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Articles 1 - 22 of 22
Full-Text Articles in Science and Technology Studies
Osmotic Versus Conventional Membrane Bioreactors Integrated With Reverse Osmosis For Water Reuse: Biological Stability, Membrane Fouling, And Contaminant Removal, Wenhai Luo, Hop Phan, Ming Xie, Faisal I. Hai, William E. Price, Menachem Elimelech, Long D. Nghiem
Osmotic Versus Conventional Membrane Bioreactors Integrated With Reverse Osmosis For Water Reuse: Biological Stability, Membrane Fouling, And Contaminant Removal, Wenhai Luo, Hop Phan, Ming Xie, Faisal I. Hai, William E. Price, Menachem Elimelech, Long D. Nghiem
Faculty of Engineering and Information Sciences - Papers: Part A
This study systematically compares the performance of osmotic membrane bioreactor - reverse osmosis (OMBR-RO) and conventional membrane bioreactor - reverse osmosis (MBR-RO) for advanced wastewater treatment and water reuse. Both systems achieved effective removal of bulk organic matter and nutrients, and almost complete removal of all 31 trace organic contaminants investigated. They both could produce high quality water suitable for recycling applications. During OMBR-RO operation, salinity build-up in the bioreactor reduced the water flux and negatively impacted the system biological treatment by altering biomass characteristics and microbial community structure. In addition, the elevated salinity also increased soluble microbial products and …
Stability Control Of Force-Reflected Nonlinear Multilateral Teleoperation System Under Time-Varying Delays, Da Sun, Fazel Naghdy, Haiping Du
Stability Control Of Force-Reflected Nonlinear Multilateral Teleoperation System Under Time-Varying Delays, Da Sun, Fazel Naghdy, Haiping Du
Faculty of Engineering and Information Sciences - Papers: Part A
A novel control algorithm based on the modified wave-variable controllers is proposed to achieve accurate position synchronization and reasonable force tracking of the nonlinear single-master-multiple-slave teleoperation system and simultaneously guarantee overall system's stability in the presence of large time-varying delays. The system stability in different scenarios of human and environment situations has been analyzed. The proposed method is validated through experimental work based on the 3-DOF trilateral teleoperation system consisting of three different manipulators. The experimental results clearly demonstrate the feasibility of the proposed algorithm to achieve high transparency and robust stability in nonlinear single-master-multiple-slave teleoperation system in the presence …
A Novel Membrane Distillation-Thermophilic Bioreactor System: Biological Stability And Trace Organic Compound Removal, Kaushalya Wijekoon, Faisal Hai, Jinguo Kang, William Price, Wenshan Guo, Hao Ngo, Tzahi Cath, Long Nghiem
A Novel Membrane Distillation-Thermophilic Bioreactor System: Biological Stability And Trace Organic Compound Removal, Kaushalya Wijekoon, Faisal Hai, Jinguo Kang, William Price, Wenshan Guo, Hao Ngo, Tzahi Cath, Long Nghiem
Faisal I Hai
The removal of trace organic compounds (TrOCs) by a novel membrane distillation-thermophilic bioreactor (MDBR) system was examined. Salinity build-up and the thermophilic conditions to some extent adversely impacted the performance of the bioreactor, particularly the removal of total nitrogen and recalcitrant TrOCs. While most TrOCs were well removed by the thermophilic bioreactor, compounds containing electron withdrawing functional groups in their molecular structure were recalcitrant to biological treatment and their removal efficiency by the thermophilic bioreactor was low (0-53%). However, the overall performance of the novel MDBR system with respect to the removal of total organic carbon, total nitrogen, and TrOCs …
Thermal Stability And Properties Of Deformation-Processed Cu-Fe In Situ Composites, Keming Liu, Zhengyi Jiang, Jingwei Zhao, Jin Zou, Lei Lu, Deping Lu
Thermal Stability And Properties Of Deformation-Processed Cu-Fe In Situ Composites, Keming Liu, Zhengyi Jiang, Jingwei Zhao, Jin Zou, Lei Lu, Deping Lu
Faculty of Engineering and Information Sciences - Papers: Part A
This paper investigated the thermal stability, tensile strength, and conductivity of deformation-processed Cu-14Fe in situ composites produced by thermo-mechanical processing. The thermal stability was analyzed using scanning electronic microscope and transmission electron microscope. The tensile strength and conductivity were evaluated using tensile-testing machine and micro-ohmmeter, respectively. The Fe fibers in the deformation-processed Cu-14Fe in situ composites undergo edge recession, longitudinal splitting, cylinderization, break-up, and spheroidization during the heat treatment. The Cu matrix experiences recovery, recrystallization, and precipitation phase transition. The tensile strength and conductivity first increase with increasing temperature of heat treatment, reach peak values at different temperatures, and then …
A Semi-Analytical Analysis Of The Stability Of The Reversible Selkov Model, Khaled. Al Noufaey, Timothy R. Marchant, Maureen P. Edwards
A Semi-Analytical Analysis Of The Stability Of The Reversible Selkov Model, Khaled. Al Noufaey, Timothy R. Marchant, Maureen P. Edwards
Faculty of Engineering and Information Sciences - Papers: Part A
Semi-analytical solutions for the reversible Selkov model are developed and used to investigate its static and dynamic stability. A one-dimensional reaction-diffusion cell is considered with all steps of the Selkov reaction modeled. A coupled set of four partial differential equations is obtained for the precursor, reactant, autocatalyst and final product concentrations. The Galerkin method is applied to approximate the spatial structure of the concentrations to obtain a lower-order, ordinary differential equation model, as an approximation to the governing partial differential equations. The semi-analytical model is analysed to obtain steady-state solutions, bifurcation diagrams and parameter maps in which the different types …
Stability Of Carbon Nanotube Yarn Biofuel Cell In Human Body Fluid, Cheong Hoon Kwon, Jae Ah Lee, Young-Bong Choi, Hyug-Han Kim, Geoffrey M. Spinks, Marcio D. Lima, Ray H. Baughman, Seon Jeong Kim
Stability Of Carbon Nanotube Yarn Biofuel Cell In Human Body Fluid, Cheong Hoon Kwon, Jae Ah Lee, Young-Bong Choi, Hyug-Han Kim, Geoffrey M. Spinks, Marcio D. Lima, Ray H. Baughman, Seon Jeong Kim
Faculty of Engineering and Information Sciences - Papers: Part A
High performance with stability, easy-handling electrodes, and biofluid-flow controllable system with mechanical strength of the biofuel cell can be considered as the critical issues for future human body implant. These three challenges are sufficiently considered by using the effective platform regarding the high surface area from multi-walled carbon nanotube-conducting polymer with poly(3,4-ethylenedioxythiophene), and size/shape dependent flexible yarn electrodes for the implantation of biofuel cell. High power biofuel cell of mW cm-2 range in physiological condition (low glucose-containing phosphate buffered saline solution and human blood serum) controlling the stirring degree is also first demonstrated for future implantation in this study. Biofuel …
Stability Enhancement Of Magnetic Levitation Ball System With Two Controlled Electomagnets, Hai Huang, Haiping Du, Weihua Li
Stability Enhancement Of Magnetic Levitation Ball System With Two Controlled Electomagnets, Hai Huang, Haiping Du, Weihua Li
Faculty of Engineering and Information Sciences - Papers: Part A
Magnetic levitation ball system is a highly nonlinear and unstable system. If the system is linearised at the equilibrium point, the achievable balance range of the magnetically levitated ball is very short with one electromagnet. This paper presents an improved magnetic levitation ball system, that contains two electromagnets, where one electromagnet is set above the magnetic ball for pulling, and another one is set under the magnetic ball for pushing. In addition, this paper applies a 2-DOF (degree-of-freedom) PID (proportional-integral-derivative) controller instead of 1-DOF PID for the control of the two electromagnets so that they can work corporately to make …
Influence Of The Nonlinear Gain On The Stability Limit Of A Semiconductor Laser With Optical Feedback, Yuanlong Fan, Yanguang Yu, Jiangtao Xi, Huiying Ye
Influence Of The Nonlinear Gain On The Stability Limit Of A Semiconductor Laser With Optical Feedback, Yuanlong Fan, Yanguang Yu, Jiangtao Xi, Huiying Ye
Faculty of Engineering and Information Sciences - Papers: Part A
This paper presents the results revealing the influence of the nonlinear gain on the stability limit of a semiconductor laser (SL) with external optical feedback (EOF). A new system determinant is derived from the original Lang and Kobayashi (L-K) equations. By making analysis on the locus of the roots of the system determinant, the stability limit of the system is obtained, from which a number of important and interesting phenomenon revealed by the nonlinear gain is uncovered. The correctness of results is verified by numerical simulations.
A Novel Membrane Distillation-Thermophilic Bioreactor System: Biological Stability And Trace Organic Compound Removal, Kaushalya Wijekoon, Faisal Ibney Hai, Jinguo Kang, William Price, Wenshan Guo, Hao H. Ngo, Tzahi Cath, Long Nghiem
A Novel Membrane Distillation-Thermophilic Bioreactor System: Biological Stability And Trace Organic Compound Removal, Kaushalya Wijekoon, Faisal Ibney Hai, Jinguo Kang, William Price, Wenshan Guo, Hao H. Ngo, Tzahi Cath, Long Nghiem
Faculty of Engineering and Information Sciences - Papers: Part A
The removal of trace organic compounds (TrOCs) by a novel membrane distillation-thermophilic bioreactor (MDBR) system was examined. Salinity build-up and the thermophilic conditions to some extent adversely impacted the performance of the bioreactor, particularly the removal of total nitrogen and recalcitrant TrOCs. While most TrOCs were well removed by the thermophilic bioreactor, compounds containing electron withdrawing functional groups in their molecular structure were recalcitrant to biological treatment and their removal efficiency by the thermophilic bioreactor was low (0-53%). However, the overall performance of the novel MDBR system with respect to the removal of total organic carbon, total nitrogen, and TrOCs …
Impact Of Wind Generation Mix On Transient Stability For An Interconnected Power System, Lasantha Meegahapola, Damian Flynn, Jason Kennedy, Tim Littler
Impact Of Wind Generation Mix On Transient Stability For An Interconnected Power System, Lasantha Meegahapola, Damian Flynn, Jason Kennedy, Tim Littler
Dr Lasantha G Meegahapola
The rapid growth of wind generation in many European countries is pushing power systems into uncharted territory. As additional wind generators are installed, the changing generation mix may impact on power system stability. This paper adopts the New England 39 bus system as a test system for transient stability analysis. Thermal generator models are based on a likely future plant mix for existing systems, while varying capacities of fixed-speed induction generators (FSIG) and doubly-fed induction generators (DFIG) are considered. The main emphasis here has been placed on the impact of wind technology mix on inter-area oscillations following transient grid disturbances. …
Impact On Transient And Frequency Stability For A Power System At Very High Wind Penetration, Lasantha Meegahapola, Damian Flynn
Impact On Transient And Frequency Stability For A Power System At Very High Wind Penetration, Lasantha Meegahapola, Damian Flynn
Dr Lasantha G Meegahapola
This paper analyzes the impact on transient and frequency stability for a power system at very high wind penetration (40% wind). Wind penetration is based on the doubly-fed induction generator (DFIG), and a systematic approach has been adopted for wind power integration. A sensitivity analysis has been carried out for each wind integration scenario and for different wind generator loading conditions. A range of fault locations has been selected for stability analysis based on the proximity to synchronous generation and wind farms. The analysis has shown that transient stability performance is subject to fault location in the network, especially when …
Transient Stability Analysis Of A Power System With High Wind Penetration, Lasantha Meegahapola, Damian Flynn, Tim Littler
Transient Stability Analysis Of A Power System With High Wind Penetration, Lasantha Meegahapola, Damian Flynn, Tim Littler
Dr Lasantha G Meegahapola
This paper presents transient stability analysis for a power system with high wind penetration. The transient stability has been evaluated based on two stability criteria: rotor angle stability and voltage stability. A modified IEEE-14 bus system has been used as the main study network and simulations have been conducted at several wind power penetration levels, defined as a fraction of total system generation. A wide range of scenarios have been presented based on the wind farm voltage at the point of connection, i.e. low voltage (LV) distribution level and high voltage (HV) transmission level, and the type of wind generator …
Active Use Of Dfig Based Wind Farms For Transient Stability Improvement During Grid Disturbances, Lasantha Meegahapola, Damian Flynn, Jason Kennedy, Tim Littler
Active Use Of Dfig Based Wind Farms For Transient Stability Improvement During Grid Disturbances, Lasantha Meegahapola, Damian Flynn, Jason Kennedy, Tim Littler
Dr Lasantha G Meegahapola
The doubly-fed induction generator (DFIG) now represents the dominant technology in wind turbine design. One consequence of this is limited damping and inertial response during transient grid disturbances. A 'decoupled' strategy is therefore proposed to operate the DFIG grid-side converter (GSC) as a static synchronous compensator (STATCOM) during a fault, supporting the local voltage, while the DFIG operates as a fixed-speed induction generator (FSIG) providing an inertial response. The modeling aspects of the decoupled control strategy, the selection of protection control settings, the significance of the fault location and operation at sub- and super-synchronous speeds are analyzed in detail. In …
Capability Curve Based Enhanced Reactive Power Control Strategy For Stability Enhancement And Network Voltage Management, Lasantha Meegahapola, Tim Littler, Sarath Perera
Capability Curve Based Enhanced Reactive Power Control Strategy For Stability Enhancement And Network Voltage Management, Lasantha Meegahapola, Tim Littler, Sarath Perera
Dr Lasantha G Meegahapola
Reactive power has become a vital resource in modern electricity networks due to increased penetration of distributed generation. This paper examines the extended reactive power capability of DFIGs to improve network stability and capability to manage network voltage profile during transient faults and dynamic operating conditions. A coordinated reactive power controller is designed by considering the reactive power capabilities of the rotor-side converter (RSC) and the grid-side converter (GSC) of the DFIG in order to maximise the reactive power support from DFIGs. The study has illustrated that, a significant reactive power contribution can be obtained from partially loaded DFIG wind …
Capability Curve Based Enhanced Reactive Power Control Strategy For Stability Enhancement And Network Voltage Management, Lasantha Meegahapola, Tim Littler, Sarath Perera
Capability Curve Based Enhanced Reactive Power Control Strategy For Stability Enhancement And Network Voltage Management, Lasantha Meegahapola, Tim Littler, Sarath Perera
Faculty of Engineering and Information Sciences - Papers: Part A
Reactive power has become a vital resource in modern electricity networks due to increased penetration of distributed generation. This paper examines the extended reactive power capability of DFIGs to improve network stability and capability to manage network voltage profile during transient faults and dynamic operating conditions. A coordinated reactive power controller is designed by considering the reactive power capabilities of the rotor-side converter (RSC) and the grid-side converter (GSC) of the DFIG in order to maximise the reactive power support from DFIGs. The study has illustrated that, a significant reactive power contribution can be obtained from partially loaded DFIG wind …
Addressing Retained Austenite Stability In Advanced High Strength Steels, Elena V. Pereloma, Azdiar A. Gazder, Ilana B. Timokhina
Addressing Retained Austenite Stability In Advanced High Strength Steels, Elena V. Pereloma, Azdiar A. Gazder, Ilana B. Timokhina
Faculty of Engineering and Information Sciences - Papers: Part A
Advances in the development of new high strength steels have resulted in microstructures containing significant volume fractions of retained austenite. The transformation of retained austenite to martensite upon straining contributes towards improving the ductility. However, in order to gain from the above beneficial effect, the volume fraction, size, morphology and distribution of the retained austenite need to be controlled. In this regard, it is well known that carbon concentration in the retained austenite is responsible for its chemical stability, whereas its size and morphology determines its mechanical stability. Thus, to achieve the required mechanical properties, control of the processing parameters …
Robust Yaw Moment Control For Vehicle Handling And Stability, Haiping Du, Nong Zhang, Wade Smith
Robust Yaw Moment Control For Vehicle Handling And Stability, Haiping Du, Nong Zhang, Wade Smith
Faculty of Engineering and Information Sciences - Papers: Part A
This paper presents a robust yaw moment controller design approach for improving vehicle handling and stability. With considering the parameter-varying property of tyre cornering stiffness in extreme handling situations, a linear parameter-varying (LPV) model in polytopic form is constructed to represent the nonlinear characteristics of tyres. A yaw moment controller is then designed for the LPV model which aims at optimising the tracking performance on both yaw rate and sideslip angle with respect to their targets. The conditions for designing such a controller are derived in terms of linear matrix inequalities (LMIs). Numerical simulations on a nonlinear vehicle model are …
Experimental Investigation Of A Hydraulically Interconnected Suspension In Vehicle Dynamics And Stability Control, Lifu Wang, Nong Zhang, Haiping Du
Experimental Investigation Of A Hydraulically Interconnected Suspension In Vehicle Dynamics And Stability Control, Lifu Wang, Nong Zhang, Haiping Du
Faculty of Engineering and Information Sciences - Papers: Part A
Mainly motivated by developing cost-effective vehicle anti-roll systems, hydraulically interconnected suspension has been studied in the past decade to replace anti-roll bars. It has been proved theoretically and practically that hydraulic suspensions have superior anti-roll ability over anti-roll bars, and therefore they have achieved commercial success in racing cars and luxury sports utility vehicles (SUVs). However, since vehicle is a highly coupled complex system, it is necessary to investigate/evaluate the hydraulic-suspension-fitted-vehicle's dynamic performance in other aspects, apart from anti-roll ability, such as ride comfort, lateral stability, etc. This paper presents an experimental investigation of a SUV fitted with a hydraulically …
Comparison Of Thermal Stability In Max211 And 312 Phases, Wei Kong Pang, It-Meng Low, B H. O'Connor, Andrew J. Studer, Vanessa Peterson, Zheng-Ming Sun, J P. Palmquist
Comparison Of Thermal Stability In Max211 And 312 Phases, Wei Kong Pang, It-Meng Low, B H. O'Connor, Andrew J. Studer, Vanessa Peterson, Zheng-Ming Sun, J P. Palmquist
Faculty of Engineering and Information Sciences - Papers: Part A
The susceptibility of four MAX phases (Ti2AlC, Cr2AlC, Ti3AlC2, and Ti3SiC2) to high-temperature thermal dissociation in vacuum has been investigated using in-situ neutron diffraction.
Effect Of Microstructure On The Stability Of Retained Austenite In Transformation-Induced-Plasiticity Steels, I B. Timokhina, P D. Hodgson, E V. Pereloma
Effect Of Microstructure On The Stability Of Retained Austenite In Transformation-Induced-Plasiticity Steels, I B. Timokhina, P D. Hodgson, E V. Pereloma
Faculty of Engineering and Information Sciences - Papers: Part A
Two Fe-0.2C-1.55Mn-1.5Si (in wt pct) steels, with and without the addition of 0.039Nb (in wt pct), were studied using laboratory rolling-mill simulations of controlled thermomechanical processing. The microstructures of all samples were characterized by optical metallography, X-ray diffraction (XRD), and transmission electron microscopy (TEM). The microstructural behavior of phases under applied strain was studied using a heat-tinting technique. Despite the similarity in the microstructures of the two steels (equal amounts of polygonal ferrite, carbide-free bainite, and retained austenite), the mechanical properties were different. The mechanical properties of these transformation-induced-plasticity (TRIP) steels depended not only on the individual behavior of all …
Network Reconfiguration For Enhancement Of Voltage Stability In Distribution Networks, Kashem M. Muttaqi, Velappa Ganapathy, G G. Jasmon
Network Reconfiguration For Enhancement Of Voltage Stability In Distribution Networks, Kashem M. Muttaqi, Velappa Ganapathy, G G. Jasmon
Faculty of Engineering and Information Sciences - Papers: Part A
Network reconfiguration is performed by altering the topological structure of distribution feeders. By reconfiguring the network, voltage stability can be maximised for a particular set of loads in distribution systems. A new algorithm is formulated for enhancement of voltage stability by network reconfiguration. Initially, a certain number of switching combinations is generated using the combination of tie and its two neighbouring switches, and the best combination of switches for maximising the voltage stability in the network among them is determined. Then the search is extended by considering the branches next to the open-branches of the best configuration one by one …
Instrumentation For Slope Stability - Experience From An Urban Area, P N. Flentje, R N. Chowdhury
Instrumentation For Slope Stability - Experience From An Urban Area, P N. Flentje, R N. Chowdhury
Faculty of Engineering and Information Sciences - Papers: Part A
This paper describes the monitoring of several existing landslides in an urban area near Wollongong in the state of New South Wales, Australia. A brief overview of topography and geology is given and reference is made to the types of slope movement, processes and causal factors. Often the slope movements are extremely slow and imperceptible to the eye, and catastrophic failures are quite infrequent. However, cumulative movements at these slower rates do, over time, cause considerable distress to structures and disrupt residential areas and transport routes. Inclinometers and piezometers have been installed at a number of locations and monitoring of …