Sustainable development in seaports: a multi-case study

Seaports are a vital part of the maritime transport industry and have a key role in integrated transport chains and regional economies. However, ports are also sites of environmental pollution originating from land-based activities, ship movements and ports’ own activities. It is, therefore, increasingly recognised that economic growth in ports must be balanced with environmental protection and social progress. This has led to enhanced appreciation of the need for sustainable development (SD) in ports. Whilst much has been written about port environmental practices in European and American ports, there is limited synthesis and comparison of sustainable port practices from different parts of the world. Furthermore, in-depth case analysis and critical examination of the practices and challenges of sustainable port development in a globalised era is limited. This paper presents findings from a qualitative multi-case study that aimed to compare sustainable policies and practices of ports in four different continents and to understand the dilemmas, challenges and opportunities they face in attaining SD. This paper reports findings pertaining to the following research questions: (1) What policy frameworks do ports adopt to attain sustainable development? (2) What specific sustainable practices do ports utilise to manage environmental aspects such as air pollution, water quality, ballast water, dredging and disposal of dredged materials, waste disposal, hazardous substances and land/resource use? (3) What are the driving and constraining forces in achieving sustainable development in ports? Port authorities were studied by reviewing documents and secondary data. The following ports were studied: Port of Long Beach (USA), Port of Rotterdam Authority (The Netherlands), Sydney Ports Corporation (Australia) and Transnet Limited that owns and manages South African ports. Findings of the study demonstrate that the SD paradigm has gained momentum, albeit to differing degrees, in the functioning, organisation and the very ethos of case study ports. An important theme from all case studies is that, whilst there is definite progress towards SD, several practices deemed to be sustainable can be controversial and must be critically examined from the perspectives of different stakeholders including shippers, port-related businesses and the local and global community. Lack of data to monitor environmental impacts, economic costs of implementing sustainable practices and complexities of international, regional and national regulations were other constraining factors. On the other hand, reconciling differences between stakeholders and capitalising on economic opportunities, operational efficiencies and cost savings offered by environmental friendliness can advance port SD. Public–private partnerships and policies negotiated by involving all stakeholders were found to foster port sustainability. Most importantly, this study found that, with globalisation, environmental impacts of ports are not always localised. ‘Sustainable’ practices can have unintended consequences in other parts of the world. Therefore, globalisation necessitates a more critical and global analysis of port operations and environment practices in order to be truly sustainable. Although the scope of the research findings is limited to case study ports, the lessons drawn can be constructively applied to any port operating within an institutional system of structured SD.     

Dynamic Performance of a Bulkhead Flat Car

The dynamic performance of a flat car is studied herein. The performance indices include roll angles, lateral accelerations, center plate loads, side bearing loads, wheel loads and spring deflections. These variables are maximum when the car is running at its critical speed, corresponding to either the rock and roll, or the bounce mode. The Association of American Railroads' (AAR) Flexible Carbody Model was used. The input for vertical track irregularities used in the simulation was generated from published spectra for U.S. Federal Railroad Administration (FRA) Class 4 track. After studying the car's performance with various column loads and spring suspensions, it was found that the most commonly used column load of 4,000 lbs. (17.8 kN) should be used. The spring suspension used in the original car design should also be adopted, in order to avoid spring bottoming.     

A method to estimate trip O‐D patterns using a neural network approach

This paper proposes a method which identifies the trip origin‐destination (O‐D) matrix when many pairs of values for the right hand side column (B) and the bottom row (A) of the matrix are given. The method considers B and A as the cause (input) and effect (output) of a system, respectively, and that the O‐D matrix represents the relationship between the cause and the effect. The relationship which satisfies all pairs of the cause and the effect data exactly may not be identified, but, should a general pattern of the relationship exist, it should emerge when many data sets of B and A are given. Two steps are involved in the method: the first step examines if a consistent O‐D pattern exists; if a pattern is found to exist, the second step identifies the values of the elements of the O‐D matrix. The first step is based on the shape of the possibility distributions of the values of the matrix elements. The second step uses a simple back‐propagation neural network. The method is useful to problems that require identification of the cause‐effect relationship when many sets of data for the cause and effect are available, for example, the station‐to‐station travel pattern on a rapid transit line when the total entering and exiting passengers are known at each station for many different days. The model can also be applied to other transportation problems which involve input and output relation.     

Hydrography and biogeochemistry of the north western Bay of Bengal and the north eastern Arabian Sea during winter monsoon

The north eastern Arabian Sea and the north western Bay of Bengal within the Indian exclusive economic zone were explored for their environmental characteristics during the winter monsoons of 2000 and 2001 respectively. The two regions were found to respond paradoxically to comparable intensities of the atmospheric forcing. There is an asymmetry in the net heat exchange of these two basins with atmosphere because of the varying thickness of barrier layer. During winter, the convective mixing in the Arabian Sea is driven by net heat loss from the ocean, whereas the Bay of Bengal does not contribute to such large heat loss to the atmosphere. It appears that the subduction of high saline Arabian Sea water mass is the mechanism behind the formation of a barrier layer in the northeast Arabian Sea; whereas that in the Bay of Bengal and the southeast Arabian Sea are already established as due to low saline water mass. The weak barrier layer in the Arabian Sea yields to the predominance of convective mixing to bring in nitrate-rich waters from the deeper layers to the surface, thereby supporting enhanced biological production. On the other hand, the river discharge into the Bay of Bengal during this period results in the formation of a thick and stable barrier layer, which insulates vertical mixing and provide oligotrophic condition in the Bay.     

Dynamic Performance of a Bulkhead Flat Car

The dynamic performance of a flat car is studied herein. The performance indices include roll angles, lateral accelerations, center plate loads, side bearing loads, wheel loads and spring deflections. These variables are maximum when the car is running at its critical speed, corresponding to either the rock and roll, or the bounce mode. The Association of American Railroads' (AAR) Flexible Carbody Model was used. The input for vertical track irregularities used in the simulation was generated from published spectra for U.S. Federal Railroad Administration (FRA) Class 4 track. After studying the car's performance with various column loads and spring suspensions, it was found that the most commonly used column load of 4,000 lbs. (17.8 kN) should be used. The spring suspension used in the original car design should also be adopted, in order to avoid spring. bottoming.