Topology Optimization for Large-displacement Compliant Mechanisms Using Element Free Galerkin Method

Du, Yixian,Chen, Liping Society for Computational Design and Engineering 2008 International Journal of CAD/CAM Vol.8 No.1

This paper presents a topology optimization approach using element-free Galerkin method (EFGM) for the optimal design of compliant mechanisms with geometrically non-linearity. Meshless method has an advantage over the finite element method(FEM) because it is more capable of handling large deformation resulted from geometrical nonlinearity. Therefore, in this paper, EFGM is employed to discretize the governing equations and the bulk density field. The sensitivity analysis of the optimization problem is performed by incorporating the adjoint approach with the meshless method. The Lagrange multipliers method adjusted for imposition of both the concentrated and continuous essential boundary conditions in the EFGM is proposed in details. The optimization mathematical formulation is developed to convert the multi-criteria problem to an equivalent single-objective problem. The popularly applied interpolation scheme, solid isotropic material with penalization (SIMP), is used to indicate the dependence of material property upon on pseudo densities discretized to the integration points. A well studied numerical example has been applied to demonstrate the proposed approach works very well and the non-linear EFGM can obtain the better topologies than the linear EFGM to design large-displacement compliant mechanisms.

Evaluation of Dry Matter Intake and Average Daily Gain Predicted by the Cornell Net Carbohydrate and Protein System in Crossbred Growing Bulls Kept in a Traditionally Confined Feeding System in China

Du, Jinping,Liang, Yi,Xin, Hangshu,Xue, Feng,Zhao, Jinshi,Ren, Liping,Meng, Qingxiang Asian Australasian Association of Animal Productio 2010 Animal Bioscience Vol.23 No.11

Two separate animal trials were conducted to evaluate the coincidence of dry matter intake (DMI) and average daily gain (ADG) predicted by the Cornell Net Carbohydrate and Protein System (CNCPS) and observed actually in crossbred growing bulls kept in a traditionally confined feeding system in China. In Trial 1, 45 growing Simmental${\times}$Mongolia crossbred F1 bulls were assigned to three treatments (T1-3) with 15 animals in each treatment. Trial 2 was conducted with 60 Limousin${\times}$Fuzhou crossbred F2 bulls allocated to 4 treatments (t1-4). All of the animals were confined in individual stalls. DMI and ADG for each bull were measured as a mean of each treatment. All of the data about animals, environment, management and feeds required by the CNCPS model were collected, and model predictions were generated for animals on each treatment. Subsequently, model-predicted DMI and ADG were compared with the actually recorded results. In the three treatments in Trial 1, 93.3, 80.0 and 73.3% of points fell within the range from -0.4 to 0.4 kg/d for DMI mean bias; similarly, in the four treatments in Trial 2, about 86.7, 73.3, 73.3 and 80.0% of points fell within the same range. These results indicate that the CNCPS model can accurately predict DMI of crossbred bulls in the traditionally confined feeding system in China. There were no significant differences between predicted and observed ADG for T1 (p = 0.06) and T2 (p = 0.09) in Trial 1, and for t1 (p = 0.07), t2 (p = 0.14) and t4 (p = 0.83) in Trial 2. However, significant differences between predicted and observed ADG values were observed for T3 in Trial 1 (p<0.01) and for t3 in Trial 2 (p = 0.04). By regression analysis, a statistically different value of intercept from zero for the regression equation of DMI (p<0.01) or an identical value of ADG (p = 0.06) were obtained, whereas the slopes were significantly different (p<0.01) from unity for both DMI and ADG. Additionally, small root mean square error (RMSE) values were obtained for the unbiased estimator of the two variances (DMI and ADG). Thus, the present results indicated that the CNCPS model can give acceptable estimates of DMI and ADG of crossbred growing bulls kept in a traditionally confined feeding system in China.

Magnetic Field Analysis and Iron Loss Calculation of a Special Switched Reluctance Generator

Zheng Li,Xin Wang,Liping Zhang,Lei Du,Qunjing Wang 대한전기학회 2019 Journal of Electrical Engineering & Technology Vol.14 No.5

In order to improve the efficiency and flexibility of the switched reluctance generator, a novel deflection double stator switched reluctance generator was proposed based on the structural characteristics of the switched reluctance motor. The magnetic flux of the generator was analyzed by magnetic circuit analysis method, obtaining the matrix expression of the average magnetic flux of the stator and rotor. Then it is transiently simulated by electromagnetic analysis software to calculate the radial and tangential components of the core magnetic density of the generator. At the same time, the calculation results of the finite element method are compared with the results of the analysis method to verify the correctness of the analytical method model. Finally, the calculated magnetic density component is transformed by Fourier transformation to obtain the corresponding harmonic analysis. And the ellipse method was used to calculate the iron loss of the generator, compared with the experimental results to illuminate the accuracy of the iron loss calculation scheme.

Task Offloading Based on Edge Collaboration in MEC-Enabled IoV Networks

Deng, Tao Yu,Chen, Yueyun,Chen, Guang,Yang, Meijie,Du, Liping 한국통신학회 2023 Journal of communications and networks Vol.25 No.2

Benefiting from its abundant computing resourcesand low computing latency, mobile edge computing (MEC) isa promising approach for enhancing the computing capacity ofthe 5G Internet of vehicles (IoV). Because of the high mobility,handover is frequent and inevitable in IoV networks. In thispaper, we investigate an edge collaborative task offloading andsplitting strategy in MEC-enabled IoV networks, in which thetask is splitted on the edge and paralleling executed by eachpart of the task on several MEC servers when handover isoccured. Applications in IoV networks have flexible requirementson latency and energy consumption. To realize the tradeoffbetween latency and energy consumption, we formulate the taskoffloading and splitting as an optimization problem with the aimof minimizing the total cost of latency and energy consumptionby jointly optimizing the task splitting ratio and uplink transmitpower of vehicle terminal (VT). Because the proposed problemis non-smooth and non-convex, we divide the original probleminto two convex subproblems, and apply an alternate convexsearch (ACS) algorithm to obtain the optimized solution withlow computational complexity. Numerical simulation results showthat the proposed method can adjust the offloading strategyproperly according to task preference, and obtain a lower totalcost compared with the baseline algorithms.

Fe-curcumin Nanozyme-Mediated Immunosuppression and Anti-inflammation in Experimental Autoimmune Uveitis

Zhengxuan Jiang,Kun Liang,Xiang Gao,Fan Cao,Guangqi An,Siyu Gui,Weiwei Tang,Liping Du,Liming Tao,Xianwen Wang 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00

Background EAU is an inflammatory disease usually characterized by autoinflammation and autoimmunity and is aggravated by excessive generation of ROS. Conventional hormone therapy often has more adverse effects. It is urgent to find a therapeutic drug with higher efficiency and fewer adverse effects. Methods We developed an Fe-curcumin nanozyme in which natural antioxidants coordinate with Fe3+ to form nanoparticles with excellent solubility for directing anti-inflammatory and ROS scavenging effects to treat EAU. Several experiments were used to detect the characteristics of nanozymes. EAU model rats were used to detect the abilities of decreasing autoinflammation and autoimmunity. PBMCs were used to detect the ability to inhibit cell proliferation. Results Free radical scavenging experiments showed that nanozymes decreased the level of free radicals at low concentrations. In vitro and in vivo experiments revealed that the group treated with Fe-curcumin nanozymes had lower inflammatory reactions and ROS levels than the control group, as reflected by the downregulated levels of several critical inflammatory cytokines, such as IFN-γ, IL-17, and TNF-α; decreased H2O2 release; inhibited proliferation of Th1 and Th17 cells; and alleviated pathological changes in the eye. Importantly, the Fe-curcumin nanozyme was detected in the retina using Prussian blue staining. Additionally, Fe-curcumin nanozyme is noncytotoxic when directing these biological activities. Conclusion This study has demonstrated the feasibility of using the Fe-curcumin nanozyme as a nanodrug to inhibit inflammatory reactions and scavenge ROS in the treatment of EAU, indicating that it may serve as a promising therapeutic agent in clinical treatment.

Dissecting the meteorological and genetic factors affecting rice grain quality in Northeast China

Chen Mojun,Li Zhao,Huang Jie,Yan Yongfeng,Wu Tao,Bian Mingdi,Zhou Jinsong,Wang Yongjun,Lyv Yanjie,Hu Guanghui,Jin Yong-Mei,Huang Kai,Guo Liping,Jiang Wenzhu,Du Xinglin 한국유전학회 2021 Genes & Genomics Vol.43 No.8

Background The Northeast Plain of China, which is an important region for the production of high grain quality rice in China. However, the grain quality of the rice produced varies across this region, even for the same cultivar. Objective In order to explore the meteorological factors that have the greatest infuence on quality and the transcriptional level diferences between diferent cultivars and diferent locations at grain flling stage. Methods We grew eight rice cultivars in three locations in Northeast China during two growing seasons (2017 and 2018). We recorded meteorological conditions, including air temperature, air temperature range, and photosynthetically active radiation (PAR) during the grain-flling stage of each cultivar, and analyzed the grain quality of those eight cultivars. Results Across all eight cultivars, meteorological factors had a stronger efect on eating quality than genotype, while genotype had a stronger efect on milling quality. Of the three environmental factors assessed, PAR was signifcantly correlated with the most grain quality traits. Using RNA-sequencing analysis, we identifed 573 environment-specifc DEGs (Diferentially Expressed Genes), and 119 genotype-specifc DEGs; 11 DEGs were responsive to genotype×environment interactions. These DEGs were involved in many key metabolic processes. Conclusion Our results indicated that interactions among environmental factors, especially PAR, afected rice quality in Northeast China. Further analyses of the DEGs identifed herein may provide useful information for future breeding programs aiming to develop high grain quality rice varieties suitable for cultivation across Northeast China.