bluuebunny/crossref_metadata_2025 huggingface dataset:
First Principles Study on Ideal Strength of Cu Multi-Shell Nano-Wire
Authors: Kitamura Takayuki , Kushima Akihiro , Umeno Yoshitaka
Published: March 2009

The ideal strength of a nano-component, which is the maximum stress of the structure,
provides an insight into the mechanical behavior of minute material. We conducted tensile
simulations for cylindrical-shaped Cu nano-wires composed of an atomic chain as a core wrapped
around by shell(s) with the structure of (111) layers in an fcc crystal. The results are compared with
Cu atomic chain and sheet which are components of the nanowire. Young’s moduli and the ideal
strengths of the wires are less than a single atomic chain and a sheet. The mechanical strength of the
wire is weakened by the following three factors: (A) Change in electron arrangement caused by
combining core and shell; (B) Larger interatomic distance (inherent tensile strain) of the outer shell
introduced by the mismatch of atomic layers due to the curvature difference; (C) Mismatch between
shells due to curvature difference. Factor (A) reduces the bonding strength in the shell(s) that
occupy a greater part of the wire. 5-1 wire, which consists of a core and a shell, is weaker than the
single atomic chain and the single sheet due to (A) and (B). 10-5-1 wire, consisting of a core and
two shells, has less strength than 5-1 wire due to (C) in addition to (A) and (B).
The Pressure-Assisted Master Sintering Surface of Silicon Nitride
Authors: An Kyong Jun , Han Myung Keun
Published: March 2009

For the pressure-assisted master sintering surface (PMSS), the sintered density during hot
pressing is a unique function of the integral of a temperature function over time at a fixed pressure,
irrespective of the heating path. The present research was undertaken to develop the pressure-assisted
master sintering surface for silicon nitride known as potential material for high-temperature structural
applications due to its excellent mechanical and thermal properties. High-purity α-Si3N4 powder
(E-10 grade, Ube Industries) were mixed with 6.25% Y2O3 by alumina ball milling in ethanol for 3
hours. From the weight loss of ball mill after mixing, 1% Al2O3 was added. Consequently, SiN,
6.25% Y2O3 and 1% Al2O3 of powder mixture were prepared. After drying the resultant slurry at
100°C, the mixed powder were cold pressed at 300Mpa and made as disk of 25.4mm diameter and
2mm thickness. Then, densifications of silicon nitride were continuously recorded during heating at
two different ramping rates of 5°C/min and 10°C/min up to 1800°C at fixed pressures from 7 to 34
MPa. The pressure-assisted master sintering surface of silicon nitride was successfully constructed.
Using this surface, the final density can be predicted to about 1% accuracy for a fixed pressure and an
arbitrary temperature-time path.
Ionic Inhibition of Environental Fatigue Crack Growth in 7075-T6
Authors: Warner Jenifer S. , Kim Sang Shik , Gangloff Richard P.
Published: March 2009

The objective of this study is to quantify and understand the effectiveness of a hexavalent chrome
replacement ion to inhibit environmentally assisted fatigue crack propagation (EFCP) in high strength
aluminum alloys. Addition of molybdate (MoO4
2-) to bulk-low chloride solution effectively inhibits
EFCP in peak aged 7075, comparable to that of CrO4
2-. The effectiveness of inhibition depends strongly
on loading variables: .K, R, and frequency as explained qualitatively by mechanical instability of a
crack tip passive film that otherwise hinders production and uptake of embrittling hydrogen. The critical
loading frequency (and crack tip strain rate), below which film stability and inhibition occur, increases
with increasing inhibitor concentration, but only for low stress ratio loading, perhaps due to occluded
crack transport and reaction considerations. Molybdate could be a beneficial replacement for chromate
and a candidate for inhibitor release from a tailored coating.
A Principal Component Analysis of Acoustic Emission Signals from a Landing Gear Component
Authors: Pullin Rhys , Hensman James J. , Holford Karen M. , Worden Keith , Evans S.L.
Published: March 2009

Acoustic emission monitoring was completed on a painted aerospace grade steel landing
gear component undergoing fatigue loading until rupture. A post-test linear location analysis of the
collected signals revealed eleven groups where high activity (greater than 2000 hits) occurred
within a defined location, three of which corresponded in location to the position of fracture and
final rupture of the specimen. Feature data, such as amplitude, rise-time, energy etc. were used to
describe the identified signals in each group. A dimension reduction through principal component
analysis of the feature data of all groups was performed. Results showed that high amplitude signals
associated with four groups of signals arising from noise could be separated from the fracture
groups. However four groups not associated with noise or the known positions of the fracture
groups were not separable from the signals attributed to fractures. The paint layer of the specimen
was removed and a magnetic particle investigation was completed that showed these four groups
coincided with regions of additional fracture in the component.
Fatigue Behavior of RC Slab Retrofitted with Carbon Fiber Mesh after Different Levels of Pre-Damage
Authors: Seo Soo Yeon , Yoon Hyun Do , Park Cheol Woo
Published: March 2009

Three RC slab specimens were designed and manufactured to investigate the fatigue
behavior of RC slab retrofitted with carbon fiber mesh (CFM) and mortar. Among three slab
specimens, two slabs were pre-loaded to introduce damage prior to the fatigue loading tests. Fatigue
loading was applied to the top of slab maintaining 40% of the ultimate strength of specimen at 2Hz
loading speed. The fatigue test was terminated when the loading cycle exceeded 1,000,000 cycles.
From the test results, the effectiveness of the retrofitting using CFM was evaluated. Test result
showed that the specimens retrofitted after either severe or light damages had very similar strength
and stiffness to those of the specimens retrofitted without damage. It was found that the strength was
even slightly improved in the specimen retrofitted with CFM.
Damage Assessment of Beams Using Flexural Wave Reflection Coefficients
Authors: Shone Simon P. , Mace Brian R. , Waters Tim P.
Published: March 2009

The wave reflection coefficients of damage such as cracks, notches and slots in otherwise
uniform beams depend on frequency and on the size of the damage. Experimental results are
presented for the wave power reflection coefficients of transverse slots of various depths sawn into
a number of beam specimens. These results are compared with a conventional spring model to
estimate the depth of the slot. The method appears to work well for larger slot depths (greater than
about 30% of the thickness of the beam) and at higher frequencies, allowing their existence to be
inferred and their size to be estimated. This is due to the fact that the reflection coefficients are
larger in these regimes. For smaller slots or at low frequencies, noise and experimental errors, such
as miscalibration errors and ill-conditioning, become more significant.
Modal-Model Applications for Large Energetic Machines
Authors: Kurowski Piotr
Published: March 2009

Modal models are commonly encountered forms of dynamic characterization of
mechanical structures. They are applied in machine-condition diagnosing as well as in monitoring
processes. In research practice the most frequently applied method is Experimental Modal Analysis,
and in exploitation - Operational Modal Analysis. Difficulties associated with the EMA and OMA
have contributed to the increase of OMAX model applications, especially in case of energetic
machines.
Theoretical assumptions related with modal analysis are very strong. In reality when big and heavy
structures are considered often those assumptions are not fulfilled. In the paper such situations are
considered and practical solutions are showed.
Bayesian Approach to Condition Monitoring of PRC Bridges
Authors: Zonta Daniele , Pozzi Matteo , Zanon Paolo
Published: March 2009

This paper presents a damage detection procedure based on Bayesian analysis of data
recorded by permanent monitoring systems as applied to condition assessment of Precast Reinforced
Concrete (PRC) bridges. The concept is to assume a set of possible condition states of the structure,
including an intact condition and various combinations of damage, such as failure of strands, cover
spalling and cracking. Based on these states, a set of potential time response scenarios is evaluated
first, each described by a vector of random parameters and by a theoretical model. Given the prior
distribution of this vector, the method assigns posterior probability to each scenario as well as updated
probability distributions to each parameter. The effectiveness of this method is illustrated as applied
to a short span PRC bridge, which is currently in the design phase and will be instrumented with a
number of fiber-optic long gauge-length strain sensors. A Finite Element Model is used to simulate
the instantaneous and time-dependent behavior of the structure, while Monte Carlo simulations are
performed to numerically evaluate the evidence functions necessary for implementation of the
method. The ability of the method to recognize damage is discussed.
Near Real-Time Monitoring of Bead Area Damage in Rolling Tires Using a Rotating Wheel Model and Multi-Directional Vibration Data
Authors: Yoder Nathanael C. , Johnson Timothy J. , Adams Douglas E.
Published: March 2009

In current tire durability tests, technicians must stop tests periodically to inspect each
tire, resulting in a time consuming, expensive, and relatively subjective process. Online tire
monitoring would thus be a dramatic improvement over the current methodology. If such a system
could be extended to on-line vehicle use, it could dramatically increase safety, reduce downtime,
and lead to better fuel efficiency in commercial and passenger cars and trucks. A near real-time
system to monitor the initiation of bead area damage in rolling tires was developed using vibration
data collected from the wheel end spindle. To generate an accurate model of the forced response of
the wheel end spindle, a tire on a fixed spindle was impacted with a modal punch while the tire was
preloaded against a plate. The frequency response functions acquired from this system were then
used to develop a rotating tire model consisting of time-delayed forcing functions applied to the tire
patch at the rolling frequency; this model was used to assist in interpreting the results from the near
real-time monitoring system. The near real-time continuous monitoring system has been deployed
in a manufacturing test environment and utilizes frequency data from three mutually orthogonal
acceleration measurements. These data are combined to create a highly sensitive composite index
that identifies when the initiation of bead area damage has occurred.
Wavelet Analysis for Damage Identification in Composite Structures
Authors: Grabowska Joanna , Palacz Magdalena , Krawczuk Marek , Ostachowicz Wiesław M. , Trendafilova Irina , Manoach Emil , Cartmell Matthew P.
Published: March 2009

The main aspect of the paper is to give an answer to the question of what specific kind of
defect has actually occurred in a structure and how to distinguish between different kinds of
discontinuities. For this purpose composite rods and beams with fatigue cracks, step changes in
cross-sectional area and small changes in material properties have been investigated. The objective
of the work has been to propose a signal processing methodology based on wavelet transformation
for identification of specific discontinuity. The identification of a fatigue crack from other
discontinuities has been demonstrated. It has been also found that the proposed methodology might
be useful for precise indication of the size of the identified fatigue damage.
Bearing Fault Detection Using Higher-Order Statistics Based ARMA Model
Authors: Li Fu Cai , Ye Lin , Zhang Gui Cai , Meng Guang
Published: March 2009

Impulse response provides important information about flaws in mechanical system.
Deconvolution is one system identification technique for fault detection when signals captured from
bearings with and without flaw are both available. However effects of measurement systems and
noise are obstacles to the technique. In the present study, a model, namely autoregressive-moving
average (ARMA), is used to estimate vibration pattern of rolling element bearings for fault
detection. The frequently used ARMA estimator cannot characterize non-Gaussian noise
completely. Aimed at circumventing the inefficiency of the second-order statistics-based ARMA
estimator, higher-order statistics (HOS) was introduced to ARMA estimator, which eliminates the
effect of noise greatly and, therefore, offers more accurate estimation of the system. Furthermore,
bispectrums of the estimated HOS-based ARMA models were subsequently applied to get clearer
information. Impulse responses of signals captured from the test bearings without and with flaws
and their bispectra were compared for the purpose of fault detection. The results demonstrated the
excellent capability of this method in vibration signal processing and fault detection.
Instantaneous Identification of Bouc-Wen-Type Hysteretic Systems from Seismic Response Data
Authors: Ceravolo Rosario , Demarie Giacomo V. , Erlicher Silvano
Published: March 2009

This paper presents a technique for identification of non-linear hysteretic systems
subjected to non-stationary loading. In the numerical simulations, a Bouc-Wen model was chosen
for its ability to represent the properties of a wide class of real hysteretic systems. The parameters of
the model are computed instantaneously by approximating the internal restoring force surface
through an “ad hoc” polynomial basis. Instantaneous estimates result from time-varying spectra of
the response signals. A numerical application of interest to earthquake engineering is finally
reported.
Plastic Optical Fiber Displacement Sensor for Cracks Monitoring
Authors: Olivero Massimo , Perrone Guido , Vallan Alberto , Abrate Silvio
Published: March 2009

In the following we present a low-cost optical system for cracks evolution monitoring.
The transducer principle is based on the variation of light transmitted between two facing fibers
with their axial distance, exploiting the unique light-collecting capabilities of large-core polymer
optical fibers. The characterization shows that the working range of the transducer is up to 3.5cm,
with a resolution of 10$m and a repeatability of 5$m. With our current custom-developed control
unit, up to four transducers can be arranged to provide a multi-axial displacement sensor or to
simultaneously monitor four points for distributed sensing. A closed-loop light
modulation/detection scheme is implemented to reduce the environmental noise sensitivity. The
control unit is interfaced to a PC via USB port or via GSM/GPRS modem to automatically send
periodical reports of the measurements and to issue warnings in case of displacements above a given
threshold. Extensive tests in an environmental chamber have been carried out in order to extract
calibration curves and to compensate for day-night and summer-winter temperature fluctuations.
Damage Localization Using Levenberg-Marquardt Optimization
Authors: Parker Danny L. , Frazier William G. , Gray Mathew A.
Published: March 2009

In this paper, an optimal solution method is proposed for determining the location of
change, i.e. damage, within a perturbed system utilizing a nonlinear pseudo-second order search
algorithm based on function evaluations and gradient information. This method is applied to
damped vibrating systems and utilizes stiffness matrix sensitivities to determine the direction of
search within the estimation. The site of damage (location of change) is the solution which
minimizes the error between the predicted and measured change. A by-product of the Levenberg-
Marquardt algorithm is an estimation of the magnitude of the change within the system which
correlates to damage extent. A second-order model of a dynamic system is used, and an
approximation is developed to describe small perturbations within the system.
Control of Mesoscopic Particle Structure in Barium Titanate Nanoparticles and their Dielectric Properties
Authors: Takizawa Kayo , Hoshina Takuya , Kakemoto Hirofumi , Tsurumi Takaaki , Kuroiwa Yoshihiro , Wada Satoshi
Published: March 2009

Barium titanate (BaTiO3) fine particles were prepared using the 2-step thermal decomposition method of barium titanyl oxalate. At the 2nd step of this method, the intermediate compound (Ba2Ti2O5·CO3) was decomposed into BaTiO3 and CO2 under various degrees of vacuum pressure. As a result, the particle size of prepared BaTiO3 nanoparticles decreased with decreasing pressure. Moreover, the dielectric constants of these BaTiO3 nanoparticles were measured using the powder dielectric measurement method using slurry. The dielectric constant of BaTiO3 nanoparticles increased with decreasing pressure at the same particle size. It is considered that mesoscopic particle structure controlled by vacuum pressure is important for the dielectric properties of BaTiO3 nanoparticles.
Domain Dynamics of C-Axis Polarization in Bismuth Titanate Crystals
Authors: Kitanaka Yuuki , Noguchi Yuji , Miyayama Masaru
Published: March 2009

Polarization switching and domain dynamics in unpoled and poled crystals of bismuth
titanate by applying electric field along the crystallographic c axis were investigated through
polarization measurements and domain observations by optical microscope and piezoelectric force
microscope. Poled crystals showed a well-saturated polarization hysteresis with a remanent
polarization of 4.4 μC/cm2 and a coercive field of 4.7 kV/cm. Domain observations reveal that
lenticular domain acts as an initial nucleus during polarization switching. The sidewise motion of
the lenticular-domain walls and resultant single domain state were easily established for the poled
crystals, while the lenticular domains observed in unpoled crystals were clamped even though a
high electric field was applied to them.
Preparation and Characterization of Porous Ceramic Support
Authors: Wang Yao Ming , Xue You Xian , Shen Qiang , Zhang Lian Meng
Published: March 2009

The porous ceramic support was prepared from cordierite by adjusting the phase
composition, grain size of aggregate, additions of pore-forming material and binder. The porous
ceramic support had excellent chemical stability and relative high strength with a porosity of 48％and
pore size of 128μm. Factors that affected the properties of the support material were analyzed. The
pore size of the porous ceramic support was directly proportional to the grain size of the aggregate
around firing temperature. The strength of the support material increases with a rise in amount of the
binder and firing temperature. The porosity of the support material increases while the strength
decreases with a rise in amount of the pore-forming agent.
Fabrication of Ceramic-Metal Composites by Melt Infiltration of Moso-Bamboo-Derived Porous SiC
Authors: Lin Yung Jen , Lin Shi Yi
Published: March 2009

Copper and 2024 aluminum alloy were melt-infiltrated into porous β-SiC to form SiC/Cu and SiC/Al composites. The porous β-SiC was prepared using Moso bamboo as the bio-template and had structural characteristics of bamboo. The Cu infiltration occurred as low as 1100°C and became significant at 1200°C. After infiltration at 1300°C for 4 h, there was still ~5 % of residual porosity. For the composites with low degree of metal infiltration, the samples fractured like the bamboo-structured porous SiC. For the composites with high degree of infiltration, the sample behaved like monolithic copper. In the infiltration of Al alloy, infiltration occurred at 900°C. Higher Infiltration temperatures would result in significant formation of Al4C3, which gradually decomposed in air.
Consolidation and Properties of Tungsten Carbide Target with Low Cobalt Content by Hot-Press Sintering
Authors: Shao Gang Qin , Xiong Z. , Wang T.G. , Shi Xiao Liang , Duan Xing Long
Published: March 2009

Tungsten carbide (WC) targets with low cobalt (Co) content (0.1 - 0.2 wt.%) were prepared by hot-press sintering at 1700°C for 60 minutes in argon, from element starting powders of tungsten, cobalt and carbon. Results show that the as-fabricated targets yield relatively high relative density above 99% and high HRA above 92. WC with low Co content is formed easily than pure WC. The hot-press sintering process, while element starting powders are used, is an in-situ reaction technique for accelerating the WC’s diffusion rate to obtain a dense sintered body.
Metal-Ceramic Composites Prepared through In Situ Decomposition of Transition Metal Nitrides
Authors: Jin Xi Hai , Gao Lian , Sun Jing
Published: March 2009

Co/ZnO and Ni/Al2O3 composites were prepared by in-situ decomposition of CoNx and NiNx during sintering, using CoNx/ZnO and NiNx/Al2O3 mixtures synthesized through an in-situ nitridation method as the starting powders. It was found that these composites showed a very uniform microstructure with metal particles homogeneously distributed among matrix grains. The microstructure and properties were tentatively studied.
Plastic Deformation of Silicon Nitride Nano-Ceramics
Authors: Nishimura Toshiyuki , Xu Xin , Hirosaki Naoto , Xie Rong Jun , Tanaka Hidehiko
Published: March 2009

A commercial silicon nitride powder with sintering additives was ground by high-energy
milling to reduce particle size. Nanometer sized powder was obtained. The powder was densified for
short time by spark plasma sintering to prevent grain growth. Nanometer-grained Si3N4 ceramics
were obtained. Plastic deformation of the Si3N4 nano-ceramics has been studied in compression over
a wide range of strain rates and temperatures. The experimental results revealed that a transition in
stress exponent, n, at each temperature. The n value decreased from ~ 2 to ~ 1 with increasing applied
stress. Activation energy was also different for the two regions, decreasing from 858.2 kJ/mol in the
n ~ 2 region to 571.8 kJ/mol in the n ~ 1 region. Effect of sintering additives on plastic deformation
was also discussed.
Synthesis and Microstructural Evaluation of SiC-AlN Composites
Authors: Shirouzu Keita , Nonaka Yuki , Hotta Mikinori , Enomoto Naoya , Hojo Junichi
Published: March 2009

High-density SiC-AlN composites were fabricated from powder mixtures (50:50 in mol) in
1900oC-2100oC temperature range by SPS process. SiC(0.3μm or 0.03μm) and AlN(1.1μm) were used as
starting materials. The density of composite increased with increasing firing temperature. From the
identification of crystal phase and the change of lattice constant, mixed phases of 3C(β-SiC)ss and
2H(α-SiC/AlN)ss were found at 1900oC and 2000oC, and only 2Hss was found at 2100oC. The OM and
EPMA observation indicated that SiC-rich regions (size:10-50μm) existed throughout SiC(0.3μm)-AlN
composite because of aggregation of SiC powder. In SiC(0.03μm)-AlN composite, on the other hand,
SiC-rich regions (size:submicron) and AlN-rich regions (size: approximately 1μm) existed on a
microscopic level at 1900oC, whereras, it was confirmed from EPMA and SEM observation that
homogeneous 2H(ss) formed with large grain-growth at 2100oC. The microstructure of
SiC(0.03μm)-AlN composite at 2000oC was analyzed to investigate more detailed compositional
variation of solid solution. SEM-EDS observation indicated that 3C(ss), SiC-rich 2H(ss) and AlN-rich
2H(ss) existed in SiC(0.03μm)-AlN composite at 2000oC.
Bonding and Integration of Silicon Carbide Based Materials for Multifunctional Applications
Authors: Singh Mrityunjay , Halbig Michael C.
Published: March 2009

Robust bonding and integration technologies are critically needed for the successful
implementation of silicon carbide based components and systems in a wide variety of aerospace and
ground based applications. These technologies include bonding of silicon carbide to silicon carbide as
well as silicon carbide to metallic systems. A diffusion bonding based approach has been utilized for
joining of silicon carbide (SiC) to silicon carbide sub-elements for a micro-electro-mechanical
systems lean direct injector (MEMS LDI) application. The objective is to join SiC sub-elements to
from a leak-free injector that has complex internal passages for the flow and mixing of fuel and air. A
previous bonding approach relied upon silica glass-based interlayers that were non-uniform and not
leak free. In the newly developed joining approach, titanium foils and physically vapor deposited
titanium coatings were used to form diffusion bonds between SiC materials using hot pressing.
Microscopy results show the formation of well adhered diffusion bonds. Initial tests show that the
bond strength is much higher than required for the component system. Benefits of the joining
technology are fabrication of leak free joints with high temperature and mechanical capability.
Fabrication of Two Dimensional Silicon Carbide Fiber-Reinforced Silicon Carbide Composite by Electrophoretic Deposition and Hot-Pressing
Authors: Yoshida Katsumi , Matsumoto Hideki , Imai Masamitsu , Hashimoto Kazuaki , Toda Yoshitomo , Yano Toyohiko
Published: March 2009

In this study, Tyranno SA fiber cloth was coated with carbon black and SiC powder containing sintering aids by means of electrophoretic deposition method, and SiC/SiC composites with three different fiber volume fractions were fabricated using the Tyranno SA cloth by hot-pressing at 1700oC. The sufficient formation of the SiC matrix between each fiber could be observed. The composite fractured in non-brittle manner, and bending strength decreased with increasing fiber volume fraction. The crack propagation and fracture behavior depended on the fiber volume fraction. These differences in bending strength and fracture behavior would be caused by the difference in the interfacial bonding between fiber cloth and the matrix.
Influence of Nano-Silica on Microstructure and Mechanical Properties of SiO2/BN Ceramics
Authors: Zhou Li Zhong , Jia De Chang
Published: March 2009

In this paper, nano-silica particles were incorporated to a fused silica-boron nitride dual
phase ceramics originally using micrometer sized particles as starting powders. Effects of
nano-silica content on density, sintering behavior, mechanical properties and microstructure of the
dual phase ceramics were investigated. It was found that with the addition of nano-silica particles,
the density and mechanical properties of the dual phase ceramics increased. Flexural strength and
fracture toughness of them attained to 51.4MPa and 0.8MPa·m1/2, respectively. The increased
density and spatial network structure of fused silica attribute to the improvement of the mechanical
properties of the dual phase ceramics.
Coating Influence on Residual Stress in Laser Shock Processing
Authors: Xu Y.Y. , Ren Xu Dong , Zhang Yong Kang , Zhou Jian Zhong , Zhang Xing Quan
Published: March 2009

Laser shock processing is an important surface treatment that induces compressive residual
stress to components, where the coating plays an important role. This paper deduce a general formula
of the optimum thickness of coating according to the law of energy conservation and analysis the
influence of coating on residual stress of the titanium alloy in laser shock processing. Titanium alloy
with black paint, silica acid black paint and without coating were shocked by laser system respectively.
It was found that coating could increase shock pressure amplitude and laser density absorption.
Compressive residual stresses at the surface of the sample with the black paint and silica acid black
paint are about -212.2MPa and -264.2MPa respectively, while the surface stress on the uncoated
specimen is very high tensile stress. The bare surface due to melting and vaporization, leads to a very
rough surface. The depth of induced compressive stress could reduce stress corrosion cracking in
titanium alloy and improve fatigue lifetime.
Fuzzy Method to Determine Probability Distribution Type of Fatigue Crack Data
Authors: Huang Hong Zhong , Du Li , Miao Qiang , Wang Zong Lai , Ma Q.
Published: March 2009

Since the number of fatigue crack propagation data is related to cost and time and the crack
propagation data are generally finite, adopting median rank or average rank as the probability value of
a test datum will result in significant error. On the basis of analyzing disadvantages of traditional
methods to identify distribution functions, which begin with overall fitting effect, this paper proposed
a method by applying numerical simulation and fuzzy linear regression. It can be used to determine
the distribution function of crack propagation data. Through fuzzy linear regression, the result that
crack propagation size under certain load cycles are in logarithmic normal distribution can be
acquired. In the same way, the number of load cycles is also in logarithmic normal distribution when
the crack propagates to a certain size.
Residual Stress Characteristics of Plasma Sprayed CoNiCrAlY Coatings by X-Ray Diffraction
Authors: Waki Hiroyuki , Kobayashi Akira
Published: March 2009

Plasma sprayed CoNiCrAlY coating can prevent oxidation and corrosion of turbine blades
in a gas turbine plant. Cracking and delamination of coatings are affected by the residual stresses in
the coatings. In this study, the arising mechanism of residual stress in the plasma sprayed coating was
discussed. The residual stresses in CoNiCrAlY coatings were measured by X-ray diffraction method.
The coatings were deposited by either low pressure plasma spraying (LPPS) or atmospheric plasma
spraying (APS). Each elastic constant which was used for determining the X-ray stress constant was
mechanically measured by a bending test. Two kinds of substrates were prepared for each coating in
order to examine the effect of thermal expansion coefficient of a substrate. Results were as follows.
The residual stresses of the coatings on steel substrates were tensile. On the other hand, the residual
stresses on stainless substrates were lower than those on steel substrates. Arising mechanism of the
residual stresses can be explained by both the linear expansion coefficient and the range of changing
temperature. It was also found that the absolute residual stresses were affected by the spraying powder
size and increased with a decrease of the spraying powder size. It was principally caused by the
difference in the elastic constants.
Failure Analysis of Outer Swirls in the Fuel Nozzle
Authors: Tian Ji Feng , Yao Ge , Zang Qi Shan
Published: March 2009

Failure analysis of 4 swirls in the fuel nozzle of a gas turbine was made by macroscopic
and microscopic examination, and verified test were conducted. The result showed that the swirls in
the fuel nozzle subjected thermal fatigue and failed in different manner for different reasons.
Effect of Si and Ti Coating on Interface Bonding between Diamond and Fe-Based Metal Bond
Authors: Lu Jing , Wang Yan Hui , Zang Jian Bing , Shan Shu Xian
Published: March 2009

Fe-based metal bond has been widely used in fabricating diamond tools recently since the production cost could be greatly reduced for the low price of iron. However, graphitizing elements such as Fe, Co and Ni in the matrix catalyze the transformation of diamond to graphite during high temperature sintering process, which significantly decreases the tool’s efficiency and lifetime. In this paper, Si and Ti coating were coated on diamond grits by quasi atomic layer deposition (QALD) and vacuum slow vapor deposition (VSVD) separately not only to protect diamond from erosion but also to promote the adhesion between diamond grits and the bond. Three-point bending experiment was taken to measure the bending strength of Fe-Cu-Sn-Ni based metal bond diamond blade. In comparison with uncoated diamond blade, the bending strength of coated diamond blade improves dramatically. The theoretic calculation shows that the interface bonding strength between diamond and the metal bond increases by 181.68MPa owing to the Si coating. The effect of Si and Ti coating on interface bonding between diamond and the bond under different sintering temperatures was also illuminated.
Monitoring and Compensation of Thermal Error of Profile Grinding Spindle
Authors: Xu Li Ming , Shi Lun , Zhao Xiao Ming , Hu De Jin
Published: March 2009

Spindle thermal deformation is the main error source of many precision profile grinders.
In this paper, the relationship between spindle temperature and either radial or axial thermal
deformation is studied based on experiments. The placement and amount of temperature sensors are
optimized. Then a kind of thermal error modeling method based on support vector machine is
presented and applied in the modeling of thermal error of profile grinding. The result shows the
model is robust and the on-line accurate prediction of grinding thermal error is realized based on
monitoring of temperature rise of spindle. Finally, the error compensation strategy is discussed for
further application of thermal error modeling.
Optimize Parameters of Floating Polishing with Tri-Polishing-Disk
Authors: Xu Xiao Cun , Yuan Zhe Jun , Lin Bing
Published: March 2009

During the transferring process of the large die surfaces, there are extensive needs of die
surface polishing. Since almost large die surfaces are free-form surfaces, currently, these are almost
manually implemented. In order to overcome this barrier, base on design a floating polisher, this paper
focuses on polishing rule of floating three polishing disks and the optimization of the associated
polishing process parameters. In order to enhance the polisher performance, affecting factors of
polishing process, including the rotation speed of polishing discs, normal acting force on polishing
disc, loci of polishing disc movement, feeding rate of polishing disc, grit of abrasive particles, and
inclined angle of the acting force on disc, are synchronized and analyzed versus roughness of polished
surfaces. Then, using the parameter design plans and conducts tests regarding these affecting factors.
Finally, the floating polishing process parameters are optimized based on the test results. These
optimized results are used as operating guides for applications of the floating die polisher.
Experimental Research on Small Holes by Electrical Discharge Machining Combined with Ultrasonic Vibration and Assisted Inwall Polish with the Ultrasonic Vibrating
Authors: Cao Ming Rang , Yang Shi Chun , Li Wen Hui , Yang Sheng Qiang
Published: March 2009

The EDM can machined some superhard conducting material that cannot be handled by the traditional method, such as carbide alloy, tool steel and engineering materials etc., however, it is also accompanied with slow material removal rate(MRR) and poor surface quality (surface roughness). For some fine machining having rigorous criterion on size and surface roughness, the EDM cannot meet the demand. Some researches indicate that the MRR of small hole by electrical discharge machining combined with ultrasonic vibration (UEDM) can increase in certain range, but the surface quality is still poor. Although there are lots of the researches on the UEDM, some debates on machining mechanism and applied scope existed, and technology of UEDM needs the further study. After small hole machined by the UEDM, it is polished by ultrasonic vibrating. Two steps are includes in this technology. In the first place, on a high velocity electro discharge small hole machine with high-pressure dielectric liquid and hollow electrode, a transducer and horn are attached between the spindle and the electrode. The ultrasonic vibration of the tool electrode is implemented by connecting the horn and the tool electrode together with a chucking appliance. The second, after the small hole is complete, with the same machine tool and tool electrode the process of polishing the inwall of the small hole is carried out by accompanying the ultrasonic vibration, revolution and feed of the tool electrode with the abrasive material. In the experiments, the reference point for UEDM is found and the new theory is proposed to explain the increase of the MRR and the decrease of the surface roughness value .The polish with the ultrasonic vibration can improve further the surface roughness. The ultrasonic vibrating polish after the hole by UEDM is an economical and effective technology, which realizes machining of two procedures in one machine tool. So the process for changing machine tool and tool is not needed any more and the efficiency is further improved.
Nonlinearity Analysis and Wavelet Package Transform of Measured Chatter Vibrations in Grinding Process
Authors: Han Qing Kai , Wen Bang Chun
Published: March 2009

In grinding process, chatter vibrations known as self-excited vibrations, become
increasingly problematic and must be avoided. Firstly, experimental measurements of chatter
vibrations in a numerical control (NC) grinding machine tool are introduced for the case of a special
alloy workpiece being carried on. Then, frequency spectra of chatter vibrations are analyzed. The
wavelet package transform technique is used to describe original chatter signals in the term of scaled
energy of frequency bands. At last, fractal dimensions of the reconstructed signals in consecutive
frequency bands of chatter vibrations are calculated. These results are helpful for understanding of the
nonlinearity of chatter vibrations.
The Characteristic of Organic Bond Grinding Wheel
Authors: Chen Mei Wei , Yuan Ju Long , Yang Yi , Yu Dong Qiang
Published: March 2009

The bond in a grinding wheel cements the abrasive grains together, Among other factors,
the bond plays a predominant part in the grinding wheel performances and on the quality of
grinding results. This paper presents a literature review on organic bond grinding wheels. It
discusses the characteristic of the bond and the grinding performances of the two mainly types of
organic bond [1] grinding wheels: the resin bond grinding wheel and the soft-elastic grinding wheel.
This paper provide a conclusion of the studying state of organic grinding wheel, which new
studying can draw lesson from.
Influence of Phase Composition on Degradation and Resorption of Biphasic Calcium Phosphate Ceramics
Authors: Mayr Helmar , Schlüfter Susanne , Detsch Rainer , Ziegler Günter
Published: March 2009

In this study the degradation behaviour of pure hydroxyapatite (HA), pure tricalcium
phosphate (β-TCP) and four biphasic calcium phosphate ceramics was studied to gain information
about the influence of the phase composition on this property with the aim to tailor individually
adapted bone substitute materials. The chemical dissolution of each ceramic composition was
measured by its release of calcium ions into a buffered solution. With decreasing HA content in the
ceramics the degradation rate increased. Cell experiments were carried out with stimulated
osteoclast-like RAW 264.7 cells. Using biochemical, genetic and microscopic analysis, the
differentiation of the cells on the ceramic samples was studied. The monocytic precursor cells
differentiated into osteoclast-like cells on all ceramics. The strongest cell differentiation into
osteoclast-like cells was found on ceramics with HA/β-TCP ratios of 80/20, 60/40 and 40/60. Cells
on these ceramics had many nuclei and the largest cell size. As a result of resorption, lacunas were
found on all ceramics except β-TCP. All these experimental results proved the influence of the
phase composition on degradation and resorption of calcium phosphate ceramics. Biphasic calcium
phosphate ceramics with HA/β-TCP ratios of 80/20 and 60/40 exhibited the most promising
properties to serve as synthetic bone substitute materials because for integration in the physiological
bone remodeling process the implanted bone substitute materials should have optimized dissolution
and resorption properties.
Cytotoxicity Analysis of Apatites Modified with Divalent Metals
Authors: Lima Ingried Russoni , Santos Silvia R. A. , Santiago D.L. , Rossi Antonella M. , Granjeiro José Mauro
Published: March 2009

Hydroxyapatite (HA) and apatite based biomaterials are important for bone replacement. Different apatites could be produced by substituting calcium, phosphate or hydroxyl groups, resulting in new materials with different physical, chemical and biological properties. In this work we investigate the biological compatibility of apatites modified by divalent cations in cultured mammalian cells using Balb/c 3T3 fibroblasts cell line. Modified apatites, Ca9.5M0.5(PO4)6(OH)2 (M=Fe, Zn, Cu, Co, Sr, V e Pb) and Ca10(VO4)6(OH)2 were produced and characterized by FTIR, XRD and XRF. Extracts of each metal-modified apatites (0.1mg/mL of Dulbeco Modified Eagle Medium – DMEM without serum) were obtained. Cells (3x104) were exposed for 24 h/37C to the pure extract (100%). Afterwards, the number of viable cells was determined in a hemocitometer. The number of viable cells in the absence of any extract was taking as 100%. SHA didn’t present any toxicity while phenol killed 82% of the cells. In the presence of pure extract of Fe-HA or Sr- HA an increase of 70% and 20%, respectively, in the number of relative cells was observed. On the other hand, the number of residual cells after treatment with the pure extract of Pb+2, Zn+2, Co+2, and (VO4)3- was73, 65, 48, and 21%, respectively. In conclusion, cells response was strongly dependent on the metal that substitutes calcium or phosphate. Further studies are required to better understand the biological effect of these substitutions.
In Vitro Studies of Cell Growth on Three Differently Fabricated Hydroxyapatite Ceramic Scaffolds for Bone Tissue Engineering
Authors: Detsch Rainer , Uhl Franzika , Deisinger Ulrike , Ziegler Günter
Published: March 2009

The aim of this study is to analyse the influence of differently fabricated HA-scaffolds on
bone marrow stromal cells. Therefore, three methods were used (a polyurethane (PU)-replica
technique, the dispense-plotting and a negative mould technique) to produce porous hydroxyapatite
(HA) ceramics. The different HA-scaffolds were then cultivated with an osteoblastic precursor cell
line. In our study, highest cell proliferation and differentiation was achieved by using (PU)-replica
technique. However, this study shows also that all three types of scaffolds are suitable for tissue
engineering applications and as bone substitute material. The knowledge about the influence of pore
size and geometry on the cell behaviour will help to tailor scaffolds, by different 3D fabrication
methods, for the needs of tissue engineering laboratories or patients.
Effect of Hydroxyapatite and Zinc-Containing Hydroxyapatite on Osseous Repair of Critical Size Defect in the Rat Calvaria
Authors: Calasans-Maia Monica , Fernandes G.V.O. , Rossi Antonella M. , Dias Eliane Pedra , Almeida G.D.S. , Mitri F.F. , Granjeiro José Mauro
Published: March 2009

Hydroxyapatite (HA), widely used as bone graft, can be modified by the incorporation of
bivalent cations (Mg2+ and Zn2+) and its gradual release could favor the bone repair. The purpose of
this research was to evaluate the effect of the HA and zinc-containing hydroxyapatite (Zn-HA) in
the bone repair in rat calvaria in comparison to autogenous bone. Critical size defect in the calvaria
was filled with the graft material and the samples were harvested at the 30, 90 and 180 days. The
light microcopy observations showed the biocompatibility of the graft materials. In the Zn-HA
group the area of neoformed bone was larger than in the HA group, but smaller than in the
autograft. A fibrous connective tissue was more evident around HA granules. It could be conclude
that the presence of zinc ions in HA crystal accelerated the osteogenesis and increased the area of
newly formed bone in relation to HA.
Biocompatibility Evaluation of Porous Si-Containing Hydroxyapatite Derived from Coral
Authors: Kim Soo Ryong , Kim Y. , Kwon W.T. , Kim H.S. , Choi Y.M. , Kim Hae Jung , Ha S.M.
Published: March 2009

A porous silicon-containing hydroxyapatite has been prepared using natural coral as a calcium source to obtain a biomaterial having an improved biocompatibility. From the XRD analysis, it was confirmed that the single-phase hydroxyapatite containing silicon has formed without revealing the presence of extra phases related to silicon dioxide or other calcium phosphate species. Silicon content is ranged from 0.5wt% to 1wt% by weight. The porous silicon-containing hydroxyapatite blocks were inserted into the 5mm diameter of drill holes made through the lateral femoral condyles of New Zealand white rabbits. The new bony formation did not begin after 1 week. At 3 week, bony ongrowth to the inserted porous silicon-containing hydroxyapatite block could be found, and the new bone surrounded the inserted block entirely after 24weeks. Based on in-vivo test, Si-containing porous hydroxyapatite derived from coral possesses high biodegradability and can be considered a useful material for bone implants.
Microstructural Observation of Calcium-Deficient Single Crystal Apatite Fibers and Phase Changes during Heating
Authors: Taki A. , Yoshimura Hideyuki , Aizawa Mamoru
Published: March 2009

Three types of calcium-deficient apatite fibers (Ca-def AF) were synthesized by a
homogeneous precipitation method using starting solution with Ca/P ratios of 1.00, 1.50 and 1.67,
and then the resulting fibers were characterized by XRD, FT-IR and SEM. Especially, the
microstructure including strain and defect of individual Ca-def AF was examined by transmission
electron microscopy (TEM). All the resulting Ca-def AFs had a single phase of apatite, and
contained carbonate ions. These fibers were of single crystal, and highly strained. However, when
Ca-def AFs were heated to higher than 800 °C, they changed to HAp and TCP biphases. The
content of the carbonate group in the Ca-def AFs decreased with heating temperature.
The Role of Si Substitution into Hydroxyapatite Coatings
Authors: Solla Eugenio Luís , Malz Frank , González Pio , Serra Julia , Jaeger Christian , León Betty
Published: March 2009

Silicon substituted Hydroxyapatite coatings were prepared by Pulsed Laser Deposition
from targets made of mixtures of Hydroxyapatite with Si powder at different concentrations. The
properties of the Si-HA coatings with several degrees of Si substitution were analyzed by different
techniques such as FTIR, XRD, XPS and solid-state NMR. It was found that the Si incorporation
causes an amorphization of the structure together with a loss of carbonate groups. Furthermore, the
Si atoms are incorporated in the form of SiO4
4- groups, and H(PO4)2- appears as the predominant
phosphate group.
Effect of CeO2 Addition on In Vitro Bioactivity Properties of K-Mica-Fluorapatite Based Glass Ceramics
Authors: Goller Gultekin , Akin Ipek
Published: March 2009

The aim of this study is to investigate the crystallization behavior and in-vitro bioactivity
character of glass ceramics having 3:7 weight ratio of fluorapatite (Ca10(PO4)6F2) to potassium mica
(K2Mg3AlSi3O10F2) as a function of cerium oxide addition, and compare the morphology of
hydroxycarbonate apatite (HCA) layer formation depending on cerium oxide addition.