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Article
Publication date: 13 November 2017

Zhixiang Song, Fei Guo, Ying Liu, Songtao Hu, Xiangfeng Liu and Yuming Wang

This paper aims to present the slip/no-slip design in two-dimensional water-lubricated tilting pad thrust bearings (TPTBs) considering the turbulence effect and shifting…

Abstract

Purpose

This paper aims to present the slip/no-slip design in two-dimensional water-lubricated tilting pad thrust bearings (TPTBs) considering the turbulence effect and shifting of pressure centers.

Design/methodology/approach

A numerical model is established to analyze the slip condition and the effect of turbulence according to a Reynolds number defined in terms of the slip condition. Simulations are carried out for eccentrically and centrally pivoted bearings and the influence of different slip parameters is discussed.

Findings

A considerable enhancement in load capacity, as well as a reduction in friction, can be achieved by heterogeneous slip/no-slip surface designs for lubricated sliding contacts, especially for near parallel pad configurations. The optimized design largely depends on the pivot position. The load capacity increases by 174 per cent for eccentrically pivoted bearings and 159 per cent for centrally pivoted bearings for a suitable design. When slip zone locates at the middle of the radial direction or close to the inner edge, the performance of the TPTB is better.

Research limitations/implications

The simplification of slip effect on the turbulence (definition of Reynolds number) can only describe the trend of the increasing turbulence due to slip condition. The accurate turbulence expression considering the boundary slip needs further explorations.

Originality/value

The shifting of pressure center due to the slip/no-slip design for TPTBs is investigated in this study. The turbulence effect and influence of slip parameters is discussed for large water-lubricated bearings.

Details

Industrial Lubrication and Tribology, vol. 69 no. 6
Type: Research Article
ISSN: 0036-8792

Keywords

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Article
Publication date: 7 June 2019

Ying Liu and Yongmei Liu

The purpose of this paper is to examine the impact mechanism of workers’ perceived justice, trust and job satisfaction (JS) on their continuance participation intention in…

Abstract

Purpose

The purpose of this paper is to examine the impact mechanism of workers’ perceived justice, trust and job satisfaction (JS) on their continuance participation intention in the crowdsourcing market.

Design/methodology/approach

An e-questionnaire was posted as an online task on Zhubajie, and data from 304 valid questionnaires were analyzed using SmartPLS 3 software.

Findings

Results show that crowdsourcing workers’ distributive and interpersonal justice have a significant impact on their trust in the task requester, while procedural and informational justice significantly affect their trust in intermediary management. Workers’ trust in the task requester and in intermediary management positively affects JS, which ultimately affects their continuance participation intention in the crowdsourcing market.

Research limitations/implications

Based on the social exchange theory, this study examines the positive impact of workers’ justice perception on their continuance participation intention. It dissects the inherent mechanism of workers’ justice perception about their continuance participation intention using three variables of trust in the task requester, trust in intermediary management and JS.

Practical implications

Given the positive relationship between workers’ justice perception and continuance participation intention, crowdsourcing intermediary website managers should adopt effective measures to enhance workers’ justice perception to strengthen their continuance participation intention.

Originality/value

This study explores factors that influence workers’ continuance participation intention and their inherent mechanism in the crowdsourcing market based on justice and social exchange theories. It is an extension of research on continuous participation behavior in the crowdsourcing field.

Details

Internet Research, vol. 29 no. 6
Type: Research Article
ISSN: 1066-2243

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Article
Publication date: 22 July 2021

Han Liu, Ying Liu, Gang Li and Long Wen

This study aims to examine whether and when real-time updated online search engine data such as the daily Baidu Index can be useful for improving the accuracy of tourism…

Abstract

Purpose

This study aims to examine whether and when real-time updated online search engine data such as the daily Baidu Index can be useful for improving the accuracy of tourism demand nowcasting once monthly official statistical data, including historical visitor arrival data and macroeconomic variables, become available.

Design/methodology/approach

This study is the first attempt to use the LASSO-MIDAS model proposed by Marsilli (2014) to field of the tourism demand forecasting to deal with the inconsistency in the frequency of data and the curse problem caused by the high dimensionality of search engine data.

Findings

The empirical results in the context of visitor arrivals in Hong Kong show that the application of a combination of daily Baidu Index data and monthly official statistical data produces more accurate nowcasting results when MIDAS-type models are used. The effectiveness of the LASSO-MIDAS model for tourism demand nowcasting indicates that such penalty-based MIDAS model is a useful option when using high-dimensional mixed-frequency data.

Originality/value

This study represents the first attempt to progressively compare whether there are any differences between using daily search engine data, monthly official statistical data and a combination of the aforementioned two types of data with different frequencies to nowcast tourism demand. This study also contributes to the tourism forecasting literature by presenting the first attempt to evaluate the applicability and effectiveness of the LASSO-MIDAS model in tourism demand nowcasting.

Details

International Journal of Contemporary Hospitality Management, vol. 33 no. 6
Type: Research Article
ISSN: 0959-6119

Keywords

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Article
Publication date: 16 December 2019

Xuemei Su, Ming Chen, Jasmine Yur-Austin and Ying Liu

Faced with declining government funding support and rising student loan debt, recently timely graduation in higher education has become a focal point of discussion at many…

Abstract

Purpose

Faced with declining government funding support and rising student loan debt, recently timely graduation in higher education has become a focal point of discussion at many institutions, particularly public universities. Timely graduation requires a student to successfully enroll in and complete a set of required and elective courses, the relationship of which is bound by the courses’ prerequisite requirements. However, due to the fact that class capacity is oftentimes limited and wrongly timed, many students find it challenging to stay on track. A well-structured degree roadmap that takes all factors into consideration and specifies the right courses to take by semester will better guide students’ course selection and thus increase their chance of earning their degrees within the four-year time window. Additionally, it will also allow administrators to do better capacity planning, and hence increase course accessibility to students. The paper aims to discuss these issues.

Design/methodology/approach

In this research, some operational techniques such as line balancing and simulation are applied to restructure and improve degree roadmaps, and assess the resulting outcomes. Some innovative methods are proposed to improve the processes on which students proceed to degree.

Findings

The results based on historical data that contains millions of student records spanning over eight-year time window demonstrate that the improved degree roadmaps can substantially increase students’ chance of completing the degree in a four-year time window. The research findings provide university administrators with cost-effective solutions.

Originality/value

This research breaks a new ground in literature due to its unique approach and focus. To the best of the authors’ knowledge, this research is one of the first attempts to systematically study the impact of degree roadmap on timely graduation. This research focuses on finding solutions that are within the institution’s control, hence the proposed solutions are implementable and will provide university administrators with new tools and perspectives to enhance student success.

Details

International Journal of Educational Management, vol. 34 no. 2
Type: Research Article
ISSN: 0951-354X

Keywords

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Article
Publication date: 20 June 2019

Qiang He, Weifeng Huang, Ying Liu, Xiangfeng Liu, Yongjian Li and Yuming Wang

This paper aims to investigate the influence of the contact status between the seal ring and its support on the seal performance in hydrostatic mechanical face seal.

Abstract

Purpose

This paper aims to investigate the influence of the contact status between the seal ring and its support on the seal performance in hydrostatic mechanical face seal.

Design/methodology/approach

A thermal fluid-solid interaction (TFSI) model of hydrostatic mechanical face seal is further developed, in which the multi-body contacts between components are particularly given more attention. The numerical models of the flow field and complete seal assemblies are developed. A specific energy equation is obtained to simplify the calculation of film temperature. Based on the mechanism for the continuity condition of the physical quantities at the fluid–solid interface, the TFSI model uses an on-line iterative coupling method.

Findings

The contact status between seal ring and its support affects the seal performance significantly. The rotating ring and the stationary ring contribute differently because of the contact status difference.

Originality/value

The contact status between the seal ring and the ring seat is key to gain an insight into the performance of the hydrostatic mechanical face seal thus provides guidance for mechanical seal design.

Details

Industrial Lubrication and Tribology, vol. 71 no. 7
Type: Research Article
ISSN: 0036-8792

Keywords

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Article
Publication date: 28 August 2018

Zhanchao Wang, Fei Guo, Ying Liu, Xiangfeng Liu and Yuming Wang

This paper aims to design a new surface profile with simpler processing technology, which makes the bearing load carrying capacity (LCC) close to that of conventional…

Abstract

Purpose

This paper aims to design a new surface profile with simpler processing technology, which makes the bearing load carrying capacity (LCC) close to that of conventional tilting-pad thrust bearing.

Design/methodology/approach

The paper analyzes the LCC of the thrust pad with crown profile and designs a new profile, whose performance is similar to the crown profile. The laser method is introduced to fabricate the new profile. The profile with tiny crown height can be fabricated by the laser with the proper parameters.

Findings

It was found that there is an optimum value, which is best in terms of the capacity of tilting-pad thrust bearing reach. The new profile with proper parameters can replace the crown profile.

Originality/value

The new profile can replace the crown profile and is easier to be made. The new design method could be adopted for designing the pad surface profile of the tilting-pad thrust bearing.

Details

Industrial Lubrication and Tribology, vol. 70 no. 8
Type: Research Article
ISSN: 0036-8792

Keywords

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Article
Publication date: 8 January 2020

Wanying Liu, Junjie Yang, Yuhong Qiu, Ying Liu and Kuanhai Deng

The preferable concentration of titanium carbide was optimized and added as an additive to the micro-arc oxidation electrolyte to produce a high corrosion-resistant…

Abstract

Purpose

The preferable concentration of titanium carbide was optimized and added as an additive to the micro-arc oxidation electrolyte to produce a high corrosion-resistant coating on D16T aluminum alloy.

Design/methodology/approach

Ceramic coatings were deposited on D16T aluminum alloy by plasma electrolytic oxidation in alkaline silicate electrolytes with micron titanium carbide particle suspending at different concentrations. Influences of additive concentration on morphology, elemental and phase composition and corrosion resistance of doped PEO coatings were evaluated by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and electrochemical methods, respectively.

Findings

Results revealed that suspending titanium carbide additives incorporated into ceramic coatings through discharging channels and chemically transformed into amorphous stage. The content of titanium in the doped coatings increased with the increasing concentration of suspending micron additive. Compared with the coating without particle addition, the corrosion resistance of the coating produced in 8 g/L titanium carbide suspension increased more than 20 times. The result indicated that the incorporation of titanium into the PEO coatings formed on the D16T aluminum alloy could effectively improve the corrosion resistance.

Originality/value

The mechanism of corporation of TiC and the mechanism of improving the corrosion resistance of the coating were proposed.

Details

Anti-Corrosion Methods and Materials, vol. 67 no. 1
Type: Research Article
ISSN: 0003-5599

Keywords

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Article
Publication date: 25 September 2018

Zhanchao Wang, Fei Guo, Ying Liu, Xiangfeng Liu and Yuming Wang

This aim of this paper has been to investigate the squeeze effect of a water-lubricated tilting-pad thrust bearing during start-up and shut-down periods.

Abstract

Purpose

This aim of this paper has been to investigate the squeeze effect of a water-lubricated tilting-pad thrust bearing during start-up and shut-down periods.

Design/methodology/approach

In this paper a numerical model with a squeeze and slippage effect was adopted to analyse the asymmetry characteristic of a tilting-pad thrust bearing during start-up and shut-down periods. A test rig was built to verify numerical results, which were a combined measurement method in which acceleration sensor and torque sensor were used simultaneously to determine the angle change of the thrust pad.

Findings

It was found that as the velocity gradient increased, the difference of the minimum dimensionless film Hmin could be ignored in the start-up process. But in the shut-down process, as the velocity gradient increased, the value of Hmin also increased, which showed that there was an asymmetry characteristic of the tilting bearing in two processes. This phenomenon was verified by measuring the friction torque curve in the test.

Originality/value

The results of the studies demonstrated that the velocity gradient could be designed to reduce the friction of the thrust bearing, which would be beneficial to the working life of the tilting-pad thrust bearing.

Details

Industrial Lubrication and Tribology, vol. 70 no. 9
Type: Research Article
ISSN: 0036-8792

Keywords

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Article
Publication date: 1 April 2021

Ying Liu and Tang Wang

This study aims to propose an integrated model based on the DeLone and McLean Information System Success Model (DMISS) to examine whether quality factors (system, service…

Abstract

Purpose

This study aims to propose an integrated model based on the DeLone and McLean Information System Success Model (DMISS) to examine whether quality factors (system, service and information) can affect user satisfaction and performance of cloud-based marketing systems.

Design/methodology/approach

Recently, technologies change quickly, innovation becomes a vital base of productivity and sustainable growth of businesses is widely accepted. Cyber-physical system technologies help industries change production and marketing cycles according to customers’ needs in real-time. In addition, processing information through cloud service helps companies meet customer needs. The advantages of cloud technology also make it easier for companies to quickly collect the latest data from various sources, making it more effective in decision-making. This research recommends cloud-based marketing to help companies maximize their revenue by providing useful information and better quality for business development. The data were gathered from China automotive companies’ customers. A total of 220 questionnaires were distributed, and 165 (82.5%) usable questionnaires were analyzed using structural equation modeling.

Findings

This study verified that costumers’ perceived information quality, system quality and service quality positively caused the user satisfaction in the cloud-based marketing system.

Practical implications

This paper presents beneficial advice for improving cloud-based marketing systems. Besides, the topic is relevant to cloud-based marketing systems’ success. A better understanding of the impact of intention to use and user satisfaction on cloud-based marketing systems could significantly enhance companies’ success. This paper’s theoretical and practical contributions are expressed to guide organizations and policymakers in increasing cloud-based marketing systems acceptance.

Originality/value

This study empirically tests the relationship of quality factors and performance outcome of cloud-based marketing system through a model based on DeLone and McLean theory. This study bridges the research gap by identifying the factors that drive the adoption of cloud-based services in marketing and the impact of user satisfaction and intention to use on the cloud-based marketing system performance in the case of china companies.

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Article
Publication date: 15 July 2020

Wenbin Gao, Weifeng Huang, Tao Wang, Ying Liu, Zhihao Wang and Yuming Wang

By modeling and analyzing the two-phase mechanical seal of the fan-shaped groove end face, which is prone to phase change, an effective method to study the flow field of…

Abstract

Purpose

By modeling and analyzing the two-phase mechanical seal of the fan-shaped groove end face, which is prone to phase change, an effective method to study the flow field of the mechanical seal when both cavitation and boiling exist simultaneously is found.

Design/methodology/approach

Based on the finite volume method, a fluid model was developed to investigate a two-phase mechanical seal. The validity of the proposed model was verified by comparing with some classical models.

Findings

By modeling and analyzing the two-phase mechanical seal of the fan-shaped groove end face, which is prone to phase change, the analysis of the gap flow field of the mechanical seal was realized when cavitation and boiling existed simultaneously.

Originality/value

Based on the model proposed for different conditions, the pressure and phase states in the shallow groove sealing gap were compared. The phase change rate between the mechanical seal faces was also investigated.

Peer review

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-12-2019-0537/

Details

Industrial Lubrication and Tribology, vol. 72 no. 10
Type: Research Article
ISSN: 0036-8792

Keywords

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