bluuebunny/crossref_metadata_2025 huggingface dataset:
A Novel Blue-Violet Emitting Mechanoluminescent Material with Calcium Aluminosilicate
Authors: Zhang Lin , Li Chen Shu , Yamada Hiroshi , Xu Chao Nan
Published: March 2009

We have demonstrated a novel blue-violet emitting mechanoluminscent(ML) material with calcium
aluminosilicate(CaAl2Si2O8:Eu2+). The ML was clearly visible to the naked eye in the atmosphere
and showed a similar spectrum to photoluminescence with a peak at 430nm. In order to enhance the
ML intensity, various rare earth ions were selected as co-dopants including La, Nd, Sm, Gd, Tb, Dy,
Ho, Er, Tm, Yb and Lu. It was found that the intensity of ML was strongly dependent on the kinds
of the codoped rare earth ion, especially the co-doping of Ho3+ was found to greatly enhance the
ML intensity. From the results of thermoluminescence(ThL) measurements, the enhancement of the
ML intensity was closely related with the filled trap concentration and trap depth.
Synthesis of Ba1-xSrxTiO3 Powders by KOH-KNO3 Molten Salt Method
Authors: Kishiki Tomohiko , Higuchi Masashi , Asaka Takashi , Azuma Yasuo , Katayama Keiichi
Published: March 2009

The synthesis of Ba0.5Sr0.5TiO3 (BST) powders was attempted using KOH-KNO3 molten salt. Single-phase BST powders could not be obtained when stoichiometric powders were regardless of the molten salt composition. Only when powders with excessive TiO2 were used, single-phase BST powders were obtained. The shape and aggregation state of the single-phase BST powder changed according to the heating temperature and the molten salt composition.
Effects of Lattice Defects on Cathode Properties of LiMn2O4 Synthesized at Low Temperatures for Lithium Ion Secondary Battery
Authors: Kaiya Hiroyuki , Suzuki Shinya , Miyayama Masaru
Published: March 2009

Effects of lattice defects on cathode properties of LiMn2O4 synthesized at low temperatures were
investigated. LiMn2O4 powders were synthesized by a sol-gel method. The specific capacities of
LiMn2O4 decreased from 134 to 81 mAh g-1 with decreasing heating temperature from 750 to 200°C.
X-ray absorption spectroscopy showed that a large amount of lattice defects such as cation
vacancies existed and cation mixing occurred in LiMn2O4 calcined at low temperatures. It was
found that the low specific capacities of LiMn2O4 calcined at low temperatures were attributed to
these lattice defects.
Electrode Properties of Ba0.5Sr0.5CoyFe1-yO3-δCathode Materials for Solid Oxide Fuel Cell
Authors: Asagi Shinya , Suzuki Shinya , Miyayama Masaru
Published: March 2009

The electrode properties of Ba0.5Sr0.5CoyFe1-yO3-δ {BSCF(5/5/10y/10(1-y))} on a Ce0.8Sm0.2O1.9
electrolyte were investigated. BSCF powders were synthesized by a solid-state reaction. The
electronic conductivities of BSCFs increased with increasing Co content and BSCF(5/5/8/2) showed
the highest conductivity of 38 S cm-1 at 600oC. The electrode resistance was measured on
symmetric cells, BSCF/Ce0.8Sm0.2O1.9/BSCF, over the temperature range from 600oC to 800oC. The
electrode resistances decreased with increasing Co content and BSCF(5/5/8/2) showed the lowest
electrode resistance in the whole temperature range, having an electrode resistance of 0.62 cm2 at
600oC.
Cutting Temperature Measurement in Turning with Actively Driven Rotary Tool
Authors: Harun Suryadiwansa , Shibasaka Toshiro , Moriwaki Toshimichi
Published: March 2009

In this paper, turning with actively driven rotary tool was investigated. The influence of
machining conditions such as tool rotational speed and inclination angle on the cutting edge
temperature is examined experimentally. The temperature was measured by a thermocouple of
constantan wire and work material. Experimental results show that the cutting temperature decreases
with increasing tool rotational speed to a minimum value at a certain tool rotational speed and then
increase. Next, the minimum temperature recorded by tool rotation was approximately 150oC lower
than that the cutting with a non-rotating tool. Finally, the cutting temperature also decreases with the
increase of inclination angle to a minimum value at an inclination angle.
A Study on Airflow Field of Super-High Speed Pectination Grinding Wheel Based on PIV
Authors: Gong Ya Dong , Zhang Yan Cheng , Li Hu , Wang Wan Shan
Published: March 2009

Adopting the method of PIV, systematical theory analysis and experiment research were
made on the airflow field distribution of super-high speed pectination grinding wheel, as well as
experiment design and data acquisition, the data processing was carried out through the software of
FlowMap, Tecplot, and Matlab. By analysis and discussion focused on experiment results, the general
rules of airflow field distribution in super-high speed pectination grinding wheel were preliminary
drawn, which provides the research foundation with a view to find a new method for the effective
supply of super-high speed grinding coolant.
The Possibility of Dressless Restoration of Grindactivity in Dry Grinding of Carbon
Authors: Ohashi Kazuhito , Sumimoto Y. , Fujita Y. , Hasegawa Hiroyuki , Tsukamoto Shinya
Published: March 2009

The grinding performance of wheel remarkably decreases by the loading of wheel surface
in dry grinding of hard carbon parts. In this report, we propose the removal method of loaded carbon
chips in which an adhesive tape is removed with carbon chips after putting on a loaded wheel surface
by an elastic roller with the setting load . The removal characteristics are experimentally investigated
by analyzing the projecting height of abrasive grains, removal force of adhesive tape and so on. The
removal method results in the enough projecting height of abrasive grain.
Study on Glass Strength at High Speed Edge Rounding for LCD
Authors: Suzuki Nobuyoshi , Halai Tatsunoli
Published: March 2009

With increasing in size of glass substrates for flat panel, both high productivity and high
quality are required for its edge rounding process. In order to understand the effect of process speed
on the strength of glass substrate, this study performs a profile grinding at the substrate edge with
varied feed rate. The obtained glass substrate then undergoes a four-point bending to evaluate its
strength. Weibull distribution is used to analyze the fracture strength of glass substrate after
edge-rounding process and to correlate the removal rate with the quality of the process.
Study on the Subsurface Damage of Single Crystal MgO Substrates
Authors: Dong Zhi Gang , Kang Ren Ke , Jia Zhen Yuan
Published: March 2009

Single crystal MgO can be used as the substrates to deposit HTS films. The subsurface damage (SSD) generated in processing has great effect on the strength and performance of the substrates. However, the characteristics of MgO SSD and its formation mechanism have not been understood fully. In this paper, the surface and subsurface damage caused by saw cutting, rough lapping and fine lapping of MgO substrates were studied by cross-section of microscopy and SEM. The formation mechanism was discussed; and a SSD model was presented.
Designing of Mechanical Structure and Translocating Clamp in Flexible Joint Stiffness Measuring System
Authors: Wang Hui Feng , Wang Guang Lin , Tao C.D. , Lu Ze Sheng
Published: March 2009

This paper analyzes the measure principle of flexible joint stiffness and constructs the
measuring system of flexible joint stiffness. It achieves the measurement of flexible joint’s
torque-rotation angle stiffness through designing the measuring appliance and translocating clamp.
The result shows that it is efficient to develop the measuring system and repeatability error is better
than 1%.
Research of Hydraulic Jack Leakage Diagnosis Emulation Base on Wavelet /AMEsim
Authors: Jing B.D. , Lu S. , Yang L.Z. , Wu H.
Published: March 2009

Researches the leak malfunction of hydraulic cylinder, which is the center typical part of
hydraulic pressure system. Use wavelet transform in detect the signal oddity aspect; the wavelet
transform can examine the mutation points such as saltation signal, pulse signal and the signal biggest
value etc. Tries to resolve leakiness breakdown the problem of the diagnosis in the new thinking.
Examining accurately a time difference of pressure ascension points can judge if there is leak or not
and severe degree of leak.It makes use of wavelet excellent zoom ability in space time and the
graphical development environment of AMEsim , constructs the system mold, imitates to really
analyze with dynamic state function, according to imitate a true result , the accuracy and the
possibility of wavelet analysis method in diagnosing the leak malfunction of hydraulic cylinder can be
got.
Green and Intelligent: Electromechanical-Hydraulic Integrated Clamping Device Based on Thermal Sensitive Material
Authors: Su D.N. , Zhong Kang Min , Dai X.L.
Published: March 2009

The fluid-driven clamping devices extensively used in the manufacturing industry nowadays are unable to adapt to the development requirements for green manufacturing technology owing to their low energy utilization, severe problems of noise and environment pollution. This article describes a clamping technology sparing the need of hydraulic pump and air compressor. It causes the thermal sensitive material to quickly expand or shrink linearly with the help of semiconductor heating/refrigeration conversion technology; then with the area effect stroke amplifier, the linear extension generated by the material is amplified around 100 times, and is output and passed to the clamping element in a linear motion manner to clamp the workpiece. This clamping device is an intelligent controlled electromechanical-hydraulic integrated system, featuring high energy utilization, extra low noise and fluid leakage etc.
Application of Wavelet Analysis in the Virtual Measurement of Roundness/Cylindricalness for Shaft-Like Components
Authors: Gu Li Zhi , Xiang Chun Jiang
Published: March 2009

Wavelet analysis was applied to detect the greatest deviation from the perfect circle for
the roundness and cylindricalness of shaft-like components in the virtual manufacturing engineering.
Based on the concepts of the roundness and cylindricalness, the least square method was adopted
into the determination of the reference—the least square circle from which the deviation was
calculated. In order to obtain the extremum of the errors, wavelet transform was carried out with
binary wavelet from the time domain to frequency domain. A virtual probe was used to have the
signals for the measured point by using WTnode_gettranslation() function. The accuracy of the
measurement depends, to a large extent, on the length of individual step along the axis and the
density of the measured points on the sections. Experiments have shown that the measuring
processing was time-saving and the results from the wavelet analysis were much reliable.
Hole Filling Algorithm in Surface Reconstruction Based on Radial Basis Function Neural Network
Authors: Wu X.M. , Li Gui Xian , Zhao W.M.
Published: March 2009

Aiming at hole filling in points cloud data reconstruction, a novel neural network
arithmetic was employed in abridged points cloud data surface reconstruction. Radial basis function
neural network and simulated annealing arithmetic was combined. Global optimization feature of
simulated annealing was employed to adjust the network weights, the arithmetic can keep the
network from getting into local minimum. MATLAB program was compiled, experiments on
abridged points cloud data have been done employing this arithmetic, the result shows that this
arithmetic can efficiently approach the surface with 10-4 mm error precision, and also the learning
speed is quick and hole filling algorithm is successful and the reconstruction surface is smooth.
Different methods have been employed to do surface reconstruction in comparison, the results
illustrate the error employed algorithmic proposed in the paper is little and converge speed is quick.
The Key Technology Research for Vision Inspecting Instrument of Steel Ball Surface Defect
Authors: Wang P. , Zhao Y.L. , Liu Xian Li , Wang Yi Wen
Published: March 2009

It has been necessary to adopting automatic detection of steel ball based on machine vision
in industrial processing. The detecting instrument for surface quality of steel ball based on machine
vision and embedded control technique and is applied to detecting external bug region of steel ball in
bearing. Its image detection and control system require excellent real-time character and high control
accuracy. This paper put forward a new design for image processing and control system of detecting
instrument. Firstly, we adopted OTSU segmentation arithmetic based on image enhancement and
median filtering. As a result, steel ball was detected by area character parameter. Secondly, we
adopted TMS320LF2407A as main processor and integrated CPLD to develop an embedded
controller. It presents a novel optimal design method for PID controller based on the ant colony
optimization (ACO) algorithm to optimize traditional PID control algorithm. At last, a performance
study of experimental system is conducted and it shows that the proposed method can be used in
online steel ball detection applications.
Research for Data Exchange Technology of Heterogeneous Database Based on XML
Authors: Wang Ya Ping , Ge Jiang Hua , Shao Jun Peng , Han S.T. , Li Zhi Qiang
Published: March 2009

Aim at an existent problems of manufacturing enterprise data exchange between design
and manufacturing software, this paper puts forward the solution of data exchange between
heterogeneous database with XML, which is based on the systematical analysis of currently data
exchange methods between heterogeneous databases, construct the data exchange model between
heterogeneous database based on XML. It gives mainly mapping method which is used for data
exchange between XML and relational database, and analyzes the algorithm of connecting relational
database, in order to solve the problem of transparently interoperation of heterogeneous database and
realize data integration and sharing between manufacturing enterprise heterogeneous database. So it
provides effective methods.
Finite Element Simulation of Orthogonal Cutting of Nodular Cast Iron
Authors: Zhang Sheng Wen , Gong Chan Yuan , Fang Xi Feng , Zhu C.S. , Jia W.
Published: March 2009

Some key techniques such as material constitutive model, friction characteristics at tool-chip interface were discussed. And the constitutive equation for nodular cast iron 500-7 was established. Then the simulation software DEFORM-2D was used to simulate the orthogonal cutting process. Finally, the influences of cutting parameters and tool geometries on cutting forces, cutting temperature and chip morphology were analyzed. This study provides some academic support to the optimization of cutting parameters for nodular cast irons.
Study on Integration of CAx/PDM Based on Web Services
Authors: Liu Yan Bing , Chen J. , Tong X.W.
Published: March 2009

Using the advantages of integration technique based on Web Services, a CAx/PDM integration framework was constructed to realize the integration of PDM and other application systems. With the framework, the encapsulation of PDM function modules based on .NET Framework was achieved, a dynamic integration method of PDM and CAx systems was provided, the middle format of exchanging data for PDM and other application systems was represented by the XML( Extensible Markup Language) schema to share the information of enterprise application systems. The proposed integration technology can be effectively used to CAx /PDM integration, and meets the manufacturing enterprise's requirement on integrating application system suitably.
Design and Development of Integrated System on CAD/CAE /CAPP for Tube-Bending in Power Plants Boiler
Authors: Lai Yi Nan , Ren Sheng Le , Yu Y.T.
Published: March 2009

Quality control is very important in the manufacturing process of cold tube-bending, but
most of enterprises can only verify tube quality by the tube bending machine. Based on the platform
of commercial software, an integrated system on CAD/CAPP/CAE for bending tube in power
plants boiler is developed. The system is carried on re-development under the VC++ language
environment, and data is transferred in Pro/E, Ansys and designing module through a reasonable
data structure and interface. So we can share data and realize flexibility and standardization of the
processing. The application result indicated that the integrated system can offer a whole set of
solution from building a CAD model, forecasting tube bending quality and structure optimization
by CAE methods to programming CAPP processes.
Boron Rich Boron Carbide: An Emerging High Performance Material
Authors: Mohanty R.M. , Balasubramanian K.
Published: March 2009

The focus of this research article is on the requirement, preparation and application of an improved material system composed of boron and carbon. These are known as boron rich boron carbides. The ability to form BRBC other than widely studied B4C composition through solid state reactive processes; hold an appeal owing to their potential for a variety of application in tribological, refractory, ballistic, nuclear energy, aerospace and other manufacturing industries. Study of the boron-carbon phase diagram, combined with the available literatures on ‘low yield’ vapor deposition processes and boron doping of B4C to prepare BRBC provided the impetus for this investigation on BRBC through solid state reactive processes, mainly micropyretic and plasma. This article summaries the ‘high yield’ experimental studies carried out for obtaining BRBC and their encouraging performance with respect to existing B4C composition based products.
Surface Resistance of Dispersion Ceramics against Third Body Abrasion
Authors: Oberbach Thomas , Begand Sabine , Kaddick Christian
Published: March 2009

Wear of the articulation partners in artificial joints for hip or knee is known to influence the in vivo survival rate of the implants. Wear amount can be strongly increased if third body wear occurs in the joint gap. Alumina ceramic is noted for a good wear resistance even under these worst case conditions. We tested the wear behaviour of the new dispersion ceramics ZTA (Zirconia Toughened Alumina) and ATZ (Alumina Toughened Zirconia) in comparison to alumina for the couplings ceramic on PE and ceramic on ceramic in a hip joint simulator in presence of third body particles.
In Vivo Evaluation of Porous Titanium Implants with Biomimetic Coating
Authors: Machado Ana Cristina P. , de Oliveira Marize Varella , Pereira Robson Pacheco , Carvalho Yasmin R. , Cairo Carlos Alberto Alves
Published: March 2009

The osseointegration of porous titanium implants was evaluated in the present work. Implants were fabricated from ASTM grade 2 titanium by a powder metallurgy method. Part of these implants were submitted to chemical and thermal treatment in order to deposit a biomimetic coating, aiming to evaluate its influence on the osseointegration of the implants. The implants were characterized by Scanning Electron Microscopy (SEM), Electron Dispersive X-Ray Spectroscopy (EDS) and Raman Spectroscopy. Three coated and three control (uncoated) implants were surgically inserted into thirty albino rabbits’ left and right tibiae, respectively. Tibiae samples were submitted to histological and histomorphometric analyses, utilizing SEM, optical microscopy and mechanical tests. EDS results indicated calcium (Ca) and phosphorous (P) at the surface and Raman spectra exhibited an intense peak, characteristic of hydroxyapatite (HA). Bone neoformation was detected at the bone-implant interface and inside the pores, including the central ones. The mean bone neoformation percentage in the coated implants was statistically higher at 15 days, compared to 30 and 45 days. The mechanical tests showed that coated implants presented higher resistance to displacement, especially after 30 and 45 days.
Preliminary In Vitro Biocompatibility of Injectable Calcium Ceramic-Polymer Composite Bone Cement
Authors: Puska Mervi , Korventausta Joni , Garoushi Sufyan , Seppälä Jukka , Vallittu Pekka K. , Aho Allan
Published: March 2009

In the coming decades, the need for reconstructive surgery of bones is predicted to increase with the ageing of the population as well as the increase of injuries needing traumatologic treatments. Therefore, there is still a constant search for tissue engineering and bone substitute materials. Xenografts, synthetic hydroxyapatitite, bioactive glasses and other bone substitutes have widely been studied. When bone defects are filled using bioceramics in granules, their utilization is limited to small size defects, because the injected granules do not give immediate support against the biomechanical loading of the bone. The aim of this study was to evaluate the preliminary biomineralization and the compression strength of experimental injectable bone cements modified with calcium ceramics. Our studies have focused on the development of injectable composites of bone cements, i.e. in situ curable resin systems containing impregnated Ca ceramics. The polymerized bone cement composites aspire to simulate as closely as possible the mechanical and structural properties properties of bone. The present compressive strength of our inorganic-organic bone cements are >65 up to ~180 MPa. These cements are slightly porous from their outermost surface and showed preliminarily osteoconductivity of some degree.
Characterization of CaP Coating Deposited on Porous Titanium
Authors: Silva de Medeiros Waléria , Pereira Luiz Carlos , Pereira Robson Pacheco , de Oliveira Marize Varella
Published: March 2009

Synthetic Hydroxyapatite (HA) has been used as coating in order to enhance biocompatibility of titanium implants. Osseointegration at the implant-bone interface can be positively affected by the presence of HA coating and other biocompatible calcium phosphates (CaP) deposited on titanium implants, due to the high biocompatibility of these bioceramics. The biomimetic process is based on the nucleation and growth of a bioceramic film onto a substrate immersed in a body fluid solution (SBF) and it can be applied to deposit CaP coatings onto metallic substrates. The present work presents results on the characterization by SEM of CaP coating deposited on porous titanium samples by a biomimetic process.
In Vitro Assessment of Hydroxyapatite and Si-Substituted Hydroxyapatite Coatings under Different VPS Conditions
Authors: Tang Qian , Brooks Roger , Best Serena
Published: March 2009

Hydroxyapatite and silicon-substituted hydroxyapatite powers were prepared in-house through a wet precipitation method and then vacuum plasma sprayed onto Ti-6Al-4V discs. Two plasma gun input powers were employed, 37 kW and 40 kW. All coatings were nearly phase pure, except small traces of impurities (TTCP, -TCP and CaO). Coatings prepared under the lower plasma gun input power had lower crystallinity. In vitro studies showed that human osteoblast-like cells attached and spread very well on all coated discs. Among the four kinds of discs, SiHAC37 was the most supportive to cell growth.
Surface Analysis and Cell Biology Technique in Understanding Degradation of Natural Temporary Teeth Collected from an Area with High Pollution
Authors: Demetrescu Ioana , Iordachescu D. , Ionita D. , Manea Stef
Published: March 2009

The aim of this paper is to correlate surface features of degraded temporary teeth from area with high pollution with the cell adhesion and proliferation. Viability of gingival fibroblast (HGF-1, CRL-2014, American Type Culture Collection) was evaluated with a MTT (3-(4,5-dimetiltiazol-2-il)-2,5-difeniltetrazolium bromide ) test and the values are discussed for the most degraded temporary teeth in correlation with the change in surface morphology and hydrophilic/hydrophobic balance, taking into account that cell adhesion is related to a more hydrophilic character.
Surface Reaction of Titanium Oxide Film to Fluoride and Hydrogen Peroxide in Simulated Oral Environment
Authors: Takemoto Shinji , Hattori Masayuki , Yoshinari Masao , Kawada Eiji , Oda Yutaka
Published: March 2009

When titanium and titanium alloys are used in prosthodontic devices, exposure to the oral environment may result in discoloration or corrosion. This phenomenon may be due to fluoride, found in prophylactic agents, or peroxide, which is either produced by inflammatory cells or present in denture cleaning agents. The aims of this study were to clarify the process of discoloration or corrosion of titanium in an oral environment, and investigate the reaction of surface titanium oxide to fluoride and hydrogen peroxide by analysis of electrochemical behavior and X-ray photoelectron spectroscopy. Surface oxide film on commercially pure titanium (CP-Ti) in fluoride-containing solution was dissolved and corroded. In the peroxide-containing solution, a gradual development and thickening of the surface oxide film with subsequent discoloration of the titanium was observed
Development of Gelatin/HA Membranes
Authors: de Oliveira Vercik Luci Cristina , Vercik A. , Bressiani José Carlos
Published: March 2009

The aim of this work is to develop membranes of gelatin/hydorxyapatite composite for using as mechanical barrier. Membranes with 4% of gelatin and 0.5-3% of hydroxyapatite were studied. The composite was obtained by heterogeneous co-precipitation method. X-ray diffractometry showed the formation of a pure phase of hydroxyapatite with excellent crystallinity. Using atomic force microscopy, the distribution of crystals of hydroxyapatite in the gelatin matrix was observed, with nanoparticles of about 50-100nm in a homogeneous mixture. After crosslinking process with glutaraldehyde at different concentrations (0.5, 1, 1.5 and 2%), a significant decrease of the swelling behavior was observed due to the increase of the amount of triple helix in the samples, which increases their stability in aqueous solution.
PLGA-Hydroxyapatite Composite Scaffolds for Osteoblastic-Like Cells
Authors: Dutra Messias André , Aragones Aguedo , Aparecida de Rezende Duek Eliana
Published: March 2009

The aim of this work was to investigate the behaviour of rat calvarial osteoblastics cells on porous PLGA/HA composite scaffolds. Cells were submitted to cytotoxicity and cell adhesion assay. In addition, the cells morphology were observed by SEM, and the collagen synthesis measured by Sirius Red colorimetric method. The results showed that the material was not cytotoxic and hydroxyapatite improved cell adhesion. Osteoblastic cells could adhere and spread on the scaffolds as observed. After 14 days the presence of hydroxyapatite increased the synthesis of collagen. This study demonstrates that composite scaffolds presented better cellular responses compared to polymer scaffolds.
Synthesis and Biocompatibility of Hydroxyapatite in a Graphite Oxide Matrix
Authors: Rodríguez-Lorenzo Luis M. , Benito-Garzón Lorena , Barroso-Bujans Fabienne , Fernández Mar
Published: March 2009

Though hydroxyapatite has the ability to promote bone growing, devices based on OHAp are mechanically weak and need to be reinforced for load bearing applications or in the manufacturing of scaffolds for bone regeneration. Graphite (Gr) could provide appropriate reinforcement properties to OHAp without being deleterious for the biocompatibility of the system. This paper describes an accelerated synthesis of the OHAp with ultrasonic agitation in the presence of functionalized graphite (GO). The toxicity of the Graphite and the GO-OHAp system is evaluated. GO-OHAp was produced by a wet chemical reaction involving CaCl2 and Na2HPO4. The calcium salt solution was added first and the solution sonicated for 1 hour, before repeating the operation with the phosphate solution. Biocompatibility was tested by using a primary cell culture of HOB (ECCAC). The disappearance of the maximum at 2q = 26.32º corresponding to the d002 plane of graphite and the appearance of the maximum at 2q = 13.2º in the XRD patterns is related with an expansion of the grapheme sheets from 0.34 nm to 0.59 nm and it has been used to assess the graphite oxidation. The OHAP on GO growing has been confirmed by the appearance of a broad peak centred at 2q = 31.5º and a sharpened peak at 2q = 26.0º characteristic of low crystalline apatites. Although the employed graphite can be considered biocompatible, cellular viability is significantly improved by the presence of apatite.
The Relationship of the Oxide Phases on Irradiated Titanium Surface by Nd:YVO4 Laser with the Ca,P Deposited Layer
Authors: Braga F.J.C.
Published: March 2009

he scope of this paper is focused on surface modification process by laser beam irradiation in pure metallic titanium inducing by ablation phenomenon such non stable oxides formation on the irradiated surface. The present study correlates the pulsed laser beam parameter conditions used to irradiate pure metallic titanium and its resulting crystalline phases on the surface with the deposited calcium phosphate layer on it.
In Vitro and In Vivo Evaluation of Bioactive Glass/PVA Porous Hybrids for Application in Bone Reconstruction
Authors: Gomide Viviane , Ocarino Natália , Serakides Rogéria , de Fatima Leite Maria , Pereira Marivalda
Published: March 2009

Bioactive glass/polymer hybrids are promising materials for biomedical applications because they combine the bioactivity of these bioceramics with the flexibility of polymers. In previous work hybrid foams with 50% bioactive glass and 50% polyvinyl alcohol (PVA) were prepared by the sol-gel process for application as scaffold for bone tissue engineering. In this work the hybrid samples were tested in osteoblast culture to evaluate adhesion and proliferation. Samples were also implanted subcutaneously in the dorsal region of adult rats. The hybrid 50% PVA/bioactive glass foam was chosen as the best scaffold in the composition range studied and it is a promising material for bone repair, providing a good environment for the adhesion and proliferation of osteoblasts in vitro. Concerning the in vivo studies we can assure that the “foreing body” reaction was moderate and that the presence of osteoid indicated bone matrix formation.
Manufacturing of Porous Alumina Scaffolds with Bio-Glass and HAp Coating: Mechanical and In Vitro Evaluation
Authors: Camilo Claudia C. , Fortulan C.A. , Ikegami R.A. , Santos Arnaldo R. , de M. Purquerio B.
Published: March 2009

The objective of this study was to manufacture porous scaffolds with bioinert and bioactive materials to join mechanical properties and bony integration. Porous alumina ceramic matrices were produced using the slurry technique followed by isostatic pressing, leaching and sintering. Porous alumina samples presented 75.0vol% porosity and 52.27MPa of compressive strength. Bioglass/hydroxyapatite ceramic slurry was used as coating on alumina matrices. The infiltration was performed by dipping the alumina porous samples into bio-glass/hydroxyapatite ceramics slurry under vacuum and followed by sintering. The evaluation of the alumina ceramic scaffolds samples were made using EDX, mechanical and in vitro tests. For the in vitro tests, fibroblastic VERO cell line was employed. The porous alumina ceramic coated acquired a higher strength and more pronounced cell interaction than the non coated alumina scaffolds.
The Importance of Osteoclast-Like Multinucleated Cells in Material-Induced Osteoinduction: A Comparative Study between Dogs and Rats
Authors: Akiyama Norihiro , Takemoto Mitsuru , Fujibayashi Shunsuke , Neo Masashi , Hirano Masahiro , Nakamura Takashi
Published: March 2009

Material-induced osteoinduction has been reported in comparatively large animals such as dogs and pigs; however, it does not often occur in small animals such as rodents. In this study, we implanted the porous calcium-deficient hydroxyapatite (CDHA) in the dorsal muscles of dogs and rats, and compared cellular events occurred in 2 species with particular emphasis on the osteoclast-like multinucleated cells. In the CDHA extracted from dogs, many tartrate resistant acid phosphatase (TRAP)-positive multinucleated cells were detected after 2 weeks, and new bone formation was observed after 4 weeks. In contrast, in rats, only a small number of TRAP-positive cells were detected and no bone formation was observed before 6 weeks. Transmission electron microscopy (TEM) revealed that multinucleated cells in the CDHA from dogs after 2 weeks showed osteoclast-like structures such as ruffled borders. However, in the CDHA from rats, there were no osteoclast-like structures observed. Reverse transcription-polymerase chain reaction (RT-PCR) revealed that the expression of cathepsin K in dogs was higher than that in rats. These results indicate that TRAP-positive cells might be one of main factors responsible for the cross-species difference in material-induced osteoinduction.
The Surface Property of Hydroxyapatite: Sensing with Quartz Crystal Microbalance
Authors: Ikoma Toshiyuki , Tagaya Motohiro , Tonegawa Toru , Okuda Mitsuhiro , Hanagata Nobutaka , Yoshioka Tomohiko , Chakarov Dinko , Kasemo B. , Tanaka M.
Published: March 2009

Hydroxyapatite (HAp) sensor, available for quartz crystal microbalance with dissipation (QCM-D) technique, has been fabricated by an electrophoretic deposition method. The method of re-usability of the sensor after adsorption of fibrinogen and the biological apatite (BAp) growth on the sensor with and without the adsorption of feral bovine serum (FBS) from 1.5 simulated body fluid were investigated. The re-usability of the sensor, cleaning with the combination of ammonia and hydrogen peroxide mixture and UV/ozone treatment, achieved ten times reuses. BAp was grown on the HAp surface but not on the gold surface at 37.5 oC for 40 hours. The viscoelastic property (DD/Df value) of the BAp layer on the HAp sensor showed harder than that of the protein adsorption films from FBS. The amount of the BAp grown on the HAp sensor adsorbed FBS is lower than that on the HAp sensor. The adsorption of FBS proteins on the HAp surface strongly inhibited the BAp growth.
Biomass Ash in Concrete-Mitigation of Alkali Silica Reactions (ASRs) — Expansions with Different Opal Percentages
Authors: Wang Shuang Zhen , Baxter Larry
Published: March 2009

ASTM (American Standard Testing and Materials) C 618 prohibits use of biomass ash in concrete. This paper systematically investigates mitigation of Alkali Silica Reaction (ASR) expansion of concrete by three biomass ashes (cement: biomass ash = 65: 35 by weight), and the ASR expansion is triggered by high alkali cement and opal (1-9% weight of quartz replacement). The three biomass ashes come from switchgrass or sawdust cofired with Powder River Basin coal and they cut the ASR expansion significantly below 50% of the control level; however, all three biomass ashes doubled the available alkali of the cement they replaced. Therefore, the exclusion of biomass ash in concrete by ASTM C 618 seems impropriate and more quality research on its role in mitigating ASRs expansion should be conducted.
Water Repellent Treatment on Lime/Lime-Fly Ash/Lime-Cement Mortar with and without Carbonation
Authors: Zhang Peng , Scherer T. , Zhao Tie Jun , Wittmann F.H.
Published: March 2009

Water repellent treatment (WRT) has proved to be effective to prevent porous materials from water penetration and consequently can improve the durability of structures. In this contribution, three types of mortar, which are pre-carbonated and non-carbonated, had been water repellent treated by silane gel with usage of 400 g/m2, to investigate into the influence of WRT on carbonated and non-carbonated mortar. Results indicate that carbonation reaction increased the compressive strength of all three types of mortar. Silane gel penetrated to a comparatively higher depth for the carbonated mortar. WRT reduced the absorbed water and capillary absorption coefficient greatly, both for non-carbonated mortar to 2 % ~ 7 % and for carbonated mortar to 22 % ~ 66 %, compared with non-treated ones. WRT is still a feasible method for porous materials with some carbonation to prevent from water penetration. However, the efficiency of WRT on reducing capillary absorption became much lower compared with the non-carbonated mortar. Capillary absorption curves of non-WRT mortar, both carbonated and non-carbonated, could be well fitted by a hyperbolic function of square root of time. For the treated mortar, the absorption curves could be described as a linear equation before carbonation, but an exponential function when the mortar carbonated.
Rheology of Mortar and its Influences on Performance of Self-Consolidating Concrete
Authors: Ng I.Y.T. , Ng P.L. , Kwan A.K.H.
Published: March 2009

A two-part experimental program is presented in this paper. In the first part, four self-consolidating mortar mixes were designed with different compositions of cementitious materials including cement, pulverized fuel ash and condensed silica fume. For each SCM mix composition, the superplasticizer dosage was varied and a total of 30 batches of mortar were produced. For every batch of mortar, the rheology was determined by a rheometer and the workability was measured by the mini slump flow test and the mini V-funnel test. From the test results, the saturation SP dosage of each SCM mix was determined. In the second part, four self-consolidating concrete mixes were produced, each comprising a SCM mix with saturation SP dosage and a fixed coarse aggregate content. The workability, filling and passing abilities and segregation stability were measured by the slump flow, U-box and sieve segregation tests, respectively. It was found that the performance of all the SCC mixes was satisfactory. The test results suggested that using a SCM mix with saturation SP dosage as the mortar phase can produce SCC with high performance and therefore is a good starting point to optimize the performance of SCC mixes.
Rapid Repair of Earthquake Damaged RC Interior Beam-Wide Column Joints and Beam-Wall Joints Using FRP Composites
Authors: Li Bing , Chua H.Y.Grace
Published: March 2009

This paper studies the seismic performance of FRP-strengthened RC interior non-seismically detailed beam-wide column and beam-wall joints after limited seismic damage. Four eccentric and concentric beam-wide column joints and two beam-wall joints, initially damaged in a previous study, were repaired and tested under constant axial loads (0.1 and 0.35 ) and lateral cyclic loading. The rapid repair technique developed, aimed to restore the original strength and to provide minimum drift capacity. The repair schemes were characterized by the use of : 1) epoxy injection and polymer modified cementitious mortar to seal the cracks and replace spalled concrete and 2) glass (GFRP) and carbon (CFRP) sheets to enhance the joint performance. The FRP sheets were effectively prevented against possible debonding through the use of fiber anchors. Comparison between responses of specimens before and after repair clearly indicated reasonable restoration in strength, drift capacity, stiffness and cumulative energy dissipation capacity. All specimens failed with delamination of FRP sheets at beam-column joint interfaces. The rapid repair technique developed in this study is recommended for mass upgrading or repair of earthquake damaged beam-column joints.
Fragility Analysis Method for Vertically Irregular Reinforced Concrete Frame Structures
Authors: Men Jin Jie , Zhou Qi , Shi Qing Xuan
Published: March 2009

This paper concentrates on the fragility analysis method for vertically plan reinforced concrete frame structures. The weakness story inter-story drift ratio is selected as the fragility variable for vertically plan structures. Five states are established to distinguish the structural seismic performance levels, which are expressed with inter-story drift ratio. Then through the nonlinear dynamic analysis and linear regress, the exceeding probability function of seismic response is obtained and a new fragility analysis method is put forward for vertically irregular frame structures. Two kind of unit models, two kind of hysteretic models and forty earthquake records are chosen to established structure-earthquake system samples. Thus one hundred and twenty structure-earthquake system samples are obtained for irregular reinforced concrete frame, which take into account the uncertainty of member materials, structures systems, numerical simulation models and earthquake motions adequately. Then example is presented to demonstrate the applicability and utility of the proposed methodology. Seismic performances of a vertically irregular reinforced concrete frame structure are evaluated in detail. It is concluded that fragility curves are more abrupt in low input earthquake motion intensity and they are influenced much by the structural performance levels.
The Key Technology of Skew Continuous Prestressed Concrete Box Girder Bridges with Incremental Launching Method
Authors: Tian Zhong Chu , Zeng Guo Liang , Chen Min , Yue Hai Ling
Published: March 2009

Incremental launching method is a construction technology for prestressed concrete continuous bridges widely used in China. In the incremental launching method, the superstructure of a bridge is erected from one side of bridge longitudinally to the opposite bank. Compared with other technology for bridge erection methods, it may reduce the cost of labor, shorten the construction period and save the assembly yard. So it is a competitive construction method for medium-span prestressed concrete continuous bridges. A large number of skew bridges will be built especially at mountain area, so it is very necessary to research on incrementally launching method for skew bridges. The objective of the study presented in this paper is to introduce the method used in the Lishui Bridge in Zhangjiajie city of China.
Smart Concrete, Sensors and Self-Sensing Concrete Structures
Authors: Li Hui , Ou Jin Ping
Published: March 2009

Smart concrete technology provides a new alternative way for health monitoring of reinforced concrete structures. In this paper, the piezoresistivity of two kinds of smart concrete filled with carbon black or carbon fiber was studied, and two types of embedded sensors were fabricated using the smart concrete with favorable piezoresistivity. The sensing performance, the measuring methods and the response to environmental temperature and humidity of embedded sensors were investigated. A compensation circuit was incorporated to reduce the effect of temperature and humidity on the output of embedded sensors. The sensors were embedded in concrete beams and columns to monitor the structural compressive strain under field conditions. Experimental results indicate that the embedded sensors fabricated using smart concrete filled with carbon black or carbon fiber feature favorable sensing performance (gauge factors are 55.28 and 138 respectively). The self-sensing concrete components embedded with these sensors can realize the monitoring of their local compressive strain. It therefore can be concluded that the prepared smart concrete and the developed embedded sensors have great potential to be used for health monitoring and damage assessment of concrete structures.
Investigation of the Axial Bearing Capacity of the Discontinuous-Tube-in-Core Concrete Filled Steel Tubular Column-Slab Joint
Authors: Liu Fu Jun , Cai Jian
Published: March 2009

Based on the principle of restrained concrete, this paper presents a new-type concrete filled steel tubular column-slab joint. This new-type joint is characterized by keeping the concrete floor slab continuous while breaking the steel tube of the column for the joint, thus joining the slab and the concrete filled steel tubular(CFST) columns at the top and the bottom of the slab. The joint has the advantage of transferring loads dependably, constructing conveniently and saving on the cost. Three groups of experiments (21 specimens contained) were performed to test the safety of the joint and investigate its axial bearing capacity. The results show that the joint is dependable and feasible in engineering applications. In addition, this paper studies the working mechanism and mechanical properties of the joint under axial compression, discusses the factors to influence its axial bearing capacity, and finally brings out the formula of the joint’s bearing capacity under axial compression that adapts to engineering applications, which conservatively evaluate the result of the experiments.
Effects of Process on Optical Transmittance of Dy-α-Sialon Sintered at Lower Temperatures
Authors: Xue Jun Ming , Liu Qian , Fang Ming , Ma Li Li , Xiu Tong Ping , Gui Lin Hua
Published: March 2009

In order to prepare translucent sialon more easily, LiF was used as a non-oxide sintering additive to lower the sintering temperature to ≤1650 °C. The present work shows that the sintering process has a strong effect on microstructure and property of α-sialon.
In Situ Synthesis and Mechanical Properties of TiN-Si2N2O-Si3N4 Composites
Authors: Kiyono Hajime , Shimada Shiro
Published: March 2009

Si3N4-Si2N2O-TiN composite ceramics were in-situ fabricated by using following reactions of (1) 3TiO2 + Si3N4 → 3TiN + 3SiO2 + N2 and (2) Si3N4+ SiO2 → 2Si2N2O. The mixed powder of α-Si3N4, Al2O3, Y2O3 and TiO2 was hot-pressed at 24 MPa and 1800°-1900°C for 1-4 h in N2. Sintered composite ceramics were characterized by XRD, SEM, TEM, four-point bending test and Vickers indentation method. XRD results and TEM observation showed that TiN and amorphous SiO2 were formed at 1250°C by the reaction (1), and the Si2N2O phase formed by reaction (2) above 1800°C. Si3N4-Si2N2O-TiN composites consisted of ≥2 m sized Si2N2O grains with TiN and Si3N4 grains. Hardness and fracture strength of the composites were comparable to those of Si2N2O ceramics, with fracture toughness being improved at 5vol% TiN containing composites.
Mechanical and Thermal Properties of Silicon Carbide Composites with Chopped Si-Al-C Fiber Addition
Authors: Itatani Kiyoshi , Davies Ian J. , Suemasu Hiroshi
Published: March 2009

The fabrication conditions of dense silicon carbide (SiC) composites containing chopped Tyranno Si-Al-C (SA) fiber were examined in this work; SiC compacts containing SA fiber (mean lengths: 214, 394 and 706 m) were hot-pressed at 1800°C for 30 min under a pressure of 31 MPa in Ar atmosphere. The fracture toughness of SiC composites with 40 mass% of SA fiber addition (sintering aid: 5 mol% Al4C3) increased from 2.8 up to 4.7 MPa•m1/2 as the fiber length increased from 214 to 706 m. The enhanced fracture toughness of the SiC composites was attributed to the lowering of fiber orientation angle (i.e., the angle between the fiber length and direction perpendicular to the hot-pressing direction) to 5° with increasing fiber length. The fracture toughness of SiC composites could be further enhanced through the incorporation of SA fibers with a carbon interface (thickness: 100 nm) into the SiC matrix. The fracture toughness of SiC composite containing 40 mass% of these fibers attained 6.0 MPa•m1/2. The thermal conductivity of SiC composites increased with fiber length from 30.5 W•m-1•K-1 to 45.5 W•m-1•K-1; with no significant influence being noted for the case of fibers with a carbon interface.
Non-Oxide Ceramic Nanocomposites with Multifunctionality
Authors: Kusunose Takafumi , Sekino Tohru
Published: March 2009

Two types of Aluminum nitride (AlN) based ceramic nanocomposite with multifunctionality were investigated to improve machinability or electrical conductivity of AlN ceramics with high thermal conductivity. The AlN/BN nanocomposite was fabricated by hot-pressing AlN-BN composite powder, which was prepared by reducing and heating AlN particles containing a mixture of boric acid, urea and carbon. The nanocomposite containing 20 vol.% BN showed high strength, good machinability and relatively high thermal conductivity. On the other hand, the sintered AlN ceramics with CeO2 as an additive indicated high thermal conductivity and electric conductivity which is possible for electric discharge machining.