bluuebunny/crossref_metadata_2025 huggingface dataset:
Study of Local Material Removal Model of Bonnet Tool Polishing
Authors: Xie Da Gang , Gao B. , Yao Ying Xue , Yuan Zhe Jun
Published: March 2009

Bonnet tool polishing is a novel aspherical polishing method. This paper describes a
method to obtain the local removal rate for the polishing process using bulbous flexible membrane covered with a polishing pad and pressurized by an internal fluid. According to the principle of bonnet polishing and Preston equation, the local removal rate model was established. It is confirmed by the experiments that the local removal depth has a linear relation with the dwell time. Preston coefficient can be calculated from the experimental data. Finally the expression of the local removal
rate in bonnet tool polishing is acquired semi-empirically.
The Factors Influencing on Cutting Edge Radius of Ultra-Precision Diamond Cutting Tools in Mechanical Lapping
Authors: Zong Wen Jun , Li Dan , Sun T. , Cheng K. , Liang Ying Chun
Published: March 2009

A brittle-ductile transition lapping mechanism is proposed for the mechanical lapping of ultra-precision diamond cutting tools, and then the critical depths of cut for brittle-ductile transition in different orientations and on different planes are deduced in theory. Combined the critical lapping depth with the contact accuracy between rotating scaife and lapped tool surface, the influences of processing factors on cutting edge radius are studied. Both the theoretical analyses and experimental results indicate that the vibration of lapping machine tool and surface quality of scaife have enormous influences on the sharpened cutting edge. And lapping compression force has an optimal value. Lapping rate should be considered when lapping velocity is selected. But the smaller the lapping velocity is, the littler the cutting edge radius sharpened. Finally, the optimal selections are performed for each influencing factor and a perfect diamond tool is lapped in ductile mode with
a cutting edge radius of 30~40nm and a surface roughness Ra of 0.7nm.
Study on Wear Mode of Silicon Nitride Balls in Lapping Process
Authors: Lv Bing Hai , Yuan Ju Long , Yao Ying Xue , Wang Z.W. , Tao B.C. , Zhen J.J. , Zhao Ping
Published: March 2009

To understand the mechanism involved in the lapping process of the silicon nitride balls, the wear mode is investigated in this paper. The abrasion tests were performed on a ball-plate wear test apparatus with different loads (0~2N/ball) and slurry concentrations (5%wt~30%wt W20 B4C3). The abraded surface is observed by optical telescope. A wear-mode map, which defines the regimes
for two-body abrasion or three-body abrasion dominating in the micro-scale abrasion test, is plotted with two axes: load and concentration of abrasive. An empirical formula for the wear mode transition is adopted to calculate the transition point S*, which can then used to predict the wear mode in lapping process of silicon nitride ball.
Development of the 3-PTT Parallel Snagging Machine Tool
Authors: Hu Ming , Guo C. , Cai Guang Qi
Published: March 2009

In this paper, a snagging parallel machine with 3-DOF is presented. It has the dominate merit in layout, structure, controlling manner and an attribute of large working space and easy real-time control. The machine tool achieves the anticipating effect and satisfies the need of the snagging operation.
Nano-Porous Silica (SiO2) and Iron-Silica (Fe2O3-SiO2 ) Composite Synthesis via Reverse Microemulsion for Catalytic Applications
Authors: Jan Lal Said , Shahidan Radiman , Yaacob Iskandar Idris
Published: March 2009

Nanostructured silica and silica-iron composite particles were prepared using water-in-oil (w/o) reverse microemulsion. Double microemulsion technique is used for the synthesis of both types of nanostructured particles. X-ray Diffractometry (XRD), scanning electron microscopy (SEM), nitrogen gas adsorption-desorption isotherm technique, and differential scanning calorimetry (DSC) were used to characterize the synthesized particles. The gas adsorptiondesorption measurements revealed a mesoporous structure for the silica (SiO2) particles with a surface area of 300.49 m2/g. Upon the addition of an iron microemulsion to the silica microemulsion, silica-iron nanocomposite (Fe2O3-SiO2) was achieved which gave a surface area of 69.87 m2/g. This indicated a positive impregnation of the silica mesopores that was further confirmed by energy dispersive spectrometry (EDS). The XRD of bare SiO2 gave a single broad peak whereas SiO2-Fe2O3 demonstrated additional peaks confirming α-iron insertion in mesoporous silica. DSC curve with its characteristic peaks also indicated the presence of iron nanoparticles
within silica. The product silica-iron nanocomposite has potential catalytic and semiconducting applications.
Analyzed by Kelvin Force Microscopy of PbZr0.3Ti0.7O3 Thin Films Grown on La0.5Sr0.5CoO3 or LaMnO3 Bottom Electrodes
Authors: Choi J.S. , Kim J.S. , Byun I.S. , Park B.H.
Published: March 2009

We have investigated structural and electrical properties of PbZr0.3Ti0.7O3 (PZT) thin films deposited by pulsed laser deposition methods. In order to improve the ferroelectric properties of PZT thin films, we have controlled grain size or surface morphology by changing bottom electrode or deposition time. PZT thin films have been deposited on La0.5Sr0.5CoO3 (LSCO) or LaMnO3 (LMO)
bottom electrodes with LaAlO3 substrates during different deposition times. X-ray diffraction data have shown that all the PZT films and bottom electrodes are highly oriented with their c-axes normal to the substrates. The thickness of each film is determined by field-emission scanning electron microscope. We have also observed alternation of grain sizes (80~180 nm) by using atomic force microscopy mode and surface potential distribution and retention behavior of ferroelectric domains
by using Kelvin force microscopy mode. A PZT/LMO structure has shown superior ferroelectric and retention properties to a PZT/LSCO structure.
Flexural Behavior of GFRP Reinforced Concrete Members with CFRP Grid Shear Reinforcements
Authors: Jeong Sang Kyoon , Lee Seung Sik , Kim C.H. , Ok Dong Min , Yoon Soon Jong
Published: March 2009

Nowadays, the investigations relating to the FRP re-bars have been increased due to their superior physical and mechanical properties such as environmental resistance, electro-magnetic transparency, and high specific strength and stiffness. In this paper, we present the results of an experimental investigation pertaining to the flexural behavior of concrete beams reinforced with GFRP re-bar bundles for tension and CFRP grids for shear. A total of eight specimens, two pairs of
four different shear reinforcement spaces, is loaded to failure under the 4-point bending test set-up. In addition to the experimental investigation, theoretical evaluation is also conducted according to the ACI Committee 440 for all beam specimens. Both experimental and theoretical results such as failure
modes and load-deflection relations are compared and good agreements are observed.
An Analysis on Dynamic Damage on Concrete Obstruct Subjected to Underwater Explosion Shock Waves
Authors: Hao Li , Ning Jian Guo
Published: March 2009

Based on the multi-material Eulerian algorithm, the damage effects of concrete obstruct subjected to underwater explosion shock waves are simulated by using the NM-MMIC code which is a 2D multi-material elastic-plastic hydrodynamics code with C++ language. According to the simulation results of underwater explosion, the optimum charge, the damage degree and the damage laws of obstruct are obtained. The simulation results show a good agreement with that obtained by
DYNA2D. Thus the given study indicates that the model and algorithm presented in this paper are reasonable and the simulation method can be used for designing and estimating ammunitions against obstructs in water.
A Study of Application about FLAC-3D in Damage of Rock Mass Slope
Authors: Pan Qi Xin , Chang Lai Shan
Published: March 2009

A damage mechanics model for jointed rock mass is established by the simulation of the multi-cleavage behaviour by introducing the damage tensor and by considering the jointed rock mass as continuous medium with damage. The data exchange technique with FLAC-3D is discussed by applying FISH Language that is inserted in FLAC-3D. The coupling analysis between the rock mass damage and FLAC-3D is realized by the computer program for damage mechanics analysis set up by Visual Basic, which is applied in the simulation analysis of the south slope of Yanqianshan Iron Mine.
Study on Basic Mechanical Behaviors of Rocks at Low Temperatures
Authors: Liu Quan Sheng , Xu Guang Miao , Hu Yun Hua , Chang Xiaoxiao
Published: March 2009

Basic mechanical behaviors of rocks at different temperatures and with different moistures are required to be investigated for studying and designing rock engineering in cold regions. In this paper, two typical rocks, i.e., red sandstone and shale sampled from Jiangxi and Hubei in China, respectively, are tested by uniaxial and triaxial compressive tests at different temperatures ranging from 20°C to -20°C and in dry and fully saturated states. The test results show the different behaviors
of them. The values of the uniaxial and triaxial compressive strengths, Young’s modulus, cohesion, and friction angle, increase with the lowering of the testing temperatures, but the tendencies are different for these two kinds of rock.
Effect of Roller-Working on Fatigue Strength Improvement of Notched Structural Stainless Steel
Authors: Iswanto Priyo Tri , Nishida Shinichi , Hattori Nobusuke , Kawakami Yuji
Published: March 2009

In order to study the effect of plastic deformation on fatigue behaviors of plastically
deformed specimen, bending fatigue tests had been performed on notched deformed stainless steel specimens. Also pulsating fatigue tests were done on notched non-deformed specimens to evaluate the influence of mean stress on fatigue behavior of notched non-deformed specimens. The result showed that according to increase of deformation value, the fatigue limits of these specimens also significantly increase. Fatigue limit of rolled specimen does not linearly increase with increase in plastic deformation value. Based on fatigue limit diagram, the effect of compressive residual stress on fatigue limit improvement of stainless steel is higher than that of work-hardening. In case of non-deformed specimen, when the compressive mean stress increases, the fatigue limit and the number of cycles to failure increase. In case of tensile mean stress, this kind of mean stress decreases the fatigue limit.
Effect of Recrystallization on Low-Cycle Fatigue Behavior of DZ4 Directionally-Solidified Superalloy
Authors: Shi Hui Ji , Zhang Hai Feng , Wu Yan Qing
Published: March 2009

Effect of recrystallization on DZ4 directionally-solidified nickel-base superalloy was
investigated both at room temperature and high temperature of 673K. In-situ SEM surface observation were performed. Experimental results reveal that the material performance is strongly influenced by surface recrystallization layer. All specimens were prepared under conditions of shot peening and 4h 1220°C high temperature annealing. Different shot peening pressure specimens have different recrystallization states. High shot penning pressure specimens have clear and straight grain boundaries and the grain size appears to be a little bit larger.
Recrystallization state seems not only affect the fatigue life, but also the crack initiation pattern and crack initiation life. Low shot peening pressure specimens have much lower fatigue life which is around 8-10% of virgin one, and SEM Real-time observation reveals that channeling cracks initiated at the early stage of fatigue life. High shot peening pressure specimens have higher fatigue life comparing to low shot peening pressure specimens, although it’s almost half lower than the virgin one, and cracks initiated not until middle or latter stage of fatigue life. Crack initiation life is also much longer than those of low shot peening pressure. Low shot peening pressure specimens seems not fully recrystallized, and its grain boundaries are much fragile which is responsible for high density microcracks initiation, and finally leads to the failure. Further nano-indention experiments on surface recrystallized layers show that higher shot peening recrystallized layers have much lower elastic module, which may explain the longer crack initiation life.
Guarantee on Fatigue Reliability of Multi-Layered DLC-Coating Given to CD-Carburized SCM415
Authors: Sato Masato , Suzuki Hideto
Published: March 2009

In this research, surface modification was given to CD (Carbide Dispersion)-carburized steel used for sliding parts of vehicles, and functional evaluation was performed. It developed the DLC-coating which has multi-layered structure according to a UBMS (UnBalance-Magnetron-Sputtering) process as aims at improvement in the tribological properties in the sliding parts for vehicles. In order to
maintain the adhesion with parent material (CD-carburized steel), intermediate layer that gradient hardness was generated. Structure of multi-layered part was made into ten layers. The multi-layered part consists of soft layers and hard layers. A soft layer bears high-ductility and the hard layer bears wear resistance and tribological property. Moreover, as functional evaluation of coating material, it investigated about the friction wear characteristic and influence that a DLC-coating has on the fatigue characteristic.
Slip Line Field Analysis of Unequally Grooved Specimens in Bending and Its Implication to Constraint Toughness Testing
Authors: Kim Yun Jae , Oh Chang Gyun
Published: March 2009

This paper proposes slip line fields for bending of unequally grooved specimens that has a sharp crack in one side and a sharp V-notch in the other side. Depending on the back angle, two slip line fields are proposed, from which the limit moment and crack tip stress fields are obtained as a function of the back angle. Excellent agreements between slip line field solutions with those from detailed finite element limit analysis based on non-hardening plasticity provide confidence in the proposed slip line fields. Based on these results, possibility of designing a new toughness testing specimen with varying crack tip constraint is discussed.
A Viscoelastic Continuum Damage Model for Reinforced Concrete Subjected to Shock Loading
Authors: Ning Jian Guo , Shang Lin , Sun Yuanxiang
Published: March 2009

In this paper, we analyze a RVE of concrete reinforced (RC) with steel reinforcing bar in two vertical directions on basis of the thoughts of composite material and propose that in the ideal case the constitutive equation of reinforce concrete is declared to multiply the viscoelastic constitutive equation of concrete by a reinforcing multiplier G , which is depended on material characters and arrange mode of steel reinforcing bar. In the model, we draw the growing damage law on the assumption that damage only occur in the concrete. Subsequently, we obtain the damage viscoelastic constitutive equation of reinforced concrete. Lastly, the comparison with the plate impact test results of specimens shows that the proposed model can give consistent prediction of the dynamic behavior of SFRC.
An Elongated Tetrakaidecahedral Cell Model for Fracture in Rigid Polyurethane Foam
Authors: Ridha M. , Shim V.P.W. , Yang L.M.
Published: March 2009

A fracture criterion for rigid polyurethane foam is developed based on idealization of
constituent cells by elongated tetrakaidecahedra. The ability of the proposed geometrical model to mimic the fracture characteristics of actual rigid polyurethane foam is examined and a fracture criterion derived analytically. In tandem, the fracture properties of an actual rigid polyurethane foam are obtained from mechanical tests. The fracture criterion based on the model exhibits correspondence with the behavior of actual foam. Consequently, this model constitutes a suitable basis for further investigation into the mechanical properties of actual polymeric foams.
Research of 3D EFG of Limiting Nodal Point Number and Applied for Three-Dimensional Elastic Problem
Authors: Zhang Dun Fu , Zhu Wei Shen , Li Shu Cai
Published: March 2009

The formulation and implementation of three-dimensional element free Galerkin method (3D EFG) are developed. A simple and efficient scheme for a variable domain of influence stipulates that a constant number of nodal points are visible from each integration location is proposed. This method significantly increases the efficiency of the variable domain of influence by limiting the size of the least-square problem that is solved when computing approximate functions. The 3D EFG methods based on moving least square method use only nodal points to built local and global approximation. Discrete model of the 3D EFG for three-dimensional elastic problems is derived by least potential energy principle. Reference to the 2D EFG, in the 3D EFG, it is enforced to meet displacements boundary conditions by use of limiting nodal point number method and penalty method. The stress concentration of a small column-shaped cavity in a cube subjected to uniaxial uniform tension at two opposing faces in far field. Compared the approximation solutions with theory ones, the results indicate that the 3D EFG is validity in solving three-dimensional elastic problems and the limiting nodal point number method is validity.
Thermal Contraction of AA5182 for Prediction of Ingot Distortions
Authors: Suyitno  , Eskin Dmitry G. , Katgerman Laurens
Published: March 2009

Shape distortions and hot cracking during casting are strongly related to thermal contraction during and after solidification. The understanding of this phenomenon is crucial in designing defect-free cast products and in numerical simulation of their thermomechanical behavior. This paper presents the results of experimental and numerical simulation work on the thermal contraction during and after solidification of a commercial AA5182 alloy. In the specially developed experimental set-up, the contraction is measured simultaneously with temperature while the material solidifies and cools down in the solid state. An elasto-viscoplastic constitutive model fitted to experimental data is used in finite element simulations of the contraction process. The implementation of thermal contraction data for ingot distortion during the start-up phase of casting is also included. The results show that the contraction starts at a certain temperature in the nonequilibrium solidification range, close to the non-equilibrium solidus. Good agreement is found between simulation and experimental results.
Effect of OH Content on the Bioactivity of Sol-Gel Derived Glass Foam Scaffolds
Authors: Jones Julian R. , Kemp T.F. , Smith M.E.
Published: March 2009

Bioactive glass scaffolds have been developed with interconnected macropore networks, with pore diameters in excess of 500µm and apertures in excess of 100µm, by foaming sol-gel derived bioactive
glasses. Bioactive glasses bond to bone by forming a hydroxycarbonate apatite (HCA) layer on their surface on contact with body fluid, which is similar to the composition of the apatite in bone. The aim
of this work was to investigate the how changing the atomic structure of the glass affects HCA layer formation. Scaffolds were synthesised at 3 sintering temperatures and were characterised using 29Si and proton MAS-NMR, from which the silica network connectivity and Si-OH groups were quantified. The rate of HCA layer formation decreased as the number of Si-OH groups decreased,
confirming the role of Si-OH groups in HCA layer formation.
Preparation of Porous HA/Beta-TCP Biphasic Bioceramic Using a Molten Salt Process
Authors: Chung Ren Jei , Hsieh M.F. , Huang K.C. , Chou Fong In , Perng L.H.
Published: March 2009

Bioceramics based on calcium phosphate is convinced to be well biocompatible after abundant researches. In this study, a biphasic bioceramic block (10 mm by 5 mm) (BBB) composed of hydroxyapatite and beta-tricalcium phosphate (40/60 in wt%) was prepared using a molten salt approach. At 800oC, the molten sodium chloride well helped the sintering of the precursor powders. A second calcination at 1000oC was then used to evaporate the salt so that a pure biphasic bioceramic block was obtained. This approach can provide porous BBB with 60% porosity, and powder x-ray diffraction patterns ensured the phasic compositions. However, the electrom probe microanalysis showed that around 2 at% of sodium was retained in the BBB. Scanning electron microscope revealed well-dispersed connective micro-pores of 3 micron and random macro-pores of >100 micron in the BBB. Because the salt was evaporated during the preparation of the BBB, the spatial voids were created, and, as a result. The compressive strength of the BBB can only reach a value of 3 MPa. Subcutaneous implantation of the BBB in mice showed that both acute and chronic imflammation were mild. In summary, the molten salt approach is feasible to fabricate biphasic calcium phosphate ceramics having controlled porosity.
A Histological Evaluation of Novel Cyanoacrylate-Based β-TCP Composite in Rat Calvarial Defects
Authors: Lee Sang Bae , Park Kyeong Jun , Lee Doug Youn , Park Jeong Jong , Hwang Jae Sun , Lee Yong Keun , Kim Kyoung Nam , Kim Kwang Mahn
Published: March 2009

In this study, the osteoconductive properties of novel cyanoacrylate-based filling materials for bone defect were evaluated. A new filling material was prepared by mixing Histoacryl® and acid-treated -tricalcium phosphate ( -TCP). Mixing weight ratio of acid-treated -TCP to Histoacryl® was 5:1. 12 male Spraque-Dawley rats were used in this study. The animals were divided
into 4 groups. Critical-sized calvarial defects (8 mm) were created in 9 animals, and then the defects were treated with dense pellet specimen, porous cement-like specimen, and untreated defect for surgical control group. Augmentation treatments were carried out in 3 animals. Histological analysis revealed excellent ostgeoconductive properties of new filling materials. But, some of -TCP particle
in the cement-like group were encapsulated by fibrous connective tissue. For the dense pellet group and augmentation treatment group, shape and stability were better maintained during the implantation time than cement like group. These results indicate that our novel -TCP/Histoacryl® composite have the potential to serve as filling materials for bone defects in the dental and plastic surgery.
Collagen-Calcium Phosphate Hybrids for Bone Grafts: A Novel Route Leading to High Initial Strengths
Authors: Li Xu Dong , Wang Xiao Min , Lin Xiao Yan , Jiang Jian Ming , Zhang Xing Dong
Published: March 2009

An organic/inorganic composite hydrogel route was used to prepare collagen-calcium phosphate hybrids with high mechanical strengths, via in-situ mineral synthesis during collagen fibrillogenesis followed by dehydration. An array of characterization techniques including X-ray diffraction and Fourier transform infrared spectroscopy analyses confirmed that the final products are analogous to natural bone. A three-point bending strength of 70 MPa, much higher than the values reported in the literature, was recorded in the present case, due to the three dimensional network structure achieved between inorganic and organic phases. This innovative method provides an efficient route to produce bone grafts with the desirable mechanical properties which are dependent upon the actual inorganic/organic ratio and water content.
Environmental Phase Stability of Next Generation Ceramic Composite for Hip Prostheses
Authors: Pezzotti Giuseppe
Published: March 2009

A hip-joint femoral head, made of alumina matrix composite, has been evaluated with respect to its surface degradation upon increasing elongation time in water vapor environment. A microscopic evaluation of surface degradation phenomena was obtained according to laser microprobe Raman and fluorescence spectroscopies. According to a confocal configuration of the optical probe, the
spectroscopic assessments were performed in volumes limited to the very neighborhood of the material surface, thus minimizing the effect of the sub-surface, which was less affected by environmental degradation. Two main features were observed: (i) significant transformation of zirconia occurred in moist environment from the tetragonal to the monoclinic polymorph; such an environmentally induced phase transformation, conspicuously increased the fraction of monoclinic
polymorph (i.e., ≅ 18 vol.% in average) already present in the as-received femoral head; (ii) the equilibrium residual stress field stored at the joint surface changed from a tensile field in the as-received material to a slightly compressive stress field after several hours aging in moist atmosphere and, after exposures >50 h to an increasingly tensile stress state. A residual stress field of tensile nature in the joint surface may trigger wear degradation in the femoral head in presence of
microscopic (local) weight impingements due to micro-separation and third-body wear phenomena.
Surface Characteristics and Osteoinductivity of Biphasic Calcium Phosphate Ceramics with Different Sintering Temperature
Authors: Fan Hong Song , Ikoma Toshiyuki , Bao C.Y. , Wang H.L. , Zhang Ling Li , Tanaka M. , Zhang Xing Dong
Published: March 2009

Calcium phosphate (Ca-P) biomaterials have been proved to show osteoinductivity, however the affecting factors and mechanism are still unclear now. In this study, the surface characteristics of biphasic Ca-P ceramics (hydroxyapatite/tricalcium phosphate; HA/TCP) sintered
at the distinct temperature were investigated and the mechanism of the osteoinductivity was discussed. The osteoinductivity of HA/TCP ceramics increased with decreasing the sintering temperature. The different surface micro-structure resulted from different sintering temperature includes phase composition, surface micro-structure, and surface potential. These characteristics
should be the important factors affecting osteoinductivity.
Influence of Phosphate Ions on the Stability of Amorphous Calcium Carbonate
Authors: Akhtar S. , Barralet J.E. , Farrar David , Wright Adrian J.
Published: March 2009

Amorphous calcium carbonate (ACC) occurs with varying stabilities in different organisms. It is thought that the stability is influenced by certain ions and proteins. We describe here a study investigating the particular influence of phosphate ions on the stability of ACC. Synthesised ACC was treated with different concentrations of Na2HPO4 and molar ratios of PO4:Ca ≥ 12:1 were shown to be effective in preventing crystallisation of ACC to calcite. The nature of the resulting
sample is discussed.
31P MAS-NMR Studies of CaO-P2O5 Glass Ceramics
Authors: Dias A.G. , Lopes M.A. , Tsuru Kanji , Hayakawa Satoshi , Santos José D. , Osaka Akiyoshi
Published: March 2009

This work reports the structure of two glass ceramics prepared in the calcium phosphate system, MK5B and MT13B, using 31P MAS-NMR technique. The results obtained showed that the network of MK5B consisted mainly of Q1 and Q2 groups. Besides these two groups, MT13B material also present Q3 units. The Qn groups detected in both glass ceramics seem to be correlated to the crystalline phases present in their microstructure.
An Inverted Observation Technique for Interactions Between Titanium Oxide and Cells on Commercially Pure Titanium
Authors: Watazu Akira , Teraoka Kay , Kido Hirofumi , Okamatsu Kae , Nagashima Yoshiyuki , Morita M. , Matsuura Masanori , Saito Naobumi
Published: March 2009

Commercially pure titanium thin films were uniformly formed on inner surfaces of tissue culture dishes by DC sputtering method. Then, the thickness of the film was about 30nm and the films were thin titanium oxide layer on commercially pure titanium. MC3T3-E1 cells were normally cultured on the dishes. Then, The films on the dishes were not broken and did not decompose. After 24 hours, observations of the sample from the direction of the cells' bottom surfaces adhered the titanium oxide on the commercially pure titanium film by an inverted optical microscope succeeded. Therefore, the new technique is useful for observations the interactions between titanium oxide and cells.
Titanium Oxide (TiO2) Coatings Produced on Titanium by Oxygen-Plasma Immersion and Cell Behaviour on TiO2
Authors: Uzumaki E.T. , Santos A.R. , Lambert C.S.
Published: March 2009

Plasma immersion process was investigated as a method for producing bioceramics
coatings on metallic implants due to its advantages, which include the production of coatings on three-dimensional workpieces, with high density and superior adhesion. In this process, the oxygen plasma was utilized to form titanium oxide on titanium substrate. The structure, composition and surface morphology were studied using scanning electron microscopy (SEM) and X-ray diffraction.
In addition a preliminary study has also been carried out, on TiO2-coated and uncoated titanium substrates, to analyse the in vitro biocompatibility (cytotoxicity evaluation and cell morphology).
Bioactive Non-Woven Silica Fabric Made Through Electro-Spinning Method
Authors: Yoon Hanna , Lee Yong Keun , Lim Bum Soon , Rhee Sang Hoon
Published: March 2009

Non-woven silica fabric was made by electro-spinning method for the application as a bone grafting material. The silica gel, the source material for electro-spinning, was prepared by the hydrolysis of tetraethyl orthosilicate in the presence of water, hydrochloric acid and ethanol. It was transferred to a syringe (spinneret), which was connected to the high voltage supply generating a high electric field between the spinneret and the ground collecting drum. The silica fibers were spun under
the electric field of 2 KV/cm. Their diameters were in the range from about 100 nm to 5 µm. After soaking in the SBF for 4 week, low crystalline apatite crystals were observed to occur partly on their surfaces. From the results, it can be concluded that the non-woven silica fabric made by electro-spinning method has the apatite forming ability in the SBF and it means it has a potential to be
used as a bone grafting material because of its apatite-forming ability, high surface area to volume ratio and high porosity.
Inherent Luminescence of Annealed Biomimetic Apatites
Authors: Müller Frank A. , Müller Lenka , Zollfrank Cordt , Greil Peter
Published: March 2009

Biomimetic apatite coatings are widely used in orthopaedic applications to provide bioinert material surfaces with bioactive behaviour by means of initiating bone growth at the implant surface. In this study we manufactured biomimetic calcium phosphate coatings consisting of a calcium deficient carbonated apatite by immersing activated titanium platelets into simulated body fluid (SBF). The development of the crystal phases was monitored by X-ray diffractometry (XRD) in addition to Fourier-transform infrared (FT-IR) spectroscopy. After annealing in air up to 600 °C luminescence of the biomimetically derived apatite was observed. The photo-induced emission spectra were recorded in the range from 400-750 nm at excitation wavelengths ranging 238 to 450 nm. A blue (437 nm) and a green (556 nm) emission were found between 200 to 600 °C visually appearing white. The results are discussed in terms of chemical and crystallographic changes in the biomimetic calcium phosphate layer during heat treatment.
Calcium Phosphate Coating on AT Titanium Plate by CD and BD Methods
Authors: Yang Xiu Dong , Tang Min , Zhang Bo , Zhao Hui Chuan , Zhang Xing Dong , Chen Ji Yong
Published: March 2009

Bonelike apatite coating on metal implants is an effective method to enhance bioactive properties of the metal surface. In the present study, the effectiveness of cathode deposition (CD) coating methods was investigated. And biomimetic deposition (BD) was also investigated as the parallel. The revised simulated body fluid (R-SBF) was chosen as an electrolyte and simulated body fluid. Both deposition methods could produce bonelike apatite coating on rough surfaces of the titanium. The uniformity of the CD coatings were better than the BD coatings’. And CD method was less sensitive to the condition of the titanium plate surfaces and much faster in the coating deposition. The spectra of FTIR showed that the characteristic peaks of CO3 2- apeared on the surface of ceramics, combined with spectra of XRD and SEM, it was concluded that a sertain thickness of bonelike apatite coating could be formed on the acided treatment (AT) titanium plate surfaces by CD method.
Adhesion of a Novel Calcium Phosphate Cement to Cortical Bone and Several Common Biomaterials
Authors: Grover Liam M. , Gbureck Uwe , Farrar David , Barralet J.E.
Published: March 2009

In this study, we have shown that by incorporating pyrophosphoric acid into a brushite cement system, it is possible to produce a cement that exhibits adhesive tensile strengths with cortical bone, alumina, sintered hydroxyapatite and 316L stainless steel of 700 kPa. To our knowledge, this is the first report of a calcium phosphate cement formulation that exhibits such adhesive properties without the addition of an organic additive. The production of a bond between medical prostheses and bone may further widen the field of application of calcium phosphate cements, additionally the adhesive nature of the calcium phosphate cement may be a desirable ‘handling characteristic’ during reconstructive surgery.
Chemical Composition and Mechanical Properties of Bio-Derived Compact Bone Scaffolds
Authors: Qin Ting Wu , Yang Zhi Ming , Mo Xiang Tao , Luo Jing Cong , Deng Li , Li Xiu Qun
Published: March 2009

To compare the chemical composition and mechanical properties of the bio-derived compact bone scaffold (BDCBS) with the normal compact bone in human. Human compact bone were harvested and divided into control and experimental group. For the latter, BDCBS was prepared with physical and chemical methods. The major components (calcium, phosphorus, collagen protein) and heavy metal contents of the two groups were determined with biochemical assay. Histological examinations were performed to investigate the structure. Cylindroids from the normal compact bone and the BDCBS (6 in each group) were tested under compression. There was no significant difference between the two groups for major components. In addition, there were a few amounts of heavy metal components in BDCBS and control. Histological examinations confirmed the acellular structure in the BDCBS. Results from mechanical testing showed the compressive strength, elastic modulus and ultimate strain (193MPa, 13.76GPa, and 2.3%) of the BDCBS were a bit lower than those (205MPa, 15.67GPa, and 2.5% respectively) of control, but the differences were not statistically significant. In conclusion, there are almost the same matrix structure and composition with similar biomechanical properties between the BDCBS and the control. These results may underscore the potential of the BDCBS in tissue engineering bone.
Influence of Z-Pinning on the Buckling of Composite Laminates under Edge-Wise Compression
Authors: Yan Wen Yi , Liu Hong Yuan
Published: March 2009

Z-pinning is a newly developed technique to enhance the strength of composite laminates in the thickness direction. Recent experimental and theoretical studies have shown that z-pins significantly improve mode I and mode II fracture toughness. In practice, buckling accompanying delamination is a typical failure mode in laminated composite structures. For a complete understanding of the z-pinning technique towards improvements of the overall mechanical properties of laminated composites, a numerical model is developed in this paper to investigate the influence of z-pins on the buckling composite laminates with initial delaminations under edge-wise compression. The numerical results indicate that z-pinning can indeed effectively increase the compressive strength of the composite laminates provided that the initial imperfection is within a certain range. The magnitude of the improvement is consistent with available experimental data.
Eshelby Equivalent Inclusion Method for Composites with Interface Effects
Authors: Duan H.L. , Yi Xin , Huang Zhu Ping , Wang J.
Published: March 2009

The Eshelby equivalent inclusion method is generalized to calculate the stress fields
related to spherical inhomogeneities with two interface conditions depicted by the interface stress model and the linear-spring model. It is found that the method gives the exact results for the hydrostatic loading and very accurate results for a deviatoric loading. The method can be used to predict the effective properties of composites with the interface effects.
Microstructure and Mechanical Properties of ZrB2-Based Ceramics
Authors: Zhang Xing Hong , Hu Ping , Meng Song He , Han Jie Cai , Wang Bao Lin
Published: March 2009

Two ZrB2-based composites were fabricated by hot-pressing with vacuum.
ZrB2+20vol%SiC and ZrB2+20vol%SiC+8vol%TiB2 were selected as the starting compositions. The microstructures and phase constitutions of the composites were investigated and compared to these of monolithic ZrB2 material. For the ZrB2-based composites, with the addition of SiC particles, the excessive growth of ZrB2 materials is restricted and grain structure is refined. Meanwhile the
fracture modes are changed, namely, from transgranular to mixed inter/transgranular. Strengthening mechanism is grain refining and the toughening mechanism is crack deflection, crack branching and grain refining. The role of TiB2 as an addition to the ZrB2 matrix was also examined and discussed.
Microcracking in Monocrystalline Silicon due to Indentation and Scratching
Authors: Zarudi Irena , Zhang Liang Chi
Published: March 2009

This paper discusses the cracking in monocrystalline silicon induced by microindentation with spherical and Berkovich indenters and scratching. It was found cracks always commenced in a specimen’s subsurface beneath the transformation zone. While using a Berkovich indenter the level of the maximum indentation load, Pmax, to initiate microcracking was lower than the case with a
spherical indenter. In both indentation and scratching all microcracks took place at the sites of slip intersection or emanated from the bottom of a transformation zone. The paper also discussed critical loads for microcracking.
Controlled Interphase in Carbon Fiber/Epoxy Composites by Molecular Self-Assembly Method
Authors: He J.M. , Huang Yu Dong
Published: March 2009

In this paper, a new method based on molecular self-assembly on carbon fiber surface was proposed for the improvement of interfacial properties between fiber and epoxy matrix in a composite system. In order to obtain the controlled interphase, the surface of carbon fibers was first metallized by electroless Ag plating, then was reacted with terminally functionized alkanethiols or aromatic thiols to form Ag-thiolate thin films, which further reacted with epoxy resin to generate a strong adhesion interface. The composition, structure and the morphology of the modified carbon fiber surface were examined by X-ray photoelectron spectroscopy (XPS), surface-enhanced Raman scattering (SERS) and atomic force microscope (AFM), respectively. The results showed that these self-assembly molecules were chemisorbed onto the carbon fiber surface coated with silver via the strong S-Ag bond. In addition, these thiol molecules act as coupling agents between the epoxy matrix and carbon fiber through active functional end-groups, such as –OH, -NH2. The interfacial shear strength (IFSS) of the microcomposites after introduced the controlled interphase using the microbond testing was improved.
AZ61 Mg with Nano SiO2 Particles Prepared by Spray Forming plus Extrusion
Authors: Hung Y.P. , Wu K.J. , Tsao Chi Y.A. , Huang J.C. , Hsieh P.L. , Jang Jason S.C.
Published: March 2009

The current study applies the inclusion of thermally stable ceramic nano powders into the light weight AZ61 Mg base alloys via spray forming plus extrusion. The combination of spray forming and severe extrusion provides a new processing route for fabricating nano composites, with uniform distribution of the nano fillers. Parallel tries using the PM route followed by the same severe extrusion can also yield sound composites but the dispersion of the nano SiO2 appears to be less
uniform. The processed composites are characterized in terms of microstructure examination, thermal analysis, phase identification, and mechanical testing.
Adsorption Processes at Solid Surfaces-Studied by Electrokinetic Investigations
Authors: Bellmann Cornelia , Caspari Anja
Published: March 2009

The process of electrophoretic deposition depends strongly on the electrokinetic properties and with it the surface properties of the material that will be processed. Different additives, conditioners but also the suspending liquid influence the surface of the applied material by adsorption. Electrokinetic investigations reflect changes in properties at the outermost solid surface very sensitive. Streaming potential measurements are especially suited for studying such changes of surface chemistry at solids with different shapes. Two approaches are applicable: 1. The adsorption process was done before measuring. The result of this process should be shown. In this case it will be interesting to see differences in the functionality of the solid surface. The zeta potential will be measured versus different pH value. 2. The adsorption process will be studied directly. The zeta potential will be determined versus the concentration of the adsorptive. The second approach can be used for investigation of adsorption of multicomponent mixtures. Competing adsorption processes are detectable.
The Influence of Grinding Parameters on the Superficial Hardening Effect of 48MnV Microalloyed Steel
Authors: Xiao Bing , Park Young Chul , Su Hong Hua , Ding Wen Feng , Fu Yu Can , Xu Jiu Hua
Published: March 2009

The current surface strengthening process of microalloyed unquenched and tempered steel components is usually induction or laser quenching treatment. Subsequent to heat treatment, these structural parts are subjected to grinding, during which impairment of hardened materials can be caused by thermo-mechanical influence of the grinding process. This paper studies a new method of surface heat treatment by making use of grinding heat and stress to create favorable microstructures and promote high wear and fatigue resistance. This work outlines the influence of grinding parameters on the superficial hardening effect of 48MnV microalloyed steel. It was found that the thickness and hardness of the treated surface layer could be up to 1.6mm and HV750 respectively. The beneficial microstructure of the layer was created by an enhanced martensite transformation. It is highly possible that the method can be used to incorporate grinding and surface hardening into a single grinding operation to develop a cost-effective production method.
Research on Ultra-Precision Lapping Technology for Super-Smooth Surface of KTP Crystal
Authors: Lv Bing Hai , Yuan Ju Long , Yao Ying Xue , Wang Zhi Wei , Lou Fei Yan , Zhao Ping
Published: March 2009

The ultra-precision lapping processes to obtain the damage-free surfaces at Å level surface
roughness of Potassium titanyl phosphate (KTiOPO4, KTP) crystal is studied in this paper. The
influence of the lapping parameters on the stoke removal rate and surface roughness and material
removal mechanism in the process of ultra-precision lapping process is discussed, and the evolution
of the lapped surface is also observed with electric telescope. A super-smooth surface of quartz crystal
with roughness Ra 0.8667 Å has been obtained by adopting the fine SiO2 abrasive powders and the
elastic polyurethane pad in this study.
A Study on Ontology-Based Modeling Technologies for the Construction Machinery Conceptual Design Knowledge Management
Authors: Hu J. , Liao W.H. , Dai Yong , Guo H.
Published: March 2009

Few existing systems can support the reuse of conceptual design knowledge due to the lack of satisfying modeling technologies. In the present study, we investigated the ontology-based modeling technologies and apply them to develop a framework of conceptual design knowledge management. The practicability and validity of our framework were then examined in a Construction Machinery Design Knowledge Management System.
Identification Method of Structure Transfer Function for Machine Tools Based on Pseudo-Random Process
Authors: Zhang Qing Song , Zhang W. , Xu Yan Shen
Published: March 2009

The contact rigidity and damping between joints of machine tools could vary greatly
because of the difference of static and dynamic loading conditions. The pseudo-random gashing
cutting is adopted in this paper, which makes the identification of structure transfer function of
machine tools close to actual machining condition and improve the identification accuracy. The
main idea of this method is to decouple the transfer function in two directions based on left edge
and right edge cutting. Therefore, the structure transfer function identification of machine tools in
actual cutting excitation is implemented. Finally, this method is compared with the traditional
transfer function identification based on electromagnetism excitation and the qualified error is
given.
Application of Artificial Neural Net in Defect Image Recognizing of Cutting Chip
Authors: Zhao Yan Ling , Liu Xian Li , Wang Peng , Wang Hai Yang
Published: March 2009

Aiming at the problem of image recognition in the process of defected chip generation of
automatic machining, fuzzy category methods of RBF net and eight neighborhood Euler numbers
are researched in this paper. They are based on fuzzy theory and neural net. The gradient steepest
descent of optimization theory is used and aberration is minimized by step between required output
and actual output. By modifying studying algorithm, recognized capacity is increased. This method
is tested in Matlab platform. It can be concluded that fraction of chip image under sophisticated
surrounding may be recognized accurately through this net.
Influence of Polishing Parameters on Chemical Mechanical Polishing Processes of LiTaO3 Wafer
Authors: Yuan Hui , Wei Xin , Du H.W. , Hu W. , Xiong Wei
Published: March 2009

Lithium tantalite (LiTaO3) possesses a combination of unique electro-optical, acoustic,
piezoelectric, pyroelectric and non-linear optical properties, making it a suitable material for
applications in high frequency, broad width-band SAW and BAW components, filters in television
receivers, etc. The surface quality of LiTaO3 wafers decides the performances of the devices. In this
paper, the technique of chemical mechanical polishing (CMP) was used to polish LiTaO3 wafers.
The influences of the polishing parameters on the CMP processes of LiTaO3 wafers were analyzed
in detail based on the measurement of the material removal rate, surface roughness and topograph
of the polished wafers in different polishing conditions.
Study on Networked Technical Service System Oriented Production Process
Authors: Yu Tian Biao , Gong Ya Dong , Liu Jie , Yu G. , Wang Wan Shan
Published: March 2009

To improve the quality and efficiency of technical service, shorten the producing cycle of product, a new mode of technical service is presented, which is networked technical service based on the multi-Agent technique, network technique and modern communications technique. The architecture and function of the networked technical service system oriented production-NTSS are researched, and the key technologies including multi-Agent system, virtual assembling oriented the process of production and the assignment and rank of technical service information are studied. The workflow of NTSS is discussed, and base on these theories a prototype system is established, and the security, practicability and high efficiency of NTSS are proved.