Browsing by Author "Blagojevic, N"
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- ItemANSTO Nuclear Foresnics Research Facility: method development and applications(Australian Nuclear Science and Technology Organisation, 2012-10-16) Wotherspoon, ATL; Hill, DM; Keegan, EA; Evans, T; Blagojevic, N; Loi, E; Toole, K; Griffiths, GJ; Smith, KL; Reinhard, MIThe IAEA defines nuclear forensic science, commonly shortened to “nuclear forensics” as ‘the scientific analysis of nuclear or other radioactive material, or of other evidence that is contaminated with radioactive material, in the context of legal proceedings, including administrative, civil, criminal or international law’1. In broad terms, the job of the nuclear forensic scientist is to support investigations that involve a nuclear security event. Nuclear forensic examinations will provide information to key questions posed by the investigative authority: What is it? How much is there? Is there any more out there? Is it ours? As an investigation proceeds other questions that may arise are; How old is it? What contaminants are present? Does it pose a threat? Who is responsible for the loss? Where did the material come from? Many of the techniques required to answer these questions are based on environmental radiochemistry. The Nuclear Forensic Research Facility (NFRF) at ANSTO is developing expertise in analysing nuclear and other radioactive material material based upon the precepts of the ‘model action plan’ of the International Technical Working Group for Nuclear Forensics (ITWG) and other best practices. We are also investigating the validity of traditional forensic techniques (like fingerprints and DNA) on evidence contaminated with radioactive material alongside more novel parameters, e.g. the isotopic composition at the ‘bulk’ material and the micro scale using advanced micro-analytical techniques. We are moving towards the integration of a range of radio analytical techniques such as mass spectrometry, electron microscopy and the simulation/modelling of material production signatures, to provide a range of different information streams to assist attribution. With each advance in our technical competencies we enhance our means to ensure the security of nuclear or other radioactive material.
- ItemCharacterization of nanocrystalline materials using different diffraction techniques(International Community for Composites Engineering, 2008-07-20) Kamarulzaman, N; Bustam, MA; Blagojevic, N; Elcombe, MM; Blackford, MG; Avdeev, M; Arof, AKNo abstract available.
- ItemComparing results of X-ray diffraction, µ-Raman spectroscopy and neutron diffraction when identifying chemical phases in seized nuclear material, during a comparative nuclear forensics exercise(Springer Nature, 2018-01-24) Rondahl, SH; Pointurier, F; Ahlinder, L; Ramebäck, H; Marie, O; Ravat, B; Delauney, F; Young, EL; Blagojevic, N; Hester, JR; Thorogood, GJ; Nelwamondo, AN; Ntsoane, TP; Roberts, SK; Holliday, KSThis work presents the results for identification of chemical phases obtained by several laboratories as a part of an international nuclear forensic round-robin exercise. In this work powder X-ray diffraction (p-XRD) is regarded as the reference technique. Neutron diffraction produced a superior high-angle diffraction pattern relative to p-XRD. Requiring only small amounts of sample, µ-Raman spectroscopy was used for the first time in this context as a potentially complementary technique to p-XRD. The chemical phases were identified as pure UO2 in two materials, and as a mixture of UO2, U3O8 and an intermediate species U3O7 in the third material. © The Author(s) 2018. This article is an open access publication.
- ItemInvestigation of cell parameters, microstructures and electrochemical behaviour of LiMn2O4 normal and nano powders(Elsevier, 2009-03-01) Kamarulzaman, N; Yusoff, RY; Kamarudin, N; Shaari, NH; Aziz, NAA; Bustam, MA; Blagojevic, N; Elcombe, MM; Blackford, MG; Avdeev, M; Arof, AKNano materials are usually difficult to prepare. This work presents a simple way of preparing LiMn2O4 nano powders using the high-energy ball milling method. This method has the advantage of producing pure, single-phase and crystalline nano powders. The milling method is carefully controlled to avoid unwanted chemical reactions that may change the stoichiometry of the material. Nano powders of between 30 and 50 nm are obtained. Structural studies of the nano powders, as well as the more-conventional micron-sized LiMn2O4, are made using X-ray diffraction and neutron diffraction methods. Electrochemical evaluation of the materials is undertaken with a three-probe cyclic voltammetry technique and galvanostatic charge-discharge measurements. Structural studies reveal that not only are the crystallites of the nano powders much reduced in size from the normal powders, but their cell parameters are also smaller. The performance characteristics of the nano material show an improvement over that of the micron-sized material by about 17% in the 1st cycle and 70.6% in the 5th cycle, at which the capacity is 132 mAh g(-1). The normal material suffers from severe capacity fading but the nano material shows much improved capacity retention. © 2008, Elsevier Ltd.
- ItemNeutron and X-ray diffraction studies of LiMn2O4 nano material and its electrochemical performance(Malaysian Nuclear Agency, 2009-06-29) Kamarulzaman, N; Yusoff, RY; Abdul Aziz, NA; Blagojevic, N; Elcombe, MM; Blackford, MG; Avdeev, MNano materials are rather difficult to study due to their tiny particle size. This work presents a simple way of preparing LiMn2O4 nano powders using the high energy ball milling method. The preparation uses highly crystalline LiMn2O4 which has been earlier synthesized and optimized using the sol-gel method. The milling method is carefully controlled to avoid unwanted chemical reactions that may change the stoichiometry of the material. Nano powders of between 30 to 50 nm are obtained. Structural studies of the nano powders as well as the more conventional micron sized LiMn2O4 are made using X-ray, neutron and selected area electron diffraction methods. Electrochemical characterization of the materials are done using a three probe cyclic voltammetry technique and galvanostatic charge-discharge measurements. It is found that the performance characteristics of the nano material show an improvement over that of the micron sized material by about 17% in the first cycle and 70.6% in the fifth cycle.
- ItemStructural changes in a commercial lithium-ion battery during electrochemical cycling: an in situ neutron diffraction study(Elsevier, 2010-12-15) Sharma, N; Peterson, VK; Elcombe, MM; Avdeev, M; Studer, AJ; Blagojevic, N; Yusoff, RY; Kamarulzaman, NThe structural response to electrochemical cycling of the components within a commercial Li-ion battery (LiCoO2 cathode, graphite anode) is shown through in situ neutron diffraction. Lithuim insertion and extraction is observed in both the cathode and anode. In particular, reversible Li incorporation into both layered and spinel-type LiCoO2 phases that comprise the cathode is shown and each of these components features several phase transitions attributed to Li content and correlated with the state-of-charge of the battery. At the anode, a constant cell voltage correlates with a stable lithiated graphite phase. Transformation to de-lithiated graphite at the discharged state is characterised by a sharp decrease in both structural cell parameters and cell voltage. In the charged state, a two-phase region exists and is composed of the lithiated graphite phase and about 64% LiC6. It is postulated that trapping Li in the solid|electrolyte interface layer results in minimal structural changes to the lithiated graphite anode across the constant cell voltage regions of the electrochemical cycle. © 2010, Elsevier Ltd.
- ItemSynchrotron x-ray microprobe analysis of radioactive trace elements in mineral sands(Elsevier Science B. V., 2001-07-21) Garrett, RF; Blagojevic, N; Cai, ZH; Legnini, DG; Rodrigues, W; Stampfl, APJElemental distribution maps and XANES spectra of radioactive trace elements in zircon and ilmenite mineral grains were measured using a synchrotron X-ray microprobe. The results confirm the utility of the technique for the study of trace elements in minerals, provide chemical information important for designing processes for their removal from ores, and are direct confirmation for a previously inferred model of thorium incorporation into ilmenite during weathering. © 2001 Elsevier Science B.V.
- ItemX-ray and neutron diffraction studies of LiMn2O4 cathode materials(X-Ray Applications Malaysia Society, 2008-07) Kamarulzaman, N; Subban, RYH; Yusoff, RY; Shaari, NH; Aziz, NAA; Bustam, MA; Blagojevic, N; Elcombe, MM; Blackford, MG; Avdeev, M; Klooster, WT; Fun, HKNo abstract available.