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arXiv 2021年

作者： Wang, Dong Treado, John D. Boromand, Arman Norwick, Blake Murrell, Michael P. Shattuck, Mark D. O'Hern, Corey S. Department of Mechanical Engineering and Materials Science Yale University New HavenCT06520 United States Integrated Graduate Program in Physical and Engineering Biology Yale University New HavenCT06520 United States Department of Physics Yale University New HavenCT06520 United States Department of Biomedical Engineering Yale University New HavenCT06520 United States Systems Biology Institute Yale University West HavenCT06516 United States Benjamin Levich Institute and Physics Department The City College of New York New YorkNY10031 United States Department of Applied Physics Yale University New HavenCT06520 United States

We investigate the structural, vibrational, and mechanical properties of jammed packings of deformable particles with shape degrees of freedom in three dimensions (3D). Each 3D deformable particle is modeled as a surface-triangulated polyhedron, with spherical vertices whose positions are determined by a shape-energy function with terms that constrain the particle surface area, volume, and curvature, and prevent interparticle overlap. We show that jammed packings of deformable particles without bending energy possess low-frequency, quartic vibrational modes, whose number decreases with increasing asphericity and matches the number of missing contacts relative to the isostatic value. In contrast, jammed packings of deformable particles with non-zero bending energy are isostatic in 3D, with no quartic modes. We find that the contributions to the eigenmodes of the dynamical matrix from the shape degrees of freedom are significant over the full range of frequency and shape parameters for particles with zero bending energy. We further show that the ensembleaveraged shear modulus hGi scales with pressure P as hGi ∼ pβ, with β ≈ 0.75 for jammed packings of deformable particles with zero bending energy. In contrast, β ≈ 0.5 for packings of deformable particles with non-zero bending energy, which matches the value for jammed packings of soft, spherical particles with fixed shape. These studies underscore the importance of incorporating particle deformability and shape change when modeling the properties of jammed soft materials. © 2021, CC BY.

关键词： Degrees of freedom (mechanics)

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Retraction notice to “Research on the kinetics characteristics and in-cylinder combustion of opposed rotary piston engine for different power output modes” [Appl. Therm. Eng. 249 (2024) 123362]

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Applied Thermal engineering 2024年 254卷

作者： Yufeng Wang Andy Thawko Ayat Gharehghani Jianbing Gao Xiaochen Wang Bingjian Wang Mingxu Qi Guohong Tian Haibo Chen School of Mechanical Engineering Beijing Institute of Technology Beijing 100081 China Grand Technion Energy Program Technion-Israel Institute of Technology Technion City Haifa 3200003 IL Israel School of Mechanical Engineering Iran University of Science and Technology Tehran 16846-13114 Iran Shaanxi Key Laboratory of New Transportation Energy and Automotive Energy Saving Chang’an University Xi’an 710064 China Beijing Product Quality Supervision and Inspection Institute National Automobile Inspection & Test Center (Beijing) Beijing 101399 China Department of Mechanical Engineering Sciences University of Surrey GU2 7XH UK Institute for Transport Studies University of Leeds Leeds LS2 9JT UK

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Direct Policy Optimization using Deterministic Sampling and Collocation

arXiv

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arXiv 2020年

作者： Howell, Taylor A. Fu, Chunjiang Manchester, Zachary The Department of Mechanical Engineering Stanford University StanfordCA94305 United States Frontier Robotics Innovative Research Excellence Honda R&D Co. Ltd. Wako-shi Saitama3510188 Japan The Robotics Institute Carnegie Mellon University PittsburghPA15213 United States

We present an approach for approximately solving discrete-time stochastic optimal-control problems by combining direct trajectory optimization, deterministic sampling, and policy optimization. Our feedback motion-planning algorithm uses a quasi-Newton method to simultaneously optimize a reference trajectory, a set of deterministically chosen sample trajectories, and a parameterized policy. We demonstrate that this approach exactly recovers LQR policies in the case of linear dynamics, quadratic objective, and Gaussian disturbances. We also demonstrate the algorithm on several nonlinear, underactuated robotic systems to highlight its performance and ability to handle control limits, safely avoid obstacles, and generate robust plans in the presence of unmodeled dynamics. Copyright © 2020, The Authors. All rights reserved.

关键词： Stochastic systems

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Design and Fabrication of a Biomimetic Circulatory Simulator with Overlaid Flow and Respiration Mechanism for Single Ventricle Physiology

Design and Fabrication of a Biomimetic Circulatory Simulator...

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IEEE/RAS-EMBS International Conference on Biomedical robotics and Biomechatronics (BioRob)

作者： M. A. Horvath D. Van Story J. Hochstein A. Pozo Alvarez M. Meboldt M. Schmid Daners E. T. Roche Institute for Medical Engineering and Science Massachusetts Institute of Technology Cambridge MA USA Health Science and Technology Program Harvard/Massachusetts Institute of Technology Cambridge MA USA Department of Mechanical and Process Engineering ETH Zurich Zurich Switzerland Harvard Medical School Boston MA USA Department of Industrial Engineering Universidad de Valladolid Spain

ISBN: (数字)9781728159072

ISBN: (纸本)9781728159089

Fontan surgery is performed for a wide range of patients with congenital cardiac defects. This palliative treatment connects the systemic and pulmonary vasculature in series which results in severe pathophysiological consequences. Mock circulatory flow loops for the Fontan circulation aim to better understand the complex physiology and provide a benchtop platform for device testing. In this work we describe the design and fabrication of a biomechatronic Fontan mock circulatory loop, guided by anatomy. We recreate Fontan flow by mimicking both respiratory and flow biomechanics. First, we build a respiratory simulator comprised of a thorax, abdomen, and a soft robotic diaphragm. Next, we design an electromechanical control system to activate the diaphragm and recreate pressure changes mimicking regular breathing. Then we overlay the respiratory simulator with a lumped parameterfluid model. The fluid model includes constant pressure head reservoirs as flow sources, a blood analog, compliance vessels, resistance valves, and a total cavompulmonary connection that is 3D printed from patient data. We achieve physiologic fluid dynamics, ranging from 0-2.3 l/min and pressures of 14-26 mmHg. A rigid windkessel compliance vessel was used to represent the upper body vasculature. Pulmonaty and abdominal vasculatures are subject to changing breathing pressures, to recreate this vasculature we designed elastic compliance vessels made of silicone membranes. Effective vessel compliance was characterized to be 50 ml/mmHg. Upon overlaying breathing mechanics with the flow system, which in Fontan patients accounts for up to 30 % of venous return, we see an impact of breathing pressures on flow in the inferior vena cava, which is representative of a Fontan patient.

关键词： Physiology Mathematical model Blood Abdomen Fluids Actuators Reservoirs

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The Design of a Parkinson’s Tremor Predictor and Estimator Using a Hybrid Convolutional-Multilayer Perceptron Neural Network

The Design of a Parkinson’s Tremor Predictor and Estimator ...

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Annual International Conference of the IEEE engineering in Medicine and Biology Society (EMBC)

作者： Anas Ibrahim Yue Zhou Mary E. Jenkins Ana Luisa Trejos Michael D. Naish Department of Electrical and Computer Engineering (ECE) Western University School of Biomedical Engineering (BME) Western University Movement Disorders Program Clinical logical Sciences Western University ECE and BME Western University Department of Mechanical and Materials neering ECE and BME Western University London ON Canada

ISBN: (数字)9781728119908

ISBN: (纸本)9781728119915

Parkinson's Disease (PD) is considered to be the second most common age-related neuroegenerative disorder, and it is estimated that seven to ten million people worldwide have PD. One of the symptoms of PD is tremor, and studies have shown that wearable assistive devices have the potential to assist in suppressing it. However, despite the progress in the development of these devices, their performance is limited by the tremor estimators they use. Thus, a need for a tremor model that helps the wearable assistive devices to increase tremor suppression without impeding voluntary motion remains. In this work, a user-independent and task-independent tremor and voluntary motion detection method based on neural networks is proposed. Inertial measurement units (IMUs) were used to measure acceleration and angular velocity from participants with PD, these data were then used to train the neural network. The achieved estimation percentage accuracy of voluntary motion was 99.0%, and the future prediction percentage accuracy was 97.3%, 93.7%, 91.4% and 90.3% for 10 ms, 20 ms, 50 ms and 100 ms ahead, respectively. The root mean squared error (RMSE) achieved for tremor estimation was an average of 0.00087 ° /s on new unseen data, and the future prediction average RMSE across the different tasks achieved was 0.001 ° /s, 0.002 ° /s, 0.020 ° /s and 0.049 ° /s for 1 ms, 2 ms, 5 ms, and 10 ms ahead, respectively. Therefore, the proposed method shows promise for use in wearable suppression devices.

关键词： Task analysis Neurons Convolution Feature extraction Estimation Neural networks Assistive devices

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Retraction notice to “Multi-attribute optimization of sustainable aviation fuel production-process from microalgae source” [Fuel 324(Part C) (2022) 124759]

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Fuel 2025年 391卷

作者： Zafar Said Tuan Hai Nguyen Prabhakar Sharma Changhe Li Hafiz Muhammad Ali Van Nhanh Nguyen Van Viet Pham Shams Forruque Ahmed Dong Nguyen Van Thanh Hai Truong Department of Sustainable and Renewable Energy Engineering University of Sharjah Sharjah P. O. Box 27272 United Arab Emirates U.S.-Pakistan Center for Advanced Studies in Energy (USPCAS-E) National University of Sciences and Technology (NUST) Islamabad Pakistan Faculty of Technology Dong Nai Technology University Dong Nai 76000 Viet Nam Mechanical Engineering Department Delhi Skill and Entrepreneurship University Delhi 110089 India School of Mechanical and Automotive Engineering Qingdao University of Technology Qingdao 266520 China Mechanical Engineering Department King Fahd University of Petroleum & Minerals Dhahran 31261 Saudi Arabia Interdisciplinary Research Center for Renewable Energy and Power Systems (IRC-REPS) King Fahd University of Petroleum and Minerals Dhahran 31261 Saudi Arabia Institute of Engineering HUTECH University Ho Chi Minh City Viet Nam Faculty of Marine Engineering Vietnam Maritime University Haiphong Viet Nam Science and Math Program Asian University for Women Chattogram 4000 Bangladesh University of Science and Technology The University of Danang Viet Nam PATET Research Group Ho Chi Minh City University of Transport Ho Chi Minh City Viet Nam

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Towards an intelligent wearable ankle robot for assistance to foot drop

Towards an intelligent wearable ankle robot for assistance t...

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IEEE International Conference on Systems, Man and Cybernetics

作者： Uriel Martinez-Hernandez Adrian Rubio-Solis Victor Cedeno-Campos Abbas A. Dehghani-Sanij Department of Electronic and Electrical Engineering and the Centre for Autonomous Robotics (CENTAUR) the University of Bath Bath UK Department of Automatic Control and Systems Engineering and the Department of Mechanical Engineering the University of Sheffield Sheffield UK School of Mechanical Engineering the University of Leeds Leeds UK

ISBN: (纸本)9781728145709

A wearable ankle robot prototype for assistance to foot drop is presented in this work. This device is built with soft and hard materials and employs one inertial sensor. First, the ankle robot uses a high-level method, developed with a Bayesian formulation, for recognition of walking activities and gait periods. Second, a low-level method, with a proportional-integral-derivative controller (PID), controls the wearable device to operate in assistive and transparent modes. In an assistive mode, activated by the toe-off detection, the wearable device assists the human foot in dorsiflexion orientation to reduce the effect of foot drop abnormality. In a transparent mode, activated by the heel-contact detection, the robot device follows the movements performed by the human foot. The wearable prototype is validated with experiments, in simulation and real-time modes, for recognition of walking activity and control of assistive and transparent modes during walking. Experiments achieved 99.87% and 99.20% accuracies for recognition of walking activity and gait periods. Results also show the ability of the wearable robot to operate according to the gait period recognised during walking. Overall, this work offers a wearable robot prototype with the potential to assist the human foot during walking, which is important to allow subjects to recover their confidence and quality of life.

关键词： Legged locomotion Foot Robot sensing systems Bayes methods Wearable robots Angular velocity

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Equipment Replacement Analysis from Manual Line to Automatic Line in Palletizing Activities: A Case Study

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IOP Conference Series: Materials Science and engineering 2021年第1期1096卷

作者： S D Susanti W Sutopo N H A Ngadiman Undergradute Program of Industrial Engineering Faculty of Engineering Sebelas Maret University Surakarta Indonesia Department of Industrial Engineering Faculty of Engineering Sebelas Maret University Surakarta Indonesia Universiti Teknologi Malaysia Faculty of Engineering School of Mechanical Engineering Department of Materials Manufacturing and Industrial Engineering Johor Bahru Malaysia

A decision situation often encountered by a company is whether an existing asset should be retired from use, continued in service, or replaced with new technology to improve productivity and competitiveness. The purpose of this paper is to present an equipment replacement analysis, an electronic components company. This study aims to analyze three proposed robots to automate the production line as a challenger versus an old manual production line as a defender in palletizing activities. We offered both Market and Technical analysis as well as investment analysis for evaluating an automatic line. Data are analyzed, and four methods are considered for determining project feasibility, namely NPV, IRR, Payback Period, and CBA. According to the data analysis, it is found that Borunte's robot is the best alternative compare with the others. The proposed framework of equipment analysis seems to be helpful to the company to solve equipment replacement studies.

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Antiviral drug-membrane permeability: The viral envelope and cellular organelles

arXiv

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arXiv 2020年

作者： Liu, Changjiang Elvati, Paolo Violi, Angela Biophysics Program University of Michigan Ann ArborMI48109-2125 United States Department of Mechanical Engineering University of Michigan Ann ArborMI48109-2125 United States Department of Chemical Engineering University of Michigan Ann ArborMI48109-2125 United States

To shorten the time required to find effective new drugs, like antivirals, a key parameter to consider is membrane permeability, as a compound intended for an intracellular target with poor permeability will have low efficacy. Here, we present a computational model that considers both drug characteristics and membrane properties for the rapid assessment of drugs permeability through the coronavirus envelope and various cellular membranes. We analyze 79 drugs that are considered as potential candidates for the treatment of SARS-CoV-2 and determine their time of permeation in different organelle membranes grouped by viral baits and mammalian processes. The computational results are correlated with experimental data, present in the literature, on bioavailability of the drugs, showing a negative correlation between fast permeation and most promising drugs. This model represents an important tool capable of evaluating how permeability affects the ability of compounds to reach both intended and unintended intracellular targets in an accurate and rapid way. The method is general and flexible and can be employed for a variety of molecules, from small drugs to nanoparticles, as well to a variety of biological membranes. Copyright © 2020, The Authors. All rights reserved.

关键词： Molecular dynamics

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Origami lattices and folding-induced lattice transformations

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Physical Review Research 2019年第2期1卷 023010-023010页

作者： Hongbin Fang Suyi Li Manoj Thota K. W. Wang Institute of AI and Robotics Fudan University Shanghai 200433 China Department of Mechanical Engineering University of Michigan Ann Arbor Michigan 48109 USA Department of Mechanical Engineering Clemson University Clemson South Carolina 29634 USA

Lattices and their underlying symmetries play a central role in determining the physical properties and applications of many natural and engineered materials. This research offers a comprehensive solution to a long-standing challenge regarding the lattice-based materials: how to systematically construct a lattice and transform it among different symmetric configurations in a predictable, scalable, and reversible way. By bridging the lattice geometry and rigid-folding kinematics of a group of origamis consisting of generic degree-4 vertices, we successfully construct all types of two- and three-dimensional Bravais lattices, and demonstrate that they can undergo all diffusionless phase transformations via rigid folding (i.e., dilation, extension, contraction, shear, and shuffle). Such folding-induced lattice transformations can trigger fundamental lattice-symmetry switches, which can either maintain or reconstruct the nearest-neighbor relationships according to a continuous symmetry measure. This study can foster the next generation of transformable lattice structures and materials with on-demand property tuning capabilities.

关键词： Microstructure Origami & Kirigami Phase transitions Metamaterials Symmetries Geometry Lattice models in condensed matter

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