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As a promising new medical imaging method, photoacoustic imaging (PAI) has the advantages of optical resolution and acoustic depth of penetration. The transparent ultrasound transducer (TUT), as a novel device applied to PAI, can combine the laser and acoustic beam coaxially to improve the imaging quality. Transparent piezoelectric materials are the key to developing piezoelectric TUTs. However, due to the birefringence and light scattering caused by ferroelectric domains, it is very hard to prepare transparent piezoelectric materials with both high optical transmittance and excellent piezoelectricity. In this study, 2.5 mol% Sm-doped 0.72Pb(Mg 1/3 Nb 2/3) O 3 -0.28PbTiO 3 (PMN-PT) ceramic with a piezoelectric coefficient d 33 of 1460 pC N−1 and an optical transmission of 69 % at Near-Infrared (NIR) is successfully prepared, and its optical, microstructure, ferroelectric and dielectric properties are fully studied. Subsequently, a 3 mm-diameter photoacoustic coaxial probe is fabricated, involving a transparent ultrasound transducer based on the prepared ceramic. The TUT has a center frequency (f c) of 18.5 MHz, a −6 dB bandwidth of 20 %, and a high effective electromechanical factor ( k eff) of 0.62. In addition, the imaging capability of the miniature probe is firstly confirmed through photoacoustic/ultrasound dual-modality imaging of in-vivo animals and phantoms, which indicates that the proposed transparent piezoelectric ceramic has great potential for PA/US imaging. [Display omitted] • Transparent Sm-PMN-PT ceramic with high piezoelectric coeffcient (1460 pC N−1) is prepared. • A miniature transparent ultrasound transducer with a large electromechanical coupling factor k eff (0.62) is fabricated. • In-vivo photoacoustic-ultrasound imaging was performed by transparent piezoelectric ceramic firstly. [ABSTRACT FROM AUTHOR]

Human embryonic stem cells (hESCs) and their derived products offer great promise for targeted therapies and drug screening, however, the hESC differentiation process of mature neurons is a lengthy process. To accelerate the neuron production, an acoustic stimulator producing surface acoustic waves (SAWs) is proposed and realized by clamping a flexible printed circuit board (PCB) directly onto a piezoelectric substrate. Neural differentiation of the hESCs is greatly accelerated after application of the acoustic stimulations. Acceleration mechanisms for neural differentiation have been explored by bulk RNA sequencing, quantitative polymerase chain reaction (qPCR) and immunostaining. The RNA sequencing results show changes of extracellular matrix-related and physiological activity-related gene expression in the low or medium SAW dose group and the high SAW dose group, respectively. The neural progenitor cell markers, including Pax6, Sox1, Sox2, Sox10 and Nkx2-1 , are less expressed in the SAW dose groups compared with the control group by the qPCR. Other genes including Alk, Cenpf, Pcdh17 , and Actn3 are also found to be regulated by the acoustic stimulation. Moreover, the immunostaining confirmed that more mature neuron marker Tuj1 -positive cells, while less stem cell marker Sox2 -positive cells, are presented in the SAW dose groups. These results indicate that the SAW stimulation accelerated neural differentiation process. The acoustic stimulator fabricated by using the PCB is a promising tool in regulation of stem cell differentiation process applied in cell therapy. Human embryonic stem cells (hESC) are used for investigating the complex mechanisms involved in the development of specialized biological cells and organs. Different types of hESCs derived cell products can be used for cell therapy procedures aiming to regenerate functional tissues in patients who suffer from various degenerative diseases. Accelerating the hESCs' differentiation process can considerably benefit the clinical utilization of these cells. This study develops a highly effective acoustic stimulator working at ∼20 MHz to investigate what roles do acousto-mechanical stimuli play in the differentiation of hESCs. Our results show that acoustic dose alters the extracellular matrix and physiological activity-related gene expression, which indicates that the acoustic stimulation is an important tool for regulating the stem cells' differentiation processes in cell therapy. [Display omitted] [ABSTRACT FROM AUTHOR]

Haze scenes seriously degrade the performance of computer vision systems. Thus, the single image dehazing based on convolutional neural network (CNN), as an important direction of computer vision, has always attracted extraordinary attentions of researchers and made great progress on dehazing effects. However, there are still some non-trivial issues such as uneven dehazing and color distortion, which are not well addressed. To alleviate these issues, this work proposes a new multiscale feature fusion image dehazing network incorporating a contiguous memory mechanism (MFFDN-CM). Specifically, the pixel attention mechanism, continuous memory strategy and residual dense blocks are jointly integrated into the dehazing model with a prevalent encoder-decoder structure(U-Net). Firstly, our model obtains multiscale feature maps by subsampling operations, and further employs skip connections between the corresponding network layers to connect the feature maps between the encoder and the decoder for good feature fusion. Then, we introduce a continuous memory residual block to strengthen the information flows for feature reuse. Moreover, to leverage detail representation and accomplish adaptive dehazing according to the haze density, MFFDN-CM adopts a pixel attention module on the skip connections to combine the residual dense block module of the corresponding decoding layers. Finally, multiple residual blocks are exploited on the bottleneck in encoder-decoder structure to prevent network performance degradation due to vanishing gradients. Experimental results demonstrate the proposed model can achieve better dehazing performance than the state-of-the-art methods based on other deep neural networks. [ABSTRACT FROM AUTHOR]

Annular flow with liquid entrainment occurs in a wide variety of two-phase flow system. A novel control volume finite element method with adaptive unstructured meshes is employed here to study three-dimensional droplet deposition process in annular two-phase flow. The numerical framework consists of a ‘volume of fluid’ type method for the interface capturing and a force-balanced continuum surface force model for the surface tension on adaptive unstructured meshes. The numerical framework is validated against experimental measurements of a droplet impact problem and is then used to study the droplet deposition onto a flowing liquid film at atmospheric and high pressure conditions. Detailed complex interfacial structures during droplet impact are captured during the simulation, which agree with the experimental observations, demonstrating the capability of the present method. It is found that the effect of the ambient pressure on the fluid properties and interfacial tension plays an important role in the droplet deposition process and the associated interfacial phenomena. [ABSTRACT FROM AUTHOR]

Progress on the development of a general framework for the simulation of turbulent, compressible, multi-phase, multi-material flows is described. It is based on interface-capturing and a compositional approach in which each component represents a different phase/fluid. It uses fully-unstructured meshes so that the latest mesh adaptivity methods can be exploited. A control volume-finite element mixed formulation is used to discretise the equations spatially. This employs finite-element pairs in which the velocity has a linear discontinuous variation and the pressure has a quadratic continuous variation. Interface-capturing is performed using a novel high-order accurate compressive advection method. Two-level time stepping is used for efficient time-integration, and a Petrov–Galerkin approach is used as an implicit large-eddy simulation model. Predictions of the numerical method are compared against experimental results for a five-material collapsing water column test case. Results from numerical simulations of two- and three-phase horizontal slug flows using this method are also reported and directions for future work are also outlined. [ABSTRACT FROM AUTHOR]

Multiphase flows are often found in industrial and practical engineering applications, including bubbles, droplets, liquid film and waves. An adaptive unstructured mesh modelling framework is employed here to study interfacial flow problems, which can modify and adapt anisotropic unstructured meshes to better represent the underlying physics of multiphase problems and reduce computational effort without sacrificing accuracy. The numerical framework consists of a mixed control volume and finite element formulation, a ‘volume of fluid’-type method for the interface capturing based on a compressive control volume advection method and second-order finite element methods. The framework also features a force-balanced algorithm for the surface tension implementation, minimising the spurious velocities often found in such flows. Numerical examples of the Rayleigh–Taylor instability and a rising bubble are presented to show the ability of this adaptive unstructured mesh modelling framework to capture complex interface geometries and also to increase the efficiency in multiphase flow simulations. [ABSTRACT FROM AUTHOR]

Abstract: Wind effects on breaking solitary waves are investigated in this study using a two-phase flow model. The model solves the Reynolds-averaged Navier–Stokes equations with the turbulence model simultaneously for the flows both in the air and water, with the air–water interface calculated by the volume of fluid method. First, the proposed model was validated with the computations of a breaking solitary wave run-up on a 1:19.85 sloping beach in the absence of wind, and fairly good agreement between the computational results and experimental measurements was obtained. Further, detailed information of the water surface profiles, velocity fields, vorticity, turbulent stress, maximum run-up, evolution of maximum wave height, energy dissipation, plunging jet and splash-up phenomena is presented and discussed for breaking solitary waves in the presence of wind. The inclusion of wind alters the air flow structure above water waves, increases the generation of vorticity and turbulent stress, and affects the solitary wave shoaling, breaking and run-up processes. Wind increases the water particle velocities and causes water waves to break earlier and seaward, which agrees with the previous experiment. [Copyright &y& Elsevier]

Abstract: A two-phase flow model, which solves the flow in the air and water simultaneously, has been employed to investigate both spilling and plunging breakers in the surf zone with a focus during wave breaking. The model is based on the Reynolds-averaged Navier–Stokes equations with the turbulence model. The governing equations are solved using the finite volume method, with the partial cell treatment being implemented in a staggered Cartesian grid to deal with complex geometries. The PISO algorithm is utilised for the pressure–velocity coupling and the air–water interface is modelled by the interface capturing method via a high-resolution volume of fluid scheme. Numerical results are compared with experimental measurements and other numerical studies in terms of water surface elevations, mean flow and turbulence intensity, in which satisfactory agreement is obtained. In addition, water surface profiles, velocity and vorticity fields during wave breaking are also presented and discussed. It is shown that the present model is capable of simulating the wave overturning, air entrainment and splash-up processes. [Copyright &y& Elsevier]

Abstract: A large-eddy simulation study has been undertaken to investigate the turbulent structure of open-channel flow in an asymmetric compound channel. The dynamic sub-grid scale model has been employed in the model, with the partial cell treatment being implemented using a Cartesian grid structure to deal with the floodplain. The numerical model was used to predict the: primary velocity and secondary currents, boundary shear stress, turbulence intensities, turbulent kinetic energy, and Reynolds stresses. These parameters were compared with experimental measurements published in the literature, with relatively close agreement being obtained between both sets of results. Furthermore, instantaneous flow fields and large-scale vortical structures were predicted and are presented herein. These vortical structures were found to be responsible for the significant lateral exchange of mass and momentum in compound channels. [Copyright &y& Elsevier]

Abstract: Brain monoaminergic systems play critical roles in mood, cognition, emotion, reward, learning and attention, and aberrance in brain monoaminergic activity is associated with a variety of neuropsychiatric disorders/diseases. The present commentary focuses on trace amine-associated receptor 1 (TAAR1) and its potential regulatory roles in brain monoaminergic systems. TAAR1 was discovered in 2001 and has been established to be a G-protein-coupled receptor signaling through the cAMP pathway. This receptor is activated by a broad spectrum of agonists, although there are notable species differences in ligand efficacy and potency. TAAR1 is expressed and widely distributed in brain monoaminergic systems and co-localized with the dopamine transporter in a subset of dopaminergic neurons in rhesus monkey and mouse brain substantia nigra. TAAR1 activation by the common biogenic amines, the trace amine β-phenylethylamine and methamphetamine alters the monoamine transporter function in both mouse and rhesus monkey brain synaptosomes, suggesting a modulatory role for this receptor in the presynaptic regulation of monoaminergic activity. However, little is known about other functional roles of TAAR1 in the brain. With a purpose to promote further studies on this receptor, we herein discuss the recent findings that provide insights into the functional significance and biological relevance of this receptor as a modulator in brain monoaminergic systems. [Copyright &y& Elsevier]

Underground flooding events are being exacerbated due to the rapid expanding of underground space in urban and the extreme precipitation events by climate change. It is increasingly necessary to study hydrodynamics and instabilities of human on staircases in the flood-prone underground space for risk identification and disaster reduction. However, the turbulent complexity and complicated fluid-human interaction still challenge the study of flow structure and the calibration of human instability model. In this work, a hydrodynamic model coupled with the mechanics-based method was proposed to study fluid-human interactions and hazard risks on flooding stairways. Numerical validations show that the model can obtain reliable solutions of flow characteristics on staircases. It is found that there exists a jet flow downstream the rest platform and the critical region after the 3rd step downstream the platform is identified as a high risk area to cause sliding instability. The risk of sliding instability for a child is higher than that for an adult in jet flow region. In addition, results show that the downstream vortical flow structure and turbulent effect are obviously enhanced because of the interdict of jet flow by the human obstacle. [ABSTRACT FROM AUTHOR]

For the purpose of this paper, the in-house large-eddy simulation code, Hydro3D, is refined to study wave structure interaction. First of all, the code is used to develop a numerical wave tank capable of simulating accurately the generation, progression and damping of solitary waves in a tank. Then, Hydro3d is employed to simulate a previous laboratory experiment of a wave propagating over an infinitely wide flat plate. The code's accuracy is validated by comparing computed waterlevels and hydrodynamic forces on the plate with measured data for which good agreement is found for a number of conditions (i.e. varying wave steepness or plate submergence, respectively). Then the study is extended to investigate three-dimensional effects for which the infinitely wide plate is replaced by a finite square plate. It is found that the pressure difference between the lower and upper side of the plate drives a span-wise flow and creates unique flow structures and water-surface fluctuations near the plate due to the three-dimensionality of the problem. A further three-dimensional study is conducted for which the finite plate is fixed at an angle of attack in respect to the incident wave and variations in hydrodynamic forces and free-surface elevations are computed. Both vertical and horizontal forces are reduced when the plate is fixed at 45 ∘ degrees and minor water-level fluctuations appear, reflecting the pattern of the rotational flow near the plate edges. Plots of the velocity vectors, swirl-strength, pressure and wave elevation and acting forces reveal significant differences between an infinitely wide and a finite square plate subjected to a solitary wave. [ABSTRACT FROM AUTHOR]

A two-phase flow model is employed to study three-dimensional (3D) breaking of solitary waves over surface-piercing and submerged conical structures. Details of the wave pre-breaking, overturning, and post-breaking processes are included. The governing equations are discretized by the finite volume method and the PISO algorithm is utilized for the pressure-velocity coupling. The air–water interface is captured using a volume of fluid approach and the Cartesian cut-cell method is implemented to deal with the complex topography of the conical structures. The method is validated first using available experimental data of a solitary wave propagating over a surface-piercing conical island and good agreement between the experiment and simulation data is obtained. The model is then applied to study 3D breaking waves over a submerged conical structure, with 3D wave profiles and surface velocities being presented and discussed. The detailed 3D velocity fields, energy dissipation and transformation during the wave breaking process are presented. • A 3D two-phase flow model was employed to study breaking waves including pre-breaking, overturning, and post-breaking processes. • The model has been validated against available experimental results for conical island. • Detailed 3D characteristics of breaking waves over a submerged conical structure are studied. [ABSTRACT FROM AUTHOR]

• Numerical models are developed to study the acoustic pressure and the trajectory of microparticles in the device. • The enhanced acoustic pressure exerts higher acoustic radiation force on particles resulting in faster particle motion and higher manipulation throughput. • Acoustofluidic devices with more than one SAW transducer manipulate micro- and nano-particles more effectively. • SAW-SAW and PZT-SAW configurations produce significantly higher acoustic pressure and particle velocity in the microchannel. Acoustofluidic techniques are increasingly used to manipulate nano- and micro-particles in microfluidics. A wide range of acoustofluidic devices consisting of microchannels and acoustic sources have been developed for applications in biochemistry and biomedicine. In this work, two hybrid acoustofluidic devices are developed and modelled, including a double surface acoustic wave (SAW) transducer and a PZT-SAW transducer. The numerical study to these devices demonstrates a higher acoustic pressure present in the microchannel resulting in larger particle velocities in migration to the pressure nodes. The amplitude of the acoustic pressure and the pattern of the pressure distribution can be controlled in the hybrid transducers. By sweeping the height and width of the microchannel, one can identify an optimum dimension to produce intensive acoustic pressure in the PZT-SAW transducer. The particle trajectories reveal that both the SAW-SAW and PZT-SAW configurations produce significantly higher acoustic pressure and particle velocity in the microchannel. This work provides new insights to design acoustofluidic devices with more than one SAW transducer to effectively manipulate micro- and nano-particles. [ABSTRACT FROM AUTHOR]

The economic value of pear is determined by its intrinsic qualities, which are influenced by metabolites produced during the ripening process. Methyl jasmonate (MeJA), a hormone, plays an important role in plant metabolism. To date, few studies have investigated the molecular mechanism underlying the changes in metabolic pathways related to the internal quality of pear fruit after MeJA treatment. In this study, ultrahigh-performance liquid chromatography‒Q Exactive Orbitrap mass spectrometry (UHPLC‒QE‒MS) was used to determine the changes in metabolite contents in pear after MeJA treatment. MeJA treatment primarily activated carbohydrate metabolism and amino acid metabolism pathways. Through combined analysis of UHPLC‒QE‒MS data and whole-transcriptome data, the abovementioned pathways and each metabolite were analysed separately, and competitive endogenous RNA (ceRNA) and microRNA–transcription factor–target (miRNA–TF–target) regulatory networks were constructed. The core nodes of three genes (PEA, Pbr022732.1; GAA, Pbr035655.1; and miR8033-x) and two genes (SDS, Pbr031708.1; and novel-m6796-3p) were associated with the carbohydrate metabolism and amino acid metabolism pathways, respectively. The core mRNA nodes TCONS_00048038 and Pbr019584.1, the core miRNA node miR4993-x, the core lncRNA node TCONS_0004356, the core circRNA node novel_circ_001967 and the core transcription factor node TSO1 (Pbr025407.1) were identified via separate metabolite analyses. These findings elucidate the changes in metabolites related to fruit quality in 'Nanguo' pear and the relationships between the metabolites and genes, reveal the molecular mechanism underlying the response of MeJA treatment in pear fruit, and provide a theoretical basis for improving the internal quality of 'Nanguo' pear. • MeJA treatment affected the metabolite contents of pear fruit. • CeRNA and miRNA‒mRNA‒target networks reveal gene‒metabolite relationships. • Core genes regulating pathways and metabolites were identified. [ABSTRACT FROM AUTHOR]

This paper presents a computational methodology for the two and three dimensional numerical simulation of dense and dilute dispersed particles in multiphase gas–solid and liquid–solid flows. The model equations are based on the two fluids approximation, with closure terms for the fluid–solid drag interaction forces and the additional dense collisional terms arising from particle–particle interactions under the kinetic theory. These equations are discretized and solved using a novel unstructured mesh control volume-finite element framework, with an anisotropic mesh adaptivity capability. The methodology is applied to study the transport of sand particles of various sizes in fluidized beds, as well as particle segregation in a polydisperse system containing three solid particle sizes. [ABSTRACT FROM AUTHOR]

• A 3D non-hydrostatic model for submarine-landslide-generated waves is developed. • The discretized Poisson equation is symmetric and can be solved efficiently. • A wide range of tests including 2D and 3D landslide waves are simulated. • 3D feature of the generated tsunami wave can be revealed by the developed model. A three-dimensional (3D) non-hydrostatic model for simulating nonlinear and dispersive waves is extended to compute submarine-landslide-generated waves. The model uses a projection method to solve the 3D Navier-Stokes equations on a 3D grid system built from a two-dimensional (2D) horizontal mesh by adding several horizontal layers in the vertical direction. The free surface is efficiently captured by the so-called free surface equation. The bottom movement is incorporated in the model by specifying the kinematic boundary condition at the impermeable bottom. The extension does not alter the property of the discretized Poisson equation for non-hydrostatic pressure correction terms. Thus, it can also be solved efficiently by the preconditioned conjugate gradient method. A wide range of tests including 2D and 3D landslide waves are simulated. Comparisons between numerical results and experimental data and/or other model results are presented. It is found that a good agreement has been obtained for a range of landslide waves using a very small number of horizontal layers (e.g. three or five layers) and the proposed model can be considered as an attractive alternative to simulating submarine-landslide-generated waves. [ABSTRACT FROM AUTHOR]

The vacuolar H+-ATPase (V-ATPase) is a multi-subunit membrane protein complex, which plays pivotal roles in building up an electrochemical H+-gradient across tonoplast, energizing Na+ sequestration into the central vacuole, and enhancing salt stress tolerance in plants. In this study, a B subunit of V-ATPase gene, PbVHA-B1 was discovered and isolated from stress-induced P. betulaefolia combining with RT-PCR method. The RT-qPCR analysis revealed that the expression level of PbVHA-B1 was upregulated by salt, drought, cold, and exogenous ABA treatment. Subcellular localization analyses showed that PbVHA-B1 was located in the cytoplasm and nucleus. Moreover, overexpression of PbVHA-B1 gene noticeably increased the ATPase activity and the tolerance to salt in transgenic Arabidopsis plants. In contrast, knockdown of PbVHA-B1 gene in P. betulaefolia by virus-induced gene silencing had reduced resistance to salt stress. In addition, using yeast one-hybride (Y1H) and yeast two-hybride (Y2H) screens, PbbHLH62, a bHLH transcription factor, was identified as a partner of the PbVHA-B1 promoter and protein. Then, we also found that PbbHLH62 positively regulate the expression of PbVHA-B1 and the ATPase activity after salt stress treatment. These findings provide evidence that PbbHLH62 played a critical role in the salt response. Collectively, our results demonstrate that a PbbHLH62/PbVHA-B1 module plays a positive role in salt tolerance by maintain intracellular ion and ROS homeostasis in pear. • Salt stress induces the expression of PbVHA-B1 and PbbHLH62. • PbVHA-B1 physically interacts with PbbHLH62 to form a protein complex. • PbbHLH62 can bind to the PbVHA-B1 promoter to enhance the transcripts level and the activity of PbVHA-B1. • The PbbHLH62-PbVHA-B1 interaction synergistically confers salinity tolerance by regulating Na+/K+ homeostasis and ROS removal. [ABSTRACT FROM AUTHOR]

• The mutate greedy algorithm combines greedy strategy(MGA) with real-time feedback of mutation rate. • MGA can achieve fast convergence speed and high enhancement by balancing the contradiction between greedy strategy and population diversity. • There is only one parameter, i.e., population size, to adjust in the MGA. • The MGA structure is simple and can save many computational resources. Optical focusing through scattering media plays a significant role in various fields, such as medicine, communications, and detection. Over recent years, population optimization algorithms have been successfully applied to these fields with remarkable results. However, the current algorithms have limitations, such as offspring inheriting bad genes from their parent, parameter-tuning, and complex operation mechanisms. To address these challenges, we propose the mutate greedy algorithm (MGA), which innovatively combines greedy strategy with real-time feedback of mutation rate. MGA can achieve fast convergence speed and high enhancement by balancing the contradiction between greedy strategy and population diversity. There is only one parameter, i.e., population size, to adjust in the MGA. The MGA structure is simple and can save many computational resources. Our research is expected to advance wavefront shaping from laboratory to practical applications. [ABSTRACT FROM AUTHOR]

The discharge of wastewater into coastal waters can be simplified as a turbulent jet under waves and currents. A laboratory study has been carried out to measure the instantaneous flow field of a vertical round jet under wavy-crossflow environment using an improved particle image velocimetry (PIV) technique. The phase-averaged streamlines are found to be the most chaotic at the wave trough phase. Temporal variation in fluctuating turbulent kinetic energy is explored. Results indicate a lack of distinctive patterns in fluctuation turbulent kinetic energy across wave phases, particularly in far field. This suggests that wave phases marginally affect jet width expansion, especially in the far field. Spatial variations in turbulent kinetic energy are examined and crossflow and wave period are also considered. It is found that decreasing relative wave-orbital velocity to crossflow velocity R wc enhances maximum turbulent kinetic energy in the near field of the wavy-crossflow jet. • Flow field of a round jet in wavy-crossflow environment are measured using an improved PIV technique. • Turbulent properties inside the effluent cloud are higher than that outside the effluent cloud. • Maximum turbulence kinetic energy of jet in wavy-crossflow environment is small than that in crossflow near jet orifice. • Reduce wave-to-crossflow velocity ratio enhances maximum turbulent kinetic energy in near field of jet in wavy-crossflow. [ABSTRACT FROM AUTHOR]

Abstract Experimental results, based on two-dimensional (2-D) laboratory tests, for impulse waves generated by subaerial landslides of combined solid block and granular materials are presented in this study. The results are compared with those of individual models of pure solid block and granular landslides. By considering an identical slide mass and release height, the effect of the mass ratio m * on wave generation was investigated. The mass ratio is defined as m * = M B / M , where M B is the mass of the solid block, M = M B + M G is the total mass and M G is the mass of the granular portion. The experimental results show that the combined landslides with m * = 0.6 and 0.8 in this study generally produce much larger impulse waves in the impact zone compared with those triggered by pure solid block landslides (m * = 1) and pure granular landslides (m * = 0). This suggests that the primary wave amplitudes of impulse waves might have been underestimated in previous laboratory tests with solely solid or granular assemblies when using the same slide mass and release height. The larger primary wave amplitudes of the combined landslides compared with those of the pure solid block landslides are mainly attributed to the relatively large thickness of the combined landslides and the continuous motion of the granular portion, as the inside solid block stops at the hill slope toe. Compared with pure granular landslides, combined landslides generally have a larger Froude number and slide thickness, which account for the larger primary wave amplitudes. The latter plays a quantifiably more important role – nearly two times that of the former. The effects of the hill slope angle α , and the grain size of the granular materials D , were also studied in this work. Four different hill slope angles (α = 22.5°, 30°, 37.5° and 45°) and four different mean grain diameters (D = 5 mm, 10 mm, 20 mm and 30 mm) were tested. By comparing the measured maxima of the wavelet spectra obtained via a wavelet transform method with those reconstructed by means of the phase celerity of the solitary wave c s and the group celerity of linear wave c g (f), it is found that the measured maxima travel at either c s or c g (f), depending on the landslide type and the hill slope angle α. However, the celerity of the measured maxima for the high frequency is lower than c g (f) and c s for the impulse waves generated by combined landslides when α ≤ 37.5° in this study. Further investigations show that the wave amplitude decreases rapidly during wave propagation, following an exponential function. The decrease in the wave amplitude during propagation is mainly attributed to dispersion. Highlights • Impulse waves generated by combined block-granular landslides were investigated experimentally. • The effects of the mass ratio, hill slope angle and grain size on primary wave amplitudes were examined. • Block/granular landslide may underestimate waves if real landslides consist of block and grain materials with the same mass and release height. [ABSTRACT FROM AUTHOR]

As a popular method for modeling violent free surface flow, the incompressible Smoothed Particle Hydrodynamics (ISPH) based on the Lagrangian formulation has attracted a great attention worldwide. The Lagrangian ISPH solves the unsteady Navier-Stokes and continuity equations using the projection method, in which the pressure is obtained by solving the pressure Poisson's equation (PPE) that is the most time-consuming part in the ISPH procedure. In this paper, the Convolutional Neural Network (CNN) is combined with ISPH and used to predict the fluid pressure instead of solving the PPE directly. Although limited attempts of using CNN for solving the PPE in Eulerian formulation (referred to as the Eulerian CNN framework) in mesh-based methods are found in the public domain, the present model is the first ISPH model supported by CNN in a Lagrangian formulation. The proposed model overcome several challenges associated with combining CNN with ISPH, including selecting the input parameters, formulating the objective functions, producing the training dataset and dealing with boundary conditions. Two classic free surface problems, i.e. the dam breaking and the wave propagation, are simulated to evaluate the performance of the present model. Quantitative assessments of the numerical error in terms of both the free surface profile and the pressure field are carried out. The assessments show that the new model does not only give results with satisfactory accuracy, but also requires much less computation time for estimating pressure if the number of particles is large, e.g., 100 thousands particles that is usually required in the practical ISPH simulation for free surface flow. [ABSTRACT FROM AUTHOR]