Open Access. Powered by Scholars. Published by Universities.®
- Discipline
- Institution
- Publication
- Publication Type
- File Type
Articles 1 - 30 of 40
Full-Text Articles in Engineering
Simultaneous Activated Carbon Adsorption Within A Membrane Bioreactor For An Enhanced Micropollutant Removal, Xueqing Li, Faisal I. Hai, Long Nghiem
Simultaneous Activated Carbon Adsorption Within A Membrane Bioreactor For An Enhanced Micropollutant Removal, Xueqing Li, Faisal I. Hai, Long Nghiem
Long D Nghiem
Significant adsorption of sulfamethoxazole and carbamazepine to powdered activated carbon (PAC) was confirmed by a series of adsorption tests. In contrast, adsorption of these micropollutants to the sludge was negligible. The removal of these compounds in membrane bioreactor (MBR) was dependent on their hydrophobicity and loading as well as the PAC dosage. Sulfamethoxazole exhibited better removal rate during operation under no or low (0.1 g/L) PAC dosage. When the PAC concentration in MBR was raised to 1.0 g/L, a sustainable and significantly improved performance in the removal of both compounds was observed – the removal efficiencies of sulfamethoxazole and carbamazepine …
Treatment Of Coal Seam Gas Produced Water For Beneficial Use In Australia: A Review Of Best Practices, Long Nghiem, Ting Ren, Najdat Aziz, Ian Porter, Gyanendra Regmi
Treatment Of Coal Seam Gas Produced Water For Beneficial Use In Australia: A Review Of Best Practices, Long Nghiem, Ting Ren, Najdat Aziz, Ian Porter, Gyanendra Regmi
Long D Nghiem
There has been an exponential increase in both the production and exploration of coal seam gas (CSG) in Australia and many other regions in the world. A major issue associated with the production of CSG is the management of produced water. CSG is usually mixed with water in the coal seam, to recover the gas, the water must be first extracted from the coal seam to reduce pressure. This water — known as co-produced water or CSG water — is typically quite saline, large in volume and may contain heavy metals and other trace elements of concern. The management of …
Membrane Bioreactor Technology For Decentralised Wastewater Treatment, Nichanan Tadkaew, Long Nghiem, Muttucumaru Sivakumar
Membrane Bioreactor Technology For Decentralised Wastewater Treatment, Nichanan Tadkaew, Long Nghiem, Muttucumaru Sivakumar
Long D Nghiem
Driven by stricter environmental regulations and legalisation on wastewater discharge and shrinking fresh water resources, water treatment has become an area of significant concern while at the same time there is a growing interest in utilising non-traditional water resources by means of water reclamation and water recycling.
Transmitter Diversity Antenna Selection Techniques For Wireless Channels Utilizing Differential Space-Time Block Codes, Jennifer Seberry, A. Mertins, Tadeusz Wysocki, Le Chung Tran
Transmitter Diversity Antenna Selection Techniques For Wireless Channels Utilizing Differential Space-Time Block Codes, Jennifer Seberry, A. Mertins, Tadeusz Wysocki, Le Chung Tran
Dr Le Chung Tran
No abstract provided.
Contextual Effects In Modeling For Small Domain Estimation, Mohammad-Reza Namazi-Rad, David G. Steel
Contextual Effects In Modeling For Small Domain Estimation, Mohammad-Reza Namazi-Rad, David G. Steel
Professor David Steel
Many different Small Area Estimation (SAE) methods have been proposed to overcome the challenge of findingreliable estimates for small domains. Often, the required data for various research purposes are available at differentlevels of aggregation. Based on the available data, individual-level or aggregated-level models are used in SAE.However, parameter estimates obtained from individual and aggregated level analysis may be different, in practice.This may happen due to some substantial contextual or area-level effects in the covariates which may be misspecifiedin individual-level analysis. If small area models are going to be interpretable in practice, possible contextualeffects should be included. Ignoring these effects leads …
Linear Predictive Perceptual Filtering For Acoustic Vector Sensors: Exploiting Directional Recordings For High Quality Speech Enhancement, Muawiyath Shujau, Christian Ritz, Ian Burnett
Linear Predictive Perceptual Filtering For Acoustic Vector Sensors: Exploiting Directional Recordings For High Quality Speech Enhancement, Muawiyath Shujau, Christian Ritz, Ian Burnett
Dr Muawiyath Shujau
This paper investigates the performance of a new technique for speech enhancement which combines Linear Predictive (LP) spectrum-based perceptual filtering to the recordings obtained from an Acoustic Vector Sensor (AVS). The technique takes advantage of the directional polar responses of the AVS to obtain a significantly more accurate representation of the LP spectrum of a target speech signal in the presence of noise when compared to single channel, omni-directional recordings. Comparisons between the speech quality obtained from the proposed technique and existing beamforming-based speech enhancement techniques for the AVS are made through Perceptual Evaluation of Speech Quality (PESQ) tests and …
Coupling Biophysical And Socioeconomic Models For Coral Reef Systems In Quintana Roo, Mexican Caribbean, Deborah Cleland, Jess Melbourne-Thomas, Craig Johnson, Pascal Perez, Jeremy Eustache, Elizabeth Fulton
Coupling Biophysical And Socioeconomic Models For Coral Reef Systems In Quintana Roo, Mexican Caribbean, Deborah Cleland, Jess Melbourne-Thomas, Craig Johnson, Pascal Perez, Jeremy Eustache, Elizabeth Fulton
Professor Pascal Perez
No abstract provided.
Verification Of The Plan Dosimetry For High Dose Rate Brachytherapy Using Metal-Oxide-Semiconductor Field Effect Transistor Detectors, Zhen-Yu Qi, Xiao-Wu Deng, Shao-Min Huang, Jie Lu, Michael Lerch, Dean Cutajar, Anatoly Rosenfeld
Verification Of The Plan Dosimetry For High Dose Rate Brachytherapy Using Metal-Oxide-Semiconductor Field Effect Transistor Detectors, Zhen-Yu Qi, Xiao-Wu Deng, Shao-Min Huang, Jie Lu, Michael Lerch, Dean Cutajar, Anatoly Rosenfeld
Dean Cutajar
The feasibility of a recently designed metal–oxide–semiconductor field effect transistor (MOSFET) dosimetry system for dose verification of high dose rate (HDR) brachytherapy treatment planning was investigated. MOSFET detectors were calibrated with a 0.6 cm3 NE-2571 Farmer-type ionization chamber in water. Key characteristics of the MOSFET detectors, such as the energy dependence, that will affect phantom measurements with HDR 192Ir sources were measured. The MOSFET detector was then applied to verify the dosimetric accuracy of HDR brachytherapy treatments in a custom-made water phantom. Three MOSFET detectors were calibrated independently, with the calibration factors ranging from 0.187 to 0.215 cGy∕mV. A distance …
In Vivo Verification Of Superficial Dose For Head And Neck Treatments Using Intensity-Modulated Techniques, Zhen-Yu Qi, Xiao-Wu Deng, Shao-Min Huang, Li Zhang, Zhi-Chun He, X. Allen Li, Ian Kwan, Michael Lerch, Dean Cutajar, Peter Metcalfe, Anatoly Rosenfeld
In Vivo Verification Of Superficial Dose For Head And Neck Treatments Using Intensity-Modulated Techniques, Zhen-Yu Qi, Xiao-Wu Deng, Shao-Min Huang, Li Zhang, Zhi-Chun He, X. Allen Li, Ian Kwan, Michael Lerch, Dean Cutajar, Peter Metcalfe, Anatoly Rosenfeld
Dean Cutajar
Skin dose is one of the key issues for clinical dosimetry in radiation therapy. Currently planning computer systems are unable to accurately predict dose in the buildup region, leaving ambiguity as to the dose levels actually received by the patient’s skin during radiotherapy. This is one of the prime reasons why in vivo measurements are necessary to estimate the dose in the buildup region. A newly developed metal-oxide-semiconductor-field-effect-transistor (MOSFET) detector designed specifically for dose measurements in rapidly changing dose gradients was introduced for accurate in vivo skin dosimetry. The feasibility of this detector for skin dose measurements was verified in …
Silicon/Single-Walled Carbon Nanotube Composite Paper As A Flexible Anode Material For Lithium Ion Batteries, Shulei Chou, Yue Zhao, Jiazhao Wang, Zhixin Chen, Hua-Kun Liu, S. X. Dou
Silicon/Single-Walled Carbon Nanotube Composite Paper As A Flexible Anode Material For Lithium Ion Batteries, Shulei Chou, Yue Zhao, Jiazhao Wang, Zhixin Chen, Hua-Kun Liu, S. X. Dou
Shulei Chou
Flexible silicon/single-walled carbon nanotube (Si/SWCNT) composite paper was prepared using the pulsed laser deposition (PLD) method to deposit Si onto SWCNT paper. In the composite, Si mainly shows nanoworm-like morphology. Increasing deposition time results in an increased amount of Si microspheres. Electrochemical measurements show that the capacity of the composite paper is improved by the presence of Si. The Si/SWCNT composite with only 2.2% Si shows a capacity of 163 mA h g−1 at a current density of 25 mA g−1 up to 50 cycles, which is more than 60% improvement of the capacity of pristine CNT paper. The Si …
Rapid Synthesis Of Li4ti5o12 Microspheres As Anode Materials And Its Binder Effect For Lithium-Ion Battery, Shulei Chou, Jiazhao Wang, Hua Liu, S. Dou
Rapid Synthesis Of Li4ti5o12 Microspheres As Anode Materials And Its Binder Effect For Lithium-Ion Battery, Shulei Chou, Jiazhao Wang, Hua Liu, S. Dou
Shulei Chou
Li4Ti5O12 microspheres composed of nanoflakes were synthesized within 1 h by a combination of a microwave-assisted hydrothermal method and a microwave postannealing process. The Li4Ti5O12 microspheres were characterized by X-ray diffraction, Brunauer–Emmett–Teller N2 adsorption, scanning electron microscopy, Raman spectroscopy, and transmission electron microscopy. Sodium carboxymethyl cellulose (CMC) was also investigated as a low-cost green binder. The electrochemical tests, including constant current charge–discharge, cyclic voltammetry, and electrochemical impedance spectroscopy, demonstrated that the electrode using CMC as binder had better high-rate capability than the one with polyvinylidene fluoride (PVDF) binder. The electrode using CMC and PVDF as binder had the same lithium …
Silver-Coated Tio2 Nanostructured Anode Materials For Lithium Ion Batteries, - Md. Mokhlesur Rahman, Jiazhao Wang, David Wexler, Yuyuan Zhang, Xinjun Li, Shulei Chou, Hua Liu
Silver-Coated Tio2 Nanostructured Anode Materials For Lithium Ion Batteries, - Md. Mokhlesur Rahman, Jiazhao Wang, David Wexler, Yuyuan Zhang, Xinjun Li, Shulei Chou, Hua Liu
Shulei Chou
Anatase TiO2 nanoribbons/nanotubes (TiO2-NRTs) have been synthesised successfully via a reflux method followed by drying in a vacuum oven, and then, silver-coated TiO2 NRTs (Ag/TiO2-NRTs) were prepared by coating silver particles onto the TiO2-NRTs surface by the traditional silver mirror reaction. The physical properties of the synthesised products were examined in detail using X-ray diffraction, field emission gun scanning electron microscopy, energy-dispersive X-ray spectroscopy, and transmission electron microscopy, respectively. The results indicated that the Ag nanoparticles were uniformly deposited on the surface of the TiO2 nanoribbons/nanotubes. The electrochemical properties were investigated …
Nanocrystalline Porous A-Life02-C Composite-An Environmentally Friendly Cathode For The Lithium-Ion Battery, Md Mokhlesur Rahman, Jiazhao Wang, Mohd Faiz Hassan, Shulei Chou, Zhixin Chen, Hua Liu
Nanocrystalline Porous A-Life02-C Composite-An Environmentally Friendly Cathode For The Lithium-Ion Battery, Md Mokhlesur Rahman, Jiazhao Wang, Mohd Faiz Hassan, Shulei Chou, Zhixin Chen, Hua Liu
Shulei Chou
A novel nanocrystalline porous α-LiFeO2–C composite with a high surface area of around 115 m2 g−1 has been synthesized by a simple molten salt method, followed by a carbon coating process. The structure and morphology were confirmed by X-ray diffraction, field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). FE-SEM observations demonstrated that the morphology consists of α-LiFeO2–C nanoclusters composed of very tiny nanoparticles joined together by a porous architecture. TEM investigations revealed that amorphous carbon was incorporated into the pores among the nanoparticles and that some nanoparticles were covered by a thin layer of carbon as well. …
Electrochemical Deposition Of Porous Vox And Mno2 Nanowires On Stainless Steel Mesh For Flexible Supercapacitors, Shulei Chou, Jiazhao Wang, Hua Liu, S Dou
Electrochemical Deposition Of Porous Vox And Mno2 Nanowires On Stainless Steel Mesh For Flexible Supercapacitors, Shulei Chou, Jiazhao Wang, Hua Liu, S Dou
Shulei Chou
Porous vanadium oxide (VOx) and MnO2 nanowires were synthesized by an electrochemical deposition method using stainless steel mesh as substrate. The as-prepared porous VOx and MnO2 nanowire films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Raman spectroscopy. The cyclic voltammetry (CV) results show that the MnO2 nanowire film shows specific capacitance of 195, 170, 158, and 91 F g-1 at scan rates of 5, 10, 20, and 50 mV s-1, respectively. The porous VOx film displays specific capacitance of 152, 124, 99, and 76 F g …
Electrodeposition Of Mno2 Nanowires On Carbon Nanotube Paper As Free-Standing, Flexible Electrode For Supercapacitors, Shulei Chou, Jia-Zhao Wang, Sau-Yen Chew, Hua Liu, S Dou
Electrodeposition Of Mno2 Nanowires On Carbon Nanotube Paper As Free-Standing, Flexible Electrode For Supercapacitors, Shulei Chou, Jia-Zhao Wang, Sau-Yen Chew, Hua Liu, S Dou
Shulei Chou
MnO2 nanowires were electrodeposited onto carbon nanotube (CNT) paper by a cyclic voltametric technique. The as-prepared MnO2 nanowire/CNT composite paper (MNCCP) can be used as a flexible electrode for electrochemical supercapacitors. Electrochemical measurements showed that the MNCCP electrode displayed specific capacitances as high as 167.5 F g-1 at a current density of 77 mA g-1. After 3000 cycles, the composite paper can retain more than 88% of initial capacitance, showing good cyclability. The CNT paper in the composite acted as a good conductive and active substrate for flexible electrodes in supercapacitors, and the nanowire structure of the MnO2 could facilitate …
Nickel Sulfide Cathode In Combination With An Ionic Liquid-Based Electrolyte For Rechargeable Lithium Batteries, Jiazhao Wang, Shulei Chou, Sau Yen Chew, Jiazeng Sun, Maria Forsyth, Douglas Macfarlane, Hua Liu
Nickel Sulfide Cathode In Combination With An Ionic Liquid-Based Electrolyte For Rechargeable Lithium Batteries, Jiazhao Wang, Shulei Chou, Sau Yen Chew, Jiazeng Sun, Maria Forsyth, Douglas Macfarlane, Hua Liu
Shulei Chou
Nickel sulfides, pure Ni3S2 and a mixture of Ni7S6-NiS, were synthesized through a solvothermal process. The nickel sulphide powders were characterised by X-ray diffraction, scanning electron microscopy, and electrochemical testing. The results showed that the capacity of NiS-Ni7S6 is much higher than that of Ni3S2, when used as the cathode in a lithium cell with an organic solvent-based electrolyte, 1 M lithium bis (trifluoromethanesulfonyl)amide (LiNTf2) in poly(ethylene glycol) dimethyl either 500. The NiS-Ni7S6 electrodes were also tested with an ionic liquid electrolyte consisting of 1 M LiNTf2 in N-methyl-N-propyl pyrrolidinium bis(trifioromethanesulfonyl)amide ([C3mpyr][NTf2]) to compare with organic-solvent based electrolytes. The result …
Electrochemical Deposition Of Porous Co3o4 Nanostructured Thin Film For Lithium-Ion Battery, Shulei Chou, Jiazhao Wang, Hua Liu, S. Dou
Electrochemical Deposition Of Porous Co3o4 Nanostructured Thin Film For Lithium-Ion Battery, Shulei Chou, Jiazhao Wang, Hua Liu, S. Dou
Shulei Chou
Porous Co3O4 nanostructured thin films are electrodeposited by controlling the concentration of Co(NO3)2 aqueous solution on nickel sheets, and then sintered at 300C for 3 h. The as-prepared thin films are characterised by thermogravimetric analysis (TGA), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The electrochemical measurements show that the highly porous Co3O4 thin film with the highest electrochemically active specific surface area (68.64 m2 g-1) yields the best electrochemical performance compared with another, less-porous film and with a non-porous film. The highest specific capacity (513 mAh g-1 after 50 cycles) is obtained from the thinnest film with Co3O4 loaded …
The Compatibility Of Transition Metal Oxide/Carbon Composite Anode And Ionic Liquid Electrolyte For The Lithium-Ion Battery, Shulei Chou, Lin Lu, Jiazhao Wang, Md Mokhlesur Rahman, Chao Zhong, Hua Liu
The Compatibility Of Transition Metal Oxide/Carbon Composite Anode And Ionic Liquid Electrolyte For The Lithium-Ion Battery, Shulei Chou, Lin Lu, Jiazhao Wang, Md Mokhlesur Rahman, Chao Zhong, Hua Liu
Shulei Chou
Three types of transition metal oxide/carbon composites including Fe2O3/C, NiO/C and CuO/Cu2O/C synthesized via spray pyrolysis were used as anode for lithium ion battery application in conjunction with two types of ionic liquid: 1 M LiN(SO2CF3)2 (LiTFSI) in 1-ethyl-3-methyl-imidazolium bis(fluorosulfonlyl)imide (EMI-FSI) or 1-methyl-1-propylpyrrolidinium bis(fluorosulfonyl)imide (Py13-FSI). From the electrochemical measurements, the composite electrodes using Py13-FSI as electrolyte show much better electrochemical performance than those using EMI-FSI as electrolyte in terms of reversibility. The Fe2O3/C composite shows the highest specific capacity and the best capacity retention (425 mAh g−1) under a current density of 50 mA g−1 for up to 50 cycles, …
Sno2-Coated Multiwall Carbon Nanotube Composite Anode Materials For Rechargeable Lithium-Ion Batteries, Lukman Noerochim, Jiazhao Wang, Shulei Chou, Huijun Li, Hua Liu
Sno2-Coated Multiwall Carbon Nanotube Composite Anode Materials For Rechargeable Lithium-Ion Batteries, Lukman Noerochim, Jiazhao Wang, Shulei Chou, Huijun Li, Hua Liu
Shulei Chou
SnO2-coated multiwall carbon nanotube (MWCNT) nanocomposites were synthesized by a facile hydrothermal method. The as-prepared nanocomposites were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and thermogravimetric analysis (TGA). The SnO2/MWCNT composites, when combined with carboxymethyl cellulose (CMC) as a binder, show excellent cyclic retention, with the high specific capacity of 473 mAh g−1 beyond 100 cycles, much greater than that of the bare SnO2 which was also prepared by the hydrothermal method in the absence of MWCNTs. The enhanced capacity retention could be mainly attributed to …
Electrochemical Deposition Of Porous Co(Oh)2 Nanoflake Films On Stainless Steel Mesh For Flexible Supercapacitors, Shulei Chou, Jiazhao Wang, Hua-Kun Liu, S. X. Dou
Electrochemical Deposition Of Porous Co(Oh)2 Nanoflake Films On Stainless Steel Mesh For Flexible Supercapacitors, Shulei Chou, Jiazhao Wang, Hua-Kun Liu, S. X. Dou
Shulei Chou
Flexible porous Co(OH)2 nanoflake films were prepared by galvanostatic electrodeposition on lightweight and inexpensive stainless steel mesh. The as-prepared porous Co(OH)2 nanoflake films were characterized by X-ray diffraction, thermogravimetric analysis, and scanning electron microscopy. Electrochemical tests including cyclic voltammetry, constant current charge-discharge, and electrochemical impedance spectroscopy were also used to investigate the electrochemical performance. The results show that the highest capacitance is 609.4 F g-1, the specific capacitance decreases by less than 5% as the mass loading of Co(OH)2 increases by more than 340%, and the specific capacitance only decreases by less than 15% when the current densities increase up …
Highly Flexible And Bendable Free-Standing Thin Film Polymer For Battery Application, Jiazhao Wang, Shulei Chou, Hao Liu, Guoxiu Wang, Chao Zhong, Sau Yen Chew, Hua Liu
Highly Flexible And Bendable Free-Standing Thin Film Polymer For Battery Application, Jiazhao Wang, Shulei Chou, Hao Liu, Guoxiu Wang, Chao Zhong, Sau Yen Chew, Hua Liu
Shulei Chou
Highly flexible and bendable free-standing polypyrrole (PPy) films were prepared using the electrochemical polymerization method. The paper-like films are soft, lightweight, mechanically robust, and highly electrically conductive. The morphologies and electrochemical behaviour of the free-standing pure PPy films were affected by the electrochemical polymerization conditions. The free-standing films show promise as cathodes for flexible and bendable batteries.
Basic Molten Salt Process-A New Route For Synthesis Of Nanocrystalline Li4ti5o12-Tio2 Anode Material For Li-Ion Batteries Using Eutectic Mixture Of Lino3-Lioh-Li2o2, Md Mokhlesur Rahman, Jiazhao Wang, Mohd Hassan, Shulei Chou, David Wexler, Hua Liu
Basic Molten Salt Process-A New Route For Synthesis Of Nanocrystalline Li4ti5o12-Tio2 Anode Material For Li-Ion Batteries Using Eutectic Mixture Of Lino3-Lioh-Li2o2, Md Mokhlesur Rahman, Jiazhao Wang, Mohd Hassan, Shulei Chou, David Wexler, Hua Liu
Shulei Chou
A nanocrystalline Li4Ti5O12–TiO2 duplex phase has been synthesized by a simple basic molten salt process (BMSP) using an eutectic mixture of LiNO3–LiOH–Li2O2 at 400–500 °C. The microstructure and morphology of the Li4Ti5O12–TiO2 product are characterized by means of X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM). The sample prepared by heat-treating at 300 °C for 3 h (S-1) reveals dense agglomerates of ultra-fine nanocrystalline Li4Ti5O12; with heat treatment at …
Spray Pyrolyzed Nio-C Nanocomposite As An Anode Material For The Lithium-Ion Battery With Enhanced Capacity Retention, - Md. Mokhlesur Rahman, Shulei Chou, Chao Zhong, Jiazhao Wang, David Wexler, Hua Liu
Spray Pyrolyzed Nio-C Nanocomposite As An Anode Material For The Lithium-Ion Battery With Enhanced Capacity Retention, - Md. Mokhlesur Rahman, Shulei Chou, Chao Zhong, Jiazhao Wang, David Wexler, Hua Liu
Shulei Chou
NiO–C nanocomposite was prepared by a spray pyrolysis method using a mixture of Ni(NO3)2 and citric acid solution at 600 °C. The microstructure and morphology of the NiO–C composite were characterized by means of X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS) mapping, and thermogravimetric analysis (TGA). The results showed that the NiO nanoparticles were surrounded by amorphous carbon. Electrochemical tests demonstrated that the NiO–C nanocomposites exhibited better capacity retention (382 mAh g− 1 for 50 cycles) than that of pure NiO (141 mAh g− 1 for 50 cycles), which was also prepared by spray pyrolysis using …
Rapid Synthesis Of Binary -Nisb-Nis By Microwave Autoclave For Rechargeable Lithium Batteries, Nurul Idris, - Md. Mokhlesur Rahman, Shulei Chou, Jiazhao Wang, David Wexler, Hua Liu
Rapid Synthesis Of Binary -Nisb-Nis By Microwave Autoclave For Rechargeable Lithium Batteries, Nurul Idris, - Md. Mokhlesur Rahman, Shulei Chou, Jiazhao Wang, David Wexler, Hua Liu
Shulei Chou
To reduce the reaction time, electrical energy consumption, and cost, binary α-NiS–β-NiS has been synthesized by a rapid, one-pot, hydrothermal autoclave microwave method within 15 min at temperatures of 160–180 °C. The microstructure and morphology of the α-NiS–β-NiS products were characterized by means of X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM). At 140 °C, pure hexagonal NiAs-type α-NiS phase was identified from the XRD patterns. With increasing reaction temperature (160–180 °C), the XRD evidence indicates that an increasing fraction of rhombohedral millerite-like β-NiS is formed as a secondary phase. The α-NiS–β-NiS sample synthesized …
Reducing Wave-Based Teleoperator Reflections For Unknown Environments, Laurence Bate, Christopher Cook, Zheng Li
Reducing Wave-Based Teleoperator Reflections For Unknown Environments, Laurence Bate, Christopher Cook, Zheng Li
Laurence Bate Dr.
Wave variables guarantee stability for delayed teleoperation. They also introduce reflections which can prove very disorientating for an operator. This paper presents a new method for reducing the wave reflections when operating in unknown environments. The new method does not only guarantee stability but also laboratory experiments show it also reduces wave reflections allowing for improved velocity tracking and force feedback in complex and unknown operating environments.
Experimental Evaluation Of Adaptive And Variable Structure Control Of Piezoelectric Actuation Systems For Micro/Nano Manipulation, Hwee Choo Liaw, Bijan Shirinzadeh, Denny Oetomo, Gursel Alici
Experimental Evaluation Of Adaptive And Variable Structure Control Of Piezoelectric Actuation Systems For Micro/Nano Manipulation, Hwee Choo Liaw, Bijan Shirinzadeh, Denny Oetomo, Gursel Alici
Gursel Alici
This paper proposes and evaluates an adaptive technique and a variable structure control approach for piezoelectric actuation systems to track specified motion trajectories. The proposed control methodologies are formulated to accommodate unknown or uncertain system parameters, nonlinearities including the hysteresis effect, and external disturbances in the piezoelectric actuation systems without any form of feed-forward compensation. In this study, both control methodologies are demonstrated to possess a promising motion tracking ability experimentally. In comparison, the variable structure control approach is evaluated to be superior to the adaptive technique in the motion tracking control. With the ability to track motion trajectories under …
Special Class Of Positive Definite Functions For Formulating Adaptive Micro/Nano Manipulator Control, Hwee Choo Liaw, Denny Oetomo, Gursel Alici, Bijan Shirinzadeh
Special Class Of Positive Definite Functions For Formulating Adaptive Micro/Nano Manipulator Control, Hwee Choo Liaw, Denny Oetomo, Gursel Alici, Bijan Shirinzadeh
Gursel Alici
This paper presents a special class of positive definite functions for the formulation of adaptive control strategies, specifically in the research of an effective control algorithm for piezoelectric actuation systems in micro/nano manipulation. To deal with the control problems of unknown system parameters, nonlinear hysteresis effects, and disturbances in the piezoelectric actuation systems, an adaptive control methodology is proposed. Using the saturation function derived from a positive definite function to formulate the control methodology, the closed-loop system stability can be guaranteed. Furthermore, the control methodology is proposed to track a desired motion trajectory in position, velocity, and acceleration. In this …
Contact State Determination For Robotic-Based Cylindrical Pair Height Adjustment Under Dynamic Conditions, Prasan I. De Waas Tilakaratna, Bijan Shirinzadeh, Gursel Alici
Contact State Determination For Robotic-Based Cylindrical Pair Height Adjustment Under Dynamic Conditions, Prasan I. De Waas Tilakaratna, Bijan Shirinzadeh, Gursel Alici
Gursel Alici
This paper investigates fine motion strategies associated with the height adjustment manipulations of a cylindrical pair which can be utilised in dynamic assembly and reconfigurable workholding systems. The outer link of the cylindrical pair is held by the end-effector of a 6DOF serial articulated robot. The environment which holds the inner link can be dynamic. Formulations capable of identifying the type of contact between the links and parameters vital for control purposes based on the force and torque data provided by a wrist mounted F/T sensor are established for a generic spatial case. Experimental results indicate that the established methodology …
Robust Control Framework For Piezoelectric Actuation Systems In Micro/Nano Manipulation, Hwee Choo Liaw, Denny Oetomo, Bijan Shirinzadeh, Gursel Alici
Robust Control Framework For Piezoelectric Actuation Systems In Micro/Nano Manipulation, Hwee Choo Liaw, Denny Oetomo, Bijan Shirinzadeh, Gursel Alici
Gursel Alici
Micro/nano manipulation has been identified as one of the key enabling technologies for many emerging challenges. Within this scope, piezoelectric actuators have played major roles in achieving the required nano-resolution motion. This paper proposes a robust control framework for piezoelectric actuation systems to follow specified motion trajectories. The basic concept associated with this methodology lies in the specification of a target performance and the robust control scheme formulation for piezoelectric actuation systems to ensure the convergence of the position tracking error to zero. This control methodology is attractive as its implementation requires only the knowledge of the estimated system parameters …
Evaluation Of Control Techniques For Dip Transfer Gas Metal Arc Welding, Gary Dean, John Norrish, Christopher D. Cook
Evaluation Of Control Techniques For Dip Transfer Gas Metal Arc Welding, Gary Dean, John Norrish, Christopher D. Cook
Christopher Cook
Dip transfer gas metal arc welding (GMAW) is used extensively for high productivity welding of thin sheet steel, and is also useful for positional welding of thicker section steels. Unfortunately in the past, the process has gained a reputation for fusion defects, which becomes more apparent when welding traditionally difficult materials such as coated steels. This reputation can be attributed in some instances to the method of control used and the changeable nature of variables crucial to controlling heat transfer during the welding process. The paper examines the relationship between weld fusion, heat input and current for coated steel welding …