Search Results (439)

This paper introduces a novel Magnetorheological (MR) damper integrated with a ball-screw mechanism (SMRB damper) that is designed to unify translational and rotational motions for enhanced automotive suspension performance. While shear-mode rotary MR dampers offer excellent responsiveness and stability, prior designs face persistent issues such as high off-state torque, structural complexity, or limited damping force. The proposed damper aims to overcome these limitations. Its design and operating principle are presented, followed by the development of a mathematical model based on the Bingham-plastic formulation and finite element analysis. To maximize damping capability, the key structural parameters are optimized using an Adaptive Particle Swarm Optimization (APSO) algorithm. Finally, a prototype is fabricated based on the optimized results, and experimental tests validate its performance against simulation predictions, demonstrating its improved potential for vibration control applications. Full article

Particle-laden flows in non-Newtonian fluids are encountered in a variety of industrial applications, such as concrete pumping and battery electrode slurry processing, where accurate prediction of particle migration is essential for performance and product quality. This work investigates fully developed suspension flows in circular tubes, combining the shear-induced diffusion framework of Phillips et al. with the Krieger–Dougherty relative viscosity and the Carreau–Yasuda constitutive model. Unlike previous studies that generally rely on Newtonian or simple non-Newtonian rheology models, we employ the Carreau–Yasuda model, a more sophisticated constitutive relation that captures both shear-thinning behavior and Newtonian plateau regimes. By applying nondimensionalization and variable transformations, we reduce the governing coupled differential equations to a system of nonlinear algebraic equations, which allows for efficient computation of both particle concentration and velocity profiles. A systematic parametric study was conducted to evaluate the influence of several factors, including the pressure gradient, average particle concentration, and the five parameters of the Carreau–Yasuda model. Additionally, the migration parameter $\alpha =K_c/K_{\eta }$ was considered. The results reveal how the increased rheological complexity of the Carreau–Yasuda model significantly alters the migration dynamics when compared to simpler models. These novel findings have direct implications for optimizing industrial processes involving highly loaded suspensions, offering more accurate predictions of particle behavior under varying flow conditions. For the validation of our findings, experimental data in the literature was used. Full article

Artemisinin (ART) production faces bottlenecks due to low and variable yields from its natural source, Artemisia annua. This limitation, coupled with expanding therapeutic potential beyond malaria, highlights the need for innovative production solutions. This systematic review aims to synthesize the evidence on alternative production platforms for ART. We searched PubMed, Scopus, Web of Science, and Google Scholar for studies published primarily between 2020 and 2025. Some search terms included “Artemisinin”, “Artemisia annua”, “biosynthesis”, “in vitro culture”, and “artificial intelligence”. We included primary research articles reporting on strategies for ART production. We narratively synthesized data by production theme. Our review of 30 studies identified four frontiers for ART production: (1) Enhancement in A. annua ART content; (2) In vitro platforms focusing on callus and cell suspension cultures, which offer precise control but face scale-up bottlenecks; (3) Heterologous expression in non-Artemisia plants; and (4) Scalable semi-synthetic routes using microbially fermented precursors and chemical conversion. Furthermore, the review highlights the emerging role of AI-driven predictive modeling in source discovery and process optimization. By integrating these innovations, a robust roadmap exists for sustainable ART production. Full article

This study presents a fatigue life prediction procedure for high-strength steel suspension components that exhibit surface and depth-graded mechanical properties due to manufacturing processes such as shot peening and heat treatment. A layer-by-layer approach based on local stress and material properties at the examined depth from the surface is implemented, allowing the generation of S-N curves that reflect the local fatigue response at different depths. The methodology is applied to a parabolic monoleaf spring for the axle suspension of commercial vehicles, made of 51CrV4 steel, and validated against experimental fatigue data. Results show strong agreement, demonstrating the effectiveness of incorporating local mechanical characteristics in terms of stress and material properties into fatigue design workflows. Full article

The purpose of this study was to present a chemical analysis of the metabolome of cell aggregates of the tree fern Cyathea smithii (J.D. Hooker) cell suspension culture. The LC/MS and GC/MS techniques were used for identification of metabolites. The kinetics of fresh weight, dry weight, and ash content showed 3.5-fold increases during 15-day-long culture. The analysis demonstrated high metabolic activity of cultured cells. In total, 160 metabolites from primary and secondary metabolism and almost 2000 compounds of unknown identity were identified. Three flavonoids—the chalcone isookanin [(2S)-2-(3,4-dihydroxyphenyl)-7,8-dihydroxy-2,3-dihydrochromen-4-one], a methoxy derivative of the flavone gardenin B (5-Hydroxy-2-(4-methoxyphenyl)-6,7,8-trimethoxy-4H-1-benzopyran-4-one), and the isoflavone tectoridin (4′,5-Dihydro-6-methoxy-7-(O-glucoside)isoflavone)—had not been previously detected in the cell culture of C. smithii. Principal component analysis revealed five distinct groups of samples; groups 4 and 5 showed the greatest similarity and corresponded to cultures on days 12 and 15, respectively. The number of differentiating compounds was 75, indicated by a heatmap showing positive and negative correlations between the days of culture. The studies described in this paper are crucial for further identification of metabolites and establishing the relationship between the metabolic composition of tree fern cells in culture and their biological activity, assessed by physiological parameters. By determining the relationship between the chemical composition of cells and their growth from culture initiation to senescence, we will provide a more complete picture of the potential for environmental factors to regulate this relationship. Based on previous studies, environmental stimuli such as electromagnetic fields or light of different wavelengths can result in altered growth physiology and cell mass, as well as metabolite diversification and accumulation. The research results presented in this paper provide a foundation for further studies aimed at predicting and regulating the productivity of C. smithii cells in suspension culture and elucidating the significance of tree fern-derived metabolic products in human cell biology, particularly in thyroid cells. Full article

This study has developed a novel measurement-based computational method that accurately determines the vertical and lateral wheel–rail contact forces transmitted from railway vehicles to the rails. A major contribution—and the first in the literature—is the analytical distribution of the total lateral wheelset force into its outer-wheel and inner-wheel components, thereby enabling precise individual evaluation of derailment risk on each wheel in curved tracks. Analytical equations derived from Newton’s second law were first formulated to express both vertical forces and total axle lateral force directly from bogie/axle-box accelerations and suspension reactions. To eliminate the deviations caused by conventional simplifying assumptions (neglect of creep effects, wheel diameter variation, and constant contact geometry), surrogate functions and distribution equations sensitive to curve radius, vehicle speed, and cant deficiency were introduced for the first time and seamlessly integrated into the equations. Validation was performed using the Istanbul Tramway multibody model in SIMPACK 2024x.2, with the equations implemented in MATLAB/Simulink R2024b. Excellent agreement with SIMPACK reference results was achieved on straight tracks and curves, after regression-based calibration of the surrogate functions. Although the method requires an initial regression calibration within a simulation environment, it relies exclusively on measurable parameters, ensuring low cost, full compatibility with existing vehicle sensors, and genuine suitability for real-time monitoring. Consequently, it supports predictive maintenance and proactive safety management while overcoming the practical limitations of instrumented wheelsets and offering a robust, fleet-scalable alternative for the railway industry. Full article

Magnetic levitation (Maglev) technology has long garnered significant attention in the engineering community due to its inherent advantages, such as contactless operation, minimal friction losses, low noise, and high precision. Based on electromagnetic suspension (EMS) and electrodynamic principles, these systems are primarily developed for advanced transportation, while also inspiring emerging applications such as vibration isolation and flywheel energy storage. Despite progress, practical deployment faces critical challenges, including accurate modeling, robustness against nonlinear and uncertain dynamics, and control stability under complex conditions. Artificial intelligence (AI), particularly machine learning (ML) offers promising solutions. Studies show ML-based methods, i.e., improved particle swarm optimization (PSO) optimize proportional-integral-derivative (PID) to reduce controller output overshoot, deep reinforcement learning (DRL) reduces levitation gap fluctuation under complex conditions, ensemble learning achieves high fault diagnosis accuracy, and convolutional neural network-long short-term memory (CNN-LSTM) predictive maintenance cuts costs. This review summarizes recent AI-enabled advances in Maglev transportation system modeling, control, and optimization, highlighting representative algorithms, performance comparisons, technical challenges, and future directions toward intelligent, reliable, and energy-efficient transportation systems. Full article

Flow regimes of vertical upflow for slightly cohesive Geldart A powders at high solids mass flux ($G_s$$\gtrsim$ 500 kg/m²s) are not fully resolved. In particular, Dense Suspension Upflow (DSU) as a distinct flow regime and its transition boundaries are not broadly accepted. Furthermore, the locus of the pressure gradient minimum, which is the broadly accepted dense–dilute transition at low $G_s,$ requires validation at high $G_s$. In our recent work, by adapting the phase map of Wirth and by Eulerian modeling, DSU was defined as a distinct flow regime with gross upflow of solids and with granular temperature at the wall greater than that in the bulk. This study has further validated the definition of DSU and its transition boundaries by extending the modeling to areas not fully explored in the earlier work. Furthermore, this study has identified (a) the possibility of a phase of DSU between fast fluidization and turbulent regime at all $G_s$; and (b) the need to review the suitability of the locus of the pressure gradient minimum as the dense–dilute transition at high $G_s$. Additionally, our work has demonstrated (a) a new provisional correlation that the upper transport velocity for Geldart A powders is significantly greater than hitherto predicted; and (b) the slip velocity in the transport regimes increases with $G_s$ to peak within fast fluidization and falls thereafter to attain low multiples of the terminal settling velocity within DSU. Full article

Background/Objectives: Baihe Dihuang Tang (BDT), a classical herbal formula from Zhang Zhongjing’s Han Dynasty work Jin Gui Yao Lue, is widely used to treat depressive disorder by nourishing Yin, clearing heat, and tonifying the heart and lungs. However, its pharmacological mechanisms remain unclear. This study aims to explore BDT’s antidepressant effects via MAOA-regulated serotonin (5-HT) metabolism and synaptic plasticity, supported by experimental validation, while using network pharmacology to predict MAOA-targeting active components. Methods: Active components and targets of BDT were screened using TCMSP, TCMID, and other databases, and then a component-target-pathway network was constructed. A chronic restraint stress (CRS)-induced depressive mouse model was established. Behavioral tests, including open field test (OFT), elevated plus maze (EPM), forced swimming test (FST) and tail suspension test (TST), were conducted to evaluate antidepressant effects. ELISA, qRT-PCR, and Western blot were employed to assess hippocampal 5-HT metabolism (MAOA, 5-HT/5-HIAA ratio) neurotrophic signaling (BDNF, TrkB) and synaptic plasticity-related proteins (PSD-95, SYN1). Results: BDT significantly reduced FST/TST immobility time and improved anxiety-like behaviors in OFT/EPM. BDT treatment downregulated MAOA expression, elevated hippocampal 5-HT/5-HIAA ratio, activated BDNF/TrkB pathway, and upregulated PSD-95/SYN1. Network pharmacology confirmed MAOA’s central role, identifying MAOA/serotonergic synapse modulation as BDT’s main mechanism and pinpointing Ferulic acid, Caffeate, Stigmasterol, (−)-nopinene, Eugenol, and cis-Anethol as MAOA-targeting bioactive components. Conclusions: BDT ameliorates depressive-like behaviors. This effect is mechanistically linked to suppression of MAOA-mediated 5-HT catabolism—a key validated target. This suppression elevates hippocampal 5-HT bioavailability, thereby activating BDNF/TrkB signaling and promoting synaptic plasticity. Network pharmacology confirmed MAOA as a primary target and identified specific modulatory bioactive components. Full article

The periodontal ligament (PDL) is essential for the physiological mobility and load distribution of natural teeth, yet its simulation in mechanical testing remains inconsistent and insufficiently standardized. The absence of a resilient suspension system can alter force transmission, affect failure patterns, and reduce the clinical relevance of in vitro outcomes. This study aimed to develop a reproducible CAD/CAM-based model for PDL simulation that provides elastic suspension of a tooth replica under laboratory conditions. A digitally defined offset was applied around a tooth replica to create a controlled PDL space, which was filled with polyether. To ensure precise seating of the specimens, a 3D-printed positioning device was used. Functional calibration was performed using Periotest measurements to identify the offset that reproduced physiological tooth mobility. A digital offset of 0.85 mm produced a radiographically confirmed polyether layer of 0.86 ± 0.05 mm and yielded Periotest values comparable to natural teeth in the horizontal direction (mean PTV = 2.99 ± 0.92). Vertical measurements demonstrated higher damping (mean PTV = −4.02 ± 0.56), consistent with the anisotropic behavior of natural PDL. The model showed high fabrication accuracy and predictable mechanical behavior, providing a physiologically relevant method for incorporating PDL simulation into laboratory mechanical testing. Full article

This study investigates the influence of suspension elastokinematics on vehicle handling and stability through a combined research of experimental testing and numerical simulation. Laboratory tests were conducted on the front suspension of a Mercedes-Benz S320 using a quarter-car test rig equipped with specialized sensors to measure wheel displacements, steering angles, camber, and accelerations. Complementary dynamic tests were carried out under real driving conditions, including braking in a turn and “fishhook” maneuvers, to capture suspension behavior under critical operating scenarios. Based on the experimental data, an MSC Adams/Car multibody simulation model was used, incorporating varying stiffness values of suspension elastomeric elements that replicated progressive aging and degradation effects. The simulation results were compared with experimental data to validate the model’s predictive capability. Key findings indicate that reductions in elastomer stiffness significantly affect wheel kinematics, vehicle yaw response, and lateral acceleration, particularly during high-intensity maneuvers. The results underline the critical importance of accounting for elastomeric component degradation in suspension modeling to ensure vehicle safety and performance over the operational lifespan. The developed methodology demonstrates the effectiveness of integrating experimental measurements with advanced simulation tools to assess elastokinematic effects on vehicle dynamics. Full article

A sediment suspension model is established to predict the sediment movement beneath asymmetric waves, in which the bottom boundary condition for the sediment concentration equation is specified by means of pickup function parameterized by a modified model of the bottom shear stress. The modified model of the bottom shear stress involves velocity and acceleration processes as well as the phase difference between the near-bed orbital velocity and bottom shear stress. Moreover, the phase difference is not a constant in one wave cycle but different in the durations of positive and negative velocities. And the phase differences are parameterized into a function that is dependent on the degree of wave asymmetry based on plenty of numerical data of the boundary layer obtained by large eddy simulation (LES) of oscillatory boundary layer flows. The bottom shear stress calculated by the modified model is compared with those obtained from both the experiments and the LES model, demonstrating that the modified model can capture the unsteady characteristics of the bottom shear stress beneath asymmetric waves accurately. Then, the proposed sediment suspension model is coupled with a numerical wave flume so as to obtain the progressive wave fields and the suspended sediment movement. The velocity and sediment concentration of both reduced- and large-scale hydrodynamic conditions calculated by the coupled model are compared with experimental data with a good agreement, suggesting reliability of the proposed model to predict sediment transport induced by asymmetric waves. Full article

This paper presents a case study on an ultra-deep excavation in a reclaimed area supported by servo steel struts, addressing the limited case-specific data on deformation behavior under such complex geological conditions. Comprehensive monitoring of the pit structure and surrounding environment was performed throughout construction. Results highlight significant time-dependent deformation due to the rheological behavior of artificial fill and soft soil, with metro tunnel displacement during suspension phases contributing up to 29% of the total. Servo steel struts, via active axial force compensation, reduced maximum diaphragm wall displacement by 24%, ground settlement by 29%, and pipeline settlement by 46% compared to conventional supports. Integrated measures, including bottom-sealed diaphragm walls, isolation piles, and grouting curtains, successfully confined tunnel deformation within 5.4 mm, complying with strict safety criteria. A strong linear correlation between tunnel and wall displacements was observed, enabling a predictive envelope model for deformation. This study underscores the efficacy of servo steel struts in controlling excavation-induced deformation in reclaimed areas and offers practical insights for designing and managing ultra-deep excavations in similar challenging settings. Full article

Gravitational waves (GW) play an important role in the understanding of several astrophysical objects, like neutron stars and black holes. One technology used to detect them involves massive objects that vibrate as GW cross it, and the detectors built are, accordingly, of the resonant-mass type. SCHENBERG is a resonant-mass GW detector, built in Brazil, whose antenna is a spherical, 65 cm in diameter mass made of a CuAl alloy, and its quadrupole vibrational modes would be excited by GW, as predicted by general relativity. The chosen alloy can be cooled down to mK temperatures with a good mechanical quality factor. The quadrupole mode frequencies were measured at 4K, and a frequency band of about 67.5 Hz was found, but when the antenna was simulated in SolidWorks FEM software version 2010–2011 (as well as in Ansys SpaceClaim^TM), the band obtained for a free sphere was different—around 30 Hz. When the holes for the suspension were included in the simulation, the same discrepancy persisted. In this work, gravity was included in the FEM simulation, and we show that the bandwidth results are even smaller. We were then able to obtain a bandwidth close to the measured one by including a small deviation from the vertical axle, as well as variations on the sphere microstructure, which are assumptions that break the symmetry of a perfect, homogeneous free sphere. We believe that the microstructure variations are due to differences in the cooling time during the sphere casting. As for a good mechanical quality factor, the sphere was not submitted to homogenization. With these additions to the FEM simulation, a reasonable frequency distribution was found, consistent with the one measured for SCHENBERG’s antenna. Full article

The central purpose of this study is to develop and validate an advanced numerical model capable of simulating the vibrational behavior of the operator’s seat in a tractor-type agricultural vehicle designed for operation in protected horticultural environments, such as vegetable greenhouses. The three-dimensional (3D) model of the seat was created using SolidWorks 2023, while its dynamic response was investigated through Finite Element Analysis (FEA) in Altair SimSolid, enabling a detailed evaluation of the natural vibration modes within the 0–80 Hz frequency range. Within this interval, eight significant natural frequencies were identified and correlated with the real structural behavior of the seat assembly. For experimental validation, direct time-domain measurements were performed at a constant speed of 5 km/h on an uneven, grass-covered dirt track within the research infrastructure of INMA Bucharest, using the TE-0 self-propelled electric tractor prototype. At the operator’s seat level, vibration data were collected considering the average anthropometric characteristics of a homogeneous group of subjects representative of typical tractor operators. The sample of participating operators, consisting exclusively of males aged between 27 and 50 years, was selected to ensure representative anthropometric characteristics and ergonomic consistency for typical agricultural tractor operators. Triaxial accelerometer sensors (NexGen Ergonomics, Pointe-Claire, Canada, and Biometrics Ltd., Gwent, UK) were strategically positioned on the seat cushion and backrest to record accelerations along the X, Y, and Z spatial axes. The recorded acceleration data were processed and converted into the frequency domain using Fast Fourier Transform (FFT), allowing the assessment of vibration transmissibility and resonance amplification between the floor and seat. The combined numerical–experimental approach provided high-fidelity validation of the seat’s dynamic model, confirming the structural modes most responsible for vibration transmission in the 4–8 Hz range—a critical sensitivity band for human comfort and health as established in previous studies on whole-body vibration exposure. Beyond validating the model, this integrated methodology offers a predictive framework for assessing different seat suspension configurations under controlled conditions, reducing experimental costs and enabling optimization of ergonomic design before physical prototyping. The correlation between FEA-based modal results and field measurements allows a deeper understanding of vibration propagation mechanisms within the operator–seat system, supporting efforts to mitigate whole-body vibration exposure and improve long-term operator safety in horticultural mechanization. Full article