Dynamic Analysis of a Novel Rail-Grinding Car Using Open-Structured Abrasive Belt for High-Speed Railways

Nowadays, applying rail grinding has been worldwide recognized as the routine maintenance approach to improving the wheel-rail relationship, as well as extending the rail’s serving life. However, the traditional rail repair technology with the abrasive wheel or the milling cutter is getting harder to meet the increasing demand for high efficiency with high speed. In this paper, according to the engineering requirements and constraints, a new fast rail-grinding car based on open-structured belt grinding technology was designed for the corrugation treatment on high-speed railways. A corresponding simulation model was established and its dynamic working performance was then assessed by SIMPACK software. Results of the four dynamic indices for both straight and curve tracks were within the limits, which had verified the design rationality of the new rail-grinding car. Those dynamic indices are the lateral vibration acceleration, the vertical vibration acceleration, the axle transverse force, and the derailment coefficient.

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Rail Corrugation of High-Speed Railway Induced by Rail Grinding

Shock and Vibration ◽

10.1155/2021/5546809 ◽

2021 ◽

Vol 2021 ◽

pp. 1-14

Author(s):

Xing Du ◽

Xuesong Jin ◽

Guotang Zhao ◽

Zefeng Wen ◽

Wei Li

Keyword(s):

High Speed ◽

Field Tests ◽

Vertical Vibration ◽

Clear Correlation ◽

High Speed Rail ◽

Rail Corrugation ◽

Rail Grinding ◽

Initial Excitation ◽

Technical Operation ◽

Grinding Stone

Rail corrugation is a common railway defect that involves diverse and complex factors. Rail grinding is also the most commonly used method to address corrugations. Through numerous irregularity tests and one-third octave frequency spectrum analyses, this study determined the characteristics and development process for rail corrugation on high-speed rail tracks. The vibration transmission properties of the grinding train were tested using the force hammer impacting method. Thereafter, using a simulation, the influence of the vertical vibration behavior of the grinding stone and the stiffness of the hydraulics were determined. Through a series of field tests and numerical simulations, this study revealed a clear correlation between rail corrugation and rail grinding and confirmed that the technical operation of rail grinding is closely associated with regular grinding marks at a wavelength of approximately 60 mm on rail surfaces. The combination of the natural vibration of the grinding stone (frequency of 60 Hz) and an inappropriate operational process can aggravate the grinding marks on the rail surfaces, thereby forming an initial excitation of rail corrugation. Although a large number of irregularity tests are performed after rail grinding, these wavelength-fixing grinding marks can cause the formation and development of rail corrugation. Suggestions for improving the high-speed rail-grinding technology are also provided.

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Development and Key Technologies of High-Speed Grinding

Materials Science Forum ◽

10.4028/www.scientific.net/msf.723.445 ◽

2012 ◽

Vol 723 ◽

pp. 445-449 ◽

Cited By ~ 1

Author(s):

Yong Yu ◽

Pei Quan Guo ◽

Yan Ke Cao ◽

Xiao Wei Wang ◽

Pu Zhang

Keyword(s):

High Speed ◽

High Efficiency ◽

The Other ◽

Belt Grinding ◽

Spindle System ◽

Abrasive Belt ◽

Key Technologies ◽

High Speed Grinding

The mechanism and characteristic of high speed grinding and the technology and development of high speed grinding were introduced. High efficiency grinding including ultrahigh speed grinding, high efficiency deep grinding, creep deep grinding and abrasive belt grinding was analyzed. The technology about manufacturing the spindle system in super high speed grinding and the other main interrelated technology about grinding were also described.

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Application and Development of High-Efficiency Abrasive Finishing

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.189-193.3113 ◽

2011 ◽

Vol 189-193 ◽

pp. 3113-3116

Author(s):

Chang He Li ◽

Ling Yun Qi ◽

Hua Yang Zhao

Keyword(s):

High Speed ◽

High Performance ◽

High Efficiency ◽

Removal Rate ◽

Grinding Wheel ◽

Abrasive Machining ◽

Machining Processes ◽

Belt Grinding ◽

Hard And Brittle Materials ◽

High Removal Rate

High-efficiency abrasive machining is one of the important technology of advanced manufacture. Combined with raw and finishing machining, it can attain high removal rate like turning, milling and planning. The difficult-to-grinding materials can also be ground by means of this method with high performance. In the present paper, development status and latest progresses on high efficiency abrasive machining technologies relate to high speed and super-high speed grinding, high efficiency deep-cut grinding, hard and brittle materials high-efficiency grinding, powerful grinding and belt grinding were summarized. The efficiency and parameters range of these abrasive machining processes were compared. The key technologies of high efficiency abrasive machining, including grinding wheel, spindle and bearing, grinder, coolant supplying, installation and orientation of wheel and workpiece and safety defended, as well as intelligent monitor and NC grinding were investigated.

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One-step Separation and Purification of Four Phenolic Acids from Stenoloma chusanum (L.) Ching by Medium-pressure Liquid Chromatography and High-speed Counter-current Chromatography

The Natural Products Journal ◽

10.2174/2210315508666181004115422 ◽

2019 ◽

Vol 9 (2) ◽

pp. 138-143

Author(s):

Tianyun Li ◽

Xiling Dai ◽

Yichen Li ◽

Guozheng Huang ◽

Jianguo Cao

Keyword(s):

Natural Products ◽

Liquid Chromatography ◽

Phenolic Acids ◽

High Speed ◽

High Efficiency ◽

Total Phenolic ◽

Medium Pressure ◽

Medium Pressure Liquid Chromatography ◽

One Step ◽

Counter Current

Background:Stenoloma chusanum (L.) Ching is a Chinese traditional medicinal fern with high total flavonoid and total phenolic content. Traditionally, phenolic compounds were separated by using column chromatography, which is relatively inefficient. </P><P> Objective: This study aims to use an efficient method to separate natural products from S. chusanum by Medium-Pressure Liquid Chromatography (MPLC) and High-Speed Counter-Current Chromatography (HSCCC).Methods:In the present research, firstly, a sample (2.5 g) from the dichloromethane extract of S. chusanum was separated by MPLC. Next, fraction P5 was purified by HSCCC with a two-phase solvent system composed of hexane-ethyl acetate-methanol-water (HEMWat) at a volume ratio of 2:4:1:4 (v/v/v/v). </P><P> Result: Four phenolic acids were obtained and their structures were identified by means of NMR and ESI-mass analysis. They were identified as: 1) protocatechuic acid (34 mg, purity 90.1%), 2) syringic acid (66 mg, purity 99.0%), 3) p-hydroxybenzoic acid (5 mg, purity 91.2%) and 4) vanillic acid (6 mg, purity 99.3%).Conclusion:The combination of MPLC and HSCCC is a high-efficiency separation method for natural products. This is the first report with regard to the separation of four phenolic acids in one step by MPLC and HSCCC from S. chusanum (L.) Ching.

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On-chip trans-dimensional plasmonic router

Nanophotonics ◽

10.1515/nanoph-2020-0078 ◽

2020 ◽

Vol 9 (10) ◽

pp. 3357-3365 ◽

Cited By ~ 1

Author(s):

Shaohua Dong ◽

Qing Zhang ◽

Guangtao Cao ◽

Jincheng Ni ◽

Ting Shi ◽

...

Keyword(s):

High Speed ◽

High Efficiency ◽

Incident Angle ◽

Reciprocal Lattice ◽

Plasmonic Waveguide ◽

Optical Diffraction ◽

Local Dynamic ◽

Phase Gradient ◽

On Chip ◽

Plasmon Polaritons

AbstractPlasmons, as emerging optical diffraction-unlimited information carriers, promise the high-capacity, high-speed, and integrated photonic chips. The on-chip precise manipulations of plasmon in an arbitrary platform, whether two-dimensional (2D) or one-dimensional (1D), appears demanding but non-trivial. Here, we proposed a meta-wall, consisting of specifically designed meta-atoms, that allows the high-efficiency transformation of propagating plasmon polaritons from 2D platforms to 1D plasmonic waveguides, forming the trans-dimensional plasmonic routers. The mechanism to compensate the momentum transformation in the router can be traced via a local dynamic phase gradient of the meta-atom and reciprocal lattice vector. To demonstrate such a scheme, a directional router based on phase-gradient meta-wall is designed to couple 2D SPP to a 1D plasmonic waveguide, while a unidirectional router based on grating metawall is designed to route 2D SPP to the arbitrarily desired direction along the 1D plasmonic waveguide by changing the incident angle of 2D SPP. The on-chip routers of trans-dimensional SPP demonstrated here provide a flexible tool to manipulate propagation of surface plasmon polaritons (SPPs) and may pave the way for designing integrated plasmonic network and devices.

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Implementation analysis of IoT-based offloading frameworks on cloud/edge computing for sensor generated big data

Complex & Intelligent Systems ◽

10.1007/s40747-021-00434-6 ◽

2021 ◽

Author(s):

Karan Bajaj ◽

Bhisham Sharma ◽

Raman Singh

Keyword(s):

High Speed ◽

Smart Cities ◽

Fog Computing ◽

Edge Computing ◽

Computation Offloading ◽

Performance Parameters ◽

Iot Applications ◽

Time Sensitivity ◽

Implementation Analysis ◽

Increasing Demand

AbstractThe Internet of Things (IoT) applications and services are increasingly becoming a part of daily life; from smart homes to smart cities, industry, agriculture, it is penetrating practically in every domain. Data collected over the IoT applications, mostly through the sensors connected over the devices, and with the increasing demand, it is not possible to process all the data on the devices itself. The data collected by the device sensors are in vast amount and require high-speed computation and processing, which demand advanced resources. Various applications and services that are crucial require meeting multiple performance parameters like time-sensitivity and energy efficiency, computation offloading framework comes into play to meet these performance parameters and extreme computation requirements. Computation or data offloading tasks to nearby devices or the fog or cloud structure can aid in achieving the resource requirements of IoT applications. In this paper, the role of context or situation to perform the offloading is studied and drawn to a conclusion, that to meet the performance requirements of IoT enabled services, context-based offloading can play a crucial role. Some of the existing frameworks EMCO, MobiCOP-IoT, Autonomic Management Framework, CSOS, Fog Computing Framework, based on their novelty and optimum performance are taken for implementation analysis and compared with the MAUI, AnyRun Computing (ARC), AutoScaler, Edge computing and Context-Sensitive Model for Offloading System (CoSMOS) frameworks. Based on the study of drawn results and limitations of the existing frameworks, future directions under offloading scenarios are discussed.

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Optimization of Air Gap Length and Capacitive Auxiliary Winding in Three-Phase Induction Motors Based on a Genetic Algorithm

Energies ◽

10.3390/en14154407 ◽

2021 ◽

Vol 14 (15) ◽

pp. 4407

Author(s):

Mbika Muteba

Keyword(s):

Genetic Algorithm ◽

Design Process ◽

Power Factor ◽

High Speed ◽

High Efficiency ◽

Air Gap ◽

Element Analysis ◽

Three Phase ◽

High Torque ◽

Cage Induction Motor

There is a necessity to design a three-phase squirrel cage induction motor (SCIM) for high-speed applications with a larger air gap length in order to limit the distortion of air gap flux density, the thermal expansion of stator and rotor teeth, centrifugal forces, and the magnetic pull. To that effect, a larger air gap length lowers the power factor, efficiency, and torque density of a three-phase SCIM. This should inform motor design engineers to take special care during the design process of a three-phase SCIM by selecting an air gap length that will provide optimal performance. This paper presents an approach that would assist with the selection of an optimal air gap length (OAL) and optimal capacitive auxiliary stator winding (OCASW) configuration for a high torque per ampere (TPA) three-phase SCIM. A genetic algorithm (GA) assisted by finite element analysis (FEA) is used in the design process to determine the OAL and OCASW required to obtain a high torque per ampere without compromising the merit of achieving an excellent power factor and high efficiency for a three-phase SCIM. The performance of the optimized three-phase SCIM is compared to unoptimized machines. The results obtained from FEA are validated through experimental measurements. Owing to the penalty functions related to the value of objective and constraint functions introduced in the genetic algorithm model, both the FEA and experimental results provide evidence that an enhanced torque per ampere three-phase SCIM can be realized for a large OAL and OCASW with high efficiency and an excellent power factor in different working conditions.

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Research on Distance Transform and Neural Network Lidar Information Sampling Classification-Based Semantic Segmentation of 2D Indoor Room Maps

Sensors ◽

10.3390/s21041365 ◽

2021 ◽

Vol 21 (4) ◽

pp. 1365

Author(s):

Tao Zheng ◽

Zhizhao Duan ◽

Jin Wang ◽

Guodong Lu ◽

Shengjie Li ◽

...

Keyword(s):

Neural Network ◽

High Speed ◽

High Performance ◽

High Efficiency ◽

Semantic Segmentation ◽

Raspberry Pi ◽

Distance Transform ◽

Testing Stage ◽

Sampling Points ◽

Information Sampling

Semantic segmentation of room maps is an essential issue in mobile robots’ execution of tasks. In this work, a new approach to obtain the semantic labels of 2D lidar room maps by combining distance transform watershed-based pre-segmentation and a skillfully designed neural network lidar information sampling classification is proposed. In order to label the room maps with high efficiency, high precision and high speed, we have designed a low-power and high-performance method, which can be deployed on low computing power Raspberry Pi devices. In the training stage, a lidar is simulated to collect the lidar detection line maps of each point in the manually labelled map, and then we use these line maps and the corresponding labels to train the designed neural network. In the testing stage, the new map is first pre-segmented into simple cells with the distance transformation watershed method, then we classify the lidar detection line maps with the trained neural network. The optimized areas of sparse sampling points are proposed by using the result of distance transform generated in the pre-segmentation process to prevent the sampling points selected in the boundary regions from influencing the results of semantic labeling. A prototype mobile robot was developed to verify the proposed method, the feasibility, validity, robustness and high efficiency were verified by a series of tests. The proposed method achieved higher scores in its recall, precision. Specifically, the mean recall is 0.965, and mean precision is 0.943.

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Roller–rail parameters on the transverse vibration characteristics of super-high-speed elevators

Transactions of the Canadian Society for Mechanical Engineering ◽

10.1139/tcsme-2018-0083 ◽

2019 ◽

Vol 43 (4) ◽

pp. 535-543 ◽

Cited By ~ 2

Author(s):

Shunxin Cao ◽

Ruijun Zhang ◽

Shuohua Zhang ◽

Shuai Qiao ◽

Dongsheng Cong ◽

...

Keyword(s):

High Speed ◽

Relative Displacement ◽

Guide Rail ◽

Coupled Vibration ◽

Vibration Acceleration ◽

Vibration Model ◽

Vibration Problems ◽

Equivalent Method ◽

Relationship Of ◽

The Relationship

Interaction and wear between wheel and rail become increasingly serious with the increase in elevator speed and load. Uneven roller surface, eccentricity of rollers, and the looseness of rail brackets result in serious vibration problems of high-speed and super-high-speed elevators. Therefore, the forced vibration differential equation representing elevator guide rails is established based on Bernoulli–Euler theory, and the vibration equation of the elevator guide shoes and the car is constructed using the Darren Bell principle. Then, the coupled vibration model of guide rail, guide shoes, and car can be obtained using the relationship of force and relative displacement among these components. The roller–rail parameters are introduced into the established coupled vibration model using the model equivalent method. Then, the influence of roller–rail parameters on the horizontal vibration of super-high-speed elevator cars is investigated. Roller eccentricity and the vibration acceleration of the car present a linear correlation, with the amplitude of the car vibration acceleration increasing with the eccentricity of the roller. A nonlinear relationship exists between the surface roughness of the roller and the vibration acceleration of the car. Increased continuous loosening of the guide rail results in severe vibration of the car at the loose position of the support.

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