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A comprehensive study of treatment of arsenic in water combining oxidation,coagulation,and filtration

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Journal of Environmental Sciences 2015年第10期27卷 178-180页

作者： Terracciano Amalia Ge Jie Meng Xiaoguang Center for Environmental Engineering Stevens Institute of Technology

Arsenic is one of the most common inorganic contaminants in groundwater worldwide,mainly due to the release of naturally occurring arsenic from aquifer sediments（Amini et al.,2008;Li and Cai,2015;Rahman et al.,2015）... 详细信息

关键词： arsenic coagulation filtration predominantly ferric inorganic hydroxide groundwater remove adsorbed

Graph Theory Based N-1 Transmission Contingency Selection and Its Application in Security-constrained Unit Commitment

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Journal of Modern Power Systems and Clean Energy 2021年第6期9卷 1458-1467页

作者： Lu Nan Yikui Liu Lei Wu Tianqi Liu Chuan He College of Electrical Engineering Sichuan University the Department of Electrical and Computer Engineering Stevens Institute of Technology Department of Electrical and Computer Engineering Stevens Institute of Technology

Contingency analysis is an important building block in the stability and reliability analysis of power grid operations. However, due to the large number of transmission lines,in practice only a limited number of contingencies could be evaluated. This paper proposes a graph theory based N-1 contingency selection method to effectively identify the most critical contingencies, which can be used in security-constrained unit commitment(SCUC) problems to derive secure and economic operation decisions of the power grid. Specifically, the power flow transferring path identification algorithm and the vulnerability index are put forward to rank individual contingencies according to potential transmission line overloads. Effectiveness of the proposed N-1 contingency selection method is quantified by applying the corresponding SCUC solution to the full N-1 security evaluation, i. e., quantifying total post-contingency generation-load imbalance in all N-1 contingencies. Numerical results on several benchmark IEEE systems, including5-bus, 24-bus, and 118-bus systems, show effectiveness of the proposed method. Compared with existing contingency selection methods which usually resort to full power flow calculations,the proposed method relies on power gird topology to effectively identify critical contingencies for facilitating the optimal scheduling of SCUC problems.

关键词： Concentric relaxation contingency analysis graph theory security-constrained unit commitment(SCUC) shortest path vulnerability index

Privacy-Preserving Data Sharing in Cloud Computing

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Journal of Computer Science & technology 2010年第3期25卷 401-414页

作者：王慧 Department of Computer Science Stevens Institute of Technology Castle Point on Hudson

Storing and sharing databases in the cloud of computers raise serious concern of individual privacy. We consider two kinds of privacy risk： presence leakage, by which the attackers can explicitly identify individuals in （or not in） the database, and association leakage, by which the attackers can unambiguously associate individuals with sensitive information. However, the existing privacy-preserving data sharing techniques either fail to protect the presence privacy or incur considerable amounts of information loss. In this paper, we propose a novel technique, Ambiguity, to protect both presence privacy and association privacy with low information loss. We formally define the privacy model and quantify the privacy guarantee of Ambiguity against both presence leakage and association leakage. We prove both theoretically and empirically that the information loss of Ambiguity is always less than the classic generalization-based anonymization technique. We further propose an improved scheme, PriView, that can achieve better information loss than Ambiguity. We propose efficient algorithms to construct both Ambiguity and PriView schemes. Extensive experiments demonstrate the effectiveness and efficiency of both Ambiguity and PriView schemes.

关键词： privacy data sharing anonymity utility cloud computing

Revised barrier function-based adaptive finite-and fixed-time convergence super-twisting control

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Journal of Systems Engineering and Electronics 2023年第3期34卷 775-782页

作者： LIU Dakai ESCHE Sven Department of Mechanical Engineering Stevens Institute of TechnologyHoboken 07030USA

This paper presents an adaptive gain,finite-and fixedtime convergence super-twisting-like algorithm based on a revised barrier function,which is robust to perturbations with unknown *** is shown that this algorithm can ensure a finite-and fixed-time convergence of the sliding variable to the equilibrium,no matter what the initial conditions of the system states are,and maintain it there in a predefined vicinity of the origin without ***,the proposed method avoids the problem of overestimation of the control gain that exists in the current fixed-time adaptive ***,it shows that the revised barrier function can effectively reduce the computation load by obviating the need of increasing the magnitude of sampling step compared with the conventional barrier *** feature will be beneficial when the algorithm is implemented in *** that,the estimation of the fixed convergence time of the proposed method is derived and the impractical requirement of the preceding fixed-time adaptive control that the adaptive gains must be large enough to engender the sliding mode at time t=0 is ***,the outperformance of the proposed method over the existing counterpart method is demonstrated with a numerical simulation.

关键词： super-twisting algorithm barrier function fixed-time sliding mode control adaptive control

Spectrophotometric analyses of hexahydro-1,3,5-trinitro-1,3,5-triazine(RDX) in water

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Journal of Environmental Sciences 2015年第7期27卷 39-44页

作者： Cong Shi Zhonghou Xu Benjamin L.Smolinski Per M.Arienti Gregory O'Connor Xiaoguang Meng Center for Environmental Systems Stevens Institute of Technology US Army RDECOM-ARDEC

A simple and accurate spectrophotometric method for on-site analysis of royal demolition explosive（RDX） in water samples was developed based on the Berthelot reaction. The sensitivity and accuracy of an existing spectrophotometric method was improved by：replacing toxic chemicals with more stable and safer reagents; optimizing the reagent dose and reaction time; improving color stability; and eliminating the interference from inorganic nitrogen compounds in water samples. Cation and anion exchange resin cartridges were developed and used for sample pretreatment to eliminate the effect of ammonia and nitrate on RDX analyses. The detection limit of the method was determined to be 100 μg/L. The method was used successfully for analysis of RDX in untreated industrial wastewater samples. It can be used for on-site monitoring of RDX in wastewater for early detection of chemical spills and failure of wastewater treatment systems.

关键词： Berthelot reaction Exchange resins RDXS pectrophotometric method Water

Machine learning metrology of cell confinement in melt electrowritten threedimensional biomaterial substrates

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Microsystems & Nanoengineering 2019年第1期5卷 552-570页

作者： Filippos Tourlomousis Chao Jia Thrasyvoulos Karydis Andreas Mershin Hongjun Wang Dilhan M.Kalyon Robert C.Chang The Center for Bits and Atoms Massachusetts Institute of TechnologyCambridgeMAUSA Biomedical Engineering Department Stevens Institute of TechnologyHobokenNJUSA Chemical Engineering and Materials Science Department Stevens Institute of TechnologyHobokenNJUSA Mechanical Engineering Department Stevens Institute of TechnologyHobokenNJUSA

Tuning cell shape by altering the biophysical properties of biomaterial substrates on which cells operate would provide a potential shape-driven pathway to control cell ***,there is an unexplored dimensional scale window of three-dimensional(3D)substrates with precisely tunable porous microarchitectures and geometrical feature sizes at the cell’s operating length scales(10–100μm).This paper demonstrates the fabrication of such highfidelity fibrous substrates using a melt electrowriting(MEW)*** advanced manufacturing approach is biologically qualified with a metrology framework that models and classifies cell confinement states under various substrate dimensionalities and *** fibroblasts as a model cell system,the mechanosensing response of adherent cells is investigated as a function of variable substrate dimensionality(2D vs.3D)and porous microarchitecture(randomly oriented,“non-woven”***-stacked,“woven”).Single-cell confinement states are modeled using confocal fluorescence microscopy in conjunction with an automated single-cell bioimage data analysis workflow that extracts quantitative metrics of the whole cell and sub-cellular focal adhesion protein features *** extracted multidimensional dataset is employed to train a machine learning algorithm to classify cell shape *** results show that cells assume distinct confinement states that are enforced by the prescribed substrate dimensionalities and porous microarchitectures with the woven MEW substrates promoting the highest cell shape homogeneity compared to non-woven fibrous *** technology platform established here constitutes a significant step towards the development of integrated additive manufacturing—metrology platforms for a wide range of applications including fundamental mechanobiology studies and 3D bioprinting of tissue constructs to yield specific biological designs qualified at the single-cell level.

关键词： metrology prescribed printing

Hybrid Local-global Power-sharing Scheme for Droop-free Controlled Microgrids

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Journal of Modern Power Systems and Clean Energy 2024年第5期12卷 1520-1534页

作者： Kunyu Zuo Lei Wu Electrical and Computer Engineering Department Stevens Institute of TechnologyHobokenNJ 07030USA

The droop-free control adopted in microgrids has been designed to cope with global power-sharing goals,i.e.,sharing disturbance mitigation among all controllable assets to even their ***,limited by neighboring communication,the time-consuming peer-to-peer coordination of the droopfree control slows down the nodal convergence to global consensus,reducing the power-sharing efficiency as the number of nodes *** this end,this paper first proposes a local power-sharing droop-free control scheme to contain disturbances within nearby nodes,in order to reduce the number of nodes involved in the coordination and accelerate the convergence speed.A hybrid local-global power-sharing scheme is then put forward to leverage the merits of both schemes,which also enables the autonomous switching between local and global power-sharing modes according to the system *** guidance for key control parameter designs is derived via the optimal control methods,by optimizing the power-sharing distributions at the steady-state consensus as well as along the dynamic trajectory to *** system stability of the hybrid scheme is proved by the eigenvalue analysis and Lyapunov direct ***,simulation results validate that the proposed hybrid local-global power-sharing scheme performs stably against disturbances and achieves the expected control performance in local and global power-sharing modes as well as mode ***,compared with the classical global power-sharing scheme,the proposed scheme presents promising benefits in convergence speed and scalability.

关键词： Droop-free control power-sharing optimal control Lyapunov stability

Aperiodic tidal data resource assessment and LCOE analysis of selected areas in Nigeria

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Clean Energy 2018年第1期2卷 45-57页

作者： L.M.Amoo stevens Institute of technology HobokenNew Jersey 07030USA

Renewable energy is plentiful;we need only develop the technology to harness and distribute it efficiently and *** conversion of energy to electricity continues to be an area of interest for engineers and *** energy has been classified as one of five energy innovations that could transform our world-the others being fuel cells,lithium-air batteries,the smart grid,and space-based solar power(http://***/Alternative-Energy/Renewable-Energy/***).Resource engineering assessment constitutes the first step to the effective utilization of any *** are various candidate sites for tidal stream energy in *** objective of this research is to examine the tidal stream resource potential of seven coastal sites using the modified continuous wavelet transform(CWT)method with a levelized cost of energy(LCOE)***’s method is newly applied to the aperiodic tidal series *** results indicate that meaningful power is viable and could be economically extracted at each respective site,with peak mean approximate velocities at each site of~10 m/s,and the LCOE estimate was found to be lower than that of the International Renewable Energy Agency(IRENA).This work represents the culmination of a series of papers exploring tidal energy resources in tropical Nigeria.

关键词： tidal energy renewable energy continuous wavelet transform(CWT) LCOE Nigeria

A Closed-form Formulation of Eigenvalue Sensitivity Based on Matrix Calculus for Small-signal Stability Analysis in Power System

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Journal of Modern Power Systems and Clean Energy 2021年第6期9卷 1436-1445页

作者： Peijie Li Yucheng Wei Junjian Qi Xiaoqing Bai Hua Wei School of Electrical Engineering Guangxi University Department of Electrical and Computer Engineering Stevens Institute of Technology

With the rapid development of power-electronicsenabled power systems,the new converter-based generators are deteriorating the small-signal stability of the power *** the numerical differentiation method has been widely used for approximately calculating the eigenvalue sensitivities,its accuracy has not been carefully ***,the element-based formulation for computing closed-form eigenvalue sensitivities has not been used in any commercial software due to the average efficiency,complicated formulation,and errorprone *** on the matrix calculus,this paper proposes an easily manipulated formulation of the closed-form eigenvalue sensitivities with respect to the power *** distinguishing feature of the formulation is that all the formulas consist of vector and matrix operations,which can be performed by developed numerical algorithms to take full advantages of architectural features of the modern *** tests on WSCC 3-machine 9-bus system,New England 10-machine 39-bus system,and IEEE 54-machine 118-bus system show that the accuracy of the proposed formulation is superior to the numerical differentiation method and the efficiency is also greatly improved compared to the element-based closed-form *** proposed formulation will be helpful to perform a more accurate and faster stability analysis of a power grid with converter-based devices.

关键词： Closed-form formulation converter-based devices eigenvalue sensitivity matrix calculus small-signal stability