检索结果-南通市图书馆

Small-scale fire tests in the underwater tunnel section model with new sidewall smoke extraction

在线全文

学校读者我要写书评

暂无评论

Deep Underground Science and Engineering 2024年第2期3卷 247-254页

作者： Shunyu Yue Ruifeng Miao Huihang Cheng Maohua Zhong Xiujun Yang Department of Engineering Physics Institute of Public Safety ResearchTsinghua UniversityBeijingChina Shanxi Province expressway Group Limited Liability Company Shanxi expressway Group Shuoshen Co. LtdShuozhouChina research institute of Highway Ministry of Transport RIOH Transport ConsultantsLtdBeijingChina

The Shenzhen–Zhongshan Bridge is a 24‐km‐long bridge and tunnel system,including a 6.8-km-long super cross section subsea *** solve the smoke exhaust problem of a super large cross-section subsea tunnel,the tunnel has a new smoke exhaust system that combines a horizontal smoke exhaust cross section at the top and sidewall smoke exhaust *** order to evaluate the potential fire hazards of this type of tunnel,a 1:30 tunnel model was established and 140 smallscale experiments on underwater tunnel fires were *** changing the fire power,fire location,and fan operation mode,different scenarios of submarine immersed tunnel fire were simulated and the related key parameters such as fire smoke diffusion behavior and smoke temperature distribution were *** this basis,the optimal smoke control strategy was proposed for different fire *** research results indicate that the new smoke exhaust system can fully utilize the smoke flow characteristics,significantly improve smoke exhaust efficiency,and increase available evacuation time,thus further enhancing the fire safety of super large cross-section subsea tunnels.

关键词： sidewall smoke extraction system small‐scale fire tests smoke control

Bending Failure Mode and Prediction Method of the Compressive Strain Capacity of A Submarine Pipeline with Dent Defects

在线全文

学校读者我要写书评

暂无评论

China Ocean Engineering 2024年第4期38卷 636-647页

作者： HOU Fu-heng JIA Lu-sheng CHEN Yan-fei ZHANG Qi ZHONG Rong-feng WANG Chun-sha School of Mechanical and transportation Engineering China University of PetroleumBeijingBeijing 102249China CNOOC research institute Ltd.Beijing 100028 China

A dent is a common type of defects for submarine *** submarine pipelines,high hydrostatic pressure and internal pressure are the main *** pipelines bend due to complex subsea conditions,the compression strain capacity may be *** into the local buckling failure and accurate prediction of the compressive strain capacity are important.A finite element model of a pipeline with a dent is *** buckling failure under a bending moment is investigated,and the compressive strain capacity is *** effects of different parameters on pipeline local buckling are *** results show that the dent depth,external pressure and internal pressure lead to different local buckling failure modes of the pipeline.A higher internal pressure indicates a larger compressive strain capacity,and the opposite is true for external *** the ratio of external pressure to collapse pressure of intact pipeline is greater than 0.1,the deeper the dent,the greater the compressive strain capacity of the *** as the ratio is less than 0.1,the opposite is *** the basis of these results,a regression equation for predicting the compressive strain capacity of a dented submarine pipeline is proposed,which can be referred to during the integrity assessment of a submarine pipeline.

关键词： submarine pipeline dent defect bending load local buckling compressive strain capacity

Intelligent fault diagnosis methods toward gas turbine: A review

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2024年第4期37卷 93-120页

作者： Xiaofeng LIU Yingjie CHEN Liuqi XIONG Jianhua WANG Chenshuang LUO Liming ZHANG Kehuan WANG School of transportation Science and Engineering Beihang UniversityBeijing 100191China Systems Engineering research institute China State Shipbuilding CorporationBeijing 100094China

Fault diagnosis plays a significant role in conducting condition-based maintenance and health management for gas turbines(GTs) to improve reliability and reduce costs. Various diagnosis methods developed by modeling engine systems or certain components implement faults detection and diagnosis based on the measurement of systemic parameters deviations. However, these conventional model-based methods are hindered by limitations of inability to handle the nonlinear nature, measurement uncertainty, fault coupling and other implementing problems. Recently, the development of artificial intelligence algorithms has provided an effective solution to the above problems, triggering broad researches for data-driven fault diagnosis methods with better accuracy,dynamic performance, and universality. This paper presents a systematic review of recently proposed intelligent fault diagnosis methods for GT engines, according to the classification of shallow learning methods, deep learning methods and hybrid intelligent methods. Moreover, the principle of typical algorithms, the evolution of enhanced methods, and the assessment of pros and cons are summarized to conclude the present status and look forward to the future in the field of GT fault diagnosis. Possible directions for development in method validation, information fusion, and interpretability of intelligent diagnosis methods are concluded in the end to provide insightful concepts for scholars in related fields.

关键词： Fault diagnosis Health management Gas turbine Artificial intelligence Intelligent diagnosis method

A Combination Prediction Model for Short Term Travel Demand of Urban Taxi

在线全文

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2024年第6期79卷 3877-3896页

作者： Mingyuan Li Yuanli Gu Qingqiao Geng Hongru Yu School of Traffic and transportation Beijing Jiaotong UniversityBeijing100044China Transport Planning and research institute Ministry of TransportBeijing100028China

This study proposes a prediction model considering external weather and holiday factors to address the issue of accurately predicting urban taxi travel demand caused by complex data and numerous influencing *** model integrates the Complete Ensemble Empirical Mode Decomposition with Adaptive Noise(CEEMDAN)and Convolutional Long Short Term Memory Neural Network(ConvLSTM)to predict short-term taxi travel *** CEEMDAN decomposition method effectively decomposes time series data into a set of modal components,capturing sequence characteristics at different time scales and *** on the sample entropy value of components,secondary processing of more complex sequence components after decomposition is employed to reduce the cumulative prediction error of component sequences and improve prediction *** this basis,considering the correlation between the spatiotemporal trends of short-term taxi traffic,a ConvLSTM neural network model with Long Short Term Memory(LSTM)time series processing ability and Convolutional Neural Networks(CNN)spatial feature processing ability is constructed to predict the travel demand for urban *** combined prediction model is tested on a taxi travel demand dataset in a certain area of *** results show that the CEEMDAN-ConvLSTM prediction model outperforms the LSTM,Autoregressive Integrated Moving Average model(ARIMA),CNN,and ConvLSTM benchmark models in terms of Symmetric Mean Absolute Percentage Error(SMAPE),Root Mean Square Error(RMSE),Mean Absolute Error(MAE),and R2 ***,the SMAPE metric exhibits a remarkable decline of 21.03%with the utilization of our proposed *** results confirm that our study provides a highly accurate and valid model for taxi travel demand forecasting.

关键词： Urban transport taxi travel demand prediction CEEMDAN-ConvLSTM modal components

Effects of Atmospheric Pressure on Developmental Characteristics and the Stability of Air Entraining Agent for Concrete

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Wuhan University of Technology(Materials Science) 2024年第4期39卷 979-989页

作者：李立辉牛开民 TIAN Bo CHEN Xin FU Ziqian ZHU Xuwei School of Civil Engineering Chongqing Jiaotong UniversityChongqing 400074China transportation Science and Engineering Harbin Institute of TechnologyHarbin 150090China research institute of Highway Ministry of TransportBeijing 100088China

In order to ascertain the effects of atmospheric pressure on developmental characteristics and the stability of AEA(air-entraining agent)solution bubbles,AEA solution experiments and AEA solution bubble experiments were,respectively,conducted in Peking(50 m,101.2 kPa)and Lhasa(3,650 m,63.1 kPa).Surface tensions and inflection-point concentrations were tested based on AEA solutions,whilst developmental characteristics,thicknesses and elastic coefficients of liquid films were tested based on air bubbles of AEA *** study involved three types of AEAs,which were TM-O,226A,and *** experimental results show that initial sizes of TM-O,226A,and 226S are,respectively,increased by 43.5%,17.5%,and 3.8%.With the decrease of ambient pressure,the drainage rate and the drainage index of AEA solution bubbles *** experiments show that the liquid film thicknesses of all tested AEA solution bubbles are in micron *** the atmospheric pressure decreases from 101.2 to 63.1 kPa,the liquid film thicknesses of three types of AEA solutions decrease in various degrees;and film elasticities at critical thicknesses *** film of 226S solution bubbles is the most stable,presenting as a minimum thickness *** should be noted that elastic coefficient of liquid film only represents the level at critical thickness,thus it can not be applied as the only evaluating indicator of bubble *** a type of AEA,factors affecting the stability of its bubbles under low atmospheric pressure include initial bubbles size,liquid film thickness,liquid film elasticity,ambient temperature,etc.

关键词： air-entraining agent surface tension bubble size liquid film thickness liquid film elasticity atmospheric pressure

Literature Review of Driving Fatigue research based on Bibliometric Analysis

在线全文

学校读者我要写书评

暂无评论

Journal of Traffic and transportation Engineering(English Edition) 2024年

作者： Fengxiang Guo Yiwen Zhou Xiao'an Wang Jing Cai Faculty of transportation Engineering， Kunming University of Science and Technology Yunnan transportation Science research institute Co.， Ltd.

Driving for a long time can lead to fatigue， which can affect information processing and decision-making， potentially threatening driving safety. By exploring the generation and variation patterns of driving fatigue and clarifying the application status of its detection and warning technology， traffic safety can be improved. In order to understand the research progress of driving fatigue， based on the Web of Science core database， this paper obtained 2127 English literature published from 1998 to 2023 (as of May 12， 2023)， covering a total of 5963 authors and 6019 keywords， and the bibliometric tool VOSviewer and R-Bibliometrix are used to analyze the literatures. Firstly， the literature statistical analysis is carried out from annual distribution， country distribution， source journals， and core authors. Secondly， the research hotspots and trends are analyzed from keywords co-occurrence， high-impact literature， theme evolution， and development trends. Finally， the development trend of driving fatigue research is discussed. The result shows that the hotspots in the field of driving fatigue include driving fatigue detection， fatigue driving risk and fatigue research of professional drivers， driver alertness and coping strategies for driver fatigue， and driver fatigue under automatic driving. And the improvement of the accuracy and reliability of driving fatigue detection will be the difficult point to break through in the future. It is necessary to build a multi-disciplinary and meticulously quantified driving fatigue and its risk assessment system， and strengthen the control of fatigue risks. research on intervention measures and education training for professional drivers needs to be deepened， while exploring the acceptance and compliance of intervention measures. Moreover， the evolution law and prevention strategies of driver fatigue under automatic conditions should be the focus of future research.

关键词：

research on the stability of virtual coupling train formation based on a PID controller under the influence of time delay

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

transportation Safety and Environment 2024年第3期6卷 133-139页

作者： Sixuan Qiu Ningzhou Li Xiaojuan Wei Gaosong Li School of Railway transportation Shanghai Institute of TechnologyShanghai 201418China

As the latest research direction of train-to-train communication,virtual coupling train formation technology has attracted the attention of many *** paper studies the influence of time delay on the formation of virtual coupled *** proposed a distributed PID controller,which means that trains can still form a stable fleet operation under the influence of communication delay and control *** modelling and analysis,the research uses Matlab to conduct simulation,involving two sets of *** including speed,acceleration,position,position error,expected distance between adjacent trains and actual distance between adjacent trains are *** results demonstrate that the distributed PID controller can effectively control the impact of time delay on the virtual coupling fleet.

关键词： virtual coupling train-to-train communication time delay PID controller

Analytical model for predicting folding stable state of bistable deployable composite boom

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2024年第8期37卷 460-469页

作者： Tianwei LIU Jiangbo BAI Nicholas FANTUZZI School of transportation Science and Engineering Beihang UniversityBeijing 100191China Jingdezhen research institute of Beihang University Jingdezhen 333000China DICAM Department University of BolognaBologna 40136Italy

Bistable Deployable Composite Boom(Bi-DCB)can achieve bistable function by storing and releasing strain energy,which has a good application prospect in space *** example,it serves as the main support section of deployable structures(e.g.,solar arrays and antennas).This paper investigates folding stable state of Bi-DCB through the analytical *** on Archimedes’helix and energy principle,an analytical model for predicting folding stable state of Bi-DCB was *** failure index of Bi-DCB in folding stable state were analyzed using the Tsai-Hill criterion and the maximum stress ***,a 2400 mm long Bi-DCB was fabricated using autoclave *** prediction results of the proposed model were compared with experiments and results of two other analytical *** is shown that the proposed model shows good prediction ***,the effect of geometric parameters on folding stable state of Bi-DCB was further investigated with the aid of the proposed model.

关键词： Bistable Deployable composite boom Solar arrays Antennas Archimedes’helix Folding Failure analysis

An Optimization Approach of IoD Deployment for Optimal Coverage Based on Radio Frequency Model

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computer Modeling in Engineering & Sciences 2024年第6期139卷 2627-2647页

作者： Tarek Sheltami Gamil Ahmed Ansar Yasar Computer Engineering Department Interdisciplinary Research Center of Smart Mobility and LogisticsKing Fahd University of Petroleum and MineralsDhahran31261Saudi Arabia transportation research institute(IMOB) Hasselt UniversityHasselt3500Belgium

Recently,Internet of Drones(IoD)has garnered significant attention due to its widespread ***,deploying IoD for area coverage poses numerous limitations and *** include interference between neighboring drones,the need for directional antennas,and altitude restrictions for *** challenges necessitate the development of efficient *** research paper presents a cooperative decision-making approach for an efficient IoDdeployment to address these challenges *** primary objective of this study is to achieve an efficient IoDdeployment strategy thatmaximizes the coverage regionwhile minimizing interference between neighboring *** deployment problem,the interference increases as the number of deployed drones increases,resulting in bad quality of *** the other hand,deploying a few drones cannot satisfy the coverage *** accomplish this,an enhanced version of a concise population-based meta-heuristic algorithm,namely Improved Particle SwarmOptimization(IPSO),is *** objective function of IPSO is defined based on the coverage probability,which is primarily influenced by the characteristics of the antennas and drone altitude.A radio frequency(RF)model is derived to evaluate the coverage quality,considering both Line of Sight(LOS)and Non-Line of Sight(NLOS)down-link coverage probabilities for ground *** is assumed that each drone is equipped with a directional antenna to optimize coverage in a given *** simulations are conducted to assess the effectiveness of the proposed *** demonstrate that the proposed method achieves maximum coverage with minimum transmission ***,a comparison is made against Collaborative Visual Area Coverage Approach(CVACA),and a game-based approach in terms of coverage quality and convergence *** simulation results reveal that our approach outperforms both CVACA and the gamebased schemes in terms of coverage an

关键词： IoD line of sight optimal deployment IPSO RF model