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Random point-contact between the space bearing retainer and the rolling elements may cause wear of the space bearing retainer. The paper aims to clarify the friction and wear behaviors of polyimide bearing retainer under point-contact condition.

Space bearing retainers were cut into flat specimens and the tribological behaviors of the specimens were studied under point-contact condition using a friction and wear testing machine. Different sliding velocities and normal loads were used to simulate the running state of space bearing retainer. The wear behaviors of the space bearing retainer were analyzed by SEM and white light interferometer.

The friction coefficient of the polyimide composites decreased with increase in sliding velocity from 1  to 5 mm/s. Moreover, with increase in sliding velocity and normal load, the wear rate of the polyimide composites decreased and increased, respectively. Moreover, the wear behaviors of the polyimide composites were mainly determined by the combined actions of ploughing friction and adhesive friction. The lubricating properties of transfer film and wear debris were limited under point-contact condition.

The paper includes implications for the understanding of the wear mechanism of the polyimide composites space bearing retainer under point-contact condition and then to optimize space bearing retainer materials further.

Under point-contact condition, wear debris can hardly participate in the friction process because of limited contact area. Consequently, the wear debris has limited impact on the wear process to decrease the friction and wear.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-01-2020-0017/

The purpose of this paper is to investigate the evolution of the permeability of spherical packing during cold compaction by pore-scale modeling.

The discrete element method (DEM) is used to generate spherical packing structure under different compressive pressures and the Lattice Boltzmann method (LBM) is adopted to calculate the permeability of each spherical assembly.

It is found that the decrease of the porosity is the main reason of the reduction in permeability in the initial compression stage, but its influence becomes insufficient in the late compression stages. Besides, two empirical formulas are obtained, which describe the relation between the permeability and the equivalent mean diameter and the variation of normalized permeability with compressive pressure, respectively.

In this study, the authors study the spherical particles and ignore the non-spherical effects. Besides, the classical contact model, the linear-spring-damping model, is used in DEM, so the plastic deformation cannot be considered.

The DEM and the LBM are well combined to study the compaction effects on permeability of spherical packing. Two simple expressions of the spherical packing structure with uniform diameter distribution are given for the first time.

Nowadays, a large amount of data related to aero engine in various types can be created in a single day and it is very important to well organize and store these data. The paper aims to discuss this issue.

This paper puts forward the problem of data management with the fast development of aero engine and sets the compression system as an example to see the inner relationships of data from the initial design procedure to the final operation and maintenance part. There are five principles, namely digitization, accuracy, normative, integrality and validity, involved in managing the data effectively.

These data resources arranged according to the five principles can be well organized and better used.

At the end, the top design of aero engine data sharing platform is investigated and five layers including data layer, data access layer, communication layer, business logic layer and application layer are designed and presented to support the platform.

The corrosion behaviour of titanium alloy surface when fluid with different flow rates flows through welded joints with different residual heights was explored.

The experiment uses a combination of array electrodes and simulation.

It is found that when the weld reinforcement exists, the corrosion tendency of both ends of the weld metal is greater than that of other parts of the welded joint due to the influence of high turbulence kinetic energy and shear stress. The presence of weld reinforcement heights makes the fluid behind it fluctuate greatly. The passivation films of both the base metal (BM) at the rear and the heat-affected zone (HAZ) are more prone to corrosion than those of the front BM and HAZ, and the passivation film is rougher.

The combination of test and simulation was used to explore the influence of electrochemical and hydrodynamic factors on the corrosion behaviour of titanium alloy-welded joints when welding residual height existed.

The purpose of this paper is to conduct a comprehensive study on building, fire and evacuation, so as to effectively improve the efficiency of building fire evacuation and the management level of fire evacuation site. Make up for the difficulties of BIM technology in effectively connecting building information and fire data.

First, this paper establishes a fire model and an evacuation model based on BIM information. Then, the safety index (SI) is introduced as a comprehensive index, and the IRI is established by integrating the SI function to evaluate the safety of evacuation routes. Based on these two indices, the IRI-based fire evacuation model is established.

This study offers an Improved Risk Index (IRI)-based fire evacuation model, which may achieve effective evacuation in fire scenes. And the model is verified by taking the fire evacuation of a shopping center building as an example.

This paper proposes a fire evacuation principle based on IRI, so that the relevant personnel can comprehensively consider the fire factors and evacuation factors to achieve the optimization of building design, thereby improving the fire safety of buildings.

The relationship between sex and tourism remains ambiguous in the tourism literature. Few studies have examined the underlying motivations behind sex-driven travel, and little is known about factors inhibiting tourists' procurement of commercial sex when traveling. Therefore, this study explored male Chinese tourists' perceived constraints during decision-making and developed a comprehensive scale to assess constraints to commercial sex consumption overseas.

Data were obtained from male Chinese tourists purchasing commercial sex while traveling overseas. This study involved a four-stage process as recommended by Churchill (1979) for scale development research. In Stage 1, preliminary items were generated through a comprehensive review of the constraints literature and in-depth interviews with 16 sex tourists, which generated an initial 26 items. During the second stage to purify the measurement items, six items were eliminated, resulting in 20 items. Stage 3 involved exploratory factor analysis (N = 275) to extract the scale's underlying factor structure. Results revealed a five-factor structure with sufficient evidence of internal reliability given Cronbach's alpha coefficients between 0.722 and 0.843. The final stage included confirmatory factor analysis (N = 259) to verify the scale's reliability and validity.

Ultimately, 20 items were developed to measure sex tourists' perceived constraints toward engaging in commercial sex services overseas based on five factors: structural constraints, intrapersonal constraints, interpersonal constraints, value conflicts and service supply–related constraints.

This study advances the scope of sex tourism research by verifying how these five constraints are independent, generalized and can influence the procurement of sexual services overseas. This study is the first in sex tourism research to explore the difficulties facing sex tourists. Results offer marketers important insight on how to better address these constraints while providing a safe and legal sex tourism experience.

The 2019 novel coronavirus (COVID-19) outbreak is projected to have adverse consequences on the global tourism and hospitality industry. This paper aims to examine how the outbreak may alter Chinese tourists’ lifestyle choices, travel behaviour and tourism preferences in the short and long term.

This paper is based on the synthesis of news broadcasted by several media outlets to be supported by an overview of the related literature on tourism marketing, tourism management and tourist behaviour. The authors’ experiences investigating trends in tourism and hospitality at the local and international level have also contributed to the study.

This paper predicts that COVID-19 will likely affect Chinese travellers’ consumption patterns, such as the growing popularity of free and independent travel, luxury trips and health and wellness tourism. New forms of tourism including slow tourism and smart tourism may also drive future tourism activities. Such changes are likely to force businesses to reconsider their service designs and distribution channels.

While Chinese and other potential visitors rethink how they travel, professionals, too, should reflect upon how to bring positive or negative changes to the tourism industry following this pandemic. Subsequent research should also consider how to mitigate the effects of similar public health crises in the future.

Recommendations for industry practitioners and policymakers focus on tailoring travel arrangements to tourists’ backgrounds. The suggestions may help to alleviate outbreak-related stress, offer travellers newly enriching experiences and partially mitigate the effects of COVID-19 on the tourism and hospitality industry. These recommendations can also apply more broadly to global tourist markets.

The COVID-19 outbreak has already brought significant impacts to nearly every society and industry. Tourism scholars and practitioners should carefully consider this tragedy and how it may inform industry and social practices. This and other public health crises represent sterling opportunities to view the industry holistically in terms of its effects on the environment, climate and travellers themselves.

This paper presumably represents a frontier study, critically examining the possible impacts of COVID-19 on Chinese travellers’ consumption patterns and how the tourism and hospitality industry may respond to such changes in the future.

预计2019年新型冠状病毒（COVID-19）爆发将对全球旅游和酒店业产生不利影响。本文预测, COVID-19可能会影响中国旅客的消费方式, 例如自由行, 豪华旅行以及健康与养生旅游的普及。包括慢速旅游和智能旅游在内的新型旅游形式也可能推动未来的旅游活动。这种变化可能促使企业重新考虑其服务设计和分销渠道。针对行业从业者和政策制定者的建议着重于根据游客的背景和需求量身定制旅行安排。我们的建议可能有助于减轻与疫情暴发导致的压力, 为旅行者提供全新的丰富体验, 并从一定程度减轻COVID-19对旅游业和酒店业的影响。这些建议还可以更广泛地应用于全球旅游市场。

COVID-19, 生活方式 旅游行为 灾后 集体主义倾向 中国

El impacto del COVID-19 se prevé importante en la actividad turística global y en la industria de la hostelería. Este artículo predice que el COVID-19 afectará con probabilidad alta los patrones de consumo de los viajeros chinos, incluyendo los cada vez más populares viajes comprados directamente por los consumidores chinos, en el segmento del lujo, y el turismo de salud y belleza. Nuevas formas de turismo, incluyendo el slow tourism, y el turismo responsable pueden convertirse en importantes tendencias de futuro igualmente. Dichos cambios llevarán con cierta seguridad a la industria a reconsiderar y adaptar su oferta de servicios en este sector, en particular su diseño y los canales de distribución utilizados. Las recomendaciones para la industria y los responsables de la política turística se alinean con una mayor proximidad de la oferta a los gustos cambiantes del consumidor. Dichas acciones ayudarán a reducir fricciones y fallos en la definición del negocio turístico, ofreciendo a los viajeros nuevas y enriquecedoras experiencias, así como podrán mitigar en parte los efectos adversos estimados del COVID-19, los cuales son relevantes a día de hoy. Así mismo, dichas recomendaciones son aplicables de una manera más global a la industria del turismo y la hospitalidad en el mercado mundial.

COVID-19, Estilo de vida, Conducta del viajero, Post-desastre, Orientacion collectivista, China

A zero-day vulnerability is a complimentary ticket to the attackers for gaining entry into the network. Thus, there is necessity to device appropriate threat detection systems and establish an innovative and safe solution that prevents unauthorised intrusions for defending various components of cybersecurity. We present a survey of recent Intrusion Detection Systems (IDS) in detecting zero-day vulnerabilities based on the following dimensions: types of cyber-attacks, datasets used and kinds of network detection systems.

Purpose: The study focuses on presenting an exhaustive review on the effectiveness of the recent IDS with respect to zero-day vulnerabilities.

Methodology: Systematic exploration was done at the IEEE, Elsevier, Springer, RAID, ESCORICS, Google Scholar, and other relevant platforms of studies published in English between 2015 and 2021 using keywords and combinations of relevant terms.

Findings: It is possible to train IDS for zero-day attacks. The existing IDS have strengths that make them capable of effective detection against zero-day attacks. However, they display certain limitations that reduce their credibility. Novel strategies like deep learning, machine learning, fuzzing technique, runtime verification technique, and Hidden Markov Models can be used to design IDS to detect malicious traffic.

Implication: This paper explored and highlighted the advantages and limitations of existing IDS enabling the selection of best possible IDS to protect the system. Moreover, the comparison between signature-based and anomaly-based IDS exemplifies that one viable approach to accurately detect the zero-day vulnerabilities would be the integration of hybrid mechanism.

This study developed an extended model of self-congruity by integrating destination image, destination personality, self-congruity, revisit intention and gender.

Surveys were conducted with 645 Chinese tourists visiting New Zealand. Partial least squares structural equation modelling (PLS-SEM) was performed to estimate linkages between destination image, destination personality, self-congruity and revisit intention. To compare effects on revisit intention across male and female Chinese tourists, PLS-Henseler's multigroup analysis and PLS-permutation test were conducted to analyse gender as a moderator in the proposed framework.

Our results revealed positive direct effects among destination image, destination personality, self-congruity and revisit intention. Our findings indicated a highly significant difference in the effects of destination personality on ideal self-congruity across male and female Chinese tourists. The association between destination image and self-congruity identified through this model represents a crucial contribution to the tourism literature. This study also enriches tourism research by comparing male and female Chinese tourists' intentions to revisit New Zealand, having identified crucial heterogeneity within female tourists.

The practical implications from our research can improve destination marketing organization (DMO) officials' awareness of one-time and repeat Chinese tourists' experiences, which strongly trigger subsequent visits.

This paper is the first to examine the direct correlations among destination image, destination personality, self-congruity and revisit intention by considering whether gender might moderate these factors. Our study innovatively adopted PLS-SEM along with several advanced analytical approaches, such as multigroup analysis (MGA) of women and men, to examine our research model.

The novel structures and properties of nanostructure and nanomaterials give people perfect artistic expression of feeling and sense, then the nanoart discipline is developed and is closely related on the nanotechniques. The many achieved novel nanostructures with strong anti-corrosion prepared by the anodization have been reviewed. The paper would raise public awareness of nanotechnology, nanomaterial and their impact on our lives.

Anodization is a very effective and simple technique to form various nanostructures of metal oxide. It includes hard anodization, mild anodization and pulse anodization. Many measures have been introduced anodization process to improve the quality of formed nanostructure and enhance its properties, such as anti-corrosion.

The formation mechanism of anodic aluminum oxide (AAO) by using the mild, hard and pulse anodization has been discussed. The pretexture process and many other measures have been taken in mild and hard anodization to improve the regularity of pore array and greatly accelerate the formation rate of AAO. The pulse anodization has been used to prepare the multilayer Y-branched AAO film, which exhibits steady rich and vivid structure colors and gives a very good artistic expression. Furthermore, many other metal oxide nanostructures such as TiO₂ and CuO have also been fabricated using the anodization techniques.

Various nanostructures of metal oxide prepared by anodization have been reviewed and are itself a perfect artwork in mesoscale. Also, many nanostructures have exhibited steady, rich and vivid structure colors and give people a very good artistic expression.