Effective maritime security: conceptual model and empirical evidence

In recent years, the issue of maritime security has become a major concern on the international maritime agenda. One of the issues in this respect is how to enhance security while not jeopardizing organizational efficiency and effectiveness, or to manage security effectively, e.g. facilitating the smooth flows of materials while enhancing supply chain security at the same time. In addressing this issue, we place three cornerstones for the effective management of security in maritime transport: quality management (QM), risk management (RM) and business continuity management (BCM). A conceptual model of effective maritime security, including 13 dimensions and 24 associated critical success factors, is devised following this reasoning. The model was tested through a survey of 119 maritime transport organizations and 25 interviews conducted in Vietnam. Findings support that all proposed 24 factors are valid and should be used as critical factors for success in effectively managing security in maritime transport, in that those involving security incident handling and response are rated as the most important in magnitude, along with security risk assessment, risk-based security mitigation strategies and plans, and senior management commitment and leadership. Managers can use the model designed and tested in this research to develop a checklist of essential components for their company's security management policies, strategies and plans. The use of a universal checklist to evaluate maritime security management would also greatly facilitate benchmarking across organizations in the industry.     

New procedure to estimate the brake warping in a roller tester

Vehicle systems such as the steering, brakes and suspension greatly influence vehicle safety. Therefore, these systems must be inspected to guarantee that they are functioning correctly and to certify that the vehicle is functioning at a satisfactory safety level. In disc brakes, warping is one of the principal reasons for vibrations and noise, and it contributes to diminished brake efficiency. Currently, the International Motor Vehicle Inspection Committee (CITA) demands disc brake warping inspections occur during periodic motor vehicle inspections (PMVIs); however, the procedure to carry out this inspection is not well defined. In this investigation, the warping phenomenon has been analyzed, and a new inspection procedure is proposed.     

Injury analysis of pedestrians in collisions using the pedestrian deformable model

Vehicle safety has become the most important issue in automobile design. However, all efforts to improve safety devices focus on enhancing safety features for occupants. Notably, pedestrians are the second largest category of motor vehicle deaths, after occupants, and account for about 13 percent of motor vehicle deaths. It is essential to design pedestrian-friendly vehicles and pedestrian protection systems to reduce pedestrian fatalities and injuries. To effectively assess pedestrian injuries resulting from vehicle impact, a deformable pedestrian model must be developed for vehicle-pedestrian collision analysis. This study constructs a pedestrian-collision numerical model based on LS-DYNA finite element code. To verify the accuracy of the proposed deformable pedestrian model, experimental data are used in the pedestrian model test. This study applies the proposed model to analyze the dynamic responses and injuries of pedestrians involved in collisions. The modeled results can help assess vehicle pedestrian friendliness and assist in the future development of pedestrian-friendly vehicle technologies.     

Type synthesis of function-generating mechanisms for seat suspensions

Mechanisms with “negative” stiffness are a unique tool used to significantly improve vibration isolation for a vehicle driver via upgrade of the seat suspension. However, connection of such mechanisms to the suspension results in errors in the function generation process, and in most cases, makes motion impossible. An approach to type synthesis is presented in order to make this process more predictable, easy and thus more practical for the upgrade process. Structural classification of the suspensions is presented, and -an atlas of function-generating mechanisms for suspensions that reveals the effect of “negative” stiffness is completed. All of the function-generating mechanisms appear in the atlas as result of enumeration. Structural properties of novel and existing mechanisms are compared. Finally, some advantages in practical use of novel suspensions with “negative” stiffness are illustrated.     

"卫星"号电动车组

介绍了俄罗斯“卫星”号电动车组的设计方案、技术特点以及所采用的设备     

Particle flux, and composition of sedimenting matter, in the Greenland Sea

Vertical flux of particulate material was recorded with moored sediment traps during 1988/1989 in the Greenland Sea at 72°N, 10°W. This region exhibits pronounced seasonal variability in ice cover. Annual fluxes at 500 m water depth were 22. 79, 8.55, 2.39, 3.81 and 0.51 g m⁻² for total flux (dry weight), carbonate particulate biogenic silicate, particulate organic carbon and nitrogen, respectively. Fluxes increased in April, maximum rates of all compounds occurred in May–June, and consistently high total flux rates of around 100 mg m⁻²d⁻¹ prevailed the summer. The increasing flux of biogenic particles measured in April is indicative of an early onset of algal growth in spring. Small pennate diatoms dominated in the trap collections during April, and were still numerous during the high flux period when Thalassiosira species were the most abundant diatoms. During May–June, up to 22% of the Thalassiosira cells collected were viable-looking cells. The faecal pellet flux increased after the May–June event. Therefore we conclude that the diatoms settled as phytodetritus, most likely in rapidly sinking aggregates. From seasonal nutrient profiles it is concluded that diatoms contribute 25% to new production during spring and 50% on an annual basis. More than 50% of newly produced silicate particles are dissolved above the 500 m horizon. High new production during spring does not lead to a pronounced sedimentation pulse of organic matter during spring but elevated vertical export is observed during the entire growth period.     

Gulf of Gdansk spring bloom physical, bio-optical, biological modelling and contact data assimilation

In this study we propose a model of phytoplankton population dynamics in the marine ecosystem, which includes physical, biological and bio-optical parts. As an example we simulate the abnormal 1993 Gulf of Gdansk spring bloom, when extremely high chlorophyll concentrations were observed. For the one-dimensional model we use two different methods of contact chlorophyll observation assimilation to fit a model of “in situ” data. The results are compared with two-dimensional ecosystem modelling based on a barotropic model of wind-driven circulation without assimilation.     

Inter-firm relationships and shipping services: the case of car carriers and automobile importers to the United States

This paper is an initial exploration of inter-industry relationships and linkages in the context of automobile imports to the United States. It is our contention that the nature and structure of the engagement between automobile importers and shipping lines is central to understanding the evolution of the car carrier trade. Building on the literature on transactions costs, and supply and value chains, we show that the regimes currently governing car carriage services range from markets to vertical integration via network forms of engagement. We illustrate this through a detailed discussion of Japanese inter-firm networks and an examination of automobile import data to the US from 1980 to 2000. The findings raise important questions for future research on the impact of inter-industry relationships in various strategic decisions of steamship lines, shippers and port authorities including port entry, port choice and routeing, technological and investment choices, and trajectories of supply chain development.     

Numerical simulations of seasonal and interannual variability of the Black Sea thermohaline circulation

The Black Sea general circulation is simulated by a primitive equation model with active free surface. The forcing is seasonally variable and is based on available climatic data. The model reproduces the main features of the Black Sea circulation, including the river discharge effects on the mean sea level and the Bosphorus outflow. Model results show that the simulated sea surface elevation increases in spring over the whole sea, reaching a maximum in the Danube delta area. In the same region, a minimum is observed in winter. The amplitude of the seasonal oscillations (about 8–12 cm over the whole basin) is of the same order of magnitude as the maximum horizontal variations (about 15–18 cm between the coastal areas and the basin interior). This strong signal formed mostly by river discharges, along with the seasonal variability in the other forcing functions and the local dynamics creates a well-pronounced interannual variability. The performance of the model in simulating the seasonal and interannual variability is critically analyzed, with a special attention on the cold intermediate water formation and the circulation in the upper 150 m. The simulations demonstrate that the source of intermediate waters is on the shelf, and that the water mass in the core of cold intermediate layer changes with time as a response to the periodic forcing at sea surface. This type of variability is characterized by pronounced interannual changes, proving that important differences could exist between water mass structure in different years, even when using identical atmospheric forcings each year.     

Dynamic Response of a Six-axle Locomotive to Random Track Inputs

Spectral analysis techniques are employed to analyze the dynamic response of a six-axle locomotive on tangent track to vertical and lateral random track irregularities. The locomotive is represented by a thirty-nine (39) degrees of freedom model. A linear model is employed by considering small displacements, linear suspension elements and a linear theory for the wheel-rail interaction. Power spectral densities of displacements, velocities and accelerations and the statistical average frequencies of the system are obtained for each degree of freedom. Comparison of the calculated dominating frequencies with existing experimental values shows good agreement. The technique of spectral analysis is an effective tool for model validation, and for the determination of rail vehicle response to track irregularities. The probability functions for the response can be used as a measure for the ride quality of rail vehicles and for the study of fatigue damage of components.