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Search Results (362)

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Keywords = attenuation equation

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19 pages, 4432 KiB  
Article
Radial Temperature Distribution Characteristics of Long-Span Transmission Lines Under Forced Convection Conditions
by Feng Wang, Chuanxing Song, Xinghua Chen and Zhangjun Liu
Processes 2025, 13(7), 2273; https://doi.org/10.3390/pr13072273 - 16 Jul 2025
Viewed by 290
Abstract
This study proposes an iterative method based on thermal equilibrium equations to calculate the radial temperature distribution of long-span overhead transmission lines under forced convection. This paper takes the ACSR 500/280 conductor as the research object, establishes the three-dimensional finite element model considering [...] Read more.
This study proposes an iterative method based on thermal equilibrium equations to calculate the radial temperature distribution of long-span overhead transmission lines under forced convection. This paper takes the ACSR 500/280 conductor as the research object, establishes the three-dimensional finite element model considering the helix angle of the conductor, and carries out the experimental validation for the LGJ 300/40 conductor under the same conditions. The model captures internal temperature distribution through contour analysis and examines the effects of current, wind speed, and ambient temperature. Unlike traditional models assuming uniform conductor temperature, this method reveals internal thermal gradients and introduces a novel three-stage radial attenuation characterization. The iterative method converges and accurately reflects temperature variations. The results show a non-uniform radial distribution, with a maximum temperature difference of 8 °C and steeper gradients in aluminum than in steel. Increasing current raises temperature nonlinearly, enlarging the radial difference. Higher wind speeds reduce both temperature and radial difference, while rising ambient temperatures increase conductor temperature with a stable radial profile. This work provides valuable insights for the safe operation and optimal design of long-span transmission lines and supports future research on dynamic and environmental coupling effects. Full article
(This article belongs to the Section Energy Systems)
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21 pages, 918 KiB  
Article
Analysis of Ultrasonic Wave Dispersion in Presence of Attenuation and Second-Gradient Contributions
by Nicola De Fazio, Luca Placidi, Francesco Fabbrocino and Raimondo Luciano
CivilEng 2025, 6(3), 37; https://doi.org/10.3390/civileng6030037 - 14 Jul 2025
Viewed by 156
Abstract
In this study, we aim to analyze the dispersion of ultrasonic waves due to second-gradient contributions and attenuation within the framework of continuum mechanics. To investigate dispersive behavior and attenuation effects, we consider the influence of both higher-order gradient terms (second gradients) and [...] Read more.
In this study, we aim to analyze the dispersion of ultrasonic waves due to second-gradient contributions and attenuation within the framework of continuum mechanics. To investigate dispersive behavior and attenuation effects, we consider the influence of both higher-order gradient terms (second gradients) and Rayleigh-type viscoelastic contributions. To this end, we employ the extended Rayleigh–Hamilton principle to derive the governing equations of the problem. Using a wave-form solution, we establish the relationship between the phase velocity and the material’s constitutive parameters, including those related to the stiffness of both standard (first-gradient) and second-gradient types, as well as viscosity. To validate the model, we use data available in the literature to identify all the material parameters. Based on this identification, we observe that our model provides a good approximation of the experimentally measured trends of both phase velocity and attenuation versus frequency. In conclusion, this result not only confirms that our model can accurately describe both wave dispersion and attenuation in a material, as observed experimentally, but also highlights the necessity of simultaneously considering both second-gradient and viscosity parameters for a proper mechanical characterization of materials. Full article
(This article belongs to the Section Mathematical Models for Civil Engineering)
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17 pages, 3679 KiB  
Article
Binary-Classification Physical Fractal Models in Different Coal Structures
by Guangui Zou, Yuyan Che, Tailang Zhao, Yajun Yin, Suping Peng and Jiasheng She
Fractal Fract. 2025, 9(7), 450; https://doi.org/10.3390/fractalfract9070450 - 8 Jul 2025
Viewed by 250
Abstract
Existing theoretical models of wave-induced flow face challenges in coal applications due to the scarcity of experimental data in the seismic-frequency band. Additionally, traditional viscoelastic combination models exhibit inherent limitations in accurately capturing the attenuation characteristics of rocks. To overcome these constraints, we [...] Read more.
Existing theoretical models of wave-induced flow face challenges in coal applications due to the scarcity of experimental data in the seismic-frequency band. Additionally, traditional viscoelastic combination models exhibit inherent limitations in accurately capturing the attenuation characteristics of rocks. To overcome these constraints, we propose a novel binary classification physical fractal model, which provides a more robust framework for analyzing wave dispersion and attenuation in complex coal. The fractal cell was regarded as an element to re-establish the viscoelastic constitutive equation. In the new constitutive equation, three key fractional orders, α, β, and γ, emerged. Among them, α mainly affects the attenuation at low frequencies; β controls the attenuation in the middle-frequency band; and γ dominates the attenuation in the tail-frequency band. After fitting with the measured attenuation data of partially saturated coal samples under variable confining pressures and variable temperature conditions, the results show that this model can effectively represent the attenuation characteristics of elastic wave propagation in coals with different coal structures. It provides a new theoretical model and analysis ideas for the study of elastic wave attenuation in tectonic coals and is of great significance for an in-depth understanding of the physical properties of coals and related geophysical prospecting. Full article
(This article belongs to the Special Issue Fractal Dimensions with Applications in the Real World)
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29 pages, 5719 KiB  
Article
Cross-Floor Vibration Wave Propagation in High-Rise Industrial Buildings Under TMD Control
by Ruoyang Zhou and Xiaoxiong Zha
Infrastructures 2025, 10(7), 169; https://doi.org/10.3390/infrastructures10070169 - 3 Jul 2025
Viewed by 282
Abstract
High-rise industrial buildings are particularly susceptible to vibration-induced comfort issues, which can negatively impact both the health and productivity of workers and office staff. Unlike most existing studies that focus on local structural components, this study proposes and validates a wave propagation analysis [...] Read more.
High-rise industrial buildings are particularly susceptible to vibration-induced comfort issues, which can negatively impact both the health and productivity of workers and office staff. Unlike most existing studies that focus on local structural components, this study proposes and validates a wave propagation analysis (WPA) method to predict peak accelerations of the floor caused by excitations located on different floors. The method is validated through on-site vibration tests conducted on a high-rise industrial building with shared factory and office space. A simplified regression-based propagation equation is further developed to facilitate practical design applications. The regression parameters are fitted using theoretical calculation results, enabling rapid prediction of peak acceleration responses on the same or different floors. To enhance vibration control, tuned mass dampers (TMDs) are installed on selected floors, and additional tests are conducted with the TMDs activated. An insertion loss-based correction is introduced into the WPA framework to account for the TMD’s frequency-dependent attenuation effects. The extended method supports both accurate prediction of vibration reduction and optimisation of TMD placement across multiple floors in high-rise industrial buildings. Full article
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20 pages, 5908 KiB  
Article
Horizontal UHS Predictions for Varying Deep Geology Conditions—A Case Study of the City of Banja Luka
by Borko Bulajić, Silva Lozančić, Senka Bajić, Dorin Radu, Ercan Işık, Milanka Negovanović and Marijana Hadzima-Nyarko
Sustainability 2025, 17(13), 6012; https://doi.org/10.3390/su17136012 - 30 Jun 2025
Cited by 2 | Viewed by 338
Abstract
In this study, we show how uniform hazard spectra (UHS) can contribute to sustainable development in regions with frequent moderate to strong seismic events and a variety of deeper geological conditions, by reducing seismic risks and enhancing resilience. The case study region surrounds [...] Read more.
In this study, we show how uniform hazard spectra (UHS) can contribute to sustainable development in regions with frequent moderate to strong seismic events and a variety of deeper geological conditions, by reducing seismic risks and enhancing resilience. The case study region surrounds a site at Banja Luka, Bosnia and Herzegovina. Frequency-dependent scaling equations are presented. UHS spectra for Banja Luka are calculated utilizing regional seismicity estimations, deep geology data, and the regional empirical formulae for scaling different PSA amplitudes. The UHS amplitudes are compared with Eurocode 8 spectra. The results demonstrate that the ratios of the highest UHS amplitudes to the corresponding PGA values differ significantly from 2.5, which is the factor specified by Eurocode 8 for the horizontal ground motion. The results also suggest that the influence of deep geology on UHS amplitudes can outweigh local soil effects. For example, at the vibration period of 0.1 s, the largest site effects are obtained for deep geology when comparing the UHS amplitude at geological rock to that at intermediate sites. In this case, the deep geology amplification of 1.47 is 19% higher than the local soil amplification of 1.24 for the same vibration period at the stiff soil sites compared to the rock soil sites. The UHS obtained may be interpreted as preliminary for Banja Luka and other places with similar deep geology, local soil conditions, and seismicity. When the quantity of strong-motion data in the region increases significantly beyond what it is now, it will be possible to correctly calibrate the existing attenuation equations and obtain more reliable UHS estimates. Full article
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20 pages, 3057 KiB  
Article
An Interval Prediction Method Based on TSKANMixer Architecture for Predicting the State of Health of Lithium-Ion Batteries
by Fang Guo, Haolin Huang, Guangshan Huang and Zitao Chen
Electronics 2025, 14(13), 2608; https://doi.org/10.3390/electronics14132608 - 27 Jun 2025
Viewed by 225
Abstract
Current state-of-health (SOH) point prediction methods are highly accurate during early cycles. However, the prediction error increases significantly with increasing numbers of battery charging and discharging cycles, especially in the later stages of degradation. This leads to the intensification of uncertainty regarding SOH, [...] Read more.
Current state-of-health (SOH) point prediction methods are highly accurate during early cycles. However, the prediction error increases significantly with increasing numbers of battery charging and discharging cycles, especially in the later stages of degradation. This leads to the intensification of uncertainty regarding SOH, which seriously affects the accuracy and safety of judgments about battery failure. To solve this problem and overcome the limitation of human parameter tuning, this study proposes a method for predicting the SOH interval of lithium batteries based on a stochastic differential equation (SDE) and the chaotic evolutionary optimization (CEO) algorithm to optimize the TSKANMixer network. First, battery charge/discharge curves are analyzed, and health features were extracted to establish a SOH estimation model based on TSKANMixer. Then, the hyperparameters of the TSKANMixer model were optimized using the CEO algorithm to further improve the prediction performance. Finally, the prediction of SOH intervals was implemented using SDE based on the CEO-TSKANMixer model. The results show that the CEO optimization brought the RMSE of SOH prediction for the three cells down to no more than 1%, which was 72.70% lower than that of the baseline model. The PICP of the SDE-based interval prediction model exceeded 90% for all of them, and the NMPIW was no more than 6.47%. This indicates that the model can accurately quantify the SOH uncertainty and effectively support the early warning of the risk of battery failure in the late stages of attenuation. The method can also be used for SOH interval prediction for subsequent battery clusters, reducing the computational complexity of cell-by-cell analysis and improving the overall efficiency of battery management systems. Full article
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27 pages, 1098 KiB  
Article
Complex-Valued Electromagnetic Fields in Matter: Their Relevance to Electromagnetic Field Theories of Conscious Experience
by James A. Reggia
Symmetry 2025, 17(7), 992; https://doi.org/10.3390/sym17070992 - 24 Jun 2025
Viewed by 309
Abstract
It has previously been shown that complex-valued electromagnetic fields can substantially increase the symmetry of Maxwell’s Equations (MEs). They are consistent with known experimental findings in classical electrodynamics and result in some interesting predictions. For example, complex MEs predict the existence of magnetic [...] Read more.
It has previously been shown that complex-valued electromagnetic fields can substantially increase the symmetry of Maxwell’s Equations (MEs). They are consistent with known experimental findings in classical electrodynamics and result in some interesting predictions. For example, complex MEs predict the existence of magnetic monopoles that would have escaped detection in past experimental searches for them. This paper extends the basic complex-valued MEs for use inside matter. The increased symmetry of the extended MEs is demonstrated by an electromagnetic duality transformation analogous to that of the standard MEs and a fundamentally new type of duality transform. A derived wave equation unexpectedly shows that the imaginary-valued portion of waves inside of matter propagates without attenuation or reduced speed. Demonstrating the existence of the imaginary-valued field components predicted by this theory could have substantial implications for understanding physical and biological phenomena. To illustrate this, ways in which imaginary-valued field components would contribute to existing electromagnetic field theories of consciousness are described. The ability of complex-valued fields to account for disparate phenomena (failure of past experimental searches to find magnetic monopoles; several poorly understood features of subjective time and memory) increases the probability of their existence. Full article
(This article belongs to the Section Physics)
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18 pages, 1108 KiB  
Article
Three-Phase-Lag Effect on Rayleigh Waves in a Generalized Thermoelastic Diffusion Medium with Modified Couple Stress
by Emad K. Jaradat, Sayed M. Abo-Dahab, Rajneesh Kumar and Eslam S. Elidy
Crystals 2025, 15(7), 588; https://doi.org/10.3390/cryst15070588 - 22 Jun 2025
Viewed by 327
Abstract
This study examines the behavior of Rayleigh waves propagating through a homogeneous, isotropic material, analyzed using a three-phase-lag thermoelastic diffusion framework enhanced by modified couple stress theory. The mathematical model integrates coupled thermoelastic and diffusive effects, incorporating phase-lags associated with (1) temperature gradients, [...] Read more.
This study examines the behavior of Rayleigh waves propagating through a homogeneous, isotropic material, analyzed using a three-phase-lag thermoelastic diffusion framework enhanced by modified couple stress theory. The mathematical model integrates coupled thermoelastic and diffusive effects, incorporating phase-lags associated with (1) temperature gradients, (2) heat flux, and (3) thermal displacement gradients. By solving the derived governing equations analytically subject to stress-free, thermally insulated, and impermeable boundary conditions, we obtain the characteristic secular equation for Rayleigh wave propagation. Numerical simulations conducted on a copper medium evaluate how the secular equation’s determinant, wave velocity, and attenuation coefficient vary with angular frequency. The analysis focuses particularly on the influence of phase-lag parameters, including thermal and diffusion gradients and relaxation times. Results demonstrated that increasing the displacement gradient phase-lag elevated the secular determinant but reduced wave velocity and attenuation, while temperature gradient phase-lags exhibited the opposite trend. The study highlights the sensitivity of Rayleigh wave propagation to thermo-diffusive coupling and microstructural effects, offering insights applicable to seismic wave analysis, geophysical exploration, and material processing. Comparisons with prior theories underscore the model’s advancement in capturing size-dependent and memory-dependent phenomena. Full article
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27 pages, 4277 KiB  
Article
Probability Density Evolution and Reliability Analysis of Gear Transmission Systems Based on the Path Integration Method
by Hongchuan Cheng, Zhaoyang Shi, Guilong Fu, Yu Cui, Zhiwu Shang and Xingbao Huang
Lubricants 2025, 13(6), 275; https://doi.org/10.3390/lubricants13060275 - 19 Jun 2025
Viewed by 461
Abstract
Aimed at dealing with the problems of high reliability solution cost and low solution accuracy under random excitation, especially Gaussian white noise excitation, this paper proposes a probability density evolution and reliability analysis method for nonlinear gear transmission systems under Gaussian white noise [...] Read more.
Aimed at dealing with the problems of high reliability solution cost and low solution accuracy under random excitation, especially Gaussian white noise excitation, this paper proposes a probability density evolution and reliability analysis method for nonlinear gear transmission systems under Gaussian white noise excitation based on the path integration method. This method constructs an efficient probability density evolution framework by combining the path integration method, the Chapman–Kolmogorov equation, and the Laplace asymptotic expansion method. Based on Rice’s theory and combined with the adaptive Gauss–Legendre integration method, the transient and cumulative reliability of the system are path integration method calculated. The research results show that in the periodic response state, Gaussian white noise leads to the diffusion of probability density and peak attenuation, and the system reliability presents a two-stage attenuation characteristic. In the chaotic response state, the intrinsic dynamic instability of the system dominates the evolution of the probability density, and the reliability decreases more sharply. Verified by Monte Carlo simulation, the method proposed in this paper significantly outperforms the traditional methods in both computational efficiency and accuracy. The research reveals the coupling effect of Gaussian white noise random excitation and nonlinear dynamics, clarifies the differences in failure mechanisms of gear systems in periodic and chaotic states, and provides a theoretical basis for the dynamic reliability design and life prediction of nonlinear gear transmission systems. Full article
(This article belongs to the Special Issue Nonlinear Dynamics of Frictional Systems)
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13 pages, 1018 KiB  
Article
Nonlinear Shear Waves in Compressible Media: Occurrence of Strong Shocks
by Vladimir Bratov and Sergey V. Kuznetsov
Mathematics 2025, 13(12), 1991; https://doi.org/10.3390/math13121991 - 17 Jun 2025
Viewed by 300
Abstract
Apparently for the first time, shear shock wave fronts (shear shocks) are observed in a hyperfoam at the propagation of shear waves. The hyperfoam is modelled by the Ogden compressible hyperelastic potential. A possible appearance of the shear shocks may explain the kinetic [...] Read more.
Apparently for the first time, shear shock wave fronts (shear shocks) are observed in a hyperfoam at the propagation of shear waves. The hyperfoam is modelled by the Ogden compressible hyperelastic potential. A possible appearance of the shear shocks may explain the kinetic and strain energy attenuation along with heat release at the propagation of shear waves in hyperfoams. The analysis is based on the Cauchy formalism for equations of motion, equations of energy balance, and FE analysis for solutions of the constructed nonlinear hyperbolic equation. Full article
(This article belongs to the Special Issue Computational Mathematics: Advanced Methods and Applications)
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20 pages, 7968 KiB  
Article
Horizontal PGA Estimates for Varying Deep Geological Conditions—A Case Study of Banja Luka
by Borko Bulajić, Silva Lozančić, Senka Bajić, Anka Starčev-Ćurčin, Miloš Šešlija, Miljan Kovačević and Marijana Hadzima-Nyarko
Appl. Sci. 2025, 15(12), 6712; https://doi.org/10.3390/app15126712 - 15 Jun 2025
Cited by 1 | Viewed by 508
Abstract
In this study, the city of Banja Luka is used as a case study to evaluate horizontal PGA values in regions with a history of moderate to strong earthquakes and with different deep geological conditions. We present regional attenuation equations for PGA that [...] Read more.
In this study, the city of Banja Luka is used as a case study to evaluate horizontal PGA values in regions with a history of moderate to strong earthquakes and with different deep geological conditions. We present regional attenuation equations for PGA that can capture both the impacts of deep geology and local soil conditions. A PSHA study for a site in Banja Luka was carried out using the developed empirical scaling equations and compared to all previous seismic hazard estimations for the same region. The data indicate that variations in deep geological conditions may have a greater impact on PGA values than local soil effects. Given the scarcity of scaling equations that consider deep geology in addition to local soil conditions, we believe this case study is a step toward developing more accurate PGA estimates for comparable regions. Full article
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25 pages, 9825 KiB  
Article
Noise Reduction Mechanism and Spectral Scaling of Slat Gap Filler Device at Low Angle of Attack
by Yingzhe Zhang, Peiqing Liu and Baohong Bai
Aerospace 2025, 12(6), 541; https://doi.org/10.3390/aerospace12060541 - 15 Jun 2025
Viewed by 417
Abstract
Slat noise poses a significant challenge during aircraft landing. Slat gap filler (SGF) technology has shown promise in mitigating slat noise, yet its noise reduction mechanisms and characteristics remain unclear. This study numerically investigates the noise reduction mechanisms of SGF and analyzes its [...] Read more.
Slat noise poses a significant challenge during aircraft landing. Slat gap filler (SGF) technology has shown promise in mitigating slat noise, yet its noise reduction mechanisms and characteristics remain unclear. This study numerically investigates the noise reduction mechanisms of SGF and analyzes its noise characteristics using the high-lift common research model (CRM-HL). The lattice Boltzmann solver simulates the unsteady flow field, and the Ffowcs-Williams and Hawkings (FW-H) equation predicts far-field noise. The computed results exhibit a satisfactory concordance with experimental measurements. Furthermore, the near-field flow dynamics have been elucidated through proper orthogonal decomposition. The findings demonstrate that the SGF alters the distribution patterns of flow dynamics and pressure fluctuations, thereby effectively attenuating the mode energy. Moreover, our findings demonstrate that SGF significantly reduces slat noise. The noise reduction mechanism can be attributed to decreased surface pressure fluctuations on the leading edge of the main wing, and a shifted broadband noise peak to a lower frequency due to the enlarged slat cove flow vortex caused by SGF. Finally, a scaling analysis of the slat noise spectra indicates that the SGF noise spectra align well with baseline slat noise spectra when the characteristic length scale is determined by the vortex structure. Full article
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23 pages, 4593 KiB  
Article
Laser-Induced Liquid-Phase Boron Doping of 4H-SiC
by Gunjan Kulkarni, Yahya Bougdid, Chandraika (John) Sugrim, Ranganathan Kumar and Aravinda Kar
Materials 2025, 18(12), 2758; https://doi.org/10.3390/ma18122758 - 12 Jun 2025
Viewed by 462
Abstract
4H-silicon carbide (4H-SiC) is a cornerstone for next-generation optoelectronic and power devices owing to its unparalleled thermal, electrical, and optical properties. However, its chemical inertness and low dopant diffusivity for most dopants have historically impeded effective doping. This study unveils a transformative laser-assisted [...] Read more.
4H-silicon carbide (4H-SiC) is a cornerstone for next-generation optoelectronic and power devices owing to its unparalleled thermal, electrical, and optical properties. However, its chemical inertness and low dopant diffusivity for most dopants have historically impeded effective doping. This study unveils a transformative laser-assisted boron doping technique for n-type 4H-SiC, employing a pulsed Nd:YAG laser (λ = 1064 nm) with a liquid-phase boron precursor. By leveraging a heat-transfer model to optimize laser process parameters, we achieved dopant incorporation while preserving the crystalline integrity of the substrate. A novel optical characterization framework was developed to probe laser-induced alterations in the optical constants—refraction index (n) and attenuation index (k)—across the MIDIR spectrum (λ = 3–5 µm). The optical properties pre- and post-laser doping were measured using Fourier-transform infrared spectrometry, and the corresponding complex refraction indices were extracted by solving a coupled system of nonlinear equations derived from single- and multi-layer absorption models. These models accounted for the angular dependence in the incident beam, enabling a more accurate determination of n and k values than conventional normal-incidence methods. Our findings indicate the formation of a boron-acceptor energy level at 0.29 eV above the 4H-SiC valence band, which corresponds to λ = 4.3 µm. This impurity level modulated the optical response of 4H-SiC, revealing a reduction in the refraction index from 2.857 (as-received) to 2.485 (doped) at λ = 4.3 µm. Structural characterization using Raman spectroscopy confirmed the retention of crystalline integrity post-doping, while secondary ion mass spectrometry exhibited a peak boron concentration of 1.29 × 1019 cm−3 and a junction depth of 450 nm. The laser-fabricated p–n junction diode demonstrated a reverse-breakdown voltage of 1668 V. These results validate the efficacy of laser doping in enabling MIDIR tunability through optical modulation and functional device fabrication in 4H-SiC. The absorption models and doping methodology together offer a comprehensive platform for paving the way for transformative advances in optoelectronics and infrared materials engineering. Full article
(This article belongs to the Special Issue Laser Technology for Materials Processing)
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16 pages, 5881 KiB  
Article
PGA Estimates for Vertical Ground Motion and Varying Deep Geology Site Surroundings—A Case Study of Banja Luka
by Borko Bulajić, Silva Lozančić, Senka Bajić, Anka Starčev-Ćurčin, Miloš Šešlija, Miljan Kovačević and Marijana Hadzima-Nyarko
Appl. Sci. 2025, 15(12), 6542; https://doi.org/10.3390/app15126542 - 10 Jun 2025
Cited by 1 | Viewed by 395
Abstract
Vertical PGA is frequently included in civil engineering regulations simply by multiplying the horizontal PGA by a constant. Moreover, most design codes, including Eurocode 8, do not consider the impact of the local soil on vertical ground motion at all. In this study, [...] Read more.
Vertical PGA is frequently included in civil engineering regulations simply by multiplying the horizontal PGA by a constant. Moreover, most design codes, including Eurocode 8, do not consider the impact of the local soil on vertical ground motion at all. In this study, we demonstrate that such practices increase earthquake risks. The article examines vertical PGA strong-motion estimations for the city of Banja Luka. Banja Luka serves as a case study for areas with records of moderate to strong earthquakes and diverse deep geological conditions. Regional equations for scaling vertical PGA are presented. The vertical PGA values and vertical to horizontal PGA ratios are calculated and analyzed. The findings indicate that the vertical to horizontal PGA ratios for the rock sites depend on the source-to-site distance and deep geology and fall between 0.30 and 0.66. Hence, these ratios cannot be approximated by a single value of 0.90 and 0.45, as specified by Eurocode 8 for Type 1 and Type 2 spectra, respectively. Moreover, the results show that the deep geology effects on vertical ground motion can exceed the local soil effects. When the amount of recorded data from comparable areas increases, we will be able to properly calibrate the existing scaling equations and obtain more reliable estimates of vertical PGA. Full article
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17 pages, 3610 KiB  
Article
Semi-Active Vibration Control for High-Speed Elevator Using Magnetorheological Damper
by Marcos Gonçalves, Maria E. K. Fuziki, Jose M. Balthazar, Giane G. Lenzi and Angelo M. Tusset
Magnetism 2025, 5(2), 13; https://doi.org/10.3390/magnetism5020013 - 8 Jun 2025
Viewed by 1036
Abstract
This paper presents the results of investigating the application of magnetorheological fluids in controlling the lateral and angular vibrations of a high-speed elevator. Numerical simulations are performed for a mathematical model with two degrees of freedom. The lateral and rotational accelerations are analyzed [...] Read more.
This paper presents the results of investigating the application of magnetorheological fluids in controlling the lateral and angular vibrations of a high-speed elevator. Numerical simulations are performed for a mathematical model with two degrees of freedom. The lateral and rotational accelerations are analyzed for different travel speeds to determine passenger comfort levels. To attenuate the elevator vibrations, the introduction of a magnetorheological damper in parallel with the passive damper of the elevator rollers is considered. To semi-actively control the dissipative forces of the magnetorheological fluids, a State-Dependent Riccati Equation (SDRE control) is proposed. The numerical results demonstrate that using an MR damper makes it possible to reduce the acceleration levels of the elevator cabin, thus improving passenger comfort and reducing the elevator’s vibration levels and wear on the mechanical and electronic components of the elevator. In addition to the results, a detailed sensitivity analysis is presented. Full article
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