bluuebunny/crossref_metadata_2025 huggingface dataset:
Modelling rail track performance: an integrated approach
Authors: Zhang Y.-J. , Murray M. , Ferreira L.
Published: November 2009

Ongoing work at the Queensland University of Technology has developed an integrated computer-based tool for the prediction of rail track behaviour under changing traffic conditions. The track degradation model described in this paper takes into account degradation due to interactions between track components. The model uses mechanistic relationships and embraces all the major factors that may influence service life of track components. The model was applied to a typical Australian railway track. The results showed that increasing axle load and train speed accelerates degradation of the track and wear of rails. The rate of failure of timber sleepers is sensitive to the age of the sleepers, traffic parameters and to environmental factors such as rate of decay of timber and how well the track drains. Increases in axle loads may not lead to a higher rate of sleeper damage failure at fixed traffic tonnage.
Geotechnical investigation and assessment of potential building damage arising from ground movements: CrossRail
Authors: Torp-Petersen G. E. , Black M. G.
Published: November 2009

One of the largest geotechnical survey and site investigations ever carried out in London, costing approximately £3 million, was undertaken prior to the design of the underground sections of CrossRail. This paper outlines the procurement, management and technical aspects of this survey, the application of the results to the prediction of ground movements arising from tunnelling and the design of building protective works.
CrossRail: External influences and the way forward
Authors: Heath D. L.
Published: November 2009

The first six papers have described many of the technical aspects of CrossRail, from the early feasibility work to the detailed design. The final paper, after outlining the conclusion of the Private Bill process and CrossRail's current status within the Government's Transport Strategy, deals with the political scene within which the technical work was undertaken, including many of the lessons learnt. Finally, possible ways of taking CrossRail forward as a Private Finance Initiative project are suggested.
Metrolink—building on success
Authors: Tyson W. J.
Published: November 2009

The paper begins by giving the background to the successful Metrolink light rail system in Greater Manchester. It then analyses the reasons for this success which stem from the fact that it has been able to offer passengers a faster and higher-quality journey than both the car and bus. This success as a transport system has led to both social and economic benefits for the community as a whole, including the reduction of road traffic. Next, the development of the plans for the expansion of the network are examined, showing how the factors which have led to the success of the first phase have been built into the plans for future lines. The paper concludes by looking at three specific aspects which are crucial to the delivery of an expanded system: the implications of the Transport and Works Act, procurement and funding, and the development of integrated transport networks under the Government's transport policies.
Vulnerability analysis of highway networks, methodology and case study
Authors: Lleras-Echeverri G. , Sánchez-Silva M.
Published: November 2009

Current methods to assess the vulnerability of highway networks concentrate on the evaluation of individual infrastructure elements such as bridges or tunnels. Only a few methodologies have been proposed to study the effects of the failure of a set of links on a network as a whole. A method that analyses the consequences of the failure of each link comprising a network from an operational point of view is proposed in this paper. The procedure proposes an efficient strategy for modelling and managing transportation networks. The results are used to identify critical links in the network for allocating maintenance and rehabilitation resources. In addition, resources for detailed planning of hazard studies can be optimised based on the results of the methodology. It follows a systems approach and uses transportation modelling techniques. A critical scenario-based approach is proposed for optimising the analysis. This paper proposes a methodology considering these factors and presents a case study applied to a section of the Colombian highway network.
Channel Tunnel Rail Link—high speed, low impact, minimum cost
Authors: Allett E. J. , Greer R. J. , Manning C.
Published: November 2009

The Channel Tunnel Rail Link (CTRL) is a new high-speed rail link between the Channel Tunnel and London. In planning any transportation corridor, what people will see and hear is always at the forefront of residents’ and local authorities’ concerns. Noise mitigation is therefore a major issue that has to be resolved to obtain planning approval for a scheme. Noise issues can often be ‘bought off’ with the provision of more mitigation. However, uncontrolled this can severely affect the economics of a scheme. Union Railways, supported by Rail Link Engineering and its ‘home’ companies (Arup, Bechtel, Halcrow and SYSTRA), has tackled this difficult balance and has, through innovative integrated design and management, won the support of local authorities to deliver high environmental performance at reasonable cost. The paper outlines the methods employed on Section 1 of the Project.
Barrier designs to reduce road traffic noise
Authors: Watts G.
Published: November 2009

Traffic noise reduction is an important area of public concern since nearly ten per cent of the population are seriously bothered by this type of noise. The reduction of noise annoyance can be tackled at any stage from generation at the source to the perception by the listener. Three stages can be identified: generation, propagation and reception. Mitigation measures fall into all three categories and an overview of relevant research into reducing sound propagation using roadside barriers is described in this paper. It should be borne in mind that to obtain a significant reduction in noise it may sometimes be necessary to effect a reduction at two or more stages. This is a ‘combined mitigation’ approach; for example, the use of low noise surfaces with noise barriers. Cost-effectiveness is also very important especially when public funds are involved. Additionally, public acceptability needs to be considered since a mitigation may be highly effective in reducing noise but not appropriate; for example, a visually intrusive noise barrier. Underpinning the research carried out by TRL have been significant advances in mathematical modelling that have allowed complex situations to be modelled accurately. This has involved the use of Boundary Element Methods (BEM) and a key requirement has been the need to validate the results as the method has developed. A noise barrier test facility at TRL has allowed a wide variety of barrier shapes to be tested at full scale to measure values for comparison with model predictions. Agreement has been good which has given confidence in the modelling approach adopted.
Controlling noise by wheel and track design
Authors: Thompson D. J. , Jones C. J. C.
Published: November 2009

Rolling noise forms the main source of noise from railways. Effective control at source requires a good understanding of the mechanisms of generation. To this end, detailed theoretical models for rolling noise have been developed. Using these methods, it is possible to evaluate the rolling noise behaviour of different wheel and track designs, allowing new designs to be derived that are inherently quieter. In this paper, an overview is given of the mechanisms involved in noise generation and the parameters that have most influence are identified. Examples are then given of two techniques that have been developed using the model with the aim of reducing the noise at source. A tuned absorber system applied to the rail is found in field measurements to reduce the noise from the track by about 6 dB(A). The wheel component of noise can be reduced by an optimised wheel shape in combination with damping treatments.
A new approach for the accelerated ageing of porous asphalt mixtures
Authors: Khalid H. A.
Published: November 2009

Age hardening is related to progressive oxidation of all bituminous bound layers in flexible pavements. Excessive age hardening is of particular relevance to surface courses where it can cause premature breakdown; it is of major importance to engineers and scientists involved in the design, construction and maintenance of such pavements. This paper discusses the development of a new method for the accelerated ageing of bituminous mixtures, based on the use of a forced draft approach, to reproduce field-ageing effects in the laboratory. The applicability of the method to ageing of porous asphalt mixtures is investigated using four bitumens: a 100 pen conventional and three polymer modified binders, including Styrene Butadiene Styrene (SBS) and Ethylene Vinyl Acetate (EVA) copolymers. The new method is shown to be capable of ranking the mixtures in a reasonable order, emphasising the improved properties of polymer modified mixtures. A useful correlation has been established between the ageing resistance of mixtures and that of their recovered binders. Stiffness moduli evaluated in the Nottingham asphalt tester were used to characterise the unaged and aged mixtures, whereas the binders were characterised through their rheological properties measured in the dynamic shear rheometer. Mixture ageing results obtained from the developed laboratory method were compared with those of samples exposed to environmental ageing conditions sustained on a building rooftop for 18 months.
Visco-elastoplastic method for pavement performance evaluation
Authors: Lu Y. , Lu L. , Wright P. J.
Published: November 2009

This paper describes the principle of visco-elastoplastic analysis and its applications to the performance analyses of pavement structures. In this method, strains are categorised into three groups as elastic, viscoelastic and viscoplastic components, according to whether they are time-dependent and recoverable during the unloading period. The visco-elastoplastic method has been implemented in a finite element program and applied to the study of the mechanical behaviour of a three-layer road structure to simulate the development of pavement rutting. Computational results show that performance of a typical pavement is greatly influenced by pavement temperatures and thickness of the asphalt layer. The elastic modulus of the base is also an important parameter in the evaluation, but response of the asphalt layer to the changes of base thickness and strength is not very significant. It is also found that in a typical pavement structure the viscous response of the subgrade to the structural and temperature changes of the pavement system may not be as strong as that of the asphalt layer.
Binder influence type on deformation resistance of stone mastic asphalt
Authors: Lum K. M. , Hassabo N. I.
Published: November 2009

Rutting reduces the service life of an asphalt pavement because it can lead to structural failure. Stone Mastic Asphalt (SMA) has a number of properties providing better quality than the generic types of asphalt mixtures. However, SMA is generally laid as a bituminous surfacing layer to counter problems associated with permanent deformation and durability of an asphalt pavement. This paper compares the rutting resistance and resilient modulus of SMA batched with polymer-modified and process-modified binders to those SMA batched with PEN 60/70 conventional bitumen. Ten slabs were successfully fabricated and roll-compacted to obtain rut and resilient modulus specimens. A total of 20 rectangular sawed specimens were tested for rutting resistance, while 30 cylindrical core specimens were tested for resilient modulus. The findings indicated that both the polymer-modified and process-modified binders would enhance the rutting resistance of SMA. Better compacted specimens would improve the rutting resistance of SMA. An in-depth analysis using general linear modelling indicated that the polymer-modified and process-modified binders, compaction level, and temperature and pulse width had a major impact on the resilient modulus of SMA. Lastly, it may be generally concluded that the higher the resilient modulus, the higher will be the rutting resistance to permanent deformation.
A new technique for using multivariate adaptive regression splines (MARS) in pavement roughness prediction
Authors: Attoh-Okine N. O. , Mensah S. , Nawaiseh M.
Published: November 2009

The paper presents the application of a new statistical technique, multivariate adaptive regression splines (MARS), to a flexible pavement roughness prediction model. MARS is a non-parametric function estimation technique that shows great promise for fitting non-linear multivariate functions. The MARS approach was used to develop a roughness equation, based on available input, and was able to identify the threshold values of each input and the most important variables contributing to the roughness equation. The MARS technique allows easy interpretation of the relative importance of pavement condition variables, environmental factors and traffic for the overall fit.
Influence of layer bonding on the prediction of pavement life
Authors: Khweir K. , Fordyce D.
Published: November 2009

It is important to recognise that pavement performance can be seriously compromised by interface problems, even though the performance of an individual layer may be very high. This means that pavements may fail with traffic volumes far less than the design values in spite of the fact that individual layers may exhibit reasonably high dynamic stiffness modulus values, high permanent deformation resistance and high fatigue properties. Material properties and some construction practices can create weak or no interface bonding. Bond failure at one interface can cause a predicted loss of two-fifths to five-sixths, to as low as one sixth of the potential life of the pavement. Pavement analysis based on the assumption that all bound layers work as one single layer is seriously misleading if the bond at one or more layer interfaces is weak or has failed. The fatigue property of a pavement layer above an interface is very sensitive to variations in layer dynamic stiffness modulus, layer thickness and the degree of lateral movement available at the interface.
Dynamic mechanical testing of bitumen: sample preparation methods
Authors: Airey G. D. , Hunter A. E.
Published: November 2009

The dynamic shear rheometer (DSR) is one of the most complex and powerful instruments currently used to characterise the flow properties of bitumen. With the increased rheological characterisation of bitumens, particularly polymer-modified bitumens, by means of these dynamic mechanical methods, there is now an urgent need to standardise DSR testing procedures to ensure the repeatability and reproducibility of the rheological data. This paper describes an investigation of the influence of three sample preparation methods (hot pour, silicone mould and weighing) on the magnitude and repeatability of rheological parameters measured during DSR testing. The effect of the different sample preparation methods has been evaluated for a penetration grade and polymer-modified bitumen using a controlled-stress rheometer. The results indicate that a method involving the pouring of hot bitumen onto one of the plates of the DSR and then trimming the edge of the sample is the most consistent means of sample preparation. In addition, the magnitude of the measured rheological parameters is influenced by the sample preparation method, with the silicone mould and weighing methods producing consistently higher and lower values of complex modulus respectively than the hot-pour method.
Tests on a two-layered ballast system
Authors: Claisse P. , Keedwell M. , Calla C.
Published: November 2009

Considerable evidence suggests that ballast is the main cause of uniform and non-uniform settlement of railway track, provided the subgrade is adequately specified. Over a period of time uneven settlement of the ballast will cause voids to form under the sleepers, leading to unacceptable ride quality of the track. Regular maintenance is required to keep the track geometry within acceptable limits and to maintain ride quality. The proposed two-layered ballast system described in this paper would replace the crib ballast by stone of smaller size. The aim is to fill the voids beneath the sleepers as soon as they become unacceptably large and thus to maintain ride quality without the use of tamping or stone-blowing. Preliminary model tests carried out on the system indicate good potential for it. The results of the model tests have been validated by full-scale tests in the laboratory. The tests have shown that by replacing crib ballast by stone of smaller size a void beneath the sleeper will be filled up to less than the void size minus the average particle size of crib ballast. The next logical step is to go for full-scale live track trials, and it is anticipated that these will take place in the near future.
Which technology for urban public transport?
Authors: Brand C. , Preston J.
Published: November 2009

The merits of alternative urban and inter-urban public transport systems have been the subject of some debate, particularly since the publication of the UK's 1998 transport policy White Paper A New Deal for Transport. This current paper aims to assess some of the conflicting empirical evidence in the UK and abroad in order to allow an objective assessment of the policy implications. Section 2 presents an overview of technical and financial characteristics of mainly urban public transport systems, including capital and operating costs of recent light rail, guided bus, bus priority and suburban rail systems. Section 3 explores the evidence on the wider costs and benefits of systems in the UK, including wider environmental and socio-economic impacts. Although more expensive to build (under similar conditions), light rail systems often carry more passengers than ‘intermediate’ bus-based systems such as guided bus and segregated busways. There is not much between public transport systems on the basis of operating costs per passenger-km, except metro systems, which are twice as expensive to run as bus-based systems. When comparing revenues and operating costs directly, all modes except suburban regional rail appear capable of covering operating costs overall, with light rail and some of London's suburban rail services providing a marginal surplus of revenue. Average speeds of light rail and bus-based systems are comparable. In heavily congested corridors, new light rail systems can reduce journey times significantly, but such reductions are lower for bus-based systems, mainly because of the relatively limited amount of segregated right of way and priority at traffic signals. This highlights the fact that bus priority systems act primarily as ‘congestion busters’ at hot spots, which can be implemented more flexibly and gradually than for rail-based systems. Currently, electric propulsion appears to be the best option to mitigate air pollution and noise. However, new clean vehicle technologies will soon be in a position to play a major role in reducing emissions, in particular for bus-based systems. In terms of external costs per bus/train-km, environmental costs appear higher than accident costs, but lower than congestion externalities.
An investigation of lane utilisation on Turkish highways
Authors: Gunay B.
Published: November 2009

This paper, being the first report on ‘lane utilisation on Turkish highways’, explores some of the unconventional characteristics of multilane traffic flows. As in many developing countries, the discipline of lane-based driving in Turkey is fairly weak. Possible reasons for this problem are different driving attitudes, poor road surface, poorly maintained lane markings, and the non-existence of studs on lane lines. The possible consequences of the problem, thus, could be loss of safety, difficult traffic management, inapplicability of conventional lane-based models, etc. Findings revealed that lateral positions of vehicles within the lane were more disorderly when compared with developed countries, where a normal distribution can be used. Regarding the distribution of vehicles over the lanes, the results in general were significantly different from the existing diagrams of some European highways. The proportion of traffic exhibited totally opposite trends for the median and shoulder lanes in Turkey, especially with wider shoulders. Whereas using the shoulder provided some extra capacity, along with some disadvantages, highways with no shoulders discharged less traffic than their counterparts from the developed world. Therefore, the present paper is thought to be the first step of the research into the problem of untidiness.
Evaluation of a national congestion charging system
Authors: Copley G. , Dodgson J.
Published: November 2009

In work undertaken for the Commission for Integrated Transport, the authors have demonstrated that a national road user charging system could be developed that would make more efficient use of road space. The system could, in principle, charge motorists on a distance basis for every part of the road system, with charges varying by time of day and level of congestion, avoiding the issue of diversion of traffic onto unsuitable roads that would arise if charges only applied to the motorway system. This ‘peak-pricing’ mirrors the way we pay for other utilities such as telephone and electricity. The system could be ‘revenue-neutral’ such that the funds raised through the charges are balanced by reductions in vehicle excise duty and/or fuel tax. Alternatively, subject to Treasury agreement, variants could hypothecate some of the funding to transport improvements. The system could bring benefits to a large number of low-mileage drivers and rural residents who depend on their cars but impose little on others because they tend to drive in non-congested conditions. It would encourage drivers in congested conditions to reconsider whether their journey is necessary, whether it could be made by another mode or at a less congested time of day. The paper describes the findings from the research work, highlighting the technical, political and practical issues, and providing further insights into the impacts of such a scheme.
Applying commercial advertising skills in transport planning
Authors: Wiltshire P. J.
Published: November 2009

The motor car has become more than a means of transport. Despite the high cost and dire road safety problems, the car has become a totem in our social grouping and a metaphor for our lifestyle aspirations. This did not happen by accident. It is the consequence of some 90 years of soft-selling and highly sophisticated marketing. This paper explores the techniques that the advertising profession uses, and touches upon their application in marketing sustainable transport modes.
Travel time constraints in transport policy
Authors: Metz D.
Published: November 2009

Average travel time per person has remained constant at about an hour a day for at least the past 30 years, over which period average distance travelled has increased by over 50%. The average number of trips per person has also held steady, at 1000 per year. It follows that the growth in travel has taken the form of longer journeys at higher average speeds. Most of the intended investment in the UK Government's Ten Year Transport Plan has the effect of increasing average speed. This will increase distances travelled within constant average travel time, will result in increased environmental detriments, and is not likely to have a perceptible impact on congestion. Congestion charging could reduce distances travelled, but raises an issue of equity. Some approaches are discussed that could increase transport system efficiency without increasing average speed.
Madrid–Valencia high-speed rail line: a route selection
Authors: Anton J. M. , Grau J. B.
Published: November 2009

This paper presents the application of the multicriteria decision-making methods ELECTRE-I and AHP to a layout alternatives decision for a new high-speed train for the Madrid–Valencia high-speed line. The official choice is presented as a first introduction with the planning decision of the corresponding new high-speed lines for the south-east of Spain as part of the 2002–2007 high-speed network plan for Spain. This official selection of layout alternatives was decided in January 2002. The data used by the authors were obtained from public reports and official surveys, including two cost-effectiveness studies in net present value format for that part of the network that includes the important link between Madrid and Valencia. A short analysis of these net present value studies follows, and these studies show the feasibility of that part of the network, but were not decisive for the decision of the layout choice. The selection of alternatives for the Madrid–Valencia corridor is academically considered first with an ELECTRE-I method, and then with an analytic hierarchic process method. This is followed by an analysis of the problems using compromise programming. With both multicriteria decision-making methods the results showed that the North option was preferable, or ‘outranked’ the others, in agreement with the official selection. Thus it demonstrates that such methods are appropriate as aids for such decision-making procedures.
Development of the saturation ageing tensile stiffness (SATS) test
Authors: Collop A. C. , Choi Y. K. , Airey G. D. , Elliott R. C.
Published: November 2009

This paper describes the development of a combined ageing/moisture sensitivity laboratory test to evaluate the performance of coated macadam binder course and base mixtures with relatively low binder contents and relatively high air void contents. The test is known as the saturation ageing tensile stiffness (SATS) test, and consists of initial saturation prior to placing compacted asphalt core samples in a high-temperature and high-pressure environment in the presence of moisture for an extended period of time. The stiffness modulus measured after the test divided by the stiffness modulus measured before the test (retained stiffness modulus), and the specimen saturation after the test (retained saturation), are used as an indication of the sensitivity of the compacted mixture to combined ageing/moisture effects. The test was used to reproduce in the laboratory the loss of stiffness modulus observed on a trial site where high modulus base (HMB) had been used. Two different aggregate types (basic and acidic) and four different binders were used in the HMB mixture that was investigated. For the mixtures containing the acidic aggregate, the general trend is for the retained stiffness modulus to reduce from approximately 0·6 at a retained saturation level of 10% to 0·2 at a retained saturation level of between 80% and 100%. At a retained saturation level of 40% the retained stiffness modulus is approximately 0·4, which compares favourably with the 60% reduction in stiffness modulus observed from the HMB trial site (for nominally identical mixtures). For the mixtures containing the basic aggregate, the retained stiffness modulus remains at an approximately constant value of 0·7 over a wide range of retained saturation levels (between 15% and 80%), indicating a lower sensitivity to moisture. For the low binder content, high air void content mixtures investigated, the effect of changing the binder (source and grade) was small compared with the effect of the aggregate type.
Motorway incident detection using probe vehicles
Authors: Li Y. , McDonald M.
Published: November 2009

Vehicles that collect data from a traffic stream of which they are part (i.e. probe vehicles) have been shown to provide reliable and cost-effective real-time travel information. This paper presents a probe-vehicle-based algorithm designed to detect incidents on motorways. The algorithm is based on a bivariate analysis model (BEAM) using two variables: the average travel times of probe vehicles, and the travel time differences between adjacent time intervals. The premise of the model is that link travel times increase more rapidly as a result of a change in capacity (i.e. when an incident occurs) than as a result of a change in demand. The statistical principles of bivariate analysis have been used to study the relationships between the two variables in incident and non-incident conditions. Four motorway road links with field data have been used to test the feasibility of the model with 99% and 99·9% coverage contours respectively. The model achieved an average incident detection rate of 89·5% with a false alarm rate of 0·71% using the 99% coverage contour. The average incident detection rate was 73·7% with a false alarm rate of 0·57% using the 99·9% coverage contour.
Extent of capacity loss resulting from pavement distress
Authors: Ben-Edigbe J. , Ferguson N.
Published: November 2009

The subject of this paper is the extent of pavement distress impact on traffic capacity of uninterrupted road link sections. A capacity estimation method based on extrapolation from a fundamental diagram representing the relationship between traffic flow and density was used. This method assumes that density is a result of speed and flow on sections of the road link at capacity, and hence is not directly affected by road surface distress. This implies that the capacity shifts are entirely the result of speed changes. In a ‘without and with’ distress study at selected sites in Nigeria, the impact of road surface distress was estimated for one direction of the road link section. Capacities of the road section were estimated for three sections (‘without distress’, ‘transition’ and ‘with distress’) of the road link and it was found that capacities on ‘without distress’ and ‘with distress’ sections differed significantly. The paper concludes that a significant decrease in capacity of about 30% was found, and is attributable to road pavement distress.
Thermal buckling of pavement slabs
Authors: Croll J. G. A.
Published: November 2009

A continuous pavement slab subject to an increase in temperature will experience compressive stress which, if sufficiently large, can cause an uplift buckling failure. In contrast with the more familiar and relatively simple buckling of columns, this thermal uplift buckling of pavement slabs will generally occur with little warning, possibly with considerable violence, and at temperatures that have the undesirable feature of being very sensitive to the precise forms and magnitudes of any small initial out-of-flatness of the slab. This paper discusses the mechanics involved in the uplift buckling of slabs and describes the analysis for buckling as two separate modes. The first mode is similar to that which could be experienced in a one-dimensional beam and controls the thermal buckling of components such as railway lines, sub-sea pipelines and one-dimensional road pavements. This allows the second mode in the form of a dimple deformation for two-dimensional pavements to be clearly placed into the context of previous work in this field. Parameter studies show that this relatively neglected form of pavement failure could help to explain certain forms of previously experienced pavement breakup, and could provide important design constraints on future pavement design.
Effects of surface cracking on responses in flexible pavements
Authors: Mohammad F. A. , Collop A. C. , Brown S. F.
Published: November 2009

This paper investigates the effects of surface cracks on the primary responses to wheel loading in a model of a flexible pavement structure. Details of the modelling procedure using finite-element analysis are presented and the effects of different material properties and crack lengths are reported. Results show that in an uncracked flexible pavement structure, the inclusion of horizontal tractions imposed by the wheel load results in narrow regions of horizontal tensile strain at the pavement surface and a high shear strain at the edge of the tyre which could lead to crack initiation. The presence of a surface crack results in a localised region of high horizontal tensile stress and strain at the edge of the tyre, making further crack propagation possible. The predicted horizontal tensile strains increase as the stiffness modulus of the asphalt layer is decreased. The presence of a surface crack results in a high value of shear strain at the crack tip, which increases as the stiffness modulus of the asphalt layer is decreased. The predicted horizontal tensile strain at the base of the asphalt layer is not sensitive to a surface crack until it reaches approximately 50 mm (25% of the layer thickness), after which it increases. The predicted shear strain at the crack tip increases linearly with increasing crack length.
Development of a vehicle emissions monitoring system
Authors: North R. J. , Ochieng W. Y. , Quddus M. A. , Noland R. B. , Polak J. W.
Published: November 2009

Investigation of vehicle emissions with an on-board emissions measurement system can provide a better understanding of how these emissions contribute to air pollution. This paper discusses the design and development by Imperial College London and industrial collaborators of a vehicle performance and emissions monitoring system, including its installation both on test vehicles allowing an interface with the engine management system and those that do not. Results from preliminary field trials and chassis dynamometer testing of the diesel test vehicle are presented. Good correlation between the monitoring system and reference measurements is observed, with differences in aggregate measurements of between 8% and 18% over a standard test cycle. The remote download and synthesis of navigation, performance and emissions data from an in-use vehicle was successfully achieved. This project has shown that it is possible to produce a system suitable for deployment for simultaneous studies over a wide area. However, the non-standard nature of engine management system interfaces for much of the European vehicle fleet presents a significant barrier to implementation. It is therefore recommended that European legislation be enforced to ensure standard interfaces on all new vehicles.
Developing a road traffic control system with GIS
Authors: Yang Z. Z. , Jiang Y. L. , Chen Y.
Published: November 2009

Since the onset of rapid urbanisation and the growth in vehicular transport in China, the cycle time for supplying urban road demand has become shorter, requiring urban road traffic control information such as signal controls, traffic marks and signs to change dramatically. This has led to a much greater focus on how to collect, manage and update dynamic traffic control information and to analyse traffic resources with this information. The present study aimed to develop a system to manage road traffic control information and analyse traffic resources using visual techniques. In this system road traffic control information is represented as objects such as points, lines or regions in a geographic information system (GIS) and their specifications are stored in an attribute table of the objects. Moreover, graphic user interfaces were developed to process, edit, query, display and print the information. A road traffic resource analysis system has been developed based on the road network and the relevant traffic control information. This system has been implemented by the city police and is being used by the urban traffic police to manage and disseminate the information.
Accommodating household growth in Britain
Authors: Cowans J.
Published: November 2009

A recent study explored some of the inherent difficulties in combining and coordinating a number of strategies to facilitate economic and physical growth across disciplines. By examining these issues in north Northamptonshire an area which represents a timely and ‘real-life’ case it was hoped to glean national lessons for others facing large scale housing growth, as well as contributing to policies and practices at a local level. The study sought to understand the challenges and opportunities presented by planning for and accommodating significant housing growth in a relatively short space of time.

With a particular emphasis on housing and communities, it considered options for the most efficient and effective strategies and partnerships and what possibilities exist to exploit growth opportunities to ensure maximum area-wide, long term sustainability. This study concludes with a series of recommendations on how best to ‘join up’ and coordinate economic development strategies and aspirations, regeneration requirements and housing growth. This study also highlights the challenges in creating housing markets which can add value—economic and social—and how that value can be captured to meet social policy objectives.
Land-use influences on trip-chaining in Portland, Oregon
Authors: Greenwald M. J. , McNally M. G.
Published: November 2009

This paper examines the nature of land-use-based substitution effects on travel modes, examining the direct impact of land uses inducing trip-making behaviours. These impacts are analysed in the context of trip-chaining, defined here as consolidating two or more non-home activities in a single departure from home. The findings suggest that, rather than strictly promoting one type of transportation over another, the regional impact of localised urban design practices is to consolidate trip-making behaviour closer to the home. As such, urban design ‘carrots’ must be complemented by policy ‘sticks’ in order to promote true exchanges of travel modes.
Integrating counter-terrorist resilience into sustainability
Authors: Coaffee J. , Bosher L.
Published: November 2009

In recent years ideas of resilience have been increasingly embedded within urban planning and design practice as attempts have been made to make the built environment and critical infrastructure more resistant to external risk from natural hazards, particularly those associated with climate change, or from new security challenges facing many cities as a result of the ongoing threat of terrorism. The rapid renaissance of central urban areas in the last decade has given ample opportunities to apply such resilient principles to the construction of new buildings or regeneration areas, facilitated by changes in building regulations and the planning system concerned with broader issues of safety and sustainability. This paper argues that the embedding of resilience into the planning, design and engineering of the built environment is about not only security and community safety concerns but also the environmental benefits that might be achieved by integrating secure and sustainable design. The authors also argue that to date there has been limited integration of security and sustainability construction principles but that significant opportunities exist in the future for such sustainable urbanism to be commonplace.
Molecular size cutoff criteria for screening bioaccumulation potential: Fact or fiction?
Authors: Arnot Jon A , Arnot Michelle I , Mackay Don , Couillard Yves , MacDonald Drew , Bonnell Mark , Doyle Pat
Published: November 2009

It has been asserted that, when screening chemicals for bioaccumulation potential, molecular size cutoff criteria (or indicators) can be applied above which no, or limited, bioaccumulation is expected. The suggested molecular size values have increased over time as more measurements have become available. Most of the proposed criteria have been derived from unevaluated fish bioconcentration factor (BCF) data, and less than 5% of existing organic substances have measured BCFs. We critically review the proposed criteria, first by considering other factors that may also contribute to reduced bioaccumulation for larger molecules, namely, reduced bioavailability in the water column, reduced rate of uptake corresponding to reduced diffusion rates, and the effects of biotransformation and growth dilution. An evaluated BCF and bioaccumulation factor (BAF) database for more than 700 substances and dietary uptake efficiency data are compared against proposed cutoff values. We examine errors associated with interpreting BCF data, particularly for developing molecular size criteria of bioaccumulation potential. Reduced bioaccumulation that is often associated with larger molecular size can be explained by factors other than molecular size, and there is evidence of absorption of molecules exceeding the proposed cutoff criteria. The available data do not support strict cutoff criteria, indicating that the proposed values are incorrect. Rather than assessing bioaccumulation using specific chemical properties in isolation, holistic methods that account for competing rates of uptake and elimination in an organism are recommended. An integrated testing strategy is suggested to improve knowledge of the absorption and bioaccumulation of large substances. Integr Environ Assess Manag 2010;6:210–224. © 2009 SETAC
Evaluation and Optimization of Low-Density Cement: Laboratory Studies and Field Application
Authors: Al-Yami A.S.. S. , Nasr-El-Din H.A.. A. , Al-Humaidi A.S.. S. , Al-Saleh S.H.. H. , Al-Arfaj M.K.. K.
Published: November 2009

Cementing a string in one stage is a challenging task, especially in the presence of weak formations. Cement-slurry losses during placement are highly possible if the equivalent-circulating density (ECD) exceeds 11.0 lbm/gal during placement. A conventional method to overcome this challenge is to use multistage cementing by setting the stage tool above the lost-circulation zone. However, field data indicate that the tool can fail, thus causing serious delay and economic losses. In addition, stage tools are considered weak points and are not good for a long-term seal. A second method for zonal isolation is to use low-density cement (LDC). In this study, we considered cementing the intermediate and production casings in the S-1 (sandstone) and S-2 (carbonate) shallow formations and the BJD (dolomite) deep formation in a single stage using lower-density cement based on hollow microspheres, at 9.4 lbm/gal. The shallow conditions simulated in the laboratory tests were 150°F curing temperature, 2,400-psi conditioning pressure, and 1,800-psi confining pressure for 3 months. The deep conditions were 260°F curing temperature, 5,000-psi conditioning pressure, and 3,000-psi confining pressure, also for 3 months.

Hollow-microspheres cement was used in oil and gas wells without encountering any operational problems. However, the high cost of microspheres cement was a limitation for potential field application. In this study, we present extensive laboratory work to optimize hollow-microspheres LDC by the elimination of microfine cement from the blend. Experimental studies (shrinkage, compressive strength, porosity, gas and brine permeability, and chemical analysis of cement) were conducted to determine the effect of this optimization on the properties of cement.

Data generated during the 3 months supported the use of the optimized system to cement casings at the shallow conditions tested. The removal of microfine cement did not reduce the compressive strength, with an average of 2,013 psi; no shrinkage was observed, and no increase in permeability was noted during the three months of testing. The use of the optimized system did help in bringing cement to the surface in one stage. The cost of the optimized blend was 40% less than conventional hollow-microspheres LDC.

This paper presents case histories that include job design, job execution, and evaluation of the LDC. Field treatments were successful and maintained isolation for more than 3 years.
Short-Term and Long-Term Aspects of a Water Injection Strategy
Authors: Stenger Bruno A. , Al-Katheeri Abdulla B. , Hafez Hafez H. , Al-Kendi Salem A.
Published: November 2009

This paper reviewed the water injection strategy of a supergiant carbonate oil field onshore Abu Dhabi operated by ADCO since 1973. This field was subjected to peripheral waterflooding in order to maintain reservoir pressure and provide a mechanism to sweep the oil. In addition to traditional parameters in waterflooding that control the waterfront shape, such as reservoir heterogeneity, mobility ratio, and depletion rate, the presence of three oil-bearing reservoirs juxtaposed across strike/slip fault planes added a new variable to the complexity. Fault juxtaposition was interpreted to create limited pressure communication and fluid crossflow between reservoirs. The usual way of computing the voidage-replacement ratio (VRR) on the basis of well production and injection rates was, therefore, insufficient to gain a complete understanding of the water-injection strategy. Two different solutions of the VRR were calculated using a full-field reservoir-simulation model history matched for both pressure and saturation changes. After accounting for all surface facilities constraints and under a certain set of assumptions, results of this model indicated that the cumulative liquid crossflow was minimized when certain pressure differences were maintained between these three reservoirs. Alternatively, there were indications that specific instances of higher liquid crossflow could result in additional oil recovery. A simple method to manage production and water-injection targets on a quarterly basis while accounting for the communication between reservoirs was also presented.
Real-Time Downhole Monitoring and Logging Reduced Mud Loss Drastically for High-Pressure Gas Wells in Tarim Basin, China
Authors: ShunChang Wang , YiMing Jiang , ChunJiang Zheng , BaiLin Wu , XinQuan Zheng , JiPing Tang , JinHai Yu , HongHai Fan
Published: November 2009

This paper describes a real-time case study to prevent mud loss and blowouts while drilling a high-pressure gas well in Tarim basin, China. The complex geological structure, high tectonic stresses, and overpressured- and fractured-reservoir formations in the field present a huge challenge to drilling. Of the seven wells drilled in the field in 2005, two did not reach target depths, four experienced huge mud loss, and the other experienced a blowout, resulting in lost control of the well. In early 2006, PetroChina teamed up with Schlumberger and Petroleum University of China to form a collaborative technical group to develop a better understanding of mud-loss and blowout mechanisms. The key component of the study was to establish a mechanical Earth model (MEM) based on offset well data before drilling, update the model using downhole monitoring and logging data during drilling, and predict a safe mud-weight window in real time.

Real-time prediction of a safe mud-weight window with annular-pressure monitoring helped ensure that downhole annular pressure was maintained within the safe mud-weight window during drilling and tripping. The study resulted in a x17 reduction in mud loss and x10 reduction in total nonproductive time (NPT), which is mainly because of mud-loss reduction and elimination of an extra casing. A better understanding of mud-loss/blowout mechanisms was achieved, and guidelines for preventing mud loss/blowouts specific for this gas field were developed.