bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Al-10RE Modification on Microstructure and Mechanical Properties of ZL203 Aluminum Alloy
Authors: Shi De Quan , Gao Gui Li , Gao Zhi Wei , Wang Yan Liu , Wang Xu Dong
Published: October 2011

The influence of Al-10RE addition, holding time and holding temperature on the microstructures and mechanical properties of ZL203 aluminum alloy has been studied respectively through using the optical microscope and the universal mechanical testing machine. The experimental results lead to the following conclusions. When Al-10RE addition is 1.0%-1.5%, the holding time is 15 minutes and the holding temperature is 730°C-750°C, the microstructure of Zl203 is perfect. With the increase of Al-10RE addition, the mechanical properties including tensile strength, elongation rate and hardness gradually increase. When the Al-10RE addition is 1.0%-1.5%, the mechanical properties reaches maximum. When the Al-10RE addition is above 1.5%, the mechanical properties decrease with the increase of Al-10RE addition.
The Corrosion Fatigue Life Research of Shot Peening Aluminum Alloy
Authors: Li Song , Cui You , Lv Sheng Li , Zhang Wei , Tong Xiao Yan
Published: October 2011

The corrosion is one kind of major damage mechanisms of airplane structure and is also one of the primary causes resulting in flight failure and disaster .The aim of this paper is to analyze the effect of corrosion time on denudation depth, mass loss and the total depth of corrosion damage. Meanwhile, the three parameters have significant influence on residual fatigue life of aluminum alloy, the residual fatigue life of the aluminum alloy is of great difference between shot peening and without shot peening aluminum alloy. Then residual fatigue life tests are carried on Instron 8801 for the shot peening and without shot peening aluminum alloy. Based on contrast analysis of the experimental results, valuable conclusions are obtained: with the increase of the denudation depth, mass loss and the total depth of corrosion damage, fatigue life reduce continuously respectively; Fatigue life decreases rapidly when the denudation depth is in the range of 0.12～0.17mm.
Near Infrared Quantum Cutting for Solar Cells in CeF3:Yb3+ Nanophosphors
Authors: Li Su Wen
Published: October 2011

The CeF3 nanophosphors with Yb3+ concentrations from 0 to 8% had been prepared by hydrothermal method and characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscopy (TEM). Their photoluminescence properties including excitation spectra, Uv-visibe and near infrared (NIR) emission spectra and fluorescence dynamics were studied. In the CeF3: Yb3+ nanophosphors an intensity infrared emission originated from Yb3+2F5/2 - 2F7/2 transition at 900-1050 nm matching to the energy of Si band gap of Si-based solar cells was observed under the excitation of 5d level of Ce3+. The lifetime of Ce3+ decreases and the quantum efficiency (QE) increases with increasing Yb3+ concentration.
The Influence of Temperature and Oxidation Time on the Preparation of Graphite Oxide
Authors: Huang Qiao , Sun Hong Juan , Peng Tong Jiang
Published: October 2011

Graphite oxide samples with different oxidation levels were prepared by the oxidation of natural flake graphite based on a modified Hummers method, using different reaction temperatures and oxidation times followed by ultrasonication then centrifugation to obtain the corresponding graphene oxide nanosheet suspensions. The samples were characterized by XRD and AFM. The results show that the oxidation level of graphite oxide samples can be increased by increasing either the reaction temperature or the oxidation time. Well-dispersed suspensions of the graphite oxide samples can be formed in alkaline solution after ultrasonication, especially for samples with higher oxidation levels. A number of coarse particles are observed in the suspensions, particularly those derived from graphite oxide samples with lower oxidation levels, due to the lower degree of exfoliation in these samples, which is influenced by the oxidation level. Rapid sedimentation of these coarse particles can be achieved by high-speed centrifugation, yielding homogenous suspensions of graphite oxide comprising a mass of monolayer graphene oxide nanosheets with lateral dimensions of several hundred nanometers to several micrometers and thickness of ~1.0–1.4 nm.
The New Progress of Nickel Sulfide Synthesis
Authors: Zhang Ya Hui , Wang Qing
Published: October 2011

Nickel sulfide has been the subject of considerable interest because of its potential applications in many fields. In this paper, the synthesis of nickel sulfide nanostructures is described. The Morphologies of as prepared nickel sulfide nanostructures are summarized. And the applications and prospects of nickel sulfide in this field also are analyzed.
Effect of Aging Treatment on the Thermal Stability and Properties of Cu-10Fe-3Ag In Situ Composites
Authors: Li Yong , Liu Rui Qing , Xu Fang
Published: October 2011

The effects of aging treatment on the microstructure and mechanical properties of Cu-10Fe-3Ag in-situ composite were investigated. And the mechanism of Ag element was analyzed during aging treatment. The results show that: presence of Ag can accelerate γ-Fe precipitation from in the Cu matrix, but also reduces the thermal stability of Fe fibers. As the aging temperature increasing, the hardness and conductivity of Cu-10Fe-3Ag in-situ composite increase at first and then decrease. The conductivity of Cu-10Fe-3Ag in-situ composite can reach 58.4% IACS when aging for 6h at 475 °C. The Fractures of the alloy are all ductile rupture and the dimples are smaller with the aging temperature increasing.
Numerical Simulations of Drilling Mud Invasion into the Marine Gas Hydrate-Bearing Sediments
Authors: Ning Fu Long , Yu Yi Bing , Jiang Guo Sheng , Wu Xiang , Zhang Ke Ni , Zhang Ling , Liu Li
Published: October 2011

When drilling through the oceanic gas hydrate-bearing sediments, the water-based mud under overbalanced drilling condition will invade into the borehole sediments. The invasion behavior can influence the hydrate stability, wellbore stability and well logging evaluation. In this work, we performed the numerical simulations to study the effects of density (i.e., corresponding pressure), temperature and salinity of mud on the mud invasion and hydrate stability around borehole. The results show that the mud invasion will promote greatly the hydrate dissociation near wellbore sediments if the temperature of mud is higher than that of hydrate stability. Under certain conditions, the higher mud density, temperature and salinity, the greater degree of mud invasion and heat transfer, and the more hydrate dissociation. The gas produced from hydrate dissociation can reform hydrates again in the sediments, and even the hydrate saturation is higher than that in situ sediments due to the displacing effect of the mud invasion, which forms a high-saturation hydrate girdle band around the borehole.
First Principles Investigation of Phase Stability of LaNi3 and LaMg2Ni9
Authors: Gao Wei , Niu Jian Gang
Published: October 2011

First-principles calculations were performed to study the relative stabilities of LaNi3 and LaMg2Ni9. The calculated results show that LaMg2Ni9 has the higher stability than LaNi3. The preferential stability of LaMg2Ni9 was analyzed in both structural and electronic views.
Effect of Mineral Admixtures on Chloride Ions Content in Concrete Repair Materials
Authors: He Zhi Min , Liu Jun Zhe , Wang Tian Hong
Published: October 2011

The amount of total chloride ions in concrete used as repair materials were measured under immersion conditions. The corresponding major influencing factors under natural diffusion condition were also investigated by different testing methods. The results indicated that the amount of total chloride ion significantly varies with the water to binder ratio when the water to binder ratio varies from 0.3 to 0.55. Compared with pure cement concrete, the precipitation of chloride ions in the concrete with fly ash or ground granular blast furnace slag (GGBFS) under sigle dimensions immersion was much lower. The concrete with double adding of 10% FA and 20% GGBFS acheives the lowest value of total chloride ions content.
Genetic Analysis and Repair of Cracks in Prestressed Concrete Box Girders during Precast Period
Authors: Liu Shi Ming , Zhao Shun Bo
Published: October 2011

During the initial period of precast prestressed concrete box girders in a bridge, some cracks appeared in five box girders. The paper describes the crack states including location, elongation, space, width and depth. The geneses of the cracks are analyzed considering the concrete proportion, environmental condition and construction procedure. Four of them were permitted to be used after mending of these cracks and another one was abandoned directly. After the preventing measurement was adopted, no cracks appeared in the follow-up precast box girders. The experience can be as reference for the similar construction works.
Supercritical Carbon Dioxide Heat Exchanger Tube Numerical Simulation and Analysis
Authors: Yang Jie , Lv Jing , Yang Da Zhang , Liu Kang , Zhang Song Bo , Lu Hui Xia
Published: October 2011

In this paper, the three straight casing tubes and the double helix casing tubes were modeled using the Gambit software. And the fluid flowing in tubes was simulated by Fluent software. According to the simulation results, with the field synergy principle, two casing tubes’ flow and temperature distribution of carbon dioxide and water have been analyzed. Simulation data show that the double helix casing tubes is better than the three straight casing tubes on heat transfer and synergy. Lay the good foundation for design optimization and efficiency of heat exchanger of carbon dioxide heat pump system.
Reliability Assessment of 4.2 MW Single Shaft Typhoon Gas Fired Turbine Power Generation Station (2003 – 2008)
Authors: Adegboye B.A. , Ekundayo K.R.
Published: October 2011

The paper assesses the reliability performance of the 4.2 MW, Single Shaft Typhoon Gas Fired Turbine Power Generation Station at Beta Glass Plc (Guinea Plant), Agbara, Ogun State, Nigeria. The monthly outage data of the station for the period of 68 months (May, 2003 to December, 2008) were collected and used to compute the yearly reliability indices of the generating unit. The unit availability was found to be low, especially in 2007 and 2008. The station recorded highest number of fuel gas supply failure throughout this period. The core engine failures were frequent and repairs were not promptly effected which made the unit to operate below its rated capacity. The high forced outages recorded are indications of unreliable performance. Appropriate recommendations were proposed.
Investigating the Quality of Power Supply to a Large Commercial Installation
Authors: Adegboye B.A. , Mele M.G.
Published: October 2011

The paper investigates the quality of power supply to the Corporate Headquarters of the Power Holding Company of Nigeria (PHCN), PLC, Maitama, Abuja. This was facilitated by the measurements conducted using the harmonitor 3000 power analyzer on the secondary terminals of the two (2) 1000kVA, 11kV three-phase transformers serving the Company. The data on the network consisting of voltages, currents, power factor and harmonic distortion were acquired by the Harmonitor. Analysis of these data shows that there is significantly high variation between the minimum and the maximum voltage and that the phase loads are unbalanced. There is low power factor and the total harmonic distortions (THD) on the phases and neutral are high. The causes of the poor quality of power supply were identified and recommendations proposed taking into cognizance the complexity and sensitivity of the equipment in the network.
Computer Simulation of Lightning Strikes to a Horizontally Buried Earth-Electrode: A Parametric Analysis
Authors: Ubeku E.U. , Ike S.A.
Published: October 2011

Earthing systems made basically from earth electrodes need to be effectively designed to meet the increasing demand on safety. The aim of this paper is to use computer simulation to analyze the transient response of a horizontally buried earth electrode and how this response is influenced by factors like the energization type, the soil parameters, the depth of burial and the earth electrode geometry. The model used is the transmission line theory with a general application of the telegraphy equations which are solved numerically using the finite difference time domain scheme while the per unit length parameters were computed from a well known integral expression using the moment’s method. The results of the parametric analysis are validated by comparison with those found in literature.
An Adaptive Approach to Improve the Accuracy of Packet Pre-Filtering
Authors: Jesudoss Sofiya , Jesudoss Auxeeliya , Sulaiman Ashraph
Published: October 2011

The current day networks are under deliberate, continuous and premeditated attacks such as Hacker attacks, DoS attacks, IP Address Spoofing, Phishing, Sniffer attacks etc. The Network Intrusion Detection Systems (NIDS) proved to be reliable in parrying most of the issues and challenges faced by the corporate network security systems. But, the NID systems fall short in providing a completely fool-proof network security environment. False negatives and false positives proved to be considerable bottle necks in securing the networks from the attacks. This paper deals with the introduction of a software approach for the packet pre-filtering to ease security threats and the introduction of Network Behavior Analysis to enhance the security of the network. The Network Behavior Analysis helps the system to ease the burdens to the network and security of the network by the false positives. The NIDS compares all the incoming packets with the pre-defined rules or signatures to find suspicious patterns. The pre-filtering approach used in this paper is a result of the observation that very rarely an incoming packet matches the signatures or the IDS rules. During the pre-filtering step, a small portion of the packet is compared against the predefined signatures for any suspicious patterns and the initial pre-filtering match is considered for a full match. For time efficiency, this strategy is compared to more optimistic schemes that allow reassignment of flows between threads, and evaluated using several network packet traces.
Numerical Investigation of Thermo-Mechanical Behaviour of Ball Grid Array Solder Joint at High Temperature Excursion
Authors: Amalu E.H. , Ekere N.N. , Bhatti R.S. , Mallik S. , Takyi G. , Ibhadode Akii Okonigbon Akaehomen
Published: October 2011

The solder joints of surface mount components (SMCs) experience thermal degradation culminating in creep and plastic shear strain deformation when subjected to cyclic temperature load over time. Degradation at the joints is due to thermal stress induced by the incompatible, differential and nonlinear expansion mismatch of the different bonded materials in the assembly. The stress magnitude influences the strain behaviour. Plastic strain response of solder joint is critical at the materials interface at the lower part of the joint due to the occurrence of wider variation in the coefficient of thermal expansion of the bonded materials and this may lead to static structural failure. The life expectancy of electronic components reduces exponentially as the operating temperature increases thus making reliability a key concern for electronic systems operating at high temperatures and in harsh environments. This paper reports on the numerical investigation of thermo-mechanical response of a critical BGA joint especially the character of plastic deformation of SnPb solder used in forming the joint as well as the joint’s high temperature reliability. The analysis uses a 3-D models to predict the effect of the transient thermal load on the static structural integrity of a single BGA joint. In this study, the base diameter of solder ball (interface between the PCB, copper pad and the solder) experienced higher damage than the top diameter interconnects. The paper provides a simplified methodology to study the reliability of BGA solder joint at high temperatures excursion.
A Study of the Extraction of Pectin from Dried Lemon Peels
Authors: Lerotholi L. , Carsky M. , Ikhu-Omoregbe Daniel Imwansi Ogiem
Published: October 2011

Pectin was extracted from dried lemon peels using acid hydrolysis. Five process variables/factors were chosen for investigation; the extraction temperature, extraction time, pH, size of the peels and the peel to water mass ratio. Three response variables were monitored; the Yield (% Yield), Degree of Esterification (% DE) and Galacturonic Acid content (% GA). A duplicated 25 factorial design was conducted on dried peels. The extraction temperature, time, pH and size of the peel were found to be the most significant variables affecting the pectin yield. The most significant variable affecting the % GA was found to be the extraction time and the % DE was most significantly affected by the pH as well as the extraction temperature. A duplicated 24 design (peel size excluded as a process variable) on fresh wet peels was conducted in order to compare the results attained to those of dried peel extraction. Drying the peel therefore increased the greatest pectin yield attained, it had no drastic effect on the % GA, but it reduced the % DE of the pectin extract. A 24 design was also performed on wet peels that had been stored at atmospheric conditions for two days. The results were compared to those found from fresh wet peel extraction, in order to depict the need for drying the peel.
Determination of Operational Parameters of a Single Cylinder Two Stroke Engine Run on Jatropha Biodiesel
Authors: Duvuna G.A. , Wara A. A.
Published: October 2011

The utilization of jatropha oil in a small capacity laboratory diesel engine was investigated. The Jatropha biodiesel was obtained from National Research Institute for Chemical Technology, Zaria - Nigeria. The biodiesel was within the EN, BIS and Brazil specification for biodiesel. The tested blends were 20/80%, 30/70%, 40/60% and 50/50%. Each blend was tested on a short term trial of one hour. 20/80% jatropha oil/diesel blend addition gave the maximum brake power and thermal efficiency. The exhaust gas temperatures of the jatropha oil/diesel blends were lower than that of diesel signifying lower heat loss. The percentage heat losses were lower when operated on higher jatropha oil/diesel blends. For economy of fuel, 20/80% gave specific fuel consumption values when compared to other jatropha oil/diesel blends at all engine speeds. Higher volumetric efficiencies were obtained for lower engine speeds of jatropha oil/diesel blends. Air/fuel ratio shows a decreasing trend with increase in jatropha oil content in jatropha oil/diesel blends. There was no reaction of the jatropha oil/diesel blends with engine parts as there was no engine starting problems, wear out of components or breakdown. No long term assessment, emission characteristics or endurance tests including breakdown of jatropha oil biodiesel were carried out. The research found that 20/80% blend of jatropha oil/diesel blend gave the best performance amongst all blends It is recommended that 20/80% jatropha oil/diesel blend should be used to supplement fossil fuel.
Feasibility Study of Low Cost Concrete Products as an Appropriate Alternative Construction Material in the Rwandan Construction Industry
Authors: Dedek Kazawadi Papias , Claude Mutuyimana Alphonse Marie , Kumaran G. Senthil
Published: October 2011

This study was carried out as an investigation into concrete products as an appropriate alternative for plastic, rubble stone and steel in the construction of domestic water tanks, door and window frames in the Rwandan construction industry. This project is an innovation aimed at adding value to the available resources of materials and personnel to expose untapped opportunities that are beneficial to the Rwandan community and the world in general through conservation of the environment and creation of employment. In a similar sense, this effort responds to the result of too much consumption of wood products in this rapidly growing infrastructure sector and calls for alternatives such as concrete in construction of door and window frames .In order to answer the research objectives, the researchers opted to observe, carry out demonstrations/ modeling, views of the end users of the product especially for water tanks. Data gathered from this research instrument were then computed and interpreted. Along with primary data, the researchers also made use of secondary resources in the form of published articles and literatures to support the survey results. Curved interlocking concrete blocks are affordable, environment friendly, labour intensive and use locally available materials, adoptable by both the rural and urban settings, uses local materials and uses local labour hence providing employment. At the end, these products were compared with conventional materials for their costs and maintenance. The results show promise as new construction material suitable for use in Rwanda. However, use of concrete for door and window frames is new to Rwanda and should further be investigated for adoptability.
Assessment of the Operations of Stone Crushers in Artisanal and Small Scale Granite Quarries
Authors: Melodi M.M.
Published: October 2011

Estimation of the respective productivities of men and women stone crushers in Artisanal and Small Scale Granite Quarries was carried out by collecting data from sample sites and conducting statistical treatment of collected data. An analysis of the results shows that the productivities of men and women stone crushers are 1.1 and 0.6 tonnes per day. Based on these results, a rating scale of output and required manpower in Artisanal Granite quarries was developed using interval and nominal rating methods.
Multi-Item Multi-Period Dynamic Capacity-Constrained Lot-Sizing Model with Parallel Machines and Fuzzy Demand
Authors: Ogunwolu Ladi , Alli O.A. , Onyedikam Chidi , Sosimi A. A.
Published: October 2011

Multi-item, multi-period production systems are prevalent in traditional production and distribution settings. A dynamic lot size production scheduling model (DLSPM) for multi-Production/inventory item multi-period production system with parallel machines is proposed in this paper. A mathematical framework that extends the DLSPM to multi-Production/inventory item-multi-period production planning constrained by storage space was built. The criteria of DLSPM explore optimal production schedule with the constraints of inventory, backlogs, production and demand to minimize the total inventory costs over finite planning horizon. Demand analogous to a typical production environment considered includes dynamic deterministic and fuzzy demand. The model was tested with both deterministic and fuzzy demand spread over ten years, for five equal planning periods, with a two Production/inventory item and two parallel machine test bed. From the various demand types, several iterations (sub problems) were generated and optimality condition was then verified. To capture the imprecision that is often inherent in the estimated future demand, demand was specified by fuzzy numbers and modeled using the triangular membership function distribution. Centre of gravity defuzzification scheme was used within finite intervals to obtain defuzzified demand. Tora Operations Research software was used to run the model using a test problem. Computational results vindicate the robustness and flexibility of the approach based on the quality of the solutions obtained.
Measurement of Gamma Radiation in Automobile Mechanic Workshops in an Area of Benin City, Nigeria
Authors: Nworgu O.D. , Osahon O.D. , Obinyan F.E.
Published: October 2011

Environmental radiation measurement was carried out in several automobile mechanic workshops within Ugbowo area of Benin-City, Edo State, Nigeria. A Digilert 50 Nuclear Radiation monitor was used to ascertain the level of radiation to which these workers are daily exposed. The study revealed that the average annual effective dose rate from these sites is approximately 0.40 mSv/yr which is lower than the value of 1.0 mSv/yr averaged over five consecutive years according to the dose limit placed by the Basic Safety Standards (BSS) SCHEDULE II and the International Commission on Radiological Protection (ICRP) REPORT 60. However, the external background ionizing radiation exposure within the sites investigated varied between 0.1272 and 0.01411 mR/hr with an average of 0.01314 ± 0.000658 mR/hr in the locality which is relatively higher than the standard background radiation of 0.011 mR/hr recommended by the US Nuclear Radiation Commission. This level of background radiation seems to suggest that there is a possibility of the existence of radio nuclides within the area.
Integrated Solid Waste Management System – A Case Study of Solid Waste Source Sorting Alternative in a Tertiary Institution in Nigeria
Authors: Igbinomwanhia D.I. , Alao N.J.
Published: October 2011

In most developing countries, solid waste components are generally commingled. Sorting of solid waste is one of the most important activities in the material recovering process of the integrated solid waste management system. If solid waste is sorted, about 30% of the work is done. Several methods exist for sorting comingled solid waste. The work presented in this paper involved the study of solid waste source sorting alternatives in Nigerian Universities. A site-specific study was carried out to characterize the solid waste generated in the University of Benin. Alternative concepts for sorting of solid waste were considered and evaluated. Source sorting was then selected for this study. The study revealed that about 14.56% of biodegradables, 42.26% of plastics, 39.62% of paper waste and 3.56% of metal waste are generated in the office and classroom areas of University of Benin. The study also showed that there is poor attitude to solid waste issues as the maximum cooperation realized on source sorting of solid waste was only about 50% for the waste-bin designated for plastic. The results obtained from the study also indicated that intensive sensitization of the generators on the benefits of source sorting is required for effective source sorting.
Determination of the Efficiency of Aerated Lagoon in Biological Treatment of Human Waste (Faeces)
Authors: Omotoso T. , Folorunso O.P.
Published: October 2011

Pilot scale “Waste Stabilization pond” was evaluated for treating high quality waste water using aerobic process. The method involved the measure of the molecular oxygen utilized during a specified incubation period for the biochemical degradation of organic matter and oxygen used to oxidize inorganic material. Operation of the pond involved engineering construction to reduce the risk of soil and groundwater contamination. Calibration of the model using laboratory tests showed BOD for 5, 10 and 15 days as 101.9mg/l. 273.3mg/l and 426mg/l respectively. Pond efficiency was 76.19%. The design experience and post design results provided knowledge about the efficiency of a waste stabilization pond and the basis of recommendation and practice in developed cities.
Effect of Flare Stack Radiation on the Mixing Height over Olorunsogo Area of Ogun State, Nigeria
Authors: Umosekhaimhe G.O. , Igbafe A.I.
Published: October 2011

Mixed layer depth, Solar and flare stack radiations, Atmospheric boundary layer Abstract: Mixing of chemical species released from pollution sources occurs at certain heights in the atmospheric boundary layer of the troposphere. Within this height, mixing of materials occurs due to convective heat transport and mechanical (wind) actions. The mixed layer height can be estimated by analyzing measured meteorological parameters. In this study, the parameterization of meteorological variables based on established mathematical models were used to compute mixed layer height over Olorunsogo in Ogun State, Nigeria. The vertical extent through which pollutants mix occurs was described in a height-temperature profile for both the day time and nocturnal characteristics. The mixing depths were computed for two locations comprising one area with gas flaring operation present and another with no flare stack present. The findings of this study revealed that mixed layer depth for the location without flaring activities, day time ranged between 1200m and 1400m, and at night time as well as early morning ranged between 150m and 400m. In contrast with the location where gas flaring occurred, mixing height ranged between 9280m and 9310m for day time and between 9100m and 9180m for nocturnal period. In addition, it was observed that pollution trapped below the flare during the day, experience rapid vertical motion due to outgoing long wave radiation (OLR) from the surface. While above the flare a vertical motion coupled with dispersion occurs under lapse rate for pollutants, but remained trapped at the inversion layer. At night time, pollutants around the flare advect vertically and experience rapid vertical dispersed motion and after going through the flare are trapped at the inversion layer. Hence most submicron sized particulate matter hardly reaches ground level over areas where gas flaring operations occur except entrainments in wet depositions predominantly through rainfall.
Free Vibration of Elastic Timoshenko Beam on Fractional Derivative Winkler Viscoelastic Foundation
Authors: Yan Qi Fang , Su Zi Ping
Published: October 2011

The fractional derivative Winkler viscoelastic foundation model is established by introducing the concept of fractional derivative. The control equations of free vibration of elastic Timoshenko beam on fractional derivative Winkler viscoelastic foundation are also built by considering the shear deformation and rotary inertia, and the control equations of elastic Timoshenko beam are decoupled by using the deformation function and considering the properties of fractional derivative, and the expressions of deflection and section corner of elastic Timoshenko beam on fractional derivative Winkler viscoelastic foundation are obtained. The influences of fractional derivative order and shear shape factor on the free vibration of elastic Timoshenko beam are discussed by numerical example.
Landslide Hazard Zoning for Highway in China Base on Remote Sensing and GIS
Authors: Wang Fu Chun , Dou Ming Jian , Wei Wei
Published: October 2011

Eight factors such as slope, incision density, incision depth, average annual rainfall, average annual >50mm rainfall days, soil types, river density, and vegetation cover ratio were used to quantify the Landslide Predict Index for highway in China. Using digital elevation data, rainfall data, thematic map of soil and river, remote sensing data of Spot/vegetation NVDI, these factors were calculated base on spatial analysis, hydrologic analysis, geostatistical analysis supported by ArcInfo9 software. The factors weights were confirmed by applying of expert estimation. The calculation results indicate that a highly spatial heterogeneity exists in the landslide Predict index for highway in China. Considering the maximum and minimum value of the index, the Landslide Predict Index for highway is divided into five levels. The landslide hazard zoning for highway is carried out base on the Landslide Predict Index mainly, then the landslide hazard zoning map for highway in China is formed.
3D Numerical Simulation for Reinforcement of Jijiata Tunnel, Liulin County, Shanxi Province
Authors: Zhang Chang Liang , Huang Shang Jin , Guo Jian Tao , Li Tong Lu
Published: October 2011

In this paper, the deformations and the stresses of surrounding rock of Jijiata tunnel, Liulin County, Shanxi Province, are all computed before reinforcement and after reinforcement, through the 3D numerical simulation. According to the computing result, before reinforcement, the computing result of the lateral displacements of the surrounding rock is consistent with the field measurement result. The maximum principle stress and the minimum principle stress are all less than the strength of the surrounding rock supporting, and this will not cause material damage so as to structural damage. But, since the tension stress is higher than the strength of the junction of tunnel arch and tunnel upright wall, this leads the larger deformation and the failure of the junction. After reinforcement, through the steel arch and the lock pin bolt’s enhanced role, the lateral displacement of the tunnel can be constrained effectively, the maximum principle stress and the minimum principle stress can be less than the strength of the surrounding rock supporting, and the tension stress can also be less than the strength of the junction. All the structures are all stable after reinforcement. Thus, this method should be selected as the proper method to reinforce the tunnel.
Model and Analysis of Dynamic Characteristic on Cable-Stayed Bridge with FEM
Authors: Liu Li Fang , Niu Xiao Xia , Yu Wang , Liu Xiao Man
Published: October 2011

Using the finite element method to establish refined finite element model and the simplified mode of cross line cable-stayed bridge "yan Hong qiao" of the yanshan university. And using ANSYS structure analysis procedures to analysis the vibration characteristic, the first10 order natural frequency and the correspo- nding vibration mode were given. Then, compared and analysis the refined model and the simplified model, the establishment of finite element model in general engineering analysis, correction method and validation suggestions.
Research on Rust Bilge Cracking of Reinforced Concrete Pier in Marine Environment
Authors: Luo Xiao Feng , Xing Guo Hui
Published: October 2011

Based on coupled thermal-mechanical method, rust bilge cracking of reinforced concrete pier in marine environment has been studied in this paper. Because of the similarity of differential equations of chloride diffusion and transient heat transfer, chloride diffusion is completed by using the transient heat transfer method. The chloride ion concentration at the reinforcement surface is obtained and is taken as temperature load at each time step. After introducing the equivalent time-varying coefficient of thermal expansion, the corrosion-induced reinforcement expansion and concrete cracking are simulated by the thermal expansion method. Numerical results show that the method is reasonable and feasible.
Research on Supporting Techniques of Deep and Large-Section Coal Roadway Blow Thin Fractured Bedrocks
Authors: Ma Kui Sheng , Song Min , Fu Hou Li
Published: October 2011

This paper is basis on previous studies, taking The main haulage roadway of the western district of Zhaogu No.1 mine ,which belongs to Jiaomei group, as the background of study. On the basis of understanding the mechanical properties and engineering characteristics of soft rock, proposing the stability control mechanism and supporting scheme design countermeasure of fractured soft rock roadway. Numerical analysis was made to the stability of roadway surroundings used the FLAC-3D finite element analysis software, and a set of reasonable supporting technology schemes and parameters were proposed.
State of the Art on Seismic Design and Research of LNG Tanks
Authors: Zhao Ming , Liu Lei , Li Su Zhen
Published: October 2011

As a part of lifeline system, the LNG tanks seismic design is very important because of the increasing danger caused by the rapid economic development. However, the LNG tanks design codes are absent in China. The application of the double-layer spherical tank should be promoted, because of its advantages including better mechanical behavior, less maintenance cost etc. The state of the art about the design aspect is reviewed, especially the low temperature material properties, the liquid-structure interaction analysis techniques, the isolation and damping of tanks. The potential aspects for the future design are also discussed.
Influence of Tie Beams of Pier on the Seismic Performance of a Continuous Rigid Frame Bridge with Twin-Legged Piers
Authors: Nie Yun Jing , Yan Xu , Li Tie Ying
Published: October 2011

In this paper, the influence of tie beams for piers is investigated on the dynamic characteristics and the seismic performance of a continuous rigid frame bridge with twin-legged piers. Modal analyses and the linear seismic response analyses are performed on a practical continuous rigid frame bridge with twin-legged piers with no tie beam, one tie beam and three tie beams of pier, using software Midas/civil. The findings indicate that installing tie beams of pier can increase the natural frequencies of this kind of bridge. Setting tie beams of pier is disadvantageous to the seismic performance of the bridge beam, but advantageous to improving the seismic performance of the twin-legged piers. The influence of tie beams of pier on the seismic performance on the whole structure is relevant to the pier height. These analytical results provide a reference for the seismic design and analysis of similar structures.
Research on Structural Composition and Seismic of Gypsum - Adobe Wall Dwellings
Authors: Zhou Tie Gang , Ma Chen , Xu Ying
Published: October 2011

Gypsum-adobe wall structure is a new type of green earth building. The feature of its structure is that the wall uses adobe and plaster as its main materials.The wall is erected by putting rods or stems of plants between layers of adobe, and is poured gypsum slurry into the gaps between adobe bricks and on the wall surface. Then adobe and plaster solidify and come to a composite wall structure. Finally，Gypsum and adobe bricks interact and bear stress together. This paper focuses on fully describing the shaking table test of a 1/4 scale house model of the structure. The Test results and engineering practice show that the single-storey gypsum-adobe wall structure has a good seismic performance and is worth promoting in residential construction of the drought areas.
Pullout Test Study on Flexible Joint of Ductile Iron Buried Pipelines
Authors: Gu Fan , Zhou Jing Hai , Hai Hong , Song Yan Sheng
Published: October 2011

Axial pullout test on ductile iron buried pipelines with MTS testing machine was carried out, the relation curve between axial tension and flexiable joint displacement was gotten, the functional failure mechanism of flexible joint of buried pipeline was discussed. The results indicate that there is relative displacement between pipe and soil under seismic action, meanwhile, the acting force between pipe and soil is the viscous damping force which is related to pipe-soil relative speed.
The Dynamic Testing Method for Damage Diagnosis of Multi-Story Masonry Buildings
Authors: Li Feng Ge , Yu Hong
Published: October 2011

A new method to diagnose the damage of masonry structure using artificial network is brought forward. The frequencies and the ratio of change for any two orders various frequencies is chosen as a damage indicator and is used to train the BP neural network, which can diagnose the damage of masonry structure. The result of the numerical computation shows that the BP neural network can diagnose the damage of masonry structure.
Analysis and Assessment of Lishan Potential Landslide of China
Authors: Hong Yong
Published: October 2011

This paper presents the monitoring records of the deformation on the North Slope of Lishan Mountain in Lintong County, Shanxi, China. On the basis of the monitoring results on the site and the creep tests on the soil samples, the mechanism of the potential dangerous landslide was analyzed. The existence of lock segment in the slope and its time effect are regarded as the important controlling factors in the development process of Lishan potential landslide which has the possibility of becoming a rapid disastrous landslide.
Research on Sustainable Development of Sports Builings
Authors: Li Hui Min , Jia Lin Xin , Yan Wen
Published: October 2011

The development of sports and the hold of the sports events have promoted the construction of sports venues. However, the government's financial burden restricts the development of sports venues. How to seek a new financing pattern that not only can alleviate the government's pressure of the preparation, but also can build a batch of sports venues to meet people's increasing need, it is the emergency problems to be solved. The three patterns-BOT pattern, PPP pattern, PFI pattern are analyzed, they are suitable for different sports venues. The research not only can promote foreign investment and private capital into the sports facilities, but also can reduce government's financial burden.
Spatial Effect Analysis on Shaking Table Tests of Subway Station Structure in Soft Ground
Authors: Zuo Xi , Chen Guo Xing , Wang Zhi Hua , Du Xiu Li
Published: October 2011

Based on the test data of shaking table tests of subway station structure in soft ground under both near-field and far-field earthquakes, the spatial effects of peak ground acceleration (PGA) of soft ground as well as peak strain response of the subway station structure are analyzed. The results show that the peak acceleration of measuring points on both major and minor planes increases with the growing peak acceleration of earthquake. The law of PGA and frequency spectral character of measuring points on different observation planes or at different depth varies with each other, and there presents remarkable spatial effect. The peak strain of central cylinders on the major plane appears larger than that on the minor planes. There are sharp contrasts among the peak strain responses in different spatial positions of the station structure.
Experimental Study on Dynamic Performance of Steel Frame with Reinforced Connection
Authors: Wang Yan , Chen Li Quan , Zhang Li Ya , Tao Shuai
Published: October 2011

Half scaled specimen of steel frame with widen flange connection was manufactured and carried out a pseudo-dynamic experiment. Dynamic characteristics such as the base shear of the steel frame, acceleration response, displacement response of each floor and hysteresis curve were obtained through the TUT control system and data acquisition system. The results show that the acceleration response and displacement response for each floor of the steel frame with widen flange connection tally with actual projects and can well reflect the overall seismic performance of the structure. The steel frame is always in the elastic stage under the earthquake, it has stable hysteretic behavior and good energy dissipation capacity. Reinforced connection improved the seismic performance of the steel frame effectively, and the experimental results can provide reference for the engineering applications.
The Study on Mechanical Impedance and Piezoelectric Impedance for Cantilever Beam Based on FEA Method
Authors: Zhang Jun , Gao Qin , Wu Jian Zhong , Tao Juan
Published: October 2011

The mechanical impedance and the piezoelectric coupling impedance response spectrum, the resonant vibration mode and he resonance frequency of the cantilever beam was analyzed by means of FEA for getting the relationship between mechanical impedance and piezoelectric impedance. The results showed that: Through the comparison between the two, both resonance frequency and resonance modes are the same basically, which also showed that the change of piezoelectric impedance changes with the mechanical impedance change. Piezoelectric impedance is the electric reflection of mechanical impedance. It provides a sound theoretical basis and research methods for the piezoelectric impedance damage identification and health monitoring technology.
The Optimization and Application of Riprap Concrete Technology
Authors: Yin Zhi Guo , Li Hui Min
Published: October 2011

Riprap concrete technology is the effective measures to control the temperature cracks in construction of mass concrete. But in the implementation process, there are some problems. In this paper, riprap concrete technology problems of the actual implementation are proposed, and the optimal solution is given. At last, relation to Dinghan gardens project raft foundation of mass concrete works, the material mix proportion is described in the paper. At the same time, construction technologies are outlined including pouring by segmentation and layer, riprap technology, bleeding treatment and concrete maintenance. The construction strength is tested by comparison test of normal maintenance. The results present that it not only solve construction problems of mass concrete in summer, but also shorten construction period and decrease construction cost.
New High Floating Concrete Mortar Material Develop
Authors: Bao Li Xin , Wang Fei Yu
Published: October 2011

Concrete mortar powder body composition and the body of thick liquid to compound method, have analysed difference, match the property that takes off mortar than condition , have reached the best mortar that is more practical than project practice to compound method. The mortar that made can be applied extensively in project field.
Loading Analysis of Edge Members in SPSW with Opening
Authors: Lan Tao , Hao Ji Ping , Xu Hai Jun
Published: October 2011

Taking a group of SPSW with openings with or without edge members as example, this paper states the importance of edge members in view of initial stiffness, ultimate bearing capacity and ductility. First, FEM analysis is carried out to study the reasonable stiffness-range and it is found out when the inertia moments ratio varies from 6 to 8, edge members not only provide adequate anchorage, but also resist loads directly with main frame. Then, an unified calculation model called USMO is proposed, whose key point is to add inversed compression bars with stiffness to tension zone to simulate the increase of ultimate bearing capacity, leaving shearing part same to USM.
Cellular Automata-Based Chloride Ion Diffusion Modelling of Concrete Bridge under Multifactor Coupling Action
Authors: Zhu Jin Song , He Li Kun
Published: October 2011

In order to accurately simulate the diffusion of chloride ion in the existing concrete bridge and acquire the precise concentration of chloride ion at any time, a Cellular Automata(CA)-based model is proposed. Firstly, the process of chloride ion diffusion is analyzed by the CA method and a nonlinear solution to the Fick’s second law is obtained. Secondly, considering the impact of various factors such as stress states, temporal and spatial variability of diffusion parameters and water-cement ratio on the process of chloride ion diffusion, the model of chloride ion diffusion under multifactor coupling is presented. Finally, a chloride ion penetrating experiment is used to prove the effectiveness and reasonability of this present method. A T-type beam is taken as an illustrative example to analyze the process of chloride ion diffusion.
Analysis of Extreme Temperatures in Bridge Deck Pavements
Authors: Li Hai Bin , Wang Qian
Published: October 2011

Thermal stresses at the extreme temperature conditions can cause various pavement distresses. These distresses may degrade the structural performance of bridge deck pavements (BDP), such as, upheaval, low-temperature cracking, reflective cracking, etc. It is essential to understand the influence of the extreme temperatures on the pavement distresses. Based on the analytical solutions of temperature in BDP, the simplified formulae for calculation of stresses for the extreme temperatures (maximum and minimum temperatures) in BDPs were developed in this study.The calculated results obtained from the developed simplified formulae were then compared with the data measured in the field. The differences between them were found to be within 2°C.