Dynamic performance of heavy-haul combined train applying emergency braking on straight line

A heavy-haul train-track coupled model is developed. Taking the emergency braking of the 2×104 t combined train as example, the train longitudinal impulse, the coupler dynamic behaviors and wheel-rail interactions of vehicles distributing in the different positions are analyzed. The results indicate that under the coupler compressing forces, the couplers of middle locomotives may tilt to the free swing limits, which induces the unidirectional tilt of their connected wagon couplers. Consequently, the coupler longitudinal forces produce the lateral components, and then affect the wheel-rail dynamic interaction. The performance of the middle locomotive and their neighboring freight wagons deteriorate significantly, becoming the most dangerous parts in the combined train. The wagons disconnecting with the locomotives can basically keep their couplers to stabilize in the centering positions, even though the maximum coupler longitudinal force acts on it. And its corresponding running safety also has little changes.

Adaptive H_(∞)Filtering Algorithm for Train Positioning Based on Prior Combination Constraints

To solve the problem of data fusion for prior information such as track information and train status in train positioning,an adaptive H∞filtering algorithm with combination constraint is proposed,which fuses prior information with other sensor information in the form of constraints.Firstly,the train precise track constraint method of the train is proposed,and the plane position constraint and train motion state constraints are analysed.A model for combining prior information with constraints is established.Then an adaptive H∞filter with combination constraints is derived based on the adaptive adjustment method of the robustness factor.Finally,the positioning effect of the proposed algorithm is simulated and analysed under the conditions of a straight track and a curved track.The results show that the positioning accuracy of the algorithm with constrained filtering is significantly better than that of the algorithm without constrained filtering and that the algorithm with constrained filtering can achieve better performance when combined with track and condition information,which can significantly reduce the train positioning error.The effectiveness of the proposed algorithm is verified.

The effect of controllable train-tail devices on the longitudinal impulse of the combined trains under initial braking

The 20,000-ton combined train running has greatly promoted China’s heavy-haul railway transportation capability. The application of controllable train-tail devices could improve the braking wave of the train and braking synchronism, and alleviate longitudinal impulse.However, the characteristics of the controllable train-tail device such as exhaust area, exhaust duration and exhaust action time are not uniform in practice, and their effects on the longitudinal impulse of the train are not apparent,which is worth studying. In this work, according to the formation of the Datong-Qinhuangdao Railway, the train air brake and longitudinal dynamics simulation system(TABLDSS) is applied to establish a 20,000-ton combined train model with the controllable train-tail device, and the braking characteristics and the longitudinal impulse of the train are calculated synchronously with changing the air exhaust time, exhaust area, and action lag time under initial braking. The results show that the maximum coupler force of the combined train will decrease with the extension of the continuous exhaust time, while the total exhaust time of the controllable train-tail device remains unchanged;the maximum coupler force of the combined train reduces by32.5% with the exhaust area increasing from 70% to 140%;when the lag time between the controllable train-tail device and the master locomotive is more than 1.5 s, the maximum coupler force of the train increases along with the time difference enlargement.

System integration and innovation of operating 20 kt combined heavy-haul train on Datong-Qinhuangdao line

Datong-Qinhuangdao line, as the first electrified double-track heavy-haul line dedicated to coal transport in China, extends from Datong in the west, and reaches Qinhuangdao in the east, opened to traffic in December, 1992, totaling 653 km with the designed annual traffic volume of 1×108 t. In order to meet the demands of national economic development, the transport capacity of the line must be enhanced greatly. Depending on independent innovation, MOR, for the first time in the world,realizes the integration between GSM-R and Locotrol, the integration between 800 MHz digital radio and Locotrol, and the integration between a single set of Locotrol and SS4 locomotive. Meanwhile, CR develops equipment portfolio for heavy-haul through combining 2 high power locomotives of HXD series (means harmony) with controllable EOT. Relying on integration and innovation, it succeeds in operating 20 kt-level combined heavy-haul train on Datong-Qinhuangdao line, which tripled the annual traffic volume of the line from 1×108 t in 2002 to 3×108 t in 2007.

Analysis of the different locomotive wireless multi-traction synchronous control systems for heavy-haul combined trains and their performance

This paper looks at the heavy-haul combined train composed of different types of locomotives and its distributed power control system with a combination of 800 MHz and TD-LTE wireless communication.It analyses some key characteristic parameters that affect the synchronism and communication of the differential wireless multi-traction synchronous control systems for heavy-haul combined trains.At the same time,in order to reduce the latency of instruction and information transfer between different types of locomotives,improve the time-limit certainty of wireless transmission and optimize the control quality of multi-traction control systems for heavy-haul combined trains,a synchronism optimization strategy based on the Markov decision process on the basis of Petri networkconstruction is proposed.Relevant experiments and tests are carried out to verify the effectiveness of the synchronism optimization of the control system,which provides a guarantee for improving the differential wireless multi-traction synchronous control system for combined trains and optimizing train control.

Simulation study on the influence of longitudinal dynamic force on extreme-long heavy-haul trains

Purpose–The objective of this study is to investigate the impact of longitudinal forces on extreme-long heavy-haul trains,providing new insights and methods for their design and operation,thereby enhancing safety,operational efficiency and track system design.Design/methodology/approach–A longitudinal dynamics simulation model of the super long heavy haul train was established and verified by the braking test data of 30,000 t heavy-haul combination train on the long and steep down grade of Daqing Line.The simulation model was used to analyze the influence of factors on the longitudinal force of super long heavy haul train.Findings–Under normal conditions,the formation length of extreme-long heavy-haul combined train has a small effect on the maximum longitudinal coupler force under full service braking and emergency braking on the straight line.The slope difference of the long and steep down grade has a great impact on the maximum longitudinal coupler force of the extreme-long heavy-haul trains.Under the condition that the longitudinal force does not exceed the safety limit of 2,250 kN under full service braking at the speed of 60 km/h the maximum allowable slope difference of long and steep down grade for 40,000 t super long heavy-haul combined trains is 13‰,and that of 100,000 t is only 5‰.Originality/value–The results will provide important theoretical basis and practical guidance for further improving the transportation efficiency and safety of extreme-long heavy-haul trains.

Monitoring energy usage of heavy-haul iron ore trains with on-board energy meter for improving energy efficiency

Purpose-For billing purposes,heavy-haul locomotives in Sweden are equipped with on-board energy meters,which can record several parameters,e.g.,used energy,regenerated energy,speed and position.Since there is a strong demand for improving energy efficiency in Sweden,data from the energy meters can be used to obtain a better understanding of the detailed energy usage of heavy-haul trains and identify potential for future improvements.Design/methodology/approach-To monitor energy efficiency,the present study,therefore,develops key performance indicators(KPIs),which can be calculated with energy meter data to reflect the energy efficiency of heavy-haul trains in operation.Energy meter data of IORE class locomotives,hauling highly uniform 30-tonne axle load trains with 68 wagons,together with additional data sources,are analysed to identify significant parameters for describing driver influence on energy usage.Findings-Results show that driver behaviour varies significantly and has the single largest influence on energy usage.Furthermore,parametric studies are performed with help of simulation to identify the influence of different operational and rolling stock conditions,e.g.,axle loads and number of wagons,on energy usage.Originality/value-Based on the parametric studies,some operational parameters which have significant impact on energy efficiency are found and then the KPIs are derived.In the end,some possible measures for improving energy performance in heavy-haul operations are given.

Improvement of heat-tolerance by training I. Evaluation of effects of combined of march and cross-country race on heat-tolerance

in order to improve the acquired level of heat acclimatization (HA) by training, on the basis of singlemode march training (SMT) or single-mode cross-country race training (SCT) , combined training method of march and cross-country race in the heat was adopted in this experiment ,and the effect of the training on heat tolerance was analyzed. Eight young males were asked to perform a simulated SMT and SCT for 90 min on a treadmill in a hot climate chamber (Td 32. 7℃ , WBGT 28. 4℃ ) once daily for 10 to 12 d within two weeks. The results showed that rectal temperature (Tr) was reduced by 0. 61℃ , heart rate (Hr) by 8. 5 b/min,sweat volume (SV)by 0. 220 kg, physiological strain index (PSI)by 0. 620,systolic pressure (SP)and diastolic pressure (DP) had a little change, pulse pressure (PP) and stroke volume (StV) increased , and cardiac output (CO) decreased a little at the middle stage and increased at the late stage due to Hr change. The standardized bicycle ergometer test (SBE test) in the heat (Td 37℃)has proved that these physiological indexes post-training had significant improvements ,as compared with those pre-training, suggesting that the combined training could raise heat-tolerance and was superior to the SMT in improving acquired heat acclimatization in same training duration and times , and to the SCT in regulating body temperature and cardiovascular function and in prolonging heat tolerance duration.

Combined Training in the Treatment of Type 2 Diabetes Mellitus: A Review

This study aimed to review combined training (CT) effects on HbA1c levels in patients with T2DM. Searches were conducted in PubMed via MEDLINE and Google Scholar. Of the 14 selected studies, 11 found reductions in HbA1c levels. The interventions that performed both aerobic and resistance training in the same sessions were highlighted. In aerobic training, the best results were in the interventions between 30 and 45 minutes per session, with intensities between 60 and 80% of maximal parameters. In resistance training, the interventions with sets from 8 to 12 repetitions with intensities of 80% and 60% of 1RM respectively, or prescribed by maximal repetitions, were highlighted. We conclude that CT can result in better glycaemic control than AT and RT conducted alone.

Intervention Study on the Exercise Order of Combined Aerobic ＆ Resistance Training in the Elderly

When combined aerobic and resistance training into the same session is performed, the exercise order may lead to different effects with respect to factors such as muscle strength, hormone responses, energy metabolism, and vascular function. The purpose of this study was to examine the effects of exercise order of combined aerobic and resistance training into the same session on body composition, muscle strength and arterial stiffness in the elderly. Thirty-one elderly subjects （70.5 ± 3.5 years） were randomly assigned to 3 groups; AR： aerobic before resistance training, RA： resistance before aerobic training and CON： no training. Subjects trained 2 times per week for 10 weeks. Resistance training consisted of 3 sets of 8-12 repetitions for 5 different exercises, 70%-80% of one repetition maximum （1RM）. Aerobic exercise consisted of cycling at 60% of heart rate reserve （HRR）. Significant interaction effects were observed in body fat percentage （P 〈 0.01） and 1RM （P 〈 0.01）. However, no significant differences were observed between AR and RA. In contrast, pulse wave velocity （PWV） significantly reduced in the RA （8.8± 2.1 m/s to 7.6 ± 1.9 m/s, P 〈 0.05）, while PWV increased in the AR （7.9 ± 2.8 m/s to 10.0 ± 2.6 m/s, P 〈 0.01）, and there was significant difference between AR and RA （P 〈 0.05）. In conclusion, no effects of the exercise order were observed in body composition and muscle strength. However, aerobic exercise after resistance training reduced arterial stiffness and difference of exercise order was observed.

Dynamic effect of heavy-haul train on seismic response of railway cable-stayed bridge

This paper focuses on understanding and evaluating the dynamic effect of the heavy-haul train system on the seismic performance of a long-span railway bridge. A systematic study on the effect of heavy-haul trains on bridge seismic response has been conducted, considering the influence of vehicle modeling strategies and dynamic characteristics of the seismic waves. For this purpose, the performance of a long-span cable-stayed railway bridge is assessed with stationary trains atop it, where the heavy-haul vehicles are modeled in two different ways: the multi-rigid body model with suspension system and additional mass model. Comparison of the bridge response in the presence or absence of the train system has been conducted, and the vehicle loading situation, which includes full-load and no-load, is also discussed. The result shows that during the earthquake, the peak moment of the main girder and peak stress of stay cables increase by 80% and by 40% in the presence of fully loaded heavy-haul trains, respectively. At the same time, a considerable decrease appears in the peak acceleration of the main girder. This proves the existence of the damping effect of the heavy-haul train system, and this effect is more obvious for the fully loaded vehicles. Finally, this paper proposes an efficient vehicle modeling method with 2 degrees of freedom(DOF) for simplifying the treatment of the train system in bridge seismic checking.

Effective Combination of Physical Education and Sports Training

The sports teaching and the movement training all is Our country University sports important constituent, between both in essentially already has one kind to promote and the development relations mutually, simultaneously also is the sports academic circles always disputes the continuous topic. But speaking of some kind of degree, its both goal is and improves university student＇ s physical quality for the full scale development, enables the student to grasp the basic sports knowledge and the sports skill. Between the two only together to develop, in order to better promote the healthy development of college sports and therefore, this article on the physical education and sports training interactive development strategy in-depth discussion.

结合型式对地铁车站上盖物业的振动响应影响

为研究地铁振动对不同结合类型地铁车站及其上方的动力反应影响,基于地铁车站与上盖物业连接型式的主要承载区别,提出“软结合”“硬结合Ⅰ”“硬结合Ⅱ”3种结合型式;然后,采用车-轨耦合模型得到列车荷载谱,利用有限差分软件FLAC^(3D)建立地铁车站-上盖物业数值仿真模型,并与实测数据进行对比,验证数值仿真模型与参数的正确性;最后,基于数值仿真,从时域、频域出发,研究3种结合型式下上盖物业的振动响应.研究结果表明:软结合型式下站厅层到上盖物业一层加速度峰值减小69.10%,硬结合Ⅰ型减小2.08%,硬结合Ⅱ型增大2.94%,硬结合型式下上盖物业振动加速度较软结合型式大;3种结合型式下上盖物业振动的频率主要在40~90 Hz,且对于上盖物业同一楼层,振动随距振源距离的增大而逐渐减小;软结合型式下上盖物业一层加速度级最大值为68.2 dB,较站厅层减小11.3 dB;硬结合Ⅰ型、硬结合Ⅱ型的上盖物业加速度级最大值分别为83.4、79.4 dB;地铁振动造成上盖物业附加第一主应力很小,且在向上传播过程中衰减很快;从站厅层到上盖物业,软结合型式第一主应力衰减85.81%,硬结合Ⅰ、Ⅱ型式分别衰减63.46%、72.27%,间隔土对附加应力有明显衰减作用.在地铁实际建设工程中建议选用软结合型式.

体教融合背景下陕北高校篮球运动队管理系统的设计研究

从校园篮球的推进到落实,从体教分离到体教融合,体现了体育与教育融合是时代所趋。该文主要在体教融合背景下,通过走访延安市各大高校,了解学生希望达成的目标和现在训练过程中遇到的困难。针对这些问题,利用互联网和大数据对高校篮球校队运动员开展训练日程管理,方便教师安排训练任务及跟踪运动员的训练任务完成情况,不断提高高校校队篮球运动员的训练质量。最后,通过SWOT分析,验证了该训练管理系统的有效性和可行性,为高校篮球运动队的可持续发展提供了有益的参考和借鉴。

基于虚实结合的雷达操作训练方法研究

针对雷达训练中缺环境、缺装备的现状,提出了基于虚实结合的雷达操作训练方法。首先,分析了虚实结合概念的内涵;其次,研究了实体雷达与虚拟环境和虚拟雷达与实体环境两种虚实结合的交互方法;最后,结合具体训练需求,在同一场景中分析了实-实、实-虚、虚-实、虚-虚四种雷达与环境交互方法在雷达训练中的应用。

育训结合模式下高职院校社会培训路径研究

人才培养、科学研究、社会服务是高职院校的基本职能,社会培训是高职院校社会服务的重要内容。高职院校社会培训存在师资缺乏实践经验、培训服务供需错位、管理方式简单粗放、企业缺乏参与热情等突出问题,为此应从更新思想观念、拓宽培训渠道、整合教学资源、加大资金投入、强化双师素质几方面优化高职院校社会培训路径。

CBL联合PBL在神经外科住院医师规范化培训教学中的应用研究

目的:在神经外科住院医师规范化培训中按照规范化培训的大纲要求,引入特定情景的临床案例,并结合问题引导式的教学方法,探讨这一教学模式在临床规培生教学中的效果。方法:纳入某院神经外科规范化培训并自愿报名的40名学员,随机分成两组,对照组采用传统的教学方法授课,观察组采用案例分析(CBL)结合问题导向(PBL)联合教学,比较两种方法的教学效果。结果:观察组学员在出科考核多项环节中(自主学习能力,问题解决能力,团队合作能力以及综合考核)成绩明显优于对照组(P<0.05),同时观察组学员对教学模式评分也高于对照组(P<0.05)。结论:CBL联合PBL在神经外科规范化培训中能更好地提高学员对理论知识的理解和掌握,获得了广大学员的欢迎。

基于Vague集犹豫量化的机舱团队协作式评估方法

针对现有机舱团队协作评估方法不统一且主观随意性太强的缺陷,提出一种基于Vague集犹豫量化的新型评估方法。从机舱团队协作的角度对影响评估的各因素进行提取,采用集合相似系数对重要协作指标量化,并采用C-OWA算子赋权法和变异系数法确定主客观权重,利用最小鉴别信息原理求得组合权重,结合Vague集的犹豫量化特点,通过机舱团队实际操作数据与Vague集评估标准得到各指标的定性评估Vague集,并利用集合相似度分析实现机舱团队协作的综合评估。实例计算结果表明:相对于传统的评估方法,在个体完成度的基础上加入具有犹豫团队协作因素的方法,能对评估结果的犹豫度进行较好地刻画,也能很好地实现定量与定性之间的转化,是一种有效且优越的机舱团队协作式评估方法。

新时代复合型特殊教育教师培养的创新实践——以杭州师范大学特殊教育专业为例

“复合型”特殊教育教师是融合教育、教康结合等特殊教育发展趋势下对新时代特殊教育教师培养的要求。在此背景下,杭州师范大学特殊教育专业开始探索高质量复合型特殊教育教师的培养,凝练出“精特教、懂融合、知康复”的培养模式,设置“特殊教育、融合教育、教育康复、教师基本素养”四大主线课程,打造“跨学科教师团队+核心专业教师团队+社会实践教师团队”组成的“三元”师资团队,与特殊教育学校、融合教育学校、康复机构等实施协同教学和评价,构建“全程化、融入式、多样性”的实践体系。

组合训练在足球运动训练中的应用探索

随着现代足球竞技水平的日益提高,单一的训练方法已经难以满足运动员全面发展的需求,传统的训练方式往往过于强调某一项技术或某一身体素质的提升,而忽视了其他方面,导致运动员在实际比赛中难以发挥出全部实力。因此,如何将多种训练元素有机地结合起来,使运动员在技术、战术、身体、心理等多个层面都得到均衡的发展,成为当今足球教练追求的目标。组合训练旨在通过融合各种训练方法,提高球员的综合能力。并且,随着科技的进步,多媒体、数据分析和生物力学等现代技术也被引入组合训练中,使之变得更加科学、更加系统。这种训练模式的探索与应用,不仅能够为提高球员的竞技水平提供新的思路,还能够为足球训练方法的研究提供有价值的参考。