Rui Liu, Jing Sheng, Jie Ma, Guang Yang, Xuefei Dong and Yongsheng Liang
The purpose of this paper is to investigate the knock combustion characteristics, including the combustion pressure, heat release rate (HRR) and knock intensity of aviation…
Abstract
Purpose
The purpose of this paper is to investigate the knock combustion characteristics, including the combustion pressure, heat release rate (HRR) and knock intensity of aviation kerosene fuel, that is, Rocket Propellant 3 (RP-3), on a port-injected two-stoke spark ignition (SI) engine.
Design/methodology/approach
Experimental investigation using a bench test and the statistical analysis of data to reflect the knock combustion characteristics of the two-stroke SI unmanned aerial vehicle (UAV) engine on RP-3 kerosene fuel.
Findings
Under the full load condition of 4,000 rpm, at the ignition timing of 25 degree of crank angle (°CA) before top dead centre (BTDC), the knock combustion is sensitive to the thinner mixture; therefore, the knock begins to occur when the excess air ratio is larger than 1.0. When the excess air ratio is set as 1.2, the knock obviously appears with the highest knock intensity. At the excess air ratio of 1.2, better engine performance is obtained at the ignition timing range of 20-30 °CA BTDC. However, the ignition timing at 30° CA BTDC significantly increases the peak combustion pressure and knock intensity with the advancing heat release process.
Practical implications
Gasoline has a low flash point, a high-saturated vapour pressure and relatively high volatility, and it is a potential hazard near a naked flame at room temperature, which can create significant security risks for its storage, transport and use. The authors adopt a low-volatility single RP-3 kerosene fuel for all vehicles and equipment to minimise the number of different devices using various fuels and improve the military application safety.
Originality/value
Most two-stroke SI UAV engines for military applications burn gasoline. A kerosene-based fuel for stable engine operation can be achieved because the knock combustion can be effectively suppressed through the combined adjustment of the fuel amount and spark timing.
Details
Keywords
Rui Liu, Xiaoping Su, Xiaodong Miao, Guang Yang, Xuefei Dong, Yongsheng Liang and Taiqi Huang
The purpose of this paper is to compare the combustion characteristics, including the combustion pressure, heat release rate (HRR), coefficient of variation (COV) of indicated…
Abstract
Purpose
The purpose of this paper is to compare the combustion characteristics, including the combustion pressure, heat release rate (HRR), coefficient of variation (COV) of indicated mean effective pressure (IMEP), flame development period and combustion duration, of aviation kerosene fuel, namely, rocket propellant 3 (RP-3), and gasoline on a two-stoke spark ignition engine.
Design/methodology/approach
This paper is an experimental investigation using a bench test to reflect the combustion performance of two-stroke spark ignition unmanned aerial vehicle (UAV) engine on gasoline and RP-3 fuel.
Findings
Under low load conditions, the combustion performance and HRR of burning RP-3 fuel were shown to be worse than those of gasoline. Under high load conditions, the average IMEP and the COV of IMEP of burning RP-3 fuel were close to those of gasoline. The difference in the flame development period between gasoline and RP-3 fuel was similar.
Practical implications
Gasoline fuel has a low flash point, high-saturated vapour pressure and relatively high volatility and is a potential hazard near a naked flame at room temperature, which can create significant security risks for its storage, transport and use. Adopting a low volatility single RP-3 fuel of covering all vehicles and equipment to minimize the number of different devices with the use of a various fuels and improve the application safeties.
Originality/value
Most two-stroke spark ignition UAV engines continue to combust gasoline. A kerosene-based fuel operation can be applied to achieve a single-fuel policy.
Details
Keywords
Tong Zhang, Zhiwei Guo, Xuefei Li and Zumin Wu
This study aims to investigate the potential of wood as a water-lubricated bearing material, determine the factors influencing the water-lubricated properties of wood and identify…
Abstract
Purpose
This study aims to investigate the potential of wood as a water-lubricated bearing material, determine the factors influencing the water-lubricated properties of wood and identify suitable alternatives to Lignum vitae.
Design/methodology/approach
Three resource-abundant wood species, Platycladus orientalis, Cunninghamia lanceolata and Betula platyphylla, were selected, and their properties were compared with those of Lignum vitae. The influencing mechanism of the tribological properties of different woods under water lubrication was thoroughly analyzed, in conjunction with the characterization and testing of mechanical properties, micromorphology and chemical composition.
Findings
The findings reveal that the mechanical properties and inclusions of wood are the primary factors affecting its tribological properties, which are significantly influenced by the micromorphology and chemical composition. The friction experiment results demonstrate that Lignum vitae exhibits the best tribological properties among the four wood species. The tribological properties of Platycladus orientalis are comparable to those of Lignum vitae, being only 17.1% higher. However, it is noted that higher mechanical properties can exacerbate the wear of the grinding pair.
Originality/value
The originality of this study lies in the combination of friction experiments and wood performance tests to identify the factors contributing to the superior water lubrication performance of wood, thereby guiding the application and improvement of different wood types in water-lubricated bearings.
Peer review
The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-07-2024-0284/
Details
Keywords
Shang Chen, Qingfei Min and Xuefei Xu
As social commerce migrates to the mobile platform, mobile social commerce (ms–commerce), an emerging way of conducting social commerce in the mobile environment, is gaining…
Abstract
Purpose
As social commerce migrates to the mobile platform, mobile social commerce (ms–commerce), an emerging way of conducting social commerce in the mobile environment, is gaining popularity among mobile users. Although impulse buying in social commerce has been the focus of scholars in recent years, individuals' impulse-buying behavior in ms–commerce has not been highlighted and therefore is worth investigating. This study addressed that gap by differentiating and monitoring the impacts that three key targets of social identification in ms–commerce exerted on impulse buying. Furthermore, previous studies had highlighted the importance of culture in impulse buying in other contexts, so the authors examined how the effects of the key identification targets differed across cultures, as a result of cultural diversity among the ms–commerce users. Finally, the authors drew upon the lens of information technology (IT) affordances to explore how different combinations of ms–commerce affordances influenced each target of identification.
Design/methodology/approach
This research first applied a qualitative methodology by using semi-structured interviews with 27 ms–commerce users to extract the relevant subdimensions of IT affordances in ms–commerce. Then, the authors tested their hypotheses with survey data collected from the United States and China.
Findings
The results clearly illustrate that three key targets of social identification had varying impacts on impulse buying in different cultural dimensions. In addition, nearly all of the proposed IT affordances in ms–commerce aided users in building multiple identifications, to various degrees.
Originality/value
This study extends social commerce research by examining the important role that social identification plays in impulse buying in the mobile environment. Moreover, unlike previous studies that mainly had focused on ordinary buying in social commerce across cultures, this study investigated the relative importance of the targets of social identification on impulse buying in different espoused cultural dimensions. Importantly, the authors used a technology affordance lens to also uncover the context-specific stimulators of separate identification targets, thus going beyond the existing body of knowledge that focused on general beliefs.
Details
Keywords
Jing Luo, Fevzi Okumus and Babak Taheri
This study aims to analyze Chinese and Western visitors’ on‐line reviews of Shenzhen under five dimensions: catering, accommodation, transportation, travel and shopping.
Abstract
Purpose
This study aims to analyze Chinese and Western visitors’ on‐line reviews of Shenzhen under five dimensions: catering, accommodation, transportation, travel and shopping.
Design/methodology/approach
This study used a multidimensional discourse analysis to assess visitors’ experience, perception and emotional evaluations of Shenzhen in reviews on TripAdvisor.com.
Findings
The findings suggest that both Chinese and Western visitors show positive perceptions of Shenzhen’s transportation convenience and options and show great interest in folk culture. Both groups focus on shopping, service and price but believe that the prices in Shenzhen are high.
Research limitations/implications
The classification of reviews highlights tourism elements in Shenzhen, which can offer implications for destination image formation for similar destinations.
Practical implications
This study offers suggestions on how to build an appealing destination that meets both Chinese and Western tourists’ needs.
Social implications
This study enriches the theory of tourism image perception of Shenzhen as it relates to language and culture.
Originality/value
This study offers implications on building an appealing destination that meets Chinese and Western tourists’ expectations.
深圳目的地形象感知:基于中西方游客在线评论的话语分析
摘要
研究目的
本研究从餐饮、住宿、交通、旅游、购物五个维度分析中西方游客对深圳的评价。
研究方法
本研究采用多维语篇分析来评估访问者对深圳的体验、感知和情感评价。
研究发现
调查结果表明, 中国和西方游客对深圳的交通便利和选择都表现出积极的看法, 并对民俗文化表现出浓厚的兴趣。两组都关注购物、服务和价格, 但认为深圳的物价偏高。
研究意义
评论的分类突出了深圳的旅游元素,可以为相似目的地形象的构建提供启示。
研究原创性
本研究丰富了深圳旅游形象感知与语言相关的理论。它为建设一个满足中国和西方游客期望的吸引人的目的地提供了启示。
关键词
旅游目的地形象, 话语分析, 深圳, 多维话语分析, 中西方游客
文章类型: 研究型论文
Details
Keywords
This study aims to explore how earnings management techniques are affected by corporate financial debt risk (FDR), internal control (IC) effectiveness and CEO education.
Abstract
Purpose
This study aims to explore how earnings management techniques are affected by corporate financial debt risk (FDR), internal control (IC) effectiveness and CEO education.
Design/methodology/approach
The study uses a sample from listed firms in China from 2010 to 2017, comprising different industries, including agriculture, forestry, livestock farming and fishing; mining; manufacturing; electric power, gas and water production and supply; construction; transport and storage; information technology; the real estate industry; social services; and communication and cultural. The regression analysis is used to test the hypotheses. The two-stage least squares technique is used to check for endogeneity issues.
Findings
The study finds that firms are less likely to manage real earnings when they have more robust IC and FDR. Likewise, companies with weak ICs are more likely to manipulate real earnings. Besides, the study finds an influence of CEO education on the relationship between IC, FDR and real earnings management (REM). These results can be applied to the sectors in the sample covered by the research, and the authors do not overlook the energy industry sector for the importance of its role in the economy.
Research limitations/implications
There are some limitations for the researcher when performing any research, and this study is no exception. Researchers are urged to take these circumstances into consideration when generalizing or comparing the results because the methods used to calculate the measurement variables in each study may differ somewhat from those used in other research. In addition, expanding the current research design to incorporate additional nations may be an area of interest for future research and could aid in evaluating the effects of nation-specific elements (such as inflation, culture, legal systems and political considerations) on the usefulness of IC and decreasing FDR. Second, the current study focuses on the impact of IC and FDR on REM; this paper does not dissect the “black box” of IC and consider how each element affects earnings management. Future research may need to focus specifically on how effective IC would affect earnings management and precisely what IC mechanisms would discourage the management of earnings.
Practical implications
Helping companies listed in China to make decisions and improve investors’ vision of the results of real companies’ businesses, as well as helping management to avoid falling into debt risk and the consequent effects and manipulation of earnings.
Originality/value
By highlighting the significance of IC and debt risk in enhancing information quality in China, the results contribute to the body of work examining the relationship between IC, FDR and REM. In addition, this study uses a CEO’s education to moderate this link.