bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and Lithium Battery Properties of LiM(M=Fe,Al,Mg)xMn2-xO4 Powders by Spray Pyrolysis
Authors: Mukoyama Izumi , Kodera Takayuki , Ogata Nobuo , Ogihara Takashi
Published: March 2009

LiM(M=Fe,Al,Mg)XMn2-XO4 fine powders were synthesized by the ultrasonic spray pyrolysis using metal nitrate solution. LiMn2O4 powders obtained by this method have a spherical morphology with a submicron size. XRD revealed that as-prepared powders were crystallized to spinel structure with Fd3m space group. LiM(M=Fe,Al,Mg)XMn2-XO4 showed enhanced cycling performance at room temperature. Reduced Jahn-Teller distortion of LiMn2O4 by metal doping was responsible for enhanced cycle performance of LiMn2O4.
Analysis of Composite Structures on Barium Titanate Fine Particles Using Synchrotron Radiation
Authors: Hoshina Takuya , Kakemoto Hirofumi , Tsurumi Takaaki , Wada Satoshi , Yashima Masatomo , Kato Kenichi , Takata Masaki
Published: March 2009

The crystal structures of barium titanate (BaTiO3) fine particles with a size around 140 nm were investigated using a synchrotron radiation X-ray diffraction method. The observed diffraction pattern was analyzed by Rietveld method assuming several models. As a result, it is found that the BaTiO3 fine particles have composite structures include (a) a tetragonal region with a constant c/a ratio, (b) a tetragonal region with gradient c/a ratios and (c) a cubic region. In order to estimate these structures, the partial profile relaxation technique was applied in the Rietveld refinement. It is considered that the composite structure is important for the size effect on BaTiO3 fine particles.
Influence of Mineral Admixtures on Crack Resistance of High Strength Concrete
Authors: Liu Shu Hua , Fang Kun He , Li Zeng
Published: March 2009

As high strength concrete (HSC) is widely used in construction, more and more attention has been paid to crack resistance of it. In order to improve crack resistance of HSC, we study the influence of mineral admixtures (ground slag, silica fume and fly ash) on brittleness and characteristic length as crack resistance’ indexes. Testing researches shows, without admixture, crack resistance of HSC is the lowest; when one of the three mineral admixtures added, crack resistance increases dramatically; when two of the three mineral admixtures are added in the concrete, crack resistance increases a little more and it does not change very much no matter which two are mixed; crack resistance comes out the highest when the three mineral admixtures are added in concrete. Mechanism analysis shows, Adding fine and high active ground slag, silica fume and fly ash into concrete can greatly improve microstructure of transition zone, decrease Ca(OH)2, ettringite and porosity in concrete, increase C-S-H gel and greatly reduce the original micro-cracks in the transition zone.
Study on Fractal Characteristics and Performance of Ultrafine Slag Grains
Authors: Tang Ming , Li Xiao
Published: March 2009

Ultrafine slag, which is ground with the process of vertical mill, is tested with the laser granulometric distribution apparatus quickly. The characteristics of granulometric distribution of ultrafine slag are analyzed using fractal theory. The fractal dimension of different fineness powders is tested and counted. The result shows that ultrafine slag powders have self-similar characteristics. With the laser granulometric distribution apparatus, the fractal dimension of its powders might be
tested and counted with the fractal theory and its characteristics might be fast evaluated. The inherent law between powders fineness and activity is studied, and the mathematical model is built with the results. The fractal characteristics of powders might be used to meticulously evaluate fineness of ultrafine powders and be used to describe complexity of powders. The test of activation indicates that the slag fineness appraised by fractal dimension has fine linear relevant characteristic
with its 7 d, 28 d activity.
ECOCEMENT Innovative Cement for Contributing to Sustainable Society
Authors: Tomita Rokuro , Hirao Hiroshi , Tochigi Takashi , Tamashige Takamiki
Published: March 2009

In Japan, a majority of urban waste is incinerated to reduce the volume and the residue (incineration ash) is land filled. Japanese municipalities, however, are confronted with serious shortages of waste landfill sites. To mitigate this situation, Taiheiyo Cement Corporation has developed two technologies, which are Ash Rinsing Process and Ecocement. Incineration ash is a suitable material for cement production because it primarily contains essential chemical components of cement clinker. The problem is that chlorine and heavy metals accompanying primary components cause operational trouble and deteriorate quality and material safety of cement. Ash rinsing technology will be effective to remove chlorine and heavy metals in the ash. Therefore, for municipalities closely located existing Ordinary Portland cement plants, it is the simplest way to use waste incineration ash as a raw material in those cement plants. Ecocemet, on the other hand, will be an attractive option for the municipalities distant from cement plants. Ecocement is defined as cement that is produced from over 500 kg (dry base) waste incineration ash supplemented with other wastes (sludge, etc) per ton of Ecocement. According to the discharged amount of ash, correspondingly scaled Ecocement plant is needed. In Ecocement production process, chlorine in the ash is combined with intentionally added alkalis or heavy metals and is extracted. Extracted metal chlorides are recycled as metal sources. Two types of Ecocement can be used in the fields of ready mixed concrete,
concrete blocks or soil stabilizer. The first commercial plant of Ecocement constructed in Chiba prefecture started operation in April 2001. In July 2002, Japanese Industrial Standard of Ecocement was published. Consequently, Ecocement has become an authorized product in Japan. The second Ecocement plant is now under construction in Tokyo.
Study on Characterization of Hardened Concrete from Water Absorption-Time Curve
Authors: Kyo Eitou , Shimizu Goro
Published: March 2009

The characterization of hardened concrete was analyzed by testing the weight change of water absorption. A simple testing method is submitted and discussed in this paper. As one of the test results, it was reported that the relationship between weight change (at) and time (t) of water absorption test would be well fitted with at=(α×t)/(β+t). Based on the result, laboratory studies of a water absorption test were carried out. Test results were discussed for estimation of mix proportions, compressive strength, and carbonation of different kinds of concrete.
Crack Resistance Analyses on RC Composite Floor Slab
Authors: Chang Peng , Yao Qian Feng , Wang A Ping
Published: March 2009

Cracking behavior of reinforced concrete composite floor slab, which has a significant effect on durability of concrete structures, is studied. Crack resistance of one-way composite floor slab is analyzed during transfer stage, handling stage, construction stage and serviceability stage, and calculation formulas are presented. Precast prestressed plank and topping cast-in-situ concrete layer can be designed as composite floor slab. It is assumed that prestressed unit is in elastic stage under
service loads and hence every stress subentry can be calculated on the base of linear elastic theory and can be added linearly. For two-way composite floor slab, principal tensile stress in concrete is deduced on the base of theory of three-dimensional stress state in material mechanics. In addition, two-way effect on stress and practical distribution pattern of moment and shear force are considered. A number of structure experiment and experiences from engineering practice show that cracking behavior of reinforced concrete composite floor slab is a necessary consideration in design and analysis method shown in this paper is convenient and effective.
Research on Effects of Slurry Additives in Cu CMP for ULSI Manufacturing
Authors: Li X.J. , Guo Dong Ming , Ren R.K. , Jin Zhu Ji
Published: March 2009

In this paper, in order to analyze the oxidation, dissolution and corrosive inhibition effects of additives in the slurry for copper Chemical-mechanical polishing(CMP), the slurry(pH5) with the peroxide as an oxidant, the citric acid as a complexing agent and the benzotriazole(BTA) as an inhibitor is studied. The static etching rate and polishing rate of the Cu-H2O2-Citric acid-BTA slurry are measured. The electrochemical behavior involved in the dissolution and corrosive inhibition of
copper in the solutions containing additives is investigated by the electrochemical impedance spectroscopy (EIS) studies. The surface roughness is measured using ZYGO 3-D surface profiler. It is observed that when the slurry is with only 5wt% peroxide existing, copper is stable and slight etching rate on the copper is produced, and the etching rate is only 8.7nm/min. When 0.6wt% citric acid
presents after adding 5wt% hydrogen peroxide, the etching rate will increase by 5.3 times, with a blue complexing product emerging. When the inhibitor BTA is added, the corrosion will be effectively restrained. From the EIS results, the impedance of copper in 5wt% peroxide solution which is in passivation can be greatly decreased by adding the citric acid as a complexing reagent. And the impedance of copper in the solution containing peroxide and citric acid can be increased by the addition of BTA. The surface roughness of the wafer polished with the slurry of 5wt%
peroxide+0.6wt% citric acid+0.12wt% BTA slurry is Ra 4.7 Å.
Study on Electrolytic-Abrasive Sphere Finishing
Authors: Wang Tong , Liu J.C.
Published: March 2009

Based on the principle of sphere generating and Electrolytic-Abrasive Machining (EAM), a new EAM method —Electrolytic-Abrasive Sphere Finishing is developed. In the experiments, the tubular cathode is covered by unwoven nylon cloth, and the abrasive grains are provided together with electrolyte which flows through the tool electrode. This paper chiefly clarifies the features of this method, the selecting bases for the running specifications and the ways to control low current
density. The experimental results show that the pulse current is conducive to paucity of metal removal, and mirror or quasi-mirror finish can be achieved conveniently.
Numerical Simulation of Magnetic Field Distribution in MAF
Authors: Fang Jian Cheng , Xu Wen Ji , Zhao Zhi Yu , Li H.Y.
Published: March 2009

Magnetic field distribution (MFD) plays an important role in magnetic abrasive finishing (MAF). The mathematical models of the MFD in MAF have been established, and forced behavior of magnetic abrasive (MA) in the magnetic field has been analyzed in this paper. The MFD characteristics of the grooved poles have been numerically simulated, and the distribution law of magnetic force, interaction force and interface pressure have been investigated based on a single
particle. The calculated results show that the MFD in the finishing zone is directly affected by the pole structure and working gap. The mapping function of interaction force and interface pressure corresponds to corner-effect in the peak point of the pole, and the magnetic brush stiffness is changed by the diameter and magnetization characteristics of MA, and the magnetic flux intensity (MFI). The numerical simulations are in a good agreement with the experiments. All of results mentioned above will offer an important method to study further on the finishing mechanism.
Influence of Hold Time on Creep-Fatigue Life and Metallurgical Degradation at High Temperature
Authors: Lim Byeong Soo , Kim Bum Joon
Published: March 2009

This paper investigates the influence of various hold times on creep-fatigue life at 600oC. The relationship between the crack growth behavior and hold time was studied, and a metallurigical investigation to examine the effect of creep was performed. To examine the relationship between creep-fatigue life and microvoids, the fraction of micro-voids/cavity area was analyzed at the crack tip. The crack growth rate of the HAZ was found to be faster than that of base metal while creep-fatigue life was found to be shorter. Finally, it can be stated that the fraction of cavity area, Fca could be utilized for the life prediction under creep-fatigue interaction. As the hold time increased, the creep damage was observed along the prior austenite grain boundaries and inside and boundaries of delta-ferrite.
A Finite Element Analysis for Magnetostrictive Thin Film Structures and Its Experimental Verification
Authors: Cho Chong Du , Lee Heung Shik , Kim Chang Boo , Beom Hyeon Gyu
Published: March 2009

In this paper, a finite element code especially for micro-magnetostrictive actuators was developed. Two significant characteristics of the presented finite element code are: (1) the magnetostrictive hysteresis phenomenon is effectively taken into account; (2) intrinsic geometric feature of typical thin film structures of large length to thickness ratio, which makes it very difficult to construct finite element mesh in the region of the thin film, is considered reasonably in modeling micro-magneostrictive actuators. For verification purpose, magnetostrictive thin films were fabricated and tested in the form of a cantilevered actuator. The Tb-Fe film and Sm-Fe film are sputtered on the Si and Polyimide substrates individually. The magnetic and magnetostrictive properties of the sputtered magnetostrictive films are measured. The measured magnetostrictive coefficients are compared with the numerically calculated ones.
Design and Test of Flapping Device Mimicking Insect Flight
Authors: Syaifuddin Moh. , Park Hoon Cheol , Yoon Kwang Joon , Goo Nam Seo
Published: March 2009

This paper addresses detail design and demonstration of an insect-mimicking flappingwing mechanism composed of LIPCA (Lightweight Piezo-Composite Actuator) and linkage system that can amplify the actuation displacement of LIPCA. The angular amplification of the linkage system can provide various flapping angles by adjusting the actuation point of the LIPCA. The device can generate flapping frequency ranging from 5 to 50 Hz depending on weight of the wing and linkages. Flapping tests using different wing mass, area, and aspect ratio were performed to investigate the flapping performance. The test results were described and compared with the estimation. It was found that changes in wing mass, area, and aspect ratio result in significant variation of natural flapping-frequency.
Power Consumption of Piezo-Composite Actuator at Resonance Frequency
Authors: Setiawan Hery , Yoon Kwang Joon , Park Hoon Cheol , Goo Nam Seo
Published: March 2009

This paper addresses the power consumption of the LIPCA (LIghtweight Piezo-Composite Actuator) device system when electric input was applied at its resonance frequency. The LIPCA device system is composed of a piezoelectric ceramic layer and fiber reinforced lightweight composite layers. Typically, a PZT ceramic layer is sandwiched by a top fiber layer with low CTE (coefficient of thermal expansion) and base layers with high CTE. The advantages of the LIPCA design are weight reduction by using the lightweight fiber reinforced plastic layers without compromising the generation of high force and large displacement, and design flexibility by selecting the fiber direction and the size of prepreg layers. An experimental set-up was specially designed to measure the power consumption of the LIPCA. By measuring the capacitance of the PZT ceramic wafer during the test, the electric power that consumed can be determined. Experimental results revealed a significant increase in capacitance of the PZT ceramic wafer with an increase in the frequency of applied voltage around the natural frequency of the actuator.
Computer Simulation of Human Mandibular Bone Structure by iBone, a Novel Reaction-Diffusion Bone Remodeling Model
Authors: Tezuka Ken-Ichi , Takahashi Akiyuki , Takeda Tomoko , Wada Yoshitaka , Kikuchi Masanori
Published: March 2009

Bone is a complex system with adaptation and repair functions. To understand how bone cells can create a structure adapted to the mechanical environment, we proposed a simple bone remodeling model, iBone, based on a reaction-diffusion system [1]. A 3-dimensional mandibular bone model consisting of approximately 1.4 million elements was constructed from sequential computer tomography (CT) images of a 14-year old female. Both teeth and bone were modeled with
isoparametric voxel elements with Young's Modulus = 20 GPa and Poisson's ratio = 0.3. Both heads of the mandible were fixed allowing rotation and horizontal movement. Teeth were fixed vertically allowing horizontal movements. Incisor, right/left group, and right/left molar biting conditions were simulated. The locations and directions of muscles, and their forces were predicted from the CT
images. Remodeling simulation was performed by 10 sets of finite element method analysis and reaction-diffusion remodeling simulation to obtain internal structure adapted to each loading condition. As a result, the major part of the corpus of the simulated mandibular bone showed similar internal structures under different biting conditions. Moreover, these simulated structures were satisfactorily similar to that of the real mandible. Computer simulation of three-dimensional bone
structures based on CT images will be very useful for understanding the patho-physiological state of bone under various mechanical conditions, and may assist orthopedic doctors to predict the risk and efficacy of surgical therapies.
Numerical Simulation of Coupled Rainfall and Temperature of Unsaturated Soils
Authors: Sun Ji Chao , Gao Quan Chen , Wang Hai Biao , Li Ying Ming
Published: March 2009

As a kind of porous medium made of grains, water and air, under some transfer influences, the soil in some certain atmosphere circumstances has the transfer of heat, water and air, which leads to people’s interesting. The change of temperature influences engineering, such as soils’ consolidation, expansion, grains’ force and pore pressure and so on. The paper gives a coupled numerical simulation of atmosphere rain, temperature of soils and gives the correlation between rain and temperature in unsaturated soils. The different clock of the rain begin in day little influences seepage field, due to the superficial part the sun influences; otherwise the temperature has an great influence on the permeability coefficient and diffusion coefficient.
Two-Parameter Parabolic Mohr Strength Criterion and Its Damage Regularity
Authors: Li Chun Guang , Ge Xiu Run , Zheng Hong , Wang Shui Lin
Published: March 2009

A series of formulas about two-parameter parabolic Mohr strength criterion(2-PP Mohr criterion) are derived. Based on the results of uniaxial tension and uniaxial compression tests, the parameters involved in the criterion can be easily determined, then the criterion in terms of the major principal stress and the minor principal stress is derived, and the damage pattern is also discussed. At last, the formulas about the rupture angle and the friction angle are presented, and their relationship is also given. 2-PP Mohr criterion can describe not only shear but also tensile failure. In this criterion the ratio of the uniaxial compression strength and the uniaxial tension strength is not confined as in Griffith criterion. The formula about the rupture angle provides steady theoretical foundation for determining the direction of crack faces and damage patterns in the computation of macro crack propagation. In fact, Griffith criterion is only a special case of the two-parameter parabolic Mohr
strength criterion proposed in this present paper.
The Study in the Displacement Field near Crack of the Plexiglass by Frequency Domination Method of the White Speckle
Authors: Ji Xin Hua , Xu Fang Yu , Chen Jin Long , Qin Yu Wen
Published: March 2009

The fracture properties of Plexiglass bright the attentions of the researchers as it is the import material used in aero-planes industry The white speckle technique could obtain displacement fields nondestructively under the normal environment. Compare to the laser speckle method there are no interference light source and the vibration isolation needed. In the paper the principle of the technique is described and the displacement field near crack and SIF are measured. The results show that the technique is very suitable to the application in industry.
Finite Element Modeling for Static and Dynamic Analysis of Structures with Bolted Joint
Authors: Kwon Young Doo , Kwon Hyun Wook , Hwangbo Ji-Hoon , Jang Suck Ho
Published: March 2009

To predict the accurate behavior of bolted joints, detailed 3-D modeling is needed that considers the contact friction, preload, and nonlinear behavior of joints. However, a detailed model with gap elements cannot ensure convergence due to the complicated shape, plus it is inappropriate for a dynamic analysis. Accordingly, this paper suggests three kinds of model for structures with bolted joints: (1) detailed model, (2) practical model, and (3) simple model, which can be selected based on the purpose of the analysis. Through a static experiment using a strain gauge, the accuracy of the detailed model was verified, and the results of a modal test compared with the results of the simple model to confirm its effectiveness in a dynamic analysis. In the case of a static analysis using the simple model, the analysis results almost corresponded with those of the detailed model for a part 2.5d away from the center of the bolt. Among the proposed models, the simple model has the least degree of freedom and requires 59% less memory than the detailed model.
Prediction of Effective Mechanical Properties of Reinforced Braid by 3-D Finite Element Analysis
Authors: Cho J.R. , Song J.I. , Choi J.H.
Published: March 2009

The numerical prediction of the effective mechanical properties of the reinforced braid inserted in automobile power steering hose is addressed. The key role of the reinforced braid layer is to suppress the excessive radial expansion of the hose subject to high pressure and temperature. The reinforced braid layer is in the structure composed of wrap and fill tows inclined to each with the specific helix angle. In order to predict the effective mechanical properties, we construct a 3-D
finite element model of the unit cell (or RVE) of the reinforced braid in a periodic pattern, in which the detailed geometry of individual fiber tows is fully modeled. By making use of the superposition method and the 3-D finite element analysis, the effective mechanical properties are predicted. Numerical experiments illustrating the theoretical work are also presented.
Effect of Manganese Addition on Strength and Fracture Toughness in Mg-6Al-1Zn Alloy
Authors: Sasaki Taisuke , Uesugi Tokuteru , Takigawa Yorinobu , Higashi Kenji
Published: March 2009

The effect of manganese on strength and fracture toughness was investigated using five kinds of Mg-6Al-1Zn alloys. From the experimental results, the yield strength increased with increasing in manganese content until manganese content reached 0.14 wt. %. On the other hand, further increase in yield strength was not observed in case larger than 0.14 % of manganese was added. In addition, fracture toughness decreases with increasing manganese content. Fracture of magnesium alloy was ductile fracture by void coalescence. Adding excessive amount of manganese caused the increase in the presence of inclusions. This kind of particle easily became the nucleus of microvoid. As a conclusion, manganese should be added so that coarse manganese-bearing particle is not formed. Thus, 0.14 wt. % of manganese should be added to Mg-6Al-1Zn alloy in order to develop the alloy with well-balanced relationship between strength and fracture toughness.
Formation of Ni3Nb and Influence of Y2O3 on Mechanical Properties of Nano-Grained Ni20Cr20Fe5Nb1Y2O3 Alloy
Authors: Kim Il Ho , Kim Yong Hwan
Published: March 2009

The effects of adding Y2O3, and the precipitation of Ni3Nb by heat treatment, on the
mechanical properties of mechanically alloyed Ni20Cr20Fe5Nb alloy were studied. The addition of Y2O3 caused an increase in the tensile strength at room temperature, 400°C and 600°C. The difference in the tensile strength between the Ni20Cr20Fe5Nb and Ni20Cr20Fe5Nb1Y2O3 alloys decreased gradually with increasing test temperature. The tensile strength of the Ni20Cr20Fe5Nb1Y2O3 alloy at relatively low temperature was increased by the addition of Y2O3, but decreased abruptly at temperature above 600°C. This seems to result from a change in the deformation mechanism due to the ultra-fine grain size, that is, grain boundary sliding is predominant at temperatures above 600°C while internal dislocation movement is predominant at temperatures below 600°C. Following the conventional heat treatment of the solution and subsequent aging, only a small amount of δ(Ni3Nb) phase was formed in the Ni20Cr20Fe5Nb alloy, whereas in a previous report it was indicated that a large amount of γ″(Ni3Nb) was formed in IN 718 alloy. The small amount of δ(Ni3Nb) phase formed in the present case is due to the exhaustion of the Nb content resulting from the formation of NbC during consolidation.
Effect of Mixing Ratio on Mechanical Properties of Wide-Gap Brazed Ni-Based Superalloy with Ni-Si-B Alloy Powder
Authors: Kim Yong Hwan , Kim Ki Tae , Kim Il Ho
Published: March 2009

This study investigated the microstructure and mechanical properties of a wide-gap region brazed with various powders mixing ratios of additive powder to filler metal powder. The IN738 and BNi-3 alloy powders were used as additive and filler metal powder for the brazing process. The wide-gap brazing process was carried out in a vacuum of 2×10-5 torr. It was observed that the region brazed with only filler metal had a microstructure consisting of fully eutectic and dendrite structures. However, the region brazed with 60wt.% IN738 additive powder consisted of IN738 additive,
Ni3B-Ni eutectic and (Cr, W)B. The fracture strength of the wide-gap region (70 wt.% additive and 30 wt.% filler metal powder) was as high as 687 MPa at room temperature. The Cracks in the wide-gap brazed region initiated at the Ni3B-Ni eutectic and (Cr, W)B, and then propagated through them. It was found that the Ni3B-Ni eutectic and (Cr, W)B in the brazed region are important microstructural
factors affecting the mechanical properties of the wide-gap brazed region.
Sintering Effect on Mechanical Properties of Composites of Hydroxyapatite Lanthanum Oxide (HA-La2O3)
Authors: Oktar Faik N. , Ozyegin L.S. , Meydanoglu Onur , Aydin H. , Agathopoulos Simeon , Rocha G. , Sennaroglu B. , Kayali E.S.
Published: March 2009

Composites of calcinated bovine bone derived hydroxyapatite (HA) with 0.25, 0.5, 1, and 2 wt % La2O3 were prepared by sintering. The experimental results indicated that compression strength and microhardness of HA-La2O3 composites increase when the content of La2O3 and sintering temperature increase. The best mechanical properties were achieved after sintering at 1300°C. The results are in agreement with densification measurements and microstructure analysis.
Spatially Resolved Raman Spectroscopy for In-Depth Non-Destructive Residual Stress and Phase Transformation Assessments in 3Y-TZP Bioceramics
Authors: Tochino Shigemi , Zhu Wen Liang , Sawada Takeshi , Ikeda Junji , Pezzotti Giuseppe
Published: March 2009

A non-destructive assessment of phase transformation and residual stress is presented for a 3 mol.% Y2O3 added ZrO2 ceramic using Raman microprobe spectroscopy. Low CIP pressure has been selected in the sample procedure to increase a potential to transform ZrO2. Aging tests were made and the transformation depth and residual stresses caused by transformation were evaluated by Raman spectroscopy A Raman microprobe technique using a visible wavelength laser coupled with a confocal optical device may enable one to retrieve spatially resolved information along the material subsurface. To demonstrate the potentiality of the confocal technique, aging of a ZrO2 sample has been made in autoclave and phase transformation gradually promoted from the surface towards the sub-surface of the sample (up to ～60 µm, in a sample autoclaved 168 h). Then, a quantitative spatially resolved assessment was attempted on these samples from their surface. The confocal information from the subsurface was compared with results of Raman spectroscopy collected from a cross-section. Accordingly, a quantitative equation was proposed, which allows the quantitative assessment of the thickness of the surface layer, which underwent phase transformation in ZrO2 ceramics, according to in-depth non-destructive assessments.
Investigations of an Alumina Ceramic with Zirconia Gradient for the Application as Load Bearing Implant for Joint Prostheses
Authors: Oberbach Thomas , Ortmann Claudia , Begand Sabine , Glien Wilfried
Published: March 2009

Abstract. A new ceramic material for orthopaedic applications was investigated. Therefore a gradient ceramic was prepared with a zirconia gradient within an alumina matrix by an infiltration process. This material was characterized regarding its microstructure, stress distribution inside the ceramic, zirconia phase analysis and strength. It could be shown that the flexural strength of the new ceramic is twice as high as of pure alumina ceramic. By this and the low monoclinic zirconia
content this material offers a potential for its use in high load bearing implants like hip heads for joint endoprostheses.
Zirconia Knee Wear and Raman Spectroscopy Studies Compares 3.5-Mrad and 7-Mrad UHMWPE Inserts
Authors: Tsukamoto R. , Pezzotti Giuseppe , Ogino M. , Shoji H. , Asano T. , Nakamura Takashi , Clarke Ian C.
Published: March 2009

We studied the long-term wear behaviour of alumina-doped zirconia femoral condyles against ultra-high molecular weight polyethylene (UHMWPE) tibial inserts. The simulator kinematics included 20 degrees of flexion/extension, ± 5 degrees of internal/external rotation, and 6 mm of anterior/posterior translation. All knee components were subjected to 10 million cycles of normal walking (2.6 KN max, freq. 1.8 Hz). Lubricant was 50% alpha-calf serum (20 mg/ml protein) with EDTA. The tibial inserts were from one lot of ram-extruded UHMWPE and sterilized with 3.5-Mrad or 7-Mrad radiation dose. Soak controls were stored unloaded in deionised water for 60 days prior to testing. Implants were studied with high-resolution confocal Raman spectroscopy after 10-Mc duration. The wear of control knees (CoCr/3.5-Mrad) averaged 4.5mm3/Mc while the wear with the ZrO2/7-Mrad combination was unmeasurably low even after 10 million cycle duration. Raman Spectroscopy at 10-Mc duration showed only the presence of the desired tetragonal phase. Thus, the ZrO2/7-Mrad bearing combination should prove excellent for active patients who may otherwise risk high wear rates over many years of use.
Preliminary Result of THA Using Interface Bioactive Bone Cement Technique Combined with Third Generation Cementing Technique
Authors: Fujita Hiroshi , Miyata Masahiko , Nagahara Ryouichi , Okumura Tomoo
Published: March 2009

29 cases of primary total hip arthroplasty (THA) using interface bioactive bone cement technique (IBBC) combined with third generation cementing technique were evaluated clinically and radiologically. The present study includes 2 men 2 cases and 24 women 27 cases with an average age at operation of 63 years old (ranging 42 to 81). Mean postoperative follow up period was 17.3 months (ranging 12 to 23 months). Pre- and postoperative (1 year) evaluation using Japan Orthopaedic Association (JOA) hip score were 36.0, and 85.0 points, respectively. Postoperative cementing grade using Barrack’s classification was A in every case. At one year, radiolucent line at bone-cement interface was not observed, except one case of rheumatoid arthritis patient at zone 3 (Delee and Charnley) in the acetabular side. Neither osteolysis nor loosening was observed in every case. No major complications, such as infection, dislocation, pulmonary embolization, were observed. The present study revealed excellent short-term result was obtained by IBBC technique combined with third generation cementing technique for primary THAs.
F-Substituted Carbonate Apatite for Promoting Bone Formation
Authors: Sogo Yu , Yokoyama Daiki , Ito Atsuo , Yamazaki Atsushi , LeGeros Racquel Z.
Published: March 2009

Abstract. Fluoride (F-)-substituted type-B carbonate-containing hydroxyapatites (CHAPs) were prepared as bone substitutes with a F-releasing ability. The F- contents in the F-substituted CHAPs were 16-22 times larger than that in normal adult human bones. The carbonate contents in the F-substituted CHAPs corresponded to that in human bones. The F-substituted CHAPs released F- in
an acetic acid – sodium acetate buffer at pH 4.9; within only 3 h, the F- concentration in the buffer increased to more than 63.9 µg L-1, which was 1.5~8.9 times higher than that in a body fluid of normal adult humans. Although the F- concentration rapidly decreased probably due to the precipitation of a certain phase containing F-, the F-substituted CHAPs exhibited the ability to
increase the F- concentration in a body fluid by bone resorption. Therefore, it is expected that the F-substituted CHAPs will be feasible as a F-releasing material for promoting bone formation.
Sintered Hydroxyapatite / Bioactive Glass Composites: Thermal Analysis and Bioactivity
Authors: Chatzistavrou Xanthippi , Chrissafis K. , Kontonasaki Eleana , Zorba T. , Koidis Petros , Paraskevopoulos Konstantinos M.
Published: March 2009

Three-dimensionally ordered materials containing hydroxyapatite (HAp) as well as
Bioglass® (BG) have been prepared in form of pellets and have been examined the effects of BG addition -in combination with a heat treatment process- on biological properties of composite HAp/BG. The investigation of the bioactive behavior of sintered and unheated biphasic mixtures and the deviations from pure HAp was performed by FTIR spectroscopy and Differential Thermal
Analysis. It was observed the appearance of new phases on sintered composite pellets, while a faster biological HAp layer formation was detected, on the composite unheated pellets’ surface than on pure HAp and sintered composite pellets, currently leading to increased bioactivity.
Evaluation of Natural Calcium Carbonate with Surface Modification as a Bone Graft Substitute
Authors: Park Jin Woo , Lee Chung Ho , Choi Byung Ju , Suh Jo Young
Published: March 2009

The objective of this study was to evaluate the biocompatibility and effects of the
particulated and surface modified Ostrich eggshell (OES) as bone graft substitutes in healing of calvarial defects in rats. Additionally we compared the bone forming ability of the surface modified OES to that of BioCoral (Inoteb, France), which has the same chemical compositions as OES, calcium carbonate (CaCO3). Surface modified OES particles were fabricated by alkaline etching
(microroughened-OES) and biomimetic calcium phosphate coating (CaP coated-OES). 3-(4,5- dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay was performed to evaluate cell viability at 1, 4, and 7days using ROS 17/2.8 cells, a rat osteosarcoma cell line. To evaluate the bone forming ability, surface modified OES and BioCoral were filled in the calvarial defects of
fourteen adult male Sprague-Dawley rats. After 4 weeks of healing, animals were sacrificed and evaluated histologically and histomorphometrically. The MTT assay indicated the increases in viable cell numbers of all groups according to the time, and significantly increased cell numbers were observed on CaP coated-OES and BioCoral at 7 day (P<0.01). The histomorphometric results
showed that significantly increased amount of new bone formation in the microroughened-OES, CaP coated-OES, and BioCoral grafted defects compared with unfilled defects (P<0.0001). The degree of ossification was most prominent in CaP coated-OES grafted defects. The results of this study suggest that surface modified OES particles are biocompatible and yield favorable bone
formation in rat calvarial defects. In conclusion, surface modified OES grafts may be considered as effective osteoconductive grafting materials, but further studies are needed to produce more optimal surface modification and confirm long-term results.
Variation in Composition of Bone Surrounding Implants
Authors: Suwa Taketoshi , Sakae Toshiro , Nakada Hiroshi , LeGeros Racquel Z. , Kobayashi Kihei
Published: March 2009

Our studies previously demonstrated that new bone formed around implants can be classified into 3 or 4 types based on tissue structure and composition. Results of the present study, using polarized light microscopy, and microscopic Fourier transform infrared spectroscopic imaging (micro-FT-IR) and micro-XRD to examine different areas in the peri-implant new bone, suggest differences in crystallinity
(crystal size) between pre-existing bone and peri-implant new bone.
Apatite Formation Behavior on Tricalcium Phosphate (TCP) Porous Body in a Simulated Body Fluid
Authors: Uchino Tomohiro , Ohtsuki Chikara , Kamitakahara Masanobu , Tanihara Masao , Miyazaki Toshiki
Published: March 2009

Apatite formation behavior of tricalcium phosphate (TCP) ceramics with different
phases and porosity was investigated in a simulated body fluid (SBF, Kokubo solution). The pure α-TCP with 80% porosity did not form hydroxyapatite (HAp) on its surface after soaking in SBF for 7 days. On the other hand, the pure α-TCP with 20% porosity formed HAp on its surface after soaking in SBF within 7 days, and the biphasic TCP, which consisted of mixture of α-TCP and β-TCP and had 20% porosity, formed HAp within 1 day. The low porosity and coexistence of
α-TCP and β-TCP phases in TCP ceramics were effective for apatite formation in SBF.
Surface and Bulk Contributions in the Crystallization Process of a Bioactive Glass
Authors: Chatzistavrou Xanthippi , Kontonasaki Eleana , Chrissafis K. , Zorba T. , Koidis Petros , Paraskevopoulos Konstantinos M.
Published: March 2009

Bioactive glasses have attracted considerable interest in recent years. In this work, Differential Thermal Analysis (DTA) measurements were performed on bulk and powdered samples of the SiO2-Na2O-CaO-P2O5 glass system, in order to study the particle size effect on the crystal growth and nucleation process. A shift of the crystallization peak to lower temperatures and deconvolution of a slightly asymmetric crystallization peak into two separate peaks were observed with decreasing particle size. The bioactive behavior -through the process of immersion SBF- of the specific glass is studied as a function of particle size. A better bioactive response was observed increasing particle size until a specific size, further increase leading in no further improvement in the bioactive behavior.
Apatite-Forming Ability of Glass-Ceramics Containing Whitlockite and Diopside in a Simulated Body Fluid
Authors: Kamitakahara Masanobu , Ohtsuki Chikara , Kozaka Yuko , Tanihara Masao , Miyazaki Toshiki
Published: March 2009

Tricalcium phosphate (3CaO⋅P2O5, TCP) is known as a biodegradable material and already used clinically as important bone-repairing materials. However, the control of its bone-bonding ability, i.e. bioactivity, and biodegradability is not easy. On the other hand, diopside (CaO⋅MgO⋅2SiO2) ceramic shows a potential of direct contact with bone and high mechanical strength, but low biodegradability. We
expected that a glass-ceramic containing TCP and diopside show high bioactivity and high mechanical strength, as well as biodegradability. Glasses with composition x(3CaO⋅P2O5)⋅(100-x) (CaO⋅MgO⋅2SiO2) (x = 0, 38, 50, 60 mass%) were prepared. They were pulverized and the compacts of the resultant
powders were heated to obtain the glass-ceramics. Only diopside was precipitated at x = 0 in the glass composition, whitlockite (β-TCP) and diopside were at x = 38, 50 and 60, when the compacts were sintered at 1200 °C. The prepared glass-ceramics formed apatite on their surfaces in a simulated body
fluid (SBF). This indicates that these glass-ceramics have a potential to show bioactivity.
Electrochemically Bioactivating of Titanium Surface with Modulation of Citrate
Authors: Zhang Qi Yi , Leng Yang , Fan Hao Jun , Chen Ji Yong , Zhang Xing Dong
Published: March 2009

The electrochemical cathode bioactivating titanium with additive of citrate was reported. After the treatment, there was a uniform dense layer with very tiny granules on the surface of the titanium, this layer was composed of amorphous calcium phosphate-citrate (ACP-CIT) with a thickness of about 150nm. After immersion in saturated calcium phosphate solution, the morphology at different time points of the early stage was quite different. The changes of morphology showed that the citrate in amorphous calcium phosphate modulated the crystal growth.
Biosynthesis of Low Molecular Weight Bacterial Cellulose
Authors: Feng Yu Hong , Wang Xi Bin , Lin Qiang , Wu Zhou Xin , Pang Su Juan , Yin Xue Qiong
Published: March 2009

The biosynthesis of low molecular weight bacterial cellulose (LMBC) by Static culture of Acetobacter xylinum HN001 has been investigated. The medium was prepared with coconut-water by adding sugar and N-compounds. Several conditions effected LMBC yields, such as start pH value of culture medium, culture temperature and culture time were investigated. In view of high yield of LMBC, the optimal culture time and culture temperature was about 70 hours and 32°C with yield of LMBC 1.2g/L. Molecular weight (MW) and molecular weight distribution
(MWD) of LMBC were tested by GFC. Results showed that, though the start pH value of culture medium varied from 3.5 to 5.5, the MW of the product cellulose varied not notable and MWD of LMBC were all almost 1.3.
Tooth Whitening Effect of Toothpastes Containing Nano-Hydroxyapatite
Authors: Kim B.I. , Jeong S. H. , Jang S.O. , Kim Kyoung Nam , Kwon H.K. , Park Yong Duk
Published: March 2009

The aim of this in vitro study was to evaluate the tooth whitening effect of toothpaste containing nano-sized hydroxyapatite (HA). There were 3 types of dentifrices, which had a different level of abrasive components. For group 1, a newly developed toothpaste containing Nano-sized hydroxyapatite (Nano-HA) was used. Commercially available toothpastes were used in groups 2 and 3. Group 2 used toothpastes containing silica and multi phosphate. Group 3 used toothpastes
containing abrasives with silica and micro-sized HA. In order to simulate 6-months of tooth brushing, the tooth specimens in all 3 groups were placed on a V8 Cross Brushing Machine (Sabri Co. U.S.A.) and brushed 10,000 times with the toothpaste slurries. The tooth specimens were then soaked in artificial saliva for 24 hours to create conditions similar to those encountered in vivo. The
whitening efficacy was assessed before and after tooth brushing using the VITA shade scores of Shadeeye-EX NCC Dental Chroma meter (Shofu Co. Japan). All toothpastes produced significant differences in the mean shade change in the teeth before and after tooth brushing (p<0.05). However, there were no significant differences in the change in the shade between each group (p>0.05). Although the new Nano-HA toothpaste did not have superior whitening effects to the
commercially available whitening toothpastes, they had a similar whitening efficacy to
commercially available whitening toothpastes. These effects might come from the physical properties of Nano HA, which increase the surface dimension more than the Micro-sized HA and have the potential of remineralization.
Deposition of Bone-like Apatite Layers on the Surface of Poly(L-Lactic Acid) Using Immobilized Urease
Authors: Unuma Hidero , Ito Akihiro
Published: March 2009

Particulate layers of hydroxyapatite were deposited on the inner and outer surfaces of porous poly(L-lactic acid) monolith, PLLA, by using enzymatically derived ammonia as the precipitant. PLLA specimens were surface-modified with urease and were impregnated with aqueous solutions containing Ca2+, PO4
3- and urea. As ammonia was produced by hydrolysis of urea with the aid of the urease, hydroxyapatite precipitated predominantly on the surfaces of the porous
PLLA. In contrast to the conventional biomimetic method or the alternate soaking method, it took shorter time period for hydroxyapatite particles to cover the surfaces of PLLA. The resultant hydroxyapatite was proved to be bone-like apatite because it had low crystallinity, contained carbonate ion in the lattice, and had a calcium-deficient composition.
Attachment and Proliferation of Human Periodontal Ligament Fibroblasts on Fibronectin-Coated Bioactive Glass Modified Ceramics
Authors: Kontonasaki Eleana , Sivropoulou A. , Papadopoulou Lambrini , Garefis P. , Paraskevopoulos Konstantinos M. , Koidis Petros
Published: March 2009

The effect of fibronectin (FN) on human periodontal ligament fibroblasts (PDLF)
attachment and proliferation on Bioglass® (PerioGlas® Synthetic Bone Graft Particulate, US Biomaterials) modified dental ceramics, was investigated in vitro. FN introduced limited alterations in cell attachment on Bioglass®-modified dental ceramics in comparison with the corresponding non-FN-coated specimens but had a profound positive effect on Bioglass®-coated specimens that weakly supported both cell attachment and proliferation. The amount of protein adsorbed on the specimens was not proportional to its biological activity, i.e. cell attachment, spread and
proliferation, probably due to surface energy variations and FN conformational changes induced by differences in surface composition and morphology of the different dental ceramics modifications.
Development of Bioactive Organic Polymer Coated with Ceramic Thin Films Synthesized from Aqueous Solution
Authors: Sato Koji , Onodera Daisuke , Hibino Mitsuhiro , Yao Takeshi
Published: March 2009

Poly methyl methacrylate(PMMA) with mar resistant or poly ethtylene(PE) substrates were surface-treated by applying plasma discharge or alkaline solution. Ceramic thin film comprised of silicon oxide, titanium oxide and zirconium oxide was formed on these surface treated substrates respectively from an aqueous solution, and after the formation of ceramic thin film, titanium oxide thin film was also coated on them from aqueous solution at ordinary temperature and pressure. The thin film coated polymer material was tested in mechanical property. The thin film
was hard and the adhesion strength to the organic polymer substrate was very high. The substrate was soaked in SBF and apatite was formed on the substrate. This method is promising for developing hard and soft tissue implants with various mechanical properties as well as high bioactivity.