bluuebunny/crossref_metadata_2025 huggingface dataset:
Research on High Arch Dam Failure Probability Based on Failure Mode
Authors: Chen Zai Tie , Ren Qing Wen
Published: March 2009

In order to overcome the weakness in traditional high arch dam safety evaluation without
considering the randomness, failure mode and risk analysis, it is proposed to apply three indexes
namely failure probability, economic loss and life loss to high arch dam safety evaluation. On the
basis of the analysis of accidents and on-site measured data, expert discussion as well as analytical
analogy and by means of Fault Tree Analysis, a probe is made into the four major failure modes and
the causes of high arch dam failure, namely destabilization collapse, shear-slipping collapse, excess
cracking and man-caused destruction. Based on the calculating of the probability of high arch dam
shearing-slipping failure, the computational method and procedures are established by means of
Second Moment Method for the calculation of the occurrence probability of the major failure modes
of high arch dam. A study is made of the degree of correlation between the major failure modes and
of the method for calculating the high arch dam failure probability under multi-failure-modes.
Hierarchical Models of Chemical Infiltrated Carbon/Carbon Composites
Authors: Piat Romana
Published: March 2009

In the last years there has been an increasing interest in the multi-scale mechanics of the
materials, i.e. in predicting the macroscopic constitutive response on the basis of the underlying
microstructure. At each level of structural hierarchy, one may model the material as a continuum,
and the representative volume element problem can be formulated in terms of standard equilibrium
and boundary conditions. The overall physical behaviour of these micro-heterogeneous materials
depends strongly on the shape, size, orientation, properties and spatial distribution of their
microconstituents. For prediction of the macroscopic behaviour of such materials the multi-scale
homogenization techniques were developed.
As an example of such investigation we develop the hierarchical material model of the chemical
vapour infiltrated carbon fiber composites (CFCs) with a unidirectional or random distribution of
fibers. The approach based on hierarchical structural modeling can be used to theoretically predict
the mechanical parameters of CFCs with different microstructure and to develop virtual materials
with prescribed mechanical properties.
Fracture Analysis for Damaged Aircraft Fuselage Subjected to Blast
Authors: Ju Jin San , Jiang Xiu Gen , Fu Xiang Rong
Published: March 2009

This paper primarily presents the development and application of automation
computational analysis techniques to determine the dynamic stress intensity factor for the damaged
aircraft fuselage subjected to triangle blast load. A program based on automated procedure to
simulate cracked fuselage is developed. It may create 3-dimention panel model using
parameterization. The stress around the crack tips will be captured and the dynamic stress intensity
factor can be obtained at every moment of the blast automatically. A typical curved panel model
which consists of 7 frames and 8 stringers is calculated. The calculation results shown that the form
of the dynamic SIF curve is similar to that of the triangle load curve while the peak point of
dynamic SIF curve occurs a little later than that of the load curve due to the inertia effect. The
longer the crack is, the more obvious the effect is. The peak SIF value of the crack under blast load
is bigger than that under the static load for certain crack length. The longer the crack is, the bigger
the difference between the dynamic peak SIF value and static SIF is. At the same time, the load
time has effect on the dynamic SIF curve and its peak value. These results show good agreements
with theoretical principles.
Modeling of Material Parameters of Marine Concrete for Service Life Prediction
Authors: Yoon In Seok
Published: March 2009

It is a prerequisite to formulate material parameters affecting chloride penetration into
concrete. This paper is focused on defining intrinsic parameters of concrete, linking a theoretical
solution for durability design in submerged concrete under marine environment. Material parameters,
such as surface chloride content, chloride diffusivity, critical threshold critical content, chloride
binding capacity are formulated.
Failure Mechanism of Pure Nickel (Ni 200/201) under Thermo-Mechanical Loading
Authors: Koeberl Hubert , Winter Gerhard , Riedler Martin , Eichlseder Wilfried
Published: March 2009

Cyclic loading of metallic engineering components at constant elevated or fluctuating
temperature causes a complex evolution of damage which be can hardly be described in a unique
and straightforward manner. Often the thermal behaviour of the base metals is to weak, so thermal
barrier coatings were needed. Nickel is generally used for such thermal barrier coatings. Therefore
it is necessary to study the thermo-mechanical fatigue (TMF) of this material. The lifetime of these
coatings is very strong affected by the temperature loading in general, both described by nodal
temperatures and their local gradient. The thermal cyclic loading takes place as thermo-mechanical
and low cycle fatigue (LCF) damage regime. To classify the thermo-mechanical failure mechanism
of pure nickel, OP (out of phase) and IP-TMF (in phase) test series were examined. The use of
damage parameters like the unified energy approach make sense, a more detailed life time
calculation for pure Nickel can be done by using the Neu-Sehitoglu model. Summary, thermomechanical
loadings activate multiple damage mechanism. Surface embrittlement by oxidation is
the major distinctive mechanism in addition to pure fatigue damage. Different lifetime approaches
were tested and analysed to fulfil the requirements for the fatigue analysis of nickel made
components.
Debonding Failure Mechanism of Basalt Fiber Sheet Bonded on Concrete
Authors: Park Cheol Woo , Sim Jong Sung
Published: March 2009

Among various types of fiber reinforced polymer (FRP) materials, sheet-formed
materials are commonly used for the strengthening of reinforced concrete structures. Basalt fiber
sheet has shown a good durability to a harsh environmental condition comparing to other typical
fiber sheets, such as glass and carbon fiber sheets [1]. This study investigates the debonding failure
characteristics of the basalt fiber sheet for its application in the field. Fundamental mechanical
characteristics were evaluated prior to the bond fracture test. Experimental variables include the
number of fiber sheet layers, bonding length and bonding width. Debonding failure mode was
typical at the bonded interface and the failure strength increased as the number of layer increased.
From the results, the effective bond length and effective bond strength were calculated and
compared with the literatures. It was also found that the debonding failure strength was a function
of the bonding width rather than the bonding length. Based on the test data, an equation to calculate
the effective bonding length and strength was suggested.
Boundary Effect on the True Specific Fracture Energy of Concrete
Authors: Zhao Yan Hua , Xu Shi Lang , Wu Zhi Min , Gao Hong Bo
Published: March 2009

The apparent size effect of the specific fracture energy of concrete according to the
RILEM procedure has been confirmed by numerous published works. The paper offers an
explanation for this size effect by considering the specimen boundary influence on local fracture
energy over the ligament length, which is closely associated with the measured fracture energy of
concrete. To address this boundary influence, boundary affected length is introduced, over which
local fracture energy is different from that in the bulk far away from the surface of the specimen.
Based on previous work, a continuous smooth function is hypothesized to simulate the distribution
of local fracture energy. At the same time, the model established was compared to the existing
models, i.e. Perturbed Ligament Model (PLM) and Bilinear Model (BLM). Some test results from
wedge splitting specimen in the literature were used to verify these three models. The results show
that the true fracture energy of concrete, irrespective of the specimen size, could be obtained from
the measured values directly from RILEM, and is less sensitive to determination approach. The
predicted boundary affected length when the crack reaches the specimen surface is more close to
the value of the perturbation length in PLM.
Probabilistic Analysis of Three-Dimensional Beams with Uncertain Damage
Authors: Gentilini Cristina , Nobile Lucio
Published: March 2009

This paper deals with a simple and reliable method for the probabilistic characterization
of the linear elastic response of frame structures with edge cracks of uncertain depth and location in
the three-dimensional setting. A numerical test evidences the performance of the approach.
Flexural Capacity of Reinforced Concrete Member Retrofitted with Carbon Fiber Sheet
Authors: Seo Soo Yeon , Kim Kyong Tae , Yun Hyun Do , Choi Ki Bong , Yoon Seung Joe
Published: March 2009

The purpose of this paper is to evaluate the structural capacity of Reinforced Concrete (RC)
member retrofitted with Carbon Fiber Sheet (CFS) in order to improve the flexural strength. Eleven
RC beam specimens are made and retrofitted with CFS by following the test objective. The main
factor in selecting the test parameters is to verify the bond capacity of CFS. Therefore, parameters
such as layer number of carbon fiber sheet, strengthening method, bonding ratio (100%-80%), and
epoxy type are considered in the test. From the test, all specimens showed little bit different behavior
each other. Especially, the flexural capacity was not linearly increased even if the layer number of
CFS increased when it was more than two. Also the specimens with the low bonding ratio exhibited
low strength as well as premature bond failure on comparing to other specimens.
Applicability of Sub-Size Charpy Specimens to Transition Behaviour of RPV Materials
Authors: Falcnik Michal , Novosad Petr , Pesek Pavel , Kytka Mylos
Published: March 2009

The advancement of proper methodology to determination of VVER reactor pressure
vessel (RPV) materials transition behaviour has been followed. The project included selection of
proper specimen geometries (standard 10x10x55 mm, sub-size 3x4x27 mm and 5x5x27.5 mm
Charpy-V samples) and impact as well as dynamic fracture toughness testing. All the fundamental
criterions have been applied to consider an applicability of small-sized specimens to Cr-Mo-V and
Cr-Ni-Mo-V steel radiation embrittlement studies. Selected specimen geometries have been found
to be fully valid for impact and dynamic fracture data and capable for prediction of standard
specimen behaviour from the small specimens. Within testing of irradiated materials, it has been
found not fully validity of all the compared transition temperatures.
Fabrication and Microstructural Change of PMN-PT Thin Films on Si Substrates by PLD with Mask and Double-Pulse Lazer Excitation
Authors: Hayashi Shogo , Wakiya Naoki , Kiguchi Takanori , Tanaka M. , Shinozaki Kazuo
Published: March 2009

Epitaxial Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) thin films were fabricated on (La,Sr)CoO3/CeO2/
YSZ coated Si substrates by double-pulse excitation PLD with and without a mask. For
double-pulse excitation PLD without a mask in conditions of Nd:YAG laser irradiation before
defocused KrF-excimer-laser irradiation, the surface roughness of PMN-PT thin films was rather
less than that of the films fabricated using Nd:YAG single laser PLD. Thin films with smoother
surfaces were deposited at the high deposition rate of 5.6 nm·min-1 using the mask and the
double-pulse excitation PLD method in conditions of irradiation of Nd:YAG laser after KrF
excimer laser at 0.5 =s delays.
Oxygen Reduction Electrode Properties of the Ba(Ce, Gd, Ru)O3-δ Oxides in Alkaline Aqueous Solution
Authors: Toda Haruhiko , Chuma Takeshi , Saito Morihiro , Kuwano Jun , Shiroishi Hidenobu
Published: March 2009

Two series of compositions, BaCe0.8-xGd0.2RuxO3-δ (BCGRx, x=0-0.8) and
BaGd1-yRuyO3-δ (BGRy, y=0.5-1.0), were synthesized and their crystal phases were
examined. The BCGR0.15 and BGR0.5 oxides were a single phase of perovskite solid
solution, while BCGR0.67 and BGR0.67 were a perovskite-related superstructure phase.
The onset voltage (Vo) of the reduction current and the efficiency (E4) of the
4-electron reduction of oxygen were evaluated by semi-steady state voltammetry with
rotating ring-disk electrodes. In the BCGRx series, the activities for electrochemical
oxygen reduction (EOR) increased with increasing Ru content. In the BGRy series, the
BGR0.67 superstructure phase showed a higher EOR activity than the perovskite BGR0.5
and the hexagonal(4H) BaRuO3. This indicates that the EOR activity depends on the
crystal phase. The BGR0.67 exhibited the best EOR activity of all the samples. The Vo
value was 0.80 V vs. reversible hydrogen electrode and the E4 value was almost
100 %.
Lithium Battery Properties of LiNi0.5Mn1.5O4 Powders Synthesized by Internal Combustion Type Spray Pyrolysis Apparatus Using Gas Burner
Authors: Mukoyama Izumi , Myoujin Kenichi , Nakamura Takahiro , Ozawa Hironori , Ogihara Takashi , Uede Masao
Published: March 2009

Spherical LiNi0.5Mn1.5O4 powders were prepared by internal combustion type spray pyrolysis
apparatus using gas burner. The powder production capacity was 1 kg/h by this equipment. After
calcinations of as-prepared powders contained Ni at different temperatures from 800 to 1200 °C in
air for 10h, LiNi0.5Mn1.5O4 powders were obtained. As-prepared particles have a porous
microstructure with an average diameter of about 5 μm with narrow size distribution. XRD showed
that LiNi0.5Mn1.5O4 powders were well crystallized to a spinel structure with Fd3m space group.
LiNi0.5Mn1.5O4 powders calcined at 1000°C show good cycle performance with after 30 cycles
discharge capacity of 112mAh/g and 95% retention after 400 cycles between 3.5 V and 5 V.
Material Design for High Strength NTC Thermistor Ceramics
Authors: Miura Tadamasa , Nakayama Akinori , Niimi Hideaki , Tamura Hiroshi
Published: March 2009

Various factors were investigated to decide the mechanical properties of (Mn1–xNix)3O4 ceramics,
that are typical composition systems of NTC (negative temperature coefficient) thermistors. The
strength of NTC thermistor ceramics can be improved by designing the material so that the
compressive stress may remain at the surface of the ceramics. At high temperature, the thermal
expansion coefficient of a rock salt phase segregated internally ceramic increases over that of the
spinel phase, further, on the surface of the ceramics, this compressive stress remains below room
temperature. Moreover, it was confirmed that the stress analysis result by the FEM corresponded
well with the stress measurement result on the surface of the ceramics measured by μ -XRD.
Evaluation of Composite Electromagnetic Wave Absorber made of Polystyrene Resin and Permalloy or Sendust
Authors: Sakai Kenji , Yoshikado Shinzo
Published: March 2009

The frequency dependences of the complex permeability μ r*, complex permittivity ε r*, and return loss were investigated for composite electromagnetic wave absorbers made of soft magnetic materials (permalloy or sendust) and polystyrene resin. For permalloy, two types of particle shape were used: grain-type or flake-type. The volume mixture ratio of magnetic materials was varied in the range from 40 % to 70 %. The values of the real part μ ’ and imaginary part μ ” of μ r * increased with increasing mixture ratio of magnetic materials. The frequency dependence of μ r * for flake-type permalloy composite was similar to that for sendust composite. All absorbers showed the absorption of electromagnetic waves in the frequency range above 1 GHz.
Preparation and Conductivity of TiO2-Doped Y2O3-Stabilized ZrO2 Ceramic
Authors: Lei X.L. , Zhang Dong Ming , Zhang Lian Meng
Published: March 2009

Nano-scale 8mol% titania doped yttria stabilized zirconia (8TiYSZ) powders were
prepared by coprecipitation combined with azeotropic distillation process. Powder X-ray
diffraction, BET method and TEM were performed to characterize the powder properties. The
relative density of 8TiYSZ sample sintered by spark plasma sintering technique at 1150°C for 3min
reached 99%. The electrical conductivity of sintered pellet was much higher than the reported one.
Study on the Possibility of the Application of Metal Matrix Composites on Extendible Exit Cone Nozzles
Authors: You Jun Feng , Zhang Du O , Ouyang Qiu Bao , Su Jian He
Published: March 2009

This work studied the possibility of the application for Metal Matrix Composites (MMCs)
in extendible exit cone nozzles (EECNs), through analyzing the stress distribution on the solid
rocket motor’s EECNs. The result shows that the MMCs can be used on the EECNs. With replacing
the traditional steel by light MMCs to serve as the key supporting components, the strength and
stiffness can satisfying the application request. The mass of the components are drastically
decreased. This technique has promising applications.
Development and Photoluminescence of ZnO-ZnS Core-Shell Nanotube and Nanorod Arrays
Authors: Kuo Pai Chia , Chen San Yuan , Bow Jong Shing
Published: March 2009

After the wurtzite ZbS nanorods were synthesized by hydrothermal treatment in the
presence of ethylenediamine (en) aqueous solutions at 200oC, ZnS-ZnO core-shell nanorods were
readily obtained by annealing ZnS nanorods under oxygen at 650oC for 3-5 min. A strong broad peak
in the 450–550 nm visible range was clearly detected and its peak intensity could be greatly enhanced
after the ZnO shell was developed on hydrothermal ZnS nanorods. On the other hand, using AAO as
a template, ZnS-ZnO core-shell nanotubes could be synthesized using atomic layer deposition
process along with the sulfuration conversion of the ZnO nanotube array. This ZnO-ZnS core-shell
nanotube structure could be confirmed by x-ray photoelectron spectroscopy (XPS) analysis. In
addition, an enhanced UV emission along with the reduced visible emission was also detected for the
ZnO/ZnS core-shell nanotubes..
Investigation of Hot-Pressed Al2O3-Cr2O3/ Cr3C2 Nanocomposite
Authors: Lin Hao Tung , Huang Jow Lay , Wang Sheng Chang
Published: March 2009

Nanoscaled Cr2O3 powders coated on alumina particles have been produced by means of metal organic chemical vapor deposition (MOCVD) in a fluidized bed, using the pyrolysis of Cr(CO)6 precursor. In order to prepare the nanoscaled Cr3C2 powder from the Cr2O3, carbonizing behavior of the Cr2O3 particles was investigated. The carbon is from the decomposition of Cr(CO)6. It was found that Cr2O3 transformed into Cr3C2 at 1150 oC in graphite furnace in a vacuum level of 10-4 torr, while it could not carbonize at 1150oC in a vacuum level of 100 torr. In the present study, two reactions for Cr2O3 are carried out. One is that Cr2O3 reacts with Al2O3 to form a solid solution; the other is that Cr2O3 reacts with carbon to transform into chromium carbide. Consequently, a nanocomposite comprising the matrix of solid solution of Al2O3 - Cr2O3 and second phase Cr3C2 was prepared after hot-pressed.
Improving the Microstructure of Si3N4-TiN Composites Using Ammonium Citrate to Disperse Raw TiO2 Powders
Authors: Zheng Shan , Gao Lian , Watanabe Hiroshi , Tatami Junichi , Wakihara Toru , Komeya Katsutoshi , Meguro Takeshi
Published: March 2009

Dense and homogenous Si3N4-TiN composites (5 vol% TiN) were prepared by using in situ
synthesis method from Si3N4, AlN and TiO2 mixtures, containing Y2O3 and Al2O3 as sintering aids. In
the prepared Si3N4-TiN composites, TiN grains were formed from TiO2 and AlN powders during the
sintering process, in which ammonium citrate was used as a dispersant for raw TiO2 powders. The
microstructures of the Si3N4-TiN composites with the increase of ammonium citrate were
investigated by scanning electron microscopy (SEM). Citrate ions modified on the surface of TiO2
particles and protected the TiO2 particles in the mixed slurry to reduce the aggregations of TiO2
powders, and homogenous Si3N4-TiO2-AlN composite powder was prepared for sintering. The
microstuctures of Si3N4-TiN were developed after sintering with the uniform distribution of TiN
grains in the Si3N4 ceramics. It was found that the microstructure of Si3N4-TiN composite was
improved significantly with 0.20 g ammonium citrate in the system, TiN grains with 0.2-0.3 μm in
diameter distributed throughout Si3N4 matrix. It was a practical and useful way to improve the
microstructure of Si3N4-TiN composite without the alteration of the preparation procedure.
Development of Ceramic Thermoelectric Oxides for Generator
Authors: Noudem Jacques G. , Lemonnier S. , Prevel M. , Reddy E.S. , Guilmeau E. , Goupil C.
Published: March 2009

In this work we describe (i) the fabrication of thermoelectric modules based on oxide
bulk and foam materials of Ca3Co4O9 and Ca0.95Sm0.05MnO3(ii) and the metal to ceramic contacts
preparation. The open porous foam structures of thermoelectric materials can result in designing
efficient thermoelectric modules for waste heat sources involving gaseous and liquid media. The
possibility of direct large area physical contact of thermoelectric foam elements with hot media will
make them efficient electric power generators. The open porous thermoelectric materials with holes
can be a good candidate to confine phonons (lattice vibrations) in order to reduce the thermal
conductivity if the pores can be made sufficiently small. The performances of the modules were
evaluated and possible factors limiting their theoretical performance are discussed. A parameter
representing the quality of the modules termed as manufacturing factor (MF) representing the
cumulative effect of various factors involved in the fabrication process is introduced and evaluated
for the modules and compared to the reported modules.
Piezoceramic Switches for Optical Fibres
Authors: Haemmerle E. , Leung M. , Razak K.A. , Hodgson M. , Gao Wei
Published: March 2009

This paper describes a new optical switching concept using the deflection of a piezoelectric tube manufactured by an electrophoretic deposition process. A prototype optical switch has been assembled and some of the performance characteristics have been measured, such as an insertion loss of 0.9dB, crosstalk of -47dB and switching speed from 5-15ms. The system for measuring deflection has been custom-designed and built with a measurement accuracy of 1μm. Future work involves the improvement of the piezoelectric tube performance characteristics and combining all switching components in one case so that the switch can be tested in a real network environment.
Hydroxyapatite Formation on MOCVD-CaTiO3 Coated Ti
Authors: Sato Mitsutaka , Tu Rong , Goto Takashi , Ueda Kyosuke , Narushima Takayuki
Published: March 2009

Ca-Ti-O films were prepared by MOCVD using Ca(dpm)2 and Ti(OiPr)2(dpm)2 precursors. The phases, composition and morphology of Ca-Ti-O films changed depending on the molar ratio of Ca to Ti precursors (RCa/Ti), total pressure (Ptot) and substrate temperature (Tsub). CaTiO3 films in a single phase were obtained at Tsub = 973 and 1073 K. CaTiO3 films prepared at 873 K had a dense structure and smooth surface. CaTiO3 films prepared at Tsub = 1073 K had complicated rough surface with a cauliflower-like texture. Hydroxyapatite (HAp) formed in 3 days on the CaTiO3 film prepared at Tsub = 1073 K.
Assessment of Fatigue Life for High-Temperature Pipeline Welds Using X-Ray Diffraction Technique
Authors: Yoo Keun Bong , Kim Jae Hoon
Published: March 2009

The objective of this study is to examine the feasibility of the X-ray diffraction method for the
fatigue life assessment of high-temperature steel pipes used for main steam pipelines, re-heater pipelines
and headers etc. in power plants. In this study, X-ray diffraction tests were performed on the specimens
simulated for low cycle fatigue damage, in order to estimate fatigue properties at the various stages of
fatigue life. As a result of X-ray diffraction tests, it was confirmed that the full width at the half maximum
(FWHM) decreased with an increase in the fatigue life ratio, and that the FWHM and the residual stress
due to fatigue damage were algebraically linearly related to the fatigue life ratio. From this relationship, a
direct assessment of the remaining fatigue life was feasible.
Crack Growth Mechanisms from 3-D Surface Flaw with Varied Dipping Angle under Uniaxial Compression
Authors: Guo Y.S.H. , Wong R.H.C. , Chau K.T. , Zhu Wei Shen , Li Shu Cai
Published: March 2009

A number of instability problems in rock engineering projects are caused by crack
propagation. However, crack growth mechanisms from 3-dimentional flaw are not fully understood,
in particular for 3-D flaw case with varied dipping angle. This study focuses on 3-D surface flaw
using real rock specimens containing a flaw with varied inclination angle α from axial loading and
dipping angle γ from specimen surface under uniaxial compression. Acoustic emission technique
was used for tracing the initiation and growth of micro-cracks inside of specimen. It was found that
crack growth process is affected by the dipping angle γ of the 3-D flaw. When dipping angle γ ≠ 90º,
the thickness of rock above the flaw plane is thinner than that of below the flaw plane. As a result,
compressive crack and wing crack initiated easily from the thinner flaw tips. And, the normalized
stress for crack initiation σi /σc, AE events and the AE energy for crack growth decreases with the
dipping angle γ. However, for γ = 90º, the thickness of rock above and below of the flaw tips is the
same, it was observed that anti-wing crack (crack growth direction opposite to wing crack) initiated
first at a certain place away from the flaw tips, then wing crack and compressive crack emerged at
the late stage. For this case, the stress σi /σc, AE events and the AE energy for crack initiation and
propagation are at a high value. Thus, for rock mass contains flaws geometry with small dipping
angle, some problems of crack propagation may be induced easily during excavation.
Structural Strength and Buckling Analysis for a Steel Derrick after its Members Removed Partly
Authors: Liang L.H. , Gao Zeng Liang , Wang S.N. , Wu Q.Y. , Zhu J.X. , Wu M.B.
Published: March 2009

The static strength and stability of a derrick structure (78.5m high) after its members
removed partly are researched. The derrick is modeled by three-dimensional spatial beam elements
based on ANSYS. By the static analysis, the strength of the derrick after its member removing
partly is larger than that of the original derrick structure since some loads disappear. From the
buckling analysis, it can be found that the stability reduces drastically when removing some
members.
Study of the Wettability between Diamond Abrasive and Vitrified Bond with Low Melting Point and High Strength
Authors: Zang Jian Bing , Lu Jing , Wang Yan Hui , Zhang Xiang Hong , Yuan Yun Gang
Published: March 2009

The adhesion between diamond grits and the bond strongly influence the properties of diamond tools. Since diamond is covalent crystal, the high interfacial energy leads to the poor interface bonding between diamond grits and the bond. Furthermore, the sintering temperature of traditional vitrified bond is also very high because of the high refractoriness of alkalis containing in the bond, resulting in serious thermal damage to diamond grits. In this paper, a low melting point and high strength vitrified bond has been prepared mainly from borate glass, clay and lead glass. The bond is completely glassy above 850°C and the bending strength of the bond sintered at 850°C for 7 minutes is 125.7MPa with a 6.5:3.5 corundum/bond ratio. Moreover, this bond possesses good wettability with diamond abrasive from 600°C to 850°C.
Numerical Simulation Study on Truing and Dressing of Bronze-Bonded Diamond Wheel with Pulsed Laser
Authors: Chen Gen Yu , Mei Li Fang , Zhang Bi , Zhu Ding Jun , Chen Guo Gui
Published: March 2009

A two-dimensional mathematical model is developed to simulate laser truing and dressing of bronze-bonded diamond grinding wheel. Based on the model, the ablation depth produced on bond and diamond abrasives by an acousto-optic Q-switched YAG pulsed laser under different parameters as well as the temperature field on grinding wheel surface produced in the laser ablation process are numerically simulated. An experimental study on laser truing and dressing of grinding wheel is also conducted. In the study, the wheel surface is ablated by the single-pulsed laser and measured with a measurement device for surface topographic information. Both the theoretical analysis and the experimental results indicate that the truing and dressing processes can be simultaneously realized with the laser ablation as a single process.
Experimental Research on Erosion and Corrosion of WC-Base Matrix Materials for Drill Bits under Impingement of Drilling Muds
Authors: Duan Long Chen , Neville Anne , Yan Yu
Published: March 2009

In oil drilling the failures of PDC drill bits are exhibited as erosive wear, dropping and
breaking of cutters, so the erosion and corrosion resistance of the matrix is one of the key factors
affecting the quality of PDC bits. In order to understand the degradation mechanism of matrix
materials for drill bits, a kind of loop recirculation rig is adopted to measure total mass loss TML,
mass loss E by pure mechanical erosion, and then through calculation the mass loss C+S by
corrosion and synergy is obtained. The tested and calculated results show that TML of matrix
materials is not only caused by pure mechanical erosion, but also by corrosion and their synergy of
mechanical erosion and corrosion. In the discussed scope of this paper the volume loss produced by
corrosion and synergy is 24.16% of the total volume loss (TVL) at most, which tells us that the
corrosion resistance of matrix materials should be considered carefully besides their erosive
resistance in the design and selection of PDC drill bits used in the corrosive drilling muds.
Research and Practice on the On-Line Measurement of Cylindricity Error in a Grinding Machine
Authors: Zhang Lei , Zhao Ying , Ba Lin
Published: March 2009

This paper researches the theory of multi-probes EST (Error Separation Technique) further.
The computer simulation on the three-probes EST is also carried out. Several contrastive experiments
of the on-line measurement are carried out in a grinding machine (MB1332A). The workpieces used
in the experiments had been measured by TALYROND 262 Geometrical Error Measurement
Instrument. The results of these experiments successfully verify that the theory and mathematical
models of this paper are correct. The contrast of the measuring results in these experiments proves
that the three-probes method can realize the complete separation of all kinds of errors basically and
this method is applicable to on-line measurement of a workpiece and it can also make the
measurement accuracy very high.
Real Time Thermal Error Modeling and Compensation of 5-Axis NC Grinding Machine Tool
Authors: Wang Xiu Shan , Yang Jian Guo , Wu Hao , Yan Jia Yu
Published: March 2009

The thermal error model of the 5-axis grinding machine tool was acquired by the
homogeneous coordinate transformation, including 17 thermal error components. The thermal
volumetric error real time compensation model was built by using the multiple regression analysis.
The thermal error compensation control system and the temperature sensing system were developed
and used as real-time compensation for the 5-axis grinding machine tool.
Experimental Study on the Hardened Surface Layer of Grinding SKD-11 Hardened Steel
Authors: Ming Wei Wei , Liu Gang , Chen Ming
Published: March 2009

The grind-hardening process integrates heat treatment processing into the production line,
reduces the number of producing procedures, shortens machining period and lowers the cost.
Meanwhile, grind-hardening machining doesn’t use cutting fluid. So the grind-hardening process is
a green manufacturing method with an extending application in future. Grinding hardening is an
effective method in machining SKD-11 hardened steel due to its good quenched property. In this
paper, the grind-hardening characteristics of SKD-11 hardened steel are discussed, and the impacts
on the hardened surface layer varying with the grinding parameters are also studied. Optimization
of grinding parameters of SKD-11 hardened steel is conducted based on the study.
Study on Mechanical Polishing for CVD Diamond Films of Forming Nucleus Surface and Growing Surface
Authors: Chen Rong Fa , Zuo Dun Wen , Lu Wen Zhuang , Li Duo Sheng , Xu Feng , Ji Tong , Wang Min
Published: March 2009

In the present work, high power DC arc plasma jet chemical vapor deposition (CVD) is used to prepare diamond films with full width half magnitude (FWHM) less than 10 wave numbers at 1332 cm−1 Raman peak. During the polishing process, diamond film is hold against the stainless steel holder, which rotates and swings when the sample comes into contact with the cast-iron plate. Average surface roughness of the forming nucleus polished surface and growing polished surface is 560nm, 90nm respectively. And the materials removal rate is quite different. Fine crystal grain of the forming nucleus surface and the thick column crystal of growing surface are dominant in structure. In the meantime, effects of the size of the abrasive power, the applied force and polishing direction are also discussed. A profilometer, an Raman spectroscopy, X-ray diffraction and a scanning electron microscope have been used to evaluate the surface states of diamond films before and after polishing. This result reveals an. improvement of polishing efficiency and a great potential for commercial application.
New Thought for Designing the Multi-Phase and Multi-Scale Nanocomposite Ceramic Tool Materials
Authors: Liu Han Lian , Huang Chuan Zhen , Teng Xin Ying , Wang Hui
Published: March 2009

The new thought for designing the multi-phase and multi-scale nanocomposites was
proposed to improve the comprehensive mechanical properties. Multi-phase and multi-scale
particles are added to the matrix, and one of the additives is nano-scale particle, thus the
comprehensive mechanical properties can be improved by the synergic effects of micro-scale
toughening, nano-scale strengthening and mutual benefit between multi-phases. The ideal
microstructure of multi-phase and multi-scale nanocomposites was designed. With this
microstructure, the trans/intergranular fracture modes can be formed, which will consume more
fracture energy during the crack propagation, therefore, both the flexural strength and fracture
toughness can be improved. An advanced ceramic tool material has been fabricated based on this
new thought.
A Mechanistic Model of Material Removal in Magnetorheological Finishing (MRF)
Authors: Chen Feng Jun , Yin Shao Hui , Yu Jian Wu , Ohmori Hitoshi , Lin Wei Min , Uehara Yoshihiro
Published: March 2009

According to the sharp rheological characteristics of magnetorheological fluid in the magnetic field, the principle and mechanism of magnetorheological finishing is analyzed. Based on the Preston equation, the Reynolds equation and its boundary conditions, the two-dimensional material removal model is built and simulated. Furthermore, a series of MRF experiments are carried out, and the influence of the immersed depth and material kinds on material removal rate are clarified respectively. The experimental results are compared with the modeling results of material removal rate to confirm the mechanistic model validity.
Fabrication of WC-6Co-1.5Al (wt%) Hardmetal by High Energy Milling and Electrical Current Sintering
Authors: Li Xiao Qiang , Li Yuan Yuan , Long Yan , Shao Ming , Zhang Jian Bing
Published: March 2009

Ultrafine grain WC hardmetals were manufactured successfully from mixed powders of
nominal composition of WC-6Co-1.5Al(wt%). To manufacture bulk ultrafine grain WC alloys,
nanocrystalline WC powders as precursor were prepared for sintering from the mixed commercially
available powders by high energy milling of 15 h. Then the electrical current sintering process of
the milled powders was further studied. Experimental results showed that the density, hardness and
transverse rupture strength of the sintered alloys reached 14.224 g/cm3, HRA 94 and 1660 MPa,
respectively, by a appropriate coupling of pulse- and subsequent constant-current sintering and with
the total sintering time of 6 min. It seemed difficult to obtain desirable sintered hardmetal by a
single type of electric current sintering. However, the application of intensive pulse electric current
was favorable to sintering, although it was difficult to achieve good WC alloys only by the pulse
electric current sintering. A higher density WC alloy could be prepared by enlarging the electric
current when only constant electric current was applied to sinter the milled powders. Unfortunately,
the WC grains substantially coarsened concurrently so that the mechanical properties of the as
sintered alloy decreased obviously.
Two Domensional Simulation of Velocity Field of Two-Phase Flow for Gas and Solid in the Abrasive Air Jet Nozzle
Authors: Huang Chuan Zhen , Hou Rong Guo , Liu Zeng Wen , Li Quan Lai , Zhu Hong Tao
Published: March 2009

Simulation on velocity field of gas-solid flow in the abrasive air jet nozzle was studied by
the computed fluid dynamics(CFD) software. The velocity field of the two-phase flow in the
abrasive air jet nozzle can be obtained by means of simulation. The effect of the nozzle diameter on
the velocity field shows that the velocity field in the nozzle with a smaller diameter is more
well-distributed. The velocity distribution along the nozzle axis and the radial direction of the
nozzle outlet was also simulated.
Real-Time Measurement and Compensation for Wheel Wear in Curve Grinding Based on Image Processing Method
Authors: Luo Yu Mei , Hu De Jin
Published: March 2009

This paper deals with an application to automatic compensation of grinding wheel wear by
an image processing based real-time measurement method in dry curve grinding. An online image
measurement system was schemed out and its principle was introduced in detail. Real time image of
workpiece and grinding wheel is grabbed by CCD camera during grinding process. For the purpose of
increasing the measurement precision, a new sub-pixel level accuracy edge detection approach
combining Zernike moments operator with Sobel operator is proposed for locating the edge of the
machined workpiece, which has advantages of fast processing speed and high edge locating accuracy.
The wear amount of the grinding wheel is calculated by the image processing software, and is
compensated automatically by NC controller. Finally, this method is applied to a new type CNC curve
grinding machine MD9040. The experimental results show that the measurement and compensation
method proposed in this paper is effective, and the contour error of the workpiece with real-time
compensation is less than the feeding resolution for a compensation of 2μm.
Study on Remote Control and Fault Diagnosis for Ultrahigh Speed Grinding
Authors: Wang Wan Shan , Yu Tian Biao , Jiang Xing Yu , Yang Jian Yu
Published: March 2009

Remote control and fault diagnosis of ultrahigh speeding grinding is studied, which is based on the theory of rough set. Knowledge acquisition and reduction rule of fault diagnosis, realization method of remote control for ultrahigh speed grinding are studied, diagnosis model is established. Based on the theoretical research and ultrahigh speed grinder with a linear speed of 250 m/s, the remote control and fault diagnosis system of ultrahigh speed grinding is developed. Results of the system running show that the environment is improved, the mental pressure of workers is relieved and the efficiency is improved. At the same time, it proves that the ability to diagnosis and the accuracy of diagnosis for the ultrahigh speed grinding are improved and the time for diagnosis is shortened by applying rough set.
Technology Improvement and Parameter Optimization on the Electroplating Superhard Grinding Material
Authors: Wang Yi Wen , Liu Yi Zhi , Liu Xian Li , Wang Guo Bin , Deng Hong Cai
Published: March 2009

The superhard abrasive tools are usually made by the electroplating abrasive method. The
electroplating quality has the directly effect on the life and the performance of the superhard
abrasive tools. The electroplating technology is the major factor which influences the electroplating
qualityy. The plating pretreatment and plating nickel processes in the basic electroplating
technology were improved in this paper. The deburring, the oil removing by electrochemistry, the
anode dispose procedures and a set of new electroplating technology about incoming slot with
electronics and impact current in the plating nickel process were brought forward in this paper and
the experiment research was taken as well. The result of the experiment which used the new
technology showed that the binding power on the plating tier was enhanced, the electroplating
quality was advanced; secondly, the effects of the parameters such as the directions for the
electroplating solution, the current density, the temperature of the electroplating solution and PH
values on the electroplating quality were studied in the experiment. Finally the optimization result
was gained.
Research on Thermal Error Compensation Technology of Grinding Machine Based on Neural Networks
Authors: Guo Qian Jian , Yang Jian Guo , Qi Xiao Ni
Published: March 2009

In order to fulfill the thermal error modeling of precision abrasive machining, a neural networks model is presented through analyzing thermal error sources of the grinding machine, the structure and algorithm of the neural networks is expatiated then；And because of reasonable sample and systematical training, the accuracy of thermal error models is improved. The hardware system for thermal error compensation is proposed finally, and an experiment is accomplished on the grinding machine. The result shows thermal errors is reduced from 6μm to 1μm.
Microenvironment of Apatite-Fiber Scaffold Affects Cell Proliferation and Resulting Cell Differentiation
Authors: Honda Michiyo , Izumi Shigeki , Kanzawa Nobuyuki , Tsuchiya Takahide , Aizawa Mamoru
Published: March 2009

Appropriate culture conditions cause bone marrow stem cells to differentiate into
multilineage cells such as adipocytes, chondrocytes, and osteoblasts. One key factor that regulates
intercellular signaling and cell differentiation is the extracellular matrix microenvironment. The
composition of the extracellular matrix influences cellular functions. In the present study, we
investigated the effects of a microenvironment comprising a three-dimensional apatite-fiber scaffold
(AFS) that has two kinds of pores (micro- and macro pores) on proliferation and subsequent
differentiation of bone marrow stem cells. Morphologic observation revealed that osteoblastic cells in
the AFS were distributed primarily in the same location on the fibrous scaffold and formed bridges
within micro- and macro pores. We used molecular approaches to evaluate cell proliferation and
differentiation in detail. Reverse transcription-polymerase chain reaction (RT-PCR) analysis showed
that culturing bone marrow cells on AFS increases expression of osteocalcin (OC) mRNA compared
with culture in a dish. Furthermore, cells cultured in AFS expressed type X collagen (Col X), which is
a marker of hypertrophic cartilage. These data suggest that the three-dimensional microenvironment
of AFS facilitates cell proliferation and differentiation, and promotes endochondral ossification of
bone marrow cells.
Gene-Expression of MC3T3-E1 Osteoblast Cells Cultured on Anodized Titanium Surface and Machined Titanium Surface by Using cDNA Microarray
Authors: Park S.H. , Park J.M. , Lee H.S. , Min K.S. , Pae A.R. , Kang N.R.
Published: March 2009

One of the techniques for modifying Ti implant surface is an anodization. This method is an electrochemical one that forms rough, thick, and porous oxide films. To compare the gene expression from the cells cultured on the different implant surface, cDNA microarray have been performed. MC3T3-E1 cells were cultured on titanium disks. The control groups were cultured on the machined surfaces(MS). The experimental groups cultured on the anodized titanium surfaces(AS). Microarray assay 48 hours after culturing the cells on the machined surface and anodized surface revealed that osteoinductive molecules appeared more prominent on the anodized surface, whereas the adhesion molecules on the biomaterial were higher on the machined surface than anodized surface, which will affect the phenotype of the plated cells depending on the surface morphology.
Expression Patterns of Cell Surface Molecules on Human Bone Marrow Stromal Cells from Multi-Donors
Authors: Yoo Jeong Joon , Nam Kwang Woo , Koo Kyung Hoi , Yoon Kang Sup , Kim Hee Joong
Published: March 2009

The unique characteristics of cell surface molecules on human bone marrow stromal cells
(hBMSCs) have not been clearly elucidated. The authors characterized 19 cell surface molecules on
culture-expanded hBMSCs obtained from 10 human donors, by flow cytometry, calculated the
averages and standard deviations of the expression frequencies of individual surface molecules, and
evaluated their expression patterns with respect to donor-dependent variations. Surface molecules
expressed at frequencies of more than 80% on cells included, CD49e, CD29, CD90, CD73, CD44,
CD105, and CD146, those expressed at frequencies of 20-80% included, Stro-1, CD51, CD54,
CD31, CD106, CD163, and CD34, whereas CD49d, CD14, CD144, CD11b, and CD45 were
expressed at less than 20%. Substantial donor-dependent variations (>10% standard deviation in
expression percentage) were observed in the expressions of CD105, Stro-1, CD51, CD54, CD31,
CD106, CD163, and CD34. Our results demonstrate that CD49e, CD29, CD90, CD73, and CD44
can be used as a positive marker for hBMSCs, and that CD144, CD11b, and CD45 could be used as
a highly selective negative marker. However, the expressions of CD54, CD31, and CD106 observed
in the present study, contradicted prior reports and thus, their expressions remain controversial.
In Vivo Osteogenesis in Porous Hydroxyapatite Scaffold Processed in Hyaluronic Acid Solution
Authors: Yoshikawa Masataka , Yabuuchi T. , Tsuji N. , Shimomura Y. , Hayashi H. , Ohgushi Hajime
Published: March 2009

Porous hydroxyapatite (HA) scaffolds were processed in hyaluronic acid solution. Bone
marrow cells obtained from the bone shaft of femurs of Fischer 344 rats at 1×106/ml concentration
were seeded in pores of the scaffolds. The scaffolds were implanted in the dorsal subcutaneous
tissue of rats for 2, 4, 6 or 8 weeks. Removed HA scaffolds at 2 and 4 week after dorsal
subcutaneous implantation were histologically examined. At all experimental periods, osteocalcin in
the scaffold was immunochemically measured for the quantitative analysis of osteogenesis by bone
marrow cells in the porous HA scaffolds. Moreover, value of alkaline phosphatase (ALP) activity in
the scaffolds was measured. Osteocalcin measured in scaffolds without bone marrow cells was 1.3
ng in an average and the ALP activity was 62.2 μmol at 4 week. In hyaluronic acid processed
scaffold with bone marrow cells, quantity of osteocalcin increased from 1.6 ng at 2 week to 2.2 ng at
4 week after implantation of the scaffold. Histologically, many pores containing bone in the
scaffolds immersed in hyaluronic acid solution were detected. Significant difference of the quantity
of osteocalcin was recognized between 2 and 4 week implantation. There was no significant
difference in the quantity of osteocalcin between the scaffolds implanted for 4 and 8 weeks. Value
of ALP activity of the scaffold implanted for 4 weeks showed significant difference comparing with
that implanted for 6 and 8 weeks. From the results of this study, quantitative increase of the bone
formation in the pores of HA scaffolds would be able to observe from 6 to 8 weeks after
implantation on the scaffolds by immersion in hyaluronic acid solution