LES of wind environments in urban residential areas based on an inflow turbulence generating approach

Shen, Lian,Han, Yan,Cai, C.S.,Dong, Guochao,Zhang, Jianren,Hu, Peng Techno-Press 2017 Wind and Structures, An International Journal (WAS Vol.24 No.1

Wind environment in urban residential areas is an important index to consider when evaluating the living environment. However, due to the complexity of the flow field in residential areas, it is difficult to specify the correct inflow boundary conditions in the large eddy simulation (LES). In this paper, the weighted amplitude wave superposition (WAWS) is adopted to simulate the fluctuating velocity data, which satisfies the desired target wind field. The fluctuating velocity data are given to the inlet boundary of the LES by developing an UDF script, which is implemented into the FLUENT. Then, two numerical models - the empty numerical wind tunnel model and the numerical wind tunnel model with spires and roughness elements are established based on the wind tunnel experiment to verify the present method. Finally, the turbulence generation approach presented in this paper is used to carry out a numerical simulation on the wind environment in an urban residential area in Lisbon. The computational results are compared with the wind tunnel experimental data, showing that the numerical results in the LES have a good agreement with the experimental results, and the simulated flow field with the inlet fluctuations can generate a reasonable turbulent wind field. It also shows that strong wind velocities and turbulent kinetic energy occur at the passageways, which may affect the comfort of people in the residential neighborhood, and the small wind velocities and vortexes appear at the leeward corners of buildings, which may affect the spreading of the pollutants.

LES of wind environments in urban residential areas based on an inflow turbulence generating approach

Lian Shen,Yan Han,C.S. Cai,Guochao Dong,Jianren Zhang,Peng Hu 한국풍공학회 2017 Wind and Structures, An International Journal (WAS Vol.24 No.1

Wind environment in urban residential areas is an important index to consider when evaluating the living environment. However, due to the complexity of the flow field in residential areas, it is difficult to specify the correct inflow boundary conditions in the large eddy simulation (LES). In this paper, the weighted amplitude wave superposition (WAWS) is adopted to simulate the fluctuating velocity data, which satisfies the desired target wind field. The fluctuating velocity data are given to the inlet boundary of the LES by developing an UDF script, which is implemented into the FLUENT. Then, two numerical models - the empty numerical wind tunnel model and the numerical wind tunnel model with spires and roughness elements are established based on the wind tunnel experiment to verify the present method. Finally, the turbulence generation approach presented in this paper is used to carry out a numerical simulation on the wind environment in an urban residential area in Lisbon. The computational results are compared with the wind tunnel experimental data, showing that the numerical results in the LES have a good agreement with the experimental results, and the simulated flow field with the inlet fluctuations can generate a reasonable turbulent wind field. It also shows that strong wind velocities and turbulent kinetic energy occur at the passageways, which may affect the comfort of people in the residential neighborhood, and the small wind velocities and vortexes appear at the leeward corners of buildings, which may affect the spreading of the pollutants.

Activating SIRT3 in peritoneal mesothelial cells alleviates postsurgical peritoneal adhesion formation by decreasing oxidative stress and inhibiting the NLRP3 inflammasome

Shen Tianli,Wu Yunhua,Wang Xingjie,Wang Zijun,Li Enmeng,Zhou Cancan,Yue Chenyang,Jiang Zhengdong,Wei Guangbing,Lian Jie,Xu Qinhong,Li Xuqi 생화학분자생물학회 2022 Experimental and molecular medicine Vol.54 No.-

Peritoneal adhesions (PAs) are a serious complication of abdominal surgery and negatively affect the quality of life of millions of people worldwide. However, a clear molecular mechanism and a standard therapeutic strategy for PAs have not been established. Here, we developed a standardized method to mimic the pathological changes in PAs and found that sirtuin 3 (SIRT3) expression was severely decreased in adhesion tissues, which was consistent with our bioinformatics analysis and patient adhesion tissue analysis. Thus, we hypothesized that activating SIRT3 could alleviate postsurgical PAs. Sirt3-deficient (Sirt3−/−) mice exhibited many more PAs after standardized abdominal surgery. Furthermore, compared with wild-type (Sirt3+/+) mice, Sirt3-deficient (Sirt3−/−) mice showed more prominent reactive oxygen species (ROS) accumulation, increased levels of inflammatory factors, and exacerbated mitochondrial damage and fragmentation. In addition, we observed NLRP3 inflammasome activation in the adhesion tissues of Sirt3−/− but, not Sirt3+/+ mice. Furthermore, mesothelial cells sorted from Sirt3−/− mice exhibited impaired mitochondrial bioenergetics and redox homeostasis. Honokiol (HKL), a natural compound found in several species of the genus Magnolia, could activate SIRT3 in vitro. Then, we demonstrated that treatment with HKL could reduce oxidative stress and the levels of inflammatory factors and suppress NLRP3 activation in vivo, reducing the occurrence of postsurgical PAs. In vitro treatment with HKL also restored mitochondrial bioenergetics and promoted mesothelial cell viability under oxidative stress conditions. Taken together, our findings show that the rescue of SIRT3 by HKL may be a new therapeutic strategy to alleviate and block postsurgical PA formation.

Analysis on Robust Passivity of Uncertain Neural Networks with Time-Varying Delays via Free-Matrix-Based Integral Inequality

Shen-Ping Xiao,Hong-Hai Lian,Hong-Bing Zeng,Gang Chen,Wei-Hua Zheng 제어·로봇·시스템학회 2017 International Journal of Control, Automation, and Vol.15 No.5

This paper investigates the robust delay-dependent passivity problem of neural networks (NNs) with time-varying delays and parameter uncertainties. A suitable augmented Lyapunov-Krasovskii functional (LKF) with triple integral term, which takes full use of the neuron activation function conditions and the information of time-delay in integral term, is constructed. Furthermore, by utilizing integral inequality proposed recently and the combining reciprocally convex method to estimate the derivative of the LKF, some less conservative robust passivity conditions are derived in terms of LMI. The superiority of presented approaches are demonstrated via two classic numerical examples.

Seismic Story Shear Distribution Based on Inelastic State of Eccentrically Braced Frame with Vertical Link Composite High Strength Steel

Ming Lian,Shen Li,Xiaolei Li 한국강구조학회 2021 International Journal of Steel Structures Vol.21 No.4

The story shear distribution based on inelastic state of eccentrically braced frames with vertical link fabricated with high strength steel (Y-HSS-EBFs) are proposed in this paper, four groups of Y-HSS-EBF prototypes with diff erent stories are established in SAP2000 software. Moreover, the eff ects of structural height, velocity pulse of near-fault ground motions and acceleration cumulative eff ect of far-fault ground motions are considered. Nonlinear dynamic analyses are conducted to research the seismic story shear distribution of the structures under severe earthquakes. The story shear force distribution in inelastic state of Y-HSS-EBF is proposed based on equivalent base shear method provided in current design code, and the non-linear dynamic results are compared to lateral force distribution and other story shear distributions. The results indicated that near-fault earthquakes with velocity pulse and far-fault earthquakes with acceleration cumulative present diff erent eff ect on the seismic story shear distribution of structures, the story shear distribution of Y-HSS-EBFs proposed in this paper is very practical and it can be a reference for the performance-based seismic design method for Y-HSS-EBFs.

Observer-based Distributed Coordinated Tracking Control for Multiple Simple-pendulum Network Systems with Time-varying Delays

Yu-lian Jiang,Yuanchun Li,Shen-quan Wang 제어·로봇·시스템학회 2017 International Journal of Control, Automation, and Vol.15 No.6

For networked control systems consisting of multiple simple-pendulums driven by corresponding DCmotors with time-varying communication and input delays, a distributed coordinated controller via observer-basedoutput feedback is designed to solve the tracking problem under both fixed and jointly-connected switching topologies. Firstly, the linearized dynamic model for multiple nonlinear simple-pendulum network systems with DCmotors is presented, and the distributed coordinated tracking problem considering time-varying input delays ismathematically described. Then the distributed observer-based tracking control protocol with time-varying communicationand input delays is proposed, and simultaneously, both the observer gain and feedback gain are designed. Two examples are simulated to demonstrate consensus tracking for three types of states, i.e., swing angles, angularvelocities of multiple simple-pendulums and armature currents of DC motors can be completed utilizing thedeveloped coordinated tracking control with fixed and jointly connected topologies.

A general construction method of the forcing term for discrete unified gas kinetic scheme in the thermal and compressible cases

Jie Shen,Zhiming Lu,Lian-Ping Wang 한국전산유체공학회 2022 한국전산유체공학회 학술대회논문집 Vol.2022 No.10

Current progress on gold recovery from refractory ore and waste electrical and electronic equipment

Ji Xuran,Shen Zhijie,Xu Wenping,Yao Shimiao,Zhang Hairong,Xiong Lian,Li Hailong,Guo Haijun,Chen Xuefang,Chen Xinde 한국화학공학회 2023 Korean Journal of Chemical Engineering Vol.40 No.9

The physical and chemical properties of gold promote its application, such as in the high-tech, electronic products, and aerospace industries. The easily leachable ore is gradually depleted. Thus, it becomes necessary to extract gold from other resources such as refractory ore and electrical and electronic equipment. The normal method of leaching for gold is cyanide leaching, but it is very dangerous for both environment and operator. Non-cyanide leaching methods, including thiourea leaching, halide leaching, and sulfate leaching have been developed to substitute cyanide leaching. A variety of methods to enrich gold from leaching solutions are described in this paper, including solvent extraction, electrowinning, activated carbon adsorption, and ion exchange resins. Among those methods, ion exchange resins can adsorb gold with high adsorption efficiency and regenerate easily as well. This paper focuses on the research progress of the recovery of gold from non-cyanide leachates by ion exchange resins, summarizes the existing resin types and elution processes, points out the limitations in the application of current ion exchange resins, and discusses possible solutions.

Mite and Booklouse Fauna From Vacuumed Dust Samples From Beijing

Jin-Lu Sun,Lian Shen,Jun Chen,Jin-Miao Yu,Jia Yin 대한천식알레르기학회 2014 Allergy, Asthma & Immunology Research Vol.6 No.3

A significant-source of allergens come from house dust that contain particles derived from arthropods, molds, and pet dander. This study evaluatedmite and booklouse fauna from vacuumed dust samples in Beijing China (a temperate zone). Our survey was carried out in Beijing in the homes ofmite allergic patients who visited our Allergy Department. In total, 38 homes were selected for the collection of dust samples by vacuuming, fromDecember 2008 to January 2010. The flotation method was used to isolate mites from house dust. Permanent slides were prepared for mite specimensand mites were identified and counted under a microscope. In total, 1,798 separate mite and insect specimens were found in 345 dust samplestaken from 38 homes. A total of 95 individual Dermatophagoides (D) siboney were detected in 35 dust samples from 19 homes (representing5.3% of all mite and insect species found in house dust); in addition, this mite was found to co-exist with D. farinae (Hughes, 1961) in 33 dust samples. Our results demonstrated the presence D. siboney that co-existed with D. farinae in house dust in Beijing China (a temperate zone).

Accurate Segmentation of CT Male Pelvic Organs via Regression-Based Deformable Models and Multi-Task Random Forests

Gao, Yaozong,Shao, Yeqin,Lian, Jun,Wang, Andrew Z.,Chen, Ronald C.,Shen, Dinggang IEEE 2016 IEEE transactions on medical imaging Vol.35 No.6

<P>Segmenting male pelvic organs from CT images is a prerequisite for prostate cancer radiotherapy. The efficacy of radiation treatment highly depends on segmentation accuracy. However, accurate segmentation of male pelvic organs is challenging due to low tissue contrast of CT images, as well as large variations of shape and appearance of the pelvic organs. Among existing segmentation methods, deformable models are the most popular, as shape prior can be easily incorporated to regularize the segmentation. Nonetheless, the sensitivity to initialization often limits their performance, especially for segmenting organs with large shape variations. In this paper, we propose a novel approach to guide deformable models, thus making them robust against arbitrary initializations. Specifically, we learn a displacement regressor, which predicts 3D displacement from any image voxel to the target organ boundary based on the local patch appearance. This regressor provides a non-local external force for each vertex of deformable model, thus overcoming the initialization problem suffered by the traditional deformable models. To learn a reliable displacement regressor, two strategies are particularly proposed. 1) A multi-task random forest is proposed to learn the displacement regressor jointly with the organ classifier; 2) an auto-context model is used to iteratively enforce structural information during voxel-wise prediction. Extensive experiments on 313 planning CT scans of 313 patients show that our method achieves better results than alternative classification or regression based methods, and also several other existing methods in CT pelvic organ segmentation.</P>