Study On The Mechanical Model Of Bacteria Adhesion On Banknote Surface

With the continuous improvement of the social production, living and building and human material and spiritual civilization, it is resulted in a series of environmental problems, in which the hazards of the bacteria, viruses and other microorganisms to human health are more and more serious. Medical research shows that paper money not only spreads the carrier of many diseases, but also causes many diseases culprit. Moreover, people’s health awareness is expanding, and the health, security requirements of the surrounding environment are also increasing.Notes are the necessities of daily life, and the disinfection of notes becomes an object of interest. To solve the notes disinfection, the research of bacterial adhesion, removal and prevention is very important. To solve the problem of the bacteria adhesion, first of all, we must in understand the mechanism of bacteria adhesion on the surfaces of the notes.The main research contents and conclusions are as follows:(1)By retrieving a large number of domestic and foreign literature about bacterial adhesion mechanics, the results of these studies were summarized and analyzed. Based on these, the research orientation and work that required were put forward for bacterial adhesion.(2)Comprehensive summary and analyze the distribution of the bacteria on the surface of notes, and the amount of bacteria on the surface changes significantly with the seasons, which also has a relationship with the denomination banknotes. Through electron microscopy, the bacterial adhesion was positively correlated with the surface roughness of the notes. The bacterial adhesion on the notes is affected by many factors, including bacteria itself, the external environment, the surface of the notes, etc., so we have to take many factors all round to be more comprehensive and objective when study bacterial adhesion.(3)Comprehensive summary and analyze the research findings of the mechanical mechanism of bacterial adhesion. In the bacterial adhesion process, it is divided into specific adhesion and non-specific adhesion, in which van der Waals is a common adhesion force, and other forces exist in the case of certain conditions. In the adhesion process, there is static electricity, the capillary force, the force generated by the special structure of the bacteria, hydrogen bonding, chemical bonding force; Bacterial cell structure, the surface of the notes and external environmental factors can also affect bacterial adhesion.(4)Use MATLAB to visually simulate the adhesion forces, to deepen understanding and analysis of the model, and also compared. Visually display the changes of each parameter and variable, as well as the impact on adhesion. In the process of bacterial adhesion with the notes, when the distance between notes and the bacteria reduced to2×10-7m, the van der Waals force increases rapidly. When the radius of the protruding part r<2×10-9m, the roughness increases, the speed of the van der Waals force increases faster. And, through the analysis, in the nm order of magnitude, the electrostatic force is2-3orders of magnitude bigger than the van der Waals. And the capillary force is about two orders of magnitude larger than the electrostatic force.(5)To study and structure the bacterial physical model. Using ANSYS to simulate, loading load for mechanical analysis, research and analyze the stress distribution in the bacterial cells and changes. This is an exploratory study, and the effectiveness and applicability of the findings is unknown, but it has some value as an attempt, which could support and have references for deeper and extensive research.(6)Simulate and analyze the simulation of the bacteria using ANSYS, and the stress distribution and the transfer rule within the cell model are: with the applied displacement, the stress spreads along the central axis and spreads around at the same time, but it spreads to the surrounding slower. Because of the presence of external load and the flow of cytoplasm, there is pressure on the cell wall, resulting changes in stress distribution. Moreover, with the load applied, the stress distribution of perpendicular to the loading direction changed more significantly than the loading direction.(7)By previous research, comprehensive understanding the bacteria adhesion and mechanics on the notes surface, so that people can find healthy, safe way when using notes, and it also has important implications for notes of sterilization, and provides a theoretical basis for the sterilization issue of paper items (books, bags, etc.).