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Severe weather, especially strong rain-loaded wind, appears in coastal areas frequently. The strong wind driving raindrops worsens the wind effect and aggravates its impact on the intercity railway bridge and running trains. Based on the Euler multiphase model, for evaluating the effect of raindrops in wind and rain environment on running trains, a numerical simulation approach was adopted in this study, and the influence of the crosswind speed and rainfall with varying characteristic parameters on the aerodynamic performances of intercity trains was analysed. The results showed that the airflow around the train drove some raindrops to show a parabolic projectile feature, and the projectile distance increased as the crosswind speed increased, but the projectile distance showed no noticeable change with the rise in the rainfall, because the impact of the crosswind played a dominant role, while the raindrops provided additional effects in the wind and rain environment. Furthermore, in the wind and rain environment, as the crosswind speed increased and compared to that of the 10 m/s conditions, an increase of 354.37 %, 369.60 % and 355.07 % in C S , C L and C M of the whole train was shown in 30 m/s wind speed conditions, respectively, while, as the rainfall increased to 100 mm/h compared to that of the 20 mm/h, an increase of 6.41 % and 6.25 % in C S and C M of the whole train, as well as a decrease of 0.71 % in C L of the whole train was shown, respectively. [ABSTRACT FROM AUTHOR]

The use of daylight in buildings contributes to energy savings while significantly improving visual comfort and well-being. It is therefore very important to be able to quantify illuminance to take advantage of daylight. Although several models have been proposed in recent years to determine global and diffuse illuminance, the same may not be said of direct solar illuminance, which situates this study in an area of noteworthy scientific and technological interest. Two luminous efficacy models for clear sky conditions are proposed and the results of benchmarking with previous models from the literature are presented. Data collected in Burgos (Spain) were analyzed. Specifically, eight previous models for the prediction of direct illuminance were compared with our two new models. The two new models predicted illuminance more accurately than most of the classic models. Specifically, running the models on the training data yielded Root Mean Square Error (RMSE) values of 2.58 % and 2.76 % for the first and the second model, respectively. Likewise, the test data yielded RMSE values of 3.31 % and 3.49 %, and the Mean Bias Error values with the training data were 0.06 % and 0.11 %, respectively. The models achieved high accuracy levels with both the training and the test data sets. [ABSTRACT FROM AUTHOR]

This study focuses on experimental investigation of the dynamic features and propagation law of ground vibrations induced by suspended monorail transportation (SMT), which is rarely reported. First, a comprehensive field measurement of suspended monorail train-induced ground vibrations is performed and the acceleration responses at different measurement positions are obtained. Then, the vertical and lateral vibrational responses are elaborately analysed in the time and frequency domains. The dynamic features and transmission laws of the ground vibrations are revealed, and some interesting phenomena are discovered. Finally, an effective signal post-processing method is adopted to furthest reduce signal truncation errors. The 1/3 octave analysis method is adopted for elaborately evaluating both the ground vibration levels with time and frequency division under different train operating conditions. The research results can provide useful guidance for route selection of SMT and numerical model validation. • Ground vibration measurement is elaborately performed based on a full-scale SMT test line. • Dynamic features and propagation law of ground vibrations induced by the SMT are revealed. • Effects of train running speed and train load on ground vibration are discussed, and some interesting phenomena are also found. • Ground vibration levels are evaluated through two effective post-processing methods. [ABSTRACT FROM AUTHOR]

Noise from rail transit viaducts often has a negative effect on surrounding buildings and nearby residents. To reduce the bridge vibration and radiated noise, floating slab tracks have been widely adopted in rail transit viaducts. To calculate the vibration of coupled track-bridge systems, both time-domain and frequency-domain methods can be applied although their relative performance is not very clear. This study aims to compare the two approaches and then provide some guidelines in choosing the appropriate method for predicting the vibration. The principle and methodology of the two calculation methods are firstly introduced, and the models for the train, floating slab track and bridge are developed using similar parameters. To further improve the efficiency and accuracy of the frequency-domain method, a half period method and a weighted average method are proposed to calculate the average responses of a certain point on the rail, floating slab and bridge to approximate the response during the pass-by. An indirect method is used to estimate the wheel–rail combined roughness from the measured rail acceleration when the train is running on the bridge, and compared with the direct measurement rail roughness. For the vibration of the bridge and floating slab, comparisons are made between results obtained from the time-domain and frequency-domain methods with different train speeds, and between results from experiment and simulation with different roughness. It is found that the wheel–rail contact forces and other structural responses from the two approaches show good consistency in the frequency region above 20 Hz. It is shown that a good approximation of the response during the pass-by can be obtained using the frequency-domain method by adopting the half period average or a simplified weighted average of two wheel position cases. When using the measured roughness and estimated roughness, the simulated vibration of the floating slab and bridge match well with the experimental results, and the indirect method can be used to modify direct measurement roughness in lower frequency regions. In the vibration prediction, the rail vibration or roughness, and other parameters in the vehicle–track–bridge system, should be measured accurately to ensure high reliability. • The train-induced vibration characteristics of floating slab and bridge coupled system are summarized. • A comparison of time-domain and frequency-domain methods in predicting dynamic response of coupled system is developed. • Two simplified frequency-domain methods with different wheel arrangement cases is proposed and verified. • A field test is carried out to validate the numerical prediction. [ABSTRACT FROM AUTHOR]

To prospectively monitor biomechanics, session-rating of perceived exertion (sRPE), and wellness in a cohort of collegiate Division-1 cross-country athletes over the course of a single competitive season. Prospective cohort study. Healthy Division-1 cross-country athletes (9 males, 13 females) were prospectively followed over a single competitive cross-country season. Wearable sensors were used to collect biomechanics twice per week, along with surveys to assess sRPE and wellness. Mixed model linear regressions were used to assess the relationship among biomechanical measures to sRPE, and to wellness z-scores. Stride length, contact time, impact g, pace, weekly mileage, and running a meet in the day prior to the recorded run explained 25.4% of the variance in sRPE scores across the season (R2 = 0.254, p < 0.001). Contact time and braking g helped explain 3.7% of the variance in wellness (R2 = 0.037, F = 5.70, p = 0.01). There were several identified associations between gait biomechanics and sRPE, yet minimal associations with wellness measures. These findings suggest there are movement adaptations associated with perceived running intensity, however biomechanical measures alone do not lend additional insight into wellness measures. • Sensor-derived biomechanics were associated with perceived efforts among collegiate runners. • Biomechanics were not associated with wellness, suggesting these data offer unique information. • This study offers a foundation for future outdoor assessments on runners' response to training. [ABSTRACT FROM AUTHOR]

[Display omitted] • A flexible zwitterionic ionic conductive (F–Zn) hydrogel was designed for the strain sensor and triboelectric nanogenerator (F-TENG). • The open-circuit voltage (V oc) of F-TENG can reach 245.54 V. Moreover, the short-circuit current (I sc) and transfer charge (Q sc) of F-TENG can arrive at 9.16 µA and 81.16 nC. • As the self-powered pressure sensor, two linear sensing regions of F-TENG can be observed, with sensing sensitivities of 5.9 and 2.05 kPa, respectively. • Moreover, the Gauge Factor (GF) of the F-Zn hydrogel pressure sensor can arrive at 0.99, demonstrating a linear sensing effect. Recently, wearable electronic devices based on ionic conductive hydrogel have received much attention. However, the hydrogels currently reported face challenges in terms of fatigue strength and mechanical properties. Hence, we designed a flexible zwitterionic ionic conductive (F–Zn) hydrogel for the strain sensor and triboelectric nanogenerator (F-TENG). According to the results, the open-circuit voltage (V oc) of F-TENG can reach 245.54 V. The short-circuit current (I sc) and transfer charge (Q sc) of F-TENG can arrive at 9.16 µA and 81.16 nC. As the self-powered pressure sensor, two linear sensing regions of F-TENG can be observed, with sensing sensitivities of 5.9 kPa−1 and 2.05 kPa−1, respectively. In the meantime, when the F-Zn hydrogel serves as strain sensor, the Gauge Factor (GF) can arrive at 0.99. It's important to note that F-TENG can complement the static sensing of the F-Zn hydrogel strain sensor by having application value in dynamic motion sensing. Comprehensive monitoring of running movements is achievable by two sensors with different working mechanisms, paving the way for multifunctional running hydrogel sensors. [ABSTRACT FROM AUTHOR]

• Broad Learning System(BLS) is the first time it used in sleep staging. • Our model is proposed by combining the interpretability of manual feature and the high performance of Broad Learning System. • Our model can effectively merge the contextual feature and signal feature, and greatly save the computational cost. • Our model can be deployed on CPUs, expanding its clinical application. Sleep staging is an essential component of sleep medicine. Traditional expert-based staging method is time-consuming and labor intensive, prompting research interest in automatic staging based on artificial intelligence in recent years. Among the existing automatic staging methods, traditional feature-based staging has strong interpretation and clinical acceptance but lack satisfactory accuracy, while deep learning model-based methods exhibit high performance but limited in interpretability and significant high computational cost. In this work, we propose a concise two-layer network based on the improved Broad Learning System (BLS), which demonstrates exceptional performance and extremely low computing cost. The network comprises a pre-training module and a contextual feature enhancement module. During pre-training, manual features and the improved BLS are employed to establish the fundamental model. Subsequently, the model is optimized by integrating the contextual information into the original features, and after running several training epochs, the final result is obtained. By combining the advantages of the improved BLS and the contextual-feature fusion, our model achieves the state-of-the-art performance on multiple datasets, and the traditional machine learning method with our context-feature method also shows significant improvement. Furthermore, the usage of manual features and our concise context-feature fusion method ensure the model interpretability and reduce the computational cost. Specifically, our model contain approximately 1/14 parameters than the best performing deep learning models. [ABSTRACT FROM AUTHOR]

Detecting ship wakes is essential for locating moving vessels at sea. Of the various wake types, Kelvin wakes are particularly intriguing because of the vital information they convey about ships. However, identifying Kelvin wakes is challenging due to their expansive planar distributions and their variable brightness and forms. This paper introduces a deep neural network-based technique specifically tailored for detecting Kelvin wakes in large-scale, high-resolution optical images. After distinguishing between land and water, the entire water region of the image was segmented into overlapping sub-images. GoogLeNet was then employed to differentiate between Kelvin wakes and natural sea surfaces within each sub-image. Regions exhibiting Kelvin wakes were subsequently identified by combining the wake-classified sub-images. Given the limited diversity of available Kelvin wake samples, the training dataset merged true and simulated Kelvin wake images, which acted as positive samples for the deep neural network. The proposed method, when applied to high-resolution optical images, showcased outstanding Kelvin wake detection capabilities, achieving a recall rate of 94.0% and a precision of 70.8%. When detection was limited to the vicinity of ship hulls, the recall, precision, overall accuracy, and specificity achieved remarkable rates of 94.0%, 70.8%, 92.3%, and 94.1% respectively. Furthermore, this research delved into the influence of training samples and input channels on the detection accuracy of wakes. Various DNNs, were utilized for comparison, including AlexNet, VGGNet with 16 layers, GoogLeNet, ResNet with 18 layers, DarkNet with 53 layers, DenseNet with 201 layers. GoogLeNet stood out due to its Inception module, which integrates multi-size convolution kernels, achieving a recall rate of 94.0% and a precision of 70.8%. When detection was limited to the vicinity of ship hulls, the recall, precision, overall accuracy, and specificity achieved remarkable rates of 94.0%, 70.8%, 92.3%, and 94.1% respectively. [Display omitted] •Kelvin wake detection method for large-scale imagery by deep learning was proposed. •The method training and running efficiency was improved with high accuracy. •Simulated Kelvin wakes effectively made up for the lack of diversity wake samples. •Recall, precision, overall accuracy, and specificity were all more than 94.0%. [ABSTRACT FROM AUTHOR]

• a new graph-based delay propagation model considering train running/dwelling/headway-related factors is proposed; • an attention mechanism for discerning the strengths of influences of factors is used to explain train delay propagation; • The outcomes of the proposed model can be distinctively interpreted by the influence factors; • the predictive performance of the proposed model is significantly improved because of the self-attention mechanism; Explaining train delay propagation using influence factors (to find the determinants) is essential for transport planning and train operation management. Due to high interpretability to train operations, graph/network models, e.g., Bayesian networks and alternative graphs, are extensively used in the train delay propagation/prediction problem. In these graph/network models, nodes represent train arrival/departure/passage events, whereas arcs describe train headway/running/dwelling processes. However, previously proposed graph/network models do not have edge weights, making them incapable of apperceiving the diverse influences of factors on train delay propagation/prediction. The train dwelling, running, and headway times vary over time, space, and train services. This potentially makes these factors have diverse strengths on train operations. We innovatively use the Graph Attention Network (GAT) to model the train delay propagation. An attention mechanism is used in the GAT model, allowing the GAT model to have arcs with diverse weights (learned from data). This enables the GAT model to discern the nodes' diverse influences; thus, with the learned importance coefficients, the model can be distinctly explained by the influencing factors. Further, the model's accuracy is expected to be improved, because the GAT model (with the attention mechanism) can pay more attention (represented by the learned weights) to the significant factors/nodes. The proposed GAT model was calibrated on operation data from the Dutch railway network. The results show that: (1) the influence factors contribute diversely to the delay propagation, and the train headway is the determinant of train delay propagation; (2) the accuracy of the proposed GAT model is significantly improved (because of the attention mechanism), compared against other state-of-the-art graph/network models. In a word, the proposed GAT method improves the interpretability of delay propagation and the accuracy of delay prediction. [ABSTRACT FROM AUTHOR]

Railway wheel polygonization is a type of uneven wear of material which worsens the running stability of trains. As a significant factor influencing the wear, wheel-rail hardness matching (i.e., the hardness ratio H W / H R) might affect the formation of a polygonal wheel. Thus, rolling-sliding wear tests were conducted using three wheel steels matching two rail steels to explore the influence of H W / H R (ranging from 0.649 to 1.263) on the initiation and evolution of wheel polygonal wear. The results show that when matching the softer rail, the wheel was less likely to become polygonal with an increase in H W / H R. When matching the harder rail, the wheel presented earlier polygon initiation under a moderate H W / H R of 0.792. The largest H W / H R of 1.263 presented the best anti-polygon condition for wheel material. The wear mechanism of polygonal wheel was dominated by abrasive, fatigue and oxidative wear at the crest and fatigue wear at the trough. • Evolution of wheel polygon wear is analyzed via rolling-sliding test with high-speed camera and vibration sensor. • Effect of wheel-rail hardness ratio on wheel polygon wear is explored. • Wheel polygon wear is easier to form with wheel hardness decreasing and rail hardness increasing. • Wear mechanism at crest is different with that at trough. [ABSTRACT FROM AUTHOR]

The aim of this study is to investigate the impact of running exercise training protocols (ETPs) with varying intensities on inflammatory responses, with a specific focus on the interactions between inflammatory mediators, cytokines, and Leydig cell steroidogenic activity, as well as testosterone secretion. To this end, 24 Wistar rats were subdivided into sedentary control, low (LICT), moderate (MICT), and high (HICT) intensity continuous running ETP groups. After 8 weeks, the expression levels of Toll-like receptor-4 (TLR-4), nuclear factor-kappa-B (NF-KB), interleukin-6 (IL-6), interleukin-10 (IL-10), Tumor necrosis factor alpha (TNF-α), cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), and the testicular nitric oxide (NO) content were assessed and compared between groups. Moreover, the mean distributions of Leydig cells/mm2 of interstitial connective tissue, their steroidogenic activity, and serum level of testosterone were assessed. The LICT did not show any significant (p > 0.05) change in the expression levels of all aforementioned biomarkers. In contrast, both the MICT and HICT groups demonstrated a significant (p < 0.05) increase in the expression levels of TLR-4, NFK-B, IL-6, TNF-α, iNOS, and COX-2 at both the mRNA and protein levels. The testicular NO has increased in HICT and MICT groups. Despite a decrease in the distribution of Leydig cells in both the MICT and HICT groups, the HICT group exhibited a significant (p < 0.05) reduction in Leydig cell steroidogenic activity and serum testosterone levels. In conclusion, our findings revealed that ETPs can influence Leydig cell steroidogenic activity and testosterone secretion, contingent on their intensity. These effects are attributed to alterations in the expression levels of pro-inflammatory mediators and cytokines. • MICT and HICT led to a significant increase in testicular TLR-4 and NFK-B expression at the mRNA level. • MICT and HICT resulted in an upregulation of testicular IL-6, IL-10, and TNF-α expression. • LICT, MICT, and HICT significantly increased the testicular mRNA level of TNF-α. • MICT and HICT groups displayed a remarkable increase in testicular NO level. • MICT and HICT groups exhibited a remarkable increase in testicular NO level. • MICT and HICT increased TLR-4 expression. • MICT group exhibited compensatory steroidogenic activity • HICT reduced the proportion of Leydig cells with positive steroidogenic activity. • HICT decreased serum testosterone level. [ABSTRACT FROM AUTHOR]

• Propose a DANRT system to improve passenger travel efficiency. • Propose a mathematical model for the carriage scheduling problem in DANRT. • Propose a linearization and segmentation method to facilitate model solving. • Numerical experiments on a Beijing metro line show the effectiveness of DANRT. • Present several observations and operational characteristics of DANRT. This study proposes a dynamic autonomous non-stop rail transit (DANRT) system to improve the travel efficiency of passengers in urban rail transit (URT) systems and solves a pertinent carriage scheduling problem derived from the DANRT system using a mathematical programming model. In the DANRT system, passengers traveling to the same destination are allocated to the same carriage(s), and each carriage can be attached to and detached from trains using the modular autonomous vehicle (MAV) technology effortlessly, which enables all trains to run non-stop throughout the focused operation period. We offer a cost-effective design for the DANRT system. To ensure safe and efficient operations, a mathematical model is proposed for the carriage scheduling problem in the DANRT system, where the number and destinations of carriages required by each station are determined. A linearization and segmentation method for the model is proposed. To examine the effectiveness of the DANRT system, we compare the travel efficiency of passengers in the DANRT system with that in the traditional system by using the origin-destination distribution of passengers on the Batong Line of Beijing Subway. The results demonstrate that passengers in DANRT can save about 2.9 % to 8.6 % of travel time compared with the traditional system. Finally, we conclude several observations and operational characteristics of the DANRT system by numerical experiments. [ABSTRACT FROM AUTHOR]

• 2D-LC separation of oligonucleotides using IPRP separations in both dimensions. • Elution conditions are systematically discovered through iterative retention modeling. • 2D-LC separations provide both the selectivity and sensitivity needed for impurity profiling. • Application to therapeutic siRNA single strands from solid phase oligonucleotide synthesis. Oligonucleotides constitute an emerging and highly complex bioanalytical challenge and it is becoming increasingly clear that 1D methodologies are unable to fully resolve all possible impurities present in these samples. 2D-LC therefore constitutes a perfect solution wherein critical pairs can be sampled from a steep gradient 1D and separated in a shallower 2D gradient. Herein, we provide a facile 2D-LC method development approach to quickly generate high selectivity gradients utilizing ion pairing reverse phase (IPRP-IPRP). In particular we demonstrate how to iteratively generate a 12 % gradient from two training runs and then to utilize that data to predict retentions of analytes with a 2 % gradient with retention prediction errors as low as 3 and 11 %, respectively. This iterative method development workflow was applied to impurity profiling down to 1:1000 for the full-length product and phosphorothioate modified impurities. Additionally, we demonstrated the elucidation of critical pairs in complex crude pharmaceutical oligonucleotide samples by applying tailored high selectivity gradients in the second dimension. It was found that the iterative retention modeling approach allows fast and facile 2D-LC method development for complex oligonucleotide separations. [ABSTRACT FROM AUTHOR]

The imbalanced dataset in actual engineering negatively affects the precision of fault diagnosis because of the severe lack of collected fault data. To effectively address this issue, an adaptive feature fusion assisted generation adversarial network is proposed, which can use very restricted numbers of samples for data augmentation. Firstly, the U-Net network is introduced into the generate adversarial network, which can ensure the spatial characteristics of samples and accurately extract characteristics from extremely finite samples. Secondly, to avoid the problem of reducing the diversity of generated samples due to single signal input, a module for adaptive feature fusion is constructed to guide the generator to learn and effectively improve the diversity of generated samples. Finally, construct a new loss function by utilizing a dual discriminator network to keep the training process running smoothly. To validate the proposed method, experiments are conducted on the datasets from Case Western Reserve University (CWRU) and a self-built test bench. The outcomes demonstrate that the proposed method can generate high-quality samples using very restricted samples, outperforming the comparison methods in terms of structural similarity (SSIM), maximum mean discrepancy (MMD), and Fréchet inception distance (FID) metrics. This shows the advantages of the proposed generation model in terms of sample diversity and similarity and can be used to greatly boost fault identification precision. [ABSTRACT FROM AUTHOR]

• Shaking table tests of the train running on a high-speed railway bridge are carried out based on a four-array shaking table and a 1:10 train-track-bridge model. • Numerical simulation research is carried out, and the test results verify the accuracy of the numerical modeling method. • Near-fault vertical seismic effects on the running safety of trains on bridges are revealed by analyzing the test and numerical data. • From the perspective of mechanism, near-fault vertical seismic effects on the train derailment are investigated by analyzing the wheel-rail relative displacements of the test and the derailment evaluation indexes of the numerical simulation. The vertical component of near-fault earthquake motion is significant and may result in the derailment of trains that are running on bridges. In this study, a shaking table test of a train running on a high-speed railway bridge is performed based on a four-array shaking table and a 1:10 scale model of the train-track-bridge, and the corresponding numerical model is established. The reliability of the numerical model is first verified by test results. Then, with safety and comfort indexes as evaluation criteria, the test and numerical data are analyzed to reveal the near-fault vertical seismic effects on the running safety of trains on bridges. Finally, with the wheel-rail relative displacement of the test and derailment evaluation indexes of the numerical simulation, the near-fault vertical seismic effects on the derailment of trains running on bridges are analyzed to explore the derailment mechanism. The results show that near-fault vertical seismic excitation generally has a negative impact on the running safety of trains on bridges, with a maximum impact of 27% under selected seismic excitations. Furthermore, the negative impact increases with the vertical-to-horizontal peak acceleration ratio. The safety threshold of peak ground acceleration is often reduced due to vertical seismic effects, and the maximum reduction reaches 14.3% under Northridge-01 seismic excitation. In the case of a given lateral seismic excitation, vertical seismic excitation increases the maximum distance that the wheel-rail contact point moves laterally towards the wheel flange and further promotes flange climb derailment. Moreover, vertical seismic excitation reduces the minimum value of the wheel-rail vertical force and increases the possibility of jumping derailment. [ABSTRACT FROM AUTHOR]

In this study, a three-dimensional numerical model was used to analyze the transient pressure on a segment structure and the CFD caused to it under pneumatic loading action. The results of two trains meeting in the tunnel show that the tunnel cross-sectional area, train speed, and tunnel location significantly influence the peak pressure wave generated on the segment structure. After the trains completely exit the shield tunnel, the peak values of the aerodynamic load may still be higher than that of the aerodynamic pressure wave caused by the trains running in the tunnel, and may last for approximately 10 cycles. Based on the characteristics of the pressure peak values, the mathematical relationship between the attenuation rate of the peak-to-peak pressure values and the number of periods was fitted; the CFD equation was modified, and the rationality was verified. The CFD of the segment structure was approximately proportional to the square of the number of aerodynamic load periods. Thus, the maximum CFD calculated for 100 years is 0.107 × 10−2. This indicates that fatigue damage does not occur in the segment structure under an aerodynamic load. • A detailed analysis of the pressure wave peak variations on the segment structure under different working conditions. • A nonlinear correction to the linear cumulative damage equation when considering the interaction of the aerodynamic load. • Validation of the expression between the decay rate of pressure and the number of cycles based on a modified CFD equation. • The maximum cumulative fatigue damage of the 100-year segment structure was revealed to be 0.107 × 10−2. [ABSTRACT FROM AUTHOR]

• A drive-by approach is used to detect scour of a railway bridge. • Continuous Wavelet Transform is applied to simulated train acceleration signals. • Scour detected by subtraction of CWT coefficients for healthy and scoured cases. • A 'blind' test is carried out with an external collaborator to verify the approach. This paper numerically investigates the feasibility of using bogie acceleration measurements from a passing train to detect the presence of bridge scour. The Continuous Wavelet Transform is used to process the simulated acceleration measurements for a number of train passages over a scoured bridge, with scour represented as a local reduction in stiffness at a given pier. Average Wavelet coefficients are calculated for a batch of train runs passing over the same bridge. A scour indicator is developed as the difference in average coefficients between batches from the healthy bridge and when the bridge is damaged by scour. The method is assessed using a blind test, whereby one author simulated trains passing over a bridge in various states of health. The remaining authors were provided only with the train accelerations and had to predict the state of scour without any prior knowledge. This scour indicator performed quite well in the blind test for normal vehicle operating conditions. [ABSTRACT FROM AUTHOR]

Super high-speed evacuated tube transport is an important development direction of green, energy-saving, and low-drag rail transit in the future. A great deal of aerodynamic heat and pressure change are produced by a tube train running in a closed and long tube with a big blocking ratio at high speed, and the shock wave generated by the train running at supersonic speed further aggravates the aerodynamic phenomenon in the tube, resulting in a large increase of temperature and abrupt pressure change in the tube, endangering the structural safety of the vehicle body and affecting the normal operation of equipment in the vehicle and tube. The purpose of this paper is to find new aerodynamic phenomena, study the formation and evolution mechanism of aerodynamic heating in the tube and influence of the Mach number at subsonic, transonic, and supersonic speed. The results show that shock waves appear in the front and rear of the tube train, the shock reflection is confined to the expansion wave at the tail of the tube train, and the flow field around the tube train, pressure, temperature, and so on in the tube are significantly changed by the shock wave. • Aerodynamic characteristics of tube train are simulated by DDES. • A turning point appears in the relationship between C d and Mach number. • An expansion wave appears behind the tube train running at transonic speed. • Shock waves and their reflection are confined to the expansion wave. • Temperature difference between front and rear of the tube train is large. [ABSTRACT FROM AUTHOR]

Aerobic exercise induces neuroprotection, but few studies investigated whether strength training has similar potential. Here we examine whether effects of strength training differ from those of running training concerning cognitive symptomatology, oxidative stress and cholinergic status in a model of AD-like cognitive impairment induced by intrahippocampal infusion of a mix of β-amyloid peptides (Aβ) in rats. Male Wistar rats were submitted to 8 weeks of running exercise (RunEx; 40 min sessions at 70% of indirect VO 2 max, 3 times/week) or strength exercise (StrEx; 3 sessions/week, 12 repetitions in 8 sets, 2 sets with repetitions at 50%, 2 at 75%, 2 at 90% and 2 at 100% of the maximum load), followed by Aβ infusion in the dorsal hippocampus. Short-term (STM) and long-term (LTM) object recognition (OR) and social recognition (SR) memories were evaluated. Hippocampal oxidative status was determined by quantification of reactive oxygen species, lipid peroxidation by thiobarbituric acid reactive substance test, total antioxidant capacity by ferric reducing/antioxidant power, and acetylcholinesterase enzyme activity (AChE). Aβ infusion impaired STM and LTM and resulted in higher hippocampal oxidative damage and impaired AChE activity. StrEx results in better neuroprotection than RunEx by preventing deficits in OR and SR memories, prevents increases in lipid peroxidation, and decreases in AChE activity. RunEx elicits neuroprotection only for SR memory deficits, prevents increase in ROS and lipid peroxidation, and preserves the total antioxidant capacity. While RunEx effects are related to oxidative status, only StrEx shows potential to also influence the cholinergic system. • Strength and running training impact differently on memory. • Running improves social recognition memory. • Strength training enhances social recognition and object recognition memories. • Only strength training promoted benefits to the cholinergic system. • Strength training can be as neuroprotective as running in an AD-like model. [ABSTRACT FROM AUTHOR]

The dynamic economic situation in the country and the world supports a high demand for training services. Their provision requires more and more advanced IT support. The purpose of this article is standardisation of the assumptions for the design of an IT system intended for managing business processes present within the framework of training implementation undertakings, including those carried out in the e-learning mode. It is assumed that the pre-project, conceptual modelling of business processes and operations necessary for the organization, running and settlement of training, developed by the authors, shall provide the designers with the revised domain knowledge and by this it will increase the quality of the proposed IT system supporting the functioning of a company providing training services. Also, it will increase the economic viability of the training projects managed via such a system. [ABSTRACT FROM AUTHOR]

Unsteady Reynolds-averaged Navier–Stokes (URANS) simulations were performed to simulate the flows around three different train types as they enter a tunnel. The three models—a short train, a double train, and a long train—were used to analyze the influence of the train configuration on the surrounding airflows and aerodynamic performance. The numerical predictions showed good agreement with existing experimental data. The maximum positive velocity peak induced by a short train passing through a tunnel was 140% larger than that produced in open air. The amplitudes of the slipstream velocity components decreased as the height from the ground increased. Large differences were found between the velocity fields produced by long and double trains. The velocity field had a large negative peak when a long train traversed the tunnel. This peak grew along the tunnel towards the exit. When a train is running in a double-track tunnel, the airflow above the two tracks moves in opposite directions. The double train induced a 53% higher velocity than the single train, but only a 6% higher velocity than the long train. • Impact of marshalling length and form on the tunnel slipstream was numerically studied. • The train slipstream in the open air and passing through the tunnel has been compared. • The three-dimensional slipstream velocities induced by a double train passing the tunnel has been analysed. • The mechanisms of the pressures and the slipstream velocities at different locations of the tunnel has obtained. [ABSTRACT FROM AUTHOR]

• Drivers chose whether to go through gaps in traffic in fire-appliance driving clips. • Novice fire-appliance drivers were worse at this task than more experienced drivers. • All drivers looked more at the right edge of the gap than the left... • ...though our safest drivers had the shortest fixations on this location. • This test may provide a future training and assessment tool. Low-speed collisions are a common occurrence for UK Fire and Rescue Services, with frequent bumps and scrapes adding up to create a significant drain on emergency service budgets, and damaging public faith in the service. We hypothesised that the decision to drive through a gap, or aperture, created by other vehicles and/or road furniture, may be related to driver experience and risk-level. To create a test to assess this skill, video clips were recorded from a fire appliance on blue-light training runs. Eighteen clips were selected on the basis that they culminated in a narrow aperture that the film-driver either navigated through, or stopped and waited for other vehicles to move and the gap to widen. Drivers were required to watch these clips, which paused at the point that the film-driver made the decision to either go though, or to wait. The participants rated their belief that the appliance would fit through the gap, and how confident they would be to drive through that aperture themselves (on a 1–8 scale). Novice fire-appliance drivers were less accurate in deciding whether to proceed or not, though their criterion threshold did not differ to that of more experienced drivers. All drivers favoured looking at the right edge of the aperture (either a vehicle or road furniture), but low-risk, experienced fire appliance drivers had the shortest fixations on this area. The results suggest that a video-based test of aperture judgement can differentiate between fire-appliance driver groups based on experience, opening the way for future testing and training tools using this methodology. [ABSTRACT FROM AUTHOR]

A novel recognition method for optical fiber vibration signals is proposed to monitor the running trains real-time and accurately using the phase-sensitive optical-time-domain reflectometer (Ф-OTDR) and the improved Canny. Firstly, all kinds of noise is reduced by the cubical smoothing algorithm with five-point approximation to enhance timefrequency characteristics of vibration signals and shorten the calculation time when compared with the stationary wavelet transform. Then it extracts vibration signals of the running trains by differencing and thresholding. Finally, we introduce the improved Canny edge detection to make the edges clearer. Through on-site test of SHUO HUANG Railway, the error of this method is less than 10m, which can be used as a secondary measure to monitor the running trains. [ABSTRACT FROM AUTHOR]

This paper focuses on the resilience of rail freight operations when affected by extreme weather events. Such events, most likely linked to climate change, are becoming more common and it is vital to mitigate their effects on freight transport activity. Based on a British case study of rail network disruption resulting from a key line closure in early-2016, the analysis considers the impacts on rail freight service provision and the wider supply chains. Following a review of the relevant literature, the case study is analysed using data from a combination of sources including an annual rail freight database, open access real-time train running data, observation surveys and stakeholder interviews. This reveals widespread consequences of the disruption, with fewer freight trains operated than normal, and longer and less punctual journeys for those which ran. However, despite the considerable disruption during the period of the line closure itself, there has been no discernible long-term impact on the rail freight flows which were impacted by the closure. The insight provided by the analysis is used to make a series of recommendations to the rail industry and policy makers. • Analysis of rail freight service disruption resulting from extreme weather event. • Considerable impacts on service provision, journey times and train punctuality. • Many other operational and wider supply chain impacts also acknowledged. • No lasting damage to rail freight flows was identified in this particular case. • Structured set of recommendations to help to reduce impacts of similar events. [ABSTRACT FROM AUTHOR]

Highlights • Propose a framework for simulating maglev trains running over transitional viaducts. • The transitional viaduct is assumed to be realistically deformable, instead of rigid. • Both curve radius and height difference of the inner and outer rails are considered. • The motion of train running over a transitional track is expressed by trajectory coordinates. • Analysis results are verified by the experimental ones for the Shanghai maglev line. • Vehicle rolling motions affect significantly the ride quality on transitional tracks. Abstract This paper presents a general framework for the dynamic analysis of high-speed maglev trains running on elastic transitional viaducts, a complicated problem that lacks an efficient analysis tool. Unlike the straight and circular tracks, both the curve radius (CR) and height difference (HD) between the outer and inner rails vary along the transitional track. To start, the motion of each vehicle of the train running over a transitional track is expressed by a set of trajectory coordinates, with their orientations given in the Euler angles as functions of the CR and HD. The elastic transitional viaduct is simulated by finite elements in the global coordinates. For the maglev trains, the electromagnet force-air gap model is used to account for the interaction and coupling effect between the moving vehicles and supporting viaduct. By applying the proposed framework to the Shanghai maglev line (SML), the dynamic responses of the maglev vehicles running on the transitional viaduct are studied and compared with those on the straight and circular viaducts. Moreover, the effects of transitional track length and cant deficiency on the coupled system are investigated. The results show that for vehicles running on the transitional track, the levitation forces and vehicle's angular velocity are highly related to the rate of change of HD of the track. The length of the transitional viaduct affects significantly all the vehicle's responses. The increase of deficient cant angle causes a sharp increase in the responses of the transitional viaduct in both the radial and rotational directions. [ABSTRACT FROM AUTHOR]

Abstract Safety is the eternal theme of railways, especially the heavy-haul railway, where trains are of great mass, trucks with large axle loads or vehicles with high density and volume. According to the characteristic that the vibration of the environment around the optical fiber will change when the train passes, a new method for monitoring the train running condition of the heavy-haul railway is put forward by using distributed acoustic sensor (DAS) technology. The method can pick up the vibration signal generated by the surrounding environment through optical fiber for real-time monitoring and positioning. Via experiments and testing on site, the fact that the method can acquire the running condition information such as the length, speed, position and direction of trains in real- time and continuously. The positioning error is less than 20m. In addition, the multi-level wavelet decomposition denoising method is used to filter the ambient noise in the original signal. The time domain feature is extracted by calculating the difference between before and after the signal and the effective signal of trains is obtained based on the dynamic threshold. Finally, the author uses the connected component labeling algorithm to identify trains and achieves a good result. [ABSTRACT FROM AUTHOR]

Summary Purpose The relationships between distance (D lim), speed (S) and exhaustion time (t lim) can be described by different empirical models: power laws (D lim = kt lim g, and S = kt lim (g −1) in Kennelly's model); critical speed (S Crit) (D lim = a + S Crit t lim) and logarithmic model (S = 1–E*ln t lim in Péronnet–Thibault model). Methods These models have been applied to the performance of nine physical education students. In the first session, they performed the Montreal Track Test whose speed at the last stage (sMTT) is assumed to correspond to maximal aerobic speed. Thereafter, they performed 3 exhausting running exercises at 90, 100 and 110% sMTT, in different sessions with randomized order. The values of g and k were computed as (g 1 , k 1) from t lim at 90 (t lim90), 100 (t lim100) and 110% sMTT (g 1 , k 1) and also from t lim90 and t lim100 (k 2 , g 2). The values of S Crit were normalized to sMTT. Results Significant correlations (r > 0.999) of the relationships between the logarithms of D lim and t lim were observed. S Crit was not significantly correlated with g 1 , g 2 and E. In contrast, the correlations between the individual values of g 1 , g 2 and E were highly significant. Conclusion The high relationship between the logarithms of D lim and t lim suggested that power laws can be applied to subjects not-specialized in endurance. However, further studies with different protocols are necessary to determine if the power-law model is more accurate and useful than the logarithmic model in subjects who are not specialized in endurance. [ABSTRACT FROM AUTHOR]

Previous studies reached contrary conclusions regarding the train effect on the lateral structural vibration of track-bridge system. Existing shaking table tests failed to address the contrary due to their lack of running train model. In this paper, a shaking table test with a running train model was carried out to verify the train hitting and damping effects, and evaluate the effect degree of train operation on the structural vibration. The results show that the hitting effect on the track structure vibration is considerable but that on the bridge structure vibration is limited; the damping effect on the track and bridge structure vibrations is not significant; under seismic excitation, the irregularity-induced vibration increment of track structure reaches 300%, while that of bridge structure is small; the aseismic design of high-speed railway track-bridge system can be simplified by ignoring the train if the bridge structure response is adopted as the major evaluation index. • The novelty of the research: • A shaking table test with a running train was carried out. • The assumption of train hitting effect was confirmed through the test. • The assumption of train damping effect was rejected through the test. • The effect degree of train operation on the structural vibration was evaluated. [ABSTRACT FROM AUTHOR]

We present a fast method for calculating the effects of ammonia emission reduction scenarios on reduced nitrogen components over the Netherlands. The method combines the EMEP4NL model, which is a full atmospheric chemical transport model (ACTM), with the SHERPA tool, which is an approximate representation of a full ACTM. The SHERPA tool uses a geographically weighted regression method to derive source-receptor relations, based on a limited number of "training" runs of the ACTM (here, EMEP4NL). The training runs consist of a base run of the year of interest plus uniform emission reduction runs for the primary pollutants of interest. Once the source-receptor relations are derived, scenario studies can be performed at a much lower computational cost with SHERPA (i.e. order 104–105 more efficient) as compared to a full run with the EMEP4NL model. Here, we study five specific ammonia emission reduction scenarios, in which a 30% emission reduction is enforced for specific regions in The Netherlands, Germany and Belgium. Our analysis shows that the EMEP4NL model and the SHERPA tool yield similar results in terms of the reduction of the yearly average concentration and deposition of reduced nitrogen components. Because of its computational efficiency and ability to adequately reproduce the results of the EMEP4NL model, the SHERPA tool is relevant for policy making. It can provide predictions of the effects of many different local emission reduction measures in a computationally efficient manner. • We present a method to perform fast ammonia emission reduction studies with a focus on reduced nitrogen components. • An atmospheric chemical transport model is used to train a simplified model. • We validate our results for small, arbitrarily-shaped areas in The Netherlands, Belgium and Germany. • Our method leads to a factor 104 reduction in computation time and adequate accuracy compared to the full model. • It enables policy makers to efficiently study many different local emission reduction scenarios in an efficient manner. [ABSTRACT FROM AUTHOR]

Recommender Systems (RS) play a crucial role in our lives. As users become continuously connected to the internet, they are less tolerant of obsolete recommendations made by an RS. Online RS has to address three requirements: continuous training and recommendation, handling concept drifts, and the ability to scale. Streaming RS proposed in the literature address the first two requirements only. That is because they run the training process on a single machine. To tackle the third challenge, we propose a Splitting and Replication mechanism for distributed streaming RS. Our mechanism is inspired by the shared-nothing architecture that underpins contemporary big data processing systems. We have applied our mechanism to two well-known approaches for online RS, namely, matrix factorization and item-based collaborative filtering. We conducted experiments comparing the performance with the baseline (single machine). Evaluating different data sets, experiments show online recall improvement by 40% with more than 50% less memory consumption. [ABSTRACT FROM AUTHOR]

• The damage state and residual deformation of the bridge-track system after different earthquake intensities are studied. • OpenSees-TRBF co-simulation method is proposed for the running safety analysis considering the post-earthquake damage state of the bridge-track system. • The post-earthquake safety speed thresholds of train are analyzed. A bridge–track system (BTS) is inevitably damaged during an earthquake; this is reflected in its stiffness deterioration and residual deformation, which affect the post-earthquake running safety of trains. The influence of the post-earthquake damage state of an actual BTS on train running safety remains unclear. Hence, this study mainly discussed the influence of post-earthquake bridge–track damage state and residual deformation on running safety and established a safe speed limit for trains under different seismic intensities. A finite element (FE) model of a simply supported railway BTS was established using the OpenSees software. A nonlinear seismic response analysis was performed under different ground motion intensities (0.1, 0.3, and 0.6 g for frequent, design, and rare earthquakes, respectively), and bridge damage, fastener damage, and residual deformation of the rail after the earthquakes were studied. An OpenSees-TRBF (train-rail-bridge-foundation coupled system dynamic analysis software, TRBF) co-simulation method was developed to analyze the running safety of trains after earthquakes under a damaged state of the BTS based on the TCP/IP communication interaction technology. A safe speed limit for trains considering the post-earthquake damage state and residual deformation was proposed, providing a reference for the post-earthquake capacity of trains. The results of the BTS seismic damage analysis showed that the residual displacement of the bearing was the fundamental reason for the change in the rail line shape, and fastener damage mainly occurred in the range of 2–4 fasteners at the end of the girder under the design and rare earthquakes. The results of the running safety analysis showed that, if damage to the BTS is ignored, the running safety after an earthquake will be misjudged. Based on the continuous overrun time limit index, the running safety indices for ground motion intensities of 0–0.4, 0.4–0.5, and 0.5–0.6 g could meet the speed requirements of 350, 300, and 150 km/h, respectively. This study provides some references and suggestions for the running safety of trains following an earthquake. [ABSTRACT FROM AUTHOR]

Summary Objective The purpose of this study was to evaluate the effect of water running training on immune-endocrine parameters evaluated in peripheral blood of overweight-obese women. Methods Eleven sedentary overweight-obese women (age 48.81 ± 12.87 years; body mass index 34.56 ± 4.08 kg/m 2 ) participated of 12-week of aerobic water running training in a heated swimming pool (70 minutes/session; 3×/week). In addition, nine women matched to age and body mass index were recruited to sedentary control group (age 49.9 ± 10.5 years; body mass index 33.05 ± 3.45 kg/m 2 ). Serum levels of interleukin-6 (IL-6), interleukin-10 (IL-10), interleukin-17a (IL-17a), interferon-gamma (INF-γ), tumor necrosis factor-alpha (TNF-α), salivary cortisol, and the peripheral frequency of CD3+CD4+ and CD3+CD8+ T cells were evaluated before and after 12 weeks in exercised individuals and after 12 weeks in control subjects. In addition, anthropometric measurements (body mass, % of body fat and trunk circumferences) and functional capacity (VO 2Peak and time to exhaustion) were also evaluated. Results After 12 weeks of exercise training, serum adiponectin ( P = 0.030), IL-10 ( P = 0.01) and TNF-α ( P = 0.004), and CD8+ T cells frequency ( P = 0.03) increased significantly, while salivary cortisol reduced ( P = 0.003) in exercised women. After 12 weeks of training, exercised individuals had higher TNF-α levels ( P = 0.02), CD4+ ( P = 0.03) and CD8+ ( P = 0.04) T cells than control group. In addition, exercised women reduced the waist circumference ( P = 0.030) and improved the time to exhaustion ( P = 0.003). Conclusion In conclusion, deep water running was able to modulate immune-endocrine parameters in absence of significant improvements in body composition or VO 2Peak in overweight-obesity women. This training could be an interesting tool to control the obesity-related chronic low-grade inflammation. [ABSTRACT FROM AUTHOR]

The air flow underneath high-speed trains have been measured at full-scale for three types of high-speed trains running on two types of ballasted tracks, and the characteristics of the flow have been investigated and comparatively analyzed related to the train and track types. 6 Kiel probe rakes vertically distributed in 40 mm interval from just above the track surface have been employed to measure the temporal histories of wind velocity during the passage of train. The results show that the flow under test trains reached fully-developed state before the end of the second vehicle and maintains until the start of the last vehicle, and average velocities over the fully-developed region show very good consistency for no more than 3 repeated samples. The vertical profile of average velocity over the fully-developed region has been suggested as a useful model to represent the characteristics of the flow underneath high-speed trains, and equivalent roughness of the test trains and tracks have been obtained by introducing the analytical solution of the turbulent Couette flow. The resulting values of equivalent roughness of Korean high-speed trains ranged from 50 mm to 150 mm, and that of the ballast track was 150 mm. • A comprehensive description and analysis have been made for full-scale test campaigns conducted in Korea over the years. • The vertical profile of average velocity has been suggested as a useful model for underfloor flow of high-speed trains. • Equivalent roughness of the test trains and tracks have been obtained by introducing the turbulent Couette flow analogy. • The resulting values of equivalent roughness ranged from 50 mm to 150 mm for trains, and was 150 mm for ballast track. [ABSTRACT FROM AUTHOR]

Virtual coupling (VC) is an advanced technology in train control systems, which enables trains to run information with a small tracking interval. Hence, it can significantly increase the capacity of rail transit. Similar to the vehicle platooning, most established VC approaches select the constant time/spacing gap commonly as the spacing policy but regards the relative braking distance as a constraint. These spacing policy diminish the priority of safety concern in train control systems due to the severity of incidents and economic loss. Motivated by this research gap, in this paper, we designed a stabilized virtual coupling scheme for a train set with heterogeneous braking dynamics capability. Specifically, a relative braking distance based spacing policy is introduced according to the braking dynamics capability of the train, which is a typical characteristic that distinguishes it from the vehicle platoon model. A linear control architecture suitable for the virtual coupled train set (VCTS) is designed to maintain the equilibrium spacing. Sufficient conditions to ensure the local stability are derived and obtained in this paper. The impact of braking dynamics capability on the string stability is analyzed in terms of acceleration and spacing difference respectively in the frequency domain by using the Laplacian transformation. For the former, the necessary and sufficient conditions to ensure the string stability are given, and for the latter, a numerical traversal method to summarize the impact of the heterogeneous braking dynamics capability on string stability is given based the former. Two sets of test examples are given, proving the correctness of the necessary and sufficient conditions of the former and the applicability of the research method of the latter, respectively. • Virtual coupled train set with heterogeneous braking dynamics capability. • Sufficient conditions to ensure the local stability of the controller. • The impact of braking dynamics capability on the string stability. [ABSTRACT FROM AUTHOR]

Summary Objective Training high–living low model has been studied as an intermittent hypoxic training (IHT) for anaerobic performance improvement. To test the hypothesis that a high-intensity circuit strength training (CST) performed in hypoxia increases the anaerobic running performance at sea level. Equipment and methods Twelve sub-elite male 400-m runners were divided into two groups: hypoxia (HYP) ( n = 6) and control (NOR) ( n = 6). Twelve sessions were performed over a period of four weeks (three days/week) without any additional running training. Hypobaric training was performed at a simulated altitude of 3000 m (700 hPa; 10.15 PSI). The anaerobic running performance was tested with a repeated interval running training (RIR). Based on an “all-out” 300-m test performed before and after CST, the subjects performed as many sets as they could at 90% of the individual maximal speed reached with a three-minute rest period between sets. Results As compared to controls, the HYP group showed the following responses post CST: RIR +20.5% (number of sets) ( P < 0.03); (HYP: 4.3 ± 1 to 6.6 ± 1.9 vs. NOR: 3.6 ± 1 to 4.6 ± 1.3), maximal lactate accumulation (in the last set) +8.1% ( P < 0.03) (HYP: 11.8 ± 1 to 15.7 ± 1.3 vs. NOR: 12.5 ± 0.9 to 14.6 ± 1.6). Maximum and recovery heart rates finishing the test and hematology did not show statistically significant differences ( P > 0.05). However, CST in HYP showed a higher HR avg (152.6 ± 6.2) than sea level training (144.4 ± 5.1) ( P < 0.01). Conclusions These data indicate that a CST in hypoxia conditions increases the anaerobic performance in trained athletes. [ABSTRACT FROM AUTHOR]

Vibration induced by urban rail transit has been a growing public concern worldwide. In this context, medium-low speed maglev trains gradually stand out due to their environmentally-friendly advantages in vibration and noise control. However, few studies have investigated maglev train-induced vibration, and much uncertainty still exists about the environmental vibration caused by underground medium-low speed maglev trains. This paper presents a numerical study of train-induced vibration and proposes a hybrid prediction model based on vehicle-track spatially coupled dynamics in the 2.5D FE framework. This method could consider the nonlinear behaviour of the vehicle-track system in more detail, and the application of Green's function makes this method more efficient when dealing with multiple conditions. Moreover, field measurements are carried out on maglev train-track-embankment system, and measured data show good agreement with the prediction results in the time and frequency domain, verifying the accuracy of the proposed model. Numerical analysis is conducted for the vibration response of the vehicle-track-tunnel-soil system, which reveals the transmission behaviour of the maglev train-induced vibration in layered soils, along with the possible causes of vibration amplification phenomena disclosed. Finally, the vibration levels caused by the maglev and subway trains are compared to quantify their differences. Related results provide insights for unveiling the mechanism of impact brought by daily maglev trains on the neighbouring environment and the quality of residents living alongside. [Display omitted] • Environmental vibration induced by medium-low speed maglev train was conducted. • An efficient prediction model was proposed to calculate underground train-induced vibration. • Field measurements were carried out to verify the reliability of the proposed model. • The vibration differences caused by maglev trains and subway trains were revealed. [ABSTRACT FROM AUTHOR]

The derailment of any wheel of a running train results in failure of the safe operation of the train. Therefore, the running risk of each wheel must be comprehensively considered when calculating the running safety and reliability of a train. In this study, a methodology for calculating the global reliability of the running safety of a train on a bridge under crosswinds is proposed using the probability density evolution method (PDEM)-based equivalent extreme value principle. First, a refined 3-D train-track-bridge interaction model is constructed to accurately obtain the dynamic response of a train on a bridge under crosswinds. Second, a dimension-reduced scheme is developed to simulate the representative samples of turbulent winds and track irregularities so that the stochastic processes can be expressed using only two random variables. Third, the PDEM-based equivalent extreme value principle is proposed to efficiently calculate the global reliability of the running safety of trains, where four running safety indexes, namely the derailment coefficient, wheel unloading rate, and wheel-rail vertical and lateral relative displacements, are used to evaluate the running safety of the train. Using numerical examples, the accuracy of the proposed methodology is verified through comparison with the field measurement data and Monte Carlo method, and the influence of the number of representative points on the accuracy is investigated. Furthermore, the differences between the global reliability and single-wheel reliability as well as those between the time-dependent and time-independent reliabilities of running safety are discussed in detail. • A method for calculating the global reliability of the running safety of a train on a bridge under crosswinds is proposed. • A dimension-reduced scheme to simulate the representative samples of turbulent winds and track irregularities is developed. • Differences between the global reliability and single-wheel reliability of running safety are discussed. • Differences between the time-dependent and time-independent reliabilities of running safety are also discussed. [ABSTRACT FROM AUTHOR]

The light-weight and high-speed of modern high-speed trains make the safety and comfort of trains running on bridges prominent in windy environments. The installation of wind barriers can significantly improve the running performance of high-speed trains by reducing the action of wind on the train body. By using the developed moving model test rig in wind tunnel, this paper analyzed the dynamic interaction of wind barrier on the aerodynamic characteristics of the moving train. The windproof performance of wind barrier with different air porosity is detailed discussed. Influences of train speed, wind velocity and lane position on train's aerodynamic coefficients are quantified according to the test results. The result reveals the difference of train's aerodynamic coefficients between static and moving model tests and found static model test may overestimate the reduction rates of wind barrier on train's aerodynamic coefficients. The decreased train speed and increased wind velocity increase the change values of side and overturning coefficients caused by the wind barrier, while decrease the change of lift coefficient. The wind barrier introduces the opposite law of changes in trains' aerodynamic coefficients with it running at the different lanes, leading to different windproof effect of wind barrier on train's aerodynamic characteristics. • Windproof performance of wind barrier on moving train's aerodynamic characteristics is conducted on a bridge. • Necessity of using moving model to study train's aerodynamic parameters is highlighted. • Performance of wind barrier is obvious affected by the air porosity, yaw angle and lane position. [ABSTRACT FROM AUTHOR]

This paper explores the effect of goal-oriented external perturbations created by elastic tubes attached to the hip and ankles on lower limb joint variability and hip-knee and knee-ankle coordination variability during running. Kinematics of ten healthy male runners were analysed prior to and following a 7-week tube running intervention while running with and one without this constraint. The training intervention was based on variable training aspects to increase within-movement variability and adaptability of the running pattern. To analyse the effects of the tubes on the running pattern, the phase plot vector length deviation (i.e., the standard deviation of the phase plot vector length) for the within-joint variability and the continuous relative phase variability for the joint coupling variability were calculated. Results revealed acute increases of variability in both parameters. However, after the intervention, variability of the tube running situation returned to normal for all couplings and joints except the knee. No transfer effects to normal running were observed. This suggests very rapid adaptations to such perturbations. In the long-term, it may ask for more or different variations. [ABSTRACT FROM AUTHOR]

Accelerometers are increasingly used tools for gait analysis, but there remains a lack of research on their application to running and their ability to classify running patterns. The purpose of this study was to conduct an exploratory examination into the capability of a tri-axial accelerometer to classify runners of different training backgrounds and experience levels, according to their 3-dimensional (3D) acceler-ometer data patterns. Training background was examined with 14 competitive soccer players and 12 experienced marathon runners, and experience level was examined with 16 first-time and the same 12 experienced marathon runners. Discrete variables were extracted from 3D accelerations during a short run using root mean square, wavelet transformation, and autocorrelation procedures. A principal component analysis (PCA) was conducted on all variables, including gait speed to account for covariance. Eight PCs were retained, explaining 88% of the variance in the data. A stepwise discriminant analysis of PCs was used to determine the binary classification accuracy for training background and experience level, with and without the PC of Speed. With Speed, the accelerometer correctly classified 96% of runners for both training background and experience level. Without Speed, the accelerometer correctly classified 85% of runners based on training background, but only 68% based on experience level. These findings suggest that the accelerometer is effective in classifying athletes of different training back-grounds, but is less effective for classifying runners of different experience levels where gait speed is the primary discriminator. [ABSTRACT FROM AUTHOR]

High-speed railway lines are widely distributed worldwide. The surrounding wind environment of such railway lines is complex, which significantly affects the safety of high-speed train operations. Using a combination of the computational fluid dynamics method of improved delayed detached eddy simulation and sliding grid technology, the effects of one- and two-side windbreak walls on the unsteady aerodynamic performance of a high-speed train running under a crosswind on a double-track railway line with an embankment and the flow-field characteristics around the train were systematically studied. The grid independence and numerical methods used in this study were verified. The results showed that when the windbreak wall was absent, the aerodynamic performance of the train running on the upstream railway line was the poorest, while the train running on the downstream railway line exhibited large aerodynamic fluctuations. The windbreak wall significantly reduced the aerodynamic force and its fluctuation; the one- and two-side windbreak walls had different effects on the unsteady aerodynamic performance of trains running on the upstream and downstream railway lines under a crosswind. The one-side windbreak wall could restrain the aerodynamic fluctuation of the train more and is thus preferred from the perspective of construction effort and cost. • Effects of one- and two-side windbreak walls on the unsteady aerodynamic performance of a moving train under a crosswind were studied. • Aerodynamic performance of the train running on the upstream railway line was the poorest. • One-side windbreak wall restrain the aerodynamic fluctuation more and is preferred from the perspective of effect and cost. [ABSTRACT FROM AUTHOR]

• HRV-guided training allows profesional runners to achieve higher training intensities. • This is reflected in their cardiovascular performance and HRV enhancement. • The increment in HRV scores suggest better cardiovascular adaptations. • A polarized training is recommended to improve performance and vagal modulation. Purpose: To analyze the training structure following a heart rate variability (HRV) -guided training or traditional training protocol, determining their effects on the cardiovascular performance of professional endurance runners, and describing the vagal modulation interaction. Methods: This was an 8-week cluster-randomized controlled trial. Twelve professional endurance runners were randomly assigned to an HRV-guided training group (HRV-G; n = 6) or a traditional training group (TRAD-G; n = 6). The training methodology followed by the HRV-G was determined by their daily HRV scores. Training intensities were recorded daily. HRV4Training was used to register the rMSSD every morning and during a 60-second period. Cardiovascular outcomes were obtained through an incremental treadmill test. The primary outcome was the maximal oxygen uptake (VO 2max). Results: Total training volume was significantly higher in TRAD-G, but moderate intensity training was significantly higher in HRV-G (X ± SD Dif =1.98 ± 0.1%; P = 0.006; d = 1.22) and low intensity training in TRAD-G (X ± SD Dif =2.03 ± 0.74%; P = 0.004; d = 1.36). The maximal velocity increased significantly in HRV-G (P = 0.027, d = 0.66), while the respiratory exchange ratio increased in TRAD-G (P = 0.017, d = 1). There was a small effect on the LnRMSSD increment (P = 0.365, d = 0.4) in HRV-G. There were statistical inter-group differences in the ∆maximal heart rate when ∆LnrMSSD was considered as a covariable (F = 7.58; P = 0.025; d = 0.487). There were significant and indirect correlations of LnRMSSD TEST with VO 2max (r =-0.656, P = 0.02), ∆LnrMSSD with ∆VO 2max (r = -0.606, P = 0.037), and ∆LnrMSSD CV with ∆VENT (r = -0.790, P = 0.002). Conclusions: higher HRV scores suggest better cardiovascular adaptations due to higher training intensities, favoring HRV as a measure to optimize individualized training in professional runners. [ABSTRACT FROM AUTHOR]

• The effect of track components on the longitudinal resistance is briefly discussed. • Review of studies about ballast profile, ballast aggregates characteristics regarding longitudinal resistance. • Effect of vertical load on longitudinal resistance is studied. • The track behavior analyzed and the track longitudial resistance force and stiffness calculated. The longitudinal resistance of ballasted tracks is due to the longitudinal interaction of rail-fastener and ballast-sleeper. Longitudinal resistance is under the effect of various factors as well as the applied vertical load of the running train over the track structure. In this paper, the effect of vertical load on the longitudinal resistance of the ballasted railway track is experimentally and numerically investigated. First, the longitudinal resistance of a 3-m test panel with five B70 concrete sleepers under 0, 100, 200, and 300 kN vertical load were investigated. Second, a three-dimensional model of the track was developed using Abaqus software. Finally, the results of experiments and modeling were compared and the numerical modeling is validated based on tests' results. In each test, track longitudinal stiffness (TLS) and track longitudinal resistance force (TLRF) were calculated. According to laboratory results, TLS was increased by 3.36, 3.63, and 3.83 times with increasing the vertical load as 100, 200, and 300 kN, respectively. In the mentioned order the increment values for TLRF were increased 2.1, 2.74, 2.97 times. Likewise, the numerical results of TLRF for the above-mentioned load order illustrated increasing values as high as 2.1, 2.6, and 2.81 times, respectively. [ABSTRACT FROM AUTHOR]

Abstract: Objective: The aim of this study was to analyze the effect of running retraining on the recovery of the knee''s functional and muscular properties after anterior cruciate ligament (ACL) reconstruction. Methods: Eighty-five athletes who had undergone ACL reconstruction surgery were selected randomly to receive, or not to receive, controlled running training based on interval training and speed exercises. The effect of retraining was measured by the evolution of the knee''s isokinetic strength deficit and progress (at angular speeds of 60 and 180°/s), the knee laxity parameters and the score on the Lysholm Knee Scale from the 4th to the 6th month after the surgery. Forty subjects were retrained and compared with 40 control-group subjects. The effect of the retraining program was studied in terms of the type of ACL reconstruction and the effect of time. Results: After retraining, no difference was found for isokinetic knee strength deficit and progress, knee laxity and Lysholm Knee Score. The isokinetic strength deficit was influenced mainly by the type of ACL reconstruction. Conclusion: It would seem that running retraining has an insufficient effect on the muscular and functional recovery after ACL reconstruction, despite the fact that this type of training is well-tolerated. [Copyright &y& Elsevier]

• Full-scale tests were carried out on a fast streamlined train in crosswinds. • Aerodynamic loads were obtained by discrete integration of pressure differences. • Means and fluctuations of aerodynamic loads were obtained by data processing. • Fluctuations of aerodynamic coefficients are due to oscillations of wind speed. • Dominant frequencies of aerodynamic coefficients are at Strouhal numbers of 0–0.4. Unsteady aerodynamic loads have a significant influence on the running safety of a train in crosswinds. Full-scale tests were carried out to measure the pressure on a fast streamlined train in crosswinds, and the unsteady aerodynamic loads were obtained by the discrete integration of the pressure to assess the influence of different crosswinds on the loads. The maximum wind speed was 34.0 m/s in the full-scale tests, and the maximum turbulence intensity was 0.202. The means and fluctuations of the side force coefficient, lift coefficient, and rolling moment coefficient around the lee rail at different yaw angles were studied. The means first increased and then decreased with the increase in the yaw angle, and the maximum values occurred in the range of 54.5°–59.6°. The coefficients of variation of the aerodynamic load coefficients were approximately twice the turbulence intensity, which indicated that the fluctuations of the aerodynamic load coefficients were due to the oscillations of the wind speed. For the frequency characteristics of the aerodynamic load coefficients, the most dominant frequencies were at Strouhal numbers of 0–0.4. [ABSTRACT FROM AUTHOR]

• State-of-the-art review on train running safety on bridges. • International normative criteria regarding the train running safety on bridges. • Review of the main derailment mechanisms and safety criteria. • Effects of natural hazards, crosswinds and earthquakes, in the train stability. • Influence of track defects and induced deformations in the train stability. Train running safety is a major concern among railway engineers, since a derailment may cause significant personal and material damages. This problem becomes more important if the derailment occurs on bridges, especially at high-speeds, where the consequences may be even worse. The sudden development of high-speed (HS) railway networks that occurred at the end of the 20th century and beginning of the 21st century demanded the construction of new lines with large curve radii in order to fulfill the design requirements of this type of transport. By adding this fact to the orography constraints and, in some cases, to constraints related with the lack of construction area and with the high costs of expropriation, several HS lines started to be developed with more than 75% of their length built over viaducts and bridges. Naturally, this relatively new reality led to a significant increase in the probability of a train being exposed to natural hazards that might jeopardize its stability when it is running over an elevated structure. Hence, this paper aims to present a comprehensive literature review of the problematic associated with the train running safety assessment on bridges. The existing normative criteria from different regions of the world related to this topic are summarized in a first stage. Then, the paper gives a brief description of the available train-bridge interaction models needed to explicitly assess the traffic stability, followed by a presentation of the running safety indexes used to assess the derailment risk. Finally, the available applications regarding the traffic stability against different sources of excitation are systematically reviewed and guidance to future research work on this topic is provided. [ABSTRACT FROM AUTHOR]

In this study, a train model and a refined three-dimensional(3D) finite element (FE) model were combined to predict the environmental vibration induced by running trains in the surroundings. A half-train model and a 3D rail-track-soil FE model are established, in which the connection mode of rail and fastener has also been studied. The vibration of the train and refined 3D FE ground model are predicted simultaneously, and the solution process is realised by an interactive and iterative calculation method, considering also the vertical track irregularity. The computational time is basically the same as the method of simulating train loads with a set of moving concentrated forces. The results of the comparative studies carried out show that the predicted vibrations are in good agreement with the measured values, verifying the feasibility and correctness of the proposed method. Finally, the verification of the proposed method is carried out against experiment measurement. [ABSTRACT FROM AUTHOR]

• The generation mechanism of nonlinear contact between CRTS II track and bridge is discussed. • Method for investigating contact behaviors between CRTS II track and bridge is proposed. • The distributions and changes of gaps between CRTS II track and bridge are investigated. • Although the deformation at settlement pier location is the largest, the deformation at adjacent pier location is more sensitive to pier settlement. Due to the discontinuity of bridges and the continuity of the CRTS (China Railway Track System) II track, gaps usually appear between CRTS II track and bridge subject to pier settlement in practical engineering. Aiming at the influence of pier settlement on the contact behaviors between CRTS II track and bridge, the generation mechanism of the contact behaviors is primarily discussed in this work. On this basis, an accurate train-CRTS II track-bridge dynamic model is established by considering the nonlinear contact property between concrete base and deck in detail. Then the nonlinear contact behaviors between CRTS II track and bridge are investigated from static and dynamic perspectives adopting the established model. Result show that the proposed methodology is effective in studying the contact behaviors between CRTS II track and bridge. The nonlinear contact behaviors are obviously affected by pier settlement and running train. From the static perspective, pier settlement greatly affects the contact behaviors between base and deck around the settlement pier (SP) and the adjacent pier (AP) locations. The lengths of gaps and the contact force at AP location increase approximately linearly with the change of pier settlement. Even though the deformation at SP location is the largest, the deformation at AP location is more sensitive to pier settlement. From the dynamic perspective, influences of running train on the nonlinear contacts at AP locations are much larger than that at other locations. The length of Gap 2 (gap at AP location on the bridge with settlement) is most sensitive to running train. [ABSTRACT FROM AUTHOR]

• The generation mechanism of contact between CRTS II slab track and bridge is discussed. • The method for investigating nonlinear contact behaviors between CRTS II slab track and bridge is proposed by considering a detained and nonlinear contact relationship between concrete base and deck. • The distributions and changes of gaps between CRTS II slab track and bridge subject to time-dependent bridge deformation are investigated. Concrete creep and concrete shrinkage are unavoidable in the operation of concrete bridges in high-speed railways, which lead to bridge deformation and then cause gaps between CRTS (China Railway Track System) II slab track and bridge. Aiming at the dynamic contact between CRTS II slab track and bridge due to time-dependent effect of bridge and its influence on train-track-bridge interaction, this work proposes a method for investigating this dynamic contact behavior after exploring its generation mechanism. Adopting the established model, the nonlinear contacts between CRTS II slab track and bridge are deeply analyzed from static and dynamic perspectives. Finally, the influence of the dynamic contact on the train-track-bridge interaction is also investigated. Results show that the proposed methodology is effective in studying the contact behaviors between CRTS II slab track and bridges subject to time-dependent effect of bridge. Gaps appear at beam-end locations, and sharp contact behaviors are aroused at the locations of gap-edges. The length of gap is greatly decreased by running train. Creep and shrinkage have great influence on the train vibrations, while have almost no effect on track-bridge vibrations. Interlayer forces of track are obviously affect by bridge deformation and running train. [ABSTRACT FROM AUTHOR]