Search Results (105)

Background/Objectives. Despite growing interest in capacitive-resistive electric transfer TECAR) and Vibration therapy (VT), their comparative effectiveness in sports recovery remains unclear. This study aimed to evaluate and contrast the short-term effects of TECAR and VT on neuromuscular recovery following eccentric muscle fatigue, relative to passive rest, in active young adults. We hypothesized that both interventions would accelerate recovery and potentially reduce injury risk. Methods. Forty-one participants were randomized into two groups: TECAR therapy (Group 1) and VT (Group 2). Neuromuscular function was assessed at baseline, post-exercise, and post-intervention using tensiomyography (TMG) and electromyography (EMG). Results. Both groups showed a significant increase in EMG MDF intercept after exercise. Post-intervention, VT induced a further rise in this parameter, whereas TECAR stabilized values without significant change. In the contralateral resting limb, increases persisted after exercise and passive recovery. Between-limb differences were significant only in the TECAR group. TMG analysis revealed a non-significant but large-effect increase in contraction delay (Td) post-exercise, followed by significant reductions after both interventions. In the left limb, Td changes were not significant. For maximal displacement (Dm), both VMO and VLO muscles demonstrated a significant decrease post-exercise and a marked recovery after both therapies. Other TMG parameters (Ts, Tc, Tr) showed no significant changes. Conclusions. Both TECAR and VT effectively enhanced neuromuscular recovery after eccentric exercise. TECAR demonstrated a modest but consistent advantage, particularly in normalizing muscle recruitment and restoring mechanical properties, making it suitable in contexts requiring rapid recovery. VT, however, remains a more accessible and cost-effective modality. These findings support the application of both techniques in sports recovery, while highlighting the need for further research in professional athletes and diverse exercise settings to optimize regeneration strategies and reduce injury risk. Full article

A simple analytic procedure for the linear static analysis of short thin-walled beams with monosymmetric open cross-sections subjected to eccentric axial loading is presented. Under eccentric compressive loading, the beam is subjected to compression/extension, to torsion with influence of shear with respect to the principal pole and to bending with influence of shear in two principal planes. The approximate closed-form solutions for displacements consist of the general Vlasov’s solutions and additional displacements due to shear according to the theory of torsion with the influence of shear, as well as the theory of bending with the influence of shear. The internal forces and displacements for beams clamped at one end and simply supported on the other end, where eccentric loading is acting, are calculated using the method of initial parameters. The shear coefficients for the monosymmetric cross-sections introduced in these equations are provided. Solutions for normal stress and total displacements according to Vlasov’s general thin-walled beam theory, and those obtained with the proposed method taking shear influence into account, are compared with shell finite element solutions analyzing isotropic and orthotropic I-section beams. According to the results for normal stress relative differences, and Euclidean norm for displacements, it has been demonstrated that shear effects must be accounted for in the analysis of such structural problems. Full article

This study presents a machine learning-based framework for predicting the electrical output of a vibration energy harvesting system (VEHS) integrated with a Jeffcott rotor model. Vibration induced by rotor imbalance is converted into electrical energy via piezoelectric elements, and the system’s dynamic response is simulated using the fourth-order Runge–Kutta method across varying mass ratios, rotational speeds, and eccentricities. The resulting dataset is validated experimentally with a root-mean-square error below 5%. Three predictive models—Deep Neural Network (DNN), Long Short-Term Memory (LSTM), and eXtreme Gradient Boosting (XGBoost)—are trained and evaluated. While DNN and LSTM yield a high predictive accuracy (R² > 0.9999), XGBoost achieves comparable accuracy (R² = 0.9994) with significantly lower computational overhead. The results demonstrate that among the tested models, XGBoost provides the best trade-off between speed and accuracy, achieving R² > 0.999 while requiring the least training time. These results demonstrate that XGBoost might be particularly suitable for real-time evaluation and edge deployment in rotor-based VEHS, offering a practical balance between speed and precision. Full article

Background: Physical exercise can improve certain musculoskeletal conditions, but adherence remains low due to intimidating environments, limited government support, and financial constraints faced by many individuals. Home-based exercise is a potential strategy to treat that population. Objective: Discuss the main home-based resistance exercise protocols that have been studied and implemented for six highly prevalent musculoskeletal disorders. Methods: A narrative literature review was conducted, using the PubMed database to search for six highly prevalent musculoskeletal conditions: shoulder impingement syndrome (SIS), nonspecific low back pain (NSLBP), greater trochanteric pain syndrome (GTPS), knee osteoarthritis (OA), patellofemoral pain syndrome (PFPS), and Achilles tendinopathy (AT). The strategy included the listed pathologies and the keywords “physical exercise” or “physiotherapy”. Clinical trials, reviews, and retrospective studies from the last 30 years published in English, Portuguese, or Spanish were included. Only studies with sufficient details on the training protocols used and outcome measures were included in the analysis. Results: In SIS, exercise protocols have been more effective in the long term than in the short term. In PFPS and GTPS, strengthening the quadriceps and hip muscles helps reduce pain and improve function. For NSLBP, exercises like Pilates and core training demonstrate pain relief. In knee osteoarthritis, physical exercise improves pain, function, and quality of life both immediately and over time. Eccentric training promotes type I collagen formation in the tendons of patients with Achilles tendinopathy. Conclusions: Home-based resistance exercises studied and implemented in this review offer several general health benefits, including pain reduction, improved functionality, increased muscle strength, and enhanced motor control. Full article

To enhance the environmental sustainability and structural performance of concrete-filled steel tubes (CFSTs), this study experimentally investigates the eccentric compression behavior of short CFST columns incorporating alkali-activated concrete (AAC) and internal stiffeners. Fifteen specimens were tested, varying in steel tube thickness, stiffener thickness, and eccentricity. The results show that increasing eccentricity reduces load-bearing capacity and stiffness, while stiffeners delay local buckling and improve stability. Based on the experimental findings, the applicability of the GB 50936-2014, Design of Steel and Composite Structures Specification, and the American AISC-LRFD specification to the design of ACFST columns is further evaluated. Corresponding design recommendations are proposed, and a regression-based predictive model for eccentric bearing capacity is developed, showing good agreement with the test results, with prediction errors within 10%.providing technical references for the development of low-carbon, high-performance CFST members. Full article

Strength training has established itself as an essential component in physical conditioning programmes, not only to improve sports performance, but also for health purposes. To evaluate the effects of a strength training protocol with a predominance of the eccentric component on blood count, blood chemistry, and quadriceps muscle ultrasound in university students. 31 students (22.3 ± 4.14 years) of the professional programme in Sports of the Politécnico Colombiano Jaime Isaza Cadavid participated. A mesocycle was developed with three weekly sessions of eccentric training focused on the lower body and core zone. Pre and post-intervention measurements were taken anthropometry, haemogram, lipid profile, ultrasound of the right quadriceps, Bosco test, and Rockport test. The Wilcoxon signed-rank test was used, and the effect size was calculated using rank correlation. Statistically significant changes were observed in haematocrit, mean corpuscular volume, HDL, muscle thickness and echo-intensity, vertical jump power, and maximal oxygen consumption. A four-week eccentric strength training programme generates improvements in haematology, lipid profile, muscle quality assessed by ultrasound, and functional performance in university students. Full article

Fine-grained sedimentary rocks are ideal carriers for astronomical cycle analysis as they can record and preserve significant astronomical cycle signals. Spectral analysis using the Multi-taper Method (MTM) and Evolutionary Harmonic Analysis (EHA) using the Fast Fourier Transform (FFT) were conducted on natural gamma data from key wells in the Es₃l sub-member in the Bonan Sag, Bohai Bay Basin, China. Gaussian bandpass filtering was applied using a short eccentricity cycle of 100 ka, and a “floating” astronomical time scale for the Es₃l sub-member (Lower 3rd sub-member of Shahejie Formation in Eocene) was established using magnetic stratigraphic ages as boundaries. Stratigraphic divisions were made for single wells in the Es₃l of the Bonan Sag, and a stratigraphic framework was established based on correlations between key wells. The research results indicate the following: Firstly, the Es₃l of the Bonan Sag records significant astronomical cycle signals, with an optimal sedimentation rate of 8.39 cm/ka identified. Secondly, the cyclical thicknesses corresponding to long eccentricity, short eccentricity, obliquity, and precession cycles are 38.9 m, 9.7 m, 4.6–3.4 m, and 1.96–1.66 m, respectively. Thirdly, the Es₃l sub-member stably records 6 long eccentricity cycles and 26 short eccentricity cycles, and the short eccentricity curve is used as a basis for stratigraphic division for high-precision stratigraphic correlations. Fourthly, the quality of sandstone-interbedded mudrock is jointly controlled by the short eccentricity and precession. Eccentricity maximum values result in thicker sandstone interlayers, while minimum precession values promote the thickness of sandstone interlayers. Through astronomical cycle analysis, the depositional evolution mechanism of sandstone-interbedded mudrock is revealed. Combined with the results of high-precision stratigraphic division, this can provide a basis for fine evaluation and “sweet spot” prediction of lacustrine shale oil reservoirs. Full article

Achilles mid-portion tendinopathy is defined as a painful thickening of the tendon, identified also on different imagistic examinations, occurring in sport people as well in inactively middle-aged individuals. The chronic and/or relapsing evolution interfere with daily living and alter the quality of life. Eccentric physical exercise is a cornerstone in her management and several injectable agents are used in clinical settings to reduce pain and improve function. According to the presumed pathogenic mechanisms, many classes of agents are in use: corticosteroids, protease inhibitors, sclerosing agents, pro-inflammatory agents, autologous products. The modalities of administration, either intra- or peritendon, the timing and number of sessions are displayed. Practical approach of chronic mid-portion Achilles tendinopathy consists of rest, tendon protection, eccentric exercise and therapeutical injections. The clinicians must choose between a spectrum of agents active on different pathogenic mechanisms, with benefits in the short and medium term. Future research may be focused on comparison between the different agents and on long term evolution. Full article

A series of fault depressions developed in the Kailu area on the southwestern margin of the Songliao Basin, where thick lacustrine fine-grained sedimentary rocks were widely deposited during the initial faulting stage in the Early Cretaceous. These formations serve as the primary source rocks within the depressions. To investigate the depositional cyclicity framework, paleoenvironmental conditions, and source rock development patterns of fine-grained sedimentary strata, this study focuses on the Naiman Sag, selecting Well Nai-10 for wavelet transform and spectral analysis based on natural gamma ray logs. Combining core, well logging, and geochemical element analyses, Milankovitch cycles within the Yixian Formation were identified. The relationship between theoretical orbital periods and sedimentary cycles in a single well was established, enabling the high-precision identification and classification of fine-grained sedimentary cycles. Furthermore, the study explores the sedimentary response to orbital forcing and the development patterns of source rocks. The results indicate that fine-grained sedimentary strata exhibit distinct Milankovitch cyclicity, with a strong correlation between astronomical periods and sedimentary cycles. Using the 100 kyr short eccentricity cycle as the tuning curve, an astronomical timescale and high-frequency cyclic division for the target interval were established. Under the control of long eccentricity cycles, sedimentation exhibits strong response characteristics: near the peak of short eccentricity cycles, the climate was warm and humid, redox conditions were strong, and precipitation was high, facilitating organic matter accumulation. Based on this response relationship, two ideal enrichment models of mudstone and shale under different paleoclimatic conditions are proposed, providing valuable insights for identifying high-quality source rocks and unconventional hydrocarbons in hydrocarbon exploration. Full article

The thick cloud layer enshrouding Venus influences its thermal balance and climate evolution. However, our knowledge of total optical depth, spatial and temporal variations in the clouds is limited. We present the first complete study of the SPICAV IR spectrometer observations in the 1.28- and 1.31-µm atmospheric transparency windows during the Venus Express mission in 2006–2014. The nadir spectra were analyzed with one-dimensional multiple scattering radiative transfer model to obtain the variability of total cloud opacity on the Venus night side. The optical depth recomputed to 1 µm averages 36.7 with a standard deviation of 6.1. Cloud opacity depends on latitude, with a minimum at 50–55° N. In the Southern Hemisphere, this latitude dependence is less pronounced due to the reduced spatial resolution of the experiment, determined by the eccentricity of the spacecraft’s orbit. Cloud opacity exhibits strong variability at short time scales, mostly in the range of 25–50. The variability is more pronounced in the equatorial region. The lack of imaging capability limits the quantitative characterization of the periodicity. No persistent longitude or local time trends were detected. Full article

By integrating a very short shear link–shear slotted bolted connection (VSSL-SSBC) and two self-centering SMA braces (SCBs), a novel self-centering shear link (SC-SL) was developed for installation between a steel brace and steel beam in an eccentrically braced frame (EBF). The SC-SL can enhance the seismic performance and seismic resilience capacity of the EBF by achieving a high bearing capacity and low residual deformation. The mechanical properties of the VSSL-SSBC and SC-SL were designed and analyzed using both experimental and numerical methods. Subsequently, the seismic performances of EBFs equipped with VSSL-SSBC and SC-SL were analyzed under different earthquakes. Validated numerical methods were employed to investigate the deformation modes, stress nephograms, and hysteresis curves of the EBFs. The deformation mode and hysteresis curve of the VSSL-SSBC exhibit an initial frictional slip of the SSBC, followed by the load-bearing response of the VSSL. The skeleton curve of the VSSL-SSBC consists of elastic, slip, elastoplastic, and plastic stages, and the deformation and damage are significantly reduced at the same displacement. In the SC-SL, the SCB undergoes substantial deformation when the SMA is in tension, effectively minimizing residual deformation. Under frequent earthquakes, the stress and displacement of all components in both the EBF-VSSL-SSBC and EBF-SC-SL are essentially equivalent, and the VSSL-SSBC remains elastic, without significant yielding deformation. Under rare earthquakes, incorporating SCB in EBF-SC-SL significantly enhances the ultimate load capacity by 19.66% and reduces the residual deformation by 27.90%. This improvement greatly contributes to the seismic resilience of the EBF. Full article

In this paper, a fault diagnosis method for permanent magnet synchronous motors is proposed, combining wavelet packet transform (WPT) energy feature extraction and a genetic algorithm (GA)-optimized back propagation (BP) neural network. Firstly, for the common types of motor faults (turn-to-turn short-circuit, phase-to-phase short-circuit, loss of magnetism, inverter open-circuit, rotor eccentricity), a corresponding motor fault model is established. The stator current signals during motor operation are analyzed using wavelet packet transform, and energy features are extracted from them as feature vectors for fault diagnosis. Then, a BP neural network is constructed, and a genetic algorithm is used to optimize its initial weights and thresholds, thereby improving the network’s classification accuracy. The results show that the GA-BP model outperforms the SSA-PNN diagnostic model in terms of fault classification accuracy. In particular, for the diagnosis of normal operation, inverter open-circuit, and demagnetization faults, the accuracy rate reaches 100%. This method demonstrates high diagnostic accuracy and practical application value. Full article

Since permanent magnets and rotors are core components of electric vehicle drive motors, accurate diagnosis of demagnetization and eccentricity faults is crucial for ensuring the safe operation of electric vehicles. Currently, intelligent diagnostic methods based on three-phase current signals have been widely adopted due to their advantages of easy acquisition, low cost, and non-invasiveness. However, in practical applications, the fault characteristics in current signals are relatively weak, leading to diagnostic performance that falls short of expected standards. To address this issue and improve diagnostic accuracy, this paper proposes a novel diagnostic method. First, branch current is utilized as the data source for diagnosis to enhance the fault characteristics of the diagnostic signal. Next, a dual-modal feature extraction module is constructed, employing Variational Mode Decomposition (VMD) and Fast Fourier Transform (FFT) to concatenate the input branch current along the feature dimension in both the time and frequency domains, achieving nonlinear coupling of time–frequency features. Finally, to further improve diagnostic accuracy, a cascaded convolutional neural network based on dilated convolutional layers and multi-scale convolutional layers is designed as the diagnostic model. Experimental results show that the method proposed in this paper achieves a diagnostic accuracy of 98.6%, with a misjudgment rate of only about 2% and no overlapping feature results. Compared with existing methods, the method proposed in this paper can extract higher-quality fault features, has better diagnostic accuracy, a lower misjudgment rate, and more excellent feature separation ability, demonstrating great potential in intelligent fault diagnosis and maintenance of electric vehicles. Full article

This paper focuses on the latest advancements in diagnosing faults in Permanent Magnet Synchronous Machines (PMSMs), with particular attention paid to demagnetization, inter-turn short circuits (ITSCs), and eccentricity faults. As PMSMs play an important role in electric vehicles, renewable energy systems and aerospace applications, ensuring their reliability is more important than ever. This work examines widely applied methods like Motor Current Signature Analysis (MCSA) and flux monitoring, alongside more recent approaches such as time-frequency analysis, observer-based techniques and machine learning strategies. These methods are discussed in terms of strengths/weaknesses, challenges and suitability for different operating conditions. The review also highlights the importance of experimental validations to connect theoretical research with real-world applications. By exploring potential synergies between these diagnostic methods, the paper outlines ways to improve fault detection accuracy and machine reliability. It concludes by identifying future research directions, such as developing real-time diagnostics, enhancing predictive maintenance and refining sensor and computational technologies, aiming to make PMSMs more robust and fault-tolerant in demanding environments. In addition, the discussion highlights how partial demagnetization or ITSC faults may propagate if not diagnosed promptly, necessitating scalable and efficient multi-physics approaches. Finally, emphasis is placed on bridging theoretical advancements with industrial-scale implementations to ensure seamless integration into existing machine drive systems. Full article

Background/Objectives: The aim of the present study was to assess the effectiveness of flexibility or strengthening exercises to improve flexibility, strength, muscle architecture, and functional performance in older adults with leg tightness and/or suspected sarcopenia. Methods: Ninety adults with leg tightness and/or suspected sarcopenia (age: 66.8 ± 4.9 years) were randomly allocated to two subtypes of intervention at home: resistance-band exercise (RE) or eccentric exercise (ECC) for those with weakness; static or dynamic stretching for those with tightness; and static stretching plus ECC or no exercise for those with both muscle tightness and weakness. The program consisted of 3–6 weekly sessions over eight weeks. Blinded outcome assessments before and after the eight-week program and at the three-month follow-up included mobility performance via Timed Up-and-Go (TUG), and flexibility and strength tests, as well as measurement of stiffness. Results: All groups had increased peak torque after eight weeks and improved TUG at the three-month follow-up (p < 0.05). Improved plantar flexor strength persisted at the three-month follow-up (p = 0.009). In addition, the RE and ECC groups had increased muscle thickness by 4.0 and 8.7% after eight weeks (p < 0.05). Hamstring flexibility increased in all exercise groups, except the RE group. Moreover, all six groups showed improved calf flexibility, whereas no changes in stiffness were noted. Conclusions: Increases in mobility performance, strength, and flexibility appeared due to learning effects and increased physical activity, rather than the specific training impact. However, strength-based programs may be recommended for older adults with suspected sarcopenia, as they provide additional benefits, such as short-lasting muscle hypertrophy. Full article