المؤلفون: Bilal, Muhammad¹ (AUTHOR), Ren, Jingli¹ (AUTHOR), Alsubaie, A. S. A.² (AUTHOR), Mahmoud, K. H.² (AUTHOR), Inc, Mustafa^3,4,5 (AUTHOR) minc@firat.edu.tr

المصدر: Optical & Quantum Electronics. Jan2024, Vol. 56 Issue 1, p1-23. 23p.

مصطلحات موضوعية: *ION acoustic waves, *ACOUSTIC wave propagation, *THEORY of wave motion, *WATER depth, *NONLINEAR waves, *WATER waves

مستخلص: In this study, we will extract new impressive visions for the exact traveling wave solutions to the Improved Boussinesq dynamical model of water wave problems in a weakly dispersive medium of shallow water or ion acoustic waves under the damping constant of internal friction. In this study, the new extended direct algebraic method has been used to generate some new and more universal exact traveling wave solutions. The recovered solutions are divided into single (kink, anti-kink, singular), bright, dark, complex, and combo forms. During the derivation, new families of hyperbolic, exponential, and periodic wave solutions with arbitrary parameters also emerged. The achieved outcomes are examined using three-dimensional plotline, contour plot, and two-dimensional plotline for definite parametric values. Additionally, the results have been compared with other existing results in the literature to show their uniqueness. Moreover, the findings show that the method taken is successful, simple, and can be use even to complicated phenomena, and this work will also be helpful to a large number of engineering model specialists and in many other areas of physics. [ABSTRACT FROM AUTHOR]

المؤلفون: Derteev, S. B.¹ (AUTHOR) derteevsergei@mail.ru, Sapraliev, M. E.¹ (AUTHOR), Bembitov, D. B.¹ (AUTHOR), Mikhalyaev, B. B.¹ (AUTHOR)

المصدر: Geomagnetism & Aeronomy. Dec2023, Vol. 63 Issue 8, p1313-1317. 5p.

مصطلحات موضوعية: *PLASMA waves, *ACOUSTIC wave propagation, *PLASMA oscillations, *LONGITUDINAL waves, *PLASMA temperature, *DATA compression

مستخلص: The influence of the effects of thermal conduction and heating/radiative losses on the propagation of acoustic waves in a rarefied high-temperature plasma is studied. A constant heating function is chosen, and an interpolation is used for the radiative-loss function, which is based on the values found by the CHIANTI 10 code. Waves are analyzed in a linear approximation based on the dispersion relation. The input parameters in the problem are the plasma temperature and density and the output parameters are the period of oscillations and their damping time. Conversely, having observational data on compression waves, one can pose the problem of finding the parameters of the coronal plasma from the oscillation parameters. The situations in which the effect of the misbalance between heating and losses can, along with thermal conductivity, play a significant role in wave damping are shown. The temperature ranges at which instability and aperiodic damping of acoustic oscillations are possible are determined. [ABSTRACT FROM AUTHOR]

المؤلفون: Shahriar, Adnan¹ (AUTHOR) adnan.shahriar@utsa.edu, Mostafa, Ahmed Jenan¹ (AUTHOR)

المصدر: Mathematics (2227-7390). Dec2023, Vol. 11 Issue 24, p4954. 16p.

مصطلحات موضوعية: *TRANSITION metals, *ACOUSTIC wave propagation, *DERIVATIVES (Mathematics), *IMPACT loads

مستخلص: Wave propagation or acoustic emission waves caused by impact load can be simulated using the finite element (FE) method with a refined high-fidelity mesh near the impact location. This paper presents a method to refine a 3D finite element mesh by increasing the polynomial order near the impact location. Transition elements are required for such a refinement operation. Three protocols are defined to implement the transition elements within the low-order FE mesh. Due to the difficulty of formulating shape functions and verification, there are no transition elements beyond order two in the current literature for 3D elements. This paper develops a complete set of transition elements that facilitate the transition from first- to fourth-order Lagrangian elements, which facilitates mesh refinement following the protocols. The shape functions are computed and verified, and the interelement compatibility conditions are checked for each element case. The integration quadratures and shape function derivative matrices are also computed and made readily available for FE users. Finally, two examples are presented to illustrate the applicability of this method. [ABSTRACT FROM AUTHOR]

المؤلفون: Roknujjaman, Md.¹ (AUTHOR) roknujjaman.md.ka@un.tsukuba.ac.jp, Kyotoh, Harumichi¹ (AUTHOR), Yohei, Asada² (AUTHOR), Yasuhisa, Adachi² (AUTHOR)

المصدر: Physics of Fluids. Dec2023, Vol. 35 Issue 12, p1-10. 10p.

مصطلحات موضوعية: *ELASTIC wave propagation, *PULSATILE flow, *THEORY of wave motion, *TWO-dimensional models

مستخلص: The objective of this study was to comprehensively examine the pulsatile flow behavior within an elastic tube using experimental and theoretical approaches. This work is an extension of our earlier report [Roknujjaman et al., Phys. Fluids, 34, 123612 (2022)]. In this paper, we adapted a quasi-one-dimensional model to elucidate the wave propagation and pulse attenuation phenomena in an elastic tube and compared with experimental findings. According to our investigation, the key findings were as follows: the experimental and predicted flow wave propagation trend agreed well. Additionally, because of the silicon tubes greater deformation than the urethane tubes, the pulsation was decreased farther in the silicon tubes than in the urethane ones. Furthermore, because of the reflected wave near the tube exit, the pulsations amplitude significantly increased, but it did not enlarge when the resistance was installed at the exit. Finally, we infer that the quasi-one-dimensional model is a better fit for experimental results compared to the two-dimensional model. [ABSTRACT FROM AUTHOR]

العنوان البديل: Imagistica GPR – tehnică geofizică de înaltă rezoluție pentru cercetare interdisciplinară.

المؤلفون: Constantina, FILIPCIUC¹ tatiana0906@yahoo.com, Elena, TUDOR¹ gt_elena2004@yahoo.com, Irina, STOIAN¹ airinsweety@yahoo.com, Ovidiu, AVRAM¹ ovi.exe75@gmail.com, Ioan, SCUTELNICU¹ ulmeanuantonio@yahoo.com, Antonio, ULMEANU¹ pinklloyd73@yahoo.com, Gabriel, TĂTARU Adrian¹ adriantataru@live.com, Luminița, DINU¹ luminita_iancu84@yahoo.com

المصدر: Oltenia, Studii si Comunicari Seria Stiintele Naturii. Dec2023, Vol. 39 Issue 2, p36-43. 8p.

مصطلحات موضوعية: *LANDSLIDE hazard analysis, *ELECTROMAGNETIC wave propagation, *GPS receivers, *ARCHAEOLOGICAL excavations, *INTERDISCIPLINARY research, *LANDSLIDES

مصطلحات جغرافية: ROMANIA

الملخص (بالإنجليزية): The geohazard team at the Geological Institute of Romania works in hazard estimation for land instability phenomena (landslides), in the field of archaeology and in the development of landslide hazard maps. To collect useful data, and thus to provide notable research, the team uses geophysical electrometry equipment, 3D Laser terrestrial scanner, high-precision GPS receivers and a GPR system. In this paper we will refer to the use of the GPR system in the field of archaeology. Being a method of prospecting/geophysical investigation of the subsoil based on the study of the propagation of electromagnetic waves with frequencies of the order of MHz or GHz, georadar records the dielectric permittivity contrasts in the subsoil. The method is considered to be fast, because it can be covered daily from 1.5 km of profile in the case of geological applications and up to 70-80 km in the case of investigations on roads or railways. The technique is non-destructive, the transmitter and receiver assembly are not affecting the investigated environment in any way. The digital analogue acquisition of the GPR system allows quasi-continuous measurements, the “in situ” highlighting of buried structures and the rapid processing of the obtained records. In recent decades, it has become apparent that GPR and other geophysical methods can really help in probing archaeological sites at fairly large investigation depths in a nondestructive manner. [ABSTRACT FROM AUTHOR]

Abstract (Romanian): Echipa de geohazard a Institutului Geologic din România lucrează în estimarea hazardului pentru fenomene de instabilitate a terenului (alunecări de teren), în domeniul arheologiei și, de asemenea, în elaborarea hărților de hazard la alunecări de teren. Pentru a colecta date utile, și pentru a oferi astfel o cercetare notabilă, echipa folosește echipamente de electrometrie, scaner terestru Laser 3D, receptoare GPS de înaltă precizie și un sistem GPR. În această lucrare ne vom referi la utilizarea sistemului GPR în domeniul arheologiei. Fiind o metodă de prospectare/investigare geofizică a subsolului bazată pe studiul propagării undelor electromagnetice cu frecvențe de ordinul MHz sau GHz, georadarul înregistrează contrastele de permitivitate dielectrică din subsol. Metoda este considerată rapidă, deoarece poate fi parcurs zilnic de la 1,5 km de profil în cazul aplicațiilor geologice și până la 70-80 km în cazul investigațiilor pe drumuri sau căi ferate. Tehnica este nedistructivă, ansamblul emițătorului și receptorului nu afectează în niciun fel mediul investigat. Achiziția digitală analogică a sistemului GPR permite măsurători cvasi-continue, evidențierea „in situ” a structurilor îngropate și prelucrarea rapidă a înregistrărilor obținute. În ultimele decenii, a devenit evident că GPR-ul și alte metode geofizice pot ajuta cu adevărat la sondarea siturilor arheologice la adâncimi de investigare destul de mari într-o manieră nedistructivă. [ABSTRACT FROM AUTHOR]

المؤلفون: Ba, Jing¹ (AUTHOR), Fang, Zhijian¹ (AUTHOR) fzj2022@hhu.edu.cn, Fu, Li-Yun² (AUTHOR), Xu, Wenhao¹ (AUTHOR), Zhang, Lin¹ (AUTHOR)

المصدر: Geophysical Journal International. Dec2023, Vol. 235 Issue 3, p2056-2077. 22p.

مصطلحات موضوعية: *ACOUSTIC wave propagation, *NON-Newtonian fluids, *POROUS materials, *THEORY of wave motion, *GEOPHYSICAL prospecting, *OPTICAL dispersion

مستخلص: Wave propagation in anelastic rocks is a relevant scientific topic in basic research with applications in exploration geophysics. The classical Biot theory laid the foundation for wave propagation in porous media composed of a solid frame and a saturating fluid, whose constitutive relations are linear. However, reservoir rocks may have a high-viscosity fluid, which exhibits a non-Newtonian (nN) behaviour. We develop a poroelasticity theory, where the fluid stress-strain relation is described with a Kelvin–Voigt mechanical model, thus incorporating viscoelasticity. First, we obtain the differential equations from first principles by defining the strain and kinetic energies and the dissipation function. We perform a plane-wave analysis to obtain the wave velocity and attenuation. The validity of the theory is demonstrated with three examples, namely, considering a porous solid saturated with a nN pore fluid, a nN fluid containing solid inclusions and a pure nN fluid. The analysis shows that the fluid may cause a negative velocity dispersion of the fast P (S)-wave velocities, that is velocity decreases with frequency. In acoustics, velocity increases with frequency (anomalous dispersion in optics). Furthermore, the fluid viscoelasticity has not a relevant effect on the wave responses observed in conventional field and laboratory tests. A comparison with previous theories supports the validity of the theory, which is useful to analyse wave propagation in a porous medium saturated with a fluid of high viscosity. [ABSTRACT FROM AUTHOR]

المؤلفون: Zhao, Wusheng¹ (AUTHOR) wszhao@whrsm.ac.cn, Qin, Changkun² (AUTHOR) 1280183931@qq.com, Chen, Weizhong³ (AUTHOR) wzchen@whrsm.ac.cn, Tan, Xianjun³ (AUTHOR) xjtan@whrsm.ac.cn

المصدر: International Journal of Geomechanics. Dec2023, Vol. 23 Issue 12, p1-12. 12p.

مصطلحات موضوعية: *ELASTIC wave propagation, *MODEL airplanes, *STRESS waves, *ELASTIC waves, *SEISMIC waves, *ADHESIVES, *THEORY of wave motion

مستخلص: Wave propagation in a layered rock mass is a common problem in geotechnical engineering. The bedding planes in a layered rock mass are generally in situ stressed and adhesively bonded. This study extended the time-domain recursive method to analyze the wave propagation in a layered rock mass with adhesive bedding planes. The maximum stress criterion was used to indicate the adhesive failure of bedding planes. The Bandis–Barton and Coulomb slip models were used to characterize the normal and tangential behaviors of bedding planes after the adhesive bond fails. Based on the backward differentiation formula, an analytical solution reflecting four possible states of the bedding plane and the in situ stresses in rock mass was established. Subsequently, the solution was verified for various conditions. Besides, parametric studies were carried out to assess the influences of adhesive properties of bedding planes and in situ stresses on wave transmission. The transmission coefficient of seismic waves increases linearly as the adhesive strength of the bedding plane increases. The in situ normal stress could facilitate wave transmission across the bedding plane, while the in situ shear stress causes the direction-dependency of transmitted waves. Furthermore, the impacts of bedding plane adhesion and in situ stresses on wave propagation were influenced by the amplitude, frequency, and impinging angle of incident waves. The welded model that ignores the adhesion failure of the bedding plane and the unbonded models that neglect the interface adhesion could overestimate or underestimate the transmitted wave across a bedding plane. [ABSTRACT FROM AUTHOR]

المؤلفون: He, Guojin¹ (AUTHOR), Ji, Shengyun² (AUTHOR), Wu, Rongjun³ (AUTHOR), Yu, Qiao⁴ (AUTHOR), Liu, Yanan¹ (AUTHOR), Shi, Yafei^2,4 (AUTHOR) shiyafei@tju.edu.cn, Li, Na¹ (AUTHOR) shiyafei@tju.edu.cn

المصدر: Atmosphere. Dec2023, Vol. 14 Issue 12, p1728. 14p.

مصطلحات موضوعية: *RADIO wave propagation, *TELECOMMUNICATION, *MILITARY electronics

مستخلص: In the field of electronic communication warfare, accurately predicting the range and intensity of shortwave interference signals presents a significant challenge due to the complex interplay between the ionospheric parameters and the electromagnetic environment. To address this challenge, we designed a novel tool to assess the interference impact area of shortwave interference signals in a dynamically changing ionospheric environment. Considering sophisticated ionospheric radio wave propagation models and innovative spatial grid methods, this tool finishes the comprehensive spatial distribution of the interference impact area and delivers grid-based insights into the interference intensity. Furthermore, the test verification of the tool demonstrated a mean error of 8.42 dB between the measured and simulated results, underscoring the efficacy and reliability of this tool. This pioneering work is poised to make substantial contributions to the field of communication electronic warfare and holds significant promise for guiding the development of interference countermeasures. [ABSTRACT FROM AUTHOR]

المؤلفون: Bibi, Farhat¹ (AUTHOR), Ali, Hashmat² (AUTHOR), Azhar, Ehtsham¹ (AUTHOR) ehtsham@uaar.edu.pk, Jamal, Muhammad¹ (AUTHOR), Ahmed, Iftikhar^2,3 (AUTHOR), Ragab, Adham E.⁴ (AUTHOR)

المصدر: Scientific Reports. 11/20/2023, Vol. 13 Issue 1, p1-20. 20p.

مصطلحات موضوعية: *ELASTIC waves, *ELASTIC wave propagation, *POROUS materials, *SHEAR waves, *THEORY of wave motion, *REFLECTANCE

مصطلحات جغرافية: SCHWABISCH Hall (Germany)

People: HELMHOLTZ, Hermann von, 1821-1894

مستخلص: This investigation relates to the research on Hall current on propagation and reflection of elastic waves through non-local fractional-order thermoelastic rotating medium with voids. The system is split up into longitudinal and transverse components using the Helmholtz vector rule. It is observed that, through the frequency dispersion relation four coupled quasi-waves exist in the medium. The rotating solid modifies the nature of purely longitudinal and transverse waves toward the quasi-type waves. All the propagating waves are dispersive as they depend upon angular frequency. The quasi-longitudinal wave qP and quasi-transverse wave qSV faces cut-off frequencies. The nonlocal parameter affect all the waves except the quasi void wave. Analytically, the reflection coefficients of the wave are computed using suitable boundary conditions. MATLAB software is used to perform numerical computations for a chosen solid material. The amplitude ratios and the speed of propagation of the wave are plotted graphically for rotational frequency, nonlocal, fractional order, and Hall current parameter. The significant effect of the physical parameters on the computed results has been observed. The cut-off frequency of the waves is also presented graphically. The energy conservation law is proved in the form of energy ratios. The earlier findings in the literature are obtained as special case in the absence of rotation, Hall current parameter and porous voids. [ABSTRACT FROM AUTHOR]

المؤلفون: Almawgani, Abdulkarem H. M.¹ (AUTHOR) ahalmawgani@nu.edu.sa, Fathy, Hamza Makhlouf² (AUTHOR), Elsayed, Hussein A.² (AUTHOR), Abdelrahman Ali, Yahya Ali³ (AUTHOR), Mehaney, Ahmed² (AUTHOR) ahmed0111236@science.bsu.edu.eg

المصدر: Scientific Reports. 11/18/2023, Vol. 13 Issue 1, p1-18. 18p.

مصطلحات موضوعية: *FANO resonance, *ACOUSTIC wave propagation, *PHONONIC crystals, *TRANSFER matrix, *TEMPERATURE effect, *QUALITY factor

مستخلص: Detecting of the levels of greenhouse gases in the air with high precision and low cost is a very urgent demand for environmental protection. Phononic crystals (PnCs) represent a novel sensor technology, particularly for high-performance sensing applications. This study has been conducted by using two PnC designs (periodic and quasi-periodic) to detect the CO2 pollution in the surrounding air through a wide range of concentrations (0–100%) and temperatures (0–180 °C). The detection process is physically dependent on the displacement of Fano resonance modes. The performance of the sensor is demonstrated for the periodic and Fibonacci quasi-periodic (S3 and S4 sequences) structures. In this regard, the numerical findings revealed that the periodic PnC provides a better performance than the quasi-periodic one with a sensitivity of 31.5 MHz, the quality factor (Q), along with a figure of merit (FOM) of 280 and 95, respectively. In addition, the temperature effects on the Fano resonance mode position were examined. The results showed a pronounced temperature sensitivity with a value of 13.4 MHz/°C through a temperature range of 0–60 °C. The transfer matrix approach has been utilized for modeling the acoustic wave propagation through each PnC design. Accordingly, the proposed sensor has the potential to be implemented in many industrial and biomedical applications as it can be used as a monitor for other greenhouse gases. [ABSTRACT FROM AUTHOR]