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Full-Text Articles in Science and Technology Studies
Flicker Mitigation Strategy For Dfigs During Variable Wind Conditions, Lasantha Meegahapola, Brendan Fox, Damian Flynn
Flicker Mitigation Strategy For Dfigs During Variable Wind Conditions, Lasantha Meegahapola, Brendan Fox, Damian Flynn
Dr Lasantha G Meegahapola
This paper presents a flicker mitigation scheme for the doubly-fed induction generator (DFIG) during variable wind conditions. The flicker mitigation strategy was developed based on the distribution line X/R ratio and the active power deviation from the average active power during variable wind conditions. Flicker emission was analyzed using a flicker meter based on the IEC standards. Both short-term and long-term flicker severities were analyzed during the time period of study. The flicker mitigation strategy was evaluated under different system conditions such as X/R ratio, distribution line length, shortcircuit capacity (SCC), and wind variability. It is shown that the proposed …
Voltage And Power Quality Improvement Strategy For A Dfig Wind Farm During Variable Wind Conditions, L Meegahapola, T Littler, B Fox, J Kennedy, D Flynn
Voltage And Power Quality Improvement Strategy For A Dfig Wind Farm During Variable Wind Conditions, L Meegahapola, T Littler, B Fox, J Kennedy, D Flynn
Dr Lasantha G Meegahapola
This paper presents a voltage and power quality enhancement scheme for a doubly-fed induction generator (DFIG) wind farm during variable wind conditions. The wind profiles were derived considering the measured data at a DFIG wind farm located in Northern Ireland (NI). The aggregated DFIG wind farm model was validated using measured data at a wind farm during variable generation. The voltage control strategy was developed considering the X/R ratio of the wind farm feeder which connects the wind farm and the grid. The performance of the proposed strategy was evaluated for different X/R ratios, and wind profiles with different characteristics. …
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 …
Optimization Of Frt Active Power Performance Of A Dfig During Transient Grid Faults, L Meegahapola, Damian Flynn, Tim Littler
Optimization Of Frt Active Power Performance Of A Dfig During Transient Grid Faults, L Meegahapola, Damian Flynn, Tim Littler
Dr Lasantha G Meegahapola
Optimal fault ride-through (FRT) conditions for a doubly-fed induction generator (DFIG) during a transient grid fault are analyzed with special emphasis on improving the active power generation profile. The transition states due to crowbar activation during transient faults are investigated to exploit the maximum power during the fault and post-fault period. It has been identified that operating slip, severity of fault and crowbar resistance have a direct impact on the power capability of a DFIG, and crowbar resistance can be chosen to optimize the power capability. It has been further shown that an extended crowbar period can deliver enhanced inertial …
Predicting The Fate Of Emerging Trace Organic Contaminants Of Concern During Mbr Treatment Based On Their Molecular Properties, K C. Wijekoon, L D. Nghiem, F I. Hai, J Kang, W E. Price
Predicting The Fate Of Emerging Trace Organic Contaminants Of Concern During Mbr Treatment Based On Their Molecular Properties, K C. Wijekoon, L D. Nghiem, F I. Hai, J Kang, W E. Price
William E. Price
We demonstrate that the fate of emerging trace organic contaminants during membrane bioreactor (MBR) treatment can be qualitatively predicted by assessing their molecular properties. This work futher expands the qualitative framework for the prdiction of trace organic removal by MBR treatment reported in our recent study.
The Fate Of Pharmaceuticals, Steroid Hormones, Phytoestrogens, Uv-Filters And Pesticides During Mbr Treatment, Kaushalya C. Wijekoon, Faisal I. Hai, Jinguo Kang, William E. Price, Wenshan Guo, Hao H. Ngo, Long D. Nghiem
The Fate Of Pharmaceuticals, Steroid Hormones, Phytoestrogens, Uv-Filters And Pesticides During Mbr Treatment, Kaushalya C. Wijekoon, Faisal I. Hai, Jinguo Kang, William E. Price, Wenshan Guo, Hao H. Ngo, Long D. Nghiem
William E. Price
This study examined the relationship between molecular properties and the fate of trace organic contaminants (TrOCs) in the aqueous and solid phases during wastewater treatment by MBR. A set of 29 TrOCs was selected to represent pharmaceuticals, steroid hormones, phytoestrogens, UV-filters and pesticides that occur ubiquitously in municipal wastewater. Both adsorption and biodegradation/transformation were found responsible for the removal of TrOCs by MBR treatment. A connection between biodegradation and molecular structure could be observed while adsorption was the dominant removal mechanism for the hydrophobic (logD > 3.2) compounds. Highly hydrophobic (logD > 3.2) but readily biodegradable compounds did not accumulate in sludge. …
Predicting The Fate Of Emerging Trace Organic Contaminants Of Concern During Mbr Treatment Based On Their Molecular Properties, K C. Wijekoon, L D. Nghiem, F I. Hai, J Kang, W E. Price
Predicting The Fate Of Emerging Trace Organic Contaminants Of Concern During Mbr Treatment Based On Their Molecular Properties, K C. Wijekoon, L D. Nghiem, F I. Hai, J Kang, W E. Price
Faisal I Hai
We demonstrate that the fate of emerging trace organic contaminants during membrane bioreactor (MBR) treatment can be qualitatively predicted by assessing their molecular properties. This work futher expands the qualitative framework for the prdiction of trace organic removal by MBR treatment reported in our recent study.
Trace Elements In The Si Furnace. Part I: Behavior Of Impurities In Quartz During Reduction, Elena Dal Martello, Gabriella Tranell, Oleg Ostrovski, Guangqing Zhang, Ola Raaness, Rune Burg Larsen, Kai Tang, Pramod Koshy
Trace Elements In The Si Furnace. Part I: Behavior Of Impurities In Quartz During Reduction, Elena Dal Martello, Gabriella Tranell, Oleg Ostrovski, Guangqing Zhang, Ola Raaness, Rune Burg Larsen, Kai Tang, Pramod Koshy
Faculty of Engineering and Information Sciences - Papers: Part A
Quartz and carbonaceous materials, which are used in the production of silicon as well as electrodes and refractories in the silicon furnace, contain trace elements mostly in the form of oxides. These oxides can be reduced to gaseous compounds and leave the furnace or stay in the reaction products—metal and slag. This article examines the behavior of trace elements in hydrothermal quartz and quartzite in the reaction of SiO2 with Si or SiC. Mixtures of SiO2 (quartz or quartzite), SiC, and Si in forms of lumps or pellets were heated to 1923 K and 2123 K (1650°C and 1850°C) in …
Behaviour Of New Zealand Ironsand During Iron Ore Sintering, Zhe Wang, Harold Rogers, David Pinson, Brian J. Monaghan, Sheng Chew, Paul Zulli, Sharon Nightingale, Guangqing Zhang
Behaviour Of New Zealand Ironsand During Iron Ore Sintering, Zhe Wang, Harold Rogers, David Pinson, Brian J. Monaghan, Sheng Chew, Paul Zulli, Sharon Nightingale, Guangqing Zhang
Faculty of Engineering and Information Sciences - Papers: Part A
Titanium-bearing burdens are commonly introduced into blast furnaces to protect the hearlh because the so-called "titanium bear" which is a precipitate of carbide, nitride and carbonitride of titanium may form in the blast furnace hearth if Ti02 is present in the feed [1 , 2J. New Zealand ironsand is a titanomagnetite, containing around 60 wt.% iron, 8 wt.% titanium and other substances such as silica, phosphorus and lime [3, 4]. Since it is competitive in price, introduction of the ironsand into the ferrous feed can reduce the production cost and potentially increase blast furnace campaign life. An appropriate method of …
Occurrence Of Surface Defects On Strips During Hot Rolling Process By Fem, Hai-Liang Yu, Kiet Tieu, Cheng Lu, Guan-Yu Deng, Xiang-Hua Liu
Occurrence Of Surface Defects On Strips During Hot Rolling Process By Fem, Hai-Liang Yu, Kiet Tieu, Cheng Lu, Guan-Yu Deng, Xiang-Hua Liu
Faculty of Engineering and Information Sciences - Papers: Part A
During a hot rolling process, surface defects on strips can severely affect the quality of the rolled product, particularly for two conditions: (1) there are initial defects on continuous casting slabs that propagate and/or are inherited from those on the surface of rolled steels from upstream rolling processes; and (2) there are no initial defects on continuous casting slabs, and they consequently appear on the surface of rolled steels due to improper rolling technologies. In this paper, the authors present a new 3D finite element model coupled with constrained node failure to understand better the initiation and growth of surface …
Image Guidance During Breast Radiotherapy: A Phantom Dosimetry And Radiation-Induced Second Cancer Risk Study, A Quinn, L Holloway, Peter Metcalfe
Image Guidance During Breast Radiotherapy: A Phantom Dosimetry And Radiation-Induced Second Cancer Risk Study, A Quinn, L Holloway, Peter Metcalfe
Faculty of Engineering and Information Sciences - Papers: Part A
Imaging procedures utilised for patient position verification during breast radiotherapy can add a considerable dose to organs surrounding the target volume on top of therapeutic scatter dose. This study investigated the dose from a breast kilovoltage cone-beam CT (kV-CBCT), a breast megavoltage fan-beam CT (MV-FBCT), and a TomoDirectTM breast treatment. Thermoluminescent dosimeters placed within a female anthropomorphic phantom were utilised to measure the dose to various organs and tissues. The contralateral breast, lungs and heart received 0.40 cGy, 0.45 cGy and 0.40 cGy from the kV-CBCT and 1.74 cGy, 1.39 cGy and 1.73 cGy from the MV-FBCT. In comparison to …
On The Evolution And Modelling Of Lattice Strains During The Cyclic Loading Of Twip Steel, Ahmed A. Saleh, Elena V. Pereloma, Bjorn Clausen, Donald W. Brown, Carlos N. Tome, Azdiar A. Gazder
On The Evolution And Modelling Of Lattice Strains During The Cyclic Loading Of Twip Steel, Ahmed A. Saleh, Elena V. Pereloma, Bjorn Clausen, Donald W. Brown, Carlos N. Tome, Azdiar A. Gazder
Faculty of Engineering and Information Sciences - Papers: Part A
The evolution of lattice strains in fully annealed Fe–24Mn–3Al–2Si–1Ni–0.06C twinning-induced plasticity (TWIP) steel is investigated via in situ neutron diffraction during cyclic (tension–compression) loading between strain limits of ±1%. The pronounced Bauschinger effect observed upon load reversal is accounted for by a combination of the intergranular residual stresses and the intragranular sources of back stress, such as dislocation pile-ups at the intersection of stacking faults. The recently modified elasto-plastic self-consistent (EPSC) model which empirically accounts for both intergranular and intragranular back stresses has been successfully used to simulate the macroscopic stress–strain response and the evolution of the lattice strains. The …
Transition Of Ductile And Brittle Fracture During Dwtt By Fem, Youyou Wu, Hailiang Yu, Cheng Lu, A Kiet Tieu, Ajit Godbole, Guillaume Michal
Transition Of Ductile And Brittle Fracture During Dwtt By Fem, Youyou Wu, Hailiang Yu, Cheng Lu, A Kiet Tieu, Ajit Godbole, Guillaume Michal
Faculty of Engineering and Information Sciences - Papers: Part A
Globally, steel pipelines are widely used to transport energy in the form of liquid petroleum and natural gas. The steel used in the manufacture of these pipelines must have high strength and toughness, and high resistance to fracture. The Drop Weight Tear Test (DWTT) is the most widely used test to assess brittle fracture characteristics in steel. The zones of ductile and brittle fracture during DWTT characterize the quality of pipeline steels. In this paper, the Gurson-Tvergaard-Needleman (GTN) fracture models are coupled in a Finite Element model. The ductile and brittle fracture zones in the samples are analyzed under different …
Modeling Of Thin Strip Profile During Cold Rolling On Roll Crossing And Shifting Mill, A Aljabri, Z Y. Jiang, D B. Wei, X D. Wang, H Tibar
Modeling Of Thin Strip Profile During Cold Rolling On Roll Crossing And Shifting Mill, A Aljabri, Z Y. Jiang, D B. Wei, X D. Wang, H Tibar
Faculty of Engineering and Information Sciences - Papers: Part A
Strip profile control in cold rolling of thin strip is a difficult and challenge problem found in industry. Currently using the novel type of strip rolling mill, such as the work roll crossing and shifting is the one of the main methods to control the strip profile quality in cold rolling. In this paper, 3-D finite element simulation models of the thin strip profile in cold rolling for the work roll crossing and shifting system were successfully developed. The strip profile and edge drop are discussed considering both crossing angle and shifting value of the work rolls. The research shows …
Characterisation Of Metal Deposition During Additive Manufacturing Of Ti-6al-4v By Arc-Wire Methods, Nicholas Hoye, E C. Appel, Dominic Cuiuri, Hejie Li
Characterisation Of Metal Deposition During Additive Manufacturing Of Ti-6al-4v By Arc-Wire Methods, Nicholas Hoye, E C. Appel, Dominic Cuiuri, Hejie Li
Faculty of Engineering and Information Sciences - Papers: Part A
This study considers the use of the gas tungsten arc (GTA) welding process in conjunction with 'cold' wire addition to give layer-wise build-up of thin walled structures, simulating those commonly found in aerospace applications, which may in the future be manufactured by additive means. Taguchi DOE and multiple regression analysis methods have been applied to quantitatively establish relationships between common process parameters including arc length, arc current, travel speed and wire feed speed and resulting weld bead geometries and actual metal deposition rates. Mathematical expressions for build-up height, thickness and surface roughness are presented and evaluated against experimental data, with …
Multi-Factor Coupling System Characteristic Of The Dynamic Roll Gap In The High-Speed Rolling Mill During The Unsteady Lubrication Process, Qiaoyi Wang, Zhengyi Jiang, Jingwei Zhao, Min Fang
Multi-Factor Coupling System Characteristic Of The Dynamic Roll Gap In The High-Speed Rolling Mill During The Unsteady Lubrication Process, Qiaoyi Wang, Zhengyi Jiang, Jingwei Zhao, Min Fang
Faculty of Engineering and Information Sciences - Papers: Part A
In the present work, a multi-factor coupling dynamic model of a rolling mill system for a dynamic roll gap during an unsteady lubrication process was developed on the basis of the rolling theory, lubrication and the friction theory, and the mechanical vibration theory. The multi-factor coupling model of interfacial film binding was coupled with the rolling force model, dynamic roll gap interface friction model and work roll movement model. The corresponding distributions of friction and pressure at varying surface roughness and times were systematically analyzed during the unsteady mixed lubrication process. The effects of the main processing parameters on the …
Microstructure And Texture Evolution In A Twinning-Induced-Plasticity Steel During Uniaxial Tension, Ahmed A. Saleh, Elena V. Pereloma, Azdiar A. Gazder
Microstructure And Texture Evolution In A Twinning-Induced-Plasticity Steel During Uniaxial Tension, Ahmed A. Saleh, Elena V. Pereloma, Azdiar A. Gazder
Faculty of Engineering and Information Sciences - Papers: Part A
A combination of electron back-scattering diffraction and X-ray diffraction was used to track the evolution of the microstructure and texture of a fully recrystallized Fe-24 Mn-3 Al-2 Si-1 Ni-0.06 C twinning-induced-plasticity steel during interrupted uniaxial tensile testing. Texture measurements returned the characteristic double fibre texture for face-centred cubic materials, with a relatively stronger 〈1 1 1〉 and a weaker 〈1 0 0〉 partial fibre parallel to the tensile axis. The interaction with the stable 〈1 1 1〉 oriented grains results in preferential plastic flow in the unstable 〈1 1 0〉 oriented grains. Consequently, the grains oriented along the 〈1 1 …
The Fate Of Pharmaceuticals, Steroid Hormones, Phytoestrogens, Uv-Filters And Pesticides During Mbr Treatment, Kaushalya C. Wijekoon, Faisal I. Hai, Jinguo Kang, William E. Price, Wenshan Guo, Hao H. Ngo, Long D. Nghiem
The Fate Of Pharmaceuticals, Steroid Hormones, Phytoestrogens, Uv-Filters And Pesticides During Mbr Treatment, Kaushalya C. Wijekoon, Faisal I. Hai, Jinguo Kang, William E. Price, Wenshan Guo, Hao H. Ngo, Long D. Nghiem
Faculty of Engineering and Information Sciences - Papers: Part A
This study examined the relationship between molecular properties and the fate of trace organic contaminants (TrOCs) in the aqueous and solid phases during wastewater treatment by MBR. A set of 29 TrOCs was selected to represent pharmaceuticals, steroid hormones, phytoestrogens, UV-filters and pesticides that occur ubiquitously in municipal wastewater. Both adsorption and biodegradation/transformation were found responsible for the removal of TrOCs by MBR treatment. A connection between biodegradation and molecular structure could be observed while adsorption was the dominant removal mechanism for the hydrophobic (logD > 3.2) compounds. Highly hydrophobic (logD > 3.2) but readily biodegradable compounds did not accumulate in sludge. …