Corrosion analysis of bulk carriers, Part I: operational parameters influencing corrosion rates

This paper considers the physical processes of corrosion that occur in bulk carriers. Three main types of corrosive environments are identified within a bulk carrier, namely, immersion in seawater, exposure to an enclosed atmosphere, and exposure to porous media. Fundamental variables influencing corrosion in each environment of the cargo hold region, ballast tanks and void spaces are identified. These serve to identify operational parameters that affect bulk carrier corrosion. It is proposed that such parameters can be used to obtain corrosion rate databases representative of vessel operation.     

Lessons in ownership, regulation and management from 100 years of bus transport in Sri Lanka

Sri Lanka observes 100 years of bus passenger transport in 2007. During this period the country has seen different forms of service providers ranging from private sector monopolies to state sector monopolies. It also has seen several changes in state policy ranging from welfare orientated service provision to entire market determined without any regulation. The existing regulated mixed competition is also characterized by poorly equipped regulators. In conclusion, the paper traces the different stages of failure that have led to the poor quality of bus transport services existing at present.     

Influence of injection parameters on the transition from PCCI combustion to diffusion combustion in a small-bore HSDI diesel engine

In this paper, the influence of injection parameters on the transition from Premixed Charge Combustion Ignition (PCCI) combustion to conventional diesel combustion was investigated in an optically accessible High-Speed Direct-Injection (HSDI) diesel engine using multiple injection strategies. The heat release characteristics were analyzed using incylinder pressure for different operating conditions. The whole cycle combustion process was visualized with a high-speed video camera by simultaneously capturing the natural flame luminosity from both the bottom of the optical piston and the side window, showing the three dimensional combustion structure within the combustion chamber. Eight operating conditions were selected to address the influences of injection pressure, injection timing, and fuel quantity of the first injection on the development of second injection combustion. For some cases with early first injection timing and a small fuel quantity, no liquid fuel is found when luminous flame points appear, which shows that premixed combustion occurs for these cases. However, with the increase of first injection fuel quantity and retardation of the first injection timing, the combustion mode transitions from PCCI combustion to diffusion flame combustion, with liquid fuel being injected into the hot flame. The observed combustion phenomena are mainly determined by the ambient temperature and pressure at the start of the second injection event. The start-of-injection ambient conditions are greatly influenced by the first injection timing, fuel quantity, and injection pressure. Small fuel quantity and early injection timing of the first injection event and high injection pressure are preferable for low sooting combustion.     

Rectangular routeing in Smeed's city

A rectangular system of roads is examined in a simple circular city where homes and workplaces are uniformly and independently distributed. Expressions for the number of vehicles crossing a given line segment are derived.     

The Tyre as a Sensor to Estimate Friction

Continuously updated knowledge of the friction potential and the friction demand can help to improve manoeuvrability and thereby safety of vehicles under slippery road conditions. An on line friction estimation method is presented using a simple brush type tyre model. First the method is verified by outdoor experiments using a tyre test trailer. Then the setup of a low-cost measurement system in a vehicle is discussed and results from both simulations and outdoor experiments are presented. Neural networks have been used both for modelling and identification of friction potential and friction demand.     

Plankton distribution and the impact of copepod grazing on primary production in Fram Strait, Greenland Sea

Two hydrobiological transects across the East Greenland Shelf and the open waters of Fram Strait in summer were chosen to illustrate the distribution and production of phyto- and zooplankton in relation to water masses and ice cover. The parameters used were temperature and salinity, inorganic nutrients, chlorophyll a, primary production, phytoplankton species composition, abundance of the dominant herbivorous copepods Calanus finmarchicus, C. glacialis, C. hyperboreus, Metridia longa and egg production of C. finmarchicus and C. glacialis. Grazing impact of copepodites and adults of these four species was modelled for each station by using egg production rates as an index of growth. Seasonal development of plankton communities was closely associated with the extent of the ice cover, hydrographic conditions and the water masses typical of the different hydrographic domains. Four regions were identified from their biological activities and physical environment: The Northeast Water polynya on the East Greenland Shelf, with a springbloom of diatoms and active reproduction of herbivorous copepods. The pack ice region, dominated by small flagellates and negligible grazing activities. The marginal ice zone, with high variability and strong gradients of autotroph production related to eddies and ice tongues, an active microbial loop and low egg production. The open water, with high station-to-station variability of most of the parameters, probably related to hydrographic mesoscale activities. Here, Phaeocystis pouchetii was a prominent species in the phytoplankton communities. Its presence may at least partly be responsible for the generally low egg production in the open waters. Grazing impact on primary production was always small, due to low zooplankton biomass in the polynya and due to low ingestion in the remaining regions.     

The future of transit technology: Lessons from EXPO 86

Expo 86, the World Exposition held last year in Vancouver, Canada, was the largest, special-category world's fair ever staged, with 54 international participants. Given the designated theme of transportation and communications, it is interesting to interpret the statements made by the participants in regard to particular sub-theme areas such as urban transit. This paper reviews the presentations (exhibits, demonstrations, conferences, and seminars) developed by all participants in Expo 86 in regard to urban transit technology, and assesses the significance and direction of technological developments in the areas of vehicle and terminal design, network and system operation and control, and planning and management systems.     

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.     

Impact of Liquid Load Shift on the Braking Characteristics of Partially Filled Tank Vehicles

Braking characteristics of a tractor-tank-semitrailer vehicle is investigated by incorporating the influence of liquid load shift occurring within the partially filled tank. The tank vehicle model is developed by integrating a steady state model of a partially filled tank and a pitch plane model of the vehicle. The liquid load shift occurring in the pitch plane of the vehicle during a braking maneuver is characterized using the change in the gradient of the free surface of liquid and the corresponding shift in the center of gravity of the fluid bulk. The change in normal load on the various axles of the vehicle during the maneuver is then computed to analyze the braking behavior of the partially filled tank vehicle. The braking characteristics of the tank vehicle are then compared to those of an equivalent rigid cargo vehicle in order to study the impact of liquid load shift. Influence of various vehicle and tank design parameters on the braking behavior and wheel lock-up condition is also investigated for typical braking maneuvers.