bluuebunny/crossref_metadata_2025 huggingface dataset:
Phase Field Dynamic Modelling of Shape Memory Alloys Based on Isogeometric Analysis
Authors: Dhote Rakesh , Gomez Hector , Melnik Roderick , Zu Jean
Published: September 2012

Shape Memory Alloys (SMAs) exhibit complex behaviors as a result of their constituent phases and microstructure evolution. In this paper, we focus on the numerical simulations of microstructure evolution in SMAs using a phase-field model for the two dimensional square-to-rectangular martensitic phase transformations. The phase-field model, based on the Ginzburg-Landau theory, has strong non-linearity, thermo-mechanical coupling, and higher-order differential terms and presents substantial challenges for numerical simulations. The isogeometric analysis, developed in this paper using the rich NURBS basis functions, offers several advantages in solving such complex problems with higher-order partial differential equations as the problem at hand. To our best knowledge, we report here for the first time the use of the new method in the study of microstructure evolution in SMAs. The numerical experiments of microstructure evolution have been carried out on the FePd SMA specimen. The results are in good agreement with those previously reported in the literature.
Effect of Repeated Heat-Treatment under Constrained Strain on Mechanical Properties of Ti-Ni Shape Memory Alloy
Authors: Cho Hiroki , Yamamoto Takaei , Suzuki Akihiko , Sakuma Toshio , Yamauchi Kiyoshi
Published: September 2012

It is well-known that the Ti-Ni shape memory alloy (SMA) is applicable to the medical stent. The repeated heat-treatment under the constrained strain is necessary for the manufacturing process of the laser-cut SMA stent. In this research, the effect of heat-treatment under the constrained strain on mechanical properties of the Ti-Ni shape memory alloy wire was investigated. The applied strain at single heat-treatment (εap) was 4, 5 and 8%, and the heat-treatment is repeated so as to became total applied strain 40%. In the case of εap=4 and 5%, partial transformation occurs in the SMA wire, and so a necking appears in the SMA wire. Due to this necking, multi-step martensitic transformation, and decreasing of breaking strength / breaking strain are caused. The necking does not occur because the whole of the SMA wire is transformed for εap=8%. The mechanical properties are improved by increasing of εap. Nevertheless, the mechanical properties of each sample are inappropriate for the medical stent. However, the mechanical properties of the as-manufactured sample are improved greatly by training. In addition, it is desirable that the applied strain during training is slightly larger than the requested strain for application.
Digital Image-Based Method for Quality Control of Residual Bending Deformation in Slender Pseudoelastic NiTi Devices
Authors: Viscuso Stefano , Garavaglia Lorenzo , Pittaccio Simone
Published: September 2012

Pseudoelastic NiTi-based devices are often required to recover their shape repeatedly and their working performance can be judged from the amount of residual deformation after use. The quality problem in this respect can even be removed from fatigue life or safety issues and impact on the functional and aesthetic value of the product. While linear deformation can be appreciated quantitatively in a straightforward manner, the bending strains are more difficult to assess directly. We devised a very simple digital image-based method to measure the residual bending deformation by comparison of the pristine shape of the device with the one resulting from bending and free recovery. The program was written in LabView and is capable of reporting about the deflection and location of strain concentration along slender pseudoelastic elements in a semi-quantitative way appropriate for quality sample checks. The method is semi-automatic and provides a user-friendly interface for the operator. Apart from simple shapes like straight wires and ribbons, the method was tested on devices as complex as spectacles frames. This application is particularly interesting, where shape recovery and functional and aesthetic value are tightly linked, and deformation by severe handling is a typical effect of use.
Parametric Control of IPMC Actuator Modeled as Fractional Order System
Authors: Caponetto Riccardo , Graziani Salvatore , Pappalardo Fulvio , Xibilia Maria Gabriella
Published: September 2012

IPMC actuators suffer because of a large number of influencing factors that do not allow adequate open loop working conditions and they require the use of controlling strategies. IPMC controllers can be designed by using suitable device models. Here a non integer order transfer function is used to model IPMC actuators. In the present paper the IPMC model is scaled as a function of the actuator length and the control law has been parameterized according to this physical parameter
Synthesis of Stable Polypyrrole and Polyaniline Nanospheres
Authors: Suryawanshi Abhijit J. , Lamb Jessica , Gelling Victoria J.
Published: September 2012

One of the major obstacles associated with the synthesis of conducting polymer nanoparticles in water is their unstable nature, which is traditionally overcome through the use of soft or hard templates. Such methods use expensive surfactants, often in large amounts, and require the removal of the template, which adds complexity, expense, and environmental hazard. This study explores a facile, one-pot synthesis of stable polypyrrole and polyaniline nanospheres in water that uses ozone as the oxidant. Multiple variables were investigated in order to study the mechanism of this reaction, including monomer concentration, ozone exposure time, reaction temperature, pH, and the solvent system. Particle size measurements revealed that the size of the nanospheres, ranging from 50 nm to 500 nm in diameter, can be controlled via these reaction conditions. These self-stabilizing nanospheres were also characterized using Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV-Vis), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and zeta potential.
Functional Characterisations of Hybrid Nanocomposite Films Based on Polyaniline and Carbon Nanotubes
Authors: de Riccardis M. Federica , Martina V. , Carbone Daniela , Rotolo Paolo
Published: September 2012

The combination of nanoparticles and conducting polymers, known as hybrid conducting nanocomposites, is a new emerging field. The combination of conductive polymers, such as polyaniline (PANI), with conductive carbon nanotubes (CNTs) has already shown some synergistic properties. As a consequence, they have a variety of applications, such as sensors, actuators, touch screens, etc.. Usually PANI and CNTs are combined by using electrochemical synthesis starting with the monomer aniline. In this work PANI-CNTs nanocomposite films were obtained by using different combinations of two methods, Electrochemical Deposition (ELD) and Electrophoretic Deposition (EPD). The samples prepared by using these combined methods were compared with the material prepared by the usual electrochemical synthesis. Therefore, all the films so prepared were characterised and their electrochemical properties were investigated, particularly for evaluating their use as supercapacitor components.
Smart Textiles with Biosensing Capabilities
Authors: Pasche Stéphanie , Schyrr Bastien , Wenger Bernard , Scolan Emmanuel , Ischer Réal , Voirin Guy
Published: September 2012

Real-time, on-body measurement using minimally invasive biosensors opens up new perspectives for diagnosis and disease monitoring. Wearable sensors are placed in close contact with the body, performing analyses in accessible biological fluids (wound exudates, sweat). In this context, a network of biosensing optical fibers woven in textile enables the fabric to measure biological parameters in the surrounding medium. Optical fibers are attractive in view of their flexibility and easy integration for on-body monitoring. Biosensing fibers are obtained by modifying standard optical fibers with a sensitive layer specific to biomarkers. Detection is based on light absorption of the sensing fiber, placing a light source and a detector at both extremities of the fiber. Biosensing optical fibers have been developed for the in situ monitoring of wound healing, measuring pH and the activity of proteases in exudates. Other developments aim at the design of sensing patches based on functionalized, porous sol-gel layers, which can be deposited onto textiles and show optical changes in response to biomarkers. Biosensing textiles present interesting perspectives for innovative healthcare monitoring. Wearable sensors will provide access to new information from the body in real time, to support diagnosis and therapy.
Respiratory Volume Estimation by a Stretchable Textile Sensor
Authors: Enokibori Yu , Ito Yoshu , Ikeda Koji , Suzuki Akihisa , Shimakami Yuuki , Kawabe Tsutomu , Mase Kenji
Published: September 2012

E-Textiles using fabric sensors have been studied well for respiration monitoring in recent years; they can estimate respiratory rates and patterns. However, studies of respiratory volume and flow estimation remain unestablished, although they are necessary for the inspection and monitoring of chronic obstructive pulmonary disease (COPD). In this paper, we introduce a new stretchable textile sensor and examine how to calculate respiratory volume. The sensor can stretch up to about 150% (e.g., 13 to 20 cm). The stretch can be detected from the electronic potential changes between conductive fibers. We analyzed the relationships between the respiratory volume and the torso-surface movements using motion capture. In our evaluation, the mean rooted mean standard errors (RMSEs) of the estimated volumes were 0.39 ± 0.17 (L) among four datasets with motion capture and 0.62 ± 0.22 (L) among three datasets with the textile sensor. In addition, we successfully drew a similar flow volume curve (FVC) to those captured with a spirometer.
Integration of OLEDs in Textiles
Authors: Janietz Silvia , Gruber Björn , Schattauer Sylvia , Schulze Kerstin
Published: September 2012

In place of silicon, which is normally used in microelectronics, organic materials offer the opportunity to produce devices on large area, low-cost and plastic planar substrates. These materials are attracting increased attention also in the field of electronic-textiles (e-textiles) because they show an interesting combination of electronic and mechanical properties that can be favourably exploited in smart textiles. A key step for the integration of mass production of e-textiles is to combine electronic production with textile manufactures. In the last years, progress has been achieved in the development of fibers and their processing for application in e-textiles. The application ranged from fabric integrated light sources to low cost solid state lighting for protection and security. Here research results are presented regarding the integration of encapsulated glass OLEDs and additionally OLEDs fabricated on flexible high barrier substrates which were integrated into textiles. On the other hand, the first results concerning the realization of an OLED on cylindrical surfaces based on solution processed technologies which is a first step in the direction of low cost processing will be discussed. A simple, inverted planar construction prepared from solution was realized. This preliminary work was the precondition for the development of a fiber based OLED. In addition, OLEDs that were prepared using glass fibers as substrates and solution processed active and hole-transport layers will be shown.
Development of Piezoresistive Fiber Sensors, Based on Carbon Black Filled Thermoplastic Elastomer Compounds, for Textile Application
Authors: Clemens Frank J. , Koll B. , Graule T. , Watras T. , Binkowski M. , Mattmann C. , Silveira I.
Published: September 2012

For the development of piezoresistive sensor fibers compounds based on thermoplastic elastomer (TPE) matrix and electrical conductive carbon black powder was used. In this paper the fabrication of piezoresistive fibers by using thermoplastic extrusion method will be demonstrated. With the thermoplastic processing route (e.g. melt spinning process) smart functional senor fibers with a diameter of 300 µm where produced. Their dynamic and static electrical conductive properties where investigated by using a cycling mechanical tensile test in combination with conductive measurement. Compounds of three different SEBS type TPEs and compounds with different content of carbon black were used to investigate the influence on the drift and shift of the electrical signal during dynamic and static strain exposure. By changing the SEBS-Block copolymer matrix and by increasing the carbon black content above 45 wt% stable electrical signal with low relaxation behavior can be achieved.
The Power Conversion Characteristics of Woven Organic Photovoltaic Wire Fabrics
Authors: Agrawal Anshul , Kim Yong K. , Calvert Paul D. , Lee Michael
Published: September 2012

Recently there has been growing interest in developing smart photovoltaic fabric devices. These devices could be used as a sustainable and ubiquitous power source for wearable and other electronic devices. Three woven photovoltaic fabric structures were constructed with fiber-shaped organic photovoltaic wire from Konarka Technologies, Inc. (Lowell, MA, USA). The organic photovoltaic wire is a flexible, lightweight and wire shaped organic photovoltaic fiber based on bulk hetero-junction nanocomposites. The power conversion characteristics of photovoltaic fabrics developed were thoroughly investigated. It was found that the power conversion efficiency of the photovoltaic fabric depends on the incident light quality; fabric cover factor, swatch size, and fabric weave structure. This study also includes photovoltaic fabric model for understanding the effects of different fabric geometry on power conversion efficiency of photovoltaic fabrics. The model predicts the performance of the photovoltaic fabrics with different shape, size and structures, and it provides design criteria for more efficient photovoltaic fabric device.
Design and Optimization of an Injection-Moldable Force-Fit Interconnection Module for Smart Textile Applications
Authors: Simon Erik P. , Fröhlich Moritz , Kallmayer Ch. , Lang K. D.
Published: September 2012

This work presents a polymer based force-fit interconnection module (Click-Bond) that can be used to establish reliable electrical and mechanical interconnections between electronic components and textile circuit boards at room temperature. It is an extremely fast and cost-efficient process that is able to bring smart textile applications into the mass market. The semi-crystalline polymer POM-C is selected as material. It has good physical properties and can be used in injection molding. After the design is made mechanical experiments are performed to analyze the maximum forces and stress relaxation of the modules. Additionally, the compressibility of fabrics is analyzed to be able to design the module to apply a certain pressure. Finally, a multi-terminal board is presented that allows to easily integrate more complex electronics boards into smart textiles.
Wet-Etching Characteristics of SiCN Films Deposited by HWCVD Method
Authors: Nakanishi H. , Ogata T. , Kadotani Y. , Izumi Akira
Published: September 2012

We investigated the wet-etching properties of SiCN films using chemical agents. Our results show that sodium hydroxide, potassium hydroxide and phosphoric acid etch SiCN films, while hydrochloric acid, sulfuric acid, acetic acid, ammonium chloride and sodium chloride cannot etch SiCN films.
Modeling of Piezo-Actuated Stick-Slip Micro-Drives: An Overview
Authors: Nguyen Ha Xuan , Edeler Christoph , Fatikow Sergej
Published: September 2012

This paper gives an overview about problems of modeling of piezo-actuated stick-slip micro-drives. It has been found that existing prototypes of such devices have been investigated empirically. There is only few research dealing with the theory behind this kind of drives. By analyzing the current research activities in this field, it is believed that the model of the drive depends strongly on the friction models, but in most cases neglecting any influences of the guilding system.These analyses are of fundamental importance for an integrated model combining friction model and mechanical model offering promising possibilities for future research.
Foreign Bodies – The Creation of Symbiotic Jewellery through the Development and Application of Stimulus-Responsive Smart Materials and Microelectromechanical Systems
Authors: Vones Katharina
Published: September 2012

With the increased prevalence of digital technologies in our everyday lives, the questions posed to the contemporary craft practitioner regarding creation of an emotionally resonant interaction between the digitally enhanced object and its wearer have become progressively more prominent in the applied arts. Through examining the notion that human biology is a part of material culture, where the body can be shaped, customised or altered through surgical intervention and scientific innovation, this extended abstract explores how recent developments in material science and wearable technologies can be viewed as contiguous rather than oppositional to the organic processes of the human body and how to bridge the gap between the craft practitioner and scientific discovery. More immediately however, this research project challenges the perception of smart materials and their application within the field of contemporary jewellery in both an artistic and scientific context through proposing the development of symbiotic stimulus-reactive jewellery organisms. Potential practical applications of these jewellery objects exist in the areas of human–computer interaction, transplant technology, identity management and artificial body modification including prosthetics, where such symbiotic jewellery organisms could be used to develop visually engaging yet multifunctional enhancements of the body.
Functional RF Devices Powered by MEMS Technologies
Authors: Hashimoto Ken Ya , Hirano Hideki , Tanaka Shuji , Esashi Masayoshi
Published: September 2012

This paper discusses use of MEMS technologies in radio frequency (RF) frontend. First, configuration of RF front-end in current wireless communication systems is surveyed, and research trends of the flexible RF front-end and software defined radio (SDR) are discussed. Second, various RF tunable filters are introduced, and we discuss how high performances are expected by the use of tunable RF surface and bulk acoustic wave (SAW/BAW) filters provided that above mentioned key technologies are developed. Finally, our attempts for realization of tunable RF SAW/BAW filters are introduced.
Gas Cluster Ion Beam Technology for Nano-Fabrication
Authors: Toyoda Noriaki , Yamada Isao
Published: September 2012

A gas cluster is an aggregate of a few to several thousands of gaseous atoms or molecules, and it can be accelerated to a desired energy after ionization. Since the kinetic energy of an atom in a cluster is equal to the total energy divided by the cluster size, a quite-low-energy ion beam can be realized. Although it is difficult to obtain low-energy monomer ion beams due to the space charge effect, equivalently low-energy ion beams can be realized by using cluster ion beams at relatively high acceleration voltages. Not only the low-energy feature but also the dense energy depositions at a local area are important characteristics of the irradiation by gas cluster ions. All of the impinging energy of a gas cluster ion is deposited at the surface region, and this dense energy deposition is the origin of enhanced sputtering yields, crater formation, shockwave generation, and other non-linear effects. GCIBs are being used for industrial applications where a nano-fabrication process is required. Surface smoothing, shallow doping, low-damage etching, trimming, and thin-film formations are promising applications of GCIBs. In this paper, fundamental irradiation effects of GCIB are discussed from the viewpoint of low-energy irradiation, sputtering, and dense energy depositions. Also, various applications of GCIB for nano-fabrications are explained.
Electric Field Dependence of Molecular Orientation and Anisotropic Magnetic Interactions in the Ferroelectric Liquid Crystalline Phase of an Organic Radical Compound by EPR Spectroscopy
Authors: Suzuki Katsuaki , Uchida Yoshiaki , Tamura Rui , Noda Yohei , Ikuma Naohiko , Shimono Satoshi , Yamauchi Jun
Published: September 2012

To confirm whether chiral organic radical compound 1, which showed the generation of a sort of spin glass-like inhomogeneous ferromagnetic interactions (the average spin-spin interaction constant J > 0) in the bulk liquid crystalline state under weak magnetic fields, has a spin easy axis or exhibits anisotropic magnetic interactions in the SmC* or SmC phase, we have measured the temperature dependence of g-value and relative paramagnetic susceptibility (χrel) for the ferroelectric SmC* phase of (2S,5S)-1 confined in a thin sandwich cell by EPR spectroscopy.
Adaptive Optical Systems in Russian Federal Nuclear Center - VNIIEF with Different Control Principles
Authors: Garanin Sergey , Khokhlov Sergey , Manachinsky Aleksei , Starikov Fedor
Published: September 2012

We report the results of performance of closed-loop adaptive optical systems intended for phase correction of pulsed and cw laser beams. The conventional control of adaptive system is based on wavefront sensing (e.g., Hartmann-Shack) and following deformation of adaptive mirror surface. We demonstrate the results of such static phase correction in the cases of the vortex laser beam and the powerful laser beam of pulsed “Luch” facility. On other side, applying the sensor-less approach we perform the dynamic phase correction of tip-tilts and higher phase aberrations of laser beams using the stochastic parallel gradient algorithm embedded into the special control units with microcontroller that considerably broadens the system operation bandwidth.
Passive and Active Nanophotonics
Authors: Fainman Yeshaiahu , Tan D. , Zamek S. , Bondarenko O. , Simic A. , Mizrahi A. , Nezhad M. , Lomakin V. , Gu Q. , Lee J. , Khajavikhan M. , Slutsky B.
Published: September 2012

Dense photonic integration requires miniaturization of materials, devices and subsystems, including passive components (e.g., engineered composite metamaterials, filters, etc.) and active components (e.g., lasers, modulators, detectors). This paper discusses passive and active devices that recently have been demonstrated in our laboratory, including monolithically integrated short pulse compressor utilized with silicon on insulator material platform and design, fabrication and testing of nanolasers constructed using metal-dielectric-semiconductor resonators confined in all three dimensions.
High Precision Adaptive Space Structures
Authors: Baier Horst
Published: September 2012

Integrated actuators and sensors promise significant improvement in structural performance if not being an essential condition for high functionality. But “integration” per se is no added value. For example, actuators have to be sufficiently small and local weakening of the material has to be avoided. So such concepts are specifically apt for actuating and controlling small displacements or low mass / low damping vibrating systems e.g. in opto-mechanical systems or space structures such as large reflectors, solar arrays or telescopes. For large reflectors with high dimensional stability requirements, post-manufacturing improvement of shape accuracy or a certain compensation of in-orbit disturbances is of interest. A further challenge comes into play when such structures have to be drastically morphed in their shapes in order to adapt to modified mission needs, which then calls for micro-actuators with relatively large displacement strokes. The discussion of these aspects will be based on results derived from simulations as well as from laboratory models.
Smart Composite Device for Structural Health Monitoring
Authors: Coricciati Angela , Corvaglia Paolo , Largo Alessandro , Caponero Michele Arturo
Published: September 2012

Composite materials are increasingly used in civil field for structural strengthening. Besides, monitoring the structure during its lifetime is very important, in order to detect possible anomalous situations and to reduce maintenance and inspection costs. Optical fibers represent a promising and increasingly used technique for long-term health monitoring of structures. The aim of this research is to assess the feasibility and reliability of strain measurements by utilizing FBG (Fiber Bragg Grating) optical sensors embedded in FRP (Fiber Reinforced Plastic) packaging. The resulting device is conceived to be applied on the external surface of the structure. The packaging provides the optical fiber with the necessary protection against accidental damage during handling and installation. The mechanical characteristics of the packaging allow the device to be used as a sensorised reinforcement as well. The paper discusses the technology set-up, the physical and the mechanical characterization of the developed smart device.
Structural Health Monitoring of a Tall Building with Huge Floating Platform
Authors: Ni Yi Qing , Xia Y.X. , Ye Xiao Wei
Published: September 2012

The New Headquarters of Shenzhen Stock Exchange (NHSSE), located in Shenzhen, China, is a high-rise building with a height of 228 m. One salient feature of NHSSE is its huge floating platform. It is a steel truss structure assembled with a total of 14 steel trusses in six types. It overhangs from the main tower 36 m along the long axis and 22 m along the short axis at a height of 36 m above the ground. As a result, the huge floating platform has an overall plan dimension of 98 m × 162 m and a total height of 24 m, making it one of the largest cantilever structures in the world. In view of the uniqueness of the floating platform, a long-term structural health monitoring (SHM) system has been designed and implemented on NHSSE by The Hong Kong Polytechnic University. In this monitoring system, the strain and deflection of the cantilever structure are of the utmost concern. A total of 224 vibrating-wire strain gauges have been installed to measure the strain and a novel vision-based displacement tracking system has been employed to monitor the deflection. In addition, accelerometers and a wireless sensing network (WSN) are implemented to monitor dynamic responses and modal properties of the structure. This paper reports the monitoring results of stress evolution of NHSSE during the construction process of dismantling the shoring and modal properties of NHSSE under ambient vibration environment, as well as their comparison with the prediction results through finite element analysis.
A Comparative Assessment of Two SHM Damage Detection Methods in a Laboratory Tower
Authors: Zugasti Ekhi , Gonzalez Ana Gomez , Anduaga Javier , Arregui Miguel Angel , Martínez Fernando
Published: September 2012

In the present paper, we introduce an application of two damage detection methods to a laboratory structure. One of the methods is based on autoregressive modeling of the signals involved, whereas the second one is based on subspace identification. Both have been tested in a tower that simulates a wind turbine. The results obtained are correct for the damages simulated by loosening some bolts of the different joints. The results show that the second method is computationally more efficient whereas the results are more stable in the first one.
A Mathematical Framework for Structural Control Integration
Authors: Rossell Josep M. , Rodellar José , Palacios-Quiñonero Francisco , Rubió-Massegú Josep
Published: September 2012

In this paper, some control strategies to design decentralized controllers are developed and discussed. These strategies are based on the Inclusion Principle, a very useful mathematical framework to obtain decentralized controllers, mainly when the systems are composed by overlapped subsystems sharing common parts. A five-story building model serves as example to show the advantages provided by this approach. Numerical simulations are conducted to assess the performance of the proposed control laws with positive results.
A Fractal-Inspired Multi-Frequency Piezoelectric Energy Converter: Design and Experimental Characterization
Authors: Castagnetti Davide
Published: September 2012

A promising harvesting technique, in terms of simplicity and efficiency, is the conversion of ambient kinetic energy through piezoelectric materials. This work aims to design and investigate a piezoelectric converter conform to a fractal-inspired, multi-frequency structure previously presented by the author. A physical prototype of the converter is built and experimentally examined, up to 120 Hz, in terms of modal response and power output. Three eigenfrequencies are registered and the power output is particularly good at the fundamental eigenfrequency. Also the effect of the resistive load applied to the converter is investigated.
Seismic Protection of Structures Using Tuned Mass Dampers with Resettable Variable Stiffness
Authors: Lin Chi Chang , Soong Tsu Teh
Published: September 2012

Vibration control of civil engineering structures using tuned mass dampers (TMD) is a widely accepted control strategy after numerous analytical and experimental verifications. Although the design and application of traditional linear TMD systems are well developed, nonlinear TMD systems that may lead to better control performance are still in the developmental stage. There are two main problems associated with TMD systems, i.e. (1) detuning effect and (2) excessive stroke of TMD. In order to improve the performance of TMD systems, a novel semi-active TMD named resettable variable stiffness TMD (RVS-TMD) is proposed in this study. The RVS-TMD consists of a TMD and a resettable variable stiffness device (RVSD). The RVSD is composed of a resettable element and a controllable stiffness element. By varying the stiffness element of the RVSD, the force produced by the RVSD can be controlled smoothly through a semi-active control law. By resetting the resettable element, the hysteresis loop of the RVSD can cover all four quadrants in the force-deformation diagram and thus results in more energy dissipation. The harmonic and seismic responses of a building equipped with the RVS-TMD are investigated numerically and compared with those by its active control counterpart and an optimal passive TMD system. The results show that the proposed RVS-TMD system has good control performances as its active control counterpart and is able to alleviate detuning effect and reduce TMD’s stroke.
Use of Textile Friction to Mimic Hill's Model in Dynamic Contraction of Braided Artificial Muscles
Authors: Tondu Bertrand
Published: September 2012

Several types of artificial muscles are actually able to mimic the active spring-like behaviour characterizing the tension-length diagram of the skeletal muscle but the natural damping expressed by the typical tension-velocity Hill’s relationship is not so easy to integrate in a simple way into the artificial muscle functioning. We discussed the use of a textile braided sheath, particularly in the case of the so-called McKibben structure to obtain a Hill’s model-like dynamic behaviour of the artificial muscle. Experiments are reported to compare “quick-release” experiments – as defined in muscular physiology – between artificial muscles whose braided weave is made of metallic strands and of rayon textile strands. It is shown that only in the second case a typical hyperbolic tension-velocity is highlighted with a curvature close to this of human skeletal muscle. It is also shown how the typical laws of friction in textile can explain this analogical behaviour with the Hill’s-model interpreted as a force model including a typical non-linear viscous component. An original interpretation of Hill’s model in terms of natural load-variations adaptation is given and so the advantage for an artificial muscle to get this biomimetic character.
Bio-Inspired Active Electrolocation Sensors for Inspection of Tube Systems
Authors: Gottwald Martin , von der Emde Gerhard
Published: September 2012

At night, weakly electric fish Gnathonemus petersii use active electrolocation to scan their environment with self generated electric fields. Nearby objects distort the electric fields and are recognized as electric images on the electroreceptive skin surface of the animal. By analyzing the electric image, G. petersii can sense an object’s distance, dimensions and electrical properties. The principles and algorithms of active electrolocation can be applied to catheter-based sensor systems for analysing wall changes in fluid filled tube systems, for example atherosclerotic plaques of the coronary blood vessels. We used a basic atherosclerosis model of synthetic blood vessels and plaques, which were scanned with a ring electrode catheter applying active electrolocation. Based on the electric images of the plaques and the evaluation of bio-inspired image parameters, the plaque’s fine-structure could be assessed. Our results show that imaging through active electrolocation principally has the potential to detect and characterize atherosclerotic lesions.
Mimicking Bone Architecture in a Metallic Structure
Authors: Goia Tamiye Simone , Violin Kalan Bastos , Bressiani José Carlos , Bressiani Ana Helena de Almeida
Published: September 2012

The porous metallic structure has been developed to mimic the natural bone architecture, having interconnected porosity, disposing enough room to cell migration, anchoring, vascularization, nourishing and proliferation of new bone tissue. The titanium is used as porous implants due its excellent mechanical properties and biological interaction. Research evolving porous titanium has been done with purpose to achieve desirable pore size, total porosity percentage and influence of those in the increasing of bone-implant bond strength interface. Were prepared samples of titanium by powder metallurgy adding natural polymer: corn starch, rice starch, potato starch and gelatin; at proportion of 16 wt%. In aqueous solution the hydrogenated metallic powder (TiH2) and the polymer were mixed, homogenized and frozen in molds near net shape. The water was removed in kiln (38°C/12h) and the polymer by thermal treatment with air-oxidation (350 °C/1h) before sintering in high-vacuum (1300 °C/1h). Resulting from the process, the obtained pores by addition of potato and corn starchs, lead to homogenous and well distributed throughout structure. Samples obtained from addition of rice starch and gelatin formed macropores and micropores randomly distributed within the structure. The apparent porosity for all samples was near 40%. The processing technique allowed the open pore formation, in which the macropores mimics the trabecular bone structure and micropores allows the bone-implant anchorage.
A Novel Wearable System for Elderly Monitoring
Authors: Faetti Tommaso , Paradiso Rita
Published: September 2012

The average age of European population is growing year by year and the social impact of this trend will affect the future economy of developed countries. Since elderly people suffer from many chronic diseases that limit their capabilities; home assistance is one of the main emerging needs. One common aspect of advanced age is susceptibility to hypothermia due to several age-related physiological factors such as lower metabolism, thinner skin, malnutrition, and delayed perception of hot/cold. Hypothermia can lead to mortality during the night in elderly affected by diseases or disabilities. In this paper we present a pajama that aims to monitor elderly people while sleeping. Such a system, developed in the scope of EU funded project MOBISERV, is able to monitor a 1 lead ECG signal, upper body movements and skin temperature from 2 different sites through a distributed Body Sensor network, and communicate to a main data logger through ANT wireless protocol. The ultimate goal of the system is to prevent the onset of hypothermia by unobtrusively monitoring physiological parameters of a subject and raising alarms if wrong patterns are detected.
Wearable Hybrid Sensor Array for Motor Cortex Monitoring
Authors: Shoureshi Rahmat A. , Aasted Christopher M.
Published: September 2012

As part of the goal of developing wearable sensor technologies, we have designed and built a hybrid sensor headset for monitoring brain activity. Through the use of electroencephalography (EEG) and near-infrared spectroscopy (NIRS), the sensor array is capable of monitoring neural activity across the primary motor cortex and wirelessly transmitting data to a computer for real-time processing to generate control signals, which are transmitted to wireless devices for various applications. This paper focuses on current results using this technology for artificial limb control and discusses the development of the headset as well as the neural networks employed for processing motor cortex activity and determining the user’s intentions. Initial results relevant to artificial limb control are presented and discussed, including the performance of the system when actuating an artificial limb with four degrees of freedom. Our headset provides a more natural control mechanism than traditional solutions, through the use of direct brain control. The technology resulting from this research is currently also being investigated for application in areas including phantom limb pain treatment, robotic arm control, general brain-computer interfaces, lie detection, and even a video game interface.
Wearable Inertia Sensor Application in the Rehabilitation Field
Authors: Tamura Toshiyo , Sekine Masaki , Miyoshi Hiroaki , Kuwae Yutaka , Fujimoto Toshiro
Published: September 2012

For the aged society, the physical activity of daily living is important to improve the quality of life. The simple quantitative evaluation of physical activity as well as rehabilitation is required We have developed wearable inertia sensors as well as evaluating system. We evaluated parameters such as RMS and autocorrelation function of stride and step for common neuro-physiological test in rehabilitation. The normal and fall-risk subjects were performed the 10 m trial. Furthermore obtained data from the wearable motion sensor were compared to the general estimation parameters such as performing time and Activities of Daily Living (ADL) score. In 10 meter trial, the result indicated that the ADL score is weakly correlated to the RMS of acceleration signal. However, the relationship between walking speed and RMS was highly correlated. The ADL score is general daily living activities and the walking is one of daily activities. The walking speed ,RMS and autocorrelation function of step and stride were significantly different between normal and fall-risk subjects. In conclusion, the obtained acceleration and angular velocity signals may help us the evaluation of daily activities and rehabilitation training quantitatively.
A Smart Biological Signal-Responsive Focal Drug Delivery System for Treatment of Refractory Epilepsy
Authors: Salam Muhammad Tariqus , Hamie Ali Hassan , Nguyen Dang Khoa , Sawan Mohamad
Published: September 2012

In this paper, we propose a new biological signal-responsive implantable device that triggers direct an anticonvulsive drug into the epileptogenic zone at electrographic seizure onset. We describe the high-performance seizure-onset detection algorithm, low-power circuit technique and focal drug delivery system. The implantable device is composed of a preamplifier, a signal processor, a seizure detector and a micropump. The device records high quality intracerebral electroencephalographic (icEEG) signals using high conductive electrodes and a low noise preamplifier. The recorded signal is processed continuously using low-power technique to detect onset of seizures accurately. The low-power miniaturized micropump is able to deliver sufficient amount of anticonvulsive drug in a short duration (50µL/sec) to epileptogenic zone. The detection algorithm was validated with Matlab tools and a prototype device was assembled with discrete components in a circular (Ø 40 mm) printed circuit board. The device was validated offline using the icEEG recordings obtained from 3 drug-resistant epilepsy patients. The average seizure detection delay was 10 sec from electrographic seizure onset, well before seizure progression to adjacent functional cortex.
BSN-Based Activity Classification: A Low Complexity Windowing-&-Classification Approach
Authors: Giuberti Matteo , Ferrari Gianluigi
Published: September 2012

Wireless sensor networks (WSNs) are becoming more and more attractive because of their flexibility. In particular, WSNs are being applied to a user body in order to monitor and detect some activities of daily living (ADL) performed by the user (e.g., for medical purposes). This class of WSNs are typically denoted as body sensor networks (BSNs). In this paper, we discuss BSN-based human activity classification. In particular, the goal of our approach is to detect a sequence of activities, chosen from a limited set of fixed known activities, by observing the outputs generated by accelerometers and gyroscopes at the sensors placed over the body. In general, our framework is based on low-complexity windowing-&-classification. First, we consider the case of disjoint (in the time domain) activities; then, we extend our approach to encompass a scenario with consecutive non-disjoint activities. While in the first case windowing is separate from classification, in the second case windowing and classification need to be carried out jointly. The obtained results show a significant detection accuracy of the proposed method, making it suitable for healthcare monitoring applications.
Development of Biocompatible Y-Stabilized ZrO2 Fabricated by Spark Plasma Sintering
Authors: Sakai H. , Asaoka Teruo
Published: September 2012

Due to the merits of zirconia ceramics such as high strength, toughness, abrasion resistance, and chemical stability in vivo, yttria-stabilized tetragonal zirconia polycrystals (Y-TZP) are currently used in the femoral head of hip prostheses. However, this material has a limited applications range because it is a bioinert material that does not interact with bone tissue and thus does not easily integrate directly in the bone. Therefore, we need to add different material’s layer which enables in vivo formation of bone-like apatite layer that exhibits bioactivity , composite compound bioactive ceramics, and facilitates interactions and integration in bone tissue. In addition, by developing a surface structure that enhances mechanical bonding, this material can be expected to be used as an alternative aggregate under load bearing conditions. In the present study, various method were carried out with the objective of controlling interactions between zirconia ceramics and the body such as structural design of the material surface, addition of bioactivity using reagents treatment, confirmation of formation of the apatite layer using immersion in simulated body fluid, wettability testing and develop structure with mechanical properties equal to bone strength.
Understanding In Vivo Abrasion Fatigue of Common Suture Materials Used in Arthroscopic and Open Shoulder Surgery
Authors: Hurren Christopher J. , Sutti Alessandria , Savage Earle , Slader Simon , Page Richard S.
Published: September 2012

In orthopaedic surgery the reattachment of tendon to bone requires suture materials that have stable and durable properties to allow healing at the tendon-bone interface. Failure rates of this type of surgery can be as high as 25%. While the tissue suture interface is a weak link, proportions of these failures are caused by in-vivo abrasion of the suture with bone and suture anchor materials. Abrasion of the suture material results from the movement of the suture through the eyelet by the surgeon during surgery, or with limb movement after surgery as the suture is not rigidly restrained within the eyelet. During movement the suture is subjected to bending and frictional forces that can lead to fatigue induced failure. This paper investigates the mechanism of bending abrasion fatigue induced failure of number two grade braided sheath only and braided sheath/multifilament core sutures. Sutures were oscillated over a stainless steel wire at low frequency under load in a dry state to simulate the bending and frictional forces between suture and eyelet. Failure mechanism was determined by video microscopy of the suture during abrasion combined with optical microscopy analysis of partially and fully abraded sutures. Braided only structures had high friction loading on the small number of fibres at the abrasion interface. This caused rapid single fibre breakages that accumulate to cause suture failure. The addition of ultra-high molecular weight polyethylene core fibres to a braided suture distributed the applied load across multiple fibres at the abrasion interface. This improved abrasion resistance by 15-20 times that of braided sheath alone.
Fabrication of Scaffold for Bone Regeneration by Taylor Made Stereolithography
Authors: Kumagai Kousei , Asaoka Teruo , Furukawa Katsuko , Ushida T.
Published: September 2012

Recently, regenerative medicine attracts very wide attention. Regenerative medicine is a method of medical care for the purpose of recovery of the lost human organic function, resulted by an accident or diseases. It is considered that there are three important factors in the regenerative medicine, cell, scaffold and cell growth factor. In this research, the talyor made stereolithography method was used to fabricate a highly precise biodegradable scaffold which is suited for individual bone defect part. The sterolithograph, one of rapid prototyping methods, is a method of modeling by using optical hardening resin irradiated by ultraviolet laser. We have used the optical hardening resin by mixing biodegradable β-tcp as the bone formation material. At present, confirmation of detailed fabrication conditions of stereolithography are in proceeding. Experiments by using osteoblasts cells are intended.
Optimal Position of A Long-Term Central Venous Catheter Tip in A Pediatric Patient with Congenital Diseases
Authors: Caruselli Marco , Galante Dario , Ficcadenti Anna , Carboni Laura , Franco Federica , Fabrizzi Benedetta , Amici Lucia , Giretti Roberto , Rocchi Giovanni , Rinaldelli Giampaolo
Published: September 2012

Progress in medical and scientific research has increased the chances of survival for young patients with congenital diseases, children who, in the past, would not have had any chance of survival. Nowadays, congenital diseases can be treated with appropriate replacement therapies. These treatments can be difficult to administer in young patients because of the high frequency of administration (sometimes more than a dose per week), the use of intravenous infusion and the long-term or life-term requirement.