Order Wave Research Articles

Pemodelan Numerik Tsunami untuk Mengestimasi Waktu Tiba dan Ketinggian Maksimum Gelombang Tsunami di Teluk Amurang

Amurang Bay is a coastal area of South Minahasa Regency which is densely populated but faces the subduction zone of North Sulawesi which has the potential to generate earthquakes that trigger a tsunami. The process of the tsunami disaster occurred quickly, but the impact was very destructive and caused many casualties. This study aims to determine the propagation of tsunami waves with the worst scenario Mw 8.5 in Amurang Bay. Numerical methods in COMCOT software are used to model the propagation of tsunami waves in order to obtain an estimate of arrival time and maximum height of tsunami waves. Based on this modeling, the estimated arrival time of tsunami waves at the virtual tide gauge point in Amurang Bay is in the range of 8–11 minutes. The maximum height of tsunami waves is included in the alert category, which is 9.55 meters to 11.44 meters. The fastest estimated arrival time was recorded in Amurang Barat District and maximum height of tsunami waves was found in Tumpaan District. The results of this modeling can be used as one of the steps for mitigating tsunami disaster by preparing the surrounding community and assisting the evacuation process when a tsunami disaster occurs.

Anisotropic magnetism and electronic properties of the kagome metal SmV6Sn6

Kagome magnets are expected to feature emergent properties due to the interplay among geometry, magnetism, electronic correlation, and band topology. The magnetism and topological electronic states can be tuned via the rare-earth engineering in ${R\mathrm{V}}_{6}{\mathrm{Sn}}_{6}$ kagome metals, where $R$ is a rare-earth element. Herein, we present the synthesis and characterization of ${\mathrm{SmV}}_{6}{\mathrm{Sn}}_{6}$, a metal with two-dimensional kagome nets of vanadium and a frustrated triangular Sm lattice. Some of the Sm atoms are shifted from the normal $R$ positions by $c/2$ along the $c$ axis. Magnetic measurements reveal obvious anisotropy, where the easy magnetic axis is within the $ab$ plane. Electronic transport shows multiband behaviors below 200 K. Density functional theory calculations find that the electronic structure of ${\mathrm{SmV}}_{6}{\mathrm{Sn}}_{6}$ hosts flat bands, Dirac cones, and saddle points arising from the V $3d$ electrons near the Fermi level. No evidence for the existence of a charge density wave or magnetic order down to 2 K can be observed. Thus, ${\mathrm{SmV}}_{6}{\mathrm{Sn}}_{6}$ can be viewed as a modest disordered derivative of the ${R\mathrm{V}}_{6}{\mathrm{Sn}}_{6}$ structure, in which the disordered rare-earth ions can suppress the magnetic order and charge density wave in the ${R\mathrm{V}}_{6}{\mathrm{Sn}}_{6}$ kagome family.

Dirac pair in magnetized elliptic wormhole

In this manuscript, we investigate the evolution of a Dirac pair in a magnetized elliptic wormhole by solving the associated form of the covariant two-body Dirac equation. This equation includes spin algebra spanned by direct product of the generalized Dirac matrices and accordingly it leads 4 × 4 dimensional matrix equation for the considered system. We show that the matrix equation results in a non-perturbative second order wave equation. Solution of the wave equation is obtained in terms of the Confluent Heun function and then we try to obtain an energy expression. We observe that the evolution of the system depends on the parameters of the background as well as the magnetic field. Then, we analyse the results in detail.

Phase-resolved dynamic wavefront imaging of cilia metachronal waves.

The coordination and the directional order of ciliary metachronal waves are the major factors that determine the effectiveness of mucociliary clearance (MCC). Even though metachronal waves play an essential part in immune response, clinical diagnostic tools and imaging techniques that can reliably and efficiently capture their spatial distribution and function are currently limited. We present label-free high-speed visualization of ciliary metachronal wave propagations in freshly-excised tracheal explants using a spectrally-encoded interferometric microscope over a two-dimensional (2D) plane of 0.5 mm × 0.5 mm at an acquisition rate of 50 frame-per-second. Furthermore, phase-resolved enhanced dynamic (PHRED) analysis of time-series doppler images was performed, where spatial-temporal characteristics of cilia metachronal wave motions are revealed through frequency component analysis and spatial filtering. The PHRED analysis of phase-resolved Doppler (PRD) images offers a capability to distinguish the propagation direction of metachronal waves, and quantitatively assess amplitude and dominant frequency of cilia beating at each spatial location. Compared to the raw PRD images, the phase-resolved dynamic wavefront imaging (PRDWI) method showed the direction and coordination of collective cilia movement more distinctively. The PRDWI technique can have broad application prospects for the diagnosis of human respiratory diseases and evaluation of the curative effect of treatments and open new perspectives in biomedical sciences.

Wave Propagation in Vegetation Field by Combining Fast Multiple Scattering Theory and Numerical Electromagnetics in a Hybrid Method

To calculate scattering of a vegetation field consisting of a large number of plants, an improved fast version of the hybrid method (FHM) combining fast multiple scattering theory (FMST) and a numerical electromagnetic approach has been developed. In the HM, we use a library of T-matrices and the Foldy–Lax (FL) equation to calculate the electromagnetic field interactions outside of the cylinders enclosing the individual plants. To improve CPU time and memory requirements, the FL equation is solved by a triplet of fast Fourier transforms (FFTs) consisting of two FFTs solving 2-D FFTs of spatial distribution of plants and one 1-D FFT for solving the transformation of the order of cylindrical waves in the translation addition theorem. The triple FFTs minimize the CPU time and the memory requirement for computing translation addition matrix, which has been the bottleneck of large-scale simulations in the HM. To account for nonperiodic distribution of scatterers in a corn field, the premultiplication and the postmultiplication processes were applied to the FHM. The proposed method is validated at L-band (1.4 GHz) for 100 corn plants of height 1.25 m occupying an area of 9.54 by 9.54 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{m}^{2}$ </tex-math></inline-formula> . On a standard laptop, the CPU time is less than 6 min and the memory consumption is less than 710 Mbytes. The CPU time and the memory requirements are orders of magnitude more efficient than those required for solving the problem with a commercial software or using the previous version of the HM.

Numerical relativity higher order gravitational waveforms of eccentric, spinning, nonprecessing binary black hole mergers

We use the open source, community-driven, numerical relativity software, the Einstein Toolkit to study the physics of eccentric, spinning, nonprecessing binary black hole mergers with mass-ratios $q=\{2, 4, 6\}$, individual dimensionless spin parameters $\chi_{1z}=\pm0.6$, $\chi_{2z}=\pm0.3$, that include higher order gravitational wave modes $\ell\leq4$, except for memory modes. Assuming stellar mass binary black hole mergers that may be detectable by the advanced LIGO detectors, we find that including modes up to $\ell=4$ increases the signal-to-noise of compact binaries between $3.5\%$ to $35\%$, compared to signals that only include the $\ell=|m|=2$ mode. We use two waveform models, TEOBResumS and SEOBNRE, which incorporate spin and eccentricity corrections in the waveform dynamics, to quantify the orbital eccentricity of our numerical relativity catalog in a gauge-invariant manner through fitting factor calculations. Our findings indicate that the inclusion of higher order wave modes has a measurable effect in the recovery of moderately and highly eccentric black hole mergers, and thus it is essential to develop waveform models and signal processing tools that accurately describe the physics of these astrophysical sources.

Research on Strip Profile Control Characteristics of 1500 mm Quintic CVC Mill

Compared with cubic Continuously Variable Crown (CVC), quintic CVC presents integrated control capability of quadratic and quartic crown. In order to take full advantage of quintic CVC and have better comprehensive control of the edge wave, center wave, high order wave and complex wave in practical application, it is necessary to further clarify the complicated profile control characteristics of quintic CVC. In this paper, quintic CVC technology in a 1500 mm continuous hot rolling mill production line has been taken as the research object and use finite element method to study its profile control characteristics. Through finite element simulation, an integrated model of rolls and strip was established to analyze the influence of the shifting, bending force and rolling force on strip profile with different strip widths. Both crown adjustment area and transverse stiffness are gained to study the control capability of quintic CVC. The simulation results show that the positive shifting and positive bending of CVC work roll reduce the quadratic crown and increase the quartic crown, and the controlling effect of shifting on both quadratic and quartic crown is more remarkable than that of bending. The control capability of the crown increases with the increase of strip width. That is, wider strip has a larger crown adjustment area. Meanwhile, there is a strong coupling relationship that the increase of quadratic crown can lead to the decrease of the quartic crown, which is not good for the flexible control of strip profile. With the increase of rolling force, the quadratic crown of strip increases significantly, while the quartic crown does not change obviously. Additionally, the increase of strip width significantly increases the transverse stiffness of mill.

Multiple Quantum States Induced in 1T‐TaSe2 by Controlling the Stacking Order of Charge Density Waves

AbstractVan der Waals (vdW) materials afford unprecedented opportunities for control of electronic properties by utilizing the stacking degree of freedom. An intriguing frontier, largely unexplored, is the stacking of charge density wave (CDW) phases that is a broken‐symmetry state with periodically modulated charge density and the atomic lattice. Employing density functional theory, it is uncovered that the stacking order can play a significant role in the quantum phase transitions of layered 1T‐TaSe2 with a striking 2D CDW order. By controlling the vertical stacking order of CDWs, bulk 1T‐TaSe2 can host various electronic phases including quasi‐1D and 3D metals and band insulators. Particularly, the ground‐state stacking configuration shows 3D metallicity due to the enhanced intralayer and interlayer electron hopping, and the second lowest energy configuration shows band insulating behavior via interlayer dimerization, implying potential metal‐insulator transition. In ultrathin‐layer 1T‐TaSe2, not only the stacking order but also the thickness dictate the electronic properties. While the monolayer is a Mott insulator, the bilayer (trilayer) is a band insulator (metal). More interestingly, the four‐layer emerges as an insulator or a semimetal dependent on its stacking order. The wide‐tunable electronic properties of 1T‐TaSe2 CDW compound will open a new pathway for designing novel quantum devices.

The solutions of classical and nonlocal nonlinear Schr\"{o}dinger equations with nonzero backgrounds: Bilinearisation and reduction approach

In this paper we develop a bilinearisation-reduction approach to derive solutions to the classical and nonlocal nonlinear Schr\"{o}dinger (NLS) equations with nonzero backgrounds. We start from the second order Ablowitz-Kaup-Newell-Segur coupled equations as an unreduced system. With a pair of solutions $(q_0,r_0)$ we bilinearize the unreduced system and obtain solutions in terms of quasi double Wronskians. Then we implement reductions by introducing constraints on the column vectors of the Wronskians and finally obtain solutions to the reduced equations, including the classical NLS equation and the nonlocal NLS equations with reverse-space, reverse-time and reverse-space-time, respectively. With a set of plane wave solution $(q_0,r_0)$ as a background solution, we present explicit formulae for these column vectors. As examples, we analyze and illustrate solutions to the focusing NLS equation and the reverse-space nonlocal NLS equation. In particular, we present formulae for the rouge waves of arbitrary order for the focusing NLS equation.

Effect of Ambient Air Temperature on the Compression Wave Propagating along a Railway Tunnel

The parameters of the compression wave propagating in a railway tunnel are significantly influenced by the large ambient air temperature variation throughout the year. High-speed train entering a railway tunnel produces a wave of finite amplitude to propagate at sonic speed. The wave attenuates while propagation through viscous dissipation and inertial forces nonlinearly steepen the wave. As a result of the dependence of sound speed on air temperature, the wave characteristics are altered with changing temperature. Therefore, it is crucial to comprehend the impact of ambient air temperature on the properties of the compression wave in order to construct an aero-acoustically ideal railway tunnel system. The method of characteristics (MOC) has been used to solve Euler equations with steady and unsteady friction parameters in the current study. According to the findings, wave attenuation ratio is reducing along the tunnel length, and gradient is rising as train speed increases. The case study illustrates the key distance within a tunnel where the steepening ratio is at its highest point. This critical tunnel length is estimated to be 65 times the tunnel hydraulic diameter (300 km/h) for a particular air temperature (T = 323 K), and it decreases by 15% for a 70 K reduction (323K to 253K) in temperature. Similarly, the critical length falls by 40% for greater train speeds (500 km/h).

Complements to Level 2 surf-riding/broaching vulnerability criterion regarding waterjet propelled ships and wave surge force correction

The Second Generation Intact Stability Criteria (SGISC) has officially entered the trial period for further validations and to collect feedback based on applications. This study focuses on the Level 2 surf-riding/broaching vulnerability criterion and proposes complements to the assessment procedures regarding two important issues. One is that the current procedure is only applicable to ships using propellers. However, waterjet propelled ships are common nowadays and they may be vulnerable to this stability failure mode as well. The other issue is that there lacks a both reliable and practical method for the wave surge force correction. The current procedure uses the Froude-Krylov (FK) component of the first order wave surge force as the input for the assessment, which significantly over-estimates the probability of surf-riding occurrence.Through the introduction of the thrust coefficient KT and the advance coefficient J for waterjet systems, the first issue is addressed by model the waterjet thrust based on the KT ∼ J relationship just as that of propellers. The validity of such treatment is first demonstrated through the actual data of a real pump, while the rationale behind the universality of such modelling is analyzed based on dimensional analysis. The second issue is addressed through the proposal of a practical method to estimate the wave surge force correction factor based on the ratio between the first order wave surge force and its FK component. Sample ship calculations are performed to demonstrate the reliability of the proposed method. Finally, the complete Level 2 surf-riding/broaching vulnerability assessment for a waterjet propelled ship is performed for demonstration. This study contributes to the improvement of SGISC, making it applicable to a wider range of ship types with higher accuracy.

An energy-based discontinuous Galerkin method with tame CFL numbers for the wave equation

We extend and analyze the energy-based discontinuous Galerkin method for second order wave equations on staggered and structured meshes. By combining spatial staggering with local time-stepping near boundaries, the method overcomes the typical numerical stiffness associated with high order piecewise polynomial approximations. In one space dimension with periodic boundary conditions and suitably chosen numerical fluxes, we prove bounds on the spatial operators that establish stability for CFL numbers \(c \frac{\Delta t}{h} < C\) independent of order when stability-enhanced explicit time-stepping schemes of matching order are used. For problems on bounded domains and in higher dimensions we demonstrate numerically that one can march explicitly with large time steps at high order temporal and spatial accuracy.

Analysis and weakening of radial electromagnetic forces in high‐speed permanent magnet motors with external rotors based on shape functions

AbstractIn this paper, a strategy of integrating direct‐drive turbine compressors with high‐speed permanent magnet external rotor motors is used to improve the problems of large footprint, low efficiency and high maintenance costs. The rotor of the motor will vibrate under the action of radial electromagnetic force when rotating, and under the action of high pressure and high speed gas, it may aggravate the rotor vibration. In the case of changing the original mechanical structure of the turbine, the vibration of the motor rotor needs to be analysed. In the paper, the radial electromagnetic force applied to the rotor is analysed. The influence of the order and size of the stator and rotor magnetic field harmonics on the size, frequency and order of the radial electromagnetic force wave is summarised. In order to weaken the radial electromagnetic force, this paper proposes a shape function about the magnetic pole size and designs a magnetic pole accordingly. The validity of the shape function was confirmed by comparing the radial electromagnetic force wave with a conventional, surface‐mounted, built‐in magnetic pole structure. Finally, based on the analysis of the rotor dynamics mode, the law of the effect of the change of the pole arc coefficient of the pole on the radial force was analysed using harmonic response, and reasonable conclusions were drawn.

Reducing the Mutual Coupling of Cylindrical Circular Microstrip Antennas (CCMAs) Array Using EBG Structure

A theoretical study to design a conformal microstrip antennas was introduced in this work. Conformal microstrip antennas define antennas which can be conformed to a certain shape or to any curved surface. It is used in high-speed trains, aircraft, defense and navigation systems, landing gear and various communications systems, as well as in body wearable. Conformal antennas have some advantages such as a wider-angle coverage compared to flat antennas and low radar cross-sectional (RCS) and they are suitable for using in Radome. The main disadvantage of these antennas is the narrow bandwidth. The FDTD method is extremely useful in simulating complicated structures because it allows for direct integration of Maxwell's equations depending on time. The 1x2 cylindrical circular microstrip antennas array is designed and simulated vertically via Finite Difference Time Domain (FDTD) method where can directive antenna be achieved through antennas array design. Mutual coupling between the antennas in the array and the different separation between them were studied. The circular patch is excited by a probe feed method for several reasons including providing less spurious radiation from the probe current, in addition to the simplicity in theoretical engineering installation and practical manufacturing. It is well known that the values of the coupling are decreased as the distance separation increased. Cylindrical circular microstrip antenna with resonant frequency operating is 3.5GHz for mode, several parameters like return loss, band width, and input impedance are calculated. Also, for isolated coupling, mutual coupling coefficients, directivity gain, for different separations between the centers of the two adjacent circular patches in terms the wave length operating are calculated. Moreover, the electromagnetic band gap EBG structure is used for reducing the mutual coupling created by the surface waves in order to enhance the antenna's performance in an array has become smaller than before. The proposed EBG is a three triangular-shape equal sides metallic structure, utilizing the inter-element spacing in an array. The less value of for the spacing between the two centers of patches is . BW percentage increased to 34.3% and the directivity is enhanced also. Additionally, simulations were done using MATLAB 2017b.

Lamb waves manipulation by piezoelectric metasurface with tunable diffraction orders

In this paper, a piezoelectric metasurface is proposed to manipulate the anti-symmetric mode Lamb wave by altering the diffraction order. The metasurface attached to a host plate is symmetrically arranged by out-of-plane polarized piezoelectric patches connected with synthetic inductance circuits. Without changing the physical configuration, the transmitted phase of the anti-symmetric mode Lamb wave can be shifted arbitrarily in 0 ∼ 2π range by the metasurface. Furthermore, the relationship between the phase gradient and diffraction order is investigated, and different orders of diffraction waves can be obtained by adjusting the shunting inductance circuits. The symmetric transmission and asymmetric transmission from a couple of axis symmetric incident waves can be realized by utilizing +1st-order and −1st-order diffraction. Moreover, omnidirectional wave reflection and wave trapping in channelized waveguides can also be realized by utilizing the 0th-order diffraction. The results indicate that the proposed piezoelectric metasurface has great potentials in manipulating guided waves with a large incident angle and isolating wave propagation.

An Improved Lifetime and Energy Consumption with Enhanced Clustering in WSNs

A wireless sensor network (WSN) is made up of sensor nodes that communicate via radio waves in order to conduct sensing functions. In WSN, the location of the base station is critical. Although base stations are fixed, they may move in response to data received from sensor nodes under specific conditions. Clustering is a highly efficient approach of minimising energy use. The issues of extending the life of WSNs and optimising their energy consumption have been addressed in this paper. It has been established that integrating mobile sinks into wireless sensor networks extends their longevity. Thus, this research proposes an optimal clustering and routing technique for optimising the energy usage and lifetime of WSNs. To minimise energy consumption, this research employs movable and stationary sink nodes. The K-Medoid clustering model is used to generate the initial number of nodes in the various clusters. After that, the cluster head is chosen using a hybrid Interval Type-2 Fuzzy technique that takes three aspects into account: residual energy, node centrality, and neighbourhood. A highly efficient backup cluster head (CH) collecting system can provide in significant energy savings while also prolonging the system’s life. Finally, better Reinforcement learning combined with a Genetic algorithm routing protocol is used to ensure effective data delivery. The suggested approach’s efficacy is evaluated in comparison to earlier approaches utilising residual node energy, delay or average delay, packet delivery ratio, throughput, network longevity, average energy consumption, and multiple alive nodes. In experiments, the proposed strategy outperforms existing strategies.

Magnetic anisotropy as an evidence of local magnetic moments in paramagnetic phase of Cr-V alloys

Chromium-rich Cr-V alloys exhibit three phases. The paramagnetic phase (P) above Néel temperature (TN), a transverse polarization spin-density-wave (SDW) phase (AF1) below TN and above the spin–flip temperature (TSF), when the longitudinal polarization SDW phase (AF2) is formed. In the paramagnetic phase, Cr exhibit a Pauli susceptibility with weak temperature dependence. Otherwise, the introduction of small amounts of V in Cr not only decreases TN continuously, but also induces a Curie-Weiss behavior (CW) that we associate with local magnetic moments. This behavior is limited up to 0.67%V and magnetic fields of 15 kOe and was also observed for different Cr alloys. The origin of local magnetic moments has been associated with the establishment of local spin-density waves (LSDW) around V impurities. In this work, we presented an investigation of the effects of local magnetic moments in antiferromagnetic phases in Cr-V alloys. The magnetic susceptibility measurements around the spin–flip transition suggest that the local-SDW induces the strong magnetic anisotropy in the long-range order of the spin-density wave as it is revealed in the thermomagnetic results.

Influence of Slot Combination on the Vibration of Low-Noise Asynchronous Motor

The slot combination of stator and rotor plays a decisive role in the tangential force and radial force of the motor, to obtain the influence of slot combination on motor vibration and noise, taking a 55kW asynchronous motor with a maximum speed of 1500 r/min as an example, and four kinds of motors with different slot combination were designed. The order and frequency of electromagnetic force waves with different slot combinations were estimated by numerical method, and the influence of slot combination on the vibration of the motor was studied by test.

Record-Breaking Frequency of 44 GHz Based on the Higher Order Mode of Surface Acoustic Waves with LiNbO3/SiO2/SiC Heterostructures

Surface acoustic wave (SAW) technology has been extensively explored for wireless communication, sensors, microfluidics, photonics, and quantum information processing. However, due to fabrication issues, the frequencies of SAW devices are typically limited to within a few gigahertz, which severely restricts their applications in 5G communication, precision sensing, photonics, and quantum control. To solve this critical problem, we propose a hybrid strategy that integrates a nanomanufacturing process (i.e., nanolithography) with a LiNbO3/SiO2/SiC heterostructure and successfully achieve a record-breaking frequency of about 44 GHz for SAW devices, in addition to large electromechanical coupling coefficients of up to 15.7%. We perform a theoretical analysis and identify the guided higher order wave modes generated on these slow-on-fast SAW platforms. To demonstrate the superior sensing performance of the proposed ultra-high-frequency SAW platforms, we perform micro-mass sensing and obtain an extremely high sensitivity of approximately 33151.9 MHz·mm2·μg−1, which is about 1011 times higher than that of a conventional quartz crystal microbalance (QCM) and about 4000 times higher than that of a conventional SAW device with a frequency of 978 MHz.

Dynamic analysis of the subsea production system with lazy-wave risers attached to FPSO.

The lazy-wave riser is an input and output riser for a flexible development system, which is widely used in all the riser and pipeline systems. Because of the influence of various factors, its configuration description, control and motion which have a strong nonlinear character are complex during the running process of the lazy-wave riser. Reference to the specific structure and environmental parameters of a certain lazy-wave risers system with a 300 thousand tons FPSO, with the basis of the specific process of the flexible riser system at work, the lazy-wave risers were discretized into lumped mass models, combined with AQWA, the simplified dynamic model of the whole system at the depth of 2100m has been established by the large hydrodynamic analysis software OrcaFlex. The dynamic response characteristics of the lazy-wave risers have been given by using time domain coupling method. With and without the consideration of the 2nd wave drift load in the simulation process, the effects of the 2nd wave drift load on the results are obtained. The simulation results reveal the difficulty of simulation convergence caused by a large number of risers and flexible components. The 2nd order wave drift loads have a significant effect on the riser system, resulting in the increasement of the effective tension at each end of each riser. To counteract the magnitude of the FPSO response caused by such loads, the number of mooring lines needed to be increased or combined with dynamic positioning techniques to optimize the design.