bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of Ferromagnetic Filled Carbon Nanotubes and their Biomedical Application
Authors: Leonhardt A. , Mönch Ingolf , Meye Axel , Hampel Silke , Büchner B.
Published: March 2009

Especially during last years, fundamental discoveries of various species and
modifications of carbon nanotubes have stimulated research on their application including in
human medicine. The success of these applications depends significantly on the physical,
chemical and biological properties of the carbon nanotubes and their supplements.
In our presentation we report on the synthesis of Fe-filled carbon nanotubes, their structural
and magnetic properties and propose novel types of such functionalised and filled multiwalled
carbon nanotubes with various advantages for an application in human medicine,
especially in anti-tumour therapeutic concepts.
These nanotube structures represent multi-functional nano-scaled containers for different
medical treatments including magnetically guided hyperthermia. Furthermore these chemical
inert and stable carbon nanocontainer can be act as a new drug delivery carrier system. In
principle, both, a filling of nanotubes by an open-fill-close process or an attachment of
argents on the outside of the carbon nanotube is possible.
Chemical Vapor Infiltration of Carbon Fiber Felts from Methane: Influence of Surface Area / Volume Ratios
Authors: Zhang W.G. , Zhu Yong Ping , Hüttinger K.J.
Published: March 2009

Isothermal, isobaric chemical vapor infiltration of carbon fiber felts with fiber volume fractions of
7.1% and 14.2% were investigated at infiltration times from 20 to 120 hours, using a constant temperature of
1095 oC and a methane pressure of 22.5 kPa. Bulk densities and the density profiles as well as porosity at
various densification stages were determined. Inside–outside densification was obtained in the most
infiltrations, the gradients of densification along the infiltration depth decrease with increasing of residence
time and infiltration times. Outside–inside densification occurs only in the felt with the lower fiber volume
fraction at final infiltration stage and at longer residence times. Microstructure of the obtained matrix carbon
was analyzed with a polarized light microscopy. Abruptly change from low/medium textured carbon to
medium/high textured carbon are observed in both of the carbon fiber felts, whereas the thickness of the first
lower textured layer is about 14 micros in the felt with a fiber volume fraction of 7.1%, whereas it is only 2
micros in the felt with a fiber volume fraction of 14.2%, which is caused by an increasing of initial surface area
/ volume ratio, [A/V], from 33 to 71 mm-1. Results are completely in agreement with the previous simulations
studies on the influence of [A/V] ratios.
Advanced Design Concepts and Modeling of Composite Materials in Emerging Applications
Authors: Hui David , Kireitseu Maksim , Tomlinson Geoffrey R. , Kompis Vladimir
Published: March 2009

Nanoparticles and carbon nanotubes-containing composites were deposited on a metal
substrate by a micro-arc oxidizing technique. The nanocomposites were developed for their applied
researches in fuel tanks and containers of space shuttles. Carbon-nanotube-reinforced composite
materials are relatively new class of materials that require extensive investigations in emerging applications
at low (cryogenic) and high temperature environments. Two types of nanoparticlereinforced
polymeric composites were studied at flexural tests and thermal cycling between 200°C
and -80°C temperature with no visual cracks for two and half times more than a matrix. The polymer
type and the curing process control the thermal cycle response and ultimate durability of the
composites in extreme temperature environments. To validate the use of the simplified twodimensional
models, a comparison is made with three-dimensional calculations.
Static Fatigue of a 2.5D SiC/[Si-B-C] Composite at Intermediate Temperature under Air
Authors: Moevus M. , Reynaud Pascal , R'Mili M. , Godin N. , Rouby Dominique , Fantozzi Gilbert
Published: March 2009

Non-oxide ceramic-matrix composites (CMCs) are subjected to be used in aeronautic
applications which require very long duration (up to 100 000h) of materials at high temperatures
and under air. Recently a self-healing [Si-B-C] matrix has been developped to enhance strongly the
lifetime of CMCs under air.
The aim of this work is to study the mechanical behaviour of a SiCf/[Si-B-C] composite with a
self-healing matrix under static fatigue, and to determine its lifetime. During the mechanical tests,
acoustic emission is detected in order to characterize the damage of the composite in addition to the
measurement of the longitudinal deformation of the composite. The analysis of acoustic emission
follows a non-supervised procedure of classification. Each event of acoustic emission is described
by a set of several parameters, and the total activity can be divided in four classes. The assignment
of each class to a damage mechanism is required to follow the spread of damage during fatigue and
to determine the mechanisms controlling the failure of the composite.
Synthesis of SiCN-Precursors for Fibres and Matrices
Authors: Motz Günter
Published: March 2009

Main applications for preceramic polymers (precursors) are ceramic fibres, ceramic matrices and coatings. The requirements for the polymer are determined by the intended application and differ from a cross-linkable liquid to meltable and curable or unmeltable but soluble solid. For applying these precursors on a larger scale, they must be processable by conventional polymer processing techniques. Furthermore, the starting material should be cheap and readily available, and the synthesis should be uncomplicated. Considering these criteria, specially tailored precursors in the system Si-C-N (silazanes) were synthesized in a laboratory scale by ammonolysis of different chlorosilanes. After investigating the properties suitable precursors were produced in a pilot plant (approx. 5 kg). Variation of both the functional groups of the chlorosilane educts and the synthesis conditions lead to precursors with tailored properties (liquid, solid, soluble) and a special cross-linking behaviour (catalyst, initiator, electron-beam). Selected applications with the special precursors were presented for producing ceramic SiCN-fibres via melt-spinning also with a precursor modified with multi-walled carbon nanotubes as well as for processing a new kind of metal-ceramic gradient compound by reaction of SiCN-precursors with Ti-powders during pyrolysis.
The Influence of SiC Nano-Precipitates on the Interface Structure in C/C-SiC Composites
Authors: Krnel Kristoffer , Stadler Zmago , Kosmač Tomaž
Published: March 2009

The goal of our research is to develop a carbon-carbon-silicon carbide composite that
will unite high fracture toughness of carbon-carbon composite with good oxidation and abrasion
resistance and good thermal conductivity of silicon carbide. That can be achieved by the
preparation of functionally graded C/C-SiC composites. For the production of C/C-SiC composites
with a gradient structure of the ceramic matrix – from a carbon matrix in the core to a SiC matrix on
the surface new materials based on C/C composite with SiC nano-particles dispersed in the matrix
were produced. Since for the thermo-mechanical properties of such materials, the interface between
the carbon fibres and the matrix phase is crucial, we studied the influence of SiC precipitation from
the matrix phase on the interface structure and the mechanical properties of C/C-SiC composites.
The results show that SiC nano-particels are precipitating around the carbon fibres influencing the
interface structure and consequently also the mechanical properties.
Manufacturing and Properties of CMCs Containing Ti Filler with Improved Intra-Matrix Bond
Authors: Stantschev G. , Friess Martin , Krenkel Walter
Published: March 2009

Ceramic matrix composites (CMCs) were manufactured via polymer infiltration and
pyrolysis) PIP process. In order to improve the performance of CMCs as well as to accelerate the
manufacturing process, micro-sized powders of Ti are employed as active fillers. To further
increase mechanical properties of the CMC, a novel approach is made to strengthen intra-matrix
bond by treating the CMC with titanium(IV)-diisopropylate after first PIP processing prior to each
PIP cycle.
Modelling of the CVI Processes
Authors: Vignoles Gerard
Published: March 2009

The chemical vapour infiltration (CVI) process is used to fabricate the interphases and
matrices of CMCs. This process involves complex physico-chemical phenomena such as the
transport of precursor, carrier, and by-product gases in the reactor and inside a fibrous preform,
chemical reactions (pyrolysis and deposition), and the structural evolution of the preform. It is able
to provide high-quality materials because the process conditions are rather mild with respect to the
fibres ; however it is expensive and sometimes difficult to optimize. Many variations of the basic
concept have been proposed in the past decades, introducing thermal and pressure gradients, in
order to increase the efficiency. This process has been the object of extensive modelling efforts,
because of imperative optimization needs. The present work is an attempt to provide a synthetic
view of these models, focusing on several features of CVI modelling : i) Modelling CVI requires a
multi-scale strategy, with models ranging from process scale down to atomic scale, ii) Original
physicochemical couplings are involved, which require the development of adequate treatments, iii)
There is a hierarchy of model refinement, ranging from fully detailed models to quasi-analytical
predictions.
Direct Synthesis of Tungsten Oxide Nanowires on Microscope Cover Glass
Authors: Cheong F.C. , Zhu Y.W. , Varghese B. , Lim Chwee Teck , Sow C.H.
Published: March 2009

A simple technique to synthesis crystalline Tungsten Oxide nanowires is presented. Using
a standard thermal hotplate, a pure 99.9% tungsten foil is annealed to 484 ± 5 oC under ambient
condition to generate vapor deposition of the heated materials on a piece of 150μm thick glass cover
slide pressing on the tungsten foil. Tungsten oxide nanowires are found to deposit on the cover slide
facing the heated tungsten foil. These tungsten oxide nanowires were characterized with SEM, TEM,
EDX, micro-Raman and XRD. The crystalline nanowires were found to be straight and clean with a
diameter of 10-300nm and a length of a few tens of micrometers.
Many-Scale Simulation of ABS/PC Blends for the Automotive Industry
Authors: Fermeglia Maurizio , Ferrone Marco , Cosoli Paolo , Paneni Maria Silvia , Venica Roberta , Pricl Sabrina , Sinesi Sabino , Posocco Paola , Martinelli Laura
Published: March 2009

Industrial scraps cannot be reused in an advantageous way, mainly because of their
degradation. When possible, rejects are added to the virgin material for new molding, although the
amount of recycled block copolymer cannot exceed 15% of moldable material to obtain good final
performances. The remaining amount of scraps then follows three different routes: i) employment in
very poor applications, ii) land filling, and iii) thermal treatment. For this reason, post industrial
rejects constitute a major problem both from the standpoint of the European legislation and policy,
and from the economic side where enterprises are concerned. In this work we have applied a
multiscale simulation approach to study the nanostructured equilibrium morphology of blends
consisting of mainly recycled block copolymers of special interest in the automotive industry. The
main goal was the definition of the possible causes leading to incompatibility due to non virgin
materials. In particular, starting from atomistic-based simulations we derived a procedure to 1)
describe in appropriate fashion the polymer chains in terms of the relevant Gaussian models, and 2)
determine the relevant Flory-Huggins interaction parameters. Finally, we coupled mesoscale model
with finite elements codes to obtain a quantified structure-property relationship for mechanical
modulus and coefficient of thermal expansion.
Industrial Ink-Jet Application of Nano-Sized Ceramic Inks
Authors: Dondi M. , Matteucci F. , Gardini Davide , Blosi Magdab , Costa Anna L. , Galassi Carmen , Baldi Giovanni , Barzanti A. , Cinotti E.
Published: March 2009

Ink-jet printing is becoming a leading technology for traditional ceramics, due to its capacity of reproducing highly resolved and customized images on tile surfaces. Nano-sized inks, produced by the polyol synthesis route, proved to fulfil the printing requirements, tailoring their chemico-physical properties (e.g. viscosity, surface tension) on industrial ink-jet devices, so representing a major breakthrough in the quadrichromy process.
Synthesis and Cathodoluminescence Study of Well-Aligned Planar-Tip and Tapered-Tip ZnO Nanorods
Authors: He J.H. , Wang C.W. , Liao K.F. , Chen Lih Juann
Published: March 2009

Vertically aligned ZnO nanorods have been synthesized on a-plane sapphire via a metal
catalyzed vapor phase transport and condensation process in a two-zone vacuum furnace. Planar-tip
ZnO nanorods were synthesized using commercial ZnO and graphite powder as the source of Zn
vapor controlled by a simple vapor-liquid-solid (VLS) process. On the other hand, tapered-tip ZnO
nanorods were synthesized from pure ZnO powder governed by both VLS and vapor-solid processes.
From room temperature cathodoluminescence measurements, planar-tip ZnO nanorods are applicable
for room temperature UV nanolasers.
Structural Modification of Doped and Undoped Nanocrystalline TiO2 by Temperature-Resolved XRPD
Authors: Matteucci F. , Cruciani G. , Dondi M. , Baldi Giovanni , Dalconi M.C. , Barzanti A. , Lorenzi G. , Meneghini C.
Published: March 2009

Nanocrystalline titania pigments were produced by a novel
synthesis route consisting of a high temperature forced hydrolysis in a
coordinating high-boiling solvent. The effect of synthesis conditions as well
as doping with Cr, Sb and V on the particle size and on the anatase-to-rutile
transformation was studied by temperature-resolved synchrotron powder
diffraction. The experiments were performed directly on as-synthesized low
concentration suspensions of titania nanoparticles (up to 230°C) and on
dried titania nanoparticles (up to 950°C). Crystallite size of as-synthesized
nanoparticles is in the 5 to 50 nm range, being affected by the synthesis
conditions as well as by doping and exhibits a slow-rate coarsening trend
with temperature. The anatase-to-rutile transformation is drastically
influenced by both synthesis conditions and doping. In particular, doping
affected the anatase-to-rutile transformation rate, while the synthesis
conditions influenced the phase composition, causing the appearance of
brookite.
Ferromagnetic Property of Co and Fe-Implanted ZnO Thin Film at Room Temperature
Authors: Choi W.K. , Angadi B. , Park H.C. , Lee J.H. , Song Jong Han , Kumar Ravi
Published: March 2009

The results Co and Fe implanted ZnO thin films were studied before and after 200 MeV Ag
ion irradiation. The as-implanted films shows the presence of nano sized Co and Fe clusters as seen
through XRD patterns and exhibited high resistivity compared to un-implanted films. After Ag ion
irradiation the Co and Fe clusters get dissolved in ZnO lattice and the films resistivity reduced to half
of the as implanted values. The magnetic properties of Ag irradiated films were confirmed through
magnetization hysteresis and Co implanted films exhibit higher magnetization compared to Fe
implanted films.
Magnetic Field Effects on Current, Electroluminescence and Photocurrent in Alq3 Organic Light Emitting Diodes
Authors: Veeraraghavan Govindarajan , Nguyen Tho Duc , Sheng Yu Gang , Mermer Omer , Wohlgenannt Markus
Published: March 2009

We report on the experimental observation of large magnetoresistance in Alq3 organic light-emitting diodes (OLEDs). Very similar magnetic field effects (MFEs) of comparable magnitude are also observed in electroluminescence and photocurrent measurements. We also report on the frequency response of the magnetoresistance effect at frequencies below 100 kHz. To the best of our knowledge, the mechanism causing these MFE is currently not known.
Magnetoresistance of Post-Annealed Iron Nitride Related Thin Films
Authors: Kikkawa Shinichi , Sakon K. , Kawaai Y. , Takeda T.
Published: March 2009

Iron nitrides thermally decompose to α-Fe releasing their nitrogen above 300°C. MR
effect was found out in the thin films obtained by post-annealing of the following two kinds of sputter
deposited iron nitride related films. (1) α-Fe particles dispersed in AlN granular film was obtained by
an annealing of Al0.31Fe0.69N sputter deposited film in hydrogen. The MR=0.82% was found out in
this nitride system. (2) Fe3O4 thin films were prepared by thermal decomposition of sputter deposited
iron nitride films in low oxygen partial pressure. The iron nitrides were defect rock salt type γ΄˝-FeNx
(0.5≤x≤0.7) and zinc blende type γ˝-FeNy (0.8≤y≤0.9) at the sputter nitrogen gas pressure of 1Pa and
6Pa. MR ratios of the oxide films were about 2%.
Crossover Antiferro-Superparamagnetism and Related Kondo-Like Anomalies of Resistivity in Clustered Fe/Cr Multilayers
Authors: Ustinov V.V. , Romashev L.N. , Milyaev M.A. , Krinitsina T.P. , Burkhanov A.M.
Published: March 2009

The magnetic and magnetoresistive properties of nanostructured Fe/Cr multilayers with
ultra-thin Fe layers (the nominal Fe thickness tFe is down to 0.3 Å) have been investigated at low
temperatures (down to 2 K) in magnetic fields up to 90 kOe. Nanostructures were MBE grown in
ultrahigh vacuum on single crystal MgO substrates. It is shown that Fe layers in nanostructures with
tFe < 2 Å are not continuous but consist of separate ferromagnetic clusters. Such cluster-layered
nanostructures exhibit superparamagnetic properties and the Kondo-like behavior of resistivity.
Composite Polymeric Foams Produced by Using Magnetic Field
Authors: Sorrentino Luigi , Aurilia Marco , Forte Giovanni , Iannace Salvatore
Published: March 2009

Polymeric foams with different concentrations of Fe particles were prepared. The effects of
magnetic field (MF) during the foaming process was analyzed. Mechanical properties and cell
morphology of samples foamed with and without the application of the MF were compared.
As revealed by optical and electronic scanning microscopy the magnetic field induced an
alignment of Fe particles. The compressive mechanical tests performed on the foams showed an
enhancement of the properties with the increase of particles concentration. When the iron particles
were aligned by the magnetic field an improvement of the mechanical properties in the alignment
direction was measured when compared to the samples with the same particle content.
The effect of particles alignment was evident starting from low weight concentrations (5%wt).
The mechanical behavior of the samples prepared by using the magnetic field was strongly
anisotropic: in the field direction the mechanical behavior was higher than that in the orthogonal
direction.
The development of cellular structures produced by applying a magnetic field during the
foaming process allows the design of anisotropic structures with cell morphology and mechanical
properties tailored for desired directions.
Novel Magnetostrictive Microcantilever and Magnetostrictive Nanobars for High Performance Biological Detection
Authors: Cheng Zhong Yang , Li S.Q. , Zhang K.W. , Fu L.L. , Chin B.A.
Published: March 2009

High performance biosensors are urgently needed from medical diagnosis, to food
safety/security, to the war on bio-terrorist. Recently, magnetostrictive microcantilever (MSMC) and
magnetostrictive particle (MSP) have been developed as high performance biosensor platform. Both
MSMC and MSP are wireless sensors and exhibit advantages over current acoustic wave biosensor
platforms. Theoretical analysis and experimental results indicate that micro/nano scale MSMC and
MSP have ultra-high sensitivities. However, in real detection, there is a challenge faces all
micro/nano scale sensors because of their small size. That is, a long time is required for the tiny
sensors to react with the target species. Due to the magnetic and wireless nature, MSP provides a
unique way to bring the nanosensors to target species. The fabrication of bar-like MSPs in nanoscale
is reported. Amorphous Fe-B alloy was selected as target magnetostrictive materials for fabrication.
The properties of these nanobars were determined. The morphology and magnetic properties of the
nanobars were characterized. The results ware analyzed and the size effect on the microstructure and
properties is discussed.
Non-Isothermal Crystallization Kinetics and Melting Behaviors of Thermoplastic/Liquid Crystalline Polymer Blends of Poly(Trimethylene Terephthalate)/Vectra A950
Authors: Pisitsak Penwisa , Magaraphan Rathanawan
Published: March 2009

The non-isothermal crystallization and subsequent melting behaviors of
poly(trimethylene terephthalate), (PTT)/Vectra A950, (VA) blends with different VA contents were
studied by differential scanning calorimetry. The effects of VA on the non-isothermal
crystallization kinetics of PTT were discussed based on the Ozawa model. It was found that VA has
a nucleation effect on PTT crystallization. The triple melting endotherms were found in the
subsequent melting thermograms. The blends are clearly immiscible as verified by the unchanged
Tg and morphological results.
A New Synthesis Route to Prepare Polyaniline (PANI) Nanotubes Containing Magnetic Nanoparticles
Authors: De Araújo Ana Claudia V. , Alves S. , Azevedo W.M.
Published: March 2009

In this work we report the preparation and characterization of a polyaniline/magnetite
(PANI)-Fe3O4 nanocomposite, with average diameter around 50 nm and tubular morphology. The
tubular nanocomposite was synthesized by an in situ polymerization of aniline using Fe3O4
nanoparticles as an oxidant agent. The Fe3O4 nanoparticles with narrow size distribution were
synthesized by co-precipitation technique and the products were characterized by powder X-ray
diffractometry (XRD), Fourier transform infrared (FTIR), scanning electron microscopy (SEM), and
transmission electron microscopy (TEM).
CNT Based Sensors
Authors: Hierold Christofer , Helbling Thomas , Roman Cosmin , Durrer Lukas , Jungen Alain , Stampfer Christoph
Published: March 2009

Carbon Nanotubes (CNT) are intensively studied as a new functional material
for sensors, nanosystems and electronic systems. Single-walled carbon nanotubes (SWNTs)
for example show unique mechanical and electromechanical properties and they change
electronic properties by interacting with the environment (e.g. for chemical and biochemical
sensing). Therefore CNTs are very promising candidates for active elements in future
nanoscaled transducers. Concepts for carbon nanotube sensors for mechanical and chemical
quantities are presented. We focus on single-walled carbon nanotubes as "simple" macro
molecular functional structures with an option for low scale integration in micro and nano
electromechanical systems (MEMS and NEMS).
Electromechanical Behavior of Single and Multiwall Carbon Nanotubes
Authors: Pantano Antonio
Published: March 2009

Carbon nanotubes (CNTs) can be metallic or semiconductors depending simply on
geometric characteristics. This peculiar electronic behavior, combined with high mechanical
strength, make them potential building blocks of a new nano-electronic technology. High resolution
images of CNTs often disclose structural deformations such as bent, twisted, or collapsed tubes.
These deformations break the tube symmetry, and a change in their electronic properties should
result. A computationally effective mixed finite element-tight-binding approach able to simulate the
electromechanical behavior of single and multiwall nanotubes used in nano-electronic devices is
presented. The finite element (FE) computes the evolution of atomic coordinates with deformation
and provides these coordinates to a tight-binding (TB) code, enabling computation and updating of
the electrical conductivity. The TB code is engineered to realize dramatic computational savings in
calculating deformation-induced changes in electrical transport properties of the nanotubes.
Strain Enhancement within Cantilevered, Piezoelectric MEMS Energy Scavenging Devices
Authors: Miller Lindsay M. , Emley N.C. , Shafer P. , Wright Paul K.
Published: March 2009

We present the current status of cantilevered MEMS vibrational energy harvesting
devices with sol-gel-derived lead zirconate titanate (PZT) as the active layer. Sol-gel-deposited
PZT typically suffers from lower piezoelectric constants than those from other deposition methods,
but it remains a simple method for depositing PZT films onto arbitrary wafer sizes and is a scalable
process. Several different cantilever geometries are explored in order to improve power output by
increasing the fraction of the material strained during deflection. Finite element analysis estimates
of the mechanical strain within these cantilevers, when driven at resonance, demonstrate that choice
of cantilever shape can significantly affect their power output.
The Mechanical Behaviour of Silicon Diaphragms for Micromachined Capacitive Pressure Sensor
Authors: Ren Juan , Cheneler David , Ward Mike , Kinnell Peter
Published: March 2009

Single crystal silicon diaphragms are widely used as pressure sensitive elements in
micromachined pressure sensors. When designing such a sensor it is usual to assume that the silicon is
an isotropic material and the average elastic constants are used. However, the mechanical properties
of single crystal silicon are orthotropic, and this has an important effect on the mechanical behaviour
of silicon diaphragms under pressure. In this work, the deflections of orthotropic silicon circular
diaphragms which are orientated against the (100) and the (110) planes are presented. It is found that
by assuming silicon is isotropic material, the maximum stress is underestimated by 9.4% for (110)
orientated silicon diaphragms, while the maximum stress is underestimated by 8% for (100)
orientated silicon diaphragms. Therefore, when a silicon diaphragm is used in a MEMS sensor, the
orthotropic properties should be taken into account for accuracy. Finally, the performance of a
capacitive sensor is predicted by using finite element method.
Thin Film YBCO Pixels for MMW Detector
Authors: Zakar Eugene , Wikner D. , Dubey Madan , Amirtharaj Paul
Published: March 2009

This research addresses the fabrication of crack-free 40-nm thin film YBa2Cu3O7 (YBCO) pixel
structures based on high temperature superconductor (HTSC) microbolometers for highly sensitive
thermal detectors that can be miniaturized for affordable passive millimeter-wave (MMW) imaging.
A completely dry etch process is described for suspended transition edge bolometers by removing
(releasing) the silicon substrate underneath a 3 micrometer wide pixel using gaseous plasma
sulfurhexafluoride (SF6) chemical reaction. This is an improvement over conventional selective wet
chemical etching techniques that are both harsh on the YBCO and require additional complex
alignment steps to the substrate material leading to very poor device yields and performance. Issues
relating to material roughness, etch redeposition, and silicon undercutting will be analyzed and
methodologies to overcome/minimize such problems will be explained in detail.
Micromask Generation for Polymer Morphology Control: Nanohair Fabrication for Synthetic Dry Adhesives
Authors: Sameoto Dan , Li Ya Song , Menon Carlo
Published: March 2009

Since early this decade, investigations into how geckos achieve their remarkable adhesive
properties, have determined that multi-scale compliant systems can allow geckos to attach to nearly
any surface through Van der Waals forces. Microscopic hairs on the bottom of gecko feet can make
intimate contact over large areas, and allows relatively weak Van der Waals forces to produce
significant adhesion on the macroscale. Over the past five years, microfabrication technology has
been used to replicate these multi-scale compliant mechanisms, using silicon or polymers to
reproduce microscale rods or cantilevers to produce what is known as a dry adhesive. What is more
difficult is creating the nanoscale compliant systems that create most contact areas in gecko feet.
This work examines how a well known problem in reactive ion etching processes, RIE "grass" can
be used to great effect to alter surface morphology on the nanoscale for nearly any polymer.
Identical etching parameters in the presence of different elements, like gold or aluminum, can result
in radically different surface morphologies and material behaviors, potentially allowing both
adhesive and non-adhesive areas to be formed in a single material. This technique is potentially the
easiest and fastest way to produce nano-compliant systems for use with dry adhesives.
Fabrication and Characterisation of MIS Organic Memory Devices
Authors: Mabrook Mohammed Fadhil , Kolb Daniel , Pearson Christopher , Zeze D.A. , Petty M.C.
Published: March 2009

There is a current upsurge in research on devices with nanoparticles embedded in
dielectrics. Such structures can operate as memories with high speed, high density, low voltage and
low cost. Here, we report on hybrid gold nanoparticle-based metal-insulator-semiconductor (MIS)
memory devices combining silicon technology and organic thin film deposition. The nanoparticles
are deposited using a self-assembly technique at room temperature onto a 4.5 nm thermal silicon
oxide layer. A 40 nm thin film of pentacene (deposited by flash thermal evaporation),
polymethylmethacrylate (spin coated) and cadmium arachidate (deposited using the Langmuir-
Blodgett technique) are used as insulators. Distinct capacitance-voltage (C-V) hysteresis is observed
with a memory window that increases linearly with increasing voltage programming range.
Clockwise and anticlockwise hysteresis in devices based on p-type and n-type silicon, respectively
are observed, indicating that charges are injected from the top electrode to the nanoparticles rather
than tunnelling through the thin SiO2 layer. However, thermal growth of SiO2 at a temperature
below 800 °C resulted in a hysteresis in the opposite direction. The detailed electrical behaviour of
the MIS devices will be discussed.
Electrically Re-Writable Non-Volatile Memory Device - Using a Blend of Sea Salt and Polymer
Authors: Salaoru Iulia , Paul Shashi
Published: March 2009

Intensive research is currently underway to exploit the highly interesting
properties of nano-sized particles and organic molecules for optical, electronic and other
applications. Recently, it has been shown that nano-sized particles and small organic molecules
embedded in polymer matrices can be used to realise memory devices. Such memory devices are
simple to fabricate via the spin-on technique. This work presents an attempt to use sea salt,
embedded in polyvinyl acetate, in the making of the memory devices. A polymer blend of polyvinyl
acetate and sodium chloride (NaCl) was prepared in methanol and spin coated onto a glass substrate
marked with thin Al tracks and a top contact was evaporated onto the blend after drying - this
resulted in a metal-organic-metal (MOM) structure. The current-voltage (I-V) behaviour of MOM
devices shows that the devices can be switched from a high conductivity state to a low conductivity
state, by applying an external electric field - this property can be exploited to store data bits. The
possible charging mechanism, based on the electric dipole formation, is presented in this work.
Polymer blends of polyvinyl acetate with nano-particles of BaTiO3 are also investigated to further
our understanding of charging mechanism(s).
Experimental and Theoretical Examination of the Phase Transfer from the Acoustic to Optical Waves during Strong Anisotropic Bragg Diffraction in Acousto-Optic Devices
Authors: Veress Mate , Maák P. , Richter P.
Published: March 2009

The optical phase of a beam diffracted in an acousto-optic interaction may be directly
controlled with the acoustic phase, but limitations occur in the case of commonly used AO devices,
based on strong anisotropic AO interaction. In our study we present measurement and theoretical
calculation of the phase shift of a laser beam diffracted in an AO deflector. The optical phase is a
function of the acoustic and optical frequency and of the relative spatial positions of the interacting
beams. We measured the phase shift with a heterodyne setup, where we measured the phase of the
heterodyne signal relative to a fixed reference. We found that the phase shift introduced by the AO
crystal is linear with the sound frequency, its gradient is of 10-20rad/MHz and depends mainly on
the optical beam's distance from the transducer. We show that this phase shift can be derived
theoretically from the momentum matching condition that must be fulfilled at each optical and
acoustic frequency pair.
Symmetrical Electrochromic and Electroemissive Devices from Semi-Interpenetrating Polymer Networks
Authors: Verge Pierre , Beouch Layla , Aubert Pierre Henri , Vidal Frederic , Tran-Van François , Teyssié Dominique , Chevrot Claude
Published: March 2009

This paper describes the elaboration and optical characterizations of electrochromic
devices (ECDs) based on a semi-Interpenetrating Polymer Network architecture. These ECD
exhibit contrast ration of 36% in the full visible range and are able to switch 10,000 times at
low voltage between +1.2V and -1.2V with only 0.2% of electroactivity lost. By the way,
these IPN-based materials present interesting properties in the NIR region.
Smart Windows
Authors: Granqvist Claes Goran
Published: March 2009

Electrochromic (EC) device technology can be used for modulating the transmittance of
visible light and solar radiation in windows in buildings as well as for other see-through
applications. This paper emphasizes the great energy savings that can be achieved in the built
environment, jointly with improved indoor comfort for the users of the building. Manufacturing
aspects are considered with particular focus on potentially low-cost methods possible to implement
with roll-to-roll technology. In particular the paper discusses recent work on foil-type devices
embodying sputter deposited WO3 and NiO-based films joined by a polymer electrolyte.
WO3 Thin Films Active in the IR Region
Authors: Sauvet Katherine , Sauques Laurent , Durand Olivier , Perrière Jacques , Ledeuil Jean Bernard , Gonbeau Danielle , Rougier Aline
Published: March 2009

This paper reports the enhancement of the electrochromic properties in the infrared, IR,
region of radio frequency sputtered WO3 thin films thanks to a careful optimization of the
deposition conditions. From the combination of various techniques of characterization, the optical
performances, in particular, the contrast in reflectance between the inserted state and the deinserted
one, upon cycling in H3PO4 liquid electrolyte, are correlated to the film morphology and
composition. Films, grown in higher chamber pressure, exhibiting a lower density and a O/W ratio
higher than 3, show the most promising behavior. Finally, first trends on the incorporation of the
WO3 single layer in full electrochromic devices are discussed.
Electroactive Pressure Sensors for Smart Structures
Authors: Martínez Fernando , Tynan E. , Arregui M. , Obieta G. , Aurrekoetxea J.
Published: March 2009

A hardware-software interface for smart electroactive pressure sensors has been designed
with the objective of providing a low power consumption and high performance impact monitoring
system, integrated in new smart structures. The interface is specifically designed for its use with
distributed pressure sensors based on conductive polymers. Their low cost and flexibility make
them suitable for placing on large surfaces. The smart sensor integrates a microprocessor, a radio
chip and a complete analog front end based on a period-modulated oscillator. The software
developed implements new interface applications for this hardware in TinyOS. The response of the
sensor, both loading and unloading, to different impact energies first, and then to different probe
stiffness is presented. The behaviour of the sensor to impact is also compared to the response in
static, and the different factors affecting the sensor response in both conditions are described.
Comparing and contrasting the sensor signal with that of an impact pendulum shows that the sensor
is suitable for measuring impact in both flexible and rigid structures.
Piezoelectric Sensor System for Structural Health Monitoring
Authors: Kim Byung Soo , Roh Yong Rae
Published: March 2009

This paper presents the feasibility of a sensor system consisting of piezoelectric oscillator
sensors to detect local damages and ultrasonic sensors to detect global damages in a structure. The
oscillator sensor is composed of a feedback oscillator circuit and a piezoceramic lateral mode vibrator
to be attached to a structure. Damage to the structure causes a change in the resonant frequency of the
vibrator, which is detected by the oscillator circuit. However, the response of the oscillator sensor is
limited to the area around the sensor, thus local measurement. The ultrasonic sensor generates Lamb
waves and the waves traveled over a long distance are received by another piezoceramic patch on the
structure. The received wave form reflects all the defects encountered during the propagation, thus
global measurement is possible. The two sensor types are combined as a sensor network, and its
operation system is developed as a portable unit for practical applicability.
Monitoring Prestress Level in Seven Wire Prestressing Tendons by Inter Wire Ultrasonic Wave Propagation
Authors: Bartoli Ivan , Salamone Salvatore , Phillips Robert , Lanza di Scalea Francesco , Coccia Stefano , Sikorsky Charles S.
Published: March 2009

Researchers at UCSD are investigating, in collaboration with Caltrans, the combination
of ultrasonic guided waves and embedded sensors as an approach to provide both prestress level
monitoring and defect detection capabilities in concrete-embedded PS tendons. This paper will
focus on the prestress level monitoring by first discussing the behavior of ultrasonic guided waves
propagating in seven-wire, 15.2-mm diameter twisted strands typically used in post-tensioned
concrete structures. A semianalytical finite element analysis is used to predict forced wave solutions
as a function of the applied prestress level. A feature shown sensitive to load levels is the inter-wire
energy leakage. In order to monitor such feature, piezoelectric sensors were experimentally
employed to probe the individual, 5-mm wires comprising the strand. Results of load monitoring in
embedded strands during laboratory tests will be presented and a statistical approach will be used to
enhance the evaluation of prestress loss in the strands.
A Vibration Exciter for Evaluating Cable Damping of a Cable-Stayed Bridge
Authors: Kim Jae Min , Lee Jong Jae , Ahn Sang Sup , Choi Jun Seong
Published: March 2009

It is necessary to accurately estimate the dynamic characteristics of stay cables, especially
damping ratios, to design cable damper for appropriate vibration mitigation of a cable-stayed bridge
in service. In this study, a vibration exciter has been developed to evaluate the cable damping of a
cable-stayed bridge. The feasibility of the developed system was verified through field tests on a
100m long stay cable. The damping ratios of the stay cable were estimated based on acceleration data
as well as displacement data measured by digital image processing technique. The performance of the
passively operated MR dampers with the different voltage inputs were investigated by comparing the
estimated damping ratios.
Ride Comfort Analysis of a Full-Vehicle Featuring Magnetorheological Shock Absorbers
Authors: Sung Kum Gil , Choi Seung Bok
Published: March 2009

This paper presents ride comfort analysis of a full-vehicle featuring controllable
magnetorheological (MR) shock absorbers. In order to achieve this goal, two flow mode MR shock
absorbers (one for front suspension; one for rear suspension) are designed using an optimization
methodology based on design specifications for a commercial passenger vehicle. The optimization
problem is to find optimal geometric dimensions of the magnetic parts for the front and rear MR
shock absorbers in order to improve the performance such as damping force. After manufacturing the
proposed MR shock absorbers, their field-dependent damping forces are experimentally evaluated.
The governing equation of motion for the full-vehicle is then established and integrated with the
model of the MR shock absorbers. Subsequently, skyhook controllers for the MR suspensions are
formulated and implemented. Ride comfort performances of the full-vehicle installed with the
proposed MR shock absorbers are evaluated under bump and random road.
Fault Tolerant Neural Aided Controller for Multi Degree of Freedom Structures Experiencing Online Sensor Failure
Authors: Contreras Michael , Nagarajaiah Satish , Narasimhan Sriram
Published: March 2009

This study validates an adaptive control algorithm capable of compensating for online
sensor failure. Online failure is a relevant problem when considering actively damped, multi-story
smart buildings experiencing a disturbance event. In recent years, Artificial Neural Networks
(ANNs) have proven very efficient in pattern classification and control applications. In this study,
the unique application of ANNs involving Radial Basis Functions (RBFs) combined with H∞
optimal control has demonstrated three significant characteristic advantages: (1) real time
adaptability, (2) optimal convergence and computation time, and (3) most importantly, no offline
training. The novelty of the proposed controller is elucidated by performing disturbance rejection
tests involving a scaled two degree of freedom shear frame subjected to a combined H∞ and ANN
control. A bench scale structural model is instrumented with piezoelectric sensors and actuators.
After the onset of a first mode disturbance, the structural frame is subjected to a complete sensor
failure. The proposed controller is shown to enhance the performance of a baseline H∞ controller
in the presence of sensor failure.
Current Directions of Structural Health Monitoring and Control in USA
Authors: Nagarajaiah Satish , Dyke Shirley , Lynch Jerome P. , Smyth Andrew , Agrawal Anil , Symans Michael , Johnson Erik
Published: March 2009

Structural Health Monitoring (SHM) is an important and growing field in civil engineering. The
goal of SHM techniques is to identify, quantify and locate damage in structures. In light of the aging infrastructure
and recent failures of important bridges, long-term monitoring techniques are being increasing investigated
and adopted. In addition to SHM, structural control (SC) is increasingly adopted in modern structures around
the world. In the past two decades a number of SC techniques, including, passive, semi-active, and active
control methods have been developed and adopted in civil engineering–particularly, in infrastructure such as
important tall buildings, critical facilities, and long span bridges. Both SHM and SC technology face significant
challenges due to the size and scale of civil engineering structures. In response of these challenges researchers
in the U.S.A and around the world have developed new and innovative techniques.This paper summarizes some
of the ongoing research in the U.S.A. in the area of monitoring, damage detection and control in civil engineering
structures.
Experimental Investigation of Effectiveness of Smart Passive System for Seismic Protection of Building Structures
Authors: Jung Hyung Jo , Jang Dong Doo , Lee Heon Jae , Moon Seok Jun
Published: March 2009

The newly developed smart passive system is based on a magnetorheological fluid (MR)
damper, which is one of the most promising semiacitve control devices, and an electromagnetic
induction (EMI) part, which is a power harvesting device from vibration of a structure according to
Faraday’s law of electromagnetic induction. Numerical simulations recently conducted by the
authors have verified that the smart passive system could be effective to reduce the structural
responses in the cases of civil engineering structures such as buildings and bridges. On the other hand,
the experimental validation of the system is not sufficiently carried out yet. In this study, therefore, a
series of shaking table tests are conducted to experimentally investigate the effectiveness of the smart
passive system for seismic protection of building structure. The model structure is a scaled six-story
frame structure with the height of 3.5 m and the weight of about 8 ton. The smart passive system is
installed between its base floor and the first floor. The responses of the structure are measured under
several ground motions including scaled historic earthquake records. The preliminarily experimental
results in the smart passive system case are compared with those in the MR damper-based semiactive
control cases.
Modeling and Identification of a Large-Scale Magnetorheological Fluid Damper
Authors: Rodriguez Arturo , Iwata N. , Ikhouane Fayçal , Rodellar José
Published: March 2009

In the last years there has been an increasing interest to magnetorheological (MR)
dampers and their applications to civil engineering. In particular they have been used as semi-active
control devices for vibration mitigation due to external dynamic loads. These devices are highly
nonlinear and thus accurate models of these devices are important for effective simulation and
control system design. Two hysteretic models based on the normalized Bouc-Wen model are
proposed in this paper to compare their effectiveness in a large scale MR fluid damper. A
methodology for identification is proposed, and the obtained models are tested and validated
experimentally.
Characterisation of Force-Deflection Behaviour of Piezoelectrically Actuated Bistable Composite Laminate under Two-Axis Constraint
Authors: Giddings Peter F. , Bowen Chris R. , Kim H.A.
Published: March 2009

This paper characterises the properties of unsymmetric bistable carbon fibre composites
actuated using a single piezoelectric macro fibre actuator. A piezoelectric–laminate combination
under two-axis constraint was evaluated in terms of its load–deflection characteristics, snap-through
force and stiffness. The load–deflection characteristics indicate that snap-through force and laminate
stiffness increase as a function of piezoelectric actuator drive-voltage. Both snap-through force and
laminate stiffness are significantly increased under two-axis constraint, as compared to single-axis
constraint. Snap-through force and stiffness are shown to be affected by localised curvature
variation caused by laminate ageing.
Software Development Modules for Microcontroller-Based System
Authors: Edmondson Michael C. , Tang L. , Kern A.
Published: March 2009

Microcontrollers are small devices commonly used for control purposes over a wide
range of applications. As the control strategies and the selection of hardware differ from one
application to another, it is a common practice for engineers to develop the application programs
based-on the selected hardware and the control methodologies. Such development process requires
time for programming and testing, especially for large projects which need to interface and integrate
with a number of different hardware and software. This paper presents an approach using the
concept of soft development modules to shorten the application program development time for
control systems using microcontrollers. A set of soft modules has been developed for a widely used
microcontroller. The testing conducted on the serial communication and fuzzy logic control
modules successfully produced application programs within a much shorter time, and reduced
human programming errors. The application of soft development modules will allow system
developers to focus on the system design level without the need to spend large amount of time on
generic programming details. Such an approach provides a useful programming development
platform for future applications using microcontrollers.