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Office of Scientific and Technical Information
Modeling the Performance of an Acoustic Doppler Current Profiler
Science Conference Proceedings (OSTI)
A systematic examination of measurement error in acoustic Doppler current profiler (ADCP) velocity estimates, in the limit of large signal-to-noise ratio, is made using a system model and sonar signal simulations coupled into an ADCP. The model ...
T. K. Chereskin; A. J. Harding
Operating an Acoustic Doppler Current Profiler aboard a Container Vessel
Since October 1992 an acoustic Doppler current profiler (ADCP) has been in near-continuous operation on board a 118-m-long container vessel, the container motor vessel Oleander, which operates on a weekly schedule between Port Elizabeth, New ...
C. N. Flagg; G. Schwartze; E. Gottlieb; T. Rossby
An Intercomparison of Current Measurements Using a Vector Measuring Current Meter, an Acoustic Doppler Current Profiler, and a Recently Developed Acoustic Current Meter
Horizontal current measurements were obtained simultaneously with a vector measuring current meter (VMCM), an acoustic Doppler current profiler (ADCP), and the recently developed Falmouth Scientific, Inc., acoustic current meter (ACM) during a ...
T. P. Gilboy; T. D. Dickey; D. E. Sigurdson; X. Yu; D. Manov
Effects of a Thermistor String Mounted between the Acoustic Beams of an Acoustic Doppler Current Profiler
A useful extension of upward-looking buoy-mounted acoustic Doppler current profilers (ADCPs), in particular for studying surface-mixed-layer dynamics from underneath, would be to combine them with a thermistor cable for obtaining simultaneous ...
Friedrich Schott
High-Resolution Directional Wave Spectra from Horizontally Mounted Acoustic Doppler Current Meters
The paper discusses the estimation of directional wave spectra by the Iterative Maximum Likelihood Method. The performance of the estimate is illustrated using data obtained by an Acoustic Doppler Current Meter in the CUrrent Measurement ...
Harald E. Krogstad; R. Lee Gordon; Martin C. Miller
Performance and Calibration of an Acoustic Doppler Current Profiler Towed below the Surface
A towed acoustic Doppler current profiler (ADCP) system was tested. The instrument was deployed from ships of opportunity and towed at depths between 5 and 25 m. The towed system carries upward- and downward-looking ADCPs. The instrument platform ...
Andreas Münchow; Charles S. Coughran; Myrl C. Hendershott; Clinton D. Winant
Observations with Moored Acoustic Doppler Current Profilers in the Convection Regime in the Golfe du Lion
In the Golfe du Lion, south of France, favorable conditions for deep winter convection exist and were documented by the MEDOC experiments during 1969–75. A renewed investigation of that regime with upward-looking moored acoustic Doppler current ...
Friedrich Schott; Kevin D. Leaman
Identifying and Screening Filter Skew and Noise Bias in Acoustic Doppler Current Profiler Measurements
Acoustic Doppler current profiler (ADCP) velocity measurements an subject to bias due to the effect of the signal processing filters on the spectrum of the Doppler-shifted signal and on the noise. Bias will occur when the filter is not centered ...
T. K. Chereskin; E. Firing; J. A. Gast
Improving Acoustic Doppler Current Profiler Accuracy with Wide-Area Differential GPS and Adaptive Smoothing of Ship Velocity
Accurate ship velocity is important for determining absolute currents from acoustic Doppler current profiler (ADCP) measurements. In this paper, the authors describe the application of two methods to improve the quality of ship velocity ...
Stephen D. Pierce; John A. Barth; Robert L. Smith
Application of an Acoustic Doppler Current Profiler to Measure Hydro Plant Diversion Flows
For most conventional and pumped-storage hydroelectric plants, accurate and timely knowledge of flow rates is important for cost-effective operation. Acoustic Doppler technology has not been applied in a large power plant intake channel until this project.
A Study of Geostrophy in Tropical Pacific Ocean Currents during the NORPAX Tahiti Shuttle using a Shipboard Doppler Acoustic Current Profiler
Continuous velocity measurements from a shipboard Doppler acoustic long on the NORPAX shuttle experiment in the central equatorial Pacific are presented. The time mean of these velocities shows the classical zonal equatorial currents as well as ...
Eric S. Johnson; Lloyd A. Regier; Robert A. Knox
Acoustic Doppler Current Profiler Surveys of Velocity Downstream of Albeni Falls Dam
DOE Green Energy (OSTI)
The U.S. Army Corps of Engineers (USACE), Seattle District, is studying the potential to locate fish bypass systems at Albeni Falls Dam. The USACE requested Pacific Northwest National Laboratory (PNNL) to survey velocity magnitude and direction in the dam tailrace. The empirical data collected will be used to support future numerical modeling, physical modeling, and evaluation of fish bypass system alternatives. In May 2010, PNNL conducted velocity surveys of the Albeni Falls Dam using a boat-mounted acoustic Doppler current profiler. The surveys were conducted over three days (May 25 through 27). During the survey period, total river discharge at the dam varied between 30.2 and 31.0 kcfs. A small amount of spill discharge, 2 kcfs, was present on two days (May 26 and 27). This report presents data plots showing measured velocity direction and magnitude averaged over the entire depth and over 5-ft depth increments from 5 to 30 ft.
Perkins, William A.; Titzler, P. Scott; Richmond, Marshall C.; Serkowski, John A.; Kallio, Sara E.; Bellgraph, Brian J.
Acoustic Doppler Current Profiler Measurements in the Tailrace at John Day Dam
Acoustic Doppler current profilers (ADCPs) were used to measure water velocities in the tailrace at John Day Dam over a two-week period in February 2005. Data were collected by the Pacific Northwest National Laboratory for the Hydraulic Design Section, Portland District, U.S. Army Corps of Engineers (USACE). The objective of this project was therefore to collect field measurements of water velocities in the near-field draft tube exit zone as well as the far-field tailrace to be used for improving these models. Field data were collected during the project using five separate ADCPs. Mobile ADCP data were collected using two ADCPs mounted on two separate boats. Data were collected by either holding the boat on-station at pre-defined locations for approximately 10 minutes or in moving transect mode when the boat would move over large distances during the data collection. Results from the mobile ADCP survey indicated a complex hydrodynamic flow field in the tailrace downstream of John Day Dam. A large gyre was noted between the skeleton section of the powerhouse and non-spilling portion of the spillway. Downstream of the spillway, the spillway flow is constrained against the navigation lock guide wall, and large velocities were noted in this region. Downstream of the guide wall, velocities decreased as the spillway jet dispersed. Near the tailrace island, the flow split was measured to be approximately equal on Day 2 (25.4 kcfs spillway/123 kcfs total). However, approximately 60% of the flow passed along the south shore of the island on Day 1 (15.0 kcfs spillway/150 kcfs total). At a distance of 9000 ft downstream of the dam, flows had equalized laterally and were generally uniform over the cross section. The collection of water velocities near the draft tube exit of an operating turbine unit is not routine, and equipment capable of measuring 3D water velocities in these zones are at the forefront of hydraulic measurement technology. Although the feasibility of measuring 1D water velocity magnitudes has been previously demonstrated by the authors, the feasibility of resolving 3D water velocity vectors given the heterogeneity of the flow field was unknown before this study's data were collected. Both the 1D and 3D data were collected by deploying three ADCPs on dual-axis rotators directly above the draft tube exit of Turbine Unit 16. These instruments collected 1D data during both the mobile reconnaissance campaign and a later one-week period with zero spillway discharge. During the zero spillway discharge period, Turbine Unit 16 was operated over a range of discharges. Approximately 12 hours of 1D velocity data were collected at low (12 kcfs), middle (16.2 kcfs), and high (19.2 kcfs) turbine discharges. The 1D dataset indicates large differences in flow patterns and RMS velocity fluctuations among the various discharge levels. Results from this project show that it is technically feasible to measure 3D water velocities directly downstream of an operating turbine unit using a narrow beam swath (i.e., 6-degree) ADCP. Data products from these 3D velocity data include a measurement of the draft tube barrel flow distribution (a.k.a., the flow split), directional changes and the general decay of velocity as flow exits the draft tube and enters the tailrace, and a relative measure of the homogeneity of the flow field.
Cook, Chris B.; Dibrani, Berhon; Serkowski, John A.; Richmond, Marshall C.; Titzler, P. Scott; Dennis, Gary W.
Comparison of Buoy-Mounted 75-kHz Acoustic Doppler Current Profilers with Vector-Measuring Current Meters
Long time series of atmospheric parameters and limited oceanographic parameters such as near-surface temperature and wave statistics have been available for some time. There is, however, a need for similar observations of currents in the coastal ...
Clinton Winant; Theodore Mettlach; Sigurd Larson
Evaluation of the Acoustic Doppler Velocimeter (ADV) for Turbulence Measurements*
Accuracy of the acoustic Doppler velocimeter (ADV) is evaluated in this paper. Simultaneous measurements of open-channel flow were undertaken in a 17-m flume using an ADV and a laser Doppler velocimeter. Flow velocity records obtained by both ...
G. Voulgaris; J. H. Trowbridge
An Acoustic Doppler and Electromagnetic Velocity Profiler
A freely failing current meter called the Absolute Velocity Profiler (AVP) is described. This profiler is an expansion of a previously developed instrument, the Electro-Magnetic Velocity Profiler (EMVP), with the additional capability of acoustic ...
Thomas B. Sanford; Robert G. Driver; John H. Dunlap
Intercomparison of Wind Measurements from Two Acoustic Doppler Sodars, a Laser Doppler Lidar, and In Situ Sensors
Intercomparative measurements of wind speed, wind direction, wind direction standard deviation, and vertical wind standard deviation from two acoustic Doppler sodars and a laser Doppler lidar are studied, using the BAO tower to provide reference ...
Prasan Chintawongvanich; Robert Olsen; Christopher A. Biltoft
Improved Turbulence Profiling with Field-Adapted Acoustic Doppler Velocimeters Using a Bifrequency Doppler Noise Suppression Method
A novel noise reduction method and corresponding technique are presented for improving turbulence measurements with acoustic Doppler velocimeters (ADVs) commonly used in field studies of coastal and nearshore regions, rivers, lakes, and ...
D. Hurther; U. Lemmin
An Intercomparison of Acoustic Current Meter Measurements in Low to Moderate Flow Regions
Instrumented, subsurface moorings deployed in the Scotian shelf and slope regions of the North Atlantic provide data in low to moderate flows for a current meter intercomparison. The primary instruments being evaluated are two acoustic Doppler ...
Adam Drozdowski; Blair J. W. Greenan
Quality Controlling Surf Zone Acoustic Doppler Velocimeter Observations to Estimate the Turbulent Dissipation Rate
High-quality measurements of the turbulent dissipation rate ? are required to diagnose field surf-zone turbulence budgets. Quality control (QC) methods are presented for estimating surf zone ? with acoustic Doppler velocimeter (ADV) data. Bad ADV ...
Falk Feddersen
Acoustic Doppler Velocimeter Flow Measurement from an Autonomous Underwater Vehicle with Applications to Deep Ocean Convection
The authors present a new modality for direct measurement of ocean flow, achieved by combining the resolution and precision of an acoustic Doppler velocimeter with the mobility of an autonomous underwater vehicle. To obtain useful measurements, ...
Yanwu Zhang; Knut Streitlien; James G. Bellingham; Arthur B. Baggeroer
A Correction Method for Turbulence Measurements with a 3D Acoustic Doppler Velocity Profiler
A method is proposed to reduce the noise contribution to mean turbulence parameters obtained by 3D acoustic Doppler velocity profiler measurements. It is based on a noise spectrum reconstruction from cross-spectra evaluations of two independent ...
Analysis of Bottom-Track and Compass Error in a Self-Contained Acoustic Doppler Diver Navigation Console
The Cobra-Tac (Teledyne RD Instruments) is a self-contained diver navigation system based on acoustic Doppler velocity log (DVL) technology that uses dead reckoning to compute displacements from a known starting point. The navigational accuracy ...
James L. Hench; Johanna H. Rosman
A New Method for Measuring Flow Structure in the Benthic Boundary Layer Using an Acoustic Doppler Velocimeter
A new system for precise measurement of vertical profiles of mean and turbulent flow structure immediately above the sediment–water interface is introduced. This system has an acoustic Doppler velocimeter (ADV) attached to an elevation system to ...
Tetsunori Inoue; Yoshiyuki Nakamura; Mikio Sayama
Polaris: A GPS-Navigated Ocean Acoustic Current Profiler
Results from an initial feasibility study to test whether Global Positioning System (GPS) navigation can be combined with more traditional acoustic methods to measure ocean current profiles are presented. A typical acoustic current profiler such ...
Kevin D. Leaman; Peter S. Vertes; Chris Rocken
Internal Tides Observed by an Acoustic Doppler Current Profiler
Previous studies of Knight Inlet, British Columbia, revealed the presence of a strong internal M2 tide. Most of the energy was found to be in either the first or second dynamic modes. Due to difficulties in sampling of the surface layer, ...
R. F. Marsden; K. C. Greenwood
Acoustical Measurement of Current and Vorticity beneath Ice
An acoustical instrument has been developed to measure path-averaged horizontal current and vorticity in the subice boundary layer of the eastern Arctic during the spring of 1989. A triangular acoustic array of side 200 m was used to obtain ...
Dimitris Menemenlis; David M. Farmer
Mesoscale Current Fields Observed with a Shipboard Profiling Acoustic Current Meter
Measurements of the near-surface currents obtained with a shipboard profiling acoustic current meter during the POLYMODE Local Dynamics Experiment are discussed. The large-scale spatial structure of the directly measured currents is very similar ...
Lloyd Regier
Laser-Doppler acoustic probing of granular media with in-depth property gradient and varying pore pressures
Non-contacting ultrasonic techniques recently proved to be efficient in the physical modeling of seismic-wave propagation at various application scales, as for instance in the context of geological analogue and seismic modeling. An innovative experimental set-up is proposed here to perform laser-Doppler acoustic probing of unconsolidated granular media with varying pore pressures. The preliminary experiments presented here provide reproducible results and exploitable data, thus validating both the proposed medium preparation and pressure gradient generation procedure.
Bodet, L.; Dhemaied, A.; Mourgues, R.; Tournat, V.; Rejiba, F. [LPG, UMR CNRS 6112, Universite du Maine, Le Mans (France); UMR CNRS 7619 Sisyphe, Universite Pierre et Marie Curie-Paris 6 (France); LPG, UMR CNRS 6112, Universite du Maine, Le Mans (France); LAUM, CNRS, Universite du Maine, Le Mans (France); UMR CNRS 7619 Sisyphe, Universite Pierre et Marie Curie-Paris 6 (France)
Current Meter Performance in the Surf Zone
Statistics of the nearshore velocity field in the wind–wave frequency band estimated from acoustic Doppler, acoustic travel time, and electromagnetic current meters are similar. Specifically, current meters deployed 25–100 cm above the seafloor ...
Steve Elgar; Britt Raubenheimer; R. T. Guza
Performance of a New Generation of Acoustic Current Meters
As part of a program aimed at developing a long-duration, subsurface mooring, known as Ultramoor, several modern acoustic current meters were tested. The instruments with which the authors have the most experience are the Aanderaa RCM11 and the ...
Nelson G. Hogg; Daniel E. Frye
Ion acoustic solitons in Earth's upward current region
The formation and evolution of ion acoustic solitons in Earth's auroral upward current region are studied using one- and two-dimensional (2D) electrostatic particle-in-cell simulations. The one-dimensional simulations are confined to processes that occur in the auroral cavity and include four plasma populations: hot electrons, H{sup +} and O{sup +} anti-earthward ion beams, and a hot H{sup +} background population. Ion acoustic solitons are found to form for auroral-cavity ion beams consistent with acceleration through double-layer (DL) potentials measured by FAST. A simplified one-dimensional model simulation is then presented in order to isolate the mechanisms that lead to the formation of the ion acoustic soliton. Results of a two-dimensional simulation, which include both the ionosphere and the auroral cavity, separated by a low-altitude DL, are then presented in order to confirm that the soliton forms in a more realistic 2D geometry. The 2D simulation is initialized with a U-shaped potential structure that mimics the inferred shape of the low altitude transition region based on observations. In this simulation, a soliton localized perpendicular to the geomagnetic field is observed to form and reside next to the DL. Finally, the 2D simulation results are compared with FAST data and it is found that certain aspects of the data can be explained by assuming the presence of an ion acoustic soliton.
Main, D. S.; Scholz, C. [Department of Physics, John Brown University, Siloam Springs, Arkansas 72761 (United States); Newman, D. L. [Center for Integrated Plasma Studies, University of Colorado, Boulder, Colorado 80309 (United States); Ergun, R. E. [Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, Colorado 80303 (United States)
Doppler Sodar and Radar Wind-Profiler Observations Of Gravity-Wave Activity Associated with a Gravity Current
Observations from two Doppler sodars and a radar wind profiler have been used in conjunction with data from a rawinsonde station and a mesoscale surface observation network to conduct a case study of a gravity current entering into an environment ...
F. M. Ralph; C. Mazaudier; M. Crochet; S. V. Venkateswaran
Filamentation instability of current-driven dust ion-acoustic waves in a collisional dusty plasma
A theoretical investigation has been made of the dust ion-acoustic filamentation instability in an unmagnetized current-driven dusty plasma by using the Lorentz transformation formulas. The effect of collision between the charged particles with neutrals and their thermal motion on this instability is considered. Developing the filamentation instability of the current-driven dust ion-acoustic wave allows us to determine the period and the establishment time of the filamentation structure and threshold for instability development.
Niknam, A. R. [Laser and Plasma Research Institute, Shahid Beheshti University, G.C., Tehran 19839-63113 (Iran, Islamic Republic of); Haghtalab, T.; Khorashadizadeh, S. M. [Physics Department, Birjand University, Birjand 97179-63384 (Iran, Islamic Republic of)
Low-Frequency Current Observations in the Korea/Tsushima Strait
High resolution, continuous current measurements made in the Korea/Tsushima Strait between May 1999 and March 2000 are used to examine current variations having time periods longer than 2 days. Twelve bottom-mounted acoustic Doppler current ...
W. J. Teague; G. A. Jacobs; H. T. Perkins; J. W. Book; K-I. Chang; M-S. Suk
Comparison of Different Bin-mapping Methods for a Bottom-mounted Acoustic Profiler
Acouste Doppler current profilers (ADCPS) can measure profiles of velocity components and some other properties of bodies of water. If the profiler is firmly mounted, the profiles can be recorded without immediate coordinate transform. This gives ...
Kari Pulkkinen
Dust-acoustic filamentation of a current-driven dusty plasma
The thermal motion effect of charged particles in the filamentation of a current-driven dusty plasma in the dust-acoustic frequency region is investigated by using the Lorentz transformed conductivity of the dusty plasma components and the total dielectric permittivity tensor of the dusty plasma in the laboratory frame. Obtaining the dispersion relation for dust-acoustic waves and considering the filamentation instability, the establishment time of the filamentation structure and the instability development threshold are derived. Moreover, it is shown that the current layer divides into separate current filaments.
Khorashadizadeh, S. M.; Haghtalab, T. [Physics Department, Birjand University, Birjand, 97179-63384 (Iran, Islamic Republic of); Niknam, A. R. [Laser and Plasma Research Institute, Shahid Beheshti University, G.C., Tehran, 19839-63113 (Iran, Islamic Republic of)
Comparison of Profiling Current Meter and Shipboard ADCP Measurements in the Western Equatorial Pacific
Profiling current meter (PCM) measurements under a drifting buoy are compared with concurrent shipboard acoustic Doppler current profiler (ADCP) measurements carried out in the western equatorial Pacific in March 1991, from 10°S to 7°N along the ...
Thierry Delcroix; François Masia; Gérard Eldin
Tropical Instability Wave Variability in the Pacific and Its Relation to Large-Scale Currents
Shipboard acoustic Doppler current profiler (ADCP)-derived zonal currents from 170° to 110°W are assembled into composite seasonal and ENSO cycles to produce detailed representations of large-scale ocean flow regimes that favor tropical ...
Eric S. Johnson; Jeffrey A. Proehl
Measurement of Turbulence in the Oceanic Bottom Boundary layer with an Acoustic Current Meter Array
A vertical array of acoustic current meters measures the vector flow field in the lowest 5 m of the oceanic boundary layer. By resolving the velocity to 0.03 cm s?1 over 15 cm paths, it samples the dominant turbulent eddies responsible for ...
Albert J. Williams 3rd; John S. Tochko; Richard L. Koehler; William D. Grant; Thomas F. Gross; Christopher V. R. Dunn
Current Patterns in the Inner Sound (Pentland Firth) from Underway ADCP Data
Numerous acoustic Doppler current profiler (ADCP) surveys were performed in the Inner Sound of the Pentland Firth, a channel between the Orkney Islands and the northern coast of Scotland connecting the Atlantic Ocean to the west and the North Sea ...
Lonneke Goddijn-Murphy; David K. Woolf; Matthew C. Easton
Surveying the Upper Ocean with the Ocean Surveyor: A New Phased Array Doppler Current Profiler
A new shipboard current profiler, a 75-kHz ocean surveyor, was operationally used during two research cruises in the tropical Atlantic and the subpolar North Atlantic, respectively. Here, a report is presented on the first experience with this ...
Jürgen Fischer; Peter Brandt; Marcus Dengler; Mario Müller; Darryl Symonds
Mesoscale Currents on the Inner New Jersey Shelf Driven by the Interaction of Buoyancy and Wind Forcing
Shipboard hydrographic and acoustic Doppler current profiler surveys conducted in August 1996 on the New Jersey inner shelf revealed a buoyant intrusion advancing southward along the coast. This buoyant intrusion originated from the Hudson ...
Alexander E. Yankovsky; Richard W. Garvine; Andreas Münchow
Vertical Velocity and Vertical Heat Flux Observed within Loop Current Eddies in the Central Gulf of Mexico
Sixteen months of observations from a surface-to-bottom mooring in the central Gulf of Mexico show that acoustic Doppler current profilers (ADCPs) are useful for directly measuring the vertical velocity within mesoscale anticyclonic eddies, such ...
David Rivas; Antoine Badan; Julio Sheinbaum; José Ochoa; Julio Candela
Networked Acoustic Modems for Real-Time Data Telemetry from Distributed Subsurface Instruments in the Coastal Ocean: Application to Array of Bottom-Mounted ADCPs
Through the winter and spring of 2002, networked acoustic modems demonstrated real-time wireless data telemetry from an array of bottom-mounted acoustic Doppler current profilers (ADCPs) on the inner continental shelf 20–60 m deep off of Montauk ...
Daniel L. Codiga; Joseph A. Rice; Paul A. Baxley; David Hebert
Current and Density Observations across the Wake of Hurricane Gay
CTD and acoustic Doppler current profiler data are analyzed for the response of the upper ocean to rapidly moving Hurricane Gay. Currents were observed within about two days of the hurricane passage and were dominated by a blue-shifted inertial ...
John A. Church; T. M. Joyce; James F. Price
Pulse-to-Pulse Coherent Doppler Measurements of Waves and Turbulence
This paper presents laboratory and field testing of a pulse-to-pulse coherent acoustic Doppler profiler for the measurement of turbulence in the ocean. In the laboratory, velocities and wavenumber spectra collected from Doppler and digital ...
Fabrice Veron; W. Kendall Melville
Doppler Sonar and Surface Waves: Range and Resolution
The performance limitations of an acoustic Doppler sonar system are explored and compared with anticipated requirements for the measurement of surface wave directional/frequency spectra. To obtain measurements to a range D requires a delay ?t ...
Jerome A. Smith
Chaos Theory Based Ultrasonic Doppler for Velocity Measurement of Fluid in the Petroleum Channel
In the ultrasonic Doppler flow measure method, Flow measurement is achieved by detecting the Doppler frequency shift of ultrasound during transmission in the fluid. However, the received acoustic signals are weak ones submerged in strong noise; for the ... Keywords: Chaos, Chaotic oscillator, Frequency shift, Ultrasonic Doppler
Tao Huang; Lele Qin
Doppler flowmeter
DOE Patents (OSTI)
A Doppler flowmeter impulses an ultrasonic fixed-frequency signal obliquely into a slurry flowing in a pipe and a reflected signal is detected after having been scattered off of the slurry particles, whereby the shift in frequencies between the signals is proportional to the slurry velocity and hence slurry flow rate. This flowmeter filters the Doppler frequency-shift signal, compares the filtered and unfiltered shift signals in a divider to obtain a ratio, and then further compares this ratio against a preset fractional ratio. The flowmeter utilizes a voltage-to-frequency convertor to generate a pulsed signal having a determinable rate of repetition precisely proportional to the divergence of the ratios. The pulsed signal serves as the input control for a frequency-controlled low-pass filter, which provides thereby that the cutoff frequency of the filtered signal is known. The flowmeter provides a feedback control by minimizing the divergence. With the cutoff frequency and preset fractional ratio known, the slurry velocity and hence flow will also be determinable.
Karplus, H.H.B.; Raptis, A.C.
Capability of Surface-Based Clear-Air Doppler Radar for Monitoring Meteorological Structure of Elevated Layers
Radars and acoustic sounding systems sense properties of the turbulence structure of the atmosphere. If atmospheric turbulence can be related to the mean gradient parameters, Doppler radars and acoustic sounders can provide information about ...
Earl E. Gossard; Russell B. Chadwick; Thomas R. Detman; John Gaynor
Multiyear Subinertial and Seasonal Eulerian Current Observations near the Florida Big Bend Coast
Multiyear in situ Eulerian acoustic Doppler current profiler measurements were obtained at 5-, 10-, and 19-m depths off the Big Bend coast, and in 19 m off the Florida Peninsula to the south. Analysis on subinertial time scales, dominated by ...
Ekaterina V. Maksimova; Allan J. Clarke
Virtual Doppler Lidar Instrument
Doppler lidars measure the range-resolved line-of-sight wind component by extracting the Doppler shift of radiation backscattered from atmospheric aerosols and molecules. A virtual instrument was developed to simulate wind measurements by flying ...
Ines Leike; Jürgen Streicher; Christian Werner; Viktor Banakh; Igor Smalikho; Werner Wergen; Alexander Cress
Damage inspection of fiber reinforced polymer-concrete systems using a distant acoustic-laser NDE technique
E-Print Network (OSTI)
In this paper, a distant acoustic-laser NDE technique is proposed, utilizing a high powered standoff parametric acoustic array (PAA) and laser Doppler vibrometry (LDV), for the detection of debonding and delamination in ...
Haupt, Robert W.
A Coherent Doppler Profiler for High-Resolution Particle Velocimetry in the Ocean: Laboratory Measurements of Turbulence and Particle Flux
A pulse-to-pulse coherent acoustic Doppler profiler has been developed for high-resolution particle velocimetry in the ocean, in particular for remote measurements of suspended sediment flux and turbulence in the nearshore and continental shelf ...
Len Zedel; Alex E. Hay
Doppler Lidar (DL) Handbook
SciTech Connect
The Doppler lidar (DL) is an active remote sensing instrument that provides range- and time-resolved measurements of radial velocity and attenuated backscatter. The principle of operation is similar to radar in that pulses of energy are transmitted into the atmosphere; the energy scattered back to the transceiver is collected and measured as a time-resolved signal. From the time delay between each outgoing transmitted pulse and the backscattered signal, the distance to the scatterer is inferred. The radial or line-of-sight velocity of the scatterers is determined from the Doppler frequency shift of the backscattered radiation. The DL uses a heterodyne detection technique in which the return signal is mixed with a reference laser beam (i.e., local oscillator) of known frequency. An onboard signal processing computer then determines the Doppler frequency shift from the spectra of the heterodyne signal. The energy content of the Doppler spectra can also be used to determine attenuated backscatter.
Newsom, RK
Acoustic Radar Studies of Rain Microphysics
Raindrop size distributions are obtained from the Doppler frequency spectrum of an acoustic radar. Number concentrations of 12 drop diameters with a minimum diameter 0.14 cm are obtained and averaged over 3–15 min at 20-m range gates from 20 to ...
S. G. Bradley
Receiver and Analog Homodyning Effects on Incoherent Doppler Velocity Estimates
Oceanic incoherent Doppler sonar systems (current profiling systems) employing intrapulse covariance calculations and related first spectral-moment approximations to calculate volumetric fluid motion are sensitive to design tolerance of the sonar ...
D. Scott Hansen
Acoustic telemetry.
Broadcasting messages through the earth is a daunting task. Indeed, broadcasting a normal telephone conversion through the earth by wireless means is impossible with todays technology. Most of us don't care, but some do. Industries that drill into the earth need wireless communication to broadcast navigation parameters. This allows them to steer their drill bits. They also need information about the natural formation that they are drilling. Measurements of parameters such as pressure, temperature, and gamma radiation levels can tell them if they have found a valuable resource such as a geothermal reservoir or a stratum bearing natural gas. Wireless communication methods are available to the drilling industry. Information is broadcast via either pressure waves in the drilling fluid or electromagnetic waves in the earth and well tubing. Data transmission can only travel one way at rates around a few baud. Given that normal Internet telephone modems operate near 20,000 baud, these data rates are truly very slow. Moreover, communication is often interrupted or permanently blocked by drilling conditions or natural formation properties. Here we describe a tool that communicates with stress waves traveling through the steel drill pipe and production tubing in the well. It's based on an old idea called Acoustic Telemetry. But what we present here is more than an idea. This tool exists, it's drilled several wells, and it works. Currently, it's the first and only acoustic telemetry tool that can withstand the drilling environment. It broadcasts one way over a limited range at much faster rates than existing methods, but we also know how build a system that can communicate both up and down wells of indefinite length.
Drumheller, Douglas Schaeffer; Kuszmaul, Scott S.
Method and apparatus for ultrasonic doppler velocimetry using speed of sound and reflection mode pulsed wideband doppler
According to the present invention, a method and apparatus rely upon tomographic measurement of the speed of sound and fluid velocity in a pipe. The invention provides a more accurate profile of velocity within flow fields where the speed of sound varies within the cross-section of the pipe. This profile is obtained by reconstruction of the velocity profile from the local speed of sound measurement simultaneously with the flow velocity. The method of the present invention is real-time tomographic ultrasonic Doppler velocimetry utilizing a to plurality of ultrasonic transmission and reflection measurements along two orthogonal sets of parallel acoustic lines-of-sight. The fluid velocity profile and the acoustic velocity profile are determined by iteration between determining a fluid velocity profile and measuring local acoustic velocity until convergence is reached.
Shekarriz, Alireza (Kennewick, WA); Sheen, David M. (Richland, WA)
Office of Legacy Management (LM)
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Current Shear–Inertial Wave Interaction in the Sargasso Sea
Acoustic Doppler profiler measurements of inertial waves embedded within the high shell region of a cold core ring in the Sargasso Sea are described. By repeatedly traversing the same point from different directions, a sampling pattern resembling ...
Richard P. Mied; Colin Y. Shen; Matthew J. Kidd
Waterspout Velocity Measurements by Airborne Doppler Lidar
A Doppler lidar measures the line-of-sight velocity of cloud droplets in a waterspout much as a meteorological Doppler radar measures the velocity of larger hydrometeors. We discuss details of the application of an airborne Doppler lidar to ...
R. L. Schwiesow; R. E. Cupp; P. C. Sinclair; R. F. Abbey Jr.
Doppler Radar Observations of Mammatus
Observations of mammatus-like cloud features associated with a convective rain shower were obtained using a vertically pointing 8-mm-wavelength Doppler radar. The radar's excellent sensitivity and resolution allowed even very weak, finescale ...
Brooks E. Martner
Field Measurements at River and Tidal Current Sites for Hydrokinetic Energy Development: Best Practices Manual
In this report, existing data collection techniques and protocols for characterizing open channel flows are reviewed and refined to further address the needs of the MHK industry. The report provides an overview of the hydrodynamics of river and tidal channels, and the working principles of modern acoustic instrumentation, including best practices in remote sensing methods that can be applied to hydrokinetic energy site characterization. Emphasis is placed upon acoustic Doppler velocimeter (ADV) and acoustic-Doppler current profiler (ADCP) instruments, as these represent the most practical and economical tools for use in the MHK industry. Incorporating the best practices as found in the literature, including the parameters to be measured, the instruments to be deployed, the instrument deployment strategy, and data post-processing techniques. The data collected from this procedure aims to inform the hydro-mechanical design of MHK systems with respect to energy generation and structural loading, as well as provide reference hydrodynamics for environmental impact studies. The standard metrics and protocols defined herein can be utilized to guide field experiments with MHK systems.
Neary, Vincent S [ORNL; Gunawan, Budi [Oak Ridge National Laboratory (ORNL)
Underwater Nonlinear Acoustic Speaker.
??In this work an acoustic parametric array for underwater use was designed, built and tested. An acoustic parametric array creates a focused beam of sound… (more)
Andersson, Sara
Doppler Radar Sampling Limitations in Convective Storms
Vertical air motion data from a T-28 aircraft were filtered and sampled to simulate Doppler radar measurements. The results suggest that multiple Doppler radar analyses are subject to potentially large spatial aliasing errors in deep convection ...
R. E. Carbone; M. J. Carpenter; C. D. Burghart
The Synthetic Dual-Doppler Analysis Technique
Synthetic dual-Doppler (SDD) is a single-Doppler analysis technique that combines measurements from two different times, provided the viewing angle changes significantly. In this study, the viability of the SDD technique is investigated through ...
Brian A. Klimowski; John D. Marwitz
Mapping of Airborne Doppler Radar Data
Two sets of equations are derived to 1) map airborne Doppler radar data from an aircraft-relative coordinate system to an earth-relative coordinate system, and 2) remove the platform motion from the observed Doppler velocities. These equations ...
Wen-Chau Lee; Peter Dodge; Frank D. Marks Jr.; Peter H. Hildebrand
Airborne Doppler Radar Data Analysis Workshop
The Airborne Doppler Radar Data Analysis Workshop, sponsored by the Atmospheric Technology Division (ATD) of the National Center for Atmospheric Research (NCAR), was the first to focus on analyzing airborne Doppler radar data. The workshop (held ...
Wen-Chau Lee; Frank D. Marks; Craig Walther
Simultaneous Velocity Ambiguity Resolution and Noise Suppression for Multifrequency Coherent Doppler Sonar
Coherent Doppler sonar is a useful tool for noninvasive measurement of ocean currents, sediment transport, and turbulence in coastal environments. Various methods have been proposed to separately address two of its inherent limitations: velocity ...
Jeremy Dillon; Len Zedel; Alex E. Hay
Acoustic transducer
An acoustic transducer is described comprising a one-piece hollow mandrel into the outer surface of which is formed a recess with sides perpendicular to the central axis of the mandrel and separated by a first distance and with a bottom parallel to the central axis and within which recess are a plurality of washer-shaped discs of a piezoelectric material and at least one disc of a temperature-compensating material with the discs being captured between the sides of the recess in a pre-stressed interference fit, typically at 2,000 psi of compressive stress. The transducer also includes a power supply and means to connect to a measurement device. The transducer is intended to be used for telemetry between a measurement device located downhole in an oil or gas well and the surface. The transducer is of an construction that is stronger with fewer joints that could leak fluids into the recess holding the piezoelectric elements than is found in previous acoustic transducers. 4 figs.
Drumheller, D.S.
An acoustic transducer comprising a one-piece hollow mandrel into the outer surface of which is formed a recess with sides perpendicular to the central axis of the mandrel and separated by a first distance and with a bottom parallel to the central axis and within which recess are a plurality of washer-shaped discs of a piezoelectric material and at least one disc of a temperature-compensating material with the discs being captured between the sides of the recess in a pre-stressed interference fit, typically at 2000 psi of compressive stress. The transducer also includes a power supply and means to connect to a measurement device. The transducer is intended to be used for telemetry between a measurement device located downhole in an oil or gas well and the surface. The transducer is of an construction that is stronger with fewer joints that could leak fluids into the recess holding the piezoelectric elements than is found in previous acoustic transducers.
Drumheller, Douglas S. (Cedar Crest, NM)
Acoustic cryocooler
An acoustic cryocooler with no moving parts is formed from a thermoacoustic driver (TAD) driving a pulse tube refrigerator (PTR) through a standing wave tube. Thermoacoustic elements in the TAD are spaced apart a distance effective to accommodate the increased thermal penetration length arising from the relatively low TAD operating frequency in the range of 15-60 Hz. At these low operating frequencies, a long tube is required to support the standing wave. The tube may be coiled to reduce the overall length of the cryocooler. One or two PTR's are located on the standing wave tube adjacent antinodes in the standing wave to be driven by the standing wave pressure oscillations. It is predicted that a heat input of 1000 W at 1000 K will maintain a cooling load of 5 W at 80 K. 3 figs.
Swift, G.W.; Martin, R.A.; Radebaugh, R.
An acoustic cryocooler with no moving parts is formed from a thermoacoustic driver (TAD) driving a pulse tube refrigerator (PTR) through a standing wave tube. Thermoacoustic elements in the TAD are spaced apart a distance effective to accommodate the increased thermal penetration length arising from the relatively low TAD operating frequency in the range of 15-60 Hz. At these low operating frequencies, a long tube is required to support the standing wave. The tube may be coiled to reduce the overall length of the cryocooler. One or two PTR's are located on the standing wave tube adjacent antinodes in the standing wave to be driven by the standing wave pressure oscillations. It is predicted that a heat input of 1000 W at 1000 K will maintian a cooling load of 5 W at 80 K.
Swift, Gregory W. (Santa Fe, NM); Martin, Richard A. (Los Alamos, NM); Radenbaugh, Ray (Louisville, CO)
Optimization of Concurrent Deployments of the Juvenile Salmon Acoustic Telemetry System and Other Hydroacoustic Equipment at John Day Dam
The purpose of this report is to document the results of the acoustic optimization study conducted at John Day Dam during January and February 2008. The goal of the study was to optimize performance of the Juvenile Salmon Acoustic Telemetry System (JSATS) by determining deployment and data acquisition methods to minimize electrical and acoustic interference from various other acoustic sampling devices. Thereby, this would allow concurrent sampling by active and passive acoustic methods during the formal evaluations of the prototype surface flow outlets at the dam during spring and summer outmigration seasons for juvenile salmonids. The objectives for the optimization study at John Day Dam were to: 1. Design and test prototypes and provide a total needs list of pipes and trolleys to deploy JSATS hydrophones on the forebay face of the powerhouse and spillway. 2. Assess the effect on mean percentage decoded of JSATS transmissions from tags arrayed in the forebay and detected on the hydrophones by comparing: turbine unit OFF vs. ON; spill bay OPEN vs. CLOSED; dual frequency identification sonar (DIDSON) and acoustic Doppler current profiler (ADCP) both OFF vs. ON at a spill bay; and, fixed-aspect hydroacoustic system OFF vs. ON at a turbine unit and a spill bay. 3. Determine the relationship between fixed-aspect hydroacoustic transmit level and mean percentage of JSATS transmissions decoded. The general approach was to use hydrophones to listen for transmissions from JSATS tags deployed in vertical arrays in a series perpendicular to the face of the dam. We used acoustic telemetry equipment manufactured by Technologic and Sonic Concepts. In addition, we assessed old and new JSATS signal detectors and decoders and two different types of hydrophone baffling. The optimization study consisted of a suite of off/on tests. The primary response variable was mean percentage of tag transmissions decoded. We found that there was no appreciable adverse effect on mean percentage decoded for JSATS transmitters from: turbine operations; spillway operations; DIDSON/ADCP acoustic energy; and PAS hydroacoustic systems at transmit level of -12 dB, although there was a significant impact at all higher transmit levels (-11 to -6 dB). The main conclusion from this optimization study is that valid JSATS telemetry data can be collected simultaneously with a DIDSON/ADCP and a PAS hydroacoustic system at transmit level -12 dB. Multiple evaluation tools should be considered to increase the robustness and thoroughness of future fish passage evaluations at John Day and other dams.
Ploskey, Gene R.; Hughes, James S.; Khan, Fenton; Kim, Jina; Lamarche, Brian L.; Johnson, Gary E.; Choi, Eric Y.; Faber, Derrek M.; Wilberding, Matthew C.; Deng, Zhiqun; Weiland, Mark A.; Zimmerman, Shon A.; Fischer, Eric S.; Cushing, Aaron W.
Moments of ambient Doppler spectra
The author studied the first four moments (center of mass, standard deviation, skew, and kurtosis) of the Doppler spectra in ambient regions of LLNL-Hughes real aperture radar data collected during WCSEX91--92. The goal was to correlate trends in the moments with wind velocity and direction. Although the center of mass appears to increase when the wind is blowing into the radar antenna, no other conclusions have been drawn from the higher order moments.
Lehman, S.K.
An Atmospheric Soliton Observed with Doppler Radar, Differential Absorption Lidar, and a Molecular Doppler Lidar
Airborne Leandre II differential absorption lidar (DIAL), S-band dual-polarization Doppler radar (S-Pol), and Goddard Lidar Observatory for Winds (GLOW) Doppler lidar data are used, in conjunction with surface mesonet and special sounding data, ...
Steven E. Koch; Cyrille Flamant; James W. Wilson; Bruce M. Gentry; Brian D. Jamison
Establishing a Conventional Doppler Sodar cum Doppler Minisodar at the National Physical Laboratory
A personal computer–based three-axis Doppler sodar, capable of working in Doppler minisodar mode too, has been established at the National Physical Laboratory, New Delhi, India. The fast Fourier transform technique has been used to extract the ...
B. S. Gera; S. P. Singal; Neeraj Saxena
Extended Overdetermined Dual-Doppler Formalism in Synthesizing Airborne Doppler Radar Data
During the intensive observing period of the field phase of the Coupled Ocean–Atmosphere Response Experiment (COARE) of the Tropical Oceans and Global Atmosphere (TOGA) program, airborne Doppler radars capable of fore–aft scanning (dual-Doppler ...
Michel Chong; Cláudia Campos
Comparison of Eddy Dissipation Rates from Spatial Spectra of Doppler Velocities and Doppler Spectrum Widths
Doppler radars offer unique data from which it is possible to estimate the turbulent eddy dissipation rates, ?. If the inertial subrange extends to lengths longer than the radar resolution volume size, ? can be obtained from the Doppler spectrum ...
Keith A. Brewster; Dusan S. Zrni?
Feasibility Test of an Airborne Pulse-Doppler Meteorological Radar
A vertically scanning, airborne, pulse-Doppler radar is described. Data processing methods to yield pseudo-dual-Doppler horizontal winds are presented. Results of an intercomparison with a ground-based dual-Doppler network are presented and ...
David P. Jorgensen; Peter H. Hildebrand; Charles L. Frush
Solid Rocket Motor Acoustic Testing
Acoustic data are often required for the determination of launch and powered flight loads for rocket systems and payloads. Such data are usually acquired during test firings of the solid rocket motors. In the current work, these data were obtained for two tests at a remote test facility where we were visitors. This paper describes the data acquisition and the requirements for working at a remote site, interfacing with the test hosts.
Rogers, J.D.
Quantum entanglement for acoustic spintronics
We consider the entanglement of spins for two electrons contributing to the acoustoelectric current driven by a surface acoustic wave (SAW) in two adjacent narrow channels by calculating their exchange energy (J). The channels belong to an acoustic nanocircuit which comprises a network of quasi-one-dimensional pinched-off channels serving as wires along which SAW quantum dots transport electrons. This is motivated by possible practical applications involving quantum information processing and quantum computers. We calculate J as a function of time as the electrons travel side-by-side in the adjacent channels and as a function of the distance between the centers of the channels. The leakage from the state in which the system is prepared, is calculated. The oscillations in the leakage indicate the probability for the electron system to make transitions between the ground and excited states, or for an electron to hop back and forth between channels.
Gumbs, Godfrey; Abranyos, Yonatan [Department of Physics and Astronomy, Hunter College of the City University of New York, 695 Park Avenue, New York, New York 10021 (United States)
Chromospheric Doppler Velocity Oscillations in a Sunspot
We analyse the chromospheric Doppler velocity oscillations in a sunspot using the high resolution spectral observations obtained from the Fast Imaging Solar Spectrograph(FISS) of the New Solar Telescope at the Big Bear Solar Observatory. The Doppler velocity maps are constructed from the bisectors of the spectral observations. The time series analysis of Doppler velocity maps show enhanced power in the sunspot umbra at higher frequencies and in the penumbra at lower frequencies. We find that the peak power frequency decreases gradually from the umbra to outward.
Maurya, R A
Acoustics by additive manufacturing.
??This study focuses on exploring the merging field of additive manufacturing and acoustics and introduces a new type of sound absorber which is regulating performance… (more)
Setaki, F.
Acoustic Microscopy Applications*
Figure: ...Fig. 17 A portion of the 160 mm 2 (0.25 in. 2 ) area of an alumina ceramic disk scanned by an acoustic microscope
Doppler Lidar Observations of a Downslope Windstorm
During January and February 1987, the NOAA/WPL pulsed Doppler lidar was deployed in the foothills west of Boulder, Colorado, to study orographically induced flows over the Continental Divide. On 29 January 1987, the lidar, with its unique spatial ...
Paul J. Neiman; R. M. Hardesty; M. A. Shapiro; R. E. Cupp
A Bistatic Multiple-Doppler Radar Network
A multiple-Doppler radar network can be constructed using only one, traditional, transmitting pencil-beam radar and one or more passive, low-gain, nontransmitting receivers at remote sites. Radiation scattered from the pencil beam of the ...
Joshua Wurman; Stanley Heckman; Dennis Boccippio
Operational Application of Meteorological Doppler Radar
Single Doppler weather radar velocity and reflectivity fields have been obtained with the National Center for Atmospheric Research (NCAR) 5 cm radars for a wide variety of weather situations. Among those weather features that can be identified by ...
James Wilson; Richard Carbone; Harold Baynton; Robert Serafin
Geostationary Doppler Radar and Tropical Cyclone Surveillance
The potential usefulness of spaceborne Doppler radar as a tropical cyclone observing tool is assessed by conducting a high-resolution simulation of an intense hurricane and generating synthetic observations of reflectivity and radial velocity. The ...
William E. Lewis; Eastwood Im; Simone Tanelli; Ziad Haddad; Gregory J. Tripoli; Eric A. Smith
An Autonomous Doppler Sodar Wind Profiling System
An autonomous Doppler sodar wind profiling system has been designed, built, tested, and then deployed for 2 years at a remote site in Coats Land, Antarctica. The system is designed around a commercially available phased-array sodar (a Scintec ...
Philip S. Anderson; Russell S. Ladkin; Ian A. Renfrew
Multiple-Doppler Radar Network Design
Observing programs utilizing Doppler radar must have them deployed in optimum locations to best satisfy experimental objectives and maximize economies. One wishes to determine the coordinate triples (xi, yi, zi), where i equals the number of ...
Peter S. Ray; Karen L. Sangren
Smoke-Column Observations from Two Forest Fires Using Doppler Lidar and Doppler Radar
To demonstrate the usefulness of active remote-sensing systems in observing forest fire plume behavior, we studied two fires, one using a 3.2-cm-wavelength Doppler radar, and one more extensively, using Doppler lidar. Both instruments observed ...
R. M. Banta; L. D. Olivier; E. T. Holloway; R. A. Kropfli; B. W. Bartram; R. E. Cupp; M. J. Post
Evaluation of Meteorological Airborne Doppler Radar. Part II: Triple-Doppler Analyses of Air Motions
This is Part II of a paper dealing with the capabilities and use of airborne Doppler radar to observe motions within storms. Part I deals with dual-Doppler analyses of convective storm structure, using airborne and combinations of airborne and ...
Cynthia K. Mueller; Peter H. Hildebrand
Acoustic cooling engine
An acoustic cooling engine with improved thermal performance and reduced internal losses comprises a compressible fluid contained in a resonant pressure vessel. The fluid has a substantial thermal expansion coefficient and is capable of supporting an acoustic standing wave. A thermodynamic element has first and second ends and is located in the resonant pressure vessel in thermal communication with the fluid. The thermal response of the thermodynamic element to the acoustic standing wave pumps heat from the second end to the first end. The thermodynamic element permits substantial flow of the fluid through the thermodynamic element. An acoustic driver cyclically drives the fluid with an acoustic standing wave. The driver is at a location of maximum acoustic impedance in the resonant pressure vessel and proximate the first end of the thermodynamic element. A hot heat exchanger is adjacent to and in thermal communication with the first end of the thermodynamic element. The hot heat exchanger conducts heat from the first end to portions of the resonant pressure vessel proximate the hot heat exchanger. The hot heat exchanger permits substantial flow of the fluid through the hot heat exchanger. The resonant pressure vessel can include a housing less than one quarter wavelength in length coupled to a reservoir. The housing can include a reduced diameter portion communicating with the reservoir. The frequency of the acoustic driver can be continuously controlled so as to maintain resonance.
Hofler, Thomas J. (Los Alamos, NM); Wheatley, John C. (Los Alamos, NM); Swift, Gregory W. (Santa Fe, NM); Migliori, Albert (Santa Fe, NM)
Acoustical heat pumping engine
The disclosure is directed to an acoustical heat pumping engine without moving seals. A tubular housing holds a compressible fluid capable of supporting an acoustical standing wave. An acoustical driver is disposed at one end of the housing and the other end is capped. A second thermodynamic medium is disposed in the housing near to but spaced from the capped end. Heat is pumped along the second thermodynamic medium toward the capped end as a consequence both of the pressure oscillation due to the driver and imperfect thermal contact between the fluid and the second thermodynamic medium. 2 figs.
Wheatley, J.C.; Swift, G.W.; Migliori, A.
The disclosure is directed to an acoustical heat pumping engine without moving seals. A tubular housing holds a compressible fluid capable of supporting an acoustical standing wave. An acoustical driver is disposed at one end of the housing and the other end is capped. A second thermodynamic medium is disposed in the housing near to but spaced from the capped end. Heat is pumped along the second thermodynamic medium toward the capped end as a consequence both of the pressure oscillation due to the driver and imperfect thermal contact between the fluid and the second thermodynamic medium.
Wheatley, John C. (Los Alamos, NM); Swift, Gregory W. (Los Alamos, NM); Migliori, Albert (Santa Fe, NM)
Acoustic well cleaner
A method and apparatus are disclosed for cleaning the wellbore and the near wellbore region. A sonde is provided which is adapted to be lowered into a borehole and which includes a plurality of acoustic transducers arranged around the sonde. Electrical power provided by a cable is converted to acoustic energy. The high intensity acoustic energy directed to the borehole wall and into the near wellbore region, redissolves or resuspends the material which is reducing the permeability of the formation and/or restricting flow in the wellbore.
Maki, Jr., Voldi E. (11904 Bell Ave., Austin, TX 78759-2415); Sharma, Mukul M. (Dept. of Petroleum Engr. Univ. of Texas, Austin, TX 78712)
Compact acoustic refrigerator
A compact acoustic refrigeration system actively cools components, e.g., electrical circuits, in a borehole environment. An acoustic engine includes first thermodynamic elements for generating a standing acoustic wave in a selected medium. An acoustic refrigerator includes second thermodynamic elements located in the standing wave for generating a relatively cold temperature at a first end of the second thermodynamic elements and a relatively hot temperature at a second end of the second thermodynamic elements. A resonator volume cooperates with the first and second thermodynamic elements to support the standing wave. To accommodate the high heat fluxes required for heat transfer to/from the first and second thermodynamic elements, first heat pipes transfer heat from the heat load to the second thermodynamic elements and second heat pipes transfer heat from first and second thermodynamic elements to the borehole environment. 18 figs.
Bennett, G.A.
Space, time and acoustics
This thesis describes the development of new concepts in acoustical analysis from their inception to implementation as a computer design tool. Research is focused on a computer program which aids the designer to visually ...
Thompson, Philip R. Z. (Philip Reed Zane)
Acoustic imaging system
An acoustic imaging system for displaying an object viewed by a moving array of transducers as the array is pivoted about a fixed point within a given plane. A plurality of transducers are fixedly positioned and equally spaced within a laterally extending array and operatively directed to transmit and receive acoustic signals along substantially parallel transmission paths. The transducers are sequentially activated along the array to transmit and receive acoustic signals according to a preestablished sequence. Means are provided for generating output voltages for each reception of an acoustic signal, corresponding to the coordinate position of the object viewed as the array is pivoted. Receptions from each of the transducers are presented on the same display at coordinates corresponding to the actual position of the object viewed to form a plane view of the object scanned.
Smith, Richard W. (Richland, WA)
Atmospheric Acoustic Minisounder
An improved version of a monostatic acoustic minisounder for the investigation of the structure and dynamics of the lower boundary layer, operating at high frequencies and equipped with a specially designed micro-antenna and advanced electronic ...
D. N. Asimakopoulos; C. G. Helmis; G. J. Stephanou
A compact acoustic refrigeration system actively cools components, e.g., electrical circuits (22), in a borehole environment. An acoustic engine (12, 14) includes first thermodynamic elements (12) for generating a standing acoustic wave in a selected medium. An acoustic refrigerator (16, 26, 28) includes second thermodynamic elements (16) located in the standing wave for generating a relatively cold temperature at a first end of the second thermodynamic elements (16) and a relatively hot temperature at a second end of the second thermodynamic elements (16). A resonator volume (18) cooperates with the first and second thermodynamic elements (12, 16) to support the standing wave. To accommodate the high heat fluxes required for heat transfer to/from the first and second thermodynamic elements (12, 16), first heat pipes (24, 26) transfer heat from the heat load (22) to the second thermodynamic elements (16) and second heat pipes (28, 32) transfer heat from first and second thermodynamic elements (12, 16) to the borehole environment.
Bennett, Gloria A. (Los Alamos, NM)
Spacetime transformation acoustics
A recently proposed analogue transformation method has allowed the extension of transformation acoustics to general spacetime transformations. We analyze here in detail the differences between this new analogue transformation acoustics (ATA) method and the standard one (STA). We show explicitly that STA is not suitable for transformations that mix space and time. ATA takes as starting point the acoustic equation for the velocity potential, instead of that for the pressure as in STA. This velocity-potential equation by itself already allows for some transformations mixing space and time, but not all of them. We explicitly obtain the entire set of transformations that do not leave its form invariant. It is in these cases that ATA shows its true potential, allowing for building a transformation acoustics method that enables the full range of spacetime transformations. We provide an example of an important transformation which cannot be achieved with STA. Using this transformation, we design and simulate an acous...
García-Meca, C; Barceló, C; Jannes, G; Sánchez-Dehesa, J; Martínez, A
Automatic acoustic guitar tuner
Acoustic guitar musicians tune their instruments by using a conventional tuner. Individuals pluck the string and the conventional tuner indicates whether the note is sharp or flat. The musician then has to wind the string ...
Bocanegra, Alfredo
This invention is comprised of a compact acoustic refrigeration system that actively cools components, e.g., electrical circuits, in a borehole environment. An acoustic engine includes first thermodynamic elements for generating a standing acoustic wave in a selected medium. An acoustic refrigerator includes second thermodynamic elements located in the standing wave for generating a relatively cold temperature at a first end of the second thermodynamic elements and a relatively hot temperature at a second end of the second thermodynamic elements. A resonator volume cooperates with the first and second thermodynamic elements to support the standing wave. To accommodate the high heat fluxes required for heat transfer to/from the first and second thermodynamic elements, first heat pipes transfer heat from the heat load to the second thermodynamic elements and second heat pipes transfer heat from first and second thermodynamic elements to the borehole environment.
Keyboard acoustic emanations revisited
We examine the problem of keyboard acoustic emanations. We present a novel attack taking as input a 10-minute sound recording of a user typing English text using a keyboard, and then recovering up to 96% of typed characters. There is no need for a labeled ... Keywords: HMM, acoustic emanations, cepstrum, computer security, electronic eavesdropping, hidden Markov models, human factors, keyboards, learning theory, privacy, signal analysis
Li Zhuang; Feng Zhou; J. D. Tygar
We examine the problem of keyboard acoustic emanations. We present a novel attack taking as input a 10-minute sound recording of a user typing English text using a keyboard and recovering up to 96% of typed characters. There is no need for training ... Keywords: Computer security, HMM, acoustic manations, cepstrum, electronic eavesdropping, hidden markov models, human factors, keyboards, learning theory, privacy, signal analysis
Laser Doppler Velocimeter particle velocity measurement system
This report gives a detailed description of the operation of the Laser Doppler Velocimeter (LDV) system maintained by DIAL at MSU. LDV is used for the measurement of flow velocities and turbulence levels in various fluid flow settings. Ills report details the operation and maintenance of the LDV system and provides a first-time user with pertinent information regarding the system`s setup for a particular application. Particular attention has been given to the use of the Doppler signal analyzer (DSA) and the burst spectrum analyzer (BSA) signal processors and data analysis.
Wilson, W.W.; Srikantaiah, D.V.; Philip, T.; George, A.
A 94-GHz Doppler Radar for Cloud Observations
A Doppler radar operating at 3.2 mm wavelength was designed and assembled primarily for observation of clouds and precipitation. Phase detection of the radar signals which is required for Doppler operation is implemented through the use of a ...
Roger Lhermitte
Efficient Dealiasing of Doppler Velocities Using Local Environment Constraints
A Doppler velocity dealiasing algorithm is described that processes one radial at a time by comparing that radial with a previous radial. This technique has worked reliably on numerous Doppler radar datasets for clear air, thunderstorm, and ...
Michael D. Eilts; Steven D. Smith
A New Relationship between Mean Doppler Velocity and Differential Reflectivity
A new relationship has been established linking the vertical mean Doppler velocity of raindrop spectra and the accompanying differential reflectivities. It is based upon the specific radar combination of a vertically pointing Doppler and a ...
Matthias Steiner
Measurement of Raindrop Size Distributions Using a Small Doppler Radar
A small X-band bistatic Doppler radar originally developed for use in automated weather stations as a Precipitation Occurrence Sensor System (POSS) can also measure real time raindrop size distributions. In contrast to large-scale pulsed Doppler ...
Brian E. Sheppard
Doppler cooling to the Quantum limit M. Chalony,1
atom is cooled because of the difference in absorption probabilities, induced by the Doppler effectDoppler cooling to the Quantum limit M. Chalony,1 A. Kastberg,2 B. Klappauf,3 and D. Wilkowski1, 4: July 12, 2011) Doppler cooling on a narrow transition is limited by the noise of single scattering
A Wavelet-Based Ammunition Doppler Radar System
Today's state-of-the-art ammunition Doppler radars use the Fourier spectrogram for the joint time-frequency analysis of ammunition Doppler signals. In this paper, we implement the joint time-frequency analysis of ammunition Doppler signals based on the ...
S. H. Ong; Abbas Z. Kouzani
Dual-Doppler and Single-Doppler Analysis of a Tornadic Storm Undergoing Mergers and Repeated Tornadogenesis
Dual-Doppler observations with unprecedented finescale spatial and temporal resolution are used to characterize the vector wind field in and near a tornado occurring near Kiefer, Oklahoma, on 26 May 1997. Analyses of the dual-Doppler vector wind ...
Joshua Wurman; Yvette Richardson; Curtis Alexander; Stephen Weygandt; Peng Fei Zhang
Airborne Doppler Lidar Wind Field Measurements
A coherent Doppler lidar has been used in an aircraft to measure the 2-dimensional wind field in a number of different atmospheric situations. The lidar, a pulsed CO2 system, was installed in the NASA Convair 990. Galileo II, and flown in a ...
J. Bilbro; G. Fichtl; D. Fitzjarrald; M. Krause; R. Lee
LLNL-TR-534931 Doppler Broadening Update
LLNL-TR-534931 Doppler Broadening Update: Broadening near the Unresolved Resonance Region.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. #12;3 LLNL version of this paper: John Scorby (LLNL), Robert MacFarlane (LANL), Maurice Greene (ORNL), S. Ganesan
Cullen, Red
Acoustical properties of drill strings
The recovery of petrochemical and geothermal resources requires extensive drilling of wells to increasingly greater depths. Real-time collection and telemetry of data about the drilling process while it occurs thousands of feet below the surface is an effective way of improving the efficiency of drilling operations. Unfortunately, due to hostile down-hole environments, telemetry of this data is an extremely difficult problem. Currently, commercial systems transmit data to the surface by producing pressure pulses within the portion of the drilling mud enclosed in the hollow steel drill string. Transmission rates are between two and four data bits per second. Any system capable of raising data rates without increasing the complexity of the drilling process will have significant economic impact. One alternative system is based upon acoustical carrier waves generated within the drill string itself. If developed, this method would accommodate data rates up to 100 bits per second. Unfortunately, the drill string is a periodic structure of pipe and threaded tool joints, the transmission characteristics are very complex and exhibit a banded and dispersive structure. Over the past forty years, attempts to field systems based upon this transmission method have resulted in little success. This paper examines this acoustical transmission problem in great detail. The basic principles of acoustic wave propagation in the periodic structure of the drill string are examined through theory, laboratory experiment, and field test. The results indicate the existence of frequency bands which are virtually free of attenuation and suitable for data transmission at high bit rates. 9 refs., 38 figs., 2 tabs.
In eclipsing binaries the stellar rotation of the two components will cause a rotational Doppler beaming during eclipse ingress and egress when only part of the eclipsed component is covered. For eclipsing binaries with fast spinning components this photometric analog of the well-known spectroscopic Rossiter-McLaughlin effect can exceed the strength of the orbital effect. Example light curves are shown for a detached double white dwarf binary, a massive O-star binary and a transiting exoplanet case, similar to WASP-33b. Inclusion of the rotational Doppler beaming in eclipsing systems is a prerequisite for deriving the correct stellar parameters from fitting high-quality photometric light curves and can be used to determine stellar obliquities as well as, e.g., an independent measure of the rotational velocity in those systems that may be expected to be fully synchronized.
Groot, Paul J., E-mail: email@example.com [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States)
Doppler cooling three-electronic-level molecules
Analogous to the extension of laser cooling techniques from two-level to three-level atoms, Doppler cooling of molecules with an intermediate electronic state is considered. In particular, we use a rate-equation approach to simulate cooling of SiO+, in which population buildup in the intermediate state is prevented by its short lifetime. We determine that Doppler cooling of SiO+ can be accomplished without optically repumping from the intermediate state, at the cost of causing undesirable parity flips and rotational diffusion. Since the necessary repumping would require a large number of continuous-wave lasers, optical pulse shaping of a femtosecond laser is proposed as an attractive alternative. Other candidate three-electron-level molecules are also discussed.
Nguyen, J H V
Photonic Doppler Velocimetry Multiplexing Techniques: Evaluation of Photonic Techniques
This poster reports progress related to photonic technologies. Specifically, the authors developed diagnostic system architecture for a Multiplexed Photonic Doppler Velocimetry (MPDV) that incorporates frequency and time-division multiplexing into existing PDV methodology to provide increased channel count. Current MPDV design increases number of data records per digitizer channel 8x, and also operates as a laser-safe (Class 3a) system. Further, they applied heterodyne interferometry to allow for direction-of-travel determination and enable high-velocity measurements (>10 km/s) via optical downshifting. They also leveraged commercially available, inexpensive and robust components originally developed for telecom applications. Proposed MPDV architectures employ only commercially available, fiber-coupled hardware.
Edward Daykin
Acoustic Imaging Suite
INL's acoustic imaging technology improves methods of capturing moving images of a specified object by using a photorefractive effect to produce a full-field image of the object without using a probe to perform a full scan of the object. INL ...
Upstream Measurements of Wind Profiles with Doppler Lidar for Improved Wind Energy Integration
New upstream measurements of wind profiles over the altitude range of wind turbines will be produced using a scanning Doppler lidar. These long range high quality measurements will provide improved wind power forecasts for wind energy integration into the power grid. The main goal of the project is to develop the optimal Doppler lidar operating parameters and data processing algorithms for improved wind energy integration by enhancing the wind power forecasts in the 30 to 60 minute time frame, especially for the large wind power ramps. Currently, there is very little upstream data at large wind farms, especially accurate wind profiles over the full height of the turbine blades. The potential of scanning Doppler lidar will be determined by rigorous computer modeling and evaluation of actual Doppler lidar data from the WindTracer system produced by Lockheed Martin Coherent Technologies, Inc. of Louisville, Colorado. Various data products will be investigated for input into numerical weather prediction models and statistically based nowcasting algorithms. Successful implementation of the proposed research will provide the required information for a full cost benefit analysis of the improved forecasts of wind power for energy integration as well as the added benefit of high quality wind and turbulence information for optimal control of the wind turbines at large wind farms.
Rodney Frehlich
Modelling Solar Oscillation Power Spectra: II. Parametric Model of Spectral Lines Observed in Doppler Velocity Measurements
We describe a global parametric model for the observed power spectra of solar oscillations of intermediate and low degree. A physically motivated parameterization is used as a substitute for a direct description of mode excitation and damping as these mechanisms remain poorly understood. The model is targeted at the accurate fitting of power spectra coming from Doppler velocity measurements and uses an adaptive response function that accounts for both the vertical and horizontal components of the velocity field on the solar surface and for possible instrumental and observational distortions. The model is continuous in frequency, can easily be adapted to intensity measurements and extends naturally to the analysis of high-frequency pseudo modes (interference peaks at frequencies above the atmospheric acoustic cutoff).
Vorontsov, Sergei V
The Surface Expression of Semidiurnal Internal Tides near a Strong Source at Hawaii. Part I: Observations and Numerical Predictions
Observations of semidiurnal currents from high-frequency radio Doppler current meters and moored acoustic Doppler current profilers (ADCPs) in the Kauai Channel, Hawaii, are described and compared with two primitive equation numerical models of ...
C. Chavanne; P. Flament; G. Carter; M. Merrifield; D. Luther; E. Zaron; K-W. Gurgel
Acoustic paramagnetic logging tool
New methods and apparatus are disclosed which allow measurement of the presence of oil and water in geological formations using a new physical effect called the Acoustic Paramagnetic Logging Effect (APLE). The presence of petroleum in formation causes a slight increase in the earth's magnetic field in the vicinity of the reservoir. This is the phenomena of paramagnetism. Application of an acoustic source to a geological formation at the Larmor frequency of the nucleons present causes the paramagnetism of the formation to disappear. This results in a decrease in the earth3 s magnetic field in the vicinity of the oil bearing formation. Repetitively frequency sweeping the acoustic source through the Larmor frequency of the nucleons present (approx. 2 kHz) causes an amplitude modulation of the earth's magnetic field which is a consequence of the APLE. The amplitude modulation of the earth's magnetic field is measured with an induction coil gradiometer and provides a direct measure of the amount of oil and water in the excitation zone of the formation . The phase of the signal is used to infer the longitudinal relaxation times of the fluids present, which results in the ability in general to separate oil and water and to measure the viscosity of the oil present. Such measurements may be preformed in open boreholes and in cased well bores.
Vail, III, William B. (Bothell, WA)
Cylindrical Acoustic Levitator/Concentrator
NLE Websites -- All DOE Office Websites (Extended Search)
Cylindrical Acoustic Levitator/Concentrator Cylindrical Acoustic Levitator/Concentrator Cylindrical Acoustic Levitator/Concentrator A low-power, inexpensive acoustic apparatus for levitation and/or concentration of aerosols and small liquid/solid samples having particulates up to several millimeters in diameter in air or other fluids is described. Available for thumbnail of Feynman Center (505) 665-9090 Email Cylindrical Acoustic Levitator/Concentrator A low-power, inexpensive acoustic apparatus for levitation and/or concentration of aerosols and small liquid/solid samples having particulates up to several millimeters in diameter in air or other fluids is described. It is constructed from a commercially available, hollow cylindrical piezoelectric crystal which has been modified to tune the resonance frequency of the breathing mode resonance of the crystal to that
Multipurpose Acoustic Sensor for Downhole Fluid Monitoring
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.
Pantea, Cristian [Los Alamos National Laboratory
Elastic parabolic equation solutions for underwater acoustic problems using seismic sources
Elastic parabolic equation solutions for underwater acoustic problems using seismic sources Scott D theoretic methods, and attempts to model them with fluid-bottom parabolic equation solu- tions suggest between elastic and acoustic waves, current elastic parabolic equation solutions must be modified to allow
Acoustic Enhancement of Photodetecting Devices
for suspect materials, to advanced weapons guidance. Using a high Q acoustic resonator, the invention increases the sensitivity of the detectors by an order of
A low-power, inexpensive acoustic apparatus for levitation andor concentration of aerosols and small liquidsolid samples having particulates up to several millimeters in...
Acoustic Character Of Hydraulic Fractures In Granite
Hydraulic fractures in homogeneous granitic rocks were logged with conventional acoustic-transit-time, acoustic-waveform, and acoustic-televiewer logging systems. Fractured intervals ranged in depth from 45 to 570m. and ...
Paillet, Frederick I.
Scopes and Challenges of Dual-Doppler Lidar Wind Measurements—An Error Analysis
Pulsed Doppler lidars are powerful tools for long-range high-resolution measurements of radial wind velocities. With the development of commercial Doppler lidars and the reduction of acquisition costs, dual-Doppler lidar systems will be become ...
Christina Stawiarski; Katja Träumner; Christoph Knigge; Ronald Calhoun
Observations of Two Colorado Thunderstorms by Means of a Zenith-Pointing Doppler Radar
A description is given of the distributions of radar reflectivity, mean Doppler velocity, vertical air velocity and Doppler-velocity variance in two thunderstorms over eastern Colorado. A zenith-pointing Doppler radar was used to obtain data at ...
Louis J. Battan
Dealiasing Doppler Velocities Measured by a Bistatic Radar Network during a Downburst-Producing Thunderstorm
The object of this paper was to develop an automated dealiasing scheme that dealiases Doppler velocities measured by a bistatic Doppler radar network. The particular network consists of the C-band polarimetric diversity Doppler radar, POLDIRAD, ...
Katja Friedrich; Olivier Caumont
Pulsed Doppler lidars are powerful tools for long-range, high-resolution measurements of radial wind velocities. With the development of commercial Doppler lidars and the reduction of acquisition costs, dual-Doppler lidar systems will be become ...
Low probability of detection underwater acoustic ...
... increases significantly the data processing load. B. Temporal coherence: Signal coherence time The Doppler corrected impulse responses are ...
Building Energy Software Tools Directory: Acoustics Program
Acoustics Program Developed to help designers accurately model the sound level reaching building tenant's ears, the Trane Acoustics Program (TAP) "projects" equipment sound power...
Transcranial Doppler: A Tool for Augmented Cognition in Virtual Environments
In this work, we propose the use of Transcranial Doppler Monitoring (TCD) as a tool to measure brain activity during the exposure to virtual environments (VE) that can be used in Augmented Cognition (AugCog) systems. The technique is non-invasive, and ... Keywords: Augmented Cognition, Cognitive State Assessment, Neurophysiological Data, Transcranial Doppler, Virtual Reality
Beatriz Rey; Mariano Alcańiz; Valery Naranjo; Jose Tembl; Vera Parkhutik
Mixed-Phase Cloud Retrievals Using Doppler Radar Spectra
Mixed-Phase Cloud Retrievals Using Mixed-Phase Cloud Retrievals Using Doppler Radar Spectra M. D. Shupe, S. Y. Matrosov, and T. L. Schneider National Oceanic and Atmospheric Administration Environmental Technology Laboratory Boulder, Colorado P. Kollias Rosentiel School of Marine Atmospheric Sciences University of Miami Miami, Florida Introduction The radar Doppler spectrum contains a wealth of information on cloud microphysical properties. Typically, radar-based cloud retrievals use only the zeroth or first moments of the Doppler spectrum - reflectivity and mean Doppler velocity - to derive quantities such as cloud water content and particle characteristic size (e.g., Liou and Sassen 1994; Matrosov et al. 2002). When using only the moments of the Doppler spectrum, important spectral information can be lost, particularly when the spectrum is
The electron geodesic acoustic mode
In this report, a novel new mode, named the electron geodesic acoustic mode, is presented. This mode can occur in toroidal plasmas like the conventional geodesic acoustic mode (GAM). The frequency of this new mode is much larger than that of the conventional GAM by a factor equal to the square root of the ion to electron mass ratio.
Chakrabarti, N. [Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Calcutta 700 064 (India); Guzdar, P. N. [Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742 (United States); Kaw, P. K. [Institute for Plasma Research Bhat, Gandhinagar 382428 (India)
Acoustics sound systems for baseball
Acoustic considerations impact the design of sound systems for baseball stadiums in several important ways. Intrusion by the sound system into adjacent residential communities must often be minimized. Excess attenuation greatly increases the required high frequency component of acoustic power for sound travelling long distances
Opto-acoustic thrombolysis
This invention is a catheter-based device for generating an ultrasound excitation in biological tissue. Pulsed laser light is guided through an optical fiber to provide the energy for producing the acoustic vibrations. The optical energy is deposited in a water-based absorbing fluid, e.g. saline, thrombolytic agent, blood or thrombus, and generates an acoustic impulse in the fluid through thermoelastic and/or thermodynamic mechanisms. By pulsing the laser at a repetition rate (which may vary from 10 Hz to 100 kHz) an ultrasonic radiation field can be established locally in the medium. This method of producing ultrasonic vibrations can be used in vivo for the treatment of stroke-related conditions in humans, particularly for dissolving thrombus or treating vasospasm. The catheter can also incorporate thrombolytic drug treatments as an adjunct therapy and it can be operated in conjunction with ultrasonic detection equipment for imaging and feedback control and with optical sensors for characterization of thrombus type and consistency.
Celliers, Peter (Berkeley, CA); Da Silva, Luiz (Danville, CA); Glinsky, Michael (Livermore, CA); London, Richard (Orinda, CA); Maitland, Duncan (Livermore, CA); Matthews, Dennis (Moss Beach, CA); Fitch, Pat (Livermore, CA)
Celliers, P.; Silva, L. Da; Glinsky, M.; London, R.; Maitland, D.; Matthews, D.; Fitch, P.
Design and analysis of a high-rate acoustic link for underwater video transmission
A high bit rate acoustic link for underwater video transmission is examined. Currently, encoding standards support video transmission at bit rates as low as 64 kbps. While this rate is still above the limit of commercially ...
Pelekanakis, Konstantinos
K-distribution fading models for Bayesian estimation of an underwater acoustic channel
Current underwater acoustic channel estimation techniques generally apply linear MMSE estimation. This approach is optimal in a mean square error sense under the assumption that the impulse response fluctuations are well ...
Laferriere, Alison Beth
Estimation of radial acoustic wave propagation in relative motion
Sound emission and propagation through the moving air in front of aircraft compressors and behind the turbine assemblies is investigated at UPB in a current research program. Results of the sound waves radial propagation in the first stage of the low ... Keywords: acoustics, finite volumes method, relative fluid mechanics, sound pressure level, sound propagation, sound waves, wave modeling
Alina Bogoi; Radu D. Rugescu
Acoustic Inspection Devices: Detecting the Undetectable
Acoustic Inspection Devices: Detecting the Undetectable Emerging homeland security threats and increasingly sophisticated adversaries have heightened ...
NW-MILO Acoustic Data Collection
There is an enduring requirement to improve our ability to detect potential threats and discriminate these from the legitimate commercial and recreational activity ongoing in the nearshore/littoral portion of the maritime domain. The Northwest Maritime Information and Littoral Operations (NW-MILO) Program at PNNL's Coastal Security Institute in Sequim, Washington is establishing a methodology to detect and classify these threats - in part through developing a better understanding of acoustic signatures in a near-shore environment. The purpose of the acoustic data collection described here is to investigate the acoustic signatures of small vessels. The data is being recorded continuously, 24 hours a day, along with radar track data and imagery. The recording began in August 2008, and to date the data contains tens of thousands of signals from small vessels recorded in a variety of environmental conditions. The quantity and variety of this data collection, with the supporting imagery and radar track data, makes it particularly useful for the development of robust acoustic signature models and advanced algorithms for signal classification and information extraction. The underwater acoustic sensing system is part of a multi-modal sensing system that is operating near the mouth of Sequim Bay. Sequim Bay opens onto the Straight of Juan de Fuca, which contains part of the border between the U.S. and Canada. Table 1 lists the specific components used for the NW-MILO system. The acoustic sensor is a hydrophone permanently deployed at a mean depth of about 3 meters. In addition to a hydrophone, the other sensors in the system are a marine radar, an electro-optical (EO) camera and an infra-red (IR) camera. The radar is integrated with a vessel tracking system (VTS) that provides position, speed and heading information. The data from all the sensors is recorded and saved to a central server. The data has been validated in terms of its usability for characterizing the signatures of small vessels. The sampling rate of 8 kHz and low pass filtering to 2 kHz results in an alias-free signal in the frequency band that is appropriate for small vessels. Calibration was performed using a Lubell underwater speaker so that the raw data signal levels can be converted to sound pressure. Background noise is present due to a nearby pump and as a result of tidal currents. More study is needed to fully characterize the noise, but it does not pose an obstacle to using the acoustic data for the purposes of vessel detection and signature analysis. The detection range for a small vessel was estimated using the calibrated voltage response of the system and a cylindrical spreading model for transmission loss. The sound pressure of a typical vessel with an outboard motor was found to be around 140 dB mPa, and could theoretically be detected from 10 km away. In practical terms, a small vessel could reliably be detected from 3 - 5 km away. The data is archived in netCDF files, a standard scientific file format that is "self describing". This means that each data file contains the metadata - timestamps, units, origin, etc. - needed to make the data meaningful and portable. Other file formats, such as XML, are also supported. A visualization tool has been developed to view the acoustic data in the form of spectrograms, along with the coincident radar track data and camera images.
Matzner, Shari; Myers, Joshua R.; Maxwell, Adam R.; Jones, Mark E.
Acoustical heat-pumping engine
Iterative equalization and decoding applied to underwater acoustic communication
1.1 Shallow Underwater Acoustic Channels . . . . . . . .and Decoding Approach for Underwater Acoustic Commu-Equalization and Decoding of Underwater Acoustic Using Array
Sifferlen, James F.
Employing the complete acoustical palette in teleconferencing design
The prevailing architectural acoustics approach in teleconferencing is "Deader is better" or "No acoustics is better than bad acoustics." In some situations
Peter D'Antonio
Microsoft Word - Acoustic Sensor for Pipeline Monitoring_Revised.do
LA-UR-05-6025 LA-UR-05-6025 Approved for public release; distribution is unlimited. Title: Acoustic Sensor for Pipeline Monitoring: Technology Report Author(s): Dipen N. Sinha Submitted to: Gas Technology Management Division Strategic Center for Natural Gas and Oil National Energy Technology Laboratory 2 Acoustic Sensor for Pipeline Monitoring: Technology Report Dipen Sinha Los Alamos National Laboratory July 20, 2005 Executive Summary This report presents detailed information on the effort to develop acoustic sensing technologies for natural gas pipe line monitoring. It starts with a historical evolution of the project and ends with the current status. The various technical accomplishments during this effort are pointed out. The latest technique involves the use of Lamb wave propagation in the wall of a pipe generated in a stand-off manner for defect detection. The report presents
Acoustically Enhanced Boiling Heat Transfer
An acoustic field is used to increase the critical heat flux (CHF) of a flat-boiling-heat-transfer surface. The increase is a result of the acoustic effects on the vapor bubbles. Experiments are performed to explore the effects of an acoustic field on vapor bubbles in the vicinity of a rigid-heated wall. Work includes the construction of a novel heater used to produce a single vapor bubble of a prescribed size and at a prescribed location on a flatboiling surface for better study of an individual vapor bubble's reaction to the acoustic field. Work also includes application of the results from the single-bubble heater to a calibrated-copper heater used for quantifying the improvements in CHF.
Z. W. Douglas; M. K. Smith; A. Glezer
Acoustic Characterization of Mesoscale Objects
This report describes the science and engineering performed to provide state-of-the-art acoustic capabilities for nondestructively characterizing mesoscale (millimeter-sized) objects--allowing micrometer resolution over the objects entire volume. Materials and structures used in mesoscale objects necessitate the use of (1) GHz acoustic frequencies and (2) non-contacting laser generation and detection of acoustic waves. This effort demonstrated that acoustic methods at gigahertz frequencies have the necessary penetration depth and spatial resolution to effectively detect density discontinuities, gaps, and delaminations. A prototype laser-based ultrasonic system was designed and built. The system uses a micro-chip laser for excitation of broadband ultrasonic waves with frequency components reaching 1.0 GHz, and a path-stabilized Michelson interferometer for detection. The proof-of-concept for mesoscale characterization is demonstrated by imaging a micro-fabricated etched pattern in a 70 {micro}m thick silicon wafer.
Chinn, D; Huber, R; Chambers, D; Cole, G; Balogun, O; Spicer, J; Murray, T
Forest Products: Acoustic Humidity Sensor
The new acoustic sensor, designed as a humidity-control system for the paper and textile industries, can both eliminate overdrying and improve product quality by measuring humidity precisely. This new fact sheet explains how the process works.
Poole, L.; Recca, L.
Acoustic Backscatter from Turbulent Microstructure
Acoustic backscatter has produced spectacular images of internal ocean processes for nearly two decades, but interpretation of the images remains ambiguous because several mechanisms can generate measurable backscatter. The authors present what ...
Harvey E. Seim; Michael C. Gregg; R. T. Miyamoto
Doppler Spectra and Estimated Windspeed of a Violent Tornado
Presented in this Paper are Doppler spectra of a very large tornado that occurred on 22 May 1981 near Binger, Oklahoma. Tracking of the tornado was accomplished with the help of a novel "polar spectra display." Bimodal tornado spectral signatures ...
Dusan Zrni?; Donald W. Burgess; Larry Hennington
Estimating Spatial Velocity Statistics with Coherent Doppler Lidar
The spatial statistics of a simulated turbulent velocity field are estimated using radial velocity estimates from simulated coherent Doppler lidar data. The structure functions from the radial velocity estimates are processed to estimate the ...
Rod Frehlich; Larry Cornman
Simulating Range Oversampled Doppler Radar Profiles of Inhomogeneous Targets
A new technique for generating range oversampled profiles of Doppler radar signals that have been backscattered by distributed targets is presented in this paper. The technique was developed for spaceborne cloud radars, but it can just as well be ...
N. A. J. Schutgens
Effects of Wind Turbulence on Coherent Doppler Lidar Performance
The effects of wind turbulence on pulsed coherent Doppler lidar performance are investigated theoretically and with computer simulations. The performance of velocity estimators is determined for the case of a single realization of a wind field ...
Rod Frehlich
Enclosing Shapes for Single-Doppler Radar Features
The primary function of the Terminal Doppler Weather Radar (TDWR) system is to issue microburst alerts when a microburst hazard endangers aircraft. The steps of the algorithm process include 1) determining that a microburst hazard is present, and ...
F. W. Wilson Jr.; R. K. Goodrich; K. Brislawn
Dealiasing of Doppler Radar Velocities Using a Torus Mapping
A novel dealiasing algorithm for Doppler radar velocity data has been developed at the Swedish Meteorological and Hydrological Institute (SMHI). Unlike most other methods, it does not need independent wind information from other instruments (e.g.,...
Günther Haase; Tomas Landelius
Comparison of 2- and 10-µm Coherent Doppler Lidar Performance
The performance of 2- and 10-µm coherent Doppler lidar is presented in terms of the statistical distribution of the maximum-likelihood velocity estimator from simulations for fixed range resolution and fixed velocity search space as a function of ...
Turbulence Kinetic Energy Budget Profiles Derived from Doppler Sodar Measurements
Doppler sodar wind measurements made in light wind conditions in September 1979 near a power plant in Turbigo, Italy, are used to derive terms in the turbulence kinetic energy (TKE) budget. Measurements on five days are grouped into two classes: ...
Gary K. Greenhut; Giangiuseppe Mastrantonio
Objective Tropical Cyclone Center Tracking Using Single-Doppler Radar
This study presents an extension of the ground-based velocity track display (GBVTD)-simplex tropical cyclone (TC) circulation center–finding algorithm to further improve the accuracy and consistency of TC center estimates from single-Doppler radar ...
Michael M. Bell; Wen-Chau Lee
Upscale Evolution of MCSs: Doppler Radar Analysis and Analytical Investigation
The development of two small mesoscale convective systems (MCSs) in northeastern Colorado is investigated via dual-Doppler radar analysis. The first system developed from several initially isolated cumulonimbi, which gradually coalesced into a ...
Ray L. McAnelly; Jason E. Nachamkin; William R. Cotton; Melville E. Nicholls
An electronically steered, wearable transcranial doppler ultrasound system
This thesis details the design of a transcranial Doppler (TCD) ultrasound system to measure cerebral blood flow velocity (CBFV) at the middle cerebral artery (MCA). TCD sonography has been clinically indicated in a variety ...
Pietrangelo, Sabino Joseph
VHF Doppler Radar Observations of Buoyancy Waves Associated with Thunderstorms
The Platteville VHF Doppler radar, located on the Colorado piedmont near Platteville, Colorado, continuously measured the vertical wind velocity during a 12-day period in late July and early August 1981. Measurements were made every 2.5 min on ...
Daren Lu; T. E. VanZandt; W. L. Clark
VHF and UHF Doppler Radars as Tools for Synoptic Research
Applications of VHF and UHF Doppler radars to research in synoptic meteorology are reviewed. We find that these radars show great potential for studies of large scales, but the area of research where the instruments really excel is in studying ...
M. F. Larsen; J. Röttger
Multifrequency Decoding of a Phased Array Doppler Sodar
Doppler sodar is being used for studying the lower part of atmospheric boundary layer (ABL) and wind profiling. To obtain maximum altitude coverage multifrequency transmission has been used along with more transmitted power. In this article, the ...
I. Srinivasa Rao; V. K. Anandan; M. Shravan Kumar
The NIMA Method for Improved Moment Estimation from Doppler Spectra
The NCAR Improved Moments Algorithm (NIMA) for estimating moments from wind measurement devices that measure Doppler spectra as a function of range is described in some detail. Although NIMA's main application has been for real-time processing of ...
Corinne S. Morse; Robert K. Goodrich; Larry B. Cornman
Gust Front Characteristics as Detected by Doppler Radar
Gust fronts produce low altitude wind shear that can be hazardous to aircraft operations, especially during takeoff and landing. Radar meteorologists have long been able to identify gust front signatures in Doppler radar data, but in order to use ...
Diana L. Klingle; David R. Smith; Marilyn M. Wolfson
Asymptotic Properties of an Autocorrelation Coefficient for Coherent Doppler Sonar
A new formula is derived for the asymptotic form of the magnitude of an autocorrelation coefficient for coherent Doppler sonar. The autocorrelation magnitude is shown to be a biased estimator in the limit of infinite ensemble length. Numerical ...
A Statistical Averaging Method for Wind Profiler Doppler Spectra
A new method is presented for Doppler spectral averaging that more reliably identifies the profiler radar return from clear air in the presence of contamination—for example, from migrating bird echoes. These very sensitive radars profile the wind ...
David A. Merritt
On Deriving Vertical Air Motions from Cloud Radar Doppler Spectra
A method for deriving vertical air motions from cloud radar Doppler spectrum measurements is introduced. The method is applicable to cloud volumes containing small particles, in this case liquid droplets, which are assumed to trace vertical air ...
Matthew D. Shupe; Pavlos Kollias; Michael Poellot; Edwin Eloranta
Two Examples of Operational Tornado Warnings Using Doppler Radar Data
The National Weather Service Forecast Office in Denver, Colorado; has access to a variety of new observational datasets via an advanced, interactive workstation. This paper describes the impact of one of these datasets—Doppler radar—on the real-...
Lawrence B. Dunn
Modeling Pulse-to-Pulse Coherent Doppler Sonar
Coherent Doppler sonar provides a powerful tool for probing boundary layer flows under field and laboratory conditions. However, velocity profiling applications of this technique are complicated by characteristic velocity and range ambiguities. ...
L. Zedel
Directional Surface Wave Estimates from Doppler Sonar Data
A quick analysis for deriving directional-frequency spectra from surface grazing Doppler sonar data is presented. Here, "quick" refers to both the short time span of data required and computational ease. The technique employs time and space ...
Jerome A. Smith; Gregory T. Bullard
Radar Wind Profiler Radial Velocity: A Comparison with Doppler Lidar
The accuracy of the radial wind velocity measured with a radar wind profiler will depend on turbulent variability and instrumental noise. Radial velocity estimates of a boundary layer wind profiler are compared with those estimated by a Doppler ...
Stephen A. Cohn; R. Kent Goodrich
Least Squares Reconstruction of Doppler Radar Spectra for Irregular PRT
A least squares method for the reconstruction of Doppler spectra of weather radars with irregular pulse repetition time used to increase the range of unambiguous velocity is presented and evaluated. This method is a robust spectral method that is ...
John Kalogiros
Platform-Motion Correction of Velocity Measured by Doppler Lidar
The NOAA/Earth System Research Laboratory (ESRL) has two coherent Doppler lidar systems that have been deployed on board research vessels to obtain data during several experiments. The instruments measure the wind velocity relative to the motion ...
Reginald J. Hill; W. Alan Brewer; Sara C. Tucker
Airborne Doppler Lidar Observations of Convective Phenomena in Oklahoma
On 30 June 1981, the wind fields around a variety of convective clouds, ranging from large thunderstorm complexes to isolated cumulus congestus, were observed in Oklahoma using an airborne Doppler lidar operated by the National Aeronautics and ...
Eugene W. McCaul Jr.; Howard B. Bluestein; Richard J. Doviak
Using doppler radar images to estimate aircraft navigational heading error
A yaw angle error of a motion measurement system carried on an aircraft for navigation is estimated from Doppler radar images captured using the aircraft. At least two radar pulses aimed at respectively different physical locations in a targeted area are transmitted from a radar antenna carried on the aircraft. At least two Doppler radar images that respectively correspond to the at least two transmitted radar pulses are produced. These images are used to produce an estimate of the yaw angle error.
Doerry, Armin W. (Albuquerque, NM); Jordan, Jay D. (Albuquerque, NM); Kim, Theodore J. (Albuquerque, NM)
The Design of Acoustic Radar Baffles
Compact acoustic antenna arrays, commonly used for profiling urban atmospheres, usually require acoustic baffles to minimize reflections from hard objects and to limit the impact of the 2–6-kHz signals on inhabitants. To facilitate optimum ...
C. J. Werkhoven; S. G. Bradley
Acoustic data transmission through a drill string
Acoustical signals are transmitted through a drill string by canceling upward moving acoustical noise and by preconditioning the data in recognition of the comb filter impedance characteristics of the drill string. 5 figs.
Acoustic and entropy waves in a combustion MHD generator
Simultaneous, sensitive, high frequency measurements of pressure and temperature fluctuations associated with traveling acoustic and entropy pulses were made in a combustion MHD generator under conditions of applied magnetic field (up to 2.2 Tesla) and moderate current density (up to 1.0 amp per square centimeter). The experimental observations and a closed form analytical description of the magneto-acoustic interaction suggest that non-ideal phenomena, including near electrode phenomena, heat transfer, and possible secondary flows can substantially inhibit wave growth or attenuation caused by magneto-acoustic instabilities. Disturbances in the plasma temperature and pressure were created by the rapid discharge of a capacitor into the moving conducting plasma. Inside the generator, transient measurements were taken at three locations using a probe-tube microphone for pressure measurements, a fiber-optic luminosity probe for relative temperature measurements, and transverse mounted voltage pins to measure local voltage profiles. The pressure waves in a laboratory scale generator are not appreciably affected by MHD phenomena, as anticipated from analytical predictions. Temperature waves are affected by the presence of magnetic field and current, showing small attenuation at low currents, greater attenuation at higher currents, and greatest attenuation when either or both magnetic field or currents are absent. These data are explained by a model for secondary flows which affects heat transfer from the plasma. Application of a model for the magneto-acoustic phenomena in large scale MHD generators indicates that property fluctuations may grow appreciably if the electrical resistance in the electrode boundary layers is small with respect to the resistance of the plasma core.
Simons, T.D.
Acoustic Logs | Open Energy Information
Open Energy Info (EERE)
Acoustic Logs Acoustic Logs Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Acoustic Logs Details Activities (7) Areas (6) Regions (0) NEPA(0) Exploration Technique Information Exploration Group: Downhole Techniques Exploration Sub Group: Well Log Techniques Parent Exploration Technique: Well Log Techniques Information Provided by Technique Lithology: determine porosity of layers Stratigraphic/Structural: map discontinuities to determine their orientation. Hydrological: Thermal: Cost Information Low-End Estimate (USD): 1.00100 centUSD 1.0e-3 kUSD 1.0e-6 MUSD 1.0e-9 TUSD / foot Median Estimate (USD): 4.62462 centUSD 0.00462 kUSD 4.62e-6 MUSD 4.62e-9 TUSD / foot High-End Estimate (USD): 16.001,600 centUSD 0.016 kUSD 1.6e-5 MUSD 1.6e-8 TUSD / foot
Measuring the Kuroshio Current with ocean acoustic tomography Naokazu Taniguchia)
of Engineering, Hiroshima University, Hiroshima 739-8527, Japan Chen-Fen Huangb) Institute of Oceanography, National Taiwan University, Taipei 106, Taiwan Arata Kaneko Graduate School of Engineering, Hiroshima University, Hiroshima 739-8527, Japan Cho-Teng Liu Institute of Oceanography, National Taiwan University
Frandsen, Jannette B.
Particle analysis in an acoustic cytometer
The present invention is a method and apparatus for acoustically manipulating one or more particles. Acoustically manipulated particles may be separated by size. The particles may be flowed in a flow stream and acoustic radiation pressure, which may be radial, may be applied to the flow stream. This application of acoustic radiation pressure may separate the particles. In one embodiment, the particles may be separated by size, and as a further example, the larger particles may be transported to a central axis.
Kaduchak, Gregory; Ward, Michael D
Owens Corning Acoustic & Insulation Product Testing ...
... Insulation. [01/T10] ASTM C687 Thermal Resistance of Loose-Fill Building Insulation. Acoustical Testing Services. Accreditation ...
Acoustic Analysis of Adult Speaker Age
Information about the age of the speaker is always present in speech. It is used as perceptual cues to age by human listeners, and can be measured acoustically and used by automatic age estimators. This chapter offers an introduction to the phonetic ... Keywords: Acoustic analysis, Acoustic correlates, Phonetics, Speaker age
Susanne Schötz
Barotropic and Baroclinic Tides in the Central North Pacific Ocean Determined from Long-Range Reciprocal Acoustic Transmissions
Travel times of reciprocal 1000-km range acoustic transmissions, determined from the 1987 Reciprocal Tomography Experiment, are used to study barotropic tidal currents and a large-scale, coherent baroclinic tide in the central North Pacific ...
Brian D. Dushaw; Bruce M. Howe; Bruce D. Cornuelle; Peter F. Worcester; Douglas S. Luther
Acoustic black holes Matt Visser
Acoustic black holes Matt Visser Physics Department Washington University Saint Louis USA Ole Miss you develop a number of use- ful connections between supersonic uid ow and black holes in general is the basis underlying a deep and fruitful analogy between the black holes of Einstein gravity and supersonic
Visser, Matt
Tornado Maintenance Investigated with High-Resolution Dual-Doppler and EnKF Analysis
Dual-Doppler wind synthesis and ensemble Kalman filter analyses produced by assimilating Doppler-on-Wheels velocity data collected in four tornadic supercells are examined in order to further understand the maintenance of tornadoes. Although ...
James Marquis; Yvette Richardson; Paul Markowski; David Dowell; Joshua Wurman
Design and Deployment of a Portable, Pencil-Beam, Pulsed, 3-cm Doppler Radar
A portable, pencil-beam, pulsed, Doppler, 3-cm wavelength radar has been constructed to study a wide variety of meteorological phenomena including tornadoes, severe storms, and boundary layer processes. The new radar, the Doppler on Wheels (DOW), ...
Joshua Wurman; Jerry Straka; Erik Rasmussen; Mitch Randall; Allen Zahrai
Retrieval of Cloud Microphysical Parameters from 94-GHz Radar Doppler Power Spectra
A technique is presented that uses Doppler spectra collected from a vertically pointing 94-GHz radar to reconstruct cloud and precipitation drop size distributions. A conceptual model describing the broadening of Doppler spectra by turbulence was ...
David M. Babb; Johannes Verlinde; Bruce A. Albrecht
High-Resolution Dual-Doppler Analyses of the 29 May 2001 Kress, Texas, Cyclic Supercell
On 29 May 2001, Doppler on Wheels radars collected data on a supercell near Kress, Texas. The supercellular storm, cyclic in nature, produced multiple mesocyclones throughout its lifetime. Dual-Doppler syntheses were conducted using a grid ...
Jeffrey R. Beck; John L. Schroeder; Joshua M. Wurman
Spurious Velocities in Doppler Radar Data Caused by a Moving Antenna Feedhorn
Modern Doppler weather radars use clutter filtering to reduce the strength of ground targets and enhance the detection of meteorological echoes. WSR-88D [NEXRAD (Next Generation Radar) and TDWR (Terminal Doppler Weather Radar)] radars, for ...
Ronald E. Rinehart
Fixed-antenna Pointing-angle Calibration of Airborne Doppler Cloud Radar
Doppler velocity measurements from airborne meteorological Doppler radars require removal of the aircraft motion contribution in order to provide radial velocity of hydrometeor targets. This is a critical step for hydrometeor motion and wind ...
Samuel Haimov; Alfred Rodi
The Pulsed Coherent Doppler Lidar: Observations of Frontal Structure and the Planetary Boundary Layer
The NOAA/WPL pulsed coherent Doppler lidar was used during the Texas Frontal Experiment in 1985 to study mesoscale preconvective atmospheric conditions. On 22 April 1985, the Doppler lidar, in conjunction with serial rawinsonde ascents and ...
Paul J. Neiman; M. A. Shapiro; R. Michael Hardesty; B. Boba Stankov; Rhidian T. Lawrence; Robert J. Zamora; Tamara Hampel
Repeat-Sequence Coding for Improved Precision of Doppler Sonar and Sodar
Repeat-sequence coding is a robust method for improving the precision of velocity estimates from incoherent Doppler sounders. The method involves transmitting a number of repeats of a broadband "subcode." The Doppler shift is estimated from the ...
R. Pinkel; J. A. Smith
Fixed-Antenna Pointing-Angle Calibration of Airborne Doppler Cloud Radar
Simulated Doppler Radar Observations of Inhomogeneous Clouds: Application to the EarthCARE Space Mission
A new simulation technique for spaceborne Doppler radar observations that was developed specifically for inhomogeneous targets is presented. Cloud inhomogeneity affects Doppler observations in two ways. First, line-of-sight velocities within the ...
Doppler Cloud Radar Derived Drop Size Distributions in Liquid Water Stratus Clouds
A cloud particle size retrieval algorithm that uses radar reflectivity factor and Doppler velocity obtained by a 35-GHz Doppler radar and liquid water path estimated from microwave radiometer radiance measurements is developed to infer the size ...
Seiji Kato; Gerald G. Mace; Eugene E. Clothiaux; James C. Liljegren; Richard T. Austin
Effects of Radar Sampling on Single-Doppler Velocity Signatures of Mesocyclones and Tornadoes
Simulated WSR-88D (Weather Surveillance Radar-1988 Doppler) radar data were used to investigate the effects of discrete azimuthal sampling on Doppler velocity signatures of modeled mesocyclones and tornadoes at various ranges from the radar and ...
Vincent T. Wood; Rodger A. Brown
Rainfall Doppler Velocity Measurements from Spaceborne Radar: Overcoming Nonuniform Beam-Filling Effects
For vertical Doppler velocity measurements of a homogeneous rain field, the standard spectral moment estimation techniques commonly used by ground-based and airborne Doppler rain radars can be readily extended for spaceborne application, provided ...
Simone Tanelli; Eastwood Im; Stephen L. Durden; Luca Facheris; Dino Giuli; Eric A. Smith
A Technique for Detecting a Tropical Cyclone Center Using a Doppler Radar
A ground-based Doppler radar technique is developed for detecting a tropical cyclone center position. Accurate determination of the cyclone center position, based on Doppler velocity measurements, will become essential for the issuance of ...
Vincent T. Wood
The Genesis of Three Nonsupercell Tornadoes Observed with Dual-Doppler Radar
Dual-Doppler radar analyses of three tornadoes associated with a multicellular line of storms are presented. The F2–F3 intensity tornadoes occurred on 15 June 1988 near Denver, Colorado, during the Terminal Doppler Weather Radar (TDWR) Project. ...
Rita D. Roberts; James W. Wilson
Climatology of High Cloud Dynamics Using Profiling ARM Doppler Radar Observations
Ice cloud properties are influenced by cloud-scale vertical air motion. Dynamical properties of ice clouds can be determined via Doppler measurements from ground-based, profiling cloud radars. Here, the decomposition of the Doppler velocities into ...
Heike Kalesse; Pavlos Kollias
Retrieval of Microscale Wind and Temperature Fields from Single- and Dual-Doppler Lidar Data
Dual-Doppler lidar observations are used to assess the accuracy of single-Doppler retrievals of microscale wind and temperature fields in a shear-driven convective boundary layer. The retrieval algorithm, which is based on four-dimensional ...
Rob K. Newsom; David Ligon; Ron Calhoun; Rob Heap; Edward Cregan; Marko Princevac
The ELDORA/ASTRAIA Airborne Doppler Weather Radar: High-Resolution Observations from TOGA COARE
The ELDORA/ASTRAIA (Electra Doppler Radar/Analyese Stereoscopic par Impulsions Aeroporte) airborne Doppler weather radar was recently placed in service by the National Center for Atmospheric Research and the Centre d'étude des Environnements ...
Peter H. Hildebrand; Wen-Chau Lee; Craig A. Walther; Charles Frush; Mitchell Randall; Eric Loew; Richard Neitzel; Richard Parsons; Jacques Testud; François Baudin; Alain LeCornec
Observations of a Colorado Tornado. Part II: Combined Photogrammetric and Doppler Radar Analysis
An integrated analysis of photographic and Doppler radar observations of a tornadic storm during the Convection Initiation and Downburst Experiment (CINDE) is presented. High-resolution single-Doppler radar measurements are combined with cloud ...
Roger M. Wakimoto; Brooks E. Martner
Airborne Doppler Lidar Measurements of Valley Flows in Complex Coastal Terrain
Three-dimensional winds obtained with an airborne Doppler lidar are used to investigate the spatial structure of topographically driven flows in complex coastal terrain in Southern California. The airborne Doppler lidar collected four hours of ...
S. F. J. De Wekker; K. S. Godwin; G. D. Emmitt; S. Greco
Florida Current Meanders: A Close Look in June–July 1984
During the Florida Atlantic Coast Transport Study (FACTS), the time and space scales of energetic fluctuations of the Florida Current were observed with current meter moorings and acoustically tracked velocity profilers (PEGASUS). The most ...
R. J. Zantopp; K. D. Leaman; T. N. Lee
Structure and Variability of the Florida Current at 27°N: April 1982–July 1984
Results of a two-year field experiment as part of the SubTropical Atlantic Climate Studies (STACS) program in the Straits of Florida are presented. Temperature and absolute ocean current observations were obtained by PEGASUS acoustic current ...
Kevin D. Leaman; Robert L. Molinari; Peter S. Vertes
A Real-Time Four-Dimensional Doppler Dealiasing Scheme
A new dealiasing scheme uses the full four-dimensionality available in an operational Doppler radar data stream. It examines one tilt angle at a time, beginning at the highest elevation where clutter is minimal and gate-to-gate shear is typically ...
Curtis N. James; Robert A. Houze Jr.
Details of Colliding Thunderstorm Outflows as Observed by Doppler Lidar
Three cases of colliding outflow boundaries are examined using data collected from the NOAA Doppler lidar and a meteorological tower during the summer of 1986 near Boulder, Colorado. The data are unique because the lidar and the 300 m tower were ...
J. M. Intrieri; A. J. Bedard Jr.; R. M. Hardesty
Comparison of a Doppler Sodar with Bivanes and Cup Anemometers
A commercial Doppler sodar was operated near a 300-m tower instrumented with bivanes and cup anemometers. Sodar measurements of wind speed and direction and a turbulence variable (?w) were compared with tower measurements at 90, 180, and 300 m. A ...
Robert J. Kurzeja
A 35-GHz Scanning Doppler Radar for Fog Observations
To observe fog, a 35-GHz scanning Doppler radar was designed, assembled, and tested. The radar, mounted on a flatbed vehicle for portability, transmits peak powers of 100 kW in a pulse of 0.5-µs width and a beamwidth of 0.3°. Thus, a reflectivity ...
Kyosuke Hamazu; Hiroyuki Hashiguchi; Toshio Wakayama; Tomoya Matsuda; Richard J. Doviak; Shoichiro Fukao
The Use of Phased-Array Doppler Sonars near Shore
Phased-array Doppler sonars (PADS) have been used to probe an area several hundred meters on a side with 8-m spatial resolution, sampling every second or less with under 2 cm s?1 rms velocity error per sample. Estimates from two systems were ...
Coplanar Doppler Lidar Retrieval of Rotors from T-REX
Dual-Doppler analysis of data from two coherent lidars during the Terrain-Induced Rotor Experiment (T-REX) allows the retrieval of flow structures, such as vortices, during mountain-wave events. The spatial and temporal resolution of this ...
Michael Hill; Ron Calhoun; H. J. S. Fernando; Andreas Wieser; Andreas Dörnbrack; Martin Weissmann; Georg Mayr; Robert Newsom
Doppler Radar Observations of Dust Devils in Texas
Analyses of a dust-devil dataset collected in northwest Texas are presented. The data were collected just above the ground at close range with a mobile, W-band (3-mm wavelength) Doppler radar having an azimuthal (radial) resolution of 3–5 m (30 m)...
Howard B. Bluestein; Christopher C. Weiss; Andrew L. Pazmany
Acoustic horizons in nuclear fluids
We consider a hydrodynamic description of the spherically symmetric outward flow of nuclear matter, accommodating dispersion in it as a very weak effect. About the resulting stationary conditions in the flow, we apply an Eulerian scheme to derive a fully nonlinear equation of a time-dependent radial perturbation. In its linearized limit, with no dispersion, this equation implies the static acoustic horizon of an analogue gravity model. We, however, show that time-dependent nonlinear effects destabilize the static horizon. We also model the perturbation as a high-frequency travelling wave, and perform a {\\it WKB} analysis, in which the effect of weak dispersion is studied iteratively. We show that even arbitrarily small values of dispersion make the horizon fully opaque to any acoustic disturbance propagating against the bulk flow, with the amplitude and the energy flux of the radial perturbation undergoing a discontinuity at the horizon, and decaying exponentially just outside it.
Niladri Sarkar; Abhik Basu; Jayanta K. Bhattacharjee; Arnab K. Ray
Cylindrical acoustic levitator/concentrator
A low-power, inexpensive acoustic apparatus for levitation and/or concentration of aerosols and small liquid/solid samples having particulates up to several millimeters in diameter in air or other fluids is described. It is constructed from a commercially available, hollow cylindrical piezoelectric crystal which has been modified to tune the resonance frequency of the breathing mode resonance of the crystal to that of the interior cavity of the cylinder. When the resonance frequency of the interior cylindrical cavity is matched to the breathing mode resonance of the cylindrical piezoelectric transducer, the acoustic efficiency for establishing a standing wave pattern in the cavity is high. The cylinder does not require accurate alignment of a resonant cavity. Water droplets having diameters greater than 1 mm have been levitated against the force of gravity using; less than 1 W of input electrical power. Concentration of aerosol particles in air is also demonstrated.
Kaduchak, Gregory (Los Alamos, NM); Sinha, Dipen N. (Los Alamos, NM)
Acoustic plane wave preferential orientation of metal oxide superconducting materials
A polycrystalline metal oxide such as YBa.sub.2 Cu.sub.3 O.sub.7-X (where 0current densities. By aligning the two-dimensional Cu-O layers which carry the current in the superconducting state in the a- and b-directions, i.e., within the basal plane, a high degree of crystalline axes alignment is provided between adjacent grains permitting the conduction of high current densities. With the superconducting metal oxide in the form of a ceramic slip which has not yet set, orientation of the crystal basal planes parallel with the direction of desired current flow is accomplished by an applied acoustic plane wave in the acoustic or ultrasonic frequency range (either progressive or standing) in applying a torque to each crystal particle. The ceramic slip is then set and fired by conventional methods to produce a conductor with preferentially oriented grains and substantially enhanced current carrying capacity.
Tolt, Thomas L. (North Olmsted, OH); Poeppel, Roger B. (Glen Ellyn, IL)
Wind Turbine Acoustic Noise A white paper
Wind Turbine Acoustic Noise A white paper Prepared by the Renewable Energy Research Laboratory...................................................................... 8 Sound from Wind Turbines .............................................................................................. 10 Sources of Wind Turbine Sound
Massachusetts at Amherst, University of
Ricoh Company LTD. Acoustical Testing Laboratory
Acoustical Testing Laboratory. ... 143-8555 JAPAN Contact: Mr. Seiji Nakamura Phone: 81-046-292-3871 Fax: E-Mail: email@example.com ...
Acoustic concentration of particles in fluid flow
An apparatus for acoustic concentration of particles in a fluid flow includes a substantially acoustically transparent membrane and a vibration generator that define a fluid flow path therebetween. The fluid flow path is in fluid communication with a fluid source and a fluid outlet and the vibration generator is disposed adjacent the fluid flow path and is capable of producing an acoustic field in the fluid flow path. The acoustic field produces at least one pressure minima in the fluid flow path at a predetermined location within the fluid flow path and forces predetermined particles in the fluid flow path to the at least one pressure minima.
Ward, Michael D. (Los Alamos, NM); Kaduchak, Gregory (Los Alamos, NM)
... that at full load in liquid injection systems, extra energy or perturbation is ... The acoustic modulation is generated by a piezoelectric crystal driven by a ...
Time synchronization for underwater acoustic sensor networks.
??The unique properties of underwater acoustic communications, such as large and time-varying propagation, low and range dependent bandwidth, and adverse operating environment make the synchronization… (more)
Khandoker, Tarik-Ul Islam
... are developing a long-wavelength acoustic flowmeter (LWAF) for accurate, economical measurements of exhaust flows from coal-burning power ...
Alion Science and Technology / Riverbank Acoustical ...
... E2179 Laboratory Measurement of the Effectiveness of Floor Coverings in Reducing ... 08/P61] AAMA 1801 Acoustical Rating of Windows, Doors and ...
Prospects for Doppler cooling of three-electronic-level molecules
Analogous to the extension of laser cooling techniques from two-level to three-level atoms, Doppler cooling of molecules with an intermediate electronic state is considered. In particular, we use a rate-equation approach to simulate cooling of SiO{sup +}, in which population buildup in the intermediate state is prevented by its short lifetime. We determine that Doppler cooling of SiO{sup +} can be accomplished without optically repumping from the intermediate state, at the cost of causing undesirable parity flips and rotational diffusion. Since the necessary repumping would require a large number of continuous-wave lasers, optical pulse shaping of a femtosecond laser is proposed as an attractive alternative. Other candidate three-electron-level molecules are also discussed.
Nguyen, J. H. V.; Odom, B. [Department of Physics and Astronomy, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208 (United States)
A Fisheye Lens as a Photonic Doppler Velocimetry Probe
These presentation visuals report an instrument that, by use of a fish-eye lens, generates a beat signal using fiber mixing of unshifted light with Doppler-shifted light and measures the beat frequency. Ray trace diagrams are shown to illustrate advantages and disadvantages. The authors find their instrument has a long tracking distance, and large angle coverage. Index matching eases assembly, reduces return loss and flattens the field.
Frogget, B. C.
Neutrino Detection, Position Calibration and Marine Science with Acoustic Arrays in the Deep Sea
Arrays of acoustic receivers are an integral part of present and potential future Cherenkov neutrino telescopes in the deep sea. They measure the positions of individual detector elements which vary with time as an effect of undersea currents. At the same time, the acoustic receivers can be employed for marine science purposes, in particular for monitoring the ambient noise environment and the signals emitted by the fauna of the sea. And last but not least, they can be used for studies towards acoustic detection of ultra-high-energy neutrinos. Measuring acoustic pressure pulses in huge underwater acoustic arrays with an instrumented volume of the order of 100 km^3 is a promising approach for the detection of cosmic neutrinos with energies exceeding 1 EeV. Pressure signals are produced by the particle cascades that evolve when neutrinos interact with nuclei in water, and can be detected over large distances in the kilometre range. In this article, the status of acoustic detection will be reviewed and plans for...
Lahmann, Robert
Optimal adaptive sampling for continental shelf acoustic forecasting.
Shallow water acoustic propagation variability is driven by bathymetry and geo?acoustic and oceanographic variabilities. At the shelf?break
Kevin D. Heaney
Reliable Data Communication and Storage in Underwater Acoustic Networks.
??Underwater acoustic communications (UAC) and networking (UAN) are promising paradigms for various oceanic applications. However, acoustic signal transmissions are characterized by long propagation delay, frequency-dependent… (more)
Cao, Rui
Acoustically enhanced heat exchange and drying apparatus
A heat transfer drying apparatus includes an acoustically augmented heat transfer chamber for receiving material to be dried. The chamber includes a first heat transfer gas inlet, a second heat transfer gas inlet, a material inlet, and a gas outlet which also serves as a dried material and gas outlet. A non-pulsing first heat transfer gas source provides a first drying gas to the acoustically augmented heat transfer chamber through the first heat transfer gas inlet. A valveless, continuous second heat transfer gas source provides a second drying gas to the acoustically augmented heat transfer chamber through the second heat transfer gas inlet. The second drying gas also generates acoustic waves which bring about acoustical coupling with the gases in the acoustically augmented heat transfer chamber. The second drying gas itself oscillates at an acoustic frequency of approximately 180 Hz due to fluid mechanical motion in the gas. The oscillations of the second heat transfer gas coupled to the first heat transfer gas in the acoustically augmented heat transfer chamber enhance heat and mass transfer by convection within the chamber. 3 figs.
Bramlette, T.T.; Keller, J.O.
Acoustic impedance inversion of the Lower Permian carbonate buildups in the Permian Basin, Texas
Carbonate reservoirs are usually diffcult to map and identify in seismic sections due to their complex structure, lithology and diagenetic frabrics. The Midland Basin, located in the Permian Basin of West Texas, is an excellent example of these complex carbonate structures. In order to obtain a better characterization and imaging of the carbonate buildups, an acoustic impedance inversion is proposed here. The resolution of the acoustic impedance is the same as the input seismic data, which is greatly improved with the addition of the low frequency content extracted from well data. From the broadband volume, high resolution maps of acoustic impedance distributions were obtained, and therefore the locations of carbonate buildups were easily determined. A correlation between acoustic impedance and porosity extracted from well data shows that areas with high acoustic impedance were correlated with low porosity values, whereas high porosities were located in areas of low acoustic impedance. Theoretical analyses were performed using the time-average equation and the Gassmann equation. These theoretical models helped to understand how porosity distributions affect acoustic impedance. Both equations predicted a decrease in acoustic impedance as porosity increases. Inversion results showed that average porosity values are 5% [plus or minus] 5%, typical for densely cemented rocks. Previous studies done in the study area indicate that grains are moderately to well-sorted. This suggests that time-average approximation will overestimate porosity values and the Gassmann approach better predicts the measured data. A comparison between measured data and the Gassmann equation suggests that rocks with low porosities (less than 5%) tend to have high acoustic impedance values. On the other hand, rocks with higher porosities (5% to 10%) have lower acoustic impedance values. The inversion performed on well data also shows that the ?uid bulk modulus for currently producing wells is lower than in non-productive wells, (wells with low production rates for brine and hydrocarbons), which is consistent with pore ?uids containing a larger concentration of oil. The acoustic impedance inversion was demonstrated to be a robust technique for mapping complex structures and estimating porosities as well. However, it is not capable of differentiating different types of carbonate buildups and their origin.
Pablo, Buenafama Aleman
Three-Dimensional Nonlinear Acoustical Holography
Nearfield Acoustical Holography (NAH) is an acoustic field visualization technique that can be used to reconstruct three-dimensional (3-D) acoustic fields by projecting two-dimensional (2-D) data measured on a hologram surface. However, linear NAH algorithms developed and improved by many researchers can result in significant reconstruction errors when they are applied to reconstruct 3-D acoustic fields that are radiated from a high-level noise source and include significant nonlinear components. Here, planar, nonlinear acoustical holography procedures are developed that can be used to reconstruct 3-D, nonlinear acoustic fields radiated from a high-level noise source based on 2-D acoustic pressure data measured on a hologram surface. The first nonlinear acoustic holography procedure is derived for reconstructing steady-state acoustic pressure fields by applying perturbation and renormalization methods to nonlinear, dissipative, pressure-based Westervelt Wave Equation (WWE). The nonlinear acoustic pressure fields radiated from a high-level pulsating sphere and an infinite-size, vibrating panel are used to validate this procedure. Although the WWE-based algorithm is successfully validated by those two numerical simulations, it still has several limitations: (1) Only the fundamental frequency and its second harmonic nonlinear components can be reconstructed; (2) the application of this algorithm is limited to mono-frequency source cases; (3) the effects of bent wave rays caused by transverse particle velocities are not included; (4) only acoustic pressure fields can be reconstructed. In order to address the limitations of the steady-state, WWE-based procedure, a transient, planar, nonlinear acoustic holography algorithm is developed that can be used to reconstruct 3-D nonlinear acoustic pressure and particle velocity fields. This procedure is based on Kuznetsov Wave Equation (KWE) that is directly solved by using temporal and spatial Fourier Transforms. When compared to the WWE-based procedure, the KWE-based procedure can be applied to multi-frequency source cases where each frequency component can contain both linear and nonlinear components. The effects of nonlinear bent wave rays can be also considered by using this algorithm. The KWE-based procedure is validated by conducting an experiment with a compression driver and four numerical simulations. The numerical and experimental results show that holographically-projected acoustic fields match well with directly-calculated and directly-measured fields.
Niu, Yaying
Comparative Performance of Acoustic-tagged and PIT-tagged Juvenile Salmonids
Numerous research tools and technologies are currently being used to evaluate fish passage and survival to determine the impacts of the Federal Columbia River Power System (FCRPS) on endangered and threatened juvenile salmonids, including PIT tags, balloon tags, hydroacoustic evaluations, radio telemetry, and acoustic telemetry. Each has advantages and disadvantages, but options are restricted in some situations because of limited capabilities of a specific technology, lack of detection capability downstream, or availability of adequate numbers of fish. However, there remains concern about the comparative effects of the tag or the tagging procedure on fish performance. The recently developed Juvenile Salmonid Acoustic Telemetry System (JSATS) acoustic transmitter is the smallest active acoustic tag currently available. The goal of this study was to determine whether fish tagged with the JSATS acoustic-telemetry tag can provide unbiased estimates of passage behavior and survival within the performance life of the tag. We conducted both field and laboratory studies to assess tag effects. For the field evaluation we released a total of 996 acoustic-tagged fish in conjunction with 21,026 PIT-tagged fish into the tailrace of Lower Granite Dam on 6 and 13 May. Travel times between release and downstream dams were not significantly different for the majority of the reaches between acoustic-tagged and PIT-tagged fish. In addition to the field evaluation, a series of laboratory experiments were conducted to determine if growth and survival of juvenile Chinook salmon surgically implanted with acoustic transmitters is different than untagged or PIT tagged juvenile Chinook salmon. Only yearling fish with integrated and non-integrated transmitters experienced mortalities, and these were low (tag treatments ranged up to 7.7% while integrated and non-integrated treatments had slightly higher rates (up to 8.3% and 7.9% respectively). No acoustic transmitters were shed by yearling fish during the course of the 90 day study. Up to 7.8% of subyearling fish expelled transmitters. Tags were expelled from 5 to 63 days post-surgery. The average time to expulsion was 27 days; few fish expelled transmitters within 14 days of implantation or less. Histological results suggest that inflammation associated with implantation of an acoustic transmitter can produce fibrous tissue which can invade and possibly damage internal organs soon after implantation. Reactions severe enough to damage organs however, were limited to only ~20% of subyearling Chinook salmon, all of which were under 101mm and 12g at tagging. The infiltration of the fibrous tissue into organs was observed most often in fish held for 21 days and appeared to decrease in subsequent holding times.
Hockersmith, Eric E.; Brown, Richard S.; Liedtke, Theresa L.
Numerous research tools and technologies are currently being used to evaluate fish passage and survival to determine the impacts of the Federal Columbia River Power System (FCRPS) on endangered and threatened juvenile salmonids, including PIT tags, balloon tags, hydroacoustic evaluations, radio telemetry, and acoustic telemetry. Each has advantages and disadvantages, but options are restricted in some situations because of limited capabilities of a specific technology, lack of detection capability downstream, or availability of adequate numbers of fish. However, there remains concern about the comparative effects of the tag or the tagging procedure on fish performance. The recently developed Juvenile Salmonid Acoustic Telemetry System (JSATS) acoustic transmitter is the smallest active acoustic tag currently available. The goal of this study was to determine whether fish tagged with the JSATS acoustic-telemetry tag can provide unbiased estimates of passage behavior and survival within the performance life of the tag. We conducted both field and laboratory studies to assess tag effects. For the field evaluation we released a total of 996 acoustic-tagged fish in conjunction with 21,026 PIT-tagged fish into the tailrace of Lower Granite Dam on 6 and 13 May. Travel times between release and downstream dams were not significantly different for the majority of the reaches between acoustic-tagged and PIT-tagged fish. In addition to the field evaluation, a series of laboratory experiments were conducted to determine if growth and survival of juvenile Chinook salmon surgically implanted with acoustic transmitters is different than untagged or PIT tagged juvenile Chinook salmon. Only yearling fish with integrated and non-integrated transmitters experienced mortalities, and these were low (<4.5%). Mortality among sub-yearling control and PIT-tag treatments ranged up to 7.7% while integrated and non-integrated treatments had slightly higher rates (up to 8.3% and 7.9% respectively). No acoustic transmitters were shed by yearling fish during the course of the 90 day study. Up to 7.8% of subyearling fish expelled transmitters. Tags were expelled from 5 to 63 days post-surgery. The average time to expulsion was 27 days; few fish expelled transmitters within 14 days of implantation or less. Histological results suggest that inflammation associated with implantation of an acoustic transmitter can produce fibrous tissue which can invade and possibly damage internal organs soon after implantation. Reactions severe enough to damage organs however, were limited to only ~20% of subyearling Chinook salmon, all of which were under 101mm and 12g at tagging. The infiltration of the fibrous tissue into organs was observed most often in fish held for 21 days and appeared to decrease in subsequent holding times.
Piezoelectric materials used in underwater acoustic transducers
Piezoelectric materials have been used in underwater acoustic transducers for nearly a century. In this paper, we reviewed four different types of piezoelectric materials: piezoelectric ceramics, single crystals, composites, and polymers, which are widely used in underwater acoustic transducers nowadays. Piezoelectric ceramics are the most dominant material type and are used as a single-phase material or one of the end members in composites. Piezoelectric single crystals offer outstanding electromechanical response but are limited by their manufacturing cost. Piezoelectric polymers provide excellent acoustic impedance matching and transducer fabrication flexibility although their piezoelectric properties are not as good as ceramics and single crystals. Composites combined the merits of ceramics and polymers and are receiving increased attention. The typical structure and electromechanical properties of each type of materials are introduced and discussed with respect to underwater acoustic transducer applications. Their advantages and disadvantages are summarized. Some of the critical design considerations when developing underwater acoustic transducers with these materials are also touched upon.
Li, Huidong; Deng, Zhiqun; Carlson, Thomas J.
Sparse Multichannel Estimation Algorithm for Cooperative Underwater Acoustic Communication Networks
Introduction: Cooperative Underwater Acoustic Communicationsgain for wireless and underwater network in interference-
Richard, Nick; Mitra, Urbasi
Effect of window reflections on photonic Doppler velocimetry measurements
Photonic Doppler velocimetry (PDV) has rapidly become a standard diagnostic for measuring velocities in dynamic compression research. While free surface velocity measurements are fairly straightforward, complications occur when PDV is used to measure a dynamically loaded sample through a window. Fresnel reflections can severely affect the velocity and time resolution of PDV measurements, especially for low-velocity transients. Shock experiments of quartz compressed between two sapphire plates demonstrate how optical window reflections cause ringing in the extracted PDV velocity profile. Velocity ringing is significantly reduced by using either a wedge window or an antireflective coating.
Ao, T.; Dolan, D. H. [Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)
Doppler lidar observations of Russian forest fire plumes over Helsinki
Russia led to elevated concentrations of fine particles reducing air quality in southern Finland over a number of weeks. Predominately easterly and south-easterly winds resulted in smoke plumes extending over the Gulf of Finland and affecting eastern and southern Finland during 7–14 August 2006 and 21–23 August 2006. This article describes observations using Doppler lidar of two episodes where smoke plumes from the Russian forest fires were evident over the Helsinki area on 7 and 9 August 2006. The observations were made during a convective field campaign, part of the Helsinki Testbed, an international mesoscale meteorology research project running from
K E Bozier; G N Pearson; C G Collier; Halo Photonics
Speaker verification system using acoustic data and non-acoustic data
A method and system for speech characterization. One embodiment includes a method for speaker verification which includes collecting data from a speaker, wherein the data comprises acoustic data and non-acoustic data. The data is used to generate a template that includes a first set of "template" parameters. The method further includes receiving a real-time identity claim from a claimant, and using acoustic data and non-acoustic data from the identity claim to generate a second set of parameters. The method further includes comparing the first set of parameters to the set of parameters to determine whether the claimant is the speaker. The first set of parameters and the second set of parameters include at least one purely non-acoustic parameter, including a non-acoustic glottal shape parameter derived from averaging multiple glottal cycle waveforms.
Gable, Todd J. (Walnut Creek, CA); Ng, Lawrence C. (Danville, CA); Holzrichter, John F. (Berkeley, CA); Burnett, Greg C. (Livermore, CA)
Sub-pilot testing of an acoustically enhanced cyclone for PFBC
The overall program objective is to demonstrate, on the subpilot-scale, the effectiveness of an acoustically enhanced cyclone collector under high temperature, high pressure conditions found in coal-fired pressurized fluidized bed combustion (PFBC) combined cycle power generating systems. The data obtained will be used to design an acoustically enhanced cyclone gas cleanup system which can meet the New Source Performance Standards (NSPS) particulate control level with capital and operating costs significantly lower than currently available with conventional cyclones and post turbine particulate control.
Galica, M.A.; Rawlins, D.C.
Copper vapor laser acoustic thermometry system
A copper vapor laser (CVL) acoustic thermometry system is disclosed. The invention couples an acoustic pulse a predetermined distance into a laser tube by means of a transducer and an alumina rod such that an echo pulse is returned along the alumina rod to the point of entry. The time differential between the point of entry of the acoustic pulse into the laser tube and the exit of the echo pulse is related to the temperature at the predetermined distance within the laser tube. This information is processed and can provide an accurate indication of the average temperature within the laser tube.
Galkowski, J.J.
A heat transfer apparatus includes a first chamber having a first heat transfer gas inlet, a second heat transfer gas inlet, and an outlet. A first heat transfer gas source provides a first gas flow to the first chamber through the first heat transfer gas inlet. A second gas flow through a second chamber connected to the side of the first chamber, generates acoustic waves which bring about acoustical coupling of the first and second gases in the acoustically augmented first chamber. The first chamber may also include a material inlet for receiving material to be dried, in which case the gas outlet serves as a dried material and gas outlet.
Bramlette, T. Tazwell (Livermore, CA); Keller, Jay O. (Oakland, CA)
Particle collection enhancement by acoustics
The overall objective of this project is to demonstrate pulse combustion induced acoustic enhancement of coal ash agglomeration and sulfur capture efficiency at conditions typical of proposed direct coal-fired turbines. The MTCI proprietary approach results in agglomerates that allow the use of conventional cyclones to achieve very high particulate collection efficiency and eliminates the need for barrier filters which pose concerns regarding durability and economics. The goal of the program is to support the mission of the Department of Energy (DOE) for developing coal-fired combustion gas turbines. The MTCI concept can be packaged either as a hot flue gas clean-up subsystem for the existing combustor island configurations or as an alterative primary pulse combustor island with integrated sulfur capture, particulate agglomeration and capture, alkali gettering and NO{sub x} emissions control.
Mansour, M.N.; Chandran, R.R.; Duqum, J.N. [Manufacturing and Technology Conversion International, Inc., Columbia, MD (United States); Scaroni, A.W.; Koopman, G.H. [Pennsylvania State Univ., University Park, PA (United States); Loth, J.L. [West Virginia Univ., Morgantown, WV (United States)
Acoustic emission non-destructive testing of structures using source location techniques.
The technology of acoustic emission (AE) testing has been advanced and used at Sandia for the past 40 years. AE has been used on structures including pressure vessels, fire bottles, wind turbines, gas wells, nuclear weapons, and solar collectors. This monograph begins with background topics in acoustics and instrumentation and then focuses on current acoustic emission technology. It covers the overall design and system setups for a test, with a wind turbine blade as the object. Test analysis is discussed with an emphasis on source location. Three test examples are presented, two on experimental wind turbine blades and one on aircraft fire extinguisher bottles. Finally, the code for a FORTRAN source location program is given as an example of a working analysis program. Throughout the document, the stress is on actual testing of real structures, not on laboratory experiments.
Beattie, Alan G.
Simulation and Analysis Chain for Acoustic Ultra-high Energy Neutrino Detectors in Water
Acousticneutrinodetectionisapromisingapproachforlarge-scaleultra-highenergyneutrinodetectorsinwater.In this article, a Monte Carlo simulation chain for acoustic neutrino detection devices in water will be presented. The simulation chain covers the generation of the acoustic pulse produced by a neutrino interaction and its propagation to the sensors within the detector. Currently, ambient and transient noise models for the Mediterranean Sea and simulations of the data acquisition hardware, equivalent to the one used in ANTARES/AMADEUS, are implemented. A pre-selection scheme for neutrino-like signals based on matched filtering is employed, as it is used for on-line filtering. To simulate the whole processing chain for experimental data, signal classification and acoustic source reconstruction algorithms are integrated in an analysis chain. An overview of design and capabilities of the simulation and analysis chain will be presented and preliminary studies will be discussed.
Neff, M; Enzenhöfer, A; Graf, K; Hößl, J; Katz, U; Lahmann, R; Sieger, C
A new fisheye lens design is used as a miniature probe to measure the velocity distribution of an imploding surface along many lines of sight. Laser light, directed and scattered back along each beam on the surface, is Doppler shifted by the moving surface and collected into the launching fiber. The received light is mixed with reference laser light in each optical fiber in a technique called photonic Doppler velocimetry, providing a continuous time record. An array of single-mode optical fibers sends laser light through the fisheye lens. The lens consists of an index-matching positive element, two positive doublet groups, and two negative singlet elements. The optical design minimizes beam diameters, physical size, and back reflections for excellent signal collection. The fiber array projected through the fisheye lens provides many measurement points of surface coverage over a hemisphere with very little crosstalk. The probe measures surface movement with only a small encroachment into the center of the cavity. The fiber array is coupled to the index-matching element using index-matching gel. The array is bonded and sealed into a blast tube for ease of assembly and focusing. This configuration also allows the fiber array to be flat polished at a common object plane. In areas where increased measurement point density is desired, the fibers can be close packed. To further increase surface density coverage, smaller-diameter cladding optical fibers may be used.
Frogget, B C; Cox, B C; DeVore, D O; Esquibel, D L; Frayer, D K; Furlanetto, M R; Holtkamp, D B; Kaufman, M I; Malone, R M
Acoustics Program Acoustics Program Developed to help designers accurately model the sound level reaching building tenant's ears, the Trane Acoustics Program (TAP) "projects" equipment sound power data through the surroundings (e.g., floors, ductwork, walls), to estimate the sound level that will be heard. Industry-standard calculations published by ASHRAE's 1991 Algorithms for HVAC Acoustics handbook are the basis for this estimate. In TAP, you can model the conditions of an HVAC system by choosing specific equipment and building component criteria. TAP will analyze the sound path and calculate the total effect for the enclosed space. You can continuously adjust the data and system design criteria to compare the results effortlessly. TAP will even plot presentation quality graphs of
Global Ocean Warming: An Acoustic Measure?
Explosions of 300 lbs of TNT at 1 km depth off Perth, Australia were recorded on Bermuda hydrophones, demonstrating 30 years age the feasibility of global acoustic transmissions. Climate-induced changes in ocean temperature (and hence in sound ...
W. H. Munk; A. M. G. Forbes
Underwater acoustic MIMO OFDM: an experimental analysis
Performance of multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) is analyzed on an experimental shallow water acoustic channel. Different modulation levels, numbers of subcarriers and ...
Palou Visa, Guillem
Audioptimization : global-based acoustic design
Acoustic design is a difficult problem, because the human perception of sound depends on such things as decibel level, direction of propagation, and attenuation over time, none of which are tangible or visible. The advent ...
Monks, Michael Christopher, 1958-
Scattering of ion-acoustic solitons
A series of experiments is described that is designed to ascertain the properties of the scattering of planar ion-acoustic solitons from objects of various shapes. The scattered solitons are compared with those radiated from the same objects.
Raychaudhuri, S.; Chang, H.; Tsikis, E.K.; Lonngren, K.E.
Weather Classification Using Passive Acoustic Drifters
Weather observations are needed in remote oceanic regions to support numerical weather forecast models, to provide surface truth for satellite sensors, and to help understand global weather patterns. An acoustic mini-drifting buoy using no moving ...
Jeffrey A. Nystuen; Harry D. Selsor
Errors in Radio Acoustic Sounding of Temperature
With the use of simultaneous correction for radial wind, the accuracy of radio acoustic sounding systems for the measurement of temperature has been substantially improved. The temperature accuracy can now be affected by a number of factors that ...
Wayne M. Angevine; W. L. Ecklund
Acoustic Energy Storage in Single Bubble Sonoluminescence
Single bubble sonoluminescence is understood in terms of a shock focusing towards the bubble center. We present a mechanism for significantly enhancing the effect of shock focusing, arising from the storage of energy in the acoustic modes of the gas. The modes with strongest coupling are not spherically symmetric. The storage of acoustic energy gives a framework for understanding how light intensities depend so strongly on ambient gases and liquids and suggests that the light intensities of successive flashes are highly correlated.
Michael P. Brenner; Sascha Hilgenfeldt; Detlef Lohse; Rodolfo R. Rosales
Brain activity and presence: a preliminary study in different immersive conditions using transcranial Doppler monitoring
Transcranial Doppler (TCD) sonography is a brain activity measurement technique that monitors the hemodynamic characteristics of the major cerebral arteries in normal and pathological conditions. As it is not invasive, it can be easily used in combination ... Keywords: Brain activity, Immersion, Navigation, Transcranial Doppler, Virtual reality
Beatriz Rey; Mariano Alcańiz; José Tembl; Vera Parkhutik
Sea Ice Identification and Derivation of Its Velocity Field by X-Band Doppler Radar
In this study a 3D scanning X-band Doppler radar (XDR) was deployed near the coast of the Sea of Okhotsk, Hokkaido, Japan, in November 2005 to simultaneously observe sea ice and snow clouds. Doppler radars are commonly used to detect wind fields ...
Yasushi Fujiyoshi; Koji Osumi; Masayuki Ohi; Yoshinori Yamada
Performance of Maximum Likelihood Estimators of Mean Power and Doppler Velocity with A Priori Knowledge of Spectral Width
The performance of the maximum likelihood (ML) estimates of mean velocity and signal power for Doppler radar and Doppler lidar, assuming known signal spectral width, is presented. The results are compared with the theoretical limit of the Cramer–...
A Dual-Pulse Repetition Frequency Scheme for Mitigating Velocity Ambiguities of the NOAA P-3 Airborne Doppler Radar
To mitigate some of the deleterious effects of the relatively small unambiguous Doppler velocity range (Nyquist interval) of airborne X-band Doppler radars, a technique has been developed to extend this interval. This technique, termed the batch-...
David P. Jorgensen; Tom R. Shepherd; Alan S. Goldstein
Assimilating Coherent Doppler Lidar Measurements into a Model of the Atmospheric Boundary Layer. Part II: Sensitivity Analyses
A series of trials are performed to evaluate the sensitivity of a 4DVAR algorithm for retrieval of microscale wind and temperature fields from single-Doppler lidar data. These trials use actual Doppler lidar measurements to examine the ...
Rob K. Newsom; Robert M. Banta
Initialization of a Cloud-Resolving Model with Airborne Doppler Radar Observations of an Oceanic Tropical Convective System
Doppler radar–derived fields of wind and reflectivity, retrieved temperature perturbations, estimated water vapor, and cloud water contents are used to initialize a nonhydrostatic cloud-resolving model. Airborne Doppler data collected in a ...
Soline Bielli; Frank Roux
In Situ, Doppler Radar, and Video Observations of the Interior Structure of a Tornado and the Wind–Damage Relationship
Direct observations of the winds inside a tornado were obtained with an instrumented armored vehicle, the Tornado Intercept Vehicle (TIV), and integrated with finescale mobile Doppler radar (Doppler on Wheels) data revealing, for the first time, the ...
Joshua Wurman; Karen Kosiba; Paul Robinson
Tunable damper for an acoustic wave guide
A damper for tunably damping acoustic waves in an ultrasonic waveguide is provided which may be used in a hostile environment such as a nuclear reactor. The area of the waveguide, which may be a selected size metal rod in which acoustic waves are to be damped, is wrapped, or surrounded, by a mass of stainless steel wool. The wool wrapped portion is then sandwiched between tuning plates, which may also be stainless steel, by means of clamping screws which may be adjusted to change the clamping force of the sandwiched assembly along the waveguide section. The plates are preformed along their length in a sinusoidally bent pattern with a period approximately equal to the acoustic wavelength which is to be damped. The bent pattern of the opposing plates are in phase along their length relative to their sinusoidal patterns so that as the clamping screws are tightened a bending stress is applied to the waveguide at 180/sup 0/ intervals along the damping section to oppose the acoustic wave motions in the waveguide and provide good coupling of the wool to the guide. The damper is tuned by selectively tightening the clamping screws while monitoring the amplitude of the acoustic waves launched in the waveguide. It may be selectively tuned to damp particular acoustic wave modes (torsional or extensional, for example) and/or frequencies while allowing others to pass unattenuated.
Rogers, S.C.
A damper for tunably damping acoustic waves in an ultrasonic waveguide is provided which may be used in a hostile environment such as a nuclear reactor. The area of the waveguide, which may be a selected size metal rod in which acoustic waves are to be damped, is wrapped, or surrounded, by a mass of stainless steel wool. The wool wrapped portion is then sandwiched between tuning plates, which may also be stainless steel, by means of clamping screws which may be adjusted to change the clamping force of the sandwiched assembly along the waveguide section. The plates are preformed along their length in a sinusoidally bent pattern with a period approximately equal to the acoustic wavelength which is to be damped. The bent pattern of the opposing plates are in phase along their length relative to their sinusoidal patterns so that as the clamping screws are tightened a bending stress is applied to the waveguide at 180.degree. intervals along the damping section to oppose the acoustic wave motions in the waveguide and provide good coupling of the wool to the guide. The damper is tuned by selectively tightening the clamping screws while monitoring the amplitude of the acoustic waves launched in the waveguide. It may be selectively tuned to damp particular acoustic wave modes (torsional or extensional, for example) and/or frequencies while allowing others to pass unattenuated.
Rogers, Samuel C. (Knoxville, TN)
Apparatus for separating particles utilizing engineered acoustic contrast capture particles
An apparatus for separating particles from a medium includes a capillary defining a flow path therein that is in fluid communication with a medium source. The medium source includes engineered acoustic contrast capture particle having a predetermined acoustic contrast. The apparatus includes a vibration generator that is operable to produce at least one acoustic field within the flow path. The acoustic field produces a force potential minima for positive acoustic contrast particles and a force potential minima for negative acoustic contrast particles in the flow path and drives the engineered acoustic contrast capture particles to either the force potential minima for positive acoustic contrast particles or the force potential minima for negative acoustic contrast particles.
Kaduchak, Gregory (Los Alamos, NM); Ward, Michael D. (Los Alamos, NM)
Proceedings of the 11th European Conference on Underwater Acoustics ACHIEVABLE RATES OF UNDERWATER ACOUSTIC OFDM
Proceedings of the 11th European Conference on Underwater Acoustics ACHIEVABLE RATES OF UNDERWATER-Telecom, Telecom Bretagne, UMR CNRS 6285 Lab-STICC, Ueb, Brest, France J.-M. Passerieux Thales Underwater Systems maintaining acceptable data rates, remains one of the major difficulty faced by underwater acoustic
Paris-Sud XI, Université de
Current Titles
This booklet is published for those interested in current research being conducted at the National Center for Electron Microscopy. The NCEM is a DOE-designated national user facility and is available at no charge to qualified researchers. Access is controlled by an external steering committee. Interested researchers may contact Jane Cavlina, Administrator, at 510/486-6036.
Method and apparatus of spectro-acoustically enhanced ultrasonic detection for diagnostics
An apparatus for detecting a discontinuity in a material includes a source of electromagnetic radiation has a wavelength and an intensity sufficient to induce an enhancement in contrast between a manifestation of an acoustic property in the material and of the acoustic property in the discontinuity, as compared to when the material is not irradiated by the electromagnetic radiation. An acoustic emitter directs acoustic waves to the discontinuity in the material. The acoustic waves have a sensitivity to the acoustic property. An acoustic receiver receives the acoustic waves generated by the acoustic emitter after the acoustic waves have interacted with the material and the discontinuity. The acoustic receiver also generates a signal representative of the acoustic waves received by the acoustic receiver. A processor, in communication with the acoustic receiver and responsive to the signal generated by the acoustic receiver, is programmed to generate informational output about the discontinuity based on the signal generated by the acoustic receiver.
Vo-Dinh, Tuan (Knoxville, TN); Norton, Stephen J. (Raleigh, NC)
Imaging of Acoustic Waves in Sand
There is considerable interest in detecting objects such as landmines shallowly buried in loose earth or sand. Various techniques involving microwave, acoustic, thermal and magnetic sensors have been used to detect such objects. Acoustic and microwave sensors have shown promise, especially if used together. In most cases, the sensor package is scanned over an area to eventually build up an image or map of anomalies. We are proposing an alternate, acoustic method that directly provides an image of acoustic waves in sand or soil, and their interaction with buried objects. The INEEL Laser Ultrasonic Camera utilizes dynamic holography within photorefractive recording materials. This permits one to image and demodulate acoustic waves on surfaces in real time, without scanning. A video image is produced where intensity is directly and linearly proportional to surface motion. Both specular and diffusely reflecting surfaces can be accomodated and surface motion as small as 0.1 nm can be quantitatively detected. This system was used to directly image acoustic surface waves in sand as well as in solid objects. Waves as frequencies of 16 kHz were generated using modified acoustic speakers. These waves were directed through sand toward partially buried objects. The sand container was not on a vibration isolation table, but sat on the lab floor. Interaction of wavefronts with buried objects showed reflection, diffraction and interference effects that could provide clues to location and characteristics of buried objects. Although results are preliminary, success in this effort suggests that this method could be applied to detection of buried landmines or other near-surface items such as pipes and tanks.
Deason, Vance Albert; Telschow, Kenneth Louis; Watson, Scott Marshall
Current Status
Current Status Current Status > Content on this page requires a newer version of Adobe Flash Player. Get Adobe Flash player July 31, 1942 The Army Corp of Engineers leases 1,025 acres of the Cook County Forest Preserve to build a research facility. November 1942 Under the direction of Enrico Fermi, a group of scientists at the University of Chicago begin building Chicago Pile-1 (CP-1). Security and secracy were essential. December 2, 1942 Enrico Fermi's team creates the world's first self-sustaining nuclear chain reaction using the CP-1 reactor under Stagg Field at the University of Chicago. CP-1 1943 The experiments under Stagg Field shut down, and the scientists move to a 19 acre section of the leased forest preserve, known as Site A. CP-1 is reconstructed and modified at Site A and renamed Chicago Pile 2 (CP-2).
Dual excitation acoustic paramagnetic logging tool
New methods and apparatus are disclosed which allow measurement of the presence of oil and water in geological formations using a new physical effect called the Acoustic Paramagnetic Logging Effect (APLE). The presence of petroleum in formation causes a slight increase in the earth's magnetic field in the vicinity of the reservoir. This is the phenomena of paramagnetism. Application of an acoustic source to a geological formation at the Larmor frequency of the nucleons present causes the paramagnetism of the formation to disappear. This results in a decrease in the earth's magnetic field in the vicinity of the oil bearing formation. Repetitively frequency sweeping the acoustic source through the Larmor frequency of the nucleons present (approx. 2 kHz) causes an amplitude modulation of the earth's magnetic field which is a consequence of the APLE. The amplitude modulation of the earth's magnetic field is measured with an induction coil gradiometer and provides a direct measure of the amount of oil and water in the excitation zone of the formation. The phase of the signal is used to infer the longitudinal relaxation times of the fluids present, which results in the ability in general to separate oil and water and to measure the viscosity of the oil present. Such measurements may be performed in open boreholes and in cased well bores. The Dual Excitation Acoustic Paramagnetic Logging Tool employing two acoustic sources is also described. 6 figs.
Vail, W.B. III.
New methods and apparatus are disclosed which allow measurement of the presence of oil and water in gelogical formations using a new physical effect called the Acoustic Paramagnetic Logging Effect (APLE). The presence of petroleum in formation causes a slight increase in the earth's magnetic field in the vicinity of the reservoir. This is the phenomena of paramagnetism. Application of an acoustic source to a geological formation at the Larmor frequency of the nucleous present causes the paramagnetism of the formation to disappear. This results in a decrease in the earth's magnetic field in the vicinity of the oil bearing formation. Repetitively frequency sweeping the acoustic source through the Larmor frequency of the nucleons present (approx. 2 kHz) causes an amplitude modulation of the earth's magnetic field which is a consequence of the APLE. The amplitude modulation of the earth's magnetic field is measured with an induction coil gradiometer and provides a direct measure of the amount of oil and water in the excitation zone of the formation. The phase of the signal is used to infer the longitudinal relaxation times of the fluids present, which results in the ability in general to separate oil and water and to measure the viscosity of the oil present. Such measurements may be preformed in open boreholes and in cased well bores. The Dual Excitation Acoustic Paramagnetic Logging Tool employing two acoustic sources is also described.
13.853 Computational Ocean Acoustics, Spring 2003
Wave equations for fluid and visco-elastic media. Wave-theory formulations of acoustic source radiation and seismo-acoustic propagation in stratified ocean waveguides. Wavenumber Integration and Normal Mode methods for ...
Schmidt, Henrik
Development and Testing of the MIT Acoustic Levitation Test Facilities
Two acoustic levitation test facilities have been developed for cloud physics experimentation. These facilities utilize acoustic standing wave energy to suspend both solid and liquid objects in a contact-free environment. In the still-air ...
Victor D. Lupi; R. John Hansman
Ultrafast photo-acoustic spectroscopy of super-cooled liquids
Picosecond laser ultrasonic techniques for acoustic wave generation and detection were adapted to probe longitudinal and transverse acoustic waves in liquids at gigahertz frequencies. The experimental effort was designed ...
Klieber, Christoph
Acoustic measurement of the Deepwater Horizon Macondo well flow rate
On May 31, 2010, a direct acoustic measurement method was used to quantify fluid leakage rate from the Deepwater Horizon Macondo well prior to removal of its broken riser. This method utilized an acoustic imaging sonar and ...
Camilli, Richard
Spatiotemporal processing and time-reversal for underwater acoustic communications
High-rate underwater acoustic communication can be achieved using transmitter/receiver arrays. Underwater acoustic channels can be characterized as rapidly time-varying systems that suffer severe Inter Symbol Interferences ...
Wang, Daniel Y
Effects of Hydrogen on the Thermo-Acoustics Coupling Mechanisms...
on the Thermo-Acoustics Coupling Mechanisms of Low-Swirl Injector Flames in a Model Gas Turbine Combustor Title Effects of Hydrogen on the Thermo-Acoustics Coupling...
SPARSE UNDERWATER ACOUSTIC IMAGING: A CASE STUDY Nikolaos Stefanakis
SPARSE UNDERWATER ACOUSTIC IMAGING: A CASE STUDY Nikolaos Stefanakis , Jacques Marchal , Valentin de Beaulieu 35042 Rennes Cedex, France ABSTRACT Underwater acoustic imaging is traditionally 3D underwater imaging using a newly built flexible-configuration sonar device. The computational
Cooperative Schemes for Underwater Acoustic Communications (AQU 3)
Cooperative Schemes for Underwater Acoustic CommunicationsIntroduction: Underwater Cooperative CommunicationsMotivation Traditional underwater communications Used for
Madhavan Vajapeyam; Satish Vedantam; Urbashi Mitra
NASA Glenn Research Center Acoustical Testing Laboratory: Five year retrospective
In the five years since the NASA Glenn Research Center Acoustical Testing Laboratory (ATL) opened its doors in September
Continental Slope Flow Northeast of Taiwan
Hydrographic observations and current measurements with a Shipboard Acoustic Doppler Current Profiler over the continental shelf–slope junction northeast of Taiwan during 10–17 August 1994 allow the construction of the mesoscale flow pattern ...
T. Y. Tang; Y. Hsueh; Y. J. Yang; J. C. Ma
Observed Oceanic Response over the Upper Continental Slope and Outer Shelf during Hurricane Ivan
Hurricane Ivan passed directly over an array of 14 acoustic Doppler current profilers deployed along the outer continental shelf and upper slope in the northeastern Gulf of Mexico. Currents in excess of 200 cm s?1 were generated during this ...
W. J. Teague; E. Jarosz; D. W. Wang; D. A. Mitchell
Assimilation of Ship-Mounted ADCP Data for Barotropic Tides: Application to the Ross Sea
The application of a generalized inverse approach for assimilating vessel-mounted acoustic Doppler current profiler (VM-ADCP) data into numerical solutions of barotropic tides is described. The derived estimates of tidal currents can be used to ...
S. Y. Erofeeva; Laurie Padman; Gary Egbert
The Shallow and Deep Western Boundary Circulation of the South Atlantic at 5°–11°S
Repeated shipboard observation sections across the boundary flow off northeastern Brazil as well as acoustic Doppler current profiler (ADCP) and current-meter records from a moored boundary array deployed during 2000–04 near 11°S are analyzed ...
Friedrich A. Schott; Marcus Dengler; Rainer Zantopp; Lothar Stramma; Jürgen Fischer; Peter Brandt
Near-Surface Frontal Zone Trapping and Deep Upward Propagation of Internal Wave Energy in the Japan/East Sea
The full-depth current structure in the Japan/East Sea was investigated using direct velocity measurements performed with lowered and shipboard acoustic current Doppler profilers. Rotary spectral analysis was used to investigate the three-...
Andrey Y. Shcherbina; Lynne D. Talley; Eric Firing; Peter Hacker
The Finescale Response of Lowered ADCP Velocity Profiles
Lowered acoustic Doppler current profiler (LADCP) velocity profiles are compared with simultaneous higher-resolution expendable current profiler (XCP) profiles to determine the lowered ADCP's response at short wavelengths. Although lowered ADCP ...
Kurt Polzin; Eric Kunze; Jules Hummon; Eric Firing
Subinertial Slope-Trapped Waves in the Northeastern Gulf of Mexico
Current velocity from moored arrays of acoustic Doppler current profilers (ADCPs) deployed on the outer shelf and slope, south of Mobile Bay in the northeastern Gulf of Mexico, shows evidence of alongslope, generally westward-propagating ...
Z. R. Hallock; W. J. Teague; E. Jarosz
A High Resolution Hydrometer Phase Classifier Based on Analysis of Cloud Radar Doppler Spectra.
The lifecycle and radiative properties of clouds are highly sensitive to the phase of their hydrometeors (i.e., liquid or ice). Knowledge of cloud phase is essential for specifying the optical properties of clouds, or else, large errors can be introduced in the calculation of the cloud radiative fluxes. Current parameterizations of cloud water partition in liquid and ice based on temperature are characterized by large uncertainty (Curry et al., 1996; Hobbs and Rangno, 1998; Intriery et al., 2002). This is particularly important in high geographical latitudes and temperature ranges where both liquid droplets and ice crystal phases can exist (mixed-phase cloud). The mixture of phases has a large effect on cloud radiative properties, and the parameterization of mixed-phase clouds has a large impact on climate simulations (e.g., Gregory and Morris, 1996). Furthermore, the presence of both ice and liquid affects the macroscopic properties of clouds, including their propensity to precipitate. Despite their importance, mixed-phase clouds are severely understudied compared to the arguably simpler single-phase clouds. In-situ measurements in mixed-phase clouds are hindered due to aircraft icing, difficulties distinguishing hydrometeor phase, and discrepancies in methods for deriving physical quantities (Wendisch et al. 1996, Lawson et al. 2001). Satellite-based retrievals of cloud phase in high latitudes are often hindered by the highly reflecting ice-covered ground and persistent temperature inversions. From the ground, the retrieval of mixed-phase cloud properties has been the subject of extensive research over the past 20 years using polarization lidars (e.g., Sassen et al. 1990), dual radar wavelengths (e.g., Gosset and Sauvageot 1992; Sekelsky and McIntosh, 1996), and recently radar Doppler spectra (Shupe et al. 2004). Millimeter-wavelength radars have substantially improved our ability to observe non-precipitating clouds (Kollias et al., 2007) due to their excellent sensitivity that enables the detection of thin cloud layers and their ability to penetrate several non-precipitating cloud layers. However, in mixed-phase clouds conditions, the observed Doppler moments are dominated by the highly reflecting ice crystals and thus can not be used to identify the cloud phase. This limits our ability to identify the spatial distribution of cloud phase and our ability to identify the conditions under which mixed-phase clouds form.
Luke,E.; Kollias, P.
Underwater acoustic imaging: physically-motivated sparse models
Underwater acoustic imaging: physically-motivated sparse models and validation on real data N hal-00677287,version1-4Jun2012 #12;Underwater acoustic imaging (UWA)hal-00677287,version1-4Jun2012 #12;Underwater acoustic imaging: direct problem Successive emission sequences, or pings, indexed by p. ep
Proceedings of the 11 European Conference on Underwater Acoustics
Proceedings of the 11 th European Conference on Underwater Acoustics INCOHERENT CHANGE DETECTION on Underwater Acoustics images. This allows performing a segmentation of the master image at the coarser stage,version1-7Sep2012 #12;Proceedings of the 11 th European Conference on Underwater Acoustics The idea
Electron-acoustic vortices in multicomponent magnetoplasma
Linear and nonlinear properties of electron-acoustic waves in a multicomponent magnetoplasma comprising of cold and beam electrons and two species of thermal unmagnetized ions are investigated here. It is found that the electron beam velocity, electron Debye length, electron Larmor radius, and concentration of the cold and beam electrons affect the linear dispersion characteristics of electron-acoustic wave. It is also found that such a multicomponent plasma admits dipolar and vortex street type structures for the normalized electrostatic potential PHIgeomagnetic tail, etc. is also pointed out.
Haque, Q. [Theoretical Plasma Physics Division, PINSTECH, P. O. Nilore, Islamabad 45320 (Pakistan); Mirza, Arshad M. [Department of Physics, Theoretical Plasma Physics Group, Quaid-i-Azam University, Islamabad 45320 (Pakistan); Nargis, Shahida [Department of Mathematics, Quaid-i-Azam University, Islamabad 45320 (Pakistan)
Point interactions in acoustics: one dimensional models
A one dimensional system made up of a compressible fluid and several mechanical oscillators, coupled to the acoustic field in the fluid, is analyzed for different settings of the oscillators array. The dynamical models are formulated in terms of singular perturbations of the decoupled dynamics of the acoustic field and the mechanical oscillators. Detailed spectral properties of the generators of the dynamics are given for each model we consider. In the case of a periodic array of mechanical oscillators it is shown that the energy spectrum presents a band structure.
C. Cacciapuoti; R. Figari; A. Posilicano
Ion acoustic shock waves in degenerate plasmas
Korteweg de Vries Burgers equation for negative ion degenerate dissipative plasma has been derived using reductive perturbation technique. The quantum hydrodynamic model is used to study the quantum ion acoustic shock waves. The effects of different parameters on quantum ion acoustic shock waves are studied. It is found that quantum parameter, electrons Fermi temperature, temperature of positive and negative ions, mass ratio of positive to negative ions, viscosity, and density ratio have significant impact on the shock wave structure in negative ion degenerate plasma.
Akhtar, N. [Theoretical Plasma Physics Division, PINSTECH, Nilore, Islamabad 44000 Pakistan (Pakistan); Hussain, S. [Theoretical Plasma Physics Division, PINSTECH, Nilore, Islamabad 44000 Pakistan (Pakistan); Department of Physics and Applied Mathematics, PIEAS, Nilore, Islamabad 44000 Pakistan (Pakistan)
Acoustic microscope surface inspection system and method
An acoustic microscope surface inspection system and method in which pulses of high frequency electrical energy are applied to a transducer which forms and focuses acoustic energy onto a selected location on the surface of an object and receives energy from the location and generates electrical pulses. The phase of the high frequency electrical signal pulses are stepped with respected to the phase of a reference signal at said location. An output signal is generated which is indicative of the surface of said selected location. The object is scanned to provide output signals representative of the surface at a plurality of surface locations.
Khuri-Yakub, Butrus T. (Palo Alto, CA); Parent, Philippe (Chilly-Mazarin, FR); Reinholdtsen, Paul A. (Seattle, WA)
Acoustic Propagation Prediction in Shallow Water
An acoustic propagation experiment was conducted on 17 May 2000 in a shallow water site off the Perth metropolitan coast with the view of obtaining reflection and refraction data to contribute to developing a geoacoustic model of the area. The site proposed has constant bathymetry, though the geological properties of the site are not well known. The experiment used two hydrophones, one situated mid-water and the other moored to the seabed to explore the possibility of receiving head waves. The acoustic sources used were a 20-cui air gun and imploding sources comprising 60W and 75W light globes and purpose built evacuated spheres.
Justin Hoffman John; John D. Penrose; Darryl R. Mcmahon
Energy Currents
1 1 Energy Currents LBL Scientist Joins Clinton Administration Art Rosenfeld Art Rosenfeld, former head of LBL's Center for Building Science, has been named a senior advisor in the U.S. Department of Energy, serving under Assistant Secretary for Energy Efficiency and Renewable Energy Christine Ervin. His appointment began July 1. In Washington, Rosenfeld will sit on President Clinton's National Science and Technology Council. He will also serve as national spokesperson for the Administration's "Cool Communities" program and will help steer through the political process a proposed new "government-sponsored enterprise"- called EFFIE MAE for Energy Efficiency Mortgage and Loan Agency-that would guarantee loans for retrofitting energy-inefficient public buildings.
7 7 Energy Currents Survey Result Our thanks to all of you who responded to our reader survey. We were pleased that many of you find this a useful publication. Your opinions will help us improve it further. The CBS News' readers include a variety of professions. 17% of respondents were consultants, 15% were engineers, 11% were teachers, 11% were scientists, 10% were program managers. The remainder included contractors, designers, marketing professionals policy analysts, journalists and others. Ranked according to highest response first, the majority of readers work in education, various levels of government, utilities, non-profit organizations, and a variety of private concerns. A surprisingly large number, 52% of the respondents, are Internet users and 23% have browsed the World Wide Web. 8% have browsed the Center's Web site
Chirp-Induced Bias in Velocity Measurements by a Coherent Doppler CO2 Lidar
Radial wind velocity measurements by a pulsed CO2 Doppler lidar may be biased even in stationary atmospheric conditions. The authors show it is due to random speckle fluctuations of the backscattered signal and is related to the dissymmetry of ...
Alain M. Dabas; Philippe Drobinski; Pierre H. Flamant
A Comparison of Tornado Warning Lead Times with and without NEXRAD Doppler Radar
The installation of the network of NEXRAD (Next Generation Weather Radar) WSR-88D (Weather Surveillance Radar—1988 Doppler) radars has been an ongoing process for more than three years. An assessment is made on how these radars and related ...
Paul Bieringer; Peter S. Ray
Simulation of Coherent Doppler Lidar Performance for Space-Based Platforms
The performance of coherent Doppler lidar velocity estimates for a space-based platform are produced using computer simulations of raw data and statistical descriptions of the resulting velocity estimates. The random spatial variability of the ...
Microburst Wind Structure and Evaluation of Doppler Radar for Airport Wind Shear Detection
Doppler weather radar data from the Joint Airport Weather Studies (JAWS) Project are used to determine the horizontal and vertical structure of airflow within microbursts. Typically, the associated downdraft is about 1 km wide and begins to ...
James W. Wilson; Rita D. Roberts; Cathy Kessinger; John McCarthy
Wind Synthesis and Quality Control of Multiple-Doppler-Derived Horizontal Wind Fields
Horizontal wind vector fields can be measured in real time by a bistatic Doppler radar network and can be applied directly for hazard warnings and weather surveillance. Most applications, however, especially for meteorological research and ...
Katja Friedrich; Martin Hagen
Cell Development and Merger in an Illinois Thunderstorm Observed by Doppler Radar
A reflectivity and triple-Doppler radar study of the development of several cells and their successive union within a nonsevere thunderstorm is presented. Two characteristic separations were found between the newly formed cells and the parent ...
Nancy E. Westcott; Patrick C. Kennedy
Horizontal Divergence and Vertical Velocity Retrievals from Doppler Radar and Wind Profiler Observations
Vertical motion profiles can be diagnosed with the mass continuity equation using horizontal divergence fields derived from various single-Doppler radar techniques such as EVAD (extended velocity-azimuth display), CEVAD (concurrent extended ...
Robert Cifelli; Steven A. Rutledge; Dennis J. Boccippio; Thomas Matejka
High-Resolution Doppler Lidar Observations of Transient Downslope Flows and Rotors
The authors present observations of the temporal evolution of downslope windstorms with rotors and internal hydraulic jumps of unprecedented detail and spatiotemporal coverage. The observations were carried out by means of a coherent Doppler lidar ...
Christian Kühnlein; Andreas Dörnbrack; Martin Weissmann
Investigation of the Turbulent Structure of a Cloud-Capped Mixed Layer Using Doppler Radar
A new method for retrieving air velocity fluctuations in the cloud-capped boundary layer (BL) using radar reflectivity and the Doppler velocity fields is proposed. The method was developed on the basis of data obtained by the Transportable ...
M. Pinsky; O. Krasnov; H. W. J. Russchenberg; A. Khain
One-Year Operational Measurements with a Sonic Anemometer–Thermometer and a Doppler Sodar
A Doppler sodar and an ultrasonic anemometer–thermometer, which are operated continuously at a nuclear research center in Germany, are described. Mean values and second moments including turbulent surface fluxes recorded over 1 yr are analyzed in ...
Gerhard Peters; Bernd Fischer; Hans Jürgen Kirtzel
Remote Measurement of Turbulent Wind Spectra by Heterodyne DopplerLidar Technique
Heterodyne Doppler lidars (HDLs) are used to monitor atmospheric wind field and wind turbulence at remote distance. This last application calls for the derivation of wind spectra, which can be characterized by the dissipation rate and the ?-...
Philippe Drobinski; Alain M. Dabas; Pierre H. Flamant
Doppler Lidar Measurements of Turbulent Structure Function over an Urban Area
Analysis of radial wind velocity data from the Salford pulsed Doppler infrared lidar is used to calculate turbulent spectral statistics over the city of Salford in the United Kingdom. The results presented here, first, outline the error ...
F. Davies; C. G. Collier; G. N. Pearson; K. E. Bozier
High-Resolution Doppler Lidar for Boundary Layer and Cloud Research
The high-resolution Doppler lidar (HRDL) was developed to provide higher spatial, temporal, and velocity resolution and more reliable performance than was previously obtainable with CO2-laser-based technology. The improved performance is needed ...
Christian J. Grund; Robert M. Banta; Joanne L. George; James N. Howell; Madison J. Post; Ronald A. Richter; Ann M. Weickmann
An Example of the Use of Mobile, Doppler Radar Data for Tornado Verification
On 16 May 2003, two ground-based, mobile, Doppler radars scanned a potentially tornadic supercell in the Texas Panhandle intermittently from 0200 to 0330 UTC. The storm likely was tornadic, but because it was dark, visual confirmation of any ...
Michael M. French; Howard B. Bluestein; Louis J. Wicker; David C. Dowell; Matthew R. Kramar
Interpretation of Doppler Weather Radar Displays of Midlatitude Mesoscale Convective Systems
The utility of color displays of Doppler-radar data in revealing real-time kinematic information has been demonstrated in past studies, especially for extratropical cyclones and severe thunderstorms. Such displays can also indicate aspects of the ...
Robert A. Houze Jr.; M. I. Biggerstaff; S. A. Rutledge; B. F. Smull
A Look Back on Two Decades of Doppler Sodar Comparison Studies
This paper is a compilation of the results obtained from various Doppler sodar comparison experiments conducted over the last 20 years. These studies have attempted to quantify the uncertainties in sodar-derived values of the horizontal wind ...
Gennaro H. Crescenti
The Life Cycle of Thunderstorm Gust Fronts as Viewed with Doppler Radar and Rawinsonde Data
This paper presents the time-dependent analysis of the thunderstorm gust front with the use of Project NIMROD data. RHI cross sections of reflectivity and Doppler velocity are constructed to determine the entire vertical structure. The life cycle ...
Roger M. Wakimoto
What Should Be Considered When Simulating Doppler Velocities Measured by Ground-Based Weather Radars?
A sophisticated and flexible simulator of Doppler velocities measured by ground-based weather radars is appended to a high-resolution nonhydrostatic atmospheric model. Sensitivity experiments are conducted by using different configurations for ...
Olivier Caumont; Véronique Ducrocq
Accuracy of Wind Fields Observed by a Bistatic Doppler Radar Network
The accuracy of wind vectors derived from bistatic dual-Doppler synthesis was investigated. The investigation was based on mathematical examinations and observation data analyses in both convective and stratiform cases. Accurate wind vectors were ...
Shinsuke Satoh; Joshua Wurman
Clutter Filtering and Spectral Moment Estimation for Doppler Weather Radars Using Staggered Pulse Repetition Time (PRT)
In this paper, a new algorithm for the estimation of spectral parameters from the signal time series, collected using the staggered pulse repetition time (PRT) transmission in a Doppler weather radar, is presented. The algorithm uses the Fourier ...
M. Sachidananda; D. S. Zrni?
Investigation of Non-Gaussian Doppler Spectra Observed by Weather Radar in a Tornadic Supercell
Radar Doppler spectra that deviate from a Gaussian shape were observed from a tornadic supercell on 10 May 2003, exhibiting features such as a dual peak, flat top, and wide skirt in the nontornadic region. Motivated by these observations, a ...
Tian-You Yu; Ricardo Reinoso Rondinel; Robert D. Palmer
Determination of Winds from Balloon Tracking with a Doppler Weather Radar
Computer programs for antenna control and data processing were prepared and interfacing was fabricated to enable the Doppler radar at Norman, Oklahoma, to track a reflectorized balloon, and define winds in the layer through which the balloon ...
Dúsan S. Zrni?; Dale Sirmans; Edwin Kessler
The Influence of Airborne Doppler Radar Data Quality on Numerical Simulations of a Tropical Cyclone
The impact of airborne Doppler radar data assimilation on improving numerical simulations of tropical cyclones (TCs) has been well recognized. However, the influence of radar data quality on the numerical simulation of tropical cyclones has not ...
Lei Zhang; Zhaoxia Pu; Wen-Chau Lee; Qingyun Zhao
Terminal Doppler Weather Radar Observation of Atmospheric Flow over Complex Terrain during Tropical Cyclone Passages
A Terminal Doppler Weather Radar (TDWR) started operation in Hong Kong, China, in 1997 for monitoring wind shear associated with thunderstorms affecting the Hong Kong International Airport. The airport was built on land reclaimed from the sea and ...
C. M. Shun; S. Y. Lau; O. S. M. Lee
Case Study of a Hailstorm in Colorado. Part III: Airflow From Triple-Doppler Measurements
Triple-Doppler measurements are presented for a hailstorm of moderate intensity that occurred over the High plains of northeastern Colorado, and an airflow model is synthesized. The storm had a number of persistent features similar to previous ...
G. Brant Foote; Harold W. Frank
Maximum Likelihood Estimates of Vortex Parameters from Simulated Coherent Doppler Lidar Data
The performance of pulsed coherent Doppler lidar in estimating aircraft trailing wake vortices by scanning across the aircraft flight track is evaluated using Monte Carlo lidar simulations of a simple vortex pair in both a nonturbulent and ...
Rod Frehlich; Robert Sharman
An Improved Time Interpolation for Three-Dimensional Doppler Wind Analysis
A temporal interpolation is required for three-dimensional Doppler wind analysis when the precise measurement time is counted for each radar beam position. The time interpolation is traditionally done by a linear scheme either in the measurement ...
Shun Liu; Chongjian Qiu; Qin Xu; Pengfei Zhang
Extended Velocity Track Display (EVTD): An Improved Processing Method for Doppler Radar Observations of Tropical Cyclones
The authors present an improved version of the velocity track display (VTD) method, proposed by Lee et al., to deduce the primary vortex circulation in hurricanes from airborne Doppler radar data obtained during straightline legs through the ...
Frank Roux; Frank D. Marks Jr.
The Measurement of Doppler Wind Fields with Fast Scanning Radars: Signal Processing Techniques
This paper discusses signal processing techniques being developed for making Doppler wind velocity measurements using airport surveillance radars. Techniques are presented and evaluated for velocity estimation using fast-rotating radars. In ...
John R. Anderson
Correction of Amplitudes of Bragg Lines in the Sea Echo Doppler Spectrum of an Ocean Radar
Amplitudes of Bragg lines in the Doppler spectrum of high frequency or very high frequency (VHF) ocean radar sea echoes are important because they are used in normalizing the second-order scattering when calculating ocean wave spectra. These ...
Yukiharu Hisaki
An FPGA-Based Doppler Processor for a Spaceborne Precipitation Radar
Measurement of precipitation Doppler velocity by spaceborne radar is complicated by the large velocity of the satellite platform. Even if successive pulses are well correlated, the velocity measurement may be biased if the precipitation target ...
S. L. Durden; M. A. Fischman; R. A. Johnson; A. J. Chu; M. N. Jourdan; S. Tanelli
Multiple-Doppler Radar Observations of the Evolution of Vorticity Extrema in a Convective Boundary Layer
Overdetermined, dual-Doppler wind syntheses are used to document the evolution, structure, and dynamics of vertical vorticity extrema observed in a convective boundary layer during the 12 June 2002 International H2O Project (IHOP) mission. ...
Paul Markowski; Christina Hannon
A Note on the Role of Mean Flows in Doppler-Shifted Frequencies
The purpose of this paper is to resolve a confusion that may arise from two quite distinct definitions of "Doppler shifts": both are used in the oceanographic literature but they are sometimes conflated. One refers to the difference in frequencies ...
Theo Gerkema; Leo R. M. Maas; Hans van Haren
Doppler Radar Study of the Trailing Anvil Region Associated with a Squall Line
The kinematic structure and reflectivity distribution within a region of widespread precipitation associated with a summertime midlatitude (Illinois) squall line, as revealed by an analysis of Doppler radar data, are presented and discussed. The ...
R. C. Srivastava; T. J. Matejka; T. J. Lorello
Triple-Doppler Analysis of a Discretely Propagating, Long-Lived, High Plains Squall Line
A nonsevere squall line that developed on 21 June 1993 along the northern foothills of the Colorado Rocky Mountains is analyzed using a series of triple-Doppler analyses. This squall line developed in a relatively dry environment characterized by ...
Rodney L. Grady; Johannes Verlinde
A Wintertime Gulf Coast Squall Line Observed by EDOP Airborne Doppler Radar
An extensive wintertime squall line on 13 January 1995 occurring along the U.S. Gulf of Mexico coastline is examined using airborne radar observations combined with conventional data analysis. Flight tracks with the ER-2 Doppler radar (EDOP) ...
G. M. Heymsfield; J. B. Halverson; I. J. Caylor
Evaluation of the Hurricane Research Division Doppler Radar Analysis Software Using Synthetic Data
The Hurricane Research Division Doppler radar analysis software provides three-dimensional analyses of the three wind components in tropical cyclones. Although this software has been used for over a decade, there has never been a complete and in-...
Sylvie Lorsolo; John Gamache; Altug Aksoy
Environmental Flow Impacts on Tropical Cyclone Structure Diagnosed from Airborne Doppler Radar Composites
Following a recent demonstration of multicase compositing of axisymmetric tropical cyclone (TC) structure derived from airborne Doppler radar measurements, the authors extend the analysis to the asymmetric structure using an unprecedented database ...
Paul D. Reasor; Robert Rogers; Sylvie Lorsolo
Improvement of Tornado Warnings by Doppler Radar Measurement of Mesocyclone Rotational Kinetic Energy
A significant improvement in the reliability and timeliness of tornado warnings can be achieved through quantitative measurement by Doppler radar of selected mesocyclone features. The mesocyclone, a midsize circulation found in some of the most ...
Ralph J. Donaldson Jr.; Paul R. Desrochers
Simulation of Coherent Doppler Lidar Performance in the Weak-Signal Regime
The performance of coherent Doppler lidar in the weak-signal regime is investigated by computer simulations of velocity estimators that accumulate the signal from N pulses of zero-mean complex Gaussian stationary lidar data described by a ...
A Triple-Doppler Radar Analysis of a Discretely Propagating Multicell Convective Storm
A triple-Doppler radar case study of a regularly propagating multicell convective storm has been performed. The motion of the storm, observed on 7 June 1978 during Project NIMROD, was somewhat unusual with cell translation and propagation ...
Robert E. Peterson Jr.
Recovery of Three-Dimensional Wind and Temperature Fields from Simulated Single-Doppler Radar Data
A method for recovering the full three-dimensional wind and temperature fields from single-Doppler radar data is developed and demonstrated. This method uses a dynamic model, and attempts to determine the initial conditions of the unobserved flow ...
Juanzhen Sun; Dawn W. Flicker; Douglas K. Lilly
Open-Channel Flow and Turbulence Measurement by High-Resolution Doppler Sonar
Measurements of water velocity and turbulence in a water flume using a Doppler sonar operating at 1 MHz are presented. Analysis of the results shows that the instrument qualifies as a very useful tool for nonintrusive and accurate measurement of ...
R. Lhermitte; U. Lemmin
Real-Time Retrieval of the Wind from Aliased Velocities Measured by Doppler Radars
Doppler radar measurements provide the radial wind within an unambiguous interval due to the limited value of the sampling frequency (pulse repetition frequency). Many algorithms have been developed to retrieve true wind velocities from measured ...
Pierre Tabary; Georges Scialom; Urs Germann
Airborne Doppler Lidar Investigation of Sea Surface Reflectance at a 355-nm Ultraviolet Wavelength
The analysis of the sea surface reflectance for different incidence angles based on observations of an airborne Doppler lidar at an ultraviolet wavelength of 355 nm is described. The results were compared to sea surface reflectance models, ...
Zhigang Li; Christian Lemmerz; Ulrike Paffrath; Oliver Reitebuch; Benjamin Witschas
Observations of a Tropical Thunderstorm Using a Vertically Pointing, Dual-Frequency, Collinear Beam Doppler Radar
This paper describes an investigation of a thunderstorm that occurred in the summer of 1991 over the National Astronomy and Ionosphere Center in Arecibo, Puerto Rico. Observations were made using collinear dual-wavelength Doppler radars, which ...
P. B. Chilson; C. W. Ulbrich; M. F. Larsen; P. Perillat; J. E. Keener
Significance of the Coupled Term in the Doppler Weather Radar Spectrum Width Equation
There is an additional zero mean random variable term that couples mean wind shear and turbulence in the Doppler radar spectrum width equation. This random variable, labeled the "coupled term," has been neglected heretofore in the literature. ...
Ming Fang; Richard J. Doviak; Bruce A. Albrecht
Polarization diversity for millimeter space-borne Doppler radars: an answer for observing deep convection?
Spaceborne Doppler radars have the potential to provide key missing observations of convective vertical air motions especially over the tropical oceans. Such measurements can improve our understanding of the role of tropical convection in vertical ...
Alessandro Battaglia; Simone Tanelli; Pavlos Kollias
An Atmospheric Solitary Gust Observed with a Doppler Radar, a Tall Tower and a Surface Network
Doppler radar and a 444 m tall instrumented tower provide a detailed view of the kinematic and thermodynamic structure of a solitary gust. A study of the data fields, and comparison with theoretical and laboratory work leads to the conclusion ...
Richard J. Doviak; Runsheng Ge
A Fuzzy Logic Method for Improved Moment Estimation from Doppler Spectra
A new method for estimating moments from wind measurement devices that measure Doppler spectra as a function of range is presented. Quite often the spectra are contaminated by a wide variety of sources, including (but not limited to) birds, ...
Larry B. Cornman; Robert K. Goodrich; Corinne S. Morse; Warner L. Ecklund
High-Resolution, Mobile Doppler Radar Observations of Cyclic Mesocyclogenesis in a Supercell
On 15 May 2003, two ground-based, mobile, Doppler radars scanned a supercell that moved through the Texas Panhandle and cyclically produced mesocyclones. The two radars collected data from the storm during a rapid cyclic mesocyclogenesis stage ...
Michael M. French; Howard B. Bluestein; David C. Dowell; Louis J. Wicker; Matthew R. Kramar; Andrew L. Pazmany
Least Squares Retrieval of Microburst Winds from Single-Doppler Radar Data
A least squares (LS) method is developed for retrieving low-altitude winds from single-Doppler radar scans. The method is tested with Denver airport microburst data and the results compared with the previously developed simple adjoint (SA) ...
Chong-Jian Qiu; Qin Xu
Systematic Phase Codes for Resolving Range Overlaid Signals in a Doppler Weather Radar
This paper deals with the recovery of Doppler velocities in the presence of range overlaid echoes. Transmitted pulses are phase shifted to tag the echoes from scatterers, which are separated by the unambiguous range. A new systematic phase code ...
M. Sachidananda; Dusan S. Zrnic
Effects of Radar Proximity on Single-Doppler Velocity Signatures of Axisymmetric Rotation and Divergence
Geometrical and mathematical relationships are developed to explain the variation with radar range of idealized single-Doppler velocity patterns of axisymmetric rotation and divergence regions. The velocity patterns become distorted as they ...
First Results of Experimental Tests of the Newly Developed NARL Phased-Array Doppler Sodar
A multifrequency phased-array Doppler sodar system has been installed recently at the National Atmospheric Research Laboratory (NARL) for the continuous observation of the lower atmosphere from near ground to the atmospheric boundary layer (ABL). ...
V. K. Anandan; M. Shravan Kumar; I. Srinivasa Rao
Semiempirical Model for the Reliability of a Matched Filter Frequency Estimator for Doppler Lidar
The author proposes a heuristic semiempirical model for predicting the reliability of a matched-filter frequency estimator applied to Doppler lidar signals. The model is tuned by a single coefficient ? empirically related to the ratio of the ...
Alain Dabas
Airflow and Precipitation Fields within Deep Alpine Valleys Observed by Airborne Doppler Radar
Although airborne Doppler radar is increasingly relied upon to provide detailed descriptions of mesoscale precipitation systems in remote and complex meteorological settings, the utility of these observations has often been limited by the ...
Olivier Bousquet; Bradley F. Smull
Retrieval of Atmospheric Parameters from Hydrometeor Backscatter Measured with Doppler Radar Profiler
The evaluation of backscatter spectra of clouds and precipitation measured with Doppler radar profilers allows the retrieval of a number of important atmospheric parameters. This retrieval leads to inaccurate results if vertical wind parameters ...
Dirk Klugmann
A Millimeter-Wavelength Dual-Polarization Doppler Radar for Cloud and Precipitation Studies
A pulse Doppler radar system operating at 35 GHz and having full polarization (linear and circular) diversity capability is described. Separate antennas are used for the transmitter and the receiver because this design approach allows better ...
F. Pasqualucci; B. W. Bartram; R. A. Kropfli; W. R. Moninger
Kinetic Energy Budgets of a Subtropical Squall Line Determined from TAMEX Dual-Doppler Measurements
Dual-Doppler data collected during the Taiwan Area Mesoscale Experiment (TAMEX) are used to study the kinetic energy balance of a subtropical squall line over the Taiwan Straits. Values of each term in the kinetic energy budget equation are ...
Yeong-Jer Lin; Hsi Shen; Robert W. Pasken
Separating Cloud and Drizzle Radar Moments during Precipitation Onset Using Doppler Spectra
The retrieval of cloud, drizzle, and turbulence parameters using radar Doppler spectra is challenged by the convolution of microphysical and dynamical influences and the overall uncertainty introduced by turbulence. A new technique that utilizes ...
Edward P. Luke; Pavlos Kollias
A Dual-Doppler Radar Study of an OK PRE-STORM Heat Burst Event
Doppler and conventional radar, surface mesonetwork, and sounding data are used to investigate heat bursts that accompanied a mesoscale convective system (MCS) that traversed the OK PRE-STORM (Oklahoma–Kansas Preliminary Regional Experiment for ...
Ben C. Bernstein; Richard H. Johnson
Considerations in Exploring Laboratory Tornadolike Vortices with a Laser Doppler Velocimeter
A laser Doppler velocimeter was used to collect datasets consisting of means and turbulence intensities of radial and tangential velocity components for two vortex morphologies within a Ward-type tornado vortex chamber. This paper focuses on ...
John T. Snow; Donald E. Lund
A Study of Embryo Production and Hail Growth Using Dual-Doppler and Multiparameter Radars
The origin and importance to embryo and hail production of a region of drops advected above the freezing level in the updraft of a severe Colorado hailstorm is examined using radar polarization measurements in conjunction with dual-Doppler and ...
John W. Conway; Dušan S. Zrni?
A Doppler Radar Emulator with an Application to the Detectability of Tornadic Signatures
A Doppler radar emulator was developed to simulate the expected mean returns from scanning radar, including pulse-to-pulse variability associated with changes in viewing angle and atmospheric structure. Based on the user's configuration, the ...
Ryan M. May; Michael I. Biggerstaff; Ming Xue
Eddy Dissipation Rates in Thunderstorms Estimated by Doppler Radar in Relation to Aircraft In Situ Measurements
High-resolution aircraft turbulence measurements, well coordinated with radar Doppler spectral width measurements, have been used to verify radar-estimated energy dissipation rates within thunderstorms anvils. The radar-estimated eddy dissipation ...
Peter Meischner; Robert Baumann; Hartmut Höller; Thomas Jank
Vector Winds from a Single-Transmitter Bistatic Dual-Doppler Radar Network
A bistatic dual-Doppler weather radar network consisting of only one transmitter and a nontransmitting, nonscanning, low-cost bistatic receiver was deployed in the Boulder, Colorado, area during 1993.
Joshua Wurman
Performance of Mean-Frequency Estimators for Doppler Radar and Lidar
The performance of mean-frequency estimators for Doppler radar and lidar measurements of winds is presented in terms of two basic parameters: ?, the ratio of the average signal energy per estimate to the spectral noise level; and ?, which is ...
R. G. Frehlich; M. J. Yadlowsky
Pressure and Buoyancy Fields Derived from Doppler Radar Data in a Tornadic Thunderstorm
A method for retrieval of pressure and buoyancy distributions in deep convection is applied to Doppler radar data collected at two analysis times during the tornadic Del City (Oklahoma) thunderstorm of 20 May 1977. Change of a previous version of ...
Carl E. Hane; Peter S. Ray
Influence of Wave Propagation on the Doppler Spreading of Atmospheric Gravity Waves
The "Doppler spread" theory of atmospheric gravity waves has developed rapidly in recent years, from an initial theory of wave spectra into a general parameterization of gravity wave effects for use in global models of the middle atmosphere. Yet ...
Stephen D. Eckermann
Doppler-Radar Measurements of Clear Air Atmospheric Turbulence at 1290 MHz
We present Doppler-radar observations for the refractivity turbulence structure constant CN2 obtained with the Chatanika Radar Facility, near Fairbanks, Alaska, during a 7-day observing period in October 1976.
Ben Balsley; Vern L. Peterson
The Down Upper Doppler and Electricity Experiment (DUNDEE): Overview and Preliminary Results
DUNDEE (Down Under Doppler and Electricity Experiment) is described. DUNDEE was carded out in the vicinity of Darwin, Northern Territory, Australia, during the wet seasons of November 1988 through February 1989, and November 1989 through February ...
Steven A. Rutledge; Earle R. Williams; Thomas D. Keenan
Recognizing Low-Altitude Wind Shear Hazards from Doppler Weather Radar: An Artificial Intelligence Approach
This paper describes an artificial intelligence-based approach for automated recognition of wind shear hazards. The design of a prototype system for recognizing low-attitude wind shear events from Doppler radar displays is presented. This system, ...
Steven D. Campbell; Stephen H. Olson
Doppler Radar and Lightning Network Observations of a Severe Outbreak of Tropical Cyclone Tornadoes
Data from a single Weather Surveillance Radar-1988 Doppler (WSR-88D) and the National Lightning Detection Network are used to examine the characteristics of the convective storms that produced a severe tornado outbreak, including three tornadoes ...
Eugene W. McCaul Jr.; Dennis E. Buechler; Steven J. Goodman; Michael Cammarata
A Solo-based automated quality control algorithm for airborne tail Doppler radar data
An automated quality control pre-processing algorithm for removing non-weather radar echoes in airborne Doppler radar data has been developed. This algorithm can significantly reduce the time and experience level required for interactive radar ...
Michael M. Bell; Wen-Chau Lee; Cory A. Wolff; Huaqing Cai
Characterization of Aircraft Wake Vortices by 2-?m Pulsed Doppler Lidar
The 2-?m pulsed Doppler lidar, already successfully used for wind and turbulence measurements, has been modified for long-range wake-vortex characterization. In particular, a four-stage data processing algorithm has been developed to achieve ...
Friedrich Köpp; Stephan Rahm; Igor Smalikho
Variational Analysis for Airborne Conically Scanned Doppler Lidar to Retrieve Mesoscale Wind Fields
An airborne pulsed Doppler lidar implementing a downlooking conical scan rotating around the vertical axis is under development. The information contained in the measured radial velocities is studied to assess the capacity to retrieve the 3D wind ...
Alain Dabas; Julie Périn; Pierre H. Flamant
Airborne Dual-Doppler Observations of an Intense Frontal System Approaching the Pacific Northwest Coast
Airborne Doppler radar data, collected off the Pacific Northwest coast by a NOAA WP-3D Orion aircraft over an 8-h period on 8 December 1993 during the Coastal Observations and Simulations with Topography experiment, reveal the mesoscale structure ...
Scott A. Braun; Robert A. Houze Jr.; Bradley F. Smull
Errors in Fixed and Moving Frame of References: Applications for Conventional and Doppler Radar Analysis
Procedures for the estimation and correction of advection effects with single and multiple conventional and Doppler radars are developed. In the case of scalars or Cartesian vectors, the essence of the method is finding a moving frame of ...
Tzvi Gal-Chen
The Structure of Thermals in Cumulus from Airborne Dual-Doppler Radar Observations
A newly developed technique for airborne dual-Doppler observations with the Wyoming Cloud Radar is used to characterize the velocity fields in vertical planes across cumulus turrets. The clouds sampled were continental in nature, with high bases (...
Rick Damiani; Gabor Vali; Samuel Haimov
Consistent Scale Interaction of Gravity Waves in the Doppler Spread Parameterization
The standard Doppler spread parameterization of gravity waves, which was proposed by C.-O. Hines and has been applied in a number of middle atmosphere general circulation models, is extended by the inclusion of all effects associated with ...
Erich Becker; Charles McLandress
Wind Speeds in Two Tornadic Storms and a Tornado, Deduced from Doppler Spectra
Doppler spectra of a tornado were collected with a radar having a large unambiguous velocity range, ±91 m s?1. Thus for the first time a presentation of nonaliased spectra was possible, showing direct measurement of radial velocities. By fitting ...
Dusan Zrnic; Michael Istok
Diagnosing Short Term Changes in Temperature. Profiles from Single Doppler Radar Data
A method is outlined to diagnose temperature changes aloft from single Doppler radar data and an initial radiosonde observation. One aim is to deduce changes in inversion strength and stability between synoptic soundings, which is particularly ...
R. M. Raibin
Doppler Lidar Estimation of Mixing Height Using Turbulence, Shear, and Aerosol Profiles
The concept of boundary layer mixing height for meteorology and air quality applications using lidar data is reviewed, and new algorithms for estimation of mixing heights from various types of lower-tropospheric coherent Doppler lidar ...
Sara C. Tucker; Christoph J. Senff; Ann M. Weickmann; W. Alan Brewer; Robert M. Banta; Scott P. Sandberg; Daniel C. Law; R. Michael Hardesty
Aspects of Convective Boundary Layer Turbulence Measured by a Dual-Doppler Lidar System
Special designed dual-Doppler setups can be used to retrieve simultaneous measurements of two wind components with high temporal resolution in several heights throughout the atmospheric boundary layer. During a field campaign in summer 2011, ...
Luisa Röhner; Katja Träumner
Volume Scanning Strategies for 3D Wind Retrieval from Dual-Doppler Lidar Measurements
Dual-Doppler lidar volume scans for 3D wind retrieval must accommodate the conflicting goals of dense spatial coverage and short scan duration. In this work, various scanning strategies are evaluated with semisynthetic wind fields from analytical ...
Susanne Drechsel; Georg J. Mayr; Michel Chong; Fotini K. Chow
Retrieving Winds in the Surface Layer over Land Using an Airborne Doppler Lidar
Airborne Doppler wind lidars are increasingly being used to measure winds in the lower atmosphere at higher spatial resolution than ever before. However, wind retrieval in the range gates closest to the earth's surface remains problematic. When a ...
K. S. Godwin; S. F. J. De Wekker; G. D. Emmitt
Retrieval of Urban Boundary Layer Structures from Doppler Lidar Data. Part I: Accuracy Assessment
Two coherent Doppler lidars from the U.S. Army Research Laboratory (ARL) and Arizona State University (ASU) were deployed in the Joint Urban 2003 atmospheric dispersion field experiment (JU2003) held in Oklahoma City, Oklahoma. The dual-lidar ...
Quanxin Xia; Ching-Long Lin; Ronald Calhoun; Rob K. Newsom
Removing the Laser-Chirp Influence from Coherent Doppler Lidar Datasets by Two-Dimensional Deconvolution
A chirped laser pulse can introduce artifacts into datasets of coherent Doppler wind lidars. At close vicinity of strong signal peaks undesired artificial velocities can be measured and continuous signals can be shifted by a constant factor. It is ...
Johannes Bühl; Ronny Engelmann; Albert Ansmann
Doppler-Radar Analysis of a Tropical Cyclone over Land: Hurricane Alicia (1983) in Oklahoma
The center of the circulation of the remains of Hurricane Alicia passed to the west of the National Severe Storms Laboratory's Doppler radar in Norman, Oklahoma on 19 August 1983. Three types of mesoscale precipitation were noted: the central ...
Howard B. Bluestein; Dean S. Hazen
Dual-Doppler Analysis of Winds and Vorticity Budget Terms near a Tornado
Three-dimensional dual-Doppler observations with unprecedented finescale spatial and temporal resolution are used to characterize the vector wind field and vorticity generation terms in and near a weak, short-lived tornado. The beam widths of the ...
Use of a Vertical Vorticity Equation in Variational Dual-Doppler Wind Analysis
The utility of the anelastic vertical vorticity equation in a weak-constraint (least squares error) variational dual-Doppler wind analysis procedure is explored. The analysis winds are obtained by minimizing a cost function accounting for the ...
Alan Shapiro; Corey K. Potvin; Jidong Gao
Effects of Wind Field Inhomogeneities on Doppler Beam Swinging Revealed by an Imaging Radar
In this work, the accuracy of the Doppler beam-swinging (DBS) technique for wind measurements is studied using an imaging radar—the turbulent eddy profiler (TEP) developed by the University of Massachusetts, with data collected in summer 2003. ...
B. L. Cheong; R. D. Palmer; T-Y. Yu; K-F. Yang; M. W. Hoffman; S. J. Frasier; F. J. Lopez-Dekker
Doppler Radar Analysis of the Northfield, Texas, Tornado of 25 May 1994
A large tornado was observed near Northfield, Texas, on 25 May 1994 during the Verification of the Origins of Rotation in Tornadoes Experiment (VORTEX). An analysis of the tornado and its parent storm is discussed. Doppler wind velocity spectra ...
Howard B. Bluestein; Wesley P. Unruh; David C. Dowell; Todd A. Hutchinson; Todd M. Crawford; Andrew C. Wood; Herbert Stein
Acoustic emission: flaw relationship for inservice monitoring of nuclear reactor pressure boundaries. [PWR; BWR
The objective of the acoustic emission (AE)/flaw characterization program is to provide an experimental feasibility evaluation of using the AE method on a continuous basis (during operation and during hydrotest) to detect and analyze flaw growth in reactor pressure vessels and primary piping. This effort is based on the philosophy that AE shows demonstrated capability for being a valuable addition to current nondestructive inspection (NDI) methods with unique capability for continuous monitoring, high sensitivity and remote flaw location.
Not Available
The Acoustic Properties of Different Noise Sources
This paper discusses a method to find the acoustic properties of different types of background noise: highway, airport, subway, restaurant, rain, inside a car, and inside a train. Four parameters are calculated using the Auto Correlation Function (ACF). ... Keywords: Environmental noise, noise classification
Jidong Yang; Buket D. Barkana
Uncanny soundscapes: Towards an inoperative acoustic community
Drawing on field research carried out in the abandoned villages of the Ara Valley, this article seeks to readdress notions of acoustic community and communication in terms of a 'haptic aurality' in which listening, as a mode of touch, approximates a ...
Iain Foreman
Cross-Dipole Acoustic Log | Open Energy Information
Cross-Dipole Acoustic Log Cross-Dipole Acoustic Log Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Cross-Dipole Acoustic Log Details Activities (1) Areas (1) Regions (0) NEPA(0) Exploration Technique Information Exploration Group: Downhole Techniques Exploration Sub Group: Well Log Techniques Parent Exploration Technique: Acoustic Logs Information Provided by Technique Lithology: Stratigraphic/Structural: Rock stress and fracture analysis Hydrological: Use for fracture identification in open and cased holes. Also used for evaluating hydro fracturing/well stimulation effectiveness. Thermal: Dictionary.png Cross-Dipole Acoustic Log: An acoustic logging technique where the acoustic transmitter and receivers are lowered down hole and waveforms that travel through the well mud,
Acoustic data transmission through a drillstring
A method and apparatus for acoustically transmitting data along a drillstring are presented. In accordance with one embodiment of the present invention, acoustic data signals are conditioned to counteract distortions caused by the drillstring. Preferably, this conditioning step comprises multiplying each frequency component of the data signal by exp ([minus]ikL) where L is the transmission length of the drillstring, k is the wave number in the drillstring at the frequency of each component and i is ([minus]1)[sup 1/2]. In another embodiment of this invention, data signals having a frequency content in at least one passband of the drillstring are generated preferably traveling in only one direction (e.g., up the drillstring) while echoes in the drillstring resulting from the data transmission are suppressed. 20 figs.
A method and apparatus for acoustically transmitting data along a drillstring is presented. In accordance with one embodiment of the present invention, acoustic data signals are conditioned to counteract distortions caused by the drillstring. Preferably, this conditioning step comprises multiplying each frequency component of the data signal by exp (-ikL) where L is the transmission length of the drillstring, k is the wave number in the drillstring at the frequency of each component and i is (-1).sup.1/2. In another embodiment of this invention, data signals having a frequency content in at least one passband of the drillstring are generated preferably traveling in only one direction (e.g., up the drillstring) while echoes in the drillstring resulting from the data transmission are suppressed.
Pulse combusted acoustic agglomeration apparatus and process
An improved apparatus and process for removal of particulates entrained in a gas stream are provided. The removal process employs a pulse combustor to provide an acoustic pressure wave to acoustically enhance bimodal agglomeration of particulates which may be collected and removed using a conventional separation apparatus. A particulate having a size different from the size of the particulate in the gas stream to be cleaned is introduced into the system to effectuate the bimodal process. The apparatus may be employed as a direct fired system for improved operation of gas-operated equipment such as a gas turbine, or may, alternatively, be employed as an add-on subsystem for combustion exhaust clean-up. Additionally, the added particulate may be a sorbent for effecting sorption of other contaminants such as sulfur. Various other particulates for contaminant removal may also be introduced into the system as exemplified by alkali-gettering agents.
Mansour, Momtaz N. (Columbia, MD)
An improved apparatus and process for removal of particulates entrained in a gas stream are provided. The removal process employs a pulse combustor to provide an acoustic pressure wave to acoustically enhance agglomeration of particulates which may be collected and removed using a conventional separation apparatus. The apparatus may be employed as a direct fired system for improved operation of gas-operated equipment such as a gas turbine, or may, alternatively, be employed as an add-on subsystem for combustion exhaust clean-up. Additionally, added particulates may include a sorbent for effecting sorption of other contaminants such as sulfur. Various other particulates for contaminant removal may also be introduced into the system as exemplified by alkali-gettering agents.
Mansour, Momtaz N. (Columbia, MD); Chandran, Ravi (Ellicott City, MD)
Methods And Apparatus For Acoustic Fiber Fractionation
Methods and apparatus for acoustic fiber fractionation using a plane ultrasonic wave field interacting with water suspended fibers circulating in a channel flow using acoustic radiation forces to separate fibers into two or more fractions based on fiber radius, with applications of the separation concept in the pulp and paper industry. The continuous process relies on the use of a wall-mounted, rectangular cross-section piezoelectric ceramic transducer to selectively deflect flowing fibers as they penetrate the ultrasonic field. The described embodiment uses a transducer frequency of approximately 150 kHz. Depending upon the amount of dissolved gas in water, separation is obtained using a standing or a traveling wave field.
Brodeur, Pierre (Smyrna, GA)
Development of a geothermal acoustic borehole televiewer
Most geothermal wells are drilled in hard rock formations where fluid flow is through systems of open fractures. Productivity of these wells is usually determined by the extent of intersection of the wellbore with the fracture system. A need exists for fracture mapping methods and tools which can operate in a geothermal environment. In less hostile environments, the acoustic borehole televiewer has been shown to be a useful tool for determining location, orientation, and characterization of fractures as they intersect the borehole and for general wellbore and casing inspection. The development conducted at Sandia National Laboratories to adapt an acoustic borehole televiewer for operation in a geothermal environment is described. The modified instrument has been successfully tested at temperatures as high as 280/sup 0/C and pressures up to 5000 psi, and used successfully to map fractures and casing damage in geothermal wells.
Heard, F.E.; Bauman, T.J.
Argonne Acoustic Levitation Video Goes Viral
"Inside the Advanced Photon Source" Inside the latest Argonne Now "Inside the Advanced Photon Source" Inside the latest Argonne Now APS Director Stephenson Named Argonne Distinguished Fellow Advanced Photon Source, Canadian Light Source Strengthen Ties, Expand X-ray Technology and Research Rose of APS and CNM One of Four DOE Early Career Award Winners Scientists Close-In on Artificial Spider Silk APS News Archives: 2012 | 2011 | 2010 | 2009 2008 | 2007 | 2006 | 2005 2004 | 2003 | 2002 | 2001 2000 Subscribe to APS News rss feed Argonne Acoustic Levitation Video Goes Viral SEPTEMBER 25, 2012 Bookmark and Share Drops of solution being suspended for a long period of time, thanks to the vibrational force of sound waves that keep them stationary in an air column. More than 41,000 Google hits for "acoustic levitation Argonne" as of
Definition: Acoustic Televiewer | Open Energy Information
Televiewer Televiewer Jump to: navigation, search Dictionary.png Acoustic Televiewer The Acoustic Televiewer (ATV) log provides a very-high resolution, sonic image of the borehole wall. The tool consists of an ultrasonic transducer coupled with a downhole inclinometer. These devices are used to generate an oriented image of seismic velocity variation and wave amplitude. These images are then examined and highlighted to reveal fractures, bedding planes and orientation of those features. The log is useful for strata and fracture delineation, and can also be used to evaluate compressional-wave velocity, borehole deviation and eccentricity.[1] References ↑ http://www.dot.ca.gov/hq/esc/geotech/gg/atv_log.htm Ret LikeLike UnlikeLike You like this.Sign Up to see what your friends like.
Acoustic enhancement for photo detecting devices
Provided are improvements to photo detecting devices and methods for enhancing the sensitivity of photo detecting devices. A photo detecting device generates an electronic signal in response to a received light pulse. An electro-mechanical acoustic resonator, electrically coupled to the photo detecting device, damps the electronic signal and increases the signal noise ratio (SNR) of the electronic signal. Increased photo detector standoff distances and sensitivities will result.
Thundat, Thomas G; Senesac, Lawrence R; Van Neste, Charles W
Silent Positioning in Underwater Acoustic Sensor Networks
In this paper, we present a silent positioning scheme termed as UPS for underwater acoustic sensor networks. UPS relies on the time-difference of arrivals measured locally at a sensor to detect range differences from the sensor to four anchor nodes. These range differences are averaged over multiple beacon intervals before they are combined to estimate the 3D sensor location through trilateration. UPS requires no time-synchronization and provides location privacy at underwater vehicles/sensors whose locations need to be determined. To study the performance of UPS, we model the underwater acoustic channel as a modified Ultra Wide Band (UWB) S-V model: the arrival of each path cluster and paths within each cluster follow double Poisson distributions, and the multipath channel gain follows a Rician distribution. Based on this channel model, we perform both theoretical analysis and simulation study on the position error of UPS under acoustic fading channels. The obtained results indicate that UPS is an effective scheme for underwater vehicle/sensor self-positioning.
Xiuzhen Cheng; Haining Shu; Qilian Liang; David Hung-chang Du
Underwater Acoustic Detection of Ultra High Energy Neutrinos
We investigate the acoustic detection method of 10^18-20 eV neutrinos in a Mediterranean Sea environment. The acoustic signal is re-evaluated according to dedicated cascade simulations and a complex phase dependant absorption model, and compared to previous studies. We detail the evolution of the acoustic signal as function of the primary shower characteristics and of the acoustic propagation range. The effective volume of detection for a single hydrophone is given taking into account the limitations due to sea bed and surface boundaries as well as refraction effects. For this 'benchmark detector' we present sensitivity limits to astrophysical neutrino fluxes, from which sensitivity bounds for a larger acoustic detector can be derived. Results suggest that with a limited instrumentation the acoustic method would be more efficient at extreme energies, above 10^20 eV.
V. Niess; V. Bertin
Electret Acoustic Transducer Array For Computerized Ultrasound Risk Evaluation System
An electret-based acoustic transducer array is provided and may be used in a system for examining tissue. The acoustic transducer array is formed with a substrate that has a multiple distinct cells formed therein. Within each of the distinct cells is positioned an acoustic transducing element formed of an electret material. A conductive membrane is formed over the distinct cells and may be flexible.
Moore, Thomas L. (Livermore, CA); Fisher, Karl A. (Brentwood, CA)
The quiet Sun average Doppler shift of coronal lines up to 2 MK
The average Doppler shift shown by spectral lines formed from the chromosphere to the corona reveals important information on the mass and energy balance of the solar atmosphere, providing an important observational constraint to any models of the solar corona. Previous spectroscopic observations of vacuum ultra-violet (VUV) lines have revealed a persistent average wavelength shift of lines formed at temperatures up to 1 MK. At higher temperatures, the behaviour is still essentially unknown. Here we analyse combined SUMER/SoHO and EIS/Hinode observations of the quiet Sun around disk centre to determine, for the first time, the average Doppler shift of several spectral lines formed between 1 and 2 MK, where the largest part of the quiet coronal emission is formed. The measurements are based on a novel technique applied to EIS spectra to measure the difference in Doppler shift between lines formed at different temperatures. Simultaneous wavelength-calibrated SUMER spectra allow establishing the absolute value a...
Dadashi, Neda; Solanki, Sami K
Acoustic ranging technique with application to assessment of low-frequency acoustic noise of wind turbines
Impulsive low-frequency noise from wind turbines can cause annoyance particularly when a residential structure is involved. Such noise is typically generated in some spatially restricted region of a turbine rotor swept area. Low-frequency impulsive noise of the MOD-1 turbine was generated when the rotor blades passed downwind of the tower legs encountering the complex unsteady flows there. An acoustic ranging technique that aids assessment of the degree of concentration of acoustic generation within the turbine swept area and which determines the time-average spatial source region of such concentration is described. Practical applications and limitations of the process are discussed.
Hemphill, R.
fractures are difficult to identify in electrical image logs because of the low percentage of the borehole wall imaged. Analysis of induced structures in acoustic image logs...
Underwater Acoustic Sensor Network with Energy Harvesting Nodes.
??This thesis explores the possibility of a self sustained and service free Underwater Acoustic Sensor Network (UASN). The network nodes are installed along a subsea… (more)
Huseby, Morten
High Frequency Acoustic Wave Scattering From Turbulent Premixed Flames .
??This thesis describes an experimental investigation of high frequency acoustic wave scattering from turbulent premixed flames. The objective of this work was to characterize the… (more)
Narra, Venkateswarlu
MAC and Routing Protocols for Mobile Underwater Acoustic Sensor Swarms
Pressure Routing for Underwater Sensor Networks . . . . . .of Aloha Protocols for Underwater Acoustic Sensor Networks.Critical Applications in Underwater Sensor Networks. In
Noh, Young Tae
Use of an acoustic network as an underwater positioning system .
??Underwater acoustic networks provide an interface between UUVs and surface or land-based control systems. By exploiting range data measured incidental to communications on these networks… (more)
Reed, Michael S.
Using Scanning Acoustic Microscopy to Study Subsurface Defects ...
The resolution of the reflection acoustic microscope is somewhat better than the resolution based on the Rayleigh criterion and is given by the equation6: ...
Nondestructive acoustic electric field probe apparatus and method
The disclosure relates to a nondestructive acoustic electric field probe and its method of use. A source of acoustic pulses of arbitrary but selected shape is placed in an oil bath along with material to be tested across which a voltage is disposed and means for receiving acoustic pulses after they have passed through the material. The received pulses are compared with voltage changes across the material occurring while acoustic pulses pass through it and analysis is made thereof to determine preselected characteristics of the material.
Migliori, Albert (Santa Fe, NM)
WIRELESS MICROWAVE ACOUSTIC SENSOR SYSTEM FOR CONDITION MONITORING IN POWER PLANT ENVIRONMENTS Project DE-FE0007379TDD NETL, Morgantown, WV, March 14, 2012. DOE NETL Program:...
A Real-Time and Offline Quality Control Methodology for SeaSonde High-Frequency Radar Currents
A near-real-time and offline quality control methodology for SeaSonde systems is proposed. It is applied on radial current maps and is based on the determination of the signal-to-noise ratio (SNR) values of the Doppler lines that contribute to the ...
Simone Cosoli; Giorgio Bolzon; Andrea Mazzoldi
Using 3DF GPS Heading for Improving Underway ADCP Data
Systematic error in the cross-track velocity measured under way from shipboard acoustic Doppler current profilers (ADCPs) can be attributed to error in measuring the ship's heading with a gyrocompass. Drift- and direction-dependent errors in ...
Gwyn Griffiths
Restratification of the Surface Mixed Layer with Submesoscale Lateral Density Gradients: Diagnosing the Importance of the Horizontal Dimension
A depth-cycling towed conductivity–temperature–depth (CTD) and vessel-mounted acoustic Doppler current profiler (ADCP) were used to obtain four-dimensional measurements of the restratification of the surface mixed layer (SML) at a submesoscale ...
P. J. Hosegood; M. C. Gregg; M. H. Alford
Using a Broadband ADCP in a Tidal Channel. Part I: Mean Flow and Shear
This paper discusses the principles of measuring the mean velocity and its vertical shear in a turbulent flow using an acoustic Doppler current profiler (ADCP), and presents an analysis of data gathered in a tidal channel. The assumption of ...
Youyu Lu; Rolf G. Lueck
Hydraulic Interpretation of Direct Velocity Measurements in the Bab al Mandab
Acoustic Doppler Current Profiler velocity measurements in the Bab al Mandab during the period June 1995–March 1996 are used to assess the hydraulic character of the exchange flow. The strait is 150 km long and contains two distinct geometrical ...
L. J. Pratt; William Johns; Stephen P. Murray; Katsurou Katsumata
--No Title--
Energy.gov (U.S. Department of Energy (DOE)) Indexed Site
The use of Compact Mixer Pumps to clean waste tanks will be tested at the 85' diameter tank at TNX. A StreamPro ADCP (Acoustic Doppler Current Profiler) has been ordered to measure...
Comparison of Reynolds Stress Estimates Derived from Standard and Fast-Ping ADCPs
A field experiment was conducted to directly compare the effects of different sampling modes on Reynolds stress estimates calculated from acoustic Doppler current profilers (ADCPs). Two 1.2-MHz ADCPs were deployed concurrently over a fortnightly ...
Nicholas J. Nidzieko; Derek A. Fong; James L. Hench
Evaluation of the Accuracy of a Ship-Mounted, Bottom-Tracking ADCP in a Near-Shore Coastal Flow
The accuracy of an acoustic Doppler current profiler (ADCP) used with an internal bottom-tracking system is considered. The boat speed measured using bottom tracking is extremely accurate, comparable to the speeds measured by a high-resolution, ...
Derek A. Fong; Stephen G. Monismith
Spatial Variability of Diapycnal Mixing and Turbulent Dissipation Rates in a Stagnant Fjord Basin
Two microstructure profilers, two ships, and four moorings with acoustic Doppler current profilers and conductivity–temperature loggers were used in an intensive effort to map the spatial and temporal variations of vertical mixing in the stagnant ...
Lars Arneborg; Carol Janzen; Bengt Liljebladh; Tom P. Rippeth; John H. Simpson; Anders Stigebrandt
Intercomparison of ADCP Measurements at 0°, 140°W
Three sets of horizontal velocity measurements obtained within 3 miles of each other at 0°, 140°W are compared. Measurements were taken by acoustic Doppler current Profilers (ADCPs) on different platforms, with different tracking filter ...
Ren-Chieh Lien; Michael J. McPhaden; Dave Rebert
Eddy Energetics in the Upper Equatorial Pacific during the Hawaii-to-Tahiti Shuttle Experiment
Eddy energetics in the central equatorial Pacific Ocean is examined using Acoustic Doppler Current Profiler velocities and CTD densities collected during the Hawaii-to-Tahiti Shuttle Experiment, in 1979–80. Three distinct sources of eddy energy ...
Douglas S. Luther; Eric S. Johnson
A Composite View of Surface Signatures and Interior Properties of Nonlinear Internal Waves: Observations and Applications
Surface signatures and interior properties of large-amplitude nonlinear internal waves (NLIWs) in the South China Sea (SCS) were measured during a period of weak northeast wind (2 m s?1) using shipboard marine radar, an acoustic Doppler current ...
Ming-Huei Chang; Ren-Chieh Lien; Yiing Jang Yang; Tswen Yung Tang; Joe Wang
Observations of Deep Convection in the Gulf of Lions, Northern Mediterranean, during the Winter of 1991/92
During December 1991 to April 1992 measurements with moored acoustic Doppler current profiler (ADCP) stations and shipboard surveys were carried out in the convection regime of the Gulf of Lions, northwestern Mediterranean. First significant ...
Friedrich Schott; Martin Visbeck; Uwe Send; Jürgen Fischer; Lothar Stramma; Yves Desaubies
Wind-Driven Ageostrophic Transport in the North Equatorial Countercurrent of the Eastern Pacific at 95°W
Observations of horizontal velocity from two shipboard acoustic Doppler current profilers (ADCPs), as well as wind, temperature, and salinity observations from a cruise during June–July 2001, are used to compute a simplified mean meridional ...
Janet Sprintall; Sean Kennan; Yoo Yin Kim; Peter Niiler
Cold Outflow from the Faroe Bank Channel
The exchange of water between the Norwegian Sea and the North Atlantic around the Faroe Islands was investigated in 1987 and 1988 combining CTD data with shipborne Acoustic Doppler Current Profiler (ADCP)measurements. Tests were devised to assess ...
P. M. Saunders
The Finescale Response of Lowered ADCP Velocity Measurements Processed with Different Methods
In a paper published in 2002 in this journal, K. Polzin et al. derive corrections for spectra of vertical shear calculated from lowered acoustic Doppler current profiler (LADCP) velocity data. To illustrate and validate the corrections, they use ...
A. M. Thurnherr
Velocity Structure of Internal Tide Beams Emanating from Kaena Ridge, Hawaii
Observations are reported of the semidiurnal (M2) internal tide across Kaena Ridge, Hawaii. Horizontal velocity in the upper 1000–1500 m was measured during eleven ~240-km-long shipboard acoustic Doppler current profiler (ADCP) transects across ...
Andy Pickering; Matthew H. Alford
Autonomous Underwater Vehicle Measurements of Surface Wave Decay and Directional Spectra in the Marginal Sea Ice Zone
In March 2003 several autonomous underwater vehicle (AUV) missions were carried out under sea ice in the western Bellingshausen Sea. Data from the upward-looking acoustic Doppler current profiler (ADCP) on the "Autosub" AUV indicate a strongly ...
Daniel R. Hayes; Adrian Jenkins; Stephen McPhail
Estimating Lagrangian Trajectories with an ADCP
Lagrangian trajectories may be estimated with an Acoustic Doppler Current Profiler (ADCP) as an alternative to tracking parcels with floats. By using the depth of isopycnals from a conductivity–temperature–depth (CTD) instrument and the ...
J. Rajamony; D. Hebert; T. Rossby
A study of the location of the entrance of a fishway in a regulated river with CFD and ADCP
Simulation-driven design with computational fluid dynamics has been used to evaluate the flow downstream of a hydropower plant with regards to upstream migrating fish. Fieldmeasurements with an Acoustic Doppler Current Profiler were performed, and the ...
Anders G. Andersson; Dan-Erik Lindberg; Elianne M. Lindmark; Kjell Leonardsson; Patrik Andreasson; Hans Lundqvist; T. Staffan Lundström
Calculating Reynolds Stresses from ADCP Measurements in the Presence of Surface Gravity Waves Using the Cospectra-Fit Method
Recently, the velocity observations of acoustic Doppler current profilers (ADCPs) have been successfully used to estimate turbulent Reynolds stresses in estuaries and tidal channels. However, the presence of surface gravity waves can ...
Anthony R. Kirincich; Steven J. Lentz; Gregory P. Gerbi
Field Verification of ADCP Surface Gravity Wave Elevation Spectra
Acoustic Doppler current profilers (ADCPs) can measure orbital velocities induced by surface gravity waves, yet the ADCP estimates of these velocities are subject to a relatively high noise level. The present paper introduces a linear filtration ...
A. J. F. Hoitink; H. C. Peters; M. Schroevers
A Proposal of Pulse-Pair Doppler Operation on a Spaceborne Cloud-Profiling Radar in the W Band
Pulse-pair Doppler operation is considered for the spaceborne mission. In a formalism, the condition that a measured Doppler velocity on pulse-pair operation corresponds to that on the FFT operation is derived. The coherent coupling effect of the ...
Satoru Kobayashi; Hiroshi Kumagai; Hiroshi Kuroiwa
Analyzing neural correlates of attentional changes during the exposure to virtual environments: application of transcranial doppler monitoring
Transcranial Doppler monitoring (TCD) has been proposed as a tool to be used in Augmented Cognition (AugCog) systems to monitor brain activation during the performance of different cognitive tasks. In the present study, the main goal is to analyze variations ... Keywords: augmented cognition, cognitive state assessment, neurophysiological data, transcranial doppler, virtual reality
Beatriz Rey; Vera Parkhutik; José Tembl; Mariano Alcańiz
Doppler Radar Signatures of Developing Thunderstorms and Their Potential to Indicate the Onset of Cloud-to-Ground Lightning
The capability of Doppler weather radars to short-term forecast the initiation of thunderstorms and the onset of cloud-to-ground (CG) lightning is examined. Doppler weather radar data from 28 thunderstorms were analyzed from August 1990 in the ...
Kurt D. Hondl; Michael D. Eilts
Tropical Cyclone Kinematic Structure Retrieved from Single-Doppler Radar Observations. Part II: The GBVTD-Simplex Center Finding Algorithm
This paper is the second of a series and focuses on developing an algorithm to objectively identify tropical cyclone (TC) vorticity centers using single-Doppler radar data. The first paper dealt with the formulation of a single-Doppler radar TC ...
Wen-Chau Lee; Frank D. Marks Jr.
Polarimetric and Dual-Doppler Radar Observations of the Lipscomb County, Texas, Supercell Thunderstorm on 23 May 2002
Polarimetric and dual-Doppler observations of a supercell observed by the National Center for Atmospheric Research (NCAR) S-band Polarimetric (SPOL) radar, two Doppler-On-Wheels (DOW) radars, and the Greek XPOL radar on 23 May 2002 during the ...
Jeffrey Frame; Paul Markowski; Yvette Richardson; Jerry Straka; Joshua Wurman
EnKF Assimilation of High-Resolution, Mobile Doppler Radar Data of the 4 May 2007 Greensburg, Kansas, Supercell into a Numerical Cloud Model
Mobile Doppler radar data, along with observations from a nearby Weather Surveillance Radar-1988 Doppler (WSR-88D), are assimilated with an ensemble Kalman filter (EnKF) technique into a nonhydrostatic, compressible numerical weather prediction ...
Robin L. Tanamachi; Louis J. Wicker; David C. Dowell; Howard B. Bluestein; Daniel T. Dawson II; Ming Xue
Three-Dimensional Air Circulation in a Squall Line from Airborne Dual-Beam Doppler Radar Data: A Test of Coplane Methodology Software
The detailed structure of a tropical squall line observed in central Florida was investigated from an airborne dual-beam Doppler radar, pointing respectively fore and aft. This allowed dual-Doppler observations from a straight flight path in a ...
Michel Chong; Jacques Testud
Self-adaptive methods for acoustic focusing and mode extraction in a shallow ocean waveguide
1.1 Time-reversal in the shallow ocean . . . . . .applications versus ocean acoustic SONAR and communicationsH. Schmidt, Computational Ocean Acoustics, (AIP New York,
Walker, Shane C.
Spectrally efficient underwater acoustic communications : channel characterization and design aspects for OFDM
with L = 9 for an underwater channel impulse response with Ladaptive modulation in underwater acoustic communications,"Adaptive OFDM for underwater acoustic channels with limited
Radoševi?, Andreja
Quantitative Analysis and Interpretation of Dot Echoes Observed with a Doppler Sodar
While some people involved in the acoustic remote sensing field are aware of the possibility of receiving dot echoes from nonatmospheric targets, most of the papers available in the scientific literature dealing with this phenomenon associate ...
G. Mastrantonio; J. Naithani; P. S. Anderson; S. Argentini; I. Petenko
Acoustic analogues of black hole singularities
We search for acoustic analogues of a spherical symmetric black hole with a pointlike source. We show that the gravitational system has a dynamical counterpart in the constrained, steady motion of a fluid with a planar source. The equations governing the dynamics of the gravitational system can be exactly mapped in those governing the motion of the fluid. The different meaning that singularities and sources have in fluid dynamics and in general relativity is also discussed. Whereas in the latter a pointlike source is always associated with a (curvature) singularity in the former the presence of sources does not necessarily imply divergences of the fields.
Cadoni, Mariano; Mignemi, Salvatore [Dipartimento di Fisica, Universita di Cagliari, and INFN, Sezione di Cagliari, Cittadella Universitaria 09042 Monserrato (Italy); Dipartimento di Matematica, Universita di Cagliari, viale Merello 92, 09123 Cagliari, Italy, and INFN, Sezione di Cagliari (Italy)
Mariano Cadoni; Salvatore Mignemi
Underwater Acoustic Sensor Networks: Research Challenges
Underwater sensor nodes will find applications in oceanographic data collection, pollution monitoring, o#shore exploration, disaster prevention, assisted navigation and tactical surveillance applications. Moreover, unmanned or autonomous underwater vehicles (UUVs, AUVs), equipped with sensors, will enable the exploration of natural undersea resources and gathering of scientific data in collaborative monitoring missions. Underwater acoustic networking is the enabling technology for these applications. Underwater networks consist of a variable number of sensors and vehicles that are deployed to perform collaborative monitoring tasks over a given area.
Ian Akyildiz Dario; Ian F. Akyildiz; Dario Pompili; Tommaso Melodia
Underwater sensor nodes will find applications in oceanographic data collection, pollution monitoring, o#shore exploration, disaster prevention, assisted navigation and tactical surveillance applications. Moreover, unmanned or autonomous underwater vehicles (UUVs, AUVs), equipped with sensors, will enable the exploration of natural undersea resources and gathering of scientific data in collaborative monitoring missions. Underwater acoustic networking is the enabling technology for these applications. Underwater networks consist of a variable number of sensors and vehicles that are deployed to perform collaborative monitoring tasks over a given area. In this
Ian F. Akyildiz; Dario Pompili; Tommaso Melodia
Energy flow in acoustic black holes
We present the results of an analysis of superradiant energy flow due to scalar fields incident on an acoustic black hole. In addition to providing independent confirmation of the recent results in [E. Berti, V. Cardoso, and J. P. S. Lemos, Phys. Rev. D 70, 124006 (2004).], we determine in detail the profile of energy flow everywhere outside the horizon. We confirm explicitly that in a suitable frame the energy flow is inward at the horizon and outward at infinity, as expected on physical grounds.
Choy, K.; Kruk, T.; Carrington, M.E.; Fugleberg, T.; Zahn, J.; Kobes, R.; Kunstatter, G.; Pickering, D. [Department of Physics, Brandon University, Brandon, Manitoba, R7A 6A9 (Canada) and Winnipeg Institute for Theoretical Physics, Winnipeg, Manitoba (Canada); Department of Physics, University of Winnipeg, Winnipeg, Manitoba, R7A 6A9 (Canada) and Winnipeg Institute for Theoretical Physics, Winnipeg, Manitoba (Canada); Department of Mathematics, Brandon University, Brandon, Manitoba, R7A 6A9 (Canada)
Tomographic Maps of the Ocean Mesoscale. Part 1: Pure Acoustics
A field test of ocean acoustic tomography was conducted in 1981 for a two month period in a 300 km square at 26°N, 70°W in the North Atlantic (just south of the MODE region). Nine acoustic deep-sea moorings with sea floor transponders for ...
B. Cornuelle; C. Wunsch; D. Behringer; T. Birdsall; M. Brown; R. Heinmiller; R. Knox; K. Metzger; W. Munk; J. Spiesberger; R. Spindel; D. Webb; P. Worcester
Focused beam routing protocol for underwater acoustic networks
Multi-hop transmission is considered for large coverage areas in bandwidth-limited underwater acoustic networks. In this paper, we present a scalable routing technique based on location information, and optimized for minimum energy per bit consumption. ... Keywords: power control, routing, underwater acoustic networks
Josep Miquel Jornet; Milica Stojanovic; Michele Zorzi
Acoustic detection of partial discharges in insulation oil
In this paper, we performed an insulation diagnosis technique for oil-immersed power transformers by an acoustic detection method. Electrode system such as needle to plane electrode was fabricated to simulate a defect of power transformers. In addition, ... Keywords: acoustic detection, frequency component, insulation diagnostic, partial discharge, positioning
Dae-Won Park; Sang-Wook Cha; Gyung-Suk Kil
Intelligent acoustic rotor speed estimation for an autonomous helicopter
Acoustic sensing to gather information about a machine can be highly beneficial, but processing the data can be difficult. In this work, a variety of methodologies have been studied to extract rotor speed information from the sound signature of an autonomous ... Keywords: Acoustic sensing, Adaptive network-based fuzzy inference system, Artificial neural network, Feature selection, Genetic algorithm, Helicopter, Rotor speeds
Benjamin N. Passow; Mario A. Gongora; Adrian A. Hopgood; Sophy Smith
Fast LMS/Newton algorithms for stereophonic acoustic echo cancelation
This paper presents a new class of adaptive filtering algorithms to solve the stereophonic acoustic echo cancelation (AEC) problem in teleconferencing systems. While stereophonic AEC may be seen as a simple generalization of the well-known single-channel ... Keywords: LMS/Newton, adaptive filters, lattice orthogonalization, stereo acoustic echo cancellation (AEC)
Harsha I. K. Rao; Behrouz Farhang-Boroujeny
Resonant acoustic transducer system for a well drilling string
For use in transmitting acoustic waves propated along a well drilling string, a piezoelectric transducer is provided operating in the relatively low loss acoustic propagation range of the well drilling string. The efficiently coupled transmitting transducer incorporates a mass-spring-piezoelectric transmitter combination permitting a resonant operation in the desired low frequency range.
Nardi, Anthony P. (Burlington, MA)
For use in transmitting acoustic waves propagated along a well drilling string, a piezoelectric transducer is provided operating in the relatively low loss acoustic propagation range of the well drilling string. The efficiently coupled transmitting transducer incorporates a mass-spring-piezoelectric transmitter combination permitting resonant operation in the desired low frequency range.
Kent, William H. (Westford, MA); Mitchell, Peter G. (Concord, MA)
Single- and Dual-Doppler Analysis of a Tornadic Vortex and Surrounding Storm-Scale Flow in the Crowell, Texas, Supercell of 30 April 2000
Fine-resolution single- and dual-Doppler data were collected in the tornadic region of a supercell storm intercepted by two Doppler-on-Wheels radars on 30 April 2000 near Crowell, Texas. Eleven dual-Doppler analyses characterize the 2D and 3D ...
James Marquis; Yvette Richardson; Joshua Wurman; Paul Markowski
Acoustically enhanced remediation of contaminated soils and ground water. Volume 1
The Phase 1 laboratory bench-scale investigation results have shown that acoustically enhanced remediation (AER) technology can significantly accelerate the ground water remediation of non-aqueous phase liquids (NAPLs) in unconsolidated soils. The testing also determined some of the acoustic parameters which maximize fluid and contaminant extraction rates. A technology merit and trade analysis identified the conditions under which AER could be successfully deployed in the field, and an analysis of existing acoustical sources and varying methods for their deployment found that AER technology can be successfully deployed in-situ. Current estimates of deployability indicate that a NAPL plume 150 ft in diameter can be readily remediated. This program focused on unconsolidated soils because of the large number of remediation sites located in this type of hydrogeologic setting throughout the nation. It also focused on NAPLs and low permeability soil because of the inherent difficult in the remediation of NAPLs and the significant time and cost impact caused by contaminated low permeability soils. This overall program is recommended for Phase 2 which will address the technology scaling requirements for a field scale test.
Wind Profiling by Doppler Weather Radar Iwan Holleman (email@example.com)
Wind Profiling by Doppler Weather Radar Iwan Holleman (email@example.com) Royal Netherlands wind profiles at a high temporal resolution. Several algorithms and quality ensuring procedures for the extraction of wind profiles from radar volume data have been published. A comparison and verification
Stoffelen, Ad
Scatter and Doppler Effect of Wind Power Plants to Land Radars
Wind power plant installations at different scales are in an increasing pattern starting from year 2000. A curiosity has been raised about 4-5 years ago for if wind turbines interfere with radars. The interference occurs when wind turbines reflect radar ... Keywords: clutter, Doppler, radar, scatter, turbine, wind
Derya Sozen; Mesut Kartal
Single-Doppler Velocity Retrieval with Rapid-Scan Radar Data
An approximate (rapid scan) dynamical model for single-Doppler retrieval of the vector wind field is investigated. This approximate model is based on the Lagrangian form of the radial component of the equation of motion and is valid for retrieval ...
Alan Shapiro; Paul Robinson; Joshua Wurman; Jidong Gao
Errors in Wind Measurements Estimated by Five-Beam Phased Array Doppler Sodar
Estimation of the errors in sodar wind measurements using the phased array Doppler sodar operated under five-beam observation has been made. When compared with the sonic anemometer on the tower nearby, the variances or second-order moments of ...
Yoshiki Ito
Velocity Biases of Adaptive Filter Estimates in Heterodyne Doppler Lidar Measurements
Frequency estimates by heterodyne Doppler lidar (HDL) may result in velocity bias due to the atmospheric speckle effect and an asymmetrical power spectrum of the probing pulse, as discussed in a previous paper by Dabas et al. In this paper, it ...
Estimation and Mapping of Hurricane Turbulent Energy Using Airborne Doppler Measurements
Hurricane turbulent kinetic energy (TKE) was computed using airborne Doppler measurements from the NOAA WP-3D tail radars, and TKE data were retrieved for a variety of storms at different stages of their life cycle. The geometry of the radar ...
Sylvie Lorsolo; Jun A. Zhang; Frank Marks Jr.; John Gamache
Doppler Radar Observations of the Development of a Boundary-Layer Nocturnal Jet
A single Doppler radar obtained detailed clear-air measurements of the development of a strong boundary-layer nocturnal jet in North Dakota during the summer of 1989. The evolution of the jet was monitored by the radar with a high degree of ...
A. Shelby Frisch; Brad W. Orr; Brooks E. Martner
Real–Time Wind Synthesis from Doppler Radar Observations during the Mesoscale Alpine Programme
A real–time and automated multiple–Doppler analysis method for ground–based radar data, with an emphasis on observations conducted over complex terrain, is presented. It is the result of a joint effort of the radar groups of Centre National de ...
M. Chong; J-F. Georgis; O. Bousquet; S. R. Brodzik; C. Burghart; S. Cosma; U. Germann; V. Gouget; R. A. Houze Jr.; C. N. James; S. Prieur; R. Rotunno; F. Roux; J. Vivekanandan; Z-X. Zeng
Evolution of the Monterey Bay Sea-Breeze Layer As Observed by Pulsed Doppler Lidar
As part of the Land/Sea Breeze Experiment (LASBEX) to study the sea breeze at Monterey Bay, the pulsed Doppler lidar of the NOAA/ERL Wave Propagation Laboratory performed vertical and nearly horizontal scans of the developing sea breeze on 12 ...
Robert M. Banta; Lisa D. Olivier; David H. Levinson
Measurement of Ocean Wave Directional Spectra Using Doppler Side-Scan Sonar Arrays
A technique is presented for extraction of ocean wave directional spectra using Doppler side-scan sonars. Two 103-kHz steerable side-scan beams from a freely drifting subsurface platform are used to estimate horizontal water surface velocity due ...
Mark V. Trevorrow
Unusually Long Duration, Multiple-Doppler Radar Observations of a Front in a Convective Boundary Layer
Dual-Doppler observations acquired by a network of mobile radars deployed in the Oklahoma panhandle on 3 June 2002 are used to document the kinematic structure and evolution of a front. The data were collected during the International H2O Project ...
John R. Stonitsch; Paul M. Markowski
Doppler-Radar Analysis of a Low-Precipitation Severe Storm
This is a detailed study of the structure and evolution of a convective storm that formed along the dryline in Oklahoma on 26 April 1984 and developed into a supercell. Dual-Doppler wind analyses, analyses of surface-mesonetwork and instrumented-...
Howard B. Bluestein; Gary R. Woodall
An Analysis of the Performance of the UFAM Pulsed Doppler Lidar for Observing the Boundary Layer
The performance of the 1.5-?m pulsed Doppler lidar, operated by the U.K. Universities Facility for Atmospheric Measurement (UFAM) over a 51-day continuous and unattended field deployment in southern England, is described and analyzed with a view ...
Guy Pearson; Fay Davies; Chris Collier
Experimental Validation of Wind Profiling Performed by the Airborne 10-?m Heterodyne Doppler Lidar WIND
The airborne Wind Infrared Doppler Lidar (WIND) has been developed through French–German cooperation. The system is based on a pulsed 10.6-?m laser transmitter, a heterodyne receiver, and a conical scanning device. To the authors' knowledge, it ...
Oliver Reitebuch; Christian Werner; Ines Leike; Patricia Delville; Pierre H. Flamant; Alexander Cress; Dirk Engelbart
Mobile, Phased-Array, Doppler Radar Observations of Tornadoes at X Band
A mobile, phased-array Doppler radar, the Mobile Weather Radar, 2005 X-band, Phased Array (MWR-05XP), has been used since 2007 to obtain data in supercells and tornadoes. Rapidly-updating, volumetric data of tornadic vortex signatures (TVSs) ...
Michael M. French; Howard B. Bluestein; Ivan PopStefanija; Chad A. Baldi; Robert T. Bluth
Doppler Sonar Observations of Internal Waves: The Wavenumber-Frequency Spectrum
In May 1980 an 18-day sequence of velocity profiles of the top 600 m of the sea was collected off the coast of Southern California. The measurements were obtained using a pair of Doppler sonars mounted on the Research Platform FLIP. From these ...
R. Pinkel
Estimating the Most Steady Frame of Reference from Doppler Radar Data
A method is described to determine the most steady frame of reference of a weather system from data from one or more Doppler radars at three analysis times. The most steady frame of reference is that frame in which the velocity field displays the ...
Thomas Matejka
Statistical Analysis of Sodium Doppler Wind–Temperature Lidar Measurements of Vertical Heat Flux
A statistical study is presented of the errors in sodium Doppler lidar measurements of wind and temperature in the mesosphere that arise from the statistics of the photon-counting process that is inherent in the technique. The authors use data ...
Liguo Su; Richard L. Collins; David A. Krueger; Chiao-Yao She
Quality Control Algorithms for the Kennedy Space Center 50-MHz Doppler Radar Wind Profiler Winds Database
This paper presents the process used by the Marshall Space Flight Center Natural Environments Branch (EV44) to quality control (QC) data from the Kennedy Space Center's 50-MHz Doppler radar wind profiler (DRWP) for use in vehicle wind loads and ...
Robert E. Barbré Jr.
Performance of a 2-µm Coherent Doppler Lidar for Wind Measurements
Measurements of boundary layer winds are presented using a 2-µm coherent Doppler lidar and the optimal performance of the maximum likelihood estimator. The systematic error for single-shot estimates was estimated as 3.6 cm s?1 using measurements ...
Rod Frehlich; Stephen M. Hannon; Sammy W. Henderson
Four-dimensional variational data assimilation for Doppler radar wind data
All forecast models, whether they represent the state of the weather, the spread of a disease, or levels of economic activity, contain unknown parameters. These parameters may be the model's initial conditions, its boundary conditions, or other tunable ... Keywords: 3D-Var, 4D-Var, Adjoint, Data assimilation, Doppler radar, NWP, Nonlinear bias, Sensitivity
Fathalla A. Rihan; Chris G. Collier; Ian Roulstone
Wind-Flow Patterns in the Grand Canyon as Revealed by Doppler Lidar
Many interesting flow patterns were found in the Grand Canyon by a scanning Doppler lidar deployed to the south rim during the 1990 Wintertime Visibility Study. Three are analyzed in this study: 1) flow reversal in the canyon, where the flow in ...
Robert M. Banta; Lisa S. Darby; Pirmin Kaufmann; David H. Levinson; Cui-Juan Zhu
Analysis of Airborne Doppler Lidar Measurements of the Extended California Sea Breeze
The analysis of airborne Doppler lidar data taken by NASA near the top of the planetary boundary layer in the central valley of California is presented. These data include downward wan angles that intercept the ground. The maximum errors in the ...
John J. Carroll
An Integrating Velocity–Azimuth Process Single-Doppler Radar Wind Retrieval Method
Among the single-Doppler radar wind analysis methods, the velocity–azimuth display (VAD), velocity–azimuth process (VAP), and uniform-wind (UW) methods are widely used because of their simplicity. This paper shows that the VAD, VAP, and UW ...
Xudong Liang