abstract stringlengths 3 192k | title stringlengths 4 857 |
|---|---|
solar images observed in different channels with different instruments are crucial to the study of solar activity. however, the images have different fields of view, causing them to be misaligned. it is essential to accurately register the images for studying solar activity from multiple perspectives. image registratio... | high-precision multichannel solar image registration using image intensity |
synthetic dispersion curves are here computed in the frame of an ambient-vibration full-wavefield model, which relies on the description of both ambient-vibration ground displacement and its sources as stochastic fields defined on the earth's surface, stationary in time and homogeneous in space. in this model, previous... | power spectral density function and spatial autocorrelation of the ambient vibration full-wavefield generated by a distribution of spatially correlated surface sources |
all lightning strokes generate electromagnetic pulses -atmospherics- which can travel over distances of thousands of kilometers. night-side atmospherics show typical frequency dispersion signatures caused by sub-ionospheric propagation. their analysis can be used to determine the distance to the source lightning, and t... | unusual electromagnetic signatures of european north atlantic winter thunderstorms |
this paper describes a concept for vibration-mitigation techniques with the potential to reduce the ground vibration amplitudes by applying an additional vibration source. the idea is presented through the case of an impact load. equations of motion for the transversally isotropic ground model with absorbing boundary c... | a proposal for vibration isolation of structures by using a wave generator |
we report in this work the determination of the solar radius from observations by the helioseismic and magnetic imager (hmi) and the atmospheric imaging assembly (aia) instruments on board the solar dynamics observatory during the 2012 june venus transit of the sun. two different methods were utilized to determine the ... | measuring the solar radius from space during the 2012 venus transit |
by means of muon spin relaxation measurements we unraveled the temperature spin dynamics in monodisperse maghemite spherical nanoparticles with different surface to volume ratio, in two samples with a full core (diameter d ∼4 and d ∼5 nm ) and one with a hollow core (external diameter d ∼7.4 nm ). the behavior of the m... | low-temperature anomalies in muon spin relaxation of solid and hollow γ -f e2o3 nanoparticles: a pathway to detect unusual local spin dynamics |
we propose a surface-wave dispersion retrieval method and synthesis technique that applies to bianisotropic metasurfaces that are embedded in symmetric or asymmetric environments. specifically, we use general zero-thickness sheet transition conditions to relate the propagation constants of surface-wave modes to the bia... | surface-wave dispersion retrieval method and synthesis technique for bianisotropic metasurfaces |
seismic hazard estimation relies classically on data-based ground motion prediction equations (gmpes) giving the expected motion level as a function of several parameters characterizing the source and the sites of interest. however, records of moderate to large earthquakes at short distances from the faults are still r... | near-fault broadband ground motion simulations using empirical green's functions: application to the upper rhine graben (france-germany) case study |
in this paper, we present a magnetostrictive phased array sensor (mpas) with a polycrystalline nickel patch of a circular comb shape in order for the use of the ultrasonic guided lamb wave inspection technique. the mpas was comprised of two main components of the surface-mounted nickel patch and a mobile magnetic circu... | enhancement of directional sensitivity of magnetostrictive phased array sensor using a circular comb-shaped nickel patch |
the use of schlieren photography has been essential in unravelling the complex nature of high-speed combustion phenomena, but its line-of-sight integration makes it difficult to decisively determine the nature of multi-dimensional combustion wave propagation. conventional schlieren alone makes it impossible to determin... | simultaneous schlieren photography and soot foil in the study of detonation phenomena |
long-time instabilities have been observed in various scenarios of numerical simulation for seismic wave propagation. they appear as slowly magnifying spurious oscillations in the seismograms at the late stage of the simulation. their magnifying speed is typically much slower than the magnifying speed observed when the... | using time filtering to control the long-time instability in seismic wave simulation |
neoclassical tearing modes are macroscopic (l ∼ 1 m) instabilities in magnetic fusion experiments; if unchecked, these modes degrade plasma performance and may catastrophically destroy plasma confinement by inducing a disruption. fortunately, the use of properly tuned and directed radiofrequency waves (λ ∼ 1 mm) can el... | coupling extended magnetohydrodynamic fluid codes with radiofrequency ray tracing codes for fusion modeling |
reconfigurable intelligent surfaces (ris) is considered as a revolutionary technique to improve the wireless system performance by reconfiguring the radio wave propagation environment artificially. motivated by the potential of ris in vehicular networks, we analyze the secrecy outage performance of ris-aided vehicular ... | secure vehicular communications through reconfigurable intelligent surfaces |
the nature of multipolar order and hyperfine-enhanced (he) 141pr nuclear spin dynamics in prv2al20 was investigated using the muon spin relaxation technique. no explicit sign of time-reversal symmetry breaking was found below the multipolar order temperature tq∼0.6 k in a zero applied field as anticipated on the basis ... | perturbation on hyperfine-enhanced 141pr nuclear spin dynamics associated with antiferroquadrupolar order in prv2al20 |
to estimate coastal risk it is necessary to integrate the joint probability density function, including extremes, of the sea condition variables over a function that defines the consequences, typically economic damage. the use of monte carlo methods is common practice to undertake this integration; however, it can intr... | the use of wave propagation and reduced complexity inundation models and metamodels for coastal flood risk assessment |
recent developments of distributed acoustic sensing (das) techniques and rotational seismometers enable us to record strain and rotational seismograms. this prompts us to adapt the methods used for traditional translational seismograms to strain and rotational seismograms. recently, we extended the formulation of the s... | connection between the cross correlation and the green's function: strain and rotation of surface waves |
this article scrutinizes the efficacy of analytical mathematical schemes, improved simple equation and exp$(-\text{ψ}(ξ))$-expansion techniques for solving the well-known nonlinear partial differential equations. a longitudinal wave model is used for the description of the dispersion in the circular rod grounded via tr... | analytical mathematical schemes: circular rod grounded via transverse poisson's effect and extensive wave propagation on the surface of water |
we discuss the ultrasonic wave propagation characteristics in an isotropic elastic solid due to the radial mode excitation of a piezoelectric disc actuator bonded to its surface. finite element simulations using coupled electromechanical modeling is employed to investigate the wave propagation behavior. we find that th... | ultrasonic waves from radial mode excitation of a piezoelectric disc on the surface of an elastic solid |
the propagation characteristics of f-(flexural) wave and the reflection from vertical cracks in pipe-piles subjected to an eccentric vertical excitation were numerically investigated using elastodynamic finite integration technique (efit). the accuracy of the self-written code was validated by comparing computed result... | propagation characteristics of flexural wave and the reflection from vertical cracks during pipe-pile integrity testing |
the site-specific earthquake ground motion parameters were presented for the southeastern part of muscat governorate, including amplification factor at different periods and the values of pga and spectral accelerations at the surface. the study starts with assessment of the seismic hazard at bedrock level using the pro... | site-specific earthquake ground motion parameters at the southeastern part of muscat, sultanate of oman |
the nonlinear propagation of coupled alfvén and ion-acoustic waves is investigated in homogeneous, magnetized and collisionless electron-ion plasma. the ion parallel motion is included in the model so that ion-acoustic wave couples with alfvén wave in plasmas. in linear limit, the dispersion relation of coupled alfvén ... | nonlinear periodic coupled alfvén and ion-acoustic wave structures in plasmas |
radial heat transfer in viscous pipe flow is controlled by thermal conduction which leads to a wide radial temperature distribution and slow heating of the core region of the flow. this is highly undesirable in many industrial processes as it results in a grossly uneven distribution of fluid heat treatment. the use of ... | an improved vibration technique for enhancing temperature uniformity and heat transfer in viscous fluid flow |
current clinical tools provide critical information about ocular health such as intraocular pressure (iop). however, they lack the ability to quantify tissue material properties, which are potent markers for ocular tissue health and integrity. we describe a single instrument to measure the eye-globe iop, quantify corne... | applanation optical coherence elastography: noncontact measurement of intraocular pressure, corneal biomechanical properties, and corneal geometry with a single instrument |
for systems that require complete metallic enclosures (e.g., containment buildings for nuclear reactors), it is impossible to access interior sensors and equipment using standard electromagnetic techniques. a viable way to communicate and supply power through metallic barriers is the use of elastic waves and ultrasonic... | machined phononic crystals to block high-order lamb waves and crosstalk in through-metal ultrasonic communication systems |
seismic azimuthal anisotropy characterized by shear wave splitting analyses using teleseismic xks phases (including sks, skks, and pks) is widely employed to constrain the deformation field in the earth's crust and mantle. due to the near-vertical incidence of the xks arrivals, the resulting splitting parameters (fast ... | receiver function investigations of seismic anisotropy layering beneath southern california |
resonant metamaterials and phononic crystals are widely studied, with the aim of controlling and altering elastic wave propagation in solids. beams with varying stiffness along the length are an archetypal example of a phononic crystal for bending waves, since the resulting nontrivial dispersion relation can be modeled... | energy distribution and exchange between spatial harmonics in bending wave phononic crystals |
the paper presents the results of integrated ground penetrating radar (gpr) and ultrasonic testing (ut) measurements conducted on a historical floor in st. nicholas' church, gdańsk, poland. the described inspection was the first stage of the technical state assessment of the building. the aim of the study was the detec... | integrated application of gpr and ultrasonic testing in the diagnostics of a historical floor |
we investigate laser-induced acoustic wave propagation through smooth and roughened titanium-coated glass substrates. acoustic waves are generated in a controlled manner via the laser spallation technique. surface displacements are measured during stress wave loading by the alignment of a michelson-type interferometer.... | the effect of surface roughness on laser-induced stress wave propagation |
the numerical modeling of mechanical waves is currently a fundamental tool for the study and investigation of their propagation in media with heterogeneous physical properties and/or complex geometry, as, in these cases, analytical methods are usually not applicable. these techniques are used in geophysics (geophysical... | numerical modeling of mechanical wave propagation |
for skywave over-the-horizon radar, beamforming techniques are often used to suppress airspace radio frequency interference because the high-frequency band is shared by many devices. to address the problems that the traditional beamforming method is not capable of recognizing the electromagnetic environment and that it... | a cognitive beamforming method via range-doppler map features for skywave radar |
we have developed isee_wave (institute for space-earth environmental research, nagoya university - plasma wave analysis tool), an interactive plasma wave analysis tool for electric and magnetic field waveforms observed by the plasma wave experiment aboard the arase satellite. isee_wave provides an integrated wave analy... | isee_wave: interactive plasma wave analysis tool |
due to the relatively low ionization levels present in the d-region of the ionosphere (60-90 km), few reliable methods exist for estimating electron densities at this altitude. very low frequency (vlf, 3-30 khz) radio waves, unlike higher frequency waves used for similar remote sensing applications, are sensitive to th... | the estimation of d-region electron densities from trans-ionospheric very low frequency signals |
the f2-layer propagation factor m(3000)f2 is important to ionospheric studies owning to its use in high high frequency radio communication/ionospheric modeling. this study focused on reducing the shortcomings in the use of m(3000)f2 iri-model for obtaining hmf2, especially in the african equatorial region, by obtaining... | modelling m(3000)f2 at an african equatorial location for better iri-model prediction |
the ray-tracing technique under the high-frequency assumption has been widely used in seismic wave propagation and migration. however, the practical use of conventional ray tracing is limited in complicated media especially when seismic data are band limited. besides, the ray-tracing method also suffers from shadow zon... | band-limited beam propagator and its application to seismic migration |
measurement of the small filling levels in closed steel container systems is still a challenge. ultrasound, however, is a sensitive and non-invasive technique and is suitable for online monitoring. this study describes a new ultrasonic sensor system for sensing small filling levels using longitudinal and surface acoust... | combined longitudinal and surface acoustic wave analysis for determining small filling levels in curved steel containers |
consider the diffraction of an electromagnetic plane wave by a biperiodic structure where the wave propagation is governed by the three-dimensional maxwell equations. based on transparent boundary condition, the grating problem is formulated into a boundary value problem in a bounded domain. using a duality argument te... | an adaptive finite element dtn method for maxwell's equations in biperiodic structures |
hydraulic fracturing is a common stimulation technique in unconventional reservoirs to create fractures systems and allow hydrocarbon production. proppant (granular material) is normally injected during hydraulic fracturing to keep open the fracture network and enhance hydrocarbon production performance. proppant has a... | compliance estimation and multiscale seismic simulation of hydraulic fractures |
this paper presents a real-time signal processing and damage localization framework for ultrasonic guided wave based structural health monitoring of x-cor sandwich composites with a reference-free perspective. the high attenuation nature of x-cor composite significantly limits the ability to detect damage-induced refle... | multi-dimensional signal processing and mode tracking approach for guided wave based damage localization in x-cor sandwich composite |
gerald beresford (gb) whitham, frs, (13th december, 1927-26th january, 2014) was one of the leading applied mathematicians of the twentieth century whose work over forty years had a profound, formative impact on research on wave motion across a broad range of areas. many of the ideas and techniques he developed have no... | modulation theory, dispersive shock waves and gerald beresford whitham |
the volumetric characterization of delaminations necessarily precedes rigorous composite damage progression modeling. yet, inspection of composite structures for subsurface damage remains largely focused on detection, resulting in a capability gap. in response to this need, angle longitudinal wave ultrasound was employ... | volumetric characterization of delamination fields via angle longitudinal wave ultrasound |
laser ultrasonics is a technique where lasers are used for the generation and detection of ultrasound instead of conventional piezoelectric transducers. the technique is broadband, non-contact, and couplant free, suitable for large stand-off distances, inspection of components of complex geometries and hazardous enviro... | full matrix capture and the total focusing imaging algorithm using laser induced ultrasonic phased arrays |
we present a technique to construct a spectropolarimetrically accurate magnetohydrostatic model of a large-scale solar magnetic field concentration, mimicking a sunspot. using the constructed model we perform a simulation of acoustic wave propagation, conversion, and absorption in the solar interior and photosphere wit... | spectropolarimetrically accurate magnetohydrostatic sunspot model for forward modeling in helioseismology |
with the rapid development of short-pulse intense laser sources, studies of matter under extreme irradiation conditions enter further unexplored regimes. in addition, an application of x-ray free-electron lasers (xfels) delivering intense femtosecond x-ray pulses, allows to investigate sample evolution in ir pump - x-r... | femtosecond laser produced periodic plasma in a colloidal crystal probed by xfel radiation |
providing minimum quality-of-service (qos) in crowded wireless communications systems, with high user density, is challenging due to the network structure with limited transmit power budget and resource blocks. smart resource allocation methods, such as user scheduling, power allocation, and modulation and coding schem... | qos-aware user scheduling in crowded xl-mimo systems under non-stationary multi-state los/nlos channels |
amplitude-modulated (am) leaky-wave antenna (lwa), a concept following amplitude modulation technique from classical communications theory, is a promising structure that enables transforming traveling wave into the radiating wave. in this paper, we provide a different perspective based on the classical holographic theo... | holographic amplitude-modulated (am) leaky-wave antennas for near-field and far-field applications |
it has been well established that source-path-site effects have had an essential impact on the seismic analysis of major infrastructure over the past few decades, where the accurate and efficient modeling of seismic wave propagation can become a critical issue. in this study, a two-step approach combining the frequency... | a two-step approach combining fk with se for simulating ground motion due to point dislocation sources |
a new super-long-range wave propagation technique was implemented at different hf heating facilities. the hf waves radiated by a powerful heater were scattered into the ionospheric waveguide by the stimulated field aligned striations. this waveguide is formed in a valley region between the e- and f- layers of the ionos... | ionospheric nonlinear effects observed during very-long-distance hf propagation |
a combined technology of vortex beam technique and electron holography has been developed. a range about 10 times the diameter of the grating opening was irradiated and two-wave interference between a bragg diffraction wave as a vortex beam and a transmitted wave from and around a fork-shaped grating was recorded as a ... | electron holography for vortex beams |
the dynamic model about the anti-plane vibration of a contoured quartz plate with thickness changing continuously is established by ignoring the effect of small elastic constant c 56. the governing equation is solved using the power series expansion technique, and the trapped thickness shear modes caused by bulge thick... | the investigation of trapped thickness shear modes in a contoured at-cut quartz plate using the power series expansion technique |
a novel nonlocal model with one thermal relaxation time is presented to investigate the propagation of waves in a thermoelastic semi-infinite medium. we used eringen's theory of the nonlocal continuum to develop these models. analytical solutions in all physical quantities are provided by using laplace transforms and e... | analytical solutions of nonlocal thermoelastic interaction on semi-infinite mediums induced by ramp-type heating |
this paper is devoted to the thermal shock analysis for viscoelastic materials under transient heating loads. the governing coupled equations with time-delay parameter and nonlocal scale parameter are derived based on the generalized thermo-viscoelasticity theory. the problem of a thin plate composed of viscoelastic ma... | shock-induced thermal wave propagation and response analysis of a viscoelastic thin plate under transient heating loads |
a simple experimental technique, based on pressure transducers, capable of measuring the stress wave that propagates along the solid phase of a granular column after being hit head-on by a plane shock wave is presented. the technique is based on installing couples of gauges at different cross-sections along the granula... | experimental investigation of the stress wave propagation inside a granular column impacted by a shock wave |
in this study, surface seismic measurements in the field at a rock outcrop (peridotite) and laboratory high frequency seismic measurements of spherical rock samples were compared. both the field and the laboratory velocities of p- and s- waves were determined using pulse-transmission technique. special conditions at th... | comparison of laboratory and field measurements of p and s wave velocities of a peridotite rock |
multioffset phase analysis (mopa) is a fairly recent technique for evaluating seismic surface wave dispersion and estimating the presence of lateral variations. the main limitation of mopa is that it is based on the assumption of one predominant mode, usually the fundamental mode, in the wave propagation. however, mopa... | multimode multioffset phase analysis of surface waves, a new approach to extend mopa to higher modes |
the proliferation of nuclear tests is a problem that threatens the safety and health of everybody. in order to tackle this problem, the un is promoting the comprehensive nuclear-test-ban treaty (ctbt), which includes protocols for monitoring and on-site inspections (osi). the purpose of osi is to verify if a nuclear te... | theoretical signature of a cavern created by an underground nuclear explosion in 2-d exploration seismic data |
accurate characterisation of dynamic behaviour of ceramics requires the reliable split-hopkinson pressure bar (shpb) technique and the condition of uniaxial homogeneous specimen deformation. in this study, an experimentally validated 3d finite element model of the full scale shpb experiment was developed to quantitativ... | characterisation of dynamic behaviour of alumina ceramics: evaluation of stress uniformity |
the influence of the dust-ion collision effect on the propagation of ion-acoustic waves (iaws) in a collisional magnetized dusty plasma containing positive ions, dust grains with a negative charge and the electrons that follow combined kappa-cairns distribution is observed. employing reductive perturbation technique (r... | studies on the effect of dust-ion collision on dust-ion acoustic solitary waves in a magnetized dusty plasma in the framework of damped kp equation and modified damped kp equation |
studying seismic wave propagation through complex media is crucial to numerous aspects of geophysics and engineering including seismic hazard assessment. in particular, small-scale structure such as sedimentary basins and their edges can have significant effects on high-frequency earthquake ground motion, which is the ... | seismic wave simulation using a 3d printed model of the los angeles basin |
this book presents the theory of waves propagation in a fluid-saturated porous medium (a biot medium) and its application in applied geophysics. in particular, a derivation of absorbing boundary conditions in viscoelastic and poroelastic media is presented, which later is employed in the applications. the partial diffe... | numerical simulation in applied geophysics |
the attributes of acoustic envelope waves in a collisionless dust ion unmagnetized plasmas model composed of cold ions, superthermal electrons and positive-negative dust grains have been studied. using the derivative expansion technique in a strong dispersive medium, the system model is reduced to a nonlinearly form of... | wave propagation in strongly dispersive superthermal dusty plasma |
lateral spatial variations of weak portions at the plate boundary in subduction zones have been estimated primarily by the distribution of slow earthquakes mainly occurring around seismogenic zones. however, the detailed depth profile of weak faults remains elusive. here, we deployed six ocean bottom seismometers in th... | weak faults at megathrust plate boundary respond to tidal stress |
a porous core photonic crystal fiber (pcf) for transmitting terahertz waves is reported and characterized using finite element method. it is shown that by enveloping an octagonal core consisting of only circular air holes in a hexagonal cladding, it is possible to attain low effective material loss that is 73.8% lower ... | theoretical assessment of a porous core photonic crystal fiber for terahertz wave propagation |
in the present study non-destructive testing (ndt) methods involving ultrasonic and sonic wave propagation in the solid matter were applied in order to detect and investigate the modifications induced by the seismic load on reinforced concrete (rc) buildings. in particular, the aim of this experimental work was to deli... | a non-destructive testing methodology for damage assessment of reinforced concrete buildings after seismic events |
visualizing information inside objects is an ever-lasting need to bridge the world from physics, chemistry, biology to computation. among all tomographic techniques, terahertz (thz) computational imaging has demonstrated its unique sensing features to digitalize multi-dimensional object information in a non-destructive... | physics-guided terahertz computational imaging |
we study the average energy - or particle - density of waves inside disordered 1d multiply-scattering media. we extend the transfer-matrix technique that was used in the past for the calculation of the intensity beyond the sample to study the intensity in the interior of the sample by considering the transfer matrices ... | connection between wave transport through disordered 1d waveguides and energy density inside the sample: a maximum-entropy approach |
a one-dimensional problem of wave propagation in phononic materials is solved under the reduced micromorphic model introduced recently. an efficient technique is used for the solution, based on one-sided fourier transform. this allows obtaining an exact solution in closed form, which can be utilized to check approximat... | wave propagation in phononic materials based on the reduced micromorphic model by one-sided fourier transform |
ultrasonic properties of coarse-grained austenite are critical to the quantitative nondestructive testing and evaluation of cast austenitic stainless steel (cass). however, the orientation-dependent information is quite difficult to acquire from polycrystalline materials. here a grain-scale measurement technique was de... | gain-scale ultrasonic properties measurement of cast austenitic stainless steel |
scattering of plane longitudinal monochromatic waves from a heterogeneous inclusion of arbitrary shape in an infinite poroelastic medium is considered. wave propagation in the medium is described by biot's equations of poroelasticity. the scattering problem is formulated in terms of the volume integral equations for di... | scattering of plane monochromatic waves from a heterogeneous inclusion of arbitrary shape in a poroelastic medium: an efficient numerical solution |
acoustic emission (ae) is a monitoring technique that has proven its suitability in and outside of the laboratory in characterizing the structural condition of materials. in composites for construction and repair, several breakthroughs have been recently noted involving mainly fracture mode evaluation based on the ae w... | dimension effects on the acoustic behavior of trc plates |
the impact induced dynamic response and the failure behavior of aircraft structures continues to be a critical aeronautical engineering challenge in order to improve the passenger survivability after aircraft. it is the objective of this special issue to provide a review of the work at the university of naples federico... | impact induced dynamic response and failure behavior of aircraft structures |
this study aims to present a procedure for predicting the bearing capacity of a soil slope under seismic loading. the emphasis is on the variations of soil strength parameters. in order to account for soil profile with varying friction angles in the generation of a potential collapse mechanism, the discretization techn... | seismic bearing capacity of non-uniform soil slopes using discretization-based kinematic analysis considering rayleigh waves |
vegetation is one of the most important components of nature-based coastal protection due to its ability to dissipate wave energy. to quantify the wave attenuation by vegetation, traditional analytical models assume rigid vegetation and use bulk drag coefficient (cd) or effective blade length (le) techniques to conside... | wave attenuation by flexible vegetation (and suspended kelp) with blade motion: analytical solutions |
we describe a new spectrophotometer for the birmingham solar oscillations network (bison), based on a next generation observation platform, bison:ng, a significantly miniaturized system making use of inexpensive consumer-grade hardware and off-the-shelf components, where possible. we show through system modelling and s... | the next generation birmingham solar oscillations network (bison) spectrophotometer: a new miniaturized instrument for helioseismology |
the advent of free-electron lasers opens new routes for experimental high-pressure physics, which allows studying dynamics of condensed matter with femtosecond resolution. a rapid compression, that can be caused by laser-induced shock impact, leads to the cascade of high-pressure phase transitions. despite many decades... | dynamics of ultrafast phase transitions in mgf2 triggered by laser-induced thz coherent phonons |
we demonstrate the use of machine learning algorithms in combination with segmentation techniques in order to distinguish coronal holes and filaments in solar extreme ultraviolet (euv) images recorded by the atmospheric imaging assembly onboard the solar dynamics observatory. we used the spatial possibilistic clusterin... | "chapter 15 - coronal holes detection using supervised classification |
rayleigh type surface wave propagation in the irregular bottom of ocean model which is the interface of homogeneous liquid layer over laying an irregular boundary of homogeneous orthotropic half space under initial stresses has been discussed in this paper. three different dispersion equations are obtained in the form ... | study of rayleigh type surface wave in the initial stressed irregular bottom of ocean due to point source |
the myocardium is known to be an anisotropic medium where the muscle fiber orientation changes through the thickness of the wall. shear wave elastography methods use propagating waves which are measured by ultrasound or magnetic resonance imaging (mri) techniques to characterize the mechanical properties of various tis... | investigation of the effects of myocardial anisotropy for shear wave elastography using impulsive force and harmonic vibration |
our long-term goal is to develop an ultrasonic method to characterize the thickness, stiffness and porosity of the cortical shell of the femoral neck, which could enhance hip fracture risk prediction. to this purpose, we proposed to adapt a technique based on the measurement of guided waves. we previously evidenced the... | a method for the measurement of dispersion curves of circumferential guided waves radiating from curved shells: experimental validation and application to a femoral neck mimicking phantom |
in earthquake early warning systems, real-time shake prediction through wave propagation simulation is a promising approach. compared with traditional methods, it does not suffer from the inaccurate estimation of source parameters. for computation efficiency, wave direction is assumed to propagate on the 2-d surface of... | real-time 3-d space numerical shake prediction for earthquake early warning |
in this paper, we present an efficient spectral-element method (sem) for solving general two-dimensional helmholtz equations in anisotropic media, with particular applications in accurate simulation of polygonal invisibility cloaks, concentrators and circular rotators arisen from the field of transformation electromagn... | seamless integration of global dirichlet-to-neumann boundary condition and spectral elements for transformation electromagnetics |
non-overlapping schwarz methods with generalized robin transmission conditions were originally introduced by b. després for time-harmonic wave propagation problems and have largely developed over the past thirty years. the aim of the paper is to provide both a review of the available formulations and methods as well as... | a unified theory of non-overlapping robin-schwarz methods -- continuous and discrete, including cross points |
shear wave absolute vibro-elastography (s-wave) is an imaging technique that generates steady-state shear waves inside the tissue using multi-frequency excitation from an external vibration source. in this work, plane wave imaging is introduced to reduce total acquisition time while retaining the benefit of 3d formulat... | ultrafast ultrasound imaging for 3d shear wave absolute vibro-elastography |
in the present paper, two distinct multiferroic composites are taken into account, i.e., pe (piezoelectric)/pm (piezomagnetic). an analytical technique is applied to study the shear horizontal (sh) wave propagation in a layered pre-stressed rotating cylindrical tube structure consisting of a pe material layer which is ... | interfacial imperfection study in pres-stressed rotating multiferroic cylindrical tube with wave vibration analytical approach |
a pickering emulsion is an emulsion stabilized by solid particles accumulated at the surface of droplets. it is also possible to create a stable pickering emulsion stabilized by ferromagnetic iron oxide nanoparticles to make it susceptible to magnetic fields. this type of emulsion has received great research interest i... | propagation of ultrasonic wave in magnetic pickering emulsion under dc magnetic field |
sound transmission through infinite planar multilayered structures characterized by in-plane periodicity is accurately and efficiently predicted by exploiting free wave propagation and bloch modes. a through-thickness transfer matrix is derived for each layer by manipulating the dynamic stiffness matrix related to a fi... | generalized transfer matrix method for periodic planar media |
high-speed three-dimensional digital image correlation (3d-dic) technique was utilised to examine the ejection velocity characteristics of rock fragment in dynamic compression tests. the fragment velocity components of fragment were extracted from velocity fields distributed within the fragment area. by identifying the... | measurement of ejection velocity of rock fragments under dynamic compression and insight into energy partitioning |
the tilted tilted transversely isotropic (tti) media, a kind of anisotropic medium, widely exists within the earth. for faster calculation of travel times in the tti anisotropic media, we modified a minimum traveltime tree algorithm with high efficiency by dynamical modification of the secondary wave propagation region... | fast and accurate calculation of seismic wave travel time in 3d tti media |
the effect of ion-ion collision on the dynamics of nonlinear magnetosonic wave in a magnetized pair-ion plasma consisting of positive and negative ions has been studied. the external magnetic field is situated perpendicular to the wave propagation. two fluid model is used to describe the dynamics of positive and negati... | solitary and shock wave in magnetized collisional pair-ion plasmas |
a dense seismic array, composed of over 5000 stations with an average spacing close to 120 m was deployed in long beach, ca, by nodalseismic and signal hill petroleum as part of a survey associated with the long beach oilfield. among many interesting wave propagation effects that have been reported by others, we observ... | separating the scattered wavefield from teleseismic p using curvelets on the long beach array dataset |
nanosecond laser pulse-induced melting thresholds in refractory (nb, mo, ta and w) metals are measured using detected laser-generated acoustic shear waves. obtained melting threshold values were found to be scaled with corresponding melting point temperatures of investigated materials displaying dissimilar shearing beh... | examination of nanosecond laser melting thresholds in refractory metals by shear wave acoustics |
laser ultrasonic scanning, especially full-field wave propagation imaging, is attractive for damage visualization thanks to its noncontact nature, sensitivity to local damage, and high spatial resolution. however, its practicality is limited because scanning at a high spatial resolution demands a prohibitively long sca... | accelerated damage visualization using binary search with fixed pitch-catch distance laser ultrasonic scanning |
optical measurements were carried out in planar two-dimensional open shallow cavities in order to determine how the flow field inside the cavity changes if the length-to-depth ratio of the cavity and the conditions of the boundary layer at the cavity leading edge are varied. the main challenge in this configuration, na... | visualization of wave propagation within a supersonic two-dimensional cavity by digital streak schlieren |
the microscopic particle-in-cell (micpic) method was developed to model classical light-matter interaction in strongly-coupled plasma systems. it effectively overcomes the limitations of the particle-in-cell and molecular dynamics techniques by combining them into a single, unified framework to solve for both electroma... | massively parallel microscopic particle-in-cell |
for safe construction practise, it is important to monitor the hardening process of concrete during the construction stage itself. moreover, with the increasing use of supplementary cement-based materials (scm) in concrete construction which adversely alters (significantly delays) the setting and strength gain in concr... | monitoring the mechanical properties of flyash incorporated cement composite using complimentary passive-active wave propagation techniques |
this work aims at presenting a new numerical solution to a nonlinear, one-dimensional problem of heat wave propagation in a thick slab of a rigid thermal conductor. the model predicts dependence of second sound velocity on temperature and heat flux. for this, an unconditionally stable numerical scheme is constructed us... | numerical solution to a one-dimensional nonlinear problem of heat wave propagation in a rigid thermal conducting slab |
to clarify the characteristics of high-frequency (> 1 hz) s and s-coda waves at ocean-bottom seismometers (obss), we analyzed seismograms observed at permanent obss and inland broadband seismometers around the kii peninsula in southwest japan along the nankai trough. the coda amplitudes (both horizontal and vertical... | high-frequency s and s-coda waves at ocean-bottom seismometers |
in toroidal plasmas, electron bernstein (eb) waves mode-converted from x waves at the upper hybrid resonance (uhr) layer propagate toward the higher field side and are cyclotron-damped away at doppler shifted frequency before arriving at the electron cyclotron resonance (ecr) layer. resulting power deposition profile d... | mapping of power deposition zone of electron bernstein waves externally excited in tokamak plasmas |
based on conformal construction of physical model in a three-dimensional cartesian grid, an integral-based conformal convolutional perfectly matched layer (cpml) is given for solving the truncation problem of the open port when the enlarged cell technique conformal finite-difference time-domain (ect-cfdtd) method is us... | uniform stable conformal convolutional perfectly matched layer for enlarged cell technique conformal finite-difference time-domain method |
two‑photon (2p) optogenetic stimulation is currently the only method for precise, fast, and non‑invasive cellular excitation deep inside brain tissue; it is typically combined with holographic wavefront‑shaping techniques to generate distributed light patterns and target them to multiple specific cells in the brain. du... | real‑time in situ holographic optogenetics confocally unraveled sculpting microscopy |
vulnerable plaques are the major cause of cardiovascular disease, but they are difficult to detect with conventional intravascular imaging techniques. techniques are needed to identify plaque vulnerability based on the presence of lipids in plaque. thermal strain imaging (tsi) is an imaging technique based on ultrasoun... | photothermal strain imaging |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.