Composition Range Research Articles

Elemental analyses of feldspathic to basaltic soils and rocks on the moon using laser-induced breakdown spectroscopy

In-situ analysis of major elements using laser-induced breakdown spectroscopy (LIBS) is essential for future lunar landing missions, yet its performance under lunar conditions remains not fully understood. This uncertainty arises from the absence of an atmosphere and the diverse range of surface materials, which vary in chemical composition from anorthosites to basalts, and in physical properties from fine regolith to boulders. To address these challenges, we developed and cross-validated a multivariate LIBS calibration model by measuring 169 compressed fine powders of geologic samples under vacuum. These samples fully encompass the bulk composition range of lunar meteorites. We investigated the applicability of the model to a wider range of samples by measuring lunar meteorites, terrestrial anorthites, and lunar simulants in various physical forms, including rock chips and soils with different grain sizes and bulk densities. For powder samples, the quantification accuracy, assessed using root mean squared error (RMSE), resulted in 2.5 wt% SiO2, 0.25 wt% TiO2, 1.2 wt% Al2O3, 1.3 wt% MgO, 1.2 wt% CaO, 0.33 wt% Na2O, 0.47 wt% K2O (0.060 wt% K2O in the <1 wt% range), and 1.5 wt% T-Fe2O3. For rock chip samples, the RMSEs were 3.1 wt% SiO2, 0.32 wt% TiO2, 2.2 wt% Al2O3, 2.5 wt% MgO, 2.0 wt% CaO, 0.33 wt% Na2O, 0.089 wt% K2O, and 2.1 wt% T-Fe2O3. Despite significant differences in physical conditions between powders and rocks, their RMSEs remained consistent within a factor of two. Changes in grain size or bulk density of soils had relatively minor effects on the RMSE. These RMSEs confirm that the quantification accuracy of LIBS is sufficient to distinguish the subgroups within the lunar anorthosite suite (e.g., anorthosites vs. norites) and basalts (e.g., high-Ti vs. low-Ti) across a range of soil types, from coarse to fine and from loose to compact, as well as rocks. Furthermore, our analysis shows that LIBS can differentiate between “purest” and “pure” anorthosites (98 and 95 vol% plagioclase, respectively) based on the 3σ detection limits of Mg and Fe lines. These capabilities of LIBS align well with the goals of future lunar exploration, such as locating ilmenite-rich soils for resource extraction, detecting purest anorthosites to understand early lunar evolution, and identifying noritic impact melts to refine lunar chronology. Overall, our results demonstrate that LIBS serves as a versatile tool for rapid geochemical characterization on the Moon.

Recycled Oceanic Crust in the Source of the Intraplate Changbaishan‐Tianchi Volcano, China/North Korea

AbstractContinental intraplate volcano is an ideal probe to unravel the composition and structure of the deep Earth. The intraplate Changbaishan‐Tianchi volcano was one of the most hazardous eruptions on the Earth's planet. The long‐term activity of this volcano from the Pleistocene to 946 CE has erupted materials with a broad compositional range from basalt to rhyolite, which are expected to be associated with the continuous northeastward subduction of the Pacific plate, but the magma source remains controversial. In this paper, we present a comprehensive data set of in situ zircon Hf and O isotope data, combined with whole‐rock element and Sr‐Nd‐Pb isotope compositions, for selected eruptions of the Changbaishan‐Tianchi volcano, aiming to provide new insights into their magma source and the associated geodynamics. Radiogenic isotopic ratios and incompatible trace element compositions indicate that the erupted volcanic rocks at different stages, although with a varied differentiation degree, were derived from a common magma source characterized by a mixture of DM and EM1 end‐members. Zircon Hf and O isotopes are both relatively homogeneous for different lithologies and eruption stages, with the εHf(t) values varying between −5 and +5, and δ18O values between 3.58‰ and 5.97‰. Modeling of source mixing indicates that high‐temperature altered oceanic crust materials are an important component in the source of Changbaishan‐Tianchi volcano, likely derived from an ancient stagnant slab that has been reactivated by the subduction of the Pacific plate. This study demonstrates that the recycling of deeply subducted oceanic crust is potentially an important source and trigger for continental intraplate volcanism.

Competing Kinetic Consequences of CO2 on the Oxidative Degradation of Branched Poly(ethylenimine).

Amine-functionalized porous solid materials are effective sorbents for direct air capture (DAC) of CO2. However, they are prone to oxidative degradation in service, increasing the materials cost for widespread implementation. While the identification of oxidation products has given insights into degradation pathways, the roles of some species, like CO2 itself, remain unresolved, with conflicting information in the literature. Here, we investigate the impact of CO2 on the oxidative degradation of poly(ethylenimine)-alumina (PEI/Al2O3) sorbents under conditions encompassing a wide range of CO2-air mixture compositions and temperatures relevant to DAC conditions, thereby reconciling the conflicting data in the literature. Degradation profiles characterized by thermogravimetric analysis, in situ ATR-FTIR, and CO2 capacity measurements reveal nonmonotonic effects of CO2 concentrations and temperatures on oxidation kinetics. Specifically, 0.04% CO2 accelerates PEI/Al2O3 oxidation more at low temperatures (<90 °C) compared to 1% and 5% CO2, but this trend reverses at high temperatures (>90 °C). First-principles metadynamics, machine learning accelerated molecular dynamics simulations, and 1H relaxometry experiments show that chemisorbed CO2 acid-catalyzes critical oxidation reactions, while extensive CO2 uptake reduces PEI branch mobility, slowing radical propagation. These contrasting kinetic effects of CO2 explain the complex degradation profiles observed in this work and in prior literature. Collectively, this work highlights the importance of considering atmospheric components in the design of DAC sorbents and processes. Additionally, it identifies the unconstrained branch mobility and local acid environment as two of the major culprits in the oxidation of amine-based sorbents, suggesting potential strategies to mitigate sorbent degradation.

Was the Stonehenge Altar Stone from Orkney? Investigating the mineralogy and geochemistry of Orcadian Old Red sandstones and Neolithic circle monuments

Recent petrological, mineralogical and geochemical investigations of the Stonehenge Altar Stone have negated its source in the Old Red Sandstone (ORS) Anglo-Welsh Basin. Further, it has been suggested that it is time to look wider, across northern Britain and Scotland, especially in areas where geological and geochemical evidence concur, and there is evidence of Neolithic communities and their monuments. In this context the islands of Orkney, with its rich Neolithic archaeology, are an obvious area worthy of investigation. The same techniques applied to investigations of the Altar Stone and ORS sequences in southern Britain have been applied to two major Neolithic monuments on Mainland Orkney, namely the Stones of Stenness and the Ring of Brodgar. In addition, field samples of ORS lithologies from the main stratigraphic horizons on Mainland Orkney have been investigated.Portable XRF analyses of the five exposed stones at the Stones of Stenness and seven of the exposed stones at the Ring of Brodgar show a wide range of compositions, having similar compositions to field samples analysed from both the Lower and Upper Stromness Flagstone formations, with the stones at Stenness appearing to have been sourced from the Upper Stromness Flagstone Formation while the Ring of Brodgar stones possibly being sourced from both formations. Examination of the mineralogy of ORS field samples and the Stonehenge Altar Stone, using a combination of X-ray diffraction, microscopy, Raman spectroscopy and automated SEM-EDS shows there to be no match between the Orkney samples and the Altar Stone. Only two samples from Orkney showed the presence of baryte, a characteristic mineral of the Altar Stone. Another key discriminant is the presence of abundant detrital K-feldspar in all of the Orkney field samples, a mineral which has only very low abundance in the Altar Stone. In addition, the regularly interstratified dioctahedral/dioctahedral smectite mineral tosudite is present in the clay mineral assemblage of the Altar Stone, but not detected in the Orkney samples.It is concluded that the Altar Stone was not sourced from Mainland Orkney, despite considerable evidence for long-distance communications between Orkney and Stonehenge around 3000/2900 BCE.

Design of Oxidation-Resistant Alloys Using Combinatorial Approaches with Chemically Graded Materials

This work introduces a new high-throughput method to characterize the oxidation behavior of chemically graded Ni-based alloys in order to feed databases destined to numerical metallurgy approaches. A Ni–wCr–3Al (w ∈ [0, 30]) chemically graded material was obtained from two homogeneous samples by a diffusion couple method at 1300 °C for 100 h. The composition range was selected in order to observe the three types of oxidation behavior identified in the reference work of Giggins and Pettit (Giggins and Pettit in Journal of The Electrochemical Society 118:1782, 1971). The excellent agreement between simulated and experimental diffusion profiles validated the experimental method used to manufacture the chemically graded material (CGM). The CGM was then oxidized at 1200 °C in air. Surface and cross-section characterization was conducted by SEM/EDS and Raman spectroscopy to identify the oxides formed on the CGM. To accelerate the Raman characterization treatment, a method linking principal component analysis and K-means unsupervised clustering algorithm was developed. It allowed for the identification of the oxide type without peak indexation issues and is well suited for CGM. These results show that results similar to well-recognized reference experiments (Giggins and Pettit in Journal of The Electrochemical Society 118:1782, 1971) can be achieved using only one CGM.

Corrosion behavior of additively manufactured FeCrAl in out-of-pile light water reactor environments

Iron-Chromium-Aluminum (FeCrAl) alloys are candidate materials for the cladding of light water reactor (LWR) fuels. The FeCrAl alloys in general range in Cr composition from 12% (C26M) to 21% (APMT). In this work, the general corrosion behavior of Additively Manufactured (AM) C26M coupons was compared to the behavior of traditional Powder Metallurgy (PM) coupons. Immersion testing were conducted for 12 months at 288 °C and 330 °C in pure water containing either oxygen or hydrogen. Results show that the mass change of AM specimens in hydrogenated water was like the mass change of PM specimens. In oxygenated water, the mass change of AM coupons was higher and less reproducible than for the PM coupons. Porosity in the AM specimens makes their behavior less predictable in high-temperature water.

Extra-terrestrial mantle samples: Rare Earth Element variations and evidence for melt metasomatism in ureilite meteorites

Ureilites are meteorites derived from the mantle of a reduced differentiated asteroid, the “Ureilite Parent Body” (UPB), which was later disrupted by impact with another Solar System body. They have ultramafic compositions dominated mostly by olivine and pigeonite with rare orthopyroxene and augite; aluminous phases are generally absent. Ureilites vary from abundant peridotites to much rarer pyroxenites, and their core olivine compositions range from Fo74 to Fo97 across different samples. The UPB experienced sufficiently high temperatures to undergo silicate partial melting, as shown by depletion in the Light Rare Earth Elements (LREE) in bulk restitic ureilites. Plagioclase and merrillite were probably present in the UPB mantle but have been completely removed during silicate partial melting. Partial melts of the UPB mantle are represented by glassy melt inclusions, igneous clasts in ureilite breccias, cumulus augite in some ureilites, and rare trachyandesitic fragments. These melts are generally intermediate and sub-alkaline in composition, although a few are alkaline. They have more enriched and flatter bulk REE patterns than the restitic ureilites and often show positive Eu anomalies. Glasses (representing melts) in ureilites from this study range from 57 to 79 wt% SiO2. One sample (AhS 22) shows petrographic and geochemical evidence for interaction between magma and the solid UPB mantle by forming metasomatic augite.Silicate minerals in ureilites analysed by LA-ICP-MS are generally LREE-depleted, with negative Eu anomalies. Ureilitic olivines have the lowest REE contents and the smallest negative Eu anomalies. Low-Ca pyroxenes have similar patterns with slightly stronger Eu anomalies. Augites have the highest REE contents and the most negative Eu anomalies. Augites show REE disequilibrium with olivine and low-Ca pyroxene, suggesting that they were not part of the restitic assemblage but were added by silicate melts passing through the UPB mantle, i.e. they are metasomatic in origin. We also discuss the size of the original UPB, using silicate minerals as evidence for it being a typical asteroid rather than a planet-sized object.

Comprehensive study of photoluminescence and device properties in Cu2Zn(Sn1−xGex)S4 monograins and monograin layer solar cells

Ge-alloying of Cu2ZnSnS4 is a promising strategy for producing wide-bandgap absorber materials suitable for use in tandem structures or indoor solar cell applications. Incorporating Ge can suppress Sn-related defects while maintaining the kesterite structure and p-type conductivity throughout the entire range of composition. In this study, Cu2Zn(Sn1−xGex)S4 monograins were synthesized in molten salt by the synthesis-growth method, where value x was varied from 0 to 1, with a step of 0.2. The inclusion of Ge into the crystals was confirmed by energy-dispersive X-ray spectroscopy, Raman spectroscopy, and X-ray diffraction analysis. The bandgaps of Cu2Zn(Sn1−xGex)S4 solid solutions were determined as Eg = 1.50–2.25 eV by external quantum efficiency measurement. A detailed study of temperature and laser power-dependent photoluminescence (PL) for powder crystals with x = 0, x = 0.2 and x = 0.4 revealed that the dominant recombination mechanisms originate from defect clusters involving a shallow acceptor and deep donor defect. Ge-alloying helped to suppress the harmful SnZn donor defects, but at the same time shifted the defects' energy levels deeper into the bandgap. The obtained activation energies indicate that the acceptor defect becomes shallower with the inclusion of Ge. At the mid-temperature range (T = 60–200 K), the presence of two different recombinations was revealed in the system, originating from very closely located PL emission bands.

Ultrasonic powder consolidation of metallic glass/Al-6061 composites

Traditional powder consolidation methods for fabricating metallic matrix composites often require high temperatures, high pressures, and substantial energy consumption. Therefore, developing new processing technologies that can manufacture composites rapidly, efficiently, and economically is crucial. This study introduces ultrasonic powder consolidation process as a novel strategy for fabricating and tuning metallic glass (MG) and aluminum alloy composites. By optimizing the mass ratios of Zr55Cu30Ni5Al10 (at.%) MG to Al-6061 powders, a diverse range of composites with tailored compressive strength and plasticity was achieved. Mechanical testing showed that increasing the aluminum content improved plasticity while maintaining significant strength. Notably, the composite with a 5:5 mass ratio exhibited the best balance of mechanical properties. Morphological characterizations demonstrated excellent densification and uniformity in the composites, with no visible defects and relative densities ranging from approximately 92 %–99 %. Detailed microstructural analysis revealed the formation of a well-bonded interface with a diffusion layer, confirming the metallurgical bonding was facilitated by ultrasonic vibration. Furthermore, the ultrasonic consolidation process enabled the successful fabrication of complex shapes, such as star and gear components, demonstrating the method's potential for advanced manufacturing. These results show that the ultrasonic powder consolidation process is a viable and efficient approach for producing high-quality MG/Al-6061 composites with enhanced mechanical performance and application versatility.

Influence of lithium-ion doping on electrical and dielectric properties of zinc-borate-phosphate glass for improved energy storage

The glass samples with compositional range xLi2O-(40-x)B2O3-25ZnO-35 P2O5(LBZP) (where x = 5, 10, 15, 20, and 25) were prepared with the melt-quench method. The density, molar volumes of these glasses was estimated employing Archimedes’s principle. The electrical properties of these glasses employing the impedance spectrometer have been investigated thoroughly at temperatures ranging from 333 K to 533 K and frequency windows between 20 Hz and 5 MHz. Several theoretical models such as Almond West formalism, correlated barrier hoping model, equivalent circuit models of Nyquist plots, etc., were used to estimate important parameters of the samples such as different conductivity and impedance parameters, the density of states, enthalpy parameters, etc. Dielectric studies of the samples were performed by analysing dielectric and modulus spectra. Bergman's model was used to analyse modulus spectra and Havriliak-Negami (HN) formalism was used to analyse dielectric spectra. Scaling formalism of modulus spectra was used to study the structure and temperature-dependent relaxation mechanism of the charge carriers. It has been shown that the samples with higher lithium content exhibit enhanced ionic and electronic conductivity. It indicates their possible application in electrode materials.

First-principles data for solid solution niobium-tantalum-vanadium alloys with body-centered-cubic structures

We present four open-source datasets that provide results of density functional theory (DFT) calculations of ground-state properties of refractory solid solution binary alloys niobium-tantalum (NbTa), niobium-vanadium (NbV), tantalum-vanadium (TaV), and ternary alloys NbTaV ordered in body-centered-cubic (BCC) structures with 128 Bravais lattice sites. The first-principles code used to run the calculations is the Vienna Ab-Initio Simulation Package. The calculations have been collected by uniformly sampling chemical compositions across the entire compositional range. For each chemical composition, the calculations have been run for 100 randomized arrangements of the constituents on the BCC lattice sites. This sampling methodology resulted in running DFT simulations for a total of 3,100 randomized atomic configurations over 31 chemical compositions for each of the three binary alloys Nb-Ta, Nb-V, Ta-V, and a total of 10,500 randomized atomic structures over 105 chemical compositions for the ternary alloys Nb-Ta-V. For each atomic configuration, geometry optimization has been performed, and the data released contains information about each step of geometry optimization for each atomic configuration.

Copper isotope fractionation during magmatic evolution in a convergent tectonic setting: Constraints from sulfide Cu-S isotopes and whole-rock PGE of the Xiarihamu Ni-Cu sulfide deposit

Nickel and cobalt are potentially critical metals in many countries because of their great significance for national security and economic development, and they are mainly derived from magmatic Ni-Cu‑platinum-group element (PGE) sulfide ore deposits hosted in mafic-ultramafic intrusions. Although Cu isotopes have been used to trace the metallogenic processes in Ni-Cu-(PGE) sulfide deposits, the Cu isotopic fractionation mechanism during magma generation and evolution in convergent tectonic settings is still debated. The Xiarihamu magmatic NiCu sulfide deposit, located in the East Kunlun orogenic belt, northern Tibetan Plateau, is the world's largest known magmatic NiCu sulfide deposit in an orogenic setting. Here we report the whole-rock element and sulfide CuS isotope compositions of samples from the Xiarihamu deposit. The δ65Cu and δ34S values of the sulfide grains from the massive, heavily disseminated, and disseminated sulfide ores range from 0.19 ‰ to 0.79 ‰, and from 4.2 ‰ to 9.4 ‰, respectively. Most of the samples have δ65Cu values higher than normal mantle values, except for two samples with δ65Cu values within the mantle composition range. The whole rock S/Se ratios range from 3200 to 22,500, and the Cu/Pd ratios range from 330 to 820,000, which are also mainly higher than the corresponding mantle values. Modeling calculations of the δ65Cu, S/Se, and Cu/Pd values reveal that the sulfide liquid to silicate melt mass ratio (R factor) is not the main reason for the observed δ65Cu variations in the Xiarihamu deposit. The variations in the Cu/Pd ratios of the whole-rock samples, and the sulfide δ65Cu and δ34S values with depth indicate that sulfide segregation and crustal contamination can reasonably jointly produce the Cu isotope variations in the Xiarihamu deposit, and the variations of samples from different parts of the deposit are caused by variations in these controlling factors. Therefore, Cu isotope fractionation in convergent tectonic settings is mainly caused by magma evolution. The complicated controlling factors of the Cu and S isotopes indicate that the correlation between δ65Cu and δ34S values may not be helpful in evaluating the metallogenic potential of Ni-Cu-(PGE) sulfide deposits. Cu isotopes can be used to ascertain the migration path of magmas.

Petrogenesis of microgranular enclaves in the A-type granitoid Krasnopol intrusion (Mazury Complex, northeastern Poland): Evidence of magma mixing

The origin of magmatic microgranular enclaves has been investigated in the Mesoproterozoic granitoid Krasnopol intrusion (1.5 Ga), part of the AMCG (anorthosite–mangerite–charnockite–granite) Mazury Complex in the East European Craton (NE Poland). The granitoids are ferroan and metaluminous, and display the typical characteristics of A-type granites, with high contents of Zr, Nb, Ga and rare earth elements (REEs). The enclaves are metaluminous and have a broad compositional range with two groups distinguished: silica-poor (45–50 wt% SiO2) and silica-rich (54 to 59 wt% SiO2), the latter overlapping in composition with the granitoid samples. The silica-poor enclaves are enriched in REEs compared to the silica-rich type, while the silica-rich enclaves exhibit trace-element patterns similar to those of the granitoids. Initial whole rock εNd values range between -3.8 and -4.0 for the granitoids and give a slightly wider range from -2.6 to -3.8 for the enclaves. The 87Sr/86Sr initial values vary from 0.7084 to 0.7138 for the granitoids and between 0.7052 and 0.7075 for the enclaves and indicate that the granitoids and enclaves are not isotopically identical. These may suggest that the two magmatic systems represented by the granitoid host rock and the enclaves, were probably derived from different sources, but with sufficient interaction, which led to a progressive change in the composition of the enclaves towards intermediate composition. We suggest that the mafic melts of the enclaves were generated at the base of the thickened crust through partial melting of the lower crustal source, with a significant contribution from mantle material. The increase in temperature resulted in anatexis of the lower crust and the formation of the granitoid parental magma.

Random Copolymers Based on 2-Ethylhexyl Acrylate Exhibit Unusual Glass Transition Breadth and Facile Autonomous Self-Healing over a Broad Composition Range.

Statistical copolymers are commercially important because their properties can be tuned by comonomer selection and composition. Rubbery-state styrene (S)/n-butyl acrylate (nBA) copolymers have previously been reported to exhibit facile, autonomous self-healing over a narrow composition band (47/53 to 53/47 mol%). The need for a narrow composition band is explained by alternating comonomer sequences that accommodate interchain secondary bonding. It is hypothesized that copolymers that achieve interchain secondary bonding without alternating sequences can exhibit facile self-healing over a broad composition range. 2-ethylhexyl acrylate (EHA) is identified as yielding sequence-independent secondary bonding interactions. For these interactions it is tested experimentally by glass transition breadth in rubbery-state S/EHA copolymers, with S/n-hexyl acrylate (nHA) and S/nBA copolymers as controls. The n-alkyl acrylate random copolymers exhibit enhanced glass transition breadths over narrow composition bands that correspond to autonomous self-healing. In contrast, S/EHA copolymers exhibit much greater glass transition breadths than S/nHA and S/nBA copolymers at all compositions tested as well as self-healing of damage over a broad composition range with full tensile-property recovery, often in 3-10h. Characterization of glass transition breadth may serve as a simple screening tool for identifying copolymers that exhibit broad-composition-range, facile, autonomous self-healing and contribute to polymer resilience and sustainability.

Role of Source, Mineralogy, and Organic Complexation on Lability and Fe Isotopic Composition of Terrestrial Fe sources to the Gulf of Alaska.

Iron (Fe) is a key trace nutrient supporting marine primary production, and its deposition in the surface ocean can impact multiple biogeochemical cycles. Understanding Fe cycling in the subarctic is key for tracking the fate of particulate-bound sources of oceans in a changing climate. Recently, Fe isotope ratios have been proposed as a potential tool to trace sources of Fe to the marine environment. Here, we investigate the Fe isotopic composition of terrestrial sources of Fe including glacial sediment, loess, volcanic ash, and wildfire aerosols, all from Alaska. Results show that the δ56Fe values of glaciofluvial silt, glacial dissolved load, volcanic ash, and wildfire aerosols fall in a restricted range of δ56Fe values from -0.02 to +0.12‰, in contrast to the broader range of Fe isotopic compositions observed in loess, -0.50 to +0.13‰. The Fe isotopic composition of the dissolved load of glacial meltwater was consistently lighter compared to its particulate counterpart. The 'aging' (exposure to environmental conditions) of volcanic ash did not significantly fractionate the Fe isotopic composition. The Fe isotopic composition of wildfire aerosols collected during an active fire season in Alaska in the summer of 2019 was not significantly fractionated from those of the average upper continental crust composition. We find that the δ56Fe values of loess (<5 μm fraction) were more negative (-0.32 to +0.05‰) with respect to all samples measured here, had the highest proportion of easily reducible Fe (5.9-59.6%), and were correlated with the degree of chemical weathering and organic matter content. Transmission electron spectroscopy measurements indicate an accumulation of amorphous Fe phases in the loess. Our results indicate that Fe isotopes can be related to Fe lability when in the presence of organic matter and that higher organic matter content is associated with a distinctly more negative Fe isotope signature likely due to Fe-organic complexation.

Strontium isotopes in the atmosphere, geosphere and hydrosphere: Developing a systematic “fingerprinting” framework of rocks and water in sedimentary basins in eastern Australia

Understanding the connection between aquifers, aquitards, and groundwater-dependant ecosystems remains a key challenge when developing a conceptual hydrogeological model. The aim of this study was to develop a systematic strontium isotope (87Sr/86Sr) fingerprinting framework of rocks and water within the sedimentary Surat and Clarence-Moreton basins (SCM basins) in eastern Australia – an area of extensive coal seam gas development and high potential for aquifer and groundwater-surface water connectivity. To do this, new groundwater samples (n = 298) were collected, analyzed and integrated with published data (n = 154) from the basins' major sedimentary, volcanic and alluvial aquifers, including the major coal seam gas target, the Walloon Coal Measures. Samples were also analyzed from rainfall (n = 2) and surface water (n = 40). In addition, rock core samples (n = 39) from exploration and stratigraphic wells were analyzed to determine the range of Sr isotope composition from host rocks. The analyses of cores demonstrate a distinct and systematic contrast in 87Sr/86Sr between different hydrogeological units. This confirms that all major hydrogeological units have a narrow range with unique 87Sr/86Sr population characteristics that are useful for guiding conceptual model development. Comparison with selected hydrochemical and groundwater age tracers (14C and 36Cl) suggests only limited changes of 87Sr/86Sr from recharge beds to the deeper parts of the basins or with a decrease in natural 14C and 36Cl tracer content along flow paths. Stream sampling during baseflow conditions confirms that 87Sr/86Sr in surface waters are similar to those of the underlying bedrock formations. We demonstrated that 87Sr/86Sr analyses of rocks and water provide a powerful hydrostratigraphic and chemostratigraphic fingerprinting framework in the SCM basins, enabling reliable assessments of plausible aquifer and groundwater-surface water interconnectivity pathways. Applied in other complex multi-aquifer sedimentary basins in Australia, and globally, a similar approach can help to constrain conceptual hydrogeological models and facilitate improved water resource management.

An interaction-based mixing model for predicting porosity and tensile strength of directly compressed ternary blends of pharmaceutical powders

Predicting the mechanical properties of powder mixtures without extensive experimentation is important for model driven design in solid dosage form manufacture. Here, a new binary interaction-based model is proposed for predicting the compressibility and compactability of directly compressed pharmaceutical powder mixtures based on the mixture composition. The model is validated using blends of MCC, lactose and paracetamol or ibuprofen. Both compressibility and compactability profiles are predicted well for a variety of blend compositions of ternary mixtures for the two formulations. The model performs well over a wide range of compositions for both blends and better than either an ideal mixing model or a ternary interaction model. A design of experiments which reduces the amount of API required for fitting the model parameters for a new formulation is proposed to reduce amount of API required. The design requires only three blends containing API. The model gives similar performance to the well-known Reynolds et al. model (2017) when trained using the same data sets. The binary interaction model approach is generalizable to other powder mixture properties. The model presented in this work is limited to curve-fitting of empirical compaction models for mixtures of common pharmaceutical powders and is not intended to provide guidance on the practical operating space (or design space) limits.

Predicting phase coexistence and adsorption isotherms of classical and quantum fluids using the microcanonical-ensemble perturbation theory (MEPT)

The Microcanonical-Ensemble Perturbation Theory (MEPT) of Sastre et al. (2018) [7] has been extended to study the vapor-liquid phase coexistence of binary and ternary mixtures of fluids. The attractive interactions between chains of molecules are represented as monomer segments interacting via a square-well pair potential. Calculations for the thermodynamic properties and phase behavior of square-well monomer chains are considered and compared with experimental data. Molecular parameters have been obtained to model the phase behavior of real fluids such as n-alkanes (from C1 to C12), nitrogen, perfluoromethane, carbon dioxide, i-butane, i-pentane, neon, and hydrogen. Furthermore, the capability of the MEPT approach in predicting critical and azeotropic lines of binary and ternary mixtures is explored. The results demonstrate that the MEPT approach provides a robust description of the phase behavior of mixtures containing chains of fluids. Additionally, we have integrated the MEPT approach with the two-dimensional Statistical Associating Fluid Theory for fluids interacting via variable range potentials (SAFT-VR-2D) to investigate the effect of quantum contributions on both phase behavior and adsorption. Remarkable improvements are observed when both higher order perturbation terms of the Helmholtz free energy and quantum contributions are included in the predictions of the phase behavior of quantum fluids such as neon and hydrogen. In all cases, the theoretical results exhibit favorable comparisons with experimental data in a wide range of compositions, pressures, and temperatures.

Harnessing Compositional Gradients to Elucidate Phase Behaviors toward High Performance Polymer Semiconductor Blends.

Polymer semiconductor/insulator blends offer a promising avenue to achieve desired mechanical properties, environmental stability, and high device performance in organic field-effect transistors. A comprehensive understanding of process-structure-property relationships necessitates a thorough exploration of the composition space to identify transitions in performance, morphology, and phase behavior. Hence, this study employs a high-throughput gradient thin film library, enabling rapid and continuous screening of composition-morphology-device performance relationships in conjugated polymer blends. Applied to a donor-acceptor copolymer blend, this technique efficiently surveys a broad composition range, capturing trends in device performance across the gradient. Furthermore, characterizing the gradient library using microscopy and depth profiling techniques pinpointed composition-dependent transitions in morphology. To validate the results and gain deeper insights, uniform-composition experiments were conducted on select compositions within and outside the gradient range. Depth profiling experiments on the constant composition films unveil the presence of the semiconducting polymer at the air interface, with apparent enrichment of the semiconductor at the substrate interface at low ratios of the semiconducting component, transitioning to a more even distribution within the bulk of the film at higher ratios. The generalizability of the gradient approach was further confirmed by its application to a homopolymer under different solution processing conditions.

Micro-scale quantitative analysis of sterol content in liposomes

The high complexity of biological membranes has driven the development and application of a wide range of model membrane systems. Among these models, liposomes are extensively used because of their versatility in mimicking cellular membranes with a wide range of lipid compositions. However, the accurate quantification of lipid components, such as sterols, within these models remains a critical requirement for validation, data interpretation, and comparison. Here, we present a reliable and sensitive colorimetric assay using the Zak color reaction, which we have specifically adapted for the quantification of sterols at the micro-scale level. The assay was evaluated using cholesterol, ergosterol, and sitosterol standards, reflecting the diversity of sterol species across organisms. The reaction mechanism involves the dehydration of sterols to form carbonium ions, which are oxidized to form various enylic carbonium ions with specific absorption peaks. Due to the different chemical structures of cholesterol, ergosterol, and sitosterol, the resulting spectra show that the colored reaction products are formed in different proportions. The stability and interconversion of these species over time were analyzed. Cholesterol and sitosterol showed a clear peak at 555 nm, while ergosterol had prominent peaks at shorter wavelengths. Sterol assays on liposomal preparations showed accurate sterol incorporation with minimal loss during processing steps. These results demonstrate that this assay provides a robust and accurate measurement of sterol content in large unilamellar vesicles, making it a valuable tool for liposomal studies.