Fatigue Prognosis Analysis on the Cracked Steel Crane Runway Girders Under High Temperature

Huajing Guo,Xiaolong Tong 한국강구조학회 2021 International Journal of Steel Structures Vol.21 No.3

In order to resolve the fatigue fracture problem of the steel crane runway girders (CRGs) with a surface crack under high temperature, fatigue prognosis analysis on the cracked CRGs has been performed. Three dimensions fi nite element models for cracked CRGs have been established using ABAQUS and the fatigue-creep crack propagation of the CRGs under high temperature has been simulated. A fatigue-creep life prediction method for the cracked CRGs at high temperature has been developed based on the obtained numerical results and Saxena theories. The infl uence of runway eccentricity and overloading eff ect on the crack propagation have been studied, respectively. It turns out that the runway eccentricity exhibits little infl uence on propagation of the crack at the weld joint between web plate and lower fl ange of the CRG. The fatigue-creep life of the cracked CRGs at high temperature has been predicted under diff erent wheel loading condition. The fatigue-creep life of CRGs ranges from about 234–48 days under the condition where the wheel loading increases from 300 to 450 kN. The overloading eff ect signifi cantly accelerates the crack propagation and the fatigue-creep life of the CRG under 10% overloading has been shortened about 41.7% compared with that under full loading condition.

Seismic tests of RC shear walls confined with high-strength rectangular spiral reinforcement

Huajing Zhao,Qingning Li,Can Song,Haotian Jiang,Jun Zhao 국제구조공학회 2017 Steel and Composite Structures, An International J Vol.24 No.1

In order to improve the deformation capacity of the high-strength concrete shear wall, five high-strength concrete shear wall specimens confined with high-strength rectangular spiral reinforcement (HRSR) possessing different parameters, were designed in this paper. One specimen was only adopted high-strength rectangular spiral hoops in embedded columns, the rest of the four specimens were used high-strength rectangular spiral hoops in embedded columns, and high-strength spiral horizontal distribution reinforcement were used in the wall body. Pseudo-static test were carried out on high-strength concrete shear wall specimens confined with HRSR, to study the influence of the factors of longitudinal reinforcement ratio, hoop reinforcement form and the spiral stirrups outer the wall on the failure modes, failure mechanism, ductility, hysteresis characteristics, stiffness degradation and energy dissipation capacity of the shear wall. Results showed that using HRSR as hoops and transverse reinforcements could restrain concrete, slow load carrying capacity degeneration, improve the load carrying capacity and ductility of shear walls; under the vertical force, seismic performance of the RC shear wall with high axial compression ratio can be significantly improved through plastic hinge area or the whole body of the shear wall equipped with outer HRSR.

Determination of optimal conditions for ribonucleic acid production by Candida tropicalis no. 121

Huajing Ren,Hanjie Ying,Xiaochun Chen,Jiaming Cao,Lei Li,Jianxin Bai,Yong Chen,Jian Xiong 한국화학공학회 2011 Korean Journal of Chemical Engineering Vol.28 No.8

The experiments were based on multivariate statistical concepts, and response surface methodology (RSM)was applied to optimize the fermentation medium for the production of ribonucleic acid (RNA) by Candida tropicalis no. 121. The process involved the individual adjustment and optimization of various medium components at shake flask level. The two-level Plackett-Burman (PB) design was used to screen the medium components, which significantly influenced RNA production. Among seven variables, the concentrations of molasses, ZnSO_4, and H_3PO_4 were found to be the important factors that significantly affected RNA production (confidence levels above 95%). These factors were further optimized using a central composite design (CCD) and RSM. The optimum values for the critical components were as follows: molasses 47.21 g/L: ZnSO_4 0.048 g/L; H_3PO_4 1.19 g/L. Under optimal conditions, RNA production was 2.56 g/L, which was in excellent agreement with the predicted value (2.561 g/L), and led to a 2.1-fold increase compare with that using the original medium in RNA production.

Fault Detection for a Class of Networked Nonlinear Systems Subject to Imperfect Measurements

Xiongbo Wan,Huajing Fang,Fang Yang 제어·로봇·시스템학회 2012 International Journal of Control, Automation, and Vol.10 No.2

This paper addresses the problem of fault detection (FD) for discrete-time networked systems with global Lipschitz conditions and imperfect measurements. By using Bernoulli stochastic variables and a switching signal, a unified model is proposed to describe four kinds of imperfect measurements, that is, access constraints, time delays, packet dropouts, and signal quantization. We aim to design a fault detection filter (FDF) such that, for all external disturbances and imperfect measurements, the error be-tween the residual and fault is made as small as possible. The addressed FD problem is then converted into an auxiliary H∞ filtering problem for discrete-time stochastic switched systems with multiple time-varying delays. By applying Lyapunov-Krasovskii approach, a sufficient condition for the existence of the FDF is derived in terms of certain linear matrix inequalities (LMIs). When these LMIs are feasible, the explicit expression of the desired FDF can also be characterized. A numerical example is exploited to show the effectiveness of the results obtained.

Research on prefabricated concrete beam-column joint with high strength bolt-end plate

Li Shufeng,Zhao Di,Li Qingning,Zhao Huajing,Zhang Jiaolei,Yuan Dawei 국제구조공학회 2020 Structural Engineering and Mechanics, An Int'l Jou Vol.74 No.3

Many prefabricated concrete frame joints have been proposed, and most of them showed good seismic performance. However, there are still some limitations in the proposed fabricated joints. For example, for prefabricated prestressed concrete joints, prefabricated beams and prefabricated columns are assembled as a whole by the pre-stressed steel bar and steel strand in the beams, which brings some troubles to the construction, and the reinforcement in the core area of the joints is complex, and the mechanical mechanism is not clear. Based on the current research results, a new type of fabricated joint of prestressed concrete beams and confined concrete columns is proposed. To study the seismic performance of the joint, the quasi-static test is carried out. The test results show that the nodes exhibit good ductility and energy dissipation. According to the experimental fitting method and the “fixed point pointing” law, the resilience model of this kind of nodes is established, and compared with the experimental results, the two agree well, which can provides a certain reference for elasto-plastic seismic response analysis of this type of structure. Besides, based on the analysis of the factors affecting the shear capacity of the node core area, the formula of shear capacity of the core area of the node is proposed, and the theoretical values of the formula are consistent with the experimental value.

Matrine Suppresses Pancreatic Fibrosis by Regulating TGF-β/Smad Signaling in Rats

Pi Liu,Luhong Zhu,Guohui Zou,Huajing Ke 연세대학교의과대학 2019 Yonsei medical journal Vol.60 No.1

Purpose: This study aimed to elucidate the molecular mechanisms of the anti-pancreatic fibrosis effects of matrine in rats. Materials and Methods: Trinitrobenzene sulfonic acid was administrated to rats to establish a pancreatic fibrosis model. Rats weredivided into four groups: Control, Sham, Model, and Matrine (n=8). Hematoxylin-eosin staining, Masson staining, and Azan stainingwere performed to evaluate pancreatic fibrosis. Expression of transforming growth factor-β1 (TGF-β1), α-smooth muscle actin(α-SMA), and collagen I in pancreatic tissues was evaluated by immunohistochemical staining. mRNA and protein levels of TGF-βreceptor 1 (TβR1), TβR2, and Smad2 in pancreatic tissues were determined by RT-PCR and Western blot, respectively. Results: In the model group, hyperplasia of glandules around the glandular ducts, mitochondrial swelling of acinous cells, andsevere fibrosis were found. Interestingly, in the Matrine group, mitochondrial swelling was only found in a small number of acinouscells, and the fundamental structures of pancreatic tissues were intact. Moreover, pancreatic fibrosis was markedly alleviated. Comparing to the Sham group, expression of α-SMA, TGF-β1, and collagen I was sharply elevated in the Model group (p<0.05);however, their expressions were much lower in the Matrine group, compared to the Model group (p<0.05). Compared with theSham group, mRNA and protein levels of Smad2, TβR1, and TβR2 in the Model group were notably raised (p<0.05). However,their high expression was significantly downregulated in the Matrine group (p<0.05). Conclusion: Matrine suppressed pancreatic fibrosis by regulating TGF-β/Smad signaling in rats.

Anaerobic Ammonium-Oxidizing Bacteria in Cow Manure Composting

( Tingting Wang ),( Lijun Cheng ),( Wenhao Zhang ),( Xiuhong Xu ),( Qingxin Meng ),( Xuewei Sun ),( Huajing Liu ),( Hongtao Li ),( Yu Sun ) 한국미생물생명공학회(구 한국산업미생물학회) 2017 Journal of microbiology and biotechnology Vol.27 No.7

Composting is widely used to transform waste into valuable agricultural organic fertilizer. Anaerobic ammonium-oxidizing (anammox) bacteria play an important role in the global nitrogen cycle, but their role in composting remains poorly understood. In the present study, the community structure, diversity, and abundance of anammox bacteria were analyzed using cloning and sequencing methods by targeting the 16S rRNA gene and the hydrazine oxidase gene (hzo) in samples isolated from compost produced from cow manure and rice straw. A total of 25 operational taxonomic units were classified based on 16S rRNA gene clone libraries, and 14 operational taxonomic units were classified based on hzo gene clone libraries. The phylogenetic tree analysis of the 16S rRNA gene and deduced HZO protein sequences from the corresponding encoding genes indicated that the majority of the obtained clones were related to the known anammox bacteria Candidatus “Brocadia,” Candidatus “Kuenenia,” and Candidatus “Scalindua.” The abundances of anammox bacteria were determined by quantitative PCR, and between 2.13 × 10⁵ and 1.15 × 10⁶ 16S rRNA gene copies per gram of compost were found. This study provides the first demonstration of the existence of anammox bacteria with limited diversity in cow manure composting.

NF-κB in Cellular Senescence and Cancer Treatment

Hua Jing,Soyoung Lee 한국분자세포생물학회 2014 Molecules and cells Vol.37 No.3

The NF-κB pathway transcriptionally controls a large set of target genes that play important roles in cell survival, inflammation, and immune responses. While many studies showed anti-tumorigenic and pro-survival role of NF-κB in cancer cells, recent findings postulate that NF-κB participates in a senescence-associated cytokine response, thereby suggesting a tumor restraining role of NF-κB. In this review, we discuss implications of the NF-κB signaling pathway in cancer. Particularly, we emphasize the connection of NF-κB with cellular senescence as a response to chemotherapy, and furthermore, present examples how distinct oncogenic network contexts surrounding NF-κB produce fundamentally different treatment outcomes in aggressive B-cell lymphomas as an example.