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Book part
Publication date: 14 December 2018

Achim I. Czerny, Xiaowen Fu, Guowei Hua, Zheng Lei and Kun Wang

The five countries in Central Asia, namely Uzbekistan, Kazakhstan, Turkmenistan, Tajikistan, and Kyrgyzstan, are landlocked and therefore rely critically on aviation for…

Abstract

The five countries in Central Asia, namely Uzbekistan, Kazakhstan, Turkmenistan, Tajikistan, and Kyrgyzstan, are landlocked and therefore rely critically on aviation for passenger travel and express cargo logistics. However, despite substantial growth in the past decade, the aviation market in the region is still not realizing its full potential. This chapter reviews the development status of the international air travel market from Central Asia, with an aim of identifying the key barriers for industrial development and growth, and possible remedies to address these challenges. Overall, our study suggests that international market growth from the region is significantly influenced by historical patterns and political ties with Russia. Whereas markets linking selected countries such as Turkey and the UAE have experienced substantial growth, further liberalization is needed for the region to achieve better connectivity with major trade partners and aviation markets.

Details

Airline Economics in Asia
Type: Book
ISBN: 978-1-78754-566-3

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Article
Publication date: 12 October 2015

Ming Zhu, QiMing Wang, Lei Yang, Zheng Lei, Yong Wang and Mingchang Wu

Three test platforms for long-term continuous loading are adopted to test the actuator prototypes of the 500-meter aperture spherical radio telescope (FAST). However, the…

Abstract

Purpose

Three test platforms for long-term continuous loading are adopted to test the actuator prototypes of the 500-meter aperture spherical radio telescope (FAST). However, the wire ropes that are the key components of these platforms often break during testing. The purpose of this paper is to present an effective dimension design method for these wire ropes. This method is based on fatigue reliability theory.

Design/methodology/approach

Three types of stresses are introduced into the total stress model of the wire rope according to the complicated stress conditions. The fatigue strength of the ropes is also discussed in this paper. Then, the total stress model and the results of fatigue strength analysis are applied to set the optimization function for these wire ropes. Subsequently, this optimization function is used to calculate the reliability of previously developed wire ropes in relation to the actuator test platform.

Findings

The wire rope is unreliable, which is a finding that corresponds to those of previous tests. Upon drawing the optimal curve from the optimization function (whose optimal objective is the wire diameter), a wire rope is optimized for the FAST actuator test platforms. Finally, this optimized rope is used on the new actuator test platform. No fracture phenomenon has been detected in tests conducted over the past six months.

Originality/value

The fatigue reliability theory-based optimization function for wire ropes can be adopted for the universal dimension design of other wire ropes.

Details

Multidiscipline Modeling in Materials and Structures, vol. 11 no. 3
Type: Research Article
ISSN: 1573-6105

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Book part
Publication date: 14 December 2018

Xiaowen Fu and James Peoples

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Article
Publication date: 4 February 2014

Huan Chen, Junhui Jiang, Tianhui Ren, Lei Zheng and Yidong Zhao

In order to meet the requests of exploring environmental-friendly and multifunctional lubricant additives, some novel dimercaptothiadiazole derivatives containing hydroxyl…

Abstract

Purpose

In order to meet the requests of exploring environmental-friendly and multifunctional lubricant additives, some novel dimercaptothiadiazole derivatives containing hydroxyl are prepared and used as antiwear (AW) and extreme-pressure (EP) additives in biodegradable lithium grease. The paper aims to discuss these issues.

Design/methodology/approach

The tribological performances of the grease samples containing these derivatives are evaluated by using a four-ball tester. X-ray absorption near edge structure (XANES) spectroscopy is used to analyze the chemistry of tribofilms under AW/EP regime, and thermal films are also considered for comparison.

Findings

The tribological tests show that these derivatives are all effective in reducing wear, especially at lower additive concentrations, but they are basically failed in reducing friction. They are also helpful in improving the EP characteristic of the base grease. The thermal films generated by these derivatives are composed of adsorbed organic sulfide and ferrous sulfate, though for short-chain derivatives, organic sulfide is the only component at 5.0 wt.%. Ferrous sulfide is the main component of the tribofilms formed by these derivatives at various additive concentrations. But for short-chain derivatives, these tribofilms consist of ferrous sulfide and ferrous disulfide at 5.0 wt.%, and the appearance of disulfide suggests that the interfacial temperature between the upper ball and three lower balls under these conditions is considerably low. The EP films generated by short-chain derivatives are all composed of organic sulfide and ferrous sulfide, while for long-chain derivatives, ferrous sulfide is the main component.

Originality/value

These low-toxic and oil-soluble dimercaptothiadiazole derivatives are effective in improving the tribological characteristic of the biodegradable lithium grease, and these heterocyclic derivatives may be good substitutes for some harmful traditional additives.

Details

Industrial Lubrication and Tribology, vol. 66 no. 1
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 2 September 2019

Guijiang Duan, Zhibang Shen and Rui Liu

This paper aims to promote the integration of the relative position accuracy (RPA) measurement and evaluation in digital assembly process by adopting the model-based…

Abstract

Purpose

This paper aims to promote the integration of the relative position accuracy (RPA) measurement and evaluation in digital assembly process by adopting the model-based method. An integrated framework for RPA measurement is proposed based on a model-based definition (MBD) data set. The study also aims to promote the efficiency of inspection planning of RPA measurement by improving the reusability and configurability of the inspection planning.

Design/methodology/approach

The works have been carried out on three layers. In the data layer, an extended MBD data set is constructed to describe the objects and data for defining RPA measurement items; In definition layer, a model based and hierarchical structure for RPA item definition is constructed to support quick definition for RPA measurement items. In function layer, a toolset consisting three modules is constructed in a sequence from measurement planning to RPA value solving to visualized displaying again. Based on this framework, a prototype system is developed.

Findings

The paper provides an identified practice of model-based inspection. It suggests that MBD is valuable in promoting both the integration and efficiency of digital inspection.

Research limitations/implications

The templates and constructed geometry objects given in this paper are still limited in a scenario of aircraft assembly. The integrity and universality of them still need follow-up works.

Practical implications

The paper includes implications for the model based digital inspection, the digital assembly and the extended application of MBD.

Originality/value

This paper expands the application of MBD in inspection and fulfils the need to promote the integration and efficiency of digital inspection in large-scale component assembly.

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Article
Publication date: 4 June 2018

Hang Zhu, Pengxiang Zhang, Xiaoyan Han and Ting Huang

The purpose of this paper is to unveil how family involvement in management teams of private Chinese companies affects professional managers’ psychological ownership and…

Abstract

Purpose

The purpose of this paper is to unveil how family involvement in management teams of private Chinese companies affects professional managers’ psychological ownership and sense of “us”, in the hopes of understanding why their devotion cannot coexist with the higher level of commitment of family managers.

Design/methodology/approach

This paper includes two main studies. The first uses regression to analyze survey data provided by 165 professional managers working in Chinese private companies. The second is a scenario experiment in which 106 MBA candidates participate.

Findings

The study finds that there is a negative relationship between family management involvement and professional managers’ perceived relationship closeness to owners and psychological ownership of firms. It also finds that relationship closeness fully mediates the negative influence of family management involvement on managers’ psychological ownership.

Originality/value

This paper contributes to both the theoretical literature and management practice. From a theoretical perspective, it connects studies in indigenous sociological psychology with new literature on psychological ownership. The paper finds that personal relationships nurture the shared psychological ownership of managers by generating a sense of “us”, providing a new theoretical explanation for its formation process. Furthermore, this study offers an explanation for the negative signal effect of family involvement in management. From a practical perspective, this study finds that family involvement in management acts as a critical boundary condition for using personal relationships to stimulate professional managers.

Details

Nankai Business Review International, vol. 9 no. 2
Type: Research Article
ISSN: 2040-8749

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Article
Publication date: 3 September 2018

Shuanggao Li, Zhengping Deng, Qi Zeng and Xiang Huang

The assembly of large component in out-field is an important part for the usage and maintenance of aircrafts, which is mostly manually accomplished at present, as the…

Abstract

Purpose

The assembly of large component in out-field is an important part for the usage and maintenance of aircrafts, which is mostly manually accomplished at present, as the commonly used large-volume measurement systems are usually inapplicable. This paper aims to propose a novel coaxial alignment method for large aircraft component assembly using distributed monocular vision.

Design/methodology/approach

For each of the mating holes on the components, a monocular vision module is applied to measure the poses of holes, which together shape a distributed monocular vision system. A new unconstrained hole pose optimization model is developed considering the complicated wearing on hole edges, and it is solved by a iterative reweighted particle swarm optimization (IR-PSO) method. Based on the obtained poses of holes, a Plücker line coordinates-based method is proposed for the relative posture evaluation between the components, and the analytical solution of posture parameters is derived. The required movements for coaxial alignment are finally calculated using the kinematics model of parallel mechanism.

Findings

The IR-PSO method derived more accurate hole pose arguments than the state-of-the-art method under complicated wearing situation of holes, and is much more efficient due to the elimination of constraints. The accuracy of the Plücker line coordinates-based relative posture evaluation (PRPE) method is competitive with the singular value decomposition (SVD) method, but it does not rely on the corresponding of point set; thus, it is more appropriate for coaxial alignment.

Practical implications

An automatic coaxial alignment system (ACAS) has been developed for the assembly of a large pilotless aircraft, and a coaxial error of 0.04 mm is realized.

Originality/value

The IR-PSO method can be applied for pose optimization of other cylindrical object, and the analytical solution of Plücker line coordinates-based axes registration is derived for the first time.

Details

Assembly Automation, vol. 38 no. 4
Type: Research Article
ISSN: 0144-5154

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Article
Publication date: 4 December 2020

Shiqi Li, Dong Chen and Junfeng Wang

This paper aims to present a method of optimal singularity-free motion planning under multiple objectives and multiple constrains for the 6-DOF parallel manipulator, which…

Abstract

Purpose

This paper aims to present a method of optimal singularity-free motion planning under multiple objectives and multiple constrains for the 6-DOF parallel manipulator, which is used as an execution mechanism for the automated docking of components.

Design/methodology/approach

First, the distribution characteristics of the Jacobian matrix determinant in local workspace are studied based on the kinematics and a sufficient and necessary condition of singularity-free path planning in local workspace is proposed. Then, a singularity-free motion path of the end-effector is generated by a fifth-order B-spline curve and the corresponding trajectories of each actuator are obtained via the inverse kinematics. Finally, several objective functions are defined to evaluate the motion path and an improved multi-objective particle swarm optimization algorithm-based on the Pareto archive evolution is developed to obtain the optimal singularity-free motion trajectories.

Findings

If the initial pose and the target pose of the end-effector are both singularity-free, a singularity-free motion path can be planned in the local workspace as long as all the values of each pose elements in their own directions are monotonous. The improved multi-objective particle swarm optimization (IMPSO) algorithm is effective and efficient in the optimization of multi-objective motion planning model. The optimal singularity-free motion path of the end-effector is verified in the component docking test. The docking result is that the movable component is in alignment with the fixed one, which proves the feasibility and practicability of the proposed motion path method to some extent.

Originality/value

The proposed method has a certain novelty value in kinematic multi-objective motion planning of parallel manipulators; it also increases the application prospect of parallel manipulators and provides attractive solutions to component assembly for those organizations with limited cost and that want to find an option that is effective to be implemented.

Details

Industrial Robot: the international journal of robotics research and application, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0143-991X

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Book part
Publication date: 14 December 2018

Abstract

Details

Airline Economics in Asia
Type: Book
ISBN: 978-1-78754-566-3

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Article
Publication date: 25 September 2019

Hui Yuen Peng and Fong Kwong Yam

In general, lighting application, white light emitting diode (LED) usually exposed to an extreme operating temperature of above 90°C. It is well-known that luminous…

Abstract

Purpose

In general, lighting application, white light emitting diode (LED) usually exposed to an extreme operating temperature of above 90°C. It is well-known that luminous efficacy and spectral characteristic of white LED are dependent on the temperature, causing thermal effects on luminous efficacy and color shift of white LED become a critical application checkpoint to be addressed by white LED manufactures. Thus, the purpose of this paper is to minimize the thermal stability issue affecting white LED luminescence during operation by introducing phosphor sedimentation process.

Design/methodology/approach

The LED samples were assembled and sent for centrifugation with 0, 5 and 10 revolutions per second (rps), respectively, during phosphor sedimentation process. Luminescence properties of these LED samples were then characterized at a varying temperature to investigate the effect of phosphor sedimentation on the luminescence stability of LED samples. The LED samples were also cross-sectioned and analyzed to understand the phosphor sedimentation mechanism. Computational fluid dynamics (CFD) was applied to study the temperature distribution of the non-phosphor sediment (NPS) and phosphor sediment (PS) LED during operation to validate the hypotheses based on experimental data.

Findings

Experimental results show that the luminous intensity of PS LED samples degrades less significant at high temperature. The experimental results also show that the color coordinate for PS LED samples is more stable and is less blue-shifted than NPS LED samples as the temperature increased. These are because the heat generated by phosphor particles during operation can be dissipated effectively throughout a high thermal conductivity substrate after phosphor sedimentation. Thus, the phosphor temperature of PS LED is lower than NPS LED during operation as validated with the thermal simulation.

Practical implications

The study of this paper is applicable as a reference for industries who intend to resolve the thermal stability of white LED during operation. The luminescence properties changes as a function of the temperature study in this paper can be used to predict the application performances of white LED accurately. Apart from that, the analysis method of temperature distribution using CFD simulations can be extended by other CFD users in the future.

Originality/value

Implementation of phosphor sedimentation to reduce thermal instability issue of white LED has yet to be reported on previous studies. Most literature just studied the thermal instability issue of either assembled LED or raw material, without suggesting any solution to tackle the issue.

Details

Microelectronics International, vol. 37 no. 1
Type: Research Article
ISSN: 1356-5362

Keywords

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