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This paper aims to design a single and double throat oil groove structure, which can reduce the drag torque of the wet clutch.

A three-dimensional simulation model was established herein using the computational fluid dynamics method. The influence of oil groove structure on the oil film flow field and the drag torque is obtained by a simulation.

Compared with the traditional radial oil groove, the results show that the single throat oil groove structure reduces the drag torque by about 24.59%; the double throat oil groove reduces the drag torque by about 47.27%. As the speed difference increases, the average temperature rise of the oil film of the double throat oil groove is 4°C lower than that of the single throat oil groove, indicating that it has good heat dissipation performance. The analysis results were verified by experimental results.

In this paper, the radial oil groove is taken as the reference object, and the structure of the oil groove is designed and improved. The simulation analysis and experiment verify the rule of the influence of the oil groove structure on the drag torque, which provides a new design idea for reducing the drag torque of wet clutch.

This study aims to use a bottom-up, inductive approach to derive destination image attributes from large quantities of online consumer narratives and establish a destination classification system based on relationships among attributes and places.

Content and social network analyses were used to explore the consumer image structure for destinations based on online narratives. Cluster analysis was then used to group destinations by attributes, and ANOVA provided comparisons.

Twenty-two attributes were identified and combined into three groups (core, expected, latent). Destinations were classified into three clusters (comprehensive urban, scenic and lifestyle) based on their network centralities. Using data on Chinese tourism, the most mentioned (core) attributes were determined to be landscape, traffic within the destination, food and beverages and resource-based attractions. Social life was meaningful in consumer narratives but often overlooked by researchers.

Destinations should determine into which category they belong and then appeal to the real needs of tourists. Destination management organizations should provide the essential attributes while paying greater attention to highlighting the destinations’ social life atmosphere.

This research produced empirical work on Chinese tourism by combining a bottom-up, inductive research design with big data. It divided the 49 destinations into three categories and established a new system based on rich data to classify travel destinations.

本研究旨在使用自下而上的归纳方法从大量的在线消费者的叙述中总结出目的地形象的属性, 并根据目的地形象的属性和地点之间的关系建立一个目的地分类系统。

首先通过内容分析方法和社会网络分析方法分析在线消费者的叙述数据得出目的地的消费者形象结构, 然后采用聚类分析方法按照属性对目的地形象进行分组, 并通过方差分析进行比较。

结果显示总结出22种属性, 并将其组合为三组(核心、预期和潜在)。目的地根据其网络中心度被分为三个集群(综合城市、风景和生活方式)。最常被提及的(核心)属性是景观、目的地的交通、食品和饮料以及资源型景点。在消费者的叙述数据中表明社会生活是有意义的, 但常常被研究人员忽视。

首先本研究通过将自下而上的归纳研究设计与大数据相结合对中国旅游业进行了实证研究。其次通过将49个旅游目的地分为三类以及基于大数据建立了一个新的旅游目的地分类系统。

旅游目的地应该明确自己属于哪一类目的地类型然后迎合游客的真正需求。DMOs应该提供旅游目的地的基本属性, 注重提升旅游目的地的社会生活氛围。

Se realizó un análisis de contenido en redes sociales para explorar la estructura de la imagen de los destinos por parte de los consumidores basándose en las descripciones en línea. A continuación, se empleó el análisis de clusters para agrupar los destinos por atributos, estableciendo comparaciones mediante el análisis ANOVA.

Los propósitos de esta investigación eran utilizar un enfoque ascendente e inductivo para obtener atributos de imagen de los destinos a partir de grandes cantidades de descripciones de consumidores en línea, y establecer un sistema de clasificación de destinos basado en las relaciones entre atributos y lugares.

Se identificaron 22 atributos que luego se agruparon en tres grupos (principales, esperados, latentes). Los destinos se clasificaron en tres grupos (urbano integral, paisajístico y de estilo de vida) en función de sus centralidades de red. Utilizando datos sobre el turismo chino, se determinó que los atributos (centrales) más mencionados eran el paisaje, el tráfico dentro del destino, la comida y las bebidas, y las atracciones basadas en los recursos. La vida social era importante en los comentarios de los consumidores, pero a menudo los investigadores la pasaban por alto.

Los destinos deberían determinar a qué categoría pertenecen y luego apelar a las necesidades reales de los turistas. Los DMO deberían proporcionar los atributos esenciales prestando mayor atención a resaltar el entorno de vida social de los destinos.

Esta investigación elaboró un trabajo empírico sobre el turismo chino combinando un diseño de investigación inductiva ascendente con big data. Dividió los 49 destinos en tres categorías y estableció un nuevo sistema basado en los grandes datos para clasificar los destinos turísticos.

This study aims to monitor and guide the assembly process. The operators need to change the assembly process according to the products’ specifications during manual assembly of mass customized production. Traditional information inquiry and display methods, such as manual lookup of assembly drawings or electronic manuals, are inefficient and error-prone.

This paper proposes a projection-based augmented reality system (PBARS) for assembly guidance and monitoring. The system includes a projection method based on viewpoint tracking, in which the position of the operator’s head is tracked and the projection images are changed correspondingly. The assembly monitoring phase applies a method for parts recognition. First, the pixel local binary pattern (PX-LBP) operator is achieved by merging the classical LBP operator with the pixel classification process. Afterward, the PX-LBP features of the depth images are extracted and the randomized decision forests classifier is used to get the pixel classification prediction image (PCPI). Parts recognition and assembly monitoring is performed by PCPI analysis.

The projection image changes with the viewpoint of the human body, hence the operators always perceive the three-dimensional guiding scene from different viewpoints, improving the human-computer interaction. Part recognition and assembly monitoring were achieved by comparing the PCPIs, in which missing and erroneous assembly can be detected online.

This paper designed the PBARS to monitor and guide the assembly process simultaneously, with potential applications in mass customized production. The parts recognition and assembly monitoring based on pixels classification provides a novel method for assembly monitoring.

This study aims to investigate the mechanism of the misinformation spread based on the elaboration likelihood model and the effects of four factors – emotion, topic, authority and richness – on the depth, breadth and structural virality of misinformation spread.

The authors collected 2,514 misinformation microblogs and 142,006 reposts from Weibo, used deep learning methods to identify the emotions and topics of misinformation and extracted the structural characteristics of the spreading network using the network analysis method.

Results show that misinformation has a smaller spread size and breadth than true news but has a similar spread depth and structural virality. The differential influence of emotions on the structural characteristics of misinformation propagation was found: sadness can promote the breadth of misinformation spread, anger can promote depth and disgust can promote depth and structural virality. In addition, the international topic, the number of followers, images and videos can significantly and positively influence the misinformation's spread size, depth, breadth and structural virality.

The influencing factors of the structural characteristics of misinformation propagation are clarified, which is helpful for the detection and management of misinformation.

This paper aims to explore the developing trend of higher pedagogy, to promote the research of higher pedagogy to be more canonical and scientific and to improve the higher education theory.

The utility research uses a method of quantitative study, namely “content analysis”, to estimate and analyze the higher education theory literature on ten dimensionalities which include theme, author, abstract, keywords, subject, proposing of the issue, definition of key terms, research methods, conclusion, reference and annotations from 1996 to 2006 in China.

The analysis of the selected 250 academic theses and reports in the field of higher education shows that academic research and theoretical standard have been improved, meanwhile academic criterion have been formed by degrees in higher pedagogy within ten years. At the same time, there are still some problems in the papers and reports the authors have selected such as title, key words, proposing of the issue, researching method and conclusion.

This paper sums up the trend of research on higher education in China for the past ten years, and points out the problems in this trend and then proposes ways to improve the research of higher education in China.

Oil-free heat pumps that use the system refrigerant gases as lubricants are preferred for thermal management in future space applications. This study aims to numerically and experimentally investigate the static performance of externally pressurized thrust bearings lubricated with refrigerant gases.

The refrigerant gases R22, R410A and CO₂ were chosen as the research objects, while N₂ was used for comparison. Computational fluid dynamics was used to solve the full 3 D Navier–Stokes equations to determine the load capacity, static stiffness and static pressure distribution in the bearing film. The numerical results were experimentally verified.

The results showed that the refrigerant-gas-lubricated thrust bearings had a lower load capacity than the N2-lubricated bearings, but they presented a higher static stiffness when the bearing clearance was less than 9 µm. Compared with the N2-lubricated bearings, the optimal static stiffness of the R22- and CO2-lubricated bearings increased by more than 46% and more than 21%, respectively. The numerical and experimental results indicate that a small bearing clearance would be preferable when designing externally pressurized gas thrust bearings lubricated with the working medium of heat pump systems for space applications.

The findings of this study can serve as a basis for the further investigation of refrigerant gases as lubricants in heat pump systems, as well as for the future design of such gas bearings in heat pump systems for space applications.

As the crucial support component of the propeller power system, the reliability of the operation of submersible pumps is influenced by the lubrication performance of water-lubricated thrust bearings. When the water-lubricated thrust bearings are under start-stop or heavy load conditions, the effect of surface morphology is crucial as the mixed lubrication regime is encountered. This paper aims to develop one mixed lubrication model for the water-lubricated thrust bearings to predict the effects of surface skewness, kurtosis and roughness orientation on the loading carrying capacity and tribological behavior.

This paper developed one improved mixed lubrication model specifically for the water-lubricated thrust bearing system. In this model, the hydrodynamic model was improved by using the height of the rough surface and its probability density function, combined with the average flow model. The asperity contact model was improved by using the equation for the Pearson system of frequency curves to characterize the non-Gaussian aspect of surface roughness distribution.

According to the results, negative skewness, large kurtosis and lateral surface pattern can improve the tribological performance of water-lubricated thrust bearings. Optimizing the surface morphology is a reasonable design method that can improve the performance of water-lubricated thrust bearings.

In this paper, one mixed lubrication model specifically for the water-lubricated thrust bearing with the effect of surface roughness into consideration was developed. Based on the developed model, the effect of surface morphology on tribological behavior can be evaluated.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-08-2023-0247/

The purpose of this paper is to enhance the accuracy as well as efficiency of high-speed machining, avoid the speed fluctuation caused by acceleration/deceleration (ACC/DEC) and increase the smoothness of feedrate in continuous corners or curves machining. The Hbot kinematic system was analyzed and combined with fused deposition modeling-based (FDM) additive manufacturing (AM) technology. Then a real-time adaptive look-ahead speed control algorithm was proposed.

To validate the performance of Hbot kinematic system and the proposed speed control algorithm, the positioning accuracy of Hbot and cross structure was compared. Also, the experimental verification was conducted among FDM based 3-D printer with cross structure as well as open source speed control algorithm (FDM with cross-OS), cross structure and the proposed speed control algorithm (FDM with cross-PS) and Hbot structure, as well as the proposed speed control algorithm (FDM with Hbot-PS), respectively.

The results indicate that the Hbot kinematic system leads to the high stability of positioning accuracy due to the small motion inertia. Furthermore, the experimental verification shows that the efficiency, printing precision and surface finish of models for FDM with Hbot-PS are obviously higher than that for FDM with cross-PS as well as FDM with cross-OS, while FDM with cross-OS shows the worst performance. The contribution of Hbot kinematic system and the proposed speed control algorithm to FDM based AM technology was validated by this work.

The Hbot kinematic system and proposed speed control algorithm have the important implication of improving the accuracy of FDM machines, especially in the low-price range segment. Also, this work can help future system developers show a possible way of tackling the motion inertia problem.

The study of Hbot kinematic system and proposed algorithm are expected to advise the current research for improving the accuracy as well as the efficiency of FDM-based AM technology.

The Purpose of this research is to initiate the “Fourth Industrial Revolution” by using the Internet of things (IoT), which can be applied to flammable gas condition monitoring and detection of gas leakage and activate fire extinguisher in case of fire accidents. Liquefied petroleum gas (LPG) leakage and explosions cause many injuries and death each year. By developing an automated and remote LPG ppm condition monitoring and fire extinguisher activation system with the help of a cyber-physical system, the rate of accidents and injuries can be reduced to a significant amount.

The IoT enabled the sensors to transmit LPG concentration value reading to a mobile app or cloud server and control actuators by connecting all in the same network. In case of a fire accident, the solenoid valve automatically or can be activated by an android application manually, which will be pre-installed in mobile phones. Another advantage of this system is that the gas cylinder or flammable particle source can be closed by closing the solenoid valves attached to their outlets. The first challenge of Industry 4.0 is to develop a cyber-physical system where all physical entities can be monitored and controlled over the internet or another way remotely or from a single point.

This fire extinguisher system can be used everywhere and in all types of firefighting because all types of fire extinguishers are commercially available in cylinders where solenoid valves can be used instead of conventional valves. This system will reduce human effort in the fire safety system and reduce the number of losses owing to fire accidents by taking all actions automatically and from a safe distance. The reliability analysis of this system indicated that the working condition for the best outcome is 20–35°C and the baud rate of the controller should be 11.5 kHz.

The study of pieces of the literature summarizes that this work is unique in terms of the application of Industry 4.0 in the fire safety system and reliability analysis of this system helped to determine the operating condition for the best performance of this system. Some LPG condition monitoring system was developed using IoT before but had many limitations such as working capability during load shading or emergency cases.

A multi-laser sensors-based measurement instrument is proposed for the measurement of geometry errors of a differential body and quality evaluation. This paper aims to discuss the aforementioned idea.

First, the differential body is set on a rotation platform before measuring. Then one laser sensor called as “primary sensor”, is installed on the intern of the differential body. The spherical surface and four holes on the differential body are sampled by the primary sensor when the rotation platform rotates one revolution. Another sensor called as “secondary sensor”, is installed above to sample the external cylinder surface and the planar surface on the top of the differential body, and the external cylinder surface and the planar surface are high in manufacturing precision, which are used as datum surfaces to compute the errors caused by the motion of the rotation platform. Finally, the sampled points from the primary sensor are compensated to improve the measurement accuracy.

A multi-laser sensors-based measurement instrument is proposed for the measurement of geometry errors of a differential body. Based on the characteristics of the measurement data, a gradient image-based method is proposed to distinguish different objects from laser measurement data. A case study is presented to validate the measurement principle and data processing approach.

The study investigates the possibility of correction of sensor data by the measurement results of multiple sensors to improving measurement accuracy. The proposed technique enables the error analysis and compensation by the geometric correlation relationship of various features on the measurand.

The proposed error compensation principle by using multiple sensors proved to be useful for the design of new measurement device for special part inspection. The proposed approach to describe the measuring data by image also is proved to be useful to simplify the measurement data processing.