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Copyright of Journal of Engineering for Thermal Energy & Power / Reneng Dongli Gongcheng is the property of Journal of Engineering for Thermal Energy & Power 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 introduction of high-speed railway lines into hubs brings challenges to the design of signaling system. Combined with the introduction of Beijing-Shenyang Passenger Dedicated Railway into Beijing hub, this paper proposes optimization schemes from the aspects of the selection of train control level in the hub, automatic trigger at the liaison boundary between yards, and improving the overall operation efficiency of the hub, so as to serve as a reference for other similar projects. [ABSTRACT FROM AUTHOR]

The structural strength of the hub directly determines the overall structural safety of a wind turbine and the transmission of the wind turbine load， and the lighter the hubs are， the more efficient power generation can be. In order to study the influencing factors of strength and structural optimization of wind turbine hubs， the paper studies the hubs of a 2.5 MW wind turbine generating unit. First， it discusses the structural form and stress characteristics of the hub； then it designs four hub structure schemes with different typical characteristics and establishes a corresponding finite element analysis model； finally， the distribution laws of ultimate stress and fatigue damages of hubs in each of the design schemes are summarized. The strength characteristics and design principles of the hubs can provide a reference for design and structural optimization of the wind turbine hubs.

Copyright of South Architecture / Nanfang Jianzhu is the property of South Architecture 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.)

Copyright of Railway Signalling & Communication Engineering is the property of Railway Signalling & Communication Engineering 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.)

Copyright of Railway Signalling & Communication Engineering is the property of Railway Signalling & Communication Engineering 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.)

Copyright of Computer Measurement & Control is the property of Magazine Agency of Computer Measurement & Control 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.)

In this paper, we focus on the structure learning problem of the hub network. In the neighborhood selection framework, we use the L1 and L2 regularizers to incorporate the sparse and group prior of the hub network, so as to make the network easier to generate Hub. We employ the coordinate descent algorithm to solve the resulting model. Simulation and real data analysis show that the proposed method is effective and applicable in parameter estimation and model selection, and results illustrate the influence ability of the control parameter on the model.

The drag of coaxial helicopter hub accounts is more than 50% of the total helicopter's waste drag, so it is necessary to research the drag characteristics and reduction design of the hub. Wind tunnel test is carried out for a coaxial helicopter hub model, drag reduction scheme and drag reduction scheme with vortex generator. The drag characteristics of coaxial helicopter hub is researched. The drag reduction effect of the drag reduction scheme and drag reduction scheme with vortex generator are verified. The results show that the azimuth, rotation speed and attack angle have little influence on the drag of hub and its drag reduction scheme, the gap between the upper and lower hub fairings and the shaft fairing has a relatively large impact on drag, the drag reduction scheme can reduce the drag by about 33%, and the drag effect of the vortex generator is not obvious.

Copyright of Rare Metal Materials & Engineering is the property of Northwest Institute for Nonferrous Metal Research 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.)

In order to minimize the aerodynamic drag of coaxial rigid rotor hub，the airfoil cross-section vortex generator installed on the shaft fairing. The vortex generator installation programs with different expansion length，chord length，installation number and locations are designed，then calculate and analysis the drag characteristics of coaxial twin hub by the method of solving N -S equation. Finally，the surface pressure and spatial flow are analyzed. The results show that vortex generator can reduce about 5% of the drag of coaxial twin hub drag reduction program. The increment of chord length and the movement of vortex generator to lower hub is conducive to further reduce the drag. The research results can provide a reference for the application of vortex generator and the drag reduction design of rotor hub. [ABSTRACT FROM AUTHOR]

A full-scale wind tunnel tests have been conducted to investigate the rotor hub drag characteristics of a coaxial rigid rotor through a rotor hub test rigin China Aerodynamics Research and Development CenterFL- 14 wind tunnel. The test modelsare typical coaxial rigid rotor hub models，including the upper and lower hub fairing models and four intermediate shaft fairing models. There are four interchangeable mid-shaft fairings designed，i. e. ，three optimized fairings based on airfoil shape ，and a bare shaft for reference. Multiple fairing geometries are tested at different rotational speeds，wind velocity and different attitude angle in wind tunnel to obtain basic aerodynamic loads. The effect of blade stub on drag of rotor hub is also analyzed. Drag characteristics between three fairings and bare shaft are compared，and the influence law of coaxial rotors hub drag is obtained. The experimental results show that the best fairing configurationreduces the drag from a bare hub by 37%. [ABSTRACT FROM AUTHOR]

Aiming at the strength safety problem of MW wind turbine hub, the ultimate and fatigue strength of a certain high level wind turbine hub were analyzed, by method of combination of the global model rotor and the sub-model hub, and integration of critical plane method and maximum principal stress algorithm, using the finite element analysis software ANSYS and the fatigue analysis software FE-safe, with consideration of the nonlinear effects of pitch bearings. A pitch cushioning device was designed in the hub assembly system to stay the blade at feathering position, and the ultimate strengths of the pitch stop and the stop notch, components of the pitch cushioning device, under feathering conditions were analyzed. The results indicate that the ultimate and fatigue strength of the hub, and the ultimate strengths of the pitch stop and the stop notch can all meet the design requirements, which provide a certain reference for the design of the hub and the pitch cushioning device. [ABSTRACT FROM AUTHOR]

Copyright of Computer Measurement & Control is the property of Magazine Agency of Computer Measurement & Control 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.)

Chengdu has long been closely associated with the Silk Road. In ancient times, Chengdu was at the intersection of the Northern Silk Road, the Southern Silk Road and the Yangtze River Economic Belt. The three corridors were of great economic and transport significance. Under the reign of Emperor Wu of the Han Dynasty, the Northern Silk Road was developed and Chengdu became an important supplier of silk, a major product exported along the Northern Silk Road. In particular, Sichuan brocade, a high-end silk product transported via the Silk Road, was the specialty of Chengdu. Significant amounts of Sichuan brocade have been unearthed at key archaeological sites along the Silk Road, providing strong evidence of Chengdu’s important connection with the Silk Road. During the period of the Northern and Southern dynasties (420-581), the Hexi Corridor along the Silk Road was blocked by the war, resulting in the interruption of the Northern Silk Road from Chang’an (currently Xi’an). Under such circumstances, a new silk road came into being, which started in Chengdu and traversed the grasslands in northwestern Sichuan, Longnan in Gansu and Qinghai, to the Silk Road’s He Nan Section (Tuyuhun) in the Western Regions. This new Silk Road enabled uninterrupted trade and exchanges between the hinterland of China and regimes in northwestern China and many more kingdoms throughout Eurasia. Prior to the Qin and Han dynasties (221 BC-AD 220), the Southern Silk Road, also starting in Chengdu, had been developed, and was in service for over 2,000 years. It is a key corridor allowing the hinterland of China to conduct economic and cultural exchanges within regions now known as Yunnan and Myanmar, as well as other areas of Southeast Asia. As the political, economic and cultural center of the upper reaches of the Yangtze River, Chengdu had maintained close economic and cultural relationships with the middle and lower reaches of the Yangtze River from the pre-Qin period, and had been linked to the Maritime Silk Road via key cities along the Yangtze River. Since the Northern and Southern Dynasties, Chengdu has also been a center for external cultural exchanges and more importantly, a center for the popularization of Buddhist culture in the hinterland of China.

Aiming at the design problems of the bolt connection strength of hub and pitch-bearing of a MW wind turbine, the ANSYS software was utilized to establish the simulated model of this bolt connection. With the study of pitch-bearing force analysis and FEM modeling method of bearing and bolt, the strength analysis of this bolt connection and the contact surface slip verification were calculated by the FEM method and theoretical method respectively based on the GL specification. The results indicate that this bolt connection satisfies the design requirement and the two maximum bolt stresses are almost the same and the slip which transfers shear force do not occur on the contact surface between pitch-bearing and hub. The results can provide some references for the bolt connection of hub and pitch-bearing. [ABSTRACT FROM AUTHOR]