Sound Wave Velocity Research Articles

Reliability of sonic tomography to detect agarwood in Aquilaria microcarpa Baill.

Gaharu, or agarwood, is a valuable nontimber forest product. Due to its economic value, agarwood has been subjected to overexploitation in Indonesia’s natural forests. The traditional practice for harvesting agarwood is to fell trees without any reliable techniques for predicting that agarwood is present. Sonic tomography may represent a technique to detect agarwood in a tree before felling it. A study was conducted to evaluate the reliability of sonic tomography (Picus® sonic tomography) to detect agarwood within Aquilaria microcarpa trees. Thirty-five A. microcarpa trees (diameter ≥ 15 cm) at an experimental forest area in Carita, Banten Province, were selected as sample trees. Four to six transducers were placed at measuring points around the trunks of sample trees at 20, 130, and 200 cm from the ground. The transducers were connected to a software system that could record sonic wave velocities within each sample tree and then convert the data into colored images. The results showed that sound wave velocities within sample trees ranged from 400 to 900 m/s with average value 700 m/s. There were no significant differences of sonic wave velocities among measuring points. Sample trees with high sonic velocity tended to have dark-colored tomographic images (dark brown), while the lower sonic velocities were denoted by light colors (green, violet, blue). These results respectively corresponded to healthy and deteriorated conditions of the sample trees. In conclusion, sonic tomography shows sufficient reliability to detect the presence of agarwood in trees.

Study of the Earth’s interior using measurements of sound velocities in minerals by ultrasonic interferometry

Abstract This paper reviews the progress of the technology of ultrasonic interferometry from the early 1950s to the present day. During this period of more than 60 years, sound wave velocity measurements have been increased from at pressures less than 1 GPa and temperatures less than 800 K to conditions above 25 GPa and temperatures of 1800 K. This is complimentary to other direct methods to measure sound velocities (such as Brillouin and impulsive stimulated scattering) as well as indirect methods (e.g., resonance ultrasound spectroscopy, static or shock compression, inelastic X-ray scattering). Newly-developed pressure calibration methods and data analysis procedures using a finite strain approach are described and applied to data for the major mantle minerals. The implications for the composition of the Earth’s mantle are discussed. The state-of-the-art ultrasonic experiments performed in conjunction with synchrotron X-radiation can provide simultaneous measurements of the elastic bulk and shear moduli and their pressure and temperature derivatives with direct determination of pressure. The current status and outlook/challenges for future experiments are summarized.

Elastic and anelastic properties of α- and b-quartz single crystals

The anisotropic complex Young’s modulus of synthetic quartz single crystals is investigated, using a symmetric three-point bending experimental setup in a Dynamic Mechanical Analysis (DMA) testing system. The storage modulus and the dissipation modulus are examined at ambient pressure between room temperature and 620°C, across the α - β phase transition (573°C). The moduli are determined from measured stress, strain and phase lag data of oriented single crystals at five to ten distinct frequencies between 0.5 and 20 Hz. Quartz shows a strong frequency and temperature dependence of its complex mechanical properties, especially in the vicinity of the α - β phase transition. Around 573°C, the storage modulus steadily increases with frequency, while the dissipation modulus reaches a maximum between 1 and 2 Hz. The observed elastic and anelastic behaviour can be well described by the Poynting-Thomson model, yielding low- and high-frequency limits of the Young’s modulus. This accounts for differences among published data obtained with different experimental techniques, where inconsistent Young’s moduli are reported for similar temperature conditions, especially close to the α - β phase transition. Softening of the Young’s modulus of α -quartz with increasing temperature is accompanied by a decrease of the dynamic viscosity over several orders of magnitude and can be described by two Arrhenian processes. Using published shear moduli and the derived dynamic viscosity, mean relaxation times are derived, which decline from > 1700 s to c -axis and from > 700 s to 0.5 s perpendicular to the c -axis of the crystal, when increasing the temperature from 59°C to 571°C. The ratio of storage to dissipation modulus corresponds to the seismic quality factor Q , a measure of the attenuation of seismic waves. It exhibits a strong frequency and temperature dependence and reaches a minimum at the α - β phase transition. Longitudinal sound wave velocities show significant dispersion of >6 % parallel and >14 % perpendicular to the c -axis of the crystal at 571°C, between 1 and 20 Hz. The characteristics of both attenuation and dispersion of seismic waves close to the α – β phase transition could be used as an in situ temperature probe for quartz-rich crustal rocks.

Application of ultrasonic wave celerity measurement for evaluation of physicochemical properties of olive oil at high pressure and various temperatures

High-pressure processing is a powerful technology for food preservation. The knowledge of foods properties in the high-pressure range is important to develop and optimize such processes by means of mathematical modeling and simulation. Ultrasonic methods are rapid, non-invasive and can be used to characterize foods like edible oils (e.g., composition, purity, and quality assessment). In this paper, they were applied for the investigation of physicochemical properties of olive oil at high pressure at different temperatures. The sound wave velocity was measured by the pulse-transmission method and the corresponding oil density was additionally determined from the monitoring of sample volume change. Measurements were conducted in the pressure range up to 600 MPa, for temperatures from 20 to 50 °C. Intermolecular free length, isothermal and adiabatic compressibility versus pressure were calculated using measured sound speed and density isotherms. Discontinuities in the measured isotherms of sound speed and density versus pressure indicate the presence of liquid-to-solid phase transitions. The kinetics of the liquid-to-solid phase transition was also investigated. The transformation times of olive oil augment with increasing temperature. This study can be broadened to other liquid foodstuffs to investigate the influence of temperature on their physicochemical properties at high pressure.

Structural, electronic, elastic and thermal properties of some transition metal CuX (X = Sc and Pd) intermetallics: A FP-LAPW study

A systematic theoretical study using ab initio density functional theory (DFT) based on full potential linearized augmented plane wave (FP-LAPW) method has been performed for the investigation of structural, electronic, thermal and elastic properties of AB-type non magnetic intermetallic compounds. The CuX compounds (X=Sc and Pd) belong to cubic cesium chloride (B2-type, Pm3m, space group, 221) structure. The exchange correlation energy is described in the three PBE-GGA, WC-GGA and PBEsol-GGA approximations. We have calculated the ground state properties such as lattice constant (a0), bulk modulus (B) and pressure derivative of bulk modulus (B′). The three independent elastic constants (C11, C12 and C44) are also reported. The Debye temperature is estimated from the average sound velocity. Our results are in good agreement with the experimental and previously presented other theoretical data. From electronic band structure (BS) and density of states (DOS), it can be revealed that these intermetallic compounds are metallic in nature. The mechanical properties predicted from the calculated values of elastic constants have also been reported. We have first time predicted the behaviour of elastic constants with pressure. The variation of elastic moduli, sound wave velocities and Debye temperature with pressure are also reported.

Elastic Properties of CaSiO3 Perovskite from ab initio Molecular Dynamics

Ab initio molecular dynamics simulations were performed to investigate the elasticity of cubic CaSiO3 perovskite at high pressure and temperature. All three independent elastic constants for cubic CaSiO3 perovskite, C11, C12, and C44, were calculated from the computation of stress generated by small strains. The elastic constants were used to estimate the moduli and seismic wave velocities at the high pressure and high temperature characteristic of the Earth’s interior. The dependence of temperature for sound wave velocities decreased as the pressure increased. There was little difference between the estimated compressional sound wave velocity (VP) in cubic CaSiO3 perovskite and that in the Earth’s mantle, determined by seismological data. By contrast, a significant difference between the estimated shear sound wave velocity (VS) and that in the Earth’s mantle was confirmed. The elastic properties of cubic CaSiO3 perovskite cannot explain the properties of the Earth’s lower mantle, indicating that the cubic CaSiO3 perovskite phase is a minor mineral in the Earth’s lower mantle.

Equation of state and elasticity of B2-type FeSi: Implications for silicon in the inner core

Ab initio molecular dynamics simulations and high-pressure experiments were performed to investigate the equation of state and the elasticity of B2-type FeSi at core pressure–temperature conditions. The P–V–T relationship was determined by ab initio molecular dynamics calculations, corrected according to the high-pressure experimental data. All three independent elastic constants for B2-type FeSi, C11, C12, and C44, were calculated from the computation of changes in the free energy generated by small strains. The elastic constants were used to estimate the moduli and seismic wave velocities at the core pressure–temperature conditions. The estimated density of FeSi was lower than that of hcp-Fe, whereas the compressional and shear sound wave velocities of FeSi were higher than those of hcp-Fe. The inner core model for a simple mixture of Fe and FeSi was able to explain the density and seismic wave velocities of the Preliminary Reference Earth Model (PREM) determined from the seismic observations. However, the estimated temperature at the top of the inner core was too high, at ∼6500K, for the inner core to become an iron–silicon solid alloy. This indicated that, if the inner core comprises two components, then silicon is excluded from the candidate light elements present in the inner core.

Structural and physical property characterization in the Wenchuan earthquake Fault Scientific Drilling project — hole 1 (WFSD-1)

The Wenchuan earthquake Fault Scientific Drilling project (WFSD) started right after the 2008 Mw 7.9 Wenchuan earthquake to investigate its faulting mechanism. Hole 1 (WFSD-1) reached the Yingxiu–Beichuan fault (YBF), and core samples were recovered from 32 to 1201.15 m-depth. Core investigation and a suite of geophysical downhole logs (including P-wave velocity, natural gamma ray, self-potential, resistivity, density, porosity, temperature, magnetic susceptibility and ultrasound borehole images) were acquired in WFSD-1. Integrated studies of cores and logs facilitate qualitative and quantitative comparison of the structures and physical properties of rocks. Logging data revealed that the geothermal gradient of the volcanic Pengguan complex (above 585.75 m) is 1.85 °C/100 m, while that of the sedimentary Xujiahe Formation (below 585.75 m) is 2.15 °C/100 m. In general, natural gamma ray, resistivity, density, porosity, P-wave velocity and magnetic susceptibility primarily depend on the rock lithology. All major fault zones are characterized by high magnetic susceptibility, low density and high porosity, with mostly low resistivity, high natural gamma ray and sound wave velocity. The high magnetic susceptibility values most likely result from the transformation of magnetic minerals by frictional heating due to the earthquake. The YBF exposed in WFSD-1 can be subdivided into five different parts based on different logging responses, each of them corresponding to certain fault-rocks. The high gamma radiation, porosity and P-wave velocity, as well as low resistivity and temperature anomalies indicate that the Wenchuan earthquake fault zone is located at 585.75–594.5 m-depth, with an average inclination and dip angle of N305° and 71°, respectively. The fact that the fracture directions in the hanging wall and footwall are different suggests that their stress field direction is completely different, implying that the upper Pengguan complex may not be local.

Propagation of sound waves through a spatially homogeneous but smoothly time-dependent medium

The propagation of sound through a spatially homogeneous but non-stationary medium is investigated within the framework of fluid dynamics. For a non-vortical fluid, especially, a generalized wave equation is derived for the (scalar) potential of the fluid velocity distribution in dependence of the equilibrium mass density of the fluid and the sound wave velocity. A solution of this equation for a finite transition period τ is determined in terms of the hypergeometric function for a phenomenologically realistic, sigmoidal change of the mass density and sound wave velocity. Using this solution, it is shown that the energy flux of the sound wave is not conserved but increases always for the propagation through a non-stationary medium, independent of whether the equilibrium mass density is increased or decreased. It is found, moreover, that this amplification of the transmitted wave arises from an energy exchange with the medium and that its flux is equal to the (total) flux of the incident and the reflected wave. An interpretation of the reflected wave as a propagation of sound backward in time is given in close analogy to Feynman and Stueckelberg for the propagation of anti-particles. The reflection and transmission coefficients of sound propagating through a non-stationary medium is analyzed in more detail for hypersonic waves with transition periods τ between 15 and 200 ps as well as the transformation of infrasound waves in non-stationary oceans.

Low-frequency electromagnetic field in a Wigner crystal

Long-wave low-frequency oscillations are described in a Wigner crystal by generalization of the reverse continuum model for the case of electronic lattice. The internal self-consistent long-wave electromagnetic field is used to describe the collective motions in the system. The eigenvectors and eigenvalues of the obtained system of equations are derived. The velocities of longitudinal and transversal sound waves are found.

Energetics, equation of state, and elasticity of NAL phase: Potential host for alkali and aluminum in the lower mantle

The new aluminous (NAL) phase and aluminous phase with calcium ferrite (CF) structure constitutes more than 25 volume % of the deeply subducted crust at lower mantle depths. Using first principle simulations, we calculate the energetics, equation of state, and elasticity of NAL phase with a widely varying composition including CaMg2Al6O12, NaNa2Al3Si3O12 and KNa2Al3Si3O12. Our calculations indicate the relative stability of NAL and CF phases is a sensitive function of pressure, temperature, and composition, with increasing pressure tending to favor the CF phase, and increasing temperature, Mg‐content and alkali‐content tending to favor the NAL phase. The sound wave velocities of the NAL phase is significantly lower than CF phases and other major lower mantle phases. In deeply subducted MORB and CC, the faster sound velocity of silica (SiO2) and its high‐pressure polymorphic phase is likely to be compensated with the slower sound wave velocities of NAL phase.

NONLINEAR SECOND SOUND WAVES IN SUPERFLUID HELIUM: INSTABILITIES, TURBULENCE AND ROGUE WAVES

Recent work on nonlinear second sound wave propagation and acoustic turbulence in superfluid 4 He is reviewed. Observations of direct and inverse turbulent energy cascades are described. The direct cascade arises due to the strong nonlinear dependence of the second sound wave velocity on its amplitude. The flux of energy injected at the driving frequency is transformed via successively higher harmonics until it is eventually attenuated by viscous dissipation at the short-wavelength edge of the spectrum. The onset of the inverse cascade occurs above a critical driving energy density, and it is accompanied by giant waves that constitute an acoustic analogue of the rogue waves that occasionally appear on the surface of the ocean. The theory of the phenomena is outlined and shown to be in good agreement with the experiments.

Structural studies and mechanical properties of some borate glasses doped with different alkali and cobalt oxides

Mixed alkali borate glasses doped with CoO, have been prepared by the melt quenching technique. Elastic properties and FT-IR spectroscopic studies have been employed to study the role of CoO and the mixed alkali effect on the structure of the investigated glass system. Elastic properties and Debye temperature have been investigated using sound wave velocity measurements at 4 MHz at room temperature. The density, molar volume and glass transition temperatures were employed to investigate the structure of these glasses. Infrared spectra of these glasses revealed that the borate network is affected by the increase in the concentration of CoO content and the mixed alkali oxides. These results are interpreted in terms of the change in the topology of these glass structures. The elastic moduli are observed to increase with the increase of CoO content due to the increased average bond connectivity.

Ion beam driven ion-acoustic waves in a plasma cylinder with negatively charged dust grains

An ion beam propagating through a magnetized potassium plasma cylinder having negatively charged dust grains drives electrostatic ion-acoustic waves to instability via Cerenkov interaction. The phase velocity of sound wave increases with the relative density of negatively charged dust grains. The unstable wave frequencies and the growth rate increase, with the relative density of negatively charged dust grains. The growth rate of the unstable mode scales as one-third power of the beam density. The real part of frequency of the unstable mode increases with the beam energy and scales as almost the one-half power of the beam energy.

Acoustic method of particle detection and its applications for geophysics studies by means of a neutrino beam: Homage to Prof. B.A. Dolgoshein (1930–2010)

Development of the acoustic method of particle detection is presented from the very beginning until current experiments and perspectives. In 1976, Askaryan and Dolgoshein suggested acoustic detection of ultra high energy neutrino in ocean by using an acoustic signal generated according to thermoacoustic mechanism. Practical realization of such project is going on now in several experiments. In 1983, De Rujula, Glashow, Wilson, Charpak presented a possibility to use neutrino beam produced by a multi-TeV proton synchrotron for purposes of geological research. Dedicated studies were started in the group of Dolgoshein. Results of Monte Carlo simulations and measurement of such acoustic signals on the test beams of 70GeV proton accelerator are reported. A new possibility to forecast the earthquakes using the measurement of the velocity of longitudinal sound waves in the region of earthquake by means of usage of neutrino beam as an underground source of acoustic waves is discussed.

Preparation and Elastic Moduli of Germanate Glass Containing Lead and Bismuth

This paper reports the rapid melt quenching technique preparation for the new family of bismuth-lead germanate glass (BPG) systems in the form of (GeO2)60–(PbO)40−x–(½Bi2O3)x where x = 0 to 40 mol%. Their densities with respect of Bi2O3 concentration were determined using Archimedes’ method with acetone as a floatation medium. The current experimental data are compared with those of bismuth lead borate (B2O3)20–(PbO)80−x–(Bi2O3)x. The elastic properties of BPG were studied using the ultrasonic pulse-echo technique where both longitudinal and transverse sound wave velocities have been measured in each glass samples at a frequency of 15 MHz and at room temperature. Experimental data shows that all the physical parameters of BPG including density and molar volume, both longitudinal and transverse velocities increase linearly with increasing of Bi2O3 content in the germanate glass network. Their elastic moduli such as longitudinal, shear and Young’s also increase linearly with addition of Bi2O3 but the bulk modulus did not. The Poisson’s ratio and fractal dimensionality are also found to vary linearly with the Bi2O3 concentration.

Self-induced acoustic transparency of three-component longitudinal-transverse pulses

The features of the nonlinear dynamics of three-component elastic pulses in a low-temperature crystal containing paramagnetic impurities of electron and nuclear spins have been analyzed in the slowly varying envelope approximation. The presence of the electron spin subsystem makes it possible to equate the velocities of longitudinal sound and transverse acoustic waves; as a result, all components of the strain field efficiently interact with each other through the nuclear spin subsystem. The system of equations for envelopes of harmonics of the components of the strain field and the spin variables has been derived. The relations between the amplitudes and phases of the components have been obtained, the spectral composition has been analyzed, and the regimes of acoustic transparency of three-component longitudinal-transverse pulses have been discussed.

Elasticity and anisotropy of Fe3C at high pressures

Using static electronic structure calculations, we determine the equation of state, the full elastic constant tensor and the sound wave velocities of cementite (Fe3C) at pressures up to 410 GPa. Fe3C is ferromagnetic (fm) at ambient pressures. Upon compression, the magnetic moment of the Fe atoms are gradually lost and, at around -62 GPa, Fe3C becomes non-magnetic (nm). We find that the pressurevolume results for the Fe3C (fm) phase are well represented by a Vinet equation of state with K0fm = 183 GPa, K0 = 5.9, and V0fm = 151.6 Å3 and that of the Fe3C (nm) phase are well represented by a Vinet equation of state with K0nm = 297 GPa, K0′ = 4.9, and V0nm = 143.2 Å3. A third-order Birch-Murnaghan equation of state formulation for the Fe3C (nm) phase yields similar parameters with K0nm = 304 GPa, K0 = 4.5, and V0nm = 143.3 Å3. At pressures relevant to the Earth’s inner core, the full elastic constant tensor of Fe3C (nm) reveals significant P-wave anisotropy (-10%). A crystal preferred orientation with the [110] directions of Fe3C aligned along the pole axis would be required to explain the inner core anisotropy. Comparing, pure hcp Fe and iron carbides with varying stoichiometry, we find that the shear wave velocity decreases linearly with the increasing C content.

41.2: Acoustooptical Scanning Holography 3D Image Capturing and Electronic Hologram Recording

AbstractNew approach for electronic hologram creation and 3‐dimensional image capturing on the basis of acoustooptical principles is considered. The features of acoustooptical interaction, such as spectral and spatial selectivity, relatively slow velocity of sound waves, ability for frequency shifting, simple method of optical heterodyning, easy way for angular and spatial control of optical beam give great advantages for creation of effective holographic system for 3D images capturing and reconstruction. Recent results of our investigation in this area such as new architecture of acoustooptical scanning holographical system as well as the estimation of main parameters are presented.

The influence of wood density on longitudinal wave velocity determined by the ultrasound method in comparison to the resonance longitudinal method

The paper deals with the relationship between density and the velocity of sound wave propagation in wood. The wave velocity was measured using the heartwood of doussie (Afzelia bipindensis), merbau (Intsia bijuga), panga panga (Miletia stuhlmannii Taub.), tigerwood (Astronium graveolens Jacq.) and zebrano (Microberlinia brazzavillensis) by the two methods: ultrasound and resonance longitudinal. The velocity measured by the ultrasound method was always higher than the values gained by the resonance longitudinal method. However, there is a high correlation between the results of both methods. A change in sound wave velocity due to a change in density was not confirmed for any of the species. A similar conclusion was reached in the comparison among species.