Multi-method Characterization Research Articles

Novel insights into PAHs accumulation and multi-method characterization of interaction between groundwater and surface water in middle Yangtze River: Hydrochemistry, isotope hydrology and fractionation effect.

To meet the challenge of water quality protection and management in the middle Yangtze River and understand the accumulation mechanism of PAHs in aquatic complexity systems, caused by hydro-chemical changes, anthropogenic and geological activities, and intensive surface water-groundwater interaction, a comprehensive study is urgently needed. The study investigated the pollution levels, potential sources, accumulation mechanism, and groundwater- surface water interaction of polycyclic aromatic hydrocarbons (PAHs) in wet and dry seasons of the middle Yangtze River. There was no significant difference of PAHs accumulation between wet and dry seasons of the middle Yangtze River. PAHs occurrence in the middle Yangtze River was dominated by the input of tributary. Phenanthrene and Naphthalene were still the dominant species of PAHs. Coal combustion (CC) and biomass burning (BB) were the major contributor for the PAHs occurrence. However, the CC apportionment concentration increased by 6.18ng·L-1 from wet to dry season, suggesting higher density of coal consumption in dry season. The potential mechanism of PAHs occurrence was demonstrated by the mantel test and structural equation model (SEM). Results revealed that the pollution of the middle Yangtze River could be mainly affected by primary emission in wet and dry seasons due to the significant positive effect between eutrophication levels and PAHs pollution sources. Meanwhile, the difference in redox conditions could directly affect the fate of pollutants (including the valence state transformation of nitrogen and phosphorus). The stronger interaction of groundwater and surface water in dry season was presented by hydrochemistry and isotope hydrology (δ18O and δ2H). The similar result was also evidenced by fractionation effect of PAHs, because more similar behaviors of characteristic pollutants were observed in dry season. Consequently, PAHs can be considered as an effective geochemical tracer and further expanded their toxic effects through the surface water-groundwater interaction.

Multi-method characterization of 50-year-old mass concrete from the nuclear power plant Unterweser in Germany: A forensic approach

Concrete core samples extracted from the base of the 50-year-old reactor building at the Unterweser nuclear power plant in Germany were analyzed using contemporary and complementary experimental techniques. The analysis focused on qualitative and quantitative assessments of the mineralogical composition of ingredients, mixture composition, aggregate size distribution, presence of cracks, porosity, and compressive strength. Optical microscopy revealed insignificant micro-cracking in the concrete matrix, while the presence of blast furnace slag was clearly visible. Petrographic analysis of polished and thin sections has enabled the estimation of the concrete mixture composition and the grain size characteristics of the aggregates. The aggregates consist of quartz, silt, and volcanic rock with minor amounts of fossil-bearing grains. Pore size distribution obtained from mercury intrusion porosimetry (MIP) reveals that the concrete has a relatively refined pore structure. Hydration products in the matrix, i.e., hardened paste, were analyzed using powder X-ray diffraction (p-XRD) and thermogravimetry (TGA). Furthermore, backscattered electron (BSE SEM) image analysis was conducted to quantify the original mixture composition, including cement and slag contents, and water/binder ratio. This study emphasizes strategic and practical aspects of conducting in-depth analysis on hardened concrete samples that are several decades old and may serve as a general guideline for similar inquiries in diverse concrete structures.

Multimethod characterization of geogenic sources of fluoride, arsenic, and uranium in Mexican groundwater

Geogenic groundwater F, As and U affect drinking-water availability and safety, with up to 60% of groundwater sources in some regions contaminated by more than recommended concentrations. As a result, an estimated 300–500 million people are at risk of severe health impacts and premature mortality. In the regions of Chihuahua, Zacatecas and Salinas, San Luis Potosí, Mexico (Sierra Madre Occidental), concentrations of fluoride (F), arsenic (As) and uranium (U) have been detected in groundwater above national and international drinking water standards. These elevated concentrations have been associated mainly with geogenic sources in volcanic rocks and basin fill sediments. However, the specific host phases and processes that release these toxic elements into groundwater have never been identified.In a new multi-method approach that combines classical approaches of hydrochemistry, petrography, and geochemistry, with more advanced techniques such as Raman spectroscopy (RS), scanning electron microscopy (SEM), electron microprobe (EMP) and laser ablation LA-ICP-MS, this research proposes an innovative methodology for the characterization and identification of F, As and U bearing phases in volcanic rocks and sediments, as well as some of the processes favoring the mobilization of these elements to groundwater. Groundwater chemical composition allowed the identification of 3 groundwater flow systems: a) local flows, hosted in basin-fill sediments with average temperatures of 21.7 °C, and low As (≈6.2 μg L−1), F (≈0.5 mg L−1) and U (≈1.1 μg L−1) concentrations; b) intermediate flows, characterized by average temperatures of 24.5 °C, and intermediate concentrations of As (≈17.7 μg L−1), F (≈1.1 mg L−1) and U (≈4.2 μg L−1); c) regional flows, circulating mainly through rhyolites and ignimbrites, temperatures that can reach up to 36.6 °C, and higher concentrations of As (≈36.5 μg L−1), F (≈2.6 mg L−1) and U (≈7.4 μg L−1). The presence and distribution of As, F and U in groundwater are associated with the local, intermediate and regional Tóthian flow systems proposed. Through microanalytical analyses, it was possible to identify F-rich minerals like fluorapatite (≈2.3 wt%), biotite (≈1.8 wt%) and fluorite (≈37 wt%). Glassy matrix rich in As (≈0.83–163 μg g−1), U (0.15–11.7 μg g−1) and F (200–1600 μg g−1) was mainly found in rhyolites and ignimbrites from the Tertiary volcanic outcrops of the tectonostratigraphic province of the Sierra Madre Occidental, and basin-fill sediments derived from these rocks. Based on the present study, the groundwater As, F, and U anomalies in the different study zones are associated with ignimbrites and rhyolites considered as their primary source, where processes like weathering, dissolution and devitrification, are directly linked to variations in the concentrations of these elements.This multi-method approach proposes a new efficient way to identify geogenic sources associated with F, As and U in groundwater, especially in regions where groundwater is the main source of supply. The outcome of this research can explain the possible reason behind the high concentrations of F, As and U in a number of regional groundwater flow systems which are well documented cases in volcanic regions of the world and Mexico. The results obtained through the analysis of water-rock interaction in this research can be applied to other semi-arid regions with geogenically impacted aquifers, due to the geological and climatic similarity with numerous volcano-sedimentary basins around the world.

Multi-method characterization of sandstone pore size distribution heterogeneity and its influence on porosity and permeability variation

Multi-method characterization of sandstone pore size distribution heterogeneity and its influence on porosity and permeability variation

Multi-method characterization of groundwater nitrate and sulfate contamination by karst mines in southwest China

Groundwater contamination by nitrate and sulfate in mining areas is a significant challenge. Consequently, the inputs sources of these contaminants and their evolution have received considerable attention, with the knowledge gained critical for improved management of water quality. This study integrated data on multiple stable isotopes and water chemistry data and a Bayesian isotope mixing model to investigate the relative contributions of inputs sources of sulfate and nitrate sources to bodies of water in a karst mining area in southwest China. The outcomes indicated that hydrochemical component in the water bodies of the study area is mainly derived from the dissolution of silicate rocks, carbonate rocks and sulfate minerals as well as the oxidation of sulfides. The human and agricultural wastewater, soil nitrogen, and fertilizers were the predominant inputs sources of nitrate to the mine water environment; the predominant inputs sources of sulfide were mineral oxidation, evaporite dissolution, atmospheric deposition, and sewage. Groundwater is mainly recharged from atmospheric precipitation, and surface water is closely hydraulically connected to groundwater. Nitrogen and oxygen isotope composition and water chemistry indicative of nitrification dominate the nitrogen cycle in the study area. The oxidation of pyrite and bacterial sulfate reduction (SRB) had no significant impact on the stable isotopes of groundwater. The results of this study demonstrate the inputs of different sources to nitrate and sulfate in karst mines and associated transformation processes. The results of this study can assist in the conservation of groundwater quality in mining areas and can act as a reference for future related studies.

Multi-method characterization of a commercial 1.2 Ah sodium-ion battery cell indicates drop-in potential

Multi-method characterization of a commercial 1.2 Ah sodium-ion battery cell indicates drop-in potential

Multi-method characterization of the recent sediment from the Dibi subsidence lake in the tropical Adamawa region (central Cameroon): Implications for the palaeoenvironmental reconstruction

The evolution and functioning of various tropical ecosystems is poorly understood due to a lack of quantitative techniques to characterize the physicochemical composition of soils and sediment. Here, a detailed multi-method study of lithological changes is provided from a core taken from the silted-up Dibi subsidence lake (central Cameroon). To unravel the provenance of sediment, mineral constituents, and organic matter sources, an array of tools are applied including a spectrophotometer, a laser particle sizer, Rock-Eval pyrolysis, X-ray diffractometer (XRD), a portable X-ray fluorescence (XRF) spectrometry, and an inductively coupled plasma-atomic emission spectroscopy (ICP-AES) instruments. The studied core consists of light-colored deposits at the base (Unit 1) overlain by dark humic deposits (Unit 2). The sediment is very well graded (grading index Sd < 0.35Ф), indicative of bottom suspended to rolling transport. Unit 1 is characterized by relatively low values of total organic carbon (TOC: 2%–5%) whereas the dark Unit 2 has high contents of TOC (10%–33%). The core shows a high oxygen index (OI) value (average = 207 mg carbon dioxide (CO2)/g TOC) and a low hydrogen index (HI) value (average = 107 mg hydrocarbon (HC)/g TOC). This indicates highly altered organic matter (OM), likely from decomposed terrestrial plants. The chlorophyll-α fingerprint (peak around 675 nm) also reveals an autochtonous primary production of organic matter. The mineralogical assemblage of Unit 2 comprises kaolinite, quartz, feldspars, montmorillonite, ilmenite, siderite, gibbsite, rutile, and anatase whereas that of Unit 1 is similar but differs with the presence of illite and the absence of gibbsite. The high titanium dioxide (TiO2) and zirconium (Zr) contents confirm that the source rocks also are comprised of granites, and gneiss without volcanic rocks, such as basalts and trachytes. The source rocks have been intensively weathered using some parameters such as ln(Al2O3/Na2O), K2O/Rb, K/Al, and weathering indices, where Al2O3 denotes aluminum oxide, Na2O denotes sodium oxide, K2O denotes potassium oxide, Rb denotes rubidium, K denotes potassium, and Al denotes aluminum. The enrichment factors (EF) of redox-sensitive trace elements and their relation with TOC, the negative values of manganese/iron ratio (Mn∗) associated to three elemental ratios (cupper/zinc (Cu/Zn), thorium/uranium (Th/U), and vanadium/chromium (V/Cr)) attest to the predominance of sub-oxic to anoxic bottom waters in Dibi lake during sediment deposition. The data also show low primary productivity at the base of the core, followed by an increase towards the top, linked to the intensification of weathering and facilitated by humid climatic conditions, usually increase terrestrial input and palaeoproductivity. The petrological data show a generally warm and humid palaeoclimate. This climatic variation has contributed to the large spread of the savannah and disappearance of the forest. This study sheds light on the late Pleistocene to Holocene palaeoenvironment evolution of the Adamawa region which could be integrated into the context of the Pleistocene to Present regional evolution of the tropical palaeoenvironment.

Multi-method characterization of anodic oxidation of a titanium alloy in fluoride-containing electrolytes

Multi-method characterization of anodic oxidation of a titanium alloy in fluoride-containing electrolytes

Multi-method characterization of rare blue quartz-bearing metavolcanic rocks of the Rio dos Remédios Group, Paramirim Aulacogen, NE Brazil

The Rio dos Remédios Group comprises a supracrustal sequence that occupies the base of the Espinhaço Supergroup, São Francisco Craton, Brazil. Its basal formation, Novo Horizonte, crops out in the Paramirim region mainly as metavolcanic rocks that represent one of the fewer occurrences of blue quartz phenocrysts in South America. Their mineralogy consists of quartz and K-feldspar phenocrysts, whereas biotite, muscovite, fluorite, allanite, chlorite, sericite, zircon, and opaque phases occur immersed in a quartz-feldspar-rich groundmass. Such heterogeneous composition is also supported by x-ray diffraction and chemical data. Electron probe microanalysis in some samples revealed the presence of two distinct groups of biotite (magmatic and neoformed), in addition to the presence of iron-rich white mica and almost pure orthoclase feldspar. Our data suggest that the studied metavolcanic rocks have maintained their magmatic characteristics, which were progressively overprinted by hydrothermal fluids and ductile-to-brittle deformation. The magmatic mineralogy is akin to strongly peraluminous and alkaline magmas, common in anorogenic settings – a fertile site for the origin of blue quartz-bearing rocks worldwide.

Multi-pulse agglomeration effects on ultrashort pulsed direct laser interference patterning of Cu

Surface functionalization by biomimetic patterns in the micro- and nanometer scale is well-established in a wide range of applications. The finely tuned surface properties are directly related to both primary and sub-pattern morphology of the applied topographies, which must be well-adjusted for maximum functionalization efficiency. In this light, the role of proceeding surface modification and its effect on pattern formation alongside multi-pulse ultrashort pulsed direct laser interference patterning (USP-DLIP) of Cu are investigated in detail by applying a multi-method characterization approach. It was shown that aside of topographical remodeling, USP-DLIP processing parallelly affects chemistry and the mechanical deformation state of the substrate surface, which in turn considerably influences laser/material interaction via incubation. An in-depth investigation of the individual and combined impacts of these substrate alterations on localized optical absorptance reveals how primary and sub-pattern formation dynamically respond to process induced surface modification. The DLIP-specific incubation impact on pattern morphology increases with inverted relation to pattern scale. The findings of this study provide a profound insight in the predominant physical interactions involved in pattern formation arising from the mutual influence between laser irradiation and substrate modification during USP-DLIP-processing of Cu allowing for high precision micro- and nanometer scaled pattern design.

A multi-method characterization of Elasmobranch & Cheloniidae communities of the north-eastern Red Sea and Gulf of Aqaba.

The Red Sea is particularly biodiverse, hosting high levels of endemism and numerous populations whose extinction risk is heightened by their relative isolation. Elasmobranchs and sea turtles have likely suffered recent declines in this region, although data on their distribution and biology are severely lacking, especially on the eastern side of the basin in Saudi Arabian waters. Here, we present sightings of elasmobranchs and sea turtles across the north-eastern Red Sea and Gulf of Aqaba collected through a combination of survey methods. Over 455 survey hours, we recorded 407 sightings belonging to 26 elasmobranch species and two sea turtle species, more than 75% of which are of conservation concern. We identified 4 species of rays and 9 species of sharks not previously recorded in Saudi Arabia and report a range extension for the pink whipray (Himantura fai) and the round ribbontail ray (Taeniurops meyeni) into the Gulf of Aqaba. High density of sightings of conservation significance, including green and hawksbill sea turtles and halavi guitarfish were recorded in bay systems along the eastern Gulf of Aqaba and the Saudi Arabian coastline bordering the north-eastern Red Sea, and many carcharhinid species were encountered at offshore seamounts in the region. Our findings provide new insights into the distribution patterns of megafaunal assemblages over smaller spatial scales in the region, and facilitate future research and conservation efforts, amidst ongoing, large-scale coastal developments in the north-eastern Red Sea and Gulf of Aqaba.

Delayed circadian rhythms and insomnia symptoms in obsessive-compulsive disorder

BackgroundAccumulating evidence implicates sleep and circadian rhythm disturbance in obsessive-compulsive disorder (OCD). However, a multimethod characterization of sleep and circadian rhythms in OCD, their association with symptom severity, and the functional relationship between these variables is lacking. MethodsThe present study measured multiple indicators of sleep and circadian rhythms in a sample of adults with OCD, adults without OCD, and healthy controls (n = 74). Participants completed measures of morningness-eveningness, delayed sleep-wake phase disorder (DSWPD), insomnia symptoms, and OCD symptoms, as well as one week of sleep monitoring via a sleep diary and actigraphy. ResultsDelayed circadian rhythms (higher eveningness, later mid-sleep timing, and higher rates of DSWPD) and higher insomnia symptoms were observed in those with OCD compared to healthy controls, as well as associations between delayed circadian rhythms and insomnia symptoms and OCD symptom severity across the full sample. Further, insomnia symptoms mediated the relationship between delayed circadian rhythms and OCD symptoms. In contrast, there were no links between total sleep time or sleep quality and OCD. LimitationsData collection during COVID-19 pandemic, correlational data, no physiological measure of circadian rhythms. ConclusionsThese findings highlight a robust association between delayed circadian rhythms and OCD and suggest insomnia symptoms may be one mechanism in this relationship. Sleep and circadian rhythm disturbance may be novel targets for OCD treatment.

Multimethod characterization of terracotta figurines and lime mortar from the elite burials Shoroon Bumbagar I and II, Mongolia

AbstractThe multi‐analytical approach, including X‐ray fluorescence (XRF), X‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy with X‐ray (SEM‐EDX), was applied to terracotta figurines, mural plaster, and local clay sources coming from two elite burials in Mongolia—Shoroon Bumbagar I and Shoroon Bumbagar II—dated to the second half of the VII century AD. The aims of this study were: (1) by comparing the major composition of body samples with those of the ancient Tang sancai kilns to identify the origin of raw materials; and (2) to track changes in the manufacturing technology. Analysis of CaO, Fe2O3, TiO2, and K2O, which were crucial for distinguishing the provenance of red bodies, confirmed the local production of terracotta figurines. Furthermore, this study helped us attain a deeper understanding of the Tang sancai at both Shoroon Bumbagar sites, geographically located on both banks of the Tuul River yet separated in time by a few decades; it suggests the movement of two groups of artisans using different technologies to make Tang sancai locally by incorporating local tastes and traditions.

Actinide Coordination Chemistry on Surfaces: Synthesis, Manipulation, and Properties of Thorium Bis(porphyrinato) Complexes.

Actinide-based metal-organic complexes and coordination architectures encompass intriguing properties and functionalities but are still largely unexplored on surfaces. We introduce the in situ synthesis of actinide tetrapyrrole complexes under ultrahigh-vacuum conditions, on both a metallic support and a 2D material. Specifically, exposure of a tetraphenylporphyrin (TPP) multilayer to an elemental beam of thorium followed by a temperature-programmed reaction and desorption of surplus molecules yields bis(porphyrinato)thorium (Th(TPP)2) assemblies on Ag(111) and hexagonal boron nitride/Cu(111). A multimethod characterization including X-ray photoelectron spectroscopy, scanning tunneling microscopy, temperature-programmed desorption, and complementary density functional theory modeling provides insights into conformational and electronic properties. Supramolecular assemblies of Th(TPP)2 as well as individual double-deckers are addressed with submolecular precision, e.g., demonstrating the reversible rotation of the top porphyrin in Th(TPP)2 by molecular manipulation. Our findings thus demonstrate prospects for actinide-based functional nanoarchitectures.

Toward better characterization of restricted and repetitive behaviors in individuals with germline heterozygous PTEN mutations.

This study aimed to further our understanding of restricted and repetitive behaviors (RRB) among individuals with germline pathogenic mutations in PTEN by providing multimethod characterization and comparison of key RRB subdomains across individuals with PTEN mutations with autism spectrum disorder (ASD) (PTEN-ASD), with PTEN mutations without ASD (PTEN-No ASD) and with ASD and macrocephaly but without PTEN mutations (Macro-ASD). Of 86 total research participants, 38 had PTEN-ASD (Mage = 8.93 years, SDage = 4.75), 25 Macro-ASD (Mage = 11.99 years; SDage = 5.15), and 23 PTEN-No ASD (Mage = 8.94 years; SDage = 4.85). The Repetitive Behavior Scale-Revised (RBS-R) and the Autism Diagnostic Interview-Revised (ADI-R) were used as measures of distinct RRB domains. There were significant group differences in the RBS-R repetitive motor behaviors (RMB; F= 4.52, p= 0.014, ω2 = 0.08), insistence on sameness (IS; F= 4.11, p= 0.02, ω2 = 0.05), and circumscribed interests (CI; F= 7.80, p= 0.001, ω2 = 0.14) scales. Post hoc comparisons showed that the PTEN-No ASD group had significantly lower RMB, IS, and CI scores compared to both PTEN-ASD and Macro-ASD groups. Importantly, PTEN-No ASD group still showed elevated RRB levels. Furthermore, there was a portion of individuals in PTEN-No ASD group whose Full-Scale Intelligence Quotient (FSIQ) was >70 that did not show floor level scores in the RMB domain. After adjusting for age and FSIQ scores, group differences were no longer statistically significant. RMB, IS, and CI domains showed distinct association patterns with sex, age, and FSIQ. This investigation provides the largest and most comprehensive characterization of distinct RRB domains in individuals with PTEN mutations to date. Despite the limitations, our findings have important assessment and treatment implications.

Exploration of material characteristics of tantalum borosilicate glasses by experimental, simulation, and theoretical methods

We aimed to perform a multimethod characterization of the nuclear shielding ability of some tantalum borosilicate glasses. Accordingly, gamma-ray attenuation parameters of glasses with the nominal composition of xTa2O5-(50-x)BaO–25B2O3–15SiO2–10CaO (x = 0, 4, 8, 12, and 15 wt%) were extensively evaluated by experimental, simulation, and theoretical methods. Firstly, amorphous structures of the glasses were determined by X-ray diffraction measurements. The linear attenuation coefficients of the glasses were experimentally measured with a NaI (Tl) (7.62 cm × 7.62 cm) detector. Accordingly, the values obtained were compared with the program XCOM and the general-purpose Monte Carlo simulation code FLUKA at photon energies from 81 to 2614 keV along with gamma-ray transmission values. Furthermore, linear attenuation coefficients were used to calculate other related parameters, such as mass attenuation coefficients, half-value layers, mean free paths, effective atomic numbers and effective electron numbers, total molecular cross sections, total atomic cross sections, and radiation protection efficiency. It was found that the XCOM and FLUKA values of the shielding parameters are in satisfactory agreement with experimental values. Experimental mass attenuation coefficients at a photon energy of 662 keV were 0.075379, 0.075936, 0.076493, 0.077051, and 0.077469 cm2/g for xTa2O5-(50-x)BaO–25B2O3–15SiO2–10CaO with x = 0, 4, 8, 12, and 15 wt%, respectively, whereas effective atomic numbers were 19.27, 19.42, 19.56, 19.70, and 19.81, respectively. Among the samples examined, the highest linear attenuation coefficients, mass attenuation coefficients, and effective atomic and electron numbers, and the lowest half-value layers and mean free paths were reported for 15Ta2O5–35BaO–25B2O3–15SiO2–10CaO, with a material density of 4.610 g/cm3.

Sequential Hydrothermal Processing of Sewage Sludge to Produce Low Nitrogen Biocrude

A hydrothermal pre-treatment has been developed to improve sewage sludge quality or to produce low nitrogen biocrude via hydrothermal liquefaction (HTL) in a subsequent step. The mild hydrothermal pre-treatment (150 °C) step was performed with deionized water, sulfuric acid (0.5 M), or citric acid (0.5 M) to solubilize nitrogen containing compounds in the aqueous supernatant. Downstream, the residual solid material was liquefied with the addition of sodium carbonate via hydrothermal liquefaction (350 °C). The pre-treatment with citric acid transferred up to 66.7 wt. % of nitrogen into the aqueous supernatant, while 62.0 wt. % of carbon was recovered in the solid. Due to the pre-treatment lipids retained in the sewage sludge solid, which increased the favored biocrude yield up to 42.9 wt. % and the quality evaluating value H/Ceff ratio significantly to 1.48. Multi-method characterization of the resulted biocrude samples showed a lower concentration of N-heterocycles, while long-chain aliphatics and free fatty acid are increased.

Multi-method geochemical characterization of groundwater from a hypogene karst system

An approach, combining several geochemical methods, was used to determine the groundwater properties and components of a hypogene karst system, where sampling is restricted only to the spring sites, and with a limited number of available sampling locations. Radiogenic isotopes (3H, 14C) were used to constrain the groundwater mean residence time and separate different groundwater components. Noble gases, stable isotopes of water (δ18O, δ2H), dissolved inorganic carbon (δ13C) and dissolved sulfate (δ34S, δ18O), and major ion and trace element composition were used to identify the source of water, its chemical evolution and water–rock interactions, as well as to identify the contribution and composition of endogenic gases. This approach was applied to three low-temperature thermal springs located in Mariovo (North Macedonia) associated with fossil hypogene caves, previously identified by morphological and geochemical studies of caves and cave deposits. Based on the obtained results, the main studied springs represent an output part of a regional hypogene karst groundwater system with a deep-circulating (~1 km), old (~15 ka), thermal (≥60 °C) water, which mixes with young (<50 years), cold (<14 °C) and shallow epigene karst groundwater. The output parts are structurally controlled, at the interception of low topography and deep faults, along which the groundwater interacts with deep-seated gases, dominantly CO2 of metamorphic origin (δ13C of +4.5‰ VPDB), with some contribution of mantle helium. The thermal karst groundwater interacts at depth with volcanic rocks from the nearby Neogene-Quaternary volcanic complex, as well as with metamorphic basement rocks and granitoids.

Multi-method characterization approach to facilitate a strategy to design mechanical and electrical properties of sintered copper

Advanced die application materials, utilizing pressure-less sintered copper, show great prospects regarding cost effectiveness, power density, withstanding high switching speeds and temperature loading for novel eco-friendly and high efficiency semiconductors. In general, to preserve high reliability in combination with electrical functionality the design of elastic as well as electrical material parameters is of great importance. Here, we present a multi-method characterization approach to understand the impact of the morphology on the elastic as well as electrical behavior, which facilitates a strategy to design the relevant material parameters by tuning the morphology. Nano-SEM/FIB tomography and SEM/EBSD are applied to probe the morphology of three representative copper films. Nanoindentation and 4-point probe are used to extract the elastic modulus and specific electrical resistivity, respectively. The evaluated material parameters are compared with modeling results using the analyzed image data as an input. For the crucial image analysis, we develop a validated objective image analysis workflow. We obtain a quantified insight about the effect of the heterogeneous morphologies on the elastic modulus and specific electrical resistivity, thereby delivering important information about the necessary homogeneous copper morphology- and nano-scale pore-design. The strategy shall provide design guidelines to ensure reliable and high-performance die attachments.

A multi-method characterization of natural terrestrial birnessites

Abstract With a focus on a large set of natural birnessites collected from terrestrial, freshwater systems, we applied and compared the capabilities of X-ray diffraction (XRD), extended X-ray absorption fine structure (EXAFS), Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) to characterize crystal structure and chemistry. Using XRD, we successfully identified 3 of the 11 natural birnessite samples as hexagonal ranciéite-like phases, but the remaining samples yielded less interpretable “3-line” diffraction patterns with broad, asymmetrical peaks at d-spacings of ~7.2, ~2.4, and ~1.4 Å. EXAFS analysis suggested that many of these samples had characteristics of both triclinic and hexagonal birnessite. However, application of EXAFS to the ranciéite-like phases yielded unreasonably high concentrations of triclinic birnessite as an intergrowth, calling into question the use of synthetic hexagonal H-birnessite as an appropriate standard in the linear combination fitting of EXAFS data for natural birnessites. FTIR spectroscopy of the “3-line” birnessite samples successfully distinguished triclinic and hexagonal constituents, and analyses of peak positions suggested that natural birnessites occur as a full spectrum of triclinic and hexagonal intergrowths. XPS analysis of these samples revealed that higher Mn3+ concentrations relative to Mn2+ and Mn4+ are correlated to increased proportions of triclinic birnessite.