Wave Mechanics, Measurement, and Entanglement

This paper documents a study of concentration diffusion with complementary mechanical and electromagnetic wave measurements. The paper starts with a review of the fundamentals of interparticle forces and wave–geomedia interaction. Experimental data were collected during the diffusion of a high-concentration solution of potassium chloride through different soils with different boundary conditions. Bentonite and kaolinite contracted during diffusion. The interaction between the concentration gradient, true interparticle forces, and fabric changes produced a pore-water pressure front that advanced ahead of the concentration front. The complex permittivity changed with the advance of the concentration front, reflecting the decrease in moisture content and the increase in conductivity. Concentration diffusion affected shear wave propagation through changes in true interparticle forces. Bentonite showed a significant increase in shear wave velocity, whereas the velocity of propagation in kaolinite decreased. Published differences in the behavior of bentonite and kaolinite were compiled and hypotheses are proposed to explain observed phenomena. Key words : mechanical waves, electromagnetic waves, clays, diffusion, double layer.

This paper addresses two issues with regard to nonlinear ocean waves. (1) The first issue relates to the often-confused differences between the coordinates used for the measurement and characterization of ocean surface waves: The surface elevation and the complex modulation of a wave field. (2) The second issue relates to the very different kinds of physical wave behavior that occur in shallow and deep water. Both issues come from the known, very different behaviors of deep and shallow water waves. In shallow water one often uses the Korteweg-deVries that describes the wave surface elevation in terms of cnoidal waves and solitons. In deep water one uses the nonlinear Schrödinger equation whose solutions correspond to the complex envelope of a wave field that has Stokes wave and breather solutions. Here I make clear the relationships between the two ways of characterizing surface waves. Furthermore, and more importantly, I address the issues of matching the two types of wave behavior as the wave motion passes from deep to shallow water, or vice versa. For wave measurements we normally obtain the surface elevation with a wave staff, resistance gauge or pressure recorder for getting time series. Remote sensing applications relate to the use of lidar, radar or synthetic aperture radar for obtaining space series. The two types of wave behavior can therefore crucially depend on where the instrument is placed on the “ground track” or “field” over which the lidar or radar measurements are made. Thus the matching problem from deep to shallow water is not only important for wave measurements, but also for wave modeling. Modern wave models [Osborne, 2010, 2018, 2019a, 2019b] that maintain the coherent structures of wave dynamics (solitons, Stokes waves, breathers, superbreathers, vortices, etc.) must naturally pass from deep to shallow water where the nature of the nonlinear physics, and the form of the coherent structures, change. I address these issues and more herein. This paper is directed towards the development of methods for the real time measurement of waves by shipboard radar and for wave measurements by airplane and helicopter using lidar and synthetic aperture radar. Wave modeling efforts are also underway.

Dense jet behaviour in dynamic receiving environments

Particulate geomaterials can be uniquely studied with wave-based techniques. Electromagnetic and mechanical waves interact with the tested material, exciting different phenomena and revealing different information. Complementary wave measurements were implemented in a modified oedometric cell to study and to monitor different processes in geomaterials. The cell and the measuring devices are discussed, followed by a presentation of typical measurements conducted during consolidation, chemical diffusion, and cementation. The paper also includes a discussion of the most common computations and analyses involved in this type of test.

Electron cyclotron harmonic (ECH) waves, potential drivers for diffuse aurora precipitation, have been extensively investigated for decades. The generation mechanism of ECH waves, however, remains an open question. Theoretical work in 1970s has demonstrated that ECH waves can be excited by loss cone distributions of hot plasma sheet electrons. Recent THEMIS spacecraft observations, however, indicate that the waves can also be excited by low energy electron beams. Utilizing interferometry techniques to analyze the phase difference between electric potentials measured by individual probes on Electric Field Instrument antenna pairs on THEMIS spacecraft, we compute the wavenumber of both beam‐driven ECH waves and loss‐cone‐driven ECH waves. These wavenumber measurements as well as other wave properties obtained from spacecraft measurements prove to be consistent with expectation from linear instability analysis. This provides us with independent verification of the generation mechanism and linear dispersion relation of beam‐driven and loss‐cone‐driven ECH waves. Our statistical results demonstrate that the median value of the wave vectors of beam‐driven ECH waves, characterized by wave normal angles () less than 80°, is 0.011 m−1; and that of loss‐cone‐driven ECH waves, characterized by wave normal angles larger than 85°, is 0.00765 m−1. Direct wavenumber measurements of ECH waves allow us to better understand the interaction between ECH waves and electrons in Earth's magnetosphere.

Recently a method for the evaluation of pyroelectric profiles from thermal wave measurements has been introduced, which is based on the construction of a scanning function from the measured pyroelectric spectra. This procedure is extended for the application to thermal pulse data. Well adapted to the propagation behaviour of thermal waves, the scanning function algorithm avoids problems with oscillations and instabilities and delivers an approximated polarization distribution in a very simple and direct way. An on-line analysis of thermal data is possible, giving access to a thermal recording of dynamic processes. The mathematical procedure and its physical basis are given together with numerical and experimental examples.

Measuring the mechanical properties of low impedance rubbery polymers at acoustic frequencies is a challenging problem due to the small signal amplitudes, relatively high loss, and the long wavelength of stress waves. One such material is solid polyurea (PU), an elastomeric copolymer, which has excellent chemical, thermal, and mechanical properties and is widely used as a coating (e.g. in truck bed lining) or blast protection (advanced helmet designs and concrete structures) material. Moreover, due to its heterogeneous structure, PU has a wide transition of thermo-mechanical behavior from rubber-like to glassy compared to most engineering polymers, which translates to a broader loss spectrum in frequency domain. In this study, we have developed a new test technique by modifying the split Hopkinson pressure bar and using ball impact to measure Young’s storage and loss moduli of polyurea at kHz frequencies. This will therefore fill the frequency gap between the dynamic mechanical analysis (DMA) and ultrasonic (US) wave measurement. The measured Young’s storage and loss moduli from this technique are compared with the master curves of the moduli developed using experimental data of dynamic mechanical analysis and ultrasonic wave measurements. This technique is a direct measurement which provides more reliable data in the kHz frequency range and can be used to evaluate the reliability of other indirect estimations including master curves. The utility of this technique is not limited to polyurea and it can be used to characterize other low impedance materials at kHz frequencies.

Myocardial fibrosis is recognized as a physio-pathologic substrate of main cardiovascular syndromes such as myocardial infraction or heart failure. Knowing that fibrosis leads to increased myocardial stiffness, elastography techniques, such as shear wave imaging, has been showed to detect for the detection Fibrotic Tissue (FT) (Liver, arteries, …). However, its application on the heart still remain challenging. In this work we want to estimate the velocity of Mechanical Waves (MW) produced by natural cardiac events such as the aortic valve closure, propagating along the left ventricle (LV) wall. The two main objective are to visualize the propagation of MW in 3D and achieve a 3D elasticity map of the LV.

Modeling and simulating guided wave propagation in complex, geometric structures is a topic of significant interest in structural health monitoring. These models have the potential to benefit damage detection, localization, and characterization in structures where traditional algorithms fail. Numerical modelling (for example, using finite element or semi-analytical finite element methods) is a popular approach for simulating complex wave behavior. Yet, using these models to improve experimental data analysis remains difficult. Numerical simulations and experimental data rarely match due to uncertainty in the properties of the structures and the guided waves traveling within them. As a result, there is a significant need to reduce this uncertainty by incorporating experimental data into the models. In this paper, we present a dictionary learning framework to address this challenge. Specifically, use dictionary learning to combine numerical wavefield simulations with 24 simulated guided wave measurements with different frequency-dependent velocity characteristics (emulating an experimental system) to make accurate, global predictions about experimental wave behavior. From just 24 measurements, we show that we can predict and extrapolate guided wave behavior with accuracies greater than 92%.

Probe measurements of ICRF surface waves in the TORTUS tokamak

We investigate, both theoretically and by a differential interferometric technique, the behavior of large-wavelength capillary waves (of the order of 10-4 m) selectively excited at the surface of drops and bubbles with typical eigenfrequencies of the order of 102 Hz. The resonance peaks of gas bubbles or hydrocarbon drops in water (radius less than 1 mm) highlight anomalously small dissipation in the region of ultralow (sub-nanometric) oscillation amplitudes, reaching a plateau at higher amplitudes. This is in sharp contrast to the usual oscillating systems, where an anomalous behavior holds at large amplitudes alone. Dissipation is strongly dependent on the excited vibrational modes and, in spite of remarkable numerical differences, water-vapor and water-hydrocarbon interfaces exhibit the same overall trend. A phenomenological model was developed, based on the assumption that water possesses a threshold viscoelasticity, above which it behaves like a regular viscous fluid. The well-known Deborah number was then estimated within the anomalous region and found to lie in the range of viscoelastic fluids. In agreement with previous studies of nanohydrodynamics (e.g., atomic force microscopy measurements with sub-nanometric tip motions), the present one lends support to the idea that every self-aggregating fluid exhibits yield stress behavior, including classical Newtonian fluids like water. The essential requirement is that the applied perturbation lie below a critical threshold, above which viscous behavior is recovered. Our differential interferometric technique seems particularly suitable for this type of studies, as it allows measurement of long-wavelength capillary waves with sub-nanometric resolution on the oscillation amplitudes.

For a non-invasive laser treatment, a real-time and non-contact monitoring technique is needed. We have investigated the extent of the surface modification of root dentin using photoacoustic spectroscopy (PAS), and have discussed the applicability of PAS technique to in vivo monitoring during laser treatment. Temporal behaviors of laser-induced acoustic waves were measured with an audible microphone. The extent of the surface modification, such as morphological and chemical changes, was evaluated by using information on the ablation depth and absorption spectrum of the irradiated dentins. The morphological and chemical changes of the irradiated dentin are respectively available for caries removal and increased acid resistance for root surface caries therapy. From the observations, it was found that time-resolved measurement of acoustic waves leads to a real-time understanding on the extent of the morphological change of the irradiated dentin. We have demonstrated the applicability of an in vivo monitoring technique involving PAS for root surface caries therapy.

High temperature behaviour of spin waves in Fe 3-xMn xSi

In this study, we have succeeded to generate the shock wave in 3 mm inner diameter tube by using diaphragmless driver section that we developed. The laser differential interferometer is constructed for the measurement of the shock wave propagating in the small diameter tube. The Mach number of the shock wave and the density ratio across the shock wave can be calculated by the interferometric signal obtained from the shock wave measurement. The Mach number distributions along the axial direction of the tube and the relation between the shock wave location and the time are obtained. As a consequence, it is confirmed that the behavior of the shock wave propagating in small diameter tube shows remarkable deviations from the theory and Brouillette's model.

This paper concerns the collation, quality control, and analysis of single-point field measurements from fixed sensors mounted on offshore platforms. In total, the quality-controlled database contains 122 million individual waves, of which 3649 are rogue waves. Geographically, the majority of the field measurements were recorded in the North Sea, with supplementary data from the Gulf of Mexico, the South China Sea, and the North West shelf of Australia. The significant wave height ranged from 0.12 to 15.4 m, the peak period ranged from 1 to 24.7 s, the maximum crest height was 18.5 m, and the maximum recorded wave height was 25.5 m. This paper will describe the offshore installations, instrumentation, and the strict quality control procedure employed to ensure a reliable dataset. An examination of sea state parameters, environmental conditions, and local characteristics is performed to gain an insight into the behavior of rogue waves. Evidence is provided to demonstrate that rogue waves are not governed by sea state parameters. Rather, the results are consistent with rogue waves being merely extraordinary and rare events of the normal population caused by dispersive focusing.