Pb Ca Research Articles

Zircon U–Pb CA–ID–TIMS constraints on the chronology of the Late Carboniferous–early Permian continental Döhlen Basin and its correlation with the Thuringian Forest Basin (Central and Eastern Germany)

Zircon U–Pb CA–ID–TIMS constraints on the chronology of the Late Carboniferous–early Permian continental Döhlen Basin and its correlation with the Thuringian Forest Basin (Central and Eastern Germany)

Extraordinary relative cooling power in the magnetocaloric La0.6Y0.07Ca0.33MnO3-δ

The magnetocaloric effect of La0.6Y0.07Ca0.33MnO3-δ is reported to cover a wide temperature range, including ambient temperature and cryogenic temperature, making it a promising material for magnetic refrigerators. Furthermore, the remarkable cooling power of La0.6Y0.07Ca0.33MnO3-δ is much higher than that of well-known magnetic refrigerants like Gd, (La–Sr)MnO3, (La–Sr)MnO3, (La–Ca–Pb)MnO3, and La1-xCaxMnO3 samples. La0.6Y0.07Ca0.33MnO3-δ can be used as a single magnetic refrigerant in MR at room-temperature and cryogenic temperatures. Consequently, La0.6Y0.07Ca0.33MnO3-δ is recommended as a potential magnetic refrigerant for various applications, including food refrigeration and nitrogen liquefaction.

N,N’-bis(3-dithiocarbamatopropyl) piperazine bridged metallomacrocyclic complexes of Ni(II), Cu(II) and Zn(II): Synthesis, characterization, photophysical, in-silico study and their potential utility in heavy metal ion sensing

Two secondary diamines viz. N,N’-bis{3-(p-methoxybenzylamino)propyl}piperazine (H2L1) and N,N’-bis{3-(p-chlorobenzylamino)propyl}piperazine (H2L2) holding N,N’-bispropylpiperazine linkers have been prepared and subsequently used to derive a new series of N,N’-bis(3-dithiocarbamatopropyl) piperazine bridged metallomacrocyclic complexes [M(II)2-µ2-bis-{(κ2S,S-S2CN(R)C3H6)2piperazine}] wherein R = p-methoxybenzyl, M = Ni(II) 1, Cu(II) 2, Zn(II) 3; R = p-chlorobenzyl, M = Ni(II) 4, Cu(II) 5, Zn(II) 6. The formation and purity of all the metallomacrocyclic dithiocarbamate complexes were verified by microanalysis and standard methods such as HRMS, NMR, IR and UV–Visible absorption spectroscopy and corroborated by density functional theory calculations. The experimental (magnetic susceptibility and UV–Visible) and theoretical calculations suggest a square planar/distorted square planar environment around nickel(II)/copper(II) and tetrahedral/distorted tetrahedral environment around zinc(II) centres in 1–6. Thermogravimetric study was carried out on 1–6 to study their thermal stability and degradation behaviour. Notably, TG curves of compounds 2, 3 and 5 gave a stable residual mass corresponding to corresponding metal sulphides (MS). Notably, the calculated HOMO-LUMO gaps (1.19–1.33 eV) for Cu(II)-dithiocarbamate 2 and 5 indicates their semiconducting nature. The potentials of these metallomacrocycles as a molecular probe for optical sensing of environmentally hazardous heavy metal ions ca Pb(II), Cd(II) and Hg(II) were further examined by using UV–Visible and fluorescence spectroscopies.

Study on electrochemical properties of lead calcium tin anode for hydrometallurgy

This study aims to investigate the electrochemical properties of lead calcium tin (Pb–Ca(0.14%)–Sn(1.04%)) anode employed in hydrometallurgy. Various methods were employed, including cyclic voltammetry (CV), linear sweep voltammetry (LSV), and electrochemical impedance spectroscopy (EIS), to comprehensively characterize the behavior of this alloy under diverse operating conditions. The findings of this investigation indicate that the Pb–Ca(0.14%)–Sn(1.04%) anode demonstrates remarkable corrosion resistance and a lower oxygen evolution potential in comparison to conventional lead anodes. As a result, enhanced operational efficiency can be achieved. Furthermore, the incorporation of Ca and Sn in the alloy has a substantial positive effect on its mechanical properties, thereby rendering the anode more resilient in harsh operating environments. Consequently, this contributes to reduced maintenance costs. Overall, this study underscores the promising potential of lead calcium tin anodes in promoting more sustainable and efficient hydrometallurgical processes.

Microstructure and Its Heat Treatment Process of Thin Films Fabricated by Alternate Sputtering of (Bi,Pb)2Sr2CaCu2O x and Pb–Ca–Cu–O Targets on SrTiO3 Substrates

For obtaining microscopic knowledge toward a fabrication process of (Bi,Pb) <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Sr <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Ca <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Cu <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> O <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">_x</i> (Bi,Pb-2223) single-phase material, we fabricated a multilayered film on a SrTiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> (001) substrate by a sputtering method using (Bi,Pb) <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Sr <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> CaCu <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">_y</i> (Bi,Pb-2212) and Pb–Ca–Cu–O targets alternately at 650˚C. The as-grown film was an epitaxially grown multilayered film consisting of Bi,Pb-2212 and Pb–Ca–Cu–O layers. Coarse grains of impurity phases were also formed within the multilayered film, and these impurity phases were difficult to eliminate even after heat treatments. After 10 h heat treatment at 840°C with Bi,Pb-2223 pellets, the phase transition from Bi,Pb-2212 to Bi,Pb-2223 occurred in the multilayered film. The phase transition to Bi,Pb-2223 proceeded preferentially at the interface with the impurity phases and the Pb–Ca–Cu–O layers. These observation results suggest that the impurity phases promote three-dimensional atomic diffusion in the multilayered film to accelerate the phase transition to Bi,Pb-2213, as well as consume constituent elements, Ca, Cu and O. Even after the 100 h heat treatment at 840°C with Bi,Pb-2223 pellets, the phase transition from Bi,Pb-2212 to Bi,Pb-2223 did not proceed completely, and the fraction of the Bi,Pb-2223 phase in the whole superconducting phases was ∼50%. It is suggested that controlling the formation and microstructure of the impurity phases is a key to further increasing the fraction of the Bi,Pb-2223 phase.

Effect of Cl−/Mn2+ ions on the oxygen evolution and corrosion behaviors of 3D-Pb-Ca-Sn anode for copper electrowinning

In this research, the 3D-Pb-Ca-Sn anode was fabricated and may be a promising anode for copper electrowinning. The effects of Cl− and Mn2+ ions on the oxygen evolution and corrosion behaviors of 3D-Pb-Ca-Sn anode were investigated by electrochemical methods. Besides, the phase composition, morphology and element distribution of the oxide layer were also studied. Compared with the traditional Pb–Ca–Sn alloy, 3D-Pb-Ca-Sn anode shows much lower anodic potential, oxygen evolution overpotential and cell voltage, but higher exchange current density. The oxygen evolution overpotential of 3D-Pb-Ca-Sn anode is 0.702 V at a current density of 200 A/cm2, which is 75 mV lower than that of Pb–Ca–Sn anode, suggesting potential power savings. These characteristics are mainly attributed to the increase of specific surface area. Although the presence Cl− ions deteriorate the corrosion of the anode, the stability of 3D-Pb-Ca-Sn anodic layer is enhanced by the combined action of Mn2+ ions and its excellent 3D structure.

A novel ionic liquid for improvement of lead-acid battery performance and protection of its electrodes against corrosion

A novel ionic liquid (IL) (1-octyl-3-propyl-1H-imidazole-3-ium iodide) was synthesized and used as a corrosion inhibitor for battery electrodes in 34% H2SO4 solution because IL compounds have high ionic conductivity and superior adsorption capabilities. Fourier transform infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance (1H NMR) spectroscopy were used to identify the novel IL. According to electrochemical measurements, IL molecules adsorption on the electrode surface of the battery increased the charge transfer resistance, which in turn enhanced the inhibition efficiency, which reached 91.64% in the electrochemical impedance spectroscopy (EIS) and 87.70% in the electrochemical frequency modulation (EFM) technique. The adsorption of IL molecules on the surface of the battery electrode is demonstrated by several surface morphology investigations. The battery tests were performed using Pb–Ca alloy as the working electrode. Results of the tests indicated an increase in both electrical capacity efficiencies from 84.66 to 97% and reserve capacity from 50 to 60 min. Thus, this IL compound can improve the battery performance if used as an electrolyte additive.

Use of Eggshell-Catalyzed Biochar Adsorbents for Pb Removal from Aqueous Solution.

Eggshell is a cheap and environmentally friendly calcium source. In this study, Ca-modified biochar adsorbents (CEA) were prepared by 1:10, 1:2, and 1:1 mass ratio of the eggshell and Eupatorium adenophorum. The CEA-2 sample prepared with a 1:2 mass ratio showed a maximum Pb adsorption capacity (97.74 mg·g–1) at the conditions of an initial pH of 7.0, an adsorbent dosage of 0.5 g·L–1, and a contact time of 8.0 h. The kinetic and isotherm studies indicated that the adsorption process of the CEA-2 sample had monolayer adsorption characteristics, which was controlled together by intraparticle and interface diffusion. Thermodynamic studies indicated that the adsorption process of CEA-2 was spontaneous (ΔG0 <0) and endothermic (ΔH0 > 0). X-ray diffraction and scanning electron microscopy analyses showed a uniform distribution of Ca–Pb precipitation on the CEA-2 surface, which proved that chemical precipitation was the main adsorption mechanism. Fourier transform infrared spectra found that CEA-2 had abundant active groups, especially nitrogen-containing functional groups, which could adsorb Pb through a surface complexation reaction. The Brunauer–Emmett–Teller surface area of CEA-2 was found to be 621 m2·g–1, and such developed pores could ensure the smooth diffusion of Pb. Finally, the effect of coexisting cation and anion experiment and the cyclic regeneration experiment indicated that CEA-2 had prominent stability and reusability for Pb adsorption.

Study of the production and decay properties of neutron-deficient nobelium isotopes

The new neutron-deficient isotope \(^{249}\)No was synthesized for the first time in the fusion-evaporation reaction \(^{204}\)Pb(\(^{48}\)Ca,3n)\(^{249}\)No. After separation, using the kinematic separator SHELS, the new isotope was identified with the GABRIELA detection system through genetic correlations with the known daughter and granddaughter nuclei \(^{245}\)Fm and \(^{241}\)Cf. The alpha-decay activity of \(^{249}\)No has an energy of 9129(22) keV and half-life 38.3(2.8) ms. An upper limit of 0.2% was measured for the fission branch of \(^{249}\)No. Based on the present data and recent information on the decay properties of \(^{253}\)Rf and aided by Geant4 simulations, the ground state of \(^{249}\)No is assigned the 5/2\(^+\)[622] neutron configuration and a partial decay scheme from \(^{253}\)Rf to \(^{245}\)Fm could be established. The production cross-section was found to be \(\sigma \)(3n)=0.47(4) nb at a mid-target beam energy of 225.4 MeV, which corresponds to the maximum of the calculated excitation function. Correlations of the \(^{249}\)No alpha activity with subsequent alpha decays of energy 7728(20) keV and half-life \(1.2_{-0.4}^{+1.0}\) min provided a firm measurement of the electron-capture or \(\beta ^{+}\) branch of \(^{245}\)Fm to \(^{245}\)Es. The excitation function for the 1n, 2n and 3n evaporation channels was measured. In the case of the 2n-evaporation channel \(^{250}\)No, a strong variation of the ground state and isomeric state populations as a function of bombarding energy could be evidenced.

Dysbiosis of the duodenal microbiota as a diagnostic marker for pancreaticobiliary cancer.

BACKGROUNDPancreaticobiliary cancer (PB Ca) is a lethal disease, and a useful diagnostic marker is urgently needed. A correlation between the human microbiota and malignant gastrointestinal diseases was recently reported.AIMTo investigate the efficacy of the duodenal microbiota for diagnosing PB Ca.METHODSWe recruited 22 patients with benign pancreaticobiliary diseases (benign group) and 12 patients with PB Ca (malignant group). The duodenal microbiota of each patient was analyzed by the 16S rDNA terminal restriction fragment length polymorphism method. Patient characteristics, tumor markers, and relative abundances of the duodenal microbiota were compared between the benign and malignant groups.RESULTSCancer antigen 19-9 (CA19-9), Bifidobacterium, Clostridium cluster XVIII, and Prevotella levels differed significantly between the benign and malignant groups. Clostridium cluster XVIII had the greatest area under the receiver operating characteristic curve (AUC) among the four factors with respect to diagnosing PB Ca (cutoff value: 3.038%; sensitivity: 58.3%; specificity: 95.2%; AUC: 0.81). The combination of Clostridium cluster XVIII (cutoff value: 3.038%) and CA19-9 Levels (cutoff value: 18.8 U/mL) showed 91.7% sensitivity and 71.4% specificity for diagnosing PB Ca.CONCLUSIONThe duodenal microbiota may be useful for PB Ca screening.

Two-phase late Paleozoic magmatism (~\u2009313\u2013312 and\u2009~\u2009299\u2013298\xa0Ma) in the Lusatian Block and its relation to large scale NW striking fault zones: evidence from zircon U\u2013Pb CA\u2013ID\u2013TIMS geochronology, bulk rock- and zircon chemistry

Late Paleozoic (Variscan) magmatism is widespread in Central Europe. The Lusatian Block is located in the NE Bohemian Massif and it is part of the Saxothuringian Zone of the Variscan orogen. It is bordered by two major NW-trending shear zones, the Intra-Sudetic Fault Zone towards NE and the Elbe Fault Zone towards SW. The scarce Variscan igneous rocks of the Lusatian Block are situated close to these faults. We investigated 19 samples from Variscan plutonic and volcanic rocks of the Lusatian Block, considering all petrological varieties (biotite-bearing granites from the Koenigshain and Stolpen plutons, amphibole-bearing granites from three boreholes, several volcanic dykes, and two volcanites from the intramontane Weissig basin). We applied whole-rock geochemistry (18 samples) and zircon evaporation dating (19 samples). From the evaporation data, we selected six representative samples for additional zircon SHRIMP and CA–ID–TIMS dating. For the Koenigshain pluton, possible protoliths were identified using whole-rock Nd-isotopes, and zircon Hf- and O-isotopes. The new age data allow a subdivision of Variscan igneous rocks in the Lusatian Block into two distinct magmatic episodes. The spatial relation of the two age groups to either the Elbe Fault Zone (298–299 Ma) or the Intra-Sudetic Fault Zone (312–313 Ma) together with reports on the fault-bound character of the dated intrusions suggests an interpretation as two major post-collisional faulting episodes. This assumption of two distinct magmatic periods is confirmed by a compilation of recently published zircon U–Pb CA–ID–TIMS data on further Variscan igneous rocks from the Saxothuringian Zone. New geochemical data allow us to exclude a dominant sedimentary protolith for the Koenigshain pluton as supposed by previous investigations. This conclusion is mainly based on new O- and Hf-isotope data on zircon and the scarcity of inherited zircons. Instead, acid or intermediate igneous rocks are supposed as the main source for these I-type granitoids from the Koenigshain pluton.

Extremely relative cooling power of Cu0.35Zn0.65Fe2O4

Here, it is reported that magnetocaloric effect of Cu0.35Zn0.65Fe2O4 (CZF) ferrite covers a large range of temperature as an effective material for magnetic refrigerator (MR). In addition, the relative cooling power (RCP) in CZF ferrite is significantly larger than corresponding values of the famous magnetic refrigerants such as Gd, MnAs1−xSbx, Gd5Si2Ge2, (La–Sr)MnO3, (Pr–Sr)MnO3, (La–Sr)MnO3, (La–Ca–Pb)MnO3, and (La–Ca–Sr)MnO3. Therefore, CZF ferrite is useful to be a working substance in MR as a single magnetic refrigerant, including room temperature and very low temperatures.

Characterization of “Sandwich” Wulfenite from the Ojuela Mine, Mapimí, Mapimí Municipality, Durango, Mexico: Evidence of Preferred Secondary Nucleation on Selected Wulfenite Faces

This paper describes the formation of “sandwich” wulfenite. Banded wulfenite from the Ojuela Mine, Mapimí, Durango, Mexico, have been found since 2017, but an explanation for the band formation has not been provided. X-ray diffraction (XRD) showed the wulfenite to have a tetragonal unit cell of a = 5.4374(1), c = 12.1123(7) Å. The Raman spectrum was dominated by ν1 (Ag) around 870 cm–1, while the weak shoulder at 859 cm–1 represents the strain activated ν1 (Bu) infrared (IR) band. Two ν2 modes were observed at 318 cm–1 (Ag) and 351 cm–1 (Bg). For the ν3(Eg), the band at 768 cm–1 was assigned to the Bg symmetric mode and the 745 cm–1 band to the Eg vibration. The IR spectrum showed two strong bands at 835 and 779 cm–1 corresponding to v3 modes and a very weak one at 496 cm–1. SEM-EDX (scanning electron microscopy – energy dispersive X-ray analysis) showed that the band does not extend into the main crystal but is limited to the surface as secondary growth. The main thick tabular crystal was dominated by {001}, {110}, and {111}. The {001} surfaces of the wulfenite crystals showed evidence of later dissolution, which may have been part of the source material for this secondary crystallization. The chemical composition of the main wulfenite crystal proved only minor substitution of W for Mo. Contrastingly, a much higher number of substitutions by V, As, and W for Mo – as well as Ca, Fe, Zn, Cu, and Al for Pb – was observed in the secondary band, indicating a change in the fluid composition from which the band crystallized compared to the original wulfenite. Changes in lattice parameters of the secondary wulfenite crystals and the energy involved in nucleation on the surface of the original wulfenite as well as the different bonds exposed on different faces favored the formation of the band on only {110}.

Electrochemical properties of Ca–Pb electrode for calcium-based liquid metal batteries

The Ca–Pb electrode couple is considered to be one of the least expensive (∼36 $/(kW h)) among various optional materials for liquid–metal batteries (LMBs). The electrochemical properties of Ca–Pb alloy in a Ca∣LiCl–NaCl–CaCl2∣Pb cell were investigated in this paper. The electrode potential maintained a linear relationship in the current density range of 50–200 mA cm-2, which indicates that the alloying and dealloying processes of Ca with Pb attained rapid charge transfer and mass transport in the interface between the liquid electrode and electrolyte. The Ca–Pb electrode exhibited remarkable properties with a high discharge voltage of 0.6 V, a small self-discharge current density ( 98.84%). The postmortem analysis showed that intermetallics CaPb3 and CaPb were uniformly distributed in the electrode with different molar fractions of Ca, which indicates that the nucleation of solid intermetallics did not hinder the diffusion of Ca in the electrode. This investigation on Ca–Pb electrode sheds light on the further research and the design of electrodes for Ca-based LMBs.

Solution Thermodynamics and Aseotropic Mixtures in the Melts of Lead–Calcium System

The partial and integral thermodynamic functions of mixing and evaporation for the melts of Pb–Ca system have been calculated from the vapor pressure data determined by boiling point method with involvement of published data. The formation of alloys containing 66.67 at % Ca and leads to ordering in the system. Melting enthalpy of Ca2Pb of 13 ± 1.6 kJ/mol was found from the difference in sublimation and evaporation enthalpies. Based on the data on vapor pressure for the components, Pb–Ca constitution diagram has been supplemented by the fields of liquid and vapor coexistence under atmospheric pressure and vacuum of 1.33 and 0.7 kPa. The existence of two azeotropic mixtures with calcium concentration of 37.6 and 81.3 at % and boiling points of 2217 and 1635°C (2490 and 1908 K), respectively, has been revealed. When pressure (boiling point) decreases, the composition of azeotropic mixtures change according to Vrevskii laws. The position of field borders of vapor–liquid equilibrium indicates the impossibility of separation of Pb–Ca system into metals by distillation.

Correlation between lead speciation and inhalation bioaccessibility using two different simulated lung fluids

This study investigated the relationship between lead (Pb) speciation determined using Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy in <10 μm particulate matter (PM10) from mining/smelting impacted Australian soils (PP, BHK5, BHK6, BHK10 and BHK11) and inhalation exposure using two simulated lung fluids [Hatch’s solution, pH 7.4 and artificial lysosomal fluid (ALF), pH 4.5]. Additionally, elemental composition of Pb rich regions in PP PM10 and the post-bioaccessibility assay residuals were assessed using a combination of Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDX) to provide insights into how extraction using simulated lung fluids may influence Pb speciation in vitro. Correlation between Pb speciation (weighted %) and bioaccessibility (%) was assessed using Pearson r (α = 0.1 and 0.05). Lead concentration in PM10 samples ranged from 782 mg/kg (BHK6) to 7796 mg/kg (PP). Results of EXAFS analysis revealed that PP PM10 was dominated by Pb adsorbed onto clay/oxide, while the four BHK PM10 samples showed variability in the weighted % of Pb adsorbed onto clay/oxide and organic matter bound Pb, Pb phosphate, anglesite and galena. When bioaccessibility was assessed using different in vitro inhalation assays, results varied between samples and between assays, Pb bioaccessibility in Hatch’s solution ranged from 24.4 to 48.4%, while in ALF, values were significantly higher (72.9–96.3%; p < 0.05). When using Hatch’s solution, bioaccessibility outcomes positively correlated to anglesite (r:0.6246, p:0.0361) and negatively correlated to Pb phosphate (r: -0.9610, p:0.0041), organic bound Pb (r: -0.7079, p: 0.0578), Pb phosphate + galena + plumbojarosite (r: -0.9350, p: 0.0099). No correlation was observed between Pb bioaccessibility (%) using Hatch’s solution and weighted % of Pb adsorbed onto clay/oxide and between bioaccessibility (%) using ALF and any Pb species. SEM and EDX analysis revealed that a layer of O–Pb–Ca–P–Si–Al–Fe formed during the in vitro extraction using Hatch’s solution.

Impact of orthophosphate on lead release from pipe scale in high pH, low alkalinity water

This study explored the ability of orthophosphate addition to limit lead release from lead service lines delivering high pH, low alkalinity water. We built pipe loop reactors with lead pipes harvested from Providence, RI, and we operated them with high pH and low alkalinity water of a composition similar to that in Providence. Orthophosphate addition decreased the release of both dissolved and particulate lead to the water. The most substantial decreases in total lead concentrations occurred after 15 weeks of orthophosphate addition, which was associated with the formation of calcium-lead-phosphorus (Ca–Pb–P) solids as part of the pipe scale. Pre-existing hydrocerussite (Pb3(CO3)2(OH)2(s)) in the scale of the lead pipe appeared to promote the formation of a Ca–Pb–P solid similar to phosphohedyphane (Ca2Pb3(PO4)3(Cl,F,OH)(s)). Continuous orthophosphate addition was also associated with the formation of a calcium phosphate solid with features like those of fluorapatite (Ca5(PO4)3F(s)) on the outermost layer of the scale. Through promoting the formation of these new solids within and on top of the scales, orthophosphate addition limited release of dissolved and particulate lead. These results demonstrate the ability of orthophosphate to control lead release at higher pH conditions than those for which it has typically been used. In addition to the formation of phosphate solids, PbO2(s), which was not present on the as-received pipes, was formed due to the constant supply of free chlorine in the laboratory-scale experiment.

Thermodynamic properties of Ca–Pb electrodes determined by electromotive force measurements

Thermodynamic properties of Ca–Pb alloys are investigated by electromotive force (emf) measurements to determine equilibrium cell potentials and phase properties for their application in energy storage systems such as liquid metal batteries. Using the electrochemical cell Ca(s) | CaF2(s) | Ca(in Pb) at 700–1060 K, cell emf is measured for thirteen Ca–Pb alloys at mole fractions, xCa = 0.06–0.80. At 873 K, the equilibrium potentials of liquid Ca–Pb alloys are 0.57–0.62 V versus Ca and the activity values are as low as aCa = 6.2 × 10−8 at xCa = 0.06. In addition, the emf values as a function of temperature provide partial molar quantities (entropy and enthalpy) as well as phase transitions which are corroborated by determining transition temperatures and phase constituents using differential scanning calorimetry (DSC) and powder X-ray diffraction (XRD). This work establishes the fundamental data necessary for the design of Pb-containing liquid metal electrodes through the integration of electrochemical, thermal, and structural properties of Ca–Pb electrodes.

High-precision U–Pb CA–ID–TIMS dating and chronostratigraphy of the dinosaur-rich Horseshoe Canyon Formation (Upper Cretaceous, Campanian–Maastrichtian), Red Deer River valley, Alberta, Canada

The non-marine Horseshoe Canyon Formation (HCFm, southern Alberta) yields taxonomically diverse, late Campanian to middle Maastrichtian dinosaur assemblages that play a central role in documenting dinosaur evolution, paleoecology, and paleobiogeography leading up to the end-Cretaceous extinction. Here, we present high-precision U–Pb CA–ID–TIMS ages and the first calibrated chronostratigraphy for the HCFm using zircon grains from (1) four HCFm bentonites distributed through 129 m of section, (2) one bentonite from the underlying Bearpaw Formation, and (3) a bentonite from the overlying Battle Formation that we dated previously. In its type area, the HCFm ranges in age from 73.1–68.0 Ma. Significant paleoenvironmental and climatic changes are recorded in the formation, including (1) a transition from a warm-and-wet deltaic setting to a cooler, seasonally wet-dry coastal plain at 71.5 Ma, (2) maximum transgression of the Drumheller Marine Tongue at 70.896 ± 0.048 Ma, and (3) transition to a warm-wet alluvial plain at 69.6 Ma. The HCFm’s three mega-herbivore dinosaur assemblage zones track these changes and are calibrated as follows: Edmontosaurus regalis – Pachyrhinosaurus canadensis zone, 73.1–71.5 Ma; Hypacrosaurus altispinus – Saurolophus osborni zone, 71.5–69.6 Ma; and Eotriceratops xerinsularis zone, 69.6–68.2 Ma. The Albertosaurus Bonebed — a monodominant assemblage of tyrannosaurids in the Tolman Member — is assessed an age of 70.1 Ma. The unusual triceratopsin, Eotriceratops xerinsularis, from the Carbon Member, is assessed an age of 68.8 Ma. This chronostratigraphy is useful for refining correlations with dinosaur-bearing upper Campanian–middle Maastrichtian units in Alberta and elsewhere in North America.

First high-precision U–Pb CA–ID–TIMS age for the Battle Formation (Upper Cretaceous), Red Deer River valley, Alberta, Canada: implications for ages, correlations, and dinosaur biostratigraphy of the Scollard, Frenchman, and Hell Creek formations

The Battle Formation (BFm) is a widespread Upper Cretaceous marker horizon in western Canada that records a time of low sediment input and marks the boundary between the Edmontonian and Lancian land-vertebrate ages. Here, we present the first high-precision U–Pb CA–ID–TIMS age of 66.936 ± 0.047/0.060/0.140 Ma for the Battle bentonite, an altered vitric ash in the upper portion of the BFm at Knudsen’s Farm in the Red Deer River valley of Alberta. This age supersedes those previously reported, confirms that rates of sediment accumulation for the formation were very low (∼1.40 cm/ka), and allows us to interpolate an age range of ∼66.88–67.20 Ma for the BFm. Our data also provide a maximum age of ∼66.88 Ma for the base of the overlying Scollard Formation, a dinosaur-rich unit. We combine our age data with calibrated magneto- and palynostratigraphic data to assess chronostratigraphic correlations among the Scollard Formation of Alberta, the Frenchman Formation of Saskatchewan, and the Hell Creek Formation in eastern Montana. Whereas the combined data support previous interpretations that equate the age ranges of the Scollard Formation, Frenchman Formation, and the upper one third of the Hell Creek Formation in eastern Montana, they also indicate that all of the lower one third (L3) and part of the middle one third (M3) of the Hell Creek Formation in Montana are chronostratigraphically equivalent to all or part of the sub-BFm unconformity and the BFm in Alberta. Accordingly, a minimum age of ∼67.20 Ma is assessed for the base of the Hell Creek Formation in its type area.