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Analysis on running safety of train on the bridge considering sudden change of wind load caused by wind

Tian ZHANG, He XIA, Weiwei GUO

《结构与土木工程前沿(英文)》 2018年 第12卷 第4期   页码 558-567 doi: 10.1007/s11709-017-0455-1

摘要: The calculation formulae for change of wind load acting on the car-body are derived when a train moves into or out of the wind barrier structure, the dynamic analysis model of wind-vehicle-bridge system with wind barrier is established, and the influence of sudden change of wind load on the running safety of the train is analyzed. For a 10-span simply-supported U-shaped girder bridge with 100 m long double-side 3.5 m barrier, the response and the running safety indices of the train are calculated. The results are compared with those of the case with wind barrier on the whole bridge. It is shown that the sudden change of wind load caused by wind barrier has significant influence on the lateral acceleration of the car-body, but no distinct on the vertical acceleration. The running safety indices of train vehicle with sectional wind barriers are worse than those with full wind barriers, and the difference increases rapidly with wind velocity.

关键词: wind barrier     sudden change of wind load     dynamic response     running safety     comfort    

Dynamic response of a long span suspension bridge and running safety of a train under wind action

GUO Weiwei, XIA He, XU You-lin

《结构与土木工程前沿(英文)》 2007年 第1卷 第1期   页码 71-79 doi: 10.1007/s11709-007-0007-1

摘要: A dynamic analysis model of a wind-train-bridge system is established. The wind excitations of the system are the buffeting and self-excited forces simulated in time domain using measured aerodynamic coefficients and flutter derivatives. The proposed formulations are then applied to a long rail-cum-road suspension bridge. The dynamic responses of the bridge and the train under wind action are analyzed. The results show that the lateral and rotational displacements of the bridge are dominated by wind, while the vertical by the gravity loading of the moving train. The running safeties of the train vehicles are much affected by wind. Under wind conditions of 30 40 m/s, the offload factors, derail factors and overturn factors of the train vehicles exceed the safety allowances, to which great attention should be paid.

关键词: rotational     offload     vertical     m/s     attention    

Evaluation of power regeneration in primary suspension for a railway vehicle

Ruichen WANG, Zhiwei WANG

《机械工程前沿(英文)》 2020年 第15卷 第2期   页码 265-278 doi: 10.1007/s11465-019-0571-9

摘要: To improve the fuel economy of rail vehicles, this study presents the feasibility of using power regenerating dampers (PRDs) in the primary suspension systems of railway vehicles and evaluates the potential and recoverable power that can be obtained. PRDs are configured as hydraulic electromagnetic-based railway primary vertical dampers and evaluated in parallel and series modes (with and without a viscous damper). Hydraulic configuration converts the linear behavior of the track into a unidirectional rotation of the generator, and the electromagnetic configuration provides a controllable damping force to the primary suspension system. In several case studies, generic railway vehicle primary suspension systems that are configured to include a PRD in the two configuration modes are modeled using computer simulations. The simulations are performed on measured tracks with typical irregularities for a generic UK passenger route. The performance of the modified vehicle is evaluated with respect to key performance indicators, including regenerated power, ride comfort, and running safety. Results indicate that PRDs can simultaneously replace conventional primary vertical dampers, regenerate power, and exhibit desirable dynamic performance. A peak power efficiency of 79.87% is theoretically obtained in series mode on a top-quality German Intercity Express track (Track 270) at a vehicle speed of 160 mile/h (~257 km/h).

关键词: railway vehicle     primary damper     power regeneration     ride comfort     running safety    

Stability and agility: biped running over varied and unknown terrain

Yang YI,Zhi-yun LIN

《信息与电子工程前沿(英文)》 2015年 第16卷 第4期   页码 283-292 doi: 10.1631/FITEE.1400284

摘要: We tackle the problem of a biped running over varied and unknown terrain. Running is a necessary skill for a biped moving fast, but it increases the challenge of dynamic balance, especially when a biped is running on varied terrain without terrain information (due to the difficulty and cost of obtaining the terrain information in a timely manner). To address this issue, a new dynamic indicator called the sustainable running criterion is developed. The main idea is to sustain a running motion without falling by maintaining the system states within a running-feasible set, instead of running on a periodic limit cycle gait in the traditional way. To meet the precondition of the criterion, the angular moment about the center of gravity (COG) is restrained close to zero at the end of the stance phase. Then to ensure a small state jump at touchdown on the unknown terrain, the velocity of the swing foot is restrained within a specific range at the end of the flight phase. Finally, the position and velocity of the COG are driven into the running-feasible set. A five-link biped with underactuated point foot is considered in simulations. It is able to run over upward and downward terrain with a height difference of 0.15 m, which shows the effectiveness of our control scheme.

关键词: Underactuated running biped     Dynamic balance     Varied and unknown terrain    

破纪录的黑科技跑鞋

Chris Palmer

《工程(英文)》 2020年 第6卷 第9期   页码 962-963 doi: 10.1016/j.eng.2020.07.006

Machine learning for detecting mesial temporal lobe epilepsy by structural and functional neuroimaging

Baiwan Zhou, Dongmei An, Fenglai Xiao, Running Niu, Wenbin Li, Wei Li, Xin Tong, Graham J Kemp, Dong

《医学前沿(英文)》 2020年 第14卷 第5期   页码 630-641 doi: 10.1007/s11684-019-0718-4

摘要: Mesial temporal lobe epilepsy (mTLE), the most common type of focal epilepsy, is associated with functional and structural brain alterations. Machine learning (ML) techniques have been successfully used in discriminating mTLE from healthy controls. However, either functional or structural neuroimaging data are mostly used separately as input, and the opportunity to combine both has not been exploited yet. We conducted a multimodal ML study based on functional and structural neuroimaging measures. We enrolled 37 patients with left mTLE, 37 patients with right mTLE, and 74 healthy controls and trained a support vector ML model to distinguish them by using each measure and the combinations of the measures. For each single measure, we obtained a mean accuracy of 74% and 69% for discriminating left mTLE and right mTLE from controls, respectively, and 64% when all patients were combined. We achieved an accuracy of 78% by integrating functional data and 79% by integrating structural data for left mTLE, and the highest accuracy of 84% was obtained when all functional and structural measures were combined. These findings suggest that combining multimodal measures within a single model is a promising direction for improving the classification of individual patients with mTLE.

关键词: mesial temporal lobe epilepsy     functional magnetic resonance imaging     structural magnetic resonance imaging     machine learning     support vector machine    

Urban design based on public safety-Discussion on safety-based urban design

Kaizhen CAI, Jianguo WANG

《结构与土木工程前沿(英文)》 2009年 第3卷 第2期   页码 219-227 doi: 10.1007/s11709-009-0023-4

摘要: Because of public safety problems in construction of urban surroundings, this paper expounds the necessity of the study on public safety-based urban design in perspective of modern city. It brings forward the concept of safety-based urban design and attempts to explore the basic connotation and contents with framework for studies.

关键词: urban public safety     urban design     safety-based urban design    

中国食品安全科技发展方向讨论

魏益民,吴永宁,周乃元,潘家荣

《中国工程科学》 2005年 第7卷 第11期   页码 1-4

摘要:

从发展国家食品安全战略,强化国家食品安全科技的角度,提出中国食品安全科技优先发展的四大方向,即风险分析是食品安全科技战略的首选领域;“从农田到餐桌”整体控制体系是食品安全全程控制技术和操作规范的理论基础,是实施食品安全管理的重要技术手段;检测监测技术是预警、预防、应急的技术依据,应集中力量开发一批内控和标准检验必须的快速检测技术和标准检测技术;以政府、生产者、消费者为责任人主体的管理理念是食品安全管理的基本原则,食品链上的所有责任人应在保障食品质量和安全的问题上主动承担责任。

关键词: 食品安全     科技     战略     发展方向    

Probabilistic safety assessment of self-centering steel braced frame

Navid RAHGOZAR, Nima RAHGOZAR, Abdolreza S. MOGHADAM

《结构与土木工程前沿(英文)》 2018年 第12卷 第1期   页码 163-182 doi: 10.1007/s11709-017-0384-z

摘要: The main drawback of conventional braced frames is implicitly accepting structural damage under the design earthquake load, which leads to considerable economic losses. Controlled rocking self-centering system as a modern low-damage system is capable of minimizing the drawbacks of conventional braced frames. This paper quantifies main limit states and investigates the seismic performance of self-centering braced frame using a Probabilistic Safety Assessment procedure. Margin of safety, confidence level, and mean annual frequency of the self-centering archetypes for their main limit states, including PT yield, fuse fracture, and global collapse, are established and are compared with their acceptance criteria. Considering incorporating aleatory and epistemic uncertainties, the efficiency of the system is examined. Results of the investigation indicate that the design of low- and mid-rise self-centering archetypes could provide the adequate margin of safety against exceeding the undesirable limit-states.

关键词: self-centering steel braced frame     mean annual frequency     safety assessment     confidence level     margin of safety    

安全科学若干基础问题研究

吕保和

《中国工程科学》 2006年 第8卷 第11期   页码 57-61

摘要:

分析了安全的科学含义,引入了"灾事"的概念,指出安全科学的研究对象就是灾事,并进一步探讨了灾事的类型以及各类灾事之间的关系。阐述了构建安全科学的必要性和可行性,并从一个新的角度分析了安全科学的内涵以及构建安全科学的基本思路,论述了安全科学技术体系的层次结构。

关键词: 安全     灾事     安全科学     学科建设    

State of Practice of Construction Site Safety in the USA

Fei Dai,Yoojung Yoon,Hota V. GangaRao

《工程管理前沿(英文)》 2016年 第3卷 第3期   页码 275-282 doi: 10.15302/J-FEM-2016035

摘要: The construction industry has long been plagued with a high number of fatalities in the USA. Much safety improvements have been made after the USA Congress passed the Occupational Safety and Health Act in 1970. However, this industry still suffers from a disproportionately high rate of work-related fatalities in comparison to other industries. To provide a holistic view of current construction safety practices and corresponding performance, this paper reviews statistics of construction fatalities and their causes. It then presents efforts led to prevent work-related accidents and injuries by the federal safety agencies and the industry. Additionally, advantages and limitations of current practices in terms of construction safety have been discussed along with promotion of aspects in construction work environment.

关键词: workplace safety     construction industry     safety strategy     accident prevention     review work    

Analyzing construction safety through time series methods

Houchen CAO, Yang Miang GOH

《工程管理前沿(英文)》 2019年 第6卷 第2期   页码 262-274 doi: 10.1007/s42524-019-0015-6

摘要: The construction industry produces a large amount of data on a daily basis. However, existing data sets have not been fully exploited in analyzing the safety factors of construction projects. Thus, this work describes how temporal analysis techniques can be applied to improve the safety management of construction data. Various time series (TS) methods were adopted for identifying the leading indicators or predictors of construction accidents. The data set used herein was obtained from a large construction company that is based in Singapore and contains safety inspection scores, accident cases, and project-related data collected from 2008 to 2015. Five projects with complete and sufficient data for temporal analysis were selected from the data set. The filtered data set contained 23 potential leading indicators (predictors or input variables) of accidents (output or dependent variable). TS analyses were used to identify suitable accident predictors for each of the five projects. Subsequently, the selected input variables were used to develop three different TS models for predicting accident occurrences, and the vector error correction model was found to be the best model. It had the lowest root mean squared error value for three of the five projects analyzed. This study provides insights into how construction companies can utilize TS data analysis to identify projects with high risk of accidents.

关键词: time series     temporal     construction safety     leading indicators     accident prevention     forecasting    

Improvement of part-load performance of gas turbine by adjusting compressor inlet air temperature and IGV opening

《能源前沿(英文)》 2022年 第16卷 第6期   页码 1000-1016 doi: 10.1007/s11708-021-0746-z

摘要: A novel adjusting method for improving gas turbine (GT) efficiency and surge margin (SM) under part-load conditions is proposed. This method adopts the inlet air heating technology, which uses the waste heat of low-grade heat source and the inlet guide vane (IGV) opening adjustment. Moreover, the regulation rules of the compressor inlet air temperature and the IGV opening are studied comprehensively to optimize GT performance. A model and calculation method for an equilibrium running line is adopted based on the characteristic curves of the compressor and turbine. The equilibrium running lines calculated through the calculation method involve three part-load conditions and three IGV openings with different inlet air temperatures. The results show that there is an optimal matching relationship between IGV opening and inlet air temperature. For the best GT performance of a given load, the IGV could be adjusted according to inlet air temperature. In addition, inlet air heating has a considerable potential for the improvement of part-load performance of GT due to the increase in compressor efficiency, combustion efficiency, and turbine efficiency as well as turbine inlet temperature, when inlet air temperature is lower than the optimal value with different IGV openings. Further, when the IGV is in a full opening state and an optimal inlet air temperature is achieved by using the inlet air heating technology, GT efficiency and SM can be obviously higher than other IGV openings. The IGV can be left unadjusted, even when the load is as low as 50%. These findings indicate that inlet air heating has a great potential to replace the IGV to regulate load because GT efficiency and SM can be remarkably improved, which is different from the traditional viewpoints.

关键词: inlet air temperature     inlet guide vane (IGV) opening     part-load     equilibrium running line     gas turbine (GT) efficiency     surge margin (SM)    

Global challenges of food safety for China

Joseph J. JEN

《农业科学与工程前沿(英文)》 2018年 第5卷 第3期   页码 291-293 doi: 10.15302/J-FASE-2017167

摘要:

Ever since the Melamine event, China has faced challenges of food safety both domestically and globally. With the economic development, the Chinese consumers are demanding high quality, nutritious, and safe foods from the food industry but are not willing to pay higher prices. The Chinese food chain system of mostly small and medium enterprises presents challenges to the government to monitor and implement food safety laws and regulations. The academia and media are learning to take on their responsibilities with some success. Discussions and potential solutions of the global challenges of the five pillars for the food safety in China are presented here.

关键词: food safety     challenges     food industry     government     academia     media     consumer    

标题 作者 时间 类型 操作

Analysis on running safety of train on the bridge considering sudden change of wind load caused by wind

Tian ZHANG, He XIA, Weiwei GUO

期刊论文

Dynamic response of a long span suspension bridge and running safety of a train under wind action

GUO Weiwei, XIA He, XU You-lin

期刊论文

Evaluation of power regeneration in primary suspension for a railway vehicle

Ruichen WANG, Zhiwei WANG

期刊论文

Stability and agility: biped running over varied and unknown terrain

Yang YI,Zhi-yun LIN

期刊论文

破纪录的黑科技跑鞋

Chris Palmer

期刊论文

Machine learning for detecting mesial temporal lobe epilepsy by structural and functional neuroimaging

Baiwan Zhou, Dongmei An, Fenglai Xiao, Running Niu, Wenbin Li, Wei Li, Xin Tong, Graham J Kemp, Dong

期刊论文

办好《中国工程科学》为促进我国工程科技的发展和培养人才服务——《中国工程科学》编委会会议侧记

丁朝模

期刊论文

Urban design based on public safety-Discussion on safety-based urban design

Kaizhen CAI, Jianguo WANG

期刊论文

中国食品安全科技发展方向讨论

魏益民,吴永宁,周乃元,潘家荣

期刊论文

Probabilistic safety assessment of self-centering steel braced frame

Navid RAHGOZAR, Nima RAHGOZAR, Abdolreza S. MOGHADAM

期刊论文

安全科学若干基础问题研究

吕保和

期刊论文

State of Practice of Construction Site Safety in the USA

Fei Dai,Yoojung Yoon,Hota V. GangaRao

期刊论文

Analyzing construction safety through time series methods

Houchen CAO, Yang Miang GOH

期刊论文

Improvement of part-load performance of gas turbine by adjusting compressor inlet air temperature and IGV opening

期刊论文

Global challenges of food safety for China

Joseph J. JEN

期刊论文