bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of Tensile Fracture Behavior between Si-Ti-C-O Fiber Bundle (Yarn), Woven Fabric of Yarn and Laminated Composite of the Si-Ti-C-O Fabric / Mullite Filler / Polytitanocarbosilane System
Authors: Maeda Tomoyuki , Hirata Yoshihiro , Sugimoto Joe , Sameshima Soichiro , Yoshidome Toshifumi , Shibuya Masaki
Published: March 2009

A polytitanocarbosilane (20-30 mass%)-xylene solution was infiltrated into a porous laminated composite with 35-40 vol% Si-Ti-C-O fabric of 11 diameter fiber and 15-25 vol% mullite filler, and decomposed at 1000°C in an Ar atmosphere. This polymer impregnation and pyrolysis method was repeated 8 times to produce the composites of 76-82 % theoretical density. The yarn (662-765
filament / yarn), fabric and composite provided the following average strengths : 1240 MPa for the yarn; 768 MPa for the fabric; 117 MPa for the composite. The fracture probability of the yarn, fabric and composite was well fitted by the normal distribution function. The tensile strength of the composite was interpreted by the product of the effective fiber content, the Young's modulus of the fiber and elongation of the composite.
Measurements of Microscopic Stresses in Si-Based Polycrystalline Ceramics
Authors: Pezzotti Giuseppe
Published: March 2009

Many of the properties of Si-based ceramics, including their structural behavior, are strongly influenced by their micro/nanostructure and by the microscopic residual stress fields piled up during processing and/or usage. The electron beam, used as a sharp and reliable probe for high-resolution cathodoluminescence (CL) assessments, can routinely provide a suitable tool for assessing both the structural and the mechanical characteristics of Si-based ceramics on a sub-micrometer scale. Although the full development of stress-related CL techniques is still in embryo, we show here the possibility of assessing microscopic stress fields inside a field-emission gun scanning electron microscope (FEG-SEM). This new assessment takes advantage of the piezo-spectroscopic effect on selected bands of CL spectra and it is applied here to both β-silicon nitride (Si3N4) and β-silicon carbide (SiC) ceramics. CL spectra in both materials arise from their peculiar optically active defects. Experimental assessments of microstress fields may open a completely new perspective in the development of high-performance Si-based ceramics because one can directly visualize how residual stresses distribute within the material micro/nanostructure and miniaturized devices.
SiC Oxidation Protective Coating for Graphite Mould
Authors: Kim Jae Won , Park Seong Hwan , Kim H.C. , Jung Yeon Gil , Lee Je Hyun , Paik Ung Yu
Published: March 2009

In order to exploit the anti-oxidation property of graphite mould, a new type of oxidation protective coating is produced by a pack cementation diffusion coating technique. To enable this material to be used at high temperatures, graphite moulds are coated with Si/SiC slips. The anionic dispersant is added to disperse the slip uniformly, of which the optimal amount is evaluated with viscosity. The graphite mold specimens are surface-modified at 100 °C for 10 minutes in a non-polar polymer aqua-solution, considering the uniform wettability of slip. The surface-modified graphite mold specimen shows better wettability than the nonsurface- modified graphite one when coating process is performed through the slip. The interface-reaction of the specimens is performed at 1450 °C in a reduction atmosphere. The microstructure and composition before and after the pack cementation are observed by SEM and EDS, and the phase identify was performed with XRD. The layer of specimens double-coated by the pack cementation and Si/SiC slip coating method is stable, and properties of SiC coating layer formed on the graphite mould surface are dependent on particle size of starting material, Si, and open-pore size of the graphite mould surface. It is found that larger particle size of Si and smaller open-pore size of the graphite mold were the preferable conditions for the interface produces an optimal reaction which anti-oxidation coating.
Mechanical Properties and Related Histological Alterations of Engineered Tendons In Vivo
Authors: Qin Ting Wu , Zhang Shujiang , Yang Zhi Ming , Mo Xiang Tao , Li Xiu Qun
Published: March 2009

The purpose of this research is to find out the interaction between histological alterations and mechanical properties of engineered tendon implanted in situ. Defects of 0.5cm-1.0cm were made at deep flexor tendons by surgical procedure. Engineered tendons using degradable scaffolds polyglytic acid (PGA) mesh and tendon cells were implanted to repair the defects. Chickens were killed respectively at 2 weeks, 4 weeks, 6 weeks, and 8 weeks after surgery. The implants were
taken out for histological examination, biomechanical test, and collagen synthesis assay. The results showed that after surgery the PGA scaffolds degraded fast and took precedence of collagen synthesis. There were not enough amount and maturation of the collagen fibers of the new tendon at 2-8 weeks after surgery. The biomechanical properties of new tendons were less than those of the normal tendon. Therefore, it is necessary to construct engineered tendons with better degradation
rate of scaffolds and suitable biomechanical stimulation so that more collagen synthesis and better biomechanical properties of new tendons can be developed early after implantation.
Preparation of DNA Hybrid Polyethersulfone Microspheres for Endocrine Disruptor Removal
Authors: Zhao Changsheng , Yang Kaiguang , Wen Xian , Li Fan , Zheng Xiangben , Nishi Norio
Published: March 2009

In this paper, DNA hybrid polyethersulfone (PES) microspheres, including DNA-loaded porous particles and DNA-encapsulated hollow particles, are fabricated using a liquid-liquid phase separation method based on precipitation technique; the microspheres are then used for the removal of poisonous organic chemicals and endocrine disruptors. With the increase of the DNA amount incorporated into the spheres, the removal ratios increased both for the poisonous organic chemicals
and endocrine disruptors. The particles without DNA also remove and accumulate poisonous organic chemicals due to the high porosity of the spheres. The results suggested that DNA hybrid PES particles could be prepared by a liquid-liquid phase separation method, and have potential to serve as a useful functional biomaterial for medical, engineering, and environmental application.
Confocal Study of Specific Targeting of Quantum Dot Nanocomposites to Cancer Cells
Authors: Zhang Yong , Zhang J.
Published: March 2009

Targeting of drugs and therapeutic materials to target cells or designated intracellular locations relies upon their cellular / sub-cellular targeting and trafficking. The ideal optical properties of quantum dots offer the possibility of using them as fluorescent probes to study the intracellular uptake and pathway of drugs or biomolecules. Quantum dots, ZnS coated CdSe, were synthesized and successfully incorporated into polystyrene (PS) particles grafted with carboxyl groups and folic acid was attached to the nanoparticle surfaces. The nanocomposites were monodisperse and highly luminescent, and their intracellular uptake to cancer cells was investigated using confocal microscopy.
Spherical Porous Microparticle of Hydroxyapatite/Polysaccharides Nanocomposites
Authors: Ikoma Toshiyuki , Azuma N. , Itoh Shigeru , Omi H. , Nishikawa S. , Toh Satoshi , Tanaka M.
Published: March 2009

Nanocomposites of hydroxyapatite / chondroitin sulfate or hyaluronic acid were prepared by a wet method through a self-organization. In the nanocomposites, the c-axis of hydroxyapatite nanocrystals was oriented along the longitudinal axis of the aggregations. The spherical porous microparticles by using a spray drying method were developed with the size range of 1.0 to 20 µm, specific surface area of c.a. 100 m2g-1 and porosities of over 60vol%. No thermal decomposition of polysaccharides was occurred through the spray drying processes. It is note worth that the zeta-potential of the microparticles were gradually changed to be negative value of -35mV against the content of polysaccharides. The animal experiments implanted under the skin showed that the HAp/ChS had a good biocompatibility for 4 week implantations. The spherical microparticles will be applicable to create more complicated composites and drug carriers.
Preparation of Bioactive Nanoparticles in the System CaO-P2O5-SiO2 Using Microemulsions
Authors: Zhao Na Ru , Wang Ying Jun , Chen Xiao Feng , Yang Yu Xia , Wei Kun , Wu Gang
Published: March 2009

The bioactive nanoparticles in the system CaO-P2O5-SiO2 were synthesized via
microemulsions method in this study. The structure and properties of the nanoparticles were investigated in details using XRD, TEM, FTIR, BET techniques. It was found that, in a stable phase W/O emulsions, the diameter of the nanoparticles were related to the molar ratio of water to surfactant (γ). Under the favorable conditions, i.e. γ=6, nano-sized spherical amorphous particles could be obtained with the average diameter of 25 nm. The microemulsions could be an alternative method to prepare bioactive nanoparticles for bone reparation and bone tissue engineering scaffolds.
In Vitro Degradation of Medical Polyacrylamide Hydrogel I.Oxidation
Authors: Wan Zi Yi , Xi Ting Fei , Zhao P. , Fan Cheng Xiang , Sun Y. , Feng Z.G.
Published: March 2009

Polyacrylamide (PAM) was usually atoxic, stable. Its hydrogel (PAMG) has been used in plastic and aesthetic surgery more than 10 years in P.R.China, Ukraine and Russia. But there were some complications with PAMG injected in patients. Considering the complicacy in vivo, it was necessary to study the PAMG’s stability. In this paper, H2O2 was added in PAMG in vitro and acrylamide (AM) content after oxidating was determined using HPLC method. Detection limit for AM can be achieved in the parts-per-billion rang. The AM content in supernatant at 0.5, 1,2 and 3 hr after oxidating of PAMG was 1.27e-8g/ml, 1.35e-8g/ml, 1.03e-7g/ml and 2.74e-7g/ml, respectively. The AM content in supernatant of PAMG was 7.70e-9g/ml. These results indicated that PAMG can be degraded to AM by hydroxyl radical. Under the same condition, the AM content was stable. So, AM can exist for a while when it was produce by degrading of PAMG. That can increase the toxicity of PAMG.
Biomimetic Amphiphiles for Polymeric Micellar Carrier System
Authors: Xu Jian Ping , Ji Jian , Chen Wei-Dong , Shen Jia Cong
Published: March 2009

A commercial available amphiphilic polymer, Cholesterol terminated PEO (Chol-PEO), was used as novel biomimetic drug delivery system. The association behavior of Chol-PEOs in aqueous solution was studied by fluorescence probe technique and transmission electron microscope (TEM). Fluorescence excitation spectra for pyrene probe solubilized in the aggregates of Chol-PEOs suggested the presence of a critical micelle concentration (cmc) in water. TEM images of the aggregates suggested that the PEO block formed the biocompatible micelle coronas and the cholesterol block formed the hydrophobic micelle cores. These new biomimetic diblock copolymers were evaluated as nanocapsules for the delivery of hydrophobic drugs and drug release behavior of a hydrophobic anti-cancer drug, adriamycin (ADR), was examined.
Computer-Assisted Image Processing Techniques for Quantitative Analysis of Cell Migrations on Collagen-Coated Glass
Authors: Park B.J. , Kim Seok Cheol , Lee D.H. , Son Hyun Joo , Nam K.C. , Takatori K. , Aihara M. , Park Jong Chul
Published: March 2009

In this study, a computer-assisted cell tracking system including an automatic image processing program for rapid and precise analysis of cell migration in various conditions was self-designed and L-929 cell migration on the glass coated with type I collagen was examined using this cell tracking system. Furthermore, computer-based image processing software, with the capture program to choose the capture interval and period, and analysis techniques were developed for quantitative analysis of the cell migration on extracellular matrices. The results showed that the migration speed of L-929 cells on the collagen-coated glass was significantly (p < 0.05) increased compared to the non-coated control. On the morphological observations, it was showed that the cells on the collagen-coated glass looked much healthier than those on the control. These results suggested that this cell tracking system would provide tools for the analysis of cell migration in various in vitro conditions and might be effective enough to evaluate various biological events including embryonic development as well as physiological and pathological tissue reorganization.
Single Crystal Growth and Structure Analysis of AB-Type Carbonate Apatite
Authors: Suetsugu Yasushi , Ikoma Toshiyuki , Kikuchi Masanori , Tanaka M.
Published: March 2009

Single crystals of AB-type carbonate apatite were grown by a CaCO3-Na2CO3 flux
method under high pressure of Ar gas. The crystals obtained were hexagonal prismatic elongated along the c-axis with the length of 2mm and the diameter of 0.3mm at a maximum. Chemical formula was Ca8.8Na1.2[(PO4)4.8(CO3)1.2]CO3 and the space group was hexagonal P6 with cell parameters a = 0.9379(2)nm, c = 0.6935(1)nm. The detailed crystal structure determined with a reliability factor Rw = 0.047 indicated that the triangular plane of carbonate ion occupying B-site was slanted off the crystallographic mirror plane and the angle of the carbonate triangle with the mirror plane varied depending on Na-substitution of adjacent Ca sites whilst the A-site carbonate ion was parallel to the c-axis.
Fabrication of Apatite Monolith from Calcium Sulphate
Authors: Kunio Ishikawa , Matsuya Shigeki , Suzuki Yumiko , Udoh Koh-ichi , Nakagawa Masaharu , Koyano Kiyoshi
Published: March 2009

Present study evaluated the feasibility of apatite monolith preparation from calcium
sulfate monolith using ammonium phosphate solution. We found that calcium phosphate monolith transforms to apatitic monolith without changing its original morphology when a proper temperature and a proper phosphate solution was selected. Prepared apatite was B-type carbonate apatite with low crystallinity. Although mechanical strength of the apatite monolith was lower than original calcium sulphate monolith, we concluded present method may be useful for the fabrication
of apatite monolith since we can prepare different shape of apatite monoliths based on the setting reaction of calcium sulphate and compositional transformation to apatitic mineral.
Novel Techniques of Titanium Surface Patterning
Authors: Lu Xiong , Leng Yang , Jiang Limin , Tian Zhaowu
Published: March 2009

Surface microscopic patterns can enhance osteointegration of titanium implants in
orthopedic and dental applications. It is a challenge to produce regular topographic patterns on titanium. We have developed two techniques, jet-electrochemical micromachining (Jet-EMM) and the confined etchant technique (CELT) to produce topographic patterns on titanium. The results demonstrate that Jet-EMM has the ability to produce micro-hole arrays on either flat or curved surfaces and CELT can fabricate complex micro patterns with limited depth on a flat surface.
Experimental Study of Partially Demineralized Bone Matrix as Bone Tissue Engineering Scaffold
Authors: Cui Lei , Li Dong , Liu Xiang Dong , Chen Fanfan , Liu Wei , Cao Yi Lin
Published: March 2009

Objective The purpose of this study is to explore the growth, differentiation and
osteogeneration of bone marrow stromal cells (BMSCs) on partially demineralized bone matrix (pDBM) and to generate bone tissue by tissue engineering approach in vivo. Methods Demineralized bone was processed from femur head of Shanghai white swine. Calcium content, porosity and pore size was measured respectively. In vitro osteogenic differentiated human BMSCs of passage 3 were seeded in pDBM. Adhesive rate of cells to pDBM was calculated 24hours after seeding. Distribution, growth and proliferation of BMSCs on pDBM were observed with fluorescent
DiI labeling. Matrix disposition was analyzed with SEM observation. Cell-material complex was implanted subcutaneously in nude mice. The implants were harvested at 8, 12 weeks post surgery and samples were observed by H&E staining. Results BMSCs adhered well on the material and the distribution of cells was uniform. The adhesive rate is 99.1%±1%. New bone formation was observed in implant of 8, 12 weeks respectively. The newly formed bone was generated on the surface of the residual material and a layer of cells with typical characteristic of osteoblast was
observed to adhere on the surface of the new bone. Conclusion With good biocompatibility to hBMSCs, pDBM could serve as ideal scaffold for bone tissue engineering both in vitro and in vivo.
Tissue Engineered Bone Formation with Polymer/Ceramic Composites by Press-and-Baking Method
Authors: Jung Young Mee , Kim Soo Hyun , Kim Sang Soo , You Hee Jin , Kim Byoung Soo , Kim Suk Young , Kim Sang Heon , Kim Young Ha
Published: March 2009

A novel process was developed to fabricate polymer/ceramic composites for bone
tissue engineering. The mixture of polylactic acid (PLA), calcium metaphosphate (CMP), and NaCl were compressed and subsequently heated. After dissolving the NaCl salts, porous biodegradable polymer/ceramic composite scaffolds were formed. The characteristics of the scaffolds were compared to those of scaffolds fabricated using a conventional solvent casting method, in terms of pore structure, pore size distribution, and mechanical properties. The scaffolds were seeded by
osteoblasts and cultured in vitro or implanted into nude mice subcutaneously for up to 5 weeks. Cells were better grown to form tissue-like structures on CMP/PLA composites fabricated by the Press-and-Baking method. In addition, the alkaline phosphatase activity of and calcium deposition in the scaffolds explanted from mice were enhanced significantly for the scaffolds by Press-and-Baking compared to them by solvent casting. Taken together, these results suggest that CMP promote cell differentiation and proliferation via direct interaction with cells in the CMP/PLA
composites. This novel PLA/CMP composite will be applicable for bone tissue engineering to support and cell differentiation and growth.
Fracture Toughness Enhancements through Stress Shielding in Functionally Graded SiC-TiC Composites
Authors: Liversage John H. , McLachlan David S. , Herrmann Mathias
Published: March 2009

It is often the case that the low fracture toughness of polycrystalline ceramics limit the load-bearing capabilities of components made from such materials. In an effort to improve the fracture toughness of a SiC-TiC composite material, a novel stress-shielding approach was adopted so as to reduce the effective mode I stress intensity around a crack tip within the composite body. To this end, a series of functionally graded materials were produced, with samples having a preselected
spatial SiC-TiC composition variation. The spatial composition variation within each
sample was set up according to one of several exponential mathematical functions. In this way the resultant spatial variation in thermal expansion coefficients was also controlled through the thickness of the material, and a particular stress and strain distribution could be tailored within the body. Samples with tailored near-surface compressive stress states showed a significant improvement in c KI , as measured by means of a flexure test, in comparison with stress-free samples of a homogeneous composition corresponding to the composition found at the test-point
within the gradient materials.
Fracture of Monoliths Fabricated by Stacking Water Processed Green Ceramic Tapes
Authors: Gurauskis Jonas , Pascual Javier , Lube Tanja , Sanchez-Herencia Antonio Javier , Baudín Carmen
Published: March 2009

A lamination technique for joining ceramic green tapes fabricated from aqueous ceramic slurries via tape casting process is investigated. Monolithic pieces with varying compositions within the Al2O3 / t-ZrO2 system were fabricated by gluing the constituent tapes and pressing at room temperature. The quality of the interfaces between the different tapes in sintered specimens was evaluated by means of the fracture behavior of the pieces during the ball on three balls test. Different fracture patterns were found as a function of pressure and the characteristics of the tapes. Large scale interface defects led to delamination during fracture whereas no critical defects could be observed in the smooth fracture surfaces. Small scale interface defects were revealed by fracture.
Structure of Post-Creep Carbon Fibres
Authors: Rennhofer H. , Loidl Dieter , Brandstetter Johann , Kromp Karl , Weiss Roland , Peterlik Herwig
Published: March 2009

Creep tests have been performed for carbon fibre bundles (Toray, HTA5131) in a temperature range from 1500 °C to 1800 °C and at various stress levels in a tensile testing machine in vacuum (pressure was kept below 10-3 mbar). Creep parameters have been obtained from the diagrams elongation versus time. X-rays (SAXS and WAXD) have been used for accompanying structural investigations. An increase in the alignment of the graphene sheets with respect to the fibre (and thus the loading) axis was observed with increasing test temperature. For fibres stabilised by heat treatment (2 hours, 2100 °C, without load) no creep and no structural change could be observed.
Fractographic Studies of Sapphire Fibers Using Laser Scanning Confocal Microscopy
Authors: López-Cepero José M. , Quispe Cancapa J.J. , de Arellano-López António Ramirez , Martínez-Fernández Julian
Published: March 2009

Laser scanning confocal microscopy (LSCM) is a microscopic technique which allows for height discrimination. The ability to gather 3D data, along with adequate resolution (around 400 nm), makes the technique suitable for fractography; however, its applications in this area are not sufficiently explored. In this work, LSCM and SEM are applied to the study of fracture surfaces in sapphire and ruby fibers submitted to tensile stress in high-temperature conditions. The obtained qualitative and quantitative information demonstrates the validity of LSCM as a fractographical technique, allowing for clear identification of fractographical features and providing novel insight in the phenomenon of subcritical crack growth (SCG).
Fracture Behaviour of Pressureless Sintered Nickel-Reinforced Alumina Composites
Authors: Beverina Alessio , Sanchez-Herencia Antonio Javier , Hernández N. , Moreno Rodrigo
Published: March 2009

Nickel-reinforced alumina composites have been manufactured by aqueous slip casting and pressureless sintered under flowing atmosphere of argon with 0,36 and 1% of oxygen in order to force interfacial reactions leading to the formation of a nickel-aluminum spinel. Colloidal stability of concentrated suspensions of alumina with 5, 10 and 15 vol% of nickel has been studied in terms of zeta potential, rheometry and packing density. The processed composites show a high dispersion of the nickel into the alumina matrix and green densities of 60-70 %th. The effect of
sintering temperature and atmosphere on the mechanical behaviour of the composites has been investigated through Vickers indentation and fractographic SEM observations.
Experimental Research on ELID Grinding and Cutting Performance of Nano Cemented Carbide Cutters
Authors: Zhang Fei Hu , Gui J.C. , Liu Yi Zhi , Zhang Hua Li
Published: March 2009

Nano cemented carbide is a new style cutter material. Because its grain size is very small, it is superior to common cemented carbide in properties, such as high hardness, fracture toughness, flexural strength and higher abrasion resistance. As a cutter material, nano cemented carbide has wide use. In this paper, nano cemented carbide tool was ground with ELID technology, and the cutting properties of nano cemented carbide were studied, and the difference in cutting properties
among the ultra-fine grain, common cemented carbide and nano cemented carbide was analyzed under the same condition. Results imply that the ground surface roughness of nano cemented carbide is obviously lower than that of common cemented carbide, and the tool life of nano cemented carbide is 5-7 times longer than that of common cemented carbide at low cutting speed.
ELID Grinding Properties of High-Strength Reaction-Sintered SiC
Authors: Dai Y. , Ohmori Hitoshi , Lin Wei Min , Eto H. , Ebizuka N. , Tsuno K.
Published: March 2009

The high-strength reaction-sintered silicon carbide (RS-SiC) developed by TOSHIBA is one of the most excellent materials for large-scale space-borne optics. The bending strength of the high-strength RS-SiC is two times higher than other SiC ceramics. The purpose of this study is to investigate the ELID grinding properties of the high strength RS-SiC. Two types of metal bond diamond wheels (cup type and straight type) were used to grinding tests. The ground surface properties, such as roughness, subsurface damage and micro-step were made clear by measurement or
observation. It was confirmed that, both the surface roughness and the depth of micro-step produced by cup-wheel were lower than those produced by straight-wheel. When a #20000 grit sized cup-wheel was used, a considerably high quality mirror surface (Ra<0.8nm) can be achived.
Investigation on the Dressing Shape of Vacuum Chuck in Wafer Rotation Grinding
Authors: Gao Hang , Tian Y.B. , Jia Zhen Yuan , Kang Ren Ke
Published: March 2009

During wafer rotation grinding, the wafer is centered on a porous ceramic vacuum chuck and so; the dressing shape of vacuum chuck becomes a critical factor affecting the flatness of ground wafers. In this paper, a theoretical model of the dressing shape of vacuum chuck in wafer rotation grinding is developed. From the model, the relationship between the dressing shape and the affecting factors is given. The dressing shape is predicted by computer simulations based on theoretic model and the vacuum chuck dressing experiments are conducted to verify the theoretical model. It is shown that the theoretical analysis matches the experimental measuring results very well. The study results provide a theoretical basis for analysis of the relationship between the dressing shape and the flatness of ground wafer, for improving the flatness of ground wafer and for selecting the proper parameters of grinding process.
Technique of Comparison and Optimization of Conditions for Magnetic Abrasive Finishing
Authors: Baron Yuri M. , Ko S.L. , Park Jung Il
Published: March 2009

In this paper, the new technique involving comparison and optimization of
conditions for Magnetic Abrasive Finishing (MAF) is suggested, taking into account the basic laws stated for process MAF. The formulas for the calculation of the criteria for optimization are created when the process MAF is used for polishing, removal of burrs, and other purposes. The application of the technique is shown in an experiment on the optimization conditions for the removal of burrs after drilling using the MAF method. The technique can be used after standards for this process are developed.
Finishing of Shape Surfaces by Magnetic Abrasive Polishing Method with Rotating Working Area
Authors: Litvinenko V.A.
Published: March 2009

The stable industrial trends towards improvement of product accuracy and quality call for necessity to widen the nomenclature of details surfaces and materials, which need finishing. The method of magnetic abrasive finishing (MAF) helps to meet these challenges. This paper presents the results of study of technological potential of MAF equipment with rotating working area, filled with magnetic-abrasive powder. Such equipment allows to polish the cylindrical, conical and helical surfaces of core details made of magnetic and non-magnetic materials. Geometrical accuracy and
roughness of the above mentioned surfaces after MAF and also the conditions of their performance theoretically and experimentally studied. It is established that MAF changes the fine structure of detail surface layer made of hardened high-speed steels, titanium and aluminum alloys and improves their surface performance.
Enhancing the AWJ Cutting Performance by Multipass Machining with Controlled Nozzle Oscillation
Authors: Wang Jun , Xu S.
Published: March 2009

The cutting performance in abrasive waterjet (AWJ) multipass cutting with and without controlled nozzle oscillation is presented based on an experimental investigation cutting an 87% alumina ceramic. The cutting capacity in terms of the depth of cut and the kerf geometrical features is analyzed with respect to the process variables. It is found that multipass cutting is a viable means to increase the cutting performance and application domain of this technology, while a further increase in the cutting performance can be made by using a controlled nozzle oscillation technique.
Study on the Machined Surface Topography and Performances on Electrochemical Finishing
Authors: Li H.Y. , Liu Xiao Mei , Liu H.J. , Fang Jian Cheng
Published: March 2009

In this paper, electrochemical finishing（ECF） is presented. Compared with conventional finishing technology, the characterization of surface topography machined by ECF and its effect on the performance, including friction coefficient, original wear and tear, precision durability, fatigue strength, contact stiffness, corrosion resistance and adhesiveness are analyzed and studied. Experimental results have testified that ECF can observably improve surface quality of parts and
finally improve its physical mechanical performances and lifetime to a large extent.
Numerical Simulation of the Cooling Process of Extruded Plastic Profiles within Vacuum Calibrators
Authors: Zhao D.Y. , Wang Min Jie , Song M.C.
Published: March 2009

Plastic profiles produced by extrusion die are cooled down and calibrated by calibrators, so it is an important basis to solve design problems of calibrators that how to obtain the transient temperature field of cooling process of hot plastic profiles. Based on the analysis of heat transfer ways during the cooling process, computation model, initial and boundary conditions are studied deeply, and then ANSYS is applied to simulate the cooling process of plastic profiles. Lastly, the transient temperature field of the cooling process is gain. Results of the numerical simulation show that the temperature drops of functional blocks, main-walls and inner-ribs are reduced in order of priority. Based on the results, the cooling water channels can be adjusted in order to improve the distributing uniformity of temperature field. All this is effective to the calibrators’ design.
Deformation Analysis of Fixturing for Workpiece with Complex Geometry
Authors: Wang Yan , Chen Xun , Gindy Nabil
Published: March 2009

Finite element (FE) analysis is very useful in the early stage of a fixture development in order to reduce or eliminate design problems. Accurate prediction of fixture-workpiece deformation requires an appropriate representation of the contact relationship between fixture elements and workpieces. The paper addresses the special features of the deformation analysis between complicatedly shaped components and fixture elements. The effectiveness and the scope of applicability of commonly used methods are analysed. The verified FE analysis is used to predict
surface error arising from deformations, and to evaluate the deformation distributions from fixture elements and workpiece. Based on the FE analysis, the tolerance can be allocated to the fixture elements and the workpiece. The development of a turbine blade fixture is provided as case study.
Faults Monitoring and Diagnosis of Ball Bearing Based on Hilbert-Huang Transformation
Authors: Li H. , Zheng H.Q. , Tang L.W.
Published: March 2009

A novel scheme for ball bearing faults detection is presented based on Hilbert-Huang
transformation and its energy spectrum. The basic method is introduced in detail. The energy spectrum is applied in the research of the faults diagnosis for the ball bearing of machine tool. Firstly, the analyzed vibration signals are separated into a series of intrinsic mode function using the empirical mode decomposition. Then, the energy spectrum is applied to the intrinsic mode function. The experimental results show that this method based on Hilbert-Huang transformation and energy spectrum can effectively diagnosis the faults of the ball bearing.
Extracting Gear Fault Features Using Maximal Bispectrum
Authors: Zhang Gui Cai , Chen Jin , Li Fu Cai , Li Wei Hua
Published: March 2009

Bispectrum is a powerful tool for non-Gaussian signal processing and nonlinearity detection. However, it is difficult to use in practical applications due to that it is a 2-dimensional function. Bispectral slices are widely used reduction methods, and they can only represent a small part of the whole bispectral information. Integrated bispectrum contains more signal features than that of the bispectral slices, whereas the integration will lose the focus of some signal features. To overcome these problems, a new approach called maximal bispectrum is proposed to extract signal features. Maximal bispectrum is obtained by selecting the maximal values of every row of the magnitude bispectrum in the whole bispectral plane and it is a 1-dimensional function. Feature extraction based on maximal bispectrum is investigated and the maximal bispectrum is used to extract features of gear fault. Experimental results indicate that the maximal bispectrum is effective for diagnosing gear crack fault.
Fatigue Damage Evaluation of Organic Coatings Subjected to Mechanical Stress
Authors: Darowicki Kazimierz , Szociński M.
Published: March 2009

A number of structures fail due to the fatigue damage resulting from cyclic mechanical stress. However, as far as coatings are concerned this degradation factor remains underestimated. In the paper the authors compare an impact of repetitive mechanical stress on as-received epoxy coating and on the UV and elevated temperature pre-exposed epoxy film.
Genetic Algorithms Based Rubbing Location Identification in a Rotor System
Authors: Lu Wen Xiu , Chu Fu Lei , Guo Dan
Published: March 2009

The rubbing fault is a very serious and frequent malfunction in rotating machinery, and the determination of the rubbing location is very important in actual fault diagnosis. In this paper, a method based on genetic algorithms to detect the rubbing location is presented. The finite element model of the rubbing rotor is established with the rubbing location, the stator stiffness, the clearance between stator and rotor, the damping coefficient and the friction coefficient as the fault parameters, and the rubbing location determination is transferred into the parameter identification problem. The genetic algorithm is then utilized to search the solution. Using genetic algorithms avoids some of the weaknesses of traditional parameter identification methods such as local minimum problem in nonlinear system identification. The experimental results suggest that the rubbing location can be effectively determined when the rubbing occurs.
Ultrasonic/Guided Waves for Structural Health Monitoring
Authors: Staszewski W.J.
Published: March 2009

Structural damage detection and monitoring is one of the major maintenance activities in transportation, processing and civil engineering. Current procedures are based on scheduled inspections which are often time/labour consuming and expensive. Guided ultrasonic waves offer the ability of inspecting large structures with a small number of transducers. Recent developments in smart sensor technologies allow for integration of these transducers with monitored structures. This is associated with a new design philosophy leading to more efficient and economically attractive structures. The paper briefly discusses various damage detection methods based on structural, ultrasonic and guided ultrasonic waves. The focus is on recent research advances in damage monitoring techniques, smart sensor technologies and signal processing.
Damage Detection in Circular Cylindrical Shells by Frequency Sensitivities and Mode Shapes
Authors: Wang Zhi Hua , Chen Jianyun , Zhao Yonggang , Ma Hong Wei
Published: March 2009

In the present paper, the Damage Location Assurance Criterion (DLAC) is extended to locate and assess damage in a circular cylindrical shell based on natural frequencies and mode shapes. Frequency sensitivities computed from a defect-free finite element model are applied to calculate the theoretical frequency changes. The axial position of the damage can be easily obtained by comparing the theoretical and measured frequency changes due to damage. For the shell is axisymmetric, additional information of mode shapes is introduced to locate the exact damage position. The damage extent can be estimated by the first order approximation method. The feasibility and practicality of the damage detection scheme are evaluated for several damage scenarios by locating and sizing damage in the free–free, simply-supported and free-clamped shells, respectively. Results from simulation examples show that the proposed detection scheme can confidently locate the single or multiple positions of damage. It is also observed that damage extent can be estimated with a relatively small error.
Prediction of Machines Health with Application of an Intelligent Approach – a Mining Machinery Case Study
Authors: Gibiec Mariusz
Published: March 2009

Machine field services depend on sensor-driven management systems that provide alerts, alarms and indicators. At the moment the alarm is sounded, it’s sometimes too late to prevent the failure. There is no alert provided that looks at degradation over time. If we could monitor degradation, then we would forecast upcoming situations, and perform maintenance tasks when necessary. In our research we chose to focus on intelligent maintenance system, which is defined as the prediction and forecast of equipment performance.
Predictive maintenance, on the other hand, focuses on machine performance features. Data come from two sources: sensors mounted on the machine to gather the machine feature information, and information from the entire manufacturing system, including machine productivity, past history and trending. By correlating data from these sources — current and historical — predictions can be made about future performance.
In this article case study of coal mining machinery health prediction is presented. Health of water pumping unit was considered. Such units placed in old mine shafts are crucial to avoid flooding working ones. As an effect of predictive maintenance it can be possible to improve safety and reduce costs incurred from accidents.
Impact Force Spectrum for Damage Assessment of Earthquake-Induced Structural Pounding
Authors: Jankowski Robert
Published: March 2009

Past earthquakes indicate that pounding between inadequately separated structures may cause considerable damage or even lead to collapse of colliding structures. Intensive study has been recently carried out on mitigation of pounding hazards. The assessment of damage due to structural pounding, or its prediction under a particular ground motion, requires the knowledge of the maximum impact force value expected during the time of earthquake. The aim of the present paper is to consider the concept of impact force response spectrum for two closely-spaced structures, which shows the plot of the peak value of pounding force as a function of the natural structural vibration period. The spectrum can be used as a practical tool to assess the magnitude of the expected pounding-induced damage and, if necessary, to apply some damage reduction techniques. In the analysis, both interacting structures have been modelled by single-degree-of-freedom systems and pounding has been simulated by the non-linear viscoelastic model, which accounts for the energy dissipation during impact. The examples of response spectra show that the appropriate selection of the separation gap between structures as well as the dynamic structural parameters, such as the natural vibration period, mass and damping, might have a significant influence on the intensity of damage due to earthquake-induced pounding.
A Comparative Study of the Current 3D Motif Combination Methods
Authors: Guo Jun , Gao Y. , Xie T.
Published: March 2009

As a special surface texture evaluation method, motif has received much attention since it was adopted as an ISO standard which is ISO12085 1996. However, like many other evaluation methods, it is based on 2 dimensional lines. The surface itself is three dimensional in nature. 3D motif evaluation should be more suitable. Until now, no 3D motif evaluation method has yet been proposed. A key issue is 3D motif combination to determine how the evaluation should be implemented. Three types of 3D MOTIF combination methods currently used are examined. Features such as algorithm complexity and application range are investigated. We conclude that the best 3D Motif combination method is not currently available. We should select a combination method based on the need for surface function analysis. Hybrid methods are also recommended.
Design, CFD Investigation and Implementation of a Novel Diverter Mechanism for Water Flow Measurement
Authors: Ho Y.L. , Chen Jian Yuan , Shaw Jiunn Haur , Yang C.T.
Published: March 2009

Fluid flow diverter serves as an essential element in high accuracy liquid flow calibration facility using a static weighing gravimetric system coupled with a flying-start-and-finish mechanism. For such flow system, stability and patterns of flow that passing through the draining nozzle and diverting module influence the accuracy of flow rate measurement. Consequently, the design and implementation of a diverter mechanism with feeding pipe section contribute dearly to the total measurement uncertainty of a standard calibration facility. In this research, a draining nozzle that changes from circular cross section to rectangular was specially developed to provide fluent flow transition. To facilitate the design process, the computational fluid dynamics (CFD) was introduced that effectively reduced the time consumption for prototype construction and test. The selected design exhibited symmetric and stable flow patterns in the desired operational flow range.
A Rapid Calibration Method for the Laser Scanning 3D Measurement System
Authors: Xu Z. , Tao L. , Sun Chang Ku , Zheng Y.
Published: March 2009

A rapid calibration method for the parameters of a laser light plane scanning 3D measurement system is proposed. The mathematic model and the calibrated parameters of the measurement system are presented. A novel orthogonal calibration jig composed of two orthogonal planes is designed. The CCD camera parameters and the light plane parameters of the measurement system can be rapidly calibrated with the orthogonal calibration jig. The laser scanning 3D measurement system is calibrated with the calibration jig. A standard plane is measured at different positions. The accuracy is better than 0.1mm.
Error Evaluation of Aspheric Surfaces and Calibration of the Test Instrument
Authors: Hao Qun , Zhu Q.D. , Wang Y.T.
Published: March 2009

As aspheric surfaces are more often used in optical systems, suitable error evaluation methods and suitable accuracy calibration methods for related test instruments are urgently required. The two unsolved but important issues are addressed. For evaluation of aspheric surfaces, a scheme is proposed to separate the surface errors into radius error and local error. The effects of the two errors on image quality are discussed. For test instrument calibration, a practical method using a defocused spherical surface is described and verified with an absolute testing instrument based on laser deflectometry, which was developed at Beijing Institute of Technology. The feasibility of the schemes is shown and experimental results are presented.
Characterisation of Surface Properties by a Multi-Function TPM
Authors: Liu Xian Ping , Zhang J.
Published: March 2009

A novel measurement system, the multi-functional Tribological Probe Microscope (TPM), has been developed to provide multi-function measurements of surface and surface properties. These properties are topography, friction, Young’s modulus, and nano-hardness. They are measured, point-by-point, in a single scan set up. The four function maps of surface topography, friction, hardness and Young’s modulus are correlated in space and time. In this paper we will brief the TPM system and demonstrate the capability of the multi-function evaluation of engineering surfaces and their correlated nature between these functions. It is believed that such direct correlated measurements will help scientist and engineers to understand surface and surface related properties and eventually to design and optimise a surface for a better performance.
Mechanical Behavior of Shape Memory Alloy Composites
Authors: Yang Sung Yong , Goo Byeong Choon , Kim Hyung Jin
Published: March 2009

Mechanical behavior of CFRP (Carbon Fiber Reinforced Polymer) containing Ni-Ti shape memory alloy (SMA) is investigated by experimental methods. Tensile and bending fracture tests were conducted to examine the strength of the composite for various volume fractions of the SMA. Charpy impact test was used to study the toughness of the SMA/CFRP hybrid composite. Finite element analysis was carried out for interface failure in bending test.
The Bond Strength and Fracture Behaviors of Hydroxyapatite Coatings on Carbon/Carbon Composites
Authors: Ling Siu Jin , Li Mu Sen , Peng Lu Yu
Published: March 2009

The effect of the density of carbon/ carbon composites (C/C composites) and presandblasted treatment technology on the bond strength between hydroxyapatite (HA) coatings and C/C composites had been studied. The microstructure and fracture surfaces had been examined by scanning electron microscopy (SEM). The shear strength of the HA coatings-C/C substrates was detected on a RGD-5 electric tension machine. Observations of fracture surfaces showed that carbon
fiber bundles could bond well with HA coatings under the power of 40 kW. Results indicated that a HA coating onto C/C composite substrates was a new promising biomaterial for replacing loaded human bones.
Analysis to Stress Relaxation Phenomena of Viscoelastic Materials by Means of Irreversible Thermodynamics (Ⅰ)
Authors: Dai Guang Ze , Yu Lanying , Ke Jian , Ni Qing Qing
Published: March 2009

Through defining a piece of viscoelastic medium as a thermodynamic system described by the generalized coordinates in the stress relaxation process, the evolution equation is derived by making use of the 1st law of thermodynamics, the 2nd law of thermodynamics and the Onsager’s principle. Based on the general solutions of the evolution, the constitutive expressions of uniaxial stress relaxation are obtained for both ideal viscoelastic solid materials and ideal viscoelastic fluid one respectively, in terms of the situation whether the coordinates participating in the entropy production are in stable or neutrally stable equilibrium state. As the result, whether the stress relaxes to a constant or zero depends on whether the free energy in viscoelastic medium is left or not.
Fabrication of Microstrip Band Pass Filters in GHz Region by Aerosol Deposition Process
Authors: Momotani Mihoko , Mori Naoko , Nam Song Min , Kakemoto Hirofumi , Wada Satoshi , Tsurumi Takaaki , Akedo Jun
Published: March 2009

In order to fabricate a microstrip band pass filter in GHz region as a passive component of RF modules, Al2O3 thick films were prepared on Cu metal substrates by AD (Aerosol Deposition) process. The dimensions of the filters were determined by the high frequency electromagnetic analysis. The filters were successfully fabricated on AD-derived Al2O3 thick films by employing sputtering, photolithography, electroplating and chemical etching processes. Their filtering characteristics were examined by a Network Analyzer. Through this work, we suggest that the AD process will be important the fabrication technology for integrated RF modules.