bluuebunny/crossref_metadata_2025 huggingface dataset:
Three-Stage Permanent Deformation Behavior of Subgrade Soils
Authors: Fang Rui , Gao Hui , Bian Xiang Qin
Published: October 2011

The development of the permanent deformation of subgrade soils under repeated load tests may consists of three stages, namely the primary, secondary and tertiary stages, but the existing models can not describe this behavior very well, so a new model is required to be developed. Based on the creep equation of the soil under static load, a mechanistic model is developed to describe the development of the permanent deformation of the soil under repeated load tests. Triaxial repeated load tests are conducted for silty soils and results show that, under some conditions, the development of the permanent deformation of silty clay consists of three stages and the number of load repetitions corresponding to the initiation of the tertiary stage is 330,0000. The new model is used to fit the test results and the comparison of test results and fitting results prove that this model can describe all three stages of permanent deformation.
The Temperature Field of Dispersion Nuclear Fuel Elements
Authors: Jiang Xin , Liu Xiao Hang
Published: October 2011

A representative volume element is chosen to act as the research object to analyze the temperature field of the dispersion fuel elements. The thermal analysis is carried out for the thermal behaviors using FEM. The results indicate that with the volume fraction and the heat generation rate of the fuel particles increasing, the temperature and the gradient of the temperature in the matrix and the cladding increases markedly.
Investigation of Existing Situation and Study on Energy-Saving Potential of Rural Residential Buildings in Pearl River Delta
Authors: Li Ting Ting , Zhao Li Hua
Published: October 2011

The rapid development of rural economy has led the massive construction of rural dwellings, while the energy consumption is increasing correspondingly. A field study was carried out in local nine villages of Pearl River Delta, aims to look into actual conditions of rural residential buildings and explore the energy-saving potential, a detailed questionnaire survey was conducted as well to investigate the construction of rural dwellings and the influencing factors in design. The results of this investigation, which focused on dwellings built by residents, revealed that the built form of dwellings is generally Low-rise house, the average storey height ranges from 3.6 to 4 meters. The primary building envelope is 200 cm clay brick wall construction, and not insulated flat roofing, moreover, the high energy consumption of increasing multistorey dwellings has drawn attention.
Risk Consequence Assessment of Existing Bridges Using Fuzzy Based Analytic Hierarchy Process
Authors: Deng Jun , Li Jian , Fang Xiao Yue
Published: October 2011

The assessment of the risk probability and risk consequence of existing long-span bridges has become a focus in both research and engineering applications. In this paper, a process to assess the risk consequence of existing long-span bridges is developed. The analytic hierarchy process was combined with the fuzzy synthesis. In accordance with the features of existing long-span bridges, risk consequences are classified and the model of the risk consequence is simulated. A bridge as the example is evaluated by this process and the results show that the risk consequence of the bridge is negligible. Combining the risk probability and risk consequence gives the comprehensive risk of this bridge is negligible.
Cradle-to-Gate Analysis of Materials Used in Historic and Modern Housing in China
Authors: Ding Grace K C , Ge Janet X , Phillips Peter
Published: October 2011

Climate change and energy efficiency are some of the most pressing issues facing China today. With its economic growth since the economic reforms in 1978 the government has struggled to contain environmental damage and social strife related to the economy’s rapid transformation. With the rapid growth in population and urbanization the demand for housings escalated and thus existing houses are under threat of being demolished to make way for new construction. However there was a strong debate that existing houses should be maintained and upgraded instead of demolishing for new development as improvements to energy and water efficiency of existing homes can significantly reduce greenhouse gas emissions and decrease utility bills. This paper aims at reviewing the importance of existing houses and their environmental significance in conservation as opposed to demolition. This paper presents and discusses the preliminary results for the first two stages of a research project undertaken at the University of Technology Sydney to investigate environmental performance of historic housings in Xiao He Zhi Jie in Hangzhou, China.
Experimental Research on Seismic Behavior of RC Column with Different Concrete under Horizontal Low Cyclic Loading
Authors: Wu Jing , Wang Fa Zhou , Li Yue , Yang Wen , Hu Shu Guang
Published: October 2011

On the premise of maintaining certain vertical bearing capacity, the frame structure dissipates seismic energy by elastic-plastic deformation in elastic-plastic stage of earthquake action. Using lightweight concrete in structure not only can reduce the its dead weight, decrease the earthquake power; also meet the concrete strength, stiffness and elastic modulus requirements of important structure, so as to improve its energy dissipation capacity. This paper researched the effect of concrete materials, including or such as C60 high strength Lightweight concrete (HSLC), high strength concrete (HSC) and high strength Light weight aggregate concrete (HSLAC), on the seismic behavior of RC column under horizontal low cyclic loading, respectively and the match relationship between concrete and steel reinforcement cage was analyzed.
Analysis of Three-Dimensional Excavation Slope Stability Subjected to In Situ Stress Based on Strength Reduction FEM
Authors: Wang Jun Qi
Published: October 2011

Slope usually lies in an initial stress field, especially in complex three-dimensional stress conditions. When horizontal stress is larger than vertical stress or the two horizontal stresses are not the same, the horizontal in-situ stress has significant effect on the excavation slope stability. To investigate the effects of the original in-situ stresses, the strength reduction method is used to analyze three-dimensional excavation slope, and Mohr-Coulomb yield rule is adopted, the failure criterion based on analysis convergence is suggested. First, the horizontal stress is uniform based on the gravity load, when lateral pressure coefficient increases, the safety factor decreases, and the plastic zones develop from slope to foot foundation. Then the condition of lateral pressure coefficient change is analyzed, slope direction pressure coefficient increases, plastic zone on the slope bottom increases, the safety factor decreases remarkably. Using the same method to analyze that of the lateral pressure coefficient on the slope face direction increases, the slope FS increases little holding the K2 unchanged with the K1 adding. The results show that the slope direction pressure coefficient has more effects on the safety coefficient than that of the axis.
Experimental Study on a Beam-to-Column Connection Using Shape Memory Alloy
Authors: Ma Hong Wei , Yam Michael C. H
Published: October 2011

For ductile beam-to-column connectiosn in steel frame, beam local buckling is difficult and very costly to repair in any post-disaster reconstruction. Shape memory alloys (SMAs) in their austenite states have the ability to recover their original shape after experiencing large deformations. Steel connections retrofitted using SMAs can be endowed with intelligent characteristics. This paper investigates extended end-plate connections using long shank SMA bolts. The SMA connection is designed using a new methodology of avoiding beam local buckling and adopting the strong end-plate. The connection deformations are supposed to concentrate on the SMA bolts. In order to study the seismic behaviour of the connections, quasi-static tests were conducted on both the SMA connection specimens. The test results indicate that the connection can show high deformation capacity with the maximum interstory drift angles beyond 0.02 rad. However, the beam was remained elastic during test and the deformations of the SMA connection were recoverable upon unloading. The load-drift hysteresis loops are flag-shaped for the SMA connection. This indicates that the connection has moderate energy dissipating capacity.
Research on the Conception, Mechanism and Design Method of Steel Structure Dam
Authors: Wei Qun , Zhang Guo Xin
Published: October 2011

Steel structure dam, as a newborn dam type in hydropower engineering field, is proposed in this paper. The conception, operating mechanism, bar concection and the design and calculation methods are introduced. The characteristics of the steel braced frame that overall force and stability are fully utilized, and also the steel properties, such as high strength, high tenacity and high wearing. As a new technique and method, it opens up a new way for the application of rich steel resources in the hydropower engineering, which shows a good development prospects.
R/S Analysis for Stress Evolution in Shaft Lining and Fracture Prediction Method
Authors: Zhao Guang Si , Zhou Guo Qing , Zhao Xiao Dong , Wei Ya Zhi , Li Long Ji
Published: October 2011

The rupture disasters occurred in more than 110 shafts in Eastern China in recent 23 years, and that caused a significant economic loss. The stress evolution in shaft is investigated by R/S method based on in-situ measured additional strain caused by ground drainage in present study. The results indicated that the R/S method predicts the variation of additional strain well. The Hurst index for additional strain lies in the range of 0.5~1 and the sequence is random walk with positive skew. In other hand, the positive skew of stress in shaft is less evident at the depth of 120 m. The research proposes guidance for prevention similar shaft rupture disaster is provided for similar shaft.
The Influence of Stochastic Imperfection Field on the Bearing Capacity of Hyperbolic Cooling Towers
Authors: Zhao Hai , Xu Ya Zhou , Bai Guo Liang
Published: October 2011

The uncontrollable factors such as construction errors, material inhomogeneity, etc. will inevitably lead to a certain initial imperfections. It is generally known that the stochastic initial imperfection of the structure is an important factor for affecting structural stability and bearing capacity. Since these imperfections are random in nature, this paper proposes the method mainly based on the standard orthogonal basis to expand the stochastic field, taking into account the decomposition of the stochastic initial imperfections related to structures, which is projected in the buckling mode orthogonal basis. In the end, the article by the stability analysis example shows that this method can use less random variables effectively describing the original stochastic imperfection field, and efficiently search for the most unfavorable initial imperfection distribution form in order to ensure the imperfection sensitivity structures have a higher reliability, so it can be applied to large-scale engineering structure stochastic imperfection analysis.
Influencing Factors of Lanzhou’s Urban Green System Planning in China
Authors: Zhang Xiao Juan
Published: October 2011

By reviewing Lanzhou urban green system planning development since 1949, this paper analyses the guiding principles, the dominant function and layout structure of urban green system planning construction in different time. Based on above analysis, these factors that influencing Lanzhou green system planning are researched. By using these results, the intrinsic movement and rule of urban green system planning construction are proposed. It gives a good case for reference of Lanzhou green system planning practice.
Support Uplift Analysis and Monitoring of a Steel-Concrete Composite Curved Pedestrian Bridge in the Course of Construction
Authors: Xiang Chang Sheng , Fu Chung C. , Li Hui , Zhao Geng Wen , Ahmed Mohamed
Published: October 2011

It is essential to avoid or reduce construction errors when field connecting curved steel girders together with diaphragms. Construction errors usually change the mechanical system, create unexpected internal forces and residual stresses in steel girders or diaphragms, which cause construction difficulty of follow-up work and create safety issues. In this article, as a case in point, two inner supports of a curved two- steel girder pedestrian bridge were uplifted when two steel girders being tied together by the diaphragms. To continue upper concrete deck work, a temporarily added dead load at both ends of girder was applied. Through field investigation and based on mechanical reasoning, we detected the main cause of the uplift. Moreover, we built a finite element model to simulate the procedure of construction step by step and stresses of every step were obtained. In the meantime, displacements of the supports were monitored by laser measurement system while the added dead load was released. When the whole bridge construction was completed, a field loading test was taken, displacements and strains were measured. Compared the calculation result with the test data, we drew a conclusion that the installation error produced very low residual stress, and there is no effect to the structural safety under the full design load.
A Study on the Simulation System of Landscape Lighting and the Luminance Perception
Authors: Sun Li Ye , Sun Li Xin , Tang Shu Min , Hai Hong
Published: October 2011

Considering the characteristics of vision in different luminance levels and the errors of the visual angle restituting, this research obtains a series of simulant scenes and the quantity relations between the luminance of actual scenes and reappearance scenes in the low luminance and weak contrast environment. Finally, carrying the subjective evaluation of these scenes, it obtains the scope of luminance and the quantification relations among these stimulus by statistical analysis. This paper provides theoretical basis for scene simulation and evaluation, and obtain quantitative suggestions for corresponding standards. It has important theory significance and the practical value for landscape lighting planning and design.
Numerical Analysis on Concrete Elastic-Plastic Constitutive under Different Restraints
Authors: Wang Hong , Jin Chong , Yuan Hong , Xia Xiao Zhou
Published: October 2011

The fitting curve given by least square method is applied in numerical analyzing. The results from semi-unrestrained and completely restricted modeling show convex deformation and damage on oblique section clearly. Advanced virtual experiment illustrates the differences between loading with displacement and pressure, due to the phenomenon that pressing by force will cause deformation on top surface but displacing load wouldn’t. The fitting idea by orthogonal base function will provide a widely road for studying the constitute law of concrete material. Otherwise, the progress of solving nonlinear function is discussed for designing new numerical analyzing tool, and the frame of programming based on nonlinear method is obtained
Mechanical Behavior of the Shear Studs on Composite Deck of Steel Arch Bridge
Authors: He Zu Lin , Zhong Wei Ping , Zhang Wan Jun , Wu Chong , Qin Fei , Yang Guo Tao
Published: October 2011

Shear studs are critical important connectors in steel and concrete composite structures, and they will subjected to longitudinal shear force and transverse shear force, and as well as the tensile force under the applied loads. The mechanical behaviors of the studs are very complicated. In this paper, the spatial finite element model of Xinshiji Bridge, a steel truss arch bridge, was established, and the mechanical responses of the studs under various load cased were analyzed. The calculation results show that the shear forces of the studs under the dead loads are very small due to the structural characteristics of the bridge and the construction sequence of the bridge decks. Thermal effects, especially the effect due to temperature difference, are the key factors for the design of the studs in region near the ends of the bridge decks.
Effect of Lap Gap on the Frictional Performance of Shear-Type Friction Damper
Authors: Zhang Peng Bo , Yu Zhi Xiang , Sun Yu Ping , Zhao Shi Chun
Published: October 2011

The shear-type friction damper using aluminum alloy as the friction material were designed and tested under cyclical loading to investigate the effect of the lap gap to the frictional performance. The test results indicated that the dampers with a lap gap could also absorb energy stably with the same hysteretic behavior as a general friction damper; the frictional force of the shear-type friction damper depended not only upon the bolts tension by the high-strength bolts that clamped the sliding steel plate but also strongly upon the scale of lap gap. The lap gap changed in a scale of 0.12mm only, the average sliding force has four times increase at a lower level of bolt tension, and a double effect to increasing sliding force at the higher level of bolt tension.
On Bracing Strut Failure in the Framed Arch Bridge and a New Method for its Restoring & Reinforcing
Authors: Yao Liang Yun , Chen Shen
Published: October 2011

A typical failure of the light framed arch bridge under frequently super loads is studied, by means of establishing the EFM solid models for the whole bridge and the bracing strut to analyze the failure mechanism of the bracing strut in the Pingzhai framed arch bridge from the mechanical behavior and some defect of the structure itself, simulating the deterioration of reinforced concrete in wet joint of the bracing strut. Based on the mechanics, a new practical method for restoring and reinforcing the above bracing strut is presented also, which has been proved to be successful in the engineering practice.
Study on Envelop Influence for Building Performance
Authors: Zong De Xin , Chen Jun
Published: October 2011

Envelop is an important component of building. Well designing on envelop makes great sense to promoting climate adaptability for the building, improving building comfort and driving forward energy conservation. This paper starts with the design principle of adaption to climate, variability, economy, localization and integration, then carries on the elaboration to design strategies on wall, glass curtain wall, window sunshade, balcony and corridor, roof and other parts; lastly a typical office building model is established to simulate and analyze envelop performance.
Environmental Impact Comparison of Different Structure Systems Based on Life Cycle Assessment Methodology
Authors: Xiong Hai Bei , Zhang Chao , Yao Jiang Tao , Zhao Yang
Published: October 2011

Life cycle assessment (LCA) has become an international recognized method to estimate the environmental impacts of a building during its life. A building’s environmental impacts can be divided into two parts－impacts in the service stage and impacts in other stages of its life cycle. Other stages comprise material acquisition stage, constructing stage and final disposal stage. In life cycle except service stage, the LCA analysis was made on a timber structure teaching building using Athena software Eco-calculator. Then the teaching building is assumed to be redesigned adopting the structure of RC-frame and steel frame respectively. And the LCA analysis was made on the two assumed buildings too. By comparing the results, the conclusion can be drawn that timber buildings have lower environmental impact indexes compared with that of RC-frame and about the same with that of steel structure. The aboard usage of the timber structure instead of RC-frame structure can result in good environment performance. In service stage, if a sensible thermal insulation scheme is also considered, a great amount of energy will be saved, and the environmental impact of a building can be made minimum.
Calculation Domain and Boundary Conditions for Push-Pull Ventilation
Authors: Zhou Yu , Wang Yi
Published: October 2011

CFD simulation is a useful tool for studying. However, in reality there are often complex, unsteady air flow patterns and large geometry domain and complex boundary conditions which are very difficult to totally take into consideration in the simulations. So sometimes we made the calculation domain not the same with geometry domain and simplified the boundary conditions. In this paper, five cases were made to study the calculation domain and boundary conditions for push-pull ventilation. According to the analyses and calculations the walls with windows and door closed setting for wall boundary conditions were not correct. On that basis cracks added, and the boundary conditions were pressure-inlet, and the pressure was zero. The calculation domain was reduced, the result was some different: the tendency was the same, but the difference of specific point values was some big. The new boundaries of the reduce calculation domain were set for pressure-inlet, and the pressure was zero. Under this condition, the cracks could be simplified to wall boundary conditions.
Effective Energy Saving Research on the Air Exchange Rate of Residential Buildings in Guangzhou Based on the Software DeST-h
Authors: Du Wei Wei , Qin Cui Cui , Zhao Li Hua
Published: October 2011

Reasonable determination of indoor ventilation rates are the main content of residential ventilation designs, and can save consumption by air conditioners. Firstly, the energy saving potential of ventilation cooling technology in Guangzhou is analyzed in this paper. The cooling load of a residential building in Guangzhou with different air exchange rates is simulated by the DeST-h after indoor heating quantity of different rooms is set. The energy saving rate is analyzed, the functional relation between energy saving rate of ventilation and air exchange rate is obtained using the linear-regression analysis method. After a comprehensive consideration of various factors, including variation of energy efficiency, room volume, air outlet size, and that the maximum air exchange rates of different rooms are fixed.
Test Study of Pore Water Pressure during Dynamic Compaction at the Subgrade of Highway in the Yellow River Flood Area
Authors: Yao Kai , Yao Zhan Yong , Song Xiu Guang , Shang Qing Sen
Published: October 2011

The Yellow River flood area mainly consisted of silt and silty clay. Water level observing holes and pore water pressure gauges were embedded in the test section. The observation results showed that: The pore water pressure of 3m and 5m grew slowly at the beginning. With the increase of ramming strike and the total ramming strike energy, the fourth hit pore water pressure mutated and then grew slowly. The pore water pressure of 7m and 9m grew slowly all the time. Because of the well point dewatering, the excess pore water pressure dissipated very soon. 70~75% of the excess pore water pressure of the first pass dissipated 3 hours after ramming strike, then the excess pore water pressure dissipated slowly. The excess pore water pressure of 3m and 5m grew significantly, so the effective reinforcing depth of dynamic compaction was 5m.
The Study of Vent Form of Double-Skin Facade Based on CFD
Authors: Zhou Chuan Hui , Xue Na
Published: October 2011

In this paper, taking a building in Wuhan as a case, the CFD method is used to simulate the air flow field and temperature field of respiration double-skin facade,and by analysis, we know how the position and size of air inlet and air outlet can influence the thermal performance , and their area ratio2:3 is suggested with staggered arrangement. Meanwhile, according to the simulation results of the three models, we come to the conclusion that the special structures of double-skin facade can form natural convection heat transfer, take away the heat in channels and achieve the goal of energy conservation and consumption reduction.
Numerical Analysis of Lab Ventilation on Double Gaseous Polluted Sources
Authors: Jiang Da Hua , Li An Gui , Shi Fa En , Wang Zhi Hua
Published: October 2011

This article uses CFD to study the efficiency of ventilation and pollution discharge of double polluted sources in the lab, and investigate the effect of air exhaust outlet location and air supply velocity on the performance of side ventilation. Using non-dimensional analysis method to analyze change of temperature,velocity with room height, the change of temperature efficiency and pollutants emission efficiency with the air supply velocity. The results show that the efficiencies of temperature and pollutants emission are the highest when h/H=0.175 and v=0.4m/s.
Experiment Research on Air Flow Rate Measurement Using Tracer Gas Method
Authors: Zeng Xian Yang , Chi Zuo He , Zheng Ming Guang , Sun Gong Gang , Zhang Guang Xue , Wang Jin Qing
Published: October 2011

Experiment research on the air flow rate measurement using tracer gas method in a 300mm internal diameter and 90° elbow duct are presented, which CO and air are selected as tracer gas and gas stream. Results show that the relative errors between the flow rate measured by tracer gas method and turbine flowmeter are varied in the range of -2.15%~1.69% when the injection point is upstream of the elbow on 7D~13D (D is the internal diameter of the duct), and the sampling point is downstream of the elbow on 10D~14D. The further distances of the injection point and sampling point are apart, the less relative errors of the gas flow rate measured by tracer gas method and turbine flowmeter are made. The injection flow rate of tracer gas should be matched with the gas flow rate in the duct. It is a simple and effective method that gas flowmeter online calibration with tracer gas method on the large diameter industrial gas pipeline transportation.
Interfacial Electrochemistry of Bond Cement and Tubular Steel
Authors: Ren Cheng Qiang , Gao Lei , Li Li , Guo Ming Lin
Published: October 2011

The stability of interface between bond cement and tubular steel is very important to the integrality of oil and gas wells. However, research on the degradation of the interface in aggressive solution is absent to date. This work devotes to discover the relationship of electrochemical parameters and interfacial development during early stage of corrosion by analyzing the electrochemical results. Dielectric spectroscopy obviously describes the stability change of passive film of steel, and Bode plot supports the structure change of cement. The early stage of immersion in aggressive solution is dominated by competition of hydratation and corrosion.
Asphalt Concrete Road Surface Summer Temperature Prediction Based on Radiant Balance Theory
Authors: Yang Qin
Published: October 2011

By using energy balance method and considering the balance among solar short wave radiation, atmospheric and pavement surface long wave radiations, latent heat fluxes and sensible heat fluxes, a prediction model for AC road surface temperature is established. The pavement temperature and meteorological observation data of Ningbo city (from 2009 July 15 to 2009 August 13) have been used to validation of the model. The results show that a high accuracy was existed between the measured and calculated temperature in the clear days. when S (daily sunshine-ratio)>60%, the maximum absolute error of calculated daily maximum pavement temperature is less than 3 °C, and the multi-day mean absolute error is 1.5 °C. But in cloudy or rainy days, the model’s accuracy will be lower than the clear days.
Numerical Simulation on Fire Smoke Flow with Jet Fans in an Underground Garage
Authors: Wang Ying , Shi Bi Ming , Mu Chao Min
Published: October 2011

With the aim of evaluating capabilities of a ventilation system with jet fans to control fire smoke in an underground garage, we carried out a set of FDS simulation. According to the results, temperature and soot density of fire has reduced within an acceptable range. We believe that the ventilation system based on the jet fans has indeed controlled fire smoke effectively, thereby we have enough time for safety rescue.
The Working Procedure Design and Industrialization Experiment on Sludge Incineration Generate Electric Power
Authors: Cheng Jian Guang , Shi Long Qing
Published: October 2011

The purpose of this paper is to analyze the sludge characteristics of the Qingdao Ni Buwan Sewage Treatment Plant and introduces the sludge disposal technique in recent years and designs an incineration working procedure on power station. The method used in our study is known as directly heat dry-cure incineration technique for generate electric power in Qingdao Jiaonan Power Co., Ltd. We have carried out several sets of experiments to test the validity of incineration generate electric power. The results of the experiment indicate that this incineration program is practicable, resolves the sludge disposal problem in Qingdao Ni Buwan Sewage Treatment Plant and has effect and profit in economic , social and environment.
Study on Treatment of Wastewater from the Production of PolyTHF with Iron-Carbon Micro-Electrolysis-Biological Method
Authors: Zuo Yan , Ai Sheng Shu , Ren Qing Kai , Liu Jing , Bian De Yun
Published: October 2011

Abstract: the process condition of combined treatment of wastewater produced from the polytetrahydrofuran (PolyTHF) with iron-carbon micro-electrolysis-biological method was studied, and the results showed that with Fe-C proportion of 1:1, pH value of about 3.0 and contact time of 30min, the wastewater CODcr removal rate could reach higher than 75% when 0.15g/ml of Fe-C was input, thus the biodegradability of wastewater was greatly improved. After treatment, the wastewater was treated with biological method with a water outlet COD less than 100mg/L, conforming to the first-level quality of national stipulation about comprehensive discharge standard of sewage.
Effects of the Addition Amount of Silica Aerogels on Mechanical Properties and Microstructure of Insulating Materials
Authors: Ma Lin , Wang Jia Bin , Xin Gui Yan , She Qi Yao
Published: October 2011

Insulating materials were prepared by microsilica, silica aerogels and quartz fibers as raw materials, water glass as binder, and molded by the semi-dry method. In this paper, the effects of the addtion amount of silica aerogels on mechanical properties and microstructure of insulating materials were studied. X-ray diffraction (XRD) was used to characterize the phase composition and scanning electron microscope (SEM) was used to characterize the microstructure of the materials. The results show that when the silica aerogels content was at 40%, the material had the best properties in present study of true porosity of 45.9%, flexural strength of 5.0MPa and compressive strength of 37.9MPa, respectively.
The Effect of Organic Fibers on Crack Resistance of Concrete and Applicable for Secondary Lining
Authors: Cao Qing Yu , Sun Wei , Guo Li Ping
Published: October 2011

In this paper, concrete incorporated organic fibers, i.e., polyvinyl alcohol fiber (PVA fiber), polypropylene fiber (PP fiber), cellulose fiber (UF fiber), polyethylene fiber (PETF) was produced. The properties measured included strength and crack resistance performance of the concrete. The effect of organic fibers on the crack resistance properties was investigated. Test results indicated that the organic fibers of different types could reduce the size and amount of crack source; organic fibers provided better enhancement for shrinkage resistance of concrete; Cellulose fiber concrete applied for secondary lining under the Ⅲ wall rock, both work performance and strength index satisfy the design demand, and concrete surface cannot detect crack after 280 days.
Photodegradation of Dyeing Wastewater by High Photocatalytic Activity TiO2 under UV and Visible-Light Irradiation
Authors: Niu Jin Fen , Yao Bing Hua , Wei Jia
Published: October 2011

High photocatalytic activity TiO2 photocatalysts were prepared using titanium(IV) sulphate as the precursor by liquid-phase precipitation method. X-ray diffraction and TEM were employed to characterize the morphology, structure of the photocatalysts. Photocatalysic activity of TiO2 prepared by this method was investigated using photocatalytic degradation of methyl red (MR) under UV and visible-light (VL) irradiation as the model reaction. The results indicated that the highest catalytic activity TiO2 catalyst was prepared under 700°C calcination for 4h. The optimum decoloration rate of simulated dyeing wastewater for MR reached to 95% and 98% after UV and visible-light illuminating for 30 min and 140min respectively.
Comparison of Three Constitutive Models for the Analysis of Laminar Magnetorheological Fluid Flows
Authors: Jin Fang Yin , Liu Rong , Wang Lin Xiang
Published: October 2011

In the current paper, three different constitutive models are employed for the analysis of laminar MRF (MagnetoRheological Fluid) flows between two parallel plates. The capability of a recently constructed non-convex constitutive model is compared with those of widely used Bingham model and Herschel-Bulkley model. The comparison among simulated flow velocity distributions and shear stress - shear strain rate characteristics based on different models is presented. It is shown that the non-convex consitutive model outperformance the other two models.
The Practical Step-by-Step Procedure of High-Order Dynamic Response Analysis for General Damped System
Authors: Yu Rui Fang , Zhou Xi Yuan , Yuan Mei Qiao
Published: October 2011

For general damped linear systems with multiple eigenvalues, this study provides a practical step-by-step procedure of the high-order dynamic response analysis. The method derived in this study has clear physical concepts and is easily to be understood and mastered by engineering designers. Moreover, a numerical example is used to analyze the correctness and the effectiveness of the new method by comparing the calculation results with the theory solution.
Bidirectional Moving Force Identification on an Orthotropic Rectangular Plate
Authors: Zhang Wei , Yu Ling
Published: October 2011

Based on the modal superposition and dynamic programming theory, a method is proposed to identify bidirectional moving forces from orthotropic plate bridge responses in time domain. The bridge deck is modeled as an orthotropic plate and the moving vehicle loads are modeled as two groups of axle loads moving cross the bridge deck in two opposite directions. The equation of motion is formulated in state space and the resulting damped least-square identification problem is solved using the dynamic programming method with regularization on the solution. Some numerical simulations show that the proposed method is effective, accurate and suitable for the bidirectional moving vehicle load identification. Some parameter effects of measurement noise and of eccentricity of moving loads on the identification accuracy are discussed as well.
Peak Traffic Prediction Using Nonparametric Approaches
Authors: Zhang Yang
Published: October 2011

How to accurately predict peak traffic is difficult for various forecasting models. In this paper, least squares support vector machines (LS-SVMs) are investigated to solve such a practical problem. It is the first time to apply the technique and analyze the forecast performance in the domain. For comparison purpose, other two non-parametric predictors are selected because of their effectiveness proved in past research. Having good generalization ability and guaranteeing global minima, LS-SVMs perform better than the others. Providing sufficient improvement in stability and robustness reveals that the approach is practically promising.
A New Health Monitoring System for Cable-Stayed Bridges I: Consist and Contents
Authors: Luo Ling , Du Bai Song , Luo Hong
Published: October 2011

Based on the purpose of the bridge health monitoring, a new health monitoring system, including hardware and software part, is proposed for cable-stayed bridges in detail. The system is categorized as five sub-systems covering sensor system, data acquisition system, data analysis system, simulation analysis system, and warning system. Many monitoring parameters including environment wind, temperature field, humidity field, strain, deflection, cable forces, and traffic can be obtained by those five sub-systems. The purpose and monitoring content of each parameter are illustrated in the paper, and moreover, the method of the layout of the measuring points is put forward.
Baseline Correction of Digital Strong-Motion Data-Examples from the 2008 Wenchuan, China, Earthquake
Authors: Li Heng , Wang Dun , Cai Yong Jian , Wu Jian Chao , Liu Gang
Published: October 2011

This paper analyzes key noises within digital strong-motion acceleration recording that can result in baseline offset, and according to their specific position provide a baseline correction scheme for preserving the long-period ground motion. This correction method is then applied to the digital acceleration records from the 2008 Wenchuan earthquake, and also, when compared with GPS data (including some high frequency of 1Hz GPS data), it is shown that this method can well restore displacement of ground motion, including permanent displacement which is the main concern of seismologists. Furthermore, compared with other methods that aim to restore the ground displacement, it has much greater stability.
A Standing Wave-Duct System for Acoustical Property Prediction of Multi-Layered Noise Control Materials
Authors: Wang Yan Song , Zhang Tao , Chen Na , Lei Jie
Published: October 2011

Based on a hybrid transfer-matrix method, a new standing wave-duct system with four microphones for acoustical property prediction of multi-layered noise control materials is developed in this paper. In this system, the two-load method (TLM) and two-cavity method (TCM) are used for computing the transfer matrix of each material sample. The transfer matrices saved in a database in the system hardisk may be selected for predicting both the absorption ratio and transmission loss of a multi-layered treatment of materials. Verification results suggest that the newly designed standing wave-duct system is effective for acoustical prediction of multilayer material configurations.
Numerical Simulation on Combined Deformation of Tip-Loaded Cantilever Beam with Particle Flow Code
Authors: Xiong Yi Bo , Wang Chun Ming , Peng Lu
Published: October 2011

In order to calculate the combined deformations of an Euler-Bernoulli cantilever beam subjected to bending moment, twisting moment, transverse load and axial load, particle flow code in 3 dimensions (PFC3D) is used with parallel bonds model. The computed deformations, including transverse deflections, rotations about axis, maximum normal and shear stresses, were compared with the analytical beam-theory solution in terms of axial tension, axial compression and none axial load, respectively. Between computed results and analytical beam-theory solution, the error bands are greater than 99.7% at the beam tip, while the error of the transverse deflection of the whole beam is less than 0.6%. So, the PFC3D is able to precisely simulate the combined deformation of cantilever beam, and this work has special reference to engineering calculations and designs when PFC is applied to model the mechanical behaviors of continuum materials.
Highway Bridge Load-Bearing Capacity Assessment Under Chinese and British Methodologies
Authors: Selman Mudhafer H.
Published: October 2011

The purpose of assessment of structures is to check their adequacy for specific loading levels and to identify those bridges that have an unacceptable risk of failure, either in part or complete collapse, under extreme circumstances of loading and material condition [1]. In this study, a comparison was made between new Chinese bridge load-bearing capacity assessment method and The British Highway Agency method. Load-bearing capacity assessment results were generated for bridges super structure and analyzed for moment and shear load effect. Also the study included a comparison of the main component of load-bearing capacity calculation, factored live load, factored dead load, and factored capacity. The comparison shows that the British Method produced lower moment and shear bridges carrying capacity factor than Chinese Method.
Acoustic Radiated Calculation of a Finite Cylindrical Shell and Interface Design of the Programs
Authors: Qiu Fei Fei , Liu Xiao Wei , Shi Huan Wen , Wang Yong
Published: October 2011

Based upon the vibratory equation and sound radiation impedance of a cylindrical shell, the sound field distribution of a finite cylindrical shell simply-supported at two infinite rigid cylindrical shells were resolved with considering the structural loss. An interface containing some buttons connected with all the programs was designed by using Matlab, and their data were all stored in a file. It has been shown that the sound radiation power of the cylindrical shell decreases and the radiation efficiency increases with increasing of structural damping loss factors; when the frequency of the driving force is low, the sound field shapes “∞” directivity pattern; When the frequency of the driving force grows higher the sound directivity pattern becomes complex due to superposition of axial modes and circumferential modes; Only when the radiation of the end plates is much weaker than the cylindrical shell the analytical results of the shell simply-supported at two infinite rigid cylindrical shells can be utilized to illustrate the sound radiation by a finite cylindrical shell with two end plates.
The Study on Flow Simulation Based on Virtual Reality
Authors: Wen Cen
Published: October 2011

The method in this paper the efficiency and reusability of the flow simulation algorithm be significantly improved. We put forward a specific example to demonstrate the application of this method to groundwater simulation. Numerical simulation results can let researchers in VR walked into the model, and to help decision, the investigation, forecast and the management of natural resources.
Research on Hydrocarbon Emission Regularity of Passenger Car
Authors: Qiao Xiang Ming , Xu An
Published: October 2011

To analyse and research the idle hydrocarbon emission regularity of passenger car gasoline engine, based on large sample detected data of different type cars, parameter estimation and hypothesis test are carried on by statistical tools and neans, and the optimum distribution parameters of idle hydrocarbon emission of different type engines are also got. Then the optimum distribution models of these engines are established. The calculating result shows that the maximum error between model calculating and sample detecting certification rates is only 0.526 8%, and the established models have very high calculating precision and practical value. On the other hand, the research also shows that the inspect and maintenance program should be strengthen in order to control vehicle emission pollution effectively.
Acoustic Emission Characteristics of Rock Failure under Uniaxial Loading
Authors: Xie Tao , Jiang Qing Hui , Chen Rui , Zhang Wei
Published: October 2011

With RMT-150C rock testing machine and AEWIN E1.86 DISP acoustic emission system applied, the acoustic emission test was accomplished with two kinds of rock samples including marble and granite under uniaxial compression. Cyclic loading and continuous loading were used through the experiment, and the mechanical performance and acoustic emission (AE) characteristics were obtained during the process of rock progressive failure. Details related to the relationship between amount of AE and stress-strain was given in this paper. A comparison between marble and granite was made as well following the general AE law, on the basis of which, the failure mechanism of rock mass was investigated. Finally, some conclusions can be summarized as follows:(1) AE activity features are different with stress state variation in rock failure process;(2) loading patterns make a direct impact on the failure process thereby affecting AE activities;(3)AE activities are various basing on the different types of rocks, structures and failure modes.
Centrifuge Modeling and Numerical Simulation of Air Sparging Process
Authors: Hu Li Ming , Lee Heng Zhen , Wang Jian , Du Jian Ting
Published: October 2011

Air sparging (AS) is one of the in-situ groundwater remediation techniques for remediating volatile organic compounds (VOCs) contaminated soil, and the knowledge of air flow features is essential in designing air sparging system for soil remediation. The centrifuge modeling technique was employed to simulate the in-situ conditions and to investigate air follow characteristics during air sparging by using glass beads as soils. Several centrifugal modeling tests were performed under various g-levels. According to the test results, the zone of influence (ZOI) during air sparging is in a truncated-cone shape under various g-levels, which can be expressed by the lateral expansion around the air injection point and the cone angle between the vertical axis and the boundary of ZOI. A 2D numerical model is used to model the air movement during air sparging process. The ZOI and the water saturation distribution were obtained. The results agree well with the centrifuge test data, which indicates the two phase flow model is reasonable to simulate the air sparging process. It was also shown that air compressibility and buoyant force have a significant influence on the extent of ZOI and should be adequately considered. Hence centrifuge modeling and numerical simulation can be used as a design tool for in-situ air sparging system
Face Stability Analysis of Rectangular Tunnels Driven by a Pressurized Shield
Authors: Tu Xiao Ming , Yang Yu You , Wang Gui He
Published: October 2011

With the development and utilization of underground space, some new tunnel forms are emerging, such as the rectangular tunnel, double tunnels, treble tunnels and so on. The aim of this paper is to determine the collapse face pressure of a rectangular tunnel driven by a pressurized shield. The calculation is based on the upper-bound method of the limit analysis theory. A translational kinematically admissible failure mechanism consists a sequence of truncated rigid cones are considered for the calculation schemes. The numerical results obtained by the calculation are presented.
Carbonation of Fly Ash Concrete and Micro-Hardness Analysis
Authors: Tu Liu Qing , Xu Wen Bing , Chen Wei
Published: October 2011

The effects of carbonation age, fly ash content in the binder and the water to binder ratios on the carbonation depth of fly ash concrete is investigated and the micromechanical properties of the hardened paste and the inter facial transition zone is analyzed with the micro-hardness method. The experimental results show that replacing Portland cement in concrete with fly ash increases the carbonation rate at early ages, while the late age carbonation rate is lowered. Micromechanical analysis shows that the carbonation reaction increases the micro-hardness of the paste and the compactness of the ITZ. For the relative low replacement levels, the width of the ITZ is reduced if the concrete is carbonated.