Types Of Waves Research Articles

Observation of interband Kelly sidebands in coupled-ring soliton microcombs

Kelly sidebands are a special type of dispersive wave that appear in mode-locked systems and they have recently been observed by pulsed excitation in integrated microcombs. Here, Kelly sidebands are generated by continuous-wave excitation in a partially coupled racetrack-resonator microcomb. The coupled-racetrack system supports two optical bands so that, in contrast to earlier studies, the soliton and Kelly sideband reside in distinct bands. The resulting interband excitation of the Kelly sidebands relaxes power requirements and continuous-wave sideband excitation is demonstrated. Tuning of sideband spectral position under pulsed excitation is also studied. Numerical simulation and the experiment show that the sidebands rely upon symmetry breaking caused by partial coupling of the two-ring system. More generally, multiband systems provide a new way to engineer Kelly sidebands for spectral broadening of microcombs.

Полосковый резонатор СВЧ с объемным кристаллом: экспериментальные характеристики и определение эффективной диэлектрической проницаемости

The paper presents the results of an experimental study and modeling of the frequency characteristics of a resonator in the form of two strip vibrators, separated by a large gap and covered with a bulk lithium niobate crystal. A metal electrode with a floating potential is installed on the upper surface of the crystal. The frequency dependences of the scattering matrix coefficients of a stripline resonator were measured in the frequency range up to 3 GHz. Electrodynamic analysis was carried out in the COMSOL Multiphysics numerical simulation environment. A comparison was made of experimental and numerical results, which showed good qualitative agreement between the transmission coefficients and reflection coefficients. Resonant oscillations were obtained at two or three frequencies depending on the location and orientation of the crystal. It has been established that at the first resonant frequency the electrode acts as a screen. The absence of an electrode leads to the disappearance of resonance. The simulation carried out in COMSOL made it possible to estimate the effective dielectric constant of the resonator corresponding to the values of the resonant frequencies. The calculation of electromagnetic fields made it possible to establish the types of waves corresponding to resonant frequencies. Knowing the type of waves and estimating the relative dielectric constant made it possible to construct an algorithm for a refined iterative procedure for calculating the values of the resonant frequencies and the effective dielectric constant of the resonator. The possibility of using resonators as single-link bandpass filters with a passband of about 1%, insertion loss of –1.1 dB and minimal return loss of –28 dB at the center frequency is shown.

Nonlinear random wave fields within a Boussinesq system

The dynamics of nonlinear random fields is important for understanding wave turbulence. In this work, we use a Boussinesq system to examine the distinctions between unidirectional and bidirectional waves. Our study demonstrates that in both scenarios, the wave spectra reach a stationary state. Moreover, we show that the occurrence of rogue waves is more probable in the unidirectional case. In the unidirectional case, the probability distribution of wave crests exceeds the one predicted by the Rayleigh distribution once the spectra reach the stationary state. Conversely, in the bidirectional case, the opposite trend is observed. The discovery of various types of rogue waves, including massive wave trains commonly known in the literature as “two sisters” and “three sisters” are found.

Effectiveness of Hae-Band in Measuring Hb Levels in Postpartum Hemorrhage Risk Monitoring

Postpartum hemorrhage is the main cause of high morbidity in the world (75%). Until now, efforts to early detect the risk of postpartum hemorrhage have still not been maximized. Sensor-based smartband can be the development of non-invasive methods in an effort to early detection of declining Hb levels in monitoring the risk of bleeding with practical, fast, precise, accurate, and practical. This research aims to determine the effectiveness of developing and analyzing the effectiveness of the "Hae-band" smartband in monitoring the risk of postpartum hemorrhage. The research method used is Research and Development (R&D), a quasi-experimental one-group pretest-posttest design using a nonequivalent dependent variable. The sampling technique in this research uses non-probability sampling with purposive sampling type. Respondents were selected by purposive sampling with a sample of 35 respondents maternity up to 6 hours postpartum to measure Hb levels and analyze the average levels of Hb and declining levels of HB Hae-band, HB meter POCT and visual estimation of blood loss volume compared with HB meter POCT (gold standard). Data analysis using the descriptive test, validation test, Paired T-Test, Independent T-Test, and multiple linear regression. The research results show that the Hae-band has been developed and is feasible as a measure of Hb levels which has a sensitivity of truth tool as much as 70.0% and can detect a decrease in Hb levels as much as 63.9% (p=0.000) more partially effective than visual estimation (0.24%) Smartband can detect Hb levels with good results compared to the gold standard of blood tests with a difference of 0.324 g/dL (p.0.113) with an average Hb levels at 6 hours PP at 11.19 g/dL compared to the average POCT 11.34 g/dL. This research concludes that Hae-band is more effective in detecting postpartum hemorrhage risk than visual estimation. It is hoped that further research can develop a more modern design where the sensor is more comfortable to use for long periods and has an alternative way of reading the sensor other than on the wrist. Improving accuracy, sensitivity, and higher battery power by improving the type of design, sensor, and wave type to be more suitable for measuring Hb levels can also be developed considering the efficiency of maternal monitoring and recording in the era of digitalization in early detection of bleeding risk.

Propagation attenuation of elastic waves in multi-row infinitely periodic pile barriers: A closed-form analytical solution

Periodically arranged media exhibit attenuation zones for elastic waves, and the related periodic structures play a crucial role in the design of seismic isolation and vibration mitigation. From the perspective of wave theory, this paper presents a closed-form analytical solution for the propagation attenuation of elastic waves through infinitely periodic, multi-row pile barriers. The innovative approach begins by deriving the extended Graf’s addition theorem to transform wave potentials across arbitrary coordinate systems, overcoming the constraints of traditional formulas that limit pile centers to linear configurations. Subsequently, it completes the wave function expansion by utilizing the phase differences in the frequency domain of wave fields around different periodic elements, thus skillfully integrating the effects of incident and scattered wave fields. For the first time, this study delivers exact expressions for the scattering of various types of plane waves (SH, SV, and P) by multi-row pile barriers with an infinite periodic array, addressing the complexities of large pile numbers in previous theoretical studies. The proposed solution increases computational efficiency by tens of times and markedly reduces the majority of resource usage, improving the analysis of complex vibration isolation systems involving numerous piles. Building on the accuracy verification and convergence analysis, several numerical examples are conducted to explore the effects of pile row, pile spacing, and pile arrangement on the propagation attenuation. The findings elucidate the mechanisms driving vibration reduction design using periodic wave barrier, furthering its application in engineering structures.

Shaking table tests for seismic response of jack-up platform with pile leg-mat foundation on sandy seabed

The pile leg-mat foundation is a novel composite foundation designed for jack-up offshore platforms. The seismic response of such foundations in sandy seabeds is an issue that requires significant attention. In this study, shaking table tests were conducted under various input seismic waves to investigate the dynamic response of a seabed platform system subjected to seismic loads. The effects of the peak ground acceleration (PGA), seismic wave frequency, wave type, pile leg insertion depth, and pile length on the response of the seabed platform system were investigated. The results indicated that as the PGA increased, the acceleration response of the soil and platform model increased, increasing the accumulation of excess pore water pressure and the horizontal displacement of the platform model. The acceleration and horizontal displacement responses of the seismic wave with lower frequencies were higher than those with higher frequencies. The peak acceleration amplification factors under the measured and regular seismic waves showed significant differences, with the dynamic response of regular waves to the platform model being pronounced. Under seismic waves with low PGAs, the horizontal displacement of the platform model decreased with increasing pile leg insertion depth or pile length.

Comparative analysis of viscous dissipation effects on Prandtl fluid including contraction and relaxation phenomena

AbstractThis paper investigates the effects of magnetohydrodynamics and heat transfer on the peristaltic transport of Prandtl fluid in a vertical endoscopic tube. The reduction of the complexity of the equations governing the flow of Prandtl fluid entails the use of long wavelength and low Reynolds number approximations. These complex equations for the pressure gradient and velocity profile are handled analytically using the perturbation technique with convective boundary conditions, and the temperature and concentration profiles are carefully solved for the exact solution. The frictional forces and pressure rise are also simulated with numerical integration. The resulting formulas for velocity, temperature, concentration, pressure rise, and pressure gradient are graphed using the MATLAB and MATHMATICA software, and the effects of all the different physical parameters are investigated and assessed. The streamlines with five distinct wave types are sketched at the conclusion to show the phenomenon of trapping. It is investigated that the velocity profile rises due to buoyancy forces and falls due to the influence of magnetic forces.

Study and Design of Corrugated Cardboard Trays With Microwaves by Experimental Analysis (EA) and Finite Element Methods (FEM)

ABSTRACTThe purpose of the work is to study by experimental analysis and finite element methods the mechanical response of a packaging, consisting of a corrugated cardboard container, used for the transport of fruit and vegetables. During the container design, three different configurations were selected which differ both in the choice of liner and in the type of wave. In particular, the type E, F and N microwaves were chosen. They are characterized by a lower amplitude than the high and medium waves commonly used in corrugated cardboard packaging, making it possible to reduce material consumption and, consequently, costs. In the initial phase of the study, experimental tests were performed to evaluate the mechanical strength of the liners. In addition, edge compression tests (ECTs) were performed to determine the stacking resistance of the structure. The break‐in resistance of the structures was analysed using a test conducted according to an internal standard, called strength packaging test (SPT). Subsequently, a parametric study was set up with the finite element method for the simulation of the mechanical behaviour of the three structures, using the homogenization technique. The comparison between the maximum total deformations, measured experimentally and calculated numerically, has highlighted the need to introduce corrective coefficients to improve the homogenization of the wave structure. In this way, it was possible to improve the matching of the results obtained on the structures simulated by the homogenization technique and those obtained on the corresponding real structures.

Three-dimensional analysis reveals diverse heat wave types in Europe

Heat waves are among the most studied atmospheric hazards but commonly investigated near-surface temperature patterns provide only limited insight into their complex structure. Here we propose and evaluate a novel approach to the analysis of heat waves as three-dimensional (3D) phenomena, employing the ERA5 reanalysis in three European regions during 1979–2022. Four types of heat waves based on their vertical cross sections of temperature anomalies are introduced: near-surface, lower-tropospheric, higher-tropospheric, and omnipresent. The individual heat wave types differ in length, predominant occurrence within summer, and soil moisture preconditioning. While near-surface heat waves may persist for more than 2 weeks, those located mainly in higher troposphere are shortest (5 days at most). This demonstrates that warm advection must be accompanied by a downward propagation of positive temperature anomalies through air subsidence and diabatic heating to maintain long-lasting heat waves. We also show that soil-moisture preconditioning is crucial for near-surface heat waves only, thus pointing to different driving mechanisms for the individual 3D heat wave types.

Application of multicomponent seismic data to tight gas reservoir characterization: A case study in the Sichuan Basin, China

Combining PP and PS waves from multicomponent data is an effective hydrocarbon characterization strategy because these two wave types are sensitive to different subsurface properties. We develop a case study using multicomponent data to characterize tight sandstone gas reservoirs in the Jurassic Shaximiao Formation, the western Sichuan Basin, China. In the study area, with PP data it is difficult to distinguish sandstones, mudstones, and gas sand, whereas recently acquired multicomponent data indicate potential for the joint characterization of lithology, porosity, and gas saturation from the combination of PP and PS reflections. Sandstones and mudstones have small P-wave velocity contrasts and large S-wave velocity contrasts. Thus, PS data provide a more accurate description of sandstones, as a substantial proportion of sandstones are undetectable from PP sections. P impedance is sensitive to sandstone porosity variation, and seismic-predicted porosities based on impedance inversion are in good agreement with log-interpreted porosities. The ratio of P-wave velocity to S-wave velocity is sensitive to gas accumulation, and the ratios derived from joint PP-PS prestack inversion are determined to be better than from PP prestack inversion in terms of their agreements with logs and distinct gas-sand boundaries.

Applications of nonlinear waves; lump wave, rogue wave, periodic wave, breather wave for a nonlinear model

In this work, we study the Chafee–Infante differential equation (CIDE) for various types of nonlinear waves (NW) like breather waves (BW), periodic cross-kink (PCKW), lump waves (LW), rogue waves (RW), periodic wave (PW), lump soliton (LS) with one kink, LS with two kink and periodic-cross lump waves (PCLW). The CIDE is a nonlinear evolution equation (NLEE) introduced by Nathaniel Chafee and Ettore Infante. This equation has been widely investigated in the context of pattern generation and soliton solutions, and it plays an essential role in understanding the complex nonlinear dynamics across a wide range of scientific fields. BW is a localized, non-dispersive solution to NW equations, maintaining shape and amplitude during travel. An LS is a type of solitary wave solution in NLEEs. In mathematics, RW refers to rare and unusually large solutions of NW equations. These waves have garnered significant attention due to their unpredictable and extreme nature. A PW is a type of wave that repeats its shape and behavior at regular intervals in both time and space. These waves are characterized by their periodicity, which means that they have a consistent and predictable pattern of oscillation. We’ll offer a graphical explanation of our newly discovered answers toward the conclusion.

Novel stochastic multi breather type, a-periodic, hybrid periodic and other type of waves of the Shrödinger–Hirota model with Wiener process

Novel stochastic multi breather type, a-periodic, hybrid periodic and other type of waves of the Shrödinger–Hirota model with Wiener process

Dyakonov surface waves in a thin interfacial waveguide formed by negatively anisotropic dielectrics.

Dyakonov surface waves (DSWs) are electromagnetic surface waves that exist at the interface of two dissimilar materials, with at least one material being anisotropic. Although there are various types of these waves, they all exist in anisotropic materials with positive anisotropy. The requirement for positive anisotropy limits the choice of materials that can support these waves. In this study, we present a type of Dyakonov surface wave that occurs at the interface of negatively anisotropic materials. Specifically, we demonstrate their existence in a system consisting of two negatively anisotropic slabs confined between two perfect electric conductor (PEC) walls. By assuming a small distance between the walls, we derive analytical expressions for the propagation constant, penetration depth, and field distribution of these surface waves. We numerically demonstrate that these surface waves can also exist in structures beyond the approximations used to develop the theoretical framework. The existence of Dyakonov surface waves in negative crystals broadens the range of materials suitable for their practical implementation.

Mathematical-Physics Analyses of the Nozzle Shaping at the Aperture Gas Outlet into Free Space under ESEM Pressure Conditions.

The paper presents a methodology that combines experimental measurements and mathematical-physics analyses to investigate the flow behavior in a nozzle-equipped aperture associated with the solution of its impact on electron beam dispersion in an environmental scanning electron microscope (ESEM). The shape of the nozzle significantly influences the character of the supersonic flow beyond the aperture, especially the shape and type of shock waves, which are highly dense compared to the surrounding gas. These significantly affect the electron scattering, which influences the resulting image. This paper analyzes the effect of aperture and nozzle shaping under specific low-pressure conditions and its impact on the electron dispersion of the primary electron beam.

Several nonlinear waves in spin quantum electron-positron plasmas

By using the reductive perturbation method, we obtained a nonlinear Schrödinger equation considering spin properties for a magnetized electron-positron plasmas. Several nonlinear wave were studied. The results indicate that various types of nonlinear waves exist in a magnetized electron-positron plasmas and they are spatially localized in both parallel and vertical directions to the external magnetized field direction. Additionally, the dependence of the wave amplitudes, wave width in both direction, group velocity of the envelop wave and the phase velocity of the background waves for these kinds of the nonlinear waves on the system parameters are all given in the present paper.

Wave type fiber SPR sensor for rapid and highly sensitive detection of hyperoside.

The fiber surface plasmon resonance (SPR) sensor used for the detection of active ingredients in traditional Chinese medicine has the problems of low sensitivity and difficult specific recognition. This paper proposed a wave type fiber SPR sensor, which reduced the mode of transmitted light through a periodic wave structure and caused concentrated and total reflection of the transmitted beam at the interface between the bent peak cladding and the air. A 50 nm gold film was coated on the surface of the cladding in the wave structure area to form the SPR sensing area. By controlling the width and height of the wave structure to control the total reflection angle of the transmitted light, i.e., the SPR incidence angle, the sensitivity of the fiber SPR sensor was effectively improved to 4972 nm/RIU. Furthermore, HSP90AA protein was modified on the gold film of the sensor to achieve specific detection of hyperoside. The longest single detection time was only 3 minutes, and the detection sensitivity was 0.53 nm/(µg/ml), with a detection limit as low as 0.68µg/ml, which is comparable to liquid chromatography. The proposed wave type fiber SPR sensor is fast in production and has high structural mechanical strength, providing a new approach for the rapid, highly sensitive, and specific detection of active ingredients in traditional Chinese medicine.

Resonating with the World: Thinking Critically about Brain Criticality in Consciousness and Cognition

Aim: Biofields combine many physiological levels, both spatially and temporally. These biofields reflect naturally resonant forms of synaptic energy reflected in growing and spreading waves of brain activity. This study aims to theoretically understand better how resonant continuum waves may be reflective of consciousness, cognition, memory, and thought. Background: The metabolic processes that maintain animal cellular and physiological functions are enhanced by physiological coherence. Internal biological-system coordination and sensitivity to particular stimuli and signal frequencies are two aspects of coherent physiology. There exists significant support for the notion that exogenous biologically and non-biologically generated energy entrains human physiological systems. All living things have resonant frequencies that are either comparable or coherent; therefore, eventually, all species will have a shared resonance. An organism’s biofield activity and resonance are what support its life and allow it to react to stimuli. Methods: As the naturally resonant forms of synaptic energy grow and spread waves of brain activity, the temporal and spatial frequency of the waves are effectively regulated by a time delay (T) in inter-layer signals in a layered structure that mimics the structure of the mammalian cortex. From ubiquitous noise, two different types of waves can arise as a function of T. One is coherent, and as T rises, so does its resonant spatial frequency. Results: Continued growth eventually causes both the wavelength and the temporal frequency to abruptly increase. Two waves expand simultaneously and randomly interfere in an area of T values as a result. Conclusion: We suggest that because of this extraordinary dualism, which has its roots in the phase relationships of amplified waves, coherent waves are essential for memory retrieval, whereas random waves represent original cognition.

Assessment of smell disturbances 6months after COVID-19 in Polish population.

Considering the frequency and severity of olfactory disorders associated with SARS-CoV-2 infection, attention to the olfactory loss has expanded. The aim of our study was to assess of smell disturbances 6months after COVID-19. The study population consisted of 2 groups: 196 Post-COVID-19 patients who were hospitalized because of COVID-19, control sample-130 patients without reported smell disorders from general population-Bialystok PLUS study. People from both groups were asked to participate in the Sniffin Sticks Test (half year after the disease). Sniffin Sticks Test consisted of 12 standardized smell samples. The participant's test score was counted based on correct scent recognition. Middle/older age was related with lower likelihood of olfaction recovery. The biggest differences in recognition of particular fragrances were observed for: orange and lemon, lemon and coffee (p.adj < 0.001). Patients had the greatest problem in assessing smell of lemon. The comparison of scores between Delta, Omicron, Wild Type, Wild Type Alpha waves showed statistically significant difference between Delta and Wild Type waves (p = 0.006). Duration of the disease (r = 0.218), age (r = -0.253), IL-6 (r = -0.281) showed significant negative correlations with the score. Statistically significant variables in the case of smell disorders were Omicron wave (CI = 0.045-0.902; P = 0.046) and Wild Type wave (CI = 0.135-0.716; P = 0.007) compared to Delta wave reference. Moreover, patients with PLT count below 150 000/μl had greater olfactory disorders than those with PLT count over 150 000/μl. There are: smell differences between post-COVID-19 patients and healthy population; statistically significant difference between Delta and Wild Type waves in Post-COVID-19 group in score of the Sniffin Sticks Test. Smell disturbances depend on the age, cognitive impairments, clinical characteristics of the COVID-19 disease and sex of the patient.

Hydrodynamic synchronization of elastic cilia: How surface effects determine the characteristics of metachronal waves.

Cilia are hairlike microactuators whose cyclic motion is specialized to propel extracellular fluids at low Reynolds numbers. Clusters of these organelles can form synchronized beating patterns, called metachronal waves, which presumably arise from hydrodynamic interactions. We model hydrodynamically interacting cilia by microspheres elastically bound to circular orbits, whose inclinations with respect to a no-slip wall model the ciliary power and recovery stroke, resulting in an anisotropy of the viscous flow. We derive a coupled phase-oscillator description by reducing the microsphere dynamics to the slow timescale of synchronization and determine analytical metachronal wave solutions and their stability in a periodic chain setting. In this framework, a simple intuition for the hydrodynamic coupling between phase oscillators is established by relating the geometry of flow near the surface of a cell or tissue to the directionality of the hydrodynamic coupling functions. This intuition naturally explains the properties of the linear stability of metachronal waves. The flow near the surface stabilizes metachronal waves with long wavelengths propagating in the direction of the power stroke and, moreover, metachronal waves with short wavelengths propagating perpendicularly to the power stroke. Performing simulations of phase-oscillator chains with periodic boundary conditions, we indeed find that both wave types emerge with a variety of linearly stable wave numbers. In open chains of phase oscillators, the dynamics of metachronal waves is fundamentally different. Here the elasticity of the model cilia controls the wave direction and selects a particular wave number: At large elasticity, waves traveling in the direction of the power stroke are stable, whereas at smaller elasticity waves in the opposite direction are stable. For intermediate elasticity both wave directions coexist. In this regime, waves propagating towards both ends of the chain form, but only one wave direction prevails, depending on the elasticity and initial conditions.

Dyakonov surface waves in dielectric crystals with negative anisotropy.

Since the initial discovery of Dyakonov surface waves at a flat infinite interface of two dielectrics, at least one of which is positively anisotropic, extensive research has been conducted towards their theoretical and experimental studies in materials with positive anisotropy. The potential applications of these waves were initially limited due to the stringent conditions for their existence and the requirement for position anisotropy. In our study, we present the theoretical prediction and experimental observation of a novel type of Dyakonov surface waves that propagate along the flat strip of the interface between two dielectrics with negative anisotropy. We demonstrate that the conditions for surface waves are satisfied for negatively anisotropic dielectrics owing to the specific boundaries of the strip waveguide confined between two metallic plates. We study such modes theoretically by using the perturbation theory in the approximation of weak anisotropy and demonstrate that the electromagnetic field distribution in these modes is chiral. Experimental verification of theoretical predictions is made in the microwave range using 3D-printed negatively anisotropic water-dielectric metamaterial slabs. The existence of Dyakonov surface waves in negative crystals prompts a reassessment of the list of materials suitable for practical realization of these waves in the visible and infrared ranges. Due to the ability of the considered modes to transmit chiral light, they have potential in the sensing of chiral organic molecules.