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Yonggang Leng - One of the best experts on this subject based on the ideXlab platform.

  • an Elastic Support model for enhanced bistable piezoelectric energy harvesting from random vibrations
    Journal of Applied Physics, 2015
    Co-Authors: Yonggang Leng, Yuji Gao, Dan Tan, Shengbo Fan, Zhihui Lai
    Abstract:

    To overcome the defect of conventional nonlinear piezoelectric cantilever vibration energy harvesters, in this paper we conceive an Elastic-Support model to study the performance of energy converters under two types of variable-intensity excitation conditions: filtered Gaussian noises and pink noises. When excitation intensity is insufficient, thanks to the system's variable potential function, frequent bistable transition oscillations between two wells occur in Elastic-Support systems, while only weak oscillations in either well could be observed in rigid-Support systems. In practical applications, the structural parameters of energy harvesters are not allowed to make real-time changes. If considered remaining the magnet interval and the spring's Elastic stiffness unchanged while receiving stable maximum output voltage, Elastic-Support systems can be made full use toward variable-intensity filtered Gaussian noises. It has been proven that Elastic-Support systems are capable of adapting to random excitations with variable intensity, through which maximum power output and sufficient electromechanical energy conversion of the system can be accomplished.

  • performance of bistable piezoelectric cantilever vibration energy harvesters with an Elastic Support external magnet
    Smart Materials and Structures, 2014
    Co-Authors: Yonggang Leng
    Abstract:

    Based on the research results of conventional rigid Support nonlinear energy harvesters, in this paper we conceive a kind of structure with an Elastic Support external magnet with the intent to keep the system in the state of bistable oscillation, even under low-intensity excitation conditions. It has been proved that Elastic Support systems have better power output performance than rigid Support systems when excited at low-intensity vibrations. In addition, Elastic Support nonlinear energy harvesters do not need real-time adjustment of the magnet interval towards the variable-intensity random excitation source, consequently achieving maximum power output and sufficient electromechanical energy conversion of the system.

Howard A Stone - One of the best experts on this subject based on the ideXlab platform.

  • the role of the membrane confinement for cell morphology and surface area regulation
    Biophysical Journal, 2012
    Co-Authors: Margarita Staykova, Marino Arroyo, Mohammad Rahimi, Howard A Stone
    Abstract:

    Commonly, the membranes of mammalian and plant cells are not isolated, but rather they are confined to an actin cortex on the inner side and to an extracellular matrix, cell wall or a substrate on the outer side. The confinement restricts the modes of the membrane deformation and so influences the mechanisms for shape remodeling and surface area regulation. To study the mechanics of confined membranes we developed an in vitro system, which couples a lipid bilayer to the strain-controlled deformation of an Elastic sheet (Staykova et al., PNAS 108:9084-9088, 2011). We demonstrate that upon contracting the Elastic Support, membrane protrusions grow out of the membrane plane, thus reducing its area; upon stretching, the bilayer absorbs the protrusions and expands its area without the lost of integrity. Most of our observations can be understood in terms of free energy minimization in a theoretical model we develop to account for stretch and curvature Elasticity of each monolayer, the adhesion with the substrate, and the limited amount of area and volume available to the protrusions. However, some of the observed morphologies are dynamical in nature, and simulations suggest that the friction between the lower monolayer and the substrate plays a key role. Our experimental and theoretical results closely reproduce membrane processes found in, for example, shrinking neurons, and plant and muscle cells, and thus offer a mechanistic approach towards understanding the area regulation in cells.

  • mechanics of surface area regulation in cells examined with confined lipid membranes
    Proceedings of the National Academy of Sciences of the United States of America, 2011
    Co-Authors: Margarita Staykova, Douglas P Holmes, Clarke Read, Howard A Stone
    Abstract:

    Cells are wrapped in inElastic membranes, yet they can sustain large mechanical strains by regulating their area. The area regulation in cells is achieved either by membrane folding or by membrane exo- and endocytosis. These processes involve complex morphological transformations of the cell membrane, i.e., invagination, vesicle fusion, and fission, whose precise mechanisms are still under debate. Here we provide mechanistic insights into the area regulation of cell membranes, based on the previously neglected role of membrane confinement, as well as on the strain-induced membrane tension. Commonly, the membranes of mammalian and plant cells are not isolated, but rather they are adhered to an extracellular matrix, the cytoskeleton, and to other cell membranes. Using a lipid bilayer, coupled to an Elastic sheet, we are able to demonstrate that, upon straining, the confined membrane is able to regulate passively its area. In particular, by stretching the Elastic Support, the bilayer laterally expands without rupture by fusing adhered lipid vesicles; upon compression, lipid tubes grow out of the membrane plane, thus reducing its area. These transformations are reversible, as we show using cycles of expansion and compression, and closely reproduce membrane processes found in cells during area regulation. Moreover, we demonstrate a new mechanism for the formation of lipid tubes in cells, which is driven by the membrane lateral compression and may therefore explain the various membrane tubules observed in shrinking cells.

Wael A Altabey - One of the best experts on this subject based on the ideXlab platform.

  • Applying deep learning and wavelet transform for predicting the vibration behavior in variable thickness skew composite plates with intermediate Elastic Support
    'JVE International Ltd.', 2021
    Co-Authors: Wael A Altabey
    Abstract:

    In this paper, the vibration behavior features are extracted from the combination between Wavelet Transform (WT), and Finite Strip Transition Matrix (FSTM) of skew composite plates (SCPs), with variable thickness, and intermediate Elastic Support. Although, the results of this technique and based on the previous work done by the authors, that show the method can reflect the vibration behavior of the composite plates. Due to the method's difficulty in terms of, a lot of calculations with a large number of iterations these results may not be good choices for quick and accurate vibration behavior extracting. Thus, the new deep neural network (NN) is designed to learn and test these results carrying out by extracting vibration behavior features that reflect the important and essential information about the mode shapes in SCP. The results give high indications about the proposed technique of deep learning is a promising method, particularly when the type structures are complicated and the ambient environment is variable

  • High performance estimations of natural frequency of basalt FRP laminated plates with intermediate Elastic Support using response surfaces method
    'JVE International Ltd.', 2018
    Co-Authors: Wael A Altabey
    Abstract:

    Studying the changes of the natural frequencies due to intermediate Elastic Support of laminated composites is usually need a lot of computational processes or difficult to estimate. The present study employs a new high performance method for natural frequency estimating in basalt fiber reinforced polymer (FRP) laminated, variable thickness plates with intermediate Elastic Support based on the finite strip transition matrix (FSTM) with response surfaces (RS) method. Author has found that the FSTM method is very effective. However, a large error of estimation remains for estimation of natural frequency due to the large number of an iteration implemented in FSTM algorithm to estimate the natural frequency. In the present study, a new data processing procedure is proposed to improve performance of estimations of natural frequency. The estimation responses for four of classical boundary conditions at the plate ends with different Elastic restraint coefficients (KT) are computed to obtain the first six frequency parameters (Ω). As a result, the method reveals excellent performance of estimations of natural frequencies

  • prediction of natural frequency of basalt fiber reinforced polymer frp laminated variable thickness plates with intermediate Elastic Support using artificial neural networks anns method
    Journal of Vibroengineering, 2017
    Co-Authors: Wael A Altabey
    Abstract:

    The paper is focused on the application of artificial neural networks (ANNs) in predicting the natural frequency of basalt fiber reinforced polymer (FRP) laminated, variable thickness plates. The author has found that the finite strip transition matrix (FSTM) approach is very effective to study the changes of plate natural frequencies due to intermediate Elastic Support (IES), but the method difficulty in terms of, a lot of calculations with large number of iterations is the main drawback of the method. For training and testing of the ANN model, a number of FSTM results for different classical boundary conditions (CBCs) with different values of Elastic restraint coefficients (KT) for IES have been carried out to training and testing an ANN model. The ANN model has been developed using multilayer perceptron (MLP) Feed-forward neural networks (FFNN). The adequacy of the developed model is verified by the regression coefficient (R2) and Mean Square error (MSE) It was found that the R2 and MSE values are 0.986 and 0.0134 for train and 0.9966 and 0.0122 for test data respectively. The results showed that, the training algorithm of FFNN was sufficient enough in predicting the natural frequency in basalt FRP laminated, variable thickness plates with IES. To judge the ability and efficiency of the developed ANN model, MSE has been used. The results predicted by ANN are in very good agreement with the FSTM results. Consequently, the ANN is show to be effective in predicting the natural frequency of laminated composite plates.

  • free vibration of basalt fiber reinforced polymer frp laminated variable thickness plates with intermediate Elastic Support using finite strip transition matrix fstm method
    Journal of Vibroengineering, 2017
    Co-Authors: Wael A Altabey
    Abstract:

    This paper presents a semi-analytical method to investigate the effect of intermediate Elastic Support on the natural frequencies of basalt fiber reinforced polymer (FRP) laminated, variable thickness plates based on the finite strip transition matrix (FSTM) method. The plate has a uniform thickness in x direction and varying thickness hy in y direction. A singular value decomposition algorithm is employed at the intermediate Support to eliminate the dependence of the solution of the first span on another span. By a new treatment of the intermediate line Support, the dimension of the final matrix of the general solution will be the same as that of plates without intermediate Support. Numerical results for different combinations of classical boundary conditions at the plate edges with different Elastic restraint coefficients (KT) for intermediate Elastic Support are presented to obtain the first six frequency parameters. The illustrated results are in excellent agreement with solutions available in the literature, thus validating the accuracy and reliability of the proposed technique.

Zhihui Lai - One of the best experts on this subject based on the ideXlab platform.

  • an Elastic Support model for enhanced bistable piezoelectric energy harvesting from random vibrations
    Journal of Applied Physics, 2015
    Co-Authors: Yonggang Leng, Yuji Gao, Dan Tan, Shengbo Fan, Zhihui Lai
    Abstract:

    To overcome the defect of conventional nonlinear piezoelectric cantilever vibration energy harvesters, in this paper we conceive an Elastic-Support model to study the performance of energy converters under two types of variable-intensity excitation conditions: filtered Gaussian noises and pink noises. When excitation intensity is insufficient, thanks to the system's variable potential function, frequent bistable transition oscillations between two wells occur in Elastic-Support systems, while only weak oscillations in either well could be observed in rigid-Support systems. In practical applications, the structural parameters of energy harvesters are not allowed to make real-time changes. If considered remaining the magnet interval and the spring's Elastic stiffness unchanged while receiving stable maximum output voltage, Elastic-Support systems can be made full use toward variable-intensity filtered Gaussian noises. It has been proven that Elastic-Support systems are capable of adapting to random excitations with variable intensity, through which maximum power output and sufficient electromechanical energy conversion of the system can be accomplished.

Mohammad Reza Zamani Kouhpanji - One of the best experts on this subject based on the ideXlab platform.