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The purpose of this paper is to research on optimization of spindle bearing preload based on efficiency coefficient method and provide theoretical guidance for variable preload of intelligent spindle.

Based on an established thermo-mechanical coupling model of angular contact ball bearing with fix-position preload, temperature rise and axial stiffness of the bearing at different speeds and preload are analyzed, and life of the bearing is estimated by the improved L-P theory. The bearing temperature rise, axial stiffness and life data are standardized, and the preload is optimized by the efficiency coefficient method according to the requirements of operating conditions.

The optimized preload meets comprehensive requirements of the bearing temperature rise, axial stiffness and life under different operating conditions.

In the past studies, it is rarely reported that temperature rise, stiffness and life of the bearing under thermo-mechanical coupling effect are used as objective functions to optimize preload at different speeds.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-06-2020-0205/

Under fix-position preload, the high rotation speed of the angular contact ball bearing exacerbates the frictional heat generation, which causes the increase of the bearing temperature and the thermal expansion. The high rotation speed also leads to the centrifugal expansion of the bearing. Under the thermal and centrifugal effect, the structural parameters of the bearing change, affecting the mechanical properties of the bearing. The mechanical properties of the bearing determine its heat generation mechanism and thermal boundary conditions. The purpose of this paper is to study the effect of centrifugal and thermal effects on the thermo-mechanical characteristics of an angular contact ball bearing with fix-position preload.

Because of operating conditions, elastic deformation occurs between the ball and the raceway. Assuming that the surfaces of the ball and channel are absolutely smooth and the material is isotropic, quasi-static theory and thermal network method are used to establish the thermo-mechanical coupling model of the bearing, which is solved by Newton–Raphson iterative method.

The higher the rotation speed, the greater the influence of centrifugal and thermal effects on the bearing dynamic parameters, temperature rise and actual axial force. The calculation results show that the effects of thermal field on bearing dynamic parameters are more significant than the centrifugal effect. The temperature rise and actual axial force of the bearing are measured. Comparing the calculation and the experimental results, it is found that the temperature rise and the actual axial force of the bearing are closer to reality considering thermal and centrifugal effects.

In the past studies, the thermo-mechanical coupling characteristics research and experimental verification of angular contact ball bearing with fix-position preload are not concerned. Research findings of this paper provide theoretical guidance for spindle design.

This study aims to present a model and analysis of automotive body outer cover panels (OCPs) assembly systems to predict assembly variation. In the automotive industry, the OCPs assembly process directly influences the quality of the automobile body appearance. However, suitable models to describe variation propagation of OCPs assembly systems remain unknown.

An adaptive state space model for OCPs assembly systems is introduced to accurately express variation propagation, including variation accumulation and transition, where two compliant deviations make impacts on key product characteristics (KPCs) of OCP, and the impacts are accumulated from welding process to threaded connection process. Another new source of variation from threaded connection is included in this model. To quantify the influence of variation from threaded connection on variation propagation, the threaded connection sensitivity matrix is introduced to build up a linear relationship between deviation from threaded connection and output deviation in KPCs. This matrix is solved by homogeneous coordinate transformation. The final deviation of KPCs will be transferred to ensure gaps and flushes between two OCPs, and the transition matrix is considered as a unit matrix to build up the transition relationship between different states.

A practical case on the left side body structure is described, where simulation result of variation propagation reveals the basic rule of variation propagation and the significant effect of variation from threaded connection on variation propagation of OCPs assembly system.

The model can be used to predict assembly variation or potential dimension problems at a preliminary assembly phase. The calculated results of assembly variation guide designers or technicians on tolerance allocation, fixture layout design and process planning.

Between 1860 and 1945, the Chinese port city of Tianjin was the site of up to nine foreign-controlled concessions, functioning side by side. Rogaski defined it as a ‘hyper-colony’, a term which reflects Tianjin's socio-political intricacies and the multiple colonial discourses of power and space. This essay focuses on the transformation of the Tianjin cityscape during the last 150 years, and aims at connecting the hyper-colonial socio-spatial forms with the processes of post-colonial identity construction. Tianjin is currently undergoing a massive renovation program: its transmogrifying cityscape unveils multiple layers of ‘globalizing’ spatialities and temporalities, throwing into relief processes of power and capital accumulation, which operate via the urban regeneration's experiment. This study uses an ‘interconnected history’ approach and traces the interweaving ‘worlding’ nodes of today's Tianjin back to the global connections established in the city during the hyper-colonial period. What emerges is Tianjin's simultaneous tendency towards ‘world-class-ness’ and ‘China-class-ness’.

Since Cantonese opera was inscribed on UNESCO’s Representative List of the Intangible Cultural Heritage of Humanity in 2009, the Chinese government has carried out different policies to “develop” Cantonese opera in Guangzhou. Through state-initiated reforms, the local performing art was homogenized, institutionalized and nationalized in many ways. In this process, the government authorities took the lead and the Cantonese opera music community was not involved in the decision making of the future of their own tradition. This paper aims to discuss this issue.

Based on intensive fieldwork conducted in 2011, the paper examines the meaning of heritage to the local music community, as the art form was recognized by UNESCO in 2009. Apart from studying the policies made by the government, this paper looks into the socio-political impact brought to the Cantonese opera music community from a bottom-up perspective.

Cantonese opera performances in Guangzhou as well as performers’ own social life changed drastically in recent years. Musicians faced a dilemma of whether to follow the government’s market-oriented plan or to preserve their traditional lifestyle with their own initiative.

This paper reveals the voices of the “voiceless” music community and investigates the consequences resulted by the heritagization of the art form to the music community.

The ability to sift through the ever‐increasing amounts of information made available online to find quality and accurate data is becoming more important every day. Using credibility, accuracy, reasonableness, support, and uniqueness as criteria for Web site evaluation, the authors analyse five Web sites in an effort to determine the value and quality of the information. This article discusses the evaluation of Web sites dedicated to Chinese archaeology, and also points to six main characters of online resources for the subject area. In addition, questions are raised concerning the extent to which online Chinese archaeological resources can advance general awareness of the field and contribute to a growing body of knowledge. The authors hope this article sheds light on some of the challenges that need to be overcome when attempting to present this information to the global community.

In order to solve the current imbalance of academic resources within the discipline, this article builds a three-dimensional talent evaluation model based on the topic–author–citation based on the z index and proposes the ZAS index to evaluate scholars on different research topics within the discipline.

Based on the sample data of the CSSCI journals in the discipline of physical education in the past five years, the keywords were classified into 13 categories of research topics including female sports. The ZAS index of scholars on topic of female sports and so on was calculated, and quantitative indexes such as h index p index and z index were calculated. Comparative analysis of the evaluation effect was performed.

It is found that compared with the h index and p index, the z index achieves a better balance between the quantity, quality and citation distribution of scholars' results and effectively recognizes that the citation quality is higher and the number of citations of each paper is more balanced. In addition, compared to the z index, this article is based on a ZAS index model with an improved three-dimensional topic–author–citation relationship in research fields such as female sports.

It can identify some outstanding scholars who are engaged in small-scale or emerging topic research such as female sports and are excellent in different research areas. Talents create an objective and fair evaluation environment. At the same time, the ranking ability of ZAS indicators in the evaluation of talents is the strongest, and it is expected to be used in practical evaluations.