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This paper deals with the closed-form solutions to the family of Boussinesq-like equations with the effect of spatio-temporal dispersion. The sine-Gordon expansion and the hyperbolic function approaches are efficiently applied to the family of Boussinesq-like equations to explore novel solitary, kink, anti-kink, combo, and singular-periodic wave solutions. The attained solutions are expressed by the trigonometric and hyperbolic functions including tan , sec , cot , csc , tanh , sech , coth , csch , and of their combination. In addition, the mentioned two approaches are applied to the aforesaid models in the sense of Atangana conformable derivative or Beta derivative to attain new wave solutions. Three-dimensional and two-dimensional graphs of some of the obtained novel solutions satisfying the corresponding equations of interest are provided to understand the underlying mechanisms of the stated family. For the bright wave solutions in terms of Atangana’s conformable derivative, the amplitudes of the bright wave gradually decrease, but the smoothness increases when the fractional parameters α and β increase. On the other hand, the periodicity increases for the periodic wave solutions. The attained new wave solutions can motivate applied scientists for engineering their ideas to an optimal level and they can be used for the validation of numerical simulation results in the propagation of waves in shallow water and other nonlinear cases. The performed approaches are found to be simple and efficient enough to estimate the solutions attained in the study and can be used to solve various classes of nonlinear partial differential equations arising in mathematical physics and engineering.

This article proposes a transdimensional (trans-D) geoacoustic inversion method adapted to range-dependent (RD) propagation tracks based on prior information from a high-resolution seismic survey. Most trans-D inversions to date model the seabed as a stack of range-independent homogeneous layers, with unknown geoacoustic parameters and an unknown number of layers. The proposed method models the seabed as an unknown number of homogeneous sediment layers with an RD thickness structure and applies an adiabatic normal-mode model to predict acoustic propagation. To do so, the method extrapolates trans-D seabed models proposed at the receiver position over the range of the propagation track using reflector-interface information from a seismic survey. The method is applied successfully to modal time–frequency dispersion data collected over an RD track during the 2017 Seabed Characterization Experiment (SBCEX).

Due to global warming, the decline in the Arctic sea ice has been accelerating over the last four decades, with a rate that was not anticipated by climate models. To improve these models, there is the need to rely on comprehensive field data. Seismic methods are known for their potential to estimate sea-ice thickness and mechanical properties with very good accuracy. However, with the hostile environment and logistical difficulties imposed by the polar regions, seismic studies have remained rare. Due to the rapid technological and methodological progress of the last decade, there has been a recent reconsideration of such approaches. This paper introduces a methodological approach for passive monitoring of both sea-ice thickness and mechanical properties. To demonstrate this concept, we use data from a seismic experiment where an array of 247 geophones was deployed on sea ice in a fjord at Svalbard, between March 1 and 24, 2019. From the continuous recording of the ambient seismic field, the empirical Green's function of the seismic waves guided in the ice layer was recovered via the so-called 'noise correlation function'. Using specific array processing, the multi-modal dispersion curves of the ice layer were calculated from the noise correlation function, and then inverted for the thickness and elastic properties of the sea ice via Bayesian inference. The evolution of sea-ice properties was monitored for 24 days, and values are consistent with the literature, as well as with measurements made directly in the field.

Based on three-wave method, abundant nonautonomous solutions with different wave structures of a 3D variable-coefficient generalized shallow water wave equation are presented. In this situation the basic configurations (characteristic, amplitude, and speed) of the nonautonomous waves mutate with time due to the effect of nonlinearity and dispersion. Discussions indicate the interaction between lump wave and a pair of resonance stripe solitons solutions, the interaction between lump wave and periodic wave solutions, and the breather-type periodic soliton solutions. The dynamic properties of the obtained solutions are demonstrated and analyzed graphically for different choices of the arbitrary functions in these solutions.

Long wave evolution on viscous films flowing under gravity down an inclined plate in the presence of an electrostatic field acting normal to the plate is described using new nonlinear models. First, an asymptotic expansion is applied to derive a strongly nonlinear evolution equation for the interfacial position in the long-wave limit, which retains terms up to second order in a small film parameter ( e ) and thus brings in dispersive effects, inclination-angle corrections for hydrostatic pressure, second-order contributions to inertia and electric stresses as well as the interaction of the last two. Two weakly nonlinear models (WNMs) for the disturbances with O ( e 2 ) amplitude are then derived, which account for distinct effects of hydrostatic pressure, inertia and dispersion for shallow and steep angles. We compare the linear stability results based on the second-order electrified Benney equation (BE) and the WNMs with realistic parameter values. It is shown that the growth rates coincide, while the phase speed from the WNMs is a good approximation of that from the BE for small wavenumbers only. The comparison of exact dispersion relations from the Orr–Sommerfeld (OS) problem with the linear results of the second-order BE takes a step towards understanding the validity range of the BE with non-local terms that approximates the full electrohydrodynamic coupling system describing the inclined electrified film flow. The pertinent OS results demonstrate that a decrease in electrode distance can diminish the critical Reynolds number ( R e ). Furthermore, at subcritical R e with a slightly supercritical electric field, the finite wavelength of the least stable mode has been estimated using an energy balance, whose amplitude will be governed by two coupled Ginzburg–Landau (GL) equations, derived using a multiple-scale analysis by taking higher-order problems into account. The numerical solutions of the leading-order GL equation demonstrate that close to the bifurcation, it can fully govern the temporal behaviour of the system.

Surface wave (SW) methods offer promising options for an effective and sustainable development of seismic exploration, but they still remain under-exploited in hard rock sites. We present a successful application of active and passive surface wave tomography for the characterization of the southern continuation of the Siilinjärvi phosphate deposit (Finland). A semi-automatic workflow for the extraction of the path-average dispersion curves (DCs) from ambient seismic noise data is proposed, including identification of time windows with strong coherent SW signal, azimuth analysis and two-station method for DC picking. DCs retrieved from passive data are compared with active SW tomography results recently obtained at the site. Passive data are found to carry information at longer wavelengths, thus extending the investigation depth. Active and passive DCs are consequently inverted together to retrieve a deep pseudo-3D shear-wave velocity model for the site, with improved resolution. The southern continuation of the mineralization, its contacts with the host rocks and different sets of cross-cutting diabase dikes are well imaged in the final velocity model. The seismic results are compared with the latest available geological models to both validate the proposed workflow and improve the interpretation of the geometry and extent of the mineralization. Important large-scale geological boundaries and structural discontinuities are recognized from the results, demonstrating the effectiveness and advantages of the methods for mineral exploration perspectives.

In MRI, deep neural networks have been proposed to reconstruct diffusion model parameters. However, the inputs of the networks were designed for a specific diffusion gradient scheme (i.e., diffusion gradient directions and numbers) and a specific b-value that are the same as the training data. In this study, a new deep neural network, referred to as DIFFnet, is developed to function as a generalized reconstruction tool of the diffusion-weighted signals for various gradient schemes and b-values. For generalization, diffusion signals are normalized in a q-space and then projected and quantized, producing a matrix (Qmatrix) as an input for the network. To demonstrate the validity of this approach, DIFFnet is evaluated for diffusion tensor imaging (DIFFnetDTI) and for neurite orientation dispersion and density imaging (DIFFnetNODDI). In each model, two datasets with different gradient schemes and b-values are tested. The results demonstrate accurate reconstruction of the diffusion parameters at substantially reduced processing time (approximately 8.7 times and 2240 times faster processing time than conventional methods in DTI and NODDI, respectively; less than 4% mean normalized root-mean-square errors (NRMSE) in DTI and less than 8% in NODDI). The generalization capability of the networks was further validated using reduced numbers of diffusion signals from the datasets and a public dataset from Human Connection Project. Different from previously proposed deep neural networks, DIFFnet does not require any specific gradient scheme and b-value for its input. As a result, it can be adopted as an online reconstruction tool for various complex diffusion imaging.

High-order staggered-grid finite-difference (SFD) schemes are preferred in elastic wave simulation for geophysical problems because they decrease the accumulation of error from grid dispersion. However, most SFD approaches reach high-order spatial but limited temporal accuracy. To tackle the issue, we develop a novel temporal and spatial high-accuracy elastic SFD scheme by selectively modifying the spatial operators of the original SFD stencil. This modification has three main advantages. First, it facilitates the design of a new SFD stencil with temporal and spatial accuracies to arbitrary even-order by a Taylor-series expansion method. Second, it helps boost the accuracy further by implementing a linear optimization method. Third, the new selectively modified SFD (SMSFD) stencil needs fewer float-point operations (FPOs) than the existing temporal high-order SFD stencil. We compare our new SMSFD scheme with spatial high-order and temporal-spatial high-order SFD schemes and show that our new elastic SMSFD scheme possesses better accuracy and stability and requires fewer FPOs than these methods.

A hypothetical value of an MHD parabolic started perpendicular plate along with rotation with unvarying mass dispersion on thermal radiation. The heat plate is elevated on T’W then promoted the centre near the close plate was about C’W. The plate hotness along with the concentration point next to the plate is lifted consistently. Dimension-less equivalence realized by applying the Laplace transmute method. This Analytic method of the issue tackled with the limit condition for heat and fixation is one with thermal radiation. The interpretation for temperature profile, concentration, and velocity outline is used several bodily criteria Grashof quantity for thermal and mass, warm air energy limitation, prandtl quantity, Schmidt quantity. The value speed steps up along mounting ideals of Grashof number for thermal (or) Grashof number for mass. The vogue is presently inverted with abiding by thermal radioactivity stricture.

The optimization of antenna parameters such as gain is an important aspect of all antenna design. In the context of leaky-wave antennas (LWAs), it is important to have accurate design rules for optimizing the gain of the antenna for practical finite-length structures. In this work, taking advantage of the recent formulas derived for the accurate evaluation of the beamwidth in finite-size 1-D unidirectional LWAs, we obtain optimum conditions for this general class of antennas. In particular, design rules for minimizing the beamwidth or maximizing the gain are obtained. The latter is evaluated with a fully analytical procedure through the definition of a correction function that improves the accuracy of the common gain–beamwidth relation. The effects of material losses are also discussed to show how they can affect the optimization procedure. These results apply to any 1-D unidirectional LWA, because no assumptions are made on the wavenumber dispersion, which is instead structure-specific. However, the optimization of two practical examples, namely a holey and a slitted LWA, is discussed to show practical application of the proposed design rules.

In this work, we consider a coupled nonlinear viscoelastic Kirchhoff equations with degenerate damping, dispersion and source terms. Under suitable hypothesis, we will prove that when the initial data are large enough (in the energy point of view), the energy grows exponentially and thus so the $ L^{2(p+2)} $-norm.

Publisher Copyright: Author We present design, simulation, and experimental characterization of dual-band frequency-diverse holograms for distributed beamforming. The holograms operate in the 50-75 GHz (WR-15) and 220-330 GHz (WR-3.4) bands for millimeter-and submillimeter-wave imaging. The holograms are designed to create a dispersive field in the region of interest (RoI) located 600 mm from the aperture. The holograms lie in the front end of an imaging setup and modulate the phase of the incident collimated beam from a parabolic mirror. The distributed beamforming enables interrogation of the RoI so that the measured reflection through the dispersive propagation path conveys the spatial information of the target. Different phase modulation schemes are evaluated, and two prototype holograms are manufactured. The dispersive operation and efficiency of the hologram are characterized with both simulations and measurements. The frequency diversity of the holograms is quantified using singular-value decomposition and spatial-spectral correlation coefficient methods. The results identified a design frequency of 120 GHz, a phase quantization step of π/2 radians, and an added phase of 1.9π radians as a good dispersion-efficiency compromise. A fully connected neural network is trained to localize a corner-cube reflector in the RoI illuminated by the hologram. The localization accuracy follows the diffraction-limited resolution and confirms the best performance for the hologram considered optimal in the design metrics.

Full-waveform inversion (FWI) serves as a useful tool to quantitatively investigate the properties of the subsurface. Presently, three-dimensional (3D) elastic FWI uses a finite-difference time-domain (FDTD) approach in numerical simulation. However, such an FDTD scheme often includes only second-order temporal approximations, causing errors in temporal dispersion in the case of a large time-stepping size. Such temporal dispersion will affect the inversion results and reduce the inversion quality. We introduce a unique 3D elastic FWI using a temporal fourth-order finite-difference approximation. A new quasi-stress–velocity elastic equation is solved by the temporal fourth-order and spatial arbitrary even-order FDTD method, and a novel inversion procedure for the convolutional objective function based on this equation is derived. The multiscale strategy is used to enhance the robustness of our algorithm. The forward modeling and FWI examples presented here demonstrate that our method can achieve modeling and inversion with a high degree of accuracy.

We report the initial results of an experimental investigation into the measurement of ocean surface currents with an ultrahigh frequency synthetic aperture radar (UHF SAR) that supports an along-track interferometric (ATI) mode. We compare results from two different approaches to the current measurement: analysis of wave dispersion in a time-sequence of subaperture images and standard ATI-SAR processing. We find that while both methods clearly show a surface velocity front over the north wall of the Gulf Stream, the change in velocity indicated by the dispersion method is significantly less than that indicated by ATI-SAR processing. We offer methodological and geophysical reasons for the observed differences.

Detecting corrosion damage is critical in the petrochemical industry as the wall thinning in tanks or pipelines may cause severe accidents, inducing loss of economics or even lives. Guided wave based tomography is a promising technique which can effectively estimate the remaining wall thickness based on the wave dispersion curves. In this work, we proposed a tomography method for structural health monitoring based the dispersive shear horizontal waves (SH1), which are excited by two antiparallel thickness-shear (d15) piezoelectric strips (APS). The probability factor and continuous condition are both introduced to the classic algebraic reconstruction technique (ART-PC) to achieve a convenient and efficient high quality reconstruction. Then the tomography experiment is conducted on a 6mm-thick aluminum plate with a 1.5mm-deep, 50mm diameter blind hole and the results show that the hole can be well reconstructed. Furthermore, the inversion image reconstructed by using ART-PC algorithm has a high accuracy and resolution, especially when compared with that reconstructed by using the classic algorithms. The proposed SH1 wave based tomography method in this work is expected to be widely used in petrochemical industries in near future.

Observation of dispersion in field situations has left three issues that may be better understood by applying advective transport phenomena. (1) In some experiments, the longitudinal dispersivity becomes constant with increasing pathlength and in other cases it remains growing. (2) Dispersivities reported from multiple comprehensive observations at a single site differ at similar pathlength in some cases more than a factor two. (3) The observed difference between the plume fronts and plume tails is not represented in the reported parameters. The analytic equations for advective transport phenomena at macro-scale of (De Lange 2019) describe the thickness of the affected flow-tube and the spread of the plume front and tail. The scale factor defines the size of the averaging domain and so of the initial phase. The new macro-scale correlation coefficient relates the growth of the longitudinal dispersivity beyond the initial phase to the aquifer heterogeneity. Using stochastic parameters for the aquifer heterogeneity, the parameters are quantified at fourteen field experiments in the USA, Canada and Europe enabling the comparison of calculated and reported final dispersivities. Using the quantified parameters, 146 reported and calculated dispersivities along the traveled paths show a good match. A dispersivity derived from the local plume growth may differ a factor of two from the aquifer-representative value. The growths of plume fronts and tails between two plume stages are assessed in fourteen cases and compared to calculated values. Distinctive parameters for the plume front and tail support better understanding of field situations. A user-ready spreadsheet is provided.

Shear wave elastography (SWE) is a method of evaluating mechanical properties of soft tissues. Most current implementations of SWE report the group velocity for shear wave velocity, which assumes an elastic, isotropic, homogenous and incompressible tissue. Local Phase Velocity Imaging (LPVI) is a novel method of phase velocity reconstruction that allows for accurate evaluation of shear wave velocity at specified frequencies. This method’s robustness was evaluated in 11 elastic and 8 viscoelastic phantoms using linear and curvilinear arrays. We acquired data with acoustic radiation force push beams with different focal depths and F-numbers and reconstructed phase velocity images over a wide range of frequencies. Regardless of phantom, push beam focal depth, and reconstruction frequency, using an F-number around 3.0 was found to produce the largest usable area in the phase velocity reconstructions. For elastic phantoms scanned with a linear array, the optimal focal depth, frequency range, and maximum region-of interest (ROI) were 20–30 mm, 100–400 Hz, and 2.70 cm(2), respectively. For viscoelastic phantoms scanned with a linear array, the optimal focal depth, frequency, and maximum ROI were 20–30 mm, 100–300 Hz, 1.54 cm(2), respectively. For the curvilinear array in the same phantoms; optimal focal depth, frequency range, and maximum ROIs were 45–60 mm, 100–400 Hz and 100–300 Hz, and 1.54 cm(2), respectively. Further work will be done to evaluate LPVI reconstructions from inclusion phantoms to simulate nonhomogeneous tissues. Additionally, LPVI will be evaluated in larger volume phantoms to account for wave reflection from the containers when using the curvilinear array.

Although the effects of the concrete heterogeneity on the seismic response of concrete gravity dams have been explored based on random finite element method, the results of different studies vary greatly and there are few quantitative studies on the effects. In addition, the correlation between concrete modulus and strength is usually ignored, which is a departure from the reality. In this study, the effects of the concrete heterogeneity on the nonlinear seismic response of concrete gravity dams under different input ground motions are systematically studied based on random field theory. The dispersion and uncertainty of the seismic responses and the damage pattern are quantified. In addition, the effects of the correlation between concrete modulus and strength are also investigated and quantified based on the cross-correlated random fields simulation method. It is found that the effects of the concrete heterogeneity on the nonlinear dynamic response of concrete dams are strongly dependent on the input seismic motions, which provides an explanation for the conflicts in the previous studies. The results also show that the correlation between concrete modulus and strength has important effects on the dispersion of the seismic response and damage pattern of concrete gravity dams. Under certain ground motions, ignoring the correlation may underestimate the failure probability of the dams.

The seismic assessment of steel gabled frames (SGFs) is of great importance and a key problem in any high-seismicity region, given the enormous costs of industrial equipment and the remarkable number of individuals working in such structures. Near-fault ground motions, especially their strike-normal component that usually contain a long-period pulse in the velocity time-history, can lead to a significant demand in these structures in comparison to the far-fault ground motions. Although numerous studies have confirmed the destructive effects of near-fault ground motions on concrete and steel structures, no research has been devoted to the impact of this ground motions on steel gabled structures yet. Hence, the findings of this research can unveil novel dimensions of such structures. In this regard, in the present paper, an incremental dynamic analysis (IDA) was conducted for the first time on four SGFs with the spans of 20 m and 60 m and heights of 6 m and 12 m using far-fault ground motions (OR set), as well as near-fault ground motions along the strike-normal and strike-parallel components (SN and SP sets, respectively). The results were presented in the form of multi-record IDA curves, summarized IDA curves, probabilistic seismic demand models (PSDMs) and probabilistic seismic demand analysis (PSDA) curves. The outcomes indicated that compared to far-fault ground motions, near-fault ground motions (especially pulse-like ones) produced significant changes on the seismic behavior of long-period SGFs, resulting in raises the changes of stiffness and demand sensitivity, reduces the dynamic capacity, enhances the data dispersion and uncertainty, and increases the mean annual frequencies (MAFs) in such structures. However, the results of PSDA analysis showed that under any type of ground motion (OR, SN and SP), short-period SGFs are more vulnerable than long-period SGFs and should be prioritized for retrofitting. Finally, the importance of combining the hazard curve of the study region with the results of IDA analysis of the structure in evaluating the seismic behavior of SGFs is highlighted.

The utilization of urban underground space in a smart city requires an accurate understanding of the underground structure. As an effective technique, Rayleigh wave exploration can accurately obtain information on the subsurface. In particular, Rayleigh wave dispersion curves can be used to determine the near-surface shear-wave velocity structure. This is a typical multiparameter, high-dimensional nonlinear inverse problem because the velocities and thickness of each layer must be inverted simultaneously. Nonlinear methods such as simulated annealing (SA) are commonly used to solve this inverse problem. However, SA controls the iterative process though temperature rather than the error, and the search direction is random; hence, SA always falls into a local optimum when the temperature setting is inaccurate. Specifically, for the inversion of Rayleigh wave dispersion curves, the inversion accuracy will decrease with an increasing number of layers due to the greater number of inversion parameters and large dimension. To solve the above problems, we convert the multiparameter, high-dimensional inverse problem into multiple low-dimensional optimizations to improve the algorithm accuracy by incorporating the principle of block coordinate descent (BCD) into SA. Then, we convert the temperature control conditions in the original SA method into error control conditions. At the same time, we introduce the differential evolution (DE) method to ensure that the iterative error steadily decreases by correcting the iterative error direction in each iteration. Finally, the inversion stability is improved, and the proposed inversion method, the block coordinate descent differential evolution simulated annealing (BCDESA) algorithm, is implemented. The performance of BCDESA is validated by using both synthetic data and field data from western China. The results show that the BCDESA algorithm has stronger global optimization capabilities than SA, and the inversion results have higher stability and accuracy. In addition, synthetic data analysis also shows that BCDESA can avoid the problems of the conventional SA method, which assumes the S-wave velocity structure in advance. The robustness and adaptability of the algorithm are improved, and more accurate shear-wave velocity and thickness information can be extracted from Rayleigh wave dispersion curves.

This study identifies efficient earthquake intensity measures (IMs) for seismic performances and fragility evaluations of the reactor containment building (RCB) in the advanced power reactor 1400 (APR1400) nuclear power plant (NPP). The computational model of RCB is constructed using the beam-truss model (BTM) for nonlinear analyses. A total of 90 ground motion records and 20 different IMs are employed for numerical analyses. A series of nonlinear time-history analyses are performed to monitor maximum floor displacements and accelerations of RCB. Then, probabilistic seismic demand models of RCB are developed for each IM. Statistical parameters including coefficient of determination (R2), dispersion (i.e. standard deviation), practicality, and proficiency are calculated to recognize strongly correlated IMs with the seismic performance of the NPP structure. The numerical results show that the optimal IMs are spectral acceleration, spectral velocity, spectral displacement at the fundamental period, acceleration spectrum intensity, effective peak acceleration, peak ground acceleration, A95, and sustained maximum acceleration. Moreover, weakly related IMs to the seismic performance of RCB are peak ground displacement, root-mean-square of displacement, specific energy density, root-mean-square of velocity, peak ground velocity, Housner intensity, velocity spectrum intensity, and sustained maximum velocity. Finally, a set of fragility curves of RCB are developed for optimal IMs.

Hazardous chemical gases will spread rapidly after leakage. For emergency response to that, people need to obtain the information of wind and pollutant in time. However, it takes a lot of time to calculate the flow in large-scale urban areas by numerical simulation. Therefore, reduced-order model(ROM) is developed to improve the efficiency. In this paper, we propose a model based on proper orthogonal decomposition(POD) and radial basis function(RBF) interpolation. We validate the model by calculating the wind field and the pollutant propagation process in a 144 square kilometer area of Beijing. The results show that ROM can reduce CPU times by more than 99% at the cost of only 0.1% information loss, comparing with the traditional approach of computational fluid dynamics(CFD).

With the rapid development and application of the laser ultrasonic technology in nondestructive testing in recent years, thermo-elastic waves in diverse waveguides have captured a multitude of attention. However, they are mainly focused on one-dimensional and half-space structures. In engineering, there are also a lot of two-dimensional structures, such as joist steel, straight bars and rings. However, rare attention is paid on thermo-elastic waves in these structures. Accordingly, in the context of Green–Lindsay (G–L) generalized thermo-elasticity theory, a modified double orthogonal polynomial approach is exploited to investigate thermo-elastic waves in bars with a rectangular cross-section. The dispersion, attenuation and displacement curves of thermo-elastic waves are illustrated. Subsequently, influences of the cross-section size and relaxation time on wave characteristics are analyzed. Results indicate that the cross-section size and relaxation time have a significant influence on thermo-elastic waves. The phase velocity and attenuation values of thermal wave modes decrease as the relaxation time increases. These results obtained can be utilized to guide the laser ultrasonic nondestructive testing for this kind of structures.

Design/optimization of the tuned mass damper (TMD) system may not always lead toward robust performance if uncertainties exist. In view of this, a stochastic design of multiple TMD (MTMD) systems has been proposed in the present study taking into account various uncertainties. Taylor-expansion is used to perturb the objective function facilitating stochastic design/optimization. An interval-extension is used to observe the effect of uncertainties of different levels. The Lyapunov equation is used in the design of TMD systems by minimizing the dispersion of displacement of the primary system. The present work takes into account a model of generalized MTMD system. Seismic excitation is considered as a random process in the form of both: (a) stationary Kanai–Tajimi (KT) filter and (b) stationary Gaussian white noise directly applied to the base of structure. A numerical investigation is carried out to observe the consequences of uncertainties on the optimum design of MTMD parameters for both the excitation models (with and without incorporating Kanai–Tajimi filter). Efficiency of the MTMD systems (with variation of number of MTMD mass-units) is compared under various levels of uncertainties. Finally, some significant earthquake records are utilized toward more realistic understanding on the performance of stochastic design of TMD/MTMD systems under seismic excitation with various levels of uncertainties.

Most of the surface wave-based geophysical methods require an accurate estimate of the shear wave velocity (Vs) for geotechnical site investigation. The Vs gives a measure of shear modulus which is an important engineering parameter and also owns implications for delineating weak zones and cavities. Geotechnical investigation of such zones is imperative to avoid hazards related to high building construction. Among different surface wave-based geophysical methods, the multi-channel analysis of surface waves (MASW) is most widely used technique for geotechnical investigation by measuring in situ Vs. The present work focuses on MASW data acquisition and processing for accurate estimation of Vs by using dispersion analysis and different iteration-based inversion techniques (i.e., Monte Carlo and least square approaches). The proposed methodology is investigated at two sites in Abu Dhabi, UAE, using 24-channel seismograph network. The obtained results suggest that Monte Carlo approach is more efficient and reliable for Vs profile estimation and is recommended for geotechnical investigation. Monte Carlo approach-based results of the MASW velocity-profiles at both sites confirmed cavities and their geometries within the subsurface. Furthermore, the identified cavities are well in agreement with the trail borehole data, thus improving the confidence level of the obtained results. The characterization of the soil of both the sites and its implications are also presented with the help of NEHRP and IBC codes.

Wavetubes are employed for measurements of acoustic properties in various fluids. The ability to manipulate and control the frequency-dependent boundary impedance of the tube improves the estimation accuracy. Passive solutions, which use composite materials to change the boundary impedance, enable one to realize a finite combination of boundary impedances. In this paper, the tube boundary impedance is tuned at will by using two loudspeakers. The suggested method operates in the presence of dispersion by estimating, in real-time, a parametric reduced-order model using a multichannel least mean square algorithm. The identified model is fed to a nonlinear, adaptive control algorithm to realize modal traveling wave ratio (TWR) control. It has been noted that the TWR is smooth and parabolic across closed regions in the parameter space, thus assuring the convergence of the nonlinear control. Several methods to estimate the TWR gradient are considered and compared based on an analytical model of a rigid impedance tube. An experimental case study utilizing an air-filled impedance tube with two loudspeakers is presented. The results demonstrate the ability to control the dynamics of the principal acoustic mode at will, thus enabling one to set the desired tube's boundary impedance.

We study theoretically the transverse Anderson localization of light in the simplest geometry, where the p-polarized wave propagates along the layers in the randomly stratified dielectric and evanesces exponentially in the direction across the layers. In this case, there exist two reasons for the localization of the wave in the direction transverse to its propagation: the usual evanescent wave confinement and the Anderson mechanism related to the randomness of the spatial distribution of permittivity. We solve the problem using the retarded-Green-function formalism in the Born approximation and show that, for fixed values of the wave frequency ω and wavenumber q, the random inhomogeneity results in the weakening of the wave localization. In the case of the surface plasmon-polaritons (SPPs) propagation, the Anderson mechanism changes the dispersion law for SPPs, moving the dispersion curves away from the light line. Therefore, the localization depth varies in different ways when increasing the disorder, depending on which of the values, wave vector q or frequency ω, is fixed. Namely, the localization depth increases for given q, but it decreases for given ω.

We reveal that external potentials in completely integrable higher-order nonautonomous nonlinear dynamical systems can be expressed as an infinite power series with time-varying coefficients. As the representative example, the generalized Hirota equation is introduced in this work in the framework of the nonisospectral generalization of the Inverse Scattering Transform method with associated spectral parameter varying in accordance with the Riccati equation. We demonstrate that accelerating and self-compressing nonautonomous solitons of the introduced model conserve the soliton main feature to interact elastically both in the linear, parabolic, and cubic external potentials, and are controlled only if the varying dispersion and nonlinearity satisfy to the conditions of the exact integrability.

We compare several lowest-order finite element approximations to the problem of elastodynamics of thin-walled structures by means of dispersion analysis, which relates the parameter frequency-times-thickness ( f d ) and the wave speed. We restrict to analytical theory of harmonic front-crested waves that freely propagate in an infinite plate. Our study is formulated as a quasi-periodic eigenvalue problem on a single tensor–product element, which is eventually layered in the thickness direction. In the first part of the paper it is observed that the displacement-based finite elements align with the theory provided there are sufficiently many layers. In the second part we present novel anisotropic hexahedral tangential-displacement and normal–normal-stress continuous (TDNNS) mixed finite elements for Hellinger–Reissner formulation of elastodynamics. It turns out that one layer of such elements is sufficient for f d up to 2000 [kHz mm]. Nevertheless, due to a large amount of TDNNS degrees of freedom the computational complexity is only comparable to the multi-layer displacement-based element. This is not the case at low frequencies, where TDNNS is by far more efficient since it allows for rough anisotropic discretizations, contrary to the displacement-based elements that suffer from the shear locking effect.

The systematic discrepancies in both tsunami arrival time and leading negative phase (LNP) were identified for the recent transoceanic tsunami on 16 September 2015 in Illapel, Chile by examining the wave characteristics from the tsunami records at 21 Deep-ocean Assessment and Reporting of Tsunami (DART) sites and 29 coastal tide gauge stations. The results revealed systematic travel time delay of as much as 22 min (approximately 1.7% of the total travel time) relative to the simulated long waves from the 2015 Chilean tsunami. The delay discrepancy was found to increase with travel time. It was difficult to identify the LNP from the near-shore observation system due to the strong background noise, but the initial negative phase feature became more obvious as the tsunami propagated away from the source area in the deep ocean. We determined that the LNP for the Chilean tsunami had an average duration of 33 min, which was close to the dominant period of the tsunami source. Most of the amplitude ratios to the first elevation phase were approximately 40%, with the largest equivalent to the first positive phase amplitude. We performed numerical analyses by applying the corrected long wave model, which accounted for the effects of seawater density stratification due to compressibility, self-attraction and loading (SAL) of the Earth, and wave dispersion compared with observed tsunami waveforms. We attempted to accurately calculate the arrival time and LNP, and to understand how much of a role the physical mechanism played in the discrepancies for the moderate transoceanic tsunami event. The mainly focus of the study is to quantitatively evaluate the contribution of each secondary physical effect to the systematic discrepancies using the corrected shallow water model. Taking all of these effects into consideration, our results demonstrated good agreement between the observed and simulated waveforms. We can conclude that the corrected shallow water model can reduce the tsunami propagation speed and reproduce the LNP, which is observed for tsunamis that have propagated over long distances frequently. The travel time delay between the observed and corrected simulated waveforms is reduced to

The numerical modeling of spatio-temporal evolution of lagoon has an important role in predicting the behaviour of these systems. Knowing the concentration of the pollutant field distribution in time and space contributes significantly to the prediction of exceptional phenomena. The purpose of this paper is to simulate the transport and dispersion of salt at Nokoue Lake. To this end, the 2D hydrodynamic model SMS (Surface Water Modeling System) has been used. Results showed that in flood period the freshwater inflows produce a net seaward transport, while in low water period the tides lead to periodic seaward and landward transport. The developed numerical model is useful for predicting pollutants transport in this system, for water quality management of the Nokoue Lake, and therefore, fight against eutrophication.

Subsurface rocks contain pores and cracks of various sizes. The cracked porous medium elastic wave theory that describes wave propagation characteristics due to the pore-crack interaction is extended to include cracks of different aspect ratios. The extended theory is applied to model P- and S-wave velocity data of dry and fluid-saturated rock under pressure loading conditions, so as to determine the pore-aspect-ratio spectrum through an inversion procedure. The inversion result is consistent with that from the scanning electron microscope analysis, showing significant improvement versus previous inversion. The inverted pore-aspect-ratio spectrum is input into the wave theory to predict the velocity dispersion of the rock in the full frequency range. The predicted dispersion and its variation trend with pressure agree with the data measured in the (2–200, 106) Hz range at various differential pressures, whereas the modeling using a single-aspect-ratio theory has difficulty matching the data. This research work provides not only a method for analyzing the pore structure characteristics of rocks from the laboratory ultrasonic velocity data, but also a way to predict the seismic wave dispersion from the data.

Shear wave dispersion imaging is a novel ultrasound-based technique, which analyzes the speed of different shear wave components depending on their frequency. The dispersion of shear wave speed correlates with the viscosity of the liver parenchyma. The aim of this prospective study was to evaluate the use of shear wave dispersion imaging in focal liver lesions in the non-cirrhotic liver.Patients with unclear focal liver lesions in B-mode ultrasound were prospectively assigned to shear wave dispersion imaging (m/s/kHz). Measurements were conducted within the lesion and in the liver parenchyma of the right liver lobe using an intercostal window. Histology and contrast-enhanced ultrasound served as the reference for the characterization of the lesions.Out of 46 patients included in this study, 24 had liver metastases and 22 had benign liver lesions. Benign lesions consisted mostly of hemangiomas (n=12) and focal nodular hyperplasia (n=8). Malignant lesions showed significantly lower shear wave dispersion (13.0±2.45 m/s/kHz) compared to benign tumors (15.2±2.74 m/s/kHz, p0.01). In further subgroup analysis, the difference was significant for hemangiomas (15.32±2.42 m/s/kHz, p=0.04) but not for FNHs (14.98±3.36 m/s/kHz, p=0.38). The dispersion of reference liver parenchyma did not differ significantly between the groups (p=0.54).The quantification of viscosity by shear wave dispersion is a new parameter for the characterization of focal liver lesions with higher dispersion values in hemangiomas and lower dispersion values in metastases. However, it cannot differentiate reliably between benign and malignant lesions.Die Scherwellendispersion ist ein neues ultraschallbasiertes Verfahren, welches die Geschwindigkeit verschiedener Scherwellenanteile in Abhängigkeit ihrer Frequenz misst. Diese Dispersion der Scherwellen korreliert mit der Viskosität des Leberparenchyms. Ziel dieser prospektiven Studie war es, die Anwendung von Scherwellendispersion in fokalen Leberläsionen in der nichtzirrhotischen Leber zu untersuchen.Patienten mit fokalen Leberläsionen wurden prospektiv mit Scherwellendispersion (m/s/kHz) untersucht. Die Messungen wurden in der Läsion und im Parenchym des rechten Leberlappens mit interkostalem Zugang durchgeführt. Die Einordnung der Leberläsionen erfolgte mittels Kontrastmittelsonografie oder Histologie.Von insgesamt 46 eingeschlossenen Patienten hatten 24 Lebermetastasen und 22 gutartige Läsionen. Benigne Veränderungen waren vor allem Hämangiome (n=12) und fokale noduläre Hyperplasien (n=8). Metastasen zeigten eine signifikant niedrigere Dispersion (13,0±2,45m/s/kHz) als gutartige Leberläsionen (15,2±2,74m/s/kHz; p0,01). In der Subgruppenanalyse war nur der Unterschied zu Hämangiomen signifikant (15,32±2,42m/s/kHz; p=0,04), nicht aber zu FNH (14,98±3,36m/s/kHz; p=0,38). Die Messwerte des Leberparenchyms zwischen den einzelnen Gruppen waren nicht signifikant unterschiedlich (p=0,54).Die Bestimmung der Viskosität mit Scherwellendispersion ist ein neuer Parameter zur Charakterisierung fokaler Leberläsionen mit höheren Werten in Hämangiomen und niedrigeren Werten in Metastasen. Er ermöglicht jedoch keine zuverlässige Unterscheidung zwischen benignen und malignen Läsionen.

The effects of different human walking patterns on contaminant dispersion in residential kitchens were investigated through computational fluid dynamics simulation with the dynamic mesh method. A tracer gas experiment was performed to verify the feasibility and accuracy of the simulation method. Flow characteristics induced by human walking were minutely described, and the transient capture efficiency of the range hood was adopted to assess the impact of human walking quantitatively. Human walking parallel to a counter, human walking parallel to a counter manned by another human, and human walking toward a counter were studied. Results showed that the mutual effect of the wake and thermal plume caused contaminant dispersion and decreased the performance of the range hood as the human subject walked beside the counter. Even a standing person operated ahead the counter, the wake would affect the thermal plume in a certain extent. The decrement of capture efficiency approached 0.5 in the most unfavorable situation. Moreover, the coaction of the positive/negative pressure zone and impinging air jet drew the thermal plume to the human body. The fluctuation of capture efficiency in this condition was moderate relative to that for the human walking pattern beside the counter. This research could provide a comprehensive overview of different human walking patterns and their impact on residential kitchens and thereby facilitate the maintenance of kitchen air quality.

In this paper, the inherent self-similarity between seismic characteristics and the dynamic behavior of a concrete gravity dam under decomposed near-fault ground motions is investigated. The representative low- and high-frequency components were decomposed using the continuous wavelet transform method to explore their effects on the dam response. The Koyna concrete gravity dam system was used as the basis for a numerical model. A series of dam dynamic responses under near-fault motion with and without pulse properties were obtained by numerical analyses. The relationship between the proposed dimensionless indices (intensity measure ratio (ΦIM), pulse period ratio (T1/Tp)), and response ratio (ΨEDP, m) was established to study the inherent self-similarity in the dynamic behavior of dams, which has an explicit physical significance with smaller dispersion. The response proportions of two main frequency components in the original near-fault record were revealed. Furthermore, a series of new threshold values were calculated based on the intersection of the pulse and high-frequency ratios, and the range of influence of the low- and high-frequency components was quantitatively divided. Finally, a predictive model was proposed for the dam responses to near-fault ground motions containing the proposed dimensionless indices that exhibited reasonable patterns. The pulse-like seismic characteristics and seismic responses to near-fault ground motions were analyzed and selected in the context of sensitivity, inherent self-similarity, threshold point, and regression error. Results show that the self-similarity between Φ S a ( T 1 ) , ΦASI and ΨDVR,pulse, Ψ DVR n , p u l s e is superior to that of other parameter ratios, indicating that more attention should be given to the role of intensity and pulse parameters in practical concrete dam seismic design.

In most applications of post-tensioning, especially for bridge girders, the cross section over which the post-tensioning acts is not rectangular. Since the design of the box girder anchorage zone is not currently addressed in any code provisions, a detailed investigation of the three-dimensional (3D) spreading of the tendon force in flanged sections is required. To accomplish this objective, a computer-based tool is developed for plotting load paths in 3D bodies, from which the flow of forces in the box-girder anchorage zone can be clearly visualized. It is found that the 33.7-degree criterion is appropriate to describe the dispersion of the tendon force in the box-girder. Meanwhile, planar strut-and-tie models are built to approximate the flow of forces in orthogonal planes of the box section. As a useful supplement to the current design codes, direct equations are established for the design of the box-girder anchorage zone. Finally, a case study is carried out to find the cause of cracking in a span-by-span constructed box-girder bridge. The large transverse tensile stress in the bottom flange is primarily caused by the post-tensioning of web tendons, indicating the importance of 3D effects in the box-girder anchorage zone.

A manufacturing study of a 0.372 THz 8-fold (8F) helically corrugated interaction region (HCIR) and measurement of its wave dispersion characteristics are reported. This demonstrates the structure’s suitability as the electron beam / electromagnetic wave interaction region in a high power frequency tunable Gyroresonant THz source. The 8F HCIR has an eigenmode, which is ideal for broadband tuning, created by the coupling of the TE61 and TE23 modes. Maximum power handling of 14 times larger than a 3-fold HCIR at the same frequency is calculated. A TE11 to TE61 7-fold (7F) helically corrugated waveguide (HCW) mode converter, needed to measure the wave dispersion of the 8F HCIR, was designed and constructed. Negative aluminium mandrels of the 7F HCW mode converter and 8F HCIR were manufactured. Copper structures were constructed through electroforming. The measured wave dispersion of the 0.372 THz 8F HCIR agreed well with simulated dispersion characteristics.

The constrained interpolation profile (CIP) method is one of the finite-difference methods. In principle, the CIP method can suppress numerical dispersion and instability even when a relatively coarse grid is used. However, the M-type and C-type CIP methods, proposed as of today, can deal with neither conductor in the air nor imperfectly conducting ground. In this article, the CIP method is improved and extended to be capable of considering the presence of conductors in air and imperfectly conducting ground. This extended CIP (X-CIP) method does not use the direction-splitting technique, which is used in the conventional CIP methods and makes it difficult to represent conductors in air. The X-CIP method is applied to the simulations of lightning electromagnetic pulses over a perfectly or imperfectly conducting ground and associated surges on conductors in air, and the computed results are compared with those computed theoretically or using the finite-difference time-domain method.

Coherent flow structures and pollutant dispersion in a spanwise-long street canyon are investigated using a parallelized large-eddy-simulation model. Low- and high-concentration branches, starting from the downwind top corner and upwind bottom corner, respectively, are detected in the time-averaged field of pollutant concentration, and detailed structures of in-canyon flow and pollutant dispersion following the two branches are demonstrated. When turbulent eddies impinge on the upper downwind wall, low- and high-concentration blobs with U-shaped flow structures appear and move downward. The downdrafts tilt away from the downwind bottom corner and impinge on the canyon bottom, driving horizontally diverging flows. Cellular structures of low-concentration centres and high-concentration edges are induced by the downdrafts and diverging flows. The diverging flows push low-concentration air toward the downwind and upwind building walls, resulting in local divergence and convergence of pollutants on both walls. Time series of pollutant concentration at multiple points illustrate that pollutant concentration at the pedestrian level is highly sensitive to the diverging flows. The multiresolution spectra show that time scales of variations of pollutant concentration and vertical velocity component increase from the canyon top to the pedestrian-level centre, indicating longer time-scale flow structures are dominant inside the street canyon. The multiresolution cospectra also show that the time scale of vertical turbulent transport of pollutants increases from the canyon top to the pedestrian-level centre. At the two bottom corners, however, short and long time-scale transports occur together, confirming that the low-concentration diverging flows transport pollutants downward while short time-scale turbulence transports pollutants upward.

In areas of intensive ship traffic, ships pass every 10 min. Considering the amount of ship traffic and the predicted increase in global maritime trade, there is a need to consider all types of impacts shipping has on the marine environment. While the awareness about, and efforts to reduce, chemical pollution from ships is increasing, less is known about physical disturbances, and ship-induced turbulence has so far been completely neglected. To address the potential importance of ship-induced turbulence on, e.g., gas exchange, dispersion of pollutants, and biogeochemical processes, a characterisation of the temporal and spatial scales of the turbulent wake is needed. Currently, field measurements of turbulent wakes of real-size ships are lacking. This study addresses that gap by using two different methodological approaches: in situ and ex situ observations. For the in situ observations, a bottom-mounted acoustic Doppler current profiler (ADCP) was placed at 32 m depth below the shipping lane outside Gothenburg harbour. Both the acoustic backscatter from the air bubbles in the wake and the dissipation rate of turbulent kinetic energy were used to quantify the turbulent wake depth, intensity, and temporal longevity for 38 ship passages of differently sized ships. The results from the ADCP measurements show median wake depths of 13 m and several occasions of wakes reaching depths > 18 m, which is in the same depth range as the seasonal thermocline in the Baltic Sea. The temporal longevity of the observable part of the wakes had a median of around 10 min and several passages of > 20 min. In the ex situ approach, sea surface temperature was used as a proxy for the water mass affected by the turbulent wake (thermal wake), as lowered temperature in the ship wake indicates vertical mixing in a thermally stratified water column. Satellite images of the thermal infrared sensor (TIRS) onboard Landsat-8 were used to measure thermal wake width and length, in the highly frequented and thus major shipping lane north of Bornholm, Baltic Sea. Automatic information system (AIS) records from both the investigated areas were used to identify the ships inducing the wakes. The satellite analysis showed a median thermal wake length of 13.7 km (n=144), and the longest wake extended over 60 km, which would correspond to a temporal longevity of 1 h 42 min (for a ship speed of 20 kn). The median thermal wake width was 157.5 m. The measurements of the spatial and temporal scales are in line with previous studies, but the maximum turbulent wake depth (30.5 m) is deeper than previously reported. The results from this study, combined with the knowledge of regional high traffic densities, show that ship-induced turbulence occurs at temporal and spatial scales large enough to imply that this process should be considered when estimating environmental impacts from shipping in areas with intense ship traffic.

The propagation of the hybrid slow waves in the new helix traveling wave tube, including a dielectric rod, gas plasma layer, and helix sheath is examined. It is assumed that the plasma is strongly ...

Turbidity from glacial meltwater limits light penetration with potential ecological consequences. Using profiles of temperature, conductivity, and turbidity, we examine the physical processes driving changes in the epilimnetic turbidity of Carpenter Reservoir, a long and narrow, glacier-fed reservoir in southwest British Columbia, Canada. Following the onset of permanent summer stratification, the relatively dense inflows plunged into the hypolimnion, and despite the high glacial load entering the reservoir, the epilimnion cleared due to particle settling. Using a one-dimensional (longitudinal) diffusion equation for a decaying substance to describe the variation in epilimnetic turbidity, we obtain two nondimensional parameters: the epilimnetic inflow parameter, $$\mathcal {I}$$ I , a measure of the turbidity flux into the epilimnion; and the dispersion parameter, $${\mathcal {D}}$$ D , a measure of longitudinal dispersion. In the case of Carpenter Reservoir: $$\mathcal {I}\ll 1$$ I ≪ 1 , indicating that turbidity declines over the summer; and $${\mathcal {D}}\ll 1$$ D ≪ 1 , indicating a strong gradient in turbidity along the epilimnion. Using our theoretical formulation of epilimnetic turbidity variations in conjunction with monthly field surveys, we compute the particle settling velocity ($${\sim}{0.25}\,{\hbox {m}\,\hbox {d}^{-1}}$$ ∼ 0.25 m d - 1 ), the longitudinal dispersion coefficient (50–70 $${\hbox {m}^{2}\,\hbox {s}^{-1}}$$ m 2 s - 1 ), and the flux of turbid water into the epilimnion ($${\sim }1{\%}$$ ∼ 1 % of the total inflow). Our approach is applicable to other reservoirs and can be used to investigate changes in turbidity in response to changes in $$\mathcal {I}$$ I and $${\mathcal {D}}$$ D .

We use a 5-h-long experiment with 182 vertical 2-Hz velocity sensors deployed on the surface to characterize noise before and during a hydraulic fracturing monitoring experiment in the Potiguar Basin, NE Brazil. We observe that the seismic noise is mainly from electromagnetic inductions and machinery vibration near the wellhead, and within 2 km of the array center from pumpjacks, pipelines, roads, and industrial facilities. We investigate the origin of the main recorded noise features using amplitude decay analysis and beamforming. We also report resonance composed of a body wave coming from the treatment wellhead area, which is only present when the injection takes place and is most likely associated with body-wave energy coming from the wellhead. To assess the utility of such a data set to retrieve the shallow velocity of the area using ambient noise seismic interferometry (ANSI), different strategies were employed to cross-correlate and stack the data: classical geometrical normalized cross-correlation (CCGN), phase cross-correlation (PCC), linear stacking and time-frequency phase-weighted stacking (tf-PWS). Because of the unsuitable distribution of the noise source and geometry of acquisition, spurious arrivals arise in the correlograms. We propose a simple method to attenuate these unwanted effects, which consists of applying a linear moveout (LMO) correction, stacking the data in the shot domains, and f-k filtering. The correlograms and their correspondent dispersion curves are significantly improved.

In this paper, we propose a numerical boundary treatment for simulating shock propagation in the fractional KdV-Burgers equation, based on a machine learning strategy. Numerical boundary treatment is particularly challenging due to the nonlinear and global interaction among the fractional diffusion, convection and dispersion. We select a suitable number of boundary points and interior points, and correct the numerical value at the boundary ones by linear combination of those at the interior ones. The large set of parameters are trained from a numerical reference shock solution connecting the end states 1 and 0, by ridge regression. Numerical tests demonstrate that the boundary treatment is effective in reflection suppression, and preserves the correct shock speed even under perturbed initial profile. Furthermore, using the above parameters, we construct a modified boundary treatment to simulate a range of different end states, with effectiveness checked numerically.

A low-level-jet (LLJ) event that occurred over a coastal area in complex terrain is analyzed to investigate its effect on the dispersion of potential air pollutants released in the area. The atmospheric model RAMS (Regional Atmospheric Modeling System) is employed with a high vertical resolution close to the surface, adopting a rarely used nesting approach, in order to allow a detailed analysis of the flow and to characterize the specific features of the LLJ. After a comparison with meteorological variables measured by radiosondes, numerical experiments are performed adding a scalar tracer in the simulation. As a first test, the tracer is distributed uniformly throughout the domain to follow the dynamics of the LLJ and its effect on the tracer dispersion. Then, continuous releases from virtual point sources are simulated to address their possible impact in the area under LLJ conditions. This allows the identification of “hotspots” of pollutant accumulation due to very local circulations and convective cells that develop from the combined effect of terrain-induced flow and the interaction of the LLJ flow with complex topography. An original mass analysis is applied on the dispersion results for an advanced exploration of the LLJ impact on the tracer. The RAMS model provides reliable results demonstrating that with which atmospheric numerical models are useful tools with which to study LLJ dynamics and their effect on local circulation and pollutant dispersion.

Xin et al. (2019) presented 3D seismic velocity models (VP and VS) of crust and uppermost mantle of continental China using seismic body-wave travel-time tomography, which are referred to as Unified Seismic Tomography Models for Continental China Lithosphere 1.0 (USTClitho1.0). Compared with previous models of continental China, the VP and VS models of USTClitho1.0 have the highest spatial resolution of 0.5°–1.0° in the horizontal direction and are useful for better understanding the complex tectonics of continental China. Although USTClitho1.0 is implicitly constrained by surface-wave data by using the VS model from surface-wave tomography and the converted VP model as initial models for body-wave travel-time tomography, the predicted surface-wave dispersion curves from USTClitho1.0 do not fit the observed data well. Here, we present updated 3D VP and VS models of the continental China lithosphere (USTClitho2.0) by joint inversion of body-wave arrival times and surface-wave dispersion data. Compared with the previous joint inversion scheme of Zhang et al. (2014), similar to Fang et al. (2016), it is further improved by including the sensitivity of surface-wave dispersion data to VP in the new joint inversion system. As a result, the shallow VP structure is also better imaged. In addition, the new joint inversion scheme considers the large topography variations between the eastern and western parts of China. Thus, USTClitho2.0 better resolves the upper-crustal structure of the Tibetan plateau. Compared with USTClitho1.0, USTClitho2.0 fits both body-wave arrival times and surface-wave dispersion data. Thus, the new velocity models are more accurate and can serve as a better reference model for regional-scale tomography and geodynamic studies in continental China.

We consider a Fermi–Pasta–Ulam (FPU) chain with the homogeneous fully nonlinear interaction potential which describes the propagation of acoustic wave in chains of touching beads without precompression. From the quasi-continuum approximation of the FPU chain, we first derive out a new type of wave equation which includes a second degree logarithmic nonlinear term. By finding an integrable factor equation, we obtain its Gaussian solitary wave solution. The result shows that if the effect of logarithmic nonlinearity can be balanced with the dispersion, the Gaussian solitary waves do exist for the second degree logarithmic wave equation in real physical models.

In this communication, a paralleled interior penalty discontinuous Galerkin time-domain method based on the vector wave equation (IPDG-WE) combining with a generalized dispersive material (GDM) model is introduced. In addition, the auxiliary differential equation (ADE) technique is employed to establish a universal solution for scattering analysis of dispersive structures in a wide frequency range. The proposed method presents great characteristics of energy conservation and the optimal convergence rate even in low-order bases and exhibits promising competitiveness in CPU time and memory usage compared with the traditional Maxwell’s equations-based discontinuous Galerkin time-domain (DGTD-ME) method. Numerical simulations are executed to demonstrate the accuracy and efficiency of the proposed method, which realize twice the memory and triple the CPU time reductions.

The fractional derivative method is used to take wave dispersion into account in the wave equation when describing the propagation of gravitational soliton waves on the surface of deep water. This approach is similar to that used to obtain the Korteweg–de Vries equation for solitons on the surface of shallow water, where the dispersion term in the wave equation is the third derivative of the velocity. It provides an alternative to the well-known approach of Zakharov and others based on the model of the nonlinear Schrodinger equation. The obtained nonlinear integral equation can be solved numerically.

Summary This work presents a novel technology for azimuth-dependent facies analysis (Facies Analysis versus Azimuth — FACIVAZ) to improve the prediction of hydrocarbon-saturated permeable fractures in terrigenous carbonate reservoirs. The analysis is performed in the depth domain along high-resolution, full-azimuth, angle domain common image gathers created by the EarthStudy 360™ Local Angle Domain (LAD) imaging system. The amplitude and phase preservation of the seismic reflectivities obtained by this imaging system is crucial to the proposed analysis. Prior to the facies analysis, the general orientation and intensity of the target fracture systems are analysed and characterized by azimuth-dependent velocity and amplitude analyses (VVAZ and AVAZ) performed along these LAD gathers. The remaining effects of the azimuth-dependent (and frequency-dependent) absorption and dispersion on the LAD gather events are then detected and further connected to the rate of the existing oil-saturated fractures within the reservoirs. The examples presented in this article show the effectiveness of the proposed FACIVAZ technology in accurately predicting the distribution of seismic facies in target production areas associated with oil-saturated fractured reservoirs in Western Siberia and Middle Volga. The results strongly agree with the corresponding facies characteristics measured in the boreholes along the reservoir area, and therefore serve as valuable information for the drilling decisions of new wells.