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The normalized operation of 30,000-ton heavy-haul trains is of significant importance for enhancing the transportation capacity of heavy-haul railways. However, with the increase in train formation size, traditional braking strategies result in excessive longitudinal impulse when combined pneumatic and electric braking is applied on long, steep gradients. This presents a serious challenge to the braking safety of the train. To this end, this paper establishes a longitudinal dynamic model of a 30,000-ton heavy-haul train based on vehicle system dynamics theory, and validates the model's effectiveness through line test data. On this basis, the influence of two braking parameters, namely, the distribution of the magnitude of the electric braking force and the matching time of pneumatic braking and electric braking, on the longitudinal dynamic behavior of heavy-haul trains is studied. Thereby, an optimized combined pneumatic and electric braking strategy is formulated to reduce the longitudinal impulse of the trains. The results show that setting reasonable braking parameters can effectively reduce the longitudinal impulse, with the braking matching time having a significant impact on the longitudinal impulse. Specifically, when using a strategy where the electric braking forces of three locomotives are set to 90 kN, 300 kN, and 300 kN, with a 30 s delay in applying the electric braking force, a better optimization effect is achieved. The two proposed braking strategies reduce the maximum longitudinal forces by 20.27% and 47.83%, respectively, compared to conventional approaches. The research results provide effective methods and theoretical guidance for optimizing the braking strategy and ensuring the operational safety of 30,000-ton heavy-haul trains. [ABSTRACT FROM AUTHOR]

During the structural qualification testing of propellant tanks of a liquid engine, one M12 nut made of 35NCD16 steel used for the testing was found broken. Structural qualification testing was conducted to verify the design adequacy of tanks in human-rated missions. A detailed metallurgical investigation was conducted on the failed nut, bolt, and washers to determine the underlying cause of fracture. This investigation included detailed visual inspections, hardness testing, as well as microstructural characterization using tools such as the optical and scanning electron microscopy. In a comparative study, the nuts adjacent to and diametrically opposite from the failed assembly were examined along with exemplar nuts. Fractographic analysis revealed dimpled rupture characteristics with substantial inclusions in the longitudinal direction of the nut. A detailed investigation of the failed nut revealed long, aligned non-metallic inclusions, primarily mixed oxides of Mn, Si, and Cr. These inclusions were found to be the underlying cause of nut fracture below maximum tensile stresses. [ABSTRACT FROM AUTHOR]

This essay examines the underexplored connections between articulations of technological modernity and the formation of future national subjects in Republican China by analyzing the fictional figures of locomotives in children's magazines from the 1930s, in which the machines are personified as having life, awareness, willpower, thought, and emotion. Through close readings of fairy tales and nursery rhymes that engage readers through the sonic, mechanical, and visual traits of trains, as well as creative works written by Chinese children, I argue that the anthropomorphized trains served as active agents in shaping the subjectivity of the younger Chinese generation. These narratives not only encouraged children to empathize with the locomotive protagonists but also created an immersive intermedial experience, which allowed children to internalize and embody the trains' characteristics as positive traits associated with youth and the working class. Aside from shedding light on the scholarship of children's literature, this paper also brings attention to the technological medium through which individual and collective agency were imagined and materialized in modern China. [ABSTRACT FROM AUTHOR]

In the realm of artificial intelligence, fuzzy logic emerges as a valuable tool for predicting thoracic disorders, encompassing various medical conditions affecting the heart, lungs, mediastinum, esophagus, chest wall, major vessels, and diaphragm. This predictive system relies on an objective fuzzy modeling approach, which has proven highly effective in enhancing accuracy by integrating clustering algorithms with fuzzy system identification. To train this predictive engine, historical data pertaining to common thoracic disorders is gathered from reliable online sources. Relevant data are meticulously collected and processed, retaining only essential inputs for the prediction system. The recorded data undergoes logical processing and is normalized through a fuzzification process. The prediction model leverages the power of DenseNet, particularly in "reading chest X-rays," enabling the identification and localization of prevalent disease patterns using image-level labels alone. The performance of the Modified Fuzzy-Based Neural Networks for predicting common thoracic diseases is remarkable, achieving an impressive accuracy rate of 96% with just 10 training epochs and with training and validation loss consistently below 5%. This innovative approach seamlessly combines objective fuzzy modeling with DenseNet utilization for thoracic disease prediction. By integrating historical data, meticulous preprocessing, normalization, disease prediction, and de-fuzzification, the system excels in recognizing and precisely locating frequently encountered thoracic diseases, offering a high degree of accuracy in diagnosis and assessment. [ABSTRACT FROM AUTHOR]

Introduction. The paper considers equipping rolling stock with new lightweight wheel stops of increased reliability, as well as the use of the drag shoes on space intervals, including abnormal situations.Materials and methods. The authors performed field tests to compare the performance of lightweight wheel stops TM 37.10.2016 and hump drag shoes 8739.00. The paper determined the tractive force for moving a empty car train and loaded car train equipped with drag shoes.Results. The paper analyses the securing of railway rolling stock with wheel stops on space intervals with different gradients and different weights of trailing rolling stock. The paper describes the developed methodology of emergency withdrawal of a multiple unit rolling stock with a wedged wheel pair using wheel stops and determines the ultimate sliding distance of the wedged wheel pair compared to the hump drag shoes. The paper established that withdrawing the electric rolling stock from the space interval with the wedged wheel pair requires 4 times more wheel stops than the hump drag shoes.Discussion and conclusion. The authors shown that traction rolling stock permits the practical replacement of hump drag shoes 8739.00 currently in use with wheel stops TM 37.10.2016. The braking characteristics of wheel stops and hump drag shoes only differ during the short initial period of paint abrasion on the rubbing surface of the wheel stop skids. Since the drag shoes for rolling stock are intended for emergency, their rubbing surface must not be painted.

Mobile British artisans played a key role in the global diffusion of industrialization, taking their skills to Continental Europe and the USA. While research in recent decades among those who might be classed as minor innovators or tweakers has increased our knowledge and understanding of their contribution to this process, less is known about those skilled tradespeople who might be classed as implementers, in other words, those who proved capable of constructing, installing and operating new industrial plant and machinery but are not noted for their innovations. This article is the study of the life and context of William Harman, a highly mobile individual involved in the construction of steamships and locomotives and whose career took him from his home near Hull to France and across the United States as the frontier moved westwards. [ABSTRACT FROM AUTHOR]

The bogie is a critical component of high-velocity trains. As train velocity rises, the operational quality is increasingly influenced by aerodynamic forces. The aerodynamic characteristics of bogies significantly impact the safety of train operations. This article examines a real high-velocity train model, constructing a 3-group train model, and developing a mathematical model of high-velocity train operation on open lines. Using three-dimensional steady-state Navier–Stokes equations, the flow field characteristics, pressure spread, aerodynamic forces, and torque characteristics on the bogie and body of high-velocity locomotives operating at velocities of 200 km/h, 250 km/h, 300 km/h, and 350 km/h are calculated, with measurement spots set to study the trend of pressure variation with train velocity. The research findings indicate that pressure at the same location on the body surface rises with vehicle velocity, with a quadratic link between the two. The uneven pressure spread between two bogies of the same vehicle and between two axles of the same bogie indicates that aerodynamic forces can cause axle load transfer in high-velocity trains. The highest values of aerodynamic resistance and lift happen at the front bogie, and the resistance and lift of both a single carriage and the entire vehicle increase with velocity, following a quadratic relationship. The highest nodding torque of the train body occurs on one vehicle, while the highest nodding torque of the bogie occurs on the 6th bogie, with both torques increasing with velocity, also in a quadratic relationship. [ABSTRACT FROM AUTHOR]

Waste lubricant oil (WLO) is always found in motor vehicle repair shops. Utilizing WLO by distilling it will provide benefits. For this reason, WLO was distilled in this research. Several characterizations were conducted to determine the viscosity, density, low heat value (LHV), and flash point of WLO and distillation products (DP). The DP is less viscous, denser, LHV, and flash point than WLO. The DP was mixed with Pertamina Dex (0, 5, 10, and 15 vol.%) and then filled into the fuel tank for the engine performance test. The present experiment utilized a compression-ignition (CI) engine to measure performance. CI engine speed variations were carried out at 1000, 1500, 2000, and 2500 rpm to see the influence of the mixed fuel on torque, power, specific fuel consumption (SFC), thermal efficiency, and smoke opacity. The increase in CI engine speed leads to an increase in torque, power, thermal efficiency, and smoke opacity, but at the same time, SFC decreases to 2500 rpm. Increasing the DP content in the mixed fuel decreases torque, power, SFC, thermal efficiency, and increased smoke opacity. [ABSTRACT FROM AUTHOR]

In the context of locomotive traction systems, the power electronic traction transformer (PETT) represents a pivotal component, fulfilling essential functions pertaining to electrical isolation and power control. The majority of existing PETT prototypes employ a combination of a cascade structure and an ISOP structure. The aforementioned scheme effectively reduces the voltage withstand level of the power devices on the input side, yet it also necessitates the utilisation of a greater number of power devices and passive components within the PETT. In order to further reduce the number of power devices used, this paper proposes a new cascaded PETT design. The proposed PETT will adopt a scheme combining a cascade structure and a hardware circuit multiplexing. This paper first analyses the operation principle of the new circuit under non-single frequency PWM control. It then derives the design equations for some hardware parameters and control circuits. Finally, it verifies the effectiveness of the proposed PETT through simulation analysis. [ABSTRACT FROM AUTHOR]

Background: Understanding the gait pattern of patients eligible for total hip arthroplasty (THA) due to hip osteoarthritis (OA) offers valuable information for improving locomotive syndrome (LS). This study aims to measure the gait patterns of THA-eligible patients using an optical motion capture system and to analyze these patterns using principal component analysis (PCA). Additionally, this study examines the relationship between THA-induced gait patterns and LS. Methods: This before-after study included 237 patients who underwent unilateral primary THA due to hip OA. The primary outcome measures were spatiotemporal gait parameters. Secondary outcome measures included three LS risk tests: a stand-up test, a two-step test, a 25-question Geriatric Locomotive Function Scale (GLFS-25), and total clinical decision limits stages. PCA was performed using 16 spatiotemporal gait parameters collected before and three months after THA. Principal components (PC) were selected to achieve a cumulative contribution rate of 90% (0.9) or higher. Each summarized PC was compared using a paired t-test before and three months after THA. Furthermore, multiple regression analysis was conducted to determine how changes in each PC between before and three months after THA related to changes in the four LS evaluation items. Results: PCA identified three principal components (PC1, PC2, PC3) that accounted for a cumulative contribution rate of 0.910 using 16 spatiotemporal gait parameters. When comparing before and three months after THA for all three PCs, significant differences were observed in each PC (p < 0.001), with overall walking ability and stance phase being higher three months after THA than before THA, while the asymmetry of support time was lower three months after THA. The results of multiple regression analysis revealed that PC1, PC2, and PC3 were the most influential factors in total clinical decision limits stage. For each LS risk test, the factors related to the stand-up test were identified as PC1, PC2, and PC3, while the factors related to the two-step test were identified as PC1 and PC2. The factors related to the GLFS-25 were also identified as PC1 and PC2. Conclusions: The most important findings of this study indicate that the three PCs represent over 90% of the 16 spatiotemporal gait parameters, which are associated with total clinical decision limits stage and LS risk tests. The present results suggest that PC1 represents overall walking ability, PC2 represents the stance phase, and PC3 represents asymmetry of support time. Gait pattern characteristics, such as overall walking ability, stance phase, and asymmetry of support time, were clearly defined by these PCs. Regarding the relationship between PC and LS, all three PCs are related to total clinical decision limits stage. In addition, PC1 and PC2 related to all three LS risk tests, and PC3 related only to the stand-up test. [ABSTRACT FROM AUTHOR]

To measure the effectiveness of learning activities, intensive research works have focused on the process of competency building through the identification of learning stages as well as the setup of related key performance indictors to measure the attainment of specific learning objectives. To organize the learning activities as per the background and skills of each learner, individual learning styles have been identified and measured by several researchers. Despite their importance in personalizing the learning activities, these styles are difficult to implement for large groups of learners. They have also been rarely correlated with each specific learning stage. New approaches are, therefore, needed to intelligently coordinate all the learning activities while self-adapting to the ongoing progress of learning as well as to the specific requirements and backgrounds of learners. To address these issues, we propose in this paper a new framework for an intelligent management of the competency building process during learning. Our framework is based on a recursive spiral Assess-Predict-Oversee-Transit model that is orchestrated by a multi-agent system. This system is particularly responsible of enabling smart transitions between learning stages. It is also responsible of assessing and predicting the process of competency building of the learner and, then, making the right decisions about the learning progress, accordingly. Results of our solution were demonstrated via an Augmented Reality app that we created using the Unity3D engine to train learners on Air Conditioner maintenance. [ABSTRACT FROM AUTHOR]

Traction drives with vector control are widely used on mainline locomotives with induction motors. Traction motors can fail due to malfunctions that occur during the operation of locomotives. Real-time functional diagnostic systems are necessary to prevent the failure of traction motors. The implementation of such systems will allow to detect the occurrence of malfunctions in the traction motor at the initial stage and prevent the further development of the defect. In the work, a structural diagram of functional diagnostics for monitoring the condition of the rotor of an induction motor is proposed and an algorithm for its operation is developed. [ABSTRACT FROM AUTHOR]

This study addresses the issue of carbody hunting in an electric locomotive induced by low wheel-rail contact conicity. The main objective is to mitigate this unstable motion by optimising the location of yaw dampers while ensuring bogie stability under high conicity conditions. A field test was first conducted to observe the carbody hunting behaviour, and a detailed locomotive dynamics model was then developed and validated using experimental data. The impact of yaw damper locations on locomotive stability was investigated, taking into consideration different carbody modes. The findings reveal the mechanism behind the deterioration of carbody stability due to the yaw damper installation angle and two installation layouts were proposed to enhance the carbody stability. Comparisons were then made with traditional solutions using both linear and nonlinear analysis, and experimental validation confirmed the effectiveness of the optimised yaw damper locations in improving carbody stability. This research highlights the importance of optimising the yaw damper's location to suppress carbody hunting, providing valuable insights for railway engineers and offering a promising solution for enhancing stability in high-speed train. [ABSTRACT FROM AUTHOR]

Copyright of China Rubber Industry is the property of Editorial Office of China Rubber Industry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The problem of modelling and simulating traditional crafting actions is addressed, motivated by the goals of craft understanding, documentation, and training. First, the physical entities involved in crafting actions are identified, physically, and semantically characterised, including causing entities, conditions, properties, and objects, as well as the space and time in which they occur. Actions are semantically classified into a taxonomy of four classes according to their goals, which are shown to exhibit similarities in their operation principles and utilised tools. This classification is employed to simplify the create archetypal simulators, based on the Finite Element Method, by developing archetypal simulators for each class and specialising them in craft-specific actions. The approach is validated by specialising the proposed archetypes into indicative craft actions and predicting their results in simulation. The simulated actions are rendered in 3D to create visual demonstrations and can be integrated into game engines for training applications. [ABSTRACT FROM AUTHOR]

Copyright of Railway Construction Technology is the property of Railway Construction Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)