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6162 full-text articles. Page 4 of 223.

Low Voltage Ride-Through Enhancement Of Dfig-Based Wind Turbine Using Dc Link Switchable Resistive Type Fault Current Limiter, Seyed Behzad Naderi, Michael Negnevitsky, Amin Jalilian, Mehrdad Tarafdar Hagh, Kashem M. Muttaqi 2017 University of Tasmania

Low Voltage Ride-Through Enhancement Of Dfig-Based Wind Turbine Using Dc Link Switchable Resistive Type Fault Current Limiter, Seyed Behzad Naderi, Michael Negnevitsky, Amin Jalilian, Mehrdad Tarafdar Hagh, Kashem M. Muttaqi

Faculty of Engineering and Information Sciences - Papers: Part A

Doubly-fed induction generator (DFIG)-based wind turbines utilise small-scale voltage sourced converters with a limited overcurrent withstand capability, which makes the DFIG-based wind turbines very vulnerable to grid faults. Often, modern DFIG systems employ a crowbar protection at the rotor circuit to protect the rotor side converter (RSC) during grid faults. This method converts the DFIG to a squirrel cage induction generator, which does not comply with the new grid codes. The recent grid codes need wind turbines to stay connected to the utility grid during and after power system faults, especially in high penetration level of wind power. Furthermore ...


Application Of Fractional Calculus In Modelling Ballast Deformation Under Cyclic Loading, Yifei Sun, Buddhima Indraratna, John Philip Carter, Timothy R. Marchant, Sanjay Nimbalkar 2017 University of Wollongong

Application Of Fractional Calculus In Modelling Ballast Deformation Under Cyclic Loading, Yifei Sun, Buddhima Indraratna, John Philip Carter, Timothy R. Marchant, Sanjay Nimbalkar

Faculty of Engineering and Information Sciences - Papers: Part A

Most constitutive models can only simulate cumulative deformation after a limited number of cycles. However, railroad ballast usually experiences a large number of train passages that cause history-dependent long-term deformation. Fractional calculus is an efficient tool for modelling this phenomenon and therefore is incorporated into a constitutive model for predicting the cumulative deformation. The proposed model is further validated by comparing the model predictions with a series of corresponding experimental results. It is observed that the proposed model can realistically simulate the cumulative deformation of ballast from the onset of loading up to a large number of load cycles.


Holistic Sludge Management Through Ozonation: A Critical Review, Galilee U. Semblante, Faisal I. Hai, Dionysios D. Dionysiou, Kensuke Fukushi, William E. Price, Long D. Nghiem 2017 University of Wollongong

Holistic Sludge Management Through Ozonation: A Critical Review, Galilee U. Semblante, Faisal I. Hai, Dionysios D. Dionysiou, Kensuke Fukushi, William E. Price, Long D. Nghiem

Faculty of Engineering and Information Sciences - Papers: Part A

This paper critically reviews the multidimensional benefits of ozonation in wastewater treatment plants. These benefits include sludge reduction, removal of emerging trace organic contaminants (TrOC) from wastewater and sludge, and resource recovery from sludge. Literature shows that ozonation leads to sludge solubilisation, reducing overall biomass yield. Sludge solubilisation is primarily influenced by ozone dosage, which, in turn, depends on the fraction of ozonated sludge, ozone concentration, and sludge concentration. Additionally, sludge ozonation facilitates the removal of TrOCs from wastewater. On the other hand, by inducing cell lysis, ozonation increases the chemical oxygen demand (COD) and nutrient concentration of the sludge ...


Factors Governing Mass Transfer During Membrane Electrodialysis Regeneration Of Licl Solution For Liquid Desiccant Dehumidification Systems, Ali Hussein Al-Jubainawi, Zhenjun Ma, Yi Guo, Long D. Nghiem, Paul Cooper, Weihua Li 2017 University of Wollongong

Factors Governing Mass Transfer During Membrane Electrodialysis Regeneration Of Licl Solution For Liquid Desiccant Dehumidification Systems, Ali Hussein Al-Jubainawi, Zhenjun Ma, Yi Guo, Long D. Nghiem, Paul Cooper, Weihua Li

Faculty of Engineering and Information Sciences - Papers: Part A

This study investigates the mass transfer mechanisms and the performance of membrane electrodialysis (ED) for regenerating lithium chloride (LiCl) solution commonly used in liquid desiccant dehumidification systems. Experiments were conducted using an ED experimental system while numerical simulation was performed using COMSOL Multiphysics. The results showed that the water flux transfer due to osmosis and electro-osmosis during ED regeneration of LiCl liquid desiccant was significant and could not be ignored. The water flux due to osmosis and electro-osmosis is directly associated with the osmotic gradient and the applied current between the cathode and anode, respectively. The average flux of water ...


Micromechanics-Based Investigation Of Fouled Ballast Using Large-Scale Triaxial Tests And Discrete Element Modeling, Ngoc Trung Ngo, Buddhima Indraratna, Cholachat Rujikiatkamjorn 2017 University of Wollongong

Micromechanics-Based Investigation Of Fouled Ballast Using Large-Scale Triaxial Tests And Discrete Element Modeling, Ngoc Trung Ngo, Buddhima Indraratna, Cholachat Rujikiatkamjorn

Faculty of Engineering and Information Sciences - Papers: Part A

Railway ballast comprises unbounded discrete grains that are often used to form a load-bearing platform for tracks. Ballast degradation as trains pass over the tracks and infiltration of external fines including slurried (pumped) fine subgrade soils are two of the main reasons for ballast fouling. Fouling causes tracks to settle and also reduces the load-bearing capacity, which is associated with a reduction in internal friction and increased lateral spreading of the ballast layer. This paper presents a study of mobilized friction angle, volumetric behavior, and associated evolutions of contact and fabric anisotropy of fouled ballast subjected to monotonic triaxial loading ...


Thin-Film Composite Forward Osmosis Membranes Functionalized With Graphene Oxide-Silver Nanocomposites For Biofouling Control, Andreia Faria, Caihong Liu, Ming Xie, Francois Perreault, Long D. Nghiem, Jun Ma, Menachem Elimelech 2017 Yale University

Thin-Film Composite Forward Osmosis Membranes Functionalized With Graphene Oxide-Silver Nanocomposites For Biofouling Control, Andreia Faria, Caihong Liu, Ming Xie, Francois Perreault, Long D. Nghiem, Jun Ma, Menachem Elimelech

Faculty of Engineering and Information Sciences - Papers: Part A

Innovative approaches to prevent bacterial attachment and biofilm growth on membranes are critically needed to avoid decreasing membrane performance due to biofouling. In this study, we propose the fabrication of anti-biofouling thin-film composite membranes functionalized with graphene oxide-silver nanocomposites. In our membrane modification strategy, carboxyl groups on the graphene oxide-silver nanosheets are covalently bonded to carboxyl groups on the surface of thin-film composite membranes via a crosslinking reaction. Further characterization, such as scanning electron microscopy and Raman spectroscopy, revealed the immobilization of graphene oxide-silver nanocomposites on the membrane surface. Graphene oxide-silver modified membranes exhibited an 80% inactivation rate against attached ...


Development Of Microencapsulated Phase Change Material For Solar Thermal Energy Storage, Weiguang Su, Jo Darkwa, Georgios Kokogiannakis 2017 University of Nottingham, Qilu University of Technology

Development Of Microencapsulated Phase Change Material For Solar Thermal Energy Storage, Weiguang Su, Jo Darkwa, Georgios Kokogiannakis

Faculty of Engineering and Information Sciences - Papers: Part A

In this paper a novel microencapsulated phase change material (MF-3) has been developed and tested for solar assisted hot water storage systems. Even though the morphology of the sample was affected by the type of emulsifier used for fabrication it recorded the highest energy storage capacity of 126 kJ/kg with encapsulation efficiency of 97.4% as compared with other developed samples. For the purpose of assessing its thermal effectiveness it was theoretically evaluated in a compacted fixed bed TES unit and found to be capable of achieving a higher energy storage density as well as relatively smaller physical storage ...


Displaced Hardness Peak Phenomenon In Heat-Affected Zone Of Welded Quenched And Tempered Em812 Steel, Druce P. Dunne, W Pang 2017 University of Wollongong

Displaced Hardness Peak Phenomenon In Heat-Affected Zone Of Welded Quenched And Tempered Em812 Steel, Druce P. Dunne, W Pang

Faculty of Engineering and Information Sciences - Papers: Part A

Investigations of microstructural and hardness gradients in the heat-affected zone (HAZ) of quenched and tempered (Q&T) steels have indicated that peak hardness does not occur in the grain-coarsened heat-affected zone (GCHAZ) adjacent to the fusion boundary, which is typical of ferritic steels, but corresponds more closely to the grain-refined region (GRHAZ). This phenomenon, the displaced hardness peak (DHP) effect, is considered to arise when the hardenability of the steel is high enough to result in the same microstructure in the GC and GR heat-affected zones, except for significant refinement of the microstructure of the GRHAZ, which increases the hardness ...


A Torsional Mre Joint For A C-Shaped Robotic Leg, M D. Christie, Shuaishuai Sun, Donghong Ning, Haiping Du, Shiwu Zhang, Weihua Li 2017 University of Wollongong

A Torsional Mre Joint For A C-Shaped Robotic Leg, M D. Christie, Shuaishuai Sun, Donghong Ning, Haiping Du, Shiwu Zhang, Weihua Li

Faculty of Engineering and Information Sciences - Papers: Part A

Serving to improve stability and energy efficiency during locomotion, in nature, animals modulate their leg stiffness to adapt to their terrain. Now incorporated into many locomotive robot designs, such compliance control can enable disturbance rejection and improved transition between changing ground conditions. This paper presents a novel design of a variable stiffness leg utilizing a magnetorheological elastomer joint in a literal rolling spring loaded inverted pendulum (R-SLIP) morphology. Through the semi-active control of this hybrid permanent-magnet and coil design, variable stiffness is realized, offering a design which is capable of both softening and stiffening in an adaptive sort of way ...


Pricing Credit Default Swaps Under A Multi-Scale Stochastic Volatility Model, Wenting Chen, Xin-Jiang He 2017 Jiangnan University

Pricing Credit Default Swaps Under A Multi-Scale Stochastic Volatility Model, Wenting Chen, Xin-Jiang He

Faculty of Engineering and Information Sciences - Papers: Part A

In this paper, we consider the pricing of credit default swaps (CDSs) with the reference asset driven by a geometric Brownian motion with a multi-scale stochastic volatility (SV), which is a two-factor volatility process with one factor controlling the fast time scale and the other representing the slow time scale. A key feature of the current methodology is to establish an equivalence relationship between the CDS and the down-and-out binary option through the discussion of "no default" probability, while balancing the two SV processes with the perturbation method. An approximate but closed-form pricing formula for the CDS contract is finally ...


Optimum Resistive Type Fault Current Limiter: An Efficient Solution To Achieve Maximum Fault Ride-Through Capability Of Fixed-Speed Wind Turbines During Symmetrical And Asymmetrical Grid Faults, Seyed Behzad Naderi, Michael Negnevitsky, Amin Jalilian, Mehrdad Tarafdar Hagh, Kashem M. Muttaqi 2017 University of Tasmania (UTAS)

Optimum Resistive Type Fault Current Limiter: An Efficient Solution To Achieve Maximum Fault Ride-Through Capability Of Fixed-Speed Wind Turbines During Symmetrical And Asymmetrical Grid Faults, Seyed Behzad Naderi, Michael Negnevitsky, Amin Jalilian, Mehrdad Tarafdar Hagh, Kashem M. Muttaqi

Faculty of Engineering and Information Sciences - Papers: Part A

This paper proposes an optimum resistive type fault current limiter (OR-FCL) as an efficient solution to achieve maximum fault ride-through (FRT) capability of fixed-speed wind turbines (FSWT) during various grid faults. In this paper, a dedicated control circuit is designed for the OR-FCL that enables it to insert an optimum value of resistance in the FSWT's fault current's path for improving transient behavior of the FSWT. The optimum resistance value depends on fault location and prefault active power. The control circuit of the proposed OR-FCL is capable of calculating the optimum resistance value for all the prefault conditions ...


Multivariate Spatial Data Fusion For Very Large Remote Sensing Datasets, Hai Nguyen, Noel A. Cressie, Amy Braverman 2017 Caltech

Multivariate Spatial Data Fusion For Very Large Remote Sensing Datasets, Hai Nguyen, Noel A. Cressie, Amy Braverman

Faculty of Engineering and Information Sciences - Papers: Part A

Global maps of total-column carbon dioxide (CO2) mole fraction (in units of parts per million) are important tools for climate research since they provide insights into the spatial distribution of carbon intake and emissions as well as their seasonal and annual evolutions. Currently, two main remote sensing instruments for total-column CO2 are the Orbiting Carbon Observatory-2 (OCO-2) and the Greenhouse gases Observing SATellite (GOSAT), both of which produce estimates of CO2 concentration, called profiles, at 20 different pressure levels. Operationally, each profile estimate is then convolved into a single estimate of column-averaged CO2 using a linear pressure weighting function. This ...


A Robust And Tuneable Mid-Infrared Optical Switch Enabled By Bulk Dirac Fermions, Chunhui Zhu, Fengqiu Wang, Yafei Meng, Xiang Yuan, Faxian Xiu, Hongyu Luo, Yazhou Wang, Jianfeng Li, Xinjie Lv, Liang He, Yongbing Xu, Junfeng Liu, C Zhang, Yi Shi, Rong Zhang, Shining Zhu 2017 Nanjing University

A Robust And Tuneable Mid-Infrared Optical Switch Enabled By Bulk Dirac Fermions, Chunhui Zhu, Fengqiu Wang, Yafei Meng, Xiang Yuan, Faxian Xiu, Hongyu Luo, Yazhou Wang, Jianfeng Li, Xinjie Lv, Liang He, Yongbing Xu, Junfeng Liu, C Zhang, Yi Shi, Rong Zhang, Shining Zhu

Faculty of Engineering and Information Sciences - Papers: Part A

Pulsed lasers operating in the mid-infrared (3–20 μm) are important for a wide range of applications in sensing, spectroscopy, imaging and communications. Despite recent advances with mid-infrared gain platforms, the lack of a capable pulse generation mechanism remains a significant technological challenge. Here we show that bulk Dirac fermions in molecular beam epitaxy grown crystalline Cd3As2, a three-dimensional topological Dirac semimetal, constitutes an exceptional ultrafast optical switching mechanism for the mid-infrared. Significantly, we show robust and effective tuning of the scattering channels of Dirac fermions via an element doping approach, where photocarrier relaxation times are found ...


History Of International Workshop On Mini-Micro- And Nano- Dosimetry (Mmnd) And Innovation Technologies In Radiation Oncology (Itro), Anatoly B. Rosenfeld, Marco Zaider, J Yamada, M Zelefsky 2017 University of Wollongong

History Of International Workshop On Mini-Micro- And Nano- Dosimetry (Mmnd) And Innovation Technologies In Radiation Oncology (Itro), Anatoly B. Rosenfeld, Marco Zaider, J Yamada, M Zelefsky

Faculty of Engineering and Information Sciences - Papers: Part A

The biannual MMND (former MMD) - IPCT workshops was founded in collaboration between the Centre for Medical Radiation Physics, University of Wollongong and the Memorial Sloan Kettering Cancer Center (MSKCC) in 2001 and has become an important international multidisciplinary forum for the discussion of advanced quality assurance (QA) dosimetry technology for radiation therapy and space science, as well as advanced technologies for clinical cancer treatment.


New 3d Silicon Detectors For Dosimetry In Microbeam Radiation Therapy, Michael L. F Lerch, Andrew Dipuglia, Matthew Cameron, Pauline Fournier, Jeremy A. Davis, Marco Petasecca, Iwan Cornelius, Vladimir Perevertaylo, Anatoly B. Rosenfeld 2017 University of Wollongong

New 3d Silicon Detectors For Dosimetry In Microbeam Radiation Therapy, Michael L. F Lerch, Andrew Dipuglia, Matthew Cameron, Pauline Fournier, Jeremy A. Davis, Marco Petasecca, Iwan Cornelius, Vladimir Perevertaylo, Anatoly B. Rosenfeld

Faculty of Engineering and Information Sciences - Papers: Part A

Microbeam Radiation Therapy (MRT) involves the use of a spatially fractionated beam of synchrotron generated X-rays to treat tumours. MRT treatment is delivered via an array of high dose 'peaks' separated by low dose 'valleys'. A good Peak to Valley Dose Ratio (PVDR) is an important indicator of successful treatment outcomes. MRT dosimetry requires a radiation hard detector with high spatial resolution, large dynamic range, which is ideally real-time and tissue equivalent. We have developed a Silicon Strip Detector (SSD) and very recently, a new 3D MESA SSD to meet the very stringent requirements of MRT dosimetry. We have compared ...


Optimisation Of Output Factor Measurements Using The Magic Plate 512 Silicon Dosimeter Array In Small Megavoltage Photon Fields, Kananan Utitsarn, Z A. Alrowaili, Nauljun Stansook, Michael L. F Lerch, Marco Petasecca, Martin G. Carolan, Anatoly B. Rosenfeld 2017 University of Wollongong

Optimisation Of Output Factor Measurements Using The Magic Plate 512 Silicon Dosimeter Array In Small Megavoltage Photon Fields, Kananan Utitsarn, Z A. Alrowaili, Nauljun Stansook, Michael L. F Lerch, Marco Petasecca, Martin G. Carolan, Anatoly B. Rosenfeld

Faculty of Engineering and Information Sciences - Papers: Part A

We evaluate the impact of an air gap and optimization of this air gap for the MP512 silicon detector array when operated in dosimetry mode for small photon field measurements in solid water. We present output factor measurements for 6MV and 10 MV photon beams with the square field sizes ranging from 0.5 to 10 cm2. The size of the air gap above the MP512 detector was changed from 0.5, 1.0, 1.2, 2.0 and 2.6 mm. We compare the output factors measurements of the MP512 with EBT3 film and the MOSkin dosimeter ...


Monte Carlo Characterisation Of The Dose Magnifying Glass For Proton Therapy Quality Assurance, Aaron Merchant, Susanna Guatelli, Marco Petasecca, Michael A. Jackson, Anatoly B. Rosenfeld 2017 University of Wollongong

Monte Carlo Characterisation Of The Dose Magnifying Glass For Proton Therapy Quality Assurance, Aaron Merchant, Susanna Guatelli, Marco Petasecca, Michael A. Jackson, Anatoly B. Rosenfeld

Faculty of Engineering and Information Sciences - Papers: Part A

A Geant4 Monte Carlo simulation study was carried out to characterise a novel silicon strip detector, the Dose Magnifying Glass (DMG), for use in proton therapy Quality Assurance. We investigated the possibility to use DMG to determine the energy of the incident proton beam. The advantages of DMG are quick response, easy operation and high spatial resolution. In this work we theoretically proved that DMG can be used for QA in the determination of the energy of the incident proton beam, for ocular and prostate cancer therapy. The study was performed by means of Monte Carlo simulations Experimental measurements are ...


Introducing Dynamic Dosimaging: Potential Applications For Mri-Linac, Peter E. Metcalfe, Sarah Alnaghy, Matthew Newall, Maegan Gargett, Mitchell Duncan, Gary P. Liney, Jarrad Begg, Bradley M. Oborn, Marco Petasecca, Michael L. F Lerch, Anatoly B. Rosenfeld 2017 University of Wollongong

Introducing Dynamic Dosimaging: Potential Applications For Mri-Linac, Peter E. Metcalfe, Sarah Alnaghy, Matthew Newall, Maegan Gargett, Mitchell Duncan, Gary P. Liney, Jarrad Begg, Bradley M. Oborn, Marco Petasecca, Michael L. F Lerch, Anatoly B. Rosenfeld

Faculty of Engineering and Information Sciences - Papers: Part A

The new era of intra-fraction dose tracking in radiation therapy delivery demands new dosimetry methods, whereby a moving frame of reference as a function of time may be required. This introduces a new paradigm into radiation therapy dose verification. The term we propose to describe this is dynamic dosimaging, which by our definition is tracking the location of a dosimeter array in real time during on-line radiation dose acquisition.


Selection Bias In The Reported Performances Of Ad Classification Pipelines, Alex F. Mendelson, Maria A. Zuluaga, Marco Lorenzi, Brian F. Hutton, Sebastien Ourselin 2017 University College London

Selection Bias In The Reported Performances Of Ad Classification Pipelines, Alex F. Mendelson, Maria A. Zuluaga, Marco Lorenzi, Brian F. Hutton, Sebastien Ourselin

Faculty of Engineering and Information Sciences - Papers: Part A

The last decade has seen a great proliferation of supervised learning pipelines for individual diagnosis and prognosis in Alzheimer's disease. As more pipelines are developed and evaluated in the search for greater performance, only those results that are relatively impressive will be selected for publication. We present an empirical study to evaluate the potential for optimistic bias in classification performance results as a result of this selection. This is achieved using a novel, resampling-based experiment design that effectively simulates the optimisation of pipeline specifications by individuals or collectives of researchers using cross validation with limited data. Our findings indicate ...


Model-Based Optimization Of Ground Source Heat Pump Systems, Zhenjun Ma, Lei Xia 2017 University of Wollongong

Model-Based Optimization Of Ground Source Heat Pump Systems, Zhenjun Ma, Lei Xia

Faculty of Engineering and Information Sciences - Papers: Part A

This paper presents the development of an optimization strategy for ground source heat pump (GSHP) systems equipped with variable speed pumps in the ground loop system. The optimization problem is formulated using a model-based approach, in which the component models are used to estimate the system performance under various trial settings and an exhaustive search method is used to identify the optimal settings under the search ranges defined. The variable optimized is the outlet water temperature from the ground heat exchangers, which can be used as a set-point to control the operation of the variable speed pumps in the ground ...


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