Estimation of capacity utilization in world shipping

The surplus of tonnage which has characterized the shipping industry for over a decade has severely affected profitability and investment opportunities in the industry. This has prompted various schemes to reduce the surplus. A proper assessment of the size of the surplus is an essential requirement for sound policy measures. This paper, which focuses on the tanker sector, examines selected methods used to compute surplus tanker tonnage and proposes other methods. It observes that methods currently used give estimates of surplus tonnage which are basically identical to those obtained by using alternative methods. It concludes that while from 1984 the surplus tanker tonnage has been declining, from 1986 the decline has been rather small and the volume of the surplus is likely to stabilize in the next few years at more or less current levels. However, the paper points out conceptual and practical problems of determining the appropriate base periods or base operating conditions upon which surplus tonnage may be computed.     

Engine clutch torque estimation for parallel-type hybrid electric vehicles

This paper mainly focuses on the accurate estimation of the torque transferred through the engine clutch installed between the engine and the drive motor in parallel-type hybrid electric vehicles. The estimation of the engine clutch torque primarily relies on the forward-direction observer which uses the nominal engine net torque information. To overcome the limitation of using the nominal engine torque information that it may not be accurate during the transient states or due to the influence of external disturbance such as the road condition and wind, the forward-direction observer is supplemented by the use of reverse-direction observer which uses the driveline model and wheel speed measurements. In addition, the drive motor torque information is used to calibrate the nominal engine torque during the idle charging state, so that the driveline characteristic unique to parallel-type hybrid electric vehicle can be utilized to increase the estimation accuracy. Finally, the estimation performance of the designed observer is tested via simulation and experiments based on a real vehicle.     

Adaptive control of the shifting process in automatic transmissions

This paper focuses on the way of keeping shift quality of automatic transmissions consistent in mass production and with mileage accumulation. We investigate the main factors influencing the consistency of shift quality. Test results show that the torque to pressure (T2P) and pressure to current (P2I) characteristics of shifting elements are easily affected. A simulation model of an 8-speed automatic transmission is established to simulate the dynamic process of clutch-to-clutch shift. Simulation results demonstrate that the change of T2P and P2I characteristics has a significant influence on shift quality. In order to compensate for the influences, we develop two adaptive control strategies, i.e., the adaptive control strategies for torque phase and inertia phase. They make use of the measured speed information and time information to evaluate shift quality. Then the control parameters are tuned to adapt to the change of T2P and P2I characteristics. Vehicle tests verify that the developed adaptive control strategies are effective to keep shift quality consistent in mass production and with mileage accumulation.     

Road Safety Strategies: A Comparative Framework and Case Studies

Abstract

This paper proposes a nine‐component analytical framework for developing, comparing, and evaluating road safety strategies. The nine components are: (1) vision; (2) objectives; (3) targets; (4) action plan; (5) evaluation and monitoring; (6) research and development; (7) quantitative modelling; (8) institutional framework; and (9) funding. While the first four components are essential for the formulation of a road safety strategy, the remaining components are key to its successful implementation. To demonstrate the usefulness of this comparative framework, we examine the road safety strategies of six selected administrations: Australia, California, Great Britain, Japan, New Zealand, and Sweden. In these case studies, we extract and highlight good practices in the formulation and implementation of their road safety strategies. The proposed framework also provides a systematic approach for assessing road safety strategies in other administrations. The evaluation of the six case studies forms a benchmarking platform for the planning, formulation, and implementation of good practices for road safety strategies.     

A study of the bi-directional pedestrian flow characteristics at Hong Kong signalized crosswalk facilities

This paper investigates the bi-directional flow characteristics at signalized crosswalk facilities in Hong Kong. Pedestrian flow measurements were conducted at selected signalized crosswalks in Hong Kong urban area with and without the Light Rail Transit (LRT) railway tracks in the median of the carriageway. The pedestrian speed-flow functions for these crosswalk facilities were calibrated. The relationships between the walking speed at capacity and directional distribution of pedestrian flow (or flow ratio) are determined. The effects of different flow ratio on the effective capacity are also investigated. The bi-directional pedestrian flow effects on signalized crosswalk facilities with LRT tracks are found more significant than those without LRT tracks. The result could be used as a basis to improve the assessment of the crosswalk's capacity and to determine the design walking speeds under different flow ratios at signalized crosswalks in Hong Kong and in other Asian cities with similar environments.     

A bi-objective cyclist route choice model

It is widely acknowledged that cyclists choose their route differently to drivers of private vehicles. The route choice decision of commuter drivers is often modelled with one objective, to reduce their generalised travel cost, which is a monetary value representing the combined travel time and vehicle operating cost. Commuter cyclists, on the other hand, usually have multiple incommensurable objectives when choosing their route: the travel time and the suitability of a route. By suitability we mean non-subjective factors that characterise the suitability of a route for cycling, including safety, traffic volumes, traffic speeds, presence of bicycle lanes, whether the terrain is flat or hilly, etc. While these incommensurable objectives are difficult to be combined into a single objective, it is also important to take into account that each individual cyclist may prioritise differently between travel time and suitability when they choose a route.This paper proposes a novel model to determine the route choice set of commuter cyclists by formulating a bi-objective routing problem. The two objectives considered are travel time and suitability of a route for cycling. Rather than determining a single route for a cyclist, we determine a choice set of optimal alternative routes (efficient routes) from which a cyclist may select one according to their personal preference depending on their perception of travel time versus other route choice criteria considered in the suitability index. This method is then implemented in a case study in Auckland, New Zealand.The study provides a starting point for the trip assignment of cyclists, and with further research, the bi-objective routing model developed can be applied to create a complete travel demand forecast model for cycle trips. We also suggest the application of the developed methodology as an algorithm in an interactive route finder to suggest efficient route choices at different levels of suitability to cyclists and potential cyclists.     

A Theoretical Model on Solvus Line Prediction of Film and Its Application in Nanogranular Al-Cu System

A theoretical model on the solvus line prediction of a film was proposed and applied to a nanogranular Al-Cu system. The calculation results show that the solvus line of solute Cu will markedly lower with the decrease of grain size, namely, the starting temperature of θ(Al_2Cu) precipitation in a nanogranular Al-Cu film will markedly lower than that of conventional coarse grain alloy with the same Cu concentration, and the precipitation temperatures calculated are comparable with the experimental ones. The theoretical model can be simply used to calculate the starting temperature of precipitation in Al-Cu films under three states: ① films with substrate; ② films without substrate; ③ ultrafine grain bulk alloy. As a result, the model is universal, moreover, can be, in principle, used to predict precipitation temperature in other systems.     

Effects of FTP-75 mode vehicle fuel economy improvement due to types of power steering system

This paper focuses on fuel economy improvement according to the type of power steering system. Usually, a conventional power steering system is directly driven by the crankshaft of the engine with a belt, known as HPS (hydraulic power steering). However, there is some inefficiency with this system at high engine speeds. To improve this inefficiency, automobile makers have developed two power steering systems: EHPS (electro-hydraulic power steering) and MDPS (motor-driven power steering) or EPS (electric powered steering). However, there has been insufficient study of effects of the type of power steering system on fuel economy. In this paper, the effect of the type of power steering system on fuel economy is studied experimentally, and calculations of the effect on vehicle fuel economy are presenting using computer simulation with AVL cruise software. The results demonstrate that a 1% vehicle fuel economy improvement can be achieved in a vehicle with an electro-hydraulic power steering system compared to a vehicle with a hydraulic power steering system. In addition, a 1.7% vehicle fuel economy improvement can be achieved using a full electric power steering system in a FTP-75 driving cycle. These results could be used to choose a power steering system.     

OH-radical behavior of unsteady lifted flame based on instantaneous change of the equivalence ratio

In an earlier study, the current authors showed that an unsteady-state lifted flame generated by an equivalence ratio conversion system for a given fuel, was similar to a steady-state lifted flame in terms of the change characteristics from a premixed flame to a critical flame and then to a triple flame with a diffusion flame positioned in the middle according to the concentration difference. Therefore, this study used an OH-PLIF method to investigate the characteristics of a steady-state lifted flame and an unsteady-state lifted flame created under conditions identical to the flames in the preceding study. PLIF (Planar laser induced fluorescence) is practically effective for visualizing the concentration fields within a flame. The resulting OH-radical measurements showed that an unsteady-state lifted flame created under the specific conditions used in this study showed similar tendencies in terms of OH-radical distribution, fluorescence intensity, and liftoff height, to a steady-state lifted flame, thereby confirming that the behavior of an unsteady-state lifted flame can be effectively predicted based on the behavior of a steady-state lifted flame.     

Study of RCM-based maintenance planning for complex structures using soft computing technique

To guarantee the efficiency of maintenance strategies for a complex structure, safety and cost limitations must be considered. This research introduces RCM-based (Reliability Centered Maintenance) life cycle optimization for reasonable maintenance. The design variable is the reliability of each part, which consists of a complex structure, while the objective is to minimize the total cost function in order to maintain the system within the desired system reliability. This research constructs the cost function that can reflect the current operating condition and maintenance characteristics of individual parts by generating essential cost factors. To identify the optimal reliability of each component in a system, this paper uses a Neuro-Evolutionary technique. Additionally, this research analyzes the reliability growth of a system by using the AMSAA (Army Material Systems Analysis Activity) model to estimate the failure rate of each part. The MTBF (Mean Time Between Failure) and the failure rate of the whole system, which is responding to the individual parts, are estimated based on the history data by using neural networks. Finally, this paper presents the optimal life cycle of a complex structure by applying the optimal reliability and the estimated MTBF to the RAMS (Reliability, Availability, Maintainability, and Safety) algorithm.