Nonstructural Influence Factors of Dynamic Load Allowance for Concrete Beam Bridges

Chenguang Liu,Zonglin Wang,Qingfei Gao 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.5

Studies show that nonstructural parameters, such as pavement conditions or load patterns, have greater influences on the dynamic load allowance (DLA) of bridges than structural parameters. For pavement roughness effects, the values of DLA caused by roughness profiles are calculated by a self-compiled program. The results showed that the values of DLA are discrete even if they are caused by roughness profiles that belong to the same power spectral density (PSD) grade. The PSD grade method for pavement conditions has limitations when it is used in the analysis of DLA. Statistical analysis was also carried out on these DLA results. The statistical analysis indicated that the values of DLA followed a normal distribution when they were excited by roughness profiles that belong to the same grade. For the influence of vehicle string loads on DLA, an improved optimization approach based on a genetic algorithm for the largest DLA is presented. A new method is used to calculate the fitness value in the genetic algorithm (GA) method, which could substantially reduce calculation time. The new approach is able to obtain the most unfavorable arrangement of the vehicle string and estimate the largest DLA caused by it.

Self-assembled nanoparticles based on linoleic-acid modified carboxymethyl-chitosan as carrier of adriamycin (ADR)

Chenguang Liu,Wenwen Fan,Xiguang Chen,Chengsheng Liu,Xianghong Meng,Hyun Jin Park 한국물리학회 2007 Current Applied Physics Vol.7 No.s1

Linoleic-acid (LA) is covalently conjugated to carboxymethyl-chitosan via a 1-ethyl-3-(3-dimethylaminopropyyl)-carbodiimide-med-iated (EDC-mediated) reaction to generate self-aggregated chitosan nanoparticles by sonication. The average diameter of the particles isloading experiments indicate that the loading capacity and eciency increase with increasing concentration of ADR. ADR is slowlyreleased from chitosan self-aggregates for about 3 days. Furthermore, the eects of drug controlled release become more obvious onincreasing the pH value.

Application of model reduction technique and structural subsection technique on optimal sensor placement of truss structures

Chenguang Huang,Lingling Lu,Lijuan Liao,Yanpeng Wei,Yanchi Liu,Xi Wang 국제구조공학회 2015 Smart Structures and Systems, An International Jou Vol.15 No.2

An optimal sensor placement (OSP) method based on structural subsection technique (SST) and model reduction technique was proposed for modal identification of truss structures, which was conducted using genetic algorithm (GA). The constraints of GA variables were determined by SST in advance. Subsequently, according to model reduction technique, the optimal group of master degrees of freedom and the optimal objective function value were obtained using GA in a case of the given number of sensors. Correspondingly, the optimal number of sensors was determined according to optimal objective function values in cases of the different number of sensors. The proposed method was applied on a scaled jacket offshore platform to get its optimal number of sensors and the corresponding optimal sensor layout. Then modal kinetic energy and modal assurance criterion were adopted to evaluate vibration energy and mode independence property. The experiment was also conducted to verify the effectiveness of the selected optimal sensor layout. The results showed that experimental modes agreed reasonably well with numerical results. Moreover the influence of the proposed method using different optimal algorithms and model reduction technique on optimal results was also compared. The results showed that the influence was very little.

Viscosity evaluation of Fe–Ni–Co ternary alloy from the measured binary systems

Yanhui Liu,Xuewei Lv,Chenguang Bai,Pingsheng Lai,JinSheng Wang 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.30 No.-

The iso-viscosity curves of liquid Fe–Ni–Co ternary alloys at 1600 8C were investigated with consideringthe excess viscosity of ternary alloy by the means of three models (Kohler, Toop and Chou) from themeasured sub-binary data in this work. Excess viscosities were used instead of excess thermodynamicproperties in geometrical models, and the excess viscosities of the sub-binary systems were fit by usingthe 3rd degree (n = 3) Redlich–Kister polynomial. The increase of Ni content results in the decrease of theviscosity of the ternary alloy, while Fe has opposite effect. When the molar content of Ni within the alloydoes not exceed 50%, the increase of Co lowers the viscosity. Once its content is above 50%, Co canpromote the increase of the viscosity of the ternary alloy. Similarity coefficients of the Fe–Ni, Fe–Co andNi–Co three binary systems mentioned in the Chou model have been calculated and their values are 0.82,0.20 and 0.47, respectively, showing that the Fe–Ni–Co ternary system is not exactly the ‘‘Kohler model’’or ‘‘Toop model’’, so both Kohler model and Toop model cannot obtain the accurate predicted values. Thepredicted iso-viscosity curves calculated by the Chou model should be recommended. Some activationenergies of the ternary alloy were calculated by the three models and compared with three sub-binarysystems, and the evaluated activation energies calculated by the Chou model should be recommended. Except the sample AE3 and AE6, other activation energy values predicted by three different models aresimilar by a narrow margin. The activation energies for AE3 and AE6 are the lowest and highest,respectively, because of the mix effect of the ternary alloy.

Hydrogenation of isoprene over gold supported on CeO2, ZrO2, SiO2 and N–SiO2

Kang Yang,Chenguang Liu 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.28 No.-

In gold catalysis, the charge state issue is of particular importance but still under debate. In this work,four categories of active site (anionic Au on ZrO2, cationic Au on SiO2, metallic Au on functionalized SiO2(N–SiO2) and anionic Au with OH groups on CeO2) were prepared. After evaluation, the charge stateeffect was observed. Negatively charged Au on irreducible monoclinic ZrO2 benefits the selectivehydrogenation of isoprene, meaning ‘‘charge sensitive reaction’’ was observed. However, the selectivityis not dependent on different active site. No isopentane was produced under experimental conditions.

Experimental Study on Divergent Magnetic Fluid Seal with Small Clearance and Double Magnetic Source

Xiaolong Yang,Chenguang Yang,Gang Liu 한국자기학회 2022 Journal of Magnetics Vol.27 No.1

In order to solve the problem of poor sealing performance of rotating machinery under the condition of small clearance, a new type of divergent magnetic fluid seal device with small clearance and double magnetic source is designed in this paper. The effect of magnetic fluid injection, tooth number and sealing clearance on the sealing pressure resistance of dual magnetic source divergence were studied and compared with the experimental value of ordinary magnetic fluid seal. The experiment results show that the pressure resistance ability of divergent magnetic fluid seal is at least 3 times that of ordinary magnetic fluid seal, which verifies the correctness of divergent magnetic seal with small clearance and double magnetic source pressure resistance theory, and has important theoretical guiding significance for solving the problem of poor magnetic fluid seal performance under small clearance.

Ultimate strength performance of tankers associated with industry corrosion addition practices

김도균,김한별,Xiaoming Zhang,Chenguang Liu,백점기 대한조선학회 2014 International Journal of Naval Architecture and Oc Vol.6 No.3

In the ship and offshore structure design, age-related problems such as corrosion damage, local denting, and fatigue damage are important factors to be considered in building a reliable structure as they have a significant influence on the residual structural capacity. In shipping, corrosion addition methods are widely adopted in structural design to prevent structural capacity degradation. The present study focuses on the historical trend of corrosion addition rules for ship structural design and investigates their effects on the ultimate strength performance such as hull girder and stiffened panel of double hull oil tankers. Three types of rules based on corrosion addition models, namely historic corrosion rules (pre-CSR), Common Structural Rules (CSR), and harmonised Common Structural Rules (CSR-H) are considered and compared with two other corrosion models namely UGS model, suggested by the Union of Greek Shipowners (UGS), and Time-Dependent Corrosion Wastage Model (TDCWM). To identify the general trend in the effects of corrosion damage on the ultimate longitudinal strength performance, the corrosion addition rules are applied to four representative sizes of double hull oil tankers namely Panamax, Aframax, Suezmax, and VLCC. The results are helpful in understanding the trend of corrosion additions for tanker structures.

Research on Natural Gas Leakage Diffusion of Urban Underground Pipeline and its Explosion Hazard

Dai Wang,Peng Liu,Chenguang Hua,Hai Zhang,Chenyang Shi,Jianmei Du 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.2

For the risk of gas leakage and explosion that may occur during the serviceability of urban natural gas pipeline, based on the numerical simulation conducted by FLACS, the gas leakage, explosion and disaster risk under the different speed of wind are mainly studied with local climate characteristics for actual urban street. The results show that the wind speed has an obvious effect on the gas leakage and diffusion, the deviation of gas leakage direction is not obvious for the smaller speed of wind at the initial stage, the horizontal diffusion range gradually increases with the increase of wind speed, while the vertical diffusion range gradually decreases, and the volume of gas at the limit concentration of combustion and explosion gradually decreases. In urban buildings, the overpressure load of higher buildings is lower. After the explosion, the peak overpressure at the same monitoring point decreases with the increase of wind speed. With the increase of distance from the building to the explosion location, the overpressure load on the building decreases and the oscillation effect of overpressure load is relatively gentle. The thermal radiation after burning has great influence on the surrounding buildings and downwind position, especially the buildings around the leakage point.

The Transition of Molecular Alignment of Poly(ethylene oxide) Film via Thermal Annealing

Hangyu Zhang,Guangzhu Ding,Kun Wu,Chenguang Cai,Jieping Liu 한국고분자학회 2022 Macromolecular Research Vol.30 No.4

The molecular alignment of polymer film has attracted a lot of attentions due to its complicated process affected by processing conditions and dominating polymer applications. Here we demonstrate that the annealing process can not only change the surface morphology of annealed poly(ethylene oxide) (PEO) film significantly but also induce the formation of highly oriented lamellar structure. It indicates that sheaf-like and cluster banding morphology can be both found obviously on the surface of pristine film. However, there is only sheaf-like morphology and sporadical cluster banding cannot be found obviously on the surface of annealed film. Then, there are both tilt and flat-on orientations of PEO crystalline for pristine film. But, single flat-on orientation of PEO crystalline is present and tilt orientation mode is absent for annealed films. Furthermore, the transition of molecular alignment of PEO film via thermal annealing cannot be affected by the thickness and temperature.

The Uneven Distribution of Mating Type Genes in Natural and Cultivated Truffle Orchards Contributes to the Fructification of Tuber indicum

( Qiang Li ),( Yu Fu ),( Qun Sun ),( Pierre Sourzat ),( Mei Yang ),( Chengyi Liu ),( Hao Tan ),( Lei Ye ),( Jie Zou ),( Chenguang Wu ),( Bo Zhang ),( Xiaolin Li ) 한국균학회 2018 Mycobiology Vol.46 No.1

The aim of this study was to investigate the pattern of distribution of mating type (MAT) genes of Tuber indicum in ectomycorhizosphere soils from natural T. indicum-producing areas and cultivated truffle orchards and ascocarp samples from different regions. Quantitative real-time PCR and multiplex PCR were used to weight the copy numbers of MAT1-1-1 and MAT1-2-1 in natural truffle soils and cultivated orchard soils. The effect of limestone on the pattern of truffle MAT genes and the correlation between soil properties and the proportion of MAT genes were also assessed. These results indicated that an uneven and nonrandom distribution of MAT genes was common in truffle-producing areas, cultivated truffle orchards, and ascocarps gleba. The competition between the two mating type genes and the expansion of unbalanced distribution was found to be closely related to truffle fructification. Limestone treatments failed to alter the proportion of the two mating type genes in the soil. The content of available phosphorus in soil was significantly correlated with the value of MAT1-1-1/MAT1-2-1 in cultivated and natural ectomycorhizosphere soils. The application of real-time quantitative PCR can provide reference for monitoring the dynamic changes of mating type genes in soil. This study investigates the distributional pattern of T. indicum MAT genes in the ectomycorhizosphere soil and ascocarp gleba from different regions, which may provide a foundation for the cultivation of T. indicum.