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[Objective] Based on the United Nations 2030 Sustainable Development Goals (SDGs), this study aimed to assess the resilience of the social-ecological system and explore the strategies to enhance the resilience of the social-ecosystem system in energy-rich areas, in order to promote sustainable transformation and high-quality development in these areas. [Methods] This study constructed a social-ecological system resilience assessment matrix applicable to energy-rich areas based on the resilience theory, and examined the change of social-ecological system resilience and optimization and enhancement strategies in the Shanxi-Shaanxi-Inner Mongolia energy-rich area from 2005 to 2020. [Results] The results show that: (1) From 2005 to 2020, the overall resilience of the social-ecological system in Shanxi-Shaanxi-Inner Mongolia energy-rich area showed an upward trend. The resilience of the socioeconomic system showed a trend of decreasing first then rising, the resilience of the natural resources system showed a trend of increasing then decreasing, while the resilience of the ecological environment showed an increasing trend year by year. (2) The resilience of the social-ecological system exhibited phased characteristics under the influence of subsystem resilience in the study area. In the preparation and recovery stage, the improvement of social-ecological system resilience mainly benefited from the improvement of the ecological environment; In the coping and adaptation stage, the contribution of socioeconomic development to the resilience of regional social-ecological system was prominent. (3) The resilience pattern of the social-ecological system in the Shanxi-Shaanxi-Inner Mongolia energy-rich area has undergone significant changes, with a significant increase in cities with higher resilience. The socioeconomic resilience showed a pattern of high in the northwest and low in the southeast. The resilience of natural resources exhibited spatial characteristics of low in the northwest and high in the southeast. The ecological environment resilience showed a spatial pattern of high in the north and low in the south. (4) The lack of natural resources subsystem resilience was the key factor that restricted the improvement of resilience of the social-ecological system in the study area. [Conclusion] It is necessary to establish a collaborative governance mechanism of “stages + factors + systems + areas” in line with the United Nations 2030 Sustainable Development Goals (SDGs), aiming to continuously improve the resilience of the social-ecological system in the energy-rich area through various paths, such as accelerating the transformation and upgrading of resource-based economy, improving the efficiency of energy and resource utilization, improving the livelihood support system, and promoting ecological environment protection and restoration.

This study presented the investigation on the microstructure characteristics and the interaction among asphalt, crumb rubber (CR) and modifiers (softener, activator, and cross-linking agent) of crumb rubber compound modified asphalt (CRCMA) at process phases by microscopic testing techniques. The results showed that CRCMA had excellent rheological properties at high or low-temperature. The softener was only physically mixed with asphalt and did not change the microscopic morphology of the asphalt. The activator can break some of the chemical bonds of CR and promote the desulphurization degradation reaction which makes the asphalt show a large number of small-body type mesh structures and a small amount of chains in microscopic morphology. The crosslinking agent provided a source of sulphur to induce the crosslinking reaction which resulted in an increase in the reticulation of CRCMA. Finally, a modification mechanism model and the evolution mechanisms based on the microstructure characteristics at preparation phases of CRCMA were proposed. [ABSTRACT FROM AUTHOR]

In the present work, we consider the numerical approximation of the weak solutions of first-order system of evolution laws supplemented with entropy inequalities. The systems under consideration are hyperbolic as soon as a conservation form is satisfied, but such stability property may be lost for non-conservative systems. Here, we show that the robustness and the entropy stability of any finite volume numerical scheme can be restored by introducing a suitable artificial numerical viscosity. [ABSTRACT FROM AUTHOR]

This article presents an overview of an alternative approach to the systematization and evolution of biological organisms on the basis of the fractal-cluster theory. It presents the foundations of the fractal-cluster theory for the self-organizing systems of the organism class. Static and dynamic efficiency criteria based on the fractal-cluster relations and the analytical apparatus of nonequilibrium thermodynamics are presented. We introduce a highly sensitive static criterion, D, which determines the deviation in the value of the clusters and subclusters of the fractal-cluster system structures from their reference values. Other static criteria are the fractal-cluster entropy H and the free energy F of an organism. The dynamic criterion is based on Prigogine's theorem and is determined by the second differential of the temporal trend of the fractal-cluster entropy H. By using simulations of the cluster variations for biological organisms in the (H, D, F)-space, the criteria for the fractal-cluster stochastics as well as for energy and evolution laws are obtained. The relationship between the traditional and fractal-cluster approaches for identifying an organism is discussed. [ABSTRACT FROM AUTHOR]

Taking the sandstone subjected to pH = 1 and 3 HCl solutions as the research object, a dynamic chemical damage model was established based on mineral dissolution theory and chemical kinetics principles. A mechanical damage model of sandstone was also established by continuous damage mechanics theory. Moreover, a coupled chemical and mechanical damage model was deduced through microstress analysis, and a damage constitutive model for acid-corroded sandstone was constructed based on the Weibull distribution and the D–P criterion. The results showed that the acid–rock reaction showed evident time dependence, and the reaction rate decreased with the prolongation of corrosion time. The chemical damage variables of corroded sandstone subjected to pH = 1 and 3 HCl solutions reached 0.34 and 0.12 after 180 days, respectively. The damages caused by chemical and mechanical actions are nonlinear with the generalized damage. The chemical action can slow down the deterioration rate of sandstone under load, which was more obvious as the immersion time extended and the pH values of the solution declined. The stress state could change the deterioration process of sandstone, and the damage rate declined as the confining pressure increased. Finally, the uniaxial and triaxial compression test results verified the theoretical model, and the two agreed well, which verified that the coupled damage model is reasonable and applicable. [ABSTRACT FROM AUTHOR]

The Jingjiang reach, located in the middle Yangtze River, downstream of the Three Gorges Reservoir (TGR), is a typical curved reach. After TGR impoundment, the evolution behaviors of the Jingjiang reach changed, mainly because one or more original factors, including geological conditions, existing projects, bending radius, upper reaches' regimes, and incoming water and sediment changed. In this paper, these influencing factors were investigated by using the measured data and the mathematical models that were proposed by the authors in a previous paper, and consequently, the evolution laws of the curved reach were analyzed. The results showed that the existing river nodes reduced the influence of the upstream river regime on the evolution of curve reaches and also slowed the speed of convex bank scouring and concave bank depositing. Constructed projects could reduce sediment transport intensity from the concave bank to the convex bank. The decrease in incoming sediment after TGR impoundment was beneficial to convex bank scouring. The increase in median water period duration was favorable for convex bank scouring and concave bank depositing. Both convex bank and concave bank were scoured when the incoming sediment concentration decreased sharply. The sediment concentration of suspended load would stabilize near the saturation point, and the riverbed would be scoured when there is sediment concentration under the saturation point, while the riverbed would be deposited when the sediment concentration reaches the saturation point. HIGHLIGHTS Systematic analysis of channel changes downstream of the Three Gorges Reservoir.; The mechanism of upstream water flow change is introduced to analyze the downstream channel change.; Considering the impact of human activities on the giant reservoir.; Targeted analysis of longer river sections.; The results obtained from the study are useful for the management of water resources.;

• The relationship between non-uniform deformation and residual stress was analyzed, and the fundamental equations of residual stress were established. • The concept of the "non-coordination coefficient" was introduced, revealing the physical mechanism behind residual stress caused by non-uniform deformation. • The appearance of residual stress is essentially to force the inconsistent deformation of various parts inside the object to maintain its integrity and continuity. • The difference in the severity of "penetrability" induced by different temperature gradients determines the difference in residual stress between rolled and quenched rings. • Under the same process conditions, 2219 Al-Cu alloy larger rings have higher and more non-uniform residual stress than smaller rings. The large-scale ring components, as thin-walled structures, are prone to unpredictable machining deformation due to the initial residual stresses introduced by rolling and quenching, which seriously affect the dimensional accuracy and service life of the ring components. Therefore, the relief and homogenization of residual stress inside large-scale ring components is crucial. However, the existing studies rarely involve the essential causes and the evolution laws of residual stresses during the manufacturing of ring components, which are indispensable for understanding the failure mechanisms of components caused by residual stresses and specifying relevant protective measures. Therefore, the evolution and distribution laws of stress-microstructure-property non-uniformity during the hot forming (ring rolling) and heat treatment (quenching) of 2219 Al-Cu alloy rings were precisely and deeply explored using scaled experiments in this paper. The relationship between non-uniform deformation and residual stresses was analyzed, and the basic equation that residual stresses must satisfy was established. Furthermore, the concept of the "non-coordination coefficient" was proposed, revealing the physical mechanism of residual stresses induced by non-uniform deformation. In addition, the influencing factors and formation mechanisms of residual stresses in the rolled and quenched state of rings were studied, and the essential reasons for the differences in residual stresses between the rolling and quenching processes were obtained. The experimental results indicate that the circumferential and axial residual stresses increased from 1.48 and 0.51 MPa to −142.68 and −122.31 MPa, respectively. The standard deviation changed from 13.47 and 33.52 MPa to 63.42 and 61.61 MPa, respectively. The maximum range of tensile strength, yield strength and elongation rates of the rolling and quenched state is 12.82 and 20.16 MPa, 17.49 and 22.14 MPa, and 8.62 % and 7.56 %, respectively. All fractures are microporous aggregation ductile, including dimple transgranular fracture and intergranular fracture. The quenched state exhibits a significantly larger grain size compared to the rolled state. The appearance of residual stress is essentially to force the inconsistent deformation of various parts inside the object to maintain its integrity and continuity, which leads to a local mismatch of micro-elements inside the ring and further induces non-uniform strain and stress. The difference in the severity of "penetrability" induced by different temperature gradients determines the difference in residual stress between rolled and quenched rings, larger rings have higher and more non-uniform residual stress than smaller rings under the same process conditions. The above results deepen the theoretical understanding of residual stress formation mechanisms and lay a theoretical foundation for the comprehensive evaluation of performance degradation and service failure analysis of large ring components. [ABSTRACT FROM AUTHOR]

This article presents an overview of an alternative approach to the systematization and evolution of biological organisms on the basis of the fractal-cluster theory. It presents the foundations of the fractal-cluster theory for the self-organizing systems of the organism class. Static and dynamic efficiency criteria based on the fractal-cluster relations and the analytical apparatus of nonequilibrium thermodynamics are presented. We introduce a highly sensitive static criterion, D, which determines the deviation in the value of the clusters and subclusters of the fractal-cluster system structures from their reference values. Other static criteria are the fractal-cluster entropy H and the free energy F of an organism. The dynamic criterion is based on Prigogine’s theorem and is determined by the second differential of the temporal trend of the fractal-cluster entropy H. By using simulations of the cluster variations for biological organisms in the (H, D, F)-space, the criteria for the fractal-cluster stochastics as well as for energy and evolution laws are obtained. The relationship between the traditional and fractal-cluster approaches for identifying an organism is discussed.

Background: DI-SO (Double inputs and single output) helical gears are the key components of many propulsion systems and the phenomenon of nonlinear instability caused by multiple time-varying parameters and unsymmetrical input loads cannot be ignored. Methods: The nonlinear dynamic model of the DI-SO helical gear system was studied considering multiple nonlinear factors, and the evolution laws of the dynamic characteristics with load and structural parameters were discovered by numerical analysis methods. Results: Abundant dynamic behaviors of periodic, quasi-periodic, harmonic, sub-harmonic, multi-harmonic, and chaotic responses are revealed with the variation of the system parameters. The increases of the load parameters, such as the excitation frequency, the load ratio, and the load value, are beneficial to improve the stability of the system. With the increasing structural parameters of the helix angle and the face width, the dynamic response of the system changes in fluctuation. Conclusion: This study puts forward the importance of appropriate rotate speed, heavy load, and high contact ratio for the stability of the system and provides a theoretical reference for the design and optimization of the propulsion system with DI-SO helical gears. [ABSTRACT FROM AUTHOR]

This article proposes a consistent and general approach to train physics-augmented neural networks with observable data to enrich and represent nonlinear history-dependent material behaviors in terms of both state equations and evolution laws. In this learning strategy consistent with thermodynamics, the constitutive model is expressed using two potentials (free energy and dissipation potential) which are represented by input-convex neural networks, thus automatically satisfying the principles of thermodynamics. The neural network is trained thanks to an unsupervised procedure that does not rely on strain–stress pairs but needs only partial strain or displacement measurements inside the structure, moreover with uncertain boundary conditions. This method is based on the minimization of the modified Constitutive Relation Error functional, and it extends previous works on this error measure for neural networks to the case of history-dependent behaviors, which requires to design a specific minimization procedure. Given that neural networks for typical structural health monitoring applications often need to be trained online, there is here a significant emphasis placed on automatically and adaptively tuning crucial hyperparameters such as learning rate or weighting between losses. The method is evaluated on elastoplastic and elastoviscoplastic test cases with synthetic data collected from optic fiber or full-field measurements. It is shown that the method can properly learn hidden behaviors, achieves high robustness to noise level, and low sensitivity to user-defined hyperparameters. • A consistent hybrid approach is proposed to learn complex history-dependent constitutive laws. • The unsupervised learning integrates a performance criterion related to modeling error. • An automatic adaptive tuning of hyper-parameters is derived within this strategy. • A specific algorithm is introduced to tackle admissibility constraints and nonlinearities. • The interest and robustness of the approach are validated on several nonlinear constitutive laws. [ABSTRACT FROM AUTHOR]

To protect groundwater and urban ecological environment, much more sponge cities have been built in China. The sponge road is an important part of a sponge city. In recent years, Shijiazhuang Municipal Design Institute proposes a new sponge road structure, namely planting soil and crushed stone green belt, and it has been extensively used in Shijiazhuang City. In the design of the road structure, it is a key issue whether the infiltration rainwater quality pollutes the groundwater. Therefore, it is necessary to investigate the pollution of road rainwater runoff in Shijiazhuang City for the design of sponge road and the construction of sponge city. To obtain the characteristics of rainwater runoff pollution in Shijiazhuang City, four investigation points are chosen at the intersection of the Nanerhuan Road and Yuxiang Street, the east gate of Hebei University of Science and Technology, the site under the Xierhuan Road and Zhongshan Road overpass, and the catch-basin along the roadside in Shijiazhuang City. The investigating points are located in the main road of Shijiazhuang urban area, which covers Shijiazhuang City, and can represent the pollution characteristics of road runoff in Shijiazhuang City. Six rainfalls are collected from March to June in 2017. The rainfall on 3, May is viewed as typical middle and light one which is studied in this paper. The concentration of COD, TP, TN, NH3-N and SS in road runoff is tested by potassium dichromate method, ammonium molybdate spectrophotometry, potassium persulfate digestion-UV spectrophotometry and Nessler’s reagent spectrophotometry and filter paper filtration, respectively. The concentrations of Zn ions and Pb ions are tested by inductively coupled plasma method. According to the test results, the concentration evolutions of COD, TP, TN, NH3-N, SS, Zn and Pb ion in runoff during rainfall are studied. The results show that the contaminant concentration approximately decreases during the rainfall, and then maintain stable for 90 min. The relation between contaminant concentration and rainfall time follows the form of negative exponential function. Based on the investigation results, the design values of pollutant concentrations at the initial runoff and the long runoff of rainwater in Shijiazhuang are proposed by time-weighted average method and rainfall-weighted average method, respectively. The recommended values by former method for initial runoff in Shijiazhuang are as follows: TN, NH3-N, TP, SS and COD are 14.49 mg/L, 10.93 mg/L, 0.45 mg/L, 651.00 mg/L and 437.73 mg/L. The recommended values by former method for long runoff of water in Shijiazhuang are as follows: in 90 min TN, NH3-N, TP, SS and COD are 8.05 mg/L, 5.60 mg/L, 0.59 mg/L, 559.22 mg/L, and 237.96 mg/L, respectively. After 90 min they are 5.13 mg/L, 4.11 mg/L, 0.58 mg/L, 422.67 mg/L and 97.35 mg/L. The recommended values by later method for initial runoff in Shijiazhuang are as follows: TN, NH3-N, TP, SS and COD are 14.40 mg/L, 10.86 mg/L, 0.50 mg/L, 684.10 mg/L and 440.08 mg/L. The recommended values by later method for long runoff of water in Shijiazhuang are as follows: in 90 min TN, NH3-N, TP, SS and COD are 12.46 mg/L, 9.19 mg/L, 0. 52 mg/L, 642.80 mg/L and 363.92 mg/L. After 90 min they are 5.13 mg/L, 4.11 mg/L, 0.58 mg/L, 423.30 mg/L and 97.35 mg/L. Overall the proposed concentration values by the rainfall weighted average method are slightly larger than those by the time weighted average method. For hardly degradable Zn and Pb ions in the soil, the 30 min time-weighted concentration at the initial runoff and the long runoff of rainwater is proposed as the design values of runoff rainwater. The recommended design values of Zn and Pb ions are 0.67 mg/L and 0.11 mg/L, respectively.

This paper was to explore distribution and evolution of surrounding rock stress as well as roadway deformation failure during the exploitation of working faces in complex stope. Here, distribution and evolution laws of surrounding rock stress and strata pressure behaviors in the complex island panels 1213(1) in a mine in Huainan Mine during early isolation, overhead mining, normal isolation and stopping in gob were analyzed by combining FLAC3D numerical simulation and field measurement. Results were shown that surrounding rock stress distribution along the strike direction and incline direction, abutment pressure peak value and position as well as surrounding rock deformation in the roadway were different in different mining stages. Different spatial stope layout (left and right gob, lower gob and upper gob) could influence the abutment pressure distribution on working faces, stress concentration range and surrounding rock deformation in roadway significantly. Therefore, professional analysis, reasonable design and safety mining should be performed in advance according to specific engineering geological conditions. Research conclusions could provide certain engineering references and guidance to stope arrangement, optimal design of mining roadway and mine pressure control. [ABSTRACT FROM AUTHOR]

Blast ground vibration is the integrated result of body waves and surface waves. However, the contribution of various waves and their evolution laws have not been well studied, and the concept of the influence areas of various waves is rarely mentioned in current studies. In this paper, using the polarization analysis approach, the seismic components and the evolution of various waves induced by a vertical blasthole are analyzed in two case studies. Then, based on the test results, the partition of the influence areas of various waves is discussed. The results indicate that the proportion of different seismic components is not a constant, but rather, the dominant wave may change to another type with r (where r is the distance to the blasthole axis), and the dominant motion directions of various waves are distinct. For a vertical blasthole, the P-wave is a significant component in both near and far fields, and becomes the dominant wave beyond r = 2.3 h (where h is the buried depth of the explosive), furthermore its particle motion gradually rotates to the horizontal direction with r increases. The S-wave only dominates within r = 2.3 h, but its effect can be ignored when the R-wave is well developed. The R-wave is not suddenly created but gradually grows to an identifiable feature at r = 5 h, and it dominates the vertical vibration if r exceeds (43 ~ 45)h (59 ~ 62 m/kg1/2). Thus, the P-wave is a non-negligible threat to ground structures in vertical-hole blasting. Nevertheless, the P-wave component is commonly ignored in earthquakes, where the S- and R-waves are considered troublesome. The evolution of seismic components induced by blasting has some differences from the expectations in earthquakes. [ABSTRACT FROM AUTHOR]

Undesirable machining damages exist frequently in the conventional machining processes of CFRP, causing significant decline in the performance of CFRP components. For effectively suppressing various machining damages, this study aims to reveal the evolution laws of the fiber-matrix interface crack, which can be regarded as the origin of majority of the machining damages. In order to accurately and conveniently obtain the evolution laws determined by numerous coupled factors, the study is conducted through a combined method of experiments and machine-learning predictions. Specifically, orthogonal cutting experiments are conducted for analyzing the fiber-matrix interface crack's types and depth, and upon these characteristics predictive models based on machine learning are established for acquiring sufficient data so that reliable evolution laws can be obtained. From the results, it is found that there are four evolution types in all and when "burrs and cracks" exist, the crack depth increases obviously, and both the evolution types and depth are mainly determined by the fiber cutting angle. According to this, preliminary optimization methods of machining CFRP are proposed. The conclusions of this study are beneficial to facilitate the development of high-quality and high-efficiency machining technologies of CFRP. [ABSTRACT FROM AUTHOR]

In order to study evolution laws of tensile fractures in a coal mining area, based on the classification of the fractures formed by mining, a physical simulation test was carried out to simulate the dynamic evolution process of tensile fractures in coal mining areas. The results showed that after the coal in the mining area was mined, the mining area underwent obvious movement and deformation and forms tensile fractures. As the mining working face was advanced, the tensile fractures underwent the dynamic process of generation, development and closure. The changing curves of density of tensile fractures with the increase of mining length of the working face liked a ladder (it increased slowly and then rapidly) and then had two peaks (the second peak was higher than the first peak). [ABSTRACT FROM AUTHOR]

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The crack property of expansive soil is one of the important characteristics, which is different from other types of soils. The development of cracks greatly affects the engineering properties of expansive soils. In order to study the meso-structural characteristic of cracked expansive soil, the dry-wet cycle test, triaxial soaking test and isotropic loading test were carried out on the remolded expansive soil in scientific research station of Logistics Engineering University in Hanzhong city, Shanxi province, China. The data including volumetric strain and deviatoric strain were obtained by these tests. Using CT (computerized tomography), test samples were scanned nondestructively in real-time to obtain CT images. The whole evolving process of cracks in expansive soils was investigated under the action of water and external force from the microscopic view. The effect of the crack on the macro-meso deformation behavior of expansive soil was studied by the relationship between the micro data and macro physical parameters. Test results showed that, under unconstrained conditions of dry-wet cycles, the edges and the gathering holes area of expansive soil sample were easy to form crack. Volume shrinkage caused by dry-wet cycle of expansive soil had a stable asymptote line and would tend to a stable value. The volume change of the expansive soil had experienced 3 stages in triaxial soaking test with the water and external force. Firstly, in the initial stage of triaxial soaking test, expansive force caused by soaking water led to wetting expansive deformation of cracked expansive soil. Secondly, the softening effect appeared and the expansion force gradually decreased with the increase of water content, under the influence of confining pressure and deviatoric stress, the shearing shrinkage was followed. Thirdly, in the late period of soaking test, the shear failure of the specimen under the effect of deviatoric stress caused the phenomenon of slight dilation. Cracked expansive soil during isotropic loading process had obvious yield phenomenon, taking yield point as the cut-off point, the curve of scanning data and pore ratio with the load increases was divided into rapid and slow volume shrink period. The rapid volume shrinkable period was related to cracks and holes closure, and the slow volume shrinkable period was related to the formation of the new structure which had ability to resist the external load. From the CT-scanning images of triaxial soaking test and isotropic loading test, under the action of water and external load, the irregular cracks and holes were gradually evolved into a regular circular hole, and the circular hole tended to close. With only the action of the external force, the crack was more difficult to complete closure. The interaction of water and external force made the expansive soil crack closure effect better than that of only external loading. Therefore, water plays a key role in the effect of the crack' development of expansive soil. The results would provide valuble information for the further understanding of the influence of cracks on the mechanical properties of expansive soil. [ABSTRACT FROM AUTHOR]

A new method for calculating the parameters of the hypoid pitch cone, which simplifies the calculation process, is proposed. The method can easily obtain the evolution laws of hypoid pitch cones. The evolution limits of the hypoid pitch cone can be obtained by calculation. The pinion pitch cone evolves from cylinder to cone, and the gear pitch cone evolves from plane to cylinder. In the evolution process, all pitch cones can meet the preset values of key parameters. The variation law of the values representing lubrication and contact characteristics on the whole tooth surface during the evolution of pitch cone is studied. • A single equation containing relationships determines the tangent cones is found. • The feasible region of the hypoid gear pitch cone is found. • The evolution process of the pitch cone is studied in the feasible region. • The characteristics evolution laws on the tooth surface are found. [ABSTRACT FROM AUTHOR]

In this study, a visualizable experimental platform of steam ejector oriented towards MED-TVC desalination system is constructed, and the evolution laws of two-phase choking flow and ejector's entrainment performance under various operating parameters are obtained. Further, a matching double-choking theory with consideration of the condensing flow is developed to explain the inherent reason behind these evolution laws. Key results revealed that the formed two-phase choking flows have great effects on ejector's entrainment performance. The primary jet flow choking area linearly increases as the primary steam pressure raises, and the entrainment choking area experiences a small reduction, while the extended flow area marginally increases. Accordingly, the entrainment ratio significantly decreases, while the choking cross-section is slightly shifted upstream. In addition, the primary jet flow choking area considerably decreases with increasing entrainment pressure, but the entrainment choking area is nearly unchanged and the extended flow area increases by more than 8 times. As a result, the entrainment ratio remarkably increases, the choking cross-section migration distances are much larger than that in the case of primary steam pressure varies. A meaningful guide evolves from fact that priority should be given to restrain the condensing flow for achieving a higher energy efficiency of ejector. • Two-phase choking flow regimes inside the steam ejector are visualized and analyzed. • Evolution laws of ejector's choking flow and entrainment performance are obtained. • An improved double-choking theory is developed to explain these evolution laws. • Essential relation between choking flow and entrainment performance is established. • Adverse effects of the two-phase choking flow on ejector performance are discussed. [ABSTRACT FROM AUTHOR]

The purpose of the paper is to identify the chemical characteristics of drinking groundwater and its distribution patterns in Pengyang County and to discover the hydrochemical evolution laws of groundwater. The temporal and spatial variation of groundwater hydrochemical characteristics and evolution laws were comprehensively and systematically studied based on the understanding of the geological, hydrogeological, meteorological and hydrological conditions. Many analytical methods such as descriptive statistics, geostatistical analysis, ionic ratio coefficient method and correlation analysis were adopted based on the underground water quality analysis data. Study results showed that variation coefficients of chemical parameters of pore water in unconsolidated rocks were relatively high which indicated that water chemical compositions are vulnerable to topography, meteorology, hydrology and human activities. TDS variation was in accordance with the changes in Ca2+, Mg2+ and SO42- concentration. Hydrochemical type varied from HCO3·SO4-Na·Ca·Mg type and HCO3·SO4-Ca·Mg type at the upper reaches towards gradually to HCO3-Na type at the lower reaches. Ionic ratio coefficient analysis showed that the hydrodynamic conditions of the pore water in loose rocks were better than that of pore-fissure water in clastic rocks and groundwater was non-marine deposited water. Its formation effects include the weathering leaching effects of the formation containing rock salt, water-rock interaction and cation exchange reaction. Hydrochemical characteristics were mainly controlled by geological and hydrogeological conditions. Correlation analysis showed that the dissolution of rock salt and sodium sulfate salt as well as calcite precipitation occurred in pore water and in pore-crack water in clastic rocks the dissolution of albite, K-feldspar and the precipitation of dolomite were also important effects. [ABSTRACT FROM AUTHOR]

The settlement of the right to defence represents the most powerful guarantee offered to a person investigated by the judiciary authorities that the respective person will not be subject to abuse within the investigation and the trial. Regardless of its modalities of expression - the assistance or the representation of the investigated person - the right to defence must be understood as the whole of legal means for invoking and finding the circumstances which support the defence as well as for applying the favourable legal dispositions. If nowadays the legal profession is regulated by a distinct law regarding its organization and exertion, things were very different once. During the mediaeval period, the defence of an investigated person was assigned to one of his relatives or to the husband (in case of a married woman). Subsequently, this duty was assigned to „vechilului judiciar“, to the lawyers with „cu ştiintă de pravilă“, and in Transylvania, to „procatorilor“ or „procuratorilor“. The modern age, strongly influenced by Western Europe, brought about the creation of an unprecedented legislative framework for the Romanian Countries, powerfully connected to the realities of those times. The result was that, at the same time with the adoption of a Criminal Procedure Code, of French and later Italian influence, real guarantees of the right to defence were conferred within the criminal trial. Eventually, under the strong influence of Soviet legislation, this underwent numerous limitations. Nowadays, due to the transposition into national law of international juridical instruments to which Romania is a part, the right to defence is acknowledged as an integral part of the human rights. [ABSTRACT FROM AUTHOR]

The aim of this paper is to develop a thermodynamically consistent micromechanical concept for the damage analysis of viscoelastic and quasi-brittle materials. As kinematical damage variables a set of scalar-, vector-, and tensor-valued functions is chosen to describe isotropic and anisotropic damage. Since the process of material degradation is governed by physical mechanisms on levels with different length scale, the macro- and mesolevel, where on the mesolevel microdefects evolve due to microforces, we formulate in this paper the dynamical balance laws for macro- and microforces and the first and second law of thermodynamics for macro- and mesolevel.Assuming a general form of the constitutive equations for thermo-viscoelastic and quasi-brittle materials, it is shown that according to the restrictions imposed by the Clausius–Duhem inequality macro- and microforces consist of two parts, a non-dissipative and a dissipative part, where on the mesolevel the latter can be regarded as driving forces on moving microdefects. It is shown that the non-dissipative forces can be derived from a free energy potential and the dissipative forces from a dissipation pseudo-potential, if its existence can be assured.The micromechanical damage theory presented in this paper can be considered as a framework which enables the formulation of various weakly nonlocal and gradient, respectively, damage models. This is outlined in detail for isotropic and anisotropic damage. [Copyright &y& Elsevier]

Recently, bionic thin-walled structures have attracted widespread attention in automotive safety design because of their excellent crashworthiness behavior and weight efficiency. In this paper, inspired by the evolution laws and microstructure of plant stems, a group of bionic tubes with m parts and n layers (PmLnBTs) are proposed and investigated by theoretical prediction and numerical analysis. Theoretical models of PmLnBTs are developed to predict the specific energy absorption. Finite element model is conducted with LS-DYNA and validated by a quasi-static axial crushing experiment. The accuracy of the theoretical model is verified by numerical analysis, and the maximum relative error is less than 7%. Furthermore, parametric studies are conducted to investigate the effects of geometric parameters on the energy absorption capability of PmLnBTs. The results indicate that the PmLnBTs exhibit superior crashworthiness performance compared to traditional bi-tubular circle tubes. Moreover, when designing such a bionic energy absorber, it can effectively improve the crashworthiness performance by appropriately increasing the number of layers, reducing the outermost circle diameter or avoiding innermost circle diameter value too large or too small. The findings of this paper provide a guidance for the design of energy absorber with excellent energy absorption performance. Image 1 • Inspired by the evolution laws and microstructure of plant steams, a group of bionic tubes namedPmLnBTs were proposed. • A theoretical model of PmLnBTs was established and validated to predict the energy absorption capability of PmLnBTs. • The PmLnBTs exhibit significant crashworthiness advantages than traditional bi-tubular circle tube (TBCT) with same mass. • The number of layers n and innermost circle diameter d have a significant effect on the crashworthiness of PmLnBTs. [ABSTRACT FROM AUTHOR]

• A double-choking theory is proposed. • A quantitative analysis of the entrainment choking flow has achieved. • The inherent reason behind the evolution law of ejector performance is illuminated. • The fundamental link between entrainment performance and choking flow is revealed. • The evolution laws under various operational and geometry parameters have explained. There are few systematic studies to investigate the inherent reason behind the evolution law of ejector performance, only some simple qualitative or roundabout analysis. In this paper, a double-choking theory is proposed to provide an in-depth explanation of the evolution laws of ejector performance. The systematic investigation and quantitative analysis focus on the influences of various operational and geometrical parameters on the ejector choking flows. Key results revealed that the flow area of the primary jet flow at the choking cross-section A py almost linearly increases with higher primary flow pressure p p0 , while the entrainment choking area A ey declines instead, and thus the entrainment ratio ε decreases. The mixing pressure p y significantly increases with entrainment pressure p e0 , and A py partly reduces. Consequently, A ey becomes larger and ε is accordingly with an over-double increase. A py undergoes a continuous decrease when the area ratio of primary nozzle λ t increases, and thus ε rises consistently although A ey1 eventually experiences a slight decrease. However, the choking state of the entrained flow would discontinue as λ t exceeds its critical value λ tc. Additionally, A ey increases substantially when the area ratio of the constant-area section λ 3 enlarges, while A py and p y always remain unchanged. Accordingly, ε follows the same increasing trajectory as A ey. These impactful results could serve as an essential guide for optimizing the ejector design, and also ensure a clearer perspective to understand the fundamental link between the ejector's entrainment performance and choking flow. [ABSTRACT FROM AUTHOR]