An economic assessment of the impacts of the MOSE barriers on Venice port activities

To protect Venice from flooding, a number of protective measures have been adopted, including a system of mobile barriers known as MOSE. These separate the lagoon from the surges in the Adriatic Sea but interfere with shipping and on port activities. We estimate direct costs on ship traffic resulting from the use of MOSE, i.e., the additional costs of longer waiting time when passing through the Venice Lagoon. Our estimate uses inputs from a hydrodynamic model applied to the ship traffic between 2000 and 2002 and indicate that these costs range from €347,943 to €1.3 million a year, depending on the hypotheses adopted.     

A transit ridership‐revenue model

The paper outlines the theoretical underpinnings of an urban mass transit revenue and ridership model designed to provide medium term forecasts of future trends in situations of data sparsity. The specific example laid out in the paper relates to the Greater Vancouver Regional District but the framework is of general applicability. Much of the informational input at the initial stage is of a general kind and details of the specific transit system and local area are of the sort which should be readily available to most urban authorities. The model developed is designed for use on a desk‐top micro‐computer and offers an inter‐active method of forecasting. The operator has the facility to both consider fare policy sensitivity and review alternative scenarios about future trends in exogenous factors. A selection of forecasts developed for the GVRD is provided to reveal the main features of the approach.     

Energy efficiency,technological change and the dieselization of agriculture in the United States

This study focuses on the increase in the relative importance of diesel fuel consumption on farms in the United States over the 1971–1989 period. Four factors are identified as being central to the observed trend. These include the relative efficiency of diesel powered equipment versus gasoline powered equipment, technological changes that have impacted energy efficiency, the trend towards larger farms, and the enhanced energy conservation by farmers as a result of the adoption of reduced tillage practices.     

Experimental study and 3D CFD analysis on the optimization of throttle angle for a convergent vortex tube

Seven adjustments of convergent-type Vortex Tube (VT) with different throttle angles were applied. The adjustments were made to analyze the influences of such angles on cold and hot temperature drops as well as flow structures inside the VTs. An experimental setup was designed, and tests were performed on different convergent VT configurations at injection pressures ranging from 0.45 to 0.65 MPa. The angles of the throttle valve were arranged between 30° to 90°, and the numbers of injection nozzles ranged between 2 and 6. Laboratory results indicated that the maximum hot and cold temperature drops ranged from 23.24 to 35 K and from 22.87 to 32.88 K, respectively, at four injection nozzles. Results also showed that temperature drop is a function of hot throttle valve angle with the maximum hot and cold temperature drops depending on the angle applied. We used graphs to demonstrate the changes in the cold and hot temperature drops with respect to hot throttle angle values. These values were interpreted and evaluated to determine the optimum angle, which was 60°. The CFD outputs agreed very well with the laboratory results. The proposed CFD results can help future researchers gain good insights into the complicated separation process taking place inside the VTs.     

The political economy of ports in the United States and Great Britain

Abstract

This is an exploration of the political economy of ports in the United States and Great Britain. A number of technical, economic, and political issues concerning ports are examined. Particular attention is paid to the institutional evolution of ports from private to public ownership, and its consequences for port efficiency. The paper concludes with a set of recommendations designed to reverse the trend toward port nationalization in both countries.     

Productivity change in transport: a survey

Because of the importance of transport in promoting economic development, there has been a long‐standing interest in the performance of transport industries and in the conditions which are likely to promote productivity growth. Fundamental to any debate on the subject, though, is the need to advance a satisfactory account of production and a way of deciding when productive performance has changed. This paper points out that there are pitfalls in the common practice of using measures such as output per man‐hour as an indicator of productivity and argues that a thorough understanding of the relationships between inputs and outputs can proceed from a knowledge of the economic theory of production.

The paper describes the relevant theoretical concepts and then examines applications of that theory in transport industries. It transpires that there is a growing literature on the subject, demonstrating a worldwide and multimodal interest in developing more rigorous and satisfying ways of measuring and analysing productivity difference. The techniques employed range from the more complex models at the forefront of economic theory, to rudimentary methods which are, at best, capable of testing only the simplest types of hypotheses. Nevertheless, it is argued that these studies have achieved a remarkable degree of success in enhancing analysis.

There can be no doubt that techniques will undergo further developments. However, it is likely that the greatest successes will come about through improvements in data which will permit applications of more complex, but proven techniques of analysis in relatively neglected areas such as road and maritime transport.     

Exploring the drivers of light rail ridership: an empirical route level analysis of selected Australian,North American and European systems

This paper explores the relative influence of factors affecting light rail ridership on 57 light rail routes in Australia, Europe and North America through an empirical examination of route level data. Previous research suggests a wide range of possible ridership drivers but is mixed in clarifying major influences. A multiple-regression analysis of route level ridership (boardings per route km) and catchment residential and employment density, car ownership, service level, speed, stop spacing, share of accessible stops, share of segregated right of away and integrated fares was undertaken. This established a statistically significant model (99% level, R² = 0.76) with five significant variables including service level, routes being in Europe, speed, integrated ticketing and employment density. In general these findings support selected results from previous research. A secondary analysis of service effectiveness measures (boardings/vehicle km, i.e. the relative ridership performance for a given level of service), established a statistically significant model (99% level, R² = 0.67) with 6 significant explanatory variables including being in Europe, speed, employment density, integrated ticketing, track segregation and service level. The latter implies that a higher frequency results in higher service effectiveness. Overall the research findings stress the importance of providing a high level of service as a major driver of light rail ridership. The ‘European Factor’ is also an important though intriguing influence but its cause remains unclear and requires further research to elaborate its nature.     

AUV hull shape design based on desired pressure distribution

The role of autonomous underwater vehicles (AUVs) is more important in the quest to reach the deep seas today than ever before. The hull shape of the AUV can differ depending on the special mission considered for the vehicle. Therefore, different types of algorithms for the body shape design of these kinds of vehicles are being developed every day. In the current work, a new procedure has been proposed for designing the body shape of an AUV. Using this method which is based on a desired pressure distribution, it is possible to obtain the desired hull shape design. Artificial neural network algorithm has been used for this purpose. Preliminary data for training and testing of the network have been obtained from CFD simulation of the flow around the body of Hydrolab500 AUV. In this regard, pressure distribution has been evaluated around each body by changing the nose and tail profile of AUV. The results obtained from this research indicate that a body correlated to the desired pressure can be designed properly.     

Lessons from a Multi-Scale Historical Reconstruction of Newfoundland and Labrador Fisheries

In this article we use a multi-scale, multi-method historical reconstruction of post– World War II social-ecological interactions within fisheries in Newfoundland and Labrador to explore the dynamics of intensification, expansion, and resource degradation in managed fisheries. Our case study draws on landings statistics, other archival information, and the Local Ecological Knowledge (LEK) of fish harvesters to explore these linked dynamics at the macro, meso, and micro levels. By some measures we found large scale trends toward intensification of effort leading to over-harvesting at macro (province wide) levels. At the same time, at the local level (micro-scale) and across sectors and regions (the meso-scale), we found highly fluid fishing practices and a complex suite of stated motivations for change. As a basis for effective governance, an understanding of the dynamics of interactive restructuring in social ecological systems will require multi-scale analyses that are sensitive to this complexity.     

A study of tour formation: pre-, during,and post-recession analysis

Transportation - This study examines changes in activity-travel patterns of employed people during a recession by using a tour-based representation of the activity-based approach. The term tour is...