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Effects of Temperature on Melt Electrospinning: Experiment and Simulation Study
Xiaoqi Mu,Yuansheng Zheng,Xueqin Li,Binjie Xin,Lantian Lin 한국섬유공학회 2021 Fibers and polymers Vol.22 No.4
In this study, the jet formation progress, jet motion, resultant fiber diameter, fiber mat morphology, inner structuresand mechanical properties of the fibers prepared at different heating temperatures via melt electrospinning system werestudied, in a comprehensive and systematic manner. The temperature distribution of the melt electrospinning configurationwas simulated, in order to provide a good deal of insight into the experimental results. High-speed photography was adoptedto capture the images of jet formation process and jet motion during melt electrospinning. The experimental results showedthat higher heating temperature at the spinneret results in shorter jet formation time, smaller fiber diameter, more disorderedfiber mat, lower degree of crystallinity and strength. The simulation works was carried out, aimed at facilitating to deeplyunderstand the experimental results.
The Effects of Electric Field on Jet Behavior and Fiber Properties in Melt Electrospinning
Xueqin Li,Yuansheng Zheng,Xiaoqi Mu,Binjie Xin,Lantian Lin 한국섬유공학회 2020 Fibers and polymers Vol.21 No.5
The electric field and temperature are the two important factors that influence the diameter and properties of fiberin the melt electrospinning process. It is commonly known that the polymer jet behavior is governed by the electric fieldwithin spinning area. In present work, a comprehensively-designed and properly-conducted analysis was carried out toinvestigate into the effects of electric field on the jet behaviors, diameters, crystalline structure and mechanical properties ofthe resultant fibers. An auxiliary electrode was invited to enhance the electric field strength. The high-speed photography wasadopted to capture the jet motion, and also, the numerical simulation was used to understand the electric field distribution. Bymaking use of the whipping amplitude and whipping frequency, the characteristics of jet behavior were described. It wasfound that by applying an auxiliary electrode, the average fiber diameter reduced from 61.01 μm to 9.06 μm, and thecrystallinity and strength of the fiber was improved with the help of the higher electric filed intensity. In addition, the moreuniform electric field would produce finer and more uniform fiber because of the more stable jet motion.
Research on steady characteristics of human-robot system for preventing elderly falls during walking
Xiao Dong Zhang,Xiaoqi Mu,Liangliang Li,Ahmad Bala Alhassan,Khaled Kadry Hamza 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.9
Due to the ever-increasing demand of caregivers and the high cost of nursing the elderly, researchers have been developing the elderly assistant robots (EARs) for assisting the elderly. To improve the safety of the elderly during walking, the steady characteristics of the EAR are discussed for preventing elderly falls during walking in this paper. Initially, the walking elderly was modeled as an inverted pendulum, and the steadiness region of the human and the general elderly fall conditions were obtained. The dynamics of the human-robot system were derived for preventing the general elderly falls. Also, the steadiness of the human and the robot were analyzed, respectively. Finally, experiments were conducted to verify the effectiveness of the models. The results demonstrated that the system met the requirements of steadiness, and hence, the designed robot could prevent elderly fall during walking. Thus, this study provides a theoretical basis for the effective control and the practical application of the EARs.