Evolution Of Configuration Research Articles

Strain-induced grain boundary migration and grain rotation in polycrystalline metals: Atomic-and meso-scale phase field simulations

The study reveals that in phase field (PF) simulations with over 300 grains, grain boundary (GB) migration exhibits anisotropic behavior and higher velocities under applied external loading. However, these simulations fail to provide detailed atomic-scale information about the evolution of grain orientation. Therefore, the researchers utilize phase field crystal (PFC) simulations to track the evolution of dislocation configurations and the annihilation of GB dislocations. The PFC simulations confirm a newly proposed plasticity process in nanocrystalline metals, where grain rotation is primarily dominated by dislocation climb and dislocation absorption at triple-junction points on GB, rather than GB sliding or diffusional creep as previously suggested. Furthermore, the PFC simulations demonstrate that the analysis of misorientation angles and GB dislocation evolution between neighboring grains can be quantitatively described using the Frank-Bilby equation. Thus, a hybrid approach of PF and PFC successfully describes in-situ transmission electron microscopy observations of GB migration and grain rotation for the first time. This multi-scale simulation method provides a deeper understanding of plasticity formation and development in nanostructured materials.

Pressure plateau of separation induced by shock impingement in a Mach 5 flow

Separation induced by impinging shock is a fundamental feature in supersonic and hypersonic flows; however, it is difficult to predict the pressure plateau due to a limited theoretical understanding of the effect of impinging shock strength. In this study, the evolution of the separation configuration and pressure distribution with changes in impinging shock angle is examined, and a theoretical equation for predicting the pressure plateau based on minimum entropy production is proposed. For validation, an experimental device that can measure wall pressure in the separation region at high spatiotemporal resolution is developed, and schlieren visualization is employed to capture the flow structure. Accordingly, the fine characteristics of pressure distributions along the centreline of the separation region as well as the reattachment region induced by shock impingement at various angles ( $8.5^\circ$ to $30.5^\circ$ ) are obtained in a flow of Mach number 5 and Reynolds number ${\approx }1.4\times 10^7\ {\rm m}^{-1}$ . The experimental results agree well with the theoretical results; both indicate that the pressure distribution is strongly related to the impinging shock strength and that there is a critical flow deflection angle $\alpha ^\ast$ ( ${\approx }20.8^\circ$ for Mach 5). The pressure in the separation region grows nearly linearly with increasing impinging shock strength when the flow deflection angle of the impinging shock is less than $\alpha ^\ast$ ; the pressure stops growing and resides in a small range when the flow deflection angle is larger than $\alpha ^\ast$ . Therefore, the impinging shock strength should be considered a main factor when predicting the pressure plateau.

The Spatial Pattern Evolution of Rural Settlements and Multi-Scenario Simulations since the Initiation of the Reform and Opening up Policy in China

Since the inception of China’s reform and opening-up policy, the rapidly advancing process of urbanization and the primacy accorded to urban development policies have imparted increasingly profound ramifications on rural domains. Nonetheless, antecedent research has predominantly fixated on urban sprawl, overlooking the spatial metamorphosis of rural settlements and the prospective developmental trajectories within the policy paradigm. Consequently, this inquiry endeavors to scrutinize the evolution of the spatial configuration of rural settlements in She County from the advent of reform and opening-up (1980–2020) utilizing remote sensing data. In tandem, through scenario delineation and the utilization of the CLUE-S model, it aspires to prognosticate the evolving trends in the spatial arrangements of rural settlements in She County by 2035. The empirical findings divulge that (1) The temporal progression of rural settlement spatial configurations in She County over the preceding four decades can be delineated into two discernible phases. From 1980 to 2000, alterations in the number, extent, and spatial morphological attributes of rural settlements remained circumscribed. While the count of rural settlements registered a diminution (by 3), the aggregate extent experienced a marginal augmentation (by 8.45%), concomitant with a gradual gravitation towards regular boundaries, manifesting a stochastic distribution throughout the investigation expanse. Conversely, from 2000 to 2020, the quantity and extent of rural settlements in She County underwent a precipitous augmentation (92 and 36.37%, respectively), characterized by irregular peripheries. (2) The CLUE-S model achieved an overall precision of 0.929, underscoring its applicability in emulating fluctuations in rural settlements. (3) Within the new-type urbanization scenario, the cumulative expanse of rural settlements witnessed a decline of 35.36% compared to the natural development scenario, marked by substantial conversions into grassland and urban land usage. Furthermore, orchestrated planning and directive measures have propelled the consolidation of rural settlements in She County, engendering a more equitable and standardized layout. Under the aegis of the ecological conservation scenario, the total rural settlement area recorded a 0.38% reduction vis-à-vis the natural development scenario, primarily entailing competitive coexistence with arable land, grassland, and urban land usage in spatial terms.

Configuration Evolution of a Particle Raft with a Preprepared Crack Driven by the Diffusion of a Surfactant.

In the present study, the morphology evolution of a particle raft with a preprepared crack, which is caused by injecting the surfactant sodium dodecyl sulfate (SDS) into water, is demonstrated. Experimental results on the process of crack closure and configuration evolution are captured and are in excellent agreement with the numerical simulations. Then a surface diffusion model on SDS is proposed to quantify the detailed physical scenario. The surface diffusion factor is determined through the shooting method based on the experimental result of dynamic surface tension. As a result, the analytical solution for the SDS concentration distribution is given. The theoretical result on the dependence relationship between the profile shrinkage ratio and the time variable is consistent with the experimental result. At last, the relation between the initial surface tension difference of SDS and the profile shrinkage ratio is obtained in the light of experiments and dimensional analysis, and the two results are very close. These analyses provide a comprehensive understanding of the coupling between chemicals and mechanical behaviors of soft matter, and the modulation of defects in the particle raft provides some inspiration for engineering new devices at the microscale.

Three-dimensional magnetothermal evolution of off-centred dipole magnetic field configurations in neutron stars

ABSTRACT Off-centred dipole configurations have been suggested to explain different phenomena in neutron stars, such as natal kicks, irregularities in polarization of radio pulsars and properties of X-ray emission from millisecond pulsars. Here, for the first time, we model magnetothermal evolution of neutron stars with crust-confined magnetic fields and off-centred dipole moments. We find that the dipole shift decays with time if the initial configuration has no toroidal magnetic field. The decay time-scale is inversely proportional to magnetic field. The octupole moment decreases much faster than the quadrupole. Alternatively, if the initial condition includes strong dipolar toroidal magnetic field, the external poloidal magnetic field evolves from centred dipole to off-centred dipole. The surface thermal maps are very different for configurations with weak B = 1013 G and strong B = 1014 G magnetic fields. In the former case, the magnetic equator is cold while in the latter case, it is hot. We model light curves and spectra of our magnetothermal configurations. We found that in the case of cold equator, the pulsed fraction is small (below a few per cent in most cases) and spectra are well described with a single blackbody. Under the same conditions, models with stronger magnetic fields produce light curves with pulsed fraction of tens of per cent. Their spectra are significantly better described with two blackbodies. Overall, the magnetic field strength has a more significant effect on bulk thermal emission of neutron stars than does the field geometry.

Evolution of Ni coordination configuration during one-pot pyrolysis synthesis of Ni-g-C3N4 single atom catalyst

In this paper, the unclear Ni atom coordination structure evolution in one-pot pyrolysis method synthesizing Ni single atom catalyst using graphitic carbon nitride as support (Ni-g-C3N4) was deeply discussed. In-situ X-ray absorption fine structure spectra and other assisted methods were used to characterize the structural evolution. The results demonstrate that the pyrolysis process can be divided into three stages. In the first stage from room temperature to 183 °C (Stage I), the NiCl2⋅6H2O was mixed with the supporting material (dicyandiamide) to form the precursor with Ni-(H2O)6 octahedral coordination configuration. In the second stage from 183 to 350 °C (Stage II), the H2O molecules have been removed and the supporting material was converted to melamine. The melamine molecules were polycondensed to melem during 308–350 °C. The intermediates labeled Ni-melamine and Ni-melem was formed with Ni-N4 planar quadrilateral coordination configuration. In the third stage from 350 to 600 °C (Stage III), the supporting material (melem) was gradually converted to g-C3N4, and the Ni-N4 coordination configurations were replaced by Ni-N6 planar hexagon coordination configuration one by one. The three Ni coordination configurations were further confirmed by Reverse Monte Carlo simulations and ab initio calculations.

Role of inherent anisotropy in infiltration mechanism of suffusion with irregular granular skeletons

Suffusion, the process of particle migration and clogging within porous media, exerts a remarkable impact on various natural and engineered systems. Properties of the coarse-grained skeletons are crucial during suffusion, while the influence of the inherent anisotropy remains insufficiently explored. In this study, numerical model using the coupled computational fluid dynamics and the discrete element method (CFD-DEM) is performed to simulate the suffusion evolution of different fabric anisotropy configurations under controlled flow conditions. Granular skeletons are generated considering different initial rotational degrees of freedom (RDoFs) and orientations of irregular coarse particles, based on which the motion mechanism of migratory fines is investigated. The infiltration process is quantified by multi-scale parameters, including particle distribution, velocity evolution, visualization of pores and throats, force network, contact statistics and anisotropic characteristics. The results illustrate the non-negligible influence of inherent anisotropy on pore structure, consequently impacting the motion behavior of fine particles and the stress transmission within the granular skeletons. Such insights will contribute to advancing a fundamental understanding of suffusion, which enables the development of effective strategies for predicting and controlling in geotechnical and environmental engineering catastrophes.

Leveraging polymer modeling to reconstruct chromatin connectivity from live images

Chromosomal dynamics plays a central role in a number of critical biological processes, such as transcriptional regulation, genetic recombination, and DNA replication. However, visualization of chromatin is generally limited to live imaging of a few fluorescently labeled chromosomal loci or high-resolution reconstruction of multiple loci from a single time frame. To aid in mapping the underlying chromosomal structure based on parsimonious experimental measurements, we present an exact analytical expression for the evolution of the polymer configuration based on a flexible-polymer model, and we propose an algorithm that tracks the polymer configuration from live images of chromatin marked with several fluorescent marks. Our theory identifies the resolution of microscopy needed to achieve high-accuracy tracking for a given spacing of markers, establishing the statistical confidence in the assignment of genome identity to the visualized marks. We then leverage experimental data of locus-tracking measurements to demonstrate the validity of our modeling approach and to establish a basis for the design of experiments with a desired resolution. Altogether, this work provides a computational approach founded on polymer physics that vastly improves the interpretation of in vivo measurements of biopolymer dynamics.

Strategic closed-loop supply chain configuration in the transition towards the circular economy of EV batteries: an evolutionary analytical framework

PurposeThis study advocates the importance of taking an evolutionary perspective in the strategic configuration of closed-loop supply chains (CLSC) in the transition to a circular economy. Building on the supply chain management and industrial dynamics research domains, an evolutionary analytical framework was developed and applied in the empirical context of the ongoing industrial transition to e-mobility.Design/methodology/approachThis study is designed as an in-depth exploratory case study to capture the multi-layer dynamic complexities and their interplay in CSLC development. The empirical investigation was based on two-year interactions between the authors and various departments in a leading European heavy vehicle manufacturer. The proposed evolutionary analytical framework was used for investigating the dynamics of four CLSC configurations through ten possible trajectories.FindingsThe findings demonstrate that the evolution of each CLSC configuration comes with multiple challenges and requirements and point out the necessity for the co-development of technologies, product design and production, and infrastructure through long-term relationships among key supply chain actors. However, this evolutionary journey is associated with multiple dilemmas caused by uncertainties in the market and technology developments. All these factors were properly captured and critically analyzed, along with their interactions, thanks to the constructs included in the proposed evolutionary analytical framework.Research limitations/implicationsThe proposed evolutionary framework is applicable for examination of SC transformation in the context of market and technology development, and is particularly relevant for transitioning from linear SC to CLSC. The framework offers a single actor perspective, as it does not directly tackle dynamics and effects of actions taken by SC actors.Practical implicationsThe developed framework can support SC managers in identifying, framing, and comparing alternative strategies for CLSC configuration in the transition process.Originality/valueThis study proposes the framework for understanding and guiding the evolutionary process of CLSC development. Its uniqueness lies in the integration of concepts from innovation and evolutionary theories coming from industrial dynamics and SCM literature streams.

Repair of embrittlement induced by different hydride configurations by dissolving partial hydrides using pulsed electric current

The sudden brittle fracture of Ti, Zr and other metals caused by brittle hydride phase usually depends on the hydride network that provides the crack initiation and propagation path. Common hydride networks include continuous hydride configuration and grain boundary hydride configuration. In this study, pulsed electric current is used to effectively repair the embrittlement caused by continuous hydride configuration and grain boundary hydride configuration in pure titanium. The elongation of pure titanium with hydride configuration increased from 10% to about 20% after pulsed electric current treatment, with a certain degree of recovery of ultimate tensile strength. This is due to the dissolution of partial hydride after pulsed electric current treatment, and the hydride configuration is destroyed. Considering the introduction of pulsed electric current, hydride configuration in pure titanium is thermodynamically unstable, and the electromigration effect in kinetics also accelerates desorption of hydrogen atoms. The evolution of hydride configuration and desorption of hydrogen atoms are beneficial to the recovery of mechanical properties of hydrogenated pure titanium. In this study, the problem of hydride embrittlement caused by different hydride configurations in pure titanium was effectively repaired by pulsed electric current, which provided a new pathway and solution for dealing with the hydride induced embrittlement.

Conceptual review and optimization of liquid air energy storage system configurations for large scale energy storage

Among energy storage systems, Liquid Air Energy Storage (LAES) is attractive because of high energy density, ease of being scaled up, absence of geographical constraints, mature technology and use of safe materials/working fluids. This work presents a critical review of LAES system configurations in the literature to identify the criteria behind their conceptual development. The goal is achieved following the HEATSEP methodology, which allowed identifying a common thread in the evolution of all LAES configurations in the literature based on very few layouts, named “basic configurations”. The optimization of these few layouts, taking into account all possible internal heat transfers, provides a unique and comprehensive overview of existing configurations in spite of their seemingly great complexity. This picture clearly indicates the link between topology and performance improvement and provides insight into the limits of the maximum possible performance gain over the existing literature. The optimal results show that the margin for improvement is quite narrow. In the case of a complete thermal integration between charge and discharge phases with the addition of Organic Rankine Cycle system a gain from 61.9 % to 64.3 % is obtained over the best performing configuration in the literature.

On the configuration evolution of soft filaments under combined tension and torsion

On the configuration evolution of soft filaments under combined tension and torsion

Solvent extraction of superfine pulverized coal. Part 3. Small angle X-ray scattering characterization

Because of the unique physicochemical textures induced by reduced particle size, superfine pulverized coal presents attractive characteristics in different utilization processes, including solvent extraction. In this work, the synchrotron radiation-based small angle X-ray scattering (SAXS) with high precision was used to quantitatively characterize all the products during the coal extraction process, including raw coal, extract, and residue. In addition, the evolutions of pore structures (solid state) and aggregate configurations (liquid state) were focused on. The results show that the fractal dimensions of pore surfaces are mainly related to the pore sizes and corresponding quantity distributions. When the particle size is less than 14 μm, the comminution induced mechanical effect on the pore surface gradually changes from impact to polish during the superfine grinding. Additionally, the fractal dimension decreases with the decline of particle size and ash content, whilst increases for the lower ranked coals. As for the extraction process, the extraction effect of tetrahydrofuran on anthracite coal is relatively better, while pyridine is more effective for bituminous coal. The diverse driving force caused by particle size effect leads to different radii of the gyration of the extracted aggregates, indicating the selected bituminous coal has active sites that are susceptible to reacting with aromatic compounds, while anthracite has a large number of active sites that accept electrons. Finally, the surface fractal dimension of the extraction residue declines about 2% and 4% for HN and NMG coal respectively, and the decreasing trend declines for larger coal particles. Interestingly, this decreasing trend of bituminous coal is more evident, which indicates the pore surface of bituminous coal is easier to react with solvent. The research sheds light on thoroughly depicting the pore structure of coal and residue at a molecular level, which promotes a better understanding of the solvent extraction mechanisms. The results also provide a new perspective for constructing more comprehensive coal molecular models in the future.

Confined magnetic vortex motion from metal-organic frameworks derived Ni@C microspheres boosts electromagnetic wave energy dissipation

Magnetic domain structure plays an important role in regulating the electromagnetic properties, which dominates the magnetic response behaviors. Herein, unique magnetic vortex domain is firstly obtained in the Ni nanoparticles (NPs) reduced from the Ni-based metal-organic frameworks (MOFs) precursor. Due to both the high symmetry spheres and boundary restriction of graphited carbon shell, confined magnetic vortex structure is generated in the nanoscale Ni core during the annealing process. Meanwhile, MOFs-derived [email protected] assembly powders construct special magnetic flux distribution and electron migration routes. MOFs-derived [email protected] microspheres exhibit outstanding electromagnetic (EM) wave absorption performance. The minimum reflection loss value of [email protected]–V microspheres with vortex domain can reach −54.6 ​dB at only 2.5 ​mm thickness, and the efficient absorption bandwidth up to 5.0 ​GHz at only 2.0 ​mm. Significantly, configuration evolution of magnetic vortex driven by the orientation and reversion of polarity core boosts EM wave energy dissipation. Magnetic coupling effect among neighboring [email protected] microspheres significantly enhances the magnetic reaction intensity. Graphitized carbon matrix and heterojunction Ni–C interfaces further offer the conduction loss and interfacial polarization. As result, MOFs-derived [email protected]–V powders display unique magnetic vortex, electronic migration network, and high-performance EM wave energy dissipation.

Low cycle fatigue behavior of 316LN stainless steel: Effects of temperature, strain rate and strain amplitude

Continuous and interrupted LCF tests were conducted to reveal the effects of temperature, strain rate and strain amplitude on the LCF behavior of a nitrogen-alloyed 316LN stainless steel. The cyclic hardening and softening behavior at high and low strain amplitudes were elaborately elucidated based on the method of stress decomposition and characterization of dislocation configuration evolution. In addition, the dominant damage mechanism responsible for the different cracking modes under various loading conditions was determined based on the observations of fracture surface and secondary cracks on the longitudinal section.

Contact dynamic analysis of tether-net system for space debris capture using incremental potential formulation

An efficient computational method is proposed to combine the discrete differential geometry (DDG) method with the multi-dimensional incremental potential (IP) formulation to simulate the contact dynamics between a shooting net and a defunct satellite. The geometrically nonlinearity of the elastic net is described using the DDG method, which discretizes the flexible net into multiple nodes and connected edges. The internal elastic forces and the associated Jacobians are derived analytically. The multi-dimensional incremental potential formulation is used to achieve the intersection-free condition during the physical collision between deformable tether-net and rigid space debris. The smooth IP barrier functional constructed for contact simulation is differentiable, such that the nonlinear elastodynamic system can be robustly solved through a fully implicit time-marching scheme. Our numerical approach is first applied to simple examples, and demonstrating its effectiveness in dealing with non-penetration contacts of elements with different dimensions, such as ‘edge-to-edge’ and ‘edge-to-surface’. Next, the dynamic interaction between the deploying net and defunct satellite is analysed. A parameter sweep is performed with our robust and efficient simulator to show the configuration evolution of the net shot from different relative locations of the target object. Our numerical results can provide an optimal deployment strategy for tether-net capture systems during the active debris removal missions.

Evolution of Diversity in the Auditory Papillae of Reptiles

The independent origins of middle ears in testudinates, lepidosaurs, and archosaurs in the Triassic led to lineage-specific developments in their auditory epithelia. In comparison to the inferred ancestral state, little changed in testudinates, but archosaurs and most lepidosaurs evolved longer, differentiated auditory papillae. In archosaurs, sensory hair cells specialized across and along the papillae, resulting in mainly sensory tall hair cells and mainly mechanically active short hair cells. Crocodilians have 5 mm-long papillae, but relatively low upper frequency limits at around 4 kHz. Avian papillae are mostly 3 to 5 mm in length, being shorter in small species; in owls they exceptionally reach almost 12 mm and have an upper limit of above 10 kHz. Lepidosaurs retained the ancestral papilla as a low-frequency responsive area with one type of hair cell, but most added newly evolved areas (of max. 2 mm length) consisting of oppositely oriented hair cells responding to frequencies above 1 kHz. Initially, these areas flanked both ends of the ancestral area and were redundant in their responses to sound. The evolution of specific configurations in most families eliminated this redundancy, but the paths taken resulted in diverse anatomies that show high degrees of family specificity. Despite these differences, the high-frequency hearing limit of lepidosaurs rarely exceeds 5 kHz.

Particle acceleration with magnetic reconnection in large-scale RMHD simulations – I. Current sheet identification and characterization

ABSTRACT We present a new algorithm for the identification and physical characterization of current sheets and reconnection sites in 2D and 3D large-scale relativistic magnetohydrodynamic numerical simulations. This has been implemented in the pluto code and tested in the cases of a single current sheet, a 2D jet, and a 3D unstable plasma column. Its main features are (i) a computational cost that allows its use in large-scale simulations and (ii) the capability to deal with complex 2D and 3D structures of the reconnection sites. In the performed simulations, we identify the computational cells that are part of a current sheet by a measure of the gradient of the magnetic field along different directions. Lagrangian particles, which follow the fluid, are used to sample plasma parameters before entering the reconnection sites that form during the evolution of the different configurations considered. Specifically, we track the distributions of the magnetization parameter σ and the thermal to magnetic pressure ratio β that – according to particle-in-cell simulation results – control the properties of particle acceleration in magnetic reconnection regions. Despite the fact that initial conditions of the simulations were not chosen ‘ad hoc’, the 3D simulation returns results suitable for efficient particle acceleration and realistic non-thermal particle distributions.

Giant Switchable Persistent Photoconductivity in Soft Chemistry Reduced SrTiO3

AbstractHigh tunability of photoconductivity is highly desired for applications in optical memories, sensors, and bioelectronics. Recently, room temperature persistent photoconductivity (PPC) in SrTiO3 (STO) has been revealed and has attracted great attention. However, reversible switching of the PPC in STO with a large on/off ratio remains challenging to date. Here, a giant switchable PPC in soft chemistry reduced STO is reported. An initial insulator‐to‐metal transition with on/off ratio up to 7 orders of magnitude is observed and about 5 orders of magnitude transition is found to be reversible. Via nuclear magnetic resonance measurements, it is uncovered that such unusual PPC is driven by the generation of excess carriers accompanied with a configuration evolution of the incorporated hydrogen from hydridic HO+ to protic Hi+ upon illumination. The work demonstrates giant switchable PPC transition in soft chemistry reduced perovskite oxides, providing a new platform for pursuing high performance sensors and nonvolatile optoelectronic memory devices.

Temperature‐induced magnetic compensation and negative magnetization in a cluster spin glass Gd2Co0.5Mn1.5O6 system

AbstractExperiments for orthorhombic double perovskite Gd2Co0.5Mn1.5O6 revealed intrinsic effects of magnetic compensation characterized by M(Tcomp) = 0 at Tcomp = 20 K and negative magnetization depicted by M(T) < 0 under positive magnetic fields, which were experimentally investigated by different protocols of direct current magnetization measurements. Compared to Gd2CoMnO6, the excessive ratio of Mn in Gd2Co0.5Mn1.5O6 promotes the antisite disorder and preferably generates magnetic clusters owing to the intrinsic inhomogeneity. The clusters exhibit spin glass (SG) properties as demonstrated by alternating current susceptibility and aging measurements. A possible physical mechanism for evolution of the spin configuration with temperature is proposed. The effects of magnetic compensation and negative magnetization are attributed to the negative exchange coupling among the abundant ferromagnetic clusters. The additional pinning force provided by the cluster SG is an essential factor to prevent the flipping of the spins from aligning with the applied magnetic field.