Science.gov

Sample records for acoustic sensor technology

  1. Gas sensor technology at Sandia National Laboratories: Catalytic gate, Surface Acoustic Wave and Fiber Optic Devices

    SciTech Connect

    Hughes, R.C.; Moreno, D.J.; Jenkins, M.W.; Rodriguez, J.L.

    1993-10-01

    Sandia`s gas sensor program encompasses three separate electronic platforms: Acoustic Wave Devices, Fiber Optic Sensors and sensors based on silicon microelectronic devices. A review of most of these activities was presented recently in a article in Science under the title ``Chemical Microsensors.`` The focus of the program has been on understanding and developing the chemical sensor coatings that are necessary for using these electronic platforms as effective chemical sensors.

  2. Acoustic particle acceleration sensors

    SciTech Connect

    Franklin, J.B.; Barry, P.J.

    1996-04-01

    A crossed dipole array provides a directional receiving capability in a relatively small sensor package and is therefore very attractive for many applications in acoustics. Particle velocity measurements on two axes perpendicular to each other are required to provide the dipole signals. These can be obtained directly using particle velocity sensors or via simple transfer functions using acceleration and displacement sensors. Also, the derivative of the acoustic pressure with respect to space provides a signal proportional to the particle acceleration and gives rise to the pressure gradient sensor. Each of these sensors has strengths and drawbacks depending on the frequency regime of interest, the noise background, and whether a point or a line configuration of dipole sensors is desired. In this paper, the performance of acceleration sensors is addressed using a sensor concept developed at DREA. These sensors exploit bending stresses in a cantilever beam of piezoelectric material to obtain wide bandwidth and high sensitivity. Models which predict the acceleration sensitivity, pressure sensitivity, and natural frequency for this type of sensor are described. Experimental results obtained using several different versions of these sensors are presented and compared with theory. The predicted performance of acceleration sensors are compared with that of pressure gradient arrays and particle velocity sensors. {copyright} {ital 1996 American Institute of Physics.}

  3. The acoustic vector sensor: a versatile battlefield acoustics sensor

    NASA Astrophysics Data System (ADS)

    de Bree, Hans-Elias; Wind, Jelmer W.

    2011-06-01

    The invention of the Microflown sensor has made it possible to measure acoustic particle velocity directly. An acoustic vector sensor (AVS) measures the particle velocity in three directions (the source direction) and the pressure. The sensor is a uniquely versatile battlefield sensor because its size is a few millimeters and it is sensitive to sound from 10Hz to 10kHz. This article shows field tests results of acoustic vector sensors, measuring rifles, heavy artillery, fixed wing aircraft and helicopters. Experimental data shows that the sensor is suitable as a ground sensor, mounted on a vehicle and on a UAV.

  4. In-Flow Acoustic Sensor

    NASA Technical Reports Server (NTRS)

    Allen, Christopher S. (Inventor)

    1995-01-01

    An acoustic sensor for measuring acoustic waves contained in fluid flow flowing over the sensor is introduced. The acoustic sensor reduces any unwanted self-noise associated with the flowing fluid by providing a nose cone having proper aerodynamic properties and by positioning the diaphragm of a microphone of the sensor at a location where any unwanted noise is at a relatively low level. The nose cone has a rounded, blunt or even sharp tip neither of which creates any major disturbances in the flowing fluid which it intercepts.

  5. 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).

  6. Acoustic/Magnetic Stress Sensor

    NASA Technical Reports Server (NTRS)

    Heyman, J. S.; Namkung, M.

    1986-01-01

    High-resolution sensor fast, portable, does not require permanent bonding to structure. Sensor measures nondestructively type (compressive or tensile) and magnitude of stresses and stress gradients present in class of materials. Includes precise high-resolution acoustic interferometer, sending acoustic transducer, receiving acoustic transducer, electromagnet coil and core, power supply, and magnetic-field-measuring device such as Hall probe. This measurement especially important for construction and applications where steel is widely used. Sensor useful especially for nondestructive evaluation of stress in steel members because of portability, rapid testing, and nonpermanent installation.

  7. Acoustic emission sensor radiation damage threshold experiment

    SciTech Connect

    Beeson, K.M.; Pepper, C.E.

    1994-09-01

    Determination of the threshold for damage to acoustic emission sensors exposed to radiation is important in their application to leak detection in radioactive waste transport and storage. Proper response to system leaks is necessary to ensure the safe operation of these systems. A radiation impaired sensor could provide ``false negative or false positive`` indication of acoustic signals from leaks within the system. Research was carried out in the Radiochemical Technology Division at Oak Ridge National Laboratory to determine the beta/gamma radiation damage threshold for acoustic emission sensor systems. The individual system consisted of an acoustic sensor mounted with a two part epoxy onto a stainless steel waveguide. The systems were placed in an irradiation fixture and exposed to a Cobalt-60 source. After each irradiation, the sensors were recalibrated by Physical Acoustics Corporation. The results were compared to the initial calibrations performed prior to irradiation and a control group, not exposed to radiation, was used to validate the results. This experiment determines the radiation damage threshold of each acoustic sensor system and verifies its life expectancy, usefulness and reliability for many applications in radioactive environments.

  8. Sensor technology

    NASA Technical Reports Server (NTRS)

    Sokoloski, Martin M.

    1988-01-01

    The objective is to provide necessary expertise and technology to advance space remote sensing of terrestrial, planetary, and galactic phenomena through the use of electromagnetic and electro-optic properties of gas, liquid, and solid state materials technology. The Sensor Technology Program is divided into two subprograms: a base research and development part and a Civil Space Technology Initiative (CSTI) part. The base research and development consists of research on artificially grown materials such as quantum well and superlattice structure with the potential for new and efficient means for detecting electromagnetic phenomena. Research is also being done on materials and concepts for detector components and devices for measuring high energy phenomena such as UV, X-, and gamma rays that are required observables in astrophysis and solar physics missions. The CSTI program is more mission driven and is balanced among four major disciplines: detector sensors; submillimeter wave sensors; LIDAR/DIAL sensors; and cooler technology.

  9. Deghosting in multipassive acoustic sensors

    NASA Astrophysics Data System (ADS)

    Yang, Rong; Ng, Gee Wah

    2004-04-01

    In this paper, we describe a deghosting algorithm in multiple passive acoustic sensor environment. In a passive acoustic sensor system, a target is detected by its bearing to the sensor, and the target location is obtained from triangulation of bearings on different sensors. However, in multi-passive sensor and multi-target scenario, triangulation is difficult. This is because multi-target triangulation results in a number of ghost targets being generated. In order to remove the triangulating ghosts, the deghosting technique is essential to distinguish the true targets from the ghost targets. We suggest a deghosting algorithm by applying Bayes" theorem and the likelihood function on the acoustic signals. A probability related to acoustic signal on each triangulating point is recursively computed and updated at every time stamp or frame. The triangulating point will be classified as a true target, once its probability exceeds a predefined threshold. Furthermore, acoustic signal has propagation delay. The situation yields the triangulating location biased to the bearing of the nearest sensor. In our algorithm, the propagation delay problem is solved by matching the histories of bearing tracks, and yields the unbiased location that has similar emitting times for the sensors contributing to the triangulation point. The emitting times can be derived from detecting times and propagation delays. Performance result is presented on simulation data.

  10. Acoustic calibration apparatus for calibrating plethysmographic acoustic pressure sensors

    NASA Technical Reports Server (NTRS)

    Zuckerwar, Allan J. (Inventor); Davis, David C. (Inventor)

    1995-01-01

    An apparatus for calibrating an acoustic sensor is described. The apparatus includes a transmission material having an acoustic impedance approximately matching the acoustic impedance of the actual acoustic medium existing when the acoustic sensor is applied in actual in-service conditions. An elastic container holds the transmission material. A first sensor is coupled to the container at a first location on the container and a second sensor coupled to the container at a second location on the container, the second location being different from the first location. A sound producing device is coupled to the container and transmits acoustic signals inside the container.

  11. Acoustic Humidity Sensor

    NASA Technical Reports Server (NTRS)

    Shakkottai, Parthasarathy; Kwack, Eug Y.; Venkateshan, Shakkottai

    1990-01-01

    Industrial humidity sensor measures volume fraction of water in air via its effect on speed of sound. Only portion of sensor exposed to sensed atmosphere is pair of stainless-steel tubes, one containing dry air and other containing moist air. Counters measure intervals between reflected pulses. Sensor rugged enough for use in harsh environments like those used to control drying of paper in paper mills, where most humidity sensors do not survive.

  12. Acoustic sensor networks for woodpecker localization

    NASA Astrophysics Data System (ADS)

    Wang, H.; Chen, C. E.; Ali, A.; Asgari, S.; Hudson, R. E.; Yao, K.; Estrin, D.; Taylor, C.

    2005-08-01

    Sensor network technology can revolutionize the study of animal ecology by providing a means of non-intrusive, simultaneous monitoring of interaction among multiple animals. In this paper, we investigate design, analysis, and testing of acoustic arrays for localizing acorn woodpeckers using their vocalizations. Each acoustic array consists of four microphones arranged in a square. All four audio channels within the same acoustic array are finely synchronized within a few micro seconds. We apply the approximate maximum likelihood (AML) method to synchronized audio channels of each acoustic array for estimating the direction-of-arrival (DOA) of woodpecker vocalizations. The woodpecker location is estimated by applying least square (LS) methods to DOA bearing crossings of multiple acoustic arrays. We have revealed the critical relation between microphone spacing of acoustic arrays and robustness of beamforming of woodpecker vocalizations. Woodpecker localization experiments using robust array element spacing in different types of environments are conducted and compared. Practical issues about calibration of acoustic array orientation are also discussed.

  13. Frustrated total internal reflection acoustic field sensor

    DOEpatents

    Kallman, Jeffrey S.

    2000-01-01

    A frustrated total internal reflection acoustic field sensor which allows the acquisition of the acoustic field over an entire plane, all at once. The sensor finds use in acoustic holography and acoustic diffraction tomography. For example, the sensor may be produced by a transparent plate with transparent support members tall enough to support one or more flexible membranes at an appropriate height for frustrated total internal reflection to occur. An acoustic wave causes the membrane to deflect away from its quiescent position and thus changes the amount of light that tunnels through the gap formed by the support members and into the membrane, and so changes the amount of light reflected by the membrane. The sensor(s) is illuminated by a uniform tight field, and the reflection from the sensor yields acoustic wave amplitude and phase information which can be picked up electronically or otherwise.

  14. Acoustic optic hybrid (AOH) sensor

    PubMed

    Matthews; Arrieta

    2000-09-01

    The ability of laser vibrometers to receive and process acoustic echoes from the water surface above a submerged target is established and evaluated. Sonar echoes from a submerged target are collected from the water surface by a laser vibrometer. Feasibility of this approach to sensing underwater sound is demonstrated. If the acoustic excitation at an otherwise undisturbed water surface is 195 to 168 dB re: 1 microPa, signal-to-noise ratio (SNR), at the vibrometer output, is shown to range from about 46 to 6 dB. Capillary waves and gravity waves at the water surface are expected and shown to have some destructive effect on the process of echo retrieval. A series of experiments to quantify the surface wave effects is described. The wave experiment results are reported. A successful attempt to acquire echoes from a submerged target over a grid of points for further processing into a three-dimensional image is made and described. The data acquisition and beamforming techniques constitute a three-dimensional, acoustic optic, synthetic aperture sonar (SAS). Beamformed images are included. For an aircraft towing acoustic sensors through the water with a mechanical link, this technique holds the promise of increased safety and improved fuel efficiency. PMID:11008811

  15. New Sensors For Flow Velocity And Acoustics

    NASA Technical Reports Server (NTRS)

    Cho, Y. C.

    1991-01-01

    Paper describes two sensor-development programs at Fluid Mechanics Laboratory at NASA Ames Research Center. One program for digital image velocimetry (DIV) sensors, and other program, for advanced acoustic sensors for wind tunnels. DIV measures, in real time, instantaneous velocity fields of time-varying flow or of collection of objects moving with varying velocities. Advanced acoustic sensors for wind tunnels being developed to reduce effects of interference from wind noise, noise from interactions between flows and sensors, flow-induced vibrations of sensors, deflections of accoustic waves by boundary layers induced by sensors, and reflections from walls and sensor supports.

  16. Acoustic Particle Velocity Sensors: Design, Performance, and Applications Proceedings

    SciTech Connect

    Berliner, M.J.; Lindberg, J.F.

    1996-07-01

    These proceedings represent the papers presented at a workshop sponsored by the Office of Naval Research and the Acoustical Society of America. The topics discussed include designs, applications and performance of underwater acoustic sensors. There were 29 papers presented and all have been abstracted for the Energy Science and Technology database.(AIP)

  17. 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).

  18. Acoustic pressure-vector sensor array

    NASA Astrophysics Data System (ADS)

    Huang, Dehua; Elswick, Roy C.; McEachern, James F.

    2001-05-01

    Pressure-vector sensors measure both scalar and vector components of the acoustic field. December 2003 measurements at the NUWC Seneca Lake test facility verify previous observations that acoustic ambient noise spectrum levels measured by acoustic intensity sensors are reduced relative to either acoustic pressure or acoustic vector sensor spectrum levels. The Seneca measurements indicate a reduction by as much as 15 dB at the upper measurement frequency of 2500 Hz. A nonlinear array synthesis theory for pressure-vector sensors will be introduced that allows smaller apertures to achieve narrow beams. The significantly reduced ambient noise of individual pressure-vector elements observed in the ocean by others, and now at Seneca Lake, should allow a nonlinearly combined array to detect significantly lower levels than has been observed in previous multiplicative processing of pressure sensors alone. Nonlinear array synthesis of pressure-vector sensors differs from conventional super-directive algorithms that linearly combine pressure elements with positive and negative weights, thereby reducing the sensitivity of conventional super-directive arrays. The much smaller aperture of acoustic pressure-vector sensor arrays will be attractive for acoustic systems on underwater vehicles, as well as for other applications that require narrow beam acoustic receivers. [The authors gratefully acknowledge the support of ONR and NUWC.

  19. Improved Calibration Of Acoustic Plethysmographic Sensors

    NASA Technical Reports Server (NTRS)

    Zuckerwar, Allan J.; Davis, David C.

    1993-01-01

    Improved method of calibration of acoustic plethysmographic sensors involves acoustic-impedance test conditions like those encountered in use. Clamped aluminum tube holds source of sound (hydrophone) inside balloon. Test and reference sensors attached to outside of balloon. Sensors used to measure blood flow, blood pressure, heart rate, breathing sounds, and other vital signs from surfaces of human bodies. Attached to torsos or limbs by straps or adhesives.

  20. Acoustic sensor array extracts physiology during movement

    NASA Astrophysics Data System (ADS)

    Scanlon, Michael V.

    2001-08-01

    An acoustic sensor attached to a person's neck can extract heart and breath sounds, as well as voice and other physiology related to their health and performance. Soldiers, firefighters, law enforcement, and rescue personnel, as well as people at home or in health care facilities, can benefit form being remotely monitored. ARLs acoustic sensor, when worn around a person's neck, picks up the carotid artery and breath sounds very well by matching the sensor's acoustic impedance to that of the body via a gel pad, while airborne noise is minimized by an impedance mismatch. Although the physiological sounds have high SNR, the acoustic sensor also responds to motion-induced artifacts that obscure the meaningful physiology. To exacerbate signal extraction, these interfering signals are usually covariant with the heart sounds, in that as a person walks faster the heart tends to beat faster, and motion noises tend to contain low frequency component similar to the heart sounds. A noise-canceling configuration developed by ARL uses two acoustic sensor on the front sides of the neck as physiology sensors, and two additional acoustic sensor on the back sides of the neck as noise references. Breath and heart sounds, which occur with near symmetry and simultaneously at the two front sensor, will correlate well. The motion noise present on all four sensor will be used to cancel the noise on the two physiology sensors. This report will compare heart rate variability derived from both the acoustic array and from ECG data taken simultaneously on a treadmill test. Acoustically derived breath rate and volume approximations will be introduced as well. A miniature 3- axis accelerometer on the same neckband provides additional noise references to validate footfall and motion activity.

  1. Improvement of optical and acoustical technologies for the protection: Project IMOTEP: Network of heterogeneous sensor types for the protection of camps or mobile troops

    NASA Astrophysics Data System (ADS)

    Hengy, Sébastien; Laurenzis, Martin; Zimpfer, Véronique; Schneider, Armin

    2014-10-01

    Snipers have emerged as a major threat to troops in recent conflicts. To reduce this menace, the objective of the French- German Research Institute of Saint Louis (ISL) research project "IMOTEP" is to improve the detection of snipers on the battlefield. Our basic approach is to combine several sources of information for a fast and appropriate reaction when an unusual signal (e.g. a flash or a shot) is detected. The project includes several technologies developed at ISL: acoustical detection, fusion of distributed sensor network data, active imaging and 3D audio communication. The protection of camps, convoys or dismounted soldiers rests on a distributed acoustical sensor network that detects and localizes sniper attacks. An early estimation of the threat position is transmitted through a network to an active imaging system in order to confirm and refine this position by 3D imaging. The refined position is then sent to the control center which generates an alert message that displays the threat position using two formats: a tactical map and a 3D audio signal. In addition, the camp is protected by an ad-hoc sensor network used for intruder detection.

  2. 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

  3. Acoustic sensors using microstructures tunable with energy other than acoustic energy

    DOEpatents

    Datskos, Panagiotis G.

    2005-06-07

    A sensor for detecting acoustic energy includes a microstructure tuned to a predetermined acoustic frequency and a device for detecting movement of the microstructure. A display device is operatively linked to the movement detecting device. When acoustic energy strikes the acoustic sensor, acoustic energy having a predetermined frequency moves the microstructure, where the movement is detected by the movement detecting device.

  4. Acoustic sensors using microstructures tunable with energy other than acoustic energy

    DOEpatents

    Datskos, Panagiotis G.

    2003-11-25

    A sensor for detecting acoustic energy includes a microstructure tuned to a predetermined acoustic frequency and a device for detecting movement of the microstructure. A display device is operatively linked to the movement detecting device. When acoustic energy strikes the acoustic sensor, acoustic energy having a predetermined frequency moves the microstructure, where the movement is detected by the movement detecting device.

  5. Digital Sensor Technology

    SciTech Connect

    Ted Quinn; Jerry Mauck; Richard Bockhorst; Ken Thomas

    2013-07-01

    The nuclear industry has been slow to incorporate digital sensor technology into nuclear plant designs due to concerns with digital qualification issues. However, the benefits of digital sensor technology for nuclear plant instrumentation are substantial in terms of accuracy, reliability, availability, and maintainability. This report demonstrates these benefits in direct comparisons of digital and analog sensor applications. It also addresses the qualification issues that must be addressed in the application of digital sensor technology.

  6. Issues in acoustic vector-sensor processing

    NASA Astrophysics Data System (ADS)

    Hawkes, Malcolm Alistair

    This dissertation examines the ability of acoustic vector sensors to solve the passive direction-of-arrival (DOA) estimation and 3-D localization problems. These sensors measure the three-dimensional acoustic particle velocity vector, as well as the acoustic pressure, at one location. By preserving directional information that is present in the structure of the velocity field, they gain a number of advantages over traditional arrays of scalar sensors, such as hydrophones and microphones. We compute and examine, through the Cramér-Rao bound and beam-forming based methods, the ability of arrays of acoustic vector sensors to estimate direction. We first consider the case of an array in free space then extend these results to account for the presence of a reflecting boundary, such as the seabed or a vessel's hull, located near the array. Next, we derive expressions for the noise correlation structure induced by various ambient noise fields, isotropic and anisotropic, at an acoustic vector sensor array, and use them to examine its localization performance. We then propose a decentralized processing scheme to rapidly locate a wideband target in three dimensions. Finally, we present a general framework for the analysis of errors associated with the estimation of a vector, or system of vectors, that has geometrical interpretations in terms of length, angle, etc. The framework is employed throughout the thesis.

  7. Vector Sensor Arrays in Underwater Acoustic Applications

    NASA Astrophysics Data System (ADS)

    Santos, Paulo; Felisberto, Paulo; Jesus, Sérgio M.

    Traditionally, ocean acoustic signals have been acquired using hydrophones, which measure the pressure field and are typically omnidirectional. A vector sensor measures both the acoustic pressure and the three components of particle velocity. Assembled into an array, a vector sensor array (VSA) improves spatial filtering capabilities when compared with arrays of same length and same number of hydrophones. The objective of this work is to show the advantage of the use of vector sensors in underwater acoustic applications such as direction of arrival (DOA) estimation and geoacoustic inversion. Beyond the improvements in DOA estimation, it will be shown the advantages of using the VSA in bottom parameters estimation. Additionally, is tested the possibility of using high frequency signals (say 8-14 kHz band), acquired during the MakaiEx 2005, to allow a small aperture array, reducing the cost of actual sub-bottom profilers and providing a compact and easy-to-deploy system.

  8. Acoustic mapping of ocean currents using networked distributed sensors.

    PubMed

    Huang, Chen-Fen; Yang, T C; Liu, Jin-Yuan; Schindall, Jeff

    2013-09-01

    Distributed underwater sensors are expected to provide oceanographic monitoring over large areas. As fabrication technology advances, low cost sensors will be available for many uses. The sensors communicate to each other and are networked using acoustic communications. This paper first studies the performance of such systems for current measurements using tomographic inversion approaches to compare with that of a conventional system which distributes the sensors on the periphery of the area of interest. It then proposes two simple signal processing methods for ocean current mapping (using distributed networked sensors) aimed at real-time in-buoy processing. Tomographic inversion generally requires solving a challenging high dimensional inverse problem, involving substantial computations. Given distributed sensors, currents can be constructed locally based on data from neighboring sensors. It is shown using simulated data that similar results are obtained using distributed processing as using conventional tomographic approaches. The advantage for distributed systems is that by increasing the number of nodes, one gains a much more improved performance. Furthermore, distributed systems use much less energy than a conventional tomographic system for the same area coverage. Experimental data from an acoustic communication and networking experiment are used to demonstrate the feasibility of acoustic current mapping. PMID:23967940

  9. Multipurpose Acoustic Sensor for Downhole Fluid Monitoring

    SciTech Connect

    Pantea, Cristian

    2012-05-04

    The projects objectives and purpose are to: (1) development a multipurpose acoustic sensor for downhole fluid monitoring in Enhanced Geothermal Systems (EGS) reservoirs over typical ranges of pressures and temperatures and demonstrate its capabilities and performance for different EGS systems; (2) determine in real-time and in a single sensor package several parameters - temperature, pressure, fluid flow and fluid properties; (3) needed in nearly every phase of an EGS project, including Testing of Injection and Production Wells, Reservoir Validation, Inter-well Connectivity, Reservoir Scale Up and Reservoir Sustainability. (4) Current sensors are limited to operating at lower temperatures, but the need is for logging at high temperatures. The present project deals with the development of a novel acoustic-based sensor that can work at temperatures up to 374 C, in inhospitable environments.

  10. Acoustic composition sensor for cryogenic gas mixtures

    NASA Technical Reports Server (NTRS)

    Shakkottai, P.; Kwack, E. Y.; Luchik, T. S.; Back, L. H.

    1991-01-01

    An acoustic sensor useful for the determination of the composition of a gaseous binary mixture in cryogenic liquid spills has been characterized. One version of the instrument traps a known mixture of helium and nitrogen at ambient temperature in a tube which is interrogated by sonic pulses to determine the speed of sound and hence the composition. Experimental data shows that this sensor is quite accurate. The second version uses two unconfined microphones which sense sound pulses. Experimental data acquired during mixing when liquid nitrogen is poured into a vessel of gaseous helium is presented. Data during transient cooling of the tubular sensor containing nitrogen when the sensor is dipped into liquid nitrogen and during transient warm-up when the sensor is withdrawn are also presented. This sensor is being developed for use in the mixing of liquid cryogens with gas evolution in the simulation of liquid hydrogen/liquid oxygen explosion hazards.

  11. Vector Acoustic Sensors for Marine Seismic Surveys

    NASA Astrophysics Data System (ADS)

    Lindwall, D.

    2005-12-01

    Using vector acoustic sensors for marine seismic and geo-acoustic surveys instead of the usual scalar hydrophones allows for acquiring a 3-D survey with the instrumentation and logistics similar to current 2-D surveys. Vector acoustic sensors measure the wave direction directly without the large and cumbersome arrays that hydrophones require. This concept was tested by a scaled experiment in an acoustic water tank that has a well controlled environment with a few targets. The experiment was scaled to the size of the available water tank and the frequency limits of the sensor. The sensor consists of a three-axis accelerometer as well as a hydrophone. The sound source was a standard hydrophone driven by a short 8 kHz pulse. The sensor was suspended in a fixed location and the hydrophone was moved about the tank by a robotic arm to insonify the tank from many locations. During part of the experiment, several floats (acoustic targets) were placed in the tank at diagonal ranges of approximately one meter. The accelerometer data show the direct source wave as well as the target scattered waves and reflections from the nearby water surface, tank bottom and sides. Vector data from single shots show that the wave motion direction can be readily determined for both direct waves and scattered waves. Without resorting to the usual methods of seismic imaging, which in this case would have only been two dimensional and relied entirely on the use of a synthetic source aperture, the three-dimensional volume of the tank environment was imaged. This work was supported by the Office of Naval Research, program element 61153N.

  12. 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.

  13. Advanced sensors technology survey

    NASA Technical Reports Server (NTRS)

    Cooper, Tommy G.; Costello, David J.; Davis, Jerry G.; Horst, Richard L.; Lessard, Charles S.; Peel, H. Herbert; Tolliver, Robert

    1992-01-01

    This project assesses the state-of-the-art in advanced or 'smart' sensors technology for NASA Life Sciences research applications with an emphasis on those sensors with potential applications on the space station freedom (SSF). The objectives are: (1) to conduct literature reviews on relevant advanced sensor technology; (2) to interview various scientists and engineers in industry, academia, and government who are knowledgeable on this topic; (3) to provide viewpoints and opinions regarding the potential applications of this technology on the SSF; and (4) to provide summary charts of relevant technologies and centers where these technologies are being developed.

  14. Longitudinal bulk acoustic mass sensor

    SciTech Connect

    Hales, J. H.; Teva, J.; Boisen, A.; Davis, Z. J.

    2009-07-20

    A polycrystalline silicon longitudinal bulk acoustic cantilever is fabricated and operated in air at 51 MHz. A mass sensitivity of 100 Hz/fg (1 fg=10{sup -15} g) is obtained from the preliminary experiments where a minute mass is deposited on the device by means of focused ion beam. The total noise in the currently applied measurement system allows for a minimum detectable mass of 0.5 fg in air.

  15. Development of an accelerometer-based underwater acoustic intensity sensor

    NASA Astrophysics Data System (ADS)

    Kim, Kang; Gabrielson, Thomas B.; Lauchle, Gerald C.

    2004-12-01

    An underwater acoustic intensity sensor is described. This sensor derives acoustic intensity from simultaneous, co-located measurement of the acoustic pressure and one component of the acoustic particle acceleration vector. The sensor consists of a pressure transducer in the form of a hollow piezoceramic cylinder and a pair of miniature accelerometers mounted inside the cylinder. Since this sensor derives acoustic intensity from measurement of acoustic pressure and acoustic particle acceleration, it is called a p-a intensity probe. The sensor is ballasted to be nearly neutrally buoyant. It is desirable for the accelerometers to measure only the rigid body motion of the assembled probe and for the effective centers of the pressure sensor and accelerometer to be coincident. This is achieved by symmetric disposition of a pair of accelerometers inside the ceramic cylinder. The response of the intensity probe is determined by comparison with a reference hydrophone in a predominantly reactive acoustic field. .

  16. Surface Acoustic Wave (SAW) Vibration Sensors

    PubMed Central

    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. PMID:22247694

  17. 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. PMID:22247694

  18. Digital Sensor Technology

    SciTech Connect

    Thomas, Ken D.; Quinn, Edward L.; Mauck, Jerry L.; Bockhorst, Richard M.

    2015-02-01

    The nuclear industry has been slow to incorporate digital sensor technology into nuclear plant designs due to concerns with digital qualification issues. However, the benefits of digital sensor technology for nuclear plant instrumentation are substantial in terms of accuracy and reliability. This paper, which refers to a final report issued in 2013, demonstrates these benefits in direct comparisons of digital and analog sensor applications. Improved accuracy results from the superior operating characteristics of digital sensors. These include improvements in sensor accuracy and drift and other related parameters which reduce total loop uncertainty and thereby increase safety and operating margins. An example instrument loop uncertainty calculation for a pressure sensor application is presented to illustrate these improvements. This is a side-by-side comparison of the instrument loop uncertainty for both an analog and a digital sensor in the same pressure measurement application. Similarly, improved sensor reliability is illustrated with a sample calculation for determining the probability of failure on demand, an industry standard reliability measure. This looks at equivalent analog and digital temperature sensors to draw the comparison. The results confirm substantial reliability improvement with the digital sensor, due in large part to ability to continuously monitor the health of a digital sensor such that problems can be immediately identified and corrected. This greatly reduces the likelihood of a latent failure condition of the sensor at the time of a design basis event. Notwithstanding the benefits of digital sensors, there are certain qualification issues that are inherent with digital technology and these are described in the report. One major qualification impediment for digital sensor implementation is software common cause failure (SCCF).

  19. New Sensor Technology

    NASA Technical Reports Server (NTRS)

    Covault, Craig

    2005-01-01

    The three instruments on the Orbiter Boom Sensor System (OBSS) will use a mix of U.S. and Canadian developed laser, television, infrared, and 3D imaging technologies. The sensors are the: 1) Laser Dynamic Range Imager (LDRI); 2) Intensified Television Camera (ITVC); 3) Laser Camera System (LCS).

  20. An oxygen pressure sensor using surface acoustic wave devices

    NASA Technical Reports Server (NTRS)

    Leighty, Bradley D.; Upchurch, Billy T.; Oglesby, Donald M.

    1993-01-01

    Surface acoustic wave (SAW) piezoelectric devices are finding widespread applications in many arenas, particularly in the area of chemical sensing. We have developed an oxygen pressure sensor based on coating a SAW device with an oxygen binding agent which can be tailored to provide variable sensitivity. The coating is prepared by dissolving an oxygen binding agent in a toluene solution of a copolymer which is then sprayed onto the surface of the SAW device. Experimental data shows the feasibility of tailoring sensors to measure the partial pressure of oxygen from 2.6 to 67 KPa (20 to 500 torr). Potential applications of this technology are discussed.

  1. Acoustic Separation Technology

    SciTech Connect

    Fred Ahrens; Tim Patterson

    2002-02-22

    Today's restrictive environmental regulations encourage paper mills to close their water systems. Closed water systems increase the level of contaminants significantly. Accumulations of solid suspensions are detrimental to both the papermaking process and the final products. To remove these solids, technologies such as flotation using dissolved air (DAF), centrifuging, and screening have been developed. Dissolved Air Flotation systems are commonly used to clarify whitewater. These passive systems use high pressure to dissolve air into whitewater. When the pressure is released, air micro-bubbles form and attach themselves to fibers and particles, which then float to the surface where they are mechanically skimmed off. There is an economic incentive to explore alternatives to the DAF technology to drive down the cost of whitewater processing and minimize the use of chemicals. The installed capital cost for a DAF system is significant and a typical DAF system takes up considerable space. An alternative approach, which is the subject of this project, involves a dual method combining the advantages of chemical flocculation and in-line ultrasonic clarification to efficiently remove flocculated contaminants from a water stream

  2. Electron tunnel sensor technology

    NASA Technical Reports Server (NTRS)

    Waltman, S. B.; Kaiser, W. J.

    1989-01-01

    The recent development of Scanning Tunneling Microscopy technology allows the application of electron tunneling to position detectors for the first time. The vacuum tunnel junction is one of the most sensitive position detection mechanisms available. It is also compact, simple, and requires little power. A prototype accelerometer based on electron tunneling, and other sensor applications of this promising new technology are described.

  3. Investigation of acoustic sensors to detect coconut rhinoceros beetle in Guam

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The coconut rhinoceros beetle, Oryctes rhinoceros, was accidentally introduced into Guam last year and now threatens the Island’s forests and tourist industry. These large insects can be detected easily with acoustic sensors, and procedures are being developed to incorporate acoustic technology int...

  4. Acoustic and Seismic Modalities for Unattended Ground Sensors

    SciTech Connect

    Elbring, G.J.; Ladd, M.D.; McDonald, T.S.; Sleefe, G.E.

    1999-03-31

    In this paper, we have presented the relative advantages and complementary aspects of acoustic and seismic ground sensors. A detailed description of both acoustic and seismic ground sensing methods has been provided. Acoustic and seismic phenomenology including source mechanisms, propagation paths, attenuation, and sensing have been discussed in detail. The effects of seismo-acoustic and acousto-seismic interactions as well as recommendations for minimizing seismic/acoustic cross talk have been highlighted. We have shown representative acoustic and seismic ground sensor data to illustrate the advantages and complementary aspects of the two modalities. The data illustrate that seismic transducers often respond to acoustic excitation through acousto-seismic coupling. Based on these results, we discussed the implications of this phenomenology on the detection, identification, and localization objectives of unattended ground sensors. We have concluded with a methodology for selecting the preferred modality (acoustic and/or seismic) for a particular application.

  5. Cooperative implementation of a high temperature acoustic sensor

    NASA Astrophysics Data System (ADS)

    Baldini, S. E.; Nowakowski, Edward; Smith, Herbert G.; Friebele, E. J.; Putnam, Martin A.; Rogowski, Robert; Melvin, Leland D.; Claus, Richard O.; Tran, Tuan; Holben, Milford S., Jr.

    1991-12-01

    The current status and results of a cooperative program aimed at the implementation of a high-temperature acoustic/strain sensor onto metallic structures are reported. The sensor systems that are to be implemented under this program will measure thermal expansion, maneuver loads, aircraft buffet, sonic fatigue, and acoustic emissions in environments that approach 1800 F. The discussion covers fiber development, fabrication of an extrinsic Fabry-Perot interferometer acoustic sensor, sensor mounting/integration, and results of an evaluation of the sensor capabilities.

  6. Investigation of the thickness effect to impedance analysis results AlGaN acoustic sensor

    NASA Astrophysics Data System (ADS)

    Özen, Soner; Bilgiç, Eyüp; Gülmez, Gülay; Şenay, Volkan; Pat, Suat; Korkmaz, Şadan; Mohammadigharehbagh, Reza

    2016-03-01

    In this study, AlGaN acoustic sensors were deposited on aluminum metal substrate by thermionic vacuum arc (TVA) method, for the first time. Impedance analyses of the fabricated acoustic sensors were investigated for the determining of effect of the nano layer thickness. Thickness values are very close to each others. Fabricated sensors have been fabricated from AlGaN deposited on aluminum substrates. Gallium materials are used in many applications for optoelectronic device and semiconductor technology. Thermionic vacuum arc is the deposition technology for the variously materials and applications field. TVA production parameters and some properties of the deposited layers were investigated. TVA is the fast deposition technology for the gallium compounds and doped gallium compounds. Obtained results that AlGaN layer are very promising material for an acoustic sensor but also TVA is proper fast technology for the production.

  7. Measuring aeolian sand transport using acoustic sensors

    NASA Astrophysics Data System (ADS)

    Poortinga, Ate; van Rheenen, Hans; Ellis, Jean T.; Sherman, Douglas J.

    2015-03-01

    Acoustic sensors are frequently used to measure aeolian saltation. Different approaches are used to process the signals from these instruments. The goal of this paper is to describe and discuss a method to measure aeolian saltation with acoustic sensors. In a laboratory experiment, we measured the output from an advanced signal processing scheme on the circuit board of the saltiphone. We use a software implementation of this processing scheme to re-analyse data from four miniphones obtained during a field experiment. It is shown that a set of filters remove background noise outside the frequency spectrum of aeolian saltation (at 8 kHz), whereas signals within this frequency spectrum are amplified. The resulting analogue signal is a proxy of the energy. Using an AC pulse convertor, this signal can be converted into a digital and analogue count signal or an analogue energy signal, using a rectifier and integrator. Spatio-temporal correlation between field deployed miniphones increases by using longer integration times for signal processing. To quantify aeolian grain impact, it is suggested to use the analogue energy output, as this mode is able to detect changes in frequency and amplitude. The analogue and digital count signals are able to detect an increase in frequency, but are not able to detect an increase in signal amplitude. We propose a two-stage calibration scheme consisting of (1) a factory calibration, to set the frequency spectrum of the sensor and (2) a standardized drop-test conducted before and after the experiment to evaluate the response of the sensor.

  8. 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.

  9. Bio-Inspired Micromechanical Directional Acoustic Sensor

    NASA Astrophysics Data System (ADS)

    Swan, William; Alves, Fabio; Karunasiri, Gamani

    Conventional directional sound sensors employ an array of spatially separated microphones and the direction is determined using arrival times and amplitudes. In nature, insects such as the Ormia ochracea fly can determine the direction of sound using a hearing organ much smaller than the wavelength of sound it detects. The fly's eardrums are mechanically coupled, only separated by about 1 mm, and have remarkable directional sensitivity. A micromechanical sensor based on the fly's hearing system was designed and fabricated on a silicon on insulator (SOI) substrate using MEMS technology. The sensor consists of two 1 mm2 wings connected using a bridge and to the substrate using two torsional legs. The dimensions of the sensor and material stiffness determine the frequency response of the sensor. The vibration of the wings in response to incident sound at the bending resonance was measured using a laser vibrometer and found to be about 1 μm/Pa. The electronic response of the sensor to sound was measured using integrated comb finger capacitors and found to be about 25 V/Pa. The fabricated sensors showed good directional sensitivity. In this talk, the design, fabrication and characteristics of the directional sound sensor will be described. Supported by ONR and TDSI.

  10. Sensor localization using helicopter acoustic and GPS data

    NASA Astrophysics Data System (ADS)

    Damarla, Thyagaraju R.; Mirelli, Vincent

    2004-09-01

    In this paper we present an algorithm to determine the location of an acoustic sensor array using the direction of arrival (DOA) estimates of a moving acoustic source whose ground truth is available. Determination of location and orientation of sensor array based on the statistics of errors in the DOA estimation is a nonlinear regression problem. We formulate and derive the necessary equations to solve this problem in terms of the bearing estimates of the acoustic source and its location. The algorithm is tested against helicopter data from three acoustic sensor arrays distributed over a field.

  11. Low-cost acoustic sensors for littoral anti-submarine warfare (ASW)

    NASA Astrophysics Data System (ADS)

    Towle, Jonathan P.; Herold, David; Johnson, Ryan; Vincent, Harold

    2007-04-01

    Detecting modern diesel-electric submarines operating on batteries in littoral waters is very difficult using traditional sonar technology due in large part to the noisy and reverberant acoustic environment. To address this issue, SI2 Technologies Inc. (SI2) has developed a small, low cost, short range, dual mode acoustic sensor. The sensors can be deployed in large numbers (hundreds or thousands) to provide a high density sensor field depending upon the application of interest. SI2's low cost sensors have a short detection range and therefore are far less susceptible to multi-path reverberations and other acoustic artifacts. Simulation results will be presented showing that high probabilities of detection (P D) can be achieved with low false alarm rates (FAR) using a field of a few hundred of these low cost sensors.

  12. Robotic vehicle uses acoustic sensors for voice detection and diagnostics

    NASA Astrophysics Data System (ADS)

    Young, Stuart H.; Scanlon, Michael V.

    2000-07-01

    An acoustic sensor array that cues an imaging system on a small tele- operated robotic vehicle was used to detect human voice and activity inside a building. The advantage of acoustic sensors is that it is a non-line of sight (NLOS) sensing technology that can augment traditional LOS sensors such as visible and IR cameras. Acoustic energy emitted from a target, such as from a person, weapon, or radio, will travel through walls and smoke, around corners, and down corridors, whereas these obstructions would cripple an imaging detection system. The hardware developed and tested used an array of eight microphones to detect the loudest direction and automatically setter a camera's pan/tilt toward the noise centroid. This type of system has applicability for counter sniper applications, building clearing, and search/rescue. Data presented will be time-frequency representations showing voice detected within rooms and down hallways at various ranges. Another benefit of acoustics is that it provides the tele-operator some situational awareness clues via low-bandwidth transmission of raw audio data for the operator to interpret with either headphones or through time-frequency analysis. This data can be useful to recognize familiar sounds that might indicate the presence of personnel, such as talking, equipment, movement noise, etc. The same array also detects the sounds of the robot it is mounted on, and can be useful for engine diagnostics and trouble shooting, or for self-noise emanations for stealthy travel. Data presented will characterize vehicle self noise over various surfaces such as tiles, carpets, pavement, sidewalk, and grass. Vehicle diagnostic sounds will indicate a slipping clutch and repeated unexpected application of emergency braking mechanism.

  13. Acoustic velocity sensor for the NRL ABC research platform

    SciTech Connect

    Corsaro, R.D.; Houston, B.

    1996-04-01

    A new research platform has been constructed for general underwater structural-acoustics studies of sensor/actuator coupling mechanisms, and in particular for active acoustic boundary control (ABC) studies. It consists of an array of 15 {open_quote}{open_quote}ABC{close_quote}{close_quote} tiles arranged in a 5{times}3 pattern on a backing structure (an air-backed steel plate). Tiles are 10 inches square, and each tile contains a large area actuator, pressure sensor, and (acoustic particle) velocity sensor. While the actuator and pressure sensor could be constructed of commercially available transducer material, the selection of a suitable acoustic velocity sensor proved more difficult. This paper describes the velocity sensor system selected and its impact on the resulting performance and characteristics of the ABC Platform. {copyright} {ital 1996 American Institute of Physics.}

  14. 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.

  15. Distributed fiber optic acoustic sensor for leak detection

    NASA Astrophysics Data System (ADS)

    Kurmer, John P.; Kingsley, Stuart A.; Laudo, John S.; Krak, Stephen J.

    1992-01-01

    Leaks in dielectric fluid-filled, high-voltage distribution lines can cause significant problems for the electric power industry. Often, these lines run over long distance and are difficult to access. Operators may know that a leak exists because additional fluid is required to maintain pipe pressure; however, locating the leak is often a significant challenge. A system that could monitor and locate leaks within the electrical distribution pipe lines would be highly desirable. We present a distributed fiber optic acoustic sensor technology that could be used to measure and locate leaks within fluid-filled, high-voltage distribution lines. In this application, the optical fiber sensor is placed inside the fluid-filled pipe and can potentially locate leaks to within several meters. The fiber optic acoustic sensor is designed such that it can listen to the sound produced by the fluid as it escapes from the pipe into the surrounding soil. The fluid inside the pipe is typically maintained at a pressure of 200 psi and escapes at high velocity when a leak occurs. The distributed fiber optic sensing system being developed is based upon the Sagnac interferometer and is unusual in that range information is not obtained by the more common method of optical time domain reflectometry or optical frequency domain reflectometry, but by essentially a CW technique which works in the frequency domain. It is also unusual in that the signal processing technique actually looks for the absence of a signal.

  16. Electro-acoustic sensors based on AlN thin film: possibilities and limitations

    NASA Astrophysics Data System (ADS)

    Wingqvist, Gunilla

    2011-06-01

    The non-ferroelectric polar wurtzite aluminium nitride (AlN) material has been shown to have potential for various sensor applications both utilizing the piezoelectric effect directly for pressure sensors or indirectly for acoustic sensing of various physical, chemical and biochemical sensor applications. Especially, sputter deposited AlN thin films have played a central role for successful development of the thin film electro-acoustic technology. The development has been primarily driven by one device - the thin film bulk acoustic resonator (FBAR or TFBAR), with its primary use for high frequency filter applications for the telecom industry. AlN has been the dominating choice for commercial application due to compatibility with the integrated circuit technology, low acoustic and dielectric losses, high acoustic velocity in combination with comparably high (but still for some applications limited) electromechanical coupling. Recently, increased piezoelectric properties (and also electromechanical coupling) in the AlN through the alloying with scandium nitride (ScN) have been identified both experimentally and theoretically. Inhere, the utilization of piezoelectricity in electro-acoustic sensing will be discussed together with expectation on acoustic FBAR sensor performance with variation in piezoelectric material properties in the parameter space around AlN due to alloying, in view of the ScxAl1-xN (0

  17. Mobile Sensor Technologies Being Developed

    NASA Technical Reports Server (NTRS)

    Greer, Lawrence C.; Oberle, Lawrence G.

    2003-01-01

    The NASA Glenn Research Center is developing small mobile platforms for sensor placement, as well as methods for communicating between roving platforms and a central command location. The first part of this project is to use commercially available equipment to miniaturize an existing sensor platform. We developed a five-circuit-board suite, with an average board size of 1.5 by 3 cm. Shown in the preceding photograph, this suite provides all motor control, direction finding, and communications capabilities for a 27- by 21- by 40-mm prototype mobile platform. The second part of the project is to provide communications between mobile platforms, and also between multiple platforms and a central command location. This is accomplished with a low-power network labeled "SPAN," Sensor Platform Area Network, a local area network made up of proximity elements. In practice, these proximity elements are composed of fixed- and mobile-sensor-laden science packages that communicate to each other via radiofrequency links. Data in the network will be shared by a central command location that will pass information into and out of the network through its access to a backbone element. The result will be a protocol portable to general purpose microcontrollers satisfying a host of sensor networking tasks. This network will enter the gap somewhere between television remotes and Bluetooth but, unlike 802.15.4, will not specify a physical layer, thus allowing for many data rates over optical, acoustical, radiofrequency, hardwire, or other media. Since the protocol will exist as portable C-code, developers may be able to embed it in a host of microcontrollers from commercial to space grade and, of course, to design it into ASICs. Unlike in 802.15.4, the nodes will relate to each other as peers. A demonstration of this protocol using the two test bed platforms was recently held. Two NASA modified, commercially available, mobile platforms communicated and shared data with each other and a

  18. Vertically integrated sensor array technology for unattended sensor networks (Keynote Address)

    NASA Astrophysics Data System (ADS)

    Balcerak, Raymond; Thurston, John; Breedlove, Jonathan

    2005-05-01

    The increasing need for unattended sensor networks drives individual sensor development, signal processing for network management, and communication technology. The application space is becoming more complex, with requirements for sensor networks in force protection; surveillance of large expanses of rugged terrain; and monitoring complex urban areas. Individual sensors exhibit excellent performance and include a wide variety of sensing modes, such as acoustic, electro-optical imaging, seismic, and radio frequency devices. These sensors continue to shrink with packaging, while applications continue to demand more of the sensor technology. Although single imaging arrays, which are available in spectral bands from the visible through the infrared, can be integrated into packages size as small as a cubic inch, the information from a single sensor is not sufficient to meet requirements for day/night, all-weather operation. This has driven the need for integration of multiple sensors into the compact packages intended for an individual sensor. A major step toward addressing the need for more effective sensor technology for unattended sensor networks is being taken through development of Vertically Integrated Sensor Array (VISA) technology. This technology, currently being developed for imaging sensors, builds multiple layers of signal processing at each pixel in the sensor array. Processing power is dramatically increased, allowing the integration of multiple sensors in small compact packages. This paper reviews the VISA approach to imaging sensors and describes applications for unattended sensors.

  19. Fiber Sensor Technology Today

    NASA Astrophysics Data System (ADS)

    Hotate, Kazuo

    2006-08-01

    Fiber sensor technologies are overviewed. Since the early 1970s, this field has been developed, on the basis of the same devices and photonic principles as fiber communication technologies. Besides simple configurations, in which the fiber acts only as a data transmission line, sophisticated configurations have also been developed, in which the fiber is used as a device to realize unique sensing mechanisms. The fiber optic gyroscope (FOG) is a good example, and has been developed as an absolute rotation sensor used, for example, for navigation and/or attitude control applications. Compared with traditional spinning-mass gyroscopes, the FOG has advantages, such as a short warming-up time, a light weight, and easy handling. A Japanese satellite, which was launched in August 2005 with a mission to observe the aurora, is controlled with a FOG. The FOG has also been used in consumer applications, such as the camera stabilizer, radio-controlled (RC) helicopter navigation, and the control of humanoid robots. Recently, distributed and multiplexed sensing schemes, in particular, have been studied and developed, in which a long fiber acts like a “nerve” for feeling the strain and/or the temperature distribution along the fiber. Performances of artificial nerve systems have markedly improved within the last couple of years, in spatial resolution and measurement speed. By embedding the “fiber-optic nerve system” in aircraft wings, bridges and tall buildings, these materials and structures can sense damage to prevent disasters.

  20. Wide-band polarization-insensitive fiber optic acoustic sensors

    NASA Astrophysics Data System (ADS)

    Shih, Sung-Tsun

    1998-03-01

    A polarization-insensitive fiber optic acoustic sensor is constructed with a 3 X 3 coupler and Faraday rotator mirrors. This system deals with the polarization-induced signal fading by a passive method. The method is eliminating polarization-induced signal fading and the output intensities of this system are described and demonstrated. The homodyne symmetric demodulation system used to recover the sensing signal is also analyzed in detail with experimental verification. The sensing head of this sensor is made of single mode optical fiber wound in to a cylindrical shell with cast polyurethane rubber as the acoustic window. The sensitivity of this sensor is measured in anechoic water tank. The results show that this senor has a stable receiving sensitivity of - 145.5 dB re 1V/(mu) Pa and the bandwidth extends from 2 to 50 kHz. This sensor configuration can be used as a high sensitivity, wide band underwater acoustic sensor.

  1. Acoustic Sensor Design for Dark Matter Bubble Chamber Detectors

    PubMed Central

    Felis, Ivan; Martínez-Mora, Juan Antonio; Ardid, Miguel

    2016-01-01

    Dark matter bubble chamber detectors use piezoelectric sensors in order to detect and discriminate the acoustic signals emitted by the bubbles grown within the superheated fluid from a nuclear recoil produced by a particle interaction. These sensors are attached to the outside walls of the vessel containing the fluid. The acoustic discrimination depends strongly on the properties of the sensor attached to the outer wall of the vessel that has to meet the requirements of radiopurity and size. With the aim of optimizing the sensor system, a test bench for the characterization of the sensors has been developed. The sensor response for different piezoelectric materials, geometries, matching layers, and backing layers have been measured and contrasted with FEM simulations and analytical models. The results of these studies lead us to have a design criterion for the construction of specific sensors for the next generation of dark matter bubble chamber detectors (250 L). PMID:27294937

  2. Acoustic Sensor Design for Dark Matter Bubble Chamber Detectors.

    PubMed

    Felis, Ivan; Martínez-Mora, Juan Antonio; Ardid, Miguel

    2016-01-01

    Dark matter bubble chamber detectors use piezoelectric sensors in order to detect and discriminate the acoustic signals emitted by the bubbles grown within the superheated fluid from a nuclear recoil produced by a particle interaction. These sensors are attached to the outside walls of the vessel containing the fluid. The acoustic discrimination depends strongly on the properties of the sensor attached to the outer wall of the vessel that has to meet the requirements of radiopurity and size. With the aim of optimizing the sensor system, a test bench for the characterization of the sensors has been developed. The sensor response for different piezoelectric materials, geometries, matching layers, and backing layers have been measured and contrasted with FEM simulations and analytical models. The results of these studies lead us to have a design criterion for the construction of specific sensors for the next generation of dark matter bubble chamber detectors (250 L). PMID:27294937

  3. The trade-off characteristics of acoustic and pressure sensors for the NASP

    NASA Technical Reports Server (NTRS)

    Winkler, Martin; Bush, Chuck

    1992-01-01

    Results of a trade study for the development of pressure and acoustic sensors for use on the National Aerospace Plane (NASP) are summarized. Pressure sensors are needed to operate to 100 psia; acoustic sensors are needed that can give meaningful information about a 200 dB sound pressure level (SPL) environment. Both sensors will have to operate from a high temperature of 2000 F down to absolute zero. The main conclusions of the study are the following: (1) Diaphragm materials limit minimum size and maximum frequency response attainable. (2) No transduction is available to meet all the NASP requirements with existing technology. (3) Capacitive sensors are large relative to the requirement, have limited resolution and frequency response due to noise, and cable length is limited to approximately 20 feet. (4) Eddy current sensors are large relative to the requirement and have limited cable lengths. (5) Fiber optic sensors provide the possibility for a small sensor, even though present developments do not exhibit that characteristic. The need to use sapphire at high temperature complicates the design. Present high temperature research sensors suffer from poor resolution. A significant development effort will be required to realize the potential of fiber optics. (6) Short-term development seems to favor eddy current techniques with the penalty of larger size and reduced dynamic range for acoustic sensors. (7) Long-term development may favor fiber optics with the penalties of cost, schedule, and uncertainty.

  4. Speaker verification using combined acoustic and EM sensor signal processing

    SciTech Connect

    Ng, L C; Gable, T J; Holzrichter, J F

    2000-11-10

    Low Power EM radar-like sensors have made it possible to measure properties of the human speech production system in real-time, without acoustic interference. This greatly enhances the quality and quantity of information for many speech related applications. See Holzrichter, Burnett, Ng, and Lea, J. Acoustic. SOC. Am . 103 ( 1) 622 (1998). By combining the Glottal-EM-Sensor (GEMS) with the Acoustic-signals, we've demonstrated an almost 10 fold reduction in error rates from a speaker verification system experiment under a moderate noisy environment (-10dB).

  5. Low Bandwidth Vocoding using EM Sensor and Acoustic Signal Processing

    SciTech Connect

    Ng, L C; Holzrichter, J F; Larson, P E

    2001-10-25

    Low-power EM radar-like sensors have made it possible to measure properties of the human speech production system in real-time, without acoustic interference [1]. By combining these data with the corresponding acoustic signal, we've demonstrated an almost 10-fold bandwidth reduction in speech compression, compared to a standard 2.4 kbps LPC10 protocol used in the STU-III (Secure Terminal Unit, third generation) telephone. This paper describes a potential EM sensor/acoustic based vocoder implementation.

  6. On Modeling Eavesdropping Attacks in Underwater Acoustic Sensor Networks †

    PubMed Central

    Wang, Qiu; Dai, Hong-Ning; Li, Xuran; Wang, Hao; Xiao, Hong

    2016-01-01

    The security and privacy of underwater acoustic sensor networks has received extensive attention recently due to the proliferation of underwater activities. This paper proposes an analytical model to investigate the eavesdropping attacks in underwater acoustic sensor networks. Our analytical framework considers the impacts of various underwater acoustic channel conditions (such as the acoustic signal frequency, spreading factor and wind speed) and different hydrophones (isotropic hydrophones and array hydrophones) in terms of network nodes and eavesdroppers. We also conduct extensive simulations to evaluate the effectiveness and the accuracy of our proposed model. Empirical results show that our proposed model is quite accurate. In addition, our results also imply that the eavesdropping probability heavily depends on both the underwater acoustic channel conditions and the features of hydrophones. PMID:27213379

  7. On Modeling Eavesdropping Attacks in Underwater Acoustic Sensor Networks.

    PubMed

    Wang, Qiu; Dai, Hong-Ning; Li, Xuran; Wang, Hao; Xiao, Hong

    2016-01-01

    The security and privacy of underwater acoustic sensor networks has received extensive attention recently due to the proliferation of underwater activities. This paper proposes an analytical model to investigate the eavesdropping attacks in underwater acoustic sensor networks. Our analytical framework considers the impacts of various underwater acoustic channel conditions (such as the acoustic signal frequency, spreading factor and wind speed) and different hydrophones (isotropic hydrophones and array hydrophones) in terms of network nodes and eavesdroppers. We also conduct extensive simulations to evaluate the effectiveness and the accuracy of our proposed model. Empirical results show that our proposed model is quite accurate. In addition, our results also imply that the eavesdropping probability heavily depends on both the underwater acoustic channel conditions and the features of hydrophones. PMID:27213379

  8. Development of combined Opto-Acoustical sensor Modules

    NASA Astrophysics Data System (ADS)

    Enzenhöfer, A.; Anton, G.; Graf, K.; Hößl, J.; Katz, U.; Lahmann, R.; Neff, M.; Richardt, C.

    2012-01-01

    The faint fluxes of cosmic neutrinos expected at very high energies require large instrumented detector volumes. The necessary volumes in combination with a sufficient shielding against background constitute forbidding and complex environments (e.g. the deep sea) as sites for neutrino telescopes. To withstand these environments and to assure the data quality, the sensors have to be reliable and their operation has to be as simple as possible. A compact sensor module design including all necessary components for data acquisition and module calibration would simplify the detector mechanics and ensures the long term operability of the detector. The compact design discussed here combines optical and acoustical sensors inside one module, therefore reducing electronics and additional external instruments for calibration purposes. In this design the acoustical sensor is primary used for acoustic positioning of the module. The module may also be used for acoustic particle detection and marine science if an appropriate acoustical sensor is chosen.First tests of this design are promising concerning the task of calibration. To expand the field of application also towards acoustic particle detection further improvements concerning electromagnetic shielding and adaptation of the single components are necessary.

  9. Geo-acoustic inversion with a vector sensor array

    NASA Astrophysics Data System (ADS)

    Li, Fenghua; Zhang, Renhe; Sun, Mei

    2012-11-01

    Geo-acoustic inversion has been paid much attention in the last several decades. Various geo-acoustic inversion methods based on hydrophone arrays have been developed. However, few studies on inverting the bottom parameters with a vector sensor array have been performed. In this paper, theoretical analyses and numerical simulations show that in comparison with pressure, the vertical particle velocity has different spatial distribution, which can provide more information for geo-acoustic inversion. Two geo-acoustic inversion methods, based on coherent and incoherent matched field processing with a vector sensor array, have been developed. To establish the validity of the proposed methods, a shallow water experiment was performed in 2009. The experimental data indicates that the uncertainty of the inversion results is decreased by the coherent inversion method with a vector sensor array in comparison with the results obtained by a hydrophone array only.

  10. Fiber-optic interferometric acoustic sensors for wind tunnel applications

    NASA Technical Reports Server (NTRS)

    Cho, Y. C.

    1993-01-01

    Progress in developing fiber-optic interferometric sensors for aeroacoustic measurements in wind tunnels, performed under the NASA program, is reported. Preliminary results show that the fiber-optic interferometer sensor array is a powerful instrument for solving complex acoustic measurement problems in wind tunnels, which cannot be resolved with the conventional transducer technique.

  11. Development of novel optical fiber interferometric sensors with high sensitivity for acoustic emission detection

    NASA Astrophysics Data System (ADS)

    Deng, Jiangdong

    For the purpose of developing a new highly-sensitive and reliable fiber optical acoustic sensor capable of real-time on-line detection of acoustic emissions in power transformers, this dissertation presents the comprehensive research work on the theory, modeling, design, instrumentation, noise analysis, and performance evaluation of a diaphragm-based optical fiber acoustic (DOFIA) sensor system. The optical interference theory and the diaphragm dynamic vibration analysis form the two foundation stones of the diaphragm-based optical fiber interferometric acoustic (DOFIA) sensor. Combining these two principles, the pressure sensitivity and frequency response of the acoustic sensor system is analyzed quantitatively, which provides guidance for the practical design for the DOFIA sensor probe and system. To meet all the technical requirements for partial discharge detection, semiconductor process technologies are applied, for the first time to our knowledge, in fabricating the micro-caved diaphragm (MCD) used for the DOFIA sensor probe. The novel controlled thermal bonding method was proposed, designed, and developed to fabricate high performance DOFIA sensor probes with excellent mechanical strength and temperature stability. In addition, the signal processing unit is designed and implemented with high gain, wide band response, and ultra low noise. A systematic noise analysis is also presented to provide a better understanding of the performance limitations of the DOFIA sensor system. Based on the system noise analysis results, optimization measures are proposed to improve the system performance. Extensive experiments, including the field testing in a power transformer, have also been conducted to systematically evaluate the performance of the instrumentation systems and the sensor probes. These results clearly demonstrated the feasibility of the developed DOFIA sensor for the detection of partial discharges inside electrical power transformers, with unique advantages

  12. Optimization of surface acoustic wave-based rate sensors.

    PubMed

    Xu, Fangqian; Wang, Wen; Shao, Xiuting; Liu, Xinlu; Liang, Yong

    2015-01-01

    The optimization of an surface acoustic wave (SAW)-based rate sensor incorporating metallic dot arrays was performed by using the approach of partial-wave analysis in layered media. The optimal sensor chip designs, including the material choice of piezoelectric crystals and metallic dots, dot thickness, and sensor operation frequency were determined theoretically. The theoretical predictions were confirmed experimentally by using the developed SAW sensor composed of differential delay line-oscillators and a metallic dot array deposited along the acoustic wave propagation path of the SAW delay lines. A significant improvement in sensor sensitivity was achieved in the case of 128° YX LiNbO₃, and a thicker Au dot array, and low operation frequency were used to structure the sensor. PMID:26473865

  13. Optimization of Surface Acoustic Wave-Based Rate Sensors

    PubMed Central

    Xu, Fangqian; Wang, Wen; Shao, Xiuting; Liu, Xinlu; Liang, Yong

    2015-01-01

    The optimization of an surface acoustic wave (SAW)-based rate sensor incorporating metallic dot arrays was performed by using the approach of partial-wave analysis in layered media. The optimal sensor chip designs, including the material choice of piezoelectric crystals and metallic dots, dot thickness, and sensor operation frequency were determined theoretically. The theoretical predictions were confirmed experimentally by using the developed SAW sensor composed of differential delay line-oscillators and a metallic dot array deposited along the acoustic wave propagation path of the SAW delay lines. A significant improvement in sensor sensitivity was achieved in the case of 128° YX LiNbO3, and a thicker Au dot array, and low operation frequency were used to structure the sensor. PMID:26473865

  14. Ultrasonic waveguide sensor for acoustic monitoring of nuclear power plants

    SciTech Connect

    Mel'nikov, V.I.; Khokhlov, V.N.; Duntsev, A.V.

    1988-02-01

    Waveguide sensors are being increasingly used for acoustic emission monitoring of equipment in nuclear power plants and in systems for acoustic diagnostics of the coolant. In this paper we examine the construction of a waveguide sensor for acoustic monitoring for the example of an impedance sensor for the steam content of water coolant, intended for use in the active emission-reception mode. The dynamic properties of the sensor are determined by the construction and the dimensions of the transducer, and are usually represented by its amplitude-frequency characteristic, which, as a rule, is of the resonance type. The longitudinal-wave waveguide, made from steel wire 0.8-1.2 mm in diameter, can transmit signals in the band 50-1000 kHz. To increase the reliability and the ease of maintenance of the monitoring system the transducer and the waveguide are connected in a detachable manner.

  15. (3,1) Drive PVDF acoustic displacement sensor

    SciTech Connect

    Caspall, J.J.; Caille, G.W.; Jarzynski, J.; McCall, G.S. II

    1996-04-01

    A (3,1) drive piezofilm vibration sensor is introduced. Operated above the lumped element resonance frequency of 600 Hz, the sensor delivers a voltage signal proportional to displacement over the frequency range of 2 kHz to 8 kHz. It is anticipated that the sensor response is flat above 8 kHz, but calibration has not been performed at higher frequencies. The sensor is very sensitive, detecting acoustic displacements as small as 10{sup {minus}5} nm. Because of its simple design the sensor is robust and easy to assemble. {copyright} {ital 1996 American Institute of Physics.}

  16. Biomimetic smart sensors for autonomous robotic behavior I: acoustic processing

    NASA Astrophysics Data System (ADS)

    Deligeorges, Socrates; Xue, Shuwan; Soloway, Aaron; Lichtenstein, Lee; Gore, Tyler; Hubbard, Allyn

    2009-05-01

    Robotics are rapidly becoming an integral tool on the battlefield and in homeland security, replacing humans in hazardous conditions. To enhance the effectiveness of robotic assets and their interaction with human operators, smart sensors are required to give more autonomous function to robotic platforms. Biologically inspired sensors are an essential part of this development of autonomous behavior and can increase both capability and performance of robotic systems. Smart, biologically inspired acoustic sensors have the potential to extend autonomous capabilities of robotic platforms to include sniper detection, vehicle tracking, personnel detection, and general acoustic monitoring. The key to enabling these capabilities is biomimetic acoustic processing using a time domain processing method based on the neural structures of the mammalian auditory system. These biologically inspired algorithms replicate the extremely adaptive processing of the auditory system yielding high sensitivity over broad dynamic range. The algorithms provide tremendous robustness in noisy and echoic spaces; properties necessary for autonomous function in real world acoustic environments. These biomimetic acoustic algorithms also provide highly accurate localization of both persistent and transient sounds over a wide frequency range, using baselines on the order of only inches. A specialized smart sensor has been developed to interface with an iRobot Packbot® platform specifically to enhance its autonomous behaviors in response to personnel and gunfire. The low power, highly parallel biomimetic processor, in conjunction with a biomimetic vestibular system (discussed in the companion paper), has shown the system's autonomous response to gunfire in complicated acoustic environments to be highly effective.

  17. Automotive Sensors and MEMS Technology

    NASA Astrophysics Data System (ADS)

    Nonomura, Yutaka

    - Automotive sensors are used for emission gas purification, energy conservation, car kinematic performance, safety and ITS (intelligent transportation system). The comparison of the sensor characteristics was made for their application area. Many kinds of the principles are applied for the sensors. There are two types of sensors, such as physical and chemical one. Many of the automotive sensors are physical type such as mechanical sensors. And a gas sensor is a chemical type. The sensors have been remarkably developed with the advancement of the MEMS (Micro Electro Mechanical Systems) technology. In this paper, gas, pressure, combustion pressure, acceleration, magnetic, and angular rate sensors for automotive use are explained with their features. The sensors are key devices to control cars in the engine, power train, chassis and safety systems. The environment resistance, long term reliability, and low cost are required for the automotive sensors. They are very hard to be resolved. However, the sensor technology contributes greatly to improving global environment, energy conservation, and safety. The applications of automotive sensors will be expanded with the automobile developments.

  18. New Research on MEMS Acoustic Vector Sensors Used in Pipeline Ground Markers

    PubMed Central

    Song, Xiaopeng; Jian, Zeming; Zhang, Guojun; Liu, Mengran; Guo, Nan; Zhang, Wendong

    2015-01-01

    According to the demands of current pipeline detection systems, the above-ground marker (AGM) system based on sound detection principle has been a major development trend in pipeline technology. A novel MEMS acoustic vector sensor for AGM systems which has advantages of high sensitivity, high signal-to-noise ratio (SNR), and good low frequency performance has been put forward. Firstly, it is presented that the frequency of the detected sound signal is concentrated in a lower frequency range, and the sound attenuation is relatively low in soil. Secondly, the MEMS acoustic vector sensor structure and basic principles are introduced. Finally, experimental tests are conducted and the results show that in the range of 0°∼90°, when r = 5 m, the proposed MEMS acoustic vector sensor can effectively detect sound signals in soil. The measurement errors of all angles are less than 5°. PMID:25609046

  19. Tracking sperm whales with a towed acoustic vector sensor.

    PubMed

    Thode, Aaron; Skinner, Jeff; Scott, Pam; Roswell, Jeremy; Straley, Janice; Folkert, Kendall

    2010-11-01

    Passive acoustic towed linear arrays are increasingly used to detect marine mammal sounds during mobile anthropogenic activities. However, these arrays cannot resolve between signals arriving from the port or starboard without vessel course changes or multiple cable deployments, and their performance is degraded by vessel self-noise and non-acoustic mechanical vibration. In principle acoustic vector sensors can resolve these directional ambiguities, as well as flag the presence of non-acoustic contamination, provided that the vibration-sensitive sensors can be successfully integrated into compact tow modules. Here a vector sensor module attached to the end of a 800 m towed array is used to detect and localize 1813 sperm whale "clicks" off the coast of Sitka, AK. Three methods were used to identify frequency regimes relatively free of non-acoustic noise contamination, and then the active intensity (propagating energy) of the signal was computed between 4-10 kHz along three orthogonal directions, providing unambiguous bearing estimates of two sperm whales over time. These bearing estimates are consistent with those obtained via conventional methods, but the standard deviations of the vector sensor bearing estimates are twice those of the conventionally-derived bearings. The resolved ambiguities of the bearings deduced from vessel course changes match the vector sensor predictions. PMID:21110564

  20. Acoustic sensors in the helmet detect voice and physiology

    NASA Astrophysics Data System (ADS)

    Scanlon, Michael V.

    2003-09-01

    The Army Research Laboratory has developed body-contacting acoustic sensors that detect diverse physiological sounds such as heartbeats and breaths, high quality speech, and activity. These sensors use an acoustic impedance-matching gel contained in a soft, compliant pad to enhance the body borne sounds, yet significantly repel airborne noises due to an acoustic impedance mismatch. The signals from such a sensor can be used as a microphone with embedded physiology, or a dedicated digital signal processor can process packetized data to separate physiological parameters from voice, and log parameter trends for performance surveillance. Acoustic sensors were placed inside soldier helmets to monitor voice, physiology, activity, and situational awareness clues such as bullet shockwaves from sniper activity and explosions. The sensors were also incorporated into firefighter breathing masks, neck and wrist straps, and other protective equipment. Heart rate, breath rate, blood pressure, voice and activity can be derived from these sensors (reports at www.arl.army.mil/acoustics). Having numerous sensors at various locations provides a means for array processing to reduce motion artifacts, calculate pulse transit time for passive blood pressure measurement, and the origin of blunt/penetrating traumas such as ballistic wounding. These types of sensors give us the ability to monitor soldiers and civilian emergency first-responders in demanding environments, and provide vital signs information to assess their health status and how that person is interacting with the environment and mission at hand. The Objective Force Warrior, Scorpion, Land Warrior, Warrior Medic, and other military and civilian programs can potentially benefit from these sensors.

  1. Improving the sensitivity of an interferometric fiber optic sensor for acoustic detection in rockfalls

    NASA Astrophysics Data System (ADS)

    Schenato, L.; Palmieri, L.; Autizi, E.; Galtarossa, A.; Pasuto, A.

    2013-12-01

    Being intrinsically EMI free and offering superior hostile environment operation, fiber optic sensor technology represents a valuable alternative to standard sensors technology in landslides monitoring. Here an improved design for a fiber optic sensor to be used for ultrasonic acoustic detection in rockfall monitoring is proposed. Basically, the original sensor consists of a fiber coil tightly wound on an aluminum flanged hollow mandrel that acts as the sensing arm of a Mach-Zehnder interferometer [1]. To further improve sensor sensitivity, the use of a special fiber, with polyimide coating and very large numerical aperture, has been proposed and tested. The polyimide coating, harder and thinner than standard coating, makes the fiber more sensitive to acoustic waves and increase the coupling efficiency between fiber and mandrel. At the same time, a fiber with very large numerical aperture allows for a much smaller bending radius and thus enables the design of a sensor with reduced size, or with the same external size but housing a longer fiber. Part of the research activity has been then focused toward the optimization of the shape and dimensions of the mandrel: to this aim, a large set of numerical simulations has been performed and they are here presented and discussed. The performance assessment gained with new sensors has been carried in a controlled scenario by using a block of trachyte in which the sensors have been screwed in internally threaded chemical anchors housed in holes drilled on one face of the block. Ultrasonic signals have been generated in a repeatable way by dropping a 5-mm-diameter steel ball along a steep slide. Experimental tests, carried out by firstly comparing the performance of a sensor made with special fiber with respect to the original one, have shown an increased sensitivity of almost 35 % in the detected acoustic energy. Further tests, carried out on a sensor with optimized dimensions and made with special fiber, have shown an

  2. Optical technologies for space sensor

    NASA Astrophysics Data System (ADS)

    Wang, Hu; Liu, Jie; Xue, Yaoke; Liu, Yang; Liu, Meiying; Wang, Lingguang; Yang, Shaodong; Lin, Shangmin; Chen, Su; Luo, Jianjun

    2015-10-01

    Space sensors are used in navigation sensor fields. The sun, the earth, the moon and other planets are used as frame of reference to obtain stellar position coordinates, and then to control the attitude of an aircraft. Being the "eyes" of the space sensors, Optical sensor system makes images of the infinite far stars and other celestial bodies. It directly affects measurement accuracy of the space sensor, indirectly affecting the data updating rate. Star sensor technology is the pilot for Space sensors. At present more and more attention is paid on all-day star sensor technology. By day and night measurements of the stars, the aircraft's attitude in the inertial coordinate system can be provided. Facing the requirements of ultra-high-precision, large field of view, wide spectral range, long life and high reliability, multi-functional optical system, we integration, integration optical sensors will be future space technology trends. In the meantime, optical technologies for space-sensitive research leads to the development of ultra-precision optical processing, optical and precision test machine alignment technology. It also promotes the development of long-life optical materials and applications. We have achieved such absolute distortion better than ±1um, Space life of at least 15years of space-sensitive optical system.

  3. High-sensitivity acoustic sensors from nanofibre webs

    NASA Astrophysics Data System (ADS)

    Lang, Chenhong; Fang, Jian; Shao, Hao; Ding, Xin; Lin, Tong

    2016-03-01

    Considerable interest has been devoted to converting mechanical energy into electricity using polymer nanofibres. In particular, piezoelectric nanofibres produced by electrospinning have shown remarkable mechanical energy-to-electricity conversion ability. However, there is little data for the acoustic-to-electric conversion of electrospun nanofibres. Here we show that electrospun piezoelectric nanofibre webs have a strong acoustic-to-electric conversion ability. Using poly(vinylidene fluoride) as a model polymer and a sensor device that transfers sound directly to the nanofibre layer, we show that the sensor devices can detect low-frequency sound with a sensitivity as high as 266 mV Pa-1. They can precisely distinguish sound waves in low to middle frequency region. These features make them especially suitable for noise detection. Our nanofibre device has more than five times higher sensitivity than a commercial piezoelectric poly(vinylidene fluoride) film device. Electrospun piezoelectric nanofibres may be useful for developing high-performance acoustic sensors.

  4. Dual output acoustic wave sensor for molecular identification

    DOEpatents

    Frye, Gregory C.; Martin, Stephen J.

    1991-01-01

    A method of identification and quantification of absorbed chemical species by measuring changes in both the velocity and the attenuation of an acoustic wave traveling through a thin film into which the chemical species is sorbed. The dual output response provides two independent sensor responses from a single sensing device thereby providing twice as much information as a single output sensor. This dual output technique and analysis allows a single sensor to provide both the concentration and the identity of a chemical species or permits the number of sensors required for mixtures to be reduced by a factor of two.

  5. Embedded Acoustic Sensor Array for Engine Fan Noise Source Diagnostic Test: Feasibility of Noise Telemetry via Wireless Smart Sensors

    NASA Technical Reports Server (NTRS)

    Zaman, Afroz; Bauch, Matthew; Raible, Daniel

    2011-01-01

    Aircraft engines have evolved into a highly complex system to meet ever-increasing demands. The evolution of engine technologies has primarily been driven by fuel efficiency, reliability, as well as engine noise concerns. One of the sources of engine noise is pressure fluctuations that are induced on the stator vanes. These local pressure fluctuations, once produced, propagate and coalesce with the pressure waves originating elsewhere on the stator to form a spinning pressure pattern. Depending on the duct geometry, air flow, and frequency of fluctuations, these spinning pressure patterns are self-sustaining and result in noise which eventually radiate to the far-field from engine. To investigate the nature of vane pressure fluctuations and the resulting engine noise, unsteady pressure signatures from an array of embedded acoustic sensors are recorded as a part of vane noise source diagnostics. Output time signatures from these sensors are routed to a control and data processing station adding complexity to the system and cable loss to the measured signal. "Smart" wireless sensors have data processing capability at the sensor locations which further increases the potential of wireless sensors. Smart sensors can process measured data locally and transmit only the important information through wireless communication. The aim of this wireless noise telemetry task was to demonstrate a single acoustic sensor wireless link for unsteady pressure measurement, and thus, establish the feasibility of distributed smart sensors scheme for aircraft engine vane surface unsteady pressure data transmission and characterization.

  6. Sensor technology for smart homes.

    PubMed

    Ding, Dan; Cooper, Rory A; Pasquina, Paul F; Fici-Pasquina, Lavinia

    2011-06-01

    A smart home is a residence equipped with technology that observes the residents and provides proactive services. Most recently, it has been introduced as a potential solution to support independent living of people with disabilities and older adults, as well as to relieve the workload from family caregivers and health providers. One of the key supporting features of a smart home is its ability to monitor the activities of daily living and safety of residents, and in detecting changes in their daily routines. With the availability of inexpensive low-power sensors, radios, and embedded processors, current smart homes are typically equipped with a large amount of networked sensors which collaboratively process and make deductions from the acquired data on the state of the home as well as the activities and behaviors of its residents. This article reviews sensor technology used in smart homes with a focus on direct environment sensing and infrastructure mediated sensing. The article also points out the strengths and limitations of different sensor technologies, as well as discusses challenges and opportunities from clinical, technical, and ethical perspectives. It is recommended that sensor technologies for smart homes address actual needs of all stake holders including end users, their family members and caregivers, and their doctors and therapists. More evidence on the appropriateness, usefulness, and cost benefits analysis of sensor technologies for smart homes is necessary before these sensors should be widely deployed into real-world residential settings and successfully integrated into everyday life and health care services. PMID:21531517

  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. Electron tunnel sensor technology

    NASA Technical Reports Server (NTRS)

    Kenny, T. W.; Waltman, S. B.; Reynolds, J. K.; Kaiser, W. J.

    1991-01-01

    Researchers designed and constructed a novel electron tunnel sensor which takes advantage of the mechanical properties of micro-machined silicon. For the first time, electrostatic forces are used to control the tunnel electrode separation, thereby avoiding the thermal drift and noise problems associated with piezoelectric actuators. The entire structure is composed of micro-machined silicon single crystals, including a folded cantilever spring and a tip. The application of this sensor to the development of a sensitive accelerometer is described.

  9. Image Sensors Enhance Camera Technologies

    NASA Technical Reports Server (NTRS)

    2010-01-01

    In the 1990s, a Jet Propulsion Laboratory team led by Eric Fossum researched ways of improving complementary metal-oxide semiconductor (CMOS) image sensors in order to miniaturize cameras on spacecraft while maintaining scientific image quality. Fossum s team founded a company to commercialize the resulting CMOS active pixel sensor. Now called the Aptina Imaging Corporation, based in San Jose, California, the company has shipped over 1 billion sensors for use in applications such as digital cameras, camera phones, Web cameras, and automotive cameras. Today, one of every three cell phone cameras on the planet feature Aptina s sensor technology.

  10. Theory for a gas composition sensor based on acoustic properties

    NASA Technical Reports Server (NTRS)

    Phillips, Scott; Dain, Yefim; Lueptow, Richard M.

    2003-01-01

    Sound travelling through a gas propagates at different speeds and its intensity attenuates to different degrees depending upon the composition of the gas. Theoretically, a real-time gaseous composition sensor could be based on measuring the sound speed and the acoustic attenuation. To this end, the speed of sound was modelled using standard relations, and the acoustic attenuation was modelled using the theory for vibrational relaxation of gas molecules. The concept for a gas composition sensor is demonstrated theoretically for nitrogen-methane-water and hydrogen-oxygen-water mixtures. For a three-component gas mixture, the measured sound speed and acoustic attenuation each define separate lines in the composition plane of two of the gases. The intersection of the two lines defines the gas composition. It should also be possible to use the concept for mixtures of more than three components, if the nature of the gas composition is known to some extent.

  11. Theory for a gas composition sensor based on acoustic properties.

    PubMed

    Phillips, Scott; Dain, Yefim; Lueptow, Richard M

    2003-01-01

    Sound travelling through a gas propagates at different speeds and its intensity attenuates to different degrees depending upon the composition of the gas. Theoretically, a real-time gaseous composition sensor could be based on measuring the sound speed and the acoustic attenuation. To this end, the speed of sound was modelled using standard relations, and the acoustic attenuation was modelled using the theory for vibrational relaxation of gas molecules. The concept for a gas composition sensor is demonstrated theoretically for nitrogen-methane-water and hydrogen-oxygen-water mixtures. For a three-component gas mixture, the measured sound speed and acoustic attenuation each define separate lines in the composition plane of two of the gases. The intersection of the two lines defines the gas composition. It should also be possible to use the concept for mixtures of more than three components, if the nature of the gas composition is known to some extent. PMID:14552356

  12. Vector Acoustics, Vector Sensors, and 3D Underwater Imaging

    NASA Astrophysics Data System (ADS)

    Lindwall, D.

    2007-12-01

    Vector acoustic data has two more dimensions of information than pressure data and may allow for 3D underwater imaging with much less data than with hydrophone data. The vector acoustic sensors measures the particle motions due to passing sound waves and, in conjunction with a collocated hydrophone, the direction of travel of the sound waves. When using a controlled source with known source and sensor locations, the reflection points of the sound field can be determined with a simple trigonometric calculation. I demonstrate this concept with an experiment that used an accelerometer based vector acoustic sensor in a water tank with a short-pulse source and passive scattering targets. The sensor consists of a three-axis accelerometer and a matched hydrophone. The sound source was a standard transducer driven by a short 7 kHz pulse. The sensor was suspended in a fixed location and the hydrophone was moved about the tank by a robotic arm to insonify the tank from many locations. Several floats were placed in the tank as acoustic targets at diagonal ranges of approximately one meter. The accelerometer data show the direct source wave as well as the target scattered waves and reflections from the nearby water surface, tank bottom and sides. Without resorting to the usual methods of seismic imaging, which in this case is only two dimensional and relied entirely on the use of a synthetic source aperture, the two targets, the tank walls, the tank bottom, and the water surface were imaged. A directional ambiguity inherent to vector sensors is removed by using collocated hydrophone data. Although this experiment was in a very simple environment, it suggests that 3-D seismic surveys may be achieved with vector sensors using the same logistics as a 2-D survey that uses conventional hydrophones. This work was supported by the Office of Naval Research, program element 61153N.

  13. Miniature fiber acoustic sensors using a photonic-crystal membrane

    NASA Astrophysics Data System (ADS)

    Jo, Wonuk; Akkaya, Onur C.; Solgaard, Olav; Digonnet, Michel J. F.

    2013-12-01

    This paper discusses recent developments in fiber acoustic sensors utilizing a miniature Fabry-Perot (FP) interferometer fabricated at the tip of a fiber. The FP is made of a high-reflectivity photonic-crystal membrane placed ˜30 μm from the reflective end of a single-mode fiber. When exposed to an acoustic wave the compliant membrane vibrates, and this vibration is detected as a modulation of the optical power reflected by the FP. The interferometer is enclosed in a sensor head designed, with the assistance of an electro-mechanical model, to minimize squeezed-film damping of the thin air gap between the reflectors and obtain a good acoustic response. The sensor head is fabricated out of silica elements and assembled with silicate bonding to minimize thermal expansion and ensure thermal stability. In the first sensor of this type the reflector at the fiber tip is a gold coating. It exhibits an average minimum detectable pressure (MDP) of 33 μPa/√Hz (1-30 kHz), a high thermal stability, and a weak polarization dependence. The second sensor incorporates several improvements, including a larger membrane for increased vibration amplitude, and higher reflectivity mirrors (PC and fiber tip) for increased displacement sensitivity. Its measured response is flat between ˜600 Hz and 20 kHz, with a normalized sensitivity as high as ˜0.17 Pa-1. Between 1 kHz and 30 kHz its average MDP is ˜2.6 μPa/√Hz, the lowest reported value for a fiber acoustic sensor this small. These results demonstrate the promising potential of this class of stable and compact optical sensors for highly sensitive detection in the audible range.

  14. Impedance analysis of nano thickness layered AlGaN acoustic sensor deposited by thermionic vacuum arc

    NASA Astrophysics Data System (ADS)

    Özen, Soner; Bilgiç, Eyüp; Gülmez, Gülay; Şenay, Volkan; Pat, Suat; Korkmaz, Şadan; Mohammadigharehbagh, Reza

    2016-03-01

    In this study, AlGaN acoustic sensor was deposited on aluminum metal substrate by thermionic vacuum arc (TVA) method for the first time. Gallium materials are used in many applications for optoelectronic device and semiconductor technology. Thermionic vacuum arc is the deposition technology for the variously materials and applications field. The thickness of the acoustic sensor is in deposited as nano layer. Impedance analyses were realized. Also, TVA production parameters and some properties of the deposited layers were investigated. TVA is a fast deposition technology for the gallium compounds and doped gallium compounds. Obtained results show that AlGaN materials are very promising materials. Moreover, these acoustic sensors have been produced by TVA technology.

  15. Acoustic-sensor-based detection of damage in composite aircraft structures

    NASA Astrophysics Data System (ADS)

    Foote, Peter; Martin, Tony; Read, Ian

    2004-03-01

    Acoustic emission detection is a well-established method of locating and monitoring crack development in metal structures. The technique has been adapted to test facilities for non-destructive testing applications. Deployment as an operational or on-line automated damage detection technology in vehicles is posing greater challenges. A clear requirement of potential end-users of such systems is a level of automation capable of delivering low-level diagnosis information. The output from the system is in the form of "go", "no-go" indications of structural integrity or immediate maintenance actions. This level of automation requires significant data reduction and processing. This paper describes recent trials of acoustic emission detection technology for the diagnosis of damage in composite aerospace structures. The technology comprises low profile detection sensors using piezo electric wafers encapsulated in polymer film ad optical sensors. Sensors are bonded to the structure"s surface and enable acoustic events from the loaded structure to be located by triangulation. Instrumentation has been enveloped to capture and parameterise the sensor data in a form suitable for low-bandwidth storage and transmission.

  16. 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.

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

    SciTech Connect

    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.

  18. Sensor technology for smart structures

    NASA Technical Reports Server (NTRS)

    Rogowski, R. S.; Heyman, J. S.; Holben, M. S., Jr.; Dehart, D. W.; Doederlein, T.

    1989-01-01

    Advanced aerospace structures are discussed that will very likely be fabricated with integral sensors, actuators, and microprocessors for monitoring and dynamic control of configuration. The concept of 'smart structures' integrates fiber-optic sensor technology with advanced composite materials, whereby the optical fibers are embedded in a composite material and provide internal sensing capability for monitoring parameters which are important for the safety, performance, and reliability of the material and the structure. Along with other research facilities, NASA has initiated a cooperative program to design, fabricate, and test composite trusses, tubes, and flat panels with embedded optical fibers for testing and developing prototype smart structures. It is shown that fiber-optic sensor technology can be combined with advanced material and structure concepts to produce a new class of materials with internal sensors for health monitoring of structures.

  19. A Secure Communication Suite for Underwater Acoustic Sensor Networks

    PubMed Central

    Dini, Gianluca; Duca, Angelica Lo

    2012-01-01

    In this paper we describe a security suite for Underwater Acoustic Sensor Networks comprising both fixed and mobile nodes. The security suite is composed of a secure routing protocol and a set of cryptographic primitives aimed at protecting the confidentiality and the integrity of underwater communication while taking into account the unique characteristics and constraints of the acoustic channel. By means of experiments and simulations based on real data, we show that the suite is suitable for an underwater networking environment as it introduces limited, and sometimes negligible, communication and power consumption overhead. PMID:23202204

  20. Coded acoustic wave sensors and system using time diversity

    NASA Technical Reports Server (NTRS)

    Solie, Leland P. (Inventor); Hines, Jacqueline H. (Inventor)

    2012-01-01

    An apparatus and method for distinguishing between sensors that are to be wirelessly detected is provided. An interrogator device uses different, distinct time delays in the sensing signals when interrogating the sensors. The sensors are provided with different distinct pedestal delays. Sensors that have the same pedestal delay as the delay selected by the interrogator are detected by the interrogator whereas other sensors with different pedestal delays are not sensed. Multiple sensors with a given pedestal delay are provided with different codes so as to be distinguished from one another by the interrogator. The interrogator uses a signal that is transmitted to the sensor and returned by the sensor for combination and integration with the reference signal that has been processed by a function. The sensor may be a surface acoustic wave device having a differential impulse response with a power spectral density consisting of lobes. The power spectral density of the differential response is used to determine the value of the sensed parameter or parameters.

  1. Cloaking an acoustic sensor with single-negative materials

    SciTech Connect

    Cai, Chen; Zhu, Xue-Feng; Xu, Tao; Zou, Xin-Ye; Liang, Bin; Cheng, Jian-Chun

    2015-07-15

    In this review, a brief introduction is given to the development of acoustic superlens cloaks that allow the cloaked object to receive signals while its presence is not sensed by the surrounding, which can be regarded as “cloaking an acoustic sensor”. Remarkably, the designed cloak consists of single-negative materials with parameters independent of the background medium or the sensor system, which is proven to be a magnifying superlens. This has facilitated significantly the design and fabrication of acoustic cloaks that generally require double-negative materials with customized parameters. Such innovative design has then been simplified further as a multi-layered structure comprising of two alternately arranged complementary media with homogeneous isotropic single-negative materials. Based on this, a scattering analyses method is developed for the numerical simulation of such multi-layered cloak structures, which may serve as an efficient approach for the investigation on such devices.

  2. An invisible acoustic sensor based on parity-time symmetry.

    PubMed

    Fleury, Romain; Sounas, Dimitrios; Alù, Andrea

    2015-01-01

    Sensing an incoming signal is typically associated with absorbing a portion of its energy, inherently perturbing the measurement and creating reflections and shadows. Here, in contrast, we demonstrate a non-invasive, shadow-free, invisible sensor for airborne sound waves at audible frequencies, which fully absorbs the impinging signal, without at the same time perturbing its own measurement or creating a shadow. This unique sensing device is based on the unusual scattering properties of a parity-time (PT) symmetric metamaterial device formed by a pair of electro-acoustic resonators loaded with suitably tailored non-Foster electrical circuits, constituting the acoustic equivalent of a coherent perfect absorber coupled to a coherent laser. Beyond the specific application to non-invasive sensing, our work broadly demonstrates the unique relevance of PT-symmetric metamaterials for acoustics, loss compensation and extraordinary wave manipulation. PMID:25562746

  3. Multiplexing Technology for Acoustic Emission Monitoring of Aerospace Vehicles

    NASA Technical Reports Server (NTRS)

    Prosser, William; Percy, Daniel

    2003-01-01

    The initiation and propagation of damage mechanisms such as cracks and delaminations generate acoustic waves, which propagate through a structure. These waves can be detected and analyzed to provide the location and severity of damage as part of a structural health monitoring (SHM) system. This methodology of damage detection is commonly known as acoustic emission (AE) monitoring, and is widely used on a variety of applications on civil structures. AE has been widely considered for SHM of aerospace vehicles. Numerous successful ground and flight test demonstrations have been performed, which show the viability of the technology for damage monitoring in aerospace structures. However, one significant current limitation for application of AE techniques on aerospace vehicles is the large size, mass, and power requirements for the necessary monitoring instrumentation. To address this issue, a prototype multiplexing approach has been developed and demonstrated in this study, which reduces the amount of AE monitoring instrumentation required. Typical time division multiplexing techniques that are commonly used to monitor strain, pressure and temperature sensors are not applicable to AE monitoring because of the asynchronous and widely varying rates of AE signal occurrence. Thus, an event based multiplexing technique was developed. In the initial prototype circuit, inputs from eight sensors in a linear array were multiplexed into two data acquisition channels. The multiplexer rapidly switches, in less than one microsecond, allowing the signals from two sensors to be acquired by a digitizer. The two acquired signals are from the sensors on either side of the trigger sensor. This enables the capture of the first arrival of the waves, which cannot be accomplished with the signal from the trigger sensor. The propagation delay to the slightly more distant neighboring sensors makes this possible. The arrival time from this first arrival provides a more accurate source location

  4. Bearing estimation with acoustic vector-sensor arrays

    SciTech Connect

    Hawkes, M.; Nehorai, A.

    1996-04-01

    We consider direction-of-arrival (DOA) estimation using arrays of acoustic vector sensors in free space, and derive expressions for the Cram{acute e}r-Rao bound on the DOA parameters when there is a single source. The vector-sensor array is seen to have improved performance over the traditional scalar-sensor (pressure-sensor) array for two distinct reasons: its elements have an inherent directional sensitivity and the array makes a greater number of measurements. The improvement is greatest for small array apertures and low signal-to-noise ratios. Examination of the conventional beamforming and Capon DOA estimators shows that vector-sensor arrays can completely resolve the bearing, even with a linear array, and can remove the ambiguities associated with spatial undersampling. We also propose and analyze a diversely-oriented array of velocity sensors that possesses some of the advantages of the vector-sensor array without the increase in hardware and computation. In addition, in certain scenarios it can avoid problems with spatially correlated noise that the vector-sensor array may suffer. {copyright} {ital 1996 American Institute of Physics.}

  5. High-performance air acoustic detection and classification sensor

    NASA Astrophysics Data System (ADS)

    Porter, Richard; Raines, Robert; Jones, Barry

    2009-05-01

    Acoustic signals are a principal detection modality for unattended sensor systems. However, the performance of these systems is frequently suboptimal due to insufficient dynamic range in small systems or excess power consumption in larger systems. This paper discusses an approach to developing an unattended ground sensor (UGS) system that has the best features of both worlds. This system, developed by McQ Inc., has exceptional dynamic range (> 100 dB) while operating at power levels of 1.5-5 watts. The system also has a user definable signal parameter library and automated detection methodology that will be described.

  6. 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.

  7. Classifiers utilized to enhance acoustic based sensors to identify round types of artillery/mortar

    NASA Astrophysics Data System (ADS)

    Grasing, David; Desai, Sachi; Morcos, Amir

    2008-04-01

    Feature extraction methods based on the statistical analysis of the change in event pressure levels over a period and the level of ambient pressure excitation facilitate the development of a robust classification algorithm. The features reliably discriminates mortar and artillery variants via acoustic signals produced during the launch events. Utilizing acoustic sensors to exploit the sound waveform generated from the blast for the identification of mortar and artillery variants as type A, etcetera through analysis of the waveform. Distinct characteristics arise within the different mortar/artillery variants because varying HE mortar payloads and related charges emphasize varying size events at launch. The waveform holds various harmonic properties distinct to a given mortar/artillery variant that through advanced signal processing and data mining techniques can employed to classify a given type. The skewness and other statistical processing techniques are used to extract the predominant components from the acoustic signatures at ranges exceeding 3000m. Exploiting these techniques will help develop a feature set highly independent of range, providing discrimination based on acoustic elements of the blast wave. Highly reliable discrimination will be achieved with a feedforward neural network classifier trained on a feature space derived from the distribution of statistical coefficients, frequency spectrum, and higher frequency details found within different energy bands. The processes that are described herein extend current technologies, which emphasis acoustic sensor systems to provide such situational awareness.

  8. Method for Fabricating Piezoelectric Polymer Acoustic Sensors

    NASA Technical Reports Server (NTRS)

    Hall, Thomas E., Jr. (Inventor); Bryant, Timothy D. (Inventor)

    1998-01-01

    A method for forming a sensor includes providing a first and a second film and bonding an internal connection tab there between. The internal connection tab is positioned between the inner surfaces of the first and second film. Then, a conductive adhesive is applied to either the tab or to the inner film surfaces such that the inner surfaces of the film and the tab are electrically connected. Finally, the films are pressed together to bond the film together with the internal connection tab in between.

  9. A micro-Doppler sonar for acoustic surveillance in sensor networks

    NASA Astrophysics Data System (ADS)

    Zhang, Zhaonian

    Wireless sensor networks have been employed in a wide variety of applications, despite the limited energy and communication resources at each sensor node. Low power custom VLSI chips implementing passive acoustic sensing algorithms have been successfully integrated into an acoustic surveillance unit and demonstrated for detection and location of sound sources. In this dissertation, I explore active and passive acoustic sensing techniques, signal processing and classification algorithms for detection and classification in a multinodal sensor network environment. I will present the design and characterization of a continuous-wave micro-Doppler sonar to image objects with articulated moving components. As an example application for this system, we use it to image gaits of humans and four-legged animals. I will present the micro-Doppler gait signatures of a walking person, a dog and a horse. I will discuss the resolution and range of this micro-Doppler sonar and use experimental results to support the theoretical analyses. In order to reduce the data rate and make the system amenable to wireless sensor networks, I will present a second micro-Doppler sonar that uses bandpass sampling for data acquisition. Speech recognition algorithms are explored for biometric identifications from one's gait, and I will present and compare the classification performance of the two systems. The acoustic micro-Doppler sonar design and biometric identification results are the first in the field as the previous work used either video camera or microwave technology. I will also review bearing estimation algorithms and present results of applying these algorithms for bearing estimation and tracking of moving vehicles. Another major source of the power consumption at each sensor node is the wireless interface. To address the need of low power communications in a wireless sensor network, I will also discuss the design and implementation of ultra wideband transmitters in a three dimensional

  10. High-sensitivity acoustic sensors from nanofibre webs

    PubMed Central

    Lang, Chenhong; Fang, Jian; Shao, Hao; Ding, Xin; Lin, Tong

    2016-01-01

    Considerable interest has been devoted to converting mechanical energy into electricity using polymer nanofibres. In particular, piezoelectric nanofibres produced by electrospinning have shown remarkable mechanical energy-to-electricity conversion ability. However, there is little data for the acoustic-to-electric conversion of electrospun nanofibres. Here we show that electrospun piezoelectric nanofibre webs have a strong acoustic-to-electric conversion ability. Using poly(vinylidene fluoride) as a model polymer and a sensor device that transfers sound directly to the nanofibre layer, we show that the sensor devices can detect low-frequency sound with a sensitivity as high as 266 mV Pa−1. They can precisely distinguish sound waves in low to middle frequency region. These features make them especially suitable for noise detection. Our nanofibre device has more than five times higher sensitivity than a commercial piezoelectric poly(vinylidene fluoride) film device. Electrospun piezoelectric nanofibres may be useful for developing high-performance acoustic sensors. PMID:27005010

  11. High-sensitivity acoustic sensors from nanofibre webs.

    PubMed

    Lang, Chenhong; Fang, Jian; Shao, Hao; Ding, Xin; Lin, Tong

    2016-01-01

    Considerable interest has been devoted to converting mechanical energy into electricity using polymer nanofibres. In particular, piezoelectric nanofibres produced by electrospinning have shown remarkable mechanical energy-to-electricity conversion ability. However, there is little data for the acoustic-to-electric conversion of electrospun nanofibres. Here we show that electrospun piezoelectric nanofibre webs have a strong acoustic-to-electric conversion ability. Using poly(vinylidene fluoride) as a model polymer and a sensor device that transfers sound directly to the nanofibre layer, we show that the sensor devices can detect low-frequency sound with a sensitivity as high as 266 mV Pa(-1). They can precisely distinguish sound waves in low to middle frequency region. These features make them especially suitable for noise detection. Our nanofibre device has more than five times higher sensitivity than a commercial piezoelectric poly(vinylidene fluoride) film device. Electrospun piezoelectric nanofibres may be useful for developing high-performance acoustic sensors. PMID:27005010

  12. Development of a MEMS acoustic emission sensor system

    NASA Astrophysics Data System (ADS)

    Greve, David W.; Oppenheim, Irving J.; Wu, Wei; Wright, Amelia P.

    2007-04-01

    An improved multi-channel MEMS chip for acoustic emission sensing has been designed and fabricated in 2006 to create a device that is smaller in size, superior in sensitivity, and more practical to manufacture than earlier designs. The device, fabricated in the MUMPS process, contains four resonant-type capacitive transducers in the frequency range between 100 kHz and 500 kHz on a chip with an area smaller than 2.5 sq. mm. The completed device, with its circuit board, electronics, housing, and connectors, possesses a square footprint measuring 25 mm x 25 mm. The small footprint is an important attribute for an acoustic emission sensor, because multiple sensors must typically be arrayed around a crack location. Superior sensitivity was achieved by a combination of four factors: the reduction of squeeze film damping, a resonant frequency approximating a rigid body mode rather than a bending mode, a ceramic package providing direct acoustic coupling to the structural medium, and high-gain amplifiers implemented on a small circuit board. Manufacture of the system is more practical because of higher yield (lower unit costs) in the MUMPS fabrication task and because of a printed circuit board matching the pin array of the MEMS chip ceramic package for easy assembly and compactness. The transducers on the MEMS chip incorporate two major mechanical improvements, one involving squeeze film damping and one involving the separation of resonance modes. For equal proportions of hole area to plate area, a triangular layout of etch holes reduces squeeze film damping as compared to the conventional square layout. The effect is modeled analytically, and is verified experimentally by characterization experiments on the new transducers. Structurally, the transducers are plates with spring supports; a rigid plate would be the most sensitive transducer, and bending decreases the sensitivity. In this chip, the structure was designed for an order-of-magnitude separation between the first

  13. Zinc oxide thin film acoustic sensor

    SciTech Connect

    Mohammed, Ali Jasim; Salih, Wafaa Mahdi; Hassan, Marwa Abdul Muhsien; Nusseif, Asmaa Deiaa; Kadhum, Haider Abdullah; Mansour, Hazim Louis

    2013-12-16

    This paper reports the implementation of (750 nm) thickness of Zinc Oxide (ZnO) thin film for the piezoelectric pressure sensors. The film was prepared and deposited employing the spray pyrolysis technique. XRD results show that the growth preferred orientation is the (002) plane. A polycrystalline thin film (close to mono crystallite like) was obtained. Depending on the Scanning Electron Microscopy photogram, the film homogeneity and thickness were shown. The resonance frequency measured (about 19 kHz) and the damping coefficient was calculated and its value was found to be about (2.5538), the thin film be haves as homogeneous for under and over damped. The thin film pressure sensing was approximately exponentially related with frequency, the thin film was observed to has a good response for mechanical stresses also it is a good material for the piezoelectric properties.

  14. Zinc oxide thin film acoustic sensor

    NASA Astrophysics Data System (ADS)

    Mohammed, Ali Jasim; Salih, Wafaa Mahdi; Hassan, Marwa Abdul Muhsien; Mansour, Hazim Louis; Nusseif, Asmaa Deiaa; Kadhum, Haider Abdullah

    2013-12-01

    This paper reports the implementation of (750 nm) thickness of Zinc Oxide (ZnO) thin film for the piezoelectric pressure sensors. The film was prepared and deposited employing the spray pyrolysis technique. XRD results show that the growth preferred orientation is the (002) plane. A polycrystalline thin film (close to mono crystallite like) was obtained. Depending on the Scanning Electron Microscopy photogram, the film homogeneity and thickness were shown. The resonance frequency measured (about 19 kHz) and the damping coefficient was calculated and its value was found to be about (2.5538), the thin film be haves as homogeneous for under and over damped. The thin film pressure sensing was approximately exponentially related with frequency, the thin film was observed to has a good response for mechanical stresses also it is a good material for the piezoelectric properties.

  15. Advancing microarray assembly with acoustic dispensing technology.

    PubMed

    Wong, E Y; Diamond, S L

    2009-01-01

    In the assembly of microarrays and microarray-based chemical assays and enzymatic bioassays, most approaches use pins for contact spotting. Acoustic dispensing is a technology capable of nanoliter transfers by using acoustic energy to eject liquid sample from an open source well. Although typically used for well plate transfers, when applied to microarraying, it avoids the drawbacks of undesired physical contact with the sample; difficulty in assembling multicomponent reactions on a chip by readdressing, a rigid mode of printing that lacks patterning capabilities; and time-consuming wash steps. We demonstrated the utility of acoustic dispensing by delivering human cathepsin L in a drop-on-drop fashion into individual 50-nanoliter, prespotted reaction volumes to activate enzyme reactions at targeted positions on a microarray. We generated variable-sized spots ranging from 200 to 750 microm (and higher) and handled the transfer of fluorescent bead suspensions with increasing source well concentrations of 0.1 to 10 x 10(8) beads/mL in a linear fashion. There are no tips that can clog, and liquid dispensing CVs are generally below 5%. This platform expands the toolbox for generating analytical arrays and meets needs associated with spatially addressed assembly of multicomponent microarrays on the nanoliter scale. PMID:19035650

  16. A micromachined surface acoustic wave sensor for detecting inert gases

    SciTech Connect

    Ahuja, S.; Hersam, M.; Ross, C.; Chien, H.T.; Raptis, A.C.

    1996-12-31

    Surface acoustic wave (SAW) sensors must be specifically designed for each application because many variables directly affect the acoustic wave velocity. In the present work, the authors have designed, fabricated, and tested an SAW sensor for detection of metastable states of He. The sensor consists of two sets of micromachined interdigitated transducers (IDTs) and delay lines fabricated by photolithography on a single Y-cut LiNbO{sub 3} substrate oriented for Z-propagation of the SAWs. One set is used as a reference and the other set employs a delay line coated with a titanium-based thin film sensitive to electrical conductivity changes when exposed to metastable states of He. The reference sensor is used to obtain a true frequency translation in relation to a voltage controlled oscillator. An operating frequency of 109 MHz has been used, and the IDT finger width is 8 {micro}m. Variation in electrical conductivity of the thin film at the delay line due to exposure to He is detected as a frequency shift in the assembly, which is then used as a measure of the amount of metastable He exposed to the sensing film on the SAW delay line. A variation in the He pressure versus frequency shifts indicates the extent of the metastable He interaction.

  17. Simulation of detection and beamforming with acoustical ground sensors

    NASA Astrophysics Data System (ADS)

    Wilson, D. Keith; Sadler, Brian M.; Pham, Tien

    2002-08-01

    An interactive platform has been developed for simulating the detection and direction-finding performance of battlefield acoustic ground sensors. The simulations use the Acoustic Battlefield Aid (ABFA) as a computational engine to determine the signal propagation and resulting frequency-domain signal characteristics at the receiving sensor array. There are three components to the propagation predictions: the transmission loss (signal attenuation from target to sensor), signal saturation (degree of signal randomization), and signal coherence across the beamforming array. The transmission loss is predicted with a parabolic solution to the wave equation that accounts for sound refraction and ground interactions; signal saturation and coherence are predicted from the theory for line-of-sight wave propagation through turbulence. Based on these calculations, random frequency-domain signal samples are generated. The signal samples are then mixed with noise and fed to the selected detection or beamforming algorithm. After averaging over a number of trials, results are overlaid on a terrain map to show the sensor coverage. Currently available algorithms include the Neyman-Pearson criterion and Bayes risk minimization for detection, and the conventional, MVDR, and MUSIC beamformers. Users can readily add their own algorithms through a 'plug-in' interface. The interface requires only a text file listing the algorithm parameters and defaults, and a Matlab routine or Windows dynamic link library that implements the algorithm.

  18. Passive wireless surface acoustic wave sensors for monitoring sequestration sites CO2 emission

    SciTech Connect

    Wang, Yizhong; Chyu, Minking; Wang, Qing-Ming

    2013-02-14

    University of Pittsburgh’s Transducer lab has teamed with the U.S. Department of Energy’s National Energy Technology Laboratory (DOE NETL) to conduct a comprehensive study to develop/evaluate low-cost, efficient CO2 measuring technologies for geological sequestration sites leakage monitoring. A passive wireless CO2 sensing system based on surface acoustic wave technology and carbon nanotube nanocomposite was developed. Surface acoustic wave device was studied to determine the optimum parameters. Delay line structure was adopted as basic sensor structure. CNT polymer nanocomposite was fabricated and tested under different temperature and strain condition for natural environment impact evaluation. Nanocomposite resistance increased for 5 times under pure strain, while the temperature dependence of resistance for CNT solely was -1375ppm/°C. The overall effect of temperature on nanocomposite resistance was -1000ppm/°C. The gas response of the nanocomposite was about 10% resistance increase under pure CO2 . The sensor frequency change was around 300ppm for pure CO2 . With paralyne packaging, the sensor frequency change from relative humidity of 0% to 100% at room temperature decreased from over 1000ppm to less than 100ppm. The lowest detection limit of the sensor is 1% gas concentration, with 36ppm frequency change. Wireless module was tested and showed over one foot transmission distance at preferred parallel orientation.

  19. Advanced Sensor Technologies for Next-Generation Vehicles

    SciTech Connect

    Sheen, S H; Chien, H T; Gopalsami, N; Jendrzejczyk, A; Raptis, A C

    2002-01-30

    This report summarizes the development of automobile emissions sensors at Argonne National Laboratory. Three types of sensor technologies, i.e., ultrasound, microwave, and ion-mobility spectrometry (IMS), were evaluated for engine-out emissions monitoring. Two acoustic sensor technologies, i.e., surface acoustic wave and flexural plate wave, were evaluated for detection of hydrocarbons. The microwave technique involves a cavity design and measures the shifts in resonance frequency that are a result of the presence of trace organic compounds. The IMS technique was chosen for further development into a practical emissions sensor. An IMS sensor with a radioactive {sup 63}Ni ion source was initially developed and applied to measurement of hydrocarbons and NO{sub x} emissions. For practical applications, corona and spark discharge ion sources were later developed and applied to NO{sub x} emission measurement. The concentrations of NO{sub 2} in dry nitrogen and in a typical exhaust gas mixture are presented. The sensor response to moisture was evaluated, and a cooling method to control the moisture content in the gas stream was examined. Results show that the moisture effect can be reduced by using a thermoelectric cold plate. The design and performance of a laboratory prototype sensor are described.

  20. Optical Sensor/Actuator Locations for Active Structural Acoustic Control

    NASA Technical Reports Server (NTRS)

    Padula, Sharon L.; Palumbo, Daniel L.; Kincaid, Rex K.

    1998-01-01

    Researchers at NASA Langley Research Center have extensive experience using active structural acoustic control (ASAC) for aircraft interior noise reduction. One aspect of ASAC involves the selection of optimum locations for microphone sensors and force actuators. This paper explains the importance of sensor/actuator selection, reviews optimization techniques, and summarizes experimental and numerical results. Three combinatorial optimization problems are described. Two involve the determination of the number and position of piezoelectric actuators, and the other involves the determination of the number and location of the sensors. For each case, a solution method is suggested, and typical results are examined. The first case, a simplified problem with simulated data, is used to illustrate the method. The second and third cases are more representative of the potential of the method and use measured data. The three case studies and laboratory test results establish the usefulness of the numerical methods.

  1. Localization with a mobile beacon in underwater acoustic sensor networks.

    PubMed

    Lee, Sangho; Kim, Kiseon

    2012-01-01

    Localization is one of the most important issues associated with underwater acoustic sensor networks, especially when sensor nodes are randomly deployed. Given that it is difficult to deploy beacon nodes at predetermined locations, localization schemes with a mobile beacon on the sea surface or along the planned path are inherently convenient, accurate, and energy-efficient. In this paper, we propose a new range-free Localization with a Mobile Beacon (LoMoB). The mobile beacon periodically broadcasts a beacon message containing its location. Sensor nodes are individually localized by passively receiving the beacon messages without inter-node communications. For location estimation, a set of potential locations are obtained as candidates for a node's location and then the node's location is determined through the weighted mean of all the potential locations with the weights computed based on residuals. PMID:22778597

  2. Multipoint dynamically reconfigure adaptive distributed fiber optic acoustic emission sensor (FAESense) system for condition based maintenance

    NASA Astrophysics Data System (ADS)

    Mendoza, Edgar; Prohaska, John; Kempen, Connie; Esterkin, Yan; Sun, Sunjian; Krishnaswamy, Sridhar

    2010-09-01

    This paper describes preliminary results obtained under a Navy SBIR contract by Redondo Optics Inc. (ROI), in collaboration with Northwestern University towards the development and demonstration of a next generation, stand-alone and fully integrated, dynamically reconfigurable, adaptive fiber optic acoustic emission sensor (FAESense™) system for the in-situ unattended detection and localization of shock events, impact damage, cracks, voids, and delaminations in new and aging critical infrastructures found in ships, submarines, aircraft, and in next generation weapon systems. ROI's FAESense™ system is based on the integration of proven state-of-the-art technologies: 1) distributed array of in-line fiber Bragg gratings (FBGs) sensors sensitive to strain, vibration, and acoustic emissions, 2) adaptive spectral demodulation of FBG sensor dynamic signals using two-wave mixing interferometry on photorefractive semiconductors, and 3) integration of all the sensor system passive and active optoelectronic components within a 0.5-cm x 1-cm photonic integrated circuit microchip. The adaptive TWM demodulation methodology allows the measurement of dynamic high frequnency acoustic emission events, while compensating for passive quasi-static strain and temperature drifts. It features a compact, low power, environmentally robust 1-inch x 1-inch x 4-inch small form factor (SFF) package with no moving parts. The FAESense™ interrogation system is microprocessor-controlled using high data rate signal processing electronics for the FBG sensors calibration, temperature compensation and the detection and analysis of acoustic emission signals. Its miniaturized package, low power operation, state-of-the-art data communications, and low cost makes it a very attractive solution for a large number of applications in naval and maritime industries, aerospace, civil structures, the oil and chemical industry, and for homeland security applications.

  3. Acoustic-wave sensor apparatus for analyzing a petroleum-based composition and sensing solidification of constituents therein

    DOEpatents

    Spates, J.J.; Martin, S.J.; Mansure, A.J.

    1997-08-26

    An acoustic-wave sensor apparatus and method are disclosed. The apparatus for analyzing a normally liquid petroleum-based composition includes at least one acoustic-wave device in contact with the petroleum-based composition for sensing or detecting the presence of constituents (e.g. paraffins or petroleum waxes) therein which solidify upon cooling of the petroleum-based composition below a cloud-point temperature. The acoustic-wave device can be a thickness-shear-mode device (also termed a quartz crystal microbalance), a surface-acoustic-wave device, an acoustic-plate-mode device or a flexural plate-wave device. Embodiments of the present invention can be used for measuring a cloud point, a pour point and/or a freeze point of the petroleum-based composition, and for determining a temperature characteristic of each point. Furthermore, measurements with the acoustic-wave sensor apparatus can be made off-line by using a sample having a particular petroleum-based composition; or in-situ with the petroleum-based composition contained within a pipeline or storage tank. The acoustic-wave sensor apparatus has uses in many different petroleum technology areas, including the recovery, transport, storage, refining and use of petroleum and petroleum-based products. 7 figs.

  4. Acoustic-wave sensor apparatus for analyzing a petroleum-based composition and sensing solidification of constituents therein

    DOEpatents

    Spates, James J.; Martin, Stephen J.; Mansure, Arthur J.

    1997-01-01

    An acoustic-wave sensor apparatus and method. The apparatus for analyzing a normally liquid petroleum-based composition includes at least one acoustic-wave device in contact with the petroleum-based composition for sensing or detecting the presence of constituents (e.g. paraffins or petroleum waxes) therein which solidify upon cooling of the petroleum-based composition below a cloud-point temperature. The acoustic-wave device can be a thickness-shear-mode device (also termed a quartz crystal mircrobalance), a surface-acoustic-wave device, an acoustic-plate-mode device or a flexural plate-wave device. Embodiments of the present invention can be used for measuring a cloud point, a pour point and/or a freeze point of the petroleum-based composition, and for determining a temperature characteristic of each point. Furthermore, measurements with the acoustic-wave sensor apparatus can be made off-line by using a sample having a particular petroleum-based composition; or in-situ with the petroleum-based composition contained within a pipeline or storage tank. The acoustic-wave sensor apparatus has uses in many different petroleum technology areas, including the recover transport, storage, refining and use of petroleum and petroleum-based products.

  5. Soldier detection using unattended acoustic and seismic sensors

    NASA Astrophysics Data System (ADS)

    Naz, P.; Hengy, S.; Hamery, P.

    2012-06-01

    During recent military conflicts, as well as for security interventions, the urban zone has taken a preponderant place. Studies have been initiated in national and in international programs to stimulate the technical innovations for these specific scenarios. For example joint field experiments have been organized by the NATO group SET-142 to evaluate the capability for the detection and localization of snipers, mortars or artillery guns using acoustic devices. Another important operational need corresponds to the protection of military sites or buildings. In this context, unattended acoustic and seismic sensors are envisaged to contribute to the survey of specific points by the detection of approaching enemy soldiers. This paper describes some measurements done in an anechoic chamber and in free field to characterize typical sounds generated by the soldier activities (walking, crawling, weapon handling, radio communication, clothing noises...). Footstep, speech and some specific impulsive sounds are detectable at various distances from the source. Such detection algorithms may be easily merged with the existing weapon firing detection algorithms to provide a more generic "battlefield acoustic" early warning system. Results obtained in various conditions (grassy terrain, gravel path, road, forest) will be presented. A method to extrapolate the distances of detection has been developed, based on an acoustic propagation model and applied to the laboratory measurements.

  6. 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.

  7. Physically based simulation model for acoustic sensor robot navigation.

    PubMed

    Kuc, R; Siegel, M W

    1987-06-01

    A computer model is described that combines concepts from the fields of acoustics, linear system theory, and digital signal processing to simulate an acoustic sensor navigation system using time-of-flight ranging. By separating the transmitter/receiver into separate components and assuming mirror-like reflectors, closed-form solutions for the reflections from corners, edges, and walls are determined as a function of transducer size, location, and orientation. A floor plan consisting of corners, walls, and edges is efficiently encoded to indicate which of these elements contribute to a particular pulse-echo response. Sonar maps produced by transducers having different resonant frequencies and transmitted pulse waveforms can then be simulated efficiently. Examples of simulated sonar maps of two floor plans illustrate the performance of the model. Actual sonar maps are presented to verify the simulation results. PMID:21869438

  8. Single-sensor multispeaker listening with acoustic metamaterials.

    PubMed

    Xie, Yangbo; Tsai, Tsung-Han; Konneker, Adam; Popa, Bogdan-Ioan; Brady, David J; Cummer, Steven A

    2015-08-25

    Designing a "cocktail party listener" that functionally mimics the selective perception of a human auditory system has been pursued over the past decades. By exploiting acoustic metamaterials and compressive sensing, we present here a single-sensor listening device that separates simultaneous overlapping sounds from different sources. The device with a compact array of resonant metamaterials is demonstrated to distinguish three overlapping and independent sources with 96.67% correct audio recognition. Segregation of the audio signals is achieved using physical layer encoding without relying on source characteristics. This hardware approach to multichannel source separation can be applied to robust speech recognition and hearing aids and may be extended to other acoustic imaging and sensing applications. PMID:26261314

  9. Single-sensor multispeaker listening with acoustic metamaterials

    PubMed Central

    Xie, Yangbo; Tsai, Tsung-Han; Konneker, Adam; Popa, Bogdan-Ioan; Brady, David J.; Cummer, Steven A.

    2015-01-01

    Designing a “cocktail party listener” that functionally mimics the selective perception of a human auditory system has been pursued over the past decades. By exploiting acoustic metamaterials and compressive sensing, we present here a single-sensor listening device that separates simultaneous overlapping sounds from different sources. The device with a compact array of resonant metamaterials is demonstrated to distinguish three overlapping and independent sources with 96.67% correct audio recognition. Segregation of the audio signals is achieved using physical layer encoding without relying on source characteristics. This hardware approach to multichannel source separation can be applied to robust speech recognition and hearing aids and may be extended to other acoustic imaging and sensing applications. PMID:26261314

  10. Sensor technology workshop: Structure and goals

    NASA Technical Reports Server (NTRS)

    Wilson, Barbara A.

    1991-01-01

    The Astrotech 21 charter for the second of three workshops is described. The purpose was to identify technology needs in the areas of electromagnetic radiation sensors, and to recommend a plan to develop the required capabilities that are not currently available. The panels chosen for this workshop focused specifically on those technologies needed for the Astrotech 21 Program including: gamma ray and x ray sensors, ultraviolet and visible sensors, direct infrared sensors, and heterodyne submillimeter wave sensors.

  11. Contributed Review: Recent developments in acoustic energy harvesting for autonomous wireless sensor nodes applications

    NASA Astrophysics Data System (ADS)

    Khan, Farid Ullah; Khattak, Muhammad Umair

    2016-02-01

    Rapid developments in micro electronics, micro fabrication, ultra-large scale of integration, ultra-low power sensors, and wireless technology have greatly reduced the power consumption requirements of wireless sensor nodes (WSNs) and make it possible to operate these devices with energy harvesters. Likewise, other energy harvesters, acoustic energy harvesters (AEHs), have been developed and are gaining swift interest in last few years. This paper presents a review of AEHs reported in the literature for the applications of WSNs. Based on transduction mechanism, there are two types of AEHs: piezoelectric acoustic energy harvesters (PEAEHs) and electromagnetic acoustic energy harvesters (EMAEHs). The reported AEHs are mostly characterized under the sound pressure level (SPL) that ranges from 45 to 161 dB. The range for resonant frequency of the produced AEHs is from 146 Hz to 24 kHz and these produced 0.68 × 10-6 μW to 30 mW power. The maximum power (30 mW) is produced by a PEAEH, when the harvester is subjected to a SPL of 161 dB and 2.64 kHz frequency. However, for EMAEHs, the maximum power reported is about 1.96 mW (at 125 dB and 143 Hz). Under the comparable SPLs, the power production by the reported EMAEHs is relatively better than that of PEAEHs, moreover, due to lower resonant frequency, the EMAEHs are more feasible for the low frequency band acoustical environment.

  12. Contributed Review: Recent developments in acoustic energy harvesting for autonomous wireless sensor nodes applications.

    PubMed

    Khan, Farid Ullah; Khattak, Muhammad Umair

    2016-02-01

    Rapid developments in micro electronics, micro fabrication, ultra-large scale of integration, ultra-low power sensors, and wireless technology have greatly reduced the power consumption requirements of wireless sensor nodes (WSNs) and make it possible to operate these devices with energy harvesters. Likewise, other energy harvesters, acoustic energy harvesters (AEHs), have been developed and are gaining swift interest in last few years. This paper presents a review of AEHs reported in the literature for the applications of WSNs. Based on transduction mechanism, there are two types of AEHs: piezoelectric acoustic energy harvesters (PEAEHs) and electromagnetic acoustic energy harvesters (EMAEHs). The reported AEHs are mostly characterized under the sound pressure level (SPL) that ranges from 45 to 161 dB. The range for resonant frequency of the produced AEHs is from 146 Hz to 24 kHz and these produced 0.68 × 10(-6) μW to 30 mW power. The maximum power (30 mW) is produced by a PEAEH, when the harvester is subjected to a SPL of 161 dB and 2.64 kHz frequency. However, for EMAEHs, the maximum power reported is about 1.96 mW (at 125 dB and 143 Hz). Under the comparable SPLs, the power production by the reported EMAEHs is relatively better than that of PEAEHs, moreover, due to lower resonant frequency, the EMAEHs are more feasible for the low frequency band acoustical environment. PMID:26931827

  13. Unique gel-coupled acoustic sensor array monitors human voice and physiology

    NASA Astrophysics Data System (ADS)

    Scanlon, Michael

    2002-11-01

    The health and performance of soldiers, firefighters, and other first responders in strenuous and hazardous environments can be continuously and remotely monitored with body-worn acoustic sensors. The Army Research Laboratory's gel-coupled acoustic physiological monitoring sensor has acoustic impedance properties similar to the skin that facilitate the transmission of body sounds into the sensor pad, yet significantly repel ambient airborne noises due to an impedance mismatch. Acoustic signal processing detects physiological events such as heartbeats, breaths, wheezes, coughs, blood pressure, activity, motion, and voice for communication and automatic speech recognition. Acoustic sensors can be in a helmet or in a strap around the neck, chest, and wrist. Although the physiological sounds have high SNR, the acoustic sensor also responds to motion-induced artifacts that sometimes obscure meaningful physiology. A noise-canceling sensor array configuration helps remove motion noise by using two acoustic sensors on the front sides of the neck and 2 additional acoustic sensors on each wrist. The motion noise detected on all 4 sensors will be dissimilar and out of phase, yet the physiology on all 4 sensors is covariant. Pulse wave transit time between neck and wrist will indicate systolic blood pressure. Data from a firefighter experiment will be presented.

  14. Understanding and exploiting the acoustic propagation delay in underwater sensor networks

    NASA Astrophysics Data System (ADS)

    Syed, Affan Ahmed

    An understanding of the key areas of difference in acoustic underwater sensor networks and their impact on network design is essential for a rapid deployment of aquatic sensornets. Such an understanding will allow system designers to harvest the vast literature of research present in RF sensornets and focus on just those key aspects that are different for acoustic sensornets. Most complexities at the physical layer will eventually be handled either by assuming short ranges or with technology advancements making complex algorithms both cost and power efficient. However, the impact of large latency and the resulting magnification of multipath will remain a great impediment for developing robust sensor networks. This thesis contributes towards an understanding of, and solutions to, the impact of latency on sensornet migration to an underwater acoustic environment. The thesis of this dissertation is that Latency-awareness allows both migration of existing terrestrial sensornet protocols and design of new underwater protocols that can overcome and exploit the large propagation delay inherent to acoustic underwater networks. We present four studies that contribute to this thesis. First, we formalize the impact of large propagation delay on networking protocols in the concept of space-time uncertainty. Second, we use the understanding developed from this concept to design the first high-latency aware time synchronization protocol for acoustic sensor networks that is able to overcome an error source unique to the underwater environment. Third, we exploit the space-time volume during medium access to propose T-Lohi, a new class of energy and throughput efficient medium access control (MAC) protocols. Last, with our protocol implementations we are able to indicate the importance of a different type of multipath which we call self-multipath. This self-multipath adversely affects the throughput of T-Lohi MAC, and to overcome this affect we develop a novel Bayesian learning

  15. Fiber-optic sensors for acoustic studies and biological applications

    NASA Astrophysics Data System (ADS)

    Zhou, Chonghua

    1997-11-01

    This study is directed at the investigation of the applicability of various fiber-optic techniques in acoustic studies and biological sensing. The acoustic studies are conducted both at low frequencies, such as in audible sound and dynamic wave propagation measurements, and at high frequencies, such as in ultrasound for nondestructive evaluation. In biological sensing, an all- fiber-optic design biosensor with evanescent-mode coupling has been implemented and an enhanced biosensor using ultrasonic localization has been studied. The type of sensor considered for audible sound measurement is based on a combination of Fabry-Perot interferometry and intensity modulation. The technique provides information on both the amplitude and direction of the vibration and thus removes fringe counting ambiguity over a wide dynamic range, and still keeps the high-sensitivity property of interferometry. A novel microbend fiber-optic strain sensor was developed and applied to static and dynamic fracture problems and dynamic wave propagation studies. Static and dynamic fracture experiments and dynamic impact experiment have been performed and the results match well with the theoretical predications and the results obtained with electrical strain gages. The application of polarimetric fiber-optic ultrasonic sensors in nondestructive evaluation of materials is also presented. Theoretical analysis and experimental optimization have been performed and both immersion testing and embedding testing of internal defects of materials have been conducted and promising results have been obtained. For biological application, a compact fiber-optic evanescent-wave sensing system with all-fiber optical design and red semiconductor-laser excitation has been developed and tested. In this system, the fluorescent signal is confined in the fiber system so the signal-to- noise ratio is greatly improved and the sensor can be operated in ambient light conditions. To further enhance this biosensor, an

  16. An acoustic vibration sensor based on tapered triple cladding fiber

    NASA Astrophysics Data System (ADS)

    Xu, Hui; Pang, Fufei; Zhao, Shiqi; Chen, Zhenyi; Wang, Tingyun

    2014-05-01

    An acoustic vibration sensor is investigated and demonstrated by using a tapered triple cladding fiber (TCF). It is fabricated by tapering a length of 2 cm TCF which is spliced between two single mode fibers (SMF). The TCF consists of core, inner cladding, middle cladding and outer cladding. After the tapering process, this structure becomes a tapered coaxial fiber coupler which presents a periodic filtering transmission spectrum. The surrounding vibration perturbation can be directly demodulated by intensity detection of the transmission power at a particular wavelength. The experimental result shows that the maximum frequency response of 700 kHz is achieved.

  17. The origin, history and future of fiber-optic interferometric acoustic sensors for US Navy applications

    NASA Astrophysics Data System (ADS)

    Cole, James H.; Bucaro, Joseph A.; Kirkendall, Clay K.; Dandridge, Anthony

    2011-05-01

    Fiber-optic interferometric acoustic sensors were first proposed for US Navy applications 36 years ago. This paper will review the origin, development and deployment of these sensors. Future applications will also be discussed.

  18. Enzyme Microarrays Assembled by Acoustic Dispensing Technology

    PubMed Central

    Wong, E. Y.; Diamond, S. L.

    2008-01-01

    Miniaturizing bioassays to the nanoliter scale for high-throughput screening reduces the consumption of reagents that are expensive or difficult to handle. Utilizing acoustic dispensing technology, nanodroplets containing 10 µM ATP (3 µCi/µL 32P) and reaction buffer in 10% glycerol were positionally dispensed to the surface of glass slides to form 40 nL compartments (100 droplets/slide) for Pim1 (Proviral integration site 1) kinase reactions. The reactions were activated by dispensing 4 nL of various levels of a pyridocarbazolo-cyclopentadienyl ruthenium-complex Pim1 inhibitor, followed by dispensing 4 nL of a Pim1 kinase and peptide substrate solution to achieve final concentrations of 150 nM enzyme and 10 µM substrate. The microarray was incubated at 30°C (97% Rh) for 1.5 hr. The spots were then blotted to phosphocellulose membranes to capture phosphorylated substrate. Using phosphor imaging to quantify the washed membranes, the assay showed that, for doses of inhibitor from 0.75 µM to 3 µM, Pim1 was increasingly inhibited. Signal-to-background ratios were as high as 165 and average coefficients of variation (CVs) for the assay were ~20%. CVs for dispensing typical working buffers were under 5%. Thus, microarrays assembled by acoustic dispensing are promising as cost-effective tools that can be used in protein assay development. PMID:18616925

  19. Enzyme microarrays assembled by acoustic dispensing technology.

    PubMed

    Wong, E Y; Diamond, S L

    2008-10-01

    Miniaturizing bioassays to the nanoliter scale for high-throughput screening reduces the consumption of reagents that are expensive or difficult to handle. Through the use of acoustic dispensing technology, nanodroplets containing 10 microM ATP (3 microCi/microL (32)P) and reaction buffer in 10% glycerol were positionally dispensed to the surface of glass slides to form 40-nL compartments (100 droplets/slide) for Pim1 (proviral integration site 1) kinase reactions. The reactions were activated by dispensing 4 nL of various levels of a pyridocarbazolo-cyclopentadienyl ruthenium complex Pim1 inhibitor, followed by dispensing 4 nL of a Pim1 kinase and peptide substrate solution to achieve final concentrations of 150 nM enzyme and 10 microM substrate. The microarray was incubated at 30 degrees C (97% R(h)) for 1.5 h. The spots were then blotted to phosphocellulose membranes to capture phosphorylated substrate. With phosphor imaging to quantify the washed membranes, the assay showed that, for doses of inhibitor from 0.75 to 3 microM, Pim1 was increasingly inhibited. Signal-to-background ratios were as high as 165, and average coefficients of variation for the assay were approximately 20%. Coefficients of variation for dispensing typical working buffers were under 5%. Thus, microarrays assembled by acoustic dispensing are promising as cost-effective tools that can be used in protein assay development. PMID:18616925

  20. Fracture of Human Femur Tissue Monitored by Acoustic Emission Sensors

    PubMed Central

    Aggelis, Dimitrios. G.; Strantza, Maria; Louis, Olivia; Boulpaep, Frans; Polyzos, Demosthenes; van Hemelrijck, Danny

    2015-01-01

    The study describes the acoustic emission (AE) activity during human femur tissue fracture. The specimens were fractured in a bending-torsion loading pattern with concurrent monitoring by two AE sensors. The number of recorded signals correlates well with the applied load providing the onset of micro-fracture at approximately one sixth of the maximum load. Furthermore, waveform frequency content and rise time are related to the different modes of fracture (bending of femur neck or torsion of diaphysis). The importance of the study lies mainly in two disciplines. One is that, although femurs are typically subjects of surgical repair in humans, detailed monitoring of the fracture with AE will enrich the understanding of the process in ways that cannot be achieved using only the mechanical data. Additionally, from the point of view of monitoring techniques, applying sensors used for engineering materials and interpreting the obtained data pose additional difficulties due to the uniqueness of the bone structure. PMID:25763648

  1. Aircraft IR/acoustic detection evaluation. Volume 2: Development of a ground-based acoustic sensor system for the detection of subsonic jet-powered aircraft

    NASA Technical Reports Server (NTRS)

    Kraft, Robert E.

    1992-01-01

    The design and performance of a ground-based acoustic sensor system for the detection of subsonic jet-powered aircraft is described and specified. The acoustic detection system performance criteria will subsequently be used to determine target detection ranges for the subject contract. Although the defined system has never been built and demonstrated in the field, the design parameters were chosen on the basis of achievable technology and overall system practicality. Areas where additional information is needed to substantiate the design are identified.

  2. Acoustic wave flow sensor using quartz thickness shear mode resonator.

    PubMed

    Qin, Lifeng; Zeng, Zijing; Cheng, Hongbin; Wang, Qing-Ming

    2009-09-01

    A quartz thickness shear mode (TSM) bulk acoustic wave resonator was used for in situ and real-time detection of liquid flow rate in this study. A special flow chamber made of 2 parallel acrylic plates was designed for flow measurement. The flow chamber has a rectangular flow channel, 2 flow reservoirs for stabilizing the fluid flow, a sensor mounting port for resonator holding, one inlet port, and one outlet port for pipe connection. A 5-MHz TSM quartz resonator was edge-bonded to the sensor mounting port with one side exposed to the flowing liquid and other side exposed to air. The electrical impedance spectra of the quartz resonator at different volumetric flow rate conditions were measured by an impedance analyzer for the extraction of the resonant frequency through a data-fitting method. The fundamental, 3rd, 5th, 7th, and 9th resonant frequency shifts were found to be around 920, 3572, 5947, 8228, and 10,300 Hz for flow rate variation from 0 to 3000 mL/min, which had a corresponding Reynolds number change from 0 to 822. The resonant frequency shifts of different modes are found to be quadratic with flow rate, which is attributed to the nonlinear effect of quartz resonator due to the effective normal pressure imposing on the resonator sensor by the flowing fluid. The results indicate that quartz TSM resonators can be used for flow sensors with characteristics of simplicity, fast response, and good repeatability. PMID:19811997

  3. A Survey on Underwater Acoustic Sensor Network Routing Protocols

    PubMed Central

    Li, Ning; Martínez, José-Fernán; Meneses Chaus, Juan Manuel; Eckert, Martina

    2016-01-01

    Underwater acoustic sensor networks (UASNs) have become more and more important in ocean exploration applications, such as ocean monitoring, pollution detection, ocean resource management, underwater device maintenance, etc. In underwater acoustic sensor networks, since the routing protocol guarantees reliable and effective data transmission from the source node to the destination node, routing protocol design is an attractive topic for researchers. There are many routing algorithms have been proposed in recent years. To present the current state of development of UASN routing protocols, we review herein the UASN routing protocol designs reported in recent years. In this paper, all the routing protocols have been classified into different groups according to their characteristics and routing algorithms, such as the non-cross-layer design routing protocol, the traditional cross-layer design routing protocol, and the intelligent algorithm based routing protocol. This is also the first paper that introduces intelligent algorithm-based UASN routing protocols. In addition, in this paper, we investigate the development trends of UASN routing protocols, which can provide researchers with clear and direct insights for further research. PMID:27011193

  4. A Survey on Underwater Acoustic Sensor Network Routing Protocols.

    PubMed

    Li, Ning; Martínez, José-Fernán; Meneses Chaus, Juan Manuel; Eckert, Martina

    2016-01-01

    Underwater acoustic sensor networks (UASNs) have become more and more important in ocean exploration applications, such as ocean monitoring, pollution detection, ocean resource management, underwater device maintenance, etc. In underwater acoustic sensor networks, since the routing protocol guarantees reliable and effective data transmission from the source node to the destination node, routing protocol design is an attractive topic for researchers. There are many routing algorithms have been proposed in recent years. To present the current state of development of UASN routing protocols, we review herein the UASN routing protocol designs reported in recent years. In this paper, all the routing protocols have been classified into different groups according to their characteristics and routing algorithms, such as the non-cross-layer design routing protocol, the traditional cross-layer design routing protocol, and the intelligent algorithm based routing protocol. This is also the first paper that introduces intelligent algorithm-based UASN routing protocols. In addition, in this paper, we investigate the development trends of UASN routing protocols, which can provide researchers with clear and direct insights for further research. PMID:27011193

  5. Characterization Test Report for the Mnemonics-UCS Wireless Surface Acoustic Wave Sensor System

    NASA Technical Reports Server (NTRS)

    Duncan, Joshua J.; Youngquist, Robert C.

    2013-01-01

    The scope of this testing includes the Surface Acoustic Wave Sensor System delivered to KSC: two interrogator (transceiver) systems, four temperature sensors, with wooden mounting blocks, two antennas, two power supplies, network cables, and analysis software. Also included are a number of additional temperature sensors and newly-developed hydrogen sensors

  6. Detection of in-plane displacements of acoustic wave fields using extrinsic Fizeau fiber interferometric sensors

    NASA Technical Reports Server (NTRS)

    Dhawan, R.; Gunther, M. F.; Claus, R. O.

    1991-01-01

    Quantitative measurements of the in-plane particle displacement components of ultrasonic surface acoustic wave fields using extrinsic Fizeau fiber interferometric (EFFI) sensors are reported. Wave propagation in materials and the fiber sensor elements are briefly discussed. Calibrated experimental results obtained for simulated acoustic emission events on homogeneous metal test specimens are reported and compared to previous results obtained using piezoelectric transducers.

  7. Distributed acoustic fibre optic sensors for condition monitoring of pipelines

    NASA Astrophysics Data System (ADS)

    Hussels, Maria-Teresa; Chruscicki, Sebastian; Habib, Abdelkarim; Krebber, Katerina

    2016-05-01

    Industrial piping systems are particularly relevant to public safety and the continuous availability of infrastructure. However, condition monitoring systems based on many discrete sensors are generally not well-suited for widespread piping systems due to considerable installation effort, while use of distributed fibre-optic sensors would reduce this effort to a minimum. Specifically distributed acoustic sensing (DAS) is employed for detection of third-party threats and leaks in oil and gas pipelines in recent years and can in principle also be applied to industrial plants. Further possible detection routes amenable by DAS that could identify damage prior to emission of medium are subject of a current project at BAM, which aims at qualifying distributed fibre optic methods such as DAS as a means for spatially continuous monitoring of industrial piping systems. Here, first tests on a short pipe are presented, where optical fibres were applied directly to the surface. An artificial signal was used to define suitable parameters of the measurement system and compare different ways of applying the sensor.

  8. Acoustic emission detection with fiber optical sensors for dry cask storage health monitoring

    NASA Astrophysics Data System (ADS)

    Lin, Bin; Bao, Jingjing; Yu, Lingyu; Giurgiutiu, Victor

    2016-04-01

    The increasing number, size, and complexity of nuclear facilities deployed worldwide are increasing the need to maintain readiness and develop innovative sensing materials to monitor important to safety structures (ITS). In the past two decades, an extensive sensor technology development has been used for structural health monitoring (SHM). Technologies for the diagnosis and prognosis of a nuclear system, such as dry cask storage system (DCSS), can improve verification of the health of the structure that can eventually reduce the likelihood of inadvertently failure of a component. Fiber optical sensors have emerged as one of the major SHM technologies developed particularly for temperature and strain measurements. This paper presents the development of optical equipment that is suitable for ultrasonic guided wave detection for active SHM in the MHz range. An experimental study of using fiber Bragg grating (FBG) as acoustic emission (AE) sensors was performed on steel blocks. FBG have the advantage of being durable, lightweight, and easily embeddable into composite structures as well as being immune to electromagnetic interference and optically multiplexed. The temperature effect on the FBG sensors was also studied. A multi-channel FBG system was developed and compared with piezoelectric based AE system. The paper ends with conclusions and suggestions for further work.

  9. Marine bioacoustics and technology: The new world of marine acoustic ecology

    NASA Astrophysics Data System (ADS)

    Hastings, Mardi C.; Au, Whitlow W. L.

    2012-11-01

    Marine animals use sound for communication, navigation, predator avoidance, and prey detection. Thus the rise in acoustic energy associated with increasing human activity in the ocean has potential to impact the lives of marine animals. Thirty years ago marine bioacoustics primarily focused on evaluating effects of human-generated sound on hearing and behavior by testing captive animals and visually observing wild animals. Since that time rapidly changing electronic and computing technologies have yielded three tools that revolutionized how bioacousticians study marine animals. These tools are (1) portable systems for measuring electrophysiological auditory evoked potentials, (2) miniaturized tags equipped with positioning sensors and acoustic recording devices for continuous short-term acoustical observation rather than intermittent visual observation, and (3) passive acoustic monitoring (PAM) systems for remote long-term acoustic observations at specific locations. The beauty of these breakthroughs is their direct applicability to wild animals in natural habitats rather than only to animals held in captivity. Hearing capabilities of many wild species including polar bears, beaked whales, and reef fishes have now been assessed by measuring their auditory evoked potentials. Miniaturized acoustic tags temporarily attached to an animal to record its movements and acoustic environment have revealed the acoustic foraging behavior of sperm and beaked whales. Now tags are being adapted to fishes in effort to understand their behavior in the presence of noise. Moving and static PAM systems automatically detect and characterize biological and physical features of an ocean area without adding any acoustic energy to the environment. PAM is becoming a powerful technique for understanding and managing marine habitats. This paper will review the influence of these transformative tools on the knowledge base of marine bioacoustics and elucidation of relationships between marine

  10. Langasite Surface Acoustic Wave Gas Sensors: Modeling and Verification

    SciTech Connect

    Zheng, Peng; Greve, David W; Oppenheim, Irving J

    2013-01-01

    We report finite element simulations of the effect of conductive sensing layers on the surface wave velocity of langasite substrates. The simulations include both the mechanical and electrical influences of the conducting sensing layer. We show that three-dimensional simulations are necessary because of the out-of-plane displacements of the commonly used (0, 138.5, 26.7) Euler angle. Measurements of the transducer input admittance in reflective delay-line devices yield a value for the electromechanical coupling coefficient that is in good agreement with the three-dimensional simulations on bare langasite substrate. The input admittance measurements also show evidence of excitation of an additional wave mode and excess loss due to the finger resistance. The results of these simulations and measurements will be useful in the design of surface acoustic wave gas sensors.

  11. Enhanced directional sensitivity of a biomimetic MEMS acoustic localization sensor

    NASA Astrophysics Data System (ADS)

    Gee, Danny; Liu, Haijun; Currano, Luke; Yu, Miao

    2010-04-01

    We present an improved microfabricated sound localization sensor for unobtrusive surveillance systems inspired by the tympanic membranes of the parasitoid fly, Ormia ochracea. The device consists of two silicon diaphragms mechanically coupled by a suspended beam that amplifies the difference in time response, dependent on the incident angle of the sound source. Fabrication techniques were modified to reduce residual stresses and improve device uniformity. Enhanced acoustic cues for devices with central pivoting anchors were measured with laser Doppler vibrometry. Device responses to weak excitations demonstrated good sensitivity over environmental noise. An order of magnitude in time difference amplification was measured at 90° incident angles with a directional sensitivity of .39μs/degree. These results provide a foundation for realizing an accurate bio-inspired MEMS directional microphone.

  12. The contamination of acoustic pressure measurements by sensor oscillations

    SciTech Connect

    Surry, J.; Kezele, D.; Risley, C.

    1996-04-01

    The significance of micromotion (sensor) noise contamination of low frequency, low level, ambient ocean acoustic measurements has been pursued experimentally and analytically. Oceanographic hydrophones are subject to small motions resulting from various phenomena; the present study focussed on a pressure-sensitive hydrophone exposed to vertical oscillations. While under such imposed motion, the responses from a pressure-sensitive hydrophone and a collocated accelerometer were analyzed relative to a stationary reference hydrophone. The imposed motion was vertical, colored noise (1 to 50 Hz) of various acceleration amplitudes (10 {mu}g to 10 mg), transmitted through an elastic isolation suspension. Formation of Frequency Response Functions between the measured transducer signals, demonstrated that a three component model of the hydrophone signal predicts the response-to-motion contamination of the acoustic signal. In the lower frequency range, the vertical motion through the static head gradient generates a signal similar to the response-to-acoustic signal, while in the upper frequency range, the hydrophone responds inertially to the motion. For acceleration greater than 30 {mu}g, these components masked the laboratory ambient sound, except in a narrow frequency band where the two motion related components canceled each other. The in-water acceleration sensitivity of the hydrophone was found to be higher than the measured in-air value, apparently due to two hydrodynamic effects: water mass loading predicted by a classical added-mass term and a greatly magnifying effect from an adjacent moving body. Extrapolating the results to a deep ocean environment, the hydrophone signals would be contaminated below 5 Hz. A spectral technique is demonstrated to remove both forms of motion contamination from laboratory data. {copyright} {ital 1996 American Institute of Physics.}

  13. Sustainable coastal sensor networks: technologies and challenges

    NASA Astrophysics Data System (ADS)

    Carapezza, Edward M.; Butman, Jerry; Babb, Ivar; Bucklin, Ann

    2008-04-01

    This paper describes a distributed sensor network for a coastal maritime security system. This concept incorporates a network of small passive and active multi-phenomenological unattended sensors and shore based optical sensors to detect, classify, and track submerged threat objects approaching high value coastal assets, such as ports, harbors, residential, commercial, and military facilities and areas. The network of unattended, in-water sensors perform the initial detection, classification, and coarse tracking and then queues shore based optical laser radar sensors. These shore-based sensors perform a queued sector search to develop a refined track on the submerged threat objects that were initially detected by the unattended sensor network. Potential threat objects include swimmers, small unmanned underwater vehicles (UUV's), small submarines, and submerged barges. All of these threats have the potential to transport threat objects such as explosives, chemical, biological, radiological, and nuclear materials. Reliable systems with low false alarm rates (FAR) are proposed. Tens to hundreds of low cost passive sensors are proposed to be deployed conjunctively with several active acoustic and optical sensors in threat and facility dependant patterns to maximize the detection, tracking and classification of submerged threat objects. The integrated command and control system and novel microbial fuel cells to power these sensor networks are also described.

  14. 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

  15. An acoustic sensor for monitoring airflow in pediatric tracheostomy patients.

    PubMed

    Ruscher, Thomas; Wicks Phd, Alexandrina; Muelenaer Md, Andre

    2012-01-01

    Without proper monitoring, patients with artificial airways in the trachea are at high risk for complications or death. Despite routine maintenance of the tube, dislodged or copious mucus can obstruct the airway. Young children ( 3yrs) have difficulty tending to their own tubes and are particularly vulnerable to blockages. They require external respiratory sensors. In a hospital environment, ventilators, end-tidal CO2 monitors, thermistors, and other auxiliary equipment provide sufficient monitoring of respiration. However, outpatient monitoring methods, such as thoracic impedance and pulse oximetry, are indirect and prone to false positives. Desensitization of caregivers to frequent false alarms has been cited in medical literature as a contributing factor in cases of child death. Ultrasonic time-of-flight (TOF) is a technique used in specialized industrial applications to non-invasively measure liquid and gas flow. Two transducers are oriented at a diagonal across a flow channel. Velocity measurement is accomplished by detecting slight variations in transit time of contra-propagating acoustic signals with a directional component parallel to air flow. Due to the symmetry of acoustic pathway between sensors, velocity measurements are immune to partial fouling in the tube from mucus, saliva, and condensation. A first generation proof of concept prototype was constructed to evaluate the ultrasonic TOF technique for medical tracheostomy monitoring. After successful performance, a second generation prototype was designed with a smaller form factor and more advanced electronics. This prototype was tested and found to measure inspired volume with a root-mean-square error < 2% during initial trials. PMID:22846306

  16. NASA's present and future sensor technology developments

    NASA Technical Reports Server (NTRS)

    Rubin, B.

    1976-01-01

    NASA's overall sensing, data acquisition, and instrumentation programs are reviewed. The review shows that the trends in advanced sensor technology involve increased use of solid-state sensors, multiapplication sensors, standardized instrumentation, and miniaturized detectors. Examples are given of several new technologies, showing how improvements in sensor operational capability (such as enhanced sensitivity and spectral range) derived from these advances have resulted in relaxed spacecraft stability requirements, mission time savings, and savings in weight, size, and power. The introduction of multiapplication sensors and standardized instrumentation will result in measurement cost reduction and improved compatibility with standardized spacecraft.

  17. Acoustic Source Localization via Distributed Sensor Networks using Tera-scale Optical-Core Devices

    SciTech Connect

    Imam, Neena; Barhen, Jacob; Wardlaw, Michael

    2008-01-01

    For real-time acoustic source localization applications, one of the primary challenges is the considerable growth in computational complexity associated with the emergence of ever larger, active or passive, distributed sensor networks. The complexity of the calculations needed to achieve accurate source localization increases dramatically with the size of sensor arrays, resulting in substantial growth of computational requirements that cannot be met with standard hardware. One option to meet this challenge builds upon the emergence of digital optical-core devices. The objective of this work was to explore the implementation of key building block algorithms used in underwater source localization on an optical-core digital processing platform recently introduced by Lenslet Inc. They investigate key concepts of threat-detection algorithms such as Time Difference Of Arrival (TDOA) estimation via sensor data correlation in the time domain with the purpose of implementation on the optical-core processor. they illustrate their results with the aid of numerical simulation and actual optical hardware runs. The major accomplishments of this research, in terms of computational speedup and numerical accurcy achieved via the deployment of optical processing technology, should be of substantial interest to the acoustic signal processing community.

  18. Acoustic emission location on aluminum alloy structure by using FBG sensors and PSO method

    NASA Astrophysics Data System (ADS)

    Lu, Shizeng; Jiang, Mingshun; Sui, Qingmei; Dong, Huijun; Sai, Yaozhang; Jia, Lei

    2016-04-01

    Acoustic emission location is important for finding the structural crack and ensuring the structural safety. In this paper, an acoustic emission location method by using fiber Bragg grating (FBG) sensors and particle swarm optimization (PSO) algorithm were investigated. Four FBG sensors were used to form a sensing network to detect the acoustic emission signals. According to the signals, the quadrilateral array location equations were established. By analyzing the acoustic emission signal propagation characteristics, the solution of location equations was converted to an optimization problem. Thus, acoustic emission location can be achieved by using an improved PSO algorithm, which was realized by using the information fusion of multiple standards PSO, to solve the optimization problem. Finally, acoustic emission location system was established and verified on an aluminum alloy plate. The experimental results showed that the average location error was 0.010 m. This paper provided a reliable method for aluminum alloy structural acoustic emission location.

  19. Sensors Applications, Volume 6, Sensors in Aerospace Technology

    NASA Astrophysics Data System (ADS)

    Roeser, Hans Peter; von Schoenermark, Maria; Young, Erick T.

    2005-08-01

    This volume gives a detailed overview of the sensor systems employed in aerospace technology, such as sensors for different spectral ranges from the UV to NIR, temperature measuring, radio- and microwave detection and satellite positioning systems. Furthermore, atmospheric measurements for meteorological and deep space exploration purposes as well as land surveys and geological applications are treated in detail. The book series Sensors Applications covers the application of up-to-date sensor principles in key areas, such as process monitoring, building control, household appliances, health care, automobile, aerospace, or environmental technology. Microelectronics have become indispensable in measurement and control technology, meeting the increasing demand for sophisticated sensor systems. The series covers the growing need for comprehensive information on the wide variety of available systems and their purposes, potentials, applications and limitations.

  20. The design of a broadband ocean acoustic laboratory: detailed examination of vector sensor performance

    NASA Astrophysics Data System (ADS)

    Carpenter, Robert; Silvia, Manuel; Cray, Benjamin A.

    2006-05-01

    Acoustic vector sensors measure the acoustic pressure and three orthogonal components of the acoustic particle acceleration at a single point in space. These sensors, and arrays composed of them, have a number of advantages over traditional hydrophone arrays. This includes full azimuth/elevation angle estimation, even with a single sensor. It is of interest to see how in-water vector sensor performance matches theoretical bounds. A series of experiments designed to characterize the performance of vector sensors operating in shallow water was conducted to assess sensor mounting techniques, and evaluate the sensor's ability to measure bearing and elevation angles to a source as a function of waveform characteristics and signal-to-noise ratio.

  1. Comparison study of time reversal OFDM acoustic communication with vector and scalar sensors

    NASA Astrophysics Data System (ADS)

    Wang, Zhongkang; Zhang, Hongtao; Xie, Zhe

    2012-11-01

    To compare the performance of time reversal orthogonal frequency division multiplexing (OFDM) acoustic communication on vector and scalar sensors, the vector and scalar acoustic fields were modeled. Time reversal OFDM acoustic communication was then simulated for each sensor type. These results are compared with data from the CAPEx'09 experiment. The abilityof particle velocity channels to achieve reliable acoustic communication, as predicted by the model, is confirmed with the experiment data. Experimental results show that vector receivers can reduce the required array size, in comparisonto hydrophone arrays, whileproviding comparable communication performance.

  2. Temperature Measurements on Hot Spots of Power Substations Utilizing Surface Acoustic Wave Sensors

    NASA Astrophysics Data System (ADS)

    Cavaco, M. A. M.; Benedet, M. E.; Neto, L. R.

    2011-12-01

    In several applications in the field of metrology, the direct connection of the sensor element with the respective signal-processing unit of the measurement system is not trivial. It can be mentioned, as an example, the measurement of hot points in electric power substations because of the high electrical potential. To solve that problem, two alternatives were studied, one using active surface acoustic wave (SAW) sensors and other using passive SAW tags. For the passive sensor, a SAW radio-frequency identification (RFID) temperature detector was used. That technology is widely applied for typical transport identification (grain transportation, road traffic control), but its application in the field of metrology is innovative. The variation in temperature makes an alteration in the characteristics of the piezoelectric material of the SAW matrix, changing mostly the resonance frequency. Using SAW-RFID, the problem of measuring temperature basically is directed to the identification of the frequency of resonance of the SAW. The use of active SAW sensors has been demonstrated to be much more satisfactory for the solution of such a problem because of the limitation in the range of the passive sensors.

  3. OPTICAL FIBER SENSOR TECHNOLOGIES FOR EFFICIENT AND ECONOMICAL OIL RECOVERY

    SciTech Connect

    Anbo Wang; Kristie L. Cooper; Gary R. Pickrell

    2003-06-01

    Efficient recovery of petroleum reserves from existing oil wells has been proven to be difficult due to the lack of robust instrumentation that can accurately and reliably monitor processes in the downhole environment. Commercially available sensors for measurement of pressure, temperature, and fluid flow exhibit shortened lifetimes in the harsh downhole conditions, which are characterized by high pressures (up to 20 kpsi), temperatures up to 250 C, and exposure to chemically reactive fluids. Development of robust sensors that deliver continuous, real-time data on reservoir performance and petroleum flow pathways will facilitate application of advanced recovery technologies, including horizontal and multilateral wells. This is the final report for the four-year program ''Optical Fiber Sensor Technologies for Efficient and Economical Oil Recovery'', funded by the National Petroleum Technology Office of the U.S. Department of Energy, and performed by the Center for Photonics Technology of the Bradley Department of Electrical and Computer Engineering at Virginia Tech from October 1, 1999 to March 31, 2003. The main objective of this research program was to develop cost-effective, reliable optical fiber sensor instrumentation for real-time monitoring of various key parameters crucial to efficient and economical oil production. During the program, optical fiber sensors were demonstrated for the measurement of temperature, pressure, flow, and acoustic waves, including three successful field tests in the Chevron/Texaco oil fields in Coalinga, California, and at the world-class oil flow simulation facilities in Tulsa, Oklahoma. Research efforts included the design and fabrication of sensor probes, development of signal processing algorithms, construction of test systems, development and testing of strategies for the protection of optical fibers and sensors in the downhole environment, development of remote monitoring capabilities allowing real-time monitoring of the field

  4. Characterization monitoring & sensor technology crosscutting program

    SciTech Connect

    1996-08-01

    The purpose of the Characterization, Monitoring, and Sensor Technology Crosscutting Program (CMST-CP) is to deliver appropriate characterization, monitoring, and sensor technology (CMST) to the OFfice of Waste Management (EM-30), the Office of Environmental Restoration (EM-40), and the Office of Facility Transition and Management (EM-60).

  5. A novel sensor for monitoring acoustic cavitation. Part I: Concept, theory, and prototype development.

    PubMed

    Zeqiri, Bajram; Gélat, Pierre N; Hodnett, Mark; Lee, Nigel D

    2003-10-01

    This paper describes a new concept for an ultrasonic cavitation sensor designed specifically for monitoring acoustic emissions generated by small microbubbles when driven by an applied acoustic field. Its novel features include a hollow, open-ended, cylindrical shape, with the sensor being a right circular cylinder of height 32 mm and external diameter 38 mm. The internal diameter of the sensor is 30 mm; its inner surface is fabricated from a 110-microm layer of piezoelectrically active film whose measurement bandwidth is sufficient to enable acoustic emissions up to and beyond 10 MHz to be monitored. When in use, the sensor is immersed within the liquid test medium and high frequency (megahertz) acoustic emissions occurring within the hollow body of the sensor are monitored. In order to shield the sensor response from events occurring outside the cylinder, the outer surface of the sensor cylinder is encapsulated within a special 4-mm thick polyurethane-based cavitation shield with acoustic properties specifically developed to be minimally perturbing to the 40 kHz applied acoustic field but attenuating to ultrasound generated at megahertz frequencies (plane-wave transmission loss > 30 dB at 1 MHz). This paper introduces the rationale behind the new sensor, describing details of its construction and the materials formulation program undertaken to develop the cavitation shield. PMID:14609074

  6. Starch viscoelastic properties studied with an acoustic wave sensor.

    PubMed

    Santos, M D; Gomes, M T S R

    2014-01-01

    Gelatinization and retrogradation of starch was followed in real time with an acoustic wave sensor. This study relies on the monitorization of the frequency of oscillation of a piezoelectric quartz crystal in contact with a 2.5% emulsion of a commercial maize starch, during heating and cooling. The technique showed to be very powerful and sensitive to most of the changes described in the literature, which have been elucidated by some other techniques. The value for the temperature of gelatinization found using the sensor was confirmed by the analysis of the same starch emulsion by polarized light microscopy. Temperatures of gelatinization were found to vary with the sample heating rate, as follows: 73.5 °C at 2.0 °C/min, 66.0 °C at 1.0 °C/min, and 65.0 °C at 0.5 °C/min. Hysteresis of the studied system was evidenced by the frequency shift before heating and after cooling till the initial temperature. Analysis performed on a 1.5% emulsion of a rice starch heated at 2.0 °C/min and cooled as before, evidenced no hysteresis and showed complete reversibility, in which concerns to the series frequency of the piezoelectric quartz crystal. PMID:24274480

  7. Embedded and conventional ultrasonic sensors for monitoring acoustic emission during thermal fatigue

    NASA Astrophysics Data System (ADS)

    Trujillo, Blaine; Zagrai, Andrei

    2016-04-01

    Acoustic emission is widely used for monitoring pressure vessels, pipes, critical infrastructure, as well as land, sea and air vehicles. It is one of dominant approaches to explore material degradation under fatigue and events leading to material fracture. Addressing a recent interest in structural health monitoring of space vehicles, a need has emerged to evaluate material deterioration due to thermal fatigue during spacecraft atmospheric reentry. Thermal fatigue experiments were conducted, in which aluminum plates were subjected to localized heating and acoustic emission was monitoring by embedded and conventional acoustic emission sensors positioned at various distances from a heat source. At the same time, surface temperature of aluminum plates was monitored using an IR camera. Acoustic emission counts collected by embedded sensors were compared to counts measured with conventional acoustic emission sensors. Both types of sensors show noticeable increase of acoustic emission activity as localized heating source was applied to aluminum plates. Experimental data demonstrate correlation between temperature increase on the surface of the plates and increase in measured acoustic emission activity. It is concluded that under particular conditions, embedded piezoelectric wafer active sensors can be used for acoustic emission monitoring of thermally-induced structural degradation.

  8. Development of an Acoustic Sensor On-Line Gas Temperature Measurement in Gasifiers

    SciTech Connect

    Peter Ariessohn

    2008-06-30

    This project was awarded under U.S. Department of Energy (DOE) National Energy Technology Laboratory (NETL) Program Solicitation DE-PS26-02NT41422 and specifically addresses Technical Topical Area 2 - Gasification Technologies. The project team includes Enertechnix, Inc. as the main contractor and ConocoPhillips Company as a technical partner, who also provides access to the SG Solutions Gasification Facility (formerly Wabash River Energy Limited), host for the field-testing portion of the research. The objective of this project was to adapt acoustic pyrometer technology to make it suitable for measuring gas temperature inside a coal gasifier, to develop a prototype sensor based on this technology, and to demonstrate its performance through testing on a commercial gasifier. The project was organized in three phases, each of approximately one year duration. The first phase consisted of researching a variety of sound generation and coupling approaches suitable for use with a high pressure process, evaluation of the impact of gas composition variability on the acoustic temperature measurement approach, evaluation of the impact of suspended particles and gas properties on sound attenuation, evaluation of slagging issues and development of concepts to deal with this issue, development and testing of key prototype components to allow selection of the best approaches, and development of a conceptual design for a field prototype sensor that could be tested on an operating gasifier. The second phase consisted of designing and fabricating a series of prototype sensors, testing them in the laboratory, and developing a conceptual design for a field prototype sensor. The third phase consisted of designing and fabricating the field prototype, and testing it in the lab and in a commercial gasifier to demonstrate the ability to obtain accurate measurements of gas temperature in an operating gasifier. Following the completion of the initial 3 year project, several continuations

  9. Identification of cavitation signatures using both optical and PZT acoustic sensors

    NASA Astrophysics Data System (ADS)

    Vidakovic, M.; Armakolas, I.; Sun, T.; Carlton, J.; Grattan, K. T. V.

    2015-09-01

    This paper presents the results obtained from monitoring a simulated material cavitation process using both a fibre Bragg grating (FBG)-based acoustic sensor system developed at City University London and a commercial PZT (Piezoelectric Transducer) acoustic sensor, with an aim to identify the cavitation signatures. In the experiment, a sample metal plate with its back surface being instrumented with both sensors is positioned very close to an excitation sonotrode with a standard frequency of 19.5kHz. The data obtained from both sensors are recorded and analyzed, showing a very good agreement.

  10. Advanced Technology Development for Active Acoustic Liners

    NASA Technical Reports Server (NTRS)

    Sheplak, Mark; Cattafesta, Louis N., III; Nishida, Toshikazu; Kurdila, Andrew J.

    2001-01-01

    Objectives include: (1) Develop electro-mechanical/acoustic models of a Helmholtz resonator possessing a compliant diaphragm coupled to a piezoelectric device; (2) Design and fabricate the energy reclamation module and active Helmholtz resonator; (3) Develop and build appropriate energy reclamation/storage circuit; (4) Develop and fabricate appropriate piezoelectric shunt circuit to tune the compliance of the active Helmholtz resonator via a variable capacitor; (5) Quantify energy reclamation module efficiency in a grazing-flow plane wave tube possessing known acoustic energy input; and (6) Quantify actively tuned Helmholtz resonator performance in grazing-flow plane wave tube for a white-noise input

  11. Advancing Sensor Technology for Aerospace Propulsion

    NASA Technical Reports Server (NTRS)

    Figueroa, Fernando; Mercer, Carolyn R.

    2002-01-01

    NASA's Stennis Space Center (SSC) and Glenn Research Center (GRC) participate in the development of technologies for propulsion testing and propulsion applications in air and space transportation. Future transportation systems and the test facilities needed to develop and sustain them are becoming increasingly complex. Sensor technology is a fundamental pillar that makes possible development of complex systems that must operate in automatic mode (closed loop systems), or even in assisted-autonomous mode (highly self-sufficient systems such as planetary exploration spacecraft). Hence, a great deal of effort is dedicated to develop new sensors and related technologies to be used in research facilities, test facilities, and in vehicles and equipment. This paper describes sensor technologies being developed and in use at SSC and GRC, including new technologies in integrated health management involving sensors, components, processes, and vehicles.

  12. Sensor Technology and Performance Characteristics

    EPA Science Inventory

    The US EPA is currently involved in detailed laboratory and/or field studies involving a wide variety of low cost air quality sensors currently being made available to potential citizen scientists. These devices include sensors associated with the monitoring of nitrogen dioxide (...

  13. Unvoiced Speech Recognition Using Tissue-Conductive Acoustic Sensor

    NASA Astrophysics Data System (ADS)

    Heracleous, Panikos; Kaino, Tomomi; Saruwatari, Hiroshi; Shikano, Kiyohiro

    2006-12-01

    We present the use of stethoscope and silicon NAM (nonaudible murmur) microphones in automatic speech recognition. NAM microphones are special acoustic sensors, which are attached behind the talker's ear and can capture not only normal (audible) speech, but also very quietly uttered speech (nonaudible murmur). As a result, NAM microphones can be applied in automatic speech recognition systems when privacy is desired in human-machine communication. Moreover, NAM microphones show robustness against noise and they might be used in special systems (speech recognition, speech transform, etc.) for sound-impaired people. Using adaptation techniques and a small amount of training data, we achieved for a 20 k dictation task a[InlineEquation not available: see fulltext.] word accuracy for nonaudible murmur recognition in a clean environment. In this paper, we also investigate nonaudible murmur recognition in noisy environments and the effect of the Lombard reflex on nonaudible murmur recognition. We also propose three methods to integrate audible speech and nonaudible murmur recognition using a stethoscope NAM microphone with very promising results.

  14. Fly-ear inspired acoustic sensors for gunshot localization

    NASA Astrophysics Data System (ADS)

    Liu, Haijun; Currano, Luke; Gee, Danny; Yang, Benjamin; Yu, Miao

    2009-05-01

    The supersensitive ears of the parasitoid fly Ormia ochracea have inspired researchers to develop bio-inspired directional microphone for sound localization. Although the fly ear is optimized for localizing the narrow-band calling song of crickets at 5 kHz, experiments and simulation have shown that it can amplify directional cues for a wide frequency range. In this article, a theoretical investigation is presented to study the use of fly-ear inspired directional microphones for gunshot localization. Using an equivalent 2-DOF model of the fly ear, the time responses of the fly ear structure to a typical shock wave are obtained and the associated time delay is estimated by using cross-correlation. Both near-field and far-field scenarios are considered. The simulation shows that the fly ear can greatly amplify the time delay by ~20 times, which indicates that with an interaural distance of only 1.2 mm the fly ear is able to generate a time delay comparable to that obtained by a conventional microphone pair with a separation as large as 24 mm. Since the parameters of the fly ear structure can also be tuned for muzzle blast and other impulse stimulus, fly-ear inspired acoustic sensors offers great potential for developing portable gunshot localization systems.

  15. Fiber Optic Sensor for Acoustic Detection of Partial Discharges in Oil-Paper Insulated Electrical Systems

    PubMed Central

    Posada-Roman, Julio; Garcia-Souto, Jose A.; Rubio-Serrano, Jesus

    2012-01-01

    A fiber optic interferometric sensor with an intrinsic transducer along a length of the fiber is presented for ultrasound measurements of the acoustic emission from partial discharges inside oil-filled power apparatus. The sensor is designed for high sensitivity measurements in a harsh electromagnetic field environment, with wide temperature changes and immersion in oil. It allows enough sensitivity for the application, for which the acoustic pressure is in the range of units of Pa at a frequency of 150 kHz. In addition, the accessibility to the sensing region is guaranteed by immune fiber-optic cables and the optical phase sensor output. The sensor design is a compact and rugged coil of fiber. In addition to a complete calibration, the in-situ results show that two types of partial discharges are measured through their acoustic emissions with the sensor immersed in oil. PMID:22666058

  16. Development of High Temperature Gas Sensor Technology

    NASA Technical Reports Server (NTRS)

    Hunter, Gary W.; Chen, Liang-Yu; Neudeck, Philip G.; Knight, Dak; Liu, Chung-Chiun; Wu, Quing-Hai; Zhou, Huan-Jun

    1997-01-01

    The measurement of engine emissions is important for their monitoring and control. However, the ability to measure these emissions in-situ is limited. We are developing a family of high temperature gas sensors which are intended to operate in harsh environments such as those in an engine. The development of these sensors is based on progress in two types of technology: (1) The development of SiC-based semiconductor technology; and (2) Improvements in micromachining and microfabrication technology. These technologies are being used to develop point-contact sensors to measure gases which are important in emission control especially hydrogen, hydrocarbons, nitrogen oxides, and oxygen. The purpose of this paper is to discuss the development of this point-contact sensor technology. The detection of each type of gas involves its own challenges in the fields of materials science and fabrication technology. Of particular importance is sensor sensitivity, selectivity, and stability in long-term, high temperature operation. An overview is presented of each sensor type with an evaluation of its stage of development. It is concluded that this technology has significant potential for use in engine applications but further development is necessary.

  17. Denoising of human speech using combined acoustic and em sensor signal processing

    SciTech Connect

    Ng, L C; Burnett, G C; Holzrichter, J F; Gable, T J

    1999-11-29

    Low Power EM radar-like sensors have made it possible to measure properties of the human speech production system in real-time, without acoustic interference. This greatly enhances the quality and quantify of information for many speech related applications. See Holzrichter, Burnett, Ng, and Lea, J. Acoustic. Soc. Am. 103 (1) 622 (1998). By using combined Glottal-EM- Sensor- and Acoustic-signals, segments of voiced, unvoiced, and no-speech can be reliably defined. Real-time Denoising filters can be constructed to remove noise from the user's corresponding speech signal.

  18. Acoustic vector sensor beamforming reduces masking from underwater industrial noise during passive monitoring.

    PubMed

    Thode, Aaron M; Kim, Katherine H; Norman, Robert G; Blackwell, Susanna B; Greene, Charles R

    2016-04-01

    Masking from industrial noise can hamper the ability to detect marine mammal sounds near industrial operations, whenever conventional (pressure sensor) hydrophones are used for passive acoustic monitoring. Using data collected from an autonomous recorder with directional capabilities (Directional Autonomous Seafloor Acoustic Recorder), deployed 4.1 km from an arctic drilling site in 2012, the authors demonstrate how conventional beamforming on an acoustic vector sensor can be used to suppress noise arriving from a narrow sector of geographic azimuths. Improvements in signal-to-noise ratio of up to 15 dB are demonstrated on bowhead whale calls, which were otherwise undetectable using conventional hydrophones. PMID:27106345

  19. A Fibre Bragg Grating Sensor as a Receiver for Acoustic Communications Signals

    PubMed Central

    Wild, Graham; Hinckley, Steven

    2011-01-01

    A Fibre Bragg Grating (FBG) acoustic sensor is used as a receiver for acoustic communications signals. Acoustic transmissions were generated in aluminium and Carbon Fibre Composite (CFC) panels. The FBG receiver was coupled to the bottom surface opposite a piezoelectric transmitter. For the CFC, a second FBG was embedded within the layup for comparison. We show the transfer function, frequency response, and transient response of the acoustic communications channels. In addition, the FBG receiver was used to detect Phase Shift Keying (PSK) communications signals, which was shown to be the most robust method in a highly resonant communications channel. PMID:22346585

  20. 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).

  1. 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.

  2. Advanced monolithic pixel sensors using SOI technology

    NASA Astrophysics Data System (ADS)

    Miyoshi, Toshinobu; Arai, Yasuo; Asano, Mari; Fujita, Yowichi; Hamasaki, Ryutaro; Hara, Kazuhiko; Honda, Shunsuke; Ikegami, Yoichi; Kurachi, Ikuo; Mitsui, Shingo; Nishimura, Ryutaro; Tauchi, Kazuya; Tobita, Naoshi; Tsuboyama, Toru; Yamada, Miho

    2016-07-01

    We are developing advanced pixel sensors using silicon-on-insulator (SOI) technology. A SOI wafer is used; top silicon is used for electric circuit and bottom silicon is used as a sensor. Target applications are high-energy physics, X-ray astronomy, material science, non-destructive inspection, medical application and so on. We have developed two integration-type pixel sensors, FPIXb and INTPIX7. These sensors were processed on single SOI wafers with various substrates in n- or p-type and double SOI wafers. The development status of double SOI sensors and some up-to-date test results of n-type and p-type SOI sensors are shown.

  3. Health-Enabled Smart Sensor Fusion Technology

    NASA Technical Reports Server (NTRS)

    Wang, Ray

    2012-01-01

    A process was designed to fuse data from multiple sensors in order to make a more accurate estimation of the environment and overall health in an intelligent rocket test facility (IRTF), to provide reliable, high-confidence measurements for a variety of propulsion test articles. The object of the technology is to provide sensor fusion based on a distributed architecture. Specifically, the fusion technology is intended to succeed in providing health condition monitoring capability at the intelligent transceiver, such as RF signal strength, battery reading, computing resource monitoring, and sensor data reading. The technology also provides analytic and diagnostic intelligence at the intelligent transceiver, enhancing the IEEE 1451.x-based standard for sensor data management and distributions, as well as providing appropriate communications protocols to enable complex interactions to support timely and high-quality flow of information among the system elements.

  4. Tracking a convoy of multiple targets using acoustic sensor data

    NASA Astrophysics Data System (ADS)

    Damarla, T. R.

    2003-08-01

    In this paper we present an algorithm to track a convoy of several targets in a scene using acoustic sensor array data. The tracking algorithm is based on template of the direction of arrival (DOA) angles for the leading target. Often the first target is the closest target to the sensor array and hence the loudest with good signal to noise ratio. Several steps were used to generate a template of the DOA angle for the leading target, namely, (a) the angle at the present instant should be close to the angle at the previous instant and (b) the angle at the present instant should be within error bounds of the predicted value based on the previous values. Once the template of the DOA angles of the leading target is developed, it is used to predict the DOA angle tracks of the remaining targets. In order to generate the tracks for the remaining targets, a track is established if the angles correspond to the initial track values of the first target. Second the time delay between the first track and the remaining tracks are estimated at the highest correlation points between the first track and the remaining tracks. As the vehicles move at different speeds the tracks either compress or expand depending on whether a target is moving fast or slow compared to the first target. The expansion and compression ratios are estimated and used to estimate the predicted DOA angle values of the remaining targets. Based on these predicted DOA angles of the remaining targets the DOA angles obtained from the MVDR or Incoherent MUSIC will be appropriately assigned to proper tracks. Several other rules were developed to avoid mixing the tracks. The algorithm is tested on data collected at Aberdeen Proving Ground with a convoy of 3, 4 and 5 vehicles. Some of the vehicles are tracked and some are wheeled vehicles. The tracking algorithm results are found to be good. The results will be presented at the conference and in the paper.

  5. Probing mechanical properties of liposomes using acoustic sensors.

    PubMed

    Melzak, Kathryn A; Bender, Florian; Tsortos, Achilleas; Gizeli, Electra

    2008-08-19

    Acoustic devices were employed to characterize variations in the mechanical properties (density and viscoelasticity) of liposomes composed of 1-oleoyl-2-palmitoyl- sn-glycero-3-phosphocholine (POPC) and cholesterol. Liposome properties were modified in three ways. In some experiments, the POPC/cholesterol ratio was varied prior to deposition on the device surface. Alternatively, the ratio was changed in situ via either insertion of cholesterol or removal of cholesterol with beta-cyclodextrin. This was done for liposomes adsorbed directly on the device surface and for liposomes attached via a biotin-terminated poly(ethylene glycol) linker. The acoustic measurements make use of two simultaneous time-resolved signals: one signal is related to the velocity of the acoustic wave, while the second is related to dissipation of acoustic energy. Together, they provide information not only about the mass (or density) of the probed medium but also about its viscoelastic properties. The cholesterol-induced increase in the surface density of the lipid bilayer was indeed observed in the acoustic data, but the resulting change in signal was larger than expected from the change in surface density. In addition, increasing the bilayer resistance to stretching was found to lead to a greater dissipation of the acoustic energy. The acoustic response is assessed in terms of the possible distortions of the liposomes and the known effects of cholesterol on the mechanical properties of the lipid bilayer that encloses the aqueous core of the liposome. To aid the interpretation of the acoustic response, it is discussed how the above changes in the lipid bilayer will affect the effective viscoelastic properties of the entire liposome/solvent film on the scale of the acoustic wavelength. It was found that the acoustic device is very sensitive to the mechanical properties of lipid vesicles; the response of the acoustic device is explained, and the basic underlying mechanisms of interaction are

  6. Acoustic Doppler velocity measurement system using capacitive micromachined ultrasound transducer array technology.

    PubMed

    Shin, Minchul; Krause, Joshua S; DeBitetto, Paul; White, Robert D

    2013-08-01

    This paper describes the design, fabrication, modeling, and characterization of a small (1 cm(2) transducer chip) acoustic Doppler velocity measurement system using microelectromechanical systems capacitive micromachined ultrasound transducer (cMUT) array technology. The cMUT sensor has a 185 kHz resonant frequency to achieve a 13° beam width for a 1 cm aperture. A model for the cMUT and the acoustic system which includes electrical, mechanical, and acoustic components is provided. Furthermore, this paper shows characterization of the cMUT sensor with a variety of testing procedures including Laser Doppler Vibrometry (LDV), beampattern measurement, reflection testing, and velocity testing. LDV measurements demonstrate that the membrane displacement at the center point is 0.4 nm/V(2) at 185 kHz. The maximum range of the sensor is 60 cm (30 cm out and 30 cm back). A velocity sled was constructed and used to demonstrate measureable Doppler shifts at velocities from 0.2 to 1.0 m/s. The Doppler shifts agree well with the expected frequency shifts over this range. PMID:23927100

  7. Optical waveguide tamper sensor technology

    SciTech Connect

    Carson, R.F.; Butler, M.A.; Sinclair, M.B.

    1997-03-01

    Dielectric optical waveguides exhibit properties that are well suited to sensor applications. They have low refractive index and are transparent to a wide range of wavelengths. They can react with the surrounding environment in a variety of controllable ways. In certain sensor applications, it is advantageous to integrate the dielectric waveguide on a semiconductor substrate with active devices. In this work, we demonstrate a tamper sensor based on dielectric waveguides that connect epitaxial GaAs-GaAlAs sources and detectors. The tamper sensing function is realized by attaching particles of absorbing material with high refractive index to the surface of the waveguides. These absorbers are then attached to a lid or cover, as in an integrated circuit package or multi-chip module. The absorbers attenuate the light in the waveguides as a function of absorber interaction. In the tamper indicating mode, the absorbers are placed randomly on the waveguides, to form a unique attenuation pattern that is registered by the relative signal levels on the photodetectors. When the lid is moved, the pattern of absorbers changes, altering the photodetector signals. This dielectric waveguide arrangement is applicable to a variety of sensor functions, and specifically can be fabricated as a chemical sensor by the application of cladding layers that change their refractive index and/or optical absorption properties upon exposure to selected chemical species. An example is found in palladium claddings that are sensitive to hydrogen. A description of designs and a basic demonstration of the tamper sensing and chemical sensing functions is described herein.

  8. Applying Sensor Web Technology to Marine Sensor Data

    NASA Astrophysics Data System (ADS)

    Jirka, Simon; del Rio, Joaquin; Mihai Toma, Daniel; Nüst, Daniel; Stasch, Christoph; Delory, Eric

    2015-04-01

    In this contribution we present two activities illustrating how Sensor Web technology helps to enable a flexible and interoperable sharing of marine observation data based on standards. An important foundation is the Sensor Web Architecture developed by the European FP7 project NeXOS (Next generation Low-Cost Multifunctional Web Enabled Ocean Sensor Systems Empowering Marine, Maritime and Fisheries Management). This architecture relies on the Open Geospatial Consortium's (OGC) Sensor Web Enablement (SWE) framework. It is an exemplary solution for facilitating the interoperable exchange of marine observation data within and between (research) organisations. The architecture addresses a series of functional and non-functional requirements which are fulfilled through different types of OGC SWE components. The diverse functionalities offered by the NeXOS Sensor Web architecture are shown in the following overview: - Pull-based observation data download: This is achieved through the OGC Sensor Observation Service (SOS) 2.0 interface standard. - Push-based delivery of observation data to allow users the subscription to new measurements that are relevant for them: For this purpose there are currently several specification activities under evaluation (e.g. OGC Sensor Event Service, OGC Publish/Subscribe Standards Working Group). - (Web-based) visualisation of marine observation data: Implemented through SOS client applications. - Configuration and controlling of sensor devices: This is ensured through the OGC Sensor Planning Service 2.0 interface. - Bridging between sensors/data loggers and Sensor Web components: For this purpose several components such as the "Smart Electronic Interface for Sensor Interoperability" (SEISI) concept are developed; this is complemented by a more lightweight SOS extension (e.g. based on the W3C Efficient XML Interchange (EXI) format). To further advance this architecture, there is on-going work to develop dedicated profiles of selected OGC

  9. The Savannah River Technology Center, a leader in sensor technology

    SciTech Connect

    Stewart, W.C.

    1993-12-01

    This publication highlights the capabilities and achievements of the Savannah River Technology Center in the field of sensor technology. Sensors are developed to provide solutions for environmental and chemical analysis. Most of their sensor systems are based upon fiber optics. Fiber optic probes function in three main modes: as a reflected light probe, from opaque samples; as a transreflectance probe, which sample light reflected back from samples which can pass light; and a flow cell, which monitors light transmitted through a path which passes the process stream being tested. The sensor group has developed fiber optic based temperature probes, has combined fiber optics with sol-gel technology to monitor process streams using chemical indicators, has done development work on slip stream on-line sampling of chemical process streams, has developed software to aid in the analysis of chemical solutions, and has applied this technology in a wide range of emerging areas.

  10. Multi Reflection of Lamb Wave Emission in an Acoustic Waveguide Sensor

    PubMed Central

    Schmitt, Martin; Olfert, Sergei; Rautenberg, Jens; Lindner, Gerhard; Henning, Bernd; Reindl, Leonhard Michael

    2013-01-01

    Recently, an acoustic waveguide sensor based on multiple mode conversion of surface acoustic waves at the solid—liquid interfaces has been introduced for the concentration measurement of binary and ternary mixtures, liquid level sensing, investigation of spatial inhomogenities or bubble detection. In this contribution the sound wave propagation within this acoustic waveguide sensor is visualized by Schlieren imaging for continuous and burst operation the first time. In the acoustic waveguide the antisymmetrical zero order Lamb wave mode is excited by a single phase transducer of 1 MHz on thin glass plates of 1 mm thickness. By contact to the investigated liquid Lamb waves propagating on the first plate emit pressure waves into the adjacent liquid, which excites Lamb waves on the second plate, what again causes pressure waves traveling inside the liquid back to the first plate and so on. The Schlieren images prove this multi reflection within the acoustic waveguide, which confirms former considerations and calculations based on the receiver signal. With this knowledge the sensor concepts with the acoustic waveguide sensor can be interpreted in a better manner. PMID:23447010

  11. Distributed Acoustic Sensing Technology in a Magmatic Geothermal Field - First Results From a Survey in Iceland

    NASA Astrophysics Data System (ADS)

    Reinsch, Thomas; Jousset, Philippe; Henninges, Jan; Blanck, Hanna

    2016-04-01

    Seismic methods are particularly suited for investigating the Earth's subsurface. Compared to surface-measurements , wellbore measurements can be used to acquire more detailed information about rock properties and possible fluid pathways within a geothermal reservoir. For high temperature geothermal wells, however, ambient temperatures are often far above the operating temperature range of conventional geophones. One way to overcome this limitation is the application of fiber optic sensor systems, where only the passive optical fiber is subjected to downhole conditions. Their applicability is thus determined by the operating temperature range of the optical fiber. Choosing appropriate fibers, such sensor systems can be operated at temperatures far above 200°C. Along an optical fiber, the distributed acoustic sensing technology (DAS) can be used to acquire acoustic signals with a high spatial and temporal resolution. Previous experiments have shown that the DAS technology is well suited for active seismic measurements. Within the framework of the EC funded project IMAGE, a fiber optic cable was deployed in a newly drilled geothermal well (RN-34) within the Reykjanes geothermal field, Iceland. Additionally, a >15 km fiber optic cable, already available at the surface, was connected to a DAS read-out unit. Acoustic data was acquired continuously for 9 days. Hammer shots were performed at the wellhead as well as along the surface cable in order to locate individual acoustic traces and calibrate the spatial distribution of the acoustic information. During the monitoring period both signals from on- and offshore explosive sources and natural seismic events could be recorded. We compare the fiber optic data to conventional seismic records from a dense seismic network deployed on the Reykjanes in the course of the IMAGE project. Here, first results from the seismic survey will be presented.

  12. Energy Efficient Engine acoustic supporting technology report

    NASA Technical Reports Server (NTRS)

    Lavin, S. P.; Ho, P. Y.

    1985-01-01

    The acoustic development of the Energy Efficient Engine combined testing and analysis using scale model rigs and an integrated Core/Low Spool demonstration engine. The scale model tests show that a cut-on blade/vane ratio fan with a large spacing (S/C = 2.3) is as quiet as a cut-off blade/vane ratio with a tighter spacing (S/C = 1.27). Scale model mixer tests show that separate flow nozzles are the noisiest, conic nozzles the quietest, with forced mixers in between. Based on projections of ICLS data the Energy Efficient Engine (E3) has FAR 36 margins of 3.7 EPNdB at approach, 4.5 EPNdB at full power takeoff, and 7.2 EPNdB at sideline conditions.

  13. Acoustic emission technology for space applications

    SciTech Connect

    Friesel, M.A.; Lemon, D.K.; Skorpik, J.R.; Hutton, P.H.

    1989-05-01

    Clearly the structural and functional integrity of space station components is a primary requirement. The combinations of advanced materials, new designs, and an unusual environment increase the need for inservice monitoring to help assure component integrity. Continuous monitoring of the components using acoustic emission (AE) methods can provide early indication of structural or functional distress, thus allowing time to plan remedial action. The term ''AE'' refers to energy impulses propagated from a growing crack in a solid material or from a leak in a pressurized pipe or tube. In addition to detecting a crack or leak, AE methods can provide information on the location of the defect and an estimate of crack growth rate and leak rate. 8 figs.

  14. Enhanced technologies for unattended ground sensor systems

    NASA Astrophysics Data System (ADS)

    Hartup, David C.

    2010-04-01

    Progress in several technical areas is being leveraged to advantage in Unattended Ground Sensor (UGS) systems. This paper discusses advanced technologies that are appropriate for use in UGS systems. While some technologies provide evolutionary improvements, other technologies result in revolutionary performance advancements for UGS systems. Some specific technologies discussed include wireless cameras and viewers, commercial PDA-based system programmers and monitors, new materials and techniques for packaging improvements, low power cueing sensor radios, advanced long-haul terrestrial and SATCOM radios, and networked communications. Other technologies covered include advanced target detection algorithms, high pixel count cameras for license plate and facial recognition, small cameras that provide large stand-off distances, video transmissions of target activity instead of still images, sensor fusion algorithms, and control center hardware. The impact of each technology on the overall UGS system architecture is discussed, along with the advantages provided to UGS system users. Areas of analysis include required camera parameters as a function of stand-off distance for license plate and facial recognition applications, power consumption for wireless cameras and viewers, sensor fusion communication requirements, and requirements to practically implement video transmission through UGS systems. Examples of devices that have already been fielded using technology from several of these areas are given.

  15. Study on high temperature Fabry-Perot fiber acoustic sensor with temperature self-compensation

    NASA Astrophysics Data System (ADS)

    Hu, Pan; Tong, Xinglin; Zhao, Minli; Deng, Chengwei; Guo, Qian; Mao, Yan; Wang, Kun

    2015-09-01

    A Fabry-Perot (F-P) fiber acoustic sensor, which can work under high-temperature harsh environment with temperature self-compensation, is designed and prepared. A condenser was used to maintain the sensor to work in a stable temperature environment. Because of the special structure of the sensor and the function of the condenser, the cavity variation of the sensor caused by changes of external temperature from -10°C to 500°C would not exceed 8 nm. The experimental results show that the sensor has a good frequency response in a range of 1 to 5 kHz and the field experiment results show that it could be used for hydraulic decoking online monitoring by judging the acoustic frequency spectrum.

  16. Flexible sensors for biomedical technology.

    PubMed

    Vilela, Diana; Romeo, Agostino; Sánchez, Samuel

    2016-02-01

    Flexible sensing devices have gained a great deal of attention among the scientific community in recent years. The application of flexible sensors spans over several fields, including medicine, industrial automation, robotics, security, and human-machine interfacing. In particular, non-invasive health-monitoring devices are expected to play a key role in the improvement of patient life and in reducing costs associated with clinical and biomedical diagnostic procedures. Here, we focus on recent advances achieved in flexible devices applied on the human skin for biomedical and healthcare purposes. PMID:26675174

  17. Distributed feedback fiber laser acoustic emission sensor for concrete structure health monitoring

    NASA Astrophysics Data System (ADS)

    Hao, Gengjie; Huang, Wenzhu; Zhang, Wentao; Sun, Baochen; Li, Fang

    2014-05-01

    This paper introduces a highly-sensitive fiber optical acoustic emission (AE) sensor and a parameter analysis method aiming at concrete structure health monitoring. Distributed feedback fiber-laser (DFB-FL), which is encapsulated to have a high acoustic sensitivity, is used for sensor unit of the AE sensor. The AE signal of concrete beam in different work stages, based on the four-point bending experiment of the concrete beam, is picked up, and the relationship between the concrete beam work stages and the AE parameter is found. The results indicate that DFB-FLAES can be used as sensitive transducers for recording acoustic events and forecasting the imminent failure of the concrete beam.

  18. Characterization, Monitoring and Sensor Technology Integrated Program

    SciTech Connect

    Not Available

    1993-04-01

    This booklet contains summary sheets that describe FY 1993 characterization, monitoring, and sensor technology (CMST) development projects. Currently, 32 projects are funded, 22 through the OTD Characterization, Monitoring, and Sensor Technology Integrated Program (CMST-IP), 8 through the OTD Program Research and Development Announcement (PRDA) activity managed by the Morgantown Energy Technology Center (METC), and 2 through Interagency Agreements (IAGs). This booklet is not inclusive of those CMST projects which are funded through Integrated Demonstrations (IDs) and other Integrated Programs (IPs). The projects are in six areas: Expedited Site Characterization; Contaminants in Soils and Groundwater; Geophysical and Hydrogeological Measurements; Mixed Wastes in Drums, Burial Grounds, and USTs; Remediation, D&D, and Waste Process Monitoring; and Performance Specifications and Program Support. A task description, technology needs, accomplishments and technology transfer information is given for each project.

  19. Novel EO/IR sensor technologies

    NASA Astrophysics Data System (ADS)

    Lewis, Keith

    2011-10-01

    The requirements for advanced EO/IR sensor technologies are discussed in the context of evolving military operations, with significant emphasis on the development of new sensing technologies to meet the challenges posed by asymmetric threats. The Electro-Magnetic Remote Sensing (EMRS DTC) was established in 2003 to provide a centre of excellence in sensor research and development, supporting new capabilities in key military areas such as precision attack, battlespace manoeuvre and information superiority. In the area of advanced electro-optic technology, the DTC has supported work on discriminative imaging, advanced detectors, laser components/technologies, and novel optical techniques. This paper provides a summary of some of the EO/IR technologies explored by the DTC.

  20. Dual output acoustic wave sensor for molecular identification

    SciTech Connect

    Frye, G.C.; Martin, S.J.

    1990-10-03

    The invention comprises a method for the identification and quantification of sorbed chemical species onto a coating of a device capable of generating and receiving an acoustic wave, by measuring the changes in the velocity of the acoustic wave resulting from the sorption of the chemical species into the coating as the wave travels through the coating and by measuring the changes in the attenuation of an acoustic wave resulting from the sorption of the chemical species into the coating as the wave travels through the coating. The inventive method further correlates the magnitudes of the changes of velocity with respect to changes of the attenuation of the acoustic wave to identify the sorbed chemical species. The absolute magnitudes of the velocity changes or the absolute magnitude of the attenuation changes are used to determine the concentration of the identified chemical species.

  1. Graph-based sensor fusion for classification of transient acoustic signals.

    PubMed

    Srinivas, Umamahesh; Nasrabadi, Nasser M; Monga, Vishal

    2015-03-01

    Advances in acoustic sensing have enabled the simultaneous acquisition of multiple measurements of the same physical event via co-located acoustic sensors. We exploit the inherent correlation among such multiple measurements for acoustic signal classification, to identify the launch/impact of munition (i.e., rockets, mortars). Specifically, we propose a probabilistic graphical model framework that can explicitly learn the class conditional correlations between the cepstral features extracted from these different measurements. Additionally, we employ symbolic dynamic filtering-based features, which offer improvements over the traditional cepstral features in terms of robustness to signal distortions. Experiments on real acoustic data sets show that our proposed algorithm outperforms conventional classifiers as well as the recently proposed joint sparsity models for multisensor acoustic classification. Additionally our proposed algorithm is less sensitive to insufficiency in training samples compared to competing approaches. PMID:25014986

  2. Modal structural acoustic sensing with minimum number of optimally placed piezoelectric sensors

    NASA Astrophysics Data System (ADS)

    Loghmani, Ali; Danesh, Mohammad; Keshmiri, Mehdi

    2016-02-01

    Structural acoustic sensing is a method of obtaining radiated sound pressure from a vibrating structure using vibration information. Structural acoustic sensing is used in active structural acoustic control for attenuating the sound radiated from a structure. In this paper, a new approach called Modal Structural Acoustic Sensing (MSAS) is proposed for estimating the pressure radiated from a vibrating cylindrical shell using piezoelectric sensors. The motion equations of a cylindrical shell in conjunction with piezoelectric patches are derived based on the Donnel-Mushtari shell theory. The locations of the piezoelectric sensors are optimized by the Genetic Algorithm based on maximizing the observability gramian matrix. The Kirchhoff-Helmholtz integral is used for estimating the sound pressure radiated from the cylindrical shell. Numerical simulations are performed to demonstrate the advantages of the proposed approach in comparison with previous methods such as discrete structural acoustic sensing and distributed modal sensors. Results show that the MSAS can increase the estimation accuracy and decrease the controller dimensionality and the number of required sensors.

  3. Nanolitre-scale crystallization using acoustic liquid-transfer technology

    PubMed Central

    Villaseñor, Armando G.; Wong, April; Shao, Ada; Garg, Ankur; Donohue, Timothy J.; Kuglstatter, Andreas; Harris, Seth F.

    2012-01-01

    Focused acoustic energy allows accurate and precise liquid transfer on scales from picolitre to microlitre volumes. This technology was applied in protein crystallization, successfully transferring a diverse set of proteins as well as hundreds of precipitant solutions from custom and commercial crystallization screens and achieving crystallization in drop volumes as small as 20 nl. Only higher concentrations (>50%) of 2-­methyl-2,4-pentanediol (MPD) appeared to be systematically problematic in delivery. The acoustic technology was implemented in a workflow, successfully reproducing active crystallization systems and leading to the discovery of crystallization conditions for previously uncharacterized proteins. The technology offers compelling advantages in low-nanolitre crystallization trials by providing significant reagent savings and presenting seamless scalability for those crystals that require larger volume optimization experiments using the same vapor-diffusion format. PMID:22868754

  4. Photo sensor array technology development

    NASA Technical Reports Server (NTRS)

    Rossman, M. W.; Young, V. F.; Beall, J. R.

    1977-01-01

    The development of an improved capability photo sensor array imager for use in a Viking '75 type facsimile camera is presented. This imager consists of silicon photodiodes and lead sulfide detectors to cover a spectral range from 0.4 to 2.7 microns. An optical design specifying filter configurations and convergence angles is described. Three electronics design approaches: AC-chopped light, DC-dual detector, and DC-single detector, are investigated. Experimental and calculated results are compared whenever possible using breadboard testing and tolerance analysis techniques. Results show that any design used must be forgiving of the relative instability of lead sulfide detectors. A final design using lead sulfide detectors and associated electronics is implemented by fabrication of a hybrid prototype device. Test results of this device show a good agreement with calculated values.

  5. Acoustic ranging of small arms fire using a single sensor node collocated with the target.

    PubMed

    Lo, Kam W; Ferguson, Brian G

    2015-06-01

    A ballistic model-based method, which builds upon previous work by Lo and Ferguson [J. Acoust. Soc. Am. 132, 2997-3017 (2012)], is described for ranging small arms fire using a single acoustic sensor node collocated with the target, without a priori knowledge of the muzzle speed and ballistic constant of the bullet except that they belong to a known two-dimensional parameter space. The method requires measurements of the differential time of arrival and differential angle of arrival of the muzzle blast and ballistic shock wave at the sensor node. Its performance is evaluated using both simulated and real data. PMID:26093450

  6. Acoustic and optical multi-sensor threat detection system for border patrol against aerial threats

    NASA Astrophysics Data System (ADS)

    Alsawadi, Motasem S.; Ismail, Ahmad; Al-Azem, Badeea F.; El-Desouki, Munir M.; Alghamdi, Sultan; Alghamdi, Mansour

    2012-10-01

    Saudi Arabia has borders covering over 4,300 km that are shared with seven countries. Such large borders pose many challenges for security and patrol. Thermal imagers are considered the most reliable means of threat detection, however, they are quite costly, which can prevent using them over large areas. This work discusses a multi-sensor acoustic and optical implementation for threat detection as an effort to reduce system cost. The acoustic sensor provides position and direction recognition by using a four microphone setup. The data analysis of field tests will be discussed in this work.

  7. A hybrid path-oriented code assignment CDMA-based MAC protocol for underwater acoustic sensor networks.

    PubMed

    Chen, Huifang; Fan, Guangyu; Xie, Lei; Cui, Jun-Hong

    2013-01-01

    Due to the characteristics of underwater acoustic channel, media access control (MAC) protocols designed for underwater acoustic sensor networks (UWASNs) are quite different from those for terrestrial wireless sensor networks. Moreover, in a sink-oriented network with event information generation in a sensor field and message forwarding to the sink hop-by-hop, the sensors near the sink have to transmit more packets than those far from the sink, and then a funneling effect occurs, which leads to packet congestion, collisions and losses, especially in UWASNs with long propagation delays. An improved CDMA-based MAC protocol, named path-oriented code assignment (POCA) CDMA MAC (POCA-CDMA-MAC), is proposed for UWASNs in this paper. In the proposed MAC protocol, both the round-robin method and CDMA technology are adopted to make the sink receive packets from multiple paths simultaneously. Since the number of paths for information gathering is much less than that of nodes, the length of the spreading code used in the POCA-CDMA-MAC protocol is shorter greatly than that used in the CDMA-based protocols with transmitter-oriented code assignment (TOCA) or receiver-oriented code assignment (ROCA). Simulation results show that the proposed POCA-CDMA-MAC protocol achieves a higher network throughput and a lower end-to-end delay compared to other CDMA-based MAC protocols. PMID:24193100

  8. The Potential for Quantum Technology Gravity Sensors

    NASA Astrophysics Data System (ADS)

    Boddice, Daniel; Metje, Nicole; Tuckwell, George

    2016-04-01

    Gravity measurements are widely used in geophysics for the detection of subsurface cavities such as sinkhole and past mine workings. The chief advantage of gravity compared to other geophysical techniques is that it is passive method which cannot be shielded by intervening features or ground giving it no theoretical limitations on penetration depth beyond the resolution of the instrument, and that it responds to an absence of mass as opposed to a proxy ground property like other techniques. However, current instruments are limited both by their resolution and by sources of environmental noise. This can be overcome with the imminent arrival of gravity sensors using quantum technology (QT) currently developed and constructed by the QT-Hub in Sensors and Metrology, which promise a far greater resolution. The QT sensor uses a technique called atom interferometry, where cold atoms are used as ideal test-masses to create a gravity sensor which can measure a gravity gradient rather than an absolute value. This suppresses several noise sources and creates a sensor useful in everyday applications. The paper will present computer simulations of buried targets and noise sources to explore the potential uses of these new sensors for a range of applications including pipes, tunnels and mine shafts. This will provide information on the required resolution and sensitivity of any new sensor if it is to deliver the promised step change in geophysical detection capability.

  9. 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.

  10. Throughput and Energy Efficiency of a Cooperative Hybrid ARQ Protocol for Underwater Acoustic Sensor Networks

    PubMed Central

    Ghosh, Arindam; Lee, Jae-Won; Cho, Ho-Shin

    2013-01-01

    Due to its efficiency, reliability and better channel and resource utilization, cooperative transmission technologies have been attractive options in underwater as well as terrestrial sensor networks. Their performance can be further improved if merged with forward error correction (FEC) techniques. In this paper, we propose and analyze a retransmission protocol named Cooperative-Hybrid Automatic Repeat reQuest (C-HARQ) for underwater acoustic sensor networks, which exploits both the reliability of cooperative ARQ (CARQ) and the efficiency of incremental redundancy-hybrid ARQ (IR-HARQ) using rate-compatible punctured convolution (RCPC) codes. Extensive Monte Carlo simulations are performed to investigate the performance of the protocol, in terms of both throughput and energy efficiency. The results clearly reveal the enhancement in performance achieved by the C-HARQ protocol, which outperforms both CARQ and conventional stop and wait ARQ (S&W ARQ). Further, using computer simulations, optimum values of various network parameters are estimated so as to extract the best performance out of the C-HARQ protocol. PMID:24217359

  11. Throughput and energy efficiency of a cooperative hybrid ARQ protocol for underwater acoustic sensor networks.

    PubMed

    Ghosh, Arindam; Lee, Jae-Won; Cho, Ho-Shin

    2013-01-01

    Due to its efficiency, reliability and better channel and resource utilization, cooperative transmission technologies have been attractive options in underwater as well as terrestrial sensor networks. Their performance can be further improved if merged with forward error correction (FEC) techniques. In this paper, we propose and analyze a retransmission protocol named Cooperative-Hybrid Automatic Repeat reQuest (C-HARQ) for underwater acoustic sensor networks, which exploits both the reliability of cooperative ARQ (CARQ) and the efficiency of incremental redundancy-hybrid ARQ (IR-HARQ) using rate-compatible punctured convolution (RCPC) codes. Extensive Monte Carlo simulations are performed to investigate the performance of the protocol, in terms of both throughput and energy efficiency. The results clearly reveal the enhancement in performance achieved by the C-HARQ protocol, which outperforms both CARQ and conventional stop and wait ARQ (S&W ARQ). Further, using computer simulations, optimum values of various network parameters are estimated so as to extract the best performance out of the C-HARQ protocol. PMID:24217359

  12. Acoustic emission: Standards and technology update. ASTM special technical publication 1353

    SciTech Connect

    Vahaviolos, S.J.

    1999-07-01

    The purpose of this symposium was to discuss the evolution of technology of acoustic emission (AE) over the years in instrumentation, applications, standards and codes and its overall worldwide acceptance. The papers in this conference are divided into the following sections: (1) AE Sources: Characterization; (2) Concrete Applications; (3) Integrity and Leak Detection/Location Methods; (4) AE Sensors, Standards, and Quantitative AE; (5) Diverse Industrial Applications; (6) AE Sources: Research Topics; (7) Transportation Applications, Standards, and Methodology; and (8) Compressed Gas Applications and Standards. Separate abstracts were prepared for some of the papers in this volume.

  13. Crack propagation analysis using acoustic emission sensors for structural health monitoring systems.

    PubMed

    Kral, Zachary; Horn, Walter; Steck, James

    2013-01-01

    Aerospace systems are expected to remain in service well beyond their designed life. Consequently, maintenance is an important issue. A novel method of implementing artificial neural networks and acoustic emission sensors to form a structural health monitoring (SHM) system for aerospace inspection routines was the focus of this research. Simple structural elements, consisting of flat aluminum plates of AL 2024-T3, were subjected to increasing static tensile loading. As the loading increased, designed cracks extended in length, releasing strain waves in the process. Strain wave signals, measured by acoustic emission sensors, were further analyzed in post-processing by artificial neural networks (ANN). Several experiments were performed to determine the severity and location of the crack extensions in the structure. ANNs were trained on a portion of the data acquired by the sensors and the ANNs were then validated with the remaining data. The combination of a system of acoustic emission sensors, and an ANN could determine crack extension accurately. The difference between predicted and actual crack extensions was determined to be between 0.004 in. and 0.015 in. with 95% confidence. These ANNs, coupled with acoustic emission sensors, showed promise for the creation of an SHM system for aerospace systems. PMID:24023536

  14. Crack Propagation Analysis Using Acoustic Emission Sensors for Structural Health Monitoring Systems

    DOE PAGESBeta

    Kral, Zachary; Horn, Walter; Steck, James

    2013-01-01

    Aerospace systems are expected to remain in service well beyond their designed life. Consequently, maintenance is an important issue. A novel method of implementing artificial neural networks and acoustic emission sensors to form a structural health monitoring (SHM) system for aerospace inspection routines was the focus of this research. Simple structural elements, consisting of flat aluminum plates of AL 2024-T3, were subjected to increasing static tensile loading. As the loading increased, designed cracks extended in length, releasing strain waves in the process. Strain wave signals, measured by acoustic emission sensors, were further analyzed in post-processing by artificial neural networks (ANN).more » Several experiments were performed to determine the severity and location of the crack extensions in the structure. ANNs were trained on a portion of the data acquired by the sensors and the ANNs were then validated with the remaining data. The combination of a system of acoustic emission sensors, and an ANN could determine crack extension accurately. The difference between predicted and actual crack extensions was determined to be between 0.004 in. and 0.015 in. with 95% confidence. These ANNs, coupled with acoustic emission sensors, showed promise for the creation of an SHM system for aerospace systems.« less

  15. Crack Propagation Analysis Using Acoustic Emission Sensors for Structural Health Monitoring Systems

    PubMed Central

    Horn, Walter; Steck, James

    2013-01-01

    Aerospace systems are expected to remain in service well beyond their designed life. Consequently, maintenance is an important issue. A novel method of implementing artificial neural networks and acoustic emission sensors to form a structural health monitoring (SHM) system for aerospace inspection routines was the focus of this research. Simple structural elements, consisting of flat aluminum plates of AL 2024-T3, were subjected to increasing static tensile loading. As the loading increased, designed cracks extended in length, releasing strain waves in the process. Strain wave signals, measured by acoustic emission sensors, were further analyzed in post-processing by artificial neural networks (ANN). Several experiments were performed to determine the severity and location of the crack extensions in the structure. ANNs were trained on a portion of the data acquired by the sensors and the ANNs were then validated with the remaining data. The combination of a system of acoustic emission sensors, and an ANN could determine crack extension accurately. The difference between predicted and actual crack extensions was determined to be between 0.004 in. and 0.015 in. with 95% confidence. These ANNs, coupled with acoustic emission sensors, showed promise for the creation of an SHM system for aerospace systems. PMID:24023536

  16. Acoustic intensity methods and their applications to vector sensor use and design

    NASA Astrophysics Data System (ADS)

    Naluai, Nathan Kahikina

    Applications of acoustic intensity processing methods to vector sensor output signals are investigated for three specific cases: acoustic intensity scattering, spatial correlations of intensities, and conceptual design of a high frequency inertial vector sensor with a novel suspension. An overview of intensity processing is presented and the concept of a complex intensity is illustrated. Measurement techniques for determining the complex intensity spectra from the signals received by a standard acoustic vector sensor are demonstrated. Acoustic intensity processing of signals from SSQ-53D sonobuoys is used to enhance the detection of submerged bodies in bi-static sonar applications. Deep water experiments conducted at Lake Pend Oreille in northern Idaho are described. A submerged body is located between a source and a number of SSQ-53D sonobuoy receivers. Scalar pressure measurements change by less than 0.5 dB when the scattering body is inserted in the field. The phase of the orthogonal intensity component shows repeatable and strong variations of nearly 55°. The classical solution for the spatial correlation of the pressure field is presented. The derivation techniques are expanded to derive previously unsolved analytic forms for the spatial correlations of separated intensity field components based on combinations of the solutions for various pressure and velocity components. Experimental validation of these correlation solutions are performed computationally and in an underwater environment. The computational experiments are designed to test highly controlled variations to the idealized case (e.g. sound field content, transducer phasing issues, additive output noise, etc.) Additional verification is provided from physical tests measuring the correlations between a pair of acoustic vector sensors in a large reverberant tank which is excited acoustically with broadband noise. The results successfully corroborate the derivation methods for correlations of

  17. Autonomous vision networking: miniature wireless sensor networks with imaging technology

    NASA Astrophysics Data System (ADS)

    Messinger, Gioia; Goldberg, Giora

    2006-09-01

    The recent emergence of integrated PicoRadio technology, the rise of low power, low cost, System-On-Chip (SOC) CMOS imagers, coupled with the fast evolution of networking protocols and digital signal processing (DSP), created a unique opportunity to achieve the goal of deploying large-scale, low cost, intelligent, ultra-low power distributed wireless sensor networks for the visualization of the environment. Of all sensors, vision is the most desired, but its applications in distributed sensor networks have been elusive so far. Not any more. The practicality and viability of ultra-low power vision networking has been proven and its applications are countless, from security, and chemical analysis to industrial monitoring, asset tracking and visual recognition, vision networking represents a truly disruptive technology applicable to many industries. The presentation discusses some of the critical components and technologies necessary to make these networks and products affordable and ubiquitous - specifically PicoRadios, CMOS imagers, imaging DSP, networking and overall wireless sensor network (WSN) system concepts. The paradigm shift, from large, centralized and expensive sensor platforms, to small, low cost, distributed, sensor networks, is possible due to the emergence and convergence of a few innovative technologies. Avaak has developed a vision network that is aided by other sensors such as motion, acoustic and magnetic, and plans to deploy it for use in military and commercial applications. In comparison to other sensors, imagers produce large data files that require pre-processing and a certain level of compression before these are transmitted to a network server, in order to minimize the load on the network. Some of the most innovative chemical detectors currently in development are based on sensors that change color or pattern in the presence of the desired analytes. These changes are easily recorded and analyzed by a CMOS imager and an on-board DSP processor

  18. Report of the sensor cooler technology panel

    NASA Technical Reports Server (NTRS)

    Ross, Ronald; Castles, S.; Gautier, N.; Kittel, P.; Ludwigsen, J.

    1991-01-01

    The Sensor Cooler Technology Panel identified three major areas in which technology development must be supported in order to meet the system performance requirements for the Astrotech 21 mission set science objectives. They are: long life vibration free refrigerators; mechanical refrigeration for 2 K to 5 K; and flight testing of emerging prototype refrigerators. A development strategy and schedule were recommended for each of the three areas.

  19. All-fiber photoacoustic gas sensor with graphene nano-mechanical resonator as the acoustic detector

    NASA Astrophysics Data System (ADS)

    Yanzhen, Tan; Fan, Yang; Jun, Ma; Hoi Lut, Ho; Wei, Jin

    2015-09-01

    We demonstrate an all-optical-fiber photoacoustic (PA) spectrometric gas sensor with a graphene nano-mechanical resonator as the acoustic detector. The acoustic detection is performed by a miniature ferrule-top nano-mechanical resonator with a ˜100-nm-thick, 2.5-mm-diameter multilayer graphene diaphragm. Experimental investigation showed that the performance of the PA gas sensor can be significantly enhanced by operating at the resonance of the grapheme diaphragm where a lower detection limit of 153 parts-per-billion (ppb) acetylene is achieved. The all-fiber PA sensor which is immune to electromagnetic interference and safe in explosive environments is ideally suited for real-world remote, space-limited applications and for multipoint detection in a multiplexed fiber optic sensor network.

  20. Acoustic Detection Of Loose Particles In Pressure Sensors

    NASA Technical Reports Server (NTRS)

    Kwok, Lloyd C.

    1995-01-01

    Particle-impact-noise-detector (PIND) apparatus used in conjunction with computer program analyzing output of apparatus to detect extraneous particles trapped in pressure sensors. PIND tester essentially shaker equipped with microphone measuring noise in pressure sensor or other object being shaken. Shaker applies controlled vibration. Output of microphone recorded and expressed in terms of voltage, yielding history of noise subsequently processed by computer program. Data taken at sampling rate sufficiently high to enable identification of all impacts of particles on sensor diaphragm and on inner surfaces of sensor cavities.

  1. Selective Surface Acoustic Wave-Based Organophosphorus Sensor Employing a Host-Guest Self-Assembly Monolayer of β-Cyclodextrin Derivative.

    PubMed

    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 b-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

  2. 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

  3. 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. PMID:25643594

  4. 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.

  5. Integration of GMR Sensors with Different Technologies

    PubMed Central

    Cubells-Beltrán, María-Dolores; Reig, Càndid; Madrenas, Jordi; De Marcellis, Andrea; Santos, Joana; Cardoso, Susana; Freitas, Paulo P.

    2016-01-01

    Less than thirty years after the giant magnetoresistance (GMR) effect was described, GMR sensors are the preferred choice in many applications demanding the measurement of low magnetic fields in small volumes. This rapid deployment from theoretical basis to market and state-of-the-art applications can be explained by the combination of excellent inherent properties with the feasibility of fabrication, allowing the real integration with many other standard technologies. In this paper, we present a review focusing on how this capability of integration has allowed the improvement of the inherent capabilities and, therefore, the range of application of GMR sensors. After briefly describing the phenomenological basis, we deal on the benefits of low temperature deposition techniques regarding the integration of GMR sensors with flexible (plastic) substrates and pre-processed CMOS chips. In this way, the limit of detection can be improved by means of bettering the sensitivity or reducing the noise. We also report on novel fields of application of GMR sensors by the recapitulation of a number of cases of success of their integration with different heterogeneous complementary elements. We finally describe three fully functional systems, two of them in the bio-technology world, as the proof of how the integrability has been instrumental in the meteoric development of GMR sensors and their applications. PMID:27338415

  6. Integration of GMR Sensors with Different Technologies.

    PubMed

    Cubells-Beltrán, María-Dolores; Reig, Càndid; Madrenas, Jordi; De Marcellis, Andrea; Santos, Joana; Cardoso, Susana; Freitas, Paulo P

    2016-01-01

    Less than thirty years after the giant magnetoresistance (GMR) effect was described, GMR sensors are the preferred choice in many applications demanding the measurement of low magnetic fields in small volumes. This rapid deployment from theoretical basis to market and state-of-the-art applications can be explained by the combination of excellent inherent properties with the feasibility of fabrication, allowing the real integration with many other standard technologies. In this paper, we present a review focusing on how this capability of integration has allowed the improvement of the inherent capabilities and, therefore, the range of application of GMR sensors. After briefly describing the phenomenological basis, we deal on the benefits of low temperature deposition techniques regarding the integration of GMR sensors with flexible (plastic) substrates and pre-processed CMOS chips. In this way, the limit of detection can be improved by means of bettering the sensitivity or reducing the noise. We also report on novel fields of application of GMR sensors by the recapitulation of a number of cases of success of their integration with different heterogeneous complementary elements. We finally describe three fully functional systems, two of them in the bio-technology world, as the proof of how the integrability has been instrumental in the meteoric development of GMR sensors and their applications. PMID:27338415

  7. Characterization, monitoring, and sensor technology crosscutting program: Technology summary

    SciTech Connect

    1995-06-01

    The purpose of the Characterization, Monitoring, and Sensor Technology Crosscutting Program (CMST-CP) is to deliver appropriate characterization, monitoring, and sensor technology (CMST) to the Office of Waste Management (EM-30), the Office of Environmental Restoration (EM-40), and the Office of Facility Transition and Management (EM-60). The technology development must also be cost effective and appropriate to EM-30/40/60 needs. Furthermore, the required technologies must be delivered and implemented when needed. Accordingly, and to ensure that available DOE and other national resources are focused an the most pressing needs, management of the technology development is concentrated on the following Focus Areas: Contaminant Plume Containment and Remediation (PFA); Landfill Stabilization (LSFA); High-Level Waste Tank Remediation (TFA); Mixed Waste Characterization, Treatment, and Disposal (MWFA); and Facility Deactivation, Decommissioning, and Material Disposition (FDDMDFA). Brief descriptions of CMST-CP projects funded in FY95 are presented.

  8. Chemical sensors technology development planning workshop

    SciTech Connect

    Bastiaans, G.J.; Haas, W.J. Jr.; Junk, G.A.

    1993-03-01

    The workshop participants were asked to: (1) Assess the current capabilities of chemical sensor technologies for addressing US Department of Energy (DOE) Environmental Restoration and Waste Management (EM) needs; (2) Estimate potential near term (one to two years) and intermediate term (three to five years) capabilities for addressing those needs; and (3) Generate a ranked list of specific recommendations on what research and development (R&D) should be funded to provide the necessary capabilities. The needs were described in terms of two pervasive EM problems, the in situ determination of chlorinated volatile organic compounds (VOCs), and selected metals in various matrices at DOE sites. The R&D recommendations were to be ranked according to the estimated likelihood that the product technology will be ready for application within the time frame it is needed and the estimated return on investment. The principal conclusions and recommendations of the workshop are as follows: Chemical sensors capable of in situ determinations can significantly reduce analytical costs; Chemical sensors have been developed for certain VOCs in gases and water but none are currently capable of in situ determination of VOCs in soils; The DOE need for in situ determination of metals in soils cannot be addressed with existing chemical sensors and the prospects for their availability in three to five years are uncertain; Adaptation, if necessary, and field application of laboratory analytical instruments and those few chemical sensors that are already in field testing is the best approach for the near term; The chemical sensor technology development plan should include balanced support for near- and intermediate-term efforts.

  9. Bio-Inspired Miniature Direction Finding Acoustic Sensor

    PubMed Central

    Wilmott, Daniel; Alves, Fabio; Karunasiri, Gamani

    2016-01-01

    A narrowband MEMS direction finding sensor has been developed based on the mechanically coupled ears of the Ormia Ochracea fly. The sensor consists of two wings coupled at the middle and attached to a substrate using two legs. The sensor operates at its bending resonance frequency and has cosine directional characteristics similar to that of a pressure gradient microphone. Thus, the directional response of the sensor is symmetric about the normal axis making the determination of the direction ambiguous. To overcome this shortcoming two sensors were assembled with a canted angle similar to that employed in radar bearing locators. The outputs of two sensors were processed together allowing direction finding with no requirement of knowing the incident sound pressure level. At the bending resonant frequency of the sensors (1.69 kHz) an output voltage of about 25 V/Pa was measured. The angle uncertainty of the bearing of sound ranged from less than 0.3° close to the normal axis (0°) to 3.4° at the limits of coverage (±60°) based on the 30° canted angle used. These findings indicate the great potential to use dual MEMS direction finding sensor assemblies to locate sound sources with high accuracy. PMID:27440657

  10. Bio-Inspired Miniature Direction Finding Acoustic Sensor

    NASA Astrophysics Data System (ADS)

    Wilmott, Daniel; Alves, Fabio; Karunasiri, Gamani

    2016-07-01

    A narrowband MEMS direction finding sensor has been developed based on the mechanically coupled ears of the Ormia Ochracea fly. The sensor consists of two wings coupled at the middle and attached to a substrate using two legs. The sensor operates at its bending resonance frequency and has cosine directional characteristics similar to that of a pressure gradient microphone. Thus, the directional response of the sensor is symmetric about the normal axis making the determination of the direction ambiguous. To overcome this shortcoming two sensors were assembled with a canted angle similar to that employed in radar bearing locators. The outputs of two sensors were processed together allowing direction finding with no requirement of knowing the incident sound pressure level. At the bending resonant frequency of the sensors (1.69 kHz) an output voltage of about 25 V/Pa was measured. The angle uncertainty of the bearing of sound ranged from less than 0.3° close to the normal axis (0°) to 3.4° at the limits of coverage (±60°) based on the 30° canted angle used. These findings indicate the great potential to use dual MEMS direction finding sensor assemblies to locate sound sources with high accuracy.

  11. Bio-Inspired Miniature Direction Finding Acoustic Sensor.

    PubMed

    Wilmott, Daniel; Alves, Fabio; Karunasiri, Gamani

    2016-01-01

    A narrowband MEMS direction finding sensor has been developed based on the mechanically coupled ears of the Ormia Ochracea fly. The sensor consists of two wings coupled at the middle and attached to a substrate using two legs. The sensor operates at its bending resonance frequency and has cosine directional characteristics similar to that of a pressure gradient microphone. Thus, the directional response of the sensor is symmetric about the normal axis making the determination of the direction ambiguous. To overcome this shortcoming two sensors were assembled with a canted angle similar to that employed in radar bearing locators. The outputs of two sensors were processed together allowing direction finding with no requirement of knowing the incident sound pressure level. At the bending resonant frequency of the sensors (1.69 kHz) an output voltage of about 25 V/Pa was measured. The angle uncertainty of the bearing of sound ranged from less than 0.3° close to the normal axis (0°) to 3.4° at the limits of coverage (±60°) based on the 30° canted angle used. These findings indicate the great potential to use dual MEMS direction finding sensor assemblies to locate sound sources with high accuracy. PMID:27440657

  12. Laboratory comparisons of acoustic and optical sensors for microbubble measurement

    NASA Technical Reports Server (NTRS)

    Su, Ming Yang; Todoroff, Douglas; Cartmill, John

    1994-01-01

    This paper presents the results of a recent comparison between three microbubble size spectrum measurement systems. These systems are the light-scattering bubble counter, the photographic bubble-imaging system, and the acoustic resonator array. Good agreement was formed among these three systems over the bubble size range appropriate for each system.

  13. Advanced sensors, technology lower costs, boost productivity

    SciTech Connect

    Altpeter, L.L.; Kothari, K.

    1997-04-01

    Lower costs and higher productivity for the maintenance and repair of gas distribution systems has become an ever-increasing challenge to local distribution companies throughout the United States. A significant portion of costs for operations such as pipe location, leak pinpointing and leak surveying, arise from the inadequacies of their sensing technologies, some of which have not changed significantly in nearly 30 years. After reviewing the basic costs of pipe location, leak pinpointing, and leak surveying operations, the paper describes several advanced sensors for gas leak detection, and several sensors for pipe location and leak pinpointing.

  14. Advanced technologies for perimeter intrusion detection sensors

    SciTech Connect

    Williams, J.D.

    1995-03-01

    The development of integrated circuit fabrication techniques and the resulting devices have contributed more to the advancement of exterior intrusion detectors and alarm assessment devices than any other technology. The availability of this technology has led to the improvements in and further development of smaller more powerful computers, microprocessors, solid state memories, solid state cameras, thermal imagers, low-power lasers, and shorter pulse width and higher frequency electronic circuitry. This paper presents information on planning a perimeter intrusion detection system, identifies the site characteristics that affect its performance, and describes improvements to perimeter intrusion detection sensors and assessment devices that have been achieved by using integrated circuit technology.

  15. Method for simultaneously making a plurality of acoustic signal sensor elements

    NASA Technical Reports Server (NTRS)

    Bryant, Timothy D. (Inventor); Wynkoop, Mark W. (Inventor); Holloway, Nancy M. H. (Inventor); Zuckerwar, Allan J. (Inventor)

    2005-01-01

    A fetal heart monitoring system preferably comprising a backing plate having a generally concave front surface and a generally convex back surface, and at least one sensor element attached to the concave front surface for acquiring acoustic fetal heart signals produced by a fetus within a body. The sensor element has a shape that conforms to the generally concave back surface of the backing plate. In one embodiment, the at least one sensor element comprises an inner sensor, and a plurality of outer sensors surrounding the inner sensor. The fetal heart monitoring system can further comprise a web belt, and a web belt guide movably attached to the web belt. The web belt guide being is to the convex back surface of the backing plate.

  16. Technology towards a SAW based phononic crystal sensor

    NASA Astrophysics Data System (ADS)

    Schmidt, Marc-Peter; Oseev, Aleksandr; Lucklum, Ralf; Hirsch, Soeren

    2015-05-01

    Phononic crystals (PnC) with a specifically designed defect have been recently introduced as novel sensor platform. Those sensors feature a band gap covering the typical input span of the measurand as well as a narrow transmission peak within the band gap where the frequency of maximum transmission is governed by the measurand. This innovative approach has been applied for determination of compounds in liquids [1]. Improvement of sensitivity requires higher probing frequencies around 100 MHz and above. In this range surface acoustic wave devices (SAW) provide a promising basis for PnC based microsensors [2]. The respective feature size of the PnC SAW sensor has dimensions in the range of 100 μm and below. Whereas those dimensions are state of the art for common MEMS materials, etching of holes and cavities in piezoelectric materials having an aspect ratio diameter/depth is challenging. In this contribution we describe an improved technological process to manufacture considerably deep and uniform phononic crystal structures inside of SAW substrates.

  17. Job-Oriented Basic Skills (JOBS) Program for the Acoustic Sensor Operations Strand.

    ERIC Educational Resources Information Center

    U'Ren, Paula Kabance; Baker, Meryl S.

    An effort was undertaken to develop a job-oriented basic skills curriculum appropriate for the acoustic sensor operations area, which includes members of four ratings: ocean systems technician, aviation antisubmarine warfare operator, sonar technician (surface), and sonar technician (submarine). Analysis of the job duties of the four ratings…

  18. Detection of chemical or biological artillery attacks using a seismic/acoustic sensor: preliminary results

    NASA Astrophysics Data System (ADS)

    Baker, Vincent J.; Walter, Paul A.

    2004-04-01

    Chemical and biological weapons pose a serious threat to the United States armed forces. Early detection of a chemical or biological attack is critical to the safety of soldiers in the field. The Edgewood Chemical and Biological Center (ECBC) is conducting a study using currently fielded seismic and acoustic sensors to detect chemical and biological attacks. This paper presents some preliminary results.

  19. A thickness mode acoustic wave sensor for measuring interface stiffness between two elastic materials.

    PubMed

    Chen, Jiankang; Wang, Wencai; Wang, Ji; Yang, Zengtao; Yang, Jiashi

    2008-08-01

    We studied thickness vibration of 2 elastic layers with an elastic interface mounted on a plate piezoelectric resonator. The effect of the interface elasticity on resonant frequencies was examined. The result obtained suggests an acoustic wave sensor for measuring the elastic property of an interface between 2 materials. PMID:18986911

  20. Hydrogen-Bond Basic Siloxane Phosphonate Polymers for Surface Acoustic Wave (Saw) Sensors

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A surface acoustic wave (SAW) sensor coated with a novel hydrogen-bond basic siloxane phosphonate SAW polymer gave excellent initial response and long-term performance when tested against phenol vapor and compared with polyethyleneimine (PEI), a conventional hydrogent-bond basic SAW polymer....

  1. Simulation of vehicle acoustics in support of netted sensor research and development

    NASA Astrophysics Data System (ADS)

    Christou, Carol T.; Jacyna, Garry M.

    2005-05-01

    The MITRE Corporation has initiated a three-year internally-funded research program in netted sensors, the first-year effort focusing on vehicle detection for border monitoring. An important component is developing an understanding of the complex acoustic structure of vehicle noise to aid in netted sensor-based detection and classification. This presentation will discuss the design of a high-fidelity vehicle acoustic simulator to model the generation and transmission of acoustic energy from a moving vehicle to a collection of sensor nodes. Realistic spatially-dependent automobile sounds are generated from models of the engine cylinder firing rates, muffler and manifold resonances, and speed-dependent tire whine noise. Tire noise is the dominant noise source for vehicle speeds in excess of 30 miles per hour (MPH). As a result, we have developed detailed models that successfully predict the tire noise spectrum as a function of speed, road surface wave-number spectrum, tire geometry, and tire tread pattern. We have also included realistic descriptions of the spatial directivity patterns for the engine harmonics, muffler, and tire whine noise components. The acoustic waveforms are propagated to each sensor node using a simple phase-dispersive multi-path model. A brief description of the models and their corresponding outputs is provided.

  2. Development of a standing wave apparatus for calibrating acoustic vector sensors and hydrophones.

    PubMed

    Lenhart, Richard D; Sagers, Jason D; Wilson, Preston S

    2016-01-01

    An apparatus was developed to calibrate acoustic hydrophones and vector sensors between 25 and 2000 Hz. A standing wave field is established inside a vertically oriented, water-filled, elastic-walled waveguide by a piston velocity source at the bottom and a pressure-release boundary condition at the air/water interface. A computer-controlled linear positioning system allows a device under test to be precisely located in the water column while the acoustic response is measured. Some of the challenges of calibrating hydrophones and vector sensors in such an apparatus are discussed, including designing the waveguide to mitigate dispersion, understanding the impact of waveguide structural resonances on the acoustic field, and developing algorithms to post-process calibration measurement data performed in a standing wave field. Data from waveguide characterization experiments and calibration measurements are presented and calibration uncertainty is reported. PMID:26827015

  3. Acoustic charge transport technology investigation for advanced development transponder

    NASA Technical Reports Server (NTRS)

    Kayalar, S.

    1993-01-01

    Acoustic charge transport (ACT) technology has provided a basis for a new family of analog signal processors, including a programmable transversal filter (PTF). Through monolithic integration of ACT delay lines with GaAs metal semiconductor field effect transistor (MESFET) digital memory and controllers, these devices significantly extend the performance of PTF's. This article introduces the basic operation of these devices and summarizes their present and future specifications. The production and testing of these devices indicate that this new technology is a promising one for future space applications.

  4. Use of acoustic sensors to probe the mechanical properties of liposomes.

    PubMed

    Melzak, Kathryn; Tsortos, Achilleas; Gizeli, Electra

    2009-01-01

    Acoustic sensors probe the response of a thin layer to the mechanical displacement associated with an acoustic wave. Acoustic measurements provide two simultaneous time-resolved signals; one signal is related to the velocity or frequency of the acoustic wave and is mainly a function of adsorbed mass, while the second signal, related to the oscillation amplitude, is associated with energy dissipation and is a function of the viscoelastic properties of the adsorbed layer. The methods described in this chapter explore the relationship between the acoustic measurements of adsorbed liposomes and the mechanical properties of the lipid bilayer. This is carried out using a well-characterized model system consisting of liposomes prepared from an unsaturated phospholipid and a range of mole fractions of cholesterol. Real-time acoustic measurements are shown to be sensitive to changes in the liposome cholesterol content, regardless of the mode of attachment of the liposome to the device surface. This sensitivity is not due to changes in the density of the bilayer, or to changes in the extent of liposome-surface interactions, thus leaving the mechanical properties of the bilayer as the feature that is probably being measured. Some mechanisms by which the acoustic response could be generated are suggested in this chapter. PMID:19913160

  5. Experimental Study of Highly Sensitive Sensor Using a Surface Acoustic Wave Resonator for Wireless Strain Detection

    NASA Astrophysics Data System (ADS)

    Bao; Zhongqing; Hara, Motoaki; Mitsui, Misato; Sano, Koji; Nagasawa, Sumito; Kuwano, Hiroki

    2012-07-01

    We developed a highly sensitive strain sensor employing a surface acoustic wave (SAW) resonator for a wireless sensing system. The aim of this study is to monitor the distribution of the strain in the earth crust or giant infrastructures, such as bridges, skyscrapers and power plants, for disaster prevention. A SAW strain sensor was fabricated using LiNbO3 and a quartz substrate, and applied in a tensile test by attaching the steel specimen based on Japanese Industrial Standards (JIS Z2441-1). The results confirmed that the developed sensor could detect a strain of 10-6 order with linearity.

  6. A methodology for analyzing an acoustic scene in sensor arrays

    NASA Astrophysics Data System (ADS)

    Man, Hong; Hohil, Myron E.; Desai, Sachi

    2007-10-01

    Presented here is a novel clustering method for Hidden Markov Models (HMMs) and its application in acoustic scene analysis. In this method, HMMs are clustered based on a similarity measure for stochastic models defined as the generalized probability product kernel (GPPK), which can be efficiently evaluated according to a fast algorithm introduced by Chen and Man (2005) [1]. Acoustic signals from various sources are partitioned into small frames. Frequency features are extracted from each of the frames to form observation vectors. These frames are further grouped into segments, and an HMM is trained from each of such segments. An unknown segment is categorized with a known event if its HMM has the closest similarity with the HMM from the corresponding labeled segment. Experiments are conducted on an underwater acoustic dataset from Steven Maritime Security Laboratory, Data set contains a swimmer signature, a noise signature from the Hudson River, and a test sequence with a swimmer in the Hudson River. Experimental results show that the proposed method can successfully associate the test sequence with the swimmer signature at very high confidence, despite their different time behaviors.

  7. Wireless surface acoustic wave sensors for displacement and crack monitoring in concrete structures

    NASA Astrophysics Data System (ADS)

    Perry, M.; McKeeman, I.; Saafi, M.; Niewczas, P.

    2016-03-01

    In this work, we demonstrate that wireless surface acoustic wave devices can be used to monitor millimetre displacements in crack opening during the cyclic and static loading of reinforced concrete structures. Sensors were packaged to extend their gauge length and to protect them against brittle fracture, before being surface-mounted onto the tensioned surface of a concrete beam. The accuracy of measurements was verified using computational methods and optical-fibre strain sensors. After packaging, the displacement and temperature resolutions of the surface acoustic wave sensors were 10 μ {{m}} and 2 °C respectively. With some further work, these devices could be retrofitted to existing concrete structures to facilitate wireless structural health monitoring.

  8. Sensor Technologies for Particulate Detection and Characterization

    NASA Technical Reports Server (NTRS)

    Greenberg, Paul S.

    2008-01-01

    Planned Lunar missions have resulted in renewed attention to problems attributable to fine particulates. While the difficulties experienced during the sequence of Apollo missions did not prove critical in all cases, the comparatively long duration of impending missions may present a different situation. This situation creates the need for a spectrum of particulate sensing technologies. From a fundamental perspective, an improved understanding of the properties of the dust fraction is required. Described here is laboratory-based reference instrumentation for the measurement of fundamental particle size distribution (PSD) functions from 2.5 nanometers to 20 micrometers. Concomitant efforts for separating samples into fractional size bins are also presented. A requirement also exists for developing mission compatible sensors. Examples include provisions for air quality monitoring in spacecraft and remote habitation modules. Required sensor attributes such as low mass, volume, and power consumption, autonomy of operation, and extended reliability cannot be accommodated by existing technologies.

  9. Transport composite fuselage technology: Impact dynamics and acoustic transmission

    NASA Technical Reports Server (NTRS)

    Jackson, A. C.; Balena, F. J.; Labarge, W. L.; Pei, G.; Pitman, W. A.; Wittlin, G.

    1986-01-01

    A program was performed to develop and demonstrate the impact dynamics and acoustic transmission technology for a composite fuselage which meets the design requirements of a 1990 large transport aircraft without substantial weight and cost penalties. The program developed the analytical methodology for the prediction of acoustic transmission behavior of advanced composite stiffened shell structures. The methodology predicted that the interior noise level in a composite fuselage due to turbulent boundary layer will be less than in a comparable aluminum fuselage. The verification of these analyses will be performed by NASA Langley Research Center using a composite fuselage shell fabricated by filament winding. The program also developed analytical methodology for the prediction of the impact dynamics behavior of lower fuselage structure constructed with composite materials. Development tests were performed to demonstrate that the composite structure designed to the same operating load requirement can have at least the same energy absorption capability as aluminum structure.

  10. Integration of acoustical sensors into the KM3NeT optical modules

    SciTech Connect

    Enzenhöfer, A.; Collaboration: KM3NeT Collaboration

    2014-11-18

    The next generation multi-cubic-kilometre water Cherenkov neutrino telescope will be build in the Mediterranean Sea. This telescope, called KM3NeT, is currently entering a first construction phase. The KM3NeT research infrastructure will comprise 690 so-called Detection Units in its final design which will be anchored to the sea bed and held upright by submerged floats. The positions of these Detection Units, several hundred metres in length, and their attached Optical Modules for the detection of Cherenkov light have to be monitored continously to provide the telescope with its desired pointing precision. A standard way to do this is the utilisation of an acoustic positioning system using emitters at fixed positions and receivers distributed along the Detection Units. The KM3NeT neutrino telescope comprises a custom-made acoustic positioning system with newly designed emitters attached to the anchors of the Detection Units and custom-designed receivers attached to the Detection Units. This article describes an approach for a receiver and its performance. The proposed Opto-Acoustical Modules combine the optical sensors for the telescope with the acoustical sensors necessary for the positioning of the module itself. This combination leads to a compact design suited for an easy deployment of the numerous Detection Units. Furthermore, the instrumented volume can be used for scientific analyses such as marine science and acoustic particle detection.

  11. 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.

  12. A self-mixing based ring-type fiber-optic acoustic sensor

    NASA Astrophysics Data System (ADS)

    Wang, Lutang; Wu, Chunxu; Fang, Nian

    2014-07-01

    A novel, simple fiber-optic acoustic sensor consisting of a self-mixing effect based laser source and a ring-type interferometer is presented. With weak external optical feedbacks, the acoustic wave signals can be detected by measuring the changes of oscillating frequency of the laser diode, induced by the disturbances of sensing fiber, with the ring-type interferometer. The operation principles of the sensor system are explored in-depth and the experimental researches are carried out. The acoustic wave signals produced by various actions, such as by pencil broken, mental pin free falling and PZT are detected for evaluating the sensing performances of the experimental system. The investigation items include the sensitivity as well as frequency responses of the sensor system. An experiment for the detection of corona discharges is carried out, which occur in a high-voltage environment between two parallel copper electrodes, under different humidity levels. The satisfied experimental results are obtained. These experimental results well prove that our proposed sensing system has very high sensitivity and excellent high frequency responses characteristics in the detections of weak, high-frequency acoustic wave signals.

  13. Acoustic vibration sensor based on nonadiabatic tapered fibers.

    PubMed

    Xu, Ben; Li, Yi; Sun, Miao; Zhang, Zhen-Wei; Dong, Xin-Yong; Zhang, Zai-Xuan; Jin, Shang-Zhong

    2012-11-15

    A simple and low-cost vibration sensor based on single-mode nonadiabatic fiber tapers is proposed and demonstrated. The environmental vibrations can be detected by demodulating the transmission loss of the nonadiabatic fiber taper. Theoretical simulations show that the transmission loss is related to the microbending of the fiber taper induced by vibrations. Unlike interferometric sensors, this vibration sensor does not need any feedback loop to control the quadrature point to obtain a stable performance. In addition, it has no requirement for the coherence of the light source and is insensitive to temperature changes. Experimental results show that this sensing system has a wide frequency response range from a few hertz to tens of kilohertz with the maximal signal to noise ratio up to 73 dB. PMID:23164907

  14. Scattering reduction for an acoustic sensor using a multilayered shell comprising a pair of homogeneous isotropic single-negative media

    NASA Astrophysics Data System (ADS)

    Xu, Tao; Zhu, Xue-Feng; Liang, Bin; Li, Yong; Zou, Xin-Ye; Cheng, Jian-Chun

    2012-07-01

    We have designed a cylindrical multilayered structure to reduce scattering for an acoustic sensor while allowing it to receive external information. The proposed structure consists of two alternately arranged complementary media with homogeneous isotropic single-negative parameters. Numerical results show that the acoustic scattering from the sensor is suppressed considerably when the number of bilayers is large enough and the thickness of each bilayer is much smaller than the incident wavelength. This may be particularly significant for practical applications where acoustic measurements would otherwise be disturbed by the insertion of sensors.

  15. Sensor technology in the era of nanotechnology

    NASA Astrophysics Data System (ADS)

    Ren, Shu; Zhou, Yikai; Wu, Meng

    2001-09-01

    In this paper, nano technology, nano sensor, nano devices, bionics of nano technology are discussed. The significance of the topic includes its contribution to biology and medicine as well as to engineering and technology. Cell may be the best object to be researched. Cell membrane may be the key of such a study. By means of simulating the structure and function of a cell's membrane, a molecular network model of nanofactory are suggested. Methodologies for realizing such models are presented. Among them, nano fabrication biotechnology, chemical method and nano integration are illustrated. Nano fabrication in a broad sense will be preferable to others. At last, a diagram showing the perspectives of the new technologies including measuring and control of psychological state, establishing platform for monitoring a single cell, constructing nano robot and nanofactory etc. was depicted.

  16. Condition monitoring through advanced sensor and computational technology : final report (January 2002 to May 2005).

    SciTech Connect

    Kim, Jung-Taek; Luk, Vincent K.

    2005-05-01

    The overall goal of this joint research project was to develop and demonstrate advanced sensors and computational technology for continuous monitoring of the condition of components, structures, and systems in advanced and next-generation nuclear power plants (NPPs). This project included investigating and adapting several advanced sensor technologies from Korean and US national laboratory research communities, some of which were developed and applied in non-nuclear industries. The project team investigated and developed sophisticated signal processing, noise reduction, and pattern recognition techniques and algorithms. The researchers installed sensors and conducted condition monitoring tests on two test loops, a check valve (an active component) and a piping elbow (a passive component), to demonstrate the feasibility of using advanced sensors and computational technology to achieve the project goal. Acoustic emission (AE) devices, optical fiber sensors, accelerometers, and ultrasonic transducers (UTs) were used to detect mechanical vibratory response of check valve and piping elbow in normal and degraded configurations. Chemical sensors were also installed to monitor the water chemistry in the piping elbow test loop. Analysis results of processed sensor data indicate that it is feasible to differentiate between the normal and degraded (with selected degradation mechanisms) configurations of these two components from the acquired sensor signals, but it is questionable that these methods can reliably identify the level and type of degradation. Additional research and development efforts are needed to refine the differentiation techniques and to reduce the level of uncertainties.

  17. A reverse localization scheme for underwater acoustic sensor networks.

    PubMed

    Moradi, Marjan; Rezazadeh, Javad; Ismail, Abdul Samad

    2012-01-01

    Underwater Wireless Sensor Networks (UWSNs) provide new opportunities to observe and predict the behavior of aquatic environments. In some applications like target tracking or disaster prevention, sensed data is meaningless without location information. In this paper, we propose a novel 3D centralized, localization scheme for mobile underwater wireless sensor network, named Reverse Localization Scheme or RLS in short. RLS is an event-driven localization method triggered by detector sensors for launching localization process. RLS is suitable for surveillance applications that require very fast reactions to events and could report the location of the occurrence. In this method, mobile sensor nodes report the event toward the surface anchors as soon as they detect it. They do not require waiting to receive location information from anchors. Simulation results confirm that the proposed scheme improves the energy efficiency and reduces significantly localization response time with a proper level of accuracy in terms of mobility model of water currents. Major contributions of this method lie on reducing the numbers of message exchange for localization, saving the energy and decreasing the average localization response time. PMID:22666034

  18. A Reverse Localization Scheme for Underwater Acoustic Sensor Networks

    PubMed Central

    Moradi, Marjan; Rezazadeh, Javad; Ismail, Abdul Samad

    2012-01-01

    Underwater Wireless Sensor Networks (UWSNs) provide new opportunities to observe and predict the behavior of aquatic environments. In some applications like target tracking or disaster prevention, sensed data is meaningless without location information. In this paper, we propose a novel 3D centralized, localization scheme for mobile underwater wireless sensor network, named Reverse Localization Scheme or RLS in short. RLS is an event-driven localization method triggered by detector sensors for launching localization process. RLS is suitable for surveillance applications that require very fast reactions to events and could report the location of the occurrence. In this method, mobile sensor nodes report the event toward the surface anchors as soon as they detect it. They do not require waiting to receive location information from anchors. Simulation results confirm that the proposed scheme improves the energy efficiency and reduces significantly localization response time with a proper level of accuracy in terms of mobility model of water currents. Major contributions of this method lie on reducing the numbers of message exchange for localization, saving the energy and decreasing the average localization response time. PMID:22666034

  19. Color filtering localization for three-dimensional underwater acoustic sensor networks.

    PubMed

    Liu, Zhihua; Gao, Han; Wang, Wuling; Chang, Shuai; Chen, Jiaxing

    2015-01-01

    Accurate localization of mobile nodes has been an important and fundamental problem in underwater acoustic sensor networks (UASNs). The detection information returned from a mobile node is meaningful only if its location is known. In this paper, we propose two localization algorithms based on color filtering technology called PCFL and ACFL. PCFL and ACFL aim at collaboratively accomplishing accurate localization of underwater mobile nodes with minimum energy expenditure. They both adopt the overlapping signal region of task anchors which can communicate with the mobile node directly as the current sampling area. PCFL employs the projected distances between each of the task projections and the mobile node, while ACFL adopts the direct distance between each of the task anchors and the mobile node. The proportion factor of distance is also proposed to weight the RGB values. By comparing the nearness degrees of the RGB sequences between the samples and the mobile node, samples can be filtered out. The normalized nearness degrees are considered as the weighted standards to calculate the coordinates of the mobile nodes. The simulation results show that the proposed methods have excellent localization performance and can localize the mobile node in a timely way. The average localization error of PCFL is decreased by about 30.4% compared to the AFLA method. PMID:25774706

  20. Color Filtering Localization for Three-Dimensional Underwater Acoustic Sensor Networks

    PubMed Central

    Liu, Zhihua; Gao, Han; Wang, Wuling; Chang, Shuai; Chen, Jiaxing

    2015-01-01

    Accurate localization of mobile nodes has been an important and fundamental problem in underwater acoustic sensor networks (UASNs). The detection information returned from a mobile node is meaningful only if its location is known. In this paper, we propose two localization algorithms based on color filtering technology called PCFL and ACFL. PCFL and ACFL aim at collaboratively accomplishing accurate localization of underwater mobile nodes with minimum energy expenditure. They both adopt the overlapping signal region of task anchors which can communicate with the mobile node directly as the current sampling area. PCFL employs the projected distances between each of the task projections and the mobile node, while ACFL adopts the direct distance between each of the task anchors and the mobile node. The proportion factor of distance is also proposed to weight the RGB values. By comparing the nearness degrees of the RGB sequences between the samples and the mobile node, samples can be filtered out. The normalized nearness degrees are considered as the weighted standards to calculate the coordinates of the mobile nodes. The simulation results show that the proposed methods have excellent localization performance and can localize the mobile node in a timely way. The average localization error of PCFL is decreased by about 30.4% compared to the AFLA method. PMID:25774706

  1. Tutorial on the Psychophysics and Technology of Virtual Acoustic Displays

    NASA Technical Reports Server (NTRS)

    Wenzel, Elizabeth M.; Null, Cynthia (Technical Monitor)

    1998-01-01

    Virtual acoustics, also known as 3-D sound and auralization, is the simulation of the complex acoustic field experienced by a listener within an environment. Going beyond the simple intensity panning of normal stereo techniques, the goal is to process sounds so that they appear to come from particular locations in three-dimensional space. Although loudspeaker systems are being developed, most of the recent work focuses on using headphones for playback and is the outgrowth of earlier analog techniques. For example, in binaural recording, the sound of an orchestra playing classical music is recorded through small mics in the two "ear canals" of an anthropomorphic artificial or "dummy" head placed in the audience of a concert hall. When the recorded piece is played back over headphones, the listener passively experiences the illusion of hearing the violins on the left and the cellos on the right, along with all the associated echoes, resonances, and ambience of the original environment. Current techniques use digital signal processing to synthesize the acoustical properties that people use to localize a sound source in space. Thus, they provide the flexibility of a kind of digital dummy head, allowing a more active experience in which a listener can both design and move around or interact with a simulated acoustic environment in real time. Such simulations are being developed for a variety of application areas including architectural acoustics, advanced human-computer interfaces, telepresence and virtual reality, navigation aids for the visually-impaired, and as a test bed for psychoacoustical investigations of complex spatial cues. The tutorial will review the basic psychoacoustical cues that determine human sound localization and the techniques used to measure these cues as Head-Related Transfer Functions (HRTFs) for the purpose of synthesizing virtual acoustic environments. The only conclusive test of the adequacy of such simulations is an operational one in which

  2. Unattended acoustic sensor simulation of TG25 trials using CHORALE workshop

    NASA Astrophysics Data System (ADS)

    Gozard, Patrick; Le Goff, Alain; Naz, Pierre; Cathala, Thierry; Latger, Jean; Dupuy, Yann

    2004-08-01

    The simulation workshop CHORALE of the French DGA is used by government services and industrial companies for weapon system validation and qualification trials in the infrared domain, and detection of moving vehicles in the acoustic domain. Recently, acoustic simulation tests were performed on the 3D geometrical database of the DGA/DCE/ETBS proving ground. Results have been compared to the acoustic measurements of the NATO-TG25 trials. This article describes the trials, the modeling of the 3D geometrical database and the comparison between acoustic simulation results and measurements. The 3D scene is described by a set of polygons. Each polygon is characterized by its acoustic resistivity or its complex impedance. Sound sources are associated with moving vehicles and are characterized by their spectra and directivities. A microphone sensor is defined by its position, its frequency band and its directivity. For each trial, atmospheric profiles (air temperature, pressure and humidity according to altitude), trajectories and sound spectrum of moving objects were measured. These data were used to prepare the scenario for the acoustic simulation.

  3. Experimental Results of Underwater Cooperative Source Localization Using a Single Acoustic Vector Sensor

    PubMed Central

    Felisberto, Paulo; Rodriguez, Orlando; Santos, Paulo; Ey, Emanuel; Jesus, Sérgio M.

    2013-01-01

    This paper aims at estimating the azimuth, range and depth of a cooperative broadband acoustic source with a single vector sensor in a multipath underwater environment, where the received signal is assumed to be a linear combination of echoes of the source emitted waveform. A vector sensor is a device that measures the scalar acoustic pressure field and the vectorial acoustic particle velocity field at a single location in space. The amplitudes of the echoes in the vector sensor components allow one to determine their azimuth and elevation. Assuming that the environmental conditions of the channel are known, source range and depth are obtained from the estimates of elevation and relative time delays of the different echoes using a ray-based backpropagation algorithm. The proposed method is tested using simulated data and is further applied to experimental data from the Makai'05 experiment, where 8–14 kHz chirp signals were acquired by a vector sensor array. It is shown that for short ranges, the position of the source is estimated in agreement with the geometry of the experiment. The method is low computational demanding, thus well-suited to be used in mobile and light platforms, where space and power requirements are limited. PMID:23857257

  4. Experimental results of underwater cooperative source localization using a single acoustic vector sensor.

    PubMed

    Felisberto, Paulo; Rodriguez, Orlando; Santos, Paulo; Ey, Emanuel; Jesus, Sérgio M

    2013-01-01

    This paper aims at estimating the azimuth, range and depth of a cooperative broadband acoustic source with a single vector sensor in a multipath underwater environment, where the received signal is assumed to be a linear combination of echoes of the source emitted waveform. A vector sensor is a device that measures the scalar acoustic pressure field and the vectorial acoustic particle velocity field at a single location in space. The amplitudes of the echoes in the vector sensor components allow one to determine their azimuth and elevation. Assuming that the environmental conditions of the channel are known, source range and depth are obtained from the estimates of elevation and relative time delays of the different echoes using a ray-based backpropagation algorithm. The proposed method is tested using simulated data and is further applied to experimental data from the Makai'05 experiment, where 8-14 kHz chirp signals were acquired by a vector sensor array. It is shown that for short ranges, the position of the source is estimated in agreement with the geometry of the experiment. The method is low computational demanding, thus well-suited to be used in mobile and light platforms, where space and power requirements are limited. PMID:23857257

  5. Theoretical detection ranges for acoustic based manatee avoidance technology.

    PubMed

    Phillips, Richard; Niezrecki, Christopher; Beusse, Diedrich O

    2006-07-01

    The West Indian manatee (Trichechus manatus latirostris) has become endangered partly because of watercraft collisions in Florida's coastal waterways. To reduce the number of collisions, warning systems based upon detecting manatee vocalizations have been proposed. One aspect of the feasibility of an acoustically based warning system relies upon the distance at which a manatee vocalization is detectable. Assuming a mixed spreading model, this paper presents a theoretical analysis of the system detection capabilities operating within various background and watercraft noise conditions. This study combines measured source levels of manatee vocalizations with the modeled acoustic properties of manatee habitats to develop a method for determining the detection range and hydrophone spacing requirements for acoustic based manatee avoidance technologies. In quiet environments (background noise approximately 70 dB) it was estimated that manatee vocalizations are detectable at approximately 250 m, with a 6 dB detection threshold, In louder environments (background noise approximately 100dB) the detection range drops to 2.5 m. In a habitat with 90 dB of background noise, a passing boat with a maximum noise floor of 120 dB would be the limiting factor when it is within approximately 100 m of a hydrophone. The detection range was also found to be strongly dependent on the manatee vocalization source level. PMID:16875213

  6. Precursory Acoustic Signals Detection in Rockfall Events by Means of Optical Fiber Sensors

    NASA Astrophysics Data System (ADS)

    Schenato, L.; Marcato, G.; Gruca, G.; Iannuzzi, D.; Palmieri, L.; Galtarossa, A.; Pasuto, A.

    2012-12-01

    Rockfalls represent a major source of hazard in mountain areas: they occur at the apex of a process of stress accumulation in the unstable slope, during which part of the accumulated energy is released in small internal cracks. These cracks and the related acoustic emissions (AE) can, therefore, be used as precursory signals, through which the unstable rock could be monitored. In particular, according to previous scientific literature AE can be monitored in the range 20÷100 kHz. With respect to traditional AE sensors, such as accelerometers and piezoelectric transducers, fiber optic sensors (FOSs) may provide a reliable solution, potentially offering more robustness to electromagnetic interference, smaller form factor, multiplexing ability and increased distance range and higher sensitivity. To explore this possibility, in this work we have experimentally analyzed two interferometric fiber optical sensors for AE detection in rock masses. In particular, the first sensor is made of 100 m of G.657 optical fiber, tightly wound on an aluminum flanged hollow mandrel (inner diameter 30 mm, height 42 mm) that is isolated from the environment with acoustic absorbing material. A 4-cm-long M10 screw, which acts also as the main mean of acoustic coupling between the rock and the sensor, is used to fasten the sensor to the rock. This fiber coil sensor (FCS) is inserted in the sensing arm of a fiber Mach-Zehnder interferometer. The second sensor consists in a micro cantilever carved on the top of a cylindrical silica ferrule, with a marked mechanical resonance at about 12.5 kHz (Q-factor of about 400). A standard single mode fiber is housed in the same ferrule and the gap between the cantilever and the fiber end face acts as a vibration-sensitive Fabry-Perot cavity, interrogated with a low-coherence laser, tuned at the quadrature point of the cavity. The sensor is housed in a 2-cm-long M10 bored bolt. Performance have been compared with those from a standard piezo

  7. Physical and chemical sensor technologies developed at Lawrence Livermore National Laboratory

    SciTech Connect

    Balch, J.W.; Ciarlo, D.; Folta, J.; Glass, R.; Hagans, K.; Milanovich, F.; Sheem, S.

    1993-08-10

    The increasing emphasis on envirorunental issues, waste reduction, and improved efficiency for industrial processes has mandated the development of new chemical and physical sensors for field or in-plant use. The Lawrence Livermore National Laboratory (LLNL) has developed a number of technologies for sensing physical and chemical properties. Table 1 gives some examples of several sensors. that have been developed recently for environmental, industrial, commercial or government applications. Physical sensors of pressure, temperature, acceleration, acoustic vibration spectra, and ionizing radiation have been developed. Sensors developed at LLNL for chemical species include inorganic solvents, heavy metal ions`, and gaseous atoms and compounds. Primary sensing technologies we have employed have been based on optical fibers, semiconductor optical or radiation detectors, electrochemical activity, micromachined electromechanical (MEMs) structures, or chemical separation technologies. The complexities of these sensor systems range from single detectors to more advanced micro-instruments on-a-chip. For many of the sensors we have developed the necessary intelligent electronic support systems for both local and remote sensing applications. Each of these sensor technologies are briefly described in the remaining sections of this paper.

  8. Klamath Falls: High-Power Acoustic Well Stimulation Technology

    SciTech Connect

    Black, Brian

    2006-07-24

    Acoustic well stimulation (AWS) technology uses high-power sonic waves from specific frequency spectra in an attempt to stimulate production in a damaged or low-production wellbore. AWS technology is one of the most promising technologies in the oil and gas industry, but it has proven difficult for the industry to develop an effective downhole prototype. This collaboration between Klamath Falls Inc. and the Rocky Mountain Oilfield Testing Center (RMOTC) included a series of tests using high-power ultrasonic tools to stimulate oil and gas production. Phase I testing was designed and implemented to verify tool functionality, power requirements, and capacity of high-power AWS tools. The purpose of Phase II testing was to validate the production response of wells with marginal production rates to AWS stimulation and to capture and identify any changes in the downhole environment after tool deployment. This final report presents methodology and results.

  9. 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).

  10. Sensor technology for future atmospheric observation systems

    NASA Technical Reports Server (NTRS)

    Alvarado, U. R.; Keafer, L. S., Jr.

    1982-01-01

    The remote sensing instruments that will be needed for research in atmospheric environmental quality in the future are considered. The needs are determined on the basis of a model that incorporates scientific knowledge objectives, measurement needs, and potential space missions, spacecraft and instruments in order to discern the technology requirements. While emphasis is placed on global surveys that make full use of the synoptic observation capabilities of spaceborne sensors, the importance of airborne and ground-based sensors in this research is also recognized. Several of the instruments that are identified to fulfill the knowledge objectives are spectrometers and radiometers using such passive measurement techniques as interferometer correlation absorption radiometry, and heterodyne spectrometry. Lidar instruments are also seen as important future developments.

  11. CMOS digital pixel sensors: technology and applications

    NASA Astrophysics Data System (ADS)

    Skorka, Orit; Joseph, Dileepan

    2014-04-01

    CMOS active pixel sensor technology, which is widely used these days for digital imaging, is based on analog pixels. Transition to digital pixel sensors can boost signal-to-noise ratios and enhance image quality, but can increase pixel area to dimensions that are impractical for the high-volume market of consumer electronic devices. There are two main approaches to digital pixel design. The first uses digitization methods that largely rely on photodetector properties and so are unique to imaging. The second is based on adaptation of a classical analog-to-digital converter (ADC) for in-pixel data conversion. Imaging systems for medical, industrial, and security applications are emerging lower-volume markets that can benefit from these in-pixel ADCs. With these applications, larger pixels are typically acceptable, and imaging may be done in invisible spectral bands.

  12. A cantilever based optical fiber acoustic sensor fabricated by femtosecond laser micromachining

    NASA Astrophysics Data System (ADS)

    Liu, Jie; Yuan, Lei; Huang, Jie; Xiao, Hai

    2016-04-01

    In this paper, we present a pure silica micro-cantilever based optical fiber sensor for acoustic wave detection. The cantilever is directly fabricated by fs laser micromachining on an optical fiber tip functioning as an inline Fabry-Perot interferometer (FPI). The applied acoustic wave pressurizes the micro-cantilever beam and the corresponding dynamic signals can be probed by the FPI. The thickness, length, and width of the micro-cantilever beam can be flexibly designed and fabricated so that the sensitivity, frequency response, and the total measurement range can be varied to fit many practical applications. Experimental results will be presented and analyzed. Due to the assembly free fabrication of the fs-laser, multiple micro-cantilever beams could be potentially fabricated in/on a single optical fiber for quasi-distributed acoustic mapping with high spatial resolution.

  13. Source Localization with Acoustic Sensor Arrays Using Generative Model Based Fitting with Sparse Constraints

    PubMed Central

    Velasco, Jose; Pizarro, Daniel; Macias-Guarasa, Javier

    2012-01-01

    This paper presents a novel approach for indoor acoustic source localization using sensor arrays. The proposed solution starts by defining a generative model, designed to explain the acoustic power maps obtained by Steered Response Power (SRP) strategies. An optimization approach is then proposed to fit the model to real input SRP data and estimate the position of the acoustic source. Adequately fitting the model to real SRP data, where noise and other unmodelled effects distort the ideal signal, is the core contribution of the paper. Two basic strategies in the optimization are proposed. First, sparse constraints in the parameters of the model are included, enforcing the number of simultaneous active sources to be limited. Second, subspace analysis is used to filter out portions of the input signal that cannot be explained by the model. Experimental results on a realistic speech database show statistically significant localization error reductions of up to 30% when compared with the SRP-PHAT strategies. PMID:23202021

  14. Method and apparatus for measuring surface changes, in porous materials, using multiple differently-configured acoustic sensors

    DOEpatents

    Hietala, Susan Leslie; Hietala, Vincent Mark; Tigges, Chris Phillip

    2001-01-01

    A method and apparatus for measuring surface changes, such as mass uptake at various pressures, in a thin-film material, in particular porous membranes, using multiple differently-configured acoustic sensors.

  15. Failure monitoring of E-glass/vinylester composites using fiber grating acoustic sensor

    NASA Astrophysics Data System (ADS)

    Azmi, A. I.; Raju; Peng, G. D.

    2013-06-01

    This paper reports an application of an optical fiber sensor in a continuous and in situ failure testing of an E-glass/vinylester top hat stiffener (THS). The sensor head was constructed from a compact phase-shifted fiber Bragg grating (PS-FBG). The narrow transmission channel of the PS-FBG is highly sensitive to small perturbation, hence suitable to be used in acoustic emission (AE) assessment technique. The progressive failure of THS was tested under transverse loading to experimentally simulate the actual loading in practice. Our experimental tests have demonstrated, in good agreement with the commercial piezoelectric sensors, that the important failures information of the THS was successfully recorded by the simple intensity-type PS-FBG sensor.

  16. Acoustic emission source location on large plate-like structures using a local triangular sensor array

    NASA Astrophysics Data System (ADS)

    Aljets, Dirk; Chong, Alex; Wilcox, Steve; Holford, Karen

    2012-07-01

    A new acoustic emission (AE) source location method was developed for large plate-like structures, which evaluates the location of the source using a combined time of flight and modal source location algorithm. Three sensors are installed in a triangular array with a sensor to sensor distance of just a few centimeters. The direction from the sensor array to the AE source can be established by analysing the arrival times of the A0 component of the signal to the three sensors whilst the distance can be evaluated using the separation of S0 and A0 mode at each sensor respectively. The close positioning of the sensors allows the array to be installed in a single housing. This simplifies mounting, wiring and calibration procedures for non-destructive testing (NDT) and structural health monitoring (SHM) applications. Furthermore, this array could reduce the number of sensors needed to monitor large structures compared to other methods. An automatic wave mode identification method is also presented.

  17. A Finite Element Model of a MEMS-based Surface Acoustic Wave Hydrogen Sensor

    PubMed Central

    EL Gowini, Mohamed M.; Moussa, Walied A.

    2010-01-01

    Hydrogen plays a significant role in various industrial applications, but careful handling and continuous monitoring are crucial since it is explosive when mixed with air. Surface Acoustic Wave (SAW) sensors provide desirable characteristics for hydrogen detection due to their small size, low fabrication cost, ease of integration and high sensitivity. In this paper a finite element model of a Surface Acoustic Wave sensor is developed using ANSYS12© and tested for hydrogen detection. The sensor consists of a YZ-lithium niobate substrate with interdigital electrodes (IDT) patterned on the surface. A thin palladium (Pd) film is added on the surface of the sensor due to its high affinity for hydrogen. With increased hydrogen absorption the palladium hydride structure undergoes a phase change due to the formation of the β-phase, which deteriorates the crystal structure. Therefore with increasing hydrogen concentration the stiffness and the density are significantly reduced. The values of the modulus of elasticity and the density at different hydrogen concentrations in palladium are utilized in the finite element model to determine the corresponding SAW sensor response. Results indicate that with increasing the hydrogen concentration the wave velocity decreases and the attenuation of the wave is reduced. PMID:22205865

  18. Response of a Pt-polyyne membrane in surface acoustic wave sensors: Experimental and theoretical approach

    NASA Astrophysics Data System (ADS)

    Caliendo, Cinzia; Fratoddi, Ilaria; Russo, Maria Vittoria; Lo Sterzo, Claudio

    2003-06-01

    A surface acoustic wave (SAW) sensor, based on a polymeric sensitive membrane, has been realized for sensor applications and materials characterization. A platinum-containing rigid-rod organometallic polymer [-Pt(PPh3)2(-C≡C-pC6H2(2,5-OC16H33)2-C≡C-)]n (Pt-P-HDOB), obtained by the reaction of cis-[Pt(PPh3)2Cl2] with 1,4-diethynyl-2,5-dihexadeciloxybenzene (HDOB) by means of the recently assessed "Extended one pot" polymerization route, was here studied. The chemical structure and chain length of Pt-P-HDOB polymer were defined by spectroscopic techniques and gel permeation chromatography measurements. The acoustic characterization of the Pt-P-HDOB film was developed with the aid of the perturbation theory applied to different polymer-coated-piezoelectric substrates and the shear modulus of Pt-P-HDOB film have been estimated. A SAW delay line has been implemented on ZnO/Si substrate and a thin polymeric film has been spin deposited on the device surface to realize a chemical sensor. The sensor has been exposed to different chemicals and its response has been measured for different chemical concentrations. High sensitivity and reproducibility of the sensor response to relative humidity and methanol vapors were found.

  19. Particle velocity gradient based acoustic mode beamforming for short linear vector sensor arrays.

    PubMed

    Gur, Berke

    2014-06-01

    In this paper, a subtractive beamforming algorithm for short linear arrays of two-dimensional particle velocity sensors is described. The proposed method extracts the highly directional acoustic modes from the spatial gradients of the particle velocity field measured at closely spaced sensors along the array. The number of sensors in the array limits the highest order of modes that can be extracted. Theoretical analysis and numerical simulations indicate that the acoustic mode beamformer achieves directivity comparable to the maximum directivity that can be obtained with differential microphone arrays of equivalent aperture. When compared to conventional delay-and-sum beamformers for pressure sensor arrays, the proposed method achieves comparable directivity with 70%-85% shorter apertures. Moreover, the proposed method has additional capabilities such as high front-back (port-starboard) discrimination, frequency and steer direction independent response, and robustness to correlated ambient noise. Small inter-sensor spacing that results in very compact apertures makes the proposed beamformer suitable for space constrained applications such as hearing aids and short towed arrays for autonomous underwater platforms. PMID:24907810

  20. An adaptive OFDMA-based MAC protocol for underwater acoustic wireless sensor networks.

    PubMed

    Khalil, Issa M; Gadallah, Yasser; Hayajneh, Mohammad; Khreishah, Abdallah

    2012-01-01

    Underwater acoustic wireless sensor networks (UAWSNs) have many applications across various civilian and military domains. However, they suffer from the limited available bandwidth of acoustic signals and harsh underwater conditions. In this work, we present an Orthogonal Frequency Division Multiple Access (OFDMA)-based Media Access Control (MAC) protocol that is configurable to suit the operating requirements of the underwater sensor network. The protocol has three modes of operation, namely random, equal opportunity and energy-conscious modes of operation. Our MAC design approach exploits the multi-path characteristics of a fading acoustic channel to convert it into parallel independent acoustic sub-channels that undergo flat fading. Communication between node pairs within the network is done using subsets of these sub-channels, depending on the configurations of the active mode of operation. Thus, the available limited bandwidth gets fully utilized while completely avoiding interference. We derive the mathematical model for optimal power loading and subcarrier selection, which is used as basis for all modes of operation of the protocol. We also conduct many simulation experiments to evaluate and compare our protocol with other Code Division Multiple Access (CDMA)-based MAC protocols. PMID:23012517

  1. An Adaptive OFDMA-Based MAC Protocol for Underwater Acoustic Wireless Sensor Networks

    PubMed Central

    Khalil, Issa M.; Gadallah, Yasser; Hayajneh, Mohammad; Khreishah, Abdallah

    2012-01-01

    Underwater acoustic wireless sensor networks (UAWSNs) have many applications across various civilian and military domains. However, they suffer from the limited available bandwidth of acoustic signals and harsh underwater conditions. In this work, we present an Orthogonal Frequency Division Multiple Access (OFDMA)-based Media Access Control (MAC) protocol that is configurable to suit the operating requirements of the underwater sensor network. The protocol has three modes of operation, namely random, equal opportunity and energy-conscious modes of operation. Our MAC design approach exploits the multi-path characteristics of a fading acoustic channel to convert it into parallel independent acoustic sub-channels that undergo flat fading. Communication between node pairs within the network is done using subsets of these sub-channels, depending on the configurations of the active mode of operation. Thus, the available limited bandwidth gets fully utilized while completely avoiding interference. We derive the mathematical model for optimal power loading and subcarrier selection, which is used as basis for all modes of operation of the protocol. We also conduct many simulation experiments to evaluate and compare our protocol with other Code Division Multiple Access (CDMA)-based MAC protocols. PMID:23012517

  2. Delivery of Formulated Industrial Enzymes with Acoustic Technology.

    PubMed

    Hwang, Jennifer Dorcas; Ortiz-Maldonado, Mariliz; Paramonov, Sergey

    2016-02-01

    Industrial enzymes are instrumental in many applications, including carbohydrate processing, fabric and household care, biofuels, food, and animal nutrition, among others. Enzymes have to be active and stable not only in harsh application conditions, but also during shipment and storage. In protein stability studies, formulated concentrated enzyme solutions are frequently diluted gravimetrically prior to enzyme activity measurements, making it challenging to move toward more high-throughput techniques using conventional robotic equipment. Current assay methods pose difficulties when measuring highly concentrated proteins. For example, plastic pipette tips can introduce error because proteins adsorb to the tip surface, despite the presence of detergents, decreasing precision and overall efficiency of protein activity assays. Acoustic liquid handling technology, frequently used for various dilute small-molecule assays, may overcome such problems. Originally shown to effectively deliver dilute solutions of small molecules, this technology is used here as an effective alternative to the aforementioned challenge with viscous concentrated protein solutions. Because the acoustic liquid handler transfers nanoliter quantities of liquids without using pipette tips and without sample loss, it rapidly and uniformly prepares assay plates for enzyme activity measurements within minutes. This increased efficiency transforms the nature of enzyme stability studies toward high precision and throughput. PMID:26169023

  3. High performance distributed acoustic sensor using cyclic pulse coding in a direct detection coherent-OTDR

    NASA Astrophysics Data System (ADS)

    Muanenda, Yonas; Oton, Claudio J.; Faralli, Stefano; Di Pasquale, Fabrizio

    2015-07-01

    We propose and experimentally demonstrate a Distributed Acoustic Sensor exploiting cyclic Simplex coding in a phase-sensitive OTDR on standard single mode fibers based on direct detection. Suitable design of the source and use of cyclic coding is shown to improve the SNR of the coherent back-scattered signal by up to 9 dB, reducing fading due to modulation instability and enabling accurate long-distance measurement of vibrations with minimal post-processing.

  4. Dual fiber Bragg gratings configuration-based fiber acoustic sensor for low-frequency signal detection

    NASA Astrophysics Data System (ADS)

    Yang, Dong; Wang, Shun; Lu, Ping; Liu, Deming

    2014-11-01

    We propose and fabricate a new type fiber acoustic sensor based on dual fiber Bragg gratings (FBGs) configuration. The acoustic sensor head is constructed by putting the sensing cells enclosed in an aluminum cylinder space built by two Cband FBGs and a titanium diaphragm of 50 um thickness. One end of each FBG is longitudinally adhered to the diaphragm by UV glue. Both of the two FBGs are employed for reflecting light. The dual FBGs play roles not only as signal transmission system but also as sensing component, and they demodulate each other's optical signal mutually during the measurement. Both of the two FBGs are pre-strained and the output optical power experiences fluctuation in a linear relationship along with a variation of axial strain and surrounding acoustic interference. So a precise approach to measure the frequency and sound pressure of the acoustic disturbance is achieved. Experiments are performed and results show that a relatively flat frequency response in a range from 200 Hz to 1 kHz with the average signal-to-noise ratio (SNR) above 21 dB is obtained. The maximum sound pressure sensitivity of 11.35mV/Pa is achieved with the Rsquared value of 0.99131 when the sound pressure in the range of 87.7-106.6dB. It has potential applications in low frequency signal detection. Owing to its direct self-demodulation method, the sensing system reveals the advantages of easy to demodulate, good temperature stability and measurement reliability. Besides, performance of the proposed sensor could be improved by optimizing the parameters of the sensor, especially the diaphragm.

  5. AURP: an AUV-aided underwater routing protocol for underwater acoustic sensor networks.

    PubMed

    Yoon, Seokhoon; Azad, Abul K; Oh, Hoon; Kim, Sunghwan

    2012-01-01

    Deploying a multi-hop underwater acoustic sensor network (UASN) in a large area brings about new challenges in reliable data transmissions and survivability of network due to the limited underwater communication range/bandwidth and the limited energy of underwater sensor nodes. In order to address those challenges and achieve the objectives of maximization of data delivery ratio and minimization of energy consumption of underwater sensor nodes, this paper proposes a new underwater routing scheme, namely AURP (AUV-aided underwater routing protocol), which uses not only heterogeneous acoustic communication channels but also controlled mobility of multiple autonomous underwater vehicles (AUVs). In AURP, the total data transmissions are minimized by using AUVs as relay nodes, which collect sensed data from gateway nodes and then forward to the sink. Moreover, controlled mobility of AUVs makes it possible to apply a short-range high data rate underwater channel for transmissions of a large amount of data. To the best to our knowledge, this work is the first attempt to employ multiple AUVs as relay nodes in a multi-hop UASN to improve the network performance in terms of data delivery ratio and energy consumption. Simulations, which are incorporated with a realistic underwater acoustic communication channel model, are carried out to evaluate the performance of the proposed scheme, and the results indicate that a high delivery ratio and low energy consumption can be achieved. PMID:22438740

  6. AURP: An AUV-Aided Underwater Routing Protocol for Underwater Acoustic Sensor Networks

    PubMed Central

    Yoon, Seokhoon; Azad, Abul K.; Oh, Hoon; Kim, Sunghwan

    2012-01-01

    Deploying a multi-hop underwater acoustic sensor network (UASN) in a large area brings about new challenges in reliable data transmissions and survivability of network due to the limited underwater communication range/bandwidth and the limited energy of underwater sensor nodes. In order to address those challenges and achieve the objectives of maximization of data delivery ratio and minimization of energy consumption of underwater sensor nodes, this paper proposes a new underwater routing scheme, namely AURP (AUV-aided underwater routing protocol), which uses not only heterogeneous acoustic communication channels but also controlled mobility of multiple autonomous underwater vehicles (AUVs). In AURP, the total data transmissions are minimized by using AUVs as relay nodes, which collect sensed data from gateway nodes and then forward to the sink. Moreover, controlled mobility of AUVs makes it possible to apply a short-range high data rate underwater channel for transmissions of a large amount of data. To the best to our knowledge, this work is the first attempt to employ multiple AUVs as relay nodes in a multi-hop UASN to improve the network performance in terms of data delivery ratio and energy consumption. Simulations, which are incorporated with a realistic underwater acoustic communication channel model, are carried out to evaluate the performance of the proposed scheme, and the results indicate that a high delivery ratio and low energy consumption can be achieved. PMID:22438740

  7. Development of a Multi-Channel Piezoelectric Acoustic Sensor Based on an Artificial Basilar Membrane

    PubMed Central

    Jung, Youngdo; Kwak, Jun-Hyuk; Lee, Young Hwa; Kim, Wan Doo; Hur, Shin

    2014-01-01

    In this research, we have developed a multi-channel piezoelectric acoustic sensor (McPAS) that mimics the function of the natural basilar membrane capable of separating incoming acoustic signals mechanically by their frequency and generating corresponding electrical signals. The McPAS operates without an external energy source and signal processing unit with a vibrating piezoelectric thin film membrane. The shape of the vibrating membrane was chosen to be trapezoidal such that different locations of membrane have different local resonance frequencies. The length of the membrane is 28 mm and the width of the membrane varies from 1 mm to 8 mm. Multiphysics finite element analysis (FEA) was carried out to predict and design the mechanical behaviors and piezoelectric response of the McPAS model. The designed McPAS was fabricated with a MEMS fabrication process based on the simulated results. The fabricated device was tested with a mouth simulator to measure its mechanical and piezoelectrical frequency response with a laser Doppler vibrometer and acoustic signal analyzer. The experimental results show that the as fabricated McPAS can successfully separate incoming acoustic signals within the 2.5 kHz–13.5 kHz range and the maximum electrical signal output upon acoustic signal input of 94 dBSPL was 6.33 mVpp. The performance of the fabricated McPAS coincided well with the designed parameters. PMID:24361926

  8. A radar-enabled collaborative sensor network integrating COTS technology for surveillance and tracking.

    PubMed

    Kozma, Robert; Wang, Lan; Iftekharuddin, Khan; McCracken, Ernest; Khan, Muhammad; Islam, Khandakar; Bhurtel, Sushil R; Demirer, R Murat

    2012-01-01

    The feasibility of using Commercial Off-The-Shelf (COTS) sensor nodes is studied in a distributed network, aiming at dynamic surveillance and tracking of ground targets. Data acquisition by low-cost (<$50 US) miniature low-power radar through a wireless mote is described. We demonstrate the detection, ranging and velocity estimation, classification and tracking capabilities of the mini-radar, and compare results to simulations and manual measurements. Furthermore, we supplement the radar output with other sensor modalities, such as acoustic and vibration sensors. This method provides innovative solutions for detecting, identifying, and tracking vehicles and dismounts over a wide area in noisy conditions. This study presents a step towards distributed intelligent decision support and demonstrates effectiveness of small cheap sensors, which can complement advanced technologies in certain real-life scenarios. PMID:22438713

  9. A Radar-Enabled Collaborative Sensor Network Integrating COTS Technology for Surveillance and Tracking

    PubMed Central

    Kozma, Robert; Wang, Lan; Iftekharuddin, Khan; McCracken, Ernest; Khan, Muhammad; Islam, Khandakar; Bhurtel, Sushil R.; Demirer, R. Murat

    2012-01-01

    The feasibility of using Commercial Off-The-Shelf (COTS) sensor nodes is studied in a distributed network, aiming at dynamic surveillance and tracking of ground targets. Data acquisition by low-cost (<$50 US) miniature low-power radar through a wireless mote is described. We demonstrate the detection, ranging and velocity estimation, classification and tracking capabilities of the mini-radar, and compare results to simulations and manual measurements. Furthermore, we supplement the radar output with other sensor modalities, such as acoustic and vibration sensors. This method provides innovative solutions for detecting, identifying, and tracking vehicles and dismounts over a wide area in noisy conditions. This study presents a step towards distributed intelligent decision support and demonstrates effectiveness of small cheap sensors, which can complement advanced technologies in certain real-life scenarios. PMID:22438713

  10. A wireless demodulation system for passive surface acoustic wave torque sensor

    NASA Astrophysics Data System (ADS)

    Ji, Xiaojun; Fan, Yanping; Qi, Hongli; Chen, Jing; Han, Tao; Cai, Ping

    2014-12-01

    Surface acoustic wave (SAW) resonators are utilized as torque sensors for their passive and wireless features. However, the response of a SAW torque sensor is difficult to detect because of the transient response duration and interruption of channel noise, which limit the application of SAW torque sensors. The sensitive mechanism and response function of a passive wireless SAW torque sensor are analyzed in this study. A novel demodulation system involving both hardware and software is developed for the SAW torque sensor. A clipping amplifier is utilized in the hardware to widen the dynamic response range and increase the length of the valid signal. Correlation extension and centroid algorithms are designed to lengthen the received signal and improve the estimation accuracy of the center frequency of the response signal, respectively. Meanwhile, a fast binary search algorithm is proposed to accelerate the scanning cycle according to the developed response function. Finally, the SAW torque sensor demodulation system is set up and SAW resonators with high sensitivity are fabricated on a quartz substrate. The presented demodulation system is tested, and a standard deviation of 0.28 kHz is achieved. This value is much smaller than that of classic and modern spectrum estimation methods. The sensitivity of resonance frequency shift versus torque on the shaft of the assembled senor is 2.03 kHz/Nm; the coefficient of determination is 0.999, and the linearity is 0.87%. Experimental results verify the validity and feasibility of the proposed SAW torque sensor demodulation system.

  11. Applying Digital Sensor Technology: A Problem-Solving Approach

    ERIC Educational Resources Information Center

    Seedhouse, Paul; Knight, Dawn

    2016-01-01

    There is currently an explosion in the number and range of new devices coming onto the technology market that use digital sensor technology to track aspects of human behaviour. In this article, we present and exemplify a three-stage model for the application of digital sensor technology in applied linguistics that we have developed, namely,…

  12. Acoustic detection and localization of weapons fire by unattended ground sensors and aerostat-borne sensors

    NASA Astrophysics Data System (ADS)

    Naz, P.; Marty, Ch.; Hengy, S.; Miller, L. S.

    2009-05-01

    The detection and localization of artillery guns on the battlefield is envisaged by means of acoustic and seismic waves. The main objective of this work is to examine the different frequency ranges usable for the detection of small arms, mortars, and artillery guns on the same hardware platform. The main stages of this study have consisted of: data acquisition of the acoustic signals of the different weapons used, signal processing and evaluation of the localization performance for various types of individual arrays, and modeling of the wave propagation in the atmosphere. The study of the propagation effects on the signatures of these weapons is done by comparing the acoustic signals measured during various days, at ground level and at the altitude of our aerostat (typically 200 m). Numerical modeling has also been performed to reinforce the interpretation of the experimental results.

  13. Algorithm for heart rate extraction in a novel wearable acoustic sensor

    PubMed Central

    Imtiaz, Syed Anas; Aguilar–Pelaez, Eduardo; Rodriguez–Villegas, Esther

    2015-01-01

    Phonocardiography is a widely used method of listening to the heart sounds and indicating the presence of cardiac abnormalities. Each heart cycle consists of two major sounds – S1 and S2 – that can be used to determine the heart rate. The conventional method of acoustic signal acquisition involves placing the sound sensor at the chest where this sound is most audible. Presented is a novel algorithm for the detection of S1 and S2 heart sounds and the use of them to extract the heart rate from signals acquired by a small sensor placed at the neck. This algorithm achieves an accuracy of 90.73 and 90.69%, with respect to heart rate value provided by two commercial devices, evaluated on more than 38 h of data acquired from ten different subjects during sleep in a pilot clinical study. This is the largest dataset for acoustic heart sound classification and heart rate extraction in the literature to date. The algorithm in this study used signals from a sensor designed to monitor breathing. This shows that the same sensor and signal can be used to monitor both breathing and heart rate, making it highly useful for long-term wearable vital signs monitoring. PMID:26609401

  14. Surface acoustic wave acceleration sensor with high sensitivity incorporating ST-X quartz cantilever beam

    NASA Astrophysics Data System (ADS)

    Wang, Wen; Huang, Yangqing; Liu, Xinlu; Liang, Yong

    2015-01-01

    The implementation and performance of a surface acoustic wave (SAW)-based acceleration sensor is described. The sensor was composed of a flexible ST-X quartz cantilever beam with a relatively substantial proof mass at the undamped end, a pattern of a two-port SAW resonator deposited directly on the surface of the beam adjacent to the clamped end for maximum strain sensitivity and a SAW resonator affixed on the metal package base for temperature compensation. The acceleration was directed to the proof mass flex of the cantilever, inducing relative changes in the acoustic propagation characteristics of the SAW traveling along the beams. The frequency signal from the differential oscillation structure utilizing the SAW resonators as the feedback element varies as a function of acceleration. The sensor response mechanism was analyzed theoretically, with the aim of determining the optimized dimension of the cantilever beam. The coupling of modes (COM) model was used to simulate the synchronous SAW resonator prior to fabrication. The oscillator frequency stability was improved using the phase modulation approach; the obtained typical short-term frequency stability ranged up to 1 Hz s-1. The performance of the developed acceleration sensor was evaluated using the precise vibration table and was also evaluated in comparison to the theoretical calculation. A high frequency sensitivity of 29.7 kHz g-1, good linearity and a lower detection limit (˜1 × 10-4 g) were achieved in the measured results.

  15. A new sensor technology for 2D ultrasound-guided needle tracking.

    PubMed

    Lu, Huanxiang; Li, Junbo; Lu, Qiang; Bharat, Shyam; Erkamp, Ramon; Chen, Bin; Drysdale, Jeremy; Vignon, Francois; Jain, Ameet

    2014-01-01

    2D Ultrasound (US) is becoming the preferred modality for image-guided interventions due to its low cost and portability. However, the main limitation is the limited visibility of surgical tools. We present a new sensor technology that can easily be embedded on needles that are used for US-guided interventions. Two different types of materials are proposed to be used as sensor--co-polymer and PZT. The co-polymer technology is particularly attractive due to its plasticity, allowing very thin depositions (10-20 μm) on a variety of needle shapes. Both sensors receive acoustic energy and convert it to an electrical signal. The precise location of the needle can then be estimated from this signal, to provide real-time feedback to the clinician. We evaluated the feasibility of this new technology using (i) a 4DOF robot in a water tank; (ii) extensive ex vivo experiments; and (iii) in vivo studies. Quantitative robotic studies indicated that the co-polymer is more robust and stable when compared to PZT. In quantitative experiments, the technology achieved a tracking accuracy of 0.14 ± 0.03mm, significantly superior to competing technologies. The technology also proved success in near-real clinical studies on tissue data. This sensor technology is non-disruptive of existing clinical workflows, highly accurate, and is cost-effective. Initial clinician feedback shows great potential for large scale clinical impact. PMID:25485403

  16. The Nature of Exhibits about Acoustics in Science and Technology Centres

    ERIC Educational Resources Information Center

    Afonso, Ana S.; Gilbert, John K.

    2008-01-01

    This is a study of the opportunities currently provided by interactive science and technology centres for visitors' engagement in the field of acoustics. E-mails, requesting a description of exhibits on acoustics (sound and hearing) in use, were sent to members of staff of interactive science and technology centres around the world as well as to…

  17. Surface acoustic waves/silicon monolithic sensor processor

    NASA Technical Reports Server (NTRS)

    Kowel, S. T.; Kornreich, P. G.; Fathimulla, M. A.; Mehter, E. A.

    1981-01-01

    Progress is reported in the creation of a two dimensional Fourier transformer for optical images based on the zinc oxide on silicon technology. The sputtering of zinc oxide films using a micro etch system and the possibility of a spray-on technique based on zinc chloride dissolved in alcohol solution are discussed. Refinements to techniques for making platinum silicide Schottky barrier junctions essential for constructing the ultimate convolver structure are described.

  18. Response Mechanism for Surface Acoustic Wave Gas Sensors Based on Surface-Adsorption

    PubMed Central

    Liu, Jiansheng; Lu, Yanyan

    2014-01-01

    A theoretical model is established to describe the response mechanism of surface acoustic wave (SAW) gas sensors based on physical adsorption on the detector surface. Wohljent's method is utilized to describe the relationship of sensor output (frequency shift of SAW oscillator) and the mass loaded on the detector surface. The Brunauer-Emmett-Teller (BET) formula and its improved form are introduced to depict the adsorption behavior of gas on the detector surface. By combining the two methods, we obtain a theoretical model for the response mechanism of SAW gas sensors. By using a commercial SAW gas chromatography (GC) analyzer, an experiment is performed to measure the frequency shifts caused by different concentration of dimethyl methylphosphonate (DMMP). The parameters in the model are given by fitting the experimental results and the theoretical curve agrees well with the experimental data. PMID:24743157

  19. Structural Acoustic Prediction and Interior Noise Control Technology

    NASA Technical Reports Server (NTRS)

    Mathur, G. P.; Chin, C. L.; Simpson, M. A.; Lee, J. T.; Palumbo, Daniel L. (Technical Monitor)

    2001-01-01

    This report documents the results of Task 14, "Structural Acoustic Prediction and Interior Noise Control Technology". The task was to evaluate the performance of tuned foam elements (termed Smart Foam) both analytically and experimentally. Results taken from a three-dimensional finite element model of an active, tuned foam element are presented. Measurements of sound absorption and sound transmission loss were taken using the model. These results agree well with published data. Experimental performance data were taken in Boeing's Interior Noise Test Facility where 12 smart foam elements were applied to a 757 sidewall. Several configurations were tested. Noise reductions of 5-10 dB were achieved over the 200-800 Hz bandwidth of the controller. Accelerometers mounted on the panel provided a good reference for the controller. Configurations with far-field error microphones outperformed near-field cases.

  20. High-sensitivity open-loop electronics for gravimetric acoustic-wave-based sensors.

    PubMed

    Rabus, David; Friedt, Jean-Michel; Ballandras, Sylvain; Martin, Gilles; Carry, Emile; Blondeau-Patissier, Virginie

    2013-06-01

    Detecting chemical species in gas phase has recently received an increasing interest mainly for security control, trying to implement new systems allowing for extended dynamics and reactivity. In this work, an open-loop interrogation strategy is proposed to use radio-frequency acoustic transducers as micro-balances for that purpose. The resulting system is dedicated to the monitoring of chemical compounds in gaseous or liquid-phase state. A 16 Hz standard deviation is demonstrated at 125 MHz, with a working frequency band in the 60 to 133 MHz range, answering the requirements for using Rayleigh- and Love-wave-based delay lines operating with 40-μm acoustic wavelength transducers. Moreover, this electronic setup was used to interrogate a high-overtone bulk acoustic wave resonator (HBAR) microbalance, a new sensor class allowing for multi-mode interrogation for gravimetric measurement improvement. The noise source still limiting the system performance is due to the analog-to-digital converter of the microcontroller, thus leaving open degrees-of-freedom for improving the obtained results by optimizing the voltage reference and board layout. The operation of the system is illustrated using a calibrated galvanic deposition at the surface of Love-wave delay lines to assess theoretical predictions of their gravimetric sensitivity and to compare them with HBAR-based sensor sensitivity. PMID:25004485

  1. Monitoring Anthropogenic Ocean Sound from Shipping Using an Acoustic Sensor Network and a Compressive Sensing Approach.

    PubMed

    Harris, Peter; Philip, Rachel; Robinson, Stephen; Wang, Lian

    2016-01-01

    Monitoring ocean acoustic noise has been the subject of considerable recent study, motivated by the desire to assess the impact of anthropogenic noise on marine life. A combination of measuring ocean sound using an acoustic sensor network and modelling sources of sound and sound propagation has been proposed as an approach to estimating the acoustic noise map within a region of interest. However, strategies for developing a monitoring network are not well established. In this paper, considerations for designing a network are investigated using a simulated scenario based on the measurement of sound from ships in a shipping lane. Using models for the sources of the sound and for sound propagation, a noise map is calculated and measurements of the noise map by a sensor network within the region of interest are simulated. A compressive sensing algorithm, which exploits the sparsity of the representation of the noise map in terms of the sources, is used to estimate the locations and levels of the sources and thence the entire noise map within the region of interest. It is shown that although the spatial resolution to which the sound sources can be identified is generally limited, estimates of aggregated measures of the noise map can be obtained that are more reliable compared with those provided by other approaches. PMID:27011187

  2. Characterization of polymeric surface acoustic wave sensor coatings and semiempirical models of sensor responses to organic vapors.

    PubMed

    Patrash, S J; Zellers, E T

    1993-08-01

    Responses from an array of four polymer-coated surface acoustic wave sensors exposed to a series of 39 organic vapors were used to investigate sensor response models based on vapor boiling point, solubility parameters, and solvation parameters in conjunction with linear solvation energy relationships. As part of this effort, sensor response data were used to estimate the solubility parameters and solvation parameters of the sensor coatings by adaptation of methods originally developed for use with gas-liquid chromatographic retention data. Values of these parameters were found to be consistent with the structures of the coatings though in some cases different from those determined by other methods. Discrepancies were attributed to differences in the conditions used for the determinations. Sensor responses were linear over the concentration ranges examined and could be summarized using the empirically determined partition coefficient, Ke, for each vapor-coating pair. Linear correlations were found between log Ke and vapor boiling point, and the slopes of the regressions lines were similar to those expected for ideal behavior. The strength of the correlations decreased with increasing coating polarity, and it was necessary to divide the vapors into two or three broad chemical classes in order to obtain satisfactory results. Improved correlations were found by use of Hildebrand solubility parameters in a model based on regular solution theory which attempts to account for nonideal vapor-coating interactions. The use of solvation parameters in linear solvation energy relationships, however, provided the strongest correlations, with modeled K values falling within a factor of 2 of experimental values in all cases and within +/- 25% of experimental values in 83% of the cases. Application of these models to the prediction of sensor array response patterns appears promising. PMID:8372969

  3. Harsh Environment Silicon Carbide Sensor Technology for Geothermal Instrumentation

    SciTech Connect

    Pisano, Albert P.

    2013-04-26

    This project utilizes Silicon Carbide (SiC) materials platform to fabricate advanced sensors to be used as high-temperature downhole instrumentation for the DOE’s Geothermal Technologies Program on Enhanced Geothermal Systems. The scope of the proposed research is to 1) develop a SiC pressure sensor that can operate in harsh supercritical conditions, 2) develop a SiC temperature sensor that can operate in harsh supercritical conditions, 3) develop a bonding process for adhering SiC sensor die to well casing couplers, and 4) perform experimental exposure testing of sensor materials and the sensor devices.

  4. A lateral field excited (yxl)88° LiTaO3 bulk acoustic wave sensor with interdigital electrodes.

    PubMed

    Ma, Tingfeng; Wang, Ji; Du, Jianke; Yuan, Lili; Qian, Zhenghua; Zhang, Zhitian; Zhang, Chao

    2013-03-01

    In this work, to improve the sensitivity of lateral field excited (LFE) sensors to changes of liquid conductivity, LFE bulk acoustic wave sensors with interdigital electrodes are investigated. LFE bulk acoustic wave on thickness-shear mode is excited successfully by interdigital electrodes on (yxl)88° LiTaO(3) and applied in liquid-phase sensor. The electric field direction of LFE (yxl)88° LiTaO(3) plates is determined. Based on this, several LFE bulk acoustic wave sensors with interdigital electrodes are designed and fabricated to increase the sensitivity of LiTaO(3) LFE sensors. The results show that the (yxl)88° LiTaO(3) LFE sensor with interdigital electrodes is 10.9 times and 2.1 times more sensitive to changes in liquid conductivity compared to traditional LFE devices with single gap circular electrodes and Archimedes spiral electrodes, respectively. The results are important for investigating high-sensitivity LFE bulk acoustic wave sensors by using LiTaO(3) crystal. PMID:23339996

  5. Robust Distributed Noise Reduction in Hearing Aids with External Acoustic Sensor Nodes

    NASA Astrophysics Data System (ADS)

    Bertrand, Alexander; Moonen, Marc

    2009-12-01

    The benefit of using external acoustic sensor nodes for noise reduction in hearing aids is demonstrated in a simulated acoustic scenario with multiple sound sources. A distributed adaptive node-specific signal estimation (DANSE) algorithm, that has a reduced communication bandwidth and computational load, is evaluated. Batch-mode simulations compare the noise reduction performance of a centralized multi-channel Wiener filter (MWF) with DANSE. In the simulated scenario, DANSE is observed not to be able to achieve the same performance as its centralized MWF equivalent, although in theory both should generate the same set of filters. A modification to DANSE is proposed to increase its robustness, yielding smaller discrepancy between the performance of DANSE and the centralized MWF. Furthermore, the influence of several parameters such as the DFT size used for frequency domain processing and possible delays in the communication link between nodes is investigated.

  6. Optimization of Capacitive Acoustic Resonant Sensor Using Numerical Simulation and Design of Experiment

    PubMed Central

    Haque, Rubaiyet Iftekharul; Loussert, Christophe; Sergent, Michelle; Benaben, Patrick; Boddaert, Xavier

    2015-01-01

    Optimization of the acoustic resonant sensor requires a clear understanding of how the output responses of the sensor are affected by the variation of different factors. During this work, output responses of a capacitive acoustic transducer, such as membrane displacement, quality factor, and capacitance variation, are considered to evaluate the sensor design. The six device parameters taken into consideration are membrane radius, backplate radius, cavity height, air gap, membrane tension, and membrane thickness. The effects of factors on the output responses of the transducer are investigated using an integrated methodology that combines numerical simulation and design of experiments (DOE). A series of numerical experiments are conducted to obtain output responses for different combinations of device parameters using finite element methods (FEM). Response surface method is used to identify the significant factors and to develop the empirical models for the output responses. Finally, these results are utilized to calculate the optimum device parameters using multi-criteria optimization with desirability function. Thereafter, the validating experiments are designed and deployed using the numerical simulation to crosscheck the responses. PMID:25894937

  7. Acoustic emission detection in carbon composite materials using Fiber Bragg Grating optical sensors

    NASA Astrophysics Data System (ADS)

    Mabry, Nehemiah J.

    In light of ongoing efforts to reduce weight but maintain durability, designers have examined the use of carbon fiber reinforced polymer (CFRP) composite materials for a number of aerospace and civil structures. Along with this research has been the study of determining reliable sensing and monitoring capabilities to avoid catastrophic failure. Fiber Bragg Grating (FBG) sensors are known to carry several advantages in this area, one of which is their proven ability to detect acoustic emission (AE) Lamb waves in composite structures. AE is produced in these materials by failure mechanisms such as resin cracking, fiber debonding, fiber pullout and fiber breakage. In this study FBG sensors were attached to CFRP laminates to detect acoustic emission events. Also Felicity Ratio (FR) measurements were made as they accumulated damage. FR is obtained directly from the ratio of the stress level at the onset of significant emission versus the maximum prior stress at the same AE level. The main objective of this paper is to describe the results of acousto-optic experiments using FBG sensors and present it as a way of determining accumulated damage in a carbon composite structure.

  8. Optimization of capacitive acoustic resonant sensor using numerical simulation and design of experiment.

    PubMed

    Haque, Rubaiyet Iftekharul; Loussert, Christophe; Sergent, Michelle; Benaben, Patrick; Boddaert, Xavier

    2015-01-01

    Optimization of the acoustic resonant sensor requires a clear understanding of how the output responses of the sensor are affected by the variation of different factors. During this work, output responses of a capacitive acoustic transducer, such as membrane displacement, quality factor, and capacitance variation, are considered to evaluate the sensor design. The six device parameters taken into consideration are membrane radius, backplate radius, cavity height, air gap, membrane tension, and membrane thickness. The effects of factors on the output responses of the transducer are investigated using an integrated methodology that combines numerical simulation and design of experiments (DOE). A series of numerical experiments are conducted to obtain output responses for different combinations of device parameters using finite element methods (FEM). Response surface method is used to identify the significant factors and to develop the empirical models for the output responses. Finally, these results are utilized to calculate the optimum device parameters using multi-criteria optimization with desirability function. Thereafter, the validating experiments are designed and deployed using the numerical simulation to crosscheck the responses. PMID:25894937

  9. Smart DNA Fabrication Using Sound Waves: Applying Acoustic Dispensing Technologies to Synthetic Biology.

    PubMed

    Kanigowska, Paulina; Shen, Yue; Zheng, Yijing; Rosser, Susan; Cai, Yizhi

    2016-02-01

    Acoustic droplet ejection (ADE) technology uses focused acoustic energy to transfer nanoliter-scale liquid droplets with high precision and accuracy. This noncontact, tipless, low-volume dispensing technology minimizes the possibility of cross-contamination and potentially reduces the costs of reagents and consumables. To date, acoustic dispensers have mainly been used in screening libraries of compounds. In this paper, we describe the first application of this powerful technology to the rapidly developing field of synthetic biology, for DNA synthesis and assembly at the nanoliter scale using a Labcyte Echo 550 acoustic dispenser. We were able to successfully downscale PCRs and the popular one-pot DNA assembly methods, Golden Gate and Gibson assemblies, from the microliter to the nanoliter scale with high assembly efficiency, which effectively cut the reagent cost by 20- to 100-fold. We envision that acoustic dispensing will become an instrumental technology in synthetic biology, in particular in the era of DNA foundries. PMID:26163567

  10. Development of Sensors and Sensing Technology for Hydrogen Fuel Cell Vehicle Applications

    SciTech Connect

    Brosha, E L; Sekhar, P K; Mukundan, R; Williamson, T; Garzon, F H; Woo, L Y; Glass, R R

    2010-01-06

    One related area of hydrogen fuel cell vehicle (FCV) development that cannot be overlooked is the anticipated requirement for new sensors for both the monitoring and control of the fuel cell's systems and for those devices that will be required for safety. Present day automobiles have dozens of sensors on-board including those for IC engine management/control, sensors for state-of-health monitoring/control of emissions systems, sensors for control of active safety systems, sensors for triggering passive safety systems, and sensors for more mundane tasks such as fluids level monitoring to name the more obvious. The number of sensors continues to grow every few years as a result of safety mandates but also in response to consumer demands for new conveniences and safety features. Some of these devices (e.g. yaw sensors for dynamic stability control systems or tire presure warning RF-based devices) may be used on fuel cell vehicles without any modification. However the use of hydrogen as a fuel will dictate the development of completely new technologies for such requirements as the detection of hydrogen leaks, sensors and systems to continuously monitor hydrogen fuel purity and protect the fuel cell stack from poisoning, and for the important, yet often taken for granted, tasks such as determining the state of charge of the hydrogen fuel storage and delivery system. Two such sensors that rely on different transduction mechanisms will be highlighted in this presentation. The first is an electrochemical device for monitoring hydrogen levels in air. The other technology covered in this work, is an acoustic-based approach to determine the state of charge of a hydride storage system.

  11. #2) Sensor Technology-State of the Science

    EPA Science Inventory

    Establish market surveys of commercially-available air quality sensorsConduct an extensive literature survey describing the state of sensor technologiesInvestigate emerging technologies and their potential to meet future air quality monitoring needs for the Agency as well as othe...

  12. An Amplitude-Based Estimation Method for International Space Station (ISS) Leak Detection and Localization Using Acoustic Sensor Networks

    NASA Technical Reports Server (NTRS)

    Tian, Jialin; Madaras, Eric I.

    2009-01-01

    The development of a robust and efficient leak detection and localization system within a space station environment presents a unique challenge. A plausible approach includes the implementation of an acoustic sensor network system that can successfully detect the presence of a leak and determine the location of the leak source. Traditional acoustic detection and localization schemes rely on the phase and amplitude information collected by the sensor array system. Furthermore, the acoustic source signals are assumed to be airborne and far-field. Likewise, there are similar applications in sonar. In solids, there are specialized methods for locating events that are used in geology and in acoustic emission testing that involve sensor arrays and depend on a discernable phase front to the received signal. These methods are ineffective if applied to a sensor detection system within the space station environment. In the case of acoustic signal location, there are significant baffling and structural impediments to the sound path and the source could be in the near-field of a sensor in this particular setting.

  13. ZnO nanomaterials based surface acoustic wave ethanol gas sensor.

    PubMed

    Wu, Y; Li, X; Liu, J H; He, Y N; Yu, L M; Liu, W H

    2012-08-01

    ZnO nanomaterials based surface acoustic wave (SAW) gas sensor has been investigated in ethanol environment at room temperature. The ZnO nanomaterials have been prepared through thermal evaporation of high-purity zinc powder. The as-prepared ZnO nanomaterials have been characterized with scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray Diffraction (XRD) techniques. The results indicate that the obtained ZnO nanomaterials, including many types of nanostructures such as nanobelts, nanorods, nanowires as well as nanosheets, are wurtzite with hexagonal structure and well-crystallized. The SAW sensor coated with the nanostructured ZnO materials has been tested in ethanol gas of various concentrations at room temperature. A network analyzer is used to monitor the change of the insertion loss of the SAW sensor when exposed to ethanol gas. The insertion loss of the SAW sensor varies significantly with the change of ethanol concentration. The experimental results manifest that the ZnO nanomaterials based SAW ethanol gas sensor exhibits excellent sensitivity and good short-term reproducibility at room temperature. PMID:22962774

  14. Underwater acoustic sensor networks: Medium access control, routing and reliable transfer

    NASA Astrophysics Data System (ADS)

    Xie, Peng

    Recently there have been growing interests in monitoring aquatic environments for scientific exploration, commercial exploitation and coastline protection. The ideal vehicle for this type of extensive monitoring is a mobile underwater sensor network (M-UWSN), consisting of a large number of low cost underwater sensors that can move with water currents and dispersion. M-UWSNs are significantly different from terrestrial sensor networks: (1) Radio channels do not work well under water. They must be replaced by acoustic channels, which feature long propagation delays, low communication bandwidth and high channel error rates; (2) While most ground sensors are static, underwater sensor nodes may move with water currents (and other underwater activities), as introduces passive sensor mobility. Due to the very different environment properties and the unique characteristics of acoustic channels, the protocols developed for terrestrial sensor networks are not applicable to M-UWSNs, and new research at every level of the protocol suite is demanded. In this dissertation work, we investigate three fundamental networking problems in M-UWSN design: medium access control, multi-hop routing and reliable data transfer. (1) Medium access control (MAC): the long propagation delays and narrow communication bandwidth of acoustic channels pose the major challenges to the energy-efficient MAC design in M-UWSNs. For the first time, we formally investigate the random access and RTS/CTS techniques in networks with long propagation delays and low communication bandwidth (as in M-UWSNs). Based on this study, we propose a novel reservation-based MAC approach, called R-MAC, for dense underwater sensor networks with unevenly distributed (spatially and temporally) traffic. Simulation results show that R-MAC is not only energy efficient but also supports fairness. (2) Multi-hop routing: In M-UWSNs, energy efficiency and mobility handling are the two major concerns for multi-hop routing, which have

  15. Enhanced Sensitive Love Wave Surface Acoustic Wave Sensor Designed for Immunoassay Formats

    PubMed Central

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

    2015-01-01

    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. PMID:25951337

  16. Integrated acoustic emission/vibration sensor for detecting damage in aircraft drive train components

    NASA Astrophysics Data System (ADS)

    Godínez-Azcuaga, Valery F.; Ozevin, Didem; Finlayson, Richard D.; Anastasopoulos, Athanasios; Tsimogiannis, Apostolos

    2007-04-01

    Diaphragm-type couplings are high misalignment torque and speed transfer components used in aircrafts. Crack development in such couplings, or in the drive train in general, can lead to component failure that can bring down an aircraft. Real time detection of crack formation and growth is important to prevent such catastrophic failures. However, there is no single Nondestructive Monitoring method available that is capable of assessing the early stages of crack growth in such components. While vibration based damage identification techniques are used, they cannot detect cracks until they reach a considerable size, which makes detection of the onset of cracking extremely difficult. Acoustic Emission (AE) can detect and monitor early stage crack growth, however excessive background noise can mask acoustic emissions produced by crack initiation. Fusion of the two mentioned techniques can increase the accuracy of measurement and minimize false alarms. However, a monitoring system combining both techniques could prove too large and heavy for the already restricted space available in aircrafts. In the present work, we will present a newly developed integrated Acoustic Emission/Vibration (AE/VIB) combined sensor which can operate in the temperature range of -55°F to 257°F and in high EMI environment. This robust AE/VIB sensor has a frequency range of 5 Hz-2 kHz for the vibration component and a range of 200-400 kHz for the acoustic emission component. The sensor weight is comparable to accelerometers currently used in flying aircraft. Traditional signal processing approaches are not effective due to high signal attenuation and strong background noise conditions, commonly found in aircraft drive train systems. As an alternative, we will introduce a new Supervised Pattern Recognition (SPR) methodology that allows for simultaneous processing of the signals detected by the AE/VIB sensor and their classification in near-real time, even in these adverse conditions. Finally, we

  17. Miniaturized Mid-Infrared Sensor Technologies

    SciTech Connect

    Kim, S; Young, C; Mizaikoff, B

    2007-08-16

    Fundamental vibrational and rotational modes associated with most inorganic and organic molecules are spectroscopically accessible within the mid-infrared (MIR; 3-20 {micro}m) regime of the electromagnetic spectrum. The interaction between MIR photons and organic molecules provides particularly sharp transitions, which - despite the wide variety of organic molecules - provide unique MIR absorption spectra reflecting the molecularly characteristic arrangement of chemical bonds within the probed molecules via the frequency position of the associated vibrational and rotational transitions. Given the inherent molecular selectivity and achievable sensitivity, MIR spectroscopy provides an ideal platform for optical sensing applications. Despite this potential, early MIR sensing applications were limited to localized applications due to the size of the involved instrumentation, and limited availability of appropriately compact MIR optical components including light sources, detectors, waveguides, and spectrometers. During the last decades, engineering advances in photonics and optical engineering have facilitated the translation of benchtop-style MIR spectroscopy into miniaturized optical sensing schemes providing a footprint compatible with portable instrumentation requirements for field deployable analytical tools. In this trend article, we will discuss recent advances and future strategies for miniaturizing MIR sensor technology. The Beer-Lambert law implies that achievable limit of detection (LOD) for any optical sensor system improves by increasing the interaction length between photons and target analyte species such as e.g., folding the optical path multiple times as in multi-pass gas phase sensing; however, this governing paradigm naturally leads to an increase in system dimensions. Hence, miniaturization of optical sensing system requires scaling down of each optical component, yet improving the performance of each optical element within a smaller form factor for

  18. Primate drum kit: a system for studying acoustic pattern production by non-human primates using acceleration and strain sensors.

    PubMed

    Ravignani, Andrea; Matellán Olivera, Vicente; Gingras, Bruno; Hofer, Riccardo; Rodríguez Hernández, Carlos; Sonnweber, Ruth-Sophie; Fitch, W Tecumseh

    2013-01-01

    The possibility of achieving experimentally controlled, non-vocal acoustic production in non-human primates is a key step to enable the testing of a number of hypotheses on primate behavior and cognition. However, no device or solution is currently available, with the use of sensors in non-human animals being almost exclusively devoted to applications in food industry and animal surveillance. Specifically, no device exists which simultaneously allows: (i) spontaneous production of sound or music by non-human animals via object manipulation, (ii) systematical recording of data sensed from these movements, (iii) the possibility to alter the acoustic feedback properties of the object using remote control. We present two prototypes we developed for application with chimpanzees (Pan troglodytes) which, while fulfilling the aforementioned requirements, allow to arbitrarily associate sounds to physical object movements. The prototypes differ in sensing technology, costs, intended use and construction requirements. One prototype uses four piezoelectric elements embedded between layers of Plexiglas and foam. Strain data is sent to a computer running Python through an Arduino board. A second prototype consists in a modified Wii Remote contained in a gum toy. Acceleration data is sent via Bluetooth to a computer running Max/MSP. We successfully pilot tested the first device with a group of chimpanzees. We foresee using these devices for a range of cognitive experiments. PMID:23912427

  19. Primate Drum Kit: A System for Studying Acoustic Pattern Production by Non-Human Primates Using Acceleration and Strain Sensors

    PubMed Central

    Ravignani, Andrea; Olivera, Vicente Matellán; Gingras, Bruno; Hofer, Riccardo; Hernández, Carlos Rodríguez; Sonnweber, Ruth-Sophie; Fitch, W. Tecumseh

    2013-01-01

    The possibility of achieving experimentally controlled, non-vocal acoustic production in non-human primates is a key step to enable the testing of a number of hypotheses on primate behavior and cognition. However, no device or solution is currently available, with the use of sensors in non-human animals being almost exclusively devoted to applications in food industry and animal surveillance. Specifically, no device exists which simultaneously allows: (i) spontaneous production of sound or music by non-human animals via object manipulation, (ii) systematical recording of data sensed from these movements, (iii) the possibility to alter the acoustic feedback properties of the object using remote control. We present two prototypes we developed for application with chimpanzees (Pan troglodytes) which, while fulfilling the aforementioned requirements, allow to arbitrarily associate sounds to physical object movements. The prototypes differ in sensing technology, costs, intended use and construction requirements. One prototype uses four piezoelectric elements embedded between layers of Plexiglas and foam. Strain data is sent to a computer running Python through an Arduino board. A second prototype consists in a modified Wii Remote contained in a gum toy. Acceleration data is sent via Bluetooth to a computer running Max/MSP. We successfully pilot tested the first device with a group of chimpanzees. We foresee using these devices for a range of cognitive experiments. PMID:23912427

  20. Acoustic Characteristics of Various Treatment Panel Designs for HSCT Ejector Liner Acoustic Technology Development Program

    NASA Technical Reports Server (NTRS)

    Salikuddin, M.; Kraft, R. E.; Syed, A. a.; Vu, D. D.; Mungur, P.; Langenbrunner, L. E.; Majjigi, R. K.

    2006-01-01

    The objectives of the initial effort (Phase I) of HSR Liner Technology Program, the selection of promising liner concepts, design and fabrication of these concepts for laboratory tests, testing these liners in the laboratory by using impedance tube and flow ducts, and developing empirical impedance/suppression correlation, are successfully completed. Acoustic and aerodynamic criteria for the liner design are established. Based on these criteria several liners are designed. The liner concepts designed and fabricated include Single-Degree-of-Freedom (SDOF), Two-Degree-of-Freedom (2DOF), and Bulk Absorber. Two types of SDOF treatment are fabricated, one with a perforated type face plate and the other with a wiremesh (woven) type faceplate. In addition, special configurations of these concepts are also included in the design. Several treatment panels are designed for parametric study. In these panels the facesheets of different porosity, hole diameter, and sheet thickness are utilized. Several deep panels (i.e., 1 in. deep) are designed and instrumented to measure DC flow resistance and insitu impedance in the presence of grazing flow. Basic components of these panels (i.e., facesheets, bulk materials, etc.) are also procured and tested. The results include DC flow resistance, normal impedance, and insertion loss.

  1. Sensor Data Management, Validation, Correction, and Provenance for Building Technologies

    SciTech Connect

    Castello, Charles C; Sanyal, Jibonananda; Rossiter, Jeffrey S; Hensley, Zachary; New, Joshua Ryan

    2014-01-01

    Oak Ridge National Laboratory (ORNL) conducts research on technologies that use a wide range of sensors to develop and characterize building energy performance. The management of high-resolution sensor data, analysis, and tracing lineage of such activities is challenging. Missing or corrupt data due to sensor failure, fouling, drifting, calibration error, or data logger failure is another issue. This paper focuses on sensor data management, validation, correction, and provenance to combat these issues, ensuring complete and accurate sensor datasets for building technologies applications and research. The design and development of two integrated software products are discussed: Sensor Data Validation and Correction (SensorDVC) and the Provenance Data Management System (ProvDMS) platform.

  2. CMOS Imaging Sensor Technology for Aerial Mapping Cameras

    NASA Astrophysics Data System (ADS)

    Neumann, Klaus; Welzenbach, Martin; Timm, Martin

    2016-06-01

    In June 2015 Leica Geosystems launched the first large format aerial mapping camera using CMOS sensor technology, the Leica DMC III. This paper describes the motivation to change from CCD sensor technology to CMOS for the development of this new aerial mapping camera. In 2002 the DMC first generation was developed by Z/I Imaging. It was the first large format digital frame sensor designed for mapping applications. In 2009 Z/I Imaging designed the DMC II which was the first digital aerial mapping camera using a single ultra large CCD sensor to avoid stitching of smaller CCDs. The DMC III is now the third generation of large format frame sensor developed by Z/I Imaging and Leica Geosystems for the DMC camera family. It is an evolution of the DMC II using the same system design with one large monolithic PAN sensor and four multi spectral camera heads for R,G, B and NIR. For the first time a 391 Megapixel large CMOS sensor had been used as PAN chromatic sensor, which is an industry record. Along with CMOS technology goes a range of technical benefits. The dynamic range of the CMOS sensor is approx. twice the range of a comparable CCD sensor and the signal to noise ratio is significantly better than with CCDs. Finally results from the first DMC III customer installations and test flights will be presented and compared with other CCD based aerial sensors.

  3. A wireless demodulation system for passive surface acoustic wave torque sensor.

    PubMed

    Ji, Xiaojun; Fan, Yanping; Qi, Hongli; Chen, Jing; Han, Tao; Cai, Ping

    2014-12-01

    Surface acoustic wave (SAW) resonators are utilized as torque sensors for their passive and wireless features. However, the response of a SAW torque sensor is difficult to detect because of the transient response duration and interruption of channel noise, which limit the application of SAW torque sensors. The sensitive mechanism and response function of a passive wireless SAW torque sensor are analyzed in this study. A novel demodulation system involving both hardware and software is developed for the SAW torque sensor. A clipping amplifier is utilized in the hardware to widen the dynamic response range and increase the length of the valid signal. Correlation extension and centroid algorithms are designed to lengthen the received signal and improve the estimation accuracy of the center frequency of the response signal, respectively. Meanwhile, a fast binary search algorithm is proposed to accelerate the scanning cycle according to the developed response function. Finally, the SAW torque sensor demodulation system is set up and SAW resonators with high sensitivity are fabricated on a quartz substrate. The presented demodulation system is tested, and a standard deviation of 0.28 kHz is achieved. This value is much smaller than that of classic and modern spectrum estimation methods. The sensitivity of resonance frequency shift versus torque on the shaft of the assembled senor is 2.03 kHz/Nm; the coefficient of determination is 0.999, and the linearity is 0.87%. Experimental results verify the validity and feasibility of the proposed SAW torque sensor demodulation system. PMID:25554317

  4. A new sparse design method on phased array-based acoustic emission sensor for partial discharge detection

    NASA Astrophysics Data System (ADS)

    Xie, Qing; Cheng, Shuyi; Lü, Fangcheng; Li, Yanqing

    2014-03-01

    The acoustic detecting performance of a partial discharge (PD) ultrasonic sensor array can be improved by increasing the number of array elements. However, it will increase the complexity and cost of the PD detection system. Therefore, a sparse sensor with an optimization design can be chosen to ensure good acoustic performance. In this paper, first, a quantitative method is proposed for evaluating the acoustic performance of a square PD ultrasonic array sensor. Second, a method of sparse design is presented to combine the evaluation method with the chaotic monkey algorithm. Third, an optimal sparse structure of a 3 × 3 square PD ultrasonic array sensor is deduced. It is found that, under different sparseness and sparse structure, the main beam width of the directivity function shows a small variation, while the sidelobe amplitude shows a bigger variation. For a specific sparseness, the acoustic performance under the optimal sparse structure is close to that using a full array. Finally, some simulations based on the above method show that, for certain sparseness, the sensor with the optimal sparse structure exhibits superior positioning accuracy compared to that with a stochastic one. The sensor array structure may be chosen according to the actual requirements for an actual engineering application.

  5. Optical Fiber Sensor Technologies for Efficient and Economical Oil Recovery

    SciTech Connect

    Wang, a.; Pickrell, G.; Xiao, H.; May, r.

    2003-02-27

    The overall goal of this project was to develop reliable cost effective sensors for application in the down-hole environment. The physical parameters measured by these sensors were temperature, pressure, flow and acoustic signals. Sensor head configurations for each of the physical measurands were optimized to increase the sensitivity to the particular measurand of interest while decreasing the cross-sensitivity to the other physical measurands and to environmental influences. In addition, the optical signal demodulation electronics was designed to be insensitive to environmental influences while maintaining the required resolution, precision and accuracy of the parameter being sensed. The influence of potentially detrimental agents such as water in the down-hole environment was investigated as well as methods to protect both the optical fiber and the sensor from these detrimental effects.

  6. Evaluation of an acoustic resonance temperature sensor for transformers: Final report

    SciTech Connect

    Benke, F.; Dell, T.; Gannon, G.; Geil, F.; Nomm, M.; Thompson, J.; Wright, L.; Yannucci, D.

    1987-08-01

    This report covers the development of a system for measuring power transformer hottest spot at high voltage under load. An acoustic sensor previously used in oceanic research was miniaturized and placed in contact with the coil. An insulating waveguide system was developed for voltage isolation; and the electronic system designed and built for readout and relay operation. The system was successfully demonstrated on one commercial order at high overloads. As much as 15/sup 0/ difference was shown between the presently available simulated device and the new system which measured actual hottest spot. Manufacturing cost of the sensor due to a high fallout rate as a result of sealing and waveguide attachment problems, and damage sustained after installation on the heavy coils during subsequent coil manufacture handling, preclude the use of this system at this time. 60 figs.

  7. A PARALIND Decomposition-Based Coherent Two-Dimensional Direction of Arrival Estimation Algorithm for Acoustic Vector-Sensor Arrays

    PubMed Central

    Zhang, Xiaofei; Zhou, Min; Li, Jianfeng

    2013-01-01

    In this paper, we combine the acoustic vector-sensor array parameter estimation problem with the parallel profiles with linear dependencies (PARALIND) model, which was originally applied to biology and chemistry. Exploiting the PARALIND decomposition approach, we propose a blind coherent two-dimensional direction of arrival (2D-DOA) estimation algorithm for arbitrarily spaced acoustic vector-sensor arrays subject to unknown locations. The proposed algorithm works well to achieve automatically paired azimuth and elevation angles for coherent and incoherent angle estimation of acoustic vector-sensor arrays, as well as the paired correlated matrix of the sources. Our algorithm, in contrast with conventional coherent angle estimation algorithms such as the forward backward spatial smoothing (FBSS) estimation of signal parameters via rotational invariance technique (ESPRIT) algorithm, not only has much better angle estimation performance, even for closely-spaced sources, but is also available for arbitrary arrays. Simulation results verify the effectiveness of our algorithm. PMID:23604030

  8. Acoustics

    NASA Astrophysics Data System (ADS)

    The acoustics research activities of the DLR fluid-mechanics department (Forschungsbereich Stroemungsmechanik) during 1988 are surveyed and illustrated with extensive diagrams, drawings, graphs, and photographs. Particular attention is given to studies of helicopter rotor noise (high-speed impulsive noise, blade/vortex interaction noise, and main/tail-rotor interaction noise), propeller noise (temperature, angle-of-attack, and nonuniform-flow effects), noise certification, and industrial acoustics (road-vehicle flow noise and airport noise-control installations).

  9. REVIEW ARTICLE: Sensor communication technology towards ambient intelligence

    NASA Astrophysics Data System (ADS)

    Delsing, J.; Lindgren, P.

    2005-04-01

    This paper is a review of the fascinating development of sensors and the communication of sensor data. A brief historical introduction is given, followed by a discussion on architectures for sensor networks. Further, realistic specifications on sensor devices suitable for ambient intelligence and ubiquitous computing are given. Based on these specifications, the status and current frontline development are discussed. In total, it is shown that future technology for ambient intelligence based on sensor and actuator devices using standardized Internet communication is within the range of possibilities within five years.

  10. Intensity demodulation-based acoustic sensor using dual fiber Bragg gratings and a titanium film

    NASA Astrophysics Data System (ADS)

    Wang, Shun; Lu, Ping; Zhang, Liang; Liu, Deming; Zhang, Jiangshan

    2014-07-01

    We report on recent experimental results obtained with fiber Bragg grating (FBG) microphone for acoustic measurement. The sensing element is formed by longitudinally sticking ends of two FBGs onto a titanium film, and then being packaged in an aluminum cylinder. Due to wavelength shift of the FBGs induced by the external acoustic disturbance, the corresponding periodic fluctuation in power can be observed on the optical oscilloscope. Theoretical analysis verifies that the optical power variation, result of the titanium film vibration caused by the acoustic disturbance, possesses a linear relationship with the sound pressure in a specific range. A relatively flat frequency response in the range from 100 Hz to 1 kHz with the average signal-to-noise ratio (SNR) above 22 dB is experimentally demonstrated. The maximum sound pressure sensitivity of the proposed sensor is found to be 90 μW/Pa within a sound pressure range 100.3-118.5 dB. The sensing system presents good stability and reliability, and has the advantage of direct self-demodulation.

  11. Surface acoustic wave sensor array system for trace organic vapor detection using pattern recognition analysis

    NASA Astrophysics Data System (ADS)

    Rose-Pehrsson, Susan L.; Grate, Jay W.; Klusty, Mark

    1993-03-01

    A sensor system using surface acoustic wave (SAW) vapor sensors has been fabricated and tested against hazardous organic vapors, simulants of these vapors, and potential background vapors. The vapor tests included two- and three-component mixtures, and covered a wide relative humidity range. The sensor system was compared of four SAW devices coated with different sorbent materials with different vapor selectivities. Preconcentrators were included to improve sensitivity. The vapor experiments were organized into a large data set analyzed using pattern recognition techniques. Pattern recognition algorithms were developed to identify two different classes of hazards. The algorithms were verified against a second data set not included in the training. Excellent sensitivity was achieved by the sensor coatings, and the pattern recognition analysis, and was also examined by the preconcentrators. The system can detect hazardous vapors of interest in the ppb range even in varying relative humidity and in the presence of background vapors. The system does not false alarm to a variety of other vapors including gasoline, jet fuel, diesel fuel and cigarette smoke.

  12. A novel technique for acoustic emission monitoring in civil structures with global fiber optic sensors

    NASA Astrophysics Data System (ADS)

    Verstrynge, E.; Pfeiffer, H.; Wevers, M.

    2014-06-01

    The application of acoustic emission (AE)-based damage detection is gaining interest in the field of civil structural health monitoring. Damage progress can be detected and located in real time and the recorded AEs hold information on the fracture process which produced them. One of the drawbacks for on-site application in large-scale concrete and masonry structures is the relatively high attenuation of the ultrasonic signal, which limits the detection range of the AE sensors. Consequently, a large number of point sensors are required to cover a certain area. To tackle this issue, a global damage detection system, based on AE detection with a polarization-modulated, single mode fiber optic sensor (FOS), has been developed. The sensing principle, data acquisition and analysis in time and frequency domain are presented. During experimental investigations, this AE-FOS is applied for the first time as a global sensor for the detection of crack-induced AEs in a full-scale concrete beam. Damage progress is monitored during a cyclic four-point bending test and the AE activity, detected with the FOS, is related to the subsequent stages of damage progress in the concrete element. The results obtained with the AE-FOS are successfully linked to the mechanical behavior of the concrete beam and a qualitative correspondence is found with AE data obtained by a commercial system.

  13. An innovative acoustic sensor for first in-pile fission gas release determination - REMORA 3 experiment

    SciTech Connect

    Rosenkrantz, E.; Ferrandis, J. Y.; Augereau, F.; Lambert, T.; Fourmentel, D.; Tiratay, X.

    2011-07-01

    A fuel rod has been instrumented with a new design of an acoustic resonator used to measure in a non destructive way the internal rod plenum gas mixture composition. This ultrasonic sensor has demonstrated its ability to operate in pile during REMORA 3 irradiation experiment carried out in the OSIRIS Material Testing Reactor (CEA Saclay, France). Due to very severe experimental conditions such as temperature rising up to 150 deg.C and especially, high thermal fluence level up to 3.5 10{sup 19} n.cm{sup 2}, the initial sensor gas speed of sound efficiency measurement was strongly reduced due to the irradiation effects on the piezo-ceramic properties. Nevertheless, by adding a differential signal processing method to the initial data analysis procedure validated before irradiation, the gas resonance peaks were successfully extracted from the output signal. From these data, the molar fractions variations of helium and fission gas were measured from an adapted Virial state equation. Thus, with this sensor, the kinetics of gas release inside fuel rods could be deduced from the in-pile measurements and specific calculations. These data will also give information about nuclear reaction effect on piezo-ceramics sensor under high neutron and gamma flux. (authors)

  14. Modified particle filtering algorithm for single acoustic vector sensor DOA tracking.

    PubMed

    Li, Xinbo; Sun, Haixin; Jiang, Liangxu; Shi, Yaowu; Wu, Yue

    2015-01-01

    The conventional direction of arrival (DOA) estimation algorithm with static sources assumption usually estimates the source angles of two adjacent moments independently and the correlation of the moments is not considered. In this article, we focus on the DOA estimation of moving sources and a modified particle filtering (MPF) algorithm is proposed with state space model of single acoustic vector sensor. Although the particle filtering (PF) algorithm has been introduced for acoustic vector sensor applications, it is not suitable for the case that one dimension angle of source is estimated with large deviation, the two dimension angles (pitch angle and azimuth angle) cannot be simultaneously employed to update the state through resampling processing of PF algorithm. To solve the problems mentioned above, the MPF algorithm is proposed in which the state estimation of previous moment is introduced to the particle sampling of present moment to improve the importance function. Moreover, the independent relationship of pitch angle and azimuth angle is considered and the two dimension angles are sampled and evaluated, respectively. Then, the MUSIC spectrum function is used as the "likehood" function of the MPF algorithm, and the modified PF-MUSIC (MPF-MUSIC) algorithm is proposed to improve the root mean square error (RMSE) and the probability of convergence. The theoretical analysis and the simulation results validate the effectiveness and feasibility of the two proposed algorithms. PMID:26501280

  15. Modified Particle Filtering Algorithm for Single Acoustic Vector Sensor DOA Tracking

    PubMed Central

    Li, Xinbo; Sun, Haixin; Jiang, Liangxu; Shi, Yaowu; Wu, Yue

    2015-01-01

    The conventional direction of arrival (DOA) estimation algorithm with static sources assumption usually estimates the source angles of two adjacent moments independently and the correlation of the moments is not considered. In this article, we focus on the DOA estimation of moving sources and a modified particle filtering (MPF) algorithm is proposed with state space model of single acoustic vector sensor. Although the particle filtering (PF) algorithm has been introduced for acoustic vector sensor applications, it is not suitable for the case that one dimension angle of source is estimated with large deviation, the two dimension angles (pitch angle and azimuth angle) cannot be simultaneously employed to update the state through resampling processing of PF algorithm. To solve the problems mentioned above, the MPF algorithm is proposed in which the state estimation of previous moment is introduced to the particle sampling of present moment to improve the importance function. Moreover, the independent relationship of pitch angle and azimuth angle is considered and the two dimension angles are sampled and evaluated, respectively. Then, the MUSIC spectrum function is used as the “likehood” function of the MPF algorithm, and the modified PF-MUSIC (MPF-MUSIC) algorithm is proposed to improve the root mean square error (RMSE) and the probability of convergence. The theoretical analysis and the simulation results validate the effectiveness and feasibility of the two proposed algorithms. PMID:26501280

  16. OPTICAL FIBER SENSOR TECHNOLOGIES FOR EFFICIENT AND ECONOMICAL OIL RECOVERY

    SciTech Connect

    Kristie Cooper; Gary Pickrell; Anbo Wang

    2003-04-01

    This report summarizes technical progress over the fourth year of the ''Optical Fiber Sensor Technologies for Efficient and Economical Oil Recovery'' program, funded by the Federal Energy Technology Center of the U.S. Department of Energy, and performed by the Center for Photonics Technology of the Bradley Department of Electrical and Computer Engineering at Virginia Tech. During the reporting period, research efforts under the program were focused on the development and evaluation of the fiber optic flow sensor system, and field testing in Tulsa, OK and the second field test of the pressure and temperature sensors in Coalinga, CA. The feasibility of a self-compensating fiber optic flow sensor based on a cantilever beam and interferometer for real-time flow rate measurements in the fluid filled pipes of oil field was clearly demonstrated. In addition, field testing of the pressure and temperature sensors deployed downhole continued. These accomplishments are summarized here: (1) Theoretical analysis and simulations were performed to ensure performance of the design. (2) The sensor fabrication and packaging techniques were investigated and improved. (3) Prototype flow sensors were fabricated based on the fabrication experience of hundreds of test sensors. (4) A lab-scale flow testing system was constructed and used for sensor evaluation. (5) Field-testing was performed in both the indoor and outdoor flow testing facility at the University of Tulsa, OK. (6) Testing of a multimode white light pressure and temperature sensor system continued at the oil site of Chevron/Texaco Company (Coalinga CA).

  17. 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

  18. Acoustic Source Localization in Aircraft Interiors Using Microphone Array Technologies

    NASA Technical Reports Server (NTRS)

    Sklanka, Bernard J.; Tuss, Joel R.; Buehrle, Ralph D.; Klos, Jacob; Williams, Earl G.; Valdivia, Nicolas

    2006-01-01

    Using three microphone array configurations at two aircraft body stations on a Boeing 777-300ER flight test, the acoustic radiation characteristics of the sidewall and outboard floor system are investigated by experimental measurement. Analysis of the experimental data is performed using sound intensity calculations for closely spaced microphones, PATCH Inverse Boundary Element Nearfield Acoustic Holography, and Spherical Nearfield Acoustic Holography. Each method is compared assessing strengths and weaknesses, evaluating source identification capability for both broadband and narrowband sources, evaluating sources during transient and steady-state conditions, and quantifying field reconstruction continuity using multiple array positions.

  19. Digital seismo-acoustic signal processing aboard a wireless sensor platform

    NASA Astrophysics Data System (ADS)

    Marcillo, O.; Johnson, J. B.; Lorincz, K.; Werner-Allen, G.; Welsh, M.

    2006-12-01

    We are developing a low power, low-cost wireless sensor array to conduct real-time signal processing of earthquakes at active volcanoes. The sensor array, which integrates data from both seismic and acoustic sensors, is based on Moteiv TMote Sky wireless sensor nodes (www.moteiv.com). The nodes feature a Texas Instruments MSP430 microcontroller, 48 Kbytes of program memory, 10 Kbytes of static RAM, 1 Mbyte of external flash memory, and a 2.4-GHz Chipcon CC2420 IEEE 802.15.4 radio. The TMote Sky is programmed in TinyOS. Basic signal processing occurs on an array of three peripheral sensor nodes. These nodes are tied into a dedicated GPS receiver node, which is focused on time synchronization, and a central communications node, which handles data integration and additional processing. The sensor nodes incorporate dual 12-bit digitizers sampling a seismic sensor and a pressure transducer at 100 samples per second. The wireless capabilities of the system allow flexible array geometry, with a maximum aperture of 200m. We have already developed the digital signal processing routines on board the Moteiv Tmote sensor nodes. The developed routines accomplish Real-time Seismic-Amplitude Measurement (RSAM), Seismic Spectral- Amplitude Measurement (SSAM), and a user-configured Short Term Averaging / Long Term Averaging (STA LTA ratio), which is used to calculate first arrivals. The processed data from individual nodes are transmitted back to a central node, where additional processing may be performed. Such processing will include back azimuth determination and other wave field analyses. Future on-board signal processing will focus on event characterization utilizing pattern recognition and spectral characterization. The processed data is intended as low bandwidth information which can be transmitted periodically and at low cost through satellite telemetry to a web server. The processing is limited by the computational capabilities (RAM, ROM) of the nodes. Nevertheless, we

  20. CMOS Active Pixel Sensor Technology and Reliability Characterization Methodology

    NASA Technical Reports Server (NTRS)

    Chen, Yuan; Guertin, Steven M.; Pain, Bedabrata; Kayaii, Sammy

    2006-01-01

    This paper describes the technology, design features and reliability characterization methodology of a CMOS Active Pixel Sensor. Both overall chip reliability and pixel reliability are projected for the imagers.

  1. Acoustics

    NASA Technical Reports Server (NTRS)

    Goodman, Jerry R.; Grosveld, Ferdinand

    2007-01-01

    The acoustics environment in space operations is important to maintain at manageable levels so that the crewperson can remain safe, functional, effective, and reasonably comfortable. High acoustic levels can produce temporary or permanent hearing loss, or cause other physiological symptoms such as auditory pain, headaches, discomfort, strain in the vocal cords, or fatigue. Noise is defined as undesirable sound. Excessive noise may result in psychological effects such as irritability, inability to concentrate, decrease in productivity, annoyance, errors in judgment, and distraction. A noisy environment can also result in the inability to sleep, or sleep well. Elevated noise levels can affect the ability to communicate, understand what is being said, hear what is going on in the environment, degrade crew performance and operations, and create habitability concerns. Superfluous noise emissions can also create the inability to hear alarms or other important auditory cues such as an equipment malfunctioning. Recent space flight experience, evaluations of the requirements in crew habitable areas, and lessons learned (Goodman 2003; Allen and Goodman 2003; Pilkinton 2003; Grosveld et al. 2003) show the importance of maintaining an acceptable acoustics environment. This is best accomplished by having a high-quality set of limits/requirements early in the program, the "designing in" of acoustics in the development of hardware and systems, and by monitoring, testing and verifying the levels to ensure that they are acceptable.

  2. Secure cooperation of autonomous mobile sensors using an underwater acoustic network.

    PubMed

    Caiti, Andrea; Calabrò, Vincenzo; Dini, Gianluca; Lo Duca, Angelica; Munafò, Andrea

    2012-01-01

    Methodologies and algorithms are presented for the secure cooperation of a team of autonomous mobile underwater sensors, connected through an acoustic communication network, within surveillance and patrolling applications. In particular, the work proposes a cooperative algorithm in which the mobile underwater sensors (installed on Autonomous Underwater Vehicles-AUVs) respond to simple local rules based on the available information to perform the mission and maintain the communication link with the network (behavioral approach). The algorithm is intrinsically robust: with loss of communication among the vehicles the coverage performance (i.e., the mission goal) is degraded but not lost. The ensuing form of graceful degradation provides also a reactive measure against Denial of Service. The cooperative algorithm relies on the fact that the available information from the other sensors, though not necessarily complete, is trustworthy. To ensure trustworthiness, a security suite has been designed, specifically oriented to the underwater scenario, and in particular with the goal of reducing the communication overhead introduced by security in terms of number and size of messages. The paper gives implementation details on the integration between the security suite and the cooperative algorithm and provides statistics on the performance of the system as collected during the UAN project sea trial held in Trondheim, Norway, in May 2011. PMID:22438748

  3. Recent developments on surface acoustic wave (SAW) sensors for harsh conditions

    NASA Astrophysics Data System (ADS)

    Schiopu, Paul; Chilibon, Irinela; Grosu, Neculai; Craciun, Alexandru

    2015-02-01

    The results of research into Surface Acoustic Waves (SAW) devices have been recognized for their efficiency and versatility in the electrical signals processing. Actual progress in the industrial application of piezoelectric materials such as Lithium Niobate (LiNbO3), Langasite (LGS), Lanthanum-Gallium Silicate La3Ga5SiO14 and Gallium Orthophosphate (GaPO4), allows the manufacturing of devices with piezoelectric performances, which overcome the limits obtained with quartz crystals. The single crystal materials have a long term high stability - near to infinite - and moreover, some of these have an excellent behavior with temperature variation. Today, GaPO4 with its properties is by far the best suited piezoelectric material to be used in sensor applications for machine monitoring and pressure measurements, at high temperatures. SAW micro devices based on GaPO4 operate at temperatures of up to 8000C. For a particular case, of harsh-environment applications, additional challenges need to be overcome, relating to substrate integrity and operation, thin film electrode fabrication, device packaging, and sensor interrogation. This paper reviews the novel progres in the area of (SAW) sensors for harsh conditions.

  4. Acoustic sensor planning for gunshot location in national parks: a pareto front approach.

    PubMed

    González-Castaño, Francisco Javier; Alonso, Javier Vales; Costa-Montenegro, Enrique; López-Matencio, Pablo; Vicente-Carrasco, Francisco; Parrado-García, Francisco J; Gil-Castiñeira, Felipe; Costas-Rodríguez, Sergio

    2009-01-01

    In this paper, we propose a solution for gunshot location in national parks. In Spain there are agencies such as SEPRONA that fight against poaching with considerable success. The DiANa project, which is endorsed by Cabaneros National Park and the SEPRONA service, proposes a system to automatically detect and locate gunshots. This work presents its technical aspects related to network design and planning. The system consists of a network of acoustic sensors that locate gunshots by hyperbolic multi-lateration estimation. The differences in sound time arrivals allow the computation of a low error estimator of gunshot location. The accuracy of this method depends on tight sensor clock synchronization, which an ad-hoc time synchronization protocol provides. On the other hand, since the areas under surveillance are wide, and electric power is scarce, it is necessary to maximize detection coverage and minimize system cost at the same time. Therefore, sensor network planning has two targets, i.e., coverage and cost. We model planning as an unconstrained problem with two objective functions. We determine a set of candidate solutions of interest by combining a derivative-free descent method we have recently proposed with a Pareto front approach. The results are clearly superior to random seeding in a realistic simulation scenario. PMID:22303135

  5. Acoustic Sensor Planning for Gunshot Location in National Parks: A Pareto Front Approach

    PubMed Central

    González-Castaño, Francisco Javier; Alonso, Javier Vales; Costa-Montenegro, Enrique; López-Matencio, Pablo; Vicente-Carrasco, Francisco; Parrado-García, Francisco J.; Gil-Castiñeira, Felipe; Costas-Rodríguez, Sergio

    2009-01-01

    In this paper, we propose a solution for gunshot location in national parks. In Spain there are agencies such as SEPRONA that fight against poaching with considerable success. The DiANa project, which is endorsed by Cabaneros National Park and the SEPRONA service, proposes a system to automatically detect and locate gunshots. This work presents its technical aspects related to network design and planning. The system consists of a network of acoustic sensors that locate gunshots by hyperbolic multi-lateration estimation. The differences in sound time arrivals allow the computation of a low error estimator of gunshot location. The accuracy of this method depends on tight sensor clock synchronization, which an ad-hoc time synchronization protocol provides. On the other hand, since the areas under surveillance are wide, and electric power is scarce, it is necessary to maximize detection coverage and minimize system cost at the same time. Therefore, sensor network planning has two targets, i.e., coverage and cost. We model planning as an unconstrained problem with two objective functions. We determine a set of candidate solutions of interest by combining a derivative-free descent method we have recently proposed with a Pareto front approach. The results are clearly superior to random seeding in a realistic simulation scenario. PMID:22303135

  6. High frequency stability oscillator for surface acoustic wave-based gas sensor

    NASA Astrophysics Data System (ADS)

    Wang, Wen; He, Shitang; Li, Shunzhou; Pan, Yong

    2006-12-01

    This paper presents a 158 MHz surface acoustic wave (SAW) oscillator used for a gas sensor. As the oscillator element, a SAW delay line on ST-X quartz substrate with low insertion loss (<8 dB) and single mode selection capability was developed. Low insertion loss was achieved by an electrode width control single phase unidirectional transducer (EWC/SPUDT) configuration. Single mode selection was simply accomplished by a comb transducer which is a means of combining the frequency selectivity of two interdigital transducers (IDTs). Coupling of modes (COM) simulation was performed to predict device performance prior to fabrication. The measured frequency response S12 showed a good agreement with simulated results. The effect of the oscillator circuit system temperature shift upon frequency stability was observed in detail. The experimental results showed that the baseline noise was typically up to ~0.7 × 10-7 in a laboratory environment with temperature control. The oscillator was successfully applied to a gas sensor coated self-assembled composite monolayer as a sensor material for dimethyl-methyl-phosphonate (DMMP). The sensitivity for low DMMP concentration detection was evaluated as ~25 Hz mg-1 m-3, and the threshold detection limit was up to 0.5 mg m-3.

  7. LISST-ABS: A Low-Cost Submersible Acoustic Sediment Sensor

    NASA Astrophysics Data System (ADS)

    Slade, W. H.; Agrawal, Y. C.; Dana, D. R.; Leeuw, T.; Pottsmith, C.

    2015-12-01

    The development of low-cost optical sensors (i.e., transmissometers and optical backscattering sensors, OBS) produced the last significant advance in in-situ monitoring of suspended sediment concentration. However, it was well-known from fundamental physics of light scattering and laboratory work, that their response suffered from a severe non-uniformity to grain-size (varying as 1/diameter), susceptibility to biofouling, and limited dynamic range. Here we present the development of a new, low cost, single-point, 8 MHz acoustic backscatter sensor, LISST-ABS that improves on all these shortcomings. For example, the response is nearly flat over 30-400 micron diameters varying within ±30% of the mean (compared with roughly ±400% for OBS over the same size range), fouling is less serious, and the dynamic range spans 5 decades without change of electronic gain. A key innovation of the LISST-ABS is the use of backscatter signal from two range cells in order to measure and compensate for sediment attenuation, allowing a working concentration range exceeding 1 mg/L to 70 g/L (for 7 micron particles).

  8. Two clover-shaped piezoresistive silicon microphones for photo acoustic gas sensors

    NASA Astrophysics Data System (ADS)

    Grinde, C.; Sanginario, A.; Ohlckers, P. A.; Jensen, G. U.; Mielnik, M. M.

    2010-04-01

    Low cost CO2 gas sensors for demand-controlled ventilation can lower the energy consumption and increase comfort and hence productivity in office buildings and schools. The photo aoustic principle offers very high sensitivity and selectivity when used for gas trace analysis. Current systems are too expensive and large for in-duct mounting. Here, the design, modeling, fabrication and characterization of two micromachined silicon microphones with piezoresistive readout designed for low cost photo acoustic gas sensors are presented. The microphones have been fabricated using a foundry MPW service. One of the microphones has been fabricated using an additional etching step that allows etching through membranes with large variations in thickness. To increase sensitivity and resolution, a design based on a released membrane suspended by four beams was chosen. The microphones have been characterized for frequencies up to 1 kHz and 100 Hz, respectively. Averaged sensitivities are measured to be 30 µV/(V × Pa) and 400 µV/(V × Pa). The presented microphones offer increased sensitivities compared to similar sensors.

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

    PubMed

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

    2014-01-01

    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. PMID:24577520

  10. Enhanced Sensitivity of Surface Acoustic Wave-Based Rate Sensors Incorporating Metallic Dot Arrays

    PubMed Central

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

    2014-01-01

    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. PMID:24577520

  11. Secure Cooperation of Autonomous Mobile Sensors Using an Underwater Acoustic Network

    PubMed Central

    Caiti, Andrea; Calabrò, Vincenzo; Dini, Gianluca; Duca, Angelica Lo; Munafò, Andrea

    2012-01-01

    Methodologies and algorithms are presented for the secure cooperation of a team of autonomous mobile underwater sensors, connected through an acoustic communication network, within surveillance and patrolling applications. In particular, the work proposes a cooperative algorithm in which the mobile underwater sensors (installed on Autonomous Underwater Vehicles—AUVs) respond to simple local rules based on the available information to perform the mission and maintain the communication link with the network (behavioral approach). The algorithm is intrinsically robust: with loss of communication among the vehicles the coverage performance (i.e., the mission goal) is degraded but not lost. The ensuing form of graceful degradation provides also a reactive measure against Denial of Service. The cooperative algorithm relies on the fact that the available information from the other sensors, though not necessarily complete, is trustworthy. To ensure trustworthiness, a security suite has been designed, specifically oriented to the underwater scenario, and in particular with the goal of reducing the communication overhead introduced by security in terms of number and size of messages. The paper gives implementation details on the integration between the security suite and the cooperative algorithm and provides statistics on the performance of the system as collected during the UAN project sea trial held in Trondheim, Norway, in May 2011. PMID:22438748

  12. Acoustic Energy: An Innovative Technology for Stimulating Oil Wells

    SciTech Connect

    Edgar, Dorland E.; Peters, Robert W.; Johnson, Donald O.; Paulsen, P. David; Roberts, Wayne

    2006-04-30

    application of acoustic energy (sonication) significantly reduced the viscosity of crude oils, and the amount of viscosity reduction resulting is greater for more viscous, heavy crude oils than it is for less viscous, light crude oils. (2) Test results showed that after being heated, resulting viscosity reductions were not sustained following treatment to the extent that post-sonication reductions were sustained. (3) The maximum viscosity reductions in Oils 1, 2, and 3 due to sonication were 43%, 76%, and 6%, respectively. Samples of Oil 2 associated with larger viscosity reductions often exhibited a definite water separation layer follow the tests, whereas reductions of approximately 23% were measured when this separation was not observed. (4) It was observed that neither horn design nor the reduction of input power by 25% had very little effect on the ability of sonication to alter crude oil viscosity. (5) The chemical additives produced a range of viscosity reduction from 37% to a maximum of 94% with the largest reductions being facilitated by the abundant water present Oil 2. If the Oil 2 results are not considered, the maximum reduction was 73%. The effects of the additives and sonication are enhanced by each other. (6) In only one test did the viscosity return to as much as 50% of the pre-treatment value during a period of 30 days following treatment; recovery was much less in all other cases. Therefore, more than half of the viscosity reduction was maintained for a month without additional treatment. (7) Possible applications, market potential, and economic value of the implementation of a mature sonication technology within the petroleum industry were identified, and it was estimated that the potential exists that more than a billion barrels of oil could be upgraded or produced annually as a result. The project results successfully demonstrated that sonication alone and in combination with chemical additives can effectively reduce the viscosity of crude oils having a

  13. Advanced technology for space communications, tracking, and robotic sensors

    NASA Technical Reports Server (NTRS)

    Krishen, Kumar

    1989-01-01

    Technological advancements in tracking, communications, and robotic vision sensors are reviewed. The development of communications systems for multiple access, broadband, high data rate, and efficient operation is discussed. Consideration is given to the Tracking and Data Relay Satellite systems, GPS, and communications and tracking systems for the Space Shuttle and the Space Station. The use of television, laser, and microwave sensors for robotics and technology for autonomous rendezvous and docking operations are examined.

  14. Optical Sensor Technology Development and Deployment

    SciTech Connect

    B. G. Parker

    2005-01-24

    The objectives of this ESP (Enhanced Surveillance) project are to evaluate sensor performance for future aging studies of materials, components and weapon systems. The goal of this project is to provide analysis capability to experimentally identify and characterize the aging mechanisms and kinetics of Core Stack Assembly (CSA) materials. The work on fiber optic light sources, hermetic sealing of fiber optics, fiber optic hydrogen sensors, and detection systems will be discussed.

  15. Compatibility of gas and flow sensor technology fabrication

    NASA Astrophysics Data System (ADS)

    Sabate, Neus; Gracia, Isabel; Cane, Carles; Puigcorbe, Jordi; Cerda, Judith; Morante, Joan Ramon; Berganzo, Javier

    2003-04-01

    The requirements of flow measurement and control in the home-appliances field lead to the need of a measurement system able to monitor the flow and the quality of gas. The integration of a set of sensors with different functionalities on a single chip arises as an advantageous solution. In this paper, the description of the structures and technologies required for the gas, flow and temperature sensor devices is presented prior to the complete description of the process flow for the full on-chip compatibilization. In this sense, semiconductor gas sensors and thermal flow sensors have arisen as the best candidates to address the compatibilization.

  16. Passive IR polarization sensors: a new technology for mine detection

    NASA Astrophysics Data System (ADS)

    Barbour, Blair A.; Jones, Michael W.; Barnes, Howard B.; Lewis, Charles P.

    1998-09-01

    The problem of mine and minefield detection continues to provide a significant challenge to sensor systems. Although the various sensor technologies (infrared, ground penetrating radar, etc.) may excel in certain situations there does not exist a single sensor technology that can adequately detect mines in all conditions such as time of day, weather, buried or surface laid, etc. A truly robust mine detection system will likely require the fusion of data from multiple sensor technologies. The performance of these systems, however, will ultimately depend on the performance of the individual sensors. Infrared (IR) polarimetry is a new and innovative sensor technology that adds substantial capabilities to the detection of mines. IR polarimetry improves on basic IR imaging by providing improved spatial resolution of the target, an inherent ability to suppress clutter, and the capability for zero (Delta) T imaging. Nichols Research Corporation (Nichols) is currently evaluating the effectiveness of IR polarization for mine detection. This study is partially funded by the U.S. Army Night Vision & Electronic Sensors Directorate (NVESD). The goal of the study is to demonstrate, through phenomenology studies and limited field trials, that IR polarizaton outperforms conventional IR imaging in the mine detection arena.

  17. A Network Coding Based Hybrid ARQ Protocol for Underwater Acoustic Sensor Networks.

    PubMed

    Wang, Hao; Wang, Shilian; Zhang, Eryang; Zou, Jianbin

    2016-01-01

    Underwater Acoustic Sensor Networks (UASNs) have attracted increasing interest in recent years due to their extensive commercial and military applications. However, the harsh underwater channel causes many challenges for the design of reliable underwater data transport protocol. In this paper, we propose an energy efficient data transport protocol based on network coding and hybrid automatic repeat request (NCHARQ) to ensure reliability, efficiency and availability in UASNs. Moreover, an adaptive window length estimation algorithm is designed to optimize the throughput and energy consumption tradeoff. The algorithm can adaptively change the code rate and can be insensitive to the environment change. Extensive simulations and analysis show that NCHARQ significantly reduces energy consumption with short end-to-end delay. PMID:27618044

  18. Netted sensors-based vehicle acoustic classification at Tier 1 nodes

    NASA Astrophysics Data System (ADS)

    Jacyna, Garry M.; Christou, Carol T.; George, Bryan; Necioglu, Burhan F.

    2005-05-01

    The MITRE Corporation has embarked on a three-year internally-funded research program in netted sensors with applications to border monitoring, situational awareness in support of combat identification, and urban warfare. The first-year effort emphasized a border monitoring application for dismounted personnel and vehicle surveillance. This paper will focus primarily on the Tier 1 acoustic-based vehicle classification component. We discuss the development and implementation of a robust linear-weighted classifier on a Mica2 Crossbow mote using feature extraction algorithms specifically developed by MITRE for mote-based processing applications. These include a block floating point Fast Fourier Transform (FFT) algorithm and an 8-band proportional bandwidth filter bank. Results of in-field testing are compared and contrasted with theoretically-derived performance bounds.

  19. Acoustic measurement of sediment dynamics in the coastal zones using wireless sensor networks

    NASA Astrophysics Data System (ADS)

    Sudhakaran, A., II; Paramasivam, A.; Seshachalam, S.; A, C.

    2014-12-01

    Analyzing of the impact of constructive or low energy waves and deconstructive or high energy waves in the ocean are very much significant since they deform the geometry of seashore. The deformation may lead to productive result and also to the end of deteriorate damage. Constructive waves results deposition of sediment which widens the beach where as deconstructive waves results erosion which narrows the beach. Validation of historic sediment transportation and prediction of the direction of movement of seashore is essential to prevent unrecoverable damages by incorporating precautionary measurements to identify the factors that influence sediment transportation if feasible. The objective of this study is to propose a more reliable and energy efficient Information and communication system to model the Coastal Sediment Dynamics. Various factors influencing the sediment drift at a particular region is identified. Consequence of source depth and frequency dependencies of spread pattern in the presence of sediments is modeled. Property of source depth and frequency on sensitivity to values of model parameters are determined. Fundamental physical reasons for these sediment interaction effects are given. Shallow to deep water and internal and external wave model of ocean is obtained intended to get acoustic data assimilation (ADA). Signal processing algorithms are used over the observed data to form a full field acoustic propagation model and construct sound speed profile (SSP). The inversions of data due to uncertainties at various depths are compared. The impact of sediment drift over acoustic data is identified. An energy efficient multipath routing scheme Wireless sensor networks (WSN) is deployed for the well-organized communication of data. The WSN is designed considering increased life time, decreased power consumption, free of threats and attacks. The practical data obtained from the efficient system to model the ocean sediment dynamics are evaluated with remote

  20. Sound-maps of environmentally sensitive areas constructed from Wireless Acoustic Sensors Network data

    NASA Astrophysics Data System (ADS)

    Michailidis, E. T.; Liaperdos, J.; Tatlas, N.-A.; Potirakis, S. M.; Rangoussi, M.

    2016-03-01

    “E-SOUNDMAPS” is a distributed microelectronic system for the sound/acoustic monitoring of areas of environmental interest that is based on an appropriately designed wireless acoustic sensor network (WASN). It involves the automated generation of multi-level sound-maps for environmental assessment of areas of interest. This paper focuses on the method and the software application for the construction of sound-maps, which is developed as part of the integrated “E-SOUNDMAPS” system. The software application periodically produces geographically-referenced, accurate environmental sound information, based on real- field measurement data, and integrates them in the geographic map of the area of interest in a concise and comprehensive manner. Following the field recording of sound and the hierarchical recognition/classification of sound events and corresponding sources, the obtained sound sources characterization tags feed the specific software application. The output is a multilevel soundmap, constructed on the basis of the data and published electronically on the Web, for human inspection and assessment. All necessary steps for handling, archiving, monitoring, visualization and retrieval of sound data are also presented.

  1. Lightweight Filter Architecture for Energy Efficient Mobile Vehicle Localization Based on a Distributed Acoustic Sensor Network

    PubMed Central

    Kim, Keonwook

    2013-01-01

    The generic properties of an acoustic signal provide numerous benefits for localization by applying energy-based methods over a deployed wireless sensor network (WSN). However, the signal generated by a stationary target utilizes a significant amount of bandwidth and power in the system without providing further position information. For vehicle localization, this paper proposes a novel proximity velocity vector estimator (PVVE) node architecture in order to capture the energy from a moving vehicle and reject the signal from motionless automobiles around the WSN node. A cascade structure between analog envelope detector and digital exponential smoothing filter presents the velocity vector-sensitive output with low analog circuit and digital computation complexity. The optimal parameters in the exponential smoothing filter are obtained by analytical and mathematical methods for maximum variation over the vehicle speed. For stationary targets, the derived simulation based on the acoustic field parameters demonstrates that the system significantly reduces the communication requirements with low complexity and can be expected to extend the operation time considerably. PMID:23979482

  2. Design and analysis of air acoustic vector-sensor configurations for two-dimensional geometry.

    PubMed

    Wajid, Mohd; Kumar, Arun; Bahl, Rajendar

    2016-05-01

    Acoustic vector-sensors (AVS) have been designed using the P-P method for different microphone configurations. These configurations have been used to project the acoustic intensity on the orthogonal axes through which the direction of arrival (DoA) of a sound source has been estimated. The analytical expressions for the DoA for different microphone configurations have been derived for two-dimensional geometry. Finite element method simulation using COMSOL-Multiphysics has been performed, where the microphone signals for AVS configurations have been recorded in free field conditions. The performance of all the configurations has been evaluated with respect to angular error and root-mean-square angular error. The simulation results obtained with ideal geometry for different configurations have been corroborated experimentally with prototype AVS realizations and also compared with microphone-array method, viz., Multiple Signal Classification and Generalized Cross Correlation. Experiments have been performed in an anechoic room using different prototype AVS configurations made from small size microphones. The DoA performance using analytical expressions, simulation studies, and experiments with prototype AVS in anechoic chamber are presented in the paper. The square and delta configurations are found to perform better in the absence and presence of noise, respectively. PMID:27250174

  3. Lightweight filter architecture for energy efficient mobile vehicle localization based on a distributed acoustic sensor network.

    PubMed

    Kim, Keonwook

    2013-01-01

    The generic properties of an acoustic signal provide numerous benefits for localization by applying energy-based methods over a deployed wireless sensor network (WSN). However, the signal generated by a stationary target utilizes a significant amount of bandwidth and power in the system without providing further position information. For vehicle localization, this paper proposes a novel proximity velocity vector estimator (PVVE) node architecture in order to capture the energy from a moving vehicle and reject the signal from motionless automobiles around the WSN node. A cascade structure between analog envelope detector and digital exponential smoothing filter presents the velocity vector-sensitive output with low analog circuit and digital computation complexity. The optimal parameters in the exponential smoothing filter are obtained by analytical and mathematical methods for maximum variation over the vehicle speed. For stationary targets, the derived simulation based on the acoustic field parameters demonstrates that the system significantly reduces the communication requirements with low complexity and can be expected to extend the operation time considerably. PMID:23979482

  4. Low-cost hydrogen sensors: Technology maturation progress

    SciTech Connect

    Hoffheins, B.S.; Rogers, J.E.; Lauf, R.J.; Egert, C.M.; Haberman, D.P.

    1998-04-01

    The authors are developing a low-cost, solid-state hydrogen sensor to support the long-term goals of the Department of Energy (DOE) Hydrogen Program to encourage acceptance and commercialization of renewable energy-based technologies. Development of efficient production, storage, and utilization technologies brings with it the need to detect and pinpoint hydrogen leaks to protect people and equipment. The solid-state hydrogen sensor, developed at Oak Ridge National Laboratory (ORNL), is potentially well-suited to meet cost and performance objectives for many of these applications. Under a cooperative research and development Agreement and license agreement, they are teaming with a private company, DCH Technology, Inc., to develop the sensor for specific market applications related to the use of hydrogen as an energy vector. This report describes the current efforts to optimize materials and sensor performance to reach the goals of low-cost fabrication and suitability for relevant application areas.

  5. Spaceborne sensors (1983-2000 AD): A forecast of technology

    NASA Technical Reports Server (NTRS)

    Kostiuk, T.; Clark, B. P.

    1984-01-01

    A technical review and forecast of space technology as it applies to spaceborne sensors for future NASA missions is presented. A format for categorization of sensor systems covering the entire electromagnetic spectrum, including particles and fields is developed. Major generic sensor systems are related to their subsystems, components, and to basic research and development. General supporting technologies such as cryogenics, optical design, and data processing electronics are addressed where appropriate. The dependence of many classes of instruments on common components, basic R&D and support technologies is also illustrated. A forecast of important system designs and instrument and component performance parameters is provided for the 1983-2000 AD time frame. Some insight into the scientific and applications capabilities and goals of the sensor systems is also given.

  6. Advanced acoustic cavity technology. [for hydrogen oxygen rocket engines

    NASA Technical Reports Server (NTRS)

    Hines, W. S.; Oberg, C. L.; Kusak, L.

    1974-01-01

    A series of rocket motor firings was performed in a modified linear aerospike thrust chamber with the H2/O2 propellant combination to allow determination of the physical properties of the combustion gases in acoustic cavities located in the chamber side walls. A preliminary analytical study was first conducted to define theoretically both the appropriate cavity dimensions and the combustion gas flow field adjacent to the cavity openings. During the subsequent motor firings, cavity gas temperature profiles were measured and gas samples were withdrawn from the bottom of the cavities for compositional analysis by measurement of pressure/temperature variation and gas chromatography. Data were obtained with both radially and axially oriented cavities and with and without hydrogen bleed flow through the cavities. A simplified procedure was developed for predicting gas cavity and acoustic velocity for use in acoustic cavity design analyses.

  7. Piezoelectric Actuator/Sensor Technology at Rockwell

    NASA Technical Reports Server (NTRS)

    Neurgaonkar, Ratnakar R.

    1996-01-01

    We describe the state-of-the art of piezoelectric materials based on perovskite and tungsten bronze families for sensor, actuator and smart structure applications. The microstructural defects in these materials have been eliminated to a large extent and the resulting materials exhibit exceedingly high performance for various applications. The performance of Rockwell actuators/sensors is at least 3 times better than commercially available products. These high performance actuators are being incorporated into various applications including, DOD, NASA and commercial. The multilayer actuator stacks fabricated from our piezoceramics are advantageous for sensing and high capacitance applications. In this presentation, we will describe the use of our high performance piezo-ceramics for actuators and sensors, including multilayer stacks and composite structures.

  8. Portable sensor technology for rotational ground motions

    NASA Astrophysics Data System (ADS)

    Bernauer, Felix; Wassermann, Joachim; Guattari, Frédéric; Igel, Heiner

    2016-04-01

    In this contribution we present performance characteristics of a single component interferometric fiber-optic gyroscope (IFOG). The prototype sensor is provided by iXBlue, France. It is tested in the framework of the European Research Council Project, ROMY (Rotational motions - a new observable for seismology), on its applicability as a portable and field-deployable sensor for rotational ground motions. To fully explore the benefits of this new seismic observable especially in the fields of vulcanology, ocean generated noise and geophysical exploration, such a sensor has to fulfill certain requirements regarding portability, power consumption, time stamping stability and dynamic range. With GPS-synchronized time stamping and miniseed output format, data acquisition is customized for the use in seismology. Testing time stamping accuracy yields a time shift of less than 0.0001 s and a correlation coefficient of 0.99 in comparison to a commonly used data acquisition system, Reftek 120. Sensor self-noise is below 5.0 ṡ 10‑8 rads‑1Hz‑1/2 for a frequency band from 0.001 Hz to 5.0 Hz. Analysis of Allan deviation shows an angle random walk of 3.5 ṡ 10‑8 rads‑1Hz‑1/2. Additionally, the operating range diagram is shown and ambient noise analysis is performed. The sensitivity of sensor self-noise to variations in surrounding temperature and magnetic field is tested in laboratory experiments. With a power consumption of less than 10 W, the whole system (single component sensor + data acquisition) is appropriate for field use with autonomous power supply.

  9. Integrated imaging sensor systems with CMOS active pixel sensor technology

    NASA Technical Reports Server (NTRS)

    Yang, G.; Cunningham, T.; Ortiz, M.; Heynssens, J.; Sun, C.; Hancock, B.; Seshadri, S.; Wrigley, C.; McCarty, K.; Pain, B.

    2002-01-01

    This paper discusses common approaches to CMOS APS technology, as well as specific results on the five-wire programmable digital camera-on-a-chip developed at JPL. The paper also reports recent research in the design, operation, and performance of APS imagers for several imager applications.

  10. Application of fiber grating-based acoustic sensor in progressive failure testing of e-glass/vinylester curve composites

    NASA Astrophysics Data System (ADS)

    Azmi, Asrul Izam; Raju, Raju; Peng, Gang-Ding

    2012-02-01

    This paper reports an application of phase shifted fiber Bragg grating (PS-FBG) intensity-type acoustic sensor in a continuous and in-situ failure testing of an E-glass/vinylester top hat stiffener (THS). The narrow transmission channel of the PS-FBG is highly sensitive to small perturbation, hence suitable to be used in an effective acoustic emission (AE) assessment technique. The progressive failure of THS was tested under transverse loading to experimentally simulate the actual loading in practice. Our experimental tests have demonstrated, in good agreement with the commercial piezoelectric sensors, that the important failures information of the THS was successfully recorded by the simple intensity-type PS-FBG sensor.

  11. The Nature of Exhibits About Acoustics in Science and Technology Centres

    NASA Astrophysics Data System (ADS)

    Afonso, Ana S.; Gilbert, John K.

    2008-11-01

    This is a study of the opportunities currently provided by interactive science and technology centres for visitors’ engagement in the field of acoustics. E-mails, requesting a description of exhibits on acoustics (sound and hearing) in use, were sent to members of staff of interactive science and technology centres around the world as well as to companies that design and sell exhibits. Eighty-seven descriptions of distinctive interactive exhibits were received and analysed. Results show that: there are few analogy-based exhibits concerning the more complex aspects of acoustics; narratives involving visitors’ everyday lives, that might provide continuity between and beyond the situations presented by exhibits, are not generally provided; science is emphasised at the expense of technology; the risks, benefits and ethical implications of relevant technological artefacts are rarely mentioned; the majority of the exhibits are concerned with the fields of fundamental acoustics, hearing, and psychoacoustics. It is suggested that interactive science and technology centres need to rethink the design of exhibits about acoustics if their mission includes some appreciation of this important branch of science and technology.

  12. Networked sensors for the future force (NSFF) advanced technology demonstration (ATD) communications systems

    NASA Astrophysics Data System (ADS)

    Nemeroff, Jay; DiPierro, Stefano

    2005-05-01

    The U.S. Army"s Future Combat Systems (FCS) and Future Force Warrior (FFW) will rely on the use of unattended, tactical sensors to detect and identify enemy targets in order to avoid enemy fires and enable precise networked fire to survive on the future battlefield with less armor protection. Successful implementation of these critical sensor fields requires the development of a specialized communications network infrastructure needed to disseminate sensor data to provide relevant, timely and accurate situational awareness information to the tactical common operating picture. The sensor network communications must support both static deployed and mobile ground and air robotic sensor arrays with robust, secure, stealthy, and jam resistant links. It is envisioned that tactical sensor networks can be deployed in a two tiered communications architecture that includes a lower sensor sub-layer consisting of acoustic, magnetic, Chemical/Biological and seismic detectors and an upper sub-layer consisting of infrared or visual imaging cameras. The upper sub-layer can be cued by the lower sub-layer and provides a seamless gateway link to higher echelon backbone tactical networks. The NSFF Advanced Technology Demonstration (ATD) communications effort focuses on providing Future Force systems such as the FCS and the Future Force Warrior with critical situational awareness data needed for survivability. The communications systems supporting this functionality must be designed such that unattended ground sensor data can flow seamlessly from the lowest unattended tactical sensor echelons into the Army"s tactical backbone networks while also allowing the "fusing" of the data with other intelligence information for correlation within a tactical command and control node. NSFF is realizing this capability by using advanced communications technologies developed under the Soldier Level Integrated Communications Environment (SLICE) Soldier Radio Waveform (SRW) project. These technologies

  13. Humidity Sensors Principle, Mechanism, and Fabrication Technologies: A Comprehensive Review

    PubMed Central

    Farahani, Hamid; Wagiran, Rahman; Hamidon, Mohd Nizar

    2014-01-01

    Humidity measurement is one of the most significant issues in various areas of applications such as instrumentation, automated systems, agriculture, climatology and GIS. Numerous sorts of humidity sensors fabricated and developed for industrial and laboratory applications are reviewed and presented in this article. The survey frequently concentrates on the RH sensors based upon their organic and inorganic functional materials, e.g., porous ceramics (semiconductors), polymers, ceramic/polymer and electrolytes, as well as conduction mechanism and fabrication technologies. A significant aim of this review is to provide a distinct categorization pursuant to state of the art humidity sensor types, principles of work, sensing substances, transduction mechanisms, and production technologies. Furthermore, performance characteristics of the different humidity sensors such as electrical and statistical data will be detailed and gives an added value to the report. By comparison of overall prospects of the sensors it was revealed that there are still drawbacks as to efficiency of sensing elements and conduction values. The flexibility offered by thick film and thin film processes either in the preparation of materials or in the choice of shape and size of the sensor structure provides advantages over other technologies. These ceramic sensors show faster response than other types. PMID:24784036

  14. Applications of the Sensor Fish Technology

    SciTech Connect

    Deng, Zhiqun; Carlson, Thomas J.; Duncan, Joanne P.; Richmond, Marshall C.

    2007-08-28

    The Sensor Fish is an autonomous device developed at Pacific Northwest National Laboratory for U.S. Department of Energy (DOE) and Army Corps of Engineers (COE) to better understand the physical conditions fish experience during passage through hydro-turbines and other dam bypass alternatives. Since its initial development in 1997, the Sensor Fish has undergone several design changes to improve its function and extend the range of its use. The most recent Sensor Fish design, the six-degree-of-freedom (6DOF) device, has been deployed successfully to characterize the environment fish experience when they pass through several hydroelectric projects along main stem Columbia and Snake Rivers in the Pacific Northwest. Just as information gathered from crash test dummies can affect automobile design with the installation of protective designs to lessen or prevent human injury, having sensor fish data to quantify accelerations, rotations, and pressure changes, helps identify fish injury mechanisms such as strike, turbulent shear, pressure, and inertial effects, including non-lethal ones such as stunning or signs of vestibular disruption that expose fish to a higher risk of predation by birds and piscivorous fish downstream following passage.

  15. Sensor Acquisition for Water Utilities: A Survey and Technology List

    SciTech Connect

    Alai, M; Glascoe, L; Love, A; Johnson, M; Einfeld, W

    2005-03-07

    The early detection of the deliberate biological and chemical contamination of water distribution systems is a necessary capability for securing the nation's water supply. Current and emerging early-detection technology capabilities and shortcomings need to be identified and assessed to provide government agencies and water utilities with an improved methodology for assessing the value of installing these technologies. The Department of Homeland Security (DHS) has tasked a multi-laboratory team to evaluate current and future needs to protect the nation's water distribution infrastructure by supporting an objective evaluation of current and new technologies. The primary deliverables from this Operational Technology Demonstration (OTD) are the following: (1) establishment of an advisory board for review and approval of testing protocols, technology acquisition processes and recommendations for technology test and evaluation in laboratory and field settings; (2) development of a technology acquisition process; (3) creation of laboratory and field testing and evaluation capability; and (4) testing of candidate technologies for insertion into a water early warning system. The initial phase of this study involves the development of two separate but complementary strategies to be reviewed by the advisory board: (1) a technology acquisition strategy, and (2) a technology evaluation strategy. Lawrence Livermore National Laboratory and Sandia National Laboratories are tasked with the first strategy, while Los Alamos, Pacific Northwest, and Oak Ridge National Laboratories are tasked with the second strategy. The first goal of the acquisition strategy is the development of a technology survey process that includes a review of previous sensor surveys and current test programs and then the development of a method to solicit and select existing and emerging sensor technologies for evaluation and testing. In this paper we discuss a survey of previous efforts by governmental

  16. Optical pressure/acoustic sensor with precise Fabry-Perot cavity length control using angle polished fiber.

    PubMed

    Wang, Wenhui; Wu, Nan; Tian, Ye; Wang, Xingwei; Niezrecki, Christopher; Chen, Julie

    2009-09-14

    This paper presents a novel Fabry-Perot (FP) optical fiber pressure/acoustic sensor. It consists of two V-shaped grooves having different sized widths, a diaphragm on the surface of the larger V-groove, and a 45 degrees angle-polished fiber. The precision of FP cavity length is determined by the fabrication process of photolithography and anisotropic etching of a silicon crystal. Therefore, the cavity length can be controlled on the order of ten nm. Sensors were fabricated and tested. Test results indicate that the sensors' cavity lengths have been controlled precisely. The packaged sensor has demonstrated very good static and dynamic responses compared to a commercially available pressure sensor and a microphone. PMID:19770876

  17. Low-power highly miniaturized image sensor technology

    NASA Astrophysics Data System (ADS)

    Mansoorian, Karmak; Fossum, Eric R.

    1997-01-01

    A second generation image sensor technology has been developed at the NASA Jet Propulsion Laboratory with performance comparable to charge-coupled device (CCDs). This sensor is implemented using the industry-standard complementary metal-oxide semiconductor (CMOS) technology employed for nearly all microprocessors and memory chips and thus takes advantage of the rapid worldwide development of this technology. The CMOS active pixel sensor (APS) maintains the performance of CCDs regarding noise and quantum efficiency and offers unique advantages for ultra low power focal plane operation and integration of supporting electronics such as timing, control, clock, signal chains and analog-to-digital converters. This paper describes the technology for implementing a low power camera-on-a-chip.

  18. An Enhanced Energy Balanced Data Transmission Protocol for Underwater Acoustic Sensor Networks

    PubMed Central

    Javaid, Nadeem; Shah, Mehreen; Ahmad, Ashfaq; Imran, Muhammad; Khan, Majid Iqbal; Vasilakos, Athanasios V.

    2016-01-01

    This paper presents two new energy balanced routing protocols for Underwater Acoustic Sensor Networks (UASNs); Efficient and Balanced Energy consumption Technique (EBET) and Enhanced EBET (EEBET). The first proposed protocol avoids direct transmission over long distance to save sufficient amount of energy consumed in the routing process. The second protocol overcomes the deficiencies in both Balanced Transmission Mechanism (BTM) and EBET techniques. EBET selects relay node on the basis of optimal distance threshold which leads to network lifetime prolongation. The initial energy of each sensor node is divided into energy levels for balanced energy consumption. Selection of high energy level node within transmission range avoids long distance direct data transmission. The EEBET incorporates depth threshold to minimize the number of hops between source node and sink while eradicating backward data transmissions. The EBET technique balances energy consumption within successive ring sectors, while, EEBET balances energy consumption of the entire network. In EEBET, optimum number of energy levels are also calculated to further enhance the network lifetime. Effectiveness of the proposed schemes is validated through simulations where these are compared with two existing routing protocols in terms of network lifetime, transmission loss, and throughput. The simulations are conducted under different network radii and varied number of nodes. PMID:27070605

  19. Influence of the vibro-acoustic sensor position on cavitation detection in a Kaplan turbine

    NASA Astrophysics Data System (ADS)

    Schmidt, H.; Kirschner, O.; Riedelbauch, S.; Necker, J.; Kopf, E.; Rieg, M.; Arantes, G.; Wessiak, M.; Mayrhuber, J.

    2014-03-01

    Hydraulic turbines can be operated close to the limits of the operating range to meet the demand of the grid. When operated close to the limits, the risk increases that cavitation phenomena may occur at the runner and / or at the guide vanes of the turbine. Cavitation in a hydraulic turbine can cause material erosion on the runner and other turbine parts and reduce the durability of the machine leading to required outage time and related repair costs. Therefore it is important to get reliable information about the appearance of cavitation during prototype operation. In this experimental investigation the high frequency acoustic emissions and vibrations were measured at 20 operating points with different cavitation behaviour at different positions in a large prototype Kaplan turbine. The main goal was a comparison of the measured signals at different sensor positions to identify the sensitivity of the location for cavitation detection. The measured signals were analysed statistically and specific values were derived. Based on the measured signals, it is possible to confirm the cavitation limit of the examined turbine. The result of the investigation shows that the position of the sensors has a significant influence on the detection of cavitation.

  20. An Enhanced Energy Balanced Data Transmission Protocol for Underwater Acoustic Sensor Networks.

    PubMed

    Javaid, Nadeem; Shah, Mehreen; Ahmad, Ashfaq; Imran, Muhammad; Khan, Majid Iqbal; Vasilakos, Athanasios V

    2016-01-01

    This paper presents two new energy balanced routing protocols for Underwater Acoustic Sensor Networks (UASNs); Efficient and Balanced Energy consumption Technique (EBET) and Enhanced EBET (EEBET). The first proposed protocol avoids direct transmission over long distance to save sufficient amount of energy consumed in the routing process. The second protocol overcomes the deficiencies in both Balanced Transmission Mechanism (BTM) and EBET techniques. EBET selects relay node on the basis of optimal distance threshold which leads to network lifetime prolongation. The initial energy of each sensor node is divided into energy levels for balanced energy consumption. Selection of high energy level node within transmission range avoids long distance direct data transmission. The EEBET incorporates depth threshold to minimize the number of hops between source node and sink while eradicating backward data transmissions. The EBET technique balances energy consumption within successive ring sectors, while, EEBET balances energy consumption of the entire network. In EEBET, optimum number of energy levels are also calculated to further enhance the network lifetime. Effectiveness of the proposed schemes is validated through simulations where these are compared with two existing routing protocols in terms of network lifetime, transmission loss, and throughput. The simulations are conducted under different network radii and varied number of nodes. PMID:27070605

  1. A surface acoustic wave sensor functionalized with a polypyrrole molecularly imprinted polymer for selective dopamine detection.

    PubMed

    Maouche, Naima; Ktari, Nadia; Bakas, Idriss; Fourati, Najla; Zerrouki, Chouki; Seydou, Mahamadou; Maurel, François; Chehimi, Mohammed Mehdi

    2015-11-01

    A surface acoustic wave sensor operating at 104 MHz and functionalized with a polypyrrole molecularly imprinted polymer has been designed for selective detection of dopamine (DA). Optimization of pyrrole/DA ratio, polymerization and immersion times permitted to obtain a highly selective sensor, which has a sensitivity of 0.55°/mM (≈ 550 Hz/mM) and a detection limit of ≈ 10 nM. Morphology and related roughness parameters of molecularly imprinted polymer surfaces, before and after extraction of DA, as well as that of the non imprinted polymer were characterized by atomic force microscopy. The developed chemosensor selectively recognized dopamine over the structurally similar compound 4-hydroxyphenethylamine (referred as tyramine), or ascorbic acid,which co-exists with DA in body fluids at a much higher concentration. Selectivity tests were also carried out with dihydroxybenzene, for which an unexpected phase variation of order of 75% of the DA one was observed. Quantum chemical calculations, based on the density functional theory, were carried out to determine the nature of interactions between each analyte and the PPy matrix and the DA imprinted PPy polypyrrole sensing layer in order to account for the important phase variation observed during dihydroxybenzene injection. PMID:26095144

  2. Energy balanced strategies for maximizing the lifetime of sparsely deployed underwater acoustic sensor networks.

    PubMed

    Luo, Hanjiang; Guo, Zhongwen; Wu, Kaishun; Hong, Feng; Feng, Yuan

    2009-01-01

    Underwater acoustic sensor networks (UWA-SNs) are envisioned to perform monitoring tasks over the large portion of the world covered by oceans. Due to economics and the large area of the ocean, UWA-SNs are mainly sparsely deployed networks nowadays. The limited battery resources is a big challenge for the deployment of such long-term sensor networks. Unbalanced battery energy consumption will lead to early energy depletion of nodes, which partitions the whole networks and impairs the integrity of the monitoring datasets or even results in the collapse of the entire networks. On the contrary, balanced energy dissipation of nodes can prolong the lifetime of such networks. In this paper, we focus on the energy balance dissipation problem of two types of sparsely deployed UWA-SNs: underwater moored monitoring systems and sparsely deployed two-dimensional UWA-SNs. We first analyze the reasons of unbalanced energy consumption in such networks, then we propose two energy balanced strategies to maximize the lifetime of networks both in shallow and deep water. Finally, we evaluate our methods by simulations and the results show that the two strategies can achieve balanced energy consumption per node while at the same time prolong the networks lifetime. PMID:22399970

  3. Temperature compensation of ball surface acoustic wave sensor by two-frequency measurement using undersampling

    NASA Astrophysics Data System (ADS)

    Tsuji, Toshihiro; Oizumi, Toru; Takeda, Nobuo; Akao, Shingo; Tsukahara, Yusuke; Yamanaka, Kazushi

    2015-07-01

    To realize a practical two-frequency measurement (TFM) system for precise temperature compensation in a ball surface acoustic wave (SAW) sensor, the application of undersampling (US) was investigated. The subtraction coefficient for the temperature compensation in US was theoretically explained. The principle of the TFM system using US was simulated by the decimation of the oversampling (OS) waveform after applying a narrow band-pass filter, and the delay time was measured using a wavelet transform. In the application of the method to trace moisture measurement, the delay time response due to US matched that due to OS with a correlation coefficient higher than 0.9999. Although rms noise was increased by US, the response to the concentration change of 4-17 nmol/mol was measured with a signal-to-noise ratio higher than 20. From these results, it was shown that the precise output of the ball SAW sensor could be obtained even when using US, which was equivalent to that using OS.

  4. Monolithic active pixel sensors (MAPS) in a VLSI CMOS technology

    NASA Astrophysics Data System (ADS)

    Turchetta, R.; French, M.; Manolopoulos, S.; Tyndel, M.; Allport, P.; Bates, R.; O'Shea, V.; Hall, G.; Raymond, M.

    2003-03-01

    Monolithic Active Pixel Sensors (MAPS) designed in a standard VLSI CMOS technology have recently been proposed as a compact pixel detector for the detection of high-energy charged particle in vertex/tracking applications. MAPS, also named CMOS sensors, are already extensively used in visible light applications. With respect to other competing imaging technologies, CMOS sensors have several potential advantages in terms of low cost, low power, lower noise at higher speed, random access of pixels which allows windowing of region of interest, ability to integrate several functions on the same chip. This brings altogether to the concept of 'camera-on-a-chip'. In this paper, we review the use of CMOS sensors for particle physics and we analyse their performances in term of the efficiency (fill factor), signal generation, noise, readout speed and sensor area. In most of high-energy physics applications, data reduction is needed in the sensor at an early stage of the data processing before transfer of the data to tape. Because of the large number of pixels, data reduction is needed on the sensor itself or just outside. This brings in stringent requirements on the temporal noise as well as to the sensor uniformity, expressed as a Fixed Pattern Noise (FPN). A pixel architecture with an additional transistor is proposed. This architecture, coupled to correlated double sampling of the signal will allow cancellation of the two dominant noise sources, namely the reset or kTC noise and the FPN. A prototype has been designed in a standard 0.25 μm CMOS technology. It has also a structure for electrical calibration of the sensor. The prototype is functional and detailed tests are under way.

  5. Modeling, design, packing and experimental analysis of liquid-phase shear-horizontal surface acoustic wave sensors

    NASA Astrophysics Data System (ADS)

    Pollard, Thomas B

    Recent advances in microbiology, computational capabilities, and microelectromechanical-system fabrication techniques permit modeling, design, and fabrication of low-cost, miniature, sensitive and selective liquid-phase sensors and lab-on-a-chip systems. Such devices are expected to replace expensive, time-consuming, and bulky laboratory-based testing equipment. Potential applications for devices include: fluid characterization for material science and industry; chemical analysis in medicine and pharmacology; study of biological processes; food analysis; chemical kinetics analysis; and environmental monitoring. When combined with liquid-phase packaging, sensors based on surface-acoustic-wave (SAW) technology are considered strong candidates. For this reason such devices are focused on in this work; emphasis placed on device modeling and packaging for liquid-phase operation. Regarding modeling, topics considered include mode excitation efficiency of transducers; mode sensitivity based on guiding structure materials/geometries; and use of new piezoelectric materials. On packaging, topics considered include package interfacing with SAW devices, and minimization of packaging effects on device performance. In this work novel numerical models are theoretically developed and implemented to study propagation and transduction characteristics of sensor designs using wave/constitutive equations, Green's functions, and boundary/finite element methods. Using developed simulation tools that consider finite-thickness of all device electrodes, transduction efficiency for SAW transducers with neighboring uniform or periodic guiding electrodes is reported for the first time. Results indicate finite electrode thickness strongly affects efficiency. Using dense electrodes, efficiency is shown to approach 92% and 100% for uniform and periodic electrode guiding, respectively; yielding improved sensor detection limits. A numerical sensitivity analysis is presented targeting viscosity

  6. Seaborne electro-optical sensors and their technologies

    NASA Astrophysics Data System (ADS)

    Horman, Stephen R.; Headley, Robert M., Jr.; Zurasky, Matthew W.; Dezeeuw, Patrick A.; Trahan, Joseph W.

    1999-07-01

    The US Navy (USN) has long placed a strong emphasis on the production and use of electro-optical (EO) sensors for a wide variety of mission on naval aircraft. Numerous EO fire control and surveillance sensor systems have been developed for USN surface ship applications, but production and deployment has been limited. This apparent dichotomy is due to the vastly different missions and environments of aircraft and ships, and to the need for shipboard system that will support operations dictated by our global interest. EO technology has now evolved to the point where surveillance and fire control sensor systems can be built that have excellent performance under the preponderance of environmental conditions, and where atmospheric refraction, rather than transmission, is the primary design driver. In addition, the consensus of USN decision-makers is that EO sensor system that are designed to complement not supplant, radar systems can provide dramatic improvements in combat system performance at acceptable costs. The two sensor classes that have achieved this level of maturity are Horizon IR Surveillance Systems and the Thermal Imaging Sensors. This paper describes the technologies that have made these sensors possible as well as some of the phenomenological drivers to their designs.

  7. High signal-to-noise ratio acoustic sensor using phase shifted gratings interrogated by the Pound-Drever-Hall technique

    NASA Astrophysics Data System (ADS)

    Kung, Peter; Comanici, Maria I.

    2015-03-01

    Optical fiber is made of glass, an insulator, and thus it is immune to strong electromagnetic interference. Therefore, fiber optics is a technology ideally suitable for sensing of partial discharge (PD) both in transformers and generators. Extensive efforts have been used to develop a cost effective solution for detecting partial discharge, which generates acoustic emission, with signals ranging from 30 kHz to 200 kHz. The requirement is similar to fiber optics Hydro Phone, but at higher frequencies. There are several keys to success: there must be at least 60 dB signal-to-noise ratio (SNR) performance, which will ensure not only PD detection but later on provide diagnostics and also the ability to locate the origin of the events. Defects that are stationary would gradually degrade the insulation and result in total breakdown. Transformers currently need urgent attention: most of them are oil filled and are at least 30 to 50 years old, close to the end of life. In this context, an issue to be addressed is the safety of the personnel working close to the assets and collateral damage that could be caused by a tank explosion (with fire spilling over the whole facility). This paper will describe the latest achievement in fiber optics PD sensor technology: the use of phase shifted-fiber gratings with a very high speed interrogation method that uses the Pound-Drever-Hall technique. More importantly, this is based on a technology that could be automated, easy to install, and, eventually, available at affordable prices.

  8. High signal-to-noise acoustic sensor using phase-shifted gratings interrogated by the Pound-Drever-Hall technique

    NASA Astrophysics Data System (ADS)

    Kung, Peter; Comanici, Maria I.

    2014-11-01

    Optical fiber is made of glass, an insulator, and thus it is immune to strong electromagnetic interference. Therefore, fiber optics is a technology ideally suitable for sensing of partial discharge (PD) both in transformers and generators. Extensive efforts have been used to develop a cost effective solution for detecting partial discharge, which generates acoustic emission, with signals ranging from 30 kHz to 200 kHz. The requirement is similar to fiber optics Hydro Phone, but at higher frequencies. There are several keys to success: there must be at least 60 dB signal-to-noise ratio (SNR) performance, which will ensure not only PD detection but later on provide diagnostics and also the ability to locate the origin of the events. Defects that are stationary would gradually degrade the insulation and result in total breakdown. Transformers currently need urgent attention: most of them are oil filled and are at least 30 to 50 years old, close to the end of life. In this context, an issue to be addressed is the safety of the personnel working close to the assets and collateral damage that could be caused by a tank explosion (with fire spilling over the whole facility). This paper will describe the latest achievement in fiber optics PD sensor technology: the use of phase shifted-fiber gratings with a very high speed interrogation method that uses the Pound-Drever-Hall technique. More importantly, this is based on a technology that could be automated, easy to install, and, eventually, available at affordable prices.

  9. Micro-optics technology and sensor systems applications

    NASA Technical Reports Server (NTRS)

    Gal, George; Herman, B.; Anderson, W.; Whitney, R.; Morrow, H.

    1993-01-01

    The current generation of electro-optical sensors utilizing refractive and reflective optical elements require sophisticated, complex, and expensive designs. Advanced-technology-based electro-optical sensors of minimum size and weight require miniaturization of optical, electrical, and mechanical devices with an increasing trend toward integration of various components. Micro-optics technology has the potential in a number of areas to simplify optical design with improved performance. This includes internally cooled apertures, hybrid optical design, microlenses, dispersive multicolor microlenses, active dither, electronically controlled optical beam steer, and microscopic integration of micro-optics, detectors, and signal processing layers. This paper describes our approach to the development of micro-optics technology with our main emphasis for sensors applications.

  10. Blue sensors : technology and cooperative monitoring in UN peacekeeping.

    SciTech Connect

    Dorn, A. Walter Dr.

    2004-04-01

    For over a half-century, the soldiers and civilians deployed to conflict areas in UN peacekeeping operations have monitored ceasefires and peace agreements of many types with varying degrees of effectiveness. Though there has been a significant evolution of peacekeeping, especially in the 1990s, with many new monitoring functions, the UN has yet to incorporate monitoring technologies into its operations in a systematic fashion. Rather, the level of technology depends largely on the contributing nations and the individual field commanders. In most missions, sensor technology has not been used at all. So the UN has not been able to fully benefit from the sensor technology revolution that has seen effectiveness greatly amplified and costs plummet. This paper argues that monitoring technologies need not replace the human factor, which is essential for confidence building in conflict areas, but they can make peacekeepers more effective, more knowledgeable and safer. Airborne, ground and underground sensors can allow peacekeepers to do better monitoring over larger areas, in rugged terrain, at night (when most infractions occur) and in adverse weather conditions. Technology also allows new ways to share gathered information with the parties to create confidence and, hence, better pre-conditions for peace. In the future sensors should become 'tools of the trade' to help the UN keep the peace in war-torn areas.

  11. Network of acoustic sensors for the detection of weapons firing: tests for the choice of individual sensing elements

    NASA Astrophysics Data System (ADS)

    Naz, P.; Marty, Ch.; Hengy, S.; Hamery, P.

    2010-04-01

    The detection and localization of weapon firing on the battlefield is envisaged by means of acoustic waves. The main objective of this work is to compare various sensing elements that can be integrated in acoustic arrays. Experimental measurements of sound waves obtained by using some of these elements in Unattended Ground Sensors are presented for snipers, mortars or artillery guns. The emphasis will be put on the characteristics of the sensing elements needed to detect and classify the Mach wave generated by a supersonic projectile and the muzzle wave generated by the combustion of the propulsion powder. Examples of preliminary prototypes are presented to illustrate our topic. We will concentrate on a wearable system considered to improve the soldier's awareness of the surrounding threats: this realization consists of a network of three helmets integrating an acoustic array for the detection and localization of snipers.

  12. A microfabricated electron-tunneling accelerometer as a directional underwater acoustic sensor

    SciTech Connect

    Rockstad, H.K.; Kenny, T.W.; Kelly, P.J.; Gabrielson, T.B.

    1996-04-01

    Microfabricated accelerometers have been developed for a wide variety of applications; however, the principal commercial focus has been on signal detection in the milli-g to tens or hundreds of g accelerations. The development of a microfabricated device to detect accelerations in the 10 to 100 nano-g range is a substantial technological challenge because of the conflict between the required increase in mass (and reduction in suspension stiffness) and the small volume. In an underwater sensor, designed to be nearly neutrally buoyant, there are additional restrictions on the packaging of the sensor with regard to overall density, resistance to hydrostatic pressure, and flexibility of power and signal leads. The design goal of this project is to demonstrate a two-axis sensor in an 8 cm{sup 3} (and 8 gram) package capable of immersion to 600 meters. The sensor must have a self noise below 100 nano-g per root hertz from 5 to 1000 Hz. Several of these requirements have been demonstrated with an accelerometer structure based on electron tunneling and microfabricated from single-crystal silicon. The electron-tunneling transduction mechanism provides an inherently large transduction constant (although at the expense of requiring closed-loop control) and is readily adapted to batch fabrication in silicon. {copyright} {ital 1996 American Institute of Physics.}

  13. Monitoring and Failure Analysis of Corroded Bridge Cables under Fatigue Loading Using Acoustic Emission Sensors

    PubMed Central

    Li, Dongsheng; Ou, Jinping; Lan, Chengming; Li, Hui

    2012-01-01

    Cables play an important role in cable-stayed systems, but are vulnerable to corrosion and fatigue damage. There is a dearth of studies on the fatigue damage evolution of corroded cable. In the present study, the acoustic emission (AE) technology is adopted to monitor the fatigue damage evolution process. First, the relationship between stress and strain is determined through a tensile test for corroded and non-corroded steel wires. Results show that the mechanical performance of corroded cables is changed considerably. The AE characteristic parameters for fatigue damage are then established. AE energy cumulative parameters can accurately describe the fatigue damage evolution of corroded cables. The failure modes in each phase as well as the type of acoustic emission source are determined based on the results of scanning electron microscopy. The waveform characteristics, damage types, and frequency distribution of the corroded cable at different damage phases are collected. Finally, the number of broken wires and breakage time of the cables are determined according to the variation in the margin index. PMID:22666009

  14. Monitoring and failure analysis of corroded bridge cables under fatigue loading using acoustic emission sensors.

    PubMed

    Li, Dongsheng; Ou, Jinping; Lan, Chengming; Li, Hui

    2012-01-01

    Cables play an important role in cable-stayed systems, but are vulnerable to corrosion and fatigue damage. There is a dearth of studies on the fatigue damage evolution of corroded cable. In the present study, the acoustic emission (AE) technology is adopted to monitor the fatigue damage evolution process. First, the relationship between stress and strain is determined through a tensile test for corroded and non-corroded steel wires. Results show that the mechanical performance of corroded cables is changed considerably. The AE characteristic parameters for fatigue damage are then established. AE energy cumulative parameters can accurately describe the fatigue damage evolution of corroded cables. The failure modes in each phase as well as the type of acoustic emission source are determined based on the results of scanning electron microscopy. The waveform characteristics, damage types, and frequency distribution of the corroded cable at different damage phases are collected. Finally, the number of broken wires and breakage time of the cables are determined according to the variation in the margin index. PMID:22666009

  15. 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. PMID:25624226

  16. Self-adapting root-MUSIC algorithm and its real-valued formulation for acoustic vector sensor array

    NASA Astrophysics Data System (ADS)

    Wang, Peng; Zhang, Guo-jun; Xue, Chen-yang; Zhang, Wen-dong; Xiong, Ji-jun

    2012-12-01

    In this paper, based on the root-MUSIC algorithm for acoustic pressure sensor array, a new self-adapting root-MUSIC algorithm for acoustic vector sensor array is proposed by self-adaptive selecting the lead orientation vector, and its real-valued formulation by Forward-Backward(FB) smoothing and real-valued inverse covariance matrix is also proposed, which can reduce the computational complexity and distinguish the coherent signals. The simulation experiment results show the better performance of two new algorithm with low Signal-to-Noise (SNR) in direction of arrival (DOA) estimation than traditional MUSIC algorithm, and the experiment results using MEMS vector hydrophone array in lake trails show the engineering practicability of two new algorithms.

  17. Resonant Magnetic Field Sensors Based On MEMS Technology.

    PubMed

    Herrera-May, Agustín L; Aguilera-Cortés, Luz A; García-Ramírez, Pedro J; Manjarrez, Elías

    2009-01-01

    Microelectromechanical systems (MEMS) technology allows the integration of magnetic field sensors with electronic components, which presents important advantages such as small size, light weight, minimum power consumption, low cost, better sensitivity and high resolution. We present a discussion and review of resonant magnetic field sensors based on MEMS technology. In practice, these sensors exploit the Lorentz force in order to detect external magnetic fields through the displacement of resonant structures, which are measured with optical, capacitive, and piezoresistive sensing techniques. From these, the optical sensing presents immunity to electromagnetic interference (EMI) and reduces the read-out electronic complexity. Moreover, piezoresistive sensing requires an easy fabrication process as well as a standard packaging. A description of the operation mechanisms, advantages and drawbacks of each sensor is considered. MEMS magnetic field sensors are a potential alternative for numerous applications, including the automotive industry, military, medical, telecommunications, oceanographic, spatial, and environment science. In addition, future markets will need the development of several sensors on a single chip for measuring different parameters such as the magnetic field, pressure, temperature and acceleration. PMID:22408480

  18. Resonant Magnetic Field Sensors Based On MEMS Technology

    PubMed Central

    Herrera-May, Agustín L.; Aguilera-Cortés, Luz A.; García-Ramírez, Pedro J.; Manjarrez, Elías

    2009-01-01

    Microelectromechanical systems (MEMS) technology allows the integration of magnetic field sensors with electronic components, which presents important advantages such as small size, light weight, minimum power consumption, low cost, better sensitivity and high resolution. We present a discussion and review of resonant magnetic field sensors based on MEMS technology. In practice, these sensors exploit the Lorentz force in order to detect external magnetic fields through the displacement of resonant structures, which are measured with optical, capacitive, and piezoresistive sensing techniques. From these, the optical sensing presents immunity to electromagnetic interference (EMI) and reduces the read-out electronic complexity. Moreover, piezoresistive sensing requires an easy fabrication process as well as a standard packaging. A description of the operation mechanisms, advantages and drawbacks of each sensor is considered. MEMS magnetic field sensors are a potential alternative for numerous applications, including the automotive industry, military, medical, telecommunications, oceanographic, spatial, and environment science. In addition, future markets will need the development of several sensors on a single chip for measuring different parameters such as the magnetic field, pressure, temperature and acceleration. PMID:22408480

  19. Stage acoustics for musicians: A multidimensional approach using 3D ambisonic technology

    NASA Astrophysics Data System (ADS)

    Guthrie, Anne

    In this research, a method was outlined and tested for the use of 3D Ambisonic technology to inform stage acoustics research and design. Stage acoustics for musicians as a field has yet to benefit from recent advancements in auralization and spatial acoustic analysis. This research attempts to address common issues in stage acoustics: subjective requirements for performers in relation to feelings of support, quality of sound, and ease of ensemble playing in relation to measurable, objective characteristics that can be used to design better stage enclosures. While these issues have been addressed in previous work, this research attempts to use technological advancements to improve the resolution and realism of the testing and analysis procedures. Advancements include measurement of spatial impulse responses using a spherical microphone array, higher-order ambisonic encoding and playback for real-time performer auralization, high-resolution spatial beamforming for analysis of onstage impulse responses, and multidimensional scaling procedures to determine subjective musician preferences. The methodology for implementing these technologies into stage acoustics research is outlined in this document and initial observations regarding implications for stage enclosure design are proposed. This research provides a robust method for measuring and analyzing performer experiences on multiple stages without the costly and time-intensive process of physically surveying orchestras on different stages, with increased repeatability while maintaining a high level of immersive realism and spatial resolution. Along with implications for physical design, this method provides possibilities for virtual teaching and rehearsal, parametric modeling and co-located performance.

  20. Characterization, monitoring, and sensor technology catalogue

    SciTech Connect

    Matalucci, R.V.; Esparza-Baca, C.; Jimenez, R.D.

    1995-12-01

    This document represents a summary of 58 technologies that are being developed by the Department of Energy`s (DOE`s) Office of Science and Technology (OST) to provide site, waste, and process characterization and monitoring solutions to the DOE weapons complex. The information was compiled to provide performance data on OST-developed technologies to scientists and engineers responsible for preparing Remedial Investigation/Feasibility Studies (RI/FSs) and preparing plans and compliance documents for DOE cleanup and waste management programs. The information may also be used to identify opportunities for partnering and commercialization with industry, DOE laboratories, other federal and state agencies, and the academic community. Each technology is featured in a format that provides: (1) a description, (2) technical performance data, (3) applicability, (4) development status, (5) regulatory considerations, (6) potential commercial applications, (7) intellectual property, and (8) points-of-contact. Technologies are categorized into the following areas: (1) Bioremediation Monitoring, (2) Decontamination and Decommissioning, (3) Field Analytical Laboratories, (4) Geophysical and Hydrologic Characterization, (5) Hazardous Inorganic Contaminant Analysis, (6) Hazardous Organic Contaminant Analysis, (7) Mixed Waste, (8) Radioactive Contaminant Analysis, (9) Remote Sensing,(10)Sampling and Drilling, (11) Statistically Guided Sampling, and (12) Tank Waste.

  1. Suspended particulate matter estimates using optical and acoustic sensors: application in Nestos River plume (Thracian Sea, North Aegean Sea).

    PubMed

    Anastasiou, Sotiria; Sylaios, Georgios K; Tsihrintzis, Vassilios A

    2015-06-01

    The present study investigates the use of combined methods of optical and acoustic sensors, in collaboration with direct in situ measurements, for the calibration and validation of a model transforming acoustic backscatter intensity series into suspended particulate matter (SPM) concentration datasets. The model follows previously elaborated techniques, placing particular attention to the parameterization of the acoustic absorption index as a function of water physical properties. Results were obtained from the annual deployment (during 2007-2008) of an upward-facing acoustic Doppler current profiler (ADCP) (307 kHz), equipped with a Wave Array, and an optical backscatter sensor (OBS), at the bottom of Thassos Passage near Nestos River plume (Thracian Sea, Northern Greece). The OBS was calibrated through linear regression, using 2007 and 2012 field sampling data, exhibiting an error of 13-14 % due to chlorophyll presence. The ADCP signal was calibrated through simultaneous measurements of backscatter intensity and turbidity profiles. Harmonic analysis on the model-produced SPM concentrations explained the tidal influence on their variability, especially during the summer. Empirical orthogonal functions analysis revealed the impact of waves and wave-induced currents on SPM variability. Finally, Nestos River sediment load was found uncorrelated to the SPM change in Thassos Passage, due to the dispersal and sediment deposition near the river mouth. PMID:26026846

  2. Investigation of the scaling rules determining the performance of film bulk acoustic resonators operating as mass sensors.

    PubMed

    Weber, Jan; Link, Mathias; Primig, Robert; Pitzer, Dana; Wersing, Wolfram; Schreiter, Matthias

    2007-02-01

    Solidly mounted (SMR-type) thin film bulk acoustic resonators operating at 2.2, 4.1, and 8.0 GHz and with lateral extents from 30 to 500 microm were fabricated and their performance as mass sensors was evaluated theoretically as well as experimentally. It was found that increasing the frequency leads to a principally improved performance of these devices. Problems arising for the horizontal as well as the vertical dimension and structure are investigated. PMID:17328337

  3. Development of a hydrogen gas sensor using microfabrication technology

    NASA Technical Reports Server (NTRS)

    Liu, Chung-Chiun; Wu, Qinghai; Stuczynski, Matthew; Madzsar, George C.

    1992-01-01

    Microfabrication and micromachining technologies are used to produce a hydrogen gas sensor based on a palladium-silver film. The sensor uses a heater that is fabricated by diffusing p-type borones into the substrate, forming a resistance heater. A diode for temperature measurement is produced using p-type boron and n-type phosphor diffused into the substrate. A thickness of the palladium-silver film is approximately 300 arcsec. The hydrogen gas sensor employs the proven palladium-silver diode structure and is surrounded by a phosphor doped resistance heater which can be heated up to a temperature of 250 C. Experimental results show that the sensor is capable of operating over a wide range of hydrogen concentration levels between 0-95 percent without any hysteresis effects.

  4. Using a fibre-optic cable as Distributed Acoustic Sensor for Vertical Seismic Profiling - Overview of various field tests

    NASA Astrophysics Data System (ADS)

    Götz, Julia; Lüth, Stefan; Henninges, Jan; Reinsch, Thomas

    2015-04-01

    Fibre-optic Distributed Acoustic Sensing (DAS) or Distributed Vibration Sensing (DVS) is a technology, where an optical fibre cable is used as a sensor for acoustic signals. An ambient seismic wavefield, which is coupled by friction or pressure to the optical fibre, induces dynamic strain changes along the cable. The DAS/DVS technology offers the possibility to record an optoelectronic signal which is linearly related to the time dependent local strain. The DAS/DVS technology is based on the established technique of phase-sensitive optical time-domain reflectometry (phi-OTDR). Coherent laser pulses are launched into the fibre to monitor changes in the resulting elastic Rayleigh backscatter with time. Dynamic strain changes lead to small displacements of the scattering elements (non-uniformities within the glass structure of the optical fibre), and therefore to variations of the relative phases of the backscattered photons. The fibre behaves as a series of interferometers whose output is sensitive to small changes of the strain at any point along its length. To record the ground motion not only in space but also in time, snapshots of the wavefield are created by repeatedly firing laser pulses into the fibre at sampling frequencies much higher than seismic frequencies. DAS/DVS is used e.g. for continuous monitoring of pipelines, roads or borders and for production monitoring from within the wellbore. Within the last years, the DAS/DVS technology was further developed to record seismic data. We focus on the recording of Vertical Seismic Profiling (VSP) data with DAS/DVS and present an overview of various field tests published between 2011 and 2014. Here, especially CO2 storage pilot sites provided the opportunity to test this new technology for geophysical reservoir monitoring. DAS/DVS-VSP time-lapse measurements have been published for the Quest CO2 storage site in Canada. The DAS/DVS technology was also tested at the CO2 storage sites in Rousse (France), Citronelle

  5. Clinical Studies of Real-Time Monitoring of Lithotripter Performance Using Passive Acoustic Sensors

    NASA Astrophysics Data System (ADS)

    Leighton, T. G.; Fedele, F.; Coleman, A. J.; McCarthy, C.; Ryves, S.; Hurrell, A. M.; De Stefano, A.; White, P. R.

    2008-09-01

    ), comparison of the opinion of the urologist at follow-up with the acoustically derived judgment identified a good correlation (kappa = 0.94), the device demonstrating a sensitivity of 91.7% (in that it correctly predicted 11 of the 12 treatments which the urologist stated had been `successful' at the 3-week follow-up), and a specificity of 100% (in that it correctly predicted all of the 37 treatments which the urologist stated had been `unsuccessful' at the 3-week follow-up). The `gold standard' opinion of the urologist (CTS2) correlated poorly (kappa = 0.38) with the end-of-treatment opinion of the radiographer (CTS1). This is due to the limited resolution of the lithotripter X-Ray fluoroscopy system. If the results of phase 1 and phase 2 are pooled to form a dataset against which retrospectively to test the rules drawn up in phase 1, when compared with the gold standard CTS2, over the two clinical trials (79 patients) the device-derived scored (TS0) correctly predicted the clinical effectiveness of the treatment for 78 for the 79 patients (the error occurred on a difficult patient with a high body mass index). In comparison, using the currently available technology the in-theatre clinician (the radiographer) provided a treatment score CTS1 which correctly predicted the outcome of only 61 of the 79 therapies. In particular the passive acoustic device correctly predicted 18 of the 19 treatments that were successful (i.e. 94.7 sensitivity), whilst the current technology enabled the in-theatre radiographer to predict only 7 of the 19 successful treatments (i.e. 36.8 sensitivity). The real-time capabilities of the device were used in a preliminary examination of the effect of ventilation.

  6. Benthic microbial fuel cell as direct power source for an acoustic modem and seawater oxygen/temperature sensor system.

    PubMed

    Gong, Yanming; Radachowsky, Sage E; Wolf, Michael; Nielsen, Mark E; Girguis, Peter R; Reimers, Clare E

    2011-06-01

    Supported by the natural potential difference between anoxic sediment and oxic seawater, benthic microbial fuel cells (BMFCs) promise to be ideal power sources for certain low-power marine sensors and communication devices. In this study a chambered BMFC with a 0.25 m(2) footprint was used to power an acoustic modem interfaced with an oceanographic sensor that measures dissolved oxygen and temperature. The experiment was conducted in Yaquina Bay, Oregon over 50 days. Several improvements were made in the BMFC design and power management system based on lessons learned from earlier prototypes. The energy was harvested by a dynamic gain charge pump circuit that maintains a desired point on the BMFC's power curve and stores the energy in a 200 F supercapacitor. The system also used an ultralow power microcontroller and quartz clock to read the oxygen/temperature sensor hourly, store data with a time stamp, and perform daily polarizations. Data records were transmitted to the surface by the acoustic modem every 1-5 days after receiving an acoustic prompt from a surface hydrophone. After jump-starting energy production with supplemental macroalgae placed in the BMFC's anode chamber, the average power density of the BMFC adjusted to 44 mW/m(2) of seafloor area which is better than past demonstrations at this site. The highest power density was 158 mW/m(2), and the useful energy produced and stored was ≥ 1.7 times the energy required to operate the system. PMID:21545151

  7. Open-circuit sensitivity model based on empirical parameters for a capacitive-type MEMS acoustic sensor

    NASA Astrophysics Data System (ADS)

    Lee, Jaewoo; Jeon, J. H.; Je, C. H.; Lee, S. Q.; Yang, W. S.; Lee, S.-G.

    2016-03-01

    An empirical-based open-circuit sensitivity model for a capacitive-type MEMS acoustic sensor is presented. To intuitively evaluate the characteristic of the open-circuit sensitivity, the empirical-based model is proposed and analysed by using a lumped spring-mass model and a pad test sample without a parallel plate capacitor for the parasitic capacitance. The model is composed of three different parameter groups: empirical, theoretical, and mixed data. The empirical residual stress from the measured pull-in voltage of 16.7 V and the measured surface topology of the diaphragm were extracted as +13 MPa, resulting in the effective spring constant of 110.9 N/m. The parasitic capacitance for two probing pads including the substrate part was 0.25 pF. Furthermore, to verify the proposed model, the modelled open-circuit sensitivity was compared with the measured value. The MEMS acoustic sensor had an open- circuit sensitivity of -43.0 dBV/Pa at 1 kHz with a bias of 10 V, while the modelled open- circuit sensitivity was -42.9 dBV/Pa, which showed good agreement in the range from 100 Hz to 18 kHz. This validates the empirical-based open-circuit sensitivity model for designing capacitive-type MEMS acoustic sensors.

  8. Sensor Technology for Integrated Vehicle Health Management of Aerospace Vehicles

    NASA Technical Reports Server (NTRS)

    Prosser, W. H.; Brown, T. L.; Woodard, S. E.; Fleming, G. A.; Cooper, E. G.

    2002-01-01

    NASA is focusing considerable efforts on technology development for Integrated Vehicle Health Management systems. The research in this area is targeted toward increasing aerospace vehicle safety and reliability, while reducing vehicle operating and maintenance costs. Onboard, real-time sensing technologies that can provide detailed information on structural integrity are central to such a health management system. This paper describes a number of sensor technologies currently under development for integrated vehicle health management. The capabilities, current limitations, and future research needs of these technologies are addressed.

  9. Active control of acoustic pressure fields using smart material technologies

    NASA Technical Reports Server (NTRS)

    Banks, H. T.; Smith, R. C.

    1993-01-01

    An overview describing the use of piezoceramic patches in reducing noise in a structural acoustics setting is presented. The passive and active contributions due to patches which are bonded to an Euler-Bernoulli beam or thin shell are briefly discussed and the results are incorporated into a 2-D structural acoustics model. In this model, an exterior noise source causes structural vibrations which in turn lead to interior noise as a result of nonlinear fluid/structure coupling mechanism. Interior sound pressure levels are reduced via patches bonded to the flexible boundary (a beam in this case) which generate pure bending moments when an out-of-phase voltage is applied. Well-posedness results for the infinite dimensional system are discussed and a Galerkin scheme for approximating the system dynamics is outlined. Control is implemented by using linear quadratic regulator (LQR) optimal control theory to calculate gains for the linearized system and then feeding these gains back into the nonlinear system of interest. The effectiveness of this strategy for this problem is illustrated in an example.

  10. Deciphering acoustic emission signals in drought stressed branches: the missing link between source and sensor.

    PubMed

    Vergeynst, Lidewei L; Sause, Markus G R; Hamstad, Marvin A; Steppe, Kathy

    2015-01-01

    When drought occurs in plants, acoustic emission (AE) signals can be detected, but the actual causes of these signals are still unknown. By analyzing the waveforms of the measured signals, it should, however, be possible to trace the characteristics of the AE source and get information about the underlying physiological processes. A problem encountered during this analysis is that the waveform changes significantly from source to sensor and lack of knowledge on wave propagation impedes research progress made in this field. We used finite element modeling and the well-known pencil lead break source to investigate wave propagation in a branch. A cylindrical rod of polyvinyl chloride was first used to identify the theoretical propagation modes. Two wave propagation modes could be distinguished and we used the finite element model to interpret their behavior in terms of source position for both the PVC rod and a wooden rod. Both wave propagation modes were also identified in drying-induced signals from woody branches, and we used the obtained insights to provide recommendations for further AE research in plant science. PMID:26191070

  11. Evaluating damage potential of cryogenic concrete using acoustic emission sensors and permeability testing

    NASA Astrophysics Data System (ADS)

    Kogbara, Reginald B.; Parsaei, Boback; Iyengar, Srinath R.; Grasley, Zachary C.; Masad, Eyad A.; Zollinger, Dan G.

    2014-04-01

    This study evaluates the damage potential of concrete of different mix designs subjected to cryogenic temperatures, using acoustic emission (AE) and permeability testing. The aim is to investigate design methodologies that might be employed to produce concrete that resists damage when cooled to cryogenic temperatures. Such concrete would be suitable for primary containment of liquefied natural gas (LNG) and could replace currently used 9% Ni steel, thereby leading to huge cost savings. In the experiments described, concrete cubes, 150 mm x 150 mm x 150 mm, were cast using four different mix designs. The four mixes employed siliceous river sand as fine aggregate. Moreover, limestone, sandstone, trap rock and lightweight aggregate were individually used as coarse aggregates in the mixes. The concrete samples were then cooled from room temperature (20°C) to cryogenic temperature (-165°C) in a temperature chamber. AE sensors were placed on the concrete cubes during the cryogenic freezing process. The damage potential was evaluated in terms of the growth of damage as determined from AE, as a function of temperature and concrete mixture design. The damage potential observed was validated with water permeability testing. Initial results demonstrate the effects of the coefficient of thermal expansion (CTE) of the aggregates on damage growth. Concrete damage (cracking) resistance generally decreased with increasing coarse aggregate CTE, and was in the order, limestone ≥ trap rock << lightweight aggregate ≥ sandstone. Work is in progress to fully understand thermal dilation and damage growth in concrete due to differential CTE of its components.

  12. 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.

  13. Evaluation of MPEG-7-Based Audio Descriptors for Animal Voice Recognition over Wireless Acoustic Sensor Networks

    PubMed Central

    Luque, Joaquín; Larios, Diego F.; Personal, Enrique; Barbancho, Julio; León, Carlos

    2016-01-01

    Environmental audio monitoring is a huge area of interest for biologists all over the world. This is why some audio monitoring system have been proposed in the literature, which can be classified into two different approaches: acquirement and compression of all audio patterns in order to send them as raw data to a main server; or specific recognition systems based on audio patterns. The first approach presents the drawback of a high amount of information to be stored in a main server. Moreover, this information requires a considerable amount of effort to be analyzed. The second approach has the drawback of its lack of scalability when new patterns need to be detected. To overcome these limitations, this paper proposes an environmental Wireless Acoustic Sensor Network architecture focused on use of generic descriptors based on an MPEG-7 standard. These descriptors demonstrate it to be suitable to be used in the recognition of different patterns, allowing a high scalability. The proposed parameters have been tested to recognize different behaviors of two anuran species that live in Spanish natural parks; the Epidalea calamita and the Alytes obstetricans toads, demonstrating to have a high classification performance. PMID:27213375

  14. 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

  15. Biomass of zooplankton estimated by acoustical sensors in the Arabian sea. Final report

    SciTech Connect

    Holliday, D.V.

    1996-11-22

    The long term goal of our overall research program is the development of data-based models to predict ecological relationships of zooplankton, phytoplankton and the physical environment in the sea. The overall objective of the work carried out within the scope of this particular contract was to acoustically measure the dynamics of zooplankton and micronekton in the northern Arabian Sea during several seasons. The scientific focus was to examine the impact, if any, of the two annual monsoons that are thought to drive the ecosystem response in the area. This particular project involved the design and construction of two sensors which were then deployed in the Arabian Sea by several of our co-PIVs in the ONR ARI on Forced Upper Ocean Dynamics during the time period in which the JGOFS program also focused their efforts on the northern Arabian Sea. This contract involved only the development, calibration and maintenance of the instrumentation. The data processing, other than that which has been necessary for the purposes of quality assurance, was not induded in our original proposal.

  16. A novel acoustic sensor approach to classify seeds based on sound absorption spectra.

    PubMed

    Gasso-Tortajada, Vicent; Ward, Alastair J; Mansur, Hasib; Brøchner, Torben; Sørensen, Claus G; Green, Ole

    2010-01-01

    A non-destructive and novel in situ acoustic sensor approach based on the sound absorption spectra was developed for identifying and classifying different seed types. The absorption coefficient spectra were determined by using the impedance tube measurement method. Subsequently, a multivariate statistical analysis, i.e., principal component analysis (PCA), was performed as a way to generate a classification of the seeds based on the soft independent modelling of class analogy (SIMCA) method. The results show that the sound absorption coefficient spectra of different seed types present characteristic patterns which are highly dependent on seed size and shape. In general, seed particle size and sphericity were inversely related with the absorption coefficient. PCA presented reliable grouping capabilities within the diverse seed types, since the 95% of the total spectral variance was described by the first two principal components. Furthermore, the SIMCA classification model based on the absorption spectra achieved optimal results as 100% of the evaluation samples were correctly classified. This study contains the initial structuring of an innovative method that will present new possibilities in agriculture and industry for classifying and determining physical properties of seeds and other materials. PMID:22163455

  17. Evaluation of MPEG-7-Based Audio Descriptors for Animal Voice Recognition over Wireless Acoustic Sensor Networks.

    PubMed

    Luque, Joaquín; Larios, Diego F; Personal, Enrique; Barbancho, Julio; León, Carlos

    2016-01-01

    Environmental audio monitoring is a huge area of interest for biologists all over the world. This is why some audio monitoring system have been proposed in the literature, which can be classified into two different approaches: acquirement and compression of all audio patterns in order to send them as raw data to a main server; or specific recognition systems based on audio patterns. The first approach presents the drawback of a high amount of information to be stored in a main server. Moreover, this information requires a considerable amount of effort to be analyzed. The second approach has the drawback of its lack of scalability when new patterns need to be detected. To overcome these limitations, this paper proposes an environmental Wireless Acoustic Sensor Network architecture focused on use of generic descriptors based on an MPEG-7 standard. These descriptors demonstrate it to be suitable to be used in the recognition of different patterns, allowing a high scalability. The proposed parameters have been tested to recognize different behaviors of two anuran species that live in Spanish natural parks; the Epidalea calamita and the Alytes obstetricans toads, demonstrating to have a high classification performance. PMID:27213375

  18. Gearbox Tooth Cut Fault Diagnostics Using Acoustic Emission and Vibration Sensors — A Comparative Study

    PubMed Central

    Qu, Yongzhi; He, David; Yoon, Jae; Van Hecke, Brandon; Bechhoefer, Eric; Zhu, Junda

    2014-01-01

    In recent years, acoustic emission (AE) sensors and AE-based techniques have been developed and tested for gearbox fault diagnosis. In general, AE-based techniques require much higher sampling rates than vibration analysis-based techniques for gearbox fault diagnosis. Therefore, it is questionable whether an AE-based technique would give a better or at least the same performance as the vibration analysis-based techniques using the same sampling rate. To answer the question, this paper presents a comparative study for gearbox tooth damage level diagnostics using AE and vibration measurements, the first known attempt to compare the gearbox fault diagnostic performance of AE- and vibration analysis-based approaches using the same sampling rate. Partial tooth cut faults are seeded in a gearbox test rig and experimentally tested in a laboratory. Results have shown that the AE-based approach has the potential to differentiate gear tooth damage levels in comparison with the vibration-based approach. While vibration signals are easily affected by mechanical resonance, the AE signals show more stable performance. PMID:24424467

  19. Detection of third-hand smoke on clothing fibers with a surface acoustic wave gas sensor.

    PubMed

    Cheng, Chi-Yung; Huang, Shih-Shen; Yang, Chia-Min; Tang, Kea-Tiong; Yao, Da-Jeng

    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

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

    PubMed

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

    2016-01-01

    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

  1. A Novel Acoustic Sensor Approach to Classify Seeds Based on Sound Absorption Spectra

    PubMed Central

    Gasso-Tortajada, Vicent; Ward, Alastair J.; Mansur, Hasib; Brøchner, Torben; Sørensen, Claus G.; Green, Ole

    2010-01-01

    A non-destructive and novel in situ acoustic sensor approach based on the sound absorption spectra was developed for identifying and classifying different seed types. The absorption coefficient spectra were determined by using the impedance tube measurement method. Subsequently, a multivariate statistical analysis, i.e., principal component analysis (PCA), was performed as a way to generate a classification of the seeds based on the soft independent modelling of class analogy (SIMCA) method. The results show that the sound absorption coefficient spectra of different seed types present characteristic patterns which are highly dependent on seed size and shape. In general, seed particle size and sphericity were inversely related with the absorption coefficient. PCA presented reliable grouping capabilities within the diverse seed types, since the 95% of the total spectral variance was described by the first two principal components. Furthermore, the SIMCA classification model based on the absorption spectra achieved optimal results as 100% of the evaluation samples were correctly classified. This study contains the initial structuring of an innovative method that will present new possibilities in agriculture and industry for classifying and determining physical properties of seeds and other materials. PMID:22163455

  2. Gearbox tooth cut fault diagnostics using acoustic emission and vibration sensors--a comparative study.

    PubMed

    Qu, Yongzhi; He, David; Yoon, Jae; Van Hecke, Brandon; Bechhoefer, Eric; Zhu, Junda

    2014-01-01

    In recent years, acoustic emission (AE) sensors and AE-based techniques have been developed and tested for gearbox fault diagnosis. In general, AE-based techniques require much higher sampling rates than vibration analysis-based techniques for gearbox fault diagnosis. Therefore, it is questionable whether an AE-based technique would give a better or at least the same performance as the vibration analysis-based techniques using the same sampling rate. To answer the question, this paper presents a comparative study for gearbox tooth damage level diagnostics using AE and vibration measurements, the first known attempt to compare the gearbox fault diagnostic performance of AE- and vibration analysis-based approaches using the same sampling rate. Partial tooth cut faults are seeded in a gearbox test rig and experimentally tested in a laboratory. Results have shown that the AE-based approach has the potential to differentiate gear tooth damage levels in comparison with the vibration-based approach. While vibration signals are easily affected by mechanical resonance, the AE signals show more stable performance. PMID:24424467

  3. Health sensor for human body by using infrared, acoustic energy and magnetic signature

    NASA Astrophysics Data System (ADS)

    Wu, Jerry

    2013-05-01

    There is a general chain of events that applies to infections. Human body infection could causes by many different types of bacteria and virus in different areas or organ systems. In general, doctor can't find out the right solution/treatment for infections unless some certain types of bacteria or virus are detected. These detecting processes, usually, take few days to one week to accomplish. However, some infections of the body may not be able to detect at first round and the patient may lose the timing to receive the proper treatment. In this works, we base on Chi's theory which is an invisible circulation system existed inside the body and propose a novel health sensor which summarizes human's infrared, acoustic energy and magnetic signature and find out, in minutes, the most possible area or organ system that cause the infection just like what Chi-Kung master can accomplish. Therefore, the detection process by doctor will be shortened and it raises the possibility to give the proper treatment to the patient in the earliest timing.

  4. Deciphering acoustic emission signals in drought stressed branches: the missing link between source and sensor

    PubMed Central

    Vergeynst, Lidewei L.; Sause, Markus G. R.; Hamstad, Marvin A.; Steppe, Kathy

    2015-01-01

    When drought occurs in plants, acoustic emission (AE) signals can be detected, but the actual causes of these signals are still unknown. By analyzing the waveforms of the measured signals, it should, however, be possible to trace the characteristics of the AE source and get information about the underlying physiological processes. A problem encountered during this analysis is that the waveform changes significantly from source to sensor and lack of knowledge on wave propagation impedes research progress made in this field. We used finite element modeling and the well-known pencil lead break source to investigate wave propagation in a branch. A cylindrical rod of polyvinyl chloride was first used to identify the theoretical propagation modes. Two wave propagation modes could be distinguished and we used the finite element model to interpret their behavior in terms of source position for both the PVC rod and a wooden rod. Both wave propagation modes were also identified in drying-induced signals from woody branches, and we used the obtained insights to provide recommendations for further AE research in plant science. PMID:26191070

  5. Uncooled infrared sensor technology for hostile fire indication systems

    NASA Astrophysics Data System (ADS)

    Nadav, Shavit; Brodetzki, Guy; Danino, Meir; Zahler, Moti

    2011-06-01

    An evolving combat arena poses an ever-growing hostile fire threat for various ground and airborne targets. Protecting both static posts and moving military platforms against these threats require high performance and affordable solutions, favoring uncooled sensing alert technologies. By analyzing accumulated target and clutter data using new algorithmic and hardware building blocks we establish improved hostile fire indication system configurations. The paper will review new system demonstrations harnessing uncooled IR sensors technology alongside empirical field testing results.

  6. Lidar as a complementary sensor technology for harbor security

    NASA Astrophysics Data System (ADS)

    Steele, Kenneth; Ulich, Bobby; Dietz, Anthony

    2005-05-01

    A comprehensive threat detection system is needed to protect critical assets and infrastructure in the nation's harbors. Such a system must necessarily rely on a variety of sensor technologies to provide protection against airborne, submerged, and surface threats. Although many threats can be detected with current technology, which include sonar, radar, visible light, and infrared sensors, there is a substantive gap in harbor defense against quiet surface intruders such as swimmers. This threat cannot be reliably detected with current sensors. Waves and chop occlude visual detection and render sonar blind to relatively small surface objects. The dark of night is also sufficient to defeat visible light detection methods. Wetsuit materials are available that minimize the infrared signature, matching the surrounding water temperature while cloaking the body's heat. However, a range-gated lidar sensor can be used to detect the signature of the swimmer's shadow, which appears impossible to conceal because it depends only on the opaqueness of the swimmer"s body to visible light. A spatially diffuse laser pulse of short duration is used to illuminate an area of interest. The photons are forward scattered in the water, and effectively illuminate the water to an appreciable depth. By range-gated imaging of the water column beneath the swimmer, the absence of backscattered photons is manifested as a shadow in the sensor image and easily detected with existing image processing algorithms. Lidar technology can therefore close the sensor gap, complementing existing systems and providing greater security coverage. The technology has been successfully demonstrated in the detection of moored and floating sea mines, and is readily scaled to a harbor defense system consisting of a network of imaging lidars.

  7. TECHNOLOGY EVALUATION REPORT, HYDROTECHNICS IN SITU FLOW SENSOR

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) Superfund Innovative Technology Evaluation (SITE) Program evaluated performance of HydroTechnics, Inc. flow sensors in measuring the three-dimensional flow pattern created by operation of the Wasatch Environmental, Inc. (WEI) ground...

  8. TECHNOLOGY EVALUATION REPORT HYDROTECHNICS IN SITU FLOW SENSOR

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) Superfund Innovative Technology Evaluation (SITE) Program evaluated performance of HydroTechnics, Inc. flow sensors in measuring the three-dimensional flow pattern created by operation of the Wasatch Environmental, Inc. (WEI) groundw...

  9. Sensor technology for image-guided surgery

    NASA Astrophysics Data System (ADS)

    Zinreich, S. J.; Helm, Patrick

    1998-06-01

    The advances in radiographic imaging techniques that have occurred within the past decades have significantly enhanced our abilities to display anatomy as well as pathology. Although image acquisition commonly generates three-dimensional datasets, limitation in user interfaces generally requires that this information be presented clinically as a series of two dimensional images. Consequently, during preoperative planning, surgeons are required to mentally transform a wealth of two dimensional hard copy images qualitatively into three-dimensional concepts that are used as a road map to surgery. The sugeron's success is dependent on the accurate mental transfer of Computer Tomographic X-ray (CT) and Magnetic Resonance (MR) imaging information to the operative site to assist direct visual perception of the procedure. Thus, the surgical procedure is performed with the surgeon intuitively transferring radiographic information to the surgical site. Neurosurgeons, for example, are especially hampered because of limited ability to visually distinguish tumor tissue, peritumoral edema, and normal brain parenchyma. This limitation at least partially accounts for the relatively high incidence of subtotal tumor excision. Based on the need to assit the surgeon transform the preoperative scans to the operative site, stereotactic systems were developed and would evolve into frameless stereotaxy with the advance of various sensors.

  10. Biological exposure sensors in coal conversion technologies

    SciTech Connect

    Garrett, A.S. Jr.

    1980-01-01

    When research was begun at ORNL in coal conversion technologies, the Health Division undertook to put together a surveillance package appropriate to the special needs of this group. This report describes the monitoring program instituted to evaluate the health of the population exposed to the chemical constituents of conversion products, effluents, process stream contents or wastes. Particular attention was paid to polycyclic aromatic hydrocarbons (PAH's). (ACR)

  11. Near-field/far-field array manifold of an acoustic vector-sensor near a reflecting boundary.

    PubMed

    Wu, Yue Ivan; Lau, Siu-Kit; Wong, Kainam Thomas

    2016-06-01

    The acoustic vector-sensor (a.k.a. the vector hydrophone) is a practical and versatile sound-measurement device, with applications in-room, open-air, or underwater. It consists of three identical uni-axial velocity-sensors in orthogonal orientations, plus a pressure-sensor-all in spatial collocation. Its far-field array manifold [Nehorai and Paldi (1994). IEEE Trans. Signal Process. 42, 2481-2491; Hawkes and Nehorai (2000). IEEE Trans. Signal Process. 48, 2981-2993] has been introduced into the technical field of signal processing about 2 decades ago, and many direction-finding algorithms have since been developed for this acoustic vector-sensor. The above array manifold is subsequently generalized for outside the far field in Wu, Wong, and Lau [(2010). IEEE Trans. Signal Process. 58, 3946-3951], but only if no reflection-boundary is to lie near the acoustic vector-sensor. As for the near-boundary array manifold for the general case of an emitter in the geometric near field, the far field, or anywhere in between-this paper derives and presents that array manifold in terms of signal-processing mathematics. Also derived here is the corresponding Cramér-Rao bound for azimuth-elevation-distance localization of an incident emitter, with the reflected wave shown to play a critical role on account of its constructive or destructive summation with the line-of-sight wave. The implications on source localization are explored, especially with respect to measurement model mismatch in maximum-likelihood direction finding and with regard to the spatial resolution between coexisting emitters. PMID:27369140

  12. Monolithic integrated system with an electrowetting-on-dielectric actuator and a film-bulk-acoustic-resonator sensor

    NASA Astrophysics Data System (ADS)

    Zhang, Menglun; Cui, Weiwei; Chen, Xuejiao; Wang, Chao; Pang, Wei; Duan, Xuexin; Zhang, Daihua; Zhang, Hao

    2015-02-01

    Although digital microfluidics has shown great potential in a wide range of applications, a lab-on-a-chip with integrated digital droplet actuators and powerful biochemical sensors is still lacking. To address the demand, a fully integrated chip with electrowetting-on-dielectric (EWOD) and a film bulk acoustic resonator (FBAR) sensor is introduced, where an EWOD actuator manipulates digital droplets and the FBAR sensor detects the presence of substances in the droplets, respectively. The piezoelectric layer of the FBAR sensor and the dielectric layer of the EWOD share the same aluminum nitride (AlN) thin film, which is a key factor to achieve the full integration of the two completely different devices. The liquid droplets are reliably managed by the EWOD actuator to sit on or move off the FBAR sensor precisely. Sessile drop experiments and limit of detection (LOD) experiments are carried out to characterize the EWOD actuator and the FBAR sensor, respectively. Taking advantage of the digital droplet operation, a ‘dry sensing mode’ of the FBAR sensor in the lab-on-a-chip microsystem is proposed, which has a much higher signal to noise ratio than the conventional ‘wet sensing mode’. Hg2+ droplets with various concentrations are transported and sensed to demonstrate the capability of the integrated system. The EWOD-FBAR chip is expected to play an important role in many complex lab-on-a-chip applications.

  13. Adaptations of Acoustic Technology for Detection of Hidden Insect Infestations in Trees and Their Root Systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Insects that attack the trunks and roots of trees are difficult to detect and control because the tree structures hide and protect them. The vibrations caused by insects moving and feeding within the root systems can travel over long distances; consequently, acoustic technology is a likely candidat...

  14. Characterization of the HIV-1 TAR RNA-Tat peptide and drug interactions by on-line acoustic wave sensor

    NASA Astrophysics Data System (ADS)

    Tassew, Nardos Gobena

    This thesis presents the application of the thickness shear-mode (TSM) acoustic wave sensor to the study of RNA-protein and RNA-drug interactions at the solid-liquid interface. The binding of the human immunodeficiency virus-type 1 Tat protein to the trans-activation responsive RNA element (TAR) has been studied using this sensor. Data from such measurements show that the sensor is able to discriminate between different Tat peptides derived from the parent protein based on size. The effects of mutations introduced at specific sites in the protein and RNA on the TAR-Tat binding have also been examined in detail. Reduced level of response in acoustic parameters due to mutations was observed indicating that the decrease in binding in response to site specific mutations can be acoustically detected. Data from acoustic wave sensor measurements indicate that the TAR-Tat binding is also affected by ionic strength. Both the frequency and motional resistance signals show periodic responses when varying concentrations of salt are introduced on a TAR-modified surface. The binding of the two molecules seems to be a function of the response of the nucleic acid to salt concentrations. The kinetics of binding of Tat peptides to TAR RNA and to a bulge mutant analogue (MTAR) is also examined from the rate of change of the series resonant frequency. Results from such analysis illustrate longer Tat peptides formed more stable complexes with TAR RNA and exhibited increased discrimination between mutant and wild type TAR. The binding of two aminoglycoside antibiotics, neomycin and streptomycin, to TAR RNA and their effectiveness in preventing TAR-Tat complex formation has been studied in detail. Binding affinity is directly correlated with the inhibitory potency of these molecules and the TSM sensor shows that neomycin exhibits at least a ten fold greater affinity to TAR and that it is also a more potent inhibitor than streptomycin. The results from this research involving TAR-Tat and

  15. OPTICAL FIBER SENSOR TECHNOLOGIES FOR EFFICIENT AND ECONOMICAL OIL RECOVERY

    SciTech Connect

    A. Wang; H. Xiao; R. May

    1999-10-29

    Efficient and complete recovery of petroleum reserves from existing oil wells has proven difficult due to a lack of robust instrumentation that can monitor processes in the downhole environment. Commercially available sensors for measurement of pressure, temperature, and fluid flow exhibit shortened lifetimes in the harsh downhole conditions, which are characterized by high pressures (up to 20 kpsi), temperatures up to 250 C, and exposure to chemically reactive fluids. Development of robust sensors that deliver continuous, real-time data on reservoir performance and petroleum flow pathways will facilitate application of advanced recovery technologies, including horizontal and multi-lateral wells. The main objective of the research program is to develop cost-effective, reliable fiber sensor instrumentation for real-time monitoring and /or control of various key parameters crucial to efficient and economical oil production. This report presents the detailed research work and technical progress from October 1, 1998 to September 30, 1999. The research performed over the first year of the program has followed the schedule as proposed, and solid research progress has been made in specification of the technical requirements, design and fabrication of the SCIIB sensor probes, development of the sensor systems, development of DSP-based signal processing techniques, and construction of the test systems. These technical achievements will significantly help to advance continued research on sensor tests and evaluation during the second year of the program.

  16. Development of Green Box sensor module technologies for rail applications

    SciTech Connect

    Rey, D.; Breeding, R.; Hogan, J.; Mitchell, J.; McKeen, R.G.; Brogan, J.

    1996-04-01

    Results of a joint Sandia National Laboratories, University of New Mexico, and New Mexico Engineering Research Institute project to investigate an architecture implementing real-time monitoring and tracking technologies in the railroad industry is presented. The work, supported by the New Mexico State Transportation Authority, examines a family of smart sensor products that can be tailored to the specific needs of the user. The concept uses a strap-on sensor package, designed as a value-added component, integrated into existing industry systems and standards. Advances in sensor microelectronics and digital signal processing permit us to produce a class of smart sensors that interpret raw data and transmit inferred information. As applied to freight trains, the sensors` primary purpose is to minimize operating costs by decreasing losses due to theft, and by reducing the number, severity, and consequence of hazardous materials incidents. The system would be capable of numerous activities including: monitoring cargo integrity, controlling system braking and vehicle acceleration, recognizing component failure conditions, and logging sensor data. A cost-benefit analysis examines the loss of revenue resulting from theft, hazardous materials incidents, and accidents. Customer survey data are combined with the cost benefit analysis and used to guide the product requirements definition for a series of specific applications. A common electrical architecture is developed to support the product line and permit rapid product realization. Results of a concept validation, which used commercial hardware and was conducted on a revenue-generating train, are also reported.

  17. A comparative evaluation of piezoelectric sensors for acoustic emission-based impact location estimation and damage classification in composite structures

    NASA Astrophysics Data System (ADS)

    Uprety, Bibhisha; Kim, Sungwon; Mathews, V. John; Adams, Daniel O.

    2015-03-01

    Acoustic Emission (AE) based Structural Health Monitoring (SHM) is of great interest for detecting impact damage in composite structures. Within the aerospace industry the need to detect and locate these events, even when no visible damage is present, is important both from the maintenance and design perspectives. In this investigation, four commercially available piezoelectric sensors were evaluated for usage in an AE-based SHM system. Of particular interest was comparing the acoustic response of the candidate piezoelectric sensors for impact location estimations as well as damage classification resulting from the impact in fiber-reinforced composite structures. Sensor assessment was performed based on response signal characterization and performance for active testing at 300 kHz and steel-ball drop testing using both aluminum and carbon/epoxy composite plates. Wave mode velocities calculated from the measured arrival times were found to be in good agreement with predictions obtained using both the Disperse code and finite element analysis. Differences in the relative strength of the received wave modes, the overall signal strengths and signal-to-noise ratios were observed through the use of both active testing as well as passive steel-ball drop testing. Further comparative is focusing on assessing AE sensor performance for use in impact location estimation algorithms as well as detecting and classifying damage produced in composite structures due to impact events.

  18. Quantitative determination of protein molecular weight with an acoustic sensor; significance of specific versus non-specific binding.

    PubMed

    Mitsakakis, Konstantinos; Tsortos, Achilleas; Gizeli, Electra

    2014-08-21

    Surface acoustic wave sensors with integrated microfluidics for multi-sample sensing have been implemented in this work towards the quantitative correlation of the acoustic signal with the molecular weight of surface bound proteins investigating different interaction/binding conditions. The results are presented for: (i) four different biotinylated molecules (30 ≤ Mw ≤ 150 kDa) specifically binding to neutravidin; (ii) the same four non-biotinylated molecules, as well as neutravidin, adsorbing onto gold; and (iii) four cardiac marker proteins (86 ≤ Mw ≤ 540 kDa) specifically binding to their homologous antibodies. Surface plasmon resonance was employed as an independent optical mass sensor. A linear relationship was found to exist between the phase change of the acoustic signal and the molecular weight of the proteins in both cases of specific binding. In contrast, non-specific binding of proteins directly onto gold exhibited no such linear relationship. In all three cases phase change was correlated with the bound mass per area. The underlying mechanism behind the different behavior between specific and non-specific binding is discussed by taking into account the geometrical restrictions imposed by the size of the specific biorecognition molecule and the corresponding bound protein. Our results emphasize the quantitative nature of the phase of the acoustic signal in determining the Mw (in the case of specific binding) with a resolution of 15% and the mass of the bound proteins (in all cases), as well as the significance of the biorecognition molecules in deriving the molecular weight from acoustic or optical detectors. PMID:24943453

  19. EHD as sensor fabrication technology for robotic skins

    NASA Astrophysics Data System (ADS)

    Shin, Jeongsik; Lee, Woo Ho; Nothnagle, Caleb; Wijesundara, Muthu B. J.

    2014-06-01

    Human-robot interaction can be made more sophisticated and intuitive if the entire body of a robot is covered with multimodal sensors embedded in artificial skin. In order to efficiently interact with humans in unstructured environments, robotic skin may require sensors such as touch, impact, and proximity. Integration of various types of sensors into robotic skin is challenging due to the topographical nature of skin. Printing is a promising technology that can be explored for sensor integration as it may allow both sensors and interconnects to be directly printed into the skin. We are developing Electrohydrodynamic (EHD) inkjet printing technology in order to co-fabricate various devices onto a single substrate. Using strong applied electrostatic forces, EHD allows the printing of microscale features from a wide array of materials with viscosities ranging from 100 to 1000cP, highly beneficial for multilateral integration. Thus far we have demonstrated EHD's capability at printing patterns of Poly(2,3-dihydrothieno-1,4-dioxin)-poly(styrenesulfonate) for pressure sensor applications, generating patterns with modified commercial photoresist for mask-less lithography, and obtaining ZnO microstructures for direct device printing. Printed geometries range from a few tens of microns to millimeters. We have used inks with viscosities ranging from 230 to 520cp and from non-conductive to 135μS/cm. These results clearly show that the EHD is a promising multi-material printing platform and would be an enabling technology that can be used to co-fabricate various devices into robotic skin.

  20. 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

    2015-08-01

    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

  1. Using Big Data Technologies and Analytics to Predict Sensor Anomalies

    NASA Astrophysics Data System (ADS)

    Mital, R.; Coughlin, J.; Canaday, M.

    A goal of big data analytics is to help leaders make informed and rapid decisions by analyzing large volumes of complex data, as well as other forms of data that may be untapped by conventional analyses, and presenting it in a form that facilitates decision making. Big data analytics is the process of examining large data sets containing a variety of data types to uncover hidden patterns, unknown correlations, and other useful information. Sensors typically record significant amounts of data but it is often not exploited except in special cases and after historically large amounts of analysis time. Big data analytics provides a mechanism to routinely monitor these data sets while also providing insight into anomalous events, such as are encountered in large sensor systems such as those in the space surveillance network. In this study, we simulate recorded data from a notional radar or optical sensor and use big data technologies and the analytics to process the data to analyze and predict sensor performance. This study focuses on data products that would commonly be analyzed at a site and how big data technologies can be used to detect anomalies. This study shows how the ability to rapidly drill down into the data enables an analyst or decision maker to assess potential system anomalies. This study shows how current technologies and predictive analytical techniques can be used to view the data, detect and explain anomalies, and predict preventative maintenance actions in a timely manner.

  2. Security applications of a remote electric-field sensor technology

    NASA Astrophysics Data System (ADS)

    Prance, Robert J.; Harland, Christopher J.; Prance, Helen

    2008-10-01

    A new generation of electric field sensors developed at the University of Sussex is enabling an alternative to contact voltage and non-contact magnetic field measurements. We have demonstrated the capability of this technology in a number of areas including ECG through clothing, remote off-body ECG, through wall movement sensing and electric field imaging. Clearly, there are many applications for a generic sensor technology with this capability, including long term vital sign monitoring. The non-invasive nature of the measurement also makes these sensors ideal for man/machine and human/robot interfacing. In addition, there are obvious security and biometric possibilities since we can obtain physiological data remotely, without the knowledge of the subject. This is a clear advantage if such systems are to be used for evaluating the psychological state of a subject. In this paper we report the results obtained with a new version of the sensor which is capable of acquiring electrophysiological signals remotely in an open unshielded laboratory. We believe that this technology opens up a new area of remote biometrics which could have considerable implications for security applications. We have also demonstrated the ability of EPS to function in closely-packed one and two dimensional arrays for real-time imaging.

  3. Wireless sensor technology for in-situ plasma process monitoring

    NASA Astrophysics Data System (ADS)

    Gahan, David

    2015-09-01

    There is an increasing demand for plasma measurement and control solutions to cope with the growing complexity of integrated circuit manufacture in the semiconductor industry. Standard plasma diagnostic instruments used in research, such as the Langmuir probe, are not suitable for use in the production environment for myriad reasons - contamination of the process being one of the main concerns. Silicon wafer based wireless sensors, which measure temperature during the process, have gained the most traction with tool manufacturers and chip makers - albeit during process development or the PM cycle rather than live production. In this presentation we will discuss two novel wireless technologies that have the potential for use in process tools. The first is an ion detector embedded in a silicon wafer. The sensor measures the average ion flux and the maximum ion energy during the process. This information is stored and is downloaded later for analysis. The second technology consists of a wireless sensor that sits inside the process and communicates data in real time to a detector installed on the rf power line. This platform is similar to RFID technology and can be combined with various sensor types to transmit data to the user during the process.

  4. Technology Demonstration: Acoustic Condition Assessment of Wastewater Collection Systems

    EPA Science Inventory

    The overall objective of this EPA-funded study was to demonstrate innovative sewer line assessment technologies that are designed for rapid deployment using portable equipment. This study focused on demonstration of technologies that are suitable for smaller diameter pipes (less ...

  5. Further Structural Intelligence for Sensors Cluster Technology in Manufacturing

    PubMed Central

    Mekid, Samir

    2006-01-01

    With the ever increasing complex sensing and actuating tasks in manufacturing plants, intelligent sensors cluster in hybrid networks becomes a rapidly expanding area. They play a dominant role in many fields from macro and micro scale. Global object control and the ability to self organize into fault-tolerant and scalable systems are expected for high level applications. In this paper, new structural concepts of intelligent sensors and networks with new intelligent agents are presented. Embedding new functionalities to dynamically manage cooperative agents for autonomous machines are interesting key enabling technologies most required in manufacturing for zero defects production.

  6. 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.

  7. Cutting Edge Technologies Presentation: An Overview of Developing Sensor Technology Directions and Possible Barriers to New Technology Implementation

    NASA Technical Reports Server (NTRS)

    Hunter, Gary W.

    2007-01-01

    The aerospace industry requires the development of a range of chemical sensor technologies for such applications as leak detection, emission monitoring, fuel leak detection, environmental monitoring, and fire detection. A range of chemical sensors are being developed based on micromachining and microfabrication technology to fabricate microsensors with minimal size, weight, and power consumption; and the use of nanomaterials and structures to develop sensors with improved stability combined with higher sensitivity, However, individual sensors are limited in the amount of information that they can provide in environments that contain multiple chemical species. Thus, sensor arrays are being developed to address detection needs in such multi-species environments. These technologies and technical approaches have direct relevance to breath monitoring for clinical applications. This presentation gives an overview of developing cutting-edge sensor technology and possible barriers to new technology implementation. This includes lessons learned from previous microsensor development, recent work in development of a breath monitoring system, and future directions in the implementation of cutting edge sensor technology.

  8. Breakthrough Sensor Technology for Space Exploration in the 21st Century

    NASA Technical Reports Server (NTRS)

    Krabach, T.

    2000-01-01

    The Breakthrough Sensors and Instrument Component Technology (BSICT) thrust area fosters the develop of breakthrough technology in the areas of detectors, sensors, lasers, coolers and electronics to enable a new set of exciting NASA missions in the new millennium.

  9. Evaluating the adhesion of SU-8 thin films using an AlN/Si surface acoustic wave sensor

    NASA Astrophysics Data System (ADS)

    El Gowini, Mohamed M.; Moussa, Walied A.

    2015-03-01

    A new approach is developed for evaluating the adhesion of SU-8 thin films using a surface acoustic wave (SAW) sensor. The SAW sensor consists of a silicon (Si) substrate coated with a thin aluminum nitride (AlN) film and two sets of inter-digital electrodes (IDT) patterned on the AlN surface. Two sensor configurations are developed in order to evaluate the adhesion of SU-8. In the first configuration the SU-8 layer is patterned on top of a gold film that is deposited on the AlN surface. In the second configuration the gold film is coated with an omnicoat layer prior to patterning the SU-8 film. Omnicoat is an adhesion promoter for SU-8, which is used to increase its adhesion to gold. The frequency responses from both configurations are measured and the shift in the center frequency value is evaluated. The results illustrate that without omnicoat the center frequency shifts to a higher value indicating an increase in the wave velocity. This is because the poor adhesion of the SU-8 layer without omnicoat causes the wave to be more concentrated in the AlN/Si structure and AlN has a higher acoustic wave velocity in comparison to the SU-8 layer. In addition, four SAW sensors operating at four different center frequencies are developed to investigate the change in sensor sensitivity with the increase in center frequency. The results indicate that the sensor sensitivity increases proportionally to the increase in operating frequency. Finally, a theoretical model is developed to calculate the wave dispersion profile for the SU-8/AlN/Si configuration. The interface of the SU-8/AlN layers is modeled as a layer of mass-less springs with stiffness K(N m-3). The shifts in the wave dispersion profile at different levels of interface spring stiffness are compared to the experimental values to evaluate the adhesion of the SU-8 layer.

  10. Near-infrared fluorescence sensor technology

    NASA Astrophysics Data System (ADS)

    Evans, Lawrence, III; Casay, Guillermo A.; Dai, Dong; Patonay, Gabor

    1995-10-01

    Fluorescence spectroscopy has been used extensively to solve environmental problems (including biological, water quality, separation and etc.). Despite its numerous applications, long wavelength, near- infrared (NIR) fluorescence has been the subject of very few studies. This wavelength region is advantageous, if we wish to minimize the effect of background interference. Lowering the background interference is especially advantageous in environmental monitoring applications where very little or no preseparation is necessary to achieve selective measurements. The applications of NIR absorbing fluorophores which usually have high molar absorptivities and good quantum yields can be especially advantageous when laser diodes are employed as the excitation source. This paper will focus on several general practical analytical applications of NIR fluorescence spectroscopy for solving environmental related analytical problems, including but not limited to: use of NIR fluorophores as labels (in conjunction with immunosensor technology) and the use of NIR chromophores as direct probes (pH, metal ion, etc.). Additionally the use of laser diodes and semiconductor detectors (silicon photodiodes and avalanche photodiodes) as light sources and detectors will be discussed.

  11. Near-infrared fluorescence sensor technology

    SciTech Connect

    Evans, L. III; Casay, G.A.; Dai, D.; Patonay, G.

    1995-12-31

    Fluorescence spectroscopy has been used extensively to solve environmental problems (including biological, water quality, separation and etc.). Despite its numerous applications, long wavelength, near-infrared (NIR) fluorescence has been the subject of very few studies. This wavelength region is advantageous, if there is a need to minimize the effect of background interference. Lowering the background interference is especially advantageous in environmental monitoring applications where very little or no preparation is necessary to achieve selective measurements. The application of NIR absorbing fluorophores which usually have high molar absorptivities and good quantum yields can be especially advantageous when laser diodes are employed as the excitation source. This paper will focus on several general practical but not limited to: use of NIR fluorophores as labels (in conjunction with immunosensor technology) and the use of NIR chromophores as direct probes (pH, metal ions, etc.). Additionally the use of laser diodes and semiconductor detectors (silicon photodiodes and avalanche photodiodes) as light sources and detectors will be discussed.

  12. A Wide Range Temperature Sensor Using SOI Technology

    NASA Technical Reports Server (NTRS)

    Patterson, Richard L.; Elbuluk, Malik E.; Hammoud, Ahmad

    2009-01-01

    Silicon-on-insulator (SOI) technology is becoming widely used in integrated circuit chips for its advantages over the conventional silicon counterpart. The decrease in leakage current combined with lower power consumption allows electronics to operate in a broader temperature range. This paper describes the performance of an SOIbased temperature sensor under extreme temperatures and thermal cycling. The sensor comprised of a temperature-to-frequency relaxation oscillator circuit utilizing an SOI precision timer chip. The circuit was evaluated under extreme temperature exposure and thermal cycling between -190 C and +210 C. The results indicate that the sensor performed well over the entire test temperature range and it was able to re-start at extreme temperatures.

  13. New Sensor Technologies for Ocean Exploration and Observation

    NASA Astrophysics Data System (ADS)

    Manley, J. E.

    2005-12-01

    NOAA's Office of Ocean Exploration (OE) is an active supporter of new ocean technologies. Sensors, in particular, have been a focus of recent investments as have platforms that can support both dedicated voyages of discovery and Integrated Ocean Observing Systems (IOOS). Recent programs sponsored by OE have developed technical solutions that will be of use in sensor networks and in stand-alone ocean research programs. Particular projects include: 1) the Joint Environmental Science Initiative (JESI) a deployment of a highly flexible marine sensing system, in collaboration with NASA, that demonstrated a new paradigm for marine ecosystem monitoring. 2) the development and testing of an in situ marine mass spectrometer, via grant to the Woods Hole Oceanographic Institution (WHOI). This instrument has been designed to function at depths up to 5000 meters. 3) the evolution of glider AUVs for aerial deployment, through a grant to Webb Research Corporation. This program's goal is air certification for gliders, which will allow them to be operationally deployed from NAVOCEANO aircraft. 4) the development of new behaviors for the Autonomous Benthic Explorer (ABE) allowing it to anchor in place and await instructions, through a grant to WHOI. This will support the operational use of AUVs in observing system networks. 5) development of new sensors for AUVs through a National Ocean Partnership Program (NOPP) award to Rutgers Universty. This project will develop a Fluorescence Induction Relaxation (FIRe) System to measure biomass and integrate the instrument into an AUV glider. 6) an SBIR award for the development of anti-fouling technologies for solar panels and in situ sensors. This effort at Nanohmics Inc. is developing natural product antifoulants (NPA) in optical quality hard polymers. The technology and results of each of these projects are one component of OE's overall approach to technology research and development. OE's technology program represents the leading edge of

  14. Monitoring Anthropogenic Ocean Sound from Shipping Using an Acoustic Sensor Network and a Compressive Sensing Approach †

    PubMed Central

    Harris, Peter; Philip, Rachel; Robinson, Stephen; Wang, Lian

    2016-01-01

    Monitoring ocean acoustic noise has been the subject of considerable recent study, motivated by the desire to assess the impact of anthropogenic noise on marine life. A combination of measuring ocean sound using an acoustic sensor network and modelling sources of sound and sound propagation has been proposed as an approach to estimating the acoustic noise map within a region of interest. However, strategies for developing a monitoring network are not well established. In this paper, considerations for designing a network are investigated using a simulated scenario based on the measurement of sound from ships in a shipping lane. Using models for the sources of the sound and for sound propagation, a noise map is calculated and measurements of the noise map by a sensor network within the region of interest are simulated. A compressive sensing algorithm, which exploits the sparsity of the representation of the noise map in terms of the sources, is used to estimate the locations and levels of the sources and thence the entire noise map within the region of interest. It is shown that although the spatial resolution to which the sound sources can be identified is generally limited, estimates of aggregated measures of the noise map can be obtained that are more reliable compared with those provided by other approaches. PMID:27011187

  15. Improved Maturity and Ripeness Classifications of Magnifera Indica cv. Harumanis Mangoes through Sensor Fusion of an Electronic Nose and Acoustic Sensor

    PubMed Central

    Zakaria, Ammar; Shakaff, Ali Yeon Md; Masnan, Maz Jamilah; Saad, Fathinul Syahir Ahmad; Adom, Abdul Hamid; Ahmad, Mohd Noor; Jaafar, Mahmad Nor; Abdullah, Abu Hassan; Kamarudin, Latifah Munirah

    2012-01-01

    In recent years, there have been a number of reported studies on the use of non-destructive techniques to evaluate and determine mango maturity and ripeness levels. However, most of these reported works were conducted using single-modality sensing systems, either using an electronic nose, acoustics or other non-destructive measurements. This paper presents the work on the classification of mangoes (Magnifera Indica cv. Harumanis) maturity and ripeness levels using fusion of the data of an electronic nose and an acoustic sensor. Three groups of samples each from two different harvesting times (week 7 and week 8) were evaluated by the e-nose and then followed by the acoustic sensor. Principal Component Analysis (PCA) and Linear Discriminant Analysis (LDA) were able to discriminate the mango harvested at week 7 and week 8 based solely on the aroma and volatile gases released from the mangoes. However, when six different groups of different maturity and ripeness levels were combined in one classification analysis, both PCA and LDA were unable to discriminate the age difference of the Harumanis mangoes. Instead of six different groups, only four were observed using the LDA, while PCA showed only two distinct groups. By applying a low level data fusion technique on the e-nose and acoustic data, the classification for maturity and ripeness levels using LDA was improved. However, no significant improvement was observed using PCA with data fusion technique. Further work using a hybrid LDA-Competitive Learning Neural Network was performed to validate the fusion technique and classify the samples. It was found that the LDA-CLNN was also improved significantly when data fusion was applied. PMID:22778629

  16. First tests of CHERWELL, a Monolithic Active Pixel Sensor: A CMOS Image Sensor (CIS) using 180 nm technology

    NASA Astrophysics Data System (ADS)

    Mylroie-Smith, James; Kolya, Scott; Velthuis, Jaap; Bevan, Adrian; Inguglia, Gianluca; Headspith, Jon; Lazarus, Ian; Lemon, Roy; Crooks, Jamie; Turchetta, Renato; Wilson, Fergus

    2013-12-01

    The Cherwell is a 4T CMOS sensor in 180 nm technology developed for the detection of charged particles. Here, the different test structures on the sensor will be described and first results from tests on the reference pixel variant are shown. The sensors were shown to have a noise of 12 e- and a signal to noise up to 150 in 55Fe.

  17. Design and implementation of low complexity wake-up receiver for underwater acoustic sensor networks

    NASA Astrophysics Data System (ADS)

    Yue, Ming

    This thesis designs a low-complexity dual Pseudorandom Noise (PN) scheme for identity (ID) detection and coarse frame synchronization. The two PN sequences for a node are identical and are separated by a specified length of gap which serves as the ID of different sensor nodes. The dual PN sequences are short in length but are capable of combating severe underwater acoustic (UWA) multipath fading channels that exhibit time varying impulse responses up to 100 taps. The receiver ID detection is implemented on a microcontroller MSP430F5529 by calculating the correlation between the two segments of the PN sequence with the specified separation gap. When the gap length is matched, the correlator outputs a peak which triggers the wake-up enable. The time index of the correlator peak is used as the coarse synchronization of the data frame. The correlator is implemented by an iterative algorithm that uses only one multiplication and two additions for each sample input regardless of the length of the PN sequence, thus achieving low computational complexity. The real-time processing requirement is also met via direct memory access (DMA) and two circular buffers to accelerate data transfer between the peripherals and the memory. The proposed dual PN detection scheme has been successfully tested by simulated fading channels and real-world measured channels. The results show that, in long multipath channels with more than 60 taps, the proposed scheme achieves high detection rate and low false alarm rate using maximal-length sequences as short as 31 bits to 127 bits, therefore it is suitable as a low-power wake-up receiver. The future research will integrate the wake-up receiver with Digital Signal Processors (DSP) for payload detection.

  18. The acoustic results of a United Technologies scale model helicopter rotor tested at DNW

    NASA Technical Reports Server (NTRS)

    Liu, Sandy R.; Marcolini, Michael A.

    1990-01-01

    In a major cooperative program between U.S. Government agencies (represented by the U.S. Army Aeroflightdynamics Directorate and NASA Ames and Langley Research Centers) and United Technologies Corp., a 1/6 geometrically and aeroelastically scaled UTC model helicopter rotor was tested in the open-jet anechoic test section of the Duits-Nederlandse Windtunnel in the Netherlands. As the fourth entry under the Aerodynamic and Acoustic Testing of Model Rotors Program, several comprehensive acoustic and aerodynamic databases were obtained relating the important aerodynamic phenomena to both the near- and far-field acoustic radiation. In particular, high speed impulsive noise and blade-vortex interaction are of primary interest. This paper provides an initial summary of the acoustic measurements acquired for some of the different configurations tested. A review of the baseline swept tip rotor acoustic characteristics in the regimes of high speed forward flight, where high speed impulsive noise dominates, and low speed descent, where severe blade vortex interaction noise occurs, is presented. The trends of these primary noise sources are studied as the first step in validating the data for release and application.

  19. Underwater Wireless Sensor Networks: How Do Acoustic Propagation Models Impact the Performance of Higher-Level Protocols?

    PubMed Central

    Llor, Jesús; Malumbres, Manuel P.

    2012-01-01

    Several Medium Access Control (MAC) and routing protocols have been developed in the last years for Underwater Wireless Sensor Networks (UWSNs). One of the main difficulties to compare and validate the performance of different proposals is the lack of a common standard to model the acoustic propagation in the underwater environment. In this paper we analyze the evolution of underwater acoustic prediction models from a simple approach to more detailed and accurate models. Then, different high layer network protocols are tested with different acoustic propagation models in order to determine the influence of environmental parameters on the obtained results. After several experiments, we can conclude that higher-level protocols are sensitive to both: (a) physical layer parameters related to the network scenario and (b) the acoustic propagation model. Conditions like ocean surface activity, scenario location, bathymetry or floor sediment composition, may change the signal propagation behavior. So, when designing network architectures for UWSNs, the role of the physical layer should be seriously taken into account in order to assert that the obtained simulation results will be close to the ones obtained in real network scenarios. PMID:22438712

  20. Underwater Wireless Sensor Networks: how do acoustic propagation models impact the performance of higher-level protocols?

    PubMed

    Llor, Jesús; Malumbres, Manuel P

    2012-01-01

    Several Medium Access Control (MAC) and routing protocols have been developed in the last years for Underwater Wireless Sensor Networks (UWSNs). One of the main difficulties to compare and validate the performance of different proposals is the lack of a common standard to model the acoustic propagation in the underwater environment. In this paper we analyze the evolution of underwater acoustic prediction models from a simple approach to more detailed and accurate models. Then, different high layer network protocols are tested with different acoustic propagation models in order to determine the influence of environmental parameters on the obtained results. After several experiments, we can conclude that higher-level protocols are sensitive to both: (a) physical layer parameters related to the network scenario and (b) the acoustic propagation model. Conditions like ocean surface activity, scenario location, bathymetry or floor sediment composition, may change the signal propagation behavior. So, when designing network architectures for UWSNs, the role of the physical layer should be seriously taken into account in order to assert that the obtained simulation results will be close to the ones obtained in real network scenarios. PMID:22438712

  1. Packaging Technologies for High Temperature Electronics and Sensors

    NASA Technical Reports Server (NTRS)

    Chen, Liang-Yu; Hunter, Gary W.; Neudeck, Philip G.; Beheim, Glenn M.; Spry, David J.; Meredith, Roger D.

    2013-01-01

    This paper reviews ceramic substrates and thick-film metallization based packaging technologies in development for 500 C silicon carbide (SiC) electronics and sensors. Prototype high temperature ceramic chip-level packages and printed circuit boards (PCBs) based on ceramic substrates of aluminum oxide (Al2O3) and aluminum nitride (AlN) have been designed and fabricated. These ceramic substrate-based chip-level packages with gold (Au) thick-film metallization have been electrically characterized at temperatures up to 550 C. A 96% alumina based edge connector for a PCB level subsystem interconnection has also been demonstrated recently. The 96% alumina packaging system composed of chip-level packages and PCBs has been tested with high temperature SiC devices at 500 C for over 10,000 hours. In addition to tests in a laboratory environment, a SiC JFET with a packaging system composed of a 96% alumina chip-level package and an alumina printed circuit board mounted on a data acquisition circuit board was launched as a part of the MISSE-7 suite to the International Space Station via a Shuttle mission. This packaged SiC transistor was successfully tested in orbit for eighteen months. A spark-plug type sensor package designed for high temperature SiC capacitive pressure sensors was developed. This sensor package combines the high temperature interconnection system with a commercial high temperature high pressure stainless steel seal gland (electrical feed-through). Test results of a packaged high temperature capacitive pressure sensor at 500 C are also discussed. In addition to the pressure sensor package, efforts for packaging high temperature SiC diode-based gas chemical sensors are in process.

  2. Packaging Technologies for High Temperature Electronics and Sensors

    NASA Technical Reports Server (NTRS)

    Chen, Liangyu; Hunter, Gary W.; Neudeck, Philip G.; Beheim, Glenn M.; Spry, David J.; Meredith, Roger D.

    2013-01-01

    This paper reviews ceramic substrates and thick-film metallization based packaging technologies in development for 500degC silicon carbide (SiC) electronics and sensors. Prototype high temperature ceramic chip-level packages and printed circuit boards (PCBs) based on ceramic substrates of aluminum oxide (Al2O3) and aluminum nitride (AlN) have been designed and fabricated. These ceramic substrate-based chiplevel packages with gold (Au) thick-film metallization have been electrically characterized at temperatures up to 550degC. A 96% alumina based edge connector for a PCB level subsystem interconnection has also been demonstrated recently. The 96% alumina packaging system composed of chip-level packages and PCBs has been tested with high temperature SiC devices at 500degC for over 10,000 hours. In addition to tests in a laboratory environment, a SiC JFET with a packaging system composed of a 96% alumina chip-level package and an alumina printed circuit board mounted on a data acquisition circuit board was launched as a part of the MISSE-7 suite to the International Space Station via a Shuttle mission. This packaged SiC transistor was successfully tested in orbit for eighteen months. A spark-plug type sensor package designed for high temperature SiC capacitive pressure sensors was developed. This sensor package combines the high temperature interconnection system with a commercial high temperature high pressure stainless steel seal gland (electrical feed-through). Test results of a packaged high temperature capacitive pressure sensor at 500degC are also discussed. In addition to the pressure sensor package, efforts for packaging high temperature SiC diode-based gas chemical sensors are in process.

  3. Advances in Thin Film Sensor Technologies for Engine Applications

    NASA Technical Reports Server (NTRS)

    Lei, Jih-Fen; Martin, Lisa C.; Will, Herbert A.

    1997-01-01

    Advanced thin film sensor techniques that can provide accurate surface strain and temperature measurements are being developed at NASA Lewis Research Center. These sensors are needed to provide minimally intrusive characterization of advanced materials (such as ceramics and composites) and structures (such as components for Space Shuttle Main Engine, High Speed Civil Transport, Advanced Subsonic Transports and General Aviation Aircraft) in hostile, high-temperature environments and for validation of design codes. This paper presents two advanced thin film sensor technologies: strain gauges and thermocouples. These sensors are sputter deposited directly onto the test articles and are only a few micrometers thick; the surface of the test article is not structurally altered and there is minimal disturbance of the gas flow over the surface. The strain gauges are palladium-13% chromium based and the thermocouples are platinum-13% rhodium vs. platinum. The fabrication techniques of these thin film sensors in a class 1000 cleanroom at the NASA Lewis Research Center are described. Their demonstration on a variety of engine materials, including superalloys, ceramics and advanced ceramic matrix composites, in several hostile, high-temperature test environments are discussed.

  4. Introduction to the Special Issue on "State-of-the-Art Sensor Technology in Japan 2015".

    PubMed

    Tokumitsu, Masahiro; Ishida, Yoshiteru

    2016-01-01

    This Special Issue, "State-of-the-Art Sensor Technology in Japan 2015", collected papers on different kinds of sensing technology: fundamental technology for intelligent sensors, information processing for monitoring humans, and information processing for adaptive and survivable sensor systems.[...]. PMID:27563895

  5. The achievements and future prospects of Chinese space optical remote sensor technology

    NASA Astrophysics Data System (ADS)

    Zhou, Feng; Liu, Zhaojun

    2011-08-01

    The launched space optical Remote Sensors, including the three generations of space film remote sensor, the space CCD remote sensor and the IRMSS for resources survey, the first generation CCD and IR remote sensor for disaster monitoring, the first generation CCD and IR camera for ocean monitoring, the related remote sensor in polar orbit and geostationary orbit for meteorological detection and forecasting, the first generation related remote sensor for deep space exploration, etc, are presented in detail in the paper. The related technologies, including system design technology, the lens technology, the FPA video technology, the manufacture technology, the AIT technology, etc, are also introduced in the paper. The Chinese great achievements in the field of space optical remote sensor are shown. The prospects on future development of the space serial optical remote sensors and the related technologies are made.

  6. Wind shear detection. Forward-looking sensor technology

    NASA Technical Reports Server (NTRS)

    Bracalente, E. M. (Compiler); Delnore, V. E. (Compiler)

    1987-01-01

    A meeting took place at NASA Langley Research Center in February 1987 to discuss the development and eventual use of forward-looking remote sensors for the detection and avoidance of wind shear by aircraft. The participants represented industry, academia, and government. The meeting was structured to provide first a review of the current FAA and NASA wind shear programs, then to define what really happens to the airplane, and finally to give technology updates on the various types of forward-looking sensors. This document is intended to informally record the essence of the technology updates (represented here through unedited duplication of the vugraphs used), and the floor discussion following each presentation. Also given are key issues remaining unresolved.

  7. Wireless intelligent alarm technology with pyroelectric infrared sensor

    NASA Astrophysics Data System (ADS)

    Chen, Xiao

    2009-07-01

    Aiming at the defects of monitoring conducted by man in the conventional practice, we study the passive intelligent automatic alarm technology based on the pyroelectric infrared sensor and wireless communication technology. The designed passive infrared wireless alarm is composed of pyroelectric infrared sensors, infrared special chip BISS0001 and their peripheral circuits. When someone enters into the detecting and monitoring range, the alarm will detect the infrared ray of the human radiation by the contactless form and detect the signals of circuit output. Then it translates them into low frequency signals relative with human sports speed, distance and direction, produce corresponding output signals through amplifying by the back state controller, switch on the work power of the wireless transmitting circuit and make it emit the alarm signals. The system enhances the monitoring level and effects and possesses many advantages such as wide detecting range, long detecting distance and high reliability.

  8. Design, fabrication, and optimization of photo acoustic gas sensor for the trace level detection of NO2 in the atmosphere.

    PubMed

    Gondal, Mohammed A; Dastageer, Mohamed A

    2010-09-01

    Photoacoustic (PA) gas sensor for the detection of hazardous NO(2) with detection limit as low as few part per billion by volume (ppbV) has been designed and tested with pulsed UV laser. Some design optimization factors such as the optimum cell geometry, buffer gas etc has been proposed. It was found that a cylindrical cell with many acoustic filters considerably dampens the noise level and also argon as a buffer gas improves the photoacoustic signal level and this combination substantially improved the signal to noise ratio and the limit of detection. Ambiguous decline of photo acoustic signal at higher NO(2) concentration due to the adsorption of NO(2) on the walls of the photoacoustic cells and the dependence of this effect on the buffer gases are also discussed. The PA signal dependence on incident laser energy for three cells was also investigated. PMID:20665325

  9. Acoustic emission detection of macro-cracks on engraving tool steel inserts during the injection molding cycle using PZT sensors.

    PubMed

    Svečko, Rajko; Kusić, Dragan; Kek, Tomaž; Sarjaš, Andrej; Hančič, Aleš; Grum, Janez

    2013-01-01

    This paper presents an improved monitoring system for the failure detection of engraving tool steel inserts during the injection molding cycle. This system uses acoustic emission PZT sensors mounted through acoustic waveguides on the engraving insert. We were thus able to clearly distinguish the defect through measured AE signals. Two engraving tool steel inserts were tested during the production of standard test specimens, each under the same processing conditions. By closely comparing the captured AE signals on both engraving inserts during the filling and packing stages, we were able to detect the presence of macro-cracks on one engraving insert. Gabor wavelet analysis was used for closer examination of the captured AE signals' peak amplitudes during the filling and packing stages. The obtained results revealed that such a system could be used successfully as an improved tool for monitoring the integrity of an injection molding process. PMID:23673677

  10. An Ultra-Low Power and Flexible Acoustic Modem Design to Develop Energy-Efficient Underwater Sensor Networks

    PubMed Central

    Sánchez, Antonio; Blanc, Sara; Yuste, Pedro; Perles, Angel; Serrano, Juan José

    2012-01-01

    This paper is focused on the description of the physical layer of a new acoustic modem called ITACA. The modem architecture includes as a major novelty an ultra-low power asynchronous wake-up system implementation for underwater acoustic transmission that is based on a low-cost off-the-shelf RFID peripheral integrated circuit. This feature enables a reduced power dissipation of 10 μW in stand-by mode and registers very low power values during reception and transmission. The modem also incorporates clear channel assessment (CCA) to support CSMA-based medium access control (MAC) layer protocols. The design is part of a compact platform for a long-life short/medium range underwater wireless sensor network. PMID:22969324

  11. Acoustic Emission Detection of Macro-Cracks on Engraving Tool Steel Inserts during the Injection Molding Cycle Using PZT Sensors

    PubMed Central

    Svečko, Rajko; Kusić, Dragan; Kek, Tomaž; Sarjaš, Andrej; Hančič, Aleš; Grum, Janez

    2013-01-01

    This paper presents an improved monitoring system for the failure detection of engraving tool steel inserts during the injection molding cycle. This system uses acoustic emission PZT sensors mounted through acoustic waveguides on the engraving insert. We were thus able to clearly distinguish the defect through measured AE signals. Two engraving tool steel inserts were tested during the production of standard test specimens, each under the same processing conditions. By closely comparing the captured AE signals on both engraving inserts during the filling and packing stages, we were able to detect the presence of macro-cracks on one engraving insert. Gabor wavelet analysis was used for closer examination of the captured AE signals' peak amplitudes during the filling and packing stages. The obtained results revealed that such a system could be used successfully as an improved tool for monitoring the integrity of an injection molding process. PMID:23673677

  12. Technology Demonstration: Acoustic Condition Assessment of Wastewater Collection Systems

    EPA Science Inventory

    The overall objective of this demonstration project was to evaluate technologies that are designed for rapid deployment using portable equipment that can result in significant cost-savings to wastewater utilities. Smaller diameter pipes (i.e., less than 12-inch diameter) are gen...

  13. Liquid density analysis of sucrose and alcoholic beverages using polyimide guided Love-mode acoustic wave sensors

    NASA Astrophysics Data System (ADS)

    Turton, Andrew; Bhattacharyya, Debabrata; Wood, David

    2006-02-01

    A liquid density sensor using Love-mode acoustic waves has been developed which is suitable for use in the food and drinks industries. The sensor has an open flat surface allowing immersion into a sample and simple cleaning. A polyimide waveguide layer allows cheap and simple fabrication combined with a robust chemically resistant surface. The low shear modulus of polyimide allows thin guiding layers giving a high sensitivity. A dual structure with a smooth reference device exhibiting viscous coupling with the wave, and a patterned sense area to trap the liquid causing mass loading, allows discrimination of the liquid density from the square root of the density-viscosity product (ρη)0.5. Frequency shift and insertion loss change were proportional to (ρη)0.5 with a non-linear response due to the non-Newtonian nature of viscous liquids at high frequencies. Measurements were made with sucrose solutions up to 50% and different alcoholic drinks. A maximum sensitivity of 0.13 µg cm-3 Hz-1 was achieved, with a linear frequency response to density. This is the highest liquid density sensitivity obtained for acoustic mode sensors to the best of our knowledge.

  14. An intelligent sensor array distributed system for vibration analysis and acoustic noise characterization of a linear switched reluctance actuator.

    PubMed

    Salvado, José; Espírito-Santo, António; Calado, Maria

    2012-01-01

    This paper proposes a distributed system for analysis and monitoring (DSAM) of vibrations and acoustic noise, which consists of an array of intelligent modules, sensor modules, communication bus and a host PC acting as data center. The main advantages of the DSAM are its modularity, scalability, and flexibility for use of different type of sensors/transducers, with analog or digital outputs, and for signals of different nature. Its final cost is also significantly lower than other available commercial solutions. The system is reconfigurable, can operate either with synchronous or asynchronous modes, with programmable sampling frequencies, 8-bit or 12-bit resolution and a memory buffer of 15 kbyte. It allows real-time data-acquisition for signals of different nature, in applications that require a large number of sensors, thus it is suited for monitoring of vibrations in Linear Switched Reluctance Actuators (LSRAs). The acquired data allows the full characterization of the LSRA in terms of its response to vibrations of structural origins, and the vibrations and acoustic noise emitted under normal operation. The DSAM can also be used for electrical machine condition monitoring, machine fault diagnosis, structural characterization and monitoring, among other applications. PMID:22969364

  15. An Intelligent Sensor Array Distributed System for Vibration Analysis and Acoustic Noise Characterization of a Linear Switched Reluctance Actuator

    PubMed Central

    Salvado, José; Espírito-Santo, António; Calado, Maria

    2012-01-01

    This paper proposes a distributed system for analysis and monitoring (DSAM) of vibrations and acoustic noise, which consists of an array of intelligent modules, sensor modules, communication bus and a host PC acting as data center. The main advantages of the DSAM are its modularity, scalability, and flexibility for use of different type of sensors/transducers, with analog or digital outputs, and for signals of different nature. Its final cost is also significantly lower than other available commercial solutions. The system is reconfigurable, can operate either with synchronous or asynchronous modes, with programmable sampling frequencies, 8-bit or 12-bit resolution and a memory buffer of 15 kbyte. It allows real-time data-acquisition for signals of different nature, in applications that require a large number of sensors, thus it is suited for monitoring of vibrations in Linear Switched Reluctance Actuators (LSRAs). The acquired data allows the full characterization of the LSRA in terms of its response to vibrations of structural origins, and the vibrations and acoustic noise emitted under normal operation. The DSAM can also be used for electrical machine condition monitoring, machine fault diagnosis, structural characterization and monitoring, among other applications. PMID:22969364

  16. The Feasibility of Generalized Acoustic Sensor Operator Training. Final Report for Period February 1974-February 1975.

    ERIC Educational Resources Information Center

    Daniels, Richard W.; Alden, David G.

    The feasibility of generalized approaches to training military personnel in the use of different types of sonar/acoustic warfare systems was explored. The initial phase of the project consisted of the analysis of representative sonar and acoustic equipment to identify training areas and operator performance requirements that could be subjected to…

  17. Comparisons of polymer/gas partition coefficients calculated from responses of thickness shear mode and surface acoustic wave vapor sensors.

    PubMed

    Grate, J W; Kaganove, S N; Bhethanabotla, V R

    1998-01-01

    Apparent partition coefficients, K, for the sorption of toluene by four different polymer thin films on thickness shear mode (TSM) and surface acoustic wave (SAW) devices are compared. The polymers examined were poly(isobutylene) (PIB), poly(epichlorohydrin) (PECH), poly(butadiene) (PBD), and poly(dimethylsiloxane) (PDMS). Independent data on partition coefficients for toluene in these polymers were compiled for comparison, and TSM sensor measurements were made using both oscillator and impedance analysis methods. K values from SAW sensor measurements were about twice those calculated from TSM sensor measurements when the polymers were PIB and PECH, and they were also at least twice the values of the independent partition coefficient data, which is interpreted as indicating that the SAW sensor responds to polymer modulus changes as well as to mass changes. K values from SAW and TSM measurements were in agreement with each other and with independent data when the polymer was PBD. Similarly, K values from the PDMS-coated SAW sensor were not much larger than values from independent measurements. These results indicate that modulus effects were not contributing to the SAW sensor responses in the cases of PBD and PDMS. However, K values from the PDMS-coated TSM device were larger than the values from the SAW device or independent measurements, and the impedance analyzer results indicated that this sensor using our sample of PDMS at the applied thickness did not behave as a simple mass sensor. Differences in behavior among the test polymers on SAW devices are interpreted in terms of their differing viscoelastic properties. PMID:21644612

  18. Improved Airborne Gravity Results Using New Relative Gravity Sensor Technology

    NASA Astrophysics Data System (ADS)

    Brady, N.

    2013-12-01

    Airborne gravity data has contributed greatly to our knowledge of subsurface geophysics particularly in rugged and otherwise inaccessible areas such as Antarctica. Reliable high quality GPS data has renewed interest in improving the accuracy of airborne gravity systems and recent improvements in the electronic control of the sensor have increased the accuracy and ability of the classic Lacoste and Romberg zero length spring gravity meters to operate in turbulent air conditions. Lacoste and Romberg type gravity meters provide increased sensitivity over other relative gravity meters by utilizing a mass attached to a horizontal beam which is balanced by a ';zero length spring'. This type of dynamic gravity sensor is capable of measuring gravity changes on the order of 0.05 milliGals in laboratory conditions but more commonly 0.7 to 1 milliGal in survey use. The sensor may have errors induced by the electronics used to read the beam position as well as noise induced by unwanted accelerations, commonly turbulence, which moves the beam away from its ideal balance position otherwise known as the reading line. The sensor relies on a measuring screw controlled by a computer which attempts to bring the beam back to the reading line position. The beam is also heavily damped so that it does not react to most unwanted high frequency accelerations. However this heavily damped system is slow to react, particularly in turns where there are very high Eotvos effects. New sensor technology utilizes magnetic damping of the beam coupled with an active feedback system which acts to effectively keep the beam locked at the reading line position. The feedback system operates over the entire range of the system so there is now no requirement for a measuring screw. The feedback system operates at very high speed so that even large turbulent events have minimal impact on data quality and very little, if any, survey line data is lost because of large beam displacement errors. Airborne testing

  19. Portable reconfigurable line sensor (PRLS) and technology transfer

    SciTech Connect

    MacKenzie, D.P.; Buckle, T.H.; Blattman, D.A.

    1993-12-31

    The Portable Reconfigurable Line Sensor (PRLS) is a bistatic, pulsed-Doppler, microwave intrusion detection system developed at Sandia National Laboratories for the US Air Force. The PRLS is rapidly and easily deployed, and can detect intruders ranging from a slow creeping intruder to a high speed vehicle. The system has a sharply defined detection zone and will not falsely alarm on nearby traffic. Unlike most microwave sensors, the PRLS requires no alignment or calibration. Its portability, battery operation, ease of setup, and RF alarm reporting capability make it an excellent choice for perimeter, portal, and gap-filler applications in the important new field of rapidly-deployable sensor systems. In October 1992, the US Air Force and Racon, Inc., entered into a Cooperative Research and Development Agreement (CRADA) to commercialize the PRLS, jointly sharing government and industry resources. The Air Force brings the user`s perspective and requirements to the cooperative effort. Sandia, serving as the technical arm of the Air Force, adds the actual PRLS technology to the joint effort, and provides security systems and radar development expertise. Racon puts the Air Force requirements and Sandia technology together into a commercial product, making the system meet important commercial manufacturing constraints. The result is a true ``win-win`` situation, with reduced government investment during the commercial development of the PRLS, and industry access to technology not otherwise available.

  20. Technological, biological, and acoustical constraints to music perception in cochlear implant users.

    PubMed

    Limb, Charles J; Roy, Alexis T

    2014-02-01

    Despite advances in technology, the ability to perceive music remains limited for many cochlear implant users. This paper reviews the technological, biological, and acoustical constraints that make music an especially challenging stimulus for cochlear implant users, while highlighting recent research efforts to overcome these shortcomings. The limitations of cochlear implant devices, which have been optimized for speech comprehension, become evident when applied to music, particularly with regards to inadequate spectral, fine-temporal, and dynamic range representation. Beyond the impoverished information transmitted by the device itself, both peripheral and central auditory nervous system deficits are seen in the presence of sensorineural hearing loss, such as auditory nerve degeneration and abnormal auditory cortex activation. These technological and biological constraints to effective music perception are further compounded by the complexity of the acoustical features of music itself that require the perceptual integration of varying rhythmic, melodic, harmonic, and timbral elements of sound. Cochlear implant users not only have difficulty perceiving spectral components individually (leading to fundamental disruptions in perception of pitch, melody, and harmony) but also display deficits with higher perceptual integration tasks required for music perception, such as auditory stream segregation. Despite these current limitations, focused musical training programs, new assessment methods, and improvements in the representation and transmission of the complex acoustical features of music through technological innovation offer the potential for significant advancements in cochlear implant-mediated music perception. PMID:23665130

  1. Wireless Sensors: Technology and Cost-Savings for Commercial Buildings

    SciTech Connect

    Kintner-Meyer, Michael CW; Brambley, Michael R.; Carlon, Teresa A.; Bauman, Nathan N.

    2002-08-30

    Two projects under way for the U.S. Department of Energy Office of Building Technology, State and Community Programs, aim to adapt, test and demonstrate wireless sensors and data acquisition for heating, ventilating, and air-conditioning (HVAC) in commercial buildings. One project focuses on built-up systems in medium to large buildings; the second on applications for rooftop units in small- to medium-size facilities. In this paper, the authors present the technical characteristics and costs of off-the-shelf wireless sensor and data-acquisition systems and describe how they can be adapted to commercial buildings. The first part of the paper discusses the appropriateness of the different wireless protocols and then uses a "low-cost" and "high-cost" scenario later in the paper for comparison to wired systems. The paper provides a brief overview of wireless communication standards and discusses their appropriateness to HVAC control applications. The authors describe two wireless technology demonstration projects and discuss the limitations of today's technology and how wireless technology might be improved to reduce costs. Finally, a cost comparison between wired and wireless control networks for retrofit and new construction is presented to provide insights into the key drivers that determine the cost competitive of wireless technologies for HVAC control applications.

  2. Biotin-Streptavidin Binding Interactions of Dielectric Filled Silicon Bulk Acoustic Resonators for Smart Label-Free Biochemical Sensor Applications

    PubMed Central

    Heidari, Amir; Yoon, Yong-Jin; Park, Woo-Tae; Su, Pei-Chen; Miao, Jianmin; Lin, Julius Tsai Ming; Park, Mi Kyoung

    2014-01-01

    Sensor performance of a dielectric filled silicon bulk acoustic resonator type label-free biosensor is verified with biotin-streptavidin binding interactions as a model system. The mass sensor is a micromachined silicon square plate with a dielectric filled capacitive excitation mechanism. The resonance frequency of the biotin modified resonator decreased 315 ppm when exposed to streptavidin solution for 15 min with a concentration of 10−7 M, corresponding to an added mass of 3.43 ng on the resonator surface. An additional control is added by exposing a bovine serum albumin (BSA)-covered device to streptavidin in the absence of the attached biotin. No resonance frequency shift was observed in the control experiment, which confirms the specificity of the detection. The sensor-to-sensor variability is also measured to be 4.3%. Consequently, the developed sensor can be used to observe in biotin-streptavidin interaction without the use of labelling or molecular tags. In addition, biosensor can be used in a variety of different immunoassay tests. PMID:24608003

  3. Biotin-streptavidin binding interactions of dielectric filled silicon bulk acoustic resonators for smart label-free biochemical sensor applications.

    PubMed

    Heidari, Amir; Yoon, Yong-Jin; Park, Woo-Tae; Su, Pei-Chen; Miao, Jianmin; Lin, Julius Tsai Ming; Park, Mi Kyoung

    2014-01-01

    Sensor performance of a dielectric filled silicon bulk acoustic resonator type label-free biosensor is verified with biotin-streptavidin binding interactions as a model system. The mass sensor is a micromachined silicon square plate with a dielectric filled capacitive excitation mechanism. The resonance frequency of the biotin modified resonator decreased 315 ppm when exposed to streptavidin solution for 15 min with a concentration of 10(-7) M, corresponding to an added mass of 3.43 ng on the resonator surface. An additional control is added by exposing a bovine serum albumin (BSA)-covered device to streptavidin in the absence of the attached biotin. No resonance frequency shift was observed in the control experiment, which confirms the specificity of the detection. The sensor-to-sensor variability is also measured to be 4.3%. Consequently, the developed sensor can be used to observe in biotin-streptavidin interaction without the use of labelling or molecular tags. In addition, biosensor can be used in a variety of different immunoassay tests. PMID:24608003

  4. Sensors and nuclear power. Report by the Technology Transfer Sensors Task Team

    SciTech Connect

    Not Available

    1985-06-01

    The existing sensor systems for the basic process parameters in nuclear power plant operation have limitations with respect to accuracy, ease of maintenance and signal processing. These limitations comprise the economy of nuclear power generation. To reduce the costs and improve performance of nuclear power plant fabrication, operation, maintenance and repair we need to advance the sensor technology being applied in the nuclear industry. The economic viability and public acceptance of nuclear power will depend on how well we direct and apply technological advances to the industry. This report was prepared by a team with members representing a wide range of the nuclear industry embracing the university programs, national laboratories, architect engineers and reactor manufacturers. An intensive effort was made to survey current sensor technology, evaluate future trends and determine development needs. This included literature surveys, visits with utilities, universities, laboratories and organizations outside the nuclear industry. Several conferences were attended to take advantage of the access to experts in selected topics and to obtain opinions. Numerous telephone contacts and exchanges by mail supplemented the above efforts. Finally, the broad technical depth of the team members provided the basis for the stimulating working sessions during which this report was organized and drafted.

  5. Fly eye radar or micro-radar sensor technology

    NASA Astrophysics Data System (ADS)

    Molchanov, Pavlo; Asmolova, Olga

    2014-05-01

    To compensate for its eye's inability to point its eye at a target, the fly's eye consists of multiple angularly spaced sensors giving the fly the wide-area visual coverage it needs to detect and avoid the threats around him. Based on a similar concept a revolutionary new micro-radar sensor technology is proposed for detecting and tracking ground and/or airborne low profile low altitude targets in harsh urban environments. Distributed along a border or around a protected object (military facility and buildings, camp, stadium) small size, low power unattended radar sensors can be used for target detection and tracking, threat warning, pre-shot sniper protection and provides effective support for homeland security. In addition it can provide 3D recognition and targets classification due to its use of five orders more pulses than any scanning radar to each space point, by using few points of view, diversity signals and intelligent processing. The application of an array of directional antennas eliminates the need for a mechanical scanning antenna or phase processor. It radically decreases radar size and increases bearing accuracy several folds. The proposed micro-radar sensors can be easy connected to one or several operators by point-to-point invisible protected communication. The directional antennas have higher gain, can be multi-frequency and connected to a multi-functional network. Fly eye micro-radars are inexpensive, can be expendable and will reduce cost of defense.

  6. A SAW-Based Chemical Sensor for Detecting Sulfur-Containing Organophosphorus Compounds Using a Two-Step Self-Assembly and Molecular Imprinting Technology

    PubMed Central

    Pan, Yong; Yang, Liu; Mu, Ning; Shao, Shengyu; Wang, Wen; Xie, Xiao; He, Shitang

    2014-01-01

    This paper presents a new effective approach for the sensitive film deposition of surface acoustic wave (SAW) chemical sensors for detecting organophosphorus compounds such as O-ethyl-S-2-diisopropylaminoethyl methylphosphonothiolate (VX) containing sulfur at extremely low concentrations. To improve the adsorptive efficiency, a two-step technology is proposed for the sensitive film preparation on the SAW delay line utilizing gold electrodes. First, mono[6-deoxy-6-[(mercaptodecamethylene)thio

  7. Characterization, Monitoring, and Sensor Technology Integrated Program (CMST-IP). Technology summary

    SciTech Connect

    Not Available

    1994-04-01

    The Characterization, Monitoring, and Sensor Technology Integrated Program seeks to deliver needed technologies, timely and cost-effectively, to the Office of Waste Management (EM-30), the Office of Environmental Restoration (EM-40), and the Office of Facility Transition and Management (EM-60). The scope of characterizations monitoring, and sensor technology needs that are required by those organizations encompass: (1) initial location and characterization of wastes and waste environments - prior to treatment; (2) monitoring of waste retrieval, remediation and treatment processes; (3) characterization of the co-position of final waste treatment forms to evaluate the performance of waste treatments processes; and (4) site closure and compliance monitoring. Wherever possible, the CMST-IP fosters technology transfer and commercialization of technologies that it sponsors.

  8. Hybrid distributed acoustic and temperature sensor using a commercial off-the-shelf DFB laser and direct detection.

    PubMed

    Muanenda, Yonas; Oton, Claudio J; Faralli, Stefano; Nannipieri, Tiziano; Signorini, Alessandro; Di Pasquale, Fabrizio

    2016-02-01

    We demonstrate a hybrid distributed acoustic and temperature sensor (DATS) using a commercial off-the-shelf (COTS) distributed feedback (DFB) laser, a single-mode optical fiber, and a common receiver block. We show that the spectral and frequency noise characteristics of the laser, combined with a suitable modulation scheme, ensure the inter-pulse incoherence and intra-pulse coherence conditions required for exploiting the fast denoising benefits of cyclic Simplex pulse coding in the hybrid measurement. The proposed technique enables simultaneous, distributed measurement of vibrations and temperature, with key industrial applications in structural health monitoring and industrial process control systems. The sensor is able to clearly identify a 500 Hz vibration at 5 km distance along a standard single-mode fiber and simultaneously measure the temperature profile along the same fiber with a temperature resolution of less than 0.5°C with 5 m spatial resolution. PMID:26907430

  9. Smart fabric sensors and e-textile technologies: a review

    NASA Astrophysics Data System (ADS)

    Castano, Lina M.; Flatau, Alison B.

    2014-05-01

    This paper provides a review of recent developments in the rapidly changing and advancing field of smart fabric sensor and electronic textile technologies. It summarizes the basic principles and approaches employed when building fabric sensors as well as the most commonly used materials and techniques used in electronic textiles. This paper shows that sensing functionality can be created by intrinsic and extrinsic modifications to textile substrates depending on the level of integration into the fabric platform. The current work demonstrates that fabric sensors can be tailored to measure force, pressure, chemicals, humidity and temperature variations. Materials, connectors, fabric circuits, interconnects, encapsulation and fabrication methods associated with fabric technologies prove to be customizable and versatile but less robust than their conventional electronics counterparts. The findings of this survey suggest that a complete smart fabric system is possible through the integration of the different types of textile based functional elements. This work intends to be a starting point for standardization of smart fabric sensing techniques and e-textile fabrication methods.

  10. A new principle for low-cost hydrogen sensors for fuel cell technology safety

    NASA Astrophysics Data System (ADS)

    Liess, Martin

    2014-03-01

    Hydrogen sensors are of paramount importance for the safety of hydrogen fuel cell technology as result of the high pressure necessary in fuel tanks and its low explosion limit. I present a novel sensor principle based on thermal conduction that is very sensitive to hydrogen, highly specific and can operate on low temperatures. As opposed to other thermal sensors it can be operated with low cost and low power driving electronics. On top of this, as sensor element a modified standard of-the shelf MEMS thermopile IR-sensor can be used. The sensor principle presented is thus suited for the future mass markets of hydrogen fuel cell technology.S

  11. A new principle for low-cost hydrogen sensors for fuel cell technology safety

    SciTech Connect

    Liess, Martin

    2014-03-24

    Hydrogen sensors are of paramount importance for the safety of hydrogen fuel cell technology as result of the high pressure necessary in fuel tanks and its low explosion limit. I present a novel sensor principle based on thermal conduction that is very sensitive to hydrogen, highly specific and can operate on low temperatures. As opposed to other thermal sensors it can be operated with low cost and low power driving electronics. On top of this, as sensor element a modified standard of-the shelf MEMS thermopile IR-sensor can be used. The sensor principle presented is thus suited for the future mass markets of hydrogen fuel cell technology.S.

  12. The Citizen Science Toolbox: A One-Stop Resource for Air Sensor Technology

    EPA Science Inventory

    The air sensor technology market is exploding with new sensors in all kinds of forms. Developers are putting sensors in wristbands, headphones, and cell phone add-ons. Small, portable and lower-cost measurement devices using sensors are coming on the market with a wide variety of...

  13. Comparison of absolute and relative air humidity sensors fabricated with inkjet printing technology

    NASA Astrophysics Data System (ADS)

    Selma, R.; Tarapata, G.; Marzecki, M.

    2015-09-01

    This paper describes design, manufacturing and testing of novelty humidity sensors manufactured in inkjet printing technology. Two types of sensors were produced - sensor for dew point hygrometer, along with heater and thermistor, and a relative humidity sensor. Both were tested and proven to be functional, with both advantages and disadvantages described further in the article.

  14. Single stage, low noise advanced technology fan. Volume 3: Acoustic design

    NASA Technical Reports Server (NTRS)

    Kazin, S. B.; Mishler, R. B.

    1976-01-01

    The acoustic design for a half-scale fan vehicle, which would have application on an advanced transport aircraft, is described. The single stage advanced technology fan was designed to a pressure ratio of 1.8 at a tip speed of 503 m/sec (1,650 ft/sec). The two basic approaches taken in the acoustic design were: (1) minimization of noise at the source, and (2) suppression of the generated noise in the inlet and bypass exhaust duct. Suppression of the generated noise is accomplished in the inlet through use of the hybrid concept (wall acoustic treatment plus airflow acceleration suppression) and in the exhaust duct with extensive acoustic treatment including a splitter. The goal of the design was attainment of twenty effective perceived noise decibels (20 EPNdB) below current Federal Air Regulation noise standards for a full-scale fan at the takeoff, cutback, and approach conditions. Predicted unsuppressed and suppressed fore and aft maximum perceived noise levels indicate that the cutback condition is the most critical with respect to the goal, which is probably unattainable for that condition. This is also true for aft radiated noise in the approach condition.

  15. Research progress in the key device and technology for fiber optic sensor network

    NASA Astrophysics Data System (ADS)

    Liu, Deming; Sun, Qizhen; Lu, Ping; Xia, Li; Sima, Chaotan

    2016-03-01

    The recent research progress in the key device and technology of the fiber optic sensor network (FOSN) is introduced in this paper. An architecture of the sensor optical passive network (SPON), by employing hybrid wavelength division multiplexing/time division multiplexing (WDM/TDM) techniques similar to the fiber communication passive optical network (PON), is proposed. The network topology scheme of a hybrid TDM/WDM/FDM (frequency division multiplexing) three-dimension fiber optic sensing system for achieving ultra-large capacity, long distance, and high resolution sensing performance is performed and analyzed. As the most important device of the FOSN, several kinds of light source are developed, including the wideband multi-wavelength fiber laser operating at C band, switchable and tunable 2 μm multi-wavelength fiber lasers, ultra-fast mode-locked fiber laser, as well as the optical wideband chaos source, which have very good application prospects in the FOSN. Meanwhile, intelligent management techniques for the FOSN including wideband spectrum demodulation of the sensing signals and real-time fault monitoring of fiber links are presented. Moreover, several typical applications of the FOSN are also discussed, such as the fiber optic gas sensing network, fiber optic acoustic sensing network, and strain/dynamic strain sensing network.

  16. 78 FR 17187 - Notice of Intent To Grant Exclusive Patent License; Fiber Optic Sensor Systems Technology...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-20

    ... Department of the Navy Notice of Intent To Grant Exclusive Patent License; Fiber Optic Sensor Systems... to grant to Fiber Optic Sensor Systems Technology Corporation, a revocable, nonassignable, exclusive... its intent to grant to Fiber Optic Sensor Systems Technology Corporation a revocable,...

  17. Acoustic Source Localization via Time Difference of Arrival Estimation for Distributed Sensor Networks Using Tera-Scale Optical Core Devices

    DOE PAGESBeta

    Imam, Neena; Barhen, Jacob

    2009-01-01

    For real-time acoustic source localization applications, one of the primary challenges is the considerable growth in computational complexity associated with the emergence of ever larger, active or passive, distributed sensor networks. These sensors rely heavily on battery-operated system components to achieve highly functional automation in signal and information processing. In order to keep communication requirements minimal, it is desirable to perform as much processing on the receiver platforms as possible. However, the complexity of the calculations needed to achieve accurate source localization increases dramatically with the size of sensor arrays, resulting in substantial growth of computational requirements that cannot bemore » readily met with standard hardware. One option to meet this challenge builds upon the emergence of digital optical-core devices. The objective of this work was to explore the implementation of key building block algorithms used in underwater source localization on the optical-core digital processing platform recently introduced by Lenslet Inc. This demonstration of considerably faster signal processing capability should be of substantial significance to the design and innovation of future generations of distributed sensor networks.« less

  18. Acoustic fault injection tool (AFIT)

    NASA Astrophysics Data System (ADS)

    Schoess, Jeffrey N.

    1999-05-01

    On September 18, 1997, Honeywell Technology Center (HTC) successfully completed a three-week flight test of its rotor acoustic monitoring system (RAMS) at Patuxent River Flight Test Center. This flight test was the culmination of an ambitious 38-month proof-of-concept effort directed at demonstrating the feasibility of detecting crack propagation in helicopter rotor components. The program was funded as part of the U.S. Navy's Air Vehicle Diagnostic Systems (AVDS) program. Reductions in Navy maintenance budgets and available personnel have dictated the need to transition from time-based to 'condition-based' maintenance. Achieving this will require new enabling diagnostic technologies. The application of acoustic emission for the early detection of helicopter rotor head dynamic component faults has proven the feasibility of the technology. The flight-test results demonstrated that stress-wave acoustic emission technology can detect signals equivalent to small fatigue cracks in rotor head components and can do so across the rotating articulated rotor head joints and in the presence of other background acoustic noise generated during flight operation. During the RAMS flight test, 12 test flights were flown from which 25 Gbyte of digital acoustic data and about 15 hours of analog flight data recorder (FDR) data were collected from the eight on-rotor acoustic sensors. The focus of this paper is to describe the CH-46 flight-test configuration and present design details about a new innovative machinery diagnostic technology called acoustic fault injection. This technology involves the injection of acoustic sound into machinery to assess health and characterize operational status. The paper will also address the development of the Acoustic Fault Injection Tool (AFIT), which was successfully demonstrated during the CH-46 flight tests.

  19. Towards a history of Polish acoustics as part of the activity of the Institute of Basic Problems of Technology

    NASA Astrophysics Data System (ADS)

    Ranachowski, Jerzy

    As yet no detailed history of Polish acoustics exists. The easiest way to begin such an undertaking would be to start with a description of the history of specific teams led by a particular individual. The author has attempted to describe the contributions of a team of scientists working at the Institute of Basic Problems of Technology who worked closely with Professor Ignacy Malecki. The first Polish work in the field of acousticd began in the 1930's. Acoustics was taught at the clandestine Warsaw Polytechnical. A Department of Electroacoustics was established at the polytechnical. This department led to the establishment of the Vibration Research Institute of the Polish Academy of Sciences, which in 1953 became part of the academy's new Institute of Basic Problems of Technology. The Vibration Research Institute conducted acoustic research in the areas of ultrasound flaw detection, molecular acoustics, noise measurements, and speech acoustics. The institute was also engaged in theoretical research on electromechanical-acoustic analogies and coupled electroacoustic fields and theoretical and experimental studies of heterogeneous materials, especially ceramics. The institute became interested in hypersonics and quantum representations of acoustic phenomena. A quantum method was used to describe a diffraction field and the propagation of vibrations in a narrow passage. The institute went from measurements of the velocity and attenuation of ultrasound waves to a study of the active behavior of materials corresponding to acoustic emission. The institute conducted comprehensive studies of the mechanisms by which acoustic emission is generated and developed different applications for acoustic emission. Researchers investigated the acoustic emission which accompanies brittle fracture and chemical reactions. The institute cooperated with foreign researchers and engaged in educational activities related to its research.

  20. Concepts and Development of Bio-Inspired Distributed Embedded Wired/Wireless Sensor Array Architectures for Acoustic Wave Sensing in Integrated Aerospace Vehicles

    NASA Technical Reports Server (NTRS)

    Ghoshal, Anindya; Prosser, William H.; Kirikera, Goutham; Schulz, Mark J.; Hughes, Derke J.; Orisamolu, Wally

    2003-01-01

    This paper discusses the modeling of acoustic emissions in plate structures and their sensing by embedded or surface bonded piezoelectric sensor arrays. Three different modeling efforts for acoustic emission (AE) wave generation and propagation are discussed briefly along with their advantages and disadvantages. Continuous sensors placed at right angles on a plate are being discussed as a new approach to measure and locate the source of acoustic waves. Evolutionary novel signal processing algorithms and bio-inspired distributed sensor array systems are used on large structures and integrated aerospace vehicles for AE source localization and preliminary results are presented. These systems allow for a great reduction in the amount of data that needs to be processed and also reduce the chances of false alarms from ambient noises. It is envisioned that these biomimetic sensor arrays and signal processing techniques will be useful for both wireless and wired sensor arrays for real time health monitoring of large integrated aerospace vehicles and earth fixed civil structures. The sensor array architectures can also be used with other types of sensors and for other applications.