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the nonlinear acoustic wave spectroscopy and defectometry (nawsd) technique is found to be an efficient tool for monitoring intricate and complex defects in composite structures due to its better resolution and accuracy compared to the traditional methods. local defect resonance (ldr) is one of such methods based on am... | detection of local defect resonance frequencies using bicoherence analysis |
time-domain brillouin scattering (tdbs) uses ultrashort laser pulses to (i) generate coherent acoustic pulses of picoseconds duration in a solid sample and (ii) follow their propagation in order to image material inhomogeneities with the axial resolution that can be deeply sub-optical, to nm-scale, and the lateral one ... | 3d characterization of individual grains of coexisting high-pressure h2o ice phases by time-domain brillouin scattering |
after more than a decade of recurring tsunamis, identification of tsunami deposits, a part of hazard characterization, still remains a challenging task that is not fully understood. the lack of sufficient monitoring equipment and rare tsunami frequency are among the primary obstacles that limit our fundamental understa... | numerical simulations of the 2004 indian ocean tsunami deposits' thicknesses and emplacements |
in the context of acoustic or elastic wave propagation, the non-periodic asymptotic homogenization method allows one to determine a smooth effective medium and equations associated with the wave propagation in a given complex elastic or acoustic medium down to a given minimum wavelength. by smoothing all discontinuitie... | fast fourier homogenization for elastic wave propagation in complex media |
a boulder stone, a common geological feature in south china, is referred to the remnant of a granite body which has been unevenly weathered. undetected boulders could adversely impact the schedule and safety of subway construction when using tunnel boring machine (tbm) method. therefore, boulder detection has always be... | multi-hole seismic modeling in 3-d space and cross-hole seismic tomography analysis for boulder detection |
this study addresses the local m-fractional radhakrishnan-kundu-lakshmanan (rkl) equation by utilizing the extended rational sine-cosine/sinh-cosh methods. we give the constraint conditions which guarantee the existence of the valid solitons and other solutions to the studied model. the reported solutions may be useful... | the solitary wave solutions to the fractional radhakrishnan-kundu-lakshmanan model |
tsunamis propagating along the ocean surface generate internal gravity waves which can be detected in the atmosphere and ionosphere using airglow or total electron content (tec) measurements. since the late 1960s, the summation of the seismic normal modes of the earth allows to simulate the seismic ground motions measu... | tsunami modeling with solid earth-ocean-atmosphere coupled normal modes |
significance: diffuse correlation spectroscopy (dcs) is an optical technique that measures blood flow non-invasively and continuously. the time-domain (td) variant of dcs, namely, td-dcs has demonstrated a potential to improve brain depth sensitivity and to distinguish superficial from deeper blood flow by utilizing pu... | development of a monte carlo-wave model to simulate time domain diffuse correlation spectroscopy measurements from first principles |
complex high-value jointed structures such as aero-engines are carefully designed and optimized to prevent failure and maximise their life. in the design process, physically-based numerical models are employed to predict the nonlinear dynamic response of the structure. however, the reliability of these models is limite... | ultrasonic monitoring of friction contacts during shear vibration cycles |
in this study, a waveform modification method was proposed using a self-designed heating device combined with the split hopkinson pressure bar (shpb) technique for determination of dynamic behaviors of rock at high temperature. firstly, the temperature gradient distribution on the incident bar was measured according to... | a waveform modification method for testing dynamic properties of rock under high temperature |
we acquired measurements of four observable parameters of refracted signals received from the ionosphere (doppler shift, doppler spectrum, number of rays, and signal amplitude) with the oblique hf doppler technique in the city of harbin during the super typhoon lekima event of 4-12 august 2019. the ionospheric response... | disturbances in the ionosphere and distortion of radio wave characteristics that accompanied the super typhoon lekima event of 4-12 august 2019 |
we consider the quantum ising chain with uniformly distributed random antiferromagnetic couplings (1 ≤ji≤2 ) and uniformly distributed random transverse fields (γ0≤γi≤2 γ0 ) in the presence of a homogeneous longitudinal field, h . using different numerical techniques (density-matrix renormalization group, combinatorial... | reentrant random quantum ising antiferromagnet |
we analyse random errors (variances) in cross-correlations of ambient seismic noise in the frequency domain, which differ from previous time domain methods. extending previous theoretical results on ensemble averaged cross-spectrum, we estimate confidence interval of stacked cross-spectrum of finite amount of data at e... | frequency domain analysis of errors in cross-correlations of ambient seismic noise |
in this paper, we present results from the spectropolarimetric follow-up of photometrically selected candidate magnetic b stars from the mobster (magnetic ob[a] stars with tess: probing their evolutionary and rotational properties) project. out of four observed targets, one (hd 38170) is found to host a detectable surf... | mobster - iv. detection of a new magnetic b-type star from follow-up spectropolarimetric observations of photometrically selected candidates★ |
in this paper, we propose a weighted runge-kutta (rk) discontinuous galerkin (wrkdg) method for wavefield modelling. for this method, we first transform the seismic wave equations in 2-d heterogeneous anisotropic media into a first-order hyperbolic system, and then combine the discontinuous galerkin method (dgm) with a... | a weighted runge-kutta discontinuous galerkin method for wavefield modelling |
while the influence of dipolar interactions on the spin-wave dispersion in ferromagnets with localized magnetic moments has been studied in detail, similar studies in itinerant electron systems are rather scarce due to experimental difficulties. using the newly developed neutron larmor precession technique mieze in a l... | dipolar interactions in fe: a study with the neutron larmor precession technique mieze in a longitudinal field configuration |
with the development of the post-tensioning technique, prestressed concrete structures have been widely used in civil engineering. to ensure the long-term effectiveness of the prestressed tendon, the grouting quality of the tendon duct is one of the important factors. however, it is still a challenge to monitor the gro... | finite element analysis of grouting compactness monitoring in a post-tensioning tendon duct using piezoceramic transducers |
seismoelectric measurements are conducted with a synthetic porous rock sample to model an ocean exploration. two kinds of seismoelectric coupling signals, that is, the interfacial em wave signal and the coseismic electric signal, have been recorded by the electrodes buried inside a rock sample instead of those located ... | measurements of the seismoelectric responses in a synthetic porous rock |
the mw 6.0 earthquake that hit central italy on 2016 august 24 caused an abnormally high level of destruction in the town of amatrice. in order to clarify the role of site response in causing such a disaster, a series of ambient noise recordings acquired in the aftermath of the event are analysed here to identify site ... | multitemporal analysis of ambient noise polarization to characterize site response in the town of amatrice, shattered by the 2016 central italy earthquake |
acoustic emission (ae) testing and lamb wave inspection techniques have been widely used in non-destructive testing and structural health monitoring. for thin plates, the aes arising from structural defect development (e.g., fatigue crack propagation) propagate as lamb waves, and lamb wave modes can be used to provide ... | modal decomposition of acoustic emissions from pencil-lead breaks in an isotropic thin plate |
in recent years, nonlinear ultrasonic techniques have been developed rapidly for defect detection and characterization at its early development stage. in this paper, non-collinear shear wave mixing is used for fatigue crack detection and characterization, exploring how orientation and size may be determined. this is ac... | fatigue crack inspection and characterisation using non-collinear shear wave mixing |
in this paper, the generalized fifth-order variable-coefficients sawada-kotera equation arising in coastal seas, fjords, lakes, and the atmospheric boundary layer is studied by using the symmetry method. as a result, four-vector fields are obtained and a commutative lie group of transformations. then, by using suitable... | lie group analysis and novel solutions for the generalized variable-coefficients sawada-kotera equation |
this paper presents an original approach to local time-space grid refinement for the numerical simulation of wave propagation in models with localized clusters of micro-heterogeneities. the main features of the algorithm are the application of temporal and spatial refinement on two different surfaces; the use of the em... | local time-space mesh refinement for simulation of elastic wave propagation in multi-scale media |
this book gives a concise introduction to the basic techniques needed for the theoretical analysis of the maxwell equations, and filters in an elegant way the essential parts, e.g., concerning the various function spaces needed to rigorously investigate the boundary integral equations and variational equations. the boo... | the mathematical theory of time-harmonic maxwell's equations: expansion-, integral-, and variational methods |
the exploitation of orbital angular momentum (oam) is proposed to design circular-support continuous aperture distributions and concentric-ring arrays for target-localization applications. the proposed approach allows generating a single isolated null of the field in the target direction, which is of interest with resp... | synthesis of orbital angular momentum antennas for target localization |
this paper presents a new hybrid modeling technique for the efficient simulation of guided wave generation, propagation, and interaction with damage in complex composite structures. a local finite element model is deployed to capture the piezoelectric effects and actuation dynamics of the transmitter, while the global ... | hybrid local fem/global lisa modeling of damped guided wave propagation in complex composite structures |
in this paper, we consider random phase fluctuations imposed during wave propagation through a turbulent plasma (e.g. ionosphere) as a source of additional noise in interferometric visibilities. we derive expressions for visibility variance for the wide field of view case (fov ∼10°) by computing the statistics of fresn... | scintillation noise in widefield radio interferometry |
marchenko methods are a suite of geophysical techniques that convert seismograms of energy created by surface sources and measured by surface receivers into seismograms that would have been recorded by a virtual receiver at an arbitrary point inside the subsurface—an operation called redatuming. in principle these reda... | marchenko methods in a 3-d world |
the particle filter (pf) has shown great potential for on-line fatigue crack growth prognosis by combining crack measurements from structural health monitoring (shm) techniques. in this method, a key problem is to construct the mapping between the feature extracted from shm signals and the crack size. however, this map... | on-line updating gaussian process measurement model for crack prognosis using the particle filter |
with the advent of additive manufacturing, lattice structures can be printed with precisely controlled geometries. in this way, it is possible to realize porous samples with specific acoustic and thermoacoustic characteristics. however, to this aim and prior to the manufacturing process, it is fundamental to have a des... | acoustic and thermoacoustic properties of an additive manufactured lattice structure |
this work deals the construction of novel soliton solutions to the atangana-baleanu (ab) fractional system of equations for the ion sound and langmuir waves by using sardar-subequation method (ssm). the outcomes are in the form of bright, singular, dark and combo soliton solutions. these solutions have wide application... | novel soliton solutions to the atangana-baleanu fractional system of equations for the isalws |
surface winds from southern ocean cyclones generate large waves that travel over long distances (>1,000 km). wave generation regions are often colocated with enhanced air-sea fluxes and upper ocean mixing. ocean wave spectra contain information about storm wind speed, fetch size, and intensity at their generation si... | estimating southern ocean storm positions with seismic observations |
the so-called site effects caused by superficial geological layers may be responsible for strong ground motion amplification in certain configurations. we focus here on the industrialized tricastin area, in the french rhône valley, where a nuclear site is located. this area lies above an ancient rhône canyon whose lith... | estimation of the local seismic amplification on an industrialized site in the french rhône valley |
backprojection (bp) of teleseismic p waves is a powerful tool to study the evolution of seismic radiation of large earthquakes. the common interpretations on the bp results are qualitative comparisons with earthquake kinematic observations, such as the evolution of slip on the fault and rupture velocity. however, the d... | relating teleseismic backprojection images to earthquake kinematics |
we report on bidirectional coronal reconnection outflows reaching ±200 km s-1 as observed in an active region with the si iv and c ii spectra of the interface region imaging spectrograph (iris). the evolution of the active region with an emerging flux, a failed filament eruption, and a jet is followed in solar dynamica... | bidirectional reconnection outflows in an active region |
transient electrokinetic effects may generate conversions between seismic and electromagnetic energy in fluid-filled poroelastic media. two resulting seismoelectric signals have been predicted and identified: on the one hand electric fields accompanying seismic waves and on the other hand electromagnetic disturbances g... | a novel approach for seismoelectric measurements using multielectrode arrangements: ii—laboratory measurements |
a circular sectored core cladding structured photonic crystal fiber (pcf) is presented in this article, where core and cladding are sectored by few number of rectangles. the air fragments of core and cladding are constructed with circular manner that can facilitate the fabrication process. to design the porous core pcf... | design and characterization of a circular sectored core cladding structured photonic crystal fiber with ultra-low eml and flattened dispersion in the thz regime |
various techniques have emerged in the past few years for localizing the acoustic source in an anisotropic plate. the wave front shape-based approach, one of the recent additions to this field of research, has the advantage of circumventing the unrealistic assumption of a straight line wave propagation path through an ... | square-shaped sensor clusters for acoustic source localization in anisotropic plates by wave front shape-based approach |
a novel full wavefield processing method by using fully convolutional neural networks is presented. the full wavefield of propagating lamb waves in the fibre-reinforced composite plate was simulated by the parallel spectral element method. it resembles a full wavefield measurements acquired on a surface of the plate by... | full wavefield processing by using fcn for delamination detection |
we study the dynamics of modulated ionic waves in a microtubule modeled by a nonlinear rlc transmission line (tuszynski et al., 2004; sataric et al., 2009). we show through the application of a reductive perturbation technique that the network can be reduced in the continuum limit to the dissipative nonlinear schröding... | dynamics of modulated waves in a nonlinear microtubule rlc transmission line |
seismological detection methods are traditionally based on picking techniques. these methods cannot be used to analyse emergent signals where the arrivals cannot be picked. here, we detect and locate seismic events by applying a beamforming method that combines multiple body-wave phases to usarray data. this method exp... | detection and analysis of a transient energy burst with beamforming of multiple teleseismic phases |
we devise the first symplectic hamiltonian hybridizable discontinuous galerkin (hdg) methods for the acoustic wave equation. we discretize in space by using a hamiltonian hdg scheme, that is, an hdg method which preserves the hamiltonian structure of the wave equation, and in time by using symplectic, diagonally implic... | symplectic hamiltonian hdg methods for wave propagation phenomena |
the underwater acoustic screens made of periodically perforated rubber layers with metal plates are often used to enhance reflections and reduce transmissions of sound in water, under high hydrostatic pressure. previous studies have tended to focus on the acoustic response of finite-thickness structures of the screens,... | on wave propagation and attenuation properties of underwater acoustic screens consisting of periodically perforated rubber layers with metal plates |
we propose the use of smartphone-based slow-motion video analysis techniques as a valuable tool for investigating physics concepts ruling mechanical wave propagation. the simple experimental activities presented here, suitable for both high school and undergraduate students, allows one to measure, in a simple yet rigor... | using high speed smartphone cameras and video analysis techniques to teach mechanical wave physics |
an analytical method is proposed in this paper to study the effect of time-varying reentry plasma sheath on the instantaneous polarization statistic property of electromagnetic (em) waves. based on the disturbance property of the hypersonic fluid, the spatial-temporal model of the time-varying reentry plasma sheath is ... | instantaneous polarization statistic property of em waves incident on time-varying reentry plasma |
resolving atomic scale details while capturing long-range elastic deformation is the principal difficulty when solving contact mechanics problems with computer simulations. fully atomistic simulations must consider large blocks of atoms to support long-wavelength deformation modes, meaning that most atoms are far remov... | green's function method for dynamic contact calculations |
the electromagnetic wave propagation velocity at low radio frequencies is an important input parameter for lightning location systems that use time of arrival (toa) method. this velocity is normally fixed at or near the speed of light. however, this study finds that the radio waves from two submarine communication tran... | variable phase propagation velocity for long-range lightning location system |
the techniques of propagating spin-wave spectroscopy and current-induced spin-wave doppler shift are applied to a 20-nm-thick fe/mgo(001) film. the magnetic parameters extracted from the position of the spin-wave resonance peaks are very close to those tabulated for bulk iron. from the zero-current propagating wave for... | spin-wave propagation and spin-polarized electron transport in single-crystal iron films |
anisotropy and inhomogeneity of carbon fiber reinforced polymers (cfrps) result in that many traditional non-destructive inspection techniques are inapplicable on the delamination evaluation. this letter introduces eddy current pulsed phase thermography (ecppt) for cfrps evaluation considering volumetric induction heat... | eddy current pulsed phase thermography considering volumetric induction heating for delamination evaluation in carbon fiber reinforced polymers |
we propose a holographic projection system that achieves high image quality, brightness, and light efficiency. using a novel, to the best of our knowledge, light-efficiency loss function, we are able to concentrate more light on the projection region and improve display brightness compared with conventional projectors.... | high-brightness holographic projection |
we report on the spin-wave propagation along a magnonic waveguide with a local area of decreased magnetization, which is induced by heating produced with a focused laser spot. a phase-sensitive brillouin light scattering technique is used to image how the spin wave propagates along the waveguide with a local heat lands... | frequency-selective spin-wave propagation in magnonic waveguide with a local laser-heated region |
this study employs contemporary and precise computational techniques to obtain innovative solitary wave solutions for the (3 + 1)-dimensional kadomtsev-petviashvili (k p ) equation, which characterizes the behavior of long waves with small amplitudes compared to wavelengths in horizontally stratified fluids. the model ... | horizontal stratification of fluids and the behavior of long waves |
the water adsorption into pore spaces in brittle rocks affects wave velocity and transmitted amplitude of elastic waves. experimental and theoretical studies have been performed to characterize moisture-induced elastodynamic variations due to macroporous effects; however, little attention has been paid to the manner in... | laboratory acousto-mechanical study into moisture-induced changes of elastic properties in intact granite |
shear wave elastography (swe) is expected to be a noninvasive monitoring method of high-intensity focused ultrasound (hifu) treatment. however, conventional swe techniques encounter difficulty in inducing shear waves with adequate displacements in deep tissue. to observe tissue coagulation at the hifu focal depth via s... | monitoring of high-intensity focused ultrasound treatment by shear wave elastography induced by two-dimensional-array therapeutic transducer |
magnetic chemically peculiar stars of the main sequence can present rotational periods as long as many decades. here we report the results of an observational campaign started in 2001 aimed at establishing these very long periods from the variability of the integrated magnetic field modulus, the so-called surface magne... | twenty-year monitoring of the surface magnetic fields of chemically peculiar stars |
an underwater portable radio antenna operating in the 50 mhz band and efficient for launching surface electromagnetic waves at the seawater/air interface is presented. the antenna operation is based on the field enhancement at the antenna tip and on an impedance matching antenna enclosure, which is filled with de-ioniz... | surface wave based underwater radio communication |
a quantitative ultrasound technique with the advantages of an axial transmission measurement was applied in this study for the characterization of ultrasonic waves in the mhz range. this study focuses on the evaluation and effective detection of shear waves in bone plates. subsequently, wave propagation in a homogeneou... | characterization of shear waves in cortical bone using the axial transmission technique |
the acoustic properties of ca3ta(ga1- x al x )3si2o14 (ctgasx) were experimentally studied as a function of the al substitution content x in the ranges from x = 0 to 0.50. five specimens, x-, y-, z-, 35°y-, and 140°y-cut, were prepared from each crystal of ctgasx (x = 0, 0.25, and 0.50) grown by the czochralski techniq... | dependence of acoustic property on al substitution for ca3ta(ga1- x al x )3si2o14 single crystals |
in this paper we implement the stretched-coordinate perfectly matched layer (pml) technique in [28] to emulate full power absorption outside the simulation domain for time-harmonic electromagnetic wave propagation in presence of gyrotropic dielectric tensor and curved geometry relevant for magnetized plasma devices. we... | perfectly matched layers for time-harmonic transverse electric wave propagation in cylindrical and toroidal gyrotropic media |
numerous δ sct and γ dor pulsators are identified in the region of the hertzsprung-russell diagram that is occupied by chemically peculiar magnetic ap stars. the connection between δ sct and γ dor pulsations and the magnetic field in ap stars is however not clear: theory suggests for magnetic ap stars some critical fie... | searching for magnetic fields in pulsating a-type stars: the discovery of a strong field in the probable δ sct star hd 340577 and a null result for the γ dor star hr 8799 |
dynamic mechanical metamaterials (mms) are artificial media composed of periodic micro-structures, designed to manipulate wave propagation. modeling and designing mms can be computationally demanding due to the broad design space spanned by the geometric and material parameters. this work aims to develop a generalized ... | reduced order modeling of dynamic mechanical metamaterials for analysis of infinite and finite systems |
a novel torsional wave sensor designed to characterize mechanical properties of soft tissues is presented in this work. elastography is a widely used technique since the 1990s to map tissue stiffness. moreover, quantitative elastography uses the velocity of shear waves to achieve the shear stiffness. this technique exh... | performance study of a torsional wave sensor and cervical tissue characterization |
sensor networks have become more popular in recent years, now featuring plenty of options and capabilities. notwithstanding this, remote locations present many difficulties for their study and monitoring. high-frequency (hf) communications are presented as an alternative to satellite communications, being a low-cost an... | analysis of the ordinary and extraordinary ionospheric modes for nvis digital communications channels |
among many multiple attenuation methods, parabolic radon transform has been widely used due to its efficiency and effectiveness. however, there are two factors that restrict the application of radon transform: (1) the smearing caused by finite seismic acquisition aperture and discrete sampling of seismic data and (2) t... | 3d high-order sparse radon transform with l 1-2 minimization for multiple attenuation |
ultrasonic inspection is a widely used nondestructive testing approach in industrial fields for more accurate life prediction and efficient management strategies of critical structural components. however, it is quite challenging to detect a kind of micro-defect, whose size is much smaller than the ultrasonic wavelengt... | micro-defect imaging with an improved resolution using nonlinear ultrasonic lamb waves |
we propose an experimental approach to directly detect the acoustic radiation induced static component (sc) of primary longitudinal (l) wave propagation in solids using an ultrasonic pitch-catch technique, where a low-frequency ultrasonic transducer is used to detect the sc generated by the co-propagating primary l-wav... | an experimental approach for detection of the acoustic radiation induced static component in solids |
it is quite important for the detection and evaluation of material early degradation in order to ensure the durability and integrity of the key engineering components. the collinear wave mixing method is an effective and promising technique capable of detecting and localizing damage in materials. this research reports ... | evaluating and locating plasticity damage using collinear mixing waves |
ray tracing codes are useful to study the electromagnetic wave propagation and absorption in the geometrical optics approximation. in magnetized fusion plasma community, most ray tracing codes assume the plasma density and temperature be functions of the magnetic flux and study waves only inside the last closed flux su... | boray: a ray tracing code for various magnetized plasma configurations |
nonlinear scattering of ultrasonic waves by closed cracks subject to contact acoustic nonlinearity (can) is determined using a 2d finite element (fe) coupled with an analytical approach. the fe model, which includes unilateral contact with coulomb friction to account for contact between crack faces, provides the near-f... | analytical extension of finite element solution for computing the nonlinear far field of ultrasonic waves scattered by a closed crack |
focused ultrasound (fus) is an established technique for non-invasive surgery and has recently attracted considerable attention as a potential method for non-invasive neuromodulation. while the pressure waves in fus procedures have been extensively studied in this context, the accompanying shear waves are often neglect... | transcranial focused ultrasound generates skull-conducted shear waves: computational model and implications for neuromodulation |
currently, finite element method is the most widely used method for seismic analysis of underground tunnels. however, the finite element method has an apparent difficulty in modelling unbounded soils, therefore, artificial boundaries are often used to solve this problem, but it becomes much more complicated when the un... | a fe-ibe method for linearized nonlinear soil-tunnel interaction in water-saturated, poroelastic half-space: i. methodology and numerical examples |
optical coherence tomography (oct) can map the stiffness of biological tissue by imaging mechanical perturbations (shear waves) propagating in the tissue. most shear wave elastography (swe) techniques rely on active shear sources to generate controlled displacements that are tracked at ultrafast imaging rates. here, we... | diffuse shear wave imaging: toward passive elastography using low-frame rate spectral-domain optical coherence tomography |
nowadays components made of unidirectional composite materials are largely diffused in many engineering fields, such as automotive, railways, marine and aerospace. main drawback of this class of materials lies in their low out-of-plane properties making them very sensible to impulsive loads such as impact events. after... | high velocity impact on generic cfrp blade specimen: baseline free method for impact localisation and damage assessment on complex structures |
wave number vectors k and minimum cyclotron resonant electron energies emin of electromagnetic ion cyclotron (emic) waves are analyzed via the phase differencing technique by using magnetospheric multiscale mission data. it is demonstrated that the phase differencing method provides an estimate of the dominant wave num... | examining wave vector and minimum cyclotron resonant electron energy of emic waves with magnetospheric multiscale mission |
we study the fluctuations of the light emitted by two identical incoherent point sources in a disordered environment. the intensity-intensity correlation function and the speckle contrast, obtained after proper temporal and configurational averaging, encode the relative distance between the two sources. this suggests t... | speckle fluctuations resolve the interdistance between incoherent point sources in complex media |
remote triggering of very low-frequency (vlf) earthquakes in the nankai subduction zone by surface waves from a moderate to large, distant earthquake was examined using a bayesian approach. the triggering of another type of tectonic slow earthquake/tremor and slow slip was previously discovered using simple signal proc... | bayesian approach for detecting dynamically triggered very low-frequency earthquakes in the nankai subduction zone and application to the 2016 mw 5.9 off-kii peninsula earthquake, japan |
the time-reversal imaging method has become a standard technique for seismic source location using both acoustic and elastic wave equations. although there are many studies on the determination of the relevant parameter for visualization of the time-reversal method, little has been done so far to investigate the accura... | using the morris sensitivity analysis method to assess the importance of input variables on time-reversal imaging of seismic sources |
this study examines the biomimicry of wave propagation, a mode of locomotion in aquatic life for the use-case of morphing aircraft surfaces for boundary layer control. such motion is theorized to inject momentum into the flow on the upper surface of airfoils, and as a consequence, creates a forcible pressure gradient t... | flow control and separation delay in morphing wing aircraft using traveling wave actuation |
this research communication aims to obtain the periodic wave solutions of the double dispersive equation of the wave propagation in a nonlinear elastic inhomogeneous murnaghan's rod by using the f -expansion technique. this method first converts the partial differential equation into an ordinary differential equation u... | jacobi elliptic function solutions of the double dispersive equation in the murnaghan's rod |
earthquake early warning (eew) systems aim to provide advance warning of impending ground shaking, and the technique used for real-time prediction of shaking is a crucial element of eew systems. many eew systems are designed to predict the strength of seismic ground motions (peak ground acceleration, peak ground veloci... | real-time prediction of impending ground shaking: review of wavefield-based (ground-motion-based) method for earthquake early warning |
ultrasonic transmission is sensitive to the spatial variation in mechanical properties of materials due to the presence of cracks/fractures. wave propagation through fractured media introduces changes in the frequency content, travel time and transmission coefficient of the wave. a workflow based on physics-informed un... | visualization of hydraulic fracture using physics-informed clustering to process ultrasonic shear waves |
in this work, a proper orthogonal decomposition (pod) based reduced-order model (rom) is developed to solve gray, flux-limited thermal radiation diffusion. we focus on the variable opacity radiation penetration benchmark posed by olson, auer, and hall. the t-3 relationship for opacity in conjunction with high-temperatu... | proper orthogonal decomposition based reduced-order modeling of flux-limited gray thermal radiation |
the accurate simulation of wave propagation is a problem of longstanding interest. in this article, the focus is on higher-order accurate finite difference schemes for the wave equation in any number of spatial dimensions. in particular, two-step schemes (which operate over three time levels) are studied. a novel appro... | higher-order accurate two-step finite difference schemes for the many-dimensional wave equation |
continental rifting during the oligocene to mid-miocene caused the opening of the sea of japan and the separation between the japanese islands and the eurasian plate. the tectonic evolution in the sea of japan is important for understanding the evolution of back-arc regions in active convergent margins. here, we use da... | layered anisotropy within the crust and lithospheric mantle beneath the sea of japan |
magnonics is an emerging research area where magnons or spin waves are used as a medium of information processing. efficient manipulation/gating of magnons on-chip is crucial for realization of logic circuitry and device integration. here, we show a simple method for gating of the magnons in a magnetic wire based on th... | microwave assisted gating of spin wave propagation |
seismic time-lapse techniques are a valuable tool used to estimate the mobilization and distribution of stored co2 in depleted reservoirs. the success of these techniques depends on knowing the seismic properties of partially saturated rocks with accuracy. it is commonplace to use controlled laboratory-scale experiment... | modelling ultrasonic laboratory measurements of the saturation dependence of elastic modulus: new insights and implications for wave propagation mechanisms |
we present a technique to measure the young's modulus of a gelatin, using shear waves. gelatin is a commonly used material for analogue experiments in geophysics, investigating fluid-filled fractures like magmatic dikes, as well as fault slip. using polarized filters, the deviatoric stresses in a block of gelatin becom... | shear wave measurements of a gelatin's young's modulus |
terahertz scanning-probe near-field optical microscope (thz-snom), operating in transmission mode and relying on a flexible sapphire fiber, was developed. for this aim, a 300-μm-diameter step-index sapphire optical fiber with flat ends, high surface, and volume quality was fabricated using the edge-defined film-fed gro... | terahertz transmission-mode scanning-probe near-field optical microscopy based on a flexible step-index sapphire fiber |
rock bolts ensure structural stability for tunnels and many other underground structures. the pre-load on a rock bolt plays an important role in the structural reinforcement and it is vital to monitor the pre-load status of rock bolts. in this paper, a rock bolt pre-load monitoring method based on the piezoceramic enab... | monitoring of pre-load on rock bolt using piezoceramic-transducer enabled time reversal method |
spin wave propagation in perovskite la0.33 sr0.67 mno3 films epitaxially grown on a srtio3 substrate of (001) orientation was investigated using an all electrical spin wave spectroscopy technique. the spin wave nonreciprocity in amplitude, resonance frequency, and group velocity of the transmission spectra were observe... | surface anisotropy induced spin wave nonreciprocity in epitaxial la0.33 sr0.67 mno3 film on srtio3 substrate |
we present a critical analysis of the observations and interpretation of vlf subionospheric measurements related to the main nepal gorkha earthquake which occurred on 25 april 2015 (mw7.8) and its major aftershock on 12 may 2015 (mw7.3). the vlf narrowband signal used is from north west cape (nwc) (19.8 khz) vlf transm... | the 25 april 2015 nepal earthquake: investigation of precursor in vlf subionospheric signal |
context. searches for magnetic fields in white dwarfs have clarified both the frequency of occurrence and the global structure of the fields found down to field strengths of the order of 500 kg. below this level, the situation is still very unclear.aims: we are engaged in a project to find and study the weakest magneti... | a novel and sensitive method for measuring very weak magnetic fields of da white dwarfs. a search for a magnetic field at the 250 g level in 40 eridani b |
elastic moduli and velocities of tight sandstones are strongly influenced by rock-frame heterogeneity, pore microstructure and fluid in addition to pressure and probing-wave frequency. the effects of pressure and frequency on the elastic moduli and velocities are different from those of conventional sandstones with hig... | coupled effects of pressure and frequency on velocities of tight sandstones saturated with fluids: measurements and rock physics modelling |
solution‑processed semiconductors such as conjugated polymers have great potential in large‑area electronics. while extremely appealing due to their low‑temperature and high‑throughput deposition methods, their integration in high‑performance circuits has been difficult. an important remaining challenge is the achievem... | trap healing for high‑performance low‑voltage polymer transistors and solution‑based analog amplifiers on foil |
in the field of domain decomposition (dd), optimized schwarz method (osm) appears to be one of the prominent techniques to solve large scale time-harmonic wave propagation problems. it is based on appropriate transmission conditions using carefully designed impedance operators to exchange information between sub-domain... | robust treatment of cross points in optimized schwarz methods |
in nonlinear ultrasonic testing, the quadratic and more recently cubic nonlinearity parameters are frequently measured as a quantitative indicator of damaged material state. application of higher-order harmonics can improve the sensitivity of detection and monitoring for damages and microstructures due to their higher ... | application of odd harmonic resonances of a single crystal to generation and reception of superharmonic waves for sensitive monitoring of heat-treated materials |
wave velocity measurements were performed on fontainebleau sand samples used as a martian regolith simulant to investigate the elastic properties of the surface material at the insight landing site on mars (elysium planitia). loose samples (density 1.4 mg/m3, density index 6%) were prepared by using the pluviation meth... | wave velocities and poisson ratio in a loose sandy martian regolith simulant under low stresses: 1. laboratory investigation |
the space-air-ground-sea integrated network (sagsin) plays an important role in offering global coverage. to improve the efficient utilization of spectral and hardware resources in the sagsin, integrated sensing and communications (isac) has drawn extensive attention. most existing isac works focus on terrestrial netwo... | beam squint-aware integrated sensing and communications for hybrid massive mimo leo satellite systems |
low permeability, high retention capacity and self-sealing ability are advantageous characteristics that are attributed to argillaceous rocks. in contrast, other properties of clay, such as internal heterogeneities, strong attenuation and anisotropic behaviour, pose major challenges for underground exploration techniqu... | performance of high-resolution impact and vibration sources for underground seismic exploration of clay formations at the scale of a rock laboratory |
supersonic rockets generate low-frequency acoustic waves, that is, infrasound, during the launch and re-entry. infrasound is routinely observed at infrasound arrays from the international monitoring system, in place for the verification of the comprehensive nuclear-test-ban treaty. association and source identification... | infrasound from the 2009 and 2017 dprk rocket launches |
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