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2nd International Congress on Ceramics, ICC 2008

作者： Acchar, W. Ramalho, E.G. Souza, F.B.M. Torquato, W.L. Department of Physics Federal University of Rio Grande Do Norte Natal-RN Brazil Pos-graduation Program of Mechanical Engineering Federal University of Rio Grande Do Norte Natal-RN Brazil Pos-graduation Program of Science and Materials Engineering Federal University of Rio Grande Do Norte Natal-RN Brazil

ISBN: (纸本)9788880800842

Ceramic porous structures are specially indicated for filters for molten metals, hot gases, thermal protection systems and heat exchangers, due their high permeability, good retention capacity, low density and high thermal insulation. This work describes the research carried out on mechanical properties of two different types of a commercial porous ceramic material (10 and 40 ppi). The ceramic material was characterized in terms of microstructural aspects, crystalline phases, density, porosity, strength and thermal shock behaviour. The results have indicated that the strength of the material remain practically constant, regardless of the temperature. The fracture analyses indicated that the fracture is normally caused by the presence of microcracks and also by the presence of a large amount of pores in the ceramic filaments.

关键词： Ceramic materials

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An End-to-End Proprioception Framework for Soft Continuum Robot

An End-to-End Proprioception Framework for Soft Continuum Ro...

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IEEE International Conference on robotics and Biomimetics

作者： Hanwen Cao Wei Chen Yiang Lu Junda Huang Jianshu Zhou Yunhui Liu Department of Mechanical and Automation Engineering The T Stone Robotics Institute The Chinese University of Hong Kong the Hong Kong Center for Logistics Robotics (HKCLR)

ISBN: (纸本)9781665481106

Soft robots are gaining more and more attention owing to their inherent compliance and excellent flexibility, enabling new potentials for robots to address real-world chal-lenges in the manner of their natural counterparts. The soft con-tinuum robot is one typical example that reflects the successful inspiration achievement from biomimetics to robotics. However, due to the nonlinearity and ultra-high degrees of freedom of soft continuum robots, traditional kinematic modeling methods obtain unsatisfying precision, especially when robots interact with their surroundings. To precisely estimate the kinematic model of soft continuum robots, we propose a novel end-to-end proprioception method. Our method inputs time series data from the soft continuum robot actuators and outputs the end-tip position in three dimensions. The experimental results show that the proposed method can improve the kinematic accuracy compared to the constant curvature model-based method either with contact or in noncontact conditions.

关键词： Actuators Biomimetics Biological system modeling Time series analysis Kinematics Soft robotics Robots

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Hierarchical on-line boosting based background subtraction

Hierarchical on-line boosting based background subtraction

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Korea-Japan Joint Workshop on Frontiers of Computer Vision

作者： Yongcheol Lee Jiyoung Jung In-So Kweon Robotics Program KAIST Daejeon South Korea Department of Electrical Engineering KAIST Daejeon South Korea

ISBN: (纸本)9781612846774

This paper presents a real-time background subtraction method which handles illumination changes and dynamic backgrounds such as flapping flags and waving trees. Previous approaches based on Gaussian mixture models usually generates models pixelwise, which makes it difficult to operate in realtime due to computational complexity. Moreover, pixelwise models tend to fail in sudden illumination changes or in dynamic backgrounds. In order to solve this problem, we propose an on-line boosting based background subtraction algorithm. Our approach divides the background area into overlapping patches instead of pixels, and learn classifiers with those patches. The main contribution of this paper is to propose a novel training process for classifiers which use block based Opponent Color Local Binary Pattern (OCLBP). Experimental results show that in environments containing illumination changes and/or dynamic backgrounds, our on-line boosting method using block based OCLBP outperforms previous on-line boosting methods or Gaussian mixture model based methods for robust background subtraction.

关键词： Boosting Training Pixel Image color analysis Lighting Computational modeling Heuristic algorithms

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Encrypted control for networked systems – An illustrative introduction and current challenges

arXiv

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arXiv 2020年

作者： Darup, Moritz Schulze Alexandru, Andreea B. Quevedo, Daniel E. Pappas, George J. Department of Mechanical Engineering TU Dortmund University Germany Department of Electrical and Systems Engineering University of Pennsylvania United States School of Electrical Engineering & Robotics Queensland University of Technology Australia

Cloud computing and distributed computing are becoming ubiquitous in many modern control systems such as smart grids, building automation, robot swarms or intelligent transportation systems. Compared to "isolated" control systems, the advantages of cloud-based and distributed control systems are, in particular, resource pooling and outsourcing, rapid scalability, and high performance. However, these capabilities do not come without risks. In fact, the involved communication and processing of sensitive data via public networks and on third-party platforms promote, among other cyberthreats, eavesdropping and manipulation of data. That these threats are relevant to real-world applications is apparent from an increasing number of cyberattacks explicitly addressing industrial control systems [90]. Prominent examples are the malwares Stuxnet, Duqu, Industroyer, or Triton (see, e.g., [16]) as well as inference attacks arising from smart meters used as surveillance devices (see, e.g. [60, 39]). Clearly, cyberattacks on control systems can be highly critical. In particular, unlike attacks on classical IT systems, attacks on control systems may influence physical processes through digital manipulations [88]. Moreover, networked control systems are the backbone of critical infrastructure such as electric power, transportation, and water distribution networks, with further applications illustrated in the sidebar "Prospective uses of encrypted control in industry". Hence, future control schemes should counteract privacy and security threats and ensure confidentiality, integrity, and availability (see [11] or [88, Fig. S1] for details on these traditional security goals) of the involved process data. Copyright © 2020, The Authors. All rights reserved.

关键词： Cybersecurity

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Experimental exergy analysis of the solar thermal system in the Off-Grid Zero Emissions Building

Experimental exergy analysis of the solar thermal system in ...

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Conference on Technologies for Sustainability (Sustech)

作者： Sam Yang Mauricio B. Chagas Tomas Solano Juan C. Ordonez Taylor Davis Jose V. C. Vargas Camilo Ordonez Department of Mechanical Engineering Center for Advanced Power Systems Florida State University Tallahassee FL USA Department of Mechanical Engineering Control and Robotics Florida State University Tallahassee FL USA

This paper presents an experimental exergy analysis of the solar thermal system in the Off-Grid Zero Emissions Building (OGZEB) at the Florida State University in efforts to identify components with major irreversibilities, i.e., exergy destruction. The solar thermal system comprises a series of flat-plate solar thermal collectors and 250-gal sensible thermal energy storage tank, and it is an essential constituent of the OGZEB heating system. In this study, exergy flow and destruction rates throughout the solar thermal system were evaluated using the experimental data obtained on two different days. According to the analysis, the greatest exergy destruction rate was observed in the solar thermal collector as expected, and its average exergetic efficiencies were 7.9% and 6.5% on each respective day. In the thermal energy storage tank, most of the exergy destruction was attributed to the mixing of hot water from the collector with the reservoir. This work serves as an initial step to the integrative thermodynamic optimization of the HVAC system in an off-grid residential building, where most energy is consumed for air-conditioning and heating.

关键词： Heat transfer Buildings Temperature measurement Sun Thermal analysis Thermal energy

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Improving STEM education for lower-division college students at HSI by utilizing relevant sociocultural and academic experiences: First year results from ASSURE-US project

Improving STEM education for lower-division college students...

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2020 ASEE Virtual Annual Conference, ASEE 2020

作者： Huang, Jidong Kurwadkar, Sudarshan Bein, Doina Bai, Yu Mayoral, Salvador Department of Electrical Engineering California State University Fullerton FullertonCA United States Department of Civil and Environmental Engineering California State University Fullerton FullertonCA United States Department of Computer Science California State University Fullerton FullertonCA United States Computer Engineering Program California State University Fullerton FullertonCA United States Department of Mechanical Engineering California State University Fullerton FullertonCA United States

Despite national efforts in increasing representation of minority students in STEM disciplines, disparities prevail. Hispanics account for 17.4% of the U.S. population, and nearly 20% of the youth population (21 years and below) in the U.S. is Hispanic, yet they account for just 7% of the STEM workforce. To tackle these challenges, the National Science Foundation (NSF) has granted a 5-year project - ASSURE-US, that seeks to improve undergraduate education in engineering and Computer Science (ECS) at California State University, Fullerton. The project seeks to advance student success during the first two years of college for ECS students. Towards that goal, the project incorporates a very diverse set of approaches, such as socio-cultural and academic interventions. Multiple strategies including developing early intervention strategies in gateway STEM courses, creating a nurturing faculty-student interaction and collaborative learning environment, providing relevant, contextual-based learning experiences, integrating project-based learning with engineering design in lower-division courses, exposing lower-division students to research to sustain student interests, and helping students develop career-readiness skills. The project also seeks to develop an understanding of the personal, social, cognitive, and contextual factors contributing to student persistence in STEM learning that can be used by STEM faculty to improve their pedagogical and student-interaction approaches. This paper summarizes the major approaches the ASSURE-US project plans to implement to reduce the achievement gap and motivate ECS students to remain in the program. Preliminary findings from the first-year implementation of the project including pre- and post- data were collected and analyzed from about one hundred freshmen and sophomore ECS students regarding their academic experience in lower-division classes and their feedback for various social support events held by the ASSURE-US project during

关键词： Students

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Pulse repetition interval-based excess fraction method for length measurement directly linked to a femtosecond optical frequency comb

Pulse repetition interval-based excess fraction method for l...

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Frontiers in Optics, FiO 2011

作者： Wei, Dong Takamasu, Kiyoshi Matsumoto, Hirokazu Global COE Program 'Mechanical Systems Innovation' School of Engineering The University of Tokyo 7-3-1 Hongo Bunkyo Tokyo 113-8656 Japan Department of Precision Engineering The University of Tokyo 7-3-1 Hongo Bunkyo Tokyo 113-8656 Japan

The principle of an arbitrary and absolute length measurement technique, called pulse repetition interval-based Excess Fraction method which is directly linked to a femtosecond optical frequency comb length standard t... 详细信息

ISBN: (纸本)9781557529176

关键词： Natural frequencies

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A Methodology for Longitudinal Tooth Flank Crowning of the Helical Gear on a CNC Honing Machine

A Methodology for Longitudinal Tooth Flank Crowning of the H...

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2014 2nd International Conference on Future Materials engineering and Industry Application(ICFMEIA 2014)

作者： Van-The Tran Ruei-Hung Hsu Chung-Biau Tsay Program of Mechanical and Aeronautical Engineering Feng Chia University Program in Precision System Design Feng Chia University Department of Mechanical and Computer-Aided Engineering Feng Chia University

The gear honing is the most economical way for hard finishing an involute helical gear after hobbing and heat treatment or after shaving and heat treatmentThe gear honing can also be applied to the modification of gear tooth surfaces to compensate for the distortions that occur during heat treatment processMost published papers on the technology of gear honing describes on the principle of generated gear surfaceHowever, the longitudinal tooth flank crowning of a helical gear with honing has not been investigated yetTherefore, in this paper, we proposed a novel method for longitudinal tooth flank crowning of work gear surfaces by setting a crossed angle between the honing cutter and work gear axes as a linear function of honing cutter's traverse feed in the honing processA mathematical model for the tooth profile of work gear honed by a standard honing cutter is also establishedThree numeral examples are presented to illustrate and verify the merits of the proposed gear honing method in longitudinal crowning.

关键词： Gear honing Longitudinal crowning Tooth flank Helical gear Mathematical model

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Actuation of a thumb prosthesis using remaining natural fingers

Actuation of a thumb prosthesis using remaining natural fing...

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IEEE International Workshop on Intelligent Robots and Systems (IROS)

作者： A. Vaz S. Hirai Department of Mechanical Engineering SLIET Longowal Sangrur Punjab India Department of Robotics Ritsumeikan University Kusatsu Shiga Japan

A simple but useful concept for the actuation of finger prosthesis, using the ability of remaining natural fingers of a partially deformed human hand, is presented in this work. The design is based on very simple principles drawn from the concept of opposition space. A prosthetic mechanism for a hand, which has lost a thumb but retains the abilities of the other fingers, is developed as an example to demonstrate the concept. This presentation is a system integration of the concept, design, modeling, simulation and development of the prosthetic mechanism. The system is modeled using the powerful technique of bond graphs. Effects such as extensibility of actuation strings and their internal damping, bearing friction at joints, etc., which are encountered in the prosthetic system, have been modeled and simulated. A simple prototype has been developed based on the proposed concept and demonstrated the effectiveness of the design. The prosthesis is very affordable and simple, and holds great promise for persons with such prehensile disabilities.

关键词： Thumb Prosthetics Fingers Humans Power system modeling Writing Tendons mechanical engineering Bonding Damping

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Simulation platform for self-assembly structures in MRI-guided nanorobotic drug delivery systems

Simulation platform for self-assembly structures in MRI-guid...

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IEEE International Conference on robotics and Automation (ICRA)

作者： Panagiotis Vartholomeos Constantinos Mavroidis Control Systems Lab Department of Mechanical Engineering National and Technical University of Athens Greece Bio Nano Robotics Laboratory Department of Mechanical and Industrial Engineering Northeastern University Boston MA USA

Magnetic Resonance Imaging (MRI) guided nanorobotic systems that could perform diagnostic, curative and reconstructive treatments in the human body at the cellular and sub-cellular level in a controllable manner have recently been proposed. The concept of a MRI-guided nanorobotic system is based on the use of a MRI scanner to induce the required external driving forces to guide magnetic nanocapsules to a specific target. However, the maximum magnetic gradient specifications of existing clinical MRI systems are not capable of driving superparamagnetic nanocapsules against the blood flow and therefore these MRIs do not allow for navigation. The present paper proposes a way to overcome this critical drawback through the formation of micron size agglomerations where their size can be regulated by external magnetic stimuli. This approach is investigated through modeling of the physics that govern the self-assembly of the nanoparticles. Additionally a computational tool has been developed that incorporates the derived models and performs simulation, visualization and post-processing analysis. Preliminary simulation results demonstrate that external magnetic field causes aggregation of nanoparticles while they flow in the vessel. This is a promising result -in accordance with similar experimental results- and encourages further investigation on the nanoparticle based self-assembly structures for use in nanorobotic drug delivery.

关键词： Self-assembly Nanostructures Drug delivery Magnetic resonance imaging Nanoparticles Computational modeling Biological system modeling Image reconstruction Humans Control systems

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