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Finite element solution strategy for viscous dissipation in porous medium

AIP Conference Proceedings 2019年第1期2104卷

作者： Sarfaraz Kamangar Maughal Ahmed Ali Baig Azeem N. Ameer Ahamad Irfan Anjum Badruddin 1Department of Mechanical Engineering College of Engineering King Khalid University PO Box 394 Abha 61421. Kingdom of Saudi Arabia 2Department of Mechanical Engineering CMR Technical Campus Hyderabad India 3Department of Mathematics and Computer Science Taylor’s University No. 1 Jalan Taylor’s Subang Jaya - 47500 Selangor Darul Ehsan Malaysia 4Mathematics Department Faculty of Science University of Tabuk P.O.BOX.741 Zip.71491 Saudi Arabia 5Department of Mechanical Engineering College of Engineering King Khalid University PO Box 394 Abha 61421. Kingdom of Saudi Arabia

This article discusses the solution strategy to be adopted to solve the heat transfer in porous media having viscous dissipation effect. The solution strategy is based on finite element methodology being adopted to solve the equations. An iteratively procedure is used in order to predict the heat transfer behavior of porous medium confined in a square domain with heating and cooling of vertical walls.

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Machine discovery of partial differential equations from spatiotemporal data

arXiv

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arXiv 2019年

作者： Yuan, Ye Li, Junlin Li, Liang Jiang, Frank Tang, Xiuchuan Zhang, Fumin Liu, Sheng Goncalves, Jorge Voss, Henning U. Li, Xiuting Kurths, Jürgen Ding, Han School of Artificial Intelligence and Automation State Key Laboratory of Digital Manufacturing Equipments and Technology Huazhong University of Science and Technology Wuhan430074 China School of Artificial Intelligence and Automation Key Laboratory of Image Processing and Intelligent Control Huazhong University of Science and Technology Wuhan430074 China School of Electrical Engineering and Computer Science KTH Royal Institute of Technology Stockholm11428 Sweden School of Mechanical Science and Engineering Huazhong University of Science and Technology Wuhan430074 China School of Electrical and Computer Engineering Georgia Institute of Technology Atlanta30332 United States School of Power and Mechanical Engineering Wuhan University Wuhan430074 China Department of Engineering University of Cambridge CambridgeCB2 1PZ United Kingdom Luxembourg Centre for Systems Biomedicine University of Luxembourg BelvauxL-4367 Luxembourg Citigroup Biomedical Imaging Center Weill Cornell Medical College New York10021 United States Research Domain IV - Transdisciplinary Concepts & Methods Potsdam Institute for Climate Impact Research Potsdam14473 Germany School of Mechanical Science and Engineering State Key Laboratory of Digital Manufacturing Equipments and Technology Huazhong University of Science and Technology Wuhan430074 China

The study presents a general framework for discovering underlying Partial Differential Equations (PDEs) using measured spatiotemporal data. The method, called Sparse Spatiotemporal System Discovery (S3d), decides which physical terms are necessary and which can be removed (because they are physically negligible in the sense that they do not affect the dynamics too much) from a pool of candidate functions. The method is built on the recent development of Sparse Bayesian Learning;which enforces the sparsity in the to-be-identified PDEs, and therefore can balance the model complexity and fitting error with theoretical guarantees. Without leveraging prior knowledge or assumptions in the discovery process, we use an automated approach to discover ten types of PDEs, including the famous Navier-Stokes and sine-Gordon equations, from simulation data alone. Moreover, we demonstrate our data-driven discovery process with the Complex Ginzburg-Landau Equation (CGLE) using data measured from a traveling-wave convection experiment. Our machine discovery approach presents solutions that has the potential to inspire, support and assist physicists for the establishment of physical laws from measured spatiotemporal data, especially in notorious fields that are often too complex to allow a straightforward establishment of physical law, such as biophysics, fluid dynamics, neuroscience or nonlinear optics. Copyright © 2019, The Authors. All rights reserved.

关键词： Nonlinear optics

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Implementing statistical analysis in multi-channel acoustic impact-echo testing of concrete bridge decks: Determining thresholds for delamination detection

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AIP Conference Proceedings 2018年第1期1949卷

作者： Lorin Hendricks W. Spencer Guthrie Brian Mazzeo 1Department of Electrical and Computer Engineering Brigham Young University Provo Utah USA 2Department of Civil and Environmental Engineering Brigham Young University Provo Utah USA

An automated acoustic impact-echo testing device with seven channels has been developed for faster surveying of bridge decks. Due to potential variations in bridge deck overlay thickness, varying conditions between testing passes, and occasional imprecise equipment calibrations, a method that can account for variations in deck properties and testing conditions was necessary to correctly interpret the acoustic data. A new methodology involving statistical analyses was therefore developed. After acoustic impact-echo data are collected and analyzed, the results are normalized by the median for each channel, a Gaussian distribution is fit to the histogram of the data, and the Kullback-Leibler divergence test or Otsu’s method is then used to determine the optimum threshold for differentiating between intact and delaminated concrete. The new methodology was successfully applied to individual channels of previously unusable acoustic impact-echo data obtained from a three-lane interstate bridge deck surfaced with a polymer overlay, and the resulting delamination map compared very favorably with the results of a manual deck sounding survey.

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Numerical study of heat transfer and chemical kinetics of solar thermochemical reactor for hydrogen production

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AIP Conference Proceedings 2018年第1期1984卷

作者： Achmad Rofi Irsyad Byunggi Kim Doan Hong Duc Saiful Hasmady bin Abu Hassan Kazuyoshi Fushinobu 1Department of Mechanical and Control Engineering Tokyo Institute of Technology Japan 2University of Engineering and Technology VNU Hanoi Vietnam 3Department of Mechanical Engineering Universiti Tenaga Nasional Malaysia

A solar thermochemical reactor is a device utilizing concentrated solar energy to conduct hydrogen gas production by two-step water-splitting by dissociation of a reactive material, such as zinc oxide (ZnO). Reactor design, heat transfer, and reaction kinetics contribute a significant portion to the achievement of high solar-to-fuel conversion efficiency. In this work, an investigation of an indirect-cavity type reactor design performance has been conducted by numerical simulation method by coupling the computational model of fluid flow, energy equation, discrete ordinate radiation, and species transport. The reactor consisted of a windowed cavity reactor with an array of five tubes containing the flow of the reactive material. Dissociation of ZnO in a steady state condition of the reactor has been assessed under 1,500 sun heat flux from quartz window. A parametric study has been performed for a variation of the particle’s mass flow rate, solar flux peak in, and reactor configuration. The cavity of the reactor was insulated by a ceramic and reflective material to reduce the conduction and radiation losses. Inert gas of Ar was injected into the tube as product carrier. Energy balance analysis and reactor efficiency calculation have been performed to analyze the reactor performance. The results showed that the thermal re-radiation through the window and thermal conduction through the cavity wall dominated the heat losses around 84 % in total. The best operating condition in this study was at a mass flow rate 0.05 g/s, peak-heat-in 2,000 kW/m2, and tubes configuration of the staggered-front dominant. Some recommendations to improve the research include changing the chemical reactant with other metal-oxide which has a lower reactivity, increasing the tubes number to absorb the solar irradiation, combining the metal-oxide decomposition with other processes which require less heat, and applying the special material in window side which can filter the high wavelength from

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Algorithms for highway-speed acoustic impact-echo evaluation of concrete bridge decks

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AIP Conference Proceedings 2018年第1期1949卷

作者： Brian A. Mazzeo W. Spencer Guthrie 1Department of Electrical and Computer Engineering Brigham Young University Provo Utah USA 2Department of Civil and Environmental Engineering Brigham Young University Provo Utah USA

A new acoustic impact-echo testing device has been developed for detecting and mapping delaminations in concrete bridge decks at highway speeds. The apparatus produces nearly continuous acoustic excitation of concrete bridge decks through rolling mats of chains that are placed around six wheels mounted to a hinged trailer. The wheels approximately span the width of a traffic lane, and the ability to remotely lower and raise the apparatus using a winch system allows continuous data collection without stationary traffic control or exposure of personnel to traffic. Microphones near the wheels are used to record the acoustic response of the bridge deck during testing. In conjunction with the development of this new apparatus, advances in the algorithms required for data analysis were needed. This paper describes the general framework of the algorithms developed for converting differential global positioning system data and multi-channel audio data into maps that can be used in support of engineering decisions about bridge deck maintenance, rehabilitation, and replacement (MR&R). Acquisition of position and audio data is coordinated on a laptop computer through a custom graphical user interface. All of the streams of data are synchronized with the universal computer time so that audio data can be associated with interpolated position information through data post-processing. The audio segments are individually processed according to particular detection algorithms that can adapt to variations in microphone sensitivity or particular chain excitations. Features that are greater than a predetermined threshold, which is held constant throughout the analysis, are then subjected to further analysis and included in a map that shows the results of the testing. Maps of data collected on a bridge deck using the new acoustic impact-echo testing device at different speeds ranging from approximately 10 km/h to 55 km/h indicate that the collected data are reasonably repeatable. Use of

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Cost-benefit analysis game for efficient storage allocation in cloud-centric Internet of Things systems: A game theoretic perspective 15

Cost-benefit analysis game for efficient storage allocation ...

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15th IFIP/IEEE International Symposium on Integrated Network and Service Management, IM 2017

作者： Skourletopoulos, Georgios Mavromoustakis, Constandinos X. Mastorakis, George Sahalos, John N. Batalla, Jordi Mongay Dobre, Ciprian Department of Computer Science University of Nicosia Nicosia Cyprus Department of Informatics Engineering Technological Educational Institute of Crete Heraklion Crete Greece Department of Physics Aristotle University of Thessaloniki Thessaloniki Greece National Institute of Telecommunications and Warsaw University of Technology Szachowa Str. 1 and Nowowiejska Str. 15/19 Warsaw Poland Department of Computer Science and Engineering Faculty of Automatic Control and Computers University Politehnica of Bucharest Bucharest Romania

ISBN: (纸本)9783901882890

The advances in Internet of Everything (IoE) and the market-oriented cloud computing have provided opportunities to resolve the challenges caused by the Internet of Things (IoT) infrastructure virtualization, capacity planning, data storage or complexity. The volume and types of IoT data motivate the need for a data storage framework towards the integration of both structured and unstructured data. In this paper, we propose a novel game theoretic technique for efficient and dynamic storage allocation in cloud-centric IoT systems. The benefit maximization problem is formulated as a cost-benefit analysis game investigating the storage capacity currently used in the cloud. In view of each player's strategy to lease additional storage capacity, the game property is analyzed and we prove that the game always admits a pure strategy Nash equilibrium. Since the player's decision affects the level of benefit maximization, we elaborate on a cost-optimal storage allocation incentive mechanism, which scales effectively once non-linear or linear demand for storage capacity occurs, towards achieving optimal leasing conditions on cloud storage and computing capacity level. The experimental validation tests prove the effectiveness of the proposed game theoretic approach allocating the requests for more storage capacity in a cost-effective manner, which achieves to maximize the benefits. © 2017 IFIP.

关键词： Distributed cloud

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Equipment for calibrating three earth pressure cells simultaneously

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AIP Conference Proceedings 2018年第1期1967卷

作者： Jiequn Liu Jinlong Liu Lei Zhu 1Department of Computer Science and Technology Hefei University Hefei 230601 China 2Department of Civil Engineering Hefei University Hefei 230601 China

An equipment for calibrating three earth pressure cells simultaneously is proposed in this article, which including the first level drum, the second level drum, the third level drum, loading platform and weighting blocks. The earth pressure cell is placed in the circular placing groove of drum, and the signal transmission line of earth pressure cell is embedded in the wire slot of drum and extended to outside of drum. The second level drum is embedded in the upper of the first level drum, the third level drum is embedded in the upper of the second level drum, and the loading platform is embedded in the upper of the third level drum. Three earth pressure cells could be calibrated simultaneously by adding weighting blocks gradually on the loading platform.

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System Properties of Implicit Passive Electrical Networks Descriptions

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IFAC-PapersOnLine 2017年第1期50卷 9242-9247页

作者： Karcanias N. Livada M. Leventides J. Systems and Control Research Centre School of Mathematics Computer Sciences & Engineering City University London Northampton Square London EC1V 0HB United Kingdom University of Athens Department of Economics Section of Mathematics and Informatics Pezmazoglou 8 Athens Greece

Redesigning systems by changing elements, topology, organization, augmenting the system by the addition of subsystems, or removing parts, is a major challenge for systems and control theory. A special case is the redesign of passive electric networks which aims to change the natural dynamics of the network (natural frequencies) by the above operations leading to a modification of the network. This requires changing the system to achieve the desirable natural frequencies and involves the selection of alternative values for dynamic elements and non-dynamic elements within a fixed interconnection topology and/or alteration of the interconnection topology and possible evolution of the network (increase of elements, branches). The use of state-space or transfer function models does not provide a suitable framework for the study of this problem, since every time such changes are introduced, a new state space or transfer function model has to be recalculated. The use of impedance and admittance modeling, provides a suitable framework for the study of network properties under the process of re-engineering transformations. This paper deals with the fundamental system properties of the impedance-admittance network description which provide the appropriate framework for network re-engineering. We identify the natural topologies expressing the structured transformations linked to the impedance-graph, admittance graph-topology of the network and examine issues such as network regularity, number of finite frequencies and provide characterization of them in terms of the basic network matrices. The implicit network representation introduced provides a natural framework for expressing the different types of re-engineering transformations which can be used for the study of the natural frequencies assignment. © 2017

关键词： linear networks Linear systems structured systems system models system theory

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Vertical electrical impedance evaluation of asphalt overlays on concrete bridge decks

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AIP Conference Proceedings 2018年第1期1949卷

作者： Jared S. Baxter W. Spencer Guthrie Tenli Waters Jeffrey D. Barton Brian A. Mazzeo 1Department of Electrical and Computer Engineering Brigham Young University Provo Utah USA 2Department of Civil and Environmental Engineering Brigham Young University Provo Utah USA

Vertical electrical impedance scanning of concrete bridge decks is a non-destructive method for quantifying the degree of protection provided to steel reinforcement against the ingress of corrosive agents. Four concrete bridge decks with asphalt overlays in northern Utah were evaluated using scanning vertical electrical impedance measurements in this study. At the time of testing, the bridges ranged in age from 21 to 34 years, and asphalt overlays had been in place for 7 to 22 years, depending on the bridge. Electrical impedance measurements were collected using a previously constructed apparatus that consisted of six probes spanning a transverse distance of 12 ft. The impedance measurements were compared to surface cracking observations and cores obtained from the same four bridge decks. The results presented in this paper demonstrate the utility of scanning vertical electrical impedance measurements for detecting cracks in asphalt overlays and quantifying their severity. In addition, the results demonstrate the sensitivity of impedance measurements to the presence of an intact membrane beneath the asphalt overlay.

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Dielectric cross-shaped resonator based metasurface for vortex beam generation in Mid-IR and THz wavelengths

arXiv

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arXiv 2019年

作者： Dharmavarapu, Raghu Izumi, Ken-Ichi Katayama, Ikufumi Ng, Soon Hock Vongsvivut, Jitraporn Tobin, Mark J. Kuchmizhak, Aleksandr Nishijima, Yoshiaki Bhattacharya, Shanti Juodkazis, Saulius Department of Electrical Engineering Indian Institute of Technology Madras Chennai600036 India Centre for Micro-Photonics Faculty of Science Engineering and Technology Swinburne University of Technology HawthornVIC3122 Australia Melbourne Centre for Nanofabrication ANFF 151 Wellington Road ClaytonVIC3168 Australia Physics Department Yokohama National University 79-5 Tokiwadai Hodogaya-ku Yokohama240-8501 Japan Infrared Microspectroscopy Beamline Australian Synchrotron ClaytonVIC3168 Australia Institute of Automation and Control Processes Far Eastern Branch Russian Academy of Sciences Vladivostok690041 Russia Far Eastern Federal University Vladivostok690090 Russia Department of Electrical and Computer Engineering Graduate School of Engineering Yokohama National University 79-5 Tokiwadai Hodogaya-ku Yokohama240-8501 Japan Institute of Advanced Sciences Yokohama National University 79-5 Tokiwadai Hodogaya-ku Yokohama240-8501 Japan School of Materials and Chemical Technology Tokyo Institute of Technology 2-12-1 Ookayama Meguro-ku Tokyo152-8550 Japan

Metasurfaces are engineered thin surfaces comprising two dimensional (2D) arrays of sub-wavelength spaced and sub-wavelength sized resonators. Metasurfaces can locally manipulate the amplitude, phase and polarization of light with high spatial resolution. In this study, we report numerical and experimental results of a vortex-beam-generating metasurface fabricated specifically for infrared (IR) and terahertz (THz) wavelengths. The designed metasurface consisted of a 2D array of dielectric cross-shaped resonators with spatially varying length, thereby providing desired spatially varying phase shift to the incident light. The metasurface was found to be insensitive to polarization of incident light. The dimensions of the cross-resonators were calculated using rigorous finite difference time domain (FDTD) analysis. The spectral scalability via physical scaling of meta resonators was demonstrated using two vortex generating optical elements operating at 8.8 μm (IR) and 0.78 THz (Terahertz). The vortex beam generated in the mid-IR spectral range was imaged using FTIR imaging miscroscope equipped with a focal plane array (FPA) detector. This design could be used for efficient wavefront shaping as well as various optical imaging applications in mid-IR spectral range, where polarization insensitivity is desired. Copyright © 2019, The Authors. All rights reserved.

关键词： Resonators

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