Performance of air conditioners with a gas-liquid separation condenser and one-tank laminated evaporator

In this study, a parallel flow condenser and laminated evaporator for an automotive air-conditioning system were modified to improve performance. Gas-liquid separation type condensers, in which the condenser and receiver drier are integrated, and one-tank laminated type evaporators were developed, and their performances were investigated experimentally using HFC-134a. Heat transfer characteristics in the condenser are examined by means of air temperature, air velocity entering the condenser and inlet pressure of the refrigerant; heat transfer characteristics in the evaporator are examined by means of air temperature, relative humidity, flow rate of air, outlet pressure of refrigerant and superheat. Pressure drops for both evaporator and condenser are also measured, and correlations for pressure drop are derived for the condenser and evaporator, respectively. Air velocity and mass flow rate of the refrigerant have a significant effect on the overall heat transfer coefficient, and flow pass is not significantly influenced by the cooling capacity of the condenser. The overall heat transfer coefficient of the evaporator increases as air flow rate, air temperature and relative humidity increases.     

Vibration transmission reduction from a centrifugal turbo blower in a fuel cell electric vehicle

This paper presents a multi-body flexible dynamic analysis of a centrifugal turbo blower for a fuel cell electric vehicle (FCEV) based on the application of computer-aided engineering (CAE) to predict the acceleration at the mount position of the blower. This predicted acceleration is validated by using the measured acceleration data. The numerical simulation for the multi-body flexible dynamics of the blower is used not only to identify the most effective mount among four mounts in an FCEV by controlling the complex stiffness of the isolator, but also to suggest the range of complex stiffness of the isolator at the most effective mount. This numerical simulation technology can be useful for the estimation of the variation of vibration transmission for the structural modification of the turbo blower.     

Modeling,parameter estimation and nonlinear control of automotive electronic throttle using a Rapid-Control Prototyping technique

An electronic throttle consists of a DC motor, spur gears, a return spring, a position sensor, power electronics and an electronic control unit. Fast and precise position control of this electromechanical system is relatively difficult due to very high friction and the strong nonlinearity of the spring. Simple application of linear control, such as PID, fails. In this paper, two new controller structures suitable for different reference signal types are described. The key component of the position controller is the friction compensator based on either/both feedforward or feedback principles. The quality of the resulting behavior was measured using several criteria including the measure of control activity around the equilibrium position. The control activity directly influences the vibration, the noise and the wear of the servo system. The proposed controllers demonstrated superior behavior compared with other published structures.     

Daily Maersk’s impacts on shipper’s supply chain inventories and implications for the liner shipping industry

The liner shipping industry has long been characterized by a weekly sailing frequency and schedule unreliability. This research is motivated by the launch of the revolutionary “Daily Maersk” service in late 2011, which introduced daily departures and “absolute reliability” in the Asia–North Europe trade lane. This article analyzes Daily Maersk’s impacts on a shipper’s supply chain inventories and profound implications for the liner shipping industry as a game changer. The quantitative analyses show that the impact of more frequent sailings is most significant on a shipper’s cycle stock, while improving schedule reliability substantially reduces safety stock and pipeline stock. Daily Maersk is most valuable for products that have high value density, high inventory holding cost ratio, low demand variability, and high service level (SL) requirement. These findings imply that the trend of liner alliance/merger/acquisition is likely to continue or even accelerate as shipping lines consolidate fleet capacity to offer more frequent sailings. Rival carriers may step up their involvement in terminal operations to improve schedule reliability. They also need to rethink about their SL targets and clearly define their preferred customer segments.     

A cause of oversupply and failure in the shipping market: measuring herding behavior effects

ABSTRACT

The shipping market is volatile. In general, the shipping market cycle shows four stages, through—recovery—peak—collapse, while a upward trend lasts for 7~8 years and a downward trend for another 7~8 years. So the market’s bubble is not sustainable but always ends in a recessionary trend. The economic cycle is common knowledge and an axiom of the shipping industry, but many ship-owners take no account of it. Previous study stated that ship-owners’ fears, triggered by a violently changeable market, make them mimic the crowd mind or herd mentality, following market sentiment. This study aims to measure the effects of herding behavior (HB), triggered by market sentiment, on the shipping market. We attempt to address two research questions: (1) How does HB arise, and what course does it follow? (2) How many vessels (or how many tons) were purchased under the influence of HB? We estimate that 50.5% (227.8 vessels) of the total vessels or 30.4% (3,670.2 tons) of the total tonnage were purchased under the influence of HB. Looking at international finance, we found that ship investment HB is a very strong factor of the recent shipping market, at least in Korea.     

Full scale ice sea trials of Korean ice breaking research vessel ‘Araon’ on the big floes near Antarctica

A speed sea trial was performed in the Amundsen Sea in February and March of 2012. The Korean ice breaking research vessel “Araon” was used to check speed performance on the big floes. Two of ice trial cases were carried out. We describe the time history of location, the engine power, and the revolutions per minute during the ice trial, and the trajectory of the ship. Additionally, the measured ice properties are considered and discussed. The ice trial results were analyzed according to variation in ice thicknesses, ice strength, propulsion power, and the speed level of the ship. Our analysis results are compared to model test results and ice trial results. A correction to the target ice thickness was used to compare the power and speed relation in the same ice thickness because it is easy to know the relative speed performance of the ship. The Hamburgische Schiffbau-Versuchs Anstalt method was applied for the correction. The speed of Araon in big floes was higher than the speed in level ice. The speed after the correction at 10 MW of power and 103 cm of ice thickness was 5.4 knots based on analysis results.     

Charting a New Paradigm of Container Hub Port Development Policy: The Asian Doctrine

This paper proposes the conceptual model of the Asian (Port) Doctrine to explain the successful development of top ranking container ports in Asia during the past four decades. This paper draws a new paradigm for the role of government as a third governance approach in addition to Anglo-Saxon and European doctrines by describing how Asian countries have developed container hub ports by investing in infrastructure as social overhead capital to support export-led growth. We survey characteristics and outcomes in major Asian container port developments and one European port in terms of a port development policy. The findings are presented in a comparative overview of government investment in functional elements of port, maritime infrastructure and landside connections to container ports. This paper confirms that the existing two doctrines—Anglo-Saxon and European doctrines—are not sufficient to explain the Asian success in major container port developments. The proposed framework contends that a newly proposed Asian Doctrine can accomplish this with the help of cross-subsidization, strategic and administered port pricing mechanism.     

Incorporating e-Technology to Advantage in a Greener Taxi Industry and its Impact on Driving Performance and Safety

Abstract

New technologies, especially advances in telecommunications, have had profound impacts on everyday life and brought even greater changes to some business models. Taxis represent one of the major modes of transportation in urban areas but they face a number of problems, including their environmental impacts. The status of the taxi industry in Taiwan is revealed and analyzed in this study. A new business model for the extensive and popular use of smart phones is proposed. However, it is important to know whether their use is both effective and safe. Two field experiments were executed to examine the effects on taxi drivers of using a navigation system installed in a GPS PDA phone. The results revealed that the efficiency of drivers using such a portable navigation system was better than those relying on paper maps in unfamiliar urban areas. Furthermore, performance in terms of safety was also better than those who used an on-board navigation system. In summary, incorporating e-technology can promote a taxi company's competitiveness and a driver's performance and safety as well as offer environmental benefits.     

Node-based scheduling method for easy migration from CAN to FlexRay in in-vehicle networking systems

As vehicles become more intelligent, in-vehicle networking (IVN) systems such as controller area network (CAN) are essential for the convenience and safety of drivers. To expand the applicability of IVN systems, attention is currently being focused on chassis networking systems that require increased network capacity and real-time capabilities. FlexRay was developed to replace CAN protocol in chassis networking systems, to remedy the shortage of transmission capacity and unsatisfactory real-time transmission delay of conventional CAN. However, FlexRay network systems require a complex scheduling method, which is a barrier to their implementation as chassis networking systems. In particular, if we want to migrate from a CAN network to a FlexRay network using the well-defined CAN message database, which has been specifically constructed for chassis networking systems by automotive vendors, a new type of scheduling method is necessary to reduce scheduling efforts during the software development process. This paper presents a node-based scheduling method for easy migration from a CAN network to a FlexRay network system. To demonstrate the feasibility of the technique, its performance is evaluated in terms of various software complexity indices.