Su Yong and Gong Wu-Qi
Abnormal vibrations often occur in the liquid oxygen kerosene transmission pipelines of rocket engines, which seriously threaten their safety. Improper handling can result in…
Abstract
Purpose
Abnormal vibrations often occur in the liquid oxygen kerosene transmission pipelines of rocket engines, which seriously threaten their safety. Improper handling can result in failed rocket launches and significant economic losses. Therefore, this paper aims to examine vibrations in transmission pipelines.
Design/methodology/approach
In this study, a three-dimensional high-pressure pipeline model composed of corrugated pipes, multi-section bent pipes, and other auxiliary structures was established. The fluid–solid coupling method was used to analyse vibration characteristics of the pipeline under various external excitations. The simulation results were visualised using MATLAB, and their validity was verified via a thermal test.
Findings
In this study, the vibration mechanism of a complex high-pressure pipeline was examined via a visualisation method. The results showed that the low-frequency vibration of the pipe was caused by fluid self-excited pressure pulsation, whereas the vibration of the engine system caused a high-frequency vibration of the pipeline. The excitation of external pressure pulses did not significantly affect the vibrations of the pipelines. The visualisation results indicated that the severe vibration position of the pipeline thermal test is mainly concentrated between the inlet and outlet and between the two bellows.
Practical implications
The results of this study aid in understanding the causes of abnormal vibrations in rocket engine pipelines.
Originality/value
The causes of different vibration frequencies in the complex pipelines of rocket engines and the propagation characteristics of external vibration excitation were obtained.
Details
Keywords
Xinwei Li, Xi Li, Tingyue Kuang, Lulu Cheng and Qi Wu
Geographical Indication (GI) products represent a distinct association between a product and its specific geographic origin. While scholars have acknowledged the impact of GI…
Abstract
Purpose
Geographical Indication (GI) products represent a distinct association between a product and its specific geographic origin. While scholars have acknowledged the impact of GI products on destination marketing, there exists a dearth of research concerning the underlying mechanism through which the perceived value of GI products influences consumers' intention to visit the region of origin.
Design/methodology/approach
This study utilizes the cognitive appraisal theory as a basis for constructing a conceptual framework to investigate the association between the perceived value of GI products, emotional reactions and destination brand awareness.
Findings
By placing particular emphasis on the diverse impacts of perceived value on tourists' affective responses and travel intentions, the results of this research offer significant contributions to the field of destination marketing.
Originality/value
A deeper understanding of the perceived value of GI products can enable destination marketers to effectively attract prospective tourists and foster a stronger connection between tourists and the regions of origin.
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Wu Yan and Lisa Catherine Ehrich
The purpose of this paper is to provide an understanding of principal preparation and training in China by providing a background discussion of principal preparation in a number…
Abstract
Purpose
The purpose of this paper is to provide an understanding of principal preparation and training in China by providing a background discussion of principal preparation in a number of countries. As an illustration, it provides an overview of the curriculum used in the initial preparation of school principals at Beijing Normal University.
Design/methodology/approach
The paper draws mainly on writing and research from China, Australia and the USA to explore principal preparation and training in China.
Findings
In addition to providing a rich description of principal preparation in China, the paper's main findings comprise seven key challenges that confront China as it endeavours to provide quality principal preparation. These challenges include China's diversity and uneven social, cultural and educational development; limited resources in some regions throughout China; the place and importance of study tours for principal preparation; the teaching approach used to train principals; the process used for assessing principal learning during their training programs; the limited transfer of learning from the classroom to the school environment; and the timing of training for principals.
Practical implications
Each of the challenges arising here raises important practical implications for developers of principal training programs.
Originality/value
The paper paints a picture of principal preparation in China and raises a number of issues and challenges with which it continues to grapple. Of note is that China is not alone in facing some of these ongoing concerns.
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Mai T. Said and Mona A. ElBannan
The purpose of this study is to examine the impact of firm environmental, social and governance (ESG) rating scores on market perception and stock behavior from 2017 to 2021 while…
Abstract
Purpose
The purpose of this study is to examine the impact of firm environmental, social and governance (ESG) rating scores on market perception and stock behavior from 2017 to 2021 while controlling for COVID-19 severity score.
Design/methodology/approach
The authors used panel regression models with robust standard errors based on cross-country and cross-industry sample of 1,324 ESG firms from 25 emerging countries across four regions. Four separate regression analyses are used. Hausman test is used to determine whether fixed-effect (FE) or random-effect approaches should be used in regression models. Lagrange multiplier test is used to test for time FEs, and F-test for individual effects to choose between pooled ordinary least squares model and FE. Two-unit root tests are conducted to check stationarity. Heteroskedasticity and serial correlation were controlled through a robust covariance matrix estimation.
Findings
The authors provide evidence that the stakeholder theory persists in emerging countries. Overall, the results suggest that firms’ stock behavior is positively associated with the level of environmental and social performance in the region. However, the results do not provide empirical evidence to support the link between ESG performance and stock market perception proxied by the price-to-sales ratio. The results suggest that Refinitiv and Bloomberg ESG rating scores have a positive impact on stock performance in emerging markets, albeit the Bloomberg rating score is insignificant.
Practical implications
Favorable impact of environmental and social performance on stock performance suggests that policymakers should take initiatives to raise awareness toward investments in ESG projects. Evidence shows that ESG stock performance in emerging markets does not insulate firms from the COVID-19 severity. Furthermore, this study highlights the inconsistency in calculating the ESG ratings, therefore, a more standardized approach is recommended to support investors seeking sustainable investments.
Social implications
The findings have social implications for investors with proenvironmental preferences and nonpecuniary motives for ethical investments. Asset fund managers should develop ESG investment strategies to promote investor preferences that are linked to the proenvironmental and prosocial attitudes by increasing their investments in stocks of firms that behave ethically and support the environment. Furthermore, the findings show that investors pay a price for ethical and socially responsible investments as they are evaluating the environmental and social activities, hence, the firm ESG profile influences equity valuation and risk assessment.
Originality/value
The study extends the literature and provides evidence from the unique setting of emerging markets by analyzing the relationship between ESG rating scores and the COVID-19 severity scores on one hand, and stock behavior and market perception on the other.