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The data included in this Dryad submission was collected in order to understand how the model organism* Escherichia coli* overcomes stabilized G-quadruplexes. This work involved a multi-omics approach to studying how the G-quadruplex stabilizers NMM and Braco-19 impact growth, gene importance, and mRNA/proteomic abundance in G-quadruplex stabilizing conditions.
We present a novel spatial discretization for the anisotropic heat conduction equation, aimed at improved accuracy at the high levels of anisotropy seen in a magnetized plasma, for example, for magnetic confinement fusion. The new discretization is based on a mixed formulation, introducing a form of the directional derivative along the magnetic field as an auxiliary variable and discretizing both the temperature and auxiliary fields in a continuous Galerkin (CG) space. Both the temperature and auxiliary variable equations are stabilized using the streamline upwind Petrov–Galerkin (SUPG) method, ensuring a better representation of the directional derivatives and therefore an overall more accurate solution. This approach can be seen as the CG-based version of our previous work (Wimmer, Southworth, Gregory, Tang, 2024), where we considered a mixed discontinuous Galerkin (DG) spatial discretization including DG-upwind stabilization. We prove consistency of the novel discretization, and demonstrate its improved accuracy over existing CG-based methods in test cases relevant to magnetic confinement fusion. This includes a long-run tokamak equilibrium sustainment scenario, demonstrating a 35% and 32% spurious heat loss for existing primal and mixed CG-based formulations versus 4% for our novel SUPG-stabilized discretization.
Systems and methods for voltage stability monitoring and active/reactive power support are disclosed herein. In some embodiments, a smart electric meter of an end user in a grid power system can measure the voltage supplied to the end user via the grid power system, and can analyze the voltage data to detect critical voltage characteristics. The critical voltage characteristics may indicate that a voltage collapse event is likely. The smart electric meter can further estimate a voltage stability margin based on the voltage data. If necessary, the smart electric meter can control an electrical power source and/or an electric appliance positioned at or near the end user to increase the voltage stability margin.
FLORA solves, in a 2-D domain (radial and axial dimensions) with a specified azimuthal Fourier mode, for the linearized stability of a long, thin, axisymmetric plasma equilibrium in an applied magnetic field. Before the stability equation is solved, FLORA solves a set of simple equations for pressure balance that specify the equilibrium magnetic field and plasma pressure in the long-thin limit given a simplified description of the magnetic coils. It uses an initial-value method for the linear stability problem in which an equilibrium is given an initial perturbation to its magnetic field, and the temporal behavior of the perturbation is followed. The perturbation has been Fourier expanded in the azimuthal coordinate; each azimuthal mode must be examined separately. The complex partial differential equation of motion for the perturbed radial displacement of the field lines is solved as a coupled system of two real p.d.e.'s and the solution consists of two parts, the real part and the imaginary part. The system is solved by bringing the coupling terms in each equation to the right side and using an iterative technique.
The multiport autonomous reconfigurable solar (MARS) power plant is a promising solution to integrate renewable resources and energy storage systems into the alternating current (ac) power grid and an high-voltage direct current (HVdc) link. In the MARS system, various input power sources are connected to the individual submodules (SMs) through direct current (dc)–dc converters. However, the presence of external power sources can result in unbalanced capacitor voltages of SMs, thereby violating stability constraints under multiple/diverse operating conditions. This article aims to address the gap by accurately determining the stability boundary of the MARS system. As such, a novel machine learning (ML)-assisted energy balancing control (EBC) criterion is proposed. Further, in conjunction with a refined EBC, this approach ensures balanced capacitor voltages across various types of SMs, significantly enhancing the overall system efficiency. The proposed EBC criterion effectively controls EBC activation and deactivation, achieving remarkable accuracy. Both power systems computer aided design (PSCAD)/electromagnetic transients including direct current (EMTDC) simulations and control hardware-in-the-loop (cHIL) tests are conducted to validate the feasibility and efficiency of the proposed method. By combining the EBC and ML-assisted EBC criterion, efficient energy management is achieved for systems featuring multiple input power sources, such as MARS. This approach enables the system to fully exploit its potential across an expanded operational range while upholding high-efficiency standards.
Iodine electrochemistry plays an important role in driving iodide‐oxidation induced halide migration in 3D halide perovskites. When subjected to light illumination or electrochemical bias, mixed halide perovskites undergo halide segregation followed by iodine expulsion from the crystal lattices. To mitigate such intrinsic halide ion mobility in 3D perovskites, lower‐dimensional (2D) perovskites are employed as barriers to stabilize the perovskite layers. Interestingly, 2D halide perovskites also exhibit halide ion mobility that is dependent on the binding configuration, viz., Ruddlesden–Popper (RP) and Dion–Jacobson (DJ) phases. Hybrid RP‐DJ perovskites with a mixed Br:I ratio of 50:50 show increased stability following continuous photoirradiation. Spectroscopic studies that probe iodine migration and expulsion in photoirradiated 2D films of different configurations are presented here. The effective strategy of blending two different 2D phases (RP‐DJ) offers new opportunities to develop stable 2D/3D perovskite interfaces in solar cells.
Li-rich Mn-based layered oxides (LLO) hold great promise as cathode materials for lithium-ion batteries (LIBs) due to their unique oxygen redox (OR) chemistry, which enables additional capacity. However, the LLOs face challenges related to the instability of their OR process due to the weak transition metal (TM)-oxygen bond, leading to oxygen loss and irreversible phase transition that results in severe capacity and voltage decay. Herein, a synergistic electronic regulation strategy of surface and interior structures to enhance oxygen stability is proposed. In the interior of the materials, the local electrons around TM and O atoms may be delocalized by surrounding Mo atoms, facilitating the formation of stronger TM—O bonds at high voltages. Besides, on the surface, the highly reactive O atoms with lone pairs of electrons are passivated by additional TM atoms, which provides a more stable TM—O framework. Hence, this strategy stabilizes the oxygen and hinders TM migration, which enhances the reversibility in structural evolution, leading to increased capacity and voltage retention. This work presents an efficient approach to enhance the performance of LLOs through surface-to-interior electronic structure modulation, while also contributing to a deeper understanding of their redox reaction.
Mixed Sn–Pb perovskites provide the 1.2–1.3 eV narrow-bandgap absorber needed for high efficiency of all perovskite tandems, but their deployment is limited by operational instability under light. This review synthesizes mechanistic origins and recent mitigation strategies for mixed Sn–Pb perovskite solar cells. The oxidation of Sn 2+ to Sn 4+ , often driven by iodine formation under light and bias, is the primary failure pathway; it creates Sn vacancies, self-doping, and nonradiative loss. Surface/grain-boundary defects, halide migration, reactive oxygen species, and interfacial redox at charge-transport layers, along with hole accumulation from poor band alignment, further accelerate Sn–Pb perovskite degradation. Here we survey recent stability advances across additive chemistry, surface and grain-boundary passivation, buried-interface redesign with modified or alternative hole transport layers, and solvent systems that preserve Sn 2+ and correct Sn–Pb speciation for scalable coating. Together, these recent advances have enabled devices to retain 80%–90% output for hundreds to over a thousand hours. Lastly, we provide our perspectives on further improving the operational stability of Sn–Pb perovskite and solar cells.
Amphiphilic charged oligomers (oligodimethylsiloxane – methylimidazolium cation, ODMS-MIM (+) ), assemble into bilayers using the droplet interface bilayer (DIB) platform, possess similar size and functionality as phospholipid bilayers, but exhibit increased stability. The oligomer ionic headgroups (MIM (+) ) are covalently bound to monodisperse, short-chain (n = 13) hydrophobic tails (ODMS). These self-assemble as monolayer brushes at the oil–aqueous interface of water droplets that are influenced by both the charged cationic headgroups, and the nature of the covalently attached tails in the organic phase. Charge regulation (CR) stabilizes the formation of ordered, molecularly close-packed brush phases, which results in highly insulating, stable DIB membranes, with contributions from specific ion-pairing effects, Debye screening, and voltage-dependent electrocompressive stresses. In the oil phase, interactions between hexadecane, a good solvent for ODMS, and the hydrophobic tails result in extended waiting times for bilayer formation compared to phospholipid DIBs, for which hexadecane is a poor solvent. Close agreement between experimental values and predictions for two key parameters, the critical membrane thickness, h c , and maximal grafted headgroup density, Γ 0 , validate an electrostatic CR model consisting of adsorption and partial neutralization of counterions at a charged interface.
Colloidal perovskite nanoplatelets (NPLs), despite their exceptional optoelectronic properties, face significant challenges due to their intrinsic instability and trap-assisted non-radiative recombination. Although many studies employing surface engineering, such as selecting ligands or coating to passivate defects, have demonstrated improved optoelectronic properties, these enhancements are typically inferred from bulk-ensemble measurements; the effects at the single-particle level remain elusive. Here, we conduct single-particle-level studies using scanning tunneling spectroscopy (STS) on a unique core–crown system, CsPbBr 3 @FAPbBr 3 NPLs, where the lateral surfaces of the CsPbBr 3 core are coated with an FAPbBr 3 crown. Experimental density-of-states (DOS) analysis reveals a 47% reduction in deep-trap states in core-crown NPLs compared to core-only NPLs, consistent with nearly two-fold enhancements in photoluminescence quantum yields. Progressive I–V sweep measurements demonstrate superior electrical stability in core-crown NPLs, preserving band structure with minimal degradation, while core-only NPLs exhibit rapid bandgap shrinkage and trap formation. Density functional theory (DFT) calculations indicate that FA incorporation distorts Pb octahedral lattice, widening the bandgap. This study elucidates how surface engineering modulates charge localization, passivates defects, and enhances stability at the single-particle level. Moreover, by uncovering bias-induced trap states in single unpassivated NPLs, this study establishes a precise, robust approach for characterizing emerging perovskite nanocrystals.
Co-free Li-rich layered oxides (CFLLOs) with anionic redox activity are among the most promising cathode materials for high-energy-density and low-cost lithium-ion batteries (LIBs). However, irreversible oxygen release often causes severe structural deterioration, electrolyte decomposition, and the formation of unstable cathode-electrolyte interface (CEI) film with high impedance. Additionally, the elimination of cobalt elements further deteriorates the reaction kinetics, leading to reduced capacity and poor rate performance. Here, in this study, a multifunctional strategy is proposed, incorporating Li 2 MnO 3 phase content regulation, micro-nano structure design, and heteroatom substitution. The increased content of Li 2 MnO 3 phase enhances the capacity through oxygen redox. The smaller nanoscale primary particles induce greater tensile strain and introduce more grain boundaries, thereby improving the reaction kinetics and reactivity, while the larger micron-sized secondary particles help to reduce interfacial side reactions. Furthermore, Na⁺ doping modulates the local coordination environment of oxygen, stabilizing both the anion framework and the crystal structure. As a result, the designed cathode exhibits enhanced rate performance, delivering a capacity of 158 mAh g⁻¹ at 5.0 C and improved cyclic stability, with a high capacity retention of 99% after 400 cycles at 1.0 C. This multifunctional strategy holds great promise for advancing the practical application of CFLLOs in next-generation LIBs.
As part of an ongoing series aimed at optimizing Fe-9Cr reduced activation ferritic/martensitic (RAFM) alloys for fusion energy systems, this study explores MX precipitate behavior under dual-ion irradiations, specifically examining correlations between helium transmutation and irradiation-induced damage. Utilizing single and dual-beam ion irradiation, the research explores the combined effects of helium (10–25 appm He/dpa), temperature (400–600 °C), and damage levels (15–100 dpa) on the microstructural evolution of CNA9 steel, a variant of Castable Nanostructured Alloys (CNAs). The study demonstrates that helium co-implantation hinders radiation-enhanced coarsening of MX-TiC precipitates at 500 and 600 °C, maintaining MX-TiC precipitate stability at moderate damage levels (15 dpa) but failing to prevent complete precipitate dissolution at higher damage levels (≥50 dpa) when irradiated at 500 °C. Here, a generalized precipitate stability model suggests that helium-induced suppression of diffusion alters the balance between recoil resolution and back diffusion for MX-TiC precipitates, enhancing the current understanding of precipitate behavior under damage and transmutation simulated dual-ion irradiation conditions.
In an effort to optimize Fe-9Cr reduced activation ferritic/martensitic (RAFM) steels and to inform the design and operation of fusion reactors, this work represents the first in a series of cohesive studies dedicated to the evolution of MX-TiC precipitates under accelerated single and dual ion irradiations. This study investigates CNA9, a simplified Fe-9Cr RAFM steel featuring initial MX-TiC precipitate densities of (2.3±0.3)×10²¹ m⁻³. This material was subjected to single self-ion irradiation at damage levels ranging from 1 to 100 displacements per atom (dpa) over a temperature range of 300 to 600°C, with a nominal dose rate of 7×10⁻⁴ dpa/s. Irradiation-induced coarsening was observed, as evidenced by statistically significant increases in mean diameter sizes, at 15 dpa at both 500°C and 600°C, whereas no coarsening was noted at 300°C or 400°C. Further, complete dissolution of precipitates occurred at damage levels of 50 and 100 dpa across the two temperatures tested (300°C and 500°C) while no significant changes were observed at any doses below 15 dpa at 500°C. Experimentally parameterized recoil resolution modeling suggests that the observed radiation stability of MX-TiC precipitates is intricately linked to diffusional changes of solutes resulting from the co-evolution of microstructural features within the experiments. The findings align with current theoretical perspectives on radiation-induced precipitate stability in complex alloys.
The impurity or alloying atoms in YH 2 can alter the local electronic structure and so the hydrogen defect stability, as well as the H migration barrier energy. Thus, DFT calculations were employed to determine the effect of foreign elements from alkali and alkaline earth metals to transition metals and one critical impurity element, O, on H vacancy stability and retention characteristics in YH2. Results revealed that alloying elements act as hydrogen vacancy sinks by reducing the vacancy formation energy at neighboring sites. The implantation of non-magnetic foreign elements (s1, s2, and d10 valence electrons) in hydrogen energy landscape was calculated to be minor; while the hydrogen vacancy formation energy was reduced from 1.37 eV to 1.00 eV, the migration energy barrier of hydrogen was increased from 0.87 eV to 1.15 eV for non-magnetic foreign elements. The migration energy barrier monotonically decreased with increasing d-shell occupancy, reaching as low as 0.4 eV for Cr, Mo(d4), and Fe (d4). Alloying with late transition metals (d8 and d9) moderately impacted the hydrogen vacancy formation. Finally, it was found to be O addition into the YH 2- lattice did not alter the energy landscape of hydrogen vacancies. Since alloyed YH 2 has not been studied extensively, this study provides an atomistic understanding how alloying elements and impurities trap vacancies and affects hydrogen mobility YH 2 . Meanwhile, the main findings of this study may serve as guidelines for introducing alloying elements in ZrH 2 as well.
Stabilizing weak clayey soils with lime is an effective method for improving the mechanical properties of soil. However, lime production is an energy-intensive process producing significant CO 2 emissions in lime-stabilized soils, which can be counteracted through accelerated carbonation that enhances its engineering performance. The present study evaluates accelerated carbonation of lime-treated soils by adding gaseous (CO 2 -rich gas), liquid (water-CO 2 mixture), and solid (sodium bicarbonate) CO 2 sources. Results indicated that samples carbonated with gaseous CO 2 exhibited 100% lime carbonation, while samples treated with solid and aqueous sources of CO 2 had a mean lime carbonation of 60% and 40%, respectively. Further, all lime-treated-carbonated samples exhibited a mean 50% increase in unconfined compressive strength compared to the untreated samples after a 7-day curing period. Durability evaluation through cyclic wetting and drying indicated that the carbonated samples had higher durability than the untreated samples. X-ray computed tomography showed that adding solid and liquid sources of CO 2 facilitated the flocculation of montmorillonite, reducing the porosity. However, a higher dosage of solid CO 2 induced clay dispersion, increasing the porosity. X-ray diffraction and thermogravimetric analysis verified CO 2 sequestration through the formation of calcite, a thermodynamically stable polymorph of calcium carbonate.
In a computational fluid model of the atmosphere, the advective transport of trace species, or tracers, can be computationally expensive. For efficiency, models often use semi-Lagrangian advection methods. High-order interpolation semi-Lagrangian (ISL) methods, in particular, can be extremely efficient, if the problem of property preservation specific to them can be addressed. Atmosphere models often use geometrically and logically nonuniform grids for efficiency and, as a result, element-based discretizations. Such grids and discretizations make stability a particular problem for ISL methods. Generally, high-order, element-based ISL methods that use the natural polynomial interpolant associated with a nodal finite-element discretization are unstable. Here, we derive new bases having order of accuracy up to nine, with positive nodal weights, that stabilize the element-based ISL method. We use these bases to construct the linear advection operator in the property-preserving Interpolation Semi-Lagrangian Element-based Transport (Islet) method. Then we discuss key software implementation details. Finally, we show performance results for the Energy Exascale Earth System Model's atmosphere dynamical core, comparing the original and new transport methods. These simulations used up to 27,600 Graphical Processing Units (GPU) on the Oak Ridge Leadership Computing Facility's Summit supercomputer.
Numerical simulations are essential to evaluate the performance and safety of engineered subsurface systems such as geological carbon storage sites, enhanced geothermal fields, and oil and gas reservoirs. A key challenge lies in accurately modeling the frictional contact behavior along fault surfaces. This problem involves inequality constraints that arise from the physics of frictional slip, requiring specialized numerical methods to handle the resulting highly nonlinear and path-dependent behavior. Here, in this work, we address this challenge using an Augmented Lagrangian Method (ALM) implemented via the Uzawa algorithm. The formulation employs mixed finite element spaces, combining low-order piecewise linear displacements within the 3D domain cells with piecewise constant tractions defined on the fault surfaces. Furthermore, to ensure stability and satisfy the inf-sup condition, the discrete displacement space is enriched with face bubble functions on both sides of the contact interfaces. This approach offers several advantages over other stabilization techniques that rely on additional terms, and it integrates naturally in the Uzawa framework.
Incorporating organic bulky cations in the precursor or post-treatment to achieve two-dimensional/three-dimensional (2D/3D) heterojunction is an effective strategy for enhancing the stability of perovskite materials. However, the issue of insufficient charge transport in 2D perovskites limits their development, and the fundamental mechanism of out-of-plane carrier transport remains unclear. This study designed and synthesized seven organic phenyl-core cations, differentiated at the 1- and 1,4-positions, and identified the impacts on the corresponding properties of the 2D crystalline perovskite. Shorter cations facilitated a more compact arrangement of adjacent inorganic layers, aligning to favor charge transport along the vertical direction. In addition, introducing high electronegativity led to increased intermolecular interactions, resulting in enhanced structural stability and improved phenyl ring π-orbital overlap and interlayer electron coupling, yielding efficient charge transport. Resilience to thermal stressing of the perovskite was strongly correlated with the carbon chain length of the spacer cations. Here, the increase in cation length and the reduction in the rigidity of the amino-terminal both aided in the dispersion of thermal stress in the inorganic framework. Additional hydrogen bonding also contributed to mitigating structural disorder.