Asymmetric Evolution Research Articles

Multifunctional benzoselenadiazole-capped organic molecule-based nanohybrid for efficient asymmetric supercapacitor and oxygen evolution reaction

Multifunctional benzoselenadiazole-capped organic molecule-based nanohybrid for efficient asymmetric supercapacitor and oxygen evolution reaction

The effect of fire-wall distance on the flame attachment characteristics and flame height of near-wall fires

Near-wall fires happen frequently in buildings and may ignite the solids on the wall, leading to a rapid spread of fire. A series of experiments and numerical simulations were conducted on near-wall and free (the same as that of near-wall fire source after mirroring) fires using propane and methane as the fuel to investigate the effect of the wall on flame attachment properties and flame height. The presence of a wall decreases the degree of turbulence for downstream flame and influences the velocity and temperature evolutions due to the no-slip and impermeability conditions. Due to the asymmetric evolution of vortices, intermittent flame attachment emerges at a certain downstream location and is intensified with decreasing fire-wall distance. The upper attachment limit increases with the heat release rate, however, the dependence of the lower attachment limit on the heat release rate is related to the fire-wall distance. The flame attachment probability increases with the aspect ratio of the gap between the fire source and the wall. Grashof number is a suitable parameter to correlate the flame attachment parameters of near-wall fires, including flame attachment limit, length and probability. The flame height increases with decreasing fire-wall distance and is 17.8%∼46.5% higher than that of free fires. By defining a dimensionless heat release rate incorporating the flame attachment probability, a unified model was built to predict the flame height of near-wall and free fires. The data and models are expected to be useful for evaluating the risk of early-stage near-wall fires.

Kinematic and rheological controls on ultra-wide asymmetric rifted margins evolution

Only a limited number of geodynamic numerical models have been successful in simulating both asymmetric and ultra-wide (>500 km) rifted margins. In this paper, we present a comprehensive suite of 72 thermo-mechanical geodynamic numerical simulations of rifting. These simulations revealed the impact of initial crustal thickness, variations in the ratios between the upper and lower crusts, rift velocity, structural inheritance, and shear heating on the asymmetry and width of conjugate rifted margins. Our findings highlight that initial crustal thickness is a primary controlling factor of conjugate rifted margin geometries. Specifically, initial crustal thicknesses ranging from 35 to 40 km generally do not result in margins exceeding 300 km in width, where wider margins are 1.5 times longer than the narrow corresponding conjugate. An initial crustal thickness of 45 km facilitates the formation of ultra-wide margins, especially when the upper crust is thicker than the lower crust. This is attributed to the greater concentration of heat-producing elements in the thicker upper crust, which accumulates heat, weakens the crust, and promotes ductile thinning. Additionally, high rifting velocities enhance advective heating from the upwelling asthenosphere. This further influences the development of the distal margin domains and results in highly asymmetric conjugate margin pairs with one ultra-wide margin. Structural inheritance also emerges as a critical factor, as it distributes strain within the pre-rift lithosphere, thereby enhancing the development of ultra-wide (>500 km) and highly asymmetric margins. Our results are compatible with conjugate rifted margins between Brazil and Africa, such as Espirito Santo - North Kwanza, Campos - South Kwanza and Santos - Benguela.

Beyond symmetry: Investigating asymmetric melt pool evolution in multi-pulse laser surface melting

A numerical investigation is carried out to explore the intricacies of multi-pulse pulsed laser surface melting (pLSM) to understand its impact on surface evolution. A finite-element-based multi-phase model with temperature-dependent properties is employed to track the interface for multiple laser pulses. Examining various overlap spacings and conducting a comparative analysis of the number of pulses, the study focuses on the exclusive influence of overlapping in surface texture generation. Notably, the assumption of an initially flat surface eliminates the effects of the initial surface roughness to provide unique insights completely based on multi-pulse dynamics. While the first pulse on a flat initial surface resulted in a symmetric surface evolution, asymmetric melt pools were observed in the second pulse and subsequent pulses. The asymmetry results from non-uniform cooling and melt pool flows influenced by the surface evolved in the first pulse. The topography-driven surface tension from the first pulse made the trailing peak solidify slower than the leading peak. The asymmetry was significant for smaller overlaps between the two pulses and reduced as the overlap increased. Further, an increase in the number of laser pulses promotes the generation of identical asymmetric surface features. In conclusion, the study demonstrates the importance of the developed model in accurately predicting the surface evolution influenced by topography-driven surface tension and that single pulse axisymmetric models are insufficient.

Induced Manipulation of Atomically Dispersed Cobalt through S Vacancy for Photocatalytic Water Splitting: Asymmetric Coordination and Dynamic Evolution.

It is still a challenge to construct single-atom level reduction and oxidation sites in single-component photocatalyst by manipulating coordination configuration for photocatalytic water splitting. Herein, the atomically dispersed asymmetric configuration of six-coordinated Co-S2O4 (two exposed S atoms, two OH groups, and two Co─O─Zn bonds) suspending on ZnIn2S4 nanosheets verified by combining experimental analysis with theoretical calculation, is applied into photocatalytic water splitting. The Co-S2O4 site immobilized by Vs acts as oxidation sites to guide electrons transferring to neighboring independent S atom, achieving efficient separation of reduction and oxidation sites. It is worth mentioning that stabilized Co-S2O4 configuration show dynamic structure evolution to highly active Co-S1O4 configuration (one exposed S atom, one OH group, and three Co─O─Zn bonds) in reaction, which lowers energy barrier of transition state for H2O activization. Ultimately, the optimized photocatalyst exhibits excellent photocatalytic activity for water splitting (H2: 80.13 µmol g-1 h-1, O2: 37.81 µmol g-1 h-1) and outstanding stability than that of multicomponent photocatalysts due to dynamic and reversible evolution between stable Co-S2O4 configuration and active Co-S1O4 configuration. This work demonstrates new cognitions on immobilized strategy through vacancy inducing, manipulating coordination configuration, and dynamic evolution mechanism of single-atom level catalytic site in photocatalytic water splitting.

Effect of βSn grain orientations on the electromigration-induced evolution of voids in SAC305 BGA solder joints

The electromigration (EM) failure of solder joints is closely related to the development of voids during EM. In this paper, an integrated approach combining experimentation and finite element simulation was employed to reveal the evolution of voids in solder joints under current stress. The results indicate that the quantity and volume of voids near the cathode consistently increase, while those close to the anode decrease. These asymmetric evolutions of voids are mainly due to the Sn flux, which is controlled by both current density and βSn grain orientation. The magnitude of Sn flux increases with higher current densities and larger angles γ between the c-axis of βSn and the current direction. The direction of Sn flux is more significantly influenced by the current direction rather than the βSn orientation, due to the weak anisotropic self-diffusion of Sn. Voids near the anode tend to shrink while those close to the cathode expand, parallel to the substrate, due to higher Sn flux distributions at the waists of voids, where current crowding is seen. Void splitting related to rapid Cu diffusion has been observed, leading to an abnormal increase in the number of voids near the cathode. This study enhances the understanding of the electromigration failure mechanisms involving void evolution in solder joints.

Low-mass planets falling into gaps with cyclonic vortices

ABSTRACT We investigate the planetary migration of low-mass planets ($M_p\in [1,15]\, \mathrm{ M}_{\oplus }$, here $\mathrm{ M}_{\oplus }$ is the Earth mass) in a gaseous disc containing a previously formed gap. We perform high-resolution 3D simulations with the fargo3d code. To create the gap in the surface density of the disc, we use a radial viscosity profile with a bump, which is maintained during the entire simulation time. We find that when the gap is sufficiently deep, the spiral waves excited by the planet trigger the Rossby wave instability, forming cyclonic (underdense) vortices at the edges of the gap. When the planet approaches the gap, it interacts with the vortices, which produce a complex flow structure around the planet. Remarkably, we find a widening of the horseshoe region of the planet produced by the vortex at the outer edge of the gap, which depending on the mass of the planet differs by at least a factor of two with respect to the standard horseshoe width. This inevitably leads to an increase in the co-rotation torque on the planet and produces an efficient trap to halt its inward migration. In some cases, the planet becomes locked in co-rotation with the outer vortex. Under this scenario, our results could explain why low-mass planets do not fall towards the central star within the lifetime of the protoplanetary disc. Lastly, the development of these vortices produces an asymmetric temporal evolution of the gap, which could explain the structures observed in some protoplanetary discs.

Synergistic performance of Ag-MOF@V2CTx composite for asymmetric supercapacitors and hydrogen evolution reaction

Extensive research is underway to process viable electrode materials for energy storage and hydrogen production. This study focuses on synthesizing Ag-MOF and V2CTx, followed by their combination in a 50/50 wt% ratio to produce Ag-MOF@V2CTx composite. Utilizing a three-electrode design, Ag-MOF@V2CTx exhibits specific capacitance 2180 Cg-1 at current density of 2.0 A/g. BET testing reveals a significant specific surface area of 147 m2/g, enhancing electrochemical performance. The supercapattery which is constructed with Ag-MOF@V2CTx and activated carbon, yields a charge specific capacity of 283 Cg-1. The Ag-MOF@V2CTx//AC configuration achieves a power density of 1230 Wkg-1 and energy density of 75.12 Whkg−1. Remarkably, behind 10,000 GCD cycles, Ag-MOF@V2CTx device retains 85 % of its capacity. Moreover, among all composites evaluated in (HER), Ag-MOF@V2CTx exhibits the lowest overpotential (119 mV). These findings underscore the significance of Ag-MOF@V2CTx as electrode materials for energy storage devices and various energy applications.

The genome of Lespedeza potaninii reveals biased subgenome evolution and drought adaptation.

Lespedeza potaninii, a xerophytic subshrub belonging to the legume family, is native to the Tengger Desert and is highly adapted to drought. It has important ecological value due to its drought adaptability, but the underlying molecular mechanisms remain largely unknown. Here, we report a 1.24 Gb chromosome-scale assembly of the L. potaninii genome (contig N50 = 15.75 Mb). Our results indicate that L. potaninii underwent an allopolyploid event with 2 subgenomes, A and B, presenting asymmetric evolution and B subgenome dominance. We estimate that the 2 diploid progenitors of L. potaninii diverged around 3.6 million years ago (MYA) and merged around 1.0 MYA. We revealed that the expansion of hub genes associated with drought responses, such as the binding partner 1 of accelerated cell death 11 (ACD11) (BPA1), facilitated environmental adaptations of L. potaninii to desert habitats. We found a novel function of the BPA1 family in abiotic stress tolerance in addition to the known role in regulating the plant immune response, which could improve drought tolerance by positively regulating reactive oxygen species homeostasis in plants. We revealed that bZIP transcription factors could bind to the BPA1 promoter and activate its transcription. Our work fills the genomic data gap in the Lespedeza genus and the tribe Desmodieae, which should provide theoretical support both in the study of drought tolerance and in the molecular breeding of legume crops.

Effect of fluid–structure interaction on the oblique water entry of the projectile under the influence of floating ice structure

The water entry of a projectile constrained by polar floating ice presents a unique cross-media challenge. This paper investigates the dynamics of oblique water entry for a projectile influenced by floating ice using the fluid–structure interaction (FSI) method. The validity of the numerical method has been confirmed through experimental validation. The water entry process of a projectile from the side of the floating ice is examined. The evolution of the cavity and the movement patterns of objects as the distance between the projectile and the floating ice decreases toward collision are investigated. The influence of water on the critical collision distance between the projectile and the floating ice during oblique water entry is analyzed. Additionally, the physical mechanism of floating ice deflection through collision is investigated based on the theory of cavity dynamics. Subsequently, the study focuses on the oblique water entry process of a projectile colliding with the upper surface of the floating ice. Different entry angles determine the collision mode between the projectile and the floating ice surface. This study also examines how varying entry angles influence cavity evolution and object movement patterns during oblique collisions. Different collision modes between the projectile and the floating ice lead to asymmetric cavity evolution and various modes of object deflection motion. Finally, changes in the flow field and vortex structure during oblique collisions are studied to examine the influence of the FSI process between the projectile and the floating ice on the flow field.

A new 3D asymmetric double-Gaussian wake analytical model for horizontal-axis wind turbines

A new three-dimensional analytical model named 3DADG that is able to describe asymmetric evolution of wind turbine wake is proposed in this paper. Due to the combined effects of wind wheel rotation and wind shear effects wake attenuation shows asymmetric properties. However, existing wake analytical models fail to describe such unique properties. To solve this problem, spatial dependencies of the wake expansion rate and deficit coefficient are revealed to successfully present horizontal attenuations of the wake varying from asymmetric-double-Gaussian in the near and transition wake regions, and then to single-Gaussian in the far wake region. The wind shear effect is also considered in the model to include asymmetric vertical wake speed attenuation. This model is derived from the laws of mass and momentum conservation. It is verified through comparisons with the results of wind tunnel “blind test” and LES simulation. The model proposed is capable to show spatial evolution of wind turbine wake from a three-dimensional perspective. Sensitivities of thrust coefficient and turbulence intensity to the model are also investigated. It not only promotes development of wake analytical model but also provides a useful tool for power prediction and wake control of wind farms under wake effects.

Asymmetric evolution of ISG15 homologs and the immune adaptation to LBUSV infection in spotted seabass (Lateolabrax maculatus)

The battle between host and viral is ubiquitous across all ecosystems. Despite this, research is scarce on the antiviral characteristics of fish, particularly in those that primarily rely on innate immune responses. This study, comprehensively explored the genetic and antiviral features of ISG15 in spotted seabass, focusing on its response to largemouth bass ulcerative syndrome virus (LBUSV). Through whole-genome BLAST and PCR cloning, two ISG15 homologs, namely LmISG15a and LmISG15b, were identified in spotted seabass, both encoding highly conserved proteins. However, a distinctive contrast emerged in their expression patterns, with LmISG15a exhibiting high expression in immune organs while LmISG15b remained largely silent across various organs. Regulatory elements analysis indicated an asymmetric evolution of the two ISG15s, with the minimal expression of LmISG15b may attribute to the loss of a necessary ISRE and an additional instability "ATTTA" motif. Association analysis demonstrated a significant correlation between LmISG15a expression and LBUSV infection. Subsequent antiviral activity detection revealed that LmISG15a interacted with LBUSV, inhibiting its replication by activating ISGylation and downstream pro-inflammatory mediators. In summary, this study unveils a distinct evolutionary strategy of fish antiviral gene ISG15 and delineates its kinetic characteristics in response to LBUSV infection.

Post-impact lamella evolution of drop impact on superhydrophobic cylindrical surfaces at high Weber number

Drop surface interaction is omnipresent in nature and vital to many engineering applications. Most previous studies on drop impact dynamics on superhydrophobic cylindrical surfaces have focused on low-impact Weber (We) numbers, wherein the asymmetric bouncing behavior is the prominent outcome. However, it is observed that an impacting drop at higher impact We numbers (>100) exhibits more complex dynamics. The asymmetric post-impact lamella evolution in axial, and azimuthal directions are analyzed in detail. At higher impact velocities, the lamella expands in an azimuthal direction over the solid cylindrical surface, sweeping a certain angle followed by further expansion in air and over the solid surface until attaining the critical detachment angle or swiping angle, which is found to be a function of surface curvature and impact velocity. Thereafter, the expansion proceeds only in the air until the lamella completely shatters away, indicating the absence of a retraction phase in the azimuthal direction contrary to that during low-velocity impact. Lamella nucleation and film rupturing together, along with the ejection of satellite droplets, further add complexity. The present experimental study comprehensively evaluates the effect of higher Weber numbers (We up to 660) and surface curvature. Universal scaling relations are proposed for the lamella evolution in the axial and azimuthal directions based on the impact parameters to rationalize the same. A minimization of the surface energy approach has been hypothesized to predict the detachment angle utilizing the proposed scaling relations and is found to predict well with the experimental data.

Synergistic CuCoS-PANI materials for binder-free electrodes in asymmetric supercapacitors and oxygen evolution.

In advanced electronics, supercapacitors (SCs) have received a lot of attention. Nevertheless, it has been shown that different electrode designs that are based on metal sulfides are prone to oxidation, instability, and poor conductance, which severely limits their practical application. We present a very stable, free-standing copper-cobalt sulfide doped with polyaniline as an electrode coated on nickel foam (CuCoS/PANI). The lightweight nickel foam encourages current collection as well as serving as a flexible support. The CuCoS-PANI electrode had a substantially greater 1659 C g-1 capacity at 1.0 A g-1. The asymmetric supercapacitor (ASC) can provide an impressive 54 W h kg-1 energy density while maintaining 1150 W kg-1 power. Additionally, when employed as an electrocatalyst in the oxygen evolution reaction, CuCoS/PANI exhibited a 200 mV overpotential and 55 mV dec-1 Tafel slope, demonstrating its effectiveness in facilitating the reaction.

A Visual, In-Expensive, and Wireless Capillary Rheometer for Characterizing Wholly-Cellular Bioinks.

Rheological measurements with in situ visualization can elucidate the microstructural origin of complex flow behaviors of an ink. However, existing commercial rheometers suffer from high costs, the need for dedicated facilities for microfabrication, a lack of design flexibility, and cabling that complicates operation in sterile or enclosed environments. To address these limitations, a low-cost ($300) visual, in-expensive and wireless rheometer (VIEWR) using 3D-printed and off-the-shelf components is presented. VIEWR measurements are validated by steady-state and transient flow responses for different complex fluids, and microstructural flow profiles and evolution of yield-planes are revealed via particle image velocimetry. Using the VIEWR, a wholly-cellular bioink system comprised of compacted cell aggregates is characterized, and complex yield-stress and viscoelastic responses are captured via concomitantly visualizing the spatiotemporal evolution of aggregate morphology. A symmetric hyperbolic extensional-flow geometry is further constructed inside a capillary tube using digital light processing. Such geometries allow for measuring the extensional viscosity at varying deformation rates and further visualizing the alignment and stretching of aggregates under external flow. Synchronized but asymmetric evolution of aggregate orientation and strain through the neck is visualized. Using varying geometries, the jamming and viscoelastic deformation of aggregates are shown to contribute to the extensional viscosity of the wholly-cellular bioinks.

The asymmetric evolution of grain-scale stresses in notched specimens under cyclic loads

Engineering components are often exposed to various cyclic loading conditions. The development of microscale stresses under such conditions depends on the material texture, local microstructure, the degree of crystals elastic and plastic anisotropy, as well as the presence of geometrical irregularities. In this study, the three-dimensional synchrotron X-ray diffraction (3D-XRD) technique is used and coupled with a crystal plasticity finite element (CPFE) model to deconvolute the contribution of such parameters on the magnitude of localized stresses. Special attention is paid to the notch geometry, where two double-edge-notched α-zirconium specimens with different geometries but the same texture were deformed in-situ while grain-scale stresses were measured both in the vicinity of the notches and in the far-field zones. Deep and shallow notches were cut to the dimensions comparable with the specimens’ average grain sizes. For each specimen, the center of mass, orientation, elastic strain, stress, and relative volume of more than 6,000 grains were measured and studied. Post-deformation analysis with Electron Backscatter Diffraction (EBSD) was conducted to further validate the observed trends. It is shown that the distribution of grain-scale stresses is asymmetric within each specimen. This asymmetry develops from the early stages of the applied cyclic load and remains intact with further loading. A new method is introduced for quantifying the effects of grain neighbourhood on load sharing, where it is shown that such effects relax the stresses acting on “hard” grains, altering grain-scale stress concentration factors.

Two haplotype-resolved genome assemblies for AAB allotriploid bananas provide insights into banana subgenome asymmetric evolution and Fusarium wilt control

Bananas (Musa spp.) are one of the world’s most important fruit crops and play a vital role in food security for many developing countries. Most banana cultivars are triploids derived from inter- and intraspecific hybridizations between the wild diploid ancestor species Musa acuminate (AA) and M. balbisiana (BB). We report two haplotype-resolved genome assemblies of the representative AAB-cultivated types, Plantain and Silk, and precisely characterize ancestral contributions by examining ancestry mosaics across the genome. Widespread asymmetric evolution is observed in their subgenomes, which can be linked to frequent homologous exchange events. We reveal the genetic makeup of triploid banana cultivars and verify that subgenome B is a rich source of disease resistance genes. Only 58.5% and 59.4% of Plantain and Silk genes, respectively, are present in all three haplotypes, with >50% of genes being differentially expressed alleles in different subgenomes. We observed that the number of upregulated genes in Plantain is significantly higher than that in Silk at one-week post-inoculation with Fusarium wilt tropical race 4 (Foc TR4), which confirms that Plantain can initiate defense responses faster than Silk. Additionally, we compared genomic and transcriptomic differences among the genes related to carotenoid synthesis and starch metabolism between Plantain and Silk. Our study provides resources for better understanding the genomic architecture of cultivated bananas and has important implications for Musa genetics and breeding.

New Insights into Multiyear La Niña Dynamics from the Perspective of a Near-Annual Ocean Process

Abstract El Niño–Southern Oscillation (ENSO) exhibits highly asymmetric temporal evolutions between its warm and cold phases. While El Niño events usually terminate rapidly after their mature phase and show an already established transition into the cold phase by the following summer, many La Niña events tend to persist throughout the second year and even reintensify in the ensuing winter. While many mechanisms were proposed, no consensus has been reached yet and the essential physical processes responsible for the multiyear behavior of La Niña remain to be illustrated. Here, we show that a unique ocean physical process operates during multiyear La Niña events. It is characterized by rapid double reversals of zonal ocean current anomalies in the equatorial Pacific and exhibits a fairly regular near-annual periodicity. Mixed-layer heat budget analyses reveal comparable contributions of the thermocline and zonal advective feedbacks to the SST anomaly growth in the first year of multiyear La Niña events; however, the zonal advective feedback plays a dominant role in the reintensification of La Niña events. Furthermore, the unique ocean process is identified to be closely associated with the preconditioning heat content state in the central to eastern equatorial Pacific before the first year of La Niña, which has been shown in previous studies to play an active role in setting the stage for the future reintensification of La Niña. Despite systematic underestimation, the above oceanic process can be broadly reproduced by state-of-the-art climate models, providing a potential additional source of predictability for the multiyear La Niña events.

The J2 evolution model and control technology of the main roadway surrounding rock under superimposed influence of double-coal seam mining

Under double-seam mining, the main roadway surrounding rock is affected by the superposition of the advanced stress of the two-seam coal working faces. The stress superposition mode and degree are of great significance to the width calculation of the protective coal pillar and the determination of the critical control direction of the surrounding rock. This paper uses theoretical analysis, numerical simulation, and site engineering practice to carry out targeted research. The conclusions are as follows: Under different lateral pressure coefficients, the superposition evolution law of maximum principal stress direction of two coal seams with different offsets; Two developmental trends and three types of evolution models of J2 peak zone (the critical area of the stress increase and deflection changes) under different superimposed loading modes are summarized. Based on the typical asymmetric evolution model of the J2 peak zone, an asymmetric truss-cable co-anchoring method is proposed aimed at the J2 critical zone. The field monitoring results show that the main roadway surrounding rock is stable after support when the upper coal seam protective coal pillar is left 80 m, and the lower one is 60 m wide. It is of great reference importance for similar engineering practices.

Self-assembly of two dimensional (2-D) Zn0.5Cu0.5Co2O4 quasi-nanosheets for asymmetric supercapacitor and oxygen evolution reaction applications

Engineering the nanostructured ternary metal oxides with a high surface area is critical for multifunctional electrochemical applications. Herein, 2-D Zn0.5Cu0.5Co2O4 Quasi-nanosheets are prepared using the facile hydrothermal synthesis method and utilized for asymmetric supercapacitors and oxygen evolution reaction (OER) applications. As a supercapacitor electrode, the (2-D) Zn0.5Cu0.5Co2O4 quasi-nanosheets deliver a specific capacity of 669C g−1 at 1 A g−1 with a good rate capability of 339C g−1 at 30 A g−1 and withstand 96% of initial capacitance after 5000 cycles at 30 A g−1. In addition, the asymmetric supercapacitor Zn0.5Cu0.5Co2O4//AC (activated carbon) exhibits a high energy density of 55.1 W h kg−1 at a power density of 1280 W kg−1 and excellent cyclic stability of 94.9% capacity retention after 10000 charge/discharge cycles at 30 A g−1. In the OER process, the Zn0.5Cu0.5Co2O4 shows a low overpotential (160 mV at 20 mA cm−2), low Tafel slope (114.7 mV/dec), and high electrochemically active surface area. Moreover, the stability feature sustains for long-term use of 24 h. The post-physicochemical characterization techniques reveal the stability and mechanism of the supercapacitor electrode. The proposed approaches are significant for preparing various nanostructured ternary metal oxides for supercapacitors and water-splitting applications.