Properties Of Molecular Topological Index As Well As The Applications In Oil Film Pressure Test

The changing of the environmental temperature has been always considered in running machines and all kinds of equipment. Through the lubricating oil film pressure test can determine the lubricating oil film and observed the rule of oil film pressure changes. If the oil film formed bad, it will affect the normal operation of instruments and equipments, even damage the instruments and equipments. Low temperature lubrication experiments must be done for machines and equipment running in low temperature environment. Molecular topological indices are functions defined on molecule structure of the compound which is closely related to the physical and chemical features of the corresponding compound. As a kind of Molecular topological indices, Balaban index was used to predict the melting point of the lubricating oil.In this paper we mainly work on the followings:(1) By researching in two kinds of Molecular topological indices which are Balaban index and Sum-Balaban index, we obtained the extreme values of the two indices on bicyclic graphs and cactus graphs. Moreover, the extremal graphs were also obtained. The scrambling index and m-competition index of primitive digraphs were also considered in this paper. (2) In applications, we used linear regression to find a linear model which predicts the melting point of normal alkanes C14-C19 respect to temperatures by using Balaban center index and Balaban index. By designing a special kind testing experiments for sliding bearing oil film pressure test, using dynamic pressure bearing test rig and selecting normal alkanes C14 as lubricants, we observed the oil film pressure curve under the following conditions:the load of 1078.7N, speed of 307 r/min, temperature for 4-11?We obtained a linear model from Molecular topological indices and concluded that the model was precise in predicting the melting point of compounds, realized the high precision of prediction to alkanes lubricating oil melting point. By fitting equation, we selected the suitable lubricating oil for the tesr, and designed an experiment of dynamic bearing oil film pressure test, the experiment can be detected the rule of oil film pressure changes under the condition of lubricating oil temperature near the melting point which has universal significance. In low temperature environment, the performance of the lubricating oil and provided a new research idea.