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Phononic crystals (PnCs) are a kind of synthetic composite materials with spatial periodicity. Owing to the unique properties, such as the band gaps (BGs), defect mode, wave localization, and wave beaming, PnCs have been applied in acoustic filters, vibration isolation, noise reduction, and sonar detection, attracting increasing attention in recent years. Among these useful properties, the filter characteristics of PnCs have consistently been a popular research topic. Notably, these existing works primarily focus on the multi-channel output of the same frequency, or the single-channel output of the different frequencies. Studies that investigate a multi-channel output with different frequencies, or specified frequencies, are rare. Most of a filter’s functionality is achieved through structures composed of local resonant PnCs, which usually require a more cumbersome design and more expensive costs. However, compared to local resonant PnCs, Bragg scattering PnCs are more commonly accepted in practical applications because of their simple design and easily available materials. Accordingly, this paper studies the multi-channel output of different frequencies by adopting Bragg scattering PnCs. The finite element methods (FEM) of the band structure and transmission spectrum are performed with COMSOL. The BG in the ΓX direction of the band diagram is used as the test target. Periodic plates with criss-crossed elliptical holes can provide wider BGs because of their symmetry breaking. Based on such finding, a two-channel waveguide structure consisting of three representative volume elements (RVE) of different sizes (A, B and C) is constructed, and the two-channel filtering performance is subsequently investigated by the finite element analysis. The research frequency range is set from 0 to 18 kHz. By comparing three RVE’s energy band structures, we can see that the frequency range of BG of A is almost between those of B and C, with relatively small overlap BG. Such BG characteristic can be utilized for the broadband filtering application. When the elastic wave propagates in the two-channel PnC structure consisting of three different sizes, there is supposed to be three situations. (1) When the frequency range of the input excitation is between 5.15 and 7.55 kHz, the elastic wave can pass through the up-channel consisting of A and B, but is forbidden to propagate through C due to the BG. (2) When the frequency range of the input excitation is between 7.55 and 15.16 kHz, the wave is not allowed to propagate neither through up or down-channel because of the BG of A. (3) When the frequency falls into the range between 15.16 and 18 kHz, then the down-channel formed by A and C is the only choice for the wave to pass through. According to the theoretical model, a two-channel PnC plate of acrylic material (PMMA) is fabricated to conduct the transmission experiments. The experimental data agree well with the numerical results, which indicate that the directional transmission of elastic waves within different frequency ranges in a two-channel structure can be achieved by adjusting the size of the three RVE. This paper could provide a novel approach for the application of PnCs in multi-channel filtering.

Sapping caused by prevailing wind erosion is one of the most significant factors in the deterioration of earthen sites located in Datong County, Qinghai Province, China. Long-term effects of wind may cause surface erosion, or even serious damage to the Great Wall of Ming Dynasty. Difference of sapping quantity should be attributed to variability of the prevailing wind directions. To better understand the effects of wind direction on erosion, meteorological data in the study area for fifty-two years (from 1961 to 2013) were collected and statistically analyzed. Sapping quantity of earthen structure was measured by field investigation on the Wall along the ridge whose azimuth ranges from 95°–244° and mainly concentrated in 140°–210°. Results showing obvious difference of sapping quantity could be observed at both sides of the Wall under the prevailing wind directions (ESE, SE and SSE). Further, the Wall was divided into small segments with a length of 20 m for comparison and maximum sapping quantity could be found at the Wall whose azimuth is at an angle of 30° to the prevailing wind. The aim of this study is to provide reference for the deterioration of the Wall under long-term wind pressure, and provide a targeted conservation method for earthen structure.

Ferroelectric thin film capacitors have attracted increasing attention because of their high energy storage density and fast charge-discharge speed, but less attention has been paid to the realization of flexible capacitors for wearable electronics and power systems. In this work, flexible xMn-BiMg0.5 Ti0.7 O3 (xMn-BMT0.7 ) thin film capacitors with ultrahigh energy storage density and good stability are deposited on mica substrate. The introduction of excess TiO2 with an amorphous structure contributes to the forming of the polar nano regions, resulting in the reduced ferroelectric hysteresis. In order to further improve the energy storage performance, Mn doping increases the polarization by regulating chemical pressure in the lattices and inhibits the valence change of Ti4+ . Especially in the 1.5% Mn-BMT0.7 film capacitor, an ultrahigh energy storage density of 124 J cm-3 and an outstanding efficiency of 77% are obtained, which is one of the best energy storage performances recorded for ferroelectric capacitors. In addition, the flexible ferroelectric film capacitor also exhibits good thermal stability (25-200 °C), high frequency reliability (500 Hz-10 kHz), excellent electrical (108 cycles), and mechanical (104 cycles) fatigue properties. This work is expected to pave the way for the application of BMT-based thin film capacitors in flexible energy storage systems.

Landslides are usually triggered by strong earthquakes, heavy rainfalls, or intensive human activities in common wisdom. However, an unexpected landslide occurred in the Yabakei area, Nakatsu, Oita, Japan, at the pre-dawn hour 3:50 a.m. on 11 April 2018, without any accompanying rainfall and earthquake records during the event. This catastrophic landslide was 200 m in width, 110 m in height, and 60,000 m3 in mass volume, damaging four residential buildings with fatalities of six residents at the landslide toe. Field investigation was conducted immediately to identify geological setting, hydrological condition, and landslide geomorphological characteristics. Key findings speculate that infiltration of groundwater stored in the internal fractures led to the swelling and breaking of illite and askanite in the weathered sediment rocks, resulting in the failure of the Yabakei landslide. To reproduce and explore the dynamic process of this landslide event, based on spatial GIS data, we applied the proposed three-dimensional, Herschel-Bulkley-Papanastasiou rheology model-based smooth particle hydrodynamics (HBP-SPH) method to simulate the landslide dynamic process. Buildings in the landslide area are covered by a set of surfaced cells (SC) to analyze the mass impact on the residential buildings. Results showed good accordance between observation and simulation by the proposed SC-HBP-SPH method. The landslide impact force to the residential buildings could be up to 4224.89 kN, as indicated by the simulation.

Numerical simulation of the debris-flow process is commonly based on the shallow water equations. However, as a two-phase anisotropic mixture, debris flows display complex rheological behavior, making it difficult to model or to simulate these using standard approaches. In this paper, an improved cellular automaton (CA) model is developed for simulating the extent of debris-flow run-out. The CA model consists of three essential components: cellular space, lattice relation, and transition function. A two-dimensional rectangular cellular space is generated from mesh grid in the digital terrain model data, and the Moore neighborhood type is selected as the lattice relation. We also use a transition function based on a Monte Carlo iteration algorithm to automatically search the flow direction and flow routine. Specifically, this new transition function combines the topography function and persistence function (due to the flow inertia), and is advanced in its ability to avoid certain illogical lateral spreading due to abrupt changes in topography. In addition, in contrast to previous studies, in the present work, we regressed the persistence function from a well-documented flume experiment, rather than using a manipulated constant value as described in earlier empirical studies. Our results show that the debris-flow persistence function is closely related to the channel slope. It approximates the law of cosines at a steep slope and Gamma law at a gentle slope. To illustrate the performance of the improved CA model, we selected the 2010 Yohutagawa debris-flow event in Japan as a case study. Our results show that the simulated deposition perimeter pattern and run-out distance are in high accordance with the data from in situ investigation.

To study the adaptability of cement-improved expansive soil as a heavy-haul railway subgrade filling material, based on a test section of the Inner Mongolia-Jiangxi railway cement-improved expansive soil embankment, cyclic vibration tests were conducted under different axle load, train speed and service environment conditions. By analysing dynamic parameters such as dynamic stress, acceleration and dynamic displacement at different subgrade positions, the train dynamic load distribution and attenuation law in the cement-improved subgrade were obtained, and the axle load, train speed and rainfall effects on the dynamic cement-improved subgrade response were analysed. The dynamic parameters are linearly attenuated along the subgrade depth and lateral direction in the same filling structure layer. The dynamic stress attenuation at the bottom of the subgrade surface layer is approximately 49%, and that at the bottom of the lowermost subgrade layer is 76%. The attenuation of the coarse-grained filler is larger than that of the cement-improved expansive soil; the dynamic parameter values at various subgrade positions increase linearly with increasing train speed and axle load. The closer the vibration source is, the larger the dynamic parameter increment; the change in the subgrade water content has a certain effect on the subgrade’s dynamic response characteristics. In the immersed state, the subgrade dynamic parameter value is greater than the natural state value, and the subgrade accumulated deformation will be promoted after subgrade immersion in water.

In order to insure the stability of embankment and ground during construction, and to meet the requirement of residual settlement, the filling-rate of embankment should be strictly restrained by the Displacement Pile (DP) lateral displacement rate according to rule (Ye 1998) and research (Bai 1992). Thus a further investigation of the performance of DP in soft ground is necessary. Based on the orthogonal principle, four factors (i.e. loading rate, reinforcement mat and sand mat, loading plate size and its pattern, lateral restrain) were selected as affecting factors influencing the DP’s lateral displacement rate. Nine model tests designed by orthogonal -table L9 (43) were carried out to find that the affecting orders of four factors keep the same during the loading periods, and that the law of affecting degree of four factors along the depth, with increase of loading grade and regression equations between affecting degree and loading grades are obtained.

The asymmetrical distribution of debris-flow velocity in a cross-section has long been observed and is currently regarded as one of the most essential issues in debris-flow research. Due to a lack of quantitative models for the velocity distributions of debris flows, most studies consider only the mean velocity. However, to optimize countermeasure structures, to estimate the erosion rate, or to evaluate the constitutive equations for shear behavior, it is beneficial to know the velocity profile in a cross-section. In this paper, a generalized model of typical channel geometries (e.g., rectangular, trapezoid, or V-shape) is proposed. A description of the velocity distribution that optimizes the Manning–Strickler velocity equation for transverse distribution and Egashira’s velocity equation for vertical distribution is presented; thus, the debris-flow velocity at any point in the cross-section can be calculated and the distribution profile therefore obtained. A well-documented debris-flow reference case and the Jiasikou debris flow in the high-seismic-intensity zone of the Wenchuan earthquake are selected as case studies to demonstrate the model. Analyses of both cases confirm the asymmetrical distribution of debris-flow velocity in cross-section, as originally expected. This shows that the velocity at the top surface in the middle of the channel is much larger than that at each sidewall and than the mean value calculated by former equations. The obtained velocity distribution profile is a better approximation of the observed field profiles.

Due to the symmetry breaking on surfaces of a ferroelectric crystal, the polarizations on surfaces are different from those inside the crystal. To describe this surface polarization effect which depends on the surface atomic termination, the extrapolation length is incorporated in the phase-field method based on the time-dependent Ginzburg-Landau equation to investigate different surface polarizations and their influence on the electrocaloric properties in PbTiO3 nanocylinders. The simulation results show that the extrapolation length can alter the maximum value of the adiabatic temperature change and shift its temperature location.

The mechanical behavior of natural clays is affected by their inherent anisotropy and metastable soil structure. A simple hierarchical model that considers initial anisotropy and destructuration was formulated within the framework of critical state soil mechanics. In the proposed model, stress sensitivity and a destructuration index were introduced to account for the degree of bonding and the rate of destructuration, respectively. An inclined yield surface was used to incorporate the effect of the initial anisotropy. The proposed model can be degenerated to the Modified Cam Clay model by setting the initial stress sensitivity equal to unity and using a horizontal yield surface. Reasonable agreement between the model simulations and the experimental results on a variety of stress paths demonstrated that the proposed model can capture well the deformation behavior of natural clay and reconstituted soil. The model was implemented into the finite element program for the numerical analysis of an embankment on soft clay improved with prefabricated vertical drains. The numerical predictions were compared with the field-measured data in terms of embankment settlement. Additionally, the numerical simulations were analyzed in terms of horizontal displacements, excess pore water pressure, mean effective stress and volumetric strain. All of the simulations and comparisons indicate the importance of considering the effects of plastic anisotropy, interparticle bonding and destructuration caused by loading beyond yield stress and field disturbance in analyzing the behavior of an embankment on natural soft clay.

The FLO-2D model has long been validated as an efficient tool to simulate the motion behavior of debris flow, but could not consider bed-sediment entrainment in the simulation. Bed sediment entrainment is an important feature of debris flow and sometimes amplifies the debris flow magnitude manifold. In this paper, we present a simple preliminary approach to evaluate the potential entrainment and incorporate it into the FLO-2D model. In the presented approach, the bed sediment entrainment is simplified as the process that bed shear stress of the flow is sufficiently high to overcome the basal resistance of the bed and incorporate this part of the bed into the flow. In this way, we obtain a solution to calculate the potential entrainment depth of bed sediment by debris flow. To estimate the total entrainment volume along the path, as well as the variation of hydraulic condition of post-entrainment debris flow, we divide the path into finite segments, calculate the entrainment volume of each segment, and obtain the variation of hydraulic condition by a discrete algorithm. In order to demonstrate this approach, a debris flow event occurred at Yohutagawa region, Japan, 2010, is selected as a case study. We calculate the post-entrainment volume and hydraulic condition of debris flow of this case. Furthermore, we also reproduce this event by the FLO-2D model. Results show that both the calculated total erosion volume and simulated deposition results are in good agreement with the field investigation.

Mud depth of debris flow is an essential parameter for assessing the hazard magnitude in an event. However, direct prediction of mud depth in a natural river channel is a scientific challenge because current methods often treat the complex relief of bed surface as a rectangular one, which makes the prediction illogical. In this paper, we propose a new theoretical approach, the so-called numerical integral method-based approach for estimating the maximum mud depth of debris flow at a complex cross-section in a natural river channel. Given a predefined peak discharge of the debris-flow event, the numerical integral method-based iteration algorithm uses the Riemann method to search for an approximate mud depth. In contrast to the previous methods, the presented approach addresses an important issue, namely it takes into account the complex shape of the bed surface and superelevation at the bend for natural channels. Two cases are used to illustrate the performance and advantages of the presented approach: one is a well-documented event in the previous study, and the other is a debris-flow event after Ms. 8.0 Wenchuan earthquake. An engineering application regarding the rational design of a debris-flow canal is subsequently discussed. The canal was completely destroyed in a debris flow event in 2008. We used the proposed method to back-analyze the mud depth and velocity in the canal. It was found that the abrupt decrease of mud depth from the natural channel to the concrete canal significantly reduced the transportation capability, thereby causing blockage in the canal. The canal was modified and reconstructed in 2009 with suggested improvements from the proposed method, and successfully transported subsequent debris flow in 2011.

Typical characteristics of remote sensing applications are concurrent tasks, such as those found in disaster rapid response. The existing composition approach to geographical information processing service chain, searches for an optimisation solution and is what can be deemed a ''selfish'' way. This way leads to problems of conflict amongst concurrent tasks and decreases the performance of all service chains. In this study, a non-cooperative game-based mathematical model to analyse the competitive relationships between tasks, is proposed. A best response function is used, to assure each task maintains utility optimisation by considering composition strategies of other tasks and quantifying conflicts between tasks. Based on this, an iterative algorithm that converges to Nash equilibrium is presented, the aim being to provide good convergence and maximise the utilisation of all tasks under concurrent task conditions. Theoretical analyses and experiments showed that the newly proposed method, when compared to existing service composition methods, has better practical utility in all tasks.

The unbalanced age structure aspect of China's basic medical insurance system increases payment risk and hampers sustainable and healthy development. Combining the actuarial approaches of life insurance and non-life insurance, the principle of long-term fund balance is applied to establish a model with which to calculate the vertically balanced rate of the basic medical insurance system. Analysis of data from City S indicates that the vertically balanced rate is significantly higher than the current premium rate. The vertically balanced rate increases when an older age is used for starting premium payments; the vertically balanced rate is higher for females than for males. As the investment return rate increases, the vertically balanced rate decreases. The vertically balanced rate can be used to adjust the whole-life premium rate, the minimum premium period, the minimum age of participating in the system, continuing and supplemental premiums, and benefit adjustments. It can also provide a scientific basis...

To use many asbestos tailings collected in Ya-Lu highway, and to explore the feasibility of using asbestos tailings as aggregates in common asphalt mixtures, and properties of some asphalt mixtures were evaluated as well. X-ray diffraction (XRD), X-ray fluorescent (XRF), and atomic absorption spectrophotometry (AAS) were employed to determine the solid waste content of copper, zinc, lead, and cadmium. Volume properties and pavement performances of AC-25 asphalt mixture with asbestos tailings were also evaluated compared with those with basalt as aggregates. XRD and XRF measurement results infer that asbestos tailing is an excellent road material. Volume properties of AC-25 asphalt mixture with asbestos tailings satisfied the related specifications. No heavy metals and toxic pollution were detected in AAS test and the value of pH test is 8.23, which is help to the adhesion with asphalt in the asphalt concrete. When compared with basalt, high temperature property and the resistance to low temperature cracking of AC-25 asphalt mixture was improved by using asbestos tailings as aggregates. In-service AC-25 asphalt pavement with asbestos tailings also presented excellent performance and British Pendulum Number (BPN) coefficient of surface.

FaTing mountain landslide, which locates in Xue town, Li county of Sichuan Province, is a seismic secondary geological hazard triggered by Wenchuan earthquake of May.12.2008. The tremendous earthquake caused the trailing edge of the FaTing mountain slide cracking and the soil of slide surface a large deformation. This earthquake-induced landslide was also triggered by the heavy rainfall, and it had been recognized as a serious threat to the houses and roads below the slope before it was prevented and mitigated. In this paper, based on the field investigation, an exhaustively comparison of the basic characteristics of landslide before and after earthquake is proposed, thus the coupling progress between endogenetic and exogenetic geological processes is analyzed, and the landslide triggering factors by earthquake are analyzed, too. According to studies above, stability calculation before and after the earthquake is conducted and the landslide countermeasures is proposed, including crack sealing, interception drain, loose mass removal and retaining wall. This study is also supposed to serve as a consult for related landslide mitigation and monitoring work.

Optimal analysis in the mitigation of debris flow hazard was generally conducted with expert judgments or by simply scheme option, which would get inadequate and uneconomic decision sometimes. Set of feasible scheme in the mitigation of debris flow hazard along expressway was proposed with constraints according to the mathematical programming methods. The full set of mitigation modes was served as initial condition, which help to reduce the inadequate of decision. The order of priority of each kind of mitigation mode was suggested, as well as the analysis procedure in the proposing of feasible schemes, which proposed a theoretical rule, not empirical, to guide the analysis of mitigation scheme. Gradual constraint method was employed to assign the influencing factors of decision-making to constraint analysis in each grade, which resulted in a reduced amount of factors to be considered in each grade and help to enhance the analysis efficiency and reduce the difficulty at the meantime.