Yichen Zhang, Feng Cui, Wu Liu, Wenhao Zhu, Yiming Xiao, Qingcheng Guo and Jiawang Mou
Endurance time is an important factor limiting the progress of flapping-wing aircraft. In this study, this paper developed a prototype of a double-wing flapping-wing micro air…
Abstract
Purpose
Endurance time is an important factor limiting the progress of flapping-wing aircraft. In this study, this paper developed a prototype of a double-wing flapping-wing micro air vehicle (FMAV) that mimics insect-scale flapping wing for flight. Besides, novel methods for optimal selection of motor, wing length and battery to achieve prolonged endurance are proposed. The purpose of this study is increasing the flight time of double-wing FMAV by optimizing the flapping mechanism, wings, power sources, and energy sources.
Design/methodology/approach
The 20.4 g FMAV prototype with wingspan of 21.5 cm used an incomplete gear flapping wing mechanism. The motor parameters related to the lift-to-power ratio of the prototype were first identified and analyzed, then theoretical analysis was conducted to analyze the impact of wing length and flapping frequency on the lift-to-power ratio, followed by practical testing to validate the theoretical findings. After that, analysis and testing examined the impact of battery energy density and efficiency on endurance. Finally, the prototype’s endurance duration was calculated and tested.
Findings
The incomplete gear facilitated 180° symmetric flapping. The motor torque constant showed a positive correlation with the prototype’s lift-to-power ratio. It was also found that the prototype achieved the best lift-to-power ratio when using 100 mm wings.
Originality/value
A gear-driven flapping mechanism was designed, capable of smoothly achieving 180° symmetric flapping. Besides, factors affecting long-duration flight – motor, wings and battery – were identified and a theoretical flight duration analysis method was developed. The experimental result proves that the FMAV could achieve the longest hovering time of 705 s, outperforming other existing research on double-wing FMAV for improving endurance.
Details
Keywords
Feng Cui, Dong Gao and Jianhua Zheng
The main reason for the low accuracy of magnetometer-based autonomous orbit determination is the coarse accuracy of the geomagnetic field model. Furthermore, the geomagnetic field…
Abstract
Purpose
The main reason for the low accuracy of magnetometer-based autonomous orbit determination is the coarse accuracy of the geomagnetic field model. Furthermore, the geomagnetic field model error increases obviously during geomagnetic storms, which can still further reduce the navigation accuracy. The purpose of this paper is to improve the accuracy of magnetometer-based autonomous orbit determination during geomagnetic storms.
Design/methodology/approach
In this paper, magnetometer-based autonomous orbit determination via a measurement differencing extended Kalman filter (MDEKF) is studied. The MDEKF algorithm can effectively remove the time-correlated portion of the measurement error and thus can evidently improve the accuracy of magnetometer-based autonomous orbit determination during geomagnetic storms. Real flight data from Swarm A are used to evaluate the performance of the MDEKF algorithm presented in this study. A performance comparison between the MDEKF algorithm and an extended Kalman filter (EKF) algorithm is investigated for different geomagnetic storms and sampling intervals.
Findings
The simulation results show that the MDEKF algorithm is superior to the EKF algorithm in terms of estimation accuracy and stability with a short sampling interval during geomagnetic storms. In addition, as the size of the geomagnetic storm increases, the advantages of the MDEKF algorithm over the EKF algorithm become more obvious.
Originality/value
The algorithm in this paper can improve the real-time accuracy of magnetometer-based autonomous orbit determination during geomagnetic storms with a low computational burden and is very suitable for low-orbit micro- and nano-satellites.
Details
Keywords
The purpose of this paper is to deeply study and compare the dual and single hedging strategy, from the direct and cross hedging perspective.
Abstract
Purpose
The purpose of this paper is to deeply study and compare the dual and single hedging strategy, from the direct and cross hedging perspective.
Design/methodology/approach
The authors not only first consider the dual hedge of integrated risks in this oil prices and foreign exchange rates setting but also make a novel comparison between the dual and single hedging strategy from a direct and cross hedging perspective. In total, six econometric models (to conduct one-step-ahead out-of-sample rolling estimation of the optimal hedge ratio) and two hedging performance criteria are employed in two different hedging backgrounds (direct and cross hedging).
Findings
Results show that in the direct hedging background, a dual hedge cannot outperform the single hedge. But in the cross dual hedging setting, a dual hedge performs much better, possibly because the dual hedge brings different levels of advantages and disadvantages in the two different settings and the superiority of the dual hedge is more obvious in the cross dual hedging setting.
Originality/value
The existing literature that deals with oil prices and foreign exchange rates mostly concentrates on their relationship and comovements, while the dual hedge of integrated risks in this setting remains underresearched. Besides, the existing literature that deals with dual hedge gets its conclusions only based on a single specific background (direct or cross hedging) and lacks deeper investigation. In this paper, the authors expand the width and depth of the existing literature. Results and implications are revealing.
Details
Keywords
Suyun Liu, Hu Liu, Ningning Shao, Zhijun Dong, Rui Liu, Li Liu and Fuhui Wang
Polyaniline (PANI) has garnered attention for its potential applications in anticorrosion fields because of its unique properties. Satisfactory outcomes have been achieved when…
Abstract
Purpose
Polyaniline (PANI) has garnered attention for its potential applications in anticorrosion fields because of its unique properties. Satisfactory outcomes have been achieved when using PANI as a functional filler in organic coatings. More recently, research has extensively explored PANI-based organic coatings with self-healing properties. The purpose of this paper is to provide a summary of the active agents, methods and mechanisms involved in the self-healing of organic coatings.
Design/methodology/approach
This study uses specific doped acids and metal corrosion inhibitors as active and self-healing agents to modify PANI using the methods of oxidation polymerization, template synthesis, nanosheet carrier and nanocontainer loading methods. The anticorrosion performance of the coatings is evaluated using EIS, LEIS and salt spray tests.
Findings
Specific doped acids and metal corrosion inhibitors are used as active agents to modify PANI and confer self-healing properties to the coatings. The coatings’ active protection mechanism encompasses PANI’s own passivation ability, the adsorption of active agents and the creation of insoluble compounds or complexes.
Originality/value
This paper summarizes the active agents used to modify PANI, the procedures used for modification and the self-healing mechanism of the composite coatings. It also proposes future directions for developing PANI organic coatings with self-healing capabilities. The summaries and proposals presented may facilitate large-scale production of the PANI organic coatings, which exhibit outstanding anticorrosion competence and self-healing properties.
Details
Keywords
Muhammad Fadhly Rizky Octavio and Doddy Setiawan
This study aims to investigate the influence of public attention and media through the internet on corporate disclosures related to climate change. As public awareness of…
Abstract
Purpose
This study aims to investigate the influence of public attention and media through the internet on corporate disclosures related to climate change. As public awareness of environmental issues and the urgency of addressing climate change increases, pressure is mounting on companies to be transparent about their actions and contributions to climate change mitigation.
Design/methodology/approach
This study uses regression analysis to examine the relationship between public and media attention and corporate climate change disclosure. The panel data consists of information from 142 mining companies in the ASEAN region from 2017 to 2021.
Findings
The research findings show that public and media attention through the internet positively and significantly influences companies’ disclosure regarding their climate change actions. Companies that receive higher levels of public and media scrutiny through the internet tend to disclose more information regarding their climate change mitigation initiatives, strategies and performance. This highlights the importance of public and media attention in driving corporate transparency and accountability in addressing this global challenge.
Practical implications
This research emphasizes the need for companies to proactively engage the public and media on the internet in climate change disclosure strategies. By recognizing the influence of these external stakeholders, companies can design more effective communication and reporting approaches to build legitimacy, enhance their reputation and effectively demonstrate their commitment to contributing to climate change mitigation efforts.
Originality/value
The novelty of this research lies in its study of the role of public attention and media through the internet as a driver of climate change disclosure by companies. Public attention is measured using data from Google Trends as the novelty of this research.
Details
Keywords
Taotao Deng, Ting Dan and Weishu Zhao
High-speed railway (HSR) substantially affects tourism development, but this impact remains somewhat controversial. This study aims to explore the HSR–tourism nexus from the…
Abstract
Purpose
High-speed railway (HSR) substantially affects tourism development, but this impact remains somewhat controversial. This study aims to explore the HSR–tourism nexus from the perspective of Chinese local governance. In the context of promotion tournament model in China, this study attempts to explain such controversy by including local leaders.
Design/methodology/approach
Based on a data set from 25 cities in China’s Yangtze River Delta region during 2005–2019, this study uses a panel data regression model to examine local leaders’ moderating role in the HSR–tourism nexus.
Findings
The tenure of local leaders has a significant moderating role in the impact of HSR implementation on tourism development. Furthermore, a shorter leaders’ tenure strengthens the boost to tourism development from HSR service.
Originality/value
This paper enriches theoretical framework of leaders’ tournament theory. In addition, this study provides a new perspective to understand the HSR–tourism nexus better. This study identifies the moderating role of local leaders in the HSR–tourism nexus and expands the mechanism research of HSR–tourism nexus, which helps to explain the controversy of the HSR–tourism nexus.
目的
高速铁路(HSR)对旅游业的发展有很大的影响, 但这种影响仍有一定的争议性。本研究从中国地方治理的角度探讨了高铁-旅游之间的关系。在中国晋升锦标赛模式的背景下, 本研究试图通过将地方领导纳入其中来解释这种争论。
研究方法
基于2005-2019年中国长江三角地区25个城市的数据集, 我们利用面板数据回归模型来研究地方官员在高铁-旅游关系中的调节作用。
研究结果
地方官员的任期在高铁开通对旅游业发展的影响中起着重要的调节作用。此外, 较短的官员任期会加强高铁连通对旅游业发展的促进作用。
原创性/价值
本文丰富了官员锦标赛理论的理论框架。此外, 我们的研究为更好地理解高铁与旅游的关系提供了一个新的视角。我们确定了地方领导人在高铁-旅游关系中的调节作用, 拓展了高铁-旅游关系的机制研究, 有助于解释高铁-旅游关系的争论。
Propósito
El tren de alta velocidad (TAV) afecta sustancialmente al desarrollo del turismo, pero este impacto sigue siendo algo controvertido. Este estudio explora el nexo entre el TAV y el turismo desde la perspectiva de la gobernanza local china. En el contexto del modelo de torneo de promoción en China, este estudio intenta explicar dicha controversia incluyendo a los líderes locales.
Diseño/metodología/enfoque
Basándonos en un conjunto de datos de 25 ciudades de la región china del delta del río Yangtze durante el periodo 2005-2019, utilizamos un modelo de regresión de datos de panel para examinar el papel moderador de los líderes locales en el nexo entre el TAV y el turismo.
Resultados
El mandato de los líderes locales tiene un papel moderador significativo en el impacto de la implementación del TAV en el desarrollo del turismo. Además, un mandato más corto de los líderes refuerza el impulso al desarrollo turístico del servicio de TAV.
Originalidad/Valor
Este trabajo enriquece el marco teórico de la teoría del torneo de líderes. Además, nuestro estudio proporciona una nueva perspectiva para entender mejor el nexo entre el TAV y el turismo. Identificamos el papel moderador de los líderes locales en el nexo TAV-Turismo y ampliamos la investigación del mecanismo de dicho nexo, lo que ayuda a explicar la controversia del nexo.
Details
Keywords
Shuo Wang and Bingwen Yan
China’s rural elderly care system faces significant challenges in addressing the needs of an ageing population, particularly in resource-limited areas. This study aims to…
Abstract
Purpose
China’s rural elderly care system faces significant challenges in addressing the needs of an ageing population, particularly in resource-limited areas. This study aims to critically examine the rural mutual aid elderly care model in China through the lens of active ageing principles. It explores how this model tackles elder care challenges in rural areas by emphasising health, participation and security, aiming to assess its effectiveness in reducing care costs while fostering self-reliance and mutual assistance.
Design/methodology/approach
A qualitative research methodology was used, focusing on document analysis to explore the rural mutual aid elderly care model within an active ageing framework. The study reviewed policy documents, academic literature and organisational records, using thematic analysis to understand the historical context, policy evolution and institutional support for this model.
Findings
The research identifies a significant shift from traditional passive care models to those grounded in active ageing principles. The rural mutual aid model, centring on health, participation and security, enables elderly individuals to engage in self-help and mutual assistance, thereby enhancing autonomy and reducing dependency. Key success factors include strong community networks and culturally resonant support systems. However, challenges such as resource limitations and regional disparities suggest areas for further improvement.
Research limitations/implications
The reliance on document analysis may not fully capture the experiences of elderly participants or account for regional variations in the model’s implementation. Future research could incorporate mixed methods, including interviews or case studies, for a more nuanced understanding of elderly care in rural China. The findings emphasise the need for scalable and adaptable policies to enhance the model’s effectiveness and support culturally appropriate care strategies.
Practical implications
The research presents significant implications for policymakers and practitioners regarding the rural mutual aid elderly care model. It emphasises the need for scalable policies that address resource limitations and enhance community engagement to improve care effectiveness. Key implications include promoting financial and social sustainability by fostering self-reliance among older adults, prioritising active ageing initiatives to enhance quality of life and community cohesion and adopting localised strategies that consider regional disparities. Moreover, these findings offer a blueprint for other countries facing similar ageing challenges, advocating for a culturally sensitive and community-driven approach to elderly care across East Asia.
Social implications
The study’s findings significantly impact how ageing is perceived and managed in rural Chinese communities. The shift from traditional, passive elderly care models to those grounded in active ageing principles reflects a societal transformation in valuing and supporting older adults. By promoting health, participation and security, the rural mutual aid elderly care model creates inclusive environments where the elderly actively contribute to their well-being and that of others. This approach challenges perceptions of ageing as a decline, fostering autonomy and meaningful engagement, ultimately reducing social isolation and enhancing cohesion through strengthened intergenerational relationships and shared responsibilities.
Originality/value
This study contributes to the literature by focusing on the rural mutual aid elderly care model in China through active ageing principles, addressing a notable gap in the non-Western application of these concepts. The findings offer valuable recommendations for policymakers and practitioners, emphasising community-driven approaches to ageing challenges in rural areas.
Details
Keywords
Chuanbao Nie, Bowen Fu and Qiang Gao
This paper aims to develop an efficient numerical method for nonlinear transient heat conduction problems with local radiation boundary conditions and nonlinear heat sources.
Abstract
Purpose
This paper aims to develop an efficient numerical method for nonlinear transient heat conduction problems with local radiation boundary conditions and nonlinear heat sources.
Design/methodology/approach
Based on the physical characteristic of the transient heat conduction and the distribution characteristic of the Green’s function, a quasi-superposition principle is presented for the transient heat conduction problems with local nonlinearities. Then, an efficient method is developed, which indicates that the solution of the original nonlinear problem can be derived by solving some nonlinear problems with small structures and a linear problem with the original structure. These problems are independent of each other and can be solved simultaneously by the parallel computing technique.
Findings
Within a small time step, the nonlinear thermal loads can only induce significant temperature responses of the regions near the positions of the nonlinear thermal loads, whereas the temperature responses of the remaining regions are very close to zero. According to the above physical characteristic, the original nonlinear problem can be transformed into some nonlinear problems with small structures and a linear problem with the original structure.
Originality/value
An efficient and accurate numerical method is presented for transient heat conduction problems with local nonlinearities, and some numerical examples demonstrate the high efficiency and accuracy of the proposed method.
Details
Keywords
Jiayu Qin, Nengxiong Xu and Gang Mei
In this paper, the smoothed point interpolation method (SPIM) is used to model the slope deformation. However, the computational efficiency of SPIM is not satisfying when modeling…
Abstract
Purpose
In this paper, the smoothed point interpolation method (SPIM) is used to model the slope deformation. However, the computational efficiency of SPIM is not satisfying when modeling the large-scale nonlinear deformation problems of geological bodies.
Design/methodology/approach
In this paper, the SPIM is used to model the slope deformation. However, the computational efficiency of SPIM is not satisfying when modeling the large-scale nonlinear deformation problems of geological bodies.
Findings
A simple slope model with different mesh sizes is used to verify the performance of the efficient face-based SPIM. The first accelerating strategy greatly enhances the computational efficiency of solving the large-scale slope deformation. The second accelerating strategy effectively improves the convergence of nonlinear behavior that occurred in the slope deformation.
Originality/value
The designed efficient face-based SPIM can enhance the computational efficiency when analyzing large-scale nonlinear slope deformation problems, which can help to predict and prevent potential geological hazards.
Details
Keywords
This paper aims to systematically visualize the structure and trends from 2005 to 2021, which will help scholars gain a deeper appreciation for existing studies and grasp future…
Abstract
Purpose
This paper aims to systematically visualize the structure and trends from 2005 to 2021, which will help scholars gain a deeper appreciation for existing studies and grasp future research possibilities and directions.
Design/methodology/approach
The approach is bibliometric, using VOSviewer and CiteSpace to analyze 765 journal articles and reviews from the Web of Science (WoS) and Scopus databases over the past 16 years.
Findings
There is considerable interest in urban tourism destination image (U-TDI), partly because of the role of image in promoting the economic development of urban tourism and the associated benefits to stakeholders. Most research output concerns China, the USA, Spain and the United Kingdom (UK); research in the USA context has had a particularly wide range of influence. Highly cited journals play a crucial role, while subject structure, key articles and high-frequency keywords indicate popular topics, sub-themes and development trends. Drawing on these findings, the authors identify four topics that deserve further study.
Originality/value
This systematic review will enhance understanding of U-TDI research and inform future research directions as well as highlighting the need to explore destination image in greater depth, it guides policymakers in the tourism industry seeking to develop city image.