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The paper investigates the role of solid solution strengthening on the shock wave structure and Hugoniot elastic limit (HEL) in [111] copper crystals by molecular dynamics. Cu–Ni, Cu–Zn, Cu–Ag, and Cu–Al solid solutions are chosen to cover the range of atomic size misfit parameters for the solute atoms. The results show that in crystals with dislocations, the HEL decays slower with an increase in the misfit parameter of the solute, resulting in higher HEL values at a certain shock propagation distance. The Cu–Al solid solutions with the largest misfit parameter exhibit the largest deceleration of HEL decay. When the concentration of Al atoms increases to 20 at. %, the HEL almost does not change with shock propagation distance and a plateau shape of the elastic precursor is observed, as in the case of perfect crystals. In solid solutions without dislocations, the elastic precursor forms at lower velocities compared with perfect copper crystals, except for the Cu–20 at. % Ni solid solution. The HEL values increase with increasing misfit parameters and may take values lower than that for pure copper. These results show that the formation of the elastic precursor is facilitated by the presence of solid solution atoms, but the HEL magnitude and decay exponent are related to dislocation mobility in [111] copper crystals. [ABSTRACT FROM AUTHOR]

Isotropic materials are required to adhere to various mechanical principles due to their limited thermal stability. For instance, it is essential for Poisson's ratio to be within the range of −1 to 0.5, and the longitudinal wave velocity must exceed the transverse wave velocity. Nevertheless, perfect crystals, as anisotropic materials, have the ability to defy conventional rules. Through the integration of high-throughput processes and first-principles calculations, a comprehensive exploration of known materials was conducted, resulting in the establishment of a database featuring an extreme anisotropic mechanism. This included the identification of abnormal Poisson's ratios (with the directional Poisson's ratio ranging from −3.00 to 3.67), the discovery of extreme negative linear compressibility, the determination of the upper and lower limits of the sound velocity, and other associated properties. Several materials with abnormal Poisson's ratios (<−1 or >0.5) were listed, and their peculiar mechanical behavior, wherein the volume decreased counterintuitively with uniaxial tension, was discussed. Finally, this study focused on the velocities of longitudinal and transverse waves, with specific emphasis on materials exhibiting transverse wave velocities that exceeded the longitudinal wave velocities. [ABSTRACT FROM AUTHOR]

Recently, the mode conversion of elastic waves has attracted much attention, due to its scientific significance and potential applications. The applications based on the high mode conversion efficiency were also explored in many fields. However, because of the complexity of elastic waves, the existing structures for the high efficient conversion of elastic waves are relatively complicated, and there are also some limitations in the practical design. Here, we report the extraordinary mode conversion of elastic waves through asymmetric brass plates partitioned by subwavelength cuts. It is demonstrated that high efficiencies (90%) and one-way conversions between transversal waves and longitudinal waves are achieved by the structured solid plate at the resonant frequency, which leads to the striking unidirectional transmission of elastic waves. Analyzing the resonant fields demonstrates that the intrinsic modes within the individual pieces derived by the cuts are responsible for this abnormal wave conversion. The simple scheme for wave conversion presented here may have potential applications, such as non-invasive flow sensing. [ABSTRACT FROM AUTHOR]

This study illustrates the successful achievement of tunable defect bands in one-dimensional defective phononic crystals (PnCs) through the incorporation of piezoelectric defects with synthetic negative capacitances (SNCs) for the first time. The efficacy of SNCs in creating tunable bandpass filters across a broad frequency range is thoroughly examined using the proposed analytical and numerical models. A newly developed electroelastically coupled transfer matrix that incorporates SNCs is presented, considering either series or parallel connection between bimorph piezoelectric elements. Defect band and transmittance analyses are conducted using the transfer matrix and S-parameter methods. Two key findings emerge from this investigation. First, when the total equivalent capacitance of the bimorph piezoelectric elements and SNC becomes zero, the defect band representing the point-symmetric defect-mode shape can be customized throughout the entire phononic bandgap. Second, the constant transmittance value, resembling short-circuit conditions, highlights the remarkable ability of SNCs to tune defect bands without energy dissipation, paving the way for fully tunable bandpass filters. To propel this research forward, future investigations could explore expanding the design space with double defects, adopting enhanced modeling techniques to account for lateral and shear effects, developing a control algorithm for the automatic optimization of SNC values in actively tunable bandpass filters, and incorporating artificial intelligence into design methods for piezoelectric defects with electrical connections. [ABSTRACT FROM AUTHOR]

This paper presents the design of a single-phase solid phononic crystal (PnC) structure featuring a regular hexagonal perforation pattern. The structure manifests three negative refraction bands, encompassing one for transverse waves and two for longitudinal waves, thereby enabling simultaneous control of shear and longitudinal waves. Due to the high symmetry of the triangular lattice, the equal frequency curves corresponding to the negative refraction band approach circular shapes, suggesting a nearly isotropic negative refraction effect. This negative refraction effect is achieved through specific mass resonance modes closely related to the porous structure designed in this paper. Initially, we analyze the band structure of the PnC, followed by designing the PnC plate structure to achieve negative refraction control for transverse waves at a frequency of 32.4 kHz, with a negative refraction index of −1. Additionally, negative refraction control for longitudinal waves is attained at frequencies of 44 and 64.54 kHz. Subsequently, we scrutinize the influence of various conditions on negative refraction, including different structural parameters, incident angles, and operating frequencies, while verifying the robustness of the designed phonon crystal structure. Leveraging the negative refraction characteristics of the structure, we construct an elastic wave lens to achieve perfect imaging of shear and longitudinal waves. Finally, employing finite element simulation and analyzing focusing imaging characteristics with different source positions, we validate that the results closely align with theoretical expectations. The solid PnC structure designed in this study holds significant potential for applications in the fields of elastic wave imaging. [ABSTRACT FROM AUTHOR]

Mode coupling and conversion between longitudinal and transverse modes are ubiquitous and universal in elastic waves, presenting a challenge in realistic applications such as nondestructive evaluation and geological exploration, where independent and separate manipulation of each mode is demanded. In this article, we propose a design of elastic metalens that can realize a high-efficiency focusing for the longitudinal wave and a V-shaped converging pattern for the transverse wave at the same time. The metalens is constructed from a metagrating, where each meta-atom has a simple configuration and renders high diffraction efficiency even for large steering angles, enabled by concurrent utilization of grating diffraction theory and advanced optimization algorithms. Interestingly, an arbitrary energy splitting ratio between the reflected longitudinal and transverse waves can be obtained by precisely controlling the coupling strength and conversion efficiency between them, providing improved flexibility and adaptability to various application environments. Two illustrative examples with a sharp focusing effect and tailored conversion efficiency are explicitly demonstrated, with a 50/50 energy splitting ratio between the longitudinal and transverse waves in the first case, and a 70/30 ratio in the second one. [ABSTRACT FROM AUTHOR]

This research problem is an investigation of reflection amplitude in a nonlocal porous-thermo-micropolar diffusion half-space under memory dependent derivative (MDD) thermo-elasticity subjected to impedance boundary reflecting surface. The governing equations for nonlocal porous-thermo-micropolar diffusion medium in MDD theory are formulated. This research challenge is solved analytically for a two-dimensional model in order to demonstrate the presence of four coupled longitudinal waves and two paired transverse waves denoted as coupled longitudinal displacement wave ( cLDW − I ), coupled longitudinal thermal wave ( cLDW − II ), coupled longitudinal mass diffusion wave ( cLDW − III ), coupled longitudinal void volume fraction wave ( cLDW − IV ), and coupled transverse displacement wave ( cTDW ) and coupled transverse micro-rotational wave ( cTMW ). When there is nonlocality, diffusion, and porous characteristics in the medium, it is discovered to have an impact on these coupled longitudinal waves, making them dispersive and attenuating. The transverse wave is non-attenuating but dispersive, it is unaffected by diffusion and porous characteristics. To find the expression for the reflection coefficients of reflected waves, the plane wave reflection from a thermally insulated surface subjected to an impedance boundary is explored. For a specific material, the reflection coefficients of the reflected waves are calculated, and graphic representations of the fluctuations of the reflection coefficients versus the incidence angle, nonlocality, diffusion and porous constants are provided. For further investigation, energy ratio can be studied in future. [ABSTRACT FROM AUTHOR]

Shear waves in underground longitudinal structures impose deformations that need to be accounted for in structural design. Simplified approaches for such structures typically consider the Winkler foundation model, assuming Euler-Bernoulli beam theory, which neglects shearing-induced distortions, especially significant when shear waves are a dominant component of the seismic motion. In order to overcome these limitations, Timoshenko beam models have been proposed in the literature. These approaches however depend on an appropriate determination of the ground springs. Existing analytical formulations often assume plane-strain conditions, inadequate for representing low frequencies and thus are not directly applicable for pseudo-static interaction analyses. The present paper develops analytical solutions to determine transverse and rotation Winkler springs for structures subjected shear waves. The proposed springs overcome the drawbacks of plane-strain models and can be construed as a generalisation of them. The springs are obtained as a function of the seismic wavelength and the ground-structure stiffness contrast. Results obtained are validated against solutions from the literature and numerical results from a full 3D finite-element model. A non-dimensional parametric study is also presented, that allow an expedited evaluation of ground springs for practical applications. [ABSTRACT FROM AUTHOR]

Estimation of the porosity of a hydrate reservoir is essential for its exploration and development. However, the estimation accuracy was usually less certain in most previous studies that simply assumed that there is a linear relationship between the porosity and single‐elastic wave velocities or other rock physical parameters, thus affecting the evaluation of the reserves. In the three‐phase Biot‐type equations that are fundamental to model a hydrate‐bearing reservoir, porosity, alongside hydrate saturation, mineral constituent proportions and hydrate–grain contact factor, is non‐linearly responded by density, compressional and shear wave velocities. To improve porosity estimation, we propose to invert simultaneously four‐parameter (porosity, hydrate saturation, mineral constituent proportions and hydrate–grain contact factor) using an iteratively nonlinear interior‐point optimization algorithm to solve a nonlinear objective function that is a summation of the squared misfits between the well log and three‐phase Biot‐type equation–modelled density, compressional and shear wave velocities. A test in Mount Elbert gas hydrate research well was conducted for the case of a gas hydrate stratigraphic test well where elastic wave velocities, density, porosity and mineral composition analysis data are available. The four‐parameter inversion yielded a lower root mean square error for porosity (0.0245) across the entire well‐logging section compared to previous estimations from the linear relationship, post‐stacked and pre‐stacked seismic traces as well as the pore‐filling effective medium theory model applied to other well cases. Additionally, the other three parameters demonstrated good agreement with well logs. Inversion tests conducted at three additional hydrate sites also produced accurate results. Consequently, the new method surpasses previous approaches in porosity estimation accuracy. [ABSTRACT FROM AUTHOR]

Background and aims Design Setting Participants Measurements Findings Conclusions Research demonstrates that siblings, especially older siblings, make unique contributions to adolescents' substance use above and beyond shared genetics and shared parenting. Older siblings' influences on younger adolescent siblings' alcohol use operate through both direct and indirect pathways. Using three waves of longitudinal data, the present study tested an integrated model of sibling influence processes focused on the linkages between older adolescent siblings' earlier alcohol use and younger adolescent siblings' later alcohol use.Longitudinal study using data collected from families on three occasions: Time 1 (March 2019–February 2020), Time 2 (July 2020–February 2021) and Time 3 (November 2021–February 2022) via online surveys.Families resided in five midwestern states in the US (Illinois, Indiana, Ohio, Pennsylvania and Wisconsin).Participants included two adolescent‐aged siblings and one parent from 682 families (n = 2046 persons).Alcohol use by adolescents and parents was assessed at Time 1; younger siblings' social alcohol expectancies and perceptions of modeling were measured at Time 2; and younger siblings' alcohol use was measured at Time 3.Older siblings' earlier alcohol use predicted younger siblings' later drinking both directly [b = 0.15, standard error (SE) = 0.04, β = 0.17, P < 0.001] and indirectly through younger siblings' social alcohol expectancies [δ = 0.02, SE = 0.008, 95% confidence interval (CI) = 0.003, 0.03]. The direct (δ = −0.14, SE = 0.07, 95% CI = −0.27, −0.01) and indirect (δ = 0.03, SE = 0.02, 95% CI = 0.0001, 0.06) links were further moderated by younger siblings' reports of sibling modeling, but not by gender composition of the sibling dyad or the interaction of modeling and gender composition.Older siblings' alcohol use appears to influence younger siblings' later alcohol use directly, as well as indirectly through younger siblings' expectancies about alcohol. The global context of the sibling relationship, in this case sibling modeling, may further amplify or dampen these pathways of influence. [ABSTRACT FROM AUTHOR]

This study designs a blasting loading device capable of changing the utilization of explosive gas by modifying the constraint conditions. The propagation of crack and stress waves in red sandstone under different explosive gases is recorded using digital image correlation technology and ultra‐dynamic strain gauges. Both methods are effectively validated against each other. The results showed that as the utilization of explosive gas increases, the explosive stress wave induces layer cracking at the specimen's far end and tensile failure at its near end. In addition, the larger the stress wave's amplitude, the greater the spatial attenuation coefficients of the compression and tension waves. The study ultimately deduces the propagation process of the incident wave and analyzes the influence of stress wave propagation on the specimen's failure characteristics. [ABSTRACT FROM AUTHOR]

AbstractThe present work is implicated with the investigation of wave propagation in a homogeneous, isotropic, non-local microelongated viscothermoelastic solid half space with variable thermal conductivity under the dual phase lag (DPL) model. It is found analytically that three coupled longitudinal waves and one independent transverse wave exist in the medium which travel with distinct speeds. Reflection coefficients and energy ratios of various reflected waves are obtained analytically and presented graphically for aluminum epoxy-like material. The variations of these reflection coefficients are analyzed for different values of non-local parameter, microelongational parameter, viscosity and variable thermal conductivity. The expressions of energy ratios acquired in explicit form are also represented graphically as functions of the angle of incidence in accordance with the defined rule of conservation of energy. [ABSTRACT FROM AUTHOR]

The spatial misrepresentation objection (SMO) against the wave theory of sound argues that if sounds are compression waves, then our auditory experiences are massively illusory for not representing sounds as propagating in the medium. Thus, it claims that the wave theory should be rejected because it is unreasonable to accept such an error theory of hearing. This paper presents a metaphysics of compression waves to show that the wave theory correctly implies that we cannot hear sounds as propagating. Moreover, I argue that the SMO is based on a mischaracterisation of the phenomenology of auditory experiences. A new conception of auditory perception is then proposed to explain how a sound source and its compression wave are both represented in the same auditory experience. Finally, I compare my view with some alternative theories of sound. Overall, it is found that the SMO is more of an objection against the traditional conception of hearing than a challenge to the wave theory of sound. [ABSTRACT FROM AUTHOR]

To solve the problem of low broadband multi-directional vibration control of fluid-conveying pipes, a novel metamaterial periodic structure with multi-directional wide bandgaps is proposed. First, an integrated design method is proposed for the longitudinal and transverse wave control of fluid-conveying pipes, and a novel periodic structure unit model is constructed for vibration reduction. Based on the bandgap vibration reduction mechanism of the acoustic metamaterial periodic structure, the material parameters, structural parameters, and the arrangement interval of the periodic structure unit are optimized. The finite element method (FEM) is used to predict the vibration transmission characteristics of the fluid-conveying pipe installed with the vibration reduction periodic structure. Then, the wave/spectrum element method (WSEM) and experimental test are used to verify the calculated results above. Lastly, the vibration attenuation characteristics of the structure under different conditions, such as rubber material parameters, mass ring material, and fluid-structure coupling effect, are analyzed. The results show that the structure can produce a complete bandgap of 46 Hz–75 Hz in the low-frequency band below 100 Hz, which can effectively suppress the low broadband vibration of the fluid-conveying pipe. In addition, a high damping rubber material is used in the design of the periodic structure unit, which realizes the effective suppression of each formant peak of the pipe, and improves the vibration reduction effect of the fluid-conveying pipe. Meanwhile, the structure has the effect of suppressing both bending vibration and longitudinal vibration, and effectively inhibits the transmission of transverse waves and longitudinal waves in the pipe. The research results provide a reference for the application of acoustic metamaterials in the multi-directional vibration control of fluid-conveying pipes. [ABSTRACT FROM AUTHOR]

The present article is concerned with the reflection of plane harmonic waves in a nonlocal micropolar thermoelastic medium having void pores in the context of dual-phase-lag and Lord-Shulman models. Two sets of coupled shear waves and three sets of coupled longitudinal waves are shown to exist. When a coupled longitudinal displacement wave is made incident, the reflection coefficients of the various reflected waves and their respective energy ratios are computed analytically and the numerical computation is carried out with the help of MATLAB software. For a particular model, the influence of nonlocal, voids and micropolar parameters on the variations of reflection coefficients and energy ratios of various reflected waves is presented graphically. It is verified that during reflection phenomenon, the sum of energy ratios is equal to unity at each angle of incidence. A comparison between the dual-phase-lag model and Lord-Shulman model is also depicted graphically. [ABSTRACT FROM AUTHOR]

Unmanned aerial vehicles (UAV) on Mars operate in a thin atmosphere of carbon dioxide, where the flow Reynolds number and local sound velocity are significantly reduced compared to the Earth's atmosphere because of low gas density and temperature. Therefore, a Mars UAV with a rotary-wing design can operate in a state of low-Reynolds number (Re = 1-5 × 104) and transonic flow (Ma tip = 0.7–1.2), where flow separation and shock waves occur simultaneously. The interaction between flow separation and shock waves not only makes the entire flow field more complex but also seriously affects the aerodynamic performance of the airfoil, thereby reducing the payload of UAVs, which previous aircraft designs based on the thick atmospheric environment of the Earth have not considered. Therefore, in this study, a numerical simulation method is used to conduct airfoil optimization research on a characteristic airfoil under low-Reynolds number transonic flow (Re = 33200, Ma = 0.85) conditions to acquire additional insight, improve aerodynamic performance of the airfoil, and enhance the payload. The results were compared with the optimization results of subsonic flow (Re = 19500, Ma = 0.50). The Hicks-Henne bump functions method was selected for airfoil parameterization, and non-dominated sorting genetic algorithms (NSGA)-Ⅱ were used for optimization. Through an analysis of the pressure coefficient (C p), surface friction coefficient (C f), and density gradient, the number and intensity of oblique shock waves on the upper and lower surfaces were observed to significantly affect the aerodynamic performance of airfoils under low-Reynolds number flow. The changes in flow separation and transition positions do not directly affect the aerodynamic performance but weaken the oblique shock wave intensity induced by the separation point or directly transform strong shock waves into weaker compression waves because of the absence of flow separation. The optimization results for both subsonic and transonic flow point to a thinner overall shape with a flatter surface with the drag greatly reduced due to the disappearance of shock waves on the lower surface, which significantly improves aerodynamic performance. Compared with the original airfoil, at Ma = 0.85, this design can increase the lift coefficient (C l) by at least 124 % and lift drag ratio (C l /C d) by 177 %. • Aerodynamics issues at low Reynolds numbers and transonic in the Martian environment. • Complex wave system issues occurring at low Reynolds numbers. • Numerical simulation and optimization of airfoil design for Mars Unmanned aerial vehicles. [ABSTRACT FROM AUTHOR]

The effects of phase shift (δ) between compression and shear waves, and consolidation stress ratio (Kc) on the liquefaction resistance of sand under simultaneous compression and shear wave loading is investigated using a hollow cylinder torsional shear apparatus. The differences caused by prior stress history (assessed using drained versus undrained preshear) highlight the importance of test protocols in undertaking research to explore the effects of complex dynamic loading paths. The liquefaction resistance of sand was highly dependent on the loading path. However, it was not affected much by variations in δ , if the horizontal shear stress ratio (τzθ/σmc′) and the ratio between shear stress increment and normal stress increment (ΔS/ΔN) were held constant. In tests with constant cyclic stress ratio (CSR), an increase in δ decreases the cyclic resistance because the increase in δ causes a reduction in the rate of deviatoric stress increment per degree of principal stress rotation. At a given CSR , for δ≠0 cases, a change in ΔS/ΔN does not affect the liquefaction resistance of sand because the magnitude and pattern of rotation is not affected much by ΔS/ΔN (for the ratios explored in this research). Increasing Kc or static shear stress ratio (αst) increased the cyclic resistance of the tested sand for ΔS/ΔN<1. The rate of increase in cyclic resistance with increasing αst decreases with the increase in ΔS/ΔN and was essentially unchanged for ΔS/ΔN=1. This observation, that the rate of increase in cyclic resistance with αst decreases with increasing ΔS/ΔN , is consistent with the observation in the literature that the cyclic triaxial loading yields higher static shear stress correction factor (Kα) than cyclic simple shear in loose sand. [ABSTRACT FROM AUTHOR]

• Curvature generated the stopbands and passbands for the wave propagation. • Wave attenuated at stopbands and propagates at passbands. • Damping caused wave attenuation and affected the frequencies of stopbands and passbands. Understanding the wave propagation is crucial for dynamic analysis of long elastic cables prone to high-order vibrations. The coupling of elastic waves in cables is still not sufficiently understood. However, wave coupling produces attenuation frequency bands, which is useful for vibration control. In this study, the coupled waves equation for a damped cable with a small curvature was proposed. Using the equation, wave frequencies and velocities were studied. Then the cable responses in the stopbands and passbands were examined. Finally, the free responses were analysed in the spatial domain. The study focused on the influence of curvature and damping on wave propagation. The results showed that the wave coupling caused by curvature was critical for producing the attenuation bands and dispersion of waves. It generated the stopbands and passbands for the wave propagation, in which the waves respectively attenuated or propagated. Furthermore, the coupling effect induced pronounced dispersion in the in-plane longitudinal waves. As for damping, it not only affected the frequencies of stopbands and passbands, but also caused wave attenuation. Damping was found to shift the cut-off frequency from the real axis to the imaginary axis and transform the stopband from a line segment into a quadrilateral area. Additionally, the relationship between frequency and wave-number evolved from a two-dimensional curve into a three-dimensional surface. What's more, damping caused wave dissipation over time. [ABSTRACT FROM AUTHOR]

Surface topographic irregularities can alter ground motion. In this study, we investigated the influence of various topographic factors such as relative elevation, slope angle, and curvature on ground-motion amplification. A finite element analysis with absorbing boundary layer was performed using actual topographic data and ground motion data from earthquakes of magnitude 3.8–9 recorded in Japan. To identify the effect of wave velocity on ground motion amplification, we considered the variability in topography and three sets of shear and longitudinal wave velocities by considering five cross-sectional profiles for the topographic models in the numerical analyses. We demonstrate that the topographic amplification factor, which is the ratio of the estimated spectral acceleration on the surface to the median spectral acceleration within the entire surface domain, is significantly influenced by curvature and relative elevation. Furthermore, we have proposed models that estimate ground-motion amplification using the two topographic factors—curvature and relative elevation—as variables. [ABSTRACT FROM AUTHOR]

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AbstractThe present paper discusses experimental results concerning the deformation-induced generation of electric potential difference in steel specimens. According to our observations, voltages in the order of 10 microVolts can be measured between points on the surfaces of steel bodies during mechanical deformation. Three different experimental set-ups were used to determine the properties of the phenomenon, carefully excluding the influence of possible external electromagnetic fields. In order to exclude thermoelectric effects, a special steel specimen was fabricated. Further experimental campaigns were conducted with long, thin metallic rods in two different set-ups: the generation of voltage was measured during the traveling of longitudinal shock waves and during bending vibrations of the specimens. The results indicate that the variation of the magnetization of the material – the magnetoelastic effect – plays an important role in the phenomenon, but thermoelectricity also contributes to the measurable voltage signals. The electromechanical effect identified in the present paper may have several applications in measurement technology. The most relevant advantage of the applied measurement methods is that these are essentially sensor-free, since the mechanical vibrations can be detected by simply soldering, welding, or pressing copper wires to the examined steel specimen. [ABSTRACT FROM AUTHOR]

In this study, the propagation of plane waves in the lanthanum gallium tantalate (langatate, LGT) single crystals is investigated. Moreover, the flight time of different waves in the LGT rectangular parallelepiped sample is measured using the ultrasonic pulse‐echo (UPE) technique, and the elastic constants of the LGT sample are determined. The experimental results clearly show echoes corresponding to the longitudinal and transverse waves along the x‐axis. The waves along the z‐axis have a similar property. However, the waves along the y‐axis are more complex than those along the x‐ and z‐axes. The echoes corresponding to the quasi‐longitudinal waves along the y‐axis are clear, but those corresponding to the transverse and quasi‐transverse waves along the y‐axis are not. The elastic constant can be accurately determined if the wave echoes corresponding to this constant propagate without distinct distortion and are clear; otherwise, it may be impossible to accurately determine the constant using UPE. All elastic constants cijE$c_{ij}^{\mathrm{E}}$ except c13E$c_{13}^{\mathrm{E}}$ of the LGT single crystals can be determined using UPE from one sample. This study uses UPE to provide a reference for the characterization of elastic constants of piezoelectric crystals with 32 symmetry from one sample. [ABSTRACT FROM AUTHOR]

Thin-walled aerospace parts have the characteristics of large size, thin wall thickness, and complex shape, etc. In the process of machining, poor rigidity and high material removal rate are easy to cause machining deformation due to uneven distribution of residual stress, and conventional detection methods and regulation means cannot meet the needs of on-site production. In order to solve these problems, an effective method of ultrasonic nondestructive in situ stress detection and ultrasonic stress regulation is proposed in this paper. Firstly, the ultrasonic residual stress detection and ultrasonic stress regulation are analyzed theoretically, and their working principles are explained, which provides a theoretical basis for the subsequent use of the equipment. Then, according to the deformable sections of large thin-walled parts in the production site, the typical characteristics are extracted to complete the design of the experimental part, and the residual stress detection and regulation of the whole machining process are studied. Finally, through two groups of comparison experiments, the changes of residual stress values in different depth ranges of parts and the changes of the flatness of the final parts are analyzed. The results show that the ultrasonic critical refraction longitudinal wave (LCR wave) method can be used to detect the residual stress of thin-walled parts in different depth ranges, and the ultrasonic stress regulation method can reduce and homogenize the stress of thin-walled parts, and the machining deformation and conformal ability of the parts are significantly improved after the stress regulation. [ABSTRACT FROM AUTHOR]

Non-suicidal self-injury (NSSI) is a major public health issue in college students. However, there is a lack of evidence on the longitudinal association between family dysfunction and NSSI as well as its underlying mediating and moderating mechanisms. Thus, we hypothesized whether depressive symptoms mediated the association between family dysfunction and NSSI, and whether this indirect effect was moderated by self-compassion. Data are from the first three waves of an ongoing longitudinal study, conducted at half-year intervals. A total of 5608 freshmen (48.2% female, Mage = 18.63, SD = 0.88) completed self-report questionnaires regarding family dysfunction, depressive symptoms, self-compassion, and NSSI. After adjusting for covariates and previous outcomes, mediation analyses revealed that depressive symptoms at T2 mediated the relationship between family dysfunction at T1 and NSSI at T3. Moderated mediation analyses revealed that self-compassion weakened the strength of the relationship between family dysfunction at T1 and depressive symptoms at T2, as well as that between depressive symptoms at T2 and NSSI at T3. This study highlights the importance of considering multiple environmental and individual factors to understand the development of NSSI. [ABSTRACT FROM AUTHOR]

Toppling deformation can be classified into deep toppling (DT) and shallow toppling (ST) based on deformation mechanisms and development depth of rock mass under different soft and hard rock conditions. Currently, the toppling zoning indicators and quantitative criteria are not uniform, and human factors have a significant influence on the toppling zoning indicators. Summerizing and analyzing the existing toppling cases and toppling zoning researches, this study selects rock layer toppled angle, maximum tension within layer, unit tension within layer, and longitudinal wave velocity as indicators for toppling zoning. Considering the differences in the characteristics of deep toppling (DT) and shallow toppling (ST), the quantitative criteria for the deep and shallow toppling zoning indicators are determined respectively. This study employs the Analytic Hierarchy Process (AHP) and fuzzy comprehensive evaluation method to establish toppling zoning evaluation models. The deep toppling dam site slope at Miaowei hydropower station and the shallow toppling bank slope of Xingguang Π formation at Xiluodu Hydropower Station were tested, respectively. These results are compared with toppling zoning of field surveys to verify the rationality and applicability of the models. This achievement holds significant reference value for the toppling zoning of rock masses in engineering slopes, especially in the construction, development, and engineering management of toppling slopes. [ABSTRACT FROM AUTHOR]

Objective To study the relationship between the education of offspring and the developmental trajectory of cognitive function in the rural elderly, and to explore the mediating effect of intergenerational support. Methods Based on seven waves of a special longitudinal survey spanning 18 years, a group-based trajectory model was used to identify the heterogeneous developmental trends of cognitive function in the rural elderly population. An unordered polytomous logistic regression was employed to study the association between offspring's education and the developmental trajectory cognitive function among the rural elderly. The KHB method was utilized to analyze the mediating effect of intergenerational support. Results A total of 1 342 elderly individuals, aged 60 to 100 years and having participated in at least two survey waves, were included. Three cognitive function trajectory groups were identified: the low decline group (19.75%), the moderate decline group (44.41%), and the high stability group (35.84%). Compared with subjects in the low decline group, those with higher levels of offspring education were more likely to belong to the moderate decline or high stability groups. Intergenerational support played a significant mediating role in this relationship, exhibiting a characteristic of need dependency. Furthermore, intergenerational economic support contributed the most to the mediating effect in each trajectory group, and robustness checks yielded similar results. Conclusion There is heterogeneity in the trajectories of cognitive function among the rural elderly. The educational achievements of offspring are an intrinsic driving force for the positive development of cognitive function in this demographic. At the same time, under the continuous impact of modern ideas and cultural waves, the traditional "filial piety culture" in rural areas of China remains deeply rooted. [ABSTRACT FROM AUTHOR]

Microwave-assisted mechanical rock breaking represents an innovative technology in the realm of mining excavation. The intricate and variable characteristics of geological formations necessitate a comprehensive understanding of the interplay between microwave-induced rock damage and the subsequent deterioration in rock strength. This study conducted microwave irradiation damage assessments on 78 distinct rock samples, encompassing granite, sandstone, and marble. A total of ten critical parameters were identified: Microwave Irradiation Time (MIT), Microwave Irradiation Power (MIP), Longitudinal Wave Velocity prior to Microwave Treatment (LWVB), Longitudinal Wave Velocity post-Microwave Treatment (LWVA), Percentage Decrease in Longitudinal Wave Velocity (LWVP), Porosity before Microwave Treatment (PB), Porosity after Microwave Treatment (PA), Percentage Increase in Porosity (PP), and Uniaxial Compressive Strength following Microwave Treatment (UCSA). Utilizing the Pied Kingfisher Optimizer (PKO) alongside Extreme Gradient Boosting (XGBoost), we developed a PKO-XGBoost machine learning model to elucidate the relationship between UCSA and the nine additional parameters. This model was benchmarked against other prevalent machine learning frameworks, with Shapley additive explanatory methods employed to assess each parameter's influence on UCSA. The findings reveal that the PKO-XGBoost model provides superior accuracy in delineating relationships among rock physical properties, microwave irradiation variables, microscopic attributes of rocks, and UCSA. Notably, PA emerged as having the most significant effect on UCSA, indicating that microwave-induced microscopic damage is a primary contributor to reductions in rock strength. Additionally, MR exhibited substantial influence; under identical microwave irradiation conditions, rocks with lower density demonstrated greater susceptibility to strength degradation. Furthermore, during microwave-assisted rock breaking operations, it is imperative to establish optimal MIT and MIP values to effectively diminish UCSA while facilitating mechanical cutting processes. The insights derived from this research offer a more rapid, cost-efficient approach for accurately assessing correlations between microwave irradiation parameters and resultant rock damage—providing essential data support for enhancing mechanical rock-breaking efficiency. [ABSTRACT FROM AUTHOR]

In the present study, we examined the prospective associations of both spousal support and spousal strain with a wide range of health and well‐being outcomes in married older adults. Applying the analytic template for outcome‐wide designs, three waves of longitudinal data from the Health and Retirement Study (n = 7788, Mage = 64.2 years) were analyzed using linear regression, logistic regression, and generalized linear models. A set of models was performed for spousal support and another set of models for spousal strain (2010/2012, t1). Outcomes included 35 different aspects of physical health, health behaviors, psychological well‐being, psychological distress, and social factors (2014/2016, t2). All models adjusted for pre‐baseline levels of sociodemographic covariates and all outcomes (2006/2008, t0). Spousal support evidenced positive associations with five psychological well‐being outcomes, as well as negative associations with five psychological distress outcomes and loneliness. Conversely, spousal strain evidenced negative associations with three psychological well‐being outcomes, in addition to positive associations with three psychological distress outcomes and loneliness. The magnitude of these associations was generally small, although some effect estimates were somewhat larger. Associations of both spousal support and strain with other social and health‐related outcomes were more negligible. Both support and strain within a marital relationship have the potential to impact various aspects of psychological well‐being, psychological distress, and loneliness in the aging population. [ABSTRACT FROM AUTHOR]

Objective: To analyze the degree, evolution and causes of socioeconomic inequality in perceived access to health services among the older adults in China. Methods: The data used in this study were drawn from the 4 waves of the Chinese Longitudinal Healthy Longevity Survey (CLHLS) in 2008, 2011, 2014, 2018. Erreygers index (EI) was used to measure socioeconomic inequality in perceived access to health services in each survey wave. A panel logit regression model was used to examine the impact of socioeconomic status on perceived access to health services. The recentered influence function (RIF) regression decomposition method was used to explore the causes of socioeconomic inequality in perceived access to health services. Inverse probability weighting (IPW) was employed to adjust estimates for missing responses and loss to follow-up. Results: "Pro-rich" socioeconomic inequality in perceived access to health services in China was found with inequality falling through time. The older adults with higher incomes, who had adequate financial support, and those who were wealthier compared with other residents reported lower socioeconomic inequality in perceived access to health services. Having basic health insurance and access to care resources when ill can help alleviate such inequalities. Conclusions: Socioeconomic inequality in perceived access to health services was shown to be responsive to policies that enhance health insurance coverage and support the provision of (paid and unpaid) caregiving for the older adults. [ABSTRACT FROM AUTHOR]

Previous studies have shown that a high prevalence of depression and anxiety is a key factor leading to a decrease in student satisfaction with university life. Therefore, this study used two waves of longitudinal data to investigate the longitudinal relationships among depression, anxiety, and student satisfaction with university life among college students. We employed correlation analysis and cross-lagged models to analyze the correlation and cross-lagged relationships among depression, anxiety, and student satisfaction with university life. The results indicate a significant negative correlation between depression and student satisfaction with university life. The cross-lagged models indicate that depression (Time 1) negatively predicts student satisfaction with university life (Time 2). Anxiety (Time 1) does not have a significant predictive effect on student satisfaction with university life (Time 2). Moreover, student satisfaction with university life negatively predicts both depression (Time 2) and anxiety (Time 2). Improving student satisfaction with university life has a significant impact on reducing levels of depression and anxiety among college students. The research results can provide valuable information for mental health professionals, school administrators, and policymakers, enabling them to take more targeted measures to reduce depression and anxiety symptoms among university students and enhance student satisfaction with university life. [ABSTRACT FROM AUTHOR]

AbstractBackgroundMethodsResultsConclusionThe elderly population of India has been growing exponentially over the past few decades, caused by a decline in fertility and an increase in life expectancy. The growth eventually has transcended the disease burden on the public healthcare system. This calls for a need to evaluate the healthcare utilization pattern of the elderly based on their socioeconomic and working condition.Study used access to public and private healthcare services to measure healthcare utilization. Descriptive analysis and multivariable logistic regression were used to understand utilization patterns by working status and some selected sociodemographic parameters. All the results were reported at a 95% confidence interval.Using the data from the first wave of Longitudinal Ageing Study in India (LASI) with a sample of 22,680 older persons 60 years and above. The study identified that 50% of the working elderly access private services; however, 26% access public healthcare services. It was found that the working status of the elderly alone did not influence access to healthcare services, but education is also an essential indicator for utilizing healthcare services. Further, factors such as gender, marital status, religion, wealth, tobacco usage, self-rated health, ADL and IADL were significant predictors of healthcare services’ utilization for the elderly.This study suggests that there are not many differences found among working and non-working status with healthcare utilization, although some sociodemographic indicators are associated with the utilization of healthcare services, highlighting that increasing health needs among the elderly requires strengthening the quality and appropriate public investment in health. [ABSTRACT FROM AUTHOR]

Objective Background Method Results Conclusion This study identifies subtypes of families with varying levels of economic and relational resilience during the pandemic and evaluates the factors associated with these subtypes in Singapore.Despite mounting evidence on the detrimental impact of the pandemic on family well‐being, we examine how resources at different levels may enhance family resilience.A sample of 2818 households was extracted from two waves of the Singapore Longitudinal Early Development Study (SG‐LEADS). Latent class analysis was conducted to classify subgroups of families. Multinomial logistic regression was applied to examine the association between the subgroup membership and multilevel factors including mother's self‐efficacy, family socioeconomic status, quality of family time, mother's work‐life conflict, partner cooperation, neighborhood environment, and government and community support.We identified six distinct groups of families: “economically and relationally fragile” (4%), “economically struggling but relationally improved” (11%), “economically struggling but relationally stable” (14%), “economically secure and relationally stable” (28%), “economically secure but relationally deteriorating” (11%) and “economically secure and relationally strengthened” (31%). Families with higher socioeconomic status tend to show economic resilience. Families with mothers exhibiting higher self‐efficacy and lower work‐life conflict, coupled with quality family time, better neighborhood, greater government and community support, are more relationally resilient.The study provides a nuanced picture of family dynamics under a global crisis, highlighting the multilevel resources that are correlated with family resilience. [ABSTRACT FROM AUTHOR]

In order to obtain the failure mechanism of the rock stability under the influence of carbonaceous phyllite band in tailrace surge chamber of Jinchuan Hydropower Station, an insitu microseismic(MS)monitoring system was established. In the construction period, the temporal and spatial distribution of MS events and source parameters were acquired during the excavation in underground caverns. A 3D discrete element numerical model was built. Discrete fracture network(DFN)was added for the weak fault of the underground caverns to build joint fissure, and the displacement and plastic zone distribution were obtained. The synthetic MS events induced by the excavation validated the failure mode and damage of the weak fault. The results suggested that there was a strong correlation between the spatial distribution of insitu MS events and the failure region of rock. The source parameter energy ratio of transverse and longitudinal waves of MS events revealed that the main failure mode of tailrace surge chamber was tension failure. The maximum deformation and plastic zone were obtained by discrete element numerical simulation, and the result was mutually verified with the MS monitoring results. The synthetic MS events generated by DFN-discrete element coupling method revealed the potential failure area of rock, and the result was in good agreement with the actual spatial distribution of MS events. [ABSTRACT FROM AUTHOR]

Purpose: Political participation has been identified as a predictor of mental health. Previous research studies have reported mixed results concerning the relationship between political participation and mental health. Moreover, findings have generally been confined to the between‐individual level. The few studies that investigated within‐person associations have not examined bidirectionality. In the current study, the bidirectional relationship between political participation and mental health was investigated. Methods: Data from the GESIS Panel study were used to assess the bidirectional association between political participation and mental health. The GESIS Panel study is a probability‐based panel representative of the German‐speaking population residing in Germany and aged between 18 and 70 years (M = 44.52; SD = 14.67; 52 percent female participants). Mental health was assessed using measures of depression symptoms and subjective well‐being. Results: Using up to nine waves of longitudinal survey data, a random‐intercept cross‐lagged panel model indicated little evidence for cross‐lagged effects from political participation to mental health or vice versa. Notwithstanding, few significant cross‐lagged paths were observed. Conclusions: Overall, the findings were not consistent with the theorized effect of political participation on mental health. Moreover, there is little evidence that mental health affects political participation. [ABSTRACT FROM AUTHOR]

Fully enclosed noise barriers (FENBs) are increasingly being installed on high-speed railway bridges for noise pollution control. However, the aerodynamic effects of high-speed trains passing FENBs have an adverse impact on barrier durability and generate micro-pressure waves. In this paper, a numerical model of a train passing an FENB on a bridge is established. The aerodynamic pressure distribution along the FENB is analyzed for both a single train and two trains passing one another. The propagation characteristics and evolution mechanisms of pressure waves are then investigated. The results show that the pressure is lower at the ends of the FENB and higher in the middle along the direction of train travel. The peak positive and negative pressures at the mid-span are 1.95 and 4.47 times higher than those at the ends, respectively. This distribution is caused by the propagation, superposition, reflection, and attenuation of pressure waves. Compression waves account for 78.9% of the peak positive pressure. An amplification factor must be considered when estimating the impact of two trains passing one another. Analysis of five pressure-relief schemes shows that arranging a single pressure-relief hole at a high-pressure location effectively alleviates the over-pressure in the FENB. The overall pressure-relief effect is an exponential function of the single opening area. Considering a constant opening area, arranging several relief holes at equal spacing optimizes the adverse pressure distribution compared with the single-hole relief scheme. The equivalent forces of the multi-hole scheme are 3.35% and 7.58% lower than in the single-hole scheme. [ABSTRACT FROM AUTHOR]

The considerable increase in train velocity has intensified mutual aerodynamic effects between a train and a tunnel. How to effectively reduce the micro-pressure wave (MPW) amplitude at the high-speed railway tunnel exit is significantly important and has been recognized as an extremely challenging study, especially for the high-speed maglev tunnel when the train travels through it at 400 km/h or even more. To effectively mitigate the phenomenon of "sound explosion" caused by micro-pressure waves, this study provided a newly novel solution to mitigate the micro-pressure wave amplitude, which breaks up the traditional design idea and introduces a completely new arch lattice-shell structure inside the tunnel hood. In addition, the effect of the arch lattice-shell length on initial compression waves at high-speed maglev tunnel entrance and MPWs at exit were analyzed. The findings indicate that compared to the typical section-expanded tunnel hood, the new section-expanded lattice-shell hoods have a positive effect on the mitigation of micro-pressure waves emitted at the high-speed maglev tunnel exit. As the hood length increases, the alleviating effect is strengthened, resulting in a substantial decrease in the peak of the pressure gradient (Pg) and amplitudes of MPWs. When the section-expanded lattice-shell hoods are 50, 80, and 100 m in length, the pressure gradient peaks (Pg) are decreased by 6.2%, 34.9%, and 41.8%, respectively, while the corresponding amplitudes of MPWs are reduced by 9.4%, 46.8%, and 51.9%, respectively. Therefore, the new arch lattice-shell structure added inside the section-expanded tunnel hood can significantly mitigate the amplitudes of MPWs, which provides a newly novel solution for the tunnel hood design during the high-speed train passing through the tunnel at a higher speed. [ABSTRACT FROM AUTHOR]

Qingshankou shale (Gulong area, China) exhibits strong acoustic anisotropy characteristics, posing significant challenges to its exploration and development. In this study, the five full elastic constants and multipole response law of the Qingshankou shale were studied using experimental measurements. Analyses show that the anisotropy parameters ϵ and γ in the study region are greater than 0.4, whereas the anisotropy parameter δ is smaller, generally 0.1. Numerical simulations show that the longitudinal and transverse wave velocities of these strong anisotropic rocks vary significantly with inclination angle, and significant differences in group velocity and phase velocity are also present. Acoustic logging measures the group velocity in dipped boreholes; this differs from the phase velocity to some extent. As the dip angle increases, the longitudinal and SH wave velocities increase accordingly, while the qSV-wave velocity initially increases and then decreases, reaching its maximum value at a dip of approximately 40°. These results provide an effective guide for the correction and modeling of acoustic logging time differences in the region. [ABSTRACT FROM AUTHOR]

Ethnic identity is a major area of study across many disciplines including psychology, sociology, anthropology, and political science. Yet, little is known about changes in ethnic identity across the adult lifespan, and whether such changes are driven by normal aging processes (aging effects), unique societal influences linked with one's formative years (cohort effects), or social changes during a specific time frame (period effects). We address these key oversights by utilizing 13 annual waves of longitudinal panel data from a nationwide random sample of both ethnic majority (N = 49,660) and Indigenous ethnic minority (N = 8,325) group members in New Zealand to examine changes in ethnic identity centrality using cohort-sequential latent growth modeling. This approach helps to identify changes in mean levels of ethnic identity centrality over time and whether such changes are driven by aging, cohort, and/or period effects. Our data reveal that, among both ethnic majority and ethnic minority individuals, changes in ethnic identity centrality were informed by a combination of normative aging processes, societal circumstances that reflected the unique historical context in which people grew to maturity, and societal changes during the 13 annual assessments of our study. Collectively, these results demonstrate for the first time that ethnic identity centrality in adulthood is subject to lifelong changes. [ABSTRACT FROM AUTHOR]

Does position in the friendship network affect social status in early adolescence? Previous research shows that friendship relations are not equivalent to popularity hierarchies, but favorable positions in the friendship network should allow students to gain status. We use four waves of longitudinal network data and dynamic panel models with fixed effects to estimate the impact of network position on social status. Degree centrality and brokerage opportunity both exert large impacts on status, even compared against the effect of prior status. The results suggest future research on friendship across social identities, as well as network structure and hierarchy in adolescent social systems. [ABSTRACT FROM AUTHOR]

High-voltage cables are the main arteries of urban power supply. Cable accessories are connecting components between different sections of cables or between cables and other electrical equipment. The stress in the cold shrink tube of cable accessories is a key parameter to ensure the stable operation of the power system. This paper attempts to explore a method for measuring the stress in the cold shrink tube of high-voltage cable accessories based on ultrasonic longitudinal wave attenuation. Firstly, a pulse ultrasonic longitudinal wave testing system based on FPGA is designed, where the ultrasonic sensor operates in a single-transmit, single-receive mode with a frequency of 3 MHz, a repetition frequency of 50 Hz, and a data acquisition and transmission frequency of 40 MHz. Then, through experiments and theoretical calculations, the transmission and attenuation characteristics of ultrasonic longitudinal waves in multi-layer elastic media are studied, revealing an exponential relationship between ultrasonic wave attenuation and the thickness of the cold shrink tube. Finally, by establishing a theoretical model of the radial stress of the cold shrink tube, using the thickness of the cold shrink tube as an intermediate variable, an effective measurement of the stress of the cold shrink tube was achieved. [ABSTRACT FROM AUTHOR]

ZnO film ultrasonic transducers for temperature and stress measurements with dual-mode wave excitation (longitudinal and shear) were deposited using the reactive RF magnetron sputtering technique on Si and stainless steel substrates and construction steel bolts. It was found that the position in the substrate plane had a significant effect on the structure and ultrasonic performance of the transducers. The transducers deposited at the center of the deposition zone demonstrated a straight columnar structure with a c-axis parallel to the substrate normal and the generation of longitudinal waves. The transducers deposited at the edge of the deposition zone demonstrated inclined columnar structures and the generation of dominant shear or longitudinal shear waves. Transducers deposited on the bolts with dual-wave excitation were used to study the effects of high temperatures in the range from 25 to 525 °C and tensile stress in the range from 0 to 268 MPa on ultrasonic response. Dependencies between changes in the relative time of flight and temperature or axial stress were obtained. The dependencies can be described by second-order functions of temperature and stress. An analysis of the contributions of thermal expansion, strain, and the speed of sound to changes in the time of flight was performed. At high temperatures, a decrease in the signal amplitude was observed due to the decreasing resistivity of the transducer. The ZnO ultrasonic transducers can be used up to temperatures of ~500 °C. [ABSTRACT FROM AUTHOR]

The article is about the study of reflected waves through the surface of an elastic solid. The medium considered for the propagation of waves is homogeneous isotropic with semiconductor properties. The thermoelastic properties of the medium are a function of temperature. The governing equations are formulated by using non-local elastic theory. The conduction process of heat is studied by using the concept of three-phase lag along with fractional order time derivative. After reflecting through the surface one transverse and three longitudinal waves travel back into the media. The reflection coefficients and their energy ratios are computed analytically. Numerically simulated results are obtained for the intrinsic semiconductor material Silicon to depict the effect of temperature dependency parameters, nonlocal parameters, and time derivative fractional order on the different reflection coefficients. Some published results are also discussed as special cases. [ABSTRACT FROM AUTHOR]

Peridynamics describes the material in a non-local form and is very suited for the simulation of dynamic fracture. However, one significant effect regarding dynamic fracture is the correct handling of elastic deformation, like the pressure and tension waves inside a body, due to dynamic boundary conditions like an impact or impulse. Many peridynamic material formulations have been developed with differences in this regard. This study investigates the elastic wave propagation characteristics of bond-based, ordinary state-based, continuum kinematics-inspired peridynamics and a local continuum consistent correspondence formulation. Multiple parameters of a longitudinal pressure wave inside an elastic bar are studied. While all formulations demonstrate adequate wave propagation handling, all except the correspondence formulation are sensitive to incomplete horizons. The local continuum consistent formulation does not suffer from the surface effect and models the wave propagation with perfect accuracy. [ABSTRACT FROM AUTHOR]

Although overparenting is a growing phenomenon across the globe, there is a severe lack of longitudinal studies examining the trajectory of overparenting and its effects on early adolescent development, particularly in non‐Western contexts. The study collected three waves of longitudinal data from 1328 early Chinese adolescents in Hong Kong with an interval of 1 year to examine the stability and change of perceived paternal and maternal overparenting and their effects on adolescent psychological wellbeing. The results indicated that perceived paternal and maternal overparenting declined over time. Besides, adolescents reported lower anxiety and depressive symptoms when they perceived a steep decline in maternal overparenting. Adolescent anxiety at earlier time points also predicted a steeper decline in paternal and maternal overparenting trajectories respectively. Furthermore, we identified gender differences in the initial level of paternal overparenting and the trajectory of maternal overparenting, as well as the effects of rates of change of maternal overparenting on adolescent anxiety and depressive symptoms. The findings give support for self‐determination theory and the separation‐individuation model, suggesting that changes of overparenting may hinder adolescents' desires for autonomy and self‐direction, which may increase their psychological morbidity. The study contributes to theoretical development of contemporary Chinese socialization models and provides useful pointers for future studies of overparenting. [ABSTRACT FROM AUTHOR]

In this research, rock mass deformation modulus (Emass), classification of rock mass, cohesion (c) and internal friction angle (Φ), and intact rock properties of the Khersan 2 dam site were investigated. Factors affecting mechanical properties were investigated and compared with the results of previous studies. To assess the shear strength and the Hoek and Brown failure criteria parameters, the triaxial test was performed on samples under saturated conditions. The Q-system and rock mass rating (RMR) were calculated for five-metre sections of boreholes. Results of the Mohr–Coulomb failure criterion showed that the limestones have a mean Φ of 40 degrees and a mean cohesion of 1 MPa, marl limestones have an average of 30 degrees and cohesion of 0.50 MPa, and anhydrite and gypsum showed an average of 26 degrees and 0.10 MPa. The results showed that c and Φ increase with the increase in the shear box size. Based on the RMR and Q-system the site was classified in good class. The mean of Emass showed that the dilatometry test gives the lowest value. Linear and logarithmic relationships were established between RMR89 with compressional wave velocity (Vp) (R2 = 0.95 and RMSE = 1.63) and Q-system (R2 = 0.95 and RMSE = 2.05), respectively. [ABSTRACT FROM AUTHOR]

Background and Objectives: Limited longitudinal research has examined differential interpersonal and intrapersonal correlates of young adult use and use frequency of cigarettes, e‐cigarettes, and cannabis. This study aimed to address these limitations. Methods: We analyzed five waves of longitudinal data (2018–2020) among 3006 US young adults (Mage = 24.55, 44% male, 32% sexual minority, ~30% racial/ethnic minority). Two‐part latent growth models examined likelihood of past‐month cigarette, e‐cigarette, and cannabis use (binary part) and days used (continuous part) and identified predictors (depressive symptoms, personality traits, adverse childhood experiences [ACEs], parental use) of baseline use and changes over time. Results: Regarding baseline past‐month use (27% cigarettes, 38% e‐cigarettes, 39% cannabis), depressive symptoms, ACEs, and parental substance use predicted use outcomes (i.e., likelihood, frequency) for each product; extraversion predicted cigarette and e‐cigarette use outcomes; openness predicted e‐cigarette and cannabis use outcomes; conscientiousness negatively predicted cigarette and cannabis use outcomes; and agreeableness negatively predicted cannabis use frequency. Regarding longitudinal changes, conscientiousness predicted accelerated increase of cigarette use frequency at later timepoints; depressive symptoms predicted increases in likelihood of e‐cigarette use but the association weakened over time; and parental cannabis use predicted decreased cannabis use frequency but the association weakened over time. Discussion and Conclusions: Young adult substance use interventions should target high‐risk subgroups and focus on distinct factors impacting use, including chronic, escalating, and decreasing use. Scientific Significance: This study advances the literature regarding distinct predictors of different substance use outcomes and provides unique data to inform interventions targeting young adult cigarette, e‐cigarette, and cannabis use. [ABSTRACT FROM AUTHOR]

Acoustic logging is an important method used to determine formation velocities near boreholes. However, in practice, determining accurate formation velocities from acoustic logging data is challenging because of the presence of various noise interferences. Accordingly, a method to increase the amplitudes of refracted waves in open boreholes is proposed herein on the basis of the directional radiation technology of pulse compression signal–driven linear phased array acoustic transmitters. The waveforms generated by a Ricker monopole acoustic transmitter, linear frequency modulation monopole acoustic transmitter and pulse compression signal–driven linear phased array acoustic transmitter in a fluid‐filled open borehole are numerically simulated by employing the finite‐difference method. The effects of the pulse compression signal–driven linear phased array parameters on the amplitudes of the refracted compressional and shear waves are studied. Results show that borehole mode waves with the same velocities and dispersion characteristics can be determined using the pulse compression signal–driven linear phased array acoustic and Ricker monopole acoustic transmitters in fluid‐filled open boreholes. Pulse compression signal–driven linear phased array acoustic transmitters leverage the advantages of pulse compression and phased array technologies, ensuring that a single element can radiate more acoustic energy, whereas pulse compression signal–driven linear phased array parameters can be modulated to further increase the amplitudes of the refracted compressional and shear waves. Compared with Ricker and linear frequency modulation monopole acoustic transmitters, pulse compression signal–driven linear phased array acoustic transmitters can provide downhole received waveforms of better quality and improved a signal‐to‐noise ratio of the mode wave dispersion curves obtained using the downhole received waveforms. Because pulse compression signal–driven linear phased array acoustic transmitters use linear frequency modulation drive signals of longer duration, the recording time required for the received waveforms is also longer and the amount of data generated is larger, presenting new challenges for downhole data processing and high‐speed data transmission. [ABSTRACT FROM AUTHOR]

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For laser ultrasound in the thermoelastic mechanism, excitation of ultrasonic body wave signal is weak, it is not easy to realize the detection of deep defects inside the workpiece. While the ablation mechanism produces a high and practical ultrasonic signal-to-noise ratio, this paper is based on the generation mechanism of laser ablation excitation of ultrasonic waves, the establishment of laser ultrasound in the ablation mechanism in the aluminum plate excitation and propagation of ultrasonic numerical model, through the solution, obtained the ultrasonic acoustic field map, discussed the ablation mechanism of the laser ultrasonic body wave acoustic field directionality. Additionally, the preliminary verification of the validity of the model is presented. Then, in order to explore the application potential of high signal-to-noise ratio longitudinal waves in defect detection, defects of different depths are preset in the model for simulation calculations, and waveform and acoustic field analyses are performed on the simulation results to study the ultrasonic propagation paths inside the member and the interaction with the defects, and the transverse position and depth of the internal defects are judged by using B-scan imaging. Finally, experimental validation is carried out. The experimental results are highly consistent with the simulation model, and the defect experiments can qualitatively determine the location of internal defects and verify the practicality and accuracy of the model. [ABSTRACT FROM AUTHOR]

Psychosocial properties of oral health have been reported. The present study aimed to investigate the causal effect of complete loss of natural teeth on loneliness by using fixed-effects analysis to control for confounding factors, including unmeasured time-invariant factors. Data from older adults participating in at least 2 consecutive waves of the English Longitudinal Study of Ageing in waves 3 (2006/2007), 5 (2010/2011), and 7 (2014/2015) were analyzed (N = 18,682 observations from 7,298 individuals). The association between complete loss of natural teeth and loneliness score (ranging from 3 to 9) was examined using fixed-effect linear regression analysis adjusting for time-varying confounders, including sociodemographic and health characteristics. The prevalence of complete tooth loss was 12.7%, 12.8%, and 10.6% in waves 3, 5, and 7, respectively. Individuals who transitioned to complete tooth loss during any 2 consecutive waves had an increase in loneliness score by 0.27 (95% confidence interval [CI] 0.03, 0.52), which was greater than those who maintained natural teeth (−0.03; 95% CI −0.05, −0.01). Fixed-effects analysis adjusting for time-varying confounders revealed a significant association between complete loss of natural teeth and an increase in loneliness score by 0.31 (95% CI 0.17, 0.46). Complete loss of natural teeth among older adults in England was associated with loneliness, even after accounting for measured time-varying and (un)measured time-invariant confounders. Retaining natural teeth may reduce the risk of loneliness. [ABSTRACT FROM AUTHOR]