An Analysis of a Civil Aircraft Main Gear Shimmy Failure

A dynamical model is presented to analyse the stability of motion of the two-wheeled 'Fokker F.28-like' landing gear including tyres. The model is equally applicable to similar landing gears. The influence of the introduction of a specially designed torsional damper on the dynamical behaviour of the landing gear-tyre combination is investigated. Results of the stability calculations are supported by test results.     

Benzene concentrations on board chemical tankers

Maritime transport of benzene is regulated by the International Maritime Organisation (IMO). Two important guidelines for a ship’s crew in this matter are IMO circulars 1095 and 1220. The first one describes the minimum safety standards for ships carrying liquids in bulk containing benzene while circular 1220 deals with structural guidelines for new ships carrying liquids in bulk containing benzene, but also technical developments could help in improving safety and health protection on board chemical tankers carrying benzene in bulk. The aim of the present paper is to determine the benzene concentration in the working and living environment on board a modern chemical tanker carrying benzene in bulk, where all safety, technical and operational procedures described by IMO in the above-mentioned circulars are followed. During specific cargo operations, we measured the benzene concentrations on different locations on board by means of Radiello® passive diffusive samplers. Despite all measures taken, we found an important difference in benzene concentration between operations with a benzene cargo compared to operations without benzene on board, as well as inside and outside the accommodation. Moreover, even during discharge operations, where the emission is theoretically zero, we found an important increase in the benzene concentration. In addition, we found less favourable results for the engine room.     

Commuting trips within tours: how is commuting related to land use?

Studies that model the effects of land use on commuting generally use a trip-based approach or a more aggregated individual-based approach: i.e. commuting is conceptualized in terms of modal choice, distance and time per single trip, or in terms of daily commuting distance or time. However, people try to schedule activities in a daily pattern and, thus, consider tours instead of trips. Data from the 2000 to 2001 Travel Behaviour Survey in Ghent (Belgium) illustrate that car use and commuting times significantly differ between commuting trips within work-only tours and more complex tours. Therefore, this paper considers trip-related decisions simultaneously with tour-related decisions. A multiple group structural equation model (SEM) confirmed that the relationship between land use and commuting differs between work-only tours and more complex tours. Trips should be considered within tours in order to correctly understand the effect of land use scenarios such as densifying on commuting. Moreover, the use of multiple group SEM enabled us to address the issue of the complex nature of commuting. Due to interactions between various explanatory variables, land use patterns do not always have the presumed effect on commuting. Land use policy can successfully influence commuting, but only if it simultaneously accounts for the effects on car availability, car use, commuting distance and commuting time.     

Technical changes and impacts on economic performance of dry bulk vessels

Spurred by the expanding bulk shipping and technological innovations, dry bulk vessels have gained considerable development in ship types, ship design, and operation since the invention of the first specialized dry bulk carrier in the early 1950s. However, questions like: what changes in technical specifications have occurred for dry bulk vessels during the past four decades; what triggered these changes and what impacts have these specific changes had on shipping costs or earnings potential, have never been examined systematically in previous work. Subsequently, this article attempts to investigate changes in main technical specifications and relationships between the main technical variables and their economic performance measured by costs and revenues of dry bulk carriers. Technical changes in speed, deadweight, lightweight, and engines are checked for the main types of dry bulk vessels, and trends revealed in these developments are demonstrated to be the consequences of both technical improvement and economical considerations. Additionally, it has been found that the earnings potential differs much from dry bulk vessels with different technical specifications. This can be manifested in the sensitivity analysis. The analysis of this article may contain useful information to practitioners of dry bulk shipping in guiding their market decisions about ship building and operations.     

Traffic Noise in Europe: A Comparison of Calculation Methods,Noise Indices and Noise Standards for Road and Railroad Traffic in Europe

The demand for inland freight transport in Europe is mainly met by road transport, leading to unsustainable impacts such as air pollution, greenhouse gas emissions and congestion. Since rail transport has lower externalities than road transport, a modal shift from road to rail is an accepted policy goal for achieving a more sustainable and competitive transport system. However, intermodal road–rail transport is mainly competitive for long-distance transport, and as a consequence, the potential for modal shift is limited. The cost efficiency of road–rail intermodal transport is particularly sensitive to pre- and post-haulage (PPH) costs, since this activity typically has a larger cost compared with its share of the total distance in the transport chain. For intermodal transportation over shorter distances, for example, below 300 km and where there are substantial PPH activities at both ends of the chain, the competitiveness of the intermodal transport system compared with that of direct road is low. Improving the efficiency of PPH activities is, therefore, of utmost importance for the competitiveness of the intermodal transport system. This paper looks into the issue of improving the cost efficiency of an intermodal transport chain by implementing an innovative and flexible legal framework regarding the PPH activities in the chain. By extending the legal framework with exemptions for longer vehicles in PPH, the cost efficiency could be greatly improved. The purpose of such a framework is to allow and enable, for PPH exclusively, the use of 2?×?40 foot or even two semi-trailers using only one vehicle in the context of the Swedish regulatory framework. This paper develops a strategic calculation model for assessing and investigating the consequences of such a framework and investigates the framework's potential in terms of cost efficiency. The model in combination with a sensitivity analysis of input variables gives a comprehensive understanding of the effects of PPH under different circumstances. From the results, it is evident that there are substantial positive effects associated with a PPH framework of longer vehicles. Results indicate that a typical shipper may experience cost reductions of about 5–10% of the total costs of the intermodal transport chain. In summary, a more innovative and flexible legal framework regarding vehicle length in the PPH links can contribute to a greater modal shift, improved cost efficiency and more environmentally friendly transportation systems.     

Substantial Changes and Their Impact on Mobility: A Typology and an Overview of the Literature

During the past 40 years, mobility patterns have enduringly changed several times as a result of the occurrence of a number “substantial changes”. Examples of such substantial changes are the rapid emergence of affordable air travel, the oil crises, and profound ICT developments. To most researchers and policy-makers in transportation, it seems more than likely that the next 40 years will also witness a number of substantial changes, some of which might even have larger impacts on mobility than the ones described above. However, literature on substantial changes and their impact on mobility are difficult to access as it is spread across different research fields and suffers from ambiguous use of terminology. As a result, overview of the literature on substantial changes and their findings is missing and discussions on the impacts on future mobility of potential substantial changes are hampered. To overcome these problems, this paper (1) proposes a typology of substantial changes and (2) ties together and reviews the scholarly literature that has focused on identifying the impacts of past substantial changes on mobility patterns. In this paper, we show how the proposed typology on substantial changes can be applied to contemplate on substantial changes and on their impacts.     

How to turn an innovative concept into a success? An application to seaport-related innovation

The main objective of this paper is ‘to assess the conditions, including policy support, under which innovative concepts have a high chance of getting adopted and being successful’. The work will start from the state-of-the-art with the following goals targeted. Firstly, to identify the paths that new innovative concepts usually follow, what key determinants are, which actors are involved, and what policy has been doing and can do. As part of this, a typology of variables is established, which will be the basis for the identification of successful adoption paths. Illustrations are provided of the performance of different innovative concepts in the seaport sector. A further goal is to propose policy recommendations, identify best practices, barriers to implementation and transferability of innovative concepts and processes. Finally, the research establishes developments needed in assessment methods and a methodological framework if innovative concepts are introduced.     

Combining Intermodal Transport With Electric Vehicles: Towards More Sustainable Solutions

Abstract

This paper analyses the feasibility of incorporating electric or hybrid vehicles in intermodal transport for the transportation of containers in the pre- and post haulage (PPH) operation. In Europe, the intermodal transport market is being strongly supported, as it is seen as one of the keystones of a sustainable mobility system policy. The introduction of environmentally friendly electric/hybrid vehicles for the pre- and post haulage operation would mean a further enhancement leading to a more complete ecological intermodal transport chain. PPH operations are usually no longer than 30 km, and, hence, could possibly be handled by electric or hybrid vehicles.

Hybrid electric vehicles (HEV) combine electric and other drive systems, such as internal combustion engines, gas turbines and fuel cells. Hybrid electric vehicles merge the zero pollution and high efficiency benefits of electric traction with the high fuel energy density benefits of an energy source or thermal engine. The use of electrically driven vehicles for goods distribution has already been successfully proven in international demonstration projects, such as ELCIDIS. Transport of intermodal units (such as ISO containers), however, requires electric/hybrid heavy-duty goods vehicles, which are not readily available on the market, but for which the technology exists.

Different possibilities are assessed as to their technical, financial, organizational and environmental feasibility and suitability. This analysis is based on a typical mission for pre-and post haulage operations, such as type of trips, distance, frequency, urban/suburban, etc.     

Adaptive choice behaviour of motorists in congested shopping centre parking lots

Currently existing models of parking choice behaviour typically focus on the choice of types of parking spaces. Implicitly these models assume that motorists have a free choice in that spaces are available. The adaptive behaviour which they reveal when faced with congested parking spaces is not explicitly modelled. The aim of this paper is to contribute to the growing literature on parking choice modelling by developing and testing a stated choice model of adaptive behaviour of motorists who are faced with fully occupied parking lots. The findings of the analyses indicate that the model performs satisfactory as indicated by its goodness-of-fit and the fact that all significant parameters were in anticipated directions.     

The identification of factors influencing destination choice: An application of the repertory grid methodology

A common problem of all cognitive-behavioural models of destination choice is that of the identification of factors influencing the behaviour of interest. This paper considers the applicability of Kelly's repertory grid methodology to identify the factors influencing consumer choice of shopping centres. Firstly, some methodological issues in the assessment of the relative importance people attach to certain variables in deciding where to shop are discussed. Secondly, the main findings of an application of the repertory grid methodology are presented. The paper concludes by discussing some implications of the measurement of the determinants of choice behaviour and the construction of mathematical models of destination choice.