UNSW@ADFA Mathematics & Physics Seminars 2009
Everyone welcome !
Seminars are usually over 40 minutes plus questions on Fridays (at 12.40 in S2, 2009) in Room P25 on the ground floor of PEMS South (Building 26 on the campus map) unless otherwise stated. Light refreshments (coffee and biscuits) served from 12.30.
A link to the 2008 program of Maths and Physics Seminars is placed here for those interested in last year's activities.
A link to the 2007 program of Maths and Physics Seminars is also placed here for those who are interested.
Next Seminar:
Monday 14 December, 11.10am, P25
(Tea, coffee and biscuits from 11:00 am)
Regional Climate Modelling of SE Australia with WRF
Presented by: Dr Jason Evans, ARC Australian Research Fellow, Climate Change Research Centre, UNSW Kensington
A 24 year regional climate simulation over south-east Australia has been performed using the Weather Research and Forecasting (WRF) model. The simulation uses 10km horizontal resolution, 30 vertical levels and is driven at the boundary by NCEP/NCAR reanalysis. Output variables are collected every 3 hours for many different variables allowing a wide range of analysis to be performed. Here I will present some evaluation of the model performance across multiple time-scales from diurnal to multi-year.
Friday 13 November, 1.40am, P25
(Tea, coffee and biscuits from 1:30 pm)
Simulation of Ocean Circulation beneath the Pine Island Glacier, Antarctica
Presented by: SBLT Scott Baxter, Oceanography Honours Student, PEMS
Ocean modelling is an important tool in understanding the processes involved within the ocean. It can be used to create simulations of the complex circulation of the water masses in the Polar Regions that arise due to interactions between the ocean, ice and atmosphere. Recently, the Pine Island Glacier (PIG) in the Amundsen Sea has been identified as undergoing the most drastic changes experienced by any region in Antarctica. The circulation of the water within this bay is believed to be the major driving force for the melting of this glacier in recent decades thus important to study. Utilising computer modelling the circulation beneath the PIG was studied with the use of newly collected bathymetry and hydrography data. The Regional Ocean Model System (ROMS), currently the most advanced terrain following sigma coordinate model, was utilised for this study. Difficulties were encountered with this new bathymetry as well as conflicts within the iceshelf component of the model. Nevertheless, preliminary simulations were completed. The model successfully recreated the inflow and outflow of water found beneath the PIG ice shelf. Both geostrophic and tidal flows are present. Tides also led to an increase in the heat flux and the freshwater melt rate experienced at the grounding line and front of the PIG ice shelf. This seminar will outline the objectives, methodologies, challenges faced and results gathered within my Oceanography Honours thesis and the scope of future work available.
Friday 6 November, 11.10am, P25
(Tea, coffee and biscuits from 11:00 am)Seminar details: the talks will be up to 25 minutes long with 5 minutes for questions.
An Assessment and Assimilation of Publicly Available Antarctic Bathymetric Compilations
Presented by: Danica Ellicott, Oceanography Honours Student, PEMS
The Southern Ocean is one of the least surveyed and explored oceans, particularly the Antarctic region below 60o south, where ship soundings are sparse due to infrequent ship traffic. Yet, knowledge of its bathymetry is essential for safe ocean navigation, for accurate simulation of climate and ocean circulation, and for the prediction of processes such as currents, internal waves, and tsunamis. Four different publicly available bathymetric compilations covering the Antarctic region were investigated and compared to ship soundings in order to evaluate their accuracy, namely; BEDMAP, GEBCO 1v2, ETOPO 1 and Topo 10.1. The criteria for this evaluation were the RMS difference and correlation against ship track data as 'ground truth'. Both the RMS differences and correlations varied with latitude and longitude, and both had the best results approximately between the latitudes 65–75oS for the majority of the bathymetric compilations. When the compilations are analysed with longitude and latitude together, there are distinct, discrete regions where one dataset outperforms the others, generally with Topo 10.1 and ETOPO 1 outperforming the other compilations. This is most likely due to the higher density of data points in this region. The BEDMAP bathymetry compilation was found to be more accurate if shifted 0.24o north in latitude. From 60–62oS, 68–76oS and 78–80oS, Topo10.1 bathymetry compilation was found to best replicate existing ship soundings; however, from 62–68oS, the ETOPO 1 compilation was found to be most accurate. Further south in the latitude band 76–78oS, Topo 10.1 has the highest correlation and ETOPO 1 has the lowest RMS difference. South of 80oS, either Adjusted BEDMAP or the ETOPO 1 compilation performs best. A regional analysis was also performed on the compilations. Generally, in the northern section of the Ross Sea, Topo 10.1 should be used, and in the southern region, ETOPO 10.1 should be used. In the Amundsen Sea, Topo 10.1 should be used, and along the West Antarctic Peninsula, both Topo 10.1 and ETOPO 1 are suitable, with GEBCO 1v2 best replicating the ship soundings along the northern tip of the West Antarctic Peninsula. Topo10.1, ETOPO 1 and BEDMAP produce bathymetric grids underneath the ice shelves; however, Topo 10.1 is limited to north of 80oS and BEDMAP to south of 65oS. In conclusion, this study shows that it is best to use a combination of Topo10.1, ETOPO 1, GEBCO 1v2 and BEDMAP bathymetry compilations for field operations and simulations requiring the most accurate bathymetry in the Antarctic region.
A Study into the Ballistics and Forensics of a Rifle
Presented by: Adam Burgess, Honours Student in Mathematics
This project contains two parts, a study into ballistics and the forensic analysis.
The ballistics part has the goal of using maths to explain the behaviour of the bullet from rest to when it hits the target. The ballistics of a rifle can be split into three clear components of the bullets flight, each are important in determining the behaviour of the round.
1) internal: behaviour of the bullet within the barrel.
2) external: the bullets projectile flight.
3) terminal: what happens to the bullet when it hits the target.
Each of the three components need to be carefully considered when producing a firearm. For example, the wrong propellant within the barrel could dramatically reduce the range and accuracy of the round (an issue that the Americans had with the original M16 assault rifle). Whilst an incorrect barrel angle could result in the round firing over the target.
The forensic component has involved working with the APF to design a process for identifying rounds that does not involve the use of expensive equipment. With the use of a digital camera and a pencil, a process for identifying the size, helix angle and land and groove width has been derived with a reasonable accuracy.
Friday 11 September, 12.40pm, P25
Models of the spread of tuberculosis
Presented by: Adam Burgess, Honours Student in Mathematics
Epidemiology is the branch of mathematics that models the distribution of diseases and their effects and severity on a population. As part of the Biological Mathematics course, my major project was to model the spread and distribution of Tuberculosis within the USA from the 1700's to now. This short presentation will detail several simple and more complex models that were examined in order to assess the on-going TB epidemic. I will compare the results of these models to historical events to indicate their success or failure to be an accurate model for this disease.
Critical times in multilayer diffusion
Presented by: Roslyn Hickson, PhD Student in Mathematics
Diffusion through multiple layers has applications to a wide range of areas in heat and mass transport. An important aspect of multilayer diffusion is the 'critical time', which is a measure of how long the diffusive process takes.
This project involves using an exact solution for multilayer diffusion to demonstrate the limitations of traditional averaging methods, which only work for a large number of layers or in the steady state. This solution is used to find a better approximation for a particular definition of critical time. The work is then extended to reaction diffusion models, with application to invasive plant spread.
Previous Seminars:
Friday 4 September, 12.40pm, P25
The seminar will be a team presentation by Ben O'Neill, Zlatko Jovanoski and Leesa Sidhu.
The show will begin with Zlatko and Leesa reflecting on the new 2nd year course "Mathematical Tools for Science" which they delivered to Physics/Oceanography and Mathematics students for the first time in Session 1, 2009. After intense consultation and a seminar delivered to PEMS in 2008, Zlatko and Leesa put together the syllabus for the course. They will share with us their experience (what worked and what didn't work so well), as well as feedback they received from students. They will also let us know their thoughts of how they will change various aspects of the course for 2010.
The second part of the seminar will be presented by Ben who has been working hard to put together the syllabus for the new 3rd year course "Methods for Data Analysis". This course will be offered to Physics/Oceanography and Mathematics students for the first time in 2010. After several rounds of feedback from Oceanography/Physics and Maths & Stats staff, Ben would like to share with PEMS his thoughts and vision for this course. He would also welcome constructive feedback and suggestions.
Friday 28 August, 1300, P25
Local lattice information from nuclear probes
Presented by: Shane Soo, 3rd year CDFSP research presentation, PEMS
Theoretical work predicts promising and truly applicable properties for GaN and ZnO based on dilute magnetic semiconductors (DMS) with Curie temperatures above room temperature. Perturbed angular correlation (PAC) spectroscopy of nuclear probes is a perfect tool to investigate the incorporation of transition metals into these compounds as well as the influence of other impurities on internal magnetic fields. This project aims to study the PAC of certain nuclear probes in GaN and ZnO. As an introduction to PAC, experiments to chart the radioactive decay of 22Na and 60Co were carried out. This presentation would cover the experiments done so far, as well as future plans for the project.
Friday 21 August, 12.40, P25
UHMWPE wear studies: 3D characterization using atomic force microscopy and cell bioactivity
Presented by: Dr Laura Gladkis, PEMS
The wear dynamics of ultra high molecular weight polyethylene (UHMWPE) and especially the effects of particulate wear debris from this material pose limits to some applications, such as knee prostheses. UHMWPE is the currently preferred material for tibial inserts in total knee arthroplasty, due to its low wear rate, excellent abrasion resistance and high mechanical stability. In spite of its favourable properties, UHMWPE wears out due to the high dynamic stresses experienced in a knee joint.
The wear debris particles generated from artificial joints provoke the release of substances that induce periprosthetic bone resorption, which leads to eventual prosthesis loosening, and subsequent revision surgery. The harmful bioactivity of these particles may depend on their size and shape. Atomic force microscopy (AFM) is proposed and explored as a technique for the characterisation of UHMWPE wear particles. AFM can measure the size and geometry of polyethylene wear particles extracted from the joint lubricant with a precision on the nanometre-scale. This can further the understanding of wear processes at this length-scale.
Particulate debris obtained from a constant load knee simulator was collected, filtered through different pore sizes filters and imaged with AFM. The volumetric size of the particles was confirmed; the particle geometry was measured and the abundance of a certain size fraction was determined. It is demonstrated that by using a lower density solution media (ethanol), UHMWPE wear particles are suspended in the solution and therefore a uniform precipitation is achieved on a filter membrane. The bioactivity of these particles has been assessed with monocytes and macrophages, results will be presented and discussed.
Friday 7 August, 12.40, P25
Radioisotope Tracing of Prosthetic Debris Pathways
Presented by: Jake Warner, PhD Student, PEMS
Polyethylene debris from knee prostheses can cause bone resorption and potential loosening of the prosthesis. This project researches the tracing of debris pathways by labelling polyethylene with radioisotopes. Debris from a model sliding wear system has been traced with the successful implantation of various radioisotopes at different depths. Future work includes bulk labelling of the entire prosthesis, as well as localized implantation in order to identify specific debris pathways across the component, as it is worn on a commercial knee simulator.
Friday 24 July at 12.40, P25
Simulation of Ocean Circulation beneath the Pine Island Glacier, Antarctica
SBLT Scott Baxter, Oceanography Honours Student, PEMS
The Pine Island Glacier (PIG) with its documented acceleration of melting, thinning and grounding line retreat is the most active of all the margins within West Antarctica. The circulation of the water masses flowing into Pine Island Bay from the Amundsen Sea are one of the mechanisms responsible for this trend. This presentation will outline my current progress on my honours thesis of utilising a configuration of the Regional Ocean Model System (ROMS) with new bathymetry and hydrographic data to simulate the water mass circulation in Pine Island Bay and beneath the iceshelf. This is in order to analyse the temperature flux of the water masses and possible internal wave generation. I will also outline my thesis thus far and the wider mechanisms involved with the bay and the global implications of the current trends associated with the PIG.
A Study into the Ballistics and Forensics of a Rifle
Adam Burgess, Mathematics Honours Student, PEMS
This project contains two parts, a study into ballistics and the forensic analysis.
The ballistics part has the goal of using maths to explain the behaviour of the bullet from rest to when it hits the target. The ballistics of a rifle can be split into three clear components of the bullets flight, each are important in determining the behaviour of the round.
1) internal: behaviour of the bullet within the barrel.
2) external: the bullets projectile flight.
3) terminal: what happens to the bullet when it hits the target.
Each of the three components need to be carefully considered when producing a firearm. For example, the wrong propellant within the barrel could dramatically reduce the range and accuracy of the round (an issue that the Americans had with the original M16 assault rifle). Whilst an incorrect barrel angle could result in the round firing over the target. So far I have been able reproduce and solve a series of equations for internal ballistics and derive equations for projectile motion in two and three dimensions.
The forensic component has involved working with the APF to design a process for identifying rounds that does not involve the use of expensive equipment. So far, with the use of a digital camera and a pencil, a process for identifying the size, helix angle and land and groove width has been derived with a reasonable accuracy. The eventual goal to be able to produce a table that could assist the APF in their forensic work.
Determination and Formation of a More Accurate Bathymetric Grid for the Antarctic through Analysis and Comparison of Publicly Available Datasets What on earth is going on down there; and how off earth can we find out?
Danica Ellicott, Oceanography Honours Student, PEMS
The Southern Ocean and in particular, the Antarctic region below 60 deg South, is the least surveyed and explored ocean. Present estimates of the bathymetry are often erroneous, with the continental shelf location in error by as much as a degree of latitude in some regions. Knowledge of the bathymetry of the Southern Ocean is essential for several reasons, including navigation and initialisation of accurate ocean models. A number of different satellite and hybrid-satellite bathymetric datasets exist for the Antarctic: GEBCO 1v2, ETOPO 1, Smith and Sandwell 10.1, and Bedmap. In order to determine the most accurate bathymetry, these datasets were compared to ship soundings. Initial analysis finds the latest Smith and Sandwell dataset the most accurate overall, probably due to its incorporation of ship sounding data into the data set. The Honours year is only part way through, however; and future analysis will determine what latitude and longitude cells are most accurate in particular regions, which will then be 'stitched' together to create a new, more accurate bathymetric grid for the Antarctic.
Friday 19 June at 11.10, P25
Presented by: Prof. Swapan Konar, Department of Applied Physics, Birla Institute of Technology, India
Photonic Crystal Fibres: Important Features and Device Applications
Photonic crystal fibres (PCF) are finding extensive use, covering area such as telecommunications, sensor technology, spectroscopy, medicine, fibre optic based devices, soliton lasers etc.
The lecture will discuss guiding of light through PCF. Fabrication techniques and some important properties associated with these fibres will be discussed. Particular attention will be paid to dispersion and nonlinear properties. A few specific designs of these fibres will be discusesed. Some important applications will be highlighted.
Friday 12 June at 11.10, P25
Presented by: Jason Sharples, PEMS
The HighFire Risk Project: a progress report
Abstract : After the severe 2003 alpine bushfires the Federal Government provided funding to the Bushfire Cooperative Research Centre for a research project specifically aimed at the problem of bushfires in high-country landscapes. As part of this broader initiative, the HighFire Risk Project was designed to provide more formal information on processes endemic to high-country landscapes that can impact significantly on the risks posed by bushfires. These processes included meteorological phenomena leading to anomalously low dew point temperatures, foehn-like winds and wind-terrain interactions. Formal investigations into the models underlying bushfire risk management were also undertaken. In this seminar I will present a broad overview of the research conducted as part of the HighFire Risk Project before discussing some of the specific research findings.
Friday 5 June 11.10, P25
Presented by: Hazar Salama , PhD Student, PEMS
Magnetic properties of the hexagonal phase manganites h-YbMnO3 and h-TmMnO3
Both the orthorhombic and the hexagonal rare earth manganites are back in the spotlight because of their multiferroic properties. That is, they exhibit both ferroelectric (spontaneous electric polarization) and antiferromagnetic (spontaneous magnetic order with zero net magnetization) behaviour at the same time and the two types of order are coupled.
The heavy rare earths ytterbium (Yb) and thulium (Tm) form manganites with the hexagonal structure. However, the orthorhombic phases were also able to be prepared under high pressure using the high pressure facilities at the ANU's Research School of Earth Sciences. Hazar has prepared both phases for these two manganites and investigated their behaviour at the atomic level using 57Fe-, 170Yb- and 169Tm-Mössbauer spectroscopy. However, in this seminar she will focus on the results she has obtained for the hexagonal phase h-YbMnO3 and h-TmMnO3.
Friday 22 May 11.10, P25
Presented by: Marshall Ward, RSES, ANU
Resonant scattering of oceanic gravity waves by balanced mesoscale eddies
Most large-scale atmospheric and oceanic flows can be decomposed into two distinct types: quasi-steady balanced currents and eddies, and smaller rapidly propagating gravity waves. The strong separation of length and time scales allows the balanced flow to evolve independently of the gravity waves, at least in some approximate sense, and has been vital to numerical modeling and forecasting efforts. There is strong observational and theoretical evidence demonstrating that gravity waves generally have a weak impact on balanced currents, but the effect of the balanced flow on gravity waves has been largely unaddressed. We look at this interaction and show that balanced currents do not directly exchange energy with the gravity wavefield, but they can induce scattering of waves into other directions. Additionally, this interaction can be explained as a resonant triad interaction caused by the nonlinear advection terms.
This work is motivated by the increasingly recognized role of tidally forced gravity waves in the regulation of the open ocean. These waves are regarded as a significant energy source for mixing, and their strong coherence is responsible for their long durations of propagation, as well as potential instabilities at specific latitudes. Most research has generally disregarded the possible impact of balanced currents and the eddy field. We show that regions of active eddy kinetic energy can disrupt these waves, leading to a more statistically incoherent wavefield and a reduced impact of tidal forcing on open ocean mixing.
Friday 1 May 11.10, P25
Presented by: Tom H. Johansen, Dept of Physics, University of Oslo, Norway, and Institute of Superconducting and Electronic Materials, University of Wollongong
Mobile Magnetic Walls as Nano-Manipulators
Controlled motion of micron and submicron sized particles is the subject of extensive ongoing research, in particular in bio-related sciences. There, digital computation based on molecules (rather than electrons) would revolutionize the abilities to control biochemical processes in nature. Recently, we found that high-mobility magnetic domain walls in ferrite garnet films (FGFs) can be excellent manipulators of small magnetic particles. Our FGFs are optically transparent, and have a large Faraday effect, allowing direct optical observation of the dynamics of both the magnetic walls and the particles experiencing the magnetic energy landscape that the domains create. In collaboration with biochemists at Florida State University, USA, we have demonstrated a number of nano-manipulators/machines such as magnetic tweezers, squeezers, stirrers, ratchets, and recently, the first digital molecular shift register, where micron-sized superparamagnetic polystyrene beads carry biomolecular cargo. In this talk I will present our work using FGFs to perform particle manipulation without mechanical guidance. This includes also studies of the magnetic behaviour of superconductors, where Abrikosov vortices (quantized magnetic flux lines) are the key players. The FGFs and the technique of magneto-optical imaging allows real-time observation of vortex dynamics, as well as manipulation of individual vortices.
Friday 17th April 11.10, P25
Presented by: Prof Nail Akhmediev, RSPhysSE, ANU.
Extreme Solitons: dangerous or useful?
The family of soliton equations is enormous. Started with the KdV equation, the soliton theory made a remarkable progress in the field of integrable equations. Nonlinear Schrödinger equation was the second in a row of being solved using the inverse scattering technique. Among many others, its solutions help us to tackle an intriguing problem of rogue waves in the ocean. These can be called "waves that appear from nowhere and disappear without a trace" (WANDT) [1]. There is a hierarchy of these solutions with increasing order and with progressively increasing amplitude. These waves can appear from smooth initial conditions and they can have virtually infinite amplitude. The final stage of evolution is their complete disappearance.
The presence of dissipation plays a crucial role in the soliton dynamics. To balance loss, the system has to have a continuous energy supply from a larger reservoir. In these conditions the system may have infinite number of fixed soliton solutions. The best example is the complex cubic-quintic Ginzburg-Landau equation (CGLE) which is basically a modified nonlinear Schrödinger equation. The set of the localized states described by the CGLE is far from being completely classified and it is unlikely that it will ever be. We are faced with the necessity to study myriads of types of solitons and countless number of bifurcations between them. One of the many fascinating features of these solitons is the increasing amount of soliton energy at certain region of the system parameters. The phenomenon can be called "dissipative soliton resonance". These solutions have variety of applications in physics, mechanics and optics. In particular, they describe generation of record high-energy pulses by laser oscillators [2].
- N. Akhmediev, A. Ankiewicz and M. Taki, Phys. Lett. A 373, 675 (2009).
- N. Akhmediev, J. M. Soto-Crespo and Ph. Grelu, Phys. Lett. A 372, 3124 (2008).
Friday 3rd April 11.10, P25
Presented by: Dr Edith M. Sevick and G.M. Wang, Research School of Chemistry, ANU.
Measuring the work of stretching a single DNA molecule and the hydrodynamic mobility of colloids near interfaces using Optical Tweezers
The Fluctuation Theorems (FTs) of Evans & Searles and of Crooks are fundamental theorems of modern thermodynamics that are suggested to be of practical use to scientists and engineers. Non-equilibrium processes with energy fluctuations on the order of kT, are described by the FTs - examples include stretching of a single DNA molecule, and translating a colloidal particle in an optical trap. Here we will present quantitative results of weak stretching of a single DNA molecule using Optical Tweezers (OT) and the analysis of this data using the FTs.
OT is the device of choice in the emerging field of micro-rheology, i.e. the study of how fluids store and dissipate mechanical energy. OT has the additional benefit that the probe is micro-positioned within small fluid volumes, so that fluids in micro-containers, such as cells, can be rheologically measured. However, miniaturisation of fluid vessels means that the vessel walls become important, and this requires that we consider the hydrodynamic interactions between the probe particle and the soft container walls. Here we will demonstrate a new OT method for measuring friction coefficient of a weakly trapped colloid particle near high surface tension interfaces, including liquid-liquid and liquid-gas interfaces.
Friday 27 March 11.10, P25
Presented by: Dr Vladimir Gubernov, I.E. Tamm Theory Department, P.N. Lebedev Physical Institute, Russian Academy of the Sciences and Visiting Fellow PEMS UNSW@ADFA
Complex wave dynamics in a chain-branching combustion model
In this work we investigate the propagation of planar combustion waves in both adiabatic and nonadiabatic model with two-step chain branching reaction mechanism. The travelling combustion wave is found to become unstable with respect to pulsating perturbations for certain parameter values. Further increase of the bifurcation parameter leads to the period doubling bifurcation cascade with emergence of pulsating solutions of period 2, 4, 8 ... and a chaotic regime of combustion wave propagation. The chaotic regime has a finite width in the parameter space and the combustion wave extinguishes when the bifurcation parameter becomes sufficiently large. The parameter values corresponding to existence of travelling wave and pulsating solutions of various periods including the chaotic regime are found. The relation between our current results and experimental observations are discussed. The prospects of future work are outlined.
Friday 20th March 11.10, P25
Presented by: Dr Kathryn Fitzsimmons, Luminescence dating laboratory, Research School of Earth Sciences, ANU
A sunburnt country: reconstructing the history of drought and aridity in Australia using luminescence
Australia is the driest inhabited continent on Earth. Aridity on the Australian continent has intensified during the glacial cycles of the last few million years, creating stony deserts, dry salt lakes, and extensive dunefields which preserve evidence of episodes of aridity. Australia is naturally a dry country, however evidence preserved in the landscape suggests that arid conditions have varied in intensity through time and space. Aridity during the last 100,000 years or so, and particularly during the last Ice Age 20,000 years ago, presided over increased aeolian activity, causing considerable expansion of desert dunefields across Australia and increased dust transport.
It is unclear how the present relatively arid, warm conditions relate to the cold, dry climate responsible for desert expansion during the last Ice Age, or to the current severe droughts. This knowledge gap is primarily due to the fact that there are few systematic records of regional aridity in Australia. The key to understanding the development of aridity is to produce a chronological framework for terrestrial aridification.
Luminescence dating – which determines when sediments were last exposed to light, based on fundamental principles of physics – is the ideal technique for tackling this research problem. Recent and continuing work at the luminescence dating laboratory at the Australian National University aims to produce such a chronological framework, focusing on key sites which preserve landscape features responsive to aridity – dunes, lake shorelines and dust deposits. Work on these different landscape features has also uncovered some interesting properties of sediments, relating to luminescence signals and sample sensitivity to environmental radiation, which suggest that varying environmental and depositional conditions may impact on the ability of sediments to emit luminescence.
Friday 13th March 11.10, P25
Presented by: Dr Jianli Wang
Characterization of Magnetic Materials – Neutron Diffraction, Magnetic and 57Fe Mössbauer Spectroscopy Studies
With the strong collaboration and support from several colleagues from the Bragg Institute, ANSTO, we have successfully applied neutron scattering to our research projects in magnetic materials. Our main focus is to elucidate critical questions - such as magnetic structure, magnetic phase transition and magnetostructural coupling - in selected magnetic materials using x-ray diffraction, magnetic, Differential Scanning Calorimetry, 57Fe Mössbauer spectroscopy and neutron diffraction measurements. With access to neutron facilities at OPAL, ANSTO and overseas (ISIS, UK; BENSC and FRM-II Germany), neutron scattering has, as expected, contributed significantly to our understanding of these cooperative magnetic phenomena.
In this presentation, I shall describe several of our recent research achievements on a range of systems including: (a) Magnetocaloric effect, magnetostructural coupling and critical magnetic behavior in FeP0.5As0.4Si0.1, Ho2Fe17-xMnx and novel RNi2Mn compounds; (b) Determination of magnetic structures, phase transitions and magnetovolume effects in
PrMn2-xFexGe2 and Pr1-xRxMn2Ge2 (R=Y or Lu) Compounds, and (c) Structural and Magnetic properties of R1-xSrxFeO3 - 57Fe Mössbauer Study among others.
Friday 20th February 11.10, P25
Presented by: Dr David Low, School of PEMS
Show and Tell: Clickers!
A joint PEMS/Business application for UNSW@ADFA Learning and Teaching funds resulted in the purchase of a number of Personal Response System (PRS) handsets, or "clickers", together with receiving hubs and software. These units are generic and open-access, allowing for a wide variety of potential applications.
This seminar will be more of an interactive show-and-tell session about the technology, rather than an academic appraisal of their usefulness (although the speaker reserves the right to limited use of the term "learning outcomes"). It is expected that after the trials in Engineering Physics 1A and Organisational Behaviour during S1-2009, the units will be made available for hire^H^H^H^H general use by colleagues.
Seminar Coordinator:
Dr John Taylor
School of PEMS
UNSW@ADFA
Canberra ACT 2600
Email: j.taylor@adfa.edu.au
Phone: (02) 6268 8813