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Article
Publication date: 2 January 2018

Hamza Hassn Alsalla, Christopher Smith and Liang Hao

The purpose of this paper is to investigate the density, surface quality, microstructure and mechanical properties of the components of the selective laser melting (SLM…

Abstract

Purpose

The purpose of this paper is to investigate the density, surface quality, microstructure and mechanical properties of the components of the selective laser melting (SLM) parts made at different building orientations. SLM is an additive manufacturing technique for three-dimensional parts. The process parameters are known to affect the properties of the eventual part. In this study, process parameters were investigated in the building of 316L structures at a variety of building orientations and for which the fracture toughness was measured.

Design/methodology/approach

Hardness and tensile tests were carried out to evaluate the effect of consolidation on the mechanical performance of specimens. Optical and electron microscopy were used to characterise the microstructure of the SLM specimens and their effects on properties relating to fracture and the mechanics. It was found that the density of built samples is 96 per cent, and the hardness is similar in comparison to conventional material.

Findings

The highest fracture toughness value was found to be 176 MPa m^(1/2) in the oz. building direction, and the lowest value was 145 MPa m^(1/2) in the z building direction. This was due to pores and some cracks at the edge, which are slightly lower in comparison to a conventional product. The build direction does have an effect on the microstructure of parts, which subsequently has an effect upon their mechanical properties and surface quality. Dendritic grain structures were found in oz. samples due to the high temperature gradient, fast cooling rate and reduced porosity. The tensile properties of such parts were found to be better than those made from conventional material.

Originality/value

The relationship between the process parameters, microstructure, surface quality and toughness has not previously been reported.

Details

Rapid Prototyping Journal, vol. 24 no. 1
Type: Research Article
ISSN: 1355-2546

Keywords

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Article
Publication date: 12 March 2018

Hamza Hassn Alsalla, Christopher Smith and Liang Hao

The purpose of this paper is to study new process parameters which were selected to achieve the full density of Ti-6Al-4V samples in different building orientations and…

Abstract

Purpose

The purpose of this paper is to study new process parameters which were selected to achieve the full density of Ti-6Al-4V samples in different building orientations and investigate fracture toughness property and its relation to the microstructure, an area which has not previously been reported in full detail and which may offer information to a designer. Direct metal laser sintering (DMLS) is an additive manufacturing technique that directly manufactures three-dimensional parts, layer-by-layer, to scan and melt metal powders for aerospace applications.

Design/methodology/approach

Hardness and tensile tests were carried out to evaluate the effect of consolidation on the mechanical performance of specimens made at three different building directions. Optical and electron microscopy were used to characterise the microstructure of the DMLS specimens and their effects on the fractures and mechanical properties.

Findings

It was found that the built samples have an excellent density at 4.5 g/cm, and the sample surfaces parallel to the building direction are rougher than the perpendicular surfaces. The fracture toughness result was higher than that of the cast material for the same alloy and higher than the Ti-6Al-4V parts fabricated by electron beam melting. This results in the superior mechanical properties of DMLS, while slightly lower in the zy direction owing to cracks, porosity and surface finish.

Research limitations/implications

The tensile strength was found to be higher than the wrought material, and the samples exhibited brittle fractures owing to the martensitic phase, which is caused by a high temperature gradient, and the mechanical properties change with the change in the microstructures at different building directions.

Originality/value

This paper contains original research.

Details

Rapid Prototyping Journal, vol. 24 no. 2
Type: Research Article
ISSN: 1355-2546

Keywords

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Article
Publication date: 1 June 2021

Yushen Wang, Wei Xiong, Danna Tang, Liang Hao, Zheng Li, Yan Li and Kaka Cheng

Traditional simulation research of geological and similar engineering models, such as landslides or other natural disaster scenarios, usually focuses on the change of…

Abstract

Purpose

Traditional simulation research of geological and similar engineering models, such as landslides or other natural disaster scenarios, usually focuses on the change of stress and the state of the model before and after destruction. However, the transition of the inner change is usually invisible. To optimize and make models more intelligent, this paper aims to propose a perceptible design to detect the internal temperature change transformed by other energy versions like stress or torsion.

Design/methodology/approach

In this paper, micron diamond particles were embedded in 3D printed geopolymers as a potential thermal sensor material to detect the inner heat change. The authors use synthetic micron diamond powder to reinforced the anti-corrosion properties and thermal conductivity of geopolymer and apply this novel geopolymer slurry in the direct ink writing (DIW) technique.

Findings

As a result, the addition of micron diamond powder can greatly influence the rheology of geopolymer slurry and make the geopolymer slurry extrudable and suitable for DIW by reducing the slope of the viscosity of this inorganic colloid. The heat transfer coefficient of the micron diamond (15 Wt.%)/geopolymer was 50% higher than the pure geopolymer, which could be detected by the infrared thermal imager. Besides, the addition of diamond particles also increased the porous rates of geopolymer.

Originality/value

In conclusion, DIW slurry deposition of micron diamond-embedded geopolymer (MDG) composites could be used to manufacture the multi-functional geological model for thermal imaging and defect detection, which need the characteristic of lightweight, isolation, heat transfer and wave absorption.

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Article
Publication date: 29 August 2019

Danna Tang, Liang Hao, Yan Li and Zheng Li

The study aims to explore the composition and microstructure of clay functionally graded materials under the process of double-gradient direct ink writing (DIW).

Abstract

Purpose

The study aims to explore the composition and microstructure of clay functionally graded materials under the process of double-gradient direct ink writing (DIW).

Design/methodology/approach

The investigation focused specifically on the pore characteristics of barite-kaolin clay composite after three-dimensional (3D) printing and sintering as well as its bionic application in geophysical model.

Findings

The model with pore and material variations brought about spatial and nonlinear mechanical properties. Moreover, the vertical gradient and connected pores in the upper kaolin part simulated the natural phenomenon of the landslide model (take Chinese Majiagou landslides as an example). Both the thermal debinding behavior and the kaolin powder particles characteristics [large pore volume (0.019 cm3g1) and pore size (29.20 nm)] were attributed to the interconnection channels.

Originality/value

Hence, the macroscopic and microscopic pores achieved by dual-gradient DIW process make it possible to control the permeability and details of properties, precisely in the geological model.

Details

Rapid Prototyping Journal, vol. 26 no. 1
Type: Research Article
ISSN: 1355-2546

Keywords

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Article
Publication date: 22 June 2021

Wee Kheng Tan and Hao-Jen Liang

To alleviate the effects of coronavirus disease 2019 (COVID-19) on the economy, Taiwan introduced a stimulus package in the form of triple stimulus vouchers. Despite…

Abstract

Purpose

To alleviate the effects of coronavirus disease 2019 (COVID-19) on the economy, Taiwan introduced a stimulus package in the form of triple stimulus vouchers. Despite intense promotion to opt for the vouchers in digital form, Taiwanese public overwhelmingly chose the paper form. This study considers the reasons that influenced their decision comfort in choosing paper rather than digital vouchers based on two categories: rational (promotion depth and ease of use) and behavioral economics factors (analysis paralysis, mental accounting related to ease of tracking expenses, social influence and payment habits).

Design/methodology/approach

Partial least squares (PLS) method was utilized to analyze survey information obtained from 183 individuals who chose paper vouchers.

Findings

Individuals consider rational and behavioral economic factors in their perception of decision comfort while choosing paper over digital vouchers. Decision comfort is driven more by behavioral economics than rational factors such as ease of use. Interestingly, analysis paralysis related to paper vouchers has the greatest impact, but it positively influences decision comfort, indicating that Taiwanese people view paper vouchers as a safe haven in the midst of uncertainties and information overload. Therefore, when designing public policies or promotional campaigns, possible behavior outcomes should be considered from both rational and behavioral economic perspectives.

Originality/value

This study provides insights into the dynamics of how individuals arrive at their decision of opting paper vouchers over digital ones and offers theoretical contributions related to system adoption and behavioral economics.

Details

Asia Pacific Journal of Marketing and Logistics, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1355-5855

Keywords

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Book part
Publication date: 12 November 2016

Hao Liang, Luc Renneboog and Sunny Li Sun

We take a state-stewardship view on corporate governance and executive compensation in economies with strong political involvement, where state-appointed managers act as…

Abstract

Purpose

We take a state-stewardship view on corporate governance and executive compensation in economies with strong political involvement, where state-appointed managers act as responsible “stewards” rather than “agents” of the state.

Methodology/approach

We test this view on China and find that Chinese managers are remunerated not for maximizing equity value but for increasing the value of state-owned assets.

Findings

Managerial compensation depends on political connections and prestige, and on the firms’ contribution to political goals. These effects were attenuated since the market-oriented governance reform.

Research limitations/implications

Economic reform without reforming the human resources policies at the executive level enables the autocratic state to exert political power on corporate decision making, so as to ensure that firms’ business activities fulfill the state’s political objectives.

Practical implications

As a powerful social elite, the state-steward managers in China have the same interests as the state (the government), namely extracting rents that should adhere to the nation (which stands for the society at large or the collective private citizens).

Social implications

As China has been a communist country with a single ruling party for decades, the ideas of socialism still have a strong impact on how companies are run. The legitimacy of the elite’s privileged rights over private sectors is central to our question.

Originality/value

Chinese executive compensation stimulates not only the maximization of shareholder value but also the preservation of the state’s interests.

Details

The Political Economy of Chinese Finance
Type: Book
ISBN: 978-1-78560-957-2

Keywords

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Article
Publication date: 16 January 2007

Chang Jiang Yang, Cheng Hao Liang and Xia Liu

This paper seeks to investigate work on silver sulphide formed on the surface of silver metal which was exposed to an environment containing sulphur contamination.

Abstract

Purpose

This paper seeks to investigate work on silver sulphide formed on the surface of silver metal which was exposed to an environment containing sulphur contamination.

Design/methodology/approach

Laboratory tests were performed to determine the effect of the surface state, relative humidity, temperature and illumination.

Findings

It was indicated that sulphuration of silver was accelerated by mechanical polishing and illumination. The exposure was performed at 0, 54, 75 per cent relative humidity (rH) and at 16, 25, 37, 47 and 57°C. The tarnish rate at 54 per cent rH was more than two times than that at 0 per cent rH or 75 per cent rH, and the rate increased as a function of temperature.

Originality/value

A tarnish model was proposed. The tarnish reaction of silver is chemical reaction controlled, which is in accordance with the result deduced from the model.

Details

Anti-Corrosion Methods and Materials, vol. 54 no. 1
Type: Research Article
ISSN: 0003-5599

Keywords

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Article
Publication date: 19 November 2003

Fengru Li and Nader H. Shooshtari

Applying brand names to international markets remains a challenge to multinational corporations. Consumers’ sociolinguistic backgrounds shape their responses to brand…

Abstract

Applying brand names to international markets remains a challenge to multinational corporations. Consumers’ sociolinguistic backgrounds shape their responses to brand names. This paper uses a sociolinguistic approach as a conceptual framework in understanding brand naming and translating in the Chinese market. The approach promotes that sociolinguistics a) recognizes linguistic competence, b) advances symbolic values imbedded in linguistic forms, and c) renders attached social valence to cultural scrutiny. Three brand‐naming cases in China are presented for discussion, which may benefit multinational corporations on brand decisions involving Chinese consumers.

Details

Multinational Business Review, vol. 11 no. 3
Type: Research Article
ISSN: 1525-383X

Keywords

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Article
Publication date: 7 March 2008

Wei‐Xin Ren, HaoLiang Liu and Gang Chen

Owing to the cable flexibility, it is practically a lot easier to measure the high‐vibration frequencies of the cable than the fundamental vibration frequency. The…

Abstract

Purpose

Owing to the cable flexibility, it is practically a lot easier to measure the high‐vibration frequencies of the cable than the fundamental vibration frequency. The objective of this study is to present a method to determine the cable tension based on frequency differences so that the effects of cable sag and bending stiffness can be included.

Design/methodology/approach

The paper includes theoretical derivation, laboratory study to verify the method and practical application in a real bridge.

Findings

It is suggested to measure the high‐vibration frequencies, and to use the vibration frequency difference to determine the fundamental vibration frequency of the cable and then to estimate the cable tension. The reliability of the method is verified by laboratory tests and the method is then applied to determine cable tensions in a real bridge.

Originality/value

This paper provides theoretical derivations to demonstrate that under certain conditions, the frequency difference of a cable with sag and bending is almost equal to the natural frequency of the same cable when it is taut. This unique characteristic of cable vibration is used to determine the cable tension similar to the fundamental frequency‐based taut‐string formula that is commonly used in practice.

Details

Engineering Computations, vol. 25 no. 2
Type: Research Article
ISSN: 0264-4401

Keywords

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Book part
Publication date: 12 November 2016

Abstract

Details

The Political Economy of Chinese Finance
Type: Book
ISBN: 978-1-78560-957-2

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