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Article
Publication date: 11 July 2019

Eryong Liu, Yingxin Zhang, Xiang Wang, Zhixiang Zeng, Huiling Du and Hongmei Qin

This paper aims to improve the tribocorrosion properties of 316L, thus WC/Ni60 coated 316L was prepared by thermal spraying technique.

193

Abstract

Purpose

This paper aims to improve the tribocorrosion properties of 316L, thus WC/Ni60 coated 316L was prepared by thermal spraying technique.

Design/methodology/approach

Composition and microstructure of WC/Ni60 coating was investigated, and tribological properties of 316 L and WC/Ni60 coating were studied under dry sliding, deionized water and artificial seawater.

Findings

The results showed that WC/Ni60 coating was lamellar structure, and the phase composition consisted of γ-Ni solid solution, carbides and borides. Furthermore, the hardness and corrosion resistance of 316 L in static seawater and wear resistance in dry sliding were improved by WC reinforced nickel-based coating. Furthermore, tribocorrosion results demonstrated that wear resistance of WC/Ni60 coating was also significantly better than 316 L, especially for higher load at artificial seawater. The reason can be attributed to the fact that the passive film of WC/Ni60 coating consisted of tungsten carbide, Ni(OH)2 and FeOOH for WC/Ni60 coating and only FeOOH for 316 L.

Originality/value

According to this study, it can be concluded that WC phases acted as a role in resisting the wear damages. Meanwhile, Ni-based materials performed well in corrosion resistance. Thus, the combined-effect Ni-based alloys and WC phases in WC/Ni60 coating showed better tribocorrosion performance than 316 L.

Details

Industrial Lubrication and Tribology, vol. 71 no. 6
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 10 August 2018

Fuliang Ma, Zhixiang Zeng and Yimin Gao

This paper aims to study the tribocorrosion and the surface repassivation behaviors of Monel 400 alloy in artificial seawater.

196

Abstract

Purpose

This paper aims to study the tribocorrosion and the surface repassivation behaviors of Monel 400 alloy in artificial seawater.

Design/methodology/approach

In this study, the tribocorrosion behavior of Monel 400 alloy was studied under different applied loads in artificial seawater by using a pin-on-disk tribometer equipped with an electrochemical workstation. The applied loads were selected ranging from 50 to 200 N. The surface repassivation behavior of Monel 400 alloy was studied by X-ray photoelectron spectroscopy.

Findings

It was demonstrated that mass loss was determined by the combined effect of mechanical wear and chemical corrosion. The surface repassivation mechanism of the alloy is that layer corrosion product film formed on the surface of Monel 400 alloy, which can protect metal matrix from future corrosion.

Originality/value

This research adds original content in revealing the tribocorrosion and surface repassivation behaviors of Monel 400 alloy under different loads, which offer a theoretical basis for the application under the corrosion and wear environment of Monel 400.

Details

Industrial Lubrication and Tribology, vol. 70 no. 7
Type: Research Article
ISSN: 0036-8792

Keywords

Available. Open Access. Open Access
Article
Publication date: 16 October 2024

Yang Li, Zhicheng Zheng, Yaochen Qin, Haifeng Tian, Zhixiang Xie and Peijun Rong

Drought is the primary disaster that negatively impacts agricultural and animal husbandry production. It can lead to crop reduction and even pose a threat to human survival in…

122

Abstract

Purpose

Drought is the primary disaster that negatively impacts agricultural and animal husbandry production. It can lead to crop reduction and even pose a threat to human survival in environmentally sensitive areas of China (ESAC). However, the phases and periodicity of drought changes in the ESAC remain largely unknown. Thus, this paper aims to identify the periodic characteristics of meteorological drought changes.

Design/methodology/approach

The potential evapotranspiration was calculated using the Penman–Monteith formula recommended by the Food and Agriculture Organization of the United Nations, whereas the standardized precipitation evaporation index (SPEI) of drought was simulated by coupling precipitation data. Subsequently, the Bernaola-Galvan segmentation algorithm was proposed to divide the periods of drought change and the newly developed extreme-point symmetric mode decomposition to analyze the periodic drought patterns.

Findings

The findings reveal a significant increase in SPEI in the ESAC, with the rate of decline in drought events higher in the ESAC than in China, indicating a more pronounced wetting trend in the study area. Spatially, the northeast region showed an evident drying trend, whereas the southwest region showed a wetting trend. Two abrupt changes in the drought pattern were observed during the study period, namely, in 1965 and 1983. The spatial instability of moderate or severe drought frequency and intensity on a seasonal scale was more consistent during 1966–1983 and 1984–2018, compared to 1961–1965. Drought variation was predominantly influenced by interannual oscillations, with the periods of the components of intrinsic mode functions 1 (IMF1) and 2 (IMF2) being 3.1 and 7.3 years, respectively. Their cumulative variance contribution rate reached 70.22%.

Research limitations/implications

The trend decomposition and periods of droughts in the study area were analyzed, which may provide an important scientific reference for water resource management and agricultural production activities in the ESAC. However, several problems remain unaddressed. First, the SPEI considers only precipitation and evapotranspiration, making it extremely sensitive to temperature increases. It also ignores the nonstationary nature of the hydrometeorological water process; therefore, it is prone to bias in drought detection and may overestimate the intensity and duration of droughts. Therefore, further studies on the application and comparison of various drought indices should be conducted to develop a more effective meteorological drought index. Second, the local water budget is mainly affected by surface evapotranspiration and precipitation. Evapotranspiration is calculated by various methods that provide different results. Therefore, future studies need to explore both the advantages and disadvantages of various evapotranspiration calculation methods (e.g. Hargreaves, Thornthwaite and Penman–Monteith) and their application scenarios. Third, this study focused on the temporal and spatial evolution and periodic characteristics of droughts, without considering the driving mechanisms behind them and their impact on the ecosystem. In future, it will be necessary to focus on a sensitivity analysis of drought indices with regard to climate change. Finally, although this study calculated the SPEI using meteorological data provided by China’s high-density observatory network, deviations and uncertainties were inevitable in the point-to-grid spatialization process. This shortcoming may be avoided by using satellite remote sensing data with high spatiotemporal resolution in the future, which can allow pixel-scale monitoring and simulation of meteorological drought evolution.

Practical implications

Under the background of continuous global warming, the climate in arid and semiarid areas of China has shown a trend of warming and wetting. It means that the plant environment in this region is getting better. In the future, the project of afforestation and returning farmland to forest and grassland in this region can increase the planting proportion of water-loving tree species to obtain better ecological benefits. Meanwhile, this study found that in the relatively water-scarce regions of China, drought duration was dominated by interannual oscillations (3.1a and 7.3a). This suggests that governments and nongovernmental organizations in the region should pay attention to the short drought period in the ESAC when they carry out ecological restoration and protection projects such as the construction of forest reserves and high-quality farmland.

Originality/value

The findings enhance the understanding of the phasic and periodic characteristics of drought changes in the ESAC. Future studies on the stress effects of drought on crop yield may consider these effects to better reflect the agricultural response to meteorological drought and thus effectively improve the tolerance of agricultural activities to drought events.

Details

International Journal of Climate Change Strategies and Management, vol. 17 no. 1
Type: Research Article
ISSN: 1756-8692

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Article
Publication date: 16 March 2022

Xiaoxing Liang and Zhixiang Zhou

With the rapid economic growth and urbanization development, regional environmental problems have attracted increasing attention. The study on analyzing cities’ capacity on…

81

Abstract

Purpose

With the rapid economic growth and urbanization development, regional environmental problems have attracted increasing attention. The study on analyzing cities’ capacity on resource utilization and environmental protection is practically significant because of the industrial agglomeration in an urban area. This study aims to measure environmental efficiency of urban industrial water utilization by comparing input, output and undesirable outputs variables of cities.

Design/methodology/approach

This paper combines data envelopment analysis basic approach with regression to discover the environmental efficiency score of cities and their influence factors. A set of slack-based measure (SBM) model is constructed for calculating the environmental efficiency score by considering both desirable and unendurable outputs.

Findings

This paper analyzes the industrial water utilization efficiency for China from the city level by evaluating the performance for up to 200 mainland Chinese cities during 2012–2016 under SBM model. Then, 2C Tobit regression is used to measure the determining factors of industrial water utilization efficiency from the angle of natural, social, municipal and industrial structure factors. The empirical study results show huge room for improvement in industrial water utilization in China, while the average citizen efficiency scores maintain a level of about 0.5.

Originality/value

Significant differences exist in the regional efficiency in different cities in China. Per capita GDP, a total length of drainage pipe and whether the area is coastal or not have significant positive impacts on the water utilization efficiency, while the proportion of secondary industry to GDP has a significant negative influence. Specific recommendations are proposed based on the local industrial water utilization efficiency scores, such as improving urban infrastructure and adopting a more flexible water pricing system.

Details

Management of Environmental Quality: An International Journal, vol. 33 no. 4
Type: Research Article
ISSN: 1477-7835

Keywords

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Article
Publication date: 26 August 2024

Junjie Gong, Zhixiang Li, Qingqing Lin and Kunhong Hu

This study aims to explore the synthesis and tribological performances of di-n-octyl sebacate (DOS) synthesized with spherical nano-MoS2/sericite (SMS) and carboxylated SMS (CSMS…

14

Abstract

Purpose

This study aims to explore the synthesis and tribological performances of di-n-octyl sebacate (DOS) synthesized with spherical nano-MoS2/sericite (SMS) and carboxylated SMS (CSMS) as catalysts.

Design/methodology/approach

SMS and CSMS were used as esterification catalysts to synthesize DOS from sebacic acid and n-octanol. The two catalysts were in situ dispersed in the synthesized DOS after the reaction to form suspensions. The tribological performances of the two suspensions after 20 days of storage were studied.

Findings

CSMS was more stably dispersed in DOS than SMS, and they reduced friction by 55.6% and 22.2% and wear by 51.3% and 56.5%, respectively. Such results were mainly caused by the COOH on CSMS, which was more conducive to improving the dispersion and friction reduction of CSMS than wear resistance. Another possible reason was the difference between the dispersion amounts of CSMS and SMS in DOS. The sericite of SMS was converted into SiO2 to enhance wear resistance, while that of CSMS only partially generated SiO2, and the rest still remained on the surface to reduce friction.

Originality/value

This work provides a more effective SMS catalytical way for DOS synthesis than the traditional inorganic acid catalytical method. SMS does not need to be separated after reaction and can be dispersed directly in DOS as a lubricant additive. Replacing SMS with CSMS can produce a more stable suspension and reduce friction significantly. This work combined the advantages of surface carboxylation modification and in situ catalytic dispersion and provided alternatives for the synthesis of DOS and the dispersion of MoS2-based lubricant additives.

Details

Industrial Lubrication and Tribology, vol. 76 no. 9
Type: Research Article
ISSN: 0036-8792

Keywords

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Case study
Publication date: 1 October 2011

Michael Roberto, Grace Chun Guo and Crystal X. Jiang

International business

Abstract

Subject area

International business

Study level/applicability

Undergraduate/graduate/executive education.

Case overview

China has become the world's largest producer of automobiles, surpassing the USA and Japan. The Chinese auto industry differs quite significantly from those countries though. While the industry exhibits a substantial degree of concentration in the USA and Japan in early 2011, it remained highly fragmented in China. The Chinese Central Government had announced a desire for consolidation, yet it remained unclear whether a significant shakeout would occur in the near term.

Like many Chinese automakers, Chang'an partnered with well-known global auto makers to develop, produce, and distribute its products. In the coming years, Chang'an hoped to develop more independence from its foreign partners, including the production and distribution of self-branded cars. However, the company grappled with how it could strive for independence while managing its existing joint ventures. Executives worried too about how to compete with foreign automakers who had achieved global economies of scale.

The case provides a rich description of the evolution of the Chinese auto industry, and it documents how the Chinese industry differs from other global markets. Readers can analyze the extent to which they believe scale economies provide foreign firms an advantage over smaller Chinese rivals, and they can evaluate the conventional wisdom regarding the industry's minimum efficient scale. The case also provides a detailed account of Chang'an's rise to prominence. The case concludes by offering an in-depth description of the firm's key rivals, and it presents the key questions being considered by Chang'an executives in 2011.

Expected learning outcomes

Enables students to examine how and why an industry's structure can differ substantially across geographic markets.

Enables students to examine whether the need to achieve economies of scale may cause substantial consolidation in the Chinese auto industry.

Provides an opportunity to evaluate the pros and cons of the joint venture strategies employed in China.

Provides an opportunity to examine how a relatively small firm can position itself against large multinationals in a high-growth emerging market.

Supplementary materials

Teaching notes.

Details

Emerald Emerging Markets Case Studies, vol. 1 no. 4
Type: Case Study
ISSN: 2045-0621

Keywords

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Article
Publication date: 5 May 2020

Hongquan Chen, Zhizhou Jin, Quanke Su and Gaoyu Yue

The megaproject is a vital innovation ecosystem for participants engaging in technological adoption and integration to achieve project goals. The purpose of this paper is to…

1464

Abstract

Purpose

The megaproject is a vital innovation ecosystem for participants engaging in technological adoption and integration to achieve project goals. The purpose of this paper is to examine how ecosystem captains build and operate a megaproject innovation ecosystem (MIE). To be more specific, we conducted an in-depth case study to identify the roles played by ecosystem captains in establishing and managing a megaproject innovation ecosystem.

Design/methodology/approach

Based on the Hong Kong-Zhuhai-Macau Bridge project, the data we collected range from 2010 to 2019 and include semi-structured interviews, informal conversations, and archival documents. We employed an inductive theory building approach to address our research question and analyzed our data using the coding process and Atlas.ti software.

Findings

We find that the ecosystem captains themselves are client organizations that have evolved with the ecosystem during four distinct yet inter-related phases. In addition, we find that the captains’ roles of the client organizations include two typical activities: ecosystem establishment and ecosystem collaboration. The ecosystem captains first frame problems, plan innovative activities, set rules, and select participants for the establishment of the ecosystem, and then orchestrate resources, buffer conflicts, incorporate innovative networks, and cultivate an innovation culture to create a collaborative ecosystem.

Originality/value

This study proposes a theoretical framework showing how ecosystem captains engage in MIE to manage innovative activities during different stages. It highlights the importance of captainship roles in client organizations in a megaproject.

Details

Engineering, Construction and Architectural Management, vol. 28 no. 3
Type: Research Article
ISSN: 0969-9988

Keywords

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