FLUXMANCHE radiotracers measurements: A contribution to the dynamics of the English Channel and North Sea

From 1986 to 1992, ¹²⁵Sb released by the nuclear fuel reprocessing plant at La Hague has been used to study the transfer of waters from mid-Channel areas towards the Straits of Dover. Since 1940, these investigations have formed part of the MAST 53 FLUXMANCHE programme and have involved repeated measurements on a Straits of Dover transect. A discussion of the results is presented here which takes into account new information provided by a hydrodynamic model developed in the framework of FLUXMANCHE; it combines knowledge of the monthly fluxes of water trough the Straits of Dover and week-by-week simulation of the ¹²⁵Sb activities of waters flowing in this aera. It is proposed that soluble radionuclides introduced into the central Channel are transferred towards the Straits of Dover over a time which varies from four to seven months depending on the route taken.     

National-flag shipping: An appraisal of policy options from a Canadian perspective

In this paper the author reviews recent developments in Canadian government policy with regard to national-flag shipping. In response to criticism from various marine interest groups that successive governments have done little to encourage the development of national-flag shipping, federal administrations have taken a more active part in the debate. This has been manifest in several reports produced under the auspices of Transport Canada, which discuss the desirability of using selective tax or fiscal incentives to promote investment in Canadian shipping. The author outlines the arguments for expanding national-flag shipping, relating these to the greater question of what effect these proposed financial measures might have on the use of capital and other resources. He concludes that selective preferential taxation may be justified by the repatriation of shipping activities now offshore and avoidance of further shifts of manpower and capital offshore.     

Behavioral analysis and transportation planning: Inputs to transit planning

The purpose of this paper is to discuss various types of behavioral data of potential relevance to transit planning. In particular a distinction is drawn between behavorial information regarding feelings, attitudes, opinions, and the like and more sophisticated types of data dealing with individuals' intentions to respond in certain ways given certain configurations of stimuli (transportation variables). The former is shown to be an important input to incremental planning, i.e., where information as to system performance is desired. The latter is shown to be critical to decisions regarding manipulations of transit system parameters, i.e., where knowledge of the outcome of manipulating system parameters is desired.A methodological example as to how the first type of data — informational level data — can be collected and utilized in system planning is presented. Specifically, data collected along the lines of traditional attitude surveys is collected in an attempt to monitor changes in public satisfaction with the Iowa City, Iowa, bus system before and after major system innovations. Implications of the collection and analytical procedures are discussed.This report was produced as part of a program of research and training in urban transportation sponsored by the Urban Mass Transportation Administration of the Department of Transportation.     

Modelling the hydrodynamics and ecosystem of the North-West European continental shelf for operational oceanography

This paper outlines an approach to complex spatio-temporal marine ecosystem modelling as applied to the North Western European Continental Shelf. The model presented here combines an eddy-permitting (approximately 6 km horizontal resolution) baroclinic model, the Proudman Oceanographic Laboratory Coastal Ocean Modelling System (POLCOMS), with the European Regional Seas Ecosystem Model (ERSEM). This has been run within an operational framework using operationally available high resolution atmospheric and lateral boundary forcing, allowing hindcast and near-real time nowcast simulations to be performed. The modelled surface temperature and chlorophyll distributions are presented, and interannual variations discussed. Validation of both the physical and ecosystem submodels show the system to be effective, whilst highlighting areas where improvements in the system can be made. Distinct regional differences in predictive skill are shown. The system presented is ready for operational implementation to provide products and services for use both scientifically and in coastal zone and shelf seas management activities. A programme of work to update the system is already in place.     

The drag on an airplane taking off from a floating runway

The motions of an infinitely long, two-dimensional runway subjected to the dynamic moving load imposed by an airplane taking off are investigated. The runway is assumed to be floating in an inviscid fluid and is initially at equilibrium before the plane takes off. The deformation of the runway resulting from the take-off is wave-like and moves in the same direction as the plane. The maximum drag occurs when the plane catches up with the first wave. Three different runway configurations were considered: a baseline and ones which were ten and one hundred times more flexible than the baseline. For these runways, the added drag to the aircraft was very small, ranging from 1% for the stiffest to 10% for the most flexible runway.     

Some Design Aspects of Anti-Lock Brake Systems for Commercial Vehicles

In this paper a simulation model of tractor-semitrailers suitable for design and performance analysis of anti-lock systems is presented. The model is used to evaluate the effects of various methods of prediction and reselection of the anti-lock system on the braking performance of tractor-semitrailers. The characteristics and the equivalent control logic of a commercially available anti-lock system are examined and its deficiencies are identified. To rectify these deficiencies, improved methods of prediction and reselection are proposed. A comparison of the slip characteristics and braking effectiveness between the proposed and the commercially available systems is made. The effects of various types of control logic on the steerability and directional stability of tractor-semitrailers and on the air consumption of the brake systems will be examined in a separate paper.