bluuebunny/crossref_metadata_2025 huggingface dataset:
Damage Detection of Steel Domes Subjected to Earthquakes by Using Wavelet Transform
Authors: Zheng Jin , Chen Bo , Ye Chun Yang
Published: November 2010

The degradation of a steel dome due to strong earthquake may lead to a sudden loss of structural stiffness in a structure and cause a discontinuity in acceleration response time histories recorded in the vicinity of damage location at damage time instant. A damage detection approach based on discrete wavelet transform is developed and implemented in this paper to detect the damage time instant and location of a steel dome due to sudden seismic damage. To examine the feasibility of the wavelet-based detection approach, parameter studies are carried out to investigate the detection quality for different noise intensities. The time instant and location of sudden damage event are detected through the distribution of discrete wavelet coefficients in the time domain and spatial distribution along the structural span.
Tunable Multimode Filtering of Solid Acoustic Waves in a Three-Component Phononic Crystal Slab
Authors: Li Jing
Published: November 2010

Using of the multiple scattering methods, we characterize the positive and negative multi-refraction and transmission properties of a solid-based phononic crystal composed of coated solid inclusions in view of its applications in tunable multimode filtering. The geometrical parameters are chosen so that a left-handed longitudinal wave mode and a right-handed transverse wave mode, are simultaneously obtained in this three-component phononic crystal. When multimode Gaussian beams are placed transmitting through the phononic crystal slab, both positive and negative refractions are observed. We then study the individual propagation behavior of different modes. The angle dependent transmission beams with different energy distributions are found at the other side of the slab. Transmitted transverse waves coming from different directions incidence finally walk together into four oriented beams. Meanwhile, longitudinal wave incidence with different directions behaves simply as negative refraction in the slab. A far-field longitudinal wave image can be achieved being excited by a longitudinal wave point source. The three-component phononic crystal slab thus can be served as an alternate in tunable multimode filtering devices.
Effect of Binary Admixture of Fly Ash and Slag on the Carbonation of Concrete for Hydraulic Structure
Authors: Li Xue Ying , Zhang Dong Qing , Wang Chen , Zhang Shou Jie
Published: November 2010

Carbonation of concrete for hydraulic structure containing mineral admixtures is studied. It is observed that the fly ash is not benefit to the carbonation resistance, and the different content of fly ash in concrete may play a different role without activator. However, concrete for hydraulic structure using binary admixture of fly ash and slag will make up the defects and when the fly ash to slag ratio is 1:1, the depth of carbonation decreases comparing to concrete using fly ash.
In Situ Preparation of Magnetic P(AOS-St-BA)-Coated CoFe2O4 Composite Microspheres in Soapless Emulsion
Authors: Liu Wei , Zhou Chun Hua , Xu Guang Qiang , Feng Ying
Published: November 2010

Sodium 2-olefinsulfonate (AOS) is used as reactive surfactant to prepare 10 nm around magnetic CoFe2O4 nanoparticles in advance. Magnetic P(St-BA-AOS)-coated CoFe2O4 composite nanoparticles has been synthesized in situ soapless emulsion. The effects of the amount of the initiator, monomer concentration and polymerizing temperature on the convention of monomer are investigated. So the polymerizing conditions are KPS=4.010-3mol/l St=0.75mol/l, mMP=20g/l, T=75 BA=0.15mol/l t=6.0h [AOS]=2% without any surfactant in the latex system. Results of IR and TEM analysis demonstrate that the desired polymer chains has been covalently bonded to the surface of CoFe2O4 nanoparticles, and confirmed that the composite particles have the core-shell structure. Copolymer P(St-BA-AOS) has a good hydrophile ability with functional groups such as -SO3Na and -COO- groups. The saturated magnetization of CoFe2O4/ P(St-BA-AOS) composite could reach 2.10emu/g, and show the characteristics of super-paramagnetism.
Abrasion-Resistance at High Temperature of HVOF-Sprayed WC-12Co Coating on H13
Authors: Lan Jian , Zhang Bing , Hua Lin
Published: November 2010

Co-based WC powder and self-fluxing alloy powder Ni60A were sprayed on hot work die steel H13 substrate via high velocity oxygen fuel (HVOF) spray processing, and microstructure and mechanical properties of two types of coatings were investigated. For WC-12Co coating, some pores were observed, while microcracks were only observed in Ni60A coating, which leads to the lower microhardness and abrasion-resistance at either room temperature or high temperature. At the junction of H13 substrate and WC-12Co coating, metallurgical combination was observed. Under the test condition of load 250g and rotating speed 448r/min, the average friction coefficients obtained at 10 are 0.33 and 0.35 respectively; when the test temperature was 500 , the value of two types of coatings increase to 0.56 and 0.63 respectively. Compared with Ni60A coating, The WC-12Co coating had an excellent abrasion-resistance at high temperature; the weight loss was only one-fifth of the Ni60A coating.
P. aeruginosa Inactivation with Silver and Nickel Doped TiO2 Film Coat on Glass Fiber Riving
Authors: Ubonchonlakate Kornkanok , Sikong Lek , Tontai Tienchai , Saito Fumio
Published: November 2010

The photocatalytic Ag and Ni doped TiO2 films were prepared by sol-gel method and coated on glass fiber roving. The films were calcined at 500 °C for 1 hour with a heating rate of 10°C/min. The surface morphology and properties of synthesized TiO2 films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR) and UV-vis diffuse reflectance spectroscopy (DRS). The results show that TiO2-1Ag and TiO2-1Ag-1Ni films give rapidly kill P.aeruginosa bacteria under UV irradiation and TiO2-1Ni films give well kill P.aeruginosa bacteria under visible light.
The Thin Sheet Metal Rubber Pad Stamping for PEM Fuel Cell
Authors: Lan Jian , Liu Yu , Wei Xi , Hua Lin
Published: November 2010

Bipolar plate is the key component of proton exchange membrane (PEM) fuel cell and represents a significant part of the overall cost and the total weight in a fuel cell stack. The thin sheet metal, with usually 0.1~0.3mm thickness, deformed to bipolar plate with flow channel 0.5~2mm width and depth, by rubber pad stamping can reduce the cost greatly. The rubber pad is simulated by solid element and hydraulic pressure respectively. Experiment shows that the hydraulic pressure can simulate the rubber pad. The thin sheet metal is modeled by solid element and shell element respectively. Considering thin sheet metal material size effect, the shell element cannot simulate the thin sheet metal stamping process because of small corner radius. Modeling rubber pad by hydraulic pressure and thin sheet metal by solid element, the simulation of the rubber pad stamping process shows that 1) the sheet metal in channel appears large uneven strain with high stress; 2) convex fillet make the sheet metal two direction tensions and should keep large fillet corner. Those simulations are validated by experiments. The research on rubber pad stamping will improve the understanding of this micro forming process and provide design guide of flow channel.
First-Principles Calculations of Transition Metal Nitrides TiN and NbN
Authors: Xue F.Y. , Wang H.Y. , Zhao Nai Hui , Li De Jun
Published: November 2010

First-principles study of elastic modulus, shear modulus and some other elastic parameters of TiN and NbN are reported using the plane-wave pseudopotential density functional theory method in this paper. The calculated lattice and elastic constants are in good agreement with the experimental data and other theoretical results. The band structure and density of states of these two compounds were obtained, which show that the mainly contribution on pseudopotential calculations of the density of states of TiN is Ti-3d orbital and N-2p orbital, while TiN is the Nb-4d orbit and B-2p orbit, TiN with higher conductivity; Pugh empirical criterion shows that TiN and NbN are both brittle compounds, and NbN is more brittle than TiN.
Hydration Mechanism and Performances of Tri–Cementitous Materials System Compounded with Clinker Limestone Powder and Fly Ash
Authors: Hou Yun Fen , Huang Tian Yong , Song Shao Min
Published: November 2010

Hydration mechanism and performance of tri-cementitious material, which contains clinker, limestone powder and fly ash, are studied. It is showed that when mixed materials ratio increases from 20% to 40%, the water amount for standard consistency will increase remarkably, and when dosage of limestone powder is 50% in mixed material, the water amount for standard consistency will reach minimum, i.e. 26%; but when limestone powder ratio reaches 40%, the fluidity of slurry reaches maximum, and then it drops with increasing of limestone powder ratio. It is also found that increasing of dosages of mixed materials will decrease flexural strength and compressive strength, and increasing of ratio of limestone powders can result in decreasing of compressive strength at 28 days curing time, especially when ratio of mixed material is 20%. In order to explain the rules that above-mentioned, the particles size distribution is studied, and the hydration mechanism is analyzed.
Mechanical Property of Phosphoaluminate Cement
Authors: Liu Peng , Yu Zhi Wu , Chen Ling Kun , Ding Zhu
Published: November 2010

The influence of curing time on the mechanical property of the phosphoaluminate cement (PAC) was investigated, and the mechanism was discussed as well. The phase composition and morphology of hydration products, electrical properties, porosity and pore size distribution of PAC cured different age were analyzed with XRD, EIS and MIP. The results showed PAC has the property of early-high strength, and the compressive strength of PAC cured for 1 day was about 70% of 28 days’. The main hydration products of PAC are micro-crystal phase and gel of phosphate and phosphoaluminate which formed compacter microstructure. In addition, there are no calcium hydroxide (CH) and ettringite (AFt) produced during the process of hydration. The compressive strength of PAC increased with age, which was due to more products continuously produced. The ac resistance analysis manifested as the change of the nyquist pattern and resistance value.
Preparation of Cation Exchange Fiber by Preradiation-Induced Grafting of Acrylic Acid without Removal of the Inhibitor
Authors: Wei Jun Fu , Zhao Kong Yin , Zhang Huan , Wang Xiao Lei , Chen Li
Published: November 2010

A weak acid cation exchange fiber was prepared by γ-ray pre-radiation induced grafting of acrylic acid (AA) onto polypropylene (PP) non-woven without removal of the polymerization inhibitor in acrylic acid. The factors influenced the grafting degree were discussed, such as radiation dose, initiator concentration, monomer concentration, storage time and bath ratio. It is found that the initiator 2, 2'-Azobisisobutyronitrile (AIBN) was necessary for the increased grafting of AA without removing the inhibitor in AA.
Combinations of Various Self-Consolidating Concrete Test Methods and Workability Responses
Authors: Long Wu Jian , Khayat Kamal Henri , Xing Feng
Published: November 2010

Key workability characteristics of SCC can be described in terms of filling ability, passing ability, and resistance to segregation. These properties are typically characterized by data that relate to specific testing methods. In general, these methods include the components required for evaluating simultaneously filling ability, passing ability, and resistance to segregation, since these properties are rather interrelated. In this investigation, 33 SCC mixtures made with various mixture proportioning parameters, including maximum size and type of aggregate, type and content of binder, and w/cm were evaluated. Comparisons and correlations among various test results used in evaluating the workability responses obtained for these mixtures are established. This is done to highlight advantages and limitations of the various test methods that can be used to assess workability of SCC designated for precast, prestressed applications. Ranges of acceptance of the various test methods are also established.
Analysis of the Mineral Components and Strengths of the Cementuous Materials Produced with Iron Tailings
Authors: Liu Wen Yong , Zhang Chang Hai , Xu Xiao Liang , Zhang Yong , Yan Shu Ai
Published: November 2010

This essay is the subject of national eleventh five support schemes(Number:2008BAB32B14). Applied with testing method, this essay makes a breakthrough in the high-value utilization of iron tailings. According to the tests datas, the cementuous materials acquired from the designed test proved to be qualified for pratical projects. According to the GB/175-2007, the cementuous material sample with 6% iron tailings has got the strenghth that is equal to 52.5# Portland cement; and the cementuous material sample with 10% iron tailings has got the strenghth that is equal to 42.5R Portland cement.
Finite Element Simulation of Tensile Behaviors in the Elastic Region for PP/Nano-TiO2 Composites
Authors: Wu Yu Jiao , Gao Ming Rui , Chen Yu Ling , Li Juan , Ju Shao Lin
Published: November 2010

Polypropylene(PP)/nano-TiO2 composites were prepared by the melt intercalation molding. Based on the assumption of continuum mechanics model for materials, a finite element analysis model for the composites was constructed using ANSYS 11.0 software. In the stage of deformation (pre-yield regime) the response mechanism of the stress and the strain for composites was investigated, and the von mises stress field of PP/nano-TiO2 composites has also been simulated. It was found that the simulation results are Consistent with the testing results at low volume strain level. The results simulated using the 2D model are accurate with the experimental results. If the volume fraction of particles is less, other particles have little influence on the local stress field of a certain particle, no obvious overlap or cross of the stress field could be found between two neighboring particles. While applying different loads, the stress jumps to maximum stress value in the interaction region of the two phase firstly, and then it occurs that the particles debond with the matrix.
Structure and Mechanical Properties of (Cu, Ti) - Binary Metal Doped Diamond-Like Carbon Films
Authors: Jiang Xiao Hong , Zhou Bing , Piliptsou D.G. , Rogachev Aliaksandr V.
Published: November 2010

The composite DLC films doped with different content of Cu, Ti unitary and binary metal have been deposited on stainless steel and silicon substrate using DC-magnetic separation and pulse cathode double-excitation source plasma arc deposition technique. Structural and mechanical properties of the films were investigated by Raman spectroscopy, Atomic Force Microscope, micro-sclerometer and surface profilometer. The results indicated that the hardness and internal stress of Cu-DLC films decrease upon incremental content of copper from 0 to15 at.%. More attractively, a simultaneous improvement of the hardness (31GPa) as well as the release of the internal stress (up to 55%) can be achievable for samples with the relative atomic percentages of Ti and Cu contents of 43.6% and 1.56% respectively.
Aging Effects on Pavement Performance of Asphalt Mortar
Authors: Wang Wen Qiang , Mo Yi Kui , He Hua Yan , Zeng Hua Yan
Published: November 2010

In this paper, asphalt and asphalt mortar are aged in different periods of time by pressure aging vessel (PAV). Systematic tests are made on aged asphalt and asphalt mortar of different aging levels to gain performance indexes such as dynamic shear modulus, phase angle, bending creep stiffness under low temperature, bending creep rate under low temperature, direct tension tensile strength and direct tension failure strain. These indexes are then used to analyze the relationship and regularity between asphalt mortar’ test indexes and high temperature stability, fatigue resistance and anti-cracking performance under low temperature. The test results show that asphalt mortar’ high temperature stability is strengthened as the aging time is prolonged, that the asphalt mortar’ fatigue resistance is reduced when the temperature drops, and that anti-cracking performance under low temperature is weakened when the aging time is extended. In addition, cracking under low temperature was more liable to occur when fine ores are added. As the brittle point tends to increase when the temperature gets lower, cracking is more likely to occur on the asphalt mortar.
Study and Preparation of Ti-Doped ZnO Thin Films by Using Chemical Bath Deposition
Authors: Hsu Cheng Hsing , Yan Shu Fong , Lai Chun Hung
Published: November 2010

Effect of thermal treatments on the structural and electrical properties of the chemical bath deposition derived Ti-doped ZnO thin films are studied. XRD results show that the annealed Ti-doped ZnO films with wurtzite structure are randomly oriented. Crystallite structure, carrier concentration, resistivity and mobility are found to be dependent on the treatment temperature. At a treatment temperature of 100°C, the Ti-doped ZnO film possesses a carrier concentration of 1.3×1020 cm-3, a resistivity of 3×10-3 Ω-cm, and a mobility of 15 cm2/Vs.
A New Regeneration and Restoration Technology of Asphalt Pavement
Authors: Lu Zhao Feng , Qin Min , Guo Xiao Hong
Published: November 2010

In order to defer early damages of asphalt pavement, a new regeneration and restoration technology of asphalt pavement surface is presented in preventive maintenance. The regeneration mechanism and the restoration mechanism were analyzed and the applicable conditions of the technology were proposed. Based on the application of tested road, the relevant construction technology and requirements were put forward. The results show that the new regeneration and restoration technology can better restore the surface performances of original asphalt pavement and prolong the service life of asphalt pavement；in contrast with the traditional preventive maintenance technology, it has a good economic benefit, which is worthy of making more widespread popularization and application in preventive maintenance of asphalt pavement.
Enhancing the Built Environment by Green Roofs
Authors: Du Jin Sheng , Ng Pui Lam , Chen Jia Jian , Fung Wilson Wai Sin
Published: November 2010

Green roof systems are living vegetation integrated on top of roofs. They could enhance the built environment in a number of ways. Herein, different types of green roof and their structural arrangement and materials design are introduced. Various benefits offered by green roof to the urban habitat are discussed. Finally, examples of applications of green roofs are presented.
Effect of Electric Pulse Modification on Alloy Layer of Hot Galvanizing Coatings
Authors: Sun Wei , Wang Jing Song , Cao Li Jun , Sun Hao Yan , Wang Jing Hua , Xue Qing Guo
Published: November 2010

The effect of different electric pulse parameters which include capacitance, voltage, frequency and treating time on the hot galvanizing coatings was studied through orthogonal test of array L25. For each factor, five levels were chosen to cover the experimental region. Results showed that the thicknesses of ally layer with different parameter were all reduced. It is from 63.57μm to 28.49μm. The intuition analysis of orthogonal test derived that the pulse capacitance had the most significant influence on the growth of alloy layer, and the influence of other factors was little. The optimum parameter combination were the capacitance of 200μF , the voltage of 700V, the pulse frequency of 4 Hz, and the treating time of 30 s.
Preliminary Research on Pb-Sn-Al Laminated Composite Electrode Materials Applied to Zinc Electrodeposition
Authors: Ma Hui Yu , Zhu Pei Xian , Zhou Sheng Gang , Xu Jian , Huang Wen Fang , Yang Hong Mei , Guo Jia Xin , Chen Mao Jing
Published: November 2010

Pb-Sn-Al (PSA) laminated composite electrode materials were prepared by means of vacuum hot pressing (VHP), through introducing a medium Sn for solving the immiscibility of Pb and Al. Compared to traditional Pb-(1.0%)Ag alloy electrode, zinc eletrodeposition experiments showed that the cell voltage was reduced by at least 120 mv, the polarization potential of electrode was decreased by 13.2%, the current efficiency was higher 1.3% and the surface morphology of cathode zinc was better and smoother as well as zinc crystals smaller and more dense, while the experiment of the resistance test also showed that the resistance was reduced by at least 50%, therefore, Pb-Sn-Al (PSA) laminated composite electrode materials have lower cell voltage, as well as excellent conductivity, which would have good prospect in development and application in zinc hydrometallurgical industry in the future.
Preparation and Basic Mechanical Properties of Self-Compacting Concrete
Authors: Xie Heng Yan , Zheng Xin
Published: November 2010

Self- compacting concrete (SCC) has characteristics of good flow-ability, non-vibrating and self-compacting. It is the optimum to be used in concrete members with densely distributed steel bar and concrete is inconvenient to be vibrated. The mixture ratio of design grade of C20 and C40 SCC commonly used in project is given after trial mix. The compression stress-strain relation of SCC prism is obtained by MTS. The Mechanical property indexes of SCC are got. The ultimate compression strain of the extreme fiber is acquired by testing beam made of SCC, and the relation between the ultimate compression strain of the extreme fiber in flexural member and the strain at the peak of the stress-strain curve subjected to uniaxial compression is given.
Thermal Stability and Dynamic Mechanical Behavior of Nano-SiO2/Phenol Formaldehyde Resin Nanocomposites
Authors: Yu Chuan Bai , Wei Chun , Pan Dong Ming
Published: November 2010

The objective of this research was to investigate thermal stability and dynamic mechanical behavior of nano-SiO2/phenol formaldehyde resin (PF) nanocomposites with various nano-SiO2 at 2 wt% loading content. The nano-SiO2/PF nanocomposites were fabricated by two-roll compounding and compression molding technology. The storage modulus (E′) at the starting point of 50 was increased by adding various nano-SiO2 into PF matrix. The E′ of the nanocomposite with only 2 wt% of SiO2 synthesized under ultrasonic irradiation (U-SiO2) was 2 times higher than that of the control PF. Thermal expansion and the coefficient of thermal expansion of nano-SiO2 loaded nanocomposites were lower than that of the control PF in the range of 100–200 and 200–250 . Thermogravimetric analysis demonstrated that the thermal stability of nanocomposites was evidently enhanced. In comparison, U-SiO2 reinforced nanocomposites showed higher thermal properties than those reinforced by mesoporous silica (SBA-15) and SiO2 synthesized by stirring (S-SiO2).
Research on Pavement Characteristics of Epoxy Resin and Rubber Modified Asphalt
Authors: Zhang Rong Hui , Duan Jing Jing , Yin Ying Mei
Published: November 2010

An asphalt modified by epoxy resin and rubber has the following improved properties: the softening point is 70 , elastic recovery rate is 80%, and kinematic viscosity at 175 is 2879.1mm2 /s. In order to solve the early curing in the process of mixing, storage and transportation, methyl hexahydrophthalic anhydride(MHHPA) was used as the curing agent. A reflective cracking caused by traffic load simulation test was established with the objective to compare the propagation speed of reflective crack of three different structure asphalt mixture samples. The results showed that the sample with epoxy resin and rubber used as stress-absorbing layer can obviously delay reflective cracking, improve the pavement performance and prolong the road life. Furthermore, the results of Marshall test, immersion Marshall test and Rutting test were consistent with the results of the reflective crack simulation test.
Preparation and Performance Research of Thermosetting Heat-Reflective Coating for Asphalt Pavement
Authors: Cao Xue Juan , Tang Bo Ming , Zhu Hong Zhou , Li Wen Zhen
Published: November 2010

Taking modified unsaturated polyester as the matrix resin, methyl ethyl ketone peroxide (MEKPO) and cobalt naphthenate as the redox system, and TiO2, SiO2 and hollow glass beads as the functional fillers, a thermosetting heat-reflective coating with good temperature-reduction effects and wearing resistance, which can be quickly solidified under the room temperature has been produced. In accordance to the research, the amount of solidifying agent and accelerant has great bearing on the gelation time of the coating, and the optimum usage for this system of which will be: 2.5% cobalt naphthenate and 2% MEKPO or 3% cobalt naphthenate and 2% MEKPO; as the increase of the fillers, the temperature reduction effects will be quickly enhanced at the beginning, and then tend to be stable, when the quantity of the fillers is less than 10%, the covering effect of the coating is not obvious, when it is more than 20%, construction difficulties will occur because of the excessive viscosity of the coating. Fillers of 14% with low viscosity and better temperature reduction effect is recommended; as the ratio of TiO2 to SiO2 decreases, the temperature reduction effect of the coating is weakened while the abrasion resistance strengthened and the glossiness reduced; the addition of hollow glass bead can better realize the temperature reduction of the coating, however the glossiness of which will be increased; Colored pigments have slightly negative impact on the temperature reduction of coating. The prepared coating has good abrasion resistance, and can reduce the pavement temperature by almost 10 during hot seasons when it is applied on pavement.
Effect of Technical Parameters on Preparing for Vanadium Nitride
Authors: Yu San San , Li Wen Xiu , Ji Zhi Ling , Fu Nian Xin , Sui Zhi Tong
Published: November 2010

In this paper, the producing process of using V2O3 as raw material to obtain vanadium nitride was analyzed through the predominance area diagrams. The analysis shows that VN-phase can be accessed in the conversion process of V2O3 by controlling gas phase composition and temperature of the reaction system and the one-step method preparing for vanadium nitride is feasible. Effect of technical parameters on nitrogen content of products is investigated. The temperature of the reaction system has prominent influence on the nitrogen content of products, and the reaction is very sensitive to temperature. The quantities of nitrogen increase first and decrease later with increasing the reactive temperature, and the result researches the optimum at 1673K. The nitrogen content of the products tended to be constant after soaking over 2 hours at 1673K.Experimental observations shows that additives can increase the nitrogen content of VN. However, the effect of various additives on the nitrogen content is different. Among the additives referred in this paper, the effect of the iron powder, compounds of alkaline earths and NH4Cl are superior.
The Growth, Surface Topography and Curie Temperature in Ni Thin Films: Kinetic Lattice Monte Carlo Simulation
Authors: Zeng Ling Jun , Shen Shuang Juan , Feng Qian , Zhang Jian Min , Chen Zhi Gao , Huang Zhi Gao
Published: November 2010

Based on the Monte Carlo (MC) simulation, the film growth and magnetic properties of Ni (100) films are investigated. The simulated results indicate that the surface roughness of the Ni films drops with the increase of the substrate temperature and the decrease of the deposition rate. The Curie temperature Tc is greatly influenced by the surface roughness and size of Ni films. Moreover, it is found that the Curie temperatures of the films are related to the mean coordination number Z and the surface roughness r. The simulated results explain the experimental facts well.
Cement-Based Composite with Carbon Nanotubes Reinforcement Tailored for Structural Damping
Authors: Luo Jian Lin , Duan Zhong Dong , Zhao Tie Jun , Li Qiu Yi
Published: November 2010

Cement-based composites filled with some multi-walled carbon nanotubes (MWNTs) (MWNT/CC) were fabricated using surfactant enwrapping, ultrasonic treatment, and subsequently intensive shear mixing. The damping capacities of the cured nanocomposites were characterized with forced vibration testing and half-power bandwidth identification method. Results show that, the MWNTs can greatly enhance the structural damping capacity of the MWNT/CC beam with balanced strength reinforcement. There exists 44.5%, 10% increase in the damping ratio, and fundamental frequency of the MWNT/CC with 1.0 wt% MWNTs addition, along with strength reinforcement, as compared to the reference, respectively.
Smart Green Composite: Effect of Cuttlebone Particle on the Mechanical Properties of NR Vulcanizates
Authors: Klungsuwan Pontawit , Poompradub Sirilux
Published: November 2010

The purpose of this study was to investigate the reinforcement effect of the cuttlebone particle on the mechanical properties of natural rubber (NR) vulcanizates. The extraction of organic compound from the cuttlebone was prepared demineralization and deproteinization methods. The obtained chitin had been characterized by Fourier Transform Infrared Spectroscopy (FTIR). The mechanical and thermal properties of NR composite materials were investigated. The reinforcement effect of cuttlebone particle in NR composite was comparable with that of commercial CaCO3 as a reference. After thermal aging, the tensile properties of composite material were decreased. The presence of organic component was speculated to give a good interaction effect of cuttlebone particles to NR as revealed by Scanning Electron Microscopy (SEM).
Mechanical and Shielding Properties of an As-Cast New Pb-B Shielding Composite Materials
Authors: Duan Yong Hua , Sun Yong , Peng Ming Jun , Guo Zhong Zheng
Published: November 2010

The new type of Pb-B shielding alloys with high tensile strength and hardness were prepared by casting. The microstructure and morphology of the Pb-B alloys were investigated by scanning electron microscope (SEM) analysis. Mechanical properties and radiation shielding effect of the alloys were compared with other Pb-based shielding alloys. The results indicate that the tensile strength and hardness increased up to 116 MPa and 160 HB with the 1.0 wt.% content of B. The fractographic examination conducted by SEM indicate that the Pb-B alloys are in form of plastic fracture, and the fracture model changes from the dimple to the intergranular quasi-cleavage with the increasing of B content. Furthermore, the composites are of the excellent shielding properties. Especially at the thickness of 20 mm, the shielding ratios for γ-ray and neutron reach 49.7% and 92.7%, respectively.
The Seismic Behavior of Strengthened Joints between Concrete-Filled Steel Tubes and Beams Based on the Numerical Simulation Technology
Authors: Chu Yun Peng , Yao Yong , Xiao Shu Lian , Chen Yue
Published: November 2010

As a key part in concrete-filled steel tubular frames, the seismic behavior of joints between concrete-filled steel tubes and beams needs more research because of the complexity of stress under the reciprocating load. the behavior of 9 strengthened joints connecting concrete-filled steel tube with H-shaped steel beam have been analyzed under reversed cyclic loading condition by using finite element analysis software ANSYS, and the result show that: (1) The ultimate bearing capacity, energy dissipation capacity and ductility of strengthened joint are obvious better than that of ordinary welded joint; (2) Compared to concrete-filled steel tube the ultimate bearing capacity, energy dissipation capacity and ductility of double-layer concrete-filled steel tubes are better; (3) For the joints connecting double-layer concrete-filled steel tubes with beams, the shape of inner tube have certain effect on the ultimate bearing capacity but little on the energy dissipation capacity and ductility. (4) The shape of stiffened plate has significant influence on the ultimate bearing capacity, energy dissipation capacity and ductility of nodes.
Study on Vibration Alleviating Properties of Different Fiber Reinforced Polymer Concrete
Authors: Bai Wen Feng , Li Chuan Feng , Yang Yong , Hu Qian Kun
Published: November 2010

Polymer concrete (PC), because of its good vibration alleviating properties, is a proper material for elementary machine parts in high-precision machine tools. Strengthening fibers were applied in PC to improve its mechanical properties, and the material obtained is called fiber reinforced polymer concrete (FRPC). The best parameter to estimate the vibration alleviating property is damping ratio. Orthogonal tests were carried out to prepare FRPC specimens with different fibers. How strengthening fibers affect vibration alleviating properties of FRPC was studies basing on the experiment results.
Interaction and Enthalpy Recovery Behavior in Polymer Blends of Polysulfone and Carboxylated Polysulfone
Authors: Jiang You Qing , Zhang Yun Bo
Published: November 2010

Polymer blends of a binary system with limited miscibility are a kind of different surface structure polymer blends which main chains are same as one. The blend of polysulfone (PSf) and carboxylated polysulfone (CPSf) had been made in the solvent of dimethylacelamide (DMAc) or N-methylpyrrolidinone (NMP). The chemical polysulfones containing 0.5,1.0,1.5 and 2.0 carboxylated groups per repeat unit were mixed with Udel 300 polysulfone. The equilibrium time of two-phase polymer in solution presents their degrees of limited miscibility. The two- phase polymers could transfer as miscible blends when they had been annealed at 170 for above 6 days. Annealing of blends below the grass transition temperature(Tg) results in a decrease in enthalpy that is recovered during heating. The enthalpy recovery is visible as an endothermic peak in a differential scanning calorimeter (DSC) scan. The position of this peak depends on the composition of two-phase and on the structure of material itself. Two-sample cells were co-tested in same time for getting several Tg of limited miscible polymer blend and its component respectively. PSf/CPSf polymer blends in liquid-liquid phase separation and molecular weight distribution to be tested by High Performance Gel Permeation Chromatography (GPC). The polymer blends were showing S-O-C strength absorbance between 1000-769/cm and 3300-2500/cm to be detected by Infrared Absorption Spectrum (IR) analysis. Therefore, the reaction and enthalpy of limited miscibility between two-phase of polymer blend PSf/CPSf can be described in the paper.
Effect of Rosin Ester on Water-Resistant Adhesion Oximized RTV-1 Silicone Rubber Sealant
Authors: Luo Sui Lian , Hu Yang Shan , Shi Guang , Pan Hui Ming
Published: November 2010

It is necessary to improve the adhesion of the cured rubber to a substrate as it is used extensively. It is well known that an improvement in adhesion can be realized by incorporating in the composition a sliane or siloxane. Although the composition provides good adhesion to many kinds of substrates, it has been found that the adhesive bond degrades rapidly under wet conditions. To be solved it, rosin eater was incorprated in the silcone ruber in the paper. Increasing the content of rosin ester could induce a relative high adhesion in hot water. Moreover, when the content of modified rosin pentaerythritol ester was above 4.5 phr, the immersion days in hot water before adhesive failure occured were three times than that of non-additive rosin esters.
A Novel Green Tape with High Solid Content Prepared by Aqueous Tape-Casting
Authors: Wang Shuang Xi , Ouyang Xue Qiong , Wang Ya Dong , Zheng Qiong Na , You Jing
Published: November 2010

Green tapes were prepared by aqueous tape-casting method with binders of polyvinyl alcohol, styrene-acrylate emulsion and the mixed binders, respectively. Effects of solid content and binders on viscosity of the slurry were investigated by digital rotary viscosimeter. Results show that solid content should be lower than 60wt % with the binder of PVA; solid content could achieve the maximum 73wt% by tape-casting using emulsion as binder. Furthermore, slurry with solid content up to 75wt % had been successfully prepared by tape-casting using mixed binders. Mixed binders are promising additives to produce high solid content green tapes with smooth surface, adequate strength and very good flexibility.
A Study on 3D Isolation Effect on High-Rise Building Subjected to Near-Field Ground Motions
Authors: Liu Jie Ping , Zhang Ling Xin , Meng Qing Li
Published: November 2010

Isolation technology is widely applied in civil engineering nowadays, while it is indicated by seismic damage investigations that the effect of vertical motion on buildings under earthquake couldn’t be ignored. In order to study the 3D isolation effect on high-rise buildings subjected to near-field ground motions, the finite element analysis of an 11-story reinforced concrete frame-shear wall building is conducted, three ground motions are selected, three kinds of structural model are calculated, which are without isolation, with horizontal isolation and with three-dimensional isolation. By analyzing and comparing the seismic response results of models, the 3D isolation effect is studied, and some conclusions are obtained.
Effect of Microstructure on Transport Properties of Nano-Polycrystalline La0.7Sr0.3MnO3-D Films
Authors: Jiang Shao Qun , Ma Xin Xin , Liu Jian Dang , Ye Bang Jiao , Wang Ze Hua , Zhou Ze Hua , Yi Yu
Published: November 2010

The effect of microstructure on transport properties of nano-polycrystalline La0.7Sr0.3MnO3-δ films, which were prepared by DC magnetron sputtering at various working pressures and followed by air annealing at 973K for 1h, has been investigated. The result indicates that the change of working pressure can change the microstructure, metal-insulator transition temperature (TIM) and peak resistance but does not change the transport mechanism for the films. The vacancy defects have an important effect on the transport properties of the films. Higher working pressure tends to decrease the density of vacancy defects. Low vacancy defects account for the high TIM and low resistance of the films. In the region of T > TIM, the charge carriers are moving in variable range hopping mode. The behavior of resistance decreasing with the increasing of temperature at low temperature (T<23K) can be explained on the basis of thermal excitation tunneling effect. The minimum resistance results from the combined effect of the tunneling effect and intrinsic metallic transport characteristic of the films.
Research on Earthquake Resistant Materials in Mountain Tunnels Crossing Fault
Authors: Wang Qiong , Guo En Dong , Wang Zai Rong , Yang Dan
Published: November 2010

Seismic damage, such as falling, fissure and dislocation of the lining may happen at location of fault movement. The model of enhancing stiffness and that of adding seismic decrease layer are built by the finite element software MIDAS to compare the two earthquake-resistant methods. Some useful results are obtained: a)The displacement is decreased, but the peak acceleration and first principle stress of the lining are increased in the model of enhancing the lining materials stiffness. b) The displacement, peak acceleration and first principle stress are all decreased in the model of adding seismic decrease layer. c) The max-displacement when using c20 as lining material or adding seismic decrease layer is in the area of fault, but that of the model when using c40 as lining material is in the area of entrance.
Studies on the Properties of Epoxy Resins Modified with Novel Liquid Crystalline Polyurethane
Authors: Huang Zhi Yi , Lu Shao Rong , Yang Zhi You , Yu Chun He , Guo Dong
Published: November 2010

Liquid crystal polyurethane (LCPBI) containing biphenylnate and imide units was synthesized and characterized and used to modify the conventional epoxy resin (E-51). Experimental results revealed that the impact strength of the epoxy resin modified with LCPBI was 2.5 times higher than that of unmodified epoxy resin, and the tensile strength as well as the bending strength was also improved. The thermal decomposition temperature of modified systems was also 15-20oC higher than that of the unmodified system, and the fracture structures of the blends was investigated by SEM.
Research of Properties and Preparation on Zero-VOC Acrylic Elastic Emulsion
Authors: Xu Qian , Wen Shao Guo , Liu Hong Bo , Wang Ji Hu , Shen Yan
Published: November 2010

The core-shell acrylic emulsion was synthesized，with P(MMA/BA) as core，and with P(2-EHA/MBA/HPA) as shell. The influence of the mass ratio of core/shell on mechanical properties was investigated in detail. The high elongation at break proved that the emulsion may have a potential application in coating industry, afforded by HPA as functional monomer. However, when the amount of HPA exceeds 1.5 wt. % to the total monomers, the emulsion will become unstable and precipitation occurs.
Preparation and Microscopic Analysis of Polyurethane Elastomer Made by Salix psammophila
Authors: Huang Jin Tian , Li Ya Bin , Tie Kun Ling
Published: November 2010

In this paper, the degradation of Salix psammophila is used to make the polyurethane elastomer and study on the process involving changes in molecules with SPM. Compared with the pure polyurethane, it can be concluded that the polymerization of particles′ size, height and measurement have got bigger visibly. But the cured particles change nothing and retain the natural polymer’s linear permutation. And this polyurethane elastomer′s fracture profile is brittle.
Crack Pattern Evolution and Complexity of Brittle Failure of Rock
Authors: Hao Sheng Wang , Wang Guo Wei , Wang Bing
Published: November 2010

Optical Microscope and SEM(Scanning Electron Microscope) are used to observe the crack evolution of rock under compression. Two kinds of rock (marble and granite) are investigated. The evolution of crack pattern shows that localization is a key factor inducing brittle failure. Crack of granite readily tends to localize and show more brittle. Contrarily, randomly distributed cracks induced by compression load results into the low brittle of marble. The mechanism underline this phenomenon is that marble has higher heterogeneous than granite. So, the key point to describe the brittle failure mechanism of rock is to determine the micro-mechanical and the damage evolution properties.
The Mechanical Properties of Modified Attapulgite Reinforced Nature Rubber and Styrene-Butadiene Rubber Nanocomposites
Authors: Wang Ji Hu , Liu Hong Bo , Wen Shao Guo , Shen Yan
Published: November 2010

Attapulgite (AT)/natural rubber (NR)/ styrene-butadiene rubber (SBR) nanocomposites have been prepared after attapulgite was modified by different coupling agent. The treatment of AT caused the adhesion between AT nanorods and the nature rubber/styrene-butadiene rubber was improved, which enhanced the tensile properties of the matrix. The tensile strength of composites attained 15.6 MPa after AT was modified by 3%wt Si-69 coupling with addition of 20 phr.
The Effect of IrO2 Doping on the Structure and Magnetic and Magnetotransport Properties of La0.7Ca0.2Sr0.1MnO3 Composite
Authors: Wei Fen Fen , Xiong Cao Shui , Gou Ke Jin , Liao Hui , Hou Juan
Published: November 2010

La0.7Ca0.2Sr0.1MnO3/xIrO2 (LCSMO/xIrO2) compounds were fabricated by solid state reaction method. X-ray diffraction (XRD), vibrating sample magnetometer (VSM) and Dc four probed method were used to investigate the structure, magnetic and magnetotransport properties. The results show that at low doping level (x≤0.15) IrO2 goes into the perovskite lattice substituting Mn in LCSMO, but at high doping level (x≥0.20) some part of the IrO2 substituted for Mn4+ in LCSMO lattice and the remainder resided in the grain boundaries in the form of IrO2. LCSMO/xIrO2 composites are influenced remarkabled by the IrO2 doping. With increasing IrO2 addition, the magnetic moment (s) decreases and Curie temperature (TC) decreases first, and then rises slowly of the compounds; In the doping range of 0~0.35, the resistivity rises first, and then decreases slowly, furthermore, the resistivity versus appears double peaks with increasing IrO2 addition. At room temperature, the magnetoresistance (MR) of the composites have been improved remarkably.
Gd2O3 Added Glass-Ceramic Composite for the Improvement of Energy Storage Density through Controlled Crystallization
Authors: Zhou Yi , Tang Qun , Luo Jun , Zhang Qing Meng , Wang Lei , Du Jun
Published: November 2010

Crystallization of a glass containing high dielectric performance components can be controlled in the nucleation and growth processes in order to meet the requirements of enabling the glass-ceramic dielectric composites to obtain the desired high electric energy storage densitiy. In this paper, the controlled crystallization technique was employed to synthesize glass-ceramic composites with addition of Gd2O3 in BaO-Na2O- Nb2O5- SiO2 glass system. The results show that both the dielectric constant and the breakdown strength of the glass-ceramic composites demonstrate an increasing tendency with the addition of Gd2O3 from 0 mol% to 7 mol% (relative to SiO2), being responsible for remarkable improvement of the energy storage density of the glass-ceramic composites from 1.7 J/cm3 to 4.7 J/cm3.
Cure Kinetics and Thermal Property of UV-Curable Polyester Nanocomposites Coating Modified with MAP-POSS
Authors: Gao Jun Gang , Sun Bei Bei , Li Xing
Published: November 2010

The UV-curable unsaturated polyester (UPR) was modified with glycidyl methacrylate and methylacryloylpropyl polyhedral oligomeric silsesquioxanes (MAP-POSS), and the cure kinetics of MAP-POSS/UPR system was investigated by non-isothermal DSC. The result shows that UPR, glycidyl methacrylate and MAP-POSS have very good compatibility and can co-cure in free radical polymerization.The curing reaction can be described by a two-parameter autocatalytic Šesták-Berggren (S-B) model. The average reaction activation energy Ea for 6% and 9% MAP-POSS content is 73 kJ/mol and is lower than 0% ( about 82kJ/mol). The mechanical loss peak temperature Tp of curing nanocomposites increase with increasing MAP-POSS content and has a highest value when MAP-POSS content is 9%, which is 114.1 oC and higher about 12 oC than pure UPR.
Experiment Study on Mechanics and Pore Structure of Steel Fibre Reinforced Concrete
Authors: Wang Yan , Niu Di Tao , Miao Yuan Yao , Jiao Nai Qi
Published: November 2010

The concrete microstructure can affect its macroscopic properties, such as the strength and durability, etc. Based on the experimental study of cube compressive strength of steel fibre reinforced concrete, splitting tensile strength, flexural strength, and using by mercury intrusion method to test the pore structure of steel fibrous, this paper analyzes the influence of fibre on concrete pore structure. And then on mechanical properties of concrete from microcosmic perspective.
Preparation and Properties of the PTT/ABS/SCF Composites
Authors: Run Ming Tao , Zhang Hong Sheng , Li Xin , Cui Fu Yuan
Published: November 2010

The morphological, mechanical and rheological properties of poly(trimethylene terephthalate)(PTT)/maleinized acrylonitrile-butadiene-styrene (ABS-g-MAH)/short carbon fiber (SCF) composites were investigated by the scanning electron microscopy(SEM), universal tester, impact tester and capillary rheometer, respectively. The SEM images of the composites’ fracture surface show that the fracture surface is rough and SCF are randomly dispersed in the matrix resin, and there is a good interfacial interaction between SCF and PTT. The composites show the maximum tensile strength when adding 10-23% SCF into PTT/ABS blends. The rheology results show that the composites melt are pseudo-plastic fluid, and the melt apparent viscosity of the PTT/ABS/SCF composites increases with increasing SCF content.