Structural health monitoring of a newly built high-piled wharf in a harbor with fiber Bragg grating sensor technology: design and deployment

Liu, Hong-biao,Zhang, Qiang,Zhang, Bao-hua Techno-Press 2017 Smart Structures and Systems, An International Jou Vol.20 No.2

Structural health monitoring (SHM) of civil infrastructure using fiber Bragg grating sensor networks (FBGSNs) has received significant public attention in recent years. However, there is currently little research on the health-monitoring technology of high-piled wharfs in coastal ports using the fiber Bragg grating (FBG) sensor technique. The benefits of FBG sensors are their small size, light weight, lack of conductivity, resistance corrosion, multiplexing ability and immunity to electromagnetic interference. Based on the properties of high-piled wharfs in coastal ports and servicing seawater environment and the benefits of FBG sensors, the SHM system for a high-piled wharf in the Tianjin Port of China is devised and deployed partly using the FBG sensor technique. In addition, the health-monitoring parameters are proposed. The system can monitor the structural mechanical properties and durability, which provides a state-of-the-art mean to monitor the health conditions of the wharf and display the monitored data with the BIM technique. In total, 289 FBG stain sensors, 87 FBG temperature sensors, 20 FBG obliquity sensors, 16 FBG pressure sensors, 8 FBG acceleration sensors and 4 anode ladders are installed in the components of the back platform and front platform. After the installation of some components in the wharf construction site, the good signal that each sensor measures demonstrates the suitability of the sensor setup methods, and it is proper for the full-scale, continuous, autonomous SHM deployment for the high-piled wharf in the costal port. The South 27# Wharf SHM system constitutes the largest deployment of FBG sensors for wharf structures in costal ports to date. This deployment demonstrates the strong potential of FBGSNs to monitor the health of large-scale coastal wharf structures. This study can provide a reference to the long-term health-monitoring system deployment for high-piled wharf structures in coastal ports.

Seismic response of steel reinforced concrete frame-bent plant of CAP1400 nuclear power plant considering the high-mode vibration

Biao Liu,Zhengzhong Wang,Bo Zhang,Ningjun Du,Mingxia Gao,Guoliang Bai 국제구조공학회 2023 Steel and Composite Structures, An International J Vol.46 No.2

In order to study the seismic response of the main plant of steel reinforced concrete (SRC) structure of the CAP1400 nuclear power plant under the influence of different high-mode vibration, the 1/7 model structure was manufactured and its dynamic characteristics was tested. Secondly, the finite element model of SRC frame-bent structure was established, the seismic response was analyzed by mode-superposition response spectrum method. Taking the combination result of the 500 vibration modes as the standard, the error of the base reactions, inter-story drift, bending moment and shear of different modes were calculated. Then, based on the results, the influence of high-mode vibration on the seismic response of the SRC frame-bent structure of the main plant was analyzed. The results show that when the 34 vibration modes were intercepted, the mass participation coefficient of the vertical and horizontal vibration mode was above 90%, which can meet the requirements of design code. There is a large error between the seismic response calculated by the 34 and 500 vibration modes, and the error decreases as the number of modes increases. When 60 modes were selected, the error can be reduced to about 1%. The error of the maximum bottom moment of the bottom column appeared in the position of the bent column. Finally, according to the characteristics of the seismic influence coefficient αj of each mode, the mode contribution coefficient γj•Xji was defined to reflect the contribution of each mode to the seismic action.

Finite element modeling of bond-slip performance of section steel reinforced concrete

Biao Liu,Guo-Liang Bai 사단법인 한국계산역학회 2019 Computers and Concrete, An International Journal Vol.24 No.3

The key issue for the finite element analysis (FEA) of section steel reinforced concrete (SRC) structure is how to consider the bond-slip performance. However, the bond-slip performance is hardly considered in the FEA of SRC structures because it is difficult to achieve in the finite element (FE) model. To this end, the software developed by Python can automatically add spring elements for the FE model in ABAQUS to considering bond-slip performance. The FE models of the push-out test were conducted by the software and calculated by ABAQUS. Comparing the calculated results with the experimental ones showed that: (1) the FE model of SRC structure with the bond-slip performance can be efficiently and accurately conducted by the software. For the specimen with a length of 1140 mm, 3565 spring elements were added to the FE model in just 6.46s. In addition, different bond-slip performance can also be set on the outer side, the inner side of the flange and the web. (2) The results of the FE analysis were verified against the corresponding experimental results in terms of the law of the occurrence and development of concrete cracks, the stress distribution on steel, concrete and steel bar, and the P-S curve of the loading and free end.

3D quasi-transient thermo-mechanical analysis for vehicle brake disc

Biao Hu,Xingyan Zhang,Yang Liu,Junjie Yan,Xiaobing Liu,Xin Wang,Richard Sun 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.2

An alternative numerical method is developed to predict the thermo-mechanical behavior of brake disc during braking. Steady-state aerodynamic simulation for entire vehicle with variant speeds are conducted to analyze the convective heat transfer characteristic of the disc surface. Then the transient heat transfer boundary of the disc is obtained by interpolating the steady-state simulation results. Based on that, the transient thermo-mechanical coupled simulation for brake disc is performed via finite element method. With those work, the characteristics of transient temperature field and stress field of the brake disc are analyzed. Meanwhile, the characteristic of contact pressure distribution on friction interface is also obtained. The results show that during the braking process, for any node in the friction areas of the brake disc surface, its temperature rise curve fluctuates like a sawtooth. The temperature field has a significant effect on the stress field of the brake disc, both in distribution and variation. To verify the numerical method and validate the simulation results, a full-scale vehicle brake-thermalperformance test is carried out. By comparison, the simulation results show good agreement with the experimental results. The proposed numerical method enables an efficient and economical way to predict and evaluate the thermo-mechanical behavior of the brake disc in early phase of vehicle development.

Nitric oxide fumigation for control ofwestern flower thrips and its safety to postharvest quality of fresh fruit and vegetables☆

Yong-Biao Liu 한국응용곤충학회 2016 Journal of Asia-Pacific Entomology Vol.19 No.4

Nitric oxide fumigation under ultralow oxygen conditions was studied for controlling western flower thrips and effects on postharvest quality of fresh fruit and vegetables. Four hour fumigationwith 1.0% nitric oxide at 2 °C and 3 h fumigationwith 2.0% nitric oxide at 5 °C achieved complete control of the thrips. The 4 h treatmentwas tested on 10 fresh fruit and vegetables including lettuce, broccoli, pepper, squash, tomato, apple, lemon, orange, peach, and pear. When the treatment was terminated by flushing with nitrogen to dilute nitric oxide before exposing the products to ambient air, the treatment had no negative impact on quality of the products. When the treatment was terminated by flushing with air to allow nitric oxide to reacts with oxygen in the air to form nitrogen dioxide, the treatment caused injuries to themajority of the fresh products. Fresh productswith thick and robust skins were more tolerant than those with thin and delicate skins to nitric oxide fumigation. The 4 h fumigation with 1.0% nitric oxide of strawberries at 2 °C had positive impact on strawberry quality with enhanced firmness, brighter and richer color than the controls. The study demonstrated efficacy of nitric oxide fumigation in controlling western flower thrips, safety to fresh commodities, and benefits to postharvest quality of strawberries.

Low-temperature phosphine fumigation of chilled lettuce under insulated cover for postharvest control of western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae)

Yong-Biao Liu 한국응용곤충학회 2011 Journal of Asia-Pacific Entomology Vol.14 No.3

Pallet-scale phosphine fumigations were conducted on pre-chilled iceberg lettuce under an insulated cover to determine efficacy against western flower thrips, Frankliniella occidentalis, and phytotoxicity to lettuce. Vacuum-cooled commercial iceberg lettuce at 3 °C was sealed in a plastic bag, covered with double-bubble foil insulation, and then fumigated with 484±17 ppm phosphine for 18 h under storage at 20 °C. Lettuce temperature increased from 4.5 °C to 7.2 °C during the course of fumigations. The fumigation treatment was replicated three times and achieved complete control of 3453 western flower thrips. Lettuce quality was evaluated 2 weeks after fumigation and the fumigation had no significant negative impact on lettuce quality. This study demonstrates that insulated cover can be used to keep pre-chilled lettuce at low temperature suitable for low-temperature phosphine fumigation to control western flower thrips on harvested lettuce.

Electronic effects on protective mechanism of electropolymerized coatings based on N-substituted aniline derivatives for mild steel in saline solution

Hao Liu,Baomin Fan,Zining Liu,Xiaoqi Zhao,Biao Yang,Xingwen Zheng,Hua Hao 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.106 No.-

Polyaniline (PANI), poly(N-methylaniline) (PNMA) and poly(N-formylanilide) (PNFA) coatings were fabricatedover mild steel via chronoamperometric strategy in oxalate electrolyte. Scanning electron microscope(SEM), attenuated total reflection infrared spectroscopy (ATR-IR) and X-ray photoelectronspectroscopy (XPS) evidenced the polymerization of monomers. Anticorrosive effects of PANI, PNMAand PNFA coatings for steel substrate were evaluated during long-term immersion in 3.5% NaCl solutionby potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and frequency modulation(EFM). Morphological variation for coated specimens before and after immersion in NaCl solutionwas also monitored by SEM and atomic force microscope (AFM). Differentiated protection capability wereobserved for three coatings following the sequence of PNFA > PNMA > PANI. Through electrochemical andinterfacial analyses, electroactivity and physical barrier were ascertained as the critical factors, especiallythe former one, in the long-term protection capacity. Electroactivity was distinguished by the elevatedapparent current density from non-destructive EFM measurements. Furthermore, electron-donationand -withdrawal effects of N-substituents played an essential role in coating electroactivity. In detail,N-substituents improved the anodic protection and physical barrier of PNMA and PNFA coatings. Particularly, formyl with electron-withdrawal effect reinforced the anodic protection and thus the superiorthe anticorrosion efficiency of PNFA for underlying steel.

Ultralow oxygen treatment for control of western flower thrips, Frankliniella occidentalis (Thysanoptera: Thripidae), on harvested table grapes

Yong-Biao Liu 한국응용곤충학회 2012 Journal of Asia-Pacific Entomology Vol.15 No.2

Exported organic table grapes from the U.S. are currently fumigated with methyl bromide to control quarantined pests such as western flower thrips, Frankliniella occidentalis (Pergande). An alternative treatment which is compatiblewith organic products is needed. In this study, controlled atmospherewith ultralowoxygen (ULO) treatment was studied to control thrips on harvested table grapes. ULO treatments with b0.01 ppm oxygen at 3.3 °C for 1, 2, and 3 days were tested for thrips control. The 3-day ULO treatment achieved complete control of thrips. The treatment was also applied to Thompson seedless and Flame seedless grape varieties and grape quality was evaluated two weeks after the treatment. The ULO treatment had no negative impact on the visual quality of grapes. There were no significant differences in overall grape quality or premiumquality berries between the ULO treatment and the control. The results indicated that the ULO treatment was effective and safe to control western flower thrips on table grapes and had a potential for commercial use.

Temporally Constrained Group Sparse Learning for Longitudinal Data Analysis in Alzheimer's Disease

Jie, Biao,Liu, Mingxia,Liu, Jun,Zhang, Daoqiang,Shen, Dinggang IEEE 2017 IEEE Transactions on Biomedical Engineering Vol.64 No.1

<P>Sparse learning has been widely investigated for analysis of brain images to assist the diagnosis of Alzheimer's disease and its prodromal stage, i.e., mild cognitive impairment. However, most existing sparse learning-based studies only adopt cross-sectional analysis methods, where the sparse model is learned using data from a single time-point. Actually, multiple time-points of data are often available in brain imaging applications, which can be used in some longitudinal analysis methods to better uncover the disease progression patterns. Accordingly, in this paper, we propose a novel temporallyconstrained group sparse learning method aiming for longitudinal analysis with multiple time-points of data. Specifically, we learn a sparse linear regression model by using the imaging data from multiple time-points, where a group regularization term is first employed to group the weights for the same brain region across different time-points together. Furthermore, to reflect the smooth changes between data derived from adjacent time-points, we incorporate two smoothness regularization terms into the objective function, i.e., one fused smoothness term thatrequires that the differences between two successive weight vectors from adjacent time-points should be small, and another output smoothness term thatrequires the differences between outputs of two successive models from adjacent time-points should also be small. We develop an efficient optimization algorithm to solve the proposed objective function. Experimental results on ADNI database demonstrate that, compared with conventional sparse learning-based methods, our proposed method can achieve improved regression performance and also help in discovering disease-related biomarkers.</P>

Genetic Analysis and Molecular Mapping of Gene Associated with Dominant Genic Male Sterility in Rapeseed (Brassica napus L.)

Jun Liu,Deng Feng Hong,Wei Lu,Ping Wu Liu,Qing Biao He,Guang Sheng Yang 한국유전학회 2008 Genes & Genomics Vol.30 No.6

Rs1046AB is a dominant genic male sterility (DGMS) line derived from a spontaneous mutant in Brassica napus. The sterility of this mutant was previously regarded as to be conditioned by the interaction of a dominant male sterility gene Ms and its non-allelic dominant restorer gene Mf (or Rf in previous reports). Recent genetic analyses, however, indicated that Ms and Mf may be allelic. In this research, we confirmed that a multiple allele model should be more appropriate to elucidate the heredity of DGMS line Rs1046AB. Based on this result, the present study emphasized on identifying DNA markers linked to Ms/Mf in an F2 population constructed by crossing Rs1046A with a double haploid (DH) restorer line (19514A). Twenty amplified fragment length polymorphism (AFLP) markers linked to the Ms/Mf locus were identified by combination of bulked segregant analysis (BSA) with AFLP technique. The target locus was detected to be co-segregating with the marker S05T05 and bracketed by two nearest markers, E14M01 and E01M02, with a genetic distance of 0.1 cM and 1.2 cM, respectively. Furthermore, we successfully converted two AFLP markers into sequence characterized amplified region (SCAR) markers. These findings provided direct molecular marker proofs on the inheritance model of this DGMS line, and the high density molecular markers linkage map around the Ms/Mf locus will be more informative for both marker-assisted selection (MAS) of elite male sterile lines and isolation of the Ms/Mf genes by positional cloning in future.