Large oil tankers and the Baltic marine environment: A statistical survey

The short Baltic export route for Russian oil is an attractive source of supply for the European energy market. The article examines the Russian oil export trade in the Baltic based on Automatic Identification System (AIS) data from 2005 matched with supplementary data. The first part of the article gives a survey of activities and characteristics of 261 large crude oil tankers, their flag states and owner countries. The second part views the data in the context of accidental oil spill risk. Greek and Russian owners are leading carriers in this trade. Russia plays a double leading role as oil exporter and shipowning country, securing major cargo shares for nationally owned vessels, while also giving a preferential spot in the trade to Greek owners. Where environmental aspects are concerned, previous research has linked vessel characteristics with the risk of casualty. Knowledge of flag, age, ownership and activity levels adds useful information about environmental risk. The data show that flags associated with very high casualty or detention probabilities were represented by 18% of the activity in this trade. Older vessels have a similar share, and at this particular time probably represent the more serious threat of accidental oil spills.     

Blast loaded plates

Plates form one of the basic elements of structures. Land-based structures may be subjected to air blast loads during combat environment or terrorist attack, while marine structures may be subjected to either air blast by the attack of a missile above the water surface or an underwater explosion by the attack of a torpedo or a mine or a depth charge and an aircraft structure may be subjected to an in-flight attack by on-board explosive devices. Furthermore, gas explosion occurs in offshore installations and industries. This review focuses on the phenomenological evolution of blast damage of plates.     

The construction and use of continuous autoregressive models for traffic indices

This article discusses the use of continuous autoregressive models to describe the behavior of traffic indices. From discretely sampled data, second-order differential equation models are constructed to represent dynamic traffic fluctuations as the response of a linear system to a stochastic forcing function. The results are compared to the more common M/G/∞ queueing model approach, and the analysis is demonstrated on time series of aircraft concentration in thirty-one enroute air traffic control sectors.     

Finite element modeling of suction anchors under combined loading

Suction anchors are subjected to inclined, quasi-horizontal or quasi-vertical loadings. The type of the structure and depth of water govern the inclination of the load. Under this load condition, suction anchor experiences a combination of horizontal and vertical translations, and rotation. Therefore the soil's reaction to this load condition can be idealized as horizontal and vertical loadings, together with a moment. The magnitude and combination of the reactions depend on the load inclination, soil property and the point at which the load is applied. The behavior of the suction anchor subjected to the combined V–H-M loading is elaborated in this paper. This is to observe the effects of soil properties on the failure mechanism and ultimate capacity of the foundation. This was achieved by applying the pure horizontal and vertical displacements, and rotation and their combinations to the foundation, on V–H, V-M and H-M spaces and the yield-locus created for each space. The general purpose finite element program DIANA was used for this study. Non-linear analysis was conducted using a simplified elastic-perfectly-plastic model with Von-Mises yield criterion for saturated and consolidated clay.     

In-use measurement of the activity, fuel use, and emissions of eight cement mixer trucks operated on each of petroleum diesel and soy-based B20 biodiesel

In-use micro-scale fuel use and emission rates were measured for eight cement mixer trucks using a portable emission measurement system. Each vehicle was tested on petroleum diesel and B20 biodiesel. Average fuel use and emission rates increase monotonically versus engine manifold absolute pressure. A typical duty cycle includes loading at a cement plant, transit while loaded from the cement plant to work site, creeping in a queue of vehicles at the worksite, unloading, and transit without load from the site to the plant. For B20 versus petroleum diesel, there is no significant change in the rate of fuel use, CO₂ emissions, and NO emissions, and significant decreases in emissions for CO, hydrocarbons, and particulate matter. For loaded versus unloaded onroad travel, fuel use and CO₂ emissions rates are approximately 60% higher and the rates for other pollutants are approximately 30–50% higher. A substantial portion of cycle emissions occurred at the work site. Inter-vehicle and intra-cycle variability are also quantified using the micro-scale methodology.     

A model of the travel to work limits of parents

This paper considers the length of time that parents are willing to travel to an existing or new job. Using data for over 12,000 parents it finds that many characteristics were associated with being less likely to be willing to travel to work for at least an hour (roundtrip). These include: being a women, those out of work, having children under 5, being a lone parent and using formal childcare. Professionals and associate professions were more willing to travel for longer periods. In terms of location, those in accessible small towns and rural areas were willing to travel more than those in larger urban areas and those in remote rural areas willing to travel most. Policy implications are also set out.     

Maintenance optimization for transportation systems with demand responsiveness

We present a quadratic programming framework to address the problem of finding optimal maintenance policies for multifacility transportation systems. The proposed model provides a computationally-appealing framework to support decision making, while accounting for functional interdependencies that link the facilities that comprise these systems. In particular, the formulation explicitly captures the bidirectional relationship between demand and deterioration. That is, the state of a facility, i.e., its condition or capacity, impacts the demand/traffic; while simultaneously, demand determines a facility’s deterioration rate. The elements that comprise transportation systems are linked because the state of a facility can impact demand at other facilities. We provide a series of numerical examples to illustrate the advantages of the proposed framework. Specifically, we analyze simple network topologies and traffic patterns where it is optimal to coordinate (synchronize or alternate) interventions for clusters of facilities in transportation systems.     

Satellite remote sensing of the Polar Oceans

The advent of satellite remote sensing has opened doors for detailed monitoring of the polar regions at a relatively high temporal resolution. Several sensors have been developed over the years, the most noteworthy of which are the visible, the infrared and the microwave systems. The visible and infrared systems are most intelligible to the human eye and provide images that have good spatial resolution. However, because of persistent cloudiness and several months of darkness in the polar regions the most promising sensors appear to be the microwave systems, both passive and active. The passive microwave sensors have been the source of consistently derived ice cover and ice extent data and have provided about fifteen years of global data sets. The Synthetic Aperture Radar (SAR), on the other hand, is noted for very high resolution and a wide range of applications including ice dynamics and ice/wave interaction studies. Nevertheless, there are applications which require the use of the visible and infrared channels, such as the mapping of chlorophyll pigment concentrations in the marginal ice zones which require an ocean color scanner. Also, the infrared sensors are most effective for detecting physical temperatures over cloud-free ice and open water surfaces. Furthermore, altimeters could play an important role in mapping ice surface topography and in evaluating ridge and lead statistics. A review of past, present and future satellite systems, methods and techniques of interpretation and potential applications to the study of the polar oceans is presented.     

Factors affecting tanker safety

The major factors influencing tanker safety are discussed. For the discussion information has been gleaned from maritime labour officials, industry experts and a recent United States Coast Guard study on tanker safety. Results of other tanker safety studies and/or accident reports are also utilized. Some of the factors analysed are the size and age of vessel, licence qualifications for mates and engineers and manning levels. Other factors are those related to or attributed to flags of convenience and the pressure to maintain shipping schedules.