Jing‐Xin Dong, Jingjing Xu and Dong‐Ping Song
Empty container repositioning is an important issue in the liner shipping industry. Generally stated, two groups of mathematical models have been proposed to tackle this issue…
Abstract
Purpose
Empty container repositioning is an important issue in the liner shipping industry. Generally stated, two groups of mathematical models have been proposed to tackle this issue. The first group aims to derive time‐dependent origin‐destination matrices that specify the number of empty containers to be repositioned at a decision epoch; the second group aims to develop effective state‐feedback control policies consisting of dynamic decision‐making rules. There is, however, a lack of research into the comparison of these two groups, especially with regard to realistic cases subject to uncertainties. The purpose of this paper is to evaluate and compare the performances of some typical repositioning policies from these two groups and to shed light on their relative merits and suitability in various realistic scenarios.
Design/methodology/approach
Based on a literature review, the paper classifies the current empty container repositioning policies into two categories: origin‐destination (OD) based solutions and state‐based dynamic rules. Typical policies are selected from these two categories and then evaluated using a simulation tool. A range of scenarios are designed based on realistic cases considering the stochastic and dynamic nature of liner services. A comprehensive set of simulation experiments are conducted and analysed; and the relative merits and suitability of the repositioning policies are identified.
Findings
Through a carefully designed comparative study, several research findings are obtained with regard to how the performances of different types of empty container repositioning policies are affected by various factors such as structure of service route, uncertainty of daily demands, and parametric optimisation methods.
Originality/value
The study makes a good attempt to analyse the suitability of different empty container repositioning policies in different scenarios. This is an area that has lacked investigation. The research findings can help shipping companies and other relevant stakeholders better understand the relative merits of different empty container repositioning policies and better tackle the challenges in operating the container shipping system.
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Eon-Seong Lee and Dong-Wook Song
A port plays a crucial role in total logistics chain by conducting its function as a gateway for inbound (import) and outbound (export) cargo operations. The port has…
Abstract
A port plays a crucial role in total logistics chain by conducting its function as a gateway for inbound (import) and outbound (export) cargo operations. The port has traditionally been regarded as a connecting place where handles ships on one side and cargoes on the other side. These interactive functions to be carried out by the port imply that a port organization should be established, maintained and altered in a way that generates a value-adding activity to the whole logistics chain. This paper aims to suggest an alternative direction for a port organization in context of changing global logistics environment so as to be better prepared for the ever-changing business horizon. Such an attempt will provide global logistics and port management with a strategic insight into innovative and responsive port organizational strategies.
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Abdul Kareem Abdul Jawwad and Mofid Mahdi
This article aims to investigate and model the effects of welding-generated thermal cycle on the resulting residual stress distribution and its role in the initiation and…
Abstract
Purpose
This article aims to investigate and model the effects of welding-generated thermal cycle on the resulting residual stress distribution and its role in the initiation and propagation of fatigue failure in thick shaft sections.
Design/methodology/approach
Experimental and numerical techniques were applied in the present study to explore the relationship(s) between welding residual-stress distribution and fatigue failure characteristics in a hydropower generator shaft. Experimental techniques included stereomicroscopy, optical and scanning electron microscopy (SEM), chemical analysis and mechanical testing. Finite element modelling (FEM) was used to model the shaft welding cycle in terms of thermal (temperature) history and the associated development of residual stresses within the weld joint.
Findings
Experimental analyses have confirmed the suitability of the used material for the intended application and confirmed the failure mode to be low cycle fatigue. The observed failure characteristics, however, did not match with the applied loading in terms of design stress levels, directionality and expected crack imitation site(s). FEM results have revealed the presence of a sharp stress peak in excess of 630 MPa (about 74% of material's yield strength) around weld start point and a non-uniform residual stress distribution in both the circumferential and through-thickness directions. The present results have shown very close matching between FEM results and observed failure characteristics.
Practical implications
The present article considers an actual industrial case of a hydropower generator shaft failure. Present results are valuable in providing insight information regarding such failures as well as some preventive design and fabrication measures for the hydropower and other power generation and transmission sector.
Originality/value
The presence of the aforementioned stress peak around welding start/end location and the non-uniform distribution of residual-stress field are in contrast to almost all published results based on some uniformity assumptions. The present FEM results were, however, the only stress distribution scenario capable of explaining the failure considered in the present research.
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This chapter explains the impact containerisation has on the various partners of the global supply chain and the challenges companies encounter and the solutions they use in…
Abstract
This chapter explains the impact containerisation has on the various partners of the global supply chain and the challenges companies encounter and the solutions they use in dealing with empty container repositioning.
The phenomenon of imbalanced container flows and its impact on shipping lines, shippers, container haulage companies, port development and the economy are presented. Special attention is given to explain the many solutions companies use to reduce the impact of empty container repositioning, hence tracing out the past research that led to these solutions and pointing to potentially new research directions in the future.
Because of the widespread use of containerisation and the imbalanced container flows that results from globalisation, empty container repositioning will be an ongoing issue for the maritime logistics industry. Many solutions are being used, but there is room for improvement and more research is needed.
Empty container repositioning is an important issue but has not been deemed as such in the literature. This chapter explains the reasons it is important and that its impact is not limited to shipping lines only but affects the whole supply chain.
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Khaled Hussein and Dong-Wook Song
It is claimed that port supply chain integration (PSCI), thanks to its attributes, holds a potential to trigger a port to strategically sustain performance- and…
Abstract
Purpose
It is claimed that port supply chain integration (PSCI), thanks to its attributes, holds a potential to trigger a port to strategically sustain performance- and competitiveness-measures through strengthening and/or reinforcing an array of port sustainability aspects. This paper aims to empirically investigate the existent influence of PSCI on economic and environmental pillars of port sustainability.
Design/methodology/approach
Based on a resource-based view, this paper hypothesises that PSCI has a certain impact on port “economic” sustainability (PECS) and port “environmental” sustainability (PENS). Measures of PSCI, PECS and PENS are refined and validated using data collected from the maritime logistics industry in Egypt, and structural equation modelling is employed to test the hypothetical relationships.
Findings
The results indicate that a port having adopted an integrative strategy into supply chains could enhance its cost and operational efficiency, financial and investment situation, while offering high-quality services to its customers. Similarly, PSCI is emphatically correlated with water and air pollution management, energy efficiency and green port management practices.
Research limitations/implications
Having identified the acute potential of PSCI for sustainable development in maritime logistics and supply chains, this line of research allows port operators and/or authorities to better understand strategic options with which they are able to improve their sustainability practices. This paper is, however, limited only to two dimensions of sustainability by not exploring the “social” aspect of port sustainability due to data-related issues.
Originality/value
This line of research could be regarded as an extended application from other industrial sectors to the port industry in a way to empirically examine the inclusive relationship of PSCI with economic and environmental parameters. The findings from this research make a due contribution to the field of port sustainability in general and Egyptian ports in particular.
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Alexandros M. Goulielmos, Venus Y. H. Lun and Kee-Hung Lai
To examine the EU ‘Short Sea Shipping’ (SSS), its ‘motorways of the sea (MoS)’ and green ports, within short sea maritime logistics.To present past research and report recent…
Abstract
To examine the EU ‘Short Sea Shipping’ (SSS), its ‘motorways of the sea (MoS)’ and green ports, within short sea maritime logistics.
To present past research and report recent developments speculating on future trends.
The dominance of SSS over road is questioned; as road transport has expanded, hubs are expected to become larger and fewer with feeders. Road transport is not certain to follow SSS and its four motorways. This result was responsible for the relocation of industry from West to East and North–East inter-port competition.
The SSS ship size and port are undefined; specific data on these concepts are unavailable.
‘Door-to-door’ services are highly sought after in this sector, but difficult to establish.
The green element introduced here, mainly for ports, will dominate future discussions because of the high importance given to climate change.
This chapter outlines for the first time the development of the policy on EU Eco-ports, the relocation of industry, the West–East port competition, the MoS and the long-term deterioration of SSS logistics which is likely to persist in the future.
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Abstract
Purpose
The maintenance of the air–water interface is crucial for the drag reduction on hydrophobic surfaces. But the air bubbles become unstable and even washed away under high speed flow, causing the failure of surface hydrophobicity. Thereby, this paper aims to understand the relations between bubble behaviors and surface properties, flow conditions and to discover new methods to maintain the air–water interface.
Design/methodology/approach
Bubble properties on hydrophobic surfaces were characterized using single-component multiphase lattice Boltzmann simulation. Three equations of state (EOSs), including the Peng–Robinson, Carnahan–Starling and modified Kaplun–Meshalkin EOSs, were incorporated to achieve high density ratios.
Findings
Both the static and dynamic properties of bubbles on hydrophobic surfaces were investigated and analyzed under different flow conditions, solid–liquid interactions and surface topology.
Originality/value
By revealing the properties of bubbles on hydrophobic surfaces, the effects of flow conditions and surface properties were characterized. The maintenance method of air–water interface can be proposed according to the bubble properties in the study.
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Yanfei Yang, Xiaobo Wang, Sen Mei, Xing Zhu, Shiqiang Chen, Peng Xiong, Zhihai Hu, Kun Xiong and Dong Song Yuan
The purpose of this paper is to investigate the tribological performance and mechanisms of BN/calcium borate nanocomposites (BCBNs) as additives in lubricating oil.
Abstract
Purpose
The purpose of this paper is to investigate the tribological performance and mechanisms of BN/calcium borate nanocomposites (BCBNs) as additives in lubricating oil.
Design/methodology/approach
BCBNs were prepared by heterogeneous deposition method. And the morphology and structure of samples were analysed by transmission electron microscopy, Fourier transform infrared spectra and X-ray powder diffraction pattern. The maximum non-seizure load (PB) of samples was tested using four-ball friction tester. The average friction coefficients and wear tracks were obtained. In addition, tribological mechanism was also investigated using optical microscope, energy dispersive spectroscopy and X-ray photoelectron spectroscope.
Findings
It was found that the nanocomposites present core-shell nanostructure with the thickness of shell around 12 nm and the diameter of particles 100-200 nm, and tribological tests indicate that the PB value of BCBNs was increased by 113 per cent, whereas the average friction coefficient was decreased by 23.6 per cent and the bloom’s wear area was also decreased by 25.2 per cent.
Originality/value
This paper involves investigation on tribological properties and mechanism of the BCBNs with core-shell structure.
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Abstract
Purpose
The paper aims to propose a stability analysis method based on region-of-attraction (ROA) overlapping to evaluate the flight stability of the possible sudden damage process and guarantee flight safety in extreme cases.
Design/methodology/approach
First, according to the two flight conditions before and after damage which the aircraft may encounter, flight dynamical models are built and fitted by polynomial equation for subsequent ROA analysis. And then, the ROA overlapping estimation method based on V-s iteration is presented to complete the stability analysis of such airplane sudden damage process.
Findings
Finally, in the presence of control surface damage, case aircraft flight stability is analyzed and simulated to verify the effectiveness of the proposed method.
Practical implications
The proposed method can be used for stability check during the aircraft control law design, or for further completing the design of the emergency stable controller design.
Originality/value
Compared with previous studies on sudden damage process of aircraft, to the best of the authors’ knowledge, this is one of the pioneer studies in which the ROA and ROA overlapping concept has been introduced. This study on stability analysis of aircraft sudden damage process could further develop the theory of emergency stable control.