This paper describes recent developments of moving materials operated by changes in temperature, hydrogen gas pressure and magnetic field. In order to obtain moving functions with high irradiation resistance for metallic glass, high transparency for high heat resistant glassy ceramics and extremely large motion for lightweight polymer, unimorph structural device driven by glass transition have been developed. To get high responsiveness operated by magnetic field, new movable devices of unimorph magnetostrictive alloy films were developed. High susceptibility with high resistance to noise was also found for the giant magnetostrictive Fe-Pd stainless alloy. To obtain high power, a movable unimorph devise of hydrogen storage LaNi₅ film deposited on substrate was developed. In order to get large motion, unimorph structural composite sheets constructed by the silicon polymer with and without hydrogen storage LaNi₅ fine powder dispersion.

Al₂O₃ reinforced by SiC whiskers (Al₂O₃/SiC-W) was sintered in order to investigate the fatigue strength of crack-healed specimens at high temperature. A semi-elliptical surface crack of 100μm in surface length was introduced on each specimen surface. These specimens were crack-healed at 1300°C for 1 h in air, and static and cyclic fatigue strengths were systematically investigated at room temperature, 900°C, and 1100°C by three-point bending. The static and cyclic fatigue limits of the crack-healed specimens were more than 70% of the average bending strength at each testing temperature. Crack-healed specimens of Al₂O₃/SiC-W were not sensitive to static and cyclic fatigues at room temperature and high temperatures. Therefore, the combination of crack-healing and whisker reinforcement can play an important role in increasing static and cyclic fatigue strengths at high temperature.

One unique property of a Machine Augmented Composite (MAC) is its ability to convert a compressive force into a shear force, and vice versa, simply by the geometry of its angled sidewalls. We have discovered that a non-spinning ball dropped at a normal angle onto the MAC’s surface rebounds from that surface at an angle different from the normal and develops a significant rotational velocity. The MAC can be designed so that the spin imparted on the ball is either clockwise or counterclockwise and tailored so that the ball’s oblique angle rebound is either positive or negative from its normal angle. Through finite-element analyses and experiments, the magnitude and direction of the spin can be precisely controlled by tailoring the stiffness of the MAC through the properties and dimensions of its constituent materials.

Delamination is a significant defect of laminated composites. The present study employs an electrical resistance change method in an attempt to identify internal delaminations experimentally. The method adopts reinforcing carbon fibers as sensors. In our previous paper, an actual delamination crack in a Carbon Fiber Reinforced Plastics (CFRP) laminate was experimentally identified with artificial neural networks (ANN) or response surfaces created from a large number of experiments. The experimental results were used for learning of the ANN or regression of the response surfaces. For the actual application of the method, it is indispensable to reduce the number of experiments to suppress the total experimental cost. In the present study, therefore, FEM analyses are employed to make sets of data for learning of the ANN. First, electrical conductivity of the CFRP laminate is identified by means of the least estimation error method. After that, the results of FEM analyses are used for learning of the ANN. The method is applied to actual delamination monitoring of CFRP beams. As a result, the method successfully monitored the delamination location and size only with ten experiments.

Si₃N₄/SiC composite ceramics were hot-pressed to investigate the crack-healing behavior under stress. Semi-elliptical surface cracks of 0.1 mm in surface length were made on each specimen. The pre-cracked specimens were crack-healed under cyclic or constant bending stress, and the resultant bending strength and cyclic fatigue strength were studied. The threshold stress for crack-healing was investigated at healing temperatures of 1000° and 1200°C. The cyclic fatigue strengths of crack-healed specimens were also investigated at healing temperatures of 900° and 1000°C. The main conclusions are as follows: (1) The threshold cyclic and constant stresses for crack-healing, below which pre-cracked specimens recovered their bending strength, were 300 MPa which was 75% of the bending strength of the pre-cracked specimens, and (2) The crack-healed specimens exhibited quite high cyclic fatigue strength at crack-healing temperatures of 900° and 1000°C.

Controlling the interaction of surfaces with macromolecules, such as proteins and antibodies, is the key to producing biocompatible prosthetic devices, biosensors and diagnostic arrays. The development of technologies to control these interactions will result in the early detection of disease and have the potential to dramatically reduce costs associated with clinical treatment. For example, tethering functional anti-bodies to a surface in a patterned array allows the selection of specific proteins from a microlitre serum sample, immediately identifying diseases, well before the symptoms are manifested. Unfortunately, simple physical absorption of proteins onto most surfaces results in changes in their structure and loss of function. The use of ions from plasmas allows flexibility in surface modification by accessing a variety of ion energies and activated chemical species. In this paper we describe plasma based techniques which are being developed to modify the chemistry and morphology of surfaces in order to optimise their interaction with biomolecules. Early results of plasma processes to activate surfaces for non specific attachment of proteins by hydrophilic /hydrophobic interactions are presented, with particular attention to the time stability of such treatments, which is of special interest.

Structural health monitoring (SHM) is currently using piezoelectric wafer active sensors (PWAS) permanently attached to the structure with adhesives. This is often a burdensome and time-consuming task, especially for large structures such as aircraft, bridges, etc. In addition, there are critical applications where the rigid piezoceramic wafers cannot conform to curved surfaces. Another important issue is the long term durability of the bonded interface between the PWAS and the structure, which is often the durability weak link. An in-situ fabricated smart sensor may offer better durability. This paper considers the possibility of fabricating the PWAS directly to the substrate structure in order to alleviate these problems. The paper starts with a review of the state of the art in active composite fabrication. Then, two concepts are considered: the piezomagnetic composite sensor and the piezoelectric composite PWAS. The piezomagnetic composite was fabricated using Terfenol-D magnetostrictive powder in a fiber reinforced composite beam. The strain-induced magnetic field was detected with a Lakeshore gaussmeter. The piezoelectric composite sensor was prepared by mixing lead zirconate titanate (PZT) particles in an epoxy resin. The mixture was applied onto the structural surface using a mask. After curing, the piezo composite was sanded down to the desired thickness and poled under a high electric field. The resulting in-situ composite PWAS was utilized as a sensor for dynamic vibration and impact. Characterization of the in-situ composite PWAS on aluminum structure have been recorded and compared with ceramic PWAS before and after poling. To evaluate the performance of the in-situ composite PWAS, both vibration and impact tests were conducted. Both experiments indicated that in-situ fabrication of active materials composites poses itself as a good candidate for reliable low-cost option for SHM smart sensor fabrication.

The study investigating the electrical properties of dense lead-free piezoelectric ceramics in the (1-x)Sr₂NaNb₅O₁₅-xCa2NaNb5O15 (SCNN) system with x ranging from 0.05 to 0.35 is reported here. Materials were produced with Spark Plasma Sintering (SPS) method. X-Ray diffraction patterns all showed a single tetragonal tungsten bronze phase, peak broadening being seen on increasing the Ca content. The lattice constant calculation indicated distortion and shrinkage of the crystal structure with Ca substitution. Ferroelectric and piezoelectric properties of SCNN greatly depended on the Ca content. The composition with x =0.15 exhibited the greatest polarization with Pr =3.0 μC cm^-2and piezoelectric constant of d₃₃ =96 pC/ N, whereas the compositions with x =0.30 and 0.35 almost lost their ferroelectricity and piezoelectricity. Not only investigation of materials properties but also application possibility as a sensor is surveyed. The ultrasonic waves generated by SCNN material as a sensor are much clearer that that by commercially available PZT materials. This study apparently indicates that lead-free SCNN piezoelectric ceramics have potential for electromechanical application.

Pb(Zr_xTi_1-x)O₃ (PZT) thin films were in situ-grown on Pt/Ti/SiO₂/Si substrates by a hybrid process consisting of the sol-gel method and pulsed-laser deposition (PLD). The deposition temperature to obtain the perovskite phase in the hybrid process is 460°C, and is significantly lower than that in the case of direct film deposition by PLD on a Pt/Ti/SiO₂/Si substrate. X-ray diffraction analysis indicated that the preferred orientation of PZT films can be controlled using the layer deposited by the sol-gel method and highly (111)- or (100)-oriented PZT films were obtained. A transmission electron microscopy (TEM) image showed that the film had a polycrystalline columnar microstructure extending through its thickness, and no sharp boundary was observed between the layers deposited by the sol-gel method and PLD. A high-resolution electron microscopy image and electron diffraction analysis revealed that the crystalline lattice of the layers deposited by the sol-gel method and PLD was continuous and there was no difference in crystalline orientation between the layers. These results indicate that the solid-phase epitaxial effect between the PZT layers deposited by the sol-gel method and PLD decreases the deposition temperature to obtain the perovskite phase during PLD, and causes the films to exhibit the same preferred orientation as that of the layer deposited by the sol-gel method. The dielectric constant and remanent polarization of the films in situ deposited at 460°C were approximately 900 and 15 μC/cm², respectively.

Piezoelectric shunt damping is a method to reduce structural vibration by shunting a piezoelectric element with an electrical circuit. This paper proposes a method to identify the physical parameters that are required to design piezoelectric shunt damping systems. Employing self-sensing actuator methodology, the proposed method requires no additional sensor or actuator other than a simple bridge circuit. The parameters can be identified from a transfer function simply by linear least squares method. To demonstrate the validity of the proposed method, the shunt damping of the steel plate with the piezoelectric ceramic is performed based on the identified parameters.

Low dimensional systems such as nanotubes and nanowires have fascinating, and technologically useful, optical and electrical properties. Studies on these systems advance our knowledge on the science at the nanoscale, while simultaneously provides the possibility for developing miniaturized electronics and optoelectronics. The material system attracting increasing attention is zinc oxide (ZnO),^1-6which is a II-VIcompound semiconductor with a wide and direct banc gap of 3.37 eV at room temperature. ZnO has demonstrated unique properties and potential applications in manifold fields, such as transparent electronics, ultraviolet (UV) light emitter, surface acoustic wave devices, gas sensors and magnetoelectronics. It is shown to have wurtzite structure with lattice constant a = 3.249 Α, c = 5.207 Α. Its large exciton binding energy (60 meV), which is much greater than the thermal energy at room temperature, makes it a promising candidate for applications in blue-UV light emission and room temperature UV lasing⁷. Furthermore, its high piezoelectric constant (d₃₃=246) makes it a highly valuable material for fabricating mechanical devices, such as acoustic transducers, sensors and actuators.

This paper addresses the use of RF MEMS devices in wireless and satellite communication systems. It describes the MEMS actuators typically needed for such devices. Novel configurations are presented for MEMS variable capacitors, MEMS tunable inductors and RF MEMS mutiport switches. The tuning range of the variable capacitor was measured and found to be 280%, which far exceeds that of the traditional parallel plate MEMS variable capacitors. The MEMS tunable inductor is realized using MEMS fixed inductors, capacitors and a variable MEMS capacitor. The proposed MEMS multiport switch has demonstrated a superior RF performance up to 20 GHz.

In this paper, we present an application devoted to measure the dynamic response of a prototype of a support of a star tracker. Four different techniques have been used and compared with each other. Specifically Electronic Speckle Pattern Interferometry and Speckle Shearography have been used as full field modal appropriation techniques, impact hammer and accelerometer as a broad band conventional technique and finally broad band with impact hammer and FBG sensor as a newly proposed methodology. Modal parameters have been retrieved using all the four methodologies described above and compared. We have demonstrated that FBG sensors can be used to retrieve modal parameters useful as indicators of the state of health of a structural component. When embedded the FBG can be used actively also during the qualification process of the smart component as well as in service for shape monitoring. This latter purpose is important for precision pointing instruments such as the star tracker under investigation.

We have studied the carrier transport properties of amorphous organic material tris (8-hydroxyquinoline) aluminum (Alq₃) for Al, LiF/Al, NaCl/Al, KBr/Al cathodes and ITO and ITO/HTL anodes at room temperature. The investigation was made by the current - voltage, luminescence - current characteristic measurements. The current density increases by several orders for LiF/Al and NaCl/Al cathodes over that of Al at a given bias voltage. The electron injection processes at the metal/organic contact dominate the current - voltage characteristics. The carrier injection seems to be limited by the charge hopping of interfacial molecular sites. We have also developed a process method for the preparation of anodic indium-tin-oxide (ITO) surface for high efficient organic light emitting diodes (OLEDs). X-ray photoelectron spectroscopy (XPS) was used to measure atomic concentration of each element In, Sn, O and C on treated ITO surface. Scanning electron microscopy and atomic force microscopy were used to scan the surface profiles of ITO. The OLED performance considerably improved by the ITO surface treatments as well as by ITO/HTL anode due to the reduction of holes injection barrier between ITO and Alq₃ interface.

An artificial muscle is an ionic polymer-metal composite (IPMC) which is made out of a high polymer gel film whose surface is plated with gold. Our goal is to realize bio-inspired soft robots, for example, a snake-like swimming robot or multi-degree-of-freedom (DOF) micro-robot manipulator. To realize a snake-like or a multi-DOF bending motion, we cut electrodes on the surface of the actuator in order to control each segment individually. We have developed a variety of motions from this patterned actuator including a snake-like motion. We have also proposed kinematic modeling of the manipulator which simply describes various multi-DOF motions of the artificial muscle. This model is applied to visual feedback control of the manipulator system using a Jacobian control method. For the feedback control, we have developed a visual sensing system using a 1ms high-speed vision system which has a fast enough response to capture the fast actuator motion. We have also made the device swim freely forward and backward by finding the optimal voltage, phase and frequency. In this report, we show some results from simulations of the proposed manipulator control method and experimental results from visual sensing of the bending motion and snake-like swimming of the actuator.

This paper presents synthesis and characterization of polypyrrole based conducting polymers in terms of electronic and mechanical disciplines. Using the electrochemical polymerization approach, conducting polymer samples with different dimensions (length, width, and thickness) was fabricated. For each sample, both sinusoidal and step excitations were used to study its mechanical and electrical properties. An equivalent electric circuit based on constant phase element (CPE) is proposed to model such responses. Electrochemical impedance spectroscopy (EIS) method was used to identify the relationship between the dimensions of conducting polymers and model elements parameters.

The synthesis of acrylamide based hydrogels incorporating a small proportion of hydrophobic functional groups results in a hydrogel structure with improved mechanical properties. In particular increased mechanical toughness and tensile strength whilst maintaining a relatively high swelling ratio. A method of increasing toughness has been developed by introducing a number of long alkyl chain hydrophobic groups into the hydrophilic structure. These hydrophobic groups create domains of densely clustered polymer chains within the highly swollen hydrogel matrix. Single edged notch tensile tests demonstrate a significant increase in fracture energy when the hydrophobes are able to interact in aqueous solutions compared to gels swollen in organic solvents in which the hydrophobes act independently. Therefore it is speculated that these domains increase energy dissipation around the crack tip during fracture causing an increase in mechanical toughness.

Conducting polymer actuators with favourable properties such as linearity, high power density and compliance are of increasing demand in micro applications. These materials generate forces over two times larger than produced by mammalian skeletal muscles. They operate to convert electro chemical energy to mechanical stress and strain. On the other hand, the application of conducting polymers is limited by the lack of a full description of the relation between four essential parameters: stress, strain, voltage and current. In this paper, polypyrrole helix tube micro actuator mechanical characteristics are investigated. The electrolyte is propylene carbonate and the dopant is TBA. PF₆. The experiments are both in isotonic and isometric conditions and the input parameters are both electrical and mechanical. A dual mode force and length control and potentiostat / galvanostat are utilized for this purpose. Ultimately, the viscoelastic behaviour of the actuator is presented in this paper by a standard stress relaxation test. The effect of electrical stimulus on mechanical parameters is also explored by cyclic voltametry at different scan rates to obtain the best understanding of the actuation mechanism. The results demonstrate that the linear viscoelastic model, which performed well on conducting polymer film actuators, has to be modified to explain the mechanical behaviour of PPy helix tube fibre micro actuators. Secondly, the changes in mechanical properties of PPy need to be considered when modelling electromechanical behaviour.

An approximate relationship between strain and applied potential was derived for composite actuators consisting of single-wall carbon nanotubes (SWNTs) and conductive polymers (CPs). During deriving the relationships, an electrochemical ionic approach is utilized to formulate the electromechanical actuation of the composite film actuator. This relationship can give us a direct understanding of the actuation of a nanoactuator. The results show that the well-aligned SWNTs composite actuator can give good actuation responses and high actuating forces available. The actuation is found to be affected by both the SWNTs and CPs components and the actuation of SWNTs component has two kinds of influences on that of the CPs component: reinforcement at the positive voltage and abatement at the negative voltage. Optimizations of SWNTs-CPs composite actuator may be achieved by using well-aligned method as well as choosing suitable electrolyte and input voltage range.

In this study, the effects of surface treatments were investigated on the mechanical response of the LaNi₅ thin film actuator deposited on polyimide substrates. Since controlling the hydrogen concentration in film by reversible pressure change drives this actuator, this film actuator can be expected as a sensor and/or a controller of hydrogen gas flux in various hydrogen-related devices. This significantly improved mechanical response was attributed to the switching of the reactions in the rate determining steps.

Wireless capsule endoscopy (WCE) is a new technology to evaluate the patient with obscure gastrointestinal bleeding. However, there is still some deficiency existing in the current WCE, for example, lack of ability to biopsy and precisely locate the pathology. This study aimed to prepare and characterize TiNiCu shape memory alloy thin films for developing microgripper for biopsy (tissue sampling and tagging) applications. Ti₅0Ni₄1Cu₉ thin films were prepared by co-sputtering of TiNi and Cu targets, and their transformation temperatures were slightly above that of human body. Results from differential scanning calorimetry, in-situ X-ray diffraction, curvature and electrical resistance measurement revealed clearly martensitic transformation of the deposited TiNiCu films upon heating and cooling. The biocompatibility of the TiNiCu films in the simulated gastric and intestinal solutions was also studied. Results showed the release of Ni and Cu ions is much less than the toxic level and the film did not lose shape memory effect even after 10-day immersion in the simulated solutions. TiNiCu/Si micro-cantilevers with and without electrodes were fabricated using the conventional micromachining methods and apparent shape memory effect upon heating and cooling was demonstrated.

The application of Shape Memory Alloys (SMA) in mechanical engineering (ME) or in civil engineering (CE) requires the tuning of the physical properties with each particular need. When the target involves dampers for quakes in CE the number of full working cycles is relatively small (i.e. 200) but the application requires guaranteed behavior after several years of inactivity. On the contrary some devices in ME may need relatively high frequencies operating for a long period of time. In this work the mesoscopic effects in the SMA are quantified to ensure guaranteed behavior in the frame of dampers for CE applications. For instance, the actions of accumulated deformation in cycling and the changes induced by external temperature (i.e., summer-winter) are evaluated. Also, the perturbations induced by diffusive (induced by phase metastability, i.e. produced by microscopic interactions) are considered. In particular, the phase coexistence effects are visualized in Cu-based and partially in NiTi alloys. The practical creep induced by cycling and the coexistence actions are decisive in damping applications.

Phase transformations and crystal structures of nitinol shape memory alloy are investigated by varying with heat treatment conditions through DSC (differential scanning calorimetry) and XRD (X-ray diffraction). Heat treatment conditions are considered as heat treated times of 5min, 15min, 30min, and 45min as well as heat treated temperatures of 400°C, 500°C, 525°C, 550°C, 575°C, 600°C, 700°C, 800°C, and 900°C. In addition, tensile tests are conducted to investigate thermomechanical behaviors of nitinol shape memory alloy through material testing system by varying with heat treated temperatures and environmental temperatures. According to these results, heat treatment conditions are found to be significantly affected on phase transformations, crystal structures, and thermomechanical behaviors of nitinol shape memory alloy.

Several nickel-titanium alloys have been mechanically tested over a range of temperature, such that superelastic deformation should or should not take place. Both conventional uniform loading (tension and compression) and nanoindentation (using a range of conditions) have been carried out. Indentation tests were conducted using either spherical or Berkovich tips, with either high or low load configurations. These experiments were conducted at various temperatures, corresponding to above Af, below M_f, or at an intermediate temperature. Elastic constants, superelasticity parameters and plastic deformation characteristics obtained using conventional mechanical tests are compared with indentation responses and conclusions drawn about how best to identify superelastic deformation via nanoindentation data. In particular, it is concluded that use of spherical indenters facilitates such identification. Scale effects are also discussed. These experimental investigations are supplemented by preliminary development of an ABAQUS finite element model suitable for study of the indentation response of superelastic material.

Fine needle-like crystals of C₆₀, “C₆₀ nanowhiskers”, were found in 2001 in a colloidal solution of PZT ceramics with added C₆₀. Not only the C₆₀ nanowhiskers but also nanowhiskers composed of C₇₀ and C₆₀ derivatives can be synthesized at room temperature by using the liquid-liquid interfacial precipitation method (LLIP method). Tubular nanowhiskers composed of C₆₀ and C₇₀ molecules have been successfully fabricated by using the LLIP method as well. The tubular fullerene nanowhiskers are named “fullerene nanotubes” here. The tubular fullerene nanowhisker is a new form of single crystalline needle-like crystal whose wall is composed of fullerene molecules. In this paper, structural, electrical and mechanical properties of the fullerene nanowhiskers and fullerene nanotubes are discussed.

C₆₀ nanowhiskers fabricated by the liquid-liquid interfacial precipitation method were sintered at 800 °C under 5.5 GPa for 2 h. Structural, mechanical, and electrical properties of sintered C₆₀ nanowhiskers were compared with those of sintered pristine C₆₀ powder under the same conditions. Sintered C₆₀ nanowhiskers showed a relatively high density and a fine texture as compared to sintered pristine C₆₀ powder probably due to the fibrous morphology of starting C₆₀ nanowhiskers. Analysis using four-probe micro manipulator system (SUNYOU, MMS0024-01) revealed low electrical resistivity for the sintered samples. Electrical resistivity of sintered C₆₀ nanowhisker was slightly higher than that of sintered pristine C₆₀ powder. Both of the sintered samples showed high micro-Vickers hardness about 1100 HV. XRD patterns of the sintered samples showed only diffuse peaks that are characteristic of glassy carbon. The peak intensity of glassy carbon in the sintered C₆₀ nanowhiskers was weaker than that of sintered pristine C₆₀ powder, which was consistent with the different electrical resistivity. Characterization by FTIR and Raman spectroscopy confirmed no sign of C₆₀ molecules for both the sintered samples indicating that C₆₀ molecules were significantly reduced by the high temperature and high pressure treatment. The differences of textural and electrical properties between sintered C₆₀ nanowhiskers and sintered pristine C₆₀ powder suggest a good sinterability of the C₆₀ nanowhiskers due to their fibrous morphology as compared with pristine C₆₀ powder.

Gallium nitride (GaN) thin films were grown by laser induced molecular beam epitaxy (LIMBE). Their microstructures were studied by transmission electron microscopy (TEM). Threading dislocations with Burgers vectors of 1/3<1120>, 1/3<1123> and [0001] were observed as common linear defects with predominantly the first type. Additionally, nano-structured planar defects as called domain boundaries were found. Convergent beam electron diffraction (CBED) technique coupled with chemical and cathodoluminescence measurements was employed to characterize the nano-structured domains, indicating that a domain is of Ga-polarity with respect to the adjacent matrix which is of N-polarity. It was found that experimental parameters such as N/Ga ratio were closely associated with the development of domains as well as the surface morphology. High-resolution transmission electron microscopy (HRTEM) results indicate that IDBs have Ga-N bonds between domains and the adjacent matrix without displacements along the c-axis in the basal planes. Upon the determination of the polar property of a thin GaN film and the optimization of experimental conditions, the nano-structured GaN films can be modified and controlled by changing substrate and pre-growing an AlGaN layer and a GaN buffer layer.

A dewetting process of an evaporating solution is used to form micrometer-sized amorphous droplets, or domes, of the low molar mass solute on substrates such as silicon, mica, glass, and indium-tin-oxide. Using dewetting, the organic hole transporting material of organic light emitting diodes was patterened into micrometer-sized domes on an indium-tin-oxide electrode. Annealing led to a structural change of the domes, which was investigated by optical and electron microscopies. The dewetted dome samples were then coated with electron transport material and top electrode to give functioning organic light emitting diodes. Microscope imaging reveals a strong luminescence from the micrometer-sized domes.

Nanostructural vanadium dioxide thin films are investigated as intelligent window coatings. The films are fabricated using reactive sputtering and post annealing. A reversible semiconductor to metal phase transition for as-deposited VO₂ nanostructure films with grain size of ~8nm takes place at a temperature of 35°C, which lowers about 33°C in comparison with a phase transition temperature of 68°C in conventional VO₂ films with a grain size of 1-2 μm. The results indicate that the nanostructural VO2 films are more suitable to the application for smart thermochromic glazing of windows than that of conventional VO₂ films.

EBG structures are typically two or three dimensional periodic media characterized by the capability to inhibit the electromagnetic wave propagation for each angle and each polarization in a specific frequency band. These complex structures present different degrees of freedom, that can be used to optimize the performances of the application. On the other hand, the management of different degrees of freedom can result in the increasing of the complexity in the entire device-design procedure. The aim of this research is to analyse the optimization of EBG materials by means of a new technique: the Genetical Swarm Optimization (GSO). This approach consists of a co-operation of GA and PSO. The GSO results in a fast method for optimization of complex nonlinear objective functions and its wider potential makes it suitable for every electromagnetic applications. These optimized synthetic materials can represent an opportunity for the development and design of innovative electromagnetic devices.

Al₂O₃ reinforced by SiC whiskers (Al₂O₃/SiC-W) was hot pressed to investigate the crack-healing behavior. Semi-elliptical surface cracks of 50 to 450μm in surface length were introduced using a Vickers indenter. The specimens containing pre-cracks were crack-healed at temperatures between 1000°C and 1300°C for 1h in air, and their strengths were measured by three-point bending tests at room temperature and elevated temperatures between 400°C and 1300°C. The results show that Al₂O₃/SiC-W possesses considerable crack-healing ability. The surface cracks with length of 2c=100μm could be healed by crack-healing at 1200°C or 1300°C for 1h in air. The maximum crack size that can be healed for Al₂O₃/SiC-W is 2c=200μm. Fracture toughness of the material was also determined. As expected, the SiC whiskers made their Al₂O₃ tougher.

The goal of this research is to design and evaluate a mutlilayer bender actuator, on a concept that each ceramic layer has different value of piezoelectric d₃₁ coefficient. By stacking the ceramic layers with the different piezoelectric d₃₁ coefficient, the internal stress within the actuator body became maximized. Three type actuators (called as sample 1, 2 and 3) were presented in a specification of stacking ceramic layers with low and high piezoelectric properties. Sample 1 was actuator with high piezoelectricity (d₃₁ = -210pC/N), Sample 2 with low and high piezoelectricities (d₃₁=-100 and -210 pC/N) ), and Sample 3 with low piezoelectricity (d₃₁=-100 pC/N). Sample 2 exhibited higher displacement than the other samples under application of a voltage over 50 V, due to higher internal stress between the top and bottom layers. In addition, high generative force can be expected at the multilayer structure actuator, sample 2, with the two piezoelectric components over actuator with one component.

This paper discusses the growth of silicon nanostructures on silicon (100), (110) and (111) substrates by electron beam annealing. The nanofabrication procedure involves annealing of the untreated Si substrates in the temperature range 750°C - 1200°C using a raster scanned 20 keV electron beam. Nanostructuring occurs as a result of kinetic amplification of the surface disorder induced by thermal decomposition of the native oxide. Pyramidal and truncated pyramidal nanocrystals were observed on Si(100) surfaces. The nanostructures are randomly distributed over the entire surface and square-based, reflecting the two-fold symmetry of the substrate surface. Similar square-based pyramidal structures with four equivalent facets are observed following nanostructuring of Si(110). With Si(111), nanostructure growth occurs preferentially along step-edges formed on the vicinal surfaces. Significant differences in nanostructure shapes formed on step-edges and terraces are related to the different growth mechanisms on the unreconstructed and 7x7 reconstructed domains respectively.

This paper presents theoretical and experimental investigation of mechanical-electrical properties of conducting polymers based bimorph sensors. A material parameter, h_CP, is proposed to represent linear relationship between induction charge and the applied external deformation. Based on this assumption, a constitutive equation for bimorph sensors under steady-state external loadings are constructed and then solved. Mechanical-electrical properties of bimorph sensors are experimentally studied using both vibration-amplitude sweep mode and frequency sweep mode. The material parameter h_CP, is identified by comparing theoretical analysis and experimental results. The applications of conducting polymers based bimorph sensors in smart structures are also discussed.

Nanoparticles of CeO₂ doped with 10 mol% Dy₂O₃ have been synthesized via a homogeneous precipitation method, employing nitrates as the starting salts and hexamethylenetetramine (HMT) as the precipitant, which was achieved under ambient pressure and hydrothermal conditions, respectively. Characterizations of the powders were made by elemental analysis, differential thermal analysis/thermogravimetry (DTA/TG), X-ray diffractometry (XRD) and field-emission scanning electron microscopy (FESEM). The results show that an additional hydrothermal treatment affects significantly the powder properties, and well dispersed, nanocrystalline solid solution with expected dopant content was obtained under the reaction conditions.

To protect space structures from debris impact, the new types of shield using a self-sealing materials are suggested. A hole by debris impact on shield will be fixed with the self-sealing materials by melting, sealing and solidification. Time to seal impact hole was experimentally simulated. If time to seal impact hole was assumed to be about 5 s, viscosity of self-sealing materials should be about 0.5 Pa s. In addition, glasses with supercooled liquids at elevated temperatures were also suggested as candidate materials for sealing, because low values of viscosity were obtained below melting points. From these results, boride ceramics, high temperature polymer materials including a liquid-crystal and light metallic glasses were suggested as the candidate materials for the self-sealing system.

Inspired by the water-repellent behavior of the micro- and nano-structured plant surfaces, superhydrophobic materials, with a water contact larger than 150 degree, have received a lot of research attentions recently. It has been suggested that contamination, oxidation and current conduction can be inhibited on such superhydrophobic surfaces, and the flow resistance in the microfluidic channels can also be reduced using super water-repellent materials. In order to prepare superhydrophobic materials, we have developed two simple approaches for fabricating tunable superhydrophobic surfaces using nanosphere lithography and plasma etching. In the first case, the polystyrene nanospheres were employed to create well-ordered rough surfaces covered by gold and alkylthiols. Using oxygen plasma treatment, the topmost surface area can be modified systematically, as the result the water contact angle on such surfaces can be tuned from 132 to 170 degree. The water contact angles measured on these surfaces can be modeled by the Cassie’s formulation without any adjustable parameter. In the second approach, thin films of Teflon were spin-coated on the substrate surfaces and treated by oxygen plasma. Superhydrophobic surfaces with water contact angle up to 170 degree were obtained by this approach. If the ITO glasses were used as the substrates, the hydrophobicity of the surface can be tuned by applying DC voltage. Water contact angle can be adjusted from 158 degree to 38 degree.

In order to evaluate influence of electron beam (EB) irradiation on elasticity and stress- strain curve of composite materials reinforced by carbon fiber (CF), carbon fiber reinforced polymer (CFRP) and carbon fiber reinforced graphite (C/C) were treated by EB irradiation of 0.3 MGy. Since the EB strengthening was mainly dominated by the ductility enhancements of carbon fiber and matrix of epoxy resin, EB irradiation enlarged fracture stress and enhanced fracture strain of CFRP. Furthermore, EB irradiation slightly enhanced bending elasticity of CFRP and largely enhanced the initial spring constant related to elasticity of C/C coil. Although the elasticity enhancement of carbon fibers did not largely contribute that of CFRP, that of treated graphite matrix in C/C mainly caused the C/C coil elasticity enhancement by EB irradiation. Such a new treatment is a dream-worthy technology for structural materials to be applied in the fields of future engineering.

An effect of electron beam irradiation on intelligent properties including mist resistance, wetting and hardness were studied for polymers. The electron beam irradiation decreased the time to clear vision on the misted polymers samples. The treatment was conformed to show the mist resistance of the polymer. To discuss the effect of electron beam on mist resistance, the water wetting indicated by the surface energy was evaluated by using contact angle of sessile drop. Based on ESR results, the effects of electron beam on the mist resistance were discussed. Electron beam irradiation broke the weakly bonded pairs in polymer and formed the dangling bonds. In addition, EB-irradiation enhanced Vickers’ hardness for polycarbonate.

To develop an optical scanning device, the magnetostrictive alloy thin films were prepared on silicon wafer and polyimide substrate by d.c. magnetoron sputtering process. The TbFe1.8 film shows a giant positive magnetostriction of about 1200 ppm at 5 kOe, whereas the SmFe2.5 shows a giant negative magnetostriction of about 1200 ppm. The magnetostrictive alloy thin films device showed reproducibility below 5 kOe of magnetic field.

A novel mesoporous material Ti-MSU has successfully synthesized by hydrothermal treatment using nanoseed-TS-1 as precursors. The sample was characterized by different techniques such as: IR, XRD, BET, UV-Vis. The obtained results revealed that the product was highly ordered mesostructure with pore size of 24 A^o and the wall of crystalline nature. Ti-MSU was tested in the photocatalytic oxidation of chlorophenol. Ti-MSU sample showed much higher activity compared to that of TS-1 and P25 in the photocatalytic oxidation of orthochlorophenol.

Fe-SBA-15 was successfully synthesized by hydrothermal treatment in one step . Different techniques such as XRD, BET, HRTEM, UV-vis have been used to characterize the Fe-SBA-15 samples. Obtained results have shown that the obtained Fe-SBA-15 samples have highly ordered hexagonal mesostructure with large pore size of about 64Å. Most Fe species in the Fe-SBA-15 were tetrahedrally coordinated. The sample exhibited high stability by calcination at high temperature to remove the template. The Fe-SBA-15 catalysts were tested in catalytic oxidation of phenol and photocatalytic oxidation of chlorophenol. The results indicated that Fe-SBA-15 exhibited the high catalytic activity in these reactions.

Wireless communications systems require new materials with special properties in specific frequency bands. The investigations on ZST type ceramics, (Zr_0.8Sn_0.2)TiO₄, presented in this paper, recommend this materials for applications in microwaves and millimeter waves. The ZST materials were prepared using a standard solid-state reaction technology. The samples morphology, phase-composition and microstructure investigations were performed by using the scanning electron microscopy (SEM), and energy-disperse X-ray spectrometry (EDX). The crystalline phases were identified by X-ray diffractometry (XRD). The electromagnetic properties were investigated on ZST resonators by using a Computer Aided Measurement (CAM) in microwaves, combining a HP 8757C network analyzer and a HP 8350B sweep oscillator. The dielectric characteristics at millimeter waves were analyzed by investigation of the Whispering Gallery Modes on ZST disks. The low level NiO doping provides ZST materials with temperature coefficient τ_f in the range (-2 ÷ +4) ppm/°C and decreases the dielectric loss. Materials with high values of the Qf product up to 50,000 and a dielectric constant about 36 at microwave frequencies were obtained. ZST dielectric resonators and substrates for hybrid integrated circuits with dimensions 1” x 1” and thickness in the range 0.6 ÷ 1 mm were manufactured.

We synthesized polythiophene (PTh) derivatives having a methyl group at 4-position and a mesogenic group, or an ionic group at 3-position in the thiophene ring via a flexible spacer by oxidative polymerization with FeCl₃ and investigated regioregularity, thermal, electrical and optical properties of the PTh derivatives. The regioregularity of the PTh derivatives with a mesogenic group was over 90%. A smectic phase was observed for two PTh derivatives with mesogenic group. The electrical conductivity was about 10^-3~10^-4 Scm^-1for the PTh derivatives doped with I₂ vapor in the film state. PTh derivatives containing methylimidazolium salt derivative at the 3-position of thiophene ring were soluble in water. To investigate ionochromism of the aqueous solution of PTh derivatives containing methylimidazolium salt derivative, some salts were added to the aqueous solution. The absorption peak based upon the π conjugation of the polymer backbone was shifted to the longer wavelength region, when NaI, KI or LiI salts were added to the aqueous solution of the PTh derivatives. This ionochromism behavior of the aqueous solution of PTh derivatives containing methylimidazolium salt derivative would be applied to the chemosensor.

Smart fabrics are those with electronic devices embedded in the material structure. Metallic fibres are not compatible with a comfortable fabric and flexible fibres with electronic capabilities are desired. Polyaniline (PANi) and carbon nanotubes (CNTs) show potential for application in different electronic devices such as conductive yarn, sensor, actuator, battery, capacitor and diode. The development of fibres from these materials can be considered as potentially useful for the manufacturing of smart fabric which embedded non metallic electronic devices. This paper describes the influence of CNT addition on the electronic, mechanical of PANi-CNT composite fibre which was fabricated by a wet spinning process. PANi(EB)-nanotube (SWNT, DWNT)- dimethyl propylene urea (DMPU) composite spinning solution have been prepared by an ex-situ process. The size distribution of nanotubes has been characterized by zeta sizer. Furthermore the rheological study has been conducted for optimization of PANi/CNT weight ratio to produce solutions with suitable fluidity for spinning process. In spite of the great impact of nanotubes on the mechanical and electrical properties of PANi composite fibre, the structure of the composite is far from ideal and it can be proposed that by proper ex-situ and in-situ solution preparation and processing techniques further improvements in properties are possible.

A cold hibernated elastic memory (CHEM) foam structure is one of the most recent results of the quest for simple, reliable and low-cost expandable space structures. The CHEM technology utilizes shape memory polymers in open cellular (foam) structure or sandwich structures made of shape memory polymer foam cores and polymeric composite skins. It takes advantage of the polymer’s heat activated shape memory in addition to the foam’s elastic recovery to deploy a compacted structure. The glass transition temperature Tg is tailored to rigidize the structure in the fully deployed configuration. Previous experimental and analytical results were very encouraging and indicated that the CHEM foam technology can perform robustly in space as well as in the Earth environment. CHEM structures are described here and their major advantages are identified over other expandable/deployable structures. Although the space community is the original major beneficiary, a number of potential applications are also anticipated for the “earth environment”. CHEM developers strongly believe that this technology has great promise for a host of commercial and bio-medical applications. Some of these potential and already investigated CHEM applications are described in this paper.

Conducting polyaniline (PANi) and their composite nanoparticles were synthesized by both electrochemical and chemical methods. In electrochemical method, PANi and its composite were electro-synthesized in acidic medium (sulphuric acid and oxalic acid) on iron by cyclic voltammetry technique. In chemical method, PANi and its composite were polymerised by a self-assembly method using ammonium peroxydisulfate as an oxydant under supersonic stirring in aqueous medium. The obtained PANi product was characterised by Infra-Red and Raman spectroscopies. The nanostructure of PANi was examined by using Scanning and Transmission Electron Microscopes. The results obtained in electrochemical method shown that PAni nanoparticles could be archived by transformation from its traditional fibrous structure using a bulky dopant as organic acid (oxalic acid), an oxydable subtract (iron) and an additional less electro-active monomer (diamino-naphthalene : DAN). The nano-size of PANi particles synthetized in chemical method could be controlled by using supersonic stirring conditions and participation of additional metallic oxide particles (ZnO).

Smart structures and MEMS have a great potential for strategic and commercial exploitation. India, with its continued emphasis on science and technology, has made forays into this exciting area with well-planned, compact national programmes aimed at technology and systems development. This paper presents the fruits of these national initiatives.