bluuebunny/crossref_metadata_2025 huggingface dataset:
The Applied Research of Decoupling Control Algorithm in Gas Mixing Process
Authors: Shao Zhong Liang
Published: March 2013

It is difficult to get satisfied effects using conventional instruments to control the caloric value of the mixed-gas. A hybrid intelligent control strategy is presented in this paper in order to solve the coupling problem that exists between the calorific value control and pressure control. This strategy partitions the whole control system into gas–pressurized machine’s post pressure control loop and control loop of pressure decoupling .In the former decoupling control loop, in order to realize the stability of the calorific value and restrain the fluctuation of the mixing pressure, a decoupling controller is designed by combining the fuzzy control and the expert control. The result of real-time control showed the method obviously enhanced the control accuracy and reduced the undulation of pressure and calorific value and fulfilled the request of customer.
An Experimental Study of Steam Gasification of Biomass over Precalcined Copper Slag Catalysts
Authors: Deng Shuang Hui , Hu Jian Hang , Wang Hua , Li Juan Qin , Hu Wei
Published: March 2013

Biomass gasification was separated from catalytic pyrolysis in a two-stage fixed bed reactor with precalcined copper slag catalysts placed in a secondary reactor. The effects of gasification temperature (720-950°C), steam to biomass (S/B) mass ratio (0-2g/g), precalcined copper slag to biomass (C/B) mass ratio (0-2g/g) and copper slag precalcined at different temperatures (800-1000°C) on characteristics of biomass gasification were investigated. The experimental results show that the increase of gasification temperature, S/B mass ratio, C/B mass ratio and precalcination temperature are all favorable for raising gasification efficiency and enhancing the H2 production. With copper slag precalcined at 1000°C for 5 hours as catalyst under the experimental conditions examined, the H2 content, the hydrogen yield, the gas yield and the gasification efficiency reach the maximum of 59.16%, 0.72 Nm3/kg, 1.22 Nm3/kg and 77.56%,respectively.
Coaled Carbon-Based Solid Acid: a New and Efficient Catalyst for Click Synthesis of 3,4-Dihydropyrimidin-2(1H)-Ones under Solvent-Free Conditions
Authors: Liu Wan Yi , Liu Ning , Zheng Rui Yuan , Li Bing , Zhang Xia , Liang Shi Jiao , Wang Zheng
Published: March 2013

Coaled carbon-based solid acid (CCBSAC) is reported as a new, efficient and recyclable catalyst for the regioselective multicomponent synthesis of dihydropyrimidin-2(1H)-ones from aldehydes, β-ketoesters and urea or thiourea under solvent-free conditions. The structure and thermal stability of CCBSAC which resulted from ultra-clean coal resources mainly were characterized by IR, XRD, and TG. Nineteen dihydropyrimidin-2(1H)-ones examples were prepared and this catalyst could recycle up to 4 consecutive runs without losing its efficiency. The high yields of products, short reaction times, ease of work-up and clean procedure will make the present method a useful and important addition to the previous methodologies for the synthesis of dihydropyrimidin-2(1H)-ones.
Effect of Different Aromatic Carboxylic Acid Ligands on the Catalytic Activities of Metal-Organic Frameworks
Authors: Wang Li Ping , Wang Gong Ying , Wang Fan , Wang Pin Hua
Published: March 2013

Metal-organic frameworks based on Zn2+ and different aromatic carboxylic acid ligands were prepared and characterized by X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. They were then used as the catalysts for the transesterification between diphenyl carbonate (DPC) and 1, 4-butyldiol (1, 4-BD) to polycarbonate diol (PCDL). Their catalytic activities in the transesterification process were evaluated by the yield of phenol, and their catalytic activities in the polycondensation process were determined by the number-average molecular weight (Mn) and the hydroxyl value.
La-ZrO2 and Ru-ZrO2 Promoted Co/SiO2 Catalysts for Fischer-Tropsch Synthesis
Authors: Bungmek Waritsara , Kongkinka Passakorn , Chotiwan Siwaruk , Viravathana Pinsuda
Published: March 2013

The performance of ZrO2-La promoted silica supported cobalt catalyst (100Co/15ZrO2/ 100Aerosil/0.66La) was compared to the ZrO2-Ru promoted one, 100Co/15ZrO2/100Aerosil/0.66Ru, in Fischer-Tropsch synthesis (FTS). These catalysts were prepared by co-precipitation and incipient wetness impregnation methods. The characterization by XRD confirmed the cobalt phase of Co3O4 in both catalysts. For their catalytic activity on FTS reaction, the results preliminarily showed the higher methane fraction (60-80%) and lower C2-C4(10-20%) and C5+(10-20%) fractions in ZrO2-La promoted catalyst compared to the fractions of methane (20-40%), C2-C4(20-50%), and C5+(10-60%) from the ZrO2-Ru promoted catalyst. During reaction, the maximum n-paraffin selectivity of 40% was at C3and the hydrocarbon chain was up to C6for the ZrO2-La promoted catalyst. For the ZrO2-Ru promoted catalyst, the result showed the maximum n-paraffin of C3at 30 min of reaction time. When the reaction time increased, the maximum n-paraffin selectivity shifted toward higher C number but levelled off (15%) and the hydrocarbon chain was up to C16.
Preparation of Light-Color Rosin and Preliminary Analysis of Decoloration Mechanism
Authors: Zeng Yu Feng , Jiang Zhang Hua , Qin Li Qin , Tao Ping Fang
Published: March 2013

Color of rosin is an important evaluation quality index. A process for preparing light-color rosin by adding different chemical additives in the reaction was studied. The results showed that the best light-color rosin can be produced by adding TM430 and TM923. Mechanism of decoloration was studied by ultraviolet spectra. The Gardner color of rosin was reduced from 7 to 2 and the acid value and softening point changed a little where the TM430 dosage of 0.2% based on the weight of the starting rosin, in atmospheres of nitrogen for protection, reaction time for 2h. The decoloration mechanism was analyzed with UV.The hydrogen atom generated by disproportionate catalytic reaction with TM430. The color substances in the raw rosin were reduced to colorless by hydrogen atom generated by catalytic of TM430.
Synthesis of Three-Dimensionally Ordered Macroporous Co/SiO2 Catalysts by Sol-Gel Method
Authors: Junsawat Jittima , Phumthiean Nichakan , Senthongkaew Payoon , Achiwawanich Supakit
Published: March 2013

A preparation of novel cobalt-based catalyst on three-dimensionally ordered macroporous (3DOM) silica supporter using poly (methyl methacrylate) monolith as a template has been studied. Monodispersed PMMA colloids were synthesized via an emulsion polymerization, resulting in PMMA spheres with the diameter of 390-400 nm. Two processes were employed for the 3DOM Co/SiO2catalyst fabrications, a single-stage sol-gel synthesis (SG) and incipient wetness impregnation method (IM) on synthesized 3DOM SiO2. Both catalysts were characterized using X-ray Diffraction (XRD), X-ray Absorption Spectroscopy (XAS), Scanning Electron Microscope (SEM) and specific surface area analysis. The XRD and XAS results showed that the doped Co in the 3DOM Co/SiO2(SG) were the mix phase of Co(NO3)2and Co3O4, while, only Co3O4was found in the 3DOM Co/SiO2(IM). The SEM micrographs revealed that both catalysts feature periodic macroporous structure with mean pore diameter of 300-350 nm. Specific surface area of the 3DOM Co/SiO2(IM) and the 3DOM Co/SiO2(SG) catalysts are 195 m2/g and 286 m2/g, respectively.
Catalytic Synthesis of Ethyl Acetate Using Ti2SnC
Authors: Long Yun Hui , Guo Jun Ming , Huang Du Shu , Liu Gui Yang
Published: March 2013

The catalytic synthesis of ethyl acetate from ethanol and acetic acid using Ti2SnC in liquid phase under the atmospheric pressure was studied. The influences of some factors such as catalyst usage, initial reactant molar ratio, reaction temperature and reaction time on acetic acid conversion rate of this reaction system were investigated. The acetic acid conversion rate of 88.12% is achieved while the molar ratio of alcohol and acid is 1:3.6, the amount of catalyst is 0.2000 g, the reaction temperature is 80 °C and the reaction time is 30min. The catalyst Ti2SnC is the ideal catalyst for synthesis of ethyl acetate for good catalytic performance, non-corrosive to equipment, easily separated from product and used repeatedly.
Study on α-Pinene Isomerization over MCM-41 Supported SO42-⁄TiO2
Authors: Dai Xue Yu , Wu Chun Hua
Published: March 2013

Mesoporous MCM-41 molecular sieve was synthesized hydrothermally and selected tetraethoxysilane as silica source. Solid superacid was supported on MCM-41 by dipping and roasting. The samples were characterized by XRD, TEM, and FT-IR. Solid superacid evenly dispersed on MCM-41 with a good pore structure. Their catalytic activities were evaluated in the isomerization of α-pinene. The results show that samples had a good conversion rate and selectivity.
Inhibition Effect of N-Octyl-2-Pyrrolidonium Chloride on the Corrosion of Mild Steel in Acidic Medium
Authors: Zhuang Zi Chong , Huang Bao Hua , Liu Jun , Lu Yu Jing , Pan Zhan Chang , Zhang Kun
Published: March 2013

A new ionic liquid, N-octyl-2-pyrrolidonium chloride (NOPC), were synthesized and evaluated as inhibitors for mild steel (Q235) corrosion in 1 mol/L HCl. The adsorption behavior and corrosion inhibition mechanism of NOPC for mild steel in HCl solution were investigated by using weight loss measurements, electrochemical techniques, and SEM. The inhibition efficiency increases with the increasing concentration of NOPC in 1 mol/L HCl and decreases as the temperature increases. The results indicate that NOPC is able to function as a mixed type inhibitor.
Adsorption CO2 on Activated Carbon with Surface Modification
Authors: Lin Cheng , Zhang Hui Yun , Lin Xiao Ying , Feng Yun Fei
Published: March 2013

The success of CO2 capture from flue gas with solid sorbent is dependent of a low cost sorbent with high CO2 adsorption capacity and selectivity. Modifying surface texture of activated carbon with impregnating amines is expected to offer the benefits of liquid amines in the typical adsorption process routes. In this work, cocoanut activate carbon (AC) is firstly alkalified by KOH solution, then modified by impregnation of tetraethylenepentamine (TEPA), triethylenetetramine (TATA), and triethanolamine (TEA) to form a new type of sorbents. The effects of alkalifying treatment and temperature on CO2 adsorption capacities of the sorbents are investigated. Results indicate that the activate carbons modified by combining alkalification pretreatment firstly and then impregnated amines at low temperature are profitable for CO2 adsorption. The adsorption capacities of CO2 are enhanced with TEPA and TETA impregnation on the activate carbon pretreated by KOH solution. And CO2 adsorption capacity of new sorbents is stable after many adsorption and desorption cycles.
Discrimination and Simultaneous Determination of 6-BA and KT by Polarized Synchronous Light Scattering and Synchronous Light Scattering Spectrum
Authors: Zhao Xiao Hui , Zhu Qian Hua , Yang Qiong , He Wei , Zhou Shang , Li Xiao Yan , Yang Ji Dong
Published: March 2013

In pH=5.70 B-R buffer solution, Na2WO4 and rhodamine 6G（R6G） could react with natural cytokinins of 6-benzylaminourine (6-BA) and kinetin (KT) and resulted in a great enhacement of synchronous light scattering (SLS) signals. This article first established the degree of polarized synchronous light scattering (P) based on the measurements of the polarized synchronous light scattering signals to distinguish two natural cytokinins of 6-BA and KT. Simultaneously based on the synchronous scattering spectrum and the double standard curve method, a novel method for simultaneous determination of 6-BA and KT was developed by SLS spectralmethod. The method was applied to simultaneous determination of 6-BA and KT in balsam pear skin and tomato skin with satisfactory results.
Study on Coking during the Pyrolysis of Coal to Acetylene in the Plasma
Authors: Tian Yuan Yu , Qiao Ying Yun , Xie Ke Chang
Published: March 2013

The research of all kinds of factors is put up on the inner coking of coal in the plasma reactor during the processing of pyrolysis of coal to acetylene, includ cooking phenomenon, coal of property, coal of grain degree, enter anticipate a speed , power and equip structure. In the arc plasma jet, different kind of coal has different coking character. The aromatics, colloids, asphaltene and carbenes are the precursors of the cokes.The mostly reasons of coking in the plasma reaction equipment are the particle size, the feeding velocity, the power of plasma and the structure of equipment. With the increasing of feeding velocity, the coking of system becomes worse. When the particle size is less than 80~100 mesh, the system will not produce cokes. When the particle size is about 100~120 mesh, the system will begin to produce cokes. When the particle size is larger than 140 mesh, the system will produce a lot of cokes.With the increasing of plasma power, the speed of coking will become smaller.
Non-Thermal Plasma and Catalyst System for Simultaneously Oxidizing SO2 and NOx
Authors: Han Shi Zhong , Zhang Qiang , Chen Zhi Qiong
Published: March 2013

For the requirements of nitric oxide (NOx) and sulfur dioxide (SO2) removal process in coal-fired power plant, a new non-thermal plasma system combined with catalyst was developed to investigate the effect of parameters such as temperature, atmosphere, residence time, and additives (NH3 and methanol) on NOx and SO2 conversion rate. The results indicated that the new system could greatly promote the NOx conversion rate while it only had a slight influence on the SO2 oxidization rate. Meanwhile, high temperature suppressed the NO oxidization, and promoted the SO2 oxidation. The long residence time was beneficial to the NOx and SO2 oxidization. In the absence of water, the additive of NH3 can improve NO, NOx, and SO2 oxidization rate due to the reactions between NH3 and NOx, or SO2. Contrary to NH3, methonal had a negative effect on NOx and SO2 oxidization.
Characterization of Magnetic Cellulose Microspheres Reconstituted from Ionic Liquid
Authors: Peng Shuai , Fan Juan , Chang Jie
Published: March 2013

Magnetic Fe3O4/cellulose microspheres with mean diameter of 100 μm were prepared by sol-gel transition method using ionic liquids (AmimCl) as solvent for cellulose dissolution and regeneration. Their structure , properties and morphology were analysed using scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and vibrating-sample magnetometer. The results indicated that the synthesized microspheres were good sphere with a mean diameter of about 100 μm. It also showed that cellulose had been successfully covered onto the surface of Fe3O4 after the preparation. Therefore, we have provided a simple and biocompatible support for applications in the biomaterials field.
Design, Syntheses and Biological Evaluation of 5-Fluoroindolin-2-One Derivatives with Urea Linkage
Authors: Zou Bao Hua , Fang Zheng , Yang Zhao , Guo Kai
Published: March 2013

Nine 5-fluoroindolin-2-one derivatives with urea linkage were designed and synthesized. The obtained structures were identified by 1H NMR, MS and elemental analysis. In vitro evaluation of antitumor bioactivity was performed by MTT method. Most of synthesized compounds showed antitumor activities, especially, compounds 6e and 6f, which were better than or equal to the antitumor activity of positive control.
Excellent Preparation of Azetidin-3-Ones from Propargylic Alcohols by Gold-Catalysis
Authors: Tan Ping , Xiang Jian Nan
Published: March 2013

Azetidin-3-ones are important heterocycles in organic synthesis and pharmaceutical chemistry. With gold-catalyzed alkyne intermolecular oxidation, these versatile heterocycles can be prepared in three steps from readily available propargylic alcohols with high efficiencies.
Rehabilitation of Corrosion-Damaged Substandard RC Columns Using FRP Sheets
Authors: Kalyoncuoglu Aras , Ghaffari Pooya , Goksu Caglar , Ilki Alper
Published: March 2013

Corrosion is one of the major problems for the existing structures and may cause significant decrease in drift capacity and strength of RC (reinforced concrete) columns due to reduction of effective cross-section of reinforcing bars, alteration of bond characteristics between reinforcing bars and concrete, and cover cracking along the reinforcing bars. Therefore, rehabilitation of corrosion-damaged columns is extremely important, particularly in seismic regions and if a substandard construction methodology is used. In this paper, an experimental work is presented on the seismic performance of rehabilitated/retrofitted substandard RC columns, which were damaged due to corrosion of reinforcing bars. For this purpose, four substandard columns were tested under high axial load and reversed cyclic lateral loads. The columns were constructed with extremely low quality concrete and plain round bars. The spacing and details of transverse reinforcing bars did not comply with the code regulations as well. Then, the specimens, except the reference one, were subjected to accelerated corrosion process. One of the corrosion-damaged specimens was tested before rehabilitation/retrofitting procedure, while the other two specimens were tested after rehabilitation/retrofitting procedure. The test results clearly demonstrated the efficiency of the applied rehabilitation/retrofitting procedure, both in terms of strength and ductility. Furthermore, analytical predictions about strength and failure modes of the specimens are compared with experimental findings.
Seismic Analysis on Masonry Structures Strengthened with Reinforced Concrete Splint
Authors: Kang Yan Bo , Huang Shi Min , Yao Qiu Lai
Published: March 2013

Strengthening the brick walls with reinforced concrete splint is a conventional and effective method of strengthening masonry structures. To the method, the text process and analysis of 6 brick walls strengthened with reinforced concrete splint and the existing calculation analysis method about bearing capacity are introduced in this paper. Through the series of low-cycle repeated load experiments, we study the different performance between unreinforced brick wall and brick wall strengthened with reinforced concrete splint. Based on the analysis, we find the seismic capacity of the brick wall strengthened with reinforced concrete splint such as the bearing capacity and ductility is enhanced clearly. Meanwhile, the calculation parameter in technical specification for seismic strengthening of buildings has good accordance with the experiment results.
Estimation of Overhead Transmission Lines ACSR Combined Elastic Coefficient
Authors: Li Yong Ping , Ni Yang , Huang Zhi Yi , Su Yu Cheng
Published: March 2013

According to the characteristics of the aluminum conductors, coated-steel reinforced (ACSR), combined the feature that isotropic and continuity of the folded yarns, establish the calculated equation of the Poisson ratio of the discrete and anisotropic wires. After given the calculated equation of stiffness of large cross-section wires, we obtained the calculated equation of elastic modulus, shear modulus and Poisson ratio. These wires stiffness not only reflect the characteristics of the composite material, but also provide guidance and reference for the mechanical calculation of the wires and installation of overhead conductor and ground wires and the following equation also has certain value in mechanics calculation and lines of construction.
Remote Hybrid Testing on Bridge System
Authors: Fan Yun Lei , Xiao Yan , Guo Yu Rong , Yuan Tao
Published: March 2013

A networked structural laboratories system for evaluating the seismic performance of large-scale structure systems by seamlessly integrating geographically distributed experimental and computational substructures into a single test is described in this paper. It consists of an independent network based communication platform and various applications. The effectiveness of the proposed system is demonstrated by remote hybrid tests of a six-span bridge system at the Hunan University, Harbin Institute of Technology, Tsinghua University, China and the University of Southern California, USA. Successful application shows the system enables the shared use of testing resources by integrating single structural laboratories into a powerful and networked laboratory with advanced capability.
Discrete Element Method (DEM) Analyses of Hot-Mix Asphalt (HMA) Mixtures Compaction and Internal Structure
Authors: Chen Jing Song , Zeng Lei , Yin Jian
Published: March 2013

Asphalt mixture compaction is an important procedure of asphalt mixture construction and can significantly affect the performance of asphalt pavement. In this paper, an open source DEM code was applied to simulate the compaction of hot-mix asphalt (HMA) with the Superpave gyratory compactor. The asphalt mixture compaction process, air voids distribution, internal coarse aggregate structure, and the effect of CA ratio were investigated from a microscopic point of view. The analysis results show that DEM simulation is an economical and effective approach to the research of asphalt mixture compaction, and has tremendous potential for asphalt mixture design.
Effects of Truck Impacts on Bridge Piers
Authors: Agrawal Anil K. , Liu Guang Yong , Alampalli Sreenivas
Published: March 2013

According to Federal Highway Administration, impact by moving trucks is the 3rd leading cause of bridge failure or collapse in the country. Although current AASHTO LRFD Guide Specifications prescribe designing bridge piers by applying a 400 kips static load at a height of 4ft to improve their impact resistance, recent studies have shown that the dynamic forces because of truck impacts may be significantly higher than that recommended by the AASHTO Guide Specifications. In this paper, we present an extensive investigation on the impact of a three-span steel girder bridge with reinforced concrete piers by trucks running at different speeds through models of bridge and the truck in LS-DYNA, including a correlation between seismic and impact resistance of bridge piers. Results also present a comparison between static load prescribed by AASHTO Guide Specifications and dynamic impacts loads observed during numerical simulations. A performance based approach is proposed to design bridge piers against truck impacts.
Nonlinear Analysis of a New 3D Skip-Floor Staggered Shear Wall Structure
Authors: Liu Jian Xin , Li Pei , Wang Hong Nan , Zhu Mei Chun , Zhang Zhi Hong , Wang Ying , Wang Hong Wei
Published: March 2013

The elastoplastic nonlinear analysis is provided by considering both spatial effect and influence of slab and connecting beam. The seismic internal force distribution is also studied. It shows that compared with the 2D model and traditional 3D coupled shear wall structure, 3D skip-floor staggered shear wall structure has superiority in many respects, such as initial rigidity, uniformity of force, energy dissipation, etc. Therefore, this new structural system has good economic benefits and wide applications.
Thermal Experiment of a Reinforced Approach Pavement for Semi-Integral Abutment Jointless Bridge
Authors: Zhan Xue Fang , Shao Xu Dong , Liu Guo Li
Published: March 2013

Semi-integral abutment fully jointless bridges, which connecting the main girder, the approach slab and the reinforced approach pavement all together and eliminating all the deck expansion joints and also the approach reinforced pavement joint is studied. As we know, the temperature variation is the key influence factor of the basic performance of the fully jointless bridges. When the temperature drops, the cracks appeared along the reinforced approach pavement. In the paper, emphasisis primarily made on simulating the temperature drops. A 28m full scale model stretching experiment simulating the temperature drops has been carried out in laboratory. After the experiment simulation we found that:(1)The crack width of approach pavement distribute uniformly at the pre-cut joints and their crack widths ranged mainly between 0.2mm and 0.8mm and the mean crack width was 0.37mm when the maximum stretch length at the end of the approach slab reached 9.87mm, which was within AASHTO and the Chinese highway pavement specification allowable value; (2)the load transfer capability coefficient at the third pre-cut joint with the maximum crack width (0.97mm) was 84%,which also satisfied the allowance of Chinese highway pavement specification. So this reinforced approach pavement is safe to connect semi-integral abutment bridge for the temperature length of 45m with the maximum temperature decrement of =20 ºС from the average reference construction temperature.
Numerical Simulation and Monitoring Analysis for High-Fill Slope
Authors: Duan Liang Liang , He Guo Jing , Yi Jin , Li Yue Feng
Published: March 2013

It is necessary to simulate construction and operation and analyze monitoring data in time for dynamic construction and reinforcement design of high-fill slope. As a typical example, some high-fill slope is calculated with limit equilibrium method for evaluation of the slope stability. The slope is also calculated with finite element method (FEM) and monitored during construction and operation. FEM stress and displacement results are in good agreement with in-situ monitoring data. Combining FEM computation with monitoring analysis is the main process of dynamic design which guides construction and reinforcement and assures safety.
Wind-Induced Vibration Analysis and Remote Monitoring Test of Wind Turbine Power Tower
Authors: Chen Ai Jun , He Guo Jing
Published: March 2013

The major loss of the hurricane was damage and collapse of structures, In particular, wind power tower wich requires both the use of wind, wind on the structure plays a leading role in the tall slender flexible structure.In this paper, tests of remote sensing dynamic monitoring of tower structure with wind power are carried out, using measurement techniques of high-frequency and high-speed electromagnetic interference.
Progressive Collapse Research: Current State and Future Needs
Authors: El-Tawil Sherif , Li Hong Hao
Published: March 2013

Research on progressive collapse has advanced greatly in the past forty years. Motivated by heightened research interest around the globe stemming from recent high profile events, the rate of progress has been especially rapid in the past decade. Research in this area has been primarily enabled by massive improvements in computational simulation tools and hardware as well as structural testing at a scale and level of sophistication never seen before. While the research effort shows no signs of slowing down, several agencies have already undertaken large codification efforts in an attempt to synthesize the rapidly growing knowledge base into practical and meaningful guidelines for collapse-resistant design. This keynote paper presents the state-of-the-art in progressive collapse research. The paper sheds light on several topics including: methods for assessment of structural robustness; methodologies for enhancement of system collapse resistance; probabilistic models for progressive collapse risk assessment; and current trends and research needs, which discusses current gaps in our understanding of progressive collapse research and identifies research efforts needed to address them.
Thermal Deformation of Cement-Asphalt Mortar under Repetitive Heating and Cooling
Authors: Zhou Xi Ling , Xie You Jun , Zheng Ke Ren , Zhang Sheng , Cai Feng Liang
Published: March 2013

Cement-asphalt mortar interlayer plays an important role in ballast-less track in high speed railway. Cement-asphalt mortar undergoes repetitive changes in temperature when it is exposed to its service environment. Change in temperature has a significant effect on the thermal deformation of cement-asphalt mortar, and even affects directly the durability of ballast-less track. In the paper, length and mass of the specimens of cement-asphalt mortar were continuously measured during the heating and cooling cycles within the range of temperatures of -10~60°C. The results indicate that there is an evidently irreversible shrinkage at the end of the first cycle of heating and cooling. The shrinkage taken place at the end of cycles of heating and cooling decreases with the increase in cycle numbers. Apart from the curve for the first heating, deformation curves of cement-asphalt mortar either for heating or for cooling are nearly lines. After being heated and cooled for 5 times, the temperature-deformation curve for heating nearly overlaps the curve for cooling. The percent of moisture loss at the end of every cycle decreases with the increase in cycle numbers. Thermal shrinkage occurs at about 0°C in the first heating.
Experimental Research on the Mechanical Property of Hybrid Fiber Reinforced Ferrocement
Authors: Chen Sheng Ping , Tian Gang
Published: March 2013

The tensile and bending behaviour of steel-polypropylene hybrid fiber reinforced ferrocement were investigated in this paper through direct tensile test and four-point bending test. Different volume fractions of steel fiber, polypropylene fiber and steel wire mesh were considered. A total of 42 tensile and bending specimens were tested. Experimental results showed that, compared to plain ferrocement, the cracking tensile strength and the ultimate tensile strength of steel-polypropylene hybrid fiber reinforced ferrocement with 0.5% volume fractions of steel fiber and 1.0% volume fractions of polypropylene fiber increased by 9% and 15% , and the cracking moment and the ultimate moment also increased by 29% and 52%. It can be concluded that this mix ratio had best effect on the mechanical property of ferrocement.
Research on Self-Compacting Concrete Made with Recycled Aggregate
Authors: Zhou Ai Guo , Yin Jian , Song Wei Min , Chi Yi
Published: March 2013

It is studied the effect of binder quantity, water binder ratio on properties of self-compacting concrete made with recycled coarse aggregates. It can be prepared C50 self-compacting concrete made with recycled coarse aggregate by adjusting send proportion, binder quantity, and mixing mineral additive. For example, when the binder quantity is 600 kg/m3, water binder ratio is 0.28, the flexural strength and compressive strength at 28 days of self-compacting concrete made with recycled coarse aggregates are 9.07 MPa and 68.47 MPa respectively.
Study on the Performance and Application of High Performance Pavement Portland Cement Concrete
Authors: Liu Ai Ping , Yin Jian , Song Wei Min
Published: March 2013

Because of some drawbacks including low strength, poor dimensional stability, low abrasion resistance, easy to crack and other shortcomings, Portland cement concrete was limited to use as a dominant pavement material in highway construction. This paper studied the feasibility of making high performance pavement concrete by adding 20-40% of high-quality composite ultra-fine fly ash (CUFA) technology to achieve high-performance of concrete roads have been studied. The test results indicated that: with cementitious material content of 360~400 kg/m3 and CUFA content of 20% ~ 40%, adding CUFA improved the workability of concrete significantly; in the meantime, the 28d compressive strength was as high as 50 MPa, and the later strength of concrete continued growing. The designed concrete satisfied the requirements of opening to traffic after 3 days after the construction and heavy and extra heavy traffic in 28 days. The durability, especially the abrasion resistance, and the crack-resistance were improved significantly. The designed pavement concrete not only had a good compressive performance for practical engineering but also had good technical, economic, social and environmental benefits.
Performance Evaluation of Existing Bridges under Vehicle Dynamic Effects
Authors: Cai Chun Sheng , Zhang Wei , Deng Lu , Xia Miao
Published: March 2013

This paper summarizes the recent work by the first author’s research group related to the performance evaluation of existing bridges under vehicle dynamic effects. Based on the data from short-term monitoring of existing bridges, a framework to estimate the extreme structure responses from the live load in a mean recurrence interval is developed in the first part. The Gumbel distribution of the extreme values was derived from an extreme value theory and Monte Carlo Simulation. In the second part, a framework of fatigue damage and reliability assessment for existing bridges is presented to include the effects of the progressively deteriorated road conditions and random dynamic vehicle loads in bridge’s life cycle. The random effects of vehicle speed and type, road profiles, and stress ranges are included. Studies have shown that the vehicle-induced dynamic allowance IM value prescribed by the AASHTO LRFD code may be underestimated under poor road surface conditions (RSCs) of some existing bridges. In addition, multiple dynamic stress ranges induced by vehicles cannot be included in the maximum displacement-based dynamic allowance IM values. In the third part of this paper, the reliability indices of a selected group of prestressed concrete girder bridges are calculated by modeling the IM explicitly as a random variable for different RSCs. Nevertheless, a reliability based dynamic amplification factor on stress ranges (DAFS) for fatigue design is proposed to include the fatigue damages from multiple stress range cycles due to each vehicle passage at varied vehicle speeds under various road conditions in the bridge’s life cycle.
Experimental Investigation of the Wind Pressure Distribution and Wind Interference Effects on a Typical Tall Building
Authors: Li Yi , Li Q.S. , Ju K.L
Published: March 2013

Most tall buildings are constructed in the prosperous center of large cities, where is inevitable to be surrounded by many interfering buildings. Wind interference effects among buildings should not be neglected. Therefore, it is necessary to investigate wind interference effects on such tall buildings. Based on the wind tunnel test of rigid model of a tall building, the wind pressure distribution on the building with interfering buildings around it has been researched, the contours of the mean and fluctuate wind pressure coefficients have also been presented. It has been found that shielding effect and channeling effect are significant in the wind interference effects on building. Wind pressure coefficients on side wall and leeward wall of a upstream building may be dramatically changed in case the wake boundary of the upstream building is interfered. The conclusions might be used as reference to structural design and plan.
Numerical Analysis of Mechanical Properties of Precast Segmental Concrete Test Beam with External Tendons
Authors: Jiang Hai Bo , Deng Yan Song , Qiu Yun , Wei Chun Gen , Chen Li , Feng Wen Xian
Published: March 2013

A finite element model is proposed for numerical analysis of mechanical properties of precast segmental concrete test beam with external tendons. The 3D finite element model of test beam is established by SOLID65 element in ANSYS software, while the dry joint between segments is simulated by contact element, and the attachment between concrete beam and external prestressed tendons is achieved by node coupling method. Numerical simulation analysis reveals structural behavior, stress variations and crack opening cases of joints of the test beam by considering the concrete material and geometric nonlinearity. Influencing factors of the bending mechanical properties of the test beam are researched with different tendon types, secondary effect of external tendons and external tendon slip at deviation. Results of the numerical analysis reveal that the segmental joints are in the compressive state below the 300kN.Crack opening is the key factor of the mechanical properties of the test beam above the 300kN.The results can be used for structural design of precast segmental bridge.
Spatial Analysis of Bridges Composed of Arches and Trusses by Truss Section Finite Element Method
Authors: Yang Shi Ruo , Chen Dan Qing
Published: March 2013

In this paper, the stiffness and load matrix of Jiujiang Changjiang River Bridge are established by truss section finite element method. The basic assumptions and calculating process is proposed, and the functions of bridge frames are also investigated. Finally, the lateral displacement is calculated under the action of wind load (or both wind and train load).
A Soft-Roadbed Settlement Prediction Model Based on RBFNN
Authors: Peng Xiang Hua , Wang Zhi Cha , Yu Min
Published: March 2013

The control of subgrade settlement has been the main influencing factor on highroad pavement quality, so estimating settlement amount after construction based on designed embankment height and planning the construction filling height beforehand through the settlement prediction is a very important work. Because of the complex coupling properties and high nonlinear characteristics of the factors influencing foundation settlement, a soft-roadbed settlement prediction model based on RBFNN (Radial Basis Function Neural Network) is proposed, combining the global fitting properties of RBFNN. The analysis shows that the model owns good fitting property and high prediction precise, and certain practical value.
Failure Mechanism of a Slope Anti-Sliding Pile
Authors: Chen Lin , Yao Yong , Yang Jiong , Zhang Zhao Qiang
Published: March 2013

According to finite element strength reduction method，the article has discussed the failure mechanism of anti-sliding pile by using finite element software MIDAS /GTS ，exploration report and anti-sliding pile design data.The comparative analysis shows that the failure of anti-siding pile is contributed by the slope excavation and rainwater.The analysis method and results can provide reference significance to other anti-sliding pile design.This paper also provide a feasible method for prediction of consequence in slope excavation.
Study of the Effect of Shear Rates on Residual Shear of Landslide Soil
Authors: Chen Chuan Sheng , Liu Jing Fang , Wen Shi Zhi
Published: March 2013

The residual strength is one of the most important strength parameters to evaluate the stability of a reactivated landslide slope, but the relation between residual strength gained by using ring shear tests and shear speed still remains unclear. In order to clarify the relationship between them, the variation in residual friction coefficient of slip surface soils with shearing rates were calculated and discussed in this paper by means of an undrained ring shear apparatus on Miaowan sample of China-Loess Plateau , predominantly consists of silty-sandy(81.3%), and Kamenose sample of Japan, predominantly consists of clay(73.2%) in texture .The residual friction coefficient was observed to be lower for higher shear rates in Kamenose sample;while the variation of its shear behaviour at different shear rates is fluctuant in Miaowan sample. This change in pore water pressures and soil texture could be thought as the rate effect mechanism of residual shear strength.
Foundation Pit Dewatering and Ground Subsidence in Binary Structural Stratum of Wuhan
Authors: Li Ying , He Zhong Ze , Yan Gui Hua , Han Feng You
Published: March 2013

The geological model of pit of binary structure stratum is established under the analysis of the engineering geological characteristics of the binary structure stratum of Wuhan , combined with land subsidence and groundwater flow characteristics calculated. Associated with the use of software of Processing Modflow to calculate settlement around the excavation, the rules of ground settlement of excavation of dual structure stratum in Wuhan are obtained. And it provides a theoretical foundation and practical support for the same project.
Pile Bearing Properties Analysis Based on Energy Method
Authors: Liu Si Si , Xie Zhong Qiu
Published: March 2013

Energy transfer of pile body in foundation is considered by the energy balance equation of pile unit. Bilinear model is used to calculate the pile side load transfer, and trilinear model to calculate the toe resistance load transfer. According to the deformation coordinating relations, pile load-settlement curve analysis method is obtained. Comparing the in-situ and calculation data, the results show that they are basically consistent. The conclusions are pile bearing properties can be analyzed reasonably by this method, and the calculation results can provide a reference to engineering practice.
Self-Centering Buckling-Restrained Braces
Authors: Liu Lu , Wu Bin
Published: March 2013

Buckling-Restrained Brace (BRB) consists of energy dissipative core and a strengthening tube to prevent buckling when subjected to compression. Under cyclic loading, BRB exhibits elastoplastic hysteretic behavior, which leads to certain amount of permanent displacement in the structure after medium to severe earthquake. Residual deformations can result in increased cost of repairing. An innovative BRB device called Self-centering Buckling-Restrained Braces (SC-BRB) is devised to control maximum and residual drift of steel moment frame buildings subjected earthquakes. The SC-BRB is composed of the BRB energy dissipating cores which are responsible for energy dissipation, and the self-centering system which makes BRB energy dissipating core return to its initial position upon completely unloading. By exploring the mechanism of SC-BRB, it is found that to ensure fully self-centering capacity, the self-centering bar should have sufficient elongation capacity as well as considerably large elastic modulus which could afford stiffness in real structures
Numerical Simulation Analysis on Seismic Behavior of a New Type Prefabricated Slab
Authors: Hu Qi Gao , Cui Wei Feng , Gao Jing Wei , Yin Jiang
Published: March 2013

In previous earthquakes, masonry structures, especially those masonry structures with prefabricated slab was damaged severely, and caused heavy casualty and property losses. In order to improve the seismic behavior of prefabricated slab, a new type of prefabricated slab with longitudinal and transverse joint steel bar was designed. By employing a numerical simulation procedure, LS-DYNY3D, models were established, and their seismic behaviors were analyzed .The results show that, the masonry structure of new type prefabricated slab with longitudinal and transverse joint steel bar is better than the structure with traditional prefabricated slab in structural integrity and stability. That is to say, its seismic behavior is better than the masonry structure with traditional prefabricated slab.
Risk Analysis of High-Rise Reinforced Concrete Frame-Shear Wall Structure in Progressive Collapse
Authors: Yu Li Dong , Li Hong
Published: March 2013

The purpose of the this study was to find the influence of local members of high-rise reinforced concrete frame-shear wall structure failed in different position.Referred to the basic requirements against progressive collapse provided by JGJ03-2010,Based on alternate path method ,This paper presents an analysis procedure that made Linear static analysis to a modal of 24-storey frame-shear wall structure designed according to the current code with SAP2000.The results show that once the edge column failed ,the structure will collapse.However,the corner shear wall constitute little threat to the progressive collapse.After the local members failed ,the lower part of the building contribute to the load path and it can results in axial force ruleless in beams,which make against to load bearing if they are tensile forces.The concentrated tensile stress appears around the continuous beam,and it is possible to be broken early after local member failed if close to the failed shear wall.
Experimental Analysis on PV/T-SAHP Performance under the Influence of the Electronic Expansion Valve
Authors: Wang Hai Tao
Published: March 2013

Under different Electronic Expansion Valve (EXV)opening degree at the fixing frequency of 50hz of the compressor，we had test the system performance. When the cooling refrigerant influence to the PV module and the heating air influence to the collector／evaporator reached the balance，the photoelectric efficiency achieved the maximum．When the EXV opening degree fixing, with the raising of the solar radiation, the compressor power values appeared oscillation，and the oscillation was especially evident when the EXV at the maximum opening degree． So we put forward the PV/T-SAHP system stability principle．At the same time，we found that the key of the PV／T-SAHP research is to discover the relation between the solar radiation and the superheat of collector／evaporator．
The Developing of High Efficiency Coal-Fired Flue Gas CO2 Capturing Absorbent
Authors: Yang Xiang Ping , Jiang Yu Ze , Lu Shi Jian , Jiang Di Wen
Published: March 2013

For developing the high efficiency and new-style CO2 absorbent, the CO2 absorbing ability, separating performance, causticity to steel and decomposition performance were studied and contrasted for various kinds of absorbent. It was suggested that 12%MEA+7.5%AMP is the best composite absorbent. The rich liquid regeneration temperature is 100°C. Adding 1% sodium metavanadate could reduce the corrosion and decomposition.
Study on Catalytic Wet Oxidation of H-Acid Containing Water over Fe/SiO2 Catalyst
Authors: Li Hong Ya , Zhao Bin Xia , Bai Wei Li , Zhang Xiao Li
Published: March 2013

This study has investigated the degradation of H-acid (1-amino-8-naphthol-3, 6-disulfonic acid) containing water by catalytic wet hydrogen peroxide oxidation method, in which the catalyst of Fe/SiO2 was prepared by impregnation technology. The effect of catalyst dosage, initial pH value, amount of hydrogen peroxide and reaction temperature on the degradation process have been discussed, and the results indicated that wet hydrogen peroxide oxidation is an effective method for treating the wastewater containing H-acid, under the conditions that: catalyst dosage was 2 g, initial pH value was 7, amount of hydrogen peroxide was 10 mL (0.83 time of theoretical required amount) and reaction temperature was 80 °C, the COD and color removal rate can reach 87.3% and 96.5%, respectively.
A New Kind of FDM/FEM Squeeze Casting Temperature Field Calculation Model
Authors: Zhao Yu Hong , Yang Wei Ming , Hou Hua
Published: March 2013

A new FDM/ FEM model is developed to simulate the temperature field during the solidification process of squeeze casting. So we can transform the FDM mesh into FEM mesh directly ,then established the relationship of pressure change and melting temperature change and correct the size of melting temperature value and other thermal physical parameters (such as the thermal conductivity)which is related to the temperature ,and establish the temperature and thermal physical parameter relationship to get a data base. The solidification process of AM50A magnesium alloy is simulated. Squeeze casting experiments are also incited for validating the new FDM/FEM model. It is shown that the results of numerical simulation are in agreement with the experimental results.
A New Numerical Simulation Model for Shrinkage Defect during Squeeze Casting Solidification Process
Authors: Hou Hua , Ge Hong Hao , Zhao Yu Hong , Yang Wei Ming
Published: March 2013

In this paper, according to the characteristics of squeeze casting solidification process, the calculation model (FDM format) of the partial differential equations with high thermal conductivity is used to the numerical simulation of temperature field. Dynamic isolated multi-molten pool judgment method is used to determine the position of the pool and FEM is used to calculate the pressure of pool center. If the pressure of molten pool center has been down to 0, the liquid metal closed in the scale will be solidification under the condition of no pressure, and will shrinkage based on the way of gravity shrinkage. The equivalent liquid surface descending method of isolated molten pool is used to predict the formation of shrinkage defect; the simulation result is coinciding with experimental data.