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The purpose of this paper is to analyze the micro-motion of the cylinder block.

Based on the elasto-hydrodynamic lubrication, a numerical model for the cylinder block/valve plate interface is proposed, with consideration of the elastic deformations, the pressure-viscosity effect and asperity contacts. The influence-function method is applied to calculating the actual deformations of the cylinder block and the valve plate. The asperity contact model simplified from Greenwood assumption is introduced into the numerical model. Furthermore, the relationship between the micro-motion and the operating condition, the sealing belt width is discussed, respectively.

The results show an increase in the discharge pressure causes the tilt state and the vibrating motion getting worse, which can be eased by improving the rotational speed, the sealing belt width and the ratio of external and internal sealing belt width.

The proposed research can provide a theoretical reference for the optimizing design of cylinder block/valve plate pair.

The incorporation of phosphide additives is regarded as a highly effective strategy for enhancing the lubricative qualities of base oils. This study aims to assess the lubrication behavior and efficacy of various phosphide additives in polyethylsiloxane (PES) through the employment of the Schwingum Reibung Verschleiss test methodology, across a temperature range from ambient to 300°C.

PES demonstrated commendable lubrication capabilities within the Si3N4/M50 system, primarily attributable to the Si-O frictional reaction film at the interface. This film undergoes disintegration as the temperature escalates, leading to heightened wear. Moreover, the phosphide additives were found to ameliorate the issues encountered by PES in the Si3N4/M50 system, characterized by numerous boundary lubrication failure instances. A chemical film comprising P-Fe-O was observed to form at the interface; however, at elevated temperatures, disintegration of some phosphide films precipitated lubrication failures, as evidenced by a precipitous rise in the coefficient of friction.

The results show that a phosphide reactive film can be formed and a reduction in wear rate is achieved, which is reduced by 64.7% from 2.98 (for pure PES at 300°C) to 1.05 × 10^–9 μm³/N m (for triphenyl phosphite at 300°C).

The data derived from this investigation offer critical insights for the selection and deployment of phosphide additives within high-temperature lubrication environments pertinent to PES.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-04-2024-0139/

Online grocery stores are facing challenges. The intense competition in the online grocery market has driven companies to seek technological innovation. Moreover, the operations of online grocery stores on both the supply and demand sides are not sufficiently meeting the requirements of consumers and managers. The powerful capabilities of the Generative Pre-Trained Transformer (GPT) technology align with the needs of online grocery stores for innovation and upgrading. This study uniquely leverages GPT’s advanced natural language processing, adaptive learning and generative capabilities to analyze and optimize the online grocery supply chain competition in ways not possible with traditional analytical tools.

This paper constructs a Stackelberg game model, comprising a secondary supply chain consisting of a supplier who provides products and a retailer who sells them. This study explores the impact of GPT technology on online grocery store operations from the demand side and supply side, specifically including the value of service information, demand information and information-sharing behavior.

The findings reveal several vital conclusions: (1) On the demand side, the service information plays a crucial role in enhancing service levels and increasing consumer demand; (2) On the supply side, demand information provides positive incentives for retailers and suppliers and (3) Information-sharing behaviors can lead to cooperative relationships between upstream and downstream supply chain members, significantly increasing their respective service levels. This study not only explores the impact of GPT on the online grocery supply chain but also presents a rigorous framework for validating GPT-generated insights, ensuring the reliability of our findings.

This study provides valuable insights into a promising field. It employs game theory to analyze the impact of GPT technology on the overall operation of the online grocery supply chain and the market strategy of online grocery stores.

The purpose of this paper is to explore the possibility of combining additive manufacturing (AM) with topology optimization to generate support structures for addressing the challenging overhang problem. The overhang problem is considered as a constraint, and a novel algorithm based on continuum topology optimization is proposed.

A mathematical model is formulated, and the overhang constraint is embedded implicitly through a Heaviside function projection. The algorithm is based on the Solid Isotropic Material Penalization (SIMP) method, and the optimization problem is solved through sensitivity analysis.

The overhang problem of the support structures is fixed. The optimal topology of the support structures is developed from a mechanical perspective and remains stable as the material volume of support structures changes, which allows engineers to adjust the material volume to save cost and printing time and meanwhile ensure sufficient stiffness of the support structures. Three types of load conditions for practical application are considered. By discussing the uniform distributive load condition, a compromise result is achieved. By discussing the point load condition, the removal work of support structures after printing is alleviated. By discussing the most unfavorable load condition, the worst collapse situation of the printing model during printing process is sufficiently considered. Numerical examples show feasibility and effectiveness of the algorithm.

The proposed algorithm involves time-consuming finite element analysis and iterative solution, which increase the computation burden. Only the overhang constraint and the minimum compliance problem are discussed, while other constraints and objective functions may be of interest.

Compared with most of the existing heuristic or geometry-based support-generating algorithms, the proposed algorithm develops support structures for AM from a mechanical perspective, which is necessary for support structures particularly used in AM for mega-scale construction such as architectures and sculptures to ensure printing success and accuracy of the printed model.

With the rapid development of AM, complicated structures result from topology optimization are available for fabrication. The present paper demonstrates a combination of AM and topology optimization, which is the trend of fabricating manner in the future.

This paper remarks the first of attempts to use continuum topology optimization method to generate support structures for AM. The methodology used in this work is theoretically meaningful and conclusions drawn in this paper can be of important instruction value and practical significance.

The purpose of this paper is to investigate the effects of chief executive officer (CEO) international work experience, functional background and career concerns on managerially-distorted investment decisions.

This paper focuses on S&P 500 publicly held US manufacturing companies during the period from 2009 to 2012. The data related to the CEOs’ international experience and their functional background experience are manually collected from Business Week’s Corporate Elite. Financial data is retrieved from COMPUSTAT database. The data for CEO tenure and age are retrieved from the ExecuComp database. Besides ordinary least squares regression, this paper conducts two-stage least squares regression analysis. Endogeneity and additional tests are also considered in this paper.

The findings show that CEO international work experience may not reduce under-investment, but it may exacerbate over-investment. CEO throughput functional background may exacerbate under-investment, but it may not reduce over-investment. Furthermore, CEO career concerns are useful in reducing the inefficient investments caused by international work experience and throughput functional background. These results remain similar when potential self-selection bias, as well as alternative measures of career concerns and investment efficiency, are considered.

This paper contributes to the existing literature in the following ways: first, while a significant amount of attention has been paid to how investment decisions are affected by financial reporting quality and material internal control weaknesses, there has been little evidence accumulated related to how managers’ international experience, professional background and career concerns affect investment inefficiency. The authors attempt to fill this gap. Second, the authors manually collect the international experience and functional backgrounds of CEOs working for S&P 500 US manufacturing companies. This unique data set makes it possible to complement previous studies by investigating the effects of managerial international experience and functional background on investment behavior. Finally, previous theoretical studies have long recognized that managers’ career concerns affect their corporate investment decisions. These studies suggest that young CEOs have a greater incentive to signal their abilities by adopting more active and possibly riskier investment strategies, thus raising the moral hazard problem with regard to firm investments. The authors enrich these studies by showing that work experience alleviates the moral hazard problem with respect to young CEOs’ investment decisions.

In the era of the digital economy, higher demands are placed on versatile talents, and the cultivation of students with innovative and entrepreneurial abilities has become an important issue for the further development of higher education, thus leading to extensive and in-depth research by many scholars. The study summarizes the characteristics and patterns of dual-innovation education at different stages of development, hoping to provide a systematic model for the development of dual-innovation education in China and make up for the shortcomings.

This paper uses Citespace software to visualize and analyze the relevant literature in CNKI and Web of Science databases from a bibliometric perspective, focusing on quantitative analysis in terms of article trends, topic clustering, keyword co-linear networks and topic time evolution, etc., to summarize and sort out the development of innovation and entrepreneurship education research at home and abroad.

The study found that the external characteristics of the literature published in the field of bi-innovation education in China and abroad are slightly different, mainly in that foreign publishers are more closely connected and have formed a more stable ecosystem. In terms of research hotspots, China is still in a critical period of reforming its curriculum and teaching model, and research on the integration of specialization and creative education is in full swing, while foreign countries focus more on the cultivation of students' entrepreneurial awareness and the enhancement of individual effectiveness. In terms of cutting-edge analysis, the main research directions in China are “creative education”, “new engineering”, “integration of industry and education” and “rural revitalization”.

Innovation and entrepreneurship education in China is still in its infancy, and most of the studies lack an overall overview and comparison of foreign studies. Based on the econometric analysis of domestic and foreign literature, this paper proposes a path for domestic innovation and entrepreneurship education reform that can make China's future education reform more effective.

The purpose of this paper is to comparatively investigate the microstructure and interfacial intermetallic compound (IMC) layer of Cu/SACPG/Ni and Cu/SAC0307/Ni solder joints after thermal aging.

The specimens were thermally aged at 150°C for 0, 24, 168 and 500 h. The microstructure and morphology of the interface IMC layer were observed by means of scanning electron microscope. The IMCs and the solder bump surface were analyzed by EDS. Moreover, the thickness of IMC layer was measured by using the image analysis software.

The morphology of IMC of Cu/SAC0307/Ni solder joint was consistent with that of the Cu/SACPG/Ni joint, which indicates that the addition of P and Ge had little effect on the IMC formation. The needle-like (Cu,Ni)6Sn5 was formed at the interface of solder/Ni solder joints. Meanwhile, the tiny particles inferred as Ag3Sn phase attached to the surface of (Cu,Ni)6Sn5. The growth rate of IMC layer of the Cu/SACPG/Ni joint was smaller than that of Cu/SAC0307/Ni joint with aging time increasing, which means the addition of trace P and Ge can slightly suppress the diffusion rate of the interfacial IMC.

There are no previous studies on the formation mechanism of the IMC layer of SAC0307 solder alloys with P and Ge addition.