Bolt looseness detection and localization using time reversal signal and neural network techniques

Zhifeng Tang,Yuan-Feng Duan,Xiaodong Sui,Chung Bang Yun 국제구조공학회 2022 Smart Structures and Systems, An International Jou Vol.30 No.4

It is essential to monitor the working conditions of bolt-connected joints, which are widely used in various kinds of steel structures. The looseness of bolts may directly affect the stability and safety of the entire structure. In this study, a guided wave-based method for bolt looseness detection and localization is presented for a joint structure with multiple bolts. SH waves generated and received by a small number (two pairs) of magnetostrictive transducers were used. The bolt looseness index was proposed based on the changes in the reconstructed responses excited by the time reversal signals of the measured unit impulse responses. The damage locations and local damage severities were estimated using the damage indices from several wave propagation paths. The back propagation neural network (BPNN) technique was employed to identify the local damages. Numerical and experimental studies were conducted on a lap joint with eight bolts. The results show that the total damage severity can be successfully detected under the effect of external force and measurement noise. The local damage severity can be estimated reasonably for the experimental data using the BPNN constructed by the training patterns generated from the finite element simulations.

Preparation of decorative slag glass-ceramics and research on the solidification of heavy metals

Yang Tang,Xiaodong Hao,Zhenxiang Fang,Xinyu Bai,Guangyu Wang,Hongxia Zhang,Leibo Deng,Hua Chen,Ming Zhao,Yongsheng Du 한양대학교 청정에너지연구소 2023 Journal of Ceramic Processing Research Vol.24 No.1

Glass-ceramics with different CuO additions were prepared with Fe2O3 and Cr2O3 as composite nucleating agents, rare earthcontainingblast furnace slag (REBFS) as the main raw material. The existence state and stability of heavy metals Cu, Mn andCr in glass-ceramics were investigated. The results showed that Cr ions contributed to the generation of spinel phase, whileCu ions and Mn ions can enter the spinel crystal and exist stably, which indicated that there was a synergistic solidificationof Cu, Mn and Cr. The depolymerization effect of the copper ions contributed to the transformation of the crystal morphologyfrom dendrites to spherulites. Moreover, the increase in CuO contents promoted glass-ceramics from green to copper red. Based on the leaching experimental data analysis of heavy metals in glass-ceramics, the leaching concentration of heavy metalsCu, Cr and Mn were much lower than the standard leaching toxicity limit of hazardous waste (GB5085.3–2007, China). Theresults showed that the conversion of REBFS into environmentally friendly glass-ceramics can realize solid waste resourceutilization.

Fructus mume Protects Against Cigarette Smoke Induced Chronic Cough Guinea Pig

Juan Xiang,Xiaodong Liu,Shan Zhong,Zhangfu Fang,Shuirong Shen,Jiaman Tang,Siqi Lai,Kefang Lai 한국식품영양과학회 2020 Journal of medicinal food Vol.23 No.2

Fructus mume was recorded in the Chinese Pharmacopoeia and traditional Chinese medical books for chronic cough, but the effect and related constituents are still unknown. Thus, we investigated the protect effects and the relevant constituents of F. mume in a guinea pig model with chronic cough induced by cigarette smoke (CS). The organic acids and polysaccharides in F. mume were detected by high performance liquid chromatography, gel permeation chromatography, and gas chromatography–mass spectrometry. The guinea pigs were orally administered with vehicle or the water extract of Fructus mume (FW) during the 14 days of CS exposure. Citric acid induced coughs were automatically measured by Buxco system. The differential cells in bronchoalveolar lavage fluid (BALF) and histopathological changes in lung tissue were assessed by hematoxylin and eosin staining. The tumor necrosis factor alpha (TNF-α) and interleukin-8 (IL-8) levels in lung tissue were detected via enzyme-linked immunosorbent assay. The mucus productions in tracheas were determined with Alcian blue-periodic acid Schiff staining. The results suggested relatively high concentration of citric acid, chlorogenic acid, and neochlorogenic acid in F. mume, and high proportion of galactose and glucose and lower molecular weight of polysaccharides. Administration of FW significantly reduced the cough frequency, decreased inflammatory cells in BALF and lung tissue, and attenuated the thickening of airway epithelium and submucosa compared with CS-exposure group. Moreover, the overproduction of TNF-α and IL-8 in lung tissues, and mucus in central airways of CS-induced guinea pigs was markedly inhibited by FW. The extract could also protect against CS exposure-induced chronic cough in guinea pigs by reducing coughs, airway inflammation, and mucus overproduction.

STAT3, a Poor Survival Predicator, Is Associated with Lymph Node Metastasis from Breast Cancer

Yujuan Chen,Xiaodong Wang,Xuejuan Liu,Hongjiang Li,Qing Lv,Jingqiang Zhu,Bing Wei,Ying Tang,JING WANG 한국유방암학회 2013 Journal of breast cancer Vol.16 No.1

Purpose: The aim of this study is to explore signal transducer and activator of transcription 3 (STAT3) expression in breast cancer and to analyze the detailed mechanism that STAT3 contributes to the progression of breast cancer. Methods: We retrospectively analyzed the clinicopathologic characteristics and overall survival (OS) of 140 breast cancer patients after curative surgery, and detected STAT3 expression, phosphorylated STAT3 (pSTAT3) expression, Ki-67 expression, vascular endothelial growth factor (VEGF)-C and -D expression in breast cancer tissues, and adjacent nontumor tissues. Survival analysis and relationship analysis were adopted for demonstrated the important mechanism of STAT3 contribution to progression of breast cancer. Results: STAT3 expression, pSTAT3 expression, Ki-67 expression, VEGF-C expression, and VEGF-D expression in breast cancer tissues were significantly higher than those in adjacent nontumor tissues, respectively. With survival analysis, only number of lymph node metastasis (N stage) was identified as the independent predictors of the OS of breast cancer patients. Besides, we demonstrated there was the most prominent correlation between STAT3 expression and lymph node metastasis in breast cancer tissues by using the multinominal regression method. Conclusion: STAT3, a poor survival biomarker potential association with lymph node metastasis, was suitable for predication the OS of breast cancer patients after curative resection.

Effect of Fe nanoparticle-loaded sawdust carbon on catalytic pyrolysis of heavy oil

Yitang Zhong,Xiaodong Tang,Jingjing Li,Bin He,Zhiqi Zhang,Tingbing Chen 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.4

This work was focused on the synthesis and characterization of iron nanoparticle loaded sawdust carbon(Fe/SC) by low cost green synthesis approach and its application for catalytic pyrolysis of heavy oil. Fourier transforminfrared (FT-IR), X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS),transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS) and inductively coupled plasmaoptical emission spectrometer (ICP-OES) methods were used to analyze the catalyst of Fe/SC. The properties of heavyoil before and after reaction were characterized by SARA analysis, FT-IR, gas chromatography-mass spectrometry (GCMS)and thermogravimetric analysis (TGA). The experimental results showed that after pyrolytic reaction at 350 oC for30 min with 0.1 wt% catalyst, the viscosity of heavy oil may decrease by 80.81% with a net efficiency of catalyst of20.68%. The catalyst of Fe/SC is promising, low cost, high efficiency, highly stable and eco-friendly for catalytic upgradingand viscosity reduction of heavy oil.

Clustering Strategy Based on Graph Method and Power Control for Frequency Resource Management in Femtocell and Macrocell Overlaid System

Hongjia Li,Xiaodong Xu,Dan Hu,Xiaofeng Tao,Ping Zhang,Song Ci,Hui Tang 한국통신학회 2011 Journal of communications and networks Vol.13 No.6

In order to control interference and improve spectrumef-ficiency in the femtocell and macrocell overlaid system (FMOS), we propose a joint frequency bandwidth dynamic division, clustering and power control algorithm (JFCPA) for orthogonal-frequencydivision-multiple access-based downlink FMOS. The overall system bandwidth is divided into three bands, and the macro-cellular coverage is divided into two areas according to the intensity of the interference from the macro base station to the femtocells, which are dynamically determined by using the JFCPA. A cluster is taken as the unit for frequency reuse among femtocells. We map the problem of clustering to the MAX k-CUT problem with the aim of eliminating the inter-femtocell collision interference, which is solved by a graph-based heuristic algorithm. Frequency bandwidth sharing or splitting between the femtocell tier and the macrocell tier is determined by a step-migration-algorithm-based power control. Simulations conducted to demonstrate the effectiveness of our proposed algorithm showed the frequency-reuse probability of the FMOS reuse band above 97.6% and at least 70% of the frequency bandwidth available for the macrocell tier, which means that the co-tier and the cross-tier interference were effectively controlled. Thus, high spectrum efficiency was achieved. The simulation results also clarified that the planning of frequency resource allocation in FMOS should take into account both the spatial density of femtocells and the interference suffered by them. Statistical results from our simulations also provide guidelines for actual FMOS planning.

Discrete Track Recording Media for High Capacity Hard Disk Drive

Hyung J Lee,Xiaodong Che,Ki-Seok Moon,Yawshing Tang,Nayoung Kim,Matthew Moneck,Jian-Gang Zhu,Nobuyuki Takahashi 한국자기학회 2007 한국자기학회 학술연구발표회 논문개요집 Vol.- No.-

Clustering Strategy Based on Graph Method and Power Control for Frequency Resource Management in Femtocell and Macrocell Overlaid System

Li, Hongjia,Xu, Xiaodong,Hu, Dan,Tao, Xiaofeng,Zhang, Ping,Ci, Song,Tang, Hui The Korea Institute of Information and Commucation 2011 Journal of communications and networks Vol.13 No.6

In order to control interference and improve spectrum efficiency in the femtocell and macrocell overlaid system (FMOS), we propose a joint frequency bandwidth dynamic division, clustering and power control algorithm (JFCPA) for orthogonal-frequency-division-multiple access-based downlink FMOS. The overall system bandwidth is divided into three bands, and the macro-cellular coverage is divided into two areas according to the intensity of the interference from the macro base station to the femtocells, which are dynamically determined by using the JFCPA. A cluster is taken as the unit for frequency reuse among femtocells. We map the problem of clustering to the MAX k-CUT problem with the aim of eliminating the inter-femtocell collision interference, which is solved by a graph-based heuristic algorithm. Frequency bandwidth sharing or splitting between the femtocell tier and the macrocell tier is determined by a step-migration-algorithm-based power control. Simulations conducted to demonstrate the effectiveness of our proposed algorithm showed the frequency-reuse probability of the FMOS reuse band above 97.6% and at least 70% of the frequency bandwidth available for the macrocell tier, which means that the co-tier and the cross-tier interference were effectively controlled. Thus, high spectrum efficiency was achieved. The simulation results also clarified that the planning of frequency resource allocation in FMOS should take into account both the spatial density of femtocells and the interference suffered by them. Statistical results from our simulations also provide guidelines for actual FMOS planning.

Investigation into the Effectiveness of Ultrasonic Tomography for Grouting Quality Evaluation

Jiangbo Lu,Shenghua Tang,Xiaodong Dai,Zhi Fang 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.12

This study is aimed to determine the influence of the parameters relevant for the application of ultrasonic tomography in the field of grouting quality evaluation. The parameters tested were the wave velocity difference between concrete and grout (VDCG), the type of material used for a pipe, and the type of pre-stressed tendon within the pipe. Fourteen cube specimens were constructed, and a theoretical model was used to analyse the effects of these parameters. The results show that these parameters affect each other on the detection effectiveness of ultrasonic tomography, and that VDCG affects it most. It was found that ultrasonic tomography is suitable for the evaluation of grouting quality in post-tensioned structures when VDCG is small and the type of tendon used is a steel bar.

Diameter-Selective Synthesis of Single-Walled Carbon Nanotubes on Supported Cobalt Catalysts

Hong Wang,Lian Yang,Pingting Chen,Xiaodong Tang,Jin Yang,Sha Zhu,Yuanyi Liao 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.8

Supported Co catalysts were prepared by impregnating the support (MgO, SiO2 and Al2O3) with Co(acac)2 solution, and diameter-selective growth of single-walled carbon nanotubes (SWCNTs) by ethanol chemical vapor deposition has been assessed on these Co catalysts. In contrast to Co/SiO2 and Co/Al2O3 catalysts with relatively high surface areas, Co/MgO catalyst with a low surface area demonstrates the best performances in the diameter-selective growth of SWCNTs under an optimal growth condition. Multiple characterizations on catalysts and SWCNTs revealed that Co(acac)2 was absorbed on MgO by ligand exchange and anhydrous solvent CH2Cl2 strengthened the anchoring of Co(acac)2 on the MgO surface, which resulted in well-dispersed Co species upon calcination in air. Under a modest reduction temperature, the reduction of Co oxides provided Co clusters, which were anchored by the unreacted Co ions in the interior of MgO support, leading to the synthesis of SWCNTs with a narrow diameter distribution.