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Lithium rich and deficient effects in LixCoPO4 (x=0.90, 0.95, 1, 1.05) as cathode material for lithium-ion batteries
No full textA series of LixCoPO4 (x = 0.90, 0.95, 1, 1.05) compounds with different lithium content in the starting compositions were prepared by the sol–gel method. The phase identification was carried out by X-ray diffraction and neutron diffraction. The structure, atom positions, and occupancies were characterized by neutron diffraction. The morphology of LixCoPO4 (x = 0.90, 0.95, 1, 1.05) was examined by field emission scanning electron microscopy. Electrochemical analysis indicated that Li0.95CoPO4 presented the highest discharge capacity at various current densities among all the different x value compounds. The Li0.95CoPO4 showed better cycling stability and coulombic efficiency in the room temperature ionic liquid electrolyte ([C3mpyr][NTf2] containing 1 M LiNTf2) at various current densities in the voltage range of 3.5–5.0 V than in the conventional electrolyte (1 M LiPF6 in ethylene carbonate:diethyl carbonate).© 2012, Elsevier Ltd
Constraining annual and seasonal radon-222 flux density from the Southern Ocean using radon-222 concentrations in the boundary layer at Cape Grim
Get PDFRadon concentrations measured between 2001 and 2008 in marine air at Cape Grim, a baseline site in northwestern Tasmania, are used to constrain the radon flux density from the Southern Ocean. A method is
described for selecting hourly radon concentrations that are least perturbed by land emissions and dilution by
the free troposphere. The distribution of subsequent radon flux density estimates is representative of a large
area of the Southern Ocean, an important fetch region for Southern Hemisphere climate and air pollution
studies. The annual mean flux density (0.27 mBq m 2 s 1) compares well with the mean of the limited number
of spot measurements previously conducted in the Southern Ocean (0.24 mBq m 2 s 1), and to some spot
measurements made in other oceanic regions. However, a number of spot measurements in other oceanic regions, as well as most oceanic radon flux density values assumed for modelling studies and intercomparisons,
are considerably lower than the mean reported here. The reported radon flux varies with seasons and, in summer, with latitude. It also shows a quadratic dependence on wind speed and significant wave height, as postulated and measured by others, which seems to support our assumption that the selected least perturbed
radon concentrations were in equilibrium with the oceanic radon source. By comparing the least perturbed radon observations in 2002 2003 with corresponding ‘TransCom’ model intercomparison results, the best
agreement is found when assuming a normally distributed radon flux density with s 0.075 mBq m 2 s 1. © 2013, W. Zahorowski et al
Raman spectroscopic study of natural and synthetic brannerite
No full textRaman spectra of a well-characterized natural brannerite and some synthetic brannerite samples have been collected and analysed. For the first time, all 12 theoretical Raman polyhedraof CeTi2O6 with brannerite structure have been positively identified by using quantum chemical calculations based on density functional theory (DFT) and assigned to the spectra. For synthetic samples with Y or Ca substitution on the U site and Fe substitution on the Ti site, Y–O, Fe–O and U–O vibrational modes are tentatively assigned. The U–O bond lengths for the uranyl (UO2)2+ groups, have been calculated by using the measured wavenumbers of ν1 (UO2)2+ symmetric stretching vibrations and compared with the published U–O bond lengths of a natural brannerite. © 2013 Elsevier B.V
Using local advances in fine particle source apportionment methods
No full textNot availableClean Air Society of Australia and New Zealan
INQUA 2013 1st early career researcher conference
No full textThe International Union for Quaternary Research (INQUA) is committed to developing the next generation of Quaternary Scientists. The INQUA Executive Committee has approved the inaugural INQUA Early Career Researcher inter-congress meeting to provide an avenue for MSc/PhD candidates, Post-Doctoral Researchers and research-active academics in the early stage of their careers (within 5 years of obtaining their PhD) to attend valuable workshops designed to assist ECRs with career development, to present their science and gain invaluable mentoring from more senior scientists.Australasian Quarternary Association, ANSTO, University of Wollongong
Magnetic anisotropies for tsunami deposits: application to the 3.11
Get PDFTsunami deposits consist of well-sorted fine sand intercalating with non-marine black organic mud. It is difficult to reveal
a transport direction of the deposit if the deposit showed no sedimentary fabrics,such as ripples. The proxy of anisotropy of
magnetic susceptibility (AMS) appears to be a promising tool for the study of flow fabrics in recent-tsunami deposits such as
Sumatra tsunami (Wassmer et al. 2010). The AMS fabric might allow us to reconstruct transport directions of unconsolidated
tsunami sediments during emplacement because AMS provides a cryptic alignment of ferromagnetic and paramagnetic minerals.
Such cryptic minerals, such as magnetite or phyllosilicate minerals, would behave as a different emplacement mode in a different
hydrodynamic condition. In the AMS fabrics of volcanic rocks, there are large discrepancies between the magnetic lineation
and the framework-forming silicate linear fabric. This suggests that the uncorroborated use of bulk AMS to detect flow fabric in tsunami deposits has risks. In this article, we show that the anisotropy of anhysteretic remanent magnetization (AARM) may resolve the difficulties. The combination of inundation eye-witness, SEM, AMS, and AARM confirms the flow pattern of recentand
paleo-tsunami deposits from the geoslicer sampleing at Rikuzen-Takata city, Japan during 2011, 11th March Tohoku tsunami.
We determined if the sandy deposits are of tsunami from these magnetic anisotropies. © 2013, Japan Geoscience Union
Key experimental M subshell line X-ray production cross sections for slow light ions on high atomic number targets compared with the ECUSAR theory
Get PDFThe x-ray production cross sections for dominant lines in each of the five M subshells have been measured for slow proton and helium ion impact on selected high atomic number targets from tungsten to
uranium. Proton energies between 0.5 and 3 MeV and helium ion energies between 0.5 and 2 MeV were used providing M subshell cross sections for 0.3 < x < 3, where x = v /(q v ), as defined by Brandt and Mi s 1 s 2s
Lapicki 1979, distinguishes between slow (x 1) collision regimes. s s
Ion energies and targets over these ranges cover the commonly used PIXE range for M subshell x-ray production on heavy targets across the x-ray energy range 1.3-6 keV, which has a strong overlap with key
common K shell elements from Al to Fe. Hence it is important for frequently used PIXE analysis programs like GUPIX and GEOPIXE to have a consistent set of M subshell cross sections together with subshell parameters, like fluorescence yields and Coster-Kronig transition rates, which will precisely and
accurately predict M shell line intensities over this low energy X-ray region of interest
A 1,500 year south Australian rainfall record based on speleothem hydrological proxies
No full textCave drip water studies at Wombeyan Caves (34°19’S, 149°59’E) demonstrated a marked hydrochemical response to wet/dry phases (McDonald Et al. 2004; 2007). Geochemical Variations in three 20th Century coeval active Speleothems were able to be linked to the instrumental record. Subsequently geochemical relationships were investigated in a long record speleothem(WM7) which grew deeper within the same cave system. Obtaining a robust chronology proved to be challenging, due to the young age of the speleothem and very low uranium concentrations (~10 ppb) the use of U‚Aeseries disequilibrium dating was ineffective to produce a robust chronology. Chronology for WM7 was based on a dense sequence of DCF corrected ages using three different age-‐depth models: Clam (Classical method), and Bacon and OxCal (Bayesian statistical approach) (Hua et al. 2012).The new chronology indicated that WM7 began growth around 4400 cal BP(171 mm). However, since sampling from 0-‐50mm was most intensive, the model is based on this part of the stalagmite and indicates that the top 50 mm of WM7 grew during the past 1360 and 1740 years. An aridity index based on Sr,P, Y, La, and Ba shows that over the last 1,500 years several sustained episodes of wet/arid and otherwise variable phases have occurred. Two sustained wet phases ~ 700-‐880
AD and ~ 900-‐ 1250 AD were followed by ~ 400 years of variable wet/dry conditions, although from ~1300 to 1600 AD a drying trend is indicated, but punctuated by several wetter
episodes. The last 200 years indicate sustained drying phases. The OE￥13C record is anomalous from ~ 1880 to present and attributed to the stalagmite’s recording of increasing contribution of fossil fuel to CO2 concentrations. Within the longer-‐time scale oscillations, higher resolution (~ 2-‐5 years) variability is evident, replicating the trend shown by modern annually resolved stalagmites at this site
Diffuse scattering study of short-range order in lead zinc niobate
No full textLead zinc niobate (PZN) is an important ferroelectric and piezoelectric material, being one of the most commonly used materials for this purpose. The main aim of the project was to investigate the nanostructure of PZN using various scattering techniques; to gain a better understanding of the short-range order of the nanostructure and how it evolves with temperature. The diffuse scattering from lead zinc niobate (PZN) was collected and analysed from both powder and single crystal samples at a range of temperatures. The data collection and processing techniques were developed in order to allow collection of high quality single crystal diffuse scattering (SCDS) from the powder diffractometer Wombat at the Australian Nuclear Science and Technology Organisation (ANSTO). The evolution of the diffuse scattering with temperature was analysed. Results presented in this work show the evolution of the diffuse rods of scattering (a result of the planar nanodomain structure), the scattering as a result of size-effect relaxation and the short-range chemical ordering of the B-site atoms, Zn and Nb. The size-effect was observed to undergo a rapid change in intensity at around the Curie temperature, although all the other feature evolve slowly across the transition. This implies that the size-effect relaxation could be related to the ferroelectric properties. The SCDS was modelled using Monte Carlo (MC) simulations as a method to induce short-range order into the system. The B-site ordering used an Ising energy, while to induce the planar nanodomain formation an artificial MC energy is required. The development of the Global Instability Index (GII), which is the normalised sum of the square of the difference between expected and calculated bond valence parameters, as an MC energy term was done in order to induce the short-range order of the non-Pb atoms in the model in a chemically realistic manner. The final study used Total Scattering data which were collected using both X-rays and neutrons. The PDF data analysis of this data was performed using both a full-profile fitting approach and the reverse Monte Carlo (RMC) refinement of a larger model. The qualitative analysis of the PDF data showed that a lead displacement direction of is closest to what is observed in the data. There were also observed to be different separation distances between the two different B-site atoms and the neighbouring O atoms. This is information that can not be as easily determined from the single crystal data. The evolution of the PDF data with temperature was also analysed. The RMC refinement produced very precise fits to the data and provided a small amount of insight to the short-range order. The comparison of the PDF and SCDS techniques gave insight to the advantages and disadvantages of the different techniques for analysis of diffuse scattering, and showed that while the PDF data is sensitive to the Pb atom displacements, it is not sensitive to the formation of the planar nanodomains
Environmental context for late holocene human occupation of the South Wellesley Archipelago, Gulf of Carpentaria, northern Australia
No full textA 2400 year record of environmental change is reported from a wetland on Bentinck Island in the southern Gulf of Carpentaria, northern Australia. Three phases of wetland development are identified, with a protected coastal setting from ca. 2400 to 500 years ago, transitioning into an estuarine mangrove forest from ca. 500 years ago to the 1940s, and finally to a freshwater swamp over the past +60 years. This sequence reflects the influence of falling sea-levels, development of a coastal dune barrier system, prograding shorelines, and an extreme storm (cyclone) event. In addition, there is clear evidence of the impacts that human abandonment and resettlement have on the island's fire regimes and vegetation. A dramatic increase in burning and vegetation thickening was observed after the cessation of traditional Indigenous Kaiadilt fire management practices in the 1940s, and was then reversed when people returned to the island in the 1980s. In terms of the longer context for human occupation of the South Wellesley Archipelago, it is apparent that the mangrove phase provided a stable and productive environment that was conducive for human settlement of this region over the past 1000 years. © 2015 Published by Elsevier Ltd