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Assessment of debonding failures in the sandwich plate of stern ramp door of ferry Ro-Ro using k-nearest neighbor algorithm

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AIP Conference Proceedings 2023年第1期2674卷

作者： Safri Adam Tuswan Tuswan Abdi Ismail Achmad Zubaydi Bambang Piscesa Aditya Rio Prabowo Information Technology Study Program Politeknik Aisyiyah Pontianak 78114 Pontianak Indonesia Department of Naval Architecture Institut Teknologi Sepuluh Nopember 60111 Surabaya Indonesia Department of Naval Architecture Universitas Diponegoro Semarang Indonesia Ship Machinery Study Program Faculty of Vocational Studies Indonesia Defense University Belu Indonesia Department of Civil Engineering Institut Teknologi Sepuluh Nopember 60111 Surabaya Indonesia Department of Mechanical Engineering Universitas Sebelas Maret Indonesia Surakarta Indonesia

The difficulty in controlling the proper bonding during manufacturing sandwich for ship structure is a major problem. One of the damage types that often occurs is debonding caused by the lack of the adhesive layer bond between the two faceplate materials and the sandwich core at the centre. Furthermore, the identification of damage in ship structure becomes essential to ensure the structural integrity and security issues. Based on the issues above, damage identification on the sandwich plate of Ferry Ro-Ro with several debonding ratios using the k-NN algorithm was proposed. The cross-validation method was used to check the validity of the proposed algorithm model in practice. The proposed models were analyzed with various k-fold values, k-NN values, and number of iterations to investigate the influence of the those parameters on the accuracy of the model. From the result, it can be found that increasing k-fold value is the best strategy to increase the accuracy of the model. However, increase number of neighbors (k) caused a bias so that the accuracy decreased. The tests resulted in the highest accuracy of 97.60% obtained at k-fold 11 with k=3 and 90 iterations. It can be summarized that the large number of k-folds and small k-NN parameters do not require large iterations to obtain high prediction results.

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A versatile data-driven framework for model-independent control of continuum manipulators interacting with obstructed environments with unknown geometry and stiffness

arXiv

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arXiv 2020年

作者： Alambeigi, Farshid Wang, Zerui Liu, Yun-Hui Taylor, Russell H. Armand, Mehran Department of Mechanical Engineering University of Texas at Austin AustinTX78712 United States Cornerstone Robotics Limited Hong Kong Department of Mechanical and Automation Engineering Chinese University of Hong Kong Shatin Hong Kong Hong Kong Laboratory for Computational Sensing and Robotics Johns Hopkins University BaltimoreMD21218 United States Applied Physics Laboratory Johns Hopkins University LaurelMD20723 United States

This paper addresses the problem of controlling a continuum manipulator (CM) in free or obstructed environments with no prior knowledge about the deformation behavior of the CM and the stiffness and geometry of the interacting obstructed environment. We propose a versatile data-driven priorimodel-independent (PMI) control framework, in which various control paradigms (e.g. CM's position or shape control) can be defined based on the provided feedback. This optimal iterative algorithm learns the deformation behavior of the CM in interaction with an unknown environment, in real time, and then accomplishes the defined control objective. To evaluate the scalability of the proposed framework, we integrated two different CMs, designed for medical applications, with the da Vinci Research Kit (dVRK). The performance and learning capability of the framework was investigated in 11 sets of experiments including PMI position and shape control in free and unknown obstructed environments as well as during manipulation of an unknown deformable object. We also evaluated the performance of our algorithm in an ex-vivo experiment with a lamb heart. The theoretical and experimental results demonstrate the adaptivity, versatility, and accuracy of the proposed framework and, therefore, its suitability for a variety of applications involving continuum manipulators. Copyright © 2020, The Authors. All rights reserved.

关键词： Manipulators

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Manipulating Fano coupling in all-dielectric meta-molecules

Manipulating Fano coupling in all-dielectric meta-molecules

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Novel Optical Materials and Applications, NOMA 2019

作者： Lin, Linhan Peng, Xiaolei Zheng, Yuebing Department of Mechanical Engineering University of Texas at Austin AustinTX78712 United States Materials Science and Engineering Program and Texas Materials Institute University of Texas at Austin AustinTX78712 United States

ISBN: (纸本)9781943580644

关键词： Beam scattering Electron beam lithography Fano resonance Laser beams Mie resonances Optical switching devices

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Employment of hyper-cycloidal oscillatory motion for finding the coefficient of rolling friction. Part 2: Experimental investigation 10

Employment of hyper-cycloidal oscillatory motion for finding...

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10th Product Design, robotics, Advanced mechanical and Mechatronic Systems and Innovation Conference, PRASIC 2018

作者： Ciornei, F.C. Pentiuc, R.-D. Alaci, S. Romanu, I.C. Irimescu, L. Buium, F. Mechanics and Technologies Department Stefan Cel Mare University of Suceava Romania Electrotechnics Department Stefan Cel Mare University of Suceava Romania Mechanical Engineering Mechatronics and Robotics Department Gheorghe Asachi Technical University of Iasi Romania

The paper presents a method for finding the characteristics of rolling friction between two cylindrical external surfaces. By choosing the motion between two parallel cylinders it results that a point from one of the cylinders describes a hyper-cycloidal curve when rolling over the other cylinder. The study is focused on the friction in ball bearings. Parts of the ball bearings to be studied are directly involved in materializing the hyper-cycloidal contact. Thus, the immobile circles are materialized by the outer surface of the external ring and the mobile circles are materialized by the spherical surfaces of the balls. The motion of a laser stick attached to the pendulum is filmed. Analyzing the movie, the numerical time dependence of angular amplitude decrease is obtained. The concordance between the experimental and theoretical angular amplitude damping directs to the value of coefficient of rolling friction. © Published under licence by IOP Publishing Ltd.

关键词： Friction

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Tissue Tension Permits Β-Catenin Phosphorylation to Drive Mesoderm Specification in Human Embryonic Stem Cells

SSRN

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SSRN 2023年

作者： Ayad, Nadia M.E. Lakins, Johnathon N. Ghagre, Ajinkya Ehrlicher, Allen J. Weaver, Valerie M. Graduate Program in Bioengineering University of California San Francisco University of California Berkeley San FranciscoCA94143 United States Center for Bioengineering and Tissue Regeneration Department of Surgery University of California San Francisco San FranciscoCA94143 United States Department of Bioengineering McGill University MontrealQCH3A 0E9 Canada Department of Bioengineering Department of Anatomy and Cell Biology Department of Biomedical Engineering Department of Mechanical Engineering Centre for Structural Biology Rosalind and Morris Goodman Cancer Institute McGill University MontrealQCH3A 1A3 Canada Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research University of California San Francisco San FranciscoCA94143 United States UCSF Comprehensive Cancer Center Helen Diller Family Cancer Research Center University of California San Francisco San FranciscoCA94143 United States Department of Bioengineering and Therapeutic Sciences Department of Radiation Oncology University of California San Francisco San FranciscoCA94143 United States

The role of morphogenetic forces in cell fate specification is an area of intense interest. Our prior studies suggested that the development of high cell-cell tension in human embryonic stem cells (hESC) colonies permits the Src-mediated phosphorylation of junctional β-catenin that accelerates its release to potentiate Wnt-dependent signaling critical for initiating mesoderm specification. Using an ectopically expressed nonphosphorylatable mutant of β-catenin (Y654F), we now provide direct evidence that impeding tension-dependent Src-mediated β-catenin phosphorylation impedes the expression of Brachyury (T) and the epithelial-to-mesenchymal transition (EMT) necessary for mesoderm specification. Addition of exogenous Wnt3a or inhibiting GSK3β activity rescued mesoderm expression, emphasizing the importance of force dependent Wnt signaling in regulating mechanomorphogenesis. Our work provides a framework for understanding tension-dependent β-catenin/Wnt signaling in the self-organization of tissues during developmental processes including gastrulation. © 2023, The Authors. All rights reserved.

关键词： Tissue

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Advancements in nanomaterials for solar energy harvesting: Challenges, innovations, and future prospects

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Chemical engineering Journal 2025年 516卷

作者： Sikandar Aftab Burragoni Sravanthi Goud Zeeshan Ali Mohammed A. Assiri Jae Hong Kim Najaf Rubab Erdi Akman Department of Artificial Intelligence and Robotics Sejong University Seoul 05006 Republic of Korea School of Chemical Engineering Yeungnam University Gyeongsan 38541 Republic of Korea Department of Biotechnology School of Sciences SR University Warangal 506371 Telangana India Department of Computer Science Virtual University of Pakistan Faisalabad Campus Faisalabad 38000 Pakistan Chemistry Department Faculty of Science King Khalid University P.O. Box 9004 Abha 61413 Saudi Arabia Department of Materials Science and Engineering Gachon University Seongnam 13120 Republic of Korea Department of Physics Kamil Ozdag Faculty of Science Karamanoglu Mehmetbey University 70200 Karaman Turkiye Department of Mechanical Engineering Recep Tayyip Erdogan University 53100 Rize Turkiye

To date, the advancement of clean and sustainable energy sources has been a primary focus of research, addressing the global increase in energy consumption and related environmental issues. The swift progress of nanomaterials in solar energy conversion has generated significant interest owing to their exceptional structural and optoelectronic characteristics. This review paper examines the cutting-edge innovations and practical implementations of nanomaterials such as nanoparticles, quantum dots, nanorods, nanospheres, nanoflowers, nanocomposites, nanotubes, and one-dimensional (1D) and two-dimensional (2D) materials in the development of next-generation solar cells. We examine the incorporation of mentioned nanomaterials as absorber layers, doping agents, and modification agents in several solar cell designs. These materials are perfect for increasing the scalability and efficiency of solar energy conversion systems because of their special qualities, which include enhanced charge carrier dynamics and tunable bandgaps. We address critical issues like scalability, cost, and environmental concerns while discussing their contributions to improving light absorption, charge separation, and device stability. Moreover, this review clarifies the new device architectures utilizing nanomaterials as absorber layers, revealing the complex mechanisms that contribute to their enhanced performance and realistic stability behaviors. In order to overcome obstacles and fully utilize the potential of nanomaterials for sustainable energy solutions, we conclude by outlining future directions with a focus on interdisciplinary approaches. Interdisciplinary collaboration and ongoing refinement can fully realize the potential of new kinds of nanomaterials, offering significant solutions to global energy concerns and advancing scientific advancement in this emerging sector.

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Hopper flows of deformable particles

arXiv

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arXiv 2022年

作者： Cheng, Yuxuan Treado, John D. Lonial, Ben Habdas, Piotr Weeks, Eric R. Shattuck, Mark D. O'Hern, Corey S. Department of Physics Yale University New HavenCT06520 United States Department of Mechanical Engineering and Materials Science Yale University New HavenCT06520 United States Department of Physics Emory University AtlantaGA30322 United States Department of Physics Saint Joseph's University PhiladelphiaPA19131 United States Benjamin Levich Institute Physics Department The City College of New York New YorkNY10031 United States Program in Computational Biology and Bioinformatics Yale University New HavenCT06520 United States

Numerous experimental and computational studies show that continuous hopper flows of granular materials obey the Beverloo equation that relates the volume flow rate Q and the orifice width w: Q ∼ (w/σavg − k)β, where σavg is the average particle diameter, kσavg is an offset where Q ∼ 0, the power-law scaling exponent β = d − 1/2, and d is the spatial dimension. Recent studies of hopper flows of deformable particles in different background fluids suggest that the particle stiffness and dissipation mechanism can also strongly affect the power-law scaling exponent β. We carry out computational studies of hopper flows of deformable particles with both kinetic friction and background fluid dissipation in two and three dimensions. We show that the exponent β varies continuously with the ratio of the viscous drag to the kinetic friction coefficient, λ = ζ/µ. β = d−1/2 in the λ → 0 limit and d− 3/2 in the λ → ∞ limit, with a midpoint λc that depends on the hopper opening angle θw. We also characterize the spatial structure of the flows and associate changes in spatial structure of the hopper flows to changes in the exponent β. The offset k increases with particle stiffness until k ∼ kmax in the hard-particle limit, where kmax ∼ 3.5 is larger for λ → ∞ compared to that for λ → 0. Finally, we show that the simulations of hopper flows of deformable particles in the λ → ∞ limit recapitulate the experimental results for quasi-2D hopper flows of oil droplets in water. © 2022, CC BY.

关键词： Stiffness

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Experimental evidence of kinetically driven mechanisms for soot inception

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Communications chemistry 2025年第1期8卷 162页

作者： Hope A Michelsen Matthew F Campbell K Olof Johansson Paul E Schrader Kevin R Wilson Department of Mechanical Engineering Environmental Engineering Program University of Colorado Boulder Boulder CO USA. Hope.Michelsen@colorado.edu. Combustion Research Facility Sandia National Laboratories Livermore CA USA. Hope.Michelsen@colorado.edu. Combustion Research Facility Sandia National Laboratories Livermore CA USA. Department of Mechanical Engineering and Applied Mechanics University of Pennsylvania Philadelphia PA USA. KLA Corporation Milpitas CA USA. Chemical Sciences Division Lawrence Berkeley National Laboratory Berkeley CA USA. KRWilson@lbl.gov.

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The effect of passenger interaction on situation awareness and driving performance in sleep-deprived condition 5

The effect of passenger interaction on situation awareness a...

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5th International Conference on Science and Technology, ICST 2019

作者： Rizalmi, Sigit Rahmat Wijayanto, Titis Rossano, Ruliff Trapsilawati, Fitri Marcillia, Syam Rachma Lufityanto, Galang Universitas Gadjah Mada Industrial Engineering Postgraduate Program Yogyakarta Indonesia Universitas Gadjah Mada Mechanical and Industrial Engineering Department Yogyakarta Indonesia Universitas Gadjah Mada Industrial Engineering Undergraduate Program Yogyakarta Indonesia Universitas Gadjah Mada Architecture and Planning Department Yogyakarta Indonesia Universitas Gadjah Mada Faculty of Psychology Yogyakarta Indonesia

ISBN: (纸本)9781728123691

The present study investigates the effect of conversational interaction with a passenger on situation awareness and driving performance during driving in sleep-deprived condition. Twelve male students with mean (±SE) age of 22 (±2) years old participated in this study. They were requested to drive following a 20-min predetermined urban route after 24 h sleep deprivation in the morning on two separated driving sessions. Each drive included either without passenger or with passenger interaction. The results showed that passenger interaction during drowsy driving significantly improved drivers' situation awareness without enhancing driving performance. From these findings, it suggests that passenger interaction may be beneficial in improving situation awareness during driving in a sleep-deprived condition. © 2019 IEEE.

关键词： Automobile drivers

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Structured time-delay models for dynamical systems with connections to Frenet-Serret frame

arXiv

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arXiv 2021年

作者： Hirsh, Seth M. Ichinaga, Sara M. Brunton, Steven L. Kutz, J. Nathan Brunton, Bingni W. Department of Physics University of Washington SeattleWA United States Applied and Computational Mathematical Sciences Program University of Washington SeattleWA United States Department of Mechanical Engineering University of Washington SeattleWA United States Department of Applied Mathematics University of Washington SeattleWA United States Department of Biology University of Washington SeattleWA United States

Time-delay embeddings and dimensionality reduction are powerful techniques for discovering effective coordinate systems to represent the dynamics of physical systems. Recently, it has been shown that models identified by dynamic mode decomposition (DMD) on time-delay coordinates provide linear representations of strongly nonlinear systems, in the so-called Hankel alternative view of Koopman (HAVOK) approach. Curiously, the resulting linear model has a matrix representation that is approximately antisymmetric and tridiagonal with a zero diagonal;for chaotic systems, there is an additional forcing term in the last component. In this paper, we establish a new theoretical connection between HAVOK and the Frenet-Serret frame from differential geometry, and also develop an improved algorithm to identify more stable and accurate models from less data. In particular, we show that the sub- and super-diagonal entries of the linear model correspond to the intrinsic curvatures in Frenet-Serret frame. Based on this connection, we modify the algorithm to promote this antisymmetric structure, even in the noisy, low-data limit. We demonstrate this improved modeling procedure on data from several nonlinear synthetic and real-world examples. © 2021, CC BY.

关键词： Time delay

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