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Zhou J.,Tongji University | Chen J.-F.,Tongji University | Xue J.-F.,Monash University | Wang J.-Q.,Guangxi University of Science and Technology
Geosynthetics International

To study the interaction between sand particles and geogrids, pullout tests were performed on one type of geogrid in Pingtan medium sand. The sand motion around the ribs was captured by high-resolution digital camera and CCD camera. The images were analysed with the aid of digital photography measurement and micro-image analysis. Microscopic particle motion and displacement fields around the transverse ribs were then obtained to verify the macro behaviour of the sand-rib interaction. It was found that the thickness of shear band increases with the normal stress applied, and the shear zone is asymmetrical to the soil-rib interface. A near wedge shape shear zone was observed by analysing the shear strain around the ribs, which indicated that a punching shear failure mechanism may be applicable to the tested geogrid in medium-dense sand. Comparison of various models for bearing capacity of geogrids shows that the size and shape of bearing members should be considered in the calculation of bearing resistance of geogrids. Source

Using beam and tetrahedron elements to simulate nanocrystalline cellulose (NCC), single wall carbon nanotube (SWCNT) and polypropylene (PP), finite element method (FEM) is used to predict the mechanical properties of nano-composites. The bending, shear and torsion behaviors of nano-composites are especially investigated due to the limited amount of information in the present literature. First, mixed method (MM) and FEM are used to compare the bending stiffness of NCC/PP and SWCNT/PP composites. Second, based on mechanics of materials, the shear moduli of both types of nano-composites are obtained. Finally, fixing the number of fibers and for different volume contents, four NCC lengths are used to determine the mechanical properties of the composites. The bending and shearing performances are also compared between NCC and SWCNT based composites. In all cases, the elastic-plastic analyses are carried out and the stress or strain distributions for specific regions are also investigated. From all the results obtained, an economic analysis shows that NCC is more interesting than SWCNT to reinforce PP. © 2014. Source

Jun W.,Guangxi University of Science and Technology
Chinese Journal of Tissue Engineering Research

BACKGROUND: Elderly patients may suffer from cognitive dysfunction after arthroplasty, which easily leads to the emergence of various postoperative complications, and even leads to the death of the patient. Different methods of analgesia are used to reduce the incidence of cognitive dysfunction after lower limb arthroplasty in elderly patients. OBJECTIVE: To compare the incidence of early cognitive dysfunction in elderly patients with total knee arthroplasty under different analgesia. METHODS: A total of 82 elderly patients with total knee arthroplasty in the Liuzhou City People’s Hospital Affiliated to Guangxi University of Science and Technology from December 2013 to December 2014 were enrolled in this study, equally and randomly assigned to control group and observation group, which received general anesthesia and epidural anesthesia, respectively. At 3 days after arthroplasty, Mini Mental State Examination score, visual analogue scale score and incidence rate of postoperative cognitive dysfunction in the two groups were observed and compared. RESULTS AND CONCLUSION: No significant difference in Mini Mental State Examination score was detected between the two groups (P > 0.05), but visual analogue scale score and incidence rate of postoperative cognitive dysfunction were significantly lower in the observation group than in the control group (P < 0.05). Moreover, visual analogue scale score was an independent risk factor for postoperative cognitive dysfunction (P < 0.05). These findings suggest that regarding the effect in the early postoperative cognitive function, implementation of intravenous anesthesia or epidural anesthesia in elderly patients undergoing total knee arthroplasty does not have apparent difference. As for the incidence of postoperative analgesic effect and postoperative cognitive dysfunction, epidural analgesia is better. Through analysis, the pain is a risk factor for cognitive dysfunction after total knee arthroplasty in elderly patients. © 2015, Journal of Clinical Rehabilitative Tissue Engineering Research. All rights reserved. Source

Luo G.K.,Guangxi University of Science and Technology
Journal of Software Engineering

In this study, an image segmentation using automatic selected threshold method based on improved genetic algorithm is presented. It can overcome the shortcomings of the existing image segmentation methods which only consider pixel gray value without considering spatial features and computational complexity of these algorithms is too large. Encoding, crossover, mutation operator and other parameters of genetic algorithm are improved moderately in this method. Optimal threshold for image segmentation is converted into an optimization problem in this new method. The selection algorithm is optimized by using simulated annealing temperature parameters to achieve selective pressures. In order to achieve image segmentation, the optimal threshold is solved by using optimizing efficiency of improved genetic algorithm. Simulation results show that the new algorithm greatly reduces the optimization time and enhances the anti-noise performance of image segmentation and improves the efficiency of image segmentation. Thus, the new method can facilitate subsequent processing for computer vision and can be applied to real-time image segmentation. © 2014 Academic Journals Inc. Source

Chen L.,Guangxi University of Science and Technology
Jinshu Rechuli/Heat Treatment of Metals

Effects of aging temperature, holding time and cooling speed on the potentiodynamic polarization curves of 2205 duplex stainless steel were investigated. Microstructure morphologies of the specimens under solution and different aging treatments were observed, the main factors to influence corrosion resistance of duplex stainless steel plate were analyzed. The results show that when aged at 950 ℃, a preferable corrosion resistance can be obtained, while aged at 850 ℃, it is worst. When change the cooling method after aging from air cooling to water cooling, all the uniform corrosion resistance and pitting corrosion resistance are improved. Source

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