• Verification on Spray Simulation of a Pintle Injector for Liquid Rocket Engine

    分类: 动力与电气工程 >> 工程热物理学 提交时间: 2017-06-22 合作期刊: 《热科学学报》

    摘要: This paper demonstrates the plane stress state and the stress free thermo-elastic deformation of FGM thick plate under thermal loading. First, the Sneddon-Lockett theorem on the plane stress state in an isotropic infinite thick plate is generalized for a case of FGM problem in which all thermo-mechanical properties are optional functions of depth co-ordinate. The proof is based on application of the Iljushin thermo-elastic potential to displacement type system of equations that reduces it to the plane stress state problem. Then an existence of the purely thermal deformation is proved in two ways: first, it is shown that the unique solution fulfils conditions of simultaneous constant temperature and linear gradation of thermal expansion coefficient, second, proof is based directly on stress type system of equations which straightforwardly reduces to compatibility equations for purely thermal deformation if only stress field is homogeneous in domain and at boundary. Finally, couple examples of application to an engineering problem are presented.

  • Analysis of effects to scientific impact indicators based on the coevolution of coauthorship and citation networks

    分类: 图书馆学、情报学 >> 情报学 提交时间: 2024-04-19

    摘要: While computer modeling and simulation are crucial for understanding scientometrics, their practical use in literature remains somewhat limited. In this study, we establish a joint coauthorship and citation network using preferential attachment. As papers get published, we update the coauthorship network based on each paper’s author list, representing the collaborative team behind it. This team is formed considering the number of collaborations each author has, and we introduce new authors at a fixed probability, expanding the coauthorship network. Simultaneously, as each paper cites a specific number of references, we add an equivalent number of citations to the citation network upon publication. The likelihood of a paper being cited depends on its existing citations, fitness value, and age. Then we calculate the journal impact factor and h -index, using them as examples of scientific impact indicators. After thorough validation, we conduct case studies to analyze the impact of different parameters on the journal impact factor and h -index. The findings reveal that increasing the reference number N or reducing the paper’s lifetime θ significantly boosts the journal impact factor and average h -index. On the other hand, enlarging the team size m without introducing new authors or decreasing the probability of newcomers p notably increases the average h -index. In conclusion, it is evident that various parameters influence scientific impact indicators, and their interpretation can be manipulated by authors. Thus, exploring the impact of these parameters and continually refining scientific impact indicators are essential. The modeling and simulation method serves as a powerful tool in this ongoing process, and the model can be easily extended to include other scientific impact indicators and scenarios.