Development of vessel traffic services: Legal considerations

Legislative measures, rather than further technological advances, are needed if there is to be any extensive development of Vessel Traffic Services. Reasons are given why this conclusion differs from that of the COST 301 Study with respect to legal liability of Vessel Traffic Services.     

胆石中游离和结合胆汁酸定量分析研究(薄层扫描色谱法)

在付立叶变换红外光谱(FT-IR)定性分类胆石的基础上,用薄层扫描色谱法进行胆石中游离和结合胆汁酸的定量分析研究。60例胆石经FT-IR 分为7种类型:胆固醇结石,胆固醇混合石、胆色素混合石、色素新型石、类色素型石、黑石磷酸盐型和黑石蛋白型。本文将从不同类型胆石游离和结合胆汁酸含量的差异,探讨胆汁酸在胆石成因中的作用.     

Vehicle dispatching with competition

This paper considers a vehicle dispatching problem with competition. For Poisson arrival processes, three dispatching policies are considered, (i) a C-policy, consisting in sending a vehicle as soon as it is filled to capacity C, (ii) a T-policy, assuming an infinite capacity and consisting in sending a vehicle every T periods and (iii) a (T, C)-policy consisting in sending a vehicle every T periods or whenever it is filled to capacity C, whichever comes first. Two firm models with cooperating and non-cooperating solution modes are resolved and results summarized in a table. Applications and examples are resolved for demonstration purposes.     

On the definition of traffic equilibrium

Three alternative definitions of traffic equilibrium are compared in terms of the mechanisms of route-choice inherent in them. These definitions are the usual Wardrop equilibrium and user-optimised ones and a new one. Conditions on the cost function are established under which the Wardrop definition is equivalent to each of the other two. Some circumstances are identified in which these conditions are satisfied. A detailed discussion is given of an example in which these conditions are not satisfied and the three definitions are not equivalent.     

Microbial community structure in the marginal ice zone of the Bellingshausen Sea

Phytoplankton, bacteria and microzooplankton were investigated on a transect in the Bellingshausen Sea during the ice melt period in November–December 1992. The transect along the 85°W meridian comprised seven stations that progressed from solid pack-ice (70°S), through melting ice into open water (67°S). The abundance, biomass and taxonomic composition were determined for each component of the microbial community. The phytoplankton was mostly dominated by diatoms, particularly small (<20 μm) species. Diatom abundance ranged from 66 000 cells l⁻¹ under the ice to 410 000 cells l⁻¹ in open water. Phytoplankton biomass varied from <1 to 167 mg C m⁻³, with diatoms comprising 89–95% of the total biomass in open water and autotrophic nanoflagellates comprising 57% under the ice. The standing stocks of autotrophs in the mixed layer ranged from 95 mg C m⁻² under the pack-ice to 9478 mg C m⁻² in open waters. Bacterial abundance in ice-covered and open water stations varied from 1.1 to 5.5×10⁸ cells l⁻¹. Bacterial biomass ranged from 2.4 mg C m⁻³ under pack-ice to an average of 14 mg C m⁻³ in open water. The microzooplankton consisted mainly of aloricate oligotrich ciliates and heterotrophic dinoflagellates and these were most abundant in open waters. Their biomass varied between 0.2 and 54 mg C m⁻³ with a minimum at depth under the ice and maximum in open surface waters. Microheterotrophic standing stocks varied between 396 mg C m⁻² under pack-ice and 3677 mg C m⁻² in the open waters. The standing stocks of the total microbial community increased consistently from 491 mg C m⁻² at the ice station to 13 155 mg C m⁻² in open waters, reflecting the productive response of the community to ice-melt. The composition of the microbial community also shifted markedly from one dominated by heterotrophs (82% of microbial stocks) at the ice station to one dominated by autotrophs (73% of microbial stocks) in the open water. Our estimates suggest that the microbial community comprised >100% of the total particulate organic carbon (POC) under the ice and 62–66% of the measured POC in the open waters.     

A conceptual framework of individual activity program generation

The research in this paper attempts to better understand the process by which activities are generated at an individual level. Activity-based travel analyses have gained popularity in recent years because they recognize the complexity of activity behavior and view travel as a derivative of this behavior. Most activity-based studies have focused on the spatial and temporal linkage of trips; that is, the scheduling of activities. They consider the agenda of activities for participation, and associated attributes of the activity participation (such as mode to activity and location of activity performance), as predetermined. This paper develops a comprehensive conceptual framework of the relatively unexplored area of activity agenda generation. Such a framework will be valuable in empirical modeling of activity generation behavior. A subsequent paper focuses on translating a part of this conceptual framework into an empirical model.     

The advantages of a high density,mixed land use,linear urban development

This paper describes the land use and transport characteristics of a strip of urban development located along the northern shore of Hong Kong Island. The strip of land, with an area of 22.5 sq. km, is 17 km long and has an average width of 1.3 km. It has a population of approximately one million and provides over 700,000 jobs. Despite its small size, it accommodates the CBD, residential districts, shopping complexes as well as most of the civic/institutional facilities that a city needs. Its urban form is linear not by design but by default – the topography of the area has constrained the development from spreading sideways. Surprisingly however, apart from economy in land utilization, it is considered to possess three other good qualities: high accessibility enjoyed by residents; few roads and commercially viable public transport. Its travel characteristics are analyzed, using results of a home interview survey conducted by the Government in 1992. In addition, various statistics published by the Government and public transport authorities are also used in the analysis.     

The Variable Linear Transmission for Regenerative Damping in Vehicle Suspension Control

This paper introduces the concept of regenerative damping in vibration control, die storage of energy normally dissipated by a passive viscous damper. A device, the Variable Linear Transmission, is proposed to accomplish this task. Analysis of die proposed device as a damper in a typical passenger vehicle is conducted for die cases in which the device's active component operates ideally and with activation dynamics included. Results indicate that regenerative vibration control is feasible and can provide damping nearly identical to that of a passive viscous damper while storing the damped energy.     

Development of simplified analytical methods for predicting the response of offshore structures to blast and fire loading

This paper discusses structural response to blast loading and temperature changes in fires. Both extreme events can be modelled using a range of analytical techniques from simple methodologies to the very complicated finite element analysis. The relatively simple techniques are appropriate for this type of problem and degree of accuracy required given the level of uncertainty in the loading. Given specific boundary conditions and physical properties, the methodologies proposed in the paper provide as good estimates of the dynamic response to blast loading and temperature increases in fires as the more sophisticated finite element method. Experimental data compares well with the analytical results.