bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ceramics, Transducers
Authors: Uchino Kenji , Ito Yukio 
Published: November 2003

Abstract
The various effects that relate the input—electric field, magnetic field, stress, heat and light—to the output—charge/current, magnetization, strain, temperature, and light are listed. Conducting and elastic materials that generate current and strain outputs, respectively, from input voltage, or stress are sometimes called “trivial” materials. Conversely, pyroelectric and piezoelectric materials that generate an electric field from the input of heat or stress are called “smart” materials. These off‐diagonal couplings have a corresponding converse effect such as electrocaloric and converse piezoelectric effects, and both “sensing” and “actuating” functions can be realized in the same materials. “Intelligent” materials should possess a “drive/control” or “processing” function which is adaptive to the change in environmental conditions, in addition to the actuation and sensing functions. Note that ferroelectric materials exhibit most of these effects, except magnetic‐related phenomena. Thus, the ferroelectrics are said to be very “smart” materials.
The “actuator” in a narrow meaning stands for materials or devices that generate mechanical strain (or stress) output. Solid state actuators use converse piezoelectric, magnetostriction, elasticity, thermal expansion, or photostriction phenomena. A shape‐memory alloy is a kind of thermally expanding material. On the other hand, a “sensor” requires charge/current output in most cases. Thus, conducting/semiconducting, magnetoelectric, piezoelectric, pyroelectric, and photovoltaic materials are used for detecting electric fields, magnetic fields, stress, heat, and light, respectively.
In this sense, piezoelectric materials are most popularly used in smart structures and systems because the same material is applicable to both sensors and actuators, in principle. In this article, we treat mainly piezoelectric transducers, sensors, and actuators. Although, transducers, in general, are devices that convert input energy to a different energy type of output, the piezoelectric “transducer” is often used to denote a device that possesses both sensing and actuating functions, exemplified by underwater sonar.
Characterization of Piezoelectric Ceramic Materials
Authors: Jordan T.L. , Ounaies Z. 
Published: November 2003

AbstractThis article explores piezoelectric ceramics analysis and characterization. The focus is on polycrystalline ceramics; therefore, single crystals, polymeric materials, and organic/inorganic composites are outside the scope of this article. To grasp the behavior of a piezoelectric polycrystalline ceramic thoroughly, a basic understanding of the ceramic itself should not be overlooked. To this end, we have presented a brief introduction of the history of piezoelectricity and a discussion on processing of the ceramic and the development of the constitutive relationships that define the behavior of a piezoelectric material. We have attempted to cover the most common measurement methods and to introduce parameters of interest. Excellent sources for more in‐depth coverage of specific topics can be found in the bibliography. In most cases, we refer to lead zirconate titanate (PZT) to illustrate some of the concepts because it is the most widely used and studied piezoelectric ceramic to date.
Coatings
Authors: Xu Chao‐Nan 
Published: November 2003

AbstractMany materials emit light during the application of a mechanical energy. This phenomenon is usually referred to as mechanoluminescence (ML) or triboluminescence. The more historical term is “triboluminescence.” It stands for tribo‐induced luminescence, and this was the term used for more than a century to refer to light emission induced by any type of mechanical energy. The term “mechanoluminescence” was not proposed until 1978. The prefix “mechano” is correlated to the general mechanical way used for exciting luminescence, including concepts such as deformation, piezo, tribo, stress, cutting, grinding, rubbing, and fracto. In recent years mechanoluminescence (ML) has become the preferred nomenclature. Although the transfer of mechanical stress into light radiation is very complex, successes in experimental applications suggest possible uses of the ML phenomena in stress sensors, mechanical displays, and various smart systems.In general, ML can be divided into fractoluminescence (destructive ML) and deformation luminescence (nondestructive ML); these correspond to the luminescence induced by fracture and mechanical deformation of solid, respectively. Roughly 50% of solid materials gives fractoluminescence by fracture: the well‐known materials include sugar, molecular crystals, alkali halides, quartz, silica glass, phosphors, piezoelectric complex, metals, various minerals, and biomaterials. Recently, the fractoluminescence of rare‐earth complexes was investigated in order to build smart damage sensors capable of simple real‐time detection of the magnitude and location of structural damage within materials. Deformation luminescence can be induced by mechanical deformation without fracture, and this is of interest in nondestructive evaluation. Deformation luminescence can be further divided into plasticoluminescence and elasticoluminescence. The former is produced during plastic deformation of solids, where fracture is not required, and the later is produced during the elastic deformation of solids where neither plastic deformation nor fracture is required. Nondestructive ML due to plastic deformation has been observed in several materials such as colored alkali halides, II–VI semiconductors, and rubbers. However, ML in the elastic region has been observed only for the irradiated alkali halides, and some piezoelectric materials. So far nondestructive luminescence intensities of materials have been reported to be too weak and difficult to repeat, and this has deferred any practical application of the phenomenon. For application of ML in developing new materials, repetitive ML must occur with undiminished intensity.
Chitosan‐Based Gels
Authors: De Yao Kang , Zhao Feng , Li Fang , Yin Yu Ji 
Published: November 2003

AbstractChitosan is a natural biopolymer obtained by deacetylation of chitin, which is produced from marine shellfish, such as crabs, shrimp, fungal cell wells, and other biological sources. Chemically it is a linear cationic poly(β‐(1‐4)‐2‐amino‐2‐deoxy‐D‐glucan) derived from chitin, a poly(β‐(1‐4)‐2‐acetamido‐2‐deoxy‐D‐glucan) by deacetylation. Chitosan is described in terms of the deacetylation degree and average molecular weight. And next to cellulose, it is the second most plentiful biomass and is already known as a biocompatible and biodegradable material. Many researchers have examined tissue response to various chitosan‐based implants. Results indicate that these materials evoke minimal foreign body reactions.Gels consist of 3‐D polymer networks swollen in swellers, whereas hydrogels swell in water. Smart (intelligent) gels (or hydrogels) can swell or contract in response to stimulus changes, e.g., temperature, pH, ionic strength, chemicals, and fields.Chitosan has been used for developing smart gels via network or/and complex formation. Due to their various properties that depend on environmental variables such as pH, ionic strength, and electric field, these materials have potential applications such as biomaterials, separation membranes, and field responsive materials.
Conductive Polymer Composites with Large Positive Temperature Coefficients
Authors: Wong C. P. , Luo Shijian 
Published: November 2003

AbstractConductive polymer composites that contain conductive fillers such as metal powder, carbon black, and other highly conductive particles in a nonconductive polymer matrix have been widely used in electrostatic dissipation (ESD) and electromagnetic interference shielding (EMIS). A special group among electrically conductive polymer composites are conductive polymer composites that have large positive temperature coefficients (PTC), which in some cases are called positive temperature coefficient resistance (PTCR). The resistivity of this kind of composite increases several orders of magnitude in a narrow temperature range. This kind of smart material can change from a conductive material to an insulating material or vice versa upon heating or cooling, respectively. The smartness of this kind material lies in this large PTC amplitude (defined as the ratio of maximum resistivity at the peak or the resistivity right after the sharp increase to the resistivity at 25°C), and also in its reversibility, its ability to adjustment the transition temperature, its low‐temperature resistivity, and high‐temperature resistivity. PTC behavior in a polymer composite was first discovered by Frydman in 1945, but not much attention was paid to it originally. Because Kohler obtained a much higher PTC amplitude from high density polyethylene loaded with carbon black in 1961, this kind of temperature‐sensitive materials has aroused wide research interest and also led to many very useful applications. In this article, the general theories of PTC conductive polymer are introduced. Carbon‐black‐filled conductive polymer composites and their PTC behavior are discussed in more detail, in regard to the effects of fillers, the polymer matrix, and processing conditions, and additives. Applications of this kind of smart temperature‐sensitive material are presented.
Composites, Intrinsically Smart Structures
Authors: Chung D.D.L. 
Published: November 2003

AbstractSmart structures are important because of their use in hazard mitigation, structural vibration control, structural health monitoring, transportation engineering, and thermal control. Research on smart structures has emphasized incorporating of various devices in a structure to provide sensing, energy dissipation, actuation, control, or other functions. Research on smart composites has emphasized incorporating of a smart material in a matrix to enhance smartness or durability. Research on smart materials has emphasized the study of materials (e.g., piezoelectric materials) used for making the devices. However, relatively little attention has been given to the development of structural materials (e.g., concrete and composites) that can inherently provide some of the smart functions, so that the need for embedded or attached devices is reduced or eliminated, thereby lowering cost, enhancing durability, increasing the smart volume, and minimizing mechanical property degradation (which is usually caused by embedded devices).Smart structures are structures that can sense certain stimuli and respond to the stimuli appropriately, somewhat like a human being. Sensing is the most fundamental aspect of a smart structure. A structural composite, which is itself a sensor, is multifunctional.This article focuses on structural composites for smart structures. It addresses cement‐matrix and Polymer‐matrix composites. The smart functions addressed include strain sensing (for structural vibration control and traffic monitoring), damage sensing (both mechanical and thermal damage related to structural health monitoring), temperature sensing (for thermal control, hazard mitigation, and structural performance control), thermoelectricity (for thermal control and saving energy), and vibration reduction (for structural vibration control). These functional abilities of the structural composites have been shown in the laboratory. Applications in the field are forthcoming.
Electrochromic Sol‐Gel Coatings
Authors: Klein L. C. 
Published: November 2003

AbstractCertain inorganic compounds, especially oxides of polyvalent metals, exhibit coloration that depends on the oxidation state of their cations. This property leads to electrochromism, which is a reversible and visible change in transmittance and/or reflectance. The oxidation–reduction reactions are electrochemically induced, using low voltages of the order of ± 1 V dc.In pursuing the development of completely sol‐gel EC devices, physical properties need to be considered, in addition to the ionic conductivity. Of course, the electrolyte has to have high electronic resistivity, high ionic conductivity and no defects. In addition, all of the layers require a film thickness less than about 1000 nm (generally less than 500 nm), high transparency across the visible range, good adhesion between adjacent layers and thermodynamic stability between adjacent layers across a wide electrochemical window. Overall, an EC device should operate under the approximate conditions of +2.5 volts (100 s)/–1.5 volts (100 s) for more than 10,000 cycles at 15 mC/cm2.For practical EC windows, there has been significant recent progress using a variety of technologies. Sol‐gel processing is only one route under investigation. Interest continues in sol‐gel processing because precursors for all of the layers that lead to the appropriate oxide gels are readily available. The resulting gels are inorganic and rigid. In particular, the sol‐gel electrolyte operates while playing the role of a mechanical divider between the electrodes. In addition, sol‐gel processing is a logical batch process for large area coatings. Several studies show that sol‐gel coatings have the required transmittance across the visible light range. Finally, the layers have “no moving parts.”
Fluid Machines
Authors: Bullough W. A. 
Published: November 2003

Abstract
Smart machines can deliver a flexible array of force, velocity, and/or displacement patterns without having their geometry changed in a part‐by‐part sense. Smart fluid machines additionally utilize a liquid as the force‐power‐transmitting medium. Patterns of motion, if not changed by the adjustment of levers, belts, or gear trains, for example, can only be altered by time switching in a sophisticated manner.
Digital technology and the discovery of better magnetic materials brought about a stepper/servomachine operations scenario similar to that of the present timepiece, the digital chromometer, which carries a whole series of side functions (date, time elapsed, calculations, etc.) at the flick of a switch. All are preprogrammed and activated electronically, and they can be operated ad lib as in the calculator or time‐setting functions. A multiplicity of motor‐driven motion shapes can be generated in the same way, successfully and economically. However, not all power‐drive requirements can be achieved by purely electrical means. Some, notably linear, motion or “on‐vehicle” requirements have been traditionally met by fluid power systems.
Third‐age‐type machines will depend on hydraulic power transmission and combine the separate advantages of the mechanical and electromechanical ages in areas where other smart machines cannot compete. The last of these prerequisites derives from the modus operandi of the third‐generation machines' equivalent information technology: digital electronic switching with feedback in order to accommodate control strategies and relative insularity from the effect of any temperature excursions imposed by atmospheric conditions or a varying load cycle.
Intelligent Synthesis of Smart Ceramic Materials
Authors: Lencka Malgorzata M. , Riman Richard E. 
Published: November 2003

AbstractThis article is focus on the hydrothermal synthesis of smart ceramic materials that have a perovskite‐type structure. Perovskite compounds have the general formula ABO3, where the A cation is relatively large and of low valence and the B cation is relatively small.Hydrothermal synthesis involves numerous simultaneous reactions between dissolved and solid species in an aqueous system to form anhydrous multicomponent oxides. Hydrothermal media may provide an effective reaction environment for synthesizing numerous smart ceramic materials from a variety of precursor reagents (e.g., water‐soluble salts, hydroxides, oxides) in the form of polycrystalline solids, thin films, and single crystals.In particular, phase‐pure ceramic materials that have controlled stoichiometry and morphology can be hydrothermally synthesized in a single experimental step from simple and inexpensive precursors at moderate temperatures and pressures far below those required for conventional techniques. It is important to select a precursor system that is both reactive and cost‐effective. However, the reactivity of a precursor system can be judged only by optimizing the processing variables such as reagent (precursor) concentrations and ratios, pH, temperature, and pressure, which can be extremely time‐consuming due to the large number of variables involved. To improve the efficiency of evaluating a precursor system, a comprehensive thermodynamic model that simulates hydrothermal reactions has been developed. This model is a part of the OLI software. The simulation approach discussed here has been validated for numerous perovskite‐type multicomponent oxide systems, which include alkaline‐earth titanates and zirconates, lead titanate, various solid solutions of lead zirconate titanate, lead magnesium niobate, and lead zinc niobate. In this article, modeling and experimental validation of selected hydrothermal systems are presented.
Magnetorheological Fluids
Authors: Henrie Alisa J. Millar , Carlson J. David 
Published: November 2003

AbstractMagnetorheological (MR) materials are a class of materials whose rheological properties may be rapidly varied by applying a magnetic field. This change is in proportion to the magnitude of the magnetic field applied and is immediately reversible. MR material behavior is often modeled by the Bingham plastic model. Advances in the application of MR materials are parallel to the development of advanced MR materials.Because the state of MR materials can be controlled by the strength of an applied magnetic field, it is useful in applications where variable performance is desired. Many smart systems and structures would benefit from the change in viscosity or other material properties of MR materials. Beginning with the commercialization of MR fluid rotary brakes for use in aerobic exercise equipment in 1995, application of magnetorheological material technology in real‐world systems has grown steadily. The past few years have witnessed a blossoming commercialization of MR fluid technology. MR fluid technology has been embraced by a number of manufacturers for inclusion in a diverse spectrum of products that are now commercially available. These application include brakes, dampers, shock absorbers and others.
Pest Control Applications
Authors: Draisey Sherry 
Published: November 2003

Abstract
The smart aspects of the piezoceramic ultrasonic application being used for pest control are just beginning to evolve. Pest control, using ultrasonics, is based on developing a pressure environment which is extremely unpleasant or deadly to the pests in question. The feedback aspect of smart structure applications involves three types of sensing: motion sensors, pressure sensors and sound sensors.
Airborne or land pests, such as some insects, spiders, rodents, and small cats and dogs are driven away by the unpleasant sound created by the noise generated by the ceramic elements. For fluid‐borne pests, the ceramic is driven to create a pressure field that includes cavitation. The release of energy from the collapse of cavitating bubbles provides the source deadly to small microorganisms.
The types of pests that have been effectively deterred by ultrasonic measures are the frequency range that has been successful for these pests, as well as the approximate coverage (or flow rate) across which they are effective are listed. The coverage is directly related to the system size and power.
The Environmental Protection Agency (EPA) has suggested that pest control devices have a deterrent effect of >60% to be considered viable.
Photochromic and Photo‐Thermo‐Refractive Glasses
Authors: Glebov L.B. 
Published: November 2003

Abstract
Inorganic glasses are the main transparent material, which people have long used for observation (windows in buildings, windshields in cars, eyeglasses, prisms and lenses in optical instruments), light delivery (light bulbs, projectors, lasers, optical fibers), and fine arts (crockery, bijouterie, jewelry). The ability of glasses to change coloration after exposure to sunshine was well known since the last century. Photochromic glasses that have completely reversible coloration are made of borosilicate glasses doped with microcrystals of copper and silver halides. These glasses are sensitive to near UV radiation. Photosensitivity can be extended to visible and near IR regions by cooperative breeding of color centers. Induced coloration is a wide band that covers the whole visible region. Photocontrolled waveguides can be fabricated in photochromic glasses. These waveguides can serve as attenuators and mode selectors. Photo‐thermorefractive glasses that have irreversible photoinduced refraction are aluminosilicate glasses doped with silver, cerium, and fluorine. These glasses are sensitive to near UV radiation. Their photosensitivity is comparable with the best organic and inorganic materials, it allows wide variations of exposure because of image amplification in the thermal development process, and it has high diffraction efficiency and high transparency from the UV to the IR region.
Poly(Vinylidene Fluoride) (PVDF) and its Copolymers
Authors: Zhang Q.M. , Bharti Vivek , Kavarnos George 
Published: November 2003

AbstractPoly(vinylidene fluoride) (PVDF) and its family of copolymers are arguably the best‐known examples of a class of high‐performance polymers noted for their remarkable piezoelectric and ferroelectric properties. After more than 30 years of study and development, the piezoelectricity and electromechanical properties of PVDF and its copolymers have been improved markedly. Today this class of polymer still possesses the highest electromechanical responses over a broad temperature range among known synthetic organic materials. Further, when considered along with their easy conformability, flexibility, robustness, and lightness, it is not surprising that electroactive polymers continue to be the focus of interest of the designers of high‐performance electromechanical devices. When PVDF is stretched and poled in a strong electric field, it exhibits piezoelectricity. In its piezoelectric form, PVDF finds use in transducer devices requiring the interconversion of mechanical and electrical energy. Piezoelectric PVDF can be fabricated and used in a variety of sensors and actuators such as artificial muscles and organs, medical imaging, blood‐flow monitors, microphones, smart skins, underwater acoustic transducers, seismic monitors, fluid pumps and valves, surface acoustic wave devices, robots, and tactile sensing devices. P(VDF‐TrFE) copolymers display similar and in some cases even superior properties.Many organic substances in fact exhibit a key ferroelectric property that is called polarization hysteresis. The copolymer of PVDF with trifluoroethylene (TrFE) and tetrafluoroethylene (TFE), however, is the only polymeric system that shows both a well‐defined polarization hysteresis loop and a transition to a paraelectric phase with increased temperature.