Shijie Jiang, Mingyu Sun, Yang Zhan, Hui Li and Wei Sun
The purpose of this study is to set up a dynamic model of material extrusion (ME) additive manufacturing plates for the prediction of their dynamic behavior (i.e. dynamic inherent…
Abstract
Purpose
The purpose of this study is to set up a dynamic model of material extrusion (ME) additive manufacturing plates for the prediction of their dynamic behavior (i.e. dynamic inherent characteristic, resonant response and damping) and also carry out its experimental validation and sensitivity analysis.
Design/methodology/approach
Based on the classical laminated plate theory, a dynamic model is established using the orthogonal polynomials method, taking into account the effect of lamination and orthogonal anisotropy. The dynamic inherent characteristics of the ME plate are worked out by Ritz method. The frequency-domain dynamic equations are then derived to solve the plates’ resonant responses, with which the damping ratio is figured out according to the half-power bandwidth method. Subsequently, a series of experimental tests are performed on the ME samples to obtain the measured data.
Findings
It is shown that the predictions and measurements in terms of dynamic behavior are in good agreement, validating the accuracy of the developed model. In addition, sensitivity analysis shows that increasing the elastic modulus or Poisson’s ratio will increase the corresponding natural frequency of the ME plate but decrease the resonant response. When the density is increased, both the natural frequency and resonant response will be decreased.
Research limitations/implications
Future research can be focused on using the proposed model to investigate the effect of processing parameters on the ME parts’ dynamic behavior.
Practical implications
This study shows theoretical basis and technical insight into improving the forming quality and reliability of the ME parts.
Originality/value
A novel reliable dynamic model is set up to provide theoretical basis and principle to reveal the physical phenomena and mechanism of ME parts.
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Zengkun Zhang, Dongru Li, Jianjun Wu, Muzamil Muhammad and Yang Li
When bending a large diameter thin-walled tube, the thickn ess of outer side wall will reduce greatly, which leads to a decrease of structural strength of the tube. To solve this…
Abstract
Purpose
When bending a large diameter thin-walled tube, the thickn ess of outer side wall will reduce greatly, which leads to a decrease of structural strength of the tube. To solve this problem, this paper investigated the deformation principles of an eccentric tube in the rotary draw bending process, trying to find a way to reduce the wall thickness difference between inner and outer diameters.
Design/methodology/approach
An finite element model is established for analyzing the deformation of an eccentric tube in rotary draw bending process. The wall thickness distribution of the formed pipe was analyzed along the axis and diameter, respectively.
Findings
It is found that there exists an optimal eccentricity between the inner and outer circle center of the tube cross-section. If the eccentricity of the tube is chosen properly, it is possible to get a bent tube with equal thickness of inner and outer side walls. In addition, it is also found the optimal eccentricity on the cross-section can be influenced by bending radius, wall thickness, diameter and bending angle. The optimal eccentricity increases greatly with the decreasing of bending radius, the increase of outer diameter and the increase of wall thickness. The influence of bending angle on the optimal eccentricity can be divided into two situations. When the bending angle is small, the optimal eccentricity increases with the increase of bending angle. When the bending angle exceeds a certain value, the pipe enters a stable forming state. The optimal eccentricity of the stable forming region does not change with the bending angle.
Originality/value
Such a research is beneficial for reducing the thickness difference between inner and outer side walls in the rotary draw bending process.
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Hasan Dinçer, Serhat Yüksel, Gülsüm Sena Uluer and Çağatay Çağlayan
The aim of this study is to examine the significant factors to improve the green nuclear energy investments in the emerging economies. For this purpose, balanced scorecard-based…
Abstract
The aim of this study is to examine the significant factors to improve the green nuclear energy investments in the emerging economies. For this purpose, balanced scorecard-based criteria are weighted with DEMATEL methodology. The findings demonstrate that technological improvement and financial issues are the most important issues for the improvement of the green nuclear energy investments in these countries. Nuclear energy working with thorium can also be obtained with proton accelerator technology that is currently quite expensive. Because of this problem, the investors are not willing to make investments for green nuclear energy projects. Hence, emerging countries should make the necessary technological investments to have proton accelerator technologies. With the help of this condition, it will be possible to reduce the cost of green nuclear energy projects which attracts the attention of the investors. This situation has a powerful contribution for the sustainable economic development of these countries.
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Jaclyn Koopmann, Mo Wang, Yihao Liu and Yifan Song
In this chapter, we summarize and build on the current state of the customer mistreatment literature in an effort to further future research on this topic. First, we detail the…
Abstract
In this chapter, we summarize and build on the current state of the customer mistreatment literature in an effort to further future research on this topic. First, we detail the four primary conceptualizations of customer mistreatment. Second, we present a multilevel model of customer mistreatment, which distinguishes between the unfolding processes at the individual employee level and the service encounter level. In particular, we consider the antecedents and outcomes unique to each level of analysis as well as mediators and moderators. Finally, we discuss important methodological concerns and recommendations for future research.
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Farzana Quoquab, Maizaitulaidawati Md Husin, Rohaida Basiruddin and Abdul Hamid Mohamed
Traditional Chinese Medicine (TCM) is a complete medical healthcare system that encompasses acupuncture, acupressure, moxibustion, herbal medicine, diet, tui na massage, and…
Abstract
Traditional Chinese Medicine (TCM) is a complete medical healthcare system that encompasses acupuncture, acupressure, moxibustion, herbal medicine, diet, tui na massage, and exercises (tai chi and qigong) among other traditional therapies. It uses herbs and natural resources to produce the traditional medicines and focuses on maintaining the balance between body and mind. As such, many aspects of TCM can be considered as green and sustainable. While there is market demand for TCM in some countries and among some communities, some others are still not aware of TCM. Moreover, there are fewer discussions in the academic platforms on TCM. This case highlights the scenario of TCM based on Malaysia’s perspective and discusses its challenges and prospects.
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This paper proposes that if a political system is more like to facilitate a unified government, to establish a strong executive body and to respond to the needs of the majority…
Abstract
This paper proposes that if a political system is more like to facilitate a unified government, to establish a strong executive body and to respond to the needs of the majority, financial reforms are more likely to emerge from the policymaking process and produce positive results. On the contrary, political systems that discourage those governing features are less likely to produce reforms. This chapter compares financial reform processes in China, Taiwan and New Zealand. All of them performed low level of financial reforms in the early 1980s but resulted in different situations later. In the mid-2000s, New Zealand heralded the most efficient and stable financial system; while Taiwan lagged behind and China performed the worst. Evidence showed that China’s authoritarian system may be the most superior in forming a unified government with a strong executive, but the policy priority often responds more to the interests of a small group of power elites; therefore the result of financial reform can be limited. Taiwan’s presidential system can produce greater financial reform when the ruling party controls both executive and legislative bodies, but legislative obstructions may occur under a divided government. New Zealand's Westminster system produces the most effective and efficient financial reform due to its unified government and a strong executive branch with consistent and stable supports from the New Zealand Parliament.
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Haina Song, Shengpei Zhou, Zhenting Chang, Yuejiang Su, Xiaosong Liu and Jingfeng Yang
Autonomous driving depends on the collection, processing and analysis of environmental information and vehicle information. Environmental perception and processing are important…
Abstract
Purpose
Autonomous driving depends on the collection, processing and analysis of environmental information and vehicle information. Environmental perception and processing are important prerequisite for the safety of self-driving of vehicles; it involves road boundary detection, vehicle detection, pedestrian detection using sensors such as laser rangefinder, video camera, vehicle borne radar, etc.
Design/methodology/approach
Subjected to various environmental factors, the data clock information is often out of sync because of different data acquisition frequency, which leads to the difficulty in data fusion. In this study, according to practical requirements, a multi-sensor environmental perception collaborative method was first proposed; then, based on the principle of target priority, large-scale priority, moving target priority and difference priority, a multi-sensor data fusion optimization algorithm based on convolutional neural network was proposed.
Findings
The average unload scheduling delay of the algorithm for test data before and after optimization under different network transmission rates. It can be seen that with the improvement of network transmission rate and processing capacity, the unload scheduling delay decreased after optimization and the performance of the test results is the closest to the optimal solution indicating the excellent performance of the optimization algorithm and its adaptivity to different environments.
Originality/value
In this paper, the results showed that the proposed method significantly improved the redundancy and fault tolerance of the system thus ensuring fast and correct decision-making during driving.
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This research addressed online customer-to-customer (C2C) incivility during digital service recovery.
Abstract
Purpose
This research addressed online customer-to-customer (C2C) incivility during digital service recovery.
Design/methodology/approach
To examine the effectiveness of managerial responses to online C2C incivility post a restaurant service failure, a 2 (Managerial response: general vs specific) x 2 (Failure severity: high vs low) quasi-experimental design was employed. A pretest was conducted with 123 restaurant consumers via Amazon Mechanical Turk, followed by a main study with 174 restaurant consumers. Taking a mixed-method approach, this research first asked open-ended questions to explore how participants perceived the restaurant’s motivation for providing a generic versus a specific response. Hayes’ (2013) PROCESS procedure was then performed for hypotheses testing.
Findings
The results revealed significant interaction effects of managerial responses and failure severity on perceived online service climate and revisit intention, mediated by trust with managerial responses.
Originality/value
This research yielded unique insight into C2C incivility management literature and industry practices in the context of digital customer service recovery.
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Rong Jiang, Bin He, Zhipeng Wang, Xu Cheng, Hongrui Sang and Yanmin Zhou
Compared with traditional methods relying on manual teaching or system modeling, data-driven learning methods, such as deep reinforcement learning and imitation learning, show…
Abstract
Purpose
Compared with traditional methods relying on manual teaching or system modeling, data-driven learning methods, such as deep reinforcement learning and imitation learning, show more promising potential to cope with the challenges brought by increasingly complex tasks and environments, which have become the hot research topic in the field of robot skill learning. However, the contradiction between the difficulty of collecting robot–environment interaction data and the low data efficiency causes all these methods to face a serious data dilemma, which has become one of the key issues restricting their development. Therefore, this paper aims to comprehensively sort out and analyze the cause and solutions for the data dilemma in robot skill learning.
Design/methodology/approach
First, this review analyzes the causes of the data dilemma based on the classification and comparison of data-driven methods for robot skill learning; Then, the existing methods used to solve the data dilemma are introduced in detail. Finally, this review discusses the remaining open challenges and promising research topics for solving the data dilemma in the future.
Findings
This review shows that simulation–reality combination, state representation learning and knowledge sharing are crucial for overcoming the data dilemma of robot skill learning.
Originality/value
To the best of the authors’ knowledge, there are no surveys that systematically and comprehensively sort out and analyze the data dilemma in robot skill learning in the existing literature. It is hoped that this review can be helpful to better address the data dilemma in robot skill learning in the future.
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Chenchun Shi, Aibing Yu, Jianzhao Wu, Weiyang Niu and Yanlin Wang
The study aims to compare tribological properties between laser dimple textured surface and drilled dimple textured surface, and to analyze the influence of dimple hardened edges…
Abstract
Purpose
The study aims to compare tribological properties between laser dimple textured surface and drilled dimple textured surface, and to analyze the influence of dimple hardened edges and ability of trapping wear debris on wear properties of dimple textured surfaces.
Design/methodology/approach
Circular textured dimples were produced on AISI 1,045 specimen surfaces using laser surface texturing (LST) and drilled surface texturing (DST) methods. Tribological behaviors of LST, DST and non-textured specimens were studied using ball-on-disc tribo-tester. Metallographic structures, dimples and worn surface morphologies were observed using a three-dimensional digital microscope. Hardnesses of substrate and dimple edges were measured.
Findings
There was no obvious difference in wear and friction coefficients between LST and DST specimens. Hardnesses of laser dimple edges were much higher than that of drilled dimple edges and specimen substrate. The hardened materials of laser dimple edge included recast zone and heat affect zone. Laser dimple was cone-shaped and drilled dimple was cylinder-shaped. Drilled dimple had a better ability of trapping wear debris than laser dimple. Non-uniform wear phenomenon occurred on worn surfaces of LST dimple specimens.
Originality/value
The ability of textured dimples to trap wear debris is affected by single dimple volume. Hardened edges of dimples cause non-uniform wear on worn surfaces of LST specimens.