bluuebunny/crossref_metadata_2025 huggingface dataset:
Oil Source Valve Optimized Design and its Application in Mechanical Loader
Authors: Wei Yu Ping
Published: October 2014

The operating system of loader working device is composed of the boom and bucket. It is operated mainly through multi-way valve axis manipulation, this kind of way is force-large, labor-intensive, but is low efficient. So it is necessary to optimize the oil source valve. Using the hydraulic pilot to control loader multi-way valve to optimize in the loader is safe, comfortable, furnished spirit and can achieve variable speed. Working hydraulic system uses a small flow pilot circuit control. The main oil is controlled by high pressure and large flow, and then the operating force of the working device is reduced greatly.
Detection of the Chinese Rice Wine Using an Electronic Tongue
Authors: Lu Xiao Li , Cai Xiao Qing
Published: October 2014

An electronic tongue was employed to detect different brands of Chinese rice wine. The results showed that all of the seven classes of Chinese rice wine can be discriminated by Discriminant Factor Analysis (DFA) and Principal Component Analysis (PCA). Based on Artificial Neural Network (ANN), the electronic tongue can predict the marked age of Chinese rice wine, and the accuracy of prediction was above 90% averagely.
Study on Characteristics of Simple Inductance Circuit under Cut-Off Discharge Mode
Authors: Xue Hong Ye , Ma Xiang Yang
Published: October 2014

Through the Matlab simulation results shown that In this paper a simple inductor circuit under cut-off discharge model presented, was more in line with the situation of the circuit discharge. Design of a power supply according to the model passed the spark test and power supply circuit meets intrinsically safe requirements.
Damage Effectiveness Evaluation of Missile and Artillery Air Defense Group
Authors: Zhang Pei Chao , Cheng Yuan Zeng , Wang Jie
Published: October 2014

Currently, missile and artillery air defense system under the conditions of the network has become a very important air defense weapon system, and play an unprecedented role in modern warfare process. To develop high damage performance missile and artillery air defense system has become common goal. It is necessary to study the impact of missile and artillery air defense system damage performance for improving damage probability of missile and artillery air defense system.
A Detection Algorithm for Projectile Target
Authors: Shang Zai Fei , Wang Chun Ping
Published: October 2014

For consistency of performance in the shape of the projectile targets, a projectile target detection algorithm is presented based on HOG (Histogram of Oriented Gradient) characterization algorithm. First, detecting the bullet image corner, and secondly, by Mean-shift algorithm improves the corner position accuracy and reduces the number of corner points, finally, applying support vector machines to extract the projectile targets. Compared with the traditional small target detection algorithm, the algorithm describes the targets more accurately, along with better real-time performance. Simulation, the projectile target detection rate of over 80% and verify the effectiveness of the algorithm.
A Kind of DWT Domain Image Digital Watermarking Algorithm Research
Authors: Liu Tao
Published: October 2014

An image-adaptive watermarking algorithm based on wavelet transform was proposed. At first, A digital image used as watermarking was scrambled. Next, the original image was decomposed by discrete wavelet transform,and in accordance with the characteristics of human visual system, wavelet decomposition in the low-frequency domain, Methods which average of adjacent domain instead of single wavelet decomposition coefficients was used to estimate and quantitative, watermarking was adaptively embedded in wavelet coefficients of low-frequency domain. At last, the simulation experimental results show that the algorithm for a variety of conventional image processing has good robustness.
Synthesis of Phosphonate-Containing 2-Methyl-1,5-Diaminopentane Derivatives
Authors: Li Xiao Chuan , Gong Shan Shan , Sun Qi
Published: October 2014

An improved method for the synthesis of α-aminophosphonate based on the Kabachnik-Fields reaction has been developed. The Kabachnik-Fields reactions for the synthesis of the title compounds were investigated in different solvents. The results showed that the solvent-free conditions was optimal for synthesis of this type of compounds.
Construction Study on the Public Elderly-Care Facility in Xi’an
Authors: Jing Huai Rui , Lin Yun Ting , Zhang Xin Yang
Published: October 2014

Nowadays the sharp increase of population of the old in Xi’an has become a social spot. This paper will make the public elderly-care facility in Xi’an as the object. Give an overview of the basic situation and characteristics of endowment facilities throughout the region and summarize the problems existing in this area through detailed analysis of two typical facilities in the third part.
Construction Research with a New Research Method for Determining the Traffic Impact Scope
Authors: Wang Zhi Peng , Lv Yong Bo
Published: October 2014

Traffic impact analysis is the analysis and evaluation of construction project's impact on the surrounding road network traffic load, researching on the internal relations of urban land usage and transportation, revealling the laws and exploring how to coordinate the relationship between them. It’s a effective means to solve the problem of urban traffic. It has been promoted in many cities in China, its important role also increasingly cause the competent attention of the department of city.
Design and Kinematic Analysis of Planar Four-Bar Linkages with an Object Oriented Python Program
Authors: Sun Ming
Published: October 2014

A python program is developed for analysis and design of planar four-bar linkages. The program contains one main class for design and analysis of common use. It allows users to make the analysis of position, velocity, acceleration for any four-bar linkages, and show an animation to simulate the motion of planar mechanism. It offers a reference to the beginner for teaching and learning mechanism design and analysis. This program also allows user make changes and improvement on default code for application.
Aerodynamic and Numerical Study on the Influence of Spike Shapes at Mach 1.5
Authors: Li Yong Hong , Tang Xin Wu , Zhou Wei Qun
Published: October 2014

Taking into account the issue of configuration or aerodynamic heating, most supersonic and hypersonic flight vehicles have to use the blunt-nosed body. However, in supersonic especially in hypersonic flow the strong bow shock ahead of the blunt nose introduces a rather high shock drag that affects the aerodynamic performance of the vehicles seriously. A spike mounted on a blunt body during its flight pushes the strong bow shock away from the body surface and forms recirculation flow with low pressure ahead of the body surface, and then decreases the drag. The drag reduction effects of spikes in high supersonic and hypersonic flow had been validated through experimental and numerical methods. In order to analyze the influence of the spike on aerodynamic characteristics at low supersonic (M=1.5) flow past blunt-nosed bodies, numerical studies were carried out which included the influence of the spike shape, the analysis of the fluid flow structures and the effect on the aerodynamic characteristics of a blunt body.
The Analysis of Direct Numerical Simulation and Experiment in Critical Point of Transitional Flow
Authors: Wang Jun , Du Guang Sheng , Liu Yong Hui
Published: October 2014

In order to study the lower critical point in transitional area of pipe, we used the method of direct numerical simulation to simulate fluid flow and contrasted it with experiment. The result showed that the flow state is close to laminar. Along the pipe axis, the change of pressure is not obviously. The changing rate of axial velocity U near wall region was significantly greater than in the mainstream area, it proved the important role of viscous force.
Research on Information Fusion Method to Improve the Measurement Precision of High Speed Vehicles Anti-Collision Distance
Authors: Xu Jiang Chun , Huang Sheng Wang , Chen Yan , Zhang Yun Wei , Lei Jin Hui
Published: October 2014

With the continuous development of the Internet of things technology, the high-speed vehicles to prevent rear-end collision warning system which is from the traditional passive to the current vehicle-to-vehicle communication active warning also continues to develop. In this paper, a vehicle ranging system is composed of Zigbee wireless communication and GPS positioning system. Through setting maneuvering model, establishing ranging system state equation and observation equation, error model, integrating the two vehicles’ distance, relative velocity, relative acceleration and the distance error, we can get the vehicle distance estimation by using of centralized Kalman filter techniques. The simulation results show that the method can provide vehicle-to-vehicle communication ranging system with the high precision data of anti-collision distance. The system has good tracking performance.
Research for Uniformity of Insulation Layer on Communication Cable Online Testing Control System
Authors: Cai Jie
Published: October 2014

With the feathered development of communication and networks,the needs for the communication cable is highly increased,while the assurance of the communication cable’s quality is an important work for every cable factory to slove.The major research of this project is aim at the problems about the dynamic testing and the uniformity of cable insulation layer,and then the online test control system were designed.The control is mainly use OMRON's CS1G-H PLC as the central control system, at the same time control system uses touch-screen to realize the man-machine dialogue,which can effectively monitor the operational status of the equipment.Through the programming, simulation, simulation experiment for this system in the laboratory,proved that this system can be in motion, achieve the desired functionality. At the same time this system can be used for the promotion and use.
Fault Diagnosis Based on Multi-Layer Structure Wavelet Neural Networks in Attitude Heading Reference System
Authors: Jiao Zhun , Zhang Rong
Published: October 2014

According to the structure feature of aircraft’s attitude heading reference system and procedure of fault diagnosis, this paper sets up multi-layer neural network model structure for fault diagnosis of complex equipment, and applies the model to the fault diagnosis of attitude heading reference system in aircraft. The conclusion is that the method can effectively reduce the complexity of fault diagnosis for complex system, and imp rove diagnosis rate and efficiency of attitude heading reference system. At the same time, it also provides a new method and theory to diagnosis the non-linear system.
Study on Dynamic Marshalling and Coupled Control of China’s High-Speed Electric Multiple Unit
Authors: Liu Yang , Li Chang Xian , Zhang Tong , Sun Yan Nan
Published: October 2014

In order to reduce operation cost and improve transport capacity of China high-speed railway, train dynamic marshalling often need to be implemented between different kinds of China’s high-speed Electric Multiple Units (EMUs). Based on the operation situation of China high-speed railway, this paper analyzes the market demand and feasibility of dynamic marshalling between different kinds of EMUs, and describes the principle how to realize it by using TCN and UIC network communication technology. Some key problems which need to be solved in the process of realizing coupled control between different kinds of EMUs are pointed out, and corresponding suggestions how to solve these problems are proposed as well. Moreover, according to the technical development trend of the EMU, this paper predicts the possibility of using network communication technology based on real-time Ethernet to realize EMU marshalling and coupled control.
2-Naphthalenesulfonic Acid Adsorption on Composite Weakly Basic Resin
Authors: Yu Shan , Li Chang Hai , Jia Dong Mei
Published: October 2014

The hydroxyl alumina impregnated weakly basic resin composite (D301Al) successfully prepared through incorporation of hydroxyl alumina into the D301 resin for 2-naphthalenesulfonic acid (2-NSA) removal from aqueous solution. The structure of D301Al was examined using scanning electron microscopy and Fourier transform infrared spectroscopy. The adsorption behaviors of 2-NSA on D301Al were investigated by static adsorption experiments. Effects of pH of solution, temperature and contact time were determined. The results indicated D301Al reached the maximum adsorption capacity to 2-NSA with pH 2.4. Nonlinear regression was used to estimate of Langmuir and Freundlich model parameters. And the Langmuir model can give a satisfactory fit of the experimental equilibrium data. The kinetic studies indicated that the adsorption of D301Al for 2-NSA can establish adsorption equilibrium at 8 h. The pseudo-first-order and pseudo-second-order rate models could characterize the kinetic data of 2-NSA adsorption on D301Al.
The Design of Embedded Ethernet System Based Microcontroller
Authors: Huang Song Lin , Cui Jian Zhong
Published: October 2014

With the wide application of Internet technology, the embedded system is becoming more and more to develop in the direction of the network. The combination of embedded devices and the Internet represents the future direction of development of embedded systems. In this paper, a microprocessor-based embedded Ethernet solution was presented. The collaborative software and hardware design thought was used in system. TheμC /OS-II operating system, joined the TCP/IP protocol stack, was transplanted to the embedded Ethernet platform. The test results proved that the embedded Ethernet system network communication is stable and reliable.
A Variables Clustering Based Differential Evolution Algorithm to Solve Multistage Goal Programming Model in Defense Projects Portfolio
Authors: Zhou Yu , Li Yong Bin , Shi Zhong Zheng , Li Zheng Xin , Zhang Lei
Published: October 2014

The multistage goal programming model is popular to model the defense projects portfolio optimization problem in recent years. However, as its high-dimensional variables and large-scale solution space, the addressed model is hard to be solved in an acceptable time. To deal with this challenge, we propose an improved differential evolution algorithm which combines three novel strategies i.e. the variables clustering based evolution, the whole randomized parameters, and the child-individual based selection. The simulation results show that this algorithm has the fastest convergence and the best global searching capability in 6 test instances with different scales of solution space, compared with classical differential evolution algorithm (CDE), genetic algorithm (GA) and particle swarm optimization (PSO) algorithm.
Projection Method for Material Selection Problem with Triangular Fuzzy Numbers
Authors: Yang Lian Wu , Xiao Shi Xiao , Yuan Shao Liang
Published: October 2014

The aim of this paper is to develop a new method for the material selection problem, which is important for the product design. Material selection problem is actually a multi-attribute decision making (MADM) problem which contains many influence factors. The new material selection method is an extension of projection method with evaluation attribution values expressed with triangular fuzzy numbers. Coefficient of variation method is used to determine weights of evaluation attribute. A grinding wheel abrasive material selection problem is used to illustrate the effectiveness and practicability of the proposed method.
A General Model for Low-Illumination Video Enhancement
Authors: Xiao He , Deng Li Ping , Li Jia
Published: October 2014

In order to improve the visual effect of different regions within a video frame, in this paper, we propose a general and effective enhancement model for low-illumination video. The proposed method firstly is to change color space from RGB to HSI color space, Then enhance the I channel by nonlinear tone-mapping function. At the same time, in order to reduce the color distortion, we enhance the saturation component S. Finally, color image is reconstructed. Experimental results show the effectiveness and robustness.
Applied Technology in Multidimensional Color Image Scaling Based on NASS in a Quantum System
Authors: Li Hai Sheng , Song Kai
Published: October 2014

In this study, an important geometric transformation, multidimensional color image scaling based on an n-qubit normal arbitrary superposition state (NASS), is put forward. In order to reduce the complexity of implementation of image scaling in a quantum system, nearest neighbor interpolation algorithm is chosen to implement image scaling up. And the corresponding quantum circuit of implementation is proposed. Finally, we discuss measurements of the part qubits of a NASS state to realize image scaling down. The paper explores theoretical and practical aspects of image processing on a quantum computer.
Construction Research on Multi-Threshold Segmentation Based on Improved Otsu Threshold Method
Authors: Wang Yan Qing , Zhuang Lu Lu , Shi Chao Xia
Published: October 2014

The aim of unstructured road detection is the recognition of road region and the tracking of road boundary. An improved Otsu threshold method available in double-threshold segmentation was proposed in this paper to resolve the multi-peaks problem in both complicated background and target. This method remedies the mis-segmentation of Otsu threshold method caused by huge diversity of between-class variances and refines the segmentation precision by matching the proposed Otsu edges with the weighted Canny edges. According to the irregular characteristics of the unstructured road and the requirement of the real-time motion planning for intelligent vehicle, improved Otsu threshold method was proposed. The experiment results in different road environments demonstrated the validity and real-time of the proposed method.
The Application Research of the University Human Resource Systems Based on Virtualization Technology
Authors: Guan Shao Yun , Fan Ye , Lv Hong Lue
Published: October 2014

This paper targets on the existing problems in the University Human Resource Systems such as equipment scattered, utilization lower and difficult to share data etc. It proposes Virtualization Technology achieve maximum results to solve the problems with a minimum of manpower and financial cost. Virtualized servers can make equipment concentration and high utilization. It establishes virtualized interface to share data and meet the needs of various departments’ on-demand services. Moreover it can centralize management of data backup and security.
Applied Information Technology in KBE Based Intelligent Design System for Tricone Bits
Authors: Chen Qing
Published: October 2014

It is presented the knowledge engineering based design process for tricone bits and the principles of intelligent design systems. Based on Teamcenter, using NX system development software, taking full advantage of the existing design standard, design data, and materials such as design experiences, design criteria, tricone bit models accumulated by industry companies, a knowledge driven intelligent design system for tricone bits has been developed. It is a way of effectively reusing industrial product development knowledge, enhancing effectiveness and quality of product design, and achieving product full life cycle management.
An Improved Dynamic Trust Model for Distributed System
Authors: Ye Chong Yang , Zhuang Yi
Published: October 2014

The parallel, sharing and high speed distributed system has become the mainstream of current system architecture, the characteristics of uncentralized management makes more and more people take flexible operations. However, as the nodes in the system are not bound by a central server and resource sharing is a node’s voluntary behavior, the traditional centralized mechanism is not suitable for large-scale distributed system. Aiming at this problem, this paper proposes an improved dynamic trust model for distributed system (IDTrust) to quantify and evaluate the credible degree between nodes. The analysis and simulation results show that the effectiveness of contain malicious nodes and the security aspects of IDTrust are superior to those of current typical methods.
Virtual Machines Scheduling Algorithm Based on Multi-Objective Optimization in Cloud Computing
Authors: Zhu Jian Rong , Zhuang Yi , Li Jing , Zhu Wei
Published: October 2014

How to reduce energy consumption while improving utility of datacenter is one of the key technologies in the cloud computing environment. In this paper, we use energy consumption and utility of data center as objective functions to set up a virtual machine scheduling model based on multi-objective optimization VMSA-MOP, and design a virtual machine scheduling algorithm based on NSGA-2 to solve the model. Experimental results show that compared with other virtual machine scheduling algorithms, our algorithm can obtain relatively optimal scheduling results.
Computation for Equation of States of (Mg0.92, Fe0.08)SiO3 Perovskite Based on Mie-Grüneisen-Debye Model
Authors: Chen Xiu Fang
Published: October 2014

In this paper, the thermal equation of state (EOS) of (Mg0.92, Fe0.08)SiO3is computed by Birch-Murnaghan and Mie-Grüneisen-Debye equations and the related parameters are also analyzed. The value of and has little effect on EOS of (Mg0.92, Fe0.08)SiO3perovskite. The effect of EOS of (Mg0.92, Fe0.08)SiO3perovskite is mainly from the temperature under high pressure. The temperature is higher; the deviation of EOS relative to the PREM model is bigger. The thermal EOS complies with PREM model at T=2000K. The thermal pressure of (Mg0.92, Fe0.08)SiO3perovskite a constant only related to temperature at the lower mantle conditions. At the same time, the EOS of (Mg0.92, Fe0.08)SiO3perovskite is insensitive to the data of and at T=2000K, but when and the thermal EOS is more agreement with PREM model. That is to say, when the value of the and is in the range of 253~273 GPa and 3.69~4.23, (Mg0.92, Fe0.08)SiO3is the perovskite phase, and (Mg0.92, Fe0.08)SiO3perovskite structure remains stable at the mantle conditions.
Applied Technology in Feasibility Assessment of Photoplethysmograph Computing for Heart Rate Variability Application
Authors: Fu Tsu Hsun
Published: October 2014

In response to the problem of mental or physical disorders due to the pace of modern busy life, the heart rate variability analysis is often used as an indicator for assessment. This study indicates the use of electrocardiogram (ECG) and photoplethysmograph (PPG) to capture the heart rate and conduct heart rate variability comparative analysis. We want to use photoplethysmograph to replace ECG for retrieving heart rate of patients. In our experiment, the first observation is to record the autonomic nervous system modulation caused by listening to music with different rhythms and doing exercise. Then we observe the correlation among different heart rate variability under different physical conditions after that. According to the results of the analysis shown that PPG calculated heart rate variability signals are highly related to the results obtained by ECG.
Research on Image Segmentation Technology with Tissue Section Cell Segmentation Algorithm
Authors: Huo Chun Bao , Tong Shuai , Zhao Li Hui , Li Xiang Yun
Published: October 2014

Generally, the effect of cell image that segmented via the threshold value method is not ideal generally; the found cell boundary cannot conform to the cell edge in the original picture well. In this paper, the threshold value segmentation method is improved; apply the judging criterion of gray level difference maximum interval to be the minimum, and conduct secondary treating on the image, and the image’s segmentation effect is more ideal.
Facile Synthesis of Symmetrical Homonucleotides of Antiviral Nucleosides
Authors: Sun Jian , Gong Shan Shan , Sun Qi
Published: October 2014

A facile method for the one-pot preparation of homodinucleotides of AZT and d4T from corresponding nucleoside 5′-phosphoropiperidates with 4,5-dicyanoimidazole (DCI) as the activator has been developed.
Experimental Study of Strengthening and Toughening for Recycled Steel Fiber Reinforced Ultra-High Performance Concrete
Authors: Peng Gai Fei , Niu Xu Jing , Long Qian Qian
Published: October 2014

This paper presents an experimental investigation on mechanical properties (including compressive strength, tensile splitting strength and fracture energy) of ultra-high performance concrete (UHPC) with recycled steel fiber, compared with none fiber and industrial steel fiber reinforced UHPC. Moreover, the microscopic observation of fracture energy was carried out. All specimens were prepared at 0.18 water /binder (W/B) ratio and the dosage of steel fiber was controlled at 60 kg/m3. The results indicate that recycled steel fiber has a significant effect on enhancing strength and toughness of UHPC. And owing to the crimped shape, higher tensile strength (1800-2000 MPa) and appropriate diameter (1 mm) of recycled steel fiber, the steel fibers of UHPRSFRC will not immediately be pulled off and necking phenomenon is distinct.
The Protection of Reinforcing Steel in Concrete by Migrating Corrosion Inhibitor
Authors: Cai J.S. , Chen C.C. , Liu J.Z. , Shi Liang
Published: October 2014

In this paper, the performance of two kinds of migrating corrosion inhibitors on the corrosion behavior of steel in concrete under wet-dry cycle was investigated. The wet-dry cycle duration on the open circuit, current density and impedance of carbon steel imbedded in concrete were analyzed by linear polarization resistance (LPR) and electrochemical impedance spectroscopy (EIS). The results show that two kinds of migrating corrosion inhibitors can restrain corrosion of reinforcing steel, the corrosion efficiency of ZX was less more than MCI. Migrating corrosion inhibitor not only can improve carbon steel impedance, also can improve concrete resistant. Key words: migrating corrosion inhibitor;Cl-;reinforcing steel;linear polarization resistance;electrochemical impedance spectroscopy
Sorptivity as a Measure of Salt Frost Scaling Resistance of Air-Entrained Concrete
Authors: Liu Zhi Chao , Hansen Will
Published: October 2014

Salt frost scaling is the progressive deterioration of the concrete surface associated with freezing and thawing in the presence of a salt solution. Its major mechanism has been confirmed to be cryogenic suction that promotes continuous ice growth in the surface region. In this paper, salt frost scaling of different air-entrained concretes is investigated, alone with the room-temperature sorptivity measurement. A clear correlation is found between the two properties, which is supported by a theoretical analysis on the sorptivity. These findings explain why HPC of low w/b ratio and associated low capillary porosity has much improved scaling resistance. Similar benefits are obtained for regular w/b ratio concrete containing high cementitious replacement level of slag cement.
Experimental Research on Effect of Curing Methods on the Strength and Resistance to Chloride Ion Permeability of Concrete in Simulated Arid and Large Diurnal Temperature Variation Climates
Authors: Yu Ben Tian , Wang Qi Cai , Du Ying Dong , Xie Chao
Published: October 2014

Curing techniques and curing conditions have crucial effects to the strength and durability of concrete. The objective of this experimental study is to examine the strength and resistance to chloride ion permeability of high performance concrete under various curing methods in different simulated arid and large diurnal temperature variation climates. Laboratory experiments were conducted to investigate the strength and electric flux when different curing methods were used. Three curing methods and three simulated climates were applied to concrete specimens. The results show that the difference of measured experiment data are not significant under standard curing (SC), moisture insulation curing (MIC) and thermal and moisture insulation curing (TMIC) in an arid climate. However, the compressive strength and resistance to chloride ion permeability are worse under MIC and TMIC compared with SC in an arid and large diurnal temperature variation due to frost heaving and thermal stress. Moreover, compressive strength and resistance to chloride ion permeability decrease significantly when the large diurnal temperature variation increases and the lowest temperature reduces. The insulation material can effectively reduce concrete temperature variation between near surface and core region. Therefore, TMIC is a better curing method than MIC in an arid and large diurnal temperature variation climate.
HPC Subjected to High Temperature: A Study on Intrinsic and Mechanical Damage
Authors: Rossino Chiara , Lo Monte Francesco , Cangiano Stefano , Felicetti Roberto , Gambarova Pietro G.
Published: October 2014

Heat-exposed High-Performance Concrete (HPC) has been the subject of relatively few studies focused on the relationship between the chemo-physical processes occurring in concrete constituents (microscopic level) and concrete mechanical properties (macroscopic level). In order to investigate the correlation between the intrinsic damage and the mechanical damage induced by heat exposure, eleven concrete mixes have been investigated, differing for: compressive strength (fcm,cube ≥ 45, 70, 95 MPa), aggregate type, fiber type (polymeric and metallic) and fiber content. The microstructural and mechanical characterization was carried out on concrete specimens before and after being exposed to 105, 250, 500 and 750°C. The results show that using different experimental techniques at the microstructural level allows to monitor the development of microcracks, whose size is similar to that of macropores. This behavior at the nano, micro-level is reflected by the post-peak branch of the stress-strain curve at the macro-level. This extensive investigation allows to understand concrete mechanical decay due to heating on the basis of microstructural observations, paving the way to mix optimization for high temperature and fire.
Effect of Fiber on Mechanical Properties and Fire Resistance of C100 Ultra High Strength Concrete
Authors: Huo Liang , Lin Xi Qiang , Li Guo You , Zhang Tao
Published: October 2014

It used conventional techniques and materials prepared high strength fiber reinforced concrete whose strength class is above C100 and it studied the effect of fiber content on the mechanical properties and elastic modulus. It also studied the fire resistance of fiber reinforced concrete. Results suggest that the strength of 28d concrete is above 100MPa and the highest strength is 126.4MPa. Under the same ratio conditions, the greater the volume content of steel fiber concrete flexural strength, the splitting tensile strength is higher. The steel fiber volume only affect elastic modulus of concrete little. When it heats to 300 °C, the no fiber concrete comminuted burst while the fiber concrete does not damaged at elevated temperatures up to 300 °C and continue to heat up, the crushing damage occurs at about 460 °C. Has not been damaged concrete specimens at 300 °C, the quality have emerged about 3% decline, while the compressive strength increased by 35%-52%, the highest strength reached 180.3MPa.
Reliability Analysis of High-Strength Concrete Columns during a Fire
Authors: Xiao Jian Zhuang , Xie Qing Hai , Hou Yi Zhao , Li Zhi Wei
Published: October 2014

A reliability analysis was conducted on high-strength concrete (HSC) columns during a fire. The influences of fire’s randomness and explosive spalling of concrete were investigated. The fire resistance for axial loading capacity of HSC columns was in terms of steel yield strength and concrete compressive strength with considering the effect of elevated temperatures. The load random variables included dead load and sustained live load. The JC method was applied to calculate the reliability index of the fire resistance of axially loaded HSC columns. It was found that the randomness of fire and explosive spalling of concrete had a significant influence on reliability of HSC columns.
Modeling of Moisture Distribution Evolution in High-Performance Concrete under Fire Exposure
Authors: Zhao Jie , Peng Gai Fei
Published: October 2014

High-performance concrete (HPC) will undergo severe damage under fire conditions. It is well known that vapor pressure induced by high temperatures plays an important role in the damaging process. Therefore, the determination of the moisture distribution evolution in concrete is essential to the damage analysis of heated HPC. This paper presents a numerical method for the prediction of the moisture distribution evolution in HPC under fire conditions. In the method, the vapor pressure and the moisture transport induced by the vapor pressure gradient are analyzed. The effect of the thermal decomposition on the moisture distribution and the effects of the slippage flow and the water saturation degree on the permeability are considered. The proposed method is applied to the moisture distribution analysis of a concrete cube with 90% initial moisture content under fire conditions and can be further used for the analysis of the thermal damage of heated HPC.
Utilization of Circulating Fluidized Bed Combustion (CFBC) Fly Ash and Coal-Fired Fly Ash in Portland Cement
Authors: Chi Mao Chieh , Huang Ran , Wu Te Hsien , Fou Toun Chun
Published: October 2014

Circulating fluidized bed combustion (CFBC) fly ash is a promising admixture for construction and building materials due to its pozzolanic activity and self-cementitious property. In this study, CFBC fly ash and coal-fired fly ash were used in Portland cement to investigate the pozzolanic and cementitious characteristics of CFBC fly ash and the properties of cement-based composites. Tests show that CFBC fly ash has the potential instead of cementing materials and as an alternative of pozzolan. In fresh specimens, the initial setting time of mortars increases with the increasing amount of cement replacement by CFBC fly ash and coal-fire fly ash. In harden specimens, adding CFBC fly ash to replace OPC reduces the compressive strength. Meanwhile, CFBC fly ash would results in a higher length change when adding over 30%. Based on the results, the amount of CFBC fly ash replacement cement was recommended to be limited below 20%.
Effects of Fly Ash and Granular Blast-Furnace Slag on Development Rate of Strength of Concrete
Authors: Cai Ji Wei , Yan Si Jia , Wei Gong Lei , Wang Lu , Zhou Jin Jin
Published: October 2014

Fly ash (FA) and granular blast-furnace slag (GBFS) are usual mineral admixtures to conventional concrete, and their contents substituted for Portland cement definitely affect development rate of strength of concrete. C30 and C60 concrete samples with FA and/or GBFS were prepared to study the influence of substitution content of the mineral admixtures on 3 d, 7 d and 28 d strength. The results reveal that the development rate of strength in period from 3 d to 7 d gets slow with increasing content of mineral admixtures except for concrete with only GBFS less than 20%. In the case of substituting FA as the only mineral admixture for part of cement, the development rate of strength of C30 concrete in period from 7 d to 28 d keeps roughly constant even that of C60 concrete increases. When substituting mineral admixtures in the presence of GBFS for cement within experimental range, the development rate of strength in period from 7 d to 28 d gets fast with increasing substitution content. The enhancing effect of combining FA and GBFS occurs in period from 7 d to 28 d for both C30 and C60 concretes (FA+GBFS≤40%), even occurs in period from 3 d to 7 d for C60 concrete. Based on 7 d strength and the development rate, 28 d strength of concrete can be predicted accurately.
Multifunctional Use of Self-Compacting Concrete as A Fundamental Material in Dam Construction: Upper Gotvand Dam
Authors: Zabihollah Zadeh Ali , Zafari Behzad , Yaminpour Masoud
Published: October 2014

Contemporary knowledge of SCC concretes, that brought about of worthy endeavors of numerous researcher and engineers have come in handy now.Taking advantage of such material makes compound construction more efficient, easier and less expensive. Upper Gotvand , a 180 meters height rock fill dam located southwestern Iran have several affiliated projects using SCC concrete for their high reinforced or hard to access segments such as bottom outlet structure, pressure tunnel blocks, concrete coating for penstock steel lining, upper and lower bends, powerhouse structures and etc. Particular structural peculiarities for each individual projects have been detected as well and SCC-related conclusions were made. To satisfy essential needs in order to make this concrete more ideal we are about to study mix design components to select the most consistent ingredients. Different available cements, third generation admixtures, and aggregate sources interaction were explored to elicit the most optimized mix design, native to region. In this article, accomplished quality control tests have been introduced. Test results have led to satisfactory mix manipulation and to ensure optimized attributes for required practical applications.
It was revealed among Gotvand SCC ingredients, Binders and fines are the most ruling components, capable of governing practical traits. River aggregates are highly beneficial and Gelenium51P acts consistently with Ilam cement. Assigned Q.C. tests have led us to favorite mix named, NA45.
Because of higher lateral pressure of fresh SCC than ordinary concrete, it was allocated to heading and upper lifts of walls. More water proof forms and more support requirement as well as longer setting time were concluded as relative constraints of SCC at practice.
Study on Mechanical Properties of Microbead Modified Super Sulfate Cement Concrete
Authors: Gao Yu Xin , Xiang Jia Yu , Wang Jun , Yu Bao Ying
Published: October 2014

The microbead modified super sulfate cement (SSC) was employed to prepare C60~C80 concrete, this work emphasis on mechanical properties and micro-mechanism, besides, the service behaviors of fresh concrete was tested. The SSC concrete mechanical properties influenced by particles size of microbead, slag and gypsum were discussed. Mechanisms of mechanical properties changes were elaborated from micro, meso and macro scales, mechanical model was established and relevant rules of mechanical properties development were obtained. Experiment results show that compressive strength increased with the largerer specific surface area of microbead, slag powder and gypsum. There was a promoting effect for SSC concrete hydration reaction by appropriate dosage (10%~20%) of microbead, which had prominent interstitial effect and system with excellent gradation, and fresh concrete workability was significantly improved. The compressive strength—curing ages model of high strength SSC concrete was established by half value intensity index, which coincide well with measured values. Key words: super sulphated cement concrete, microbead, mechanical properties, mechanical model, specific surface area
Evolution from High Strength Concrete to High Performance Concrete
Authors: Bilek Vlastimil , Tomalová Vladimíra , Hájek Petr , Fiala Ctislav
Published: October 2014

High strength concrete for the production of concrete railway sleepers was designed more than 20 years ago. The compressive strength of the concrete was very high from the start, but flexure strengths showed some irregular development - a decrease in time. Later, also a significant decrease of fracture properties was recorded. Microcracking was found to be the reason for this; therefore some modifications were performed to avoid this happening (especially the reduction of the maximum size of aggregates from 22 mm to 16 mm or 11 mm). Some problems concerning frost resistance of the concrete with a slag addition were reduced by applying ternary binders. All of the results are discussed from the point of view of a long-term observation of the strengths and fracture properties ́ development during the time period of 5 years or even more.
Effect of Octyl-Triethoxysilane Emulsion on Protection of Concrete
Authors: Zhang Xin Yuan , Li Shao Chun , Zhao Tie Jun , Jin Zu Quan
Published: October 2014

In this study, octyl-triethoxysilane emulsion was prepared using octyl-triethoxysilane monomer. The protective effect of the silane monomer and emulsion was investigated on the concrete with different water to cement ratios (0.4 and 0.5). The results showed that octyl-triethoxysilane emulsion displayed efficient protection of concrete. Octyl-triethoxysilane emulsion acquired excellent penetration depth (> 3.7 mm), the water absorption coefficient was reduced by 83.4%, and the chloride ion diffusion coefficient was only 1.8 × 10−12 m2 s−1, reduced by 71.3%. The emulsion also showed good resistance to carbonization and freezing-thawing. The carbonation depth of concrete was reduced by 42%, while the silane monomer has little effect on carbonization. Good protection performance was obtained in the freezing-thawing cycle tests. The relative dynamic elastic modulus was increased by 27%; the mass loss was reduced by 49% after 300 cycles. The protective effect of silane emulsion was also related with the water cement ratio of concrete and the test method. Silane monomer had good waterproof effect and chloride resistance, but poor resistance to carbonization and freezing-thawing. Silane emulsion was a better choice for concrete protection, for it displayed lower rate of volatilization, insignificant toxicity, and better retainment of the active ingredient.
Study on Experiments of Matekaolin in Relation to Alkali-Silica Reaction
Authors: Zhou Hong Yi , Li Fu Hai , Chen Si Yin , Zhao Xiao Gang , Li Gu Hua
Published: October 2014

The influence of the content of matekaolin powder and fly ash in cement on controlling ASR was evaluated using Accelerated Mortar Bar Test (AMBT). Replacing cement with matekaolin powder to the extent of 5%,10%,15%,20%,25%,and with fly ash to the extent of 10%,20%,30%,35%,40%, 45% respectively. The result show that matekaolin powder and fly ash both can control Alkali-aggregate activity but to different degrees. Small amount of metakaolin powder exerts significant influence, whereas only when the proportion of fly ash is up to 35%, can it control ASR effectively. The effect and mechanism of the control of the extension of glass aggregate activity was studied by means of SEM analysis.
Anti-Seismic Behavior of Hybrid Masonry – RC Structure
Authors: Li Jing , Wang Dong , Ouyang Yi , Hou Zhao Rong
Published: October 2014

According to current engineering practice, Confined Masonry (CM) buildings are weak in earthquake resistance and difficult in post-quake restoration. A new form of structure, i.e. Hybrid Masonry – Reinforced Concrete Structure (HMRCS), is investigated. By slightly increasing the sizes and reinforcement ratios of the RC members, i.e. beams and columns, which normally only act as confinement in a CM structure, now play an essential role in resisting the gravity load in HMRCS, while the masonry wall mainly resists the lateral earthquake load. To investigate the seismic-resistant behavior, pseudo-static tests on two full-scale HMRCS specimens were conducted, and the measured hysteretic curves were analyzed. Finite Element (FE) simulation was performed to verify the working mechanism and seismic response of the HMRCS specimens. The lateral displacement ductility factor obtained from the experimental results can fully satisfy the seismic requirement of structures. Therefore, HMRCS is reliable if its RC frame members and masonry walls are designed properly. Furthermore, the feasibility of using FE software to study the proposed HMRCS has been validated by comparing the experimental and simulation results.
Low Cost Ultra-High Performance Fiber Reinforced Concrete (UHPFRC) with Flash Metakaolin
Authors: Nguyen Amanjean E. , Vidal T.
Published: October 2014

Ultra-High Performance Fiber Reinforced Concrete (UHPFRC) presents remarkable mechanical and durability properties. Concretes can be considered as UHPFRC when compressive strength and direct tensile strength reach respectively reach 150 MPa and at 7 MPa at 28 days [1]. The UHPFRC matrix is generally composed by a high amount of cement and silica fume as binder, steel fibers, very low Water/Binder (W/B) ratio and high rang water reducer. Special heat treatment is often required in order to achieve compressive strengths over 150-200 MPa. This work focuses on the development of low cost UHPFRC with less energy in production process in order to widespread its use. To reach this objective, some mix criteria have been set up: use of local materials, substitution of silica fume by less expensive and more available flash metakaolin, reduced cement content, without heat treatment. Four UHPFRC mixtures have been fixed. The reference one incorporates silica fume. In the second one, metakaolin substitutes weight by weight silica fume. Two other mixtures have been designed using a wet packing method [2] and a metakaolin water absorption test [3], in order to optimize the metakaolin/cement mass ratio and to reduce cement content. Workability and mechanical tests have been carried out. Results show that the weight by weight substitution of silica fume by flash metakaolin leads to a slight reduction (about 5%) of strengths but a more important reduction of cost (about 10% of UHPFRC material cost per m3). The optimization of metakaolin/cement ratio allows reaching equivalent performances of silica fume reference mix and reducing cement content without significant strengths decrease.
Purification and Size Control of AlN Powder for AlN Single Crystal Growth
Authors: Lee Kang Huk , Jeong Seong Min , Kwon Woo Teck , Kim Soo Ryong , Shin Dong Geun , Kim Hyung Sun , Kim Y.
Published: October 2014

AlN single crystal can be grown by physical vapor transport (PVT) method. The purity and particle size of the source material are important factors for single crystal growth to obtain good quality of AlN single crystal. The aim of this study was purification of AlN powder and growth of its particle size through thermocyclic treatment. The initial particle size was about 1.0 μm and the purity was 98.4% containing 1.6% oxygen and metallic impurities such as Fe, Sn, Ca, Na and Mg etc. which were analyzed based on KSL1612. For purification of AlN powder, it was performed using a thermocycle process with various thermocyclic numbers. After the thermocycle treatment, it is able to obtain large particle size AlN powder as much as 30μm and purity was increased to 99.6% based on chemical analysis.
Synthesis and Characterization of Ag/Graphene Nanocomposites by Solid-Liquid Sonochemical Reactions
Authors: Mochizuki Tomofumi , Hayashi Yamato , Fukushima Jun , Takizawa Hirotsugu
Published: October 2014

In this study, Graphite Oxide (GO) and Ag/Graphene nanocomposites were synthesized by solid-liquid sonochemical reactions easily and briefly. GO was synthesized by means of Hummers method using sonication or stirring. From XRD patterns and FT-IR spectra, chemical and physical effects of ultrasound promoted the oxidation of Graphite. Ag/graphene nanocomposites were synthesized from GO and silver oxide by sonication. UV-vis spectra showed the peaks of Graphene oxide and Ag nanoparticle plasmon resonance absorption. EDX images and electron diffraction patterns confirmed Ag nanoparticles were decorated on Graphene sheets by ultrasound. Using sonication, GO and Ag/Graphene nanocomposites could be synthesized easily in short time.