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Full-Text Articles in Social and Behavioral Sciences

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

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.


Experimental Investigation And Simplified Modeling Of Response Of Steel Plates Subjected To Close-In Blast Loading From Spherical Liquid Explosive Charges, Alex M. Remennikov, Tuan D. Ngo, Damith Mohotti, Brian Uy, Michael Netherton Jan 2017

Experimental Investigation And Simplified Modeling Of Response Of Steel Plates Subjected To Close-In Blast Loading From Spherical Liquid Explosive Charges, Alex M. Remennikov, Tuan D. Ngo, Damith Mohotti, Brian Uy, Michael Netherton

Faculty of Engineering and Information Sciences - Papers: Part A

Detonations of nitromethane spherical charges have been carried out to study close-in blast loading of steel plates and the effectiveness of several protective solutions. Three types of bare steel plates, namely mild steel, high-strength steel, and stainless steel were subjected to explosive blast loading. Steel plates of the same type with polyurea coating and composite covers were also subjected to localized blast loading. During an explosive field trial, the blast pressures and displacements of steel plates were measured. Additionally, loading of steel plates by the impinging detonation products was captured by high-speed video recordings. This experimental program has produced results …


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 Jan 2017

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 …


Vibration-Induced Aerodynamic Loads On Large Horizontal Axis Wind Turbine Blades, Xiong Liu, Cheng Lu, Shi Liang, Ajit R. Godbole, Yan Chen Jan 2017

Vibration-Induced Aerodynamic Loads On Large Horizontal Axis Wind Turbine Blades, Xiong Liu, Cheng Lu, Shi Liang, Ajit R. Godbole, Yan Chen

Faculty of Engineering and Information Sciences - Papers: Part A

The blades of a large Horizontal Axis Wind Turbine (HAWT) are subjected to significant vibrations during operation. The vibrations affect the dynamic flow field around the blade and consequently alter the aerodynamic forces on the blade. In order to better understand the influence of blade vibrations on the aerodynamic loads, the dynamic stall characteristics of an S809 airfoil undergoing translational motion as well as pitching motion were investigated using Computational Fluid Dynamics (CFD) techniques. Simulation results indicated that both the out-of-plane and in-plane translational motions of the airfoil affect the unsteady aerodynamic forces significantly. In order to investigate the effects …


Liquid Desiccant Lithium Chloride Regeneration By Membrane Distillation For Air Conditioning, Hung Duong, Faisal I. Hai, Ali Aljubainawi, Zhenjun Ma, Tao He, Long D. Nghiem Jan 2017

Liquid Desiccant Lithium Chloride Regeneration By Membrane Distillation For Air Conditioning, Hung Duong, Faisal I. Hai, Ali Aljubainawi, Zhenjun Ma, Tao He, Long D. Nghiem

Faculty of Engineering and Information Sciences - Papers: Part A

Liquid desiccant air conditioning (LDAC) has emerged as an attractive technology for improving indoor air quality and thermal comfort. Regeneration of liquid desiccants is critical to sustain the process efficiency of LDAC. This study explores membrane distillation (MD) for regeneration of lithium chloride (LiCl) desiccant solution commonly used in LDAC. The results demonstrate the viability of MD for LiCl regeneration. The MD process at the feed temperature of 65 °C could increase the LiCl concentration up to 29 wt.% without any observable LiCl loss. Given the high concentration of the LiCl solution feed, unlike traditional desalination applications, the impact of …


Performance Evaluation Of High Strength Concrete And Steel Fibre High Strength Concrete Columns Reinforced With Gfrp Bars And Helices, Hayder Alaa Hasan, M Neaz Sheikh, Muhammad N. S Hadi Jan 2017

Performance Evaluation Of High Strength Concrete And Steel Fibre High Strength Concrete Columns Reinforced With Gfrp Bars And Helices, Hayder Alaa Hasan, M Neaz Sheikh, Muhammad N. S Hadi

Faculty of Engineering and Information Sciences - Papers: Part A

This study presents the results of an experimental investigation on high strength concrete (HSC) and steel fibre high strength concrete (SFHSC) circular column specimens reinforced longitudinally and transversely with Glass Fibre-Reinforced Polymer (GFRP) bars and helices, respectively. The Influence of the type of the reinforcement (steel and GFRP), the pitch of the transverse reinforcement, the addition of the steel fibres and the loading condition (concentric, eccentric and four-point loading) on the performance of the specimens was investigated. The study showed that the GFRP bar reinforced HSC (GFRP-HSC) specimen is as efficient as the steel bar reinforced HSC (steel-HSC) specimen in …


Development Of Microencapsulated Phase Change Material For Solar Thermal Energy Storage, Weiguang Su, Jo Darkwa, Georgios Kokogiannakis Jan 2017

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 size than …


Effects Of Fabrication Technique On Tensile Properties Of Fiber Reinforced Polymer, Thong M. Pham, Muhammad N. S Hadi, Jim Youssef Jan 2017

Effects Of Fabrication Technique On Tensile Properties Of Fiber Reinforced Polymer, Thong M. Pham, Muhammad N. S Hadi, Jim Youssef

Faculty of Engineering and Information Sciences - Papers: Part A

This study investigated the effects of fabrication technique on the tensile properties of fiber reinforced polymer (FRP) flat coupon tests. A total of 20 FRP flat coupons were prepared by two different techniques, which were tested in tension until failure. The first technique of preparing the FRP coupons was based on the recommendation of ASTM D7565/D7565M-10, named the “Cutting Technique,” while the second technique, named the “Folding Technique,” was proposed by this study. Experimental results from this study indicated that preparing FRP coupons using the Cutting Technique resulted in a reduction in the tensile properties as compared to coupons prepared …


Fractal Spectral Triples On Kellendonk's C*-Algebra Of A Substitution Tiling, Michael Mampusti, Michael F. Whittaker Jan 2017

Fractal Spectral Triples On Kellendonk's C*-Algebra Of A Substitution Tiling, Michael Mampusti, Michael F. Whittaker

Faculty of Engineering and Information Sciences - Papers: Part A

.We introduce a new class of noncommutative spectral triples on Kellendonk's C*-algebra associated with a nonperiodic substitution tiling. These spectral triples are constructed from fractal trees on tilings, which define a geodesic distance between any two tiles in the tiling. Since fractals typically have infinite Euclidean length, the geodesic distance is defined using Perron-Frobenius theory, and is self-similar with scaling factor given by the Perro-Frobenius eigenvalue. We show that each spectral triple is θ-summable, and respects the hierarchy of the substitution system. To elucidate our results, we construct a fractal tree on the Penrose tiling, and explicitly show how it …


Stabilization Of Track Substructure With Geoinclusions- Experimental Evidence And Dem Simulation, Ngoc Trung Ngo, Buddhima Indraratna, Cholachat Rujikiatkamjorn Jan 2017

Stabilization Of Track Substructure With Geoinclusions- Experimental Evidence And Dem Simulation, Ngoc Trung Ngo, Buddhima Indraratna, Cholachat Rujikiatkamjorn

Faculty of Engineering and Information Sciences - Papers: Part A

This article reviews on current knowledge of rail track geomechanics, including several important concepts and topics related to laboratory testing and computational modelling, to study the shear stress-strain and deformation of ballast improved by geosynthetics and recycled rubber mats. The effect that impact loads have on ballast degradation and its mitigation due to resilient synthetic mats (i.e. rubber mats) between the ballast and the subballast is investigated using large-scale impact-testing apparatus. Computational modelling with finite element and discrete element methods are increasingly being used to model ballasted tracks reinforced with geosynthetics to capture the continuum media of formation soils and …


Equivalence And Stable Isomorphism Of Groupoids, And Diagonal-Preserving Stable Isomorphisms Of Graph C*-Algebras And Leavitt Path Algebras, Toke Meier Carlsen, Efren Ruiz, Aidan Sims Jan 2017

Equivalence And Stable Isomorphism Of Groupoids, And Diagonal-Preserving Stable Isomorphisms Of Graph C*-Algebras And Leavitt Path Algebras, Toke Meier Carlsen, Efren Ruiz, Aidan Sims

Faculty of Engineering and Information Sciences - Papers: Part A

We prove that ample groupoids with σ-compact unit spaces are equivalent if and only if they are stably isomorphic in an appropriate sense, and relate this to Matui's notion of Kakutani equivalence. We use this result to show that diagonal-preserving stable isomorphisms of graph C*-algebras or Leavitt path algebras give rise to isomorphisms of the groupoids of the associated stabilised graphs. We deduce that the Leavitt path algebras LZ(E2) and LZ(E2-) are not stably *-isomorphic.


Full Scale Co-Digestion Of Wastewater Sludge And Food Waste: Bottlenecks And Possibilities, Long D. Nghiem, Konrad Koch, David Bolzonella, Jörg E. Drewes Jan 2017

Full Scale Co-Digestion Of Wastewater Sludge And Food Waste: Bottlenecks And Possibilities, Long D. Nghiem, Konrad Koch, David Bolzonella, Jörg E. Drewes

Faculty of Engineering and Information Sciences - Papers: Part A

Wastewater treatment plants in many countries use anaerobic digesters for biosolids management and biogas generation. Opportunities exist to utilise the spare capacity of these digesters to co-digest food waste and sludge for energy recovery and a range of other economic and environmental benefits. This paper provides a critical perspective for full-scale implementation of co-digestion of food waste and wastewater sludge. Data compiled from full-scale facilities and the peer-reviewed literature revealed several key bottlenecks hindering full-scale implementation of co-digestion. Indeed, co-digestion applications remain concentrated mostly in countries or regions with favourable energy and waste management policies. Not all environmental benefits from …


Innovative Analysis Of Luders Band Behaviour In X80 Pipeline Steel, Jian Han, Cheng Lu, Bintao Wu, Jintao Li, Hui Jun Li, Yao Lu, Qiuzhi Gao Jan 2017

Innovative Analysis Of Luders Band Behaviour In X80 Pipeline Steel, Jian Han, Cheng Lu, Bintao Wu, Jintao Li, Hui Jun Li, Yao Lu, Qiuzhi Gao

Faculty of Engineering and Information Sciences - Papers: Part A

In this study, the influence of Luders bands, which are frequently observed after the pipe coating process, is investigated. Stratified tensile test specimens, machined from different locations across the thickness of an X80 line pipe, were tested. The Luders bands were observed by using a digital image correlation (DIC) in the specimen machined from halfway across the pipe wall thickness. The specimens from the selected locations related to the Luders bands were studied and compared by means of optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD), electron backscatter diffraction (EBSD) and standard mechanical testing. The results display that …


Characterization And Mechanical Properties Of Α-Al2o3 Particle Reinforced Aluminium Matrix Composites, Synthesized Via Uniball Magneto-Milling And Uniaxial Hot Pressing, Buraq Talib Shalash Al-Mosawi, David Wexler, Andrzej Calka Jan 2017

Characterization And Mechanical Properties Of Α-Al2o3 Particle Reinforced Aluminium Matrix Composites, Synthesized Via Uniball Magneto-Milling And Uniaxial Hot Pressing, Buraq Talib Shalash Al-Mosawi, David Wexler, Andrzej Calka

Faculty of Engineering and Information Sciences - Papers: Part A

Al-based composite powders containing 2, 4, 7 and 10 volume fraction of α-Al2O3 were prepared using the uniball controlled magneto-milling method and were then uniaxially hot pressed at (600 ± 10)°C under 70 MPa for 15 min. The resulting composites were greater than 99% theoretical density with enhanced mechanical properties. Detailed characterization was performed using: X-ray diffraction, scanning electron microscopy equipped with energy dispersive spectroscopy, electrical conductivity, compression, ultra-micro indentation testing and pin on drum wear testing at ambient temperature. Microstructure-mechanical property correlations were obtained as functions of α-Al2O3 volume fraction. It was found …


High-Throughput Sheathless And Three-Dimensional Microparticle Focusing Using A Microchannel With Arc-Shaped Groove Arrays, Qianbin Zhao, Jun Zhang, Sheng Yan, Dan Yuan, Haiping Du, Gursel Alici, Weihua Li Jan 2017

High-Throughput Sheathless And Three-Dimensional Microparticle Focusing Using A Microchannel With Arc-Shaped Groove Arrays, Qianbin Zhao, Jun Zhang, Sheng Yan, Dan Yuan, Haiping Du, Gursel Alici, Weihua Li

Faculty of Engineering and Information Sciences - Papers: Part A

Sheathless particle focusing which utilises the secondary flow with a high throughput has great potential for use in microfluidic applications. In this work, an innovative particle focusing method was proposed. This method makes use of a mechanism that takes advantage of secondary flow and inertial migration. The device was a straight channel with arrays of arc-shaped grooves on the top surface. First, the mechanism and expected focusing phenomenon are explained using numerical simulation of the flow field and force balance. A simulation of particle trajectories was conducted as a reference, and then a series of experiments was designed and the …


Membership Function Based Matching Approach Of Buyers And Sellers Through A Broker In Open E-Marketplace, Dien Tuan Le, Minjie Zhang, Fenghui Ren Jan 2017

Membership Function Based Matching Approach Of Buyers And Sellers Through A Broker In Open E-Marketplace, Dien Tuan Le, Minjie Zhang, Fenghui Ren

Faculty of Engineering and Information Sciences - Papers: Part A

No abstract provided.


Bots Without Borders: How Anonymous Accounts Hijack Political Debate, Katina Michael Jan 2017

Bots Without Borders: How Anonymous Accounts Hijack Political Debate, Katina Michael

Faculty of Engineering and Information Sciences - Papers: Part A

No abstract provided.


Connection Between Trinomial Trees And Finite Difference Methods For Option Pricing With State-Dependent Switching Rates, Jingtang Ma, Hongji Tang, Song-Ping Zhu Jan 2017

Connection Between Trinomial Trees And Finite Difference Methods For Option Pricing With State-Dependent Switching Rates, Jingtang Ma, Hongji Tang, Song-Ping Zhu

Faculty of Engineering and Information Sciences - Papers: Part A

Tree approaches (binomial or trinomial trees) are very popularly used in finance industry to price financial derivatives. Such popularity stems from their simplicity and clear financial interpretation of the methodology. On the other hand, PDE (partial differential equation) approaches, with which standard numerical procedures such as the finite difference method (FDM), are characterized with the wealth of existing theory, algorithms and numerical software that can be applied to solve the problem. For a simple geometric Brownian motion model, the connection between these two approaches is studied, but it is lower-order equivalence. Moreover such a connection for a regime-switching model is …


A Degree Theory For Second Order Nonlinear Elliptic Operators With Nonlinear Oblique Boundary Conditions, Yanyan Li, Jiakun Liu, Luc Nguyen Jan 2017

A Degree Theory For Second Order Nonlinear Elliptic Operators With Nonlinear Oblique Boundary Conditions, Yanyan Li, Jiakun Liu, Luc Nguyen

Faculty of Engineering and Information Sciences - Papers: Part A

In this paper, we introduce an integer-valued degree for second order fully nonlinear elliptic operators with nonlinear oblique boundary conditions. We also give some applications to the existence of solutions of certain nonlinear elliptic equations arising from a Yamabe problem with boundary and reflector problems.


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

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 …


Linearization Of Ebt3 Film Dose Response And Virtual Film Dosimetry For Sbrt Quality Assurance, Meng Cai, Ben Archibald-Heeren, Yang Wang, Peter E. Metcalfe Jan 2017

Linearization Of Ebt3 Film Dose Response And Virtual Film Dosimetry For Sbrt Quality Assurance, Meng Cai, Ben Archibald-Heeren, Yang Wang, Peter E. Metcalfe

Faculty of Engineering and Information Sciences - Papers: Part A

EBT3 film offers high spatial resolution and low energy dependence, making it a suitable choice for quality assurance where high dose gradients are present, such as the case for SBRT. This work presents a simple method to adjust scanner settings so that dose response becomes linear. This linearity eliminates the need to obtain a calibration curve and associated uncertainties in curve fitting. Relative dosimetry can be performed after dose normalization to a reference point. Linearity is also a more robust condition than calibration curve with respect to scanner warm-up conditions, resulting in reduced uncertainty in dose measurement. An in-house developed …


The Angular Dependence Of A Two Dimensional Monolithic Detector Array For Dosimetry In Small Radiation Fields, Nauljun Stansook, Marco Petasecca, Kananan Utitsarn, Matthew Newall, Peter E. Metcalfe, Martin G. Carolan, Michael L. F Lerch, Anatoly B. Rosenfeld Jan 2017

The Angular Dependence Of A Two Dimensional Monolithic Detector Array For Dosimetry In Small Radiation Fields, Nauljun Stansook, Marco Petasecca, Kananan Utitsarn, Matthew Newall, Peter E. Metcalfe, Martin G. Carolan, Michael L. F Lerch, Anatoly B. Rosenfeld

Faculty of Engineering and Information Sciences - Papers: Part A

The purpose of this study is to investigate the directional dependence of a two dimensional monolithic detector array (M512) under 6 MV photon irradiation and to evaluate the effect of field size on angular dependence. Square fields of sizes: 3x3 cm2 and 10x10 cm2 were measured at the iso-centre of a cylindrical phantom. Beam angles with incidences from 00- 1800 in increments of 150 were used to investigate the central pixel angular response of M512, normalized to the pixel response for normal (0°) beam incidence. The angular response of the detector was compared to …


Design Of Geopolymer Concrete With Ggbfs At Ambient Curing Condition Using Taguchi Method, Muhammad N. S Hadi, Nabeel Farhan, M Neaz Sheikh Jan 2017

Design Of Geopolymer Concrete With Ggbfs At Ambient Curing Condition Using Taguchi Method, Muhammad N. S Hadi, Nabeel Farhan, M Neaz Sheikh

Faculty of Engineering and Information Sciences - Papers: Part A

In this paper, the Taguchi method has been used to design optimum mix proportions for geopolymer concrete with ground granulated blast furnace slag (GGBFS) as aluminosilicate source at ambient curing condition. The influences of binder content, alkaline activator to binder content (Al/Bi) ratio, sodium silicate to sodium hydroxide (SS/SH) ratio, and sodium hydroxide (SH) concentration on the geopolymer concrete were investigated. A total of nine mix designs were evaluated. It was found that specimens with a binder content of 450 kg/m3, Al/Bi ratio of 0.35, SS/SH ratio of 2.5, and SH concentration of 14 M produced the highest …


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 Jan 2017

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.


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 …