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Applications of sediment sudden deposition model based on the third-generation numerical model for shallow water wave

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Acta Oceanologica Sinica 2007年第3期26卷 142-149页

作者： BAI Yuchuan ZHANG Yinqi ZHANG Bin Institute of Sediment on River and Coast engineering Tianjin University Tianjin 300072 China China Communication Construction corporation First Harbor consultants Co. Ltd Tianjin 300222 China

The existing numerical models for nearshore waves are briefly introduced, and the third-generation numerical model for shallow water wave, which makes use of the most advanced productions of wave research and has been adapted well to be used in the environment of seacoast, lake and estuary area, is particularly discussed. The applied model realizes the significant wave height distribution at different wind directions. To integrate the model into the coastal area sediment, sudden deposition mechanism, the distribution of average silt content and the change of sediment sudden deposition thickness over time in the nearshore area are simulated. The academic productions can give some theoretical guidance to the applications of sediment sudden deposition mechanism for stormy waves in the coastal area. And the advancing directions of sediment sudden deposition model are prospected.

关键词： Boussinesq equation mild-slope equation third-generation numerical model for shallow water wave sedimentsudden deposition

Preparation of nanometer yellow iron and its UV absorption capacity

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Journal of University of Science and Technology Beijing 2007年第1期14卷 72-76页

作者： Chunbao Sun Beihai Zhou Nan Li Ruiming Wang Civil and Environment engineering School University of Science and Technology Beijing Beijing 100083 China Semiconductor Manufacture international corporation （tianjin） Tianjin 300380 China

The nanometer yellow iron oxide was prepared by oxidizing Fe（OH）2 with air, which was verified with XRD and TEM. The result shows that nanometer yellow iron oxide is spindle-shaped and well-distributed with a long axis of 150-200 nm and short axis of 40-50 nm. Ultraviolet （UV） transmittance of the iron oxide shows the great effect of concentration on both transparency and UV ab- sorption, and it has been proven that iron oxide with a concentration of 0.025wt% is preferred. The spectrum of XRD indicates that it is goethite. When the yellow iron is dispersed in sol, given that the wavelength of UV is less than 300 nm, its UV absorption capacity is superior to those of ZnO and TiO2. The absorption capacity of the yellow iron is less than TiO2 and more than ZnO as the wavelength of UV is 300-400 nm.

关键词： yellow iron oxide nanometer particle UV absorption transparency

Fouling corrosion in aluminum heat exchangers

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Chinese Journal of Aeronautics 2015年第3期28卷 954-960页

作者： Su Jingxin Ma Minyu Wang tianjing Guo Xiaomei Hou Liguo Wang Zhiping tianjin Key Laboratory for Civil Aircraft Airworthiness and Maintenance Civil Aviation University of China Aircraft Maintenance and engineering corporation Beijing Capital International Airport

Abstract Fouling deposits on aluminum heat exchanger reduce the heat transfer efficiency and cause corrosion to the apparatus. This study focuses on the corrosive behavior of aluminum cou- pons covered with a layer of artificial fouling in a humid atmosphere by their weight loss, Tafel plots, electrochemical impedance spectroscopy （EIS）, and scanning electron microscope （SEM） observations. The results reveal that chloride is one of the major elements found in the fouling which damages the passive film and initiates corrosion. The galvanic corrosion between the metal and the adjacent carbon particles accelerates the corrosive process. Furthermore, the black carbon favors the moisture uptake, and gives the dissolved oxygen greater chance to migrate through the fouling layer and form a continuous diffusive path. The corrosion rate decreasing over time is conformed to electrochemistry measurements and can be verified by Faraday＇s law. The EIS results indicate that the mechanism of corrosion can be interpreted by the pitting corrosion evolution mechanism, and that pitting was observed on the coupons by SEM after corrosive exposure.

关键词： Aluminum EIS Heat exchanger Pitting corrosion Tafel plots

Analysis of cracks origin behaviors during sulfide stress corrosion (SSC) in HSLA steel at different temperatures by electrochemical noise

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Journal of Iron and Steel Research international 2022年第11期29卷 1836-1845页

作者： Xiao-hua Li Chen-xi Liu Biao He Chuan-tao Lv Zhi-ming Gao Yong-chang Liu School of Mechanical engineering Tianjin University of Technology and EducationTianjin 300222China State Key Lab of Hydraulic engineering Simulation and Safety School of Materials Science and EngineeringTianjin UniversityTianjin 300350China tianjin Pipe corporation Tianjin 300301China

The sulfide stress corrosion(SSC)behaviors of the high strength low alloy steel at the different temperatures were investigated by the microstructural observation and electrochemical noise(EN)*** the corrosion temperature increasing from 20 to 40℃,SSC ruptured time is *** increase in corrosion temperature results in the decrease of the saturation solubility of H_(2)S in the solution and thus increases pH value of *** increase in corrosion temperature decreases the size of the holes and cracks in the corrosion product film on the surface of the sample,which is due to the formation of the dense FeS corrosion product *** current kurtosis results indicate that the time for the first occurrence of crack initiation is postponed by the increase in the corrosion *** standard deviation of current noise signals,current kurtosis,power spectral density and energy distribution plot results shows a great consistency,which suggests that EN analysis method can reflect SSC behaviors in real time.

关键词： Sulfide stress cracking High strength low alloy(HSLA)steel Electrochemical noise Corrosion temperature Hydrogen sulfide corrosion products

Effect of pH and applied stress on hydrogen sulfide stress corrosion behavior of HSLA steel based on electrochemical noise analysis

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Journal of Iron and Steel Research international 2023年第12期30卷 2531-2540页

作者： Xiao-hua Li Chen-xi Liu Teng Zhang Chuan-tao Lv Jiang-cheng Liu Ran Ding Zhi-ming Gao Rui Wang Yong-chang Liu School of Mechanical engineering Tianjin University of Technology and EducationTianjin300222China State Key Lab of Hydraulic engineering Simulation and Safety School of Materials Science&EngineeringTianjin UniversityTianjin300350China Southwestern Institute of Physics Chengdu610041SichuanChina tianjin Pipe corporation Tianjin300301China

The influence mechanism of pH and the externally applied stress on sulfide stress corrosion cracking behavior based on the joint analysis of the in situ electrochemical noise and microstructure was *** results showed that{\mathrm{H}}^{+}in solution changes the composition and structure of corrosion product film by affecting the concentration of{\mathrm{S}}^{2-}and{\mathrm{Fe}}^{2+}near the anode *** the pH increased from 2.6 to 3.6 and 4.6,the corrosion product film changed from porous Mackinawite to dense and stable *** change in corrosion product type delayed the crack initiation time by 10.5 and 45.5 h,while the uniform corrosion time was prolonged by 6.1 and 46 h,respectively,delaying SSC *** increasing the applied stress,the local plastic deformation on the material surface increases the porosity and crack rate of the corrosion product film and becomes a fast propagation channel for SSC *** the applied stress is 110%of the actual yield strength of the material,the initiation time of stress corrosion cracking is 6 and 18.1 h earlier than that of 90%and 100%,*** local corrosion time was extended by 23.5 and 8.2 h,respectively,accelerating SSC behavior.

关键词： Sulfide stress cracking Electrochemical noise pH-Stress High strength low alloy steel

Comparison of microwave- and thermal-assisted rock fragmentation methods at different temperatures and loading rates

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international Journal of Mining Science and Technology 2024年第6期34卷 799-819页

作者： Wei Yao Shuai Wang Bangbiao Wu Ying Xu Kaiwen Xia State Key Laboratory of Hydraulic engineering Intelligent Construction and Operation School of Civil EngineeringTianjin UniversityTianjin 300072China China Railway Design corporation Tianjin 300308China Institute of Geosafety School of Engineering and TechnologyChina University of GeosciencesBeijing 100083China

Understanding the effects of microwave irradiation and thermal treatment on the dynamic compression and fragmentation properties of rocks is essential to quantify energy consumption in rock *** this study,Fangshan granite(FG)specimens were exposed to microwave irradiation and heat *** damage of FG specimens induced by these two methods was compared using X-ray CT scanning and ultrasonic wave *** temperatures of FG after microwave irradiation and thermal treatment were effectively evaluated using a newly proposed technique.A novelty method for precisely determining the geometric features of fragments is developed to estimate the fragmentation ***,the dynamic uniaxial compressive strength(UCS),the dynamic fragmentation characteristics,and the fragmentation energy of FG after these two pretreatment methods can be reasonably *** noticeable distinction of loading rate effect on the dynamic UCS of FG between these two pretreatment methods is first observed.A relationship is established between the dynamic UCS and the damage induced by microwave irradiation and heat ***,fragmentation energy fan analysis is introduced to accurately compare the fragmentation properties of FG after two pretreatment methods in dynamic compression tests.

关键词： Fangshan granite Dynamic experiments Microwave irradiation Thermal treatment Loading rate Fragmentation

Modeling of an Impinging Oxygen Jet on Molten Bath Surface in 150t EAF

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Journal of Iron and Steel Research international 2011年第9期18卷 13-20页

作者： HE Chun-lai ZHU Rong DONG Kai QIU Yong-quan SUN Kai-ming Metallurgical and Ecological engineering School University of Science and Technology Beijing Beijing 100083 China tianjin Pipe (Group) corporation Tianjin 300301 China

A transient three-dimensional mathematical model has been developed to analyze the three-phase flow in a 150 t EAF （electric arc furnace） using oxygen. VOF （multiphase volume of fluid） method is used to simulate the behaviors of molten steel and slag. Numerical simulation was conducted to clarify the transient phenomena of oxygen impingement on molten bath. When oxygen jet impinges on the surface of molten bath, the slag layer is broken and the penetrated cavity in molten steel is created. Simultaneously, the wave is formed at the surface of uncovered steel on which the slag layer is pushed away by jet. The result of numerical simulations shows that the area and velocity of uncovered steel created by impingement, jet penetration depth change from 0. 10 m2 , 0. 012 5 m/s, 3.58 cm to 0.72 m2 , 0. 1445 m/s, 11.21 cm, when the flow rate of an oxygen lance varies from 500 to 2000 m3/h. The results have been validated against water model experiments. More specially, the relation between the penetration depth and oxygen flow rate predicted by numerical simulation has been found to agree well with that concluded by water model.

关键词： electric arc furnace three-phase flow numerical simulation

Rational argon stirring for a 150-t ladle furnace

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international Journal of Minerals,Metallurgy and Materials 2009年第4期16卷 383-386页

作者： Hai-yan Tang Jing-she Li Cui-hong Xie Shu-feng Yang Kai-ming Sun De-song Wen School of Metallurgical and Ecological engineering University of Science and Technology Beijing Beijing 100083 China Steelmaking Plant of tianjin Pipe corporation Ltd. Tianjin 300301 China

Based on the principle of similarity, water modeling experiments were carried out for a 150-t ladle furnace. The rational parameters of argon stirring were determined as the optimized positions of nozzles, top area of the porous brick, and gas flow rate. The following results are obtained： 1） the optimized positions of two nozzles are at 0.333R （R refers to the radius of the ladle at bottom） with an angle of 135°; 2） the top diameter of the porous brick should be 130 mm; 3） the flow rate of gas should be 25.0-30.6 m^3/h. The plant trial shows that the improved process is effective in enhancing the cleanliness of round billets. The total oxygen content, microinclusions, and macroinclusions in round billets are reduced by 12.5%, 8.2%, and 20%, respectively.

关键词： ladle furnace argon stirring refining inclusions

Estimation of Aleatory Randomness by S_(a)(T_(1))-Based Intensity Measures in Fragility Analysis of Reinforced Concrete Frame Structures

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Computer Modeling in engineering & Sciences 2022年第1期130卷 73-96页

作者： Yantai Zhang Yongan Shi Baoyin Sun ZhengWang College of Civil engineering Nanjing Forestry UniversityNanjing210037China Arup international consultants(Shanghai)Co. Ltd.Shanghai200031China College of Civil and Transportation engineering Hohai UniversityNanjing210098China Power China Huadong engineering corporation Limited(HDEC) Hangzhou311122China

Based on the multiple stripes analysis method,an investigation of the estimation of aleatory randomness by S_(a)(T_(1))-based intensity measures(IMs)in the fragility analysis is carried out for two typical low-and mediumrise reinforced concrete(RC)frame structures with 4 and 8 stories,*** sensitivity of the aleatory randomness estimated in fragility curves to various S_(a)(T_(1))-based IMs is analyzed at three damage limit states,i.e.,immediate occupancy,life safety,and collapse *** addition,the effect of characterization methods of bidirectional ground motion intensity on the record-to-record variability is *** is found that the damage limit state of the structure has an important influence on the applicability of the ground motion *** S_(a)(T_(1))-based IMs,considering the effect of softened period,can maintain lower record-to-record variability in the three limit states,and the S_(a)(T_(1))-based IMs,considering the effect of higher modes,do not show their advantage over S_(a)(T_(1)).Furthermore,the optimal multiplier C and exponentαin the dual-parameter ground motion IM are proposed to obtain a lower record-to-record variability in the fragility analysis of different damage limit ***,the improved dual-parameter ground motion IM is applied in the risk assessment of the 8-story frame structure.

关键词： RC frame structure intensity measure fragility analysis record-to-record variability softened period risk assessment