Science

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Now showing 1 - 10 of 279
  • (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.

  • (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.

  • (2011) Hanaor, Dorian; Michelazzi, Marco; Veronesi, Paolo; Leonelli, Cristina; Romagnoli, Marcello; Sorrell, Charles
    Journal Article
    The dispersion of anatase phase TiO2 powder in aqueous suspensions was investigated by zeta-potential and agglomerate size analysis. The iso-electric point (IEP) of anatase was determined to be at pH 2.8 using monoprotic acids for pH adjustment. In comparison, it was found that the use of carboxylic acids, citric and oxalic, caused a decrease in zeta-potential through the adsorption of negatively charged groups to the particle surfaces. The use of these reagents was shown to enable effective anodic electrophoretic deposition (EPD) of TiO2 onto graphite substrates at low pH levels with a decreased level of bubble damage in comparison with anodic EPD from basic suspensions. The results obtained demonstrate that the IEP of TiO2 varies with the type of reagent used for pH adjustment. The low pH level of the IEP and the ability to decrease the zeta-potential through the use of carboxylic acids suggest that the anodic EPD of anatase is more readily facilitated than cathodic EPD.

  • (2011) Bednall, Timothy; Kehoe, E. James
    Journal Article
    This study examined the effectiveness of providing instructional support for the self-regulation of a self-directed homework assignment. Across four parallel experiments, university students completed an online module on critical thinking. In Experiment 1, participants who were prompted on a broad spectrum of study strategies showed superior performance on a subsequent test of application relative to a control group. In Experiment 2, participants were prompted to use two specific strategies: generation of explanations and summarization. The former improved performance, whereas the latter did not. In Experiment 3, instructional aids designed to facilitate planning improved some aspects of performance relative to the control group. In Experiment 4, attempts to encourage self-feedback impaired performance. In conclusion, beyond encouraging a broad spectrum of study strategies, the generation of explanations and planning particularly improve learning without overburdening working memory.

  • (2010) Williams, Alishia; Moulds, Michelle; Grisham, Jessica; Gay, Philippe; Lang, Tamara; Kandris, Eva; Werner-Seidler, Aliza
    Journal Article
    Study 1 evaluated the psychometric properties of the English version of the Thought Control Ability Questionnaire (TCAQ; Luciano, Algarabel, Tomás, & Martínez, 2005), an index of perceived control over intrusive cognitions. Confirmatory factor analysis in a sample of 720 University students revealed a clear uni-dimensional structure (after removal of items 5, 7, 8, 14, and 25) with high internal consistency (α = .87, 95% CI = [.86, .88]) and test-retest reliability after a six month interval (r = .68). Correlational analyses supported an inverse relationship with measures of depression, anxiety, maladaptive cognitive control strategies, and obsessive–compulsive symptomatology. Study 2 tested the ability of the TCAQ to predict successful cognitive control during an experimental suppression protocol. Results demonstrated that weak thought control ability was predictive of the frequency and associated levels of distress of a target thought while under instruction to suppress. Additionally, weak perceived thought control ability was predictive of increased efforts to suppress the target material. Collectively, results suggest that thought control ability is a measurable individual difference variable and that the TCAQ is a reliable index of perceived cognitive control.

  • (2010) Williams, Alishia; Moulds, Michelle
    Journal Article
    The current study sought to experimentally assess the differential effects of analytical ruminative processing and distraction on the experience of self-referent naturally occurring intrusive memories in a sample of dysphoric (BDI-II ≥ 12) participants. Seventy seven undergraduate participants completed a memory interview to elicit details about a self-referential intrusion and were randomly assigned to either an analytical rumination or distraction condition. Subsequent to the rumination induction, participants rated their intrusive memory as more negative, more distressing, and more evocative of a negative emotional response compared to participants who were allocated to the distraction induction. Inducing analytical rumination also resulted in participants reporting worse (i.e., more sad) mood relative to those in the distraction condition. The findings align with the suggestion that depressed individuals may get caught up in a ruminative cycle that, due to the documented effects of analytical self-focus, exacerbate the emotional response elicited by intrusions and perpetuate biased attentional focus on them. Directions for future investigations of the cognitive processes that are important in the maintenance of intrusions in depressive disorders are discussed.

  • (2010) Olivier, Jake; Norberg, Melissa
    Journal Article
    Although the normal probability distribution is the cornerstone of applying statistical methodology; data do not always meet the necessary normal distribution assumptions. In these cases, researchers often transform non normal data to a distribution that is approximately normal. Power transformations constitute a family of transformations, which include logarithmic and fractional exponent transforms. The Box-Cox method offers a simple method for choosing the most appropriate power transformation. Another option for data that is positively skewed, often used when measuring reaction times, is the Ex-Gaussian distribution which is a combination of the exponential and normal distributions. In this paper, the Box-Cox power transformation and Ex-Gaussian distribution will be discussed and compared in the context of positively skewed data. This discussion will demonstrate that the Box-Cox power transformation is simpler to apply and easier to interpret than the Ex-Gaussian distribution.