37 resultados para Fossil wood
em Queensland University of Technology - ePrints Archive
Resumo:
Knowledge of particle emission characteristics associated with forest fires and in general, biomass burning, is becoming increasingly important due to the impact of these emissions on human health. Of particular importance is developing a better understanding of the size distribution of particles generated from forest combustion under different environmental conditions, as well as provision of emission factors for different particle size ranges. This study was aimed at quantifying particle emission factors from four types of wood found in South East Queensland forests: Spotted Gum (Corymbia citriodora), Red Gum (Eucalypt tereticornis), Blood Gum (Eucalypt intermedia), and Iron bark (Eucalypt decorticans); under controlled laboratory conditions. The experimental set up included a modified commercial stove connected to a dilution system designed for the conditions of the study. Measurements of particle number size distribution and concentration resulting from the burning of woods with a relatively homogenous moisture content (in the range of 15 to 26 %) and for different rates of burning were performed using a TSI Scanning Mobility Particle Sizer (SMPS) in the size range from 10 to 600 nm and a TSI Dust Trak for PM2.5. The results of the study in terms of the relationship between particle number size distribution and different condition of burning for different species show that particle number emission factors and PM2.5 mass emission factors depend on the type of wood and the burning rate; fast burning or slow burning. The average particle number emission factors for fast burning conditions are in the range of 3.3 x 1015 to 5.7 x 1015 particles/kg, and for PM2.5 are in the range of 139 to 217 mg/kg.
Resumo:
Maximum-likelihood estimates of the parameters of stochastic differential equations are consistent and asymptotically efficient, but unfortunately difficult to obtain if a closed-form expression for the transitional probability density function of the process is not available. As a result, a large number of competing estimation procedures have been proposed. This article provides a critical evaluation of the various estimation techniques. Special attention is given to the ease of implementation and comparative performance of the procedures when estimating the parameters of the Cox–Ingersoll–Ross and Ornstein–Uhlenbeck equations respectively.
Resumo:
'my mother is water, my father is wood' was an installation comprised of two large cork discs mounted on the gallery floor and wall, overlaid with images of photographic and archival research evidence, and a turned wood sculptural object. It also included a short video work on a miniature screen embedded in the upright disc. The work explored the language of natural elements and the structure of genealogical research to discuss the Scandinavian history of Queensland and my own family. The work was selected by the directors of LEVEL ARI in Brisbane for inclusion in their 2011 exhibitions program.
Resumo:
Divergence dating studies, which combine temporal data from the fossil record with branch length data from molecular phylogenetic trees, represent a rapidly expanding approach to understanding the history of life. National Evolutionary Synthesis Center hosted the first Fossil Calibrations Working Group (3–6 March, 2011, Durham, NC, USA), bringing together palaeontologists, molecular evolutionists and bioinformatics experts to present perspectives from disciplines that generate, model and use fossil calibration data. Presentations and discussions focused on channels for interdisciplinary collaboration, best practices for justifying, reporting and using fossil calibrations and roadblocks to synthesis of palaeontological and molecular data. Bioinformatics solutions were proposed, with the primary objective being a new database for vetted fossil calibrations with linkages to existing resources, targeted for a 2012 launch.
Resumo:
Determining the temporal scale of biological evolution has traditionally been the preserve of paleontology, with the timing of species originations and major diversifications all being read from the fossil record. However, the ages of the earliest (correctly identified) records will underestimate actual origins due to the incomplete nature of the fossil record and the necessity for lineages to have evolved sufficiently divergent morphologies in order to be distinguished. The possibility of inferring divergence times more accurately has been promoted by the idea that the accumulation of genetic change between modern lineages can be used as a molecular clock (Zuckerkandl and Pauling, 1965). In practice, though, molecular dates have often been so old as to be incongruent even with liberal readings of the fossil record. Prominent examples include inferred diversifications of metazoan phyla hundreds of millions of years before their Cambrian fossil record appearances (e.g., Nei et al., 2001) and a basal split between modern birds (Neoaves) that is almost double the age of their earliest recognizable fossils (e.g., Cooper and Penny, 1997).
Resumo:
Over the last two and a half decades, corruption in the police service in Australia has come under increased official and public scrutiny. Numerous scandals involving police officers has caused concerned about the integrity and ethics within the Police Service. This paper examines the Wood Royal Commission, specifically looking at testimony from Trevor Haken. This paper provides insights into the nature of police corruption as well as the process or ‘slippery slope’ corrupt officers go through. This paper also contributed to the existing literature by providing knowledge into the types of corruption used by police officers in real-life situations, and deepening understanding of how corruption emerges and why. It specifically confirms the literature on slippery slope arguments about police corruption and the role of trust in building a corrupt career. The paper contributes to the existing literature by providing insights into the nature of corruption used by police officers in real-life situations, and deepens the understanding of the process of corruption. The findings also contribute to our understanding that corruption is not just an individual incident but rather a result of reoccurring incidents that are generated by the nature of work, organizational structure and society in relation to corruption.
Resumo:
This paper examines the instances and motivations for noble cause corruption perpetrated by NSW police officers. Noble cause corruption occurs when a person tries to produce a just outcome through unjust methods, for example, police manipulating evidence to ensure a conviction of a known offender. Normal integrity regime initiatives are unlikely to halt noble cause corruption as its basis lies in an attempt to do good by compensating for the apparent flaws in an unjust system. This paper suggests that the solution lies in a change of culture through improved leadership and uses the political theories of Roger Myerson to propose a possible solution. Evidence from police officers in transcripts of the Wood Inquiry (1997) are examined to discern their participation in noble cause corruption and their rationalisation of this behaviour. The overall findings are that officers were motivated to indulge in this type of corruption through a desire to produce convictions where they felt the system unfairly worked against their ability to do their job correctly. We have added to the literature by demonstrating that the rewards can be positive. Police are seeking job satisfaction through the ability to convict the guilty. They will be able to do this through better equipment and investigative powers.
Resumo:
A Jacobian-free variable-stepsize method is developed for the numerical integration of the large, stiff systems of differential equations encountered when simulating transport in heterogeneous porous media. Our method utilises the exponential Rosenbrock-Euler method, which is explicit in nature and requires a matrix-vector product involving the exponential of the Jacobian matrix at each step of the integration process. These products can be approximated using Krylov subspace methods, which permit a large integration stepsize to be utilised without having to precondition the iterations. This means that our method is truly "Jacobian-free" - the Jacobian need never be formed or factored during the simulation. We assess the performance of the new algorithm for simulating the drying of softwood. Numerical experiments conducted for both low and high temperature drying demonstrates that the new approach outperforms (in terms of accuracy and efficiency) existing simulation codes that utilise the backward Euler method via a preconditioned Newton-Krylov strategy.