12:0]) and methyltrioctylammonium palmitate ([N8881][C16:0]) used as additive at 0.5, 1 and 2 wt% in an ester base oil. The tribological experiments were performed in two different tribometers: a Bruker UMT-3 using a reciprocating “ball-on-disc” configuration for pure sliding tests and a Mini Traction Machine (MTM) for rolling/sliding tests. After sliding tests, the wear scar was analyzed by scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) and X-ray photoelectron spectroscopy (XPS). Sliding tests results showed both friction and wear reduction of the mixtures with respect to the ester only at 25 °C. The worse tribological behavior at 100 °C could be attributed to the moderate thermal stability of these ionic liquids. Under rolling/sliding conditions, samples displayed similar antifriction and ECR behavior than the base oil at high speeds, changing to a higher friction and lower ECR at low speeds and increasing temperatures. EDX analysis showed mainly the steel disc elements. The XPS oxygen signal showed higher amount of CO bond on the worn surface after reciprocating tests at 25 °C, which could be attributable to IL-surface interaction and can explain the better wear reduction performance.

Mineralogical control and characteristics of rare earth elements occurrence in Carboniferous bauxites from western Henan Province, north China: A XRD, SEM-EDS and LA-ICP-MS analysis

High concentrations of rare earth elements (REE) are found in the bauxite deposits in the Songqi area of Henan Province, North China. However, no studies have been carried out on the occurrences of REE in these bauxite ores. In this study we explored the REE occurrence and their possible enrichment mechanism in the Songqi bauxite deposits using petrographic observation, X-ray diffraction (XRD), scanning electron microscope with energy dispersive spectroscopy (SEM-EDS), and LA-ICP-MS techniques. The major aluminum-rich ore mineral in the Songqi bauxite deposits is diaspore, and other coexisting minerals include clay mineral aggregates, with minor amounts of hematite, pyrite, anatase, and zircon. The bauxite ores are rich in REE and also some other critical metals (Li, Zr, Nb, and Ga). Most of the REE are adsorbed in the form of ions on the surface of clay minerals and diaspore, and some heavy rare earth elements (HREE) exist in the form of xenotime. The SEM-EDS and LA-ICP-MS analyses show that REE is closely related to the content of P and therefore it is possible that other dispersed and minor P-bearing rare earth minerals may occur in the bauxite deposits except for the possible co-adsorption of P and REE in the clays and diaspore.

Electrochemical behavior of praseodymium on the W and Al–Zn electrodes in LiCl–KCl eutectic: A comparison study

A new active Al–Zn electrode for recovering praseodymium (Pr) from spent nuclear fuel in chloride molten salts was proposed in this work. The electrochemical behavior of Pr(III) ions dissolved in LiCl–KCl eutectic and its co-reduction with Al(III) and Zn(II) ions on the W electrode as well as its reduction at the liquid Al–Zn electrode were studied and compared. In addition, the diffusion coefficient of Pr(III) ions in melt was evaluated using semi-integral and semi-differential techniques, respectively. The results showed that the number of redox signals corresponding to Pr–Zn intermetallic compounds are more than that for Pr–Al intermetallics. Potentiostatic and galvanostatic electrolysis were both carried out on various electrodes to identify the formation of different Pr-containing alloys. The characterizations for cathodic deposits obtained were accomplished by using X-ray diffraction (XRD) and scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS). The work described here can broaden the applications of Al–Zn alloys and highlight its potentials in future molten salt electrolysis based spent fuel pyroprocessing.

Geopolymer, Calcium Aluminate, and Portland Cement-Based Mortars: Comparing Degradation Using Acetic Acid

In this paper, we comparitvley studied acetic acid attacks on geopolymer (GP-M), calcium aluminate (CAC-M), and Portland cement (PC-M)-based mortars. Consequent formations of deteriorated or transition layers surrounding the unaltered core material was classified in these three mortars, according to different degradation levels depending on what binder type was involved. Apart from mass loss, hardness, and deterioration depth, their microstructural alterations were analyzed using test methods such as scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS), mercury intrusion porosimetry (MIP), powder X-ray diffraction (XRD), and thermogravimetric analysis-differential scanning calorimeter (TGA-DSC), which showed the different mechanisms for each binder type. Elemental maps revealed the decalcification (PC-M and CAC-M) and depolymerization (GP-M) that occurred across the mortar sections. The mass loss, hardness, and porosity were the least affected for GP-M, followed by CAC-M. These results points out that geopolymer-based mortars have improved acid resistance, which can be used as a potential alternative to conventional cement concretes that have been exposed to agro-industrial environments.

Conservation state of cast iron metalworks in European street furniture

This work evaluates the state of conservation of three artefacts of historical street furniture in cast iron, dating back to the second half of the nineteenth century and coming from foundries located in Italy, France and Great Britain. Form, distribution and size of graphite in cast irons, and the constituents of microstructures were evaluated by optical microscopy, whereas the alloy composition was determined by scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS). The same analytical technique, in association with Diffuse Reflectance Infrared Fourier Transform (DRIFT) and micro-Raman spectroscopies, was employed to characterize corrosion attack morphology, patina stratification and thickness. The protectiveness of the corrosion layers of the artefacts was evaluated by Electrochemical Impedance Spectroscopy (EIS). The results showed that the microstructure and alloy composition were similar to those frequently encountered in complex shape castings with variable wall thickness. On the corroded surfaces, the graphitization of the cast irons was detected. This phenomenon was accompanied by the deposition of corrosion layers of variable thickness, containing iron oxides, oxy-hydroxides, chlorides and silicon oxides. The corrosion layers of most artefacts showed a poor protectiveness, particularly when they included chlorides, detected in association with akaganeite among corrosion products.

The First Occurrence of Asbestiform Magnesio-Riebeckite in Schists in the Frido Unit (Pollino Unesco Global Geopark, Southern Italy)

In this paper, new mineralogical and petrographical data of asbestiform Magnesio-riebeckite from ophiolite cropping out in the Pollino Unesco Global Geopark (southern Italy) are presented. Magnesio-riebeckite schists with HP-LT index mineral assemblage recorded metamorphic events in blueschist facies in the Frido Unit. Previous toxicological studies showed that asbestiform Magnesio-riebeckite species exhibited high carcinogenicity in previous intraperitoneal injection experiments with rats. The results have been obtained using different analytical techniques such as X-ray fluorescence (XRF), scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS), and electron probe micro analysis (EPMA). Results show that all the samples contain fibrous Magnesio-riebeckite and/or prismatic, acicular crystals in aggregates. The concentration of elements in Magnesio-riebeckite crystals is: Na2O (4.12–6.26 wt%), MgO (8.22–10.87 wt%), FeO (19.07–23.81 wt%), SiO2 (52.05–56.06 wt%), CaO (1.12–4.53 wt%), Al2O3 (1.34–1.93 wt%), and MnO (0.10–0.34 wt%). Magnesio-riebeckite crystals are documented in the Pollino Unesco Global Geopark for the first time. For this reason, the aim of this paper is the characterization of Magnesio-riebeckite to improve the knowledge of this mineral in the studied area, because the release of fibers into the environment is dangerous for human health.

Applying microscopic analytic techniques for failure analysis in electronic assemblies

The present paper gives an overview of surface failures, internal nonconformities and solders joint failures detected by microscopic analysis of electronic assemblies. Optical microscopy (stereomicroscopy) and Fourier-Transform-Infrared (FTIR) microscopy is used for documentation and failure localization on electronic samples surface. For internal observable conditions a metallographic cross-section analysis of the sample is required. The aim of this work is to present some internal and external observable nonconformities which frequently appear in electronic assemblies. In order to detect these nonconformities, optical microscopy, cross section analysis, FTIR-microscopy and scanning electron microscopy with energy dispersive spectrometry (SEM-EDS) were used as analytical techniques.

Approach to the knowledge of preservation of pleistocenic bone: The case of a Gomphothere cranium from the site of Tepeticpac, Tlaxcala, Mexico

An almost complete cranium of a gomphoterium found in Tepeticpac, Tlaxcala, was analyzed with X-ray diffraction (XRD), Petrography and Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM-EDS) to stablish the transformations of the bone during its burial. The analyses assessed that the bone mineral (bioapatite) had suffered modifications in mineral composition, “crystallinity index”, cell parameters and CO2 content. However, the paleohistological structure of the bone was not significantly affected, although evidence of microbial attack was found in the bone surfaces. The filling minerals of bone macro and micro porosity were also analyzed; its main filling minerals are calcite (micrite and sparite), clays, and minerals of volcanic origin.

Silicic protective surface films for pyrite oxidation suppression to control acid mine drainage at the source

The tailings produce acid mine drainage (AMD) due to sulfide minerals, especially pyrite oxidation. AMD has caused serious pollution to the surrounding aquatic and terrestrial ecosystems because of its famous low pH value and high metal and sulfate concentration, which is an urgent environmental problem faced by the world's ore mining industry. Here, we show that silicic protective surface films can suppress the oxidation of pyrite-bearing tailings for AMD control at-source without pre-oxidation of pyrite and solution pH adjuster and buffer. We found that the silicic protective surface films formed by calcium silicate can inhibit the oxidation of pyrite-bearing tailings and reduce the production of AMD through chemical leaching tests. Fourier transform infrared (FTIR) analyses and scanning electron microscopy with energy-dispersive spectrometry (SEM/EDS) confirmed the presence of silicic protective surface films of calcium silicate on the surface of pyrite-bearing tailings.

Artifacts in cranial MRI caused by extracranial foreign bodies and analysis of these foreign bodies.

Purpose:The purpose of our study was to conduct a chemical analysis of extracranial foreign bodies (FBs) causing artifacts in cranial magnetic resonance imaging (MRI) and to investigate the association between chemical composition, magnetic susceptibility, and artifact size.Materials and Methods:A total of 12 patients were included in the study. The FBs responsible for the artifacts were visualized using cranial computed tomography (CT). Artifact-causing FBs were removed from the scalps of 10 patients and analyzed using scanning electron microscope with energy dispersive spectroscopy (SEM-EDS), X-ray diffraction spectroscopy (X-RD), and Fourier-transform infrared spectroscopy (FT-IR). The magnetic susceptibility of the samples was determined using the reference standard material MnCl2.6H2O. The volume of the MRI artifacts was measured in cubic centimeters (cm3).Results:EDS results demonstrated that the mean Fe ratio was 5.82% in the stone samples and 0.08% in the glass samples. Although no phase peaks were detected in the X-RD spectra of the glass samples, peaks of Fe2O3, Al2Ca (SiO4) were detected in the X-RD spectra of the stone samples. The FT-IR spectra revealed metal oxide peaks corresponding to Fe, Al, in the stone samples and peaks confirming Al2SiO5 and Na2SiO3 structures in the glass samples. The mean volumes of the MRI artifacts produced by the stone and glass samples were 5.9 cm3 and 2.5 cm3, respectively.Conclusions:Artifacts caused by extracranial FBs containing metal/metal oxide components are directly associated with their chemical composition and the artifact size are also related to element composition and magnetic susceptibility.