bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Roller Working on Fatigue Strength of Structural Metals
Authors: Zhou Cong Ling , Nishida Shinichi , Hattori Nobusuke
Published: March 2009

Three kinds of materials, pure aluminum (Al1050), carbon steel (S25C) and eutectoid steel (NHH) with V-notch are used in this study to compare the effect of roller working on the fatigue properties among the test materials. As the result, all of the fatigue strengths are improved after roller working and the optimum deformation values exist for every test materials. Fiberized microstructure at the notch bottom, work hardening and compressive residual stress caused by roller working are considered as the main reasons for the fatigue strength improvement. The highest fatigue strength improvement of Al1050, S25C and NHH was 30%, 118% and 155%, respectively. The optimum fatigue improvement of NHH is the highest and it is much higher than that of Al1050, and the optimum deformation value of Al1050 is much lower than that of the other materials. Moreover, the roller working effect is much remarkable for the materials with better hardenability.
Nonlinear Dynamic Response of Piezoelectric Plates Considering Damage Effects
Authors: Fu Yi Ming , Wang Xian Qiao
Published: March 2009

Based on the Talreja’s tensor valued internal state variables damage model and the
Helmhotlz free energy of piezoelectric material, the constitutive relations of the piezoelectric plates
with damage are derived. Then, the nonlinear dynamic equations of the piezoelectric plates
considering damage are established. By using the finite difference method and the Newmark
scheme, these equations are solved and the effects of damage and electric loads on the nonlinear
dynamic response of piezoelectric plates are discussed.
Crack Growth Behavior of Al Alloy under Ultrasonic Fatigue
Authors: Kawagoishi Norio , Chen Q. , Oki M. , Wang Qing Yuan
Published: March 2009

In order to investigate the effect of frequency on the crack growth behavior, ultrasonic fatigue tests were carried out for an extruded age-hardened Al alloy, 7075-T6, and the results were compared with those in rotating bending fatigue. Fatigue strength in ultrasonic was higher than that in rotating bending. This was mainly caused by the retardation of crack initiation. Growth direction of a crack changed from a tensile mode to a shear one in ultrasonic fatigue, though fracture occurred by the growth of a tensile mode in rotating bending. The growth direction of a shear mode crack was inclined about 55 degrees to the tensile axis. The relation between an applied stress σa and a crack depth at transition of growth direction T was expressed by a nT=C, where C and n are constants. These results were discussed from the points of view of the time dependent environmental effect and the texture of material.
Numerical Simulation of 3-D Fracture Behaviors on the FRP-Strengthened Concrete Structures
Authors: Zhang Juan Xia , Tang Chun An , Hui Xing Jie , Zhu Wan Cheng , Liang Zheng Zhao , Zhang Yong Bin , Guo Xian Zhang
Published: March 2009

A numerical code RFPA3D (Realistic Failure Process Analysis) is used to simulate the crack initiation and propagation in FRP-strengthened concrete beam under external loading. In our model, the FRP-strengthened concrete is assumed to be a three-phase composite composed of concrete, FRP, and interface between them. The displacement-controlled loading scheme is used to simulate the complete failure process of FRP-strengthened concrete the numerical simulation of failure process of the specimens. It is found that the main failure mode is the interfacial debonding and the interfacial debonding may propagate either within the adhesive layer or through concrete layer in the vicinity of bond interface. The simulation results agree well with the experiment observations. The width of the FRP sheet is considered an important factor not only to significantly influence the debonding propagation type and crack distribution but also to control the ultimate load-capacity and ultimate strain. This study is focused on the failure process of the FRP-strengthened concrete beam and the effects of the width of FRP sheet on the failure mode and on the structural load-carrying capacity of concrete structures.
Numerical Calculation of Peeling Strength in Anisotropic Conducive Adhesive Bonding
Authors: Zhang Jun , Chen Xu , Wei Xin Li
Published: March 2009

The cohesive zone interface model was used to calculate 90o peel in the ACF bonding samples. The constitutive equation for the interface model was modified by introduction a damage factor χ . The thermal damage factor and humidity damage factor can be derived from the experiment data. The interfacial model with damage factor can change the maximal peel stress and the delamination length. The calculation result of the interfacial model with damage factor agreed well to the experiment of the 90o peeling.
Numerical Simulation for Dynamic Crack Propagation by MLPG
Authors: Liu Ying , Gao Ling Tian
Published: March 2009

In this paper, a new algorithm based on Meshless Local Petrov-Galerking (MLPG) method is presented for analyzing the crack dynamic propagation. A new modified Moving Least Squares approximation is proposed to simplify the treatment of essential boundary conditions. Explicit central difference with lumped mass matrix is adopted for the time integral. Visibility criterion with crack edge node adding technique and the maximum hoop stress criterion are used to describe the crack propagation and forecast the crack propagation direction. Based on this algorithm, three-point bend specimen for impact fracture test is investigated. Comparing the results with those obtained by the laser caustic method and high-speed photographs, the accuracy of the present algorithm is proved.
MMM Fatigue Damage Evaluation and Life Prediction Modeling for Ferromagnetic Materials
Authors: Xing Hai Yan , Xu Min Qiang , Wang Ri Xin , Zhang Jia Zhong
Published: March 2009

The metal magnetic memory (MMM) technology, based on the magneto-elasticity and
magneto-mechanical effect theory, has been applied to remaining fatigue life prediction. The
correlation between fatigue life and MMM parameter has been investigated through rotary bending
fatigue experiments. Steel X45 samples, with artificial cracks of different depth and breadth, are
tested with MMM method. Based on the results of the metallographic examination, the feasibility
of remaining fatigue life prediction is studied. A new remaining fatigue life MMM model of
ferromagnetic material is presented. The proving experiments show the maximum error of
remaining fatigue life is 4.58% between MMM model calculation and the actual life. The
agreement of remaining fatigue life predicting values and testing values is found to be quite good.
Frequency Tuning Characteristics of Multi-Layered Micro-Resonators Using Thermal and Piezoelectric Actuation
Authors: Oh Il Kwon , Kim Dong Hyun
Published: March 2009

Frequency tuning characteristics of the multi-layered micro-resonators have been
extensively investigated by using thermal and piezoelectric actuations. Based on the layerwise
displacement theory and geometric nonlinear formulation, the nonlinear deformation and its attendant
vibration characteristics of un-symmetrically deposited camped-camped micro-beams under
piezoelectric and thermal actuations have been analyzed. The effects of the eccentric piezoelectric
actuation and uniform thermal loading on the large deflection and natural modes were discussed with
respect to geometric nonlinear responses and initial imperfection. Present results show that both
piezoelectric and thermal actuations can effectively tune the resonant frequencies as increasing and
decreasing desired values by the alternative selection of the dominance between in-plane deformation
and out-of-plane deformation.
Dynamics of a Mode III Crack Impacted by Elastic Wave in Half Space with a Removable Rigid Cylindrical Inclusion
Authors: Yang Zai Lin , Liu Dian Kui , Lv Xiao Lang
Published: March 2009

Scattering of SH wave by a crack is studied in elastic half space with a removable rigid
cylindrical inclusion by Green’s function, complex function and moving coordinate method. In half
space, firstly the scattering wave function of removable rigid cylindrical inclusion is constructed;
next a suitable Green’s function is solved for present problem, then using crack-division to make a
crack. Thus the solution of problem can be obtained. Numerical examples are provided and
discussed.
Numerical Evaluation of Ultimate Strengths of Composites Considering Both In-Plane Damage and Delamination
Authors: Peng Wen Jie , Chen Jian Qiao
Published: March 2009

Traditional laminate strength analysis only considers face failure under in-plane loads. In
fact, owing to the mismatch of the mechanical properties of the adjacent layers, a three-dimensional
interlaminar singular stress fields develop in a small boundary region in the vicinity of the free
edges of the laminate under mechanical load, which may lead to interlaminar delamination failure.
Neglecting this interlaminar failure mode, the failure strength of laminate will be overestimated. In
this paper, face failure and interlaminar failure are both considered. So for a lamina, three major
failure modes are considered: matrix failure, fiber breakage and delamination. Finite element
method is used to obtain the stresses in a laminate under mechanical loads. Stress-based criterions
are adopted to predict the failure mode of laminas. When a lamina is failed, the lamina stiffness is
reduced according to the corresponding failure mode, and the stresses of the laminate are
re-analyzed. This procedure is repeatedly performed until the whole laminate fails and thus the
ultimate strength is determined. The predicted ultimate strengths are in good agreement with
experiment results in the open literature.
Developement of Mathematical Model for Detection of Cracks in Tooth Root Using an Adaptive Algorithm
Authors: Ploj Virtič Mateja , Aberšek Boris , Čudina Mirko , Belšak Aleš
Published: March 2009

This paper presents a control and diagnostics model of single stage gear wheels using
acoustic responses. The model is based on various methods and procedures that provide information
about the generator’s condition and, specifically, its service life. Four procedures are combined in
this model: the mathematical module of the gear wheel that translates the complete mechanical
module into mathematical form, the adaptive FIR (Finite Impulse Response) filter that calculates
impulse responses from the non-linear system, the module for calculating any impulse response,
and the FFT (Fast Fourier Transform) frequency analysis used for simulating frequency spectrums.
The result of the simulation is the sound frequency spectrum that allows the analysis of gear wheel
tooth damage and, based on this spectrum, calculation of the remaining service life and/or the
maintenance process.
Modeling the Damage Progression in the Composite Structure Subjected to Static Contact Crush
Authors: Jiang Yun Peng , Guo Wan Lin
Published: March 2009

Based on the classic laminate theory, a progressive damage model has been incorporated
into the composite structure analysis by using a commercial code, ABAQUS, via one of its
user-defined subroutine, UGENS. The developed user subroutine can be applied to simulate fiber
and matrix damage processes in the general composites structures. The responses of flat laminate
subjected to static contact crush have been studied to verify the efficiency of the presented damage
method. The predicted load-displacement relationships, damage distribution were obtained and
compared with the corresponding experiments, and the results were found to be in good agreement.
Dynamic Fracture Behaviors of Polypropylene/Polyamide-6 Blends
Authors: Li Zheng , Wang Jun , Qin Wei Zhong
Published: March 2009

The dynamic fracture properties of polypropylene/nylon-6 (PP/PA6) blends, with different weight fractions and different compatibilizars, are investigated by reflected dynamic caustics experiments. According to the shadow spot patterns around a moving crack tip, which are recorded during the dynamic fracture process, dynamic fracture toughness and crack growth velocity can be estimated to evaluate the fracture properties of polymer blends. Moreover, combined with microscopic observation, the damage mechanism of the polymer blends is discussed.
Numerical Simulation and Analysis on Crack Path Deviation in Brittle Solid
Authors: Ma Tian Hui , Tang Chun An , Xu Tao , Liang Zheng Zhao
Published: March 2009

Ductile tearing of brittle solid with initial crack is studied numerically. This work is
focused on the simulation and analysis of crack path deviation for the respective configuration and the
study of relation between crack length and the fracture resistance, and that the configuration of
fracture surface is also observed. The simulating tool is a novel numerical code, 3D Realistic Failure
Process Analysis code (abbreviated as RFPA3D). The simulating investigation has shown that the
fracture resistance decreases with the increase of the angle between the crack ends and horizontal
direction. Due to heterogeneity of materials distribution, crack path deviation towards the softer zone
or elements is observed. The topography of the non-planar fracture surface has plotted. Concluding
the simulation made in the present study, the problem of crack extension in the brittle solid can be
handled by RFPA3D. Fracture resistance can be predicted and the crack path deviation be simulated,
if the model parameters have been carefully identified and the mesh design is adequate. So this work
is beneficial to choose safe load-spots and predicate the direction of the crack path deviation.
Modeling of Dry Sliding Wear Using a Systematic Approach
Authors: Ashraf M. Azeem , Sobhi-Najafabadi Bijan , Ellis Michael G. , Hsu Hung Yao
Published: March 2009

Virtual life testing is becoming a widely accepted methodology for predicting the life span of products. In this method, reliable models are important to predict different aspects of design performance, one of which is wear. Wear and has been a subject of numerous scientific and empirical investigations. Due to the complex and dynamic nature of the phenomena, there is no general wear model, which can be adopted for all wear problems. A systematic approach to the modelling of dry sliding wear using analytical time domain models is presented in this paper. Given the sliding distance, the model is capable of predicting wear status in transient (running-in) and steady-state operating conditions. The validity of the modelling approach is demonstrated by comparing the predicted results of wear experiments, with that actually measured. For simplicity, the model is based on sliding distance as input variable, while other factors like temperature, load, surface conditions are treated as constant. A simple geometry of sliding polymer-based contacts is used for establishing of wear model.
An Interval Analysis for the Mesco Ductile Fracture
Authors: Liu Chang Hong , Huang Hu
Published: March 2009

With the concepts of the confidence interval, a random parameter can be transformed into
an interval number in the mesco ductile fracture. Hence analyses of the random isolated void model
can be used in the interval analysis method. Based on the macro- and mesco-experimental results of
four steels, 30CrMnSiA, 40CrNiMoA, No.45 and No.20, the probabilistic fracture characteristics of
the four steels are given. Finally the interval isolated void models in the four steels are discussed.
Mechanical Performances and Failure Modes of Direct Diffusion Bonding Joints of 316L Stainless Steel
Authors: An Zi Liang , Tu Shan Tung
Published: March 2009

Direct diffusion bonding of 316L stainless steel was performed at 850-1100°C for 1-3 h
under a pressure of 10MPa in this study. The effect of bonding temperature and holding time on
mechanical performances of the joints was investigated. Tensile tests were conducted to evaluate
strength and elongation of the joints at room temperature and elevated temperature of 550°C. The
microstructure and fracture surfaces of the joints were examined by optical microscope (OM) and
scanning electronic microscope (SEM). The results indicated that the elongation of the joints
increased with the increase of bonding temperature and holding time. However, overlong holding
time had a side effect on the strength of the joint. Moreover, the change of the mechanical properties
was closely related to the variation of the microstructure of the joints. The X-ray diffraction (XRD)
analysis revealed that FeCr and Fe0.64Ni0.36 were formed at the DB6 joint during bonding process. It is
suggested that FeCr should be detrimental to the improvement of high temperature strength of the
joint.
Laser Truing and Dressing of Small Vitrified CBN Grinding Wheel
Authors: Wu Yong Bo , Wang Xu Yue , Tachibana T. , Kato M.
Published: March 2009

This paper aims at the development of an alterative technique for truing and dressing a small vitrified CBN grinding wheel used for the internal finishing of small holes measuring several millimeters in diameter. In conventional truing and dressing, a single-tip diamond dresser or a rotary GC cup wheel dresser is employed. This levels off the improvement in the wheel truing accuracy because the stiffness of the grinding wheel shaft with an open-sided structure is low, and the shaft is thus deformed easily due to the truing force. In the present work, a new truing and dressing technique is proposed in which a Nd:YAG laser beam is employed as the dresser. Experiments were carried out with respect to the effects of the laser beam conditions (amplitude, width and frequency of pulse, and focus offset) and the relative motion between the laser beam and CBN wheel. It was found that the run-out of the CBN wheel was decreased significantly, and the wheel surface condition was improved greatly after laser truing and dressing.
Development of Solid-Type Diamond Rotary Dresser Utilizing CVD Diamond Disc - Application to Low-Speed Dresser -
Authors: Kubo Akihiko , Tamaki Junichi
Published: March 2009

A solid-type diamond rotary dresser consisting of a CVD diamond disc is developed and
applied to the dressing of a vitrified CBN grinding quill for internal grinding. This dresser has a
feature not found in the other discrete-type rotary dressers used thus far, in which it continuously
contacts the grinding wheel and leaves a spiral on the grinding wheel surface. The solid-type
diamond rotary dresser was mounted on a low-speed spindle supported by journal bearings, and its
dressing performance was compared with those of two discrete-type rotary diamond dressers: a
dressing roll on which surface single diamond grains are brazed and a dressing roll made of a
metal-bonded diamond wheel. It is found that the solid-type diamond rotary dresser tends to bring
about rough grinding conditions among the three dressers.
A New Complex Grinding Method for Ceramic Materials Combined with Ultrasonic Vibration and Electrodischarge Machining
Authors: Suzuki Kiyoshi , Uematsu Tetsutaro , Iwai Manabu , Ninomiya Shinichi , Sano Sadao , Nakagawa Takeo
Published: March 2009

A new complex grinding method named Ultrasonic Electrodischarging Grinding Method
(US-ED-G in short) is described. In the US-ED-G, ultrasonic grinding and ED grinding are
simultaneously carried out on an electrically conductive workpiece with a metal bond grinding wheel.
When compared with other complex grinding methods, the US-ED-G is remarkably effective in
reducing grinding force a great deal and maintaining grinding ability of a wheel for a long time in
efficient grinding of extremely hard-to-grind ceramic materials like TiB2. A stock removal rate of
200mm3/min and a grinding ratio of 110 have been attained by selecting appropriate conditions in
US-ED-G of TiB2. A compact and rigid ultrasonic attachment is also described, which was developed
as a removable tool for carrying out US grinding and US-ED-grinding on a machining center or a
grinding center.
Shear Strength of Brazed Joint between Diamond Grains and Steel Matrix Using a Ni-Cr Filler Alloy
Authors: Xu Jiu Hua , Ding Wen Feng , Qian F.
Published: March 2009

The joining strength and corresponding fracture mechanism of the brazing interface
between diamond grains and tool matrix is one of the primary problems in the development and
application of brazed diamond grinding tools. In this study shearing tests were performed for the
brazed joints, meanwhile the fracture mechanism and the joining characteristics were analyzed
deeply. The results indicate that, depending on the metallurgical integration effect through the atom
diffusion between the filler alloy and the metal matrix, and on the strong chemical bond by the
new-formed Cr-C compounds between the filler alloy and diamond grains, hard and reliable joining
is realized at the grain interfaces, which significantly supports the potential advantages of the latest
brazed diamond grinding tools.
Machinability in Precision Cutting of Carbon Tool Steel for Small-Size Parts
Authors: Okuda Koichi , Takeno Y.
Published: March 2009

High accuracy and high efficiency machining of micro parts such as a
contact probe for a current inspection of semiconductor is increasingly demanded. In
this study, we have focused on a micro cutting technology of a carbon tool steel which
is a typical material for a contact probe. In order to put the precision cutting of the
high strength material into practice, it is essential to understand the micro cutting
phenomenon such as the surface texture, the tool wear with small depth of cut and low
cutting speed. Then, the precision cutting experiments of a carbon tool steel (SK105)
by titanium carbide and ultra-fine grained tungsten carbide tools were carried out with
an ultra-precision cutting machine. It was found that the feed rate, the cutting speed
and the edge sharpness of tool significantly influence the surface finish.
Theoretical Analysis and Simulation of the Effect of Vibration Amplitude on Cutting Force in Precision Ultrasonic Vibration Cutting
Authors: Lu Ze Sheng , Yang L.
Published: March 2009

Precision ultrasonic vibration cutting is a promising technology in field of precision and
ultra-precision machining. It is a kind of the pulsing cutting process with a constant vibration
frequency and sine-wave amplitude of vibration. In this article, a rational model of cutting force in
vibration cutting is established, and the vibration cutting mechanism is analyzed. Specially, by the
method of numerical simulation, the effect regulation of amplitude of vibration on cutting force is
theoretically discussed for the first time in precision vibration cutting. And the relationship between
cutting parameters and cutting force is probed into on the different cutting conditions.
Fabrication of Diamond Micro Tool Array (DMTA) for Ultra-Precision Machining of Brittle Materials
Authors: Zhao Qing Liang , Xie Da Gang , Brinksmeier Ekkard , Riemer Otmann , Rickens Kai
Published: March 2009

A novel conditioning technique to precisely and effectively condition the nickel
electroplated mono-layer coarse-grained diamond grinding wheel of 91m grain size was developed
to fabricate a Diamond Micro Tool Array (DMTA) in ductile machining of brittle materials. During
the fabricating process, a copper bonded diamond grinding wheels (91m grain size) dressed by
ELID (electrolytic in-process dressing) was applied as a conditioner, a force transducer was used to
monitor the conditioning force, and a coaxial optical distance measurement system was used to insitu
monitor the modified wheel surface status. The experimental result indicates that the newly
developed conditioning technique is applicable and feasible to generate required wheel topography
of less than 2μm run-out error and grain geometries. The taper cutting test on BK7 proves the
fabricated DMTA is capable of realizing ductile machining of brittle materials.
Recognition on Rolling Bearing’s Condition of Grinding Machine by Using a Novel Approach-Wavelet Hilbert Marginal Spectrum
Authors: Li H.K. , Ma X.J. , Ren Q.M. , Zhao J.L.
Published: March 2009

Grinding machine condition monitoring is very important during the manufacturing
process. Vibration analysis is usually used to its pattern recognition. But traditional signal analysis
method limits the accuracy of recognition because of non-stationary and nonlinear characteristics. In
this paper, a novel approach is presented in detail for grinding machine fault diagnosis. The method is
based on the new developed Hilbert Marginal Spectrum and wavelet transform, named as
wavelet-Hilbert marginal spectrum (WHMS). A rolling bearing’s pattern recognition of grinding
machine is used to testify the effectiveness of this method, which can accurately detect flaw of the
rolling bearing in early stage. Thus, it can be concluded that this promising method will contribute the
development of grinding machine condition monitoring.
Study of Intelligent Prediction Control of Surface Roughness in Grinding
Authors: Ding Ning , Wang Long Shan , Li Guang Fu
Published: March 2009

A surface roughness intelligent prediction control system during grinding is built. The
system is composed of fuzzy neural network prediction subsystem and fuzzy neural network
controller. In the fuzzy neural network prediction subsystem, the vibration data are added to the
inputs besides the grinding condition, such as feed and speed, so as to improve the dynamic
performance of the prediction subsystem. The fuzzy neural network controller is able to adapt
grinding parameters in process to improve the surface roughness of machined parts when the
roughness is not meeting requirements. Experiment verifies that the developed prediction control
system is feasible and has high prediction and control accuracy.
Hydroxyapatite/Chondoroitin Sulfate Microparticles as Time-Controlled Release Carrier of Proteins
Authors: Watanabe Hajime , Ikoma Toshiyuki , Chen Guo Ping , Tanaka M.
Published: March 2009

Time-controlled releases of proteins from hydroxyapatite/chondroitin sulfate (HAp/ChS)
spherical microparticles were achieved by the addition of zinc cation into the mixture solutions of
HAp/ChS and protein as a novel formulation. The initial bursts of proteins, such as cytochrome c
and bovine serum albumin, were apparently suppressed by the amount of zinc cation, which could
be attributed to the formation of coordinate bonds of zinc cation among proteins and/or ChS
moleculars. The increase of molecular lengths of ChS chains decreased the adsorbed amount of
proteins, which did not apparently affected to the release of proteins.
A Novel Collagen Sponge for Cartilage Tissue Engineering
Authors: Chen Guo Ping , Akahane Daisuke , Kawazoe Naoki , Shirasaki Yoshio , Tanaka M. , Yamamoto Katsuyuki , Tateishi Tetsuya
Published: March 2009

A novel collagen sponge that can protect cell leakage during cell seeding was developed by wrapping all the surfaces except the upside of a collagen sponge with membrane that has pores smaller than cell. The collagen sponge was used for three-dimensional culture of human bone marrow-derived mesenchymal stem cells (MSCs). The cells adhered to the collagen, and proliferated to fill the spaces in the sponge. The cell seeding efficiency was higher than 95%. The MSCs cultured in the collagen sponge in the chondrogenic induction medium supplemented with TGF-β3 and BMP6 expressed genes encoding type II collagen, SOX9 and aggrecan. HE staining indicated the round morphology of differentiated cells and the extracelluler matrices were positively stained by safranin O and toluidine blue. Type II collagen and cartilage proteoglycan were detected by immunostaining with anti-type II collagen and anti-cartilage proteoglycan. These results suggest the chondrogenic differentiation of MSCs. The collagen sponge facilitated cell seeding and chondrogenic differentiation of MSCs, and will be useful for cartilage tissue engineering.
Proliferation Effect of Mandibular Condylar Chondrocytes Given The Static Tension-Stress and/or TGF-β1 In Vitro
Authors: Wang Zhi Qiang , Zhao Zhi He , Song Jin Lin , Fan Yu Bo , Luo Song Jiao
Published: March 2009

The purpose of this study is to study the proliferous effect of mandibular condylar
chondrocytes given static tension-stress and/or transforming growth factor-β1 (TGF-β1) in vitro. The
fourth-passage condylar chondrocytes were harvested for this study, and a pulsatile cellular
mechanical system was used to apply stress on cells. The proliferous effect of condylar
chondrocytes given continuous static tension-stress and/or TGF-β1 were examined by using flow
cytometry. The experiment was divided into two parts. The first part was divided into 20 groups
according to different TGF-β1 dosage (0ng/ml, 0.1ng/ml, 1ng/ml and 10ng/ml) for 0, 6, 12, 18 and
24 hours respectively. The second part was divided into eight groups under continuous static
tension-stress (0 or 5kPa) and different TGF-β1 dosage (0ng/ml, 0.1ng/ml, 1ng/ml, 10ng/ml) for 12
hours. Experimental data was analyzed with repeated interclass analysis of variance The results
showed that chondrocytes which were cultured under different TGF-β1dose combined with 5kPa
static tension-stress had multi-horn morphological characters, including a great quantity of
chondrocytes with division growth.TGF-β1 had a mitogenic effect on rat mandibular condyle
chondrocytes at the concentrations of 0.1 , 1 and 10ng/ml , and the mitogenic effect of TGF-β1 to
condylar chondrocytes were demonstrated after 12 to 18 hours, and the peak of mitogenic effects
appeared at the 18th hour (P <0.05) . The most active mitogenesis happened in the group whose
chondrocytes was under continuous static tension-stress (5kPa) combined with TGF-β1. These
results proved that mechanical stimulus and TGF-β1 in vitro could influence and regulate the
growth of condylar chondrocytes.
Effect of Surface Electrostatic Property on Chondrogenic Differentiation of Human Mesenchymal Stem Cells
Authors: Guo Li , Fan Yu Jiang , Kawazoe Naoki , Chen Guo Ping , Tanaka M. , Tateishi Tetsuya , Zhang Xing Dong
Published: March 2009

In this study, three kinds of photo-reactive polymers, namely positively charged azidophenyl-derived polyallylamine (AzPhPAAm), negatively charged azidophenyl-derived poly(acrylic acid) (AzPhPAAc) and neutral azidophenyl-derived poly(ethylene glycol) (AzPhPEG), were synthesized by introduction of photo-reactive group (-N3) into polyallylamine, poly(acrylic acid) and poly(ethylene glycol), respectively. The structure of the azidophenyl-derived polymers was confirmed by 1H-NMR measurement. All of the photo-reactive polymers can be pattern-grafted on the surface of cells culture plate, which was confirmed by the optical microscopy observation. The contact angle decreased after surface modification by the photo-reactive polymers. Human mesenchymal stem cells (MSC) cultured on the modified surfaces showed different morphology. The cells adhered and spread more on the PAAm- and PAAc-grafted surfaces than on the PEG-grafted surface. The pellets formed on PAAm- and PEG-grafted surfaces in condrogenic differentiation medium were positively stained by safranin O/ fast green. But the pellet formed on PAAc-grafted surface did not show obviously positive staining for safranin O/ fast green. These results indicate that the PAAm- and PEG-grafted surfaces promoted chondrogenic differentiation of MSC.
An Abnormal Liner Fracture about 4 Consecutive Cases
Authors: Sedel Laurent , Raould Agnes , Zadegan Frederic , Hannouche Didier , Nizard Remy
Published: March 2009

The experience of Alumina ceramic liner fixed in a metallic shell is not new ; From 1983 to 1999 , 555 components of this type with a titanium screw in shell design were implanted . Recently a review of the first 117 cases with a mean follow up of 12 years were presented. No ceramic fracture were recorded. In 1989 a new press fit shell fixation system replaced the screw in design; This material was implanted from 1989 to 1997. The shape of the liner was an angle of 5°40’ , a liner in excess of 2 mm .A centraliser to insure the correct setting. The shell thickness was limited in order to allow the grid fixation One fracture of the rim (Shipping) was discovered during revision surgery performed elsewhere for acetabular loosening; This revision was performed 4 years after a trauma with fracture of the patella in a fore board trauma. No other fracture was recorded with this design (over more than 1500 implanted). Starting in 1997 a new press fit socket was introduced with a sand blasted surface covered with HA. To be able to retain the same liners , the thickness of the shell were increased resulting in a thin Alumina component for the small sizes (50 mm for a 32 mm head.) . In 1999 a slight modification of the design were made. Recessed liner of 1 mm , ancillary material with a system to insure as well polyethylene or alumina liner fixation. At the moment 5 fractures of this design were recorded (one coming from another institution).
Sequelae of the Hip Joint Infection Treated with a Modern Alumina-on-Alumina THA
Authors: Yoo Jeong Joon , Kim Hee Joong , Kim Young Min , Yoon Kang Sup , Koo Kyung Hoi , Nam Kwang Woo , Kim Yong Lae , Lee Hyuk Jin
Published: March 2009

Total hip arthroplasty (THA) in patients with sequelae of the hip joint infection is a
technically challenging procedure. In addition, the majority of such patients are less than fifty years
old, so it has been reported that they have higher prevalence of complication and failure of
component fixation. Alumina-on-alumina couplings are an attractive alternative and may offer a
promising option for such young active patients. We analyzed 33 primary cementless alumina-onalumina
THAs (PLASMACUP®SC-BiCONTACT® system incorporating BIOLOX® forte) that had
been performed in patients who had sequelae of the hip joint infection. The average age of the
patients was 37.8 years (range, 19-68 years) and 26 patients were younger than 50 years old. They
were followed-up for more than 5 years (average, 74 months; range, 60-93 months). All hips had no
recurrence of hip joint infection. The mean Harris hip score improved from 59.8 points to 93.5
points. All of the implants had radiographic evidence of a bone ingrowth and no radiological
loosening was found. During the follow-up period, no cup or stem was revised and no periprosthetic
osteolysis was observed. Nonunion of the osteotomized greater trochanter occurred in one hip, but
no postoperative infection or ceramic failure was observed. The 5-year minimum follow-up clinical
results of modern alumina-on-alumina THAs performed in patients with sequelae of the hip joint
infection were encouraging with regard to osteolysis and implant stability. Our findings show that
this alternative articulation offers a reliable solution for these young patients with long-standing
anatomic abnormalities of the bone and soft tissues.
Development of Biocompatible Glues for Minimum Invasive Therapy
Authors: Taguchi Tetsushi , Saito H. , Iwasashi Masashi , Sakane Masataka , Kakinoki S. , Ochiai Naoyuki , Tateishi Tetsuya
Published: March 2009

A biocompatible glue consisting of human serum albumin (HSA) and citric acid
derivative (CAD), named CAD-A glue was developed. CAD was successfully synthesized by the
reaction between citric acid and N-hydroxysuccinimide in the presence of 1-ethyl-3-(3-dimethyl
aminopropyl) carbodiimide hydrochloride. When the CAD-A glue was applied to the collagenbased
casings, it took 7 min to obtain half of maximum bonding strength (760 g/cm2). The bonding
strength of this glue to collagen-based casings increased with increasing of HSA concentration.The
bonding strength of CAD-A glue increased with increasing CAD concentration up to 200 mM, and
then decreased with increasing CAD concentration under the fixed HSA concentration (50 w/w%).
The CAD-A glue showed excellent wound closure ability rather than fibrin glue when applied to the
mouse skin. These results suggested that this developed glue had both tissue compatibility and
bonding strength for use in clinical field.
Fracture Strength of Ceramic Bracket Tie Wings Subjected to Force Direction
Authors: Kim Kyoung Nam , Lee Sang Bae , Kim H.J. , Choi J.S. , Kim Kwang Mahn , Hwang C.J.
Published: March 2009

In this study, the effects of bracket designs and force direction on fracture strength of
alumina bracket were evaluated. Two differently designed alumina brackets (MISO, HT Co., Ltd.,
Seoul, Korea) were tested. Each bracket was bonded with orthodontic adhesive to stainless steel
cylinder. Compressive force was applied to the tie wing of bracket at 30°, 60°, and 90° to the long
axis of the test device. Fracture strengths were assessed by using a universal testing machine
(Instron 3366, Instron Co., Ltd., U.S.A.). Fractured bracket surfaces were examined using SEM.
Statistical analysis was performed by using SPSS 9.0 for Windows program. Paired samples t-tests
and Kruskal-wallis tests were used at P<0.05. The fracture strength ranged from 150 N with the
occlusal wing to 63 N with the cervical wing in bracket A. A significant difference was founded in
fracture strength between the bracket designs and force directions. Based on this result, it could be
concluded that bracket designs and force direction was important rule to improve fracture strength
of ceramic bracket.
Composition Optimization of Zirconia Toughened Alumina for Dental Ceramics
Authors: Ma J. , Zhao K. , Liu C. , Zhang D. , Zhang Xing Dong , Chao Yong Lie , Li Xu Dong
Published: March 2009

The aim of this study was to optimize sintering aids and processing parameters for
zirconia toughened alumina (ZTA) nano-ceramics with optimal properties as dental ceramics.
Additive agents (TiO2, MgO, SiO2), dry pressing forces and sintering temperatures are very
important for preparation of structural ceramics. In the present study, density and Vickers hardness
measurement, SEM, and XRD analysis were employed to investigate the effects of these on the
final products. The relevant results showed that higher pressing force led to an increase in the
density and Vickers hardness of the sintered ceramics. Among the four groups of sintered nanoceramics
with different ratios of alumina and zirconia, and combinations of additive agents, the best
densification was achieved in the sample from Group 2# containing 1.05wt% MgO after sintered at
1450°C, as indicated by SEM observation. XRD analysis confirmed the formation of MgAl2O4 as an
intermediate compound. The existence of TiO2 in the additive agents was in favor of the acquisition
of high densification. The measured values for the density and Vickers hardness indicated that the
sintered ZTA nano-ceramics would be a potential material for dental prosthetic applications.
Abrasivity of Desensitizing Dentifrice Containing Sodium Metasilicate
Authors: Jang S.O. , Lee Su Young , Kim Hae Sun , Chung W.G. , Kim Kyoung Nam , Kim Kwang Mahn , Kim B.I.
Published: March 2009

This in vitro study compared the abrasivity of commercial desensitizing dentifrices with a sodium metasilicate (Na2SiO3) dentifrice using a Surface Profile Method. Dentin specimens were made from the root of extracted human molars. The cervical part of the teeth was sectioned with a diamond wheel disk. The teeth were embedded into an epoxy resin mold and the surface was gradually polished by silicone carbide paper. After grinding, the degree of surface roughness was tested within the range of 2 mm with tapping. The British Standard Institution reference dentifrice (BSI: CaCO3 40%) and experimental dentifrices (group 1: Na2SiO3 25%, CaCO3 10% and SiO2 10%, group 2: CaCO3 10% and SiO2 10%, group 3: CaCO3 10% and SrCl2 10%, group 4: Colloidal Silica 2-3% and Hydroxyapatite 10-20%) were evaluated. The dentifrice slurries were prepared by mixing 24 grams of the dentifrice in 12 ml distilled water. Each tooth specimen was brushed with the dentifrice slurries 1,000 times. The relative abrasivity of each dentifrice was evaluated from the ratio of the BSI standard dentifrice to each experiment. The results were analyzed by one-way ANOVA and Tukey’s multiple comparisons using Window SPSS (Statistical analysis system) 12.0. Groups 1 (71), 2 (74.2), 3 (38) and 4 (7.8) showed a lower abrasivity than the BSI dentifrice (100) (p<0.05). The relative abrasivity of groups 3 (38) and 4 (7.8) was the lowest compared with the BSI dentifrice (100). However, group 1 (71) containing Na2SiO3 showed a similar abrasivity to group 2 (74.2), which did not contain Na2SiO3 (p>0.05). Therefore, Na2SiO3 had no influence on the abrasivity of the dentifrice. In conclusion, the dentifrice containing Na2SiO3 had a lower abrasivity than the BSI reference dentifrice, but showed a significantly higher abrasivity than the existing commercial desensitizing dentifrices. Overall, the relatively high abrasivity of Na2SiO3 dentifrice is believed to be the result of other components in the abrasive system.
A New Method for Evaluating Thermal Compatibility of Multi-Layer Dental Ceramic Composites
Authors: Cui Jun , Ou Jun , Chao Yong Lie , Gao Q.P. , Yin Guang Fu , Wang H. , Shen J.F. , Chen Yang Xi
Published: March 2009

Dental ceramic materials do not always show linear expansion behavior. In general, thermal
contraction behavior of dental porcelain can be described with the polynomial function: L/L= C+α1
T+α2 T2. In addition, a new method for taking into consideration of nonlinear contraction behavior of
dental ceramics is proposed for calculating thermal mismatch value (α) between substrate and
veneering materials. Discs of eight substrate/veneer combinations (n=10) were fabricated for thermal
shock testing. In this study, a stepwise multiple regression analysis was performed to determine the
relationship between thermal shock test results and thermal mismatch value (α) on these
combinations. A high degree of correlation was found between αs-b and T. The new method proves
to be a reliable one to predict thermal compatibility of multi-layer dental ceramic composites.
The Marginal Fit of CAD-CAM Zirconia Cores with Different Proximal Margin Configurations
Authors: Puntsag O.E. , Bae E.K. , Lee Jae Hoon , Lee Keun Woo
Published: March 2009

This study evaluated the marginal fit of CAD-CAM Zirconia cores with different
proximal height. Thirty Zirconia cores and ten metal ceramics crowns were used to evaluate the
marginal gap. The marginal fit was determined to be perpendicular to the tooth axis between the
most apical point on the coping margin (core) and the reference marks on the mesial, distal, labial,
and palatal surfaces of the die at several key stages of crown fabrication; before porcelain built-up,
after body porcelain built-up, and after glazing. Additionally, an opaque stage for the metal ceramic
copings was compared as well. Each measurement was carried out with a microscope. The means of
gaps among the groups were 58±27 -m, 69±23 -m, 89±29 -m and 80±28 -m, groups I, II, III and
IV, respectively. In relation to the proximal and labiopalatal surfaces there were no statistical
difference among the groups, except group I. No significant differences were observed in firing
stages of all groups. The findings of this study showed that the mean marginal gap of Zirconia
cores with different proximal heights fell well within the acceptable clinical ranges.
Preparation of β-Calcium Metaphosphate (β-CMP) Whiskers
Authors: Liao Li , Chen Lin , Chen Ai Zheng , Pu Xi Ming , Kang Yun Qing , Yin Guang Fu
Published: March 2009

To increase the mechanical properties of PLA used for fracture inner fixation, β-calcium
metaphosphate whiskers were prepared by controlled crystallization in the glass. The factors
influencing the morphology of the samples, such as component, time and temperature of
crystallization were discussed. Results showed that the high quality of β-calcium metaphosphate
whiskers can be obtained by crystallization treating for 36 hours and washing for 48 hours at 80°C
distilled water. β-calcium metaphosphate whiskers having high aspect ratios of 20-100 with
diameters of 1-5μm were achieved at the optimized conditions.
Comparison of Biomineralization on Calcium Phosphate Implants in Rabbit and Dog Models
Authors: Xin Ren Long , Leng Yang , Chen Ji Yong , Yang Xiu Dong
Published: March 2009

Porous alpha- tricalcium phosphate (α-TCP) was implanted in rabbit and dog models to
investigate its induction of calcium phosphate (Ca-P) formation. The morphology and structure of
the formed Ca-Ps were examined using scanning electron microscopy (SEM) and transmission
electron microscopy (TEM), respectively. The results showed an animal-dependent behavior of in
vivo Ca-P formation. There were flake-like octacalcium phosphate (OCP) precipitates in the rabbit
but rod-like hydroxyapatite (HA) precipitates in the dog model. In addition, high-resolution TEM
(HRTEM) image revealed that there was OCP structure in certain portions of the rod-like HA
precipitates in the dog model. And the orientation relation of OCP/HA was deduced as OCP
(010)//HA (0 10) and OCP (001)//HA (00 1) . This implied that the in vivo HA was formed via
OCP precursor phase.
A Novel Approach to Prepare Nano-Hydroxyapatite / Silk Fibroin Composite to Increase Nucleation Sites
Authors: Wang Jing , Li Mu Qin , Meng Xiang Cai , Wen Guang Wu
Published: March 2009

A composite of needle-like nano-Hydroxyapatite / silk fibroin (n-HA/SF) with strong interfacial bonding was successfully prepared from calcium chloride (CaCl2) and diammonium phosphate ((NH4)2HPO4) as starting materials of HA in the presence of SF powders dissolved in a ternary solvent system of CaCl2-C2H5OH-H2O (1:2:8 in molar ration) at 80 °C for 30 min prior to preparation of n-HA/SF composite. The n-HA crystals in the composite were poorly crystallized and uniformly distributed in the composite with a crystal size of 4~6 nm in diameter and 20~40 nm in length, which was smaller than that of pure nano-HA. Molecular interaction and strong chemical bonds were formed between n-HA and SF in the composite, which were revealed by Fourier transform infrared spectrometric analysis (FTIR). The synthetic n-HA/SF composite had a good homogeneity and preferential orientation along c-axis and would have a great potential for bone tissue engineering.
Chemical Dissolution and Bone Formation in Identical Porous β-TCP and HA
Authors: Shen Qing Yi , Sun Jiao , Huang Zhe Wei , Zhang Ding Hua , Lu Hua , Gu Guo Zhen , Qian Yun Fang , Lu Jian Xi
Published: March 2009

Porosity and macroporosity in porous calcium phosphate bioceramics play an important role in conducting cells and vessels penetrating into pores and forming bone ingrowth inside bioceramics. Histological results indicated new bone volume (NBV) was higher in β-tricalcium phosphate (β-TCP) implants than that in hydroxyapatite (HA) implants for identical porosity of 75% at both 1 month and 3 months, and the degradation of β-TCP was too quick to keep its original shape at 3 month. According to the XRD analysis, chemical dissolution seemed to be one part of degradable mechanism forβ-TCP
Calcium Phosphate Nano-Composite with Bone Morphogenetic Protein
Authors: Park M. , Kim H. , Lee Jin Woo , Lee Kang Yong , Kim Hyun Min , Moon S.H. , Lee H.M.
Published: March 2009

Thick coatings of bone morphogenetic protein (BMP)-calcium phosphate nano-composite
were prepared by a biomimetic process, in which substrates were immersed in modified simulated
body fluid containing rh-BMP2 at room temperature and pressure. In vitro analyses showed that the
calcium phosphate and BMP formed stable and uniform coating of composite on surface of substrate,
and that the composite derive significant improvement in tissue formation, suggesting an
osteoinductive bioactive surface.