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Composition and source apportionment of fine particulate matter during extended calm periods in the city of Rijeka, Crotia
No full textIn the city of Rijeka, Croatia, an extended, two-year aerosol pollution monitoring campaignwas
recently completed. During that period, 345 samples of ne fraction of aerosols
were collected on stretched Te on lters. All samples were analyzed by Ion Beam Analysis
techniques (PIXE and PIGE) and concentrations of 22 elements were determined.
Concentrations of black carbon were determined by Laser Integrated Plate Method.
For the Bay of Kvarner, where city of Rijeka is located, common are long periods of
calm weather. As a consequence, during these periods, air pollution is steadily increasing.
To pin point and characterize local, mostly industrial, air pollution sources, we used
only samples collected during the extended calm periods. Speed of 1.5 m/s was used as
a cut-o wind speed. In this way, 188 samples were isolated and statistically evaluated
by means of Positive Matrix Factorization. The results show that the major, local pollution
sources are the following: secondary sulfates, heavy oil combustion, auto, smoke,
road dust, industry iron and port activities. As expected, natural components of aerosol
pollution such as soil and sea salt are dramatically reduced.
Keywords: Fine particles, PM2.5, Ion beam analysis, LIPM, Positive Matrix Factorization,
Air pollution sources © The Author
Exploring sediment dynamics from source to sink in the Murray-Darling basin using cosmogenic 14C, 10Be, and 26Al
No full textThe relatively short half-life of 14C, namely, 5730 years, means that, compared to the other
cosmogenic nuclides, it is substantially more sensitive to short term variations in process rates. Both
the erosion of steep mountains and the dynamics of sediment transport, storage and recycling occur
over timescales that are too short to be detectable by the cosmogenic nuclides that are currently
used routinely, namely 10Be and 26Al. In situ 14C on the other hand is ideally suited for these short
timescales, and used in combination with 26Al and 10Be, it will allow for rapid fluctuations in
process rates and/or the relatively short timescales that characterise sediment transfer and storage
to be measured accurately. The above make in situ 14C an important addition to the cosmogenic
radionuclide toolkit. We present results of in situ cosmogenic 14C system blank and calibration
sample measurements obtained with the recently established ANSTO/UOW in situ 14C extraction
system. The 14C extraction scheme follows the design of the University of Cologne, which exploits
the phase transformation of quartz to crystobalite to quantitatively extract the carbon as CO2.
Offline high-temperature furnace extraction allows a relative rapid sample throughput and can
accommodate samples ranging between 0.5 to 4 grams of clean quartz. Following extraction and
isolation, the CO2gas is graphitised using a micro-furnace and then measured using AMS similarly to
routine small radiocarbon samples. We also present results of 14C, 26Al, and 10Be analyses from
sediment samples collected from Australia’s largest river system, the Murray-Darling basin. We use
the downstream changes in the ratios of the three radionuclides in samples collected at key
locations along the rivers to quantify sediment mixing and sediment storage times in the river basin.
Substantial 26Al/10Be ‘burial’ signal is observed in downstream Murray and Darling samples, while
in situ 14C suggests complex burial-exposure histories in these samples. This could have implication
of interpreting geochemical proxies at the outlet of Murray-Darling Basin for identification of paleoclimate
driven sediment sources (i.e. Monsoon vs. Westerlies). © The Author
Neutron scattering and neutron diffraction for cultural heritage
No full textNeutron reactor and spallation source facilities provide a wide range of neutron
experimental techniques that can be employed in the characterization of cultural
heritage objects. The main advantage of neutrons is their high penetration as
they enable the non-destructive and non-invasive analysis of bulk objects deep
into their interior. In the first part of the presentation a selection of the neutron
scattering techniques, which can be traditionally offered at neutron facilities, will be covered. In the second part, an ongoing study of Carrara marble samples will
be considered in greater detail.
It is based on application of the neutron diffraction techniques such as powder
diffraction for phase analysis, texture measurement and stress analysis.
Original (residual) and temperature induced stresses distributions have been
measured in the two main phases of marble (calcite and dolomite) to study
the elastic response of the marble samples during temperature changes. This
non-destructive stress analysis is intended to elucidate possible stress-induced
mechanisms of marble deterioration caused by daily or seasonal temperature
cycling. The link of stresses to other phenomena like micro-cracking and largescale
bowing in will be also discussed. © ANST
Enhanced biocompatibility of PDMS (polydimethylsiloxane) polymer films by ion irradiation
No full textPDMS films several microns thick deposited on polished Si wafers were irradiated with Mg, Ta, and Fe in the low energy range of 40 keV to 200 keV, and for doses of 1016–1018 ions/cm2. After irradiation the films surface is self-organised into 3D coherent and semi-coherent domains. As a consequence of the surface irradiation conditions and the surface boundary conditions, some domains are highly ordered in the form of parallel waves of approximately 1 μm in height, or the result can be semi-ordered regions or disordered regions. In addition, the surface energy of the irradiated polymer is increasing, as reflected in the decrease in its surface hydrophobicity, which is beneficial for cell adhesion. The irradiated samples were tested in vivo, and the results show an increase in viable cell count of up to 650%. © 2020 Elsevier B.
The Opal Research Reactor - its status, achievements and future
No full textNot available. Physical copy available in ANSTO Library at 621.48/1
Exotic aerosols in the Falkland Islands: a record of South American dust and pollen transport to the South Atlantic since 13 ka.
No full textSouth America is thought to be a major contributor of dust to the Southern Ocean and Antarctica and therefore to affect the hemispheric energy balance and carbon cycle. However, Patagonia is an arid and deflated landscape without any continental records of dust flux. The Falkland Islands, downwind of Patagonia, offer an opportunity to recover such a record from the blanketing peat
accumulation.A short peat core taken in 2013 from East Falkland was dated by 14C, analysed by iTrax XRF scanner, LOI and DBD, and pollen analysis. The peat extends back to approximately 13 ka and ceases at around 2 ka (probably due to turf cutting). LOI and iTrax confirm a component of inorganic, siliceous minerals which we infer to be dust transported from South America. The
transport of aerosols from South America is confirmed by the presence of exotic pollen (e.g. Araucariaceae), also found by Turney et al. (2016) for the last 2.6 ka. mDust fluxes were high from 13 ka until around 10 ka and remained low except for a brief excursion around 8 ka. A similar pattern was found at a site in the Beagle Channel (Vanneste et al., 2016. Sci Reports), except that at the Falklands the post-ACR/YD decrease in dust flux was delayed by up to 1 kyr. The results support the Patagonian origin of dust to the South Atlantic and suggest a dominantly glacial origin
K, L, and M shell datasets for PIXE spectrum fitting and analysis
No full textRoutine PIXE analysis programs, like GUPIX, GEOPIXE and PIXAN generally perform at least two key functions firstly, the fitting of K, L and M characteristic lines X-ray lines to a background, including unfolding of overlapping lines and secondly, the use of a fitted primary Kα, Lα or Mα line area to determine the elemental concentration in a given matrix. To achieve these two results to better than 3–5% the data sets for fluorescence yields, emission rates, Coster–Kronig transitions and ionisation cross sections should be determined to better than 3%.
There are many different theoretical and experimental K, L and M datasets for these parameters. How they are applied and used in analysis programs can vary the results obtained for both fitting and concentration determinations. Here we discuss several commonly used datasets for fluorescence yields, emission rates, Coster–Kronig transitions and ionisation cross sections for K, L and M subshells and suggests an optimum set to obtain consistent results for PIXE analyses across a range of elements with atomic numbers from 5 ⩽ Z ⩽ 100. © 2015 Elsevier B.V
In vivo imaging of brain lesions with [11C]CLINME, a new PET radioligand of peripheral benzodiazepine receptors
No full textThe peripheral benzodiazepine receptor (PBR) is expressed by microglial cells in many neuropathologies involving neuroinflammation. PK11195, the reference compound for PBR, is used for positron emission tomography (PET) imaging but has a limited capacity to quantify PBR expression. Here we describe the new PBR ligand CLINME as an alternative to PK11195. In vitro and in vivo imaging properties of [11C]CLINME were studied in a rat model of local acute neuroinflammation, and compared with the reference compound [11C]PK11195, using autoradiography and PET imaging. Immunohistochemistry study was performed to validate the imaging data. [11C]CLINME exhibited a higher contrast between the PBR-expressing lesion site and the intact side of the same rat brain than [11C]PK11195 (2.14 ± 0.09 vs. 1.62 ± 0.05 fold increase, respectively). The difference was due to a lower uptake for [11C]CLINME than for [11C]PK11195 in the non-inflammatory part of the brain in which PBR was not expressed, while uptake levels in the lesion were similar for both tracers. Tracer localization correlated well with that of activated microglial cells, demonstrated by immunohistochemistry and PBR expression detected by autoradiography. Modeling using the simplified tissue reference model showed that R1 was similar for both ligands (R1 ∼ 1), with [11C]CLINME exhibiting a higher binding potential than [11C]PK11195 (1.07 ± 0.30 vs. 0.66 ± 0.15). The results show that [11C]CLINME performs better than [11C]PK11195 in this model. Further studies of this new compound should be carried out to better define its capacity to overcome the limitations of [11C]PK11195 for PBR PET imaging. © 2007 Wiley-Liss, Inc
Dioxo-vanadium(V), oxo-rhenium(V) and dioxo-uranium(VI) complexes with a tridentate Schiff base ligand
No full textThe complexation of a julolidine–quinoline based tridentate ligand with three oxo-metal ions, dioxo-vanadium(V), oxo-rhenium(V) and dioxo-uranium(VI), has been investigated with four new complexes being synthesised and structurally characterised. (VO2L)·2/3H2O (1) {HL (C22H21N3O) = ((E)-9-((quinolin-8-ylimino)methyl)-1,2,3,5,6,7-hexahydropyrido[3,2,1-ij]quinolin-8-ol)} has a VO2L neutral mononuclear structure with a five-fold coordinated vanadium metal centre in a distorted trigonal bipyramidal geometry. (ReOL2)2(ReCl6)·7DMF (2) [DMF = dimethylformamide] exhibits a mixed valent rhenium complex with a (ReOL2)+ cationic unit in a distorted octahedral metal coordination geometry, charge balanced with (ReCl6)2− anions. [(UO2)L(H2O)2]2·2(NO3)·HL·4H2O (3) and [(UO2)L(CH3OH)2](NO3)·CH3OH (4) both have (UO2L)+ cationic mononuclear structures with either coordinated water or methanol molecules in pentagonal bipyramidal coordination geometries for the uranium metal centres. Intra-/intermolecular interactions including hydrogen bonding and π–π interactions are common and have been discussed. In addition, optical absorption and photoluminescence properties have been investigated. © 2016 The Royal Society of Chemistr
Synthesis and characterisation of two new tripodal metalloligands incorporating zinc(II)
No full textThe in situ Schiff base condensation of 2-acetylpyrazine with tris(2-aminoethyl)amine in the presence of zinc(II) perchlorate was carried out in absolute ethanol and 95 % ethanol, respectively. Two new tripodal metalloligands, 1 and 2, were isolated. The formation of complexes 1 and 2 has been verified by NMR, mass spectral studies and X-ray (for 2), with the evidence indicating that a zinc ion is incorporated in the tripodal cavity defined by the tren backbone in each case. However the products differed in the number of Schiff base condensation reactions that had occurred. While the use of absolute ethanol resulted in condensation at all three primary amine sites of tris(2-aminoethyl)amine, employing 95 % ethanol yielded condensation at only one of the primary amine sites. These different outcomes can be ascribed, at least in part, to the effect of the different water contents in the respective reaction solvents resulting in a shift of the dynamic equilibrium involving imine formation towards the precursor amine and ketone reagents. In 1, steric considerations dictate that the three uncoordinated pyrazine nitrogen donors will have their coordination vectors oriented in a mutually divergent manner suitable for coordination to three different metal centres when acting as a metalloligand while for 2, the X-ray structure confirms that the single uncoordinated (pendent) pyrazine nitrogen is also oriented for ready coordination to a second metal centre. © 2015 Springer Science+Business Media Dordrech