952 resultados para TRANSPORT SYSTEMS


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Hybrid powerplants combining internal combustion engines and electric motor prime movers have been extensively developed for land- and marine-based transport systems. The use of such powerplants in airborne applications has been historically impractical due to energy and power density constraints. Improvements in battery and electric motor technology make aircraft hybrid powerplants feasible. This paper presents a technique for determining the feasibility and mechanical effectiveness of powerplant hybridisation. In this work, a prototype aircraft hybrid powerplant was designed, constructed and tested. It is shown that an additional 35% power can be supplied from the hybrid system with an overall weight penalty of 5%, for a given unmanned aerial system. A flight dynamic model was developed using the AeroSim Blockset in MATLAB Simulink. The results have shown that climb rates can be improved by 56% and endurance increased by 13% when using the hybrid powerplant concept.

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Improving safety at railway level crossings is an important issue for the Australian transport system. Governments, the rail industry and road organisations have tried a variety of countermeasures for many years to improve railway level crossing safety. New types of Intelligent Transport System (ITS) interventions are now emerging due to the availability and the affordability of technology. These interventions target both actively and passively protected railway level crossings and attempt to address drivers’ errors at railway crossings, which are mainly a failure to detect the crossing or the train and misjudgement of the train approach speed and distance. This study aims to assess the effectiveness of three emerging ITS that the rail industry considers implementing in Australia: a visual in-vehicle ITS, an audio in-vehicle ITS, as well as an on-road flashing beacons intervention. The evaluation was conducted on an advanced driving simulator with 20 participants per trialled technology, each participant driving once without any technology and once with one of the ITS interventions. Every participant drove through a range of active and passive crossings with and without trains approaching. Their speed approach of the crossing, head movements and stopping compliance were measured. Results showed that driver behaviour was changed with the three ITS interventions at passive crossings, while limited effects were found at active crossings, even with reduced visibility. The on-road intervention trialled was unsuccessful in improving driver behaviour; the audio and visual ITS improved driver behaviour when a train was approaching. A trend toward worsening driver behaviour with the visual ITS was observed when no trains were approaching. This trend was not observed for the audio ITS intervention, which appears to be the ITS intervention with the highest potential for improving safety at passive crossings.

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Description of a simple method for counting bacteria with active electron transport systems in water and sediment samples. Sodium succinate, NADH and NADPH served as electron donors. It is possible to see several sites of electron transport in the larger cells. Especially impressive are the plankton-algae, protozoa, and small metazoa. This is a partial translation of the ”method” section only.

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In S. cerevisiae lacking SHR3, amino acid permeases specifically accumulate in membranes of the endoplasmic reticulum (ER) and fail to be transported to the plasma membrane. We examined the requirements of transport of the permeases from the ER to the Golgi in vitro. Addition of soluble COPII components (Sec23/24p, Sec13/31p, and Sar1p) to yeast membrane preparations generated vesicles containing the general amino acid permease. Gap1p, and the histidine permease, Hip1p. Shr3p was required for the packaging of Gap1p and Hip1p but was not itself incorporated into transport vesicles. In contrast, the packaging of the plasma membrane ATPase, Pma1p, and the soluble yeast pheromone precursor, glycosylated pro alpha factor, was independent of Shr3p. In addition, we show that integral membrane and soluble cargo colocalize in transport vesicles, indicating that different types of cargo are not segregated at an early step in secretion. Our data suggest that specific ancillary proteins in the ER membrane recruit subsets of integral membrane protein cargo into COPII transport vesicles.

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Urban mobility is one of the main challenges facing urban areas due to the growing population and to traffic congestion, resulting in environmental pressures. The pathway to urban sustainable mobility involves strengthening of intermodal mobility. The integrated use of different transport modes is getting more and more important and intermodality has been mentioned as a way for public transport compete with private cars. The aim of the current dissertation is to define a set of strategies to improve urban mobility in Lisbon and by consequence reduce the environmental impacts of transports. In order to do that several intermodal practices over Europe were analysed and the transport systems of Brussels and Lisbon were studied and compared, giving special attention to intermodal systems. In the case study was gathered data from both cities in the field, by using and observing the different transport modes, and two surveys were done to the cities users. As concluded by the study, Brussels and Lisbon present significant differences. In Brussels the measures to promote intermodality are evident, while in Lisbon a lot still needs to be done. It also made clear the necessity for improvements in Lisbon’s public transports to a more intermodal passenger transport system, through integration of different transport modes and better information and ticketing system. Some of the points requiring developments are: interchanges’ waiting areas; integration of bicycle in public transport; information about correspondences with other transport modes; real-time information to passengers pre-trip and on-trip, especially in buses and trams. After the identification of the best practices in Brussels and the weaknesses in Lisbon the possibility of applying some of the practices in Brussels to Lisbon was evaluated. Brussels demonstrated to be a good example of intermodality and for that reason some of the recommendations to improve intermodal mobility in Lisbon can follow the practices in place in Brussels.

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The lung possesses specific transport systems that intra- and extracellularly maintain salt and fluid balance necessary for its function. At birth, the lungs rapidly transform into a fluid (Na(+))-absorbing organ to enable efficient gas exchange. Alveolar fluid clearance, which mainly depends on sodium transport in alveolar epithelial cells, is an important mechanism by which excess water in the alveoli is reabsorbed during the resolution of pulmonary edema. In this review, we will focus and summarize on the role of ENaC in alveolar lung liquid clearance and discuss recent data from mouse models with altered activity of epithelial sodium channel function in the lung, and more specifically in alveolar fluid clearance. Recent data studying mice with hyperactivity of ENaC or mice with reduced ENaC activity clearly illustrate the impaired lung fluid clearance in these adult mice. Further understanding of the physiological role of ENaC and its regulatory proteins implicated in salt and water balance in the alveolar cells may therefore help to develop new therapeutic strategies to improve gas exchange in pulmonary edema.

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The rapid deployment of intelligent transport systems in practice requires serious evaluation of new construction projects. Traditional transportation evaluation methods are insufficient to capture the new features of intelligent transport systems, particularly the applications of recently developed information technologies. This research aims to develop a new conceptual framework to evaluate the social, economic and environmental impacts of intelligent transport systems deployment, with explicit consideration of impacts of information technologies on variant travel behaviours. The research would provide a systematic evaluation methodology to enable decision makers and publics better evaluating and understanding the social, economic and environmental benefits of implementation of intelligent transport systems.

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Many aspects of our modern society now have either a direct or implicit dependence upon information technology. As such, a compromise of the availability or integrity in relation to these systems (which may encompass such diverse domains as banking, government, health care, and law enforcement) could have dramatic consequences from a societal perspective. These key systems are often referred to as critical infrastructure. Critical infrastructure can consist of corporate information systems or systems that control key industrial processes; these specific systems are referred to as ICS (Industry Control Systems) systems. ICS systems have devolved since the 1960s from standalone systems to networked architectures that communicate across large distances, utilise wireless network and can be controlled via the Internet. ICS systems form part of many countries’ key critical infrastructure, including Australia. They are used to remotely monitor and control the delivery of essential services and products, such as electricity, gas, water, waste treatment and transport systems. The need for security measures within these systems was not anticipated in the early development stages as they were designed to be closed systems and not open systems to be accessible via the Internet. We are also seeing these ICS and their supporting systems being integrated into organisational corporate systems.

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Congestion pricing schemes have been implemented in cities worldwide as a means of addressing externalities associated with inefficient price signals in transport systems. Limited evidence exists however on the secondary impacts of these schemes, which may include both environmental and health benefits associated with a resultant reduction in motor vehicle usage. There is increasing recognition that transport behaviours may play a role as opportunistic population level targets to reduce physical inactivity. Yet limited evidence currently exists on the effectiveness of transport interventions, such as congestion pricing schemes, for improving physical activity levels.This study aims to examine the physical activity effects of congestion pricing, with the health benefits of physical activity well established. Congestion pricing schemes implemented internationally were considered as 'natural experiments' and evidence of modal shift from vehicle to active forms of transport or physical activity effect was reviewed. Twelve studies were included from a search of peer-reviewed and 'grey' literature, with overall evidence for a physical activity or modal shift effect considered weak. The quality of the available evidence was also considered to be low.This is not to say that congestion pricing schemes may not have important secondary physical activity related health benefits. Instead, this review highlights the paucity of evidence that has been collected from real-world implementation of congestion pricing schemes. Given the growing recognition of the importance of distal mediators and determinants of health and the need for an 'all-of-government' approach more and better quality evidence of effectiveness of transport interventions for a broad range of outcomes, including health, is required. Significant barriers to the collection of such evidence exist, with strategies for overcoming some of these barriers identified. Only with a better understanding of the full range of potential health impacts can transport policy be fully utilised as a tool for population health.

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Over the past three years, talks conducted at the subregional level have led to the signing of multimodal transport agreements, and these have been implemented by Mercosur and reviewed by the Andean Community; multimodal transport is only now starting to come into its own in South America but is already a common practice in the region covered by NAFTA. These trends continued in 1997, with consolidation being the dominant theme; on the one hand, consolidation occurred in business, with integrated services increasingly on offer, while on the other the authorities became aware of the need to promote linkages between different modes of transport. Highlights of 1998 may well include major plans for investments in intermodal infrastructure and greater interaction between users and service providers in both the public and private sectors, in order to develop regional intermodal transport systems.

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The process of urbanization in Latin America presents new challenges for urban transport systems insofar as one of the priorities is to provide proper mobility for the increasing and complex interaction of communities.This edition of the Bulletin, prepared by Irma Chaparro, presents a summary of the recent study entitled Evaluación del impacto socio-económico del transporte urbano en la ciudad de Bogotá. El caso del sistema masivo de transporte, Transmilenio, LC/L 1786-P, October 2002, which considers the socioeconomic impact of the Transmilenio system in Bogotá. This system is part of an integrated transport strategy promoted by the District Authority over the period 1998-2001 and is an avant-garde solution to the difficult problem of transport in the city.

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Since the birth of the European Union on 1957, the development of a single market through the integration of national freight transport networks has been one of the most important points in the European Union agenda. Increasingly congested motorways, rising oil prices and concerns about environment and climate change require the optimization of transport systems and transport processes. The best solution should be the intermodal transport, in which the most efficient transport options are used for the different legs of transport. This thesis examines the problem of defining innovative strategies and procedures for the sustainable development of intermodal freight transport in Europe. In particular, the role of maritime transport and railway transport in the intermodal chain are examined in depth, as these modes are recognized to be environmentally friendly and energy efficient. Maritime transport is the only mode that has kept pace with the fast growth in road transport, but it is necessary to promote the full exploitation of it by involving short sea shipping as an integrated service in the intermodal door-to-door supply chain and by improving port accessibility. The role of Motorways of the Sea services as part of the Trans-European Transport Network is is taken into account: a picture of the European policy and a state of the art of the Italian Motorways of the Sea system are reported. Afterwards, the focus shifts from line to node problems: the role of intermodal railway terminals in the transport chain is discussed. In particular, the last mile process is taken into account, as it is crucial in order to exploit the full capacity of an intermodal terminal. The difference between the present last mile planning models of Bologna Interporto and Verona Quadrante Europa is described and discussed. Finally, a new approach to railway intermodal terminal planning and management is introduced, by describing the case of "Terminal Gate" at Verona Quadrante Europa. Some proposals to favour the integrate management of "Terminal Gate" and the allocation of its capacity are drawn up.