881 resultados para Transport and Eco-hydraulic Modelling
Resumo:
Road traffic injuries are one of the major public health burdens worldwide. The United Nations Decade of Action for Road Safety (2011-2020) implores all nations to work to reduce this burden. This decade represents a unique and historic period of time in the field of road safety. Information exchange and co-operation between nations is an important step in achieving the goal. The burden of road crashes, fatalities and injuries is not equally distributed. We know that low and middle-income countries experience the majority of the road trauma burden. Therefore it is imperative that these countries learn from the successes of others that have developed and implemented road safety laws, public education campaigns and countermeasures over many years and have achieved significant road trauma reductions as a result. China is one of the countries experiencing a large road trauma burden. Vulnerable road users such as pedestrians and cyclists make up a large proportion of fatalities and injuries in China. Speeding, impaired/drug driving, distracted driving, vehicle overloading, inadequate road infrastructure, limited use of safety restraints and helmets, and limited road safety training have all been identified as contributing to the problem. Some important steps have been taken to strengthen China’s approach, including increased penalties for drunk driving in May 2011 and increased attention to school bus safety in 2011/12. However, there is still a large amount of work needed to improve the current road safety position in China. This paper provides details of a program to assist with road safety knowledge exchange between China and Australia that was funded by the Australian Government which was undertaken in the latter part of 2012. The four month program provided the opportunity for the first author to work closely with key agencies in Australia that are responsible for policy development and implementation of a broad range of road safety initiatives. In doing so, an in-depth understanding was gained about key road safety strategies in Australia and processes for developing and implementing them. Insights were also gained into the mechanisms used for road safety policy development, implementation and evaluation in several Australian jurisdictions. Road traffic law and enforcement issues were explored with the relevant jurisdictional transport and police agencies to provide a greater understanding of how Chinese laws and practices could be enhanced. Working with agencies responsible for public education and awareness campaigns about road safety in Australia also provided relevant information about how to promote road safety at the broader community level in China. Finally, the program provided opportunities to work closely with several world-renowned Australian research centres and key expert researchers to enhance opportunities for ongoing road safety research in China. The overall program provided the opportunity for the first author to develop knowledge in key areas of road safety strategy development, implementation and management which are directly relevant to the current situation in China. This paper describes some main observations and findings from participation in the program.
Resumo:
Philosophical inquiry in the teaching and learning of mathematics has received continued, albeit limited, attention over many years (e.g., Daniel, 2000; English, 1994; Lafortune, Daniel, Fallascio, & Schleider, 2000; Kennedy, 2012a). The rich contributions these communities can offer school mathematics, however, have not received the deserved recognition, especially from the mathematics education community. This is a perplexing situation given the close relationship between the two disciplines and their shared values for empowering students to solve a range of challenging problems, often unanticipated, and often requiring broadened reasoning. In this article, I first present my understanding of philosophical inquiry as it pertains to the mathematics classroom, taking into consideration the significant work that has been undertaken on socio-political contexts in mathematics education (e.g., Skovsmose & Greer, 2012). I then consider one approach to advancing philosophical inquiry in the mathematics classroom, namely, through modelling activities that require interpretation, questioning, and multiple approaches to solution. The design of these problem activities, set within life-based contexts, provides an ideal vehicle for stimulating philosophical inquiry.
Resumo:
The number of office building retrofit projects is increasing. These projects are characterised by processes which have a close relationship with waste generation and therefore demand a high level of waste management. In a preliminary study reported separately, we identified seven critical factors of on-site waste generation in office building retrofit projects. Through semi-structured interviews and Interpretive Structural Modelling, this research further investigated the interrelationships among these critical waste factors, to identify each factor’s level of influence on waste generation and propose effective solutions for waste minimization. “Organizational commitment” was identified as the fundamental issue for waste generation in the ISM system. Factors related to plan, design and construction processes were found to be located in the middle levels of the ISM model but still had significant impacts on the system as a whole. Based on the interview findings and ISM analysis results, some practical solutions were proposed for waste minimization in building retrofit projects: (1) reusable and adaptable fit-out design; (2) a system for as-built drawings and building information; (3) integrated planning for retrofitting work process and waste management; and (4) waste benchmarking development for retrofit projects. This research will provide a better understanding of waste issues associated with building retrofit projects and facilitate enhanced waste minimization.
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The global financial crisis (GFC) in 2008 rocked local, regional, and state economies throughout the world. Several intermediate outcomes of the GFC have been well documented in the literature including loss of jobs and reduced income. Relatively little research has, however, examined the impacts of the GFC on individual level travel behaviour change. To address this shortcoming, HABITAT panel data were employed to estimate a multinomial logit model to examine mode switching behaviour between 2007 (pre-GFC) and 2009 (post-GFC) of a baby boomers cohort in Brisbane, Australia—a city within a developed country that has been on many metrics the least affected by the GFC. In addition, a Poisson regression model was estimated to model the number of trips made by individuals in 2007, 2008, and 2009. The South East Queensland Travel Survey datasets were used to develop this model. Four linear regression models were estimated to assess the effects of the GFC on time allocated to travel during a day: one for each of the three travel modes including public transport, active transport, less environmentally friendly transport; and an overall travel time model irrespective of mode. The results reveal that individuals were more likely to switch to public transport who lost their job or whose income reduced between 2007 and 2009. Individuals also made significantly fewer trips in 2008 and 2009 compared to 2007. Individuals spent significantly less time using less environmentally friendly transport but more time using public transport in 2009. Baby boomers switched to more environmentally friendly travel modes during the GFC.
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Exact solutions of partial differential equation models describing the transport and decay of single and coupled multispecies problems can provide insight into the fate and transport of solutes in saturated aquifers. Most previous analytical solutions are based on integral transform techniques, meaning that the initial condition is restricted in the sense that the choice of initial condition has an important impact on whether or not the inverse transform can be calculated exactly. In this work we describe and implement a technique that produces exact solutions for single and multispecies reactive transport problems with more general, smooth initial conditions. We achieve this by using a different method to invert a Laplace transform which produces a power series solution. To demonstrate the utility of this technique, we apply it to two example problems with initial conditions that cannot be solved exactly using traditional transform techniques.
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This PhD research investigates the critical resources and Internet capabilities utilized by firms for leveraging global performance in entrepreneurial firms. Firm resources have been identified as important firm assets, which contribute to the firm's competitive global position. The Internet is a critical resource for a new generation of small and medium sized enterprise (SME) in pursuing international opportunities. By facilitating international business, the Internet has the ability to increase the quality and speed of communications, lower transaction costs, and facilitate the development of networks. Despite the increasing numbers of firms utilizing the Internet to pursue international opportunities, limited research remains. Adopting multiple case study methodology and structural equation modelling, the research identified the firm-level resources, which coincide with capabilities in a model predicting how international performance in firms is achieved.
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This chapter addresses data modelling as a means of promoting statistical literacy in the early grades. Consideration is first given to the importance of increasing young children’s exposure to statistical reasoning experiences and how data modelling can be a rich means of doing so. Selected components of data modelling are then reviewed, followed by a report on some findings from the third-year of a three-year longitudinal study across grades one through three.
Resumo:
IODP Expedition 339 drilled five sites in the Gulf of Cadiz and two off the west Iberian margin (November 2011 to January 2012), and recovered 5.5 km of sediment cores with an average recovery of 86.4%. The Gulf of Cadiz was targeted for drilling as a key location for the investigation of Mediterranean outflow water (MOW) through the Gibraltar Gateway and its influence on global circulation and climate. It is also a prime area for understanding the effects of tectonic activity on evolution of the Gibraltar Gateway and on margin sedimentation. We penetrated into the Miocene at two different sites and established a strong signal of MOW in the sedimentary record of the Gulf of Cadiz, following the opening of the Gibraltar Gateway. Preliminary results show the initiation of contourite deposition at 4.2–4.5 Ma, although subsequent research will establish whether this dates the onset of MOW. The Pliocene succession, penetrated at four sites, shows low bottom current activity linked with a weak MOW. Significant widespread unconformities, present in all sites but with hiatuses of variable duration, are interpreted as a signal of intensified MOW, coupled with flow confinement. The Quaternary succession shows a much more pronounced phase of contourite drift development, with two periods of MOW intensification separated by a widespread unconformity. Following this, the final phase of drift evolution established the contourite depositional system (CDS) architecture we see today. There is a significant climate control on this evolution of MOW and bottom-current activity. However, from the closure of the Atlantic–Mediterranean gateways in Spain and Morocco just over 6 Ma and the opening of the Gibraltar Gateway at 5.3 Ma, there has been an even stronger tectonic control on margin development, downslope sediment transport and contourite drift evolution. The Gulf of Cadiz is the world's premier contourite laboratory and thus presents an ideal testing ground for the contourite paradigm. Further study of these contourites will allow us to resolve outstanding issues related to depositional processes, drift budgets, and recognition of fossil contourites in the ancient record on shore. The expedition also verified an enormous quantity and extensive distribution of contourite sands that are clean and well sorted. These represent a relatively untapped and important exploration target for potential oil and gas reservoirs.
Resumo:
Providing mobility corridors for communities, enabling freight networks to transport goods and services, and a pathway for emergency services and disaster relief operations, roads are a vital component of our societal system. In the coming decades, a number of modern issues will face road agencies as a result of climate change, resource scarcity and energy related challenges that will have implications for society. To date, these issues have been discussed on a case by case basis, leading to a fragmented approach by state and federal agencies in considering the future of roads – with potentially significant cost and risk implications. Within this context, this paper summarises part of a research project undertaken within the ‘Greening the Built Environment’ program of the Sustainable Built Environment National Research Centre (SBEnrc, Australia), which identified key factors or ‘trends’ affecting the future of roads and key strategies to ensure that road agencies can continue to deliver road infrastructure that meets societal needs in an environmentally appropriate manner. The research was conducted over two years, including a review of academic and state agency literature, four stakeholder workshops in Western Australia and Queensland, and industry consultation. The project was supported financially and through peer review and contribution, by Main Roads Western Australia, QLD Department of Transport and Main Roads, Parsons Brinckerhoff, John Holland Group, and the Australian Green Infrastructure Council (AGIC). The project highlighted several potential trends that are expected to affect road agencies in the future, including predicted resource and materials shortages, increases in energy and natural resources prices, increased costs related to greenhouse gas emissions, changing use and expectations of roads, and changes in the frequency and intensity of weather events. Exploring the implications of these potential futures, the study then developed a number of strategies in order to prepare transport agencies for the associated risks that such trends may present. An unintended outcome of the project was the development of a process for enquiring into future scenarios, which will be explored further in Stage 2 of the project (2013-2014). The study concluded that regardless of the type and scale of response by the agency, strategies must be holistic in approach, and remain dynamic and flexible.
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A non-translating, long duration thunderstorm downburst has been simulated experimentally and numerically by modelling a spatially stationary steady flow impinging air jet. Velocity profiles were shown to compare well with an upper-bound of velocity measurements reported for full-scale microbursts. Velocity speed-up over a range of topographic features in simulated downburst flow was also tested with comparisons made to previous work in a similar flow, and also boundary layer wind tunnel experiments. It was found that the amplification measured above the crest of topographic features in simulated downburst flow was up to 35% less than that observed in boundary layer flow for all shapes tested. From the computational standpoint we conclude that the Shear Stress Transport (SST) model performs the best from amongst a range of eddy-viscosity and second moment closures tested for modelling the impinging jet flow.
Resumo:
Portable water-filled barriers (PWFBs) are roadside appurtenances that prevent vehicles from penetrating into temporary construction zones on roadways. PWFBs are required to satisfy the strict regulations for vehicle re-direction in tests. However, many of the current PWFBs fail to re-direct the vehicle at high speeds due to the inability of the joints to provide appropriate stiffness. The joint mechanism hence plays a crucial role in the performance of a PWFB system at high speed impacts. This paper investigates the desired features of the joint mechanism in a PWFB system that can re-direct vehicles at high speeds, while limiting the lateral displacement to acceptable limits. A rectangular “wall” representative of a 30 m long barrier system was modeled and a novel method of joining adjacent road barriers was introduced through appropriate pin-joint connections. The impact response of the barrier “wall” and the vehicle was obtained and the results show that a rotational stiffness of 3000 kNm/rad at the joints seems to provide the desired features of the PWFB system to re-direct impacting vehicles and restrict the lateral deflection. These research findings will be useful to safety engineers and road barrier designers in developing a new generation of PWFBs for increased road safety.
Resumo:
Accurate prediction of incident duration is not only important information of Traffic Incident Management System, but also an ffective input for travel time prediction. In this paper, the hazard based prediction odels are developed for both incident clearance time and arrival time. The data are obtained from the Queensland Department of Transport and Main Roads’ STREAMS Incident Management System (SIMS) for one year ending in November 2010. The best fitting distributions are drawn for both clearance and arrival time for 3 types of incident: crash, stationary vehicle, and hazard. The results show that Gamma, Log-logistic, and Weibull are the best fit for crash, stationary vehicle, and hazard incident, respectively. The obvious impact factors are given for crash clearance time and arrival time. The quantitative influences for crash and hazard incident are presented for both clearance and arrival. The model accuracy is analyzed at the end.
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There are currently more than 700 cities operating bike share programs. Purported benefits of bike share include flexible mobility, physical activity, reduced congestion, emissions and fuel use. Implicit or explicit in the calculation of program benefits are assumptions regarding the modes of travel replaced by bike share journeys. This paper examines the degree to which car trips are replaced by bike share, through an examination of survey and trip data from bike share programs in Melbourne, Brisbane, Washington, D.C., London, and Minneapolis/St. Paul. A secondary and unique component of this analysis examines motor vehicle support services required for bike share fleet rebalancing and maintenance. These two components are then combined to estimate bike share’s overall contribution to changes in vehicle kilometers traveled. The results indicate an estimated reduction in motor vehicle use due to bike share of approx. 90,000 km per annum in Melbourne and Minneapolis/St. Paul and 243,291 km for Washington, D.C. London’s bike share program however recorded an additional 766,341 km in motor vehicle use. This was largely due to a low car mode substitution rate and substantial truck use for rebalancing of bicycles. As bike share programs mature, evaluation of their effectiveness in reducing car use may become increasingly important. Researchers can adapt the analytical approach proposed in this paper to assist in the evaluation of current and future bike share programs.
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This paper introduces an integral approach to the study of plasma-surface interactions during the catalytic growth of selected nanostructures (NSs). This approach involves basic understanding of the plasma-specific effects in NS nucleation and growth, theoretical modelling, numerical simulations, plasma diagnostics, and surface microanalysis. Using an example of plasma-assisted growth of surface-supported single-walled carbon nanotubes, we discuss how the combination of these techniques may help improve the outcomes of the growth process. A specific focus here is on the effects of nanoscale plasma-surface interactions on the NS growth and how the available techniques may be used, both in situ and ex situ to optimize the growth process and structural parameters of NSs.
Resumo:
Filling the need for a single work specifically addressing how to use plasma for the fabrication of nanoscale structures, this book is the first to cover plasma deposition in sufficient depth. The author has worked with numerous R&D institutions around the world, and here he begins with an introductory overview of plasma processing at micro- and nanoscales, as well as the current problems and challenges, before going on to address surface preparation, generation and diagnostics, transport and the manipulation of nano units.