bluuebunny/crossref_metadata_2025 huggingface dataset:
The Rolling Contact Fatigue Wear of Nylon Composites Filled with Metal-Oxides
Authors: Ge Shi Rong , Huang Chuan Hui
Published: March 2009

The fatigue wear behavior of PA1010 composites filled with metal oxide particles was
experimentally investigated. The nylon composites were prepared by compression molding method
with different contents of PA1010 and CuO, Fe3O4, Al2O3 particles. The rolling contact counterpart
for nylon composite samples was 1045 carbon steel ring. The rolling contact tests were performed
on M-2000 wear test machine in dry friction condition. It was found that the fatigue wear measured
in mass loss of nylon composites increases to rolling contact cycles. Most of the samples show an
approximately linear relationship between wear mass loss and rolling cycles. Three kinds of metal
oxide particles have different effects on the fatigue wear behavior of nylon composites. The
contents of metal oxide particles have important influence on the fatigue wear behavior. The nylon
composites filled with CuO (30 wt.%) or Fe2O3 (30 wt.%) will result in the comparatively highest
wear resistance, the wear mass loss reduces to about 70% of pure nylon. Al2O3 particles is not a
good choice for increasing the rolling wear resistance of nylon composites. It is found that the
contact fatigue controls the wear mechanism of nylon composites under rolling contact.
Tribological Behavior of Laser-Cladding Ni60 and Co-Cr-W Coatings at Elevated Temperature
Authors: Cai Zhen Bing , Zhu Min Hao , Lin Xiu Zhou , Mo Ji Liang , Zhou Zhong Rong
Published: March 2009

Nickel base Ni60 and cobalt base Co-Cr-W coatings were prepared on substrate of
refractory alloy steel 4Cr14NiW2Mo by laser-cladding technology. A 2 kW transverse-flowing CO2
laser device was used for cladding alloy powder. Another Co-Cr-W coating was formed by bead
welding. Under room temperature, 250 oC.and 420 oC, reciprocate sliding wear tests with a
ball-on-flat contact for three coatings have been carried out. For the laser cladding coating, a good
metallurgical bonding with the substrate was obtained. Different tribological behaviors of three
coatings were observed. For the two Co-Cr-W coatings, the friction coefficients decreased with the
increase of test temperature, and larger spot-like stripping pit and wider ploughing trenches in the
wear scars were presented. The wear mechanism was the combination of abrasive wear,
delamination and oxidation wear. For the Ni60 laser cladding layer, the friction coefficient hardly
changed with the elevated temperature, and the wear mechanism mainly performed as abrasive wear
due to its high oxidation resistance. The wear tests showed that the Ni60 clad coating had provided
excellent wear resistance than Co-Cr-W layers under high temperature reciprocating sliding wear
condition.
The Contact Resistance and Arc Erosion Behavior of Separable CP-Nb-Cr/Cu-Cd Electrical Contact Material
Authors: Cui Yu Sheng , Zhen Liang , Wang Y. , Shao Wen Zhu , Ivanov V.V.
Published: March 2009

CP-Nb-Cr/Cu-Cd electrical contact material, which contains 1.7wt.% of Cd, 0.5wt.% of CP
(man-made diamond particles), 2.0 wt.% of Nb and 0.7 wt.% of Cr, was fabricated by powder
metallurgy process. The contact material was installed in different ac contactors covering current
range from 40 to 630A. While tested under AC-4 electrical load, the electrical contact material was
worn out gradually by repeated electrical arc, and microstructure of the arc-affected surface layer
changed dramatically. Mechanism of arc erosion process and contact resistance fluctuation was
discussed by corresponding microstructure observation and chemical composition analysis of the
surface layer. CP-Nb-Cr/Cu-Cd electrical contact material is capable to be used in 63~250A ac
contactors under AC-4 working conditions.
Sliding and Loosening Behavior of Thread Joints under Transverse Loading
Authors: Nishimura Naoya , Hattori Toshio , Yamashita Minoru , Hayakawa Naoyuki
Published: March 2009

In this paper, we have evaluated the sliding and the loosening behavior of thread joints
under transverse loading. Firstly, the critical relative slippage (Scr), less than which the thread joints
can keep the fastening, is obtained by the cyclic loading tests. Then, this critical relative slippage is
estimated according to the theoretically obtained equation considering the bending deformation of
bolt and the geometrical constraint condition. The inclination compliance (kw) of the bolt head used
in this equation is evaluated by comparing the experimental result with the corresponding analytical
one. In consideration of the nonlinearity of kw with respect to the bolt axial tension, the Scr is well
estimated by this equation.
Study on Dynamic Behaviors of Thin Plate Structure by DBEM
Authors: Fang Ying Wu , Wu De Wei , Lu Yan Jun , Lei Zhi Xiong , Wang Yi
Published: March 2009

An analytical method of single field reducing-coupling on dynamic modeling is presented
to analyze dynamic behaviors of thin plate structure based on dynamic fundamental solutions. In order
to improve systematic modeling precision and efficiency, the method of single field
reducing-coupling is introduced to deduce governing equations of thin plate structure dynamics by
dynamic boundary element method (DBEM). The scale of matrix and generated time of coefficient
matrixes are shortened greatly and dynamic behaviors of thin plate structure is obtained rapidly and
accurately. The numerical examples and experiments show that the theory, established method and
calculating program are feasible, and it has good precision and high efficiency.
Mechanism of Brittle-Ductile Transition of Single Silicon Wafer at Different Temperatures
Authors: Sun Yu Li , Zuo Dun Wen , Zhu Yong Wei , Li Duo Sheng , Qi Mei , Wang Min
Published: March 2009

Formation, propagation and length of crack and hardness of single silicon wafer were investigated at different temperatures by means of Vickers indentation, using lower temperature testing unit with semiconductor refrigerating chip and higher temperature testing unit with closed electric furnace. The results show that the hardness of single silicon wafer decreases with the increase of temperature, while the length of crack increases with the increase of temperature. Ductile-brittle transition of the single silicon wafer can occur at different temperatures with the increase of load. When the load is smaller and temperature is lower, no cracks can be found.
Thermal Study in Diamond Grinding of Zirconia
Authors: Shen Jian Yun , You Fang Yi , Xu Xi Peng
Published: March 2009

In the present study, zirconia ceramic was ground with a resin-bonded diamond wheel on a precision surface grinding machine. Grinding temperatures generated at the wheel-workpiece contact zone were measured using a sandwiched foil thermocouple, and the net consumed grinding powers were also measured. The energy partition to the diamond abrasives was estimated using measured grinding temperatures and powers. Based on the energy partition values obtained from the analyzed results, the diamond tip temperature was calculated and found to be over 1000°C if the circular grain contact of radius was less than a critical value for ductile field grinding of zirconia ceramic.
Surface and Sub-Surface Integrity of Ultra- Machined BK7 Using Fine and Coarse Grained Diamond Wheels
Authors: Zhao Qing Liang , Wang Bo , Brinksmeier Ekkard , Riemer Otmann , Rickens Kai , Corbett John
Published: March 2009

This paper aims to evaluate the surface and sub-surface integrity of optical glasses which were correspondingly machined by coarse and fine-grained diamond grinding wheels on Tetraform ‘C’ and Nanotech 500FG. The experimental results show that coarse-grained diamond grinding wheels are capable of ductile grinding of optical glasses with high surface and sub-surface integrity. The surface roughness values are all in nanometer scale and the sub-surface damages are around several micros in depth, which is comparative to those machined by fine-grained diamond wheels.
Experimental Study of Precision Polishing of Hard and Brittle Material
Authors: Dong Li Hua , Fan Chun Hua , Huang Jian , Luo Hong Xia
Published: March 2009

The application of hard and brittle materials become wider and wider because its self-characteristics. It is used widely in finish machining of products, such as memory record device, information products, precision instrument, etc. Traditional grinding-polishing methods have not suited for precision machining requirements of hard and brittle materials. Carbide and ceramic are chosen as workpiece. Diamond polishing film is chosen as polishing tool. Polishing experiments are done by using self-made film polishing machine with high speed and cooling inside. Polishing mechanism and polishing technology of what polishing film polishes hard and brittle materials will be studied by changing polishing speed and diamond grain size and so on. The experimental study of wear shape of gringding grain, desquamation process of grain and surface quality of workpiece will be done in this paper so that the reasonable technology of polishing hard and brittle materials with high productivity is obtained. It enrich and perfect the ultra-precision machining theory. A new method of ultra-precision lapping and polishing of hard and brittle materials is provided.
Effect of Nozzle Type and Abrasive on Machinablity in Micro Abrasive Air Jet Machining of Glass
Authors: Fan Jing Ming , Wang Cheng Yong , Wang Jun , Luo Guo Sheng
Published: March 2009

Micro abrasive jet machining (MAJM) is a high effective economical technology for three
dimensional micro structure fabrications of brittle materials. It is widely used in the fabrication of
semiconductors, electronic devices, micro electro-mechanical systems (MEMS), optical-electronic
and optical devices, and medical instruments. In this paper, based on the experimental study of
MAJM for glass, the influences of the nozzle type/size and abrasive type on the material erosion rate
and structure profile are analyzed. The results show that the rectangular nozzle can yield a more
accurate and efficient machining performance due to reduced flux effect. By contrast, with round
nozzle all the cross section profiles of the machined patterns show rounded V-type shape. The
rectangular nozzle is able to produce geometry with flat shape. The machining area is almost
independent of the abrasive hardness, and the erosion rate increases with the increase in the hardness
of the abrasive grits. The nozzle geometry is of great importance for machining accuracy and the
efficiency.
Simulation of the Gas-Liquid-Solid Three-Phase Flow Velocity Field Outside the Abrasive Water Jet(AWJ) Rectangle Nozzle and Ellipse Nozzle
Authors: Hou Rong Guo , Huang Chuan Zhen , Li Li , Niu Zong Wei , Li Zhi Yong
Published: March 2009

Simulation of the flow field of the gas-liquid-solid three-phase flow outside the abrasive
water jet rectangle nozzle and ellipse nozzle is studied by the computed fluid dynamic
software-fluent, and the velocity field of the three-phase flow is obtained. The simulation result
expresses that the flow is expanded when it is out of the nozzle; the velocity of the flow is the
highest at the axis, which comes down by its side, the velocity of the flow is high at the beginning
then it is decreased because the flow is resisted by the air; the shape of the jet at the start is closed to
the geometry of the nozzle, then it is rounded in the external area; the velocity field outside the
ellipse nozzle is distributed evenly around the center. By plotting the velocity field of the rectangle
nozzle and the ellipse nozzle in the Y-Z section, it is expressed that the changing range of velocity is
enlarged with the increasing of distance offset the nozzle.
3D Fractal Analysis of Ultra Precision Grinding Influencing on the Surface Topography of Brittle Material
Authors: Chen Ming Jun , Pang Qi Long , Wang Jing He , Cheng Kai
Published: March 2009

3Dfractal dimension and 2D profile fractal dimension distribution of the surfaces made by brittle or ductile grinding are calculated. From the calculated results of 3D fractal dimension, it can be found that the microtopograhpy of ductile ground surface is more exquisite than brittle ground surface and 3D fractal dimension Ds has inverse relation with the roughness parameter Rq. Through the analysis of 2D profile fractal dimension distribution in different ground surfaces, it is revealed that the topography of ground surface is changed with grinding parameters such as ground surfaces may have weakly or strongly anisotropic even isotropic features when different grinding parameters are adopted. Using fractal method to analyze the topography of ground surface is helpful to understand the generating mechanism of surface topography.
Structural Parameter Optimal Design of a 3-TPS Parallel Grinding Machine Tool Based on Stiffness
Authors: Zhao Liang , Gong Ya Dong , Cai Guang Qi
Published: March 2009

On the basis of static analysis, the stiffness model of the parallel grinding machine tool is established from the 3-TPS parallel grinding machine tool newly designed by Northeastern University. By analyzing its stiffness matrix, the optimal objective is given which is the average of the twenty condition numbers of stiffness matrix corresponding to the twenty positions in the margin areas of the workspace. With MATLAB software, the effects are simulated which the structural parameters of the parallel grinding machine tool have on their stiffness, their change laws are gained, and then the stiffness design of the parallel grinding machine tool are conducted based on these laws.
Effect of Acid Treated Hydroxyapatite on Osteoblast Maturation
Authors: Takemura Taro , Ikoma Toshiyuki , Hanagata Nobutaka
Published: March 2009

Surfaces of sintered hydroxyapatite (HAp) were treated with four kinds of acids,
hydrochloric acid (HCl), nitric acid (HNO3), sulfuric acid (H2SO4) and hydrogen peroxide (H2O2). On
these acid-treated HAp surfaces, osteoblast-like MC3T3-E1 cells were cultured for 20 days. The
matrix mineralization was observed in HCl-treated HAp and HNO3-treated HAp, but not in
non-treated HAp, H2SO4-treated HAp and H2O2-treated HAp. Gene expressions of Bglap2 encoding
osteocalcin and Akp2 encoding alkaline phosphatase were higher in HCl-treated HAp and
HNO3-treated HAp than those in the others. These results indicate that not only hydrochloric acid but
also nitric acid improves performance of HAp to mature osteoblast.
Fully Interconnected Globular Porous Biphasic Calcium Phosphate Ceramic Scaffold Facilitates Osteogenic Repair
Authors: Lim J.H. , Park J.H. , Park Eui Kyun , Kim Hae Jung , Park Il Kyu , Shin H.Y. , Shin Hong In
Published: March 2009

An appropriate scaffold, which provides structural support for transplanted cells and acts as a vehicle for the delivery of biologically active molecules, is critical for tissue engineering. We developed a fully interconnected globular porous biphasic calcium phosphate ceramic scaffold by adopting a foaming method, and evaluated its efficiency as a bone substitute and a scaffold for bone tissue engineering by in vitro and in vivo biocompatible analysis and its osteogenic healing capacity in rat tibial bone defects. They have spherical pores averaging 400um in diameter and interconnecting interpores averaging 70um in diameter with average 85% porosity. They elicited no cytotoxicity and noxious effect on cellular proliferation and osteoblastic differentiation during the cell-scaffold construct formation. Also the bone defects grafted with fully interconnected globular porous biphasic calcium phosphate ceramic blocks revealed excellent bone healing within 3 weeks. These findings suggest that the fully interconnected porous biphasic calcium phosphate scaffold formed by the foaming method can be a promising bone substitute and a scaffold for bone tissue engineering.
Ceramic Total Knee Prosthesis with Smooth Surface Keeps High Wear Resistance in Long Clinical Use
Authors: Kim Sok Chol , Oonishi Hironobu , Oonishi Jr. Hiroyuki , Kyomoto Masayuki , Iwamoto Mikio , Ueno Masaru , Ohashi Hirotsugu
Published: March 2009

In the late 1970s, based on good clinical results in total hip prostheses, the use of a
combination of alumina ceramics and ultra-high molecular weight polyethylene (UHMWPE) was
begun for total knee prostheses (TKPs) in order to reduce UHMWPE wear. In this study, to
examine the in vivo efficacy of the alumina ceramic bearing surfaces of TKPs, we compared
retrieved alumina ceramic TKPs with cobalt-chrome (Co-Cr) alloy TKPs by surface observations
and linear wear measurements. In scanning electron microscopic observations, many scratches due
to clinical use were observed only on the retrieved Co-Cr alloy femoral components. The damage
in the form of scratches on the articulating surface was linear and was produced by rubbing against
the Co-Cr alloy surface. The linear wear rate of the retrieved Co-Cr alloy TKPs was 0.027–0.358
mm/year. In contrast, the wear of the retrieved alumina ceramic TKPs was stably low and linear;
the linear wear rate was estimated to be 0.026 mm/year. The lower wear rate and milder nature of
wear observed in the TKPs with the combination of UHMWPE inserts and alumina ceramic femoral
components suggest the possibility of the retention of high performance even during prolonged
clinical use.
Synthesis and Stability of Potassium/Carbonate Co-Substituted Hydroxyapatites
Authors: Whyte J. , Hadden D.J. , Gibson Iain R. , Skakle J.M.S.
Published: March 2009

A systematic study of the stability of potassium/carbonate co-substituted hydroxyapatite
has been carried out, with samples synthesized by aqueous precipitation according to the chargebalanced
mechanism:
Ca10-xKx(PO4)6-x(CO3)x(OH)2
Samples up to x=1.0 were prepared and their stability determined by heating at a range of
temperatures in both air and CO2 environments. Results showed that whilst samples up to x=1.0
can be prepared phase-pure, the stability of these materials is strongly dependent on sintering
temperature with the full range of compositions only being stable at 600°C in CO2. The c unit cell
parameter increases linearly with x, and, for a fixed composition, decreases linearly with
temperature indicating loss of carbonate from the A-site. FTIR showed that samples contained
carbonate at both A- and B-sites, and that carbonate content increased with x.
Rough Bioglass Films Prepared by Magnetron Sputtering
Authors: Slav A , Ianculescu A. , Morosanu Constantin , Saranti A. , Koutselas I. , Agathopoulos Simeon , Karakassides M.A.
Published: March 2009

Bioglass films were prepared by reactive magnetron sputtering from a 45S5 target and than annealed in air up to 550 oC in order to relax the mechanical stresses. The mixtures (0, 7 and 15%) of oxygen and argon were used in order to modify the films stoichiometry. Morphological and compositional studies were performed by SEM coupled with an EDAX system. FTIR and micro Raman measurements were performed in order to investigate the molecular vibrations of the BG structure. A modified composition respect to the target one was found for all the films, with lower silicon dioxide concentrations. The films displayed rough surfaces with spherical particles of 10-20 μm diameter embedded in the surfaces. The Raman results evidenced important carbonate lines besides the silica-phosphate bands.
Growth Behavior of Rat Bone Marrow Cells on RF Magnetron Sputtered Bioglass- and Calcium Phosphate Coatings
Authors: Wolke Joop G.C. , van den Beucken Jeroen J.J.P. , Jansen John A.
Published: March 2009

The RF magnetron sputter technique was used to deposit Bioglass (BG) and
hydroxyapatite (HA) coatings onto titanium substrates. The aim of this study was evaluated
the growth behavior of rat bone marrow cells of various deposited coatings.
The EDS measurements demonstrated that the composition BG coating was changed during
magnetron sputtering. The rat bone marrow derived osteoblast-like cells showed improved
osteogenic response on crystalline magnetron sputtered HA coatings compared BG coatings.
Scanning electron microscopical examination showed an extensive mineralization after 16
days of culture, while on the surface of the BG coating only a multilayer without
mineralization could be observed.
Sintering Behavior of 45S5 Bioglass®
Authors: Lefebvre Leila , Gremillard Laurent , Chevalier Jérôme , Bernache-Assollant Didier
Published: March 2009

In this study, we report on the effect of Bioglass® structural transformations on its sintering behaviour. In a previous paper, we showed that while heating up to 1000°C, five successive transformations occur: glassy transition, phase separation, two crystallization processes and a second glassy transition. The sintering of the material exhibits two main shrinkage stages associated to the two glassy transitions at 550°C and 850°C. At 580°C, the glass-in-glass phase separation induces a decrease of the sintering rate immediately followed by the crystallisation of the major phase Na2CaSi2O6 between 600 and 700°C, from the surface to the bulk of the particles. A completed inhibition of sintering takes place followed by a minor shrinkage due to volume crystallization. A plateau is observed until the second glassy transition.
Apatite Foam Fabrication Based on Hydrothermal Reaction of α-Tricalcium Phosphate Foam
Authors: Kunio Ishikawa , Karashima Satoshi , Takeuchi Akari , Matsuya Shigeki
Published: March 2009

Apatite foam (AP foam) is an ideal material for bone substitutes and scaffolds in bone
tissue regeneration. This is because its highly porous interconnected pores provide the space for cell
growth and tissue penetration, and that its composition induces excellent tissue response and good
osteoconductivity. In the present study, the feasibility of apatite foam fabrication was evaluated based
on so-called dissolution-reprecipitation reaction of α-tricalcium phosphate (α-TCP) foam granules.
When α-TCP foam granules were placed in water at 37°C for 24h, no reaction was observed.
However, α-TCP foam set to form AP foam when treated hydrothermally at 200°C. The network of
fully interconnected pores was retained, and porosity was as high as 82%. Pore size ranged from 50 to
300 0m with average pore size at 160 0m. Compressive strength was 207 kPa. Although no setting
reaction was observed at 37°C, setting reaction caused by hydrothermal treatment of α-TCP foam
granules at 200°C allows AP foam of any shape to be fabricated. Therefore, this method was
suggested to be useful for the fabrication of bone substitutes and the scaffold in bone tissue
regeneration.
A Comparison of the Efficacy of Hydoxyapatite Based Cements and Gels as Drug Delivery Matrices
Authors: Jiang Peih Jeng , Patel Sarika , Gbureck Uwe , Grover Liam M.
Published: March 2009

There is a current need for the localized delivery of antibiotics in order to treat implant based infections. In this study, the efficacy of hydroxyapatite (HA) gels, HA cements, and silica gels in the delivery of vancomycin have been investigated and compared. Vancomycin release was monitored at set time points using a UV/VIS spectrophotometer (288 nm). The activity of the vancomycin released from the cements and gels was assessed using an agar diffusion test with Staphylococcus aureus. Vancomycin was released rapidly from both HA matrices, and the silica gel in the first day of the experiment, but the release rate was slowed considerably after 3 days for the HA gels. Following ten days of aging, 70% of the vancomycin remained in the HA gel matrix and the quantity released from the gel was shown to retain its effectiveness against Staphylococcus aureus.
In Vitro Biomechanical Testing of Two Injectable Materials for Vertebroplasty in Different Synthetic Bones
Authors: Lööf Jesper , Faris Adam , Hermansson Leif , Engqvist Hakan
Published: March 2009

Two different injectable materials, intended for use in vertebroplasty (VP) treatments of fractured vertebras, were tested in an in vitro bone model. The materials tested were an experimental bioceramic material based on calcium aluminate manufactured by Doxa AB, and Vertebroplastic, a PMMA based material manufactured by DePuy Acromed. The model was earlier developed by others and has been found valid for testing of materials intended for PVP. The model offers alternative data to traditional compressive and diametral tensile testing by adding the infiltration of material into synthetic cancellous bone. Five different synthetic bones with different porosity and pore structure were tested. The results show that for the PMMA the infiltration pattern of the different bones tested seems to have no influence. The material deforms plastically and displays about the same strength in all bones tested. For the bioceramic, linear elastic, material however there is a difference. In the more porous bones, where the material infiltrate the pores and creates a test body with a large amount of crack initiation points, the material displays lower strength compared to that of the more solid bones.
Sol-Gel Synthesis and In Vitro Cell Compatibility Analysis of Silicate-Containing Biodegradable Hybrid Gels
Authors: Tsuru Kanji , Robertson Z. , Annaz B. , Gibson Iain R. , Best Serena , Shirosaki Yuki , Hayakawa Satoshi , Osaka Akiyoshi
Published: March 2009

Novel hybrid gels in the system gelatin-GPTMS-TEOS were prepared via a sol-gel route,
and their ability to release Si(IV) was examined using MG63 osteoblast-like cell culture. The amount
of Si released and the release rate were controllable by changing the mixing ratio of GPTMS and
TEOS. In addition, the hybrids had biocompatible surfaces. It is expected that the hybrids will be
utilized for the investigation of the effect of Si on cell differentiation and tissue regeneration.
A Novel Approach of Homogenous Inorganic/Organic Composite through In Situ Precipitation in Gelatine/Poly(Acrylic Acid) Gel
Authors: Cai Xu An , Tong Hua , Zhao Yu , Shen Xin Yu , Hu Ji Ming
Published: March 2009

A new in situ precipitation technique was developed to promote high-affinity nucleation and growth of calcium phosphate in the polymer hydrogel. Gelatine/poly(acrylic acid)/hydroxyapatite (HA) composite has been prepared using template-driven reaction. Nano-sized hydroxyapatite particles were distributed within organic template homogenously, furthermore, inorganic particles were fine and uniform. During the composite process, 3D network of organic matrices and homogenous distributed nucleation sites played an important role in the superfine interaction of HA and hydrogel. This method provides an efficient approach toward inorganic/organic nanocomposites with high-uniformity decentralization for biomimetic replant applications. This paper discussed the mechanism of the reaction, and the concept of in situ precipitation in gel was brought forward.
Preparation of Bioactive Poly(Lactic-Co-Glycolic)Acid and Silica Gel Fibers Mixed Non-Woven Fabric
Authors: Seol Yang Jo , Kim In Ae , Lee Yong Keun , Lim Bum Soon , Rhee Sang Hoon
Published: March 2009

Poly(lactic-co-glycolic)acid and silica gel fibers mixed non-woven fabric was made by
electro-spinning method for the potential application as a bone grafting material. The silica gel, the
source material for electro-spinning, was prepared by the hydrolysis of tetraethyl orthosilicate in the
presence of calcium salt, water, hydrochloric acid and ethanol. Poly(lactic-co-glycolic)acid solution
was prepared by dissolving it in the hexafluoroisopropanol. Then, they were transferred to two
separate syringes which were connected to the high voltage supply generating a high electric field
between the spinneret and the ground collecting drum. The silica gel containing calcium and
poly(lactic-co-glycolic)acid solution were spun together under the electric field of 2 ㎸/㎝. The
FE-SEM observations showed that the silica gel and poly(lactic-co-glycolic)acid fibers were mixed
together completely and its handling property was much improved compared to that of the non-woven
silica gel fabric. After soaking in the SBF for 1 week, low crystalline apatite crystals were also
observed to occur on the silica fiber surfaces first and then they were also observed to occur on the
poly(lactic-co-glycolic)acid fiber surfaces. From the results, it can be concluded that the
poly(lactic-co-glycolic)acid and silica gel fibers mixed non-woven fabric made by electro-spinning
method has a bioactivity. It means it has a potential to be used as a bone grafting material because of
its apatite-forming ability, high surface area to volume ratio and high porosity.
Synthesis of Si-Containing Tricalcium Phosphate and its Sintering Behavior
Authors: Kamitakahara Masanobu , Kurauchi Takashi , Tanihara Masao , Ioku Koji , Ohtsuki Chikara
Published: March 2009

Si-containing tricalcium phosphate (TCP) ceramics are expected to be useful
biodegradable bone substitutes that enhance bone regeneration because TCP is a biodegradable
ceramic and Si is the trace element that enhances bone formation. We successfully synthesized the
Si-containing TCP with different Si contents through a wet process. The Si addition lowered the
temperature of phase transition from β-TCP to α-TCP. After the sintering the compacts of
Si-containing TCP powders at 1400 oC, the sintered ceramics showed higher density than those of
Si-free TCP. The Si addition was effective to promote the sintering of TCP.
Histomorphometric Evaluation of Bone Response to Different Titanium Implant Surfaces
Authors: Le Guenhennec Laurent , Goyenvalle Eric , Lopez-Heredia Marco A. , Weiss Pierre , Amouriq Yves , Layrolle Pierre
Published: March 2009

Titanium dental implants presenting different blasted surfaces and an OCP coated
surfaces have been implanted in the femoral epiphysis of rabbits. A comparable osseointegration has
been observed for the titanium implants blasted either with alumina or biphasic calcium phosphates
particles whatever the delay of implantation (2 or 8 weeks). A higher bone to implant contact has
been observed for the SLA and OCP coated implants as compared to the grit-blasted groups.
Phase Stability and Fracture Toughness of Zirconia Toughened Alumina for Joint Replacement
Authors: Ikeda Junji , Mabuchi Megumi , Nakanishi Takefumi , Miyaji Fumiaki , Ueno Masaru , Pezzotti Giuseppe
Published: March 2009

As for zirconia toughened alumina (ZTA) with various ratios of alumina/zirconia, crystal and micro structures, fracture toughness and phase stability were evaluated by X-ray diffraction, Raman spectroscopy, and aging test in hydrothermal environment. The grain size and monoclinic fraction of zirconia phase and residual stress in alumina matrix changed as a function of zirconia content. The ZTA showed higher fracture toughness than conventional alumina. The fracture toughness of ZTA was highest at which the content of tetragonal zirconia was maximum. The monoclinic fraction of ZTA did not increase even after aging test at 121°C for 150 hr. This study indicates that the optimization of tetragonal zirconia content is essential for achieving higher fracture toughness of ZTA. The ZTA with phase stability as well as with fracture toughness is expected as bearing materials which could extend lifetime of artificial joints in clinical use.
Effect of Different Stabilizer Addition on Preparation and Hydrothermal Stability of ZrO2-TiN Composites with Varying TiN Content
Authors: Arin Melis , Vleugels Jef , Vanmeensel Kim , Goller Gultekin
Published: March 2009

Fully dense ZrO2-TiN composites containing 1.75-2 mol %Y2O3, 1 mol% Y2O3 and 1 mol% Nd2O3 stabilizers, small amounts of Al2O3, and electrical conductive TiN particles (40-70 vol%) have been produced by hot pressing and spark plasma sintering at 1550°C. Although the intrinsic hardness of TiN (1400 kg/mm²) is higher than that of t-ZrO2 (1200 kg/mm²), the decreasing hardness trend can be attributed to the larger TiN grain size with the higher TiN content. Since TiN is more brittle, the fracture toughness decreases with increasing TiN content. Transformation toughening has been attributed as the main toughening mechanism as a result of fracture toughness decreasing with the transformability. Spark Plasma sintering temperature was too high for mechanical properties and hydrothermal stability of the mixed stabilized composites. The transformability decreases so hydrothermal stability increases linearly with increasing TiN content as a result of smaller volume fraction of t-ZrO2 grains becoming susceptible to hydrothermal transformation due to the shielding effect of the present TiN grains.
Modular Ceramic Bearings on a CFRP Total Hip Replacement Femoral Stem
Authors: Dickinson Alex , Browne M. , Taylor Andy
Published: March 2009

A modular ceramic femoral head was selected for use as the bearing on a novel carbon
fibre reinforced plastic (CFRP) total hip replacement femoral stem. Mechanical testing was required
to validate this novel combination of materials for load bearing implant application. The Ceramic
Head-CFRP Stem Taper interface was tested under axial fatigue loads according to BS/ISO 7206-5,
followed by static loading to failure. The assembly survived the fatigue loads and exceeded the
required FDA post-fatigue strength by 50%. In parallel, the test was simulated in a Finite Element
Analysis study, resulting in recommendations for the adhesive bonding technique used to attach the
modular head to the CFRP stem to further improve its strength.
Development of Modelling Methods for Materials to be Used as Bone Substitutes
Authors: Gabbrielli R. , Turner I.G. , Bowen Chris R.
Published: March 2009

The demand in the medical industry for load bearing materials is ever increasing. The
techniques currently used for the manufacture of such materials are not optimized in terms of
porosity and mechanical strength. This study adopts a microstructural shape design approach to the
production of open porous materials, which utilizes spatial periodicity as a simple way to generate
the models. A set of triply periodic surfaces expressed via trigonometric functions in the implicit
form are presented. A geometric description of the topology of the microstructure is necessary when
macroscopic properties such as mechanical strength, stiffness and isotropy are required to be
optimised for a given value of volume fraction. A distinction between the families of structures
produced is made on the basis of topology. The models generated have been used successfully to
manufacture both a range of structures with different volume fractions of pores and samples of
functional gradient material using rapid prototyping.
High Accuracy Confocal Full-Field 3-D Surface Profilometry for Micro Lenses Using a Digital Fringe Projection Strategy
Authors: Chen Liang Chia , Chang Yi Wei
Published: March 2009

A high-accuracy full field 3-D surface profilometer using digital structured fringe
projection is presented in the article. In the proposed method, a depth-focus response curve can be
established by performing a confocal scanning along the optical axis of the measurement system
when a digital fringe is controlled and projected by a digital micromirror device (DMD). To avoid
specular light diffusive problems, the developed method projects spatially encoded digital fringe
patterns with modulated light intensity onto a shinny lens surface, in order to achieve full field and
high accuracy measurement. Some of spherical microlenses have been measured to attest the
feasibility of the developed approach. The depth measurement resolution can reach up to 0.1μm and
the averaged measurement error was verified to be a submicro scale.
Intelligent Vision Based Technique Using ANN for Surface Finish Assessment of Machined Components
Authors: Narayanan M.Rajaram , Gowri S.
Published: March 2009

In this work, an FPGA hardware based image processing algorithm for preprocessing the
images and enhance the image quality has been developed. The captured images were processed
using a FPGA chip to remove the noise and then using a neural network, the surface roughness of
machined parts produced by the grinding process was estimated. To ensure the effectiveness of this
approach the roughness values quantified using these image vision techniques were then compared
with widely accepted standard mechanical stylus instrument values. Quantification of digital images
for surface roughness was performed by extracting key image features using Fourier transform and
the standard deviation of gray level intensity values. A VLSI chip belonging to the Xilinx family
Spartan-IIE FPGA board was used for the hardware based filter implementation. The coding was
done using the popular VHDL language with the algorithms developed so as to exploit the implicit
parallel processing capability of the chip. Thus, in this work an exhaustive analysis was done with
comparison studies wherever required to make sure that the present approach of estimating surface
finish based on the computer vision processing of image is more accurate and could be
implemented in real time on a chip.
The Design of an Integrated Pick-Up Head for High-Density Digital Versatile Disk, Digital Versatile Disk and Compact Disk
Authors: Sun Wen Shing , Sun Ching Cherng
Published: March 2009

A novel design of triple-wavelength design for a compact optical pickup head is
presented here. We propose the use of two rhomboid beam-splitter prisms for HD-DVD, DVD and
CD devices to align signals with three different wavelengths on the same optical axis. The light is
collimated by a collimating lens. The parallel beams are incident on the wavelength selector. The
wavelength selector separates the wavelengths with different numerical apertures. The different
wavelength signals are focused on the disc by an objective lens.
Precision Machining of Silicon Carbide with Diamond Micro Tool Array (DMTA)
Authors: Zhao Qing Liang , Yu Guang , Sun Tao , Dong Shen
Published: March 2009

An advanced conditioning technique was developed to precisely and effectively condition the nickel electroplated mono-layer coarse-grained diamond grinding wheel of 46m and 91m grain size with an aim to fabricate Diamond Micro Tool Arrays (DMTA), to meet the high demands of form accuracy, surface quality and low subsurface damage in ductile machining of silicon carbide (SiC). The precision machining experiments on SiC were carried out on a precision grinder to determine the applicability of these fabricated diamond micro tool array (DMTA). The experimental result indicates that the newly developed DMTA is applicable and feasible to realize ductile machining on SiC with high efficiency and low diamond tool wear rate, which shows a good prospect to apply this new concept diamond tool type in precision machining of SiC, as well as the other brittle and hard-to-machine materials.
Automatic Optical Inspection on TFT-LCD Mura Defects Using Background Image Reconstruction
Authors: Chen Liang Chia , Kuo Chia Cheng , Yen Ping Ang
Published: March 2009

A mura defect detection algorithm for thin-film transistor liquid crystal display (TFTLCD)
is developed for automatic detection of mura defects using Discrete Cosine Transform (DCT)
principle for background image reconstruction. Detecting blob-mura defects in a LCD panel can be
difficult due to non-uniform brightness background and slightly different brightness levels between
the defect region and the background. To resolve this issue, a DCT-based background
reconstruction algorithm was developed to establish the background image. The background of the
inspected images can be first extracted and reconstructed by using the DCT principle and an image
filtering strategy. Mura defects can then be detected by the developed segmented strategy. Actual
performance of the developed method was evaluated on industrial LCD panels containing natural
mura defects.
Study of Mold Design on SD Card with 3D Mold-Flow Analysis
Authors: Huang Shih Miao , Jou Rong Yuan , Lin Jui Chang , Lee King Sun
Published: March 2009

This research applies 3D mesh mold-flow analysis to analyze the SD (Secure Digital) card. It aims at temperature of the mold and plastic. The proper mold filling temperature is found by simulation analysis to improve the short shot situation, and seeks the cause of warping via various processed conditions. SD memory card clip has a big variation in thickness. Due to the bigger flow resistance the plastic is difficult to reach thinner portion, even hot plastic is also difficult to supply. The temperature of plastic goes down as a result of the cold mold cavity. Thus, the plastic does not reach certain portions before solidifying. The cooling system of injection machine was controlled by constant temperature oil cooling. This study explored the optimum injection condition by utilizing experiment to control the temperature of the plastic, the temperature of mold, the packing pressure process and so on. It is valuable to companies which utilize injection mold applications.
Design of Protective Coatings for Glass Lens Molding
Authors: Ma Kung Jeng , Chien H.H. , Chuan W.H. , Chao Choung Lii , Hwang K.C.
Published: March 2009

The glass molding process is considered to have a great potential for the mass production
of aspherical glass lenses with high precision and low cost. However, glass molding has a serious
problem of mold sticking with glass which needs to be resolved. This research investigates the
interface reaction between glass and mold by high temperature wetting experiment, which provides
the reference for the designing anti-stick coatings. The SUMITA K-PSK200 optical glass gobs with
low Tg were used in this study. The influence of operation temperature, ambient gas, substrate
materials, and thin film composition on wettability of glass at high temperature were studied. The
results show that the higher the temperature, the smaller the wetting angle between glass gob and
substrate could be observed. This indicates that severe interface chemical reaction occured and
resulted in the loss of transparency in glass appearance. The wetting experiment in nitrogen ambient
improved the sticking situation. The combination of chemically stable substrates and coatings, such
as Sapphire (substrate) / GaN (film) and Glass (substrate) / Al2O3 (film) can achieve the best antistick
propose. The precious metal films, such as Pt, Ir, coated on the ceramic substrates can
effectively reduce the interface reaction between the glass and substrates.
Pulsed LED Illumination for High Speed Imaging
Authors: Aikio Mika , Lindström Hannu , Juntunen Eveliina , Kataja Kari , Keränen Heimo
Published: March 2009

High speed imaging with decent image quality is difficult because the available exposure times are very short, which leads to the usage of a large aperture. Unfortunately, large aperture also decreases the depth resolution of the system, which reduces the quality of the image. Thus the source of illumination has to be able to output a high amount of energy in a very short time so that the aperture requirement can be relaxed. There are only a few Xenon flash lamps that fulfill the requirement of sub-microsecond pulses, so the natural choice would be to use lasers. However, when the target surface is rough, high degree of coherence causes black and white interference patterns known as speckle. The sensor might register irradiance values from zero to saturated state. Needless to say, this reduces drastically the quality of the image. There is variety of techniques for speckle removal, ranging from chaotic laser states to digital signal processing [1-5]. In this paper we discuss an alternative, namely LEDs, for this kind of illumination. The authors have performed some experiments and theoretical modeling, and successfully demonstrated an illumination system based on LEDs that can output enough energy to enable imaging with pulse lengths of 100 ns.
Study of Etch Rate and Surface Roughness in Chemical Etching of Stainless Steel
Authors: Çakır Orhan
Published: March 2009

In this study, stainless steel material (X5CrNi1810) was micromachined by chemical etching method. Ferric chloride was selected as etchant which is the most widely used etchant for iron-based materials. Four different etchant concentrations (32 °Bé, 36 °Bé, 40 °Bé and 44 °Bé) were used at various etching temperature. Moreover, the influence of the addition of hydrochloric acid to main etchant on etching performance was examined. The aim of this study was to investigate the depth of etch and surface roughness affected by etchant concentration, hydrochloric acid addition and etching temperature. It was observed that etching temperature for any etchant concentration is important factor in case of depth of etch and surface roughness. It was also noticed that the addition of hydrochloric acid to main etchant increased depth of etch value at any etching temperature. The optimum etching parameters were obtained for the chemical etching of stainless steel.
A Finite Element Analysis for the Initial Blank’s Shape Design of Sheet Metal in Deep Drawing Process
Authors: Yang Tung Sheng , Hsu Yuan Chuan , Lin Heng Sheng , Chang Sheng Yi
Published: March 2009

In the deep drawing of cups, the earing defect is caused primarily by planar anisotropy in
the sheet. In order to obtain the optimal products in deep drawing process, blank shape is a very
important formability factor. In this study, the finite element method was used to investigate the cup
height and forming force of the cylindrical cup drawing process. A finite element analysis was also
utilized to acquire the designed profile of the drawn products, a reverse forming method for
obtaining the initial blank’s shape according to the forward cylindrical cup drawing simulation is
proposed. The design of initial blank’s shape is also confirmed to obtain the designed profile of
drawn cups. The influences of the blank’s shape on the height of product, the forming force, the
effective stress and the effective strain were also examined.
A New Low Friction Die Design for Equal Channel Angular Extrusion
Authors: Canta Traian , Frunză Dan , Szilagyi Eniko , Lungu Magdalena
Published: March 2009

The paper presents the experimental results on an aluminum alloy and a silver alloy
processed by equal channel angular extrusion in order to refine the grains. Two type of extrusion
dies have been used for experimental works: one with fixed walls and the other one with movable
walls in order to reduce the friction during extrusion process. The new concept of the die consists in
simultaneously pressing of two samples in one entering channel with two opposite exit channels.
The channel geometry, friction contact, strain rate, extrusion load and micro structure aspects are
presented.
Online-Joining of C/SiC-C/SiC via Precursor Infiltration and Pyrolysis Process
Authors: Lu Yang Wei , Zhang Yu Di , Hu Hai Feng , Zhang Chang Rui
Published: March 2009

A novel, online-joining of C/SiC-C/SiC method, precursor infiltration and pyrolysis, was used
to obtain high temperature stable joining SiC composition, while joining process was highly consistent
with C/SiC preparation process. The compositions of joining ingredients and process parameters were
investigated to determine the maximum joining strength of C/SiC-C/SiC at room and high temperatures.
The optimum weight ratio of (polycarbosilane/divinyl benzene)/SiC powder is 3/1, and ramping rate of
pyrolysis is 2°C/min, and cycles of infiltration and pyrolysis is 6. The flexural strengths of joining
components remained stable up to 1200°C (50.8MPa), but decreased to 30.5MPa at 1500°C, while the
tensile strengths remained rather stable (20.5MPa) up to 1500°C, and decreased to 8.4MPa at 1800°C.
Thermal Conductivities of β-Si3N4 and BN-Filled Epoxy Molding Compounds (EMC)
Authors: Yuan Zhu , Chen Ke Xin
Published: March 2009

New electric molding composites were fabricated with hybridizing epoxy and several fillers. The examined fillers were β-Si3N4, BN and fused silica or their combinations. The thermal conductivity of β-Si3N4 filler was compared with BN as filler for advanced epoxy molding compounds. The influence of pure resin matrix and mixture matrix on the thermal conductivity of EMC was discussed. The results were explained with Maxwell equation.