Factors influencing the choice of flag: empirical evidence

The aim of this paper is to analyse the decision-making process of shipowners when adopting flags of registration. More specifically, it is interested in examining the relative importance of the factors related to an individual company's decision to flag out. The decision to change flag is viwed as similar to any other strategic decision by a profit maximizing firm (shipping company) and therefore those variables which influence the attractiveness, for a given firm, of taking the flagging out decision are analysed. The approach is two-fold in that it employs both qualitative and quantitative analysis. The research is innovative in the sense that it uses an econometric approach and the analysis is based on original data which has been obtained by the authors via a questionnarie and personal interviews with members of the UK shipping industry. The results deal with two particular sectors namely the tanker and general cargo markets and provide an insight into the magnitude and significance of various factors which affect the choice of flag. It is able to provide indications of the likelihood of a particular vessel being flagged out under different cirumstaces and, further, to consider how changes in these circumstances might affect the probability of the event occuring. The paper is structured in six parts comprising an introduction, back ground, methodology, qualitative analysis, econometric analysis, and conclusions.     

The British port transport industry part 2. Employment, working practices and productivity

The abolition of the national Dock Labour Scheme presented with the oppurtunity radically to transform their cargo handling operations. Port employers have seized this oppurtunity and introduced radical changes to workforce compositions, their skills, work practices, and employee relations. The main factor behind these changes has been the desire of operation to minimize labour costs and maximize labour utilization in order to amintain traffic volume and competitive advantage. The short-term effect has been to improve productivity and profitablity(at least for the major port authorities), but it has also produced iinstablity in employee relations ans may in the long term prove counter productive>     

Constrained Optimal Control of Semi-Active Suspension Systems with Preview

Controllers for semi-active suspensions have to account for constraints on damper range, tire force and suspension travel. Two approaches to incorporate these constraints in the design of controllers to minimize peak values in the chassis acceleration are considered. It is assumed that information on the oncoming road elevations (preview) is available. In the soft constraint approach, the constraints on tire force and suspension travel are included in a quadratic performance index. Two clipped optimal control laws, which deal with preview in a different way, are presented. Simulation results with a 2-DOF vehicle model on some rounded pulses show that these laws do not work satisfactorily with respect to the constraints. Therefore, the control problem is reformulated as a constrained optimization problem with hard constraints on tire force and suspension travel. Simulations with the same model on the same rounded pulses show that the hard constraint approach handles the constraints more properly.     

Preview Estimation and Control for (Semi-) Active Suspensions

An active suspension with preview is tested for rounded pulses and a stochastic road surface, and is compared to a passive suspension. The spectacular performance improvement obtained for a step function as road surface is not achieved but the improvement is still significant. The frequency response of the active suspension is determined for comparison with some suspension systems found in literature

An observer to reconstruct the preview information is presented. No model of the road surface is needed. From simulations, it appears that the observer reconstructs both deterministic and stochastic road surfaces satisfactory. However, the influence of measurement noise is not reduced sufficiently.     

Defining domains for models of travel demand

Travel demand models implicitly assume that people respond to changes in a continuous way. This is in contrast to the physical sciences, where discontinuous response is a common phenomenon and is embodied in such concepts as sub-critical and supercritical states.Recent studies have shown that responses to transport policies differ in degree and kind according to the nature and severity of the stimulus and the types of people affected. Response patterns may be categorised by the extent to which they involve adjustments to spatio-temporal or inter-personal linkages. This paper identifies four response domains, with a further distinction between permissive and forced changes.Most travel demand models are designed to operate within an independent, forced (and to a less extent independent permissive) domain and their forecasts become unreliable when responses lie outside that domain. Conversely, a model designed for a more complex domain is unnecessarily cumbersome where simpler responses apply. This paper describes the types of model which are appropriate for each domain and discusses how the effects of a policy may be assigned to the correct domain(s).     

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.