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Wang, Dapeng, Shaogang Liu, Youguo He i Jie Shen. "Barrier Lyapunov Function-Based Adaptive Back-Stepping Control for Electronic Throttle Control System". Mathematics 9, nr 4 (6.02.2021): 326. http://dx.doi.org/10.3390/math9040326.
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This paper presents an adaptive constraint control approach for Electronic Throttle Control System (ETCS) with asymmetric throttle angle constraints. The adaptive constraint control method, which is based on barrier Lyapunov function (BLF), is designed not only to track the desired throttle angle but also to guarantee no violation on the throttle angle constraints. An ETC mathematic model with complex non-linear system is considered and the asymmetric barrier Lyapunov function (ABLF) is introduced into the design of the controller. Based on Lyapunov stability theory, it can be concluded that the proposed controller can guarantee the stability of the whole system and uniformly converge the state error to track the desired throttle angle. The results of simulations show that the proposed controller can ensure that there is no violation on the throttle angle constraints.
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Wan, Junli. "Nonlinear Control of Electronic Throttle Based on Backstepping Approach". American Journal of Electromagnetics and Applications 4, nr 1 (2016): 1. http://dx.doi.org/10.11648/j.ajea.20160401.11.
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Zuti, Zhang, Cao Shuping, Luo Xiaohui, Shi Weijie i Zhu Yuquan. "New approach of suppressing cavitation in water hydraulic components". Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 231, nr 21 (12.07.2016): 4022–34. http://dx.doi.org/10.1177/0954406216657847.
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Cavitation frequently appears in high pressure water hydraulic components and leads to serious hydraulic erosions and horrible hydrodynamic noises. In this paper, a novel approach of suppressing cavitation was proposed, inducing the outlet pressure back to the orifice to improve the pressure distribution of throttle valves. In order to realize this approach, an optimized throttle valve chamber structure was designed. After that, the anticavitation performance of the valve was investigated. A theoretical cavitation cloud model was built based on bubble dynamics. In order to solve the mathematic cavitation model, the velocity field and pressure distribution of the novel throttle valve were simulated through Computational Fluid Dynamics(CFD). Combining the simulation results, the mathematic cavitation cloud model was solved through numerical calculations. Moreover, new indexes estimating cavitation intensity were proposed scientifically to investigate cavitation phenomenon. Then, the comparison of the novel throttle valve (with an innovative valve chamber) and traditional throttle valve in anticavitation performance was conducted under different conditions. Finally, the experiment about anticavitation performance was completed on the test rig. The calculation and experiment results indicated that the approach, inducing the outlet pressure back to the orifice, was effective in suppressing cavitation.
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Wang, Haihang, He Xu, Vishwanath Pooneeth i Xiao-Zhi Gao. "A Novel One-Camera-Five-Mirror Three-Dimensional Imaging Method for Reconstructing the Cavitation Bubble Cluster in a Water Hydraulic Valve". Applied Sciences 8, nr 10 (1.10.2018): 1783. http://dx.doi.org/10.3390/app8101783.
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In order to study the bubble morphology, a novel experimental and numerical approach was implemented in this research focusing on the analysis of a transparent throttle valve made by Polymethylmethacrylate (PMMA) material. A feature-based algorithm was written using the MATLAB software, allowing the 2D detection and three-dimensional (3D) reconstruction of bubbles: collapsing and clustered ones. The valve core, being an important part of the throttle valve, was exposed to cavitation; hence, to distinguish it from the captured frames, the faster region-based convolutional neural network (R-CNN) algorithm was used to detect its morphology. Additionally, the main approach grouping the above listed techniques was implemented using an optimized virtual stereo vision arrangement of one camera and five plane mirrors. The results obtained during this study validated the robust algorithms and optimization applied.
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Liu, Yong Gang, Zhen Zhen Lei, Li Lai Lu i Liang Chen. "Control System Integration for Dual Clutch Transmissions Based on Modular Approach". Applied Mechanics and Materials 390 (sierpień 2013): 419–23. http://dx.doi.org/10.4028/www.scientific.net/amm.390.419.
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Modular approach has been adopted in this paper to divide DCT transmission control unit into four modules, which are clutch control, synchronizer control, shift assembly control and vehicle control respectively. The function for each module has been analyzed and the control logic relations among these modules have also been established for modular integration. Moreover, the modeling process and control strategies for each module have been established for respective control objection. On this basis, the simulation model of transmission control unit for DCT has been built using the Matlab/Simulink platform, and the simulation has been carried out at given throttle opening. The results show that the control strategy of transmission control unit for DCT has been validated, which provides theoretical basis for DCT product development.
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Zhang, Feitie, Shoudao Huang, Xuelong Li i Fengjin Guan. "Research on Control-Oriented Modeling for Turbocharged SI and DI Gasoline Engines". Journal of Chemistry 2015 (2015): 1–11. http://dx.doi.org/10.1155/2015/765083.
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In order to analyze system performance and develop model-based control algorithms for turbocharged spark ignition and direct injection (SIDI) gasoline engines, a control oriented mean value model is developed and validated. The model is constructed based on theoretical analysis for the different components, including the compressor, turbine, air filter, intercooler, throttle, manifold, and combustion chamber. Compressor mass flow and efficiency are modeled as parameterized functions. A standard nozzle model is used to approximate the mass flow through the turbine, and the turbine efficiency is modeled as a function of blade speed ratio (BSR). The air filter is modeled as a tube for capturing its pressure drop feature. The effectiveness number of transfer units (NTU) modeling method is utilized for the intercooler. The throttle model consists of the standard nozzle model with an effective area regressed to throttle position. Manifolds are modeled for their dynamically varying pressure state. For the cylinder, the air mass flow into cylinders, fuel mass, torque, and exhaust temperature are modeled. Compared to the conventional lookup table approach, transient dynamics error can be improved significantly through using the model from this work.
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Chopra, Kapil, V. Sahni i R. S. Mishra. "Energetic and Exergetic Based Comparison Multiple Evaporators with Compound Compression and Flash Intercooler with Individual or Multiple Throttle Valves". International Journal of Advance Research and Innovation 1, nr 1 (2013): 67–76. http://dx.doi.org/10.51976/ijari.111309.
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The utility of second law analysis on vapour compression refrigeration systems is well defined because it gives the idea for improvements in efficiency due to modifications in existing design in terms of reducing exergy destructions in the components. Due to effect of global warming and ozone depletion the comparison and impact of environmental friendly refrigerants (R507a, R410a, R290, R600, R600a, R1234yf, R404a, R125, R717, R152a and R407C) on multiple evaporators at different temperature with compound compression and flash intercooler with individual and multiple throttle valves is important for calculating first law and second law performance on the basis of energetic and exergetic approach. Comparison was done for multiple evaporators with compound compression and flash intercooler with individual throttle valves (system-1) and multiple evaporators with compound compression and flash intercooler with multiple throttle valves (system-2) in terms of coefficient of performance, rational efficiency and total system defect. It was observed that for all considered refrigerants second law first law efficiency of system-1 is lower than sytem-2 conversely system defect of system-1 is higher than system-2.In terms of energetic efficiency, rational efficiency and system defect for both systemsR407C shows minimum performance and performances of R600, R152a and R717 better with comparison of other selected refrigerants for system-1 and system-2. But R600 is highly inflammable and R717 is toxic in nature and restricted to limited applications, so R152a is suggested for both systems.
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B., Ashok, Denis Ashok S. i Ramesh Kumar C. "An Integrated Pedal Follower and Torque Based Approach for Electronic Throttle Control in a Motorcycle Engine". Engineering Journal 21, nr 1 (31.01.2017): 63–80. http://dx.doi.org/10.4186/ej.2017.21.1.63.
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Pluta, Janusz, i Marek Sibielak. "Testing of Throttle Valve Prototype Controlled by Piezoelectric Stack". Solid State Phenomena 177 (lipiec 2011): 47–64. http://dx.doi.org/10.4028/www.scientific.net/ssp.177.47.
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This paper aims to present the results of the testing a single-stage electrically actuated throttle valve, in which a piezoelectric stack was used for adjustment of the flow section area of the throttle aperture. The valve prototype was built based on a proprietary design, using the components of a standard manufactured overflow valve. The complete valve was designed on the basis of the results of simulation tests performed on a mathematical model. The constitutive equations presented herein, describing all critical phenomena and influences present in the component, were applied for the modelling of the piezoelectric stack. Laboratory tests were carried out to establish the valve’s characteristics, describing its usefulness for control of flow intensity. LabView software was used for measuring the data gathered. The test results, after conversion, were developed using the Matlab/Simuling software package. This paper presents the most notable results of the tests of a normally open valve equipped with a high-voltage piezoelectric stack. Based on the results obtained, the functional correlation between the volumetric flow rate, pressure drop in the throttling aperture and control signal input to the piezoelectric stack were determined. Due to the comprehensive approach involved, the material presented herein may be prove useful to designers of valves and hydraulic units using piezoelectric stacks for controlling their operating units.
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Smith, Shaun, James Knowles i Byron Mason. "Numerical continuation applied to internal combustion engine models". Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 234, nr 14 (12.06.2020): 3458–75. http://dx.doi.org/10.1177/0954407020928665.
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This paper proposes tools from bifurcation theory, specifically numerical continuation, as a complementary method for efficiently mapping the state-parameter space of an internal combustion engine model. Numerical continuation allows a steady-state engine response to be traced directly through the state-parameter space, under the simultaneous variation of one or more model parameters. By applying this approach to two nonlinear engine models (a physics-based model and a data-driven model), this work determines how input parameters ‘throttle position’ and ‘desired load torque’ affect the engine’s dynamics. Performing a bifurcation analysis allows the model’s parameter space to be divided into regions of different qualitative types of the dynamic behaviour, with the identified bifurcations shown to correspond to key physical properties of the system in the physics-based model: minimum throttle angles required for steady-state operation of the engine are indicated by fold bifurcations; regions containing self-sustaining oscillations are bounded by supercritical Hopf bifurcations. The bifurcation analysis of a data-driven engine model shows how numerical continuation could be used to evaluate the efficacy of data-driven models.
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Maldonado, Bryan P., Nan Li, Ilya Kolmanovsky i Anna G. Stefanopoulou. "Learning reference governor for cycle-to-cycle combustion control with misfire avoidance in spark-ignition engines at high exhaust gas recirculation–diluted conditions". International Journal of Engine Research 21, nr 10 (26.06.2020): 1819–34. http://dx.doi.org/10.1177/1468087420929109.
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Cycle-to-cycle feedback control is employed to achieve optimal combustion phasing while maintaining high levels of exhaust gas recirculation by adjusting the spark advance and the exhaust gas recirculation valve position. The control development is based on a control-oriented model that captures the effects of throttle position, exhaust gas recirculation valve position, and spark timing on the combustion phasing. Under the assumption that in-cylinder pressure information is available, an adaptive extended Kalman filter approach is used to estimate the exhaust gas recirculation rate into the intake manifold based on combustion phasing measurements. The estimation algorithm is adaptive since the cycle-to-cycle combustion variability (output covariance) is not known a priori and changes with operating conditions. A linear quadratic regulator controller is designed to maintain optimal combustion phasing while maximizing exhaust gas recirculation levels during load transients coming from throttle tip-in and tip-out commands from the driver. During throttle tip-outs, however, a combination of a high exhaust gas recirculation rate and an overly advanced spark, product of the dynamic response of the system, generates a sequence of misfire events. In this work, an explicit reference governor is used as an add-on scheme to the closed-loop system in order to avoid the violation of the misfire limit. The reference governor is enhanced with model-free learning which enables it to avoid misfires after a learning phase. Experimental results are reported which illustrate the potential of the proposed control strategy for achieving an optimal combustion process during highly diluted conditions for improving fuel efficiency.
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Jan, Ahmed Zubair, Krzysztof Kedzia i Muhammad Jamshed Abbass. "Fractional-Order PID Controller (FOPID)-Based Iterative Learning Control for a Nonlinear Boiler System". Energies 16, nr 3 (17.01.2023): 1045. http://dx.doi.org/10.3390/en16031045.
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For the boiler-turbine unit in power systems, a coordinated control structure plays a crucial role in maintaining the balance in supply and demand of energy, reducing pollutant emissions and optimizing energy efficiency. The matching requirements of the turbine and boiler, the wide range of load changes, and the cooperative operation of many devices in the power system pose many challenges to designing a coordinated control system for the boiler turbine system, thus making the control design a difficult task. In this paper, iterative learning control (ILC) is used to maintain the throttle pressure and megawatt output power of a boiler turbine at the desired set points by controlling the hybrid pattern design structure. Simulation results show that the proposed approach can maintain the desired set points, and the desired response can also be obtained faster by using the proposed approach compared to the ones available in the literature.
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Abdalkafor, Ahmed Subhi, i Khattab M. Ali Alheeti. "A hybrid approach for scheduling applications in cloud computing environment". International Journal of Electrical and Computer Engineering (IJECE) 10, nr 2 (1.04.2020): 1387. http://dx.doi.org/10.11591/ijece.v10i2.pp1387-1397.
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Cloud computing plays an important role in our daily life. It has direct and positive impact on share and update data, knowledge, storage and scientific resources between various regions. Cloud computing performance heavily based on job scheduling algorithms that are utilized for queue waiting in modern scientific applications. The researchers are considered cloud computing a popular platform for new enforcements. These scheduling algorithms help in design efficient queue lists in cloud as well as they play vital role in reducing waiting for processing time in cloud computing. A novel job scheduling is proposed in this paper to enhance performance of cloud computing and reduce delay time in queue waiting for jobs. The proposed algorithm tries to avoid some significant challenges that throttle from developing applications of cloud computing. However, a smart scheduling technique is proposed in our paper to improve performance processing in cloud applications. Our experimental result of the proposed job scheduling algorithm shows that the proposed schemes possess outstanding enhancing rates with a reduction in waiting time for jobs in queue list.
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Sabikan, Sulaiman Bin, Nawawi S. W i NAA Aziz. "Modelling of time-to collision for unmanned aerial vehicle using particles swarm optimization". IAES International Journal of Artificial Intelligence (IJ-AI) 9, nr 3 (1.09.2020): 488. http://dx.doi.org/10.11591/ijai.v9.i3.pp488-496.
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A method for the development of Time-to-Collision (TTC) mathematical model for outdoor Unmanned Aerial Vehicle (UAV) using Particles Swarm Optimization (PSO), are presented. TTC is the time required for a UAV either to collide with any static obstacle or completely stop without applying any braking control system when the throttle is fully released. This model provides predictions of time before UAV will collide with the obstacle in the same path based on their parameter, for instance, current speed and payload. However, this paper focus on the methodology of the implementation of PSO to develop the TTC model for 5 different set of payloads. This work utilizes a quadcopter as our testbed system, that equipped with a Global Positioning System (GPS) receiver unit, a flight controller with data recording capability and ground control station for real-time monitoring. The recorded onboard flight mission data for 5 different set of payloads has been analyzed to develop a mathematical model of TTC through the PSO approach. The horizontal ground speed, throttle magnitudes and flight time stamp are extracted from the on-board quadcopter flight mission. PSO algorithm is used to find the optimal linear TTC model function, while the mean square error is used to evaluate the best fitness of the solution. The results of the TTC mathematical model for each payload are described.
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Cha, Jihyoung, Erik Andersson i Alexis Bohlin. "A Numerical Approach to Optimize the Design of a Pintle Injector for LOX/GCH4 Liquid-Propellant Rocket Engine". Aerospace 10, nr 7 (23.06.2023): 582. http://dx.doi.org/10.3390/aerospace10070582.
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This study presents an optimal design approach of a pintle injector for a deep throttlable liquid-propellant rocket engine (LPRE). Even though the pintle injector is used in rocket engines, it has become more important since reusable launch vehicles (RLVs) recently became a trend due to their economic and environmental benefits. However, since many variables must be determined to design a pintle injector, optimizing the pintle injector design is complicated. For this, we design a pintle injector to optimize the performance parameters; the spray angle, vaporization distance, and Sauter mean diameter (SMD). To confirm the approach, we design a pintle injector using an optimization method based on convex quadratic programming (CQP) for a 1000 N thrust and a throttle ability of 5 to 1 LPRE with liquid oxygen and gaseous methane. Then, we verify the performance using a numerical simulation. Through this work, we check the effectiveness of the optimization method for a pintle injector design.
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Yuan, Rong Di, i Quan Quan Du. "A Real-Time Model of Crush Natural Gas Turbo Engine". Applied Mechanics and Materials 58-60 (czerwiec 2011): 2511–16. http://dx.doi.org/10.4028/www.scientific.net/amm.58-60.2511.
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A new approach is presented in this paper in which a Crush Natural Gas (CNG) Turbo Engine model based on Mean Value Model and transient dynamics are included. The model could simulate engine speed, torque, dynamic load, electronic throttle, turbo, temperature and emission conditions. The model was downloaded and run in a HIL platform joint with Labview and a CNG engine ECU. Simulation results indicate that it acquires good balance between Real-time response and dynamic accuracy, besides good comprehensive running status parameters including dynamic, mechanic, thermo and combustion. The model made it possible for electronic engineers to begin their works earlier to find solutions for power loss, high working temperature of CNG engine with more flexibility and lower bench test expense.
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Lee, Jin Woong, Su Chul Kim, Jooseon Oh, Woo-Jin Chung, Hyun-Woo Han, Ji-Tae Kim i Young-Jun Park. "Engine Speed Control System for Improving the Fuel Efficiency of Agricultural Tractors for Plowing Operations". Applied Sciences 9, nr 18 (17.09.2019): 3898. http://dx.doi.org/10.3390/app9183898.
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This study was conducted to develop a load-sensitive engine speed control system to maximize the fuel efficiency of an agricultural tractor. The engine speed controller was developed through a model-based design approach using a tractor simulation model. The simulated engine speed and torque values were measured with an average error range of 1.4–4.9% compared to results obtained from field experiments. Using the tractor model, the gain parameters of the proportional–integral (PI) controller were optimized under the step, ramp, and actual load conditions. The simulation results using the actual load showed that the engine speed could be adjusted to within 2–3% of the desired value using the proposed engine speed controller. The throttle control system was constructed using four parts of a tractor engine, a microprocessor with an engine speed control algorithm, a throttle actuator, and a data acquisition system. Using the developed system, the operating engine speed values showed an average 1.17 % error compared to the desired engine speed. Three fuel efficiency parameters were used for evaluating the fuel-saving performance of the control system: specific volumetric fuel consumption (SVFC), fuel consumption per tilled area (FCA), and fuel consumption per work hour (FC). The values for SVFC, FCA, and FC obtained from the engine speed control system during plowing operations were 23.03–57.87%, 4.11–42.06%, and −7.24–38.48%, respectively, showing an improvement over the same operations without the control system.
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Ottaviani, Marco, Luca Giammichele i Renato Ricci. "Design, Assembly and Testing of a Mobile Laboratory Based on a VTOL Scale Motorglider". Tecnica Italiana-Italian Journal of Engineering Science 65, nr 2-4 (30.07.2021): 414–21. http://dx.doi.org/10.18280/ti-ijes.652-440.
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The objective of this paper is to explain the design steps and performance analysis of a vertical take-off and landing (VTOL) unmanned air vehicle (UAV) based on a Pilatus B4 glider scale model. Energy consumption, forces and thrust analyses are carry out to determinate the perfect match between low take-off weight and high aerodynamic performance. As a first approach a complete analysis of glider aerodynamic performances are settle to understand and design a proper support for VTOL conversion. Longitudinal static stability is fulfilled by evaluating the center of gravity location with respect to neutral position, nevertheless dynamic stability, and V-n diagram in VTOL configuration are evaluated to guarantee a correct behavior during fixed wing flight mode. In addition, power requirements, motor thrust capability and tilt-motors servo assisted system performance are determinate in perspective of flight performance to find out the perfect transition from multirotor take-off and landing mode to fixed-wing flying state. For these purposes a test bench has being designed to evaluate thrust, electrical absorption and rpm motor behavior along the throttle range. Finally, the assembly and preliminary tests are performed in order to validate the VTOL and Forward flight capability.
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Gibergans-Báguena, José, Pablo Buenestado, Gisela Pujol-Vázquez i Leonardo Acho. "A Proportional Digital Controller to Monitor Load Variation in Wind Turbine Systems". Energies 15, nr 2 (13.01.2022): 568. http://dx.doi.org/10.3390/en15020568.
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Monitoring the variation of the loading blades is fundamental due to its importance in the behavior of the wind turbine system. Blade performance can be affected by different loads that alter energy conversion efficiency and cause potential safety hazards. An example of this is icing on the blades. Therefore, the main objective of this work is to propose a proportional digital controller capable of detecting load variations in wind turbine blades together with a fault detection method. An experimental platform is then built to experimentally validate the main contribution of the article. This platform employs an automotive throttle device as a blade system emulator of a wind turbine pitch system. In addition, a statistical fault detection algorithm is established based on the point change methodology. Experimental data support our approach.
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Xie, Fangwei, Erming Ding, Rui Xuan, Xinxing Zhang, Yixian Feng i Jie Zhu. "Influence rules of geometric parameters on deformation of valve slices in valve-controlled adjustable damping shock absorber". International Journal of Structural Integrity 9, nr 1 (5.02.2018): 107–18. http://dx.doi.org/10.1108/ijsi-04-2017-0025.
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Purpose The purpose of this paper is to study the influence rules of geometric parameters on deformation of valve slices. Design/methodology/approach Based on the theory of flexural deformation of elastic thin slice, differential functions of deformation for both single and multi-slices are given and derived in detail. Furthermore, the effects of geometric dimensions on deformation are analyzed particularly by using Matlab/simulink. Findings The results indicated that the deformation decreases with the increment of fixed ring radius ra, slice thickness h, and its number n. Meanwhile, the deformation increases with a rise of slice radius rb, throttle position rk, the radius ratio λ1 and thickness ratio λ2 of slices. Originality/value This research can provide some theoretical supports for the parametric and optimal design of adjustable damping shock absorber.
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Acho, Leonardo. "A Proportional Plus a Hysteretic Term Control Design: A Throttle Experimental Emulation to Wind Turbines Pitch Control". Energies 12, nr 10 (22.05.2019): 1961. http://dx.doi.org/10.3390/en12101961.
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Pitch control is a relevant issue in wind turbines to properly operate the angle of the blades. Therefore, this control system pitches the blades usually a few degrees every time the wind changes in order to keep the rotor blades at the required angle thus controlling the rotational speed of the turbine. All the same time, the control of the pitch angle is not easy due to the system behavior being highly nonlinear. Consequently, the main objective of this paper is to depict an easy to implement control design based on a proportional controller and a hysteretic term to an emulator pitch control system in wind turbines. This emulator is just an automotive throttle device. This mechanical body dynamically captures some hard non-linearities presented in pitch wind turbine mechanisms, such as backlash, asymmetrical non-lineal effects, friction, and load variations. Even under strong non-linear effects that are difficult to model, a proportional controller and a hysteretic term may satisfy the main control design objective. Hence, a recent control design is developed and applied to a throttle system. We invoke the Lyapunov theory to confirm stability of the resultant closed-loop system. In addition, the proposed control approach is completely implemented by using operational amplifiers. Hence, no digital units are required at all. Moreover, the cost of the developed experimental platform and its outcomes are inexpensive. According to the experimental results, the controller performance seems acceptable, and validating of the control contribution too. For instance, a settling-time of about 0.03 s to a unit step-response is obtained.
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Lim, Ducsun, Wooyeob Lee, Won-Tae Kim i Inwhee Joe. "DRL-OS: A Deep Reinforcement Learning-Based Offloading Scheduler in Mobile Edge Computing". Sensors 22, nr 23 (26.11.2022): 9212. http://dx.doi.org/10.3390/s22239212.
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Hardware bottlenecks can throttle smart device (SD) performance when executing computation-intensive and delay-sensitive applications. Hence, task offloading can be used to transfer computation-intensive tasks to an external server or processor in Mobile Edge Computing. However, in this approach, the offloaded task can be useless when a process is significantly delayed or a deadline has expired. Due to the uncertain task processing via offloading, it is challenging for each SD to determine its offloading decision (whether to local or remote and drop). This study proposes a deep-reinforcement-learning-based offloading scheduler (DRL-OS) that considers the energy balance in selecting the method for performing a task, such as local computing, offloading, or dropping. The proposed DRL-OS is based on the double dueling deep Q-network (D3QN) and selects an appropriate action by learning the task size, deadline, queue, and residual battery charge. The average battery level, drop rate, and average latency of the DRL-OS were measured in simulations to analyze the scheduler performance. The DRL-OS exhibits a lower average battery level (up to 54%) and lower drop rate (up to 42.5%) than existing schemes. The scheduler also achieves a lower average latency of 0.01 to >0.25 s, despite subtle case-wise differences in the average latency.
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Lu, Xiao-Jie, Hong-Ya Tuo i Zhong-Liang Jing. "Study on Terrain Awareness and Warning System Envelope Based on Pilot Reaction Model". Journal of Computational and Theoretical Nanoscience 13, nr 10 (1.10.2016): 6867–71. http://dx.doi.org/10.1166/jctn.2016.5639.
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To solve the problem of envelope threshold for Terrain Awareness and Warning System (TAWS), this approach builds a pilot reaction model which contains two models. Pilot reaction model is built through combining the pilot delay time model and the after-alert-operation model. Warning envelope which meets the criterion is acquired through simulations using the pilot reaction model. In the discussion part, three pilot reaction elements, joystick operation speed, pilot delay and throttle operation speed, are chosen for influence analysis on TAWS warning envelope. The root-mean-square error between practical flying data and this paper’s warning envelope is 0.9545 m/s which is smaller than the three-degree-of-freedom model’s 1.2335 m/s. The influence analysis results show that the faster operation speed and shorter pilot delay time will make the envelope move to the right and decrease the envelope’s slope. And the faster operation speed and shorter pilot delay time will enhance flight safety. But overload and pressure from the faster operation speed and less delay will reduce pilot and airplane safety Altitude factor is introduced to the pilot delay time model and pilot operation factors are introduced to the after-alert-operation model based on six-degree-of-freedom model. The setting of envelope needs a trade-off. Reaction elements analysis can provide a theoretical basis for TAWS warning envelope design.
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Beringer, Dennis B. "Issues in Using Off-the-Shelf Pc-Based Flight Simulation for Research and Training: Historical Perspective, Current Solutions and Emerging Technologies". Proceedings of the Human Factors and Ergonomics Society Annual Meeting 38, nr 1 (październik 1994): 90–94. http://dx.doi.org/10.1177/154193129403800117.
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Flight simulation has historically been an expensive proposition, particularly if out-the-window views were desired. Advances in computer technology have allowed a modular, off-the-shelf flight simulation (based on 80486 processors) to be assembled that has been adapted, with minimal effort, for conducting general-aviation research. This simulation includes variable flight instrumentation, forward, 45 and 90 degree left external world views, and a map display. Control inputs are provided by high-fidelity analog controls (e.g., damped and self-centering yoke, high-performance throttle quadrant, gear, flap, and trim controls; and navigation radio frequency select). The simulation is based upon two commercially available flight simulation software packages, one designed as an instrument flight trainer and the other as a “game”-type flight simulation. The provisions of these packages are discussed highlighting their particular research capabilities as well as their limitations. The comparatively low cost and ease of assembly/integration allow multiple “standardized” systems to be distributed for cooperative interlaboratory studies. The approach appears to have utility for both research and training. Preliminary experimental results are reported as a validation of the utility of the system for research.
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Trukhanov, K. A. "The use of hydraulic communication channel in technical systems". Izvestiya MGTU MAMI 11, nr 2 (15.06.2017): 54–63. http://dx.doi.org/10.17816/2074-0530-66912.
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When developing technological systems, it becomes necessary to transmit information over significant distances without the use of traditional means of communication, because they can not be used, for example, in the field of geonavigation when drilling inclined / horizontal wells. One of the possible channels for transmitting information in this area is the hydraulic communication channel (HCC). Therefore, at present, the task of developing an effective method and approach for transmitting information on the HCC becomes urgent. The purpose of this work was to create a mathematical model of the HCC to provide practical recommendations when used in technology to assess the possibility of transmitting information on it without conducting costly field tests. The article presents a mathematical model of the HCC, which is a long hydroline, taking into account the boundary conditions at its input and output from it. The input boundary condition is represented by a piston pump with a crank-and-rod drive mechanism. The output boundary condition is represented by a throttle - a mechanical device capable of overlapping the pass channel in the hydrolysis line, thereby creating pressure pulses through which useful transmitted information is generated over the HCC. The obtained characteristic for the relative instantaneous feed Q is shown as a function of the angle φ of rotation of the pump shaft. A relation is given that establishes the relationship between the area of the opened throttle windows and the angle of rotation of its shaft. Two applied methods for encoding information in technological systems for information transmission are considered and a dependence for the attenuation of the signal amplitude during data transmission over the HCC is given. A mathematical simulation of the system with HCC and the described boundary conditions is performed. The form of the pressure pulse is obtained. Based on the results of the work, conclusions were drawn.
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Sazgar, Hadi, Shahram Azadi, Reza Kazemi i Ali Keymasi Khalaji. "Integrated longitudinal and lateral guidance of vehicles in critical high speed manoeuvres". Proceedings of the Institution of Mechanical Engineers, Part K: Journal of Multi-body Dynamics 233, nr 4 (15.05.2019): 994–1013. http://dx.doi.org/10.1177/1464419319847916.
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One of the most important and conventional manoeuvres, that is not easy to even skilled drivers, is the high-speed critical lane change on the highways. The main contribution of this study is the development of an integrated longitudinal and lateral guidance algorithm for these manoeuvres. This algorithm consists of two parts: the trajectory planning and the integrated control. In the first part, taking into account the position of the target vehicle for different accelerations, several trajectories are produced. Next, considering the dynamic capabilities of the vehicle, the most appropriate trajectory is selected. Since the proposed trajectory planning approach works algebraically, its computational cost is negligible, which is very valuable for practical implementations. In the second step, using a robust-integrated longitudinal–lateral controller, the control inputs are calculated and transmitted to the brakes, throttle and steering actuators. It should be noted that the trajectory planning and the integrated controller are based on the seven degrees of freedom model of the vehicle, and the nonlinear dynamics of the tyre and the dynamics of the brakes/throttle actuators are also taken into account. To assess the efficiency of the integrated longitudinal–lateral guidance algorithm, the full vehicle model is used in the CarSim–Simulink software. In order to have conditions closer to real applications, it is assumed that the yaw rate and the longitudinal and lateral accelerations of the vehicle are noisy, and the longitudinal and lateral velocities are predicted using the same signals. Obtained results for the critical collision avoidance manoeuvres confirm the effectiveness of the proposed planned trajectory and the good performance of the combined control method. In addition, the results indicate that the integrated control is robust against the variation of friction coefficient and unmodelled dynamics while maintaining the vehicle stability.
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Bozza, Fabio, Vincenzo De Bellis i Luigi Teodosio. "A numerical procedure for the calibration of a turbocharged spark-ignition variable valve actuation engine at part load". International Journal of Engine Research 18, nr 8 (24.10.2016): 810–23. http://dx.doi.org/10.1177/1468087416674653.
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Referring to spark-ignition engines, the downsizing, coupled to turbocharging and variable valve actuation systems are very common solutions to reduce the brake-specific fuel consumption at low-medium brake mean effective pressure. However, the adoption of such solutions increases the complexity of engine control and management because of the additional degrees of freedom, and hence results in a longer calibration time and higher experimental efforts. In this work, a twin-cylinder turbocharged variable valve actuation spark-ignition engine is numerically investigated by a one-dimensional model (GT-Power™). The considered engine is equipped with a fully flexible variable valve actuation system, realizing both a common full-lift strategy and a more advanced early intake valve closure strategy. Refined sub-models are used to describe turbulence and combustion processes. In the first stage, one-dimensional engine model is validated against the experimental data at full and part load. The validated model is then integrated in a multipurpose commercial optimizer (modeFRONTIER™) with the aim to identify the engine calibration that minimizes brake-specific fuel consumption at part load. In particular, the decision parameters of the optimization process are the early intake valve closure angle, the throttle valve opening, the turbocharger setting and the spark timing. Proper constraints are posed for intake pressure in order to limit the gas-dynamic noise radiated at the intake mouth. The adopted optimization approach shows the capability to reproduce with good accuracy the experimentally identified calibration. The latter corresponds to the numerically derived Pareto frontier in brake mean effective pressure–brake specific fuel consumption plane. The optimization also underlines the advantages of an engine calibration based on a combination of early intake valve closure strategy and intake throttling rather than a purely throttle-based calibration. The developed automatic procedure allows for a ‘virtual’ calibration of the considered engine on completely theoretical basis and proves to be very helpful in reducing the experimental costs and the engine time-to-market.
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Lin, Peng, Cong Wang i Min Wang. "Bifurcation Predication in Axial Compressors with Nonuniform Inflow via Deterministic Learning". International Journal of Bifurcation and Chaos 27, nr 10 (wrzesień 2017): 1750159. http://dx.doi.org/10.1142/s0218127417501590.
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The nonlinear dynamics of fluid instabilities such as rotating stall and surge in axial compressors are typically modeled as subcritical Hopf bifurcations with hysteresis. The bifurcation prediction provides an effective approach to avoid the occurrence of compressor’s instability. In this paper, based on a fluid dynamic model developed recently, a stall precursor detection approach employing deterministic learning (DL) is proposed for bifurcation predication in axial compressors with nonuniform inflow. The stall precursor near the bifurcation can be obtained as the throttle area parameter approaches its critical (or bifurcation) value. Firstly, the system dynamics underlying normal and stall precursor are locally approximated accurately through DL. The obtained knowledge of dynamics is stored in constant radial basis function (RBF) networks. Secondly, a bank of estimators is built up using the stored constant RBF networks to represent the learning normal and stall precursor patterns. By comparing each estimator with a test system, the average [Formula: see text] norms of the residuals are taken as the measure of the dynamical differences between the test system and the learning patterns. The occurrence of stall precursor as a bifurcation predication signal can be rapidly detected according to the smallest residual principle. Finally, simulation results are given to show the effectiveness of stall precursor detection approach.
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Alsuwian, Turki, Muhammad Sajid Iqbal, Arslan Ahmed Amin, Muhammad Bilal Qadir, Saleh Almasabi i Mohammed Jalalah. "A Comparative Study of Design of Active Fault-Tolerant Control System for Air–Fuel Ratio Control of Internal Combustion Engine Using Particle Swarm Optimization, Genetic Algorithm, and Nonlinear Regression-Based Observer Model". Applied Sciences 12, nr 15 (4.08.2022): 7841. http://dx.doi.org/10.3390/app12157841.
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In this article, three distinct strategies for designing an Active Fault-Tolerant Control System (AFTCS) for Air-Fuel Ratio (AFR) control of an Internal Combustion (IC) engine in a process plant to avoid engine shutdown, are presented. The proposed AFTCS employs a Genetic Algorithm (GA), Particle Swarm Optimization (PSO), and a Nonlinear Regression (NLR)-based observer model in the Fault Detection and Isolation (FDI) unit for analytical redundancy. A comparison between these three proposed techniques is carried out to determine the least expensive and most accurate approach. The results show that the nonlinear regression produces highly accurate results by consuming very low computational power, and its response time is also very low as compared to GA and PSO. The results obtained show that NLR requires 99.6% and 93.1% less computational time for throttle and MAP estimation, respectively, by reducing the estimation error to as low as 0.01. The simulation of the proposed system is carried out in the MATLAB/Simulink environment. The results prove the superior fault tolerance performance for sensor faults of the AFR control system, especially for the Manifold Absolute Pressure (MAP) sensor in terms of less oscillatory response as compared to that reported in existing literature.
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S.K., Sreekala, i Thirumalini S. "Effect of cage configurations on flow characteristics of globe valves". World Journal of Engineering 13, nr 1 (8.02.2016): 61–65. http://dx.doi.org/10.1108/wje-02-2016-007.
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Purpose Globe valves have good throttling ability, which permits its use in regulating flows. This paper aims to understand in detail the globe valve with different cage configurations and its impact on the flow characteristics that was carried out. Design/methodology/approach The computational study was carried out using FLUENT, a finite volume-based numerical code. Grid sensitivity tests were done and the results were validated experimentally. The effect of cage configuration on flow characteristics and valve coefficient was studied and optimised. Findings Valve coefficient was found to be dependent on cage configuration and reaches its maximum for the valve with triangular shaped aperture. Methodology to improve flow performance of a globe valve with highest valve coefficient is established. Originality/value Studies related with caged-type globe valves having different configurations are useful for improving their flow performance. In the present investigation, globe valves with different cage configurations and throttle positions are modeled to find out the valve coefficient, pressure and velocity contours inside and outside the cage and is validated with experimental results.
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Spender, J. C., i Jeroen Kraaijenbrink. "The Paradox of Strategizing: Embracing Managerial Agency without Throttling it". Journal of Business Strategy Finance and Management 04, nr 01 (8.06.2022): 12–37. http://dx.doi.org/10.12944/jbsfm.04.01.03.
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Strategizing implies making agentic choices in some middle ground between un-analyzable free will and agency-denying determinism. Paradoxically, neither view can capture the strategist’s situation or process. So how are strategy theorists approach agency? In our opening sections, we review the mainstream literature and find seven main arguments or tracks. Five, by improving methodological accuracy and reducing variance, effectively throttle or deny the strategist’s agency. The two other tracks offer agency an ontological or epistemological place in the analysis but underplay the synthetic nature of the strategist’s practice. In our final sections, we treat strategizing as handling the practice-based constraints to the strategist’s agency. A positivist approach makes little sense here for ex definition strategy supposes a finite option-space into which the strategist’s agency is ‘thrown’. Practitioners focus on their choices within this space rather than on the application of a generalized ‘theory of strategy’. There is little new here; but analyzing it means moving away from causal modeling and towards exploring the options remaining after all reasonable determining causes have been identified - leaving the strategist with the under-determined middle ground s/he ‘synthesizes’ from incommensurable theories and empirically justified heuristics. Concluding, we propose a novel track of theorizing for those strategists seeking to engage their agentic capabilities rather than theorizing about agency as a component of a rigorous academic model.
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Franchek, Matthew A., Patrick J. Buehler i Imad Makki. "Intake Air Path Diagnostics for Internal Combustion Engines". Journal of Dynamic Systems, Measurement, and Control 129, nr 1 (29.05.2006): 32–40. http://dx.doi.org/10.1115/1.2397150.
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Presented is the detection, isolation, and estimation of faults that occur in the intake air path of internal combustion engines during steady state operation. The proposed diagnostic approach is based on a static air path model, which is adapted online such that the model output matches the measured output during steady state conditions. The resulting changes in the model coefficients create a vector whose magnitude and direction are used for fault detection and isolation. Fault estimation is realized by analyzing the residual between the actual sensor measurement and the output of the original (i.e., healthy) model. To identify the structure of the steady state air path model a process called system probing is developed. The proposed diagnostics algorithm is experimentally validated on the intake air path of a Ford 4.6L V-8 engine. The specific faults to be identified include two of the most problematic faults that degrade the performance of transient fueling controllers: bias in the mass air flow sensor and a leak in the intake manifold. The selected model inputs include throttle position and engine speed, and the output is the mass air flow sensor measurement.
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Krepelka, Michal, i Jiri Vrany. "Synthesizing Vehicle Speed-Related Features with Neural Networks". Vehicles 5, nr 3 (26.06.2023): 732–43. http://dx.doi.org/10.3390/vehicles5030040.
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In today’s automotive industry, digital technology trends such as Big Data, Digital Twin, and Hardware-in-the-loop simulations using synthetic data offer opportunities that have the potential to transform the entire industry towards being more software-oriented and thus more effective and environmentally friendly. In this paper, we propose generative models to synthesize car features related to vehicle speed: brake pressure, percentage of the pressed throttle pedal, engaged gear, and engine RPM. Synthetic data are essential to digitize Hardware-in-the-loop integration testing of the vehicle’s dashboard, navigation, or infotainment and for Digital Twin simulations. We trained models based on Multilayer Perceptron and bidirectional Long-Short Term Memory neural network for each feature. These models were evaluated on a real-world dataset and demonstrated sufficient accuracy in predicting the desired features. Combining our current research with previous work on generating a speed profile for an arbitrary trip, where Open Street Map data and elevation data are available, allows us to digitally drive this trip. At the time of writing, we are unaware of any similar data-driven approach for generating desired speed-related features.
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Yin, Shutong, Chunlin Yang, Ibna Kawsar, Haifeng Du i Yongjun Pan. "Longitudinal Predictive Control for Vehicle-Following Collision Avoidance in Autonomous Driving Considering Distance and Acceleration Compensation". Sensors 22, nr 19 (28.09.2022): 7395. http://dx.doi.org/10.3390/s22197395.
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In response to the widespread adoption of vehicle-following systems in autonomous applications, the demand for collision warning to enable safer functionalities is increasing. This study provides an approach for automated vehicle guidance to follow the preceding vehicles longitudinally and puts emphasis on the performance of collision avoidance. The safety distance model is established, which contains a distance compensation algorithm to deal with the special case on curved roads. By introducing the algorithm of velocity and distance prediction, the collision risks are detected and measured in real time. The objective function is established based on optimal control theory to solve the desired following acceleration. The control system designed with the method of proportion integration differentiation combines throttle percentage and brake pressure as outputs to compensate acceleration. In the Carsim and Simulink co-simulation platform, the control system for longitudinal collision avoidance is simulated and analysed for four typical working conditions: the preceding vehicle drives at a constant speed on straight and curved roads, while the preceding vehicle drives at various speeds on straight and curved roads. The results validate the feasibility and effectiveness of the proposed method, which can be used for the longitudinal control of vehicle-following active collision avoidance.
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Kumar, M. Naveen, Vishal Jagota i Mohammad Shabaz. "Retrospection of the Optimization Model for Designing the Power Train of a Formula Student Race Car". Scientific Programming 2021 (29.11.2021): 1–9. http://dx.doi.org/10.1155/2021/9465702.
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This article describes the power train design specifics in Formula student race vehicles used in the famed SAE India championship. To facilitate the physical validation of the design of the power train system of a formula student race car category vehicle engine of 610 cc displacement bike engine (KTM 390 model), a detailed design has been proposed with an approach of easing manufacturing and assembly along with full-scale prototype manufacturing. Many procedures must be followed while selecting a power train, such as engine displacement, fuel type, cooling type, throttle actuation, and creating the gear system to obtain the needed power and torque under various loading situations. Keeping the rules in mind, a well-suited engine was selected for the race track and transmission train was selected which gives the maximum performance. Based on the requirement, a power train was designed with all considerations we need to follow. Aside from torque and power, we designed an air intake with fuel efficiency in mind. Wireless sensors and cloud computing were used to monitor transmission characteristics such as transmission temperature management and vibration. The current study describes the design of an air intake manifold with a maximum restrictor diameter of 20 mm.
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Schreiber, T., A. Schwartz i D. Muller. "Towards an intelligent HVAC system automation using Reinforcement Learning". Journal of Physics: Conference Series 2042, nr 1 (1.11.2021): 012028. http://dx.doi.org/10.1088/1742-6596/2042/1/012028.
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Abstract HVAC systems are among the biggest energy consumers in buildings and therefore in the focus of optimal control research. In practice, rule-based control and PID controllers are typically used and implemented at the beginning of the building operation. Since this approach neither guarantees optimal or even good control, optimal control algorithms (which can be predictive and adaptive) are in the focus of research. The problem with most of the approaches is that a model of the system is often needed which comes with high engineering efforts. Further, the required computing power can quickly exceed the capacities, even in modern buildings. Therefore, in this paper we investigate the application of a state-of-the-art Reinforcement Learning (RL) algorithm, as a self-calibrating valve controller for two water-air heat exchangers of a real-world air handling unit. We choose a generic problem formulation to pre-train the algorithm with a simulation of an admixing heater and use it to control an injection heater and a throttle cooler. Our results show that after only 70 hours, the control quality significantly increases. Therefore, it seems evident that with pre-trained RL algorithms, a self-improving HVAC automation can be realized with little hardware requirements and without extensive modelling of the system dynamics.
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Yadav, Arun K., i Janusz Szpytko. "Safety problems in vehicles with adaptive cruise control system". Journal of KONBiN 42, nr 1 (1.06.2017): 389–98. http://dx.doi.org/10.1515/jok-2017-0035.
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Abstract In today’s world automotive industries are still putting efforts towards more autonomous vehicles (AVs). The main concern of introducing the autonomous technology is safety of driver. According to a survey 90% of accidents happen due to mistake of driver. The adaptive cruise control system (ACC) is a system which combines cruise control with a collision avoidance system. The ACC system is based on laser and radar technologies. This system is capable of controlling the velocity of vehicle automatically to match the velocity of car, bus or truck in front of vehicle. If the lead vehicle gets slow down or accelerate, than ACC system automatically matches that velocity. The proposed paper is focusing on more accurate methods of detecting the preceding vehicle by using a radar and lidar sensors by considering the vehicle side slip and by controlling the distance between two vehicles. By using this approach i.e. logic for calculation of former vehicle distance and controlling the throttle valve of ACC equipped vehicle, an improvement in driving stability was achieved. The own contribution results with fuel efficient driving and with more safer and reliable driving system, but still some improvements are going on to make it more safe and reliable.
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Huch, Sebastian, Aybike Ongel, Johannes Betz i Markus Lienkamp. "Multi-Task End-to-End Self-Driving Architecture for CAV Platoons". Sensors 21, nr 4 (3.02.2021): 1039. http://dx.doi.org/10.3390/s21041039.
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Connected and autonomous vehicles (CAVs) could reduce emissions, increase road safety, and enhance ride comfort. Multiple CAVs can form a CAV platoon with a close inter-vehicle distance, which can further improve energy efficiency, save space, and reduce travel time. To date, there have been few detailed studies of self-driving algorithms for CAV platoons in urban areas. In this paper, we therefore propose a self-driving architecture combining the sensing, planning, and control for CAV platoons in an end-to-end fashion. Our multi-task model can switch between two tasks to drive either the leading or following vehicle in the platoon. The architecture is based on an end-to-end deep learning approach and predicts the control commands, i.e., steering and throttle/brake, with a single neural network. The inputs for this network are images from a front-facing camera, enhanced by information transmitted via vehicle-to-vehicle (V2V) communication. The model is trained with data captured in a simulated urban environment with dynamic traffic. We compare our approach with different concepts used in the state-of-the-art end-to-end self-driving research, such as the implementation of recurrent neural networks or transfer learning. Experiments in the simulation were conducted to test the model in different urban environments. A CAV platoon consisting of two vehicles, each controlled by an instance of the network, completed on average 67% of the predefined point-to-point routes in the training environment and 40% in a never-seen-before environment. Using V2V communication, our approach eliminates casual confusion for the following vehicle, which is a known limitation of end-to-end self-driving.
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Murat Otkur. "Altitude Performance and Fuel Consumption Modelling of Aircraft Piston Engine Rotax 912 S/ULS". Journal of Advanced Research in Applied Sciences and Engineering Technology 23, nr 1 (14.05.2021): 18–25. http://dx.doi.org/10.37934/araset.23.1.1825.
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Rotax 912 spark-ignition (SI) naturally aspirated aircraft piston engine is one of the most popular prime movers for the ultra-light weight aircrafts used for short and moderate range flights. SI engines operate at stoichiometric combustion and at high altitude conditions atmospheric pressure is lower than sea level reducing mass of air intake to the engine. At these conditions engine power degrades significantly from sea level, affecting flight parameters such as range and endurance. In order to optimize these parameters, engine power modelling is of vital importance. Within the scope of this study, a thermodynamic SI engine model with performance parameters (break torque and power) and fuel consumption estimation developed in MATLAB/Simulink software. Model tuning is realised using data extracted from Rotax engine operating manual at sea level and high altitude conditions. Model inputs are set as altitude, throttle lever and engine speed. Pressure drop at the intake port is modelled as a function of mass air flow using engine operating manual pressure data at various engine speed points. Mass air flow is determined via employing a volumetric efficiency map based on intake port pressure and engine speed inputs, calibrated using engine operating manual fuel data considering stoichiometric combustion. Compression and expansion strokes area modelled as isentropic events and combustion is modelled as constant volume heat input at top dead centre (TDC). However a combustion efficiency map based on engine speed and fuel flow is employed for the heat input in order to tune the work output of the engine and heat loss to the coolant and exhaust. Pumping loss is calculated based on friction mean effective pressure data. Introduced approach provides high accuracy performance and fuel consumption modelling based on engine operating manual data and can be used for flight parameters optimization studies.
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Washington, Simon, Jean Wolf i Randall Guensler. "Binary Recursive Partitioning Method for Modeling Hot-Stabilized Emissions From Motor Vehicles". Transportation Research Record: Journal of the Transportation Research Board 1587, nr 1 (styczeń 1997): 96–105. http://dx.doi.org/10.3141/1587-11.
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An alternative statistical modeling approach, hierarchical tree-based regression (HTBR), is presented for developing modal correction factors for hydrocarbon (HC) emissions from motor vehicles. The term modal refers to operating modes of vehicle activity such as cruise, idle, deceleration, and acceleration. Explanation of the statistical theory is provided, followed by a presentation of specific modeling results for HCs. The modeling results are based on 4,800 vehicle emissions tests representing 29 laboratory testing cycles. HTBR methods are indicated to overcome statistical difficulties that are problematic for classical ordinary least-squares (OLS) regression, a commonly applied statistical technique for analyzing emissions data. HTBR methods are more adept at treating interactions and monotonic transformations on independent variables, better at handling categorical independent variables with more than two levels, not adversely affected by multicollinearity, and good at capturing nonadditive behavior across the range of independent variables. Unfortunately, HTBR theory is less well developed than OLS regression theory, and statistical parameter properties, such as efficiency, unbiasedness, and consistency, need further development. The HTBR modeling results for HCs are insightful. Hydrocarbon emissions from normal-emitting motor vehicles are most sensitive to changes in power (instantaneous speed2 ƃ acceleration) requirements of a given driving sequence, while high-emitting vehicles are sensitive to both the amount of idle activity and positive kinetic energy (instantaneous speed ƃ acceleration) in a given driving sequence. Vehicle model year, engine size (cubic centimeters of displacement), curbside weight, and fuel delivery type (fuel injected, throttle body injected, carbureted), also were indicated to influence emission rates. Finally, high- and normal-emitting vehicles are sensitive to different operational and vehicle specific factors.
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Toma, Adina Cristina, Grigore Cican i Daniel-Eugeniu Crunteanu. "Enhancing Air Traffic Management and Reducing Noise Impact: A Novel Approach Integrating Băneasa Airport with Otopeni RO Airport". Applied Sciences 13, nr 16 (10.08.2023): 9139. http://dx.doi.org/10.3390/app13169139.
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Over the years, Bucharest’s Henri Coandă International Airport has registered a constant and high increase in air traffic, in terms of both passengers and aircraft movements. This paper presents a traffic diversion solution for the Otopeni RO airport, which aims to alleviate air traffic congestion by redirecting a proportion of the planes to the nearby airport at Băneasa. The primary challenge faced by diversion to Băneasa Airport is the proximity of residential areas to the runway at distances of less than 300 m, resulting in significant noise pollution issues. At Otopeni Airport, the main operators use aircraft equipped with CFM 56 turbo engines; therefore, this study begins with an evaluation of the noise directivity of a CFM aircraft engine via measurement. The data thus collected enabled the identification of the dominant frequencies in the acoustic spectrum of the engine noise. A resonant screen solution has been proposed as a solution for Băneasa Airport, emphasizing the importance of implementing solutions to address the noise pollution faced by those living near Băneasa Airport, due to its proximity to the residential area. Various configurations of perforated metal sheets with different perforation patterns were compared to the test performance of solid sheets to optimize noise absorption. Using the impedance tube tests to achieve the highest absorption coefficient, it was determined that the optimal distance between the perforated metal sheets and the resonant screen was 30 mm. Based on the CFM 56 turbo engine noise directivity and the impedance tube tests, a multitude of numerical simulations were conducted using the IMMI software (IMMI 2011). The simulations were performed for two scenarios with and without an acoustic barrier, accounting for the typical configuration of two engines on an aircraft. The results indicate a reduction of 15 dBA with the implementation of a 4-m-high acoustic barrier, in the case of a CFM 56 engine operating at full throttle while the aircraft is on the ground. Through numerical simulations, the optimized resonant screen demonstrated its potential to significantly reduce noise levels, thereby enhancing the overall acoustic environment and quality of life for the communities surrounding Băneasa Airport. The identified findings could serve as a basis for further research and the implementation of innovative solutions to manage air traffic and reduce the impact of aircraft noise in surrounding areas.
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Гребеников, Александр Григорьевич, Виктор Павлович Люшнин, Татьяна Борисовна Богачева i Леонид Анатольевич Мальков. "ТЕХНОЛОГІЧНЕ ОБЛАДНАННЯ НА ПОВІТРЯНИХ ПОДУШКАХ КОВЗАННЯ - ЗАСТОСУВАННЯ В ЛІТАКОБУДУВАННІ. РОЗРАХУНОК ПАРАМЕТРІВ". Open Information and Computer Integrated Technologies, nr 86 (14.02.2020): 91–107. http://dx.doi.org/10.32620/oikit.2019.86.06.
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The technological equipment under consideration relates to air-cushioned out-door vehicles operating from the workshop pneumatic network. Their designs are based on the modular principle. A typical design of such equipment equipped with inflatable balloon fences is presented. The effectiveness of their use in aircraft construction is shown. When performing interoperational movements, they provide savings in production space due to the compact placement of aircraft in assembly shops. When performing mounting and docking operations, the proposed equipment does not require accurate combination of mating units and simplifies the process of docking heavy units. The equipment also allows for cyclic ground tests of a rotary wing of an aircraft with loads close to flight. This eliminates possible emergency situations during flight tests and ensures the safety of expensive products. When performing loading and unloading operations, the use of air cushions allows to reduce the weight of loading equipment, as well as reduce the time and cost of these operations. Most researchers consider the flow to be viscous and laminar due to small flow gaps be-tween the balloon guard and the floor supporting surface. A new approach is pro-posed here. It is based on a turbulent regime of outflow from an air cushion. This is confirmed by replacing the real air path with an equivalent circular section. As a result, the configuration of the outlet channel is transformed into a short confuser diffuser nozzle with a small length along the flow. And such resistances are considered turbulent. As the first turbulent throttle acts as an air flow regulator at the en-trance to the support. Proceeding from this, calculation methods are proposed that allow one to determine expendable, energy, and specific indicators of both individual modules on air cushions and systems based on them. The information necessary for the designer is given to solve current problems in aircraft construction and other are-as of technology.
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Huang, Junfeng, Jianbing Gao, Ce Yang, Guohong Tian i Chaochen Ma. "The Effect of Ignition Timing on the Emission and Combustion Characteristics for a Hydrogen-Fuelled ORP Engine at Lean-Burn Conditions". Processes 10, nr 8 (5.08.2022): 1534. http://dx.doi.org/10.3390/pr10081534.
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The application of hydrogen fuel in ORP engines makes the engine power density much higher than that of a reciprocating engine. This paper investigated the impacts of combustion characteristics, energy loss, and NOx emissions of a hydrogen-fuelled ORP engine by ignition timing over various equivalence ratios using a simulation approach based on FLUENT code without considering experiments. The simulations were conducted under the equivalence ratio of 0.5~0.9 and ignition timing of −20.8~8.3 °CA before top dead centre (TDC). The engine was operated under 1000 RPM and wide-open throttle condition which was around the maximum engine torque. The results indicated that significant early ignition of the ORP engine restrained the flame development in combustion chambers due to the special relative positions of ignition systems to combustion chambers. In-cylinder pressure evolutions were insensitive to early ignition. The start of combustion was the earliest over the ignition timing of −17.3 °CA for individual equivalence ratios; the correlations of the combustion durations and equivalence ratios were dependent on the ignition timing. Combustion durations were less sensitive to equivalence ratios in the ignition timing range of −14.2~−11.1 °CA before TDC. The minimum and maximum heat release rates were 15 J·(°CA)−1 and 22 J·(°CA)−1 over the equivalence ratios of 0.5 and 0.9, respectively. Indicated thermal efficiency was higher than 41% for early ignition scenarios, and it was significantly affected by late ignition. Energy loss by cylinder walls and exhaust was in the range of 10%~16% and 42%~58% of the total fuel energy, respectively. The impacts of equivalence ratios on NOx emission factors were affected by ignition timing.
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Xiong, Shaoping, Gabriel Wilfong i John Lumkes. "Components Sizing and Performance Analysis of Hydro-Mechanical Power Split Transmission Applied to a Wheel Loader". Energies 12, nr 9 (28.04.2019): 1613. http://dx.doi.org/10.3390/en12091613.
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The powertrain efficiency deeply affects the performance of off-road vehicles like wheel loaders in terms of fuel economy, load capability, smooth control, etc. The hydrostatic transmission (HST) systems have been widely adopted in off-road vehicles for providing large power density and continuous variable control, yet using relatively low efficiency hydraulic components. This paper presents a hydrostatic-mechanical power split transmission (PST) solution for a 10-ton wheel loader for improving the fuel economy of a wheel loader. A directly-engine-coupled HST solution for the same wheel loader is also presented for comparison. This work introduced a sizing approach for both PST and HST, which helps to make proper selections of key powertrain components. Furthermore, this work also presented a multi-domain modeling approach for the powertrain of a wheel loader, that integrates the modeling of internal combustion (IC) engine, hydraulic systems, mechanical transmission, vehicle(wheel) dynamics, and relevant control systems. In this modeling, an engine torque evaluation method with a throttle position control system was developed to describe the engine dynamics; a method to express the hydraulic loss of the axial piston hydraulic pump/motor was developed for modeling the hydraulic transmission; and a vehicle velocity control system was developed based on altering the displacement of a hydraulic unit. Two powertrain models were developed, respectively, for the PST and HST systems of a wheel loader using MATLAB/Simulink. The simulation on a predefined wheel loader drive cycle was conducted on both powertrain models to evaluate and compare the performance of wheel loader using different systems, including vehicle velocity, hydraulic displacement control, hydraulic torque, powertrain efficiency, and engine power consumption. The simulation results indicate that the vehicle velocity controller developed functions well for both the PST and HST systems; a wheel loader using the proposed PST solution can overall save about 8% energy consumption compared using an HST solution in one drive cycle. The sizing method and simulation models developed in this work should facilitate the development of the powertrains for wheel loaders and other wheeled heavy vehicles.
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Chen, Gang, i Wei-gong Zhang. "Design of prototype simulation system for driving performance of electromagnetic unmanned robot applied to automotive test". Industrial Robot: An International Journal 42, nr 1 (19.01.2015): 74–82. http://dx.doi.org/10.1108/ir-06-2014-0353.
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Purpose – The purpose of this paper is to present a prototype simulation system for driving performance of an electromagnetic unmanned robot applied to automotive test (URAT) to solve that it is difficult and dangerous to online debug control program and to quickly obtain test vehicle dynamic performance. Design/methodology/approach – The driving performance of the electromagnetic URAT can be evaluated by the prototype simulation system. The system can simulate various driving conditions of test vehicles. An improved vehicle longitudinal dynamics model matching to the electromagnetic URAT is established. The proposed model has good real-time, and it is easy to implement. The displacement of throttle mechanical leg, brake mechanical leg, clutch mechanical leg and shift mechanical arm is used for the system input. Test vehicle speed and engine speed are used for the system output, and they are obtained by the computation of the established vehicle longitudinal dynamics model. Findings – Driving conditions simulation test and vehicle emission test are performed using a Ford Focus car. Simulation and experiment results show that the proposed prototype simulation system in the paper can simulate the driving conditions of actual vehicles, and the performance that electromagnetic URAT drives an actual vehicle is evaluated by the simulation system. Research limitations/implications – Future research will focus on improving the real time of the proposed simulation system. Practical implications – The autonomous driving performance of electromagnetic URAT can be evaluated by the proposed prototype simulation system. Originality/value – A prototype simulation system for driving performance of an electromagnetic URAT based on an improved vehicle longitudinal dynamics model is proposed in this paper, so that it can solve the difficulty and danger of online debugging control program, quickly obtaining the test vehicle performance.
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Veza, Ibham, Ling Chee Huat, Mohd Azman Abas, Muhammad Idris, Martin Spraggon i Safarudin G. Herawan. "Effects of Pre-Turbocharger Turbine Water Injection on the Sustainable Performance of Spark Ignition Engine". Sustainability 15, nr 5 (3.03.2023): 4559. http://dx.doi.org/10.3390/su15054559.
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Water injection strategy is considered a promising technique to improve the performance of boosted engine and reduce the NOx emission via the latent heat of water vaporization. Numerous research on water injection has been conducted on in-cylinder and intake port water injection. However, the water injection focusing on the spark ignition (SI) engine exhaust system is still lacking. This study proposed a pre-turbocharger turbine water injection (PTWI) concept to reduce the turbine inlet temperature. This was done so that the stoichiometric engine operation could be achieved at a medium–high load and engine speed without resorting to a fuel enrichment strategy to reduce the exhaust gas temperature. This study aims to investigate the effect of injecting water into the exhaust gas at the pre-turbine of a turbocharged spark ignition engine. This study experimented on a 1.3-L 4-cylinder turbocharged engine to collect engine data for computational fluid dynamics (CFD) baseline model validation. A one-dimensional engine model was then developed based on the 1.6-L 4-cylinder turbocharged engine experiment using AVL BOOST software. The CFD model was used to investigate the effects of water injection pressure, pipe diameter, and water injector location. The CFD results showed that a 50 mm connecting pipe with 4 bar of injection pressure gives the largest reduction in exhaust temperature. The CFD results were then applied to the one-dimensional engine model. The engine model simulation results showed that the fuel consumption could be reduced up to 13% at 4000 rpm during wide-open throttle and 75% engine load. The PTWI is a new approach, but this study has proved the potential of using water injection at the pre-turbine turbocharger to reduce the fuel consumption of a turbocharged SI engine.
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Sanchugov, Valeriy, i Pavel Rekadze. "New Method to Determine the Dynamic Fluid Flow Rate at the Gear Pump Outlet". Energies 15, nr 9 (9.05.2022): 3451. http://dx.doi.org/10.3390/en15093451.
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External gear pumps are among the most popular fluid power positive displacement pumps; however, they often suffer from excessive flow pulsation transmitted to the downstream circuit. To meet the increasing demand of quiet operation for modern fluid power systems, it is necessary to give a physically sound method of analyzing the operation of a volumetric pump. The analysis of the basic approach used by the majority of researchers for calculating the flow rate of a gear pump by E.M. Yudin is presented. The article presents a new method for analyzing the operation of volumetric pumps. The method is suitable for the pumps whose dynamic characteristics should be considered according to the model of an equivalent source of flow fluctuations by V.P. Shorin. The method is based on wave theory, the method of hydrodynamic analogies and the impedance method, where the pump is considered according to the model in lumped parameters. The method consists in determining the pressure pulsations at the pump output in bench systems with known dynamic characteristics and recalculating the pump flow rate in pulsations. Computational dynamic models of bench systems in lumped parameters are proposed for subsequent use in dynamic tests of pumps in the form of equivalent sources of fluid flow fluctuations. We give recommendations for the formation of test bench systems with a throttle, a cavity and a pipeline at the pump output. Using the example of an external gear pump with a working volume of 14 cm3/rev, the implementation of the proposed method is considered. The pump’s own pulsation characteristic of the flow rate in a bench system with an “infinitely long” pipeline along two harmonic components of the spectrum is determined, and a test of the method based on the method of determining the instantaneous flow rate by R.N. Starobinskiy is proposed. It is shown that, according to the proposed method and the method of R.N. Starobinskiy, the divergence of the amplitudes of flow pulsations does not exceed (5–10)%. The high degree of coincidence of the results confirms that the external gear pump in question should be considered according to the equivalent source of flow fluctuations model.
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Mustaffa, Ahmad Fikri, i Vasudevan Kanjirakkad. "Stall margin improvement in a low-speed axial compressor rotor using a blockage-optimised single circumferential casing groove". Journal of the Global Power and Propulsion Society 5 (3.05.2021): 79–89. http://dx.doi.org/10.33737/jgpps/133912.
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The stall margin of tip-critical axial compressors can be improved by using circumferential casing grooves. From previous studies, in the literature, the stall margin improvement due to the casing grooves can be attributed to the reduction of the near casing blockage. The pressure rise across the compressor as the compressor is throttled intensifies the tip leakage flow. This results in a stronger tip leakage vortex that is thought to be the main source of the blockage. In this paper, the near casing blockage due to the tip region aerodynamics in a low-speed axial compressor rotor is numerically studied and quantified using a mass flow-based blockage parameter. The peak blockage location at the last stable operating point for a rotor with smooth casing is found to be at about 10% of the tip chord aft of the tip leading edge. Based on this information, an optimised single casing groove design that minimises the peak blockage is found using a surrogate-based optimisation approach. The implementation of the optimised groove is shown to produce a stall margin improvement of about 5%.
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Song, Peng, Shengyuan Wang i Jinju Sun. "Numerical Investigation and Performance Enhancement by Means of Geometric Sensitivity Analysis and Parametric Tuning of a Radial-Outflow High-Pressure Oil–Gas Turbine". Energies 15, nr 22 (16.11.2022): 8576. http://dx.doi.org/10.3390/en15228576.
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The pressure at the natural gas wellhead typically ranges from tens to hundreds of atmospheres. Traditionally, the wellhead pressure must be throttled into a low level to satisfy the requirement of gathering pipelines, in which a large amount of pressure energy is wasted. The high-pressure oil–gas turbine is a promising approach to convert the wellhead pressure energy into shaft power or electricity. In this paper, a numerical investigation is conducted on a radial-outflow high-pressure oil–gas turbine utilized in a wellhead pressure power generation system. Using the self-defined real oil–gas physical properties and Computational Fluid Dynamics (CFD), the internal flow and performance of the high-pressure oil–gas turbine under complex operating conditions are investigated. To improve the turbine flow and performance, a Latin Hypercube Sampling-based parametric tuning is performed on the stator and rotor blade geometries. The application of such an approach effectively adjusts the flow matching and eliminates the flow separation, by which the turbine performance is significantly enhanced.
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Siddiqui, Shadab, Manuj Darbari i Diwakar Yagyasen. "Enhancing the Capability of Load Management Techniques in Cloud Using H_FAC Algorithm Optimization". International Journal of e-Collaboration 16, nr 2 (kwiecień 2020): 65–81. http://dx.doi.org/10.4018/ijec.2020040105.
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Load balancing is a major research discipline in Cloud computing. The services are provided to users on pay as you go manner. Although a lot of algorithms have been proposed for load balancing, but performance is still an issue. The authors have proposed a new hybrid algorithm H_FAC to optimize the performance in cloud computing. The hybrid technique combines cuckoo search along with the Firefly algorithm of swarm intelligence. The benefit of using hybridization technique is that strength of one algorithm will overcome the shortcomings of other algorithms. Blockchain ID based Signature technique is used to ensure the authenticity of cloud service provider. The experimental results of H_FAC minimize the standard deviation, execution time significantly and improved throughput thereby optimizing the performance. The hybrid algorithm is also compared with other algorithms like ant colony optimization, artificial bee colony, round robin, FCFS and modified throttled. This approach helps the users to get the resources from authentic resource providers with a reduced execution time.