bluuebunny/crossref_metadata_2025 huggingface dataset:
Kinetic Investigation of the Curing and Pyrolysis Procedures Used for the Preparation of Polymer-Derived Boron Nitride Fibres
Authors: Bernard Samuel , Fiaty Koffi , Cornu David , Miele Philippe
Published: March 2009

The kinetic investigation of the solid-state decomposition of a typical melt-spinnable
poly[B-(methylamino)borazine] into boron nitride fibers was carried out at various heating rates. It
was shown that the two-step weight loss associated with the polymer-to-ceramic conversion is
governed by two major diffusion-type transport mechanisms which are independent of the applied
heating schedule. The application of the Kissinger and Friedman methods to dynamic TG data
allowed us to measure the Ea and lnA values which are seen to increase with the extent of the
ceramic conversion from region one (Ea=46.3kJ/mol, lnA=3.85; Friedman method) in going to
region two (Ea=122.6J/mol, lnA=12.18; Friedman method). Kissinger and Friedman results are in
good agreement. It was shown that the cross-linking process of the polymer is mainly governed by a
poorly energetic mechanism indicating the occurrence of simple reactions, whereas the
mineralization and ceramization steps are majoritarly represented by a highly energetic mechanism
suggesting the occurrence of complex and multi-step mechanisms.
Sr2+ - Mn4+ Doped SiAION Ceramics
Authors: Akin B. , Kushan S.R. , Mandal Hasan
Published: March 2009

In the present work, multi-cation doped (Sr2+-Mn4+) SiAlON ceramics were investigated.
The mixture was sintered at in a gas pressure sintering furnace (GPS). XRD results showed that
sintered samples were composed of β and α-SiAlON phases and this result is also confirmed by
back scattered SEM images. EDX analysis of the individual α-SiAlON grains showed that Mn can
incorporate into the α-SiAlON structure when it is codoped with Sr.
Phase Separation in Sol-Gel Systems of Organic-Inorganic Hybrids
Authors: Nakanishi Kazuki , Kanamori Kazuyoshi
Published: March 2009

Organic-inorganic hybrid monoliths with well-defined macropores and/or mesopores have
been synthesized by a sol-gel process accompanied by polymerization-induced phase separation.
Using aklyltrialkoxysilanes and alkylene-bridged alkoxysilanes, two different categories of
organo-siloxane networks have been characterized in view of macroporoisity based on phase
separation as well as mesoporosity based on supramolecular templating by surfactants. The
alkyl-terminated polysiloxane network exhibited substantial surface hydrophobicity together with the
mechanical flexibility. On the other hand, the alkylene-bridged network behaved much more
similarly to those prepared from tetraalkoxysilanes with regard to surface hydrophilicity, mechanical
rigidness and mesopore-forming ability. Supramolecular templating of mesopores embedded in the
gel skeletons comprising well-defined macroporous network has proven to give wide variety of
hierarchically designed macro-mesoporous organic-inorganic hybrid materials.
Preparation of Synthetic Cordierite by Solide-State-Reaction with Addition of Dolomite
Authors: Setina Janina
Published: March 2009

Cordierite was obtained from the mixture of aluminum hydroxide, sand, different
magnesium compounds by a solid-state reaction method. The effect of dolomite doping on
phase-transformation kinetics and microstructure has been investigated during thermal
treatment by keeping a stoichiometric cordierite compound.
Adding of dolomite has been used as a flux for preparation of a cordierite precursor by a
coprecipitation process.
Subsequently, DTA and XRD analyses were conducted to identify the phases formed in
the sintered products. Morphological changes of the ground mixtures and sintered product
were observed using SEM.
The crystallization process of metastable quartz like μ-cordierite can be obtained at
1250…13000C. In this range of temperature form other compounds, such as spinel, quartz.
Increase of sintering temperature and prolonged holding times promote the formation of only
one phase – indialite or α-cordierite, the hexagonal form of cordierite.
Experimental observation shows two steps in the solid-state reaction. First step – formation
of volatiles compounds and pores, second – formation and growing of crystalline phases.
Evolution of CO, CO2 and H2O that occurred during the thermal treatment of compositions
is very important fact in the nucleation process. The intensity of crystallization depends on
the gas volume and amount of pore in the sample. The experiments indicated that the intrinsic
concentration of volatiles like CO, CO2, H2O influence the appearance of the cordierite phase.
SEM photographs sowed that crystallization of cordierite start on the surface of pore.
Growth of α-cordierite inside of pores is considerably affected by the time of thermal
treatment and amount of adding of dolomite. A remarkable change in peak intensity of XRD
patterns of the compositions was observed.
Up to 20 wt. % addition of dolomite to the precursor allowed the fabrication of synthetic
cordierite at lower temperature.
New Porous Visible Light Active Photocatalysts of MOx-Titanate (M = Cr, Ni) Nanohybrids
Authors: Hwang S.J. , Kim T.W.
Published: March 2009

We have synthesized for the first time efficient visible light active photocatalysts of porous
MOx-Ti1.83O4 (M = Ni, Cr) heterostructure through an exfoliation-restacking route. XRD, SEM, TEM,
and XAS results reveal that the titanate nanosheets and the nanosized metal oxide particles are well
ordered in layer-by-layer way. N2 adsorption-desorption isotherm and diffuse UV-vis spectroscopic
analyses demonstrate that the present nanohybrids have a large surface area (~190-240 m2/g) and a
narrow bandgap (~1.6-2.4 eV), which are ascribable to the formation of porous structure and a
coupling of the wide bandgap titanate and the narrow bandgap metal oxide species, respectively.
These nanohybrids show an enhanced photocatalytic activity to effectively decompose organic
compounds under the irradiation of visible light. The present results highlight that the
exfoliation-restacking route can provide a very powerful way of developing novel heterostructured
materials with efficient visible light driven photocatalytic activity.
In Situ and Ex Situ Characterization of PFSA-Inorganic Inclusion Composites for Medium Temperature PEM Fuel Cells
Authors: Bauer Felix , Müller Achim , Wojtkowiak Anna , Willert-Porada Monika
Published: March 2009

It is known, that by addition of zirconium layered phosphate (ZP) to perfluorinated
sulfonic acid ionomers (PFSA), the proton conductivity of the composite decreases, but the high
temperature stability and electrical efficiency increases as compared to the unmodified PFSA
membrane. In order to clarify this finding, mechanical properties and conductivity of a
commercially available PFSA ionomer (Nafion®117), PFSA-ZP and PFSA-calcium phosphate (CP)
composites were examined ex-situ and in-situ under conditions similar to fuel cell application. The
results indicate a strong columbic interaction between the organic and inorganic ZP phase, which at
the same time increases the stiffness and Tg by ionic cross-linking and decreases conductivity. The
interaction is more pronounced at low water activity. A threshold of about three water molecules
per sulfonic acid group was identified, above which a significant increase in proton conductivity is
achieved and, concomitantly, most of the mechanical stiffening effect has vanished. CP as inorganic
additive, however, has a tendency to be washed out of the ionomer, most probably due to the high
acidity of Nafion®.
Dielectric Properties of Spark-Plasma-Sintered Strontium Niobates
Authors: Suyama Yoko , Ichii Hiroshi , Takeuchi Tomonari
Published: March 2009

We have successfully prepared dense (Sr,Ba)2Nb2O7 ceramics consisting of fine
microstructures by the combination of using double metal alkoxide as the precursor for synthesis of
strontium barium niobates and applying the spark-plasma-sintering processes. Phase-pure
orthorhombic (Sr1-xBax)2Nb2O7 was obtained in the range of 0.8 < x < 1. The measured permittivity
showed higher values compared with those of the conventionally sintered ceramics, due probably to
its higher density and fine microstructures.
Shock Compression of Powders by Two-Stage Gasdynamic Gun
Authors: Zanotti C. , Riva G. , Giuliani P. , Daminelli G. , Reggiori A.
Published: March 2009

Powder consolidation using a shock compression apparatus is a potential method for the
processing of bulk materials. Two-stage gasdynamic guns take advantage of light gases properties
to accelerate projectiles to hypervelocity. The prototype developed at the CNR-IENI labs was
modified in order to densify powders in very short times (1-100 μs). Powder compaction can be
achieved either by the generation of a pressure pulse (10-30 104 bar) or by direct impact on the
powder sample of a high speed projectile (0.5 - 2 Km/s). A numerical code, to simulate the
gasdynamic gun behavior, has been written and, depending on the densification method (pressure
pulse or impact) can be used to calculate the pressure and temperature histories in the densification
stage or the pellet velocity, momentum and kinetic energy just before the impact. Preliminary
experimental tests indicate the capability of this apparatus to densify different kind of precompacted
powders.
Microstructural Design for Attaining High-Strain-Rate Superplasticity in Oxide Materials
Authors: Hiraga Keijiro , Kim Byung Nam , Morita Koji , Suzuki Tohru , Sakka Yoshio
Published: March 2009

Factors limiting the strain rate of superplastic deformation in oxide ceramics are discussed
from existing knowledge about the mechanisms of high-temperature plastic deformation and
intergranular cavitation. The discussion leads to the following guide: simultaneously controlling the
initial grain size, diffusivity, dynamic grain growth, homogeneity of microstructure and the number of
residual defects is essential to attain high-strain-rate superplasticity. Along this guide, high-strain-rate
superplasticity (HSRS) is attainable in some oxides consisting of tetragonal zirconia, α-alumina and a
spinel phase: tensile ductility reached 300-2500% at a strain rate of 0.01-1.0 s-1. Post-deformation
microstructure indicates that some secondary phases may suppress cavitation damage and thereby
enhance HSRS. The guide is also essential to lower the limit of deformation temperature for a given
strain rate. In monolithic tetragonal zirconia, grain-size refinement combined with doping of aliovalnt
cations such as Mg2+, Ti4+ and Al3+ led to HSRS at 1350 °C.
Self-Propagating High-Temperature Synthesis, Dynamic/Quasi-Static Densification, and Superplasticity of Ceramics
Authors: Gordopolov Yury A. , Zaripov Nail G. , Gordopolova Larissa V.
Published: March 2009

The microstructure evolution during high-temperature deformation at (a) high strain rates
and low strains (dynamic densification, shock compression) and (b) low strain rates and high strains
(quasi-static densification, superplastic regime) was studied. Off-stoichiometric titanium carbide
was selected as a testing system. The results demonstrate that high-temperature deformation in a
broad range of strain rates provides means for controlling the microstructure of titanium carbide. By
varying deformation conditions, one can obtain materials differing in microstructure and chemical
composition, in particular, with equilibrium and nonequilibrium microstructures. Accordingly, the
physicochemical properties of such materials are also different.
Fabrication and Morphological Stability of Aluminium Nanostructures En Route to Nanopatterned Sapphire
Authors: Biser Jeffrey M. , Perkins Jason T. , Li Hong Wei , Chan Helen M. , Vinci Richard P.
Published: March 2009

It has recently been demonstrated that it is possible to produce a pristine surface layer on
a lapped sapphire substrate by depositing a thin film of aluminum and subjecting it to an appropriate
thermal treatment. This process also shows promise for the fabrication of nanopatterned sapphire
by pre-patterning the aluminum metal prior to thermal conversion to sapphire. We have explored
two distinct patterning processes: a dual layer photoresist e-beam lithography technique for
fabricating arbitrarily shaped aluminum structures, and a novel, non-conventional mask-liftoff
method involving nanoporous anodized aluminum oxide, useful for patterning very large scale
arrays of sub-micron aluminum dots or posts. Our work is focused on refining the fabrication
process and investigating the morphological stability of such metal nanostructures during
conversion to sapphire.
Recent Advances in Synthesis and Densification of Nanomaterials in Self-Propagating High-Temperature Regime
Authors: Puszynski Jan. A.
Published: March 2009

This invited talk reviews recent advances in synthesis of nanopowders in selfpropagating
high-temperature regime with emphasis on chemically-assisted combustion synthesis
of nonoxide ceramic nanopowders, specifically SiC, Si3N4, and AlN-BN. Recent results of in-situ
densification of intermetallic-ceramic composites formed from nanosized reactants in a combustion
regime are also presented. Examples of combustion synthesized TiAl3-Al2O3 and NiAl-Al2O3-CNT
nanocomposites are included and discussed.
Properties of Ag Doped Bi-Superconductors Prepared by Solid State and Sol-Gel Methods
Authors: Sýkorová Dagmar , Smrčková Olga , Vašek Petr
Published: March 2009

Superconductive ceramics with nominal composition Bi3.2Pb0.8Sr4Ca5Cu7Ox were
prepared by solid state synthesis with 10 wt% of nanopowdered silver and were compared with
those prepared by sol-gel method. The "in situ" polymerization route with citric acid and ethylene
glycol was used to enhance homogeneity of the reaction mixture. The quality of samples was
characterized by X-ray analysis, scanning electronic microscopy and the measurement of porosity.
The superconducting properties were investigated by the measurement of the temperature
dependence of magnetic susceptibility and by current voltage characteristic. All samples have
critical temperatures in the range from 109 to112 K. Addition of silver always increases the volume
of Bi-2223 phase and critical current density of the samples. Sol-gel samples reveal lower porosity,
higher bulk density and better connectivity of the grains, resulting in the further enhancement of
critical current density.
Transport Properties over Critical Currents for Ag-Sheathed Bi2Sr2CaCu2O8 Superconductors with Different E-J Dependence
Authors: Watanabe K. , Inoue T. , Awaji Satoshi , Nishijima Gen , Takahashi Ken Ichiro , Romanovskii V.R.
Published: March 2009

The current-carrying properties beyond a critical current determined by a voltage criterion
for Ag-sheathed Bi2Sr2CaCu2O8 (Ag/Bi2212) superconductors are examined at 10 K and 20 K in
magnetic fields. We prepared the in-field heat-treated Ag/Bi2212 wires, in order to obtain the
magnetic field alignment microstructure for Ag/Bi2212. The electric field and current density (E-J)
properties were evaluated for Ag/Bi2212 wires with and without the in-field heat-treatment. We
found that the E-J properties for the in-field heat-treated Ag/Bi2212 wires differ from those for the
out-of-field heat-treated ones, and are analogous to the E-J dependence for Bi-system high
temperature superconductors with the sintered-like grain morphology.
Single Crystal CVD Diamond Nuclear Detectors
Authors: Manfredotti Claudio
Published: March 2009

CVD diamond films have reached in recent years superlative improvements in their “
detector grade “ quality, with a time derivative which was never registered for other similar frontier
materials. The basic properties of high quality CVD diamond films make them very interesting for a
wide range of radiation detectors : they provide fast signals with very low leakage currents, they are
very radiation resistant, they have excellent thermal properties and they can be manufactured as
free-standing detectors. The recent availability of single crystal CVD diamond samples of extreme
good quality, suitable thickness and surface area has opened new application fields in nuclear
detection and dosimetry, such as, for instance, hadron therapy and neutron spectrometry in fusion
reactors. At the same time, strip and pixel detectors of unprecedented performances have been
successfully realized and exploited in the framework of high energy physics experiments.
The paper will review the more recent history of CVD diamond nuclear detectors with respect to
material quality, with a particular emphasis on epitaxial single crystals diamond, and the
achievements in terms of applications in some different fields.
Nanoporous-Carbon Coatings for Gas-Phase Chemical Microsensors
Authors: Siegal M.P. , Yelton W.G.
Published: March 2009

Nanoporous-carbon (NPC) is compared directly to commonly-used polymers as a gassorbing
coating material on surface acoustic wave (SAW) microsensor devices. The sensing
capability of these materials is measured for volatile organic compounds (VOCs), toxic-industrial
chemicals (TICs), and a chemical warfare agents (CWA) simulant. All of the coatings reversibly
sorb and desorb the volatile VOC and TIC compounds, however, NPC outperforms the polymers
over the range of analyte concentrations studied, especially at the lowest levels, by multiple ordersof-
magnitude. Conversely, NPC has good retention properties for the semi-volatile CWA simulant
tested, which while detrimental for use on a reversible SAW device, infers that NPC may be wellsuited
as a preconcentrator coating for such analytes. NPC is a highly-disordered low-density
carbon containing both nanopores and increased interplanar spacing between graphene sheet
fragments, self-assembles using pulsed laser deposition, has no residual-stress at room temperature,
is stable to 600 °C, and is chemically-inert in harsh environments. It has superior chemical and
aging properties compared to the conventional polymer films used in microsensor devices.
Synthesis of Bone-Like Hydroxyapatite/Collagen Nano-Composites by Soft-Nanotechnology
Authors: Kikuchi Masanori , Tanaka M.
Published: March 2009

Soft-nanotechnologies are based upon the synthesis technologies of nanomaterials and
construction technologies of nanostructures by life forms. They are expected as new preparation
methods for biomaterials that could be recognized as regular extracellular matrices (ECM) in our
body by cells. We applied the soft-nanotechnology to synthesis of artificial bones made of HAp and
collagen with bone-like nanostructure and examined their physical and biological properties. The
nanocomposite obtained indicates bone-like nanostructure. Computer simulation and FT-IR
suggested that the self-organization of HAp and collagen is based on chemical interaction between
calcium ions on HAp surface and carboxy groups on collagen. After implantation in rats and dogs,
the nanocomposites are resorbed by osteoclasts followed by osteogenesis; therefore, the
nanocomposites are recognized as bone in the living body. Resorption rate can be controlled by
crosslinkage. We also prepared sponge-like elastic porous body by gel-lyophilization technique
using additional small amount of collagen solution. Bone tissue reactions of it are the same as the
nanocomposites as prepared. The nanocomposites are now in clinical research in Japan to be
commercialized in near future by Pentax Co.
In Situ Characterization of Degradation Behavior of Plasma-Sprayed Coatings on Orthopedic and Dental Implants
Authors: LeGeros Racquel Z. , LeGeros John P.
Published: March 2009

Plasma-sprayed ‘HA’ coatings on commercial orthopedic and dental
implants were developed to combine the strength of the metal (Ti or Ti alloy) and the
bioactivity of the hydroxyapatite (HA). Several studies have shown that ‘HA’-coated
implants provided greater amount of bone attachment, higher bone-implant interfacial
strength and accelerated skeletal attachment. However, some reports on implant
failures have been attributed to coating delamination and coating early resorption of
the plasma sprayed ‘HA’ coating. This paper reviews studies on characterization and
degradation of plasma-sprayed ‘HA’ coatings on orthopedic and dental implants and
offers alternatives to plasma-spray method of providing calcium phosphate coating.
X-ray diffraction analyses showed that plasma-sprayed HA coating consists principally
of HA and amorphous calcium phosphate (ACP) with minor amounts of other
resorbable calcium phosphates (α- or β-tricalcium phosphates, tetracalcium
phosphate), sometimes calcium oxide. The HA/ACP ratios were found to range from
20HA/80ACP to 70HA/30ACP in coated implants from different manufacturers. In vitro
initial dissolution rates in acidic buffer (pH 6, 37oC) increased with decreasing HA/ACP
ratios in the coating because of the preferential dissolution of the ACP phase. These
results suggest that coating with very low HA/ACP ratio may result in the premature
resorption of the coating before the bone can attach to the implant thus causing
loosening and eventual failure of the implant.
Alternatives to plasma-sprayed ‘HA’ are implant surface modifications and low
temperature calcium phosphate coatings using electrochemical deposition method or
precipitation method.
Nano-Size Biomaterials Based on Ca-Aluminate
Authors: Hermansson Leif , Engqvist Hakan , Lööf Jesper , Gómez-Ortega Gunilla , Björklund Kajsa
Published: March 2009

This study deals with the microstructure and property profile of biomaterials within the
Ca-aluminate system (CA). Hydrated CA materials are stable in bone tissue, and thus not resorbable
as the Ca-phosphate materials are. Identified possible applications for CA-based materials are
within vertebroplasty and odontology. CA with ZrO2 particles as well as CA with glass particles
were examined with regard to mechanical properties, biocompatibility and bioactivity. The
hydrates formed - examined by HRTEM - are in the size range of 20-50 nm. With the studied
systems it is possible to obtain a combination of high and early strength, shape stability including
low expansion pressure, and in vivo bioactivity.
Microstructure and Properties of Biogenic Hydroxyapatite Doped with Magnetite
Authors: Szutkowska Magdalena , Leonowicz Marcin , Ivanchenko L.A.
Published: March 2009

In this study the hydroxyapatite powder was sintered together with magnetite
nanopowder, which due to its low reactivity is commonly used in medicine, eg. in magnetic
resonance. Two types of sintered materials, containing equal content 6 mol% of biogenic
hydroxyapatite (BGHAp), reinforced with 50 wt% of different glass phases, were tested. The same
technological conditions comprising two-stage sintering with T1 (1100°C) and T2 (780°C) were used
for both types of materials. For selected specimens 2 wt% of 9 nm powder of Fe3O4 was added. The
microhardness of the specimens varies within quite wide range from 150 to 508 HV0.025.
Compressive splitting strength of the specimens (measured along the sample diameter) is within a
range of 3.61 – 4.99 MPa. Young’s modulus, modulus of rigidity and Poisson’s ratio are in the
ranges of: 20.81 – 24.86 GPa, 7.89 – 9.71 GPa and 0.252 – 0.307, respectively. Indentation fracture
toughness KIC is within a range of 0.6-1.0 MPa m1/2. The hysteresis loops were determined in order
to asses the possibility of application of this material as affecting the drug delivery carriers. The
specimens exhibit magnetization of the order of 1.5 emu/g.
Preparation and Cathodoluminescence Properties of Ga-Doped ZnS Nanowalls
Authors: Lu M.Y. , Hsu Hung Chang , Chen Lih Juann
Published: March 2009

Quasi-vertical ZnS nanostructures with different Ga doping level ( ZnS:Ga nanowalls ) have been synthesized in high yield from the mixed powders in the vacuum furnace at 1150 oC. ZnS:Ga nanowalls were grown vertically on the substrate with the size in the range of several microns and the thickness down to 15 nm and have very rough edges. The possible growth mechanism of nanowalls is likely governed by a vapor-solid (VS) growth mechanism. Room-temperature cathodoluminescence spectra of ZnS : Ga nanowalls show two emission peaks at approximately 443 nm and 578 nm. The emission mechanisms are discussed.
Better Tissue Engineering Materials through the Use of Nanotechnology
Authors: Ercan Batur , Webster Thomas J.
Published: March 2009

Nanotechnology is defined as the use of materials with at least one dimension less
than 100 nm. Although nanotechnology has revolutionized many fields to date, it use in
medical applications remains at it infancy. This manuscript describes recent promising
studies made towards increasing tissue regeneration through the use of nano compared to
conventional materials.
Nano-Fabricated Aligned Spheroid for Cartilage Tissue Engineering
Authors: Otsuka H. , Satomi T. , Ueno Koji , Tateishi Tetsuya
Published: March 2009

Micropatterned PEGylated substrates with two-dimensional arrays of plasma-etched circular domains (diameter:100 micro-m) were prepared by coating of mercapto-functionalized poly(ethylene glycol) (PEG) on Au surface, followed by plasma-etching through a metal mask pattern with circular holes. The PEGylated region on the patterned substrate works to repel proteins, consequently, inhibits cell adhesion. Then the micro-patterning of bovine articular chondrocytes or rat primary hepatocytes hetero-spheroids underlaid with human umbilical endothelial cells (HUVEC) was achieved on the plasma-etched circular domains, exposing the base gold surface. Obtained results suggested that the efficiency of inhibiting non-specific protein adsorption significantly affects on construction of micro-patterned cell adhesion and hetero-spheroids. The formation of hetero-spheroid thus suggested is significantly modulated by suface properties, particularly non-fouling character of PEG region. These arrayed spheroids is promising materials for tissue and cell-based biosensors (TBB/CBB) as well as tissue engineering technologies.
Dielectrophoresis Force and the Electromechanical Responses of Elastomers
Authors: Kunanuruksapong Ruksapong , Sirivat Anuvat
Published: March 2009

In our research, we investigated the electrorheological responses and dielectrophoresis
force of the six elastomers at various electric field strengths and temperatures. For the
electrorheological responses, the effect of temperature, between 300 and 370 K, on the storage
modulus responses (ΔG′2kV/mm) and on the dielectric constants of elastomers were investigated
under applied electric field strengths varying from 0 to 2 kV/mm. The acrylic elastomers (AR70,
AR71, and AR72) have positive storage modulus responses and sensitivities with increasing
temperature and dielectric constant. In the case of styrene copolymers (SAR, SBS, and SIS), the
storage modulus responses and sensitivities increase and attain the maximum at the glass transition
temperature of the hard segment. We studied the dielectrophoresis forces of the six elastomers by
measured deflection distance under various electric field strengths (0–600 V/mm) and calculated the
force from non-linear deflection theory of the cantilever. The results show that the dielectrophoresis
forces of the six elastomers increase with increasing electric field strength. The acrylic elastomer
AR71 had the lowest electrical yield point (75 V/mm) and it generated the highest force (389 μN at
E = 600 V/mm). On the other hand, SIS had highest electrical yield point (400 V/mm) and it
generated the lowest force (67 μN at E = 600 V/mm). The dielectrophoresis forces depend on many
factors, such as dielectricity, conductivity, and storage modulus of the elastomers.
Fabrication of Electrode for Thermoelectric Oxide Materials
Authors: Kohri Hitoshi , Shiota Ichiro , Kato Masahiko , Ohsugi Isao J.
Published: March 2009

Thermoelectric materials can directly convert thermal energy into electrical energy.
Research and development of thermoelectric generators have been actively carried out to use waste
heat. Electrodes are necessary to take out the electrical power from the thermoelectric couples.
However, large portion of the generated electrical power is often lost at the interface between
electrode and thermoelectric materials. Though oxide materials are promising for a thermoelectric
generator at a high temperature, they are not practically used as the joining technique is not
established. Not only low contact resistance but also sufficient mechanical strength is required for
the joining. In this report, tin alloy solder was attempted for cold side junction to obtain low contact
resistance and high mechanical strength at the interface. Wettability of the solder to Ca3Co2O6 and the
thermoelectric generating properties were improved by adding titanium to tin alloy.
MEMS Rotational Actuator for High Force and Large Displacement
Authors: Currano Luke J. , Gee Danny , Churaman Wayne A. , Dubey Madan , Amirtharaj Paul , Yu Miao , Balachandran Balakumar
Published: March 2009

A MEMS thermal actuator that provides rotational or near-linear translational
displacements is investigated. This actuator provides a solution to applications that require highforces
and large displacements. Output moments up to 7x10-7 N-m and free rotations of up to 3
degrees were measured. These correspond to forces of up to 1.44mN at a displacement of 23.7μm,
yielding a work of 3.41x10-8 N-m. An electrothermal-mechanical model that considers temperature
dependence of material properties is presented, and the model predictions show good agreement
with actuator test data.
3C-SiC Hetero-Epitaxial Films for Sensors Fabrication
Authors: Anzalone Ruggero , Severino Andrea , Locke Christopher , Rodilosso Davide , Cristina Tringali , Saddow Stephen E. , La Via Francesco , D'Arrigo Giuseppe
Published: March 2009

Silicon Carbide (SiC) is a very promising material for the fabrication of a new category of sensors
and devices, to be used in very hostile environments (high temperature, corrosive ambient, presence
of radiation, etc.). The fabrication of SiC MEMS-based sensors requires new processes able to
realize microstructures on bulk material or on the SiC surface. The hetero-epitaxial growth of 3CSiC
on silicon substrates allows one to overcome the traditional limitations of SiC microfabrication.
This approach puts together the standard silicon bulk microfabrication methodologies
with the robust mechanical properties of 3C-SiC. Using this approach we were able to fabricate SiC
cantilevers for a new class of pressure sensor. The geometries studied were selected in order to
study the internal residual stress of the SiC film. X-Ray Diffraction polar figure and Bragg-
Brentano scan analysis were used to check to crystal structure and the orientations of the film. SEM
analysis was performed to analyze the morphology of the released MEMS structures.
High-Performance Lead-Free Barium Titanate Piezoelectric Ceramics
Authors: Karaki Tomoaki , Adachi Masatoshi , Yan Kang
Published: March 2009

Barium titanate (BaTiO3) ceramics with a high-density were fabricated by two-step
sintering method from hydrothermally synthesized 100 nm BaTiO3 nano-particles. The best
specimen with an average grain size of 1.6 μm and a density of 5.91 g/cm3 (98.3% of the theoretical
value). The dielectric constant was 4500 and electromechanical coupling factor kp was 45%. Large
piezoelectric constants d33 = 460 pC/N and d31 = -185 pC/N were observed in the specimens. This was
an important practical result towards obtaining a high d33 in non-lead-based BaTiO3 ceramics
manufactured by a low-cost process. These results also indicated the possibility of using BaTiO3
ceramics in piezoelectric devices at room temperature. Temperature dependence of dielectric
constant showed two peaks located at 24 and 126 oC, corresponding to orthorhombic-to-tetragonal
phase transition temperature Tot and Curie temperature Tc, respectively. Owing to the size effect of
nanocrystals, Tot shifted to 24 oC. The maximum of electromechanical coupling factor kp appeared
close to the phase transition temperature. It also caused a very large temperature coefficient of
resonance frequency from room temperature to 60 oC. Hysteresis curve measurement showed a very
low coercive field Ec = 115 V/mm. A large Poisson’s ratio, about 0.38, was determined from the ratio
of overtone frequency and resonant frequency in the planar mode. The high Poisson’s ratio and the
large dielectric constants are most likely the origin of the high piezoelectric constants in the ceramics.
Glass Microspherical Lasers
Authors: Nunzi Conti Gualtiero , Soria S. , Berneschi Simone , Brenci M. , Cosi F. , Pelli Stefano , Armellini Cristina , Chiappini Andrea , Chiasera A. , Jestin Yoann , Ferrari Maurizio , Moser Enrico , Ghisa L. , Trebaol S. , Dumeige Y. , Féron P. , Righini G.C.
Published: March 2009

We report experimental results obtained in our laboratories in the development of Er3+-
doped glass microspherical cavities for the fabrication of compact and low threshold laser sources
at 1.55 μm. We investigate three different approaches in order to fabricate the microspheres
including direct melting of Er3+-doped glass powders, coating of silica microspheres with an Er3+-
doped sol-gel layer, and synthesis of Er3+-doped monolithic microspheres using the sol-gel route in
acid catalysis. Details of the different fabrication processes are presented together with the
photoluminescence characterization in free space configuration of the microspheres and of the glass
precursor. We analyse the photoluminescence spectra of the whispering gallery modes of the
microspheres exited using evanescent coupling and we demonstrate laser action in a wide range of
wavelengths around 1.55 μm.
Adaptive Solution for Intelligent Cable Vibration Mitigation
Authors: Faravelli Lucia , Fuggini Clemente , Ubertini Filippo
Published: March 2009

The mechanics of cables is caught either by numeric or analytic models which are able to
predict the nonlinear dynamic response of this structural elements with the desired level of
approximation. Although cable dynamics has been widely explored in the literature, efforts are still
required in the field of cable vibration mitigation to conceive an economical, feasible and robust
control strategy. An adaptive control strategy combining a distributed passive solution with a semiactive
actuation is here proposed for the purpose of reducing the spatial cable vibrations. The
effectiveness of the proposed control policy is investigated by means of experimental tests and a
suitable numeric scheme.
Remotely Controllable SHM System for a Concrete Box-Girder Bridge
Authors: Lee Jong Jae , Koo Ki Young , Hong Jun Young , Yun Chung Bang
Published: March 2009

Many bridges are located in rural areas where conventional Internet services are not
readily available. 3.5 generation mobile telecommunication technology, HSDPA (High Speed
Downlink Packet Access), is currently commercialized in 55 countries to make the Internet access
possible in anywhere the mobile phone service is available. In this study, a novel framework of
remotely controllable SHM systems is proposed for bridges without the conventional Internet service
utilizing HSDPA technology and remote desktop software. The proposed SHM system has benefits
such as remote maintenance of SHM systems and a low cost network implementation. The feasibility
of the proposed framework has been demonstrated by field tests on a concrete box-girder highway
bridge in operation.
Damage Detection with Auxiliary Subsystem
Authors: Vestroni Fabrizio , Ciambella J. , dell'Isola Francesco , Vidoli Stefano
Published: March 2009

Among Non-Destructive Evaluation, vibration-based methods respond to the current ten-
dency which is to integrate into the structure identication and monitoring systems; to this
aim transducers and sensors are embedded with the mechanical system and driven by suitably
designed electronic controllers.
The major limit of this and the other indirect identication techniques based on frequency
response measurements turns out to be the small sensitivity to local variations of mechanical
characteristics: it re
ects on a uncertainty on the identied parameters, since it implies a small
curvature of any reasonable identication functional build on these quantities.
An enlightening example for the application of the proposed technique is given through a beam-
like structure coupled to a network of piezoelectric patches. Although the forces exerted by the
piezoelectric transducers are not large, the choice of such a kind of actuators/sensors implies
the remarkable advantage of dealing with highly sensitive and easily tunable devices.
Optimization of Signal Pre-Processing for the Integration of Cost-Effective Local Intelligence in Wireless Self-Powered Structural Health Monitoring
Authors: Monnier Thomas , Guy Philippe , Lallart Mickaël , Petit Lionel , Guyomar Daniel , Richard Claude
Published: March 2009

Recent research in Structural Health Monitoring (SHM) showed the ability of guidedwave
based sensors networks to detect, localize and classify damage in its early stage. But, most of
them still require the wiring of numerous devices. To avoid this technical restraint, particularly in
airborne structures, wireless SHM system offer mass and cost savings, but powering the devices
remains heavy. In this paper, actuators and sensors are powered by piezoelectric microgenerators,
which harvest energy from the environing mechanical stress. The efficiency of the extraction
process is optimized by a non-linear processing of the piezovoltage named Synchronized Switch
Harvesting. Previous work showed that such techniques provide a stand-alone power source, whose
performances meet the requirements of Wireless Transmitters and Receivers. Indeed, each sensing
node has to feature its own power source in order to acquire its logical autonomy and thus, provide
decentralized intelligence to SHM network. Although the diagnosis will be centralized, the amount
of data passed to the central core of the network should be reduced to preserve a positive energy
balance of the node. Various algorithms are compared in terms of sensitivity and computational
cost, the latter directly impacting the consumption.
Continuing Structural Health Monitoring after Repair: Starting from Scratch?
Authors: Kullaa Jyrki
Published: March 2009

Aging structures need repairing if their lifetime is to be extended. If the structure has been
monitored before and after repair, the information from both configurations can be utilized. The data
before repair include the environmental or operational influences, whereas the data after repair
represent the current structural condition. Also, if damage is proportional to the worked
modifications, its extent can be assessed solely from the measurement data; no finite element model
is needed. The proposed method is verified with a numerical model of a vehicle crane.
Wearable Biosensors for Monitoring Wound Healing
Authors: Pasche Stéphanie , Angeloni Silvia , Ischer Réal , Liley Martha , Luprano Jean , Voirin Guy
Published: March 2009

Continuous health monitoring often requires hospitalization, which can become an
expensive and inconvenient choice for the patient. In this perspective, wearable sensors that allow in
situ biosensing constitute a very promising technology. This work aims to develop immunosensors
for continuous monitoring of the wound healing process, based on pH changes, as well as on the
concentrations of inflammatory proteins such as the C-reactive protein (CRP). Sensing principles
include the use of responsive hydrogels that swell in response to changes in the surroundings, and
the use of functional surfaces that specifically recognize the target protein. The detection principle is
based on an optical signal, using the evanescent field of light propagating along a waveguide,
probing refractive index changes. An optical sensing system that can be integrated in a wound
dressing patch has been designed, including a white light source (LED), and a spectrometer for
detection. The sensor was successfully tested in the laboratory with biological samples (blood
serum), demonstrating reversible pH measurements between pH 6-8, and detection of changes in the
concentration of CRP between 1 and 100 μg/ml. The sensor will later be integrated into wound
dressings or bandages, forming a sensing patch that is connected via optical fibres and electrical
wires to the detection system and power supply. This novel technology will be particularly valuable
in applications such as the supervision of skin grafts and ulcer treatments.
Investigating the Thrust Production of a Myliobatoid-Inspired Oscillating Wing
Authors: Moored Keith W. , Smith W. , Hester J.M. , Chang W. , Bart-Smith Hilary
Published: March 2009

Myliobatidae is a family of large pelagic rays including cownose, eagle and manta rays.
They are extremely efficient swimmers, can cruise at high speeds and can perform turn-on-a-dime
maneuvering, making these fishes excellent inspiration for an autonomous underwater vehicle.
Myliobatoids have been studied extensively from a biological perspective; however the fluid
mechanisms that produce thrust for their large-amplitude oscillatory-style pectoral fin flapping are
unknown. An experimental robotic flapping wing has been developed that closely matches the
camber and planform shapes of myliobatoids. The wing can produce significant spanwise
curvature, phase delays down the span, and oscillating frequencies of up to 1 Hz, capturing the
dominant kinematic modes of flapping for myliobatoids. This paper uses dye flow visualization to
qualitatively characterize the fluid mechanisms at work during steady-state oscillation. It is shown
that oscillatory swimming uses fundamentally different fluid mechanisms than undulatory
swimming by the generation of leading-edge vortices. Lessons are distilled from studying the fluid
dynamics of myliobatoids that can be applied to the design of biomimetic underwater vehicles using
morphing wing technology.
Deployable Structures in Plants
Authors: Kobayashi Hidetoshi , Horikawa Keitaro
Published: March 2009

The deployment of leaves with plane surface and straight parallel folds, as observed in
leaves of hornbeam and beech, was investigated by using numerical methods. In both species the
veins are angled at 30° to 50° from the midrib, when the leaves are outstretched. Although a higher
angle allows the leaf to be folded more compactly within the bud, it has very small leaf area in the
early stage of unfolding. The midrib of leaf grows very slowly at first and then it does with an
almost constant speed. From the numerical simulation, it was found that the midrib grows with the
minimum unfolding energy. The deployment of flowers was also investigated from mechanical
point of view. A potato flower has five or six petals with triangle gussets between petals. The bud
volume becomes largest when the number of petals, N, is five. However, the energy for unfolding
of the model with N = 5 or 6 is smaller than those of other models, if the energy can be represented
by the total kinetic energy during unfolding.
Generation of Smart Structures on the Basis of In Situ Configuration of Shape Memory Alloys
Authors: Langbein Sven , Welp Edwald G.
Published: March 2009

An outstanding feature of shape memory alloys (SMAs) is their potential to produce
different functional effects like thermal shape memory or superelasticity in one component. The
purpose of the present study is to find a way to create a universal component with properties
adjustable for various applications solely by modifying the local material properties. We refer to
this process as in-situ configuration. The basis of in-situ configuration of the materials’ properties is
generated by first deactivating the shape memory effect in the whole element and then local
activation of the shape memory effect by use of local heat treatment. The NiTi-elements presented
in this study offer various options, since they do not feature perceptible thermal shape memory or
superelasticity due to a high dislocation density. Instead, to achieve a specific local function, the
elements are subjected to in-situ heat treatment carried out by a local resistive heating element.
There is a need to adjust the duration and intensity of the heat input in order to obtain different
functional properties.
Investigating SMART Membranes and Coatings by In Situ Synthesis of Iron Oxide Nanoparticles in PVA Hydrogels
Authors: Stylios George K. , Wan Tao Yu
Published: March 2009

This paper reports a novel method of developing SMART nanocomposite membranes
and coatings by in situ synthesis of iron oxide particles in a Poly(vinyl alcohol) (PVA)matrix, using
co-precipitation of different amounts of Fe(II) and Fe(III) taken in an alkaline medium. Poly(vinyl
alcohol) was used to encapsulate iron oxide nanoparticles, as scaffold for particle nucleation and its
influence on particle size and on magnetic properties were studied. The ferrogels were prepared by
a freeze/thawing process of the solutions containing magnetite nanoparticles. Magnetite particles
with an average diameter of 20-40 nm were obtained homogeneously within the matrix because of
the tridimensional structure and chelating capacities of PVA. Calcium-alginate PVA gel was used to
encapsulate the iron oxide/PVA nanocomposite. The mechanical properties and the saturation
magnetization of the system were measured. The combination of magnetic properties of iron
nanoparticles with the biocompatibility of calcium-alginate suggests that these materials have great
potential for use as controlled delivery systems activated externally by magnetic stimuli.
Dielectric Elastomer Actuators as Elements of Active Vibration Control Systems
Authors: Papaspiridis Fotis G. , Antoniadis I.A.
Published: March 2009

Dielectric elastomer actuators (DEA) are a new class of actuators, exhibiting electric
field-induced strains. Upon electrical stimulation they can provide large strains and consequently
electrical forces. These abilities along with their high compliance make them candidates for active
vibration control. This parer presents a general framework for the usage of DEA as elements of
active vibration control systems. The electrical and mechanical model of the DEA and a basic
control law, for varying the voltage, is reviewed. The basic idea is to reduce the acceleration of the
vibrating equipment when the system approaches its equilibrium. The application of the actuator in
a single-dof-mass-spring system is modeled. The results with and without control are presented and
show the large capabilities of the actuator to suppress the vibrations induced by an external force.
DEA has viscoelastic properties, which can further increase the damping capabilities of the
vibration absorber but on the other hand produce a time delay, which must be taken into account.
Furthermore, the technological issues arisen -structure of the actuator, power and equipment needs,
effect of prestrain and frequency, distributed actuation- are discussed.
Carbon Nanotube Yarns as High Load Actuators and Sensors
Authors: Mirfakhrai Tissaphern , Oh Ji Young , Kozlov Mikhail , Fang Shao Li , Zhang Mei , Baughman Ray H. , Madden John D.
Published: March 2009

Carbon nanotubes have attracted extensive attention in the past few years because of
their appealing mechanical and electronic properties. Yarns made through spinning multiwall
carbon nanotubes (MWNTs) have been reported. Here we study the application of these yarns as
electrochemical actuators, and as force sensors. MWNT yarns are mechanically strong with tensile
strengths reaching one GPa. When charge is stored in the yarns they change in length. This is
thought to be because of a combination of electrostatic and quantum chemical effects. We report
strains up to 0.6 %. The charged yarns can also generate current and change in voltage in response
to a change in the applied tension. Electrostatic and quantum effects contributing to actuation are
introduced along with the effect of the yarn geometry on actuation and other contributing factors.