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Vicki Chen - One of the best experts on this subject based on the ideXlab platform.
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fouling mitigation in submerged vmd for the treatment of brackish groundwater concentrates with Transverse Vibration and crystallizer
Desalination, 2018Co-Authors: Wenwei Zhong, Jingwei Hou, Vicki ChenAbstract:Abstract The management of brackish groundwater concentrates remains as a problem from the desalination of brackish groundwater. This study accessed the feasibility of various fouling mitigation techniques during the treatment of brackish groundwater concentrates at a 4-fold concentration factor for the purpose further volume reduction of wastewater. The study has demonstrated the importance of proper selection for fouling control techniques to the corresponding foulants. While vigorous agitations such as stirring could trigger earlier membrane deterioration in the brackish groundwater concentrates with inorganic foulants, a thermal crystallizer unit was able to effectively prolong membrane performance and promote the harvesting of calcium carbonates. On the other hand, vigorous Transverse Vibration of membrane module at 500 rpm showed significant improvement of the membrane performance in terms of anti-fouling, anti-wetting and water production for the treatment of brackish groundwater concentrates with the presence of humic substances. With the aid of Transverse Vibration, 8.7-fold concentration factor was achieved in brackish groundwater concentrates with humic substance at 70 °C.
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effect of operation parameters on the mass transfer and fouling in submerged vacuum membrane distillation crystallization vmdc for inland brine water treatment
Journal of Membrane Science, 2016Co-Authors: Helen Julian, Yun Ye, Suwan Meng, Hongyu Li, Vicki ChenAbstract:Membrane distillation-crystallization process has great potential to recover high quality water and valuable precipitates from inland brine water. Incorporation of submerging membrane in a feed tank with agitation provides opportunity to reduce temperature and concentration polarization and energy consumption. This study evaluated membrane Transverse Vibration and feed aeration on the mass transfer of water vapor, crystallization and fouling in a submerged vacuum membrane distillation and crystallization for inland brine water. At selected Vibration frequency, more than 700 h of high desalination performance was achieved. However, at elevated initial feed conductivity, the operation time was significantly reduced due to severe fouling.With accelerated tests with extreme feed concentration, both Transverse Vibration and aeration were able to increase the initial flux by reducing boundary layer thickness on the membrane surface. However, with Transverse Vibration, rapid reduction of flux occurred earlier due to the enhanced CaCO(3)precipitation on the membrane surface. The aeration of feed improved productivity with longer period of high flux with the increased nucleation in the bulk feed solution. Thermal water softening procedure prolonged the operation time by increased calcium precipitation in the feed solution and slower CaCO3 nucleation on the membrane surface.
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Transverse Vibration as novel membrane fouling mitigation strategy in anaerobic membrane bioreactor applications
Journal of Membrane Science, 2014Co-Authors: Anusha Kola, Pierre Leclech, Vicki ChenAbstract:While vibratory shear is effective for increasing the shear near the membrane surface, Transverse hollow fiber membrane Vibration offers additional mass transfer enhancement in terms of generating vortices in the wake of the vibrating surface. In this work, Transverse Vibration of submerged hollow fibers is explored for enhancing the filtration of anaerobic bioreactor effluents where gas sparging is often undesirable. The critical flux value was increased significantly with the aid of membrane Vibration. Even at high mixed liquid suspended solid concentrations, the vibratory system was still able to significantly reduce fouling. In addition to a reduced rate of fouling, fractionation of the fouling layer also showed that a more reversible fouling occurs with Vibrational filtration in comparison to traditional fouling limitation method such as gas sparging and crossflow. During the long term constant flux filtration with Vibration, a two-stage fouling phenomena was observed, similar with those observed in traditional MBR fouling but with a more extended initial low fouling stage. After the local permeate flux increased above the critical flux, the second rapid fouling stage occurred mainly due to cake formation. By appropriately coupling periodical backwash/relaxation with Vibrational filtration, the membrane performance was further improved. At low Vibration frequency, filtration with periodical relaxation displayed the best performance, whereas at high frequencies, coupling with periodic backwash was more beneficial.
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application of low frequency Transverse Vibration on fouling limitation in submerged hollow fibre membranes
Journal of Membrane Science, 2012Co-Authors: Anusha Kola, Pierre Leclech, Yun Ye, Amy Ho, Vicki ChenAbstract:Abstract Dynamic membrane systems provide highly turbulent flow regimes close to the membrane surface. In this work, flux enhancement of submerged hollow fibre membrane system was achieved by imposing rotationally oscillating fluid or Transverse oscillating membrane motion. The Transverse Vibration in the system generates the shear as well as secondary flows, contributing to fouling limitation even at low displacements (
Sondipon Adhikari - One of the best experts on this subject based on the ideXlab platform.
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in plane magnetic field affected Transverse Vibration of embedded single layer graphene sheets using equivalent nonlocal elasticity approach
Composite Structures, 2013Co-Authors: T Murmu, M A Mccarthy, Sondipon AdhikariAbstract:The behaviour of graphene in a magnetic field has attracted considerable attention among the scientific community. In this paper, the effect of an in-plane magnetic field on the Transverse Vibration of a magnetically sensitive single-layer graphene sheet (SLGS) is examined using equivalent continuum nonlocal elastic plate theory. The SLGS is considered to be embedded in an elastic medium. Governing equations for nonlocal Transverse Vibration of the SLGS under an in-plane magnetic field are derived considering the Lorentz magnetic force obtained from Maxwell’s relation. Numerical results from the model show that the in-plane magnetic field exerted on the SLGS increases the natural frequencies of the SLGS. This is in line with some reported results in the literature where macroscopic plates under an in-plane magnetic field are considered. Further, the nonlocal effects decrease the natural frequencies of the SLGS. The effects of the in-plane magnetic field on higher natural frequencies and different aspect ratios of SLGS are also presented.
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Vibration response of double walled carbon nanotubes subjected to an externally applied longitudinal magnetic field a nonlocal elasticity approach
Journal of Sound and Vibration, 2012Co-Authors: T Murmu, M A Mccarthy, Sondipon AdhikariAbstract:Abstract The magnetic properties of carbon nanotubes and their mechanical behaviour in a magnetic field have attracted considerable attention among the scientific and engineering communities. This paper reports an analytical approach to study the effect of a longitudinal magnetic field on the Transverse Vibration of a magnetically sensitive double-walled carbon nanotube (DWCNT). The study is based on nonlocal elasticity theory. Equivalent analytical nonlocal double-beam theory is utilised. Governing equations for nonlocal Transverse Vibration of the DWCNT under a longitudinal magnetic field are derived considering the Lorentz magnetic force obtained from Maxwell's relation. Numerical results from the model show that the longitudinal magnetic field increases the natural frequencies of the DWCNT. Both synchronous and asynchronous Vibration phases of the tubes are studied in detail. Synchronous Vibration phases of DWCNT are more affected by nonlocal effects than asynchronous Vibration phases. The effects of a longitudinal magnetic field on higher natural frequencies are also presented. Vibration response of DWCNT with outer-wall stationary and single-walled carbon nanotube under the effect of longitudinal magnetic field are also discussed in the paper.
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Transverse Vibration of single layer graphene sheets
Journal of Physics D, 2011Co-Authors: Rajib Chowdhury, Sondipon Adhikari, Fabrizio Scarpa, M I FriswellAbstract:We investigate the Vibrational properties of zigzag and armchair single-layer graphene sheets (SLGSs) using the molecular mechanics (MM) approach. The natural frequencies of Vibration and their associated intrinsic Vibration modes are obtained. Vibrational analysis is performed with different chirality and boundary conditions. The simulations are carried out for three types of zigzag and armchair SLGS. The universal force field potential is used for the MM approach. The first four natural frequencies are obtained for increasing lengths. The results indicate that the natural frequencies decrease as the length increases. The results follow similar trends with results of previous studies for SLGS using a continuum structural mechanics approach. These results have shown the applicability of SLGSs as electromechanical resonators. S Online supplementary data available from stacks.iop.org/JPhysD/44/205401/mmedia (Some figures in this article are in colour only in the electronic version)
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nonlocal Transverse Vibration of double nanobeam systems
Journal of Applied Physics, 2010Co-Authors: T Murmu, Sondipon AdhikariAbstract:Vibration analysis of double-nanobeam-systems is considered. Double-nanobeam-systems are important in nano-optomechanical systems and sensor applications. Expressions for free bending-Vibration of double-nanobeam-system are established within the framework of Eringen’s nonlocal elasticity theory. An analytical method is developed for determining the natural frequencies of the nonlocal double-nanobeam-system. Explicit closed-form expressions for natural frequencies are derived for the case when all four ends are simply-supported. The study highlights that the small-scale effects considerably influence the Transverse Vibration of double-nanobeam-systems. The nonlocal natural frequencies of double-nanobeam-system are smaller when compared to the corresponding local frequency values. The small-scale effects in the vibrating system are higher with increasing values of nonlocal parameter for the case of in-phase modes of Vibration than in the out-of-phase modes of Vibration. The increase in the stiffness of the coupling springs in double-nanobeam-system reduces the nonlocal effects during the out-of-phase modes of Vibration.
T Murmu - One of the best experts on this subject based on the ideXlab platform.
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in plane magnetic field affected Transverse Vibration of embedded single layer graphene sheets using equivalent nonlocal elasticity approach
Composite Structures, 2013Co-Authors: T Murmu, M A Mccarthy, Sondipon AdhikariAbstract:The behaviour of graphene in a magnetic field has attracted considerable attention among the scientific community. In this paper, the effect of an in-plane magnetic field on the Transverse Vibration of a magnetically sensitive single-layer graphene sheet (SLGS) is examined using equivalent continuum nonlocal elastic plate theory. The SLGS is considered to be embedded in an elastic medium. Governing equations for nonlocal Transverse Vibration of the SLGS under an in-plane magnetic field are derived considering the Lorentz magnetic force obtained from Maxwell’s relation. Numerical results from the model show that the in-plane magnetic field exerted on the SLGS increases the natural frequencies of the SLGS. This is in line with some reported results in the literature where macroscopic plates under an in-plane magnetic field are considered. Further, the nonlocal effects decrease the natural frequencies of the SLGS. The effects of the in-plane magnetic field on higher natural frequencies and different aspect ratios of SLGS are also presented.
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Vibration response of double walled carbon nanotubes subjected to an externally applied longitudinal magnetic field a nonlocal elasticity approach
Journal of Sound and Vibration, 2012Co-Authors: T Murmu, M A Mccarthy, Sondipon AdhikariAbstract:Abstract The magnetic properties of carbon nanotubes and their mechanical behaviour in a magnetic field have attracted considerable attention among the scientific and engineering communities. This paper reports an analytical approach to study the effect of a longitudinal magnetic field on the Transverse Vibration of a magnetically sensitive double-walled carbon nanotube (DWCNT). The study is based on nonlocal elasticity theory. Equivalent analytical nonlocal double-beam theory is utilised. Governing equations for nonlocal Transverse Vibration of the DWCNT under a longitudinal magnetic field are derived considering the Lorentz magnetic force obtained from Maxwell's relation. Numerical results from the model show that the longitudinal magnetic field increases the natural frequencies of the DWCNT. Both synchronous and asynchronous Vibration phases of the tubes are studied in detail. Synchronous Vibration phases of DWCNT are more affected by nonlocal effects than asynchronous Vibration phases. The effects of a longitudinal magnetic field on higher natural frequencies are also presented. Vibration response of DWCNT with outer-wall stationary and single-walled carbon nanotube under the effect of longitudinal magnetic field are also discussed in the paper.
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nonlocal Transverse Vibration of double nanobeam systems
Journal of Applied Physics, 2010Co-Authors: T Murmu, Sondipon AdhikariAbstract:Vibration analysis of double-nanobeam-systems is considered. Double-nanobeam-systems are important in nano-optomechanical systems and sensor applications. Expressions for free bending-Vibration of double-nanobeam-system are established within the framework of Eringen’s nonlocal elasticity theory. An analytical method is developed for determining the natural frequencies of the nonlocal double-nanobeam-system. Explicit closed-form expressions for natural frequencies are derived for the case when all four ends are simply-supported. The study highlights that the small-scale effects considerably influence the Transverse Vibration of double-nanobeam-systems. The nonlocal natural frequencies of double-nanobeam-system are smaller when compared to the corresponding local frequency values. The small-scale effects in the vibrating system are higher with increasing values of nonlocal parameter for the case of in-phase modes of Vibration than in the out-of-phase modes of Vibration. The increase in the stiffness of the coupling springs in double-nanobeam-system reduces the nonlocal effects during the out-of-phase modes of Vibration.
Liqun Chen - One of the best experts on this subject based on the ideXlab platform.
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DETC2005-84439 REDUCTION OF Vibration FOR AN AXIALLY MOVING STRING WITH A TENSIONER
2020Co-Authors: Liqun Chen, Wei ZhangAbstract:ABSTRACT This paper deals with reducing Transverse Vibration for an axially moving string by a damped tensioner. The governing equation and the boundary conditions are derived for the system. Based on the analysis of the reflection and transmission of waves propagating along the string, the maximal energy dissipation is realized by determining the optimal damping. To simulate numerically the effect of Vibration reduction, the Crank-Nicolson scheme is applied to discretize the governing equation of the string. The numerical results demonstrate the optimality of the determined damping in suppressing the Transverse Vibration
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nonlinear isolation of Transverse Vibration of pre pressure beams
Journal of Sound and Vibration, 2019Co-Authors: Hu Ding, Liqun ChenAbstract:Abstract Research on nonlinear isolation has always focused on the Vibration of discrete systems. The elastic Vibration of the main structure itself is always ignored. In order to study the influence of the multimodal elastic Vibration of the main structure on the nonlinear isolation effect, nonlinear isolation of the Transverse Vibration of a pre-pressure elastic beam is studied in this paper. Three linear springs are utilized to build a nonlinear isolation system, in which horizontal springs are utilized to provide non-linearity and to achieve quasi-zero stiffness. The Transverse Vibration of the beam is isolated by the elastic support at the two ends. The Galerkin truncation method (GTM) is used to solve the response of the forced Vibration. The isolation effect of the primary resonance of the pre-pressure beam is presented. The effects of the axial pre-pressure and nonlinear isolation system on Vibration transmission are explored. Results of the GTM are confirmed by utilizing the finite difference method (FDM). It also illustrates the effectiveness of the proposed difference method for nonlinear support structures. The numerical results demonstrate that under certain conditions, the quasi-zero stiffness isolation system may increase the transmission of high-order modal Vibration of the elastic continuum. Furthermore, this work finds that the initial axial pre-pressure could be beneficial to Vibration isolation of elastic structures.
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steady state Transverse response in coupled planar Vibration of axially moving viscoelastic beams
Journal of Vibration and Acoustics, 2010Co-Authors: Liqun Chen, Hu DingAbstract:Steady-state periodical response is investigated for planar Vibration of axially moving viscoelastic beams subjected external Transverse loads. A model of the coupled planar Vibration is established by introducing a coordinate transform. The model can reduce to two nonlinear models of Transverse Vibration. The finite difference scheme is developed to calculate steady-state response numerically. Numerical results demonstrate there are steady-state periodic responses in Transverse Vibration, and resonance occurs if the external load frequency approaches the linear natural frequencies. The effect of material parameters and excitation parameters on the amplitude of the steady-state responses are examined. Numerical results also indicate that the model of coupled Vibration and two models of Transverse Vibration predict qualitatively the same tendencies with the changing parameters, and the two models of Transverse Vibration yield satisfactory results.
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nonlinear free Transverse Vibration of an axially moving beam comparison of two models
Journal of Sound and Vibration, 2007Co-Authors: Liqun Chen, Xiaodong YangAbstract:Nonlinear free Transverse Vibration of an axially moving beam is investigated. A partial-differential equation governing the Transverse Vibration is derived from the Newton's second law. Under the assumption that the tension of beam can be replaced by the averaged tension over the beam, the partial-differential reduces to a widely used integro-partial-differential equation for nonlinear free Transverse Vibration. The method of multiple scales is applied directly to two equations to evaluate nonlinear natural frequencies. Numerical examples are presented to demonstrate the analytical results and to highlight the difference between two models. Two models yield the essentially same results for the weak nonlinearity, the small axial speed and the low mode, while the difference between two models increases with the nonlinear term, the axial speed, and the order of mode.
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A conserved quantity and the stability of axially moving nonlinear beams
Journal of Sound and Vibration, 2005Co-Authors: Liqun Chen, Wei-jia ZhaoAbstract:Free nonlinear Transverse Vibration is investigated for an axially moving beam modeled by an integro-partial-differential equation. Based on the equation, a conserved quantity is defined and confirmed for axially moving beams with pinned or clamped ends. The conserved quantity is applied to demonstrate the Lyapunov stability of the straight equilibrium configuration in Transverse nonlinear of beam with a low axial speed.
Anusha Kola - One of the best experts on this subject based on the ideXlab platform.
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Transverse Vibration as novel membrane fouling mitigation strategy in anaerobic membrane bioreactor applications
Journal of Membrane Science, 2014Co-Authors: Anusha Kola, Pierre Leclech, Vicki ChenAbstract:While vibratory shear is effective for increasing the shear near the membrane surface, Transverse hollow fiber membrane Vibration offers additional mass transfer enhancement in terms of generating vortices in the wake of the vibrating surface. In this work, Transverse Vibration of submerged hollow fibers is explored for enhancing the filtration of anaerobic bioreactor effluents where gas sparging is often undesirable. The critical flux value was increased significantly with the aid of membrane Vibration. Even at high mixed liquid suspended solid concentrations, the vibratory system was still able to significantly reduce fouling. In addition to a reduced rate of fouling, fractionation of the fouling layer also showed that a more reversible fouling occurs with Vibrational filtration in comparison to traditional fouling limitation method such as gas sparging and crossflow. During the long term constant flux filtration with Vibration, a two-stage fouling phenomena was observed, similar with those observed in traditional MBR fouling but with a more extended initial low fouling stage. After the local permeate flux increased above the critical flux, the second rapid fouling stage occurred mainly due to cake formation. By appropriately coupling periodical backwash/relaxation with Vibrational filtration, the membrane performance was further improved. At low Vibration frequency, filtration with periodical relaxation displayed the best performance, whereas at high frequencies, coupling with periodic backwash was more beneficial.
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application of low frequency Transverse Vibration on fouling limitation in submerged hollow fibre membranes
Journal of Membrane Science, 2012Co-Authors: Anusha Kola, Pierre Leclech, Yun Ye, Amy Ho, Vicki ChenAbstract:Abstract Dynamic membrane systems provide highly turbulent flow regimes close to the membrane surface. In this work, flux enhancement of submerged hollow fibre membrane system was achieved by imposing rotationally oscillating fluid or Transverse oscillating membrane motion. The Transverse Vibration in the system generates the shear as well as secondary flows, contributing to fouling limitation even at low displacements (
