Fotonic Sensor Research Articles

Investigation of resonant and energy harvesting characteristics of piezoelectric fiber composite bimorphs

This study investigates the resonant and energy harvesting characteristics of a piezoelectric fiber composite bimorph by using theoretical and experimental techniques, including the full-field optical technique, for the purpose of getting a new perspective on the mechanical and electrical energy transformation ability of piezoelectric composites. A laser Doppler vibrometer, impedance analysis, fotonic sensor, and polyvinylidene fluoride sensor are used in the experiments. Furthermore, an full-field optical technique is also used to measure the resonant frequencies and mode shapes of in-plane and out-of-plane vibrations. Finally, the electrical voltage of the piezoelectric fiber composite bimorph with shaker excitation is measured and used for a light-emitting diode. The shaker input voltage, output voltage of the piezoelectric structure, and light intensity are all measured to find out the power generation capacity of piezoelectric composite. The relationship between the energy harvesting ability and excitation methods, the input voltage value, and frequency are obtained through analyses. From the experiment results, it is indicated that the most efficient modes are affected by the excitation method and the location of an excitation point of the shaker. This study helps in understanding the resonant characteristics as well as the energy harvesting capability of piezoelectric composite.

Transient behavior of a cantilever plate subjected to impact loading: Theoretical analysis and experimental measurement

This study employed theoretical analysis and experimental measurements in an exploration of the transient behavior of a cantilever plate subjected to a dynamic impact force. The solution of transient displacement is established as a product of the time function and mode shapes for the cantilever plate. The superposition method was used to obtain the mode shapes and resonant frequencies for free vibrations, and the orthogonality of the mode shapes was used to determine the time function. We demonstrate that the results of transient behaviors including transient displacement, strain, velocity and acceleration of the cantilever plate can be explicitly presented in closed forms. In the experiment, the dynamic external force was produced by the impact of a steel ball on the cantilever plate, and a pair of Polyvinylidene fluoride (PVDF) sensors are used to measure the force history of the impact loading. Fotonic sensor (FS) was also used to obtain the time signals of transient displacement, and PVDF film sensors were used to determine transient strain in the cantilever plate.Our results obtained in the theoretical analysis are highly consistent with experimental measurement and FEM simulations in the time domain. This is a clear demonstration of the effectiveness of pairing theoretical analysis with impact loading histories measured using PVDF sensors in the representation of transient wave propagation behavior in a cantilever plate. Based on the proposed theoretical solution, we established the relationship between transient behaviors and vibrational characteristics that allow us to get more information of the physical phenomenon of the transient response. In transient signal, the contribution of each mode is related to the position of impact point and observation point. The position of exciting force and observation near the nodal lines of particular mode shapes can reduce the contribution of those modes in the transient waveform. We also investigated the influence on the transient response of a cantilever plate subjected to various impact loading duration, and indicate that the amplitude of transient displacement after the release of external force is depended on the impact force duration. Setting the force released at the time of period for specific mode, which provide the maximum contribution, can suppress the amplitude of oscillation in subsequent transient displacement.

Simultaneous measurement of dynamic displacement and strain in a single fiber using coarse wavelength-division multiplexing and fiber Bragg-grating filter-based sensing system

Displacement and strain, two of the most important physical quantities in experimental solid mechanics, are seldomly measured simultaneously in a single experimental configuration. In order to provide and improve corresponding sensing techniques, an experimental setup system for simultaneous measurement of dynamic displacement and strain on a flexible cantilever beam using two fiber Bragg gratings (FBGs) in a single fiber is proposed. To realize high-speed multiplexing and demodulation, a configuration incorporating a coarse wavelength-division multiplexing (CWDM) technique and an FBG transmission filter is implemented. The cantilever beam is subjected to steel-ball impact from which the dynamic multipoint displacement/strain sensing performances of the CWDM and FBG filter-based sensing system are demonstrated. Experimental results in temporal and frequency domain are compared with those obtained by the finite element method (FEM) predictions based on identification of the impact-loading history. A noncontact Fotonic displacement sensor and a polyvinylidene-fluoride film (PVDF) strain sensor are also used for comparison. With transient and resonant frequency simulations conducted by the FEM, loading effects of the sensing system are examined. The results obtained in this study indicate that the proposed CWDM and FBG filter-based sensing system is capable of performing simultaneous multipoint displacement/strain measurements in a single fiber with large bandwidth, high sensitivity, and low intensity loss.

Achieving high performance electric field induced strain: a rational design of hyperbranched aromatic polyamide functionalized graphene-polyurethane dielectric elastomer composites.

Dielectric elastomers have great potentials as flexible actuators in micro-electromechanical systems (MEMS) due to their large deformation, light weight, mechanical compliancy, and low cost. The low dielectric constant of these elastomers requires a rather high voltage electric field, which has greatly limited their applications. In this work, a diaphragm-type flexible microactuator comprising a hyperbranched aromatic polyamide functionalized graphene (HAPFG) filler embedded into the polyurethane (PU) dielectric elastomer matrix is described. The rational designed HAPFG sheets exhibits uniform dispersion in PU matrix and strong adhesion with the matrix by hydrogen-bond coupling. Consequently, the HAPFG-PU composites possess high dielectric performance and low loss modulus. The effect of hyperbranched aromatic polyamide functionalized graphene on high voltage electric field induced strain was experimentally investigated using the Fotonic sensor. The high electric field response of the composite was discussed by applying different kinds of alternating-current field. In addition, a comparison of the breakdown strength between the HAPFG-PU composite and the pure PU was carried out.

Application of a Fiber Bragg Grating-Based Sensing System on Investigating Dynamic Behaviors of a Cantilever Beam Under Impact or Moving Mass Loadings

By setting up a fiber Bragg grating (FBG) displacement and strain sensing system, this paper experimentally investigates dynamic behaviors of a cantilever beam under impact or moving mass loadings. Dynamic sensing ability of the FBG displacement sensor is demonstrated by simultaneously measuring with a noncontact Fotonic sensor. Responses obtained from the FBG strain sensor are compared with those obtained from polyvinylidene fluoride film sensors and a strain gauge. First, an impact loading is generated by an impact hammer, and transient out-of-plane displacement responses obtained from the proposed FBG displacement sensor are compared with finite element simulations. Then, vibrations of the cantilever beam subjected to impact loadings by a steel ball are investigated. Finally, with a high-speed camera to detect the moving speed, experimental study of the cantilever beam under a moving mass is performed. By using the FBG displacement and strain sensing system, three kinds of modes of the cantilever beam (i.e., bending modes, lateral bending modes, and torsional modes) are detected under impact or moving mass loadings. With the high sensitivity of the proposed FBG sensing system, relationships between the transient responses induced by impact or moving mass loading and the vibration modes are discussed.

POLYVINYLIDENE FLUORIDE AND ZINC OXIDE SMART COMPOSITE MATERIAL

This work aimed at fabrication and electromechanical characterization of a smart material system composed of electroactive polymer and ceramic materials. The idea of composite material system is on account of complementary characteristics of the polymer and ceramic for flexibility and piezoelectric activity. Our preliminary work included Polyvinylidene Fluoride (PVDF) as the flexible piezoelectric polymer, and Zinc Oxide (ZnO) as the piezoelectric ceramic brittle, but capable to respond strains without poling. Two alternative processes were investigated. The first process makes use of ZnO fibrous formation achieved by sintering PVA/zinc acetate precursor fibers via electrospinning. Highly brittle fibrous ZnO mat was dipped into a PVDF polymer solution and then pressed to form pellets. The second process employed commercial ZnO nanopowder material. The powder was mixed into a PVDF/acetone polymer solution, and the resultant paste was pressed to form pellets. The free standing composite pellets with electrodes on the top and bottom surfaces were then subjected to sinusoidal electric excitation and response was recorded using a fotonic sensor. An earlier work on electrospun PVDF fiber mats was also summarized here and the electromechanical characterization is reported.

Electromechanical measurements of electric field-induced displacements of fibers

In this paper we report on a development of a new method for measurements of electric field-induced displacements in a cylindrical geometry (optical fiber with the deposited piezoelectric film). The measurement setup is based on a commercially available Fotonic Sensor MTI 2000 (MTI Inc.). Major disadvantages of measurement by standard techniques (e.g., interferometry) such as low reflectivity, high roughness of the coating resulting in poor fringe quality, and big displacement range are successfully avoided using a special configuration of an optical probe and a sample. The method allows performing investigations of electromechanically induced vibrations in a broad frequency range (from 0 up to 150 kHz) and various combinations of ac and dc voltages. The capabilities of the proposed method are validated by strain measurements of an optical fiber cantilever beam covered by Pb(Zr,Ti)O(3) thick film.

Fiber-optic based method for the measurements of electric-field induced displacements in ferroelectric materials

A novel technique for the measurements of electric field-induced displacements in ferroelectric materials is presented. The method relies on a high sensitivity of the fiber-optic probe (Fotonic Sensor™, MTI Inc.) that measures the displacement of a specially designed cantilever beam having both electrical and mechanical contact with deforming sample. In this way, the major disadvantages of the standard Fotonic Sensor technique can be avoided. The method provides relatively high sensitivity (down to ∼4Å), high stability (7% over 8h), and sufficiently broad frequency range. The capabilities of the proposed measurement setup are validated by the strain measurements in bulk Pb(Zr,Ti)O3(PZT) ceramics and thin films.

Measurements of Piezoelectric Properties of Ferroelectric Thick Films by Fotonic Sensor

A development of method of piezoelectric measurements of thick film and bulk samples by a commercially available Fotonic Sensor TM is reported. The main problem of using this technique is a high requirement to the electrode quality and an overestimation of the piezoelectric coefficients due to bending effects. In this work, both problems were successfully solved by using special mechanical interface (cantilever beam) that transfers mechanical displacement from the moving piezoelectric surface to the mirror. The capabilities of the piezoelectric measurement setup are validated by the measurements in both bulk ceramics and thick Pb(Zr,Ti)O3 films.

Fabrication and Performance of Piezoelectric Tubes for Cylindrical Ultrasonic Micromotor

The piezoelectric ceramic tubular transducer is a functional component of the cylindrical ultrasonic micromotor. In this paper, electrophorectic deposition (EPD) method was employed to fabricate the tubular transducer using a modified hard PZT ceramic material 0.95Pb(Zr0.52Ti0.48)O3 · 0.03BiFeO3 · 0.02Ba(Cu0.5 W0.5)O3 + 0.5 wt%MnO2. Characterization of the piezoelectric tube was performed using SEM and X-ray radiography. The piezoelectric constant d 31 of the tubular transducer was also determined to be 5.58 × 10−11 m/v using a ferroelectric tester and a fotonic sensor. The equations for static bending displacement with clamped-free and free-free end conditions were theoretically developed, analyzed and experimentally verified.

Measurements of wineglass resonance using a fiber-optic probe

A fiber-optic probe (MTI-2000 Fotonic Sensor) is used by Central Washington University physics students to measure the peak displacement of such vibrating surfaces as acoustically driven wineglasses, parametrically shaken liquids, and soap films. This presentation will consist of a brief description of the fiber-optic measurement system, a discussion of its advantages and limitations, and sampling of some recent data obtained by students.

An experimental study on solitary waves of a rotating disk

This paper has been studied on the solitary wave phenomena on the flexible rotating disk by experiment of measuring the separation of solitons. The phenomena have been discovered recently by Crandall and Boulahbal in 1995. They have shown some pictures of solitary waves on a flexible rotating disk by using a high speed camera and fotonic sensor. But there is no theory to explain and predict such solitary waves on a flexible rotating disk with a thin film of fluid. In order to establish this theory and to explain these phenomena, more experiments are needed to describe such waves. This paper attempts to provide such necessary experiments by studying the relations of air inflow gaps, radius of rotating disk and its rotating speed. The separation of solitons has been measured by a fiber optic displacement sensor at each speed. Some conclusions have been obtained from this experiment to describe this new phenomena of solitary waves on a rotating disk. It may be a very qualitative description rather than a quantitative prediction using a mathematical model. However we have measured the separation and taken photographs with a high speed camera; therefore this conclusion could be useful in understanding the phenomena and may contribute to future work.

Role of Nitric Oxide Production through M2-Cholinergic Receptors in Cultured Rat Ventricular Myocytes

We previously reported that carbachol (CCh) caused the enhancement of NO production coinciding with negative chronotropy in cultured rat ventricular myocytes. In this study, we examined which subtype of muscarinic cholinergic receptor mediated these effects of CCh by measuring the NOx production with an HPLC-Griess reaction system and monitoring the beating with a Fotonic Sensor. The enhancement of NO production and negative chronotropy by 10−4M CCh stimulation were significantly inhibited by 10−6M atropine, 10−6M methoctramine, 3 × 10−4M L-NMMA, and 10−5M methylene blue. On the other hand, 10−6M pirenzepine and 10−6M HHSiD had no influence on the negative chronotropy by 10−4M CCh stimulation. Both 10−6M pirenzepine and 10−6M HHSiD suppressed the enhancement of NO production by 10−4M CCh stimulation slightly though not statistically. In addition, the m2 cholinergic receptor gene was expressed in our cell preparations, as demonstrated by reverse-transcriptase/PCR analysis. We concluded that M2-cholinergic receptor-mediated negative chronotropy may be due in part to activation of the NO-signaling pathway in cultured rat ventricular myocytes.

Debonding of photoresists by organic solvents

Chlorofluorocarbons (CFCs) have been widely used in the printed circuit board industry for many decades. However, the growing concern regarding their ozone depleting properties has demanded a ban on these solvents and consequently brought forth the search for environmentally friendly alternatives. In printed circuit board technology, methyl chloroform and methylene chloride have been widely utilized as solvents for developing and stripping, respectively, radiation sensitive materials useful in creating fine line circuitry patterns. The solubility of unexposed and exposed T168 resist in selected solvents or solvent mixtures at various temperatures is described here. Results addressing the ease of removal of such solvent based resists using environmentally friendly alternatives are presented. Debonding of the polymer layer from the underlying substrate was observed by monitoring the deflection of the composite strip immersed in the solvent using a Fotonic Sensor accessory. Debonding time, identified as the necessary time to remove the photoresist from such surfaces, can vary with temperature, solvent, photoresist type or thickness, and exposure energy. © 1996 John Wiley & Sons, Inc.

Piezoelectric Characterization of Bulk and Thin Film Ferroelectric Materials using Fiber Optics

AbstractIn this study, the use of a fiber optic technique for the measurement of the piezoelectric properties of ferroelectric bulk and thin film samples was investigated. The strain and piezoelectric properties (namely the d33 coefficients) were measured using the MTI-2000 Fotonic Sensor, which uses the principle of the optical lever to resolve very small changes in sample displacement (1 Å). Using this technique, we were able to detect the very small strains associated with the converse piezoelectric effect for PVDF films and bulk PZT samples, and correlate the results with data acquired from direct piezoelectric effect measurement. Comparison of the data sets prove that the optical lever would be a useful optical technique for measuring of the d33 values of ceramic thin films, such as BaTiO3, ZnO, and PZT.

Reversible Inhibition of Gap Junctional Intercellular Communication, Synchronous Contraction, and Synchronism of Intracellular Ca2+ Fluctuation in Cultured Neonatal Rat Cardiac Myocytes by Heptanol

We analyzed by Fotonic Sensor, a fiber-optic displacement measurement instrument, the effects of heptanol on synchronized contraction of primary neonatal rat cardiac myocytes cultured at confluent density. We also examined the effect of heptanol on the changes in gap junctional intercellular communication by using the microinjection dye transfer method, and on intercellular Ca2+ fluctuation by confocal laser scanning microscopy of myocytes loaded with the fluorescent Ca2+ indicator fluo 3. In addition, we studied expression, phosphorylation, and localization of the major cardiac gap junction protein connexin 43 (Cx43) using immunofluorescence and Western blotting. At Day 6 of culture, numerous myocytes exhibited spontaneous, synchronous contractions, excellent dye coupling, and synchronized intracellular Ca2+ fluctuations. We treated the cells with 1.5, 2.0, 2.5, and 3.0 mmol/liter heptanol. With 1.5 mmol/liter heptanol, we could not observe significant effects on spontaneous contraction of myocytes. At 3.0 mmol/liter, the highest concentration used in the current experiment, heptanol inhibited synchronous contractions and even after washing out of heptanol, synchronous contraction was not rapidly recovered. On the other hand, at the intermediate concentrations of 2.0 and 2.5 mmol/liter, heptanol reversely inhibited synchronized contraction, gap junctional intercellular communication, and synchronization of intracellular Ca2+ fluctuations in the myocytes without preventing contraction and changes of intracellular Ca2+ in individual cells. Brief exposure (5-20 min) to heptanol (2.0 mmol/liter) did not cause detectable changes in the expression, phosphorylation, or localization of Cx43, despite strong inhibition of gap junctional intercellular communication. These results suggest that gap junctional intercellular communication plays an important role in synchronous intracellular Ca2+ fluctuations, which facilitate synchronized contraction of cardiac myocytes.

S3-3 - α1,-Adrcnoceptor subtypes which participate in the contractile response of rat cardiac myocytes: Evaluation by a new Fotonic Sensor

S3-3 - α1,-Adrcnoceptor subtypes which participate in the contractile response of rat cardiac myocytes: Evaluation by a new Fotonic Sensor

UV/ozone cleaning of a replica grating

UV/ozone cleaning was evaluated for cleaning a carbon-contaminated replica grating. Replica optics represent a challenging test of any cleaning process because of the potential for damage to the epoxy layer which can severely degrade the surface figure and finish. A badly contaminated replica grating was divided into three sections for this study. One section was cleaned using a mercury lamp, another section was cleaned using a deuterium lamp, and the third section was left as a control. The results were evaluated using a Ronchi test to determine figure error, a Fotonic sensor to estimate reflectivity, and a microscopic evaluation using a Nomarski objective to look for surface damage. Surface roughness measurements were also performed with a Micromap surface profiler. The results indicated that the surface figure and finish were not significantly degraded, and the surface figure was actually improved compared to the contaminated condition. The visible light reflectivity was fully restored in the areas that were cleaned.

The Expression, Phosphorylation, and Localization of Connexin 43 and Gap-Junctional Intercellular Communication during the Establishment of a Synchronized Contraction of Cultured Neonatal Rat Cardiac Myocytes

We analyzed the expression, phosphorylation, and localization of the major cardiac gap-junction protein connexin 43 (Cx43) during the establishment of a synchronized contraction in confluent monolayers of primary cultured neonatal rat cardiac myocytes, combined with a functional assay of gap junctions by the microinjection-dye transfer method. Monitoring of the beating rate and synchronization by Fotonic Sensor showed that at Day 1 of culture cardiac myocytes contracted spontaneously but irregularly, that the contractile rate increased with culture time, and that a synchronized contraction was gradually formed. At Day 7, the confluent cells exhibited synchronous contraction with a relatively constant rate (125 ± 20 beats/min). Cardiac myocytes expressed a large amount of Cx43 mRNA even at Day 1 and maintained the expression until at least Day 7. Immunofluorescence of Cx43 showed that the localization of Cx43-positive spots was mostly restricted to cell-cell contacts between myocytes and that few Cx43-positive spots were present between myocytes and fibroblasts or between fibroblasts. The amount of Cx43 protein, the proportion of phosphorylated forms to the nonphosphorylated one, and the number and total area of Cx43-positive spots increased with culture time. Gap-junctional intercellular communication measured by dye transfer assay was also increased with culture time and correlated well with the number and total area of Cx43-positive spots. Our systematic study suggests that a concerted action of the expression, phosphorylation, and localization of Cx43 and gap-junctional intercellular communication plays a major role in the reestablishment of synchronous beating of cultured neonatal rat cardiac myocytes.

Hypoxia inverts the negative chronotropic response to norepinephrine in normoxia in cultured neonatal rat cardiac myocytes: role of the α1 adrenergic signal transduction system

In the present study, we investigated the effect of hypoxia on the chronotropic response to norepinephrine (NE) of cultured neonatal rat ventricular myocytes. We measured beating of myocytes with the Fotonic sensor TM , using a newly developed method for a noncontact displacement measurement. The beating rate counted with the sensor had a high correlation coefficient with that counted visually under a microscope ( r = 0.997, P < 0.01). NE concentrations of 10 −8–10 −4 M caused negative chronotropy dose dependently in the presence of 5×10 −7 M propranolol. NE-induced chronotropy was completely antagonized by 10 −6 M prazosin. Three hours hypoxia decreased the spontaneous beating rate 40% ( P < 0.01). Negative chronotropy induced by 10 −4 M NE in normoxia was inverted to positive and was antagonized by prazosin. Hypoxia increased the basal level of inositol 1,4,5-trisphosphate (Ins(1,4,5)P 3) to 190% ( P < 0.01), while NE-stimulated Ins(1,4,5)P 3 production was significantly suppressed. Immunoblotting analysis of G protein subunits demonstrated no quantitative changes in Giα, Gqα, Goα and G βcommon subunits in hypoxia. In a saturation binding assay with [ 3H]prazosin, K d values were increased to 152% by hypoxia ( P < 0.05) without significant change in B max. Basal activity of low K m-GTPase was increased to 122% by hypoxia ( P < 0.05). These results suggest that the hypoxia-induced increase in low- K m GTPase activity, which could stimulate phospholipase C by an activated α GTP subunit of G protein and consequently induce receptor-independent increase in Ins(1,4,5)P 3, may be responsible for the inversion of the NE-induced negative chronotropic response in normoxia.