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Artigos de revistas sobre o tema "Overspeed"

Autor: Grafiati

Publicado: 7 de setembro de 2024

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1

Sidorov, A. A., V. I. Abolmasov, K. O. Kosolapov, A. V. Kuznetsov e M. A. Arkhipov. "Multifunctional Overspeed Protection Device". Power Technology and Engineering 55, n.º 4 (novembro de 2021): 494–97. http://dx.doi.org/10.1007/s10749-021-01387-z.

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2

Liao, Aihua, Xiaodong Chai e Jian Yang. "A Numerical Simulation of Elastoplastic Contact Analysis of Compressor by Overspeeding". Advances in Mechanical Engineering 6 (1 de janeiro de 2014): 176897. http://dx.doi.org/10.1155/2014/176897.

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This study analyzes the stress distribution of 3D elastoplastic contact problems by using the FE parametric quadratic programming (PQP) method derived from a 3D FE model based on parametric variational principle (PVP). We numerically analyze a 24-blade compressor by combining centrifugal loading with interference-fit one. To accelerate computation, calculation is simplified by structural modeling via multisubstructuring, aiming to deal with FE-simulated computer aided design (CAD) conveniently. We then analyze the relationships between the maximum residual stresses of the compressor posterior to prestressing and overspeed rpms, and we also study the distribution and magnitude of the contact stresses of the compressor in working conditions after overspeed prestressing. Moreover, we thoroughly discuss the distribution and magnitude of the contact stresses of shaft-shaft sleeve-impeller in working conditions. Relative displacement can be prevented and contact stress can be kept uniform due to the nonuniform initial amount of interference in overspeed prestressing. This paper summarizes the FEM simulation results and provides reference data for improving the design and processing of compressor impellers, indicating that overspeed is indispensable in manufacture.

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Cecília-Gallego, Pau, Adrián Odriozola, José Vicente Beltrán-Garrido e Jesús Álvarez-Herms. "Acute Effects of Different Overspeed Loads with Motorized Towing System in Young Athletes: A Pilot Study". Biology 11, n.º 8 (16 de agosto de 2022): 1223. http://dx.doi.org/10.3390/biology11081223.

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Overspeed is a training method used to improve running speed, although its effects are not supported by consensual scientific evidence. The overspeed stimulus can be boosted by several methods, including motorized towing devices. Our objectives were to analyze the acute effects of three overspeed loads in young athletes and to select optimal loads for training periods. Eight young athletes (16.73 ± 1.69 years) performed one unassisted sprint and three assisted sprints, and kinematic and biomechanical data were compared. Significant increases (p < 0.05) in step velocity and step length were found with 2, 4, and 5.25 kg in maximum running speed, flight time and horizontal distance from the first contact to the vertical projection of the center of mass with 4 and 5.25 kg. Significant time decreases were found in 5 m flying sprint and contact time with 4 and 5.25 kg, and no significant changes were observed in step rate. The individually recommended loads would be between 3.47 ± 0.68% and 6.94 ± 1.35% body weight. Even having limitations, we can understand this work and its results as a pilot study to replicate the methodology and the use of new devices to more broadly investigate the effects of overspeed.

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4

Wang, Li, Wentao Sun, Jie Zhao e Dichen Liu. "A Speed-Governing System Model with Over-Frequency Protection for Nuclear Power Generating Units". Energies 13, n.º 1 (31 de dezembro de 2019): 173. http://dx.doi.org/10.3390/en13010173.

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Overspeed is more likely to occur in the process of load rejection or large disturbances for nuclear steam turbines due to the large parameter range and low steam parameters, as well as the power of the low-pressure cylinder accounting for a high proportion of the total power. It is of great significance to study the overspeed characteristics of nuclear power plants (NPPs) to ensure the safe and stable operation of the unit and power grid. According to the characteristics of NPPs, the overspeed protection model and the super-acceleration protection model were established, which were added to the speed-governing system model. The response characteristics of the reactor, thermal system, steam turbine and speed-governing system in the process of load rejection or large disturbances of the power grid were analyzed and simulated. The results were compared using the simulation software personal computer transient analyzer (PCTRAN). The simulation results showed that quickly closing both the high and medium pressure regulating valves could effectively realize frequency control when load rejection or a large grid disturbance occurred. The over-acceleration protection cooperates with the super-acceleration protection to avoid the repeated opening/closing of the valves due to overspeed protection. This could effectively reduce the impact of large disturbances on the reactor, thermal system, and turbine.

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5

Stien, Nicolay, Morten Strate, Vidar Andersen e Atle Hole Saeterbakken. "Effects of Overspeed or Overload Plyometric Training on Jump Height and Lifting Velocity". Sports Medicine International Open 4, n.º 02 (1 de abril de 2020): E32—E38. http://dx.doi.org/10.1055/a-1116-0749.

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AbstractThe aim of this study was to examine the effects of overspeed or overload plyometric training on jump height and lifting velocity in resistance trained females without plyometric training experience. Fifty-six participants (age: 21.2±1.7 years; body mass: 65.1±8.2 kg; height: 168.0±5.9 cm) were randomly allocated to either an overspeed (n=18), overload (n=18), or passive control (n=16) group. The two training groups completed 18.7±1.7 sessions consisting of three different plyometric exercises with overspeed or overload over eight weeks. Apart from the external loading, the two training modalities were identical. Following the training period, the changes in the recorded variables were not significantly different from those in the control group, nor did the training groups differ from each other. The training groups improved peak and average lifting velocity in the 40 and 60% of body mass loading conditions (9.50–33.37%, p=<0.001–0.038), whereas only the average lifting velocity improved in the 80% of body mass loading condition (OS: 14.47%, p<0.001 and OL: 23.13%, p<0.001). No significant changes occurred in the control group (9.18–13.55%, P=0.062–0.980). Overspeed and overload plyometric training may be viable methods for improving lifting velocity, but not squat jump height, in a population without plyometric training experience.

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6

Jiang, Haicheng, Decheng Wang, Peng Cheng e Chenxi Shao. "Dynamics Analysis of a Double-Plunger-Type Turbine Overspeed Protection Mechanism". Applied Sciences 13, n.º 21 (3 de novembro de 2023): 11995. http://dx.doi.org/10.3390/app132111995.

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A double-plunger type overspeed protection mechanism has excellent performance in turbine overspeed protection, but the complicated operating principle thereof makes long-term use difficult. In this study, a dynamic model is established to explain the relationship between the motion state and the force situation. Through the analysis of the dynamic model, the specific process of the linked plunger for achieving overspeed protection with tripping action is determined, and the motion law of the inner and outer plungers is clarified. Additionally, the complete solution method and calculation procedure for the tripping speed of the submerged plunger are established, and the specific process for solving the relevant equations with numerical iteration is clarified. Finally, a rigid-flexible coupling virtual prototype model is established, which validates the conclusion that initial eccentric distance and spring stiffness are key factors affecting tripping speed and the motion process of inner and outer plungers.

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7

Eryilmaz, I., L. Pawsey e V. Pachidis. "Multidisciplinary methodology for turbine overspeed analysis". Aeronautical Journal 122, n.º 1257 (novembro de 2018): 1711–33. http://dx.doi.org/10.1017/aer.2018.100.

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ABSTRACTIn this paper, an integrated approach to turbine overspeed analysis is presented, taking into account the secondary air system dynamics and mechanical friction in a turbine assembly following an unlocated high-pressure shaft failure. The axial load acting on the rotating turbine assembly is a governing parameter in terms of overspeed protection since it governs the level of mechanical friction which acts against the turbine acceleration due to gas torque. The axial load is dependent on both the force coming from secondary air system cavities surrounding the disc and the force on the rotor blades. It is highly affected by secondary air system dynamics because rotor movement modifies the geometry of seals and flow paths within the network. As a result, the primary parameters of interest in this study are the axial load on the turbine rotor, the friction torque between rotating and static structures and the axial position of the rotor.Following an initial review of potential damage scenarios, several cases are run to establish the effect of each damage scenario and variable parameter within the model, with comparisons being made to a baseline case in which no interactions are modelled. This allows important aspects of the secondary air system to be identified in terms of overspeed prevention, as well as guidelines on design changes in current and future networks that will be beneficial for overspeed prevention.

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8

Kirke, Brian K., e Benoit Paillard. "Predicted and measured performance of a vertical axis wind turbine with passive variable pitch compared to fixed pitch". Wind Engineering 41, n.º 1 (15 de novembro de 2016): 74–90. http://dx.doi.org/10.1177/0309524x16677884.

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The performance of a 5-m diameter Darrieus vertical axis wind turbine was predicted using both a double multiple streamtube model and a two-dimensional unsteady Reynolds-averaged Navier–Stokes computational fluid dynamics simulation with constant rotational speed for a series of operational points. The actual performance was measured in both fixed and variable pitch modes. The aims were (1) to compare starting torque and peak efficiency in fixed and variable pitch modes and (2) to test an overspeed control mechanism. Starting torque was approximately three times higher in variable pitch mode and the maximum efficiency on some runs was significantly higher. The overspeed control mechanism functioned consistently as designed. Thus, variable pitch was shown to overcome two major disadvantages of normal fixed pitch vertical axis wind turbines, self-starting and overspeed control. Discrepancies between the predicted and measured results showed the importance of accurately assessing parasitic drag losses and the need for three-dimensional simulation to give reliable performance predictions.

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9

Moinuddin, Md Khaja. "Automatic Vehicle Overspeed Detection and Recognition". International Journal for Research in Applied Science and Engineering Technology 9, n.º VII (15 de julho de 2021): 914–23. http://dx.doi.org/10.22214/ijraset.2021.36501.

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Vehiсle speed detection is аn imроrtаnt раrt оf trаffiс mаnаgement system. It рlаys аn imроrtаnt rоle in trасking systems, аutоmаtiс videо surveillаnсe аnd аlsо tо аvоid соllisiоn. This рарer рrороses а methоd tо estimаte the sрeed оf vehiсles оn the highwаys аnd сity аreаs. The рrороsed methоd саn be effeсtively imрlemented tо соntrоl the оver sрeed vehiсles аnd tо fоund guilty in leаding tо trаffiс ассidents. Eасh vehiсle in the videо reсоrded by the саmerа is identified. А bоunding bоx is сreаted оn the identified vehiсle аnd its сentrоid сооrdinаtes аre mаrked. The аnаlysis оf sрeed is dоne using mаthemаtiсаl fоrmulаe whiсh аre embedded in the sоftwаre. The existing reseаrсh in this field hаs сertаin limitаtiоns. The first limitаtiоn is соnsumрtiоn оf а lоt оf memоry tо stоre videоs in the hаrd drive. The seсоnd limitаtiоn is inассurасy оf the system in unрleаsаnt weаther соnditiоns suсh fоg, hаze, rаin, аnd heаvy winds, etс. Sоme systems fаiled tо сrаte рrорer bоunding bоx аs it is neсessаry fоr ассurаte аnаlysis оf the mоtiоn оf the vehiсle аnd its speed. Another disadvantage is that shаdоw produced by vehicles on different lanes of the road causes a commotion, and the system detects the shаdоw as а different objeсt and creates а bounding bоx оvеr it.There аre оther hаrdwаre bаsed methоds suсh аs rаdаr gun аlsо.Соsine errоrs оссurred when the direсtiоn оf the vehiсle аnd the rаdаr gun dоesn’t mаtсh. The оbjeсtive оf the рrороsed wоrk is tо develор а system whiсh саn рrоvide the аlternаtive tо the rаdаr bаsed systems whiсh саn deteсt multiрle vehiсles аt the sаme time. We evаluаtеd the proposed method on various traffic videos and discovered that it accurately detects the speed of a vehicle and performs many state-of-the-art аррrоасhes.

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10

INOUE, Shinsuke, Hidemitsu NAYA, Tatsushi YABUUCHI, Naoki TAKAYAMA e Yuki SAITO. "Study of Electronizing Overspeed Detection for Elevator". Proceedings of the Transportation and Logistics Conference 2016.25 (2016): 1207. http://dx.doi.org/10.1299/jsmetld.2016.25.1207.

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11

Zheng, Wei, Yongpan Zhao, Yiyong Weng, Xing Duan e Haibin Jin. "Experiments on a crane overspeed protection device". IOP Conference Series: Materials Science and Engineering 612 (19 de outubro de 2019): 032074. http://dx.doi.org/10.1088/1757-899x/612/3/032074.

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12

Ebben, William P. "The Optimal Downhill Slope for Acute Overspeed Running". International Journal of Sports Physiology and Performance 3, n.º 1 (março de 2008): 88–93. http://dx.doi.org/10.1123/ijspp.3.1.88.

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Purpose:This study evaluated a variety of downhill slopes in an effort to determine the optimal slope for overspeed running.Methods:Thirteen NCAA Division III college athletes who participated in soccer, track, and football ran 40-yd (36.6-m) sprints, on downhill slopes of 2.1°, 3.3°, 4.7°, 5.8°, and 6.9° in random order. All sprints were timed using the Brower Timing System Speedtrap II. Data were analyzed with SSPS 15.0. A 1-way repeated-measures analysis of variance revealed significant main effects for the test slopes (P = .000). Bonferroni-adjusted pairwise comparisons determined that there were a number of differences between the hill slopes.Results:Analysis reveals that 40-yd sprints performed on hill slopes of approximately 5.8° were optimal compared with flatland running and the other slopes assessed (P < .05). Sprinting on a 5.8° slope increased the subjects’ maximal speed by an average of 0.35 s, resulting in a 6.5% ± 4.0% decrease in 40-yd sprint time compared with fatland running. Compared with the 4.7° slope, the 5.8° slope yielded a 0.10-s faster 40-yd sprint time, resulting in a 1.9% increase in speed.Conclusions:Those who train athletes for speed should use or develop overspeed hills with slopes of approximately 5.8° to maximize acute sprinting speed. The results of this study bring into question previous recommendations to use hills of 3° downhill slope for this form of overspeed training.

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13

Alexander, Marion J. L., e Robert Majdell. "The effect of overspeed training on sprinting speed". Journal of Biomechanics 22, n.º 10 (janeiro de 1989): 979. http://dx.doi.org/10.1016/0021-9290(89)90099-7.

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14

N, Mrs Priya, G. Sai Mani Kumar, B. Aravind Kumar, M. Vinay Kumar Reddy e B. Sree Harsha. "Review Paper on E-Traffic Police IoT Based Auto-Detection of Traffic Rule Violation". International Journal of Innovative Technology and Exploring Engineering 11, n.º 8 (30 de julho de 2022): 1–4. http://dx.doi.org/10.35940/ijitee.g9996.0711822.

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It is known fact that accidents are the major problem that is occurring now a days. Wearing helmets is one of the mandatory rule made by the government. Even after implementing these rules some of the bike riders are avoiding it. Because of this reason, we are seeing the increase of accidents. Also, due to slow reach of treatment accidents occurring at small areas are becoming fatal. current project looks to solve these problems. In this project a message will be sent to the rider that to wear the helmet, triple riding, signal jump, overspeed and also sends a message if driver isn’t in active mode. These accidents leads to significant amount of death and disability. In India, Avoiding traffic rules like triple riding, signal jump, overspeed are causing major accidents. All the systems focus on changes occur in movement of vechicles, and sends a message if the rider avoids any of the mentioned traffic rules, which have been already explained in the literature survey.

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15

Wen-tao LI, 厉文涛, 汤灏 Hao TANG e 周健 Jian ZHOU. "Research on Laser Velocimeter for Overspeed Detection on Highways". ACTA PHOTONICA SINICA 49, n.º 9 (2020): 912001. http://dx.doi.org/10.3788/gzxb20204909.0912001.

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16

Cenitagoya, A., A. Remirez, M. Cabello e I. Esnal. "Novel Elevator Overspeed Governor Design and Multibody Dynamic Analysis". Journal of Testing and Evaluation 50, n.º 5 (4 de abril de 2022): 20210698. http://dx.doi.org/10.1520/jte20210698.

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17

Xun, Jing, Mingliang Chen, Yafei Liu e Fan Liu. "An Overspeed Protection Mechanism for Virtual Coupling in Railway". IEEE Access 8 (2020): 187400–187410. http://dx.doi.org/10.1109/access.2020.3029147.

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18

Eryilmaz, I., e V. Pachidis. "Turbine thermomechanical modelling during excessive axial movement and overspeed". Aeronautical Journal 123, n.º 1260 (fevereiro de 2019): 248–64. http://dx.doi.org/10.1017/aer.2018.162.

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ABSTRACTThis manuscript discusses the numerical (finite element) and analytical modelling of structural interactions between gas turbine components in case of excessive axial movement and overspeed. Excessive axial movement, which may occur after a shaft failure, results in contact between rotating and static turbine components under high forces. These forces create friction which can act as a counter torque, potentially retarding the ‘free-rotating’ components. The study is based on a shaft failure scenario of a ‘three-shaft’, high ‘bypass’ ratio, civil ‘large-fan’ engine. Coupled analytical performance and friction methods are used as stand-alone tools to investigate the effect of rubbing between rotating and stationary components. The method is supported by ‘high-fidelity’, ‘three-dimensional’, thermomechanical finite element simulations using LS-DYNA software. The novelty of the work reported herein lies in the development of a generalised modelling approach that can produce useful engine design guidelines to minimise the terminal speed of a free running turbine after an unlocated shaft failure. The study demonstrates the advantage of using a fast analytical formulation in a design space exploration, after verifying the analytical model against finite element simulation results. The radius and the area of a stationary seal platform in the turbine assembly are changed systematically and the design space is explored in terms of turbine acceleration, turbine dislocation rate and stationary component mass. The radius of the friction interface increases due to the increasing radius of the nozzle guide vane flow path and stationary seal platform. This increases the frictional torque generated at the interface. It was found that if the axial dislocation rate of the free running turbine wheel is high, the resulting friction torque becomes more effective as an overspeed prevention mechanism. Reduced contact area results in a higher axial dislocation rate and this condition leads to a design compromise between available friction capacity, during shaft failure contact and seal platform structural integrity.

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19

Alhaq, Habib, Esa Apriaskar e Djuniadi Djuniadi. "Overspeed Detection Using Arduino Uno-based IR Infrared Sensor". Circuit: Jurnal Ilmiah Pendidikan Teknik Elektro 7, n.º 2 (25 de agosto de 2023): 189. http://dx.doi.org/10.22373/crc.v7i2.16409.

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The goal of this project is to measure the speed of an object as it passes through the sensor being utilized. The tool that will be developed as a result of this project has already been designed in software simulation to ensure that it will work as intended. This device uses two infrared sensors as input signals to be processed in accordance with orders.I will be connected to an Arduino Uno through a middle whiteboard as a communication hub between various parts. The parameter used in this tool is the movement of the object going through the infrared sensor because that is what is measured when an object goes through the sensor in this tool. The input data will be processed and then shown on the programmed I2C 16x2 LCD to show the output signal that results from processing the input signal. Making this tool will allow users to minimize unintended incidents and control their speed while driving.

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20

Yan, Xiangwu, Linlin Yang e Tiecheng Li. "The LVRT Control Scheme for PMSG-Based Wind Turbine Generator Based on the Coordinated Control of Rotor Overspeed and Supercapacitor Energy Storage". Energies 14, n.º 2 (19 de janeiro de 2021): 518. http://dx.doi.org/10.3390/en14020518.

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With the increasing penetration level of wind turbine generators (WTGs) integrated into the power system, the WTGs are enforced to aid network and fulfill the low voltage ride through (LVRT) requirements during faults. To enhance LVRT capability of permanent magnet synchronous generator (PMSG)-based WTG connected to the grid, this paper presents a novel coordinated control scheme named overspeed-while-storing control for PMSG-based WTG. The proposed control scheme purely regulates the rotor speed to reduce the input power of the machine-side converter (MSC) during slight voltage sags. Contrarily, when the severe voltage sag occurs, the coordinated control scheme sets the rotor speed at the upper-limit to decrease the input power of the MSC at the greatest extent, while the surplus power is absorbed by the supercapacitor energy storage (SCES) so as to reduce its maximum capacity. Moreover, the specific capacity configuration scheme of SCES is detailed in this paper. The effectiveness of the overspeed-while-storing control in enhancing the LVRT capability is validated under different levels of voltage sags and different fault types in MATLAB/Simulink.

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Bai, Baoxue, Zhuang Xiao, Qingyuan Wang, Pengfei Sun e Xiaoyun Feng. "Multi-Objective Trajectory Optimization for Freight Trains Based on Quadratic Programming". Transportation Research Record: Journal of the Transportation Research Board 2674, n.º 11 (10 de setembro de 2020): 466–77. http://dx.doi.org/10.1177/0361198120937307.

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The overspeed protection, smooth driving, punctuality, and energy efficiency of freight trains largely depend on their trajectory optimization. This paper proposes a multi-objective optimization model, which maximizes the weighted sum of energy efficiency, punctuality, and driving smoothness. Model constraints systematically cover many practical conditions, including varying line resistance, overspeed protection, discrete neutral zones, and nonlinear traction and electric braking characteristics. Electric braking and pneumatic braking are distinguished in the freight train model, and the utilization of feedback braking energy is also considered. By nonlinear approximation, the proposed multi-objective optimization model is solved by the quadratic programming (QP) algorithm, and optimized trajectories are obtained. Numerical simulation demonstrates the correctness and effectiveness of the proposed method. Comparisons with two actual trials show that the energy efficiency and driving smoothness of the proposed method are better than that of the drivers’ operation with the same journey time. In addition, the algorithm has a short computation time, which has the potential to be integrated for on-board devices such as the driver advisory system (DAS).

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Tang, Ran, Shuren Wang, Biao Xiao e Heng Wang. "Troubleshooting and Improvement of Mechanical Overspeed Shutdown of Diesel Generator". Journal of Physics: Conference Series 2187, n.º 1 (1 de fevereiro de 2022): 012036. http://dx.doi.org/10.1088/1742-6596/2187/1/012036.

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Abstract This paper introduced the components and functions of control components of a ship automatic power station, with an analysis of the control principle of such station. The fault treatment method and troubleshooting process are elaborated based on mechanical overspeed automatic shutdown fault of the generator. Finally, in view of the problem of 4K6 relay, appropriate improvement measures are proposed.

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Ikaningsih, Manty Aldilani, e War’an Rosihan. "Penggunaan Styrofoam sebagai Material Bilah Turbin Angin". ROTASI 21, n.º 1 (29 de abril de 2019): 23. http://dx.doi.org/10.14710/rotasi.21.1.23-29.

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Percobaan pembuatan bilah turbin angin dengan bahan kayu dan styrofoam dilakukan dengan tujuan agar pada kecepatan tertentu bilah dapat rusak. Kerusakan ini dipusatkan pada bagian styrofoam yang memiliki tingkat ketahanan pembebanan di bawah kayu. Kerusakan bilah tersebut nantinya akan melindungi generator agar tidak mengalami overspeed. Pada penelitian ini, desain bilah turbin angin yang digunakan berasal dari lembaga penelitian Lentera Angin Nusantara. Bilah turbin angin yang dibuat adalah tipe taperless, dimana ukuran bilah sama dari pangkal hingga ujung. Modifikasi bilah turbin angin dilakukan berdasarkan hasil simulasi performa bilah turbin angin dengan menggunakan perangkat lunak QBlade. Pada hasil simulasi ditunjukkan bahwa sumbangsih terbesar harga torsi total berasal dari torsi elemental dari bagian bilah pada posisi 50% - 100% panjang bilah. Berdasarkan hasil simulasi performa bilah turbin angin tersebut, maka bilah turbin angin yang dibuat dari bahan dasar kayu dimodifikasi dari bagian tengah hingga bagian ujung belakang dengan menggunakan styrofoam. Harapannya modifikasi tersebut akan mencegah overspeed pada generator dan memusatkan kerusakan di bagian bilah yang terbuat dari styrofoam akibat gaya dorong saat kecepatan angin cukup tinggi. Jika uji lapangan berhasil, maka pemusatan letak kegagalan bilah akan meminimalisir kerusakan (patahnya) bilah di bagian yang tidak terprediksi.

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FUKUDA, Toshiyuki, Tetsuya NAKAYAMA, Yuki NOZAWA, Takashi ABE e Koichi MIYATA. "Mechanism and Analysis of Tensioning Device for Elevator Overspeed Governor". Proceedings of the Elevator, Escalator and Amusement Rides Conference 2018 (2018): 101. http://dx.doi.org/10.1299/jsmeearc.2018.101.

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Johnson, R. M., J. H. Chow e M. V. Dillon. "Pelton Turbine Deflector Overspeed Control for a Small Power System". IEEE Transactions on Power Systems 19, n.º 2 (maio de 2004): 1032–37. http://dx.doi.org/10.1109/tpwrs.2004.825918.

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李, 海祯. "Analysis for Overspeed Problem of Electrombile Based on TRIZ Theory". Mechanical Engineering and Technology 05, n.º 03 (2016): 247–52. http://dx.doi.org/10.12677/met.2016.53029.

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Pawsey, Lucas, David John Rajendran e Vassilios Pachidis. "Characterisation of turbine behaviour for an engine overspeed prediction model". Aerospace Science and Technology 73 (fevereiro de 2018): 10–18. http://dx.doi.org/10.1016/j.ast.2017.11.037.

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Hure, Nikola, Mario Vašak, Mate Jelavić e Nedjeljko Perić. "Wind turbine overspeed protection based on polytopic robustly invariant sets". Wind Energy 19, n.º 9 (11 de dezembro de 2015): 1713–31. http://dx.doi.org/10.1002/we.1948.

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Y, Rakesh Kumar, e Suma Latha P. "Vehicle Overspeed Detection and Number Plate Extraction Using Raspberry Pi". International Journal for Research in Applied Science and Engineering Technology 11, n.º 6 (30 de junho de 2023): 3792–96. http://dx.doi.org/10.22214/ijraset.2023.54195.

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Abstract: The worst possible scenario for a road user is a traffic accident. The majority of fatal incidents are caused by overspeeding. Vehicles travelling faster are more likely to be involved in collisions. In the past, numerous gadgets were employed to catch reckless highway driving. Most of the approaches require human concentration and involve a lot of effort, which is difficult to implement With the help of this project, we hope to create a system for the early identification and warning of reckless driving-related unsafe vehicle driving patterns. The entire implementation requires an IR transmitter, an IR receiver, a control Raspberry Pi. The police employ a system to determine the speed limit based on the volume of traffic in the area. The time taken by the vehicle to travel from one set point to the other is calculated by control circuit and depending on that value the speed of the vehicle is calculated. Moreover, if the vehicle crosses the speed limit, it captures the image and extract the details of number plate using “Optical Character Recognition

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Wang, Jin, Jie Yan, Yongqian Liu e Zhicheng Xu. "Inertia Evaluation of Wind Farm Under Overspeed Power Shedding Control". Journal of Physics: Conference Series 2564, n.º 1 (1 de agosto de 2023): 012042. http://dx.doi.org/10.1088/1742-6596/2564/1/012042.

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Abstract As the penetration rate of wind power generation gradually increases in most grids, it is necessary to evaluate wind farms’ inertia to provide inertia information for electric grids and boost grid stability. This paper firstly models the inertia control mode of overspeed power shedding, which can realize the inertia control under the operation of different blade tip speed ratios, so that the wind turbine has a high inertia support capability. Then the energy change process in the inertia control process is analyzed, and the virtual inertia time constant is derived to evaluate a single unit’s inertia. Finally, a simple wind condition and the wind farm’s inertia control requirements in a day are simulated using an equivalent model, and the inertia level of the wind farm is calculated. The proposed research approach can alleviate the sophistication of inertia evaluation which also effectively consider the influence of inertia control.

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Cai, Enyu, Yunqiang Yan, Lei Dong e Xiaozhong Liao. "A Control Scheme with the Variable-Speed Pitch System for Wind Turbines during a Zero-Voltage Ride Through". Energies 13, n.º 13 (30 de junho de 2020): 3344. http://dx.doi.org/10.3390/en13133344.

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Zero-voltage ride through (ZVRT) is the extreme case of low-voltage ride through (LVRT), which represents the optimal grid-connection capability of wind turbines (WTs). Enforcing ZVRT will improve the dynamic performance of WTs and therefore significantly enhance the resiliency of renewable-rich grids. A control scheme that includes a pitch system is an essential control aspect of WTs riding through voltage dips; however, the existing control scheme with a pitch system for LVRT cannot distinguish between a ZVRT status and a power-loss condition, and, consequently, does not meet the ZVRT requirements. A system-level control scheme with a pitch system for ZVRT that includes pitch system modeling, control logic, control circuits, and overspeed protection control (OPC) is proposed in this paper for the first time in ZVRT research. Additionally, the field data are shared, a fault analysis of an overspeed accident caused by a voltage dip that describes the operating status at the WT-collapse moment is presented, and some existing WT design flaws are revealed and corrected by the fault analysis. Finally, the pitching performance during a ZVRT, which significantly affects the ZVRT performance of the WT, is obtained from laboratory and field tests. The results validate the effectiveness of the proposed holistic control scheme.

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Hodson, H. P., e J. S. Addison. "Wake–Boundary Layer Interactions in an Axial Flow Turbine Rotor at Off-Design Conditions". Journal of Turbomachinery 111, n.º 2 (1 de abril de 1989): 181–92. http://dx.doi.org/10.1115/1.3262254.

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A series of experimental investigations has been undertaken in a single-stage low-speed turbine. The measurements involved rotor blade surface flow visualization, surface-mounted hot-film anemometry, and exit pitot traverses. The effects of varying the flow coefficient and Reynolds number upon the performance of the rotor blade at midspan are described. At the design flow coefficient (φ = 0.495), the rotor pressure surface flow may be regarded as laminar, while on the suction surface, laminar flow gives way to unsteady stator wake-induced transition and then to turbulent flow. Over the range of Reynolds numbers investigated (1.8×105–3.3×105), the rotor midspan performance is dominated by the suction surface transition process; suction surface separation is prevented and the rotor midspan loss coefficient remains approximately constant throughout the range. At positive incidence, suction surface leading edge separation and transition are caused by a velocity overspeed. Reattachment occurs as the flow begins to accelerate toward the throat. The loss associated with the separation becomes significant with increasing incidence. At negative incidence, a velocity overspeed causes leading edge separation of the pressure side boundary layers. Reattachment generally occurs without full transition. The suction surface flow is virtually unaffected. Therefore, the rotor midspan profile loss remains unchanged from the zero incidence value until pressure side stall occurs.

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Zhou, Chuangxin, Shengfeng Zhao e Xingen Lu. "Flow Mechanism of a New Concept Transonic Tandem Fan Stage under the Design and Off-Design Conditions". Aerospace 9, n.º 11 (3 de novembro de 2022): 686. http://dx.doi.org/10.3390/aerospace9110686.

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A detailed numerical simulation of a transonic tandem fan stage was conducted, and the change rule of the flow structure inside the fan stage under the design and off-design conditions was discussed to determine the internal flow mechanisms. The results demonstrate that the total pressure ratio of the fan stage steadily increases with the rotating speed, exhibiting an approximately quadratic growth rate. The peak efficiency reaches the maximum at 80% design speed and rapidly declines under the overspeed condition. Furthermore, the peak efficiency point for different rotating speeds was investigated. The changes in the flow features, such as shock wave/boundary layer interaction and radial migration of low-energy fluids, mainly determine the isentropic efficiency at the higher span. At the middle-lower span, higher or lower inflow relative Mach number increases the flow loss. Moreover, the strength of the tip vortex and wake affect the flow loss at the lower span, while the radial motion of the former flow structure dominated by the equivalent inertial force is another essential factor. Under the high-speed condition, the gain of a high-throughflow fan on choke mass flow can be exhibited. However, the throat position causes an abnormal change under the overspeed condition.

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Zhong, Ming En, Han Chi Hong e Jian Jin Cai. "Study on Changes of Vehicle Driving Behavior Characteristics for Alcohol Used Drivers". Advanced Materials Research 1030-1032 (setembro de 2014): 2115–20. http://dx.doi.org/10.4028/www.scientific.net/amr.1030-1032.2115.

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Drunk driving is proved to be dangerous for traffic transportation safety. However, there are still no specific conclusions about what changes do drinking make to each kind of driving behaviors. This paper set out a drunk states induce program and a simulated driving experiment to measure the data about driving speed, overspeed driving probability, brake frequency, probability of deceleration for avoidance and probability of running red lights when the drivers were in different degree of drunk states. Results showed that driving speed increases significantly only in state of heavy drunk while decreases slightly in state of moderate drunk. Overspeed probability grows higher as the drivers drink more. Brake frequency increases slightly in state of light drunk, but has no obvious change in state of moderate drunk, however decreases significantly in state of heavy drunk. Probability of deceleration for avoidance decreases a little in state of light drunk but significantly in state of heavy drunk, however increases in state of moderate dunk. Probability of running red lights increases significantly only in state of heavy drunk, but has no obvious change in both states of light drunk and moderate drunk. All these support a conclusion that drinking has different influences on each kind of driving behaviors, which perform differently for traffic transportation safety. Judgments for drunk driving related issues should be decided on each specific matter.

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McMahon, Niall M., Patrick Rogers, Raymond Byrne, Paul MacArtain e Lawrence D. Staudt. "Technical Note: Blade Integrated Overspeed Protection for Small Turbines — Experimental Observations". Wind Engineering 38, n.º 1 (fevereiro de 2014): 117–20. http://dx.doi.org/10.1260/0309-524x.38.1.117.

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Hejzlar, Pavel, Olga Ubra e Jaroslav Ambroz. "A computer program for transient analysis of steam turbine generator overspeed". Nuclear Engineering and Design 144, n.º 3 (novembro de 1993): 469–85. http://dx.doi.org/10.1016/0029-5493(93)90043-9.

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GOJANOVIC, BORIS, REBECCA SHULTZ, FRANCOIS FEIHL e GORDON MATHESON. "Overspeed HIIT in Lower-Body Positive Pressure Treadmill Improves Running Performance". Medicine & Science in Sports & Exercise 47, n.º 12 (dezembro de 2015): 2571–78. http://dx.doi.org/10.1249/mss.0000000000000707.

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Wang, Xin, e Rui Ying Zhao. "A Reverse Driving Control Method for Hydrostatic Mobile Machinery". Applied Mechanics and Materials 135-136 (outubro de 2011): 140–45. http://dx.doi.org/10.4028/www.scientific.net/amm.135-136.140.

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A reverse driving control method for one type of hydrostatic mobile machinery is devised in this paper. Based on the analysis of dynamics of stopping process, the relationship between engine speed and pump displacement is established. To restrict the peak value of engine overspeed within the region of the allowable value, an offline parameter determination approach complied to the requirements of average stopping deceleration is developed. The online control method using the selected parameter is presented. A flow diagram is given to illustrate the control method.

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Ma, Shi Jun, Hao Wang, Jian She Tian e Li Meng. "Research on Analysis and Control Strategy of High Frequency Phenomenon in an Isolated Power Grid". Advanced Materials Research 694-697 (maio de 2013): 2073–79. http://dx.doi.org/10.4028/www.scientific.net/amr.694-697.2073.

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An operation and control simulation platform for isolated power grid are set up, which is based on the detailed models of the boiler, turbine, Coordinated Control System (CCS), Digital Electric-hydraulic Control system (DEH), Overspeed Protection Controller (OPC) and so on. By means of simulation, the accuracy of this platform is verified and the cause leading to high frequency of the isolated power grid is proposed..In addition, the control strategy for high frequency of isolated power grid based on wide area measurement data is proposed.

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Mazur, Robert E., e Guy Ankerl. "Urbanization Overspeed in Tropical Africa 1970-2000: Facts, Social Problems, and Policy." Contemporary Sociology 17, n.º 3 (maio de 1988): 354. http://dx.doi.org/10.2307/2069649.

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Ma, Mengdi, Dasheng Wei, Yanrong Wang, Di Li e Hui Zhang. "Strength Evaluation and Failure Analysis of the Vortex Reducer under Overspeed Condition". Aerospace 8, n.º 12 (13 de dezembro de 2021): 394. http://dx.doi.org/10.3390/aerospace8120394.

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Rotating parts of aeroengines need to have a high speed margin according to the civil aviation airworthiness regulations. Previous studies on burst speed are based on mechanical properties of standard specimens. In this paper, a new method for predicting burst speed by means of a tensile test of a simulative specimen is proposed, and the predicted results are compared with the traditional method. The results show that the stress gradient of the designed simulative specimen and the assessment location of vortex reducer are in good agreement, which indicates that they have similar stress characteristics. The burst speed predicted by the new method is greater than the traditional method. Both prediction methods can provide a reference for such a structure in the design stage. In addition, the overspeed test of a vortex reducer is carried out, and the results verify that it still has sufficient strength reserves at 120% relative speed.

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Chen, Hao, Hui-Jun Tan, Qi-Fan Zhang e Yue Zhang. "Throttling Process and Buzz Mechanism of a Supersonic Inlet at Overspeed Mode". AIAA Journal 56, n.º 5 (maio de 2018): 1953–64. http://dx.doi.org/10.2514/1.j056674.

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Yonggyun Shin, Ryu Jun Beom e Hahn,Doug-Woong. "A Prediction of Overspeed Driving on the Road with Driving Anger Scale". Korean Journal of Health Psychology 14, n.º 1 (março de 2009): 159–73. http://dx.doi.org/10.17315/kjhp.2009.14.1.010.

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Appell, Bo, Harald Hoffeld e Achim Menne. "New method for the protection of gas turbines against overload and overspeed". Technology, Law and Insurance 4, n.º 1-2 (março de 1999): 121–25. http://dx.doi.org/10.1080/135993799349216.

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Nozhnitsky, Y. A., e A. N. Servetnik. "Prevention of Hazardous Failure of the Turbine Rotor Due to Its Overspeed". IOP Conference Series: Materials Science and Engineering 449 (29 de novembro de 2018): 012025. http://dx.doi.org/10.1088/1757-899x/449/1/012025.

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Macaulay, M. R., J. R. Keener e R. Rothenberger. "EFFECT OF OVERSPEED HARNESS SUPPORTED TREADMILL TRAINING ON RUNNING ECONOMY AND PERFORMANCE." Medicine & Science in Sports & Exercise 27, Supplement (maio de 1995): S23. http://dx.doi.org/10.1249/00005768-199505001-00136.

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Qiao, Zhen, e Zhanfang Liu. "Research on a micro-trigger sensor for overspeed alarm and emergency protection". Measurement 149 (janeiro de 2020): 106995. http://dx.doi.org/10.1016/j.measurement.2019.106995.

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Sun, Heqing, Zhongsheng Hou e Dayou Li. "Coordinated Iterative Learning Control Schemes for Train Trajectory Tracking With Overspeed Protection". IEEE Transactions on Automation Science and Engineering 10, n.º 2 (abril de 2013): 323–33. http://dx.doi.org/10.1109/tase.2012.2216261.

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Jong, Jyh-Cherng, Yung-Cheng (Rex) Lai, Cheng-Chung Young e Yu-Fu Chen. "Application of Fault Tree Analysis and Swiss Cheese Model to the Overspeed Derailment of Puyuma Train in Yilan, Taiwan". Transportation Research Record: Journal of the Transportation Research Board 2674, n.º 5 (16 de abril de 2020): 33–46. http://dx.doi.org/10.1177/0361198120914887.

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On October 21, 2018, a Puyuma express train went overspeed through a sharp curve and derailed in Yilan, Taiwan. This accident resulted in 18 fatalities and 267 injuries. Although such accidents occur once in a while worldwide, this case of an overspeed derailment from a train-set equipped with an automatic train protection (ATP) system (similar to the function of Positive Train Control (PTC) in the U.S.) is rare. A temporary investigation team was appointed by the Executive Yuan, the highest administrative organ in Taiwan, and the investigation was completed within 2 months. This paper presents the process, analysis, findings, and recommendations from the accident investigation. The accident was first analyzed using fault tree analysis to identify potential causes and contributing factors of this derailment. The results were then categorized into layers of defenses by using a Swiss cheese model. We further extended the original Swiss cheese model to a “time-dependent Swiss cheese model” to demonstrate how the barriers were penetrated at different times by incorporating the timestamps of important events. Another modified Swiss cheese model called “causal relationship Swiss cheese model” was presented to further demonstrate the causal relationships. With the proposed process and models, the immediate causes and contributing factors were quickly identified and presented in a way that could be easily understood by the general public. The results showed that the ATP system (or the PTC) cannot guarantee 100% safety. A review of the safety culture and corresponding procedures is important to ensure the safety of railway operations.

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Kundur, P., D. C. Lee, J. P. Bayne e P. L. Dandeno. "Impact of Turbine Generator Overspeed Controls on Unit Performance Under System Disturbance Conditions". IEEE Power Engineering Review PER-5, n.º 6 (junho de 1985): 28–29. http://dx.doi.org/10.1109/mper.1985.5526620.

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