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Assessment of Timoshenko Beam Models for vibrational Behavior of Single-Walled carbon Nanotubes using Molecular Dynamics

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Advances in Applied Mathematics and Mechanics 2009年第1期1卷 89-106页

作者： Y.Y.Zhang c.M.Wang v.B.c.Tan Department of Mechanical Engineering National University of SingaporeKent RidgeSingapore 119260 Engineering Science Programme and Department of civil Engineering National University of SingaporeKent RidgeSingapore 117574

In this paper,we study the flexural vibration behavior of single-walled carbon nanotubes(SWcNTs)for the assessment of Timoshenko beam ***tensive molecular dynamics(MD)simulations based on second-generation reactive empirical bond-order(REBO)potential and Timoshenko beam modeling are performed to determine the vibration frequencies for SWcNTs with various length-todiameter ratios,boundary conditions,chiral angles and initial *** effectiveness of the local and nonlocal Timoshenko beam models in the vibration analysis is assessed using the vibration frequencies of MD simulations as the *** is shown herein that the Timoshenko beam models with properly chosen parameters are applicable for the vibration analysis of *** simulation results show that the fundamental frequencies are independent of the chiral angles,but the chirality has an appreciable effect on higher vibration *** SWcNTs is very sensitive to the initial strain even if the strain is extremely small.

关键词： vibration carbon nanotubes molecular dynamics Timoshenko beam models

Artificial neural network with modified rider optimization for design and control of Pv-integrated quasi Z-source cascaded multilevel inverter system

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International Journal of Modeling, Simulation, and Scientific computing 2021年第1期12卷 87-111页

作者： v.c.Harish Kumar S.Amala Shanthi Department of EEE NICHE ThuckalayKanyakumariTamil NaduIndia Department of EcE NICHEThuckalayKanyakumariTamil NaduIndia

The modeling of the controller for quasi Z-Source cascaded Multilevel Inverter(qZScMI)-dependent 3-phase grid-tie Photovoltaic(Pv)power system is considered in this *** state-of-the-art controller requires precise conceptual models and sophisticated optimization principles based on the derived ***,such processes are limited to known system models,which are uncertain in future ***,the controller for 3-phase qZS-cMI is modeled based on two phases,and the source Pv voltage and output grid current are *** Phase I,optimized Proportional Integral(PI)controller is used for finding out the total Pv voltage,and Phase II utilizes the optimized Proportional Resonant(PR)controller enabled with the Artificial Neural Network(ANN)for controlling the grid *** two phases,the modified optimization algorithm called Fitness Enabled-Rider Optimization Algorithm(FE-ROA)is ***,in Phase II,ANN is trained in an offline mode with the exact dataset arranged by the proposed FE-ROA,and it guarantees the control of grid *** two phases plan to optimize the gain of both PI and PR controllers respectively using the same proposed *** main objective of phase I is to lessen the error among the reference Pv voltage,and measured voltage,and phase II is to lessen the error among the reference and measured grid ***,the grid-tie current injection is achieved by the developed module,and system-level control offers independent Maximum Power Point Tracking(MPPT).Lastly,the performance of the proposed controller for qZS-cMI is compared over the other controllers and substantiates the efficacy of the proposed one.

关键词： qZS-cMI PI controller PR controller artificial neural network fitness enabled-rider optimization algorithm

On conditionally Positive Definite Dot Product Kernels

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Acta Mathematica Sinica,English Series 2008年第7期24卷 1127-1138页

作者： v.A.MENEGATTO c.P.OLIvEIRA Ana P.PERON Departamento de Matemática ICMC-USP- Sāo CarlosCaixa Postal 66813560-970 Sāo Carlos SPBrasil Universidade Federal de Itajubá ICE-DMCCaixa Postal 5037500-903 ItajubáMGBrasil

Let m and n be fixed, positive integers and P a space composed of real polynomials in m variables. The authors study functions f ： R →R which map Gram matrices, based upon n points of R^m, into matrices, which are nonnegative definite with respect to P Among other things, the authors discuss continuity, differentiability, convexity, and convexity in the sense of Jensen, of such functions

关键词： conditionally positive definite kernels dot product kernels Gram matrices convexity convexity in the sense of Jensen

Spouting behavior of binary particle mixtures of different densities: Fluid dynamics and particle segregation

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Particuology 2019年第1期17卷 58-66页

作者： K.G. Santos R.c. Santana D.L. Souza v.v. Murata M.A.S. Barrozo Federal University ofTriangulo Mineiro Chemical Engineering DepartmentUniverdecidade CampusUberabaMGBrazil Federal University of Uberlandia Chemical Engineering SchoolUberlandiaMG. Brazil

Numerous industrial applications of spouted beds involve a mixture of granular particles, where differences in particle size, density, and shape can cause particle segregation, affecting the quality of flow and decreasing product homogeneity. The aim of this study was to investigate the particle segregation and fluid dynamics of a conical spouted bed operating with a binary mixture of particles of different densities. Using glass beads and polyethylene particles with a diameter of 4 mm, we determined the effects of the mass fraction of denser particles and static bed height on the minimum spouting condition and mixture index. The pressure drop and airflow in the minimum spouting condition increased with an increase in bed height or jetsam concentration. Regarding particle segregation, the jetsam particles tended to concentrate near the bottom, at the spout–annulus interface because they have a shorter trajectory than the lighter particles in the fountain region. Jetsam-rich mixtures with high initial static bed heights exhibited more efficient particle mixing, excluding those at the bottom of the bed.

关键词： Density Segregation Spouted bed Binary mixtures

control strategy for seamless transition from islanded to interconnected operation mode of microgrids

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Journal of Modern Power Systems and clean Energy 2017年第2期5卷 169-176页

作者： c.N.PAPADIMITRIOU v.A.KLEFTAKIS N.D.HATZIARGYRIOU Department of Electrical and computer Engineering National Technical University of Athens(NTUA)AthensGreece

Microgrids can operate either interconnected to the utility grid or disconnected forming an island. The transition between these modes can cause transient overcurrents or power oscillations jeopardizing the equipment safety or the system stability. This paper proposes a local multi agent control method for a seamless transfer between the islanded and interconnected modes of operation with agents implemented into the microgrid central switch(McS) and into the microsources inverters. The McS agent supervises the grid status and controls the switch for the transition of the microgrid through the different operation modes, while it communicates locally with the inverter agents of the microsources. The inverter agents undertake the synchronization process in case of reconnecting and change the inverter control mode depending on the grid status. Simulation and experimental results are presented to show the performance and feasibility of the proposed strategy.

关键词： Microgrid Islanding Reconnection Agents Synchronization control hardware-in-the-loop(cHIL)

Argo floats revealing bimodality of large-scale mid-depth circulation in the North Atlantic

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Acta Oceanologica Sinica 2008年第2期27卷 1-10页

作者： cHU Peter c IvANOv Leonid M MELNIcHENKO Oleg v LI Rongfeng Department of Oceanography Naval Postgraduate School Monterey California USA International Pacific Research center University of Hawaii at Manoa Hawaii USA Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China

Analysis of Argo float trajectories at 1 000 m and temperature at 950 m in the North Atlantic between November 2003 and January 2005 demonstrates the existence of two different circulation modes with fast transition between them. Each mode has a pair of cyclonic - anticyclonic gyres. The difference is the location of the cyclonic gyre. The cyclonic gyre stretches from southeast to northwest in the first mode and from the southwest to the northeast in the second mode. The observed modes strongly affect the heat and salt transport in the North Atlantic. In particular, the second mode slows down the westward transport of the warm and saline water from the Mediterranean Sea.

关键词： Argo trajectory data Atlantic Ocean biomodality mid-depth circulation optimal spectral decomposition

classification of Rings Associated with the Genus of clean Graphs

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Algebra colloquium 2024年第3期31卷 451-466页

作者： v.Ramanathan c.Selvaraj Aaqib Altaf S.Pirzada Department of Mathematics Periyar UniversitySalem 636011Tamil NaduIndi Department of Mathematics University of KashmirHazratbalSrinagarKashmirIndia

Let R be a ring(not necessarily commutative)with identity 1 and let cL(R)be its clean *** this paper,we investigate the genus number of the compact Riemann surface in which cL(R)can be embedded and explicitly determine all commutative rings R(up to isomorphism)such that cL(R)has genus at most *** is shown that for any Artinian ring R,cL(R)is a projective graph if and only if R is isomorphic to ***,we determine all isomorphism classes of commutative rings whose clean graphs have crosscap two.

关键词： clean graph commutative ring planar graph genus crosscap

Effect of fiber orientation in uni-directional glass epoxy laminate using acoustic emission monitoring

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Acta Metallurgica Sinica(English Letters) 2011年第5期24卷 351-364页

作者： v.Arumugam S.Barath Kumar c.Santulli A.Joseph Stanley Department of Aerospace Engineering Anna University Department of chemical Engineering Materials and EnvironmentUniversità La Sapienza MIT campus Anna University

Acoustic emission （AE） can be used for in situ structural health monitoring of the composite laminates. One of the main issues of AE is to characterize different damage mechanisms from the detected AE signals. In the present work, pure resin and GFRP composites laminates with different stacking sequences such as 0°, 90°, angle ply[±45°], cross-ply [0°/90°] are used to trigger different failure mechanisms when subjected to tensile test with AE monitoring. The study of failure mechanisms is facilitated by the choice of different oriented specimens in which one or two such mechanisms predominate. Range of peak frequencies in each orientation is investigated using FFT analysis. Fast Fourier Transform （FFT） enabled calculating the frequency content of each damage mechanism. Randomly selected hits from each range of peak frequencies for the specimens with different orientations subjected to tensile test with AE monitoring are analyzed using short time FFT （STFFT） analysis. STFFT analysis is used to highlight the possible failure mechanism associated with each signal. The predominance of failure modes in each orientation is useful in the study of discrimination of failure modes in composite laminates from AE data.

关键词： composite materials Failure mechanisms Acoustic emissionFFT analysis STFFT analysis

RE-ENGINEERING TRANSFORMER MAINTENANcE PROcESSES TO IMPROvE cUSTOMIZED SERvIcE DELIvERY

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Journal of Systems Science and Systems Engineering 2011年第3期20卷 323-345页

作者： Amy J.c. TRAPPEY Yong SUN charles v. TRAPPEY Lin MA Department of Industrial Engineering and Engineering Management National Tsing Hua University Taiwan China Department of Industrial Engineering and Management National Taipei University of Technology Taiwan China School of Engineering Systems Queensland University of Technology Australia Department of Management Science National Chiao Tung University Taiwan China

The outage of a transformer in a power generation system will generally result in a shutdown of the entire system. consequentially, large amounts of revenue are lost to the plant owner with a substantial negative impact on the civil community and industrial customers. This paper analyzes the current maintenance practices （i.e., an as-is process model） of a transformer manufacturing company, which provides maintenance services to power generation plants and reports the major weaknesses in current business practices. The maintenance weaknesses include isolated processes and paper based information communication. These inefficient processes result in service delays, cost increases, and inappropriate responses to customers＇ specific requests and complaints. To improve the efficiency and flexibility of the entire transformer maintenance service system, an e-integration approach is implemented with three key tasks. First, the current business processes are re-engineered to provide an improved （to-be） business model. Then, we replace paper based documentation methods with an electronic filing system for efficient and cost-effective information exchange. Afterward, the improved process model is implemented as an Internet based system to enhance the interactions among the transformer manufacturer, end-users, and service contractors for customized maintenance services. The case study demonstrates that implementing the e-integration approach increases the efficiency and effectiveness of the customized maintenance services.

关键词： Business Processes Reengineering (BPR) asset maintenance power industry after-sales services transformers engineering