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Now showing 1 - 10 of 813
  • (2012) Hanaor, Dorian; Michelazzi, Marco; Leonelli, Cristina; Sorrell, Charles
    Journal Article
    The agglomeration, electrokinetic properties and electrophoretic deposition behaviour of aqueous suspensions of ZrO2 with carboxylic acid additives were studied in comparison with conventional pH adjustment. It was found that citric acid imparted negative zeta-potential values and electrosteric stabilisation to particles in suspensions at all pH levels. The examination of additions of carboxylic acids to ZrO2 suspensions revealed that these reagents cause a sharp drop in zeta-potential at distinct addition levels, which correspond to surface saturation of the particles with negatively charged carboxylate groups. Adsorption cross sections of citric acid, EDTA and oxalic acid were evaluated from these results, showing that both citric acid and EDTA coordinate to ZrO2 surfaces by two carboxylate groups while oxalic acid is coordinated by one group. The use of carboxylic acids was shown to facilitate superior electrophoretic deposition in comparison with zeta-potential modification by conventional pH adjustment through improved suspension stability.

  • (2011) Hanaor, Dorian; Michelazzi, Marco; Chenu, Jeremy; Leonelli, Cristina; Sorrell, Charles
    Journal Article
    Thick anatase films were fabricated on graphite substrates using a method of anodic aqueous electrophoretic-deposition using oxalic acid as a dispersant. Thick films were subsequently fired in air and in nitrogen at a range of temperatures. The morphology and phase composition were assessed and the photocatalytic performance was examined by the inactivation of Escherichia coli in water. It was found that the transformation of anatase to rutile is enhanced by the presence of a graphite substrate through reduction effects. The use of a nitrogen atmosphere allows higher firing temperatures, results in less cracking of the films and yields superior bactericidal performance in comparison with firing in air. The beneficial effects of a nitrogen firing atmosphere on the photocatalytic performance of the material are likely to be a result of the diffusion of nitrogen and carbon into the TiO2 lattice and the consequent creation of new valence band states.

  • (2012) Hanaor, Dorian; Karatchevtseva, Inna; Chironi, Ilkay; Triani, Gerry; Sorrell, Charles
    Journal Article
    To investigate the excess hydrolysis of titanium alkoxides, TiO2 powders were fabricated from titanium tetraisopropoxide using 6 : 1 and 100 : 1 H2O/Ti (r) ratios. The powders were dried and fired at a range of temperatures ((800uC). Hydroxylation and organic content in powders were characterised using attenuated total reflectance Fourier transform infrared spectroscopy (FTIR), laser Raman microspectroscopy and elemental microanalysis; surface area and pore size distribution were evaluated using N2 gas adsorption; phase composition was analysed using Xray diffraction (XRD) and laser Raman microspectroscopy; and crystallite size was evaluated by XRD, TEM and SEM. Results showed near complete hydrolysis in a predominantly aqueous medium (r5100), resulting in precipitated crystalline powders exhibiting brookite and anatase, which begin to transform to rutile below 500uC. The powders precipitated in a predominantly organic medium (r56) underwent partial hydrolysis, were highly porous and exhibited an amorphous structure, with the crystallisation of anatase occurring at y300uC and the transformation to rutile beginning at 500–600uC.

  • (2012) Poulos, Roslyn; Hatfield, Julie; Rissel, Chris; Grzebieta, Raphael; McIntosh, Andrew S
    Journal Article
    Introduction: There are clear personal, social and environmental benefits of cycling. However, safety concerns are among the frequently cited barriers to cycling. In Australia, there are no exposure-based measures of the rates of crash or ‘near miss’ experienced by cyclists. Design and setting: A prospective cohort study over 12 months, with all data collected via web-based online data entry. Participants: Two thousand adults aged 18 years and older, living in New South Wales (Australia), who usually bicycle at least once a month, will be recruited from March to November 2011. Methods: In the 12 months following enrolment, cyclists will be surveyed on 6 occasions (weeks 8, 16, 24, 32, 40, and 48 from the week of the enrolment survey). In these survey weeks, cyclists will be asked to provide daily reports of distance travelled; time, location and duration of trips; infrastructure used; crashes, near misses and crash-related injuries. Information on crashes and injuries will also be sought for the intervening period between the last and current survey. A subsample of participants will receive bicycle trip computers to provide objective measurement of distance travelled. Discussion: This study protocol describes the prospective cohort study developed to assess near misses, crashes and injuries among cyclists by time and distance travelled and by type of infrastructure used, with recruited participants entering data remotely using the internet. We expect to be able to calculate event rate according to exposure overall and for different infrastructure types and to report in-depth information about event causation.

  • (2010) Dall'Osso, Filippo; Dominey-Howes, Dale
    Journal Article
    Australia is at risk from tsunamis and recent work has identified the need for detailed models to assess the vulnerability of buildings to damage during tsunamis. Such models will be useful for underpinning the development of land-use zoning regulations, the identification of appropriate design standards and construction codes and in outlining community relevant tsunami disaster risk reduction strategies by local emergency managers. Such strategies might include the identification of coastal areas that require evacuation, the identification of specific buildings that might be the focus of search and rescue efforts, and the demarcation of ‘safe’ evacuation areas and structures within expected tsunami flood zones. Dall’Osso and Dominey-Howes use the results of a very high-resolution assessment of building vulnerability to tsunami (using the PTVA -3 Model) at Manly, Sydney to illustrate how vulnerability assessments could be used to enhance tsunami risk reduction.

  • (2010) Dall'Osso, Filippo; Dale, Dominey-Howes
    Journal Article
    Australia is at risk from tsunamis and recent work has identified the need for models to assess the vulnerability of exposed coastal areas – a fundamental element of the risk management process. Outputs of vulnerability assessment can be used as a baseline for the generation of tsunami pre- vention and mitigation measures, including evacuation maps. Having noted that no evacuation maps exist for Manly, Syd- ney (an area recently subjected to high resolution building vulnerability assessment by Dall’Osso et al., 2009b), we use the results of the analysis by Dall’Osso et al. (2009b) to “draft” tsunami evacuation maps that could be used by the local emergency service organisations. We then interviewed 500 permanent residents of Manly in order to gain a rapid assessment on their views about the potential usefulness of the draft evacuation maps we generated. Results of the sur- vey indicate that residents think the maps are useful and un- derstandable, and include insights that should be considered by local government planners and emergency risk manage- ment specialists during the development of official evacua- tion maps (and plans) in the future.

  • (2010) Dall'Osso, Filippo; Lorenza, Bovio; Alessandra, Cavalletti; Francesco, Immordino; Marco, Gonella; Giovanni, Gabbianelli
    Journal Article
    We present here a novel method to assess coastal vulnerability to tsunami based on GIS (Geographical Information System), ASTER imagery (Advanced Spaceborn Thermal Emission and Reflection Radiometer) and SRTM-3 elevation model (Shuttle Radar Topography Mission-3). We developed this method within the CRATER project (Coastal Risk Analysis for Tsunamis and Environmental Remediation) and applied it on the whole western coast of Thailand. As result, we generated a set of vectorial vulnerability maps with a geometrical resolution of 90m (scale 1:450 000). This approach provides a low-cost and quick tool to analyse extended coastal tracts, and prioritize investments for prevention measures or for further high-resolution analysis.

  • (2010) Dall'Osso, Filippo; Maramai, Alessandra; Graziani, Laura; Brizuela, Beatriz; Cavalletti, Alessandra; Gonella, Marco; Tinti, Stefano
    Journal Article
    The volcanic archipelago of the Aeolian Islands (Sicily, Italy) is included on the UNESCO World Heritage list and is visited by more than 200 000 tourists per year. Due to its geological characteristics, the risk related to vol- canic and seismic activity is particularly high. Since 1916 the archipelago has been hit by eight local tsunamis. The most recent and intense of these events happened on 30 De- cember 2002. It was triggered by two successive landslides along the north-western side of the Stromboli volcano (Sciara del Fuoco), which poured approximately 2–3×107 m3 of rocks and debris into the Tyrrhenian Sea. The waves im- pacted across the whole archipelago, but most of the damage to buildings and infrastructures occurred on the islands of Stromboli (maximum run-up 11 m) and Panarea. The aim of this study is to assess the vulnerability of build- ings to damage from tsunamis located within the same area inundated by the 2002 event. The assessment is carried out by using the PTVA-3 Model (Papathoma Tsunami Vulner- ability Assessment, version 3). The PTVA-3 Model calcu- lates a Relative Vulnerability Index (RVI) for every build- ing, based on a set of selected physical and structural at- tributes. Run-up values within the area inundated by the 2002 tsunami were measured and mapped by the Istituto Italiano di Geofisica e Vulcanologia (INGV) and the University of Bologna during field surveys in January 2003. Results of the assessment show that if the same tsunami were to oc- cur today, 54 buildings would be affected in Stromboli, and 5 in Panarea. The overall vulnerability level obtained in this analysis for Stromboli and Panarea are “average”/“low” and “very low”, respectively. Nonetheless, 14 buildings in Strom- Correspondence to: F. Dall’Osso (filippodallosso@gmail.com) boli are classified as having a “high” or “average” vulnera- bility. For some buildings, we were able to validate the RVI scores calculated by the PTVA-3 Model through a qualita- tive comparison with photographs taken by INGV and the University of Bologna during the post-tsunami survey. With the exception of a single structure, which is partially cov- ered by a coastal dune on the seaward side, we found a good degree of accuracy between the PTVA-3 Model forecast as- sessments and the actual degree of damage experienced by buildings. This validation of the model increases our confi- dence in its predictive capability. Given the high tsunami risk for the archipelago, our results provide a framework for pri- oritising investments in prevention measures and addressing the most relevant vulnerability issues of the built environ- ment, particularly on the island of Stromboli.

  • (2012) Olivier, Jake; Walter, Scott; Grzebieta, Raphael
    Journal Article
    Since the 1991 enactment of mandatory helmet legislation (MHL) for cyclists in New South Wales (NSW), Australia, there has been extensive debate as to its effect on head injury rates at a population level. Many previous studies have focused on the impact of MHL around the time of enactment, while little has been done to examine the ongoing effects. We aimed to extend prior work by investigating long-term trends in cyclist head and arm injuries over the period 1991–2010. The counts of cyclists hospitalised with head or arm injuries were jointly modelled with log-linear regression. The simultaneous modelling of related injury mechanisms avoids the need for actual exposure data and accounts for the effects of changes in the cycling environment, cycling behaviour and general safety improvements. Models were run separately with population counts, bicycle imports, the average weekday counts of cyclists in Sydney CBD and cycling estimates from survey data as proxy exposures. Overall, arm injuries were higher than head injuries throughout the study period, consistent with previous post-MHL observations. The trends in the two injury groups also significantly diverged, such that the gap between rates increased with time. The results suggest that the initial observed benefit of MHL has been maintained over the ensuing decades. There is a notable additional safety benefit after 2006 that is associated with an increase in cycling infrastructure spending. This implies that the effect of MHL is ongoing and progress in cycling safety in NSW has and will continue to benefit from focusing on broader issues such as increasing cycling infrastructure.

  • (2012) Hanaor, Dorian; Xu, Wanqiang; Ferry, Michael; Sorrell, Charles. C.
    Journal Article
    Abnormal grain growth (AGG) was observed in rutile TiO2 formed by the thermal treatment of anatase TiO2 in the presence of zirconium silicate. This morphological behaviour was seen to occur in sintered powder compacts and thin films with solid state zircon dopants and in TiO2 coatings on grains of zircon sand. In order to clarify the mechanism of AGG in this system, various doping methods were employed and the morphological consequences of these doping methods were investigated. It was found that doping by Zr and Si does not give rise to abnormal grain growth. The observed phenomena were discussed in terms of morphological and energetic considerations. It is likely that a distinct orientation relationship between rutile TiO2 and ZrSiO4 and possible grain boundary liquid formation play a role in giving rise to the rapid growth of faceted prismatic rutile.