Favorable Sites Research Articles

A First‐Principles Investigation of Monolayer MoS2 Doped with Mn and V as an Excellent NO2 Sensor with High Selectivity

This article conducts a comprehensive investigation into the adsorption properties of both pristine MoS2 monolayers and those doped with Mn and V, wherein these dopants replace Mo atoms. By the first‐principles calculations, the research reveals a noteworthy reduction in the adsorption energy of NO2 on Mn‐doped and V‐doped MoS2 monolayers compared to pure MoS2 monolayers. Specifically, at the most favorable adsorption site, the adsorption energy decreases from −5.83 to 5.908 eV for Mn‐doped MoS2 and from −5.58 to −6.17 eV for V‐doped MoS2. Furthermore, computations of the band structure, work function, and charge density difference highlight a significant degree of charge transfer and coexistence of electrons within these systems. Additionally, post‐adsorption of NO2 molecules, a distinct shift in the density of states (DOS) toward lower energy states is observed at the adsorption sites of both MoS2/Mn and MoS2/V monolayers, underscoring their exceptional sensitivity in detecting NO2. In summary, these results demonstrate the substantial potential of Mn‐doped and V‐doped MoS2 monolayers as highly sensitive materials for NO2 detection. Their lower adsorption energies and noteworthy shifts in DOS following NO2 adsorption enhance their capabilities as NO2 sensors.

Management and outcomes of children with rhabdomyosarcoma in a low-to-middle-income country: A first report from Chris Hani Baragwanath Academic Hospital, South Africa

BackgroundStudies done in South Africa show that Rhabdomyosarcomas (RMS) comprises 6 % of childhood malignancies. Very few centres in South Africa (SA) have reported their management and outcomes of children with RMS, and as such, it is difficult to compare outcomes and come up with management protocols befitting our environment. AimTo describe the management and outcomes of children with RMS at Chris Hani Baragwanath Academic Hospital (CHBAH). SettingThe Departments of Paediatric Surgery and Paediatric Oncology. MethodsA retrospective review of clinical records of patients below 18 years of age with RMS, managed from 01 January 2008 to 31 December 2017. ResultsFifty-eight patients had RMS, 77 % embryonal and 21 % alveolar subtypes. Primary tumour site was favourable in 48 %, and unfavourable in 45 %. Thirty-three patients (57%,) had surgery for the primary tumour, whilst 25 patients (43 %) did not have surgery. Post-operative clinical groups were 29 % group I, 9 % group II, 43 % group III, and 19 % group IV. The overall 5-year survival was 55%. Predictors for a good outcome included early disease stage at presentation, favourable site, embryonal subtype, and surgery for the primary tumour. ConclusionThe 5-year survival of 55 % from this study is low when compared to high income countries but is comparable to middle income countries. The main factor contributing to mortality is patients presenting with unresectable advanced disease in unfavourable sites. Surgical resection plays a major role in improving outcomes. Level of evidenceIV

Designing activated carbon and porous carbon nanofibers for insight into their differences in adsorption affinity mechanisms of VOCs

The adsorption technology has been considered as an effective and economical strategy to control volatile organic compounds (VOCs) through various types of porous materials. As two potential porous materials, activated carbon and carbon nanofibers were synthesized as VOCs adsorbents. In order to investigate the difference in the adsorption of VOCs between activated carbon and carbon nanofibers, the specific surface area, pore structure and chemical functional groups of VOCs adsorbent were analyzed. In particular, the carbon nanofibers (CNF) activated at 800 ℃ showed an excellent specific surface area (2524 m2·g−1), abundant pores (1.66 mL·g−1), and rich functional groups (N: 8.29 at%). Meanwhile, the carbon nanofibers had a better adsorption performance for acetone (1069.82 mg·g−1) and toluene (427.72 mg·g−1) than activated carbon materials. Furthermore, the theoretical calculations were conducted to reveal the mechanism of favorable adsorption on the CNFs. The theoretical adsorption energies of CNF are −31.9 kJ·mol−1 (acetone) and −67.5 kJ·mol−1 (toluene), respectively, which have more favorable adsorption sites and stronger charge redistribution than activated carbon. This research guided the approach to obtain the porous carbon nanofibers and provided the evidence for CNFs (curved carbon) exhibiting a better adsorption ability to VOCs.

Identifying the Stripping of Oxide Debris from Graphene Oxide: Evidence from Experimental Analysis and Molecular Simulation.

In this study, characteristics of oxidation debris (OD) and its stripping mechanism from graphene oxide (GO) were explored. The results demonstrated that OD contains three components, namely, protein-, fulvic acid-, and humic acid-like substances; among these, protein-like substances with lower molecular weight and higher hydrophilicity were most liable to be stripped from GO and were the primary components stripped from GO at pH < 10, whereas humic acid- and fulvic acid-like substances were stripped from GO at pH > 10. During the stripping of OD, hydrogen bonds from carboxyl and carbonyl were the first to break, followed by hydrogen bonds from epoxy. Subsequently, π-π interactions were broken, and hydrogen bond interactions induced by hydroxyl groups were the hardest to break. After the stripping of OD, the recombination of OD on GO was observed, and regions containing relatively fewer oxygen-containing functional groups were favorable binding sites for the readsorbed OD. The stripping and recombination of OD on GO resulted in an uneven GO surface, which should be considered during the development of GO-based environmental materials and the evaluation of their environmental behavior.

Effect of Metal Carbides on Hydrogen Embrittlement: A Density Functional Theory Study

This study uses plane wave density functional theory (DFT) to investigate the effect of certain metal carbides (Niobium carbide, Vanadium carbide, Titanium carbide, and Manganese sulfide) on hydrogen embrittlement in pipeline steels. Our results predict that the interaction of hydrogen molecules with these metal carbides occurs in the long range with binding energy varying in the energy window [0.043 eV to 0.70 eV].In addition, our study shows the desorption of H2 molecules from these metal carbides in the chemisorptions. Since atomic state hydrogen interacts with NbC, VC, TiC, and MnS to cause embrittlement, we classified the strength of the hydrogen trapping as TiC + H &gt; VC + H &gt; NbC + H&gt; MnS + H. In addition, our study reveals that the carbon site is a more favorable hydrogen-trapping site than the metal one.

Plasmon assisted synthesis of TiN-supported single-atom nickel catalysts

We report the deposition of single atom nickel catalyst on refractory plasmonic titanium nitride (TiN) nanomaterials supports using the wet synthesis method under visible light irradiation. TiN nanoparticles efficiently absorb visible light to generate photoexcited electrons and holes. Photoexcited electrons reduce nickel precursor to deposit Ni atoms on TiN nanoparticles’ surface. The generated hot holes are scavenged by the methanol. We studied the Ni deposition on TiN nanoparticles by varying light intensity, light exposure time, and metal precursor concentration. These studies confirmed the photodeposition method is driven by hot electrons and helped us to find optimum synthesis conditions for single atoms deposition. We characterized the nanocatalysts using high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), energy dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS). We used density functional theory (DFT) calculations to predict favorable deposition sites and aggregation energy of Ni atoms on TiN. Surface defect sites of TiN are most favorable for single nickel atoms depositions. Interestingly, the oxygen sites on native surface oxide layer of TiN also exhibit strong binding with the single Ni atoms. Plasmon enhanced synthesis method can facilitate photodeposition of single atom catalysts on a wide class of metallic supports with plasmonic properties.

High-temperature Mo-based metallic glass thin films with tunable microstructure and mechanical behaviors

Developing high-temperature metallic glass thin films (MGTFs) with excellent combination properties is crucial for extending the practical applications of metallic glasses. A high-temperature multicomponent Mo-based MGTF with tunable microstructure prepared by single-target magnetron sputtering was presented in this study. Corresponding mechanical behaviors and thermal stability of MGTFs related to microstructure are systemically explored. By adjusting deposition parameters (pressure and power), the microstructure of as-deposited MGTFs can be altered from the dense homogeneous type to the loose nanoglass type. Such structure evolution can be explained by the competition between the surface diffusion and geometric shadowing effect. MGTFs with dense microstructure possess smaller surface roughness, higher hardness, higher Young’s modulus, and better wear resistance. Moreover, they also possess higher thermal stability where the fully amorphous structure and smooth surface can be well maintained after vacuum annealing at 1123 K for 30 min. By contrast, the MGTF with nanoglass microstructure shows inferior mechanical properties and thermal stability due to plentiful loose interface regions, providing abundant free volumes during deformation and acting as favorable crystal nucleation sites during annealing. The correlation between the microstructure and properties of as-deposited MGTFs is clarified with the universal scaling law of glasses. The annealing treatment distinctly increases the hardness and Young’s modulus of MGTFs. Meanwhile, after annealing, pop-in behaviors occur in the as-annealed MGTFs with dense microstructure but not in the as-annealed MGTF with nanoglass microstructure during the nanoindentation. These phenomena can be rationalized by the annihilation of free volumes during annealing and the evolution of the dynamical variable, shear transition zone, for the plastic deformation in MGTFs.

Microalgae derived honeycomb structured mesoporous diatom biosilica for adsorption of malachite green: Process optimization and modeling

The present study investigated the removal of malachite green dye from aquifers by means of microalgae-derived mesoporous diatom biosilica. The various process variables (dye concentration, pH, and adsorbent dose) influencing the removal of the dye were optimized and their interactive effects on the removal efficiency were explored by response surface methodology. The pH of the solution (pH = 5.26) was found to be the most dominating among other tested variables. The Langmuir isotherm (R2 = 0.995) best fitted the equilibrium adsorption data with an adsorption capacity of 40.7 mg/g at 323 K and pseudo-second-order model (R2 = 0.983) best elucidated the rate of dye removal (10.6 mg/g). The underlying mechanism of adsorption was investigated by Weber-Morris and Boyd models and results revealed that the film diffusion governed the overall adsorption process. The theoretical investigations on the dye structure using DFT-based chemical reactivity descriptors indicated that malachite green cations are electrophilic, reactive and possess the ability to accept electrons, and are strongly adsorbed on the surface of diatom biosilica. Also, the Fukui function analysis proposed the favorable adsorption sites available on the adsorbent surface.

System shift in rice: Processes and pathways of change in rice-based production systems of Southeast Asia

CONTEXTPredicting future production trends and associated land use and management practices requires an understanding of past changes in productivity and of pathways of evolving system configurations. We argue that rice systems' evolution reflects a process of adaptation to changing availabilities of production resources and the adoption of technological innovations and that differs by marginality/favorability of sites. Understanding past change trends and their determinants can help avoiding undesirable future developments and guide policy decisions for a sustained supply of rice. OBJECTIVEWe aimed to assess agronomic system change and practices, to quantify pathways of change and to identify likely drivers of but also possible risks or opportunities associated with observed patterns of agronomic system transformation in six representative lowland rice production environments in Asia. METHODSWe implemented a diachronic analysis (years 2000 vs. 2018) of rice production practices and yield attributes in 1024 households. We documented changes between 2000 and 2018 in lowland rice-based systems in six rice-growing environments in the Philippines, Myanmar and Cambodia, differentiating marginal and favorable sites in irrigated and in rainfed environments. RESULTS AND CONCLUSIONFarmers' household attributes, resource endowment, rice yields, and key constraints differed among sites. We observed relatively low annual yield in marginal (2.2–3.0 t/ ha) than favorable (3.3–8.9 t/ ha) sites depending on countries and seasons. The farmers adopted intensification related agronomic practices has increased significantly between 2000 and 2018, especially in dry season (i.e., improved seeds by 28%, mechanical tillage by 52%, direct seeding by 21%, combined harvester by 62%). The marginality of climatic and edaphic conditions, the systems' evolutionary state in 2000, and differential pressures (policy environment), opportunities (technological change) and household attributes (resource endowment) determined the observed transition pathways across study sites. SIGNIFICANCEThe trends towards maximizing land use intensity (double or multiple cropping), converging in the emergence of high-input and highly mechanized (laborsaving) in irrigated, and diversified rotations in rainfed rice production systems may help to elucidate agricultural research needs and potentially predict the requirements for future sustainable intensification of rice-based systems. Additionally, we argue for a continued need for further mechanization of rice establishment, especially shifting from transplanting to direct seeding during dry and wet seasons, and of the rice harvest, especially during wet season under fully irrigated environments.

Adsorption and reversible detection of toxic halogens gases at room temperature by two-dimensional Al2SSe for occupational sustainability

Current treatment for inhalational halogens poisoning involves providing supportive care, which includes administering humidified oxygen and managing the airway. Since toxic effects of halogens cannot be reversed, sensors with high sensitivity and good reversibility for detecting the relatively lower concentration yet noxious halogens becomes particularly significant and enticing. Herein, the structural and optoelectronic properties of toxic F2 and Cl2 gas molecules adsorbed on highly stable Al2SSe monolayer have been systematically studied by means of first-principles calculations based on density functional theory (DFT). Favorable adsorption sites of said molecules on Al2SSe were carefully examined. The relatively high, negative adsorption energy for F2 and Cl2 indicate that the adsorption process is exothermic and the molecules could be stably adsorbed on Al2SSe monolayer. This characteristic, combined with the substantial charge transfer (0.15–0.55 |e|), drastic change in work function, complete reversibility due to recovery time in 10−1 s scale and distinct optical response, render Al2SSe monolayer a viable option for utilization as either surface work functions transistor or optical chemical resistor for detecting these gases. Pearson correlation coefficient (PCC) analysis of theoretical recovery time and response value indicates that band gap change and electron transfer are the primary influencing factors. Selectivity analysis reveals that common compound forms of halogens and atmospheric molecules such as HF, HCl, N2, O2, H2 and H2O are either physically adsorbed or inert with extremely low adsorption energies on Al2SSe, prompting high F2 and Cl2 selectivity. These outcomes acclaim the exciting prospects of developing Al2SSe monolayer for specific, occupational related ultrahigh-sensitivity F2 and Cl2 sensing nanodevices.

Design of atomically localized magnetic moment by adatoms chemisorbed on graphene

Recent studies have identified that boron adatom chemisorbs on graphene with a weak localized magnetic moment. Using hybrid exchange-correlation functional, we show that P adatom rather than As can also chemically adsorb on the bridge site (Bri) of graphene. However, due to the large local distortion caused by P adsorption, the most energetically favorable site is Hollow (H) site instead with physisorption. Tensile strain (ε) is able to counterbalance the dominant distortion and can switch the stable site from H to Bri when ε exceeds 2.3 %. The corresponding localized magnetic moment is sizable with 1.00 µB, which seems stronger than the case of B adatom. Such apparent spin-polarization stems from the abundant charge transfer from P adatom to graphene. We also find that interlayer coupling of graphene can reduce the threshold of tensile strain significantly. Our findings might extend the atomic scale magnetism on graphene from hydrogen/boron to underlying phosphorus.

Prolonged exhumation and preservation of the Yuku molybdenum ore field, East Qinling, China: Constraints from medium- to low-temperature thermochronology

Molybdenum (Mo) is an important globally strategic metal and mostly occurs as molybdenite (MoS2) in diverse Mo deposits. The Yuku ore field includes multiple porphyry-skarn Mo deposits and forms a significant world-class Mo cluster in the Qinling molybdenum belt, central China. Previous studies on the ore field were largely related to its genesis, and did not highlight the post-mineralization modifications that are important to formulate prospecting strategies. The exhumation and preservation processes of the ore field through multiple tectonic events also remain poorly understood. Here, we conducted multi-method apatite U-Pb, fission-track and (U-Th)/He and zircon (U-Th)/He medium- to low-temperature thermochronology and related thermal history modelling on granitoids from the ore-hosting Shibaogou and Yuku plutons in the Yuku ore field, and integrated published studies to unravel the post-mineralization exhumation and preservation of Mo deposits. The newly determined apatite U-Pb (158.3–104.9 Ma), zircon (U-Th)/He (158.2–115.0 Ma), apatite fission-track (90.8–63.1 Ma), and apatite (U-Th)/He (67.8–35.3 Ma) ages in this study document multiple cooling pulses during post-magma emplacement. The low-temperature thermochronological ages of 158.2–35.3 Ma also record the post-mineralization cooling and exhumation history. The thermal history modelling indicates an Early Cretaceous (132–125 Ma) rapid cooling pulse, two enhanced (or accelerated) cooling pulses at ca. 125–59 Ma and post-10 Ma, together with a slow cooling or reheating pulse at ca. 59–10 Ma in the Yuku ore field. The Early Cretaceous rapid cooling is related to the coeval collisional tectonics of the East Qinling Orogen. The enhanced cooling at ca. 125–59 Ma is triggered by the post-collisional assembly of the North China and Yangtze Blocks, the subduction of Paleo-Pacific Plate, and the sinistral strike-slip motion of the nearby Tan-Lu Fault Zone. The slow cooling during ca. 59–10 Ma and the post-10 Ma enhanced cooling are correlated with the extensional tectonics derived by the subduction of Pacific Plate and the far-field effects from India-Eurasia collision. The Yuku area underwent lower exhumation in comparison to the nearby Shibaoguo and Huangbeiling areas in the Yuku ore field, which thus is helpful to the preservation of Mo deposits. The un-exhumated areas within 1.0 km at the inner and outer contact zones between the Yuku pluton and its wall rocks are postulated to be favorable sites for Mo prospecting. In addition, the un-exhumated areas surrounding other Late Mesozoic plutons in the Luanchuan region are also suggested to have high potential for Mo exploration.

Elucidating the dual effect of vanadium microalloying on hot deformation behavior of high nitrogen martensitic stainless steel

Precipitates always have a complex effect on the hot work hardening and recrystallization softening of materials. In this work, the dual effect of V-microalloying on hot deformation behavior and microstructure evolution of high nitrogen martensitic stainless steel (HNMSS) was investigated by hot compression experiments, modeling study and microstructure characterization. The results showed that V-microalloying enhanced the flow stresses and activation energy of 0.2V steel due to the fine grain strengthening effect and the blocking effect of dynamic precipitation on dislocation movement and grain boundary migration. On the other hand, the recrystallization model and deformed microstructure indicated the more intense dynamic recrystallization (DRX) softening effect in 0.2V steel, inducing the faster decrease of flow stress after the peak stress. V-microalloying promoted the dynamic precipitation of HNMSS during hot deformation, which reduced the size and increased the number of precipitates in 0.2V steel. The fine precipitates hindered dislocation movement, promoted dislocation accumulation and entanglement, formed a particle deformation zone (PDZ) with high dislocation density and large orientation gradient, and then induced the occurrence of particle-stimulated nucleation (PSN). In addition, the dislocation cells evolved from dislocation entanglement were also favorable nucleation sites for DRX.

Biodegradable and 3D printable lysine functionalized polycaprolactone scaffolds for tissue engineering applications

Tissue engineering (TE) has sparked interest in creating scaffolds with customizable properties and functional bioactive sites. However, due to limitations in medical practices and manufacturing technologies, it is challenging to replicate complex porous frameworks with appropriate architectures and bioactivity in vitro. To address these challenges, herein, we present a green approach that involves the amino acid (l-lysine) initiated polymerization of ɛ-caprolactone (CL) to produce modified polycaprolactone (PCL) with favorable active sites for TE applications. Further, to better understand the effect of morphology and porosity on cell attachment and proliferation, scaffolds of different geometries with uniform and interconnected pores are designed and fabricated, and their properties are evaluated in comparison with commercial PCL. The scaffold morphology and complex internal micro-architecture are imaged by micro-computed tomography (micro-CT), revealing pore size in the range of ~300–900 μm and porosity ranging from 30 to 70 %, while based on the geometry of scaffolds the compressive strength varied from 143 ± 19 to 214 ± 10 MPa. Additionally, the degradation profiles of fabricated scaffolds are found to be influenced by both the chemical nature and product design, where Lys-PCL-based scaffolds with better porosity and lower crystallinity degraded faster than commercial PCL scaffolds. According to in vitro studies, Lys-PCL scaffolds have produced an environment that is better for cell adhesion and proliferation. Moreover, the scaffold design affects the way cells interact; Lys-PCL with zigzag geometry has demonstrated superior in vitro vitality (>90 %) and proliferation in comparison to other designs. This study emphasizes the importance of enhancing bioactivity while meeting morphology and porosity requirements in the design of scaffolds for tissue engineering applications.

Epigenetic karst in carbonate buried hills and its influence on reservoir development: A case study of the Carboniferous Weixi’nan Sag, Beibuwan Basin, China

Karst is widely researched in the field of carbonate reservoirs. This study proposes a new formation mechanism and development model, specifically epigenetic karst, and asserts that high-quality reservoirs can be developed in the karst highlands and karst slopes of ancient landforms under the epigenetic karst with facies-controlled characteristics. The results indicate that there are three stages of karst in the study area. The first period is syngenetic karst, characterized by molds, intragranular dissolution pores, and micritization. Isotopic data reveal that the range of variation of carbonate rock 13C and 18O is similar to that of cement. The second period is epigenetic karst, the most significant karst in the study area. It undergoes a prolonged development time and features non-selective fabric dissolution. Oxygen and carbon isotopes exhibit negative values (18O ranges from −10.033‰ to −13.767‰ and 13C ranges from −2.56‰ to −0.52‰), which are significantly altered by atmospheric precipitation. The third period is buried karst, characterized by suture structure and asphaltene filling. The negative value of 18O in calcite veins is significantly &lt;−15‰. The dissolved pores and caves formed by the epigenetic karst become the primary reservoir space for oil and gas in carbonate rocks. These exhibit facies-control characteristics, indicating that bioclastic limestone karst is well-developed and micritic limestone karst is underdeveloped. The study establishes a development model for karst reservoirs in the study area, selecting the highlands and slopes of ancient landforms as favorable exploration sites.

Spin Coupling in the Initial Stages of the Zinc‐Blende MnN Growth on the CrN (111) Surface

AbstractSpin‐polarized first‐principles calculations are carried out to study the structural, electronic, and magnetic properties of the MnN growth on the CrN (111) surface. Different magnetic configurations between Mn‐deposited atoms and the substrate are considered. The H3 site is the most favorable site for the adoption and incorporation cases and the Mn spins switch from paramagnetic to antiferromagnetic arrangement. The minimum energy pathway for the Mn diffusion is calculated, showing magnetic modifications in the substrate. A structural transition from tetragonal rock‐salt to zinc‐blende (ZB) structure as the number of MnN deposited layers increases is noticed. Thermodynamic analysis demonstrates that the growth of MnN on CrN is feasible. The density of states for an MnN layer with an extra nitrogen layer shows a half‐metallic behavior and the remaining structures exhibit a metallic character. The ZB‐MnN structures have an antiferromagnetic behavior with a metallic character. Magnetic anisotropy energies reveal a switching of easy magnetization axis, from in‐plane to out‐of‐plane with the formation of MnN on the surface. These results suggest that the CrN/ZB‐MnN system may be employed in antiferromagnetic spintronics applications as the fabrication of perpendicular magnetic tunnel junctions.

Unusual, human-mediated prevalence of epiphytes in semi-arid New South Wales, Australia

Context Epiphytes are typically associated with wet forests and are seldom documented in drylands. This absence is presumed to reflect moisture limitations to their establishment and survival. Aims In response to a large body of epiphyte observations made by a pastoralist in collaboration with local Indigenous people, we investigated and documented an unusually high concentration of woody epiphytes from semi-arid eastern Australia and describe this in relation to ecological and cultural factors. Methods We searched for, recorded and measured epiphytic trees and shrubs in semi-arid eucalypt woodlands of northern New South Wales and southern Queensland. Factors influencing their distribution were examined. Key results Eucalypts growing along the Barwon River palaeochannels host 21 species of shrubs and trees. Over 95% of the 712 woody epiphytes documented were alive, and some appeared decades old; 70% were growing in trees that had been modified by humans, and at least half of the host sites were directly anthropogenically created. Epiphytes are widely, but typically sparsely, distributed in other semi-arid eucalypt woodlands, with a further 311 found during regional surveys. Conclusions The large trees of the Barwon palaeochannels, their extensive human modification to create favourable sites for epiphyte establishment, and the diversity of understorey shrubs providing a propagule source have combined to create this epiphyte-rich woodland. Their association with Culturally Modified Trees and the relatively low density of epiphytes elsewhere suggest that Aboriginal people have played a direct role in creating this landscape, to which they remain deeply connected. Implications Epiphytes may be more widespread in drylands than previously recognised. We hope that this study stimulates further research on their distribution, characteristics, and ecological and cultural associations.

Talus rock glaciers in the Cairngorm Mountains

ABSTRACT Although several relict talus rock glaciers (TRGs) of Lateglacial age have been identified in the British Isles, all have been refuted by some authors and their absence attributed to the lack of permafrost. The evidence provided by palaeoclimatic reconstructions and periglacial features, however, implies that Lateglacial permafrost was present throughout Scotland during the Loch Lomond Stade (LLS; ∼12.9–11.7 ka). Across much of the Scottish Highlands, the absence of Lateglacial TRGs is attributable to occupation of potential sites by glaciers during the LLS. In the Cairngorms, however, where limited snowfall at that time left some corries glacier-free, there is convincing evidence for TRG formation. Three examples illustrating different degrees of TRG development are described; all occur at high-level (>840 m) sites that remained glacier-free during the LLS, and all lack plausible alternative explanations. The apparent scarcity of relict TRGs even in the Cairngorms may reflect the development of ‘cold’ permafrost and/or a lengthy time lag between permafrost development and the accumulation of a sufficient volume and thickness of ground ice to permit permafrost creep and deformation of an overlying mantle of bouldery debris. In consequence, relict TRGs may occur only at favourable high-level sites where permafrost developed earliest.

Using seismic petrophysical modeling and prestack simultaneous inversion to provide insights into the physical properties of uranium-bearing reservoirs: Implications for favorable sites of sandstone-hosted uranium deposits

Seismic prospecting has been accepted as one of the most widely available methods for exploring sandstone-hosted uranium deposits (SUDs). However, conventional seismic interpretation faces a challenge in the identification and characterization of a uranium reservoir’s complexity. How to characterize in detail a uranium reservoir’s physical complexity and effectively improve uranium reservoir prediction accuracy remain unresolved problems. To address this, we develop a novel combination of petrophysical modeling and prestack simultaneous inversion to understand in detail the physical properties of uranium-bearing reservoirs and efficiently predict favorable SUD sites. First, we develop a workflow of rock-physics modeling for SUD logs using the Xu-White method to calculate the modulus of elasticity of the grain matrix; subsequently, we extend the Walton model for the modulus prediction of the dry rocks and the Gassmann equation for one of the saturated rocks after a massive calculation test; and then, we predict the S-wave data used for the following inversion. Second, we execute a prestack simultaneous inversion to obtain the petrophysical parameters (e.g., P-impedance, density [[Formula: see text]], shear modulus [[Formula: see text]], Lamé coefficient [[Formula: see text]], and Young’s modulus) that can provide insights into the physical properties of a uranium metallogenic environment. Accordingly, we discover that sites bearing uranium mineralization strongly correspond to areas with low elastic-parameter values (especially [Formula: see text] and [Formula: see text]), whereas nonuranium anomalies occur in high-value sites. This indicates that weakened elastic characteristics are caused by the enhancement of the total organic content and total clay mineral volumes of the uranium-bearing layers. In summary, the developed combination approach can yield an effective and accurate characterization of the geologic properties of uranium-bearing formations, and it can provide prediction factors (e.g., parameters related to the shear modulus) for uranium mineralization.

Graphene-like BGe monolayer as anode material for metal-ions batteries: Computational predictions

Magnesium-, calcium- and potassium-ion batteries (MIBs, CIBs and PIBs) have attracted extraordinary attention as alternative batteries of lithium-ion batteries, due to their due to their abundancies, the low cost, safety. Herein, we investigated the suitability of BGe monolayer as anode material for MIBs, CIBs, and PIBs by using first-principles calculations in framework of density functional theory (DFT). The energy adsorption calculations and the charge transfer analysis show that the hollow site is the most favorable site for Mg, Ca, and K atoms adsorption on the BGe monolayer. In addition, the BGe monolayer has remained the same, preserving its metallic behavior after Mg, Ca and K atoms adsorption, which is suitable for batteries applications. The open circuit voltage ranges from 1.03 V to 1.02, 1.86 V to 1.67 V, and 2.85 V to 2.28 V for Mg, Ca, and K, respectively. Especially, the BGe monolayer exhibits a high theoretical specific capacity, up to 1284.63 mAhg−1 for Mg and Ca, and 642.31 mAhg−1 for K, which are higher than other monolayers. In addition, the BGe monolayer can provide a good charging-discharging processes with a low diffusion barrier of 0.80, 0.52, and 0.17 eV for Mg, Ca, and K-ion, respectively. All these properties indicate that the BGe monolayer is promising anode material for Mg/Ca/K ion batteries.