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recent direct measurements of the thermal conductivity of metals at combined high pressure and high temperature conditions have opened a new window into earth's deep heat transport, with implications for the operating conditions of the geodynamo, the age of the inner core, and earth's dynamic history. measurements of h... | direct thermal conductivity measurements on metals at high pressure and temperature: from the usual to the unusual |
while there has been near-continuous observation of the sun's surface magnetic field over the past few decades, there remains little insight concerning the configuration of the subsurface field. this work presents a simple helioseismic technique to estimate the orientation of the subsurface horizontal magnetic field as... | travel time anisotropy due to subsurface magnetic fields |
thermal transport properties of warm dense matter affect the evolution of many systems, ranging from geodynamo in the earth's core, to hydrodynamic instability growth in inertial confinement fusion (icf) capsules. we report thermal conductivity measurements of ch and be in the warm dense matter regime using x-ray diffe... | thermal transport study of warm dense ch and be by refraction-enhanced x-ray radiography with a deep neural network analysis |
the purpose of the new laboratory is to interrelate experimental studies of laboratory plasma in two research facilities, one at iap ras (nizhny novgorod) and the other at the nearby sura ionospheric heater, as well as to incorporate analysis of data from existing ionospheric heating facilities (haarp, eiscat, and arec... | new collaboration for studying interaction of waves and particles in the near-earth plasma: active experiment, laboratory modeling, and numerical simulation |
compact intracloud discharges (cids) persist to date as one of the most mysterious lightning manifestations. cids are known to be the strongest natural sources of radio-frequency radiation on earth. at vhf frequencies, approximately above 30 mhz, their emitted power is ten times stronger than that of other lightning pr... | elve doublets: the ionospheric fingerprints of compact intracloud discharges |
active-source 3d seismic migration and migration velocity analysis (mva) are robust and highly used methods for imaging earth structure. one class of migration methods uses extended images constructed by incorporating spatial and/or temporal wavefield correlation lags to the imaging conditions. these extended images al... | the utility of the extended images in ambient seismic wavefield migration |
in this study, utilizing depth-sensitivity of interferometric waveforms recorded by co-located hi-net and kik-net sensors, we separate the responsible depth of seismic velocity change associated with the m6.3 earthquake occurred on november 22, 2014, in central japan. the hi-net station n.mkgh is located about 20 km no... | depth-dependence of time-lapse seismic velocity change detected by a joint interferometric analysis of vertical array data |
we have collected three-component data from 122 korean accelerometer stations for the month of december in 2014. we apply similar techniques described by zha et al. (2013) to retrieve accurate station orientation angles, in order to rotate the horizontal component data into the radial and transverse frame of reference,... | application of the energy reassignment method to measure accurate rayleigh and love wave group velocities from ambient seismic noise cross-correlations |
one of the challenges in wide-band multimode guided wave testing is the decomposition of multimodal response signal into individual components. in this study the post-processing procedure based on plate wave mode orthogonality is proposed to extract individual waveforms at a plate edge from multimodal signals [1]. to o... | wave mode extraction from multimodal guided wave signal in a plate |
a practical method is proposed for determining the 3d wave-vector of quasi-neutral plasma waves using magnetic field and electric current density measurements made by a single spacecraft. this wave-vector knowledge can then be used to remove the space-time ambiguity produced by frequency doppler shift associated with s... | method for determining 3d wave-vector using measurements from only a single spacecraft |
deep ocean pressure sensors have proven very effective to quantify tsunami waves in real-time. yet, the cost of these sensors and maintenance strongly limit the extensive deployment of dense networks. thus a complete observation of the tsunami wave-field is not possible so far. in the last decade, imprints of moderate ... | contribution of ionospheric monitoring to tsunami warning: results from a benchmark exercise |
the canadian face of the resolute bay incoherent scatter radar (risr-c) began operations in 2015 and since then has been making highly detailed measurements of the polar ionosphere. the operations of risr-c are often complemented by measurements from the co-located northward facing risr-n radar which is operated by sri... | measurement of polar cap ionospheric velocities using the risr-c and superdarn radars |
we present a semianalytical numerical method to simulate sh-wave propagation in heterogeneous multiple layers with smooth property variations. wave propagation in such piecewise heterogeneous media will dominate the reflection and transmission at interfaces, whereas the scattered waves by volume heterogeneities inside ... | seismogram synthesis for multilayered heterogeneous media with irregular interfaces by the global generalized reflection-transmission matrices method |
a nonlinear boussinesq equation under fractal fractional caputo's derivative is studied. the general series solution is calculated using the double laplace transform with decomposition. the convergence and stability analyses of the model are investigated under caputo's fractal fractional derivative. for the numerical i... | theoretical and numerical analysis of nonlinear boussinesq equation under fractal fractional derivative |
most numerical approaches to solving the poroelastic wave equations are carried out in the time domain which involves a convolution associated with a frequency-dependent dynamic permeability. the problem of "stiff equations" arises due to the existence of the biot slow p-wave. under a low-frequency approximation the no... | seismic wave modelling in 2d poroelastic media using the second order frequency-domain finite difference method |
multistable mechanical metamaterials have recently provided unique platforms with wave guidance and wave steering capabilities. arrays of symmetric/asymmetric bistable elements, such as elastically/plastically deformed arches, can be patterned to control the signal transmission and to passively achieve nonreciprocal wa... | transition waves in multistable mechanical metamaterials under periodic excitation |
zinc oxide (zno) thin films have been grown by radio frequency sputtering technique on fused silica substrates. optical and morphological characteristics of as-grown zno samples were measured by various techniques; an x-ray diffraction spectrum showed that the films exhibited hexagonal wurtzite structure and were c-axi... | uv sensor based on surface acoustic waves in zno/fused silica |
a major part of the path of the annular solar eclipse of may 20, 2012 (magnitude 0.9439) was over southern japan. the d-region ionospheric changes associated with that eclipse, led to several degree of observable perturbations of sub-ionospheric very low frequency (vlf) radio signal. the university of electro-communica... | determination of spatio-temporal characteristics of d-region electron density during annular solar eclipse from vlf network observations |
the economic attractiveness of 5g networks influences the speed of their worldwide deployment drastically, putting the deployment process ahead of environmental studies. the analysis of 5g network parameters which affect the evaluation of electromagnetic ecology was carried out. it has shown the difference between 5g a... | features of electromagnetic situation estimation near the 5g base station antennas |
ranging measurements in the deep space network (dsn) have been contributing to spacecraft navigation and radio science investigations for more than a half century. the current ranging system, which uses a single frequency link (x-band), provides accuracy on the order of 1 m for the spacecraft line-of-sight distance. p... | advanced ranging instrumentation |
west (tungsten environment in steady-state tokamak) is starting operation for the first time with a water-cooled full tungsten divertor, enabling long pulse operation. heating is provided by radiofrequency systems, including lower hybrid current drive (lhcd). in this context, a compact multi-energy hard x-ray camera ha... | spatial calibration and synthetic diagnostic of a multi-energy hard x-ray camera at west tokamak |
nonlinear ultrasonic techniques have significant advantages in characterizing incipient defects of materials. the classical nonlinear ultrasonic theory indicates that a primary longitudinal wave can generate a second harmonic longitudinal wave due to the material nonlinearity (mn) or contact acoustic nonlinearity (can)... | on the emergence of the second harmonic shear horizontal wave in presence of tangential prestress |
in 2009, the multinational greenland ice sheet monitoring network (glisn) was initiated to monitor seismic events in and around the greenland. japan has been sending a field team to greenland each year since 2011, to construct and maintain the glisn stations especially on ice. however, the thick and heterogeneous green... | seismic waveform modelings for estimating influence of the ice sheet on observed seismograms |
today seismological observation systems combine broadband seismic receivers, hydrophones and micro-barometers antenna that provide complementary observations of source-radiated waves in heterogeneous and complex geophysical media. exploiting these observations requires accurate and multi-physics - elastic, hydro-acoust... | high-order hybridized discontinuous galerkin (hdg) method for wave propagation simulation in complex geophysical media (elastic, acoustic and hydro-acoustic); an unifying framework to couple continuous spectral element and discontinuous galerkin methods |
delamination is inevitable during either fabrication or service of a carbon fiber reinforced polymer (cfrp) component. these flaws are major degradation phenomena that are difficult to be detected by nondestructive testing techniques, especially for closed delamination. this study performed an experimental investigatio... | detection and quantification of artificial delaminations in cfrp composites using ultrasonic thermography |
material elastic moduli are used to assess stiffness, elastic response, strength, and residual life. ultrasound (us) measurements of propagation wave speeds (for longitudinal and shear waves) are now primary tools for non-destructive evaluation (nde) of elastic moduli. most us techniques measure the time-of-flight of t... | simultaneous determination of young's modulus and poisson's ratio in metals from a single surface using laser-generated rayleigh and leaky surface acoustic waves |
the recent pandemic is the first stage of a worldwide spreading diseases manifold1. the events of new complex viruses" network are in results of some universal and natural processes2; therefore, all the mechanisms related to these types of complex viruses" pandemics must be handled and taken considering its true nature... | natural cooperation of seismic activities related wave propagation on the worldwide pandemics processes |
transformation optics (to) has been recognized as an established scheme that can precisely manipulate electromagnetic surface wave propagations. utilising the advantages of the to technique, we proposed a to device which can control the propagation direction of surface waves. the device is based on a generalized eaton ... | surface wave direction control on curved surfaces |
a high-altitude nuclear explosion (hane) at low latitudes creates an artificial radiation belt of mev electrons by beta decay of radioactive fission fragments. the hane belt can be much more intense than the natural radiation belts and, depending on the l drift shell where hane electrons are created, could last for ver... | radiation belt remediation with artificial injection of plasma waves |
the mathematical modeling of the physical phenomenon of conduction in the presence of heat sources has various uses in engineering ranging from heat diffusion, pollution generation in large cities and chemical reactions. from the mathematical theory, the study of physical phenomena with the presence of heat is approach... | applications of differential equations to model the physical phenomenon of heat transfer with an internal energy source |
the objective of the paper is to look at the propagation and reflection of plane waves in a thermo-diffusion isotropic medium. the reflection of plane waves in a thermo-diffusion medium was investigated in this study with reference to triple phase lag thermo-elasticity. the memory dependent derivative (mdd) is applied ... | memory dependent triple-phase-lag thermo-elasticity in thermo-diffusive medium |
in the field of non-destructive evaluation of structures, 2d and 3d imaging of internal flaws is a critical task. defect imaging allows making informed follow-up decisions based on the morphology of the flaw. this paper will present advances in ultrasonic tomography for the 2d and 3d visualization of internal flaws in ... | ultrasonic imaging using wave structure-based weights and global matched coefficients |
the envision mission, which is ongoing selection at esa, is a spacecraft in near-polar and low-altitude orbit around venus. a regular tracking of the spacecraft in such an orbit will allow to uniformize the spatial resolution of the gravity field solution and to improve the accuracy of its tidal component (k2 love numb... | the envision gravity experiment |
we present two local tsunami scenarios for the nankai trough, japan, an area of significant seismic risk, using gps-a and gnss velocities and two different plate interface geometries to better assess the slip deficit rate. we expand on the work of yokota et al. [2016, nature] by: (1) adding seafloor data collected by n... | tsunami scenario in the nankai trough, japan, based on the gps-a and gnss velocities |
mechanical disturbances associated with hazardous events—e.g., earthquakes, explosions (volcanic or man-made)—and severe weather - generate broad spectra of infrasound and acoustic-gravity waves (agws). these wave signals may provide diagnostic insight into the processes that generated them. they are routinely detected... | modeling of infrasonic and acoustic-gravity wave propagation, nonlinear evolution, and observable effects |
seismic migration is a promising data processing technique to construct subsurface images by projecting the recorded seismic data at surface back to their origins. there are numerous migration methods. among them, reverse time migration (rtm) is considered a robust and standard imaging technology in present day explora... | elastic reverse time migration (rtm) from surface topography |
nasa's mini-rf instrument on the lunar reconnaissance orbiter (lro) is currently operating in concert with the arecibo observatory (ao) in puerto rico and the goldstone deep space communications complex 34 meter antenna dss-13 to collect bistatic radar data of the moon. these data provide a means to characterize the sc... | mini-rf s- and x-band bistatic radar observations of the moon |
dam-break waves cause important morphological changes in channels with erodible bed as a consequence of the high velocity of the fluid and the resulting sediment transport process. these morphological changes have been experimentally studied mostly for the case of prismatic rectangular cross-section channels [1,2]. how... | 2d non-intrusive measurements of dam-break waves in channels with movable bed and width variations |
local resonances, formed by zero-group velocity (zgv) and cutoff frequency points, have been extensively studied using impulse-based approaches, such as pulse laser and impact echo. in this work, we showcase the electromechanical impedance (emi) technique as an option to extract and promote zero-group velocity and cuto... | promoting local resonances in waveguide structures using the electromechanical impedance method |
due to recent human activity many holm oak trees (quercus ilex l.) are planted in the public and private gardens in sardinia. at present many of these trees are afflicted by decay especially that caused by pathogenic fungi which produce tail disease and bark cancer. a field methodology using ultrasonic tomography suppo... | use of three-dimensional ultrasonic tomography to detect decay in a living adult holm oak (quercus ilex l.) in sardinia (italy) |
organic materials have proved very useful for many devices, ranging from organic light emitting diodes (oled) to waveguiding structures. one such organic material is tris(8-hydroxyquinoline)aluminum (alq3), whose high emission efficiency and electron mobility make it ideal for efficient high-quality oled displays. howe... | dynamics of singlet excitons in alq3 and magnetic mode switching in index matched organic waveguides |
nonlinear phenomena are common in nonlinear sciences and physical engineering, such as ocean engineering and marine physics, as well as fluid dynamics. nonlinear partial differential equations (pdes) are the most suitable model to describe the nonlinear behavior of wave phenomena. in this work, the lie symmetry method ... | analysis of lie invariance, analytical solutions, conservation laws, and a variety of wave profiles for the (2+1)-dimensional riemann wave model arising from ocean tsunamis and seismic sea waves |
locally resonant metamaterial beams made from flexible substrates with piezoelectric layers can exhibit bandgap and vibration attenuation properties. however, the bandgap properties of the electromechanical metamaterials are limited by the electromechanical coupling coefficient. in order to effectively overcome this li... | active tuning of the vibration and wave propagation properties in electromechanical metamaterial beam |
due to the excessive use of composites in the industrial field, many numerical modeling approaches dedicated to the characterization of such complex material by means of non destructive testing techniques were developed. in this paper, we present a numerical model dedicated to simulate the inspection of unidirectional ... | the fast computation of eddy current distribution and probe response in homogenized composite material based on semi-analytical approach |
radio occultation measurements are usually conducted concurrently with optical measurements. radio waves are transmitted from the spacecraft, refracted in the planetary atmosphere, and received at a ground station. from the measured atmospheric doppler shift, we can obtain a vertical temperature profile with a high acc... | cross-link radio occultation measurements of the venus atmosphere by using multiple small satellites |
we use the 3d magnetohydrodynamic code lare to model wave transport within noaa active region 12683. the simulation extends vertically from the photosphere to the low corona and includes gravitational stratification and a steep transition region to a high temperature corona. ar12683 consists of a leading negative polar... | modeling wave energy transport using a 3d mhd simulation of ar12683 |
despite their high manufacturing cost and structural deficiencies especially in tip regions, highly skewed propellers are preferred in the marine industry, where underwater noise is a significant design criterion. however, hydrodynamic performances should also be considered before a decision to use these propellers is ... | hydrodynamic and hydroacoustic computational prediction of conventional and highly skewed marine propellers operating in non-uniform ship wake |
in the context of finite-different time-domain (fdtd) methods, errors associated with numerical dispersion can be reduced by introducing high-order or error-optimized derivative approximations. although there exist various accuracy-enhanced fdtd techniques for modeling wave propagation within non-dispersive media, the ... | error-optimized finite-difference modeling of wave propagation problems with lorentz material dispersion |
in this paper a new collocation technique for constructing time-dependent absorbing boundary conditions (abcs) applicable to elastic wave motion is devised. the approach makes use of plane waves which satisfy the governing equations of motion to construct the absorbing boundary conditions. the plane waves are adjusted ... | local dirichlet-type absorbing boundary conditions for transient elastic wave propagation problems |
spin waves, also known as magnons, have the potential to play a vital role as information carriers in spintronics. their lower energy damping, short wavelength and spin intrinsic nature, promise high-speed data processing in conventional and quantum information transmission. although several experimental techniques hav... | visualization of spin-wave propagation dynamics using laser-free ghz stroboscopic transmission electron microscopy |
it has been known since the mid eighties that best wave energy conversion by oscillating bodies in irregular waves requires prediction of the incident wave profile (naito and nakamura, 1985). the prediction duration, typically 15-30 s, depends on the radiation impulse-response function, and the exciting force kernel of... | deterministic wave elevation prediction for real-time impedance matching control of wave energy devices in intermediate waters |
structural health monitoring (shm) is a multidisciplinary damage detection technique that incorporates various mechanisms, of which guided waves (gws) -based damage detection is one of the critical fields of research. to realize the complete process of shm, research on gws has concentrated on diagnosis and localization... | spatial domain localization method for multi-damage in plate-like structure based on coefficient matrix of reflected guided waves |
wedge wave is a kind of elastic wave propagation along the tip of a wedge. in this study, a brass wedge with an apex angle of 60° was used as the substrate test piece and periodic defects were designed at the wedge tips. laser ultrasonic technique and finite element analysis were used to investigate the influence of pe... | study of influence of periodic defects on the propagation of wedge waves using laser ultrasound technique and finite element analysis |
this paper presents analyses of reduced order models (rom) for wave propagation in media containing material defects. parametric roms based on pod (proper orthogonal decomposition) are used here to take into account parameters that characterize local defects such as center position, extension and magnitude (localized l... | parametric reduced order models for wave propagation in 1d media containing defects |
this paper begins a development of methods for addressing variable bottom topography in discontinuous galerkin numerical methods for multi-layer, variable-density models of ocean circulation. for numerical models of ocean circulation, it is a widespread practice to split the fast (external) and slow (internal) dynamics... | an automatically well-balanced formulation of pressure forcing for discontinuous galerkin methods for the shallow water equations |
the standard paradigm for seismic event monitoring is to scan waveforms from a network of stations and identify the arrival time of various seismic phases. a signal association algorithm then groups the picks to form events, which are subsequently located by minimizing residuals between measured travel times and travel... | detecting and locating seismic events without phase picks or velocity models |
focused ultrasound is the only truly transient, local and non-invasive technique able to induce safe blood-brain barrier opening (bbbo), technique used in parkinson or alzheimer diseases research. however, the presence of the skull in the path usually affects the focus characteristics (gain, beam width, shape and maxim... | transcranial propagation with an ultrasonic mono-element focused transducer |
the refractive index structure parameter cn2 provides crucial information regarding turbulent effects on electromagnetic wave propagation. we propose to use second-order turbulence closure techniques to predict cn2 based on boundary layer parameterizations in numerical weather prediction (nwp) models. this predictive a... | computing refractive index structure parameter cn2 in a numerical weather prediction model |
nanowire metamaterials are a class of composite photonic media formed by arrays of aligned plasmonic nanowires incorporated in dielectric substrates. numerous applications in modern optics can be realized through the study and understanding of light's interaction with nanowire metamaterials. depending on exact composit... | emission modulation and other applications of nonlocal plasmonic nanowire metamaterials |
matched field processing (mfp) is a technique to locate the source of a recorded wave field. it is the generalisation of beamforming, allowing for curved wavefronts. in the standard approach to mfp, simple analytical green's functions are used as synthetic wave fields that the recorded wave fields are matched against. ... | matched field processing for complex earth structure |
venus's extremely harsh surface temperature and pressure conditions pose serious technical challenges by preventing the use of traditional long duration seismic techniques to examine the planet's interior. the recording of atmospheric acoustic fluctuations by several appropriate remote-sensing techniques (balloon-based... | modeling seismically-induced acoustic waves on venus |
bioinspired methods for sound source localization offer opportunities for resource reduction as well as concurrent performance improvement in contrast to conventional techniques. usually, sound source localization requires a large number of microphones arranged in irregular geometries, and thus has high resource requir... | direction-of-arrival estimation for acoustic signals based on direction-dependent parameter tuning of a bioinspired binaural coupling system |
a novel lattice boltzmann method (lbm) with a pseudo-equilibrium potential is proposed for electromagnetic wave propagation in one-dimensional (1d) plasma photonic crystals. the final form of the lbm incorporates the dispersive effect of plasma media with a pseudo-equilibrium potential in the equilibrium distribution f... | a new lattice boltzmann scheme for photonic bandgap and defect mode simulation in one-dimensional plasma photonic crystals |
seismic oceanography can provide a two- or three-dimensional view of the water column thermocline structure at a vertical and horizontal resolution from the multi-channel seismic dataset. several seismic imaging methods and techniques for seismic oceanography have been presented in previous research. in this study, we ... | frequency-domain reverse-time migration with analytic green's function for the seismic imaging of shallow water column structures in the arctic ocean |
this paper presents an occupant localization technique that determines the location of individuals in indoor environments by analyzing the structural vibrations of the floor caused by their footsteps. structural vibration waves are difficult to measure as they are influenced by various factors, including the complex na... | a multi-sensor stochastic energy-based vibro-localization technique with byzantine sensor elimination |
the complex nature of the ocean has long presented a challenge for researchers in the field of oceanography, including in the area of underwater acoustics. as a result, significant efforts have been made to develop accurate numerical models to better understand and study the ocean. established models such as acoustic t... | high-performance computation toward large-scale underwater acoustics modelling |
transcranial focused ultrasound is a promising technique for noninvasive and spatially targeted diagnosis and treatment of brain diseases. acoustic lenses were designed to correct the skull-induced beam aberration, but these designs could only generate static focused ultrasound beams inside the brain. here, we designed... | binary acoustic metasurfaces for transcranial focused ultrasound |
in this work, we use a computational technique with multiple properties of consistency in order to approximate solutions of a bounded β-fermi—pasta—ulam lattice in two space dimensions subject to harmonic driving in two adjacent boundaries. the processes of nonlinear supratransmission and infratransmission are employed... | on the propagation of binary signals in a two-dimensional nonlinear lattice with nearest-neighbor interactions |
boiling histotripsy is a promising noninvasive ultrasonic technique that can be used to mechanically destroy solid tumours. in boiling histotripsy, the formations and dynamics of a boiling vapour bubble and cavitation clouds contribute towards mechanical tissue fractionation. whilst a number of numerical and experiment... | evidence of the formation of the shock scattering induced violent cavitation cluster during boiling histotripsy insonation: a numerical case study |
the seismic waves responsible for vibrating civil engineering structures undergo interference, focusing, scattering, and diffraction by the inhomogeneous medium encountered along the source-to-site propagation path. the subsurface heterogeneities at a site can particularly alter the local seismic wave field and amplify... | simulation of high-frequency rotational motion in a two-dimensional laterally heterogeneous half-space |
a continuum model of kp-type for the approximate calculation of the characteristics of electromagnetic waves propagating in an almost circular (azimuthally symmetric), closely packed bundle of parallel, identical, and metal carbon nanotubes (cnts) yields results in reasonably good agreement with the equivalent-multishe... | propagation of an electromagnetic wave based on a continuum model of kp-type in an almost circular bundle of packed metal nanotubes |
ultrasound (us) is an important imaging tool for skeletal muscle analysis. the advantages of us include point-of-care access, real-time imaging, cost-effectiveness, and absence of ionizing radiation. however, us can be highly dependent on the operator and/or us system, and a portion of the potentially useful informatio... | skeletal muscle assessment using quantitative ultrasound: a narrative review |
in this work, a novel local space-time domain collocation technique—space-time boundary moving least squares (bmls-st) method, which has been proposed for modeling 3d propagation problems in the 4d spatiotemporal domain. the transient wave equations are approximated by four 1d boundary shape functions on the x-, y-, z-... | space-time collocation meshfree method for modeling 3d wave propagation problems |
extreme ultraviolet (euv) waves are large-scale propagating disturbances observed in the solar corona, frequently associated with coronal mass ejections and flares. they appear as faint, extended structures propagating from a source region across the structured solar corona. to measure these waves, we have constructed ... | detecting and tracking large scale euv waves in the solar atmosphere |
internal tides / lee waves coupling : dynamics and impact on the ocean energy budgetyvan dossmann,lemta, université de lorraine, cnrs, nancy, france.callum shakespeare,climate and fluid physics, the australian national university, canberra, australia usual parameterizations of mixing in global models quantify independe... | internal tides / lee waves coupling : dynamics and impact on the ocean energy budget |
we present a simple but accurate correlation between an experimental characterization and a simple analytical prediction of a wave propagation induced by the impact of a pendulum in a box filled with fine sand; this research is based on optical measurements and was carried out using the digital image correlation techni... | optical characterization of a pendular impact |
understanding the response of the rock mass to mining is of key importance for the planning of mine operations as well as assessing and mitigating the seismic risk. for decades, studies have shown that passive source tomography, also called local earthquake tomography, can provide information on the rock mass response ... | stress monitoring potential of ambient noise interferometry in deep mine environments |
seismic while drilling (swd) is a promising borehole seismic technique with reduction of drilling risk, cost savings and increased efficiency. to evaluate the technical and economic benefits of this new technique, we carried out swd survey at well g130 in shengli oilfield of eastern china. well g130 is an evaluation we... | seismic while drilling case study in shengli oilfield, eastern china |
lightweight, carbon fiber reinforced composites are often selected for aerospace components but are prone to barely visible impact damage, caused by low velocity impacts, during service. guided-wave-based structural health monitoring (shm) techniques can efficiently detect impact damage impact in composite structures. ... | guided wave energy focusing and steering in composite laminates |
the finite element method (fem) and the boundary element method (bem) can numerically solve the helmholtz system for acoustic wave propagation. when an object with heterogeneous wave speed or density is embedded in an unbounded exterior medium, the coupled fem-bem algorithm promises to combine the strengths of each tec... | stable and efficient fem-bem coupling with osrc regularisation for acoustic wave transmission |
we use a newly developed 2-d elastic reverse time migration (rtm) imaging algorithm based on the helmholtz decomposition to test approaches for imaging the descending slab in subduction zone regions using local earthquake sources. our elastic rtm method is designed to reconstruct incident and scattered wavefields at de... | converted-wave reverse time migration imaging in subduction zone settings |
stadium-py is an open-source command-line tool designed for automated computation of receiver functions (rfs) and shear-wave splitting (sws) measurements. it uses many useful tools from obspy for data retrieval and processing and integrates them with existing open-source seismological packages for achieving complete au... | stadium-py: python command-line interface for automated receiver functions and shear-wave splitting measurements |
an important mechanism of oscillation and wave propagation in fragmented and blocky geomaterials such as rock masses and the earth's crust is the movement and rotation of the fragments/blocks as rigid bodies with deformation mainly residing at the interfaces. there are cases when the gouge in the interfaces is very wea... | rotational waves in fragmented and blocky geomaterials |
in this paper we report new advances on the detection of propagation anomalies within the earth-ionosphere waveguide (eiw) produced by external perturbations. these anomalies reflect changes of the subionospheric propagation properties of very low frequency waves within the eiw. we use vlf data provided by known instru... | recent advances in the study of subionospheric vlf wave propagation anomalies |
low frequency (elf: 3hz-3khz; vlf: 3-30 khz) waves in the ionosphere are generated by lightning discharges, signals of ground-based vlf transmitters, and emissions arising from an evolution of instabilities in the earth's radiation belts. ion cyclotron waves and whistler-mode waves generated in the lower ionosphere/atm... | ionospheric propagation of the whistler-mode waves generated near the ground |
in the simulation of lower-hybrid current drive in tokamaks ray-tracing is currently the workhorse simulation tool used to design experiments. however, ray-tracing has yet to be extensively validated against full-wave simulations. due to recent advancements in computation it is now possible to simulate lower-hybrid wav... | coupling of lower-hybrid full wave and 3d fokker-planck codes in weak damping scenarios |
in 2006 the national solar observatory’s (nso) global oscillation network group (gong) completed the upgrade of their magnetographs with new polarization modulators permitting, for the first time, proper inter-calibration of the magnetic field data from a global network of six different instruments. this development wa... | brief history of using gong for space weather forecasting |
using combinatorial optimization techniques we study the critical properties of the two- and three-dimensional ising models with uniformly distributed random antiferromagnetic couplings (1 ≤ji≤2 ) in the presence of a homogeneous longitudinal field, h , at zero temperature. in finite systems of linear size, l , we meas... | random-bond antiferromagnetic ising model in a field |
to understand the dynamics of a pathogen in an animal population, one must assess how the infection status of individuals changes over time. with wild animals, this can be very challenging because individuals can be difficult to trap and sample, even more so since they are tested with imperfect diagnostic techniques. m... | newcastle disease virus transmission dynamics in wild peridomestic birds in the united arab emirates |
the principles of building a meter for the continuity of gas-liquid flows in pipelines have been proposed, based on the polarized electromagnetic wave characteristics. a two-component flow in a pipeline has been analyzed considering the cross-sectional area of the flow in the pipeline. the judgment about the flow conti... | measuring the continuity of a gas-liquid flow in a pipeline |
the numerical simulation of propagating sound fields in two dimensions using partition of unity finite element method(pufem) technique is implemented in this work. pufem is one of the most practical methods developed to alleviate high computational cost of conventional finite element method when we deal with the medium... | development of partition of unity finite element method for the modelling of acoustic waves propagating through porous domain |
we used digital holographic vibrometry (dhv) as a non-destructive method to detect debonding areas in laminates made of aluminum and polymer (polylactide, polyvinylidene fluoride or polycarbonate). at low frequencies (up to 30 khz) a0 lamb waves were excited and the amplitude and the phase patterns of the vibration of ... | a non-destructive technique using digital holographic vibrometry and lamb waves for quality determination of polymer-metal laminates |
the aim of this work is to investigate the application of seismological noise-based monitoring for bridge structures. a large-scale two-span concrete bridge model with a build-in post-tensioning system, which is exposed to environmental conditions, is chosen as our experimental test structure. ambient seismic noise mea... | investigation of ambient noise seismological methods on a bridge model |
partial discharge (pd) has been used as a reliable diagnostic technique for high voltage equipment. uhf methods have been widely applied for the detection of electromagnetic waves emitted from pd source in high voltage equipment. em wave propagation produced by pd can be detected by using uhf sensors. this paper discus... | design and fabrication of double layer bowtie antenna with modification of wing edge as uhf sensor for partial discharge detection in air insulation |
soft electro-active (sea) materials can be designed and manufactured with gradients in their material properties, to modify and potentially improve their mechanical response in service. here, we investigate the nonlinear response of, and axisymmetric wave propagation in a soft circular tube made of a functionally grade... | nonlinear response and axisymmetric wave propagation in functionally graded soft electro-active tubes |
seismic anisotropy is investigated by performing an upper crust shear-wave splitting study in the western gulf of corinth (wgoc). the study area, which is a tectonic rift located in central greece, is one of the most seismically active regions in europe, characterized by a 10 to 15 mm/year extension rate in a nnw-sse d... | an upper crust shear-wave splitting study for the period 2013-2014 in the western gulf of corinth (greece) |
the d-region ionospheric electron density profile plays an important role in many applications, including long-range and transionospheric communications, and coupling between the lower atmosphere and the upper ionosphere occurs, and estimation of very low frequency (vlf) wave propagation within the earth-ionosphere wav... | estimating the d-region ionospheric electron density profile using vlf narrowband transmitters |
arched magnetoplasma structures that carry electrical current ubiquitously exist in the solar atmosphere and affect energetic phenomena. a variety of alfvén waves and oscillations (e.g., fast/slow/euv waves, global-kink, kelvin-helmholtz, and sausage-modes) have been detected in recent space and ground based observatio... | laboratory investigation of alfvén waves and kink-mode oscillations in an arched magnetized plasma |
the contents of this dissertation include investigations in magnetic resonance elastography (mre) using a preclinical 9.4 tesla small animal magnetic resonance imaging (mri) system along with synthetic materials that mimic the mechanical properties of soft human tissue. mre is used for studying the mechanical behavior ... | synchronous measuring techniques in parallel to mre: study of pressure, pre-tension, and surface dynamics |
powder clumps (cakes) has a significant effect on the flowability and stability of powders. powder caking is mainly caused by moisture migration due to wetting and environmental (temperature and humidity) changes. the process of moisture migration caking involves creating liquid bridges between the particles during con... | ultrasonic wave propagation in powders |
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