Search Results (2,172)

To address the longitudinal vibration issues in high-speed elevators induced by external excitations, this study constructs a high-precision multi-degree-of-freedom (MDOF) dynamic model to systematically analyze vertical dynamic response characteristics. Utilizing the substructure method, the complex traction system is decomposed into several subsystems, including the traction device, tensioning device, car and car frame, counterweight system, and segmented wire ropes. By integrating Lagrange’s equations with Newton’s second law, the governing differential equations of motion for each component are derived, establishing an adaptable global dynamic model. The forced vibration analysis focuses on the impacts of periodic excitation from traction sheave eccentricity, piecewise reverse braking torque, and vertical impacts from guide rail joints on car vibration response and wire rope dynamic stress. The results indicate that: traction sheave eccentricity leads to periodic fluctuations in car acceleration, with vibration peaks decreasing as the payload increases; reverse braking torque triggers impulsive acceleration overshoots, where the peak value under full-load conditions increases by approximately 15% compared to the no-load condition, accompanied by a longer duration of low-frequency vibrations; guide rail joint impacts produce instantaneous acceleration spikes, which increase by about 18% under high-speed operating conditions; and the wire rope stress exhibits significantly higher sensitivity to load variations within the low-load range of 0–0.2. Full article

Rectangular sinking wells are widely used in underground and hydraulic engineering, where maintaining vertical alignment during construction is essential for safe serviceability and long-term performance. Even moderate inclination may cause eccentric transfer of the vertical load to the concrete plug, leading to non-uniform contact stresses beneath the base. This study presents a closed-form analytical framework for assessing the admissible tilt of rectangular sinking wells based on stress redistribution under one-axis inclination. The well is modeled as a rigid body, and the resulting load eccentricity is related to the shaft height and tilt angle. Classical eccentric compression theory is then used to derive explicit expressions for the maximum and minimum base stresses, from which a serviceability-based admissibility criterion is formulated. The obtained solution provides the allowable inclination directly as a function of shaft height, plan dimensions, and an adopted stress amplification factor. Parametric analyses show that the admissible tilt decreases with increasing shaft height and increases with larger base dimensions. A distinct directional anisotropy is observed for rectangular plans, whereas square wells recover symmetric behavior with identical limits in both orthogonal directions. This identifies square geometry as the symmetry-preserving limit case of the proposed model. Sensitivity analyses further demonstrate the influence of admissible stress amplification on permissible inclination levels. The proposed formulation offers a transparent screening tool for construction monitoring and post-construction assessment, while also illustrating how geometric symmetry reduction governs the mechanical response of inclined foundation systems. Full article

The middle Eocene represents a shift from the Early Eocene greenhouse climate to a subsequent cooling trend, during which orbital-scale forcing exerted a strong influence on continental depositional systems. The third Member of the Hetaoyuan Formation (Eh₃) in the Biyang Depression of the Nanxiang Basin preserves a thick lacustrine succession, but its third-order sequence subdivision has remained controversial because of insufficient temporal control. In this study, natural gamma-ray (GR) logs from wells A1 and A2 were analyzed using an integrated workflow that combines cyclostratigraphy, INPEFA (Integrated Prediction Error Filter Analysis), wavelet transform, and sedimentary noise modeling. The GR records reveal clear astronomical signals corresponding to ~405 kyr long eccentricity, ~100 kyr short eccentricity, ~40 kyr obliquity, and ~20 kyr precession. Astronomical tuning to the 405 kyr cycle yields a depositional duration of ~10.3 Myr and a basal age of ~49.6 Ma. Integrated stratigraphic analysis identifies nine third-order sequence boundaries and eight third-order sequences. In addition, sedimentary noise modeling detects a prominent ~1.2 Myr long-period obliquity modulation signal, which is interpreted to govern long-term lake-level fluctuations and third-order sequence development. These results provide a time-constrained framework for sequence subdivision and demonstrate the importance of orbital forcing in shaping lacustrine stratigraphic architecture. Full article

On behalf of the Strength and Conditioning Society (SCS), we are pleased to present the abstracts submitted for the SCS 8th Annual Meeting. The event was held at the Norwegian School of Sport Sciences in Oslo, Norway, on 8–10 October 2025, and comprised several invited sessions held by international and national speakers on a variety of topics related to biochemistry and exercise physiology, strength and conditioning practices and their application to health, injury prevention, and sports performance. These included strength training in high-performance sports, sport science and training–competition load management in elite environments, biochemistry and exercise physiology and prescription, nutrition and biomechanics, among others. The conference also included practical workshops held by renowned academics and practitioners on eccentric training, change of direction ability, and strength and power training in professional team sports, combat sports, and ergospirometry and exercise prescription in specific populations. Finally, the event disseminated up-to-date strength and conditioning research by providing practitioners and researchers with the opportunity to present their most recent findings. All abstracts presented at the SCS 8th Annual Meeting can be found in this Conference Report. Full article

Considerable progress has been made in predicting nominal NVH behavior in electric drivetrains, but the acoustic scatter observed across manufactured units remains insufficiently understood. In practice, nominally identical drive units may still exhibit noticeably different tonal behavior because small deviations in gears, shafts, bearings, fits, centering features, or assembly phase modify the excitation, transfer, and radiation mechanisms of the system. This review examines how manufacturing and assembly variability influences NVH performance in electric drive units and e-axles, with particular focus on the rotor–shaft–gear–bearing–housing system. Unlike broader EV NVH reviews, the present work focuses specifically on variability-induced acoustic scatter and its propagation along the drivetrain NVH generation and transmission path. To support transparency and consistency, the literature search and selection process followed a structured, PRISMA-inspired approach across Scopus, Web of Science, Google Scholar, and SAE Mobilus for the 2015–2026 period. From 387 identified records, 50 studies were retained after duplicate removal, screening, and full-text assessment. The selected literature was synthesized into eight thematic categories: imbalance; run-out and eccentricity; bearing clearance and preload; spline and pilot centering; thermal effects; phase indexing; transmission error and sidebands; and end-of-line NVH diagnostics. The reviewed literature shows that manufacturing- and assembly-induced deviations can significantly alter transmission error, sideband structure, shaft-order content, and final tonal response, even when individual components remain within nominal tolerance limits. Beyond synthesizing the evidence base, the review organizes existing modeling and diagnostic practices into a structured framework for variability-aware NVH assessment, based on explicit deviation parameterization, hierarchical model fidelity, intermediate excitation metrics, thermal-state awareness, and closer integration with production and measurement data. Overall, the findings support a shift from nominal NVH assessment toward robustness-oriented, production-representative interpretation and future prediction of acoustic scatter in electric drivetrains. Full article

The L-shaped columns of recycled aggregate concrete-filled steel tubes (L-RACFSTs) with a 40% coarse aggregate replacement ratio were selected as the research subject, and axial compression and eccentric compression tests were conducted. Based on validated finite element numerical simulation methods, a parametric analysis was carried out, incorporating key parameters such as steel strength, width-to-thickness ratios of the square steel tube and connecting plate, and load eccentricity. The mechanical properties of L-RACFSTs under axial compression and eccentric compression loads were studied. The results show the following: (1) At a 40% replacement rate, axial compression specimens exhibited obvious in-plane deformation of the column limbs, whereas eccentric compression specimens showed overall bending toward the inner side of the column. (2) As the strength of the steel increases, the axial and eccentric compressive bearing capacities of the specimens gradually increase. It is recommended that structural steel with a strength grade of Q355 is adopted. (3) When the width of a square steel tube is fixed, the axial and eccentric compressive bearing capacities of the test specimen gradually increase as the width-to-thickness ratio decreases. (4) In contrast, for a connecting plate of a fixed width, an increase in the width-to-thickness ratio results in a decrease in bearing capacity. Additionally, due to the increased width of the connecting plate, bearing capacity will decrease in some cases. (5) The bearing capacity under eccentric loading decreases gradually as the eccentricity increases; it is recommended that the eccentricity be kept below 120 mm. Full article

In this work, using the simulator VPLanet, we analyze the spin evolution of some selected exoplanets due to the tidal interaction with their host star. For a rocky planet, two spin “conditions” are possible, the “trapped” rotation and the “fast” rotation, referring to the cases of achieved and non-achieved tidal trapping, respectively. We focus on planets whose spin condition is not obvious, because no study is needed for planets which are undoubtedly fast rotators or undoubtedly trapped rotators; moreover, we consider only exoplanets that are interesting from an astrobiological perspective. The current spin conditions of the considered planets are hypothesized, taking into account the age of the host star. Inferences regarding planetary climate and habitability—which is defined by the possibility of stably sustaining the liquid water on the surface—are also discussed. Results of this work show that Kepler-62f, Kepler-1126c, and Kepler-1544b are expected to be fast rotators regardless of the orbital eccentricity; the spin condition of Kepler-186f, Kepler-62e, and Kepler-442b cannot be determined without constraints on the eccentricity, which are currently unavailable; Kepler-440b is expected to be tidally trapped. Full article

According to investigation, the wheelset generally appears in a mass eccentric condition. Therefore, the finite element model of a wheelset–track system with mass eccentricity was established in this study to investigate the dynamic response characteristics based on the frictional self-excited vibration theory. The research results show that, when the frictional self-excited vibration of the wheelset–track system occurs, the unstable vibration characteristics of the wheelset–track system corresponding to different dynamic imbalance values are almost the same. That is, the magnitude of the dynamic imbalance value has little influence on the frictional self-excited vibration of the wheelset–track system. Simultaneously, from the perspective of the excitation frequency f of the wheel polygonal wear, it shows a trend of increasing frequency with an increase in the running speed. Ultimately, as the phase difference in mass eccentricity grows, pronounced instability becomes evident within the mid- to high-frequency ranges once friction-induced self-excitation arises in the wheelset–track system. This condition readily promotes high-order polygonal wear on the wheel surfaces. Full article

Background: Targeted training interventions, including neuromuscular warm-up protocols, eccentric resistance training, and dynamic stretching exercises, with limited and heterogeneous evidence on recovery strategies, have shown potential benefits for muscle performance and reductions in injury risk. Objective: To synthesize and structure contemporary evidence on exercise-based interventions spanning the pre-activity warm-up through post-activity recovery, emphasizing performance outcomes, injury-related effects, reported dose–response patterns, and implementation characteristics. Methods: This systematic review with structured qualitative synthesis was based on a systematic database search and eligibility screening process (n = 40 studies). Studies evaluating exercise-based interventions targeting injury prevention and/or performance in athletes were included. Data extraction included study design, population characteristics, intervention components, outcomes, and risk-of-bias assessments, which were summarized using comparative tables and descriptive analyses. Due to heterogeneity, results were synthesized qualitatively without meta-analysis. Results: Neuromuscular warm-ups (e.g., FIFA 11+) were frequently linked to reduced reported lower-extremity injury risk, alongside improvements in sprint, jump, and balance performance. Eccentric hamstring training was linked in several studies to lower reported hamstring injury rates and increased eccentric strength and fascicle length, while dynamic warm-ups may acutely improve sprint and jump performance. Evidence regarding recovery modalities was heterogeneous, supporting a cautious and individualized emphasis on sleep, nutrition, and hydration. However, heterogeneity in study designs, outcome measures, and populations limits the comparability and generalizability of the findings. Conclusions: Exercise-based interventions, including neuromuscular warm-ups, eccentric strengthening, dynamic stretching, and progressive load and recovery strategies, may support performance enhancement and injury-risk reduction in youth and adult athletes when appropriately implemented, although interpretation is limited by study heterogeneity. Full article

Background: Distinguishing functional dystonia (FD) from idiopathic dystonia (ID) remains a major clinical challenge because both conditions are diagnosed primarily on clinical grounds and may be accompanied by non-motor psychiatric symptoms. Although personality abnormalities have been described in functional neurological disorders, their relevance in the differential diagnosis of dystonia remains insufficiently studied, and comparative data on FD and ID are lacking, particularly in the Russian population. Patients and Methods: A total of 178 patients with idiopathic dystonia (focal and segmental dystonia, ID) and 32 patients with functional dystonia (FD) were observed. A clinical interview by a psychiatrist was conducted; the SCID-II-PD questionnaire and the Five-Factor Personality Questionnaire (5-PFQ) were used to assess PD. Results: Patients with FD more often than patients with ID had such PD as dependent, paranoid, passive–aggressive, borderline, schizoid and schizotypal (p < 0.001), as well as obsessive–compulsive (p < 0.013) and avoidant (p < 0.049) according to SCID-II-PD. In FD, personalities of the eccentric cluster A predominate; patients with FD are characterized in personality terms by significantly greater introversion, detachment, naturalness (irresponsibility, impulsivity, carelessness), emotional restraint and practicality (conservatism, low sensitivity, rigidity) according to 5-PFQ. Conclusions: Patients with FD differ from patients with ID in both categorical and dimensional personality characteristics. The predominance of cluster A personality pathology and the identified pattern of personality-related variables may have potential value as adjunctive markers in the clinical differentiation of FD from ID. Further external validation is required before these findings can be incorporated into diagnostic algorithms. Full article

Big Bang theories are connected to gravity by force of attraction. Forced lengthening, like eccentric contractions, instigate proprioception as a result of working against gravity. Piezo2, as the principal mechanosensory ion channel responsible for proprioception, is theorized to fine-modulate these anti-gravitational contractions in order to provide system-wide ultrafast postural control. This mechanism may instantaneously emit energy and force through Piezo2 in order to offset gravity by anti-gravity entropic-spring-like stochastic mechanics and it is suggested to be propagated by quantum tunneling of protons (and electrons). However, a Piezo2-initiated wormhole-like mechanism with the contribution of cryptochromes should be considered as part of this ultrafast long-distance non-synaptic neurotransmission, although the quantum gravity concept is short of being unequivocally proven to be unified with quantum theory. The impairment of this theoretical ultrafast signaling is analogous to a Big Bang-like mechanism within a given compartment, or acquired Piezo2 channelopathy, leading to the principal gateway to pathophysiology. Full article

Reliable fault detection in brushless DC motors is challenging owing to environmental complexity and high equipment costs. To address these challenges, we propose an effective and cost-effective approach using an optimized end-to-end one-dimensional convolutional neural network. Specifically, a real experimental platform simulating bearing and eccentricity faults was developed. Statistical t-tests indicated that three-axis accelerometer signals from a low-cost inertial measurement unit provided sufficient fault information for the present diagnosis task. Unlike traditional methods such as support vector machines, multilayer neural networks, and random forests, which rely on manual feature extraction, our model learns directly from raw waveforms and can handle signal drift. Under the present controlled experimental setting and the leave-one-day-out evaluation protocol, the model achieved 100.00% average window-level classification accuracy, considerably outperforming traditional methods, the performances of which declined to 67.95–71.37% under environmental shifts. Moreover, with an inference time of only 0.96 ms, 32 times faster than that of random forests, this approach is well suited for real-time embedded monitoring. The proposed method demonstrates strong potential for cost-efficient and robust fault diagnosis under the present experimental setting. Full article

The purpose of the present study was to examine whether countermovement vertical jump (CMJ) force-time metrics differ among teams with three ranking statuses competing within the same professional women’s handball league in Europe (i.e., SuperLeague). Following a standardized dynamic warm-up procedure, twenty-six professional female handball players (top-ranked: n = 8; mid-ranked: n = 8; bottom-ranked: n = 10) performed three CMJs on a uni-axial force plate sampling at 1000 Hz (VALD Performance). Nineteen force-time metrics were derived to characterize neuromuscular performance qualities during both the eccentric (i.e., braking) and concentric (i.e., propulsive) phases of the jumping motion. A one-way ANOVA revealed no statistically significant differences (p < 0.05) between the teams for any CMJ force-time metric of interest (i.e., peak and mean eccentric force and power, jump height, reactive strength index-modified, countermovement depth, eccentric and concentric duration) across ranking status in either phase of the movement, nor for anthropometric characteristics (i.e., height and body mass). Overall, the results indicate that CMJ force-time metrics did not differentiate team ranking status within this sample of professional female handball players. These findings suggest that, within a homogeneous cohort competing at the same level of play, CMJ-derived neuromuscular performance characteristics may have limited sensitivity for distinguishing between teams of different competitive rankings. While CMJ force-time analysis remains a useful tool for monitoring individual neuromuscular status, the present results do not allow conclusions regarding the role of other performance determinants (e.g., tactical or technical factors), which were not directly assessed in this study. Full article

Background/Objectives: Gated cardiac positron emission tomography (PET) synchronizes PET data to the cardiac cycle based on an electrocardiogram (ECG) signal, providing left ventricular (LV) functional and geometrical parameters. Nevertheless, image artifacts, due to cardiac-, breathing-, and/or patient-motion occurring during image acquisition, undermine the reliability and clinical utility of these parameters. This study aims to elucidate the effect of two motion correction (MC) tools, CardioFreeze (CF) and a data-driven motion correction (DDMC) prototype, on LV functional and geometrical parameters. Methods: ECG-gated rest/stress [¹³N]NH₃ PET/CT scans from forty patients with myocardial ischemia and thirty-nine patients with normal myocardial perfusion were included. The following four reconstructions were performed for each patient scan: without motion correction (NMC), with CF, DDMC, and DDMC & CF. Images were processed with Cedars-Sinai QPET software. Results: End-diastolic volume (EDV) in rest and stress increased significantly using DDMC. End-systolic volume (ESV) increased significantly, while LV ejection fraction (LVEF) decreased significantly using any MC tool, regardless of the phase. Shape index end-systole (SI ES) and shape-index end-diastole (SI ED) increased significantly when using MC, except for SI ED in rest, where DDMC did not cause any difference. Eccentricity index end-systole (ECC ES) in rest and stress increased significantly in patients with normal myocardial perfusion, while it did not differ in ischemic patients after applying MC. Conclusions: MC tools significantly increase ESV values and decrease EF values. The highest effect is observed with the combined use of DDMC & CF. Image quality is greatly improved when using MC, regardless of the method, particularly in patients with the highest myocardial displacement. Full article

Objective: To analyze the relationship between weekly accumulated external load and pre-match neuromuscular performance assessed through the countermovement jump (CMJ), in under-21 (U21) football players across 10 competitive microcycles. Methods: Sixteen U21 football players (age: 18.9 ± 0.42 years; height: 180 ± 6.3 cm; body mass: 78.5 ± 8.5 kg) from a Chilean professional club were monitored over 10 consecutive weeks. In each microcycle, the relationship between changes in neuromuscular performance estimated from CMJ-derived variables and two components of external load was analyzed: (1) weekly accumulated external load and (2) the acute–chronic workload ratio (ACWR). External load variables included total distance (TD), high-speed running distance (HSR), accelerations (ACC), decelerations (DC), and PlayerLoad (PL). CMJ variables included jump height (JH), modified reactive strength index (RSI-mod), and peak eccentric velocity (PEV). Performance changes were calculated as the percentage change (Δ%) between MD + 2 (start of the microcycle) and MD − 1 (pre-match). Pearson or Spearman correlation coefficients were applied depending on data distribution. Results: Significant negative associations were observed between weekly accumulated external load and changes in CMJ performance. Reductions in JH were associated with TD, HSR, ACC, and PL. Similar patterns were found for RSI-mod, while PEV showed a particularly strong association with ACC. Additionally, ACWR demonstrated significant negative relationships with CMJ changes, especially for HSR, ACC, and PL. Conclusions: Higher weekly accumulated external loads and elevated ACWR, particularly in high-intensity metrics such as high-speed running and accelerations, are associated with impaired pre-match neuromuscular performance. Consequently, monitoring CMJ-derived variables alongside external load data is recommended to manage fatigue and optimize match readiness in young football players. Full article