Elemental Distribution Maps Research Articles

Ultrathin Metal–Organic Framework Nanosheets-Derived Yolk–Shell Ni 0.85 Se@NC with Rich Se-Vacancies for Enhanced Water Electrolysis

We present a controlled fabrication of selective ultrathin metal–organic framework (MOF) nanosheets as preassembling platforms, yolk–shell structured with a few-layered N-doped carbon (NC) shell-en...

Mechanical and ultrasonic characterisation of copper-nickel diffusion bonded joints

ABSTRACT The diffusion bonding of commercially pure Cu/Ni was made to diffuse at different bonding conditions allowing the bonding to proceed across the planar interfaces. The mechanism, microstructure and mechanical properties which are the effects of diffused bonding were studied. The Nondestructive Ultrasonic C-scan testing method was used to characterise the bond interface. The area of fraction bonded, and its reflection coefficients were computed using ultrasonic C-scan images to determine the quality of bonding. The inferences arrived based on nondestructive testing were checked by conventional destructive test methods which were well correlated. The SEM micrograph was used to compute the interface line width of the diffused bond. The EDS was used to study the mapping of elemental distribution and the fractured surface area of the diffused bonded joints.

Microdistribution of Magnetic Resonance Imaging Contrast Agents in Atherosclerotic Plaques Determined by LA-ICP-MS and SR-\u03bcXRF Imaging

PurposeContrast-enhanced magnetic resonance imaging (MRI) has the potential to replace angiographic evaluation of atherosclerosis. While studies have investigated contrast agent (CA) uptake in atherosclerotic plaques, exact CA spatial distribution on a microscale is elusive. The purpose of this study was to investigate the microdistribution of gadolinium (Gd)- and iron (Fe) oxide-based CA in atherosclerotic plaques of New Zealand White rabbits.ProceduresThe study was performed as a post hoc analysis of archived tissue specimens obtained in a previous in vivo MRI study conducted to investigate signal changes induced by very small superparamagnetic iron oxide nanoparticles (VSOP) and Gd-BOPTA. For analytical discrimination from endogenous Fe, VSOP were doped with europium (Eu) resulting in Eu-VSOP. Formalin-fixed arterial specimens were cut into 5-μm serial sections and analyzed by immunohistochemistry (IHC: Movat’s pentachrome, von Kossa, and Alcian blue (pH 1.0) staining, anti-smooth muscle cell actin (anti-SMA), and anti-rabbit macrophage (anti-RAM-11) immunostaining) and elemental microscopy with laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and synchrotron radiation μX-ray fluorescence (SR-μXRF) spectroscopy. Elemental distribution maps of Fe, Eu, Gd, sulfur (S), phosphorus (P), and calcium (Ca) were investigated.ResultsIHC characterized atherosclerotic plaque pathomorphology. Elemental microscopy showed S distribution to match the anatomy of arterial vessel wall layers, while P distribution corresponded well with cellular areas. LA-ICP-MS revealed Gd and Fe with a limit of detection of ~ 0.1 nmol/g and ~ 100 nmol/g, respectively. Eu-positive signal identified VSOP presence in the vessel wall and allowed the comparison of Eu-VSOP and endogenous Fe distribution in tissue sections. Extracellular matrix material correlated with Eu signal intensity, Fe concentration, and maximum Gd concentration. Eu-VSOP were confined to endothelium in early lesions but accumulated in cellular areas in advanced plaques. Gd distribution was homogeneous in healthy arteries but inhomogeneous in early and advanced plaques. SR-μXRF scans at 0.5 μm resolution revealed Gd hotspots with increased P and Ca concentrations at the intimomedial interface, and a size distribution ranging from a few micrometers to submicrometers.ConclusionsEu-VSOP and Gd have distinct spatial distributions in atherosclerotic plaques. While Eu-VSOP distribution is more cell-associated and might be used to monitor atherosclerotic plaque progression, Gd distribution indicates arterial calcification and might help in characterizing plaque vulnerability.

Equipment design and performance characterization of full field x-ray fluorescence (FF-XRF) element distribution imaging system with combined collimating lens (CCL).

This work describes a full field x-ray fluorescence element distribution imaging system with a combined collimating lens (CCL), which is more suitable for a higher x-ray energy range (12 keV-30 keV). The system consists of an optical-use charge-coupled device (CCD) camera coupled to a combined collimating lens (CCL), which includes pinhole collimator and x-ray window, x-ray tube, and sample room. The continuously variable magnification of 0.5-2 is achieved under a compact structure. The x-ray spectrum and two-dimensional element distribution mapping of the irradiated sample are obtained by processing a series of images acquired by using the CCD camera in a single photon counting mode. The energy resolution is 275 eV at the reference energy of 14.957 keV (yttrium Kα, Z = 39). The limit of detection is 46.41 ppm by measuring yttrium standard solution. The spatial resolution is 135 μm when using a 100 μm pinhole at the magnification of 1. Samples made by metal foils and mineral pigments are tested, and the results proved that the system was reliable when detecting elements of a high atomic number.

Geopolymerization of class C fly ash: Reaction kinetics, microstructure properties and compressive strength of early age

The main objective in this study is to elucidate the geopolymerization of Class C fly ash at different solid-to-liquid ratio (1.0-3.0) by using heat evolution analysis. Differential Scanning Calorimeter was used to monitor heat evolution. The calculated heat evolved was utilized to analyze the reaction kinetics using Johnson-Mehl-Avrami-Kolmogrov Model and correlate with the compressive strength and microstructural properties encompassing morphology, functional group, phase analysis, and elemental distribution. The heat evolution was found to increase with increasing solid-to-liquid ratios. The nucleation mechanism of geopolymerization of Class C fly ash was governed by instantaneous heterogeneous nucleation with rod-like growth. Solid-to-liquid ratio of 2.5 was concluded as optimal ratio due to its great performance for strength development. Meanwhile the contribution of calcium (Ca) and iron (Fe) was confirmed due to the presence of Si-O-Ca and Si-O-Fe bonds in the functional group analysis, which was further confirmed by phase analysis and elemental distribution mapping.

Tracking elemental changes in an ischemic stroke model with X-ray fluorescence imaging

Stroke is a leading cause of long-term disability in adults and a leading cause of death in developed nations. The cascade of cellular events and signalling that occur after cerebral ischemia are complex, however, analyzing global element markers of metabolic state affords the means to monitor stroke severity, status of injury, and recovery. These markers provide a multi-parameter method for assessing changes through the post-stroke time course. We employ synchrotron-based elemental mapping to follow elemental changes in the brain at 1 h, 1-, 2-, and 3-days, and at 1-, 2-, 3-, and 4-weeks post-stroke in a photothrombotic stroke model in mice. Our analysis reveals a highly consistent metabolic penumbra that can be readily identified based on the level of dysregulated potassium and other key elements. Maps of elemental distributions are also useful to demarcate events in the cellular response to the inflammatory cascade, including ion dysregulation, recruitment of cells to the lesion, and glial scar formation.

Ecological risk potential assessment of heavy metal contaminated soils in Ophiolitic formations

The purpose of this study is to generate maps of contamination risk for cadmium (Cd), copper (Cu), lead (Pb), nickel (Ni), and zinc (Zn) in soils of a large alluvial fan located in Neyriz, Iran and to investigate their possible entry into the food chain. To this aim, the concentrations of the heavy metals of the soils are measured. The Geo-accumulation index (Igeo), Muller index, and potential ecological risk index are then used to evaluate soil contamination. The spatial distribution map of elements is also prepared using the kriging method. The results show that the Cd concentration in soils (mean 23 mg/kg) is 10–40 times higher than the global standard threshold (0.30–0.70 mg/kg), the Ni concentration (mean 13 mg/kg) is lower than the threshold (34 -12 mg/kg), the Cu concentration (mean 19.39 mg/kg) is below the threshold (24-13 mg/kg), the Zn concentration (mean 14.11 mg/kg) is also below the threshold (45–100 mg/kg), and the Pb concentration (mean 93.78 mg/kg) is higher than the threshold (44-22 mg/kg). The accumulation index values for Pb and Cd are 1.61 and 5.3, respectively, which decrease from the top to bottom of the study area. The enrichment factor values for Cu, Zn, Pb, Cd, and Ni are 0.43, 0.14, 4.60, 62.57, and 0.27, respectively, which also decrease from top to bottom. The accumulation index values in the soils confirm the occurrence of contamination and further indicate that the elements in the soils originated from local materials and Ophiolitic formations masses in the area. Overall, this research for the first time investigates the effect of natural factors (geological formation) on the soil and plant pollution in the study area and shows that, in addition to pollution by human activity, natural factors such as type of formation can lead to soil and plant pollution.

Dating mafic magmatism by integrating baddeleyite, zircon and apatite U–Pb geochronology: A case study of Proterozoic mafic dykes/sills in the North China Craton

Direct dating of mafic dykes/sills is crucial for understanding mantle geodynamic evolution and crust-mantle interaction, but is also challenging, especially in ancient samples. Here, we provide a reliable approach for dating Proterozoic mafic dykes/sills through an integrated investigation of U–Pb isotopes and elemental distribution maps of the coexisting baddeleyite, zircon and apatite. This study focuses on Paleo- to Neo-Proterozoic mafic dykes/sills in the North China Craton.In the studied samples, baddeleyite is undoubtedly magmatic, with sensitive high resolution ion microprobe (SHRIMP) 207Pb/206Pb ages that may record crystallization ages of the dykes/sills. Common lead incursion along rims and fractures of baddeleyite is identified via laser ablation quadrupole inductively coupled plasma mass spectrometry (LA-Q-ICP-MS) elemental mapping as the likely origin of age uncertainties. In contrast, magmatic zircons from the Proterozoic mafic intrusions are somewhat affected by metamictization as roughly indicated by high alpha dose (Dα), and thus show intricate U–Pb isotopic features. Intensely metamict zircons are susceptible to Pb loss due to fluid infiltration, as clearly illustrated by opposing enrichment trends of Pb and U in zircon maps. Where metamict zircons are unaffected by fluid alteration, they are able to preserve the original 207Pb/206Pb ratios and thus give high precision age constraints on emplacement of the ancient dykes/sills.As for apatites, abundant euhedral coarse-grained crystals were separated from the mafic rocks, rendering them suitable for LA-Q-ICP-MS measurement. U–Pb data define Tera-Wasserburg isochrons with lower intercept ages that match crystallization of the host rocks. Age uncertainties of this method lie in instrumental analysis errors caused by low concentrations of U, Pb and a low proportion of radiogenic Pb in the total Pb, with these parameters commonly showing consistent enrichment trends from crystal cores to rims. By combining U–Pb dating and elemental mapping, this study provides a novel approach to the geochronology of mafic rocks, by highlighting the potential of ubiquitous apatite, offering additional means for error analysis and age interpretation of baddeleyite and zircon.

In situ macro X‐Ray fluorescence scanning on a Leonardo da Vinci portrait

Recently, an oil‐on‐panel painting, portraying Leonardo da Vinci, was found in the monastery of Camaldoli (Arezzo, Italy). The painting comes from a private donation and, over time, it never was moved from the monastery or loaned to museums or art galleries for exhibitions. Historians hypothesise that the painting could be a seventeenth‐century copy of a portrait or a self‐portrait of Leonardo da Vinci. Although, almost certainly, the panel was not signed by Leonardo, it raised a great interest for art experts, since the copy could be the outstanding testimony left to us of an original Leonardo's masterpiece, which is gone lost. The ICRCPAL in Rome, in collaboration with the ISPC‐CNR and the INFN‐LNS of Catania, started a scientific investigation of the painting based on the use of non‐invasive techniques. Macro X‐ray fluorescence imaging technique (MA‐XRF) was employed to document, for the first time, the nature of original pigments composing the pictorial and priming layers. The results allowed to better elucidate the painting technique, also to know the original look of degraded areas, suggesting an appropriate restoration and conservation policy. Novel information has been obtained concerning the pictorial process, since elemental distribution maps revealed an underpainting below the Leonardo portrait. Despite the cleaning process of the panel before its reuse, some pictorial details remained visible to the MA‐XRF analysis, allowing to infer the presumed figure hidden behind the figure of Leonardo.

Development of the Silicon Drift Detector for Electron Microscopy Applications

Abstract:

Spatial distribution of heavy metals in soils of the flood plain of the Seversky Donets River (Russia) based on geostatistical methods.

Soil contamination by heavy metals (HM) is a worldwide problem for human health. To reduce risk to human health from exposure to toxic chemicals associated with soil contamination, it is necessary to monitor and assess HM concentrations in the soil for places where the concentration exceeds the acceptable levels. Spatial patterning is a necessary tool for assessment of the exposure risk of HM contamination. Soil sampling (n = 65) was carried out in technogenically polluted soils located at Rostov oblast to study the content and spatial distribution of four HM (Cu, Zn, Pb, and Cr) in the surface layer (0-20cm) of the impact zone of former Lake Atamanskoe (floodplain of the Seversky Donets River valley, Rostov region) with an area of 3.91 km2. Extremely high values of HM concentrations were found with the maximum values of 702mg/kg, 72,886mg/kg, 2300mg/kg, 259mg/kg for Cu, Zn, Pb, and Cr, respectively. Inverse distance-weighted (IDW) interpolation was used to prepare 3D monoelement images of HM. Lognormal kriging and indicator kriging techniques were applied to create elemental spatial distribution maps and HM probability maps. The results showed that the total content of Cu, Zn, Pb, and Cr was moderately spatially dependent (nugget-to-sill ratio ranged from 31 to 38%), whereas the contamination index Zc formed strong spatial dependence patterns (nugget-to-sill ratio ranged from 0 to 21.4%). The obtained results of this study could serve as a guide to the authorities in identifying those areas which need remediation. Moreover, this study provides a tool for assessing the hygienic situation in the vicinity of Kamensk-Shakhtinsky (Rostov region) for decision making that can help to minimize the environmental risk of technogenic soil contamination of HM.

Copper Oxides on a Cu Sheet Substrate Made by Laser Technique

This paper presents results from the production of copper oxide layers on a Cu sheet substrate using diode and Yb:YAG disc lasers operating in the wavelength ranges of 808–940 nm and 1030 nm. The parameters of these layers were compared with the layer obtained in the thermal process of copper oxidation at 300 °C in an infrared (IR) furnace in a natural atmosphere. Investigations into the layers mentioned above, concerning their topography, chemical composition and roughness, were made using scanning electron microscopy (SEM) and atomic force microscopy (AFM). A hot-point probe was used to determine and check the type of conductivity of the copper oxide layers formed. The optical band gap energy was estimated by applying the Kubelka–Munk method based on spectrophotometric data. Cross-sections and the element distribution maps were made using transmission electron microscopy (TEM). The phase analysis was investigated by the X-ray diffraction method (XRD). In sum, controlled laser oxidations of copper sheets allow for the formation of a mixture of Cu2O and CuO phases. The diode laser allows the production of a layer of copper oxides with a phase composition comparable to the oxides produced by the thermal oxidation method, while the distribution of high phase uniformity in the cross-section of the layer enables the process using a Yb:YAG disc laser.

Elemental mapping of plant leaves by MeV glass capillary microbeam PIXE

MeV-ion microbeam using the capillary technique was home-developed based on the 1.7-MV tandem accelerator and beamline at Chiang Mai University. The system consisted of the capillary itself, a capillary holder, a holder swing mechanism, and a system support frame with a micrometer for vertical micro-adjustment. The glass capillaries had various sizes in a range of 10 – hundreds μm in the exit inner diameter. In this study, the capillary ion-microbeam was applied in elemental concentration distribution mapping of plant leaves using particle induced X-ray emission (PIXE) analysis. The interests were focused on difference in the elemental concentrations distributed between the leaf vein and lamina of local longan leaves which were sprayed by chemical fertilizer and pesticide and leaves of Peperomia pellucida, a herb, which was cultured by dissolved supplement solution of various nutrients. 1D and 2D maps of detected elements from the longan and herb leaves across vein and lamina were generated respectively, showing redistributions of the elements between vein and lamina due to the human activities. Details of the mapping results are reported and discussed.

Adsorption of Remazol Brilliant Violet-5R Textile Dye from Aqueous Solutions by Using Eggshell Waste Biosorbent

Based on the well-known excellent adsorbent ability of chicken eggshells, the adsorptive capacity and mechanism of Remazol Brilliant Violet-5R (RBV-5R) dye by eggshell was investigated. Exploiting the high surface-area-to-volume ratio and porous structure of this natural adsorbent, the developed procedure showed to be useful for the efficient adsorption of RBV-5R dye from contaminated water. The protocol was thoroughly optimized by investigating the effect of the dye concentration, biomass-contaminated water ratio, particle size of the adsorbent, pH and temperature, as they are key factors in the efficiency of the dye removal process. The eggshell material was characterized by different types of microscopy techniques (stereo, polarization, SEM) as well as elemental analysis (element distribution mapping, EDX), Raman spectroscopy and BET-surface density measurements. EDX, FTIR and Raman spectroscopy proved the presence of the adsorbed dye on the surface of the biomaterial. It was shown that under optimal conditions, the environmentally friendly and inexpensive eggshell could be a reliable adsorbent for Remazol dye removal from wastewater.

Ion, electron and laser beams for Cultural Heritage investigations by Czech-Italian collaboration

An overview of physical investigations of cultural heritage samples using ion and laser beams performed in the frame of the international collaboration between the University of Messina (Italy) and the Nuclear Physics Institute-ASCR (Czech Republic) is presented. Solid samples are analysed in high vacuum using particle induced X-ray emission, Rutherford backscattering spectrometry, elastic recoil detection analysis, prompt γ activation analysis, nuclear reaction analysis, laser ablation, mass spectrometry, scanning electron microscopy, and many more. The elemental composition of the sample, the trace elements, the depth profiles, the morphology and the comparison between samples and references are reported. Both electron and ion microbeams are employed to have details of the spatial distribution maps of elements of interest.

Differential X-Ray Attenuation in MA-XRF Analysis for a Non-invasive Determination of Gilding Thickness.

When investigating gilded artifacts or works of art, the determination of the gilding thickness plays a significant role in establishing restoration protocols or conservation strategies. Unfortunately, this is done by cross-sectioning the object, a destructive approach not always feasible. A non-destructive alternative, based on the differential attenuation of fluorescence radiation from the sample, has been developed in the past years, but due to the intrinsic random nature of X-rays, the study of single or few spots of an objects surface may yield biased information. Furthermore, considering the effects of both porosity and sample inhomogeneities is a practice commonly overlooked, which may introduce systematic errors. In order to overcome these matters, here we propose the extrapolation of the differential-attenuation method from single-spot X-ray fluorescence (XRF) measurements to macro-XRF (MA-XRF) scanning. In this work, an innovative algorithm was developed for evaluating the large amount of data coming from MA-XRF datasets and evaluate the thickness of a given overlapping layer over an area. This approach was adopted to study a gilded copper-based buckle from the sixteenth to seventeenth century found in Rome. The gilded object under investigation was also studied by other analytical techniques including scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS). Previous results obtained from SEM-EDS were used to confront the data obtained with the proposed methodology and validate it. MA-XRF elemental distribution maps were fundamental in identifying and choosing sampling areas to calculate the thickness of the gilding layer, avoiding lead islands present in the sample that could negatively influence the results. Albeit the large relative standard deviation, the mean thickness values fell within those found in literature and those obtained from previous studies with SEM-EDS. Surface fissure has been found to deeply affect the results obtained, an aspect that is often disregarded.

Assessment and characterization of groundwater quality under domestic distribution using hydrochemical and multivariate statistical methods in Bafia, Cameroon

The best knowledge of physico-geochemical content of water helps to cope with adequacy between water availability and its importance. Thus, in BAFIA where groundwater is used in households, it is mandatory to evaluate and characterize the quality of that water. BAFIA is an important area of Cameroon due to its geographical position, growing population and associated needs. Located between an equatorial climate in the western region and a humid tropical climate in the eastern region, this area contains an aquifer system that represents sequences of shales, mica quarry, biotite gneiss, post-tectonic granites, and ortho-amphibolite. Groundwater flows aquifers recharge areas and provides base flows to supply drinking water to study area. The objective of this work was to assess the physicochemical and bacteriological quality of groundwater, to explain the phenomena that cause its mineralization in and around the BAFIA area and to correlate these different ions. We only included boreholes that had a good flow rate to meet the need to supply a large number of populations with water for domestic use. We conducted an analytical study of the physicochemical and bacteriological parameters of the elements collected from the water samples. The results were processed using hydro-chemical methods (Piper diagram, distribution maps of chemical elements) for a study of water typology and multivariate statistical analysis techniques. Principal component analysis (PCR) and ascending hierarchical classification (CHA) analysis were used to determine the phenomena causing water mineralization and the links between these waters, respectively. Our results showed that: the waters analyzed in the study area were slightly basic and moderately mineralized. Chemical parameter grades were below the world health organization (WHO) standard; except for iron. Most of the water was chlorinated and sulfated calsic and magnesic. Three phenomena have been at the origin of water mineralization: anthropogenic activity, recharge of groundwater (soil infiltration) and water-rock contact (main ion production mechanism).

Construction and application of a micro-area polarized energy dispersive X-ray fluorescence spectrometer with polycapillary X-ray lens in a conventional laboratory

The polarized energy dispersive X-ray fluorescence analysis method can effectively reduce detection limits by improving the signal-to-noise ratio. However, the lack of high-power density and small analysis area of the polarized X-ray beam has hindered more accurate analysis of samples in conventional laboratory. A polycapillary X-ray lens can be applied to micro-area analysis. Therefore, a micro-area polarized energy dispersive X-ray fluorescence spectrometer based on a bent highly oriented pyrolytic graphite and a polycapillary X-ray lens is proposed. The polarization degree of the polarized X-ray beam is 99.76% and its focal spot size is 338.8 μm × 404.5 μm. The new spectrometer feasibility was proved by effective production of high-resolution element distribution maps of a holly (Ilex chinensis Sims) leaf sample.

Simulation of salt spray corrosion behaviour of micro-arc oxidation coating by laser induced Ag infiltration

Micro-arc oxidation (MAO) coating was initially prepared on 6061 Al alloy, and subsequently coated with Ag using magnetron sputtering. Laser beam scan (LBS) treatments were then applied to infiltrate the sputtered Ag into the MAO coating in order to simulate the corrosion behaviour of the MAO coating during the neutral salt spray test (NSST). Cross-sectional morphologies and Ag element distribution maps were studied by using the field emission scanning electron microscopy (FESEM) on the MAO-Ag coated samples after LBS infiltration. The results showed that there existed the micro-cracks with tree-root or lightning shape within the MAO coating. Interconnected aggregates, including micro-pores, large cavities far beneath the surface and tree-root like micro-cracks, served as complex corrosion channels during salt spray corrosion. Through these corrosion channels, the salt spray penetrated gradually into the interface between the MAO coating and the original Al substrate, thus causing corrosion of the Al substrate during the NSST. The LBS treatment is presented as a method to explore the subtle micro-crack and pore channels associated to the MAO coating and to provide information that paves the way towards understanding of corrosion phenomena in these porous systems.

Application of LA ICP-MS analysis of arsenopyrite to gold metallogeny of the Meguma Terrane, Nova Scotia, Canada

Investigation of gold metallogeny in the Paleozoic Meguma terrane (Canada) is conducted through LA-ICP-MS analysis of arsenopyrite collected from eight slate-belt style vein gold deposits using a novel approach integrating elemental distribution maps and their derived elemental paragenesis with multi-element binary plots. The data reveal two distinct gold events: 1) an early event characterized by a Co-Ni-Mo-Sb-Se elemental association related to initial growth of arsenopyrite that reflects the presence of invisible gold (>10 ppm); and 2) a second event, spatially associated with late fracture sets, that is characterized by an Al-Ti-V-Mn element association and reflects either remobilization or upgrading of primary invisible gold and is manifest as visible gold.The results of this study indicate a complex and protracted history of gold mineralization which has important ramifications for the Meguma gold deposits, as well as other orogenic gold districts globally. In the case of the Meguma Terrane, it involves an initial gold event that is followed by element mobilization and, in the case of precious metals (Au, Ag), an upgrading through a zone refining process. In addition, the variable coupling and decoupling of elements is only revealed using in-situ derived LA-ICP-MS data.