bluuebunny/crossref_metadata_2025 huggingface dataset:
A Try for Improvement of Performance in Dry Barrel Finishing by Centrifugal Disc Type
Authors: Kitajima Koichi , Yamamoto Akihiro , Izawa Moriyasu
Published: March 2009

The speed-up of the disc rotation in dry centrifugal barrel finishing is done and its
influence on finishing characteristics is experimentally examined. The workpiece is a sliced
cold rolled bar of plain carbon steel (S45C in JIS, HB221). It is 32mm in diameter and
finished to10mm in thickness by belt grinding. The equilateral triangular prism nylon media
(1010mm, A#320) is used at 20vol% in media charging ratio. The disc rotation speed is
increased up to 500min-1. By speeding up the disc rotation, the finishing speed improves, but
the total efficiency decreases.
Study on Anodic Smoothening Velocity in Electrochemical Abrasive Lapping
Authors: Pang Gui Bing , Xu Wen Ji , Wang Xu Yue , Xie A.D.Y. , Li H.Y. , Wang H.
Published: March 2009

By analysing the change of the anodic surface topography in Electrochemical Abrasive
Lapping (ECAL), the influence of the lapping action and the electrochemical action on the anodic
smoothening velocity is studied. In electrochemical finishing, the micro-peaks on the anodic surface
could be smoothened quickly by electrochemical action and the surface topography presents the
profile wave, but in ECAL, the profile wave after electrochemical action could be divided into
micro-peaks renewedly by lapping action and the alternation of electrochemical action and lapping
action makes the surface topography before electrochemical action present profile micro-peaks,
which will increase the anodic smoothening velocity. The influence of machining parameters, such as
abrasive grain sizes, tool’s pressure, abrasive content, frictional velocity and current density etc, on
the anodic smoothening velocity is discussed in detailed.
Cost Optimization of Abrasive Blasting Systems: A New and Effective Way for Using Blasting Nozzles
Authors: Pi Vu Ngoc , Hoogstrate A.M.
Published: March 2009

This paper introduces a new and comprehensive study on cost optimization of abrasive blasting systems. In the study, the effects of many parameters such as nozzle diameter, air pressure, efficiency, cost components as well as the effect of the nozzle wear on the cleaning cost were investigated. A new model for calculation of the optimal exchanged nozzle diameter (called “optimal diameter”) was proposed. With “optimal diameter” a new and effective way of using and making blasting nozzles was proposed and both the cleaning cost and the cleaning time can be reduced significantly.
Microstructural Analysis for Si Wafer after CMG Process
Authors: Kamiya Sumio , Iwase Hisao , Nagaike Tetsuya , Zhou Li Bo , Eda Hiroshi , Kimura Shun-ichiro
Published: March 2009

The single crystal of Si is still one of the most important candidates among other materials
including Single crystals of SiC, GaN, C(diamond) or compound semiconductors. The innovative
process as called CMG(Chemo-Mechanical-Grinding) for Si wafer has been recently developed
which is different from conventional CMP(Chemo-Mechanical-Polishing ) process. The CMG
process can be done under dry conditions using CeO2 based solid bulk abrasives. The microstructures
for surface and subsurface of Si single crystal after CMG process were analyzed using TEM/EDX,
AFM, MFP-3D Microscope. The mechanism of CMG process was also investigated by X-ray
diffraction and ICP chemical analysis using products by chemical reaction between Si and CeO2
abrasives. The results showed that Si single crystal after CMG had, 1) no defects even Si lattice revel
or mechanical imperfections,2) better surface roughness as compared to CMP process. The CMG
mechanism concluded that CeO2 reacted with Si producing Ce-Si-O amorphous phase.
Study on Structure Transformation of Si Wafer in Grinding Process
Authors: Zhou Li Bo , Yamaguchi Makoto , Shimizu Jun , Eda Hiroshi
Published: March 2009

In this paper, the surface and subsurface of silicon wafers ground by different wheels have
been studied. In the conventional grinding with diamond wheels, it is shown from the top that the
subsurface of wafer consists of amorphous Si, followed by a thin damaged layer, strained crystal with
a large compressive residue stress, and then the bulk material in single crystal. In a severe condition
which causes grinding burn, part of amorphous Si is re-crystallized to form a poly-crystal Si, and part
of amorphous Si possibly reacts with oxygen to form SiO2. This phenomenon becomes more
pronounced in the backgrinding process with a fine grit diamond wheel when the conditions are
improperly selected. In order to obtain a defect-free crystal Si structure in grinding, authors have
proposed a new chemo-mechanical grinding (CMG) process which enables to remove Si from wafer
but with no structure transformation induced to its surface.
The Effect of Workpiece Roundness of the Run-Out of CBN Electroplated Grinding Wheels
Authors: Pearce T.R.A. , Fricker D.C. , Speight A.
Published: March 2009

Electroplated CBN grinding wheels are not normally trued on a grinding machine and therefore inherently have a degree of run-out. The effect of run-out on workpiece roundness has both been modelled and measured experimentally. As well as affecting roundness, run-out can result in intermittent grinding around the wheel periphery, which can then lead to preferential wear on the most eccentric part of the wheel. This intermittent effect has been investigated by modelling the variation of the normal grinding force around the wheel and by measuring the variation of acoustic emission around the wheel during grinding tests.
Preparation of Turbulated Cooling Hole for Gas Turbine Blade Using Electrochemical Machining
Authors: Wang M. , Zhu Di , Qu Ning Song , Zhang C.Y.
Published: March 2009

With the development of high performance of gas turbine engine, there is a tendency to
design the ribs in the cooling hole in order to improve the heat transfer and cooling efficiency in a
cooling passage. This paper focuses on a machining method of the burbulated cooling hole. The
cooling hole is formed by electrochemical machining (ECM) process using a shaped electrode. The
ribs on the hole wall form using ECM after the shaped electrode is lowed into the bottom of the
straight hole machined in advance. The experimental results indicate that machining efficiency
increases obviously. Various parameters affecting the forming of the cooling hole, such as voltages,
electrolyte concentrations, and the material of the workpiece, are discussed in detail. Furthermore,
the flow field and temperature field of the different type of cooling hole are analyzed using
computational fluid dynamics (CFD) model and finite element method. Result shows that the heat
transfer coefficient in rib channels could enhances significantly
Autoregressive Spectrum Analysis of Vibration and Condition Monitoring of Self-Propelled Rotary Tool
Authors: Hao Wangs Shen , Zhu Xun Sheng , Tian Biao Jun , Chi M.R.
Published: March 2009

Self-propelled rotary tools are being rediscovered for their applications in machining of
‘difficult-to-machine’ materials or for general improvement in the productivity of machining
operations. The vibration characteristic and the occurrence of chatter during high speed cutting will
induce the deterioration of precision and machining surface, tool wear and tool life. This paper deals
with the identification of the vibration in SPRT cutting system with AR time series model. The
experiment and deduction method provide a sound foundation for improving the structure with high
antivibration strength, which could reduce the relative vibration between tool and workpiece in the
alloweable scope.
Deposition of Smooth Diamond Films with High Adhesive Strength on WC-Co Inserts and Their Cutting Performance in Turning GFRP
Authors: Xue H.G. , Sun Fang Hong , Ma Y.P. , Chen Ming
Published: March 2009

Deposition processes of conventional diamond films and smooth fine-grained diamond
films on cemented tungsten carbide inserts (SCMT120408-HR, 6wt. %Co) in the hot filament
chemical vapor deposition (HFCVD) apparatus were investigated. A novel combined pretreatment
of Murakami’s reagent, acid etching and microwave plasma decarburization in Ar-H2 gas was
carried out. The adhesive strength of the films to the substrates, diamond-coated tool wear and
surface roughness of the workpiece were further studied by turning glass fiber reinforced plastics
(GFRP) cylindrical bars. Scanning electron microscopy (SEM), X-ray diffraction (XRD), energy
dispersive X-ray spectroscopy (EDX), and Raman spectroscopy were employed to characterize the
substrates and diamond films subjected to different pretreatments and deposition processes. Optical
microscope and surface scanning profilometer were utilized to monitor the evolution of tool wear
and surface roughness of the workpiece respectively during the cutting test. The experimental
results showed that the novel combined pretreatment was more effective in enhancing the adhesive
strength of diamond films to the substrate. Fine WC interlayer generated during the initial stage of
the diamond film deposition played an important role in improving the adhesion. Diamond coated
tools subjected to such pretreatment demonstrated up to 6 times longer tool life than uncoated ones.
Varied parameter deposition process produced smooth fine-grained diamond films, which led to
remarkably lower surface roughness of the workpiece in turning GFRP
Preparation of Targeting Vehicles for The Delivery of N-Bisphosphonates
Authors: Rodríguez-Lorenzo Luis M. , Fernandez M. , Parra J. , Vázquez Blanca , López-Bravo A. , San Román Julio , Gross Kārlis A. , Anderson Gail I.
Published: March 2009

Bisphosphonates (BP) are drugs currently administered orally to treat diseases characterised by an excessive bone resorption. Alternative and more efficient delivery routes and more potent compounds are being investigated. Three implantable delivery systems, which allow the controlled release of therapeutic agents from the device core, are examined in this paper. (4- (aminomethyl) benzene) bisphosphonic acid (ABBP) was incorporated on Ca8.8Na0.8(PO4)4.8(CO3)1.2(OH)0.4F1.6 particles by refluxing the powder in a 60 mmol suspension in acetone at 60°C for 5 hours. 4-aminophenyl acetic bisphosphonate monosodium salt (APBP) and 1- H-indole-3-acetic bisphosphonate monosodium (IBP) were loaded on Ca10(PO4)6(OH)1F1 ceramic bodies by stirring the ceramic bodies in 0.04M BP solutions. Injectable acrylic cements based on self-curing formulations of methyl methacrylate (MMA) and vitamin E were loaded with APBP and IBP. The incorporation of ABBP was confirmed by MAS-NMR spectroscopy. Modified powder shows two different phosphorous environments, the first one at 2.91 ppm can be assigned to the apatite base and the second one at 18.0 ppm has to be attributed to the phosphonic group of the ABBP. The IBP addition on ceramic surfaces did not decrease the number of osteoclast colonies and appeared to improve the performance of the HA as a surface for osteoblast culture. A therapeutic dosage of APBP and IBP can be achieved from acrylic cements that showed lack of toxicity and an increased cellular activity and proliferation.
In Situ Micro-XRD Structure Analysis of Bioapatite in Human Ribs
Authors: Wei Shan Shan , Tian Yi Ping , Li Hui , Guo Ling Hong
Published: March 2009

Structure parameters of minerals in human bone, bioapatite, are very important for biomaterials. In situ micro-XRD and Rietveld structure refinement were used to extract subtle structure information of human ribs. Rietveld refinement testified that lattice parameters, crystallite size and microstrain for cortical and cancellous bones were significant difference. Anisotropic crystallite sizes of human rib showed preferential growth of apatite along c-axis and the graded variation at radial direction of bone axis. The variations of the subtle structures of bioapatite, such as, P occupancy and P-O2 bond length, as well as distortion index of P-O tetrahedron, demonstrated the tendency of mineralization and the content of CO3 2- in human ribs.
The Optimized Design of a Double-Layer Flow Chamber
Authors: Zeng Ye , Lai Yi , Huang Hua , Liu Xiao Heng
Published: March 2009

The morphology, functions, and gene expression of blood cells and vessels, especially endothelial cells may be modulated by complex hemodynamic forces, as well as by chemical stimulation. Various models have been designed to simulate either the effects of blood flow or the chemical environment on these cells in an effort to understand their response. In this study, a double-layer flow chamber was developed to deliver different flow shear stress and to offer chemical factors, for mimicing the characteristics of both mechanic and chemical stimuli as in vivo conditions. The upper layer of the flow chamber is a main testing chamber (MTC), structured as a quadrate lumen, in which endothelial cells are seeded on the basal plane. The mechanical properties of cells exposed to flow shear stress can be recorded in real-time. The lower layer is a supplementary testing chamber (STC), which provides chemical stimuli. A partition microfiltration membrane exists between the two layers. The flow relationship among variables, such as the velocity, the shear stress, and the pressure distribution of the flowing in the chamber are achieved by using the nondimensional technique and the method of Bessel function of imaginary argument according to Navier-Stokes equations.
Wear Behavior of Enamel/Dentine and Veneering Ceramics
Authors: Gao Q.P. , Chao Yong Lie , Jian X.Ch. , Guo F. , Meng Y.K. , Wang H. , Cui Jun , Zhang Wei Qun , Tian Y.F.
Published: March 2009

This in vitro study compared the wear behavior between the enamel/dentine, two types of
dental veneering ceramics for all-ceramic restorations (Vita-alpha，Vintage -AL ). A variety of
factors including hardness, fracture toughness, flexural strength, frictional coefficients, wear scar
width, element concentrations were considered. The wear scars of the samples were characterized by
dynamic atomic force microscopy (DFM). The element concentrations of the surface before/after the
wear test were determined with energy dispersion spectrometry (EDS). In this study Enamel/dentine,
Vita-alpha and Vintage-AL have showed good wear resistance. The results also showed that there
were statistical significance in samples. The friction coefficient varied from time in each kind of
materials. The analytical differences between materials were observed in wear width and properties
of materials (p<0.05). The wear ability among four materials ranked from highest to lowest as
follows, Vintage-AL, Vita-alpha, enamel and dentine. DFM results demonstrated the wear patterns of
natural tooth detected as abrasive and denaturation of dental texture. Wear patterns of tested
veneering ceramics consisted mainly of abrasive wear, adhesion and fatigue wear and the different
pattern plays different roles in Vita-alpha and Vintage-AL. The EDS results showed the element
concentration of Fe was obviously found on the samples. Resistance ability against wear of veneering
ceramics is better than that of natural human teeth. And the ability may have some correlation with
the ceramics mechanical properties.
Fabrication of Porous n-HA/PA66 Composite for Bone Repair
Authors: Li Hong , Li Yu Bao , Yan Yong Gang , Li Ji Dong , Yang Ai Ping , Xiang Hong Zhao
Published: March 2009

Using nano-hydroxyapatite/polyamide66 composite (n-HA/PA66) and a special foamer as start materials, a porous species for bone defect repair was successfully developed by thermal-pressing method. The resulting material presented: (1) high compressive strength which reached 13~46MPa; (2) excellent porous structure, the average diameter of pores in the matrix was in range of 280μm to 500μm and porosity of 36% to 57%. The porous architecture could be adjusted by the combination of processing parameters such as the weight of start mixture used per mold and the ratio of composite to foamer as well as n-HA content in the composite. No apparent change in composition and structure of n-HA/PA66 composite was found by XRD and IR determination before and after formation of porous species. According to Sherrer equation, the value of D(002) of n-HA crystals in porous material and start powder were about 70nm, indicating no occurrence of change in size of n-HA during the thermal-pressing procedure. Additionally, no foamer residual was detected in porous species.
Fracture Mechanics and Toughening Mechanisms Analysis of Ce-TZP/Al2O3 Nanocomposite for Biomedical Applications
Authors: Pezzotti Giuseppe , Yamada Kiyotaka , Shiroyama S. , Nawa Masahiro
Published: March 2009

Zirconia ceramics were introduced in the seventhies for use as structural biomaterials after laboratory tests and simulator studies. However, nowadays concerns remain about their reliability in vivo, despite published clinical studies have already established the safety and the good tribological performance of these materials. It is still unclear what level of reliability can be achieved in ceramic biomaterials and how much their toughness level can be enhanced by microstructural design. The polycrystalline nature of ceramic materials may make both the observed properties and performance very scattered. In particular, the grain size and other microstructural features likely play a fundamental role in the mechanical behavior of the material. In this paper, we propose a set of fracture mechanics assessments, aimed to establish the quantitative amount of toughness achievable in a zirconia/alumina nanocomposite stabilized with cerium oxide (Ce-TZP/Al2O3 nanocomposite), and in situ confocal Raman spectroscopy to visualize toughening mechanisms, including polymorph transformation and residual stress fields stored around the crack path.
Effect of Sandblasting and Heat Treatment on Biaxial Flexure Strength of the Zirconia/Alumina Nanocomposite
Authors: Ban Seiji , Sato Hideo , Suehiro Y. , Nakanishi H. , Nawa Masahiro
Published: March 2009

The effect of sandblasting and heat treatment on biaxial flexure strengths of the
zirconia/alumina nanocomposite stabilized with cerium oxide (Ce-TZP/Al2O3 nanocomposite) was
evaluated in comparison to that of yttria stabilized tetragonal zirconia polycrystals (Y-TZP). The
disc-shaped specimens of the nanocomposite and Y-TZP were sandblasted with 70)m alumina
powder. After sandblasting, half of the specimens were heated at 1000°C for 5 min. The biaxial
flexure strengths of Y-TZP were independent on the sandblasting, but decreased with the heat
treatment. On the other hand, the biaxial flexure strength of the nanocomposite increased with the
sandblasting and significantly decreased with the heat treatment. The content of monoclinic ZrO2 of
Y-TZP and the nanocomposite increased with the sandblasting pressure and dramatically decreased
with the heat treatment. These results suggest that the stress-induced transformation from tetragonal
to monoclinic of the nanocomposite occurs more easily than Y-TZP.
Biomimetic Organic-Inorganic Nanocomposite Coatings for Titanium Implants. II. Biological "In Vitro" and "In Vivo" Characterization
Authors: Dutour Sikirić M. , Elkaim Rene , Lamolle S. , Ronold H.J. , Lyngstadass S.P. , Füredi-Milhofer Helga , Cuisinier F.
Published: March 2009

Biological mineralization proceeds within an organic matrix and is induced and controlled by extracellular, highly acidic matrix macromolecules. Our group has recently prepared organic-inorganic nanocomposite coatings by a strategy that closely mimics these processes. The strategy involves depositing a matrix of polyelectrolyte multilayers (PE MLs), alternating with layers of amorphous calcium phosphate (ACP) particles, then "in situ" growing nanosized apatite crystals within that matrix [1, 2]. Here we describe the results of biological "in vitro" and "in vivo" testing of these materials.
A Study of Bone-Like Apatite Formation on β-TCP/PLLA Scaffold in Static and Dynamic Simulated Body Fluid
Authors: Kang Yun Qing , Yin Guang Fu , Wang Ke Feng , Luo Lin , Liao Li , Yao Ya Dong
Published: March 2009

The ability of apatite to form on the surface of biomaterials in simulated body fluid (SBF) has been widely used to predict the bone-bonding ability of bioceramic and bioceramic/polymer composites in vivo. Porous β-tricalcium phosphate/poly(L-lactic acid) (β-TCP/PLLA) composite scaffold was synthesized by new method. The ability of inducing calcium phosphate (Ca-P) formation was compared in static simulated body fluid(sSBF) and dynamic simulated body fluid (dSBF). The Ca-P morphology and crystal structures were identified using SEM, X-ray diffraction and Fourier transform infrared (FT-IR) spectroscopy. The results showed that the typical features of bone-like apatite formation on the surface and the inner pore wall of β-TCP/PLLA. Ca-P formation on scaffold surfaces in dSBF occurred slower than in sSBF and was more difficult with increasing flow rate of dSBF. The ability of apatite to form on β-TCP/PLLA was enhanced by effect of each other that has different degradable mechanism. Porous β-TCP/PLLA composite scaffold indicates good ability of Ca-P formation in vitro.
Characterization of Crystalline Hydroxyapatite Thin Coatings for Biomedical Applications
Authors: Hong Zhen , Mello Alexandre , Luan L. , Farina Marcos , Andrade L.R. , Ferreira C.L. , Paik S. , Deng B. , Eon J.G. , Terra J. , Rossi Antonella M. , Ellis Donald E. , Ketterson J.B.
Published: March 2009

Crystalline hydroxyapatite thin coatings have been prepared using a novel opposing RF
magnetron sputtering approach at room temperature. X-ray diffraction (XRD) analysis shows that
all the principal peaks are attributable to HA, and the as-deposited HA coatings are made up of
crystallites in the size range of 50-100nm. Fourier transform infrared spectroscopy (FTIR) studies
reveal the existence of phosphate, carbonate and hydroxyl groups, suggesting that HA coatings
are carbonated. Finally, in vitro cell culture experiments have demonstrated that murine osteoblast
cells attach and grow well on the as-sputtered coatings. These results encourage further studies of
hydroxyapatite thin coatings prepared by the opposing RF magnetron sputtering approach as a
promising candidate for next-generation bioimplant materials.
Controlled Crystallization of Tooth-Like Hydroxyapatite under Gelatin Monolayer
Authors: Tian Kun , Guan Dong Hua , Wu Ping , Huang Chun Peng , Niu Lin , Xian Su Qin , Chen Yu , Wang Peng , Qu Yi Li , Ye Yong Mei , Wang Ting Ting , Chen Zhi Qing
Published: March 2009

Based on the molecular recognition theory, an organic molecules model was designed to
induce the hydroxyapatite crystallization, to build a tooth-like calcium phosphate/hydroxyapatite
under a controllable way in vitro. The cross-linking of collagen on the dentin surface and gelatin was
optimized by varying the molar ratio of N,N-(3-dimethylaminopropyl)- N'-ethyl-carbodiimide
hydrochloride (EDC) and N-hydroxysuccinimide (NHS) at a constant EDC concentration. CaCl2 and
Na3PO4-12H2O solutions were added after the crosslinking process. The whole process requires
repeating the crosslinking and mineralization process for five times. The obtained composite were
characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) as well as energy
dispersive X-ray photoelectron spectroscopy (XPS). The results showed that the dentinal tubule were
blocked by neonatal hydroxyapatite layer which has a continuous structure of columns crystal with
size of 10-40nm. Furthermore, there was column crystal with parallel direction inside, similar to the
crystal array in the top of enamel rod. This study showed that the specific organic molecule model can
be used as a potential effective crystal growth modifier.
Apatite Forming Ability of a Non-Woven Silica Fabric Containing Calcium
Authors: Rhee Sang Hoon , Chung Il Yong , Lee Yong Keun , Lim Bum Soon , Seol Yang Jo
Published: March 2009

Non-woven silica fabric was made by electro-spinning method for the potential application
as a bone grafting material. The silica gel, the source material for electro-spinning, was prepared by
the hydrolysis of tetraethyl orthosilicate in the presence of calcium salt, water, hydrochloric acid and
ethanol. It was transferred to a syringe, which was connected to the high voltage supply generating a
high electric field between the spinneret and the ground collecting drum. The silica fibers containing
calcium were spun under the electric field of 2 KV/cm. Their diameters were in the range from about
0.3 μm to 8 μm. It was heat-treated at 300 oC for 3 hours. After soaking in the SBF for 1 week, low
crystalline apatite crystals were observed to occur on their surfaces. From the results, it can be
concluded that the non-woven silica fabric containing calcium made by electro-spinning method and
then heat-treated has a bioactivity. It means it has a potential to be used as a bone grafting material
because of its apatite-forming ability, high surface area to volume ratio and high porosity.
Mechano-Chemical Synthesis of Biphasic Calcium Phosphates with the Various Ratio of HA and β-TCP
Authors: Tadjiev Timur R. , Chun Sung Su , Kim Suk Young
Published: March 2009

Biphasic calcium phosphate powders (BCP) of hydroxyapatite (HA) and tricalcium
phosphate (β-TCP) with the various ratio of HA to β-TCP were prepared by utilizing mechanochemical
synthesis. Calcium hydrogen-phosphate dihydrate (brushite, CaHPO4⋅2H2O) and calcium
carbonate (calcite, CaCO3) powders have been chosen as the starting materials. The original Ca/P
ratio of CaHPO4⋅2H2O - CaCO3 batch was set to be 1.67. A mixture of starting materials was milled
using a planetary mill (ZrO2 jar and balls) with water for 3, 4, 5, 6 and 7 hrs. The XRD study of
calcined powders was conducted for phase identification and for HA/β-TCP ratio as well. The
phases of the calcined powders were HA and β-TCP, and the HA/β-TCP ratio varied with the
milling time. The mass fraction of HA and β-TCP phases was calculated from the XRD intensities
of HA and β-TCP. The ratio of the mixture milled for 4 hrs and calcined at 900°C was
85(HA):15(β-TCP) (BCP 85/15) and the content of β-TCP increased with the milling time. It is
believed defective HA powder formed at relatively short period of milling time (less than 3 hrs The
research revealed that nanocrystalline BCP powders could be synthesized by an employment of a
medium-high energy mechanical activation at room temperatures (~25°C) without any preliminary
chemical processing.
Effect of Pamidronate on Protein Adsorption and Osteoblast Adhesion to Hydroxyapatite Bioceramics Scaffold
Authors: Luo En , Cui Jun , Gao Y. , Lin Yun Feng , Zhu S.S. , Hu J.
Published: March 2009

This study is to investigate the effect of PAM on protein adsorption and osteoblastic cells adhesion to HA bioceramics. PAM was immobilized on the surface of HA bioceramics for bone scaffold by chelating. The outermost layer of the specimens was analyzed by XPS and FT-IR. The protein adsorption test was performed using the 10% bovine calf serum absorbed on the specimens in vitro. The osteoblastic cells were inoculated and cultured on the scaffolds. SEM, MTT test and ALP activity test evaluated the cell attachment, proliferation and activity on the scaffolds. Characteristic peaks in XPS and FT-IR spectra indicated PAM being immobilized on the surface of the bioceramics. PAGE and 2-D DIGE results indicated that HA absorbed more acidic proteins, while PAM-HA absorbed more basic and neutral proteins.The cell culture test indicated that the cells actively proliferated on the scaffolds. There was no significant difference between the ALP activity of the cells cultured for 1d, 3d, 5d and 7d on PAM-HA and that of the controls. PAM had no obvious effect on the cytocompatibility of HA, and PAM-HA bioceramics could be used as bone scaffold with potential ability to improve osteogenesis.
Developments in Processing of Ceramic Top Coats of EB-PVD Thermal Barrier Coatings
Authors: Saruhan Bilge , Schulz Uwe , Bartsch Marion
Published: March 2009

Partially Yttria Stabilized Zirconia (PYSZ) based Thermal Barrier Coatings (TBC) manufactured by EB-PVD process are a crucial part of a system, which protects the turbine blades situated at the high pressure sector of aero engines and stationary gas turbines under severe service conditions. These materials show a high strain tolerance relying on their unique coating morphology, which is represented by weakly bonded columns. The porosity present in ceramic top coats affects the thermal conductivity by reducing the cross sectional area through which the heat flows. The increase in thermal conductivity after heat-treatment relates to the alteration of the shape of the pores rather than the reduction of their surface-area at the cross section. The studies carried out by the authors demonstrate that the variation of the parameters during the EB-PVD processing of PYSZ based top-coats alters the columnar morphology of the coatings. Consequently, these morphological changes affect primarily the thermal conductivity and eventually the Young’ Modulus which are the key physical properties of this material group. New ceramic compositions covering zirconia coatings stabilized with alternative oxides, pyrochlores and hexaluminates are addressed. Failures occurring in ceramic top coats mark the lifetime of TBC system and therefore, it is necessary that their performance should go beyond that of the-state-of-the-art materials. This context summarizes the research and developments devoted to future generation ceramic top coats of EB-PVD TBCs.
High Temperature Behavior of Coatings and Layered Ceramics
Authors: Dusza Ján
Published: March 2009

The present contribution summarizes the recent results in the field of high temperature properties of layered ceramics and thermal barrier coatings (TBC), mainly as regards their thermal shock resistance and creep characteristics. The thermal shock and creep behavior of layered ceramics are discussed with the main focus on the influence of layered composition and interlayer boundary on the creep behavior of the composite. In the last part the high temperature deformation and creep of TBC’s are discussed.
Recent Advances in Material Characterization Using the Impulse Excitation Technique (IET)
Authors: Swarnakar Akhilesh Kumar , Giménez S. , Salehi Sedigheh , Vleugels Jef , Van der Biest Omer
Published: March 2009

The Impulse Excitation Technique (IET) is a non-destructive technique for evaluation of
the elastic and damping properties of materials. This technique is based on the mechanical
excitation of a solid body by means of a light impact. For isotropic, homogeneous materials of
simple geometry (prismatic or cylindrical bars), the resonant frequency of the free vibration
provides information about the elastic properties of the materials. Moreover, the amplitude decay of
the free vibration is related to the damping or internal friction of the material. At present, IET is a
well-established non-destructive technique for the calculation of elastic moduli and internal friction
in monolithic, isotropic materials. Standard procedures are described in ASTM E 1876-99 and DIN
ENV 843-2. IET can also be performed at high temperature (HT-IET) using a dedicated
experimental setup in a furnace and constitutes a valuable tool in the field of mechanical
spectroscopy.
In the present work, the most recent advances in high temperature characterization using IET at
K.U. Leuven are presented: the deformation behaviour of WC-Co hard metals, softening
phenomena in TiB2, relaxation mechanisms in ZrO2 composites and “in-situ” monitoring of the
damage evolution in uniaxially pressed metallic green compacts during delubrication.
Characterization Methodology of the Interface in Multilayer Composites
Authors: Yeo H.C. , Guo N. , Huang Weimin , Du H. , Jian X.M.
Published: March 2009

The quality of the interfaces in multilayer composites is a critical issue in the reliability
testing of the composite product during the manufacturing process and in-service. Weak interfaces
have often gone undetected and may become potentially defective at a later stage. One example is the
interface between mold compound and silicon (MC/Si) in IC packaging. There is a desire to study the
interface quality quantitatively, so the potential defective area can be evaluated and identified early. In
this paper, a nondestructive evaluation methodology is proposed to measure the available strength of
the interface by using ultrasonic reflection coefficients. It is known that interface degradation can be
either due to poor manufacturing process and stress loading. Characterization of the interface quality
of the MC/Si interface is first conducted by measuring longitudinal ultrasonic wave reflections from
the interface samples fabricated under varying conditioning processes that simulate the degradation.
A combined test that measures the reflection coefficient of the interface under stress load has also
been conducted to quantify the effect of the load. Finally, it is shown that the overall effect on the
reflection coefficient and available strength of the interface is derived and can be used as a
quantitative indicator.
Metal-PZT Composite Piezoelectric Transducers and Ultrasonic Motors
Authors: Li Tao , Chen Yan Hong , Ma Jan , Boey F.Y.C.
Published: March 2009

Rotary and linear ultrasonic motors were developed in the present paper using metal-PZT
composite piezoelectric stator transducer configuration. The transducer consists of a concentric PZT
tube and a metal tube, which structurally improve the reliability of the stator transducer. The
developed transducer can provide a free vibration velocity of 0.9 m/s under 100 Vp-p at the resonant
state. The rotary motor and linear motor use the developed transducer as the driving component,
which produces the rotational motion to drive the motor. The rotary motor is able to achieve about
700 rpm no-load speed, above 2 mNm torque, maximum 70 mW output power and 50% efficiency
under driving voltage of 80 Vp-p. The linear motor produces rotational motion and linear motion
simultaneously. The linear speed of 5 mm/s can be achieved under the driving voltage of 50 Vp-p
under no-load state. Under the loaded state, maximum 8 N load has been observed to be moved by the
motor at a speed of 0.6 m/s. The maximum output power and efficiency of the linear motor are 9 mW
and 11%, respectively.
The Response Time of a Magnetorheological Fluid Squeeze Film Damper Rotor System
Authors: Zhu Chang Sheng
Published: March 2009

The response time of a rotor system on a magnetorheological(MR) fluid squeeze film
damper was measured experimentally. The effects of rotating speed, step voltage and rotor imbalance
on the response time were dealt with. It is shown that the MR fluid damper rotor system is a
second-order dynamic system. The rapid response time defined by the time taken for the vibration
amplitude to rise (fall) from 10 % (or 90%) to 90 % (or 10%) of the vibration amplitude difference
between the initial and final states is 0.05~0.7s in applying a step voltage and 0.01~1.225s in dropping
a step voltage, respectively. It is impossible for the response time to be within a few milliseconds. The
response time is determined not only by magnetic field strength, MR fluid specification, rotational
speed, but operation mode of the power supply. There is a zero initial delay time at either applying or
dropping the step voltage, which is caused by the magnetizing or de-magnetizing process.
Piezoelectric Activity and Sensitivity of Novel Composites Based on Barium Titanate-Hydroxyapatite Composite Ceramics
Authors: Bowen Chris R. , Topolov Vitaly Yu.
Published: March 2009

This paper describes the effective electromechanical properties of hydroxyapatite-BaTiO3
0-3 composites as a potential bone substitute material. The permittivity, d3j and g3j piezoelectric
coefficients are calculated for composites at a range of compositions and connectivities to understand
the relationships between composite composition and piezoelectric and dielectric properties. The
properties of the composites can be tailored by adjusting the volume fraction and aspect ratio of the
BaTiO3 particles and the shape and level of porosity in the hydroxyapatite matrix.
Optimization of Wavelet Packets Analysis for Damage Detection in Composite Materials
Authors: Yu Long , Yan Yun Ju , Jiang Jie Sheng , Cheng Li
Published: March 2009

A method based on entropy-based criteria is present to choose the optimal decomposition
of Wavelet Packets Analysis (WPA) for damage detection in composite materials. The structural
damage indexes constructed based on energy spectrum variation of the structural vibration responses
decomposed using WPA before and after the occurrence of structural damage usually generate a
complete binary tree to calculate its elements. Date mining is carried out in this paper by adoption
entropy as the criteria to choose the optimal decomposition tree. In the decomposition process, only
the sub-signals which contain main information of the original signal are decomposed to generate
next level sub-signals. New damage index is constructed based on the optimal decomposition. Then
the dimension of the damage index is reduced while still keeping its sensitive to damage. Whether
Artificial Neural Network (ANN) or genetic algorithm (GA) is used in the further process of telling
structural damage status from damage index, this reduction will make remarkable time saving.
Biocompatibility of Near-IR Sensitive Au-Based Nanoparticles as the Potential Drug Delivery Carriers
Authors: Zhang Bin , Huang Xiao Li , Ren Lei , Zhang Qi Qing , Tan Mei Chee , Chow Gan Moog
Published: March 2009

We successfully synthesized near infrared (NIR) sensitive Au(shell)-Au2S(core)
nanoparticles, where Au2S dielectric core was encapsulated by a thin gold shell. The cytotoxicity in
vitro and biodistribution in vivo of Au-Au2S nanoparticles was studied by using NIH3T3 cells and
KM mice, respectively. The quantitative analysis of Au in each tissue of mice was done by using the
Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Au-Au2S nanoparticles (< 300 μg/ml)
showed good biocompatibility. Au-Au2S nanoparticles were preferentially taken up by the liver and
spleen, and ultimately eliminated mostly in the feces.
Bio-Engineered Mesenchymal Stem Cell-Tricalcium Phosphate Ceramics Composite Augmented Bone Regeneration in Posterior Spinal Fusion
Authors: Chan Chan Wai , Qin Ling , Lee K.M. , Yeung H.Y. , Hu Yun Yu , Wong K.H.K. , Yip R.C.L. , Cheng Jack C.Y.
Published: March 2009

Grafting of autologous iliac crest and decortication approach in posterior spinal fusion
surgery has been the “gold standard”. However, the limited source of autograft has prompted
extensive research into bone substitute and biological enhancement of the fusion mass. In this study,
the application of stem cell therapy by tissue engineering method was investigated to enhance
posterior spinal fusion with -tricalcium phosphate ceramics in rabbit model. Rabbit bone marrow
derived mesenchymal stem cells were aspirated from trochanter region of proximal femur. The
mesenchymal stem cells were grown and directed to differentiate into osteogenic cells by
osteogenic supplement (ascorbic acid, -glycerophosphate and dexamethasone) in basal medium
(10% FBS in DMEM). The osteogenic cells were seeded on tricalcium phosphate ceramics for one
day (MSC group, n=6). The cell-ceramics composite was implanted onto autologous L5 and L6
transverse processes with decortication approach in posterior spinal fusion. The cell free ceramics
acts as control (Control group, n=6) and iliac crest autograft as positive control (Autograft group).
The spinal segments were harvested at week 7 post-operation. Manual palpation was performed
with spinal segments to assess any movement of L5-L6 vertebral joint. The stiffness of the joint was
considered as solid fusion. The specimens then were fixed by formalin and transferred to 70%
ethanol. The BMC and volume of fusion transverse processes of L5 and L6 was measured by
peripheral quantitative computed tomography.
In manual palpation, 50% solid fusion was found in MSC group, 60% in autograft group but
none in control group. Moreover, the BMC of L5 and L6 transverse processes in MSC group was
greater than autograft and control group (45%, 40% respectively, p<0.01). The volume of transverse
processes in MSC group was greater than autograft by 45% (p<0.01) and control group by 26%
(p<0.05). In conclusion, the mesenchymal stem cells derived osteogenic cells augmented spinal
fusion and bone mineralization.
Objective Quantification of Porous Structure in Orthopaedic Biomaterial Implants Using Micro Computed Tomography
Authors: Yeung H.Y. , Qin Ling , Lee K.M. , Leung K.S. , Cheng Jack C.Y.
Published: March 2009

Porous calcium phosphate ceramics have been widely investigated in orthopaedic
surgery as bone extensor. Attention has been given to manufacturing of a porous bioceramic that
mimics the trabecular bone structure for proper bone regeneration and integration. Although
different methods have been applied to manufacture the porous structure, it was unable to visualize
the pores and their interconnections within the ceramic and had objective measurement of the
calcium phosphate ceramics. With the advance of biomedical imaging through micro-computed
tomography (microCT), the study attempted to quantify the pore structure of different calcium
phosphate ceramics. Three kinds of bioceramic blocks, namely BSC, ChronOS, and THA, were
synthesized by three methods and tested in the study. Six blocks of each bioceramic were evaluated
by conventional water immersion method and microCT. The pore size and connectivity of the pores
were evaluated with standardized protocols. The three-dimensional analysis of the pores and their
distribution by microCT was presented. The ChronOS had more functional pores (200-400μm in
diameter) than the BSC and THA did (p<0.05). Providing objective information on the functional
pores, the microCT evaluation serves as a good standard for specification of the bioceramic-related
implants.
Effects of Processing Parameters on the Morphology and Size of Electrospun PHBV Micro- and Nano-Fibers
Authors: Tong Ho Wang , Wang Min
Published: March 2009

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) was used to fabricate micro- and
nano-fibrous, non-woven mats by electrospinning for potential tissue engineering applications. The
morphology and size of electrospun fibers were assessed systematically by varying the processing
parameters. It was found that the diameter of the fibers produced generally increased with
electrospinning voltage, needle diameter for the polymer jet and polymer solution concentration.
Beaded fibers were readily produced at low PHBV concentrations, whereas the needle was blocked
within a very short time during electrospinning when the PHBV concentration was too high. At the
polymer concentration of 7.5 % w/v, it was shown that beadless PHBV fibers could be generated
continuously by adjusting the electrospinning parameters to appropriate values. This study has clearly
demonstrated that electrospinning can be an effective technique to produce PHBV micro- and
nano-fibers. It has also been shown that composite fibers containing hydroxyapatite (HA) can be
produced using the electrospinning technique.
Failure Surfaces of Honeycombs with Plateau Borders under In-Plane Biaxial Loads
Authors: Yang Mei Yi , Huang Jong Shin
Published: March 2009

Ductile honeycombs under in-plane biaxial loads fail by elastic buckling, plastic yielding
and fast fracture of solid cell edges, while brittle honeycombs fail by elastic buckling, brittle
rupturing and fast fracture of solid cell edges. In the paper, we aim at summarizing the modeling
and theoretical expressions for describing the failure surfaces of honeycombs with non-uniform
thickness cell edges under in-plane biaxial loads. Hence, the failure surfaces of ductile honeycombs
with plateau borders are generated and found to be dependent on the solid distribution in cell edges
and the yielding strengths of solid cell edges. Also, the failure surfaces of brittle honeycombs with
plateau borders are significantly affected by the cell-edge modulus of rupture and the solid
distribution in cell edges.
Development and Impact Behaviors of AL Door Guarder Beam Reinforced with CFRP for Side Collision of Automobiles
Authors: Aoki Yoshio , Ben Goichi , Iizuka Yuka
Published: March 2009

Carbon fiber reinforced plastic (CFRP) laminates are used in the wide field, because they
have excellent properties of a specific strength and of a specific stiffness. The CFRP has a possibility
of weight reduction automotive structures which can contribute to improve mileage and then to
reduce Carbon dioxide. On the other hand, the safety of collision should be also made clear in the case
of employing the CFRP to automotive structures. In this paper, the Al guarder beam reinforced with
the CFRP is examined by an experiment and by a numerical analysis for replacing it to the
conventional steel door guarder beam equipped in the automotive door. The experimental relations of
impact load to displacement for the Al guarder beams with the different thickness of CFRP showed
the good agreement with those of numerical results. From the comparison of these results, the
numerical method developed here is quite useful for estimating the impact behaviors of Al guarder
beam with CFRP layer.
Mechanics Characteristics and Failure Criteria of Concrete Confined by Lateral Stress after Suffering Cycles of Freezing and Thawing in Seawater
Authors: Qin Li Kun , Chen Hao Ran , Wang Yu Jie , Zhao Dong Fu , Yao Jia Wei
Published: March 2009

Biaxial compressive tests of plain concrete specimens suffering 0、25、50 and 75 cycles
of freezing and thawing respectively in 3.5% sodium chloride solution imitated seawater were
completed under four lateral constant stress rates. The tests were completed by using the large
static-dynamic triaxial test system for concrete in the State Key Laboratory of Coastal and Offshore
Engineering, Dalian University of Technology. The biaxial compressive strength and deformation
characteristics of concrete confined by lateral stress after suffering corrosive cycles of freezing and
thawing were studied in a systematic way. On the basis of the tests, the failure criterion of concrete
subjected to constant lateral compressive stress after suffering corrosive cycles of freezing and
thawing was established in the stress-strain system. The conclusions can provide the testing and
theoretical basis for deeper study of the concrete construction subjected to biaxial compressive
combined loads in northern cold region or influenced by corrosive cycles of freezing and thawing
nearby the coastal and offshore area.
Effect of Coupling Agents and Particle Size on Mechanical Performance of Polyethylene Composites Comprising Wollastonite Micro-Fibres
Authors: Yuan Xiao Wen , Bhattacharyya Debes , Easteal Allan J.
Published: March 2009

The usefulness of rotational moulding (rotomoulding) as a polymer processing technique is
often limited by the selection of polymers, which in most cases happens to be polyethylene (PE). In
the present study, PE polyethylene was blended with wollastonite microfibres and maleated
polyethylene (as a coupling agent) with the purpose of developing an improved material for rotational
moulding. The incorporation of wollastonite fibres without any coupling agent improved the tensile
strength, but showed a reduction in impact strength. As expected, the most significant enhancement
due to wollastonite was in the tensile modulus.. The addition of a coupling agent improved both the
impact strength and the processability, especially when wollastonite was coated with aminosilane.
Scanning electron microscopy revealed good adhesion between the coated fibre reinforcement and the
polyethylene matrix at the fracture surface.
Morphology of Chromium in Cu- 2.0%~4.2%Cr Alloys
Authors: Fan Zhi Kang , Xiao Peng
Published: March 2009

The microstructures of Cu-Cr alloys with 2.0-4.2wt%Cr have been studied. Very little
dendritic copper was found in supereutectic Cu-Cr alloy containing 2.4wt%Cr. When Cr content
reached to 4.2wt%, square-like section Cr fibers other than round fibers were observed besides
primary dendritic chromium in the Cu-Cr alloy. The fibrous Cr particles are eutectic chromium
phase.