935 resultados para EVALUATION OF TEACHING
Resumo:
Plasma sprayable powders were prepared from ZrO2-CaO-CeO2 system using an organic binder and coated onto stainless steel substrates previously coated by a bond coat (Ni 22Cr 20Al 1.0Y) using plasma spraying. The coatings exhibited good thermal barrier characteristics and excellent resistance to thermal shock at 1000 degrees C under simulated laboratory conditions (90 half hour cycles without failure) and at 1200 degrees C under accelerated burner rig test conditions (500 2 min cycles without failure). No destabilization of cubic/tetragonal ZrO2 phase fraction occured either during the long hours (45 h cumulative) or the large number of thermal shock tests. Growth of a distinct SiO2 rich region within the ceramic was observed in the specimens thermal shock cycled at 1000 degrees C apart from mild oxidation of the bond coat. The specimens tested at 1200 degrees C had a glassy appearance on the top surface and exhibited severe oxidation of the bond coat at the ceramic-bond coat interface. The glassy appearance of the surface is due to the formation of a liquid silicate layer attributable to the impurity phase present in commercial grade ZrO2 powder. These observations are supported by SEM analysis and quantitative EDAX data.
Resumo:
Three new (dialkylamino)pyridine (DAAP)-based ligand amphiphiles 3-5 have been synthesized. All of the compounds possess a metal ion binding subunit in the form of a 2,6-disubstituted DAAP moiety. In addition, at least one ortho-CH2OH substituent is present in all the ligands. Complex formation by these ligands with various metal ions were examined under micellar conditions, but only complexes with Cu(II) ions showed kinetically potent esterolytic capacities under micellar conditions. Complexes with Cu(II) were prepared in host comicellar cetyltrimethylammonium bromide (CTABr) media at pH 7.6. Individual complexes were characterized by UV-visible absorption spectroscopy and electron paramagnetic resonance spectroscopy. These metallomicelles speed the cleavage of the substrates p-nitrophenyl hexanoate or p-nitrophenyl diphenyl phosphate. To ascertain the nature of the active esterolytic species, the stoichiometries of the respective Cu(II) complexes were determined from the kinetic version of Job's plot. In all the instances, 2:1 complex ligand/Cu(II) ion are the most kinetically competent species. The apparent pK(a) values of the Cu(II)-coordinated hydroxyl groups of the ligands 3, 4, and 5, in the comicellar aggregate, are 7.8, 8.0, and 8.0, respectively, as estimated from the rate constant vs pH: profiles of the ester cleavage reactions. The nucleophilic metallomicellar reagents and the second-order "catalytic" rate constants toward esterolysis of the substrate p-nitrophenyl hexanoate (at 25 degrees C, pH 7.6) are 37.5 for 3, 11.4 for 4, and 13.8 for 5. All catalytic systems comprising the coaggregates of 3, 4, or 5 and CTABr demonstrate turnover behavior in the presence of excess substrate.
Resumo:
Silver/metal hydride (Ag/MH) cells of about 1 Ah capacity have been fabricated and their discharge characteristics at different rates of discharge, faradaic efficiency, cycle life and a.c. impedance have been evaluated. These cells comprise metal-hydride electrodes prepared by employing similar to 60 mu m powder of an AB(2)-Laves phase alloy of nominal composition Zr0.5Ti0.5V0.6Cr0.2Ni1.2 with PTFE binder on a nickel-mesh substrate as the negative plates and commercial-grade silver electrodes as the positive plates. The cells are positive limited and exhibit two distinct voltage plateaus characteristic of two-step reduction of AgO to Ag during their low rates of discharge between C/20 and C/10. This feature is, however, absent when the cells are discharged at C/5 rate. On charging the cells to 100% of their capacity, the faradaic efficiency is found to be 100%. The impedance of the Ag/MH cell is essentially due to the impedance of the silver electrodes, since MH electrodes offer negligible impedance. The cells may be subjected to a large number of charge-discharge cycles with little deterioration.
Resumo:
A major 3-year research project to improve safety at roadworks has recently been completed by the Centre for Accident Research and Road Safety – Queensland (CARRS-Q) and industry partners. This project involved developing strategies to mitigate roadwork hazards including speeding. This paper presents three on-road evaluation studies on the effectiveness of some current and new safety treatments: use of pilot vehicles, variable message signage (VMS), police enforcement with and without VMS, and remote-controlled traffic control devices. The speed reduction potential of pilot vehicles was evaluated at a highway site. Results showed that pilot vehicles reduced average speeds within the work area, but not at a downstream location. Combinations of VMS and police enforcement were evaluated at a motorway site and results showed that police enforcement accompanied with VMS had greater effects on reducing speeds than either of these treatments alone. Three new remote-controlled traffic control devices—red and amber lights, red light and amber arrow, and a robotic stop/slow sign—were evaluated at a highway site. Results showed that the red light and amber arrow option produced consistent effects on the speeds at the approach to traffic controls and at a location inside the work area. This paper presents the first rigorous evaluations of these roadwork safety treatments in Queensland.
Resumo:
This report provides an evaluation of the implementation of the Polluter Pays Principle (PPP) – a principle of international environmental law – in the context of pollution from sugarcane farming affecting Australia’s Great Barrier Reef (GBR). The research was part of an experiment to test methods for evaluating the effectiveness of environmental laws. Overall, we found that whilst the PPP is reflected to a limited extent in Australian law (more so in Queensland law, than at the national level), the behaviour one might expect in terms of implementing the principle was largely inadequate. Evidence of a longer term, explicit commitment to the PPP was particularly weak.
Resumo:
The Coal Seam Gas (CSG) industry in Australia has grown significantly in recent years. During the gas extraction process, water is also recovered which is brackish in character. In order to facilitate beneficial reuse of the water, the CSG industry has primarily invested in Reverse Osmosis (RO) as the primary method for associated water desalination. However, the presence of alkaline earth ions in the water combined with the inherent alkalinity of the water may result in RO membrane scaling. Consequently, weak acid cation (WAC) synthetic ion exchange resins were investigated as a potential solution to this potential problem. It was shown that resins were indeed highly efficient at treating single and multi-component solutions of alkaline earth ions. The interaction of the ions with the resin was found to be considerably more complex that previously reported.
Resumo:
In order to explore the anticancer effect associated with the thiazolidinone framework, several 2-(5-((5-(4-chlorophenyl)furan-2-yl)methylene)-4-oxo-2-thioxothiazolidin-3-yl)acetic acid derivatives 5(a-1) were synthesized. Variation in the functional group at C-terminal of the thiazolidinone led to set of compounds bearing amide moiety. Their chemical structures were confirmed by H-1 NMR, IR and Mass Spectra analysis. These thiazolidinone compounds containing furan moiety exhibits moderate to strong antiproliferative activity in a cell cycle stage-dependent and dose dependent manner in two different human leukemia cell lines. The importance of the electron donating groups on thiazolidinone moiety was confirmed by MTT and Trypan blue assays and it was concluded that the 4th position of the substituted aryl ring plays a dominant role for its anticancer property. Among the synthesized compounds, 5e and 5f have shown potent anticancer activity on both the cell lines tested. To rationalize the role of electron donating group in the induction of cytotoxicity we have chosen two molecules (5e and 5k) having different electron donating group at different positions. LDH assay, Flow cytometric analysis and DNA fragmentation suggest that 5e is more cytotoxic and able to induce the apoptosis. (C) 2009 Elsevier Ltd. All rights reserved.
Resumo:
Sustainable urban development, a major issue at global scale, will become more relevant according to population growth predictions in developed and developing countries. Societal and international recognition of sustainability concerns led to the development of specific tools and procedures, known as sustainability assessments/appraisals (SA). Their effectiveness however, considering that global quality life indicators have worsened since their introduction, has promoted a re-thinking of SA instruments. More precisely, Strategic Environmental Assessment (SEA), – a tool introduced in the European context to evaluate policies, plans, and programmes (PPPs), – is being reconsidered because of several features that seem to limit its effectiveness. Over time, SEA has evolved in response to external and internal factors dealing with technical, procedural, planning and governance systems thus involving a shift of paradigm from EIA-based SEAs (first generation protocols) towards more integrated approaches (second generation ones). Changes affecting SEA are formalised through legislation in each Member State, to guide institutions at regional and local level. Defining SEA effectiveness is quite difficult. Its’ capacity-building process appears quite far from its conclusion, even if any definitive version can be conceptualized. In this paper, we consider some European nations with different planning systems and SA traditions. After the identification of some analytical criteria, a multi-dimensional cluster analysis is developed on some case studies, to outline current weaknesses.
Resumo:
Sustainable urban development, a major issue at global scale, will become more relevant according to population growth predictions in developed and developing countries. Societal and international recognition of sustainability concerns led to the development of specific tools and procedures, known as sustainability assessments/appraisals (SA). Their effectiveness however, considering that global quality life indicators have worsened since their introduction, has promoted a re-thinking of SA instruments. More precisely, Strategic Environmental Assessment (SEA), – a tool introduced in the European context to evaluate policies, plans, and programmes (PPPs), – is being reconsidered because of several features that seem to limit its effectiveness. Over time, SEA has evolved in response to external and internal factors dealing with technical, procedural, planning and governance systems thus involving a shift of paradigm from EIA-based SEAs (first generation protocols) towards more integrated approaches (second generation ones). Changes affecting SEA are formalised through legislation in each Member State, to guide institutions at regional and local level. Defining SEA effectiveness is quite difficult. Its’ capacity-building process appears quite far from its conclusion, even if any definitive version can be conceptualized. In this paper, we consider some European nations with different planning systems and SA traditions. After the identification of some analytical criteria, a multi-dimensional cluster analysis is developed on some case studies, to outline current weaknesses.
Resumo:
Australian farmers have used precision agriculture technology for many years with the use of ground – based and satellite systems. However, these systems require the use of vehicles in order to analyse a wide area which can be time consuming and cost ineffective. Also, satellite imagery may not be accurate for analysis. Low cost of Unmanned Aerial Vehicles (UAV) present an effective method of analysing large plots of agricultural fields. As the UAV can travel over long distances and fly over multiple plots, it allows for more data to be captured by a sampling device such as a multispectral camera and analysed thereafter. This would allow farmers to analyse the health of their crops and thus focus their efforts on certain areas which may need attention. This project evaluates a multispectral camera for use on a UAV for agricultural applications.
Resumo:
Robot Path Planning (RPP) in dynamic environments is a search problem based on the examination of collision-free paths in the presence of dynamic and static obstacles. Many techniques have been developed to solve this problem. Trapping in a local minima and maintaining a Real-Time performance are known as the two most important challenges that these techniques face to solve such problem. This study presents a comprehensive survey of the various techniques that have been proposed in this domain. As part of this survey, we include a classification of the approaches and identify their methods.
Resumo:
Objective This study aimed to describe the Inala Aboriginal and Torres Strait Islander Community Jury for Health Research, and evaluate its usefulness as a model of Indigenous research governance within an urban Indigenous primary health care service from the perspectives of Jury members and researchers. Methods Informed by a phenomenological approach and using narrative inquiry, a focus group was conducted with Jury members and key informant interviews were undertaken with researchers who had presented to the Community Jury in its first year of operation. Results The Jury was a site of identity work for researchers and Jury members, providing an opportunity to observe and affirm community cultural protocols. Although researchers and Jury members had differing levels of research literacy, the Jury processes enabled respectful communication and relationships to form which positively influenced research practice, community aspirations and clinical care. Discussion The Jury processes facilitated transformative research practice among researchers, and resulted in transference of power from researchers to the Jury members to the mutual benefit of both. Conclusion Ethical Indigenous health research practice requires an engagement with Indigenous peoples and knowledges at the research governance level, not simply as subjects or objects of research.
Resumo:
This paper presents three methodologies for determining optimum locations and magnitudes of reactive power compensation in power distribution systems. Method I and Method II are suitable for complex distribution systems with a combination of both radial and ring-main feeders and having different voltage levels. Method III is suitable for low-tension single voltage level radial feeders. Method I is based on an iterative scheme with successive powerflow analyses, with formulation and solution of the optimization problem using linear programming. Method II and Method III are essentially based on the steady state performance of distribution systems. These methods are simple to implement and yield satisfactory results comparable with the results of Method I. The proposed methods have been applied to a few distribution systems, and results obtained for two typical systems are presented for illustration purposes.
Resumo:
Reduced economic circumstances havemoved management goals towards higher profit, rather than maximum sustainable yields in several Australian fisheries. The eastern king prawn is one such fishery, for which we have developed new methodology for stock dynamics, calculation of model-based and data-based reference points and management strategy evaluation. The fishery is notable for the northward movement of prawns in eastern Australian waters, from the State jurisdiction of New South Wales to that of Queensland, as they grow to spawning size, so that vessels fishing in the northern deeper waters harvest more large prawns. Bioeconomic fishing data were standardized for calibrating a length-structured spatial operating model. Model simulations identified that reduced boat numbers and fishing effort could improve profitability while retaining viable fishing in each jurisdiction. Simulations also identified catch rate levels that were effective for monitoring in simple within-year effort-control rules. However, favourable performance of catch rate indicators was achieved only when a meaningful upper limit was placed on total allowed fishing effort. Themethods and findings will allow improved measures for monitoring fisheries and inform decision makers on the uncertainty and assumptions affecting economic indicators.
Resumo:
The fundamental aim in fisheries management is to determine an optimal fishing effort for sustainably harvesting from a replenishable resource. The current management objective of Australia's Northern Prawn Fishery is to maximize the long-term net economic return following Australian government policy, resulting in an average recent catch of tiger prawn species of about 1,250 tons only. However, the maximum sustainable catch stated from different studies is around 3,000-4,700 tons. We also evaluated the net profit assuming that there was no buyback scheme in 2005 and the fishing fleet was kept at 89 vessels since 2005 and concluded that 40% more catch on average (2006-2009) and an additional total profit of A$ 17 million ( excluding crew cost) could have been gained in addition to the many millions of dollars of savings in the buyback scheme. These findings have great implications for future management in Australia and elsewhere because there is a grave concern of overfishing worldwide.