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Electrospun non-leaching biocombatible antimicrobial cellulose acetate nanofibrous mats
Rong Li,Xuehong Ren,Qianyuan Jiang,Zhiwei Xie,Tung-Shi Huang 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.27 No.-
In this study cellulose acetate (CA) was modified with 4,40-diphenylmethane diisocyanate (MDI, an Nhalamineprecursor) in solution to form chemical bonds between CA and MDI to avoid the potentialrelease of biocides from CA. Nanofibers were obtained by electrospinning the CA–MDI solution. Theobtained CA–MDI nanofibers were characterized by FT-IR, SEM, TGA and DSC. TGA and DSC dataindicated that the CA–MDI nanofibers before and after chlorination had good thermal stability comparedwith CA nanofibers. 58% of active chlorine was lost after 2 h of UVA irradiation, and most of the activechlorine was lost after 4 h of UVA irradiation. However, about 85% of the chlorine could be regeneratedby rechlorination after 24 h of UVA irradiation. The active chlorine of the chlorinated nanofibers releasedslowly in water. The chlorinated CA–MDI nanofibers showed excellent antimicrobial properties againstEscherichia coli O157:H7 and Staphylococcus aureus within brief contact times. Also, the chlorinated CA–MDI nanofibers showed good biocompatibility.
Design and evaluation of spur gear pairs with improved bearing capacity and lubrication performance
Lei Liu,Zhiwei Chen,Rong Kong 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.3
The tooth form is the most influential factor on the bearing capacity and operation performance of a gear drive. Tooth profiles of spur gears can be designed based on control of relative curvature of conjugate profiles, but how to conceive appropriate control strategies and appraise gear pairs accurately needs to be investigated in depth. This paper presents the control strategies through analysis of the effect mechanisms of relative curvature on the bearing capacity and lubrication performance. Evaluation approaches of the gear pairs are then proposed by establishing the analytical models (AMs). In case studies, gear pairs with optimal comprehensive performance are designed through five control strategies. The AMs for contact and bending capacity are validated with the finite element models. The effects of the control strategies are discussed through comparative analysis. Results reveal that the control strategies lead to remarkable enhancement of bearing capacity and lubrication performance.