bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimum Design and Fairness of the Surfaces for Mold with Three Revolving Positions
Authors: Gu Li Zhi , Fan Qi Yong , Gao Y.
Published: March 2009

Intensive processing for meat requires security, reliability, and efficiency, dreadfully
demanding the automation of the process. A newly mold system was optimum-designed with three
revolving positions for automated sticking in the material feeding, compression, and productknockout.
The ratio of compression was taken with values in the range of 15-25% for the perfect
shape and stringing rate. Surfaces of the mold were designed with mathematical planning of SUMT
penalty function, and referent parameter values were obtained. Final decision was chosen from the
nine designs, reaching the requirements that the contours of the mold on the section was so
designed that it gained a closed figure approaching a circle, with the ratio of long and short axels
being about unit. The curves were simple and few, and faired. Virtual and physical experiments
have shown that the mold design is of feasibility, and with the current study the difficult problems
have been solved of productivity, stringing rate, and automation of the meat strings, setting up the
technical basis for the transformation of the production patterns from the conventional
labor-concentration to the modern technique-concentration in intensive meat processing industry.
Study on a Knowledge-Reuse-Based Rapid Product Design Process
Authors: Guo Hun , Tang Guo Xing , Zuo Dun Wen , Liu T.J. , Jin W.D.
Published: March 2009

Design reuse is the application of past designs knowledge and successful experience to current design process and it is a significant method for rapid design. A knowledge-reuse-based rapid product design model is proposed and a three-factor product design iterative process model is studied. Finally, it is applied successfully in the rapid product design of construction machinery combining with the requirement of the construct machinery product design.
Stochastic Fractal Modeling and Process Planning for Machining Using Two-Dimensional Iterated Function System
Authors: Li Yu Hao , Feng Jing Chun , Li Y. , Wang Yu Han
Published: March 2009

Self-affine and stochastic affine transforms of R2 Iterated Function System (IFS) are
investigated in this paper for manufacturing non-continuous objects in nature that exhibit fractal
nature. A method for modeling and fabricating fractal bio-shapes using machining is presented.
Tool path planning algorithm for numerical control machining is presented for the geometries
generated by our fractal generation function. The tool path planning algorithm is implemented on a
CNC machine, through executing limited number of iteration. This paper describes part of our ongoing
research that attempts to break through the limitation of current CAD/CAM and CNC
systems that are oriented to Euclidean geometry objects.
Simulation of Cutting Force in Turning Machining Process on CK7815 NC Lathe
Authors: Dong Yu Hong , Xu H.T. , Lin H.
Published: March 2009

In order to improve NC machining precision this article analyzes the effects of cutting
force on NC machining precision by means of simulation, and builds up the mathematical models of
CK7815 feed drive system and radial action force of cutting feed, in order to study the effects of
cutting load torque and radial cutting force on work pieces processing precision. The simulation
results illustrate that cutting load torque and radial cutting force have respectively effects on axial
precision and radial precision of work piece. The bigger is cutting load torque, the bigger is axial
error. The smaller is cutting process coefficient and the higher is converting spring stiffness of lathe
and tool, the smaller is radial error. In practice NC machining precision is improved by trying to
decrease the cutting load torque and cutting process coefficient and increase converting spring
stiffness.
A Reliability Analysis Method Based on Execution Scenario for Modular NC Software
Authors: Yao Xin Hua , Fu Jian Zhong , Chen Zi Chen
Published: March 2009

To describe the modular structure of numerical control (NC) system and deal with the problem of interference between modules in software reliability analysis, a module dependency graph (MDG) was presented and a scenario-based scheme was proposed. MDG describes reliability of module in different application environment, module dependency and structure of software with establishing maps among modules, execution scenarios and reliability. According to the information shown in MDG, an algorithm based on the idea of traversing directed graph in graph theory was proposed. The algorithm calculates the reliability of scenario with breadth-first principle. The reliability of system could be obtained from reliability and running frequency of scenario. The scheme eliminates the defects of the conventional methods which ignore module correlation. Case study proves the scheme could evaluate the reliability of NC software effectively.
Surface Integrity Research on Barrel Finishing of Crankshafts’ Part
Authors: Li Wen Hui , Chen H.L. , Yang Sheng Qiang
Published: March 2009

At present, crankshafts are finished mostly by abrasive cloth and manual steel brush,
which is not ideal on finishing quality, efficiency and cost, especially cleanness degree does not
meet design and use request. So a new horizontal spindle barrel finishing for crankshafts has been
developed. To contrast the finishing effect, surface geometric characteristic, physical-mechanical
property, cleanness degree etc. are analyzed, which indicates this process can comprehensively
improve the surface integrity of crankshafts’ part. Simultaneously, this process can decrease cost,
reduce labour intensity, improve efficiency, and easy to automation. Its application has wide
economic and social benefits.
The Reconfigurable Embedded NC System Based on FPGA
Authors: Wu L.M. , Hu Wan Bin , Lai Nan Hui , Wang G.T.
Published: March 2009

The hardware and software design method of reconfigurable embedded NC system which
makes use of FPGA’s abundant logic resources and programmable characteristics is presented. It
introduces the scheme of a embedded NC system which has regarded FPGA as the control center. It
mainly represents the thought of reconfigurable design, the speed control of stepping motor, and the
communication of FPGA and PC. As a result, this system has fast response and strong
reconfiguration ability. It can reduce the number of peripheral interface devices and result in costreduction.
Scheduling of Multiple Projects with Resource Constraints Using Genetic Algorithms
Authors: Qiao Li Hong , Wang C.
Published: March 2009

A scheduling approach using genetic algorithms (GA) was presented to optimize multiple projects for quality project period performance with resource constraints. The model of the approach and key parameters of the algorithm including chromosome encoding and decoding, fitness computation, initial population, selection and crossover were conducted. A precedence feasible list was used in the chromosome encoding and decoding operation to reduce search space. An efficient crossover method was developed to avoid the procedure of chromosome recovery. A comparison was made between the algorithm and a heuristic scheduling method with an example. The result validates the superiority of the approach.
Self-Propagating High-Temperature Synthesis (SHS) of Advanced High-Temperature Ceramics
Authors: Mishra Suman K. , Pathak Lokesh C.
Published: March 2009

Over the years, the self-propagating high-temperature synthesis (SHS) has become an interesting research field to prepare a large numbers of advanced materials. Recently, the demands for high temperature advanced ceramics have further intensified the research on SHS for efficient material preparation. Several reviews, large numbers of papers and patents on various aspects of material production by SHS are available in literature. These are scattered and it is desirable to have a comprehensive review of the literatures that not only helps the researchers but also guide the beginners in this area. In this paper, we have emphasized our contributions on synthesis of various advanced high temperature ceramics, the borides, carbides, oxides and their composites by SHS processes. Several advantages and disadvantages of the SHS technique for advanced high temperature (HT) materials are highlighted. The preparation of nano-sized powders and finegrained in-situ high temperature ceramic composites through SHS is specially mentioned.
Nanoscale Alumina-Reinforced Aluminum Matrix Composites: Microstructure and Mechanical Properties
Authors: Han Ji Xiong , Chen Yong Ching , Vasudevan Vijay K.
Published: March 2009

Studies were carried out on microstructure evolution and mechanical behavior of an Al matrix–nanoscale Al2O3 particulate-reinforced composite. The thermal stability of the composite, evaluated by heat treating specimens at temperatures from 300 to 600 °C for times varying from 1 to 100 hours, revealed that the nano-sized (30-100 nm) Al2O3 particles present in the as-received/ascast material coalesced into larger particles, but with sizes still in the 100 to 500 nm range. Despite the coarsening of the particles, high hardness was retained. The tensile properties of both the as-cast DSC material and those thermally soaked for 500 hours at a number of temperatures were evaluated. The results showed that the yield strength was quite high (283 MPa) at room temperature and decreased nearly linearly with temperature, though values as high as 110 MPa were obtained at 400oC. Thermal soaking did not have a detrimental effect on strength. Although the macroscopic ductility of both unsoaked and soaked materials remained quite low over the entire temperature range, SEM observations of the fracture surfaces provided substantial evidence for high localized plasticity as manifested by stretching, tearing and void formation in the Al matrix around the oxide particles. Possible strengthening mechanisms, including grain size reduction, Orowan bypass and forest hardening, were considered and modeled. Good agreement between the calculated and experimental strengths was obtained, and majority of the strengthening at room temperature was found to come from forest hardening (i.e, increase in dislocation density caused by the thermal expansion mismatch between Al and Al2O3), with secondary contributions from the Orowan mechanism. TEM observations provided confirmatory evidence for these mechanisms. The decrease in strength at higher temperatures was attributed to a diminishing contribution from forest hardening due to recovery processes.
Effect of Saline Solution on the Development of Compressive Strength in Apatite Based Bone Cement Containing Demineralized Bone Matrix
Authors: Kim Young Woo , Chung Tai Joo , Jang Ju Woong , Oh Kyung Sik
Published: March 2009

Compressive strength of apatite type bone cement was analyzed with respect to the concentration of setting agent and types of saline solution used for storage after setting. With the increase of the concentration to 2 M, the density of paste decreased. However, the compressive strength of cement was not necessarily correlated with the density and dependent on the type of saline solution used for storage after setting. One solution led rather porous paste and the strongest specimen from the series was obtained under the maximized amount of apatite within the paste. The other saline solution induced the more dense paste after setting. In this series, the strongest specimen was obtained under the coexistence of low crystalline apatite and dicalcium phosphate dihydrate. The difference between two saline solutions was explained in terms of the solidity of skeleton formed by apatite.
Influence of Mixing Liquid on the Properties of Calcium Aluminate Cement
Authors: Morejón-Alonso L. , Santos Luis Alberto , García Carrodeguas R.
Published: March 2009

The effect of using Na2HPO4 solution as mixing liquid in the physicochemical and mechanical properties of calcium aluminate cement (CAC), with a view to a possible reinforcement additive of conventional α-TCP-based CPC was studied. The results showed that the degree of the hydration reaction of CaAl2O4 (CA) increased when Na2HPO4 solution was used as mixing liquid. The porosity of cement was also lower (37.9 ± 1.3 %) than for H2O (33.2 ± 3.6 %). The values of compressive strength for cements prepared with both mixing liquids were lower than 3 MPa due to the excessive L/P ratio employed and large porosity. After immersion in SBF, only the Al(OH)3 hydrate is observed and no other crystalline hydrated calcium aluminate nor calcium phosphate was formed in any of the cements. Both cements released Ca ions to, and removed P ions from SBF, being this effect more remarkable when Na2HPO4 was used. As for other CAC, no Al was released to the SBF and no potential toxicity due to this ion should be expected.
Osteoconductivity of Hydrothermally Synthesized Beta-Tricalcium Phosphate Composed of Rod-Shaped Particles under Mechanical Unloading
Authors: Gonda Yoshinori , Ioku Koji , Okuda Takatoshi , Shibata Yasuaki , Kamitakahara Masanobu , Kawachi Giichiro , Yonezawa Ikuho , Kurosawa Hisashi , Ikeda Tohru
Published: March 2009

Spherical beta-tricalcium phosphate (b-TCP) granules synthesized using a unique dropping slurry method expressed good osteoconductivity with prominent bone apposition and bioresorbability when implanted into the rat femur (Gonda et al., Key Eng. Mater. 361-363:1013-1016, 2008). The spherical b-TCP granules were implanted into the bone defect created in the distal end of the right femur of each 8-week-old female Wistar rat. To analyze performance of the spherical b-TCP granules as bone substitute in the bone with reduction in osteogenic potential, the right sciatic neurectomy was performed after implantation and the right hind limb was kept unloaded for 2 weeks before euthanization. Four weeks after implantation, some spherical b-TCP granules with resorption in part were surrounded by newly formed bone. Eight and 12 weeks after implantation, most of the residual b-TCP granules were embedded in newly formed bone, and total volume of the implant and newly formed bone was more than the other portions of the bone or the bone of control animals. Osteoclast activity in the implanted area was also higher than the other portions of the bone or the bone of control animals. Replacement of the intraosseous residual b-TCP granules for bone progressed at 12 weeks after implantation compared to those at 8 weeks after implantation. These data suggested that the spherical b-TCP granules stimulated osteogenesis and osteoclast activity of the unloaded bone.
Cytotoxicity and Adhesion Evaluation of Nanothickness Ca/P-Based Bioceramics Coated Titanium
Authors: Ramirez Caroline M. , Coelho Paulo Guilherme , Granjeiro José Mauro
Published: March 2009

Incorporation of bioceramics on the surface of dental implants has been utilized in an attempt to increase biological response of bone to materials. This paper reports the in vitro biological evaluation of Ca/P-based nanothickness bioceramic coated alumina-blasted/acid-etched titanium implants (AB/AE nanotite implant) and compare its performance to the untreated and uncoated implants, Ca/P-based nanothickness bioceramic coated untreated implants (untreated nanotite implant), alumina-blasted/acid-etched titanium implants (AB/AE implant) and hydroxyapatite plasma-sprayed implants (PSHA Implant). Balb/c 3T3 fibroblasts were used to asses the cytocompatibility of implant materials according to ISO-10993-5 protocols. Osteoblasts from Balb/c femurs seeded onto different implant surfaces showed the effect of surface topography and chemistry on cell adhesion. The results showed that all implants were not cytotoxic and that PSHA and AB/AE nanotite implants favored osteoblasts adhesion.
Improvement of Apatite-Forming Ability of Titanium Metal Enriched with Calcium Ion on its Surface
Authors: Kizuki Takashi , Takadama Hiroaki , Matsushita Tomiharu , Nakamura Takashi , Kokubo Tadashi
Published: March 2009

It has been shown that titanium metal subjected to NaOH and heat treatments spontaneously forms a bonelike apatite on its surface in the living body and bonds to living bone. However, its apatite-forming ability was liable to decrease when the treated titanium metal was stored in humid environment. In the present study, the NaOH-treated titanium metal was soaked in a CaCl2 solution at 40°C for 24h, heat-treated at 600°C for 1h, and then soaked in ultrapure water at 80°C for 24h. Calcium titanate was formed on the surface of the titanium metal 1µm in thickness by these treatments. The resultant titanium metal showed high scratch resistance and high apatite-forming ability in a simulated body fluid. This high apatite-forming ability was maintained even after the titanium metal was kept in 95% relative humidity at 80°C for 1 week.
Gentamicin Sulphate Release from Bioactive Ceramic Calcium Silicates
Authors: Cortés-Hernández Dora A. , Bretado-Aragón Luis A. , Ortega-Lara W. , Rentería-Zamarrón David , Salinas-Delgado Y.
Published: March 2009

Gentamicin sulphate was mixed with two different sol-gel derived calcium silicates (akermanite or wollastonite). Each of the mixtures was isostatically pressed. Samples were immersed in simulated body fluid for 21 days. The presence of the antibiotic showed no effect on the in vitro bioactivity of the ceramics. For evaluating the gentamicin sulphate release, samples were immersed in a phosphate buffered saline solution for different periods of time. Most of the gentamicin sulphate was released during the first 7 days. However, akermanite showed a lower antibiotic release rate than that observed for wollastonite.
Bioactive Ceramics Based on Nb2O5 and Ta2O5
Authors: Marques C. , Louro Luis Henrique Leme , Prado da Silva Marcelo Henrique
Published: March 2009

Bioactive ceramics have the ability to chemically bond to bone. This class of biomaterials can be used as coatings on metallic implants, alloplastic bone defect fillers and as scaffold for tissue engineering. The most widely used bioactive ceramics are hydroxyapatite, Ca10(PO4)6(OH)2 and tricalcium phosphate, Ca3(PO4)2. This study presents new bioactive ceramics based on Nb2O5 and Ta2O5. These materials were produced from bioinert ceramics chemically activated by an alkali hydrothermal treatment. Scanning electron microscopy, energy dispersion X-ray spectroscopy and X-ray diffraction analyses on samples incubated in simulated body fluid showed the presence of bone-like apatite, confirming that the modified ceramics surface became bioactive.
A Bioactive Glass/Dental Porcelain System by the Sol Gel Route: Fabrication and Characterization
Authors: Goudouri Ourania Menti , Kontonasaki Eleana , Kantiranis Nikolaos , Chatzistavrou Xanthippi , Papadopoulou Lambrini , Koidis Petros , Paraskevopoulos Konstantinos M.
Published: March 2009

Melt derived bioactive glass- porcelain system is reported to be bioactive but with a slow
rate of bioactivity. The aim of this work is to fabricate and characterize bioactive glass/dental
porcelain composites produced by the sol-gel method. Fourier Transform Infrared Spectroscopy
(FTIR), Scanning Electron Microscopy (SEM) and X-ray Diffractometry (XRD) were used to
characterize the fabricated materials. The FTIR spectra and the XRD patterns confirm the presence
of both constituents in the mixtures, while the dominant crystal phases in bioactive glass/dental
porcelain specimens are leucite and wollastonite.
Energy-Controlled Design of Reinforced Ultra-High Performance Fiber Concrete Slabs against Airblast Loads
Authors: Wu Chengqing , Oehlers D.J. , Rebentrost M. , Leach J.
Published: March 2009

Displacement-controlled design method is now being used by current guidelines such as TM5 and ASCE to design RC members against airblast load. If the maximum deflection of the designed member under airblast loads is less than the allowable deflection, the designed member is considered to be safe. Although the displacement-controlled design method is easy to use, it may not result in a design having maximum energy-absorption capacity against airblast loads, especially for a design of a reinforced ultra-high performance fibre concrete (RUHPFC) member which is of both high strength and high ductility, that is, high energy-absorption capacity. In this paper, a layered analysis model allowing for varying strain rates with time as well as along the depth of the member was used to calculate energy-absorption of a simple supported RUHPFC slab under airblast loads. An optimal reinforcement ratio of the slab was achieved by maximizing the energy absorption of the slab under different reinforcement ratios. The energy-controlled design method was validated by field blast tests. Using the validated design method, a designed slab with the optimal reinforcement ratio was also tested and the effectiveness of the design was demonstrated.
Fracture Behaviors of Dam and Wet-Sreening Concrete by Direct Tensile Test
Authors: Zhao Zhi Fang , Pang Bo , Zhao Zhi Gang
Published: March 2009

The emphasis of this paper is to experimentally study the fracture behaviors of dam and wet-screening concrete such as softening curve, uniaxial tensile strength , maximum crack width and fracture energy .
The direct tension tests were performed on prismatic specimens with no initial notch include dam concrete specimens which size is 250mm×250mm×500mm and wet-screening concrete specimens which size is 150mm×150mm×300mm by employing a servo-hydraulic closed-loop testing machine with large stiffness. The uniaxial tensile load-strain curves, uniaxial tensile stress-strain curves, uniaxial tensile stress-deformation curves were acquired. On the basis of principle of fracture mechanics of concrete, the stress-crack width curves and the relative stress-relative crack width curves were obtained. Finally, the expressions of softening curves and fracture parameters such as , and of dam and wet-screening concrete were achieved. The relationships of the foregoing fracture parameters between dam concrete and wet-screening concrete were discussed in this paper.
The achieved softening curves and fracture parameters can provide input data for the fracture simulating analysis of dam and wet-screening concrete.
Shear Capacity of Reinforced Concrete Beams under Biaxial Bending Based on Equivalent Cross-Section Method
Authors: Zeng Qing Xiang , Cai Jian
Published: March 2009

Based on the analysis of reinforced concrete beams under biaxial bending, an equivalent cross-section method is proposed to calculate the shear capacity of the beams. According to the two basic equivalence principles, a biaxial flexural beam is changed into a uniaxial flexural member, and the shear strength of biaxial flexural beam is calculated as a uniaxial flexural member. Furthermore, the interrelationships among the equivalent cross-section and the neutral axis inclination as well as the ratio of depth to width of the cross-section are deduced in advance. The ratios of some typical cross-section’s equivalent dimensions to its original ones are pointed also. In order to verify the availability of the equivalent cross-section method, some academic references about the ultimate strength of biaxial flexural beams are consulted in this paper, and the shear capacity computing methods by literatures for uniaxial flexural beams are adopted in the strength calculation of biaxial flexural reinforced concrete simply supported beams with stirrups or without stirrups. The comparison between the calculation results and experimental results shows that the presented equivalent cross-section method is feasible and practical which can be used as a reference in practice design.
Finite Element Modeling of Prestressed Hollow Core Slab Strengthened with CFRP Sheets in Flexure and Shear
Authors: Kalimur Rahman M. , Mahmoud Isam A. , Baluch M.H.
Published: March 2009

Precast concrete construction with prestressed precast hollow core slab as floor and roofing is being extensively used in the Gulf region. These one way slabs are sometimes subjected to unforeseen loads with a partition wall in shear zone or as a cantilever. A detailed experimental program involving full-scale load testing of hollow core slabs has been conducted involving testing of virgin and CFRP strengthened slabs in flexure and shear. This paper presents the results of the experimental and numerical evaluation of flexural and shear behavior of the hollow core slabs. The hollow-core slabs were modeled using the nonlinear finite element software DIANA and the load deflection behavior and ultimate capacity were evaluated numerically. For the FE model, concrete was modeled using Drucker-Prager with tension cut-off failure criterion, and Von-Mises plasticity with multilinear isotropic hardening was used to model the prestressing strands. Comparison between the experimental and the numerical results indicated that the finite element model predicted experimentally determined results successfully.
Analysis, Design and Construction of Complex Concrete Structures for the Water Treatment Industry
Authors: Statton Peter , Salu Michael
Published: March 2009

The design and construction of concrete water treatment and storage structures in Australia has catered for the existing markets. The next generation of these structures needs a more sophisticated approach. Engineers who analyse and design water treatment plants, or water and liquid storage structures, as well as other complex reinforced and pre-stressed concrete structures, will find this paper of interest. Advanced water treatment plants and water factories for recycling domestic and industrial waste water have introduced new complexities into concrete tank design. Two recently constructed Australian water purifying plants provide examples of the theoretical and practical challenges of designing and constructing the large and complex process vessels required by modern plants to produce large volumes of high-quality water.
Simplified Dynamic Finite-Element Analysis for Three-Dimensional Pile-Grouped-Raft-High-Rise Buildings
Authors: Xiong Hui , Shang Shou Ping , Huang Liang
Published: March 2009

Combined with the respective advantages in S-R(Sway-Rocking) impedance concept and finite-element method, a simplified 3D structural dynamic FEM considering composite pile-group-soil effects is presented. The structural members including piles are modeled by spacial beam or shell elements, and raft-base is divided into thick-shell elements with its spring-dashpot boundary coefficient obtained by impedance backcalculated. The mass-spring elements for soil between piles are set to simulate vertical, horizontal pile-group effects by strata-equivalent approach. The soil beside composite body is separated into near-field and far-field parts. The former is modeled by nonlinear spring-dashpot elements based on Winkler’s hypothesis, while the latter is modeled by a series of linear mass-spring-dashpots. With the effects of boundary track forces and energy radiation, the presented model enables researchers to conduct the time-domain nonlinear analysis in a relatively simple manner which avoids sophisticated boundary method and solid-element mesh bringing with tremendous computational cost. The seismic effect on dynamic interaction of pile-soil-complicated structures would be efficiently annotated from two structural engineering and geotechnical engineering aspects and the numerical calculation effort would be drastically decreased too. The complete procedure is mainly performed using the parametric design language assembled in the Finite Element Code Ansys. With the dynamic analysis of foundation and superstructure for a pile-supported 15-storey building, the influence of the participant effect on structural dynamic response will be depicted by various dynamic parameters of pile-soil-raft foundation in detail. Not only do the results have an agreement with some conclusions drawn by the general interaction theory, but also certain of phenomena which would be disagree with that by general analysis is involved. Even with the finite-element meshes for 68 piles, the time-history analysis procedure for PGSS (Pile-Group-Soil-Superstructure) system and the qualitative evaluation with various SSI parameters can be also fulfilled efficiently and rapidly by presented means. These results may be of help to the designers to quickly assess the significance of interaction effect for the high-rise buildings resting on any type or layout of pile-group foundation.
Finite Element Analysis of Small Span Reinforced Concrete Trough Railway Bridge
Authors: Zou Zhong Quan , Enochsson Ola , He Guo Jing , Elfgren Lennart
Published: March 2009

The static behavior of a reinforced concrete trough railway bridge is analyzed by finite element method. The influences of load distribution fashion, supporting width of the bearings and the additional support beneath the girder are investigated; and the spatial effect of the stress distribution is studied as well. To confirm the analysis accuracy, the results are calibrated with the field load test results. It is found that the influence of load distribution fashion is minor and negligible, while those of supporting width and additional support are not negligible; and the spatial effect is significant.
Development and Application of Networked Structural Laboratories System in Current Hierarchical Network Environment
Authors: Guo Yu Rong , Xiao Yan , Hu Qing , Fan Yun Lei
Published: March 2009

A networked structural laboratories system for seismic simulation of structures is presented. It consists of an independent network based communication platform (NCP) and various applications based on NCP. The NCP was developed based on client/server concept along with a proposed data model and communication protocols. It is capable of transferring control and feedback data among computers connected by Internet that is a hierarchical network with ubiquitous deployment of middleboxes, such as firewalls and network address translators. Communication speed tests were conducted in various network environments. Applications for hybrid dynamic test of bridge and building structures have been developed and remote hybrid tests of structures were carried out among the Hunan University, the Harbin Institute of Technology, and the Tsinghua University.
Analysis of Aseismatic Performance of Reinforced Concrete Frame Side Joints Strengthened with Carbon Cloth
Authors: Liu Hai Qing , Yuan Jing , Hou Shao Ying , Xue Yang
Published: March 2009

Application of carbon fiber material to reinforced concrete structure is a systems engineering involving materials, design and application, which is also an applied science involving numerous subjects. Carbon cloth is used to reinforce structures in many projects, but the study on strengthening frame joints is still little. Especially the study on aseismatic performance of frame structure side joints is much less. In this paper, the author established constitutive relation of RC frame side joints strengthened with carbon cloth and made a numerical simulation analysis of four side joints of beam column plate under low-cycle repeated load with ANSYS, a software based on finite element analysis. The author analyzed the failure mode and the mechanism under stress, found out the characteristics of hysteretic curve of such kind of joints, acquired ductility coefficient and equivalent viscous damping ratio coefficient and studied the structure ductility and seismic-energy-dissipating capacity. It was shown that failure mode transited from shear brittle failure of core space to ductile failure of plastic hinge of beam end, joints’ seismic-energy-dissipating capacity and ductility were improved observably, joints’ displacement between layers was reduced, and rigidity and aseismatic capacity of component were improved after the joints’ being reinforced with carbon cloth. And aseismatic performance of structure was superior obviously.
Research of Fireproof Performance of Steel Frame after Subjecting to Impact Loads
Authors: Zheng Li Xin , Zha Xiao Xiong , Ma Chen Jie
Published: March 2009

In recent years, many structures subjected to impact load and fire collapse, such as the event of “9.11”, which is the largest tragedy in the 21 century. Structures subjected to impact load can be damaged in varying degree. This damage can reduce the bearing capacity withstanding fire badly. So how to study the response is very urgent. This paper mainly studies the bearing capacity withstanding fire after subjecting impact load using the finite element software ABAQUS. we use the simplified model studying the bearing capacity withstand fire of the structure elements after subjecting impact load, finally we use the software MATLAB get a coefficient, This coefficient can give a reference when we design some important structures withstanding fire.
Experimental Study on Shear Failure of High-Strength Concrete Beams with High-Strength Stirrups
Authors: Yi Wei Jian , Lv Yan Mei
Published: March 2009

19 RC beams with shear span-to-depth equal to 3 were tested under a stiff testing facility, and complete load-deflection curves including the post-peak branch were obtained. Based on the test results the effects of concrete strength, stirrups strength, inclined stirrup angle, the amount of longitudinal reinforcement on failure mode, shear ductility index and shear capacity were analyzed. The test results were compared with the shear design approaches of Chinese Code and American Code. The results indicate that the shear failure of beam with appropriate web reinforcement has finite ductility. High-strength concrete beams with high-strength stirrups can increase not only the shear capacity, but also the shear ductility. The shear capacity of beams with high-strength concrete and stirrup can be designed with Chinese Code, but shear capacity of high-strength concrete beams without stirrups, or with the smaller amount of longitudinal reinforcement, and normal strength concrete beams with high-strength stirrups may be over-estimated by the Code.
Wind Pressure and Wind-Induced Vibration of Heliostat
Authors: Wang Ying Ge , Li Zheng Nong , Gong Bo , Li Qiu Sheng
Published: March 2009

Heliostat is the key part of Solar Tower power station, which requires extremely high accuracy in use. But it’s sensitive to gust because of its light structure, so effect of wind load should be taken into account in design. Since structure of heliostat is unusual and different from common ones, experimental investigation on rigid heliostat model using technology of surface pressure mensuration to test 3-dimensional wind loads in wind tunnel was conducted. The paper illustrates distribution and characteristics of reflector’s mean and fluctuating wind pressure while wind direction angle varied from 0° to 180° and vertical angle varied from 0° to 90°. Moreover, a finite element model was constructed to perform calculation on wind-induced dynamic response. The results show that the wind load power spectral change rulers are influenced by longitudinal wind turbulence and vortex and are related with Strouhal number; the fluctuating wind pressures between face and back mainly appear positive correlation, and the correlation coefficients at longitudinal wind direction are smaller than those at lateral direction; the fluctuating wind pressures preferably agree with Gaussian distribution at smaller vertical angle and wind direction angle. The wind-induced response and its spectrums reveal that: when vertical angle is small, the background responsive values of reflector’s different parts are approximately similar; in addition, multi-phased resonant response occurring at the bottom. With the increase of , airflow separates at the near side and reunites at the other, as produces vortex which enhances dynamic response at the upper part.
Calculation of Short-Term and Long-Term Behavior of Prestressed Concrete Box Girders Considering Effect of Shear Lag
Authors: Hu Di , Wang Lai Fa , Guo Ji Ping
Published: March 2009

A set of formulae to calculate short-term behavior of simply supported prestressed concrete box girders under dead load and prestress are established based on energy method, in which shear lag and effect of prestressed steel and non-prestressed steel are taken into account. As the time-dependent relationship between stress and strain of concrete, equilibrium of sectional forces and compatibility equation are introduced, a novel approach to analyze long-term behavior of prestressed concrete box girders is presented, and the theoretical formulae considering the synthetic effect of creep and shrinkage of concrete, relaxation of prestressed steel, shear lag and restriction of steels are deduced, which can be used directly to calculate time-dependent deflection of box girder, stresses and strains of concrete and steel at any location at any time. Comparison of theoretical values shows that that the long-term deflection increases by shear lag while distribution of transverse concrete stresses become even by concrete creep and shrinkage.
High-Temperature Compressive Deformation of SiAlON Polycrystals Prepared without Additives
Authors: Chihara Kentarou , Hiratsuka Daisuke , Tatami Junichi , Wakai Fumihiro , Komeya Katsutoshi
Published: March 2009

The high-temperature deformation of dense nano-sized Ca-α SiAlON and submicron- sized β-SiAlON polycrystals were investigated by compression tests. These polycrystals were fabricated from Ca-α SiAlON and β-SiAlON nano powders respectively, and contained almost no intergranular glass phase. Both SiAlONs exhibited large plastic deformations with the stress exponent n ~1 in the higher stress region, and n ~2 in the lower stress region. Shear-thickening creep (n < 1), which has been reported in liquid contained SiAlONs, was not observed.
Dielectric Properties of SiAlON Ceramics
Authors: Kim Do Kyung , Kim Ha Neul , Seong Young Hoon , Baek Seung Soo , Kang Eul Son , Baek Yong Gi
Published: March 2009

The dielectric properties of -SiAlON and various cations doped -SiAlON bulk ceramics prepared by a hot-press method were investigated. The dielectric properties (dielectric constant and tangent loss) were characterized by a post-resonator method (Hakki-Coleman method) at room temperature in the microwave frequency range. The effect of z-values about -SiAlON was examined, and also the effects of various interstitial cations on dielectric properties of -SiAlON were studied. Dielectric properties of -SiAlON were compared with those of Si3N4 and -SiAlON and their relationship between the dielectric properties and the cationic species of SiAlON were discussed.
Synthesis and Characterization of β-SiAlON Phosphor Powder Prepared by Reduction Nitridation of a Zeolite
Authors: Wakihara Toru , Saito Yuri , Tatami Junichi , Komeya Katsutoshi , Meguro Takeshi , Fukuda Yumi , Matsuda Naotoshi , Asai Hironori
Published: March 2009

Rare-earth activated oxynitride or nitride luminescent materials have attracted considerable attention due to their potential applications as phosphors and pigments. Eu2+-doped -sialon has been reported to represent a new class of green phosphors with high efficiency. In this study, -sialon phosphor was synthesized by reduction nitridation of a zeolite. Eu ion-exchanged zeolite was fired at 1400 °C for 1 hour under NH3 gas containing 0.5 vol%C3H8. As a result, formation of -sialon with green emission under UV irradiation was confirmed.
Synthesis of Single-Phase, Hexagonal Plate-Like Al4SiC4 Powder
Authors: Lee Jin Seok , Nishimura Toshiyuki , Tanaka Hidehiko , Lee Sea Hoon
Published: March 2009

Single-phase and hexagonal plate-like Al4SiC4 powder was successfully synthesized using a mixture of Al(OH)3, SiO2 and carbon via a carbothermal reduction process. Two-step reaction was compartmentally observed during the calcination; the carbothermal reduction of SiO2 between 1300 and 1600oC and that of Al2O3 above 1500oC. The mechanisms which were responsible for the synthesis of the ternary carbide (Al4SiC4) powder were discussed.
Passive Oxidation Behavior of ZrB2-SiC Eutectic Composite Prepared by Arc Melting
Authors: Tu Rong , Hirayama Hideroni , Goto Takashi
Published: March 2009

ZrB2-SiC composites were prepared by arc melting using ZrB2 and -SiC powders as raw materials and their oxidation behavior were investigated. The eutectic composition of the ZrB2-SiC system was ZrB2-58.5mol%SiC and the melting point temperature was about 2570 K. At 1673 K mass gain was observed in the oxidation of ZrB2-SiC eutectic composition and the mass gain rate increased with decreasing Ptot. The oxide scale consisted of an amorphous SiO2 layer, a ZrO2-SiO2 eutectic-like layer and a Si-deficient layer.
Preparation of β SiAlON-cBN Composites by Spark Plasma Sintering
Authors: Hotta Mikinori , Goto Takashi
Published: March 2009

SiAlON-cubic boron nitride (cBN) composite was prepared by spark plasma sintering (SPS) using -SiAlON and cBN powders as starting materials, and the effect of holding time on densification, phase transformation and hardness of the composite was investigated. The SiAlON-cBN composite containing 20 vol% cBN sintered at 1650oC for 60s was densified to >97% of theoretical density. cBN phase transformed to hexagonal boron nitride (hBN) in the SiAlON-cBN composite with increasing holding time at 1650oC. Vickers hardness of the SiAlON-20vol%cBN composite sintered at 1650oC for 60-300s was 17.7GPa, and the hardness decreased with increasing holding time.
2.45 GHz Microwave Sintering of Silicon Nitride
Authors: Chockalingam S. , Kelly J.P. , Amarakoon V.R.W. , Varner James R.
Published: March 2009

Microwave sintered Si3N4-MgO system that contains 2, 4 and 10 wt% of ZrO2 as secondary particulates were investigated with respect to phase transformation and microstructure development. The experimental results of microwave sintered samples were compared with conventional methods. Complete α to β phase transformation was observed in the case of microwave sintered samples due to the volumetric nature of microwave heating. High temperature X-ray diffraction (HTXRD) analysis was performed to study in-situ the oxidation behavior of Si3N4 specimens. Si3N4 specimens with 10 wt % ZrO2 were exposed to air at temperature between 25°C and 900°C for up to 24 hours. Microwave sintered sample were structurally stable in air 25°C and 900°C for up to 24 hours of testing.
Fracture Resistance and Wear Properties of Silicon Nitride Ceramics
Authors: Miyazaki Hiroyuki , Hyuga Hideki , Yoshizawa Yuichi , Hirao Kiyoshi , Ohji Tatsuki
Published: March 2009

Six kinds of silicon nitrides with different microstructures were fabricated by changing the amount of sintering additives, Al2O3 and Y2O3. The hardness decreased with an increase in the amount of additives, whereas the indentation fracture resistance increased in the samples with large amount of additives due to the formation of coarse and elongated grains. The wear property of various Si3N4 ceramics was investigated in the sliding contact test without lubricant and was compared with the mechanical properties. The specific wear rate varied notably from 4x10-4 to 6x10-6 mm-3N-1m-1 depending on the compositions, which was difficult to explain directly from the hardness and fracture resistance. An indentation fracture model for material removal could correlate the wear properties with a function of hardness and fracture resistance of the materials, suggesting that the indentation model was likely to be valid for analyzing the wear behavior in this study.
Thinning Silicon Wafer with Polycrystalline Diamond Tools
Authors: Tso Pei Lum , Chen Cheng Huan
Published: March 2009

Sintered polycrystalline diamond (PCD) compacts are normally used for cutting tools, drill bits and wire dies. A novel application of PCD has been developed to use its entire surface carved to create different patterns which are triangle or square shape loaded with leveled millers that can shave brittle materials in ductile mode. Due to numerous cutting edges formed on the same level of PCD tools, which can be used to thin the wafer surface to achieve both flatness and smoothness of the industrial requirements. SEM has been used to observe the surface and subsurface of the thinned wafer surface. The critical depth of cut between ductile and brittle cutting mode is close to 2 µm in this thinning operation. The damaged layers of machined surface have been observed and studied in this paper.
Optimization of Cutting-Edge Truncation in Ductile-Mode Grinding of Optical Glass
Authors: Tamaki Junichi , Kubo Akihiko
Published: March 2009

The effect of cutting-edge truncation on the grinding mechanism of quartz glass as a hard and brittle material was investigated. From computer-aided grinding simulations and experiments on surface plunge grinding it was found that cutting-edge truncation decreases the ground-surface roughness and the maximum grain depth of cut; however, the maximum grain depth of cut approaches a constant value depending on the grinding wheel specifications. The alternative means of making the maximum grain depth of cut much smaller than this constant value is to increase the speed ratio. Cutting-edge truncation should be terminated at the optimum truncation depth to avoid the high grinding forces resulting from the flattening of cutting edges.
Synthesis and Property of New Poly-Acrylic Superplasticizer
Authors: Zheng Hong Wei , Wang Zhi , Qian Jue Shi , Shi Cong Li
Published: March 2009

According to design theory of molecular structure, a new poly-acrylic series superplasticizer PC-C with MPEG as graft side chain was designed, and was synthesized in water. The molecular structure of PC-C was shown by IR, the property of Poly-acrylic Superplasticzer was studied through methods of surface stress，dispersing property, slump maintenance and strength development. Experimental results showed that PC-C exerted low dosage，high dispersing property and dispersing retention property which improving with the increasing of dosage, and that PC-C has good adaptability with cement and strengthen efficiency to concrete.
Research on the Volume Stability of Ternary Cementitious Systems Incorporating Fly Ash and Slag Powder
Authors: Yang Hua Quan , Zhou Shi Hua , Dong Yun
Published: March 2009

The paper investigates the volume shrinkage of different cementitious materials. The results indicates the type and fineness of cement have significant effect on the volume stability of hardened paste, namely, the concrete with higher fineness cement has worse volume stability. The addition of mineral admixtures makes the volume stability of cementitious materials become complex. The mineral admixtures of high quality can reduce the shrinkage of hardened paste, and the duality system of cement incorporating fly ash have better volume stability than the ternary system of cement incorporating fly ash and slag powder.
Deterioration of Concrete Freezing-Thawing in Different Salts Solution
Authors: Ge Yong , Yang Wen Cui , Yuan Jie , Zhang Bao Sheng , Xiong Ai Ling
Published: March 2009

The frost resistance of concrete subjected to 3.5% NaCl solution, 5%, 7%, and 10% Na2SO4 solution and seawater were investigated by quick freeze-thaw test. There were two criteria, the relative dynamic modulus of elasticity (RDME) and the mass of scaling, for evaluating the frost resistance of concrete. The results showed that scaling was the main characteristic of deterioration when concrete subjected to freeze-thaw cycles in 3.5% NaCl solution and seawater, whereas RDME had little change. When freezing and thawing in Na2SO4 solution, concrete failed because of internal damage and surfaces of lower strength concrete specimens appeared local swelling and scaling before failure. Concentration of Na2SO4 solution had influence on frost resistance of concrete: deterioration of concrete in 5% or 7% Na2SO4 solution was severe but slower when the concentration reached to 10%. Entraining air into concrete was the best method to improve the durability of concrete subjected to freeze-thaw cycles in all solutions.