Evolution Rules Research Articles

Experimental Study on the Shear Properties of Soil around Piles with Permeation Grouting

While post-grouting is frequently reported to improve the engineering performance of piles, the shear strength of the soil around piles is not well understood. To investigate the strengthening mechanism of soil around piles with permeation grouting, laboratory tests were carried out on homemade cement soil from the aspects of shear strength and microstructure characteristics. The evolution rule of the shear stress–shear displacement curve of grouting soil with different cement contents was analyzed, and the influence of grouting parameters on shear strength was explained. A composite exponential model describing the shear stress and shear displacement of permeation grouting silty clay was established. Furthermore, the influence of different cement content on changes in the microstructural characteristic parameters of the soil around piles was studied. The results show that penetration grouting has a positive effect on improving the shear strength of the soil around piles, and the failure mode of silty clay changed from elastic–plastic failure to brittle failure after grouting. Permeation grouting makes the particle structure denser, which limits the changes in pore arrangement and distribution. The shear failure of the soil around piles under permeation grouting obeys the Mohr–Coulomb criterion of failure. It is recommended to increase the grout diffusion radius during construction, considering the reinforcement effect of permeation grouting on the soil around piles.

Research progress of synthesis of high-performance perovskites and its derivatives based on polyhedral distortion

Corner-shared coordination polyhedral crystals (CSCPCs) represented by perovskites have unique and various properties in optics, electrics, and magnetism, leading to their broad applications such as in serving as ferroelectric material, fast ionic conductors, and electro/photo-catalysts. However, the excellent properties are owned only by a very small fraction of CSCPS phases. How to obtain such phases through structural operation has always been a research hotspot and a bottleneck in related fields. Herein, we review the recent research progress of the synthesis of high-performance CSCPC materials from the perspective of phase structure, in order to clarify the intrinsic rules of phase evolution and reveal the mechanism behind the phase manipulation. We first systematically summarize the types of polyhedra and crystal frameworks in CSCPCs and classify the polyhedral distortions as three main types, i.e. cation displacements, polyhedral rotations, and deformations. Based on that, we further analyze and conclude different material synthesis methods. We find that most traditional synthesis methods rely on the phase transitions induced by the change of external physical conditions at a macroscopic level, such as composition, temperature, and pressure. Recently, there was an emerging synthesis method focusing on the microscopic manipulation of polyhedral geometry and topology, such as phase constructions according to tolerance-factor and substrate-proximity effects. The macroscopic synthesis methods and the microscopic synthesis methods share the same phase manipulation mechanism: making crystals transit into the structure-specified phases by inducing polyhedral distortions. The only difference is that the latter is more target-oriented, but its applications are currently limited to octahedral coordination tilt/rotation systems. Expanding its application scope is still a challenge. In addition, we propose two aspects that may be useful in optimizing the synthesis method: one is to clarify the origin of induced distortions and the interaction between different distortions, and the other is to customize the guidelines based on computer science. We hope that the research progress reviewed in this article can provide some valuable references and inspirations for designing and synthesizing the high-performance CSCPC materials.

Dynamic decision in a retailer-led closed-loop supply chain under altruistic preference

The dynamic decision-making strategies on the altruistic behavior of a manufacturer, a retailer, a third-party recycler and tripartite in the closed-loop supply chain (CLSC) are researched. We respectively considered four altruistic preference models of differential game and Bellman theory that contrasted and analysed the wholesale price and transfer payment price strategies of the manufacturer, the unit profit of products strategy of the leader retailer, the recycling price and the investment in recycling efforts strategies of the third-party recycler and the recycling rate of used products and the value functions of members. The numerical analysis further analyses the rule of the time evolution of CLSC performance under four altruistic preference models. In this paper we can see that: altruistic preference has an optimistic influence to our society; the manufacturer's altruistic preference can effectively lessen the duple marginal influence on the CLSC while increase the rest of consumers; in contrast, tripartites’ altruistic preference model has the optimal outcome of the CLSC, which can bring about both economic and environmental benefits.

Research on the Dynamic Evolution of Export Product Quality of Chinese Industrial Enterprises: Based on the Dual Dimensions of Quantitative Change and Qualitative Change

Most of the existing studies on the dynamic evolution of Chinese export product quality have been analyzed from an empirical perspective, lacking theoretical investigation of its intrinsic evolution rules. Therefore, this paper defines the connotation of export product quality improvement (quantitative change of export product quality) and export product quality upgrading (qualitative change of export product quality), analysis the connection and difference between them, and constructs the corresponding evaluation indexes by referring to the rules of quantitative change and qualitative change in materialistic dialectics. Based on the data of Chinese industrial exporters from 2000 to 2013, the dynamic evolution of export product quality was measured statistically. The results of the research are as follows: (1) the overall export product quality of Chinese industrial enterprises showed a fluctuating upward trend. Among them, the export product quality of foreign-invested enterprises, large enterprises, and enterprises in the eastern region is higher. (2) From the dimension of quantitative change, the export product quality of Chinese industrial enterprises improved in 2001, 2003-2005, 2007, and 2011-2012, and there are some differences in the improvement of export product quality among enterprises of different ownership, scale, and regions. (3) From the dimension of qualitative change, the number of enterprises that achieve export product quality upgrading is increasing, and the mean and level of export product quality upgrading are improving. Among them, the export product quality upgrading of state-owned enterprises, large enterprises, and enterprises in the western region is higher.

Structural predictions of three medium-sized thiolate-protected gold nanoclusters Au44(SR)30, Au56(SR)32, and Au60(SR)34.

The knowledge of structural evolution among thiolate-protected gold nanoclusters is not only helpful for understanding their structure-property relationship but also provides scientific evidence to rule-guided structure predictions of gold nanoclusters. In this paper, three new atomic structures of medium-sized thiolate-protected gold nanoclusters, i.e. Au44(SR)30, Au56(SR)32, and Au60(SR)34, are predicted based on the grand unified model and ring model. Two structural evolution rules, i.e., Au44(SR)28 + [Au12(SR)4] → Au56(SR)32 + [Au12(SR)4] → Au68(SR)36 and Au44(SR)30 + [Au8(SR)2] → Au52(SR)32 + [Au8(SR)2] → Au60(SR)34 + [Au8(SR)2] → Au68(SR)36, are explored. The generic growth patterns underlying both sequences of nanoclusters can be viewed as sequential addition of four and three highly stable tetrahedral Au4 units on the cores, respectively. In addition, density functional theory calculations show that these three newly predicted gold nanoclusters have very close formation energies with their adjacent structures, large highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) gaps, and all-positive harmonic vibration frequencies, indicating their high stabilities.

Research on digital sharing mechanism of agricultural science and technology resources considering collaborative innovation capability

The digital sharing of agricultural scientific and technological resources is the key to promoting agricultural scientific and technological innovation. Explore the strategic mechanism for the digital sharing of agricultural scientific and technological resources, reveal the law of their behavioral evolution, and provide theoretical guidance for the practice of digital sharing of agricultural science and technology resources. Introducing the perspective theory of perceived utility to replace expected utility, constructing a stochastic evolutionary game model for the sharing parties and demand parties of agricultural science and technology resources, analyzing the dynamic evolution rules of both sides of resource sharing, and analyzing the key factors affecting the stability of agricultural science and technology resource sharing through numerical simulation.

The ensemble of gene regulatory networks at mutation-selection balance.

The evolution of diverse phenotypes both involves and is constrained by molecular interaction networks. When these networks influence patterns of expression, we refer to them as gene regulatory networks (GRNs). Here, we develop a model of GRN evolution analogous to work from quasi-species theory, which is itself essentially the mutation-selection balance model from classical population genetics extended to multiple loci. With this GRN model, we prove that-across a broad spectrum of selection pressures-the dynamics converge to a stationary distribution over GRNs. Next, we show from first principles how the frequency of GRNs at equilibrium is related to the topology of the genotype network, in particular, via a specific network centrality measure termed the eigenvector centrality. Finally, we determine the structural characteristics of GRNs that are favoured in response to a range of selective environments and mutational constraints. Our work connects GRN evolution to quasi-species theory-and thus to classical populations genetics-providing a mechanistic explanation for the observed distribution of GRNs evolving in response to various evolutionary forces, and shows how complex fitness landscapes can emerge from simple evolutionary rules.

Maximizing the Influence Spread in Social Networks: A Learning-Automata-Driven Discrete Butterfly Optimization Algorithm

Influence maximization aims at the identification of a small group of individuals that may result in the most wide information transmission in social networks. Although greedy-based algorithms can yield reliable solutions, the computational cost is extreme expensive, especially in large-scale networks. Additionally, centrality-based heuristics tend to suffer from the problem of low accuracy. To solve the influence maximization problem in an efficient way, a learning-automata-driven discrete butterfly optimization algorithm (LA-DBOA) mapped into the network topology is proposed in this paper. According to the LA-DBOA framework, a novel encoding mechanism and discrete evolution rules adapted to network topology are presented. By exploiting the asymmetry of social connections, a modified learning automata is adopted to guide the butterfly population toward promising areas. Based on the topological features of the discrete networks, a new local search strategy is conceived to enhance the search performance of the butterflies. Extensive experiments are conducted on six real networks under the independent cascade model; the results demonstrate that the proposed algorithm achieves comparable influence spread to that of CELF and outperforms other classical methods, which proves that the meta-heuristics based on swarm intelligence are effective in solving the influence maximization problem.

Theoretical analysis on the Barrow holographic dark energy in the DGP braneworld

This paper further studies the cosmological evolution and geometry diagnosis of Barrow holographic dark energy (BHDE) in the DGP braneworld, specifically, by choosing the interaction between dark energy and dark matter item. [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text] are discussed in the case of no interaction and four different interactions, the evolution laws of energy density parameters, deceleration parameters and EOS (equation of state) parameters of Barrow holographic dark energy. The results show that the Barrow holographic dark energy in the DGP braneworld conforms to the current cosmic evolution rule, already achieved the universe main ingredients from matter to the transition of energy, and explains the problem of cosmic acceleration. Further, in order to distinguish between the model and [Formula: see text]CDM model, this paper also geometrically diagnoses the model with the two ways of Statefinder hierarchy and Om[Formula: see text]. From their respective evolution image you can see, these two kinds of diagnosis methods can not only distinguish different from [Formula: see text]CDM model, but also can intuitively reflect the coupling parameters that can significantly affect the dark energy model.

Analyzing Express Revenue Spatial Association Network’s Characteristics and Effects: A Case Study of 31 Provinces in China

In recent years, China’s express delivery industry has experienced significant regional differences in income, which may endanger the sustainable development of the economy and affect the sustainable development of society. To study the development setup and influencing factors of the express delivery industry in various regions of China, based on the income data of provincial express delivery, we constructed a spatial correlation network of provincial express revenue in China using the social network analysis method and analyzed its network characteristics and evolution rules. Additionally, the relationship between network structure parameters and express revenue was tested using the spatial Durbin model. The results reveal that the spatial correlation network of China’s provincial express revenue changes from decentralization to agglomeration, and the connection between the express industry in each province is constantly strengthened. The provinces in the eastern coastal areas exhibit a higher degree of centrality and effective scale in the network, and the limit system is smaller, which indicates that these provinces have higher importance and control ability in the network. Simultaneously, a moderating effect exists between network structure parameters and express income, indicating that network structure parameters affect express income through human capital input. This study provides theoretical research and empirical support to promote the coordinated and sustainable development of the express delivery industry.

Study on friction and wear properties of cast iron material in line contact condition based on free abrasive grinding experiment

In order to study the friction and wear properties of cast iron in free grinding environment under the condition of line contact, this paper presented a new method to calculate the friction coefficient by measuring the friction torque. Through the self-developed free abrasive grinding experimental device in line contact condition, this work carried out friction and wear experiment with relative speed, load, abrasive particle diameter, and abrasive mass fraction as process parameters, and studied the evolution rules of friction coefficient and wear amount of cast iron materials under different process parameters. Based on the response surface method Box-Behnken experimental design, the significance of the experimental results was analyzed, and the prediction model of the friction coefficient and wear amount of cast iron was established. According to the significance of the prediction model, the influence degree of each process parameter on the friction coefficient and wear amount was revealed. The results showed that under the action of free abrasive, the friction coefficient of cast iron material in line contact with GCr15 was between 0.18 and 0.35. When the experimental time was 1.5 h, the removal amount of cast iron material was between 20 and 65 mg, which is significantly increased compared with that without abrasive and the wearing capacity of cast iron increased with the increase of relative speed, load, abrasive particle diameter, and abrasive mass fraction. The friction coefficient had a negative correlation with relative speed, and a positive correlation with abrasive particle diameter and abrasive mass fraction. With the increase of load, the change of friction coefficient decreased first and then increased. The influence degree of each process parameter on the friction coefficient and wear amount of cast iron material: the particle diameter and relative velocity of abrasive were relatively significant, the abrasive mass fraction was the second, and the load was the smallest. Through random experiments, the prediction model of friction coefficient and wearing capacity were verified to be highly accuracy, and could be used to predict the friction and wear performance parameters of cast iron in the process of free grinding under the condition of line contact. It provided a certain theoretical basis for the friction and wear behavior of cast iron as a grinding tool material in the grinding process.

Acoustic Emission Test of Marble Powder Concrete

Uniaxial compression tests were carried out based on acoustic emission technology to study the rule and process of the damage evolution of marble powder concrete (MPC) under compression. The fracture characteristics of MPC are examined by analyzing the variation characteristics of acoustic emission signal parameters. The damage evolution model of MPC is established based on the characteristic parameters. The results showed that the strength loss rate of MPC decreased with the curing time, and the maximum strength loss rate of 28 d was 6.2% when the substitution percentage was 15%. According to the analysis of acoustic emission parameters, the compression failure process of MPC can be divided into three stages, the acoustic emission activity is higher in the early stage of loading, the relative stress during critical instability failure is reduced, and the substitution percentage is reduced by 4.2% at 15%. MPC is mainly fractured by tensile failure. With the increase in marble powder substitution percentage, the proportion of tensile mode cracks in stages I and II decreased. The proportion in stage III showed an increasing trend, and the failure characteristics gradually changed from brittleness to ductility. The fluctuation amplitude of the b-value increased with the substitution percentage, and the highest volatility was 18.5% when the substitution percentage was 15%. The crack propagation behavior gradually changed from stable growth to unstable growth. When the substitution percentage is lower than 15%, the damage development of MPC in the middle of stress (relative stress 20~70%) is relatively slow, and the damage development is accelerated in the late stress stage.

Bounding surface rotational hardening model for overconsolidated clay accounting for evolving fabric anisotropy

AbstractSoil is inherently anisotropic owing to the sedimentation process under gravity and is generally under anisotropic stress state in the field. To reflect the influence of anisotropic consolidation, rotational hardening (RH) is favorably used in constitutive models, mimicking in‐situ stress conditions. However, most of the existing models do not account for the inherent anisotropy of clays under isotropic stress state as well as the interplay between the fabric and loading direction, and the corresponding initial yield surface is assumed to be oriented along the hydrostatic axis. Furthermore, as the rotational angle is usually deemed as the clayed soil's anisotropy measure, a critical yield surface without rotation appears to contradict the highly anisotropic fabric at critical state. In this study, an anisotropic bounding surface model that incorporates RH and fabric anisotropy is formulated to simulate the behavior of overconsolidated (OC) clay subject to different consolidation histories, while addressing the aforementioned inconsistency issue. During the loading process, both fabric anisotropy and rotational angle evolve continuously based on their respective evolution rules. Fabric anisotropy evolves to the critical state when the rotational angle returns to zero, satisfying the anisotropic critical state theory (ACST). In addition, the model employs an anisotropic elasticity to consider the influence of the initial fabric at a low‐stress level. The predictive capacity of the model can be demonstrated by simulating several compression and extension tests on clay over a wide range of overconsolidation ratios (OCRs) and anisotropic consolidation stress ratios under both drained and undrained conditions.

A Coupling Model for Tribodynamic Behavior of the Hydroviscous Flexible Drive With Consideration of Saucer-Warping Deformation

An improved coupling model, including the dynamic transmission characteristics and thermal deformation behavior of the disks, is developed for predicting the tribodynamic behavior of the hydroviscous flexible drive under realistic driving conditions. The present work overcomes previous limitations by incorporating transient saucer-warping deformation due to friction heat. Dynamic parameters because of the saucer-warping angle effects, including the film thickness and total torque, are analyzed based on an iterative method. Axial deformation, radial deformation, and saucer-warping angle are simultaneously obtained by finite-element analysis. Based on the comparison with the experimental data, the performance of the coupling model is found satisfactory. The results show that the increase of the saucer-warping angle is favorable for the improvement of flexible transmission characteristics. As a result of the saucer-warping angle effects, significant reduction of the inlet flow rate will lead to the reduction of maximum total torque. Neither radial displacements nor axial displacements are good enough to predict the evolution rule about friction heat during the engagement process. Based on the combined effects of equivalent film thickness and real frictional area, the torque results for the deformed disks are larger than those when the disks are parallel. The saucer-warping angle effect begins to dominate the total torque especially when the film thickness reaches its minimum. The model developed in this research may become an efficient alternative model for the prediction of flexible transmission behavior of the real driving system.

Multiscale modeling for dynamic compressive behavior of polymer bonded explosives

The impact damage behavior of polymer bonded explosives (PBXs) is critical to ensure the safety of explosive systems. PBX 1314 (60 wt% RDX, 16 wt% aluminum, and 24 wt% HTPB) is a popular propellant owing to its characteristics of high energy density and low sensitivity. In this study, the compressive damage evolution rules and the strain rate effect of PBX 1314 were investigated by using a multiscale method. To acquire damage evolution data during loading, a finite element model based on real crystal morphology, with a cohesive zone model (CZM) for describing the damage, was developed. A novel hybrid/inverse optimization strategy was developed to calibrate the cohesive parameters of PBX 1314, and the accuracy of the parameters was verified basis experimental results. Using an as-developed bilinear model, the shift of damage pattern with the variation of strain rate was observed, and the nonlinearity of the stress–strain curve was presented at the mesoscale. The crack parameters and distribution of damaged elements in each mesoscopic component were acquired to quantitively characterize the strain rate dependence of PBX 1314, and the mechanism of crack propagation and the shift of damage mode under various strain rates was illustrated. The findings of this study provide insights for understanding the nonlinearity of macroscopic mechanical behavior and the influence of strain rate on the mesoscopic damage mode of PBXs with high binder content.

Towards a Model of Urban Evolution—Part III: Rules of Evolution

This paper develops a formal model of urban evolution in terms of (1) sources of variations; (2) principles of selection; and (3) mechanisms of retention. More specifically, regarding (1) it defines local and environmental sources of variation and identifies some of their generative processes, such as recombination, migration, mutation, extinction, and transcription errors. Regarding (2), it outlines a series of selection processes as part of an evolutionary ecology of urban forms, including density dependence, scope dependence, distance dependence, content dependence, and frequency dependence. Regarding (3), it characterizes retention as a combination of absorption and restriction of novel variants, defines mechanisms by which these can occur, including longevity, fidelity, and fecundity, and specifies how these processes issue in trajectories define by properties such as stability, pace, convergence, and divergence. A conclusion reviews the effort and looks forward to computer simulation and data-driven applications, as well as focused theoretical extensions of parts of the model. This paper builds on Parts I and II and is part of the Urban Genome Project, about which more information can be found here.

Weight distributions of American domestic passenger air transportation networks

The scale-free features widely concerned by previous weighted network models seemed to not be the best choice to describe the link weight distributions of passenger air transportation networks. In this paper, by introducing an exponent α to the weight evolution rule of the earliest weighted model, and considering the spatial constraints of two-dimensional distances on linking probability, we have conducted rigorous analyses leading to the exponentially truncated power-law distribution for weights: , where A and B are parameters, α 1. The theoretical expression is consistent with the empirical results of the American domestic passenger flight records from 1995 to 2020. The model would be applicable to different air transportation systems and to problems in other fields.

A gradient descent direction based-cumulants method for probabilistic energy flow analysis of individual-based integrated energy systems

This study presents an individual-based model of heterogeneous integrated energy systems, which is composed of sub-energy system individuals and coupling individuals. Different evolution rules are depicted within one individual to form an accurate model of a complex system. Based on the model, a gradient descent direction iterative method (GDDM) is proposed for energy flow calculation of integrated energy systems to improve its convergence performance. Furthermore, a GDDM-based cumulants method (GDDM-CM) is presented to analyse the probabilistic energy flow distribution throughout the system. To verify the effectiveness of the proposed method, simulation studies have been undertaken in a modified complex integrated energy system. The results show that GDDM performs better than non-gradient descent method (NGDM). It converges faster and is insensitive to the initial point. Besides, GDDM-CM can obtain similar results as monte-carlo sampling method does and its calculation accuracy is better than that of the point estimate method. Moreover, the proposed GDDM-CM can greatly reduce the calculation time compared with the other two methods. Utilizing the GDDM-CM, the coupling effects of different individuals are investigated and the weak points in each individual can be identified.

Study of purchasing behavior evolution of work-safety-service based on hierarchical mixed supervision.

This paper explores the evolutionary rules of work-safety-service purchasing strategies of enterprises under hierarchical mixed supervision. Considering the influence of the central government's inspection on local governments, an evolutionary game model is built which depicts the mutual interactions of work-safety-service purchasing strategies from enterprises and supervision strategies from local governments. The existence and stability of system equilibrium points are analyzed, and the influence of different parameters' variation on the evolutionary results is demonstrated through numerical simulation. It is found that different ranges of parameters affect the number and stability of equilibrium points and the evolutionary trend. The system converges to two different patterns. In the first pattern, local governments choose to supervise enterprises strictly and enterprises choose to purchase work-safety service, which is a desired pattern. In the second pattern, local governments choose to supervise enterprises loosely and enterprises choose not to purchase work-safety service, which is an undesired pattern. When it has five equilibrium points, it is feasible to make the system converge to the desired pattern through modifying relative parameters, avoiding the undesired pattern. The system is more likely to converge to the desired pattern with the higher initial ratio of local governments opting for strict enterprise supervision; the system is more likely to converge to the desired pattern when the central government exerts a stricter inspection on local governments; the system is more likely to converge to the desired pattern when local governments exert stricter ex ante and ex post safety supervision on enterprises. The system is more likely to converge to the undesired pattern when the ex ante supervision costs of local governments get higher. Subsidies from local governments for the purchase of work-safety service barely affect the evolutionary trend of the system.

Nonequilibrium dynamics in a three-state opinion-formation model with stochastic extreme switches.

We investigate the nonequilibrium dynamics of a three-state kinetic exchange model of opinion formation, where switches between extreme states are possible, depending on the value of a parameter q. The mean field dynamical equationsare derived and analyzed for any q. The fate of the system under the evolutionary rules used in S. Biswas etal. [Physica A 391, 3257 (2012)0378-437110.1016/j.physa.2012.01.046] shows that it is dependent on the value of q and the initial state in general. For q=1, which allows the extreme switches maximally, a quasiconservation in the dynamics is obtained which renders it equivalent to the voter model. For general q values, a "frozen" disordered fixed point is obtained which acts as an attractor for all initially disordered states. For other initial states, the order parameter grows with time t as exp[α(q)t] where α=1-q/3-q for q≠1 and follows a power law behavior for q=1. Numerical simulations using a fully connected agent-based model provide additional results like the system size dependence of the exit probability and consensus times that further accentuate the different behavior of the model for q=1 and q≠1. The results are compared with the nonequilibrium phenomena in other well-known dynamical systems.