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Sample records for acoustic current meter

  1. Mesoscale current fields observed with a shipboard profiling acoustic current meter

    SciTech Connect

    Regier, L.

    1982-08-01

    Measurements of the near-surface currents obtained with a shipboard acoustic current meter during the POLYMODE Local Dynamics Experiment are discussed. The large-scale spatial structure of the directly measured currents is very similar to that obtained from simultaneous hydrographic observations assuming geostrophic dynamics. The vertical shear of geostrophic currents is half that observed directly, and the two are poorly correlated. Vertical shear is dominated by currents having spatial scales shorter than about 180 km and having no geostrophic signature. Although the shear of the ageostrophic component is clearly evident, estimation of the ageostrophic current is hampered by large experimental uncertainties.

  2. Laboratory evaluation of an OTT acoustic digital current meter and a SonTek Laboratory acoustic Doppler velocimeter

    USGS Publications Warehouse

    Vermeyen, T.B.; Oberg, Kevin A.; Jackson, Patrick Ryan

    2009-01-01

    Recently, an acoustic current meter known as the OTT * acoustic digital current meter (ADC) was introduced as an alternative instrument for stream gaging measurements. The Bureau of Reclamation and the U.S. Geological Survey collaborated on a side- by-side evaluation of the ADC and a SonTek/YSI acoustic Doppler velocimeter (ADV). Measurements were carried out in a laboratory flume to evaluate the performance characteristics of the ADC under a range of flow and boundary conditions. The flume contained a physical model of a mountain river with a diversion dam and variety of bed materials ranging from smooth mortar to a cobble bed. The instruments were installed on a trolley system that allowed them to be easily moved within the flume while maintaining a consistent probe orientation. More than 50 comparison measurements were made in an effort to verify the manufacturer’s performance specifications and to evaluate potential boundary disturbance for near-bed and vertical boundary measurements. Data and results from this evaluation are presented and discussed. 

  3. Acoustic velocity meter systems

    USGS Publications Warehouse

    Laenen, Antonius

    1985-01-01

    Acoustic velocity meter (AVM) systems operate on the principles that the point-to-point upstream traveltime of an acoustic pulse is longer than the downstream traveltime and that this difference in traveltime can be accurately measured by electronic devices. An AVM system is capable of recording water velocity (and discharge) under a wide range of conditions, but some constraints apply: 1. Accuracy is reduced and performance is degraded if the acoustic path is not a continuous straight line. The path can be bent by reflection if it is too close to a stream boundary or by refraction if it passes through density gradients resulting from variations in either water temperature or salinity. For paths of less than 100 m, a temperature gradient of 0.1' per meter causes signal bending less than 0.6 meter at midchannel, and satisfactory velocity results can be obtained. Reflection from stream boundaries can cause signal cancellation if boundaries are too close to signal path. 2. Signal strength is attenuated by particles or bubbles that absorb, spread, or scatter sound. The concentration of particles or bubbles that can be tolerated is a function of the path length and frequency of the acoustic signal. 3. Changes in streamline orientation can affect system accuracy if the variability is random. 4. Errors relating to signal resolution are much larger for a single threshold detection scheme than for multiple threshold schemes. This report provides methods for computing the effect of various conditions on the accuracy of a record obtained from an AVM. The equipment must be adapted to the site. Field reconnaissance and preinstallation analysis to detect possible problems are critical for proper installation and operation of an AVM system.

  4. Improving H-Q rating curves in temprorary streams by using Acoustic Doppler Current meters

    NASA Astrophysics Data System (ADS)

    Marchand, P.; Salles, C.; Rodier, C.; Hernandez, F.; Gayrard, E.; Tournoud, M.-G.

    2012-04-01

    Intermittent rivers pose different challenges to stream rating due to high spatial and temporal gradients. Long dry periods, cut by short duration flush flood events explain the difficulty to obtain reliable discharge data, for low flows as well as for floods: problems occur with standard gauging, zero flow period, etc. Our study aims to test the use of an acoustic Doppler currentmeter (ADC) for improving stream rating curves in small catchments subject to large variations of discharge, solid transport and high eutrophication levels. The study is conducted at the outlet of the river Vène, a small coastal river (67 km2) located close to the city of Montpellier (France). The low flow period lasts for more than 6 month; during this period the river flow is sustained by effluents from urban sewage systems, which allows development of algae and macrophytes in the riverbed. The ADC device (Sontek ®Argonaut SW) is a pulsed Doppler current profiling system designed for measuring water velocity profiles and levels that are used to compute volumetric flow rates. It is designed for shallow waters (less than 4 meter depth). Its main advantages are its low cost and high accuracy (±1% of the measured velocity or ±0.05 m/sec, as reported by the manufacturer). The study will evaluate the improvement in rating curves in an intermittent flow context and the effect of differences in sensitivity between low and high water level, by comparing mean flow velocity obtained by ADC to direct discharges measurements. The study will also report long-term use of ADC device, by considering effects of biofilms, algae and macrophytes, as well as solid transport on the accuracy of the measurements. In conclusion, we show the possibility to improve stream rating and continuous data collection of an intermittent river by using a ADC with some precautions.

  5. Comparison of acoustic doppler current profiler and Price AA mechanical current meter measurements made during the 2011 Mississippi River Flood

    USGS Publications Warehouse

    O'Brien, Patrick; Mueller, David; Pratt, Thad

    2012-01-01

    The Mississippi River and Tributaries project performed as designed during the historic 2011 Mississippi River flood, with many of the operational decisions based on discharge targets as opposed to stage. Measurement of discharge at the Tarbert Landing, Mississippi range provides critical information used in operational decisions for the floodways located in Louisiana. Historically, discharge measurements have been made using a Price AA current meter and the mid-section method, and a long record exists based on these types of measurements, including historical peak discharges. Discharge measurements made using an acoustic Doppler current profiler from a moving boat have been incorporated into the record since the mid 1990's, and are used along with the Price AA mid-section measurements. During the 2011 flood event, both methods were used and appeared to provide different results at times. The apparent differences between the measurement techniques are due to complex hydrodynamics at this location that created large spatial and temporal fluctuations in the flow. The data and analysis presented herein show the difference between the two methods to be within the expected accuracy of the measurements when the measurements are made concurrently. The observed fluctuations prevent valid comparisons of data collected sequentially or even with different observation durations.

  6. Acoustic ground impedance meter

    NASA Technical Reports Server (NTRS)

    Zuckerwar, A. J.

    1981-01-01

    A compact, portable instrument was developed to measure the acoustic impedance of the ground, or other surfaces, by direct pressure-volume velocity measurement. A Helmholz resonator, constructed of heavy-walled stainless steel but open at the bottom, is positioned over the surface having the unknown impedance. The sound source, a cam-driven piston of known stroke and thus known volume velocity, is located in the neck of the resonator. The cam speed is a variable up to a maximum 3600 rpm. The sound pressure at the test surface is measured by means of a microphone flush-mounted in the wall of the chamber. An optical monitor of the piston displacement permits measurement of the phase angle between the volume velocity and the sound pressure, from which the real and imaginary parts of the impedance can be evaluated. Measurements using a 5-lobed cam can be made up to 300 Hz. Detailed design criteria and results on a soil sample are presented.

  7. Measurement of velocities with an acoustic velocity meter, one side-looking and two upward-looking acoustic Doppler current profilers in the Chicago Sanitary and Ship Canal, Romeoville, Illinois

    USGS Publications Warehouse

    Oberg, Kevin A.; Duncker, James J.

    1999-01-01

    In 1998, a prototype 300 kHz, side-looking Acoustic Doppler Current Profiler (ADCP) was deployed in the Chicago Sanitary and Ship Canal (CSSC) at Romeoville, Illinois. Additionally, two upward-looking ADCP's were deployed in the same acoustic path as the side-looking ADCP and in the reach defined by the upstream and downstream acoustic velocity meter (AVM) paths. All three ADCP's were synchronized to the AVM clock at the gaging station so that data were sampled simultaneously. The three ADCP's were deployed for six weeks measuring flow velocities from 0.0 to 2.5 ft/s. Velocities measured by each ADCP were compared to AVM path velocities and to velocities measured by the other ADCP's.

  8. Solid state recording current meter conversion

    USGS Publications Warehouse

    Cheng, Ralph T.; Wang, Lichen

    1985-01-01

    The authors describe the conversion of an Endeco-174 current meter to a solid-state recording current meter. A removable solid-state module was designed to fit in the space originally occupied by an 8-track tape cartridge. The module contains a CPU and 128 kilobytes of nonvolatile CMOS memory. The solid-state module communicates with any terminal or computer using an RS-232C interface at 4800 baud rate. A primary consideration for conversion was to keep modifications of the current meter to a minimum. The communication protocol was designed to emulate the Endeco tape translation unit, thus the need for a translation unit was eliminated and the original data reduction programs can be used without any modification. After conversion, the data recording section of the current meter contains no moving parts; the storage capacity of the module is equivalent to that of the original tape cartridge.

  9. Effect of vertical motion on current meters

    USGS Publications Warehouse

    Kallio, Nicholas A.

    1966-01-01

    The effect of vertical motion on the performance of current meters at various stream velocities was evaluated to determine whether accurate discharge measurements can be made from a bobbing boat. Three types of current meters--Ott, Price, and vane types--were tested under conditions simulating a bobbing boat. A known frequency and amplitude of vertical motion were imparted to the current meter, and the related effect on the measured stream velocity was determined. One test of the Price meter was made under actual conditions, using a boat and standard measuring gear. The results of the test under actual conditions verified those obtained by simulating the vertical movements of a boat. The tests show that for stream velocities below 2.5 feet per second the accuracy of all three meters is significantly affected when the meters are subjected to certain conditions of vertical motion that can occur during actual field operations. Both the rate of vertical motion and the frequency of vertical oscillation affect the registration of the meter. The results of these tests, presented in the form of graphs and tables, can be used as a guide to determine whether wind and stream flow are within an acceptable range for a reliable discharge measurement from a boat.

  10. Transient eddy current flow metering

    NASA Astrophysics Data System (ADS)

    Forbriger, J.; Stefani, F.

    2015-10-01

    Measuring local velocities or entire flow rates in liquid metals or semiconductor melts is a notorious problem in many industrial applications, including metal casting and silicon crystal growth. We present a new variant of an old technique which relies on the continuous tracking of a flow-advected transient eddy current that is induced by a pulsed external magnetic field. This calibration-free method is validated by applying it to the velocity of a spinning disk made of aluminum. First tests at a rig with a flow of liquid GaInSn are also presented.

  11. Field intercomparisons of electromagnetic current meters

    NASA Astrophysics Data System (ADS)

    Guza, R. T.; Clifton, M. C.; Rezvani, F.

    1988-08-01

    In order to assess the performance of current meters within and near the surf zone, data from biaxial electromagnetic current meters with spherical and open frame probe geometries were intercompared. One bottom-mounted flow meter of each type was deployed in a mean depth of 7.0 m for 17 days, and two sensors of each type were deployed in a mean depth of 2.0 m for 5 days. Sensors in the shallow deployment were frequently in the surf zone. Hourly averaged mean flows measured by different sensor types are highly correlated, averaging above 0.98. The largest difference between measured mean flows is a constant bias, typically about 3.0 cm/s, which is roughly equal to the estimated accuracy of the sensor offset calibrations. Root-mean-square deviations from this constant bias are less than 2.0 cm/s, and are contributed to by errors in both gain calibration and sensor orientation. Comparisons of measured (surface gravity wave) oscillatory currents were made both between current meter types and with velocities inferred from the application of linear theory to pressure sensor data. Correlations between time series of UTrms (the rms total oscillatory velocity for a 1-hour record) were all above 0.99 in 7.0-m depth and averaged 0.95 for the shallow deployment. The average UTrms ratio (over all hour-long records) was within 1.0 ±0.07 for all current meter pairs in both deployments, which is consistent with the estimated 5% uncertainties in the flow meter gain calibration. Typical fluctuations of the UTrms ratio of any spherical and open frame sensor pair about its mean ratio, indicative of flow meter gain distortions probably associated with variations in the hydrodynamic environment, were less than 0.04 for any one deployment. Ratios of UTrms from both deployments taken together suggest that the open frame sensor overresponds, relative to the spherical probe, by about 5% at low (about 10.0 cm/s) total (mean + UTrms) speeds, and underresponds by about 5% at higher total

  12. Comparison of current meters used for stream gaging

    USGS Publications Warehouse

    Fulford, Janice M.; Thibodeaux, Kirk G.; Kaehrle, William R.

    1994-01-01

    The U.S. Geological Survey (USGS) is field and laboratory testing the performance of several current meters used throughout the world for stream gaging. Meters tested include horizontal-axis current meters from Germany, the United Kingdom, and the People's Republic of China, and vertical-axis and electromagnetic current meters from the United States. Summarized are laboratory test results for meter repeatability, linearity, and response to oblique flow angles and preliminary field testing results. All current meters tested were found to under- and over-register velocities; errors usually increased as the velocity and angle of the flow increased. Repeatability and linearity of all meters tested were good. In the field tests, horizontal-axis meters, except for the two meters from the People's Republic of China, registered higher velocity than did the vertical-axis meters.

  13. 26. CURRENT METERS WITH FOLDING SCALE (MEASURED IN INCHES) IN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    26. CURRENT METERS WITH FOLDING SCALE (MEASURED IN INCHES) IN FOREGROUND: GURLEY MODEL NO. 665 AT CENTER, GURLEY MODEL NO. 625 'PYGMY' CURRENT METER AT LEFT, AND WES MINIATURE PRICE-TYPE CURRENT METER AT RIGHT. - Waterways Experiment Station, Hydraulics Laboratory, Halls Ferry Road, 2 miles south of I-20, Vicksburg, Warren County, MS

  14. 25. CURRENT METERS: GURLEY MODEL NO. 665 AT CENTER, GURLEY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    25. CURRENT METERS: GURLEY MODEL NO. 665 AT CENTER, GURLEY MODEL NO. 625 'PYGMY' CURRENT METER AT LEFT, AND WES MINIATURE PRICE-TYPE CURRENT METER AT RIGHT. - Waterways Experiment Station, Hydraulics Laboratory, Halls Ferry Road, 2 miles south of I-20, Vicksburg, Warren County, MS

  15. Repeatability and oblique flow response characteristics of current meters

    USGS Publications Warehouse

    Fulford, Janice M.; Thibodeaux, Kirk G.; Kaehrle, William R.

    1993-01-01

    Laboratory investigation into the precision and accuracy of various mechanical-current meters are presented. Horizontal-axis and vertical-axis meters that are used for the measurement of point velocities in streams and rivers were tested. Meters were tested for repeatability and response to oblique flows. Both horizontal- and vertical-axis meters were found to under- and over-register oblique flows with errors generally increasing as the velocity and angle of flow increased. For the oblique flow tests, magnitude of errors were smallest for horizontal-axis meters. Repeatability of all meters tested was good, with the horizontal- and vertical-axis meters performing similarly.

  16. Response of turbine flow meters to acoustic perturbations

    NASA Astrophysics Data System (ADS)

    Stoltenkamp, P. W.; Bergervoet, J. T. M.; Willems, J. F. H.; van Uittert, F. M. R.; Hirschberg, A.

    2008-08-01

    Acoustic pulsations can have a significant effect on gas turbine flow meters during volume flow measurements. These systematic errors are investigated experimentally for high-frequency pulsations and are compared to the results of a quasi-steady theory. Although significant deviations were found from the quasi-steady theory, the quadratic dependence of the velocity amplitude appears to remain valid for all measurements. The exact quadratic dependence is a function of Strouhal number of the pulsations. In the range of Strouhal numbers below 2.5, based on the chord length at the tip of the rotor blade and the flow velocity at the rotor inlet plane, we find a slow decrease in the error with increasing Strouhal number, Sr. The shape of the leading edge of the rotor blades does not affect this behaviour.

  17. Calibration and maintenance of vertical-axis type current meters

    USGS Publications Warehouse

    Smoot, George F.; Novak, Charles E.

    1968-01-01

    The purpose of this chapter is to describe the procedures used in the manufacture and calibration of current meters and to present in detail information pertinent to their proper maintenance and repair. Recent intensive studies on the calibration of current meters and the effects of wear of the component parts on the performance of the meters have led to the adoption of new procedures for the manufacture, calibration, maintenance, and repair of meters. This chapter, therefore, updates the provisional manual 'Care and Rating of Current Meters' (1957) by including these new procedures.

  18. Modifications to the 4x7 meter tunnel for acoustic research: Engineering feasibility study

    NASA Technical Reports Server (NTRS)

    1986-01-01

    The NASA-Langley Research Center 4 x 7 Meter Low Speed Wind Tunnel is currently being used for low speed aerodynamics, V/STOL aerodynamics and, to a limited extent, rotorcraft noise research. The deficiencies of this wind tunnel for both aerodynamics and aeroacoustics research have been recognized for some time. Modifications to the wind tunnel are being made to improve the test section flow quality and to update the model cart systems. A further modification of the 4 x 7 Meter Wind Tunnel to permit rotorcraft model acoustics research has been proposed. As a precursor to the design of the proposed modifications, NASA is conducted both in-house and contracted studies to define the acoustic environment within the wind tunnel and to provide recommendations or the reduction of the wind tunnel background noise to a level acceptable to acoustics researchers. One of these studies by an acoustics consultant, has produced the primary reference documents that define the wind tunnel noise sources and outline recommended solutions.

  19. 28. LEUPOLD AND STEVENS MIDGET CURRENT METER, WITH FOLDING SCALE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    28. LEUPOLD AND STEVENS MIDGET CURRENT METER, WITH FOLDING SCALE AT TOP, AND THREE VARIATIONS OF WES MINIATURE PRICE-TYPE CURRENT METERS BELOW. - Waterways Experiment Station, Hydraulics Laboratory, Halls Ferry Road, 2 miles south of I-20, Vicksburg, Warren County, MS

  20. Effects of pulsating flow on current meter performance

    USGS Publications Warehouse

    Fulford, Janice M.

    1995-01-01

    Summarized are laboratory tests for current meter response to pulsating flows. Included are results for mechanical and electromagnetic water-current meters that are commonly used for stream gaging. Most of the vertical-axis and horizontal-axis types of mechanical meters that were tested significantly underregistered the mean flow velocity when the magnitude of the pulsating portion of the flow velocity was greater than half the mean velocity but less than the mean velocity. Errors for all meters tested were largest at the lowest mean flow velocity, 0.076 m/s.

  1. Current Measurements and Overwash Monitoring Using Tilt Current Meters in Three Coastal Environments

    NASA Astrophysics Data System (ADS)

    Lowell, N. S.; Sherwood, C. R.; Decarlo, T. M.; Grant, J. R.

    2014-12-01

    Tilt Current Meters (TCMs) provide accurate, cost effective measurements of near-bottom current velocities. Many studies in coastal environments require current measurements, which are frequently made with Acoustic Doppler Profilers (ADPs). ADPs are expensive, however, and may not be suitable for locations where there is significant risk of damage, loss, or theft or where a large spatial array of measurements is required. TCMs, by contrast, are smaller, less expensive, and easier to deploy. This study tested TCMs in three sites to determine their suitability for use in research applications. TCMs are based on the drag-tilt principle, where the instrument tilts in response to current. The meter consists of a buoyant float with an onboard accelerometer, three-axis tilt sensor, three-axis magnetometer (compass), and a data logger. Current measurements are derived by post processing the tilt and compass values and converting them to velocity using empirical calibration data. Large data-storage capacity (4 GB) and low power requirements allow long deployments (many months) at high sample rates (16 Hz). We demonstrate the utility of TCM current measurements on a reef at Dongsha Atoll in the South China Sea, and in Vineyard Sound off Cape Cod, where the TCM performance was evaluated against ADP measurements. We have also used the TCM to record waves during an overwash event on a Cape Cod barrier beach during a winter storm. The TCM recorded waves as they came through the overwash channel, and the data were in agreement with the water-level record used as a reference. These tests demonstrate that TCMs may be used in a variety of near shore environments and have the potential to significantly increase the density of meters in future studies were current measurements are required.

  2. 27. LEUPOLD AND STEVENS MIDGET CURRENT METER (WITH ALTERNATE IMPELLER) ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    27. LEUPOLD AND STEVENS MIDGET CURRENT METER (WITH ALTERNATE IMPELLER) AND FOLDING SCALE (MEASURED IN INCHES). - Waterways Experiment Station, Hydraulics Laboratory, Halls Ferry Road, 2 miles south of I-20, Vicksburg, Warren County, MS

  3. Alternating current electromagnetic servo induction meter

    NASA Technical Reports Server (NTRS)

    Bogue, R. K.

    1968-01-01

    Electromagnetic device accurately indicates the responses of various sensors in high performance flight research aircraft to conditions encountered in flight. The device responds to sensor inputs to move a slideable armature along an indicator scale by the force of currents induced in the armature winding.

  4. Feasibility of using acoustic velocity meters for estimating highly organic suspended-solids concentrations in streams

    USGS Publications Warehouse

    Patino, Eduardo

    1996-01-01

    A field experiment was conducted at the Levee 4 canal site below control structure G-88 in the Everglades agricultural area in northwestern Broward County, Florida, to study the relation of acoustic attenuation to suspended-solids concentrations. Acoustic velocity meter and temperature data were obtained with concurrent water samples analyzed for suspended-solids concentrations. Two separate acoustic velocity meter frequencies were used, 200 and 500 kilohertz, to determine the sensitivity of acoustic attenuation to frequency for the measured suspended-solids concentration range. Suspended-solids concentrations for water samples collected at the Levee 4 canal site from July 1993 to September 1994 ranged from 22 to 1,058 milligrams per liter, and organic content ranged from about 30 to 93 percent. Regression analyses showed that attenuation data from the acoustic velocity meter (automatic gain control) and temperature data alone do not provide enough information to adequately describe the concentrations of suspended solids. However, if velocity is also included as one of the independent variables in the regression model, a satisfactory correlation can be obtained. Thus, it is feasible to use acoustic velocity meter instrumentation to estimate suspended-solids concentrations in streams, even when suspended solids are primarily composed of organic material. Using the most comprehensive data set available for the study (500 kiloherz data), the best fit regression model produces a standard error of 69.7 milligrams per liter, with actual errors ranging from 2 to 128 milligrams per liter. Both acoustic velocity meter transmission frequencies of 200 and 500 hilohertz produced similar results, suggesting that transducers of either frequency could be used to collect attenuation data at the study site. Results indicate that calibration will be required for each acoustic velocity meter system to the unique suspended-solids regime existing at each site. More robust solutions may

  5. A microcomputer based system for current-meter data acquisition

    USGS Publications Warehouse

    Cheng, R.T.; Gartner, J.W.

    1979-01-01

    The U.S. Geological Survey is conducting current measurements as part of an interdisciplinary study of the San Francisco Bay estuarine system. The current meters used in the study record current speed, direction, temperature, and conductivity in digital codes on magnetic tape cartridges. Upon recovery of the current meters, the data tapes are translated by a tape reader into computer codes for further analyses. Quite often the importance of the data processing phase of a current-measurement program is underestimated and downplayed. In this paper a data-processing system which performs the complete data processing and analyses is described. The system, which is configured around an LSI-11 microcomputer, has been assembled to provide the capabilities of data translation, reduction, and tabulation and graphical display immediately following recovery of current meters. The flexibility inherent in a microcomputer has made it available to perform many other research functions which would normally be done on an institutional computer.

  6. Wintertime current meter measurements from the East China Sea

    SciTech Connect

    Trump, C.L.; Burt, W.V.

    1981-09-01

    An array of three current meters were anchored on the continental shelf of the East China Sea during the last half of February 1975 as part of the Japanese Air Mass Transformation Experiment, AMTEX-75. The results indicate that the currents are dominated by the rotational semidiurnal M/sub 2/ tidal component superimposed on a slow mean drift to the northeast. Differences in direction of several days duration between two of the current meters suggest the presence of transient mesoscale eddies or meanders in the flow regime.

  7. Note: A real-time beam current density meter

    SciTech Connect

    Liu Junliang; Yu Deyang; Ruan Fangfang; Xue Yingli; Wang Wei

    2013-03-15

    We have developed a real-time beam current density meter for charged particle beams. It measures the mean current density by collimating a uniform and large diameter primary beam. The suppression of the secondary electrons and the deflection of the beam were simulated, and it was tested with a 105 keV Ar{sup 7+} ion beam.

  8. Accuracy of acoustic velocity metering systems for measurement of low velocity in open channels

    USGS Publications Warehouse

    Laenen, Antonius; Curtis, R.E., Jr.

    1989-01-01

    Acoustic velocity meter (AVM) accuracy depends on equipment limitations, the accuracy of acoustic-path length and angle determination, and the stability of the mean velocity to acoustic-path velocity relation. Equipment limitations depend on path length and angle, transducer frequency, timing oscillator frequency, and signal-detection scheme. Typically, the velocity error from this source is about +or-1 to +or-10 mms/sec. Error in acoustic-path angle or length will result in a proportional measurement bias. Typically, an angle error of one degree will result in a velocity error of 2%, and a path-length error of one meter in 100 meter will result in an error of 1%. Ray bending (signal refraction) depends on path length and density gradients present in the stream. Any deviation from a straight acoustic path between transducer will change the unique relation between path velocity and mean velocity. These deviations will then introduce error in the mean velocity computation. Typically, for a 200-meter path length, the resultant error is less than one percent, but for a 1,000 meter path length, the error can be greater than 10%. Recent laboratory and field tests have substantiated assumptions of equipment limitations. Tow-tank tests of an AVM system with a 4.69-meter path length yielded an average standard deviation error of 9.3 mms/sec, and the field tests of an AVM system with a 20.5-meter path length yielded an average standard deviation error of a 4 mms/sec. (USGS)

  9. Field evaluation of an electromagnetic current meter based vertical profiler

    NASA Astrophysics Data System (ADS)

    Hamblin, P. F.; Marmoush, Y. M. R.; Boyce, F. M.; Smith, A. A.

    1987-10-01

    A current profiler consisting of a vertical array of three electromagnetic current meters has been evaluated through an intercomparison of the three sensors, with reference to nearby current and wave data and by comparison to recent laboratory performance tests (Aubrey and Trowbridge, 1985). Mean flow estimates are too uncertain and variable to allow bottom boundary layer shear stress to be estimated by the conventional logarithmic law method. As well as unexplained sudden shifts in the mean speed response, the comparison with vector-averaged current meter data indicates possible long-term reduction in response due to fouling of the sensors by biological growth. The directional response was less sensitive to fouling effects. The oscillatory response on one occasion after field deployment for 17 days indicates a reduction in response from 41 to 45% at a period of oscillation of 3 s in a combined steady and oscillatory flow field. This study demonstrates that despite careful laboratory calibration, electromagnetic current meters are not at present suitable for quantitative study of dynamics of sediment resuspension in near-bottom shallow-water environments.

  10. Voltage-current-power meter for photovoltaic solar arrays

    NASA Technical Reports Server (NTRS)

    Ross, Ronald G. (Inventor)

    1979-01-01

    A meter is disclosed for measuring the voltage, current, and power (VIP) parameters of a photovoltaic solar array, or array module, under sunlight operating conditions utilizing a variable load connected across the array and controlled by a voltage regulator which responds to the difference between the output voltage of the array and a programmed test voltage from a source which generates a single ramp voltage for measuring and recording current as a function of voltage, repeated ramp voltages at a high rate for peak output measurements or a DC voltage for VIP measurements at selected points on the I-V characteristic curve of the array. The voltage signal from a current sensing element, such as a shunt resistor in series with the variable load, is compared with the output current of a reference solar cell to provide a normalizing signal to be added to the signal from the current-sensing element in order to provide a record of array current as a function of array voltage, i.e., for all load conditions from short circuit to open circuit. As the normalized current is thus measured, an analog multiplier multiplies the array voltage and normalized current to provide a measurement of power. Switches are provided to selectively connect the power, P, current, I, or voltage, V, to a meter, directly or through a peak detector. At the same time any one of the parameters V, I and P may be recorded as a function of any other parameter.

  11. Broad-band acoustic Doppler current profiler

    USGS Publications Warehouse

    Cobb, E.D.

    1993-01-01

    The broad-band acoustic Doppler current profiler is an instrument that determines velocity based on the Doppler principle by reflecting acoustic signals off sediment particles in the water. The instrument is capable of measuring velocity magnitude and direction throughout a water column and of measuring water depth. It is also capable of bottom tracking and can, therefore, keep track of its own relative position as it is moved across a channel. Discharge measurements can be made quickly and, based on limited tests, accurately with this instrument. ?? 1993.

  12. LLNL current meter array--concept and system description

    SciTech Connect

    Mantrom, D.D.

    1994-11-15

    A measurement capability using a horizontal array of 10 S4 current meters mounted on a stiff floating structure with 35 m aperture has been developed to support interpretation of radar imaging of surface effects associated with internal waves. This system has been fielded three times and most recently, has collected data alongside the sea-surface footprint of a land-fixed radar imaging ship-generated internal waves. The underlying need for this measurement capability is described. The specifications resulting from this need are presented and the engineering design and deployment procedures of the platform and systems that resulted are described The current meter data are multiplexed along with meteorological and system status data on board the floating platform and are telemetered to a shore station and on to a data acquisition system. The raw data are recorded, and are then processed to form space-time images of current and strain rate (a spatial derivative of the current field). Examples of raw and processed data associated with ship-generated internal waves are presented.

  13. Acoustic treatment of the NASA Langley 4- by 7-meter tunnel: A feasibility study

    NASA Technical Reports Server (NTRS)

    Yu, J. C.; Abrahamson, A. L.

    1986-01-01

    A feasibility study for upgrading the NASA Langley 4- by 7-Meter Tunnel so that it may be used for aeroacoustic research related to helicopters is described. The requirements for noise research leading to the design of the next generation of helicopters impose a set of acoustic test criteria that no existing wind tunnel in the United States can presently meet. Included in this feasibility study are the following considerations: (1) an evaluation of general wind-tunnel requirements and desired tunnel background noise levels for helicopter aeroacoustic research; (2) an assessment of the present acoustic environment for testing model rotors; (3) a diagnostic investigation of tunnel background noise sources and paths; (4) acoustic treatment options for tunnel background noise reduction and a trade-off study between these options; (5) an engineering feasibility assessment of the selected option; and (6) an integrated analysis of study components and recommendations of treatment for an approach to meet the tunnel background noise reduction goal. It is concluded that the Langley 4- by 7-Meter Tunnel is a fundamentally suitable facility for helicopter aeroacoustic research. It is also concluded that acoustic treatment of this facility for meeting the required tunnel background noise goal can be accomplished technically at reasonable risk and cost.

  14. Field intercomparison of three current meters in an environment free from high frequency motion

    NASA Astrophysics Data System (ADS)

    Larouche, Pierre; Deguise, Jean-Claude

    1989-06-01

    An intercomparison of three different types of current meter was performed in an Arctic environment where wave action was absent, permitting the evaluation of the instruments under natural conditions of weak currents and cold water. The instruments were an Aanderaa RCMS4S, an Inter Ocean S4 and an EG&G-Neil Brown Smart Acoustic Current Meter (SACM). The S4 and the SACM both showed their ability to measure very small currents as opposed to the RCM4S which is limited by a mechanical rotor threshold. The agreement of the direction was better between the RCM4S and the SACM than between the RCM4S and the S4. Due to the misalignment of the Aanderaa vane in very weak currents, direction differences between the instruments of either pair can, however, reach 180°. The misalignment also shields the Aanderaa rotor leading to underestimation of current speed. The threshold for a good speed reading for the Aanderaa can be put conservatively at 5 cm s -1. Above this value, the RCM4S over-responded compared to both the S4 and the SACM. The source of that problem seems to be related to different calibrations of the instruments. Finally a power spectrum analysis showed that the RCM4S, when not influenced by wave action, can produce a measure of the energy as good as that of a vector averaging instrument.

  15. Thirty Meter Telescope: current operations concepts and plans

    NASA Astrophysics Data System (ADS)

    Silva, David R.

    2008-07-01

    The Thirty Meter Telescope (TMT) will be a ground-based, 30-m optical-IR telescope with a highly segmented primary mirror located in a remote location. From the start of operations, TMT will provide a rich and diverse mix of seeing-limited and diffraction-limited instrumentation. Initially, only classical observing will be supported, although remote observing will follow almost immediately. Queue (or service) observing may be supported at a later date. TMT users will expect high facility uptime and observing efficiency as well as effective user support for planning and execution of observations. Those expectations are captured in the high-level Operations Concept Definition (OCD) document. The services and staffing needed to implement those concepts are described in the TMT Operations Plan. In this paper, high-level TMT operational concepts are summarized followed by a description of the current operations plan, including staffing model.

  16. Design, fabrication and acoustic tests of a 36 inch (0.914 meter) statorless turbotip fan

    NASA Technical Reports Server (NTRS)

    Smith, E. G.; Stempert, D. L.; Uhl, W. R.

    1975-01-01

    The LF336/E is a 36 inch (0.914 meter) diameter fan designed to operate in a rotor-alone configuration. Design features required for modification of the existing LF336/A rotor-stator fan into the LF336/E statorless fan configuration are discussed. Tests of the statorless fan identified an aerodynamic performance deficiency due to inaccurate accounting of the fan exit swirl during the aerodynamic design. This performance deficiency, related to fan exit static pressure levels, produced about a 20 percent thrust loss. A study was then conducted for further evaluation of the fan exit flow fields typical of statorless fan systems. This study showed that through proper selection of fan design variables such as pressure ratio, radius ratio, and swirl distributions, performance of a statorless fan configuration could be improved with levels of thrust approaching the conventional rotor-stator fan system. Acoustic measurements were taken for the statorless fan system at both GE and NASA, and when compared to other lift fan systems, showed noise levels comparable to the quietest lift fan configuration which included rotor-stator spacing and acoustic treatment. The statorless fan system was also used to determine effects of rotor leading edge serrations on noise generations. A cascade test program identified the serration geometry based on minimum pressure losses, wake turbulence levels and noise generations.

  17. Price current-meter standard rating development by the U.S. geological survey

    USGS Publications Warehouse

    Hubbard, E.F.; Schwarz, G.E.; Thibodeaux, K.G.; Turcios, L.M.

    2001-01-01

    The U.S. Geological Survey has developed new standard rating tables for use with Price type AA and pygmy current meters, which are employed to measure streamflow velocity. Current-meter calibration data, consisting of the rates of rotation of meters at several different constant water velocities, have shown that the original rating tables are no longer representative of the average responsiveness of newly purchased meters or meters in the field. The new rating tables are based on linear regression equations that are weighted to reflect the population mix of current meters in the field and weighted inversely to the variability of the data at each calibration velocity. For calibration velocities of 0.3 m/s and faster, at which most streamflow measurements are made, the new AA-rating predicts the true velocities within 1.5% and the new pygmy-meter rating within 2.0% for more than 95% of the meters. At calibration velocities, the new AA-meter rating is up to 1.4% different from the original rating, and the new pygmy-meter rating is up to 1.6% different.

  18. SonTek SL3G Side-Looking Doppler Current Meter application in Complex Flow Conditions

    NASA Astrophysics Data System (ADS)

    Wagenaar, D.

    2014-12-01

    The SonTek Argonaut SL Side-Looking Doppler Current Meters are well established products in the measurement of real-time water velocity in open channels. With the development of acoustic doppler technology the decision was made to incorporate latest technology in the Argonaut SL and hence the SonTek SL3G was born.The SonTek SL3G Acoustic Doppler instrument incorporates a number of innovations that improves velocity measurements and quality assurance of data for Side-Looking Doppler Current Meters. SmartPulseHD was originally introduced with the launch of the SonTek M9/S5 RiverSurveyor Acoustic Doppler Instruments and the increased accuracy and resolution of velocity measurements made it obvious to include into the new SL3G instruments. SmartPulseHD continuously tracks the water conditions and selects the optimum processing configuration required using multiple ping types and processing techniques. The new SL3G design makes it the smallest Side Looking Acoustic Doppler Velocity Meter on the market reducing flow disturbance caused by the instrument and the distance of first measurement cell from boundary.The application of the SL3G Acoustic Doppler instrument is designed for complex flow conditions where the use of conventional stage-discharge relationships is economically not viable and therefore requires the use of velocity index methodology. The case-study presented in this paper is situated in the Colorado River downstream of Imperial Dam affected by controlled releases, drainage from adjacent irrigation areas and backwater from a weir situated downstream of the monitoring site. The paper analyses the relationship between measured mean velocity and index velocity and if additional variables such as stage and or Y-velocity need to be incorporated in the development of the index velocity rating. In addition, to determine the variables impacting on the index velocity rating, the index velocity applied will be evaluated by the best linear relationship between the

  19. An evaluation of proposed acoustic treatments for the NASA LaRC 4 x 7 meter wind tunnel

    NASA Technical Reports Server (NTRS)

    Abrahamson, A. L.

    1985-01-01

    The NASA LaRC 4 x 7 Meter Wind Tunnel is an existing facility specially designed for powered low speed (V/STOL) testing of large scale fixed wing and rotorcraft models. The enhancement of the facility for scale model acoustic testing is examined. The results are critically reviewed and comparisons are drawn with a similar wind tunnel (the DNW Facility in the Netherlands). Discrepancies observed in the comparison stimulated a theoretical investigation using the acoustic finite element ADAM System, of the ways in which noise propagating around the tunnel circuit radiates into the open test section. The reasons for the discrepancies noted above are clarified and assists in the selection of acoustic treatment options for the facility.

  20. Discharge Measurements in Shallow Urban Streams Using a Hydroacoustic Current Meter

    USGS Publications Warehouse

    Fisher, G.T.; Morlock, S.E.

    2002-01-01

    Hydroacoustic current-meter measurements were evaluated in small urban streams under a range of stages, velocities, and channel-bottom materials. Because flow in urban streams is often shallow, conventional mechanical current-meter measurements are difficult or impossible to make. The rotating-cup Price pygmy meter that is widely used by the U.S. Geological Survey and other agencies should not be used in depths below 0.20 ft and velocities less than 0.30 ft/s. The hydroacoustic device provides measurements at depths as shallow as 0.10 ft and velocities as low as 0.10 ft/s or less. Measurements using the hydroacoustic current meter were compared to conventional discharge measurements. Comparisons with Price-meter measurements were favorable within the range of flows for which the meters are rated. Based on laboratory and field tests, velocity measurements with the hydroacoustic cannot be validated below about 0.07 ft/s. However, the hydroacoustic meter provides valuable information on direction and magnitude of flow even at lower velocities, which otherwise could not be measured with conventional measurements.

  1. Generation of currents in the solar atmosphere by acoustic waves

    NASA Astrophysics Data System (ADS)

    Riutov, D. D.; Riutova, M. P.

    The novel mechanism presented for current and magnetic field generation by acoustic-wave fluxes in solar plasmas is especially potent in the region where acoustic-wave damping is due to such nonlinear effects as weak-shock formation. An evaluation is made of the significance of this effect for the solar atmosphere, under the proviso that this treatment is restricted to effects due to the usual acoustic waves. Wave absorption is governed by the classical collisional effects of thermal conductivity, viscosity, and ohmic losses.

  2. Extending and expanding the life of older current meters

    USGS Publications Warehouse

    Strahle, W.J.; Martini, M.A.

    1995-01-01

    The EG&G Model 610 VACM and Model 630 VMCM are standards for ocean current measurements. It is simple to add peripheral sensors to the data stream of the VACM by use of add-on CMOS circuitry. The firmware control of the VMCM makes it virtually impossible to add sampling of additional sensors. Most of the electronic components used in the VACM are obsolete or difficult to replace and the VMCM will soon follow suit. As a result, the USGS joined WHOI in the development of a PCMCIA data storage system to replace the cassette recording system in the VACM. Using the same PCMCIA recording package as the controller and recorder for the VMCM, a user-friendly VMCM is being designed. PCMCIA cards are rapidly becoming an industry standard with a wide range of storage capacities. By upgrading the VACM and VMCM to PCMCIA storage systems with a flexible microprocessor, they will continue to be viable instruments.

  3. Overview of hydro-acoustic current-measurement applications by the U.S. geological survey in Indiana

    USGS Publications Warehouse

    Morlock, Scott E.; Stewart, James A.

    1999-01-01

    The U.S. Geological Survey (USGS) maintains a network of 170 streamflow-gaging stations in Indiana to collect data from which continuous records of river discharges are produced. Traditionally, the discharge record from a station is produced by recording river stage and making periodic discharge measurements through a range of stage, then developing a relation between stage and discharge. Techniques that promise to increase data collection accuracy and efficiency include the use of hydro-acoustic instrumentation to measure river velocities. The velocity measurements are used to compute river discharge. In-situ applications of hydro-acoustic instruments by the USGS in Indiana include acoustic velocity meters (AVM's) at six streamflow-gaging stations and newly developed Doppler velocity meters (DVM's) at two stations. AVM's use reciprocal travel times of acoustic signals to measure average water velocities along acoustic paths, whereas DVM's use the Doppler shift of backscattered acoustic signals to compute water velocities. In addition to the in-situ applications, three acoustic Doppler current profilers (ADCP's) are used to make river-discharge measurements from moving boats at streamflow-gaging stations in Indiana. The USGS has designed and is testing an innovative unmanned platform from which to make ADCP discharge measurements.

  4. Current profilers and current meters: compass and tilt sensors errors and calibration

    NASA Astrophysics Data System (ADS)

    Le Menn, M.; Lusven, A.; Bongiovanni, E.; Le Dû, P.; Rouxel, D.; Lucas, S.; Pacaud, L.

    2014-08-01

    Current profilers and current meters have a magnetic compass and tilt sensors for relating measurements to a terrestrial reference frame. As compasses are sensitive to their magnetic environment, they must be calibrated in the configuration in which they will be used. A calibration platform for magnetic compasses and tilt sensors was built, based on a method developed in 2007, to correct angular errors and guarantee a measurement uncertainty for instruments mounted in mooring cages. As mooring cages can weigh up to 800 kg, it was necessary to find a suitable place to set up this platform, map the magnetic fields in this area and dimension the platform to withstand these loads. It was calibrated using a GPS positioning technique. The platform has a table that can be tilted to calibrate the tilt sensors. The measurement uncertainty of the system was evaluated. Sinusoidal corrections based on the anomalies created by soft and hard magnetic materials were tested, as well as manufacturers’ calibration methods.

  5. COMPARISON OF RECORDING CURRENT METERS USED FOR MEASURING VELOCITIES IN SHALLOW WATERS OF SAN FRANCISCO BAY, CALIFORNIA.

    USGS Publications Warehouse

    Gartner, Jeffrey W.; Oltmann, Richard N.

    1985-01-01

    The authors determine the feasibility of collecting reliable current-meter data in shallow water under natural conditions. The study involved field testing four types of recording current meters (different speed sensors) and comparing data recorded by the meters under different field conditions. Speeds recorded by the current meters at slack water and during maximum flows were compared during calm and windy conditions at various tide levels.

  6. Comparison of a few recording current meters in San Francisco Bay, CA

    USGS Publications Warehouse

    Cheng, R.T.

    1978-01-01

    A team of research scientists in the U.S. Geological Survey uses San Francisco Bay, California, as an outdoor laboratory to study complicated interactions of physical, chemical, and biological processes which take place in an estuarine environment. A current meter comparison study was conceived because of the need to select a suitable current meter to meet field requirements for current measurements in the Bay. The study took place in south San Francisco Bay, California, in the spring of 1977. An instrument tower which was designed to support instruments free from the conventional mooring line motions was constructed and emplaced in south San Francisco Bay. During a period of two months, four types of recording current meters have been used in the tests. The four types were: (1) Aanderaa, (2) tethered shroud-impeller, (3) drag-inclinometer, and (4) electromagnetic current meters. With the exception of the electromagnetic current meter, one of each type was mounted on the instrument tower, and one of each type was deployed on moorings near the instrument tower. In addition, a wind anemometer and a recording tide gauge were also installed on the tower. This paper discusses the characteristics of each instrument and the accuracy that each instrument can provide when used in an estuarine environment. We pay special attention to our experiences in the field operation with respect to handling of the instruments and to our experiences working up the raw data in the post-deployment data analysis.

  7. Tuning Coler Magnetic Current Apparatus with Magneto-Acoustic Resonance

    NASA Astrophysics Data System (ADS)

    Ludwig, Thorsten

    An attempt was made to tune the Coler magnetic current apparatus with the magneto acoustic resonance of the magnetic rods. Measurements with a replica of the famous Coler "Magnetstromapparat" were conducted. In order to tune the acoustic, magnetic and electric resonance circuits of the Coler device the magneto-acoustic resonance was measured with a frequency scan through a function generator and a lock-in amplifier. The frequency generator was powering a driving coil, while the lock-in was connected to a pickup coil. Both coils were placed on a magnetic rod. Resonances were observed up to the 17th harmonic. The quality Q of the observed resonances was 270. To study the magneto-acoustic resonance in the time domain a pair of Permendur rods were employed. The magneto-acoustic resonances of the Permendur rods were observed with an oscilloscope. Spectra of the magneto acoustic resonance were measured for the Permendur rods and for a Coler replica magnet in the frequency range from 25 kHz to 380 kHz. The next step was to bring the resonances of the Permendur rods close together so that they overlap. The 10thharmonic was chosen because it was close to the 180 kHz that Hans Coler related to ferromagnetism. Further more magneto-acoustic coupling between the Permendur rods was studied. Finally the question was explored if Hans Coler converted vacuum fluctuations via magnetic and acoustic resonance into electricity. There is a strong connection between magnetism and quantum field zero point energy (ZPE). An outlook is given on next steps in the experiments to unveil the working mechanism of the Coler magnetic current apparatus.

  8. Analysis of Acoustic Wave and Current Data Offshore of Mytle Beach, South Carolina

    NASA Astrophysics Data System (ADS)

    Fall, K. A.; Wren, A.

    2008-12-01

    Two bottom boundary layer (BBL) instrument frames have been deployed on the shoreface and inner-shelf of Long Bay, South Carolina offshore of Myrtle Beach as part of a South Carolina Sea Grant funded project to measure sediment transport over two hardbottom habitats. The inshore instrument frame is located on an extensive hardbottom surface 850 meters offshore. The second instrumented frame is secured to a hardbottom surface on the inner-shelf at a distance of approximately 2.5 km offshore. The nearshore BBL observing system is composed of a downward-looking RDI/ Teledyne 1200 kHz Pulse-Coherent Acoustic Doppler Current Profiler, an upward-looking Nortek Acoustic Wave and Current Profiler (AWAC), and an Aquatec Acoustic Backscatter Sensor. As part of this larger study, the wave and current data from the AWAC have been analyzed. Long-term continuous time series data include wave height, wave period, directional wave spectra, and the magnitude and direction of currents in the water column. Within the data set are several wave events, including several frontal passages and Tropical Storm Hanna which hit the Myrtle Beach area in early September. Wave data have been correlated with meteorological data, and a comparison of shoreface wave characteristics during each type of event are presented.

  9. Evaluation of acoustic doppler velocity meters to quantify flow from Comal Springs and San Marcos Springs, Texas

    USGS Publications Warehouse

    Gary, Marcus O.; Gary, Robin H.; Asquith, William H.

    2008-01-01

    Comal Springs and San Marcos Springs are the two largest springs in Texas, are major discharge points for the San Antonio segment of the Edwards aquifer, and provide habitat for several Federally listed endangered species that depend on adequate springflows for survival. It is therefore imperative that the Edwards Aquifer Authority have accurate and timely springflow data to guide resource management. Discharge points for Comal Springs and San Marcos Springs are submerged in Landa Lake and in Spring Lake, respectively. Flows from the springs currently (2008) are estimated by the U.S Geological Survey in real time as surface-water discharge from conventional stage-discharge ratings at sites downstream from each spring. Recent technological advances and availability of acoustic Doppler velocity meters (ADVMs) now provide tools to collect data (stream velocity) related to springflow that could increase accuracy of real-time estimates of the springflows. The U.S. Geological Survey, in cooperation with the Edwards Aquifer Authority, did a study during May 2006 through September 2007 to evaluate ADVMs to quantify flow from Comal and San Marcos Springs. The evaluation was based on two monitoring approaches: (1) placement of ADVMs in important spring orifices - spring run 3 and spring 7 at Comal Springs, and diversion spring at San Marcos Springs; and (2) placement of ADVMs at the nearest flowing streams - Comal River new and old channels for Comal Springs, Spring Lake west and east outflow channels and current (2008) San Marcos River streamflow-gaging site for San Marcos Springs. For Comal Springs, ADVM application at spring run 3 and spring 7 was intended to indicate whether the flows of spring run 3 and spring 7 can be related to total springflow. The findings indicate that velocity data from both discharge features, while reflecting changes in flow, do not reliably show a direct relation to measured streamflow and thus to total Comal Springs flow. ADVMs at the Comal

  10. Measuring the Kuroshio Current with ocean acoustic tomography.

    PubMed

    Taniguchi, Naokazu; Huang, Chen-Fen; Kaneko, Arata; Liu, Cho-Teng; Howe, Bruce M; Wang, Yu-Huai; Yang, Yih; Lin, Ju; Zhu, Xiao-Hua; Gohda, Noriaki

    2013-10-01

    Ocean current profiling using ocean acoustic tomography (OAT) was conducted in the Kuroshio Current southeast of Taiwan from August 20 to September 15, 2009. Sound pulses were transmitted reciprocally between two acoustic stations placed near the underwater sound channel axis and separated by 48 km. Based on the result of ray simulation, the received signals are divided into multiple ray groups because it is difficult to resolve the ray arrivals for individual rays. The average differential travel times from these ray groups are used to reconstruct the vertical profiles of currents. The currents are estimated with respect to the deepest water layer via two methods: An explicit solution and an inversion with regularization. The strong currents were confined to the upper 200 m and rapidly weakened toward 500 m in depth. Both methods give similar results and are consistent with shipboard acoustic Doppler current profiler results in the upper 150 m. The observed temporal variation demonstrates a similar trend to the prediction from the Hybrid Coordinate Ocean Model. PMID:24116522

  11. Near-surface current meter array measurements of internal gravity waves

    SciTech Connect

    Jones, H.B.E.

    1994-11-15

    We have developed various processing algorithms used to estimate the wave forms produced by hydrodynamic Internal Waves. Furthermore, the estimated Internal Waves are used to calculate the Modulation Transfer Function (MTF) which relates the current and strain rate subsurface fields to surface scattering phenomenon imaged by radar. Following a brief discussion of LLNL`s measurement platform (a 10 sensor current meter array) we described the generation of representative current and strain rate space-time images from measured or simulated data. Then, we present how our simulation capability highlighted limitations in estimating strain rate. These limitations spurred the application of beamforming techniques to enhance our estimates, albeit at the expense of collapsing our space-time images to 1-D estimates. Finally, we discuss progress with regard to processing the current meter array data captured during the recent Loch Linnhe field trials.

  12. Effects of simulated ice on the performance of price type-AA current meter rotors

    USGS Publications Warehouse

    Fulford, Janice M.

    1994-01-01

    Slush ice readily adheres to the standard metal rotor of the winter Price type-AA current meter and affects the ability of the meter to measure the flow velocity accurately. Tests conducted at the U.S. Geological Survey Hydraulics Laboratory at Stennis Space Center, Mississippi, attempt to quantify the effects of slush ice on the performance of standard Price type-AA meter metal rotors. Test data obtained for rotors filled with simulated slush are compared with data for solid-cup polymer and standard hollow-cup metal rotors. Partial filling of the cups only marginally affects rotor performance at velocities greater than 15.24 centimeters per second. However, when cups are filled or over-filled with simulated slush, rotor performance is noticeably affected. Errors associated with slush over-filling and filling of cups are also significant when flows are angled vertically.

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

    PubMed

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

    2013-09-01

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

  14. Ion acoustic solitons in Earth's upward current region

    SciTech Connect

    Main, D. S.; Scholz, C.; Newman, D. L.; Ergun, R. E.

    2012-07-15

    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.

  15. Current meter data report, September 1980 - December 1980: mooring OTEC-HB

    SciTech Connect

    Roman, T M; Wang, D P

    1981-03-01

    Data tapes contained current meter records from instrumented mooring OTEC-HB near the OTEC-1 site approximately 14 nautical miles northwest of Keahole Point, Island of Hawaii. Deployed in 1345 m of water, the mooring had five Aanderaa RCM-5 current meters, one at each of the following depths: 47 m, 70m, 99m, 154m, and 829 m. Raw data consisted of east-west (U) velocity, north-south (V) velocity, temperature (T), and pressure (P) time series from September 23, 1980, through December 20, 1980, with a recording interval of 15 min. The series (U, V, T) were filtered into various frequency domains, thereby removing very high frequencies and separating tidal oscillations from very low frequencies. Spectral analyses were performed on the nontidal U and V time series.

  16. Feasibility of Acoustic Doppler Velocity Meters for the Production of Discharge Records from U.S. Geological Survey Streamflow-Gaging Stations

    USGS Publications Warehouse

    Morlock, Scott E.; Nguyen, Hieu T.; Ross, Jerry H.

    2002-01-01

    It is feasible to use acoustic Doppler velocity meters (ADVM's) installed at U.S. Geological Survey (USGS) streamflow-gaging stations to compute records of river discharge. ADVM's are small acoustic current meters that use the Doppler principle to measure water velocities in a two-dimensional plane. Records of river discharge can be computed from stage and ADVM velocity data using the 'index velocity' method. The ADVM-measured velocities are used as an estimator or 'index' of the mean velocity in the channel. In evaluations of ADVM's for the computation of records of river discharge, the USGS installed ADVM's at three streamflow-gaging stations in Indiana: Kankakee River at Davis, Fall Creek at Millersville, and Iroquois River near Foresman. The ADVM evaluation study period was from June 1999 to February 2001. Discharge records were computed, using ADVM data from each station. Discharge records also were computed using conventional stage-discharge methods of the USGS. The records produced from ADVM and conventional methods were compared with discharge record hydrographs and statistics. Overall, the records compared closely from the Kankakee River and Fall Creek stations. For the Iroquois River station, variable backwater was present and affected the comparison; because the ADVM record compensates for backwater, the ADVM record may be superior to the conventional record. For the three stations, the ADVM records were judged to be of a quality acceptable to USGS standards for publications and near realtime ADVM-computed discharges are served on USGS real-time data World Wide Web pages.

  17. Feasibility of using an acoustic velocity meter to measure flow in the Chipps Island channel, Suisun Bay, California

    USGS Publications Warehouse

    Hoffard, Stuart H.

    1980-01-01

    Tests were conducted in 1978 to determine the feasibility of using an acoustic velocity meter to measure the Sacramento-San Joaquin Delta outflow in the Chipps Island Channel, Suisun Bay, Calif. Three parts of transducers with frequencies of 100, 40, and 24 kilohertz were installed on a cross-channel test path and operated at three elevations, 15.5, 8.0, and 4.0 feet below mean lower low water, to test signal transmission at varying depths. Transmission was most reliable at the lowest depth, and the 24-kilohertz transducers at the 7-millivolt threshold of signal strength met the study 's criterion of no persistent signal loss of more than one hour 's duration in any phase of the tidal cycle. Signal strength was statistically correlated with the environmental factors of wind velocity, wind direction, solar insolation, electrical conductivity, water temperature, water velocity, stage, rate of change in stage, and the acceleration of the rate of change in stage. All correlations were weak. Signal strength is apparently a function of the interaction of several environmental factors. A 32-day test to observe if aquatic growth on the transducers would affect signal transmission showed no reduction in signal strength. Suspended-sediment samples indicated that both the size and concentration of particles are greater than presumed in earlier studies. According to the results of this study, chances are good for reliable transmission of acoustic velocity meter signals. Usually some signals were much stronger than the average 20-second signal strength at 15-minute intervals used for correlation and the frequency analysis. Superior equipment is now being developed specifically for the Chipps Island site to transmit signals several times stronger than the signals analyzed in these tests. (USGS)

  18. Application of acoustic velocity meters for gaging discharge of three low-velocity tidal streams in the St. Johns River basin, northeast Florida

    USGS Publications Warehouse

    Sloat, J.V.; Gain, W.S.

    1995-01-01

    Index-velocity data collected with acoustic velocity meters, stage data, and cross-sectional area data were used to calculate discharge at three low-velocity, tidal streamflow stations in north-east Florida. Discharge at three streamflow stations was computed as the product of the channel cross-sectional area and the mean velocity as determined from an index velocity measured in the stream using an acoustic velocity meter. The tidal streamlflow stations used in the study were: Six Mile Creek near Picolata, Fla.; Dunns Creek near Satsuma, Fla.; and the St. Johns River at Buffalo Bluff. Cross-sectional areas at the measurement sections ranged from about 3,000 square feet at Six Mile Creek to about 18,500 square feet at St. Johns River at Buffalo Bluff. Physical characteristics for all three streams were similar except for drainage area. The topography primarily is low-relief, swampy terrain; stream velocities ranged from about -2 to 2 feet per second; and the average change in stage was about 1 foot. Instantaneous discharge was measured using a portable acoustic current meter at each of the three streams to develop a relation between the mean velocity in the stream and the index velocity measured by the acoustic velocity meter. Using least-squares linear regression, a simple linear relation between mean velocity and index velocity was determined. Index velocity was the only significant linear predictor of mean velocity for Six Mile Creek and St. Johns River at Buffalo Bluff. For Dunns Creek, both index velocity and stage were used to develop a multiple-linear predictor of mean velocity. Stage-area curves for each stream were developed from bathymetric data. Instantaneous discharge was computed by multiplying results of relations developed for cross-sectional area and mean velocity. Principal sources of error in the estimated discharge are identified as: (1) instrument errors associated with measurement of stage and index velocity, (2) errors in the representation of

  19. Measurement of Turbulence with Acoustic Doppler Current Profilers - Sources of Error and Laboratory Results

    USGS Publications Warehouse

    Nystrom, E.A.; Oberg, K.A.; Rehmann, C.R.

    2002-01-01

    Acoustic Doppler current profilers (ADCPs) provide a promising method for measuring surface-water turbulence because they can provide data from a large spatial range in a relatively short time with relative ease. Some potential sources of errors in turbulence measurements made with ADCPs include inaccuracy of Doppler-shift measurements, poor temporal and spatial measurement resolution, and inaccuracy of multi-dimensional velocities resolved from one-dimensional velocities measured at separate locations. Results from laboratory measurements of mean velocity and turbulence statistics made with two pulse-coherent ADCPs in 0.87 meters of water are used to illustrate several of inherent sources of error in ADCP turbulence measurements. Results show that processing algorithms and beam configurations have important effects on turbulence measurements. ADCPs can provide reasonable estimates of many turbulence parameters; however, the accuracy of turbulence measurements made with commercially available ADCPs is often poor in comparison to standard measurement techniques.

  20. Near-surface current meter array measurements of internal gravity waves

    SciTech Connect

    Mantrom, D.D.; Jones, H.E.; Chambers, D.H.

    1994-11-03

    A measurement capability using a horizontal array of 10 S4 current meters mounted on a stiff floating structure with 35m aperture has been developed to support interpretation of radar imaging of surface effects associated with internal gravity waves. This system has been fielded three times and most recently, has collected data alongside the sea-surface footprint of a land-fixed radar imaging ship-generated internal waves. The underlying need for this measurement capability is described. The specifications resulting from this need are presented and the engineering design and deployment procedures of the platform and systems that resulted are described. The current meter data are multiplexed along with meteorological and system status data onboard the floating platform and are telemetered to a shore station and on to a data acquisition system. The raw data are recorded, and are then processed to form space-time images of current and strain rate (a spatial derivative of the current field). Examples of raw and processed data associated with ship-generated internal waves are presented.

  1. Discharge measurements using a broad-band acoustic Doppler current profiler

    USGS Publications Warehouse

    Simpson, Michael R.

    2002-01-01

    The measurement of unsteady or tidally affected flow has been a problem faced by hydrologists for many years. Dynamic discharge conditions impose an unreasonably short time constraint on conventional current-meter discharge-measurement methods, which typically last a minimum of 1 hour. Tidally affected discharge can change more than 100 percent during a 10-minute period. Over the years, the U.S. Geological Survey (USGS) has developed moving-boat discharge-measurement techniques that are much faster but less accurate than conventional methods. For a bibliography of conventional moving-boat publications, see Simpson and Oltmann (1993, page 17). The advent of the acoustic Doppler current profiler (ADCP) made possible the development of a discharge-measurement system capable of more accurately measuring unsteady or tidally affected flow. In most cases, an ADCP discharge-measurement system is dramatically faster than conventional discharge-measurement systems, and has comparable or better accuracy. In many cases, an ADCP discharge-measurement system is the only choice for use at a particular measurement site. ADCP systems are not yet ?turnkey;? they are still under development, and for proper operation, require a significant amount of operator training. Not only must the operator have a rudimentary knowledge of acoustic physics, but also a working knowledge of ADCP operation, the manufacturer's discharge-measurement software, and boating techniques and safety.

  2. Measuring discharge with acoustic Doppler current profilers from a moving boat

    USGS Publications Warehouse

    Mueller, David S.; Wagner, Chad R.; Rehmel, Michael S.; Oberg, Kevin A.; Rainville, Francois

    2013-01-01

    The use of acoustic Doppler current profilers (ADCPs) from a moving boat is now a commonly used method for measuring streamflow. The technology and methods for making ADCP-based discharge measurements are different from the technology and methods used to make traditional discharge measurements with mechanical meters. Although the ADCP is a valuable tool for measuring streamflow, it is only accurate when used with appropriate techniques. This report presents guidance on the use of ADCPs for measuring streamflow; this guidance is based on the experience of U.S. Geological Survey employees and published reports, papers, and memorandums of the U.S. Geological Survey. The guidance is presented in a logical progression, from predeployment planning, to field data collection, and finally to post processing of the collected data. Acoustic Doppler technology and the instruments currently (2013) available also are discussed to highlight the advantages and limitations of the technology. More in-depth, technical explanations of how an ADCP measures streamflow and what to do when measuring in moving-bed conditions are presented in the appendixes. ADCP users need to know the proper procedures for measuring discharge from a moving boat and why those procedures are required, so that when the user encounters unusual field conditions, the procedures can be adapted without sacrificing the accuracy of the streamflow-measurement data.

  3. Measurements of current speed using an Aanderaa RCM4 current meter in the presence of surface waves

    NASA Astrophysics Data System (ADS)

    Sherwin, T. J.

    1988-02-01

    It is shown that the Aanderaa RCM4 with Savonius rotor integrates motions that have a period significantly smaller than the recording interval, thus causing a quantifiable amplification of the observed mean speed. The minimum speed that can be recorded is 2ν/;π, where ν is the amplitude of the speed of the oscillating motion. In general, the amplification factor decreases as the ratio of mean speed over ν increases. The theory appears to explain the difference in observations made by an Aanderaa RCM4 and a neighbouring EG&G VMCM when particle velocities due to swell are included. It is recommended that vector averaging current meters should be used for current measurement in the upper 50-100 m of shelf sea regions that experience small tidal currents and a large oceanic swell.

  4. Invariant currents in lossy acoustic waveguides with complete local symmetry

    NASA Astrophysics Data System (ADS)

    Kalozoumis, P. A.; Richoux, O.; Diakonos, F. K.; Theocharis, G.; Schmelcher, P.

    2015-07-01

    We implement the concept of complete local symmetry in lossy acoustic waveguides. Despite the presence of losses, the existence of a spatially invariant current is shown theoretically and observed experimentally. We demonstrate how this invariant current leads to the generalization of the Bloch and parity theorems for lossy systems defining a mapping of the pressure field between symmetry-related spatial domains. Using experimental data, we verify this mapping with remarkable accuracy. For the performed experiment, we employ a construction technique based on local symmetries that allows the design of setups with prescribed perfect transmission resonances in the lossless case. Our results reveal the fundamental role of symmetries in restricted spatial domains, and they clearly indicate that completely locally symmetric devices constitute a promising class of setups with regard to the manipulation of wave propagation.

  5. Evaluation of the Acoustic Doppler Velocity Meter for Computation of Discharge Records at Three Sites in Colorado, 2004-2005

    USGS Publications Warehouse

    Stevens, Michael R.; Diaz, Paul; Smits, Dennis E.

    2008-01-01

    The U.S. Geological Survey (USGS), in cooperation with the Colorado Water Conservation Board, conducted a study in 2004-2005 at three sites in Colorado: Bear Creek at Morrison, Clear Creek near Empire, and Redlands Canal near Grand Junction. The study was done to evaluate acoustic Doppler velocity meter (ADVM) technology in different hydrologic settings that are characteristic of many Colorado streamflow-gaging sites. ADVMs have been tested and used extensively in many parts of the United States by USGS but not in Colorado where relatively small, shallow, clear, coarse-bed streams that ice up in the winter may affect the ADVM suitability. In this study, ADVM instrumentation was successfully used and discharge computations compared favorably, generally within 5 to 10 percent, with conventional USGS stage/discharge methods at the three Colorado sites. However, two factors, encountered in this study, may adversely affect the use of ADVM technology in Colorado. First, for some streams, the depth required (about 1.5 feet for a side-looking instrument) cannot be met during low-flow periods of the year. Second, cold temperatures and freezing-thawing cycles can produce ice effects that could prevent collection of usable ADVM (and stage) data.

  6. Loch Linnhe `94: Current meter array operations and on-site analysis

    SciTech Connect

    Chambers, D.H.; Jones, H.E.

    1995-08-11

    This report documents the operation and on-site data analysis of the LLNL Current Meter Array (CMA) which was fielded at Loch Linnhe `94. The CMA is a large floating array of 10 sensors which measure horizontal current near the water surface. The measurements are used to interpret radar images of the water surface. This experiment was conducted as a part of the Joint UK/US Radar Ocean Imaging (ROI) Program. It was held at Loch Linnhe, Scotland in September 1994. The experiment consisted of measuring natural and ship-generated internal waves (IWs) in Loch Linnhe and imaging them with a land-based, dual frequency, dual-polarization real aperture radar operated by the UK. The goal was to determine the relationship between the amplitude of IWs as measured by instrumentation deployed in the water and the modulation they produce in radar images of the water surface.

  7. Validation of HF Radar ocean surface currents in the Ibiza Channel using lagrangian drifters, moored current meter and underwater gliders

    NASA Astrophysics Data System (ADS)

    Lana, Arancha; Fernández, Vicente; Orfila, Alejandro; Troupin, Charles; Tintoré, Joaquín

    2015-04-01

    SOCIB High Frequency (HF) radar is one component of a multi-platform system located in the Balearic Islands and made up of Lagrangian platforms (profilers and drifting buoys), fixed stations (sea-level, weather, mooring and coastal), beach monitoring (camera), gliders, a research vessel as well as an ocean forecast system (waves and hydrodynamics). The HF radar system overlooks the Ibiza Channel, known as a 'choke point" where Atlantic and Mediterranean water masses interact and where meridional exchanges of water mass properties between the Balearic and the Algerian sub-basins take place. In order to determine the reliability of surface velocity measurements in this area, a quality assessment of the HF Radar is essential. We present the results of several validation experiments performed in the Ibiza Channel in 2013 and 2014. Of particular interest is an experiment started in September 2014 when a set of 13 surface drifters with different shapes and drogue lengths were released in the area covered by the HF radar. The drifter trajectories can be examined following the SOCIB Deployment Application (DAPP): http://apps.socib.es/dapp. Additionally, a 1-year long time series of surface currents obtained from a moored surface current-meter located in the Ibiza Channel, inside the area covered by the HF radar, was also used as a useful complementary validation exercise. Direct comparison between both radial surface currents from each radar station and total derived velocities against drifters and moored current meter velocities provides an assessment of the HF radar data quality at different temporal periods and geographical areas. Statistics from these comparisons give good correlation and low root-mean-square deviation. The results will be discussed for different months, geographical areas and types of surface drifters and wind exposure. Moreover, autonomous underwater glider constitutes an additional source of information for the validation of the observed velocity

  8. Data Quality Control for Vessel Mounted Acoustic Doppler Current Profiler. Application for the Western Mediterranean Sea

    NASA Technical Reports Server (NTRS)

    Garcia-Gorriz, E.; Front, J.; Candela, J.

    1997-01-01

    A systematic Data Quality Checking Protocol for vessel Mounted Acoustic Doppler Current Profiler observations is proposed. Previous-to-acquisition conditions are considered along with simultaneous ones.

  9. Analysis of current-meter data at Columbia River gaging stations, Washington and Oregon

    USGS Publications Warehouse

    Savini, John; Bodhaine, G.L.

    1971-01-01

    The U.S. Geological Survey developed equipment to measure stream velocity simultaneously with 10 current meters arranged in a vertical and to measure velocity closer to the streambed than attainable with conventional equipment. With the 10 current meters, synchronous velocities were recorded for a period of 66 minutes at 10 different depths in one vertical of one gaging-station cross section. In addition, with a current meter installed on a special bracket to allow measurements to 0.5 foot above streambed, data were obtained at two to four verticals in four gaging-station cross sections. The mean velocity determined for the 66-minute period of record was 3.30 fps (feet per second). The graphic record of velocity was analyzed on a minute-by-minute basis. It was noted that the shape of the vertical velocity curves (plot of horizontal flow velocities measured in a vertical) changed from one minute to the next, but the change seemed to be random. Velocities obtained at different depths in the, profile fluctuated significantly, with the 1-minute velocities obtained at 0.05 depth (5 percent of total depths measured from the surface at indicated vertical) showing the smallest range--0.66 fps--and those at 0.55 depth the largest range--l.22 fps. The standard deviation, expressed in feet per second, of the velocity at each point in the vertical tended to increase with depth--from 0.16 fps at 0.05 depth to a maximum of 0.24 fps at 0.75 depth. The standard deviation, expressed as a percentage of the mean velocity, ranged from about 4 percent near the surface to 11 percent at 0.95 depth. In spite of the fluctuation in mean velocity that occurred during the 66 minutes and observation period of 4 minutes yields a mean velocity that differs from the 66-minute mean by less than one-half of a percent. Determining the mean velocity by averaging the 10-point observations of the 66minute run proved to be as accurate as by plotting the vertical velocity curvy (from the averaged 10

  10. Half-year-long measurements with a buoy-mounted acoustic Doppler current profiler in the Somali Current

    NASA Astrophysics Data System (ADS)

    Schott, Friedrich; Johns, William

    1987-05-01

    A self-contained, upward-looking acoustic Doppler current profiler (ADCP), mounted in the top float of a subsurface mooring was deployed in the Somali Current at 2°14'N, 45°55'E from September 17, 1985, to April 25, 1986. The instrument operated at a frequency of 150 kHz, with a vertical beam angle of 20°. Vector-averaged profiles of horizontal and vertical velocity were recorded every 4 hours, using 200 pings per ensemble at a vertical bin length of 8.7 m. The mooring was deployed in very rough topography, settling in a trough at 337 m depth with the ADCP located at 267 m depth. Data retrieval over the entire recording period was complete, with Doppler biasing from side lobe reception of vertically traveling rays affecting only the top 20 m below the surface. Over the 7-month deployment the instrument recorded current profiles encompassing the end of the 1985 summer monsoon and entire winter monsoon and also through the spring transition into the early onset phase of the 1986 summer monsoon. Significant echo amplitude variations of week-to-month-long duration were observed, which were only partially related to horizontal flow variations associated with the monsoons. Projection of the strong horizontal currents (exceeding 150 cm/s at times) into the vertical component was not observed, attesting to fairly exact orientation of the four beams and tilt meters. This indicates that the vertical current measurement from ADCPs can be potentially useful for phenomena with vertical velocities exceeding a few millimeters per second. However, an analysis of echo amplitude and vertical current variations at the diurnal period suggests that the measured vertical velocity is, at least at that period, probably dominated by active vertical migration of biological scatterers through the water column.

  11. Acoustic Doppler current profiler applications used in rivers and estuaries by the U.S. Geological Survey

    USGS Publications Warehouse

    Gotvald, Anthony J.; Oberg, Kevin A.

    2009-01-01

    The U.S. Geological Survey (USGS) has collected streamflow information for the Nation's streams since 1889. Streamflow information is used to predict floods, manage and allocate water resources, design engineering structures, compute water-quality loads, and operate water-control structures. The current (2007) size of the USGS streamgaging network is over 7,400 streamgages nationwide. The USGS has progressively improved the streamgaging program by incorporating new technologies and techniques that streamline data collection while increasing the quality of the streamflow data that are collected. The single greatest change in streamflow measurement technology during the last 100 years has been the development and application of high frequency acoustic instruments for measuring streamflow. One such instrument, the acoustic Doppler current profiler (ADCP), is rapidly replacing traditional mechanical current meters for streamflow measurement (Muste and others, 2007). For more information on how an ADCP works see Simpson (2001) or visit http://hydroacoustics.usgs.gov/. The USGS has used ADCPs attached to manned or tethered boats since the mid-1990s to measure streamflow in a wide variety of conditions (fig. 1). Recent analyses have shown that ADCP streamflow measurements can be made with similar or greater accuracy, efficiency, and resolution than measurements made using conventional current-meter methods (Oberg and Mueller, 2007). ADCPs also have the ability to measure streamflow in streams where traditional current-meter measurements previously were very difficult or costly to obtain, such as streams affected by backwater or tides. In addition to streamflow measurements, the USGS also uses ADCPs for other hydrologic measurements and applications, such as computing continuous records of streamflow for tidally or backwater affected streams, measuring velocity fields with high spatial and temporal resolution, and estimating suspended-sediment concentrations. An overview

  12. Comparison of index velocity measurements made with a horizontal acoustic Doppler current profiler

    USGS Publications Warehouse

    Jackson, P. Ryan; Johnson, Kevin K.; Duncker, James J.

    2012-01-01

    The State of Illinois' annual withdrawal from Lake Michigan is limited by a U.S. Supreme Court decree, and the U.S. Geological Survey (USGS) is responsible for monitoring flows in the Chicago Sanitary and Ship Canal (CSSC) near Lemont, Illinois as a part of the Lake Michigan Diversion Accounting overseen by the U.S. Army Corps of Engineers, Chicago District. Every 5 years, a technical review committee consisting of practicing engineers and academics is convened to review the U.S. Geological Survey's streamgage practices in the CSSC near Lemont, Illinois. The sixth technical review committee raised a number of questions concerning the flows and streamgage practices in the CSSC near Lemont and this report provides answers to many of those questions. In addition, it is the purpose of this report to examine the index velocity meters in use at Lemont and determine whether the acoustic velocity meter (AVM), which is now the primary index velocity meter, can be replaced by the horizontal acoustic Doppler current profiler (H-ADCP), which is currently the backup meter. Application of the AVM and H-ADCP to index velocity measurements in the CSSC near Lemont, Illinois, has produced good ratings to date. The site is well suited to index velocity measurements in spite of the large range of velocities and highly unsteady flows at the site. Flow variability arises from a range of sources: operation of the waterway through control structures, lockage-generated disturbances, commercial and recreational traffic, industrial withdrawals and discharges, natural inflows, seiches, and storm events. The influences of these factors on the index velocity measurements at Lemont is examined in detail in this report. Results of detailed data comparisons and flow analyses show that use of bank-mounted instrumentation such as the AVM and H-ADCP appears to be the best option for index velocity measurement in the CSSC near Lemont. Comparison of the rating curves for the AVM and H-ADCP demonstrates

  13. Evaluation of wet-line depth-correction methods for cable-suspended current meters

    USGS Publications Warehouse

    Coon, W.F.; Futrell, James C.

    1986-01-01

    Wet-line depth corrections for cable-suspended current meter and weight not perpendicular to the water surface have been evaluated using cable-suspended weights towed by a boat in still water. A fathometer was used to track a Columbus sounding weight and to record its actual depth for several apparent depths, weight sizes, and towed velocities. Cable strumming, tension, and weight veer are noted. Results of this study suggest possible differences between observed depth corrections and corrections obtained from the wet-line correction table currently in use. These differences may have resulted from test conditions which deviated from the inherent assumptions of the wet-line table: (1) drag on the weight in the sounding position at the bottom of a stream can be neglected; and (2) the distribution of horizontal drag on the sounding line is in accordance with the variation of velocity with depth. Observed depth corrections were compared to wet-line table values used for determining the 0.8-depth position of the sounding weight under these conditions; the results indicate that questionable differences exist. (Lantz-PTT)

  14. Acoustic Doppler Current Profiler Data Processing System manual [ADCP

    USGS Publications Warehouse

    Cote, Jessica M.; Hotchkiss, Frances S.; Martini, Marinna; Denham, Charles R.; revisions by Ramsey, Andree L.; Ruane, Stephen

    2000-01-01

    This open-file report describes the data processing software currently in use by the U.S. Geological Survey (USGS), Woods Hole Coastal and Marine Science Center (WHCMSC), to process time series of acoustic Doppler current data obtained by Teledyne RD Instruments Workhorse model ADCPs. The Sediment Transport Instrumentation Group (STG) at the WHCMSC has a long-standing commitment to providing scientists high quality oceanographic data published in a timely manner. To meet this commitment, STG has created this software to aid personnel in processing and reviewing data as well as evaluating hardware for signs of instrument malfunction. The output data format for the data is network Common Data Form (netCDF), which meets USGS publication standards. Typically, ADCP data are recorded in beam coordinates. This conforms to the USGS philosophy to post-process rather than internally process data. By preserving the original data quality indicators as well as the initial data set, data can be evaluated and reprocessed for different types of analyses. Beam coordinate data are desirable for internal and surface wave experiments, for example. All the code in this software package is intended to run using the MATLAB program available from The Mathworks, Inc. As such, it is platform independent and can be adapted by the USGS and others for specialized experiments with non-standard requirements. The software is continuously being updated and revised as improvements are required. The most recent revision may be downloaded from: http://woodshole.er.usgs.gov/operations/stg/Pubs/ADCPtools/adcp_index.htm The USGS makes this software available at the user?s discretion and responsibility.

  15. Feasibility study of the use of the acoustic velocity meter for measurement of net outflow from the Sacramento-San Joaquin Delta in California

    USGS Publications Warehouse

    Smith, Winchell

    1969-01-01

    A reliable measure of the fresh-water outflow from the Sacramento-San Joaquin delta is needed for the operation of the California Water Project and for the evaluation of the interrelated water problems of the delta and San Francisco Bay regions. The Chipps Island channel, immediately downstream from the confluence of the Sacramento and San Joaquin Rivers, is the most promising site for this flow measurement, but the conventional techniques used for evaluating steady flows cannot be employed there because the channel reach is in the tidal zone, and reversals of flow occur during each tidal cycle. Net outflows, which may be as little-as 2,000 cubic feet per second must necessarily be computed as the difference between the large ebbflow and floodflow volumes that move back and forth between the delta region and San Francisco Bay. Discharges during peak periods of the ebb and flood tidal cycles may exceed 300,000 cubic feet per second. In consequence, a very high degree of precision must be maintained in the gross flow measurements if meaningful computations of net outflow are to be made. This report evaluates the probable accuracies that might be achieved by use of an AVM (acoustic velocity meter), a device which measures the stream velocity along a diagonal line across the channel. The study indicates that this line velocity will provide a stable index of the mean velocity in the channel and that such an index could be used as a primary parameter for the computation of discharge. Therefore, net outflows probably could be computed with the required accuracy by the use of such a device. The significant factors controlling the precision of measurement would be the stability of the channel geometry and streamline orientation, the precision with which the current-meter measurements needed for calibration of the system could be made, the instrumental calibration stability of the AVM system, and the length of period over which net outflows were computed. The AVM system

  16. Discharge-measurement system using an acoustic Doppler current profiler with applications to large rivers and estuaries

    USGS Publications Warehouse

    Simpson, Michael R.; Oltmann, Richard N.

    1993-01-01

    Discharge measurement of large rivers and estuaries is difficult, time consuming, and sometimes dangerous. Frequently, discharge measurements cannot be made in tide-affected rivers and estuaries using conventional discharge-measurement techniques because of dynamic discharge conditions. The acoustic Doppler discharge-measurement system (ADDMS) was developed by the U.S. Geological Survey using a vessel-mounted acoustic Doppler current profiler coupled with specialized computer software to measure horizontal water velocity at 1-meter vertical intervals in the water column. The system computes discharge from water-and vessel-velocity data supplied by the ADDMS using vector-algebra algorithms included in the discharge-measurement software. With this system, a discharge measurement can be obtained by engaging the computer software and traversing a river or estuary from bank to bank; discharge in parts of the river or estuarine cross sections that cannot be measured because of ADDMS depth limitations are estimated by the system. Comparisons of ADDMS-measured discharges with ultrasonic-velocity-meter-measured discharges, along with error-analysis data, have confirmed that discharges provided by the ADDMS are at least as accurate as those produced using conventional methods. In addition, the advantage of a much shorter measurement time (2 minutes using the ADDMS compared with 1 hour or longer using conventional methods) has enabled use of the ADDMS for several applications where conventional discharge methods could not have been used with the required accuracy because of dynamic discharge conditions.

  17. THE VERTICAL PLANAR MOTION MECHANISM; A DYNAMIC TEST APPARATUS FOR EVALUATING CURRENT METERS AND OTHER MARINE INSTRUMENTATION

    EPA Science Inventory

    The overall objective was to provide a dynamic test apparatus that can produce known, controlled high frequency dynamics for the evaluation of current meters and other marine instrumentation. Of primary interest is the establishment of flow sensor measurement capabilities, and he...

  18. Acoustic and aerodynamic performance of a 1.83-meter (6-ft) diameter 1.25-pressure-ratio fan (QF-8)

    NASA Technical Reports Server (NTRS)

    Woodward, R. P.; Lucas, J. G.

    1976-01-01

    A 1.25-pressure-ratio 1.83-meter (6-ft) tip diameter experimental fan stage with characteristics suitable for engine application on STOL aircraft was tested for acoustic and aerodynamic performance. The design incorporated proven features for low noise, including absence of inlet guide vanes, low rotor blade tip speed, low aerodynamic blade loading, and long axial spacing between the rotor and stator blade rows. The fan was operated with five exhaust nozzle areas. The stage noise levels generally increased with a decrease in nozzle area. Separation of the acoustic one-third octave results into broadband and pure-tone components showed the broadband noise to be greater than the corresponding pure-tone components. The sideline perceived noise was highest in the rear quadrants. The acoustic results of QF-8 were compared with those of two similar STOL application fans in the test series. The QF-8 had somewhat higher relative noise levels than those of the other two fans. The aerodynamic results of QF-8 and the other two fans were compared with corresponding results from 50.8-cm (20-in.) diam scale models of these fans and design values. Although the results for the full-scale and scale models of the other two fans were in reasonable agreement for each design, the full-scale fan QF-8 results showed poor performance compared with corresponding model results and design expectations. Facility effects of the full-scale fan QF-8 installation were considered in analyzing this discrepancy.

  19. Electromagnetic Flow Meter Having a Driver Circuit Including a Current Transducer

    NASA Technical Reports Server (NTRS)

    Karon, David M. (Inventor); Cushing, Vincent (Inventor); Patel, Sandeep K. (Inventor)

    2014-01-01

    An electromagnetic flow meter (EMFM) accurately measures both the complete flow rate and the dynamically fluctuating flow rate of a fluid by applying a unipolar DC voltage to excitation coils for a predetermined period of time, measuring the electric potential at a pair of electrodes, determining a complete flow rate and independently measuring the dynamic flow rate during the "on" cycle of the DC excitation, and correcting the measurements for errors resulting from galvanic drift and other effects on the electric potential. The EMFM can also correct for effects from the excitation circuit induced during operation of the EMFM.

  20. A modified beam-to-earth transformation to measure short-wavelength internal waves with an acoustic Doppler current profiler

    USGS Publications Warehouse

    Scotti, A.; Butman, B.; Beardsley, R.C.; Alexander, P.S.; Anderson, S.

    2005-01-01

    The algorithm used to transform velocity signals from beam coordinates to earth coordinates in an acoustic Doppler current profiler (ADCP) relies on the assumption that the currents are uniform over the horizontal distance separating the beams. This condition may be violated by (nonlinear) internal waves, which can have wavelengths as small as 100-200 m. In this case, the standard algorithm combines velocities measured at different phases of a wave and produces horizontal velocities that increasingly differ from true velocities with distance from the ADCP. Observations made in Massachusetts Bay show that currents measured with a bottom-mounted upward-looking ADCP during periods when short-wavelength internal waves are present differ significantly from currents measured by point current meters, except very close to the instrument. These periods are flagged with high error velocities by the standard ADCP algorithm. In this paper measurements from the four spatially diverging beams and the backscatter intensity signal are used to calculate the propagation direction and celerity of the internal waves. Once this information is known, a modified beam-to-earth transformation that combines appropriately lagged beam measurements can be used to obtain current estimates in earth coordinates that compare well with pointwise measurements. ?? 2005 American Meteorological Society.

  1. Saturation diving with heliox to 350 meters. Observation on hearing threshold, brainstem evoked response and acoustic impedance.

    PubMed

    Wang, L; Jiang, W; Gong, J H; Zheng, X Y

    1994-12-01

    Four divers were compressed to 350 m to observe changes in hearing threshold, brainstem evoked response and acoustic impedance. The divers experienced no tinnitus, impairment of hearing, earache during compression. Examination showed that the threshold of lower frequency range of hearing was elevated because of the masking effect of the noise in the hyperbaric chamber. Changes in waveform and latency of brainstem evoked response were due to changes in sound wave transmission affected by the chamber pressure and a poor ratio of signal to noise in the hyperbaric environment with heliox. All these changes were transient. After leaving the chamber, the hearing threshold and brainstem evoked response returned to normal. Besides, there were no changes in tympanogram, acoustic compliance and stapedius reflex before and after diving. This indicated the designed speed of compression and decompression in the experiment caused no damage to the divers' acoustic system, and the functions of their Eustachain tubes, middle and inner ears were normal during the diving test. PMID:7882734

  2. Filamentation instability of nonextensive current-driven plasma in the ion acoustic frequency range

    SciTech Connect

    Khorashadizadeh, S. M. Rastbood, E.; Niknam, A. R.

    2014-12-15

    The filamentation and ion acoustic instabilities of nonextensive current-driven plasma in the ion acoustic frequency range have been studied using the Lorentz transformation formulas. Based on the kinetic theory, the possibility of filamentation instability and its growth rate as well as the ion acoustic instability have been investigated. The results of the research show that the possibility and growth rate of these instabilities are significantly dependent on the electron nonextensive parameter and drift velocity. Besides, the increase of electrons nonextensive parameter and drift velocity lead to the increase of the growth rates of both instabilities. In addition, the wavelength region in which the filamentation instability occurs is more stretched in the presence of higher values of drift velocity and nonextensive parameter. Finally, the results of filamentation and ion acoustic instabilities have been compared and the conditions for filamentation instability to be dominant mode of instability have been presented.

  3. Modeling and managing urban water demand through smart meters: Benefits and challenges from current research and emerging trends

    NASA Astrophysics Data System (ADS)

    Cominola, A.; Giuliani, M.; Castelletti, A.; Piga, D.; Rizzoli, A. E.

    2015-12-01

    Urban population growth, climate and land use change are expected to boost residential water demand in urban contexts in the next decades. In such a context, developing suitable demand-side management strategies is essential to meet future water demands, pursue water savings, and reduce the costs for water utilities. Yet, the effectiveness of water demand management strategies (WDMS) relies on our understanding of water consumers' behavior, their consumption habits, and the water use drivers. While low spatial and temporal resolution water consumption data, as traditionally gathered for billing purposes, hardly support this understanding, the advent of high-resolution, smart metering technologies allowed for quasi real-time monitoring water consumption at the single household level. This, in turn, is advancing our ability in characterizing consumers' behavior, modeling, and designing user-oriented residential water demand management strategies. Several water smart metering programs have been rolled-out in the last two decades worldwide, addressing one or more of the following water demand management phases: (i) data gathering, (ii) water end-uses characterization, (iii) user modeling, (iv) design and implementation of personalized WDMS. Moreover, the number of research studies in this domain is quickly increasing and big economic investments are currently being devoted worldwide to smart metering programs. With this work, we contribute the first comprehensive review of more than 100 experiences in the field of residential water demand modeling and management, and we propose a general framework for their classification. We revise consolidated practices, identify emerging trends and highlight the challenges and opportunities for future developments given by the use of smart meters advancing residential water demand management. Our analysis of the status quo of smart urban water demand management research and market constitutes a structured collection of information

  4. The high speed buffer board: A SAIL EIA-485 communications accelerator card for the vector measuring current meter

    NASA Astrophysics Data System (ADS)

    Singer, Robin; Butler, Douglas M.

    1990-07-01

    A High Speed Buffer Board (HSBB) was developed for the Vector Measuring Current Meter (VMCM) to implement the transmission of data at 9600 baud over an EIA-485 link. The HSBB significantly extends the VMCM communication functionality, which was previously limited to 300 baud transmission via 20mA current loop or FSK telemetry. The increased speed allows rapid sampling of a large number of current meters on a common cable and the EIA-485 circuitry, which was designed for low power operation, provides a useful multipoint communication method for data transmission over long cable lengths. SAIL protocol (IEEE 997) was utilized to coordinate data transfer by the instruments on a common link. An MC68HC11 microcontroller resides in the VMCM, buffering data it receives at 300 baud from the VMCM UART. In response to a jumper selectable SAIL address, the MC68HC11 offloads the data 9600 baud via EIA-485 to the SAIL controller. Synchronous data collection from many instruments is ensured by the SAIL synoptic set command and an embedded resynchronization/reset command. The low power consumption allows deployments of six months or more with a standard VMCM battery stack.

  5. Acoustics

    NASA Astrophysics Data System (ADS)

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

  6. Acoustic microfluidics: Capillary waves and vortex currents in a spherical fluid drop

    NASA Astrophysics Data System (ADS)

    Lebedev-Stepanov, P. V.; Rudenko, O. V.

    2016-07-01

    We calculate the radiation forces in a spherical drop lying on a solid substrate. The forces form as a result of the action of a capillary wave on a fluid as it propagates along the free spherical surface. We study the structure of acoustic currents excited by the radiation forces.

  7. Acoustic performance of two 1.83-meter-diameter fans designed for a wind-tunnel drive system

    NASA Technical Reports Server (NTRS)

    Soderman, P. R.; Page, V. R.

    1977-01-01

    A parametric study was made of the noise generated by two 1.83-m (6-ft) diameter fans operating up to a maximum pressure ratio of 1.03. One fan had 15 rotor blades, 23 stator blades, and a maximum rotational speed of 1200 rpm. The other fan had 9 rotor blades, 13 stator blades, and a maximum speed of 2,000 rpm. The fans were approximately 1/7-scale models of the 12.2-m (40-ft) diameter fans proposed for repowering the NASA-Ames 40- by 80 foot wind tunnel. The fans were operated individually in a 23.8-m (78-ft) long duct. Sound pressure levels in the duct were used to determine radiated acoustic power as fan speed, blade angle, and mass flow were varied. Results show that the low speed fan was slightly quieter than the high speed fan and, when scaled to full scale, would be 16 db quieter than the present wind tunnel fans. The fan noise varied directly with thrust regardless of whether thrust was varied by rotational speed or blade setting for the ranges studied.

  8. Description and evaluation of the Acoustic Profiling of Ocean Currents (APOC) system used on R. V. Oceanus cruise 96 on 11-22 May 1981

    NASA Technical Reports Server (NTRS)

    Joyce, T. M.; Rintoul, S. R., Jr.; Barbour, R. L.

    1982-01-01

    The underway current profiling system which consists of a microprocessor controlled data logger that collects and formats data from a four beam Ametek-Straza 300 kHz acoustic Doppler current profiler, heading from the ship's gyrocompass, and navigation information from a Loran-C receiver and a satellite navigation unit is discussed. Data are recorded on magnetic tape and real time is calculated. Time averaging is required to remove effects of ship motion. An intercomparison is made with a moored vector measuring current meter (VMCM). The mean difference in hourly averaged APOC and VMCM currents over the four hour intercomparison is a few mm s minus including: two Gulf Stream crossings, a warm core ring survey, and shallow water in a frontal zone to the east of Nantucket Shoals.

  9. The average direct current offset values for small digital audio recorders in an acoustically consistent environment.

    PubMed

    Koenig, Bruce E; Lacey, Douglas S

    2014-07-01

    In this research project, nine small digital audio recorders were tested using five sets of 30-min recordings at all available recording modes, with consistent audio material, identical source and microphone locations, and identical acoustic environments. The averaged direct current (DC) offset values and standard deviations were measured for 30-sec and 1-, 2-, 3-, 6-, 10-, 15-, and 30-min segments. The research found an inverse association between segment lengths and the standard deviation values and that lengths beyond 30 min may not meaningfully reduce the standard deviation values. This research supports previous studies indicating that measured averaged DC offsets should only be used for exclusionary purposes in authenticity analyses and exhibit consistent values when the general acoustic environment and microphone/recorder configurations were held constant. Measured average DC offset values from exemplar recorders may not be directly comparable to those of submitted digital audio recordings without exactly duplicating the acoustic environment and microphone/recorder configurations. PMID:24502252

  10. Test Results for a 25 Meter Prototype Fault Current Limiting Hts Cable for Project Hydra

    NASA Astrophysics Data System (ADS)

    Rey, C. M.; Duckworth, R. C.; Demko, J. A.; Ellis, A.; James, D. R.; Gouge, M. J.; Tuncer, E.

    2010-04-01

    The Oak Ridge National Laboratory (ORNL) has tested a 25-m long prototype High Temperature Superconducting (HTS) cable with inherent Fault-Current Limiting (FCL) capability at its HTS cable test facility. The HTS-FCL cable and terminations were designed and fabricated by Ultera, which is a joint venture between Southwire and nkt cables. System integration and HTS wire were provided by American Superconductor Corporation who was the overall team leader of the project. The ultimate goal of the 25-m HTS-FCL cable test program was to verify the design and ensure the operational integrity for the eventual installation of a ˜200-m fully functional HTS-FCL cable in the Consolidated Edison electric grid located in downtown New York City. The 25-m HTS-FCL cable consisted of a three-phase (3-Φ) HTS Triax™ design with a cold dielectric between the phases. The HTS-FCL cable had an operational voltage of 13.8 kV phase-to-phase (7967 V phase-to-ground) and an operating current of 4000 Arms per phase, which is the highest operating current to date of any HTS cable. The 25-m HTS-FCL cable was subjected to a series of cryogenic and electrical tests. Test results from the 25-m HTS-FCL cable are presented and discussed.

  11. Observations of near-inertial waves in acoustic Doppler current profiler measurements made during the Mixed Layer Dynamics Experiment

    NASA Astrophysics Data System (ADS)

    Chereskin, T. K.; Levine, M. D.; Harding, A. J.; Regier, L. A.

    1989-06-01

    Measurements of upper ocean shear made during the Mixed Layer Dynamics Experiment (MILDEX) provide evidence of large horizontal scale motion at near-inertial frequency. The measurements consist of shipboard acoustic Doppler current profiles. Four large-scale spatial surveys of 2-4 days duration were made by the R/V Wecoma as a set of boxes approximately 60 km per side around a drifting current meter buoy. Velocity time series from the drifting buoy and from sonar measurements made from FLIP also indicated the presence of motions at near-inertial frequency. Horizontal length and time scales of the motion are estimated from the phase of the shear vector measured during the spatial surveys. Estimates of the length scale of the waves range from 500 to 1000 km, and the frequency is approximately 1.1f. The behavior of the phase is found to be consistent with a model of narrow-band inertial waves with vertical structure such that there is a zero crossing in velocity at the base of the mixed layer (40-60 m).

  12. Acoustics

    NASA Technical Reports Server (NTRS)

    Goodman, Jerry R.; Grosveld, Ferdinand

    2007-01-01

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

  13. Eddy Current Minimizing Flow Plug for Use in Flow Conditioning and Flow Metering

    NASA Technical Reports Server (NTRS)

    England, John Dwight (Inventor); Kelley, Anthony R. (Inventor)

    2015-01-01

    An eddy-current-minimizing flow plug has open flow channels formed between the plug's inlet and outlet. Each open flow channel includes (i) a first portion that originates at the inlet face and converges to a location within the plug that is downstream of the inlet, and (ii) a second portion that originates within the plug and diverges to the outlet. The diverging second portion is approximately twice the length of the converging first portion. The plug is devoid of planar surface regions at its inlet and outlet, and in fluid flow planes of the plug that are perpendicular to the given direction of a fluid flowing therethrough.

  14. Baroclinic tidal generation in the Kauai Channel inferred from high-frequency radio Doppler current meters

    NASA Astrophysics Data System (ADS)

    Zaron, Edward D.; Chavanne, Cedric; Egbert, Gary D.; Flament, Pierre

    2009-10-01

    A data-assimilating three-dimensional primitive equations model is used in conjunction with high-frequency radio Doppler current data to infer tidal conversion during two 3-month periods in Kauai Channel, Hawaii. It is estimated that the M barotropic tide loses energy at rates of 1.1 and 1.2 GW during these periods, values 25% lower than predicted with the prior model. Of this total conversion rate, approximately 85% exits the model domain to enter the deep ocean as a coherent propagating internal tide. Although the inferred tidal currents differ in detail during the 3-month periods, the domain-averaged tidal energetics do not. The tidal solutions obtained by the data-assimilative model do not exactly satisfy the primitive equations dynamics since a residual forcing is permitted in the horizontal momentum and mass conservation equations. An analysis of these residuals indicates that they are consistent with the expected amplitude of tidal-mesoscale interactions; however, the residual forcing in the mass equation, which represents refraction by the mesoscale buoyancy field, is much too small. An attempt to reconcile the forcing residuals with known processes suggests, by elimination, that tidal-mesoscale interactions are of leading-order significance and should be included in future analysis of baroclinic tidal energy budgets.

  15. Comparison, analysis, and estimation of discharge data from two acoustic velocity meters on the Chicago Sanitary and Ship Canal at Romeoville, Illinois

    USGS Publications Warehouse

    Melching, Charles S.; Oberg, Kevin A.

    1993-01-01

    The acoustic velocity meter (AVM) on the Chicago Sanitary and Ship Canal (the Canal) at Romeoville, Ill., provides vital information for the accounting of the diversion of water from Lake Michigan. A detailed analysis of the discharge record on the Canal at Romeoville was done by the U.S. Geological Survey to establish the most accurate estimates of discharge for water years 1986-91. The analysis involved (1) checking the consistency of the discharges estimated by two different AVM's installed at Romeoville for consecutive time periods by statistical and regression analyses, (2) adjusting the discharge record to account for corrections to the width and depth of the Canal determined by field measurements, and (3) development of equations for estimating discharge on days when the AVM was inoperative using discharge estimates made by the Metropolitan Water Reclamation District of Greater Chicago at the lock, powerhouse, and controlling works at Lockport, Ill. No signi- ficant difference in the discharge estimates made by the two AVM's could be documented. The estimation equations combined regression analysis with physical principles of the outlet-works operation. The estimation equations simulated the verification period of October 1, 1991, to May 31, 1992, within 0.22, 5.15, and 0.66 percent for the mean, standard deviation, and skewness coefficient, respectively. Discharges were recalculated for the corrected width and depth, estimated for the periods of AVM inoperation, and entered into the discharge record for the station.

  16. Eddy Current Minimizing Flow Plug for Use in Flow Conditioning and Flow Metering

    NASA Technical Reports Server (NTRS)

    England, John Dwight (Inventor); Kelley, Anthony R. (Inventor)

    2015-01-01

    An eddy-current-minimizing flow plug has an outer radial wall with open flow channels formed between the plug's inlet and outlet. The plug has a central region coupled to the inner surface of the outer radial wall. Each open flow channel includes (i) a first portion originating at the inlet and converging to a location in the plug where convergence is contributed to by changes in thickness of the outer radial wall and divergence of the central region, and (ii) a second portion originating in the plug and diverging to the outlet where divergence is contributed to by changes in thickness of the outer radial wall and convergence of the central region. For at least a portion of the open flow channels, a central axis passing through the first and second portions is non-parallel with respect to the given direction of the flow.

  17. High-resolution velocimetry in energetic tidal currents using a convergent-beam acoustic Doppler profiler

    SciTech Connect

    Sellar, Brian; Harding, Samuel F.; Richmond, Marshall C.

    2015-07-16

    An array of convergent acoustic Doppler velocimeters has been developed and tested for the high resolution measurement of three-dimensional tidal flow velocities in an energetic tidal site. This configuration has been developed to increase spatial resolution of velocity measurements in comparison to conventional acoustic Doppler profilers (ADPs) which characteristically use diverging acoustic beams emanating from a single instrument. This is achieved using converging acoustic beams with a sample volume at the focal point of 0.03 m3. The array is also able to simultaneously measure three-dimensional velocity components in a profile throughout the water column, and as such is referred to herein as a converging-beam acoustic Doppler profiler (CADP). Mid-depth profiling is achieved through integration of the sensor platform with the operational Alstom 1MW DeepGen-IV Tidal Turbine. This proof-of-concept paper outlines system configuration and comparison to measurements provided by co-installed reference instrumentation. Comparison of CADP to standard ADP velocity measurements reveals a mean difference of 8 mm/s, standard deviation of 18 mm/s, and order-of-magnitude reduction in realizable length-scale. CADP focal point measurements compared to a proximal single-beam reference show peak cross-correlation coefficient of 0.96 over 4.0 s averaging period and a 47% reduction in Doppler noise. The dual functionality of the CADP as a profiling instrument with a high resolution focal point make this configuration a unique and valuable advancement in underwater velocimetry enabling improved turbulence, resource and structural loading quantification and validation of numerical simulations. Alternative modes of operation have been implemented including noise-reducing bi-static sampling. Since waves are simultaneously measured it is expected that derivatives of this system will be a powerful tool in wave-current interaction studies.

  18. Monitoring suspended sediment transport in an ice-affected river using acoustic Doppler current profilers

    NASA Astrophysics Data System (ADS)

    Moore, S. A.; Ghareh Aghaji Zare, S.; Rennie, C. D.; Ahmari, H.; Seidou, O.

    2013-12-01

    Quantifying sediment budgets and understanding the processes which control fluvial sediment transport is paramount to monitoring river geomorphology and ecological habitat. In regions that are subject to freezing there is the added complexity of ice. River ice processes impact flow distribution, water stage and sediment transport. Ice processes typically have the largest impact on sediment transport and channel morphodynamics when ice jams occur during ice cover formation and breakup. Ice jams may restrict flow and cause local acceleration when released. Additionally, ice can mechanically scour river bed and banks. Under-ice sediment transport measurements are lacking due to obvious safety and logistical reasons, in addition to a lack of adequate measurement techniques. Since some rivers can be covered in ice during six months of the year, the lack of data in winter months leads to large uncertainty in annual sediment load calculations. To address this problem, acoustic profilers are being used to monitor flow velocity, suspended sediment and ice processes in the Lower Nelson River, Manitoba, Canada. Acoustic profilers are ideal for under-ice sediment flux measurements since they can be operated autonomously and continuously, they do not disturb the flow in the zone of measurement and acoustic backscatter can be related to sediment size and concentration. In March 2012 two upward-facing profilers (1200 kHz acoustic Doppler current profiler, 546 KHz acoustic backscatter profiler) were installed through a hole in the ice on the Nelson River, 50 km downstream of the Limestone Generating Station. Data were recorded for four months, including both stable cover and breakup periods. This paper presents suspended sediment fluxes calculated from the acoustic measurements. Velocity data were used to infer the vertical distribution of sediment sizes and concentrations; this information was then used in the interpretation of the backscattered intensity data. It was found that

  19. Characterization of Retrogression and Re-Aging Heat Treatment of AA7075-T6 Using Nonlinear Acoustics and Eddy Current

    SciTech Connect

    Ananthula, Rajeshwar; Ko, Ray T.; Sathish, Shamachary; Blodgett, Mark

    2004-02-26

    Nonlinear acoustic parameter and eddy current methods have been utilized to characterize the heat treatment process of retrogression and re-aging of aluminum 7075-T6. The results of nonlinear acoustic parameter measurements show two distinct peaks at 30 minutes and 45 minutes of retrogression time. The phase of the through-thickness eddy current signal shows a minimum at 42 minutes of retrogression time. Application of combined methods for identifying the optimized properties in the material is discussed.

  20. Acoustic Doppler discharge-measurement system

    USGS Publications Warehouse

    Simpson, Michael R.; Oltmann, Richard N.

    1990-01-01

    A discharge-measurement system that uses a vessel-mounted acoustic Doppler current profiler has been developed and tested by the U.S. Geological Survey. Discharge measurements using the system require a fraction of the time needed for conventional current-meter discharge measurements and do not require shore-based navigational aids or tag lines for positioning the vessel.

  1. Current-driven dust ion-acoustic instability in a collisional dusty plasma

    SciTech Connect

    Merlino, R.L.

    1997-02-01

    A fluid analysis of the excitation of dust ion-acoustic (DIA) waves in a collisional dusty plasma is presented. The DIA waves are excited by a relative drift of the electrons and ions produced by a steady-state electric field applied to the plasma. The DIA instability is more easily excited if the relative concentration of negatively charged dust is increased. The current interest in dusty plasmas is due to the realization of their importance in various astrophysical and geophysical environments (e.g., interstellar space, comet tails, planetary ring systems, and the polar mesosphere) as well as in industrial plasma processing devices used in semiconductor manufacturing.

  2. Quality assurance plan for discharge measurements using broadband acoustic Doppler current profilers

    USGS Publications Warehouse

    Lipscomb, S.W.

    1995-01-01

    The recent introduction of the Acoustic Doppler Current Profiler (ADCP) as an instrument for measuring velocities and discharge in the riverine and estuarine environment promises to revolutionize the way these data are collected by the U.S. Geological Survey. The ADCP and associated software, however, compose a complex system and should be used only by qualifies personnel. Standard procedures should be rigorously followed to ensure that the quality of data collected is commensurate with the standards set by the Water Resources Division for all its varied activities in hydrologic investigations.

  3. Comparison of Acoustic Energy Meter (AEM) and Schmidt hammer 'R' for rapid assessment of rock surface hardness: a preliminary assessment from southeast Queensland, Australia

    NASA Astrophysics Data System (ADS)

    Brook, Martin; Winkler, Stefan

    2015-04-01

    This research focuses on one of the key challenges in geomorphology - quantifying rock surface hardness via in situ measurements, to provide information on rock physical properties. This has been a focus in recent years with the rapid emergence of studies that center on surface and near surface weathering impacts, and rates of material loss. Indeed, a key element to understanding how weathering and erosion processes combine to influence rock surface (and landscape) evolution is the measurement and monitoring of rock surface hardness. We provide results from a preliminary assessment of the applicability of the Acoustic Energy Meter (AEM) to subaerial rock surface hardness, in comparison with an N-Type Schmidt hammer. The AEM apparatus consists of a geophone which is in contact with the rock surface and some electronics. The AEM is held normal to the surface to be tested and the surface is struck with a small hammer (typically 0.75 kg), with the AEM quantifying the decay time of seismically-induced oscillations within the top c. 1-2 m of the rock mass. Previous work using an AEM has focused on measuring roof stability and delamination in South African underground coal, gold and platinum mines, where long AEM reverberation times correlated well with weak rock mass and dense microfracturing. However, the technique has rarely been applied to the assessment of rock surfaces in a subaerial setting. We applied the technique to a range of lithologies at five sites in southeast Queensland in the Brisbane area, each an exposure of phyllite, granite, mudstone, argillite or volcanic tuff. The aims were: (1) quantifying the response of different rock masses to the AEM technique; and (2) assessing the applicability of the AEM as a rapid in situ measure of rock hardness by comparing results with Schmidt hammer 'R' values from the same exposures. Results showed that the AEM is useful in discriminating rock hardness across rocks with different lithological properties. Second, an

  4. High-resolution velocimetry in energetic tidal currents using a convergent-beam acoustic Doppler profiler

    NASA Astrophysics Data System (ADS)

    Sellar, Brian; Harding, Samuel; Richmond, Marshall

    2015-08-01

    An array of single-beam acoustic Doppler profilers has been developed for the high resolution measurement of three-dimensional tidal flow velocities and subsequently tested in an energetic tidal site. This configuration has been developed to increase spatial resolution of velocity measurements in comparison to conventional acoustic Doppler profilers (ADPs) which characteristically use divergent acoustic beams emanating from a single instrument. This is achieved using geometrically convergent acoustic beams creating a sample volume at the focal point of 0.03 m3. Away from the focal point, the array is also able to simultaneously reconstruct three-dimensional velocity components in a profile throughout the water column, and is referred to herein as a convergent-beam acoustic Doppler profiler (C-ADP). Mid-depth profiling is achieved through integration of the sensor platform with the operational commercial-scale Alstom 1 MW DeepGen-IV Tidal Turbine deployed at the European Marine Energy Center, Orkney Isles, UK. This proof-of-concept paper outlines the C-ADP system configuration and comparison to measurements provided by co-installed reference instrumentation. Comparison of C-ADP to standard divergent ADP (D-ADP) velocity measurements reveals a mean difference of 8 mm s-1, standard deviation of 18 mm s-1, and an order of magnitude reduction in realisable length scale. C-ADP focal point measurements compared to a proximal single-beam reference show peak cross-correlation coefficient of 0.96 over 4.0 s averaging period and a 47% reduction in Doppler noise. The dual functionality of the C-ADP as a profiling instrument with a high resolution focal point make this configuration a unique and valuable advancement in underwater velocimetry enabling improved quantification of flow turbulence. Since waves are simultaneously measured via profiled velocities, pressure measurements and surface detection, it is expected that derivatives of this system will be a powerful tool in

  5. Validation of HF radar probing of the vertical shear of surface currents by acoustic Doppler current profiler measurements

    NASA Astrophysics Data System (ADS)

    Ivonin, Dmitry V.; Broche, Pierre; Devenon, Jean-Luc; Shrira, Victor I.

    2004-04-01

    There exists no practical way of measuring vertical shear in the water just below the air/sea interface that contains information on air/water momentum fluxes. The paper is concerned with the validation of a recently proposed method of remote sensing of sea subsurface shear by means of a commonly used single-frequency HF radar based on the use of the second-order Bragg echo. To this end a dedicated field experiment was carried out off the French Mediterranean coast. In parallel with the HF radar probing, the independent simultaneous measurements of the subsurface shear profile were obtained by means of acoustic Doppler current profiler mounted on a floating platform, whose position was monitored by GPS. The comparison shows a fairly good agreement of the results (the discrepancy does not exceed 15%) and suggests a higher accuracy of the HF probing.

  6. Plugging meter

    DOEpatents

    Nagai, Akinori

    1979-01-01

    A plugging meter for automatically measuring the impurity concentration in a liquid metal is designed to have parallel passages including a cooling passage provided with a plugging orifice and with a flow meter, and a by-pass passage connected in series to a main passage having another flow meter, so that the plugging points may be obtained from the outputs of both flow meters. The plugging meter has a program signal generator, a flow-rate ratio setter and a comparator, and is adapted to change the temperature of the plugging orifice in accordance with a predetermined pattern or gradient, by means of a signal representative of the temperature of plugging orifice and a flow-rate ratio signal obtained from the outputs of both flow meters. This plugging meter affords an automatic and accurate measurement of a multi-plugging phenomenon taking place at the plugging orifice.

  7. Variance of discharge estimates sampled using acoustic Doppler current profilers from moving boats

    USGS Publications Warehouse

    Garcia, Carlos M.; Tarrab, Leticia; Oberg, Kevin; Szupiany, Ricardo; Cantero, Mariano I.

    2012-01-01

    This paper presents a model for quantifying the random errors (i.e., variance) of acoustic Doppler current profiler (ADCP) discharge measurements from moving boats for different sampling times. The model focuses on the random processes in the sampled flow field and has been developed using statistical methods currently available for uncertainty analysis of velocity time series. Analysis of field data collected using ADCP from moving boats from three natural rivers of varying sizes and flow conditions shows that, even though the estimate of the integral time scale of the actual turbulent flow field is larger than the sampling interval, the integral time scale of the sampled flow field is on the order of the sampling interval. Thus, an equation for computing the variance error in discharge measurements associated with different sampling times, assuming uncorrelated flow fields is appropriate. The approach is used to help define optimal sampling strategies by choosing the exposure time required for ADCPs to accurately measure flow discharge.

  8. Averaged indicators of secondary flow in repeated acoustic Doppler current profiler crossings of bends

    USGS Publications Warehouse

    Dinehart, R.L.; Burau, J.R.

    2005-01-01

    [1] Cross-stream velocity was measured in a large river bend at high spatial resolution over three separate survey episodes. A suite of methods for resolving cross-stream velocity distributions was tested on data collected using acoustic Doppler current profilers (ADCP) in the sand-bedded Sacramento River, California. The bend was surveyed with repeated ADCP crossings at eight cross sections during a rising limb of high discharge in February 2004 and twice on recession in March 2004. By translating and interpolating repeated ADCP crossings to planar grids, velocity ensembles at similar positions along irregular boat paths could be averaged. The averaging minimized turbulent fluctuations in streamwise velocities over 1 m/s, enabling the resolution of weaker cross-stream velocities (???15-30 cm/s). Secondary-flow influence on suspended sediment was inferred from a lateral region of acoustic backscatter intensity aligned with outward flow over the point bar. A near-bed decrease in backscatter intensity across the pool corresponded with inward cross-stream flow. These suspension indicators were used to orient averaged velocity grids for unambiguously defining the cross-stream velocity magnitudes. Additional field investigations could test whether the correlation between cross-stream velocity and backscatter intensity patterns results from helical recirculation of suspended sediment to the inside of the bend. These river measurements, consistent with classic and recent laboratory studies, show that ADCP surveys can provide refined views of secondary flow and sediment movement in large rivers.

  9. Estimating suspended solids concentrations from backscatter intensity measured by acoustic Doppler current profiler in San Francisco Bay, California

    USGS Publications Warehouse

    Gartner, J.W.

    2004-01-01

    The estimation of mass concentration of suspended solids is one of the properties needed to understand the characteristics of sediment transport in bays and estuaries. However, useful measurements or estimates of this property are often problematic when employing the usual methods of determination from collected water samples or optical sensors. Analysis of water samples tends to undersample the highly variable character of suspended solids, and optical sensors often become useless from biological fouling in highly productive regions. Acoustic sensors, such as acoustic Doppler current profilers that are now routinely used to measure water velocity, have been shown to hold promise as a means of quantitatively estimating suspended solids from acoustic backscatter intensity, a parameter used in velocity measurement. To further evaluate application of this technique using commercially available instruments, profiles of suspended solids concentrations are estimated from acoustic backscatter intensity recorded by 1200- and 2400-kHz broadband acoustic Doppler current profilers located at two sites in San Francisco Bay, California. ADCP backscatter intensity is calibrated using optical backscatterance data from an instrument located at a depth close to the ADCP transducers. In addition to losses from spherical spreading and water absorption, calculations of acoustic transmission losses account for attenuation from suspended sediment and correction for nonspherical spreading in the near field of the acoustic transducer. Acoustic estimates of suspended solids consisting of cohesive and noncohesive sediments are found to agree within about 8-10% (of the total range of concentration) to those values estimated by a second optical backscatterance sensor located at a depth further from the ADCP transducers. The success of this approach using commercially available Doppler profilers provides promise that this technique might be appropriate and useful under certain conditions in

  10. Use of an Acoustic Doppler Current Profiler (ADCP) to Measure Hypersaline Bidirectional Discharge

    USGS Publications Warehouse

    Johnson, K.K.; Loving, B.L.

    2002-01-01

    The U.S. Geological Survey measures the exchange of flow between the north and south parts of Great Salt Lake, Utah, as part of a monitoring program. Turbidity and bidirectional flow through the breach in the causeway that divides the lake into two parts makes it difficult to measure discharge with conventional streamflow techniques. An acoustic Doppler current profiler (ADCP) can be used to more accurately define the angles of flow and the location of the interface between the layers of flow. Because of the high salinity levels measured in Great Salt Lake (60-280 parts per thousand), special methods had to be developed to adjust ADCP-computed discharges for the increased speed of sound in hypersaline waters and for water entrained at the interface between flow layers.

  11. A GIS-based Computational Tool for Multidimensional Flow Velocity by Acoustic Doppler Current Profilers

    NASA Astrophysics Data System (ADS)

    Kim, D.; Winkler, M.; Muste, M.

    2015-06-01

    Acoustic Doppler Current Profilers (ADCPs) provide efficient and reliable flow measurements compared to other tools for characteristics of the riverine environments. In addition to originally targeted discharge measurements, ADCPs are increasingly utilized to assess river flow characteristics. The newly developed VMS (Velocity Mapping Software) aims at providing an efficient process for quality assurance, mapping velocity vectors for visualization and facilitating comparison with physical and numerical model results. VMS was designed to provide efficient and smooth work flows for processing groups of transects. The software allows the user to select group of files and subsequently to conduct statistical and graphical quality assurance on the files as a group or individually as appropriate. VMS also enables spatial averaging in horizontal and vertical plane for ADCP data in a single or multiple transects over the same or consecutive cross sections. The analysis results are displayed in numerical and graphical formats.

  12. [Development of ultrasonic power meter].

    PubMed

    Huang, Hongxin; Hu, Changming; Zheng, Yan; Xu, Honglei; Zhou, Wohua; Wu, Ziwen; Yu, Liudan; Hao, Jiandong; Luo, Yifan

    2014-07-01

    This article describes the design and development of an ultrasonic power meter which is consist of an electronic balance, a practice target, an acoustic enclosures and a blocking. The electronic balance mounted on the blocking is linked with the practice target by connecting rod. By adjusting the blocking makes the practice target suspended above ultrasound probe, and then the ultrasonic power can be measured. After initial tests, the ultrasonic power meter performanced with good stability and high precision. PMID:25330604

  13. Turbulent Fluxes of Suspended Sediment from Coupled Acoustic Doppler Current Profilers

    NASA Astrophysics Data System (ADS)

    Hoitink, T.; Sassi, M.; Vermeulen, B.

    2014-12-01

    Turbulent diffusion is a cornerstone in geophysical fluid mechanics, controlling the exchange of momentum, heat and mass in surface flows occurring in the atmosphere, in rivers and in the ocean. In fluvial and coastal systems, modeling turbulent diffusion of momentum and suspended sediment requires knowledge about turbulent diffusivities, which is generally derived from parameterizations based on laboratory experiments. Field determinations of momentum and sediment diffusivities are cumbersome, requiring an instrumental array to simultaneously sample turbulence and mean flow quantities in time and in space. Recently, a new technique to analyze geophysical surface flow turbulence was introduced, appropriate for large scale systems, based on coupling of acoustic Doppler current profilers (ADCPs). Here, we extend this approach to obtain collocated profiles of both the Reynolds stress tensor and eddy covariance fluxes, to derive vertical profiles of turbulent momentum and sediment diffusivity in a tidal river. Shear and normal stresses are obtained by combining the variances in radial velocities measured by the ADCP beams. The covariances between radial velocities and calibrated acoustic backscatter allow to determine the three Cartesian components of the turbulent flux of suspended sediment. The main advantage of this new approach is that flow velocity and sediment concentration measurements are exactly collocated, and that it allows to profile over longer ranges, in comparison to existing techniques. Results show that vertical profiles of the inverse turbulent Prandtl-Schmidt number is coherent with corresponding profiles of the sediment diffusivity, rather than with profiles of the eddy viscosity. This implies modelling suspended sediment dynamics requires knowledge about the sediment diffusivity, as the Prandtl-Schmidt number cannot be estimated from the eddy viscosity alone.

  14. DC attenuation meter

    DOEpatents

    Hargrove, Douglas L.

    2004-09-14

    A portable, hand-held meter used to measure direct current (DC) attenuation in low impedance electrical signal cables and signal attenuators. A DC voltage is applied to the signal input of the cable and feedback to the control circuit through the signal cable and attenuators. The control circuit adjusts the applied voltage to the cable until the feedback voltage equals the reference voltage. The "units" of applied voltage required at the cable input is the system attenuation value of the cable and attenuators, which makes this meter unique. The meter may be used to calibrate data signal cables, attenuators, and cable-attenuator assemblies.

  15. The upper-ocean response to typhoons as measured at a moored acoustic Doppler current profiler

    NASA Astrophysics Data System (ADS)

    Liu, Ze; Hou, Yijun; Xie, Qiang; Hu, Po; Liu, Yahao

    2015-09-01

    A moored acoustic Doppler current profiler (ADCP) data, satellite-derived sea surface wind data, and the chlorophyll- a concentration were used to examine the influence of typhoon events on the upper ocean in the central Luzon Strait. The data were collected between August 27 and October 6, 2011. Large changes in ocean dynamics and marine life were recorded in the upper layers over the short term during the transit of each of the three violent typhoons that passed over the region during the study period. The geostrophic flow during the period of ADCP monitoring was comparable to the Ekman flow, recently shown to be prominent in the upper layer. Based on the influence of the three typhoon events that swept the Luzon Strait or traversed Luzon Island on their way to the South China Sea, we postulated a typhoon-induced upwelling around the ADCP and found that upward isothermal displacements reached 11.8-39.0 m, which was confirmed by the sea-level anomaly data recorded at the same time. This variability in the upper ocean may play an important role in biological activity, especially in offshore deep-sea regions.

  16. Long-term acoustic measurement of temperature variations in the Pacific North Equatorial Current

    NASA Astrophysics Data System (ADS)

    Kaneko, Arata; Zheng, Hong; Nakano, Iwao; Yuan, Gang; Fujimori, Hidetoshi; Yoneyama, Kunio

    1996-07-01

    A 247-km path length sound transmission experiment using a single sound source sending to a remote receiver was performed during February-June 1992 along the latitudinal line of 10°N in the North Equatorial Current off Mindanao Island, Phillipines. The range-averaged temperature was reconstructed at three layers (65-500 m, 500-1500 m, and 1500-3300 m) through the inverse analysis of travel time data obtained between the source and receiver. The temperature remained nearly constant during February-March and increased by 0.8°C for the upper and middle layers and 0.2°C for the lower layer in the subsequent months. A 0.8°C temperature increase was in good agreement with expendable bathythermograph results obtained at the start and finish of the experiment. National Oceanic and Atmospheric Administration advanced very high resolution radiometer images also show evidence of a warming of the surface water by 2.0°C during the same period. It is concluded that this acoustic experiment observed a warm event which took place in the western equatorial Pacific with the decay of the 1991-1992 El Niño.

  17. Aquatic Habitat Mapping with an Acoustic Doppler Current Profiler: Considerations for Data Quality

    USGS Publications Warehouse

    Gaeuman, David; Jacobson, Robert B.

    2005-01-01

    When mounted on a boat or other moving platform, acoustic Doppler current profilers (ADCPs) can be used to map a wide range of ecologically significant phenomena, including measures of fluid shear, turbulence, vorticity, and near-bed sediment transport. However, the instrument movement necessary for mapping applications can generate significant errors, many of which have not been inadequately described. This report focuses on the mechanisms by which moving-platform errors are generated, and quantifies their magnitudes under typical habitat-mapping conditions. The potential for velocity errors caused by mis-alignment of the instrument?s internal compass are widely recognized, but has not previously been quantified for moving instruments. Numerical analyses show that even relatively minor compass mis-alignments can produce significant velocity errors, depending on the ratio of absolute instrument velocity to the target velocity and on the relative directions of instrument and target motion. A maximum absolute instrument velocity of about 1 m/s is recommended for most mapping applications. Lower velocities are appropriate when making bed velocity measurements, an emerging application that makes use of ADCP bottom-tracking to measure the velocity of sediment particles at the bed. The mechanisms by which heterogeneities in the flow velocity field generate horizontal velocities errors are also quantified, and some basic limitations in the effectiveness of standard error-detection criteria for identifying these errors are described. Bed velocity measurements may be particularly vulnerable to errors caused by spatial variability in the sediment transport field.

  18. Correcting acoustic Doppler current profiler discharge measurements biased by sediment transport

    USGS Publications Warehouse

    Mueller, D.S.; Wagner, C.R.

    2007-01-01

    A negative bias in discharge measurements made with an acoustic Doppler current profiler (ADCP) is attributed to the movement of sediment on or near the streambed, and is an issue widely acknowledged by the scientific community. The integration of a differentially corrected global positioning system (DGPS) to track the movement of the ADCP can be used to avoid the systematic bias associated with a moving bed. DGPS, however, cannot provide consistently accurate positions because of multipath errors and satellite signal reception problems on waterways with dense tree canopy along the banks, in deep valleys or canyons, and near bridges. An alternative method of correcting for the moving-bed bias, based on the closure error resulting from a two-way crossing of the river, is presented. The uncertainty in the mean moving-bed velocity measured by the loop method is shown to be approximately 0.6cm/s. For the 13 field measurements presented, the loop method resulted in corrected discharges that were within 5% of discharges measured utilizing DGPS to compensate for moving-bed conditions. ?? 2007 ASCE.

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

    SciTech Connect

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

    2015-01-12

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

  20. Solar Meter

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The instrument pictured is an inexpensive solar meter which is finding wide acceptance among architects, engineers and others engaged in construction of solar energy facilities. It detects the amount of solar energy available at a building site, information necessary to design the most efficient type of solar system for a particular location. Incorporating technology developed by NASA's Lewis Research Center, the device is based upon the solar cell, which provides power for spacecraft by converting the sun's energy to electricity. The meter is produced by Dodge Products, Inc., Houston, Texas, a company formed to bring the technology to the commercial marketplace.

  1. A Preliminary Evaluation of Near-Transducer Velocities Collected with Low-Blank Acoustic Doppler Current Profiler

    USGS Publications Warehouse

    Gartner, J.W.; Ganju, N.K.

    2002-01-01

    Many streams and rivers for which the US Geological Survey must provide discharge measurements are too shallow to apply existing acoustic Doppler current profiler techniques for flow measurements of satisfactory quality. Because the same transducer is used for both transmitting and receiving acoustic signals in most Doppler current profilers, some small time delay is required for acoustic "ringing" to be damped out of transducers before meaningful measurements can be made. The result of that time delay is that velocity measurements cannot be made close to the transducer thus limiting the usefulness of these instruments in shallow regions. Manufacturers and users are constantly striving for improvements to acoustic instruments which would permit useful discharge measurements in shallow rivers and streams that are still often measured with techniques and instruments more than a century old. One promising area of advance appeared to be reduction of time delay (blank) required between transmitting and receiving signals during acoustic velocity measurements. Development of a low- or zero-blank transducer by RD Instruments3 held promise that velocity measurements could be made much closer to the transducer and thus in much shallower water. Initial experience indicates that this is not the case; limitation of measurement quality appears to be related to the physical presence of the transducer itself within the flow field. The limitation may be the result of changes to water flow pattern close to the transducer rather than transducer ringing characteristics as a function of blanking distance. Results of field experiments are discussed that support this conclusion and some minimum measurement distances from transducer are suggested based on water current speed and ADCP sample modes.

  2. Saturation meter

    DOEpatents

    Gregurech, S.

    1984-08-01

    A saturation meter for use in a pressurized water reactor plant comprising a differential pressure transducer having a first and second pressure sensing means and an alarm. The alarm is connected to the transducer and is preset to activate at a level of saturation prior to the formation of a steam void in the reactor vessel.

  3. Acoustic Noise Alters Selective Attention Processes as Indicated by Direct Current (DC) Brain Potential Changes

    PubMed Central

    Trimmel, Karin; Schätzer, Julia; Trimmel, Michael

    2014-01-01

    Acoustic environmental noise, even of low to moderate intensity, is known to adversely affect information processing in animals and humans via attention mechanisms. In particular, facilitation and inhibition of information processing are basic functions of selective attention. Such mechanisms can be investigated by analyzing brain potentials under conditions of externally directed attention (intake of environmental information) versus internally directed attention (rejection of environmental stimuli and focusing on memory/planning processes). This study investigated brain direct current (DC) potential shifts—which are discussed to represent different states of cortical activation—of tasks that require intake and rejection of environmental information under noise. It was hypothesized that without background noise rejection tasks would show more positive DC potential changes compared to intake tasks and that under noise both kinds of tasks would show positive DC shifts as an expression of cortical inhibition caused by noise. DC potential shifts during intake and rejection tasks were analyzed at 16 standard locations in 45 persons during irrelevant speech or white noise vs. control condition. Without noise, rejection tasks were associated with more positive DC potential changes compared to intake tasks. During background noise, however, this difference disappeared and both kinds of tasks led to positive DC shifts. Results suggest—besides some limitations—that noise modulates selective attention mechanisms by switching to an environmental information processing and noise rejection mode, which could represent a suggested “attention shift”. Implications for fMRI studies as well as for public health in learning and performance environments including susceptible persons are discussed. PMID:25264675

  4. Capacitance Meter

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Anders Precision Instrument Co.'s original meter could not measure dissipation leakage in capacitors. Seeking to add that capability, the company planned an advanced model. Before starting work, company president, Thomas Anderson, sought technical assistance from NASA's NERAC (New England Research Application Center). Anderson wanted a survey of the status and capabilities of NASA's electronic measuring devices. NERAC performed a search of six databases, including NASA's and provided a comprehensive report on state of the art worldwide.

  5. Advanced Metering Infrastructure

    SciTech Connect

    2007-10-15

    The report provides an overview of the development of Advanced Metering Infrastructure (AMI). Metering has historically served as the cash register for the utility industry. It measured the amount of energy used and supported the billing of customers for that usage. However, utilities are starting to look at meters in a whole different way, viewing them as the point of contact with customers in supporting a number of operational imperatives. The combination of smart meters and advanced communications has opened up a variety of methods for utilities to reduce operating costs while offering new services to customers. A concise look is given at what's driving interest in AMI, the components of AMI, and the creation of a business case for AMI. Topics covered include: an overview of AMI including the history of metering and development of smart meters; a description of the key technologies involved in AMI; a description of key government initiatives to support AMI; an evaluation of the current market position of AMI; an analysis of business case development for AMI; and, profiles of 21 key AMI vendors.

  6. Current state of acoustic wave propagation modelling and its use in the estimation of impact on marine mammals

    NASA Astrophysics Data System (ADS)

    Racca, R.; Hannay, D.; Carr, S.

    2006-05-01

    Underwater acoustic wave propagation modelling has matured into a sophisticated and reliable forecasting tool for predicting the acoustic noise footprints of geophysical exploration activities. Computational methods such as Parabolic Equation solutions of the wave function can account for all aspects of acoustic propagation including diffraction, mode stripping, and compressional and shear wave transmission in the seabed substrate. Given sufficient knowledge of the acousto-physical properties of the water column and the seabed, it is possible to estimate the acoustic transmission loss for individual sound frequencies and hence the overall attenuation of a spectrally described source at any range. In combination with numerical models that provide reliable estimates of the acoustic pulse properties and spatial pattern of the sound emission from any design of airgun array, wave propagation modelling provides the means to fully characterize the ensonification of an area without need for experimental measurement, allowing the potential impact on the marine environment of a planned operation to be studied in advance of physical deployment of the equipment. In this presentation we provide an overview of the current state of acoustic propagation modelling methods with particular emphasis on full noise footprint estimation, whereby the acoustic propagation model is automatically run along multiple traverses to cover the region of interest to a desired spatial resolution. The prediction of sound level footprints, however, is only a step in the process of estimating the acoustic impact on sea life and especially marine mammals. The interaction between the sound and the subject is also influenced by the subject's frequency-dependent auditory sensitivity relative to the frequency content of the sounds to which it is exposed. Much experimental work has been performed recently to measure frequency- dependent auditory thresholds (audiograms) for many marine mammal species. The

  7. A novel flattop current regulated energy discharge type pulsed power supply and magnet yielding 4. 4 kGauss-meter for 6 milliseconds

    SciTech Connect

    Visser, A.T.

    1989-07-01

    Most energy discharge power supplies obtain their bursts of power from the energy stored in charged capacitors when it is suddenly released into a load. This note describes the design of a similar small 800 Joules energy discharge type power supply and magnet. The magnet gap is 2 in.{times}2 in.{times}25-1/2 in. long and produces about 4.4 kGauss-meters at a rate of 12 pulses per minute. Each pulse is current regulated at the top for a duration of 6 msec. and varies less than 0.6% of set value. Current regulation at flattop is obtained by switching a resistor in and out of the discharge circuit with an IGBT at a rate of about 5 kHz. Most energy discharge systems produce half sine wave pulses, and current regulation is obtained by controlling the charge voltage at the energy storage capacitor, resulting only in a controlled peak current value of the half sine wave pulse. The current value at the top changes substantially during 6 msec. depending on the operating frequency.

  8. Evaluation of Acoustic Doppler Current Profiler to Measure Discharge at New York Power Authority's Niagara Power Project, Niagara Falls, New York

    USGS Publications Warehouse

    Zajd, Henry J., Jr.

    2007-01-01

    The need for accurate real-time discharge in the International Niagara River hydro power system requires reliable, accurate and reproducible data. The U.S. Geological Survey has been widely using Acoustic Doppler Current Profilers (ADCP) to accurately measure discharge in riverine channels since the mid-1990s. The use of the ADCP to measure discharge has remained largely untested at hydroelectric-generation facilities such as the New York Power Authority's (NYPA) Niagara Power Project in Niagara Falls, N.Y. This facility has a large, engineered diversion channel with the capacity of high volume discharges in excess of 100,000 cubic feet per second (ft3/s). Facilities such as this could benefit from the use of an ADCP, if the ADCP discharge measurements prove to be more time effective and accurate than those obtained from the flow-calculation techniques that are currently used. Measurements of diversion flow by an ADCP in the 'Pant Leg' diversion channel at the Niagara Power Project were made on November 6, 7, and 8, 2006, and compared favorably (within 1 percent) with those obtained concurrently by a conventional Price-AA current-meter measurement during one of the ADCP measurement sessions. The mean discharge recorded during each 2-hour individual ADCP measurement session compared favorably with (3.5 to 6.8 percent greater than) the discharge values computed by the flow-calculation method presently in use by NYPA. The use of ADCP technology to measure discharge could ultimately permit increased power-generation efficiency at the NYPA Niagara Falls Power Project by providing improved predictions of the amount of water (and thus the power output) available.

  9. Inference of tidal elevation in shallow water using a vessel-towed acoustic Doppler current profiler

    NASA Astrophysics Data System (ADS)

    Li, Chunyan; Valle-Levinson, Arnoldo; Atkinson, Larry P.; Royer, Tom C.

    2000-11-01

    Vessel-towed acoustic Doppler current profilers (ADCPs) have been widely used to measure velocity profiles. Since the instrument is usually mounted on a catamaran floating on the surface, previous studies have used the water surface as the reference level from which the vertical coordinate for the velocity profile is defined. However, because of the tidal oscillation, the vertical coordinate thus defined is time-dependent in an Earth-coordinate system, which introduces an error to the estimated harmonic constants for the velocity. As a result, the total transport will also be in error. This is particularly a problem in shallow waters where the tidal elevation is relatively large. Therefore tidal elevation needs to be resolved to make a correct harmonic analysis for the velocity. The present study is aimed at resolving the tidal elevation change in shallow water using a vessel-towed ADCP. Semidiurnal and diurnal tidal elevations across the lower Chesapeake Bay have been determined using a vessel-towed ADCP. Data from four cruises ranging from 25 to 92 hours in 1996 and 1997 are used. Water depth averaged every 30 s by the ADCP is studied by harmonic and statistical analysis. By selecting only the data within a narrow band (˜320 m) over the planned transect, we are able to improve the reliability of the data. We then grid the depth data along the 16 km transect into 200 equal segments and use harmonic analysis to resolve the semidiurnal and diurnal tidal variations within each segment. We find that (1) the depth data from the ADCP contain both semidiurnal and diurnal signals that can be resolved, from which the surface elevation can be inferred, (2) the major error appears to come from spatial variation of the depth, (3) the semidiurnal and diurnal tidal variations of elevation inferred over flat bottom topography account for almost 100% of the total variability, while those measurements over large bottom slopes account for a much lower percentage of the total

  10. Acoustic Doppler current profiling from the JGOFS Arabian Sea cruises aboard the RV T.G. Thompson

    SciTech Connect

    Kim, H.S.; Flagg, C.N.; Shi, Y.

    1996-12-01

    Acoustic Doppler current profiler (ADCP) data is part of the core data for the US JGOFS Arabian Sea project, along with hydrographic and nutrient data. Seventeen cruises are scheduled to take place between September 1994 and January 1996 on the R/V T.G. Thompson. Seven of the cruises follow a standard cruise track, taking hydrographic, chemical and biological measurements. The rest of the cruises, which take place generally within the standard cruise region defined by a set track, are for the deployment and recovery of moored equipment and towing of a SeaSoar. Detailed description of ADCP hardware, the AutoADCP data acquisition system, and the collection of navigation and compass data on the Thompson is documented in Section 2. Followed by data collection for each cruise together with a cruise track, Section 3 presents the processing and analysis of velocity and acoustic backscatter intensity data. Section 5 shows results of profile quality diagnosis.

  11. Acoustic and aerodynamic performance of a variable-pitch 1.83-meter-(6-ft) diameter 1.20-pressure-ratio fan stage (QF-9)

    NASA Technical Reports Server (NTRS)

    Glaser, F. W.; Woodward, R. P.; Lucas, J. G.

    1977-01-01

    Far field noise data and related aerodynamic performance are presented for a variable pitch fan stage having characteristics suitable for low noise, STOL engine application. However, no acoustic suppression material was used in the flow passages. The fan was externally driven by an electric motor. Tests were made at several forward thrust rotor blade pitch angles and one for reverse thrust. Fan speed was varied from 60 to 120 percent of takeoff (design) speed, and exhaust nozzles having areas 92 to 105 percent of design were tested. The fan noise level was at a minimum at the design rotor blade pitch angles of 64 deg for takeoff thrust and at 57 deg for approach (50 percent takeoff thrust). Perceived noise along a 152.4-m sideline reached 100.1 PNdb for the takeoff (design) configuration for a stage pressure ratio of 1.17 and thrust of 57,600 N. For reverse thrust the PNL values were 4 to 5 PNdb above the takeoff values at comparable fan speeds.

  12. Acoustics Critical Readiness Review

    NASA Technical Reports Server (NTRS)

    Ballard, Kenny

    2010-01-01

    This presentation reviews the status of the acoustic equipment from the medical operations perspective. Included is information about the acoustic dosimeters, sound level meter, and headphones that are planned for use while on orbit. Finally there is information about on-orbit hearing assessments.

  13. Acoustic Doppler Current Profiler Measurements in the Tailrace at John Day Dam

    SciTech Connect

    Cook, Chris B.; Dibrani, Berhon; Serkowski, John A.; Richmond, Marshall C.; Titzler, P. Scott; Dennis, Gary W.

    2006-01-30

    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

  14. Impact of recirculation on the East Greenland Current in Fram Strait: Results from moored current meter measurements between 1997 and 2009

    NASA Astrophysics Data System (ADS)

    de Steur, L.; Hansen, E.; Mauritzen, C.; Beszczynska-Möller, A.; Fahrbach, E.

    2014-10-01

    Transports of total volume and water masses obtained from a mooring array in the East Greenland Current (EGC) in Fram Strait are presented for the period 1997-2009. The array in the EGC was moved along isobaths from 79°N to 78°50‧N in 2002 to line up with moorings in the eastern Fram Strait. Analysis of the time series at the two latitudes shows that associated with the southward move, the annual mean volume transport of the EGC increased from 5.8±1.8 Sv to 8.7±2.5 Sv, mostly related with an increase in barotropic flow. This suggests a recirculation of close to 3 Sv at 78°50‧N as a consequence of the large-scale wind-driven cyclonic gyre in the Nordic Seas. In addition, the volume transport at 78°50‧N showed a clear seasonal cycle which was absent at 79°N. Estimates of the wind-driven Sverdrup transport at two different latitudes show that the difference in total volume transport and seasonality can largely be explained by the wind-stress curl. However, weak transport in 2003 was only partially related with weak Sverdrup transport and coincided also with anomalously weak northerly winds. The stronger recirculation at 78°50‧N has also consequences for the observed Atlantic Water: there is significantly more Atlantic derived water present at the southerly latitude. In addition, the warm anomaly in Fram Strait between 2005 and 2007 doubled the amount of Recirculated Atlantic Water temporarily. Finally, we estimate that close to 2.7 Sv, or 50%, of Atlantic derived water recirculates in Fram Strait.

  15. Intelligent utility meter system

    SciTech Connect

    Frew, L.H.; Fuller, M.L.

    1989-02-07

    An intelligent utility meter system installation is described for measuring A.C. electric energy having repetitive A.C. cycles, comprising: (1) an ''outside'' principal meter unit including: (a) means for sampling current and voltage and for calculating power consumption at least 300 times per second; the sampling occurring asynchronously and not in any fixed time relationship with respect to the A.C. electricity cycles; (b) the outside unit further including means for determining the total kilowatt hours used, and the present billing status; and (c) alphanumeric display means for displaying power being used, total kilowatt hours and present billing status; (2) a remote ''inside'' unit including: (a) alphanumeric means for displaying the information displayed by the ''outside'' unit; (b) means for selectively retaining a desired continuously updated display; and (c) means for reading a credit card and automatically changing the billing status information within the intelligent utility meter as credit card information is read; and (3) the system including means for determining both the magnitude and direction of the electric power passing through the meter system.

  16. International Space Station Acoustics - A Status Report

    NASA Technical Reports Server (NTRS)

    Allen, Christopher S.; Denham, Samuel A.

    2011-01-01

    It is important to control acoustic noise aboard the International Space Station (ISS) to provide a satisfactory environment for voice communications, crew productivity, and restful sleep, and to minimize the risk for temporary and permanent hearing loss. Acoustic monitoring is an important part of the noise control process on ISS, providing critical data for trend analysis, noise exposure analysis, validation of acoustic analysis and predictions, and to provide strong evidence for ensuring crew health and safety, thus allowing Flight Certification. To this purpose, sound level meter (SLM) measurements and acoustic noise dosimetry are routinely performed. And since the primary noise sources on ISS include the environmental control and life support system (fans and airflow) and active thermal control system (pumps and water flow), acoustic monitoring will indicate changes in hardware noise emissions that may indicate system degradation or performance issues. This paper provides the current acoustic levels in the ISS modules and sleep stations, and is an update to the status presented in 20031. Many new modules, and sleep stations have been added to the ISS since that time. In addition, noise mitigation efforts have reduced noise levels in some areas. As a result, the acoustic levels on the ISS have improved.

  17. International Space Station Acoustics - A Status Report

    NASA Technical Reports Server (NTRS)

    Allen, Christopher S.

    2015-01-01

    It is important to control acoustic noise aboard the International Space Station (ISS) to provide a satisfactory environment for voice communications, crew productivity, alarm audibility, and restful sleep, and to minimize the risk for temporary and permanent hearing loss. Acoustic monitoring is an important part of the noise control process on ISS, providing critical data for trend analysis, noise exposure analysis, validation of acoustic analyses and predictions, and to provide strong evidence for ensuring crew health and safety, thus allowing Flight Certification. To this purpose, sound level meter (SLM) measurements and acoustic noise dosimetry are routinely performed. And since the primary noise sources on ISS include the environmental control and life support system (fans and airflow) and active thermal control system (pumps and water flow), acoustic monitoring will reveal changes in hardware noise emissions that may indicate system degradation or performance issues. This paper provides the current acoustic levels in the ISS modules and sleep stations and is an update to the status presented in 2011. Since this last status report, many payloads (science experiment hardware) have been added and a significant number of quiet ventilation fans have replaced noisier fans in the Russian Segment. Also, noise mitigation efforts are planned to reduce the noise levels of the T2 treadmill and levels in Node 3, in general. As a result, the acoustic levels on the ISS continue to improve.

  18. Volcanic Lightning, Pyroclastic Density Currents, Ballistic Fall, Vent Tremor, and One Very Loud Blast: Acoustic Analysis of the 14 July 2013 Vulcanian Eruption at Tungurahua, Ecuador.

    NASA Astrophysics Data System (ADS)

    Anderson, J.; Johnson, J. B.; Steele, A. L.; Anzieta, J. C.; Ortiz, H. D.; Hall, M. L.; Ruiz, M. C.

    2014-12-01

    Acoustic recordings reveal a variety of volcanic activities during an exceptionally loud vulcanian eruption at Tungurahua. A period of several months of mild surface activity came to an abrupt end with the emission of a powerful blast wave heard at least 180 km away. Sensors 2080 m from the vent recorded a stepped rise to its maximum overpressure of 1220 Pa (corresponding to a sound pressure level of 156 dB) and its unusually long dominant period of 5.6 s. We discuss source processes that produced the blast wave, considering that wave propagation could be nonlinear near the vent because of high overpressures. More than an hour of acoustic activity was recorded after the blast wave, including sound from falling ballistics, reflections of the blast wave from nearby mountains, pyroclastic density currents, and acoustic tremor at the vent. Glitches in the acoustic records related to plume lightning were also serendipitously observed, although thunder could not be unambiguously identified. We discuss acoustic signatures of falling ballistics and pyroclastic density currents and how array-style deployments and analytic methods can be used to reveal them. Placement of sensors high on the volcano's slopes facilitated resolving these distinct processes. This study demonstrates that near-vent, array-style acoustic installations can be used to monitor various types of volcanic activity.

  19. QRev—Software for computation and quality assurance of acoustic doppler current profiler moving-boat streamflow measurements—User’s manual for version 2.8

    USGS Publications Warehouse

    Mueller, David S.

    2016-01-01

    The software program, QRev computes the discharge from moving-boat acoustic Doppler current profiler measurements using data collected with any of the Teledyne RD Instrument or SonTek bottom tracking acoustic Doppler current profilers. The computation of discharge is independent of the manufacturer of the acoustic Doppler current profiler because QRev applies consistent algorithms independent of the data source. In addition, QRev automates filtering and quality checking of the collected data and provides feedback to the user of potential quality issues with the measurement. Various statistics and characteristics of the measurement, in addition to a simple uncertainty assessment are provided to the user to assist them in properly rating the measurement. QRev saves an extensible markup language file that can be imported into databases or electronic field notes software. The user interacts with QRev through a tablet-friendly graphical user interface. This report is the manual for version 2.8 of QRev.

  20. Your Glucose Meter

    MedlinePlus

    ... by Audience For Women Women's Health Topics Your Glucose Meter Share Tweet Linkedin Pin it More sharing ... Español Basic Facts 7 Tips for Testing Your Blood Sugar and Caring for Your Meter Glucose meters test ...

  1. Cause and solution for false upstream boat velocities measured with a StreamPro acoustic doppler current profiler

    USGS Publications Warehouse

    Mueller, David S.; Rehmel, Mike S.; Wagner, Chad R.

    2007-01-01

    In 2003, Teledyne RD Instruments introduced the StreamPro acoustic Doppler current profiler which does not include an internal compass. During stationary moving-bed tests the StreamPro often tends to swim or kite from the end of the tether (the instrument rotates then moves laterally in the direction of the rotation). Because the StreamPro does not have an internal compass, it cannot account for the rotation. This rotation and lateral movement of the StreamPro on the end of the tether generates a false upstream velocity, which cannot be easily distinguished from a moving-bed bias velocity. A field test was completed to demonstrate that this rotation and lateral movement causes a false upstream boat velocity. The vector dot product of the boat velocity and the unit vector of the depth-averaged water velocity is shown to be an effective method to account for the effect of the rotation and lateral movement.

  2. Application of the loop method for correcting acoustic doppler current profiler discharge measurements biased by sediment transport

    USGS Publications Warehouse

    Mueller, David S.; Wagner, Chad R.

    2006-01-01

    A systematic bias in discharge measurements made with an acoustic Doppler current profiler (ADCP) is attributed to the movement of sediment near the streambed-an issue widely acknowledged by the scientific community. This systematic bias leads to an underestimation of measured velocity and discharge. The integration of a differentially corrected Global Positioning System (DGPS) to track the movement of the ADCP can be used to avoid the systematic bias associated with a moving bed. DGPS systems, however, cannot provide consistently accurate positions because of multipath errors and satellite signal reception problems on waterways with dense tree canopy along the banks, in deep valleys or canyons, and near bridges. An alternative method of correcting for the moving-bed bias was investigated by the U.S. Geological Survey.

  3. Gamma radiation field intensity meter

    DOEpatents

    Thacker, L.H.

    1994-08-16

    A gamma radiation intensity meter measures dose rate of a radiation field. The gamma radiation intensity meter includes a tritium battery emitting beta rays generating a current which is essentially constant. Dose rate is correlated to an amount of movement of an electroscope element charged by the tritium battery. Ionizing radiation decreases the voltage at the element and causes movement. A bleed resistor is coupled between the electroscope support element or electrode and the ionization chamber wall electrode. 4 figs.

  4. Gamma radiation field intensity meter

    DOEpatents

    Thacker, Louis H.

    1995-01-01

    A gamma radiation intensity meter measures dose rate of a radiation field. The gamma radiation intensity meter includes a tritium battery emitting beta rays generating a current which is essentially constant. Dose rate is correlated to an amount of movement of an electroscope element charged by the tritium battery. Ionizing radiation decreases the voltage at the element and causes movement. A bleed resistor is coupled between the electroscope support element or electrode and the ionization chamber wall electrode.

  5. Gamma radiation field intensity meter

    DOEpatents

    Thacker, Louis H.

    1994-01-01

    A gamma radiation intensity meter measures dose rate of a radiation field. The gamma radiation intensity meter includes a tritium battery emitting beta rays generating a current which is essentially constant. Dose rate is correlated to an amount of movement of an electroscope element charged by the tritium battery. Ionizing radiation decreases the voltage at the element and causes movement. A bleed resistor is coupled between the electroscope support element or electrode and the ionization chamber wall electrode.

  6. Gamma radiation field intensity meter

    DOEpatents

    Thacker, L.H.

    1995-10-17

    A gamma radiation intensity meter measures dose rate of a radiation field. The gamma radiation intensity meter includes a tritium battery emitting beta rays generating a current which is essentially constant. Dose rate is correlated to an amount of movement of an electroscope element charged by the tritium battery. Ionizing radiation decreases the voltage at the element and causes movement. A bleed resistor is coupled between the electroscope support element or electrode and the ionization chamber wall electrode. 4 figs.

  7. Use of a 600-kHz Acoustic Doppler Current Profiler to measure estuarine bottom type, relative abundance of submerged aquatic vegetation, and eelgrass canopy height

    NASA Astrophysics Data System (ADS)

    Warren, Joseph D.; Peterson, Bradley J.

    2007-03-01

    The acoustic backscatter intensity signal from a high-frequency (600 kHz) Acoustic Doppler Current Profiler (ADCP) was used to categorize four different types of bottom habitat (sand, mud, sparse and dense vegetation) in a shallow-water estuary (Shinnecock Bay, NY, USA). A diver survey of the bay measured sediment and bottom vegetation characteristics at 85 sites within the bay. These data were used to groundtruth the acoustic data. Acoustic data were collected at four sites with known bottom types and used to develop an algorithm that could categorize the bottom type. The slope of the echo intensity profile close to the bottom was used to determine the bottom type and the relative numerical density (sparse or dense) of Submerged Aquatic Vegetation (SAV). In areas where eelgrass ( Zostera marina) was the dominant SAV species, the intensity profile data were analyzed to measure the height of the vegetation canopy. An acoustic survey which categorized the bottom type of the bay was conducted from a small vessel. The percentage of sampled sites categorized as each bottom habitat type from the acoustic survey was similar to those obtained by the diver survey. These methods may provide a means to rapidly survey estuarine habitats and measure spatial and temporal variations in SAV populations, as well as changes in the height of the eelgrass canopy.

  8. LINEAR COUNT-RATE METER

    DOEpatents

    Henry, J.J.

    1961-09-01

    A linear count-rate meter is designed to provide a highly linear output while receiving counting rates from one cycle per second to 100,000 cycles per second. Input pulses enter a linear discriminator and then are fed to a trigger circuit which produces positive pulses of uniform width and amplitude. The trigger circuit is connected to a one-shot multivibrator. The multivibrator output pulses have a selected width. Feedback means are provided for preventing transistor saturation in the multivibrator which improves the rise and decay times of the output pulses. The multivibrator is connected to a diode-switched, constant current metering circuit. A selected constant current is switched to an averaging circuit for each pulse received, and for a time determined by the received pulse width. The average output meter current is proportional to the product of the counting rate, the constant current, and the multivibrator output pulse width.

  9. Current-driven ion-acoustic and potential-relaxation instabilities excited in plasma plume during electron beam welding

    SciTech Connect

    Trushnikov, D. N.; Mladenov, G. M. Koleva, E. G.; Belenkiy, V. Ya. Varushkin, S. V.

    2014-04-15

    Many papers have sought correlations between the parameters of secondary particles generated above the beam/work piece interaction zone, dynamics of processes in the keyhole, and technological processes. Low- and high-frequency oscillations of the current, collected by plasma have been observed above the welding zone during electron beam welding. Low-frequency oscillations of secondary signals are related to capillary instabilities of the keyhole, however; the physical mechanisms responsible for the high-frequency oscillations (>10 kHz) of the collected current are not fully understood. This paper shows that peak frequencies in the spectra of the collected high-frequency signal are dependent on the reciprocal distance between the welding zone and collector electrode. From the relationship between current harmonics frequency and distance of the collector/welding zone, it can be estimated that the draft velocity of electrons or phase velocity of excited waves is about 1600 m/s. The dispersion relation with the properties of ion-acoustic waves is related to electron temperature 10 000 K, ion temperature 2 400 K and plasma density 10{sup 16} m{sup −3}, which is analogues to the parameters of potential-relaxation instabilities, observed in similar conditions. The estimated critical density of the transported current for creating the anomalous resistance state of plasma is of the order of 3 A·m{sup −2}, i.e. 8 mA for a 3–10 cm{sup 2} collector electrode. Thus, it is assumed that the observed high-frequency oscillations of the current collected by the positive collector electrode are caused by relaxation processes in the plasma plume above the welding zone, and not a direct demonstration of oscillations in the keyhole.

  10. Portable peak flow meters.

    PubMed

    McNaughton, J P

    1997-02-01

    There are several portable peak flow meters available. These instruments vary in construction and performance. Guidelines are recommended for minimum performance and testing of portable peak flow meters, with the aim of establishing a procedure for standardizing all peak flow meters. Future studies to clarify the usefulness of mechanical test apparatus and clinical trials of peak flow meters are also recommended. PMID:9098706

  11. Balanced Flow Meters without Moving Parts

    NASA Technical Reports Server (NTRS)

    Kelley, Anthony R.; VanBuskirk, Paul

    2008-01-01

    Balanced flow meters are recent additions to an established class of simple, rugged flow meters that contain no moving parts in contact with flow and are based on measurement of pressure drops across objects placed in flow paths. These flow meters are highly accurate, minimally intrusive, easily manufacturable, and reliable. A balanced flow meter can be easily mounted in a flow path by bolting it between conventional pipe flanges. A balanced flow meter can be used to measure the flow of any of a variety of liquids or gases, provided that it has been properly calibrated. Relative to the standard orifice-plate flow meter, the balanced flow meter introduces less turbulence and two times less permanent pressure loss and is therefore capable of offering 10 times greater accuracy and repeatability with less dissipation of energy. A secondary benefit of the reduction of turbulence is the reduction of vibration and up to 15 times less acoustic noise generation. Both the balanced flow meter and the standard orifice-plate flow meter are basically disks that contain holes and are instrumented with pressure transducers on their upstream and downstream faces. The most obvious difference between them is that the standard orifice plate contains a single, central hole while the balanced flow meter contains multiple holes. The term 'balanced' signifies that in designing the meter, the sizes and locations of the holes are determined in an optimization procedure that involves balancing of numerous factors, including volumetric flow, mass flow, dynamic pressure, kinetic energy, all in an effort to minimize such undesired effects as turbulence, pressure loss, dissipation of kinetic energy, and non-repeatability and nonlinearity of response over the anticipated range of flow conditions. Due to proper balancing of these factors, recent testing demonstrated that the balanced flow-meter performance was similar to a Venturi tube in both accuracy and pressure recovery, but featured reduced

  12. Diel vertical migrations of Meganyctiphanes norvegica in the Kattegat: Comparison of net catches and measurements with Acoustic Doppler Current Profilers

    NASA Astrophysics Data System (ADS)

    Buchholz, F.; Buchholz, C.; Reppin, J.; Fischer, J.

    1995-03-01

    Diel vertical migration of a stable and well-defined population of Nordic krill, Meganyctiphanes norvegica (Crustacea, Euphausiacea) was investigated during eight days in August 1989, in the Läsö-Deep, East of the Danish island Läsö. Net catches with a multi-net (MOCNESS) and measurements with a moored and a shipboard Acoustic Doppler Current Profiler (ADCP) were compared. Backscattered energy as a measure for biomass gave good correlations to the dry weight of M. norvegica and smaller zooplankton from net catches. Diel migratory patterns matched well, as determined, parallel with both methods. Migratory vertical velocity was determined with ADCP at 2 3 cm sec-1. The potential for the use of ADCPs for biological investigation is discussed. Vertical migration was dependent on environmental parameters. The krill did not cross a temperature barrier of 14°C, although rich food sources were situated beyond it. Differences in salinity did not play a role. Currents were involved in plankton distribution. Light was an important Zeitgeber (synchronizer) and determined the density of the krill aggregations. Feeding behaviour did not interfere with the light-induced migratory pattern of Nordic krill at the Läsö-Deep.

  13. Shipboard acoustic doppler current profiler data collected during the Western Tropical Atlantic Experiment (WESTRAX) 1991. Technical memo

    SciTech Connect

    Routt, J.A.; Wilson, W.D.

    1992-11-01

    The long-term goal of ongoing and future research in the western tropical Atlantic is to estimate the cross-equatorial transport of water and heat. The overall goals of those involved in the Western Tropical Atlantic Experiment (WESTRAX) are (a) to describe the annual cycle in the large-scale structure of the velocity and hydrographic properties over the full water column in the western tropical Atlantic Ocean between the equator and 15 degrees N, and (b) to compare data and models in order to better understand the physics of the regional circulation in the broader context of Atlantic basin thermohaline circulation. The results of this combined effort will greatly improve our understanding of this complex boundary current region and establish the basis for efficient long-term climatic monitoring of the critical meridional fluxes of mass and heat across the tropical Atlantic. This report presents the Acoustic Doppler Current Profiler (ADCP) data obtained during (ACCP) Atlantic Climate Change Program cruises in the western subtropical and tropical Atlantic in January, June and September 1991.

  14. Barometric and magnetic observations of vertical acoustic resonance and resultant generation of field-aligned current associated with earthquakes

    NASA Astrophysics Data System (ADS)

    Iyemori, Toshihiko; Tanaka, Yoshikazu; Odagi, Yoko; Sano, Yasuharu; Takeda, Masahiko; Nose, Masahito; Utsugi, Mitsuru; Rosales, Domingo; Choque, Edwin; Ishitsuka, Jose; Yamanaka, Sadato; Nakanishi, Kunihito; Matsumura, Mitsuru; Shinagawa, Hiroyuki

    2013-08-01

    Three rare occasions are introduced, where the excitation of vertical acoustic resonance between the ground and the ionosphere, and the resultant generation of a field-aligned current, just after earthquakes are observationally confirmed. In the case of two inland earthquakes, barometric observations very close to the epicenters (i.e., only 30 km apart) were available, and they showed a sharp spectral peak which appeared within one hour after the origin time and lasted a few hours. The observed periods of the spectral peaks around 260 seconds are close to the period of the theoretically-expected fundamental mode of the resonance. On the other hand, magnetic observations on the ground showed a dominant period at 220-230 seconds which corresponds to the first overtone among theoretically-expected major resonance peaks. In the third case, i.e., during the 2010 Chile earthquake, a long-period magnetic oscillation in the east-west direction, which has two major resonance periods at 265 and 190-195 seconds, was observed on the night-side magnetic dip equator in Peru, where the distance is more than 2600 km from the epicenter, under a very quiet geomagnetic condition. The oscillation was interpreted as the effect of field-aligned current generated through a dynamo process in the ionosphere over the epicenter caused by the resonance.

  15. Mass meters for liquid measurement

    SciTech Connect

    Apple, C.

    1995-12-01

    Flowmeters that are capable of providing a direct mass flow measurement include: Coriolis, thermal, gyroscopic and angular momentum. However, Coriolis meters are the only commercially viable device that can cover the breadth of measurements required by the petroleum industry. In addition to providing a direct mass flow measurement, Coriolis meters are extremely accurate, typically {+-}0.1 % to {+-}0.2 %. The advantage of measuring mass is that the mass of a fluid is unaffected by changes in process temperature and pressure. Whereas, volume measurements must be corrected to standard conditions of temperature and pressure for accounting purposes. Although measuring a product on a mass basis would be the simplest approach, most petroleum products are accounted for on a volume basis. This is primarily because only volumetric flowmeters were available prior to the introduction of industrial quality Coriolis meter in the early 1980`s. Due to the lack of means to perform a mass measurement, the petroleum industry has standardized on volume measurement. Systems and procedures are currently in place for performing and verifying volume measurements. Therefore, the petroleum industry will be slow in moving to mass measurement. Coriolis meters are currently gaining acceptance in the petroleum industry for the metering of light hydrocarbons, which are difficult to properly account for on a volume basis. However, due to the many advantages that Coriolis meters provide, they will become a preferred flow measurement device for all areas of petroleum measurement.

  16. Seasonal suspended particles distribution patterns in Western South Yellow Sea based on Acoustic Doppler Current Profiler observation

    NASA Astrophysics Data System (ADS)

    Li, Jianchao; Li, Guangxue; Xu, Jishang; Qiao, Lulu; Dong, Ping; Ding, Dong; Liu, Shidong; Sun, Pingkuo

    2015-06-01

    An Acoustic Doppler Current Profiler (ADCP) observation site was set up in the Western South Yellow Sea from 2012 to 2013 to study the local suspended particle matters (SPM) distribution pattern. The SPM concentration could be semi-quantitatively represented by backscatter intensity (Sv), converted by the echo intensity (EI) of ADCP. Results show two types of SPM in the water column: the quasi-biological SPM and quasi-mineral SPM. The quasi-biological SPM mainly exists in summer half year and is concentrated above the thermocline. It has periodically diurnal variations with high concentration at night and low concentration in the daytime. The quasi-mineral SPM is located in lower part of the water column, with similar relation to monthly tidal current variation all year round. However, the daily quasi-mineral SPM distribution patterns vary between summer and winter half year. The sunlight is thought to be the origin factor leading to the diurnally vertical motion of the biological features, which might cause the diurnal Sv variation. Unlike in winter half year when tidal current is relatively single driving force of the monthly SPM pattern, the high speed current near the thermocline is also responsible for the concentration of quasi-mineral SPM in summer half year. The sediment input difference between summer and winter half year contribute to the varied daily variation of quasi-mineral SPM with re-suspended SPM in winter and sediments from Yellow Sea Mud Area (YSMA) in summer. The seasonal variations in hydrodynamics, water structure and heavy-wind incidents are the primary factors influencing the differential seasonal SPM distribution patterns.

  17. Strong Amplification of Coherent Acoustic Phonons by Intraminiband Currents in a Semiconductor Superlattice.

    PubMed

    Shinokita, Keisuke; Reimann, Klaus; Woerner, Michael; Elsaesser, Thomas; Hey, Rudolf; Flytzanis, Christos

    2016-02-19

    Sound amplification in an electrically biased superlattice (SL) is studied in optical experiments with 100 fs time resolution. Coherent SL phonons with frequencies of 40, 375, and 410 GHz give rise to oscillatory reflectivity changes. With currents from 0.5 to 1.3 A, the Fourier amplitude of the 410 GHz phonon increases by more than a factor of 2 over a 200 ps period. This amplification is due to stimulated Čerenkov phonon emission by electrons undergoing intraminiband transport. The gain coefficient of 8×10^{3}  cm^{-1} is reproduced by theoretical calculations and holds potential for novel sub-THz phonon emitters. PMID:26943546

  18. The Acoustic Doppler Current Profiler (adcp) as a Tool for Ocean Exploration

    NASA Astrophysics Data System (ADS)

    Rossby, H. T.; Flagg, C. N.; Ortner, P. B.

    2010-12-01

    Although the ADCP has been around for three decades it remains somewhat underappreciated for its excellent exploratory potential in several areas. First and perhaps foremost because oceanographers have always been handicapped in their ability to resolve horizontal patterns below the surface, the ADCP opens up a powerful and very cost-effective window into the ocean water column to explore the meso- and submesoscale velocity field at very high resolution. This is particularly true when ADCP data are collected from just a single instrument mounted on a vessel operating repeatedly over an extended period of time in an area or along a route. The ADCP greatly expands upon hydrographic and XBT information by directly measuring the velocity field accurately without any assumptions about geostrophy or the velocity of reference layers. Second, vessels in transit can characterize currents and eddy activities across contrasting oceanic regimes and highlight their relation to the steering role of bottom topography. Third, even though the ADCP is a single frequency device the backscatter signal recorded by the ADCP is showing considerable skill in revealing space-time patterns of biomass variability. Here, through data we have taken over the past ten years, we survey the ADCP’s future as a tool of exploration across several dimensions: space, time, and parameter (physics and biology). Today, thanks to the ADCP we have a far more accurate picture of the velocity and vorticity structure of fronts and eddies. At the surface a front is simply a transition between different water masses, but the actual transition will often consist a water-mass and potential vorticity jump on a significantly smaller scale within the frontal feature. The same applies to the boundaries of rings and lenses. Commercial vessels equipped with ADCPs operating on a repeat schedule can document underlying patterns that single transects or cruises cannot detect due to inherent eddy activity. Newly

  19. An Acoustic Doppler Current Profiler Survey of Flow Velocities in Detroit River, a Connecting Channel of the Great Lakes

    USGS Publications Warehouse

    Holtschlag, David J.; Koschik, John A.

    2003-01-01

    Acoustic Doppler current profilers (ADCP) were used to survey flow velocities in Detroit River from July 8-19, 2002, as part of a study to assess the susceptibility of public water intakes to contaminants on the St. Clair-Detroit River Waterway. More than 3.5 million point velocities were measured at 130 cross sections. Cross sections were generally spaced about 1,800 ft apart along the river from the head of Detroit River at the outlet of Lake St. Clair to the mouth of Detroit River on Lake Erie. Two transects were surveyed at each cross section, one in each direction across the river. Along each transect, velocity profiles were generally obtained 0.8-2.2 ft apart. At each velocity profile, average water velocity data were obtained at 1.64 ft intervals of depth. The raw position and velocity data from the ADCP field survey were adjusted for local magnetic anomalies using global positioning system (GPS) measurements at the end points of the transects. The adjusted velocity and ancillary data can be retrieved though the internet and extracted to column-oriented data files.

  20. An acoustic doppler current profiler survey of flow velocities in St. Clair River, a connecting channel of the Great Lakes

    USGS Publications Warehouse

    Holtschlag, David J.; Koschik, John A.

    2003-01-01

    Acoustic Doppler current profilers (ADCP) were used to measure flow velocities in St. Clair River during a survey in May and June of 2002, as part of a study to assess the susceptibility of public water intakes to contaminants on the St. Clair-Detroit River Waterway. The survey provides 2.7 million point velocity measurements at 104 cross sections. Sections are spaced about 1,630 ft apart along the river from Port Huron to Algonac, Michigan, a distance of 28.6 miles. Two transects were obtained at each cross section, one in each direction across the river. Along each transect, velocity profiles were obtained 2-4 ft apart. At each velocity profile, average water velocity data were obtained at 1.64 ft intervals of depth. The raw position and velocity data from the ADCP field survey were adjusted for local magnetic anomalies using global positioning system (GPS) measurements at the end points of the transects. The adjusted velocity and ancillary data can be retrieved through the internet and extracted to column-oriented data files.

  1. Gap-Prepulse Inhibition of the Acoustic Startle Reflex (GPIAS) for Tinnitus Assessment: Current Status and Future Directions

    PubMed Central

    Galazyuk, Alexander; Hébert, Sylvie

    2015-01-01

    The progress in the field of tinnitus largely depends on the development of a reliable tinnitus animal model. Recently, a new method based on the acoustic startle reflex modification was introduced for tinnitus screening in laboratory animals. This method was enthusiastically adopted and now widely used by many scientists in the field due to its seeming simplicity and a number of advantages over the other methods of tinnitus assessment. Furthermore, this method opened an opportunity for tinnitus assessment in humans as well. Unfortunately, multiple modifications of data collection and interpretation implemented in different labs make comparisons across studies very difficult. In addition, recent animal and human studies have challenged the original “filling-in” interpretation of the paradigm. Here, we review the current literature to emphasize on the commonalities and differences in data collection and interpretation across laboratories that are using this method for tinnitus assessment. We also propose future research directions that could be taken in order to establish whether or not this method is warranted as an indicator of the presence of tinnitus. PMID:25972836

  2. Acoustic Doppler current profiling from the JGOFS Arabian sea cruises aboard the RV T.G. Thompson

    SciTech Connect

    Kim, Hyun-Sook; Flagg, C.N.; Shi, Yan

    1996-06-01

    Acoustic Doppler current profiler (ADCP) data is part of the core data for the U.S. JGOFS Arabian Sea project, along with hydrographic and nutrient data. Seventeen cruises are scheduled to take place between September 1994 and January 1996 on the R/V T.G. Thompson. They are numbered consecutively from the ship`s commissioning with the first JGOFS cruise designated TN039. Table 1 lists start and end dates of each cruise with its mission. All but the first cruise have been or will be staged from Muscat, Oman. Each cruise is scheduled for a duration of between two weeks and one month. Seven of the cruises, referred to as process cruises, follow a standard cruise track, taking hydrographic, chemical and biological measurements. The rest of the cruises, which take place generally within the standard cruise region defined by a set track, are for the deployment and recovery of moored equipments and towing of a SeaSoar. ADCP data are collected using an autonomous data acquisition system developed for ship-of-opportunity cruises, named the AutoADCP system. The system is an extension of RD instrument`s DAS version 2.48 using enhancements made possible with {open_quotes}user-exit{close_quotes} programs. It makes it possible to collect ADCP data without the constant monitoring usually necessary and insures constant data coverage and uniform data quality.

  3. Gap-Prepulse Inhibition of the Acoustic Startle Reflex (GPIAS) for Tinnitus Assessment: Current Status and Future Directions.

    PubMed

    Galazyuk, Alexander; Hébert, Sylvie

    2015-01-01

    The progress in the field of tinnitus largely depends on the development of a reliable tinnitus animal model. Recently, a new method based on the acoustic startle reflex modification was introduced for tinnitus screening in laboratory animals. This method was enthusiastically adopted and now widely used by many scientists in the field due to its seeming simplicity and a number of advantages over the other methods of tinnitus assessment. Furthermore, this method opened an opportunity for tinnitus assessment in humans as well. Unfortunately, multiple modifications of data collection and interpretation implemented in different labs make comparisons across studies very difficult. In addition, recent animal and human studies have challenged the original "filling-in" interpretation of the paradigm. Here, we review the current literature to emphasize on the commonalities and differences in data collection and interpretation across laboratories that are using this method for tinnitus assessment. We also propose future research directions that could be taken in order to establish whether or not this method is warranted as an indicator of the presence of tinnitus. PMID:25972836

  4. Tutorial on architectural acoustics

    NASA Astrophysics Data System (ADS)

    Shaw, Neil; Talaske, Rick; Bistafa, Sylvio

    2002-11-01

    This tutorial is intended to provide an overview of current knowledge and practice in architectural acoustics. Topics covered will include basic concepts and history, acoustics of small rooms (small rooms for speech such as classrooms and meeting rooms, music studios, small critical listening spaces such as home theatres) and the acoustics of large rooms (larger assembly halls, auditoria, and performance halls).

  5. Field evaluation of boat-mounted acoustic Doppler instruments used to measure streamflow

    USGS Publications Warehouse

    Mueller, D.S.

    2003-01-01

    The use of instruments based on the Doppler principle for measuring water velocity and computing discharge is common within the U.S. Geological Survey (USGS). The instruments and software have changed appreciably during the last 5 years; therefore, the USGS has begun field validation of the instruments used to make discharge measurements from a moving boat. Instruments manufactured by SonTek/YSI and RD Instruments, Inc. were used to collect discharge data at five different sites. One or more traditional discharge measurements were made using a Price AA current meter and standard USGS procedures concurrent with the acoustic instruments at each site. Discharges measured with the acoustic instruments were compared with discharges measured with Price AA current meters and the USGS stage-discharge rating for each site. The mean discharges measured by each acoustic instrument were within 5 percent of the Price AA-based measurement and (or) discharge from the stage-discharge rating.

  6. Advanced metering techniques

    SciTech Connect

    Szydlowski, R.F.

    1993-01-01

    The goal of the US Department of Energy Federal Energy Management Program (FEMP) is to facilitate energy-efficiency improvements at federal facilities. This is accomplished by a balanced program of technology development, facility assessment, and use of cost-sharing procurement mechanisms. Technology development focuses upon the tools and procedures used to identify and evaluate efficiency improvements. For facility assessment, FEMP provides metering equipment and trained analysts to federal agencies exhibiting a commitment to improve energy-use efficiency. To assist in implementing energy-efficiency measures, FEMP helps federal agencies with identifying efficiency opportunities and in implementing energy-efficiency and demand-side management programs at federal sites. As the lead laboratory for FEMP, Pacific Northwest Laboratory (PNL) provides technical assistance to federal agencies to better understand and characterize energy systems. The US Army Forces Command (FORSCOM) has tasked PNL to provide technical assistance to characterize and modernize energy systems at FORSCOM installations. As part of that technical assistance, PNL performed an in-depth examination of automatic meter-reading system technologies currently available. The operating characteristics and relative merits of all the major systems were reviewed in the context of applicability to federal installations. That review is documented in this report.

  7. A Matter of Meter

    ERIC Educational Resources Information Center

    Harrison, David L.

    2006-01-01

    Writing verse is a learning experience. Arranging words, sounds and syllables can turn everyday language into metered language (language that can be measured), and metered language is the definition of verse. This article discusses the use of meter in helping students establish sets of syllables and lines that can be counted, enabling them to…

  8. The Physical Context of the Southern Ocean Iron Experiment as Observed by Shipboard Acoustic Doppler Current Profilers

    NASA Astrophysics Data System (ADS)

    Brewster, J.; Pierce, S. D.

    2002-12-01

    The Southern Ocean Iron Experiment in January-February 2002 involved three ships making numerous measurements to help quantify and study two iron-infused patches of water. The main purpose of the study was to investigate the biological and chemical effects of iron fertilization on phytoplankton productivity. Physical processes in the Southern Ocean play a large role in the formation, evolution, and eventual dispersion of natural phytoplankton patches. The Northern (56 S) and Southern (66.5 S) patches were infused with iron sulfate three and four times, respectively, and tracked over a seven week period. Two of the ships, the R/V Revelle and the R/V Melville, were outfitted with 150 kHz narrowband acoustic Doppler current profilers. Good quality velocity data between 20 and 300 m depths are available continuously along the shiptracks. The available transects running south in the vicinity of 170 W, from 52-66.5 S, reveal the zonally banded velocity structure characteristic of the Antarctic Circumpolar Current. To the north of the 59-61 S Polar Frontal zone, mesoscale bands of eastward currents up to 0.4 m/s alternate with generally smaller westward bands. Farther south, the alternating structure continues but with smaller eastward velocities of about 0.2 m/s. The Northern iron patch was successfully created in a relatively low-velocity region amidst strong velocities immediately north and south. The overall mean velocity during the initial Northern patch occupation by the R/V Revelle (12-19 January) was small and northward at 0.1 m/s. By the second Revelle occupation of the Northern patch (8-10 February), however, the mean patch velocity was 0.2 m/s to the east-northeast. Significantly, the patch at this time extended across the flank of a strong eastward jet, associated with a sharp surface temperature change from 8-11 C. Whereas the northern end of the North patch experienced a strong 0.5 m/s northeast velocity, the southern end remained in a low-velocity region

  9. Acoustic neuroma

    MedlinePlus

    Vestibular schwannoma; Tumor - acoustic; Cerebellopontine angle tumor; Angle tumor ... Acoustic neuromas have been linked with the genetic disorder neurofibromatosis type 2 (NF2). Acoustic neuromas are uncommon.

  10. Comparison of bottom-track to global positioning system referenced discharges measured using an acoustic Doppler current profiler

    USGS Publications Warehouse

    Wagner, C.R.; Mueller, D.S.

    2011-01-01

    A negative bias in discharge measurements made with an acoustic Doppler current profiler (ADCP) can be caused by the movement of sediment on or near the streambed. The integration of a global positioning system (GPS) to track the movement of the ADCP can be used to avoid the systematic negative bias associated with a moving streambed. More than 500 discharge transects from 63 discharge measurements with GPS data were collected at sites throughout the US, Canada, and New Zealand with no moving bed to compare GPS and bottom-track-referenced discharges. Although the data indicated some statistical bias depending on site conditions and type of GPS data used, these biases were typically about 0.5% or less. An assessment of differential correction sources was limited by a lack of data collected in a range of different correction sources and different GPS receivers at the same sites. Despite this limitation, the data indicate that the use of Wide Area Augmentation System (WAAS) corrected positional data is acceptable for discharge measurements using GGA as the boat-velocity reference. The discharge data based on GPS-referenced boat velocities from the VTG data string, which does not require differential correction, were comparable to the discharges based on GPS-referenced boat velocities from the differentially-corrected GGA data string. Spatial variability of measure discharges referenced to GGA, VTG and bottom-tracking is higher near the channel banks. The spatial variability of VTG-referenced discharges is correlated with the spatial distribution of maximum Horizontal Dilution of Precision (HDOP) values and the spatial variability of GGA-referenced discharges is correlated with proximity to channel banks. ?? 2011 Published by Elsevier B.V.

  11. Acoustic doppler current profiling from the JGOFS Arabian Sea cruises aboard the RV T.G. Thompson

    SciTech Connect

    Flagg, C.N.; Shi, Y.

    1995-04-01

    Acoustic Doppler Current Profiler (ADCP) data from the R/V T.G. THOMPSON is part of the core data for the US JGOFS Arabian Sea project along with hydrographic and nutrient data. Seventeen cruises on the THOMPSON are scheduled to take place between September 1994 and January 1996. The first of these cruises, a transit of the R/V THOMPSON into the northern Arabian Sea area from Singapore, was a calibration and training cruise that took place between September 18 and October 7, 1994. (The cruises on the THOMPSON are numbered consecutively from the ship`s commissioning with the first JOGFS cruise designated TN039.) The remaining cruises have been and will be staged from Muscat, Oman. Seven of these cruises, referred to as process cruises, will follow a set cruise track, making hydrographic, chemical and biological measurements. The remainder of the cruises while not restricted to the set cruise track, will generally stay within the region defined by the track during the deployment and retrieval of moored equipment and the towing of a SeaSoar. Each cruise will last between two weeks and one month. ADCP data will be collected on all the JGOFS Arabian Sea cruises using an autonomous data acquisition system developed for ship-of-opportunity cruises. This system, referred to as the AutoADCP, makes it possible to collect the ADCP data without the constant monitoring usually necessary and assures constant data coverage and uniform data quality. The AutoADCP system is an extension of RD Instrument`s DAS version 2.48 using enhancements made possible with ``user exit`` programs. This data report presents ADCP results from the first four JGOFS cruises, TN039 through TN042, concentrating on the data collection and processing methods.

  12. Acoustic Properties of Return Strokes and M-components From Rocket-Triggered Lightning

    NASA Astrophysics Data System (ADS)

    Dayeh, M. A.; Fuselier, S. A.; Dwyer, J. R.; Uman, M. A.; Jordan, D.; Carvalho, F. L.; Rassoul, H.

    2015-12-01

    Using a linear, one-dimensional array of 15 microphones situated 95 meters from the lightning channel; we measure the acoustic signatures from 11 triggered-lightning events comprising 41 return strokes and 28 M-components. Measurements were taken at the International Center for Lightning Research and Testing (ICLRT) in Camp Blanding, FL during the summer of 2014. Recently, we reported that beamforming signal processing enables acoustic imaging of the lightning channel at high frequencies (Dayeh et al. 2015). Following up on the work, we report on the characteristics of the acoustic measurements in terms of sound pressure amplitude, peak currents, power spectral density (PSD) properties, and the inferred energy input. In addition, we find that M-component do not create acoustic signatures in most occasions; we discuss these cases in context of the associated current amplitude, rise time, and background continuing current.

  13. Seepage meters and Bernoulli's revenge

    USGS Publications Warehouse

    Shinn, E.A.; Reich, C.D.; Hickey, T.D.

    2002-01-01

    Evaluation of seepage data from a network of 50 permanently deployed submarine seepage meters, specially constructed from fiberglass, indicates that the devices artificially advect (Bernoulli effect) shallow ground water. Reverse flow into the rock was not observed even when adjacent piezometers installed 2-m to 20-m below the rock-water interface indicated negative groundwater heads. Quantitative testing of five different designs, including conventional end-of-oil-drum designs, indicates that meters presenting positive relief on the sea floor are subject to the Bernoulli effect when placed in areas where there are waves and/or currents. Advection does not appear to be caused by flexing of the collection bags.

  14. Net metering programs

    SciTech Connect

    Wan, Y H

    1996-12-01

    There has been a recent surge of interest from the renewable energy industry and environmental groups in net metering. The reason for this interest is that net metering is a simple, low-cost, and easily administered method to encourage direct customer investment in renewable energy technologies. The renewable energy industry supports net metering because it removes an economic disincentive for potential customers by increasing the value of the electricity generated by renewable energy technologies. Environmental groups support net metering because it promotes clean energy production. The concept of net metering programs is to allow the electric meters of customers with generating facilities to turn backwards when their generators are producing more energy than the customers` demand. Net metering allows customers to use their generation to offset their consumption over the entire billing period, not just instantaneously. This offset would enable customers with generating facilities to receive retail prices for more of the electricity they generate. Without a net metering program, utilities usually install a second meter to measure any electricity that flows back to the utility grid and purchase it at a rate that is much lower than the retail prices. There are various net metering programs in the country. Most are available to customer-owned small generating facilities only, some further restrict the eligibility to renewable energy technologies. This Topical Issues Brief discusses how these net metering programs have been implemented by different utilities an states, what the rationales are behind may net metering programs, and what the potential impact of net metering may be on the deployment of renewable energy technologies.

  15. Correcting acoustic Doppler current profiler discharge measurement bias from moving-bed conditions without global positioning during the 2004 Glen Canyon Dam controlled flood on the Colorado River

    USGS Publications Warehouse

    Gartner, J.W.; Ganju, N.K.

    2007-01-01

    Discharge measurements were made by acoustic Doppler current profiler at two locations on the Colorado River during the 2004 controlled flood from Glen Canyon Dam, Arizona. Measurement hardware and software have constantly improved from the 1980s such that discharge measurements by acoustic profiling instruments are now routinely made over a wide range of hydrologic conditions. However, measurements made with instruments deployed from moving boats require reliable boat velocity data for accurate measurements of discharge. This is normally accomplished by using special acoustic bottom track pings that sense instrument motion over bottom. While this method is suitable for most conditions, high current flows that produce downstream bed sediment movement create a condition known as moving bed that will bias velocities and discharge to lower than actual values. When this situation exists, one solution is to determine boat velocity with satellite positioning information. Another solution is to use a lower frequency instrument. Discharge measurements made during the 2004 Glen Canyon controlled flood were subject to moving-bed conditions and frequent loss of bottom track. Due to site conditions and equipment availability, the measurements were conducted without benefit of external positioning information or lower frequency instruments. This paper documents and evaluates several techniques used to correct the resulting underestimated discharge measurements. One technique produces discharge values in good agreement with estimates from numerical model and measured hydrographs during the flood. ?? 2007, by the American Society of Limnology and Oceanography, Inc.

  16. The Development of Automated Detection Techniques for Passive Acoustic Monitoring as a Tool for Studying Beaked Whale Distribution and Habitat Preferences in the California Current Ecosystem

    NASA Astrophysics Data System (ADS)

    Yack, Tina M.

    The objectives of this research were to test available automated detection methods for passive acoustic monitoring and integrate the best available method into standard marine mammal monitoring protocols for ship based surveys. The goal of the first chapter was to evaluate the performance and utility of PAMGUARD 1.0 Core software for use in automated detection of marine mammal acoustic signals during towed array surveys. Three different detector configurations of PAMGUARD were compared. These automated detection algorithms were evaluated by comparing them to the results of manual detections made by an experienced bio-acoustician (author TMY). This study provides the first detailed comparisons of PAMGUARD automated detection algorithms to manual detection methods. The results of these comparisons clearly illustrate the utility of automated detection methods for odontocete species. Results of this work showed that the majority of whistles and click events can be reliably detected using PAMGUARD software. The second chapter moves beyond automated detection to examine and test automated classification algorithms for beaked whale species. Beaked whales are notoriously elusive and difficult to study, especially using visual survey methods. The purpose of the second chapter was to test, validate, and compare algorithms for detection of beaked whales in acoustic line-transect survey data. Using data collected at sea from the PAMGUARD classifier developed in Chapter 2 it was possible to measure the clicks from visually verified Baird's beaked whale encounters and use this data to develop classifiers that could discriminate Baird's beaked whales from other beaked whale species in future work. Echolocation clicks from Baird's beaked whales, Berardius bairdii, were recorded during combined visual and acoustic shipboard surveys of cetacean populations in the California Current Ecosystem (CCE) and with autonomous, long-term recorders at four different sites in the Southern

  17. Application of acoustic doppler current profilers for measuring three-dimensional flow fields and as a surrogate measurement of bedload transport

    USGS Publications Warehouse

    Conaway, J.S.

    2005-01-01

    Acoustic Doppler current profilers (ADCPs) have been in use in the riverine environment for nearly 20 years. Their application primarily has been focused on the measurement of streamflow discharge. ADCPs emit high-frequency sound pulses and receive reflected sound echoes from sediment particles in the water column. The Doppler shift between transmitted and return signals is resolved into a velocity component that is measured in three dimensions by simultaneously transmitting four independent acoustical pulses. To measure the absolute velocity magnitude and direction in the water column, the velocity magnitude and direction of the instrument must also be computed. Typically this is accomplished by ensonifying the streambed with an acoustical pulse that also provides a depth measurement for each of the four acoustic beams. Sediment transport on or near the streambed will bias these measurements and requires external positioning such as a differentially corrected Global Positioning Systems (GPS). Although the influence of hydraulic structures such as spur dikes and bridge piers is typically only measured and described in one or two dimensions, the use of differentially corrected GPS with ADCPs provides a fully three-dimensional measurement of the magnitude and direction of the water column at such structures. The measurement of these flow disturbances in a field setting also captures the natural pulsations of river flow that cannot be easily quantified or modeled by numerical simulations or flumes. Several examples of measured three-dimensional flow conditions at bridge sites throughout Alaska are presented. The bias introduced to the bottom-track measurement is being investigated as a surrogate measurement of bedload transport. By fixing the position of the ADCP for a known period of time the apparent velocity of the streambed at that position can be determined. Initial results and comparison to traditionally measured bedload values are presented. These initial

  18. Acoustic properties of triggered lightning

    NASA Astrophysics Data System (ADS)

    Dayeh, M. A.; Evans, N.; Ramaekers, J.; Trevino, J.; Rassoul, H.; Lucia, R. J.; Dwyer, J. R.; Uman, M. A.; Jordan, D. M.

    2014-12-01

    Acoustic signatures from rocket-triggered lightning are measured by a 15m long, one-dimensional microphone array consisting of 16 receivers situated 90 meters from the lightning channel. Measurements were taken at the International Center for Lightning Research and Testing (ICLRT) in Camp Blanding, FL during the summer of 2014. The linear array was oriented in an end-fire position so that the peak acoustic reception pattern can be steered vertically along the channel with a frequency-dependent spatial resolution, enabling us to sample the acoustic signatures from different portions along the lightning channel. We report on the characteristics of acoustic signatures associated with several return strokes in 6 measured flashes (total of 29 return strokes). In addition, we study the relationship between the amplitude, peak frequency, and inferred energy input of each stroke acoustic signature and the associated measured lightning parameters. Furthermore, challenges of obtaining acoustic measurements in thunderstorm harsh conditions and their countermeasures will also be discussed.

  19. Klamath River Water Quality and Acoustic Doppler Current Profiler Data from Link River Dam to Keno Dam, 2007

    USGS Publications Warehouse

    Sullivan, Annett B.; Deas, Michael L.; Asbill, Jessica; Kirshtein, Julie D.; Butler, Kenna; Stewart, Marc A.; Wellman, Roy W.; Vaughn, Jennifer

    2008-01-01

    In 2007, the U.S. Geological Survey, Watercourse Engineering, and the Bureau of Reclamation began a project to construct and calibrate a water quality and hydrodynamic model of the 21-mile reach of the Klamath River from Link River Dam to Keno Dam. To provide a basis for this work, data collection and experimental work were planned for 2007 and 2008. This report documents sampling and analytical methods and presents data from the first year of work. To determine water velocities and discharge, a series of cross-sectional acoustic Doppler current profiler (ADCP) measurements were made on the mainstem and four canals on May 30 and September 19, 2007. Water quality was sampled weekly at five mainstem sites and five tributaries from early April through early November, 2007. Constituents reported here include field parameters (water temperature, pH, dissolved oxygen concentration, specific conductance); total nitrogen and phosphorus; particulate carbon and nitrogen; filtered orthophosphate, nitrite, nitrite plus nitrate, ammonia, organic carbon, iron, silica, and alkalinity; specific UV absorbance at 254 nm; phytoplankton and zooplankton enumeration and species identification; and bacterial abundance and morphological subgroups. The ADCP measurements conducted in good weather conditions in May showed that four major canals accounted for most changes in discharge along the mainstem on that day. Direction of velocity at measured locations was fairly homogeneous across the channel, while velocities were generally lowest near the bottom, and highest near surface, ranging from 0.0 to 0.8 ft/s. Measurements in September, made in windy conditions, raised questions about the effect of wind on flow. Most nutrient and carbon concentrations were lowest in spring, increased and remained elevated in summer, and decreased in fall. Dissolved nitrite plus nitrate and nitrite had a different seasonal cycle and were below detection or at low concentration in summer. Many nutrient and

  20. Bathymetric surveys of Morse and Geist Reservoirs in central Indiana made with acoustic Doppler current profiler and global positioning system technology, 1996

    USGS Publications Warehouse

    Wilson, J.T.; Morlock, S.E.; Baker, N.T.

    1997-01-01

    Acoustic Doppler current profiler, global positioning system, and geographic information system technology were used to map the bathymetry of Morse and Geist Reservoirs, two artificial lakes used for public water supply in central Indiana. The project was a pilot study to evaluate the use of the technologies for bathymetric surveys. Bathymetric surveys were last conducted in 1978 on Morse Reservoir and in 1980 on Geist Reservoir; those surveys were done with conventional methods using networks of fathometer transects. The 1996 bathymetric surveys produced updated estimates of reservoir volumes that will serve as base-line data for future estimates of storage capacity and sedimentation rates.An acoustic Doppler current profiler and global positioning system receiver were used to collect water-depth and position data from April 1996 through October 1996. All water-depth and position data were imported to a geographic information system to create a data base. The geographic information system then was used to generate water-depth contour maps and to compute the volumes for each reservoir.The computed volume of Morse Reservoir was 22,820 acre-feet (7.44 billion gallons), with a surface area of 1,484 acres. The computed volume of Geist Reservoir was 19,280 acre-feet (6.29 billion gallons), with a surface area of 1,848 acres. The computed 1996 reservoir volumes are less than the design volumes and indicate that sedimentation has occurred in both reservoirs. Cross sections were constructed from the computer-generated surfaces for 1996 and compared to the fathometer profiles from the 1978 and 1980 surveys; analysis of these cross sections also indicates that some sedimentation has occurred in both reservoirs.The acoustic Doppler current profiler, global positioning system, and geographic information system technologies described in this report produced bathymetric maps and volume estimates more efficiently and with comparable or greater resolution than conventional

  1. Propagation of current pulses with an amplitude of up to 85 kA in soil over distances of several tens of meters

    NASA Astrophysics Data System (ADS)

    Smirnov, V. P.; Fortov, V. E.; Bykov, Yu. A.; Ermolaev, V. A.; Son, E. E.; Bazelyan, E. M.; Skobarikhin, Yu. V.; Grabovski, E. V.; Oleinik, G. M.; Shishlov, A. O.; Gribov, A. N.; Grigor'yants, V. K.; Goryushin, Yu. A.

    2016-02-01

    Conditions for the propagation in soil of current pulses with an amplitude of up to 85 kA and temporal characteristics typical of a lightning stroke are studied with the help of a specially designed mobile test complex on the basis of a 4-MJ capacitive energy storage with an output voltage of up to 2 MV. In contrast to the conventional opinion that the ionization processes in highly conductive soils are weakly pronounced, a dramatic reduction in the grounding resistance at a resistivity of about 100 Ω m and currents above 10 kA was observed. A time interval in which the grounding resistance is determined by the skin effect in soil is revealed. It is shown that the grounding resistance continues to decrease behind the front of the current pulse due to the continuous growth of spark channels in soil. Time variations in the grounding resistance cannot be related to the formation of a continuous ionization zone near the grounding electrodes and are explained only by the simultaneous growth of several long spark channels extending from the grounding device.

  2. Groundwater-Seepage Meter

    NASA Technical Reports Server (NTRS)

    Walthall, Harry G.; Reay, William G.

    1993-01-01

    Instrument measures seepage of groundwater into inland or coastal body of water. Positioned at depth as great as 40 meters, and measures flow at low rate and low pressure differential. Auxiliary pressure meter provides data for correlation of flow of groundwater with tides and sea states. Seepage meter operates independently for several weeks. Its sampling rate adjusted to suit hydrologic conditions; to measure more frequently when conditions changing rapidly. Used in water-quality management and for biological and geological research. Potential industrial uses include measurement of seepage of caustic and corrosive liquids.

  3. Space Age Meter.

    ERIC Educational Resources Information Center

    Phillips, Julie

    1983-01-01

    Discusses the history and evolution of measurement standards from 3000 BC to the modern metric system. Traces measurement techniques from comparisons with the human body to use of atomic clocks and lasers to establish the length of a meter. (JM)

  4. Peak flow meter (image)

    MedlinePlus

    A peak flow meter is commonly used by a person with asthma to measure the amount of air that can be ... become narrow or blocked due to asthma, peak flow values will drop because the person cannot blow ...

  5. Ride-Quality Meter

    NASA Technical Reports Server (NTRS)

    Leatherwood, J. D.; Dempsey, T. K.; Clevenson, S. A.; Stephens, D. G.

    1983-01-01

    Single- and combined-Axis discomfort are corrected by effects of noise and vibration to yield measure of total discomfort experienced by rider. Three modules transform mathematically-weighted rms accelerations, which represent physical vibration characteristics, into subjective discomfort units. Portable "ride-quality" meter measures passenger discomfort and acceptability of vehicle interior noise and vibration. Meter especially suited for determining vehicle comfort and design tradeoffs and for comparing ride quality of vehicles.

  6. DIGITAL Q METER

    DOEpatents

    Briscoe, W.L.

    1962-02-13

    A digital Q meter is described for measuring the Q of mechanical or electrical devices. The meter comprises in combination a transducer coupled to an input amplifier, and an upper and lower level discriminator coupled to the amplifier and having their outputs coupled to an anticoincidence gate. The output of the gate is connected to a scaler. The lower level discriminator is adjusted to a threshold level of 36.8 percent of the operating threshold level of the upper level discriminator. (AEC)

  7. Arrival Metering Precision Study

    NASA Technical Reports Server (NTRS)

    Prevot, Thomas; Mercer, Joey; Homola, Jeffrey; Hunt, Sarah; Gomez, Ashley; Bienert, Nancy; Omar, Faisal; Kraut, Joshua; Brasil, Connie; Wu, Minghong, G.

    2015-01-01

    This paper describes the background, method and results of the Arrival Metering Precision Study (AMPS) conducted in the Airspace Operations Laboratory at NASA Ames Research Center in May 2014. The simulation study measured delivery accuracy, flight efficiency, controller workload, and acceptability of time-based metering operations to a meter fix at the terminal area boundary for different resolution levels of metering delay times displayed to the air traffic controllers and different levels of airspeed information made available to the Time-Based Flow Management (TBFM) system computing the delay. The results show that the resolution of the delay countdown timer (DCT) on the controllers display has a significant impact on the delivery accuracy at the meter fix. Using the 10 seconds rounded and 1 minute rounded DCT resolutions resulted in more accurate delivery than 1 minute truncated and were preferred by the controllers. Using the speeds the controllers entered into the fourth line of the data tag to update the delay computation in TBFM in high and low altitude sectors increased air traffic control efficiency and reduced fuel burn for arriving aircraft during time based metering.

  8. Estimation of Acoustic Particle Motion and Source Bearing Using a Drifting Hydrophone Array Near a River Current Turbine to Assess Disturbances to Fish

    NASA Astrophysics Data System (ADS)

    Murphy, Paul G.

    River hydrokinetic turbines may be an economical alternative to traditional energy sources for small communities on Alaskan rivers. However, there is concern that sound from these turbines could affect sockeye salmon (Oncorhynchus nerka), an important resource for small, subsistence based communities, commercial fisherman, and recreational anglers. The hearing sensitivity of sockeye salmon has not been quantified, but behavioral responses to sounds at frequencies less than a few hundred Hertz have been documented for Atlantic salmon (Salmo salar), and particle motion is thought to be the primary mode of stimulation. Methods of measuring acoustic particle motion are well-established, but have rarely been necessary in energetic areas, such as river and tidal current environments. In this study, the acoustic pressure in the vicinity of an operating river current turbine is measured using a freely drifting hydrophone array. Analysis of turbine sound reveals tones that vary in frequency and magnitude with turbine rotation rate, and that may sockeye salmon may sense. In addition to pressure, the vertical components of particle acceleration and velocity are estimated by calculating the finite difference of the pressure signals from the hydrophone array. A method of determining source bearing using an array of hydrophones is explored. The benefits and challenges of deploying drifting hydrophone arrays for marine renewable energy converter monitoring are discussed.

  9. Long-term ferry-based observations of the suspended sediment fluxes through the Marsdiep inlet using acoustic Doppler current profilers

    NASA Astrophysics Data System (ADS)

    Nauw, J. J.; Merckelbach, L. M.; Ridderinkhof, H.; van Aken, H. M.

    2014-03-01

    Long-term measurements with a hull mounted acoustic Doppler current profiler (ADCP) under the ferry, crossing the Marsdiep inlet between the mainland and the island of Texel (the Netherlands), were used to determine the volume flux and the flux of suspended particulate matter (SPM) through this inlet for the period 2003-2005. Profiles of the SPM concentration were estimated from profiles of the acoustic backscatter intensity in which the shift between the low and the high turbulent regime is taken into account. Calibration constants and tuning parameters were estimated by using data collected during 7 different 13 hour anchor stations. The residual (water) volume flux through the inlet appears to vary strongly on a variety of time scales from daily to inter-annual. A regression analysis indicates that the daily residual volume transport correlates well with the daily mean wind component from the south; the latter likely drives the residual flow along the coast of Holland. The observed residual SPM transport of 7 to 11 Mton/yr is dominated by the correlation between tidal velocity and SPM concentration variations. This leads to an import as currents and SPM concentrations during flood were higher than those during ebb, a process generally known as tidal asymmetry. Our analysis has shown that regular observations with a ferry mounted ADCP is an effective method to monitor the volume and SPM transport processes in an estuary.

  10. Computer and laboratory modeling of radiation-acoustic detector for charged particles pulse beams and plasma parameters measuring

    SciTech Connect

    Kresnin, Yu.A.; Stervoedov, N.G.

    1996-12-31

    Model investigations and laboratory tests of detectors for charged particles pulse beams and plasma parameters measuring are presented. Detector represents combination of classic Faraday cup with electrical way of signal getting and radiation-acoustic meter of pulse beams parameters. Radiation-acoustic meter consists of two parts--thin detector, transparent for beams of high energy particles, and thick detector with full absorption. Ultrasonic oscillations, which arise during interaction of charged particles pulse beams or plasma with detector material, are transformed by piezoelectric detector into electric signals, whose amplitude-frequency and time characteristics functionally depended on beams parameters. All the signals come into microcontroller device Intel MSC51. This device produces calculations of following beam parameters: average energy, pulse charge, pulse currents, density, beam size and pulse time. Calculated characteristics of meter well coincide with experimental measurements, carried out at accelerators in particles energy range from 1 to 100 Mev.

  11. Neutron dose equivalent meter

    DOEpatents

    Olsher, Richard H.; Hsu, Hsiao-Hua; Casson, William H.; Vasilik, Dennis G.; Kleck, Jeffrey H.; Beverding, Anthony

    1996-01-01

    A neutron dose equivalent detector for measuring neutron dose capable of accurately responding to neutron energies according to published fluence to dose curves. The neutron dose equivalent meter has an inner sphere of polyethylene, with a middle shell overlying the inner sphere, the middle shell comprising RTV.RTM. silicone (organosiloxane) loaded with boron. An outer shell overlies the middle shell and comprises polyethylene loaded with tungsten. The neutron dose equivalent meter defines a channel through the outer shell, the middle shell, and the inner sphere for accepting a neutron counter tube. The outer shell is loaded with tungsten to provide neutron generation, increasing the neutron dose equivalent meter's response sensitivity above 8 MeV.

  12. Vector Acoustic Sensors for Marine Seismic Surveys

    NASA Astrophysics Data System (ADS)

    Lindwall, D.

    2005-12-01

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

  13. Transformer and Meter Tester

    NASA Technical Reports Server (NTRS)

    Stoms, R. M.

    1984-01-01

    Numerically-controlled 5-axis machine tool uses transformer and meter to determine and indicate whether tool is in home position, but lacks built-in test mode to check them. Tester makes possible test, and repair of components at machine rather then replace them when operation seems suspect.

  14. Elbow mass flow meter

    DOEpatents

    McFarland, Andrew R.; Rodgers, John C.; Ortiz, Carlos A.; Nelson, David C.

    1994-01-01

    Elbow mass flow meter. The present invention includes a combination of an elbow pressure drop generator and a shunt-type mass flow sensor for providing an output which gives the mass flow rate of a gas that is nearly independent of the density of the gas. For air, the output is also approximately independent of humidity.

  15. Rhythmic Meter Munchies

    ERIC Educational Resources Information Center

    Quinn, Ashley

    2005-01-01

    In this article, the author presents an activity which allows students to construct various rhythm patterns in 2/4, 3/4, and 4/4 meter by using M&Ms and pretzels as an extrinsic motivation. Rhythmic notation is a foundation for learning music concepts. Engaging students in representative modules helps them to learn and recognize note values and…

  16. EMMNet: sensor networking for electricity meter monitoring.

    PubMed

    Lin, Zhi-Ting; Zheng, Jie; Ji, Yu-Sheng; Zhao, Bao-Hua; Qu, Yu-Gui; Huang, Xu-Dong; Jiang, Xiu-Fang

    2010-01-01

    Smart sensors are emerging as a promising technology for a large number of application domains. This paper presents a collection of requirements and guidelines that serve as a basis for a general smart sensor architecture to monitor electricity meters. It also presents an electricity meter monitoring network, named EMMNet, comprised of data collectors, data concentrators, hand-held devices, a centralized server, and clients. EMMNet provides long-distance communication capabilities, which make it suitable suitable for complex urban environments. In addition, the operational cost of EMMNet is low, compared with other existing remote meter monitoring systems based on GPRS. A new dynamic tree protocol based on the application requirements which can significantly improve the reliability of the network is also proposed. We are currently conducting tests on five networks and investigating network problems for further improvements. Evaluation results indicate that EMMNet enhances the efficiency and accuracy in the reading, recording, and calibration of electricity meters. PMID:22163551

  17. Using a 1200 kHz workhorse ADCP with mode 12 to measure near bottom mean currents

    USGS Publications Warehouse

    Martini, M.

    2003-01-01

    Using high frequency Acoustic Doppler Current (ADCP) profiling technology, it is possible to make high-resolution measurements of mean current profiles within a few meters of the seabed. In coastal applications, mean current speeds may be 10 cm/s or less, and oscillatory wave currents may exceed 100 cm/s during storm events. To resolve mean flows of 10 cm/s or less under these conditions, accuracies of 1 cm/s or better are desirable.

  18. Digital Receiver Phase Meter

    NASA Technical Reports Server (NTRS)

    Marcin, Martin; Abramovici, Alexander

    2008-01-01

    The software of a commercially available digital radio receiver has been modified to make the receiver function as a two-channel low-noise phase meter. This phase meter is a prototype in the continuing development of a phase meter for a system in which radiofrequency (RF) signals in the two channels would be outputs of a spaceborne heterodyne laser interferometer for detecting gravitational waves. The frequencies of the signals could include a common Doppler-shift component of as much as 15 MHz. The phase meter is required to measure the relative phases of the signals in the two channels at a sampling rate of 10 Hz at a root power spectral density <5 microcycle/(Hz)1/2 and to be capable of determining the power spectral density of the phase difference over the frequency range from 1 mHz to 1 Hz. Such a phase meter could also be used on Earth to perform similar measurements in laser metrology of moving bodies. To illustrate part of the principle of operation of the phase meter, the figure includes a simplified block diagram of a basic singlechannel digital receiver. The input RF signal is first fed to the input terminal of an analog-to-digital converter (ADC). To prevent aliasing errors in the ADC, the sampling rate must be at least twice the input signal frequency. The sampling rate of the ADC is governed by a sampling clock, which also drives a digital local oscillator (DLO), which is a direct digital frequency synthesizer. The DLO produces samples of sine and cosine signals at a programmed tuning frequency. The sine and cosine samples are mixed with (that is, multiplied by) the samples from the ADC, then low-pass filtered to obtain in-phase (I) and quadrature (Q) signal components. A digital signal processor (DSP) computes the ratio between the Q and I components, computes the phase of the RF signal (relative to that of the DLO signal) as the arctangent of this ratio, and then averages successive such phase values over a time interval specified by the user.

  19. Ocean acoustic hurricane classification.

    PubMed

    Wilson, Joshua D; Makris, Nicholas C

    2006-01-01

    Theoretical and empirical evidence are combined to show that underwater acoustic sensing techniques may be valuable for measuring the wind speed and determining the destructive power of a hurricane. This is done by first developing a model for the acoustic intensity and mutual intensity in an ocean waveguide due to a hurricane and then determining the relationship between local wind speed and underwater acoustic intensity. From this it is shown that it should be feasible to accurately measure the local wind speed and classify the destructive power of a hurricane if its eye wall passes directly over a single underwater acoustic sensor. The potential advantages and disadvantages of the proposed acoustic method are weighed against those of currently employed techniques. PMID:16454274

  20. Application of acoustic doppler velocimeters for streamflow measurements

    USGS Publications Warehouse

    Rehmel, M.

    2007-01-01

    The U.S. Geological Survey (USGS) principally has used Price AA and Price pygmy mechanical current meters for measurement of discharge. New technologies have resulted in the introduction of alternatives to the Price meters. One alternative, the FlowTracker acoustic Doppler velocimeter, was designed by SonTek/YSI to make streamflow measurements in wadeable conditions. The device measures a point velocity and can be used with standard midsection method algorithms to compute streamflow. The USGS collected 55 quality-assurance measurements with the FlowTracker at 43 different USGS streamflow-gaging stations across the United States, with mean depths from 0.05to0.67m, mean velocities from 13 to 60 cm/s, and discharges from 0.02 to 12.4m3/s. These measurements were compared with Price mechanical current meter measurements. Analysis of the comparisons shows that the FlowTracker discharges were not statistically different from the Price meter discharges at a 95% confidence level. ?? 2007 ASCE.

  1. Flow metering valve

    DOEpatents

    Blaedel, Kenneth L.

    1985-01-01

    An apparatus for metering fluids at high pressures of about 20,000 to 60,000 psi is disclosed. The apparatus includes first and second plates which are positioned adjacent each other to form a valve chamber. The plates are made of materials which have substantially equal elastic properties. One plate has a planar surface area, and the other a recessed surface area defined by periphery and central lips. When the two plates are positioned in adjacent contacting relationship, a valve chamber is formed between the planar surface area and the recessed surface area. Fluid is introduced into the chamber and exits therefrom when a deformation occurs at positions where they no longer form a valve seat. This permits the metering of fluids at high pressures and at slow variable rates. Fluid then exits from the chamber until an applied external force becomes large enough to bring the valve seats back into contact.

  2. Flow metering valve

    DOEpatents

    Blaedel, K.L.

    1983-11-03

    An apparatus for metering fluids at high pressures of about 20,000 to 60,000 psi is disclosed. The apparatus includes first and second plates which are positioned adjacent each other to form a valve chamber. The plates are made of materials which have substantially equal elastic properties. One plate has a planar surface area, and the other a recessed surface area defined by periphery and central lips. When the two plates are positioned in adjacent contacting relationship, a valve chamber is formed between the planar surface area and the recessed surface area. Fluid is introduced into the chamber and exits therefrom when a deformation occurs at positions where they no longer form a valve seat. This permits the metering of fluids at high pressures and at slow variable rates. Fluid then exits from the chamber until an applied external force becomes large enough to bring the valve seats back into contact.

  3. Simple Schlieren Light Meter

    NASA Technical Reports Server (NTRS)

    Rhodes, David B.; Franke, John M.; Jones, Stephen B.; Leighty, Bradley D.

    1992-01-01

    Simple light-meter circuit used to position knife edge of schlieren optical system to block exactly half light. Enables operator to check quickly position of knife edge between tunnel runs to ascertain whether or not in alignment. Permanent measuring system made part of each schlieren system. If placed in unused area of image plane, or in monitoring beam from mirror knife edge, provides real-time assessment of alignment of schlieren system.

  4. Period meter for reactors

    DOEpatents

    Rusch, Gordon K.

    1976-01-06

    An improved log N amplifier type nuclear reactor period meter with reduced probability for noise-induced scrams is provided. With the reactor at low power levels a sampling circuit is provided to determine the reactor period by measuring the finite change in the amplitude of the log N amplifier output signal for a predetermined time period, while at high power levels, differentiation of the log N amplifier output signal provides an additional measure of the reactor period.

  5. Acoustic Neuroma

    MedlinePlus

    An acoustic neuroma is a benign tumor that develops on the nerve that connects the ear to the brain. ... can press against the brain, becoming life-threatening. Acoustic neuroma can be difficult to diagnose, because the ...

  6. Rainfall and River Currents Retrieved from Microwave Backscatter

    USGS Publications Warehouse

    Plant, W.J.; Keller, W.C.; Hayes, K.; Nystuen, J.; Spicer, K.

    2003-01-01

    The use of CW microwave sensors in yielding information on both river surface velocities and rain rates was discussed. Eight CW microwave sensors were installed at Cowlitz river in Western Washington State in the US. The sensors measured the river surface velocity via Doppler shifts at eight locations across the river. Comparison of the surface velocities derived from the sensors mounted on the bridge with those measured by current meters and acoustic sensors demonstrated good agreement.

  7. Miniature, high efficiency transducers for use in ultrasonic flow meters

    NASA Astrophysics Data System (ADS)

    Saikia, Meghna

    This thesis is concerned with the development of a new type of miniature, high efficiency transducer for use in ultrasonic flow meters. The proposed transducer consists of a thin plate of a suitable piezoelectric material on which an inter-digital transducer is fabricated for the generation and detection of plate acoustic waves. When immersed in a fluid medium, this device can convert energy from plate acoustic waves (PAWs) into bulk acoustic waves (BAWs) and vice versa. It is shown that this mode coupling principle can be used to realize efficient transducers for use in ultrasonic flow meters. This transducer can be mounted flush with the walls of the pipe through which fluid is flowing, resulting in minimal disturbance of fluid flow. A prototype flow cell using these transducers has been designed and fabricated. The characteristics of this device have been measured over water flow rates varying from 0 to 7.5 liters per minute and found to be in good agreement with theory. Another attractive property of the new transducers is that they can be used to realize remotely read, passive, wireless flow meters. Details of methods that can be used to develop this wireless capability are described. The research carried out in this thesis has applications in several other areas such as ultrasonic nondestructive evaluation (NDE), noncontact or air coupled ultrasonics, and for developing wireless capability in a variety of other acoustic wave sensors.

  8. 77 FR 40586 - Draft NIST Interagency Report (NISTIR) 7823, Advanced Metering Infrastructure Smart Meter...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-10

    ... Metering Infrastructure Smart Meter Upgradeability Test Framework; Request for Comments AGENCY: National... Metering Infrastructure Smart Meter Upgradeability Test Framework (Draft NISTIR 7823). This draft document... process for the Advanced Metering Infrastructure (AMI) Smart Meters. The target audience for Draft...

  9. Acoustic Seal

    NASA Technical Reports Server (NTRS)

    Steinetz, Bruce M. (Inventor)

    2006-01-01

    The invention relates to a sealing device having an acoustic resonator. The acoustic resonator is adapted to create acoustic waveforms to generate a sealing pressure barrier blocking fluid flow from a high pressure area to a lower pressure area. The sealing device permits noncontacting sealing operation. The sealing device may include a resonant-macrosonic-synthesis (RMS) resonator.

  10. Acoustic seal

    NASA Technical Reports Server (NTRS)

    Steinetz, Bruce M. (Inventor)

    2006-01-01

    The invention relates to a sealing device having an acoustic resonator. The acoustic resonator is adapted to create acoustic waveforms to generate a sealing pressure barrier blocking fluid flow from a high pressure area to a lower pressure area. The sealing device permits noncontacting sealing operation. The sealing device may include a resonant-macrosonic-synthesis (RMS) resonator.

  11. Temporal characteristics of coherent flow structures generated over alluvial sand dunes, Mississippi River, revealed by acoustic doppler current profiling and multibeam echo sounding

    USGS Publications Warehouse

    Czuba, John A.; Oberg, Kevin A.; Best, Jim L.; Parsons, Daniel R.; Simmons, S. M.; Johnson, K.K.; Malzone, C.

    2009-01-01

    This paper investigates the flow in the lee of a large sand dune located at the confluence of the Mississippi and Missouri Rivers, USA. Stationary profiles collected from an anchored boat using an acoustic Doppler current profiler (ADCP) were georeferenced with data from a real-time kinematic differential global positioning system. A multibeam echo sounder was used to map the bathymetry of the confluence and provided a morphological context for the ADCP measurements. The flow in the lee of a low-angle dune shows good correspondence with current conceptual models of flow over dunes. As expected, quadrant 2 events (upwellings of low-momentum fluid) are associated with high backscatter intensity. Turbulent events generated in the lower lee of a dune near the bed are associated with periods of vortex shedding and wake flapping. Remnant coherent structures that advect over the lower lee of the dune in the upper portion of the water column, have mostly dissipated and contribute little to turbulence intensities. The turbulent events that occupy most of the water column in the upper lee of the dune are associated with periods of wake flapping.

  12. Using Principal Component and Tidal Analysis as a Quality Metric for Detecting Systematic Heading Uncertainty in Long-Term Acoustic Doppler Current Profiler Data

    NASA Astrophysics Data System (ADS)

    Morley, M. G.; Mihaly, S. F.; Dewey, R. K.; Jeffries, M. A.

    2015-12-01

    Ocean Networks Canada (ONC) operates the NEPTUNE and VENUS cabled ocean observatories to collect data on physical, chemical, biological, and geological ocean conditions over multi-year time periods. Researchers can download real-time and historical data from a large variety of instruments to study complex earth and ocean processes from their home laboratories. Ensuring that the users are receiving the most accurate data is a high priority at ONC, requiring quality assurance and quality control (QAQC) procedures to be developed for all data types. While some data types have relatively straightforward QAQC tests, such as scalar data range limits that are based on expected observed values or measurement limits of the instrument, for other data types the QAQC tests are more comprehensive. Long time series of ocean currents from Acoustic Doppler Current Profilers (ADCP), stitched together from multiple deployments over many years is one such data type where systematic data biases are more difficult to identify and correct. Data specialists at ONC are working to quantify systematic compass heading uncertainty in long-term ADCP records at each of the major study sites using the internal compass, remotely operated vehicle bearings, and more analytical tools such as principal component analysis (PCA) to estimate the optimal instrument alignments. In addition to using PCA, some work has been done to estimate the main components of the current at each site using tidal harmonic analysis. This paper describes the key challenges and presents preliminary PCA and tidal analysis approaches used by ONC to improve long-term observatory current measurements.

  13. Note: Ultrasonic liquid flow meter for small pipes.

    PubMed

    Yu, Yang; Zong, Guanghua

    2012-02-01

    An ultrasonic flow meter for small pipes is presented. For metal pipe diameter smaller than 10 mm, clamp-on ultrasonic contrapropagation flow meters may encounter difficulties if cross talk or the short acoustic path contributes to large uncertainty in transit time measurement. Axial inline flow meters can avoid these problems, but they may introduce other problems if the transducer port is not properly positioned. Three types of pipe connecting tees are compared using the computational fluid dynamics (CFD) method. CFD shows the 45° tee has more uniform velocity distribution over the measuring section. A prototype flow meter using the 45° tee was designed and tested. The zero flow experiment shows the flow meter has a maximum of 0.002 m∕s shift over 24 h. The flow meter is calibrated by only 1 meter factor. After calibration, inaccuracy lower than 0.1% of reading was achieved in the laboratory, for a measuring range from 15 to 150 g∕s (0.29 to 2.99 m∕s; Re = 2688 to 26,876). PMID:22380141

  14. Note: Ultrasonic liquid flow meter for small pipes

    NASA Astrophysics Data System (ADS)

    Yu, Yang; Zong, Guanghua

    2012-02-01

    An ultrasonic flow meter for small pipes is presented. For metal pipe diameter smaller than 10 mm, clamp-on ultrasonic contrapropagation flow meters may encounter difficulties if cross talk or the short acoustic path contributes to large uncertainty in transit time measurement. Axial inline flow meters can avoid these problems, but they may introduce other problems if the transducer port is not properly positioned. Three types of pipe connecting tees are compared using the computational fluid dynamics (CFD) method. CFD shows the 45° tee has more uniform velocity distribution over the measuring section. A prototype flow meter using the 45° tee was designed and tested. The zero flow experiment shows the flow meter has a maximum of 0.002 m/s shift over 24 h. The flow meter is calibrated by only 1 meter factor. After calibration, inaccuracy lower than 0.1% of reading was achieved in the laboratory, for a measuring range from 15 to 150 g/s (0.29 to 2.99 m/s; Re = 2688 to 26 876).

  15. Portable wastewater flow meter

    DOEpatents

    Hunter, Robert M.

    1999-02-02

    A portable wastewater flow meter particularly adapted for temporary use at a single location in measuring the rate of liquid flow in a circular entrance conduit of a sewer manhole both under free flow and submerged, open channel conditions and under fill pipe, surcharged conditions, comprising an apparatus having a cylindrical external surface and an inner surface that constricts the flow through the apparatus in such a manner that a relationship exists between (1) the difference between the static pressure head of liquid flowing through the entrance of the apparatus and the static pressure head of liquid flowing through the constriction, and (2) the rate of liquid flow through the apparatus.

  16. Portable wastewater flow meter

    DOEpatents

    Hunter, Robert M.

    1990-01-01

    A portable wastewater flow meter particularly adapted for temporary use at a single location in measuring the rate of liquid flow in a circular entrance conduit of a sewer manhole both under free flow and submerged, open channel conditions and under full pipe, surcharged conditions, comprising an apparatus having a cylindrical external surface and an inner surface that constricts the flow through the apparatus in such a manner that a relationship exists between (1) the difference between the static pressure head of liquid flowing through the entrance of the apparatus and the static pressure head of liquid flowing through the constriction, and (2) the rate of liquid flow through the apparatus.

  17. Direct reading inductance meter

    NASA Technical Reports Server (NTRS)

    Kolby, R. B. (Inventor)

    1977-01-01

    A direct reading inductance meter comprised of a crystal oscillator and an LC tuned oscillator is presented. The oscillators function respectively to generate a reference frequency, f(r), and to generate an initial frequency, f(0), which when mixed produce a difference equal to zero. Upon connecting an inductor of small unknown value in the LC circuit to change its resonant frequency to f(x), a difference frequency (f(r)-f(x)) is produced that is very nearly a linear function of the inductance of the inductor. The difference frequency is measured and displayed on a linear scale in units of inductance.

  18. The in situ passive acoustic measurement of shingle movement under waves and currents: instrument (TOSCA) development and preliminary results

    NASA Astrophysics Data System (ADS)

    Voulgaris, G.; Wilkin, M. P.; Collins, M. B.

    1995-08-01

    An instrumented platform (TOSCA) is described for monitoring coarse-grained sediment transport in high (wave and tidal) energy environments. The system consists of a number of sensors which measure: instantaneous current velocities at three levels; sea surface elevation; and self-generated noise (SGN) caused by intercollision of particles in transit. SGN is related to transport rates, on the basis of laboratory calibration; this, in turn, allows a correlation with simultaneous near-bed shear stress to be established. During the field measurements, PC-based real-time data transmission is realised through the use of a (buoyed) radio telemetry system. TOSCA has been deployed in eastern Christchurch Bay, southern England. Burst data were collected every 2 h, over 10 min, with a sampling frequency of 5 Hz. The data sets obtained permit detailed investigations into near-bed flow structure and shingle movement, on time-scales comparable to those of the turbulence.

  19. Turbine meters for liquid measurement

    SciTech Connect

    Wass, D.J.; Allen, C.R.

    1995-12-01

    Liquid turbine meters operate in response to fundamental engineering principles, Operation with a single moving part produces excellent longevity and reliability. Liquid turbine meters display wide rangeability, high accuracy, excellent repeatability, low pressure drop and moderate cost. Liquid turbine meters may be applied to many different fluids with different physical properties and corrosive tendencies. The marriage of liquid turbine meters to electronic instruments allows instantaneous flow calculations and produces the flexibility to display data, store data, transmit data in the most convenient form. Liquid turbine meters should be the first flow measurement instrument considered for liquid measurement applications.

  20. Plant chlorophyll content meter

    NASA Technical Reports Server (NTRS)

    Spiering, Bruce A. (Inventor); Carter, Gregory A. (Inventor)

    2000-01-01

    A plant chlorophyll content meter is described which collects light reflected from a target plant and separates the collected light into two different wavelength bands. These wavelength bands, or channels, are described as having center wavelengths of 700 nm and 840 nm. The light collected in these two channels are processed using photo detectors and amplifiers. An analog to digital converter is described which provides a digital representation of the level of light collected by the lens and falling within the two channels. A controller provided in the meter device compares the level of light reflected from a target plant with a level of light detected from a light source, such as light reflected by a target having 100% reflectance, or transmitted through a diffusion receptor. The percent of reflection in the two separate wavelength bands from a target plant are compared to provide a ratio which indicates a relative level of plant physiological stress. A method of compensating for electronic drift is described where a sample is taken when a collection lens is covered to prevent light from entering the device. This compensation method allows for a more accurate reading by reducing error contributions due to electronic drift from environmental conditions at the location where a hand-held unit is used.

  1. Acoustic imaging of the passage of turbidity currents and associated hydraulic jumps on underlying cyclic step bedforms. Squamish, BC

    NASA Astrophysics Data System (ADS)

    Hughes Clarke, J. E.

    2013-12-01

    Active channelized turbidity currents have been repeatedly imaged in 60m of water on the Squamish prodelta. Previously in 2011 and 2012, the prodelta has been repetitively surveyed on daily and hourly timescales and is thus known to exhibit trains of bedforms along the channel floors that resemble cyclic steps that migrate upslope intermittently. Beyond the channel mouths, clear turbidity current flows had previously been detected using a seabed mounted ADCP. In order to directly observe the passage of the flow in the channelized section of the prodelta, in June 2013 a vessel was moored using 4 anchors directly above one of the channels. The vessel operated two hull-mounted single beam sonars at 28 and 200 kHz and a multibeam sonar at 95 kHz, all imaging a near stationary point or swath within or across the channel. In addition a 1200 kHz ADCP was suspended 12m above the seabed and two 500 kHz imaging multibeams were suspended 10m above the channel floor. One of the suspended multibeams was oriented facing upslope examining a 150m range, 120 degree, plan view sector of the channel. The second suspended multibeam was oriented downward to derive a ~30m long along-track section over the length of one of the bedforms. A mechanically dipped CTD and optical backscatter probe was lower repeatedly directly into the active flows until it touched the seabed at about one minute periods. Over a period of 5 days, between 1 and 7 discrete flows per day were monitored passing by within one hour of low water. Their head velocities ranged from ~ 0.5 to 2.5m/s and their thicknesses were generally in the 3-5m range. Looking upstream in plan view, the lobate head of the approaching flows could be seen to be constricted to specific talwegs within the channel floor and rise up and over successive cyclic step bedforms. The higher velocity flows exhibit clear turbulent eddies on their upper surface. The duration of the high velocity component of the flow rarely lasted for more than a few

  2. Liquid metal Flow Meter - Final Report

    SciTech Connect

    Andersen, C.; Hoogendoom, S.; Hudson, B.; Prince, J.; Teichert, K.; Wood, J.; Chase, K.

    2007-01-30

    Measuring the flow of liquid metal presents serious challenges. Current commercially-available flow meters use ultrasonic, electromagnetic, and other technologies to measure flow, but are inadequate for liquid metal flow measurement because of the high temperatures required by most liquid metals. As a result of the reactivity and high temperatures of most liquid metals, corrosion and leakage become very serious safety concerns. The purpose of this project is to develop a flow meter for Lockheed Martin that measures the flow rate of molten metal in a conduit.

  3. Acoustic mapping velocimetry

    NASA Astrophysics Data System (ADS)

    Muste, M.; Baranya, S.; Tsubaki, R.; Kim, D.; Ho, H.; Tsai, H.; Law, D.

    2016-05-01

    Knowledge of sediment dynamics in rivers is of great importance for various practical purposes. Despite its high relevance in riverine environment processes, the monitoring of sediment rates remains a major and challenging task for both suspended and bed load estimation. While the measurement of suspended load is currently an active area of testing with nonintrusive technologies (optical and acoustic), bed load measurement does not mark a similar progress. This paper describes an innovative combination of measurement techniques and analysis protocols that establishes the proof-of-concept for a promising technique, labeled herein Acoustic Mapping Velocimetry (AMV). The technique estimates bed load rates in rivers developing bed forms using a nonintrusive measurements approach. The raw information for AMV is collected with acoustic multibeam technology that in turn provides maps of the bathymetry over longitudinal swaths. As long as the acoustic maps can be acquired relatively quickly and the repetition rate for the mapping is commensurate with the movement of the bed forms, successive acoustic maps capture the progression of the bed form movement. Two-dimensional velocity maps associated with the bed form migration are obtained by implementing algorithms typically used in particle image velocimetry to acoustic maps converted in gray-level images. Furthermore, use of the obtained acoustic and velocity maps in conjunction with analytical formulations (e.g., Exner equation) enables estimation of multidirectional bed load rates over the whole imaged area. This paper presents a validation study of the AMV technique using a set of laboratory experiments.

  4. Small-scale field-aligned currents and ionospheric disturbances induced by vertical acoustic resonance during the 2015 eruption of Chile's Calbuco volcano

    NASA Astrophysics Data System (ADS)

    Aoyama, T.; Iyemori, T.; Nakanishi, K.; Nishioka, M.

    2015-12-01

    Wave packet structure of small-scale magnetic fluctuations were observed by SWARM satellites just above the volcano and it's magnetic conjugate point after the eruption of Chile's Calbuco volcano on April 22, 2015. These magnetic fluctuations in low and middle latitudes generated by small-scale field aligned currents (FACs), and have about 10-30 seconds period along the satellites' orbit [Nakanishi et al., 2014] and about 200 (340) seconds temporal scale for meridional (longitudinal) magnetic components [Iyemori et al., 2015]. We also observed ionospheric disturbances and ground geomagnetic fluctuations just after the eruption. The 4-min period oscillations of total electron content (TEC) were observed by GPS receivers near the volcano. The 260 and 215 seconds spectral peaks in D component of ground based geomagnetic observation were found. Such oscillations and spectral peaks didn't exist before the eruption. All of these observations may have the same origin, i.e., vertical acoustic resonance between the ionosphere and the ground. In this presentation, we estimate the propagation velocity of the TEC oscillations and the spatial scale of the disturbance region in the E-layer where the FACs are generated by the ionospheric dynamo.

  5. Application of acoustic-Doppler current profiler and expendable bathythermograph measurements to the study of the velocity structure and transport of the Gulf Stream

    NASA Technical Reports Server (NTRS)

    Joyce, T. M.; Dunworth, J. A.; Schubert, D. M.; Stalcup, M. C.; Barbour, R. L.

    1988-01-01

    The degree to which Acoustic-Doppler Current Profiler (ADCP) and expendable bathythermograph (XBT) data can provide quantitative measurements of the velocity structure and transport of the Gulf Stream is addressed. An algorithm is used to generate salinity from temperature and depth using an historical Temperature/Salinity relation for the NW Atlantic. Results have been simulated using CTD data and comparing real and pseudo salinity files. Errors are typically less than 2 dynamic cm for the upper 800 m out of a total signal of 80 cm (across the Gulf Stream). When combined with ADCP data for a near-surface reference velocity, transport errors in isopycnal layers are less than about 1 Sv (10 to the 6th power cu m/s), as is the difference in total transport for the upper 800 m between real and pseudo data. The method is capable of measuring the real variability of the Gulf Stream, and when combined with altimeter data, can provide estimates of the geoid slope with oceanic errors of a few parts in 10 to the 8th power over horizontal scales of 500 km.

  6. Estimating sea-ice coverage, draft, and velocity in Marguerite Bay (Antarctica) using a subsurface moored upward-looking acoustic Doppler current profiler (ADCP)

    NASA Astrophysics Data System (ADS)

    Hyatt, Jason; Visbeck, Martin; Beardsley, Robert C.; Brechner Owens, W.

    2008-02-01

    A technique for the analysis of data from a subsurface moored upward-looking acoustic Doppler current profiler (ADCP) to determine ice coverage, draft and velocity is presented and applied to data collected in Marguerite Bay on the western Antarctic Peninsula shelf. This method provides sea-ice information when no dedicated upward-looking sonar (ULS) data are available. Ice detection is accomplished using windowed variances of ADCP vertical velocity, vertical error velocity, and surface horizontal speed. ADCP signal correlation and backscatter intensity were poor indicators of the presence of ice at this site. Ice draft is estimated using a combination of ADCP backscatter data, atmospheric and oceanic pressure data, and information about the thermal stratification. This estimate requires corrections to the ADCP-derived range for instrument tilt and sound speed profile. Uncertainties of ±0.20 m during midwinter and ±0.40 m when the base of the surface mixed layer is above the ADCP for ice draft are estimated based on: (a) a Monte Carlo simulation, (b) uncertainty in the sound speed correction, and (c) performance of the zero-draft estimate during times of known open water. Ice velocity is taken as the ADCP horizontal velocity in the depth bin specified by the range estimate.

  7. Radiation dose rate meter

    SciTech Connect

    Kronenberg, S.; Siebentritt, C.R.

    1981-07-28

    A combined dose rate meter and charger unit therefor which does not require the use of batteries but on the other hand produces a charging potential by means of a piezoelectric cylinder which is struck by a manually triggered hammer mechanism. A tubular type electrometer is mounted in a portable housing which additionally includes a geiger-muller (Gm) counter tube and electronic circuitry coupled to the electrometer for providing multi-mode operation. In one mode of operation, an rc circuit of predetermined time constant is connected to a storage capacitor which serves as a timed power source for the gm tube, providing a measurement in terms of dose rate which is indicated by the electrometer. In another mode, the electrometer indicates individual counts.

  8. GAS METERING PUMP

    DOEpatents

    George, C.M.

    1957-12-31

    A liquid piston gas pump is described, capable of pumping minute amounts of gas in accurately measurable quantities. The pump consists of a flanged cylindrical regulating chamber and a mercury filled bellows. Sealed to the ABSTRACTS regulating chamber is a value and having a gas inlet and outlet, the inlet being connected by a helical channel to the bellows. A gravity check valve is in the gas outlet, so the gas passes through the inlet and the helical channel to the bellows where the pumping action as well as the metering is accomplished by the actuation of the mercury filled bellows. The gas then flows through the check valve and outlet to any associated apparatus.

  9. Microwave fluid flow meter

    DOEpatents

    Billeter, Thomas R.; Philipp, Lee D.; Schemmel, Richard R.

    1976-01-01

    A microwave fluid flow meter is described utilizing two spaced microwave sensors positioned along a fluid flow path. Each sensor includes a microwave cavity having a frequency of resonance dependent upon the static pressure of the fluid at the sensor locations. The resonant response of each cavity with respect to a variation in pressure of the monitored fluid is represented by a corresponding electrical output which can be calibrated into a direct pressure reading. The pressure drop between sensor locations is then correlated as a measure of fluid velocity. In the preferred embodiment the individual sensor cavities are strategically positioned outside the path of fluid flow and are designed to resonate in two distinct frequency modes yielding a measure of temperature as well as pressure. The temperature response can then be used in correcting for pressure responses of the microwave cavity encountered due to temperature fluctuations.

  10. Topological Acoustics

    NASA Astrophysics Data System (ADS)

    Yang, Zhaoju; Gao, Fei; Shi, Xihang; Lin, Xiao; Gao, Zhen; Chong, Yidong; Zhang, Baile

    2015-03-01

    The manipulation of acoustic wave propagation in fluids has numerous applications, including some in everyday life. Acoustic technologies frequently develop in tandem with optics, using shared concepts such as waveguiding and metamedia. It is thus noteworthy that an entirely novel class of electromagnetic waves, known as "topological edge states," has recently been demonstrated. These are inspired by the electronic edge states occurring in topological insulators, and possess a striking and technologically promising property: the ability to travel in a single direction along a surface without backscattering, regardless of the existence of defects or disorder. Here, we develop an analogous theory of topological fluid acoustics, and propose a scheme for realizing topological edge states in an acoustic structure containing circulating fluids. The phenomenon of disorder-free one-way sound propagation, which does not occur in ordinary acoustic devices, may have novel applications for acoustic isolators, modulators, and transducers.

  11. Topological acoustics.

    PubMed

    Yang, Zhaoju; Gao, Fei; Shi, Xihang; Lin, Xiao; Gao, Zhen; Chong, Yidong; Zhang, Baile

    2015-03-20

    The manipulation of acoustic wave propagation in fluids has numerous applications, including some in everyday life. Acoustic technologies frequently develop in tandem with optics, using shared concepts such as waveguiding and metamedia. It is thus noteworthy that an entirely novel class of electromagnetic waves, known as "topological edge states," has recently been demonstrated. These are inspired by the electronic edge states occurring in topological insulators, and possess a striking and technologically promising property: the ability to travel in a single direction along a surface without backscattering, regardless of the existence of defects or disorder. Here, we develop an analogous theory of topological fluid acoustics, and propose a scheme for realizing topological edge states in an acoustic structure containing circulating fluids. The phenomenon of disorder-free one-way sound propagation, which does not occur in ordinary acoustic devices, may have novel applications for acoustic isolators, modulators, and transducers. PMID:25839273

  12. Acoustic telemetry.

    SciTech Connect

    Drumheller, Douglas Schaeffer; Kuszmaul, Scott S.

    2003-08-01

    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.

  13. The Early Development of Electronic pH Meters

    ERIC Educational Resources Information Center

    Hines, Wallis G.; de Levie, Robert

    2010-01-01

    A 19-year-old undergraduate at the University of Chicago, Kenneth Goode, in 1921 came up with the idea of an electronic pH meter, worked out some of its initial problems, and set in motion an international scientific effort that culminated in the current, wide availability of electronic pH meters. Except for the replacement of vacuum tubes by…

  14. De Minimis Thresholds for Federal Building Metering Appropriateness

    SciTech Connect

    Henderson, Jordan W.

    2015-03-31

    The U.S. Department of Energy (DOE) is required by statute and Presidential Memorandum to establish guidelines for agencies to meter their Federal buildings for energy (electricity, natural gas, and steam) and water. See 42 U.S.C. § 8253(e). DOE issued guidance in February 2006 on the installation of electric meters in Federal buildings. A recent update to the 2006 guidance accounts for more current metering practices within the Federal Government. The updated metering guidance specifies that all Federal buildings shall be considered “appropriate” for energy or water metering unless identified for potential exclusion. In developing the updated guidance to carry out the statue, Congress also directed DOE to (among other things) establish exclusions from the metering requirements based on the de minimis quantity of energy use of a Federal building, industrial process, or structure. This paper discusses the method used to identify de minimis values.

  15. Acoustic neuroma

    MedlinePlus

    Vestibular schwannoma; Tumor - acoustic; Cerebellopontine angle tumor; Angle tumor ... 177. Battista RA. Gamma knife radiosurgery for vestibular schwannoma. Otolaryngol Clin North Am . 2009;42:635-654. ...

  16. How to use your peak flow meter

    MedlinePlus

    Peak flow meter - how to use; Asthma - peak flow meter; Reactive airway disease - peak flow meter; Bronchial asthma - peak flow meter ... your airways are narrowed and blocked due to asthma, your peak flow values drop. You can check ...

  17. Musical Acoustics

    NASA Astrophysics Data System (ADS)

    Gough, Colin

    This chapter provides an introduction to the physical and psycho-acoustic principles underlying the production and perception of the sounds of musical instruments. The first section introduces generic aspects of musical acoustics and the perception of musical sounds, followed by separate sections on string, wind and percussion instruments.

  18. Acoustic communication by ants

    NASA Astrophysics Data System (ADS)

    Hickling, Robert

    2002-05-01

    Many ant species communicate acoustically by stridulating, i.e., running a scraper over a washboard-like set of ridges. Ants appear to be insensitive to airborne sound. Consequently, myrmecologists have concluded that the stridulatory signals are transmitted through the substrate. This has tended to diminish the importance of acoustic communication, and it is currently believed that ant communication is based almost exclusively on pheromones, with acoustic communication assigned an almost nonexistent role. However, it can be shown that acoustic communication between ants is effective only if the medium is air and not the substrate. How, then, is it possible for ants to appear deaf to airborne sound and yet communicate through the air? An explanation is provided in a paper [R. Hickling and R. L. Brown, ``Analysis of acoustic communication by ants,'' J. Acoust. Soc. Am. 108, 1920-1929 (2000)]. Ants are small relative to the wavelengths they generate. Hence, they create a near field, which is characterized by a major increase in sound velocity (particle velocity of sound) in the vicinity of the source. Hair sensilla on the ants' antennae respond to sound velocity. Thus, ants are able to detect near-field sound from other ants and to exclude extraneous airborne sound.

  19. Wavelength meter having elliptical wedge

    DOEpatents

    Hackel, Richard P.; Feldman, Mark

    1992-01-01

    A wavelength meter is disclosed which can determine the wavelength of a laser beam from a laser source within an accuracy range of two parts in 10.sup.8. The wavelength meter has wedge having an elliptically shaped face to the optical path of the laser source and includes interferometer plates which form a vacuum housing.

  20. Wavelength meter having elliptical wedge

    DOEpatents

    Hackel, R.P.; Feldman, M.

    1992-12-01

    A wavelength meter is disclosed which can determine the wavelength of a laser beam from a laser source within an accuracy range of two parts in 10[sup 8]. The wavelength meter has wedge having an elliptically shaped face to the optical path of the laser source and includes interferometer plates which form a vacuum housing. 7 figs.

  1. The Metering Guide for Managers.

    ERIC Educational Resources Information Center

    Qayoumi, Mohammed H.

    This volume provides a guide to management of utilities metering in educational facilities, especially colleges and universities. Chapter 1 gives an overview of why utility measurement, specifically the metering of energy consumption, is important in facilities management. Chapter 2 defines the basic units of measurement for both electric and…

  2. Acoustic lens-based swimmer's sonar

    NASA Astrophysics Data System (ADS)

    Linnenbrink, Thomas E.; Desilets, Charles S.; Folds, Donald L.; Quick, Marshall K.

    1999-07-01

    A new high resolution imaging sonar is begin developed for use by swimmers to identify objects in turbid water or under low light level conditions. Beam forming for both the transmit and receive functions is performed with acoustic lenses. The acoustic image is focused on an acoustic retina or focal pane. An acoustic video converter converts the acoustic image to an electronic from suitable for display with conventional electronics. The image will be presented to the swimmer as a heads-up display on the face of his or her mask. The system will provide 1 cm resolution in range and cross range from 1-5 meters from the object. A longer range search mode is being explored. Laboratory prototypes of key components have been fabricated and evaluated. Results to date are promising.

  3. Acoustical Characterization of the Columbia River Estuary

    NASA Astrophysics Data System (ADS)

    Reeder, D. B.

    2014-12-01

    Investigations of near-shore and in-shore environments have, rightly, focused on geological, thermodynamic and hydrodynamic parameters. A complementary acoustical characterization of the estuarine environment provides another layer of information to facilitate a more complete understanding of the physical environment. Relatively few acoustical studies have been carried out in rivers, estuaries or other energetic environments; nearly all acoustical work in such environments has been done at high acoustic frequencies—in the 10's and 100's of kHz. To this end, within the context of a larger hydrodynamic field experiment (RIVET II), a small acoustic field experiment was carried out in the Columbia River Estuary (CRE), the acoustic objective of which was to characterize the acoustic environment in the CRE in terms of ambient noise field statistics and acoustic propagation characteristics at low-to-mid-frequencies. Acoustically, the CRE salt wedge consists of two isospeed layers separated by a thin, three-dimensional high-gradient layer. Results demonstrate that (1) this stratification supports ducting of low-angle acoustic energy in the upper layer and the creation of an acoustic shadow zone in the lower layer; (2) the spatiotemporal dynamics of the salt wedge structure during the very energetic flood and ebb tides induce significant variability in the acoustic environment, as well as significant flow noise across the acoustic transducer; and (3) this flow noise correlates to current velocity and complicates acoustical observations at low frequencies.

  4. Balanced Flow Metering and Conditioning: Technology for Fluid Systems

    NASA Technical Reports Server (NTRS)

    Kelley, Anthony R.

    2006-01-01

    Revolutionary new technology that creates balanced conditions across the face of a multi-hole orifice plate has been developed, patented and exclusively licensed for commercialization. This balanced flow technology simultaneously measures mass flow rate, volumetric flow rate, and fluid density with little or no straight pipe run requirements. Initially, the balanced plate was a drop in replacement for a traditional orifice plate, but testing revealed substantially better performance as compared to the orifice plate such as, 10 times better accuracy, 2 times faster (shorter distance) pressure recovery, 15 times less acoustic noise energy generation, and 2.5 times less permanent pressure loss. During 2004 testing at MSFC, testing revealed several configurations of the balanced flow meter that match the accuracy of Venturi meters while having only slightly more permanent pressure loss. However, the balanced meter only requires a 0.25 inch plate and has no upstream or downstream straight pipe requirements. As a fluid conditioning device, the fluid usually reaches fully developed flow within 1 pipe diameter of the balanced conditioning plate. This paper will describe the basic balanced flow metering technology, provide performance details generated by testing to date and provide implementation details along with calculations required for differing degrees of flow metering accuracy.

  5. Room Acoustics

    NASA Astrophysics Data System (ADS)

    Kuttruff, Heinrich; Mommertz, Eckard

    The traditional task of room acoustics is to create or formulate conditions which ensure the best possible propagation of sound in a room from a sound source to a listener. Thus, objects of room acoustics are in particular assembly halls of all kinds, such as auditoria and lecture halls, conference rooms, theaters, concert halls or churches. Already at this point, it has to be pointed out that these conditions essentially depend on the question if speech or music should be transmitted; in the first case, the criterion for transmission quality is good speech intelligibility, in the other case, however, the success of room-acoustical efforts depends on other factors that cannot be quantified that easily, not least it also depends on the hearing habits of the listeners. In any case, absolutely "good acoustics" of a room do not exist.

  6. Acoustic Neuroma

    MedlinePlus

    ... slow growing tumor which arise primarily from the vestibular portion of the VIII cranial nerve and lie ... you have a "brain tumor" called acoustic neuroma (vestibular schwannoma). You think you are the only one ...

  7. Underwater Acoustics

    NASA Astrophysics Data System (ADS)

    Kuperman, William A.; Roux, Philippe

    It is well underwater established that sound waves, compared to electromagnetic waves, propagate long distances in the ocean. Hence, in the ocean as opposed to air or a vacuum, one uses sound navigation and ranging (SONAR) instead navigation and ranging (SONAR) of radar, acoustic communication instead of radio, and acoustic imaging and tomography instead of microwave or optical imaging or X-ray tomography. Underwater acoustics is the science of sound in water (most commonly in the ocean) and encompasses not only the study of sound propagation, but also the masking of sound signals by interfering phenomenon and signal processing for extracting these signals from interference. This chapter we will present the basics physics of ocean acoustics and then discuss applications.

  8. Strong acoustic wave action

    NASA Astrophysics Data System (ADS)

    Gokhberg, M. B.

    1983-07-01

    Experiments devoted to acoustic action on the atmosphere-magnetosphere-ionosphere system using ground based strong explosions are reviewed. The propagation of acoustic waves was observed by ground observations over 2000 km in horizontal direction and to an altitude of 200 km. Magnetic variations up to 100 nT were detected by ARIEL-3 satellite near the epicenter of the explosion connected with the formation of strong field aligned currents in the magnetosphere. The enhancement of VLF emission at 800 km altitude is observed.

  9. What's a Peak Flow Meter?

    MedlinePlus

    ... KidsHealth in the Classroom What Other Parents Are Reading Upsetting News Reports? What to Say Vaccines: Which ... the meter reads (this is known as a reading). Repeat three times and note the highest recorded ...

  10. Angular velocity and acceleration meter

    NASA Technical Reports Server (NTRS)

    Melamed, L.

    1972-01-01

    Meter uses a liquid crystalline film which changes coloration due to shear-stresses produced by a rotating disk. Device is advantageous in that it is not subject to bearing failure or electrical burnouts as are conventional devices.

  11. Healthcare Energy Metering Guidance (Brochure)

    SciTech Connect

    Not Available

    2011-07-01

    This brochure is intended to help facility and energy managers plan and prioritize investments in energy metering. It offers healthcare-specific examples of metering applications, benefits, and steps that other health systems can reproduce. It reflects collaborative input from the U.S. Department of Energy national laboratories and the health system members of the DOE Hospital Energy Alliance's Benchmarking and Measurement Project Team.

  12. Micro acoustic spectrum analyzer

    DOEpatents

    Schubert, W. Kent; Butler, Michael A.; Adkins, Douglas R.; Anderson, Larry F.

    2004-11-23

    A micro acoustic spectrum analyzer for determining the frequency components of a fluctuating sound signal comprises a microphone to pick up the fluctuating sound signal and produce an alternating current electrical signal; at least one microfabricated resonator, each resonator having a different resonant frequency, that vibrate in response to the alternating current electrical signal; and at least one detector to detect the vibration of the microfabricated resonators. The micro acoustic spectrum analyzer can further comprise a mixer to mix a reference signal with the alternating current electrical signal from the microphone to shift the frequency spectrum to a frequency range that is a better matched to the resonant frequencies of the microfabricated resonators. The micro acoustic spectrum analyzer can be designed specifically for portability, size, cost, accuracy, speed, power requirements, and use in a harsh environment. The micro acoustic spectrum analyzer is particularly suited for applications where size, accessibility, and power requirements are limited, such as the monitoring of industrial equipment and processes, detection of security intrusions, or evaluation of military threats.

  13. Energy Theft in the Advanced Metering Infrastructure

    NASA Astrophysics Data System (ADS)

    McLaughlin, Stephen; Podkuiko, Dmitry; McDaniel, Patrick

    Global energy generation and delivery systems are transitioning to a new computerized "smart grid". One of the principle components of the smart grid is an advanced metering infrastructure (AMI). AMI replaces the analog meters with computerized systems that report usage over digital communication interfaces, e.g., phone lines. However, with this infrastructure comes new risk. In this paper, we consider adversary means of defrauding the electrical grid by manipulating AMI systems. We document the methods adversaries will use to attempt to manipulate energy usage data, and validate the viability of these attacks by performing penetration testing on commodity devices. Through these activities, we demonstrate that not only is theft still possible in AMI systems, but that current AMI devices introduce a myriad of new vectors for achieving it.

  14. NW-MILO Acoustic Data Collection

    SciTech Connect

    Matzner, Shari; Myers, Joshua R.; Maxwell, Adam R.; Jones, Mark E.

    2010-02-17

    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

  15. Secure Metering Schemes

    NASA Astrophysics Data System (ADS)

    Blundo, Carlo; Cimato, Stelvio; Masucci, Barbara

    The current trend on the Internet suggests that the majority of revenues of web sites come from the advertising potential of the World Wide Web. Advertising is arguably the type of commercial information exchange of the greatest economic importance in the real world. Indeed, advertising is what funds most other forms of information exchange, including radio stations, television stations, cable networks, magazines, and newspapers. According to the figures provided by the Internet Advertising Bureau [24] and Price Waterhouse Coopers [43], advertising revenue results for the first 9 months of 2004 totaled slightly over 7.0 billion dollars.

  16. Status of Net Metering: Assessing the Potential to Reach Program Caps

    SciTech Connect

    Heeter, J.; Gelman, R.; Bird, L.

    2014-09-01

    Several states are addressing the issue of net metering program caps, which limit the total amount of net metered generating capacity that can be installed in a state or utility service territory. In this analysis, we examine net metering caps to gain perspective on how long net metering will be available in various jurisdictions under current policies. We also surveyed state practices and experience to understand important policy design considerations.

  17. Status of Net Metering: Assessing the Potential to Reach Program Caps (Poster)

    SciTech Connect

    Heeter, J.; Bird, L.; Gelman, R.

    2014-10-01

    Several states are addressing the issue of net metering program caps, which limit the total amount of net metered generating capacity that can be installed in a state or utility service territory. In this analysis, we examine net metering caps to gain perspective on how long net metering will be available in various jurisdictions under current policies. We also surveyed state practices and experience to understand important policy design considerations.

  18. Insert metering plates for gas turbine nozzles

    DOEpatents

    Burdgick, Steven S.; Itzel, Gary; Chopra, Sanjay; Abuaf, Nesim; Correia, Victor H.

    2004-05-11

    The invention comprises a metering plate which is assembled to an impingement insert for use in the nozzle of a gas turbine. The metering plate can have one or more metering holes and is used to balance the cooling flow within the nozzle. A metering plate with multiple holes reduces static pressure variations which result from the cooling airflow through the metering plate. The metering plate can be assembled to the insert before or after the insert is inserted into the nozzle.

  19. Acoustic biosensors

    PubMed Central

    Fogel, Ronen; Seshia, Ashwin A.

    2016-01-01

    Resonant and acoustic wave devices have been researched for several decades for application in the gravimetric sensing of a variety of biological and chemical analytes. These devices operate by coupling the measurand (e.g. analyte adsorption) as a modulation in the physical properties of the acoustic wave (e.g. resonant frequency, acoustic velocity, dissipation) that can then be correlated with the amount of adsorbed analyte. These devices can also be miniaturized with advantages in terms of cost, size and scalability, as well as potential additional features including integration with microfluidics and electronics, scaled sensitivities associated with smaller dimensions and higher operational frequencies, the ability to multiplex detection across arrays of hundreds of devices embedded in a single chip, increased throughput and the ability to interrogate a wider range of modes including within the same device. Additionally, device fabrication is often compatible with semiconductor volume batch manufacturing techniques enabling cost scalability and a high degree of precision and reproducibility in the manufacturing process. Integration with microfluidics handling also enables suitable sample pre-processing/separation/purification/amplification steps that could improve selectivity and the overall signal-to-noise ratio. Three device types are reviewed here: (i) bulk acoustic wave sensors, (ii) surface acoustic wave sensors, and (iii) micro/nano-electromechanical system (MEMS/NEMS) sensors. PMID:27365040

  20. Acoustic biosensors.

    PubMed

    Fogel, Ronen; Limson, Janice; Seshia, Ashwin A

    2016-06-30

    Resonant and acoustic wave devices have been researched for several decades for application in the gravimetric sensing of a variety of biological and chemical analytes. These devices operate by coupling the measurand (e.g. analyte adsorption) as a modulation in the physical properties of the acoustic wave (e.g. resonant frequency, acoustic velocity, dissipation) that can then be correlated with the amount of adsorbed analyte. These devices can also be miniaturized with advantages in terms of cost, size and scalability, as well as potential additional features including integration with microfluidics and electronics, scaled sensitivities associated with smaller dimensions and higher operational frequencies, the ability to multiplex detection across arrays of hundreds of devices embedded in a single chip, increased throughput and the ability to interrogate a wider range of modes including within the same device. Additionally, device fabrication is often compatible with semiconductor volume batch manufacturing techniques enabling cost scalability and a high degree of precision and reproducibility in the manufacturing process. Integration with microfluidics handling also enables suitable sample pre-processing/separation/purification/amplification steps that could improve selectivity and the overall signal-to-noise ratio. Three device types are reviewed here: (i) bulk acoustic wave sensors, (ii) surface acoustic wave sensors, and (iii) micro/nano-electromechanical system (MEMS/NEMS) sensors. PMID:27365040

  1. Method of Adjusting Acoustic Impedances for Impedance-Tunable Acoustic Segments

    NASA Technical Reports Server (NTRS)

    Jones, Kennie H (Inventor); Nark, Douglas M. (Inventor); Jones, Michael G. (Inventor); Parrott, Tony L. (Inventor); Lodding, Kenneth N. (Inventor)

    2012-01-01

    A method is provided for making localized decisions and taking localized actions to achieve a global solution. In an embodiment of the present invention, acoustic impedances for impedance-tunable acoustic segments are adjusted. A first acoustic segment through an N-th acoustic segment are defined. To start the process, the first acoustic segment is designated as a leader and a noise-reducing impedance is determined therefor. This is accomplished using (i) one or more metrics associated with the acoustic wave at the leader, and (ii) the metric(s) associated with the acoustic wave at the N-th acoustic segment. The leader, the N-th acoustic segment, and each of the acoustic segments exclusive of the leader and the N-th acoustic segment, are tuned to the noise-reducing impedance. The current leader is then excluded from subsequent processing steps. The designation of leader is then given one of the remaining acoustic segments, and the process is repeated for each of the acoustic segments through an (N-1)-th one of the acoustic segments.

  2. Arduino based radiation survey meter

    NASA Astrophysics Data System (ADS)

    Rahman, Nur Aira Abd; Lombigit, Lojius; Abdullah, Nor Arymaswati; Azman, Azraf; Dolah, Taufik; Muzakkir, Amir; Jaafar, Zainudin; Mohamad, Glam Hadzir Patai; Ramli, Abd Aziz Mhd; Zain, Rasif Mohd; Said, Fazila; Khalid, Mohd Ashhar; Taat, Muhamad Zahidee

    2016-01-01

    This paper presents the design of new digital radiation survey meter with LND7121 Geiger Muller tube detector and Atmega328P microcontroller. Development of the survey meter prototype is carried out on Arduino Uno platform. 16-bit Timer1 on the microcontroller is utilized as external pulse counter to produce count per second or CPS measurement. Conversion from CPS to dose rate technique is also performed by Arduino to display results in micro Sievert per hour (μSvhr-1). Conversion factor (CF) value for conversion of CPM to μSvhr-1 determined from manufacturer data sheet is compared with CF obtained from calibration procedure. The survey meter measurement results are found to be linear for dose rates below 3500 µSv/hr.

  3. Low Cost Digital Vibration Meter

    PubMed Central

    Payne, W. Vance; Geist, Jon

    2007-01-01

    This report describes the development of a low cost, digital Micro Electro Mechanical System (MEMS) vibration meter that reports an approximation to the RMS acceleration of the vibration to which the vibration meter is subjected. The major mechanical element of this vibration meter is a cantilever beam, which is on the order of 500 µm in length, with a piezoresistor deposited at its base. Vibration of the device in the plane perpendicular to the cantilever beam causes it to bend, which produces a measurable change in the resistance of a piezoresistor. These changes in resistance along with a unique signal-processing scheme are used to determine an approximation to the RMS acceleration sensed by the device. PMID:27110459

  4. Dance, Music, Meter and Groove: A Forgotten Partnership.

    PubMed

    Fitch, W Tecumseh

    2016-01-01

    I argue that core aspects of musical rhythm, especially "groove" and syncopation, can only be fully understood in the context of their origins in the participatory social experience of dance. Musical meter is first considered in the context of bodily movement. I then offer an interpretation of the pervasive but somewhat puzzling phenomenon of syncopation in terms of acoustic emphasis on certain offbeat components of the accompanying dance style. The reasons for the historical tendency of many musical styles to divorce themselves from their dance-based roots are also briefly considered. To the extent that musical rhythms only make sense in the context of bodily movement, researchers interested in ecologically valid approaches to music cognition should make a more concerted effort to extend their analyses to dance, particularly if we hope to understand the cognitive constraints underlying rhythmic aspects of music like meter and groove. PMID:26973489

  5. Dance, Music, Meter and Groove: A Forgotten Partnership

    PubMed Central

    Fitch, W. Tecumseh

    2016-01-01

    I argue that core aspects of musical rhythm, especially “groove” and syncopation, can only be fully understood in the context of their origins in the participatory social experience of dance. Musical meter is first considered in the context of bodily movement. I then offer an interpretation of the pervasive but somewhat puzzling phenomenon of syncopation in terms of acoustic emphasis on certain offbeat components of the accompanying dance style. The reasons for the historical tendency of many musical styles to divorce themselves from their dance-based roots are also briefly considered. To the extent that musical rhythms only make sense in the context of bodily movement, researchers interested in ecologically valid approaches to music cognition should make a more concerted effort to extend their analyses to dance, particularly if we hope to understand the cognitive constraints underlying rhythmic aspects of music like meter and groove. PMID:26973489

  6. Operating experience using venturi flow meters at liquid helium temperature

    SciTech Connect

    Wu, K.C.

    1992-06-01

    Experiences using commercial venturi to measure single phase helium flow near 4 K (degree Kelvin) for cooling superconducting magnets have been presented. The mass flow rate was calculated from the differential pressure and the helium density evaluated from measured pressure and temperature. The venturi flow meter, with a full range of 290 g/s (0.29 Kg/s) at design conditions, has been found to be reliable and accurate. The flow measurements have been used, with great success, for evaluating the performance of a cold centrifugal compressor, the thermal acoustic heat load of a cryogenic system and the cooling of a superconducting magnet after quench.

  7. Operating experience using venturi flow meters at liquid helium temperature

    SciTech Connect

    Wu, K.C.

    1992-01-01

    Experiences using commercial venturi to measure single phase helium flow near 4 K (degree Kelvin) for cooling superconducting magnets have been presented. The mass flow rate was calculated from the differential pressure and the helium density evaluated from measured pressure and temperature. The venturi flow meter, with a full range of 290 g/s (0.29 Kg/s) at design conditions, has been found to be reliable and accurate. The flow measurements have been used, with great success, for evaluating the performance of a cold centrifugal compressor, the thermal acoustic heat load of a cryogenic system and the cooling of a superconducting magnet after quench.

  8. Justification of the Utility of Introducing Smart Meters in Latvia

    NASA Astrophysics Data System (ADS)

    Kunickis, M.; Dandens, A.; Bariss, U.

    2015-12-01

    Automatic data reading from smart meters is being developed in many parts of the world, including Latvia. The key drivers for that are developments of smart technologies and economic benefits for consumers. Deployment of smart meters could be launched in a massive scale. Several pilot projects were implemented to verify the feasibility of smart meters for individual consumer groups. Preliminary calculations indicate that installation of smart meters for approximately 23 % of electricity consumers would be economically viable. Currently, the data for the last two years is available for an in-depth mathematical analysis. The continuous analysis of consumption data would be established, when more measurements from smart meters are available. The extent of introduction of smart meters should be specified during this process in order to gain the maximum benefit for the whole society (consumers, grid companies, state authorities), because there are still many uncertain and variable factors. For example, it is necessary to consider statistical load variations by hour, dependence of electricity consumption on temperature fluctuations, consumer behaviour and demand response to market signals to reduce electricity consumption in the short and long term, consumer's ambitions and capability to install home automation for regulation of electricity consumption. To develop the demand response, it is necessary to analyse the whole array of additional factors, such as expected cost reduction of smart meters, possible extension of their functionality, further development of information exchange systems, as well as standard requirements and different political and regulatory decisions regarding the reduction of electricity consumption and energy efficiency.

  9. EDD-7 Electric Charge Point Meter test results

    SciTech Connect

    Mersman, C.R.

    1993-09-01

    The results of tests evaluating the electric switching portion of the EDD-7 Electric Charge Point Meter (ECPM) are presented. The ECPM is a modified parking meter that allows the purchase of 120 or 240 volt electric power. The ECPM is designed to make electricity available at any vehicle parking location. The test results indicate that the ECPM operated without failure thru a series of over current and ground fault tests at three different test temperatures. The magnitude of current required to trip the over current protection circuitry varied with temperature while the performance of the ground fault interruption circuitry did not change significantly with the test temperature.

  10. EDD-7 Electric Charge Point Meter test results

    NASA Astrophysics Data System (ADS)

    Mersman, C. R.

    1993-09-01

    The results of tests evaluating the electric switching portion of the EDD-7 Electric Charge Point Meter (ECPM) are presented. The ECPM is a modified parking meter that allows the purchase of 120 or 240 volt electric power. The ECPM is designed to make electricity available at any vehicle parking location. The test results indicate that the ECPM operated without failure through a series of over current and ground fault tests at three different test temperatures. The magnitude of current required to trip the over current protection circuitry varied with temperature while the performance of the ground fault interruption circuitry did not change significantly with the test temperature.

  11. Acoustic techniques in nuclear safeguards

    SciTech Connect

    Olinger, C.T.; Sinha, D.N.

    1995-07-01

    Acoustic techniques can be employed to address many questions relevant to current nuclear technology needs. These include establishing and monitoring intrinsic tags and seals, locating holdup in areas where conventional radiation-based measurements have limited capability, process monitoring, monitoring containers for corrosion or changes in pressure, and facility design verification. These acoustics applications are in their infancy with respect to safeguards and nuclear material management, but proof-of-principle has been demonstrated in many of the areas listed.

  12. Intelligent Engine Systems: Acoustics

    NASA Technical Reports Server (NTRS)

    Wojno, John; Martens, Steve; Simpson, Benjamin

    2008-01-01

    An extensive study of new fan exhaust nozzle technologies was performed. Three new uniform chevron nozzles were designed, based on extensive CFD analysis. Two new azimuthally varying variants were defined. All five were tested, along with two existing nozzles, on a representative model-scale, medium BPR exhaust nozzle. Substantial acoustic benefits were obtained from the uniform chevron nozzle designs, the best benefit being provided by an existing design. However, one of the azimuthally varying nozzle designs exhibited even better performance than any of the uniform chevron nozzles. In addition to the fan chevron nozzles, a new technology was demonstrated, using devices that enhance mixing when applied to an exhaust nozzle. The acoustic benefits from these devices applied to medium BPR nozzles were similar, and in some cases superior to, those obtained from conventional uniform chevron nozzles. However, none of the low noise technologies provided equivalent acoustic benefits on a model-scale high BPR exhaust nozzle, similar to current large commercial applications. New technologies must be identified to improve the acoustics of state-of-the-art high BPR jet engines.

  13. Metering technology enters new phase

    SciTech Connect

    Hansen, T.

    1995-08-01

    Automated metering technology (AMT) is emerging from the limited function of automatic meter-reading to collect useful information that can be used to improve customer service and increase profitability. Specifically, AMT: eliminates monthly usage estimating for customers in hard-to-read areas; eliminates meter reading direct labor costs; provides 24-hour-a-day access to residential, industrial and commercial customers, eliminating intrusion on private property; provides the utility with a load (usage) profile for each customer; provides real-time pricing; provides real-time alarms for outages and meter-tampering. In the competitive environment of deregulation, linking utilities and their customers through two-way communications will be one of the keys to offering the kinds of services and products that will differentiate utilities and satisfy customers. Data collected using AMT can be used to develop customer profiles, enabling the utility to offer customized service packages to individual customers. AMT tends to reduce complaints about bills and increase customer satisfaction.

  14. Direct-reading inductance meter

    NASA Technical Reports Server (NTRS)

    Kolbly, R. B.

    1977-01-01

    Meter indicates from 30 nH to 3 micro H. Reference inductor of 15 micro H is made by winding 50 turns of Number 26 Formvar wire on Micrometal type 50-2 (or equivalent) core. Circuit eliminates requirement for complex instrument compensation prior to taking coil inductance measurement and thus is as easy to operate as common ohmmeter.

  15. A Redesigned DFA Moisture Meter

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The DFA moisture meter has been internationally recognized as the standard for determining moisture content of dried fruit in general and is AOAC Official Method 972.2 for measuring moisture in prunes and raisins since 1972. The device has remained virtually unchanged since its inception, with its o...

  16. Acoustic transducer for acoustic microscopy

    DOEpatents

    Khuri-Yakub, Butrus T.; Chou, Ching H.

    1990-01-01

    A shear acoustic transducer-lens system in which a shear polarized piezoelectric material excites shear polarized waves at one end of a buffer rod having a lens at the other end which excites longitudinal waves in a coupling medium by mode conversion at selected locations on the lens.

  17. Acoustic transducer for acoustic microscopy

    DOEpatents

    Khuri-Yakub, B.T.; Chou, C.H.

    1990-03-20

    A shear acoustic transducer-lens system is described in which a shear polarized piezoelectric material excites shear polarized waves at one end of a buffer rod having a lens at the other end which excites longitudinal waves in a coupling medium by mode conversion at selected locations on the lens. 9 figs.

  18. Compensated count-rate circuit for radiation survey meter

    DOEpatents

    Todd, R.A.

    1980-05-12

    A count-rate compensating circuit is provided which may be used in a portable Geiger-Mueller (G-M) survey meter to ideally compensate for couting loss errors in the G-M tube detector. In a G-M survey meter, wherein the pulse rate from the G-M tube is converted into a pulse rate current applied to a current meter calibrated to indicate dose rate, the compensation circuit generates and controls a reference voltage in response to the rate of pulses from the detector. This reference voltage is gated to the current-generating circuit at a rate identical to the rate of pulses coming from the detector so that the current flowing through the meter is varied in accordance with both the frequency and amplitude of the reference voltage pulses applied thereto so that the count rate is compensated ideally to indicate a true count rate within 1% up to a 50% duty cycle for the detector. A positive feedback circuit is used to control the reference voltage so that the meter output tracks true count rate indicative of the radiation dose rate.

  19. Compensated count-rate circuit for radiation survey meter

    DOEpatents

    Todd, Richard A.

    1981-01-01

    A count-rate compensating circuit is provided which may be used in a portable Geiger-Mueller (G-M) survey meter to ideally compensate for counting loss errors in the G-M tube detector. In a G-M survey meter, wherein the pulse rate from the G-M tube is converted into a pulse rate current applied to a current meter calibrated to indicate dose rate, the compensated circuit generates and controls a reference voltage in response to the rate of pulses from the detector. This reference voltage is gated to the current-generating circuit at a rate identical to the rate of pulses coming from the detector so that the current flowing through the meter is varied in accordance with both the frequency and amplitude of the reference voltage pulses applied thereto so that the count rate is compensated ideally to indicate a true count rate within 1% up to a 50% duty cycle for the detector. A positive feedback circuit is used to control the reference voltage so that the meter output tracks true count rate indicative of the radiation dose rate.

  20. Medical Acoustics

    NASA Astrophysics Data System (ADS)

    Beach, Kirk; Dunmire, Barbrina

    Medical acoustics can be subdivided into diagnostics and therapy. Diagnostics are further separated into auditory and ultrasonic methods, and both employ low amplitudes. Therapy (excluding medical advice) uses ultrasound for heating, cooking, permeablizing, activating and fracturing tissues and structures within the body, usually at much higher amplitudes than in diagnostics. Because ultrasound is a wave, linear wave physics are generally applicable, but recently nonlinear effects have become more important, even in low-intensity diagnostic applications.

  1. Acoustic chaos

    SciTech Connect

    Lauterborn, W.; Parlitz, U.; Holzfuss, J.; Billo, A.; Akhatov, I.

    1996-06-01

    Acoustic cavitation, a complex, spatio-temporal dynamical system, is investigated with respect to its chaotic properties. The sound output, the {open_quote}{open_quote}noise{close_quote}{close_quote}, is subjected to time series analysis. The spatial dynamics of the bubble filaments is captured by high speed holographic cinematography and subsequent digital picture processing from the holograms. Theoretical models are put forward for describing the pattern formation. {copyright} {ital 1996 American Institute of Physics.}

  2. Volumetric Imaging Using Acoustical Holography

    NASA Astrophysics Data System (ADS)

    Garlick, T. F.; Garlick, G. F.

    Transmission acoustical holography holds tremendous promise for medical imaging applications. As with optical holography, an image is obtained using the interference of two coherent acoustic sources, the transmitted object wave with a reference wave. Although resultant images are true holograms, depth can be difficult to quantify and an entire volume in one image can often result in "too much" information. Since Physicians/Radiologists are often interested in viewing a single plane at a time, techniques have been developed to generate acoustic holograms of "slices" within a volume. These primarily include focused transmission holography with spatial and frequency filtering techniques. These techniques along with an overview and current status of acoustical holography in medical imaging applications will be presented

  3. Federal Building Metering Guidance (per 42 U.S.C. 8253(e), Metering of Energy Use)

    SciTech Connect

    2014-11-01

    Guidance defines which federal buildings are appropriate to meter, provides metering prioritization recommendations for agencies with limited resources, and discusses the requirement for agencies to submit metering implementation plans to the U.S. Department of Energy.

  4. Government Program Briefing: Smart Metering

    SciTech Connect

    Doris, E.; Peterson, K.

    2011-09-01

    This document is adapted and updated from a memo delivered to the City Council of New Orleans, the office of the Mayor of New Orleans, the Chairperson of the Citizen Stakeholders Group (New Orleans Energy Task Force) and the U.S. Department of Energy (DOE) Project Officer in March 2008. This briefing piece provides an overview of the benefits, costs, and challenges of smart metering.

  5. A color sensor wavelength meter

    NASA Astrophysics Data System (ADS)

    Durfee, Dallin; Jackson, Jarom; Otterstrom, Nils; Jones, Tyler; Archibald, James

    2016-05-01

    We will discuss a laser wavelength meter based on a commercial color sensor chip consisting of an array of photodiodes with different absorptive color filters. By comparing the relative amplitudes of light on the photodiodes, the wavelength of light can be determined with picometer-level precision and with picometer-scale calibration drift over a period longer than a month. This work was supported by NSF Grant Number PHY-1205736.

  6. Acoustically Enhanced Electroplating Being Developed

    NASA Technical Reports Server (NTRS)

    Oeftering, Richard C.

    2002-01-01

    In cooperation with the NASA Glenn Research Center, Alchemitron Corp. is developing the Acoustically Enhanced Electroplating Process (AEEP), a new technique of employing nonlinear ultrasonics to enhance electroplating. The applications range from electroplating full-panel electronic circuit boards to electroplating microelectronics and microelectromechanical systems (MEMS) devices. In a conventional plating process, the surface area to be plated is separated from the nonplated areas by a temporary mask. The mask may take many forms, from a cured liquid coating to a simple tape. Generally, the mask is discarded when the plating is complete, creating a solid waste product that is often an environmental hazard. The labor and materials involved with the layout, fabrication, and tooling of masks is a primary source of recurring and nonrecurring production costs. The objective of this joint effort, therefore, is to reduce or eliminate the need for masks. AEEP improves selective plating processes by using directed beams of high-intensity acoustic waves to create nonlinear effects that alter the fluid dynamic and thermodynamic behavior of the plating process. It relies on two effects: acoustic streaming and acoustic heating. Acoustic streaming is observed when a high-intensity acoustic beam creates a liquid current within the beam. The liquid current can be directed as the beam is directed and, thus, users can move liquid around as desired without using pumps and nozzles. The current of the electroplating electrolyte, therefore, can be directed at distinct target areas where electroplating is desired. The current delivers fresh electrolyte to the target area while flushing away the spent electrolyte. This dramatically increases the plating rate in the target area. In addition, acoustic heating of both the liquid in the beam and the target surface increases the chemical reaction rate, which further increases the plating rate. The combined effects of acoustic streaming and

  7. Acoustic Tooth Cleaner

    NASA Technical Reports Server (NTRS)

    Heyman, J. S.

    1984-01-01

    Acoustically-energized water jet aids in plaque breakdown. Acoustic Wand includes acoustic transducer 1/4 wave plate, and tapered cone. Together elements energize solution of water containing mild abrasive injected into mouth to help prevent calculous buildup.

  8. NUCLEAR MIXING METERS FOR CLASSICAL NOVAE

    SciTech Connect

    Kelly, Keegan J.; Iliadis, Christian; Downen, Lori; Champagne, Art; José, Jordi

    2013-11-10

    Classical novae are caused by mass transfer episodes from a main-sequence star onto a white dwarf via Roche lobe overflow. This material possesses angular momentum and forms an accretion disk around the white dwarf. Ultimately, a fraction of this material spirals in and piles up on the white dwarf surface under electron-degenerate conditions. The subsequently occurring thermonuclear runaway reaches hundreds of megakelvin and explosively ejects matter into the interstellar medium. The exact peak temperature strongly depends on the underlying white dwarf mass, the accreted mass and metallicity, and the initial white dwarf luminosity. Observations of elemental abundance enrichments in these classical nova events imply that the ejected matter consists not only of processed solar material from the main-sequence partner but also of material from the outer layers of the underlying white dwarf. This indicates that white dwarf and accreted matter mix prior to the thermonuclear runaway. The processes by which this mixing occurs require further investigation to be understood. In this work, we analyze elemental abundances ejected from hydrodynamic nova models in search of elemental abundance ratios that are useful indicators of the total amount of mixing. We identify the abundance ratios ΣCNO/H, Ne/H, Mg/H, Al/H, and Si/H as useful mixing meters in ONe novae. The impact of thermonuclear reaction rate uncertainties on the mixing meters is investigated using Monte Carlo post-processing network calculations with temperature-density evolutions of all mass zones computed by the hydrodynamic models. We find that the current uncertainties in the {sup 30}P(p, γ){sup 31}S rate influence the Si/H abundance ratio, but overall the mixing meters found here are robust against nuclear physics uncertainties. A comparison of our results with observations of ONe novae provides strong constraints for classical nova models.

  9. Wireless Multiplexed Surface Acoustic Wave Sensors Project

    NASA Technical Reports Server (NTRS)

    Youngquist, Robert C.

    2014-01-01

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

  10. Cetacean Acoustics

    NASA Astrophysics Data System (ADS)

    Au, Whitlow W. L.; Lammers, Marc O.

    The mammalian order cetacea consist of dolphins and whales, animals that are found in all the oceans and seas of the world. A few species even inhabit fresh water lakes and rivers. A list of 80 species of cetaceans in a convenient table is presented by Ridgway [20.1]. These mammals vary considerably in size, from the largest living mammal, the large blue whale (balaenoptera musculus), to the very small harbor porpoise (phocoena phocoena) and Commerson's dolphin (cephalorhynchus commersonnii), which are typically slightly over a meter in length.

  11. 1-Meter Digital Elevation Model specification

    USGS Publications Warehouse

    Arundel, Samantha T.; Archuleta, Christy-Ann M.; Phillips, Lori A.; Roche, Brittany L.; Constance, Eric W.

    2015-01-01

    In January 2015, the U.S. Geological Survey National Geospatial Technical Operations Center began producing the 1-Meter Digital Elevation Model data product. This new product was developed to provide high resolution bare-earth digital elevation models from light detection and ranging (lidar) elevation data and other elevation data collected over the conterminous United States (lower 48 States), Hawaii, and potentially Alaska and the U.S. territories. The 1-Meter Digital Elevation Model consists of hydroflattened, topographic bare-earth raster digital elevation models, with a 1-meter x 1-meter cell size, and is available in 10,000-meter x 10,000-meter square blocks with a 6-meter overlap. This report details the specifications required for the production of the 1-Meter Digital Elevation Model.

  12. Cross-cultural differences in meter perception.

    PubMed

    Kalender, Beste; Trehub, Sandra E; Schellenberg, E Glenn

    2013-03-01

    We examined the influence of incidental exposure to varied metrical patterns from different musical cultures on the perception of complex metrical structures from an unfamiliar musical culture. Adults who were familiar with Western music only (i.e., simple meters) and those who also had limited familiarity with non-Western music were tested on their perception of metrical organization in unfamiliar (Turkish) music with simple and complex meters. Adults who were familiar with Western music detected meter-violating changes in Turkish music with simple meter but not in Turkish music with complex meter. Adults with some exposure to non-Western music that was unmetered or metrically complex detected meter-violating changes in Turkish music with both simple and complex meters, but they performed better on patterns with a simple meter. The implication is that familiarity with varied metrical structures, including those with a non-isochronous tactus, enhances sensitivity to the metrical organization of unfamiliar music. PMID:22367155

  13. Electrostatic ion (hydrogen) cyclotron and ion acoustic wave instabilities in regions of upward field-aligned current and upward ion beams

    NASA Astrophysics Data System (ADS)

    Bergmann, R.

    1984-02-01

    An investigation is made into the stability of electrostatic hydrogen ion cyclotron and ion acoustic waves in a model plasma where an ion beam, population 2, and oppositely directed drifting electrons pass through a stationary ion background, population 1. The excited wave properties are then compared with the characteristics of the unstable modes observed on the S3-3 satellite. Three temperature regimes are studied: (1) Te greater than Ti2 much greater than Ti1, (2) Ti2 greater than Te not less than Ti1, and (3) Te approximately equal to Ti1 greater than Ti2. It is found that the ion beam acts as a free energy source only in regime 1. This regime is also highly unstable to the electrons as a free energy source. Unstable modes in regimes 2 and 3 seem to best satisfy the electrostatic hydrogen cyclotron wave (EHC) properties at 1 earth radius. For these cases the electrons are the free energy source, the beam supplies damping.

  14. Imaging marine geophysical environments with vector acoustics.

    PubMed

    Lindwall, Dennis

    2006-09-01

    Using vector acoustic sensors for marine geoacoustic surveys instead of the usual scalar hydrophones enables one to acquire three-dimensional (3D) survey data with instrumentation and logistics similar to current 2D surveys. Vector acoustic sensors measure the sound wave direction directly without the cumbersome arrays that hydrophones require. This concept was tested by a scaled experiment in an acoustic water tank that had a well-controlled environment with a few targets. Using vector acoustic data from a single line of sources, the three-dimensional tank environment was imaged by directly locating the source and all reflectors. PMID:17004497

  15. Simulating Reflex Induced Changes in the Acoustic Impedance of the Ear.

    ERIC Educational Resources Information Center

    Sirlin, Mindy W.; Levitt, Harry

    1991-01-01

    A simple procedure for measuring changes in the acoustic impedance of the ear is described. The technique has several applications, including simulation using a standard coupler of changes in real ear impedance produced by the acoustic reflex, and calibration of response time of an otoadmittance meter. (Author/DB)

  16. PRESCILA: a new, lightweight neutron rem meter.

    PubMed

    Olsher, Richard H; Seagraves, David T; Eisele, Shawna L; Bjork, Christopher W; Martinez, William A; Romero, Leonard L; Mallett, Michael W; Duran, Michael A; Hurlbut, Charles R

    2004-06-01

    Conventional neutron rem meters currently in use are based on 1960's technology that relies on a large neutron moderator assembly surrounding a thermal detector to achieve a rem-like response function over a limited energy range. Such rem meters present an ergonomic challenge, being heavy and bulky, and have caused injuries during radiation protection surveys. Another defect of traditional rem meters is a poor high-energy response above 10 MeV, which makes them unsuitable for applications at high-energy accelerator facilities. Proton Recoil Scintillator-Los Alamos (PRESCILA) was developed as a low-weight (2 kg) alternative capable of extended energy response, high sensitivity, and moderate gamma rejection. An array of ZnS(Ag) based scintillators is located inside and around a Lucite light guide, which couples the scintillation light to a sideview bialkali photomultiplier tube. The use of both fast and thermal scintillators allows the energy response function to be optimized for a wide range of operational spectra. The light guide and the borated polyethylene frame provide moderation for the thermal scintillator element. The scintillators represent greatly improved versions of the Hornyak and Stedman designs from the 1950's, and were developed in collaboration with Eljen Technology. The inherent pulse height advantage of proton recoils over electron tracks in the phosphor grains eliminates the need for pulse shape discrimination and makes it possible to use the PRESCILA probe with standard pulse height discrimination provided by off-the-shelf health physics counters. PRESCILA prototype probes have been extensively tested at both Los Alamos and the German Bureau of Standards, Physikalisch-Technische Bundesanstalt. Test results are presented for energy response, directional dependence, linearity, sensitivity, and gamma rejection. Initial field tests have been conducted at Los Alamos and these results are also given. It is concluded that PRESCILA offers a viable

  17. 10 CFR 451.7 - Metering requirements.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 3 2011-01-01 2011-01-01 false Metering requirements. 451.7 Section 451.7 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION RENEWABLE ENERGY PRODUCTION INCENTIVES § 451.7 Metering requirements... renewable energy facility must be measured by a standard metering device that— (a) Meets generally...

  18. 10 CFR 451.7 - Metering requirements.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 3 2013-01-01 2013-01-01 false Metering requirements. 451.7 Section 451.7 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION RENEWABLE ENERGY PRODUCTION INCENTIVES § 451.7 Metering requirements... renewable energy facility must be measured by a standard metering device that— (a) Meets generally...

  19. 10 CFR 451.7 - Metering requirements.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 3 2014-01-01 2014-01-01 false Metering requirements. 451.7 Section 451.7 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION RENEWABLE ENERGY PRODUCTION INCENTIVES § 451.7 Metering requirements... renewable energy facility must be measured by a standard metering device that— (a) Meets generally...

  20. 10 CFR 451.7 - Metering requirements.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 3 2012-01-01 2012-01-01 false Metering requirements. 451.7 Section 451.7 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION RENEWABLE ENERGY PRODUCTION INCENTIVES § 451.7 Metering requirements... renewable energy facility must be measured by a standard metering device that— (a) Meets generally...

  1. 10 CFR 451.7 - Metering requirements.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 3 2010-01-01 2010-01-01 false Metering requirements. 451.7 Section 451.7 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION RENEWABLE ENERGY PRODUCTION INCENTIVES § 451.7 Metering requirements... renewable energy facility must be measured by a standard metering device that— (a) Meets generally...

  2. Embedded solution for a microwave moisture meter

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this paper, the conversion of a PC or laptop-controlled microwave moisture meter to a stand-alone meter hosting its own embedded system is discussed. The moisture meter is based on the free-space transmission measurement technique and uses low-intensity microwaves to measure the attenuation and p...

  3. 78 FR 20628 - Wireless Metering Challenge

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-05

    ... of Energy Efficiency and Renewable Energy Wireless Metering Challenge AGENCY: Office of Energy... (EERE) requests comments on the draft version of the Wireless Power Meter Challenge Specification. This... development of new technologies in the wireless electric metering space. DATES: Comments on the Wireless...

  4. Ultrasonic velocity meter used in stream gaging

    USGS Publications Warehouse

    Fayard, L.D.

    1991-01-01

    Many streams and canals in Florida are affected by tides or control structures and experience very low flow velocities at times. For example, the St. Johns River in northeastern Florida is affected by tides for about 140 miles upstream from its mouth and many canals in the Miami area of southeastern Florida are controlled by manmade structures and other elements that cause a variable backwater effect and very low flow velocities. For these conditions, it becomes necessary to obtain a continuous index of mean velocity as well as stage in order to compute discharge. Point-velocity sensing systems have been used to relate point velocity to mean velocity but their usefulness commonly is limited because of the lack of an exact relation. The ultrasonic velocity meter (UVM) provides an alternative approach to measuring a velocity index that can be related to mean velocity; one that provides an integrated velocity at a prescribed elevation across a stream. Six stations in the tidal-affected lower St. Johns River basin are presently equipped with UVM's. Measuring sections are as narrow as 100 feet and as wide as 900 feet. Multiple acoustic paths are used to measure wide sections in a straight reach of river; crossing paths are used to measure sections in a bend of the river. Because of low velocity and variable backwater conditions, flow also is measured with UVM's in 11 canals in the Miami area that drain into The Everglades. At some of the canal sites transducers have been permanently mounted and a 'portable' UVM module is used to obtain instantaneous velocity readings.

  5. Acoustic transducer

    DOEpatents

    Drumheller, D.S.

    1997-12-30

    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.

  6. Acoustic transducer

    DOEpatents

    Drumheller, Douglas S.

    1997-01-01

    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.

  7. Acoustic systems for the measurement of streamflow

    USGS Publications Warehouse

    Laenen, Antonius; Smith, Winchell

    1982-01-01

    Very little information is available concerning acoustic velocity meter (AVM) operation, performance, and limitations. This report provides a better understanding about the application of AVM instrumentation to streamflow measurment. Operational U.S. Geological Survey systems have proven that AVM equipment is accurate and dependable. AVM equipment has no practical upper limit of measureable velocity if sonic transducers are securely placed and adequately protected, and will measure velocitites as low as 0.1 meter per second which is normally less than the threshold level for mechanical or head-loss meters. In some situations the performance of AVM equipment may be degraded by multipath interference, signal bending, signal attenuation, and variable streamline orientation. Smaller, less-expensive, more conveniently operable microprocessor equipment is now available which should increase use of AVM systems in streamflow applications. (USGS)

  8. Electromagnetic acoustic transducer

    DOEpatents

    Alers, George A.; Burns, Jr., Leigh R.; MacLauchlan, Daniel T.

    1988-01-01

    A noncontact ultrasonic transducer for studying the acoustic properties of a metal workpiece includes a generally planar magnetizing coil positioned above the surface of the workpiece, and a generally planar eddy current coil between the magnetizing coil and the workpiece. When a large current is passed through the magnetizing coil, a large magnetic field is applied to the near-surface regions of the workpiece. The eddy current coil can then be operated as a transmitter by passing an alternating current therethrough to excite ultrasonic waves in the surface of the workpiece, or operated as a passive receiver to sense ultrasonic waves in the surface by measuring the output signal. The geometries of the two coils can be varied widely to be effective for different types of ultrasonic waves. The coils are preferably packaged in a housing which does not interfere with their operation, but protects them from a variety of adverse environmental conditions.

  9. Profile measurements and data from the 2011 Optics, Acoustics, and Stress In Situ (OASIS) project at the Martha's Vineyard Coastal Observatory

    USGS Publications Warehouse

    Sherwood, Christopher R.; Dickhudt, Patrick J.; Martini, Marinna A.; Montgomery, Ellyn T.; Boss, Emmanuel S.

    2012-01-01

    This report documents data collected by the U.S. Geological Survey (USGS) for the Coastal Model Applications and Field Measurements project under the auspices of the U.S. Navy Office of Naval Research Optics, Acoustics, and Stress In Situ (OASIS) Project. The objective of the measurements was to relate optical and acoustic properties of suspended particles to changes in particle size, concentration, and vertical distribution in the bottom boundary layer near the seafloor caused by wave- and current-induced stresses. This information on the physics of particle resuspension and aggregation and light penetration and water clarity will help improve models of sediment transport, benthic primary productivity, and underwater visibility. There is well-established technology for acoustic profiling, but optical profiles are more difficult to obtain because of the rapid attenuation of light in water. A specially modified tripod with a moving arm was designed to solve this problem by moving instruments vertically in the bottom boundary layer, between the bottom and about 2 meters above the seafloor. The profiling arm was designed, built, and tested during spring and summer 2011 by a team of USGS scientists, engineers, and technicians. To accommodate power requirements and the large data files recorded by some of the optical instruments, the tripod was connected via underwater cable to the Martha's Vineyard Coastal Observatory, operated by the Woods Hole Oceanographic Institution (WHOI). This afforded real-time Internet communication with the embedded computers aboard the tripod. Instruments were mounted on the profiling arm, and additional instruments were mounted elsewhere on the tripod and nearby on the seafloor. The tripod and a small mooring for a profiling current meter were deployed on September 17, 2011, at the Martha's Vineyard Coastal Observatory 12-meter-deep underwater node about 2 kilometers south of Martha's Vineyard, Massachusetts. Divers assisted in the

  10. How Coriolis meter design affects field performance

    SciTech Connect

    Levien, A.; Dudiak, A.

    1995-12-31

    Although many possibilities exist for the design of Coriolis flowmeters, a common set of fundamental physical principles affect practical meter design. Design criteria such as tube geometry, alloy section, operating frequencies, stress levels, and tubing wall thickness have varying impacts on meter performance. Additionally, field conditions such as changing temperature, pressure, pipeline stress and vibration affect measurement performance. The challenge created in Coriolis flow meter design is to maximize the sensitivity of the meter Coriolis forces, while minimizing the impact of outside environmental influences. Data are presented on the physical principles that affect Coriolis flowmeters, and how the various aspects of meter design influence field performance.

  11. Five meter diameter conical furlable antenna

    NASA Technical Reports Server (NTRS)

    Fortenberry, J. W.; Freeland, R. E.; Moore, D. M.

    1976-01-01

    An investigation was made to demonstrate that a 5-meter-diameter, furlable, conical reflector antenna utilizing a line source feed can be fabricated utilizing composite materials and to prove that the antenna can function mechanically and electrically as prototype flight hardware. The design, analysis, and testing of the antenna are described. An RF efficiency of 55% at 8.5 GHz and a surface error of 0.64 mm rms were chosen as basic design requirements. Actual test measurements yielded an efficiency of 53% (49.77 dB gain) and a surface error of 0.61 mm rms. Atmospherically induced corrosion of the reflector mesh resulted in the RF performance degradation. An assessment of the antenna as compared to the current state of the art technology was made. This assessment included cost, surface accuracy and RF performance, structural and mechanical characteristics, and possible applications.

  12. Acoustic cryocooler

    DOEpatents

    Swift, Gregory W.; Martin, Richard A.; Radenbaugh, Ray

    1990-01-01

    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.

  13. Acoustic transducer

    DOEpatents

    Drumheller, Douglas S.

    2000-01-01

    An active acoustic transducer tool for use down-hole applications. The tool includes a single cylindrical mandrel including a shoulder defining the boundary of a narrowed portion over which is placed a sandwich-style piezoelectric tranducer assembly. The piezoelectric transducer assembly is prestressed by being placed in a thermal interference fit between the shoulder of the mandrel and the base of an anvil which is likewise positioned over the narrower portion of the mandrel. In the preferred embodiment, assembly of the tool is accomplished using a hydraulic jack to stretch the mandrel prior to emplacement of the cylindrical sandwich-style piezoelectric transducer assembly and anvil. After those elements are positioned and secured, the stretched mandrel is allowed to return substantially to its original (pre-stretch) dimensions with the result that the piezoelectric transducer elements are compressed between the anvil and the shoulder of the mandrel.

  14. Acoustic hemostasis

    NASA Astrophysics Data System (ADS)

    Crum, L.; Andrew, M.; Bailey, M.; Beach, K.; Brayman, A.; Curra, F.; Kaczkowski, P.; Kargl, S.; Martin, R.; Vaezy, S.

    2003-04-01

    Over the past several years, the Center for Industrial and Medical Ultrasound (CIMU) at the Applied Physics Laboratory in the University of Washington has undertaken a broad research program in the general area of High Intensity Focused Ultrasound (HIFU). Our principal emphasis has been on the use of HIFU to induce hemostasis; in particular, CIMU has sought to develop a small, lightweight, portable device that would use ultrasound for both imaging and therapy. Such a technology is needed because nearly 50% of combat casualty mortality results from exsanguinations, or uncontrolled bleeding. A similar percentage occurs for civilian death due to trauma. In this general review, a presentation of the general problem will be given, as well as our recent approaches to the development of an image-guided, transcutaneous, acoustic hemostasis device. [Work supported in part by the USAMRMC, ONR and the NIH.

  15. Discussion series on PURPA related topics: metering

    SciTech Connect

    Sturgeon, J I

    1980-08-01

    Time-differentiated metering of electricity consumption and demand is required in both rate-structure experimentation and the implementation of most time-of-use rate designs. Time-differentiated metering takes three major forms: multi-register watthour meters, magnetic-tape recording meters, and remote automatic meter-reading systems. The majority of projects selected magnetic-tape meters for their flexibility with respect to rate structure, load-survey capabilities, and ready availability. The small-scale, experimental nature of the projects reduced the significance of the large difference in per-unit cost and operational/maintenance complexity between this form of metering and the multi-register form. Magnetic-tape meters are not likely candidates for system-wide implementation of time-differentiated metering. Automatic remote-meter-reading systems were not adequately available during the project years; those projects attempting to use these were unable to bring them to full operational status before project termination, due to the many problems of design, quality control, and equipment acquisition encountered. Delays in acquisition and problems of quality control also followed the selection of magnetic-tape meters and multi-register meters by a number of the projects. Though less complex than automatic remote-reading systems, these technologies are still new and more complex than standard watthour metering. Thus, both equipment vendors and utilities encountered numerous problems in getting properly functioning meters to the service entrances on time. A variety of factors contributed to installation delays, including unforeseen space limitations, incompatible wiring, problems of task organization, and customer reluctance.

  16. Inlet total pressure loss due to acoustic wall treatment

    NASA Technical Reports Server (NTRS)

    Miller, B. A.

    1977-01-01

    The effect of diffuser wall acoustic treatment on inlet total pressure loss was experimentally determined. Data were obtained by testing an inlet model with 10 different acoustically treated diffusers differing only in the design of the Helmholtz resonator acoustic treatment. Tests were conducted in a wind tunnel at forward velocities to 41 meters per second for inlet throat Mach numbers of .5 to .8 and angles of attack as high as 50 degrees. Results indicate a pressure loss penalty due to acoustic treatment that increases linearly with the porosity of the acoustic facing sheet. For a surface porosity of 14 percent the total pressure loss was 21 percent greater than that for an untreated inlet.

  17. Net Metering and Interconnection Procedures-- Incorporating Best Practices

    SciTech Connect

    Jason Keyes, Kevin Fox, Joseph Wiedman, Staff at North Carolina Solar Center

    2009-04-01

    State utility commissions and utilities themselves are actively developing and revising their procedures for the interconnection and net metering of distributed generation. However, the procedures most often used by regulators and utilities as models have not been updated in the past three years, in which time most of the distributed solar facilities in the United States have been installed. In that period, the Interstate Renewable Energy Council (IREC) has been a participant in more than thirty state utility commission rulemakings regarding interconnection and net metering of distributed generation. With the knowledge gained from this experience, IREC has updated its model procedures to incorporate current best practices. This paper presents the most significant changes made to IREC’s model interconnection and net metering procedures.

  18. Discuss the testing problems of ultraviolet irradiance meters

    NASA Astrophysics Data System (ADS)

    Ye, Jun'an; Lin, Fangsheng

    2014-09-01

    Ultraviolet irradiance meters are widely used in many areas such as medical treatment, epidemic prevention, energy conservation and environment protection, computers, manufacture, electronics, ageing of material and photo-electric effect, for testing ultraviolet irradiance intensity. So the accuracy of value directly affects the sterile control in hospital, treatment, the prevention level of CDC and the control accuracy of curing and aging in manufacturing industry etc. Because the display of ultraviolet irradiance meters is easy to change, in order to ensure the accuracy, it needs to be recalibrated after being used period of time. By the comparison with the standard ultraviolet irradiance meters, which are traceable to national benchmarks, we can acquire the correction factor to ensure that the instruments working under accurate status and giving the accurate measured data. This leads to an important question: what kind of testing device is more accurate and reliable? This article introduces the testing method and problems of the current testing device for ultraviolet irradiance meters. In order to solve these problems, we have developed a new three-dimensional automatic testing device. We introduce structure and working principle of this system and compare the advantages and disadvantages of two devices. In addition, we analyses the errors in the testing of ultraviolet irradiance meters.

  19. Remote semi-continuous flow rate logging seepage meter

    NASA Technical Reports Server (NTRS)

    Reay, William G.; Walthall, Harry G.

    1991-01-01

    The movement of groundwater and its associated solutes from upland regions was implicated in the degradation of receiving surface water bodies. Current efforts to directly measure this influx of water incorporate manually operated seepage meters which are hindered by severe limitations. A prototype seepage meter was developed by NASA Langley Research Center and Virginia Polytechnic Institute and State University that will allow for the semi-continuous collection and data logging of seepage flux across the sediment water interface. The meter is designed to operate at depths to 40 meters, and alleviate or minimize all disadvantages associated with traditional methods while remaining cost effective. The unit was designed to operate independently for time periods on the order of weeks with adjustable sample sequences depending upon hydrologic conditions. When used in conjunction with commercially available pressure transducers, this seepage meter allows for correlations to be made between groundwater discharge and tidal/sea state conditions in coastal areas. Field data from the Chesapeake Bay and Florida Bay systems are presented.

  20. Distributed Brillouin sensing with sub-meter spatial resolution: modeling and processing.

    PubMed

    Beugnot, Jean-Charles; Tur, Moshe; Mafang, Stella Foaleng; Thévenaz, Luc

    2011-04-11

    A general analytic solution for Brillouin distributed sensing in optical fibers with sub-meter spatial resolution is obtained by solving the acoustical-optical coupled wave equations by a perturbation method. The Brillouin interaction of a triad of square pump pulses with a continuous signal is described, covering a wide range of pumping schemes. The model predicts how the acoustic wave, the signal amplitude and the optical gain spectral profile depend upon the pumping scheme. Sub-meter spatial resolution is demonstrated for bright-, dark- and π-shifted interrogating pump pulses, together with disturbing echo effects, and the results compare favorably with experimental data. This analytic solution is an excellent tool not only for optimizing the pumping scheme but also for post-processing the measured data to remove resolution degrading features. PMID:21503049

  1. Development and evaluation of a meter for measuring return line fluid flow rates during drilling

    SciTech Connect

    Loeppke, G.E.; Schafer, D.M.; Glowka, D.A.; Scott, D.D.; Wernig, M.D. ); Wright, E.K. )

    1992-06-01

    The most costly problem routinely encountered in geothermal drilling is lost circulation, which occurs when drilling fluid is lost to the formation rather than circulating back to the surface. The successful and economical treatment of lost circulation requires the accurate measurement of drilling fluid flow rate both into and out of the well. This report documents the development of a meter for measuring drilling fluid outflow rates in the return line of a drilling rig. The meter employs a rolling counterbalanced float that rides on the surface of the fluid in the return line. The angle of the float pivot arm is sensed with a pendulum potentiometer, and the height of the float is calculated from this measurement. The float height is closely related to the fluid height and, therefore, the flow rate in the line. The prototype rolling float meter was extensively tested under laboratory conditions in the Wellbore Hydraulics Flow Facility; results from these tests were used in the design of the field prototype rolling float meter. The field prototype meter was tested under actual drilling conditions in August and September 1991 at the Long Valley Exploratory Well near Mammoth Lakes, Ca. In addition, the performance of several other commercially available inflow and outflow meters was evaluated in the field. The tested inflow meters included conventional pump stroke counters, rotary pump speed counters, magnetic flowmeters, and an ultrasonic Doppler flowmeter. On the return flow line, a standard paddlemeter, an acoustic level meter, and the prototype rolling float meter were evaluated for measuring drilling fluid outflow rates.

  2. Inherent limitations of nondestructive chlorophyll meters: a comparison of two types of meters

    NASA Technical Reports Server (NTRS)

    Monje, O. A.; Bugbee, B.

    1992-01-01

    Two types of nondestructive chlorophyll meters were compared with a standard, destructive chlorophyll measurement technique. The nondestructive chlorophyll meters were 1) a custom built, single-wavelength meter, and 2) the recently introduced, dual-wavelengh, chlorophyll meter from Minolta (model SPAD-502). Data from both meters were closely correlated with destructive measurements of chlorophyll (r2 = 0.90 and 0.93; respectively) for leaves with chlorophyll concentrations ranging from 100 to 600 mg m-2, but both meters consistently overestimated chlorophyll outside this range. Although the dual-wavelength meter was slightly more accurate than the single-wavelength meter (higher r2), the light-scattering properties of leaf cells and the nonhomogeneous distribution of chlorophyll in leaves appear to limit the ability of all meters to estimate in vivo chlorophyll concentration.

  3. Inherent limitations of nondestructive chlorophyll meters: a comparison of two types of meters.

    PubMed

    Monje, O A; Bugbee, B

    1992-01-01

    Two types of nondestructive chlorophyll meters were compared with a standard, destructive chlorophyll measurement technique. The nondestructive chlorophyll meters were 1) a custom built, single-wavelength meter, and 2) the recently introduced, dual-wavelengh, chlorophyll meter from Minolta (model SPAD-502). Data from both meters were closely correlated with destructive measurements of chlorophyll (r2 = 0.90 and 0.93; respectively) for leaves with chlorophyll concentrations ranging from 100 to 600 mg m-2, but both meters consistently overestimated chlorophyll outside this range. Although the dual-wavelength meter was slightly more accurate than the single-wavelength meter (higher r2), the light-scattering properties of leaf cells and the nonhomogeneous distribution of chlorophyll in leaves appear to limit the ability of all meters to estimate in vivo chlorophyll concentration. PMID:11537728

  4. A Mobile-Phone-Based Breath Carbon Monoxide Meter to Detect Cigarette Smoking

    PubMed Central

    2014-01-01

    Introduction: Mobile phones hold considerable promise for delivering evidence-based smoking cessation interventions that require frequent and objective assessment of smoking status via breath carbon monoxide (Breath CO) measurement. However, there are currently no commercially available mobile-phone-based Breath CO meters. We developed a mobile-phone-based Breath CO meter prototype that attaches to and communicates with a smartphone through an audio port. We then evaluated the reliability and the validity of Breath CO measures collected with the mobile meter prototype and assessed the usability and acceptability of the meter. Methods: Participants included 20 regular smokers (≥10 cigarettes/day), 20 light smokers (<10 cigarettes/day), and 20 nonsmokers. Expired air samples were collected 4 times from each participant: twice with the mobile meter and twice with a commercially available Breath CO meter. Results: Measures calculated by the mobile meter correlated strongly with measures calculated by the commercial meter (r = .96, p < .001). Additionally, the mobile meter accurately distinguished between smokers and nonsmokers. The area under the receiver-operating characteristic curve for the mobile meter was 94.7%, and the meter had a combined sensitivity and specificity of 1.86 at an abstinence threshold of ≤6 ppm. Responses on an acceptability survey indicated that smokers liked the meter and would be interested in using it during a quit attempt. Conclusions: The results of our study suggest that a mobile-phone-based Breath CO meter is a reliable, valid, and acceptable device for distinguishing between smokers and nonsmokers. PMID:24470633

  5. Acoustic hemostasis

    NASA Astrophysics Data System (ADS)

    Crum, Lawrence; Beach, Kirk; Carter, Stephen; Chandler, Wayne; Curra, Francesco; Kaczkowski, Peter; Keilman, George; Khokhlova, Vera; Martin, Roy; Mourad, Pierre; Vaezy, Shahram

    2000-07-01

    In cases of severe injury, physicians speak of a "golden hour"—a brief grace period in which quickly applied, proper therapy can save the life of the patient. Much of this mortality results from exsanguination, i.e., bleeding to death—often from internal hemorrhage. The inability of a paramedic to treat breaches in the vascular system deep within the body or to stem the loss of blood from internal organs is a major reason for the high level of mortality associated with blunt trauma. We have undertaken an extensive research program to treat the problem of internal bleeding. Our approach is as follows: (a) We use scanning ultrasound to identify internal bleeding and hemorrhage, (b) we use ultrasound imaging to locate specific breaches in the vascular system, both from damaged vessels and gross damage to the capillary bed, and (c) we use High Intensity Focused Ultrasound (HIFU) to treat the damaged region and to induce hemostasis. We present a general review of this research with some emphasis on the role of nonlinear acoustics.

  6. Acoustic Localization with Infrasonic Signals

    NASA Astrophysics Data System (ADS)

    Threatt, Arnesha; Elbing, Brian

    2015-11-01

    Numerous geophysical and anthropogenic events emit infrasonic frequencies (<20 Hz), including volcanoes, hurricanes, wind turbines and tornadoes. These sounds, which cannot be heard by the human ear, can be detected from large distances (in excess of 100 miles) due to low frequency acoustic signals having a very low decay rate in the atmosphere. Thus infrasound could be used for long-range, passive monitoring and detection of these events. An array of microphones separated by known distances can be used to locate a given source, which is known as acoustic localization. However, acoustic localization with infrasound is particularly challenging due to contamination from other signals, sensitivity to wind noise and producing a trusted source for system development. The objective of the current work is to create an infrasonic source using a propane torch wand or a subwoofer and locate the source using multiple infrasonic microphones. This presentation will present preliminary results from various microphone configurations used to locate the source.

  7. Acoustic metasurface with hybrid resonances.

    PubMed

    Ma, Guancong; Yang, Min; Xiao, Songwen; Yang, Zhiyu; Sheng, Ping

    2014-09-01

    An impedance-matched surface has the property that an incident wave generates no reflection. Here we demonstrate that by using a simple construction, an acoustically reflecting surface can acquire hybrid resonances and becomes impedance-matched to airborne sound at tunable frequencies, such that no reflection is generated. Each resonant cell of the metasurface is deep-subwavelength in all its spatial dimensions, with its thickness less than the peak absorption wavelength by two orders of magnitude. As there can be no transmission, the impedance-matched acoustic wave is hence either completely absorbed at one or multiple frequencies, or converted into other form(s) of energy, such as an electrical current. A high acoustic-electrical energy conversion efficiency of 23% is achieved. PMID:24880731

  8. Off-level corrections for gravity meters

    NASA Astrophysics Data System (ADS)

    Niebauer, T. M.; Blitz, Thomas; Constantino, Andy

    2016-04-01

    Gravity meters must be aligned with the local gravity at any location on the surface of the earth in order to measure the full amplitude of the gravity vector. The gravitational force on the sensitive component of the gravity meter decreases by the cosine of the angle between the measurement axis and the local gravity vector. Most gravity meters incorporate two horizontal orthogonal levels to orient the gravity meter for a maximum gravity reading. In order to calculate a gravity correction it is often necessary to estimate the overall angular deviation between the gravity meter and the local gravity vector using two measured horizontal tilt meters. Typically this is done assuming that the two horizontal angles are independent and that the product of the cosines of the horizontal tilts is equivalent to the cosine of the overall deviation. These approximations, however, break down at large angles. This paper derives analytic formulae to transform angles measured by two orthogonal tilt meters into the vertical deviation of the third orthogonal axis. The equations can be used to calibrate the tilt sensors attached to the gravity meter or provide a correction for a gravity meter used in an off-of-level condition.

  9. Eddy-Current Meter Would Check Weld Wire Online

    NASA Technical Reports Server (NTRS)

    Bailey, G. R.

    1982-01-01

    Simple Technique samples an entire spool of welding wire to test for contamination or unauthorized filler wire. Since unit monitors entire length of wire used in welding, completed welds need not be inspected individually. Technique would save time, avoiding human interface and production delays.

  10. A seepage meter designed for use in flowing water

    USGS Publications Warehouse

    Rosenberry, D.O.

    2008-01-01

    Seepage meters provide one of the most direct means to measure exchange of water across the sediment-water interface, but they generally have been unsuitable for use in fluvial settings. Although the seepage bag can be placed inside a rigid container to minimize velocity head concerns, the seepage cylinder installed in the sediment bed projects into and disrupts the flow field, altering both the local-scale fluid exchange as well as measurement of that exchange. A low-profile seepage meter designed for use in moving water was tested in a seepage meter flux tank where both current velocity and seepage velocity could be controlled. The conical seepage cylinder protrudes only slightly above the sediment bed and is connected via tubing to a seepage bag or flowmeter positioned inside a rigid shelter that is located nearby where current velocity is much slower. Laboratory and field tests indicate that the net effect of the small protrusion of the seepage cylinder into the surface water flow field is inconsequentially small for surface water currents up to 65 cm s-1. Current velocity affects the variability of seepage measurements; seepage standard deviation increased from ???2 to ???6 cm d-1 as current velocity increased from 9 to 65 cm s-1. Substantial bias can result if the shelter is not placed to minimize hydraulic gradient between the bag and the seepage cylinder.

  11. Ion temperature anisotropy effects on the dispersion relation and threshold conditions of a sheared current-driven electrostatic ion-acoustic instability with applications to the collisional high-latitude F-region

    NASA Astrophysics Data System (ADS)

    Perron, Patrick J. G.; Noël, J.-M.; St-Maurice, J.-P.; Kabin, K.

    2015-01-01

    Plasma instabilities play a important role in producing small-scale irregularities in the ionosphere. In particular, current-driven electrostatic ion-acoustic (CDEIA) instabilities contribute to high-latitude F-region electrodynamics. Ion temperature anisotropies with enhanced perpendicular temperature often exist in the high-latitude F-region. In addition to temperature anisotropies, ion velocity shears are observed near auroral arc edges, sometimes coexisting with thermal ion upflow processes and field-aligned currents (FAC). We investigated whether ion temperature anisotropy lowers the threshold conditions required for the onset of sheared CDEIA instabilities. We generalised a dispersion relation to include ion thermal anisotropy, finite Larmor radius corrections and collisions. We derived new fluid-like analytical expressions for the threshold conditions required for instability that depend explicitly on ion temperature anisotropy. We studied how the instability threshold conditions vary as a function of the wave vector direction in both fluid and kinetic regimes. We found that, despite the dampening effect of collisions on ion-acoustic waves, ion temperature anisotropy lowers in some cases the threshold drift requirements for a large range of oblique wave vector angles. More importantly, realistic ion temperature anisotropies contribute to reducing the instability threshold velocity shears that are associated with small drift thresholds, for modes propagating almost perpendicularly to the geomagnetic field. Small shear thresholds that seem to be sustainable in the ionospheric F-region are obtained for low-frequency waves. Such instabilities could play a role in the direct generation of field-aligned irregularities in the collisional F-region that could be observed with the Super Dual Auroral Radar Network (SuperDARN) array of high-frequency radars. These modes would be very sensitive to the radar probing direction since they are restricted to very narrow

  12. Acoustic source for generating an acoustic beam

    DOEpatents

    Vu, Cung Khac; Sinha, Dipen N.; Pantea, Cristian

    2016-05-31

    An acoustic source for generating an acoustic beam includes a housing; a plurality of spaced apart piezo-electric layers disposed within the housing; and a non-linear medium filling between the plurality of layers. Each of the plurality of piezoelectric layers is configured to generate an acoustic wave. The non-linear medium and the plurality of piezo-electric material layers have a matching impedance so as to enhance a transmission of the acoustic wave generated by each of plurality of layers through the remaining plurality of layers.

  13. Progress in acoustic holography

    NASA Astrophysics Data System (ADS)

    Hildebrand, B. P.

    1985-01-01

    The theory underlying the methods used in acoustic holography (the real-time liquid surface levitation and the scanning holography methods) and in electromagnetic holography, which uses electromagnetic impulses (radar) or electromagnetic waves (eddy current) is developed. These holographic techniques are illustrated with experimental results, including the use of the liquid surface levitation method for inspecting fiberglass laminate tubes, and examples of the time-of-flight holographic images, the coherent ultrasonic images, multifrequency ultrasonic images, and the synthetic aperture holography images obtained by the use of the scanning holography methodology. Other examples illustrate applications of radar holography and eddy current holography. These examples are used to refute some traditional negative comments on nonoptical holography.

  14. ELECTROMAGNETISM, OPTICS, ACOUSTICS, HEAT TRANSFER, CLASSICAL MECHANICS, AND FLUID DYNAMICS: Analytical Solutions of Electromagnetic Fields from Current Dipole Moment on Spherical Conductor in a Low-Frequency Approximation

    NASA Astrophysics Data System (ADS)

    Okita, Taishi; Takagi, Toshiyuki

    2010-01-01

    We analytically derive the solutions for electromagnetic fields of electric current dipole moment, which is placed in the exterior of the spherical homogeneous conductor, and is pointed along the radial direction. The dipole moment is driven in the low frequency f = 1 kHz and high frequency f = 1 GHz regimes. The electrical properties of the conductor are appropriately chosen in each frequency. Electromagnetic fields are rigorously formulated at an arbitrary point in a spherical geometry, in which the magnetic vector potential is straightforwardly given by the Biot-Savart formula, and the scalar potential is expanded with the Legendre polynomials, taking into account the appropriate boundary conditions at the spherical surface of the conductor. The induced electric fields are numerically calculated along the several paths in the low and high frequeny excitation. The self-consistent solutions obtained in this work will be of much importance in a wide region of electromagnetic induction problems.

  15. Acoustic Holography

    NASA Astrophysics Data System (ADS)

    Kim, Yang-Hann

    One of the subtle problems that make noise control difficult for engineers is the invisibility of noise or sound. A visual image of noise often helps to determine an appropriate means for noise control. There have been many attempts to fulfill this rather challenging objective. Theoretical (or numerical) means for visualizing the sound field have been attempted, and as a result, a great deal of progress has been made. However, most of these numerical methods are not quite ready for practical applications to noise control problems. In the meantime, rapid progress with instrumentation has made it possible to use multiple microphones and fast signal-processing systems. Although these systems are not perfect, they are useful. A state-of-the-art system has recently become available, but it still has many problematic issues; for example, how can one implement the visualized noise field. The constructed noise or sound picture always consists of bias and random errors, and consequently, it is often difficult to determine the origin of the noise and the spatial distribution of the noise field. Section 26.2 of this chapter introduces a brief history, which is associated with sound visualization, acoustic source identification methods and what has been accomplished with a line or surface array. Section 26.2.3 introduces difficulties and recent studies, including de-Dopplerization and de-re verberation methods, both essential for visualizing a moving noise source, such as occurs for cars or trains. This section also addresses what produces ambiguity in realizing real sound sources in a room or closed space. Another major issue associated with sound/noise visualization is whether or not we can distinguish between mutual dependencies of noise in space (Sect. 26.2.4); for example, we are asked to answer the question, Can we see two birds singing or one bird with two beaks?

  16. Acoustic Holography

    NASA Astrophysics Data System (ADS)

    Kim, Yang-Hann

    One of the subtle problems that make noise control difficult for engineers is the invisibility of noise or sound. A visual image of noise often helps to determine an appropriate means for noise control. There have been many attempts to fulfill this rather challenging objective. Theoretical (or numerical) means for visualizing the sound field have been attempted, and as a result, a great deal of progress has been made. However, most of these numerical methods are not quite ready for practical applications to noise control problems. In the meantime, rapid progress with instrumentation has made it possible to use multiple microphones and fast signal-processing systems. Although these systems are not perfect, they are useful. A state-of-the-art system has recently become available, but it still has many problematic issues; for example, how can one implement the visualized noise field. The constructed noise or sound picture always consists of bias and random errors, and consequently, it is often difficult to determine the origin of the noise and the spatial distribution of the noise field. Section 26.2 of this chapter introduces a brief history, which is associated with "sound visualization," acoustic source identification methods and what has been accomplished with a line or surface array. Section 26.2.3 introduces difficulties and recent studies, including de-Dopplerization and de-reverberation methods, both essentialfor visualizing a moving noise source, such as occurs for cars or trains. This section also addresses what produces ambiguity in realizing real sound sources in a room or closed space. Another major issue associated with sound/noise visualization is whether or not we can distinguish between mutual dependencies of noise in space (Sect. 26.2.4); for example, we are asked to answer the question, "Can we see two birds singing or one bird with two beaks?"

  17. First images of thunder: Acoustic imaging of triggered lightning

    NASA Astrophysics Data System (ADS)

    Dayeh, M. A.; Evans, N. D.; Fuselier, S. A.; Trevino, J.; Ramaekers, J.; Dwyer, J. R.; Lucia, R.; Rassoul, H. K.; Kotovsky, D. A.; Jordan, D. M.; Uman, M. A.

    2015-07-01

    An acoustic camera comprising a linear microphone array is used to image the thunder signature of triggered lightning. Measurements were taken at the International Center for Lightning Research and Testing in Camp Blanding, FL, during the summer of 2014. The array was positioned in an end-fire orientation thus enabling the peak acoustic reception pattern to be steered vertically with a frequency-dependent spatial resolution. On 14 July 2014, a lightning event with nine return strokes was successfully triggered. We present the first acoustic images of individual return strokes at high frequencies (>1 kHz) and compare the acoustically inferred profile with optical images. We find (i) a strong correlation between the return stroke peak current and the radiated acoustic pressure and (ii) an acoustic signature from an M component current pulse with an unusual fast rise time. These results show that acoustic imaging enables clear identification and quantification of thunder sources as a function of lightning channel altitude.

  18. What Is an Acoustic Neuroma

    MedlinePlus

    ... Acoustic Neuroma An acoustic neuroma, also called a vestibular schwannoma, is a rare benign tumor of the ... Acoustic Neuroma? An acoustic neuroma, known as a vestibular schwannoma, is a benign (non-cancerous) growth that ...

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

    NASA Astrophysics Data System (ADS)

    Shen, Jian Qi

    2016-08-01

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

  20. Acoustic transmitters for underwater neutrino telescopes.

    PubMed

    Ardid, Miguel; Martínez-Mora, Juan A; Bou-Cabo, Manuel; Larosa, Giuseppina; Adrián-Martínez, Silvia; Llorens, Carlos D

    2012-01-01

    In this paper acoustic transmitters that were developed for use in underwater neutrino telescopes are presented. Firstly, an acoustic transceiver has been developed as part of the acoustic positioning system of neutrino telescopes. These infrastructures are not completely rigid and require a positioning system in order to monitor the position of the optical sensors which move due to sea currents. To guarantee a reliable and versatile system, the transceiver has the requirements of reduced cost, low power consumption, high pressure withstanding (up to 500 bars), high intensity for emission, low intrinsic noise, arbitrary signals for emission and the capacity of acquiring and processing received signals. Secondly, a compact acoustic transmitter array has been developed for the calibration of acoustic neutrino detection systems. The array is able to mimic the signature of ultra-high-energy neutrino interaction in emission directivity and signal shape. The technique of parametric acoustic sources has been used to achieve the proposed aim. The developed compact array has practical features such as easy manageability and operation. The prototype designs and the results of different tests are described. The techniques applied for these two acoustic systems are so powerful and versatile that may be of interest in other marine applications using acoustic transmitters. PMID:22666022

  1. Acoustic Transmitters for Underwater Neutrino Telescopes

    PubMed Central

    Ardid, Miguel; Martínez-Mora, Juan A.; Bou-Cabo, Manuel; Larosa, Giuseppina; Adrián-Martínez, Silvia; Llorens, Carlos D.

    2012-01-01

    In this paper acoustic transmitters that were developed for use in underwater neutrino telescopes are presented. Firstly, an acoustic transceiver has been developed as part of the acoustic positioning system of neutrino telescopes. These infrastructures are not completely rigid and require a positioning system in order to monitor the position of the optical sensors which move due to sea currents. To guarantee a reliable and versatile system, the transceiver has the requirements of reduced cost, low power consumption, high pressure withstanding (up to 500 bars), high intensity for emission, low intrinsic noise, arbitrary signals for emission and the capacity of acquiring and processing received signals. Secondly, a compact acoustic transmitter array has been developed for the calibration of acoustic neutrino detection systems. The array is able to mimic the signature of ultra-high-energy neutrino interaction in emission directivity and signal shape. The technique of parametric acoustic sources has been used to achieve the proposed aim. The developed compact array has practical features such as easy manageability and operation. The prototype designs and the results of different tests are described. The techniques applied for these two acoustic systems are so powerful and versatile that may be of interest in other marine applications using acoustic transmitters. PMID:22666022

  2. Simplified Processing Method for Meter Data Analysis

    SciTech Connect

    Fowler, Kimberly M.; Colotelo, Alison H. A.; Downs, Janelle L.; Ham, Kenneth D.; Henderson, Jordan W.; Montgomery, Sadie A.; Vernon, Christopher R.; Parker, Steven A.

    2015-11-01

    Simple/Quick metered data processing method that can be used for Army Metered Data Management System (MDMS) and Logistics Innovation Agency data, but may also be useful for other large data sets. Intended for large data sets when analyst has little information about the buildings.

  3. Evaluating Metal Probe Meters for Soil Testing.

    ERIC Educational Resources Information Center

    Hershey, David R.

    1992-01-01

    Inexpensive metal probe meters that are sold by garden stores can be evaluated by students for their accuracy in measuring soil pH, moisture, fertility, and salinity. The author concludes that the meters are inaccurate and cannot be calibrated in standard units. However, the student evaluations are useful in learning the methods of soil analysis…

  4. Physiological correlates to 800 meter running performance.

    PubMed

    Deason, J; Powers, S K; Lawler, J; Ayers, D; Stuart, M K

    1991-12-01

    Much of the previous research efforts aimed at determining those physiological characteristics that contribute to distance running success have centered around distances greater than 1500 meters with little attention to events such as the 800 meter run. Therefore, this investigation examined the relationship between selected physiological and body composition, characteristics and performance in an 800 meter run. Measurements of body composition, VO2max, running economy, and performance times for 100 and 300 meter dashes were obtained on 11 male track athletes. Stepwise multiple regression analysis was performed using 800 meter race time as the dependent variable. Although the combination of 300 and 100 meter run times, percent body fat, running economy and VO2 max as independent variables accounted for the greatest amount of total variance (r2 = .89), the additional variance explained by the model did not increase significantly (p greater than 0.05), when VO2max, percent body fat, and running economy were added to a model which contained 300 and 100 meter run time (r2 = .85) as the explanatory variables. These data offer additional support for the notion that much of the intramuscular ATP produce and utilized during an 800 meter run comes from anaerobic metabolic pathway. PMID:1806725

  5. Proton recoil scintillator neutron rem meter

    DOEpatents

    Olsher, Richard H.; Seagraves, David T.

    2003-01-01

    A neutron rem meter utilizing proton recoil and thermal neutron scintillators to provide neutron detection and dose measurement. In using both fast scintillators and a thermal neutron scintillator the meter provides a wide range of sensitivity, uniform directional response, and uniform dose response. The scintillators output light to a photomultiplier tube that produces an electrical signal to an external neutron counter.

  6. Symptoms of Acoustic Neuroma

    MedlinePlus

    ... Watch and Wait Radiation Microsurgery Acoustic Neuroma Decision Tree Questions for Your Physician Questions to Ask Yourself ... Watch and Wait Radiation Microsurgery Acoustic Neuroma Decision Tree Questions for Your Physician Questions to Ask Yourself ...

  7. Influence of the outer scales of temperature and dynamic turbulence on the characteristics of transmitted acoustic radiation

    NASA Astrophysics Data System (ADS)

    Shamanaeva, L. G.; Belov, V. V.; Burkatovskaya, Yu. B.; Krasnenko, N. P.

    2015-11-01

    In the present work, the problem of propagation of monochromatic acoustic radiation in the lower 500-meter layer of the plain stratified moving turbulent atmosphere is solved by the Monte Carlo method. The influence of the parameters of models of the outer scales of temperature and dynamic turbulence on the intensity of transmitted acoustic radiation intensity is investigated.

  8. Performance of ice meter and weight assemblies

    USGS Publications Warehouse

    Schneider, V.R.; Futrell, J.C.

    1984-01-01

    The performance of three ice meters and weight assemblies used by the U.S. Geological Survey and Environment Canada were compared in a towing tank. Each meter was rated individually on a rod suspension and then rerated on a cable suspension, with the appropriate weight assembly. Vertical and veer cable angles were measured along with meter yaw angle. The effect of the weight assembly on the rod-suspension rating for each meter was illustrated by computing a correction coefficient which ranged between 0.88 and 1.10 depending on the weight system used and the fluid velocity. A sluch-n-all type weight assembly least affected the meter rating and was the most stable in all flow conditions. (USGS)

  9. Acoustic emission frequency discrimination

    NASA Technical Reports Server (NTRS)

    Sugg, Frank E. (Inventor); Graham, Lloyd J. (Inventor)

    1988-01-01

    In acoustic emission nondestructive testing, broadband frequency noise is distinguished from narrow banded acoustic emission signals, since the latter are valid events indicative of structural flaws in the material being examined. This is accomplished by separating out those signals which contain frequency components both within and beyond (either above or below) the range of valid acoustic emission events. Application to acoustic emission monitoring during nondestructive bond verification and proof loading of undensified tiles on the Space Shuttle Orbiter is considered.

  10. The effects of meter orientation downstream of a short radius elbow on electromagnetic flow meters

    NASA Astrophysics Data System (ADS)

    Justensen, Jared C.

    Electromagnetic flowmeters (known as magnetic flow meters) are a widely used type of flowmeter. The accuracy of magnetic flow meters are a function of several factors, not the least of which is the flow condition inside the pipe. It has been shown that disturbances in the velocity profile affects the accuracy of a magnetic flow meter (Luntta, 1998). Accordingly, manufacturers of magnetic flow meters give installation guidelines. These guidelines help prevent the user from installing the meter in a pipe configuration that is likely to cause the meter to produce inaccurate results. Although most manufacturers provide recommendations about the amount of straight pipe that is necessary upstream of the meter, little is said about the orientation of the meter in relation to upstream disturbances. This study examines the performance of magnetic flow meters when positioned at two different orientations: EIP (electrodes in plane with an upstream 90-degree short radius elbow) and EOP (electrodes out of plane). Four different meters were included in the study in which a baseline straight pipe test was first performed using over fifty diameters of straight pipe upstream of each meter. The straight pipe test was used to determine the baseline accuracy of each of the meters over a velocity range that is typical for the size and function of the meters. Meters were then installed at five different locations downstream from a 90-degree short-radius elbow. At each location the meters were tested in two orientations at five different flow rates. The intent of the research is to show that the orientation of a magnetic flow meter affects the meter's ability to produce accurate flow readings when it is installed downstream of a flow disturbance. The results from this research showed a significant shift in measurement accuracy when the meter was in EIP and EOP orientations. All of the meters in the study produced accuracy readings at one point of another that were outside the specified

  11. Acoustic spin pumping in magnetoelectric bulk acoustic wave resonator

    NASA Astrophysics Data System (ADS)

    Polzikova, N. I.; Alekseev, S. G.; Pyataikin, I. I.; Kotelyanskii, I. M.; Luzanov, V. A.; Orlov, A. P.

    2016-05-01

    We present the generation and detection of spin currents by using magnetoelastic resonance excitation in a magnetoelectric composite high overtone bulk acoustic wave (BAW) resonator (HBAR) formed by a Al-ZnO-Al-GGG-YIG-Pt structure. Transversal BAW drives magnetization oscillations in YIG film at a given resonant magnetic field, and the resonant magneto-elastic coupling establishes the spin-current generation at the Pt/YIG interface. Due to the inverse spin Hall effect (ISHE) this BAW-driven spin current is converted to a dc voltage in the Pt layer. The dependence of the measured voltage both on magnetic field and frequency has a resonant character. The voltage is determined by the acoustic power in HBAR and changes its sign upon magnetic field reversal. We compare the experimentally observed amplitudes of the ISHE electrical field achieved by our method and other approaches to spin current generation that use surface acoustic waves and microwave resonators for ferromagnetic resonance excitation, with the theoretically expected values.

  12. Acoustic source localization.

    PubMed

    Kundu, Tribikram

    2014-01-01

    In this article different techniques for localizing acoustic sources are described and the advantages/disadvantages of these techniques are discussed. Some source localization techniques are restricted to isotropic structures while other methods can be applied to anisotropic structures as well. Some techniques require precise knowledge of the direction dependent velocity profiles in the anisotropic body while other techniques do not require that knowledge. Some methods require accurate values of the time of arrival of the acoustic waves at the receivers while other techniques can function without that information. Published papers introducing various techniques emphasize the advantages of the introduced techniques while ignoring and often not mentioning the limitations and weaknesses of the new techniques. What is lacking in the literature is a comprehensive review and comparison of the available techniques; this article attempts to do that. After reviewing various techniques the paper concludes which source localization technique should be most effective for what type of structure and what the current research needs are. PMID:23870388

  13. 46 CFR 28.345 - Electrical standards for vessels less than 79 feet (24 meters) in length.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... section, the vessel may comply with the requirements of 33 CFR part 183, subpart I and § 28.370. ... than 79 feet (24 meters) in length with an alternating current electrical distribution system may... meters) in length with a direct current system may comply with the requirements of ABYC E-1, ABYC...

  14. 46 CFR 28.345 - Electrical standards for vessels less than 79 feet (24 meters) in length.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... section, the vessel may comply with the requirements of 33 CFR part 183, subpart I and § 28.370. ... than 79 feet (24 meters) in length with an alternating current electrical distribution system may... meters) in length with a direct current system may comply with the requirements of ABYC E-1, ABYC...

  15. Acoustic Location of Lightning Using Interferometric Techniques

    NASA Astrophysics Data System (ADS)

    Erives, H.; Arechiga, R. O.; Stock, M.; Lapierre, J. L.; Edens, H. E.; Stringer, A.; Rison, W.; Thomas, R. J.

    2013-12-01

    Acoustic arrays have been used to accurately locate thunder sources in lightning flashes. The acoustic arrays located around the Magdalena mountains of central New Mexico produce locations which compare quite well with source locations provided by the New Mexico Tech Lightning Mapping Array. These arrays utilize 3 outer microphones surrounding a 4th microphone located at the center, The location is computed by band-passing the signal to remove noise, and then computing the cross correlating the outer 3 microphones with respect the center reference microphone. While this method works very well, it works best on signals with high signal to noise ratios; weaker signals are not as well located. Therefore, methods are being explored to improve the location accuracy and detection efficiency of the acoustic location systems. The signal received by acoustic arrays is strikingly similar to th signal received by radio frequency interferometers. Both acoustic location systems and radio frequency interferometers make coherent measurements of a signal arriving at a number of closely spaced antennas. And both acoustic and interferometric systems then correlate these signals between pairs of receivers to determine the direction to the source of the received signal. The primary difference between the two systems is the velocity of propagation of the emission, which is much slower for sound. Therefore, the same frequency based techniques that have been used quite successfully with radio interferometers should be applicable to acoustic based measurements as well. The results presented here are comparisons between the location results obtained with current cross correlation method and techniques developed for radio frequency interferometers applied to acoustic signals. The data were obtained during the summer 2013 storm season using multiple arrays sensitive to both infrasonic frequency and audio frequency acoustic emissions from lightning. Preliminary results show that

  16. Investigation of reverberation synthesized by electro-acoustic enhancement systems, from a subjective and physical acoustic standpoint

    NASA Astrophysics Data System (ADS)

    Shimizu, Yasushi

    2002-05-01

    Current electro-acoustic enhancement technology enables wide control over concert hall acoustics. The goal of sound field synthesis in anechoic space is to reconstruct a specific sound field. However, applying acoustic enhancement technology to existing reverberant spaces is a less developed research direction. This presentation demonstrates a methodology of electro-acoustic enhancement using regenerative reverberation through SAAF (spatially averaged acoustic feedback), an acceptable variation of RT and SPL in enhanced acoustical conditions. That was presented by YAMAHA Acoustic Research Laboratories. SAAF technology can flatten amplitude peaks at the howling frequency of acoustical feedback loops by using time variant finite impulse response filters. Therefore it enables regeneration of reverberated sound by wide band feedback in frequency without coloration. This system has been applied to ``negative absorption control'' and loudness equalization of under-balcony seats in current concert halls, to optimize concert hall acoustics electronically instead of architecturally. Adjusted reverberation time in enhanced condition should be between 1.5 and 2.0 times higher than the natural RT (ex. RTon/Rtoff=1.8). The SPL increases about 1 dB to 3 dB based on measured results of more than 30 performing halls integrated with acoustic enhancement system in Japan. Examples of the major Japanese concert halls with acoustic enhancement systems are presented.

  17. Acoustic effects of sprays

    NASA Technical Reports Server (NTRS)

    Pindera, Maciej Z.; Przekwas, Andrzej J.

    1994-01-01

    Since the early 1960's, it has been known that realistic combustion models for liquid fuel rocket engines should contain at least a rudimentary treatment of atomization and spray physics. This is of particular importance in transient operations. It has long been recognized that spray characteristics and droplet vaporization physics play a fundamental role in determining the stability behavior of liquid fuel rocket motors. This paper gives an overview of work in progress on design of a numerical algorithm for practical studies of combustion instabilities in liquid rocket motors. For flexibility, the algorithm is composed of semi-independent solution modules, accounting for different physical processes. Current findings are report and future work is indicated. The main emphasis of this research is the development of an efficient treatment to interactions between acoustic fields and liquid fuel/oxidizer sprays.

  18. Wind turbine acoustic standards

    NASA Technical Reports Server (NTRS)

    Stephens, D. G.; Shepherd, K. P.; Grosveld, F.

    1981-01-01

    A program is being conducted to develop noise standards for wind turbines which minimize annoyance and which can be used to design specifications. The approach consists of presenting wind turbine noise stimuli to test subjects in a laboratory listening chamber. The responses of the subjects are recorded for a range of stimuli which encompass the designs, operating conditions, and ambient noise levels of current and future installations. Results to date have established the threshold of detectability for a range of impulsive stimuli of the type associated with blade/tower wake interactions. The status of the ongoing psychoacoustic tests, the subjective data, and the approach to the development of acoustic criteria/standards are described.

  19. Intercomparison tests of moored current measurements in the upper ocean

    NASA Astrophysics Data System (ADS)

    Halpern, David; Weller, Robert A.; Briscoe, Melbourne G.; Davis, Russ E.; McCullough, James R.

    1981-01-01

    During the August-September 1977 Mixed Layer Experiment (Mile) and the July-September 1978 Joint Air-Sea Interaction (Jasin) project, moored current measurements were made in the upper ocean with Savonius rotor and vane vector-averaging current meters (VACM), dual orthogonal propeller vector-measuring current meters (VMCM), and dual orthogonal acoustic travel-time vector-averaging current meters (ACM). Wind speeds and significant wave heights reached 20ms-1 and 5 m. The influence of mooring motion upon ACM, VACM, and VMCM measurements are described. In the mixed layer above about 30 m depth where mean currents are relatively large, the effect of a surface-following buoy upon ACM, VACM, and VMCM velocity fluctuations at frequencies less than 0.3 cph was negligible; at frequencies above 4 cph, the VACM data contained the largest amount of mooring induced contamination. Below the mixed layer at depths greater than about 75 m, a subsurface mooring should be used; however, when a surface-following buoy was used, then VMCM data better approximated the spectrum of the fluctuations than VACM data. A spar-buoy should not be used to measure currents at depths as deep as 80 m. The frequency-dependent differences between VACM and VMCM and between VACM and ACM measurements are described. At frequencies less than 0.3 cph, the differences between the VACM and ACM or the VMCM records were not significant with 95% confidence limits, were always positive, and above 80 m depth were less than 20%. At frequencies above 4 cph, the VACM-VMCM differences were about 5 times larger than the VACM-ACM differences.

  20. Calibration of water-velocity meters

    USGS Publications Warehouse

    Kaehrle, William R.; Bowie, James E.

    1988-01-01

    The U.S. Geological Survey, Department of the Interior, as part of its responsibility to appraise the quantity of water resources in the United States, maintains facilities for the calibration of water-velocity meters at the Gulf Coast Hydroscience Center's Hydraulic Laboratory Facility, NSTL, Mississippi. These meters are used in hydrologic studies by the Geological Survey, U.S. Army Corps of Engineers, U.S. Department of Energy, state agencies, universities, and others in the public and private sector. This paper describes calibration facilities, types of water-velocity meters calibrated, and calibration standards, methods and results.

  1. A synthetic aperture acoustic prototype system

    NASA Astrophysics Data System (ADS)

    Luke, Robert H.; Bishop, Steven S.; Chan, Aaron M.; Gugino, Peter M.; Donzelli, Thomas P.; Soumekh, Mehrdad

    2015-05-01

    A novel quasi-monostatic system operating in a side-scan synthetic aperture acoustic (SAA) imaging mode is presented. This research project's objectives are to explore the military utility of outdoor continuous sound imaging of roadside foliage and target detection. The acoustic imaging method has several military relevant advantages such as being immune to RF jamming, superior spatial resolution as compared to 0.8-2.4 GHz ground penetrating radar (GPR), capable of standoff side and forward-looking scanning, and relatively low cost, weight and size when compared to GPR technologies. The prototype system's broadband 2-17 kHz LFM chirp transceiver is mounted on a manned all-terrain vehicle. Targets are positioned within the acoustic main beam at slant ranges of two to seven meters and on surfaces such as dirt, grass, gravel and weathered asphalt and with an intervening metallic chain link fence. Acoustic image reconstructions and signature plots result in means for literal interpretation and quantifiable analyses.

  2. The smart meter and a smarter consumer: quantifying the benefits of smart meter implementation in the United States

    PubMed Central

    2012-01-01

    The electric grid in the United States has been suffering from underinvestment for years, and now faces pressing challenges from rising demand and deteriorating infrastructure. High congestion levels in transmission lines are greatly reducing the efficiency of electricity generation and distribution. In this paper, we assess the faults of the current electric grid and quantify the costs of maintaining the current system into the future. While the proposed “smart grid” contains many proposals to upgrade the ailing infrastructure of the electric grid, we argue that smart meter installation in each U.S. household will offer a significant reduction in peak demand on the current system. A smart meter is a device which monitors a household’s electricity consumption in real-time, and has the ability to display real-time pricing in each household. We conclude that these devices will provide short-term and long-term benefits to utilities and consumers. The smart meter will enable utilities to closely monitor electricity consumption in real-time, while also allowing households to adjust electricity consumption in response to real-time price adjustments. PMID:22540990

  3. The smart meter and a smarter consumer: quantifying the benefits of smart meter implementation in the United States.

    PubMed

    Cook, Brendan; Gazzano, Jerrome; Gunay, Zeynep; Hiller, Lucas; Mahajan, Sakshi; Taskan, Aynur; Vilogorac, Samra

    2012-01-01

    The electric grid in the United States has been suffering from underinvestment for years, and now faces pressing challenges from rising demand and deteriorating infrastructure. High congestion levels in transmission lines are greatly reducing the efficiency of electricity generation and distribution. In this paper, we assess the faults of the current electric grid and quantify the costs of maintaining the current system into the future. While the proposed "smart grid" contains many proposals to upgrade the ailing infrastructure of the electric grid, we argue that smart meter installation in each U.S. household will offer a significant reduction in peak demand on the current system. A smart meter is a device which monitors a household's electricity consumption in real-time, and has the ability to display real-time pricing in each household. We conclude that these devices will provide short-term and long-term benefits to utilities and consumers. The smart meter will enable utilities to closely monitor electricity consumption in real-time, while also allowing households to adjust electricity consumption in response to real-time price adjustments. PMID:22540990

  4. Advanced optical smoke meters for jet engine exhaust measurement

    NASA Technical Reports Server (NTRS)

    Pitz, R. W.

    1986-01-01

    Smoke meters with increased sensitivity, improved accuracy, and rapid response are needed to measure the smoke levels emitted by modern jet engines. The standard soiled tape meter in current use is based on filtering, which yields long term averages and is insensitive to low smoke levels. Two new optical smoke meter techniques that promise to overcome these difficulties have been experimentally evaluated: modulated transmission (MODTRAN) and photothermal deflection spectroscopy (PDS). Both techniques are based on light absorption by smoke, which is closely related to smoke density. They are variations on direct transmission measurements which produce a modulated signal that can be easily measured with phase sensitive detection. The MODTRAN and PDS techniques were tested on low levels of smoke and diluted samples of NO2 in nitrogen, simulating light adsorption due to smoke. The results are evaluated against a set of ideal smoke meter criteria that include a desired smoke measurement range of 0.1 to 12 mg cu.m. (smoke numbers of 1 to 50) and a frequency response of 1 per second. The MODTRAN instrument is found to be inaccurate for smoke levels below 3 mg/cu.m. and is able to make a only about once every 20 seconds because of its large sample cell. The PDS instrument meets nearly all the characteristics of an ideal smoke meter: it has excellent sensitivity over a range of smoke levels from 0.1 to 20 mg/cu.m. (smoke numbers of 1 to 60) and good frequency response (1 per second).

  5. Longitudinal bulk acoustic mass sensor

    SciTech Connect

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

    2009-07-20

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

  6. Solid Rocket Motor Acoustic Testing

    SciTech Connect

    Rogers, J.D.

    1999-03-31

    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.

  7. Feasibility of Estimating Constituent Concentrations and Loads Based on Data Recorded by Acoustic Instrumentation

    USGS Publications Warehouse

    Lietz, A.C.

    2002-01-01

    The acoustic Doppler current profiler (ADCP) and acoustic Doppler velocity meter (ADVM) were used to estimate constituent concentrations and loads at a sampling site along the Hendry-Collier County boundary in southwestern Florida. The sampling site is strategically placed within a highly managed canal system that exhibits low and rapidly changing water conditions. With the ADCP and ADVM, flow can be gaged more accurately rather than by conventional field-data collection methods. An ADVM velocity rating relates measured velocity determined by the ADCP (dependent variable) with the ADVM velocity (independent variable) by means of regression analysis techniques. The coefficient of determination (R2) for this rating is 0.99 at the sampling site. Concentrations and loads of total phosphorus, total Kjeldahl nitrogen, and total nitrogen (dependent variables) were related to instantaneous discharge, acoustic backscatter, stage, or water temperature (independent variables) recorded at the time of sampling. Only positive discharges were used for this analysis. Discharges less than 100 cubic feet per second generally are considered inaccurate (probably as a result of acoustic ray bending and vertical temperature gradients in the water column). Of the concentration models, only total phosphorus was statistically significant at the 95-percent confidence level (p-value less than 0.05). Total phosphorus had an adjusted R2 of 0.93, indicating most of the variation in the concentration can be explained by the discharge. All of the load models for total phosphorus, total Kjeldahl nitrogen, and total nitrogen were statistically significant. Most of the variation in load can be explained by the discharge as reflected in the adjusted R2 for total phosphorus (0.98), total Kjeldahl nitrogen (0.99), and total nitrogen (0.99).

  8. Magneto acoustic emission apparatus for testing materials for embrittlement

    NASA Technical Reports Server (NTRS)

    Allison, Sidney G. (Inventor); Min, Namkung (Inventor); Yost, William T. (Inventor); Cantrell, John H. (Inventor)

    1990-01-01

    A method and apparatus for testing steel components for temper embrittlement uses magneto-acoustic emission to nondestructively evaluate the component. Acoustic emission signals occur more frequently at higher levels in embrittled components. A pair of electromagnets are used to create magnetic induction in the test component. Magneto-acoustic emission signals may be generated by applying an ac current to the electromagnets. The acoustic emission signals are analyzed to provide a comparison between a component known to be unembrittled and a test component. Magnetic remanence is determined by applying a dc current to the electromagnets, then turning the magnets off and observing the residual magnetic induction.

  9. Advanced smoke meter development survey and analysis

    NASA Technical Reports Server (NTRS)

    Pitz, R. W.; Penney, C. M.; Stanforth, C. M.; Shaffernocker, W. M.

    1984-01-01

    Ideal smoke meter characteristics are determined to provide a basis for evaluation of candidate systems. Five promising techniques are analyzed in detail to evaluate compilance with the practical smoke meter requirements. Four of the smoke measurement concepts are optical methods: Modulated Transmission (MODTRAN), Cross Beam Absorption Counter (CBAC), Laser Induced Incandescence (LIN), and Photoacoustic Spectroscopy (PAS). A rapid response filter instrument called a Taper Element Oscillating Microbalance (TEOM) is also evaluated. For each technique, the theoretical principles are described, the expected performance is determined, and the advantages and disadvantages are discussed The expected performance is evaluated against each of the smoke meter specifications, and the key questions for further study are given. The most promising smoke meter technique analyzed was MODTRAN, which is a variation on a direct transmission measurement. The soot-laden gas is passed through a transmission cell, and the gas pressure is modulated by a speaker.

  10. Continuous flow measurements using fixed ultrasonic meters

    USGS Publications Warehouse

    Oltmann, Rick

    1993-01-01

    USGS has or soon will be installing four continuous flow-monitoring stations in the delta that will use ultrasonic velocity meters (DVM). Funding for the stations has been provided by USGS, DWR, USBR, and Contra Costa Water District.

  11. Advanced metering techniques in the federal sector

    SciTech Connect

    Szydlowski, R.F.; Chvala, W.D. Jr.; Halverson, M.A.

    1994-12-01

    The lack of utility metering in the federal sector has hampered introduction of direct billing of individual activities at most military installations. Direct billing will produce accountability for the amount of energy used and is a positive step toward self-directed energy conservation. For many installations, automatic meter reading (AMR) is a cost-effective way to increase the number of meters while reducing labor requirements and providing energy conservation analysis capabilities. The communications technology used by some of the AMR systems provides other demand-side management (DSM) capabilities. This paper summarizes the characteristics and relative merits of several AMR/DSM technologies that may be appropriate for the federal sector. A case study of an AMR system being installed at Fort Irwin, California, describes a cost-effective two-way radio communication system used for meter reading and load control.

  12. The new 34-meter antenna

    NASA Technical Reports Server (NTRS)

    Pompa, M. F.

    1986-01-01

    The new 34-m high efficiency Azimuth - Elevation antenna configuration, including its features, dynamic characteristics and performance at 8.4-GHz frequencies is described. The current-technology features of this antenna produce a highly reliable configuration by incorporation of a main wheel and track azimuth support, central pintle pivot bearing, close tolerance surface panels and all-welded construction. Also described are basic drive controls that, as slaved to three automatic microprocessors, provide accurate and safe control of the antenna's steering tasks. At this time antenna installations are completed at Goldstone and Canberra and have operationally supported the Voyager - Uranus encounter. A third installation is being constructed currently in Madrid and is scheduled for completion in late 1986.

  13. The new 34-meter antenna

    NASA Astrophysics Data System (ADS)

    Pompa, M. F.

    1986-05-01

    The new 34-m high efficiency Azimuth - Elevation antenna configuration, including its features, dynamic characteristics and performance at 8.4-GHz frequencies is described. The current-technology features of this antenna produce a highly reliable configuration by incorporation of a main wheel and track azimuth support, central pintle pivot bearing, close tolerance surface panels and all-welded construction. Also described are basic drive controls that, as slaved to three automatic microprocessors, provide accurate and safe control of the antenna's steering tasks. At this time antenna installations are completed at Goldstone and Canberra and have operationally supported the Voyager - Uranus encounter. A third installation is being constructed currently in Madrid and is scheduled for completion in late 1986.

  14. Ampere-Hour Meter For Rechargeable Battery

    NASA Technical Reports Server (NTRS)

    Tripp, John S.; Schott, Timothy D.; Tcheng, Ping

    1993-01-01

    Low-power analog/digital electronic circuit meters discharge of storage battery in ampere-hours. By metering discharge, one obtains indication of state of charge of battery and avoids unnecessary recharging, maintaining capacity of battery and prolonging life. Because of its small size and low power consumption, useful in such applications as portable video cameras, communication equipment on boats, portable audio equipment, and portable medical equipment.

  15. AST Launch Vehicle Acoustics

    NASA Technical Reports Server (NTRS)

    Houston, Janice; Counter, D.; Giacomoni, D.

    2015-01-01

    The liftoff phase induces acoustic loading over a broad frequency range for a launch vehicle. These external acoustic environments are then used in the prediction of internal vibration responses of the vehicle and components which result in the qualification levels. Thus, predicting these liftoff acoustic (LOA) environments is critical to the design requirements of any launch vehicle. If there is a significant amount of uncertainty in the predictions or if acoustic mitigation options must be implemented, a subscale acoustic test is a feasible pre-launch test option to verify the LOA environments. The NASA Space Launch System (SLS) program initiated the Scale Model Acoustic Test (SMAT) to verify the predicted SLS LOA environments and to determine the acoustic reduction with an above deck water sound suppression system. The SMAT was conducted at Marshall Space Flight Center and the test article included a 5% scale SLS vehicle model, tower and Mobile Launcher. Acoustic and pressure data were measured by approximately 250 instruments. The SMAT liftoff acoustic results are presented, findings are discussed and a comparison is shown to the Ares I Scale Model Acoustic Test (ASMAT) results.

  16. Acoustic Translation of an Acoustically Levitated Sample

    NASA Technical Reports Server (NTRS)

    Barmatz, M. B.; Allen, J. L.

    1986-01-01

    Acoustic-levitation apparatus uses only one acoustic mode to move sample from one region of chamber to another. Sample heated and cooled quickly by translation between hot and cold regions of levitation chamber. Levitated sample is raised into furnace region by raising plunger. Frequency of sound produced by transducers adjusted by feedback system to maintain (102) resonant mode, which levitates sample midway between transducers and plunger regardless of plunger position.

  17. The Development of the Acoustic Design of NASA Glenn Research Center's New Reverberant Acoustic Test Facility

    NASA Technical Reports Server (NTRS)

    Hughes, William O.; McNelis, Mark E.; Hozman, Aron D.; McNelis, Anne M.

    2011-01-01

    The National Aeronautics and Space Administration (NASA) Glenn Research Center (GRC) is leading the design and build of the new world-class vibroacoustic test capabilities at the NASA GRC's Plum Brook Station in Sandusky, Ohio, USA. Benham Companies, LLC is currently constructing modal, base-shake sine and reverberant acoustic test facilities to support the future testing needs of NASA s space exploration program. The large Reverberant Acoustic Test Facility (RATF) will be approximately 101,000 ft3 in volume and capable of achieving an empty chamber acoustic overall sound pressure level (OASPL) of 163 dB. This combination of size and acoustic power is unprecedented amongst the world s known active reverberant acoustic test facilities. The key to achieving the expected acoustic test spectra for a range of many NASA space flight environments in the RATF is the knowledge gained from a series of ground acoustic tests. Data was obtained from several NASA-sponsored test programs, including testing performed at the National Research Council of Canada s acoustic test facility in Ottawa, Ontario, Canada, and at the Redstone Technical Test Center acoustic test facility in Huntsville, Alabama, USA. The majority of these tests were performed to characterize the acoustic performance of the modulators (noise generators) and representative horns that would be required to meet the desired spectra, as well as to evaluate possible supplemental gas jet noise sources. The knowledge obtained in each of these test programs enabled the design of the RATF sound generation system to confidently advance to its final acoustic design and subsequent on-going construction.

  18. The Development of the Acoustic Design of NASA Glenn Research Center's New Reverberant Acoustic Test Facility

    NASA Technical Reports Server (NTRS)

    Hughes, William O.; McNelis, Mark E.; Hozman, Aron D.; McNelis, Anne M.

    2011-01-01

    The National Aeronautics and Space Administration (NASA) Glenn Research Center (GRC) is leading the design and build of the new world-class vibroacoustic test capabilities at the NASA GRC s Plum Brook Station in Sandusky, Ohio. Benham Companies, LLC is currently constructing modal, base-shake sine and reverberant acoustic test facilities to support the future testing needs of NASA s space exploration program. The large Reverberant Acoustic Test Facility (RATF) will be approximately 101,000 ft3 in volume and capable of achieving an empty chamber acoustic overall sound pressure level (OASPL) of 163 dB. This combination of size and acoustic power is unprecedented amongst the world s known active reverberant acoustic test facilities. The key to achieving the expected acoustic test spectra for a range of many NASA space flight environments in the RATF is the knowledge gained from a series of ground acoustic tests. Data was obtained from several NASA-sponsored test programs, including testing performed at the National Research Council of Canada s acoustic test facility in Ottawa, Ontario, Canada, and at the Redstone Technical Test Center acoustic test facility in Huntsville, Alabama. The majority of these tests were performed to characterize the acoustic performance of the modulators (noise generators) and representative horns that would be required to meet the desired spectra, as well as to evaluate possible supplemental gas jet noise sources. The knowledge obtained in each of these test programs enabled the design of the RATF sound generation system to confidently advance to its final acoustic design and subsequent on-going construction.

  19. Low-cost cell-phone-based digital lux meter

    NASA Astrophysics Data System (ADS)

    Sumriddetchkajorn, Sarun; Somboonkaew, Armote

    2010-11-01

    The amount of light is an important issue in several scenarios ranging from scenic design, light pollution study, illumination engineering, and agriculture. It is typically determined by using a portable digital light or lux meter. By realizing that the proliferation of cell phones is currently tremendous, this paper proposes for the first time a low-cost cell phone based digital light meter. Our innovative idea comes from the fact that the digital camera built into the cell phone is functioned as a two-dimensional light sensitive device and the captured image can be made diffuse. In this way, the diffused image is correlated to the corresponding light level by the built-in microprocessor of the cell phone and our specific algorithm embedded. Our experiment using a typical cell phone embedded with a digital camera and our JAVA program will be discussed.

  20. Simulations of a meter-long plasma wakefield accelerator

    SciTech Connect

    Lee, S.; Katsouleas, T.; Hemker, R.; Mori, W. B.

    2000-06-01

    Full-scale particle-in-cell simulations of a meter-long plasma wakefield accelerator (PWFA) are presented in two dimensions. The results support the design of a current PWFA experiment in the nonlinear blowout regime where analytic solutions are intractable. A relativistic electron bunch excites a plasma wake that accelerates trailing particles at rates of several hundred MeV/m. A comparison is made of various simulation codes, and a parallel object-oriented code OSIRIS is used to model a full meter of acceleration. Excellent agreement is obtained between the simulations and analytic expressions for the transverse betatron oscillations of the beam. The simulations are used to develop scaling laws for designing future multi-GeV accelerator experiments. (c) 2000 The American Physical Society.

  1. Surface acoustic wave devices as passive buried sensors

    NASA Astrophysics Data System (ADS)

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

    2011-02-01

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

  2. Plume 1400 Meters High Discovered at the Seafloor off the Northern California Margin

    NASA Astrophysics Data System (ADS)

    Gardner, James V.; Malik, Mashkoor; Walker, Sharon

    2009-08-01

    On 17 May 2009, the Kongsberg EM302 multibeam echo sounder on board the U.S. National Oceanic and Atmospheric Administration's (NOAA) Okeanos Explorer was collecting bathymetry and water column acoustic data offshore of northern California when it suddenly imaged a previously undiscovered 1400-meter-high plume (Figure 1) rising from the seafloor at 40°32.13'N, 124°47.01'W. The ship was mapping in water depths of approximately 1830 meters and heading east up the northern California continental margin 20 kilometers north of the Gorda escarpment. The continental shelf in this area is known to have subsurface and water column thermogenic and methane gas, although no plumes from this area previously have been reported from deeper than the continental shelf. The plume, which rises vertically 1000 meters before being deflected to the north, was recorded for approximately 5 minutes before it disappeared from the data. The recording was made at night, so the ship's bridge watch was not able to see any surface manifestations of the plume at that time. The plume is composed of individual streams of acoustic reflectors, best seen in a video assembled from the water column data (http://ccom.unh.edu/NOAA_oceanexploration). The digital terrain model created from the multibeam bathymetry shows that the plume rises from the base of a large, previously unknown, amphitheater-like failure.

  3. Perception of strong-meter and weak-meter rhythms in children with spina bifida meningomyelocele

    PubMed Central

    HOPYAN, TALAR; SCHELLENBERG, E. GLENN; DENNIS, MAUREEN

    2011-01-01

    Neurodevelopmental disorders such as spina bifida meningomyelocele (SBM) are often associated with dysrhythmic movement. We studied rhythm discrimination in 21 children with SBM and in 21 age-matched controls, with the research question being whether both groups showed a strong-meter advantage whereby rhythm discrimination is better for rhythms with a strong-meter, in which onsets of longer intervals occurred on the beat, than those with a weak-meter, in which onsets of longer intervals occurred off the beat. Compared to controls, the SBM group was less able to discriminate strong-meter rhythms, although they performed comparably in discriminating weak-meter rhythms. The attenuated strong-meter advantage in children with SBM shows that their rhythm deficits occur at the level of both perception and action, and may represent a central processing disruption of the brain mechanisms for rhythm. PMID:19573270

  4. Ground Layer Laser Seeing Meter

    NASA Astrophysics Data System (ADS)

    Cavazzani, S.; Rodeghiero, G.; Capraro, I.; Ortolani, S.; Barbieri, C.; Zitelli, V.

    2014-03-01

    The seeing calculation and its evolution during the night is a key point for the operation of telescopes and adaptive optics systems. Currently, there are various instruments able to measure the seeing, for example, the DIMM (differential image motion monitor) and the MASS (multi aperture scintillation sensor). This paper describes a new tool for the local ground layer seeing measurement. In particular, we want to derive the Fried parameter r0 through a laser beam horizontal propagation. This is a new method for the experimental study of low-altitude atmospheric turbulence. Finally, we sketch an experimental setup for the Asiago Ekar Observatory and its possible applications.

  5. Acoustic measurement method of the volume flux of a seafloor hydrothermal plume

    NASA Astrophysics Data System (ADS)

    Xu, G.; Jackson, D. R.; Bemis, K. G.; Rona, P. A.

    2011-12-01

    similar methodology but a different sonar system) provide references to the consistency of the methodology. Second, the vertical flow rate measurement made in 2007 at an adjacent vent complex (Dante) using a different acoustic method (acoustic scintillation) can serve as a first order estimation of the plume vertical velocity. Third, another first order estimation can be obtained by combining the plume bending angle with the horizontal current measured by a current meter array deployed to the north of the vent field. Finally, statistical techniques are used to quantify the errors due to the ambient noises, inherent uncertainties of the methodology, and the fluctuation of the plume structure.

  6. Relationships between objective acoustic indices and acoustic comfort evaluation in nonacoustic spaces

    NASA Astrophysics Data System (ADS)

    Kang, Jian

    2001-05-01

    Much attention has been paid to acoustic spaces such as concert halls and recording studios, whereas research on nonacoustic buildings/spaces has been rather limited, especially from the viewpoint of acoustic comfort. In this research a series of case studies has been carried out on this topic, considering various spaces including shopping mall atrium spaces, library reading rooms, football stadia, swimming spaces, churches, dining spaces, as well as urban open public spaces. The studies focus on the relationships between objective acoustic indices such as sound pressure level and reverberation time and perceptions of acoustic comfort. The results show that the acoustic atmosphere is an important consideration in such spaces and the evaluation of acoustic comfort may vary considerably even if the objective acoustic indices are the same. It is suggested that current guidelines and technical regulations are insufficient in terms of acoustic design of these spaces, and the relationships established from the case studies between objective and subjective aspects would be useful for developing further design guidelines. [Work supported partly by the British Academy.

  7. Nonlinear Acoustics in Fluids

    NASA Astrophysics Data System (ADS)

    Lauterborn, Werner; Kurz, Thomas; Akhatov, Iskander

    At high sound intensities or long propagation distances at in fluids sufficiently low damping acoustic phenomena become nonlinear. This chapter focuses on nonlinear acoustic wave properties in gases and liquids. The origin of nonlinearity, equations of state, simple nonlinear waves, nonlinear acoustic wave equations, shock-wave formation, and interaction of waves are presented and discussed. Tables are given for the nonlinearity parameter B/A for water and a range of organic liquids, liquid metals and gases. Acoustic cavitation with its nonlinear bubble oscillations, pattern formation and sonoluminescence (light from sound) are modern examples of nonlinear acoustics. The language of nonlinear dynamics needed for understanding chaotic dynamics and acoustic chaotic systems is introduced.

  8. Effects of Liner Geometry on Acoustic Impedance

    NASA Technical Reports Server (NTRS)

    Jones, Michael G.; Tracy, Maureen B.; Watson, Willie R.; Parrott, Tony L.

    2002-01-01

    Current aircraft engine nacelles typically contain acoustic liners consisting of perforated sheets bonded onto honeycomb cavities. Numerous models have been developed to predict the acoustic impedance of these liners in the presence of grazing flow, and to use that information with aeroacoustic propagation codes to assess nacelle liner noise suppression. Recent efforts have provided advances in impedance education methodologies that offer more accurate determinations of acoustic liner properties in the presence of grazing flow. The current report provides the results of a parametric study, in which a finite element method was used to assess the effects of variations of the following geometric parameters on liner impedance, with and without the presence of grazing flow: percent open area, sheet thickness, sheet thickness-to-hole diameter ratio and cavity depth. Normal incidence acoustic impedances were determined for eight acoustic liners, consisting of punched aluminum facesheets bonded to hexcell honeycomb cavities. Similar liners were tested in the NASA Langley Research Center grazing incidence tube to determine their response in the presence of grazing flow. The resultant data provide a quantitative assessment of the effects of these perforate, single-layer liner parameters on the acoustic impedance of the liner.

  9. Acoustic design of the QCSEE propulsion systems

    NASA Technical Reports Server (NTRS)

    Loeffler, I. J.; Smith, E. B.; Sowers, H. D.

    1976-01-01

    Acoustic design features and techniques employed in the Quiet Clean Short-Haul Experimental Engine (QCSEE) Program are described. The role of jet/flap noise in selecting the engine fan pressure ratio for powered lift propulsion systems is discussed. The QCSEE acoustic design features include a hybrid inlet (near-sonic throat velocity with acoustic treatment); low fan and core pressure ratios; low fan tip speeds; gear-driven fans; high and low frequency stacked core noise treatment; multiple-thickness treatment; bulk absorber treatment; and treatment on the stator vanes. The QCSEE designs represent and anticipated acoustic technology improvement of 12 to 16 PNdb relative to the noise levels of the low-noise engines used on current wide-body commercial jet transport aircraft.

  10. Acoustic non-diffracting Airy beam

    SciTech Connect

    Lin, Zhou; Guo, Xiasheng Tu, Juan; Ma, Qingyu; Wu, Junru; Zhang, Dong

    2015-03-14

    The acoustic non-diffracting Airy beam as its optical counterpart has unique features of self-bending and self-healing. The complexity of most current designs handicaps its applications. A simple design of an acoustic source capable of generating multi-frequency and broad-band acoustic Airy beam has been theoretically demonstrated by numerical simulations. In the design, a piston transducer is corrugated to induce spatial phase variation for transducing the Airy function. The piston's surface is grooved in a pattern that the width of each groove corresponds to the half wavelength of Airy function. The resulted frequency characteristics and its dependence on the size of the piston source are also discussed. This simple design may promote the wide applications of acoustic Airy beam particularly in the field of medical ultrasound.

  11. On observing acoustic backscattering from salinity turbulence.

    PubMed

    Goodman, Louis; Sastre-Cordova, Marcos M

    2011-08-01

    It has been hypothesized that at sufficiently high levels of oceanic salinity turbulence it should be possible to observe acoustic backscattering. However, there have been limited in situ measurements to confirm this hypothesis. Using an autonomous underwater vehicle equipped with upward and downward looking 1.2 MHz acoustic Doppler current profilers and with turbulence and fine scale sensors, measurements were performed in a region of intense turbulence and a strong salinity gradient. The approach taken was to correlate variations in the backscattered acoustic intensity, I, with a theoretical acoustic backscattering cross section per volume for salinity turbulence, σ(s), to obtain an estimated scattering cross section per volume, σ(e). Results indicated that of order 50% of the observed region was characterized by salinity turbulence induced backscattering. PMID:21877785

  12. DETECTING BARYON ACOUSTIC OSCILLATIONS

    SciTech Connect

    Labatie, A.; Starck, J. L.

    2012-02-20

    Baryon acoustic oscillations (BAOs) are a feature imprinted in the galaxy distribution by acoustic waves traveling in the plasma of the early universe. Their detection at the expected scale in large-scale structures strongly supports current cosmological models with a nearly linear evolution from redshift z Almost-Equal-To 1000 and the existence of dark energy. In addition, BAOs provide a standard ruler for studying cosmic expansion. In this paper, we focus on methods for BAO detection using the correlation function measurement {xi}-hat. For each method, we want to understand the tested hypothesis (the hypothesis H{sub 0} to be rejected) and the underlying assumptions. We first present wavelet methods which are mildly model-dependent and mostly sensitive to the BAO feature. Then we turn to fully model-dependent methods. We present the method used most often based on the {chi}{sup 2} statistic, but we find that it has limitations. In general the assumptions of the {chi}{sup 2} method are not verified, and it only gives a rough estimate of the significance. The estimate can become very wrong when considering more realistic hypotheses, where the covariance matrix of {xi}-hat depends on cosmological parameters. Instead, we propose to use the {Delta}l method based on two modifications: we modify the procedure for computing the significance and make it rigorous, and we modify the statistic to obtain better results in the case of varying covariance matrix. We verify with simulations that correct significances are different from the ones obtained using the classical {chi}{sup 2} procedure. We also test a simple example of varying covariance matrix. In this case we find that our modified statistic outperforms the classical {chi}{sup 2} statistic when both significances are correctly computed. Finally, we find that taking into account variations of the covariance matrix can change both BAO detection levels and cosmological parameter constraints.

  13. Localized acoustic surface modes

    NASA Astrophysics Data System (ADS)

    Farhat, Mohamed; Chen, Pai-Yen; Bağcı, Hakan

    2016-04-01

    We introduce the concept of localized acoustic surface modes. We demonstrate that they are induced on a two-dimensional cylindrical rigid surface with subwavelength corrugations under excitation by an incident acoustic plane wave. Our results show that the corrugated rigid surface is acoustically equivalent to a cylindrical scatterer with uniform mass density that can be represented using a Drude-like model. This, indeed, suggests that plasmonic-like acoustic materials can be engineered with potential applications in various areas including sensing, imaging, and cloaking.

  14. Low frequency acoustic microscope

    DOEpatents

    Khuri-Yakub, Butrus T.

    1986-11-04

    A scanning acoustic microscope is disclosed for the detection and location of near surface flaws, inclusions or voids in a solid sample material. A focused beam of acoustic energy is directed at the sample with its focal plane at the subsurface flaw, inclusion or void location. The sample is scanned with the beam. Detected acoustic energy specularly reflected and mode converted at the surface of the sample and acoustic energy reflected by subsurface flaws, inclusions or voids at the focal plane are used for generating an interference signal which is processed and forms a signal indicative of the subsurface flaws, inclusions or voids.

  15. Acoustic dispersive prism.

    PubMed

    Esfahlani, Hussein; Karkar, Sami; Lissek, Herve; Mosig, Juan R

    2016-01-01

    The optical dispersive prism is a well-studied element, which allows separating white light into its constituent spectral colors, and stands in nature as water droplets. In analogy to this definition, the acoustic dispersive prism should be an acoustic device with capability of splitting a broadband acoustic wave into its constituent Fourier components. However, due to the acoustical nature of materials as well as the design and fabrication difficulties, there is neither any natural acoustic counterpart of the optical prism, nor any artificial design reported so far exhibiting an equivalent acoustic behaviour. Here, based on exotic properties of the acoustic transmission-line metamaterials and exploiting unique physical behaviour of acoustic leaky-wave radiation, we report the first acoustic dispersive prism, effective within the audible frequency range 800 Hz-1300 Hz. The dispersive nature, and consequently the frequency-dependent refractive index of the metamaterial are exploited to split the sound waves towards different and frequency-dependent directions. Meanwhile, the leaky-wave nature of the structure facilitates the sound wave radiation into the ambient medium. PMID:26739504

  16. Acoustic dispersive prism

    PubMed Central

    Esfahlani, Hussein; Karkar, Sami; Lissek, Herve; Mosig, Juan R.

    2016-01-01

    The optical dispersive prism is a well-studied element, which allows separating white light into its constituent spectral colors, and stands in nature as water droplets. In analogy to this definition, the acoustic dispersive prism should be an acoustic device with capability of splitting a broadband acoustic wave into its constituent Fourier components. However, due to the acoustical nature of materials as well as the design and fabrication difficulties, there is neither any natural acoustic counterpart of the optical prism, nor any artificial design reported so far exhibiting an equivalent acoustic behaviour. Here, based on exotic properties of the acoustic transmission-line metamaterials and exploiting unique physical behaviour of acoustic leaky-wave radiation, we report the first acoustic dispersive prism, effective within the audible frequency range 800 Hz–1300 Hz. The dispersive nature, and consequently the frequency-dependent refractive index of the metamaterial are exploited to split the sound waves towards different and frequency-dependent directions. Meanwhile, the leaky-wave nature of the structure facilitates the sound wave radiation into the ambient medium. PMID:26739504

  17. Acoustic dispersive prism

    NASA Astrophysics Data System (ADS)

    Esfahlani, Hussein; Karkar, Sami; Lissek, Herve; Mosig, Juan R.

    2016-01-01

    The optical dispersive prism is a well-studied element, which allows separating white light into its constituent spectral colors, and stands in nature as water droplets. In analogy to this definition, the acoustic dispersive prism should be an acoustic device with capability of splitting a broadband acoustic wave into its constituent Fourier components. However, due to the acoustical nature of materials as well as the design and fabrication difficulties, there is neither any natural acoustic counterpart of the optical prism, nor any artificial design reported so far exhibiting an equivalent acoustic behaviour. Here, based on exotic properties of the acoustic transmission-line metamaterials and exploiting unique physical behaviour of acoustic leaky-wave radiation, we report the first acoustic dispersive prism, effective within the audible frequency range 800 Hz-1300 Hz. The dispersive nature, and consequently the frequency-dependent refractive index of the metamaterial are exploited to split the sound waves towards different and frequency-dependent directions. Meanwhile, the leaky-wave nature of the structure facilitates the sound wave radiation into the ambient medium.

  18. Audioptimization: Goal-based acoustic design

    NASA Astrophysics Data System (ADS)

    Monks, Michael Christopher

    Acoustic design is a difficult process, 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 of computer simulation and visualization techniques for acoustic design and analysis has yielded a variety of approaches for modeling acoustic performance. However, current computer-aided design and simulation tools suffer from two major drawbacks. First, obtaining the desired acoustic effects may require a long, tedious sequence of modeling and/or simulation steps. Second, current techniques for modeling the propagation of sound in an environment are prohibitively slow and do not support interactive design. This thesis presents a new approach to computer-aided acoustic design. It is based on the inverse problem of determining material and geometric settings for an environment from a description of the desired performance. The user interactively indicates a range of acceptable material and geometric modifications for an auditorium or similar space, and specifies acoustic goals in space and time by choosing target values for a set of acoustic measures. Given this set of goals and constraints, the system performs an optimization of surface material and geometric parameters using a combination of simulated annealing and steepest descent techniques. Visualization tools extract and present the simulated sound field for points sampled in space and time. The user manipulates the visualizations to create an intuitive expression of acoustic design goals. Interactive rates are achieved for surface material modifications by preprocessing the geometric component of the simulation, and accelerate geometric modifications to the auditorium. by trading accuracy for speed through a number of interactive controls. I describe an interactive system that allows flexible input and display of the solution and report results for several performance spaces. (Copies

  19. The accuracy of portable peak flow meters.

    PubMed Central

    Miller, M R; Dickinson, S A; Hitchings, D J

    1992-01-01

    BACKGROUND: The variability of peak expiratory flow (PEF) is now commonly used in the diagnosis and management of asthma. It is essential for PEF meters to have a linear response in order to obtain an unbiased measurement of PEF variability. As the accuracy and linearity of portable PEF meters have not been rigorously tested in recent years this aspect of their performance has been investigated. METHODS: The response of several portable PEF meters was tested with absolute standards of flow generated by a computer driven, servo controlled pump and their response was compared with that of a pneumotachograph. RESULTS: For each device tested the readings were highly repeatable to within the limits of accuracy with which the pointer position can be assessed by eye. The between instrument variation in reading for six identical devices expressed as a 95% confidence limit was, on average across the range of flows, +/- 8.5 l/min for the Mini-Wright, +/- 7.9 l/min for the Vitalograph, and +/- 6.4 l/min for the Ferraris. PEF meters based on the Wright meter all had similar error profiles with overreading of up to 80 l/min in the mid flow range from 300 to 500 l/min. This overreading was greatest for the Mini-Wright and Ferraris devices, and less so for the original Wright and Vitalograph meters. A Micro-Medical Turbine meter was accurate up to 400 l/min and then began to underread by up to 60 l/min at 720 l/min. For the low range devices the Vitalograph device was accurate to within 10 l/min up to 200 l/min, with the Mini-Wright overreading by up to 30 l/min above 150 l/min. CONCLUSION: Although the Mini-Wright, Ferraris, and Vitalograph meters gave remarkably repeatable results their error profiles for the full range meters will lead to important errors in recording PEF variability. This may lead to incorrect diagnosis and bias in implementing strategies of asthma treatment based on PEF measurement. PMID:1465746

  20. 20 Meter Solar Sail Analysis and Correlation

    NASA Technical Reports Server (NTRS)

    Taleghani, B. K.; Lively, P. S.; Banik, J.; Murphy, D. M.; Trautt, T. A.

    2005-01-01

    This paper describes finite element analyses and correlation studies to predict deformations and vibration modes/frequencies of a 20-meter solar sail system developed by ATK Space Systems. Under the programmatic leadership of NASA Marshall Space Flight Center's In-Space Propulsion activity, the 20-meter solar sail program objectives were to verify the design, to assess structural responses of the sail system, to implement lessons learned from a previous 10-meter quadrant system analysis and test program, and to mature solar sail technology to a technology readiness level (TRL) of 5. For this 20 meter sail system, static and ground vibration tests were conducted in NASA Glenn Research Center's 100 meter diameter vacuum chamber at Plum Brook station. Prior to testing, a preliminary analysis was performed to evaluate test conditions and to determine sensor and actuator locations. After testing was completed, an analysis of each test configuration was performed. Post-test model refinements included updated properties to account for the mass of sensors, wiring, and other components used for testing. This paper describes the development of finite element models (FEM) for sail membranes and masts in each of four quadrants at both the component and system levels, as well as an optimization procedure for the static test/analyses correlation.

  1. Use of Coriolis meters in gas applications

    SciTech Connect

    Patten, T.; Pawlas, G.

    1995-12-31

    Coriolis mass flowmeters provide a solution for measuring the mass flow rate of gases directly. Recent calibration data on compressed air shows that the factory water calibration is also valid on air. In addition, a Coriolis meter is fundamentally linear resulting in an accurate measurement over a wide flow range. Data are presented based on testing performed on Micro Motion 25 mm, 50 mm, and 75 mm Coriolis mass flowmeters on compressed air. Test pressures ranging between 1.7 bar (25 psia) and 100 bar (1450 psia) and mass flow rates ranging between 100:1 to 10:1, depending on the meter size. All calibration points fell with {plus_minus}2%, with a significant portion of the data within {plus_minus}5%. Data are also presented for a 6 mm meter on natural gas at 100 bar; all data are within {plus_minus}0.5%. Repeatability data are presented for a 9 mm meter calibrated on 100 bar air for calibration run times between 10 and 60 seconds. Meter repeatability improved approximately 10 times to {plus_minus}0.15% when the calibration time was 60 seconds.

  2. The 4-meter lunar engineering telescope

    NASA Technical Reports Server (NTRS)

    Peacock, Keith; Giannini, Judith A.; Kilgus, Charles C.; Bely, Pierre Y.; May, B. Scott; Cooper, Shannon A.; Schlimm, Gerard H.; Sounder, Charles; Ormond, Karen; Cheek, Eric

    1991-01-01

    The 16-meter diffraction limited lunar telescope incorporates a primary mirror with 312 one-meter segments; 3 nanometer active optics surface control with laser metrology and hexapod positioners; a space frame structure with one-millimeter stability; and a hexapod mount for pointing. The design data needed to limit risk in this development can be obtained by building a smaller engineering telescope on the moon with all of the features of the 16-meter design. This paper presents a 4.33-meter engineering telescope concept developed by the Summer 1990 Student Program of the NASA/JHU Space Grant Consortium Lunar Telescope Project. The primary mirror, made up of 18 one-meter hexagonal segments, is sized to provide interesting science as well as engineering data. The optics are configured as a Ritchey-Chretien with a coude relay to the focal plane beneath the surface. The optical path is continuously monitored with 3-nanometer precision interferometrically. An active optics processor and piezoelectric actuators operate to maintain the end-to-end optical configuration established by wave front sensing using a guide star. The mirror segments, consisting of a one-centimeter thick faceplate on 30-cm deep ribs, maintain the surface figure to a few nanometers under lunar gravity and thermal environment.

  3. Fish effects on ocean current observations in the Cariaco Basin

    NASA Astrophysics Data System (ADS)

    Virmani, Jyotika I.; Weisberg, Robert H.

    2009-03-01

    Multiple years of moored current meter observations from the Cariaco Basin show low-frequency variations along with near-inertial waves and further imply the persistent diurnal movement of fish species known to populate the basin. In agreement with short-term observations from 1979, the more recent observations with acoustic Doppler current profilers provide evidence of the multidecadal presence and behavior of these species. An unwanted corollary, however, is a bias in both the vertical and horizontal components of velocity due to the fish movements. Removal of this fish bias results in large data loss (approximately 72%); however, an interpolated, non-biased data set is developed with depth-averaged horizontal velocities comparable to the observations, demonstrating successful elimination of the bias. Further comparisons show that the interpolated data result in minimal variance density loss at low frequencies and a reduction of variance density at high frequencies such that the interpolated data in the internal wave range more closely fit the Garrett-Munk spectrum. The net result is a data set appropriate for further analysis. A mean downward velocity of 0.18 cm s-1 is a reflection of a biogenic particle flux and some residual fish contamination. The mean settling speed of particles in the Cariaco Basin is calculated, via Stokes law, to be smaller than 0.04 cm s-1. Velocity observations from acoustic current meters at depths greater than 400 m are impacted by the water clarity; therefore alternate methods should be used to make velocity measurements at depth.

  4. Place Postage on Metered Reply Mail Using Postage Meter. Student's Manual and Instructor's Manual.

    ERIC Educational Resources Information Center

    Bostian, Nancy

    Supporting performance objective 64 of the V-TECS (Vocational-Technical Education Consortium of States) Secretarial Catalog, both a set of student materials and an instructor's manual on placing postage on metered reply mail using a postage meter are included in this packet. (The packet is the sixth in a set of eight on performing mail…

  5. An evaporation based digital microflow meter

    NASA Astrophysics Data System (ADS)

    Nie, C.; Frijns, A. J. H.; Mandamparambil, R.; Zevenbergen, M. A. G.; den Toonder, J. M. J.

    2015-11-01

    In this work, we present a digital microflow meter operating in the range 30-250 nl min-1 for water. The principle is based on determining the evaporation rate of the liquid via reading the number of wetted pore array structures in a microfluidic system, through which continuous evaporation takes place. A proof-of-principle device of the digital flow meter was designed, fabricated, and tested. The device was built on foil-based technology. In the proof-of-principle experiments, good agreement was found between set flow rates and the evaporation rates estimated from reading the number of wetted pore structures. The measurement range of the digital flow meter can be tuned and extended in a straightforward manner by changing the pore structure of the device.

  6. The challenge of acoustics

    NASA Astrophysics Data System (ADS)

    Lord, P.

    1981-01-01

    The various applications of acoustics, including sonar, ultrasonic examination of unborn foetuses and architectural applications, are briefly reviewed. Problems in traffic and industrial noise, auditorium design and explosive noise are considered in more detail. The educational aspects of acoustical science and technology are briefly considered.

  7. 8-Meter UV/Optical Space Telescope

    NASA Technical Reports Server (NTRS)

    Stahl, H. Philip

    2008-01-01

    This slide presentation proposes using the unprecedented capability of the planned Ares V launch vehicle, to place a 8 meter monolithic space telescope at the Earth-Sun L2 point. This new capability enables a new design pardigm -- simplicity. The six to eight meter class telescope with a massive high Technical Readiness Level ground observatory class monolithic primary mirror has been determined feasible. The proposed design, structural analysis, spacecraft design and shroud integration, thermal analysis, propulsion system, guidance navigation and pointing control assumptions about the avionics, and power systems, operational lifetime, and the idea of in-space servicing are reviewed.

  8. Quantum noise of non-ideal Sagnac speed meter interferometer with asymmetries

    NASA Astrophysics Data System (ADS)

    Danilishin, S. L.; Gräf, C.; Leavey, S. S.; Hennig, J.; Houston, E. A.; Pascucci, D.; Steinlechner, S.; Wright, J.; Hild, S.

    2015-04-01

    The speed meter concept has been identified as a technique that can potentially provide laser-interferometric measurements at a sensitivity level which surpasses the standard quantum limit (SQL) over a broad frequency range. As with other sub-SQL measurement techniques, losses play a central role in speed meter interferometers and they ultimately determine the quantum noise limited sensitivity that can be achieved. So far in the literature, the quantum noise limited sensitivity has only been derived for lossless or lossy cases using certain approximations (for instance that the arm cavity round trip loss is small compared to the arm cavity mirror transmission). In this article we present a generalized, analytical treatment of losses in speed meters that allows accurate calculation of the quantum noise limited sensitivity of Sagnac speed meters with arm cavities. In addition, our analysis allows us to take into account potential imperfections in the interferometer such as an asymmetric beam splitter or differences of the reflectivities of the two arm cavity input mirrors. Finally, we use the examples of the proof-of-concept Sagnac speed meter currently under construction in Glasgow and a potential implementation of a Sagnac speed meter in the Einstein Telescope to illustrate how our findings affect Sagnac speed meters with metre- and kilometre-long baselines.

  9. Highly directional acoustic receivers.

    PubMed

    Cray, Benjamin A; Evora, Victor M; Nuttall, Albert H

    2003-03-01

    The theoretical directivity of a single combined acoustic receiver, a device that can measure many quantities of an acoustic field at a collocated point, is presented here. The formulation is developed using a Taylor series expansion of acoustic pressure about the origin of a Cartesian coordinate system. For example, the quantities measured by a second-order combined receiver, denoted a dyadic sensor, are acoustic pressure, the three orthogonal components of acoustic particle velocity, and the nine spatial gradients of the velocity vector. The power series expansion, which can be of any order, is cast into an expression that defines the directivity of a single receiving element. It is shown that a single highly directional dyadic sensor can have a directivity index of up to 9.5 dB. However, there is a price to pay with highly directive sensors; these sensors can be significantly more sensitive to nonacoustic noise sources. PMID:12656387

  10. Acoustic Remote Sensing

    NASA Astrophysics Data System (ADS)

    Dowling, David R.; Sabra, Karim G.

    2015-01-01

    Acoustic waves carry information about their source and collect information about their environment as they propagate. This article reviews how these information-carrying and -collecting features of acoustic waves that travel through fluids can be exploited for remote sensing. In nearly all cases, modern acoustic remote sensing involves array-recorded sounds and array signal processing to recover multidimensional results. The application realm for acoustic remote sensing spans an impressive range of signal frequencies (10-2 to 107 Hz) and distances (10-2 to 107 m) and involves biomedical ultrasound imaging, nondestructive evaluation, oil and gas exploration, military systems, and Nuclear Test Ban Treaty monitoring. In the past two decades, approaches have been developed to robustly localize remote sources; remove noise and multipath distortion from recorded signals; and determine the acoustic characteristics of the environment through which the sound waves have traveled, even when the recorded sounds originate from uncooperative sources or are merely ambient noise.

  11. Acoustic integrated extinction

    PubMed Central

    Norris, Andrew N.

    2015-01-01

    The integrated extinction (IE) is defined as the integral of the scattering cross section as a function of wavelength. Sohl et al. (2007 J. Acoust. Soc. Am. 122, 3206–3210. (doi:10.1121/1.2801546)) derived an IE expression for acoustic scattering that is causal, i.e. the scattered wavefront in the forward direction arrives later than the incident plane wave in the background medium. The IE formula was based on electromagnetic results, for which scattering is causal by default. Here, we derive a formula for the acoustic IE that is valid for causal and non-causal scattering. The general result is expressed as an integral of the time-dependent forward scattering function. The IE reduces to a finite integral for scatterers with zero long-wavelength monopole and dipole amplitudes. Implications for acoustic cloaking are discussed and a new metric is proposed for broadband acoustic transparency. PMID:27547100

  12. Virtual acoustics displays

    NASA Technical Reports Server (NTRS)

    Wenzel, Elizabeth M.; Fisher, Scott S.; Stone, Philip K.; Foster, Scott H.

    1991-01-01

    The real time acoustic display capabilities are described which were developed for the Virtual Environment Workstation (VIEW) Project at NASA-Ames. The acoustic display is capable of generating localized acoustic cues in real time over headphones. An auditory symbology, a related collection of representational auditory 'objects' or 'icons', can be designed using ACE (Auditory Cue Editor), which links both discrete and continuously varying acoustic parameters with information or events in the display. During a given display scenario, the symbology can be dynamically coordinated in real time with 3-D visual objects, speech, and gestural displays. The types of displays feasible with the system range from simple warnings and alarms to the acoustic representation of multidimensional data or events.

  13. Cochlear bionic acoustic metamaterials

    NASA Astrophysics Data System (ADS)

    Ma, Fuyin; Wu, Jiu Hui; Huang, Meng; Fu, Gang; Bai, Changan

    2014-11-01

    A design of bionic acoustic metamaterial and acoustic functional devices was proposed by employing the mammalian cochlear as a prototype. First, combined with the experimental data in previous literatures, it is pointed out that the cochlear hair cells and stereocilia cluster are a kind of natural biological acoustic metamaterials with the negative stiffness characteristics. Then, to design the acoustic functional devices conveniently in engineering application, a simplified parametric helical structure was proposed to replace actual irregular cochlea for bionic design, and based on the computational results of such a bionic parametric helical structure, it is suggested that the overall cochlear is a local resonant system with the negative dynamic effective mass characteristics. There are many potential applications in the bandboard energy recovery device, cochlear implant, and acoustic black hole.

  14. Acoustic emission beamforming for enhanced damage detection

    NASA Astrophysics Data System (ADS)

    McLaskey, Gregory C.; Glaser, Steven D.; Grosse, Christian U.

    2008-03-01

    As civil infrastructure ages, the early detection of damage in a structure becomes increasingly important for both life safety and economic reasons. This paper describes the analysis procedures used for beamforming acoustic emission techniques as well as the promising results of preliminary experimental tests on a concrete bridge deck. The method of acoustic emission offers a tool for detecting damage, such as cracking, as it occurs on or in a structure. In order to gain meaningful information from acoustic emission analyses, the damage must be localized. Current acoustic emission systems with localization capabilities are very costly and difficult to install. Sensors must be placed throughout the structure to ensure that the damage is encompassed by the array. Beamforming offers a promising solution to these problems and permits the use of wireless sensor networks for acoustic emission analyses. Using the beamforming technique, the azmuthal direction of the location of the damage may be estimated by the stress waves impinging upon a small diameter array (e.g. 30mm) of acoustic emission sensors. Additional signal discrimination may be gained via array processing techniques such as the VESPA process. The beamforming approach requires no arrival time information and is based on very simple delay and sum beamforming algorithms which can be easily implemented on a wireless sensor or mote.

  15. 49 CFR 192.359 - Customer meter installations: Operating pressure.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Customer meter installations: Operating pressure... Meters, Service Regulators, and Service Lines § 192.359 Customer meter installations: Operating pressure. (a) A meter may not be used at a pressure that is more than 67 percent of the manufacturer's...

  16. 39 CFR 501.15 - Computerized Meter Resetting System.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 39 Postal Service 1 2012-07-01 2012-07-01 false Computerized Meter Resetting System. 501.15... AND DISTRIBUTE POSTAGE EVIDENCING SYSTEMS § 501.15 Computerized Meter Resetting System. (a) Description. The Computerized Meter Resetting System (CMRS) permits customers to reset their postage meters...

  17. 18 CFR 367.9020 - Account 902, Meter reading expenses.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 18 Conservation of Power and Water Resources 1 2013-04-01 2013-04-01 false Account 902, Meter... GAS ACT Operation and Maintenance Expense Chart of Accounts § 367.9020 Account 902, Meter reading... customer meters, and determining consumption when performed by employees engaged in reading meters....

  18. 49 CFR 192.353 - Customer meters and regulators: Location.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Customer meters and regulators: Location. 192.353... TRANSPORTATION OF NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Customer Meters, Service Regulators, and Service Lines § 192.353 Customer meters and regulators: Location. (a) Each meter and...

  19. 49 CFR 192.359 - Customer meter installations: Operating pressure.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Customer meter installations: Operating pressure... Meters, Service Regulators, and Service Lines § 192.359 Customer meter installations: Operating pressure. (a) A meter may not be used at a pressure that is more than 67 percent of the manufacturer's...

  20. 18 CFR 367.9020 - Account 902, Meter reading expenses.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 18 Conservation of Power and Water Resources 1 2014-04-01 2014-04-01 false Account 902, Meter... GAS ACT Operation and Maintenance Expense Chart of Accounts § 367.9020 Account 902, Meter reading... customer meters, and determining consumption when performed by employees engaged in reading meters....

  1. 49 CFR 192.353 - Customer meters and regulators: Location.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Customer meters and regulators: Location. 192.353... TRANSPORTATION OF NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Customer Meters, Service Regulators, and Service Lines § 192.353 Customer meters and regulators: Location. (a) Each meter and...

  2. 49 CFR 192.357 - Customer meters and regulators: Installation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Customer meters and regulators: Installation. 192... Meters, Service Regulators, and Service Lines § 192.357 Customer meters and regulators: Installation. (a) Each meter and each regulator must be installed so as to minimize anticipated stresses upon...

  3. 49 CFR 192.359 - Customer meter installations: Operating pressure.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Customer meter installations: Operating pressure... Meters, Service Regulators, and Service Lines § 192.359 Customer meter installations: Operating pressure. (a) A meter may not be used at a pressure that is more than 67 percent of the manufacturer's...

  4. 49 CFR 192.353 - Customer meters and regulators: Location.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Customer meters and regulators: Location. 192.353... TRANSPORTATION OF NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Customer Meters, Service Regulators, and Service Lines § 192.353 Customer meters and regulators: Location. (a) Each meter and...

  5. 39 CFR 501.15 - Computerized Meter Resetting System.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 39 Postal Service 1 2014-07-01 2014-07-01 false Computerized Meter Resetting System. 501.15... AND DISTRIBUTE POSTAGE EVIDENCING SYSTEMS § 501.15 Computerized Meter Resetting System. (a) Description. The Computerized Meter Resetting System (CMRS) permits customers to reset their postage meters...

  6. 49 CFR 192.357 - Customer meters and regulators: Installation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Customer meters and regulators: Installation. 192... Meters, Service Regulators, and Service Lines § 192.357 Customer meters and regulators: Installation. (a) Each meter and each regulator must be installed so as to minimize anticipated stresses upon...

  7. 49 CFR 192.357 - Customer meters and regulators: Installation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Customer meters and regulators: Installation. 192... Meters, Service Regulators, and Service Lines § 192.357 Customer meters and regulators: Installation. (a) Each meter and each regulator must be installed so as to minimize anticipated stresses upon...

  8. 39 CFR 501.15 - Computerized Meter Resetting System.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 39 Postal Service 1 2011-07-01 2011-07-01 false Computerized Meter Resetting System. 501.15... AND DISTRIBUTE POSTAGE EVIDENCING SYSTEMS § 501.15 Computerized Meter Resetting System. (a) Description. The Computerized Meter Resetting System (CMRS) permits customers to reset their postage meters...

  9. 18 CFR 367.9020 - Account 902, Meter reading expenses.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 18 Conservation of Power and Water Resources 1 2011-04-01 2011-04-01 false Account 902, Meter... GAS ACT Operation and Maintenance Expense Chart of Accounts § 367.9020 Account 902, Meter reading... customer meters, and determining consumption when performed by employees engaged in reading meters....

  10. 49 CFR 192.357 - Customer meters and regulators: Installation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Customer meters and regulators: Installation. 192... Meters, Service Regulators, and Service Lines § 192.357 Customer meters and regulators: Installation. (a) Each meter and each regulator must be installed so as to minimize anticipated stresses upon...

  11. 49 CFR 192.353 - Customer meters and regulators: Location.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Customer meters and regulators: Location. 192.353... TRANSPORTATION OF NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Customer Meters, Service Regulators, and Service Lines § 192.353 Customer meters and regulators: Location. (a) Each meter and...

  12. 49 CFR 192.359 - Customer meter installations: Operating pressure.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Customer meter installations: Operating pressure... Meters, Service Regulators, and Service Lines § 192.359 Customer meter installations: Operating pressure. (a) A meter may not be used at a pressure that is more than 67 percent of the manufacturer's...

  13. 39 CFR 501.15 - Computerized Meter Resetting System.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 39 Postal Service 1 2013-07-01 2013-07-01 false Computerized Meter Resetting System. 501.15... AND DISTRIBUTE POSTAGE EVIDENCING SYSTEMS § 501.15 Computerized Meter Resetting System. (a) Description. The Computerized Meter Resetting System (CMRS) permits customers to reset their postage meters...

  14. 18 CFR 367.9020 - Account 902, Meter reading expenses.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 18 Conservation of Power and Water Resources 1 2012-04-01 2012-04-01 false Account 902, Meter... GAS ACT Operation and Maintenance Expense Chart of Accounts § 367.9020 Account 902, Meter reading... customer meters, and determining consumption when performed by employees engaged in reading meters....

  15. 49 CFR 192.353 - Customer meters and regulators: Location.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Customer meters and regulators: Location. 192.353... TRANSPORTATION OF NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Customer Meters, Service Regulators, and Service Lines § 192.353 Customer meters and regulators: Location. (a) Each meter and...

  16. WENDI: an improved neutron rem meter.

    PubMed

    Olsher, R H; Hsu, H H; Beverding, A; Kleck, J H; Casson, W H; Vasilik, D G; Devine, R T

    2000-08-01

    Neutron rem meters are routinely used for real-time field measurements of neutron dose equivalent where neutron spectra are unknown or poorly characterized. These meters are designed so that their response per unit fluence approximates an appropriate fluence-to-dose conversion function. Typically, a polyethylene moderator assembly surrounds a thermal neutron detector, such as a BF3 counter tube. Internal absorbers may also be used to further fine-tune the detector response to the shape of the desired fluence conversion function. Historical designs suffer from a number of limitations. Accuracy for some designs is poor at intermediate energies (50 keV-250 keV) critical for nuclear power plant dosimetry. The well-known Andersson-Braun design suffers from angular dependence because of its lack of spherical symmetry. Furthermore, all models using a pure polyethylene moderator have no useful high-energy response, which makes them inaccurate around high-energy accelerator facilities. This paper describes two new neutron rem meter designs with improved accuracy over the energy range from thermal to 5 GeV. The Wide Energy Neutron Detection Instrument (WENDI) makes use of both neutron generation and absorption to contour the detector response function. Tungsten or tungsten carbide (WC) powder is added to a polyethylene moderator with the expressed purpose of generating spallation neutrons in tungsten nuclei and thus enhance the high-energy response of the meter beyond 8 MeV. Tungsten's absorption resonance structure below several keV was also found to be useful in contouring the meter's response function. The WENDI rem meters were designed and optimized using the Los Alamos Monte Carlo codes MCNP, MCNPX, and LAHET. A first generation prototype (WENDI-I) was built in 1995 and its testing was completed in 1996. This design placed a BF3 counter in the center of a spherical moderator assembly, whose outer shell consisted of 30% by weight WC in a matrix of polyethylene. A borated

  17. Moisture transport into chlorofluorocarbon-free metered dose inhalers.

    PubMed

    Williams, G

    1999-12-01

    Moisture is known to affect the stability of some metered dose inhalers (MDIs). Hydrofluoroalkanes such as tetrafluoroethane (134a) and heptafluoropropane (227) are known to have higher affinity for moisture than the currently used chlorofluorocarbon propellents. An initial study was conducted to determine the water vapor transmission rates of various elastomers that may be used as gaskets in MDIs. A further study was conducted to measure the moisture ingress rates of various chlorofluorocarbon-free MDIs. The data indicate that moisture transport into chlorofluorocarbon-free MDIs is influenced by the elastomeric nature of the gaskets used and the type of hydrofluoroalkane formulation and storage conditions used. PMID:10588979

  18. The Five-hundred-meter Aperture Spherical Radio Telescope Project

    NASA Astrophysics Data System (ADS)

    Li, Di; Pan, Zhichen

    2016-07-01

    The Five-hundred-meter Aperture Spherical Radio Telescope (FAST) is a Chinese megascience project funded by the National Development and Reform Commission (NDRC) of the People's Republic of China. The National Astronomical Observatories of China (NAOC) is in charge of its construction and subsequent operation. Upon its expected completion in September 2016, FAST will surpass the 305 m Arecibo Telescope and the 100 m Green Bank Telescope in terms of absolute sensitivity in the 70 MHz to 3 GHz bands. In this paper, we report on the project, its current status, the key science goals, and plans for early science.

  19. Systems and methods of monitoring acoustic pressure to detect a flame condition in a gas turbine

    SciTech Connect

    Ziminsky, Willy Steve; Krull, Anthony Wayne; Healy, Timothy Andrew , Yilmaz, Ertan

    2011-05-17

    A method may detect a flashback condition in a fuel nozzle of a combustor. The method may include obtaining a current acoustic pressure signal from the combustor, analyzing the current acoustic pressure signal to determine current operating frequency information for the combustor, and indicating that the flashback condition exists based at least in part on the current operating frequency information.

  20. Real life experience with multipath ultrasonic gas flow meters

    SciTech Connect

    Sakariassen, R.

    1996-12-31

    Multipath ultrasonic gas flow meters are to be considered as newcomers among flow meters for large, high pressure gas flows. Although the advantages of this type of meters are many and obvious, the metering community is still hesitating to go for it mainly because of lack of experience. The objective of this paper is to present the experience of Statoil after more than six years experience with multipath ultrasonic gas flow meters. Their experience includes laboratory testing and operation in the field for a variety of designs and dimensions. This paper presents the accuracy achieved by such meters including comparison between ultrasonic meters and orifice metering systems in operation, the unique possibilities that this type of meter offers for on-line verification of performance and installation effects. Of particular interest should be noted that in the vicinity of low-noise control valves, such meters could stop functioning completely if no precautions are taken.

  1. Topological charge pump by surface acoustic waves

    NASA Astrophysics Data System (ADS)

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

    2016-06-01

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

  2. Ocean seismo-acoustics. Low-frequency underwater acoustics

    SciTech Connect

    Akal, T.; berkson, J.M.

    1986-01-01

    This book presents information on seismo-acoustic propagation in seawater and sea beds that includes theoretical developments, modelling and experiments, and fluctuations. Boundary scatteiring, seismo-acoustic waves and seismo-acoustic noise are discussed. Technology and new approaches in seismo-acoustic measurements are presented.

  3. Preserved Acoustic Hearing in Cochlear Implantation Improves Speech Perception

    PubMed Central

    Sheffield, Sterling W.; Jahn, Kelly; Gifford, René H.

    2015-01-01

    Background With improved surgical techniques and electrode design, an increasing number of cochlear implant (CI) recipients have preserved acoustic hearing in the implanted ear, thereby resulting in bilateral acoustic hearing. There are currently no guidelines, however, for clinicians with respect to audio-metric criteria and the recommendation of amplification in the implanted ear. The acoustic bandwidth necessary to obtain speech perception benefit from acoustic hearing in the implanted ear is unknown. Additionally, it is important to determine if, and in which listening environments, acoustic hearing in both ears provides more benefit than hearing in just one ear, even with limited residual hearing. Purpose The purposes of this study were to (1) determine whether acoustic hearing in an ear with a CI provides as much speech perception benefit as an equivalent bandwidth of acoustic hearing in the non-implanted ear, and (2) determine whether acoustic hearing in both ears provides more benefit than hearing in just one ear. Research Design A repeated-measures, within-participant design was used to compare performance across listening conditions. Study Sample Seven adults with CIs and bilateral residual acoustic hearing (hearing preservation) were recruited for the study. Data Collection and Analysis Consonant-nucleus-consonant word recognition was tested in four conditions: CI alone, CI + acoustic hearing in the nonimplanted ear, CI + acoustic hearing in the implanted ear, and CI + bilateral acoustic hearing. A series of low-pass filters were used to examine the effects of acoustic bandwidth through an insert earphone with amplification. Benefit was defined as the difference among conditions. The benefit of bilateral acoustic hearing was tested in both diffuse and single-source background noise. Results were analyzed using repeated-measures analysis of variance. Results Similar benefit was obtained for equivalent acoustic frequency bandwidth in either ear. Acoustic

  4. Developmental Differences in the Effects of Acoustic Similarity on Memory Span.

    ERIC Educational Resources Information Center

    Hulme, Charles

    1984-01-01

    Investigates the effects of acoustic similarity on memory span in 112 children four to 10 years of age. Acoustic similarity had progressively more effect on recall with increasing age. Implications for current theories of short-term memory and its development and for the use of acoustic similarity as an indicator of speech coding are discussed.…

  5. Educational Electrical Appliance Power Meter and Logger

    ERIC Educational Resources Information Center

    Nunn, John

    2013-01-01

    The principles behind two different designs of inductive power meter are presented. They both make use of the microphone input of a computer which, together with a custom-written program, can record the instantaneous power of a domestic electrical appliance. The device can be built quickly and can be calibrated with reference to a known power…

  6. Combustion products generating and metering device

    NASA Technical Reports Server (NTRS)

    Wiberg, R. E.; Klisch, J. A.

    1974-01-01

    Device simulates incipient fire conditions in closely-controlled adjustable manner, to give predetermined degree of intensity at selected locations throughout area, and to verify that detection system will respond. Device can be used with and for cross calibration and experimentation in conjunction with commercially available products of combustion analyzing meters.

  7. Performance of planter meters for cotton

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Components and technology offerings to improve planter performance continue to increase. In particular, new row-meter parts allow units to improve what is called singulation (e.g. reducing skips and doubles) assuming the vacuum pressure is properly set. To help understand the value of all this new t...

  8. Measurement error analysis of taxi meter

    NASA Astrophysics Data System (ADS)

    He, Hong; Li, Dan; Li, Hang; Zhang, Da-Jian; Hou, Ming-Feng; Zhang, Shi-pu

    2011-12-01

    The error test of the taximeter is divided into two aspects: (1) the test about time error of the taximeter (2) distance test about the usage error of the machine. The paper first gives the working principle of the meter and the principle of error verification device. Based on JJG517 - 2009 "Taximeter Verification Regulation ", the paper focuses on analyzing the machine error and test error of taxi meter. And the detect methods of time error and distance error are discussed as well. In the same conditions, standard uncertainty components (Class A) are evaluated, while in different conditions, standard uncertainty components (Class B) are also evaluated and measured repeatedly. By the comparison and analysis of the results, the meter accords with JJG517-2009, "Taximeter Verification Regulation ", thereby it improves the accuracy and efficiency largely. In actual situation, the meter not only makes up the lack of accuracy, but also makes sure the deal between drivers and passengers fair. Absolutely it enriches the value of the taxi as a way of transportation.

  9. Numerical modeling of fluidic flow meters

    NASA Astrophysics Data System (ADS)

    Choudhury, D.; Patel, B. R.

    1992-05-01

    The transient fluid flow in fluidic flow meters has been modeled using Creare.x's flow modeling computer program FLUENT/BFC that solves the Navier-Stokes equations in general curvilinear coordinates. The numerical predictions of fluid flow in a fluidic flow meter have been compared with the available experimental results for a particular design, termed the PC-4 design. Overall flow structures such as main jet bending, and primary and secondary vortices predicted by FLUENT/BFC are in excellent agreement with flow visualization results. The oscillation frequencies of the PC-4 design have been predicted for a range of flow rates encompassing laminar and turbulent flow and the results are in good agreement with experiments. The details of the flow field predictions reveal that an important factor that determines the onset of oscillations in the fluidic flow meter is the feedback jet momentum relative to the main jet momentum. The insights provided by the analysis of the PC-4 fluidic flow meter design have led to an improved design. The improved design has sustained oscillations at lower flow rates compared with the PC-4 design and has a larger rangeability.

  10. Measuring and metering of unsteady flows

    SciTech Connect

    Padmanabhan, M.; Dodge, F.T.; Heidrick, T.R.

    1986-01-01

    This book presents the papers given at a conference on unsteady flow. Topics considered at the conference included the identification of pulsation induced orifice metering errors including gage line shift, electromagnetic flowmeters, mass flow measurements on the flue of a woodburning stove, fluid excitation forces acting on a tube array, and a numerical analysis of pulsating laminar flow through a pipe orifice.

  11. Modernization of the DFA Moisture Meter

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Dried Fruit Association (DFA) Dried Fruit Moisture Tester has been the standard technique for determining moisture in dried fruit for more than 50 years. This method of testing moisture is recognized world wide and is AOAC approved. The meter applies the results of conductivity measurements and ...

  12. Meter Designs Reduce Operation Costs for Industry

    NASA Technical Reports Server (NTRS)

    2013-01-01

    Marshall Space Flight Center collaborated with Quality Monitoring and Control (QMC) of Humble, Texas, through a Space Act Agreement to design a balanced flow meter for the Space Shuttle Program. QMC founded APlus-QMC LLC to commercialize the technology, which has contributed to 100 new jobs, approximately $250,000 in yearly sales, and saved customers an estimated $10 million.

  13. KVP meter errors induced by plastic wrap

    SciTech Connect

    Jefferies, D.; Morris, J.W.; White, V.P. )

    1991-02-01

    The purpose of this study was to determine whether erroneous kVp meter readings, induced by plastic wrap, affected the actual kVp (output) of a dental X-ray machine. To evaluate the effect of plastic wrap on dental X-ray machine kVp meters, a radiation output device was used to measure output in mR/ma.s. An intraoral dental X-ray unit (S.S. White Model {number sign}90W) was used to make the exposures. First, the kVp meter was not covered with plastic wrap and output readings were recorded at various kVp settings with the milliamperage and time held constant. Secondly, the same kVp settings were selected before the plastic wrap was placed. Milliamperage and time were again held to the same constant. The X-ray console was then covered with plastic wrap prior to measuring the output for each kVp. The wrap possessed a static charge. This charge induced erroneous kVp meter readings. Out-put readings at the various induced kVp settings were then recorded. A kVp of 50 with no wrap present resulted in the same output as a kVp of 50 induced to read 40 or 60 kVp by the presence of wrap. Similar results were obtained at other kVp settings. This indicates that the plastic wrap influences only the kVp meter needle and not the actual kilovoltage of the X-ray machine. Dental X-ray machine operators should select kVp meter readings prior to placing plastic wrap and should not adjust initial settings if the meter is deflected later by the presence of wrap. The use of such a procedure will result in proper exposures, fewer retakes, and less patient radiation. If plastic wrap leads to consistent exposure errors, clinicians may wish to use a 0.5% sodium hypochlorite disinfectant as an alternative to the barrier technique.

  14. Capacitive level meters for cryogenic liquids with continuous read-out

    NASA Astrophysics Data System (ADS)

    Velichkov, I. V.; Drobin, V. M.

    The operation of a variety of liquid level meters is briefly considered. Currently used continuous read-out level meters, whose operation is based on the difference between the dielectric constants of the gas and the liquid measured, are compared. The requirements for cryogenic application of these level meters are discussed. An electronic circuit for capacitance measurements with high stability and resolution better than 20 ppm is described along with construction details of capacitance transducers both for liquid nitrogen and liquid helium. The parameters of two particular level meters are reported as follows. For liquid nitrogen: measuring length 50 cm; overall error < 1% at full scale deviation (FSD); short time instabilities < 0.01% FSD; resolution better than 0.05 mm. For liquid helium: measuring length 60 cm; overall error < 5% FSD; short time instabilities < 0.2% FSD; resolution better than 1 mm.

  15. Acoustic cooling engine

    DOEpatents

    Hofler, Thomas J.; Wheatley, John C.; Swift, Gregory W.; Migliori, Albert

    1988-01-01

    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.

  16. Acoustic Gaits: Gait Analysis With Footstep Sounds.

    PubMed

    Altaf, M Umair Bin; Butko, Taras; Juang, Biing-Hwang Fred

    2015-08-01

    We describe the acoustic gaits-the natural human gait quantitative characteristics derived from the sound of footsteps as the person walks normally. We introduce the acoustic gait profile, which is obtained from temporal signal analysis of sound of footsteps collected by microphones and illustrate some of the spatio-temporal gait parameters that can be extracted from the acoustic gait profile by using three temporal signal analysis methods-the squared energy estimate, Hilbert transform and Teager-Kaiser energy operator. Based on the statistical analysis of the parameter estimates, we show that the spatio-temporal parameters and gait characteristics obtained using the acoustic gait profile can consistently and reliably estimate a subset of clinical and biometric gait parameters currently in use for standardized gait assessments. We conclude that the Teager-Kaiser energy operator provides the most consistent gait parameter estimates showing the least variation across different sessions and zones. Acoustic gaits use an inexpensive set of microphones with a computing device as an accurate and unintrusive gait analysis system. This is in contrast to the expensive and intrusive systems currently used in laboratory gait analysis such as the force plates, pressure mats and wearable sensors, some of which may change the gait parameters that are being measured. PMID:25769144

  17. Virtual reflections in electronic acoustic architecture

    NASA Astrophysics Data System (ADS)

    van Munster, Bjorn

    2005-09-01

    In the era of the ancient Greeks and Byzantines, the first attempts for increasing reverberation time are noted. In the 1950s, the Ambiophonic system accomplished this by means of an electronic device, for the first time. The early systems only increased the reverberation time by delaying the picked-up reverberation. With the introduction of multichannel feedback-based systems, the reverberation level also could be increased. Later, it was understood that it was important to also fill in the missing reflections, address reflection density, frequency dependence, etc. This resulted in the development of the SIAP concept. Current DSP technology led to the development of a processor whereby density, length, level, and the frequency content can be controlled for different areas in the same room or different rooms, leading to the concept of the acoustic server. electronic acoustic architecture has become the current state-of-the-art approach for solving acoustic deficiencies in, among others, rehearsal rooms, theaters, churches, and multipurpose venues. Incorporation of complementary passive acoustic solutions provides an optimum solution for all room problems. This paper discusses the utilization of virtual reflections in the new approach of electronic acoustic architecture for different environments. Measurements performed in the Sejong Performing Arts Centre, Seoul, South Korea, show the power of this approach.

  18. Some Problems of modern acoustics

    NASA Technical Reports Server (NTRS)

    Stan, A.

    1974-01-01

    The multidisciplinary and interdisciplinary character of acoustics is considered and its scientific, technological, economical and social implications, as well as the role of acoustics in creating new machines and equipment and improving the quality of products are outlined. Research beyond audible frequencies, as well as to extremely high acoustic intensities, which requires the development of a nonlinear acoustics is elaborated.

  19. Acoustic field effects on a negative corona discharge

    NASA Astrophysics Data System (ADS)

    Bálek, R.; Červenka, M.; Pekárek, S.

    2014-06-01

    For a negative corona discharge under atmospheric pressure in different regimes, we investigated the effects of an acoustic field both on its electrical parameters and on the change in its visual appearance. We found that the application of an acoustic field on the true corona discharge, for particular currents, decreases the discharge voltage. The application of an acoustic field on the discharge in the filamentary streamer regime substantially extends the range of currents for which the discharge voltage remains more or less constant, i.e. it allows a substantial increase in the power delivered to the discharge. The application of an acoustic field on the discharge causes the discharge to spread within the discharge chamber and consequently, a highly reactive non-equilibrium plasma is created throughout the inter-electrode space. Finally, our experimental apparatus radiates almost no acoustic energy from the discharge chamber.

  20. Acoustic well cleaner

    DOEpatents

    Maki, Jr., Voldi E.; Sharma, Mukul M.

    1997-01-21

    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.

  1. Acoustic rotation control

    NASA Technical Reports Server (NTRS)

    Elleman, D. D.; Croonquist, A. P.; Wang, T. G. (Inventor)

    1983-01-01

    A system is described for acoustically controlled rotation of a levitated object, which avoids deformation of a levitated liquid object. Acoustic waves of the same wavelength are directed along perpendicular directions across the object, and with the relative phases of the acoustic waves repeatedly switched so that one wave alternately leads and lags the other by 90 deg. The amount of torque for rotating the object, and the direction of rotation, are controlled by controlling the proportion of time one wave leads the other and selecting which wave leads the other most of the time.

  2. PRSEUS Acoustic Panel Fabrication

    NASA Technical Reports Server (NTRS)

    Nicolette, Velicki; Yovanof, Nicolette P.; Baraja, Jaime; Mathur, Gopal; Thrash, Patrick; Pickell, Robert

    2011-01-01

    This report describes the development of a novel structural concept, Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS), that addresses the demanding fuselage loading requirements for the Hybrid Wing or Blended Wing Body (BWB) airplane configuration with regards to acoustic response. A PRSEUS panel was designed and fabricated and provided to NASA-LaRC for acoustic response testing in the Structural Acoustics Loads and Transmission (SALT) facility). Preliminary assessments of the sound transmission characteristics of a PRSEUS panel subjected to a representative Hybrid Wing Body (HWB) operating environment were completed for the NASA Environmentally Responsible Aviation (ERA) Program.

  3. Acoustical heat pumping engine

    DOEpatents

    Wheatley, John C.; Swift, Gregory W.; Migliori, Albert

    1983-08-16

    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.

  4. Acoustical heat pumping engine

    DOEpatents

    Wheatley, J.C.; Swift, G.W.; Migliori, A.

    1983-08-16

    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.

  5. An on-line acoustic fluorocarbon coolant mixture analyzer for the ATLAS silicon tracker

    SciTech Connect

    Bates, R.; Battistin, M.; Berry, S.; Bitadze, A.; Bonneau, P.; Bousson, N.; Boyd, G.; Botelho-Direito, J.; DiGirolamo, B.; Doubek, M.; Egorov, K.; Godlewski, J.; Hallewell, G.; Katunin, S.; Mathieu, M.; McMahon, S.; Nagai, K.; Perez-Rodriguez, E.; Rozanov, A.; Vacek, V.; Vitek, M.

    2011-07-01

    The ATLAS silicon tracker community foresees an upgrade from the present octafluoro-propane (C{sub 3}F{sub 8}) evaporative cooling fluid - to a composite fluid with a probable 10-20% admixture of hexafluoro-ethane (C{sub 2}F{sub 6}). Such a fluid will allow a lower evaporation temperature and will afford the tracker silicon substrates a better safety margin against leakage current-induced thermal runaway caused by cumulative radiation damage as the luminosity profile at the CERN Large Hadron Collider increases. Central to the use of this new fluid is a new custom-developed speed-of-sound instrument for continuous real-time measurement of the C{sub 3}F{sub 8}/C{sub 2}F{sub 6} mixture ratio and flow. An acoustic vapour mixture analyzer/flow meter with new custom electronics allowing ultrasonic frequency transmission through gas mixtures has been developed for this application. Synchronous with the emission of an ultrasound 'chirp' from an acoustic transmitter, a fast readout clock (40 MHz) is started. The clock is stopped on receipt of an above threshold sound pulse at the receiver. Sound is alternately transmitted parallel and anti-parallel with the vapour flow for volume flow measurement from transducers that can serve as acoustic transmitters or receivers. In the development version, continuous real-time measurement of C{sub 3}F{sub 8}/C{sub 2}F{sub 6} flow and calculation of the mixture ratio is performed within a graphical user interface developed in PVSS-II, the Supervisory, Control and Data Acquisition standard chosen for LHC and its experiments at CERN. The described instrument has numerous potential applications - including refrigerant leak detection, the analysis of hydrocarbons, vapour mixtures for semiconductor manufacture and anesthetic gas mixtures. (authors)

  6. Improving Accuracy in Detecting Acoustic Onsets

    ERIC Educational Resources Information Center

    Duyck, Wouter; Anseel, Frederik; Szmalec, Arnaud; Mestdagh, Pascal; Tavernier, Antoine; Hartsuiker, Robert J.

    2008-01-01

    In current cognitive psychology, naming latencies are commonly measured by electronic voice keys that detect when sound exceeds a certain amplitude threshold. However, recent research (e.g., K. Rastle & M. H. Davis, 2002) has shown that these devices are particularly inaccurate in precisely detecting acoustic onsets. In this article, the authors…

  7. Acoustics Division recent accomplishments and research plans

    NASA Technical Reports Server (NTRS)

    Clark, L. R.; Morgan, H. G.

    1986-01-01

    The research program currently being implemented by the Acoustics Division of NASA Langley Research Center is described. The scope, focus, and thrusts of the research are discussed and illustrated for each technical area by examples of recent technical accomplishments. Included is a list of publications for the last two calendar years. The organization, staff, and facilities are also briefly described.

  8. Meter scale plasma source for plasma wakefield experiments

    NASA Astrophysics Data System (ADS)

    Vafaei-Najafabadi, N.; Shaw, J. L.; Marsh, K. A.; Joshi, C.; Hogan, M. J.

    2012-12-01

    High accelerating gradients generated by a high density electron beam moving through plasma has been used to double the energy of the SLAC electron beam [1]. During that experiment, the electron current density was high enough to generate its own plasma without significant head erosion. In the newly commissioned FACET facility at SLAC, the peak current will be lower and without pre-ionization, head erosion will be a significant challenge for the planned experiments. In this work we report on our design of a meter scale plasma source for these experiments to effectively avoid the problem of head erosion. The plasma source is based on a homogeneous metal vapor gas column that is generated in a heat pipe oven [2]. A lithium oven over 30 cm long at densities over 1017 cm-3 has been constructed and tested at UCLA. The plasma is then generated by coupling a 10 TW short pulse Ti:Sapphire laser into the gas column using an axicon lens setup. The Bessel profile of the axicon setup creates a region of high intensity that can stretch over the full length of the gas column with approximately constant diameter. In this region of high intensity, the alkali metal vapor is ionized through multi-photon ionization process. In this manner, a fully ionized meter scale plasma of uniform density can be formed. Methods for controlling the plasma diameter and length will also be discussed.

  9. Meter scale plasma source for plasma wakefield experiments

    SciTech Connect

    Vafaei-Najafabadi, N.; Shaw, J. L.; Marsh, K. A.; Joshi, C.; Hogan, M. J.

    2012-12-21

    High accelerating gradients generated by a high density electron beam moving through plasma has been used to double the energy of the SLAC electron beam [1]. During that experiment, the electron current density was high enough to generate its own plasma without significant head erosion. In the newly commissioned FACET facility at SLAC, the peak current will be lower and without pre-ionization, head erosion will be a significant challenge for the planned experiments. In this work we report on our design of a meter scale plasma source for these experiments to effectively avoid the problem of head erosion. The plasma source is based on a homogeneous metal vapor gas column that is generated in a heat pipe oven [2]. A lithium oven over 30 cm long at densities over 10{sup 17} cm{sup -3} has been constructed and tested at UCLA. The plasma is then generated by coupling a 10 TW short pulse Ti:Sapphire laser into the gas column using an axicon lens setup. The Bessel profile of the axicon setup creates a region of high intensity that can stretch over the full length of the gas column with approximately constant diameter. In this region of high intensity, the alkali metal vapor is ionized through multi-photon ionization process. In this manner, a fully ionized meter scale plasma of uniform density can be formed. Methods for controlling the plasma diameter and length will also be discussed.

  10. Acoustic Neuroma Association

    MedlinePlus

    ... Platinum Sponsors More from this sponsor... Platinum Sponsor Gold Sponsor University of Colorado Acoustic Neuroma Program Rocky Mountain Gamma Knife Center Gold Sponsor NYU Langone Medical Center Departments of Neurosurgery ...

  11. Compact acoustic refrigerator

    DOEpatents

    Bennett, Gloria A.

    1992-01-01

    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.

  12. Acoustic imaging system

    DOEpatents

    Smith, Richard W.

    1979-01-01

    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.

  13. Acoustics lecturing in Mexico

    NASA Astrophysics Data System (ADS)

    Beristain, Sergio

    2002-11-01

    Some thirty years ago acoustics lecturing started in Mexico at the National Polytechnic Institute in Mexico City, as part of the Bachelor of Science degree in Communications and Electronics Engineering curricula, including the widest program on this field in the whole country. This program has been producing acoustics specialists ever since. Nowadays many universities and superior education institutions around the country are teaching students at the B.Sc. level and postgraduate level many topics related to acoustics, such as Architectural Acoustics, Seismology, Mechanical Vibrations, Noise Control, Audio, Audiology, Music, etc. Also many institutions have started research programs in related fields, with participation of medical doctors, psychologists, musicians, engineers, etc. Details will be given on particular topics and development.

  14. Compact acoustic refrigerator

    SciTech Connect

    Bennett, G.A.

    1991-12-31

    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.

  15. Compact acoustic refrigerator

    DOEpatents

    Bennett, G.A.

    1992-11-24

    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.

  16. Community Net Energy Metering: How Novel Policies Expand Benefits of Net Metering to Non-Generators

    SciTech Connect

    Rose, James; Varnado, Laurel

    2009-04-01

    As interest in community solutions to renewable energy grows, more states are beginning to develop policies that encourage properties with more than one meter to install shared renewable energy systems. State net metering policies are evolving to allow the aggregation of multiple meters on a customer’s property and to dissolve conventional geographical boundaries. This trend means net metering is expanding out of its traditional function as an enabling incentive to offset onsite customer load at a single facility. This paper analyzes community net energy metering (CNEM) as an emerging vehicle by which farmers, neighborhoods, and municipalities may more easily finance and reap the benefits of renewable energy. Specifically, it aims to compare and contrast the definition of geographical boundaries among different CNEM models and examine the benefits and limitations of each approach. As state policies begin to stretch the geographic boundaries of net metering, they allow inventive solutions to encourage renewable energy investment. This paper attempts to initiate the conversation on this emerging policy mechanism and offers recommendations for further development of these policies.

  17. Mars Acoustic Anemometer

    NASA Astrophysics Data System (ADS)

    Banfield, D. J.

    2012-12-01

    We have developed a very high performance anemometer (wind gauge) for use at Mars. This instrument has great scientific as well as strategic reasons to be included on all future missions to the surface of Mars. We will discuss why we set out to develop this instrument, as well as why the previous wind sensors for Mars are insufficient to meet the scientific and strategic needs at Mars. We will also discuss how the instrument works, and how it differs from terrestrial counterparts. Additionally, we will discuss the current status of the instrument. Measuring winds at Mars is important to better understand the atmospheric circulation at Mars, as well as exchange between the surface and atmosphere. The main conduit of transport of water, and hence its current stability at any particular location on Mars is controlled by these atmospheric motions and the exchange between surface and atmosphere. Mars' large-scale winds are moderately well understood from orbital observations, but the interaction with the surface can only be addressed adequately in situ. Previous anemometers have been 2-D (with the exception of REMS on MSL) and slow response (typically <1Hz), and relatively low sensitivity/accuracy (>1 m/s). Our instrument is capable of fully 3-D measurements, with fast response (>20 Hz) and great sensitivity/accuracy (~3 cm/s). This significant step forward in performance is important for the surface-atmosphere exchanges of heat, momentum and volatiles. In particular, our instrument could directly measure the heat and momentum fluxes between surface and atmosphere using eddy-flux techniques proven terrestrially. When combined with a fast response volatile analysis instrument (e.g., a TLS) we can also measure eddy fluxes of volatile transport. Such a study would be nearly impossible to carry out with preceding anemometers sent to Mars with insufficient response time and sensitivity to adequately sample the turbulent eddies. Additionally, our instrument, using acoustics

  18. Numerical Techniques in Acoustics

    NASA Technical Reports Server (NTRS)

    Baumeister, K. J. (Compiler)

    1985-01-01

    This is the compilation of abstracts of the Numerical Techniques in Acoustics Forum held at the ASME's Winter Annual Meeting. This forum was for informal presentation and information exchange of ongoing acoustic work in finite elements, finite difference, boundary elements and other numerical approaches. As part of this forum, it was intended to allow the participants time to raise questions on unresolved problems and to generate discussions on possible approaches and methods of solution.

  19. Wavefront modulation and subwavelength diffractive acoustics with an acoustic metasurface.

    PubMed

    Xie, Yangbo; Wang, Wenqi; Chen, Huanyang; Konneker, Adam; Popa, Bogdan-Ioan; Cummer, Steven A

    2014-01-01

    Metasurfaces are a family of novel wavefront-shaping devices with planar profile and subwavelength thickness. Acoustic metasurfaces with ultralow profile yet extraordinary wave manipulating properties would be highly desirable for improving the performance of many acoustic wave-based applications. However, designing acoustic metasurfaces with similar functionality to their electromagnetic counterparts remains challenging with traditional metamaterial design approaches. Here we present a design and realization of an acoustic metasurface based on tapered labyrinthine metamaterials. The demonstrated metasurface can not only steer an acoustic beam as expected from the generalized Snell's law, but also exhibits various unique properties such as conversion from propagating wave to surface mode, extraordinary beam-steering and apparent negative refraction through higher-order diffraction. Such designer acoustic metasurfaces provide a new design methodology for acoustic signal modulation devices and may be useful for applications such as acoustic imaging, beam steering, ultrasound lens design and acoustic surface wave-based applications. PMID:25418084

  20. Fuel cell membrane hydration and fluid metering

    DOEpatents

    Jones, Daniel O.; Walsh, Michael M.

    1999-01-01

    A hydration system includes fuel cell fluid flow plate(s) and injection port(s). Each plate has flow channel(s) with respective inlet(s) for receiving respective portion(s) of a given stream of reactant fluid for a fuel cell. Each injection port injects a portion of liquid water directly into its respective flow channel in order to mix its respective portion of liquid water with the corresponding portion of the stream. This serves to hydrate at least corresponding part(s) of a given membrane of the corresponding fuel cell(s). The hydration system may be augmented by a metering system including flow regulator(s). Each flow regulator meters an injecting at inlet(s) of each plate of respective portions of liquid into respective portion(s) of a given stream of fluid by corresponding injection port(s).

  1. Fuel cell membrane hydration and fluid metering

    DOEpatents

    Jones, Daniel O.; Walsh, Michael M.

    2003-01-01

    A hydration system includes fuel cell fluid flow plate(s) and injection port(s). Each plate has flow channel(s) with respective inlet(s) for receiving respective portion(s) of a given stream of reactant fluid for a fuel cell. Each injection port injects a portion of liquid water directly into its respective flow channel. This serves to hydrate at least corresponding part(s) of a given membrane of the corresponding fuel cell(s). The hydration system may be augmented by a metering system including flow regulator(s). Each flow regulator meters an injecting at inlet(s) of each plate of respective portions of liquid into respective portion(s) of a given stream of fluid by corresponding injection port(s).

  2. Optimized profiles for incompressible flow metering nozzles

    NASA Astrophysics Data System (ADS)

    Lakshminarayanan, R.; Haji-Sheikh, A.; Lou, D. Y. S.; Spindler, M.

    1988-04-01

    The Euler-Lagrange equation was used to minimize shear stress in designing a flow-metering nozzle. The flow field in the nozzle was computed by solving the momentum equation in integral form. The profile of the nozzle was obtained by minimizing the shear losses in the converging section of the nozzle. Following computation of the profile, a metering nozzle was designed, constructed, and subsequently tested to evaluate the validity of the analysis. The nozzle was designed for a pipe diameter of 15.24 cm (6 in.) and a throat diameter of 9.266 cm (3.648 in.). The test results indicated a marked increase in the value of the discharge coefficient when it is compared with that for the ASME standard nozzle. The computed pressure distribution is in good agreement with the experimental data.

  3. Smart data acquisition system for utilities metering

    NASA Astrophysics Data System (ADS)

    Ileana, I.; Risteiu, M.; Tulbure, A.; Rusu, M.

    2009-01-01

    The paper approaches the task of automatically reading and recognition of registered data on the utility meters of the users and is a part of a more complex project of our team concerning the remote data acquisition from industrial processes. A huge amount of utility meters in our country is of mechanical type without remote acquiring facilities and as an intermediate solution we propose an intelligent optical acquisition system which will store the read values in desktop and mobile devices. The main requirements of such a system are: portability, data reading accuracy, fast processing and energy independence. The paper analyses several solutions (including Artificial Neural Networks approach) tested by our team and present the experimental results and our conclusions.

  4. Forty Meters from Entry to Victoria Crater

    NASA Technical Reports Server (NTRS)

    2007-01-01

    NASA's Mars Exploration Rover Opportunity used its navigation camera during the rover's 1,278th Martian day, or sol, (Aug. 28, 2007) to take the images combined into this view. The rover was perched at the lip of Victoria Crater, which is about 800 meters (one-half mile) in diameter.

    After assessment of possible routes for Opportunity to descend into the crater, the rover team selected a site farther to the right along the rim. That selected entry point lies near the ripple of bright soil visible just outside the crater near the top center of this scene. The driving distance for Opportunity from the Sol 1,278 viewpoint to the selected entry point is about 40 meters (about 130 feet).

    This view is presented as a cylindrical projection with geometric seam correction.

  5. SOLVENT DISPERSION AND FLOW METER CALCULATION RESULTS

    SciTech Connect

    Nash, C.; Fondeur, F.; Peters, T.

    2013-06-21

    Savannah River National Laboratory (SRNL) found that the dispersion numbers for the six combinations of CSSX:Next Generation Solvent (NGS) “blend” and pure NGS versus salt solution, caustic wash, and strip aqueous solutions are all good. The dispersion numbers are indications of processability with centrifugal contactors. A comparison of solvent physical and thermal properties shows that the Intek™ solvent flow meter in the plant has a reading biased high versus calibrated flow when NGS is used, versus the standard CSSX solvent. The flow meter, calibrated for CSSX solvent, is predicted to read 2.8 gpm of NGS in a case where the true flow of NGS is 2.16 gpm.

  6. Acoustic detection of pneumothorax

    NASA Astrophysics Data System (ADS)

    Mansy, Hansen A.; Royston, Thomas J.; Balk, Robert A.; Sandler, Richard H.

    2003-04-01

    This study aims at investigating the feasibility of using low-frequency (<2000 Hz) acoustic methods for medical diagnosis. Several candidate methods of pneumothorax detection were tested in dogs. In the first approach, broadband acoustic signals were introduced into the trachea during end-expiration and transmitted waves were measured at the chest surface. Pneumothorax was found to consistently decrease pulmonary acoustic transmission in the 200-1200-Hz frequency band, while less change was observed at lower frequencies (p<0.0001). The ratio of acoustic energy between low (<220 Hz) and mid (550-770 Hz) frequency bands was significantly different in the control (healthy) and pneumothorax states (p<0.0001). The second approach measured breath sounds in the absence of an external acoustic input. Pneumothorax was found to be associated with a preferential reduction of sound amplitude in the 200- to 700-Hz range, and a decrease of sound amplitude variation (in the 300 to 600-Hz band) during the respiration cycle (p<0.01 for each). Finally, chest percussion was implemented. Pneumothorax changed the frequency and decay rate of percussive sounds. These results imply that certain medical conditions may be reliably detected using appropriate acoustic measurements and analysis. [Work supported by NIH/NHLBI #R44HL61108.

  7. Ocean acoustic reverberation tomography.

    PubMed

    Dunn, Robert A

    2015-12-01

    Seismic wide-angle imaging using ship-towed acoustic sources and networks of ocean bottom seismographs is a common technique for exploring earth structure beneath the oceans. In these studies, the recorded data are dominated by acoustic waves propagating as reverberations in the water column. For surveys with a small receiver spacing (e.g., <10 km), the acoustic wave field densely samples properties of the water column over the width of the receiver array. A method, referred to as ocean acoustic reverberation tomography, is developed that uses the travel times of direct and reflected waves to image ocean acoustic structure. Reverberation tomography offers an alternative approach for determining the structure of the oceans and advancing the understanding of ocean heat content and mixing processes. The technique has the potential for revealing small-scale ocean thermal structure over the entire vertical height of the water column and along long survey profiles or across three-dimensional volumes of the ocean. For realistic experimental geometries and data noise levels, the method can produce images of ocean sound speed on a smaller scale than traditional acoustic tomography. PMID:26723303

  8. 1-meter near-infrared solar telescope

    NASA Astrophysics Data System (ADS)

    Liu, Z.; Xu, J.

    In order to observe the fine structure of solar dynamical field and magnetic field, a 1-meter near-infrared solar telescope was developed by Yunnan Astronomical Observatory, Chinese Academy of Sciences. The telescope is located by the Fuxian Lake in southwest China. In this paper, we will introduce some details of the telescope such as scientific goals, structures, instruments and the parameters of the site. First light observation of high resolution photosphere is introduced too.

  9. From Smart Metering to Smart Grid

    NASA Astrophysics Data System (ADS)

    Kukuča, Peter; Chrapčiak, Igor

    2016-06-01

    The paper deals with evaluation of measurements in electrical distribution systems aimed at better use of data provided by Smart Metering systems. The influence of individual components of apparent power on the power loss is calculated and results of measurements under real conditions are presented. The significance of difference between the traditional and the complex evaluation of the electricity consumption efficiency by means of different definitions of the power factor is illustrated.

  10. Device Stores and Discharges Metered Fluid

    NASA Technical Reports Server (NTRS)

    Hooper, S. L.; Setzer, D.

    1983-01-01

    Hand-held container accepts measured amount of liquid from pressurized supply. Supply pressure drives spring-loaded piston that stores enough mechanical energy to discharge measured liquid into another container. Original application of container was to rehydrate sterilized pre-packaged food in zerogravity environment of space vehicles. Possible terrestrial applicatios include dispensing of toxic fluids or metering of fluids for household, commercial or laboratory uses.

  11. Fabrication of 4-meter class astronomical optics

    NASA Astrophysics Data System (ADS)

    Valente, M. J.; Kim, D. W.; Oh, C. J.; Novak, M. J.; Burge, J. H.

    2010-07-01

    The 8-meter mirror production capacity at the University of Arizona is well known. As the Arizona Stadium facility is occupied with giant mirrors, we have developed capability for grinding, polishing, and testing 4-m mirrors in the large optics shop in the College of Optical Sciences. Several outstanding capabilities for optics up to 4.3 meters in diameter are in place: A 4.3-m computer controlled grinding and polishing machine allows efficient figuring of steeply aspheric and nonaxisymmetric surfaces. Interferometry (IR and visible wavelengths) and surface profilometry making novel use of a laser tracker allows quick, accurate in-process measurements from a movable platform on a 30-m vertical tower. A 2-meter class flat measured with a 1-m vibration insensitive Fizeau interferometer and scanning pentaprism system; stitching of 1-m sub-apertures provides complete surface data with the technology ready for extension to the 4 m level. These methods were proven successful by completion of several optics including the 4.3-m Discovery Channel Telescope primary mirror. The 10 cm thick ULE substrate was ground and polished to 16 nm rms accuracy, corresponding to 80% encircled energy in 0.073 arc-second, after removing low order bending modes. The successful completion of the DCT mirror demonstrates the engineering and performance of the support system, ability to finish large aspheric surfaces using computer controlled polishing, and accuracy verification of surface measurements. In addition to the DCT mirror, a 2-meter class flat was produced to an unprecedented accuracy of <10 nm-rms, demonstrating the combined 1-m Fizeau interferometer and scanning pentaprism measurement techniques.

  12. Rapid Acoustic Survey for Biodiversity Appraisal

    PubMed Central

    Sueur, Jérôme; Pavoine, Sandrine; Hamerlynck, Olivier; Duvail, Stéphanie

    2008-01-01

    Biodiversity assessment remains one of the most difficult challenges encountered by ecologists and conservation biologists. This task is becoming even more urgent with the current increase of habitat loss. Many methods–from rapid biodiversity assessments (RBA) to all-taxa biodiversity inventories (ATBI)–have been developed for decades to estimate local species richness. However, these methods are costly and invasive. Several animals–birds, mammals, amphibians, fishes and arthropods–produce sounds when moving, communicating or sensing their environment. Here we propose a new concept and method to describe biodiversity. We suggest to forego species or morphospecies identification used by ATBI and RBA respectively but rather to tackle the problem at another evolutionary unit, the community level. We also propose that a part of diversity can be estimated and compared through a rapid acoustic analysis of the sound produced by animal communities. We produced α and β diversity indexes that we first tested with 540 simulated acoustic communities. The α index, which measures acoustic entropy, shows a logarithmic correlation with the number of species within the acoustic community. The β index, which estimates both temporal and spectral dissimilarities, is linearly linked to the number of unshared species between acoustic communities. We then applied both indexes to two closely spaced Tanzanian dry lowland coastal forests. Indexes reveal for this small sample a lower acoustic diversity for the most disturbed forest and acoustic dissimilarities between the two forests suggest that degradation could have significantly decreased and modified community composition. Our results demonstrate for the first time that an indicator of biological diversity can be reliably obtained in a non-invasive way and with a limited sampling effort. This new approach may facilitate the appraisal of animal diversity at large spatial and temporal scales. PMID:19115006

  13. High-Resolution Gas Metering and Nonintrusive Appliance Load Monitoring System

    NASA Astrophysics Data System (ADS)

    Tewolde, Mahder

    This thesis deals with design and implementation of a high-resolution metering system for residential natural gas meters. Detailed experimental measurements are performed on the meter to characterize and understand its measurement properties. Results from these experiments are used to develop a simple, fast and accurate technique to non-intrusively monitor the gas consumption of individual appliances in homes by resolving small amounts of gas usage. The technique is applied on an existing meter retrofitted with a module that includes a high-resolution encoder to collect gas flow data and a microprocessor to analyze and identify appliance load profiles. This approach provides a number of appealing features including low cost, easy installation and integration with automated meter reading (AMR) systems. The application of this method to residential gas meters currently deployed is also given. This is done by performing a load simulation on realistic gas loads with the aim of identifying the necessary parameters that minimize the cost and complexity of the mechanical encoder module. The primary benefits of the system are efficiency analysis, appliance health monitoring and real-time customer feedback of gas usage. Additional benefits of include the ability to detect very small leaks and theft. This system has the potential for wide scale market adoption.

  14. Tracking marine mammals using passive acoustics

    NASA Astrophysics Data System (ADS)

    Nosal, Eva-Marie

    2007-12-01

    It is difficult to study the behavior and physiology of marine mammals or to understand and mitigate human impact on them because much of their lives are spent underwater. Since sound propagates for long distances in the ocean and since many cetaceans are vocal, passive acoustics is a valuable tool for studying and monitoring their behavior. After a brief introduction to and review of passive acoustic tracking methods, this dissertation develops and applies two new methods. Both methods use widely-spaced (tens of kilometers) bottom-mounted hydrophone arrays, as well as propagation models that account for depth-dependent sound speed profiles. The first passive acoustic tracking method relies on arrival times of direct and surface-reflected paths. It is used to track a sperm whale using 5 at the Atlantic Undersea Test and Evaluation Center (AUTEC) and gives position estimates that are accurate to within 10 meters. With such accuracy, the whale's pitch and yaw are estimated by assuming that its main axis (which points from the tail to the rostrum) is parallel to its velocity. Roll is found by fitting the details of the pulses within each sperm whale click to the so-called bent horn model of sperm whale sound production. Finally, given the position and orientation of the whale, its beam pattern is reconstructed and found to be highly directional with an intense forward directed component. Pair-wise spectrogram (PWS) processing is the second passive acoustic tracking method developed in this dissertation. Although it is computationally more intensive, PWS has several advantages over arrival-time tracking methods, especially in shallow water environments, for long duration calls, and for multiple-animal datasets, as is the case for humpback whales on Hawaiian breeding grounds. Results of simulations with realistic noise conditions and environmental mismatch are given and compared to other passive localization techniques. When applied to the AUTEC sperm whale dataset, PWS

  15. Acoustic calibration apparatus for calibrating plethysmographic acoustic pressure sensors

    NASA Technical Reports Server (NTRS)

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

    1995-01-01

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

  16. Characterizing Ocean Turbulence from Argo, Acoustic Doppler, and Simulation Data

    NASA Astrophysics Data System (ADS)

    McCaffrey, Katherine

    Turbulence is inherently chaotic and unsteady, so observing it and modeling it are no easy tasks. The ocean's sheer size makes it even more difficult to observe, and its unpredictable and ever-changing forcings introduce additional complexities. Turbulence in the oceans ranges from basin scale to the scale of the molecular viscosity. The method of energy transfer between scales is, however, an area of active research, so observations of the ocean at all scales are crucial to understanding the basic dynamics of its motions. In this collection of work, I use a variety of datasets to characterize a wide range of scales of turbulence, including observations from multiple instruments and from models with different governing equations. I analyzed the largest scales of the turbulent range using the global salinity data of the Argo profiling float network. Taking advantage of the scattered and discontinuous nature of this dataset, the second-order structure function was calculated down to 2000m depth, and shown to be useful for predicting spectral slopes. Results showed structure function slopes of 2/3 at small scales, and 0 at large scales, which corresponds with spectral slopes of -5/3 at small scales, and -1 at large scales. Using acoustic Doppler velocity measurements, I characterized the meter- to kilometer-scale turbulence at a potential tidal energy site in the Puget Sound, WA. Acoustic Doppler current profiler (ADCP) and acoustic Doppler velocimeter (ADV) observations provided the data for an analysis that includes coherence, anisotropy, and intermittency. In order to more simply describe these features, a parameterization was done with four turbulence metrics, and the anisotropy magnitude, introduced here, was shown to most closely capture the coherent events. Then, using both the NREL TurbSim stochastic turbulence generator and the NCAR large-eddy simulation (LES) model, I calculated turbulence statistics to validate the accuracy of these methods in reproducing

  17. Acoustic tracking of woodhead seabed drifters

    NASA Technical Reports Server (NTRS)

    Mayhue, R. J.; Lovelady, R. W.

    1977-01-01

    An investigation was conducted to determine the feasibility of tracking Woodhead seabed drifters that were instrumented with miniature acoustic transmitters having a range in water in excess of 1.0 n.mi. A trial cruise at the entrance of Delaware Bay, with the R.V. Annandale as the sonar-tracking vessel, verified acoustic communications and positioning of the bottom drifters. A demonstration cruise with the R.V. Annandale was also performed in the New York Bight to attempt to collect information on bottom water movement near the sewage-sluge dump site. Results from the tracking mission in the New York Bight suggested that bottom water currents were negligible near the dump site during the time interval from November 7-12, 1975, and that shipboard sonar tracking of acoustic Woodhead seabed drifters could provide useful Lagragian information on bottom water movement caused by tidal and other nonstorm effects.

  18. Acoustical design of the new Cathay Pacific first class lounge

    NASA Astrophysics Data System (ADS)

    Hong, Westwood K. W.

    Cathay Pacific Airways' requirement of a first class lounge for attracting the high-yield passenger market to Hong Kong presented a special challenge for the Acoustical consultant. The 500-seating lounge covers more than 2000 square meters and is claimed by Cathay to be the biggest in Asia for its first class passengers. Arup acoustics was required to design a space that provided a quiet and relaxed environment for the Commercial Important Persons after a 16 to 17-hour flight. Arup Acoustics has designed the acoustics of the Lounge in meeting a stringent low noise specification requested by the user. The design work gave a comprehensive service both to support the lead consultant Ova Arup & Partners in controlling the external aircraft noise and internal noise and to assist the architect and interior designer in providing an excellent acoustical atmosphere for the passengers to rest while waiting for an onward connection. This paper will discuss the design of the lightweight roof and special double glazing system, featured by a 20-mm-thick laminated glass for the outer pane and a 600 to 1000-mm air gap to combat aircraft noise at the Hong Kong International Airport.

  19. Virtual Acoustics: Evaluation of Psychoacoustic Parameters

    NASA Technical Reports Server (NTRS)

    Begault, Durand R.; Null, Cynthia H. (Technical Monitor)

    1997-01-01

    Current virtual acoustic displays for teleconferencing and virtual reality are usually limited to very simple or non-existent renderings of reverberation, a fundamental part of the acoustic environmental context that is encountered in day-to-day hearing. Several research efforts have produced results that suggest that environmental cues dramatically improve perceptual performance within virtual acoustic displays, and that is possible to manipulate signal processing parameters to effectively reproduce important aspects of virtual acoustic perception in real-time. However, the computational resources for rendering reverberation remain formidable. Our efforts at NASA Ames have been focused using a several perceptual threshold metrics, to determine how various "trade-offs" might be made in real-time acoustic rendering. This includes both original work and confirmation of existing data that was obtained in real rather than virtual environments. The talk will consider the importance of using individualized versus generalized pinnae cues (the "Head-Related Transfer Function"); the use of head movement cues; threshold data for early reflections and late reverberation; and consideration of the necessary accuracy for measuring and rendering octave-band absorption characteristics of various wall surfaces. In addition, a consideration of the analysis-synthesis of the reverberation within "everyday spaces" (offices, conference rooms) will be contrasted to the commonly used paradigm of concert hall spaces.

  20. Synthetic aperture acoustic imaging of canonical targets with a 2-15 kHz linear FM chirp

    NASA Astrophysics Data System (ADS)

    Vignola, Joseph F.; Judge, John A.; Good, Chelsea E.; Bishop, Steven S.; Gugino, Peter M.; Soumekh, Mehrdad

    2011-06-01

    Synthetic aperture image reconstruction applied to outdoor acoustic recordings is presented. Acoustic imaging is an alternate method having several military relevant advantages such as being immune to RF jamming, superior spatial resolution, capable of standoff side and forward-looking scanning, and relatively low cost, weight and size when compared to 0.5 - 3 GHz ground penetrating radar technologies. Synthetic aperture acoustic imaging is similar to synthetic aperture radar, but more akin to synthetic aperture sonar technologies owing to the nature of longitudinal or compressive wave propagation in the surrounding acoustic medium. The system's transceiver is a quasi mono-static microphone and audio speaker pair mounted on a rail 5meters in length. Received data sampling rate is 80 kHz with a 2- 15 kHz Linear Frequency Modulated (LFM) chirp, with a pulse repetition frequency (PRF) of 10 Hz and an inter-pulse period (IPP) of 50 milliseconds. Targets are positioned within the acoustic scene at slant range of two to ten meters on grass, dirt or gravel surfaces, and with and without intervening metallic chain link fencing. Acoustic image reconstruction results in means for literal interpretation and quantifiable analyses. A rudimentary technique characterizes acoustic scatter at the ground surfaces. Targets within the acoustic scene are first digitally spotlighted and further processed, providing frequency and aspect angle dependent signature information.