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Articles 31 - 60 of 99

Full-Text Articles in Social and Behavioral Sciences

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 Jan 2017

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. For the two photon energies …


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 Jan 2017

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 …


Experimental Studies With Two Novel Silicon Detectors For The Development Of Time-Of-Flight Spectrometry Of Laser-Accelerated Proton Beams, M Würl, S Reinhardt, Anatoly B. Rosenfeld, Marco Petasecca, Michael L. F Lerch, Linh T. Tran, S Karsch, W Assmann, J Schreiber, Katia Parodi Jan 2017

Experimental Studies With Two Novel Silicon Detectors For The Development Of Time-Of-Flight Spectrometry Of Laser-Accelerated Proton Beams, M Würl, S Reinhardt, Anatoly B. Rosenfeld, Marco Petasecca, Michael L. F Lerch, Linh T. Tran, S Karsch, W Assmann, J Schreiber, Katia Parodi

Faculty of Engineering and Information Sciences - Papers: Part A

Laser-accelerated proton beams exhibit remarkably different beam characteristics as compared to conventionally accelerated ion beams. About 105 to 107 particles per MeV and msr are accelerated quasi-instantaneously within about 1 ps. The resulting energy spectrum typically shows an exponentially decaying distribution. Our planned approach to determine the energy spectrum of the particles generated in each pulse is to exploit the time-of-flight (TOF) difference of protons with different kinetic energies at 1 m distance from the laser-target interaction. This requires fast and sensitive detectors. We therefore tested two prototype silicon detectors, developed at the Centre for Medical Radiation Physics …


Statistical Properties Of Atmospheric Greenhouse Gas Measurements: Looking Down From Space And Looking Up From The Ground, Bohai Zhang, Noel A. Cressie, Debra Wunch Jan 2017

Statistical Properties Of Atmospheric Greenhouse Gas Measurements: Looking Down From Space And Looking Up From The Ground, Bohai Zhang, Noel A. Cressie, Debra Wunch

Faculty of Engineering and Information Sciences - Papers: Part A

Satellite remote sensing platforms can collect measurements on a global scale within a few days, which provides an unprecedented opportunity to characterize and understand the spatio-temporal variability of environmental variables. Because of the additional challenges of making precise and accurate measurements from space, it is essential to validate satellite remote sensing datasets with highly precise and accurate ground-based measurements. The focus of this article is on two sets of measurements: Atmospheric column-averaged carbon dioxide (CO2) collected by the Orbiting Carbon Observatory-2 (OCO-2) mission in its target mode of operation; and ground-based data used for validation from the Total Carbon Column …


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

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 that …


Direct Parametric Reconstruction With Joint Motion Estimation/Correction For Dynamic Brain Pet Data, Jieqing Jiao, Alexandre B. Bousse, Kris Thielemans, Ninon Burgos, Philip Weston, Jonathan M. Schott, David Atkinson, Simon R. Arridge, Brian F. Hutton, Pawel Markiewicz, Sebastien Ourselin Jan 2017

Direct Parametric Reconstruction With Joint Motion Estimation/Correction For Dynamic Brain Pet Data, Jieqing Jiao, Alexandre B. Bousse, Kris Thielemans, Ninon Burgos, Philip Weston, Jonathan M. Schott, David Atkinson, Simon R. Arridge, Brian F. Hutton, Pawel Markiewicz, Sebastien Ourselin

Faculty of Engineering and Information Sciences - Papers: Part A

Direct reconstruction of parametric images from raw photon counts has been shown to improve the quantitative analysis of dynamic positron emission tomography (PET) data. However it suffers from subject motion which is inevitable during the typical acquisition time of 1-2 hours. In this work we propose a framework to jointly estimate subject head motion and reconstruct the motion-corrected parametric images directly from raw PET data, so that the effects of distorted tissue-to-voxel mapping due to subject motion can be reduced in reconstructing the parametric images with motion-compensated attenuation correction and spatially aligned temporal PET data. The proposed approach is formulated …


Improvement Of Microstructure And Properties In Twin-Roll Casting 7075 Sheet By Lower Casting Speed And Compound Field, G Chen, Jintao Li, Z K. Yin, G M. Xu Jan 2017

Improvement Of Microstructure And Properties In Twin-Roll Casting 7075 Sheet By Lower Casting Speed And Compound Field, G Chen, Jintao Li, Z K. Yin, G M. Xu

Faculty of Engineering and Information Sciences - Papers: Part A

Well-developed dendrites and severe macro and micro segregations in 7075 sheet produced by horizontal twin-roll casting (TRC) deteriorates the hot-workability and properties of the sheet, which makes an obstacle for the successful use of this technology. In this paper, lower casting speed and a pulsed electric-magnetostatic compound field are used to refine microstructure and abate segregation in TRC 7075 sheet. The dendrite arm space decreases from 20 ¿m to 8¿13 ¿m and the micro-segregation degree of Mg, Zn and Cu decreases when casting speed decreases from 1.5 m/min to 0.75 m/min. The center macro-segregation belt disappears in the 0.75 m/min …


Real-Time In Vivo Rectal Wall Dosimetry Using Moskin Detectors During Linac Based Stereotactic Radiotherapy With Rectal Displacement, Kimberley Legge, Peter B. Greer, Daryl O'Connor, Lee Wilton, Matthew Richardson, Perry Hunter, Alex Wilfert, Jarad Martin, Anatoly B. Rosenfeld, Dean L. Cutajar Jan 2017

Real-Time In Vivo Rectal Wall Dosimetry Using Moskin Detectors During Linac Based Stereotactic Radiotherapy With Rectal Displacement, Kimberley Legge, Peter B. Greer, Daryl O'Connor, Lee Wilton, Matthew Richardson, Perry Hunter, Alex Wilfert, Jarad Martin, Anatoly B. Rosenfeld, Dean L. Cutajar

Faculty of Engineering and Information Sciences - Papers: Part A

Background: MOSFET dosimetry is a method that has been used to measure in-vivo doses during brachytherapy treatments and during linac based radiotherapy treatment. Rectal displacement devices (RDDs) allow for safe dose escalation for prostate cancer treatment. This study used dual MOSkin detectors to assess real-time in vivo rectal wall dose in patients with an RDD in place during a high dose prostate stereotactic body radiation therapy (SBRT) boost trial. Methods: The PROMETHEUS study commenced in 2014 and provides a prostate SBRT boost dose with a RDD in place. Twelve patients received two boost fractions of 9.5-10 Gy each delivered to …


Experimental And Modelling Approaches To The Determination Of Fatigue Crack Growth From A Structural Steel T-Butt Weld Toe, V. Tanulia, B. G. Prusty, G. M. Pearce, Alan K. Hellier, H. Li., M. Reid, A. M. Paradowska Jan 2017

Experimental And Modelling Approaches To The Determination Of Fatigue Crack Growth From A Structural Steel T-Butt Weld Toe, V. Tanulia, B. G. Prusty, G. M. Pearce, Alan K. Hellier, H. Li., M. Reid, A. M. Paradowska

Faculty of Engineering and Information Sciences - Papers: Part A

T-butt welded joints are found in many structural steel applications including buildings, bridges and offshore structures and are susceptible to fatigue crack initiation and propagation,which often leads ultimately to fast fracture failure. An example ofthis was the I-35W bridge in Minneapolis, which collapsed in 2007 resulting in 13 fatalities, as shown in Figure 1 [1]. The experimental work for this project was conducted using A350 grade black mild steel plate. An ultrasonic peening treatment was applied to one T-butt specimen to introduce compressive residual stress at the weld toe, in order to reduce the effective fatigue crack propagation rate. The …


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 Jan 2017

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, the …


Flexural Behaviour Of Gfrp Reinforced High Strength And Ultra High Strength Concrete Beams, Matthew Goldston, Alex M. Remennikov, M Neaz Sheikh Jan 2017

Flexural Behaviour Of Gfrp Reinforced High Strength And Ultra High Strength Concrete Beams, Matthew Goldston, Alex M. Remennikov, M Neaz Sheikh

Faculty of Engineering and Information Sciences - Papers: Part A

FRP bars are considered alternatives to steel bars for reinforcing concrete structures in harsh environments. FRP bars are non-corrosive, light weight, non-magnetic and have high longitudinal strength and low thermal and electric conductivity. This paper experimentally investigated the flexural behaviour of high strength concrete (HSC) and ultra-high strength concrete (UHSC) beams reinforced with glass fiber reinforced polymer (GFRP) bars that has not been addressed in the literature before. Beams of 2400 mm long, 100 mm wide and 150 mm high were tested under quasi-static loading (three point loading). Influence of reinforcement ratio and compressive strength of concrete (HSC and UHSC) …


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

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 …


Hybrid Model Predictive Control Of A Residential Hvac System With On-Site Thermal Energy Generation And Storage, Massimo Fiorentini, Josh Wall, Zhenjun Ma, Julio H. Braslavsky, Paul Cooper Jan 2017

Hybrid Model Predictive Control Of A Residential Hvac System With On-Site Thermal Energy Generation And Storage, Massimo Fiorentini, Josh Wall, Zhenjun Ma, Julio H. Braslavsky, Paul Cooper

Faculty of Engineering and Information Sciences - Papers: Part A

This paper describes the development, implementation and experimental investigation of a Hybrid Model Predictive Control (HMPC) strategy to control solar-assisted heating, ventilation and air-conditioning (HVAC) systems with on-site thermal energy generation and storage. A comprehensive approach to the thermal energy management of a residential building is presented to optimise the scheduling of the available thermal energy resources to meet a comfort objective. The system has a hybrid nature with both continuous variables and discrete, logic-driven operating modes. The proposed control strategy is organized in two hierarchical levels. At the high-level, an HMPC controller with a 24-h prediction horizon and a …


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

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 and …


A Decomposition Approach Via Fourier Sine Transform For Valuing American Knock-Out Options With Rebates, Nhat Tan Le, Duy-Minh Dang, Tran Vu Khanh Jan 2017

A Decomposition Approach Via Fourier Sine Transform For Valuing American Knock-Out Options With Rebates, Nhat Tan Le, Duy-Minh Dang, Tran Vu Khanh

Faculty of Engineering and Information Sciences - Papers: Part A

We present an innovative decomposition approach for computing the price and the hedging parameters of American knock-out options with a time-dependent rebate. Our approach is built upon: (i) the Fourier sine transform applied to the partial differential equation with a finite time-dependent spatial domain that governs the option price, and (ii) the decomposition technique that partitions the price of the option into that of the European counterpart and an early exercise premium. Our analytic representations can generalize a number of existing decomposition formulas for some European-style and American-style options. A complexity analysis of the method, together with numerical results, show …


Direct Immobilization Of Laccase On Titania Nanoparticles From Crude Enzyme Extracts Of P. Ostreatus Culture For Micro-Pollutant Degradation, Chao Ji, Ngoc Luong Nguyen, Jingwei Hou, Faisal I. Hai, Vicki Chen Jan 2017

Direct Immobilization Of Laccase On Titania Nanoparticles From Crude Enzyme Extracts Of P. Ostreatus Culture For Micro-Pollutant Degradation, Chao Ji, Ngoc Luong Nguyen, Jingwei Hou, Faisal I. Hai, Vicki Chen

Faculty of Engineering and Information Sciences - Papers: Part A

Enzymatic treatment can effectively degrade recalcitrant micro-pollutants in wastewater. However, its industrial application is constrained by the high cost of the purified enzyme preparations. This work introduces a novel technique to directly immobilize the in-house crude enzyme extracts (from P. ostreatus) onto the functionalized TiO2 nanoparticle surface. Comprehensive investigations were carried out to understand the interactions between complex crude enzyme extracts and the immobilization support. By simple dilution of the crude enzyme extract, the immobilization efficiency can be significantly improved. The resultant biocatalytic nanoparticles had comparable performance to the immobilized purified commercial enzymes. Finally, the micropollutant degradation capability …


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 Jan 2017

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 …


New Silicon Microdosimetry Probes For Rbe And Biological Dose Studies Using Stationary And Movable Targets In 12C Ion Therapy, Lachlan Chartier, Linh T. Tran, David Bolst, Alex Pogossov, Susanna Guatelli, Marco Petasecca, Michael L. F Lerch, Dale A. Prokopovich, Mark I. Reinhard, Vladimir Perevertaylo, Michael A. Jackson, Naruhiro Matsufuji, Anatoly B. Rosenfeld Jan 2017

New Silicon Microdosimetry Probes For Rbe And Biological Dose Studies Using Stationary And Movable Targets In 12C Ion Therapy, Lachlan Chartier, Linh T. Tran, David Bolst, Alex Pogossov, Susanna Guatelli, Marco Petasecca, Michael L. F Lerch, Dale A. Prokopovich, Mark I. Reinhard, Vladimir Perevertaylo, Michael A. Jackson, Naruhiro Matsufuji, Anatoly B. Rosenfeld

Faculty of Engineering and Information Sciences - Papers: Part A

Due to the high LET and dense ionisation tracks associated with ions, microdosimetric approaches have been used in carbon ion therapy to assess field quality and calculate radiobiological quantities for a variety of cell lines. There is however a lack of instrumentation for simple and routine use in a clinical environment, important for determination of RBE which provides accurate treatment planning and delivery in hadron therapy. In this study, a 10 μm thick silicon microdosimeter with 3D sensitive volumes has been used to investigate the effect of motion on the RBE and field quality of a typical 12C ion …


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 Jan 2017

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.


Nonlinear Analysis Of Biaxially Loaded Rectangular Concrete-Filled Stainless Steel Tubular Slender Beam-Columns, Vipulkumar I. Patel, Qing Quan Liang, Muhammad N. S Hadi Jan 2017

Nonlinear Analysis Of Biaxially Loaded Rectangular Concrete-Filled Stainless Steel Tubular Slender Beam-Columns, Vipulkumar I. Patel, Qing Quan Liang, Muhammad N. S Hadi

Faculty of Engineering and Information Sciences - Papers: Part A

Rectangular concrete-filled stainless steel tubular (CFSST) beam-columns utilized as supporting members for building frames may experience axial compression and biaxial moments. A numerical simulation considering the local buckling effects for thin-walled rectangular CFSST slender beam-columns has not been performed. This paper reports a stability modeling on the structural characteristics of rectangular CFSST slender beam-columns accounting for different strain-hardening of stainless steel under tension and compression. The influences of local buckling are considered in the simulation utilizing the existing effective width formulations. The developed numerical model simulates the strength interaction and load-deflection behavior of CFSST slender beam-columns. Comparisons of computed results …


The Australian Mri-Linac Program: Measuring Profiles And Pdd In A Horizontal Beam, Jarrad Begg, Armia George, Sarah Alnaghy, Trent Causer, T Alharthi, L Glaubes, Bosheng Dong, Gary Goozee, Gary P. Liney, Lois C. Holloway, Paul J. Keall Jan 2017

The Australian Mri-Linac Program: Measuring Profiles And Pdd In A Horizontal Beam, Jarrad Begg, Armia George, Sarah Alnaghy, Trent Causer, T Alharthi, L Glaubes, Bosheng Dong, Gary Goozee, Gary P. Liney, Lois C. Holloway, Paul J. Keall

Faculty of Engineering and Information Sciences - Papers: Part A

The Australian MRI-Linac consists of a fixed horizontal photon beam combined with a MRI. Commissioning required PDD and profiles measured in a horizontal set-up using a combination of water tank measurements and gafchromic film. To validate the methodology, measurements were performed comparing PDD and profiles measured with the gantry angle set to 0 and 90° on a conventional linac. Results showed agreement to within 2.0% for PDD measured using both film and the water tank at gantry 90° relative to PDD acquired using gantry 0°. Profiles acquired using a water tank at both gantry 0 and 90° showed agreement in …


Railway Turnout Failure Mode Analysis, H. Li, M. Carkagis, Alan K. Hellier, H. Zhu, J. Mcleod, S. Pannila Jan 2017

Railway Turnout Failure Mode Analysis, H. Li, M. Carkagis, Alan K. Hellier, H. Zhu, J. Mcleod, S. Pannila

Faculty of Engineering and Information Sciences - Papers: Part A

A section of New South Wales’ railways rail turnout was removed, since testing revealed that it had become defective and no longer fit-for-purpose (see photos). The University of Wollongong was commissioned to investigate the failure mode of the track section, and to provide a detailed report on the material composition, heat treatment, surface finish, wear and any material defects. Since the turnout is over 25 years old, there are no test certificates or other quality assurance documents available for review.


Stir Casting Process For Manufacture Of Al-Sic Composites, Shahin Soltani, R Azari Khosroshahi, R Taherzadeh Mousavian, Zhengyi Jiang, Alireza Fadavi Boostani, D Brabazon Jan 2017

Stir Casting Process For Manufacture Of Al-Sic Composites, Shahin Soltani, R Azari Khosroshahi, R Taherzadeh Mousavian, Zhengyi Jiang, Alireza Fadavi Boostani, D Brabazon

Faculty of Engineering and Information Sciences - Papers: Part A

Stir casting is an economical process for the fabrication of aluminum matrix composites. There are many parameters in this process, which affect the final microstructure and mechanical properties of the composites. In this study, micron-sized SiC particles were used as reinforcement to fabricate Al-3 wt% SiC composites at two casting temperatures (680 and 850 °C) and stirring periods (2 and 6 min). Factors of reaction at matrix/ceramic interface, porosity, ceramic incorporation, and agglomeration of the particles were evaluated by scanning electron microscope (SEM) and high-resolution transition electron microscope (HRTEM) studies. From microstructural characterizations, it is concluded that the shorter stirring …


Assessing The Vulnerability Of Pumping Stations To Trash Blockage In Coastal Mega-Cities Of Developing Nations, Robert Ighodaro Ogie, Sarah Dunn, Tomas Holderness, Etienne Turpin Jan 2017

Assessing The Vulnerability Of Pumping Stations To Trash Blockage In Coastal Mega-Cities Of Developing Nations, Robert Ighodaro Ogie, Sarah Dunn, Tomas Holderness, Etienne Turpin

Faculty of Engineering and Information Sciences - Papers: Part A

Pumping stations are important flood mitigation infrastructure used in coastal cities to remove accumulating floodwater from low-lying areas, where drainage is naturally poor due to very low slope gradient. In coastal mega-cities situated in developing nations, these pumping stations are often vulnerable to trash blockage as a result of frequent dumping of solid waste in water bodies. Given that blocked pumps are common causes of drainage infrastructure failure, the inability to identify the most vulnerable pumping stations can lead to inefficient allocation of limited resources for preventative maintenance of the drainage system. This study proposes an approach for measuring and …


Identity-Based Remote Data Integrity Checking With Perfect Data Privacy Preserving For Cloud Storage, Yong Yu, Man Ho Au, Giuseppe Ateniese, Xinyi Huang, Willy Susilo, Yuanshun Dai, Geyong Min Jan 2017

Identity-Based Remote Data Integrity Checking With Perfect Data Privacy Preserving For Cloud Storage, Yong Yu, Man Ho Au, Giuseppe Ateniese, Xinyi Huang, Willy Susilo, Yuanshun Dai, Geyong Min

Faculty of Engineering and Information Sciences - Papers: Part A

Remote data integrity checking (RDIC) enables a data storage server, say a cloud server, to prove to a verifier that it is actually storing a data owner's data honestly. To date, a number of RDIC protocols have been proposed in the literature. However, most of the constructions suffer from the issue of requiring complex key management. That is, they rely on the expensive public key infrastructure (PKI), which might hinder the deployment of RDIC in practice. In this paper, we propose a new construction of identity-based (ID-based) RDIC protocol by making use of key-homomorphic cryptographic primitive to reduce the system …


Sharing Social Network Data: Differentially Private Estimation Of Exponential Family Random-Graph Models, Vishesh Karwa, Pavel N. Krivitsky, Aleksandra B. Slavkovic Jan 2017

Sharing Social Network Data: Differentially Private Estimation Of Exponential Family Random-Graph Models, Vishesh Karwa, Pavel N. Krivitsky, Aleksandra B. Slavkovic

Faculty of Engineering and Information Sciences - Papers: Part A

Motivated by a real life problem of sharing social network data that contain sensitive personal information, we propose a novel approach to release and analyse synthetic graphs to protect privacy of individual relationships captured by the social network while maintaining the validity of statistical results. A case-study using a version of the Enron e-mail corpus data set demonstrates the application and usefulness of the proposed techniques in solving the challenging problem of maintaining privacy and supporting open access to network data to ensure reproducibility of existing studies and discovering new scientific insights that can be obtained by analysing such data. …


Anonymous Announcement System (Aas) For Electric Vehicle In Vanets, Man Ho Au, Joseph K. Liu, Zhenfei Zhang, Willy Susilo, Jin Li, Jianying Zhou Jan 2017

Anonymous Announcement System (Aas) For Electric Vehicle In Vanets, Man Ho Au, Joseph K. Liu, Zhenfei Zhang, Willy Susilo, Jin Li, Jianying Zhou

Faculty of Engineering and Information Sciences - Papers: Part A

Vehicular Ad Hoc Network (VANET) allows vehicles to exchange information about road and traffic conditions through wireless communications. Nevertheless, providing reliable and authenticated information without violating the user's privacy seems contradictory. In this paper, we propose an Anonymous Announcement System especially designed for Electric Vehicle (EV) in VANETs to achieve the aforementioned contradictory goals. We demonstrated the feasibility of the protocol with a prototype implementation on a suitable device and a network simulation with our protocol added on top of a normal VANET.


Development Of A Dynamic Model For A Hybrid Photovoltaic Thermal Collector - Solar Air Heater With Fins, Wenke Fan, Georgios Kokogiannakis, Zhenjun Ma, Paul Cooper Jan 2017

Development Of A Dynamic Model For A Hybrid Photovoltaic Thermal Collector - Solar Air Heater With Fins, Wenke Fan, Georgios Kokogiannakis, Zhenjun Ma, Paul Cooper

Faculty of Engineering and Information Sciences - Papers: Part A

A dynamic model for a hybrid Photovoltaic Thermal Collector-Solar Air Heater (PVT-SAH) with longitudinal fins was developed to enable assessment of the potential of the system to provide high temperature outlet air (60-90 °C) under dynamic boundary conditions. The model description includes the method for discretising the system into a number of control volumes, the energy balance equations for each control volume and the implementation of the numerical solution. Model validation has been successfully undertaken by using empirical verification of model predictions with an experimental facility and by comparing the model outputs with the reference data from the literature. The …


Using Contrastive Divergence To Seed Monte Carlo Mle For Exponential-Family Random Graph Models, Pavel N. Krivitsky Jan 2017

Using Contrastive Divergence To Seed Monte Carlo Mle For Exponential-Family Random Graph Models, Pavel N. Krivitsky

Faculty of Engineering and Information Sciences - Papers: Part A

Exponential-family models for dependent data have applications in a wide variety of areas, but the dependence often results in an intractable likelihood, requiring either analytic approximation or MCMC-based techniques to fit, the latter requiring an initial parameter configuration to seed their simulations. A poor initial configuration can lead to slow convergence or outright failure. The approximate techniques that could be used to find them tend not to be as general as the simulation-based and require implementation separate from that of the MLE-finding algorithm. Contrastive divergence is a more recent simulation-based approximation technique that uses a series of abridged MCMC runs …


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 Jan 2017

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 …