检索结果-内蒙古大学图书馆

Adjustable tongue vane for improving the energy performance of a submersible single-channel pump for wastewater treatment

引用

Heliyon 2025年第1期11卷 e41511页

作者： Nguyen, duc-Anh Wu, Kexin Li, Xiaojun Kim, Gyeong Sung Kim, Jin-Hyuk Convergence Manufacturing System Engineering (Green Process and Energy System Engineering) University of Science & Technology Daejeon 34113 South Korea Carbon Neutral Technology R&D Department Korea Institute of Industrial Technology Cheonan 31056 South Korea National-Provincial Joint Engineering Laboratory for Fluid Transmission System Technology Zhejiang Sci-Tech University Hangzhou 310018 China Department of Physics and Engineering California State University Bakersfield Bakersfield 93311 CA United States

Single-channel pump is a type of centrifugal pump that is frequently utilized for wastewater treatment around the world, but they often operate at low flow rates with low efficiency and loud noise because the wastewater contains many impurities. In this study, an adjustable tongue vane was developed that controls the internal flow direction in the volute to increase the energy performance of a single-channel pump. Numerical simulations were conducted by using reynolds-averaged Navier-Stokes equations and shear stress transport turbulence model to evaluate the energy loss inside the volute. In the experiment, the single-channel pump demonstrated stable operation in the waste environment. In the numerical simulation, the −10° model increased the efficiency and total head by 1.007 % and 1.242 %, respectively compared to the reference model at the best efficiency point. At low flow rates, however, the −20° model increased the efficiency and total head by up to 25.126 % and 5.604 %, respectively, while decreasing the power consumption by up to 15.533 % compared to the reference model. This improvement is attributed to the adjustable tongue vane suppressing separation flow, which reduces hydraulic losses and energy dissipation. The proposed tongue vane can be used to improve the energy performance of not only single-channel pumps but also other centrifugal turbomachinery. © 2025 The Authors

关键词： Energy performance Entropy generation Single-channel pump Tongue vane

来源：评论

学校读者我要写书评

暂无评论

Hydrate reformation Characteristics in Offshore Natural Gas Hydrate reservoir Using the Horizontal Well depressurization Production

Hydrate Reformation Characteristics in Offshore Natural Gas ...

引用

Offshore Technology Conference, OTC 2025

作者： Zhang, Jianbo Liu, Xiaoao Luo, Jiazheng Sun, Xiaohui Zhong, Jie Wang, Zhiyuan Huang, Weian Sun, Baojiang Wang, Xiao School of Petroleum Engineering China University of Petroleum East China Shandong Qingdao China Shandong Key Laboratory of Offshore Oil & Gas and Hydrates Development Shandong Qingdao China CNPC Engineering Technology R&D Company Limited Beijing China No.7 Oil Production Plant PetroChina Changqing Oilfield Company Shanxi Xian China College of Computer Science and Technology China University of Petroleum East China Qingdao China School of Materials Science and Engineering China University of Petroleum East China Qingdao China

ISBN: (纸本)9781959025610

during depressurization production of natural gas hydrate, the reformation of hydrate is likely to occur in the reservoir, hindering the efficient development of hydrate. Previous studies on the reformation of hydrate in the process of natural gas hydrate production were mainly focused on experimental research and numerical simulation under experimental conditions. In this work, a multi-field coupling flow model considering the effect of hydrate reformation during depressurization production of hydrate reservoir was established, and the accuracy of the model was verified by the field measured data. Meanwhile, the reformation characteristics of hydrate in the reservoir using the horizontal well depressurization production were simulated and investigated. The results show that the reformation of hydrate in the reservoir mainly occurs in the upper part and middle boundary of the hydrate decomposition zone during the depressurization production. Moreover, the smaller the pressure drop extent, absolute permeability and initial hydrate saturation, and the deeper the horizontal well, the larger the hydrate secondary formation zone in the reservoir, the faster the rate of hydrate reformation, and the greater the hydrate saturation caused by hydrate reformation would be, which would make the risk of flow blockage by reformed hydrate in the reservoir rise. The results of this study can provide theoretical support for the safe and efficient development of offshore natural gas hydrate. © 2025, Offshore Technology Conference.

关键词： Offshore gas well production

来源：评论

学校读者我要写书评

暂无评论

PMS-sharing: Framework for automatically authenticating users in a group to allow sharing storage 5

PMS-sharing: Framework for automatically authenticating user...

引用

5th International Conference on Communication and Electronics systems, ICCES 2020

作者： Suthar, Nitesh Yadav, rajesh Kr. System R&D - Convergence Group Samsung Electronics Noida India Dept. of Computer Science & Engineering Delhi Technological University Delhi India

ISBN: (纸本)9781728153711

Cloud storage is a very famous buzz word nowadays. There are many cloud storage service providers in the market and millions of mobile users are accessing cloud storage to store and access various personal data such as photos, videos and documents. In this era of smart mobile devices, every user is having devices with various storage capacity i.e. 8, 16, 32, 64, 128 GB and even more storage is going to be embedded in next generation of devices. These storage are widely used for storing and sharing data among multiple people. In this paper, a model and framework is proposed to automatically authenticate users within a group to allow sharing data while connected to same wireless network where initial group is formed by user (group owner) to allow set of users to access shared contents thereafter users in a group are automatically authenticated. The proposed solution is calledpersonal mobile storage sharing (PMS-Sharing). The application and framework is developed and tested on android mobile phones supporting Android version 4.4 and above. © 2020 IEEE.

关键词： Cloud storage

来源：评论

学校读者我要写书评

暂无评论

Grid-forming Control of VSC-HVdC systems Connecting Asynchronous Power Grids

Grid-forming Control of VSC-HVDC Systems Connecting Asynchro...

引用

Power system and Green Energy Conference (PSGEC)

作者： Mingqun Liu Guanming Zeng Xin He Liang Tu Peng He Yihua Zhu Electric Power Research Institute Yunnan Power Grid Co. Ltd. Kunming State Key Laboratory of HVDC Electric Power Research Institute China Southern Power Grid National Energy Power Grid Technology R&D Centre Guangzhou China Guangdong Provincial Key Laboratory of Intelligent Operation and Control for New Energy Power System CSG Key Laboratory for Power System Simulation Electric Power Research Institute China Southern Power Grid Guangzhou China State Key Laboratory of HVDC Electric Power Research Institute China Southern Power Grid CSG Key Laboratory for Power System Simulation Electric Power Research Institute China Southern Power Grid Guangzhou China

ISBN: (数字)9798350365573

ISBN: (纸本)9798350365580

Interconnecting asynchronous power grids with the VSC-HVdC transmission is an important trend. To enhance the weak grid operation performance and grid frequency response capability of the VSC-HVdC system, a novel grid-forming without using the phase-locked-loop is applied in both ends of the VSC-HVdC system. The dC voltage-Active power droop-based grid-synchronization method is utilized. With the proposed method, the sending and the receiving end MMCs perform like a synchronous motor and a synchronous generator, respectively. When the frequency changes in either grid, the system can automatically response to it and change the active power transmission by VSC-HVdC to achieve primary frequency regulation and active frequency support. Finally, the validity of the dual-end grid-forming control is verified based on the simulations in PSCAd/EMTdC.

关键词： Power transmission Control systems Synchronous motors Market research Power grids Synchronous generators Synchronization Phase locked loops Frequency control Grid forming

来源：评论

学校读者我要写书评

暂无评论

Comparison and Testing of Equivalent Modeling Methods for Wind Farm Composed of doubly-Fed Induction Generators

Comparison and Testing of Equivalent Modeling Methods for Wi...

引用

IEEE Conference on Energy Internet and Energy system Integration (EI2)

作者： Binjiang Hu Yihua Zhu Liang Tu Zun Ma Xian Meng Chao Xing State Key Laboratory of HVDC Electric Power Research Institute China Southern Power Grid Guangzhou China Guangdong Provincial Key Laboratory of Intelligent Operation and Control for New Energy Power System Guangzhou China National Energy Power Grid Technology R&D Centre Guangzhou China Electric Power Research Institute of Yunnan Power Grid Co. Ltd. Kunming China

ISBN: (数字)9798331523527

ISBN: (纸本)9798331523534

For analyzing the power system with high penetration of wind power, it is important to establish accurate models of wind turbines and wind farms, which is a basic and important work. In the analysis of wind power grid integration, it is necessary to aggregate the equivalent value of the wind farm into one or a few wind turbines. At present, there are two commonly used equivalence methods: current source multiplication (commonly used in commercial software) and full dynamic aggregation method. The former achieves wind farm equivalence by multiplying the output current of a single wind turbine generator, while the latter dynamically aggregates the wind farm into one or several large wind turbine generators. There is still a lack of research on the differences between the two. Based on the actual wind farm structure, this paper studies the electrical characteristics of steady-state operation and transient fault ride through operation using single machine dynamic aggregation method and current source multiplication method separately, and compares the equivalent simulation results with the detailed wind farm simulation results. The equivalent accuracy of the single machine aggregation method and the current source multiplication method is calculated to provide a reference for method selection in wind farm equivalent modeling.

关键词： reactive power Accuracy Simulation Power system dynamics doubly fed induction generators Wind farms Generators Wind turbines Impedance Transient analysis

来源：评论

学校读者我要写书评

暂无评论

Adaptive Identification of Power system Operational States Based on Spatio-Temporal dynamic Graph Neural Networks

Adaptive Identification of Power System Operational States B...

引用

Electronic Technology, Communication and Information (ICETCI), IEEE International Conference on

作者： Qingqing Zhang Qinfeng Ma Mingshun Liu Jie Zhang Yihua Zhu Zhuohang Liang Su An Qingxin Pu Jiang dai Power Dispatching and Control Center of Guizhou Power Grid Co. Ltd. Guizhou China State Key Laboratory of HVDC Electric Power Research Institute China Southern Power Grid Guangzhou China National Energy Power Grid Technology R&D Centre Guangzhou China Guangdong Provincial Key Laboratory of Intelligent Operation and Control for New Energy Power System Guangzhou China

ISBN: (数字)9798350361643

ISBN: (纸本)9798350361650

The state identification of the operational status of power systems plays a crucial role in ensuring the safety, efficiency, and reliable operation of power systems, forming the foundation for the management and control of power system operations. In the practical operation of power systems, the duration of fault states is short, while the system remains in a safe and stable state for a significantly longer period, leading to an imbalance in the training samples available. This imbalance can cause traditional machine learning classification algorithms to favor the majority categories of power system operational states, resulting in inaccurate evaluation metrics and reduced model generalization capability. To address this issue, this paper introduces a spatiotemporal dynamic graph neural network model for the identification of power system operational states. By incorporating class cost coefficients, focal loss, and cross-entropy in a joint loss function, the model adaptively focuses on the less represented operational state categories during training, improving classification accuracy on imbalanced and challenging samples. Moreover, the integration of temporal information and spatial topology information within the graph neural network enhances the model’s robustness and generalization ability in state identification. Experimental results on the standard IEEE 68-bus system demonstrate that, compared to traditional machine learning methods, the proposed joint loss with the spatiotemporal dynamic graph neural network model achieves higher accuracy in the identification of power system operational states, significantly improving classification performance on imbalanced samples with a 4.8% increase in F1-score, reaching a peak F1-score of 98.6%.

关键词： Training Adaptation models Accuracy Power system dynamics Power system stability Graph neural networks Stability analysis

来源：评论

学校读者我要写书评

暂无评论

Hard Sample Matters a Lot in Zero-Shot Quantization

arXiv

引用

arXiv 2023年

作者： Li, Huantong Wu, Xiangmiao Lv, Fanbing Liao, daihai Li, Thomas H. Zhang, Yonggang Han, Bo Tan, Mingkui South China University of Technology China Changsha Hisense Intelligent System Research Institute Co. Ltd China Hong Kong Baptist University Hong Kong Key Laboratory of Big Data and Intelligent Robot Ministry of Education China PengCheng Laboratory China Information Technology R&D Innovation Center of Peking University China School of Electronic and Computer Engineering Peking University Shenzhen Graduate School Shenzhen China

Zero-shot quantization (ZSQ) is promising for compressing and accelerating deep neural networks when the data for training full-precision models are inaccessible. In ZSQ, network quantization is performed using synthetic samples, thus, the performance of quantized models depends heavily on the quality of synthetic samples. Nonetheless, we find that the synthetic samples constructed in existing ZSQ methods can be easily fitted by models. Accordingly, quantized models obtained by these methods suffer from significant performance degradation on hard samples. To address this issue, we propose HArd sample Synthesizing and Training (HAST). Specifically, HAST pays more attention to hard samples when synthesizing samples and makes synthetic samples hard to fit when training quantized models. HAST aligns features extracted by full-precision and quantized models to ensure the similarity between features extracted by these two models. Extensive experiments show that HAST significantly outperforms existing ZSQ methods, achieving performance comparable to models that are quantized with real data. Copyright © 2023, The Authors. All rights reserved.

关键词： deep neural networks

来源：评论

学校读者我要写书评

暂无评论

Unified Grid-Forming Control for MMC-MTdC systems with renewable Power Integration

Unified Grid-Forming Control for MMC-MTDC Systems with Renew...

引用

HVdC (HVdC), International Conference on

作者： renxin Yang Haiqing Cai Mingzhang Su Haohan Gu Zhihao Chen Xu Cai Key Laboratory of Control of Power Transmission and Conversion Shanghai Jiao Tong University Shanghai China State Key Laboratory of HVDC Electric Power Research Institute China Southern Power Grid Guangzhou China National Energy Power Grid Technology R&D Centre China Southern Power Grid Guangzhou China Guangdong Provincial Key Laboratory of Intelligent Operation and Control for New Energy Power System China Southern Power Grid Guangzhou China

ISBN: (数字)9798350387759

ISBN: (纸本)9798350387766

Using modular multilevel converter-based multi-terminal high voltage direct current (MMC-MTdC) transmission to integrate large-scale renewable power into the main power grid is an important development trend in China. To cope with the stability issues under weak grid conditions, different grid-forming control strategies have been proposed for the MMC in MTdC transmission systems. These control strategies have different structures due to different control targets and are difficult to unify. To solve this problem, a novel grid-forming control structure is proposed in this paper. The MMC emulates the synchronous generator (SG), and the submodule capacitor voltage emulates the SG rotor speed. On this basis, by utilizing the modulation control degree freedom, a unified dC-side controller is proposed to realize different control targets. Finally, the simulation model of a 4-terminal MMC-MTdC transmission system with renewable power integration is established in the PSCAd/EMTdC. The effectiveness of the proposed strategy is verified by the simulation results.

关键词： renewable energy sources Simulation HVdC transmission Capacitors rotors Switches Control systems Synchronous generators Stability analysis Grid forming

来源：评论

学校读者我要写书评

暂无评论

A Novel Intelligent AI-Based Security to Enhance the data Communication: An Empirical review

A Novel Intelligent AI-Based Security to Enhance the Data Co...

引用

International Conference on Intelligent systems and Sustainable Computing, ICISSC 2022

作者： Shaik, Amjan Hung, Bui Thanh Chakrabarti, Prasun Siva Shankar, S. Parveen, Nikhat Department of Computer Science and Engineering Dean R&D St. Peter’s Engineering College Maisammaguda Telangana Hyderabad India Data Science Laboratory Faculty of Information Technology Industrial University of Ho Chi Minh Ho Chi Minh Viet Nam Department of Computer Science and Engineering Sir Padampat Singhania University Rajasthan Udaipur India Adjunct Distinguished Professor ITM SLS Baroda University Gujarat Vadodara India CSE K G Reddy College of Engineering and Technology Moinabad India CSE Koneru Lakshmaiah Education Foundation AP Guntur Vaddeswaram India

ISBN: (纸本)9789819947164

The transmission of digital data between two devices is termed data communication. As the world nowadays relies on digital communication, the transferring of data among various devices is vitally important, and hence, the security of the data is a concern. Several works are carried out to secure the data transmission between the devices in various applications like mobile communication, wireless communication, vehicular communication, and more. Incorporated with security, the data classification is also performed to ignore the unwanted or hackers’ data. In this work, we have discussed several secure data communication-related papers from various applications. Works including machine learning-based approaches such as decision tree, linear regression, logistic regression, KNN, K-means, and deep learning-based approaches such as a convolutional neural network, recurrent neural network, and long short-term memory approaches were discussed and listed with their limitations along with merits. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

关键词： decision trees

来源：评论

学校读者我要写书评

暂无评论

Impedance Network Modeling of GFL and GFM Converters system Considering AC/dC Couplings

Impedance Network Modeling of GFL and GFM Converters System ...

引用

IEEE International Conference on Power and Power and renewable Energy (ICPrE)

作者： Kun Zheng Chao Luo Zhiyuan Sun Yihua Zhu Jiawei Yu Guangxi Key Laboratory of Intelligent Control and Maintenance of Power Equipment Guangxi Power Grid Electric Power Research Institute China Southern Power Grid Nanning China State Key Laboratory of HVDC Electric Power Research Institute China Southern Power Grid National Energy Power Grid Technology R&D Centre Guangdong Provincial Key Laboratory of Intelligent Operation and Control for New Energy Power System Guang zhou China

ISBN: (数字)9798350377460

ISBN: (纸本)9798350377477

With the rapid development of grid-forming (GFM) control technology, integrating GFM control into grid-following (GFL) control-dominated systems has been attached with great importance due to the enhancement of grid supporting capability. To keep the normal operation of such GFL/GFM hybrid system, its small-signal stability needs to be studied, while the current research mainly focuses on the GFL/GFM converters' ac-side dynamics and usually ignore their ac/dc couplings. Therefore, this paper proposes an impedance network modeling method for GFL/GFM multi-converters system, and then a nodal admittance matrix retaining both ac and dc nodes is obtained. With such model, system marginal unstable condition can be accurately determined. Further, the influence of the capacity ratio between GFL and GFM converter is discussed. Simulation results of a typical GFL/GFM hybrid system verify the theoretical analysis.

关键词： Couplings renewable energy sources Grid following Simulation Power system stability Stability analysis Admittance Impedance Matrix converters Grid forming

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：