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38th International Symposium on Combustion, 2021

作者： Kim, Doohyun Violi, Angela Department of Mechanical and System Design Engineering Hongik University 94 Wausan-ro Mapo-gu Seoul Korea Republic of Departments of Mechanical Engineering Chemical Engineering Biophysics Program University of Michigan Ann Arbor MI United States

Fuel surrogates are mixtures of simple compounds that emulate the combustion characteristics of more complex fuels, with the primary objective to enable detailed combustion modeling of very complex real fuels. Current efforts in surrogate development aim to optimize the compositions of pure hydrocarbons to emulate multiple combustion related properties. In doing so, weights are assigned when defining optimization problem to reflect the importance of each property. In this study, the impact of surrogate component selection and weight assignment on surrogate formulations was quantitatively investigated by analyzing their sensitivities during the surrogate optimization. Using experimental data of a reference jet fuel as target, a study was designed using a surrogate optimizer that imposes orthogonal perturbations on the surrogate components and weights, and their effect on the optimized surrogate mixtures was analyzed. Results from 3600 cases revealed that perturbations of surrogate components, rather than weights, induce far greater variability in the optimized composition and target property agreement. While the derived cetane number (DCN) agreement showed a greater variability from the weight perturbation, the main reason for such high sensitivity was due to the wide range of values for pure component DCN of the individual components, which was also a result of the surrogate component selection. The results also demonstrated that the selection of surrogate components nearly predefines the overall shape of the distillation curves regardless of the weight values. This study quantitatively supports the idea that appropriate selection of surrogate components that capture the physical and chemical characteristics of actual constituents of target fuel will increase the possibility of successful surrogate formulation and will mitigate the impact from arbitrary weight assignment.

关键词： Fuel additives

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Numerical Investigation of the Hydrodynamic Performance of a Pitch-Type Wave Energy Converter on the Basis of Weakly and Fully Nonlinear Models

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SSRN 2023年

作者： Poguluri, Sunny Kumar Kim, Dongeun Cho, Il-Hyoung Kim, Sangho Bae, Yoon Hyeok Mechanical and System Design Engineering Hongik University Korea Republic of Multidisciplinary Graduate School Program for Wind Energy Jeju National University Korea Republic of Department of Ocean System Engineering Jeju National University Korea Republic of Korea Republic of

Pitch-type wave energy converters (e.g., Salter’s duck-type wave energy converter [WEC] rotor) have been proven to work effectively in 2D. However, only a few studies have investigated the 3D nonlinear effects. Large motions, wave breaking, slamming, and 3D crossflows are factors that cannot be overlooked and have a direct effect on the absorbed power, thereby necessitating the use of nonlinear numerical models. This study addresses the interaction between the wave and WEC rotor by using a weakly nonlinear model (based on potential flow theory) and a fully nonlinear model (based on computational fluid dynamics). The weakly nonlinear model is formulated by incorporating the nonlinear restoring moment and Coulomb type of power take-off (PTO) load torque. It is compared with fully nonlinear simulations and validated using experimental results. Results show that in regular waves with a wave steepness (H/λ) of 0.03, the weakly nonlinear model agrees well with the fully nonlinear model, except in the long range of one-way PTO load torque where deviations are observed. These differences are amplified with the increase in wave steepness and PTO load torque due to the strong nonlinear effects, thereby limiting the applicability of the weakly nonlinear model to H/λ = 0.03. © 2023, The Authors. All rights reserved.

关键词： Computational fluid dynamics

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optimization of Configuration Hybrid Power Generation system at Oil Refinery

optimization of Configuration Hybrid Power Generation System...

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International Conference on High Voltage engineering and Power systems (ICHVEPS)

作者： Muhamad Apriyudi Syafputra Joko Waluyo Roni Imawan Magister Program in System Engineering Universitas Gadjah Mada Yogyakarta Indonesia Department of Mechanical and Industrial Engineering Universitas Gadjah Mada Yogyakarta Indonesia Department of Electrical Engineering Universitas Gadjah Mada Yogyakarta Indonesia

The oil refinery industry has a potential emission reduction by combining its fossil fuel with Renewable Energy usage. One alternative to reduce carbon emissions is the hybrid power system using solar panels for electricity generation. This research will observe the optimum scenario for utilizing a hybrid power system. The research subject is observed refinery facilities that will be built in Indonesia, where the electricity source used formerly comes from fossils. The monitored parameters are Cost of Energy (COE) and carbon emission. optimization involves three scenarios involving basic and hybrid configurations. The basic scenario is the initial configuration of the electricity supply with power source from the generator and PLN (national’s utility). The first scenario is a hybrid power plant utilizing the roofs of existing buildings in the refinery area. The second is a hybrid power plant with a battery to supply electricity at night, at the capacity of renewable energy (RE) of 20% and 40%. Compared to the basic scenario, scenario 1 increases COE by 0.17% and reduces carbon emission at 0.3% compared to the basic scenario. Scenario 2 with 20% and 40% of renewable energy are obtained at COE of 4.7% and 44.3%, while reducing emissions occurred at 38% and 52.7%, respectively. The scenario of a hybrid power system with a 20% renewable energy is the optimal result compared to the other scenarios.

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Guest Editorial: Special Issue on Technology Trends in Control, Robotics and systems - For the 30th Anniversary of the Institute of Control, Robotics and systems -

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Journal of Institute of Control, Robotics and systems 2024年第4期30卷 295-295页

作者： Ko, Nak Yong Kang, Taesam Song, Jin Woo Lim, Myo Taeg Jo, Kang-Hyun Department of Electronic Engineering Interdisciplinary Program in IT-Bio Convergence System Chosun University Korea Republic of Department of Mechanical and Aerospace Engineering Konkuk University Korea Republic of Department of Intelligent Mechatronics Engineering Sejong University Korea Republic of School of Electrical Engineering Korea University Korea Republic of Department of Electrical Electronic and Computer Engineering University of Ulsan Korea Republic of

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Negative Stiffness Mechanism on an Asymmetric Wave Energy Converter by Using a Weakly Nonlinear Potential Model

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SSRN 2023年

作者： Poguluri, Sunny Kumar Kim, Dongeun Bae, Yoon Hyeok Mechanical and System Design Engineering Hongik University Seoul Korea Republic of Multidisciplinary Graduate School program for Wind Energy Jeju National University Jeju Korea Republic of

Salter’s duck, an asymmetrical wave energy converter (WEC) device, showed high efficiency in extracting energy from 2D regular waves in the past;yet, challenges remain for fluctuating wave conditions. These can potentially be addressed by adopting a negative stiffness mechanism (NSM) in WEC devices to enhance system efficiency, even in highly nonlinear and steep 3D waves. A weakly nonlinear model that incorporated a nonlinear restoring moment and NSM into the linear formulations and was applied to an asymmetric WEC using a time domain potential flow model was developed. The model was initially validated by comparing it with published experimental and numerical computational fluid dynamics results. The current results were in good agreement with the published results. It was found that the energy extraction increased in the range of 6% to 17% during the evaluation of the effectiveness of the NSM in regular waves. Under irregular wave conditions, specifically at the design wave conditions for the selected test site, the energy extraction increased by 2.4%, with annual energy production increments of approximately 0.8 MWh. The findings highlight the potential of NSM in enhancing the performance of asymmetric WEC devices, indicating more efficient energy extraction under various wave conditions. © 2023, The Authors. All rights reserved.

关键词： Computational fluid dynamics

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Model Predictive Control of a Hybrid VA v for Parcel Delivery Applications 1

Model Predictive Control of a Hybrid VA v for Parcel Deliver...

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1st AIRPHARO Workshop on Aerial Robotic systems Physically Interacting with the Environment, AIRPHARO 2021

作者： Konyalioglu, Turan Alnipak, Sinan Altug, Erdinc İstanbul Technical University System Dynamics and Control Graduate Program İstanbul Technical University Autonomous Systems Research Laboratory Department of Mechanical Engineering İstanbul Turkey

ISBN: (纸本)9781665433891

Within the last decade, e-commerce has increased at an extraordinary level. The widespread use of Unmanned Aerial Vehicles (VAVs) in the logistics sector can reduce traffic density, improve delivery time, and can provide contactless delivery. This work proposes a new hybrid VAV, that combines the benefits of vertical take-off and land vehicle and a fixed-wing aircraft. It can carry multiple packages, which can decent automatically towards the recipients. This approach eliminates time-consuming landing maneuvers of the VA V for delivery. This work focuses on the design of the vehicle, and the challenges of the transitions from VTOL to aircraft modes and vice versa with a Model Predictive Controller. © 2021 IEEE.

关键词： Fixed wings

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A Study on Giant Magnetostrictive Actuator for Interior Sound Control system of the Ultra-Compact Mobility: Fundamental Consideration on Formation of the Giant Magnetostrictive Phases Depending on Heat Treatment Condition 27

A Study on Giant Magnetostrictive Actuator for Interior Soun...

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27th International Conference on Electrical Machines and systems, ICEMS 2024

作者： Kato, Taro Naganuma, Ryusei Bando, Koki Sawada, Kentaro Wenbao, Wu Kobayashi, Ikkei Kuroda, Jumpei Uchino, Daigo Ogawa, Kazuki Ikeda, Keigo Endo, Ayato Kato, Hideaki Narita, Takayoshi Furui, Mitusaki Tokyo University of Technology Department of Mechanical Engineering 1404-1 Katakura Hachioji-shi Tokyo192-0982 Japan Sustainable Engineering Program Graduate School of Engineering Tokyo University of Technology 1404-1 Katakura Hachioji-shi Tokyo192-0982 Japan Tokai University Kitakaname 4-1-1 Kanagawa Hiratsuka-shi259-1292 Japan Tokai University Kitakaname 4-1-1 Kanagawa Hiratsuka-shi259-1292 Japan Numazu College Department of Mechanical Engineering Ohoka 3600 Shizuoka Numazu-shi410-0022 Japan Aichi University of Technology Department of Electronic Robotics 50-2 Manori Nishisako-machi Aichi Gamagori-shi443-0047 Japan Hokkaido University of Science Department of Mechanical Engineering 7-Jo 15-4-1 Maeda Teine Hokkaido Sapporo006-8585 Japan Fukuoka Institute of Technology Department of Electrical Engineering Wajiro Higashi 3-30-1 Higashi-ku Fukuoka Fukuoka-shi811-0295 Japan Tokai University Department of Mechanical System Engineering Kitakaname 4-1-1 Kanagawa Hiratsuka-shi259-1292 Japan

ISBN: (纸本)9784886864406

An active noise control system using giant magnetostrictive actuator has been proposed as a countermeasure for interior noise of the ultra-compact mobilities, which is a new transportation tools. In this paper, as basic research toward the development of the proposed giant magnetostrictive actuator for active noise control, we conduct experiments on the material properties when terbium, dysprosium, and iron powder, which make up the giant magnetostrictive material, are mixed and the heat treatment conditions are changed. In this study, the heat treatment temperature was varied from 800°C to 1100°C in 100°C incrementsbased on the equilibrium state temperature of each material, and the heat treatment time was set in 30-minute increments from 1 hour to 3 hours. As a result, TbFe2 was confirmed after heat treatment at an electric furnace temperature of 1000°C for 3 hours, although its strength was insufficient. © 2024 The Institute of Electrical Engineers of Japan.

关键词： Active noise control

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Design and free play analysis for a control mechanism of an insect-type fwmav

Design and free play analysis for a control mechanism of an ...

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AIAA Science and Technology Forum and Exposition, AIAA SciTech Forum 2021

作者： Choi, Jaewon Gong, Duhyun Yoon, Namkyung Shin, Sangjoon Interdisciplinary Program in Space System Seoul National University Seoul08826 Korea Republic of School of Mechanical and Aerospace Engineering Seoul National University Seoul08826 Korea Republic of

ISBN: (纸本)9781624106095

Unlike birds, insect type flapping wing mechanism does not have tail wings. Therefore, its fuselage attitude is adjusted by either varying direction of the stroke plane or twisting the trailing edge. In this paper, design and simulation of a control mechanism are to be presented. The control mechanism produces 3-axis moments by trailing edge control (TEC). TEC generates control moments by twisting a rod connected to the root of the main wings. For proper operation of TEC, kinematic analysis is conducted to determine its appropriate linkage length and the location of the mounted components. In addition, free play phenomenon caused by the backlash, which causes degradation in control ability, is also considered. Also, the wing shaft displacement caused by the free play is considerably decreased. To observe the control moments caused by the TEC, simulation is conducted by DYMORE software. The physical and aerodynamic phenomena caused by TEC are observed. Therefore, the prototype of the current mechanism is fabricated based on the analysis results. In the future, experiments for the proposed control mechanism will be conducted. Then, the control moment generated by the prototype will be evaluated and physical phenomena caused by the control moment will be observed. Also, a PID controller will be designed for stable flight based on numerical simulation results. © 2021, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.

关键词： Wings

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Autonomous aerial perching and unperching using omnidirectional tiltrotor and switching controller

Autonomous aerial perching and unperching using omnidirectio...

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IEEE International Conference on Robotics and Automation (ICRA)

作者： Dongjae Lee Sunwoo Hwang Jeonghyun Byun Seung Jae Lee H. Jin Kim Department of Aerospace Engineering Seoul National University (SNU) Seoul South Korea Department of Mechanical System Design Engineering Seoul National University of Science and Technology (SEOULTECH) Seoul South Korea Department of Aerospace Engineering and Interdisciplinary Program in Artificial Intelligence (IPAI) Seoul National University Seoul Korea

ISBN: (数字)9798350384574

ISBN: (纸本)9798350384581

Aerial unperching of multirotors has received little attention as opposed to perching that has been investigated to elongate operation time. This study presents a new aerial robot capable of both perching and unperching autonomously on/from a ferromagnetic surface during flight, and a switching controller to avoid rotor saturation and mitigate overshoot during transition between free-flight and perching. To enable stable perching and unperching maneuvers on/from a vertical surface, a lightweight (≈ 1 kg), fully actuated tiltrotor that can hover at 90 ◦ pitch angle is first developed. We design a perching/unperching module composed of a single servomotor and a magnet, which is then mounted on the tiltrotor. A switching controller including exclusive control modes for transitions between free-flight and perching is proposed. Lastly, we propose a simple yet effective strategy to ensure robust perching in the presence of measurement and control errors and avoid collisions with the perching site immediately after unperching. We validate the proposed framework in experiments where the tiltrotor successfully performs perching and unperching on/from a vertical surface during flight. We further show effectiveness of the proposed transition mode in the switching controller by ablation studies where large overshoot and even collision with a perching site occur. To the best of the authors’ knowledge, this work presents the first autonomous aerial unperching framework using a fully actuated tiltrotor.

关键词： Measurement uncertainty Rotors Switches Control systems Autonomous aerial vehicles Task analysis Servomotors

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Synthetic Data-Empowered Supervised Machine Learning Modeling for a Binary Fracture Risk Assessment from 2D-DXA Analysis

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SSRN 2023年

作者： Choi, Heesun Quagliato, Luca Chung, Yoon-Sok Lee, Taeyong Division of Mechanical and Biomedical Engineering Ewha Womans University Seoul03760 Korea Republic of Division of Mechanical and Biomedical Engineering Graduate Program in System Health Science and Engineering Ewha Womans University Seoul03760 Korea Republic of Department of Endocrinology and Metabolism Ajou University School of Medicine Suwon16499 Korea Republic of

Background and Objectives: Bone fracture risk assessment for osteopenia and osteoporotic patients is essential for the adoption of early countermeasures and avoiding discomfort and hospitalization. Currently employed methodologies, such as FRAX®, provides a risk assessment over a five to ten years period without showing the main variables influencing the prediction nor how they can be targeted in the short term. Thus, a lesser black-box approach where the fracture risk can be assessed in real-time from a commonly employed analysis, id est the dual-energy X-ray absorptiometry (2D-DXA), would be of help to clinicians and patients alike. Accordingly, this study presents three real-time machine learning (ML) assessment models, with distinct complexity, architectures, and performances, capable of predicting a binary fracture risk based on a femur head-hip joint 2D-DXA scan. Methods: A ~10,000 adult Korean gathered between 2017 and 2021 and composed of ~90% female and ~10% male ranging from 50 to 99 years of age was considered. 10% of the data is relevant to subjects who experienced skeletal fractures, among which 245 cases are femur fractures. The 2D-DXA analyses of the femur head-hip joint region carried out on patients allowed collecting 23 parameters, including the patient’s age, BMI, and gender, associated with one binary variable, defined in terms of non-fracture (NFX) or fracture (FX), to be employed as the training dataset for the three ML models employed and optimized in this research. The 2D-DXA results’ database (DB) was employed to train three ML classifiers with a binary (NFX/FX) output layer, namely the Extreme Gradient Boosting (XGB), the K-Nearest Neighbor (KNN), and Deep Neural Network (DNN). To avoid overfitting due to the higher number of NFX data with respect to FX one, two features augmentation techniques based on the Synthetic Minority Over-sampling Technique (SMOTE) and Oversample using Adaptive Synthetic (ADASYN) oversamplers were employed. For all

关键词： Fracture

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