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Article
Publication date: 29 August 2019

Wei Du, Lei Luo, Songtao Wang, Jian Liu and Bengt Ake Sunden

The purpose of this study is to enhance the thermal performance in the labyrinth channel by different ribs shape. The labyrinth channel is a relatively new cooling…

Abstract

Purpose

The purpose of this study is to enhance the thermal performance in the labyrinth channel by different ribs shape. The labyrinth channel is a relatively new cooling structure to decrease the temperature near the trailing region of gas turbine.

Design/methodology/approach

Based on the geometric similarity, a simplified geometric model is used. The k − ω turbulence model is used to close the Navier–Stokes equations. Five rib shapes (one rectangular rib, two arched ribs and two trapezoid ribs) and five Reynolds numbers (10,000 to 50,000) are considered. The Nusselt number, flow structure and friction factor are analyzed.

Findings

Nusselt number is tightly related to the rib shape in the labyrinth channel. The different shapes of the ribs result in different horseshoe vortex and wake region. In general, the arched rib brings the highest Nusselt number and friction factor. The Nusselt number is increased by 15.8 per cent compared to that of trapezoidal ribs. High Nusselt number is accompanied by the high friction factor in a labyrinth channels. The friction factor is increased by 64.6 per cent compared to rectangular ribs. However, the rib shape has a minor effect on the overall thermal performance.

Practical implications

This study is useful to protect the trailing region of advanced gas turbine.

Originality/value

This paper presents the flow structure and heat transfer characteristics in a labyrinth channel with different rib shapes.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 30 no. 2
Type: Research Article
ISSN: 0961-5539

Keywords

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Book part
Publication date: 23 September 2019

Yi-Ming Wei, Qiao-Mei Liang, Gang Wu and Hua Liao

Abstract

Details

Energy Economics
Type: Book
ISBN: 978-1-83867-294-2

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Article
Publication date: 11 June 2021

Wei Du, Qiang Yan, Wenping Zhang and Jian Ma

Patent trade recommendations necessitate recommendation interpretability in addition to recommendation accuracy because of patent transaction risks and the technological…

Abstract

Purpose

Patent trade recommendations necessitate recommendation interpretability in addition to recommendation accuracy because of patent transaction risks and the technological complexity of patents. This study designs an interpretable knowledge-aware patent recommendation model (IKPRM) for patent trading. IKPRM first creates a patent knowledge graph (PKG) for patent trade recommendations and then leverages paths in the PKG to achieve recommendation interpretability.

Design/methodology/approach

First, we construct a PKG to integrate online company behaviors and patent information using natural language processing techniques. Second, a bidirectional long short-term memory network (BiLSTM) is utilized with an attention mechanism to establish the connecting paths of a company — patent pair in PKG. Finally, the prediction score of a company — patent pair is calculated by assigning different weights to their connecting paths. The semantic relationships in connecting paths help explain why a candidate patent is recommended.

Findings

Experiments on a real dataset from a patent trading platform verify that IKPRM significantly outperforms baseline methods in terms of hit ratio and normalized discounted cumulative gain (nDCG). The analysis of an online user study verified the interpretability of our recommendations.

Originality/value

A meta-path-based recommendation can achieve certain explainability but suffers from low flexibility when reasoning on heterogeneous information. To bridge this gap, we propose the IKPRM to explain the full paths in the knowledge graph. IKPRM demonstrates good performance and transparency and is a solid foundation for integrating interpretable artificial intelligence into complex tasks such as intelligent recommendations.

Details

Internet Research, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1066-2243

Keywords

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Article
Publication date: 11 October 2018

Lei Luo, Wei Du, Songtao Wang, Weilong Wu and Xinghong Zhang

The purpose of this paper is to investigate the optimal geometry parameters in a dimple/protrusion-pin finned channel with high thermal performance.

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Abstract

Purpose

The purpose of this paper is to investigate the optimal geometry parameters in a dimple/protrusion-pin finned channel with high thermal performance.

Design/methodology/approach

The BSL turbulence model is used to calculate the flow structure and heat transfer in a dimple/protrusion-pin finned channel. The optimization algorithm is set as Non-dominated Sorting Genetic Algorithm II (NSGA-II). The high Nusselt number and low friction factor are chosen as the optimization objectives. The pin fin diameter, dimple/protrusion diameter, dimple/protrusion location and dimple/protrusion depth are applied as the optimization variables. An in-house code is used to generate the geometry model and mesh. The commercial software Isight is used to perform the optimization process.

Findings

The results show that the Nusselt number and friction factor are sensitive to the geometry parameters. In a pin finned channel with a dimple, the Nusselt number is high at the rear part of the dimple, while it is low at the upstream of the dimple. A high dissipative function is found near the pin fin. In the protrusion channel, the Nusselt number is high at the leading edge of the protrusion. In addition, the protrusion induces a high pressure drop compared to the dimpled channel.

Originality/value

The originality of this paper is to optimize the geometry parameters in a pin finned channel with dimple/protrusion. This is good application for the heat transfer enhancement at the trailing side for the gas turbine.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 29 no. 2
Type: Research Article
ISSN: 0961-5539

Keywords

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Article
Publication date: 13 March 2020

Wenping Zhang, Wei Du, Yiyang Bian, Chih-Hung Peng and Qiqi Jiang

The purpose of this study is to unpack the antecedents and consequences of clickbait prevalence in online media at two different levels, namely, (1) Headline-level: what…

Abstract

Purpose

The purpose of this study is to unpack the antecedents and consequences of clickbait prevalence in online media at two different levels, namely, (1) Headline-level: what characteristics of clickbait headlines attract user clicks and (2) Publisher-level: what happens to publishers who create clickbait on a prolonged basis.

Design/methodology/approach

To test the proposed conjectures, the authors collected longitudinal data in collaboration with a leading company that operates more than 500 WeChat official accounts in China. This study proposed a text mining framework to extract and quantify clickbait rhetorical features (i.e. hyperbole, insinuation, puzzle, and visual rhetoric). Econometric analysis was employed for empirical validation.

Findings

The findings revealed that (1) hyperbole, insinuation, and visual rhetoric entice users to click the baited headlines, (2) there is an inverted U-shaped relationship between the number of clickbait headlines posted by a publisher and its visit traffic, and (3) this non-linear relationship is moderated by the publisher's age.

Research limitations/implications

This research contributes to current literature on clickbait detection and clickbait consequences. Future studies can design more sophisticated methods for extracting rhetorical characteristics and implement in different languages.

Practical implications

The findings could aid online media publishers to design attractive headlines and develop clickbait strategies to avoid user churn, and help managers enact appropriate regulations and policies to control clickbait prevalence.

Originality/value

The authors propose a novel text mining framework to quantify rhetoric embedded in clickbait. This study empirically investigates antecedents and consequences of clickbait prevalence through an exploratory study of WeChat in China.

Details

Internet Research, vol. 30 no. 3
Type: Research Article
ISSN: 1066-2243

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Article
Publication date: 28 January 2020

Haihua Wu, Junfeng Li, Zhengying Wei and Pei Wei

To fabricate a selective laser melting (SLM)-processed AlSi10Mg part with almost full density and free of any apparent pores, this study aims to investigate the effect of…

Abstract

Purpose

To fabricate a selective laser melting (SLM)-processed AlSi10Mg part with almost full density and free of any apparent pores, this study aims to investigate the effect of ambient argon pressure and laser scanning speed on the particles splash during the AlSi10Mg powder bed laser melting.

Design/methodology/approach

Based on the discrete element method (DEM), a 3D model of random distribution of powder particles was established, and the 3D free surface of SLM forming process was dynamically tracked by the volume of fluid, where a Gaussian laser beam acts as the energy source melting the powder bed. Through the numerical simulation and process experimental research, the effect of the applied laser power and scanning speed on the operating laser melting temperature was studied.

Findings

The process stability has a fundamental role in the porosity formation, which is process-dependent. The effect of the processing conditions on the process stability and the resultant forming defects were clarified.

Research limitations/implications

The results shows that the pores were the main defects present in the SLM-processed AlSi10Mg sample, which decreases the densification level of the sample.

Practical implications

The optimal processing parameters (argon pressure of 1,000 Pa, laser power of 180 W, scan speed of 1,000 mm/s, powder layer thickness of 35 µm and hatch spacing of 50 µm ) applied during laser melting can improve the quality of selective laser melting of AlSi10Mg,

Social implications

It can provide a technological support for 3D printing.

Originality/value

Based on the analysis of the pore and balling formation mechanisms, the optimal processing parameters have been obtained, which were argon pressure of 1,000 Pa, laser power of 180 W, scan speed of 1,000 mm/s, powder layer thickness of 35 µm and hatch spacing of 50 µm. Then, a near-fully dense sample free of any apparent pores on the cross-sectional microstructure was produced by SLM, wherein the relative density of the as-built samples is larger than 97.5%.

Details

Rapid Prototyping Journal, vol. 26 no. 5
Type: Research Article
ISSN: 1355-2546

Keywords

Content available
Book part
Publication date: 28 December 2016

Bhaskar Bagchi, Dhrubaranjan Dandapat and Susmita Chatterjee

Abstract

Details

Dynamic Linkages and Volatility Spillover
Type: Book
ISBN: 978-1-78635-554-6

Content available
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94

Abstract

Details

Anti-Corrosion Methods and Materials, vol. 56 no. 5
Type: Research Article
ISSN: 0003-5599

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Case study
Publication date: 1 May 2009

Lynda L. Moore and Bonita L. Betters-Reed

This case is about Kija Kim, a Korean born founder and CEO of Harvard Design and Mapping Inc. (HDM). Founded in 1988, HDM is a cutting-edge GIS firm with $5 million in…

Abstract

This case is about Kija Kim, a Korean born founder and CEO of Harvard Design and Mapping Inc. (HDM). Founded in 1988, HDM is a cutting-edge GIS firm with $5 million in revenue and 35 employees in their Cambridge, MA and Washington D.C. offices. Through Kija Kim's leadership, HDM has become a significant niche player in homeland security and disaster relief. The case ends in fall 2005 just after HDM provided Hurricane Katrina mapping support, and Kija is nominated for the SBA Small Business Person of the Year. This case explores the intersection between cultural heritage, leadership effectiveness and organizational behavior. It particularly notes Kija's ability to turn her immigrant female minority status into a business advantage. This strength coupled with her ethos of care and ability to network in all walks of her life contributes to her distinctive and integrated leadership style. Definitions of leadership success and implications for decision making are also highlighted.

Details

The CASE Journal, vol. 5 no. 2
Type: Case Study
ISSN: 1544-9106

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Article
Publication date: 29 May 2019

Feng Zhan

The purpose of this paper is to examine the impact of national culture on herding behavior across international financial markets.

Abstract

Purpose

The purpose of this paper is to examine the impact of national culture on herding behavior across international financial markets.

Design/methodology/approach

The relation between national culture and investor behavior, and how it impacts overall market volatility is studied by examining synchronized stock price movements and stock market volatility in 47 countries around the world over the period of January 2003–May 2012.

Findings

The author finds that nations with lower values of individualistic culture are more likely to have a higher number of synchronized stock price movements. Further, the correlation between stock price movements apparently increases stock market volatility. Nations with high individualistic culture have a lower number of synchronized stock price movements and, thus, have lower levels of stock market volatility. The positive relationship between synchronized stock price movements and stock market volatility is stronger for emerging markets during the financial crisis from June 2007 to December 2008.

Originality/value

The empirical results in this paper indicate that a portion of the difference in market level volatility is attributed to the investor bias of different cultures. Investor behavior bias creates excess volatility that drives stock prices away from fundamentals. This impact is strong in nations with lower individualistic culture. The result from this research could also have a wide implication in the investment industry.

Details

International Journal of Managerial Finance, vol. 15 no. 3
Type: Research Article
ISSN: 1743-9132

Keywords

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