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Sample records for acoustic waves saws

  1. Surface acoustic wave (SAW) vibration sensors.

    PubMed

    Filipiak, Jerzy; Solarz, Lech; Steczko, Grzegorz

    2011-01-01

    In the paper a feasibility study on the use of surface acoustic wave (SAW) vibration sensors for electronic warning systems is presented. The system is assembled from concatenated SAW vibration sensors based on a SAW delay line manufactured on a surface of a piezoelectric plate. Vibrations of the plate are transformed into electric signals that allow identification of the sensor and localization of a threat. The theoretical study of sensor vibrations leads us to the simple isotropic model with one degree of freedom. This model allowed an explicit description of the sensor plate movement and identification of the vibrating sensor. Analysis of frequency response of the ST-cut quartz sensor plate and a damping speed of its impulse response has been conducted. The analysis above was the basis to determine the ranges of parameters for vibrating plates to be useful in electronic warning systems. Generally, operation of electronic warning systems with SAW vibration sensors is based on the analysis of signal phase changes at the working frequency of delay line after being transmitted via two circuits of concatenated four-terminal networks. Frequencies of phase changes are equal to resonance frequencies of vibrating plates of sensors. The amplitude of these phase changes is proportional to the amplitude of vibrations of a sensor plate. Both pieces of information may be sent and recorded jointly by a simple electrical unit.

  2. Surface-acoustic-wave (SAW) flow sensor

    NASA Astrophysics Data System (ADS)

    Joshi, Shrinivas G.

    1991-03-01

    The use of a surface-acoustic-wave (SAW) device to measure the rate of gas flow is described. A SAW oscillator heated to a suitable temperature above ambient is placed in the path of a flowing gas. Convective cooling caused by the gas flow results in a change in the oscillator frequency. A 73-MHz oscillator fabricated on 128 deg rotated Y-cut lithium niobate substrate and heated to 55 C above ambient shows a frequency variation greater than 142 kHz for flow-rate variation from 0 to 1000 cu cm/min. The output of the sensor can be calibrated to provide a measurement of volume flow rate, pressure differential across channel ports, or mass flow rate. High sensitivity, wide dynamic range, and direct digital output are among the attractive features of this sensor. Theoretical expressions for the sensitivity and response time of the sensor are derived. It is shown that by using ultrasonic Lamb waves propagating in thin membranes, a flow sensor with faster response than a SAW sensor can be realized.

  3. Surface Acoustic Wave (SAW) Resonators for Monitoring Conditioning Film Formation.

    PubMed

    Hohmann, Siegfried; Kögel, Svea; Brunner, Yvonne; Schmieg, Barbara; Ewald, Christina; Kirschhöfer, Frank; Brenner-Weiß, Gerald; Länge, Kerstin

    2015-05-21

    We propose surface acoustic wave (SAW) resonators as a complementary tool for conditioning film monitoring. Conditioning films are formed by adsorption of inorganic and organic substances on a substrate the moment this substrate comes into contact with a liquid phase. In the case of implant insertion, for instance, initial protein adsorption is required to start wound healing, but it will also trigger immune reactions leading to inflammatory responses. The control of the initial protein adsorption would allow to promote the healing process and to suppress adverse immune reactions. Methods to investigate these adsorption processes are available, but it remains difficult to translate measurement results into actual protein binding events. Biosensor transducers allow user-friendly investigation of protein adsorption on different surfaces. The combination of several transduction principles leads to complementary results, allowing a more comprehensive characterization of the adsorbing layer. We introduce SAW resonators as a novel complementary tool for time-resolved conditioning film monitoring. SAW resonators were coated with polymers. The adsorption of the plasma proteins human serum albumin (HSA) and fibrinogen onto the polymer-coated surfaces were monitored. Frequency results were compared with quartz crystal microbalance (QCM) sensor measurements, which confirmed the suitability of the SAW resonators for this application.

  4. Surface Acoustic Wave (SAW) Resonators for Monitoring Conditioning Film Formation

    PubMed Central

    Hohmann, Siegfried; Kögel, Svea; Brunner, Yvonne; Schmieg, Barbara; Ewald, Christina; Kirschhöfer, Frank; Brenner-Weiß, Gerald; Länge, Kerstin

    2015-01-01

    We propose surface acoustic wave (SAW) resonators as a complementary tool for conditioning film monitoring. Conditioning films are formed by adsorption of inorganic and organic substances on a substrate the moment this substrate comes into contact with a liquid phase. In the case of implant insertion, for instance, initial protein adsorption is required to start wound healing, but it will also trigger immune reactions leading to inflammatory responses. The control of the initial protein adsorption would allow to promote the healing process and to suppress adverse immune reactions. Methods to investigate these adsorption processes are available, but it remains difficult to translate measurement results into actual protein binding events. Biosensor transducers allow user-friendly investigation of protein adsorption on different surfaces. The combination of several transduction principles leads to complementary results, allowing a more comprehensive characterization of the adsorbing layer. We introduce SAW resonators as a novel complementary tool for time-resolved conditioning film monitoring. SAW resonators were coated with polymers. The adsorption of the plasma proteins human serum albumin (HSA) and fibrinogen onto the polymer-coated surfaces were monitored. Frequency results were compared with quartz crystal microbalance (QCM) sensor measurements, which confirmed the suitability of the SAW resonators for this application. PMID:26007735

  5. Separation of biological cells in a microfluidic device using surface acoustic waves (SAWs)

    NASA Astrophysics Data System (ADS)

    Ai, Ye; Marrone, Babetta L.

    2014-03-01

    In this study, a surface acoustic wave (SAW)-based microfluidic device has been developed to separate heterogeneous particle or cell mixtures in a continuous flow using acoustophoresis. The microfluidic device is comprised of two components, a SAW transducer and a microfluidic channel made of polydimethylsiloxane (PDMS). The SAW transducer was fabricated by patterning two pairs of interdigital electrodes on a lithium niobate (LiNbO3) piezoelectric substrate. When exciting the SAW transducer by AC signals, a standing SAW is generated along the cross-section of the channel. Solid particles immersed in the standing SAW field are accordingly pushed to the pressure node arising from the acoustic radiation force acting on the particles, referring to the acoustic particle-focusing phenomenon. Acoustic radiation force highly depends on the particle properties, resulting in different acoustic responses for different types of cells. A numerical model, coupling the piezoelectric effect in the solid substrate and acoustic pressure in the fluid, was developed to provide a better understanding of SAW-based particle manipulation. Separation of two types of fluorescent particles has been demonstrated using the developed SAW-based microfluidic device. An efficient separation of E. coli bacteria from peripheral blood mononuclear cell (PBMC) samples has also been successfully achieved. The purity of separated E. coli bacteria and separated PBMCs were over 95% and 91%, respectively, obtained by a flow cytometric analysis. The developed microfluidic device can efficiently separate E. coli bacteria from biological samples, which has potential applications in biomedical analysis and clinical diagnosis.

  6. Hybrid Surface Acoustic Wave- Electrohydrodynamic Atomization (SAW-EHDA) For the Development of Functional Thin Films

    PubMed Central

    Choi, Kyung Hyun; Kim, Hyun Bum; Ali, Kamran; Sajid, Memoon; Uddin Siddiqui, Ghayas; Chang, Dong Eui; Kim, Hyung Chan; Ko, Jeong Beom; Dang, Hyun Woo; Doh, Yang Hoi

    2015-01-01

    Conventional surface acoustic wave - electrostatic deposition (SAW-ED) technology is struggling to compete with other thin film fabrication technologies because of its limitation in atomizing high density solutions or solutions with strong inter-particle bonding that requires very high frequency (100 MHz) and power. In this study, a hybrid surface acoustic wave - electrohydrodynamic atomization (SAW-EHDA) system has been introduced to overcome this problem by integrating EHDA with SAW to achieve the deposition of different types of conductive inks at lower frequency (19.8 MHZ) and power. Three materials, Poly [2-methoxy-5-(2-ethylhexyloxy)-1, 4-phenylenevinylene] (MEH-PPV), Zinc Oxide (ZnO), and Poly(3, 4-ethylenedioxythiophene):Polystyrene Sulfonate (PEDOT:PSS) have been successfully deposited as thin films through the hybrid SAW-EHDA. The films showed good morphological, chemical, electrical, and optical characteristics. To further evaluate the characteristics of deposited films, a humidity sensor was fabricated with active layer of PEDOT:PSS deposited using the SAW-EHDA system. The response of sensor was outstanding and much better when compared to similar sensors fabricated using other manufacturing techniques. The results of the device and the films’ characteristics suggest that the hybrid SAW-EHDA technology has high potential to efficiently produce wide variety of thin films and thus predict its promising future in certain areas of printed electronics. PMID:26478189

  7. Virtual membrane for filtration of particles using surface acoustic waves (SAW).

    PubMed

    Fakhfouri, Armaghan; Devendran, Citsabehsan; Collins, David J; Ai, Ye; Neild, Adrian

    2016-09-21

    Surface acoustic wave (SAW) based particle manipulation is contactless, versatile, non-invasive and biocompatible making it useful for biological studies and diagnostic technologies. In this work, we present a sensitive particle sorting system, termed the virtual membrane, in which a periodic acoustic field with a wavelength on the order of particle dimensions permits size-selective filtration. Polystyrene particles that are larger than approximately 0.3 times the acoustic half-wavelength experience a force repelling them from the acoustic field. If the particle size is such that, at a given acoustic power and flow velocity, this repulsive force is dominant over the drag force, these particles will be prohibited from progressing further downstream (i.e. filtered), while smaller particles will be able to pass through the force field along the pressure nodes (akin to a filter's pores). Using this mechanism, we demonstrate high size selectivity using a standing SAW generated by opposing sets of focused interdigital transducers (FIDTs). The use of FIDTs permits the generation of a highly localized standing wave field, here used for filtration in μl min(-1) order flow rates at 10s of mW of applied power. Specifically, we demonstrate the filtration of 8 μm particles from 5 μm particles and 10.36 μm particles from 7.0 μm and 5.0 μm particles, using high frequency SAW at 258 MHz, 192.5 MHz, and 129.5 MHz, respectively.

  8. Detection/classification/quantification of chemical agents using an array of surface acoustic wave (SAW) devices

    NASA Astrophysics Data System (ADS)

    Milner, G. Martin

    2005-05-01

    ChemSentry is a portable system used to detect, identify, and quantify chemical warfare (CW) agents. Electro chemical (EC) cell sensor technology is used for blood agents and an array of surface acoustic wave (SAW) sensors is used for nerve and blister agents. The combination of the EC cell and the SAW array provides sufficient sensor information to detect, classify and quantify all CW agents of concern using smaller, lighter, lower cost units. Initial development of the SAW array and processing was a key challenge for ChemSentry requiring several years of fundamental testing of polymers and coating methods to finalize the sensor array design in 2001. Following the finalization of the SAW array, nearly three (3) years of intensive testing in both laboratory and field environments were required in order to gather sufficient data to fully understand the response characteristics. Virtually unbounded permutations of agent characteristics and environmental characteristics must be considered in order to operate against all agents and all environments of interest to the U.S. military and other potential users of ChemSentry. The resulting signal processing design matched to this extensive body of measured data (over 8,000 agent challenges and 10,000 hours of ambient data) is considered to be a significant advance in state-of-the-art for CW agent detection.

  9. Highly focused high-frequency travelling surface acoustic waves (SAW) for rapid single-particle sorting.

    PubMed

    Collins, David J; Neild, Adrian; Ai, Ye

    2016-02-07

    High-speed sorting is an essential process in a number of clinical and research applications, where single cells, droplets and particles are segregated based on their properties in a continuous flow. With recent developments in the field of microscale actuation, there is increasing interest in replicating the functions available to conventional fluorescence activated cell sorting (FACS) flow cytometry in integrated on-chip systems, which have substantial advantages in cost and portability. Surface acoustic wave (SAW) devices are ideal for many acoustofluidic applications, and have been used to perform such sorting at rates on the order of kHz. Essential to the accuracy of this sorting, however, is the dimensions of the region over which sorting occurs, where a smaller sorting region can largely avoid inaccurate sorting across a range of sample concentrations. Here we demonstrate the use of flow focusing and a highly focused SAW generated by a high-frequency (386 MHz), 10 μm wavelength set of focused interdigital transducers (FIDTs) on a piezoelectric lithium niobate substrate, yielding an effective sorting region only ~25 μm wide, with sub-millisecond pulses generated at up to kHz rates. Furthermore, because of the use of high frequencies, actuation of particles as small as 2 μm can be realized. Such devices represent a substantial step forward in the evolution of highly localized forces for lab-on-a-chip microfluidic applications.

  10. Surface Acoustic Waves (SAW)-Based Biosensing for Quantification of Cell Growth in 2D and 3D Cultures

    PubMed Central

    Wang, Tao; Green, Ryan; Nair, Rajesh Ramakrishnan; Howell, Mark; Mohapatra, Subhra; Guldiken, Rasim; Mohapatra, Shyam Sundar

    2015-01-01

    Detection and quantification of cell viability and growth in two-dimensional (2D) and three-dimensional (3D) cell cultures commonly involve harvesting of cells and therefore requires a parallel set-up of several replicates for time-lapse or dose–response studies. Thus, developing a non-invasive and touch-free detection of cell growth in longitudinal studies of 3D tumor spheroid cultures or of stem cell regeneration remains a major unmet need. Since surface acoustic waves (SAWs) permit mass loading-based biosensing and have been touted due to their many advantages including low cost, small size and ease of assembly, we examined the potential of SAW-biosensing to detect and quantify cell growth. Herein, we demonstrate that a shear horizontal-surface acoustic waves (SH-SAW) device comprising two pairs of resonators consisting of interdigital transducers and reflecting fingers can be used to quantify mass loading by the cells in suspension as well as within a 3D cell culture platform. A 3D COMSOL model was built to simulate the mass loading response of increasing concentrations of cells in suspension in the polydimethylsiloxane (PDMS) well in order to predict the characteristics and optimize the design of the SH-SAW biosensor. The simulated relative frequency shift from the two oscillatory circuit systems (one of which functions as control) were found to be concordant to experimental data generated with RAW264.7 macrophage and A549 cancer cells. In addition, results showed that SAW measurements per se did not affect viability of cells. Further, SH-SAW biosensing was applied to A549 cells cultured on a 3D electrospun nanofiber scaffold that generate tumor spheroids (tumoroids) and the results showed the device's ability to detect changes in tumor spheroid growth over the course of eight days. Taken together, these results demonstrate the use of SH-SAW device for detection and quantification of cell growth changes over time in 2D suspension cultures and in 3D cell

  11. Surface Acoustic Waves (SAW)-Based Biosensing for Quantification of Cell Growth in 2D and 3D Cultures.

    PubMed

    Wang, Tao; Green, Ryan; Nair, Rajesh Ramakrishnan; Howell, Mark; Mohapatra, Subhra; Guldiken, Rasim; Mohapatra, Shyam Sundar

    2015-12-19

    Detection and quantification of cell viability and growth in two-dimensional (2D) and three-dimensional (3D) cell cultures commonly involve harvesting of cells and therefore requires a parallel set-up of several replicates for time-lapse or dose-response studies. Thus, developing a non-invasive and touch-free detection of cell growth in longitudinal studies of 3D tumor spheroid cultures or of stem cell regeneration remains a major unmet need. Since surface acoustic waves (SAWs) permit mass loading-based biosensing and have been touted due to their many advantages including low cost, small size and ease of assembly, we examined the potential of SAW-biosensing to detect and quantify cell growth. Herein, we demonstrate that a shear horizontal-surface acoustic waves (SH-SAW) device comprising two pairs of resonators consisting of interdigital transducers and reflecting fingers can be used to quantify mass loading by the cells in suspension as well as within a 3D cell culture platform. A 3D COMSOL model was built to simulate the mass loading response of increasing concentrations of cells in suspension in the polydimethylsiloxane (PDMS) well in order to predict the characteristics and optimize the design of the SH-SAW biosensor. The simulated relative frequency shift from the two oscillatory circuit systems (one of which functions as control) were found to be concordant to experimental data generated with RAW264.7 macrophage and A549 cancer cells. In addition, results showed that SAW measurements per se did not affect viability of cells. Further, SH-SAW biosensing was applied to A549 cells cultured on a 3D electrospun nanofiber scaffold that generate tumor spheroids (tumoroids) and the results showed the device's ability to detect changes in tumor spheroid growth over the course of eight days. Taken together, these results demonstrate the use of SH-SAW device for detection and quantification of cell growth changes over time in 2D suspension cultures and in 3D cell

  12. Detection of coffee flavour ageing by solid-phase microextraction/surface acoustic wave sensor array technique (SPME/SAW).

    PubMed

    Barié, Nicole; Bücking, Mark; Stahl, Ullrich; Rapp, Michael

    2015-06-01

    The use of polymer coated surface acoustic wave (SAW) sensor arrays is a very promising technique for highly sensitive and selective detection of volatile organic compounds (VOCs). We present new developments to achieve a low cost sensor setup with a sampling method enabling the highly reproducible detection of volatiles even in the ppb range. Since the VOCs of coffee are well known by gas chromatography (GC) research studies, the new sensor array was tested for an easy assessable objective: coffee ageing during storage. As reference method these changes were traced with a standard GC/FID set-up, accompanied by sensory panellists. The evaluation of GC data showed a non-linear characteristic for single compound concentrations as well as for total peak area values, disabling prediction of the coffee age. In contrast, the new SAW sensor array demonstrates a linear dependency, i.e. being capable to show a dependency between volatile concentration and storage time.

  13. Highly sensitive room-temperature surface acoustic wave (SAW) ammonia sensors based on Co₃O₄/SiO₂ composite films.

    PubMed

    Tang, Yong-Liang; Li, Zhi-Jie; Ma, Jin-Yi; Su, Hai-Qiao; Guo, Yuan-Jun; Wang, Lu; Du, Bo; Chen, Jia-Jun; Zhou, Weilie; Yu, Qing-Kai; Zu, Xiao-Tao

    2014-09-15

    Surface acoustic wave (SAW) sensors based on Co3O4/SiO2 composite sensing films for ammonia detection were investigated at room temperature. The Co3O4/SiO2 composite films were deposited onto ST-cut quartz SAW resonators by a sol-gel method. SEM and AFM characterizations showed that the films had porous structures. The existence of SiO2 was found to enhance the ammonia sensing property of the sensor significantly. The sensor based on a Co3O4/SiO2 composite film, with 50% Co3O4 loading, which had the highest RMS value (3.72), showed the best sensing property. It exhibited a positive frequency shift of 3500 Hz to 1 ppm ammonia as well as excellent selectivity, stability and reproducibility at room temperature. Moreover, a 37% decrease in the conductance of the composite film as well as a positive frequency shift of 12,500 Hz were observed when the sensor was exposed to 20 ppm ammonia, indicating the positive frequency shift was derived from the decrease in film conductance.

  14. Evaluation of a gas chromatograph with a novel surface acoustic wave detector (SAW GC) for screening of volatile organic compounds in Hanford waste tank samples

    SciTech Connect

    Lockrem, L.L.

    1998-01-12

    A novel instrument, a gas chromatograph with a Surface Acoustic Wave Detector (SAW GC), was evaluated for the screening of organic compounds in Hanford tank headspace vapors. Calibration data were developed for the most common organic compounds, and the accuracy and precision were measured with a certified standard. The instrument was tested with headspace samples collected from seven Hanford waste tanks.

  15. Etched Cavity SAW (Surface Acoustic Wave) Resonator Elements for Multipole Filter Applications.

    DTIC Science & Technology

    1983-06-01

    frequency response. -26- Device fabrication and test results are discussed in the following section. -27- IV. EXPERIMENTAL RESULTS Initial Test Bar lots were...elements per wavelength, D is the detuning D = 2 r ( 1/p - 1/x ) (2) and G2 = K2 - D2 . Equation (1) has particularly simple forms for the following ...waves [not to be confused and 9(1) from (5) and (6) gives the following wt~h the electroeehanlcal coupling coefficient equations for the

  16. Comparison of fast gas chomatography-surface acoustic wave (FGC-SAW) detection and GC-MS for characterizing blueberry cultivars and maturity.

    PubMed

    Du, Xiaofen; Olmstead, James; Rouseff, Russell

    2012-05-23

    A novel analytical method using fast gas chromatography-surface acoustic wave detection (FGC-SAW) was employed to rapidly characterize blueberry volatile profiles according to genotypes and fruit maturity. Fourteen FGC-SAW peaks were observed and 11 peaks were tentatively identified in the 15 s chromatogram. Peak identifications were confirmed by matching retention index values with similar values from GC-MS analyses of the same samples. Eighty peaks were observed in the 40 min GC-MS analysis of identical samples. Principal component analysis (PCA) score plots of FGC-SAW and GC-MS data both differentiated blueberries according to genotype, maturity stage, and harvest date even though FGC-SAW PCA's used far fewer peak area values. PCA plots clearly separated 'FL02-40', 'Snowchaser', 'Jewel', and 'Primadonna' blueberry cultivars into four quarters using two-dimensional PCA projections. FGC-SAW was also successful in differentiating three berry maturity stages in PCA score plots for both 'Jewel' and 'Primadonna' cultivars. FGC-SAW is an effective technique for rapid analysis of major blueberry volatiles, but could not determine many mid- and low-level volatiles as they were often coeluted with higher concentration volatiles.

  17. Using Nano-mechanics and Surface Acoustic Wave (SAW) for Disease Monitoring and Diagnostics at a Cellular Level in Red Blood Cells

    NASA Astrophysics Data System (ADS)

    Sivanantha, Ninnuja; Ma, Charles; Collins, David J.; Sesen, Muhsincan; Brenker, Jason; Coppel, Ross L.; Neild, Adrian; Alan, Tuncay

    A popular approach to monitoring diseases and their diagnosis is through biological, pathological or immunological characterization. However, at a cellular level progression of certain diseases manifests itself through mechanical effects as well. Here, we present a method which exploits localised flow; surface acoustic wave (SAW) induced acoustic streaming in a 9 μL droplet to characterize the adhesive properties of red blood cells (healthy, gluteraldehyde treated and malaria infected) in approximately 50 seconds. Our results show a 79% difference in cell mobilization between healthy malaria infected RBCs (and a 39% difference between healthy and treated ones), indicating that the method can serve as a platform for rapid clinical diagnosis; where separation of two or more different cell populations in a mixed solution is desirable. It can also act as a key biomarker for monitoring some diseases offering quantitative measures of disease progression and response to therapy.

  18. Surface acoustic wave microfluidics.

    PubMed

    Ding, Xiaoyun; Li, Peng; Lin, Sz-Chin Steven; Stratton, Zackary S; Nama, Nitesh; Guo, Feng; Slotcavage, Daniel; Mao, Xiaole; Shi, Jinjie; Costanzo, Francesco; Huang, Tony Jun

    2013-09-21

    The recent introduction of surface acoustic wave (SAW) technology onto lab-on-a-chip platforms has opened a new frontier in microfluidics. The advantages provided by such SAW microfluidics are numerous: simple fabrication, high biocompatibility, fast fluid actuation, versatility, compact and inexpensive devices and accessories, contact-free particle manipulation, and compatibility with other microfluidic components. We believe that these advantages enable SAW microfluidics to play a significant role in a variety of applications in biology, chemistry, engineering and medicine. In this review article, we discuss the theory underpinning SAWs and their interactions with particles and the contacting fluids in which they are suspended. We then review the SAW-enabled microfluidic devices demonstrated to date, starting with devices that accomplish fluid mixing and transport through the use of travelling SAW; we follow that by reviewing the more recent innovations achieved with standing SAW that enable such actions as particle/cell focusing, sorting and patterning. Finally, we look forward and appraise where the discipline of SAW microfluidics could go next.

  19. Surface acoustic wave microfluidics

    PubMed Central

    Ding, Xiaoyun; Li, Peng; Lin, Sz-Chin Steven; Stratton, Zackary S.; Nama, Nitesh; Guo, Feng; Slotcavage, Daniel; Mao, Xiaole; Shi, Jinjie; Costanzo, Francesco; Huang, Tony Jun

    2014-01-01

    The recent introduction of surface acoustic wave (SAW) technology onto lab-on-a-chip platforms has opened a new frontier in microfluidics. The advantages provided by such SAW microfluidics are numerous: simple fabrication, high biocompatibility, fast fluid actuation, versatility, compact and inexpensive devices and accessories, contact-free particle manipulation, and compatibility with other microfluidic components. We believe that these advantages enable SAW microfluidics to play a significant role in a variety of applications in biology, chemistry, engineering, and medicine. In this review article, we discuss the theory underpinning SAWs and their interactions with particles and the contacting fluids in which they are suspended. We then review the SAW-enabled microfluidic devices demonstrated to date, starting with devices that accomplish fluid mixing and transport through the use of travelling SAW; we follow that by reviewing the more recent innovations achieved with standing SAW that enable such actions as particle/cell focusing, sorting, and patterning. Finally, we look forward and appraise where the discipline of SAW microfluidics could go next. PMID:23900527

  20. Investigation of crossed SAW fields by scanning acoustic force microscopy.

    PubMed

    Behme, G; Hesjedal, T

    2001-07-01

    We used multimode scanning acoustic force microscopy (SAFM) for studying noncollinearly propagating Rayleigh and Love wave fields. By analyzing torsion and bending movement of SAFM cantilever, normal and in-plane wave oscillation components are accessible. The SAFM principle is the down-conversion of surface oscillations into cantilever vibrations caused by the nonlinearity of the tip-sample interaction. Through mixing of complementary oscillation components, phase velocities of crossed Rayleigh waves on GaAs and crossed Rayleigh and Love waves on the layered system SiO2/ST-cut quartz were obtained simultaneously. Now, it is possible to investigate elastic properties of submicron areas through multimode SAFM measurements. Finally, we present mixing experiments of four SAWs on GaAs and discuss the various influences on the measured SAFM amplitude and phase contrast.

  1. Mass flux response comparisons of a 200-MHz surface acoustic wave (SAW) resonator microbalance to a 15-MHz thermoelectric quartz crystal microbalance (TQCM) in a high-vacuum environment

    NASA Astrophysics Data System (ADS)

    Wallace, Donald A.; Bowers, William D.

    1994-10-01

    Using a 200 MHz Surface Acoustic Wave (SAW) resonator device as a high-vacuum molecular deposition microbalance, similar to a bulk quartz crystal microbalance (QCM), and an often-used 15 MHz thermoelectric QCM (TQCM), a comparison of various parameters was made during a high-vacuum outgassing experiment. The source of molecular outgassing was a bright aluminum foil which was cooled to liquid nitrogen temperature and alternately, to ambient temperature. The two sensors, the SAW QCM and the TQCM were placed next to each other and viewed only the aluminum foil. In this high-vacuum environment, a comparison between various parameters, i.e., mass sensitivity, long term drift rate, stability, thermal effects and dynamic range of the SAW and the TQCM, was obtained.

  2. SAW devices based on novel surface wave excitations

    NASA Astrophysics Data System (ADS)

    Therrien, Joel; Dai, Lian

    2015-03-01

    Surface Acoustic Wave (SAW) devices have applications in radio frequency and microwave filtering as well as highly sensitive sensors. Current SAW design employs the use of an array of electrode pairs, referred to as Inter-Digitated Transducers (IDTs) for creating and receiving surface waves on piezoelectric substrates. The pitch of the electrode pairs along with the properties of the substrate determine the operating frequency. The number of electrode pairs determine the bandwidth of the emitted waves. We will present a novel configuration that eliminates the need for the IDTs and replaces with with a single circular electrode located inside a larger ground ring. This configuration induces drumhead modes. We will show that the resonant frequencies follow the zeros of Bessel functions of the first kind. Applications in RF filtering and mass sensing will be presented.

  3. Surface acoustic wave oxygen sensor

    NASA Technical Reports Server (NTRS)

    Collman, James P.; Oglesby, Donald M.; Upchurch, Billy T.; Leighty, Bradley D.; Zhang, Xumu; Herrmann, Paul C.

    1994-01-01

    A surface acoustic wave (SAW) device that responds to oxygen pressure was developed by coating a 158 MHz quartz surface acoustic wave (SAW) device with an oxygen binding agent. Two types of coatings were used. One type was prepared by dissolving an oxygen binding agent in a toluene solution of a copolymer containing the axial ligand. A second type was prepared with an oxygen binding porphyrin solution containing excess axial ligand without a polymer matrix. In the polymer based coatings, the copolymer served to provide the axial ligand to the oxygen binding agent and as a coating matrix on the surface of the SAW device. The oxygen sensing SAW device has been shown to bind oxygen following a Langmuir isotherm and may be used to measure the equilibrium constant of the oxygen binding compound in the coating matrix.

  4. Absorption of surface acoustic waves by graphene

    NASA Astrophysics Data System (ADS)

    Zhang, S. H.; Xu, W.

    2011-06-01

    We present a theoretical study on interactions of electrons in graphene with surface acoustic waves (SAWs). We find that owing to momentum and energy conservation laws, the electronic transition accompanied by the SAW absorption cannot be achieved via inter-band transition channels in graphene. For graphene, strong absorption of SAWs can be observed in a wide frequency range up to terahertz at room temperature. The intensity of SAW absorption by graphene depends strongly on temperature and can be adjusted by changing the carrier density. This study is relevant to the exploration of the acoustic properties of graphene and to the application of graphene as frequency-tunable SAW devices.

  5. Swimming Using Surface Acoustic Waves

    PubMed Central

    Bourquin, Yannyk; Cooper, Jonathan M.

    2013-01-01

    Microactuation of free standing objects in fluids is currently dominated by the rotary propeller, giving rise to a range of potential applications in the military, aeronautic and biomedical fields. Previously, surface acoustic waves (SAWs) have been shown to be of increasing interest in the field of microfluidics, where the refraction of a SAW into a drop of fluid creates a convective flow, a phenomenon generally known as SAW streaming. We now show how SAWs, generated at microelectronic devices, can be used as an efficient method of propulsion actuated by localised fluid streaming. The direction of the force arising from such streaming is optimal when the devices are maintained at the Rayleigh angle. The technique provides propulsion without any moving parts, and, due to the inherent design of the SAW transducer, enables simple control of the direction of travel. PMID:23431358

  6. Swimming using surface acoustic waves.

    PubMed

    Bourquin, Yannyk; Cooper, Jonathan M

    2013-01-01

    Microactuation of free standing objects in fluids is currently dominated by the rotary propeller, giving rise to a range of potential applications in the military, aeronautic and biomedical fields. Previously, surface acoustic waves (SAWs) have been shown to be of increasing interest in the field of microfluidics, where the refraction of a SAW into a drop of fluid creates a convective flow, a phenomenon generally known as SAW streaming. We now show how SAWs, generated at microelectronic devices, can be used as an efficient method of propulsion actuated by localised fluid streaming. The direction of the force arising from such streaming is optimal when the devices are maintained at the Rayleigh angle. The technique provides propulsion without any moving parts, and, due to the inherent design of the SAW transducer, enables simple control of the direction of travel.

  7. Surface acoustic wave propagation in graphene

    NASA Astrophysics Data System (ADS)

    Thalmeier, Peter; Dóra, Balázs; Ziegler, Klaus

    2010-01-01

    Surface acoustic wave (SAW) propagation is a powerful method to investigate two-dimensional (2D) electron systems. We show how SAW observables are influenced by coupling to the 2D massless Dirac electrons of graphene and argue that Landau oscillations in SAW propagation can be observed as function of gate voltage for constant field. Contrary to other transport measurements, the zero-field SAW propagation gives the wave-vector dependence of graphene conductivity for small wave numbers. We predict a crossover from Schrödinger to Dirac-like behavior as a function of gate voltage, with no attenuation in the latter for clean samples.

  8. Surface acoustic wave propagation in graphene film

    SciTech Connect

    Roshchupkin, Dmitry Plotitcyna, Olga; Matveev, Viktor; Kononenko, Oleg; Emelin, Evgenii; Irzhak, Dmitry; Ortega, Luc; Zizak, Ivo; Erko, Alexei; Tynyshtykbayev, Kurbangali; Insepov, Zinetula

    2015-09-14

    Surface acoustic wave (SAW) propagation in a graphene film on the surface of piezoelectric crystals was studied at the BESSY II synchrotron radiation source. Talbot effect enabled the visualization of the SAW propagation on the crystal surface with the graphene film in a real time mode, and high-resolution x-ray diffraction permitted the determination of the SAW amplitude in the graphene/piezoelectric crystal system. The influence of the SAW on the electrical properties of the graphene film was examined. It was shown that the changing of the SAW amplitude enables controlling the magnitude and direction of current in graphene film on the surface of piezoelectric crystals.

  9. Surface acoustic wave propagation in graphene film

    NASA Astrophysics Data System (ADS)

    Roshchupkin, Dmitry; Ortega, Luc; Zizak, Ivo; Plotitcyna, Olga; Matveev, Viktor; Kononenko, Oleg; Emelin, Evgenii; Erko, Alexei; Tynyshtykbayev, Kurbangali; Irzhak, Dmitry; Insepov, Zinetula

    2015-09-01

    Surface acoustic wave (SAW) propagation in a graphene film on the surface of piezoelectric crystals was studied at the BESSY II synchrotron radiation source. Talbot effect enabled the visualization of the SAW propagation on the crystal surface with the graphene film in a real time mode, and high-resolution x-ray diffraction permitted the determination of the SAW amplitude in the graphene/piezoelectric crystal system. The influence of the SAW on the electrical properties of the graphene film was examined. It was shown that the changing of the SAW amplitude enables controlling the magnitude and direction of current in graphene film on the surface of piezoelectric crystals.

  10. Surface acoustic wave stabilized oscillators

    NASA Technical Reports Server (NTRS)

    Parker, T. E.

    1978-01-01

    A number of 401.2 MHz surface acoustic wave (SAW) controlled oscillators were built and tested. The performance of these oscillators was evaluated for possible use as stable oscillators in communication systems. A short term frequency stability of better than 1 x 10 to the minus 9th power for one second was measured for the SAW oscillators. Long term frequency drift was measured and was found to be dependent on SAW design and packaging. Drift rates ranging from 15 ppm in twenty weeks to 2.5 ppm in twenty weeks were observed. Some further improvement was required. The temperature dependence of the saw oscillators was evaluated and it was concluded that some form of temperature compensation will be necessary to meet the requirements of some communication systems.

  11. Use of multiple acoustic reflections to enhance SAW UV photo-detector sensitivity

    NASA Astrophysics Data System (ADS)

    Karapetyan, G. Y.; Kaydashev, V. E.; Zhilin, D. A.; Minasyan, T. A.; Abdulvakhidov, K. G.; Kaidashev, E. M.

    2017-03-01

    A new approach to enhance the sensitivity of existing SAW UV-visible photo-detectors based on the monitoring of the multiple reflections of the acoustic waves in the Fourier transform of the frequency response (S21) is demonstrated. By using this concept, it is possible to monitor the UV-visible light in a wide intensity range from very high to ultralow. We present a strategy to obtain an ultrafast SAW UV photo-detector with millisecond response by tuning the deposition conditions of the ZnO film and using the multiple-reflections concept.

  12. Gas sensing with surface acoustic wave devices

    NASA Astrophysics Data System (ADS)

    Martin, S. J.; Schweizer, K. S.; Ricco, A. J.; Zipperian, T. E.

    1985-03-01

    The use of a ZnO-on-Si surface acoustic wave (SAW) resonator as a gas sensor is discussed. In particular, the sensitivity of the device to organic vapors is examined. The planar nature of the SAW device, in which the acoustic energy is confined to within roughly one acoustic wavelength of the surface, makes the device extremely sensitive to surface perturbations. This characteristic has been exploited in the construction of SAW gas sensors in which the surface wave propagation characteristics are altered by species adsorbed from the ambient gas. The porous nature of the sputtered ZnO film, in conjunction with the microbalance capability of the SAW device, gives the sensor the ability to distinguish molecules on the basis of both size and mass.

  13. Ring waveguide resonator on surface acoustic waves

    NASA Astrophysics Data System (ADS)

    Biryukov, S. V.; Martin, G.; Weihnacht, M.

    2007-04-01

    A simple regular electrode structure for surface acoustic wave (SAW) devices is proposed. The structure consists of an interdigital transducer in the form of a ring placed on the Z cut of a hexagonal piezoelectric crystal. Finite thickness electrodes produce the known slowing effect for a SAW in comparison with this SAW on a free surface. The closed "slow" electrode region with the "fast" surrounding region forms an open waveguide resonator structure with the acoustic field concentrated in the electrode region. If the radius of the structure is large enough for a given wavelength, an acceptable level of radiation losses can be reached. The electrical admittance of such resonator does not have sidelobes.

  14. Probing Acoustic Nonlinearity by Mixing Surface Acoustic Waves

    SciTech Connect

    Hurley, David Howard; Telschow, Kenneth Louis

    2000-07-01

    Measurement methods aimed at determining material properties through nonlinear wave propagation are sensitive to artifacts caused by background nonlinearities inherent in the ultrasonic generation and detection methods. The focus of this paper is to describe our investigation of nonlinear mixing of surface acoustic waves (SAWs) as a means to decrease sensitivity to background nonlinearity and increase spatial sensitivity to acoustic nonlinearity induced by material microstructure.

  15. Surface Acoustic Wave Tag-Based Coherence Multiplexing

    NASA Technical Reports Server (NTRS)

    Youngquist, Robert C. (Inventor); Malocha, Donald (Inventor); Saldanha, Nancy (Inventor)

    2016-01-01

    A surface acoustic wave (SAW)-based coherence multiplexing system includes SAW tags each including a SAW transducer, a first SAW reflector positioned a first distance from the SAW transducer and a second SAW reflector positioned a second distance from the SAW transducer. A transceiver including a wireless transmitter has a signal source providing a source signal and circuitry for transmitting interrogation pulses including a first and a second interrogation pulse toward the SAW tags, and a wireless receiver for receiving and processing response signals from the SAW tags. The receiver receives scrambled signals including a convolution of the wideband interrogation pulses with response signals from the SAW tags and includes a computing device which implements an algorithm that correlates the interrogation pulses or the source signal before transmitting against the scrambled signals to generate tag responses for each of the SAW tags.

  16. Applications of surface acoustic and shallow bulk acoustic wave devices

    NASA Astrophysics Data System (ADS)

    Campbell, Colin K.

    1989-10-01

    Surface acoustic wave (SAW) device coverage includes delay lines and filters operating at selected frequencies in the range from about 10 MHz to 11 GHz; modeling with single-crystal piezoelectrics and layered structures; resonators and low-loss filters; comb filters and multiplexers; antenna duplexers; harmonic devices; chirp filters for pulse compression; coding with fixed and programmable transversal filters; Barker and quadraphase coding; adaptive filters; acoustic and acoustoelectric convolvers and correlators for radar, spread spectrum, and packet radio; acoustooptic processors for Bragg modulation and spectrum analysis; real-time Fourier-transform and cepstrum processors for radar and sonar; compressive receivers; Nyquist filters for microwave digital radio; clock-recovery filters for fiber communications; fixed-, tunable-, and multimode oscillators and frequency synthesizers; acoustic charge transport; and other SAW devices for signal processing on gallium arsenide. Shallow bulk acoustic wave device applications include gigahertz delay lines, surface-transverse-wave resonators employing energy-trapping gratings, and oscillators with enhanced performance and capability.

  17. Nanoliter-droplet acoustic streaming via ultra high frequency surface acoustic waves.

    PubMed

    Shilton, Richie J; Travagliati, Marco; Beltram, Fabio; Cecchini, Marco

    2014-08-06

    The relevant length scales in sub-nanometer amplitude surface acoustic wave-driven acoustic streaming are demonstrated. We demonstrate the absence of any physical limitations preventing the downscaling of SAW-driven internal streaming to nanoliter microreactors and beyond by extending SAW microfluidics up to operating frequencies in the GHz range. This method is applied to nanoliter scale fluid mixing.

  18. Wireless Multiplexed Surface Acoustic Wave Sensors Project

    NASA Technical Reports Server (NTRS)

    Youngquist, Robert C.

    2014-01-01

    Wireless Surface Acoustic Wave (SAW) Sensor is a new technology for obtaining multiple, real-time measurements under extreme environmental conditions. This project plans to develop a wireless multiplexed sensor system that uses SAW sensors, with no batteries or semiconductors, that are passive and rugged, can operate down to cryogenic temperatures and up to hundreds of degrees C, and can be used to sense a wide variety of parameters over reasonable distances (meters).

  19. Surface Acoustic Wave Atomizer and Electrostatic Deposition

    NASA Astrophysics Data System (ADS)

    Yamagata, Yutaka

    A new methodology for fabricating thin film or micro patters of organic/bio material using surface acoustic wave (SAW) atomizer and electrostatic deposition is proposed and characteristics of atomization techniques are discussed in terms of drop size and atomization speed. Various types of SAW atomizer are compared with electrospray and conventional ultrasonic atomizers. It has been proved that SAW atomizers generate drops as small as electrospray and have very fast atomization speed. This technique is applied to fabrication of micro patterns of proteins. According to the result of immunoassay, the specific activity of immunoglobulin was preserved after deposition process.

  20. Surface acoustic wave atomizer and electrostatic deposition.

    PubMed

    Yamagata, Yutaka

    2010-01-01

    A new methodology for fabricating thin film or micro patters of organic/bio material using surface acoustic wave (SAW) atomizer and electrostatic deposition is proposed and characteristics of atomization techniques are discussed in terms of drop size and atomization speed. Various types of SAW atomizer are compared with electrospray and conventional ultrasonic atomizers. It has been proved that SAW atomizers generate drops as small as electrospray and have very fast atomization speed. This technique is applied to fabrication of micro patterns of proteins. According to the result of immunoassay, the specific activity of immunoglobulin was preserved after deposition process.

  1. Surface acoustic wave frequency comb

    NASA Astrophysics Data System (ADS)

    Matsko, A. B.; Savchenkov, A. A.; Ilchenko, V. S.; Seidel, D.; Maleki, L.

    2012-02-01

    We investigate opto-mechanical oscillation (OMO) and subsequent generation of acoustic wave frequency combs in monolithic crystalline whispering gallery mode (WGM) resonators. The OMO is observed in resonators made of electro-optic (lithium tantalate), non-electro-optic birefringent (magnesium fluoride), and non-birefringent (calcium fluoride) materials. The phenomenon manifests itself as generation of optical harmonics separated by the eigenfrequency of a surface acoustic wave (SAW) mechanical mode of the same WGM resonator. We show that the light escaping the resonator and demodulated on a fast photodiode produces a spectrally pure radio frequency (RF) signal. For instance, we demonstrate generation of 200 MHz signals with instantaneous linewidth of 0.2 Hz.

  2. Accurate measurements of the acoustical physical constants of synthetic alpha-quartz for SAW devices.

    PubMed

    Kushibiki, Juin-ichi; Takanaga, Izumi; Nishiyama, Shouichi

    2002-01-01

    Accurate measurements of the acoustical physical constants (elastic constants, piezoelectric constants, dielectric constants, and density) of commercially available and widely used surface acoustic wave (SAW)-grade synthetic a-quartz are reported. The propagation directions and modes of bulk waves optimal for accurately determining the constants were selected through numerical calculations, and three principal X-, Y-, and Z-cut specimens and several rotated Y-cut specimens were prepared from a single crystal ingot to determine the constants and to confirm their accuracy. All of the constants were determined through highly accurate measurements of the longitudinal velocities, shear velocities, dielectric constants, and density. The velocity values measured for the specimens that were not used to determine the constants agreed well with those calculated from the determined constants, within a difference of +/- 0.20 m/s (+/- 0.004%).

  3. Thin Superconducting Film Characterization by Surface Acoustic Waves.

    DTIC Science & Technology

    2014-09-26

    NUMBER 2. GOVT ACCESSION NO. 3 RECIPIENT’S CA ALOG NUMBER ~~AFOSR TR -0 8 4. TITLE (and Subtitle) 5 TYPE OF REPORT & PERIOD COVERED Thin Superconducting ...thin film superconductor surface acoustic waves I SAW electron phonon interaction superconducting energy gap electron mean free path vortex...electrical resistivity and the attenuation of surface ,e J -acoustic waves (SAW) were measured in the superconducting state of a L granular lead film

  4. Acoustic wave based MEMS devices for biosensing applications.

    PubMed

    Voiculescu, Ioana; Nordin, Anis Nurashikin

    2012-03-15

    This paper presents a review of acoustic-wave based MEMS devices that offer a promising technology platform for the development of sensitive, portable, real-time biosensors. MEMS fabrication of acoustic wave based biosensors enables device miniaturization, power consumption reduction and integration with electronic circuits. For biological applications, the biosensors are integrated in a microfluidic system and the sensing area is coated with a biospecific layer. When a bioanalyte interacts with the sensing layer, mass and viscosity variations of the biospecific layer can be detected by monitoring changes in the acoustic wave properties such as velocity, attenuation, resonant frequency and delay time. Few types of acoustic wave devices could be integrated in microfluidic systems without significant degradation of the quality factor. The acoustic wave based MEMS devices reported in the literature as biosensors and presented in this review are film bulk acoustic wave resonators (FBAR), surface acoustic waves (SAW) resonators and SAW delay lines. Different approaches to the realization of FBARs, SAW resonators and SAW delay lines for various biochemical applications are presented. Methods of integration of the acoustic wave MEMS devices in the microfluidic systems and functionalization strategies will be also discussed.

  5. Modeling of a Surface Acoustic Wave Strain Sensor

    NASA Technical Reports Server (NTRS)

    Wilson, W. C.; Atkinson, Gary M.

    2010-01-01

    NASA Langley Research Center is investigating Surface Acoustic Wave (SAW) sensor technology for harsh environments aimed at aerospace applications. To aid in development of sensors a model of a SAW strain sensor has been developed. The new model extends the modified matrix method to include the response of Orthogonal Frequency Coded (OFC) reflectors and the response of SAW devices to strain. These results show that the model accurately captures the strain response of a SAW sensor on a Langasite substrate. The results of the model of a SAW Strain Sensor on Langasite are presented

  6. Comparison of Transmission Line Methods for Surface Acoustic Wave Modeling

    NASA Technical Reports Server (NTRS)

    Wilson, William; Atkinson, Gary

    2009-01-01

    Surface Acoustic Wave (SAW) technology is low cost, rugged, lightweight, extremely low power and can be used to develop passive wireless sensors. For these reasons, NASA is investigating the use of SAW technology for Integrated Vehicle Health Monitoring (IVHM) of aerospace structures. To facilitate rapid prototyping of passive SAW sensors for aerospace applications, SAW models have been developed. This paper reports on the comparison of three methods of modeling SAWs. The three models are the Impulse Response Method (a first order model), and two second order matrix methods; the conventional matrix approach, and a modified matrix approach that is extended to include internal finger reflections. The second order models are based upon matrices that were originally developed for analyzing microwave circuits using transmission line theory. Results from the models are presented with measured data from devices. Keywords: Surface Acoustic Wave, SAW, transmission line models, Impulse Response Method.

  7. Optimizing surface acoustic wave sensors for trace chemical detection

    SciTech Connect

    Frye, G.C.; Kottenstette, R.J.; Heller, E.J.

    1997-06-01

    This paper describes several recent advances for fabricating coated surface acoustic wave (SAW) sensors for applications requiring trace chemical detection. Specifically, we have demonstrated that high surface area microporous oxides can provide 100-fold improvements in SAW sensor responses compared with more typical polymeric coatings. In addition, we fabricated GaAs SAW devices with frequencies up to 500 MHz to provide greater sensitivity and an ideal substrate for integration with high-frequency electronics.

  8. Acoustic Wave Filter Technology - A Review.

    PubMed

    Ruppel, Clemens

    2017-04-04

    Today, acoustic filters are the filter technology to meet the requirements with respect to performance dictated by the cellular phone standards and their form factor. Around 2 billion cellular phones are sold every year, and smart phones are of a very high percentage of approximately two thirds. Smart phones require a very high number of filter functions ranging from the low double-digit range up to almost triple digit numbers in the near future. In the frequency range up to 1 GHz surface acoustic wave (SAW) filters are almost exclusively employed, while in the higher frequency range bulk acoustic wave (BAW) and SAW filters are competing for their shares. Prerequisites for the success of acoustic filters were the availability of high quality substrates, advanced and highly reproducible fabrication technologies, optimum filter techniques, precise simulation software, and advanced design tools that allow the fast and efficient design according to customer specifications. The paper will try to focus on innovations leading to high volume applications of intermediate frequency (IF) and radio frequency (RF) acoustic filters, e.g., TV IF filters, IF filters for cellular phones, and SAW/BAW RF filters for the RF front-end of cellular phones.

  9. Surface acoustic wave biosensors: a review.

    PubMed

    Länge, Kerstin; Rapp, Bastian E; Rapp, Michael

    2008-07-01

    This review presents an overview of 20 years of worldwide development in the field of biosensors based on special types of surface acoustic wave (SAW) devices that permit the highly sensitive detection of biorelevant molecules in liquid media (such as water or aqueous buffer solutions). 1987 saw the first approaches, which used either horizontally polarized shear waves (HPSW) in a delay line configuration on lithium tantalate (LiTaO(3)) substrates or SAW resonator structures on quartz or LiTaO(3) with periodic mass gratings. The latter are termed "surface transverse waves" (STW), and they have comparatively low attenuation values when operated in liquids. Later Love wave devices were developed, which used a film resonance effect to significantly reduce attenuation. All of these sensor approaches were accompanied by the development of appropriate sensing films. First attempts used simple layers of adsorbed antibodies. Later approaches used various types of covalently bound layers, for example those utilizing intermediate hydrogel layers. Recent approaches involve SAW biosensor devices inserted into compact systems with integrated fluidics for sample handling. To achieve this, the SAW biosensors can be embedded into micromachined polymer housings. Combining these two features will extend the system to create versatile biosensor arrays for generic lab use or for diagnostic purposes.

  10. Laboratory observations of self-excited dust acoustic shock waves

    NASA Astrophysics Data System (ADS)

    Merlino, Robert L.; Heinrich, Jonathon R.; Kim, Su-Hyun

    2009-11-01

    Dust acoustic waves have been discussed in connection with dust density structures in Saturn's rings and the Earth's mesosphere, and as a possible mechanism for triggering condensation of small grains in dust molecular clouds. Dust acoustic waves are a ubiquitous occurrence in laboratory dusty plasmas formed in glow discharges. We report observations of repeated, self-excited dust acoustic shock waves in a dc glow discharge dusty plasma using high-speed video imaging. Two major observations will be presented: (1) The self-steepening of a nonlinear dust acoustic wave into a saw-tooth wave with sharp gradient in dust density, very similar to those found in numerical solutions [1] of the fully nonlinear fluid equations for nondispersive dust acoustic waves, and (2) the collision and confluence of two dust acoustic shock waves. [4pt] [1] B. Eliasson and P. K. Shukla, Phys. Rev. E 69, 067401 (2004).

  11. Active micromixer using surface acoustic wave streaming

    SciTech Connect

    Branch; Darren W. , Meyer; Grant D. , Craighead; Harold G.

    2011-05-17

    An active micromixer uses a surface acoustic wave, preferably a Rayleigh wave, propagating on a piezoelectric substrate to induce acoustic streaming in a fluid in a microfluidic channel. The surface acoustic wave can be generated by applying an RF excitation signal to at least one interdigital transducer on the piezoelectric substrate. The active micromixer can rapidly mix quiescent fluids or laminar streams in low Reynolds number flows. The active micromixer has no moving parts (other than the SAW transducer) and is, therefore, more reliable, less damaging to sensitive fluids, and less susceptible to fouling and channel clogging than other types of active and passive micromixers. The active micromixer is adaptable to a wide range of geometries, can be easily fabricated, and can be integrated in a microfluidic system, reducing dead volume. Finally, the active micromixer has on-demand on/off mixing capability and can be operated at low power.

  12. Surface acoustic wave microsensors and applications

    NASA Astrophysics Data System (ADS)

    Galipeau, David W.; Story, Patrick R.; Vetelino, Kevin A.; Mileham, Russell D.

    1997-12-01

    Surface acoustic wave (SAW) devices have been studied for the last twenty years as highly sensitive yet relatively inexpensive microsensors for applications ranging from temperature and stress to gas and biological sensing. This wide range of applications is due to the SAW microsensors' high sensitivity to several physical parameters including mass, temperature, stress, and conductivity. Their low cost results from the use of standard batch microelectronic fabrication techniques for their manufacture. In this paper several chemical sensing applications for SAW devices are described. These include: gas detection; thin-film polymer characterization; dew-point measurements; surface energy measurements; and as a method to measure surface cleanliness. Experimental results are presented along with comparisons to other measurement techniques.

  13. Surface acoustic wave microsensors and applications

    NASA Astrophysics Data System (ADS)

    Galipeau, David W.; Story, Patrick R.; Vetelino, Kevin A.; Mileham, R. D.

    1997-06-01

    Surface acoustic wave (SAW) devices have been studied for the last twenty years as highly sensitive yet relatively inexpensive microsensors for applications ranging from gas and biological sensing to thin film and surface characterization. This wide range of applications is due to SAW microsensors high sensitivity to several physical parameters including mass, conductivity, permittivity, stress, temperature and electric fields. Their low cost results from the use of standard batch microelectronic fabrication techniques for their manufacture. In this work several SAW sensing applications are described. These include: gas detection; thin film polymer characterization; dew-point measurements; surface energy measurements; and as a method to measure surface cleanliness. Experimental results are presented along with comparisons to other measurement techniques.

  14. Attenuation of 7 GHz surface acoustic waves on silicon

    NASA Astrophysics Data System (ADS)

    Li, Dongyao; Cahill, David G.

    2016-09-01

    We measured the attenuation of GHz frequency surface acoustic waves (SAWs) on the Si (001) surface using an optical pump-probe technique at temperatures between 300 and 600 K. SAWs are generated and detected by a 700 nm Al grating fabricated by nanoimprint lithography. The grating for SAW generation is separated from the grating for SAW detection by ≈150 μ m . The amplitude of SAWs is attenuated by coupling to bulk waves created by the Al grating, diffraction due to the finite size of the source, and the intrinsic relaxational Akhiezer damping of elastic waves in Si. Thermal phonon relaxation time and Grüneisen parameters are fitted using temperature-dependent measurement. The f Q product of a hypothetical micromechanical oscillator limited by Akhiezer damping at this frequency is ˜3 ×1013 Hz.

  15. Individually Identifiable Surface Acoustic Wave Sensors, Tags and Systems

    NASA Technical Reports Server (NTRS)

    Hines, Jacqueline H. (Inventor); Solie, Leland P. (Inventor); Tucker, Dana Y. G. (Inventor); Hines, Andrew T. (Inventor)

    2017-01-01

    A surface-launched acoustic wave sensor tag system for remotely sensing and/or providing identification information using sets of surface acoustic wave (SAW) sensor tag devices is characterized by acoustic wave device embodiments that include coding and other diversity techniques to produce groups of sensors that interact minimally, reducing or alleviating code collision problems typical of prior art coded SAW sensors and tags, and specific device embodiments of said coded SAW sensor tags and systems. These sensor/tag devices operate in a system which consists of one or more uniquely identifiable sensor/tag devices and a wireless interrogator. The sensor device incorporates an antenna for receiving incident RF energy and re-radiating the tag identification information and the sensor measured parameter(s). Since there is no power source in or connected to the sensor, it is a passive sensor. The device is wirelessly interrogated by the interrogator.

  16. FROM THE CURRENT LITERATURE: Laser excitation of surface acoustic waves: a new direction in opto-acoustic spectroscopy of a solid

    NASA Astrophysics Data System (ADS)

    Karabutov, Aleksander A.

    1985-11-01

    Studies in thermo-optic excitation of surface acoustic waves are reviewed. The excitation of periodic and pulse signals is discussed, using nonmoving and moving beams. Most attention is paid to application of this effect for purposes of opto-acoustic spectroscopy of a solid. The possibilities and promises of using opto-acoustic spectroscopy (OAS) employing surface acoustic waves (SAW) are analyzed

  17. Rapid SAW Sensor Development Tools

    NASA Technical Reports Server (NTRS)

    Wilson, William C.; Atkinson, Gary M.

    2007-01-01

    The lack of integrated design tools for Surface Acoustic Wave (SAW) devices has led us to develop tools for the design, modeling, analysis, and automatic layout generation of SAW devices. These tools enable rapid development of wireless SAW sensors. The tools developed have been designed to integrate into existing Electronic Design Automation (EDA) tools to take advantage of existing 3D modeling, and Finite Element Analysis (FEA). This paper presents the SAW design, modeling, analysis, and automated layout generation tools.

  18. Droplet actuation by surface acoustic waves: an interplay between acoustic streaming and radiation pressure

    NASA Astrophysics Data System (ADS)

    Brunet, Philippe; Baudoin, Michael; Matar, Olivier Bou; Zoueshtiagh, Farzam

    2010-11-01

    Surface acoustic waves (SAW) are known to be a versatile technique for the actuation of sessile drops. Droplet displacement, internal mixing or drop splitting, are amongst the elementary operations that SAW can achieve, which are useful on lab-on-chip microfluidics benches. On the purpose to understand the underlying physical mechanisms involved during these operations, we study experimentally the droplet dynamics varying different physical parameters. Here in particular, the influence of liquid viscosity and acoustic frequency is investigated: it is indeed predicted that both quantities should play a role in the acoustic-hydrodynamic coupling involved in the dynamics. The key point is to compare the relative magnitude of the attenuation length, i.e. the scale within which the acoustic wave decays in the fluid, and the size of the drop. This relative magnitude governs the relative importance of acoustic streaming and acoustic radiation pressure, which are both involved in the droplet dynamics.

  19. Scanning Michelson interferometer for imaging surface acoustic wave fields.

    PubMed

    Knuuttila, J V; Tikka, P T; Salomaa, M M

    2000-05-01

    A scanning homodyne Michelson interferometer is constructed for two-dimensional imaging of high-frequency surface acoustic wave (SAW) fields in SAW devices. The interferometer possesses a sensitivity of ~10(-5)nm/ radicalHz , and it is capable of directly measuring SAW's with frequencies ranging from 0.5 MHz up to 1 GHz. The fast scheme used for locating the optimum operation point of the interferometer facilitates high measuring speeds, up to 50,000 points/h. The measured field image has a lateral resolution of better than 1 mu;m . The fully optical noninvasive scanning system can be applied to SAW device development and research, providing information on acoustic wave distribution that cannot be obtained by merely electrical measurements.

  20. Evaluation of Relative Sensitivity of SAW and Flexural Plate Wave Devices for Atmospheric Sensing

    NASA Technical Reports Server (NTRS)

    White, Richard M.; Black, Justin; Chen, Bryan

    1998-01-01

    The objective of this project is to evaluate the suitability of the ultrasonic flexural plate wave (FPW) device as the detector in a gas chromatograph (GC). Of particular interest is the detection of nitrous oxide (N2O). From experimental results we conclude analyte detection is achieved through two mechanisms: changes in gas density, and mass loading of the device membrane due to the sorption of gas molecules. Reducing the dead volume of the FPW chamber increased the FPW response. A comparison of the FPW response to that of the surface acoustic wave (SAW) detector provided with the GC (made by MSI, Microsensor Technologies, Inc.), shows that for unseparated N2O in N2, the FPW exhibits a sensitivity that is at least 550 times greater than that of the SAW device. A Porapak Q column was found to separate N2O from its carrier gas, N2 or He. With the Porapak Q column, a coated FPW detected 1 ppm N2O in N2 or He, with a response magnitude of 7 Hz. A coated SAW exhibited a response of 25 Hz to pure N2O. The minimal detectable N2O concentrations of the sensors were not evaluated.

  1. On-Demand Droplet Capture and Release Using Microwell-Assisted Surface Acoustic Waves.

    PubMed

    Jung, Jin Ho; Destgeer, Ghulam; Park, Jinsoo; Ahmed, Husnain; Park, Kwangseok; Sung, Hyung Jin

    2017-02-21

    We demonstrate an acoustofluidic platform that uses surface acoustic waves (SAWs) for the facile capture of droplets inside microwells and their on-demand release. When the ac signal applied to the device is tuned to modulate the location of the SAW, the SAW-based acoustic radiation force retracts or pushes the droplets into or out of one of three microwells fabricated inside a microchannel to selectively capture or release the droplet.

  2. Monolithic GaAs surface acoustic wave chemical microsensor array

    SciTech Connect

    HIETALA,VINCENT M.; CASALNUOVO,STEPHEN A.; HELLER,EDWIN J.; WENDT,JOEL R.; FRYE-MASON,GREGORY CHARLES; BACA,ALBERT G.

    2000-03-09

    A four-channel surface acoustic wave (SAW) chemical sensor array with associated RF electronics is monolithically integrated onto one GaAs IC. The sensor operates at 690 MHz from an on-chip SAW based oscillator and provides simple DC voltage outputs by using integrated phase detectors. This sensor array represents a significant advance in microsensor technology offering miniaturization, increased chemical selectivity, simplified system assembly, improved sensitivity, and inherent temperature compensation.

  3. Optimum contact conditions for miniaturized surface acoustic wave linear motor

    PubMed

    Takasaki; Kurosawa; Higuchi

    2000-03-01

    This paper reports the successful operation of a 70 MHz driving surface acoustic wave (SAW) linear motor with a miniaturized stator transducer. This paper also deals with an investigation into an optimized slider design for the miniaturized SAW linear motor. The performance of three silicon type sliders, with different projection size, was compared. Output forces of the three sliders were measured with change of pre-load. It was found that the slider with smaller projection tended to produce greater output force.

  4. Frequency effect on streaming phenomenon induced by Rayleigh surface acoustic wave in microdroplets

    NASA Astrophysics Data System (ADS)

    Alghane, M.; Fu, Y. Q.; Chen, B. X.; Li, Y.; Desmulliez, M. P. Y.; Walton, A. J.

    2012-10-01

    Acoustic streaming of ink particles inside a water microdroplet generated by a surface acoustic wave (SAW) has been studied numerically using a finite volume numerical method and these results have been verified using experimental measurements. Effects of SAW excitation frequency, droplet volume, and radio-frequency (RF) power are investigated, and it has been shown that SAW excitation frequency influences the SAW attenuation length, lSAW, and hence the acoustic energy absorbed by liquid. It has also been observed that an increase of excitation frequency generally enhances the SAW streaming behavior. However, when the frequency exceeds a critical value that depends on the RF power applied to the SAW device, weaker acoustic streaming is observed resulting in less effective acoustic mixing inside the droplet. This critical value is characterised by a dimensionless ratio of droplet radius to SAW attenuation length, i.e., Rd/lSAW. With a mean value of Rd/lSAW ≈ 1, a fast and efficient mixing can be induced, even at the lowest RF power of 0.05 mW studied in this paper. On the other hand, for the Rd/lSAW ratios much larger than ˜1, significant decreases in streaming velocities were observed, resulting in a transition from regular (strong) to irregular (weak) mixing/flow. This is attributed to an increased absorption rate of acoustic wave energy that leaks into the liquid, resulting in a reduction of the acoustic energy radiated away from the SAW interaction region towards the droplet free surface. It has been demonstrated in this study that a fast and efficient mixing process with a smaller RF power could be achieved if the ratio of Rd/lSAW ≤ 1 in the SAW-droplet based microfluidics.

  5. Transporting and manipulating single electrons in surface-acoustic-wave minima

    NASA Astrophysics Data System (ADS)

    Ford, Christopher J. B.

    2017-03-01

    A surface acoustic wave (SAW) can produce a moving potential wave that can trap and drag electrons along with it. We review work on using a SAW to create moving quantum dots containing single electrons, with the aims of developing a current standard, emitting single photons, transferring single electrons between static quantum dots, and investigating non-adiabatic effects.

  6. Quantum positron acoustic waves

    SciTech Connect

    Metref, Hassina; Tribeche, Mouloud

    2014-12-15

    Nonlinear quantum positron-acoustic (QPA) waves are investigated for the first time, within the theoretical framework of the quantum hydrodynamic model. In the small but finite amplitude limit, both deformed Korteweg-de Vries and generalized Korteweg-de Vries equations governing, respectively, the dynamics of QPA solitary waves and double-layers are derived. Moreover, a full finite amplitude analysis is undertaken, and a numerical integration of the obtained highly nonlinear equations is carried out. The results complement our previously published results on this problem.

  7. Integrated microfluidics system using surface acoustic wave and electrowetting on dielectrics technology.

    PubMed

    Li, Y; Fu, Y Q; Brodie, S D; Alghane, M; Walton, A J

    2012-03-01

    This paper presents integrated microfluidic lab-on-a-chip technology combining surface acoustic wave (SAW) and electro-wetting on dielectric (EWOD). This combination has been designed to provide enhanced microfluidic functionality and the integrated devices have been fabricated using a single mask lithographic process. The integrated technology uses EWOD to guide and precisely position microdroplets which can then be actuated by SAW devices for particle concentration, acoustic streaming, mixing and ejection, as well as for sensing using a shear-horizontal wave SAW device. A SAW induced force has also been employed to enhance the EWOD droplet splitting function.

  8. New Biosensor Using Shear Horizontal Surface Acoustic Wave Device

    NASA Astrophysics Data System (ADS)

    Kondoh, Jun; Matsui, Yoshikazu; Shiokawa, Showko

    1993-05-01

    This paper describes a new biosensor to detect an enzyme reaction in liquid using surface acoustic wave (SAW) devices fabricated on 36°-rotated Y-cut, X-propagating LiTaO3. The sensing wave on the substrate is a predominantly shear-horizontal-mode SAW (SH-SAW) and is affected by a strong acoustoelectric interaction between the piezoelectric potential and electrical properties of the materials in the adjacent liquid. As an example of an electrical property, pH change associated with an enzyme reaction leads to measurable perturbation in the wave-propagation characteristic. Taking advantage of this phenomenon we realized a SAW biosensor which consists of an immobilized urease membrane on the surface. Also, highly sensitive detection for the urea solution was obtained in our preliminary experiments.

  9. Surface acoustic wave devices including Langmuir-Blodgett films (Review)

    NASA Astrophysics Data System (ADS)

    Plesskii, V. P.

    1991-06-01

    Recent theoretical and experimental research related to the use of Langmuir-Blodgett (LB) films in surface acoustic wave (SAW) devices is reviewed. The sensitivity of the different cuts of quartz and lithium niobate to inertial loading is investigated, and it is shown that some cuts in lithium niobate are twice as sensitive to mass loading than the commonly used YZ-cut. The large variety of organic compounds suitable for the production of LB films makes it possible to create SAW sensors reacting selectively to certain substances. The existing SAW sensors based on LB films are characterized by high sensitivity and fast response.

  10. Ultrafast microfluidics using surface acoustic waves

    PubMed Central

    Yeo, Leslie Y.; Friend, James R.

    2009-01-01

    We demonstrate that surface acoustic waves (SAWs), nanometer amplitude Rayleigh waves driven at megahertz order frequencies propagating on the surface of a piezoelectric substrate, offer a powerful method for driving a host of extremely fast microfluidic actuation and micro∕bioparticle manipulation schemes. We show that sessile drops can be translated rapidly on planar substrates or fluid can be pumped through microchannels at 1–10 cm∕s velocities, which are typically one to two orders quicker than that afforded by current microfluidic technologies. Through symmetry-breaking, azimuthal recirculation can be induced within the drop to drive strong inertial microcentrifugation for micromixing and particle concentration or separation. Similar micromixing strategies can be induced in the same microchannel in which fluid is pumped with the SAW by merely changing the SAW frequency to rapidly switch the uniform through-flow into a chaotic oscillatory flow by exploiting superpositioning of the irradiated sound waves from the sidewalls of the microchannel. If the flow is sufficiently quiescent, the nodes of the transverse standing wave that arises across the microchannel also allow for particle aggregation, and hence, sorting on nodal lines. In addition, the SAW also facilitates other microfluidic capabilities. For example, capillary waves excited at the free surface of a sessile drop by the SAW underneath it can be exploited for micro∕nanoparticle collection and sorting at nodal points or lines at low powers. At higher powers, the large accelerations off the substrate surface as the SAW propagates across drives rapid destabilization of the drop free surface giving rise to inertial liquid jets that persist over 1–2 cm in length or atomization of the entire drop to produce 1–10 μm monodispersed aerosol droplets, which can be exploited for ink-jet printing, mass spectrometry interfacing, or pulmonary drug delivery. The atomization of polymer∕protein solutions

  11. Absorption of surface acoustic waves by topological insulator thin films

    SciTech Connect

    Li, L. L.; Xu, W.

    2014-08-11

    We present a theoretical study on the absorption of the surface acoustic waves (SAWs) by Dirac electrons in topological insulator (TI) thin films (TITFs). We find that due to momentum and energy conservation laws, the absorption of the SAWs in TITFs can only be achieved via intra-band electronic transitions. The strong absorption can be observed up to sub-terahertz frequencies. With increasing temperature, the absorption intensity increases significantly and the cut-off frequency is blue-shifted. More interestingly, we find that the absorption of the SAWs by the TITFs can be markedly enhanced by the tunable subgap in the Dirac energy spectrum of the TI surface states. Such a subgap is absent in conventional two-dimensional electron gases (2DEGs) and in the gapless Dirac 2DEG such as graphene. This study is pertinent to the exploration of the acoustic properties of TIs and to potential application of TIs as tunable SAW devices working at hypersonic frequencies.

  12. Absorption of surface acoustic waves by topological insulator thin films

    NASA Astrophysics Data System (ADS)

    Li, L. L.; Xu, W.

    2014-08-01

    We present a theoretical study on the absorption of the surface acoustic waves (SAWs) by Dirac electrons in topological insulator (TI) thin films (TITFs). We find that due to momentum and energy conservation laws, the absorption of the SAWs in TITFs can only be achieved via intra-band electronic transitions. The strong absorption can be observed up to sub-terahertz frequencies. With increasing temperature, the absorption intensity increases significantly and the cut-off frequency is blue-shifted. More interestingly, we find that the absorption of the SAWs by the TITFs can be markedly enhanced by the tunable subgap in the Dirac energy spectrum of the TI surface states. Such a subgap is absent in conventional two-dimensional electron gases (2DEGs) and in the gapless Dirac 2DEG such as graphene. This study is pertinent to the exploration of the acoustic properties of TIs and to potential application of TIs as tunable SAW devices working at hypersonic frequencies.

  13. A Comparison of Surface Acoustic Wave Modeling Methods

    NASA Technical Reports Server (NTRS)

    Wilson, W. c.; Atkinson, G. M.

    2009-01-01

    Surface Acoustic Wave (SAW) technology is low cost, rugged, lightweight, extremely low power and can be used to develop passive wireless sensors. For these reasons, NASA is investigating the use of SAW technology for Integrated Vehicle Health Monitoring (IVHM) of aerospace structures. To facilitate rapid prototyping of passive SAW sensors for aerospace applications, SAW models have been developed. This paper reports on the comparison of three methods of modeling SAWs. The three models are the Impulse Response Method a first order model, and two second order matrix methods; the conventional matrix approach, and a modified matrix approach that is extended to include internal finger reflections. The second order models are based upon matrices that were originally developed for analyzing microwave circuits using transmission line theory. Results from the models are presented with measured data from devices.

  14. Multilayer-graphene-based amplifier of surface acoustic waves

    SciTech Connect

    Yurchenko, Stanislav O. Komarov, Kirill A.; Pustovoit, Vladislav I.

    2015-05-15

    The amplification of surface acoustic waves (SAWs) by a multilayer graphene (MLG)-based amplifier is studied. The conductivity of massless carriers (electrons or holes) in graphene in an external drift electric field is calculated using Boltzmann’s equation. At some carrier drift velocities, the real part of the variable conductivity becomes negative and MLG can be employed in SAW amplifiers. Amplification of Blustein’s and Rayleigh’s SAWs in CdS, a piezoelectric hexagonal crystal of the symmetry group C{sub 6v}, is considered. The corresponding equations for SAW propagation in the device are derived and can be applied to other substrate crystals of the same symmetry. The results of the paper indicate that MLG can be considered as a perspective material for SAW amplification and related applications.

  15. Multilayer-graphene-based amplifier of surface acoustic waves

    NASA Astrophysics Data System (ADS)

    Yurchenko, Stanislav O.; Komarov, Kirill A.; Pustovoit, Vladislav I.

    2015-05-01

    The amplification of surface acoustic waves (SAWs) by a multilayer graphene (MLG)-based amplifier is studied. The conductivity of massless carriers (electrons or holes) in graphene in an external drift electric field is calculated using Boltzmann's equation. At some carrier drift velocities, the real part of the variable conductivity becomes negative and MLG can be employed in SAW amplifiers. Amplification of Blustein's and Rayleigh's SAWs in CdS, a piezoelectric hexagonal crystal of the symmetry group C6v, is considered. The corresponding equations for SAW propagation in the device are derived and can be applied to other substrate crystals of the same symmetry. The results of the paper indicate that MLG can be considered as a perspective material for SAW amplification and related applications.

  16. Surface acoustic-wave piezoelectric crystal aerosol mass microbalance

    NASA Astrophysics Data System (ADS)

    Bowers, W. D.; Chuan, R. L.

    1989-07-01

    The development of a particulate mass-sensing instrument based on a quartz-crystal microbalance and enhanced with the new surface acoustic-wave (SAW) technology is reported. Mass sensitivity comparisons of a 158-MHz SAW piezoelectric microbalance and a conventional 10-MHz quartz-crystal microbalance show that the SAW crystal is 266 times more sensitive, in good agreement with the theoretical value of 250. The frequency stability of a single SAW resonator is 6 parts in 10 to the 8th over 1 min. The response to temperature changes is found to be very linear over the range +30 to -30 C. A strong response to 15 ppm SO2 has been demonstrated on a chemically coated SAW crystal.

  17. Guided acoustic wave inspection system

    SciTech Connect

    Chinn, Diane J.

    2004-10-05

    A system for inspecting a conduit for undesirable characteristics. A transducer system induces guided acoustic waves onto said conduit. The transducer system detects the undesirable characteristics of the conduit by receiving guided acoustic waves that contain information about the undesirable characteristics. The conduit has at least two sides and the transducer system utilizes flexural modes of propagation to provide inspection using access from only the one side of the conduit. Cracking is detected with pulse-echo testing using one transducer to both send and receive the guided acoustic waves. Thinning is detected in through-transmission testing where one transducer sends and another transducer receives the guided acoustic waves.

  18. A surface-acoustic-wave-based cantilever bio-sensor.

    PubMed

    De Simoni, Giorgio; Signore, Giovanni; Agostini, Matteo; Beltram, Fabio; Piazza, Vincenzo

    2015-06-15

    A scalable surface-acoustic-wave- (SAW-) based cantilevered device for portable bio-chemical sensing applications is presented. Even in the current, proof-of-principle implementation this architecture is shown to outperform commercial quartz-crystal microbalances in terms of sensitivity. Adhesion of analytes on a functionalized surface of the cantilever shifts the resonant frequency of a SAW-generating transducer due to the stress-induced variation of the speed of surface acoustic modes. We discuss the relevance of this approach for diagnostics applications based on miniaturized devices.

  19. Anisotropic Swirling Surface Acoustic Waves from Inverse Filtering for On-Chip Generation of Acoustic Vortices

    NASA Astrophysics Data System (ADS)

    Riaud, Antoine; Thomas, Jean-Louis; Charron, Eric; Bussonnière, Adrien; Bou Matar, Olivier; Baudoin, Michael

    2015-09-01

    From radio-electronics signal analysis to biological sample actuation, surface acoustic waves (SAWs) are involved in a multitude of modern devices. However, only the most simple standing or progressive waves such as plane and focused waves have been explored so far. In this paper, we expand the SAW toolbox with a wave family named "swirling surface acoustic waves" which are the 2D anisotropic analogue of bulk acoustic vortices. Similarly to their 3D counterpart, they appear as concentric structures of bright rings with a phase singularity in their center resulting in a central dark spot. After the rigorous mathematical definition of these waves, we synthesize them experimentally through the inverse filtering technique revisited for surface waves. For this purpose, we design a setup combining arrays of interdigitated transducers and a multichannel electronic that enables one to synthesize any prescribed wave field compatible with the anisotropy of the substrate in a region called the "acoustic scene." This work opens prospects for the design of integrated acoustic vortex generators for on-chip selective acoustic tweezing.

  20. Surface Acoustic Wave Vibration Sensors for Measuring Aircraft Flutter

    NASA Technical Reports Server (NTRS)

    Wilson, William C.; Moore, Jason P.; Juarez, Peter D.

    2016-01-01

    Under NASA's Advanced Air Vehicles Program the Advanced Air Transport Technology (AATT) Project is investigating flutter effects on aeroelastic wings. To support that work a new method for measuring vibrations due to flutter has been developed. The method employs low power Surface Acoustic Wave (SAW) sensors. To demonstrate the ability of the SAW sensor to detect flutter vibrations the sensors were attached to a Carbon fiber-reinforced polymer (CFRP) composite panel which was vibrated at six frequencies from 1Hz to 50Hz. The SAW data was compared to accelerometer data and was found to resemble sine waves and match each other closely. The SAW module design and results from the tests are presented here.

  1. Microfluidic particle manipulation using high frequency surface acoustic waves

    NASA Astrophysics Data System (ADS)

    Ai, Ye; Collins, David J.

    2016-11-01

    Precise manipulation of particles and biological cells remains a very active research area in microfluidics. Among various force fields applied for microfluidic manipulations, acoustic waves have superior propagating properties in solids and fluids, which can readily enable non-contact cell manipulation in long operating distances. Exploiting acoustic waves for fluid and cell manipulation in microfluidics has led to a newly emerging research area, acoustofluidics. In this work, I will present particle and cell manipulation in microfluidics using high frequency surface acoustic waves (SAW). In particular, I will discuss a unique design of a focused IDT (FIDT) structure, which is able to generate a highly localized SAW field on the order of 20 µm wide. This highly focused acoustic beam has an effective manipulation area size that is comparable to individual micron-sized particles. Here, I demonstrate the use of this highly localized SAW field for single particle level sorting with sub-millisecond pulses and selective capture of particles. Based on the presented studies on acoustic particle manipulation, I envision that the merging of acoustics and microfluidics could enable various particle and cell manipulations needed in microfluidic applications. We acknowledge the support received from Singapore University of Technology and Design (SUTD)-Massachusetts Institute of Technology (MIT) International Design Center (IDG11300101) and SUTD Startup Research Grant (SREP13053) awarded to Y.A.

  2. Amplification and directional emission of surface acoustic waves by a two-dimensional electron gas

    SciTech Connect

    Shao, Lei; Pipe, Kevin P.

    2015-01-12

    Amplification of surface acoustic waves (SAWs) by electron drift in a two-dimensional electron gas (2DEG) is analyzed analytically and confirmed experimentally. Calculations suggest that peak power gain per SAW radian occurs at a more practical carrier density for a 2DEG than for a bulk material. It is also shown that SAW emission with tunable directionality can be achieved by modulating a 2DEG's carrier density (to effect SAW generation) in the presence of an applied DC field that amplifies SAWs propagating in a particular direction while attenuating those propagating in the opposite direction.

  3. Surface Acoustic Wave Ammonia Sensors Based on ST-cut Quartz under Periodic Al Structure.

    PubMed

    Hsu, Cheng-Liang; Shen, Chi-Yen; Tsai, Rume-Tze; Su, Ming-Yau

    2009-01-01

    Surface acoustic wave (SAW) devices are key components for sensing applications. SAW propagation under a periodic grating was investigated in this work. The theoretical method used here is the space harmonic method. We also applied the results of SAW propagation studied in this work to design a two-port resonator with an Al grating on ST-cut quartz. The measured frequency responses of the resonator were similar to the simulation ones. Then, the chemical interface of polyaniline/WO(3) composites was coated on the SAW sensor for ammonia detection. The SAW sensor responded to ammonia gas and could be regenerated using dry nitrogen.

  4. Molecular recognition in gas sensing: Results from acoustic wave and in-situ FTIR measurements

    SciTech Connect

    Hierlemann, A.; Ricco, A.J.; Bodenhoefer, K.; Goepel, W.

    1998-06-01

    Surface acoustic wave (SAW) measurements were combined with direct, in-situ molecular spectroscopy to understand the interactions of surface-confined sensing films with gas-phase analytes. This was accomplished by collecting Fourier-transform infrared external-reflectance spectra (FTIR-ERS) on operating SAW devices during dosing of their specifically coated surfaces with key analytes.

  5. An all fiber-optic sensor for surface acoustic wave measurements

    NASA Technical Reports Server (NTRS)

    Bowers, J. E.; Jungerman, R. L.; Khuri-Yakub, B. T.; Kino, G. S.

    1983-01-01

    A surface acoustic wave (SAW) sensor constructed from single-mode fiber-optic components is described. An analysis of reciprocal and nonreciprocal modes of operation of the sensor is presented. Results from measurements on a variety of SAW devices illustrate the use of the sensor. The amplitude sensitivity is 0.0003 A for an integration time of 0.1 s.

  6. Resonant attenuation of surface acoustic waves by a disordered monolayer of microspheres

    NASA Astrophysics Data System (ADS)

    Eliason, J. K.; Vega-Flick, A.; Hiraiwa, M.; Khanolkar, A.; Gan, T.; Boechler, N.; Fang, N.; Nelson, K. A.; Maznev, A. A.

    2016-02-01

    Attenuation of surface acoustic waves (SAWs) by a disordered monolayer of polystyrene microspheres is investigated. Surface acoustic wave packets are generated by a pair of crossed laser pulses in a glass substrate coated with a thin aluminum film and detected via the diffraction of a probe laser beam. When a 170 μm-wide strip of micron-sized spheres is placed on the substrate between the excitation and detection spots, strong resonant attenuation of SAWs near 240 MHz is observed. The attenuation is caused by the interaction of SAWs with a contact resonance of the microspheres, as confirmed by acoustic dispersion measurements on the microsphere-coated area. Frequency-selective attenuation of SAWs by such a locally resonant metamaterial may lead to reconfigurable SAW devices and sensors, which can be easily manufactured via self-assembly techniques.

  7. Buzz-saw noise : propagation of shock waves in aero-engine inlet ducts

    NASA Astrophysics Data System (ADS)

    Fernando, Rasika; Marchiano, Régis; Coulouvrat, François; Druon, Yann

    2008-06-01

    For supersonic flows relative to turbo-engine fan blades, measured acoustic spectra near the inlet present tones at fan blade passing frequency (BPF), engine shaft rotation frequency, or Engine Order (EO), and their respective harmonics. The latter are responsible for the Buzz-saw noise and are thus referred to as "Buzz-saw" or "multiple pure" tones. This work first attempts to reformulate McAlpine and Fisher's frequency domain model (2001) for the propagation of a unidimensional sawtooth waveform spiralling inside a hard-walled cylindrical duct in the presence of a uniform flow. The non-dissipative Burgers equation is solved using a shock fitting method, and modal attenuation and dispersion are added using a split-step computational method. In practice, shocks do not only occur at blade tips but on a significant portion of the blade span. The plane wave hypothesis being no longer valid, a new three dimensional model is required. This model is based on the computation of the axially varying amplitudes of the modal solutions, in order to take into account the nonlinear modal interactions.

  8. Fabrication, Operation and Flow Visualization in Surface-acoustic-wave-driven Acoustic-counterflow Microfluidics

    PubMed Central

    Travagliati, Marco; Shilton, Richie; Beltram, Fabio; Cecchini, Marco

    2013-01-01

    Surface acoustic waves (SAWs) can be used to drive liquids in portable microfluidic chips via the acoustic counterflow phenomenon. In this video we present the fabrication protocol for a multilayered SAW acoustic counterflow device. The device is fabricated starting from a lithium niobate (LN) substrate onto which two interdigital transducers (IDTs) and appropriate markers are patterned. A polydimethylsiloxane (PDMS) channel cast on an SU8 master mold is finally bonded on the patterned substrate. Following the fabrication procedure, we show the techniques that allow the characterization and operation of the acoustic counterflow device in order to pump fluids through the PDMS channel grid. We finally present the procedure to visualize liquid flow in the channels. The protocol is used to show on-chip fluid pumping under different flow regimes such as laminar flow and more complicated dynamics characterized by vortices and particle accumulation domains. PMID:24022515

  9. Surface acoustic wave gas sensor based on film conductivity changes

    NASA Astrophysics Data System (ADS)

    Ricco, A. J.; Martin, S. J.; Zipperian, T. E.

    1985-12-01

    The first surfce acoustic wave (SAW) sensor that functions via changes in conductivity of a thin surface film is reported. A lead phthalocyanine (PbPc) thin film is deposted on the acoustic progagation path of a LiNbO3 SAW delay line, which serves as the feedback element of an oscillator circuit. Reaction with strongly oxidizing gases, in particular NO2, increases the conductivity of the PbPc film. Acoustoelectric coupling of the traveling electric potential wave associated with the SAW-to-charge carriers in the PbPc film slows the acoustic wave velocity, altering the oscillation frequency of the circuit. This sensor is about 1000 times more sensitive, in terms of the number of NO2 molecules that can be detected (10 to the 16th molecules/cu cm of PbPc film), than an identical SAW sensor functioning via mass loading would be. Sensitivity to a few ppm of NO2 in N2 has been demonstrated.

  10. Surface acoustic wave gas sensor based on film conductivity changes

    NASA Astrophysics Data System (ADS)

    Ricco, A. J.; Martin, S. J.; Zipperian, T. E.

    The first surface acoustic wave (SAW) sensor that functions via changes in conductivity of a thin surface film is reported. A lead phthalocyanine (PbPc) thin film is deposited on the acoustic propagation path of a LiNbO3 SAW delay line, which serves as the feedback element of an oscillator circuit. Reaction with strongly oxidizing gases, in particular NO2, increases the conductivity of the PbPc film. Acoustoelectic coupling of the traveling electric potential wave associated with the SAW-to-charge carriers in the PbPc film slows the acoustic wave velocity, altering the oscillation frequency of the circuit. This sensor is about 1000 times more sensitive, in terms of the number of NO2 molecules that can be detected (10 to the 16th molecules/cu cm of PbPc film), than an identical SAW sensor functioning via mass loading would be. Sensitivity to a few ppm of NO2 in Ne was demonstrated.

  11. Transport Powder and Liquid Samples by Surface Acoustic Waves

    NASA Technical Reports Server (NTRS)

    Bao, Xiaoqi; Bar-Cohen, Yoseph; Sherrit, Stewart; Badescu, Mircea; Louyeh, Sahar

    2009-01-01

    Sample transport is an important requirement for In-situ analysis of samples in NASA planetary exploration missions. Tests have shown that powders or liquid drops on a surface can be transported by surface acoustic waves (SAW) that are generated on the surface using interdigital transducers. The phenomena were investigated experimentally and to generate SAWs interdigital electrodes were deposited on wafers of 128 deg rotated Y-cut LiNbO?. Transporting capability of the SAW device was tested using particles of various sizes and drops of various viscosities liquids. Because of different interaction mechanisms with the SAWs, the powders and the liquid drops were observed to move in opposite directions. In the preliminary tests, a speed of 180 mm/s was achieved for powder transportation. The detailed experimental setup and results are presented in this paper. The transporting mechanism can potentially be applied to miniaturize sample analysis system or " lab-on-chip" devices.

  12. Subharmonic phased array for crack evaluation using surface acoustic wave

    NASA Astrophysics Data System (ADS)

    Ouchi, Akihiro; Sugawara, Azusa; Ohara, Yoshikazu; Yamanaka, Kazushi

    2015-07-01

    To accurately measure closed crack length, we proposed an imaging method using a subharmonic phased array for crack evaluation using surface acoustic waves (SAW SPACE) with water immersion. We applied SAW SPACE to the hole specimen in a fundamental array (FA) image. The hole was imaged with high resolution. Subsequently, SAW SPACE was applied to fatigue crack and stress corrosion crack (SCC) specimens. A fatigue crack was imaged in FA and subharmonic array (SA) images, and the length of this particular fatigue crack measured in the images was almost the same as that measured by optical observation. The SCC was imaged and its length was accurately measured in the SA image, whereas it was underestimated in the FA image and by optical observation. Thus, we demonstrated that SAW SPACE with water immersion is useful for the accurate measurement of closed crack length and for imaging the distribution of open and closed parts of cracks with high resolution.

  13. Nozzleless Spray Cooling Using Surface Acoustic Waves

    NASA Astrophysics Data System (ADS)

    Ang, Kar Man; Yeo, Leslie; Friend, James; Hung, Yew Mun; Tan, Ming Kwang

    2015-11-01

    Due to its reliability and portability, surface acoustic wave (SAW) atomization is an attractive approach for the generation of monodispersed microdroplets in microfluidics devices. Here, we present a nozzleless spray cooling technique via SAW atomization with key advantage of downward scalability by simply increasing the excitation frequency. With generation of micron size droplets through surface destabilization using SAW, the clogging issues commonly encountered by spraying nozzle can be neutralized. Using deionised water, cooling is improved when the atomization rate is increased and the position of the device is optimized such that the atomized droplets can be easily seeded into the upstream of the flow circulation. Cooling is further improved with the use of nanofluids; a suspension of nanoparticles in water. By increasing nanoparticle mass concentration from 1% to 3%, cooling is enhanced due to the deposition and formation of nanoparticle clusters on heated surface and eventually increase the surface area. However, further increase the concentration to 10% reduces the cooling efficiency due to drastic increase in viscosity μ that leads to lower atomization rate which scales as ṁ ~μ - 1 / 2 .

  14. Surface acoustic wave devices for sensor applications

    NASA Astrophysics Data System (ADS)

    Bo, Liu; Xiao, Chen; Hualin, Cai; Mohammad, Mohammad Ali; Xiangguang, Tian; Luqi, Tao; Yi, Yang; Tianling, Ren

    2016-02-01

    Surface acoustic wave (SAW) devices have been widely used in different fields and will continue to be of great importance in the foreseeable future. These devices are compact, cost efficient, easy to fabricate, and have a high performance, among other advantages. SAW devices can work as filters, signal processing units, sensors and actuators. They can even work without batteries and operate under harsh environments. In this review, the operating principles of SAW sensors, including temperature sensors, pressure sensors, humidity sensors and biosensors, will be discussed. Several examples and related issues will be presented. Technological trends and future developments will also be discussed. Project supported by the National Natural Science Foundation of China (Nos. 60936002, 61025021, 61434001, 61574083), the State Key Development Program for Basic Research of China (No. 2015CB352100), the National Key Project of Science and Technology (No. 2011ZX02403-002) and the Special Fund for Agroscientific Research in the Public Interest of China (No. 201303107). M.A.M is additionally supported by the Postdoctoral Fellowship (PDF) program of the Natural Sciences and Engineering Research Council (NSERC) of Canada and the China Postdoctoral Science Foundation (CPSF).

  15. Multiple-frequency surface acoustic wave devices as sensors

    NASA Astrophysics Data System (ADS)

    Ricco, Antonio J.; Martin, Stephen J.

    We have designed, fabricated, and tested a multiple-frequency acoustic wave (MUFAW) device on ST-cut quartz with nominal surface acoustic wave (SAW) center frequencies of 16, 40, 100, and 250 MHz. The four frequencies are obtained by patterning four sets of input and output interdigital transducers of differing periodicities on a single substrate. Such a device allows the frequency dependence of AW sensor perturbations to be examined, aiding in the elucidation of the operative interaction mechanism(s). Initial measurements of the SAW response to the vacuum deposition of a thin nickel film show the expected frequency dependence of mass sensitivity in addition to the expected frequency independence of the magnitude of the acoustoelectric effect. By measuring changes in both wave velocity and attenuation at multiple frequencies, extrinsic perturbations such as temperature and pressure changes are readily differentiated from one another and from changes in surface mass.

  16. Acoustic tweezers via sub–time-of-flight regime surface acoustic waves

    PubMed Central

    Collins, David J.; Devendran, Citsabehsan; Ma, Zhichao; Ng, Jia Wei; Neild, Adrian; Ai, Ye

    2016-01-01

    Micrometer-scale acoustic waves are highly useful for refined optomechanical and acoustofluidic manipulation, where these fields are spatially localized along the transducer aperture but not along the acoustic propagation direction. In the case of acoustic tweezers, such a conventional acoustic standing wave results in particle and cell patterning across the entire width of a microfluidic channel, preventing selective trapping. We demonstrate the use of nanosecond-scale pulsed surface acoustic waves (SAWs) with a pulse period that is less than the time of flight between opposing transducers to generate localized time-averaged patterning regions while using conventional electrode structures. These nodal positions can be readily and arbitrarily positioned in two dimensions and within the patterning region itself through the imposition of pulse delays, frequency modulation, and phase shifts. This straightforward concept adds new spatial dimensions to which acoustic fields can be localized in SAW applications in a manner analogous to optical tweezers, including spatially selective acoustic tweezers and optical waveguides. PMID:27453940

  17. Acoustic carrier transportation induced by surface acoustic waves in graphene in solution

    NASA Astrophysics Data System (ADS)

    Okuda, Satoshi; Ikuta, Takashi; Kanai, Yasushi; Ono, Takao; Ogawa, Shinpei; Fujisawa, Daisuke; Shimatani, Masaaki; Inoue, Koichi; Maehashi, Kenzo; Matsumoto, Kazuhiko

    2016-04-01

    The acoustic charge transportation induced by surface acoustic wave (SAW) propagation in graphene in solution was investigated. The sign of acoustic current (I A) was found to switch when crossing the Dirac point because the major carrier was transitioned from holes to electrons by the change in electrolyte-gate voltage. I A also exhibited a peak value under conditions of both hole and electron conduction. These results can be explained on the basis of a change in the type of major carrier in graphene, as well as a change in the carrier mobility of graphene.

  18. Ray splitting in the reflection and refraction of surface acoustic waves in anisotropic solids.

    PubMed

    Every, A G; Maznev, A A

    2010-05-01

    This paper examines the conditions for, and provides examples of, ray splitting in the reflection and refraction of surface acoustic waves (SAW) in elastically anisotropic solids at straight obstacles such as edges, surface breaking cracks, and interfaces between different solids. The concern here is not with the partial scattering of an incident SAW's energy into bulk waves, but with the occurrence of more than one SAW ray in the reflected and/or transmitted wave fields, by analogy with birefringence in optics and mode conversion of bulk elastic waves at interfaces. SAW ray splitting is dependent on the SAW slowness curve possessing concave regions, which within the constraint of wave vector conservation parallel to the obstacle allows multiple outgoing SAW modes for certain directions of incidence and orientation of obstacle. The existence of pseudo-SAW for a given surface provides a further channel for ray splitting. This paper discusses some typical material configurations for which SAW ray splitting occurs. An example is provided of mode conversion entailing backward reflection or negative refraction. Experimental demonstration of ray splitting in the reflection of a laser generated SAW in GaAs(111) is provided. The calculation of SAW mode conversion amplitudes lies outside the scope of this paper.

  19. Two true surface acoustic waves and other acoustic modes in (110) plane of Li2B4O7 substrate

    NASA Astrophysics Data System (ADS)

    Zhang, Victor Y.; Lefebvre, J. E.; Gryba, T.

    1999-09-01

    The surface acoustic waves (SAWs) and other acoustic modes propagating in the (110) plane of Li2B4O7 are investigated by means of the effective surface permittivity (ESP). It is demonstrated that the velocity of all piezoactive SAWs, both true and pseudo, as well as surface skimming bulk waves (SSBWs) can be numerically determined by computing the ESP as a function of acoustic trace slowness. A physical phenomenon not reported has been found for certain propagation directions, namely, simultaneous existence of two true SAWs, both being of the generalized Rayleigh type, together with a pseudo SAW of similar polarization. Propagation velocity, electromechanical coupling coefficient, and decay factor have been verified and confirmed by using two different sets of material constants and two numerical methods. The obtained values and accuracy of SAWs parameters are compared, and the validity conditions discussed. The generalized slowness diagram, plotted for the sagittal plane, enables to determine the total number of SSBW and to interpret the depth penetration properties of SAW. The Nyquist diagram of the ESP is shown to be a more helpful form for identifying a pseudo SAW and for distinguishing it from a SSBW.

  20. Enhanced sensitive love wave surface acoustic wave sensor designed for immunoassay formats.

    PubMed

    Puiu, Mihaela; Gurban, Ana-Maria; Rotariu, Lucian; Brajnicov, Simona; Viespe, Cristian; Bala, Camelia

    2015-05-05

    We report a Love wave surface acoustic wave (LW-SAW) immunosensor designed for the detection of high molecular weight targets in liquid samples, amenable also for low molecular targets in surface competition assays. We implemented a label-free interaction protocol similar to other surface plasmon resonance bioassays having the advantage of requiring reduced time analysis. The fabricated LW-SAW sensor supports the detection of the target in the nanomolar range, and can be ultimately incorporated in portable devices, suitable for point-of-care testing (POCT) applications.

  1. Mass sensitivity of layered shear-horizontal surface acoustic wave devices for sensing applications

    NASA Astrophysics Data System (ADS)

    Kalantar-Zadeh, Kourosh; Trinchi, Adrian; Wlodarski, Wojtek; Holland, Anthony; Galatsis, Kosmas

    2001-11-01

    Layered Surface Acoustic Wave (SAW) devices that allow the propagation of Love mode acoustic waves will be studied in this paper. In these devices, the substrate allows the propagation of Surface Skimming Bulks Waves (SSBWs). By depositing layers, that the speed of Shear Horizontal (SH) acoustic wave propagation is less than that of the substrate, the propagation mode transforms to Love mode. Love mode devices which will be studied in this paper, have SiO2 and ZnO acoustic guiding layers. As Love mode of propagation has no movement of particles component normal to the active sensor surface, they can be employed for the sensing applications in the liquid media.

  2. Canonical Acoustics and Its Application to Surface Acoustic Wave on Acoustic Metamaterials

    NASA Astrophysics Data System (ADS)

    Shen, Jian Qi

    2016-08-01

    In a conventional formalism of acoustics, acoustic pressure p and velocity field u are used for characterizing acoustic waves propagating inside elastic/acoustic materials. We shall treat some fundamental problems relevant to acoustic wave propagation alternatively by using canonical acoustics (a more concise and compact formalism of acoustic dynamics), in which an acoustic scalar potential and an acoustic vector potential (Φ ,V), instead of the conventional acoustic field quantities such as acoustic pressure and velocity field (p,u) for characterizing acoustic waves, have been defined as the fundamental variables. The canonical formalism of the acoustic energy-momentum tensor is derived in terms of the acoustic potentials. Both the acoustic Hamiltonian density and the acoustic Lagrangian density have been defined, and based on this formulation, the acoustic wave quantization in a fluid is also developed. Such a formalism of acoustic potentials is employed to the problem of negative-mass-density assisted surface acoustic wave that is a highly localized surface bound state (an eigenstate of the acoustic wave equations). Since such a surface acoustic wave can be strongly confined to an interface between an acoustic metamaterial (e.g., fluid-solid composite structures with a negative dynamical mass density) and an ordinary material (with a positive mass density), it will give rise to an effect of acoustic field enhancement on the acoustic interface, and would have potential applications in acoustic device design for acoustic wave control.

  3. Effect of viscoelastic film for shear horizontal surface acoustic wave on quartz

    NASA Astrophysics Data System (ADS)

    Goto, Mikihiro; Yatsuda, Hiromi; Kondoh, Jun

    2015-07-01

    A numerical analysis for the mass loading sensitivity of shear horizontal surface acoustic wave (SH-SAW) immunoassay biosensors on quartz has already been studied. However, the mass loading analysis is insufficient to explain the actual biosensor performance. To understand the SH-SAW biosensor performance, we analyze the effect of a viscoelastic film on SH-SAW biosensors. In this paper, a numerical analysis using a simple viscoelastic model for the SH-SAW biosensors is presented. In the theoretical model, the bioreaction layer on the SH-SAW biosensors can be treated as a viscoelastic film. The velocity changes of the 250 MHz SH-SAWs on quartz substrates, which are covered with bovine serum albumin (BSA) layers of different thicknesses, were measured and compared with the theoretical results obtained using the proposed viscoelastic model. Good agreement of the velocity changes of SH-SAWs versus changes in the viscoelastic film thickness between theoretical and experimental results was obtained.

  4. Acoustic charge transport induced by the surface acoustic wave in chemical doped graphene

    NASA Astrophysics Data System (ADS)

    Zheng, Shijun; Zhang, Hao; Feng, Zhihong; Yu, Yuanyuan; Zhang, Rui; Sun, Chongling; Liu, Jing; Duan, Xuexin; Pang, Wei; Zhang, Daihua

    2016-10-01

    A graphene/LiNbO3 hybrid device is used to investigate the acoustic induced charge transport in chemical doped graphene. The chemical doping of graphene via its physisorption of gas molecules affects the surface acoustic wave (SAW) charge carrier transport in a manner different from electric field drift. That transport induces doping dependent macroscopic acoustoelectric current. The chemical doping can manipulate majority carriers and induces unique acoustoelectric features. The observation is explained by a classical relaxation model. Eventually the device based on acoustoelectric current is proved to outperform the common chemiresistor for chemicals. Our finding provides insight into acoustic charge carrier transport during chemical doping. The doping affects interaction of carriers with SAW phonon and facilitates the understanding of nanoscale acoustoelectric effect. The exploration inspires potential acoustoelectric application for chemical detection involving emerging 2D nanomaterials.

  5. Effect of surface acoustic waves on the catalytic decomposition of ethanol employing a comb transducer for ultrasonic generation

    SciTech Connect

    S. J. Reese; D. H. Hurley; H.W. Rollins

    2006-04-01

    The effect of surface acoustic waves, generated on a silver catalyst using a comb transducer, on the catalytic decomposition of ethanol is examined. The comb transducer employs purely mechanical means for surface acoustic wave (SAW) transduction. Unlike interdigital SAW transducers on piezoelectric substrates, the complicating effects of heat generation due to electromechanical coupling, high electric fields between adjacent electrodes, and acoustoelectric currents are avoided. The ethanol decomposition reactions are carried out at 473 K. The rates of acetaldehyde and ethylene production are retarded when acoustic waves are applied. The rates recover to varying degrees when acoustic excitation ceases.

  6. Investigation into mass loading sensitivity of sezawa wave mode-based surface acoustic wave sensors.

    PubMed

    Mohanan, Ajay Achath; Islam, Md Shabiul; Ali, Sawal Hamid; Parthiban, R; Ramakrishnan, N

    2013-02-06

    In this work mass loading sensitivity of a Sezawa wave mode based surface acoustic wave (SAW) device is investigated through finite element method (FEM) simulation and the prospects of these devices to function as highly sensitive SAW sensors is reported. A ZnO/Si layered SAW resonator is considered for the simulation study. Initially the occurrence of Sezawa wave mode and displacement amplitude of the Rayleigh and Sezawa wave mode is studied for lower ZnO film thickness. Further, a thin film made of an arbitrary material is coated over the ZnO surface and the resonance frequency shift caused by mass loading of the film is estimated. It was observed that Sezawa wave mode shows significant sensitivity to change in mass loading and has higher sensitivity (eight times higher) than Rayleigh wave mode for the same device configuration. Further, the mass loading sensitivity was observed to be greater for a low ZnO film thickness to wavelength ratio. Accordingly, highly sensitive SAW sensors can be developed by coating a sensing medium over a layered SAW device and operating at Sezawa mode resonance frequency. The sensitivity can be increased by tuning the ZnO film thickness to wavelength ratio.

  7. Surface Acoustic Waves Enhance Neutrophil Killing of Bacteria

    PubMed Central

    Loike, John D.; Plitt, Anna; Kothari, Komal; Zumeris, Jona; Budhu, Sadna; Kavalus, Kaitlyn; Ray, Yonatan; Jacob, Harold

    2013-01-01

    Biofilms are structured communities of bacteria that play a major role in the pathogenicity of bacteria and are the leading cause of antibiotic resistant bacterial infections on indwelling catheters and medical prosthetic devices. Failure to resolve these biofilm infections may necessitate the surgical removal of the prosthetic device which can be debilitating and costly. Recent studies have shown that application of surface acoustic waves to catheter surfaces can reduce the incidence of infections by a mechanism that has not yet been clarified. We report here the effects of surface acoustic waves (SAW) on the capacity of human neutrophils to eradicate S. epidermidis bacteria in a planktonic state and within biofilms. Utilizing a novel fibrin gel system that mimics a tissue-like environment, we show that SAW, at an intensity of 0.3 mW/cm2, significantly enhances human neutrophil killing of S. epidermidis in a planktonic state and within biofilms by enhancing human neutrophil chemotaxis in response to chemoattractants. In addition, we show that the integrin CD18 plays a significant role in the killing enhancement observed in applying SAW. We propose from out data that this integrin may serve as mechanoreceptor for surface acoustic waves enhancing neutrophil chemotaxis and killing of bacteria. PMID:23936303

  8. Microfluidic pumping through miniaturized channels driven by ultra-high frequency surface acoustic waves

    SciTech Connect

    Shilton, Richie J.; Travagliati, Marco; Beltram, Fabio; Cecchini, Marco

    2014-08-18

    Surface acoustic waves (SAWs) are an effective means to pump fluids through microchannel arrays within fully portable systems. The SAW-driven acoustic counterflow pumping process relies on a cascade phenomenon consisting of SAW transmission through the microchannel, SAW-driven fluid atomization, and subsequent coalescence. Here, we investigate miniaturization of device design, and study both SAW transmission through microchannels and the onset of SAW-driven atomization up to the ultra-high-frequency regime. Within the frequency range from 47.8 MHz to 754 MHz, we show that the acoustic power required to initiate SAW atomization remains constant, while transmission through microchannels is most effective when the channel widths w ≳ 10 λ, where λ is the SAW wavelength. By exploiting the enhanced SAW transmission through narrower channels at ultra-high frequencies, we discuss the relevant frequency-dependent length scales and demonstrate the scaling down of internal flow patterns and discuss their impact on device miniaturization strategies.

  9. Drops subjected to surface acoustic waves: flow dynamics

    NASA Astrophysics Data System (ADS)

    Brunet, Philippe; Baudoin, Michael; Bou Matar, Olivier; Dynamique Des Systèmes Hors Equilibre Team; Aiman-Films Team

    2012-11-01

    Ultrasonic acoustic waves of frequency beyond the MHz are known to induce streaming flow in fluids that can be suitable to perform elementary operations in microfluidics systems. One of the currently appealing geometry is that of a sessile drop subjected to surface acoustic waves (SAW). Such Rayleigh waves produce non-trival actuation in the drop leading to internal flow, drop displacement, free-surface oscillations and atomization. We recently carried out experiments and numerical simulations that allowed to better understand the underlying physical mechanisms that couple acoustic propagation and fluid actuation. We varied the frequency and amplitude of actuation, as well as the properties of the fluid, and we measured the effects of these parameters on the dynamics of the flow. We compared these results to finite-elements numerical simulations.

  10. High-frequency shear-horizontal surface acoustic wave sensor

    DOEpatents

    Branch, Darren W

    2013-05-07

    A Love wave sensor uses a single-phase unidirectional interdigital transducer (IDT) on a piezoelectric substrate for leaky surface acoustic wave generation. The IDT design minimizes propagation losses, bulk wave interferences, provides a highly linear phase response, and eliminates the need for impedance matching. As an example, a high frequency (.about.300-400 MHz) surface acoustic wave (SAW) transducer enables efficient excitation of shear-horizontal waves on 36.degree. Y-cut lithium tantalate (LTO) giving a highly linear phase response (2.8.degree. P-P). The sensor has the ability to detect at the pg/mm.sup.2 level and can perform multi-analyte detection in real-time. The sensor can be used for rapid autonomous detection of pathogenic microorganisms and bioagents by field deployable platforms.

  11. High-frequency shear-horizontal surface acoustic wave sensor

    DOEpatents

    Branch, Darren W

    2014-03-11

    A Love wave sensor uses a single-phase unidirectional interdigital transducer (IDT) on a piezoelectric substrate for leaky surface acoustic wave generation. The IDT design minimizes propagation losses, bulk wave interferences, provides a highly linear phase response, and eliminates the need for impedance matching. As an example, a high frequency (.about.300-400 MHz) surface acoustic wave (SAW) transducer enables efficient excitation of shear-horizontal waves on 36.degree. Y-cut lithium tantalate (LTO) giving a highly linear phase response (2.8.degree. P-P). The sensor has the ability to detect at the pg/mm.sup.2 level and can perform multi-analyte detection in real-time. The sensor can be used for rapid autonomous detection of pathogenic microorganisms and bioagents by field deployable platforms.

  12. Surface acoustic wave micromotor with arbitrary axis rotational capability

    NASA Astrophysics Data System (ADS)

    Tjeung, Ricky T.; Hughes, Mark S.; Yeo, Leslie Y.; Friend, James R.

    2011-11-01

    A surface acoustic wave (SAW) actuated rotary motor is reported here, consisting of a millimeter-sized spherical metal rotor placed on the surface of a lead zirconate titanate piezoelectric substrate upon which the SAW is made to propagate. At the design frequency of 3.2 MHz and with a fixed preload of 41.1 μN, the maximum rotational speed and torque achieved were approximately 1900 rpm and 5.37 μN-mm, respectively, producing a maximum output power of 1.19 μW. The surface vibrations were visualized using laser Doppler vibrometry and indicate that the rotational motion arises due to retrograde elliptical motions of the piezoelectric surface elements. Rotation about orthogonal axes in the plane of the substrate has been obtained by using orthogonally placed interdigital electrodes on the substrate to generate SAW impinging on the rotor, offering a means to generate rotation about an arbitrary axis in the plane of the substrate.

  13. Cyclodextrin-based surface acoustic wave chemical microsensors

    SciTech Connect

    Li, D.Q.; Shi, J.X.; Springer, K.; Swanson, B.I.

    1996-07-01

    Cyclodextrin thin films were fabricated using either self-assembled monolayer (SAM) or solgel techniques. The resulting host receptor thin films on the substrates of surface acoustic wave (SAW) resonators were studied as method of tracking organic toxins in vapor phase. The mass loading of surface-attached host monolayers on SAW resonators gave frequency shifts corresponding to typical monolayer surface coverages for SAM methods and ``multilayer`` coverages for sol-gel techniques. Subsequent exposure of the coated SAW resonators to organic vapors at various concentrations, typically 5,000 parts per millions (ppm) down to 100 parts per billions (ppb) by mole, gave responses indicating middle-ppb-sensitivity ({approximately}50 ppb) for those sensor-host-receptors and organic-toxin pairs with optimum mutual matching of polarity, size, and structural properties.

  14. An Acoustic Charge Transport Imager for High Definition Television Applications: Low-Voltage SAW Amplifiers on Multilayer GaAs/ZnO Substrates

    NASA Technical Reports Server (NTRS)

    Hunt, W. D.; Brennan, K. F.; Summers, C. J.; Cameron, Thomas P.

    1996-01-01

    This thesis addresses the acoustoelectric issues concerning the amplification of surface acoustic waves (SAWs) and the reflection of SAWs from slanted reflector gratings on GaAs, with application to a novel acoustic charge transport (ACT) device architecture. First a simple model of the SAWAMP was developed, which was subsequently used to define the epitaxially grown material structure necessary to provide simultaneously high resistance and high electron mobility. In addition, a segmented SAWAMP structure was explored with line widths on the order of an acoustic wavelength. This resulted in the demonstration of SAWAMPS with an order of magnitude less voltage and power requirements than previously reported devices. A two-dimensional model was developed to explain the performance of devices with charge confinement layers less then 0.5 mm, which was experimentally verified. This model was extended to predict a greatly increased gain from the addition of a ZnO overlay. These overlays were experimentally attempted, but no working devices were reported due to process incompatibilities. In addition to the SAWAMP research, the reflection of SAWs from slanted gratings on GaAs was also studied and experimentally determined reflection coefficients for both 45 deg grooves and Al stripes on GaAs have been reported for the first time. The SAWAMp and reflector gratings were combined to investigate the integrated ring oscillator for application to the proposed ACT device and design parameters for this device have been provided.

  15. Multi-reflective acoustic wave device

    DOEpatents

    Andle, Jeffrey C.

    2006-02-21

    An acoustic wave device, which utilizes multiple localized reflections of acoustic wave for achieving an infinite impulse response while maintaining high tolerance for dampening effects, is disclosed. The device utilized a plurality of electromechanically significant electrodes disposed on most of the active surface. A plurality of sensors utilizing the disclosed acoustic wave mode device are also described.

  16. Frequency Domain Modeling of SAW Devices

    NASA Technical Reports Server (NTRS)

    Wilson, W. C.; Atkinson, G. M.

    2007-01-01

    New SAW sensors for integrated vehicle health monitoring of aerospace vehicles are being investigated. SAW technology is low cost, rugged, lightweight, and extremely low power. However, the lack of design tools for MEMS devices in general, and for Surface Acoustic Wave (SAW) devices specifically, has led to the development of tools that will enable integrated design, modeling, simulation, analysis and automatic layout generation of SAW devices. A frequency domain model has been created. The model is mainly first order, but it includes second order effects from triple transit echoes. This paper presents the model and results from the model for a SAW delay line device.

  17. Visualization of Surface Acoustic Waves in Thin Liquid Films

    PubMed Central

    Rambach, R. W.; Taiber, J.; Scheck, C. M. L.; Meyer, C.; Reboud, J.; Cooper, J. M.; Franke, T.

    2016-01-01

    We demonstrate that the propagation path of a surface acoustic wave (SAW), excited with an interdigitated transducer (IDT), can be visualized using a thin liquid film dispensed onto a lithium niobate (LiNbO3) substrate. The practical advantages of this visualization method are its rapid and simple implementation, with many potential applications including in characterising acoustic pumping within microfluidic channels. It also enables low-cost characterisation of IDT designs thereby allowing the determination of anisotropy and orientation of the piezoelectric substrate without the requirement for sophisticated and expensive equipment. Here, we show that the optical visibility of the sound path critically depends on the physical properties of the liquid film and identify heptane and methanol as most contrast rich solvents for visualization of SAW. We also provide a detailed theoretical description of this effect. PMID:26917490

  18. Acoustoelectric effects in reflection of leaky-wave-radiated bulk acoustic waves from piezoelectric crystal-conductive liquid interface.

    PubMed

    Rimeika, Romualdas; Čiplys, Daumantas; Jonkus, Vytautas; Shur, Michael

    2016-01-01

    The leaky surface acoustic wave (SAW) propagating along X-axis of Y-cut lithium tantalate crystal strongly radiates energy in the form of an obliquely propagating narrow bulk acoustic wave (BAW) beam. The reflection of this beam from the crystal-liquid interface has been investigated. The test liquids were solutions of potassium nitrate in distilled water and of lithium chloride in isopropyl alcohol with the conductivity varied by changing the solution concentration. The strong dependences of the reflected wave amplitude and phase on the liquid conductivity were observed and explained by the acoustoelectric interaction in the wave reflection region. The novel configuration of an acoustic sensor for liquid media featuring important advantages of separate measuring and sensing surfaces and rigid structure has been proposed. The application of leaky-SAW radiated bulk waves for identification of different brands of mineral water has been demonstrated.

  19. Texture in steel plates revealed by laser ultrasonic surface acoustic waves velocity dispersion analysis.

    PubMed

    Yin, Anmin; Wang, Xiaochen; Glorieux, Christ; Yang, Quan; Dong, Feng; He, Fei; Wang, Yanlong; Sermeus, Jan; Van der Donck, Tom; Shu, Xuedao

    2017-02-24

    A photoacoustic, laser ultrasonics based approach in an Impulsive Stimulated Scattering (ISS) implementation was used to investigate the texture in polycrystalline metal plates. The angular dependence of the 'polycrystalline' surface acoustic wave (SAW) velocity measured along regions containing many grains was experimentally determined and compared with simulated results that were based on the angular dependence of the 'single grain' SAW velocity within single grains and the grain orientation distribution. The polycrystalline SAW velocities turn out to vary with texture. The SAW velocities and their angular variations for {110} texture were found to be larger than that the ones for {111} texture or the strong γ fiber texture. The SAW velocities for {001} texture were larger than for {111} texture, but with almost the same angular dependence. The results infer the feasibility to apply angular SAW angular dispersion measurements by laser ultrasonics for on-line texture monitoring.

  20. Acoustic-wave sensor for ambient monitoring of a photoresist-stripping agent

    DOEpatents

    Pfeifer, K.B.; Hoyt, A.E.; Frye, G.C.

    1998-08-18

    The acoustic-wave sensor is disclosed. The acoustic-wave sensor is designed for ambient or vapor-phase monitoring of a photoresist-stripping agent such as N-methylpyrrolidinone (NMP), ethoxyethylpropionate (EEP) or the like. The acoustic-wave sensor comprises an acoustic-wave device such as a surface-acoustic-wave (SAW) device, a flexural-plate-wave (FPW) device, an acoustic-plate-mode (APM) device, or a thickness-shear-mode (TSM) device (also termed a quartz crystal microbalance or QCM) having a sensing region on a surface thereof. The sensing region includes a sensing film for sorbing a quantity of the photoresist-stripping agent, thereby altering or shifting a frequency of oscillation of an acoustic wave propagating through the sensing region for indicating an ambient concentration of the agent. According to preferred embodiments of the invention, the acoustic-wave device is a SAW device; and the sensing film comprises poly(vinylacetate), poly(N-vinylpyrrolidinone), or poly(vinylphenol). 3 figs.

  1. Acoustic-wave sensor for ambient monitoring of a photoresist-stripping agent

    DOEpatents

    Pfeifer, Kent B.; Hoyt, Andrea E.; Frye, Gregory C.

    1998-01-01

    The acoustic-wave sensor. The acoustic-wave sensor is designed for ambient or vapor-phase monitoring of a photoresist-stripping agent such as N-methylpyrrolidinone (NMP), ethoxyethylpropionate (EEP) or the like. The acoustic-wave sensor comprises an acoustic-wave device such as a surface-acoustic-wave (SAW) device, a flexural-plate-wave (FPW) device, an acoustic-plate-mode (APM) device, or a thickness-shear-mode (TSM) device (also termed a quartz crystal microbalance or QCM) having a sensing region on a surface thereof. The sensing region includes a sensing film for sorbing a quantity of the photoresist-stripping agent, thereby altering or shifting a frequency of oscillation of an acoustic wave propagating through the sensing region for indicating an ambient concentration of the agent. According to preferred embodiments of the invention, the acoustic-wave device is a SAW device; and the sensing film comprises poly(vinylacetate), poly(N-vinylpyrrolidinone), or poly(vinylphenol).

  2. Sensitivity comparisons of layered Rayleigh wave and Love wave acoustic devices

    NASA Astrophysics Data System (ADS)

    Pedrick, Michael K.; Tittmann, Bernhard R.

    2007-04-01

    Due to their high sensitivity, layered Surface Acoustic Wave (SAW) devices are ideal for various film characterization and sensor applications. Two prominent wave types realized in these devices are Rayleigh waves consisting of coupled Shear Vertical and Longitudinal displacements and Love waves consisting of Shear Horizontal displacements. Theoretical calculations of sensitivity of SAW devices to pertubations in wave propagation are limited to idealized scenarios. Derivations of sensitivity to mass change in an overlayer are often based on the effect of rigid body motion of the overlayer on the propagation of one of the aforementioned wave types. These devices often utilize polymer overlayers for enhanced sensitivity. The low moduli of such overlayers are not sufficiently stiff to accommodate the rigid body motion assumption. This work presents device modeling based on the Finite Element Method. A coupled-field model allows for a complete description of device operation including displacement profiles, frequency, wave velocity, and insertion loss through the inclusion of transmitting and receiving IDTs. Geometric rotations and coordinate transformations allow for the modeling of different crystal orientations in piezoelectric substrates. The generation of Rayleigh and Love Wave propagation was realized with this model by examining propagation in ST Quartz both normal to and in the direction of the X axis known to support Love Waves and Rayleigh Waves, respectively. Sensitivities of layered SAW devices to pertubations in mass, layer thickness, and mechanical property changes of a Polymethyl methacrylate (PMMA) and SU-8 overlayers were characterized and compared. Experimental validation of these models is presented.

  3. High-Temperature Surface-Acoustic-Wave Transducer

    NASA Technical Reports Server (NTRS)

    Zhao, Xiaoliang; Tittmann, Bernhard R.

    2010-01-01

    Aircraft-engine rotating equipment usually operates at high temperature and stress. Non-invasive inspection of microcracks in those components poses a challenge for the non-destructive evaluation community. A low-profile ultrasonic guided wave sensor can detect cracks in situ. The key feature of the sensor is that it should withstand high temperatures and excite strong surface wave energy to inspect surface/subsurface cracks. As far as the innovators know at the time of this reporting, there is no existing sensor that is mounted to the rotor disks for crack inspection; the most often used technology includes fluorescent penetrant inspection or eddy-current probes for disassembled part inspection. An efficient, high-temperature, low-profile surface acoustic wave transducer design has been identified and tested for nondestructive evaluation of structures or materials. The development is a Sol-Gel bismuth titanate-based surface-acoustic-wave (SAW) sensor that can generate efficient surface acoustic waves for crack inspection. The produced sensor is very thin (submillimeter), and can generate surface waves up to 540 C. Finite element analysis of the SAW transducer design was performed to predict the sensor behavior, and experimental studies confirmed the results. One major uniqueness of the Sol-Gel bismuth titanate SAW sensor is that it is easy to implement to structures of various shapes. With a spray coating process, the sensor can be applied to surfaces of large curvatures. Second, the sensor is very thin (as a coating) and has very minimal effect on airflow or rotating equipment imbalance. Third, it can withstand temperatures up to 530 C, which is very useful for engine applications where high temperature is an issue.

  4. Love wave acoustic sensor for testing in liquids

    NASA Astrophysics Data System (ADS)

    Pan, Haifeng; Zhu, Huizhong; Feng, Guanping

    2001-09-01

    Love wave is one type of the surface acoustic waves (SAWs). It is guided acoustic mode propagating in ta thin layer deposited on a substrate. Because of its advantages of high mass sensitivity, low noise level and being fit for operating in liquids, Love wave acoustic sensors have become one of the hot spots in the research of biosensor nowadays. In this paper the Love wave devices with the substrate of ST-cut quartz and the guiding layers of PMMA and fused quartz were fabricated successfully. By measuring the transfer function S21 and the insertion loss of the devices, the characteristics of the Rayleigh wave device and the Love wave devices with different guiding layers in gas phase and liquid phase were compared. It was validated that the Love wave sensor is suitable for testing in liquids but the Rayleigh wave sensor is not. What's more, SiO2 is the more proper material for the guiding layer of the Love wave device.

  5. Surface Acoustic-Wave-Induced Magnetoresistance Oscillations in a Two-Dimensional Electron Gas

    NASA Astrophysics Data System (ADS)

    Robinson, John P.; Kennett, Malcolm P.; Cooper, Nigel R.; Fal'Ko, Vladimir I.

    2004-07-01

    We study the geometrical commensurability oscillations imposed on the resistivity of 2D electrons in a perpendicular magnetic field by a propagating surface acoustic wave (SAW). We show that, for ω<ωc, this effect contains an anisotropic dynamical classical contribution increasing the resistivity and a nonequilibrium quantum contribution isotropically decreasing the resistivity, and we predict zero-resistance states associated with geometrical commensurability at large SAW amplitude.

  6. Millimeter Waves: Acoustic and Electromagnetic

    PubMed Central

    Ziskin, Marvin C.

    2012-01-01

    This article is the presentation I gave at the D'Arsonval Award Ceremony on June 14, 2011 at the Bioelectromagnetics Society Annual Meeting in Halifax, Nova Scotia. It summarizes my research activities in acoustic and electromagnetic millimeter waves over the past 47 years. My earliest research involved acoustic millimeter waves, with a special interest in diagnostic ultrasound imaging and its safety. For the last 21 years my research expanded to include electromagnetic millimeter waves, with a special interest in the mechanisms underlying millimeter wave therapy. Millimeter wave therapy has been widely used in the former Soviet Union with great reported success for many diseases, but is virtually unknown to Western physicians. I and the very capable members of my laboratory were able to demonstrate that the local exposure of skin to low intensity millimeter waves caused the release of endogenous opioids, and the transport of these agents by blood flow to all parts of the body resulted in pain relief and other beneficial effects. PMID:22926874

  7. Millimeter waves: acoustic and electromagnetic.

    PubMed

    Ziskin, Marvin C

    2013-01-01

    This article is the presentation I gave at the D'Arsonval Award Ceremony on June 14, 2011 at the Bioelectromagnetics Society Annual Meeting in Halifax, Nova Scotia. It summarizes my research activities in acoustic and electromagnetic millimeter waves over the past 47 years. My earliest research involved acoustic millimeter waves, with a special interest in diagnostic ultrasound imaging and its safety. For the last 21 years my research expanded to include electromagnetic millimeter waves, with a special interest in the mechanisms underlying millimeter wave therapy. Millimeter wave therapy has been widely used in the former Soviet Union with great reported success for many diseases, but is virtually unknown to Western physicians. I and the very capable members of my laboratory were able to demonstrate that the local exposure of skin to low intensity millimeter waves caused the release of endogenous opioids, and the transport of these agents by blood flow to all parts of the body resulted in pain relief and other beneficial effects.

  8. Strong Optomechanical Interaction in Hybrid Plasmonic-Photonic Crystal Nanocavities with Surface Acoustic Waves.

    PubMed

    Lin, Tzy-Rong; Lin, Chiang-Hsin; Hsu, Jin-Chen

    2015-09-08

    We propose dynamic modulation of a hybrid plasmonic-photonic crystal nanocavity using monochromatic coherent acoustic phonons formed by ultrahigh-frequency surface acoustic waves (SAWs) to achieve strong optomechanical interaction. The crystal nanocavity used in this study consisted of a defective photonic crystal beam coupled to a metal surface with a nanoscale air gap in between and provided hybridization of a highly confined plasmonic-photonic mode with a high quality factor and deep subwavelength mode volume. Efficient photon-phonon interaction occurs in the air gap through the SAW perturbation of the metal surface, strongly coupling the optical and acoustic frequencies. As a result, a large modulation bandwidth and optical resonance wavelength shift for the crystal nanocavity are demonstrated at telecommunication wavelengths. The proposed SAW-based modulation within the hybrid plasmonic-photonic crystal nanocavities beyond the diffraction limit provides opportunities for various applications in enhanced sound-light interaction and fast coherent acoustic control of optomechanical devices.

  9. Strong Optomechanical Interaction in Hybrid Plasmonic-Photonic Crystal Nanocavities with Surface Acoustic Waves

    PubMed Central

    Lin, Tzy-Rong; Lin, Chiang-Hsin; Hsu, Jin-Chen

    2015-01-01

    We propose dynamic modulation of a hybrid plasmonic-photonic crystal nanocavity using monochromatic coherent acoustic phonons formed by ultrahigh-frequency surface acoustic waves (SAWs) to achieve strong optomechanical interaction. The crystal nanocavity used in this study consisted of a defective photonic crystal beam coupled to a metal surface with a nanoscale air gap in between and provided hybridization of a highly confined plasmonic-photonic mode with a high quality factor and deep subwavelength mode volume. Efficient photon-phonon interaction occurs in the air gap through the SAW perturbation of the metal surface, strongly coupling the optical and acoustic frequencies. As a result, a large modulation bandwidth and optical resonance wavelength shift for the crystal nanocavity are demonstrated at telecommunication wavelengths. The proposed SAW-based modulation within the hybrid plasmonic-photonic crystal nanocavities beyond the diffraction limit provides opportunities for various applications in enhanced sound-light interaction and fast coherent acoustic control of optomechanical devices. PMID:26346448

  10. A surface acoustic wave technique for monitoring the growth behavior of small surface fatigue cracks

    SciTech Connect

    Resch, M.T.; Nelson, D.V.; Ramvsat, G.F.; Yuce, H.H.

    1985-03-01

    The theory of Kino and Auld which relates the reflection coefficient of acoustic waves from a crack to its size is summarized. A scattering model is evaluated from this theory concerning the reflection of surface acoustic waves (SAW) from a small surface fatigue crack at a frequency such that the crack depth is much smaller than the acoustic wavelength. Acoustic predictions of crack depth are compared to postfracture measurements of depth for small surface cracks in Pyrex glass, 7075-T651 aluminum, and 4340 steel. Additionally, the minimum detectable crack depth as limited by the acoustic noise level is determined for several typical aluminum and steel alloys. The utility of SAW reflection coefficient measurements for inferring crack depth, crack growth, and crack opening behavior in situ during fatigue cycling is discussed.

  11. Langasite Surface Acoustic Wave Sensors: Fabrication and Testing

    SciTech Connect

    Zheng, Peng; Greve, David W.; Oppenheim, Irving J.; Chin, Tao-Lun; Malone, Vanessa

    2012-02-01

    We report on the development of harsh-environment surface acoustic wave sensors for wired and wireless operation. Surface acoustic wave devices with an interdigitated transducer emitter and multiple reflectors were fabricated on langasite substrates. Both wired and wireless temperature sensing was demonstrated using radar-mode (pulse) detection. Temperature resolution of better than ±0.5°C was achieved between 200°C and 600°C. Oxygen sensing was achieved by depositing a layer of ZnO on the propagation path. Although the ZnO layer caused additional attenuation of the surface wave, oxygen sensing was accomplished at temperatures up to 700°C. The results indicate that langasite SAW devices are a potential solution for harsh-environment gas and temperature sensing.

  12. Reducing extrinsic damping of surface acoustic waves at gigahertz frequencies

    NASA Astrophysics Data System (ADS)

    Gelda, Dhruv; Sadhu, Jyothi; Ghossoub, Marc G.; Ertekin, Elif; Sinha, Sanjiv

    2016-04-01

    High-frequency surface acoustic waves (SAWs) in the gigahertz range can be generated using absorption from an ultrafast laser in a patterned metallic grating on a substrate. Reducing the attenuation at these frequencies can yield better sensors as well as enable them to better probe phonon and electron-phonon interactions near surfaces. It is not clear from existing experiments which mechanisms dominate damping at high frequencies. We calculate damping times of SAWs due to various mechanisms in the 1-100 GHz range to find that mechanical loading of the grating on the substrate dominates dissipation by radiating energy from the surface into the bulk. To overcome this and enable future measurements to probe intrinsic damping, we propose incorporating distributed acoustic Bragg reflectors in the experimental structure. Layers of alternating materials with contrasting acoustic impedances embedded a wavelength away from the surface serve to reflect energy back to the surface. Using numerical simulations, we show that a single Bragg reflector is sufficient to increase the energy density at the surface by more than five times. We quantify the resulting damping time to find that it is longer than the intrinsic damping time. The proposed structure can enable future measurements of intrinsic damping in SAWs at ˜100 GHz.

  13. Dual mode acoustic wave sensor for precise pressure reading

    NASA Astrophysics Data System (ADS)

    Mu, Xiaojing; Kropelnicki, Piotr; Wang, Yong; Randles, Andrew Benson; Chuan Chai, Kevin Tshun; Cai, Hong; Gu, Yuan Dong

    2014-09-01

    In this letter, a Microelectromechanical system acoustic wave sensor, which has a dual mode (lateral field exited Lamb wave mode and surface acoustic wave (SAW) mode) behavior, is presented for precious pressure change read out. Comb-like interdigital structured electrodes on top of piezoelectric material aluminium nitride (AlN) are used to generate the wave modes. The sensor membrane consists of single crystalline silicon formed by backside-etching of the bulk material of a silicon on insulator wafer having variable device thickness layer (5 μm-50 μm). With this principle, a pressure sensor has been fabricated and mounted on a pressure test package with pressure applied to the backside of the membrane within a range of 0 psi to 300 psi. The temperature coefficient of frequency was experimentally measured in the temperature range of -50 °C to 300 °C. This idea demonstrates a piezoelectric based sensor having two modes SAW/Lamb wave for direct physical parameter—pressure readout and temperature cancellation which can operate in harsh environment such as oil and gas exploration, automobile and aeronautic applications using the dual mode behavior of the sensor and differential readout at the same time.

  14. Enhanced sensitivity of surface acoustic wave-based rate sensors incorporating metallic dot arrays.

    PubMed

    Wang, Wen; Shao, Xiuting; Liu, Xinlu; Liu, Jiuling; He, Shitang

    2014-02-26

    A new surface acoustic wave (SAW)-based rate sensor pattern incorporating metallic dot arrays was developed in this paper. Two parallel SAW delay lines with a reverse direction and an operation frequency of 80 MHz on a same X-112°Y LiTaO3 wafer are fabricated as the feedback of two SAW oscillators, and mixed oscillation frequency was used to characterize the external rotation. To enhance the Coriolis force effect acting on the SAW propagation, a copper (Cu) dot array was deposited along the SAW propagation path of the SAW devices. The approach of partial-wave analysis in layered media was referred to analyze the response mechanisms of the SAW based rate sensor, resulting in determination of the optimal design parameters. To improve the frequency stability of the oscillator, the single phase unidirectional transducers (SPUDTs) and combed transducer were used to form the SAW device to minimize the insertion loss and accomplish the single mode selection, respectively. Excellent long-term (measured in hours) frequency stability of 0.1 ppm/h was obtained. Using the rate table with high precision, the performance of the developed SAW rate sensor was evaluated experimentally; satisfactory detection sensitivity (16.7 Hz∙deg∙s(-1)) and good linearity were observed.

  15. Is dust acoustic wave a new plasma acoustic mode?

    NASA Astrophysics Data System (ADS)

    Dwivedi, C. B.

    1997-09-01

    In this Brief Communication, the claim of the novelty of the dust acoustic wave in a dusty plasma within the constant dust charge model is questioned. Conceptual lacunas behind the claim have been highlighted and appropriate physical arguments have been forwarded against the claim. It is demonstrated that the so-called dust acoustic wave could better be termed as a general acoustic fluctuation response with a dominant characteristic feature of the acoustic-like mode (ALM) fluctuation response reported by Dwivedi et al. [J. Plasma Phys. 41, 219 (1989)]. It is suggested that both correct and more usable nomenclature of the ALM should be the so-called acoustic mode.

  16. SAW correlator spread spectrum receiver

    DOEpatents

    Brocato, Robert W

    2014-04-01

    A surface acoustic wave (SAW) correlator spread-spectrum (SS) receiver is disclosed which utilizes a first demodulation stage with a chip length n and a second demodulation stage with a chip length m to decode a transmitted SS signal having a code length l=n.times.m which can be very long (e.g. up to 2000 chips or more). The first demodulation stage utilizes a pair of SAW correlators which demodulate the SS signal to generate an appropriate code sequence at an intermediate frequency which can then be fed into the second demodulation stage which can be formed from another SAW correlator, or by a digital correlator. A compound SAW correlator comprising two input transducers and a single output transducer is also disclosed which can be used to form the SAW correlator SS receiver, or for use in processing long code length signals.

  17. Recent advances in microfluidic actuation and micro-object manipulation via surface acoustic waves.

    PubMed

    Destgeer, Ghulam; Sung, Hyung Jin

    2015-07-07

    The realization of microscale total analysis systems and lab-on-a-chip technologies requires efficient actuation (mixing, pumping, atomizing, nebulizing, driving, etc.) of fluids on the microscopic scale and dexterous manipulation (separation, sorting, trapping, concentration, merging, patterning, aligning, focusing, etc.) of micro-objects (cells, droplets, particles, nanotubes, etc.) in open (sessile droplets) as well as confined spaces (microchannels/chambers). These capabilities have been recently achieved using powerful acoustofluidic techniques based on high-frequency (10-1000 MHz) surface acoustic waves (SAWs). SAW-based miniaturized microfluidic devices are best known for their non-invasive properties, low costs, and ability to manipulate micro-objects in a label-free manner. The energy-efficient SAWs are also compatible with conventional microfabrication technologies. The present work critically analyses recent reports describing the use of SAWs in microfluidic actuation and micro-object manipulation. Acoustofluidic techniques may be categorized according to the use of travelling SAWs (TSAWs) or standing SAWs (SSAWs). TSAWs are used to actuate fluids and manipulate micro-objects via acoustic streaming flow (ASF) as well as acoustic radiation force (ARF). SSAWs are mainly used for micro-object manipulation and are rarely employed for microfluidic actuation. We have reviewed reports of new technological developments that have not been covered in other recent reviews. In the end, we describe the future prospects of SAW-based acoustofluidic technologies.

  18. Monolithic Thin Film SAW (Surface Acoustic Wave) Structures.

    DTIC Science & Technology

    1984-09-01

    storage " regions. The device is simple to fabricate, requiring neither pn or Schottky diode * arrays for -ignal storage. The memory function is...and is close to the value for LiNbOj Several convolvers and diode storage correlators which exploit the banidwidth advantage of the Sezawa mode have...fLUILcti of the properties~ of the interface. Surface state storage was subscquenitly replaced by more easily controlled and repeatable diode storage

  19. SAW (Surface Acoustic Wave) Resonator and Reflective Array Devices.

    DTIC Science & Technology

    1982-12-01

    T(f) + NS(f) + P(f) +F-(f) (1) where each term is defined as follows : H(f) - overall filter amplitude response T(f) = combined loss characteristic...steps required to fabricate the RAC line. In the discussion that follows , a brief review is provided on the key steps employed on the Engineering Phase...schematically in Figure 3.4) 29 INCIDENT ION BEAM TRANSATIO FiueS..ShmaiIEaneLtDo ethPoie thn 30’ - !7XTGdAETL I~ DISTANCE CALUMAT.XG4 SAJPES Figixte 3.5. Steps

  20. Toward efficient light diffraction and intensity variations by using wide bandwidth surface acoustic wave

    NASA Astrophysics Data System (ADS)

    Lee, Young Ok; Chen, Fu; Lee, Kee Keun

    2016-06-01

    We have developed acoustic-optic (AO) based display units for implementing a handheld hologram display by modulating light deflection through wide bandwidth surface acoustic wave (SAW). The developed AO device consists of a metal layer, a ZnS waveguide layer, SAW inter digital transducers (IDTs), and a screen for display. When RF power with a particular resonant frequency was applied to IDTs, SAW was radiated and interfered with confined beam propagating along ZnS waveguide layer. The AO interacted beam was deflected laterally toward a certain direction depending on Bragg diffraction condition, exited out of the waveguide layer and then directed to the viewing screen placed at a certain distance from the device to form a single pixel. The deflected angles was adjusted by modulating the center frequency of the SAW IDT (SAW grating), the RF power of SAW, and the angles between propagating light beam path along waveguide and radiating SAW. The diffraction efficiency was also characterized in terms of waveguide thickness, SAW RF input power, and aperture length. Coupling of mode (COM) modeling was fulfilled to find optimal device parameters prior to fabrication. All the parameters affecting the deflection angle and efficiency to form a pixel for a three-dimensional (3D) hologram image were characterized and then discussed.

  1. Acoustic waves in medical imaging and diagnostics.

    PubMed

    Sarvazyan, Armen P; Urban, Matthew W; Greenleaf, James F

    2013-07-01

    Up until about two decades ago acoustic imaging and ultrasound imaging were synonymous. The term ultrasonography, or its abbreviated version sonography, meant an imaging modality based on the use of ultrasonic compressional bulk waves. Beginning in the 1990s, there started to emerge numerous acoustic imaging modalities based on the use of a different mode of acoustic wave: shear waves. Imaging with these waves was shown to provide very useful and very different information about the biological tissue being examined. We discuss the physical basis for the differences between these two basic modes of acoustic waves used in medical imaging and analyze the advantages associated with shear acoustic imaging. A comprehensive analysis of the range of acoustic wavelengths, velocities and frequencies that have been used in different imaging applications is presented. We discuss the potential for future shear wave imaging applications.

  2. Measurement of Plasma Clotting Using Shear Horizontal Surface Acoustic Wave Sensor

    NASA Astrophysics Data System (ADS)

    Nagayama, Tatsuya; Kondoh, Jun; Oonishi, Tomoko; Hosokawa, Kazuya

    2013-07-01

    The monitoring of blood coagulation is important during operation. In this study, a shear horizontal surface acoustic wave (SH-SAW) sensor is applied to monitor plasma clotting. An SH-SAW sensor with a metallized surface for mechanical perturbation detection can detect plasma clotting. As plasma clotting is a gel formation reaction, the SH-SAW sensor detects viscoelastic property changes. On the other hand, an SH-SAW sensor with a free surface for electrical perturbation detection detects only the liquid mixing effect. No electrical property changes due to plasma clotting are obtained using this sensor. A planar electrochemical sensor is also used to monitor plasma clotting. In impedance spectral analysis, plasma clotting is measured. However, in the measurement of time responses, no differences between clotting and nonclotting are obtained. Therefore, the SH-SAW sensor is useful for monitoring plasma clotting.

  3. Implementation of Surface Acoustic Wave Vapor Sensor Using Complementary Metal-Oxide-Semiconductor Amplifiers

    NASA Astrophysics Data System (ADS)

    Chiu, Chia-Sung; Chang, Ching-Chun; Ku, Chia-Lin; Peng, Kang-Ming; Jeng, Erik S.; Chen, Wen-Lin; Huang, Guo-Wei; Wu, Lin-Kun

    2009-04-01

    A surface acoustic wave (SAW) vapor sensor is presented in this work. A SAW delay line oscillator on quartz substrate with the high gain complementary metal-oxide-semiconductor (CMOS) amplifier using a two-poly-two-metal (2P2M) 0.35 µm process was designed. The gain of the CMOS amplifier and its total power consumption are 20 dB and 70 mW, respectively. The achieved phase noise of this SAW oscillator is -150 dBc/Hz at 100 kHz offset. The sensing is successfully demonstrated by a thin poly(epichlorohydrin) (PECH) polymer film on a SAW oscillator with alcohol vapor. This two-in-one sensor unit includes the SAW device and the CMOS amplifier provides designers with comprehensive model for using these components for sensor circuit fabrication. Furthermore it will be promising for future chemical and biological sensing applications.

  4. High-Temperature Piezoelectric Crystals for Acoustic Wave Sensor Applications.

    PubMed

    Zu, Hongfei; Wu, Huiyan; Wang, Qing-Ming

    2016-03-01

    In this review paper, nine different types of high-temperature piezoelectric crystals and their sensor applications are overviewed. The important materials' properties of these piezoelectric crystals including dielectric constant, elastic coefficients, piezoelectric coefficients, electromechanical coupling coefficients, and mechanical quality factor are discussed in detail. The determination methods of these physical properties are also presented. Moreover, the growth methods, structures, and properties of these piezoelectric crystals are summarized and compared. Of particular interest are langasite and oxyborate crystals, which exhibit no phase transitions prior to their melting points ∼ 1500 °C and possess high electrical resistivity, piezoelectric coefficients, and mechanical quality factor at ultrahigh temperature ( ∼ 1000 °C). Finally, some research results on surface acoustic wave (SAW) and bulk acoustic wave (BAW) sensors developed using this high-temperature piezoelectric crystals are discussed.

  5. Manipulate acoustic waves by impedance matched acoustic metasurfaces

    NASA Astrophysics Data System (ADS)

    Wu, Ying; Mei, Jun; Aljahdali, Rasha

    We design a type of acoustic metasurface, which is composed of carefully designed slits in a rigid thin plate. The effective refractive indices of different slits are different but the impedances are kept the same as that of the host medium. Numerical simulations show that such a metasurface can redirect or reflect a normally incident wave at different frequencies, even though it is impedance matched to the host medium. We show that the underlying mechanisms can be understood by using the generalized Snell's law, and a unified analytic model based on mode-coupling theory. We demonstrate some simple realization of such acoustic metasurface with real materials. The principle is also extended to the design of planar acoustic lens which can focus acoustic waves. Manipulate acoustic waves by impedance matched acoustic metasurfaces.

  6. Optical Generation And Spatially Distinct Interferometric Detection Of Ultrahigh Frequency Surface Acoustic Waves

    SciTech Connect

    David H. Hurley

    2006-05-01

    Generation and interferometric detection of 22 GHz surface acoustic waves (SAWs) using two laterally separated absorption gratings on a Si substrate are presented. Optical phase sensitive detection of SAWs is demonstrated using a modified Sagnac interferometer. The reflection characteristics of the suboptical wavelength grating necessitate the use of only linear polarization. This is accomplished by employing a Faraday rotator to ensure path reversal of the reference and signal pulses. The enhanced sensitivity of the interferometer is exploited to measure the acoustic disturbance on an identical absorption grating at a distance of ~4.5 µm from the generation site.

  7. Application of acoustic surface wave technology to shuttle radar

    NASA Technical Reports Server (NTRS)

    1975-01-01

    The application of surface acoustic wave (SAW) signal processing devices in the space shuttle was explored. In order to demonstrate the functions which a SAW device might perform, a breadboard pulse compression filter (PCF) module was assembled. The PCF permits a pulse radar to operate with a large duty cycle and low peak power, a regime favorable to the use of solid state RF sources. The transducer design, strong coupling compensation, circuit model analysis, fabrication limitations, and performance evaluation of a PCF are described. The nominal value of the compression ratio is 100:1 with 10-MHz bandwidth centered at 60 MHz and 10-microsecond dispersive delay. The PCF incorporates dispersive interdigital transducers and a piezoelectric lithium niobate substrate.

  8. Surface acoustic wave vapor sensors based on resonator devices

    NASA Astrophysics Data System (ADS)

    Grate, Jay W.; Klusty, Mark

    1991-05-01

    Surface acoustic wave (SAW) devices fabricated in the resonator configuration have been used as organic vapor sensors and compared with delay line devices more commonly used. The experimentally determined mass sensitivities of 200, 300, and 400 MHz resonators and 158 MHz delay lines coated with Langmuir-Blodgett films of poly(vinyl tetradecanal) are in excellent agreement with theoretical predictions. The response of LB- and spray-coated sensors to various organic vapors were determined, and scaling laws for mass sensitivities, vapor sensitivities, and detection limits are discussed. The 200 MHz resonators provide the lowest noise levels and detection limits of all the devices examined.

  9. Mechanical back-action of a spin-wave resonance in a magnetoelastic thin film on a surface acoustic wave

    NASA Astrophysics Data System (ADS)

    Gowtham, P. G.; Labanowski, D.; Salahuddin, S.

    2016-07-01

    Surface acoustic waves (SAWs) traveling on the surface of a piezoelectric crystal can, through the magnetoelastic interaction, excite traveling spin-wave resonance in a magnetic film deposited on the substrate. This spin-wave resonance in the magnetic film creates a time-ynamic surface stress of magnetoelastic origin that acts back on the surface of the piezoelectric and modifies the SAW propagation. Unlike previous analyses that treat the excitation as a magnon-phonon polariton, here the magnetoelastic film is treated as a perturbation modifying boundary conditions on the SAW. We use acoustical perturbation theory to find closed-form expressions for the back-action surface stress and strain fields and the resultant SAW velocity shifts and attenuation. We demonstrate that the shear stres fields associated with this spin-wave back-action also generate effective surface currents on the piezoelectric both in phase and out of phase with the driving SAW potential. Characterization of these surface currents and their applications in determination of the magnetoelastic coupling are discussed. The perturbative calculation is carried out explicitly to first order (a regime corresponding to many experimental situations of current interest) and we provide a sketch of the implications of the theory at higher order.

  10. An Integrated Surface Acoustic Wave-Based Chemical Microsensor Array for Gas-Phase Chemical Analysis Microsystems

    SciTech Connect

    Casalnuovo, stephen A.; Frye-Mason, Gregory C.; Heller, Edwin J.; Hietala, Vincent M.; Kottenstette, Richard J.; Lewis, Patrick R.; Manginell, Ronald P.; Matzke, Carolyn M.

    1999-07-20

    This paper describes preliminary results in the development of an acoustic wave (SAW) microsensor array. The array is based on a novel configuration that allows for three sensors and a phase reference. Two configurations of the integrated array are discussed: a hybrid multichip-module based on a quartz SAW sensor with GaAs microelectronics and a fully monolithic GaAs-based SAW. Preliminary data are also presented for the use of the integrated SAW array in a gas-phase chemical micro system that incorporates microfabricated sample collectors and concentrators along with gas chromatography (GC) columns.

  11. Monitoring polymer properties using shear horizontal surface acoustic waves.

    PubMed

    Gallimore, Dana Y; Millard, Paul J; Pereira da Cunha, Mauricio

    2009-10-01

    Real-time, nondestructive methods for monitoring polymer film properties are increasingly important in the development and fabrication of modern polymer-containing products. Online testing of industrial polymer films during preparation and conditioning is required to minimize material and energy consumption, improve the product quality, increase the production rate, and reduce the number of product rejects. It is well-known that shear horizontal surface acoustic wave (SH-SAW) propagation is sensitive to mass changes as well as to the mechanical properties of attached materials. In this work, the SH-SAW was used to monitor polymer property changes primarily dictated by variations in the viscoelasticity. The viscoelastic properties of a negative photoresist film were monitored throughout the ultraviolet (UV) light-induced polymer cross-linking process using SH-SAW delay line devices. Changes in the polymer film mass and viscoelasticity caused by UV exposure produced variations in the phase velocity and attenuation of the SH-SAW propagating in the structure. Based on measured polymer-coated delay line scattering transmission responses (S(21)) and the measured polymer layer thickness and density, the viscoelastic constants c(44) and eta(44) were extracted. The polymer thickness was found to decrease 0.6% during UV curing, while variations in the polymer density were determined to be insignificant. Changes of 6% in c(44) and 22% in eta(44) during the cross-linking process were observed, showing the sensitivity of the SH-SAW phase velocity and attenuation to changes in the polymer film viscoelasticity. These results indicate the potential for SH-SAW devices as online monitoring sensors for polymer film processing.

  12. Simulation of surface acoustic wave motor with spherical slider.

    PubMed

    Morita, T; Kurosawa, M K; Higuchi, T

    1999-01-01

    The operation of a surface acoustic wave (SAW) motor using spherical-shaped sliders was demonstrated by Kurosawa et al. (1994). It was necessary to modify the previous simulation models for usual ultrasonic motors because of this slider shape and the high frequency vibration. A conventional ultrasonic motor has a flat contact surface slider and a hundredth driving frequency; so, the tangential motion caused by the elasticity of the slider and stator with regard to the spherical slider of the SAW motor requires further investigation. In this paper, a dynamic simulation model for the SAW motor is proposed. From the simulation result, the mechanism of the SAW motor was clarified (i.e., levitation and contact conditions were repeated during the operation). The transient response of the motor speed was simulated. The relationships between frictional factor and time constant and vibration velocity of the stator and the slider speed were understood. The detailed research regarding the elastic deformation caused by preload would be helpful to construct an exact simulation model for the next work.

  13. Spatial selective manipulation of microbubbles by tunable surface acoustic waves

    PubMed Central

    Zhou, Wei; Niu, Lili; Cai, Feiyan; Li, Fei; Wang, Chen; Huang, Xiaowei; Wang, Jingjing; Wu, Junru; Meng, Long; Zheng, Hairong

    2016-01-01

    A microfluidic device based on a pair of slant-finger interdigital transducers (SFITs) is developed to achieve a selective and flexible manipulation of microbubbles (MBs) by surface acoustic waves (SAWs). The resonance frequency of SAWs generated by the SFITs depends on the location of its parallel pathway; the particles at different locations of the SAWs' pathway can be controlled selectively by choosing the frequency of the excitation signal applied on the SFITs. By adjusting the input signal continuously, MBs can be transported along the acoustic aperture precisely. The displacement of MBs has a linear relationship with the frequency shift. The resolution of transportation is 15.19 ± 2.65 μm when the shift of input signal frequency is at a step of 10 kHz. In addition, the MBs can be controlled in a two-dimensional plane by combining variations of the frequency and the relative phase of the excitation signal applied on the SFITs simultaneously. This technology may open up the possibility of selectively and flexibly manipulating MBs using a simple one-dimensional device. PMID:27462381

  14. Bendable ZnO thin film surface acoustic wave devices on polyethylene terephthalate substrate

    SciTech Connect

    He, Xingli; Guo, Hongwei; Chen, Jinkai; Wang, Wenbo; Xuan, Weipeng; Xu, Yang E-mail: jl2@bolton.ac.uk; Luo, Jikui E-mail: jl2@bolton.ac.uk

    2014-05-26

    Bendable surface acoustic wave (SAW) devices were fabricated using high quality c-axis orientation ZnO films deposited on flexible polyethylene terephthalate substrates at 120 °C. Dual resonance modes, namely, the zero order pseudo asymmetric (A{sub 0}) and symmetric (S{sub 0}) Lamb wave modes, have been obtained from the SAW devices. The SAW devices perform well even after repeated flexion up to 2500 με for 100 times, demonstrating its suitability for flexible electronics application. The SAW devices are also highly sensitive to compressive and tensile strains, exhibiting excellent anti-strain deterioration property, thus, they are particularly suitable for sensing large strains.

  15. Development of GaAs-Based Monolithic Surface Acoustic Wave Devices for Chemical Sensing and RF Filter Applications

    SciTech Connect

    Baca, A.G.; Casalnuovo, S.A.; Drummond, T.J.; Frye, G.C.; Heller, E.J.; Hietala, V.M.; Klem, J.F.

    1998-12-24

    Since their invention in the mid-1960's, surface acoustic wave (SAW) devices have become popular for a wide variety of applications. SAW devices represent a low-cost and compact method of achieving a variety of electronic signal processing functions at high frequencies, such as RF filters for TV or mobile wireless communications [1]. SAW devices also provide a convenient platform in chemical sensing applications, achieving extremely high sensitivity to vapor phase analytes in part-per-billion concentrations [2]. Although the SAW acoustic mode can be created on virtually any crystalline substrate, the development of SAW technology has historically focused on the use of piezoelectric materials, such as various orientations of either quartz or lithium niobate, allowing the devices to be fabricated simply and inexpensively. However, the III-V compound semiconductors, and GaAs in particular, are also piezoelectric as a result of their partially covalent bonding and support the SAW acoustic mode, allowing for the convenient fabrication of SAW devices. In addition, GaAs microelectronics has, in the past decade, matured commercially in numerous RF wireless technologies. In fact, GaAs was recognized long ago as a potential candidate for the monolithic integration of SAW devices with microelectronics, to achieve compact RF signal processing functions [3]. The details of design and fabrication of SAW devices can be found in a variety of references [1].

  16. Laser photoacoustic technique for ultrasonic surface acoustic wave velocity evaluation on porcelain

    NASA Astrophysics Data System (ADS)

    Qian, K.; Tu, S. J.; Gao, L.; Xu, J.; Li, S. D.; Yu, W. C.; Liao, H. H.

    2016-10-01

    A laser photoacoustic technique has been developed to evaluate the surface acoustic wave (SAW) velocity of porcelain. A Q-switched Nd:YAG laser at 1064 nm was focused by a cylindrical lens to initiate broadband SAW impulses, which were detected by an optical fiber interferometer with high spatial resolution. Multiple near-field surface acoustic waves were observed on the sample surface at various locations along the axis perpendicular to the laser line source as the detector moved away from the source in the same increments. The frequency spectrum and dispersion curves were obtained by operating on the recorded waveforms with cross-correlation and FFT. The SAW phase velocities of the porcelain of the same source are similar while they are different from those of different sources. The marked differences of Rayleigh phase velocities in our experiment suggest that this technique has the potential for porcelain identification.

  17. The use of GPS arrays in detecting shock-acoustic waves generated during rocket launchings

    NASA Astrophysics Data System (ADS)

    Afraimovich, E. L.; Kosogorov, E. A.; Perevalova, N. P.; Plotnikov, A. V.

    2001-12-01

    This paper is concerned with the parameters of shock-acoustic waves (SAW) generated during rocket launchings. We have developed the interferometric method for determining SAW parameters (including angular characteristics of the wave vector, and the SAW phase velocity, as well as the direction towards the source) using GPS-arrays. Contrary to the conventional radio-probing techniques, the proposed method provides an estimate of SAW parameters without a priori information about the site and time of a rocket launching. The application of the method is illustrated by a case study of ionospheric effects from launchings of rockets PROTON, SOYUZ and SPACE SHUTTLE from Baikonur and Kennedy Space Center cosmodromes in 1998-2000. In spite of a difference of rocket characteristics, the ionospheric response for all launchings had the character of an /N-wave corresponding to the form of a shock wave. The SAW period /T is 270-360s, and the amplitude exceeds the standard deviation of total electron content background fluctuations in this range of periods under quiet and moderate geomagnetic conditions by factors of 2-5 as a minimum. The angle of elevation of the SAW wave vector varies from /30° to /60°, and the SAW phase velocity (900-1200m/s) approaches the sound velocity at heights of the ionospheric /F-region maximum. The position of the SAW source, inferred by neglecting refraction corrections, corresponds to the segment of the rockets path at a distance no less than 200-900km from the launch pad, and to the rocket flying altitude no less than 100km. Our data are consistent with the existing view that SAW are generated during a nearly horizontal flight of the rocket with its engine in operation in the acceleration segment of the path at 100-130km altitudes in the lower atmosphere.

  18. Modulated exponential films generated by surface acoustic waves and their role in liquid wicking and aerosolization at a pinned drop

    NASA Astrophysics Data System (ADS)

    Taller, Daniel; Go, David B.; Chang, Hsueh-Chia

    2013-05-01

    The exponentially decaying acoustic pressure of scattered surface acoustic waves (SAWs) at the contact line of a liquid film pinned to filter paper is shown to sustain a high curvature conic tip with micron-sized modulations whose dimension grows exponentially from the tip. The large negative capillary pressure in the film, necessary for offsetting the large positive acoustic pressure at the contact line, also creates significant negative hydrodynamic pressure and robust wicking action through the paper. An asymptotic analysis of this intricate pressure matching between the quasistatic conic film and bulk drop shows that the necessary SAW power to pump liquid from the filter paper and aerosolize, expressed in terms of the acoustic pressure scaled by the drop capillary pressure, grows exponentially with respect to twice the acoustic decay constant multiplied by the drop length, with a universal preexponential coefficient. Global rapid aerosolization occurs at a SAW power twice as high, beyond which the wicking rate saturates.

  19. Modulated exponential films generated by surface acoustic waves and their role in liquid wicking and aerosolization at a pinned drop.

    PubMed

    Taller, Daniel; Go, David B; Chang, Hsueh-Chia

    2013-05-01

    The exponentially decaying acoustic pressure of scattered surface acoustic waves (SAWs) at the contact line of a liquid film pinned to filter paper is shown to sustain a high curvature conic tip with micron-sized modulations whose dimension grows exponentially from the tip. The large negative capillary pressure in the film, necessary for offsetting the large positive acoustic pressure at the contact line, also creates significant negative hydrodynamic pressure and robust wicking action through the paper. An asymptotic analysis of this intricate pressure matching between the quasistatic conic film and bulk drop shows that the necessary SAW power to pump liquid from the filter paper and aerosolize, expressed in terms of the acoustic pressure scaled by the drop capillary pressure, grows exponentially with respect to twice the acoustic decay constant multiplied by the drop length, with a universal preexponential coefficient. Global rapid aerosolization occurs at a SAW power twice as high, beyond which the wicking rate saturates.

  20. Surface acoustic wave response to optical absorption by graphene composite film.

    PubMed

    Chivukula, Venkata S; Ciplys, Daumantas; Kim, Jin Ho; Rimeika, Romualdas; Xu, Jimmy M; Shur, Michael S

    2012-02-01

    Propagation of surface acoustic waves in YZ LiNbO3 overlaid with graphene flakes has been investigated and its optical response to illumination by 633-nm light from a He-Ne laser was studied. The heating of the sample surface caused by optical absorption by the graphene led to a downshift in the transmitted SAW phase caused by the wave velocity's dependence on temperature. The proposed simple model based on optothermal SAW phase modulation was found to be in good agreement with the experimental results.

  1. AlScN thin film based surface acoustic wave devices with enhanced microfluidic performance

    NASA Astrophysics Data System (ADS)

    Wang, W. B.; Fu, Y. Q.; Chen, J. J.; Xuan, W. P.; Chen, J. K.; Wang, X. Z.; Mayrhofer, P.; Duan, P. F.; Bittner, A.; Schmid, U.; Luo, J. K.

    2016-07-01

    This paper reports the characterization of scandium aluminum nitride (Al1-x Sc x N, x  =  27%) films and discusses surface acoustic wave (SAW) devices based on them. Both AlScN and AlN films were deposited on silicon by sputtering and possessed columnar microstructures with (0 0 0 2) crystal orientation. The AlScN/Si SAW devices showed improved electromechanical coupling coefficients (K 2, ~2%) compared with pure AlN films (<0.5%). The performance of the two types of devices was also investigated and compared, using acoustofluidics as an example. The AlScN/Si SAW devices achieved much lower threshold powers for the acoustic streaming and pumping of liquid droplets, and the acoustic streaming and pumping velocities were 2  ×  and 3  ×  those of the AlN/Si SAW devices, respectively. Mechanical characterization showed that the Young’s modulus and hardness of the AlN film decreased significantly when Sc was doped, and this was responsible for the decreased acoustic velocity and resonant frequency, and the increased temperature coefficient of frequency, of the AlScN SAW devices.

  2. Evaluation of annealing and double ion beam irradiation by a laser-induced and laser-detected surface acoustic wave diagnostic system

    NASA Astrophysics Data System (ADS)

    Kitazawa, Sin-iti; Wakai, Eiichi; Aoto, Kazumi

    2016-10-01

    The effects of annealing and double ion irradiation on nuclear structural materials were investigated using a novel, non-destructive, non-contact diagnostic method. A laser-induced and laser-detected surface acoustic wave (SAW) was adopted as a diagnostic system. The SAWs propagation velocity and the SAWs vibration velocity along the normal direction of the surface were measured to investigate mechanical properties of the substrates. Change of the shear modulus was detected in the annealed substrates. Non-linear effect on amplitude of the excited SAW was observed on the double ion irradiated materials. The potential of the SAW diagnostic system for assessing nuclear structural materials was demonstrated.

  3. Direct visualization of surface acoustic waves along substrates using smoke particles

    NASA Astrophysics Data System (ADS)

    Tan, Ming K.; Friend, James R.; Yeo, Leslie Y.

    2007-11-01

    Smoke particles (SPs) are used to directly visualize surface acoustic waves (SAWs) propagating on a 128°-rotated Y-cut X-propagating lithium niobate (LiNbO3) substrate. By electrically exciting a SAW device in a compartment filled with SP, the SP were found to collect along the regions where the SAW propagates on the substrate. The results of the experiments show that SPs are deposited adjacent to regions of large vibration amplitude and form a clear pattern corresponding to the surface wave profile on the substrate. Through an analysis of the SAW-induced acoustic streaming in the air adjacent to the substrate and the surface acceleration measured with a laser Doppler vibrometer, we postulate that the large transverse surface accelerations due to the SAW ejects SP from the surface and carries them aloft to relatively quiescent regions nearby via acoustic streaming. Offering finer detail than fine powders common in Chladni figures [E. Chladni, Entdeckungen über die Theorie des Klanges (Weidmanns, Erben und Reich, Leipzig, Germany, 1787)] the approach is an inexpensive and a quick counterpart to laser interferometric techniques, presenting a means to explore the controversial phenomena of particle agglomeration on surfaces.

  4. Excitation and propagation of shear-horizontal-type surface and bulk acoustic waves.

    PubMed

    Hashimoto, K Y; Yamaguchi, M

    2001-09-01

    This paper reviews the basic properties of shear-horizontal (SH)-type surface acoustic waves (SAWs) and bulk acoustic waves (BAWs). As one of the simplest cases, the structure supporting Bleustein-Gulyaev-Shimizu waves is considered, and their excitation and propagation are discussed from various view points. First, the formalism based on the complex integral theory is presented, where the surface is assumed to be covered with an infinitesimally thin metallic film, and it is shown how the excitation and propagation of SH-type waves are affected by the surface perturbation. Then, the analysis is extended to a periodic grating structure, and the behavior of SH-type SAWs under the grating structure is discussed. Finally, the origin of the leaky nature is explained.

  5. Acoustic wave science realized by metamaterials.

    PubMed

    Lee, Dongwoo; Nguyen, Duc Minh; Rho, Junsuk

    2017-01-01

    Artificially structured materials with unit cells at sub-wavelength scale, known as metamaterials, have been widely used to precisely control and manipulate waves thanks to their unconventional properties which cannot be found in nature. In fact, the field of acoustic metamaterials has been much developed over the past 15 years and still keeps developing. Here, we present a topical review of metamaterials in acoustic wave science. Particular attention is given to fundamental principles of acoustic metamaterials for realizing the extraordinary acoustic properties such as negative, near-zero and approaching-infinity parameters. Realization of acoustic cloaking phenomenon which is invisible from incident sound waves is also introduced by various approaches. Finally, acoustic lenses are discussed not only for sub-diffraction imaging but also for applications based on gradient index (GRIN) lens.

  6. Mass sensitivity analysis and designing of surface acoustic wave resonators for chemical sensors

    NASA Astrophysics Data System (ADS)

    Kshetrimayum, Roshan; Yadava, R. D. S.; Tandon, R. P.

    2009-05-01

    The sensitivity of surface acoustic wave (SAW) chemical sensors depends on several factors such as the frequency and phase point of SAW device operation, sensitivity of the SAW velocity to surface mass loading, sensitivity of the SAW oscillator resonance to the loop phase shift, film thickness and oscillator electronics. This paper analyzes the influence of the phase point of operation in SAW oscillator sensors based on two-port resonator devices. It is found that the mass sensitivity will be enhanced if the SAW device has a nonlinear dependence on the frequency (delay ~ frequency-1). This requires the device to generate and operate in a ωτg(ω) = const region in the device passband, where ω denotes the angular frequency of oscillation and τg(ω) denotes the phase slope of the SAW resonator device. A SAW coupled resonator filter (CRF) that take advantage of mode coupling is considered in realizing such a device to help in shaping the phase transfer characteristics of a high mass sensitivity sensor. The device design and simulation results are presented within the coupling-of-modes formalism.

  7. Is dust acoustic wave a new plasma acoustic mode?

    SciTech Connect

    Dwivedi, C.B.

    1997-09-01

    In this Brief Communication, the claim of the novelty of the dust acoustic wave in a dusty plasma within the constant dust charge model is questioned. Conceptual lacunas behind the claim have been highlighted and appropriate physical arguments have been forwarded against the claim. It is demonstrated that the so-called dust acoustic wave could better be termed as a general acoustic fluctuation response with a dominant characteristic feature of the acoustic-like mode (ALM) fluctuation response reported by Dwivedi {ital et al.} [J. Plasma Phys. {bold 41}, 219 (1989)]. It is suggested that both correct and more usable nomenclature of the ALM should be the so-called acoustic mode. {copyright} {ital 1997 American Institute of Physics.}

  8. Microwave Surface Acoustic Wave Materials.

    DTIC Science & Technology

    1980-02-01

    can exist 12 ’ 13 in a quartz-like or berlinite structure, a cristobalite structure and a tridymite structure. For many materials, these structural... preparation and fabrication problems are more involved in these structures. Due to the fact that experi- mentally and theoretically proven single crystal...layered structures for SAW devices. 91 L 15. Crystal Preparation on’Berlinite for SAW Applications U Date - August 2, 1977 Place- Mann Laboratories

  9. Nonlinear hydrodynamic effects induced by Rayleigh surface acoustic wave in sessile droplets.

    PubMed

    Alghane, M; Chen, B X; Fu, Y Q; Li, Y; Desmulliez, M P Y; Mohammed, M I; Walton, A J

    2012-11-01

    We report an experimental and numerical characterization of three-dimensional acoustic streaming behavior in small droplets of volumes (1-30 μl) induced by surface acoustic wave (SAW). We provide a quantitative evidence of the existence of strong nonlinear nature of the flow inertia in this SAW-driven flow over a range of the newly defined acoustic parameter F{NA}=Fλ/(σ/R_{d})≥0.01, which is a measure of the strength of the acoustic force to surface tension, where F is the acoustic body force, λ is the SAW wavelength, σ is the surface tension, and R{d} is the droplet radius. In contrast to the widely used Stokes model of acoustic streaming, which generally ignores such a nonlinearity, we identify that the full Navier-Stokes equation must be applied to avoid errors up to 93% between the computed streaming velocities and those from experiments as in the nonlinear case. We suggest that the Stokes model is valid only for very small acoustic power of ≤1 μW (F{NA}<0.002). Furthermore, we demonstrate that the increase of F{NA} above 0.45 induces not only internal streaming, but also the deformation of droplets.

  10. Surface acoustic wave dust deposition monitor

    DOEpatents

    Fasching, G.E.; Smith, N.S. Jr.

    1988-02-12

    A system is disclosed for using the attenuation of surface acoustic waves to monitor real time dust deposition rates on surfaces. The system includes a signal generator, a tone-burst generator/amplifier connected to a transmitting transducer for converting electrical signals into acoustic waves. These waves are transmitted through a path defining means adjacent to a layer of dust and then, in turn, transmitted to a receiving transducer for changing the attenuated acoustic wave to electrical signals. The signals representing the attenuated acoustic waves may be amplified and used in a means for analyzing the output signals to produce an output indicative of the dust deposition rates and/or values of dust in the layer. 8 figs.

  11. Shear waves in acoustic anisotropic media

    SciTech Connect

    Grechka, Vladimir; Zhang, Linbin; Rector, James W.

    2003-01-02

    Acoustic transversely isotropic (TI) media are defined by artificially setting the shear-wave velocity in the direction of symmetry axis, VS0, to zero. Contrary to conventional wisdom that equating VS0 = 0 eliminates shear waves, we demonstrate their presence and examine their properties. Specifically, we show that SV-waves generally have finite nonzero phase and group velocities in acoustic TI media. In fact, these waves have been observed in full waveform modeling, but apparently they were not understood and labeled as numerical artifacts. Acoustic TI media are characterized by extreme, in some sense infinite strength of anisotropy. It makes the following unusual wave phenomena possible: (1) there are propagation directions, where the SV-ray is orthogonal to the corresponding wavefront normal, (2) the SV-wave whose ray propagates along the symmetry axis is polarized parallel to the P-wave propagating in the same direction, (3) P-wave singularities, that is, directions where P- and SV -wave phase velocities coincide might exist in acoustic TI media. We also briefly discuss some aspects of wave propagation in low-symmetry acoustic anisotropic models. Extreme anisotropy in those media creates bizarre phase- and group-velocity surfaces that might bring intellectual delight to an anisotropic guru.

  12. Layered surface acoustic wave devices for film characterization and sensor applications

    NASA Astrophysics Data System (ADS)

    Pedrick, Michael K.

    2007-05-01

    This work has introduced novel applications for Layered Surface Acoustic Wave (SAW) devices along with concepts for enhanced sensitivity via refined modeling techniques. The derivation of Love Wave and Rayleigh wave propagation pertinent to SAW substrates with thin film overlayers was explored. Novel aspects were presented for Finite Element analysis of Layered SAW sensors. This included coordinate transformations of model geometries to coincide with crystallographic orientations known to generate Surface Skimming Bulk Waves (SSBW) and various Rayleigh wave types of propagation in ST Quartz, 90° rotated ST Quartz, and 77° Y rotated Lithium Tantalate. This work has shown for the first time, FEM prediction of SSBW, Generalized SAW and High Velocity SAW waves. Rayleigh damping properties were extended to develop a Finite element model capable of predicting Layered SAW response to glass transition in a polymer film. The ability to monitor localized mechanical behavior in a PMMA film was explored with Love Waves generated by 90° rotated ST Quartz and Shear Vertical (SV)-SAWs generated by 77° Y rotated Lithium Tantalate. Similar trends were found experimentally as compared to the Finite element models. The capability of Love Wave devices for monitoring polymer film curing behavior was investigated. The ability to qualitatively assess the bond quality between film and substrate was also demonstrated based on the characteristics of the transmitted frequency response. The results of these developments have laid the ground work for developing diagnostic tools to better characterize film behavior in practical applications. Several sensor applications for Layered SAW devices were discussed. The Shear Horizontal displacement of the Love Wave device was exploited to demonstrate the capability of such a sensor for ice detection. A clear distinction between air, water, and ice loading was found with Love Waves whereas SV-SAWs were unable to distinguish between liquid and ice

  13. Detection of Volatile Organics Using a Surface Acoustic Wave Array System

    SciTech Connect

    ANDERSON, LAWRENCE F.; BARTHOLOMEW, JOHN W.; CERNOSEK, RICHARD W.; COLBURN, CHRISTOPHER W.; CROOKS, R.M.; MARTINEZ, R.F.; OSBOURN, GORDON C.; RICCO, A.J.; STATON, ALAN W.; YELTON, WILLIAM G.

    1999-10-14

    A chemical sensing system based on arrays of surface acoustic wave (SAW) delay lines has been developed for identification and quantification of volatile organic compounds (VOCs). The individual SAW chemical sensors consist of interdigital transducers patterned on the surface of an ST-cut quartz substrate to launch and detect the acoustic waves and a thin film coating in the SAW propagation path to perturb the acoustic wave velocity and attenuation during analyte sorption. A diverse set of material coatings gives the sensor arrays a degree of chemical sensitivity and selectivity. Materials examined for sensor application include the alkanethiol-based self-assembled monolayer, plasma-processed films, custom-synthesized conventional polymers, dendrimeric polymers, molecular recognition materials, electroplated metal thin films, and porous metal oxides. All of these materials target a specific chemical fi.mctionality and the enhancement of accessible film surface area. Since no one coating provides absolute analyte specificity, the array responses are further analyzed using a visual-empirical region-of-influence (VERI) pattern recognition algorithm. The chemical sensing system consists of a seven-element SAW array with accompanying drive and control electronics, sensor signal acquisition electronics, environmental vapor sampling hardware, and a notebook computer. Based on data gathered for individual sensor responses, greater than 93%-accurate identification can be achieved for any single analyte from a group of 17 VOCs and water.

  14. Measurement of cantilever vibration using impedance-loaded surface acoustic wave sensor

    NASA Astrophysics Data System (ADS)

    Oishi, Masaki; Hamashima, Hiromitsu; Kondoh, Jun

    2016-07-01

    In this study, an impedance-loaded surface acoustic wave (SAW) sensor was demonstrated to monitor the vibration frequency. Commercialized pressure sensors and a variable capacitor were chosen as external sensors, which were connected to a reflector on a SAW device. As the reflection coefficient of the reflector depended on the impedance, the echo amplitude was influenced by changes in the impedance of the external sensor. The vibration frequency of the cantilever was determined by monitoring the echo amplitude of the SAW device. Moreover, the attenuation constant of an envelope was estimated. The results of our feasibility study indicate that the impedance-loaded SAW sensor can be applied as a detector for structural health monitoring.

  15. Single-drop liquid phase microextraction accelerated by surface acoustic wave.

    PubMed

    Zhang, Anliang; Zha, Yan

    2013-03-01

    A single-drop liquid phase microextraction method is presented, in which surface acoustic wave (SAW) is used for accelerating extraction speed. A pair of interdigital transducers with 27.5 MHz center frequency is fabricated on a 128° yx-LiNbO3 substrate. A radio frequency signal is applied to one of interdigital transducers to excite SAW. Plastic straw is filled with PDMS, leaving 1 mL for holding sample solution. Plastic straw with sample solution droplet is then dipping into extractant, into which SAW is radiated. Mass transportation from sample solution to extractant drop is accelerated due to acoustic streaming, and extraction time is decreased. An ionic liquid and an acid green-25 solution are used for extraction experiments. Results show that the extraction process is almost finished within 2 min, and extraction speed is increased with radio frequency signal power.

  16. Experimental manipulation of magnetic states of magnetostrictive nanomagnets using surface acoustic waves

    NASA Astrophysics Data System (ADS)

    Sampath, Vimal; Bhattacharya, Dhritiman; D'Souza, Noel; Bandyopadhyay, Supriyo; Atulasimha, Jayasimha

    The use of Surface Acoustic Waves (SAW) to assist magnetization switching in magnetostrictive nanomagnets has been theoretically studied and SAW-induced magnetization rotation in micron size magnets has been experimentally demonstrated. We report recent experiments on manipulation of magnetic states of Co nanoscale magnets shaped like elliptical disks (~300 nm major axis, 240 nm minor axis and 10 nm thickness) delineated on bulk 128 Y-cut lithium niobate using SAW. Specifically, isolated nanomagnets that are initially in single domain states with magnetization pointing along the major axis of the ellipse are driven into a vortex state by SAW waves. However, SAW waves can trigger complete magnetization reversal in nanomagnets of moderate shape anisotropy that are dipole coupled to a highly shape anisotropic neighboring nanomagnet. The authors acknowledge the use of high voltage and high frequency pulse generator from Prof. Umit Ozgur's lab and the help of Prof. Gary Atkinson in fabrication of the IDTs for generating the SAW. We acknowledge SHF-Small CCF-1216614 and CAREER CCF-1253370 grants; and use of CNST Nanofab facility at NIST, Gaithersburg.

  17. Microfabricated bulk wave acoustic bandgap device

    DOEpatents

    Olsson, Roy H.; El-Kady, Ihab F.; McCormick, Frederick; Fleming, James G.; Fleming, Carol

    2010-06-08

    A microfabricated bulk wave acoustic bandgap device comprises a periodic two-dimensional array of scatterers embedded within the matrix material membrane, wherein the scatterer material has a density and/or elastic constant that is different than the matrix material and wherein the periodicity of the array causes destructive interference of the acoustic wave within an acoustic bandgap. The membrane can be suspended above a substrate by an air or vacuum gap to provide acoustic isolation from the substrate. The device can be fabricated using microelectromechanical systems (MEMS) technologies. Such microfabricated bulk wave phononic bandgap devices are useful for acoustic isolation in the ultrasonic, VHF, or UHF regime (i.e., frequencies of order 1 MHz to 10 GHz and higher, and lattice constants of order 100 .mu.m or less).

  18. Microfabricated bulk wave acoustic bandgap device

    DOEpatents

    Olsson, Roy H.; El-Kady, Ihab F.; McCormick, Frederick; Fleming, James G.; Fleming, legal representative, Carol

    2010-11-23

    A microfabricated bulk wave acoustic bandgap device comprises a periodic two-dimensional array of scatterers embedded within the matrix material membrane, wherein the scatterer material has a density and/or elastic constant that is different than the matrix material and wherein the periodicity of the array causes destructive interference of the acoustic wave within an acoustic bandgap. The membrane can be suspended above a substrate by an air or vacuum gap to provide acoustic isolation from the substrate. The device can be fabricated using microelectromechanical systems (MEMS) technologies. Such microfabricated bulk wave phononic bandgap devices are useful for acoustic isolation in the ultrasonic, VHF, or UHF regime (i.e., frequencies of order 1 MHz to 10 GHz and higher, and lattice constants of order 100 .mu.m or less).

  19. Nonreciprocity of spin waves in magnonic crystals created by surface acoustic waves in structures with yttrium iron garnet

    NASA Astrophysics Data System (ADS)

    Kryshtal, R. G.; Medved, A. V.

    2015-12-01

    Experimental results of investigations of nonreciprocity for surface magnetostatic spin waves (SMSW) in the magnonic crystal created by surface acoustic waves (SAW) in yttrium iron garnet films on a gallium gadolinium garnet substrate as without metallization and with aluminum films with different electrical conductivities (thicknesses) are presented. In structures without metallization, the frequency of magnonic gaps is dependent on mutual directions of propagation of the SAW and SMSW, showing nonreciprocal properties for SMSW in SAW - magnonic crystals even with the symmetrical dispersion characteristic. In metalized SAW - magnonic crystals the shift of the magnonic band gaps frequencies at the inversion of the biasing magnetic field was observed. The frequencies of magnonic band gaps as functions of SAW frequency are presented. Measured dependencies, showing the decrease of magnonic gaps frequency and the expansion of the magnonic band gap width with the decreasing of the metal film conductivity are given. Such nonreciprocal properties of the SAW - magnonic crystals are promising for signal processing in the GHz range.

  20. A New Wave of Acoustics.

    ERIC Educational Resources Information Center

    Beyer, Robert

    1981-01-01

    Surveys 50 years of acoustical studies by discussing selected topics including the ear, nonlinear representations, underwater sound, acoustical diagnostics, absorption, electrolytes, phonons, magnetic interaction, and superfluidity and the five sounds. (JN)

  1. Particle Separation inside a Sessile Droplet with Variable Contact Angle Using Surface Acoustic Waves.

    PubMed

    Destgeer, Ghulam; Jung, Jin Ho; Park, Jinsoo; Ahmed, Husnain; Sung, Hyung Jin

    2017-01-03

    A sessile droplet of water carrying polystyrene microparticles of different diameters was uniformly exposed to high frequency surface acoustic waves (SAWs) produced by an interdigitated transducer (IDT). We investigated the concentration behavior of the microparticles as the SAWs generated a strong acoustic streaming flow (ASF) inside the water droplet and exerted a direct acoustic radiation force (ARF) on the suspended particles, the magnitude of which depended upon the particle diameter. As a result of the ARF, the microparticles were concentrated according to their diameters at different positions inside the sessile droplet placed in the path of the SAW, right in front of the IDT. The microparticle concentration behavior changed as the sessile droplet contact angle with the substrate was varied by adding surfactant to the water or by gradually evaporating the water. The positions at which the smaller and larger microparticles were concentrated remained distinguishable, even at very different experimental conditions. The long-term exposure of the droplets to the SAWs was accompanied by the gradual evaporation of the carrier fluid, which dynamically changed the droplet contact angle as well as the concentration of particles. Complete evaporation of the fluid left behind several concentrated yet separated clusters of particles on the substrate surface. The effect of the droplet contact angle on particles' concentration behavior and consequent separation of particles has been uniquely studied in this SAW-based report.

  2. Diffraction correction for precision surface acoustic wave velocity measurements

    NASA Astrophysics Data System (ADS)

    Ruiz M., Alberto; Nagy, Peter B.

    2002-09-01

    Surface wave dispersion measurements can be used to nondestructively characterize shot-peened, laser shock-peened, burnished, and otherwise surface-treated specimens. In recent years, there have been numerous efforts to separate the contribution of surface roughness from those of near-surface material variations, such as residual stress, texture, and increased dislocation density. As the accuracy of the dispersion measurements was gradually increased using state-of-the-art laser-ultrasonic scanning and sophisticated digital signal processing methods, it was recognized that a perceivable dispersive effect, similar to the one found on rough shot-peened specimens, is exhibited by untreated smooth surfaces as well. This dispersion effect is on the order of 0.1%, that is significantly higher than the experimental error associated with the measurements and comparable to the expected velocity change produced by near-surface compressive residual stresses in metals below their yield point. This paper demonstrates that the cause of this apparent dispersion is the diffraction of the surface acoustic wave (SAW) as it travels over the surface of the specimen. The results suggest that a diffraction correction may be introduced to increase the accuracy of surface wave dispersion measurements. A simple diffraction correction model was developed for surface waves and this correction was subsequently validated by laser-interferometric velocity measurements on aluminum specimens. copyright 2002 Acoustical Society of America.

  3. Investigation of phononic crystals for dispersive surface acoustic wave ozone sensors

    NASA Astrophysics Data System (ADS)

    Westafer, Ryan S.

    The object of this research was to investigate dispersion in surface phononic crystals (PnCs) for application to a newly developed passive surface acoustic wave (SAW) ozone sensor. Frequency band gaps and slow sound already have been reported for PnC lattice structures. Such engineered structures are often advertised to reduce loss, increase sensitivity, and reduce device size. However, these advances have not yet been realized in the context of surface acoustic wave sensors. In early work, we computed SAW dispersion in patterned surface structures and we confirmed that our finite element computations of SAW dispersion in thin films and in one dimensional surface PnC structures agree with experimental results obtained by laser probe techniques. We analyzed the computations to guide device design in terms of sensitivity and joint spectral operating point. Next we conducted simulations and experiments to determine sensitivity and limit of detection for more conventional dispersive SAW devices and PnC sensors. Finally, we conducted extensive ozone detection trials on passive reflection mode SAW devices, using distinct components of the time dispersed response to compensate for the effect of temperature. The experimental work revealed that the devices may be used for dosimetry applications over periods of several days.

  4. Surface Acoustic Wave Monitor for Deposition and Analysis of Ultra-Thin Films

    NASA Technical Reports Server (NTRS)

    Hines, Jacqueline H. (Inventor)

    2015-01-01

    A surface acoustic wave (SAW) based thin film deposition monitor device and system for monitoring the deposition of ultra-thin films and nanomaterials and the analysis thereof is characterized by acoustic wave device embodiments that include differential delay line device designs, and which can optionally have integral reference devices fabricated on the same substrate as the sensing device, or on a separate device in thermal contact with the film monitoring/analysis device, in order to provide inherently temperature compensated measurements. These deposition monitor and analysis devices can include inherent temperature compensation, higher sensitivity to surface interactions than quartz crystal microbalance (QCM) devices, and the ability to operate at extreme temperatures.

  5. Differentiation of red wines using an electronic nose based on surface acoustic wave devices.

    PubMed

    García, M; Fernández, M J; Fontecha, J L; Lozano, J; Santos, J P; Aleixandre, M; Sayago, I; Gutiérrez, J; Horrillo, M C

    2006-02-15

    An electronic nose, utilizing the principle of surface acoustic waves (SAW), was used to differentiate among different wines of the same variety of grapes which come from the same cellar. The electronic nose is based on eight surface acoustic wave sensors, one is a reference sensor and the others are coated by different polymers by spray coating technique. Data analysis was performed by two pattern recognition methods; principal component analysis (PCA) and probabilistic neuronal network (PNN). The results showed that electronic nose was able to identify the tested wines.

  6. Multi-functional surface acoustic wave sensor for monitoring enviromental and structural condition

    NASA Astrophysics Data System (ADS)

    Furuya, Y.; Kon, T.; Okazaki, T.; Saigusa, Y.; Nomura, T.

    2006-03-01

    As a first step to develop a health monitoring system with active and embedded nondestructive evaluation devices for the machineries and structures, multi-functional SAW (surface acoustic wave) device was developed. A piezoelectric LiNbO3(x-y cut) materials were used as a SAW substrate on which IDT(20μm pitch) was produced by lithography. On the surface of a path of SAW between IDTs, environmentally active material films of shape memory Ti50Ni41Cu(at%) with non-linear hysteresis and superelastic Ti48Ni43Cu(at%) with linear deformation behavior were formed by magnetron-sputtering technique. In this study, these two kinds of shape memory alloys SMA) system were used to measure 1) loading level, 2) phase transformation and 3)stress-strain hysteresis under cyclic loading by utilizing their linearity and non-linearity deformation behaviors. Temperature and stress dependencies of SAW signal were also investigated in the non-sputtered film state. Signal amplitude and phase change of SAW were chosen to measure as the sensing parameters. As a result, temperature, stress level, phase transformation in SMA depending on temperature and mechanical damage accumulation could be measured by the proposed multi-functional SAW sensor. Moreover, the wireless SAW sensing system which has a unique feature of no supplying electric battery was constructed, and the same characteristic evaluation is confirmed in comparison with wired case.

  7. Writing magnetic patterns with surface acoustic waves

    SciTech Connect

    Li, Weiyang; Buford, Benjamin; Jander, Albrecht; Dhagat, Pallavi

    2014-05-07

    A novel patterning technique that creates magnetization patterns in a continuous magnetostrictive film with surface acoustic waves is demonstrated. Patterns of 10 μm wide stripes of alternating magnetization and a 3 μm dot of reversed magnetization are written using standing and focusing acoustic waves, respectively. The magnetization pattern is size-tunable, erasable, and rewritable by changing the magnetic field and acoustic power. This versatility, along with its solid-state implementation (no moving parts) and electronic control, renders it as a promising technique for application in magnetic recording, magnonic signal processing, magnetic particle manipulation, and spatial magneto-optical modulation.

  8. Development of a surface acoustic wave sensor for in-situ monitoring of volatile organic compounds.

    SciTech Connect

    McGrath, Lucas K.; Wright, Jerome L.; Ho, Clifford Kuofei; Rawlinson, Kim Scott; Lindgren, Eric Richard

    2003-08-01

    This paper describes the development of a surface-acoustic-wave (SAW) sensor that is designed to be operated continuously and in situ to detect volatile organic compounds. A ruggedized stainless-steel package that encases the SAW device and integrated circuit board allows the sensor to be deployed in a variety of media including air, soil, and even water. Polymers were optimized and chosen based on their response to chlorinated aliphatic hydrocarbons (e.g., trichloroethylene), which are common groundwater contaminants. Initial testing indicates that a running-average data-logging algorithm can reduce the noise and increase the sensitivity of the in-situ sensor.

  9. Determination of Surface Stress Distributions in Steel Using Laser-Generated Surface Acoustic Waves

    NASA Astrophysics Data System (ADS)

    Shi; Yifei; Ni; Chenyin; Shen; Zhonghua; Ni; Xiaowu; Lu; Jian

    2008-05-01

    High frequency surface acoustic waves (SAWs) are excited by a pulsed laser and detected by a specially designed poly(vinylidene fluoride) (PVDF) transducer to investigate surface stress distribution. Two kinds of stressed surfaces are examined experimentally. One is a steel plate elastically deformed under simple bending forces, where the surface stress varies slowly. The other is a welded steel plate for which the surface stress varies very rapidly within a small area near the welding seam. Applying a new signal processing method developed from correlation technique, the velocity distribution of the SAWs, which reflects the stress distribution, is obtained in these two samples with high resolution.

  10. Elastic Wave Propagation Mechanisms in Underwater Acoustic Environments

    DTIC Science & Technology

    2015-09-30

    Elastic wave propagation mechanisms in underwater acoustic environments Scott D. Frank Marist College Department of Mathematics Poughkeepsie...conversion from elastic propagation to acoustic propagation, and intense interface waves on underwater acoustic environments with elastic bottoms... acoustic energy in the water column. Elastic material parameters will be varied for analysis of the dissipation of water column acoustic energy

  11. Fast Response and High Sensitivity ZnO/glass Surface Acoustic Wave Humidity Sensors Using Graphene Oxide Sensing Layer

    PubMed Central

    Xuan, Weipeng; He, Mei; Meng, Nan; He, Xingli; Wang, Wenbo; Chen, Jinkai; Shi, Tianjin; Hasan, Tawfique; Xu, Zhen; Xu, Yang; Luo, J. K.

    2014-01-01

    We report ZnO/glass surface acoustic wave (SAW) humidity sensors with high sensitivity and fast response using graphene oxide sensing layer. The frequency shift of the sensors is exponentially correlated to the humidity change, induced mainly by mass loading effect rather than the complex impedance change of the sensing layer. The SAW sensors show high sensitivity at a broad humidity range from 0.5%RH to 85%RH with < 1 sec rise time. The simple design and excellent stability of our GO-based SAW humidity sensors, complemented with full humidity range measurement, highlights their potential in a wide range of applications. PMID:25425458

  12. Fast Response and High Sensitivity ZnO/glass Surface Acoustic Wave Humidity Sensors Using Graphene Oxide Sensing Layer

    NASA Astrophysics Data System (ADS)

    Xuan, Weipeng; He, Mei; Meng, Nan; He, Xingli; Wang, Wenbo; Chen, Jinkai; Shi, Tianjin; Hasan, Tawfique; Xu, Zhen; Xu, Yang; Luo, J. K.

    2014-11-01

    We report ZnO/glass surface acoustic wave (SAW) humidity sensors with high sensitivity and fast response using graphene oxide sensing layer. The frequency shift of the sensors is exponentially correlated to the humidity change, induced mainly by mass loading effect rather than the complex impedance change of the sensing layer. The SAW sensors show high sensitivity at a broad humidity range from 0.5%RH to 85%RH with < 1 sec rise time. The simple design and excellent stability of our GO-based SAW humidity sensors, complemented with full humidity range measurement, highlights their potential in a wide range of applications.

  13. Fast response and high sensitivity ZnO/glass surface acoustic wave humidity sensors using graphene oxide sensing layer.

    PubMed

    Xuan, Weipeng; He, Mei; Meng, Nan; He, Xingli; Wang, Wenbo; Chen, Jinkai; Shi, Tianjin; Hasan, Tawfique; Xu, Zhen; Xu, Yang; Luo, J K

    2014-11-26

    We report ZnO/glass surface acoustic wave (SAW) humidity sensors with high sensitivity and fast response using graphene oxide sensing layer. The frequency shift of the sensors is exponentially correlated to the humidity change, induced mainly by mass loading effect rather than the complex impedance change of the sensing layer. The SAW sensors show high sensitivity at a broad humidity range from 0.5%RH to 85%RH with < 1 sec rise time. The simple design and excellent stability of our GO-based SAW humidity sensors, complemented with full humidity range measurement, highlights their potential in a wide range of applications.

  14. Measurement of material nonlinearity using surface acoustic wave parametric interaction and laser ultrasonics.

    PubMed

    Stratoudaki, Theodosia; Ellwood, Robert; Sharples, Steve; Clark, Matthew; Somekh, Michael G; Collison, Ian J

    2011-04-01

    A dual frequency mixing technique has been developed for measuring velocity changes caused by material nonlinearity. The technique is based on the parametric interaction between two surface acoustic waves (SAWs): The low frequency pump SAW generated by a transducer and the high frequency probe SAW generated and detected using laser ultrasonics. The pump SAW stresses the material under the probe SAW. The stress (typically <5 MPa) is controlled by varying the timing between the pump and probe waves. The nonlinear interaction is measured as a phase modulation of the probe SAW and equated to a velocity change. The velocity-stress relationship is used as a measure of material nonlinearity. Experiments were conducted to observe the pump-probe interaction by changing the pump frequency and compare the nonlinear response of aluminum and fused silica. Experiments showed these two materials had opposite nonlinear responses, consistent with previously published data. The technique could be applied to life-time predictions of engineered components by measuring changes in nonlinear response caused by fatigue.

  15. Mechanism of operation and design considerations for surface acoustic wave device vapor sensors

    NASA Astrophysics Data System (ADS)

    Wohltjen, H.

    1984-04-01

    Surface acoustic wave (SAW) devices offer many attractive features for application as vapor phase chemical microsensors. This paper describes the characteristics of SAW devices and techniques by which they can be employed as vapor sensors. The perturbation of SAW amplitude and velocity by polymeric coating films was investigated both theoretically and experimentally. High sensitivity can be achieved when the device is used as the resonating element in a delay line oscillator circuit. A simple equation has been developed from theoretical considerations which offers reasonably accurate quantitative predictions of SAW Device frequency shifts when subjected to a given mass loading. In this mode the SAW device behaves in a fashion very similar to conventional bulk wave quartz crystal microbalance except that the sensitivity can be several orders of magnitude higher and the device size can be several orders of magnitude smaller. Detection of mass changes of less than 1 femtogram by a SAW device having a surface area of 0.0001 square cm. is theoretically possible.

  16. Parameterizable Library Components for SAW Devices

    NASA Technical Reports Server (NTRS)

    Wilson, William C.; Atkinson, Gary M.

    2006-01-01

    To facilitate quick fabrication of Surface Acoustic Wave (SAW) sensors we have found it necessary to develop a library of parameterizable components. This library is the first module in our strategy towards a design tool that is integrated into existing Electronic Design Automation (EDA) tools. This library is similar to the standard cell libraries found in digital design packages. The library cells allow the user to input the design parameters which automatically generate a detailed layout of the SAW component. This paper presents the results of our development of parameterizable cells for an InterDigitated Transducer (IDT), reflector, SAW delay line, and both one and two port resonators.

  17. Tunable damper for an acoustic wave guide

    DOEpatents

    Rogers, Samuel C.

    1984-01-01

    A damper for tunably damping acoustic waves in an ultrasonic waveguide is provided which may be used in a hostile environment such as a nuclear reactor. The area of the waveguide, which may be a selected size metal rod in which acoustic waves are to be damped, is wrapped, or surrounded, by a mass of stainless steel wool. The wool wrapped portion is then sandwiched between tuning plates, which may also be stainless steel, by means of clamping screws which may be adjusted to change the clamping force of the sandwiched assembly along the waveguide section. The plates are preformed along their length in a sinusoidally bent pattern with a period approximately equal to the acoustic wavelength which is to be damped. The bent pattern of the opposing plates are in phase along their length relative to their sinusoidal patterns so that as the clamping screws are tightened a bending stress is applied to the waveguide at 180.degree. intervals along the damping section to oppose the acoustic wave motions in the waveguide and provide good coupling of the wool to the guide. The damper is tuned by selectively tightening the clamping screws while monitoring the amplitude of the acoustic waves launched in the waveguide. It may be selectively tuned to damp particular acoustic wave modes (torsional or extensional, for example) and/or frequencies while allowing others to pass unattenuated.

  18. Tunable damper for an acoustic wave guide

    DOEpatents

    Rogers, S.C.

    1982-10-21

    A damper for tunably damping acoustic waves in an ultrasonic waveguide is provided which may be used in a hostile environment such as a nuclear reactor. The area of the waveguide, which may be a selected size metal rod in which acoustic waves are to be damped, is wrapped, or surrounded, by a mass of stainless steel wool. The wool wrapped portion is then sandwiched between tuning plates, which may also be stainless steel, by means of clamping screws which may be adjusted to change the clamping force of the sandwiched assembly along the waveguide section. The plates are preformed along their length in a sinusoidally bent pattern with a period approximately equal to the acoustic wavelength which is to be damped. The bent pattern of the opposing plates are in phase along their length relative to their sinusoidal patterns so that as the clamping screws are tightened a bending stress is applied to the waveguide at 180/sup 0/ intervals along the damping section to oppose the acoustic wave motions in the waveguide and provide good coupling of the wool to the guide. The damper is tuned by selectively tightening the clamping screws while monitoring the amplitude of the acoustic waves launched in the waveguide. It may be selectively tuned to damp particular acoustic wave modes (torsional or extensional, for example) and/or frequencies while allowing others to pass unattenuated.

  19. Reflection and Refraction of Acoustic Waves by a Shock Wave

    NASA Technical Reports Server (NTRS)

    Brillouin, J.

    1957-01-01

    The presence of sound waves in one or the other of the fluid regions on either side of a shock wave is made apparent, in the region under superpressure, by acoustic waves (reflected or refracted according to whether the incident waves lie in the region of superpressure or of subpressure) and by thermal waves. The characteristics of these waves are calculated for a plane, progressive, and uniform incident wave. In the case of refraction, the refracted acoustic wave can, according to the incidence, be plane, progressive, and uniform or take the form of an 'accompanying wave' which remains attached to the front of the shock while sliding parallel to it. In all cases, geometrical constructions permit determination of the kinematic characteristics of the reflected or refractive acoustic waves. The dynamic relationships show that the amplitude of the reflected wave is always less than that of the incident wave. The amplitude of the refracted wave, whatever its type, may in certain cases be greater than that of the incident wave.

  20. Strong reduction of the coercivity by a surface acoustic wave in an out-of-plane magnetized epilayer

    NASA Astrophysics Data System (ADS)

    Thevenard, L.; Camara, I. S.; Prieur, J.-Y.; Rovillain, P.; Lemaître, A.; Gourdon, C.; Duquesne, J.-Y.

    2016-04-01

    Inverse magnetostriction is the effect by which magnetization can be changed upon application of stress/strain. A strain modulation may be created electrically by exciting interdigitated transducers to generate surface acoustic waves (SAWs). Hence SAWs appear as a possible route towards induction-free undulatory magnetic data manipulation. Here we demonstrate experimentally on an out-of-plane magnetostrictive layer a reduction of the coercive field of up to 60 % by a SAW, over millimetric distances. A simple model shows that this spectacular effect can be partly explained by the periodic lowering of the strain-dependent domain nucleation energy by the SAW. This proof of concept was done on (Ga,Mn)(As,P), a magnetic semiconductor in which the out-of-plane magnetic anisotropy can be made very weak by epitaxial growth; it should guide material engineering for all-acoustic magnetization switching.

  1. Surface acoustic wave hydrogen sensor

    NASA Technical Reports Server (NTRS)

    Bhethanabotla, Venkat R. (Inventor); Bhansali, Shekhar (Inventor)

    2006-01-01

    The present invention provides a delay line SAW device fabricated on a lithium niobate substrate and coated with a bilayer of nanocrystalline or other nanomaterials such as nanoparticles or nanowires of palladiumn and metal free pthalocyanine which will respond to hydrogen gas in near real time, at low (room) temperature, without being affected by CO, O.sub.2, CH.sub.4 and other gases, in air ambient or controlled ambient, providing sensitivity to low ppm levels.

  2. Reflectance Infrared Spectroscopy on Operating Surface Acoustic Wave Chemical Sensors During Exposure to Gas-Phase Analytes

    SciTech Connect

    Hierlemann, A.; Hill, M.; Ricco, A.J.; Staton, A.W.; Thomas, R.C.

    1999-01-11

    We have developed instrumentation to enable the combination of surface acoustic wave (SAW) sensor measurements with direct, in-situ molecular spectroscopic measurements to understand the response of the SAW sensors with respect to the interfacial chemistry of surface-confined sensing films interacting with gas-phase analytes. Specifically, the instrumentation and software was developed to perform in-situ Fourier-transform infrared external-reflectance spectroscopy (FTIR-ERS) on operating SAW devices during dosing of their chemically modified surfaces with analytes. By probing the surface with IR spectroscopy during gas exposure, it is possible to understand in unprecedented detail the interaction processes between the sorptive SAW coatings and the gaseous analyte molecules. In this report, we provide details of this measurement system, and also demonstrate the utility of these combined measurements by characterizing the SAW and FTIR-ERS responses of organic thin-film sensor coatings interacting with gas-phase analytes.

  3. Acoustofluidics and whole-blood manipulation in surface acoustic wave counterflow devices.

    PubMed

    Travagliati, Marco; Shilton, Richie J; Pagliazzi, Marco; Tonazzini, Ilaria; Beltram, Fabio; Cecchini, Marco

    2014-11-04

    On-chip functional blocks for sample preprocessing are necessary elements for the implementation of fully portable micrototal analysis systems (μTAS). We demonstrate and characterize the microparticle and whole-blood manipulation capabilities of surface acoustic wave (SAW) driven counterflow micropumps. The motion of suspended cells in this system is governed by the two dominant acoustic forces associated with the scattered SAW (of wavelength λf): acoustic-radiation force and acoustic-streaming Stokesian drag force. We show that by reducing the microchannel height (h) beyond a threshold value the balance of these forces is shifted toward the acoustic-radiation force and that this yields control of two different regimes of microparticle dynamics. In the regime dominated by the acoustic radiation force (h ≲ λf), microparticles are collected in the seminodes of the partial standing sound-wave arising from reflections off microchannel walls. This enables the complete separation of plasma and corpuscular components of whole blood in periodical predetermined positions without any prior sample dilution. Conversely, in the regime dominated by acoustic streaming (h ≫ λf), the microbeads follow vortical streamlines in a pattern characterized by three different phases during microchannel filling. This makes it possible to generate a cell-concentration gradient within whole-blood samples, a behavior not previously reported in any acoustic-streaming device. By careful device design, a new class of SAW pumping devices is presented that allows the manipulation and pretreatment of whole-blood samples for portable and integrable biological chips and is compatible with hand-held battery-operated devices.

  4. SAW based systems for mobile communications satellites

    NASA Technical Reports Server (NTRS)

    Peach, R. C.; Miller, N.; Lee, M.

    1993-01-01

    Modern mobile communications satellites, such as INMARSAT 3, EMS, and ARTEMIS, use advanced onboard processing to make efficient use of the available L-band spectrum. In all of these cases, high performance surface acoustic wave (SAW) devices are used. SAW filters can provide high selectivity (100-200 kHz transition widths), combined with flat amplitude and linear phase characteristics; their simple construction and radiation hardness also makes them especially suitable for space applications. An overview of the architectures used in the above systems, describing the technologies employed, and the use of bandwidth switchable SAW filtering (BSSF) is given. The tradeoffs to be considered when specifying a SAW based system are analyzed, using both theoretical and experimental data. Empirical rules for estimating SAW filter performance are given. Achievable performance is illustrated using data from the INMARSAT 3 engineering model (EM) processors.

  5. Development of a GaAs Monolithic Surface Acoustic Wave Integrated Circuit

    SciTech Connect

    Baca, A.G.; Casalnuovo, S.C.; Drummond, T.J.; Frye, G.C.; Heller, E.J.; Hietala, V.M.; Klem, J.F.

    1999-03-08

    An oscillator technology using surface acoustic wave delay lines integrated with GaAs MESFET electronics has been developed for GaAs-based integrated microsensor applications. The oscillator consists of a two-port SAW delay line in a feedback loop with a four-stage GaAs MESFET amplifier. Oscillators with frequencies of 470, 350, and 200 MHz have been designed and fabricated. These oscillators are also promising for other RF applications.

  6. Investigation of Shallow Bulk Acoustic Waves

    DTIC Science & Technology

    1981-11-12

    with the theoretical calculation using equivalent circuit model. How- ever, the spurious bulk wave level at high frequencies is much lower than that of...effect of a metallic grating on SBAW devices on quartz. 7 A periodic metallic structure will support horizontal shear surface waves if the finger...We have extensively investigated shallow bulk acoustic waves in. terms of material aspects, transducer equivalent circuits and device dev-.iopment

  7. Surface acoustic wave sensing of VOCs in harsh chemical environments

    SciTech Connect

    Pfeifer, K.B.; Martin, S.J.; Ricco, A.J.

    1993-06-01

    The measurement of VOC concentrations in harsh chemical and physical environments is a formidable task. A surface acoustic wave (SAW) sensor has been designed for this purpose and its construction and testing are described in this paper. Included is a detailed description of the design elements specific to operation in 300{degree}C steam and HCl environments including temperature control, gas handling, and signal processing component descriptions. In addition, laboratory temperature stability was studied and a minimum detection limit was defined for operation in industrial environments. Finally, a description of field tests performed on steam reforming equipment at Synthetica Technologies Inc. of Richmond, CA is given including a report on destruction efficiency of CCl{sub 4} in the Synthetica moving bed evaporator. Design improvements based on the field tests are proposed.

  8. Surface acoustic wave coding for orthogonal frequency coded devices

    NASA Technical Reports Server (NTRS)

    Malocha, Donald (Inventor); Kozlovski, Nikolai (Inventor)

    2011-01-01

    Methods and systems for coding SAW OFC devices to mitigate code collisions in a wireless multi-tag system. Each device producing plural stepped frequencies as an OFC signal with a chip offset delay to increase code diversity. A method for assigning a different OCF to each device includes using a matrix based on the number of OFCs needed and the number chips per code, populating each matrix cell with OFC chip, and assigning the codes from the matrix to the devices. The asynchronous passive multi-tag system includes plural surface acoustic wave devices each producing a different OFC signal having the same number of chips and including a chip offset time delay, an algorithm for assigning OFCs to each device, and a transceiver to transmit an interrogation signal and receive OFC signals in response with minimal code collisions during transmission.

  9. Quantitative surface acoustic wave detection based on colloidal gold nanoparticles and their bioconjugates.

    PubMed

    Chiu, Chi-Shun; Gwo, Shangjr

    2008-05-01

    The immobilization scheme of monodispersed gold nanoparticles (10-nm diameter) on piezoelectric substrate surfaces using organosilane molecules as cross-linkers has been developed for lithium niobate (LiNbO3) and silicon oxide (SiO2)/gold-covered lithium tantalate (LiTaO3) of Rayleigh and guided shear horizontal- (guided SH) surface acoustic wave (SAW) sensors. In this study, comparative measurements of gold nanoparticle adsorption kinetics using high-resolution field-emission scanning electron microscopy and SAW sensors allow the frequency responses of SAW sensors to be quantitatively correlated with surface densities of adsorbed nanoparticles. Using this approach, gold nanoparticles are used as the "nanosized mass standards" to scale the mass loading in a wide dynamical range. Rayleigh-SAW and guided SH-SAW sensors are employed here to monitor the surface mass changes on the device surfaces in gas and liquid phases, respectively. The mass sensitivity ( approximately 20 Hz.cm2/ng) of Rayleigh-SAW device (fundamental oscillation frequency of 113.3 MHz in air) is more than 2 orders of magnitude higher than that of conventional 9-MHz quartz crystal microbalance sensors. Furthermore, in situ (aqueous solutions), real-time measurements of adsorption kinetics for both citrate-stabilized gold nanoparticles and DNA-gold nanoparticle conjugates are also demonstrated by guided SH-SAW (fundamental oscillation frequency of 121.3 MHz). By comparing frequency shifts between the adsorption cases of gold nanoparticles and DNA-gold nanoparticle conjugates, the average number of bound oligonucleotides per gold nanoparticle can also be determined. The high mass sensitivity ( approximately 6 Hz.cm2/ng) of guided SH-SAW sensors and successful detection of DNA-gold nanoparticle conjugates paves the way for real-time biosensing in liquids using nanoparticle-enhanced SAW devices.

  10. Imaging of Acoustic Waves in Sand

    SciTech Connect

    Deason, Vance Albert; Telschow, Kenneth Louis; Watson, Scott Marshall

    2003-08-01

    There is considerable interest in detecting objects such as landmines shallowly buried in loose earth or sand. Various techniques involving microwave, acoustic, thermal and magnetic sensors have been used to detect such objects. Acoustic and microwave sensors have shown promise, especially if used together. In most cases, the sensor package is scanned over an area to eventually build up an image or map of anomalies. We are proposing an alternate, acoustic method that directly provides an image of acoustic waves in sand or soil, and their interaction with buried objects. The INEEL Laser Ultrasonic Camera utilizes dynamic holography within photorefractive recording materials. This permits one to image and demodulate acoustic waves on surfaces in real time, without scanning. A video image is produced where intensity is directly and linearly proportional to surface motion. Both specular and diffusely reflecting surfaces can be accomodated and surface motion as small as 0.1 nm can be quantitatively detected. This system was used to directly image acoustic surface waves in sand as well as in solid objects. Waves as frequencies of 16 kHz were generated using modified acoustic speakers. These waves were directed through sand toward partially buried objects. The sand container was not on a vibration isolation table, but sat on the lab floor. Interaction of wavefronts with buried objects showed reflection, diffraction and interference effects that could provide clues to location and characteristics of buried objects. Although results are preliminary, success in this effort suggests that this method could be applied to detection of buried landmines or other near-surface items such as pipes and tanks.

  11. Acoustic wave filter based on periodically poled lithium niobate.

    PubMed

    Courjon, Emilie; Bassignot, Florent; Ulliac, Gwenn; Benchabane, Sarah; Ballandras, Sylvain

    2012-09-01

    Solutions for the development of compact RF passive transducers as an alternative to standard surface or bulk acoustic wave devices are receiving increasing interest. This article presents results on the development of an acoustic band-pass filter based on periodically poled ferroelectric domains in lithium niobate. The fabrication of periodically poled transducers (PPTs) operating in the range of 20 to 650 MHz has been achieved on 3-in (76.2-mm) 500-μm-thick wafers. This kind of transducer is able to excite elliptical as well as longitudinal modes, yielding phase velocities of about 3800 and 6500 ms(-1), respectively. A new type of acoustic band-pass filter is proposed, based on the use of PPTs instead of the SAWs excited by classical interdigital transducers. The design and the fabrication of such a filter are presented, as well as experimental measurements of its electrical response and transfer function. The feasibility of such a PPT-based filter is thereby demonstrated and the limitations of this method are discussed.

  12. Topological charge pump by surface acoustic waves

    NASA Astrophysics Data System (ADS)

    Yi, Zheng; Shi-Ping, Feng; Shi-Jie, Yang

    2016-06-01

    Quantized electron pumping by the surface acoustic wave across barriers created by a sequence of split metal gates is interpreted from the viewpoint of topology. The surface acoustic wave serves as a one-dimensional periodical potential whose energy spectrum possesses the Bloch band structure. The time-dependent phase plays the role of an adiabatic parameter of the Hamiltonian which induces a geometrical phase. The pumping currents are related to the Chern numbers of the filled bands below the Fermi energy. Based on this understanding, we predict a novel effect of quantized but non-monotonous current plateaus simultaneously pumped by two homodromous surface acoustic waves. Project supported by the National Natural Science Foundation of China (Grant No. 11374036) and the National Basic Research Program of China (Grant No. 2012CB821403).

  13. High-Efficiency Photovoltaic Energy Conversion using Surface Acoustic Waves in Piezoelectric Semiconductors

    NASA Astrophysics Data System (ADS)

    Yakovenko, Victor

    2010-03-01

    We propose a radically new design for photovoltaic energy conversion using surface acoustic waves (SAWs) in piezoelectric semiconductors. The periodically modulated electric field from SAW spatially separates photogenerated electrons and holes to the maxima and minima of SAW, thus preventing their recombination. The segregated electrons and holes are transported by the moving SAW to the collecting electrodes of two types, which produce dc electric output. Recent experiments [1] using SAWs in GaAs have demonstrated the photon to current conversion efficiency of 85%. These experiments were designed for photon counting, but we propose to adapt these techniques for highly efficient photovoltaic energy conversion. The advantages are that the electron-hole segregation takes place in the whole volume where SAW is present, and the electrons and holes are transported in the organized, collective manner at high speed, as opposed to random diffusion in conventional devices.[4pt] [1] S. J. Jiao, P. D. Batista, K. Biermann, R. Hey, and P. V. Santos, J. Appl. Phys. 106, 053708 (2009).

  14. Programmable SAW development :Sandia/NASA project final report.

    SciTech Connect

    Brocato, Robert Wesley

    2004-10-01

    This report describes a project to develop both fixed and programmable surface acoustic wave (SAW) correlators for use in a low power space communication network. This work was funded by NASA at Sandia National Laboratories for fiscal years 2004, 2003, and the final part of 2002. The role of Sandia was to develop the SAW correlator component, although additional work pertaining to use of the component in a system and system optimization was also done at Sandia. The potential of SAW correlator-based communication systems, the design and fabrication of SAW correlators, and general system utilization of those correlators are discussed here.

  15. Simulation Study on Semiconductor Coupled Surface Acoustic Wave Convolver through a Multi-Strip Electrodes

    NASA Astrophysics Data System (ADS)

    Hohkawa, Kohji; Suda, Takaya; Aoki, Yusuke; Kaneshiro, Chinami; Koh, Keishin

    2001-05-01

    This paper presents results of simulation study on a semiconductor coupled surface acoustic wave (SAW) convolver, in which the propagating SAW on a highly coupling coefficient piezoelectric substrate, couples with a bonded semiconductor diodes through multi-strip electrodes. We focus our study on a relatively wide band device which is the main feature of a highly efficiency device. By using a simple analysis and circuit simulator, based on the simulation program with integrated circuit emphasis (SPICE), we clarified the effect of device parameters, such as the shape of multi-strip tapping electrodes, characteristics of diode, impedance matching condition, kinds of transmission code and electro-mechanical coupling coefficient of SAW, on the device performances. We discussed the phenomenon, which cause the degradation, focusing on the frequency domain. We also clarified the essential problems of second order effect on the wide bandwidth device, which should be solved.

  16. Contactless Monitoring of Conductivity Changes in Vanadium Pentoxide Xerogel Layers Using Surface Acoustic Waves

    NASA Astrophysics Data System (ADS)

    Rimeika, Romualdas; Sereika, Raimundas; Čiplys, Daumantas; Bondarenka, Vladimiras; Sereika, Albertas; Shur, Michael

    The hydrated form of the vanadium pentoxide (V2O5 ·nH2O) deposited by the sol-gel method on the piezoelectric YZ-LiNbO3 substrate has been studied using surface acoustic waves (SAWs). Brush-deposited and spin-coated layers, differing in thickness by an order of magnitude (∼1 μm and ∼0.1 μm, respectively) were studied. The variations with time in the transmitted SAW amplitude and phase during the gel-to-xerogel transition of V2O5 ·nH2O were observed and attributed to the acoustoelectric interaction. The possibilities of using the SAWs for contactless monitoring of the layer sheet conductivity have been demonstrated.

  17. Remote vibration measurement: A wireless passive surface acoustic wave resonator fast probing strategy

    NASA Astrophysics Data System (ADS)

    Friedt, J.-M.; Droit, C.; Ballandras, S.; Alzuaga, S.; Martin, G.; Sandoz, P.

    2012-05-01

    Surface acoustic wave (SAW) resonators can advantageously operate as passive sensors which can be interrogated through a wireless link. Amongst the practical applications of such devices, structural health monitoring through stress measurement and more generally vibration characteristics of mechanical structures benefit from the ability to bury such sensors within the considered structure (wireless and battery-less). However, measurement bandwidth becomes a significant challenge when measuring wideband vibration characteristics of mechanical structures. A fast SAW resonator measurement scheme is demonstrated here. The measurement bandwidth is limited by the physical settling time of the resonator (Q/π periods), requiring only two probe pulses through a monostatic RADAR-like electronic setup to identify the sensor resonance frequency and hence stress on a resonator acting as a strain gauge. A measurement update rate of 4800 Hz using a high quality factor SAW resonator operating in the 434 MHz Industrial, Scientific and Medical band is experimentally demonstrated.

  18. Remote vibration measurement: a wireless passive surface acoustic wave resonator fast probing strategy.

    PubMed

    Friedt, J-M; Droit, C; Ballandras, S; Alzuaga, S; Martin, G; Sandoz, P

    2012-05-01

    Surface acoustic wave (SAW) resonators can advantageously operate as passive sensors which can be interrogated through a wireless link. Amongst the practical applications of such devices, structural health monitoring through stress measurement and more generally vibration characteristics of mechanical structures benefit from the ability to bury such sensors within the considered structure (wireless and battery-less). However, measurement bandwidth becomes a significant challenge when measuring wideband vibration characteristics of mechanical structures. A fast SAW resonator measurement scheme is demonstrated here. The measurement bandwidth is limited by the physical settling time of the resonator (Q/π periods), requiring only two probe pulses through a monostatic RADAR-like electronic setup to identify the sensor resonance frequency and hence stress on a resonator acting as a strain gauge. A measurement update rate of 4800 Hz using a high quality factor SAW resonator operating in the 434 MHz Industrial, Scientific and Medical band is experimentally demonstrated.

  19. Surface acoustic wave amplification by direct current-voltage supplied to graphene film

    NASA Astrophysics Data System (ADS)

    Insepov, Z.; Emelin, E.; Kononenko, O.; Roshchupkin, D. V.; Tnyshtykbayev, K. B.; Baigarin, K. A.

    2015-01-01

    Using a high-resolution X-Ray diffraction measurement method, the surface acoustic wave (SAW) propagation in a graphene film on the surface of a Ca3TaGa3Si2O14 (CTGS) piezoelectric crystal was investigated, where an external current was driven across the graphene film. Here, we show that the application of the DC field leads to a significant enhancement of the SAW magnitude and, as a result, to amplification of the diffraction satellites. Amplification of 33.2 dB/cm for the satellite +1, and of 13.8 dB/cm for the satellite +2, at 471 MHz has been observed where the external DC voltage of +10 V was applied. Amplification of SAW occurs above a DC field much smaller than that of a system using bulk semiconductor. Theoretical estimates are in reasonable agreement with our measurements and analysis of experimental data for other materials.

  20. Fast surface acoustic wave-matrix-assisted laser desorption ionization mass spectrometry of cell response from islets of Langerhans.

    PubMed

    Bllaci, Loreta; Kjellström, Sven; Eliasson, Lena; Friend, James R; Yeo, Leslie Y; Nilsson, Staffan

    2013-03-05

    A desire for higher speed and performance in molecular profiling analysis at a reduced cost is driving a trend in miniaturization and simplification of procedures. Here we report the use of a surface acoustic wave (SAW) atomizer for fast sample handling in matrix-assisted laser desorption ionization mass spectrometry (MALDI MS) peptide and protein profiling of Islets of Langerhans, for future type 2 diabetes (T2D) studies. Here the SAW atomizer was used for ultrasound (acoustic) extraction of insulin and other peptide hormones released from freshly prepared islets, stimulated directly on a membrane. A high energy propagating SAW atomizes the membrane-bound liquid into approximately 2 μm diameter droplets, rich in cell-released molecules. Besides acting as a sample carrier, the membrane provides a purification step by entrapping cell clusters and other impurities within its fibers. A new SAW-based sample-matrix deposition method for MALDI MS was developed and characterized by a strong insulin signal, and a limit of detection (LOD) lower than 100 amol was achieved. Our results support previous work reporting the SAW atomizer as a fast and inexpensive tool for ultrasound, membrane-based sample extraction. When interfaced with MALDI MS, the SAW atomizer constitutes a valuable tool for rapid cell studies. Other biomedical applications of SAW-MALDI MS are currently being developed, aiming at fast profiling of biofluids. The membrane sampling is a simplistic and noninvasive collection method of limited volume biofluids such as the gingival fluid and the tearfilm.

  1. State-of-the-art surface acoustic wave linear motor and its future applications

    PubMed

    Kurosawa

    2000-03-01

    Two merits of the surface acoustic wave (SAW) device are its high energy density and small size. However, the driving frequency is around 10 MHz or higher. In spite of the difficulties involved with high frequency, the high energy density is attractive for actuator applications. The SAW linear motor's no load speed and maximum output force were 1.1 m/s and 3.5 N using a silicon slider. The silicon slider dimensions were 4 x 4 x 0.3 mm3. We made a lot of 30 microns diameter projections on the silicon surface. The acceleration was 1000 m/s2. The SAW motor is expected to be a high speed, quick response, high resolution microactuator, and much more. High driving voltage was a problem. Our newly designed electrode proved that the driving voltage was reduced to less than 10 V to excite the traveling wave. For actual applications, the SAW device will be placed in a slider. This design is effective in terms of performance and cost. The nanotribology of the SAW motor is also an important and interesting subject.

  2. Sensitivity of surface acoustic wave devices

    NASA Astrophysics Data System (ADS)

    Filipiak, Jerzy; Zubko, Konrad

    2001-08-01

    The SAW devices are widely used as filters, delay lines, resonators and gas sensors. It is possible to use it as mechanical force. The paper describes sensitivity of acceleration sensor based on SAW using the Rayleigh wave propagation. Since characteristic of acceleration SAW sensors are largely determined by piezoelectric materials, it is very important to select substrate with required characteristics. Researches and numerical modeling based on simply sensor model include piezoelectric beam with unilateral free end. An aggregated mass is connected to the one. The dimension and aggregated mass are various. In this case a buckling stress and sensitivity are changed. Sensitivity in main and perpendicular axis are compare for three sensor based on SiO2, LiNbO3, Li2B4O7. Influences of phase velocity, electro-mechanical coupling constant and density on sensitivity are investigated. Some mechanical parameters of the substrates in dynamic work mode are researched using sensor model and Rayleigh model of vibrations without vibration damping. The model is useful because it simply determines dependencies between sensor parameters and substrate parameters. Differences between measured and evaluated quantities are less than 5 percent. Researches based on sensor modes, which fulfilled mechanical specifications similarly to aircraft navigation.

  3. Effective pulmonary delivery of an aerosolized plasmid DNA vaccine via surface acoustic wave nebulization

    PubMed Central

    2014-01-01

    Background Pulmonary-delivered gene therapy promises to mitigate vaccine safety issues and reduce the need for needles and skilled personnel to use them. While plasmid DNA (pDNA) offers a rapid route to vaccine production without side effects or reliance on cold chain storage, its delivery to the lung has proved challenging. Conventional methods, including jet and ultrasonic nebulizers, fail to deliver large biomolecules like pDNA intact due to the shear and cavitational stresses present during nebulization. Methods In vitro structural analysis followed by in vivo protein expression studies served in assessing the integrity of the pDNA subjected to surface acoustic wave (SAW) nebulisation. In vivo immunization trials were then carried out in rats using SAW nebulized pDNA (influenza A, human hemagglutinin H1N1) condensate delivered via intratracheal instillation. Finally, in vivo pulmonary vaccinations using pDNA for influenza was nebulized and delivered via a respirator to sheep. Results The SAW nebulizer was effective at generating pDNA aerosols with sizes optimal for deep lung delivery. Successful gene expression was observed in mouse lung epithelial cells, when SAW-nebulized pDNA was delivered to male Swiss mice via intratracheal instillation. Effective systemic and mucosal antibody responses were found in rats via post-nebulized, condensed fluid instillation. Significantly, we demonstrated the suitability of the SAW nebulizer to administer unprotected pDNA encoding an influenza A virus surface glycoprotein to respirated sheep via aerosolized inhalation. Conclusion Given the difficulty of inducing functional antibody responses for DNA vaccination in large animals, we report here the first instance of successful aerosolized inhalation delivery of a pDNA vaccine in a large animal model relevant to human lung development, structure, physiology, and disease, using a novel, low-power (<1 W) surface acoustic wave (SAW) hand-held nebulizer to produce droplets of p

  4. 25 years of dust acoustic waves

    NASA Astrophysics Data System (ADS)

    Merlino, Robert L.; Merlino

    2014-12-01

    The dust acoustic wave (DAW) was first discussed by P. K. Shukla in May of 1989 at the First Capri Workshop on Dusty Plasmas. In the past 25 years, the subsequent publication of the linear and nonlinear properties of the DAW (Rao, N. N., Shukla, P. K. and Yu, M. Y. 1990 Planet. Space Sci. 38, 543) has generated and sustained a large body of theoretical and experimental research that has clarified the physics of collective effects in dusty plasmas. A unique feature of the DAW is that it can be observed (literally) using laser illumination and high-speed videography, revealing details of wave-particle interactions at an unprecedented single particle level. This paper attempts to review some of the contributions and extensions of dust acoustic wave physics, as well as identify recent findings that illustrate the potential importance of this dust wave in the agglomeration of dust particles.

  5. Acoustic waves superimposed on incompressible flows

    NASA Technical Reports Server (NTRS)

    Hodge, Steve

    1990-01-01

    The use of incompressible approximations in deriving solutions to the Lighthill wave equation was investigated for problems where an analytical solution could be found. A particular model problem involves the determination of the sound field of a spherical oscillating bubble in an ideal fluid. It is found that use of incompressible boundary conditions leads to good approximations in the important region of high acoustic wave number.

  6. Broadband acoustic cloak for ultrasound waves.

    PubMed

    Zhang, Shu; Xia, Chunguang; Fang, Nicholas

    2011-01-14

    Invisibility devices based on coordinate transformation have opened up a new field of considerable interest. We present here the first practical realization of a low-loss and broadband acoustic cloak for underwater ultrasound. This metamaterial cloak is constructed with a network of acoustic circuit elements, namely, serial inductors and shunt capacitors. Our experiment clearly shows that the acoustic cloak can effectively bend the ultrasound waves around the hidden object, with reduced scattering and shadow. Because of the nonresonant nature of the building elements, this low-loss (∼6  dB/m) cylindrical cloak exhibits invisibility over a broad frequency range from 52 to 64 kHz. Furthermore, our experimental study indicates that this design approach should be scalable to different acoustic frequencies and offers the possibility for a variety of devices based on coordinate transformation.

  7. Wave Phenomena in an Acoustic Resonant Chamber

    ERIC Educational Resources Information Center

    Smith, Mary E.; And Others

    1974-01-01

    Discusses the design and operation of a high Q acoustical resonant chamber which can be used to demonstrate wave phenomena such as three-dimensional normal modes, Q values, densities of states, changes in the speed of sound, Fourier decomposition, damped harmonic oscillations, sound-absorbing properties, and perturbation and scattering problems.…

  8. Continuous micro-vortex-based nanoparticle manipulation via focused surface acoustic waves.

    PubMed

    Collins, David J; Ma, Zhichao; Han, Jongyoon; Ai, Ye

    2016-12-20

    Despite increasing demand in the manipulation of nanoscale objects for next generation biological and industrial processes, there is a lack of methods for reliable separation, concentration and purification of nanoscale objects. Acoustic methods have proven their utility in contactless manipulation of microscale objects mainly relying on the acoustic radiation effect, though the influence of acoustic streaming has typically prevented manipulation at smaller length scales. In this work, however, we explicitly take advantage of the strong acoustic streaming in the vicinity of a highly focused, high frequency surface acoustic wave (SAW) beam emanating from a series of focused 6 μm substrate wavelength interdigital transducers patterned on a piezoelectric lithium niobate substrate and actuated with a 633 MHz sinusoidal signal. This streaming field serves to focus fluid streamlines such that incoming particles interact with the acoustic field similarly regardless of their initial starting positions, and results in particle displacements that would not be possible with a travelling acoustic wave force alone. This streaming-induced manipulation of nanoscale particles is maximized with the formation of micro-vortices that extend the width of the microfluidic channel even with the imposition of a lateral flow, occurring when the streaming-induced flow velocities are an order of magnitude larger than the lateral one. We make use of this acoustic streaming to demonstrate the continuous and differential focusing of 100 nm, 300 nm and 500 nm particles.

  9. Marble Ageing Characterization by Acoustic Waves

    NASA Astrophysics Data System (ADS)

    Boudani, Mohamed El; Wilkie-Chancellier, Nicolas; Martinez, Loïc; Hébert, Ronan; Rolland, Olivier; Forst, Sébastien; Vergès-Belmin, Véronique; Serfaty, Stéphane

    In cultural heritage, statue marble characterization by acoustic waves is a well-known non-destructive method. Such investigations through the statues by time of flight method (TOF) point out sound speeds decrease with ageing. However for outdoor stored statues as the ones in the gardens of Chateau de Versailles, ageing affects mainly the surface of the Carrara marble. The present paper proposes an experimental study of the marble acoustic properties variations during accelerated laboratory ageing. The surface degradation of the marble is reproduced in laboratory for 29 mm thick marble samples by using heating/cooling thermal cycles on one face of a marble plate. Acoustic waves are generated by 1 MHz central frequency contact transducers excited by a voltage pulse placed on both sides of the plate. During the ageing and by using ad hoc transducers, the marble samples are characterized in transmission, along their volume by shear, compressional TOF measurements and along their surface by Rayleigh waves measurements. For Rayleigh waves, both TOF by transducers and laser vibrometry methods are used to detect the Rayleigh wave. The transmission measurements point out a deep decrease of the waves speeds in conjunction with a dramatic decrease of the maximum frequency transmitted. The marble acts as a low pass filter whose characteristic frequency cut decreases with ageing. This pattern occurs also for the Rayleigh wave surface measurements. The speed change in conjunction with the bandwidth translation is shown to be correlated to the material de-structuration during ageing. With a similar behavior but reversed in time, the same king of phenomena have been observed trough sol-gel materials during their structuration from liquid to solid state (Martinez, L. et all (2004). "Chirp-Z analysis for sol-gel transition monitoring". Ultrasonics, 42(1), 507-510.). A model is proposed to interpret the acoustical measurements

  10. Switchable and Tunable Ferroelectric Bulk Acoustic Wave Resonators and Filters

    NASA Astrophysics Data System (ADS)

    Saddik, George Nabih

    Ferroelectric materials such as barium titanate (BaTiO 3 or BTO), strontium titanate (SrTiO3 or STO), and their solid solution barium strontium titanate (BaxSr1-xTiO 3 or BST) have been under investigation for over 50 years. BTO, STO, and BST are high-k dielectric materials, with a field dependent permittivity and a perovskite crystal structure. At room temperature BTO is a ferroelectric with a ferroelectric to paraelectric transition temperature of about 116°C (Curie temperature), while STO has no ferroelectric phase. The formation of a solid solution between BTO and STO allows for the engineering of the Curie temperature; the Curie temperature decreses as the mole ratio of barium decreases. Extensive research went into understanding the properties of BST and developing RF circuits such as tunable capacitors, tunable matching networks, tunable filters, phase shifters and harmonic generators. BST tunable capacitors have always had anomalous resonances in the one port scattering parameter measurements, although they are very small they degrade the quality factor of the device, and research went into reducing these resonances as much as possible. The goal of this thesis is to investigate these anomalous resonances and exploit them into RF devices and circuits. Careful investigation showed that these resonances were field induced piezoelectric resonance. Piezoelectric materials such as AlN, ZnO, and PZT are used in many applications, such as resonators, and filters. Thin film bulk acoustic wave resonators (FBAR) have been in use by research and industry since the early 1980s, and in high volume production for cell phone duplexers since early 2000s. FBAR filters and duplexers have several advantages over surface acoustic wave (SAW) and ceramic devices such as high quality factors necessary for sharp filter skirts, small size, high performance, and ease of integration. There are two approaches to designing bulk acoustic wave resonators. The first is an FBAR where a

  11. Calibrated acoustic emission system records M -3.5 to M -8 events generated on a saw-cut granite sample

    USGS Publications Warehouse

    McLaskey, Gregory C.; Lockner, David A.

    2016-01-01

    Acoustic emission (AE) analyses have been used for decades for rock mechanics testing, but because AE systems are not typically calibrated, the absolute sizes of dynamic microcrack growth and other physical processes responsible for the generation of AEs are poorly constrained. We describe a calibration technique for the AE recording system as a whole (transducers + amplifiers + digitizers + sample + loading frame) that uses the impact of a 4.76-mm free-falling steel ball bearing as a reference source. We demonstrate the technique on a 76-mm diameter cylinder of westerly granite loaded in a triaxial deformation apparatus at 40 MPa confining pressure. The ball bearing is dropped inside a cavity within the sample while inside the pressure vessel. We compare this reference source to conventional AEs generated during loading of a saw-cut fault in a second granite sample. All located AEs occur on the saw-cut surface and have moment magnitudes ranging from M −5.7 down to at least M −8. Dynamic events rupturing the entire simulated fault surface (stick–slip events) have measurable stress drop and macroscopic slip and radiate seismic waves similar to those from a M −3.5 earthquake. The largest AE events that do not rupture the entire fault are M −5.7. For these events, we also estimate the corner frequency (200–300 kHz), and we assume the Brune model to estimate source dimensions of 4–6 mm. These AE sources are larger than the 0.2 mm grain size and smaller than the 76 × 152 mm fault surface.

  12. Calibrated Acoustic Emission System Records M -3.5 to M -8 Events Generated on a Saw-Cut Granite Sample

    NASA Astrophysics Data System (ADS)

    McLaskey, Gregory C.; Lockner, David A.

    2016-11-01

    Acoustic emission (AE) analyses have been used for decades for rock mechanics testing, but because AE systems are not typically calibrated, the absolute sizes of dynamic microcrack growth and other physical processes responsible for the generation of AEs are poorly constrained. We describe a calibration technique for the AE recording system as a whole (transducers + amplifiers + digitizers + sample + loading frame) that uses the impact of a 4.76-mm free-falling steel ball bearing as a reference source. We demonstrate the technique on a 76-mm diameter cylinder of westerly granite loaded in a triaxial deformation apparatus at 40 MPa confining pressure. The ball bearing is dropped inside a cavity within the sample while inside the pressure vessel. We compare this reference source to conventional AEs generated during loading of a saw-cut fault in a second granite sample. All located AEs occur on the saw-cut surface and have moment magnitudes ranging from M -5.7 down to at least M -8. Dynamic events rupturing the entire simulated fault surface (stick-slip events) have measurable stress drop and macroscopic slip and radiate seismic waves similar to those from a M -3.5 earthquake. The largest AE events that do not rupture the entire fault are M -5.7. For these events, we also estimate the corner frequency (200-300 kHz), and we assume the Brune model to estimate source dimensions of 4-6 mm. These AE sources are larger than the 0.2 mm grain size and smaller than the 76 × 152 mm fault surface.

  13. Measuring Acoustic Nonlinearity by Collinear Mixing Waves

    NASA Astrophysics Data System (ADS)

    Liu, M.; Tang, G.; Jacobs, L. J.; Qu, J.

    2011-06-01

    It is well known that the acoustic nonlinearity parameter β is correlated to fatigue damage in metallic materials. Various methods have been developed to measure β. One of the most often used methods is the harmonic generation technique, in which β is obtained by measuring the magnitude of the second order harmonic waves. An inherent weakness of this method is the difficulty in distinguishing material nonlinearity from the nonlinearity of the measurement system. In this paper, we demonstrate the possibility of using collinear mixing waves to measure β. The wave mixing method is based on the interaction between two incident waves in a nonlinear medium. Under certain conditions, such interactions generate a third wave of different frequency. This generated third wave is also called resonant wave, because its amplitude is unbounded if the medium has no attenuation. Such resonant waves are less sensitive to the nonlinearity of the measurement system, and have the potential to identify the source location of the nonlinearity. In this work, we used a longitudinal wave and a shear wave as the incident waves. The resonant shear wave is measured experimentally on samples made of aluminum and steel, respectively. Numerical simulations of the tests were also performed using a finite difference method.

  14. Shear-horizontal surface acoustic wave phononic device with high density filling material for ultra-low power sensing applications

    SciTech Connect

    Richardson, M.; Bhethanabotla, V. R.; Sankaranarayanan, S. K. R. S.

    2014-06-23

    Finite element simulations of a phononic shear-horizontal surface acoustic wave (SAW) sensor based on ST 90°-X Quartz reveal a dramatic reduction in power consumption. The phononic sensor is realized by artificially structuring the delay path to form an acoustic meta-material comprised of a periodic microcavity array incorporating high-density materials such as tantalum or tungsten. Constructive interference of the scattered and secondary reflected waves at every microcavity interface leads to acoustic energy confinement in the high-density regions translating into reduced power loss. Tantalum filled cavities show the best performance while tungsten inclusions create a phononic bandgap. Based on our simulation results, SAW devices with tantalum filled microcavities were fabricated and shown to significantly decrease insertion loss. Our findings offer encouraging prospects for designing low power, highly sensitive portable biosensors.

  15. Theoretical analysis of surface acoustic wave propagating properties of Y-cut nano lithium niobate film on silicon dioxide

    SciTech Connect

    Chen, Jing Zhang, Qiaozhen; Han, Tao; Zhou, Liu; Tang, Gongbin; Liu, Boquan; Ji, Xiaojun

    2015-08-15

    The surface acoustic wave (SAW) propagating characteristics of Y-cut nano LiNbO{sub 3} (LN) film on SiO{sub 2}/LN substrate have been theoretically calculated. The simulated results showed a shear horizontal (SH) SAW with enhanced electromechanical coupling factor K{sup 2} owing to a dimensional effect of the nanoscale LN film. However, a Rayleigh SAW and two other resonances related to thickness vibrations caused spurious responses for wideband SAW devices. These spurious waves could be fully suppressed by properly controlling structural parameters including the electrode layer height, thickness, and the Euler angle (θ) of the LN thin film. Finally, a pure SH SAW was obtained with a wide θ range, from 0° to 5° and 165° to 180°. The largest K{sup 2} achieved for the pure SH SAW was about 35.1%. The calculated results demonstrate the promising application of nano LN film to the realization of ultra-wideband SAW devices.

  16. Surface acoustic waves induced micropatterning of cells in gelatin methacryloyl (GelMA) hydrogels.

    PubMed

    Naseer, Shahid M; Manbachi, Amir; Samandari, Mohamadmahdi; Walch, Philipp; Gao, Yuan; Zhang, Yu Shrike; Davoudi, Farideh; Wang, Wesley; Abrinia, Karen; Cooper, Jonathan M; Khademhosseini, Ali; Shin, Su Ryon

    2017-02-14

    Acoustic force patterning is an emerging technology that provides a platform to control the spatial location of cells in a rapid, accurate, yet contactless manner. However, very few studies have been reported on the usage of acoustic force patterning for the rapid arrangement of biological objects, such as cells, in a three-dimensional (3D) environment. In this study, we report on a bio-acoustic force patterning technique, which uses surface acoustic waves (SAWs) for the rapid arrangement of cells within an extracellular matrix-based hydrogel such as gelatin methacryloyl (GelMA). A proof-of-principle was achieved through both simulations and experiments based on the in-house fabricated piezoelectric SAW transducers, which enabled us to explore the effects of various parameters on the performance of the built construct. The SAWs were applied in a fashion that generated standing SAWs (SSAWs) on the substrate, the energy of which subsequently was transferred into the gel, creating a rapid, and contactless alignment of the cells (<10 s, based on the experimental conditions). Following ultraviolet radiation induced photo-crosslinking of the cell encapsulated GelMA pre-polymer solution, the patterned cardiac cells readily spread after alignment in the GelMA hydrogel and demonstrated beating activity in 5-7 days. The described acoustic force assembly method can be utilized not only to control the spatial distribution of the cells inside a 3D construct, but can also preserve the viability and functionality of the patterned cells (e.g. beating rates of cardiac cells). This platform can be potentially employed in a diverse range of applications, whether it is for tissue engineering, in vitro cell studies, or creating 3D biomimetic tissue structures.

  17. Confining capillary waves to control aerosol droplet size from surface acoustic wave nebulisation

    NASA Astrophysics Data System (ADS)

    Nazarzadeh, Elijah; Reboud, Julien; Wilson, Rab; Cooper, Jonathan M.

    Aerosols play a significant role in targeted delivery of medication through inhalation of drugs in a droplet form to the lungs. Delivery and targeting efficiencies are mainly linked to the droplet size, leading to a high demand for devices that can produce aerosols with controlled sizes in the range of 1 to 5 μm. Here we focus on enabling the control of the droplet size of a liquid sample nebulised using surface acoustic wave (SAW) generated by interdigitated transducers on a piezoelectric substrate (lithium niobate). The formation of droplets was monitored through a high-speed camera (600,000 fps) and the sizes measured using laser diffraction (Spraytec, Malvern Ltd). Results show a wide droplet size distribution (between 0.8 and 400 μm), while visual observation (at fast frame rates) revealed that the large droplets (>100 μm) are ejected due to large capillary waves (80 to 300 μm) formed at the free surface of liquid due to leakage of acoustic radiation of the SAWs, as discussed in previous literature (Qi et al. Phys Fluids, 2008). To negate this effect, we show that a modulated structure, specifically with feature sizes, typically 200 μm, prevents formation of large capillary waves by reducing the degrees of freedom of the system, enabling us to obtain a mean droplet size within the optimum range for drug delivery (<10 μm). This work was supported by an EPSRC grant (EP/K027611/1) and an ERC Advanced Investigator Award (340117-Biophononics).

  18. Cloaking of the momentum in acoustic waves.

    PubMed

    Sklan, Sophia

    2010-01-01

    Through an appropriate change in variables, we find that the three-dimensional acoustic wave equation is subject to the transformation media interpretation. In particular, we determine that this interpretation can be extended beyond the pressure difference to also account for the momentum transported by the wave. The suitability of momentum transport is especially interesting as it is an example where the field of interest is not governed by a wave equation. We examine how both fields behave in the case of cloaking. Explicit consideration of the boundary conditions shows that perfect cloaking is preserved, even when the incoming momentum is nonzero at the surface of the cloak.

  19. Slippery Liquid-Infused Porous Surfaces and Droplet Transportation by Surface Acoustic Waves

    NASA Astrophysics Data System (ADS)

    Luo, J. T.; Geraldi, N. R.; Guan, J. H.; McHale, G.; Wells, G. G.; Fu, Y. Q.

    2017-01-01

    On a solid surface, a droplet of liquid will stick due to the capillary adhesion, and this causes low droplet mobility. To reduce contact line pinning, surface chemistry can be coupled to micro- and/or nanostructures to create superhydrophobic surfaces on which a droplet balls up into an almost spherical shape, thus, minimizing the contact area. Recent progress in soft matter has now led to alternative lubricant-impregnated surfaces capable of almost zero contact line pinning and high droplet mobility without causing droplets to ball up and minimize the contact area. Here we report an approach to surface-acoustic-wave- (SAW) actuated droplet transportation enabled using such a surface. These surfaces maintain the contact area required for efficient energy and momentum transfer of the wave energy into the droplet while achieving high droplet mobility and a large footprint, therefore, reducing the threshold power required to induce droplet motion. In our approach, we use a slippery layer of lubricating oil infused into a self-assembled porous hydrophobic layer, which is significantly thinner than the SAW wavelength, and avoid damping of the wave. We find a significant reduction (up to 85%) in the threshold power for droplet transportation compared to that using a conventional surface-treatment method. Moreover, unlike droplets on superhydrophobic surfaces, where interaction with the SAW induces a transition from a Cassie-Baxter state to a Wenzel state, the droplets on our liquid-impregnated surfaces remain in a mobile state after interaction with the SAW.

  20. Complex dispersion relation of surface acoustic waves at a lossy metasurface

    NASA Astrophysics Data System (ADS)

    Schwan, Logan; Geslain, Alan; Romero-García, Vicente; Groby, Jean-Philippe

    2017-01-01

    The complex dispersion relation of surface acoustic waves (SAWs) at a lossy resonant metasurface is theoretically and experimentally reported. The metasurface consists of the periodic arrangement of borehole resonators in a rigid substrate. The theoretical model relies on a boundary layer approach that provides the effective metasurface admittance governing the complex dispersion relation in the presence of viscous and thermal losses. The model is experimentally validated by measurements in the semi-anechoic chamber. The complex SAW dispersion relation is experimentally retrieved from the analysis of the spatial Laplace transform of the pressure scanned along a line at the metasurface. The geometrical spreading of the energy from the speaker is accounted for, and both the real and imaginary parts of the SAW wavenumber are obtained. The results show that the strong reduction of the SAW group velocity occurs jointly with a drastic attenuation of the wave, leading to the confinement of the field close to the source and preventing the efficient propagation of such slow-sound surface modes. The method opens perspectives to theoretically predict and experimentally characterize both the dispersion and the attenuation of surface waves at structured surfaces.

  1. Energy spectrometry of electrons ejected from dynamic quantum dots driven up a potential slope by a surface acoustic wave

    NASA Astrophysics Data System (ADS)

    Ford, Christopher; Benesh, Matthew; Son, Seok-Kyun; Kataoka, Masaya; Barnes, Crispin; McNeil, Robert; Griffiths, Jon; Jones, Geb; Farrer, Ian; Ritchie, David

    2013-03-01

    Surface acoustic waves (SAWs) in a GaAs/AlGaAs heterostructure generate an electrostatic wave which propagates at the sound velocity. This potential wave is capable of collecting electrons from a 2D electron gas (2DEG) and transporting them through a depleted channel. The SAW minima form a continuous series of dynamic quantum dots, each transporting a controllable number of electrons along the channel. The confinement of the electrons in each dot increases as the potential rises along the channel, ejecting electrons one-by-one back into the 2DEG above the Fermi energy. These electrons can travel several microns before thermalising. We measure their energy spectrum using a variable potential barrier upstream as the channel is squeezed by split gates, and correlate this with the SAW-driven current along the channel. Now at RWTH Aachen

  2. Millimeter-Wave Acoustic Transducers

    DTIC Science & Technology

    1990-04-01

    Phys . Rev. Lett . 54, 1810 ( 1985 ). 28. S.A. Akhmanov, V.V. Fadeev, R.V. Khokhlov, and O.N. Chunaev, Sov . Phys . JETP Lett . 6, 85...Acoust. Soc. Am. 66, 1801 (1979). 41 . F.P. Milliken, K.W. Schwartz and C.W. Smith, Phys . Rev. Lett . 48, 1204 (1982). 42 . T.E. Huber and H.J. Maris... Phys . Lett . 7, 264 (1965). 7. K.H. Yang, P.L. Richards, and Y.R. Shen, J. Appl. Phys . 44, 1417 (1973). 8. H.K. Wong, G.K. Wong and J.B.

  3. Development of Surface Acoustic Wave-Based Microgyroscope Utilizing Progressive Wave

    NASA Astrophysics Data System (ADS)

    Oh, Haekwan; Yang, Sangsik; Lee, Keekeun

    2010-06-01

    An 80 MHz surface acoustic wave (SAW)-based gyroscope utilizing a progressive wave was developed on a 128° YX LiNbO3 piezoelectric substrate. The sensor developed consists of two SAW oscillators in which one is used as the sensing element and has metallic dots in the cavity between input and output interdigital transducers (IDTs). The other is used as the reference element. Coupling of modes (COM) modeling was conducted to determine the optimal device parameters prior to fabrication. On the basis of the simulation results, the device was fabricated and then measured on a rate table. When the device was subjected to an angular rotation, oscillation frequency differences between the two oscillators were observed because of the Coriolis force acting on the metallic dots. Depending on the angular velocity, the difference in oscillation frequency was modulated. The obtained sensitivity was approximately 52.35 Hz deg-1 s-1 at an angular rate range of 0-1000 deg/s. Device performances at different mass weights, mass positions, and temperatures were characterized. Good thermal stability was also observed during the evaluation process.

  4. Guided shear horizontal surface acoustic wave sensors for chemical and biochemical detection in liquids.

    PubMed

    Josse, F; Bender, F; Cernose, R W

    2001-12-15

    The design and performance of guided shear horizontal surface acoustic wave (guided SH-SAW) devices on LiTaO3 substrates are investigated for high-sensitivity chemical and biochemical sensors in liquids. Despite their structural similarity to Rayleigh SAW, SH-SAWs often propagate slightly deeper within the substrate, hence preventing the implementation of high-sensitivity detectors. The device sensitivity to mass and viscoelastic loading is increased using a thin guiding layer on the device surface. Because of their relatively low shear wave velocity, various polymers including poly(methyl methacrylate) (PMMA) and cyanoethyl cellulose (cured or cross-linked) are investigated as the guiding layers to trap the acoustic energy near the sensing surface. The devices have been tested in biosensing and chemical sensing experiments. Suitable design principles for these applications are discussed with regard to wave guidance, electrical passivation of the interdigital transducers from the liquid environments, acoustic loss, and sensor signal distortion. In biosensing experiments, using near-optimal PMMA thickness of approximately 2 microm, mass sensitivity greater than 1500 Hz/(ng/mm2) is demonstrated, resulting in a minimum detection limit less than 20 pg/mm2. For chemical sensor experiments, it is found that optimal waveguide thickness must be modified to account for the chemically sensitive layer which also acts to guide the SH-SAW. A detection limit of 780 (3 x peak-to-peak noise) or 180 ppb (3 x rms noise) is estimated from the present measurements for some organic compounds in water.

  5. Extraordinary transmission of gigahertz surface acoustic waves

    PubMed Central

    Mezil, Sylvain; Chonan, Kazuki; Otsuka, Paul H.; Tomoda, Motonobu; Matsuda, Osamu; Lee, Sam H.; Wright, Oliver B.

    2016-01-01

    Extraordinary transmission of waves, i.e. a transmission superior to the amount predicted by geometrical considerations of the aperture alone, has to date only been studied in the bulk. Here we present a new class of extraordinary transmission for waves confined in two dimensions to a flat surface. By means of acoustic numerical simulations in the gigahertz range, corresponding to acoustic wavelengths λ ~ 3–50 μm, we track the transmission of plane surface acoustic wave fronts between two silicon blocks joined by a deeply subwavelength bridge of variable length with or without an attached cavity. Several resonant modes of the structure, both one- and two-dimensional in nature, lead to extraordinary acoustic transmission, in this case with transmission efficiencies, i.e. intensity enhancements, up to ~23 and ~8 in the two respective cases. We show how the cavity shape and bridge size influence the extraordinary transmission efficiency. Applications include new metamaterials and subwavelength imaging. PMID:27640998

  6. Acoustic-gravity waves, theory and application

    NASA Astrophysics Data System (ADS)

    Kadri, Usama; Farrell, William E.; Munk, Walter

    2015-04-01

    Acoustic-gravity waves (AGW) propagate in the ocean under the influence of both the compressibility of sea water and the restoring force of gravity. The gravity dependence vanishes if the wave vector is normal to the ocean surface, but becomes increasingly important as the wave vector acquires a horizontal tilt. They are excited by many sources, including non-linear surface wave interactions, disturbances of the ocean bottom (submarine earthquakes and landslides) and underwater explosions. In this introductory lecture on acoustic-gravity waves, we describe their properties, and their relation to organ pipe modes, to microseisms, and to deep ocean signatures by short surface waves. We discuss the generation of AGW by underwater earthquakes; knowledge of their behaviour with water depth can be applied for the early detection of tsunamis. We also discuss their generation by the non-linear interaction of surface gravity waves, which explains the major role they play in transforming energy from the ocean surface to the crust, as part of the microseisms phenomenon. Finally, they contribute to horizontal water transport at depth, which might affect benthic life.

  7. Study of flow induced by sine wave and saw tooth plasma actuators

    NASA Astrophysics Data System (ADS)

    Liu, Zhifeng; Wang, Lianze; Fu, Song

    2011-11-01

    The effect of plasma actuator that uses saw-tooth or sine-wave shape electrodes on boundary layer flows is experimentally investigated. The measurement results are compared with a corresponding standard configuration (conventional design using two rectangular strip electrodes)—the actuator that produces a nearly two-dimensional horizontal wall jet upon actuation. PIV measurements are used to characterize the actuators in a quiescent chamber. Operating in a steady manner, the new actuators result in the formation of streamwise and spanwise vortices. That is to say, the new actuators render the plasma actuators inducing three-dimensional variations in the shear layer, offering significant flexibility in flow control. The affected flowfield with the new actuators is significantly larger than that with the conventional linear actuators. While the conventional linear actuators affect primarily the boundary layer flow on a scale of about 1 cm above the wall, the new actuators affect the near wall region at a significantly larger scale. This new design broadens the applicability and enhances the flow control effects and it is potentially a more efficient flow control device.

  8. Surface acoustic wave regulated single photon emission from a coupled quantum dot-nanocavity system

    NASA Astrophysics Data System (ADS)

    Weiß, M.; Kapfinger, S.; Reichert, T.; Finley, J. J.; Wixforth, A.; Kaniber, M.; Krenner, H. J.

    2016-07-01

    A coupled quantum dot-nanocavity system in the weak coupling regime of cavity-quantumelectrodynamics is dynamically tuned in and out of resonance by the coherent elastic field of a fSAW ≃ 800 MHz surface acoustic wave. When the system is brought to resonance by the sound wave, light-matter interaction is strongly increased by the Purcell effect. This leads to a precisely timed single photon emission as confirmed by the second order photon correlation function, g(2). All relevant frequencies of our experiment are faithfully identified in the Fourier transform of g(2), demonstrating high fidelity regulation of the stream of single photons emitted by the system.

  9. SAW Sensor for Fastener Failure Detection

    NASA Technical Reports Server (NTRS)

    Wilson, W. C.; Rogge, M. D.; Fisher, B.; Roller, M. J.; Malocha, D. M.

    2010-01-01

    The proof of concept for using surface acoustic wave (SAW) strain sensors in the detection of aircraft fastener failures is demonstrated. SAW sensors were investigated because they have the potential for the development of passive wireless systems. The SAW devices employed four orthogonal frequency coding (OFC) spread spectrum reflectors in two banks on a high temperature piezoelectric substrate. Three SAW devices were attached to a cantilever panel with removable side stiffeners. Damage in the form of fastener failure was simulated by removal of bolts from the side stiffeners. During testing, three different force conditions were used to simulate static aircraft structural response under loads. The design of the sensor, the panel arrangement and the panel testing results are reported. The results show that the sensors successfully detected single fastener failure at distances up to 54.6 cm from the failure site under loaded conditions.

  10. Chemically sensitive interfaces on SAW devices

    SciTech Connect

    Ricco, A.J.; Martin, S.J.; Crooks, R.M.; Xu, Chuanjing; Allred, R.E.

    1993-11-01

    Using surface acoustic wave (SAW) devices, three approaches to the effective use of chemically sensitive interfaces that are not highly chemically selective have been examined: (1) molecular identification from time-resolved permeation transients; (2) using multifrequency SAW devices to determine the frequency dependence of analyte/film interactions; (3) use of an array of SAW devices bearing diverse chemically sensitive interfaces to produce a distinct response pattern for each analyte. In addition to their well-known sensitivity to mass changes (0.0035 monolayer of N{sub 2} can be measured), SAW devices respond to the mechanical and electronic properties of thin films, enhancing response information content but making a thorough understanding of the perturbation critical. Simultaneous measurement of changes in frequency and attenuation, which can provide the information necessary to determine the type of perturbation, are used as part of the above discrimination schemes.

  11. Elastic wave invariants for acoustic emission

    NASA Astrophysics Data System (ADS)

    Pardee, W. J.

    1981-07-01

    It is shown that there are four conserved properties of an elastic wave in an infinite isotropic plate: the energy, the two components of wave momentum parallel to the surface, and wave angular momentum normal to the surface. All four invariants are volume integrals of quadratic functions of the spatial (Eulerian) coordinates. The canonical energy-momentum density tensor and the orbital, spin, and total angular momentum density tensors are constructed and sufficient conditions for their conservation are demonstrated. A procedure for measuring the wave momentum of a surface wave is proposed. It is argued that these invariants are likely to be particularly useful characterizations of acoustic emission, e.g., from a growing crack. Experimental tests are proposed, and possible applications to practical monitoring problems described.

  12. Acoustic Remote Sensing of Rogue Waves

    NASA Astrophysics Data System (ADS)

    Parsons, Wade; Kadri, Usama

    2016-04-01

    We propose an early warning system for approaching rogue waves using the remote sensing of acoustic-gravity waves (AGWs) - progressive sound waves that propagate at the speed of sound in the ocean. It is believed that AGWs are generated during the formation of rogue waves, carrying information on the rogue waves at near the speed of sound, i.e. much faster than the rogue wave. The capability of identifying those special sound waves would enable detecting rogue waves most efficiently. A lot of promising work has been reported on AGWs in the last few years, part of which in the context of remote sensing as an early detection of tsunami. However, to our knowledge none of the work addresses the problem of rogue waves directly. Although there remains some uncertainty as to the proper definition of a rogue wave, there is little doubt that they exist and no one can dispute the potential destructive power of rogue waves. An early warning system for such extreme waves would become a demanding safety technology. A closed form expression was developed for the pressure induced by an impulsive source at the free surface (the Green's function) from which the solution for more general sources can be developed. In particular, we used the model of the Draupner Wave of January 1st, 1995 as a source and calculated the induced AGW signature. In particular we studied the AGW signature associated with a special feature of this wave, and characteristic of rogue waves, of the absence of any local set-down beneath the main crest and the presence of a large local set-up.

  13. Improved Multiple-DOF SAW Piezoelectric Motors

    NASA Technical Reports Server (NTRS)

    Bar-Cohen, Yoseph; Bao, Xiaoqi; Hull, Anthony; Wright, John

    2003-01-01

    Surface-acoustic-wave (SAW) piezoelectric motors of a proposed type would be capable of operating in multiple degrees of freedom (DOFs) simultaneously and would be amenable to integration into diverse structures and mechanisms. These motors would be compact and structurally simple and would not contain bearings or lead screws. One example of a particularly useful motor of this type would be a two-dimensional- translation stage. Another such example would be a self-actuated spherical joint that could be made to undergo controlled, simultaneous rotations about two orthogonal axes: Such a motor could serve as a mechanism for aiming an "eyeball" camera or as a compact transducer in, and an integral part of, a joint in a robot arm. The multiple-DOF SAW piezoelectric motors as now proposed would be successors to the ones reported in "Multiple-DOF Surface-Acoustic-Wave Piezoelectric Motors" (NPO-20735), NASA Tech Briefs, Vol. 24, No. 12 (December 2000), page 5b. The basic principle of operation of a multiple-DOF SAW piezoelectric motor is a straightforward extension of that of single-DOF SAW piezoelectric motors, which have been reported in several previous NASA Tech Briefs articles: For example, in the case of a linear SAW piezoelectric motor, piezoelectric transducers at opposite ends of a stator excite surface acoustic waves that travel along the surface of the stator. An object (denoted the slider) is pressed against the stator with sufficient pressure (in practice .300 MPa) that it remains in frictional contact with the stator at all times. The slider rides the crests of the waves and is thereby made to move along the surface of the stator. The direction of motion (forward or backward) is controlled by selecting the relative phase of waves generated by the two piezoelectric transducers. The speed increases with the amplitude of the waves and thus with the magnitude of the voltage applied to the transducers.

  14. Modulation of a quantum positron acoustic wave

    NASA Astrophysics Data System (ADS)

    Amin, M. R.

    2015-09-01

    Amplitude modulation of a positron acoustic wave is considered in a four-component electron-positron plasma in the quantum magnetohydrodynamic regime. The important ingredients of this study are the inclusion of the particle exchange-correlation potential, quantum diffraction effects via the Bohm potential, and dissipative effect due to viscosity in the momentum balance equation of the charged carriers. A modified nonlinear Schrödinger equation is derived for the evolution of the slowly varying amplitude of the quantum positron acoustic wave by employing the standard reductive perturbation technique. Detailed analysis of the linear and nonlinear dispersions of the quantum positron acoustic wave is presented. For a typical parameter range, relevant to some dense astrophysical objects, it is found that the quantum positron acoustic wave is modulationally unstable above a certain critical wavenumber. Effects of the exchange-correlation potential and the Bohm potential in the wave dynamics are also studied. It is found that the quantum effect due to the particle exchange-correlation potential is significant in comparison to the effect due to the Bohm potential for smaller values of the carrier wavenumber. However, for comparatively larger values of the carrier wavenumber, the Bohm potential effect overtakes the effect of the exchange-correlation potential. It is found that the critical wavenumber for the modulation instability depends on the ratio of the equilibrium hot electron number density and the cold positron number density and on the ratio of the equilibrium hot positron number density and the cold positron number density. A numerical result on the growth rate of the modulation instability is also presented.

  15. New Application of Shear Horizontal Surface Acoustic Wave Sensors to Identifying Fruit Juices

    NASA Astrophysics Data System (ADS)

    Kondoh, Jun; Shiokawa, Showko

    1994-05-01

    The objective of this paper is to present a new application of shear horizontal surface acoustic wave (SH-SAW) devices on 36° rotated Y-cut X-propagating LiTaO3 for a sensing system that can identify liquid samples, such as fruit juices. Theoretical sensor sensitivity for acoustoelectric interaction with a liquid loaded on the SAW propagation surface was derived and confirmed with experimental results. The results strongly suggested that by employing SH-SAW devices with different center frequencies the sensor can recognize many liquid samples without a film coated on the substrate surface. In the experiment, the sensing system which identifies fruit juices was fabricated using three SH-SAW devices with center frequencies of 30, 50, and 100 MHz. Identification of samples, eleven kinds of fruit juices, was achieved by classification in principal component analysis and discriminant analysis. Since the SH-SAW sensor without a coating film has intrinsically good reproducibility and stability, it is effective for identification and quality control of liquid samples.

  16. Optical find of hypersonic surface acoustic waves in bulk transparent materials

    NASA Astrophysics Data System (ADS)

    Jiménez Riobóo, Rafael J.; Sánchez-Sánchez, Alberto; Prieto, Carlos

    2016-07-01

    It is shown that direct information from surface acoustic waves (SAWs) of bulk transparent materials can be obtained by using Brillouin light scattering (BLS). The study of surface phonons by means of an optical spectroscopy such as BLS has been historically constrained to nontransparent and highly reflecting bulk and film samples or even to very thin films deposited on reflecting substrates. Probably due to its low signal and to the narrow window in experimental conditions, it was assumed for years that bulk transparent samples were not suited for Brillouin spectroscopy in order to get information on SAWs, negating this optical technique in the search for SAW properties. The reported experiments on transparent glasses and single crystals (cubic MgO and trigonal sapphire) prove that there is no intrinsic physical reason not to collect SAW propagation velocity data from transparent bulk samples and opens a challenge to apply the Brillouin spectroscopy in a wider scenario to obtain direct information, in a nondestructive and contactless way, about SAWs in bulk materials.

  17. Low-loss unidirectional transducer for high frequency surface acoustic wave devices

    NASA Astrophysics Data System (ADS)

    Biryukov, S. V.; Martin, G.; Schmidt, H.; Wall, B.

    2011-10-01

    A multi-track unidirectional transducer for surface acoustic wave devices is presented. This transducer consists of periodic cells containing in each of the multiple tracks, only two electrodes and two gaps with quarter period width. So the structure has maximal possible dimensions of its elements for a cell period equal to one wavelength. In spite of current technological limitations this permits to implement unidirectional transducers in GHz range. In contrast to known structures with active tracks only, the structure contains alternating both active transducer tracks and passive reflector tracks with different apertures comparable to surface acoustic wave (SAW) wavelength. The tracks strongly interact due to diffraction of waves excited by such electrode structure on a piezoelectric substrate. A structure analysis by means of finite element method shows that complete unidirectionality can be reached. First experimental results are given.

  18. Surface acoustic wave technique for the characterization of porous properties of microporous silicate thin films

    NASA Astrophysics Data System (ADS)

    Hietala, Susan Leslie

    1997-12-01

    Features of gas adsorption onto sol-gel derived microporous silicate thin films, for characterization of porous properties, are detailed using a surface acoustic wave (SAW) technique. Mass uptake and film effective modulus changes calculated from the SAW data are investigated in detail. The effects of stress and surface tension on the SAW sensor are calculated and found to be negligible in these experiments. Transient behavior recorded during nitrogen adsorption at 77 K is discussed in the context of mass uptake and effective modulus contributions. The time constant associated with the effective modulus calculation is consistent with that of diffusivity of nitrogen into a 5A zeolite. Further calculations indicate that the transient behavior is not due to thermal effects. A unique dual sensor SAW experiment to decouple the mass and effective modulus contributions to the frequency response was performed in conjunction with a Silicon beam-bending experiment. The beam-bending experiment results in a calculation of stress induced during adsorption of methanol on a microporous silicate thin film. The decoupled mass and effective modulus calculated from the SAW data have similar shaped isotherms, and are quite different from that of the stress developed in the Silicon beam. The total effective modulus change calculated from the SAW data is consistent with that calculated using Gassmann's equation. The SAW system developed for this work included unique electronics and customized hardware which is suitable for work under vacuum and at temperatures from 77K to 473K. This unique setup is suitable for running thin film samples on a Micromeritics ASAP 2000 Gas Adsorption unit in automatic mode. This setup is also general enough to be compatible with a custom gas adsorption unit and the beam bending apparatus, both using standard vacuum assemblies.

  19. Vapor sensing by means of a ZnO-on-Si surface acoustic wave resonator

    NASA Astrophysics Data System (ADS)

    Martin, S. J.; Schweizer, K. S.; Schwartz, S. S.; Gunshor, R. L.

    Surface Acoustic Wave (SAW) devices can function as sensitive detectors of vapors. The high surface acoustic energy density of the device makes it extremely sensitive to the presence of molecules adsorbed from the gas phase. Mass loading by the adsorbate is the primary mechanism for the surface wave velocity perturbation. If the device is used as the frequency control element of an oscillator, perturbations in wave velocity on the order of 10 parts per billion may be resolved by means of a frequency counter. Zno-on-Si SAW resonators have been examined as vapor sensors. The piezoelectric ZnO layer permits transduction between electrical and acoustic energies, as well as endowing the surface with particular adsorptive properties. These devices exhibit C-values up to 12,000 at a resonant frequency of 109 MHZ. The resonant frequency of the device shifts upon exposure to a vapor-air mixture, with a transient response which is distinct for each of the organic vapors tested. Due to the permeability of the polycrystalline ZnO layer, the instantaneous reversibility of the resonant frequency shift is found to depend on the type of adsorbed molecule.

  20. Computation of acoustic waves in a jet

    NASA Technical Reports Server (NTRS)

    Bayliss, A.; Turkel, E.

    1978-01-01

    A numerical treatment of acoustic waves in a jet is described. The full time dependent Euler equations are used in both linear and nonlinear formulations. The computational region of integration is artificially bounded and boundary conditions are developed to simulate outgoing waves and to enable the computational domain to be substantially restricted. Higher order methods and coordinate transformations are introduced to further reduce the number of grid points as well as to increase the efficiency of the program. Numerical results are presented for time harmonic sources as well as for sources with more complicated time dependence.

  1. Mechanically robust microfluidics and bulk wave acoustics to sort microparticles

    NASA Astrophysics Data System (ADS)

    Dauson, Erin R.; Gregory, Kelvin B.; Greve, David W.; Healy, Gregory P.; Oppenheim, Irving J.

    2016-04-01

    Sorting microparticles (or cells, or bacteria) is significant for scientific, medical and industrial purposes. Research groups have used lithium niobate SAW devices to produce standing waves, and then to align microparticles at the node lines in polydimethylsiloxane (PDMS, silicone) microfluidic channels. The "tilted angle" (skewed) configuration is a recent breakthrough producing particle trajectories that cross multiple node lines, making it practical to sort particles. However, lithium niobate wafers and PDMS microfluidic channels are not mechanically robust. We demonstrate "tilted angle" microparticle sorting in novel devices that are robust, rapidly prototyped, and manufacturable. We form our microfluidic system in a rigid polymethyl methacrylate (PMMA, acrylic) prism, sandwiched by lead-zirconium-titanate (PZT) wafers, operating in through-thickness mode with inertial backing, that produce standing bulk waves. The overall configuration is compact and mechanically robust, and actuating PZT wafers in through-thickness mode is highly efficient. Moving to this novel configuration introduced new acoustics questions involving internal reflections, but we show experimental images confirming the intended nodal geometry. Microparticles in "tilted angle" devices display undulating trajectories, where deviation from the straight path increases with particle diameter and with excitation voltage to create the mechanism by which particles are sorted. We show a simplified analytical model by which a "phase space" is constructed to characterize effective particle sorting, and we compare our experimental data to the predictions from that simplified model; precise correlation is not expected and is not observed, but the important physical trends from the model are paralleled in the measured particle trajectories.

  2. Radio wave propagation and acoustic sounding

    NASA Astrophysics Data System (ADS)

    Singal, S. P.

    Radio wave propagation of the decimetric and centimetric waves depends to a large extent on the boundary layer meteorological conditions which give rise to severe fadings, very often due to multipath propagation. Sodar is one of the inexpensive remote sensing techniques which can be employed to probe the boundary layer structure. In the paper a historical perspective has been given of the simultaneously conducted studies on radio waves and sodar at various places. The radio meteorological information needed for propagation studies has been clearly spelt out and conditions of a ray path especially in the presence of a ducting layer have been defined as giving rise to fading or signal enhancement conditions. Finally the potential of the sodar studies to obtain information about the boundary layer phenomena has been stressed, clearly spelling out the use of acoustic sounding in radio wave propagation studies.

  3. Nonlinear ion acoustic waves scattered by vortexes

    NASA Astrophysics Data System (ADS)

    Ohno, Yuji; Yoshida, Zensho

    2016-09-01

    The Kadomtsev-Petviashvili (KP) hierarchy is the archetype of infinite-dimensional integrable systems, which describes nonlinear ion acoustic waves in two-dimensional space. This remarkably ordered system resides on a singular submanifold (leaf) embedded in a larger phase space of more general ion acoustic waves (low-frequency electrostatic perturbations). The KP hierarchy is characterized not only by small amplitudes but also by irrotational (zero-vorticity) velocity fields. In fact, the KP equation is derived by eliminating vorticity at every order of the reductive perturbation. Here, we modify the scaling of the velocity field so as to introduce a vortex term. The newly derived system of equations consists of a generalized three-dimensional KP equation and a two-dimensional vortex equation. The former describes 'scattering' of vortex-free waves by ambient vortexes that are determined by the latter. We say that the vortexes are 'ambient' because they do not receive reciprocal reactions from the waves (i.e., the vortex equation is independent of the wave fields). This model describes a minimal departure from the integrable KP system. By the Painlevé test, we delineate how the vorticity term violates integrability, bringing about an essential three-dimensionality to the solutions. By numerical simulation, we show how the solitons are scattered by vortexes and become chaotic.

  4. Full skin quantitative optical coherence elastography achieved by combining vibration and surface acoustic wave methods

    NASA Astrophysics Data System (ADS)

    Li, Chunhui; Guan, Guangying; Huang, Zhihong; Wang, Ruikang K.; Nabi, Ghulam

    2015-03-01

    By combining with the phase sensitive optical coherence tomography (PhS-OCT), vibration and surface acoustic wave (SAW) methods have been reported to provide elastography of skin tissue respectively. However, neither of these two methods can provide the elastography in full skin depth in current systems. This paper presents a feasibility study on an optical coherence elastography method which combines both vibration and SAW in order to give the quantitative mechanical properties of skin tissue with full depth range, including epidermis, dermis and subcutaneous fat. Experiments are carried out on layered tissue mimicking phantoms and in vivo human forearm and palm skin. A ring actuator generates vibration while a line actuator were used to excited SAWs. A PhS-OCT system is employed to provide the ultrahigh sensitive measurement of the generated waves. The experimental results demonstrate that by the combination of vibration and SAW method the full skin bulk mechanical properties can be quantitatively measured and further the elastography can be obtained with a sensing depth from ~0mm to ~4mm. This method is promising to apply in clinics where the quantitative elasticity of localized skin diseases is needed to aid the diagnosis and treatment.

  5. Effect of critical dimension variation on SAW correlator energy.

    SciTech Connect

    Skinner, Jack L.

    2005-04-01

    The effect of critical dimension (CD) variation and metallization ratio on the efficiency of energy conversion of a surface acoustic wave (SAW) correlator is examined. We find that a 10% variation in the width of finger electrodes predicts only a 1% decrease in the efficiency of energy conversion. Furthermore, our model predicts that a metallization ratio of 0.74 represents an optimum value for energy extraction from the SAW by the interdigitated transducer (IDT).

  6. Numerical simulation on development of a SAW based biosensor

    NASA Astrophysics Data System (ADS)

    Ten, S. T.; Hashim, U.; Sudin, A.; Arshad, M. K. Md.; Liu, W. W.; Foo, K. L.; Voon, C. H.; Wee, F. H.; Lee, Y. S.; Salleh, N. H. M.; Nazwa, T.

    2016-07-01

    Surface acoustic waves can be generated at the free surface of an elastic solid. For this property, surface acoustic based devices were initially developed for the telecommunication purpose such as signal filters and resonators. The acoustic energy is strongly confined on the surface of the surface acoustic waves (SAW) based devices and consequent their ultra-sensitivity to the surface perturbation. This has made SAW permits the highly sensitive detection of utterly diminutive charges on the surface. Hence, SAW based devices have been modified to be sensors for the mass loading effect on its surface and this is perfectly for biosensor development. There have been a lot of complicated theoretical models for the SAW devices development since 1960 as signal filters and resonators such as from delta function model, equivalent circuit model, to the current SAW models such as coupling-of-modes (COM) model, P-matrix model and Computer Simulation Technology Studio Suite (CST). However, these models are more tailored for the telecommunication application purposes and very complex. Thus, this paper presents the finite element analysis (FEA) modeling, COMSOL Multiphysics which is used to study the mass loading effect on SAW which will be used as biosensor. This study managed to simulate the mass loading sensitivity of 8.71×107 kHz/g mm-2.

  7. Advanced vapor recognition materials for selective and fast responsive surface acoustic wave sensors: a review.

    PubMed

    Afzal, Adeel; Iqbal, Naseer; Mujahid, Adnan; Schirhagl, Romana

    2013-07-17

    The necessity of selectively detecting various organic vapors is primitive not only with respect to regular environmental and industrial hazard monitoring, but also in detecting explosives to combat terrorism and for defense applications. Today, the huge arsenal of micro-sensors has revolutionized the traditional methods of analysis by, e.g. replacing expensive laboratory equipment, and has made the remote screening of atmospheric threats possible. Surface acoustic wave (SAW) sensors - based on piezoelectric crystal resonators - are extremely sensitive to even very small perturbations in the external atmosphere, because the energy associated with the acoustic waves is confined to the crystal surface. Combined with suitably designed molecular recognition materials SAW devices could develop into highly selective and fast responsive miniaturized sensors, which are capable of continuously monitoring a specific organic gas, preferably in the sub-ppm regime. For this purpose, different types of recognition layers ranging from nanostructured metal oxides and carbons to pristine or molecularly imprinted polymers and self-assembled monolayers have been applied in the past decade. We present a critical review of the recent developments in nano- and micro-engineered synthetic recognition materials predominantly used for SAW-based organic vapor sensors. Besides highlighting their potential to realize real-time vapor sensing, their limitations and future perspectives are also discussed.

  8. Multilayer graphene electrodes for one-port surface acoustic wave resonator mass sensor

    NASA Astrophysics Data System (ADS)

    Leong, Ainan; Swamy, Varghese; Ramakrishnan, N.

    2017-02-01

    A one-port surface acoustic wave (SAW) resonator mass sensor composed of multilayer graphene (MLG) electrodes was investigated by the finite element method (FEM) and analyses were carried out to study the enhancement of sensitivity and the secondary effects caused by MLG electrodes on the performance of the resonator. Unlike metal electrodes, MLG electrode offers elastic loading to the contact surface, as evidenced by the increase in the surface velocity of the SAW device. In terms of the sensitivity of the mass sensor, MLG electrode showed the largest center frequency shift in response to a change in mass loading, as well as when used as a gas sensor to detect volatile organic compounds (VOCs). Also, MLG electrodes offered the least triple transit signal (TTS) and bulk acoustic wave (BAW) generations compared with Al and Au–Cr electrodes. Thus, the one-port SAW resonator with graphene electrodes not only possesses excellent performance characteristics but also gives rise to new opportunities in the development of highly sensitive mass sensors.

  9. Effective Use of Molecular Recognition in Gas Sensing: Results from Acoustic Wave and In-Situ FTIR Measurements

    SciTech Connect

    Bodenhofer, K,; Gopel, W.; Hierlemann, A.; Ricco, A.J.

    1998-12-09

    To probe directly the analyte/film interactions that characterize molecular recognition in gas sensors, we recorded changes to the in-situ surface vibrational spectra of specifically fictionalized surface acoustic wave (SAW) devices concurrently with analyte exposure and SAW measurement of the extent of sorption. Fourier-lmnsform infrared external- reflectance spectra (FTIR-ERS) were collected from operating 97-MH2 SAW delay lines during exposure to a range of analytes as they interacted with thin-film coatings previously shown to be selective: cyclodextrins for chiral recognition, Ni-camphorates for Lewis bases such as pyridine and organophosphonates, and phthalocyanines for aromatic compounds. In most cases where specific chemical interactions-metal coordination, "cage" compound inclusion, or z stacking-were expected, analyte dosing caused distinctive changes in the IR spectr~ together with anomalously large SAW sensor responses. In contrast, control experiments involving the physisorption of the same analytes by conventional organic polymers did not cause similar changes in the IR spectra, and the SAW responses were smaller. For a given conventional polymer, the partition coefficients (or SAW sensor signals) roughly followed the analyte fraction of saturation vapor pressure. These SAW/FTIR results support earlier conclusions derived from thickness-shear mode resonator data.

  10. A process to control light in a micro resonator through a coupling modulation by surface acoustic waves

    PubMed Central

    Fan, Guofang; Li, Yuan; Hu, Chunguang; Lei, Lihua; Guo, Yanchuan

    2016-01-01

    A novel process to control light through the coupling modulation by surface acoustic wave (SAW) is presented in an optical micro resonator. An optical waveguide modulator of a racetrack resonator on silicon-on-insulator (SOI) technology is took as an example to explore the mechanism. A finite-difference time-domain (FDTD) is developed to simulate the acousto-optical (AO) modulator using the mechanism. An analytical method is presented to verify our proposal. The results show that the process can work well as an optical modulator by SAW. PMID:27485470

  11. A process to control light in a micro resonator through a coupling modulation by surface acoustic waves

    NASA Astrophysics Data System (ADS)

    Fan, Guofang; Li, Yuan; Hu, Chunguang; Lei, Lihua; Guo, Yanchuan

    2016-08-01

    A novel process to control light through the coupling modulation by surface acoustic wave (SAW) is presented in an optical micro resonator. An optical waveguide modulator of a racetrack resonator on silicon-on-insulator (SOI) technology is took as an example to explore the mechanism. A finite-difference time-domain (FDTD) is developed to simulate the acousto-optical (AO) modulator using the mechanism. An analytical method is presented to verify our proposal. The results show that the process can work well as an optical modulator by SAW.

  12. Theoretical Study of the Effect of Enamel Parameters on Laser-Induced Surface Acoustic Waves in Human Incisor

    NASA Astrophysics Data System (ADS)

    Yuan, Ling; Sun, Kaihua; Shen, Zhonghua; Ni, Xiaowu; Lu, Jian

    2015-06-01

    The laser ultrasound technique has great potential for clinical diagnosis of teeth because of its many advantages. To study laser surface acoustic wave (LSAW) propagation in human teeth, two theoretical methods, the finite element method (FEM) and Laguerre polynomial extension method (LPEM), are presented. The full field temperature values and SAW displacements in an incisor can be obtained by the FEM. The SAW phase velocity in a healthy incisor and dental caries is obtained by the LPEM. The methods and results of this work can provide a theoretical basis for nondestructive evaluation of human teeth with LSAWs.

  13. Dynamic control of the optical emission from GaN/InGaN nanowire quantum dots by surface acoustic waves

    SciTech Connect

    Lazić, S. Chernysheva, E.; Meulen, H. P. van der; Calleja Pardo, J. M.; Gačević, Ž.; Calleja, E.

    2015-09-15

    The optical emission of InGaN quantum dots embedded in GaN nanowires is dynamically controlled by a surface acoustic wave (SAW). The emission energy of both the exciton and biexciton lines is modulated over a 1.5 meV range at ∼330 MHz. A small but systematic difference in the exciton and biexciton spectral modulation reveals a linear change of the biexciton binding energy with the SAW amplitude. The present results are relevant for the dynamic control of individual single photon emitters based on nitride semiconductors.

  14. Passive Wireless SAW Sensors for IVHM

    NASA Technical Reports Server (NTRS)

    Wilson, William C.; Perey, Daniel F.; Atkinson, Gary M.; Barclay, Rebecca O.

    2008-01-01

    NASA aeronautical programs require integrated vehicle health monitoring (IVHM) to ensure the safety of the crew and the vehicles. Future IVHM sensors need to be small, light weight, inexpensive, and wireless. Surface acoustic wave (SAW) technology meets all of these constraints. In addition it operates in harsh environments and over wide temperature ranges, and it is inherently radiation hardened. This paper presents a survey of research opportunities for universities and industry to develop new sensors that address anticipated IVHM needs for aerospace vehicles. Potential applications of passive wireless SAW sensors from ground testing to high altitude aircraft operations are presented, along with some of the challenges and issues of the technology.

  15. L-Band Front End SAW Filters.

    DTIC Science & Technology

    1981-04-01

    design of L-band SAW Filters for the Global - Positioning System ( GPS ) RF front end is described. Filters on lithium niobate with loss as low as 4.5 dB at...INTRODUCTION The performance of the Global Positioning System ( GPS ) receiver may be greatly improved by incorporation of L-Band Surface Acoustic Wave...SAW) filters. The RF front end of the GPS system is shown in Figure 1. Microwave power incident on the GPS antenna is amplified and diplexed. Signals

  16. Novel Acoustic Wave Microsystems for Biophysical Studies of Cells

    NASA Astrophysics Data System (ADS)

    Senveli, Sukru Ufuk

    Single cell analysis is an important topic for understanding of diseases. In this understanding, biomechanics approach serves as an important tool as it relates and connects the mechanical properties of biological cells with diseases such as cancer. In this context, analysis methods based on ultrasonics are promising owing to their non-invasive nature and ease of use. However, there is a lack of miniature systems that provide accurate ultrasonic measurements on single cancer cells for diagnostic purposes. The platform presented in this study exploits high frequency acoustic interaction and uses direct coupling of Rayleigh type SAWs with various samples placed inside microcavities to analyze their structural properties. The samples used are aqueous glycerin solutions and polystyrene microbeads for demonstrating proper system operation, and lead up to biological cells. The microcavity is instrumental in trapping a predetermined volume of sample inside and facilitating the interaction of the surface waves with the sample in question via a resonance condition. Ultimately, the resultant SAW reaching the output transducer incurs a phase delay due to its interaction with the sample in the microcavity. The system operates in a different manner compared to similar systems as a result of multiple wave reflections in the small volume and coupling back to the piezoelectric substrate. The proposed microsystem was first analyzed using finite element methods. Liquid and solid media were modeled by considering frequency dependent characteristics. Similarly, mechanical behavior of cells with respect to different conditions is considered, and biological cells are modeled accordingly. Prototype devices were fabricated on quartz and lithium niobate in a cleanroom environment. Process steps were optimized separately for devices with microcavities. Precise fabrication, alignment, and bonding of PDMS microchannels were carried out. Soft microprobes were fabricated out of SU-8, a

  17. Surface acoustic wave devices as passive buried sensors

    NASA Astrophysics Data System (ADS)

    Friedt, J.-M.; Rétornaz, T.; Alzuaga, S.; Baron, T.; Martin, G.; Laroche, T.; Ballandras, S.; Griselin, M.; Simonnet, J.-P.

    2011-02-01

    Surface acoustic wave (SAW) devices are currently used as passive remote-controlled sensors for measuring various physical quantities through a wireless link. Among the two main classes of designs—resonator and delay line—the former has the advantage of providing narrow-band spectrum informations and hence appears compatible with an interrogation strategy complying with Industry-Scientific-Medical regulations in radio-frequency (rf) bands centered around 434, 866, or 915 MHz. Delay-line based sensors require larger bandwidths as they consists of a few interdigitated electrodes excited by short rf pulses with large instantaneous energy and short response delays but is compatible with existing equipment such as ground penetrating radar (GPR). We here demonstrate the measurement of temperature using the two configurations, particularly for long term monitoring using sensors buried in soil. Although we have demonstrated long term stability and robustness of packaged resonators and signal to noise ratio compatible with the expected application, the interrogation range (maximum 80 cm) is insufficient for most geology or geophysical purposes. We then focus on the use of delay lines, as the corresponding interrogation method is similar to the one used by GPR which allows for rf penetration distances ranging from a few meters to tens of meters and which operates in the lower rf range, depending on soil water content, permittivity, and conductivity. Assuming propagation losses in a pure dielectric medium with negligible conductivity (snow or ice), an interrogation distance of about 40 m is predicted, which overcomes the observed limits met when using interrogation methods specifically developed for wireless SAW sensors, and could partly comply with the above-mentioned applications. Although quite optimistic, this estimate is consistent with the signal to noise ratio observed during an experimental demonstration of the interrogation of a delay line buried at a depth of 5

  18. Evaluation on Micro Cracks in Ceramic Bearing Balls by Using the Floating Resonance of Surface Acoustic Waves

    NASA Astrophysics Data System (ADS)

    Cho, Hideo; Komatsu, Kouichi; Ishikawa, Satoru; Tanimoto, Kiyoshi; Takii, Hirokazu; Yamanaka, Kazushi

    2003-05-01

    Although resonant ultrasound spectroscopy is useful for testing the surface and the inside of objects, the acoustic properties (resonance frequency, mode amplitude ratio, attenuation, etc.) are disturbed by the contact made with supports and transducers. To eliminate this disturbance, we developed the floating resonance (FR) method in which the acoustic properties of bulk and surface acoustic waves (SAWs) are evaluated using laser ultrasound after floating the objects, thus avoiding the contact with the supports and transducers. In this work we applied the FR method to detect artificial flaws on the surface of ceramic bearing balls and a slit as shallow as 50 μm was successfully detected from the attenuation of SAWs after multiple round trips with as many as 20 turns.

  19. Twisted electron-acoustic waves in plasmas

    NASA Astrophysics Data System (ADS)

    Aman-ur-Rehman, Ali, S.; Khan, S. A.; Shahzad, K.

    2016-08-01

    In the paraxial limit, a twisted electron-acoustic (EA) wave is studied in a collisionless unmagnetized plasma, whose constituents are the dynamical cold electrons and Boltzmannian hot electrons in the background of static positive ions. The analytical and numerical solutions of the plasma kinetic equation suggest that EA waves with finite amount of orbital angular momentum exhibit a twist in its behavior. The twisted wave particle resonance is also taken into consideration that has been appeared through the effective wave number qeff accounting for Laguerre-Gaussian mode profiles attributed to helical phase structures. Consequently, the dispersion relation and the damping rate of the EA waves are significantly modified with the twisted parameter η, and for η → ∞, the results coincide with the straight propagating plane EA waves. Numerically, new features of twisted EA waves are identified by considering various regimes of wavelength and the results might be useful for transport and trapping of plasma particles in a two-electron component plasma.

  20. Acceleration of solitary ion-acoustic surface waves

    NASA Astrophysics Data System (ADS)

    Stenflo, L.; Gradov, O. M.

    1991-10-01

    We consider the interaction between long-wavelength ion-acoustic and electron-plasma surface waves on a semi-infinite plasma. It then turns out that an ion-acoustic solitary wave can be accelerated when the amplitude of the electron-plasma surface wave varies in time.

  1. Identification of rocket-induced acoustic waves in the ionosphere

    NASA Astrophysics Data System (ADS)

    Mabie, Justin; Bullett, Terence; Moore, Prentiss; Vieira, Gerald

    2016-10-01

    Acoustic waves can create plasma disturbances in the ionosphere, but the number of observations is limited. Large-amplitude acoustic waves generated by energetic sources like large earthquakes and tsunamis are more readily observed than acoustic waves generated by weaker sources. New observations of plasma displacements caused by rocket-generated acoustic waves were made using the Vertically Incident Pulsed Ionospheric Radar (VIPIR), an advanced high-frequency radar. Rocket-induced acoustic waves which are characterized by low amplitudes relative to those induced by more energetic sources can be detected in the ionosphere using the phase data from fixed frequency radar observations of a plasma layer. This work is important for increasing the number and quality of observations of acoustic waves in the ionosphere and could help improve the understanding of energy transport from the lower atmosphere to the thermosphere.

  2. Ultrasound acoustic wave energy transfer and harvesting

    NASA Astrophysics Data System (ADS)

    Shahab, Shima; Leadenham, Stephen; Guillot, François; Sabra, Karim; Erturk, Alper

    2014-04-01

    This paper investigates low-power electricity generation from ultrasound acoustic wave energy transfer combined with piezoelectric energy harvesting for wireless applications ranging from medical implants to naval sensor systems. The focus is placed on an underwater system that consists of a pulsating source for spherical wave generation and a harvester connected to an external resistive load for quantifying the electrical power output. An analytical electro-acoustic model is developed to relate the source strength to the electrical power output of the harvester located at a specific distance from the source. The model couples the energy harvester dynamics (piezoelectric device and electrical load) with the source strength through the acoustic-structure interaction at the harvester-fluid interface. Case studies are given for a detailed understanding of the coupled system dynamics under various conditions. Specifically the relationship between the electrical power output and system parameters, such as the distance of the harvester from the source, dimensions of the harvester, level of source strength, and electrical load resistance are explored. Sensitivity of the electrical power output to the excitation frequency in the neighborhood of the harvester's underwater resonance frequency is also reported.

  3. Acoustic field distribution of sawtooth wave with nonlinear SBE model

    SciTech Connect

    Liu, Xiaozhou Zhang, Lue; Wang, Xiangda; Gong, Xiufen

    2015-10-28

    For precise prediction of the acoustic field distribution of extracorporeal shock wave lithotripsy with an ellipsoid transducer, the nonlinear spheroidal beam equations (SBE) are employed to model acoustic wave propagation in medium. To solve the SBE model with frequency domain algorithm, boundary conditions are obtained for monochromatic and sawtooth waves based on the phase compensation. In numerical analysis, the influence of sinusoidal wave and sawtooth wave on axial pressure distributions are investigated.

  4. An emerging reactor technology for chemical synthesis: surface acoustic wave-assisted closed-vessel Suzuki coupling reactions.

    PubMed

    Kulkarni, Ketav; Friend, James; Yeo, Leslie; Perlmutter, Patrick

    2014-07-01

    In this paper we demonstrate the use of an energy-efficient surface acoustic wave (SAW) device for driving closed-vessel SAW-assisted (CVSAW), ligand-free Suzuki couplings in aqueous media. The reactions were carried out on a mmolar scale with low to ultra-low catalyst loadings. The reactions were driven by heating resulting from the penetration of acoustic energy derived from RF Raleigh waves generated by a piezoelectric chip via a renewable fluid coupling layer. The yields were uniformly high and the reactions could be executed without added ligand and in water. In terms of energy density this new technology was determined to be roughly as efficient as microwaves and superior to ultrasound.

  5. Imaging of transient surface acoustic waves by full-field photorefractive interferometry

    SciTech Connect

    Xiong, Jichuan; Xu, Xiaodong E-mail: christ.glorieux@fys.kuleuven.be; Glorieux, Christ E-mail: christ.glorieux@fys.kuleuven.be; Matsuda, Osamu; Cheng, Liping

    2015-05-15

    A stroboscopic full-field imaging technique based on photorefractive interferometry for the visualization of rapidly changing surface displacement fields by using of a standard charge-coupled device (CCD) camera is presented. The photorefractive buildup of the space charge field during and after probe laser pulses is simulated numerically. The resulting anisotropic diffraction upon the refractive index grating and the interference between the polarization-rotated diffracted reference beam and the transmitted signal beam are modeled theoretically. The method is experimentally demonstrated by full-field imaging of the propagation of photoacoustically generated surface acoustic waves with a temporal resolution of nanoseconds. The surface acoustic wave propagation in a 23 mm × 17 mm area on an aluminum plate was visualized with 520 × 696 pixels of the CCD sensor, yielding a spatial resolution of 33 μm. The short pulse duration (8 ns) of the probe laser yields the capability of imaging SAWs with frequencies up to 60 MHz.

  6. Detection of cells captured with antigens on shear horizontal surface-acoustic-wave sensors.

    PubMed

    Hao, Hsu-Chao; Chang, Hwan-You; Wang, Tsung-Pao; Yao, Da-Jeng

    2013-02-01

    Techniques to separate cells are widely applied in immunology. The technique to separate a specific antigen on a microfluidic platform involves the use of a shear horizontal surface-acoustic-wave (SH-SAW) sensor. With specific antibodies conjugated onto the surface of the SH-SAW sensors, this technique can serve to identify specific cells in bodily fluids. Jurkat cells, used as a target in this work, provide a model of cells in small abundance (1:1000) for isolation and purification with the ultimate goal of targeting even more dilute cells. T cells were separated from a mixed-cell medium on a chip (Jurkat cells/K562 cells, 1/1000). A novel microchamber was developed to capture cells during the purification, which required a large biosample. Cell detection was demonstrated through the performance of genetic identification on the chip.

  7. Detection of bioagents using a shear horizontal surface acoustic wave biosensor

    DOEpatents

    Larson, Richard S; Hjelle, Brian; Hall, Pam R; Brown, David C; Bisoffi, Marco; Brozik, Susan M; Branch, Darren W; Edwards, Thayne L; Wheeler, David

    2014-04-29

    A biosensor combining the sensitivity of surface acoustic waves (SAW) generated at a frequency of 325 MHz with the specificity provided by antibodies and other ligands for the detection of viral agents. In a preferred embodiment, a lithium tantalate based SAW transducer with silicon dioxide waveguide sensor platform featuring three test and one reference delay lines was used to adsorb antibodies directed against Coxsackie virus B4 or the negative-stranded category A bioagent Sin Nombre virus (SNV). Rapid detection of increasing concentrations of viral particles was linear over a range of order of magnitude for both viruses, and the sensor's selectivity for its target was not compromised by the presence of confounding Herpes Simplex virus type 1 The biosensor was able to delect SNV at doses lower than the load of virus typically found in a human patient suffering from hantavirus cardiopulmonary syndrome (HCPS).

  8. Graphene-like nano-sheets for surface acoustic wave gas sensor applications

    NASA Astrophysics Data System (ADS)

    Arsat, R.; Breedon, M.; Shafiei, M.; Spizziri, P. G.; Gilje, S.; Kaner, R. B.; Kalantar-zadeh, K.; Wlodarski, W.

    2009-01-01

    The gas sensing properties of graphene-like nano-sheets deposited on 36° YX lithium tantalate (LiTaO 3) surface acoustic wave (SAW) transducers are reported. The thin graphene-like nano-sheets were produced via the reduction of graphite oxide which was deposited on SAW interdigitated transducers (IDTs). Their sensing performance was assessed towards hydrogen (H 2) and carbon monoxide (CO) in a synthetic air carrier gas at room temperature (25 °C) and 40 °C. Raman and X-ray photoelectron spectroscopy (XPS) revealed that the deposited graphite oxide (GO) was not completely reduced creating small, graphitic nanocrystals ˜2.7 nm in size.

  9. Multiplex transmission system for gate drive signals of inverter circuit using surface acoustic wave filters

    NASA Astrophysics Data System (ADS)

    Suzuki, Akifumi; Ueda, Kensuke; Goka, Shigeyoshi; Wada, Keiji; Kakio, Shoji

    2016-07-01

    We propose and fabricate a multiplexed transmission system based on frequency-division multiple access (FDMA) with surface acoustic wave (SAW) filters. SAW filters are suitable for use in wide-gap switching devices and multilevel inverters because of their capability to operate at high temperatures, good electrical isolation, low cost, and high reliability. Our proposed system reduces the number of electrical signal wires needed to control each switching device and eliminates the need for isolation circuits, simplifying the transmission system and gate drive circuits. We successfully controlled two switching devices with a single coaxial line and confirmed the operation of a single-phase half-bridge inverter at a supply voltage of 100 V, and the total delay time to control the switching devices was less than 2.5 µs. Our experimental results validated our proposed system.

  10. Development of a novel odor measurement system using gas chromatography with surface acoustic wave sensor.

    PubMed

    Staples, Edward J; Viswanathan, Shekar

    2008-12-01

    This paper describes a novel odor measurement system for creating arrays of virtual chemical sensors with nonoverlapping responses using ultrahigh-speed gas chromatography with a surface acoustic wave sensor (GC/SAW). This GC/SAW system provides high-resolution two-dimensional olfactory images for easy recognition of many complex odors. Separation and quantification of the individual chemicals within an odor is performed in seconds. Using a solid-state mass-sensitive detector, picogram sensitivity, universal nonpolar selectivity, and electronically variable sensitivity are achieved. An integrated vapor preconcentrator coupled with the electronically variable detector allows the system to measure vapor concentrations spanning 6 or more orders of magnitude. The system attributes of high speed, accuracy, and precision provide a cost-effective and complimentary tool for traditional sensory evaluations.

  11. A high sensitivity wireless mass-loading surface acoustic wave DNA biosensor

    NASA Astrophysics Data System (ADS)

    Cai, Hua-Lin; Yang, Yi; Zhang, Yi-Han; Zhou, Chang-Jian; Guo, Cang-Ran; Liu, Jing; Ren, Tian-Ling

    2014-03-01

    In this paper, a surface acoustic wave (SAW) biosensor with gold delay area on LiNbO3 substrate detecting DNA sequences is proposed. By well-designed device parameters of the SAW sensor, it achieves a high performance for highly sensitive detection of target DNA. In addition, an effective biological treatment method for DNA immobilization and abundant experimental verification of the sensing effect have made it a reliable device in DNA detection. The loading mass of the probe and target DNA sequences is obtained from the frequency shifts, which are big enough in this work due to an effective biological treatment. The experimental results show that the biosensor has a high sensitivity of 1.2 pg/ml/Hz and high selectivity characteristic is also verified by the few responses of other substances. In combination with wireless transceiver, we develop a wireless receiving and processing system that can directly display the detection results.

  12. Influence of intermediate aminodextran layers on the signal response of surface acoustic wave biosensors.

    PubMed

    Länge, Kerstin; Rapp, Michael

    2008-06-15

    Surface acoustic wave (SAW) devices based on horizontally polarized surface shear waves enable direct and label-free detection of proteins in real time. Binding reactions on the sensor surface are detected by determining changes in surface wave velocity caused mainly by mass adsorption or change of viscoelasticity in the sensing layer. Intermediate hydrogel layers have been proven to be useful to immobilize capture molecules or ligands corresponding to the analyte. However, the SAW signal response strongly depends on the morphology of the hydrogel due to different relative changes of its acoustomechanical parameters such as viscoelasticity and density. In this work five aminodextrans (AMD) and one diamino polyethylene glycol (DA-PEG) were used as intermediate hydrogel layers. Sensors with immobilized streptavidin and samples containing biotinylated bovine serum albumin were used to exemplify affinity assays based on immobilized capture molecules for protein detection. The effects of the three-dimensional AMDs and the two-dimensional (2D) DA-PEG on the SAW signal response were investigated. The signal height decreased with increasing molar mass and increasing amount of immobilized AMD. Consequently, thin hydrogel layers are ideal to obtain optimum signal responses in this type of assay, whereas it is not necessarily a 2D hydrogel that gives the best results.

  13. Rapid microscale in-gel processing and digestion of proteins using surface acoustic waves.

    PubMed

    Kulkarni, Ketav P; Ramarathinam, Sri H; Friend, James; Yeo, Leslie; Purcell, Anthony W; Perlmutter, Patrick

    2010-06-21

    A new method for in-gel sample processing and tryptic digestion of proteins is described. Sample preparation, rehydration, in situ digestion and peptide extraction from gel slices are dramatically accelerated by treating the gel slice with surface acoustic waves (SAWs). Only 30 minutes total workflow time is required for this new method to produce base peak chromatograms (BPCs) of similar coverage and intensity to those observed for traditional processing and overnight digestion. Simple set up, good reproducibility, excellent peptide recoveries, rapid turnover of samples and high confidence protein identifications put this technology at the fore-front of the next generation of proteomics sample processing tools.

  14. Dual-mode acoustic wave biosensors microarrays

    NASA Astrophysics Data System (ADS)

    Auner, Gregory W.; Shreve, Gina; Ying, Hao; Newaz, Golam; Hughes, Chantelle; Xu, Jianzeng

    2003-04-01

    We have develop highly sensitive and selective acoustic wave biosensor arrays with signal analysis systems to provide a fingerprint for the real-time identification and quantification of a wide array of bacterial pathogens and environmental health hazards. We have developed an unique highly sensitive dual mode acoustic wave platform prototype that, when combined with phage based selective detection elements, form a durable bacteria sensor. Arrays of these new real-time biosensors are integrated to form a biosensor array on a chip. This research and development program optimizes advanced piezoelectric aluminum nitride wide bandgap semiconductors, novel micromachining processes, advanced device structures, selective phage displays development and immobilization techniques, and system integration and signal analysis technology to develop the biosensor arrays. The dual sensor platform can be programmed to sense in a gas, vapor or liquid environment by switching between acoustic wave resonate modes. Such a dual mode sensor has tremendous implications for applications involving monitoring of pathogenic microorganisms in the clinical setting due to their ability to detect airborne pathogens. This provides a number of applications including hospital settings such as intensive care or other in-patient wards for the reduction of nosocomial infections and maintenance of sterile environments in surgical suites. Monitoring for airborn pathogen transmission in public transportation areas such as airplanes may be useful for implementation of strategies for redution of airborn transmission routes. The ability to use the same sensor in the liquid sensing mode is important for tracing the source of airborn pathogens to local liquid sources. Sensing of pathogens in saliva will be useful for sensing oral pathogens and support of decision-making strategies regarding prevention of transmission and support of treatment strategies.

  15. Surface-Acoustic-Wave Piezoelectric Microbalance

    NASA Technical Reports Server (NTRS)

    Chuan, Raymond L.; Bowers, William D.

    1992-01-01

    Improved piezoelectric microbalances developed for use in measuring masses of volcanic, aerosol, and other small particles suspended in air. Sensitive microbalance used to analyze airborne particles in real time in environments as diverse as clean rooms or upper atmosphere. Surface-acoustic-wave resonator includes input and output sets of interdigitated electrodes and two passive conductive patterns acting as reflectors. Mechanical energy travels both ways out from middle and reflected back toward middle. Microbalance and associated circuitry fit in small package. Circuit draws only 80 mA at 5 V. Sensitivity more than 400 times that of bulk piezoelectric microbalance.

  16. Surface acoustic wave enabled pipette on a chip.

    PubMed

    Sesen, Muhsincan; Devendran, Citsabehsan; Malikides, Sean; Alan, Tuncay; Neild, Adrian

    2017-01-31

    Mono-disperse droplet formation in microfluidic devices allows the rapid production of thousands of identical droplets and has enabled a wide range of chemical and biological studies through repeat tests performed at pico-to-nanoliter volume samples. However, it is exactly this efficiency of production which has hindered the ability to carefully control the location and quantity of the distribution of various samples on a chip - the key requirement for replicating micro well plate based high throughput screening in vastly reduced volumetric scales. To address this need, here, we present a programmable microfluidic chip capable of pipetting samples from mobile droplets with high accuracy using a non-contact approach. Pipette on a chip (PoaCH) system selectively ejects (pipettes) part of a droplet into a customizable reaction chamber using surface acoustic waves (SAWs). Droplet pipetting is shown to range from as low as 150 pL up to 850 pL with precision down to tens of picoliters. PoaCH offers ease of integration with existing lab on a chip systems as well as a robust and contamination-free droplet manipulation technique in closed microchannels enabling potential implementation in screening and other studies.

  17. Finite element modelling of surface acoustic wave device based corrugated microdiaphragms

    NASA Astrophysics Data System (ADS)

    Dissanayake, Don W.; Al-Sarawi, Said; Lu, Tien-Fu; Abbott, Derek

    2009-09-01

    This paper presents modelling and analysis of microdiaphragms that are designed for implantable micropump applications. Microdiaphragms are considered to be a major component of micropumps. A securely operated, electrostatically actuated, fully passive micropump is designed using a novel method, which is based on surface acoustic wave (SAW) devices and wireless transcutaneous radio frequency (RF) communication. The device is capable of extracting the required power from the RF signal itself, like RFID (ID: identification device) tags; hence the need of a battery and active electronics is negated. Moreover, a SAW correlator is used for secure interrogation of the device. As a result, the device responds only to a unique RF signal, which has the same code as was implanted in the SAW correlator. Finite element analysis (FEA) based on code from ANSYS Inc. is carried out to model the microdiaphragm, and a Rayleigh-Ritz method based analytical model is developed to investigate the validity of the FEA results. During the FEA, a three-dimensional model of the diaphragm is developed and various kinds of corrugation profiles are considered for enhancing the device performance. A coupled-field analysis is carried out to model the electrostatics-solid interaction between the corrugated microdiaphragm and the SAW device. In modelling microdiaphragms, selection of appropriate material properties and element types, application of accurate constraints, and selection of suitable mesh parameters are carefully considered.

  18. High Efficiency Mixing Chip with Liquid Flow Actuators Operated by Surface Acoustic Waves

    NASA Astrophysics Data System (ADS)

    Saiki, Tsunemasa; Utsumi, Yuichi

    Surface acoustic wave (SAW) devices can be used as component parts for micro total analysis systems (μTASs), because the structures of these are very simple. We thus fabricated a mixing chip with liquid flow actuators operated only by the SAWs. The chip is mainly consisted of one Y-type flow channel, two pumps and one mixer. The pump is located at each upstream area of merging point of the flow channel, and the mixer is located at its downstream area. Incidentally, the flow actuators have interdigital transducers (IDTs) to generate the SAWs. The IDTs were fabricated by patterning Al/Cr on a LiNbO3 substrate, and the flow channel wall was made of epoxy-based negative resist SU-8. Using the mixing chip, we carried out a mixing experiment of two water solutions with different concentrations by using glycerin, and a chemical reaction experiment of luminol luminescence. Through the experimentations, it was found that the local and rapid mixing of continuous liquid flow was possible by using the SAW actuators, and the availability of our fabricated mixing chip as a reactor was demonstrated.

  19. On-chip temperature-compensated Love mode surface acoustic wave device for gravimetric sensing

    NASA Astrophysics Data System (ADS)

    Liu, Q.; Flewitt, A. J.

    2014-11-01

    Love mode surface acoustic wave (SAW) sensors have been recognized as one of the most sensitive devices for gravimetric sensors in liquid environments such as bio sensors. Device operation is based upon measuring changes in the transmitted (S21) frequency and phase of the first-order Love wave resonance associated with the device upon on attachment of mass. However, temperature variations also cause a change in the first order S21 parameters. In this work, shallow grooved reflectors and a "dotted" single phase unidirectional interdigitated transducer (D-SPUDT) have been added to the basic SAW structure, which promote unidirectional Love wave propagation from the device's input interdigitated transducers. Not only does this enhance the first-order S21 signal but also it allows propagation of a third-order Love wave. The attenuation coefficient of the third-order wave is sufficiently great that, whilst there is a clear reflected S11 signal, the third-order wave does not propagate into the gravimetric sensing area of the device. As a result, whilst the third-order S11 signal is affected by temperature changes, it is unaffected by mass attachment in the sensing area. It is shown that this signal can be used to remove temperature effects from the first-order S21 signal in real time. This allows gravimetric sensing to take place in an environment without the need for any other temperature measurement or temperature control; this is a particular requirement of gravimetric biosensors.

  20. The Characterization of Surface Acoustic Wave Devices Based on AlN-Metal Structures

    PubMed Central

    Shu, Lin; Peng, Bin; Li, Chuan; Gong, Dongdong; Yang, Zhengbing; Liu, Xingzhao; Zhang, Wanli

    2016-01-01

    We report in this paper on the study of surface acoustic wave (SAW) resonators based on an AlN/titanium alloy (TC4) structure. The AlN/TC4 structure with different thicknesses of AlN films was simulated, and the acoustic propagating modes were discussed. Based on the simulation results, interdigital transducers with a periodic length of 24 μm were patterned by lift-off photolithography techniques on the AlN films/TC4 structure, while the AlN film thickness was in the range 1.5–3.5 μm. The device performances in terms of quality factor (Q-factor) and electromechanical coupling coefficient (k2) were determined from the measure S11 parameters. The Q-factor and k2 were strongly dependent not only on the normalized AlN film thickness but also on the full-width at half-maximum (FWHM) of AlN (002) peak. The dispersion curve of the SAW phase velocity was analyzed, and the experimental results showed a good agreement with simulations. The temperature behaviors of the devices were also presented and discussed. The prepared SAW resonators based on AlN/TC4 structure have potential applications in integrated micromechanical sensing systems. PMID:27077864

  1. Influence of magnetic anisotropy on dynamic magnonic crystals created by surface acoustic waves in yttrium iron garnet films

    NASA Astrophysics Data System (ADS)

    Kryshtal, R. G.; Medved, A. V.

    2017-03-01

    Experimental results on the investigation of the influence of magnetic crystallographic anisotropy onto parameters of dynamic magnonic crystals arising at surface acoustic wave (SAW) propagation in yttrium iron garnet (YIG) films are presented. The main features of such an influence, as we have shown, are: 1) appearance of extra magnonic band gaps together with the normal magnonic band gap existing without anisotropy, 2) the absence of reflections of the incident surface magnetostatic wave at the frequency of these extra gaps, 3) the same depth for the extra gaps was achieved with a relatively small SAW power, almost by the order of magnitude less than in the case of normal magnonic gaps caused by SAW. A possible explanation of the features is given on the base of inelastic scattering of surface magnetostatic waves by SAW with the transformation of the reflected surface wave to the anisotropic direct volume magnetostatic wave existence of which is due to cubic crystallographic anisotropy in YIG. These results may be useful in designing new devices of information processing.

  2. Porous silicon bulk acoustic wave resonator with integrated transducer

    PubMed Central

    2012-01-01

    We report that porous silicon acoustic Bragg reflectors and AlN-based transducers can be successfully combined and processed in a commercial solidly mounted resonator production line. The resulting device takes advantage of the unique acoustic properties of porous silicon in order to form a monolithically integrated bulk acoustic wave resonator. PMID:22776697

  3. Surface Acoustic Waves to Drive Plant Transpiration

    PubMed Central

    Gomez, Eliot F.; Berggren, Magnus; Simon, Daniel T.

    2017-01-01

    Emerging fields of research in electronic plants (e-plants) and agro-nanotechnology seek to create more advanced control of plants and their products. Electronic/nanotechnology plant systems strive to seamlessly monitor, harvest, or deliver chemical signals to sense or regulate plant physiology in a controlled manner. Since the plant vascular system (xylem/phloem) is the primary pathway used to transport water, nutrients, and chemical signals—as well as the primary vehicle for current e-plant and phtyo-nanotechnology work—we seek to directly control fluid transport in plants using external energy. Surface acoustic waves generated from piezoelectric substrates were directly coupled into rose leaves, thereby causing water to rapidly evaporate in a highly localized manner only at the site in contact with the actuator. From fluorescent imaging, we find that the technique reliably delivers up to 6x more water/solute to the site actuated by acoustic energy as compared to normal plant transpiration rates and 2x more than heat-assisted evaporation. The technique of increasing natural plant transpiration through acoustic energy could be used to deliver biomolecules, agrochemicals, or future electronic materials at high spatiotemporal resolution to targeted areas in the plant; providing better interaction with plant physiology or to realize more sophisticated cyborg systems. PMID:28361922

  4. Surface Acoustic Waves to Drive Plant Transpiration.

    PubMed

    Gomez, Eliot F; Berggren, Magnus; Simon, Daniel T

    2017-03-31

    Emerging fields of research in electronic plants (e-plants) and agro-nanotechnology seek to create more advanced control of plants and their products. Electronic/nanotechnology plant systems strive to seamlessly monitor, harvest, or deliver chemical signals to sense or regulate plant physiology in a controlled manner. Since the plant vascular system (xylem/phloem) is the primary pathway used to transport water, nutrients, and chemical signals-as well as the primary vehicle for current e-plant and phtyo-nanotechnology work-we seek to directly control fluid transport in plants using external energy. Surface acoustic waves generated from piezoelectric substrates were directly coupled into rose leaves, thereby causing water to rapidly evaporate in a highly localized manner only at the site in contact with the actuator. From fluorescent imaging, we find that the technique reliably delivers up to 6x more water/solute to the site actuated by acoustic energy as compared to normal plant transpiration rates and 2x more than heat-assisted evaporation. The technique of increasing natural plant transpiration through acoustic energy could be used to deliver biomolecules, agrochemicals, or future electronic materials at high spatiotemporal resolution to targeted areas in the plant; providing better interaction with plant physiology or to realize more sophisticated cyborg systems.

  5. Random coupling of acoustic-gravity waves in the atmosphere

    NASA Astrophysics Data System (ADS)

    Millet, Christophe; Lott, Francois; Haynes, Christophe

    2016-11-01

    In numerical modeling of long-range acoustic propagation in the atmosphere, the effect of gravity waves on low-frequency acoustic waves is often ignored. As the sound speed far exceeds the gravity wave phase speed, these two types of waves present different spatial scales and their linear coupling is weak. It is possible, however, to obtain relatively strong couplings via sound speed profile changes with altitude. In the present study, this scenario is analyzed for realistic gravity wave fields and the incident acoustic wave is modeled as a narrow-banded acoustic pulse. The gravity waves are represented as a random field using a stochastic multiwave parameterization of non-orographic gravity waves. The parameterization provides independent monochromatic gravity waves, and the gravity wave field is obtained as the linear superposition of the waves produced. When the random terms are retained, a more generalized wave equation is obtained that both qualitatively and quantitatively agrees with the observations of several highly dispersed stratospheric wavetrains. Here, we show that the cumulative effect of gravity wave breakings makes the sensitivity of ground-based acoustic signals large, in that small changes in the parameterization can create or destroy an acoustic wavetrain.

  6. Development and experimental verification of a finite element method for accurate analysis of a surface acoustic wave device

    NASA Astrophysics Data System (ADS)

    Mohibul Kabir, K. M.; Matthews, Glenn I.; Sabri, Ylias M.; Russo, Salvy P.; Ippolito, Samuel J.; Bhargava, Suresh K.

    2016-03-01

    Accurate analysis of surface acoustic wave (SAW) devices is highly important due to their use in ever-growing applications in electronics, telecommunication and chemical sensing. In this study, a novel approach for analyzing the SAW devices was developed based on a series of two-dimensional finite element method (FEM) simulations, which has been experimentally verified. It was found that the frequency response of the two SAW device structures, each having slightly different bandwidth and center lobe characteristics, can be successfully obtained utilizing the current density of the electrodes via FEM simulations. The two SAW structures were based on XY Lithium Niobate (LiNbO3) substrates and had two and four electrode finger pairs in both of their interdigital transducers, respectively. Later, SAW devices were fabricated in accordance with the simulated models and their measured frequency responses were found to correlate well with the obtained simulations results. The results indicated that better match between calculated and measured frequency response can be obtained when one of the input electrode finger pairs was set at zero volts and all the current density components were taken into account when calculating the frequency response of the simulated SAW device structures.

  7. Free films of a partially wetting liquid under the influence of a propagating MHz surface acoustic wave

    NASA Astrophysics Data System (ADS)

    Altshuler, Gennady; Manor, Ofer

    2016-07-01

    We use both theory and experiment to study the response of thin and free films of a partially wetting liquid to a MHz vibration, propagating in the solid substrate in the form of a Rayleigh surface acoustic wave (SAW). We generalise the previous theory for the response of a thin fully wetting liquid film to a SAW by including the presence of a small but finite three phase contact angle between the liquid and the solid. The SAW in the solid invokes a convective drift of mass in the liquid and leaks sound waves. The dynamics of a film that is too thin to support the accumulation of the sound wave leakage is governed by a balance between the drift and capillary stress alone. We use theory to demonstrate that a partially wetting liquid film, supporting a weak capillary stress, will spread along the path of the SAW. A partially wetting film, supporting an appreciable capillary stress, will however undergo a concurrent dynamic wetting and dewetting at the front and the rear, respectively, such that the film will displace, rather than spread, along the path of the SAW. The result of the theory for a weak capillary stress is in agreement with the previous experimental and theoretical studies on the response of thin silicon oil films to a propagating SAW. No corresponding previous results exist for the case of an appreciable capillary stress. We thus complement the large capillary limit of our theory by undertaking an experimental procedure where we explore the response of films of water and a surfactant solutions to a MHz SAW, which is found to be in qualitative agreement with the theory at this limit.

  8. Parameters effects study on pulse laser for the generation of surface acoustic waves in human skin detection applications

    NASA Astrophysics Data System (ADS)

    Li, Tingting; Fu, Xing; Dorantes-Gonzalez, Dante J.; Chen, Kun; Li, Yanning; Wu, Sen

    2015-10-01

    Laser-induced Surface Acoustic Waves (LSAWs) has been promisingly and widely used in recent years due to its rapid, high accuracy and non-contact evaluation potential of layered and thin film materials. For now, researchers have applied this technology on the characterization of materials' physical parameters, like Young's Modulus, density, and Poisson's ratio; or mechanical changes such as surface cracks and skin feature like a melanoma. While so far, little research has been done on providing practical guidelines on pulse laser parameters to best generate SAWs. In this paper finite element simulations of the thermos-elastic process based on human skin model for the generation of LSAWs were conducted to give the effects of pulse laser parameters have on the generated SAWs. And recommendations on the parameters to generate strong SAWs for detection and surface characterization without cause any damage to skin are given.

  9. Acoustic microscope based on magneto-elastic wave phase conjugator

    NASA Astrophysics Data System (ADS)

    Brysev, A.; Krutyansky, L.; Pernod, P.; Preobrazhensky, V.

    2000-05-01

    Acoustic C-scan imaging (acoustic microscopy) by means of supercritical parametric wave phase conjugation (WPC) is studied experimentally. A phase conjugator based on a magneto-acoustic active material is used for compensating phase distortions introduced by solid and polymer aberration layers covering objects (electronic integrated circuits as examples). Improvement of images is demonstrated on an acoustic microscope, operating at a frequency of 10 MHz.

  10. A 300-MHz digitally compensated SAW oscillator.

    PubMed

    Cowan, W D; Slobodnik, A R; Roberts, G A; Silva, J H

    1988-01-01

    A method for compensating for the inherent temperature sensitivity of surface-acoustic-wave (SAW) oscillators is described. Results for a 300-MHz digitally compensated SAW oscillator (DCSO) show a reduction of temperature-induced frequency variation from +/-125 parts per million to +/-1.4 parts per million over the temperature range of -23 to 75 degrees C. This is accomplished using simple digital circuitry and microprocessor control. The temperature-sensing scheme, using a SAW structure with two delay paths of different temperature sensitivity on the same AT-cut quartz substrate, virtually eliminates thermal resistance and time-constant problems. Advantages over ovenized systems include fast warmup; reduced size, weight, and power dissipation; low cost potential; and the ability to compensate for other sources of frequency drift.

  11. ZnO films on /001/-cut (110)-propagating GaAs substrates for surface acoustic wave device applications

    NASA Technical Reports Server (NTRS)

    Hickernell, Frederick S.; Higgins, Robert J.; Jen, Cheng-Kuei; Kim, Yoonkee; Hunt, William D.

    1995-01-01

    A potential application for piezoelectric films substrates is the monolithic integration of surface acoustic wave (SAW) devices with GaAs electronics. Knowledge of the SAW properties of the layered structure is critical for the optimum and accurate design of such devices. The acoustic properties of ZnO films sputtered on /001/-cut group of (110) zone axes-propagating GaAs substrates are investigated in this article, including SAW velocity, effective piezoelectric coupling constant, propagation loss, diffraction, velocity surface, and reflectivity of shorted and open metallic gratings. The measurements of these essential SAW properties for the frequency range between 180 and 360 MHz have been performed using a knife-edge laser probe for film thicknesses over the range of 1.6-4 micron and with films of different grain sizes. The high quality of dc triode sputtered films was observed as evidenced by high K(sup 2) and low attenuation. The measurements of the velocity surface, which directly affects the SAW diffraction, on the bare and metalized ZnO on SiO2 or Si3N4 on /001/-cut GaAs samples are reported using two different techniques: (1) knife-edge laser probe, (2) line-focus-beam scanning acoustic microscope. It was found that near the group of (110) zone axes propagation direction, the focusing SAW property of the bare GaAs changes into a nonfocusing one for the layered structure, but a reversed phenomenon exists near the (100) direction. Furthermore, to some extent the diffraction of the substrate can be controlled with the film thickness. The reflectivity of shorted and open gratings are also analyzed and measured. Zero reflectivity is observed for a shorted grating. There is good agreement between the measured data and theoretical values.

  12. ZnO Films on {001}-Cut <110>-Propagating GaAs Substrates for Surface Acoustic Wave Device Applications

    NASA Technical Reports Server (NTRS)

    Kim, Yoonkee; Hunt, William D.; Hickernell, Frederick S.; Higgins, Robert J.; Jen, Cheng-Kuei

    1995-01-01

    A potential application for piezoelectric films on GaAs substrates is the monolithic integration of surface acoustic wave (SAW) devices with GaAs electronics. Knowledge of the SAW properties of the layered structure is critical for the optimum and accurate design of such devices. The acoustic properties of ZnO films sputtered on {001}-cut <110> -propagating GaAs substrates are investigated in this article, including SAW Velocity effective piezoelectric coupling constant, propagation loss. diffraction, velocity surface, and reflectivity of shorted and open metallic gratings. The measurements of these essential SAW properties for the frequency range between 180 and 360 MHz have been performed using a knife-edge laser probe for film thicknesses over the range of 1.6-4 micron and with films or different grain sizes. The high quality of dc triode sputtered films was observed as evidenced by high K(exp 2) and low attenuation. The measurements of the velocity surface, which directly affects the SAW diffraction, on the bare and metalized ZnO on SiO2, or Si3N4 on {001}-cut GaAs samples are reported using two different techniques: 1) knife-edge laser probe, 2) line-focus-beam scanning acoustic microscope. It was found that near the <110> propagation direction, the focusing SAW property of the bare GaAs changes into a nonfocusing one for the layered structure, but a reversed phenomenon exists near the <100> direction. Furthermore, to some extent the diffraction of the substrate can be controlled with the film thickness. The reflectivity of shorted and open gratings are also analyzed and measured. Zero reflectivity is observed for a shorted grating. There is good agreement between the measured data and theoretical values.

  13. Finite element method analysis of surface acoustic wave devices with microcavities for detection of liquids

    NASA Astrophysics Data System (ADS)

    Senveli, Sukru U.; Tigli, Onur

    2013-12-01

    This paper introduces the use of finite element method analysis tools to investigate the use of a Rayleigh type surface acoustic wave (SAW) sensor to interrogate minute amounts of liquids trapped in microcavities placed on the delay line. Launched surface waves in the ST-X quartz substrate couple to the liquid and emit compressional waves. These waves form a resonant cavity condition and interfere with the surface waves in the substrate. Simulations show that the platform operates in a different mechanism than the conventional mass loading of SAW devices. Based on the proposed detection mechanism, it is able to distinguish between variations of 40% and 90% glycerin based on phase relations while using liquid volumes smaller than 10 pl. Results from shallow microcavities show high correlation with sound velocity parameter of the liquid whereas deeper microcavities display high sensitivities with respect to glycerin concentration. Simulated devices yield a maximum sensitivity of -0.77°/(% glycerin) for 16 μm wavelength operation with 8 μm deep, 24 μm wide, and 24 μm long microcavities.

  14. Magnetic domain response to strain generated by focused surface acoustic waves

    NASA Astrophysics Data System (ADS)

    Singh, Uday; Adenwalla, Shireen

    The effects of strain on magnetostrictive ferromagnets include changes in the magnetization, anisotropy and domain wall velocities. A ferromagnet (FM) on the surface of a surface acoustic wave (SAW) is subjected to periodic compressive and tensile strain that has resulted in coherent rotation of the magnetization, as well as inducing ferromagnetic resonance in FM films. We describe the response of magnetic domains in Co/Pt multilayers when subjected to the high strains generated by a focused SAW. Annular interdigital transducers (AIDT) patterned on LiNbO3 form a SAW standing wave pattern with large strain amplitude at the focal center. Domains in [Co(3A)/Pt(8A)]x5 with perpendicular magnetic anisotropy were observed using a MOKE microscope within this focal region. Controlled magnetic pulses steered a magnetic domain boundary to the large strain region after nucleation.Excitation of the AIDT resulted in a reversible change in the domain wall boundary in the high strain region. We attribute this to magnetic anisotropy changes in the presence of RF strain, which results in changes in the domain configuration to minimize the free energy. We will present results showing both slow and fast magnetization changes in Co/Pt occurring in the presence of high frequency strain. This work is supported by NSF (DMR 1409622) and Nebraska MRSEC (DMR-1420645). This work is supported by NSF (DMR 1409622) and Nebraska MRSEC (DMR-1420645).

  15. A novel differential optical beam deflection detection system for measuring laser-generated surface acoustic waves

    NASA Astrophysics Data System (ADS)

    Shi, Yifei; Shen, Zhonghua; Ni, Xiaowu; Lu, Jian

    2008-03-01

    As the application of the laser ultrasonics developed rapidly, there is especial call for more sensitive and convenient optical installation to detect the ultrasonic waves induced by pulsed laser. The optical beam deflection (OBD) methods have abstracted the interest of people for many years for their merits over the interference method. In this paper a novel differential OBD detection system for measuring laser-generated surface acoustic waves (SAW) is presented. The detection principle of this optical system is discussed in detail according to the scheme. And we get the linear relation between the physical parameter of the SAW and the output of the detection system. For confirm the conclusion the Monte Carlo computation method is utilized to simulate the ray propagation in the system, adding the consideration of the light spot distribution of the detection laser. The numerical result agrees with the analytic method. The linear relation between the detection system output current and the deflection angle induced by SAW is validated. Furthermore, the sensitivity and the spatial resolution of the system proposed are also calculated for comparing with the other OBD methods. The results show that this differential optical beam deflection detection system is more sensitive to the small disturbance and has higher space resolution. It has considerable potential in ultrasonic measurement.

  16. Observation of self-excited acoustic vortices in defect-mediated dust acoustic wave turbulence.

    PubMed

    Tsai, Ya-Yi; I, Lin

    2014-07-01

    Using the self-excited dust acoustic wave as a platform, we demonstrate experimental observation of self-excited fluctuating acoustic vortex pairs with ± 1 topological charges through spontaneous waveform undulation in defect-mediated turbulence for three-dimensional traveling nonlinear longitudinal waves. The acoustic vortex pair has helical waveforms with opposite chirality around the low-density hole filament pair in xyt space (the xy plane is the plane normal to the wave propagation direction). It is generated through ruptures of sequential crest surfaces and reconnections with their trailing ruptured crest surfaces. The initial rupture is originated from the amplitude reduction induced by the formation of the kinked wave crest strip with strong stretching through the undulation instability. Increasing rupture causes the separation of the acoustic vortex pair after generation. A similar reverse process is followed for the acoustic vortex annihilating with the opposite-charged acoustic vortex from the same or another pair generation.

  17. Wave-wave interactions and deep ocean acoustics.

    PubMed

    Guralnik, Z; Bourdelais, J; Zabalgogeazcoa, X; Farrell, W E

    2013-10-01

    Deep ocean acoustics, in the absence of shipping and wildlife, is driven by surface processes. Best understood is the signal generated by non-linear surface wave interactions, the Longuet-Higgins mechanism, which dominates from 0.1 to 10 Hz, and may be significant for another octave. For this source, the spectral matrix of pressure and vector velocity is derived for points near the bottom of a deep ocean resting on an elastic half-space. In the absence of a bottom, the ratios of matrix elements are universal constants. Bottom effects vitiate the usual "standing wave approximation," but a weaker form of the approximation is shown to hold, and this is used for numerical calculations. In the weak standing wave approximation, the ratios of matrix elements are independent of the surface wave spectrum, but depend on frequency and the propagation environment. Data from the Hawaii-2 Observatory are in excellent accord with the theory for frequencies between 0.1 and 1 Hz, less so at higher frequencies. Insensitivity of the spectral ratios to wind, and presumably waves, is indeed observed in the data.

  18. Far-field image magnification for acoustic waves using anisotropic acoustic metamaterials.

    PubMed

    Ao, Xianyu; Chan, C T

    2008-02-01

    A kind of two-dimensional acoustic metamaterial is designed so that it exhibits strong anisotropy along two orthogonal directions. Based on the rectangular equal frequency contour of this metamaterial, magnifying lenses for acoustic waves, analogous to electromagnetic hyperlenses demonstrated recently in the optical regime, can be realized. Such metamaterial may offer applications in imaging for systems that obey scalar wave equations.

  19. X-ray diffraction and surface acoustic wave analysis of BST/Pt/TiO2/SiO2/Si thin films

    NASA Astrophysics Data System (ADS)

    Mseddi, Souhir; Njeh, Anouar; Schneider, Dieter; Fuess, Hartmut; Hédi Ben Ghozlen, Mohamed

    2011-11-01

    High dielectric constant and electrostriction property of (Ba, Sr)Ti03 (BST) thin films result in an increasing interest for dielectric devices and microwave acoustic resonator. Barium strontium titanate (Ba0.645Sr0.355TiO3) films of about 300 nm thickness are grown on Pt(111)/TiO2/SiO2/Si(001) substrates by rf magnetron sputtering deposition techniques. X-ray diffraction is applied for the microstructural characterization. The BST films exhibit a cubic perovskite structure with a dense and smooth surface. A laser acoustic waves (LA-waves) technique is used to generate surface acoustic waves (SAW) propagating in the BST films. Young's modulus E and the Poisson ratio ν of TiO2, Pt and BST films in different propagation directions are derived from the measured dispersion curves. Estimation of BST elastics constants are served in SAW studies. Impact of stratification process on SAW, propagating along [100] and [110] directions of silicon substrate, has been interpreted on the basis of ordinary differential equation (ODE) and stiffness matrix method (SMM). A good agreement is observed between experimental and calculated dispersion curves. The performed calculations are strongly related to the implemented crystallographic data of each layer. Dispersion curves are found to be sensitive to the SAW propagation direction and the stratification process for the explored frequency ranges 50-250 MHz, even though it corresponds to a wave length clearly higher than the whole films thickness.

  20. Surface Acoustic Wave Based Pressure Sensor with Ground Shielding over Cavity on 41° YX LiNbO3

    NASA Astrophysics Data System (ADS)

    Lee, Keekeun; Wang, Wen; Kim, Geunyoung; Yang, Sangsik

    2006-07-01

    A surface acoustic wave (SAW)-based pressure sensor was fabricated for stable mechanical compression force measurement. A single phase unidirectional transducer (SPUDT) and two acoustic tracks were employed to minimize inherent insertion loss and improve reflectivity from the reflectors. The coupling of modes (COM) theory and finite element methods (FEMs) were used to determine optimal design parameters. A LiNbO3 diaphragm was bonded to a heavily doped silicon substrate with a cavity of ˜250 μm deep, in which gold was lined all over the inner cavity to reduce the coupling loss of SAW energy to the surrounding atmosphere. As a mechanical compression force was applied to the diaphragm, the diaphragm bent, resulting in phase shifts of the reflected peaks. The phase shifts were modulated depending on the amount of mechanical compression applied. The measured reflection coefficient S11 showed good agreement with simulated results.

  1. Effect of Forcing Function on Nonlinear Acoustic Standing Waves

    NASA Technical Reports Server (NTRS)

    Finkheiner, Joshua R.; Li, Xiao-Fan; Raman, Ganesh; Daniels, Chris; Steinetz, Bruce

    2003-01-01

    Nonlinear acoustic standing waves of high amplitude have been demonstrated by utilizing the effects of resonator shape to prevent the pressure waves from entering saturation. Experimentally, nonlinear acoustic standing waves have been generated by shaking an entire resonating cavity. While this promotes more efficient energy transfer than a piston-driven resonator, it also introduces complicated structural dynamics into the system. Experiments have shown that these dynamics result in resonator forcing functions comprised of a sum of several Fourier modes. However, previous numerical studies of the acoustics generated within the resonator assumed simple sinusoidal waves as the driving force. Using a previously developed numerical code, this paper demonstrates the effects of using a forcing function constructed with a series of harmonic sinusoidal waves on resonating cavities. From these results, a method will be demonstrated which allows the direct numerical analysis of experimentally generated nonlinear acoustic waves in resonators driven by harmonic forcing functions.

  2. Ion-acoustic cnoidal waves in a quantum plasma

    SciTech Connect

    Mahmood, S.; Haas, F.

    2014-10-15

    Nonlinear ion-acoustic cnoidal wave structures are studied in an unmagnetized quantum plasma. Using the reductive perturbation method, a Korteweg-de Vries equation is derived for appropriate boundary conditions and nonlinear periodic wave solutions are obtained. The corresponding analytical solution and numerical plots of the ion-acoustic cnoidal waves and solitons in the phase plane are presented using the Sagdeev pseudo-potential approach. The variations in the nonlinear potential of the ion-acoustic cnoidal waves are studied at different values of quantum parameter H{sub e} which is the ratio of electron plasmon energy to electron Fermi energy defined for degenerate electrons. It is found that both compressive and rarefactive ion-acoustic cnoidal wave structures are formed depending on the value of the quantum parameter. The dependence of the wavelength and frequency on nonlinear wave amplitude is also presented.

  3. Standing surface acoustic wave based cell coculture.

    PubMed

    Li, Sixing; Guo, Feng; Chen, Yuchao; Ding, Xiaoyun; Li, Peng; Wang, Lin; Cameron, Craig E; Huang, Tony Jun

    2014-10-07

    Precise reconstruction of heterotypic cell-cell interactions in vitro requires the coculture of different cell types in a highly controlled manner. In this article, we report a standing surface acoustic wave (SSAW)-based cell coculture platform. In our approach, different types of cells are patterned sequentially in the SSAW field to form an organized cell coculture. To validate our platform, we demonstrate a coculture of epithelial cancer cells and endothelial cells. Real-time monitoring of cell migration dynamics reveals increased cancer cell mobility when cancer cells are cocultured with endothelial cells. Our SSAW-based cell coculture platform has the advantages of contactless cell manipulation, high biocompatibility, high controllability, simplicity, and minimal interference of the cellular microenvironment. The SSAW technique demonstrated here can be a valuable analytical tool for various biological studies involving heterotypic cell-cell interactions.

  4. Standing Surface Acoustic Wave Based Cell Coculture

    PubMed Central

    2015-01-01

    Precise reconstruction of heterotypic cell–cell interactions in vitro requires the coculture of different cell types in a highly controlled manner. In this article, we report a standing surface acoustic wave (SSAW)-based cell coculture platform. In our approach, different types of cells are patterned sequentially in the SSAW field to form an organized cell coculture. To validate our platform, we demonstrate a coculture of epithelial cancer cells and endothelial cells. Real-time monitoring of cell migration dynamics reveals increased cancer cell mobility when cancer cells are cocultured with endothelial cells. Our SSAW-based cell coculture platform has the advantages of contactless cell manipulation, high biocompatibility, high controllability, simplicity, and minimal interference of the cellular microenvironment. The SSAW technique demonstrated here can be a valuable analytical tool for various biological studies involving heterotypic cell–cell interactions. PMID:25232648

  5. Ionospheric acoustic and gravity waves associated with midlatitude thunderstorms

    SciTech Connect

    Lay, Erin H.; Shao, Xuan -Min; Kendrick, Alexander K.; Carrano, Charles S.

    2015-07-30

    Acoustic waves with periods of 2–4 min and gravity waves with periods of 6–16 min have been detected at ionospheric heights (25–350 km) using GPS total electron content measurements. The area disturbed by these waves and the wave amplitudes have been associated with underlying thunderstorm activity. A statistical study comparing Next Generation Weather Radar thunderstorm measurements with ionospheric acoustic and gravity waves in the midlatitude U.S. Great Plains region was performed for the time period of May–July 2005. An increase of ionospheric acoustic wave disturbed area and amplitude is primarily associated with large thunderstorms (mesoscale convective systems). Ionospheric gravity wave disturbed area and amplitude scale with thunderstorm activity, with even small storms (i.e., individual storm cells) producing an increase of gravity waves.

  6. Ionospheric acoustic and gravity waves associated with midlatitude thunderstorms

    NASA Astrophysics Data System (ADS)

    Lay, Erin H.; Shao, Xuan-Min; Kendrick, Alexander K.; Carrano, Charles S.

    2015-07-01

    Acoustic waves with periods of 2-4 min and gravity waves with periods of 6-16 min have been detected at ionospheric heights (250-350 km) using GPS total electron content measurements. The area disturbed by these waves and the wave amplitudes have been associated with underlying thunderstorm activity. A statistical study comparing Next Generation Weather Radar thunderstorm measurements with ionospheric acoustic and gravity waves in the midlatitude U.S. Great Plains region was performed for the time period of May-July 2005. An increase of ionospheric acoustic wave disturbed area and amplitude is primarily associated with large thunderstorms (mesoscale convective systems). Ionospheric gravity wave disturbed area and amplitude scale with thunderstorm activity, with even small storms (i.e., individual storm cells) producing an increase of gravity waves.

  7. Strongly driven ion acoustic waves in laser produced plasmas

    SciTech Connect

    Baldis, H.A.; Labaune, C.; Renard, N.

    1994-09-20

    This paper present an experimental study of ion acoustic waves with wavenumbers corresponding to stimulated Brillouin scattering. Time resolved Thomson scattering in frequency and wavenumber space, has permitted to observe the dispersion relation of the waves as a function of the laser intensity. Apart from observing ion acoustic waves associated with a strong second component is observed at laser intensities above 10{sup 13}Wcm{sup {minus}2}.

  8. Implementing wavelet inverse-transform processor with surface acoustic wave device.

    PubMed

    Lu, Wenke; Zhu, Changchun; Liu, Qinghong; Zhang, Jingduan

    2013-02-01

    The objective of this research was to investigate the implementation schemes of the wavelet inverse-transform processor using surface acoustic wave (SAW) device, the length function of defining the electrodes, and the possibility of solving the load resistance and the internal resistance for the wavelet inverse-transform processor using SAW device. In this paper, we investigate the implementation schemes of the wavelet inverse-transform processor using SAW device. In the implementation scheme that the input interdigital transducer (IDT) and output IDT stand in a line, because the electrode-overlap envelope of the input IDT is identical with the one of the output IDT (i.e. the two transducers are identical), the product of the input IDT's frequency response and the output IDT's frequency response can be implemented, so that the wavelet inverse-transform processor can be fabricated. X-112(0)Y LiTaO(3) is used as a substrate material to fabricate the wavelet inverse-transform processor. The size of the wavelet inverse-transform processor using this implementation scheme is small, so its cost is low. First, according to the envelope function of the wavelet function, the length function of the electrodes is defined, then, the lengths of the electrodes can be calculated from the length function of the electrodes, finally, the input IDT and output IDT can be designed according to the lengths and widths for the electrodes. In this paper, we also present the load resistance and the internal resistance as the two problems of the wavelet inverse-transform processor using SAW devices. The solutions to these problems are achieved in this study. When the amplifiers are subjected to the input end and output end for the wavelet inverse-transform processor, they can eliminate the influence of the load resistance and the internal resistance on the output voltage of the wavelet inverse-transform processor using SAW device.

  9. Development of a new surface acoustic wave based gyroscope on a X-112°Y LiTaO3 substrate.

    PubMed

    Wang, Wen; Liu, Jiuling; Xie, Xiao; Liu, Minghua; He, Shitang

    2011-01-01

    A new micro gyroscope based on the surface acoustic wave (SAW) gyroscopic effect was developed. The SAW gyroscopic effect is investigated by applying the surface effective permittivity method in the regime of small ratios of the rotation velocity and the frequency of the SAW. The theoretical analysis indicates that the larger velocity shift was observed from the rotated X-112°Y LiTaO3 substrate. Then, two SAW delay lines with reverse direction and an operation frequency of 160 MHz are fabricated on a same X-112°Y LiTaO3 chip as the feedback of two SAW oscillators, which act as the sensor element. The single-phase unidirectional transducer (SPUDT) and combed transducers were used to structure the delay lines to improve the frequency stability of the oscillator. The rotation of a piezoelectric medium gives rise to a shift of the propagation velocity of SAW due to the Coriolis force, resulting in the frequency shift of the SAW device, and hence, the evaluation of the sensor performance. Meanwhile, the differential structure was performed to double the sensitivity and compensate for the temperature effects. Using a precise rate table, the performance of the fabricated SAW gyroscope was evaluated experimentally. A sensitivity of 1.332 Hz deg(-1) s at angular rates of up to 1,000 deg s(-1) and good linearity are observed.

  10. Reverberant Acoustic Testing and Direct Field Acoustic Testing Acoustic Standing Waves and their Impact on Structural Responses

    NASA Technical Reports Server (NTRS)

    Kolaini, Ali R.; Doty, Benjamin; Chang, Zensheu

    2012-01-01

    The aerospace industry has been using two methods of acoustic testing to qualify flight hardware: (1) Reverberant Acoustic Test (RAT), (2) Direct Field Acoustic Test (DFAT). The acoustic field obtained by RAT is generally understood and assumed to be diffuse, expect below Schroeder cut-of frequencies. DFAT method of testing has some distinct advantages over RAT, however the acoustic field characteristics can be strongly affected by test setup such as the speaker layouts, number and location of control microphones and control schemes. In this paper the following are discussed based on DEMO tests performed at APL and JPL: (1) Acoustic wave interference patterns and acoustic standing waves, (2) The structural responses in RAT and DFAT.

  11. Separation of Escherichia coli bacteria from peripheral blood mononuclear cells using standing surface acoustic waves.

    PubMed

    Ai, Ye; Sanders, Claire K; Marrone, Babetta L

    2013-10-01

    A microfluidic device was developed to separate heterogeneous particle or cell mixtures in a continuous flow using acoustophoresis. In this device, two identical surface acoustic waves (SAWs) generated by interdigital transducers (IDTs) propagated toward a microchannel, which accordingly built up a standing surface acoustic wave (SSAW) field across the channel. A numerical model, coupling a piezoelectric effect in the solid substrate and acoustic pressure in the fluid, was developed to provide a better understanding of SSAW-based particle manipulation. It was found that the pressure nodes across the channel were individual planes perpendicular to the solid substrate. In the separation experiments, two side sheath flows hydrodynamically focused the injected particle or cell mixtures into a very narrow stream along the centerline. Particles flowing through the SSAW field experienced an acoustic radiation force that highly depends on the particle properties. As a result, dissimilar particles or cells were laterally attracted toward the pressure nodes at different magnitudes, and were eventually switched to different outlets. Two types of fluorescent microspheres with different sizes were successfully separated using the developed device. In addition, Escherichia coli bacteria premixed in peripheral blood mononuclear cells (PBMCs) were also efficiently isolated using the SSAW-base separation technique. Flow cytometric analysis on the collected samples found that the purity of separated E. coli bacteria was 95.65%.

  12. Multiple-frequency acoustic wave devices for chemical sensing and materials characterization in both gas and liquid phase

    DOEpatents

    Martin, Stephen J.; Ricco, Antonio J.

    1993-01-01

    A chemical sensor (1) includes two or more pairs of interdigital electrodes (10) having different periodicities. Each pair is comprised of a first electrode (10a) and a second electrode (10b). The electrodes are patterned on a surface of a piezoelectric substrate (12). Each pair of electrodes may launch and receive various acoustic waves (AW), including a surface acoustic wave (SAW), and may also launch and receive several acoustic plate modes (APMs). The frequencies associated with each are functions of the transducer periodicity as well as the velocity of the particular AW in the chosen substrate material. An AW interaction region (13) exists between each pair of electrodes. Circuitry (20, 40) is used to launch, receive, and monitor the propagation characteristics of the AWs and may be configured in an intermittent measurement fashion or in a continuous measurement fashion. Perturbations to the AW velocity and attenuation are recorded at several frequencies and provide the sensor response.

  13. Theoretical and experimental study on the acoustic wave energy after the nonlinear interaction of acoustic waves in aqueous media

    NASA Astrophysics Data System (ADS)

    Lan, Chao-feng; Li, Feng-chen; Chen, Huan; Lu, Di; Yang, De-sen; Zhang, Meng

    2015-06-01

    Based on the Burgers equation and Manley-Rowe equation, the derivation about nonlinear interaction of the acoustic waves has been done in this paper. After nonlinear interaction among the low-frequency weak waves and the pump wave, the analytical solutions of acoustic waves' amplitude in the field are deduced. The relationship between normalized energy of high-frequency and the change of acoustic energy before and after the nonlinear interaction of the acoustic waves is analyzed. The experimental results about the changes of the acoustic energy are presented. The study shows that new frequencies are generated and the energies of the low-frequency are modulated in a long term by the pump waves, which leads the energies of the low-frequency acoustic waves to change in the pulse trend in the process of the nonlinear interaction of the acoustic waves. The increase and decrease of the energies of the low-frequency are observed under certain typical conditions, which lays a foundation for practical engineering applications.

  14. Ionospheric acoustic and gravity waves associated with midlatitude thunderstorms

    DOE PAGES

    Lay, Erin H.; Shao, Xuan -Min; Kendrick, Alexander K.; ...

    2015-07-30

    Acoustic waves with periods of 2–4 min and gravity waves with periods of 6–16 min have been detected at ionospheric heights (25–350 km) using GPS total electron content measurements. The area disturbed by these waves and the wave amplitudes have been associated with underlying thunderstorm activity. A statistical study comparing Next Generation Weather Radar thunderstorm measurements with ionospheric acoustic and gravity waves in the midlatitude U.S. Great Plains region was performed for the time period of May–July 2005. An increase of ionospheric acoustic wave disturbed area and amplitude is primarily associated with large thunderstorms (mesoscale convective systems). Ionospheric gravity wavemore » disturbed area and amplitude scale with thunderstorm activity, with even small storms (i.e., individual storm cells) producing an increase of gravity waves.« less

  15. Relationship between dust acoustic waves in two and three dimensions

    SciTech Connect

    Piel, A.; Goree, J.

    2006-10-15

    Low frequency electrostatic waves are investigated for a monolayer suspension of dust particles that are shielded by an ambient plasma of three-dimensional extension. The dispersion of the resulting dust acoustic surface waves is compared with dust acoustic waves in three dimensions and with lattice modes in two dimensions. It is found that the wave dispersion is determined by shielding of electric fields by electrons and ions on either side of the dust monolayer; this differs from previously studied cases of charged sheets in a vacuum. The phase velocity of these surface waves suggests the definition of a proper dust plasma frequency for monolayer systems.

  16. Microfluidic pumps employing surface acoustic waves generated in ZnO thin films

    SciTech Connect

    Du, X. Y.; Flewitt, A. J.; Milne, W. I.; Fu, Y. Q.; Luo, J. K.

    2009-01-15

    ZnO thin film based surface acoustic wave (SAW) devices have been utilized to fabricate microfluidic pumps. The SAW devices were fabricated on nanocrystalline ZnO piezoelectric thin films deposited on Si substrates using rf magnetron sputtering and use a Sezawa wave mode for effective droplet motion. The as-deposited ZnO surface is hydrophilic, with a water contact angle of {approx}75 deg., which prevents droplet pumping. Therefore, the ZnO surface was coated using a self-assembled monolayer of octadecyltrichlorosilane which forms a hydrophobic surface with a water contact angle of {approx}110 deg. Liquid droplets between 0.5 and 1 {mu}l in volume were successfully pumped on the hydrophobic ZnO surface at velocities up to 1 cm s{sup -1}. Under acoustic pressure, the water droplet on an hydrophilic surface becomes deformed, and the asymmetry in the contact angle at the trailing and leading edges allow the force acting upon the droplet to be calculated. These forces, which increase with input voltage above a threshold level, are found to be in the range of {approx}100 {mu}N. A pulsed rf signal has also been used to demonstrate precision manipulation of the liquid droplets. Furthermore, a SAW device structure is demonstrated in which the ZnO piezoelectric only exists under the input and output transducers. This structure still permits pumping, while avoiding direct contact between the piezoelectric material and the fluid. This is of particular importance for biological laboratory-on-a-chip applications.

  17. Creating and studying ion acoustic waves in ultracold neutral plasmas

    SciTech Connect

    Killian, T. C.; Castro, J.; McQuillen, P.; O'Neil, T. M.

    2012-05-15

    We excite ion acoustic waves in ultracold neutral plasmas by imprinting density modulations during plasma creation. Laser-induced fluorescence is used to observe the density and velocity perturbations created by the waves. The effect of expansion of the plasma on the evolution of the wave amplitude is described by treating the wave action as an adiabatic invariant. After accounting for this effect, we determine that the waves are weakly damped, but the damping is significantly faster than expected for Landau damping.

  18. Propagation of waves of acoustic frequencies in curved ducts

    NASA Technical Reports Server (NTRS)

    Rostafinski, W.

    1973-01-01

    The propagation of waves of acoustic frequencies in curved ducts is studied for the first four modes. The analysis makes use of Bessel functions to construct curves of wave number in the duct versus imposed wave number. The results apply to ducts of arbitrary width and arbitrary radii of curvature. The characteristics of motion in a bend are compared with propagation of waves in a straight duct, and important differences in the behavior of waves are noted.

  19. Study of X-ray diffraction from a surface acoustic wave in the grazing geometry with allowance for the curvature of the unperturbed crystal surface

    SciTech Connect

    Mkrtchyan, A. R. Kocharyan, V. R.; Levonyan, L. V.; Khachaturyan, G. K.

    2006-12-15

    Fresnel X-ray diffraction from a concave crystal surface in the presence of a surface acoustic wave (SAW) has been considered for grazing angles of incidence in noncoplanar symmetric Laue geometry. It is shown that the main peak and diffraction satellites are focused at different distances from a crystal. The effect of deviation from the Bragg angle, the spectral line width, and the SAW amplitude on the X-ray diffraction pattern has been analyzed. It is established that the contrast of an X-ray diffraction pattern of an SAW in Bragg-Laue grazing geometry is related to the character of irregularities of the crystal surface, and the pattern details depend on the measurement mode. The sensitivity of the method is about a nanometer. The focal image of the SAW serves as a scale landmark for determining the crystal surface characteristics.

  20. False Paradoxes of Superposition in Electric and Acoustic Waves.

    ERIC Educational Resources Information Center

    Levine, Richard C.

    1980-01-01

    Corrected are several misconceptions concerning the apparently "missing" energy that results when acoustic or electromagnetic waves cancel by destructive interference and the wave impedance reflected to the sources of the wave energy changes so that the input power is reduced. (Author/CS)

  1. Self-focusing of ion-acoustic surface waves

    NASA Astrophysics Data System (ADS)

    Stenflo, L.; Gradov, O. M.

    1996-06-01

    An electrostatic ion-acoustic surface wave propagating along the boundary of a semi-infinite plasma is considered. It is shown that a nonlinear Schrödinger equation can describe the development of the wave amplitude. The self-focusing length of a wave beam is estimated.

  2. Waveform inversion of acoustic waves for explosion yield estimation

    SciTech Connect

    Kim, K.; Rodgers, A. J.

    2016-07-08

    We present a new waveform inversion technique to estimate the energy of near-surface explosions using atmospheric acoustic waves. Conventional methods often employ air blast models based on a homogeneous atmosphere, where the acoustic wave propagation effects (e.g., refraction and diffraction) are not taken into account, and therefore, their accuracy decreases with increasing source-receiver distance. In this study, three-dimensional acoustic simulations are performed with a finite difference method in realistic atmospheres and topography, and the modeled acoustic Green's functions are incorporated into the waveform inversion for the acoustic source time functions. The strength of the acoustic source is related to explosion yield based on a standard air blast model. The technique was applied to local explosions (<10 km) and provided reasonable yield estimates (<~30% error) in the presence of realistic topography and atmospheric structure. In conclusion, the presented method can be extended to explosions recorded at far distance provided proper meteorological specifications.

  3. High-Speed Transport of Fluid Drops and Solid Particles via Surface Acoustic Waves

    NASA Technical Reports Server (NTRS)

    Bar-Cohen, Yoseph; Bao, Xiaoqi; Sherrit, Stewart; Badescu, Mircea; Lih, Shyh-shiuh

    2012-01-01

    A compact sampling tool mechanism that can operate at various temperatures, and transport and sieve particle sizes of powdered cuttings and soil grains with no moving parts, has been created using traveling surface acoustic waves (SAWs) that are emitted by an inter-digital transducer (IDT). The generated waves are driven at about 10 MHz, and it causes powder to move towards the IDT at high speed with different speeds for different sizes of particles, which enables these particles to be sieved. This design is based on the use of SAWs and their propelling effect on powder particles and fluids along the path of the waves. Generally, SAWs are elastic waves propagating in a shallow layer of about one wavelength beneath the surface of a solid substrate. To generate SAWs, a piezoelectric plate is used that is made of LiNbO3 crystal cut along the x-axis with rotation of 127.8 along the y-axis. On this plate are printed pairs of fingerlike electrodes in the form of a grating that are activated by subjecting the gap between the electrodes to electric field. This configuration of a surface wave transmitter is called IDT. The IDT that was used consists of 20 pairs of fingers with 0.4-mm spacing, a total length of 12.5 mm. The surface wave is produced by the nature of piezoelectric material to contract or expand when subjected to an electric field. Driving the IDT to generate wave at high amplitudes provides an actuation mechanism where the surface particles move elliptically, pulling powder particles on the surface toward the wavesource and pushing liquids in the opposite direction. This behavior allows the innovation to separate large particles and fluids that are mixed. Fluids are removed at speed (7.5 to 15 cm/s), enabling this innovation of acting as a bladeless wiper for raindrops. For the windshield design, the electrodes could be made transparent so that they do not disturb the driver or pilot. Multiple IDTs can be synchronized to transport water or powder over larger

  4. Rapid determination of floral aroma compounds of lilac blossom by fast gas chromatography combined with surface acoustic wave sensor.

    PubMed

    Oh, Se Yeon; Shin, Hyun Du; Kim, Sung Jean; Hong, Jongki

    2008-03-07

    A novel analytical method using fast gas chromatography combined with surface acoustic wave sensor (GC/SAW) has been developed for the detection of volatile aroma compounds emanated from lilac blossom (Syringa species: Syringa vulgaris variginata and Syringa dilatata). GC/SAW could detect and quantify various fragrance emitted from lilac blossom, enabling to provide fragrance pattern analysis results. The fragrance pattern analysis could easily characterize the delicate differences in aromas caused by the substantial difference of chemical composition according to different color and shape of petals. Moreover, the method validation of GC/SAW was performed for the purpose of volatile floral actual aroma analysis, achieving a high reproducibility and excellent sensitivity. From the validation results, GC/SAW could serve as an alternative analytical technique for the analysis of volatile floral actual aroma of lilac. In addition, headspace solid-phase microextraction (HS-SPME) GC-MS was employed to further confirm the identification of fragrances emitted from lilac blossom and compared to GC/SAW.

  5. Mass Sensitivity Optimization of a Surface Acoustic Wave Sensor Incorporating a Resonator Configuration

    PubMed Central

    Hao, Wenchang; Liu, Jiuling; Liu, Minghua; Liang, Yong; He, Shitang

    2016-01-01

    The effect of the sensitive area of the two-port resonator configuration on the mass sensitivity of a Rayleigh surface acoustic wave (R-SAW) sensor was investigated theoretically, and verified in experiments. A theoretical model utilizing a 3-dimensional finite element method (FEM) approach was established to extract the coupling-of-modes (COM) parameters in the absence and presence of mass loading covering the electrode structures. The COM model was used to simulate the frequency response of an R-SAW resonator by a P-matrix cascading technique. Cascading the P-matrixes of unloaded areas with mass loaded areas, the sensitivity for different sensitive areas was obtained by analyzing the frequency shift. The performance of the sensitivity analysis was confirmed by the measured responses from the silicon dioxide (SiO2) deposited on different sensitive areas of R-SAW resonators. It is shown that the mass sensitivity varies strongly for different sensitive areas, and the optimal sensitive area lies towards the center of the device. PMID:27104540

  6. Mass Sensitivity Optimization of a Surface Acoustic Wave Sensor Incorporating a Resonator Configuration.

    PubMed

    Hao, Wenchang; Liu, Jiuling; Liu, Minghua; Liang, Yong; He, Shitang

    2016-04-20

    The effect of the sensitive area of the two-port resonator configuration on the mass sensitivity of a Rayleigh surface acoustic wave (R-SAW) sensor was investigated theoretically, and verified in experiments. A theoretical model utilizing a 3-dimensional finite element method (FEM) approach was established to extract the coupling-of-modes (COM) parameters in the absence and presence of mass loading covering the electrode structures. The COM model was used to simulate the frequency response of an R-SAW resonator by a P-matrix cascading technique. Cascading the P-matrixes of unloaded areas with mass loaded areas, the sensitivity for different sensitive areas was obtained by analyzing the frequency shift. The performance of the sensitivity analysis was confirmed by the measured responses from the silicon dioxide (SiO₂) deposited on different sensitive areas of R-SAW resonators. It is shown that the mass sensitivity varies strongly for different sensitive areas, and the optimal sensitive area lies towards the center of the device.

  7. Transparent ZnO/glass surface acoustic wave based high performance ultraviolet light sensors

    NASA Astrophysics Data System (ADS)

    Wang, Wen-Bo; Gu, Hang; He, Xing-Li; Xuan, Wei-Peng; Chen, Jin-Kai; Wang, Xiao-Zhi; Luo, Ji-Kui

    2015-05-01

    Surface acoustic wave (SAW) resonators are a type of ultraviolet (UV) light sensors with high sensitivity, and they have been extensively studied. Transparent SAW devices are very useful and can be developed into various sensors and microfluidics for sensing/monitoring and lab-on-chip applications. We report the fabrication of high sensitivity SAW UV sensors based on piezoelectric (PE) ZnO thin films deposited on glass substrates. The sensors were fabricated and their performances against the post-deposition annealing condition were investigated. It was found that the UV-light sensitivity is improved by more than one order of magnitude after annealing. The frequency response increases significantly and the response becomes much faster. The optimized devices also show a small temperature coefficient of frequency and excellent repeatability and stability, demonstrating its potential for UV-light sensing application. Project supported by the National Natural Science Foundation of China (Grant Nos. 61274037 and 61301046) and the Research Fund for the Doctoral Program of Higher Education of China (Grant Nos. 20120101110031 and 20120101110054).

  8. Surface acoustic wave amplification by direct current-voltage supplied to graphene film

    SciTech Connect

    Insepov, Z.; Emelin, E.; Kononenko, O.; Roshchupkin, D. V.; Tnyshtykbayev, K. B.; Baigarin, K. A.

    2015-01-12

    Using a high-resolution X-Ray diffraction measurement method, the surface acoustic wave (SAW) propagation in a graphene film on the surface of a Ca{sub 3}TaGa{sub 3}Si{sub 2}O{sub 14} (CTGS) piezoelectric crystal was investigated, where an external current was driven across the graphene film. Here, we show that the application of the DC field leads to a significant enhancement of the SAW magnitude and, as a result, to amplification of the diffraction satellites. Amplification of 33.2 dB/cm for the satellite +1, and of 13.8 dB/cm for the satellite +2, at 471 MHz has been observed where the external DC voltage of +10 V was applied. Amplification of SAW occurs above a DC field much smaller than that of a system using bulk semiconductor. Theoretical estimates are in reasonable agreement with our measurements and analysis of experimental data for other materials.

  9. Detecting trihalomethanes using nanoporous-carbon coated surface-acoustic-wave sensors

    DOE PAGES

    Siegal, Michael P.; Mowry, Curtis D.; Pfeifer, Kent B.; ...

    2015-03-07

    We study nanoporous-carbon (NPC) grown via pulsed laser deposition (PLD) as a sorbent coating on 96.5-MHz surface-acoustic-wave (SAW) devices to detect trihalomethanes (THMs), regulated byproducts from the chemical treatment of drinking water. Using both insertion-loss and isothermal-response measurements from known quantities of chloroform, the highest vapor pressure THM, we optimize the NPC mass-density at 1.05 ± 0.08 g/cm3 by controlling the background argon pressure during PLD. Precise THM quantities in a chlorobenzene solvent are directly injected into a separation column and detected as the phase-angle shift of the SAW device output compared to the drive signal. Using optimized NPC-coated SAWs,more » we study the chloroform response as a function of operating temperatures ranging from 10–50°C. Finally, we demonstrate individual responses from complex mixtures of all four THMs, with masses ranging from 10–2000 ng, after gas chromatography separation. As a result, estimates for each THM detection limit using a simple peak-height response evaluation are 4.4 ng for chloroform and 1 ng for bromoform; using an integrated-peak area response analysis improves the detection limits to 0.73 ng for chloroform and 0.003 ng bromoform.« less

  10. Rapid generation of protein aerosols and nanoparticles via surface acoustic wave atomization

    NASA Astrophysics Data System (ADS)

    Alvarez, Mar; Friend, James; Yeo, Leslie Y.

    2008-11-01

    We describe the fabrication of a surface acoustic wave (SAW) atomizer and show its ability to generate monodisperse aerosols and particles for drug delivery applications. In particular, we demonstrate the generation of insulin liquid aerosols for pulmonary delivery and solid protein nanoparticles for transdermal and gastrointestinal delivery routes using 20 MHz SAW devices. Insulin droplets around 3 µm were obtained, matching the optimum range for maximizing absorption in the alveolar region. A new approach is provided to explain these atomized droplet diameters by returning to fundamental physical analysis and considering viscous-capillary and inertial-capillary force balance rather than employing modifications to the Kelvin equation under the assumption of parametric forcing that has been extended to these frequencies in past investigations. In addition, we consider possible mechanisms by which the droplet ejections take place with the aid of high-speed flow visualization. Finally, we show that nanoscale protein particles (50-100 nm in diameter) were obtained through an evaporative process of the initial aerosol, the final size of which could be controlled merely by modifying the initial protein concentration. These results illustrate the feasibility of using SAW as a novel method for rapidly producing particles and droplets with a controlled and narrow size distribution.

  11. Detecting trihalomethanes using nanoporous-carbon coated surface-acoustic-wave sensors

    SciTech Connect

    Siegal, Michael P.; Mowry, Curtis D.; Pfeifer, Kent B.; Gallis, Dorina F. S.

    2015-03-07

    We study nanoporous-carbon (NPC) grown via pulsed laser deposition (PLD) as a sorbent coating on 96.5-MHz surface-acoustic-wave (SAW) devices to detect trihalomethanes (THMs), regulated byproducts from the chemical treatment of drinking water. Using both insertion-loss and isothermal-response measurements from known quantities of chloroform, the highest vapor pressure THM, we optimize the NPC mass-density at 1.05 ± 0.08 g/cm3 by controlling the background argon pressure during PLD. Precise THM quantities in a chlorobenzene solvent are directly injected into a separation column and detected as the phase-angle shift of the SAW device output compared to the drive signal. Using optimized NPC-coated SAWs, we study the chloroform response as a function of operating temperatures ranging from 10–50°C. Finally, we demonstrate individual responses from complex mixtures of all four THMs, with masses ranging from 10–2000 ng, after gas chromatography separation. As a result, estimates for each THM detection limit using a simple peak-height response evaluation are 4.4 ng for chloroform and 1 ng for bromoform; using an integrated-peak area response analysis improves the detection limits to 0.73 ng for chloroform and 0.003 ng bromoform.

  12. Effect of acoustic field parameters on arc acoustic binding during ultrasonic wave-assisted arc welding.

    PubMed

    Xie, Weifeng; Fan, Chenglei; Yang, Chunli; Lin, Sanbao

    2016-03-01

    As a newly developed arc welding method, power ultrasound has been successfully introduced into arc and weld pool during ultrasonic wave-assisted arc welding process. The advanced process for molten metals can be realized by utilizing additional ultrasonic field. Under the action of the acoustic wave, the plasma arc as weld heat source is regulated and its characteristics make an obvious change. Compared with the conventional arc, the ultrasonic wave-assisted arc plasma is bound significantly and becomes brighter. To reveal the dependence of the acoustic binding force on acoustic field parameters, a two-dimensional acoustic field model for ultrasonic wave-assisted arc welding device is established. The influences of the radiator height, the central pore radius, the radiator radius, and curvature radius or depth of concave radiator surface are discussed using the boundary element method. Then the authors analyze the resonant mode by this relationship curve between acoustic radiation power and radiator height. Furthermore, the best acoustic binding ability is obtained by optimizing the geometric parameters of acoustic radiator. In addition, three concave radiator surfaces including spherical cap surface, paraboloid of revolution, and rotating single curved surface are investigated systematically. Finally, both the calculation and experiment suggest that, to obtain the best acoustic binding ability, the ultrasonic wave-assisted arc welding setup should be operated under the first resonant mode using a radiator with a spherical cap surface, a small central pore, a large section radius and an appropriate curvature radius.

  13. Surface acoustic waves in two dimensional phononic crystal with anisotropic inclusions

    NASA Astrophysics Data System (ADS)

    Ketata, H.; Hédi Ben Ghozlen, M.

    2012-06-01

    An analysis is given to the band structure of the two dimensional solid phononic crystal considered as a semi infinite medium. The lattice includes an array of elastic anisotropic materials with different shapes embedded in a uniform matrix. For illustration two kinds of phononic materials are assumed. A particular attention is devoted to the computational procedure which is mainly based on the plane wave expansion (PWE) method. It has been adapted to Matlab environment. Numerical calculations of the dispersion curves have been achieved by introducing particular functions which transform motion equations into an Eigen value problem. Significant improvements are obtained by increasing reasonably the number of Fourier components even when a large elastic mismatch is assumed. Such approach can be generalized to different types of symmetry and permit new physical properties as piezoelectricity to be added. The actual semi infinite phononic structure with a free surface has been shown to support surface acoustic waves (SAW). The obtained dispersion curves reveal band gaps in the SAW branches. It has been found that the influence, of the filling factor and anisotropy on their band gaps, is different from that of bulk waves.

  14. Broadband enhanced transmission of acoustic waves through serrated metal gratings

    NASA Astrophysics Data System (ADS)

    Qi, Dong-Xiang; Deng, Yu-Qiang; Xu, Di-Hu; Fan, Ren-Hao; Peng, Ru-Wen; Chen, Ze-Guo; Lu, Ming-Hui; Huang, X. R.; Wang, Mu

    2015-01-01

    In this letter, we have demonstrated that serrated metal gratings, which introduce gradient coatings, can give rise to broadband transmission enhancement of acoustic waves. Here, we have experimentally and theoretically studied the acoustic transmission properties of metal gratings with or without serrated boundaries. The average transmission is obviously enhanced for serrated metal gratings within a wide frequency range, while the Fabry-Perot resonance is significantly suppressed. An effective medium hypothesis with varying acoustic impedance is proposed to analyze the mechanism, which was verified through comparison with finite-element simulation. The serrated boundary supplies gradient mass distribution and gradient normal acoustic impedance, which could efficiently reduce the boundary reflection. Further, by increasing the region of the serrated boundary, we present a broadband high-transmission grating for wide range of incident angle. Our results may have potential applications to broadband acoustic imaging, acoustic sensing, and acoustic devices.

  15. SAW atomization application on inhaled pulmonary drug delivery

    NASA Astrophysics Data System (ADS)

    Qi, Aisha; Friend, James; Yeo, Leslie

    2008-12-01

    Pulmonary drug delivery transports the drug formulations directly to the respiratory tract in the form of inhaled particles or droplets. Because of the direct target treatment, it has significant advantages in the treatment of respiratory diseases, for example asthma. However, it is difficult to produce monodispersed particles/droplets in the 1-10 micron range, which is necessary for deposition in the targeted lung area or lower respiratory airways, in a controllable fashion. We demonstrate the use of surface acoustic waves (SAWs) as an efficient method for the generation of monodispersed micron dimension aerosols for the treatment of asthma. SAWs are ten nanometer order amplitude electroacoustic waves generated by applying an oscillating electric field to an interdigital transducer patterned on a piezoelectric substrate. The acoustic energy in the waves induces atomization of the working fluid, which contains a model drug, albuterol. Laser diffraction techniques employed to characterize the aerosols revealed mean diameter of the aerosol was around 3-4 μm. Parallel experiments employing a one-stage (glass) twin impinger as a lung model demonstrated a nearly 80% of atomized drug aerosol was deposited in the lung. The aerosol size distribution is relatively independent of the SAW frequency, which is consistent with our predictive scaling theory which accounts for the dominant balance between viscous and capillary stresses. Moreover, only 1-3 W powers consumption of SAW atomization suggests that the SAW atomizer can be miniaturized into dimensions commensurate with portable consumer devices.

  16. Scattering of Acoustic Waves from Ocean Boundaries

    DTIC Science & Technology

    2014-09-30

    derived reflection coefficients as a function of range along the reverberation track (right). RESULTS Analysis of Acoustic Scattering for Layered and... acoustic interaction with the ocean floor, including penetration through and reflection from smooth and rough water/sediment interfaces, scattering ...can account for the all of the physical processes and variability of acoustic propagation and scattering in ocean environments with special emphasis

  17. Wave-particle dynamics of wave breaking in the self-excited dust acoustic wave.

    PubMed

    Teng, Lee-Wen; Chang, Mei-Chu; Tseng, Yu-Ping; I, Lin

    2009-12-11

    The wave-particle microdynamics in the breaking of the self-excited dust acoustic wave growing in a dusty plasma liquid is investigated through directly tracking dust micromotion. It is found that the nonlinear wave growth and steepening stop as the mean oscillating amplitude of dust displacement reaches about 1/k (k is the wave number), where the vertical neighboring dust trajectories start to crossover and the resonant wave heating with uncertain crest trapping onsets. The dephased dust oscillations cause the abrupt dropping and broadening of the wave crest after breaking, accompanied by the transition from the liquid phase with coherent dust oscillation to the gas phase with chaotic dust oscillation. Corkscrew-shaped phase-space distributions measured at the fixed phases of the wave oscillation cycle clearly indicate how dusts move in and constitute the evolving waveform through dust-wave interaction.

  18. Mechanical Characterization of Nanoporous Thin Films by Nanoindentation and Laser-induced Surface Acoustic Waves

    NASA Astrophysics Data System (ADS)

    Chow, Gabriel

    Thin films represent a critical sector of modern engineering that strives to produce functional coatings at the smallest possible length scales. They appear most commonly in semiconductors where they form the foundation of all electronic circuits, but exist in many other areas to provide mechanical, electrical, chemical, and optical properties. The mechanical characterization of thin films has been a continued challenge due foremost to the length scales involved. However, emerging thin films focusing on materials with significant porosity, complex morphologies, and nanostructured surfaces produce additional difficulties towards mechanical analysis. Nanoindentation has been the dominant thin film mechanical characterization technique for the last decade because of the quick results, wide range of sample applicability, and ease of sample preparation. However, the traditional nanoindentation technique encounters difficulties for thin porous films. For such materials, alternative means of analysis are desirable and the lesser known laser-induced surface acoustic wave technique (LiSAW) shows great potential in this area. This dissertation focuses on studying thin, porous, and nanostructured films by nanoindentation and LiSAW techniques in an effort to directly correlate the two methodologies and to test the limits and applicabilities of each technique on challenging media. The LiSAW technique is particularly useful for thin porous films because unlike indentation, the substrate is properly accounted for in the wave motion analysis and no plastic deformation is necessary. Additionally, the use of lasers for surface acoustic wave generation and detection allows the technique to be fully non-contact. This is desirable in the measurement of thin, delicate, and porous films where physical sample probing may not be feasible. The LiSAW technique is also valuable in overcoming nanoscale roughness, particularly for films that cannot be mechanically polished, since typical SAW

  19. Surface acoustic wave properties of proton-exchanged LiNbO3 waveguides with SiO2 film.

    PubMed

    Kao, Kuo-Sheng; Cheng, Chien-Chuan; Chung, Chung-Jen; Chen, Ying-Chung

    2005-03-01

    Surface acoustic wave (SAW) properties of proton-exchanged (PE) z-cut lithium niobate (LiNbO3) waveguides with silicon dioxide (SiO2) film layers were investigated using octanoic acid. The distribution of hydrogen measured by secondary ion mass spectrometry (SIMS) showed a step-like profile, which was assumed to be equal to the waveguide depth (d). The SiO2 film was deposited on z-cut LiNbO3 waveguide by radio frequency (rf) magnetron sputtering. We investigated the important parameters for the design of SAW devices such as phase velocity (Vp), insertion loss (IL) and temperature coefficient of frequency (TCF) by a network analyzer using thin-film aluminum interdigital transducer electrodes on the upper SiO2 film surface. The experimental results showed that the Vp of SAW decreased slightly with the increase of h/lambda, where h was the thickness of SiO2 films and lambda was the wavelength. The IL of SAW increased with increased h/lambda. The TCF of SAW calculated from the frequency change of the output of SAW delay line showed an evident decrease with the increase of h/lambda. The TCF for PE z-cut LiNbO3 was measured to be about -54.72 ppm/degreees C at h/lambda = 0.08. It revealed that the SiO2 films could compensate and improve the temperature stability as compared with the TCF of SAW on PE samples without SiO2 film.

  20. Spectral solution of acoustic wave-propagation problems

    NASA Technical Reports Server (NTRS)

    Kopriva, David A.

    1990-01-01

    The Chebyshev spectral collocation solution of acoustic wave propagation problems is considered. It is shown that the phase errors decay exponentially fast and that the number of points per wavelength is not sufficient to estimate the phase accuracy. Applications include linear propagation of a sinusoidal acoustic wavetrain in two space dimensions, and the interaction of a sound wave with the bow shock formed by placing a cylinder in a uniform Mach 4 supersonic free stream.

  1. Nonlinear Scattering of Acoustic Waves by Vibrating Obstacles.

    DTIC Science & Technology

    1983-06-01

    AD-A129 282 NONLINEAR SCATTERING OF ACOUSTIC WAVES BY VIBRATING OBSTACLES (U) NAVAL RESEARCH LAR WASHINOTON DC d C PIQUETTE 01 JUN 83 NRL-MR-5077...MICROCOPY RESOLUTION TEST CHART NAIOAL IBtJ[IAU Of S1ANDARD~If A3 NRL Memorandum Report 5077 Nonlinear Scattering of Acoustic Waves by Vibrating Obstacles ... Obstacles continuing problem. S. PERFORMING ORG. REPORT NUMMER 7. AUTHOR(s) 6. CONTRACT OR GRANT NUMIISER( ) Jean C. Piquette* S. PERFORMING

  2. Estimating propagation velocity through a surface acoustic wave sensor

    DOEpatents

    Xu, Wenyuan; Huizinga, John S.

    2010-03-16

    Techniques are described for estimating the propagation velocity through a surface acoustic wave sensor. In particular, techniques which measure and exploit a proper segment of phase frequency response of the surface acoustic wave sensor are described for use as a basis of bacterial detection by the sensor. As described, use of velocity estimation based on a proper segment of phase frequency response has advantages over conventional techniques that use phase shift as the basis for detection.

  3. Amplitude-weighted quadrature phase shift keying using SAW technology

    NASA Astrophysics Data System (ADS)

    Belkerdid, M. A.; Malocha, D. C.

    1985-09-01

    Surface acoustic wave (SAW) convolvers are capable of performing programmable matched filtering with the desirable properties of large processing gain, good dynamic range, broad bandwidth, small size and weight, and low power requirements. Equally powerful are the SAW-based modulators, which produce the desired pseudo-random code sequence for secure transmission in a spread-spectrum system. The SAW filter provides precise reproducible pulse shaping of the coded waveform with the same advantages of the convolver. It is very important as spectrum space becomes more crowded to optimize the spectral efficiency of transmitted information. Quadrature phase (QPSK) and minimum phase shift keying (MSK) are the two more popular quadrature modulation schemes. A new modulation technique that is composed of several amplitude-weighted QPSK signals (AWQPSK) and exhibits better bandwidth efficiency than OPSK or MSK is introduced. System analysis and performance parameters are presented for evaluation. A SAW modulator implementation is discussed and proposed.

  4. Frequency dependence of laser ultrasonic SAW phase velocities measurements.

    PubMed

    Li, Chunhui; Song, Shaozhen; Guan, Guangying; Wang, Ruikang K; Huang, Zhihong

    2013-01-01

    Advances in the field of laser ultrasonics have opened up new possibilities in applications in many areas. This paper verifies the relationship between phase velocities of different materials, including hard solid and soft solid, and the frequency range of SAW signal. We propose a novel approach that utilizes a low coherence interferometer to detect the laser-induced surface acoustic waves (SAWs). A Nd:YAG focused laser line-source is applied to steel, iron, plastic plates and a 3.5% agar-agar phantom. The generated SAW signals are detected by a time domain low coherence interferometry system. SAW phase velocity dispersion curves were calculated, from which the elasticity of the specimens was evaluated. The relationship between frequency content and phase velocities was analyzed. We show that the experimental results agreed well with those of the theoretical expectations.

  5. Effects of AlN Coating Layer on High Temperature Characteristics of Langasite SAW Sensors

    PubMed Central

    Shu, Lin; Peng, Bin; Cui, Yilin; Gong, Dongdong; Yang, Zhengbing; Liu, Xingzhao; Zhang, Wanli

    2016-01-01

    High temperature characteristics of langasite surface acoustic wave (SAW) devices coated with an AlN thin film have been investigated in this work. The AlN films were deposited on the prepared SAW devices by mid-frequency magnetron sputtering. The SAW devices coated with AlN films were measured from room temperature to 600 °C. The results show that the SAW devices can work up to 600 °C. The AlN coating layer can protect and improve the performance of the SAW devices at high temperature. The SAW velocity increases with increasing AlN coating layer thickness. The temperature coefficients of frequency (TCF) of the prepared SAW devices decrease with increasing thickness of AlN coating layers, while the electromechanical coupling coefficient (K2) of the SAW devices increases with increasing AlN film thickness. The K2 of the SAW devices increases by about 20% from room temperature to 600 °C. The results suggest that AlN coating layer can not only protect the SAW devices from environmental contamination, but also improve the K2 of the SAW devices. PMID:27608027

  6. Acoustic waves in gases with strong pressure gradients

    NASA Technical Reports Server (NTRS)

    Zorumski, William E.

    1989-01-01

    The effect of strong pressure gradients on the acoustic modes (standing waves) of a rectangular cavity is investigated analytically. When the cavity response is represented by a sum of modes, each mode is found to have two resonant frequencies. The lower frequency is near the Viaesaela-Brundt frequency, which characterizes the buoyant effect, and the higher frequency is above the ordinary acoustic resonance frequency. This finding shows that the propagation velocity of the acoustic waves is increased due to the pressure gradient effect.

  7. Diffraction of three-colour radiation on an acoustic wave

    SciTech Connect

    Kotov, V M

    2015-07-31

    We study acousto-optic Bragg diffraction of three-colour radiation having wavelengths of 488, 514 and 633 nm on a single acoustic wave propagating in a TeO{sub 2} crystal. A technique is developed that allows one to find diffraction regimes with a proportional change in the intensity of all radiations by varying the acoustic power. According to the technique, radiation with a maximum wavelength has to be in strict Bragg synchronism with the acoustic wave, while other radiations diffract during the synchronism detuning. The results obtained using this technique are experimentally confirmed. (diffraction of light)

  8. Laser-induced surface acoustic waves and their detection via diagnostic systems for detecting radiation damage on steel materials of nuclear devices

    NASA Astrophysics Data System (ADS)

    Kitazawa, Sin-iti; Chiba, Atsuya; Wakai, Eiichi

    2015-06-01

    The development of a non-destructive, non-contact diagnostic system to detect radiation damage is very important for measuring radioactive materials. A system using surface acoustic waves (SAWs) induced and detected by lasers was developed. The propagation velocities of SAWs on stainless steel irradiated by 20 keV He and Ar ions were investigated, and a tendency for the velocity to increase with an increase in ion irradiation was observed. This tendency may be due to surface modification. A non-linear effect on ion irradiation versus normal surface velocity in the vertical direction was confirmed.

  9. Incident Wave Removal for Defect Enhancement in Acoustic Wavefield Imaging

    NASA Astrophysics Data System (ADS)

    Master, Zubin M.; Michaels, Thomas E.; Michaels, Jennifer E.

    2007-03-01

    The method of Acoustic Wavefield Imaging (AWI) offers many advantages over conventional ultrasonic techniques for nondestructive evaluation, and also provides a means of incorporating fixed ultrasonic sensors used for structural health monitoring into subsequent inspections. AWI utilizes these fixed sensors as wave sources and an externally scanned ultrasonic transducer (or laser interferometer) as a receiver to acquire complete waveform data over the surface. When displayed as time-dependent images, these signals show the propagation of acoustic waves through a structure and subsequent interactions of these waves with both defects and structural geometry. Defect areas appear as stationary scattering sources on these images, but such scattered wave energy is often obscured by the stronger incident acoustic wavefield. The objective of the work presented here is to develop multidimensional signal processing algorithms to enhance the appearance of structural defects on wavefield images via removal of the incident wave. Results are presented for analysis of images from aluminum plate and solid laminate composite specimens.

  10. Molecularly Imprinted Polymer Integrated with a Surface Acoustic Wave Technique for Detection of Sulfamethizole.

    PubMed

    Ayankojo, Akinrinade George; Tretjakov, Aleksei; Reut, Jekaterina; Boroznjak, Roman; Öpik, Andres; Rappich, Jörg; Furchner, Andreas; Hinrichs, Karsten; Syritski, Vitali

    2016-01-19

    The synergistic effect of combining molecular imprinting and surface acoustic wave (SAW) technologies for the selective and label-free detection of sulfamethizole as a model antibiotic in aqueous environment was demonstrated. A molecularly imprinted polymer (MIP) for sulfamethizole (SMZ) selective recognition was prepared in the form of a homogeneous thin film on the sensing surfaces of SAW chip by oxidative electropolymerization of m-phenylenediamine (mPD) in the presence of SMZ, acting as a template. Special attention was paid to the rational selection of the functional monomer using computational and spectroscopic approaches. SMZ template incorporation and its subsequent release from the polymer was supported by IR microscopic measurements. Precise control of the thicknesses of the SMZ-MIP and respective nonimprinted reference films (NIP) was achieved by correlating the electrical charge dosage during electrodeposition with spectroscopic ellipsometry measurements in order to ensure accurate interpretation of label-free responses originating from the MIP modified sensor. The fabricated SMZ-MIP films were characterized in terms of their binding affinity and selectivity toward the target by analyzing the binding kinetics recorded using the SAW system. The SMZ-MIPs had SMZ binding capacity approximately more than eight times higher than the respective NIP and were able to discriminate among structurally similar molecules, i.e., sulfanilamide and sulfadimethoxine. The presented approach for the facile integration of a sulfonamide antibiotic-sensing layer with SAW technology allowed observing the real-time binding events of the target molecule at nanomolar concentration levels and could be potentially suitable for cost-effective fabrication of a multianalyte chemosensor for analysis of hazardous pollutants in an aqueous environment.

  11. Single actuator wave-like robot (SAW): design, modeling, and experiments.

    PubMed

    Zarrouk, David; Mann, Moshe; Degani, Nir; Yehuda, Tal; Jarbi, Nissan; Hess, Amotz

    2016-07-01

    In this paper, we present a single actuator wave-like robot, a novel bioinspired robot which can move forward or backward by producing a continuously advancing wave. The robot has a unique minimalistic mechanical design and produces an advancing sine wave, with a large amplitude, using only a single motor but with no internal straight spine. Over horizontal surfaces, the robot does not slide relative to the surface and its direction of locomotion is determined by the direction of rotation of the motor. We developed a kinematic model of the robot that accounts for the two-dimensional mechanics of motion and yields the speed of the links relative to the motor. Based on the optimization of the kinematic model, and accounting for the mechanical constraints, we have designed and built multiple versions of the robot with different sizes and experimentally tested them (see movie). The experimental results were within a few percentages of the expectations. The larger version attained a top speed of 57 cm s(-1) over a horizontal surface and is capable of climbing vertically when placed between two walls. By optimizing the parameters, we succeeded in making the robot travel by 13% faster than its own wave speed.

  12. Surface acoustic wave characterization of optical sol-gel thin layers.

    PubMed

    Fall, Dame; Compoint, François; Duquennoy, Marc; Piombini, Hervé; Ouaftouh, Mohammadi; Jenot, Frédéric; Piwakowski, Bogdan; Belleville, Philippe; Ambard, Chrystel

    2016-05-01

    Controlling the thin film deposition and mechanical properties of materials is a major challenge in several fields of application. We are more particularly interested in the characterization of optical thin layers produced using sol-gel processes to reduce laser-induced damage. The mechanical properties of these coatings must be known to control and maintain optimal performance under various solicitations during their lifetime. It is therefore necessary to have means of characterization adapted to the scale and nature of the deposited materials. In this context, the dispersion of ultrasonic surface waves induced by a micrometric layer was studied on an amorphous substrate (fused silica) coated with a layer of ormosil using a sol-gel process. Our ormosil material is a silica-PDMS mixture with a variable polydimethylsiloxane (PDMS) content. The design and implementation of Surface Acoustic Wave InterDigital Transducers (SAW-IDT) have enabled quasi-monochromatic Rayleigh-type SAW to be generated and the dispersion phenomenon to be studied over a wide frequency range. Young's modulus and Poisson's ratio of coatings were estimated using an inverse method.

  13. SH surface acoustic wave propagation in a cylindrically layered piezomagnetic/piezoelectric structure.

    PubMed

    Du, Jianke; Xian, Kai; Wang, Ji

    2009-01-01

    SH surface acoustic wave (SH-SAW) propagation in a cylindrically layered magneto-electro-elastic structure is investigated analytically, where a piezomagnetic (or piezoelectric) material layer is bonded to a piezoelectric (or piezomagnetic) substrate. By means of transformation, the governing equations of the coupled waves are reduced to Bessel equation and Laplace equation. The boundary conditions imply that the displacements, shear stresses, electric potential, and electric displacements are continuous across the interface between the layer and the substrate together with the traction free at the surface of the layer. The magneto-electrically open and shorted conditions at cylindrical surface are taken to solve the problem. The phase velocity is numerically calculated for different thickness of the layer and wavenumber for piezomagnetic ceramics CoFe(2)O(4) and piezoelectric ceramics BaTiO(3). The effects of magnetic permeability on propagation properties of SH-SAW are discussed in detail. The distributions of displacement, magnetic potential and magneto-electromechanical coupling factor are also figured and discussed.

  14. Ocean-Acoustic Solitary Wave Studies and Predictions

    NASA Astrophysics Data System (ADS)

    Warn-Varnas, A. C.; Chin-Bing, S. A.; King, D. B.; Hallock, Z.; Hawkins, J. A.

    Shallow water internal solitary waves have become a major topic of interest to oceanographers and acousticians. In this paper we review the cross-disciplinary status of joint ocean-acoustic solitary wave studies and predictions. We consider the process of acoustical mode coupling in the presence of solitary waves and the corresponding acoustical intensity loss due to increased coupling with the bottom. A study of the interaction of an acoustical field with a train of solitary waves is undertaken at a range of frequencies. At a resonant frequency the acoustic field can interact with the solitary wave packet which results in mode conversions (acoustic energy is redistributed among the modes, often from lower-order to higher-order modes). Higher signal losses can occur in the higher order modes through increased bottom attenuation and result in an anomalous acoustical intensity loss at the resonant frequency. We present some new results of joint ocean-acoustic research, from a dedicated study in the Strait of Messina, where solitary waves are generated by semidiurnal tidal flow over topographic variations. The University of Hamburg weakly nonhydrostatic two layer model is used for simulating the generation and propagation of solitary waves. In particular, the physical states encountered during an October 1995 cruise in the Strait of Messina (between Italy and Sicily) are simulated. Various parameter space sensitivity studies, about the existing cruise conditions, are performed. The modelled solitary wave trains are compared against conductivity-temperature-depth (CTD) chain measurements in terms of amplitudes, wavelengths, phase speeds and correlations with data. Predicted and observed sound speeds are used in acoustical intensity calculations that are conducted with a parabolic equation (PE) model. The differences in the resultant acoustical intensity fields provide a guide for the tuning of the oceanographic model parameters. The tuned oceanographic model shows

  15. Quantum ion-acoustic wave oscillations in metallic nanowires

    SciTech Connect

    Moradi, Afshin

    2015-05-15

    The low-frequency electrostatic waves in metallic nanowires are studied using the quantum hydrodynamic model, in which the electron and ion components of the system are regarded as a two-species quantum plasma system. The Poisson equation as well as appropriate quantum boundary conditions give the analytical expressions of dispersion relations of the surface and bulk quantum ion-acoustic wave oscillations.

  16. Application of surface acoustic wave devices to radio telemetry

    NASA Technical Reports Server (NTRS)

    Strasilla, U.

    1983-01-01

    Three experimental Surface Acoustic Wave Resonators (SAWR) are developed and evaluated. A desired center frequency is obtained by correct spacing of the Inter-Digital Transducers (IDT). Transmitting and receiving IDT's must be close for adequate coupling and a sufficient number of reflectors are required to create a high quality standing wave. A review of oscillator theory is given and current technology evaluated.

  17. Propagation of acoustic waves in multifractional polydisperse gas suspension

    NASA Astrophysics Data System (ADS)

    Gubaidullin, D. A.; Teregulova, E. A.

    2017-01-01

    The propagation of acoustic waves in multifractional polydisperse gas suspension is studied. A mathematical model is presented, the dispersion equation is obtained, dispersion curves are calculated. The influence of the particle size and the parameters of the dispersed phase for multifractional gas mixture with ice particles, aluminum and sand on dissipation and dispersion of sound waves is analyzed.

  18. INTERFERENCE FRINGES OF SOLAR ACOUSTIC WAVES AROUND SUNSPOTS

    SciTech Connect

    Chou, Dean-Yi; Zhao Hui; Yang, Ming-Hsu; Liang, Zhi-Chao

    2012-10-20

    Solar acoustic waves are scattered by a sunspot due to the interaction between the acoustic waves and the sunspot. The sunspot, excited by the incident wave, generates the scattered wave. The scattered wave is added to the incident wave to form the total wave around the sunspot. The interference fringes between the scattered wave and the incident wave are visible in the intensity of the total wave because the coherent time of the incident wave is of the order of a wave period. The strength of the interference fringes anti-correlates with the width of temporal spectra of the incident wave. The separation between neighboring fringes increases with the incident wavelength and the sunspot size. The strength of the fringes increases with the radial order n of the incident wave from n = 0 to n = 2, and then decreases from n = 2 to n = 5. The interference fringes play a role analogous to holograms in optics. This study suggests the feasibility of using the interference fringes to reconstruct the scattered wavefields of the sunspot, although the quality of the reconstructed wavefields is sensitive to the noise and errors in the interference fringes.

  19. Acoustic Gravity Wave Chemistry Model for the RAYTRACE Code.

    DTIC Science & Technology

    2014-09-26

    AU)-AI56 850 ACOlUSTIC GRAVITY WAVE CHEMISTRY MODEL FOR THE IAYTRACE I/~ CODE(U) MISSION RESEARCH CORP SANTA BARBIARA CA T E OLD Of MAN 84 MC-N-SlS...DNA-TN-S4-127 ONAOOI-BO-C-0022 UNLSSIFIlED F/O 20/14 NL 1-0 2-8 1111 po 312.2 1--I 11111* i •. AD-A 156 850 DNA-TR-84-127 ACOUSTIC GRAVITY WAVE...Hicih Frequency Radio Propaoation Acoustic Gravity Waves 20. ABSTRACT (Continue en reveree mide if tteceeemr and Identify by block number) This

  20. Thermo-acoustic engineering of silicon microresonators via evanescent waves

    SciTech Connect

    Tabrizian, R.; Ayazi, F.

    2015-06-29

    A temperature-compensated silicon micromechanical resonator with a quadratic temperature characteristic is realized by acoustic engineering. Energy-trapped resonance modes are synthesized by acoustic coupling of propagating and evanescent extensional waves in waveguides with rectangular cross section. Highly different temperature sensitivity of propagating and evanescent waves is used to engineer the linear temperature coefficient of frequency. The resulted quadratic temperature characteristic has a well-defined turn-over temperature that can be tailored by relative energy distribution between propagating and evanescent acoustic fields. A 76 MHz prototype is implemented in single crystal silicon. Two high quality factor and closely spaced resonance modes, created from efficient energy trapping of extensional waves, are excited through thin aluminum nitride film. Having different evanescent wave constituents and energy distribution across the device, these modes show different turn over points of 67 °C and 87 °C for their quadratic temperature characteristic.

  1. SAW chemical sensor arrays using new thin-film materials

    SciTech Connect

    Ricco, A.J.; Xu, Chuanjing; Crooks, R.M.; Allred, R.E.

    1994-05-01

    We have used two classes of materials, self-assembled monolayers (SAMs) and plasma-grafted films (PGFs), as new chemically sensitive layers for an array of 97-MHz surface acoustic wave (SAW) delay-line-based devices. Responses of these materials to each of 14 different analytes, representing the classes of saturated alkane, aromatic hydrocarbon, chlorinated hydrocarbon, alcohol, ketone, organophosphonate, and water, have been evaluated using our six-SAW device array. Results reveal a qualitative ``chemical orthogonality`` of the films that is very promising for pattern recognition analysis.

  2. High frequency SAW devices based on third harmonic generation.

    PubMed

    Le Brizoual, L; Elmazria, O; Sarry, F; El Hakiki, M; Talbi, A; Alnot, P

    2006-12-01

    We demonstrate the third harmonic generation in a ZnO/Si layered structure to obtain high frequency SAW devices. This configuration eliminates the need of high lithography resolution and allows easy integration of such devices and electronics on the same wafer. A theoretical study was carried out for the determination of the phase velocity and the electromechanical coupling coefficient (K(2)) dispersion curves of the surface acoustic waves. These results are also in agreement with those measured on a SAW filter designed for the third harmonic generation and the operating frequency is up to 2468 MHz.

  3. X-ray diffraction on the X-cut of a Ca{sub 3}TaGa{sub 3}Si{sub 2}O{sub 14} single crystal modulated by a surface acoustic wave

    SciTech Connect

    Irzhak, D. Roshchupkin, D.

    2014-06-28

    The result of X-ray diffraction study on a single crystal of the calcium-gallogermanate family Ca{sub 3}TaGa{sub 3}Si{sub 2}O{sub 14} (CTGS) modulated by a surface acoustic wave (SAW) is presented. The power flow angle for SAW propagating along the X{sub 2} axis of the X-cut in CTGS was measured. The rocking curves for the CTGS crystal were recorded at different amplitudes of an input high frequency electric signal on interdigital transducer used to excite a SAW. Based on the data obtained, intensity dependence of diffraction satellites on the amplitude of electric signal exciting a SAW was built. Numerical simulation of the crystal rocking curves and dependence of diffraction satellite intensities on the SAW amplitude enabled the selection of a set of material constants at which the most complete coincidence of experimental and calculated results is observed.

  4. Acoustic-Wave-Induced Magnetization Switching of Magnetostrictive Nanomagnets from Single-Domain to Nonvolatile Vortex States

    NASA Astrophysics Data System (ADS)

    Sampath, Vimal; D'Souza, Noel; Bhattacharya, Dhritiman; Atkinson, Gary M.; Bandyopadhyay, Supriyo; Atulasimha, Jayasimha

    2016-09-01

    We report manipulation of the magnetic states of elliptical cobalt magnetostrictive nanomagnets (of nominal dimensions ~ 340 nm x 270 nm x 12 nm) delineated on bulk 128{\\deg} Y-cut lithium niobate with Surface Acoustic Waves (SAWs) launched from interdigitated electrodes. Isolated nanomagnets that are initially magnetized to a single domain state with magnetization pointing along the major axis of the ellipse are driven into a vortex state by surface acoustic waves that modulate the stress anisotropy of these nanomagnets. The nanomagnets remain in the vortex state until they are reset by a strong magnetic field to the initial single domain state, making the vortex state non-volatile. This phenomenon is modeled and explained using a micromagnetic framework and could lead to the development of extremely energy efficient magnetization switching methodologies.

  5. Broadband enhanced transmission of acoustic waves through serrated metal gratings

    NASA Astrophysics Data System (ADS)

    Qi, Dong-Xiang; Fan, Ren-Hao; Deng, Yu-Qiang; Peng, Ru-Wen; Wang, Mu; Jiangnan University Collaboration

    In this talk, we present our studies on broadband properties of acoustic waves through metal gratings. We have demonstrated that serrated metal gratings, which introduce gradient coatings, can give rise to broadband transmission enhancement of acoustic waves. Here, we have experimentally and theoretically studied the acoustic transmission properties of metal gratings with or without serrated boundaries. The average transmission is obviously enhanced for serrated metal gratings within a wide frequency range, while the Fabry-Perot resonance is significantly suppressed. An effective medium hypothesis with varying acoustic impedance is proposed to analyze the mechanism, which was verified through comparison with finite-element simulation. The serrated boundary supplies gradient mass distribution and gradient normal acoustic impedance, which could efficiently reduce the boundary reflection. Further, by increasing the region of the serrated boundary, we present a broadband high-transmission grating for wide range of incident angle. Our results may have potential applications to broadband acoustic imaging, acoustic sensing and new acoustic devices. References: [1] Dong-Xiang Qi, Yu-Qiang Deng, Di-Hu Xu, Ren-Hao Fan, Ru-Wen Peng, Ze-Guo Chen, Ming-Hui Lu, X. R. Huang and Mu Wang, Appl. Phys. Lett. 106, 011906 (2015); [2] Dong-Xiang Qi, Ren-Hao Fan, Ru-Wen Peng, Xian-Rong Huang, Ming-Hui Lu, Xu Ni, Qing Hu, and Mu Wang, Applied Physics Letters 101, 061912 (2012).

  6. Separation of acoustic waves in isentropic flow perturbations

    SciTech Connect

    Henke, Christian

    2015-04-15

    The present contribution investigates the mechanisms of sound generation and propagation in the case of highly-unsteady flows. Based on the linearisation of the isentropic Navier–Stokes equation around a new pathline-averaged base flow, it is demonstrated for the first time that flow perturbations of a non-uniform flow can be split into acoustic and vorticity modes, with the acoustic modes being independent of the vorticity modes. Therefore, we can propose this acoustic perturbation as a general definition of sound. As a consequence of the splitting result, we conclude that the present acoustic perturbation is propagated by the convective wave equation and fulfils Lighthill’s acoustic analogy. Moreover, we can define the deviations of the Navier–Stokes equation from the convective wave equation as “true” sound sources. In contrast to other authors, no assumptions on a slowly varying or irrotational flow are necessary. Using a symmetry argument for the conservation laws, an energy conservation result and a generalisation of the sound intensity are provided. - Highlights: • First splitting of non-uniform flows in acoustic and non-acoustic components. • These result leads to a generalisation of sound which is compatible with Lighthill’s acoustic analogy. • A closed equation for the generation and propagation of sound is given.

  7. Generalized collar waves in acoustic logging while drilling

    NASA Astrophysics Data System (ADS)

    Wang, Xiu-Ming; He, Xiao; Zhang, Xiu-Mei

    2016-12-01

    Tool waves, also named collar waves, propagating along the drill collars in acoustic logging while drilling (ALWD), strongly interfere with the needed P- and S-waves of a penetrated formation, which is a key issue in picking up formation P- and S-wave velocities. Previous studies on physical insulation for the collar waves designed on the collar between the source and the receiver sections did not bring to a satisfactory solution. In this paper, we investigate the propagation features of collar waves in different models. It is confirmed that there exists an indirect collar wave in the synthetic full waves due to the coupling between the drill collar and the borehole, even there is a perfect isolator between the source and the receiver. The direct collar waves propagating all along the tool and the indirect ones produced by echoes from the borehole wall are summarized as the generalized collar waves. Further analyses show that the indirect collar waves could be relatively strong in the full wave data. This is why the collar waves cannot be eliminated with satisfactory effect in many cases by designing the physical isolators carved on the tool. Project supported by the National Natural Science Foundation of China (Grant Nos. 11134011 and 11374322) and the Foresight Research Project, Institute of Acoustics, Chinese Academy of Sciences.

  8. A smart sensor system for trace organic vapor detection using a temperature-controlled array of surface acoustic wave vapor sensors, automated preconcentrator tubes, and pattern recognition

    SciTech Connect

    Grate, J.W.; Rose-Pehrsson, S.L.; Klusty, M.; Wohltjen, H.

    1993-05-01

    A smart sensor system for the detection, of toxic organophosphorus and toxic organosulfur vapors at trace concentrations has been designed, fabricated, and tested against a wide variety of vapor challenges. The key features of the system are: An array of four surface acoustic wave (SAW) vapor sensors, temperature control of the vapor sensors, the use of pattern recognition to analyze the sensor data, and an automated sampling system including thermally-desorbed preconcentrator tubes (PCTs).

  9. Selective Surface Acoustic Wave-Based Organophosphorus Sensor Employing a Host-Guest Self-Assembly Monolayer of β-Cyclodextrin Derivative

    PubMed Central

    Pan, Yong; Mu, Ning; Shao, Shengyu; Yang, Liu; Wang, Wen; Xie, Xiao; He, Shitang

    2015-01-01

    Self-assembly and molecular imprinting technologies are very attractive technologies for the development of artificial recognition systems and provide chemical recognition based on need and not happenstance. In this paper, we employed a β-cyclodextrin derivative surface acoustic wave (SAW) chemical sensor for detecting the chemical warfare agents (CWAs) sarin (O-Isoprophyl methylphosphonofluoridate, GB). Using sarin acid (isoprophyl hydrogen methylphosphonate) as an imprinting template, mono[6-deoxy-6-[(mercaptodecamethylene)thio

  10. Recent advances in particle and droplet manipulation for lab-on-a-chip devices based on surface acoustic waves.

    PubMed

    Wang, Zhuochen; Zhe, Jiang

    2011-04-07

    Manipulation of microscale particles and fluid liquid droplets is an important task for lab-on-a-chip devices for numerous biological researches and applications, such as cell detection and tissue engineering. Particle manipulation techniques based on surface acoustic waves (SAWs) appear effective for lab-on-a-chip devices because they are non-invasive, compatible with soft lithography micromachining, have high energy density, and work for nearly any type of microscale particles. Here we review the most recent research and development of the past two years in SAW based particle and liquid droplet manipulation for lab-on-a-chip devices including particle focusing and separation, particle alignment and patterning, particle directing, and liquid droplet delivery.

  11. Temperature-stabilized silicon-based surface-acoustic-wave gas sensors for the detection of solvent vapors

    NASA Astrophysics Data System (ADS)

    Bender, Stefan; Mokwa, W.

    1998-12-01

    In the current paper a dual-delay-line- and a resonator- device based on CMOS-silicon-technology is presented. As a piezoelectric layer ZnO is used. The layer was deposited at room temperature in a RF magnetron sputter process. Using x- ray diffraction it could be shown that the crystals are mostly oriented with the c-axis (hexagonal structure) perpendicular to the surface which is necessary to conduct surface acoustic waves. Pt electrodes were designed for frequencies between 140 and 600 MHz and were deposited on top using a lift-off-process. A poly-silicon heating resistor was integrated as a sublayer for controlling and changing of the temperature of the SAW-device for studying the influence of temperature on the mass sensitive layer. A Pt thin film resistance served for temperature measurement. The performance of the devices were compared to standard quartz based SAWs.

  12. Characterization of Surface Acoustic Wave Nebulization: Atomization dynamics and resulting droplet size distribution

    NASA Astrophysics Data System (ADS)

    Clark, Alicia; Aliseda, Alberto; Heron, Scott; Huang, Yue; Goodlett, David

    2012-11-01

    High-speed imaging and Phase Doppler Particle Analyzer (PDPA) measurements are used to characterize the size and velocity distributions of micron-sized droplets produced by a surface acoustic wave (SAW) microelectronic nebulizer. The effects of drop composition, electric field amplitude and pulsation frequency, and initial drop volume have been experimentally studied. We observe that the droplets created in pure water are smaller, ~2 μm, and the plume more concentrated near the nebulizer, with small second probability peak for large diameters, ~100 μm. Pure methanol droplets have larger diameters, ~ 5 μm, and lower volume concentration in the nebulizer plume, as corresponds to less efficient atomization process. The influence of fluid viscosity and surface tension will be discussed. Measurements of the velocity distribution show a strong dependency with excitation amplitude and duty factor.

  13. Application of surface-acoustic-wave technology to burst-format spread-spectrum communications

    NASA Astrophysics Data System (ADS)

    Kowatsch, M.

    1984-12-01

    A hybrid direct-sequence/frequency-hopping spread-spectrum communication modem for burst-format transmission of digital data has been developed. A burst consists of a short synchronisation preamble and the data packet. Data modulation is accomplished by assignment of pairs of pseudonoise sequences with low crosscorrelation for message ones and zeros. The spreading code chip pattern is changed from bit to bit in both the preamble and the message portion of a burst. Receiver signal processing is based on the application of surface-acoustic-wave (SAW) elastic convolvers to programmable matched filtering. The performance of the system in an additive white Gaussian noise channel is analysed, measures of performance being the probability of burst loss and the bit error probability in the case of ideal synchronisation. Evaluations for a particular design are presented, and some experimental results obtained with a test system are shown for comparison.

  14. Magneto-acoustic imaging by continuous-wave excitation.

    PubMed

    Shunqi, Zhang; Zhou, Xiaoqing; Tao, Yin; Zhipeng, Liu

    2017-04-01

    The electrical characteristics of tissue yield valuable information for early diagnosis of pathological changes. Magneto-acoustic imaging is a functional approach for imaging of electrical conductivity. This study proposes a continuous-wave magneto-acoustic imaging method. A kHz-range continuous signal with an amplitude range of several volts is used to excite the magneto-acoustic signal and improve the signal-to-noise ratio. The magneto-acoustic signal amplitude and phase are measured to locate the acoustic source via lock-in technology. An optimisation algorithm incorporating nonlinear equations is used to reconstruct the magneto-acoustic source distribution based on the measured amplitude and phase at various frequencies. Validation simulations and experiments were performed in pork samples. The experimental and simulation results agreed well. While the excitation current was reduced to 10 mA, the acoustic signal magnitude increased up to 10(-7) Pa. Experimental reconstruction of the pork tissue showed that the image resolution reached mm levels when the excitation signal was in the kHz range. The signal-to-noise ratio of the detected magneto-acoustic signal was improved by more than 25 dB at 5 kHz when compared to classical 1 MHz pulse excitation. The results reported here will aid further research into magneto-acoustic generation mechanisms and internal tissue conductivity imaging.

  15. Finite difference solutions to shocked acoustic waves

    NASA Technical Reports Server (NTRS)

    Walkington, N. J.; Eversman, W.

    1983-01-01

    The MacCormack, Lambda and split flux finite differencing schemes are used to solve a one dimensional acoustics problem. Two duct configurations were considered, a uniform duct and a converging-diverging nozzle. Asymptotic solutions for these two ducts are compared with the numerical solutions. When the acoustic amplitude and frequency are sufficiently high the acoustic signal shocks. This condition leads to a deterioration of the numerical solutions since viscous terms may be required if the shock is to be resolved. A continuous uniform duct solution is considered to demonstrate how the viscous terms modify the solution. These results are then compared with a shocked solution with and without viscous terms. Generally it is found that the most accurate solutions are those obtained using the minimum possible viscosity coefficients. All of the schemes considered give results accurate enough for acoustic power calculations with no one scheme performing significantly better than the others.

  16. A comparison of Pd and Au electrodes-based LiNbO3 surface acoustic wave devices

    NASA Astrophysics Data System (ADS)

    Liu, Bo; Mohammad, Mohammad Ali; Wang, Dan-Yang; Tian, Xiang-Guang; Tao, Lu-Qi; Yang, Yi; Ren, Tian-Ling

    2016-11-01

    We report the comparison of electrode metals for LiNbO3 surface acoustic wave (SAW) devices. Palladium (Pd) was systematically studied as a SAW electrode metal for the first time, compared with gold (Au). Simulations were first conducted to gain an understanding of the differences of the materials and the metallization ratio. Two sets of identical SAW devices were then fabricated using Au and Pd as electrodes with different electrode widths and same SAW period. The insertion losses, types of resonance mode, the resonance frequencies, peak amplitudes, quality factors and trends with different metallization ratios were systematically compared and analyzed. We found that Pd electrode devices only exhibit the parallel resonance frequency and have higher resonance frequency for both the first-order and third-order harmonics. Au electrode devices tend to have a smooth response and a quality factor two times higher than Pd. Both Pd and Au electrode devices have nearly identical electromechanical coupling coefficients, and the quality factor and third-order harmonics both improve with increasing metallization ratio.

  17. High performance AlScN thin film based surface acoustic wave devices with large electromechanical coupling coefficient

    SciTech Connect

    Wang, Wenbo; He, Xingli; Ye, Zhi E-mail: jl2@bolton.ac.uk; Wang, Xiaozhi; Mayrhofer, Patrick M.; Gillinger, Manuel; Bittner, Achim; Schmid, Ulrich

    2014-09-29

    AlN and AlScN thin films with 27% scandium (Sc) were synthesized by DC magnetron sputtering deposition and used to fabricate surface acoustic wave (SAW) devices. Compared with AlN-based devices, the AlScN SAW devices exhibit much better transmission properties. Scandium doping results in electromechanical coupling coefficient, K{sup 2}, in the range of 2.0% ∼ 2.2% for a wide normalized thickness range, more than a 300% increase compared to that of AlN-based SAW devices, thus demonstrating the potential applications of AlScN in high frequency resonators, sensors, and high efficiency energy harvesting devices. The coupling coefficients of the present AlScN based SAW devices are much higher than that of the theoretical calculation based on some assumptions for AlScN piezoelectric material properties, implying there is a need for in-depth investigations on the material properties of AlScN.

  18. A Dry Membrane Protection Technique to Allow Surface Acoustic Wave Biosensor Measurements of Biological Model Membrane Approaches

    PubMed Central

    Reder-Christ, Katrin; Schmitz, Patrick; Bota, Marian; Gerber, Ursula; Falkenstein-Paul, Hildegard; Fuss, Christian; Enachescu, Marius; Bendas, Gerd

    2013-01-01

    Model membrane approaches have attracted much attention in biomedical sciences to investigate and simulate biological processes. The application of model membrane systems for biosensor measurements is partly restricted by the fact that the integrity of membranes critically depends on the maintenance of an aqueous surrounding, while various biosensors require a preconditioning of dry sensors. This is for example true for the well-established surface acoustic wave (SAW) biosensor SAM®5 blue. Here, a simple drying procedure of sensor-supported model membranes is introduced using the protective disaccharide trehalose. Highly reproducible model membranes were prepared by the Langmuir-Blodgett technique, transferred to SAW sensors and supplemented with a trehalose solution. Membrane rehydration after dry incorporation into the SAW device becomes immediately evident by phase changes. Reconstituted model membranes maintain their full functionality, as indicated by biotin/avidin binding experiments. Atomic force microscopy confirmed the morphological invariability of dried and rehydrated membranes. Approximating to more physiological recognition phenomena, the site-directed immobilization of the integrin VLA-4 into the reconstituted model membrane and subsequent VCAM-1 ligand binding with nanomolar affinity were illustrated. This simple drying procedure is a novel way to combine the model membrane generation by Langmuir-Blodgett technique with SAW biosensor measurements, which extends the applicability of SAM®5 blue in biomedical sciences. PMID:24064603

  19. Inverse least-squares modeling of vapor descriptors using polymer-coated surface acoustic wave sensor array responses.

    PubMed

    Grate, J W; Patrash, S J; Kaganovet, S N; Abraham, M H; Wise, B M; Gallagher, N B

    2001-11-01

    In previous work, it was shown that, in principle, vapor descriptors could be derived from the responses of an array of polymer-coated acoustic wave devices. This new chemometric classification approach was based on polymer/vapor interactions following the well-established linear solvation energy relationships (LSERs) and the surface acoustic wave (SAW) transducers being mass sensitive. Mathematical derivations were included and were supported by simulations. In this work, an experimental data set of polymer-coated SAW vapor sensors is investigated. The data set includes 20 diverse polymers tested against 18 diverse organic vapors. It is shown that interfacial adsorption can influence the response behavior of sensors with nonpolar polymers in response to hydrogen-bonding vapors; however, in general, most sensor responses are related to vapor interactions with the polymers. It is also shown that polymer-coated SAW sensor responses can be empirically modeled with LSERs, deriving an LSER for each individual sensor based on its responses to the 18 vapors. Inverse least-squares methods are used to develop models that correlate and predict vapor descriptors from sensor array responses. Successful correlations can be developed by multiple linear regression (MLR), principal components regression (PCR), and partial least-squares (PLS) regression. MLR yields the best fits to the training data, however cross-validation shows that prediction of vapor descriptors for vapors not in the training set is significantly more successful using PCR or PLS. In addition, the optimal dimension of the PCR and PLS models supports the dimensionality of the LSER formulation and SAW response models.

  20. Modeling Nonlinear Acoustical Blast Waves Outdoors: A Research Summary

    DTIC Science & Technology

    1991-09-01

    Porous Surfaces. 5 David Gottlieb and Eli Turkel, "Dissipative Two-Four Methods for Time Dependent Problems," Mathematical Comnputation, No. 30 (1976...or structure factor, which Attenborough relates to the tortuosity. The local reaction assumption is inhereptly built into this model of the porous...k Waves in the Atmosphere," Journal of the Acoustical Socidy of America, No. 74 (1983). pp 1514-1517. David T. Blackstone., "Nonlinear Acoustics

  1. Broadband Metamaterial for Nonresonant Matching of Acoustic Waves

    DTIC Science & Technology

    2012-03-28

    transmission (EOT)5–8. Lately, it has been extended to acoustic waves, as extraordinary acoustic transmission ( EAT )9–11. Usually these phenomena are achieved... EAT limitations. To this goal, we show a way to manipulate the effective constitutive properties (density reff and sound velocity ceff) of an...obtained. Most EAT phenomena rely on resonance effects that are inherently narrow-band, and for which large transmission is usually hindered by

  2. Passive hybrid sensing tag with flexible substrate saw device

    SciTech Connect

    Skinner, Jack L.; Chu, Eric Y.; Ho, Harvey

    2012-12-25

    The integration of surface acoustic wave (SAW) filters, microfabricated transmission lines, and sensors onto polymer substrates in order to enable a passive wireless sensor platform is described herein. Incident microwave pulses on an integrated antenna are converted to an acoustic wave via a SAW filter and transmitted to an impedance based sensor, which for this work is a photodiode. Changes in the sensor state induce a corresponding change in the impedance of the sensor resulting in a reflectance profile. Data collected at a calibrated receiver is used to infer the state of the sensor. Based on this principal, light levels were passively and wirelessly demonstrated to be sensed at distances of up to about 12 feet.

  3. Increasing the Sensitivity of Surface Acoustic Wave (SAW) Chemical Sensors and other Chemical Sensing Investigations

    DTIC Science & Technology

    2010-03-01

    23 8. Preconcentrator patterns depicted as Poly0 layer of MUMPs ...................... 24 9. PolyMUMPs™ fabrication process......in the Poly0 layer of MUMPs but actual designs submitted included other PolyMUMPs™ layers. Figure 8 Preconcentrator patterns depicted as Poly0

  4. PSAW/MicroSWIS [Microminiature Surface Acoustic Wave (SAW) based Wirelesss Instrumentation System

    NASA Technical Reports Server (NTRS)

    Heermann, Doug; Krug, Eric

    2004-01-01

    This Final Report for the PSAW/MicroSWIS Program is provided in compliance with contract number NAS3-01118. This report documents the overall progress of the program and presents project objectives, work carried out, and results obtained. Program Conceptual Design Package stated the following objectives: To develop a sensor/transceiver network that can support networking operations within spacecraft with sufficient bandwidth so that (1) flight control data, (2) avionics data, (3) payload/experiment data, and (4) prognostic health monitoring sensory information can flow to appropriate locations at frequencies that contain the maximum amount of information content but require minimum interconnect and power: a very high speed, low power, programmable modulation, spread-spectrum radio sensor/transceiver.

  5. Surface acoustic wave devices for harsh environment wireless sensing

    DOE PAGES

    Greve, David W.; Chin, Tao -Lun; Zheng, Peng; ...

    2013-05-24

    In this study, langasite surface acoustic wave devices can be used to implement harsh environment wireless sensing of gas concentration and temperature. This paper reviews prior work on the development of langasite surface acoustic wave devices, followed by a report of recent progress toward the implementation of oxygen gas sensors. Resistive metal oxide films can be used as the oxygen sensing film, although development of an adherent barrier layer will be necessary with the sensing layers studied here to prevent interaction with the langasite substrate. Experimental results are presented for the performance of a langasite surface acoustic wave oxygen sensormore » with tin oxide sensing layer, and these experimental results are correlated with direct measurements of the sensing layer resistivity.« less

  6. Surface acoustic wave devices for harsh environment wireless sensing

    SciTech Connect

    Greve, David W.; Chin, Tao -Lun; Zheng, Peng; Ohodnicki, Paul; Baltrus, John; Oppenheim, Irving J.

    2013-05-24

    In this study, langasite surface acoustic wave devices can be used to implement harsh environment wireless sensing of gas concentration and temperature. This paper reviews prior work on the development of langasite surface acoustic wave devices, followed by a report of recent progress toward the implementation of oxygen gas sensors. Resistive metal oxide films can be used as the oxygen sensing film, although development of an adherent barrier layer will be necessary with the sensing layers studied here to prevent interaction with the langasite substrate. Experimental results are presented for the performance of a langasite surface acoustic wave oxygen sensor with tin oxide sensing layer, and these experimental results are correlated with direct measurements of the sensing layer resistivity.

  7. Broadband metamaterial for nonresonant matching of acoustic waves.

    PubMed

    D'Aguanno, G; Le, K Q; Trimm, R; Alù, A; Mattiucci, N; Mathias, A D; Aközbek, N; Bloemer, M J

    2012-01-01

    Unity transmittance at an interface between bulk media is quite common for polarized electromagnetic waves incident at the Brewster angle, but it is rarely observed for sound waves at any angle of incidence. In the following, we theoretically and experimentally demonstrate an acoustic metamaterial possessing a Brewster-like angle that is completely transparent to sound waves over an ultra-broadband frequency range with >100% bandwidth. The metamaterial, consisting of a hard metal with subwavelength apertures, provides a surface impedance matching mechanism that can be arbitrarily tailored to specific media. The nonresonant nature of the impedance matching effectively decouples the front and back surfaces of the metamaterial allowing one to independently tailor the acoustic impedance at each interface. On the contrary, traditional methods for acoustic impedance matching, for example in medical imaging, rely on resonant tunneling through a thin antireflection layer, which is inherently narrowband and angle specific.

  8. Acoustic waves switch based on meta-fluid phononic crystals

    NASA Astrophysics Data System (ADS)

    Zhu, Xue-Feng

    2012-08-01

    The acoustic waves switch based on meta-fluid phononic crystals (MEFL PCs) is theoretically investigated. The MEFL PCs consist of fluid matrix and fluid-like inclusions with extremely anisotropic-density. The dispersion relations are calculated via the plane wave expansion method, which are in good agreement with the transmitted sound pressure level spectra obtained by the finite element method. The results show that the width of absolute band gap in MEFL PCs depends sensitively upon the orientation of the extremely anisotropic-density inclusions and reaches maximum at the rotating angle of 45°, with the gap position nearly unchanged. Also, the inter-mode conversion inside anisotropic-density inclusions can be ignored due to large acoustic mismatch. The study gives a possibility to realize greater flexibility and stronger effects in tuning the acoustic band gaps, which is very significant in the enhanced control over sound waves and has potential applications in ultrasonic imaging and therapy.

  9. Surface Acoustic Wave Devices for Harsh Environment Wireless Sensing

    PubMed Central

    Greve, David W.; Chin, Tao-Lun; Zheng, Peng; Ohodnicki, Paul; Baltrus, John; Oppenheim, Irving J.

    2013-01-01

    Langasite surface acoustic wave devices can be used to implement harsh-environment wireless sensing of gas concentration and temperature. This paper reviews prior work on the development of langasite surface acoustic wave devices, followed by a report of recent progress toward the implementation of oxygen gas sensors. Resistive metal oxide films can be used as the oxygen sensing film, although development of an adherent barrier layer will be necessary with the sensing layers studied here to prevent interaction with the langasite substrate. Experimental results are presented for the performance of a langasite surface acoustic wave oxygen sensor with tin oxide sensing layer, and these experimental results are correlated with direct measurements of the sensing layer resistivity. PMID:23708273

  10. Single-shot analytical assay based on graphene-oxide-modified surface acoustic wave biosensor for detection of single-nucleotide polymorphisms.

    PubMed

    Liu, Xiang; Wang, Jia-Ying; Mao, Xiao-Bing; Ning, Yong; Zhang, Guo-Jun

    2015-09-15

    The combination of a surface acoustic wave (SAW) biosensor with graphene oxide (GO) provides a promising perspective for detecting DNA mutation. The GO-modified SAW biosensor was prepared by conjugating GO onto the SAW chip surface via electrostatic interaction. Afterward, the probe was immobilized on the GO surface, and detection of DNA mutation was realized by hybridization. The hybridization with a variety of targets would yield different mass and conformational changes on the chip surface, causing the different SAW signals in real time. A total of 137 clinical samples were detected by a single-shot analytical assay based on GO-modified SAW biosensor and direct sequencing in parallel. The diagnostic performance (both sensitivity and specificity) of the assay was evaluated with the direct sequencing as a reference testing method. The phase-shift value of three genotypes in 137 clinical samples was significantly different (p < 0.001). Furthermore, testing of diagnostic performance yielded diagnostic sensitivity and specificity of 100% and 88.6% for identifying CT and CC genotype, 98.0% and 96.2% for identifying CT and TT genotype, respectively. The single-shot analytical assay based on the GO-modified SAW biosensor could be exploited as a potential useful tool to identify CYP2D6*10 polymorphisms in clinical practice of personalized medicine.

  11. Evaluation and criterion determination of the low-k thin film adhesion by the surface acoustic waves with cohesive zone model

    NASA Astrophysics Data System (ADS)

    Xiao, Xia; Qi, Haiyang; Sui, Xiaole; Kikkawa, Takamaro

    2017-03-01

    The cohesive zone model (CZM) is introduced in the surface acoustic wave (SAW) technique to characterize the interfacial adhesion property of the low-k thin film deposited on the Silicon substrate. The ratio of the two parameters in the CZM, the maximum normal traction and normal interface characteristic length, is derived to evaluate the interfacial adhesion properties quantitatively. In this study, the adhesion criterion to judge the adhesion property is newly proposed by the CZM-SAW technique. The criterion determination processes of two kinds of film, dense and porous Black Diamond with different film thicknesses, are presented in this paper. The interfacial adhesion properties of the dense and porous Black Diamond films with different thicknesses are evaluated by the CZM-SAW technique quantitatively and nondestructively. The quantitative adhesion properties are obtained by fitting the experimental dispersion curves with maximum frequency up to 220 MHz with the theoretical ones. Results of the nondestructive CZM-SAW technique and the destructive nanoscratch exhibit the same trend in adhesion properties, which means that the CZM-SAW technique is a promising method for determining the interfacial adhesion. Meanwhile, the adhesion properties of the detected samples are judged by the determined criterion. The test results show that different test film materials with different film thicknesses ranging from 300 nm to 1000 nm are in different adhered conditions. This paper exhibits the advantage of the CZM-SAW technique which can be a universal method to characterize the film adhesion.

  12. Particle-Wave Micro-Dynamics in Nonlinear Self-Excited Dust Acoustic Waves

    SciTech Connect

    Tsai, C.-Y.; Teng, L.-W.; Liao, C.-T.; I Lin

    2008-09-07

    The large amplitude dust acoustic wave can be self-excited in a low-pressure dusty plasma. In the wave, the nonlinear wave-particle interaction determines particle motion, which in turn determines the waveform and wave propagation. In this work, the above behaviors are investigated by directly tracking particle motion through video-microscopy. A Lagrangian picture for the wave dynamics is constructed. The wave particle interaction associated with the transition from ordered to disordered particle oscillation, the wave crest trapping and wave heating are demonstrated and discussed.

  13. Lagrangian-Eulerian micromotion and wave heating in nonlinear self-excited dust-acoustic waves.

    PubMed

    Liao, Chen-Ting; Teng, Lee-Wen; Tsai, Chen-Yu; Io, Chong-Wai; I, Lin

    2008-05-09

    We investigate particle-wave microdynamics in the large amplitude self-excited dust acoustic wave at the discrete level through direct visualization. The wave field induces dust oscillations which in turn sustain wave propagation. In the regular wave with increasing wave amplitude, dust-wave interaction with uncertain temporary crest trapping and dust-dust interaction lead to the transition from cyclic to disordered dust motion associated with the liquid to the gas transition, and anisotropic non-Gaussian heating. In the irregular wave, particle trough-trapping is also observed, and the heating is nearly Gaussian and less anisotropic.

  14. A metasurface carpet cloak for electromagnetic, acoustic and water waves.

    PubMed

    Yang, Yihao; Wang, Huaping; Yu, Faxin; Xu, Zhiwei; Chen, Hongsheng

    2016-01-29

    We propose a single low-profile skin metasurface carpet cloak to hide objects with arbitrary shape and size under three different waves, i.e., electromagnetic (EM) waves, acoustic waves and water waves. We first present a metasurface which can control the local reflection phase of these three waves. By taking advantage of this metasurface, we then design a metasurface carpet cloak which provides an additional phase to compensate the phase distortion introduced by a bump, thus restoring the reflection waves as if the incident waves impinge onto a flat mirror. The finite element simulation results demonstrate that an object can be hidden under these three kinds of waves with a single metasurface cloak.

  15. Calibration of the QCM/SAW Cascade Impactor for Measurement of Ozone

    NASA Technical Reports Server (NTRS)

    Williams, Cassandra K.; Peterson, C. B.; Morris, V. R.

    1997-01-01

    The Quartz Crystal Microbalance Surface Acoustic Wave (QCM/SAW) cascade impactor is an instrument designed to collect size-fractionated distributions of aerosols on a series of quartz crystals and employ SAW devices coated with chemical sensors for gas detection. We are calibrating the cascade impactor in our laboratory for future deployment for in-situ experiments to measure ozone. Experiments have been performed to characterize the QCM and SAW mass loading, saturation limits, mass frequency relationships, and sensitivity. The characteristics of mass loading, saturation limits, mass-frequency relationships, sensitivity, and the loss of ozone on different materials have been quantified.

  16. Amplification of acoustic evanescent waves using metamaterial slabs.

    PubMed

    Park, Choon Mahn; Park, Jong Jin; Lee, Seung Hwan; Seo, Yong Mun; Kim, Chul Koo; Lee, Sam H

    2011-11-04

    We amplified acoustic evanescent waves using metamaterial slabs with a negative effective density. For the amplifying effect of the slab to overcome the dissipation, it is necessary that the imaginary part of the effective density is much smaller than the real part, a condition not satisfied so far. We report the construction of membrane-based two-dimensional negative-density metamaterials which exhibited remarkably small dissipation. Using a slab of this metamaterial we realized a 17-fold net amplitude gain at a remote distance from the evanescent wave source. Potential applications include acoustic superlensing.

  17. Anisotropic diffraction of bulk acoustic wave beams in lithium niobate.

    PubMed

    Naumenko, Natalya F; Chizhikov, Sergey I; Molchanov, Vladimir Ya; Yushkov, Konstantin B

    2015-12-01

    The formalism of planar diffraction tensor was applied to the analysis of anisotropy of bulk acoustic wave diffraction and to build a full map of anisotropic diffractional coefficients for three bulk acoustic wave modes propagating in lithium niobate. For arbitrary propagation direction the diffractional coefficients derived allow estimation of ultrasonic beam divergence in far-field. Analysis of obtained data revealed that the maxima of acousto-optic figure of merit for anisotropic diffraction in the YZ plane correspond to moderate diffractional spreading of the beams exceeding isotropic diffraction 2-3 times.

  18. Surface acoustic wave/silicon monolithic sensor/processor

    NASA Technical Reports Server (NTRS)

    Kowel, S. T.; Kornreich, P. G.; Nouhi, A.; Kilmer, R.; Fathimulla, M. A.; Mehter, E.

    1983-01-01

    A new technique for sputter deposition of piezoelectric zinc oxide (ZnO) is described. An argon-ion milling system was converted to sputter zinc oxide films in an oxygen atmosphere using a pure zinc oxide target. Piezoelectric films were grown on silicon dioxide and silicon dioxide overlayed with gold. The sputtered films were evaluated using surface acoustic wave measurements, X-ray diffraction, scanning electron microscopy, Auger electron spectroscopy, and resistivity measurements. The effect of the sputtering conditions on the film quality and the result of post-deposition annealing are discussed. The application of these films to the generation of surface acoustic waves is also discussed.

  19. Properties of Materials Using Acoustic Waves.

    DTIC Science & Technology

    1984-10-01

    CLASSiFICATIOO OF THIS PAGIR elM. DMe Eatae" to nonlinear acoustics which should permit us to cast problems with geometric and other complexities into a...on the kinetics of chemical reactions . 5. New theoretical approaches in nonlinear acoustics (R.M. McGowan and Professor B.-T. Chu) We are working to...of water and methanol was compared with the theoretical predictions given by Marston’s theory and the simplified model (Hsu 1983). This set of data

  20. Detection of third-hand smoke on clothing fibers with a surface acoustic wave gas sensor

    PubMed Central

    Cheng, Chi-Yung; Huang, Shih-Shen; Yang, Chia-Min; Tang, Kea-Tiong

    2016-01-01

    Third-hand smoke (THS) is a new cigarette-related issue defined as the residual contamination from cigarette smoke after a cigarette is extinguished. To detect THS on three commonly used clothing fibers—wool, cotton, and polyester, we applied two methods to measure the adsorption of THS: one was the gain of mass with an analytical balance after exposure to cigarette smoke; and the other was to detect the THS chemical compounds such as nicotine and 3-ethenylpyridine with a surface acoustic wave (SAW) sensor composed of coated oxidized hollow mesoporous carbon nanospheres. In the mass measurement, the gain of mass decreased in the order wool, cotton, and polyester; the latter gain was about one tenth that of wool. In the SAW detection, the frequency shift decreased in the same order—wool, cotton, and polyester. The residence period of THS on natural fiber (wool and cotton) is greater than on synthetic polyester fiber. These two tests provide quantitative results of THS on varied clothing fibers, to assess their risk after exposure to cigarette smoke. PMID:26909119

  1. Effect of spherical magnetic particles on liquid crystals behavior studied by surface acoustic waves

    NASA Astrophysics Data System (ADS)

    Bury, Peter; Kúdelčík, Jozef; Hardoň, Štefan; Veveričik, Marek; Kopčanský, Peter; Timko, Milan; Závišová, Vlasta

    2017-02-01

    The effect of spherical magnetic particles (Fe3O4) on liquid crystals (6CHBT) behavior and structural changes in electric and weak magnetic fields was studied by means of the attenuation of surface acoustic wave (SAW) of frequency 30 MHz propagating along ferronematic liquid crystals. Three low volume concentrations (Φ = 1 ×10-5 , 1 ×10-4 and 1 ×10-3) of spherical magnetic particles were added to liquid crystal during its isotropic phase. In contrast to undoped 6CHTB the distinctive SAW attenuation responses induced by both electric and magnetic fields in studied ferronematic liquid crystals below Fréedericksz transition have been observed suggesting both structural changes and the orientational coupling between magnetic moments of magnetic particles and the director of the liquid crystal. The geometrical re-ranking of magnetic particles was registered only for some orientations of magnetic field. Observed results confirmed the significant influence of the presence of magnetic particles on the structural properties and following behavior of 6CHTB.

  2. Design of a radio-linked implantable cochlear prosthesis using surface acoustic wave devices.

    PubMed

    Jeutter, D C; Josse, F

    1993-01-01

    Cochlear prosthesis systems for postlingually deaf individuals (those who have become deaf due to disease or injury after having developed mature speech capability) are considered. These systems require the surgical implantation of an array of electrodes within the cochlea and are driven by processed sound signals from outside the body. A system that uses an analog signal approach for transcutaneous transfer of six processed speech data channels using frequency multiplexing is described. The system utilizes a filterbank of six narrowband surface acoustic wave (SAW) filters in the range 72-78 MHz with a 1.2-MHz channel spacing to multiplex the six carrier signals, frequency modulated, by the processed speech signals, onto a composite signal. The same SAW filters are used in the receiver filterbank for signal separation, but are housed in a miniaturized package. The system includes a portable transmitter and a receiver package which is to be implanted in the patient. The implanted circuits are supplied exclusively from power transferred from outside the body via a separate 10-MHz transcutaneous link.

  3. Surface acoustic wave ammonia sensor based on ZnO/SiO2 composite film.

    PubMed

    Wang, Shuang-Yue; Ma, Jin-Yi; Li, Zhi-Jie; Su, H Q; Alkurd, N R; Zhou, Wei-Lie; Wang, Lu; Du, Bo; Tang, Yong-Liang; Ao, Dong-Yi; Zhang, Shou-Chao; Yu, Q K; Zu, Xiao-Tao

    2015-03-21

    A surface acoustic wave (SAW) resonator with ZnO/SiO2 (ZS) composite film was used as an ammonia sensor in this study. ZS composite films were deposited on the surface of SAW devices using the sol-gel method, and were characterized using SEM, AFM, and XRD. The performance of the sensors under ammonia gas was optimized by adjusting the molar ratio of ZnO:SiO2 to 1:1, 1:2 and 1:3, and the sensor with the ratio of ZnO to SiO2 equaling to 1:2 was found to have the best performance. The response of sensor was 1.132 kHz under 10 ppm NH3, which was much higher than that of the sensor based on a pristine ZnO film. Moreover, the sensor has good selectivity, reversibility and stability at room temperature. These can be attributed to the enhanced absorption of ammonia and unique surface reaction on composite films due to the existence of silica.

  4. Acoustic measurements of air entrainment by breaking waves

    NASA Astrophysics Data System (ADS)

    Terrill, Eric James

    1998-11-01

    Wave breaking at the surface of the ocean plays an important role in air-sea interaction processes. Bubbles entrained by breaking waves not only enhance the transfer of atmospheric gases to the ocean, but also modify the phase speed and attenuation of acoustic waves propagating through the bubbly medium. The development of acoustic instruments to measure bubbles and the results obtained from a number of field and laboratory experiments are presented. The first part of this dissertation addresses sound speed measurements made in the North Atlantic as part of the Acoustic Surface Reverberation Experiment (ASREX). An autonomous buoy system that directly measures the sound speed in the surface wave layer was developed. Data obtained with the instrument spanned several storm cycles with wind speeds and significant wave heights reaching 20 m/s and 8 m, respectively. The use of Wood's relation (1946) allows the calculation of the void fraction of air based on the low-frequency sound speed measurements. The highly variable near-surface sound speed/void fraction field is analyzed with respect to wind and surface wave- breaking parameters. The second part of this dissertation presents the development of a broadband acoustic technique which simultaneously measures the phase speed and attenuation at acoustic frequencies ranging from 4-100 kHz. The acoustic data is inverted for the size distribution of bubbles using algorithms that are based upon the physics of sound propagation through a bubbly mixture. This acoustic technique was evaluated in the large wave channel at the Hydraulics Laboratory, Scripps Institution of Oceanography, using mechanically generated breaking waves in seawater. Field measurements of bubble concentrations that result from wave breaking were made in both shallow water off Scripps Pier, California and in deep water near Point Conception, California using the broadband technique. Significant variability is observed in the bubble field, characterized by

  5. Efficient counter-propagating wave acoustic micro-particle manipulation

    NASA Astrophysics Data System (ADS)

    Grinenko, A.; Ong, C. K.; Courtney, C. R. P.; Wilcox, P. D.; Drinkwater, B. W.

    2012-12-01

    A simple acoustic system consisting of a pair of parallel singe layered piezoelectric transducers submerged in a fluid used to form standing waves by a superposition of two counter-propagating waves is reported. The nodal positions of the standing wave are controlled by applying a variable phase difference to the transducers. This system was used to manipulate polystyrene micro-beads trapped at the nodal positions of the standing wave. The demonstrated good manipulation capability of the system is based on a lowering of the reflection coefficient in a narrow frequency band near the through-thickness resonance of the transducer plates.

  6. Linear coupling of acoustic and cyclotron waves in plasma flows

    SciTech Connect

    Rogava, Andria; Gogoberidze, Grigol

    2005-05-15

    It is found that in magnetized electrostatic plasma flows the velocity shear couples ion-acoustic waves with ion-cyclotron waves and leads, under favorable conditions, to their efficient reciprocal transformations. It is shown that in a two-dimensional setup this coupling has a remarkable feature: it is governed by equations that are mathematically equal to the ones describing coupling of sound waves with internal gravity waves [Rogava and Mahajan, Phys. Rev. E 55, 1185 (1997)] in neutral fluids. For flows with low shearing rates a fully analytic, quantitative description of the coupling efficiency, based on a noteworthy quantum-mechanical analogy, is given and transformation coefficients are calculated.

  7. Measuring acoustic nonlinearity parameter using collinear wave mixing

    NASA Astrophysics Data System (ADS)

    Liu, Minghe; Tang, Guangxin; Jacobs, Laurence J.; Qu, Jianmin

    2012-07-01

    This study introduces a new acoustic nonlinearity parameter βT. It is shown that βT is associated with the interaction between a longitudinal wave and a shear wave in isotropic elastic solids with quadratic nonlinearity. Experimental measurements are conducted to demonstrate that the collinear wave mixing technique is capable of measuring βT nondestructively. Further, it is shown that βT is well-correlated with the plastic deformation in Al-6061 alloys. These results indicate that collinear wave mixing is a promising method for nondestructive assessment of plastic deformation, and possibly, fatigue damage in metallic materials.

  8. Growth and Characterization of Polyimide-Supported AlN Films for Flexible Surface Acoustic Wave Devices

    NASA Astrophysics Data System (ADS)

    Li, Qi; Liu, Hongyan; Li, Gen; Zeng, Fei; Pan, Feng; Luo, Jingting; Qian, Lirong

    2016-06-01

    Highly c-axis oriented aluminum nitride (AlN) films, which can be used in flexible surface acoustic wave (SAW) devices, were successfully deposited on polyimide (PI) substrates by direct current reactive magnetron sputtering without heating. The sputtering power, film thickness, and deposition pressure were optimized. The characterization studies show that at the optimized conditions, the deposited AlN films are composed of columnar grains, which penetrate through the entire film thickness (~2 μm) and exhibit an excellent (0002) texture with a full width at half maximum value of the rocking curve equal to 2.96°. The film surface is smooth with a root mean square value of roughness of 3.79 nm. SAW prototype devices with a center frequency of about 520 MHz and a phase velocity of Rayleigh wave of about 4160 m/s were successfully fabricated using the AlN/PI composite structure. The obtained results demonstrate that the highly c-axis oriented AlN films with a smooth surface and low stress can be produced on relatively rough, flexible substrates, and this composite structure can be possibly used in flexible SAW devices.

  9. Chromospheric extents predicted by time-dependent acoustic wave models

    NASA Astrophysics Data System (ADS)

    Cuntz, Manfred

    1990-01-01

    Theoretical models for chromospheric structures of late-type giant stars are computed, including the time-dependent propagation of acoustic waves. Models with short-period monochromatic shock waves as well as a spectrum of acoustic waves are discussed, and the method is applied to the stars Arcturus, Aldebaran, and Betelgeuse. Chromospheric extent, defined as the monotonic decrease with height of the time-averaged electron densities, are found to be 1.12, 1.13, and 1.22 stellar radii for the three stars, respectively; this corresponds to a time-averaged electron density of 10 to the 7th/cu cm. Predictions of the extended chromospheric obtained using a simple scaling law agree well with those obtained by the time-dependent wave models; thus, the chromospheres of all stars for which the scaling law is valid consist of the same number of pressure scale heights.

  10. Chromospheric extents predicted by time-dependent acoustic wave models

    SciTech Connect

    Cuntz, M. Heidelberg Universitaet )

    1990-01-01

    Theoretical models for chromospheric structures of late-type giant stars are computed, including the time-dependent propagation of acoustic waves. Models with short-period monochromatic shock waves as well as a spectrum of acoustic waves are discussed, and the method is applied to the stars Arcturus, Aldebaran, and Betelgeuse. Chromospheric extent, defined as the monotonic decrease with height of the time-averaged electron densities, are found to be 1.12, 1.13, and 1.22 stellar radii for the three stars, respectively; this corresponds to a time-averaged electron density of 10 to the 7th/cu cm. Predictions of the extended chromospheric obtained using a simple scaling law agree well with those obtained by the time-dependent wave models; thus, the chromospheres of all stars for which the scaling law is valid consist of the same number of pressure scale heights. 74 refs.

  11. Waveform inversion of acoustic waves for explosion yield estimation

    DOE PAGES

    Kim, K.; Rodgers, A. J.

    2016-07-08

    We present a new waveform inversion technique to estimate the energy of near-surface explosions using atmospheric acoustic waves. Conventional methods often employ air blast models based on a homogeneous atmosphere, where the acoustic wave propagation effects (e.g., refraction and diffraction) are not taken into account, and therefore, their accuracy decreases with increasing source-receiver distance. In this study, three-dimensional acoustic simulations are performed with a finite difference method in realistic atmospheres and topography, and the modeled acoustic Green's functions are incorporated into the waveform inversion for the acoustic source time functions. The strength of the acoustic source is related to explosionmore » yield based on a standard air blast model. The technique was applied to local explosions (<10 km) and provided reasonable yield estimates (<~30% error) in the presence of realistic topography and atmospheric structure. In conclusion, the presented method can be extended to explosions recorded at far distance provided proper meteorological specifications.« less

  12. Real-time SAW measurements of NVR in cleanroom and in microenvironment

    SciTech Connect

    Liang, A.Y.; McIntyre, D.C.; Lujan, R.D.; Thornberg, S.M.; Bender, S.F.A.

    1994-05-01

    Using a real-time, Surface Acoustic Wave (SAW) sensing instrument supplied by Femtometrics, we have measured organic contamination, or nonvolatile residues (NVR), in both a cleanroom and a microenvironment. To demonstrate the {open_quotes}real-time{close_quotes} NVR detectability and sensitivity of the SAW instrument, controlled contamination experiments with photoresist material were also conducted. In addition, two cleaning methods for removing contamination from used sensors have been evaluated. One technique uses the on-board temperature varying capability of the SAW instrument, while the other technique utilizes a uv-ozone cleaner for the sensor cleaning. Preliminary results from SAW measurements in the cleanroom and in a microenvironment and tests to evaluate sensor cleaning techniques are presented in this report. A concluding summary with an assessment of the current SAW instrument and potential future applications for this technology is also presented.

  13. Acoustic and elastic waves in metamaterials for underwater applications

    NASA Astrophysics Data System (ADS)

    Titovich, Alexey S.

    Elastic effects in acoustic metamaterials are investigated. Water-based periodic arrays of elastic scatterers, sonic crystals, suffer from low transmission due to the impedance and index mismatch of typical engineering materials with water. A new type of acoustic metamaterial element is proposed that can be tuned to match the acoustic properties of water in the quasi-static regime. The element comprises a hollow elastic cylindrical shell fitted with an optimized internal substructure consisting of a central mass supported by an axisymmetric distribution of elastic stiffeners, which dictate the shell's effective bulk modulus and density. The derived closed form scattering solution for this system shows that the subsonic flexural waves excited in the shell by the attachment of stiffeners are suppressed by including a sufficiently large number of such stiffeners. As an example of refraction-based wave steering, a cylindrical-to-plane wave lens is designed by varying the bulk modulus in the array according to the conformal mapping of a unit circle to a square. Elastic shells provide rich scattering properties, mainly due to their ability to support highly dispersive flexural waves. Analysis of flexural-borne waves on a pair of shells yields an analytical expression for the width of a flexural resonance, which is then used with the theory of multiple scattering to accurately predict the splitting of the resonance frequency. This analysis leads to the discovery of the acoustic Poisson-like effect in a periodic wave medium. This effect redirects an incident acoustic wave by 90° in an otherwise acoustically transparent sonic crystal. An unresponsive "deaf" antisymmetric mode locked to band gap boundaries is unlocked by matching Bragg scattering with a quadrupole flexural resonance of the shell. The dynamic effect causes normal unidirectional wave motion to strongly couple to perpendicular motion, analogous to the quasi-static Poisson effect in solids. The Poisson

  14. X-ray diffraction and surface acoustic wave analysis of BST/Pt/TiO{sub 2}/SiO{sub 2}/Si thin films

    SciTech Connect

    Mseddi, Souhir; Hedi Ben Ghozlen, Mohamed; Njeh, Anouar; Schneider, Dieter; Fuess, Hartmut

    2011-11-15

    High dielectric constant and electrostriction property of (Ba, Sr)Ti0{sub 3} (BST) thin films result in an increasing interest for dielectric devices and microwave acoustic resonator. Barium strontium titanate (Ba{sub 0.645}Sr{sub 0.355}TiO{sub 3}) films of about 300 nm thickness are grown on Pt(111)/TiO{sub 2}/SiO{sub 2}/Si(001) substrates by rf magnetron sputtering deposition techniques. X-ray diffraction is applied for the microstructural characterization. The BST films exhibit a cubic perovskite structure with a dense and smooth surface. A laser acoustic waves (LA-waves) technique is used to generate surface acoustic waves (SAW) propagating in the BST films. Young's modulus E and the Poisson ratio {nu} of TiO{sub 2,} Pt and BST films in different propagation directions are derived from the measured dispersion curves. Estimation of BST elastics constants are served in SAW studies. Impact of stratification process on SAW, propagating along [100] and [110] directions of silicon substrate, has been interpreted on the basis of ordinary differential equation (ODE) and stiffness matrix method (SMM). A good agreement is observed between experimental and calculated dispersion curves. The performed calculations are strongly related to the implemented crystallographic data of each layer. Dispersion curves are found to be sensitive to the SAW propagation direction and the stratification process for the explored frequency ranges 50-250 MHz, even though it corresponds to a wave length clearly higher than the whole films thickness.

  15. Asymptotic permanent profile of the ion acoustic wave driven by the Langmuir wave

    NASA Astrophysics Data System (ADS)

    Kaup, D. J.; Latifi, A.; Leon, J.

    1992-08-01

    We study the evolution of Langmuir waves coupled to the ion acoustic wave by means of the ponderomotive force in the Karpman limit (caviton equation). Using the spectral transform with singular dispersion relation, it is shown that the background noise (fluctuations in the ion density) is amplified and its time asymptotic behavior will be a static solution which is totally reflective for the Langmuir wave. Moreover, if the initial ion density contains a local depression, the asymptotic profile will contain a number of permanent localized density depressions (cavitons), static in the rest frame of the acoustic wave and entrained in its wake.

  16. Ion-Acoustic Waves in Self-Gravitaing Dusty Plasma

    SciTech Connect

    Kumar, Nagendra; Kumar, Vinod; Kumar, Anil

    2008-09-07

    The propagation and damping of low frequency ion-acoustic waves in steady state, unmagnetised, self-gravitating dusty plasma are studied taking into account two important damping mechanisms creation damping and Tromso damping. It is found that imaginary part of wave number is independent of frequency in case of creation damping. But when we consider the case of creation and Tromso damping together, an additional contribution to damping appears with the increase in frequency attributed to Tromso effect.

  17. Estimation of Sea Surface Wave Spectra Using Acoustic Tomography.

    DTIC Science & Technology

    1987-09-01

    develops a new technique for estimating quasi- homogeneous and quasi-stationary sea surface wave frequency-direction spectra using acoustic tomog...problems for the homogeneous and quasi- homogeneous frequency-direction spectrum are introduced. The theory is ap- plied tosynthetic data which simulate...thesis introduces a technique that estimates the quasi-stationary and quasi- homogeneous sea surface wave frequency-direction spectrum from the spectra of

  18. S-Band Shallow Bulk Acoustic Wave (SBAW) microwave source

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Techniques necessary to fabricate a high performance S-band microwave single source using state-of-the-art shallow bulk acoustic wave (SBAW) were explored. The bulk wave structures of the AlN/Al 2O3 were investigated for both the R plane and basal plane of sapphire. A 1.072 GHz SBAW delay line and oscillators were developed. A method of selecting and setting oscillator output frequency by selecting substrate orientation angle was also established.

  19. Dust acoustic shock waves in two temperatures charged dusty grains

    SciTech Connect

    El-Shewy, E. K.; Abdelwahed, H. G.; Elmessary, M. A.

    2011-11-15

    The reductive perturbation method has been used to derive the Korteweg-de Vries-Burger equation and modified Korteweg-de Vries-Burger for dust acoustic shock waves in a homogeneous unmagnetized plasma having electrons, singly charged ions, hot and cold dust species with Boltzmann distributions for electrons and ions in the presence of the cold (hot) dust viscosity coefficients. The behavior of the shock waves in the dusty plasma has been investigated.

  20. Simulation of SAW Humidity Sensors Based on (112¯0)ZnO/R-Sapphire Structures

    PubMed Central

    Lan, Xiao-Dong; Zhang, Shu-Yi; Fan, Li; Wang, Yan

    2016-01-01

    The characteristics of two types of surface acoustic waves SAWs (Rayleigh waves and Love waves) propagating in bilayered structures of (112¯0)ZnO/R-sapphire are simulated by a finite element method (FEM) model, in which both SAWs have crossed propagation directions. Furthermore, based on the bilayered structures, the frequency responses of Rayleigh wave and Love wave humidity sensors are also simulated. Meanwhile, the frequency shifts, insertion loss changes and then the sensitivities of both humidity sensors induced by the adsorbed water layer perturbations, including the mechanical and electrical factors, are calculated numerically. Generally, the characteristics and performances of both sensors are strongly dependent on the thickness of the ZnO films. By appropriate selecting the ratio of the film thickness to SAW wavelength for each kind of the sensors, the performances of both sensors can be optimized. PMID:27827856

  1. The detection properties of ammonia SAW gas sensors based on L-glutamic acid hydrochloride.

    PubMed

    Shen, Chi-Yen; Huang, Chun-Pu; Huang, Wang-Tsung

    2005-10-01

    This study has investigated an improved surface acoustic wave (SAW) ammonia gas sensor based on L-glutamic acid hydrochloride. It presents an excellent reversibility, sensitivity, and repeatability to ammonia. The frequency shift versus ammonia concentration above 40 degrees C was a monotonic function, and the limit of detection of the sensor at 50 degrees C was 80 ppb.

  2. Interaction of acoustic waves generated by coupled plate

    NASA Technical Reports Server (NTRS)

    Cuschieri, J. M.

    1990-01-01

    When two substructures are coupled, the acoustic field generated by the motion of each of the substructures will interact with the motion of the other substructure. This would be the case of a structure enclosing an acoustic cavity. A technique to model the interaction of the generated sound fields from the two components of a coupled structure, and the influence of this interaction on the vibration of the structural components is presented. Using a mobility power flow approach, each element of the substructure is treated independently both when developing the structural response and when determining the acoustic field generated by this component. The presence of the other substructural components is introduced by assuming these components to be rigid baffles. The excitation of one of the substructures is assumed to be by an incident acoustic wave which is dependent of the motion of the substructure. The sound field generated by the motion of the substructure is included in the solution of the response.

  3. Standing surface acoustic wave (SSAW)-based cell washing

    PubMed Central

    Li, Sixing; Ding, Xiaoyun; Mao, Zhangming; Chen, Yuchao; Nama, Nitesh; Guo, Feng; Li, Peng; Wang, Lin; Cameron, Craig E.; Huang, Tony Jun

    2014-01-01

    Cell/bead washing is an indispensable sample preparation procedure used in various cell studies and analytical processes. In this article, we report a standing surface acoustic wave (SSAW)-based microfluidic device for cell and bead washing in a continuous flow. In our approach, the acoustic radiation force generated in a SSAW field is utilized to actively extract cells or beads from their original medium. A unique configuration of tilted-angle standing surface acoustic wave (taSSAW) is employed in our device, enabling us to wash beads with >98% recovery rate and >97% washing efficiency. We also demonstrate the functionality of our device by preparing high-purity (>97%) white blood cells from lysed blood samples through cell washing. Our SSAW-based cell/bead washing device has the advantages of label-free manipulation, simplicity, high biocompatibility, high recovery rate, and high washing efficiency. It can be useful for many lab-on-a-chip applications. PMID:25372273

  4. Gasoline identifier based on SH0 plate acoustic waves.

    PubMed

    Kuznetsova, Iren E; Zaitsev, Boris D; Seleznev, Eugenii P; Verona, Enrico

    2016-08-01

    The present paper is devoted to the development of gasoline identifier based on zero order shear-horizontal (SH0) acoustic wave propagating in piezoelectric plate. It has been found that the permittivity of gasoline is increased when its octane number rises. The development of such identifier is experimentally demonstrated to be possible.

  5. Corrigendum and addendum. Modeling weakly nonlinear acoustic wave propagation

    DOE PAGES

    Christov, Ivan; Christov, C. I.; Jordan, P. M.

    2014-12-18

    This article presents errors, corrections, and additions to the research outlined in the following citation: Christov, I., Christov, C. I., & Jordan, P. M. (2007). Modeling weakly nonlinear acoustic wave propagation. The Quarterly Journal of Mechanics and Applied Mathematics, 60(4), 473-495.

  6. Acoustic wave propagation in high-pressure system.

    PubMed

    Foldyna, Josef; Sitek, Libor; Habán, Vladimír

    2006-12-22

    Recently, substantial attention is paid to the development of methods of generation of pulsations in high-pressure systems to produce pulsating high-speed water jets. The reason is that the introduction of pulsations into the water jets enables to increase their cutting efficiency due to the fact that the impact pressure (so-called water-hammer pressure) generated by an impact of slug of water on the target material is considerably higher than the stagnation pressure generated by corresponding continuous jet. Special method of pulsating jet generation was developed and tested extensively under the laboratory conditions at the Institute of Geonics in Ostrava. The method is based on the action of acoustic transducer on the pressure liquid and transmission of generated acoustic waves via pressure system to the nozzle. The purpose of the paper is to present results obtained during the research oriented at the determination of acoustic wave propagation in high-pressure system. The final objective of the research is to solve the problem of transmission of acoustic waves through high-pressure water to generate pulsating jet effectively even at larger distances from the acoustic source. In order to be able to simulate numerically acoustic wave propagation in the system, it is necessary among others to determine dependence of the sound speed and second kinematical viscosity on operating pressure. Method of determination of the second kinematical viscosity and speed of sound in liquid using modal analysis of response of the tube filled with liquid to the impact was developed. The response was measured by pressure sensors placed at both ends of the tube. Results obtained and presented in the paper indicate good agreement between experimental data and values of speed of sound calculated from so-called "UNESCO equation". They also show that the value of the second kinematical viscosity of water depends on the pressure.

  7. Scattering of Acoustic Waves from Ocean Boundaries

    DTIC Science & Technology

    2015-09-30

    of buried mines and improve SONAR performance in shallow water. OBJECTIVES 1) Determination of the correct physical model of acoustic propagation...Measurements for Range Dependent Geoacoustic Parameters: Bottom loss data from 5 – 30 kHz were collected as part of the Target and Reverberation Experiment...2013 (TREX13). These data were analyzed and range dependent geoacoustic parameters were derived for the TREX reverberation site including bottom loss

  8. A surface acoustic wave-driven micropump for particle uptake investigation under physiological flow conditions in very small volumes.

    PubMed

    Strobl, Florian G; Breyer, Dominik; Link, Phillip; Torrano, Adriano A; Bräuchle, Christoph; Schneider, Matthias F; Wixforth, Achim

    2015-01-01

    Static conditions represent an important shortcoming of many in vitro experiments on the cellular uptake of nanoparticles. Here, we present a versatile microfluidic device based on acoustic streaming induced by surface acoustic waves (SAWs). The device offers a convenient method for introducing fluid motion in standard cell culture chambers and for mimicking capillary blood flow. We show that shear rates over the whole physiological range in sample volumes as small as 200 μL can be achieved. A precise characterization method for the induced flow profile is presented and the influence of flow on the uptake of Pt-decorated CeO2 particles by endothelial cells (HMEC-1) is demonstrated. Under physiological flow conditions the particle uptake rates for this system are significantly lower than at low shear conditions. This underlines the vital importance of the fluidic environment for cellular uptake mechanisms.

  9. Subwavelength acoustic focusing by surface-wave-resonance enhanced transmission in doubly negative acoustic metamaterials

    SciTech Connect

    Zhou, Xiaoming; Badreddine Assouar, M. Oudich, Mourad

    2014-11-21

    We present analytical and numerical analyses of a yet unseen lensing paradigm that is based on a solid metamaterial slab in which the wave excitation source is attached. We propose and demonstrate sub-diffraction-limited acoustic focusing induced by surface resonant states in doubly negative metamaterials. The enhancement of evanescent waves across the metamaterial slab produced by their resonant coupling to surface waves is evidenced and quantitatively determined. The effect of metamaterial parameters on surface states, transmission, and wavenumber bandwidth is clearly identified. Based on this concept consisting of a wave source attached on the metamaterial, a high resolution of λ/28.4 is obtained with the optimum effective physical parameters, opening then an exciting way to design acoustic metamaterials for ultrasonic focused imaging.

  10. Inline SAW RFID tag using time position and phase encoding.

    PubMed

    Härmä, Sanna; Arthur, Wesley G; Hartmann, Clinton S; Maev, Roman G; Plessky, Victor P

    2008-08-01

    Surface acoustic wave (SAW) radio-frequency identification (RFID) tags are encoded according to partial reflections of an interrogation signal by short metal reflectors. The standard encryption method involves time position encoding that uses time delays of response signals. However, the data capacity of a SAW RFID tag can be significantly enhanced by extracting additional phase information from the tag responses. In this work, we have designed, using FEM-BEM simulations, and fabricated, on 128 degrees -LiNbO3, inline 2.44-GHz SAW RFID tag samples that combine time position and phase encoding. Each reflective echo has 4 possible time positions and a phase of 0 degrees , -90 degrees , -180 degrees , or -270 degrees. This corresponds to 16 different states, i.e., 4 bits of data, per code reflector. In addition to the enhanced data capacity, our samples also exhibit a low loss level of -38 dB for code reflections.

  11. Impact of Acoustic Standing Waves on Structural Responses: Reverberant Acoustic Testing (RAT) vs. Direct Field Acoustic Testing (DFAT)

    NASA Technical Reports Server (NTRS)

    Kolaini, Ali R.; Doty, Benjamin; Chang, Zensheu

    2012-01-01

    Loudspeakers have been used for acoustic qualification of spacecraft, reflectors, solar panels, and other acoustically responsive structures for more than a decade. Limited measurements from some of the recent speaker tests used to qualify flight hardware have indicated significant spatial variation of the acoustic field within the test volume. Also structural responses have been reported to differ when similar tests were performed using reverberant chambers. To address the impact of non-uniform acoustic field on structural responses, a series of acoustic tests were performed using a flat panel and a 3-ft cylinder exposed to the field controlled by speakers and repeated in a reverberant chamber. The speaker testing was performed using multi-input-single-output (MISO) and multi-input-multi-output (MIMO) control schemes with and without the test articles. In this paper the spatial variation of the acoustic field due to acoustic standing waves and their impacts on the structural responses in RAT and DFAT (both using MISO and MIMO controls for DFAT) are discussed in some detail.

  12. New piezoelectric materials for SAW filters

    NASA Astrophysics Data System (ADS)

    Anghelescu, Adrian; Nedelcu, Monica

    2010-11-01

    Scientific research of surface acoustic wave (SAW) devices had an early start by the end of 1960s and led to the development of high frequency and small size piezo devices. A sustained effort was dedicated for these components to be transformed into many more interesting applications for telecom market. Recently the employment of new piezo materials and crystallographic orientations open new opportunities for SAW filters. New piezoelectric crystals of gallium orthophosphate (GaPO4) provide higher electromechanical coupling than quartz, while maintaining temperature compensated characteristics similar to quartz. Based on this material phase transition of 970°C, development of new piezo devices to operate at higher temperatures up to 800°C can be done. SAW velocities about 30% lower than ST-X quartz, favors smaller and more compact devices. Other advantages of GaPO4 are: stability with high resistance to stress induced twinning, 3~4 times higher electromechanical coupling than quartz and existence of SAW temperature compensated orientations. Another family of new materials of the trigonal 32 class has received much attention recently because of their temperature behavior similar to quartz and the promise of higher electromechanical coupling coefficients. It is the family of langasite (LGS, La3Ga5SiO14), langatate (LGT, La3Ga5.5Ta0.5O14) and langanite (La3Ga5.5Nb0.5O14). Langasite crystals, easier to obtain and with the value of electromechanical coupling coefficient intermediate between quartz and lithium tantalate (k2=0.32% for 0°, 140°, 22.5° orientation and k2=0.38% for 0°, 140°, 25° orientation), enable us to design SAW filters with a relative pass band of 0.3% to 0.85%. Other piezoelectric materials are reviewed for comparison.

  13. Opportunities for shear energy scaling in bulk acoustic wave resonators.

    PubMed

    Jose, Sumy; Hueting, Raymond J E

    2014-10-01

    An important energy loss contribution in bulk acoustic wave resonators is formed by so-called shear waves, which are transversal waves that propagate vertically through the devices with a horizontal motion. In this work, we report for the first time scaling of the shear-confined spots, i.e., spots containing a high concentration of shear wave displacement, controlled by the frame region width at the edge of the resonator. We also demonstrate a novel methodology to arrive at an optimum frame region width for spurious mode suppression and shear wave confinement. This methodology makes use of dispersion curves obtained from finite-element method (FEM) eigenfrequency simulations for arriving at an optimum frame region width. The frame region optimization is demonstrated for solidly mounted resonators employing several shear wave optimized reflector stacks. Finally, the FEM simulation results are compared with measurements for resonators with Ta2O5/ SiO2 stacks showing suppression of the spurious modes.

  14. Surface wave acoustics of granular packing under gravity

    SciTech Connect

    Clement, Eric; Andreotti, Bruno; Bonneau, Lenaic

    2009-06-18

    Due to the non-linearity of Hertzian contacts, the speed of sound in granular matter increases with pressure. For a packing under gravity and in the presence of a free surface, bulk acoustic waves cannot propagate due to the inherent refraction toward the surface (the mirage effect). Thus, only modes corresponding to surface waves (Raleigh-Hertz modes) are able to propagate the acoustic signal. First, based on a non-linear elasticity model, we describe the main features associated to these surface waves. We show that under gravity, a granular packing is from the acoustic propagation point of view an index gradient waveguide that selects modes of two distinct families i.e. the sagittal and transverse waves localized in the vicinity of the free surface. A striking feature of these surface waves is the multi-modal propagation: for both transverse and sagittal waves, we show the existence of a infinite but discrete series of propagating modes. In each case, we determine the mode shape and and the corresponding dispersion relation. In the case of a finite size system, a geometric waveguide is superimposed to the index gradient wave guide. In this later case, the dispersion relations are modified by the appearance of a cut-off frequency that scales with depth. The second part is devoted to an experimental study of surface waves propagating in a granular packing confined in a long channel. This set-up allows to tune a monomodal emission by taking advantage of the geometric waveguide features combined with properly designed emitters. For both sagittal and transverses waves, we were able to isolate a single mode (the fundamental one) and to plot the dispersion relation. This measurements agree well with the Hertzian scaling law as predicted by meanfield models. Furthermore, it allows us to determine quantitatively relations on the elastic moduli. However, we observe that our data yield a shear modulus abnormally weak when compared to several meanfield predictions.

  15. Synchronization of self-excited dust acoustic waves

    NASA Astrophysics Data System (ADS)

    Suranga Ruhunusiri, W. D.; Goree, John

    2012-10-01

    Synchronization is a nonlinear phenomenon where a self-excited oscillation, like a wave in a plasma, interacts with an external driving, resulting in an adjustment of the oscillation frequency. Dust acoustic wave synchronization has been experimentally studied previously in laboratory and in microgravity conditions, e.g. [Pilch PoP 2009] and [Menzel PRL 2010]. We perform a laboratory experiment to study synchronization of self-excited dust acoustic waves. An rf glow discharge argon plasma is formed by applying a low power radio frequency voltage to a lower electrode. A 3D dust cloud is formed by levitating 4.83 micron microspheres inside a glass box placed on the lower electrode. Dust acoustic waves are self-excited with a natural frequency of 22 Hz due to an ion streaming instability. A cross section of the dust cloud is illuminated by a vertical laser sheet and imaged from the side with a digital camera. To synchronize the waves, we sinusoidally modulate the overall ion density. Differently from previous experiments, we use a driving electrode that is separate from the electrode that sustains the plasma, and we characterize synchronization by varying both driving amplitude and frequency.

  16. Single crystal metal wedges for surface acoustic wave propagation

    DOEpatents

    Fisher, E.S.

    1980-05-09

    An ultrasonic testing device has been developed to evaluate flaws and inhomogeneities in the near-surface region of a test material. A metal single crystal wedge is used to generate high frequency Rayleigh surface waves in the test material surface by conversion of a slow velocity, bulk acoustic mode in the wedge into a Rayleigh wave at the metal-wedge test material interface. Particular classes of metals have been found to provide the bulk acoustic modes necessary for production of a surface wave with extremely high frequency and angular collimation. The high frequency allows flaws and inhomogeneities to be examined with greater resolution. The high degree of angular collimation for the outgoing ultrasonic beam permits precision angular location of flaws and inhomogeneities in the test material surface.

  17. Analytical description of nonlinear acoustic waves in the solar chromosphere

    NASA Astrophysics Data System (ADS)

    Litvinenko, Yuri E.; Chae, Jongchul

    2017-02-01

    Aims: Vertical propagation of acoustic waves of finite amplitude in an isothermal, gravitationally stratified atmosphere is considered. Methods: Methods of nonlinear acoustics are used to derive a dispersive solution, which is valid in a long-wavelength limit, and a non-dispersive solution, which is valid in a short-wavelength limit. The influence of the gravitational field on wave-front breaking and shock formation is described. The generation of a second harmonic at twice the driving wave frequency, previously detected in numerical simulations, is demonstrated analytically. Results: Application of the results to three-minute chromospheric oscillations, driven by velocity perturbations at the base of the solar atmosphere, is discussed. Numerical estimates suggest that the second harmonic signal should be detectable in an upper chromosphere by an instrument such as the Fast Imaging Solar Spectrograph installed at the 1.6-m New Solar Telescope of the Big Bear Observatory.

  18. Single crystal metal wedges for surface acoustic wave propagation

    DOEpatents

    Fisher, Edward S.

    1982-01-01

    An ultrasonic testing device has been developed to evaluate flaws and inhomogeneities in the near-surface region of a test material. A metal single crystal wedge is used to generate high frequency Rayleigh surface waves in the test material surface by conversion of a slow velocity, bulk acoustic mode in the wedge into a Rayleigh wave at the metal-wedge test material interface. Particular classes of metals have been found to provide the bulk acoustic modes necessary for production of a surface wave with extremely high frequency and angular collimation. The high frequency allows flaws and inhomogeneities to be examined with greater resolution. The high degree of angular collimation for the outgoing ultrasonic beam permits precision angular location of flaws and inhomogeneities in the test material surface.

  19. Image reconstruction with acoustic radiation force induced shear waves

    NASA Astrophysics Data System (ADS)

    McAleavey, Stephen A.; Nightingale, Kathryn R.; Stutz, Deborah L.; Hsu, Stephen J.; Trahey, Gregg E.

    2003-05-01

    Acoustic radiation force may be used to induce localized displacements within tissue. This phenomenon is used in Acoustic Radiation Force Impulse Imaging (ARFI), where short bursts of ultrasound deliver an impulsive force to a small region. The application of this transient force launches shear waves which propagate normally to the ultrasound beam axis. Measurements of the displacements induced by the propagating shear wave allow reconstruction of the local shear modulus, by wave tracking and inversion techniques. Here we present in vitro, ex vivo and in vivo measurements and images of shear modulus. Data were obtained with a single transducer, a conventional ultrasound scanner and specialized pulse sequences. Young's modulus values of 4 kPa, 13 kPa and 14 kPa were observed for fat, breast fibroadenoma, and skin. Shear modulus anisotropy in beef muscle was observed.

  20. Homomorphic processing of the tube wave generated during acoustic logging

    SciTech Connect

    Ellefsen, K.J. ); Cheng, C.H. . Dept. of Earth, Atmospheric, and Planetary Sciences); Burns, D.R.

    1993-10-01

    The authors have developed a new method to process the tube wave, which is generated during acoustic logging, to obtain estimates for its wavenumber, attenuation coefficient, amplitude, and phase at every frequency. To improve the accuracy of the estimates, the method can use data from multiple sources and data collected at successive depths in the borehole. This new method has several advantages over other methods that are currently used to process acoustic logging data: the new method can obtain accurate estimates of the wavenumber and amplitude from only a few receivers; the receivers can be irregularly spaced; and no spurious estimates are generated. Nonetheless, this new method has one disadvantage compared to others: it can only estimate the parameters for one, high-amplitude wave like the tube wave. Also, like all other existing methods, the new method obtains only reasonable estimates for the attenuation coefficient when data from many receivers are processed.

  1. Improved equivalent circuits for acoustic plate wave devices.

    PubMed

    Zaitsev, B D; Kuznetsova, I E; Joshi, S G

    2002-05-01

    This paper presents improved equivalent circuits for the analysis and design of acoustic plate wave devices. The method uses a mixed equivalent circuit for the interdigital transducer consisting of both active and passive sections placed on the surface of a piezoelectric plate. The values of the various circuit elements are obtained by carrying out a best fit between theoretical and experimental frequency dependence of the real and imaginary parts of transducer input impedance. Knowledge of the equivalent circuit parameters allows one to optimize design of the devices. The method has been successfully employed for the design of one-port shear-horizontal wave resonators on Y-X lithium niobate plates. The proposed method can also be utilized for determining acoustic wave velocity with high accuracy.

  2. Excitation of Ion Acoustic Waves by Electron Beams

    NASA Astrophysics Data System (ADS)

    Sydorenko, Dmytro; Tokluoglu, Erinc; Kaganovich, Igor; Startsev, Edward; Davidson, Ronald

    2012-10-01

    The interaction of electron beams with plasmas is of considerable importance particularly for hybrid DC/RF coupled plasma sources used in plasma processing [1]. An electron beam is formed by emission from one surface, is accelerated through a dc bias electric field and enters the bulk plasma. Emitted electrons excite electron plasma (Langmuir) waves through the two-stream instability. Due to the high localized plasmon pressure, ion acoustic waves are excited parametrically. The plasma waves saturate by non-linear wave trapping. Eventually coupling between electron plasma waves and ion acoustic waves deteriorates the Langmuir waves, which leads to a bursting behavior. The two-stream instability and the consequent ion fluctuations are studied over a wide range of system parameters using the particle-in-cell codes EDIPIC and LSP. The influenceof these instabilities on collisionless electron heating are presented for a hybrid RF-DC plasma source.[4pt] [1] Lin Xu, et al, Appl. Phys. Lett., 93, 261502 (2008).

  3. Synchronized photonic modulators driven by surface acoustic waves.

    PubMed

    Crespo-Poveda, A; Hey, R; Biermann, K; Tahraoui, A; Santos, P V; Gargallo, B; Muñoz, P; Cantarero, A; de Lima, M M

    2013-09-09

    Photonic modulators are one of the most important elements of integrated photonics. We have designed, fabricated, and characterized a tunable photonic modulator consisting of two 180°-dephased output waveguide channels, driven by a surface acoustic wave in the GHz frequency range built on (Al,Ga)As. Odd multiples of the fundamental driven frequency are enabled by adjusting the applied acoustic power. A good agreement between theory and experimental results is achieved. The device can be used as a building block for more complex integrated functionalities and can be implemented in several material platforms.

  4. Coupling between ion-acoustic waves and neutrino oscillations.

    PubMed

    Haas, Fernando; Pascoal, Kellen Alves; Mendonça, José Tito

    2017-01-01

    The work investigates the coupling between ion-acoustic waves and neutrino flavor oscillations in a nonrelativistic electron-ion plasma under the influence of a mixed neutrino beam. Neutrino oscillations are mediated by the flavor polarization vector dynamics in a material medium. The linear dispersion relation around homogeneous static equilibria is developed. When resonant with the ion-acoustic mode, the neutrino flavor oscillations can transfer energy to the plasma exciting a new fast unstable mode in extreme astrophysical scenarios. The growth rate and the unstable wavelengths are determined in typical type II supernova parameters. The predictions can be useful for a new indirect probe on neutrino oscillations in nature.

  5. Coupling between ion-acoustic waves and neutrino oscillations

    NASA Astrophysics Data System (ADS)

    Haas, Fernando; Pascoal, Kellen Alves; Mendonça, José Tito

    2017-01-01

    The work investigates the coupling between ion-acoustic waves and neutrino flavor oscillations in a nonrelativistic electron-ion plasma under the influence of a mixed neutrino beam. Neutrino oscillations are mediated by the flavor polarization vector dynamics in a material medium. The linear dispersion relation around homogeneous static equilibria is developed. When resonant with the ion-acoustic mode, the neutrino flavor oscillations can transfer energy to the plasma exciting a new fast unstable mode in extreme astrophysical scenarios. The growth rate and the unstable wavelengths are determined in typical type II supernova parameters. The predictions can be useful for a new indirect probe on neutrino oscillations in nature.

  6. Full-circular surface acoustic wave excitation for high resolution acoustic microscopy using spherical lens and time gate technology.

    PubMed

    Ishikawa, I; Katakura, K; Ogura, Y

    1999-01-01

    With a fixed gate width under the condition where the focus of an acoustic lens was set inside the sample, we varied signal taking-in time. Discrimination was made between differences in time required for an ultrasonic signal reflected from the sample to reach the acoustic lens. This process also enabled three types of images to be obtained separately: the surface reflection wave image, a combination of images based on the interference of the surface reflection wave with surface acoustic waves, and the surface acoustic wave image. Thus it was presumed that this process also would reveal the causes of image contrast and allow an easy interpretation of images. Furthermore, the image resolution was improved, because the surface acoustic wave image was drawn by an ultrasonic beam produced by full-circular surface acoustic wave excitation propagating toward the center converging concentrically; the theoretical resolution was 0.4 times the value of the surface acoustic wave wavelength lambda(R) and independent of the defocus value of the acoustic lens. Several kinds of samples were observed with this method. The results showed that the new method permitted observation of the internal structures of samples while offering new knowledge through the data reflecting the ultrasonic wave damping and scatter drawn on the display.

  7. Making structured metals transparent for ultrabroadband electromagnetic waves and acoustic waves

    SciTech Connect

    Fan, Ren-Hao; Peng, Ru-Wen; Huang, Xian-Rong; Wang, Mu

    2015-07-15

    In this review, we present our recent work on making structured metals transparent for broadband electromagnetic waves and acoustic waves via excitation of surface waves. First, we theoretically show that one-dimensional metallic gratings can become transparent and completely antireflective for extremely broadband electromagnetic waves by relying on surface plasmons or spoof surface plasmons. Second, we experimentally demonstrate that metallic gratings with narrow slits are highly transparent for broadband terahertz waves at oblique incidence and high transmission efficiency is insensitive to the metal thickness. Further, we significantly develop oblique metal gratings transparent for broadband electromagnetic waves (including optical waves and terahertz ones) under normal incidence. In the third, we find the principles of broadband transparency for structured metals can be extended from one-dimensional metallic gratings to two-dimensional cases. Moreover, similar phenomena are found in sonic artificially metallic structures, which present the transparency for broadband acoustic waves. These investigations provide guidelines to develop many novel materials and devices, such as transparent conducting panels, antireflective solar cells, and other broadband metamaterials and stealth technologies. - Highlights: • Making structured metals transparent for ultrabroadband electromagnetic waves. • Non-resonant excitation of surface plasmons or spoof surface plasmons. • Sonic artificially metallic structures transparent for broadband acoustic waves.

  8. A three-microphone acoustic reflection technique using transmitted acoustic waves in the airway.

    PubMed

    Fujimoto, Yuki; Huang, Jyongsu; Fukunaga, Toshiharu; Kato, Ryo; Higashino, Mari; Shinomiya, Shohei; Kitadate, Shoko; Takahara, Yutaka; Yamaya, Atsuyo; Saito, Masatoshi; Kobayashi, Makoto; Kojima, Koji; Oikawa, Taku; Nakagawa, Ken; Tsuchihara, Katsuma; Iguchi, Masaharu; Takahashi, Masakatsu; Mizuno, Shiro; Osanai, Kazuhiro; Toga, Hirohisa

    2013-10-15

    The acoustic reflection technique noninvasively measures airway cross-sectional area vs. distance functions and uses a wave tube with a constant cross-sectional area to separate incidental and reflected waves introduced into the mouth or nostril. The accuracy of estimated cross-sectional areas gets worse in the deeper distances due to the nature of marching algorithms, i.e., errors of the estimated areas in the closer distances accumulate to those in the further distances. Here we present a new technique of acoustic reflection from measuring transmitted acoustic waves in the airway with three microphones and without employing a wave tube. Using miniaturized microphones mounted on a catheter, we estimated reflection coefficients among the microphones and separated incidental and reflected waves. A model study showed that the estimated cross-sectional area vs. distance function was coincident with the conventional two-microphone method, and it did not change with altered cross-sectional areas at the microphone position, although the estimated cross-sectional areas are relative values to that at the microphone position. The pharyngeal cross-sectional areas including retropalatal and retroglossal regions and the closing site during sleep was visualized in patients with obstructive sleep apnea. The method can be applicable to larger or smaller bronchi to evaluate the airspace and function in these localized airways.

  9. Diffraction of dust acoustic waves by a circular cylinder

    SciTech Connect

    Kim, S.-H.; Heinrich, J. R.; Merlino, R. L.

    2008-09-15

    The diffraction of dust acoustic (DA) waves around a long dielectric rod is observed using video imaging methods. The DA waves are spontaneously excited in a dusty plasma produced in a direct current glow discharge plasma. The rod acquires a negative charge that produces a coaxial dust void around it. The diameter of the void is the effective size of the 'obstacle' encountered by the waves. The wavelength of the DA waves is approximately the size of the void. The observations are considered in relation to the classical problem of the diffraction of sound waves from a circular cylinder, a problem first analyzed by Lord Rayleigh [Theory of Sound, 2nd ed. (MacMillan, London, 1896)].

  10. Nonlinear electron acoustic waves in presence of shear magnetic field

    SciTech Connect

    Dutta, Manjistha; Khan, Manoranjan; Ghosh, Samiran; Chakrabarti, Nikhil

    2013-12-15

    Nonlinear electron acoustic waves are studied in a quasineutral plasma in the presence of a variable magnetic field. The fluid model is used to describe the dynamics of two temperature electron species in a stationary positively charged ion background. Linear analysis of the governing equations manifests dispersion relation of electron magneto sonic wave. Whereas, nonlinear wave dynamics is being investigated by introducing Lagrangian variable method in long wavelength limit. It is shown from finite amplitude analysis that the nonlinear wave characteristics are well depicted by KdV equation. The wave dispersion arising in quasineutral plasma is induced by transverse magnetic field component. The results are discussed in the context of plasma of Earth's magnetosphere.

  11. Acoustic solitons: A robust tool to investigate the generation and detection of ultrafast acoustic waves

    NASA Astrophysics Data System (ADS)

    Péronne, Emmanuel; Chuecos, Nicolas; Thevenard, Laura; Perrin, Bernard

    2017-02-01

    Solitons are self-preserving traveling waves of great interest in nonlinear physics but hard to observe experimentally. In this report an experimental setup is designed to observe and characterize acoustic solitons in a GaAs(001) substrate. It is based on careful temperature control of the sample and an interferometric detection scheme. Ultrashort acoustic solitons, such as the one predicted by the Korteweg-de Vries equation, are observed and fully characterized. Their particlelike nature is clearly evidenced and their unique properties are thoroughly checked. The spatial averaging of the soliton wave front is shown to account for the differences between the theoretical and experimental soliton profile. It appears that ultrafast acoustic experiments provide a precise measurement of the soliton velocity. It allows for absolute calibration of the setup as well as the response function analysis of the detection layer. Moreover, the temporal distribution of the solitons is also analyzed with the help of the inverse scattering method. It shows how the initial acoustic pulse profile which gives birth to solitons after nonlinear propagation can be retrieved. Such investigations provide a new tool to probe transient properties of highly excited matter through the study of the emitted acoustic pulse after laser excitation.

  12. Inverse Scattering Problems for Acoustic Waves in AN Inhomogeneous Medium.

    NASA Astrophysics Data System (ADS)

    Kedzierawski, Andrzej Wladyslaw

    1990-01-01

    This dissertation considers the inverse scattering problem of determining either the absorption of sound in an inhomogeneous medium or the surface impedance of an obstacle from a knowledge of the far-field patterns of the scattered fields corresponding to many incident time -harmonic plane waves. First, we consider the inverse problem in the case when the scattering object is an inhomogeneous medium with complex refraction index having compact support. Our approach to this problem is the orthogonal projection method of Colton-Monk (cf. The inverse scattering problem for time acoustic waves in an inhomogeneous medium, Quart. J. Mech. Appl. Math. 41 (1988), 97-125). After that, we prove the analogue of Karp's Theorem for the scattering of acoustic waves through an inhomogeneous medium with compact support. We then generalize some of these results to the case when the inhomogeneous medium is no longer of compact support. If the acoustic wave penetrates the inhomogeneous medium by only a small amount then the inverse medium problem leads to the inverse obstacle problem with an impedance boundary condition. We solve the inverse impedance problem of determining the surface impedance of an obstacle of known shape by using both the methods of Kirsch-Kress and Colton-Monk (cf. R. Kress, Linear Integral Equations, Springer-Verlag, New York, 1989).

  13. A frequency selective acoustic transducer for directional Lamb wave sensing.

    PubMed

    Senesi, Matteo; Ruzzene, Massimo

    2011-10-01

    A frequency selective acoustic transducer (FSAT) is proposed for directional sensing of guided waves. The considered FSAT design is characterized by a spiral configuration in wavenumber domain, which leads to a spatial arrangement of the sensing material producing output signals whose dominant frequency component is uniquely associated with the direction of incoming waves. The resulting spiral FSAT can be employed both for directional sensing and generation of guided waves, without relying on phasing and control of a large number of channels. The analytical expression of the shape of the spiral FSAT is obtained through the theoretical formulation for continuously distributed active material as part of a shaped piezoelectric device. Testing is performed by forming a discrete array through the points of the measurement grid of a scanning laser Doppler vibrometer. The discrete array approximates the continuous spiral FSAT geometry, and provides the flexibility to test several configurations. The experimental results demonstrate the strong frequency dependent directionality of the spiral FSAT and suggest its application for frequency selective acoustic sensors, to be employed for the localization of broadband acoustic events, or for the directional generation of Lamb waves for active interrogation of structural health.

  14. Surface-acoustic-wave study of defects in GaAs grown by molecular-beam epitaxy at 220 degree C

    SciTech Connect

    Khachaturyan, K.; Weber, E.R. Materials Science Division, Lawrence Berkeley Laboratory, Berkeley, California 94720 ); White, R.M. )

    1992-02-15

    Surface acoustic waves (SAW's) were used to study the influence of defects on the elastic properties of epitaxial films of semiconductors. The object of this study was As-rich GaAs grown by molecular-beam-epitaxy at 220 {degree}C. The SAW velocity on 0.3-wavelength-thick epilayers was 1.2% smaller than on the substrate alone. That velocity difference decreased after loss of some excess As as a result of 350 {degree}C--435 {degree}C anneals. A persistent increase as much as 0.4% of the SAW velocity at low temperatures was observed after illumination; this increase could be quenched by annealing at 120--130 K. This behavior is caused by the metastable transition of EL2-like As{sub Ga} defects and constitutes the direct experimental proof of the illumination-induced large lattice relaxation of this defect. The SAW velocity increase was correlated with the persistent bleaching of EL2-related optical absorption. The spectral dependence of rate of illumination-induced SAW velocity increase was measured.

  15. Envelope solitons of acoustic plate modes and surface waves.

    PubMed

    Mayer, Andreas P; Kovalev, Alexander S

    2003-06-01

    The problem of the existence of evelope solitons in elastic plates and at solid surfaces covered by an elastic film is revisited with special attention paid to nonlinear long-wave short-wave interactions. Using asymptotic expansions and multiple scales, conditions for the existence of envelope solitons are established and it is shown how their parameters can be expressed in terms of the elastic moduli and mass densities of the materials involved. In addition to homogeneous plates, weak periodic modulation of the plate's material parameters are also considered. In the case of wave propagation in an elastic plate, modulations of weakly nonlinear carrier waves are governed by a coupled system of partial differential equations consisting of evolution equations for the complex amplitude of the carrier wave (the nonlinear Schrödinger equation for envelope solitons and the Mills-Trullinger equations for gap solitons), and the wave equation for long-wavelength acoustic plate modes. In contrast to this situation, envelope solitons of surface acoustic waves in a layered structure are normally described by the nonlinear Schrödinger equation alone. However, at higher orders of the carrier wave amplitude, the envelope soliton is found to be accompanied by a quasistatic long-wavelength strain field, which may be localized at the surface with penetration depth into the substrate of the order of the inverse amplitude or which may radiate energy into the bulk. A new set of modulation equations is derived for the resonant case of the carrier wave's group velocity being equal to the phase velocity of long-wavelength Rayleigh waves of the uncoated substrate.

  16. A laser probe based on a Sagnac interferometer with fast mechanical scan for RF surface and bulk acoustic wave devices.

    PubMed

    Hashimoto, Ken-ya; Kashiwa, Keiskue; Wu, Nan; Omori, Tatsuya; Yamaguchi, Masatsune; Takano, Osamu; Meguro, Sakae; Akahane, Koichi

    2011-01-01

    This paper describes the development of a phasesensitive laser probe with fast mechanical scan for RF surface and bulk acoustic wave (SAW/BAW) devices. The Sagnac interferometer composed of micro-optic elements was introduced for the selective detection of RF vertical motion associated with RF SAW/BAW propagation and vibration. A high-pass characteristic of the interferometer makes the measurement very insensitive to low-frequency vibration. This feature allows us to apply the fast mechanical scan to the interferometric measurement without badly sacrificing its SNR and spatial resolution. The system was applied to the visualization of a field pattern on the vibrating surface of an RF BAW resonator operating in the 2 GHz range. The field pattern was obtained in 17 min as a 2-D image (500 × 750 pixel with 0.4 μm resolution and SNR of 40 dB). The system was also applied to the characterization of an RF SAW resonator operating in the 1 GHz range, and the applicability of the system was demonstrated.

  17. A centrifugally actuated point-of-care testing system for the surface acoustic wave immunosensing of cardiac troponin I.

    PubMed

    Lee, Woochang; Jung, Jaeyeon; Hahn, Young Ki; Kim, Sang Kyu; Lee, Yeolho; Lee, Joonhyung; Lee, Tae-Han; Park, Jin-Young; Seo, Hyejung; Lee, Jung Nam; Oh, Jin Ho; Choi, Youn-Suk; Lee, Soo Suk

    2013-05-07

    A fully automated point-of-care testing (POCT) system with a surface acoustic wave (SAW) immunosensor was developed for rapid and sensitive detection of cardiac troponin I (cTnI) in body fluid (plasma and whole blood). The assay, based on gold nanoparticle sandwich immunoassay and subsequent gold staining, was performed on the SAW immunosensor packaged inside a disposable microfluidic cartridge. The entire fluidic process, including plasma separation, reagent transport, metering, and mixing, was carried out by controlling the centrifugal force acting on the rotating cartridge and laser-irradiated ferrowax microvalves. On investigation of sensor response to various cTnI concentrations, the system exhibited a high performance with a detection limit of 6.7 pg mL(-1), and the coefficient of variation was less than 10% over the entire test range (10 pg mL(-1) to 25 ng mL(-1)). On comparing this POCT system with a clinically utilized system in a physical laboratory (Centaur® XP; Siemens), a correlation coefficient of 0.998 was found, validating the diagnostic capability of the SAW immunosensor.

  18. Determination of elastic properties of a MnO2 coating by surface acoustic wave velocity dispersion analysis

    NASA Astrophysics Data System (ADS)

    Sermeus, J.; Sinha, R.; Vanstreels, K.; Vereecken, P. M.; Glorieux, C.

    2014-07-01

    MnO2 is a material of interest in the development of high energy-density batteries, specifically as a coating material for internal 3D structures, thus ensuring rapid energy deployment. Its electrochemical properties have been mapped extensively, but there are, to the best of the authors' knowledge, no records of the elastic properties of thin film MnO2. Impulsive stimulated thermal scattering (ISTS), also known as the heterodyne diffraction or transient grating technique, was used to determine the Young's modulus (E) and porosity (ψ) of a 500 nm thick MnO2 coating on a Si(001) substrate. ISTS is an all optical method that is able to excite and detect surface acoustic waves (SAWs) on opaque samples. From the measured SAW velocity dispersion, the Young's modulus and porosity were determined to be E = 25 ± 1 GPa and ψ = 42 ± 1 %, respectively. These values were confirmed by independent techniques and determined by a most-squares analysis of the carefully fitted SAW velocity dispersion. This study demonstrates the ability of the presented technique to determine the elastic parameters of a thin, porous film on an anisotropic substrate.

  19. Active micro-mixers using surface acoustic waves on Y-cut 128° LiNbO3

    NASA Astrophysics Data System (ADS)

    Tseng, Wei-Kuo, Jr.; Lin, Lung; Sung, Wang-Chou; Chen, Shu-Hui; Lee, Gwo-Bin

    2006-03-01

    This study presents an active method for micro-mixers using surface acoustic waves (SAW) to rapidly mix co-fluent fluids. Mixing is challenging work in microfluidic systems due to their low-Reynolds-number flow conditions. SAW devices were fabricated on 128° Y-cut lithium niobate (LiNbO3). The micro-mixers are these piezoelectric actuators integrated with polydimethylsiloxane microchannels. The effects of the applied voltages on interdigitated transducers (IDTs) and two layouts, parallel- and transversal-type, of micro-mixers on the mixing performance were experimentally explored. The experimental results revealed that the parallel-type mixer achieved a higher mixing effect. Meanwhile, a higher applied voltage on the IDTs led to a significant improvement in the mixing performance of the active micro-mixer. Typical temperature effects associated with the applied voltages on the IDTs were also investigated. Finally, a digestion reaction between a protein (hemoglobin) and an enzyme (trypsin) was performed to verify the capability of the micro-mixers. The protein-enzyme mixture was qualitatively analyzed using mass spectrometry. Using these SAW-based mixers, the amount of digested peptides increased. Additionally, the protein-enzyme mixture was also quantitatively analyzed using high-performance liquid chromatography. Experimental data showed that the amount of digested peptides increased 21.1% using the active mixer. Therefore, the developed micro-mixers can be applied in microfluidic systems for improving mixing efficiency and thus enhancing the bio-reaction.

  20. Z-path SAW RFID tag.

    PubMed

    Härmä, Sanna; Plessky, Victor P; Hartmann, Clinton S; Steichen, William

    2008-01-01

    Surface acoustic wave (SAW) radio-frequency identification (RFID) tags are soon expected to be produced in very high volumes. The size and cost of a SAW RFID tag will be key parameters for many applications. Therefore, it is of primary importance to reduce the chip size. In this work, we describe the design principles of a 2.4-GHz SAW RFID tag that is significantly smaller than earlier reported tags. We also present simulated and experimental results. The coded signal should arrive at the reader with a certain delay (typically about 1 micros), i.e., after the reception of environmental echoes. If the tag uses a bidirectional interdigital transducer (IDT), space for the initial delay is needed on both sides of the IDT. In this work, we replace the bidirectional IDT by a unidirectional one. This halves the space required by the initial delay because all the code reflectors must now be placed on the same side of the IDT. We reduce tag size even further by using a Z-path geometry in which the same space in x-direction is used for both the initial delay and the code reflectors. Chip length is thus determined only by the space required by the code reflectors.

  1. Mercury Sorption and Desorption on Gold: A Comparative Analysis of Surface Acoustic Wave and Quartz Crystal Microbalance-Based Sensors.

    PubMed

    Kabir, K M Mohibul; Sabri, Ylias M; Esmaielzadeh Kandjani, Ahmad; Matthews, Glenn I; Field, Matthew; Jones, Lathe A; Nafady, Ayman; Ippolito, Samuel J; Bhargava, Suresh K

    2015-08-04

    Microelectromechanical sensors based on surface acoustic wave (SAW) and quartz crystal microbalance (QCM) transducers possess substantial potential as online elemental mercury (Hg(0)) vapor detectors in industrial stack effluents. In this study, a comparison of SAW- and QCM-based sensors is performed for the detection of low concentrations of Hg(0) vapor (ranging from 24 to 365 ppbv). Experimental measurements and finite element method (FEM) simulations allow the comparison of these sensors with regard to their sensitivity, sorption and desorption characteristics, and response time following Hg(0) vapor exposure at various operating temperatures ranging from 35 to 75 °C. Both of the sensors were fabricated on quartz substrates (ST and AT cut quartz for SAW and QCM devices, respectively) and employed thin gold (Au) layers as the electrodes. The SAW-based sensor exhibited up to ∼111 and ∼39 times higher response magnitudes than did the QCM-based sensor at 35 and 55 °C, respectively, when exposed to Hg(0) vapor concentrations ranging from 24 to 365 ppbv. The Hg(0) sorption and desorption calibration curves of both sensors were found to fit well with the Langmuir extension isotherm at different operating temperatures. Furthermore, the Hg(0) sorption and desorption rate demonstrated by the SAW-based sensor was found to decrease as the operating temperature increased, while the opposite trend was observed for the QCM-based sensor. However, the SAW-based sensor reached the maximum Hg(0) sorption rate faster than the QCM-based sensor regardless of operating temperature, whereas both sensors showed similar response times (t90) at various temperatures. Additionally, the sorption rate data was utilized in this study in order to obtain a faster response time from the sensor upon exposure to Hg(0) vapor. Furthermore, comparative analysis of the developed sensors' selectivity showed that the SAW-based sensor had a higher overall selectivity (90%) than did the QCM

  2. Standing wave acoustic levitation on an annular plate

    NASA Astrophysics Data System (ADS)

    Kandemir, Mehmet Hakan; Çalışkan, Mehmet

    2016-11-01

    In standing wave acoustic levitation technique, a standing wave is formed between a source and a reflector. Particles can be attracted towards pressure nodes in standing waves owing to a spring action through which particles can be suspended in air. This operation can be performed on continuous structures as well as in several numbers of axes. In this study an annular acoustic levitation arrangement is introduced. Design features of the arrangement are discussed in detail. Bending modes of the annular plate, known as the most efficient sound generation mechanism in such structures, are focused on. Several types of bending modes of the plate are simulated and evaluated by computer simulations. Waveguides are designed to amplify waves coming from sources of excitation, that are, transducers. With the right positioning of the reflector plate, standing waves are formed in the space between the annular vibrating plate and the reflector plate. Radiation forces are also predicted. It is demonstrated that small particles can be suspended in air at pressure nodes of the standing wave corresponding to a particular bending mode.

  3. Dust acoustic waves in strongly coupled dissipative plasmas

    NASA Astrophysics Data System (ADS)

    Xie, B. S.; Yu, M. Y.

    2000-12-01

    The theory of dust acoustic waves is revisited in the frame of the generalized viscoelastic hydrodynamic theory for highly correlated dusts. Physical processes relevant to many experiments on dusts in plasmas, such as ionization and recombination, dust-charge variation, elastic electron and ion collisions with neutral and charged dust particles, as well as relaxation due to strong dust coupling, are taken into account. These processes can be on similar time scales and are thus important for the conservation of particles and momenta in a self-consistent description of the system. It is shown that the dispersion properties of the dust acoustic waves are determined by a sensitive balance of the effects of strong dust coupling and collisional relaxation. The predictions of the present theory applicable to typical parameters in laboratory strongly coupled dusty plasmas are given and compared with the experiment results. Some possible implications and discrepanies between theory and experiment are also discussed.

  4. HF Doppler observations of acoustic waves excited by the earthquake

    NASA Technical Reports Server (NTRS)

    Ichinose, T.; Takagi, K.; Tanaka, T.; Okuzawa, T.; Shibata, T.; Sato, Y.; Nagasawa, C.; Ogawa, T.

    1985-01-01

    Ionospheric disturbances caused by the earthquake of a relatively small and large epicentral distance have been detected by a network of HF-Doppler sounders in central Japan and Kyoto station, respectively. The HF-Doppler data of a small epicentral distance, together with the seismic data, have been used to formulate a mechanism whereby ionospheric disturbances are produced by the Urakawa-Oki earthquake in Japan. Comparison of the dynamic spectra of these data has revealed experimentally that the atmosphere acts as a low-pass filter for upward-propagating acoustic waves. By surveying the earthquakes for which the magnitude M is larger than 6.0, researchers found the ionospheric effect in 16 cases of 82 seismic events. As almost all these effects have occurred in the daytime, it is considered that it may result from the filtering effect of the upward-propagating acoustic waves.

  5. Reflection and transmission of acoustic waves from a moving layer

    NASA Technical Reports Server (NTRS)

    Steinmetz, G. G.; Singh, J. J.

    1972-01-01

    The refraction of acoustic waves by a moving medium layer is theoretically treated and the expressions for reflection and transmission coefficients are determined. The moving medium layer velocity is assumed to have a space dependence in one direction. A partitioning of the moving medium layer into constant-velocity sublayers is introduced and the number of sublayers is allowed to increase until the reflection and transmission coefficients converage to their respective values. Numerical results for several sublayer approximations of Poiseuille's flow are presented as functions of the moving layer velocity for several angles of incidence of the acoustic wave. The degenerate case of single constant-velocity layer is also treated, both theoretically and by a numerical analysis.

  6. Laser-generated acoustic wave studies on tattoo pigment

    NASA Astrophysics Data System (ADS)

    Paterson, Lorna M.; Dickinson, Mark R.; King, Terence A.

    1996-01-01

    A Q-switched alexandrite laser (180 ns at 755 nm) was used to irradiate samples of agar embedded with red, black and green tattoo dyes. The acoustic waves generated in the samples were detected using a PVDF membrane hydrophone and compared to theoretical expectations. The laser pulses were found to generate acoustic waves in the black and green samples but not in the red pigment. Pressures of up to 1.4 MPa were produced with irradiances of up to 96 MWcm-2 which is comparable to the irradiances used to clear pigment embedded in skin. The pressure gradient generated across pigment particles was approximately 1.09 X 1010 Pam-1 giving a pressure difference of 1.09 +/- 0.17 MPa over a particle with mean diameter 100 micrometers . This is not sufficient to permanently damage skin which has a tensile strength of 7.4 MPa.

  7. On-line surveillance of lubricants in bearings by means of surface acoustic waves.

    PubMed

    Lindner, Gerhard; Schmitt, Martin; Schubert, Josephine; Krempel, Sandro; Faustmann, Hendrik

    2010-01-01

    The acoustic wave propagation in bearings filled with lubricants and driven by pulsed excitation of surface acoustic waves has been investigated with respect to the presence and the distribution of different lubricants. Experimental setups, which are based on the mode conversion between surface acoustic waves and compression waves at the interface between a solid substrate of the bearing and a lubricant are described. The results of preliminary measurements at linear friction bearings, rotation ball bearings and axial cylinder roller bearings are presented.

  8. Acoustic field of a ballistic shock wave therapy device.

    PubMed

    Cleveland, Robin O; Chitnis, Parag V; McClure, Scott R

    2007-08-01

    Shock wave therapy (SWT) refers to the use of focused shock waves for treatment of musculoskeletal indications including plantar fascitis and dystrophic mineralization of tendons and joint capsules. Measurements were made of a SWT device that uses a ballistic source. The ballistic source consists of a handpiece within which compressed air (1-4 bar) is used to fire a projectile that strikes a metal applicator placed on the skin. The projectile generates stress waves in the applicator that transmit as pressure waves into tissue. The acoustic fields from two applicators were measured: one applicator was 15 mm in diameter and the surface slightly convex and the second was 12 mm in diameter the surface was concave. Measurements were made in a water tank and both applicators generated a similar pressure pulse consisting of a rectangular positive phase (4 micros duration and up to 8 MPa peak pressure) followed by a predominantly negative tail (duration of 20 micros and peak negative pressure of -6 MPa), with many oscillations. The rise times of the waveforms were around 1 micros and were shown to be too long for the pulses to be considered shock waves. Measurements of the field indicated that region of high pressure was restricted to the near-field (20-40 mm) of the source and was consistent with the Rayleigh distance. The measured acoustic field did not display focusing supported by calculations, which demonstrated that the radius of curvature of the concave surface was too large to effect a focusing gain. Other SWT devices use electrohydraulic, electromagnetic and piezoelectric sources that do result in focused shock waves. This difference in the acoustic fields means there is potentially a significant mechanistic difference between a ballistic source and other SWT devices.

  9. Microfluidic integrated acoustic waving for manipulation of cells and molecules.

    PubMed

    Barani, Alireza; Paktinat, Hossein; Janmaleki, Mohsen; Mohammadi, Aminollah; Mosaddegh, Peiman; Fadaei-Tehrani, Alireza; Sanati-Nezhad, Amir

    2016-11-15

    Acoustophoresis with its simple and low-cost fabrication, rapid and localized fluid actuation, compatibility with microfluidic components, and biocompatibility for cellular studies, has been extensively integrated into microfluidics to provide on-chip microdevices for a variety of applications in biology, bioengineering and chemistry. Among different applications, noninvasive manipulation of cells and biomolecules are significantly important, which are addressed by acoustic-based microfluidics. Here in this paper, we briefly explain the principles and different configurations of acoustic wave and acoustic streaming for the manipulation of cells and molecules and overview its applications for single cell isolation, cell focusing and sorting, cell washing and patterning, cell-cell fusion and communication, and tissue engineering. We further discuss the application of acoustic-based microfluidic systems for the mixing and transport of liquids, manipulation of deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) molecules, followed by explanation on the present challenges of acoustic-based microfluidics for the handling of cells and molecules, and highlighting the future directions.

  10. Impact of Acoustic Standing Waves on Structural Responses

    NASA Technical Reports Server (NTRS)

    Kolaini, Ali R.

    2014-01-01

    For several decades large reverberant chambers and most recently direct field acoustic testing have been used in the aerospace industry to test larger structures with low surface densities such as solar arrays and reflectors to qualify them and to detect faults in the design and fabrication. It has been reported that in reverberant chamber and direct acoustic testing, standing acoustic modes may strongly couple with the fundamental structural modes of the test hardware (Reference 1). In this paper results from a recent reverberant chamber acoustic test of a composite reflector are discussed. These results provide further convincing evidence of the acoustic standing wave and structural modes coupling phenomenon. The purpose of this paper is to alert test organizations to this phenomenon so that they can account for the potential increase in structural responses and ensure that flight hardware undergoes safe testing. An understanding of the coupling phenomenon may also help minimize the over and/or under testing that could pose un-anticipated structural and flight qualification issues.

  11. High-resolution, high-linearity temperature sensor using surface acoustic wave device based on LiNbO3/SiO2/Si substrate

    NASA Astrophysics Data System (ADS)

    Tian, Xiang-Guang; Liu, Heng; Tao, Lu-Qi; Yang, Yi; Jiang, Hanjun; Ren, Tian-Ling

    2016-09-01

    A high-resolution and high-linearity surface acoustic wave (SAW) temperature sensor, consisting of a SAW resonator device fabricated on novel X-cut LiNbO3/SiO2/Si piezoelectric substrate and a resonance frequency readout chip using standard 180 nm CMOS technology, is presented for the first time. High temperature performance substrate LiNbO3/SiO2/Si is prepared mainly by ion implantation and wafer bonding at first. RF SAW device with resonance frequency near 900 MHz is designed and fabricated on the substrate. Traditional probe method using network analyzer and the readout chip method are both implemented to characterize the fabricated SAW device. Further measurement of temperature using resonance frequency shift of SAW device demonstrates the feasibility of the combined system as a portable SAW temperature sensor. The obtained frequency-temperature relation of the fabricated device is almost linear. The frequency resolution of the readout chip is 733 Hz and the corresponding temperature accuracy is 0.016 ° C. Resolution of the sensor in this work is superior to most of the commercial temperature measurement sensors. Theory analysis and finite element simulation are also presented to prove the mechanism and validity of using SAW device for temperature detection applications. We conclude that the high-linearity frequency-temperature relation is achieved by the offset between high-order coefficients of LiNbO3 and SiO2 with opposite signs. This work offers the possibility of temperature measuring in ultra-high precision sensing and control applications.

  12. Surface acoustic wave probe implant for predicting epileptic seizures

    DOEpatents

    Gopalsami, Nachappa [Naperville, IL; Kulikov, Stanislav [Sarov, RU; Osorio, Ivan [Leawood, KS; Raptis, Apostolos C [Downers Grove, IL

    2012-04-24

    A system and method for predicting and avoiding a seizure in a patient. The system and method includes use of an implanted surface acoustic wave probe and coupled RF antenna to monitor temperature of the patient's brain, critical changes in the temperature characteristic of a precursor to the seizure. The system can activate an implanted cooling unit which can avoid or minimize a seizure in the patient.

  13. Application of guided acoustic waves to delamination detection

    NASA Technical Reports Server (NTRS)

    Sun, Keun J.

    1992-01-01

    Guided plate waves are able to interact with structural flaws such as delaminations and cracks due to their propagation properties highly sensitive to the thickness change in materials. A technique which employs an acoustic damper to probe the results of this interaction and then to locate flaws in a relatively short period of time is developed. With its technical advantages, this technique shows its potential application to large area structural integrity assessment.

  14. Space manufacturing of surface acoustic wave devices, appendix D

    NASA Technical Reports Server (NTRS)

    Sardella, G.

    1973-01-01

    Space manufacturing of transducers in a vibration free environment is discussed. Fabrication of the masks, and possible manufacturing of the surface acoustic wave components aboard a space laboratory would avoid the inherent ground vibrations and the frequency limitation imposed by a seismic isolator pad. The manufacturing vibration requirements are identified. The concepts of space manufacturing are analyzed. A development program for manufacturing transducers is recommended.

  15. R&D 100 Winner 2010: Acoustic Wave Biosensors

    SciTech Connect

    Larson, Richard; Branch, Darren; Edwards, Thayne

    2016-06-07

    The acoustic wave biosensor is innovative device that is a handheld, battery-powered, portable detection system capable of multiplex identification of a wide range of medically relevant pathogens and their biomolecular signatures — viruses, bacteria, proteins, and DNA — at clinically relevant levels. This detection occurs within minutes — not hours — at the point of care, whether that care is in a physician's office, a hospital bed, or at the scene of a biodefense or biomedical emergency.

  16. Development of High Precision Metal Micro-Electro-Mechanical-Systems Column for Portable Surface Acoustic Wave Gas Chromatograph

    NASA Astrophysics Data System (ADS)

    Iwaya, Takamitsu; Akao, Shingo; Sakamoto, Toshihiro; Tsuji, Toshihiro; Nakaso, Noritaka; Yamanaka, Kazushi

    2012-07-01

    In the field of environmental measurement and security, a portable gas chromatograph (GC) is required for the on-site analysis of multiple hazardous gases. Although the gas separation column has been downsized using micro-electro-mechanical-systems (MEMS) technology, an MEMS column made of silicon and glass still does not have sufficient robustness and a sufficiently low fabrication cost for a portable GC. In this study, we fabricated a robust and inexpensive high-precision metal MEMS column by combining diffusion-bonded etched stainless-steel plates with alignment evaluation using acoustic microscopy. The separation performance was evaluated using a desktop GC with a flame ionization detector and we achieved the high separation performance comparable to the best silicon MEMS column fabricated using a dynamic coating method. As an application, we fabricated a palm-size surface acoustic wave (SAW) GC combining this column with a ball SAW sensor and succeeded in separating and detecting a mixture of volatile organic compounds.

  17. Dynamics of sessile and pendant drops excited by surface acoustic waves: Gravity effects and correlation between oscillatory and translational motions.

    PubMed

    Bussonnière, A; Baudoin, M; Brunet, P; Matar, O Bou

    2016-05-01

    When sessile droplets are excited by ultrasonic traveling surface acoustic waves (SAWs), they undergo complex dynamics with both oscillations and translational motion. While the nature of the Rayleigh-Lamb quadrupolar drop oscillations has been identified, their origin and their influence on the drop mobility remains unexplained. Indeed, the physics behind this peculiar dynamics is complex with nonlinearities involved both at the excitation level (acoustic streaming and radiation pressure) and in the droplet response (nonlinear oscillations and contact line dynamics). In this paper, we investigate the dynamics of sessile and pendant drops excited by SAWs. For pendant drops, so-far unreported dynamics are observed close to the drop detachment threshold with the suppression of the translational motion. Away from this threshold, the comparison between pendant and sessile drop dynamics allows us to identify the role played by gravity or, more generally, by an initial or dynamically induced stretching of the drop. In turn, we elucidate the origin of the resonance frequency shift, as well as the origin of the strong correlation between oscillatory and translational motion. We show that for sessile drops, the velocity is mainly determined by the amplitude of oscillation and that the saturation observed is due to the nonlinear dependence of the drop response frequency on the dynamically induced stretching.

  18. Dynamics of sessile and pendant drops excited by surface acoustic waves: Gravity effects and correlation between oscillatory and translational motions

    NASA Astrophysics Data System (ADS)

    Bussonnière, A.; Baudoin, M.; Brunet, P.; Matar, O. Bou

    2016-05-01

    When sessile droplets are excited by ultrasonic traveling surface acoustic waves (SAWs), they undergo complex dynamics with both oscillations and translational motion. While the nature of the Rayleigh-Lamb quadrupolar drop oscillations has been identified, their origin and their influence on the drop mobility remains unexplained. Indeed, the physics behind this peculiar dynamics is complex with nonlinearities involved both at the excitation level (acoustic streaming and radiation pressure) and in the droplet response (nonlinear oscillations and contact line dynamics). In this paper, we investigate the dynamics of sessile and pendant drops excited by SAWs. For pendant drops, so-far unreported dynamics are observed close to the drop detachment threshold with the suppression of the translational motion. Away from this threshold, the comparison between pendant and sessile drop dynamics allows us to identify the role played by gravity or, more generally, by an initial or dynamically induced stretching of the drop. In turn, we elucidate the origin of the resonance frequency shift, as well as the origin of the strong correlation between oscillatory and translational motion. We show that for sessile drops, the velocity is mainly determined by the amplitude of oscillation and that the saturation observed is due to the nonlinear dependence of the drop response frequency on the dynamically induced stretching.

  19. A novel wireless and temperature-compensated SAW vibration sensor.

    PubMed

    Wang, Wen; Xue, Xufeng; Huang, Yangqing; Liu, Xinlu

    2014-11-03

    A novel wireless and passive surface acoustic wave (SAW) based temperature-compensated vibration sensor utilizing a flexible Y-cut quartz cantilever beam with a relatively substantial proof mass and two one-port resonators is developed. One resonator acts as the sensing device adjacent to the clamped end for maximum strain sensitivity, and the other one is used as the reference located on clamped end for temperature compensation for vibration sensor through the differential approach. Vibration directed to the proof mass flex the cantilever, inducing relative changes in the acoustic propagation characteristics of the SAW travelling along the sensing device, and generated output signal varies in frequency as a function of vibration.  A theoretical mode using the Rayleigh method was established to determine the optimal dimensions of the cantilever beam. Coupling of Modes (COM) model was used to extract the optimal design parameters of the SAW devices prior to fabrication. The performance of the developed SAW sensor attached to an antenna towards applied vibration was evaluated wirelessly by using the precise vibration table, programmable incubator chamber, and reader unit.  High vibration sensitivity of ~10.4 kHz/g, good temperature stability, and excellent linearity were observed in the wireless measurements.

  20. Oblique ion acoustic shock waves in a magnetized plasma

    SciTech Connect

    Shahmansouri, M.; Mamun, A. A.

    2013-08-15

    Ion acoustic (IA) shock waves are studied in a magnetized plasma consisting of a cold viscous ion fluid and Maxwellian electrons. The Korteweg–de Vries–Burgers equation is derived by using the reductive perturbation method. It is shown that the combined effects of external magnetic field and obliqueness significantly modify the basic properties (viz., amplitude, width, speed, etc.) of the IA shock waves. It is observed that the ion-viscosity is a source of dissipation, and is responsible for the formation of IA shock structures. The implications of our results in some space and laboratory plasma situations are discussed.