abstract stringlengths 3 192k | title stringlengths 4 857 |
|---|---|
the formation of nonlinear ion-acoustic waves is studied in a degenerate magnetoplasma accounting for quantized and trapped electrons. relying on the reductive perturbation technique (rpt), a three-dimensional zakharov kuznetsov (zk) equation is derived, admitting a solitary wave solution with modified amplitude and wi... | formation of ion-acoustic solitary waves in a degenerate plasma with landau quantization and trapped electrons |
identifying frequency and modeshape of vibration to which a given mechanical structure is subjected most of its operational time is a key issue in diagnostics of the technical condition of the machine. by evaluating these modal parameters, the sources of vibration, and thus the possible sources of damage can be identif... | frequency and modeshape evaluation of steam turbine blades using the metal magnetic memory method and vibration wave propagation |
this paper investigates the wave propagation behavior of a high-speed rotating laminated nanocomposite cylindrical shell. the small-scale effects are analyzed based on nonlocal strain gradient theory (nsgt). the governing equations of the cylindrical laminated composite nanoshell in a thermal environment were obtained ... | wave dispersion characteristics of high-speed-rotating laminated nanocomposite cylindrical shells based on four continuum mechanics theories |
knowledge of the fracturing processes can be important for the optimization of pressurized fluid injection operations in the deep underground rock mass. active and passive seismic monitoring techniques have been used in the field for tracking or mapping the propagating hydraulic fracture. although both these monitoring... | laboratory investigation of hydraulic fracturing in granitic rocks using active and passive seismic monitoring |
the work describes the wave propagation in a periodic structure formed by a linear spring-mass chain with local duffing non-linear resonators. the wave propagation of the system is studied using the floquet-bloch theorem combined with a perturbation approach to identify the dispersion relations in the nonlinear periodi... | impact of non-linear resonators in periodic structures using a perturbation approach |
we propose an algorithm based on hilbert space-filling curves to reorder mesh elements in memory for use with the spectral element method, aiming to attain fewer cache misses, better locality of data reference and faster execution. we present a technique to numerically simulate acoustic wave propagation in 2d domains u... | boosting memory access locality of the spectral element method with hilbert space-filling curves |
the behaviour of gap-graded granular materials – that is, mixtures of coarse and cohesionless finer grains with measurable differences in particle size – does not always conform to established frameworks of sand behaviour. prior research has revealed that the role of the finer particles on the stress–strain response, l... | using geophysical data to quantify stress transmission in gap-graded granular materials |
microseismic events generate compressive waves and shear waves, which can be recorded at receivers. we present a theory that shows how elastic p and s waves separately backpropagate to the original source location. these refocused p and s wavefields are free of singularities. we also demonstrate a technique that enhanc... | focusing of elastic waves for microseismic imaging |
the detection and monitoring of physical, chemical and biomedical parameters are increasingly reliant on fiber-optic sensing technology. of applicable optical methods, photonic crystal fiber (pcf) sensors show its potential as a sensitive technique in environmental, industrial, food preservation and medical application... | prospects of photonic crystal fiber for analyte sensing applications: an overview |
high frequency (hf) radio propagation, and applications such as over-the-horizon radar (othr), is sensitive to ionospheric disturbances caused by space weather. improved ionospheric modelling and monitoring techniques for the high-latitude and polar regions supports high quality othr long-range surveillance. one such i... | evaluation of the effect of sporadic-e on high frequency radio wave propagation in the arctic |
the azimuthal (az'l) processing of 3d full-azimuth full-offset p-p reflection seismic data can enable better imaging, thus yielding improved estimates of structure, lithology, porosity, pore fluids, in situ stress, and aligned porosity that flows fluids (macrofracture porosity). in the past 34 years, the oil and gas in... | seismic field data displaying azimuthal anisotropy, 1986–2020 |
the explosion at the ingolstadt oil refinery was widely recorded at seismic and infrasound stations deployed throughout central europe, to distances of several hundred to a thousand kilometres. this study focuses on the wealth of data recorded at infrasound stations in central and eastern europe, while from the many de... | a comprehensive study of infrasound signals detected from the ingolstadt, germany, explosion of 1 september 2018 |
we investigate the applicability of the soft and hard apodization techniques to suppress bessel beam intensity oscillations through varying several parametric quantities, which include the input pixel pitch, the quantized amplitude gray level number, the transverse wave vector, the incident wavelength and the amplitude... | applicability of the soft and hard apodization techniques to suppress bessel beam intensity oscillations |
we study the dynamics of solitary waves traveling in a one-dimensional chain of bistable elements in the presence of a local inhomogeneity ("defect"). numerical simulations reveal that depending upon its initial speed, an incoming solitary wave can get transmitted, captured, or reflected upon interaction with the defec... | phase space analysis of nonlinear wave propagation in a bistable mechanical metamaterial with a defect |
the biswas-arshed (ba) model is an essential wave propagation model in nonlinear optics and optical fibers. in this manuscript, the enhanced (g′ / g)-expansion method is taken into consideration. the ba model is used with this technique to locate visual soliton solutions. the solutions to the hyperbolic and trigonometr... | on nonlinear optical solitons of fractional biswas-arshed model with beta derivative |
we investigate diffraction of reduced traction shear waves applied at the faces of a stationary crack in an elastic solid with microstructure, under antiplane deformation. the material behaviour is described by the indeterminate theory of couple stress elasticity and the crack is rectilinear and semi-infinite. the full... | diffraction of antiplane shear waves and stress concentration in a cracked couple stress elastic material with micro inertia |
frame based decomposition of fields provides a rigorous, flexible and effective tool to represent planar source field distributions as summations of gaussian windows. the field radiated by each window can be approximated as a gaussian beam in its paraxial region. in this context, beam shooting and bouncing techniques h... | complex-source beam representation of the fields radiated by a gaussian window |
symmetry plays a key role in the processing and analysis of not only visual but also acoustic signals in various multidisciplinary areas. new innovative and environmentally friendly methods for extinguishing flames are still being sought worldwide. one of these techniques appears to be the acoustic method. a laboratory... | analysis of flame suppression capabilities using low-frequency acoustic waves and frequency sweeping techniques |
this work presents an angular and polarization multiplexing technique for synthetic aperture (sa) imaging in digital holographic microscopy by using a pair of phase-type spatial light modulators (slms) to achieve resolution enhancement through a single hologram acquisition. angular multiplexing is applied to adjust the... | angular-polarization multiplexing with spatial light modulators for resolution enhancement in digital holographic microscopy |
diagnoses of power transformers by partial discharge (pd) measurement are effective to prevent dielectric failures of the apparatus. ultra-high frequency (uhf) method has recently received attention due to its various advantages, such as the robustness against external noise and the capability of pd localization. howev... | novel simulation technique of electromagnetic wave propagation in the ultra high frequency range within power transformers |
the theory of plastic wave propagation finds its applications in many geotechnical earthquake engineering problems. in this paper, a linear isotropic hardening plastic material is chosen to investigate the plastic wave propagation in a semi-infinite media. the dynamic response of a semi-infinite bar subjected to a tria... | numerical simulation and absorbing boundary conditions for wave propagation in a semi-infinite media with a linear isotropic hardening plastic model |
information on the vertical angle of arrival (elevation) is crucial in determining propagation modes of high-frequency (hf, 3-30 mhz) radio waves travelling through the ionosphere. the most advanced network of ionospheric hf radars, superdarn (super dual auroral radar network), relies on interferometry to measure eleva... | application of ground scatter returns for calibration of hf interferometry data |
in this study, we intend to analyze the traveling and several other solitary wave solutions in the nonlinear low-pass electrical transmission line model using the new mapping method, the new extended auxiliary equation method, and the extended kudryashov method. a type of traveling and solitary wave solutions emerge, c... | construction of new traveling and solitary wave solutions of a nonlinear pde characterizing the nonlinear low-pass electrical transmission lines |
wave scattering provides profound insight into the structure of matter. typically, the ability to sense microstructure is determined by the ratio of scatterer size to probing wavelength. here, we address the question of whether macroscopic waves can report back the presence and distribution of microscopic scatterers de... | bridging three orders of magnitude: multiple scattered waves sense fractal microscopic structures via dispersion |
we present an analysis of solar dynamics observatory (sdo) observations of an x1.4 class flare on 12 july 2012 (sol2012-07-12t15:37l082c105), which was associated with a pronounced sunspot rotation in the associated active region. based on the magnetograms taken with the helioseismic and magnetic imager (hmi) on the sd... | relationship between sunspot rotation and a major solar eruption on 12 july 2012 |
sub-ionospheric very low frequency (vlf) radio wave propagation characteristics are the major tool to study the lower ionospheric heights mainly d-region. wait's 2-component exponential model is a well-known mechanism to understand the basic characteristics of this layer based on vlf remote sensing. this model deals wi... | numerical simulation of lower ionospheric reflection parameters by using international reference ionosphere (iri) model and validation with very low frequency (vlf) radio signal characteristics |
a coupled wave-vegetation simulation is presented for the moving effect of the coastal vegetation on tsunami wave height damping. the problem is idealized by solitary wave propagation on a group of emergent cylinders. the numerical model is based on general reynolds-averaged navier-stokes equations with renormalization... | simulations of moving effect of coastal vegetation on tsunami damping |
ground waves and sky waves measured 209 km and 250 km south of six triggered lightning flashes containing 30 strokes that occurred in the half-hour before sunset on 27 august 2015 are presented and analyzed. we use a cross-correlation technique to find the ionospheric effective reflection height and compare our results... | triggered lightning sky waves, return stroke modeling, and ionosphere effective height |
although the porosity is a crucial parameter for understanding the soil behavior under static and dynamic loading, estimating the porosity of unsaturated soil is difficult owing to the various input parameters required. the objective of this study is to suggest a technical method to obtain the level of porosity based o... | porosity estimation of unsaturated soil using brutsaert equation |
laser processing of optically transparent or semi-transparent, brittle materials is finding wide use in various manufacturing sectors. for example, in consumer electronic devices such as smartphones or tablets, cover glass needs to be cut precisely in various shapes. the unique advantage of material processing with fem... | time-resolved study of femtosecond laser induced micro-modifications inside transparent brittle materials |
context. helioseismic holography is an imaging technique used to study heterogeneities and flows in the solar interior from observations of solar oscillations at the surface. holographic images contain noise due to the stochastic nature of solar oscillations.aims: we aim to provide a theoretical framework for modeling ... | signal and noise in helioseismic holography |
boron neutron capture therapy (bnct) promises a bright future in cancer therapy for its highly selective destruction of cancer cells, using the 10b +n→7li +4 he reaction. it offers a more satisfactory therapeutic effect than traditional methods for the treatment of malignant brain tumors, head and neck cancer, melanoma... | 2.5 mev cw 4-vane rfq accelerator design for bnct applications |
underwater noise pollution is a by-product of marine industrial operations. in particular, the noise generated when a foundation pile is driven into the soil with an impact hammer is considered to be harmful for the aquatic species. in an attempt to reduce the ecological footprint, several noise mitigation techniques h... | noise reduction by the application of an air-bubble curtain in offshore pile driving |
context. retrograde rossby waves, measured to have significant amplitudes in the sun, likely have notable implications for various solar phenomena.aims: rossby waves create small-amplitude, very-low frequency motions, on the order of the rotation rate and lower, which in turn shift the resonant frequencies and eigenfun... | detection of rossby modes with even azimuthal orders using helioseismic normal-mode coupling |
accurate modeling of the sun's coronal magnetic field and solar wind structures requires inputs of the solar global magnetic field, including both the near and far sides, but the sun's far-side magnetic field cannot be directly observed. however, the sun's far-side active regions are routinely monitored by helioseismic... | inferring maps of the sun's far-side unsigned magnetic flux from far-side helioseismic images using machine learning techniques |
from aeroplane wings to overhead power lines, through giant blades of wind turbines, a build up of ice can cause problems ranging from impaired performance all the way to catastrophic failure. therefore, it is of the utmost importance to control or prevent ice formation, especially on the critical areas of a structure.... | ultrasonic inspection for ice accretion assessment: effects on direct wave propagation in composite media |
the presence of gouge in rock joints significantly affects the physical and mechanical properties of the host rock mass. wave-based exploration techniques have been widely used to investigate the effects of gouge fill on rock mass properties. previous research on wave propagation in gouge-filled joints focused on analy... | effects of gouge fill on elastic wave propagation in equivalent continuum jointed rock mass |
the high resolution wavevector analysis (hrwa) is presented and its application illustrated. extending the high resolution wavenumber analysis method [1] to 2d signals, it allows the wide-band and local characterization of the linear elastic behavior of anisotropic plates. the method belongs to the family of experiment... | the high-resolution wavevector analysis for the characterization of the dynamic response of composite plates |
in this work, we present the analysis of vlf/lf sub-ionospheric propagation data to study anomalies possibly related to very recent strong (m > 5.5) earthquakes (eqs) that occurred in the southeastern mediterranean in september–october 2021 and january 2022. we used the signal of one transmitter located at negev in ... | possible pre-seismic indications prior to strong earthquakes that occurred in southeastern mediterranean as observed simultaneously by three vlf/lf stations installed in athens (greece) |
the vertical ground motion of seismic surface waves launches acoustic waves into the atmosphere and induces ionospheric disturbances. disturbances due to rayleigh waves near the short-period airy phase appear as wavy fluctuations in the virtual height of an ionogram and have a multiple-cusp signature (mcs) when the flu... | interpretation of deformed ionograms induced by vertical ground motion of seismic rayleigh waves and infrasound in the thermosphere |
seismic-well tying is an important technique for correlating well-logging curves in depth with seismic traces in time. an appropriate seismic-well tying technique must account for two types of nonstationarity: the nonstationary time errors in the synthetic seismic trace caused by the inaccurate time-depth relationship ... | nonstationary seismic-well tying with time-varying wavelets |
magnetic resonance elastography (mre) is an elasticity imaging technique for quantitatively assessing the stiffness of human tissues. in mre, finite element method (fem) is widely used for modeling wave propagation and stiffness reconstruction. however, in front of inclusions with complex interfaces, fem can become bur... | numerical simulation of wave propagation through interfaces using the extended finite element method for magnetic resonance elastography |
we begin with a brief historical survey of discoveries of quasi-crystals and graphene, and then introduce the concept of transformation crystallography, which consists of the application of geometric transforms to periodic structures. we consider motifs with three-fold, four-fold and six-fold symmetries according to th... | spanning the scales of mechanical metamaterials using time domain simulations in transformed crystals, graphene flakes and structured soils |
evaporation duct is an ubiquitous natural phenomenon over the ocean and can be diagnosed by evaporation duct model. the model proposed by paulus and jeske and another model established by the american naval postgraduate school are the most widely used. they are called pj model and nps model, respectively. two methods a... | a comparison study of sensitivity on pj and nps models in china seas |
this study presents a total of 12008 shear wave splitting measurements obtained using the reference-station technique applied to direct s-waves from 106 earthquakes recorded at 143 seismic stations of the hi-climb seismic network. the results reveal significant anisotropy in regions of southern tibet where null or negl... | significant seismic anisotropy beneath southern tibet inferred from splitting of direct s-waves |
recent attention has been drawn to breaking reciprocity due to its astounding applications. metamaterials can be utilized to break the time-reversal symmetry of a system. this paper investigates the theoretical propagation of waves in a space-time modulating medium and presents a novel fourier series expansion for avoi... | an improved method for unidirectional mechanical wave propagation in a metamaterial beam |
structural health monitoring (shm) based upon operational modal analysis (oma) constitutes an increasingly mature and widespread technology in the conservation of historic structures. such techniques, while proved effective for assessing the global integrity of structures, may fail at detecting local damage with little... | automated operational modal analysis and ambient noise deconvolution interferometry for the full structural identification of historic towers: a case study of the sciri tower in perugia, italy |
we present homogenization technique for the uniformly discretized wave equation, based on the derivation of an effective equation for the low-wavenumber component of the solution. the method produces a down-sampled, effective medium, thus making the solution of the effective equation less computationally expensive. adv... | discrete wave equation upscaling |
context. we present the first high-cadence multiwavelength radial-velocity observations of the sun-as-a-star, carried out during 57 consecutive days using the stellar échelle spectrograph at the hertzsprung song telescope operating at the teide observatory.aims: our aim was to produce a high-quality data set and refere... | oscillations in the sun with song: setting the scale for asteroseismic investigations |
electromagnetic media with generic linear response provide a rich class of lorentz violation models. in the framework of a general covariant metric-free approach, we study electromagnetic wave propagation in these media. we define the notion of an optic tensor and present its unique canonical irreducible decomposition ... | skewon modification of the light cone structure |
in this study, a flexible ultrasonic transducer (fut) was applied in a laser ultrasonic technique (lut) for non-destructive characterization of metallic pipes at high temperatures of up to 176 °c. compared with normal ultrasound transducers, a fut is a piezoelectric film made of a pzt/pzt sol-gel composite which has ad... | the use of flexible ultrasound transducers for the detection of laser-induced guided waves on curved surfaces at elevated temperatures |
the application of shift cell technique is presented and discussed for periodic porous media described with equivalent fluid models: as it can be found in literature, it consists in a reformulation of classical floquet-bloch (f-b) conditions, in which the phase shift of the boundary conditions, related to wave propagat... | computation of dispersion diagrams for periodic porous materials modeled as equivalent fluids |
the numerical simulation of seismic wave propagation in realistic heterogeneous media, as sedimentary basins, is a key element of seismic hazard estimation. many numerical methods in two dimensions are based on unstructured triangular meshes and explicit time schemes. however, the presence of thin layers and tangential... | impacts of geometric model simplifications on wave propagation-application to ground motion simulation in the lower var valley basin (france) |
this paper discusses the applicability of free side edges to a thickness shear bulk acoustic resonators (tsbars) on a rotated y-cut lithium niobate plate for suppression of lateral energy leakage and the transverse mode resonances. it is shown both theoretically and experimentally that free edges are effective to suppr... | application of free side edges to thickness shear bulk acoustic resonator on lithium niobate for suppression of transverse resonances |
in this paper, blowhole defects of sub-millimeter diameter in an aluminum alloy are successfully detected by the laser ultrasonic (lu) technique. a q-switched and pulsed nd:yag laser is used for ultrasonic generation, and a laser doppler vibration meter is used for detection of ultrasound waves on the sample surface. t... | non-destructive detection of small blowholes in aluminum by using laser ultrasonics technique |
using empirical matched field processing (mfp), we compare 4 yr of continuous seismic data to a set of 195 master templates from within an active geothermal field and identify over 140 per cent more events than were identified using traditional detection and location techniques alone. in managed underground reservoirs,... | discovering new events beyond the catalogue—application of empirical matched field processing to salton sea geothermal field seismicity |
polyethylene (pe) pipe, particularly high-density polyethylene (hdpe) pipe, has been successfully utilized to transport cooling water for both non-safety- and safety-related applications in nuclear power plant (npp). though asme code case n755, which is the first code case related to npp hdpe pipe, requires a thorough ... | a review of nondestructive examination technology for polyethylene pipe in nuclear power plant |
acoustic multiple scattering by a cluster of cylinders in an acoustic medium is considered. a fast recursive technique is described which takes advantage of the multilevel block toeplitz structure of the linear system. a parallelization technique is described that enables efficient application of the proposed recursive... | acoustic multiple scattering using recursive algorithms |
we propose a new method to compute elastic properties of rocks from computed tomography (ct) images. a ct volume captures x-ray attenuation, which is scaled in a ct number unit. our method improves an existing segmentation-less method where the ct volume is directly converted to elastic property arrays without using se... | calculating effective elastic properties of berea sandstone using the segmentation-less method without targets |
in this paper, the problem of scattering and amplification of seismic waves by topographical and geological irregularities is addressed directly in the time domain through the scaled boundary finite-element method (sbfem). the quadtree domain decomposition technique is utilized for the sbfem discretization of the near ... | analysis of transient wave scattering and its applications to site response analysis using the scaled boundary finite-element method |
dispersive wave modes called tweek atmospherics produced by lightning strokes were observed using stanford university designed awesome vlf receiver system installed at the university of tunis el manar, tunisia (geog. lat. 36.50 ° n; lon. 10.08 ° e). about 84 tweek atmospherics were analyzed during geomagnetically quiet... | estimation of nighttime ionospheric d-region parameters using tweek atmospherics observed for the first time in the north african region |
the real structure of the lower ionosphere should be taken into account when propagation of extremely low frequency (elf) radio waves is modeled and the global electromagnetic (schumann) resonance in the earth-ionosphere cavity is studied. in the present work, we use a 2d telegraph equation (2dte) to estimate the effec... | impact of the ionospheric day-night non-uniformity on the elf radio-wave propagation |
in this paper, we investigate the use of a mass lumped fully explicit time stepping scheme for the discretisation of the wave equation with underlying material parameters that vary at arbitrarily fine scales. we combine the leapfrog scheme for the temporal discretisation with the multiscale technique known as localized... | fast mass lumped multiscale wave propagation modelling |
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: an axisymmetric ray tracing code supports both closed and open field lines plasmas |
as a complementary way to traditional wave-equation-based forward modeling methods, lattice spring model (lsm) is introduced into seismology for wavefield modeling owing to its remarkable stability, high-calculation accuracy, and flexibility in choosing simulation meshes, and so forth. the lsm simulates seismic-wave pr... | a perfectly matched layer technique applied to lattice spring model in seismic wavefield forward modeling for poisson's solids |
most hf radars operate in a monostatic or quasi-monostatic configuration. the collocation of transmit and receive facilities simplifies testing and maintenance, reduces demands on communications networks, and enables the use of established and relatively straightforward signal processing and data interpretation techniq... | bistatic and stereoscopic configurations for hf radar |
the present paper articulates a mathematical model for the propagation of horizontally polarised shear (sh) wave in an initially stressed composite layered structure under the influence of an impulsive line source. the initially stressed composite structure is comprised of a transversely isotropic fluid saturated porou... | influence of an impulsive source on shear wave propagation in a mounted porous layer over a foundation with dry sandy elastic stratum and functionally graded substrate under initial stress |
in this work, an acoustic lumped element technique has been developed to measure the dynamic bulk modulus of porous materials in the low frequency range (f<500 hz). based on the electroacoustic analogy of wave propagation inside a porous medium, an analytical derivation of the measurement method is given. unlike oth... | low frequency acoustic method to measure the complex bulk modulus of porous materials |
we propose a method for defining the optimal locations of a network of tsunameters in view of near real-time tsunami forecasting using sea surface data assimilation in the near and middle fields, just outside of the source region. the method requires first the application of the empirical orthogonal function analysis t... | sea surface network optimization for tsunami forecasting in the near field: application to the 2015 illapel earthquake |
the implementation of increasingly complex periodic structures for vibro-acoustic purposes in civil engineering and transportation industry creates new modeling and computational challenges, mainly due to the multi-scale nature of the structures. homogenization techniques able to describe the local dynamics effects app... | diffusion based homogenization method for 1d wave propagation |
in this paper, the elastic wave propagation method was used in damage detection in thin structures. the effectiveness and accuracy of the system based on the wave propagation phenomenon depend on the number and localization of the sensors. the utilization of the piezoelectric (pzt) transducers makes possible to build a... | on transducers localization in damage detection by wave propagation method |
in this study, a non-contact laser ultrasonic propagation imaging technique was applied to detect the damage of plate-like structures. lamb waves were generated by an nd:yag pulse laser system, while a galvanometer-based laser scanner was used to scan the preliminarily designated area. the signals of the structural res... | comparison study between rms and edge detection image processing algorithms for a pulsed laser uwpi (ultrasonic wave propagation imaging)-based ndt technique |
this paper investigates an effective method for measuring the thickness of highly attenuating materials using the acoustic radiation-induced quasi-static component (qsc) of a primary longitudinal wave (plw) at high frequency. the generated qsc features lower attenuation than the high-frequency plw, so the generated qsc... | high-frequency ultrasound-based thickness measurement of highly attenuating materials |
this paper considers the existence and stability of traveling wave solutions of the boussinesq-burgers system describing the propagation of bores. assuming the fluid is weakly dispersive, we establish the existence of three different wave profiles by the geometric singular perturbation theory alongside phase plane anal... | wave propagation and stabilization in the boussinesq-burgers system |
the solution of the eigenvalue problem in bounded domains with planar and cylindrical stratification is a necessary preliminary task for the construction of modal solutions to canonical problems with discontinuities. the computation of the complex eigenvalue spectrum must be very accurate since losing or misplacing one... | computation of eigenvalues and eigenfunctions in the solution of eddy current problems |
many non-destructive evaluation techniques are based on the study and assessment of guided wavefields. yet, the extent of the sensing region and the span of time over which wavefield data is acquired can be tremendous, resulting in an enormous amount of spatio-temporal data. as a result, reducing the burden of data acq... | spatio-temporal undersampling: recovering ultrasonic guided wavefields from incomplete data with compressive sensing |
we have used the radio occultation (ro) satellite data champ/gps (challenging minisatellite payload/global positioning system) for studying the ionosphere of the earth. a method for deriving the parameters of ionospheric structures is based upon an analysis of the ro signal variations in the phase path and intensity. t... | case study of inclined sporadic e layers in the earth's ionosphere observed by champ/gps radio occultations: coupling between the tilted plasma layers and internal waves |
cracked media are a common geophysical phenomena. it is important to study the propagation characteristics in boreholes for sonic logging theory, as this can provide the basis for the sonic log interpretation. this paper derives velocity-stress staggered finite difference equations of elastic wave propagation in cylind... | simulation of acoustic wave propagation in a borehole surrounded by cracked media using a finite difference method based on hudson’s approach |
in this study, we build multi-wave solutions of the kdv-5 model through hirota's bilinear method. taking complex conjugate values of the free parameters, various colliding exact solutions in the form of rogue wave, symmetric bell soliton and rogue waves form; breather waves, the interaction of a bell and rogue wave, an... | dynamical structures of multi-solitons and interaction of solitons to the higher-order kdv-5 equation |
large-amplitude variations in gps total electron content (tec) at pc5-6 (<6.67 mhz) frequencies have been observed, using a high data rate global positioning system (gps) receiver of the canadian high arctic ionospheric network. tec variations with peak-to-peak amplitudes of 2-7 tec units (1 tecu = 1016 el m-2) were... | large-amplitude gps tec variations associated with pc5-6 magnetic field variations observed on the ground and at geosynchronous orbit |
quantitative subsurface analysis with increased reliability is fascinating the post processing research in infrared imaging for non destructive evaluation. accompanied by a variety of post processing approaches, non stationary thermal wave imaging has been emerging as a reliable technique to cater to anomaly detection ... | artificial neural networks based quantitative evaluation of subsurface anomalies in quadratic frequency modulated thermal wave imaging |
the ionospheric sporadic e (es) layer has significant impact on radio wave propagation. the traditional techniques employed for es layer observation, for example, ionosondes, are not dense enough to resolve the morphology and dynamics of es layer in spatial distribution. the ground-based global navigation satellite sys... | strong sporadic e occurrence detected by ground-based gnss |
this paper presents a concept for vibration-mitigation techniques with the potential to reduce ground vibration amplitudes by applying an additional vibration source. the idea of an additional generator is verified in the case of an impact load for the points located on the ground surface and below it. equations of mot... | the efficiency of an active generator in the case of a deep foundation location |
the perfectly matched layer (pml) is an efficient absorbing technique for numerical wave simulation. the complex frequency-shifted pml (cfs-pml) introduces two additional parameters in the stretching function to make the absorption frequency dependent. this can help to suppress converted evanescent waves from near graz... | importance of double-pole cfs-pml for broad-band seismic wave simulation and optimal parameters selection |
understanding the internal structure of an asteroid has important implications for interpreting its evolutionary history, for understanding its continuing geological evolution, and also for asteroid deflection and in-situ space resource utilisation. given the strong evidence that asteroids are seismically active, an in... | probing the internal structure of the asteriod didymoon with a passive seismic investigation |
high-resolution multipoint simultaneous structure-function analysis is becoming of great interest in a broad spectrum of fields for deciphering multiscale dynamics, especially in biophysics and materials science. however, current techniques are limited in terms of versatility, resolution, throughput, and biocompatibili... | array atomic force microscopy for real-time multiparametric analysis |
in the present article, we describe a few simple and efficient finite volume type schemes on moving grids in one spatial dimension combined with an appropriate predictor–corrector method to achieve higher resolutions. the underlying finite volume scheme is conservative, and it is accurate up to the second order in spac... | numerical simulation of conservation laws with moving grid nodes: application to tsunami wave modelling |
the solar mean magnetic field (smmf) provided by the wilcox solar observatory (wso) is compared with the smmf acquired by the helioseismic and magnetic imager (hmi) onboard the solar dynamics observatory (sdo). we found that despite the different spectral lines and measurement techniques used in both instruments, the p... | using sdo/hmi magnetograms as a source of the solar mean magnetic field data |
we report the adiabatic elastic constants of single-crystal thorium dioxide over a temperature range of 77 - 350 k. time-domain brillouin scattering (tdbs), an all-optical, non-contact picosecond ultrasonic technique, is used to generate and detect coherent acoustic phonons that propagate in the bulk perpendicular to t... | temperature-dependent elastic constants of thorium dioxide probed using time-domain brillouin scattering |
we present a three-dimensional (3d) numerical solver of the linearized compressible euler equations (global acoustic linearized euler), used to model acoustic oscillations throughout the solar interior. the governing equations are solved in conservation form on a fully global spherical mesh (0 ≤ ϕ ≤ 2π, 0 ≤ θ ≤ π, 0 ≤ ... | helioseismic modeling of background flows |
atomistic methods have successfully modeled different aspects of shock wave propagation in mate-rials over the past several decades, but they suffer from limitations which restrict the total runtime and system size. multiscale methods have been able to increase the length and time scales that can be modeled but employi... | moving window techniques to model shock wave propagation using the concurrent atomistic-continuum method |
this book introduces parabolic wave equations, their key methods of numerical solution, and applications in seismology and ocean acoustics. the parabolic equation method provides an appealing combination of accuracy and efficiency for many nonseparable wave propagation problems in geophysics. while the parabolic equati... | parabolic wave equations with applications |
we develop an algorithm for automatic identification of fault zone trapped waves in data recorded by seismic fault zone arrays. automatic s picks are used to identify time windows in the seismograms for subsequent search for trapped waves. the algorithm calculates five features in each seismogram recorded by each stati... | an algorithm for automated identification of fault zone trapped waves |
shock responses of amorphous polyethylene (ape) were characterized utilizing two different types of methodology, direct non-equilibrium molecular dynamics (nemd) and multi-scale shock technique (msst). providing a detailed physical view of the shock front itself, pico-second time resolved evolution of plasticity behind... | molecular insights into shock responses of amorphous polyethylene |
we use the rayleigh integral (ri) as an approximation to the helmholtz-kirchoff integral to model infrasound generation and propagation from underground chemical explosions at distances of 250 m out to 5 km as part of the source physics experiment (spe). using a sparse network of surface accelerometers installed above ... | modelling infrasound signal generation from two underground explosions at the source physics experiment using the rayleigh integral |
this paper investigates the propagation of rayleigh surface waves in a rotating semi-infinite solid medium, permeated by an initial magnetic field in the context of linear nonlocal elasticity. frequency equations are derived and the combined effect of magnetic field and rotation on rayleigh wave propagation, based on t... | rayleigh wave in a rotating nonlocal magnetoelastic half-plane* |
currently, data-driven models of solar activity forecast are investigated extensively by using machine learning. for model training, it is highly demanded to establish a large database which may contain observations coming from different instruments with different spatio-temporal resolutions. in this paper, we employ d... | super-resolution of solar magnetograms using deep learning |
we present a comparison of the spin wave propagation in au/y3fe5o12 and pt/y3fe5o12 bilayers. microwave technique with a co-planner waveguide arrangement was used to excite and detect the spin wave. we observed a suppression in the propagating spin wave intensity when a metal stripe is placed on the surface of y3fe5o12... | spin wave modulation by topographical perturbation in y3fe5o12 thin films |
the lattice boltzmann method (lbm) is a method to simulate fluid dynamics based on modelling distributions of particles moving and colliding on a lattice. the python scripting language provides a clean programming paradigm to develop codes based on the lbm, however in order to reach performance comparable to compiled l... | a concise python implementation of the lattice boltzmann method on hpc for geo-fluid flow |
based on the concept of the hybrid finite element (fe) analysis and statistical energy analysis (sea), a new hybrid method is developed for the mid-frequency vibration of a system comprising rectangular thin plates. the wave propagation method based on symplectic analysis is used to describe the vibration of the determ... | a hybrid wave propagation and statistical energy analysis on the mid-frequency vibration of built-up plate systems |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.