Physical Sciences and Mathematics Commons^™

Flux Distribution In Fe-Based Superconducting Materials By Magneto-Optical Imaging, Zhi Wei Lin, Jian Guo Zhu, You Guang Guo, Xiaolin Wang, S X. Dou, Tom H. Johansen, Xun Shi, K Y. Choi

Australian Institute for Innovative Materials - Papers

"This paper presents the magnetic flux distributions in Fe-based superconducting materials including single crystal of Ba(Fe_1.9Ni_0.1)As₂ and Ba(Fe_1.8Co_0.2)As₂, as well as polycrystalline SmFeO_0.75F_0.2As by means of magneto-optical imaging (MOI) technique. The single crystals were grown out of FeAs flux while polycrystalline sample was grown by hot-press. A MOI film with in-plan magnetization was used to visualize flux distributions at the sample surface. A series of magneto-optical images was taken when the samples were zero-field cooled and field cooled. The flux behavior, including penetration into and …

All-Polymer Battery System Based On Polypyrrole (Ppy)/Para (Toluene Sulfonic Acid) (Pts) And Polypyrrole (Ppy)/Indigo Carmine (Ic) Free Standing Films, Irin Sultana, Md. Mokhlesur Rahman, Jiazhao Wang, Caiyun Wang, Gordon G. Wallace, Hua-Kun Liu

Australian Institute for Innovative Materials - Papers

In this study, we introduce a novel all-polymer battery system based on conducting polymer (polypyrrole, PPy) doped with dopants of para (toluene sulfonic acid) (pTS) and indigo carmine (IC), respectively. The performance of the systems consisting of polypyrrole-para (toluene sulfonic acid) (PPy-pTS) as cathode and polypyrrole-indigo carmine (PPy-IC) as anode in conjunction with either a polymer based electrolyte or a commercial organic electrolyte of 1M LiPF₆ in a 50:50 (v/v) mixture of ethylene carbonate (EC) and dimethyl carbonate (DMC) was evaluated. In the system, all the free-standing PPy-pTS and PPy-IC films were directly …

Lifepo4-Fe2p-C Composite Cathode: An Environmentally Friendly Promising Electrode Material For Lithium-Ion Battery, M. Mahfuzur Rahman, Jiazhao Wang, Rong Zeng, David Wexler, Hua-Kun Liu

Australian Institute for Innovative Materials - Papers

In this investigation, the synthesis strategy is involved the creation of LiFePO4-Fe2P-C composites with a porous conductive architecture, which includes distinct regions or clusters containing antiferromagnetic LiFePO4 in close proximity to ferromagnetic Fe2P. The microstructure is achieved by using a simple ultra-fast solvent assisted manual grinding method, combined with solid state reaction, which can replace the time-consuming high energy ball milling method. The crystalline structure, morphology, and electrochemical characterization of the synthesised product are investigated systematically. The electrochemical performance is outstanding, especially the high C rate. The composite cathode is found to display specific capacity of 167 mAh g-1 at …

Magnetic And Superconducting Properties Of Spin-Fluctuation-Limited Superconducting Nanoscale Vnx, R Zeng, J Liu, G Du, W. X. Li, J Wang, J Horvat, S X. Dou

Australian Institute for Innovative Materials - Papers

"VNx nanoparticles and nanowires have been prepared by nitrifying V2O5 nanoparticles (NP) and nanowires (NW). The V2O5 NP and NW were synthesized by a facile hydrothermal method. Magnetic susceptibility (chi) and magnetization measurements showed long range superconducting ordering (LRSO) at the temperature of 5.8 K for NW, but there was no observation of LRSO (at least down to 2 K) for the NP sample, which is a much lower temperature than for the corresponding bulk, while both NP and NW showed the absence of long range magnetic ordering, at least down to 2 K. However, the chi data showed that …

Magnetic Properties And Microstructures Of Iron Oxide@Mesoporous Silica Core-Shell Composite For Applications In Magnetic Dye Separation, Weichang Hao, Yang Xi, Jingwei Hu, Tianmin Wang, Yi Du, X L. Wang

Australian Institute for Innovative Materials - Papers

"In this report, hollow mesoporous silica (HMS) and iron oxide-hollow mesoporous silica (FexOy@HMS) core-shell composite were prepared by a one-step facile fabrication method. Transmission electron microscopy, X-ray diffraction, N-2 adsorption-desorption isotherms, and vibrating sample magnetometer were used to characterize the morphology, microstructure, and magnetic properties of the HMS and core-shell composite. The magnetic separability of FexOy@HMS core-shell composite was tested in Rhodamine B (Rh. B) dye solution. The results indicate that the core-shell composite can absorb Rh. B dyes molecules effectively up to 90.1%. (C) 2012 American Institute of Physics. [doi:10.1063/1.3670049]"

Irradiation Si On Carbon Nanotube Paper As A Flexible Anode Material For Lithium-Ion Batteries, Shulei Chou, Mihail Ionescu, Jia-Zhao Wang, Brad Winton, Hua-Kun Liu

Australian Institute for Innovative Materials - Papers

Silicon single walled carbon nanotube composite paper was modified by low energy ion implantation using 5i to obtain a flexible composite paper. Raman and FE-SEM results show that structure of SWCNT could be destroyed by the implantation. Electrochemical measurements display that the implanted SI can improve the specific capacity and the reversible capacity of CNT paper. After 50 cycles, the specific capacity of 5Hmplanted CNT paper is 30 per cent higher than the pristine CNT.

Lightning In Superconductors, J I. Vestgarden, D.V Shantsev, Y M. Galperin, T H. Johansen

Australian Institute for Innovative Materials - Papers

Crucially important for application of type-II superconductor films is the stability of the vortex matter-magnetic flux lines penetrating the material. If some vortices get detached from pinning centres, the energy dissipated by their motion will facilitate further depinning, and may trigger a massive electromagnetic breakdown. Up to now, the time-resolved behaviour of these ultra-fast events was essentially unknown. We report numerical simulation results revealing the detailed dynamics during breakdown as within nanoseconds it develops branching structures in the electromagnetic fields and temperature, with striking resemblance of atmospheric lightning. During a dendritic avalanche the superconductor is locally heated above its critical …

Approximate Techniques For Dispersive Shock Waves In Nonlinear Media, Timothy R. Marchant, Noel F. Smyth

Australian Institute for Innovative Materials - Papers

Many optical and other nonlinear media are governed by dispersive, or diffractive, wave equations, for which initial jump discontinuities are resolved into a dispersive shock wave. The dispersive shock wave smooths the initial discontinuity and is a modulated wavetrain consisting of solitary waves at its leading edge and linear waves at its trailing edge. For integrable equations the dispersive shock wave solution can be found using Whitham modulation theory. For nonlinear wave equations which are hyperbolic outside the dispersive shock region, the amplitudes of the solitary waves at the leading edge and the linear waves at the trailing edge of …

Microporous Gel Polymer Electrolytes For Lithium Rechargeable Battery Application, Nurul Hayati Idris, Md. Mokhlesur Rahman, Jia-Zhao Wang, Hua-Kun Liu

Australian Institute for Innovative Materials - Papers

Microporous poly(vinylidene fluoride)/poly(methyl methacrylate) (PVDF/PMMA) membranes were prepared using the phase-separation method. Then, the membranes were immersed in liquid electrolyte to form polymer electrolytes. The effects of PMMA on the morphology, degree of crystallinity, porosity, and electrolyte uptake of the PVDF membrane were studied. The addition of PMMA increased the pore size, porosity and electrolyte uptake of the PVDF membrane, which in turn increased the ionic conductivity of the polymer electrolyte. The maximum ionic conductivity at room temperature was 1.21 × 10−3 S cm−1 for Sample E70. The polymer electrolyte was investigated, along with lithium iron phosphate (LiFePO4) as cathode …

Mechanism For Flux Guidance By Micrometric Antidot Arrays In Superconducting Films, J I. Vestgarden, V V. Yurchenko, R Wordenweber, T H. Johansen

Australian Institute for Innovative Materials - Papers

"A study of magnetic flux penetration in a superconducting film patterned with arrays of micron-sized antidots (microholes) is reported. Magneto-optical imaging (MOI) of a YBa(2)Cu(3)O(x) film shaped as a long strip with perpendicular antidot arrays revealed both strong guidance of flux and, at the same time, large perturbations of the overall flux penetration and flow of current. These results are compared with a numerical flux creep simulation of a thin superconductor with the same antidot pattern. To perform calculations on such a complex geometry, an efficient numerical scheme for handling the boundary conditions of the antidots and the nonlocal electrodynamics …

Magnetocapacitance Effect In Nonmultiferroic Yfe03 Single Crystal, Z X. Cheng, H Shen, J Xu, Peng Liu, S J. Zhang, Jianli Wang, Xiaolin Wang, S X. Dou

Australian Institute for Innovative Materials - Papers

YFeO3 single crystal displays two relaxor-like dielectric relaxations, one at low temperature (170300 K) and one at high temperature (370520 K), which are attributed to the activation of electrons and oxygen vacancies, respectively. Above the temperature at which electrons are activated, the sample displays a large magnetocapacitance effect. Comparison of the impedance Cole-Cole plots measured with and without applied magnetic field reveals that the occurrence of magnetocapacitance effect is accompanied with an increasing in DC conductivity under magnetic field after the activation of electrons, which is explained by the enhancement of electron jumping in Fe2b-O-Fe3b chains by magnetic field. Thus …

Room Temperature Giant And Linear Magnetoresistance In Topological Insulator Bi2te3 Nanosheets, Xiaolin Wang, Yi Du, S X. Dou, Chao Zang

Australian Institute for Innovative Materials - Papers

"Topological insulators, a new class of condensed matter having bulk insulating states and gapless metallic surface states, have demonstrated fascinating quantum effects. However, the potential practical applications of the topological insulators are still under exploration worldwide. We demonstrate that nanosheets of a Bi2Te3 topological insulator several quintuple layers thick display giant and linear magnetoresistance. The giant and linear magnetoresistance achieved is as high as over 600% at room temperature, with a trend towards further increase at higher temperatures, as well as being weakly temperature-dependent and linear with the field, without any sign of saturation at measured fields up to 13 …

The Magnetic Structure Of An Epitaxial Bimn 0.5fe 0.5o 3 Thin Film On Srtio 3 (001) Studied With Neutron Diffraction, David Laurence Cortie, A Pj Stampfl, F Klose, Y Du, Xiaolin Wang, H Zhao, H Kimura, Z Cheng

Australian Institute for Innovative Materials - Papers

High-angle neutron diffraction was used to directly reveal the atomic-scale magnetic structure of a single-crystalline BiMn 0.5 Fe 0.5 O 3 thin film deposited on a SrTiO 3 (001) substrate. The BiMn 0.5 Fe 0.5 O 3 phase exhibits distinctive magnetic properties that differentiate it from both parent compounds: BiFeO 3 and BiMnO 3. A transition to long-range G-type antiferromagnetism was observed below 120 K with a (1 2 1 2 1 2) propagation vector. A weak ferromagnetic behavior was measured at low temperature by superconducting quantum interference device (SQUID) magnetometry. There is no indication of the spin cycloid, known …

The Effects Of Annealing Temperature On The In-Field Jc And Surface Pinning In Silicone Oil Doped Mgb2 Bulks And Wires, M S. Hossain, A Motaman, O Cicek, H Agil, E Ertekin, A Gencer, Xiaolin Wang, S X. Dou

Australian Institute for Innovative Materials - Papers

No abstract provided.

Exploiting High Quality Pedot:Pss-Swnt Composite Formulations For Wet-Spinning Multifunctional Fibers, Rouhollah Jalili, Joselito M. Razal, Gordon G. Wallace

Australian Institute for Innovative Materials - Papers

In order to exploit the inherent properties of carbon nanotubes (CNT) in any polymer composite, systematic control of carbon nanotube loading and protocols that mitigate against CNT bundling are required. If such composites are to be rendered in fiber form via wet-spinning, then CNT bundling during the coagulation process must also be avoided. Here we have achieved this by utilizing highly exfoliated single walled carbon nanotubes (SWNT) and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonicacid) (PEDOT:PSS) to obtain wet-spinnable composite formulations at various nanotube volume fractions (V_f). The addition of only 0.02 V_f of aggregate-free and individually dispersed SWNT resulted in a …

In Vitro Studying Corrosion Behaviour Of Biocorrodible Mg Alloys, Sina S. Jamali, Simon Moulton, Maria Forsyth, Gordon G. Wallace

Australian Institute for Innovative Materials - Papers

The idea of bioabsorbable/biocorrodible stents has gained increasing attention in the last decade. Permanent coronary stents, traditionally made from 316L grade stainless steel, are routinely used for the treatment of blocked arteries. However, these stents can cause complications such as restenosis, thrombosis and the need for the patient to undergo prolonged antiplatelet therapy. Biodegradable metal stents provide an opportunity for the stent to remain in place for a period to ensure restoration of function and then degrade through a carefully controlled bio-corrosion process. Among the number of potentially suitable materials, Magnesium alloys have shown great promise as a stent material …

Implementing Namebers Using Microchip Implants: The Black Box Beneath The Skin, Katina Michael, M.G. Michael

Associate Professor Katina Michael

The use of electronic-based physical access cards to secure premises such as government buildings and large corporate offices has been in operation since the inception of bar code and magnetic-stripe cards in the 1970s. Over time, for secure access control, these first generation card technologies based on optical character recognition (OCR) and magnetic ink character recognition (MICR) were replaced by more sophisticated technologies such as smart cards and biometrics, containing encrypted data and techniques which were more difficult to dupe or to replicate \cite{michael2003a}.

An employee today wanting to gain access to their place of work, typically carries a photo …

Satellite Evidence For A Large Source Of Formic Acid From Boreal And Tropical Forests, T Stavrakou, J F. Muller, J Peeters, A Razavi, L Clarisse, C Clerbaux, P Coheur, D Hurtmans, M De Maziere, C Vigouroux, Nicholas Deutscher, David Griffith, Nicholas Jones, Clare Paton-Walsh

Faculty of Science - Papers (Archive)

Formic acid contributes significantly to acid rain in remote environments1, 2. Direct sources of formic acid include human activities, biomass burning and plant leaves. Aside from these direct sources, sunlight-induced oxidation of non-methane hydrocarbons (largely of biogenic origin) is probably the largest source3, 4. However, model simulations substantially underpredict atmospheric formic acid levels5, 6, 7, indicating that not all sources have been included in the models. Here, we use satellite measurements of formic acid concentrations to constrain model simulations of the global formic acid budget. According to our simulations, 100–120 Tg of formic acid is produced annually, which is two …

The Social And Behavioral Implications Of Location-Based Services, Katina Michael, M.G. Michael

Associate Professor Katina Michael

The social and behavioral implications of location-based services (LBS) are only now beginning to come to light in advanced markets where the services have been adopted by just a little over half the market (Microsoft 2011). Depending on one’s definition of what constitutes location-based services, statistics on the level of adoption differ considerably. While it is helpful to provide as broad a list of applications as possible in what constitutes LBS (e.g. everything from in-vehicle navigation systems to downloading a map using a computer), it can also cloud the real picture forming behind this emerging technology. Emerging not in the …

Monitoring People Using Location-Based Social Networking And Its Negative Impact On Trust: An Exploratory Contextual Analysis Of Five Types Of “Friend” Relationships, Sarah Fusco, Katina Michael, Anas Aloudat, Roba Abbas

Associate Professor Katina Michael

Location based social networking (LBSN) applications are part of a new suite of social networking tools. LBSN is the convergence between location based services (LBS) and online social networking (OSN). LBSN applications offer users the ability to look up the location of another “friend” remotely using a smart phone, desktop or other device, anytime and anywhere. Users invite their friends to participate in LBSN and there is a process of consent that follows. This paper explores the potential impact of LBSN upon trust in society. It looks at the willingness of individuals to share their location data with family, friends, …

Sparse Signal Decomposition For Ground Penetrating Radar, Wenbin Shao, Abdesselam Bouzerdoum, Son Lam Phung

Faculty of Informatics - Papers (Archive)

In this paper, we present an adaptive approach for sparse signal decomposition, in which each GPR trace is decomposed into elementary waves automatically. A sparse feature vector is extracted from the decomposition and used for classification of railway ballast. The experimental results show that the proposed approach can represent the GPR signals efficiently, and effective features can be extracted for pattern classification.

Power Line Enhancement For Data Monitoring Of Neural Electrical Activity In The Human Body, Ahmed M. Haidar, Sridhathan C, Abdulsalam Hazza, Ahmed Saleh

Faculty of Informatics - Papers (Archive)

Distance and real-time data monitoring are the necessary condition that makes any system in good working order. Recent advancements in micro-electronics and wireless technology enable the application of wireless sensors in both industry and wild environments. However, Long-distance wireless communication has several drawbacks like limited bandwidth, considerable costs and unstable connection quality. Therefore, Power Line Communication (PLC) using pre-established Power Lines (PL) becomes more attractive for high data transmission technology. This paper reviews the existing distance data monitoring systems and presents a case study for data transferring of temperature and heart beat measurement. The simulations were carried out on the …

A Method For Evaluating Bias In Global Measurements Of Co2 Total Columns From Space, D Wunch, P O. Wennberg, G C. Toon, B J. Connor, B Fisher, G B. Osterman, C Frankenberg, L Mandrake, C O'Dell, P Ahonen, S C. Biraud, R Castano, Noel Cressie, D Crisp, N M. Deutscher, A Eldering, M L. Fisher, David W. Griffith, M Gunson, P Heikkinen, G Keppel-Aleks, E Kyro, R Lindemaier, Ronald Macatangay, J Mendonca, J Messerschmidt, C E. Miller, I Morino, J Notholt, F A. Oyafuso, M Rettinger, J Robinson, C M. Roehl, R J. Salawitch, V Sherlock, K Strong, R Sussmann, T Tanaka, D R. Thompson, O Uchino, Thorsten Warneke, Steven C. Wofsy

Faculty of Informatics - Papers (Archive)

We describe a method of evaluating systematic errors in measurements of total column dry-air mole fractions of CO₂ (XCO₂) from space, and we illustrate the method by applying it to the v2.8 Atmospheric CO₂ Observations from Space retrievals of the Greenhouse Gases Observing Satellite (ACOS-GOSAT) measurements over land. The approach exploits the lack of large gradients in X_CO2 south of 25S to identify large-scale offsets and other biases in the ACOS-GOSAT data with several retrieval parameters and errors in instrument calibration. We demonstrate the effectiveness of the method by comparing the ACOS-GOSAT data …

Disaster Communication Governance And Public Trust: The Case Of Tepco, Akemi Takeoka Chatfield, Mary Barrett

Faculty of Informatics - Papers (Archive)

The International Risk Governance Council (IRGC) Risk Governance Framework identifies five inter-dependent phases, of which the final phase, Communication, is of the utmost importance because effective communication is the key to creating public trust in disaster risk management. Extant government reports on the 2005 Hurricane Katrina and the 2009 Victoria bushfires in Australia (2009 Victorian Bushfires Royal Commission 2010) provide evidence that disaster communication governance deficits contribute to the slow disaster response and recovery operations and the erosion of public trust in government disaster management.

The Application Of Microsimulation To Threat Modelling, Tony Green, Nicola Davies, Chris Flaherty, Ian Piper, Daniel Keep, Rachel Bunder

Faculty of Informatics - Papers (Archive)

This paper summarises the current research on the use of microsimulation and its use for understanding behaviour in modelling threat in society. The motivation for this project was to develop simulation tools that could be used to model human behaviour and overlay that behaviour with a full spectrum of threats to understand how alternative ways for undertaking prevention, protection and response could be used to reduce the risk from a threat. The basic simulation engine - Simulacron, and its associated modules are briefly described. A number of applications to biological infection, including single vector infectious disease spread, biological weapon placement …

Application Of Microsimulation Towards Modelling Of Behaviours In Complex Environments, Daniel Keep, Rachel Bunder, Ian Piper, Anthony Green

Faculty of Informatics - Papers (Archive)

In this paper, we introduce new capabilities to our existing microsimulation framework, Simulacron. These new capabilities add the modelling of behaviours based on motivations and improve our existing non-deterministic movement capacity. We then discuss the application of these new features to a simple, synthetic, proof of concept, scenario involving the transit of people through a corridor and how an induced panic affects their throughput. Finally we describe a more complex scenario, which is currently under development, involving the detonation of an explosive device in a major metropolitan transport hub at peak hour and the analysis of subsequent reaction.

Theory Of Gaussian Variational Approximation For A Poisson Mixed Model, Peter Hall, J T. Ormerod, M P. Wand

Faculty of Informatics - Papers (Archive)

Likelihood-based inference for the parameters of generalized linear mixed models is hindered by the presence of intractable integrals. Gaussian variational approximation provides a fast and effective means of approximate inference. We provide some theory for this type of approximation for a simple Poisson mixed model. In particular, we establish consistency at rate m^−1/2 +n⁻¹, where m is the number of groups and n is the number of repeated measurements.

Modelling Of Behaviours In Response To Terrorist Activity, Daniel Keep, I. Piper, A. Green, R. Bunder

Faculty of Informatics - Papers (Archive)

In this paper we present an approach to the modelling of human interaction in complex environments and its application to a security related scenario; the evacuation of a railway station subsequent to the detonation of an improvised explosive device. The intent of the experiments reported in this paper is to investigate the application of our existing software capabilities to the proof-of-concept scenario described above.Our simulation framework, Simulacron, allows the development of multiple interacting modules which address matters such as motivation, scheduling and movement, controlled both by internal goals and external influences. The ability to integrate this interaction modelling with our …

Editorial: The Social And Behavioural Implications Of Location-Based Services, Katina Michael, M G. Michael

Faculty of Informatics - Papers (Archive)

The social and behavioral implications of location-based services (LBS) are only now beginning to come to light in advanced markets where the services have been adopted by just a little over half the market (Microsoft 2011). Depending on one's definition of what constitutes location-based services, statistics on the level of adoption differ considerably. While it is helpful to provide as broad a list of applications as possible in what constitutes LBS (e.g. everything from in-vehicle navigation systems to downloading a map using a computer), it can also cloud the real picture forming behind this emerging technology. Emerging not in the …

The Fallout From Emerging Technologies: Surveillance, Social Networks And Suicide, Katina Michael, M G. Michael

Faculty of Informatics - Papers (Archive)

Saint Augustine of Hippo (354-430 CE) [1] one of the most revered doctors of the ecclesia catholica, might not have been so highly esteemed had he fl ourished centuries afterwards in a world of uberveillance [2]. One of the unique aspects of Augustine's life that endeared him to the community of the faithful, both past and present, was his rising up from the "fornications" [3] and the "delight in thievery" [4] to become a paradigm for both the eastern and western churches of the penitent who becomes a saint.