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Note: This page contains sample records for the topic "radar doppler spectra" from the National Library of EnergyBeta (NLEBeta).
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they are not comprehensive nor are they the most current set.
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to obtain the most current and comprehensive results.


1

Mixed-Phase Cloud Retrievals Using Doppler Radar Spectra  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Mixed-Phase Cloud Retrievals Using Mixed-Phase Cloud Retrievals Using Doppler Radar Spectra M. D. Shupe, S. Y. Matrosov, and T. L. Schneider National Oceanic and Atmospheric Administration Environmental Technology Laboratory Boulder, Colorado P. Kollias Rosentiel School of Marine Atmospheric Sciences University of Miami Miami, Florida Introduction The radar Doppler spectrum contains a wealth of information on cloud microphysical properties. Typically, radar-based cloud retrievals use only the zeroth or first moments of the Doppler spectrum - reflectivity and mean Doppler velocity - to derive quantities such as cloud water content and particle characteristic size (e.g., Liou and Sassen 1994; Matrosov et al. 2002). When using only the moments of the Doppler spectrum, important spectral information can be lost, particularly when the spectrum is

2

Cloud radar Doppler spectra in drizzling stratiform clouds: 2. Observations and microphysical modeling of drizzle evolution  

E-Print Network [OSTI]

Cloud radar Doppler spectra in drizzling stratiform clouds: 2. Observations and microphysical I, the influence of cloud microphysics and dynamics on the shape of cloud radar Doppler spectra in warm stratiform clouds was discussed. The traditional analysis of radar Doppler moments was extended

3

Cloud radar Doppler spectra in drizzling stratiform clouds: 1. Forward modeling and remote sensing applications  

E-Print Network [OSTI]

Cloud radar Doppler spectra in drizzling stratiform clouds: 1. Forward modeling and remote sensing broadening and drizzle growth in shallow liquid clouds remain not well understood. Detailed, cloudscale. Profiling, millimeterwavelength (cloud) radars can provide such observations. In particular, the first three

4

On Deriving Vertical Air Motions from Cloud Radar Doppler Spectra MATTHEW D. SHUPE  

E-Print Network [OSTI]

on a statistical comparison of four cases comprising nearly 6 h of data. Turbulent dissipation rate comparisons multiple ground-based remote sensors. Corrections for Doppler spectrum broadening due to turbulence, wind the Department of Energy (DOE) Atmospheric Radiation Measurement Program's (ARM) site in Barrow, Alaska, during

5

Wind Speeds in Two Tornadic Storms and a Tornado, Deduced from Doppler Spectra  

Science Journals Connector (OSTI)

Doppler spectra of a tornado were collected with a radar having a large unambiguous velocity range, ±91 m s?1. Thus for the first time a presentation of nonaliased spectra was possible, showing direct measurement of radial velocities. By fitting ...

Dusan Zrnic; Michael Istok

1980-12-01T23:59:59.000Z

6

Using doppler radar images to estimate aircraft navigational heading error  

DOE Patents [OSTI]

A yaw angle error of a motion measurement system carried on an aircraft for navigation is estimated from Doppler radar images captured using the aircraft. At least two radar pulses aimed at respectively different physical locations in a targeted area are transmitted from a radar antenna carried on the aircraft. At least two Doppler radar images that respectively correspond to the at least two transmitted radar pulses are produced. These images are used to produce an estimate of the yaw angle error.

Doerry, Armin W. (Albuquerque, NM); Jordan, Jay D. (Albuquerque, NM); Kim, Theodore J. (Albuquerque, NM)

2012-07-03T23:59:59.000Z

7

Gust Front Characteristics as Detected by Doppler Radar  

Science Journals Connector (OSTI)

Gust fronts produce low altitude wind shear that can be hazardous to aircraft operations, especially during takeoff and landing. Radar meteorologists have long been able to identify gust front signatures in Doppler radar data, but in order to use ...

Diana L. Klingle; David R. Smith; Marilyn M. Wolfson

1987-05-01T23:59:59.000Z

8

E-Print Network 3.0 - airborne doppler radar Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

during the austral summer. The study uses Doppler radar data... to understand this phenomenol- ogy because the convection was sampled by ship and aircraft Doppler radars over......

9

Doppler Radar Wind Profiles Iwan Holleman (holleman@knmi.nl)  

E-Print Network [OSTI]

is required before it can be presented to users or assimilated into numerical weather prediction (NWP) models Institute (KNMI), The Netherlands ABSTRACT Doppler weather radars can be employed to determine wind profiles profiles has been performed at KNMI. The verification results indicate that weather radars can provide high

Stoffelen, Ad

10

The Accuracy of Radar Estimates of Ice Terminal Fall Speed from Vertically Pointing Doppler Radar Measurements  

Science Journals Connector (OSTI)

Doppler radar measurements at different frequencies (50 and 2835 MHz) are used to characterize the terminal fall speed of hydrometeors and the vertical air motion in tropical ice clouds and to evaluate statistical methods for retrieving these two ...

Alain Protat; Christopher R. Williams

2011-10-01T23:59:59.000Z

11

KuROS: A New Airborne Ku-Band Doppler Radar for Observation of Surfaces  

Science Journals Connector (OSTI)

This study presents the new airborne Doppler radar Ku-Band Radar for Observation of Surfaces (KuROS), which provides measurements of the normalized radar cross section ?° and of the Doppler velocity over the sea. The system includes two antennas ...

Gérard Caudal; Danièle Hauser; René Valentin; Christophe Le Gac

2014-10-01T23:59:59.000Z

12

Using Doppler spectra to separate hydrometeor populations and analyze ice precipitation in multilayered mixed-phase clouds  

SciTech Connect (OSTI)

Multimodality of cloud radar Doppler spectra is used to partition cloud particle phases and to separate distinct ice populations in the radar sample volume, thereby facilitating analysis of individual ice showers in multilayered mixed-phase clouds. A 35-GHz cloud radar located at Barrow, Alaska, during the Mixed-Phase Arctic Cloud Experiment collected the Doppler spectra. Data from a pair of collocated depolarization lidars confirmed the presence of two liquid cloud layers reported in this study. Surprisingly, both of these cloud layers were embedded in ice precipitation yet maintained their liquid. Our spectral separation of the ice precipitation yielded two distinct ice populations: ice initiated within the two liquid cloud layers and ice precipitation formed in higher cloud layers. Comparisons of ice fall velocity versus radar reflectivity relationships derived for distinct showers reveal that a single relationship might not properly represent the ice showers during this period.

Rambukkange, Mahlon P.; Verlinde, J.; Eloranta, E. W.; Flynn, Connor J.; Clothiaux, Eugene E.

2011-01-31T23:59:59.000Z

13

Radar echo, Doppler Effect and Radar detection in the uniformly accelerated reference frame  

E-Print Network [OSTI]

The uniformly accelerated reference frame described by Hamilton, Desloge and Philpott involves the observers who perform the hyperbolic motion with constant proper acceleration gi. They start to move from different distances measured from the origin O of the inertial reference frame K(XOY), along its OX axis with zero initial velocity. Equipped with clocks and light sources they are engaged with each other in Radar echo, Doppler Effect and Radar detection experiments. They are also engaged in the same experiments with an inertial observer at rest in K(XOY) and located at its origin O. We derive formulas that account for the experiments mentioned above. We study also the landing conditions of the accelerating observers on a uniformly moving platform.

Bernhard Rothenstein; Stefan Popescu

2006-09-14T23:59:59.000Z

14

Improvement of Tornado Warnings by Doppler Radar Measurement of Mesocyclone Rotational Kinetic Energy  

Science Journals Connector (OSTI)

A significant improvement in the reliability and timeliness of tornado warnings can be achieved through quantitative measurement by Doppler radar of selected mesocyclone features. The mesocyclone, a midsize circulation found in some of the most ...

Ralph J. Donaldson Jr.; Paul R. Desrochers

1990-06-01T23:59:59.000Z

15

A Millimeter-Wavelength Dual-Polarization Doppler Radar for Cloud and Precipitation Studies  

Science Journals Connector (OSTI)

A pulse Doppler radar system operating at 35 GHz and having full polarization (linear and circular) diversity capability is described. Separate antennas are used for the transmitter and the receiver because this design approach allows better ...

F. Pasqualucci; B. W. Bartram; R. A. Kropfli; W. R. Moninger

1983-05-01T23:59:59.000Z

16

Uncertainties Associated with Combining Airborne and Ground-Based Doppler Radar Data  

Science Journals Connector (OSTI)

Observations with airborne Doppler radar can expand the area of coverage and extend the time a moving weather system can remain under observation. Also, additional analysis methods are possible with the increase in independent estimates of the ...

Peter S. Ray; David P. Jorgensen

1988-04-01T23:59:59.000Z

17

The effect of smoothing the Doppler radar derived wind field on perturbation pressure retrieval  

E-Print Network [OSTI]

THE EFFECT OF SMOOTHING THE DOPPLER RADAR DERIVED WIND FIELD ON PERTURBATION PRESSURE RETRIEVAL A Thesis by GEORGE PHILIP ROSSER, JR. Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirements... for the degree of MASTER OF SCIENCE May 1986 Major Subject: Meteorology THE EFFECT OF SMOOTHING THE DOPPLER RADAR DERIVED WIND FIELD ON PERTURBATION PRESSURE RETRIEVAL A Thesis by GEORGE PHILIP ROSSER, JR. Approved as to style and content by...

Rosser, George Philip

2012-06-07T23:59:59.000Z

18

A Doppler Radar Emulator with an Application to the Detectability of Tornadic Signatures  

E-Print Network [OSTI]

System (ARPS). Several metrics for tornado intensity are examined, including peak Doppler velocity range, if standard metrics such as azimuthal gate-to-gate shear from a single radar are used for detection. 1. Introduction The design of a weather radar system and its scan- ning strategy involves trade

Xue, Ming

19

A Three-Dimensional Variational Data Analysis Method with Recursive Filter for Doppler Radars  

Science Journals Connector (OSTI)

In this paper, a new method of dual-Doppler radar wind analysis based on a three-dimensional variational data assimilation (3DVAR) approach is proposed. In it, a cost function, including background term and radial observation term, is minimized ...

Jidong Gao; Ming Xue; Keith Brewster; Kelvin K. Droegemeier

2004-03-01T23:59:59.000Z

20

Radar target recognition based on micro-Doppler effect  

Science Journals Connector (OSTI)

Mechanical vibration of target structures will modulate the phase function of radar backscattering, and will induce the frequency modulation of returned signals from the target. It generates a side bands of th...

Wei-guang Dong; Yan-jun Li

2008-11-01T23:59:59.000Z

Note: This page contains sample records for the topic "radar doppler spectra" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

ASSIMILATION OF DOPPLER RADAR DATA INTO NUMERICAL WEATHER MODELS  

SciTech Connect (OSTI)

During the year 2008, the United States National Weather Service (NWS) completed an eight fold increase in sampling capability for weather radars to 250 m resolution. This increase is expected to improve warning lead times by detecting small scale features sooner with increased reliability; however, current NWS operational model domains utilize grid spacing an order of magnitude larger than the radar data resolution, and therefore the added resolution of radar data is not fully exploited. The assimilation of radar reflectivity and velocity data into high resolution numerical weather model forecasts where grid spacing is comparable to the radar data resolution was investigated under a Laboratory Directed Research and Development (LDRD) 'quick hit' grant to determine the impact of improved data resolution on model predictions with specific initial proof of concept application to daily Savannah River Site operations and emergency response. Development of software to process NWS radar reflectivity and radial velocity data was undertaken for assimilation of observations into numerical models. Data values within the radar data volume undergo automated quality control (QC) analysis routines developed in support of this project to eliminate empty/missing data points, decrease anomalous propagation values, and determine error thresholds by utilizing the calculated variances among data values. The Weather Research and Forecasting model (WRF) three dimensional variational data assimilation package (WRF-3DVAR) was used to incorporate the QC'ed radar data into input and boundary conditions. The lack of observational data in the vicinity of SRS available to NWS operational models signifies an important data void where radar observations can provide significant input. These observations greatly enhance the knowledge of storm structures and the environmental conditions which influence their development. As the increase in computational power and availability has made higher resolution real-time model simulations possible, the need to obtain observations to both initialize numerical models and verify their output has become increasingly important. The assimilation of high resolution radar observations therefore provides a vital component in the development and utility of numerical model forecasts for both weather forecasting and contaminant transport, including future opportunities to improve wet deposition computations explicitly.

Chiswell, S.; Buckley, R.

2009-01-15T23:59:59.000Z

22

Improving the Model Convective Storm Quantitative Precipitation Nowcasting by Assimilating State Variables Retrieved from Multiple-Doppler Radar Observations  

Science Journals Connector (OSTI)

This research combines an advanced multiple-Doppler radar synthesis technique with the thermodynamic retrieval method, originally proposed by Gal-Chen, and a moisture/temperature adjustment scheme, and formulates a sequential procedure. The focus ...

Yu-Chieng Liou; Jian-Luen Chiou; Wei-Hao Chen; Hsin-Yu Yu

2014-11-01T23:59:59.000Z

23

Cloud Properties from Doppler Radar Spectra - a Growing Suite...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Extraction Algorithms Edward Luke 1 , Pavlos Kollias 2 , Matthew Shupe 3 , Karen Johnson 1 , Eugene Clothiaux 4 1. Brookhaven National Laboratory 2. McGill University 3....

24

Assimilation of T-TREC-Retrieved Winds from Single-Doppler Radar with an Ensemble Kalman Filter for the Forecast of Typhoon Jangmi (2008)  

Science Journals Connector (OSTI)

A tropical cyclone (TC) circulation Tracking Radar Echo by Correlation technique (T-TREC) developed recently is applied to derive horizontal winds from single Doppler radar reflectivity Z data (combined with radial velocity Vr data when available)...

Mingjun Wang; Ming Xue; Kun Zhao; Jili Dong

2014-05-01T23:59:59.000Z

25

Snow growth and transport patterns in orographic storms as estimated from airborne vertical-plane dual-Doppler radar data  

Science Journals Connector (OSTI)

Airborne vertical-plane dual-Doppler cloud radar data, collected on wind-parallel flight legs over a mountain in Wyoming in 16 winter storms, are used to analyze the growth, transport, and sedimentation of snow. In all storms the wind is rather ...

Bart Geerts; Yang Yang; Roy Rasmussen; Samuel Haimov; Binod Pokharel

26

Wind Speed Dependence of Single-Site Wave-Height Retrievals from High-Frequency Radars  

Science Journals Connector (OSTI)

Wave-height observations derived from single-site high-frequency (HF) radar backscattered Doppler spectra are generally recognized to be less accurate than overlapping radar techniques but can provide significantly larger sampling regions. The ...

Brian K. Haus; Lynn K. Shay; Paul A. Work; George Voulgaris; Rafael J. Ramos; Jorge Martinez-Pedraja

2010-08-01T23:59:59.000Z

27

Relativistic Doppler Effect: Universal Spectra and Zeptosecond Pulses  

Science Journals Connector (OSTI)

We report on a numerical observation of the train of zeptosecond pulses produced by the reflection of a relativistically intense femtosecond laser pulse from the oscillating boundary of an overdense plasma because of the Doppler effect. These pulses promise to become unique experimental and technological tools since their length is of the order of the Bohr radius and the intensity is extremely high ?1019??W/cm2. We present the physical mechanism, analytical theory, and direct particle-in-cell simulations. We show that the harmonic spectrum is universal: the intensity of nth harmonic scales as 1/np for n<4?2, where ? is the largest ? factor of the electron fluid boundary, and p=3 and p=5/2 for the broadband and quasimonochromatic laser pulses, respectively.

S. Gordienko; A. Pukhov; O. Shorokhov; T. Baeva

2004-09-10T23:59:59.000Z

28

Relativistic Doppler effect: universal spectra and zeptosecond pulses  

E-Print Network [OSTI]

We report on a numerical observation of the train of zeptosecond pulses produced by reflection of a relativistically intense femtosecond laser pulse from the oscillating boundary of an overdense plasma because of the Doppler effect. These pulses promise to become a unique experimental and technological tool since their length is of the order of the Bohr radius and the intensity is extremely high $\\propto 10^{19}$ W/cm$^2$. We present the physical mechanism, analytical theory, and direct particle-in-cell simulations. We show that the harmonic spectrum is universal: the intensity of $n$th harmonic scales as $1/n^{p}$ for $n < 4\\gamma^2$, where $\\gamma$ is the largest $\\gamma$--factor of the electron fluid boundary, $p=3$ and $p=5/2$ for the broadband and quasimonochromatic laser pulses respectively.

S. Gordienko; A. Pukhov; O. Shorokhov; T. Baeva

2004-05-10T23:59:59.000Z

29

Doppler Effect in Spectra of Positive Rays of Uniform Velocity in Argon, Neon, Helium  

Science Journals Connector (OSTI)

Ions of argon, neon, helium, formed in a low voltage arc have been accelerated to high speeds in a short electric field, forming beams of positive ions which all have the same energy. The spectra of the beams of positive rays of uniform energy observed in the direction of motion show a characteristic Doppler effect, with displaced lines fully as sharp as the rest lines. With the exception of the very intense ?3418 of neon, the arc lines of argon and neon have no Doppler effect, while the lines of the first spark spectrum are accompanied by sharp displaced lines only slightly less intense than the rest lines, whose separation corresponds accurately to the speeds acquired by singly charged ions in the accelerating field, for velocities 9000 to 28,000 volts and several lines of higher spark spectra were observed with displaced lines also corresponding to singly charged ions. Satisfactory observations are made at pressure about 5×10-3 mm, the intensity and sharpness of the displaced lines diminishing with increasing pressure. In helium, the arc lines show relatively faint displaced lines corresponding to singly charged ions; one spark line ?4686 was accompanied by a relatively intense displaced line, while the only other spark line observed, ?4541, had no Doppler effect.

Anna I. McPherson

1933-11-01T23:59:59.000Z

30

Bulk Hook Echo Raindrop Sizes Retrieved Using Mobile, Polarimetric Doppler Radar Observations  

Science Journals Connector (OSTI)

Polarimetric radar observations obtained by the NOAA (NSSL) mobile, X-band, dual-polarization radar (NOXP) are used to investigate hook echo precipitation properties in several tornadic and non-tornadic supercells. Hook echo drop size ...

Michael M. French; Donald W. Burgess; Edward R. Mansell; Louis J. Wicker

31

ON THE IMPACT OF SUPER RESOLUTION WSR-88D DOPPLER RADAR DATA ASSIMILATION ON HIGH RESOLUTION NUMERICAL MODEL FORECASTS  

SciTech Connect (OSTI)

Assimilation of radar velocity and precipitation fields into high-resolution model simulations can improve precipitation forecasts with decreased 'spin-up' time and improve short-term simulation of boundary layer winds (Benjamin, 2004 & 2007; Xiao, 2008) which is critical to improving plume transport forecasts. Accurate description of wind and turbulence fields is essential to useful atmospheric transport and dispersion results, and any improvement in the accuracy of these fields will make consequence assessment more valuable during both routine operation as well as potential emergency situations. During 2008, the United States National Weather Service (NWS) radars implemented a significant upgrade which increased the real-time level II data resolution to 8 times their previous 'legacy' resolution, from 1 km range gate and 1.0 degree azimuthal resolution to 'super resolution' 250 m range gate and 0.5 degree azimuthal resolution (Fig 1). These radar observations provide reflectivity, velocity and returned power spectra measurements at a range of up to 300 km (460 km for reflectivity) at a frequency of 4-5 minutes and yield up to 13.5 million point observations per level in super-resolution mode. The migration of National Weather Service (NWS) WSR-88D radars to super resolution is expected to improve warning lead times by detecting small scale features sooner with increased reliability; however, current operational mesoscale model domains utilize grid spacing several times larger than the legacy data resolution, and therefore the added resolution of radar data is not fully exploited. The assimilation of super resolution reflectivity and velocity data into high resolution numerical weather model forecasts where grid spacing is comparable to the radar data resolution is investigated here to determine the impact of the improved data resolution on model predictions.

Chiswell, S

2009-01-11T23:59:59.000Z

32

Effect of method and parameters of spectral analysis on selected indices of simulated Doppler spectra  

Science Journals Connector (OSTI)

The sensitivity of Doppler spectral indices (mean frequency, maximum frequency, ... bias of spectral estimate has a more important effect on these indices than its variance. A ... FFT method, result in increased ...

K. Kaluzynski; T. Palko

1993-05-01T23:59:59.000Z

33

Simultaneous observations of 46. 8-MHz and 430-MHz radar backscatter from HF-induced ionospheric Langmuir turbulence  

SciTech Connect (OSTI)

Simultaneous high-resolution spectra of the upshifted enhanced plasma line were obtained with the 46.8-MHz and 430-MHz Arecibo radars in the presence of HF transmissions at two closely spaced frequencies. The spectra obtained with the 46.8-MHz radar showed two narrow features with positive Doppler shifts equal to the two closely spaced frequencies of the HF transmissions; all the spectral power was contained in those two narrow features. The spectra obtained with the 430-MHz radar showed a single narrow feature with a positive Doppler shift equal to the arithmetic mean of the same two closely spaced frequencies; the spectral power in that narrow feature contained about 3% of the total spectral power. The present results broadly confirm the tentative interpretation of earlier observations with a 46.8-MHz radar at Arecibo. The results also show the fundamental difference in the physical processes leading to the enhanced plasma line spectra observed with the two radars.

Sulzer, M.P. (Arecibo Observatory (Puerto Rico)); Fejer, J.A. (Univ. of California, San Diego, La Jolla (United States))

1991-10-01T23:59:59.000Z

34

W-band ARM Cloud Radar (WACR) Handbook  

SciTech Connect (OSTI)

The W-band Atmospheric Radiation Measurement (ARM) Program Cloud Radar (WACR) systems are zenith pointing Doppler radars that probe the extent and composition of clouds at 95.04 GHz. The main purpose of this radar is to determine cloud boundaries (e.g., cloud bottoms and tops). This radar reports estimates for the first three spectra moments for each range gate up to 15 km. The 0th moment is reflectivity, the 1st moment is radial velocity, and the 2nd moment is spectral width. Also available are the raw spectra files. Unlike the millimeter wavelength cloud radar (MMCR), the WACR does not use pulse coding and operates in only copolarization and cross-polarization modes.

Widener, KB; Johnson, K

2005-01-05T23:59:59.000Z

35

Analysis of 11 june 2003 mesoscale convective vortex genesis using weather surveillance radar ??88 doppler (wsr-88d)  

E-Print Network [OSTI]

, radar, and surface analysis of the synoptic environment valid at 0000 UTC 11 June 2003????????? 17 1.11. 850 mb WRF 10 km resolution forecast model for 0000 UTC 11 June 2003..??????????????????????.. 18 ix FIGURE... Page 1.12. Surface to 3km wind shear WRF 10 km resolution forecast model for 0000 UTC 11 June 2003???????????????? 19 1.13. 500 mb WRF 10 km resolution forecast model for 0000 UTC 11 June 2003??????????????????????? 20 1.14. 0000 UTC 11...

Reynolds, Amber Elizabeth

2009-05-15T23:59:59.000Z

36

Vibrational spectra of nanowires measured using laser doppler vibrometry and STM studies of epitaxial graphene : an LDRD fellowship report.  

SciTech Connect (OSTI)

A few of the many applications for nanowires are high-aspect ratio conductive atomic force microscope (AFM) cantilever tips, force and mass sensors, and high-frequency resonators. Reliable estimates for the elastic modulus of nanowires and the quality factor of their oscillations are of interest to help enable these applications. Furthermore, a real-time, non-destructive technique to measure the vibrational spectra of nanowires will help enable sensor applications based on nanowires and the use of nanowires as AFM cantilevers (rather than as tips for AFM cantilevers). Laser Doppler vibrometry is used to measure the vibration spectra of individual cantilevered nanowires, specifically multiwalled carbon nanotubes (MWNTs) and silver gallium nanoneedles. Since the entire vibration spectrum is measured with high frequency resolution (100 Hz for a 10 MHz frequency scan), the resonant frequencies and quality factors of the nanowires are accurately determined. Using Euler-Bernoulli beam theory, the elastic modulus and spring constant can be calculated from the resonance frequencies of the oscillation spectrum and the dimensions of the nanowires, which are obtained from parallel SEM studies. Because the diameters of the nanowires studied are smaller than the wavelength of the vibrometer's laser, Mie scattering is used to estimate the lower diameter limit for nanowires whose vibration can be measured in this way. The techniques developed in this thesis can be used to measure the vibrational spectra of any suspended nanowire with high frequency resolution Two different nanowires were measured - MWNTs and Ag{sub 2}Ga nanoneedles. Measurements of the thermal vibration spectra of MWNTs under ambient conditions showed that the elastic modulus, E, of plasma-enhanced chemical vapor deposition (PECVD) MWNTs is 37 {+-} 26 GPa, well within the range of E previously reported for CVD-grown MWNTs. Since the Ag{sub 2}Ga nanoneedles have a greater optical scattering efficiency than MWNTs, their vibration spectra was more extensively studied. The thermal vibration spectra of Ag{sub 2}Ga nanoneedles was measured under both ambient and low-vacuum conditions. The operational deflection shapes of the vibrating Ag{sub 2}Ga nanoneedles was also measured, allowing confirmation of the eigenmodes of vibration. The modulus of the crystalline nanoneedles was 84.3 {+-} 1.0 GPa. Gas damping is the dominate mechanism of energy loss for nanowires oscillating under ambient conditions. The measured quality factors, Q, of oscillation are in line with theoretical predictions of air damping in the free molecular gas damping regime. In the free molecular regime, Q{sub gas} is linearly proportional to the density and diameter of the nanowire and inversely proportional to the air pressure. Since the density of the Ag{sub 2}Ga nanoneedles is three times that of the MWNTs, the Ag{sub 2}Ga nanoneedles have greater Q at atmospheric pressures. Our initial measurements of Q for Ag{sub 2}Ga nanoneedles in low-vacuum (10 Torr) suggest that the intrinsic Q of these nanoneedles may be on the order of 1000. The epitaxial carbon that grows after heating (000{bar 1}) silicon carbide (SiC) to high temperatures (1450-1600) in vacuum was also studied. At these high temperatures, the surface Si atoms sublime and the remaining C atoms reconstruct to form graphene. X-ray photoelectron spectroscopy (XPS) and scanning tunneling microscopy (STM) were used to characterize the quality of the few-layer graphene (FLG) surface. The XPS studies were useful in confirming the graphitic composition and measuring the thickness of the FLG samples. STM studies revealed a wide variety of nanometer-scale features that include sharp carbon-rich ridges, moire superlattices, one-dimensional line defects, and grain boundaries. By imaging these features with atomic scale resolution, considerable insight into the growth mechanisms of FLG on the carbon-face of SiC is obtained.

Biedermann, Laura Butler

2009-09-01T23:59:59.000Z

37

Measuring surface ocean wave height and directional spectra using an Acoustic Doppler Current Profiler from an autonomous underwater vehicle  

E-Print Network [OSTI]

The Acoustic Doppler Current Profiler (ADCP) is a proven technology which is capable of measuring surface wave height and directional information, however it is generally limited to rigid, bottom mounted applications which ...

Haven, Scott

2012-01-01T23:59:59.000Z

38

Doppler characteristics of sea clutter.  

SciTech Connect (OSTI)

Doppler radars can distinguish targets from clutter if the target's velocity along the radar line of sight is beyond that of the clutter. Some targets of interest may have a Doppler shift similar to that of clutter. The nature of sea clutter is different in the clutter and exo-clutter regions. This behavior requires special consideration regarding where a radar can expect to find sea-clutter returns in Doppler space and what detection algorithms are most appropriate to help mitigate false alarms and increase probability of detection of a target. This paper studies the existing state-of-the-art in the understanding of Doppler characteristics of sea clutter and scattering from the ocean to better understand the design and performance choices of a radar in differentiating targets from clutter under prevailing sea conditions.

Raynal, Ann Marie; Doerry, Armin Walter

2010-06-01T23:59:59.000Z

39

Transverse and Longitudinal Doppler Effects of the Sunbeam Spectra and Earth-Self Rotation and Orbital Velocities, the Mass of the Sun and Others  

E-Print Network [OSTI]

The transverse and longitudinal Doppler effects of the sunbeam spectra are shown to result in the earth parameters such as the earth-self rotation and revolution velocities, the earth orbit semi-major axis, the earth orbital angular momentum, the earth axial tilt, the earth orbit eccentricity, the local latitude and the mass of the sun. The sunbeam global positioning scheme is realized, including the earth orbital position. PACS numbers: 91.10.Fc, 95.10.Km, 91.10.Da, 91.10.Jf.

Sang Boo Nam

2009-11-17T23:59:59.000Z

40

Millimeter Wave Cloud Radar (MMCR) Handbook  

SciTech Connect (OSTI)

The millimeter cloud radar (MMCR) systems probe the extent and composition of clouds at millimeter wavelengths. The MMCR is a zenith-pointing radar that operates at a frequency of 35 GHz. The main purpose of this radar is to determine cloud boundaries (e.g., cloud bottoms and tops). This radar will also report radar reflectivity (dBZ) of the atmosphere up to 20 km. The radar possesses a doppler capability that will allow the measurement of cloud constituent vertical velocities.

KB Widener; K Johnson

2005-01-30T23:59:59.000Z

Note: This page contains sample records for the topic "radar doppler spectra" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Cosmology with Doppler Lensing  

E-Print Network [OSTI]

Doppler lensing is the apparent change in object size and magnitude due to peculiar velocities. Objects falling into an overdensity appear larger on its near side, and smaller on its far side, than typical objects at the same redshifts. This effect dominates over the usual gravitational lensing magnification at low redshift. Doppler lensing is a promising new probe of cosmology, and we explore in detail how to utilize the effect with forthcoming surveys. We present cosmological simulations of the Doppler and gravitational lensing effects based on the Millennium simulation. We show that Doppler lensing can be detected around stacked voids or unvirialised over-densities. New power spectra and correlation functions are proposed which are designed to be sensitive to Doppler lensing. We consider the impact of gravitational lensing and intrinsic size correlations on these quantities. We compute the correlation functions and forecast the errors for realistic forthcoming surveys, providing predictions for constraints...

Bacon, David J; Clarkson, Chris; Bolejko, Krzysztof; Maartens, Roy

2014-01-01T23:59:59.000Z

42

W-band ARM Cloud Radar (WACR) Update and Status  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

W-band ARM Cloud Radar (WACR) Update and Status W-band ARM Cloud Radar (WACR) Update and Status PopStefanija, Ivan ProSensing, Inc. Mead, James ProSensing Inc. Widener, Kevin Pacific Northwest National Laboratory Category: Instruments Two W-band ARM Cloud Radars (WACR) have been developed for the SGP and the ARM Mobile Facility (AMF) by ProSensing. The SGP WACR was successfully deployed in the same shelter as the MMCR in 2005. It is currently collecting co-polarization and cross-polarization spectral moments (reflectivity, Doppler velocity, and spectral width) along with spectra data. The AMF WACR will be deployed with the AMF in Niamey, Niger early in 2006. We will present ingested WACR data formats available from the ARM Archive, a selected comparisons of WACR and MMCR data at SGP, and data from

43

Planetary radar astronomy  

Science Journals Connector (OSTI)

Radar is a powerful technique that has furnished otherwise unavailable information about solar system bodies for three decades. The advantages of radar in planetary astronomy result from (1) the observer's control of all the attributes of the coherent signal used to illuminate the target, especially the wave form's time/frequency modulation and polarization; (2) the ability of radar to resolve objects spatially via measurements of the distribution of echo power in time delay and Doppler frequency; (3) the pronounced degree to which delay-Doppler measurements constrain orbits and spin vectors; and (4) centimeter-to-meter wavelengths, which easily penetrate optically opaque planetary clouds and cometary comae, permit investigation of near-surface macrostructure and bulk density, and are sensitive to high concentrations of metal or, in certain situations, ice. Planetary radar astronomy has primarily involved observations with Earth-based radar telescopes, but also includes some experiments with a spaceborne transmitter or receiver. In addition to providing a wealth of information about the geological and dynamical properties of asteroids, comets, the inner planets, and natural satellites, radar experiments have established the scale of the solar system, have contributed significantly to the accuracy of planetary ephemerides, and have helped to constrain theories of gravitation. This review outlines radar astronomical techniques and describes principal observational results.

Steven J. Ostro

1993-10-01T23:59:59.000Z

44

E-Print Network 3.0 - analyzing nexrad doppler Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

using1 Gaussian Scale Mixtures in the Wavelet Domain2 Summary: Mission (TRMM) satellite and ground- based20 NEXRAD weather surveillance Doppler radars.21 1 12......

45

METR 4624--Radar Meteorology SPRING 2012  

E-Print Network [OSTI]

can be purchased at the Bookstore. [Note: This book covers fundamentals at an introductory level. We (1986), and Doppler Radar Meteorological Observations; Federal Meteorological Handbook No. 11 (Part B

Droegemeier, Kelvin K.

46

METR 4624--Radar Meteorology SPRING 2014  

E-Print Network [OSTI]

be purchased at the Bookstore. [Note: This book covers fundamentals at an introductory level. We will go well), and Doppler Radar Meteorological Observations; Federal Meteorological Handbook No. 11 (Part B) (1990). Grades

Droegemeier, Kelvin K.

47

Spatial-temporal mesoscale modelling of rainfall intensity using gage and radar data  

E-Print Network [OSTI]

Spatial-temporal mesoscale modelling of rainfall intensity using gage and radar data Montserrat fields. Doppler radar data offer better spatial and temporal coverage, but Doppler radar measures values. We use spatial logistic regression to model the probability of rain for both sources of data

Reich, Brian J.

48

Sub-Doppler Spectra of Infrared Hyperfine Transitions of Nitric Oxide Using a Pulse Modulated Quantum Cascade Laser: Rapid Passage, Free Induction Decay and the AC Stark Effect  

SciTech Connect (OSTI)

Using a low power, rapid (nsec) pulse-modulated quantum cascade (QC) laser, collective coherent effects in the 5 {micro}m spectrum of nitric oxide have been demonstrated by the observation of sub-Doppler hyperfine splitting and also Autler-Townes splitting of Doppler broadened lines. For nitrous oxide, experiments and model calculations have demonstrated that two main effects occur with ulsemodulated (chirped) quantum cascade lasers: free induction decay signals, and signals induced by rapid passage during the laser chirp. In the open shell molecule, NO, in which both {Lambda}-doubling splitting and hyperfine structure occur, laser field-induced coupling between the hyperfine levels of the two {Lambda}-doublet components can induce a large AC Stark effect. This may be observed as sub-Doppler structure, field-induced splittings, or Autler-Townes splitting of a Doppler broadened line. These represent an extension of the types of behaviour observed in the closed shell molecule nitrous oxide, using the same apparatus, when probed with an 8 {micro}m QC laser.

Duxbury, Geoffrey; Kelly, James F.; Blake, Thomas A.; Langford, Nigel

2012-05-07T23:59:59.000Z

49

Doppler Tomography  

E-Print Network [OSTI]

I review the method of Doppler tomography which translates binary-star line profiles taken at a series of orbital phases into a distribution of emission over the binary. I begin with a discussion of the basic principles behind Doppler tomography, including a comparison of the relative merits of maximum entropy regularisation versus filtered back-projection for implementing the inversion. Following this I discuss the issue of noise in Doppler images and possible methods for coping with it. Then I move on to look at the results of Doppler Tomography applied to cataclysmic variable stars. Outstanding successes to date are the discovery of two-arm spiral shocks in cataclysmic variable accretion discs and the probing of the stream/magnetospheric interaction in magnetic cataclysmic variable stars. Doppler tomography has also told us much about the stream/disc interaction in non-magnetic systems and the irradiation of the secondary star in all systems. The latter indirectly reveals such effects as shadowing by the accretion disc or stream. I discuss all of these and finish with some musings on possible future directions for the method. At the end I include a tabulation of Doppler maps published in refereed journals.

T. R. Marsh

2000-11-01T23:59:59.000Z

50

Measurement of the variance of water surface slopes by a radar: Verification of algorithms  

Science Journals Connector (OSTI)

A full-scale experiment is carried out to study backscattering of a microwave radar signal by a rough water surface during flight over the Gorky water storage. A centimeter-wavelength Doppler radar with a knif...

V. Yu. Karaev; M. B. Kanevsky; E. M. Meshkov…

2008-05-01T23:59:59.000Z

51

ERADERAD 20062006Proceedings ofProceedings of Detecting weather radar clutter  

E-Print Network [OSTI]

ERADERAD 20062006Proceedings ofProceedings of Detecting weather radar clutter using satellite results from investigations into detection of weather radar clutter by data fusion with satellite-based nowcasting products. Weather radar data from three C-band Doppler weather radars of the Danish Meteorological

52

Doppler Effect in Positive Rays of Hydrogen  

Science Journals Connector (OSTI)

... THE Balmer lines in the spectra of the positive rays of hydrogen show Doppler displacement d? given by the relation where ? is the wave-length of the light ... of light. J. Stark1, and J. Stark and Steubing2 showed that whereas the Doppler displacement is not a line but a strip of finite width, the maximum displacement ...

B. DASANNACHARYA; G. K. DAS

1944-07-01T23:59:59.000Z

53

Sandia National Laboratories: TTU Advanced Doppler Radar  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Sediment Transport High-Resolution Computational Algorithms for Simulating Offshore Wind Farms Innovative Offshore Vertical-Axis Wind Turbine Rotors Offshore Publications...

54

Prospects of the WSR-88D Radar for Cloud Studies  

E-Print Network [OSTI]

Sounding of nonprecipitating clouds with the 10-cm wavelength Weather Surveillance Radar-1988 Doppler (WSR-88D) is discussed. Readily available enhancements to signal processing and volume coverage patterns of the WSR-88D allow observations of a...

Melnikov, Valery M.; Zrni?, Dusan S.; Doviak, Richard J.; Chilson, Phillip B.; Mechem, David B.; Kogan, Yefim L.

2011-04-01T23:59:59.000Z

55

Doppler segmentation  

E-Print Network [OSTI]

is then 2 x 10 Hz/sec. With this frequency modulation rate, the 5 usec pulse would obta1n a 100 MHz bandwidth and, from Equation (3. 2), the system would be able to provide a 1. 5 meter range resolut1on. 5. Transmiss1on Power In the previous s1gnal... OF CONTENTS ABSTRACT . ACKNOWLEDGEMENT TABLE OF CONTENTS LIST OF FIGURES CHAPTER I. INTRODUCTION . CHAPTER II. SYSTEM DEVELOPMENT 1. Range Imaging System 2. Range and Velocity Acquisition by Linear FM Pulse . 3. Infrared Range/Doppler Imaging System...

Yeh, Chih-Ping

2012-06-07T23:59:59.000Z

56

Doppler flowmeter  

DOE Patents [OSTI]

A Doppler flowmeter impulses an ultrasonic fixed-frequency signal obliquely into a slurry flowing in a pipe and a reflected signal is detected after having been scattered off of the slurry particles, whereby the shift in frequencies between the signals is proportional to the slurry velocity and hence slurry flow rate. This flowmeter filters the Doppler frequency-shift signal, compares the filtered and unfiltered shift signals in a divider to obtain a ratio, and then further compares this ratio against a preset fractional ratio. The flowmeter utilizes a voltage-to-frequency convertor to generate a pulsed signal having a determinable rate of repetition precisely proportional to the divergence of the ratios. The pulsed signal serves as the input control for a frequency-controlled low-pass filter, which provides thereby that the cutoff frequency of the filtered signal is known. The flowmeter provides a feedback control by minimizing the divergence. With the cutoff frequency and preset fractional ratio known, the slurry velocity and hence flow will also be determinable.

Karplus, H.H.B.; Raptis, A.C.

1981-11-13T23:59:59.000Z

57

Kinematical relations among radar-observed water concentrations, vertical motions, and liquid-water drop-size spectra in convective clouds  

E-Print Network [OSTI]

and liquid- water concentration, a one-dimensional (vertical) continuity equation for water substance is considered. Atmospheric values of parameters which appear in the continuity equation are determined from radar reflectivity measurements. Empirical... viii I INTRODUCTION Cloud Motions in General Equations Governing Cloud Parameters A Kinematical Equation Based on the Continuity of Water Substance Determinati. on of the Values of the Atmospheric Variables Appearing in the Kinematical Equation...

Runnels, Robert Clayton

2012-06-07T23:59:59.000Z

58

Estimation and Mapping of Hurricane Turbulent Energy Using Airborne Doppler Measurements  

Science Journals Connector (OSTI)

Hurricane turbulent kinetic energy (TKE) was computed using airborne Doppler measurements from the NOAA WP-3D tail radars, and TKE data were retrieved for a variety of storms at different stages of their life cycle. The geometry of the radar ...

Sylvie Lorsolo; Jun A. Zhang; Frank Marks Jr.; John Gamache

2010-09-01T23:59:59.000Z

59

Merged and corrected 915 MHz Radar Wind Profiler moments  

DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

The radar wind profiler (RWP) present at the SGP central facility operates at 915 MHz and was reconfigured in early 2011, to collect key sets of measurements for precipitation and boundary layer studies. The RWP is configured to run in two main operating modes: a precipitation (PR) mode with frequent vertical observations and a boundary layer (BL) mode that is similar to what has been traditionally applied to RWPs. To address issues regarding saturation of the radar signal, range resolution and maximum range, the RWP PR mode is set to operate with two different pulse lengths, termed as short pulse (SP) and long pulse (LP). Please refer to the RWP handbook (Coulter, 2012) for further information. Data from the RWP PR-SP and PR-LP modes have been extensively used to study deep precipitating clouds, especially their dynamical structure as the RWP data does not suffer from signal attenuation during these conditions (Giangrande et al., 2013). Tridon et al. (2013) used the data collected during the Mid-latitude Continental Convective Cloud Experiment (MC3E) to improve the estimation of noise floor of the RWP recorded Doppler spectra.

Jonathan Helmus,Virendra Ghate, Frederic Tridon

60

Convective Cells in Altocumulus Observed with a High-Resolution Radar  

Science Journals Connector (OSTI)

Very-high-resolution Doppler radar observations are used together with aircraft measurements to document the dynamic and thermodynamic structure of a dissipating altocumulus cloud system associated with a deep virga layer. The cloud layer ...

Jerome M. Schmidt; Piotr J. Flatau; Robert D. Yates

2014-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "radar doppler spectra" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

The BMRC/NCAR C-Band Polarimetric (C-POL) Radar System  

Science Journals Connector (OSTI)

The development of the first Australian C-band polarimetric/Doppler meteorological radar system (C-POL) is described. Motivated by the need to obtain improved rainfall estimation and the vertical profile of hydrometeors, C-POL was developed ...

T. Keenan; K. Glasson; F. Cummings; T. S. Bird; J. Keeler; J. Lutz

1998-08-01T23:59:59.000Z

62

Angular Doppler effect  

Science Journals Connector (OSTI)

An angular analog of the Doppler effect arising from the quantum of angular momentum carried by circularly polarized photons is presented and developed. Applications to rotational...

Garetz, Bruce A

1981-01-01T23:59:59.000Z

63

Ion temperatures in Ormak from Doppler broadening  

Science Journals Connector (OSTI)

Rapid-scanning spectrometric techniques have permitted the determination of ion temperatures in ORMAK as a function of time during the discharge pulse for ORMAK plasma currents up to 180 kA. Emission spectra of hydrogen atoms are Doppler-broadened in the line wings, characteristic of the initial proton motions prior to charge exchange, and give ion "temperatures" generally less than kT+ ~ 300 eV. Impurity spectra of C III and O V, as well as the spectra of He II in helium discharges, lead to somewhat higher ion temperatures ranging up to a maximum of kT+ ~ 700 eV.

J. Rand McNally Jr.; R.V. Neidigh

1973-01-01T23:59:59.000Z

64

High Accuracy Three-Dimensional Radar Sensor Design based on Fuzzy Logic Control Approach  

E-Print Network [OSTI]

High Accuracy Three-Dimensional Radar Sensor Design based on Fuzzy Logic Control Approach Lilin Guo in target tracking. Furthermore, a fuzzy logic controller is proposed to minimize the error between Tracking, Doppler Effect, Fuzzy Logic Controller I. INTRODUCTION Typically, radar sensors are comprised

Fan, Jeffrey

65

Connectivity in a UAV Multi-static Radar Network David W. Casbeer  

E-Print Network [OSTI]

Connectivity in a UAV Multi-static Radar Network David W. Casbeer and A. Lee Swindlehurst This paper describes a multi-static radar network composed of multiple unmanned air vehicles (UAVs). Time-delay and Doppler measurements taken by the UAV team are passed to a centralized processor to determine optimal

Swindlehurst, A. Lee

66

Rotational Doppler effect in x-ray photoionization  

SciTech Connect (OSTI)

The energy of the photoelectron experiences a red or blue Doppler shift when the molecule recedes from the detector or approaches him. This results in a broadening of the photoelectron line due to the translational thermal motion. However, the molecules also have rotational degrees of freedom and we show that the translational Doppler effect has its rotational counterpart. This rotational Doppler effect leads to an additional broadening of the spectral line of the same magnitude as the Doppler broadening caused by translational thermal motion. The rotational Doppler broadening as well as the rotational recoil broadening is sensitive to the molecular orbital from which the photoelectron is ejected. This broadening should be taken into account in analysis of x-ray photoemission spectra of super-high resolution and it can be directly observed using x-ray pump-probe spectroscopy.

Sun Yuping; Wang Chuankui [College of Physics and Electronics, Shandong Normal University, 250014 Jinan (China); Theoretical Chemistry, Roslagstullsbacken 15, Royal Institute of Technology, S-106 91 Stockholm (Sweden); Gel'mukhanov, Faris [Theoretical Chemistry, Roslagstullsbacken 15, Royal Institute of Technology, S-106 91 Stockholm (Sweden)

2010-11-15T23:59:59.000Z

67

Rotational Doppler effect in x-ray photoionization  

Science Journals Connector (OSTI)

The energy of the photoelectron experiences a red or blue Doppler shift when the molecule recedes from the detector or approaches him. This results in a broadening of the photoelectron line due to the translational thermal motion. However, the molecules also have rotational degrees of freedom and we show that the translational Doppler effect has its rotational counterpart. This rotational Doppler effect leads to an additional broadening of the spectral line of the same magnitude as the Doppler broadening caused by translational thermal motion. The rotational Doppler broadening as well as the rotational recoil broadening is sensitive to the molecular orbital from which the photoelectron is ejected. This broadening should be taken into account in analysis of x-ray photoemission spectra of super-high resolution and it can be directly observed using x-ray pump-probe spectroscopy.

Yu-Ping Sun; Chuan-Kui Wang; Faris Gel’mukhanov

2010-11-10T23:59:59.000Z

68

Selection of optimal AR spectral estimation method for internal carotid arterial Doppler signals using Cramer-Rao bound  

Science Journals Connector (OSTI)

In this study, Doppler signals recorded from internal carotid artery of 80 subjects were processed by PC-computer using autoregressive method and Doppler power spectra were obtained. The parameters of autoregressive method were estimated by different ... Keywords: AR spectral estimation method, Cramer-Rao bound, Doppler signal, Internal carotid artery, Power spectral density

Elif Derya íbeyli; ?nan Güler

2004-10-01T23:59:59.000Z

69

Title: Radar-observed convective characteristics during TWP-ICE  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Title: Radar-observed convective characteristics during TWP-ICE Title: Radar-observed convective characteristics during TWP-ICE Schumacher, Courtney Texas A&M University Houze, Robert University of Washington May, Peter Bureau or Meteorology Research Centre Frederick, Kaycee Cetrone, Jasmine Vallgren, Andreas Category: Field Campaigns This poster will describe the radar dataset obtained in the Tropical Warm Pool International Cloud Experiment (TWP-ICE), which is to take place 20 January - 14 February 2006 in the vicinity of Darwin, Australia. We will describe the convective systems observed during the project by two scanning C-band Doppler radars, one of which will provide dual-polarization measurements, and ARM's vertically pointing cloud radar and lidar installations. In addition, we will discuss the potential for combining

70

An Integrated Display and Analysis Methodology for Multivariable Radar Data BRENDA A. DOLAN AND STEVEN A. RUTLEDGE  

E-Print Network [OSTI]

products such as bulk hydrometeor identification and Doppler-derived winds to be viewed in real time-depth analysis using radar products, such as Doppler-derived wind vectors and hydrometeor identification, has identification, and rainfall rate. The software was successfully tested during the summers of 2004 and 2005

Rutledge, Steven

71

Equatorial electrojet irregularities investigations using a 50 MHz back-scatter radar and a digisonde at São Lu??s: some initial results  

Science Journals Connector (OSTI)

A new 50 MHz coherent back-scatter radar has recently become operational at the Equatorial Space Observatory of INPE at São Lu??s (2.33°S, 44.2°W, dip: ?0.5°), in Brazil, located close to the center of the equatorial electrojet. Preliminary results from a 12-day campaign in December 1999 involving this radar and a nearby digisonde are presented in this paper. The range–time–intensity (RTI) maps of electrojet irregularities show short-period (?5 min or larger) fluctuations and significant day-to-day variability. A notable characteristic is the midday descent in the altitude of the RTI pattern observed on some days when the dominant Doppler spectra are of type-2. This feature is similar to the diurnal variation of the base height of the q-type sporadic-E-layer (h?Es?q) simultaneously observed by the digisonde. Quasi-periodic fluctuations in the RTI and type-1 and type-2 spectral intensities seem to indicate electric field modulation from winds associated with typical gravity wave periods. Large surges in the westward irregularity drift velocity, presenting a higher velocity tail to the Doppler spectral distribution, is observed at sunset concurrent with the evening F-layer vertical uplift as observed by the digisonde. Some implications of these results on the E- and F-region electrodynamics are discussed.

M.A. Abdu; C.M. Denardini; J.H.A. Sobral; I.S. Batista; P. Muralikrishna; E.R. de Paula

2002-01-01T23:59:59.000Z

72

Radar-cross-section reduction of wind turbines. part 1.  

SciTech Connect (OSTI)

In recent years, increasing deployment of large wind-turbine farms has become an issue of growing concern for the radar community. The large radar cross section (RCS) presented by wind turbines interferes with radar operation, and the Doppler shift caused by blade rotation causes problems identifying and tracking moving targets. Each new wind-turbine farm installation must be carefully evaluated for potential disruption of radar operation for air defense, air traffic control, weather sensing, and other applications. Several approaches currently exist to minimize conflict between wind-turbine farms and radar installations, including procedural adjustments, radar upgrades, and proper choice of low-impact wind-farm sites, but each has problems with limited effectiveness or prohibitive cost. An alternative approach, heretofore not technically feasible, is to reduce the RCS of wind turbines to the extent that they can be installed near existing radar installations. This report summarizes efforts to reduce wind-turbine RCS, with a particular emphasis on the blades. The report begins with a survey of the wind-turbine RCS-reduction literature to establish a baseline for comparison. The following topics are then addressed: electromagnetic model development and validation, novel material development, integration into wind-turbine fabrication processes, integrated-absorber design, and wind-turbine RCS modeling. Related topics of interest, including alternative mitigation techniques (procedural, at-the-radar, etc.), an introduction to RCS and electromagnetic scattering, and RCS-reduction modeling techniques, can be found in a previous report.

Brock, Billy C.; Loui, Hung; McDonald, Jacob J.; Paquette, Joshua A.; Calkins, David A.; Miller, William K.; Allen, Steven E.; Clem, Paul Gilbert; Patitz, Ward E.

2012-03-05T23:59:59.000Z

73

Importance of Horizontally Inhomogeneous Environmental Initial Conditions to Ensemble Storm-Scale Radar Data Assimilation and Very Short-Range Forecasts  

Science Journals Connector (OSTI)

The assimilation of operational Doppler radar observations into convection-resolving numerical weather prediction models for very short-range forecasting represents a significant scientific and technological challenge. Numerical experiments over ...

David J. Stensrud; Jidong Gao

2010-04-01T23:59:59.000Z

74

A newsletter for non-scientists (and scientists) interested in MAGIC Radars transmit pulses of radio waves of a given frequency and receive signals that are  

E-Print Network [OSTI]

and the speed of propagation of radio waves, which is the speed of light. To understand why the Doppler effect by the distance to the object and the speed of light. As all oscillations travel the same distance and at the same of the Doppler effect in everyday life is the radar gun, whether used for measuring the speed of baseballs

75

Radar | Open Energy Information  

Open Energy Info (EERE)

Radar Radar Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Radar Details Activities (0) Areas (0) Regions (0) NEPA(0) Exploration Technique Information Exploration Group: Remote Sensing Techniques Exploration Sub Group: Active Sensors Parent Exploration Technique: Active Sensors Information Provided by Technique Lithology: Stratigraphic/Structural: Detect fault and ground movement Hydrological: Can give indications about subsurface geothermal fluid flow Thermal: Dictionary.png Radar: Radar is an active-sensor remote sensing tool used to detect small changes in ground movement at geothermal locations. Other definitions:Wikipedia Reegle Introduction RAdio Detection And Ranging (RADAR) is used in a wide variety of applications. In remote sensing applications, the source of the radio waves

76

Wideband Waveform Design principles for Solid-state Weather Radars  

SciTech Connect (OSTI)

The use of solid-state transmitter is becoming a key part of the strategy to realize a network of low cost electronically steered radars. However, solid-state transmitters have low peak powers and this necessitates the use of pulse compression waveforms. In this paper a frequency diversity wideband waveforms design is proposed to mitigate low sensitivity of solid-state transmitters. In addition, the waveforms mitigate the range eclipsing problem associated with long pulse compression. An analysis of the performance of pulse compression using mismatched compression filters designed to minimize side lobe levels is presented. The impact of range side lobe level on the retrieval of Doppler moments are presented. Realistic simulations are performed based on CSU-CHILL radar data and Center for Collaborative Adaptive Sensing of the Atmosphere (CASA) Integrated Project I (IP1) radar data.

Bharadwaj, Nitin; Chandrasekar, V.

2012-01-01T23:59:59.000Z

77

ARM - Radar Backgrounder  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

News Field Notes Blog feed Events feed Employment Research Highlights Data Announcements Education News Archive What's this? Social Media Guidance Radar Backgrounder ARM Scanning...

78

The Doppler Effect in the Canal Rays in Neon  

Science Journals Connector (OSTI)

The neon spectrum in the ultraviolet between 2500A and 4000A from a canal-ray tube was examined for Doppler effects. Potentials up to 24,000 volts were applied to excite the discharge. Doppler effects were found to be present among the stronger lines in the first and second spark spectra of neon and, with only two exceptions, were absent from the arc spectrum lines. About fifty strong and faint lines showing Doppler effects were observed. The canal-ray stream consists of rapidly moving neon atoms which radiate only when in the ionized state. Neon behaves similarly to argon at high voltages and differs from most gases in that the radiation from the canal rays is almost entirely from atoms in the ionized state.

W. Romig

1931-11-01T23:59:59.000Z

79

Bistatic occlusion effect of missile warhead based on micro-Doppler effect  

Science Journals Connector (OSTI)

Abstract Micro-Doppler effect is induced by the micro-motion dynamics of the radar target itself or any structure on the target. Spinning, coning and wobble are typical basic micro-motions of missile warhead. In this paper, a cone-shaped model for missile warhead with micro-nutation is established under the case of bistatic radar system, followed by the theoretical formula of bistatic micro-nutation is derived. Using the method of short-time Fourier transform, which confirms the simulated results are identical to the theoretical results. In addition, in order to further approach the actual environment. Base on micro-Doppler effect, the effective scattering center model with occlusion effect is considered under the case of bistatic radar system. The simulated results are compared with the fixed scattering point model without the occlusion effect. By the simulation studies, it shows the otherness between the actual environment and ideal assumption. A certain of theoretical analysis conclusions for extracting the features of missile warhead in bistatic radar system are gained, which can be applied to radar target recognition in the future work.

Ming Li; Yuesong Jiang

2014-01-01T23:59:59.000Z

80

X-band Radar System for Detecting Heart and Respiration Rates  

E-Print Network [OSTI]

the sensing system is easy to handle, even ordinary person who is not instructed about usage sense. In a dielectric material, circularly polarized waves are reflected back, changing the axial ratio with the distance between antenna and target. Figure 1. The block diagram of CW Doppler radar system

Park, Seong-Ook

Note: This page contains sample records for the topic "radar doppler spectra" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Submesoscale Coastal Ocean Flows Detected By Very High Frequency Radar and Autonomous Underwater Vehicles  

E-Print Network [OSTI]

Submesoscale Coastal Ocean Flows Detected By Very High Frequency Radar and Autonomous Underwater, autonomous underwater vehicles (AUV), equipped with upward and downward- looking 1.2 MHz Acoustic Doppler and seven snapshots were subsequently time-averaged to form a mean profile from each experiment. In the down-wind

Shay, Lynn K. "Nick"

82

Sandia National Laboratories: Radar Friendly Blades  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

MitigationRadar Friendly Blades Radar Friendly Blades Some wind farms have the potential to cause interference with the normal operation of radar systems used for security, weather...

83

Our Old Friend the Doppler Effect  

Science Journals Connector (OSTI)

You’dbe hardput these days topickupany bookonastronomy and notfindsomewhere in its pages mention of the Doppler effect; this might be to dowith the proper ... of coursewe knownowthat this actually isn’t aDoppler

Keith Robinson

2007-01-01T23:59:59.000Z

84

Doppler Effect in a Moving Medium  

Science Journals Connector (OSTI)

The great increase in the accuracy of Doppler measurements in space requires a rigorous definition ... perturbation theorem which generalizes the concept of the Doppler effect as a Lagrangean derivative. Relativi...

Bruno Bertotti

1998-02-01T23:59:59.000Z

85

Echocardiography Signal Modeling Considering Doppler Effect  

Science Journals Connector (OSTI)

A new model for the simulation of Blood Flow signal is introduced. Doppler ultrasound scanning is an important technique that ... -invasively evaluates blood flow. A method for Doppler simulation that previously ...

Hamed Rakhshan; H. Behnam PhD

2008-01-01T23:59:59.000Z

86

"DERIVATION" OF THE DE BROGLIE RELATION FROM THE DOPPLER EFFECT  

E-Print Network [OSTI]

BROGLIE RELATION FROM THE DOPPLER EFFECT Frank S. Crawfordusual derivation of the Doppler effect gives Eq. (l). (The

Crawford, Frank S.

2013-01-01T23:59:59.000Z

87

ARM - Measurement - Radar polarization  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

polarization polarization ARM Data Discovery Browse Data Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Measurement : Radar polarization The temporal and geometric behavior of the electric field vector of an electromagnetic wave transmitted or received by a radar system, e.g. elliptical polarization, differential reflectivity, phase shift, co-polar correlation coefficient, linear depolarization ratio. Categories Cloud Properties Instruments The above measurement is considered scientifically relevant for the following instruments. Refer to the datastream (netcdf) file headers of each instrument for a list of all available measurements, including those recorded for diagnostic or quality assurance purposes. ARM Instruments CSAPR : C-Band ARM Precipitation Radar

88

Activated Fluorescence and Doppler Effect  

Science Journals Connector (OSTI)

... I have tried to observe the speed acquired by the atoms as a L)oppler effect, and I give here a preliminary account of the results, which agree also quantitatively ... the intensity in the broadened line is quite different from that due to the ordinary Doppler ...

FRANCO RASETTI

1926-07-10T23:59:59.000Z

89

Definition: Radar | Open Energy Information  

Open Energy Info (EERE)

Radar Radar Jump to: navigation, search Dictionary.png Radar Radar is an active-sensor remote sensing tool used to detect small changes in ground movement at geothermal locations. View on Wikipedia Wikipedia Definition Radar is an object detection system which uses radio waves to determine the range, altitude, direction, or speed of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. The radar dish or antenna transmits pulses of radio waves or microwaves which bounce off any object in their path. The object returns a tiny part of the wave's energy to a dish or antenna which is usually located at the same site as the transmitter. Radar was secretly developed by several nations before and

90

Laser- and Radar-based Mission Concepts for Suborbital and Spaceborne Monitoring of Seismic Surface Waves  

SciTech Connect (OSTI)

The development of a suborbital or spaceborne system to monitor seismic waves poses an intriguing prospect for advancing the state of seismology. This capability would enable an unprecedented global mapping of the velocity structure of the earth's crust, understanding of earthquake rupture dynamics and wave propagation effects, and event source location, characterization and discrimination that are critical for both fundamental earthquake research and nuclear non-proliferation applications. As part of an ongoing collaboration between LLNL and JPL, an advanced mission concept study assessed architectural considerations and operational and data delivery requirements, extending two prior studies by each organization--a radar-based satellite system (JPL) for earthquake hazard assessment and a feasibility study of space- or UAV-based laser seismometer systems (LLNL) for seismic event monitoring. Seismic wave measurement requirements include lower bounds on detectability of specific seismic sources of interest and wave amplitude accuracy for different levels of analysis, such as source characterization, discrimination and tomography, with a 100 {micro}m wave amplitude resolution for waves nominally traveling 5 km/s, an upper frequency bound based on explosion and earthquake surface displacement spectra, and minimum horizontal resolution (1-5 km) and areal coverage, in general and for targeted observations. For a radar system, corresponding engineering and operational factors include: Radar frequency (dictated by required wave amplitude measurement accuracy and maximizing ranging, Doppler or interferometric sensitivity), time sampling (maximum seismic wave frequency and velocity), and overall system considerations such as mass, power and data rate. Technical challenges include characterization of, and compensation for, phase distortion resulting from atmospheric and ionospheric perturbations and turbulence, and effects of ground scattering characteristics and seismic ground motion on phase coherence over interferometric time intervals. Since the temporal sampling requirement may be finer than that possible for a high-altitude sensor to traverse a synthetic aperture length, a geostationary, real-aperture Ka-band system or constellation for equatorial and moderate-latitude global coverage is one option considered. The short wavelength would maximize interferometric sensitivity to small surface displacements and minimize required antenna area. Engineering issues include the design and deployment of a large ({approx} 100m) fixed aperture antenna; and fast electronic beam steering (entire aperture within nominal 1 s interferometric interval) with high-efficiency integrated transmit/receive modules. For a suborbital system, platform instability is an issue whereas at high earth orbit signal-to-noise and attendant power requirements dominate. Data delivery requirements include large-volume data storage and transmission; development of real-time, on-board event detection and processing algorithms, and data management structures for these very large data sets. A far-term roadmap would comprise a proof-of-concept demonstration using a laser or radar system mounted on a stratospheric balloon or UAV to image seismic wavefields from planned events (e.g. large mine blasts and/or purpose-designed explosions) and earthquake targets of opportunity. The technological challenges to developing any such seismic monitoring system, whether laser- or radar-based, are at this stage enormous. However, these concept studies suggest the long-term feasibility of such a system and drive the development of enabling technologies while fostering collaboration on meeting scientific and operational challenges of agencies such as NASA, DOE and DoD.

Foxall, W; Schultz, C A; Tralli, D M

2004-09-21T23:59:59.000Z

91

Radar MeteorologyRadar Meteorology Feb 20, 1941 10 cm (S-band) radar used to track rain showers (Ligda)  

E-Print Network [OSTI]

10-14 W T/R switch antenna #12;Radar SystemRadar System Transmitter--produces high power pulses similar observations in the early 1940's (U.S. Air Corps meteorologists receiving "radar" training at MIT in 1943 First operational weather radar, Panama, 1943 Science of radar meteorology born from WWII research

Rutledge, Steven

92

Doppler effect in Schwarzschild geometry  

E-Print Network [OSTI]

The Doppler shift considered in general relativity involves mixed contributions of distinct, gravitational and kinematical origins and for most metrics or trajectories it takes a complex form. The expression for the Doppler shift may simplify due to particular symmetries. In Schwarzschild spacetime it factorizes in the case of radial fall for an observer and radial null geodesic. The resulting expression is composed of factors that can be identified with contributions arising from classical, special relativistic and general relativistic origins. This result turns out to be more general: it holds for the whole class of observers travelling parallel to the spatial path of null geodesics when receiving the signal. It also holds for a particular type of in-fall in the case of a Kerr metric.

A. Radosz; A. T. Augousti; K. Ostasiewicz

2007-12-13T23:59:59.000Z

93

The São Paulo Weather Radar Network Program  

Science Journals Connector (OSTI)

A radar network to cover the State of São Paulo, Brazil, was in consideration since the pioneer efforts in radar meteorology in the country were developed in the middle 70’s with the operation of a radar at Ba...

R. V. Calheiros

1990-01-01T23:59:59.000Z

94

The Operational Weather Radar Network in Europe  

Science Journals Connector (OSTI)

The operational weather radar network in Europe covers more than 30 countries and contains more than 200 weather radars. The radar network is heterogeneous in hardware, signal processing, transmit/receive frequency, and scanning strategy, thus making it ...

Asko Huuskonen; Elena Saltikoff; Iwan Holleman

2014-06-01T23:59:59.000Z

95

Performance degradation of OFDM systems due to Doppler spreading  

E-Print Network [OSTI]

on Jakes’ model for the Doppler effects, and an exponentialand S. Kaiser, “The effects of Doppler spreads in OFDM (A)In particular, the effect of Doppler spreading destroys the

Wang, T J; Proakis, J G; Masry, E; Zeidler, James R

2006-01-01T23:59:59.000Z

96

Doppler Effect in Light-Scattering  

Science Journals Connector (OSTI)

... the subject classically, the result to be expected is obvious: there should be a Doppler broadening of the incident spectral line, varying with the angle of observation, and determined ... should persist in the scattered light in the same position with no change except a Doppler broadening.

C. V. RAMAN

1931-10-10T23:59:59.000Z

97

Doppler Effect of Nuclear Resonance Level  

Science Journals Connector (OSTI)

... cent. It has been pointed out by Frisch5 that these widths are comparable with the Doppler width which such resonance must show in consequence of the thermal agitation of the capturing ... of the thermal agitation of the capturing nuclei. According to Bethe and Placzek3, the Doppler width is Er being the resonance energy and M the mass of the nucleus. ...

HANS VON HALBAN; HUGH PAXTON

1938-01-15T23:59:59.000Z

98

Fish embryo multimodal imaging by laser Doppler digital holography  

Science Journals Connector (OSTI)

A laser Doppler imaging scheme combined to an upright microscope is proposed. Quantitative Doppler imaging in both velocity norm and direction, as well as amplitude contrast of either...

Gross, Michel; Verrier, Nicolas; Picart, Pascal

99

The complex Doppler effect in double negative media  

Science Journals Connector (OSTI)

The Doppler effect in doubly double negative acoustic media is ... ’s functions. It is shown that several Doppler modes can be generated by a monochromatic...

I. V. Lisenkov; S. A. Nikitov

2011-06-01T23:59:59.000Z

100

Development of the doppler electron velocimeter: theory.  

SciTech Connect (OSTI)

Measurement of dynamic events at the nano-scale is currently impossible. This paper presents the theoretical underpinnings of a method for making these measurements using electron microscopes. Building on the work of Moellenstedt and Lichte who demonstrated Doppler shifting of an electron beam with a moving electron mirror, further work is proposed to perfect and utilize this concept in dynamic measurements. Specifically, using the concept of ''fringe-counting'' with the current principles of transmission electron holography, an extension of these methods to dynamic measurements is proposed. A presentation of the theory of Doppler electron wave shifting is given, starting from the development of the de Broglie wave, up through the equations describing interference effects and Doppler shifting in electron waves. A mathematical demonstration that Doppler shifting is identical to the conceptually easier to understand idea of counting moving fringes is given by analogy to optical interferometry. Finally, potential developmental experiments and uses of a Doppler electron microscope are discussed.

Reu, Phillip L.

2007-03-01T23:59:59.000Z

Note: This page contains sample records for the topic "radar doppler spectra" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Effect of Doppler broadening on Autler-Townes splitting in the molecular cascade excitation scheme  

Science Journals Connector (OSTI)

Theoretical analysis of the Autler-Townes splitting pattern in a three-level cascade excitation of a Doppler-broadened sample reveals that the observed Autler-Townes splitting is not only a function of the coupling-laser Rabi frequency, as in the homogeneously broadened case, but can also strongly depend on the wavenumber ratio of the coupling and probe lasers. Utilizing a steady-state density matrix formalism, we derive exact expressions for the populations of the intermediate and upper levels for a homogeneously broadened system. In the limit of a weak probe field, analytical expressions for Doppler-broadened excitation spectra from the intermediate and upper levels are derived. Using these expressions, we investigate the critical role of Doppler broadening on the observation of Autler-Townes splitting and its asymptotic behavior as a function of the coupling Rabi frequency for counterpropagating and copropagating configurations for different wavenumber ratios of the lasers.

E. Ahmed and A. M. Lyyra

2007-11-09T23:59:59.000Z

102

Radar Measurement of the Upper Atmosphere  

Science Journals Connector (OSTI)

...of the Upper Atmosphere James C. G...two decades large radars have...of the upper atmosphere. These radars...ionospheric plasma, all as functions...ionospheric plasma by detection...is wasted. Atmospheric radar scientists...305 m and an area of 73,000...frequency of 430 MHz. The radar...

James C. G. Walker

1979-10-12T23:59:59.000Z

103

Simultaneous radar and lidar cloud measurements at Geesthacht (53.5°N, 10.5°E)  

Science Journals Connector (OSTI)

Comparisons have been made of the cloud profiles obtained from the backscatter signals of a 95-GHz radar and a 720-nm lidar system between 23 May and 4 November 1997 at Geesthacht (53°24? N, 10°26? E). Although the wavelengths of the two systems differ by a factor of 4 000, remarkably similar data have been obtained in many cases. There are differences, though. Small droplets do not interact significantly with the radar pulses, and hence can only be seen by the lidar due to their strong scattering in the UV/VIS. On the other hand, attenuation of the lidar pulses by underlying clouds and gas absorbers makes upper cloud regions and especially cloud top heights better detectable for the radar. Rain and snow falling out of a cloud and evaporating on the way down cannot be distinguished from the cloud region by the radar, but a fast downward component in the Doppler spectrum is indicative of precipitation in or under a cloud. For quantitative cloud studies collocated radar-lidar systems considerably add to the experimental capabilities of each of the two systems alone.

C. Weitkamp; H. Flint; W. Lahmann; F.A. Theopold; O. Danne; M. Quante; E. Raschke

1999-01-01T23:59:59.000Z

104

E-Print Network 3.0 - arm mixed-phase arctic Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

for ice and ... Source: Collection: Environmental Sciences and Ecology 95 Detection of supercooled liquid in mixedphase clouds using radar Doppler spectra Summary:...

105

Slide 1  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Vertical Air Velocity and Precipitation Parameter Retrievals in Rainfall from 95-GHz Doppler Radar Spectra Edward P Luke 1 , Scott E Giangrande 2 , and Pavlos Kollias 2 1....

106

ARM - Data Announcements Article  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

neutral interface for comparison in fine detail of high-resolution large eddy simulation model output with representative observations through radar Doppler spectra forward...

107

Reversed Doppler effect under reflection from a shock electromagnetic wave  

Science Journals Connector (OSTI)

The possibility of observing the reversed Doppler effect in an electrodynamic system of coupled transmission...

A. M. Belyantsev; A. B. Kozyrev

2002-11-01T23:59:59.000Z

108

Comparison and analysis of Envisat ASAR ocean wave spectra with buoy data in the northern Pacific Ocean  

Science Journals Connector (OSTI)

The validation and assessment of Envisat advanced synthetic aperture radar (ASAR) ocean wave spectra products are important to their application in ocean wave numerical predictions. Six-year ASAR wave ... co-loca...

Qifeng Ren ???; Jie Zhang ??…

2011-01-01T23:59:59.000Z

109

Doppler-Broadened Spectral Emission from the Turbulently Heated Plasma of Burnout V  

Science Journals Connector (OSTI)

In an efficient ion heating mode recently discovered in the Burnout-V turbulent-heating experiment, the line profiles of emission spectra exhibit three noteworthy features: (1) a marked Doppler broadening (full width at half-maximum ?10 Å) of the Balmer lines, (2) a "red"/"blue" asymmetry dependent on the geometry of the plasma container, and (3) non-Gaussian line shapes near the central wavelengths.

I. Alexeff; G. E. Guest; J. R. McNally; Jr.; R. V. Neidigh; F. R. Scott

1969-08-11T23:59:59.000Z

110

Doppler Imaging of Exoplanets and Brown Dwarfs  

E-Print Network [OSTI]

Doppler Imaging produces 2D global maps of rotating objects using high-dispersion spectroscopy. When applied to brown dwarfs and extrasolar planets, this technique can constrain global atmospheric dynamics and/or magnetic effects on these objects in un- precedented detail. I present the first quantitative assessment of the prospects for Doppler Imaging of substellar objects with current facilities and with future giant ground-based telescopes. Observations will have the greatest sensitivity in K band, but the H and L bands will also be useful for these purposes. To assess the number and availability of targets, I also present a compilation of all measurements of photometric variability, rotation period (P), and projected rotational velocity (v sin i) for brown dwarfs and exoplanets. Several bright objects are already accessible to Doppler Imaging with currently available instruments. With the development of giant ground-based telescopes, Doppler Imaging will become feasible for many dozens of brown dwarfs and...

Crossfield, Ian J M

2014-01-01T23:59:59.000Z

111

915-MHz Radar Wind Profiler (915RWP) Handbook  

SciTech Connect (OSTI)

The 915 MHz radar wind profiler/radio acoustic sounding system (RWP/RASS) measures wind profiles and backscattered signal strength between (nominally) 0.1 km and 5 km and virtual temperature profiles between 0.1 km and 2.5 km. It operates by transmitting electromagnetic energy into the atmosphere and measuring the strength and frequency of backscattered energy. Virtual temperatures are recovered by transmitting an acoustic signal vertically and measuring the electromagnetic energy scattered from the acoustic wavefront. Because the propagation speed of the acoustic wave is proportional to the square root of the virtual temperature of the air, the virtual temperature can be recovered by measuring the Doppler shift of the scattered electromagnetic wave.

Coulter, R

2005-01-01T23:59:59.000Z

112

Anomalous Doppler effects in phononic band gaps  

Science Journals Connector (OSTI)

Doppler effects in periodic acoustic media were studied theoretically and experimentally. Analytical formulas are derived using the Green’s function formalism. We found that a far field observer cannot hear the sound inside a band gap from a stationary source, but a moving source can be heard even if the frequency is inside the gap, and the Doppler shifts can be inverted or anomalously large.

Xinhua Hu; Zhihong Hang; Jensen Li; Jian Zi; C. T. Chan

2006-01-30T23:59:59.000Z

113

Reversed Doppler effect in double negative metamaterials  

Science Journals Connector (OSTI)

Doppler shifts in double negative metamaterials have never been observed. This Rapid Communication presents experimental results on Doppler effect in a double negative acoustic metamaterial. We observed that frequency was downshifted when the source was approaching and upshifted when receding. Notably, while in ordinary media wavelengths corresponding to downshifted frequencies are longer, we demonstrate that in double negative metamaterials wavelengths increase as the frequencies increase. Consequently even though the frequencies were downshifted in front of the moving source, the wavelengths became shorter.

Sam Hyeon Lee; Choon Mahn Park; Yong Mun Seo; Chul Koo Kim

2010-06-14T23:59:59.000Z

114

High resolution ion Doppler spectroscopy at Prairie View Rotamak  

SciTech Connect (OSTI)

A fast ion Doppler spectroscopy (IDS) diagnostic system is installed on the Prairie View Rotamak to measure ion temperature and plasma flow. The diagnostic employs a single channel photomultiplier tube and a Jarrell-Ash 50 monochromator with a diffraction grating line density of 1180 lines/mm, which allows for first order spectra of 200-600 nm. The motorized gear of the monochromator allows spectral resolution of 0.01 nm. Equal IDS measurements are observed for various impurity emission lines of which carbon lines exhibit stronger intensities. Furthermore, the diagnostics is examined in an experiment where plasma experiences sudden disruption and quick recovery. In this case, the IDS measurements show {approx}130% increase in ion temperature. Flow measurements are shown to be consistent with plasma rotation.

Houshmandyar, Saeid; Yang Xiaokang [Solar Observatory Department, Prairie View A and M University, Prairie View, Texas 77446 (United States); Magee, Richard [Department of Physics, West Virginia University, Morgantown, West Virginia 26506 (United States)

2012-10-15T23:59:59.000Z

115

Sub-Doppler resonances in the back-scattered light from random porous media infused with Rb vapor  

E-Print Network [OSTI]

We report on the observation of sub-Doppler resonances on the back-scattered light from a random porous glass medium with rubidium vapor filling its interstices. The sub-Doppler spectral lines are the consequence of saturated absorption where the incident laser beam saturates the atomic medium and the back-scattered light probes it. Some specificities of the observed spectra reflect the transient atomic evolution under confinement inside the pores. Simplicity, robustness and potential miniaturization are appealing features of this system as a spectroscopic reference.

Villalba, S; Lenci, L; Bloch, D; Lezama, A; Failache, H

2013-01-01T23:59:59.000Z

116

Definition: Synthetic Aperture Radar | Open Energy Information  

Open Energy Info (EERE)

Aperture Radar Aperture Radar Jump to: navigation, search Dictionary.png Synthetic Aperture Radar Synthetic-aperture radar (SAR) is an active microwave remote sensing technology that measures the phase difference between a radar wave emitted from an antennae attached to a satellite or aircraft to generate high-resolution images of a surface.[1] View on Wikipedia Wikipedia Definition Also Known As SAR Related Terms radar References ↑ Synthetic Aperature Radar: Systems and Signal Processing (Curlander and McDonough - 1991 - book) fue LikeLike UnlikeLike You like this.Sign Up to see what your friends like. l cell, Retrieved from "http://en.openei.org/w/index.php?title=Definition:Synthetic_Aperture_Radar&oldid=493069" Category: Definitions What links here Related changes

117

Definition: Interferometric Synthetic Aperture Radar | Open Energy  

Open Energy Info (EERE)

Interferometric Synthetic Aperture Radar Interferometric Synthetic Aperture Radar Jump to: navigation, search Dictionary.png Interferometric Synthetic Aperture Radar Interferometric Synthetic Aperture Radar (InSAR) utilizes SAR images from two different time periods to generate maps of surface deformation. The technique can potentially measure millimeter-scale changes in the Earth's surface.[1][2] View on Wikipedia Wikipedia Definition Also Known As InSAR, IfSAR Related Terms Synthetic Aperture Radar, radar, sustainability References ↑ Synthetic Aperture Radar Interferometry to Measure Earth's Surface Topography and Its Deformation (Burgmann et al. 2000) ↑ Improved Visulaization of Satellite Radar InSAR Observed Structural Controls at Producing Geothermal Field Using Modeled Horizontal Surface Displacements(Opplinger et al. 2006)

118

Obstacle penetrating dynamic radar imaging system  

DOE Patents [OSTI]

An obstacle penetrating dynamic radar imaging system for the detection, tracking, and imaging of an individual, animal, or object comprising a multiplicity of low power ultra wideband radar units that produce a set of return radar signals from the individual, animal, or object, and a processing system for said set of return radar signals for detection, tracking, and imaging of the individual, animal, or object. The system provides a radar video system for detecting and tracking an individual, animal, or object by producing a set of return radar signals from the individual, animal, or object with a multiplicity of low power ultra wideband radar units, and processing said set of return radar signals for detecting and tracking of the individual, animal, or object.

Romero, Carlos E. (Livermore, CA); Zumstein, James E. (Livermore, CA); Chang, John T. (Danville, CA); Leach, Jr.. Richard R. (Castro Valley, CA)

2006-12-12T23:59:59.000Z

119

Category:Radar | Open Energy Information  

Open Energy Info (EERE)

of 6 total. I InSAR P PSInSAR R Radar S SAR SqueeSAR SRT Retrieved from "http:en.openei.orgwindex.php?titleCategory:Radar&oldid689849" Categories: Geothermal Active Sensors...

120

C-Band Scanning ARM Precipitation Radar (C-SAPR) Handbook  

SciTech Connect (OSTI)

The C-band scanning ARM precipitation radar (C-SAPR) is a scanning polarimetric Doppler radar transmitting simultaneously in both H and V polarizations. With a 350-kW magnetron transmitter, this puts 125 kW of transmitted power for each polarization. The receiver for the C-SAPR is a National Center for Atmospheric Research (NCAR) -developed Hi-Q system operating in a coherent-on-receive mode. The ARM Climate Research Facility operates two C-SAPRs; one of them is deployed near the Southern Great Plains (SGP) Central Facility near the triangular array of X-SAPRs, and the second C-SAPR is deployed at ARM’s Tropical Western Pacific (TWP) site on Manus Island in Papua New Guinea.

Widener, K; Bharadwaj, N

2012-11-13T23:59:59.000Z

Note: This page contains sample records for the topic "radar doppler spectra" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Designing a Multichannel Sense-and-Avoid Radar for Small UASs  

E-Print Network [OSTI]

, then the transmitted signal’s bandwidth will be 15 MHz and not 500 kHz. Pulse compression is also used in FMCW radars (as its name implies) because the bandwidth of the transmit signal doesn’t correspond to the SRP (i.e., the duration of each pulse... also determine what the bandwidth and SRP of the signal are. Equation 1.12 shows how the Doppler shift can be calculated based on radial velocity, and the signal’s wavelength ( ). (1.11) (1...

Zakharov, Mikhail

2014-05-31T23:59:59.000Z

122

WAVE-DRIVEN SURFACE FROM HF RADAR  

E-Print Network [OSTI]

experiments using the University of Miami's Ocean Surface Current Radar (OSCR) (Shay et al., 1995, 1997 to the internal wave signals. Observations The HF radar system mapped the coastal ocean currents over a 30 Ã? 45 kmFEATURE INTERNAL CURRENTS WAVE-DRIVEN SURFACE FROM HF RADAR By Lynn K. Shay Observations from

Miami, University of

123

Scanning ARM Cloud Radars Part II: Data Quality Control and Processing  

SciTech Connect (OSTI)

The Scanning ARM Cloud Radars (SACR’s) are the primary instruments for documenting the four-dimensional structure and evolution of clouds within a 20-30 km radius from the ARM fixed and mobile sites. Here, the post-processing of the calibrated SACR measurements is discussed. First, a feature mask algorithm that objectively determines the presence of significant radar returns is described. The feature mask algorithm is based on the statistical properties of radar receiver noise. It accounts for atmospheric emission and is applicable even for SACR profiles with few or no signal-free range gates. Using the nearest-in-time atmospheric sounding, the SACR radar reflectivities are corrected for gaseous attenuation (water vapor and oxygen) using a line-by-line absorption model. Despite having a high pulse repetition frequency, the SACR has a narrow Nyquist velocity limit and thus Doppler velocity folding is commonly observed. An unfolding algorithm that makes use of a first guess for the true Doppler velocity using horizontal wind measurements from the nearest sounding is described. The retrieval of the horizontal wind profile from the Hemispherical Sky – Range Height Indicator SACR scan observations and/or nearest sounding is described. The retrieved horizontal wind profile can be used to adaptively configure SACR scan strategies that depend on wind direction. Several remaining challenges are discussed, including the removal of insect and second-trip echoes. The described algorithms significantly enhance SACR data quality and constitute an important step towards the utilization of SACR measurements for cloud research.

Kollias, Pavlos; Jo, Ieng; Borque, Paloma; Tatarevic, Aleksandra; Lamer, Katia; Bharadwaj, Nitin; Widener, Kevin B.; Johnson, Karen; Clothiaux, Eugene E.

2014-03-01T23:59:59.000Z

124

Digital Doppler radial velocity data compared objectively with digital reflectivity radar data  

E-Print Network [OSTI]

I N 4 N CLI ILI IL O J ILI 6 0 ) Id CC OE IC + ILI IC I Vl ?T T W 0 0 0 LLI 0 Z 4( W 3 C- 7: LLI ri 4 4 I I N 0' 0 \\L III gQ ~ 4 N NZ WO 8 I 4l zj WN ~4I III W I- g I 0 R 0 O. I 0 0 ~ N 0 0 LI 0 0... ( ? ') max PRF (4) for c equal to the speed of propagation of electromagnetic radia- tion (c = 2. 998 x 10 m s ). 8 -1 By substituting (4) into (3), we express the maximum unambiguous radial velocity as a function of maximum range, v max 8 rmax (5...

Beaver, Thomas Foster

2012-06-07T23:59:59.000Z

125

ATMOSPHERIC PHYSICS AS OBSERVED BY A VERTICALLY POINTING DOPPLER RADAR Frdric Fabry, and Isztar Zawadzki  

E-Print Network [OSTI]

and precipitation physics and small scale dynamics. We find that many of these images would make wonderful textbook resolution the reflectivity patterns of precipitation (Fabry et al. 1992), the VPR has been upgraded

Fabry, Frederic

126

The use of Doppler radar to predict cloud-to-ground lightning  

E-Print Network [OSTI]

If the National Weather Service could forecast the occurrences of cloud-toground lightning strikes, it would benefit the authorities that are served by the WSR-88Ds. In this thesis I will examine the WSR-88D level 11 archive data from Houston, Texas...

Aclin, Keith Andrew

2012-06-07T23:59:59.000Z

127

Observations of a tornadic supercell over Oxfordshire using a pair of Doppler radars  

E-Print Network [OSTI]

). The strong winds associated with this tornado led to damage of trees, roofs and streetlights. Damage site a valuable means to study the structure of the storm which produced it. Surface observations and analysis

Reading, University of

128

Reversed Doppler Effect in Photonic Crystals  

Science Journals Connector (OSTI)

Nonrelativistic reversed Doppler shifts have never been observed in nature and have only been speculated to occur in pathological systems with simultaneously negative effective permittivity and permeability. This Letter presents a different, new physical phenomenon that leads to a nonrelativistic reversed Doppler shift in light. It arises when light is reflected from a moving shock wave propagating through a photonic crystal. In addition to reflection of a single frequency, multiple discrete reflected frequencies or a 10 GHz periodic modulation can also be observed when a single carrier frequency of wavelength 1????m is incident.

Evan J. Reed; Marin Solja?i?; John D. Joannopoulos

2003-09-23T23:59:59.000Z

129

Raindrop size distributions and associated effective radar reflectivity comparisons /  

E-Print Network [OSTI]

-0. 629869Z6 19. 38 - 8. 59 6. 40 5. o3 0. 0001 0. 0001 0. 0001 0. 0001 F VALUE 184. 66 PR& F 0. 0001 STD DEV 0. 58555116 R-SQUARE 0. 527609 C. V. 41. 2185 LI'ISUBI MEAN 1. 42060192 DF 1 1 1 TYPE IV SS F VALUE 25. 27055111 73... for the detection of severe weather phenomena such as tornadoes, hailstorms, and severe thunderstomns. In addition to storm applications, radar observations, concurrent with di sdrometer determi- nations of raindrop spectra, are important data for cloud physics...

Gosdin, Malcolm Elwood

1982-01-01T23:59:59.000Z

130

Fish embryo multimodal imaging by laser Doppler digital holography  

E-Print Network [OSTI]

A laser Doppler imaging scheme combined to an upright microscope is proposed. Quantitative Doppler imaging in both velocity norm and direction, as well as amplitude contrast of either zebrafish flesh or vasculature is demonstrated.

Verrier, Nicolas; Picart, Pascal; Gross, Michel

2015-01-01T23:59:59.000Z

131

The doppler effect in light scattered by liquds  

Science Journals Connector (OSTI)

The influence of temperature on the nature of the Doppler effect in light scattered by liquids has been ... of carbon tetrachloride at 70°C. the Doppler components become fainter and broader merging with ... At t...

B. V. Raghavendra Rao

1935-05-01T23:59:59.000Z

132

Doppler effect of subluminal and superluminal sources in eight dimensions  

Science Journals Connector (OSTI)

The study of the relativistic Doppler effect of subluminal and superluminal sources has been ... space. It has been shown that correct Doppler shifts are obtained in the external spaces ... of these sources and t...

H. C. Chandola; B. S. Rajptut

1984-01-30T23:59:59.000Z

133

Photoacoustic Doppler Effect from Flowing Small Light-Absorbing Particles  

Science Journals Connector (OSTI)

From the flow of a suspension of micrometer-scale carbon particles, the photoacoustic Doppler shift is observed. As predicted theoretically, the observed Doppler shift equals half of that in Doppler ultrasound and does not depend on the direction of laser illumination. This new physical phenomenon provides a basis for developing photoacoustic Doppler flowmetry, which can potentially be used for detecting fluid flow in optically scattering media and especially low-speed blood flow of relatively deep microcirculation in biological tissue.

Hui Fang; Konstantin Maslov; Lihong V. Wang

2007-10-29T23:59:59.000Z

134

The possibility of superluminal sources and their Doppler effect  

Science Journals Connector (OSTI)

The ‘Extended Theory of Relativity’ allows in particular extending the Doppler effect formulae to Superluminal sources. This point is...

R. Mignani; E. Recami

1974-10-01T23:59:59.000Z

135

Spectroscopic observation of the rotational Doppler effect  

E-Print Network [OSTI]

We report on the first spectroscopic observation of the rotational Doppler shift associated with light beams carrying orbital angular momentum. The effect is evidenced as the broadening of a Hanle/EIT coherence resonance on Rb vapor when the two incident Laguerre-Gaussian laser beams have opposite topological charges. The observations closely agree with theoretical predictions.

S. Barreiro; J. W. R. Tabosa; H. Failache; A. Lezama

2006-07-26T23:59:59.000Z

136

Spectroscopic Observation of the Rotational Doppler Effect  

Science Journals Connector (OSTI)

We report on the first spectroscopic observation of the rotational Doppler shift associated with light beams carrying orbital angular momentum. The effect is evidenced as the broadening of a Hanle electromagnetically induced transparency coherence resonance on Rb vapor when the two incident Laguerre-Gaussian laser beams have opposite topological charges. The observations closely agree with theoretical predictions.

S. Barreiro; J. W. R. Tabosa; H. Failache; A. Lezama

2006-09-12T23:59:59.000Z

137

Airborne Doppler Lidar Wind Field Measurements  

Science Journals Connector (OSTI)

A coherent Doppler lidar has been used in an aircraft to measure the 2-dimensional wind field in a number of different atmospheric situations. The lidar, a pulsed CO2 system, was installed in the NASA Convair 990. Galileo II, and flown in a ...

J. Bilbro; G. Fichtl; D. Fitzjarrald; M. Krause; R. Lee

1984-04-01T23:59:59.000Z

138

A MAGNETIC CALIBRATION OF PHOTOSPHERIC DOPPLER VELOCITIES  

SciTech Connect (OSTI)

The zero point of measured photospheric Doppler shifts is uncertain for at least two reasons: instrumental variations (from, e.g., thermal drifts); and the convective blueshift, a known correlation between intensity and upflows. Accurate knowledge of the zero point is, however, useful for (1) improving estimates of the Poynting flux of magnetic energy across the photosphere, and (2) constraining processes underlying flux cancellation, the mutual apparent loss of magnetic flux in closely spaced, opposite-polarity magnetogram features. We present a method to absolutely calibrate line-of-sight (LOS) velocities in solar active regions (ARs) near disk center using three successive vector magnetograms and one Dopplergram coincident with the central magnetogram. It exploits the fact that Doppler shifts measured along polarity inversion lines (PILs) of the LOS magnetic field determine one component of the velocity perpendicular to the magnetic field, and optimizes consistency between changes in LOS flux near PILs and the transport of transverse magnetic flux by LOS velocities, assuming that ideal electric fields govern the magnetic evolution. Previous calibrations fitted the center-to-limb variation of Doppler velocities, but this approach cannot, by itself, account for residual convective shifts at the limb. We apply our method to vector magnetograms of AR 11158, observed by the Helioseismic and Magnetic Imager aboard the Solar Dynamics Observatory, and find clear evidence of offsets in the Doppler zero point in the range of 50-550 m s{sup -1}. In addition, we note that a simpler calibration can be determined from an LOS magnetogram and Dopplergram pair from the median Doppler velocity among all near-disk-center PIL pixels. We briefly discuss shortcomings in our initial implementation, and suggest ways to address these. In addition, as a step in our data reduction, we discuss the use of temporal continuity in the transverse magnetic field direction to correct apparently spurious fluctuations in resolution of the 180 Degree-Sign ambiguity.

Welsch, Brian T.; Fisher, George H. [Space Sciences Laboratory, University of California, Berkeley, CA 94720-7450 (United States); Sun, Xudong [W. W. Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305 (United States)

2013-03-10T23:59:59.000Z

139

Rotational Doppler effect in left-handed materials  

Science Journals Connector (OSTI)

We explain the rotational Doppler effect associated with light beams carrying with orbital angular momentum in left-handed materials (LHMs). We demonstrate that the rotational Doppler effect in LHMs is unreversed, which is significantly different from the axial Doppler effect. The physics underlying this intriguing effect is the combined contributions of negative phase velocity and the inverse screw of the wave front. We find that the additional Doppler effect caused by Gouy phase and wave-front curvature should be reversed, because of the negative index. In the normal dispersion region, the rotational Doppler effect induces an upstream energy flow but a downstream momentum flow. In the anomalous dispersion region, however, the rotational Doppler effect produces a downstream energy flow but an upstream momentum flow. We theoretically predict that the rotational Doppler effect can induce a transfer of angular momentum of the LHM to orbital angular momentum of the beam.

Hailu Luo; Shuangchun Wen; Weixing Shu; Zhixiang Tang; Yanhong Zou; Dianyuan Fan

2008-09-05T23:59:59.000Z

140

Equatorial spread {ital F} effects on an HF path: Doppler spread, spatial coherence, and frequency coherence  

SciTech Connect (OSTI)

In August 1990 we participated in the Equatorial Ionospheric Studies sounding rocket campaign near Kwajalein Atoll in the equatorial Pacific region. The campaign included measurements of plasma density using rocket probes and coherent and incoherent scatter radar. During the campaign we fielded high-frequency ionospheric sounders over a bistatic path between Maloelap Atoll and Bikini Atoll in the Marshall Islands. The distance between the transmitters and receivers was 700 km; the ionospheric-reflection region was at 10.18; {degree}N, 168.40;{degree}E, near the magnetic equator. We made three types of measurements: Doppler spread and spatial coherence for a single-frequency CW path; frequency coherence of multiple CW paths; and Doppler spread and time-delay spread for a 60-kHz bandwidth path. We obtained such data over a period of 2 weeks for approximately 2 hours each evening; during this period spread {ital F} was common. Fifty percent of the evenings showed Doppler spread of greater than 6 Hz at the {minus}10 dB level (relative to the peak signal power) and greater than 15 Hz at the {minus}30 dB level. Forty percent of the evenings showed spatial coherence distance of less than 180 m in the direction normal to the bistatic path; 40{percent} of the evenings showed spatial coherence of less than 75 m in the direction parallel to the path. Seventy-five percent of the evenings showed coherence bandwidths of less than 1.5 kHz. {copyright} 1999 American Geophysical Union

Fitzgerald, T.J.; Argo, P.E.; Carlos, R.C. [Los Alamos National Laboratory, Los Alamos, New Mexico (United States)] [Los Alamos National Laboratory, Los Alamos, New Mexico (United States)

1999-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "radar doppler spectra" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

Design of a Doppler reflectometer for KSTAR  

SciTech Connect (OSTI)

A Doppler reflectometer has been designed to measure the poloidal propagation velocity on the Korea Superconducting Tokamak Advanced Research (KSTAR) tokamak. It has the operating frequency range of V-band (50-75 GHz) and the monostatic antenna configuration with extraordinary mode (X-mode). The single sideband modulation with an intermediate frequency of 50 MHz is used for the heterodyne measurement with the 200 MHz in-phase and quadrature (I/Q) phase detector. The corrugated conical horn antenna is used to approximate the Gaussian beam propagation and it is installed together with the oversized rectangular waveguides in the vacuum vessel. The first commissioning test of the Doppler reflectometer system on the KSTAR tokamak is planned in the 2014 KSTAR experimental campaign.

Lee, K. D., E-mail: kdlee@nfri.re.kr; Nam, Y. U.; Seo, Seong-Heon; Kim, Y. S. [National Fusion Research Institute, Yuseong, Daejeon 305-333 (Korea, Republic of)

2014-11-15T23:59:59.000Z

142

ROTATIONAL DOPPLER BEAMING IN ECLIPSING BINARIES  

SciTech Connect (OSTI)

In eclipsing binaries the stellar rotation of the two components will cause a rotational Doppler beaming during eclipse ingress and egress when only part of the eclipsed component is covered. For eclipsing binaries with fast spinning components this photometric analog of the well-known spectroscopic Rossiter-McLaughlin effect can exceed the strength of the orbital effect. Example light curves are shown for a detached double white dwarf binary, a massive O-star binary and a transiting exoplanet case, similar to WASP-33b. Inclusion of the rotational Doppler beaming in eclipsing systems is a prerequisite for deriving the correct stellar parameters from fitting high-quality photometric light curves and can be used to determine stellar obliquities as well as, e.g., an independent measure of the rotational velocity in those systems that may be expected to be fully synchronized.

Groot, Paul J., E-mail: pgroot@astro.ru.nl [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States)

2012-01-20T23:59:59.000Z

143

Radar range measurements in the atmosphere.  

SciTech Connect (OSTI)

The earth's atmosphere affects the velocity of propagation of microwave signals. This imparts a range error to radar range measurements that assume the typical simplistic model for propagation velocity. This range error is a function of atmospheric constituents, such as water vapor, as well as the geometry of the radar data collection, notably altitude and range. Models are presented for calculating atmospheric effects on radar range measurements, and compared against more elaborate atmospheric models.

Doerry, Armin Walter

2013-02-01T23:59:59.000Z

144

Schwarzschild orbital topography and high Doppler blueshifts  

Science Journals Connector (OSTI)

... high Doppler blueshift of forward light emission from material particles in circular orbit in a Schwarzschild field at and near r = 3GM/c2, which they claim is the radius ... supposed effect rests on a basic confusion concerning the orbital topography and energetics in the Schwarzschild field. Outside the event horizon, at r = 2G7V//C2, there are three ...

W. R. STOEGER

1975-03-20T23:59:59.000Z

145

ECE/METR 6613: Weather Radar Polarimetry Prereq.: Graduate status  

E-Print Network [OSTI]

(guzhang1@ou.edu), (405)325-3507 Text: G. Zhang: Lecture notes ­ Weather Radar Polarimetry with Matlab, weather radar interferometry, multi-frequency/site radar techniques. Grading Homeworks 30% Projects 40

Droegemeier, Kelvin K.

146

Radar Testbed Characterization for Evaluation of Modulated Scatterer Concepts  

E-Print Network [OSTI]

The following research explores the concepts of communication-embedded radar with an emphasis on radar operation and modulated scatterer concepts. Once firmly established the concept of communication via radar backscatter ...

Casper, Matt

2010-05-27T23:59:59.000Z

147

Sub-Doppler Stark Spectroscopy in the A?X (1,0) Band of CN  

SciTech Connect (OSTI)

The effect of external electric fields has been measured in hyperfine-resolved sub-Doppler transitions in the A {sup 2}{Pi}-X {sup 2}{Sigma} (1,0) band of the CN radical near 10900 cm{sup -1}. Static electric fields less than 1 kV/cm are sufficient to mix the most closely spaced {Lambda}-dpublets in the A state, leading to Stark spectra with both new and shifted resonances. Simulations of the saturation-dip Stark spectral line profiles allow extraction of the A-state permanent electric dipole moment with a magnitude of 0.06 {+-} 0.02 D.

Hall, G.E.; Hause, M.L.; Sears, T.J.

2009-11-26T23:59:59.000Z

148

Radar remote sensing of the lower atmosphere  

E-Print Network [OSTI]

from a numerical weather prediction (NWP) model is examined.numerical weather prediction and empirical site-specific radar clutter models,”

Karimian, Ali

2012-01-01T23:59:59.000Z

149

Radar investigation of the Hockley salt dome  

E-Print Network [OSTI]

: Geophysics RADAR INVESTIGATION OF THE HOCKLEY SALT DOME A Thesis by UAMES ANDREW HLUCHANEK A'pproved as to style and content by: (Head of Departme t ? Member) May 1. 973 ABSTRACT Radar investigation of the Hockley Salt Dome. . (Nay, 1973) James... Andrew Hluchanek, B. S. , Texas A&M University Directed by: Dr. Robert R. Unterberger Radar probing through salt was accomplished at 17 radar stations established in the United Salt Company mine at Hockley, Texas. The top of the salt dom is mapped...

Hluchanek, James Andrew

2012-06-07T23:59:59.000Z

150

Unusual Doppler effect in He II  

Science Journals Connector (OSTI)

Many years ago Khalatnikov described unusual properties of the Doppler shift for the second sound in He II, first of all the ‘‘back-entrainment’’ effect: at some temperatures (at the beginning of the roton region) the center of the spreading sound moves in the direction opposite to the normal-component velocity vn [?u2=?(T)vn, ?(T?0.6 K)Doppler shift of the first and fourth sounds as a trivial, ‘‘kinematic’’ effect: the center of the spreading sound moves with the velocity of the liquid as a whole [?u1,4?j/p=(1-?n/?)vs]. We show that the real situation is quite different. We find (1) the coefficient K in the Doppler-shift expression, ?u1,4=(1-K1,4?n/?)vs, substantially differs from the kinematic value K=1:?K?max reaches some tens. (2) K1(T) and K4(T) have different (qualitatively opposite) nontrivial temperature dependences, in particular a high peak (modulo) at the beginning of the roton region. (3) K1,4(T) can be negative: K1effect: the center of the spreading sound moves faster than the flowing superfluid part of the liquid itself.

Y. A. Nepomnyashchy

1993-01-01T23:59:59.000Z

151

Doppler Effect in Resonant Photoemission from SF6: Correlation between Doppler Profile and Auger Emission Anisotropy  

Science Journals Connector (OSTI)

Fragmentation of the SF6 molecule upon F 1s excitation has been studied by resonant photoemission. The F atomiclike Auger line exhibits the characteristic Doppler profile that depends on the direction of the photoelectron momentum relative to the polarization vector of the radiation as well as on the photon energy. The measured Doppler profiles are analyzed by the model simulation that takes account of the anisotropy of the Auger emission in the molecular frame. The Auger anisotropy extracted from the data decreases with an increase in the F-SF5 internuclear distance.

M. Kitajima; K. Ueda; A. De Fanis; T. Furuta; H. Shindo; H. Tanaka; K. Okada; R. Feifel; S. L. Sorensen; F. Gel’mukhanov; A. Baev; H. Ågren

2003-11-20T23:59:59.000Z

152

Ultra-wideband radar sensors and networks  

DOE Patents [OSTI]

Ultra wideband radar motion sensors strategically placed in an area of interest communicate with a wireless ad hoc network to provide remote area surveillance. Swept range impulse radar and a heart and respiration monitor combined with the motion sensor further improves discrimination.

Leach, Jr., Richard R; Nekoogar, Faranak; Haugen, Peter C

2013-08-06T23:59:59.000Z

153

Effect of speckle pattern on laser Doppler velocimeters  

Science Journals Connector (OSTI)

The effect of speckle pattern on laser Doppler velocimeters is studied theoretically and experimentally. We have found that dynamic speckle patterns can cause error in velocity...

Lv, Liang; Gui, Huaqiao; Zhao, Tianpeng; Xu, Jun; He, Deyong; Wang, Anting; Li, Feng; Ming, Hai; Xie, Jianping

2005-01-01T23:59:59.000Z

154

Stratus Cloud Drizzle Retrieval During SHEBA from MMCR Doppler...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

when the updrafts and downdrafts are averaged out. The second contribution is the effect of turbulence on the spread of the Doppler spectrum. Both of these contributions...

155

Design of new seismometer based on laser Doppler effect  

Science Journals Connector (OSTI)

In order to improve the resolution of seismic acquisition, a new seismic acquisition system based on tangential laser Doppler effect with an optimized differential optical...

Du, Zhenhui; Huang, Fuxiang; Jiang, Chengzhi; Tao, Zhifei; Gao, Hua; Lv, Lina

2004-01-01T23:59:59.000Z

156

Time-resolved fuel injector flow characterisation based on 3D laser Doppler vibrometry  

E-Print Network [OSTI]

In order to enable investigations of the fuel flow inside unmodified injectors, we have developed a new experimental approach to measure time-resolved vibration spectra of diesel nozzles using a three dimensional laser vibrometer. The technique we propose is based on the triangulation of the vibrometer and fuel pressure transducer signals, and enables the quantitative characterisation of quasi-cyclic internal flows without requiring modifications to the injector, the working fluid, or limiting the fuel injection pressure. The vibrometer, which uses the Doppler effect to measure the velocity of a vibrating object, was used to scan injector nozzle tips during the injection event. The data were processed using a discrete Fourier transform to provide time-resolved spectra for valve-closed-orifice, minisac and microsac nozzle geometries, and injection pressures ranging from 60 to 160MPa, hence offering unprecedented insight into cyclic cavitation and internal mechanical dynamic processes. A peak was consistently f...

Crua, Cyril

2015-01-01T23:59:59.000Z

157

PRECISE DOPPLER MONITORING OF BARNARD'S STAR  

SciTech Connect (OSTI)

We present 248 precise Doppler measurements of Barnard's Star (Gl 699), the second nearest star system to Earth, obtained from Lick and Keck Observatories during the 25 years between 1987 and 2012. The early precision was 20 m s{sup -1} but was 2 m s{sup -1} during the last 8 years, constituting the most extensive and sensitive search for Doppler signatures of planets around this stellar neighbor. We carefully analyze the 136 Keck radial velocities spanning 8 years by first applying a periodogram analysis to search for nearly circular orbits. We find no significant periodic Doppler signals with amplitudes above {approx}2 m s{sup -1}, setting firm upper limits on the minimum mass (Msin i) of any planets with orbital periods from 0.1 to 1000 days. Using a Monte Carlo analysis for circular orbits, we determine that planetary companions to Barnard's Star with masses above 2 M {sub Circled-Plus} and periods below 10 days would have been detected. Planets with periods up to 2 years and masses above 10 M {sub Circled-Plus} (0.03 M {sub Jup}) are also ruled out. A similar analysis allowing for eccentric orbits yields comparable mass limits. The habitable zone of Barnard's Star appears to be devoid of roughly Earth-mass planets or larger, save for face-on orbits. Previous claims of planets around the star by van de Kamp are strongly refuted. The radial velocity of Barnard's Star increases with time at 4.515 {+-} 0.002 m s{sup -1} yr{sup -1}, consistent with the predicted geometrical effect, secular acceleration, that exchanges transverse for radial components of velocity.

Choi, Jieun; Marcy, Geoffrey W.; Howard, Andrew W.; Isaacson, Howard [Department of Astronomy, University of California, Berkeley, CA 94720 (United States)] [Department of Astronomy, University of California, Berkeley, CA 94720 (United States); McCarthy, Chris [Department of Physics and Astronomy, San Francisco State University, San Francisco, CA 94132 (United States)] [Department of Physics and Astronomy, San Francisco State University, San Francisco, CA 94132 (United States); Fischer, Debra A. [Department of Astronomy, Yale University, New Haven, CT 06520-8101 (United States)] [Department of Astronomy, Yale University, New Haven, CT 06520-8101 (United States); Johnson, John A. [Department of Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States)] [Department of Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Wright, Jason T., E-mail: jieun_eb@berkeley.edu [Department of Astronomy, The Pennsylvania State University, University Park, PA 16802 (United States)

2013-02-20T23:59:59.000Z

158

Doppler effect of time and space  

E-Print Network [OSTI]

This paper shows as the relativistic Doppler effect can be extended also to time and space associated to moving bodies. This extension derives from the analysis of the wave-fronts of the light emitted by a moving source in inertial motion in the empty space, as viewed from the stationary reference. Indeed, time and space can be represented by the same vector quantities, which appear asymmetrical in forward and back direction along the path of the moving body. Consequently, the whole size of the moving bodies dilates along the direction of their motion, as their path. Thought experiments and real facts demonstrate this issue.

Giovanni Zanella

2010-10-28T23:59:59.000Z

159

EMSL - emission spectra  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

emission-spectra en Structures and Stabilities of (MgO)n Nanoclusters. http:www.emsl.pnl.govemslwebpublicationsstructures-and-stabilities-mgon-nanoclusters

160

Technical Note: Improved implementation of doppler broadening in MCNP5  

SciTech Connect (OSTI)

Purpose: Incoherent scattering has a substantial effect on spectroscopic measurements and simulations. Many general-purpose Monte Carlo codes include models that account for the effects of bound electrons on incoherent scattering, including Doppler broadening (DB). This work investigates the DB model used in the Monte Carlo N-particle transport code (MCNP5). Methods: Simulations were run with three versions of MCNP5: v1.51, v1.60, and a modified form of v1.60 (v1.60m). All simulations used the MCPLIB04 photon data library, which presents the electron subshell data for incoherent scattering in the form of a probability density function. In v1.60m, the source code was altered to sample the electron subshell from a cumulative density function instead. Each version of the code was tested using an identical set of simulations that investigated DB in a slab of silicon at scattering angles of 15 Degree-Sign , 30 Degree-Sign , and 45 Degree-Sign . For each angle, simulations were run for multiple energies between 200 keV and 800 keV. The spectrum of singly-scattered photons at the exit of the slab was scored. Spectra were analytically calculated for comparison. Results: In v1.51, DB was modeled for incident photon energies below 760 keV, 384 keV, and 260 keV at scattering angles of 15 Degree-Sign , 30 Degree-Sign , and 45 Degree-Sign , respectively. Above these energy thresholds, v1.51 did not model DB. The spectra calculated using v1.60 and v1.60m exhibited DB for all energy-angle combinations; however, v1.60m, exhibited more energy broadening than did v1.60. The spectra calculated with v1.60m agreed with the analytical calculations. Conclusions: MCNP5 v1.51 and v1.60 model partial broadening when used with the MCPLIB04 data library. MCNP5 v1.60m models DB more accurately due to the form of the electron subshell data. In response to these results, Los Alamos National Laboratory has released a new photon data library, MCPLIB84, that presents the electron subshell data in cumulative distribution form. MCNP5 v1.60 should be used with this library when incoherent scattering has a significant impact on simulation results.

Bartol, Laura J.; DeWerd, Larry A. [University of Wisconsin-Madison, Department of Medical Physics, Madison, Wisconsin 53705 (United States)

2012-09-15T23:59:59.000Z

Note: This page contains sample records for the topic "radar doppler spectra" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Characterizing Ocean Turbulence from Argo, Acoustic Doppler, and Simulation Data  

E-Print Network [OSTI]

. TurbSim models statistics at the height of a turbine hub (5m) well, but do not model coherent eventsCharacterizing Ocean Turbulence from Argo, Acoustic Doppler, and Simulation Data Katherine Mc Ocean Turbulence from Argo, Acoustic Doppler, and Simulation Data written by Katherine McCaffrey has

Fox-Kemper, Baylor

162

Imaging doppler velocimeter with downward heterodyning in the optical domain  

DOE Patents [OSTI]

In a Doppler velocimeter, the incoming Doppler-shifted beams are heterodyned to reduce their frequencies into the bandwidth of a digital camera. This permits the digital camera to produce at every sampling interval a complete two-dimensional array of pixel values. This sequence of pixel value arrays provides a velocity image of the target.

Reu, Phillip L; Hansche, Bruce D

2013-05-21T23:59:59.000Z

163

"An analysis of the classical Doppler Effect"[1] revisited  

E-Print Network [OSTI]

After having shown that the formula which describes the Doppler effect in the general case holds only in the case of the "very high" frequency assumption, we derive free of assumptions Doppler formulas for two scenarios presented in the revisited paper.

Bernhard Rothenstein; Corina Nafornita

2004-03-26T23:59:59.000Z

164

The Doppler Effect in the Molecular Scattering of Radiation  

Science Journals Connector (OSTI)

... the irregular alterations in the wave-length of the scattered radiation produced (in accordance with Doppler's principle) by the thermal movements of the molecules. There is one interesting feature ... ) by the thermal movements of the molecules. There is one interesting feature of the Doppler ...

C. V. RAMAN

1919-05-01T23:59:59.000Z

165

Scanning Cloud Radar Observations at Azores: Preliminary 3D Cloud Products  

SciTech Connect (OSTI)

The deployment of the Scanning W-Band ARM Cloud Radar (SWACR) during the AMF campaign at Azores signals the first deployment of an ARM Facility-owned scanning cloud radar and offers a prelude for the type of 3D cloud observations that ARM will have the capability to provide at all the ARM Climate Research Facility sites by the end of 2010. The primary objective of the deployment of Scanning ARM Cloud Radars (SACRs) at the ARM Facility sites is to map continuously (operationally) the 3D structure of clouds and shallow precipitation and to provide 3D microphysical and dynamical retrievals for cloud life cycle and cloud-scale process studies. This is a challenging task, never attempted before, and requires significant research and development efforts in order to understand the radar's capabilities and limitations. At the same time, we need to look beyond the radar meteorology aspects of the challenge and ensure that the hardware and software capabilities of the new systems are utilized for the development of 3D data products that address the scientific needs of the new Atmospheric System Research (ASR) program. The SWACR observations at Azores provide a first look at such observations and the challenges associated with their analysis and interpretation. The set of scan strategies applied during the SWACR deployment and their merit is discussed. The scan strategies were adjusted for the detection of marine stratocumulus and shallow cumulus that were frequently observed at the Azores deployment. Quality control procedures for the radar reflectivity and Doppler products are presented. Finally, preliminary 3D-Active Remote Sensing of Cloud Locations (3D-ARSCL) products on a regular grid will be presented, and the challenges associated with their development discussed. In addition to data from the Azores deployment, limited data from the follow-up deployment of the SWACR at the ARM SGP site will be presented. This effort provides a blueprint for the effort required for the development of 3D cloud products from all new SACRs that the program will deploy at all fixed and mobile sites by the end of 2010.

Kollias, P.; Johnson, K.; Jo, I.; Tatarevic, A.; Giangrande, S.; Widener, K.; Bharadwaj, N.; Mead, J.

2010-03-15T23:59:59.000Z

166

E-Print Network 3.0 - al ecocardiograma doppler Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

and ionized atmosphere. Those waves have been Summary: a variety of techniques, such as HF Doppler sounding or GPS receivers. The HF Doppler technique... the performances of the...

167

Use of GPS network data for HF Doppler measurements interpretation  

E-Print Network [OSTI]

The method of measurement of Doppler frequency shift of ionospheric signal - HF Doppler technique - is one of well-known and widely used methods of ionosphere research. It allows to research various disturbances in the ionosphere. There are some sources of disturbances in the ionosphere. These are geomagnetic storms, solar flashes, metrological effects, atmospheric waves. This method allows to find out the influence of earthquakes, explosions and other processes on the ionosphere, which occur near to the Earth. HF Doppler technique has the high sensitivity to small frequency variations and the high time resolution, but interpretation of results is difficult. In this work we make an attempt to use GPS data for Doppler measurements interpretation. Modeling of Doppler frequency shift variations with use of TEC allows to separate ionosphere disturbances of medium scale.

Petrova, Inna R; Latypov, Ruslan R

2014-01-01T23:59:59.000Z

168

Real-time bulk-motion-correction free Doppler variance optical coherence tomography for choroidal capillary vasculature imaging  

E-Print Network [OSTI]

The effect of sample movement on the color Doppler andmotion effect can be neglected here. The Doppler variance

Liu, Gangjun; Qi, Wenjuan; Yu, Lingfeng; Chen, Zhongping

2011-01-01T23:59:59.000Z

169

Iterative synthetic aperture radar imaging algorithms   

E-Print Network [OSTI]

Synthetic aperture radar is an important tool in a wide range of civilian and military imaging applications. This is primarily due to its ability to image in all weather conditions, during both the day and the night, ...

Kelly, Shaun Innes

2014-06-30T23:59:59.000Z

170

Asymmetric radar echo patterns from insects.  

Science Journals Connector (OSTI)

Radar echoes from insects, birds, and bats in the atmosphere exhibit both symmetry and asymmetry in polarimetric patterns. Symmetry refers to similar magnitudes of polarimetric variables at opposite azimuths, and asymmetry relegates to differences ...

Valery M. Melnikov; Michael J. Istok; John K. Westbroo

171

Radar remote sensing of the lower atmosphere  

E-Print Network [OSTI]

radar ducts over the Persian Gulf,” J. Appl. Meteor. , vol.of the world. The Persian Gulf, the Mediterranean andifornia and 50% in the Persian Gulf [41]. Efforts in remote

Karimian, Ali

2012-01-01T23:59:59.000Z

172

How Radar Works | Open Energy Information  

Open Energy Info (EERE)

Works Jump to: navigation, search OpenEI Reference LibraryAdd to library Web Site: How Radar Works Author Institute For Geophysics Published Institute For Geophysics, 2013 DOI Not...

173

Laser Doppler vibrometer employing active frequency feedback  

SciTech Connect (OSTI)

We present a heterodyne Michelson interferometer for vibration measurement in which feedback is used to obviate the need to unwrap phase data. The Doppler shift of a vibrating target mirror is sensed interferometrically and compensated by means of a voltage-controlled oscillator driving an acousto-optic modulator. For frequencies within the servo bandwidth, the oscillator control voltage provides a direct measurement of the target velocity. Outside the servo bandwidth, phase-sensitive detection is used to evaluate high-frequency displacements. This approach is of great interest for the frequently-occurring situation where vibration amplitudes at low frequency exceed an optical wavelength, but knowledge of the vibration spectrum at high frequency is important as well.

Chijioke, Akobuije; Lawall, John

2008-09-20T23:59:59.000Z

174

Spectra over complex terrain  

SciTech Connect (OSTI)

Spectra have been measured over land downwind of a water surface, over hilltops and escarpments, and over rolling farmland. The following hypotheses can be used to explain the differences between these spectra. (1) For wavelengths short compared to the fetch over the new terrain, spectral densities are in equilibrium with the new terrain. (2) For wavelengths long compared to this fetch, spectral densities remain unchanged if the ground is horizontal. If the flow is over a steep hill, the low-frequency structure is modified by distortion of the mean flow, with the longitudinal component losing energy relative to the lateral and vertical components. Because vertical-velocity spectra contain relatively less low-frequency energy than horizontal-velocity spectra, energetic vertical-velocity fluctuations tend to be in equilibrium with local terrain.

Panofsky, H.A.; Larko, D.; Lipschutz, R.; Stone, G.

1981-01-01T23:59:59.000Z

175

Relativistic formulation for the Doppler-broadened line profile  

SciTech Connect (OSTI)

Profiles of spectral lines due to the thermal motion of light-emitting particles are formulated based on the classical and the relativistic Doppler effects, respectively. For the classical case, the well-known Doppler-broadened line profile is reproduced. For the relativistic case, the line profile obtained is asymmetrically broadened with increasing temperature. However, the peak frequency remains unshifted, in contrast to blueshifted, as has been predicted in the current literature. Reasoning is given as to why the relativistic Doppler-broadened line profile currently accepted is probably invalid.

Huang, Young-Sea; Chiue, Juang-Han; Huang, Yi-Chi; Hsiung, Te-Chih [Department of Physics, Soochow University, Shih-Lin, Taipei, Taiwan (China); Department of Physics, National Central University, Chung-Li, Taiwan (China)

2010-07-15T23:59:59.000Z

176

E-Print Network 3.0 - anomalous doppler effect Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

effect Search Powered by Explorit Topic List Advanced Search Sample search results for: anomalous doppler effect...

177

Verification of three-dimensional laser Doppler velocimeter measurements  

Science Journals Connector (OSTI)

An experimental comparison method is proposed for the verification of mean flow and turbulence measurements obtained with a three-dimensional laser Doppler velocimeter system. Such measurements can include large ...

R. D. Mehta

1990-03-01T23:59:59.000Z

178

Comparison of 2- and 10-µm Coherent Doppler Lidar Performance  

Science Journals Connector (OSTI)

The performance of 2- and 10-µm coherent Doppler lidar is presented in terms of the statistical distribution of the maximum-likelihood velocity estimator from simulations for fixed range resolution and fixed velocity search space as a function of ...

Rod Frehlich

1995-04-01T23:59:59.000Z

179

Doppler optical coherence microscopy for studies of cochlear mechanics  

E-Print Network [OSTI]

The possibility of measuring subnanometer motions with micron scale spatial resolution in the intact mammalian cochlea using Doppler optical coherence microscopy (DOCM) is demonstrated. A novel DOCM system is described ...

Hong, Stanley S.

180

Radiation pressure on a moving body: beyond the Doppler effect  

Science Journals Connector (OSTI)

The dependence of macroscopic radiation pressure on the velocity of the object being pushed is commonly attributed to the Doppler effect. This need not be the case, and here we...

Horsley, S A R; Artoni, M; Rocca, G C La

2012-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "radar doppler spectra" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Doppler electron velocimetry : notes on creating a practical tool.  

SciTech Connect (OSTI)

The Doppler electron velocimeter (DEV) has been shown to be theoretically possible. This report attempts to answer the next logical question: Is it a practical instrument? The answer hinges upon whether enough electrons are available to create a time-varying Doppler current to be measured by a detector with enough sensitivity and bandwidth. The answer to both of these questions is a qualified yes. A target Doppler frequency of 1 MHz was set as a minimum rate of interest. At this target a theoretical beam current signal-to-noise ratio of 25-to-1 is shown for existing electron holography equipment. A detector is also demonstrated with a bandwidth of 1-MHz at a current of 10 pA. Additionally, a Linnik-type interferometer that would increase the available beam current is shown that would offer a more flexible arrangement for Doppler electron measurements over the traditional biprism.

Reu, Phillip L.; Milster, Tom (University of Arizona)

2008-11-01T23:59:59.000Z

182

Moving interference patterns created using the angular Doppler-effect  

Science Journals Connector (OSTI)

We use the angular Doppler-effect to obtain stable frequency shifts from below one Hertz to hundreds of Hertz in the optical domain, constituting a control of 1 part in 1014. For the...

Arlt, J; MacDonald, Michael; Paterson, L; Sibbett, W; Dholakia, K; Volke-Sepulveda, K

2002-01-01T23:59:59.000Z

183

Extracting Fish and Water Velocity from Doppler Profiler Data  

E-Print Network [OSTI]

Extracting Fish and Water Velocity from Doppler Profiler Data �º Ð 1 ¸ � � �¹ � Ý�¹� � 2 1 to measure fish swimming speeds. This is possible when fish form schools that are large enough so that the multiple Doppler sonar beams are sampling the fish speeds at the same time. In situations where fish

deYoung, Brad

184

Satellite vibration measurements with an autodyne CO2 laser radar  

Science Journals Connector (OSTI)

Vibration signatures of the Low Power Atmospheric Compensation Experiment satellite were obtained with a ground-based CO2 laser radar. The laser radar operated in a cw mode...

Schultz, K I; Kocher, D G; Daley, J A; Theriault, J R; Spinks, J; Fisher, S

1994-01-01T23:59:59.000Z

185

ARM - Field Campaign - DC-8 Cloud Radar Campaign  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

the JPLUMass 95 GHz Airborne Cloud Radar (ACR) and a nadir pointing PRT-5 IR thermometer. Ground based millimeter-wave cloud radars operating at 33 GHz, 95 GHz, 94 GHz and...

186

First Observations of Tracking Clouds Using Scanning ARM Cloud Radars  

Science Journals Connector (OSTI)

Tracking clouds using scanning cloud radars can help to document the temporal evolution of cloud properties well before large-drop formation (weather radar “first echo”). These measurements also complement cloud and precipitation tracking using ...

Paloma Borque; Pavlos Kollias; Scott Giangrande

2014-12-01T23:59:59.000Z

187

High resolution laser induced fluorescence Doppler velocimetry utilizing saturated absorption spectroscopy  

SciTech Connect (OSTI)

A high resolution laser induced fluorescence (LIF) system has been developed to measure the flow velocity field of neutral particles in an electron-cyclotron-resonance argon plasma. The flow velocity has been determined by the Doppler shift of the LIF spectrum, which is proportional to the velocity distribution function. Very high accuracy in velocity determination has been achieved by installing a saturated absorption spectroscopy unit into the LIF system, where the absolute value and scale of laser wavelength are determined by using the Lamb dip and the fringes of a Fabry-Perot interferometer. The minimum detectable flow velocity of a newly developed LIF system is {+-}2 m/s, and this performance remains unchanged in a long-time experiment. From the radial measurements of LIF spectra of argon metastable atoms, it is found that there exists an inward flow of neutral particles associated with neutral depletion.

Aramaki, Mitsutoshi [Department of Electrical Engineering and Computer Science, Nagoya University, Nagoya 464-8603 (Japan); Ogiwara, Kohei; Etoh, Shuzo [Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Kasuga 816-8580 (Japan); Yoshimura, Shinji [National Institute for Fusion Science, Toki 509-5292 (Japan); Tanaka, Masayoshi Y. [Department of Advanced Energy Engineering Science, Kyushu University, Kasuga 816-8580 (Japan)

2009-05-15T23:59:59.000Z

188

Some non-precipitation radar echoes as observed by CPS-9 radar  

E-Print Network [OSTI]

's curvature, which caused the cell to lie below the radar bean. The decelerating gust line passed the radar station at 2304Z; its position at 2322Z is shown in (Figure ld, 5 mi markers). A wind-direction change of 60 deg and a wind speed in- 35 crease... markers) formed behind the second. The parent cell moved some 10 mi during the hour of its life cycle, and the gust lines dissipated before reaching the radar. At 0240Z the aerovane (not shown) showed a 55 deg shift in wind direction with a speed of 5...

Luckenbach, Guenther Edward

2012-06-07T23:59:59.000Z

189

DOPPLER SIGNATURES OF THE ATMOSPHERIC CIRCULATION ON HOT JUPITERS  

SciTech Connect (OSTI)

The meteorology of hot Jupiters has been characterized primarily with thermal measurements, but recent observations suggest the possibility of directly detecting the winds by observing the Doppler shift of spectral lines seen during transit. Motivated by these observations, we show how Doppler measurements can place powerful constraints on the meteorology. We show that the atmospheric circulation-and Doppler signature-of hot Jupiters splits into two regimes. Under weak stellar insolation, the day-night thermal forcing generates fast zonal jet streams from the interaction of atmospheric waves with the mean flow. In this regime, air along the terminator (as seen during transit) flows toward Earth in some regions and away from Earth in others, leading to a Doppler signature exhibiting superposed blueshifted and redshifted components. Under intense stellar insolation, however, the strong thermal forcing damps these planetary-scale waves, inhibiting their ability to generate jets. Strong frictional drag likewise damps these waves and inhibits jet formation. As a result, this second regime exhibits a circulation dominated by high-altitude, day-to-night airflow, leading to a predominantly blueshifted Doppler signature during transit. We present state-of-the-art circulation models including non-gray radiative transfer to quantify this regime shift and the resulting Doppler signatures; these models suggest that cool planets like GJ 436b lie in the first regime, HD 189733b is transitional, while planets hotter than HD 209458b lie in the second regime. Moreover, we show how the amplitude of the Doppler shifts constrains the strength of frictional drag in the upper atmospheres of hot Jupiters. If due to winds, the {approx}2 km s{sup -1} blueshift inferred on HD 209458b may require drag time constants as short as 10{sup 4}-10{sup 6} s, possibly the result of Lorentz-force braking on this planet's hot dayside.

Showman, Adam P.; Lewis, Nikole K. [Department of Planetary Sciences and Lunar and Planetary Laboratory, The University of Arizona, 1629 University Boulevard, Tucson, AZ 85721 (United States)] [Department of Planetary Sciences and Lunar and Planetary Laboratory, The University of Arizona, 1629 University Boulevard, Tucson, AZ 85721 (United States); Fortney, Jonathan J. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States)] [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Shabram, Megan, E-mail: showman@lpl.arizona.edu [Department of Astronomy, University of Florida, 211 Bryant Space Science Center, Gainesville, FL 32611-2055 (United States)] [Department of Astronomy, University of Florida, 211 Bryant Space Science Center, Gainesville, FL 32611-2055 (United States)

2013-01-01T23:59:59.000Z

190

USAGE OF RADARS FOR WIND ENERGY APPICATIONS Determine the benefit of using radar observations for wind energy applications by  

E-Print Network [OSTI]

USAGE OF RADARS FOR WIND ENERGY APPICATIONS TASK: Determine the benefit of using radar observations for wind energy applications by analyzing i) the resolution effects and ii) sensitivity effects of weather radar systems. MOTIVATION: Wind energy applications strongly focus high-resolution wind observations

191

A Comparison of ARM Cloud Radar Profiles with MMF Simulated Radar...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

MMF Simulated Radar Profiles as a Function of the Large-Scale Atmospheric State Roger Marchand and Thomas Ackerman Joint Institute for the Study of the Atmosphere and Ocean...

192

Signal to Noise Analysis of iRadar sensors  

SciTech Connect (OSTI)

This document follows my process of testing; comparing; and contrasting several iRadars signal to noise ratios for both HH and VV polarization. A brief introduction is given explaining the basics of iRadar technology and what data I was collecting. The process section explains the steps I took to collect my data along with any procedures I followed. The analysis section compares and contrasts five different radars and the two different polarizations. The analysis also details the radars viewing limitations and area. Finally, the report delves into the effects of two radars interfering with each other. A conclusion goes over the success and findings of the project.

Fritzke, A; Top, P

2009-09-10T23:59:59.000Z

193

Leading neutron spectra  

E-Print Network [OSTI]

It is shown that the observation of the spectra of leading neutrons from proton beams can be a good probe of absorptive and migration effects. We quantify how these effects modify the Reggeized pion-exchange description of the measurements of leading neutrons at HERA. We are able to obtain a satisfactory description of all the features of these data. We also briefly discuss the corresponding data for leading baryons produced in hadron-hadron collisions.

A. B. Kaidalov; V. A. Khoze; A. D. Martin; M. G. Ryskin

2006-02-23T23:59:59.000Z

194

Doppler effect in the oscillator radiation process in the medium  

E-Print Network [OSTI]

The purpose of this paper is to investigate the radiation process of the charged particle passing through an external periodic field in a dispersive medium. In the optical range of spectrum we will consider two cases: first, the source has not eigenfrequency, and second, the source has eigenfrequency. In the first case, when the Cherenkov radiation occurs, the non-zero eigenfrequency produces a paradox for Doppler effect. It is shown that the absence of the eigenfrequency solves the paradox known in the literature. The question whether the process is normal (i.e. hard photons are being radiated under the small angles) or anomalous depends on the law of the medium dispersion. When the source has an eigenfrequency the Doppler effects can be either normal or anomalous. In the X-ray range of the oscillator radiation spectrum we have two photons radiated under the same angle- soft and hard. In this case the radiation obeys to so-called complicated Doppler effect, i.e. in the soft photon region we have anomalous Doppler effect and in the hard photon region we have normal Doppler effect.

Lekdar Gevorgian; Valeri Vardanyan

2011-02-25T23:59:59.000Z

195

Doppler effects in resonant x-ray Raman scattering  

Science Journals Connector (OSTI)

Theory for Doppler effects in resonant x-ray Raman scattering (RXS) is presented. It is shown that the “electron” Doppler effect is important in nonradiative RXS for decay transitions between continuum nuclear states lying above the dissociation threshold, and that the averaging of the RXS cross section over molecular orientations can lead to strong non-Lorentzian broadenings of the atomiclike resonances. The Doppler effect is found to give a unique possibility to distinguish dissociating identical atoms, because different peaks correspond to atoms with opposite Doppler shifts. Spectral features of the atomiclike profile are predicted and analyzed. Strong oscillations of the RXS cross section will occur as a consequence of the interference of the Auger electrons. Due to the Doppler effect and the interference, the atomiclike profile can be associated with supernarrow spectral features, the width of which goes below the lifetime broadening and is practically independent of the spectral distribution of the incident radiation. As another consequence of the oscillations and strong anisotropy caused by the interference, we predict parity selection rules for Auger decay transitions in both bound and dissociative systems. The corresponding experiments can be realized by measurements of resonant Auger of surface adsorbed molecules and for molecules by the electron-ion coincidence technique.

Faris Gel’mukhanov; Hans Ågren; Pawe? Sa?ek

1998-04-01T23:59:59.000Z

196

Impact of Airborne Doppler Radar Data Assimilation on the Numerical Simulation of Intensity Changes of Hurricane Dennis near a Landfall  

E-Print Network [OSTI]

of Utah, Salt Lake City, Utah JUANZHEN SUN National Center for Atmospheric Research, Boulder, Colorado, devastate coastal regions, and cause floods and erosion inland through torrential rainfall, high winds

Pu, Zhaoxia

197

Life Cycle of a Mesoscale Circular Gust Front Observed by a C-Band Doppler Radar in West Africa  

E-Print Network [OSTI]

On 10 July 2006, during the Special Observation Period (SOP) of the African Monsoon Multidisciplinary Analysis (AMMA) campaign, a small convective system initiated over Niamey and propagated westward in the vicinity of ...

Lothon, Marie

198

Generating nonlinear FM chirp waveforms for radar.  

SciTech Connect (OSTI)

Nonlinear FM waveforms offer a radar matched filter output with inherently low range sidelobes. This yields a 1-2 dB advantage in Signal-to-Noise Ratio over the output of a Linear FM waveform with equivalent sidelobe filtering. This report presents design and implementation techniques for Nonlinear FM waveforms.

Doerry, Armin Walter

2006-09-01T23:59:59.000Z

199

Ocean Surface Currents Mapped by Radar  

Science Journals Connector (OSTI)

...frequency range 25 to 26 Mhz for our first series of...whereas at lower frequencies atmospheric noise seen by the radar...1/2 thing, above 25 Mhz ionospheri-cally propagated...frequency be-tween 25 and 35 Mhz (in 200-khz in-crements), but...

D. E. Barrick; M. W. Evans; B. L. Weber

1977-10-14T23:59:59.000Z

200

Motion Measurement for Synthetic Aperture Radar.  

SciTech Connect (OSTI)

Synthetic Aperture Radar (SAR) measures radar soundings from a set of locations typically along the flight path of a radar platform vehicle. Optimal focusing requires precise knowledge of the sounding source locations in 3 - D space with respect to the target scene. Even data driven focusing techniques (i.e. autofocus) requires some degree of initial fidelity in the measurements of the motion of the radar. These requirements may be quite stringent especially for fine resolution, long ranges, and low velocities. The principal instrument for measuring motion is typically an Inertial Measurement Unit (IMU), but these instruments have inherent limi ted precision and accuracy. The question is %22How good does an IMU need to be for a SAR across its performance space?%22 This report analytically relates IMU specifications to parametric requirements for SAR. - 4 - Acknowledgements Th e preparation of this report is the result of a n unfunded research and development activity . Although this report is an independent effort, it draws heavily from limited - release documentation generated under a CRADA with General Atomics - Aeronautical System, Inc. (GA - ASI), and under the Joint DoD/DOE Munitions Program Memorandum of Understanding. Sandia National Laboratories is a multi - program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of En ergy's National Nuclear Security Administration under contract DE - AC04 - 94AL85000.

Doerry, Armin W.

2015-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "radar doppler spectra" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Discover the Benefits of Radar Imaging | Open Energy Information  

Open Energy Info (EERE)

Discover the Benefits of Radar Imaging Discover the Benefits of Radar Imaging Jump to: navigation, search OpenEI Reference LibraryAdd to library Web Site: Discover the Benefits of Radar Imaging Author William V. Parker Published EIJ Earth Imaging Journal, 2012 DOI Not Provided Check for DOI availability: http://crossref.org Online Internet link for Discover the Benefits of Radar Imaging Citation William V. Parker. Discover the Benefits of Radar Imaging [Internet]. 2012. N/A. EIJ Earth Imaging Journal. [updated 2013/09/20;cited 2013/09/20]. Available from: http://eijournal.com/2012/discover-the-benefits-of-radar-imaging GEOTHERMAL ENERGYGeothermal Home Web Site: Discover the Benefits of Radar imaging Details Abstract: Unavailable Author(s): William V. Parker Published: EIJ Earth Imaging Journal, 2012

202

Detection of electron velocity in graphene by Doppler effect  

Science Journals Connector (OSTI)

Abstract Electron velocity in a two-dimensional electron gas can be measured by Doppler shift. Thus, we construct the Doppler shift of light and apply it to the motion of electrons in a graphene sheet to estimate the electron velocity. Here, a laser beam with initial frequency is incident on the graphene sheet in a parallel direction, and then the frequency of the emitted light can be measured by spectroscopy after detecting the electron velocity. Then, the ratio of frequency shift from the Doppler effect is described in terms of the electron velocity, as well as the incident and the detection angle of laser beam. The thermal broadening of detected frequency as a function of velocity is also shown for different temperatures.

Heetae Kim; Chang-Soo Park; Hak Dong Cho

2014-01-01T23:59:59.000Z

203

Three-dimensional laser cooling at the Doppler limit  

E-Print Network [OSTI]

Many predictions of the theory of Doppler cooling of 2-level atoms, notably the celebrated minimum achievable temperature $T_D=\\hbar \\Gamma/2 k_B$, have never been verified in a three-dimensional geometry. Here, we show that, despite their degenerate level structure, we can use Helium-4 atoms to achieve a situation in which these predictions can be verified. We make measurements of atomic temperatures, magneto-optical trap sizes, and the sensitivity of optical molasses to a power imbalance in the laser beams, finding excellent agreement with the Doppler theory. We show that the special properties of Helium, particularly its small mass and narrow transition linewidth, prevent effective sub-Doppler cooling with red-detuned optical molasses.

Chang, Rockson; Bouton, Quentin; Fang, Yami; Klafka, Tobias; Audo, Kevin; Aspect, Alain; Westbrook, Christoph I; Clément, David

2014-01-01T23:59:59.000Z

204

Precision Measuring of Velocities via the Relativistic Doppler Effect  

E-Print Network [OSTI]

Just as the ordinary Doppler effect serves as a tool to measure radial velocities of celestial objects, so can the relativistic Doppler effect be implemented to measure a combination of radial and transverse velocities by using recent improvements in observing techniques. A key element that makes a further use of this combination feasible is the periodicity in changes of the orbital velocity direction for the source. Two cases are considered: (i) a binary star; and (ii) a solitary star with the planetary companion. It is shown that, in case (i), several precision Doppler measurements employing the gas absorption cell technique would determine both the total orbital velocity and the inclination angle of the binary orbit disentangled from the peculiar velocity of the system. The necessary condition for that is the measured, at least with a modest precision, proper motion and distance to the system.

Leonid M. Ozernoy

1997-12-26T23:59:59.000Z

205

Doppler-like effect and doubtful expansion of universe  

E-Print Network [OSTI]

The distance contraction, as observed in electrical soundings over horizontally stratified earth (static system), is identified as a counterpart of Doppler shift in dynamical systems. Identification of Doppler-like effect in a stock-still systems makes it possible to give an al-ternative answer to the question about an effective cause of the Doppler shift, which sounds: the inhomogeneities. This answer opens different static as well as kinematic possibilities, which challenge established theories of expanding universe and energizing big bang.The energy propagating in stratified universe of layers exhibits a shift which could be at-tributed not only to the expansion (Hubble's theory) but alternatively to fluctuations in material properties (inhomogeneities).

Edward Szaraniec

2003-10-01T23:59:59.000Z

206

An Atlas of Stellar Spectra  

E-Print Network [OSTI]

An Atlas of Stellar Spectra with an Outline of Spectral Classification ? W. W. Morgan Philip C University of California of the University of Chicago #12; An Atlas of Stellar Spectra with an Outline New York The Cambridge University Press London #12; AN ATLAS OF STELLAR SPECTRA With an Outline

Dworetsky, Mike

207

Anomalous Doppler effect observed during propagation of magnetostatic waves in ferromagnetic films and ferrite-dielectric-metal structures  

Science Journals Connector (OSTI)

The anomalous Doppler effect observed during propagation of magnetostatic backward volume ... ferrite-dielectric-metal structure is investigated. The effect is theoretically substantiated, and plots of Doppler fr...

Yu. A. Ignatov; A. A. Klimov; S. A. Nikitov

2010-04-01T23:59:59.000Z

208

Doppler Effect Associated with the Reflection of Light on a Moving Mirror  

E-Print Network [OSTI]

The Doppler Effect associated with the reflection on a moving mirror is reduced to two Doppler Effect experiments involving the incoming incident ray and the outgoing reflected ray or vice-versa. The dependence of the corresponding Doppler factors on the incidence angle on the stationary mirror.

Bernhard Rothenstein; Ioan Damian

2005-08-18T23:59:59.000Z

209

Doppler Ultrasound Driven Biomechanical Model of the Brain for  

E-Print Network [OSTI]

Doppler Ultrasound Driven Biomechanical Model of the Brain for Intraoperative Brain of the target is essential to reduce mor- bidity during brain tumor removal interventions. Yet, image-guided neu- rosurgery faces an important issue for large skull openings where brain soft-tissues can exhibit large

Paris-Sud XI, Université de

210

Dual beam translator for use in Laser Doppler anemometry  

DOE Patents [OSTI]

A method and apparatus for selectively translating the path of at least one pair of light beams in a Laser Doppler anemometry device whereby the light paths are translated in a direction parallel to the original beam paths so as to enable attainment of spacial coincidence of the two intersection volumes and permit accurate measurements of Reynolds shear stress.

Brudnoy, D.M.

1984-04-12T23:59:59.000Z

211

Generalized Doppler effect in spaces with a transport along paths  

E-Print Network [OSTI]

An analog of the classical Doppler effect is investigated in spaces (manifolds) whose tangent bundle is endowed with a transport along paths, which, in particular, can be parallel one. The obtained results are valid irrespectively to the particles mass, i.e. they hold for massless particles (e.g. photons) as well as for massive ones.

Bozhidar Z. Iliev

2004-01-19T23:59:59.000Z

212

Research on Fast-Doppler-Broadening of neutron cross sections  

SciTech Connect (OSTI)

A Fast-Doppler-Broadening method is developed in this work to broaden Continuous Energy neutron cross-sections for Monte Carlo calculations. Gauss integration algorithm and parallel computing are implemented in this method, which is unprecedented in the history of cross section processing. Compared to the traditional code (NJOY, SIGMA1, etc.), the new Fast-Doppler-Broadening method shows a remarkable speedup with keeping accuracy. The purpose of using Gauss integration is to avoid complex derivation of traditional broadening formula and heavy load of computing complementary error function that slows down the Doppler broadening process. The OpenMP environment is utilized in parallel computing which can take full advantage of modern multi-processor computers. Combination of the two can reduce processing time of main actinides (such as {sup 238}U, {sup 235}U) to an order of magnitude of 1{approx}2 seconds. This new method is fast enough to be applied to Online Doppler broadening. It can be combined or coupled with Monte Carlo transport code to solve temperature dependent problems and neutronics-thermal hydraulics coupled scheme which is a big challenge for the conventional NJOY-MCNP system. Examples are shown to determine the efficiency and relative errors compared with the NJOY results. A Godiva Benchmark is also used in order to test the ACE libraries produced by the new method. (authors)

Li, S.; Wang, K.; Yu, G. [Dept. of Engineering Physics, Tsinghua Univ., Beijing, 100084 (China)

2012-07-01T23:59:59.000Z

213

Complex Doppler effect in left-handed metamaterials  

E-Print Network [OSTI]

The Doppler shift is investigated in one-dimensional system with moving source. Theoretical findings are confirmed in numerical simulations of optical and acoustical waves propagation in simple metamaterial model, showing the reversed shift and the existence of multiple frequency modes. The properties of these waves are discussed. The effect of absorption on the phenomenon is outlined.

Ziemkiewicz, David

2014-01-01T23:59:59.000Z

214

Doppler optical mixing spectroscopy in multiparticle scattering fluids  

SciTech Connect (OSTI)

We discuss the basic scheme of laser Doppler optical mixing spectroscopy for the analysis of media with multiparticle scattering. It is shown that the Rayleigh scheme, in contrast to the heterodyne and differential schemes, is insensitive to the effects of multiparticle scattering. (laser applications and other aspects of quantum electronics)

Dubnishchev, Yu N [S S Kutateladze Institute of Thermophysics, Siberian Branch, Russian Academy of Sciences, Novosibirsk (Russian Federation)

2011-03-31T23:59:59.000Z

215

Doppler effect for an optical discharge source of shock waves  

SciTech Connect (OSTI)

The Doppler effect for a moving pulsating optical discharge producing periodic shock waves is considered. The manifestations of the effect are limited by the wave merging mechanism. The validity conditions were found for the effect in the case of a pulsating source of shock waves. (interaction of laser radiation with matter. laser plasma)

Tishchenko, V N [Institute of Laser Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk (Russian Federation)

2005-11-30T23:59:59.000Z

216

Synthetic Aperture Radar Persistent Scatterer Interferometry (PSInSAR) |  

Open Energy Info (EERE)

Synthetic Aperture Radar Persistent Scatterer Interferometry (PSInSAR) Synthetic Aperture Radar Persistent Scatterer Interferometry (PSInSAR) Jump to: navigation, search OpenEI Reference LibraryAdd to library Web Site: Synthetic Aperture Radar Persistent Scatterer Interferometry (PSInSAR) Author Parviz Tarikhi Published N/A, 2010 DOI Not Provided Check for DOI availability: http://crossref.org Online Internet link for Synthetic Aperture Radar Persistent Scatterer Interferometry (PSInSAR) Citation Parviz Tarikhi. Synthetic Aperture Radar Persistent Scatterer Interferometry (PSInSAR) [Internet]. 2010. Tunis, Tunisia. N/A. [cited 2013/09/17]. Available from: http://parviztarikhi.files.wordpress.com/2010/05/3psinsar-i-parviz_tarikhi.pdf Retrieved from "http://en.openei.org/w/index.php?title=Synthetic_Aperture_Radar_Persistent_Scatterer_Interferometry_(PSInSAR)&oldid=682949"

217

ARM - Field Campaign - 2001 Multi-Frequency Radar IOP  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

govCampaigns2001 Multi-Frequency Radar IOP govCampaigns2001 Multi-Frequency Radar IOP Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Campaign : 2001 Multi-Frequency Radar IOP 2001.03.01 - 2001.09.30 Lead Scientist : Stephen Sekelsky Data Availability http://abyss.ecs.umass.edu For data sets, see below. Summary Install UMass and NOAA Aeronomy Laboratory "guest instrument" radars at the SGP CART site adjacent to the MMCR system. Both the UMass and NOAA Aeronomy Laboratory systems will run autonomously for approximately a six month period. Description Scientific hypothesis: A. Measurements from the University of Massachusetts (UMass) Cloud Profiling Radar System (CPRS) - 95/33 GHz Radar indicate that the 95 GHz channel is much less sensitive to insect clutter than the 35 GHz channel by

218

Non-Gaussianity and CMB aberration and Doppler  

SciTech Connect (OSTI)

The peculiar motion of an observer with respect to the CMB rest frame induces a deflection in the arrival direction of the observed photons (also known as CMB aberration) and a Doppler shift in the measured photon frequencies. As a consequence, aberration and Doppler effects induce non trivial correlations between the harmonic coefficients of the observed CMB temperature maps. In this paper we investigate whether these correlations generate a bias on non-Gaussianity estimators f{sub NL}. We perform this analysis simulating a large number of temperature maps with Planck-like resolution (lmax = 2000) as different realizations of the same cosmological fiducial model (WMAP7yr). We then add to these maps aberration and Doppler effects employing a modified version of the HEALPix code. We finally evaluate a generalization of the Komatsu, Spergel and Wandelt non-Gaussianity estimator for all the simulated maps, both when peculiar velocity effects have been considered and when these phenomena have been neglected. Using the value v/c = 1.23 × 10{sup ?3} for our peculiar velocity, we found that the aberration/Doppler induced non-Gaussian signal is at most of about half of the cosmic variance ? for f{sub NL} both in a full-sky and in a cut-sky experimental configuration, for local, equilateral and orthogonal estimators. We conclude therefore that when estimating f{sub NL} it is safe to ignore aberration and Doppler effects if the primordial map is already Gaussian. More work is necessary however to assess whether a map which contains non-Gaussianity can be significantly distorted by a peculiar velocity.

Catena, Riccardo [Institut für Theoretische Physik, Friedrich-Hund-Platz 1, 37077 Göttingen (Germany); Liguori, Michele; Renzi, Alessandro [INFN, Sezione di Padova, Via Marzolo 8, 35131 Padova (Italy); Notari, Alessio, E-mail: riccardo.catena@theorie.physik.uni-goettingen.de, E-mail: michele.liguori@pd.infn.it, E-mail: notari@ffn.ub.es, E-mail: arenzi@pd.infn.it [Departament de Física Fondamental i Institut de Ciéncies del Cosmos, Universitat de Barcelona, Martí i Franqués 1, 08028 Barcelona (Spain)

2013-09-01T23:59:59.000Z

219

Mitigating Wind-Radar Interference | Department of Energy  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

mitigating radar interference caused by the physical and electromagnetic effects of wind turbines. These new mitigation technologies are expected to open up new areas to wind...

220

Sandia National Laboratories: Siting: Wind Turbine/Radar Interference...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

and MIT Lincoln Laboratory). The goal is to overcome interference caused by wind turbines on civilian and military radar systems by developing site planning tools,...

Note: This page contains sample records for the topic "radar doppler spectra" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

INTERAGENCY FIELD TEST & EVALUATION OF WIND TURBINE - RADAR INTERFEREN...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

the tests and 2) summaries of three field tests designed to measure the impact of wind turbines on current air surveillance radars and the effectiveness of private sector...

222

Modeling Of Surface Deformation From Satellite Radar Interferometry...  

Open Energy Info (EERE)

interferometric synthetic aperture radar) analysis of two-year Radarsat satellite data covering the period May 2006 - March 2008. SAR scenes from two orbit geometries are...

223

NNSA Completes its Critical Radar Arming and Fuzing Test for...  

National Nuclear Security Administration (NNSA)

its Critical Radar Arming and Fuzing Test for the W88 ALT 370 | National Nuclear Security Administration People Mission Managing the Stockpile Preventing Proliferation Powering the...

224

Statistical estimation and tracking of refractivity from radar clutter  

E-Print Network [OSTI]

Bahrain, Persian Gulf . . . . . . . . . . . . Table 4.2:boundary layer over the Persian gulf. Journal of Appliedsuface radar ducts over the Persian gulf. Journal of Applied

Yardim, Caglar

2007-01-01T23:59:59.000Z

225

Development and characterization analysis of a radar polarimeter  

E-Print Network [OSTI]

OF FIGURES FIGURE 2a 2b 3a 3b Sa 5b 10 12 13 14 The Typical Radar-to-Target Geometry. Block Diagram of Frequency Modulated Continuous Wave Radar System. Simplified Frequency Modulated-Continuous Wave Radar System. Block Diagram of a Pulse... 8-1 8-2 C-I C-2 C-3 Approximation Nethod for Focusing the Antenna Pair at Some Height h . Linear FM Pulse Compression . . Signal Characteristics of FM Pulse Radar System Frequency and Time Representation of the filter Response. The Block...

Bong, Soei Siang

2012-06-07T23:59:59.000Z

226

E-Print Network 3.0 - asteroid radar astronomy Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

radar astronomy Search Powered by Explorit Topic List Advanced Search Sample search results for: asteroid radar astronomy Page: << < 1 2 3 4 5 > >> 1 The Mechanics of Moving...

227

E-Print Network 3.0 - aperture radar processing Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

sensors (Ex. TM, IKONOS, ERS) 3. Synthetic Aperture Radar... ;SPOT Image 12;Haiti Earthquake 12; Synthetic Aperture Radar (SAR) is a method for developing high... , textural...

228

E-Print Network 3.0 - acoustic radar Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

because the NOA radar is polarimetric, vertical and horizontal components... the satellite measurements with land-based weather radars, and in turn, the ... Source:...

229

Multipoint photonic doppler velocimetry using optical lens elements  

SciTech Connect (OSTI)

A probe including a fisheye lens is disclosed to measure the velocity distribution of a moving surface along many lines of sight. Laser light, directed to the surface and then reflected back from the surface, is Doppler shifted by the moving surface, collected into fisheye lens, and then directed to detection equipment through optic fibers. The received light is mixed with reference laser light and using photonic Doppler velocimetry, a continuous time record of the surface movement is obtained. An array of single-mode optical fibers provides an optic signal to an index-matching lens and eventually to a fisheye lens. The fiber array flat polished and coupled to the index-matching lens using index-matching gel. Numerous fibers in a fiber array project numerous rays through the fisheye lens which in turn project many measurement points at numerous different locations to establish surface coverage over a hemispherical shape with very little crosstalk.

Frogget, Brent Copely; Romero, Vincent Todd

2014-04-29T23:59:59.000Z

230

Prospects for Doppler cooling of three-electronic-level molecules  

SciTech Connect (OSTI)

Analogous to the extension of laser cooling techniques from two-level to three-level atoms, Doppler cooling of molecules with an intermediate electronic state is considered. In particular, we use a rate-equation approach to simulate cooling of SiO{sup +}, in which population buildup in the intermediate state is prevented by its short lifetime. We determine that Doppler cooling of SiO{sup +} can be accomplished without optically repumping from the intermediate state, at the cost of causing undesirable parity flips and rotational diffusion. Since the necessary repumping would require a large number of continuous-wave lasers, optical pulse shaping of a femtosecond laser is proposed as an attractive alternative. Other candidate three-electron-level molecules are also discussed.

Nguyen, J. H. V.; Odom, B. [Department of Physics and Astronomy, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208 (United States)

2011-05-15T23:59:59.000Z

231

High-Frequency Skywave Radar Track of Tropical Storm Debra  

Science Journals Connector (OSTI)

Tropical Storm Debra was tracked over a 31 h period in the Gulf of Mexico using the Wide Aperture Research Facility (WARF) high-frequency (HF) skywave radar in California. In contrast to the first WARF skywave radar tracking experiment in which ...

Joseph W. Maresca Jr.; Christopher T. Carlson

1981-04-01T23:59:59.000Z

232

Radar Vehicle Detection Within Four Quadrant Gate Crossings  

E-Print Network [OSTI]

Vehicle Detection System for Four-Quadrant Gate Warning Systems and Blocked Crossing Detection. Washington. . . . . Radar Vehicle Detection Within Four Quadrant Gate Crossings Dylan Horne 2014 Global Level and delay but ultimately in loss of life. Radar Vehicle Detection Within Four Quadrant Gate Crossings #12

Illinois at Urbana-Champaign, University of

233

An analysis of radar estimated precipitation to rain gauge measurements  

E-Print Network [OSTI]

the surface. These levels included 1.0 1.5@ 2.0 @ 2.5 km, and 3.0 km. Radar precipitation estimates were calculated at each 1.4 2 level using Z = 30ORand Z = 25OR" . The precipitation amounts, as measured by both the gauges and the radar,were used...

Gleason, Byron Edward

1997-01-01T23:59:59.000Z

234

Detailed Observations of Wind Turbine Clutter with Scanning Weather Radars  

Science Journals Connector (OSTI)

The wind power industry has seen tremendous growth over the past decade and with it has come the need for clutter mitigation techniques for nearby radar systems. Wind turbines can impart upon these radars a unique type of interference that is not ...

B. M. Isom; R. D. Palmer; G. S. Secrest; R. D. Rhoton; D. Saxion; T. L. Allmon; J. Reed; T. Crum; R. Vogt

2009-05-01T23:59:59.000Z

235

Experimental investigation of velocity biasing in laser Doppler anemometry  

E-Print Network [OSTI]

Tech University; Chair of Advisory Commettee: Dr. Gerald L. Morrison The effects of several velocity bias reduction schemes were invest- igated using a 3-D laser Doppler anemometer and counter type (burst) signal processors. Amongst these schemes... was the McLaughlin Tiederman 3-D weighting factor, time between data weighting factor, equal time interval sampling and analogue instrumentation measurements. The ana- logue instrumentation measurements were obtained from the analogue frequency outputs...

Wiedner, Brian Gregory

1988-01-01T23:59:59.000Z

236

A Fisheye Lens as a Photonic Doppler Velocimetry Probe  

SciTech Connect (OSTI)

These presentation visuals report an instrument that, by use of a fish-eye lens, generates a beat signal using fiber mixing of unshifted light with Doppler-shifted light and measures the beat frequency. Ray trace diagrams are shown to illustrate advantages and disadvantages. The authors find their instrument has a long tracking distance, and large angle coverage. Index matching eases assembly, reduces return loss and flattens the field.

Frogget, B. C.

2012-08-16T23:59:59.000Z

237

Doppler effect and frequency-shift in optics  

E-Print Network [OSTI]

A critical review of frequency-shift phenomena a la Doppler effect is presented. The importance of Fermi's theory of 1932 is pointed out, and it is argued that there exists a gap in our understanding of this phenomena at a fundamental level. Alternative mechanism in terms of photon number oscillations is suggested for polarization changing experiments. The physical reality of single photon is revisited, and a possible experimental scheme to test the alternative mechanism is suggested.

S C Tiwari

2004-10-12T23:59:59.000Z

238

Michelson interferometer null may confirm transverse Doppler Effect  

E-Print Network [OSTI]

We analyze fringe formation within Michelson-like experiments as viewed by relativistic inertial observers. Our analysis differs from previous work because we include optical misalignment of the beamsplitter of the interferometer due to the anamorphic geometry of relativistic Lorentz contraction. We conclude that inertial frame equivalence of Michelson-like experiments provide verification of the transverse Doppler Effect and exclude any model incorporating the relativistic Lorentz contraction effect.

Woodruff, Robert A

2014-01-01T23:59:59.000Z

239

Radar and sonar probing of potash  

E-Print Network [OSTI]

system Determination of the sylvinite and halite acoustic velocities using sonar 50 56 Samples Velocity measurements 56 57 TABLE OF CONTENTS (CONTINUED) CHAPTER Page V PROBING RESEARCH CONDUCTED IN THE IMC K-2 POTASH MINE 62 Geology... sylvinite and halite test samples 26 7 Schematic diagram of the 250 kHz sonar system used to measure the one-way travel time through sylvinite and halite test samples 26 8 Map showing the location of the Foxtrot and Bravo radar stations in the Petromisa...

Lopez Aguilar, Luis Felipe

2012-06-07T23:59:59.000Z

240

Wide-open, high-resolution microwave/millimeter-wave Doppler frequency shift estimation using photonics technology  

E-Print Network [OSTI]

Today, wide-open, high-resolution Doppler frequency shift (DFS) estimation is essential for radar, microwave/millimeter-wave, and communication systems. Using photonics technology, an effective approach is proposed and experimentally demonstrated, providing a high-resolution and frequency-independent solution. In the approach consisting of two cascaded opto-electronic modulators, DFS between the transmitted microwave/ millimeter-wave signal and the received echo signal is mapped into a doubled spacing between two target optical sidebands. Subsequently, the DFS is then estimated through the spectrum analysis of a generated low-frequency electrical signal, with an improved resolution by a factor of 2. In experiments, DFSs from -90 to 90 KHz are successfully estimated for microwave/millimeter-wave signals at 10, 15, and 30 GHz, where estimation errors keep lower than +/- 5e-10 Hz. For radial velocity measurement, these results reveal a range from 0 to 900 m/s (0 to 450 m/s) and a resolution of 1e-11 m/s (5e-12 m...

Zou, Xihua; Lu, Bing; Pan, Wei; Yan, Lianshan; Shao, Liyang

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "radar doppler spectra" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

PATTERN: Advantages of High Resolution Weather Radar Networks [EVS Event]  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

PATTERN: Advantages of High Resolution Weather Radar Networks PATTERN: Advantages of High Resolution Weather Radar Networks September 30, 2013 Speaker: Dr. Katharina Lengfeld Meteorological Institute, University of Hamburg, Germany Date: Monday, September 30, 2013 Time: 11 am - 12 noon Location: Argonne National Laboratory TCS Building 240 Room 4301 Precipitation observations with radars operating in the X-band frequency range are essential for meeting present and future requirements for flood forecasting, water management, and other hydro-meteorological applications. Besides having higher resolution, these systems are cost-effective compared to S- or C-band radars because of smaller antenna size. Disadvantages of single X-band radars are the large influence of attenuation by liquid water and a relatively short range.

242

Properties of tropical convection observed by ARM millimeter-radars  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Properties of tropical convection observed by ARM millimeter-radars Properties of tropical convection observed by ARM millimeter-radars Haynes, John Colorado State University Stephens, Graeme Colorado State University Category: Cloud Properties The results of an analysis of tropical cloud systems observed from a variety of vertically pointing radar systems are described. In particular, observations taken during five years of operation of the ARM millimeter wavelength radar system (MMCR) at Manus Island in the Tropical West Pacific region are characterized into cloud classes according to the radar reflectivity structures of these cloud systems, associated rainfall, and surface radiative properties. These observations of cloud properties are composited with respect to various phases of the Madden Julian Oscillation, which is a dominant mode of variability at Manus Island. A method of better

243

W-Band ARM Cloud Radar - Specifications and Design  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

W-Band ARM Cloud Radar - Specifications and Design W-Band ARM Cloud Radar - Specifications and Design K. B. Widener Pacific Northwest National Laboratory Richland, Washington J. B. Mead ProSensing, Inc. Amherst, Massachusetts Abstract The Atmospheric Radiation Measurement (ARM) Program and ProSensing, Inc. have teamed to develop and deploy the W-band ARM Cloud Radar (WACR) at the SGP central facility. The WACR will be co- located with the ARM millimeter wave cloud radar (MMCR) with planned operation to begin in early 2005. This radar will complement the measurements of the MMCR and will aid in filtering out insect contamination in the data. In this poster we present the design goals, expected performance characteristics, and the detailed design for the WACR. Introduction The MMCR has been operating at the Southern Great Plains (SGP) site since 1998. It has proven to be

244

Inversion of synthetic aperture radar interferograms for sources of  

Open Energy Info (EERE)

Inversion of synthetic aperture radar interferograms for sources of Inversion of synthetic aperture radar interferograms for sources of production-related subsidence at the Dixie Valley geothermal field Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article: Inversion of synthetic aperture radar interferograms for sources of production-related subsidence at the Dixie Valley geothermal field Authors Bill Foxall and D. W. Vasco Published Journal Journal of Volcanology and Geothermal Research, 2008 DOI Not Provided Check for DOI availability: http://crossref.org Online Internet link for Inversion of synthetic aperture radar interferograms for sources of production-related subsidence at the Dixie Valley geothermal field Citation Bill Foxall,D. W. Vasco. 2008. Inversion of synthetic aperture radar interferograms for sources of production-related subsidence at the Dixie

245

Synthetic Aperture Radar Movie Gallery -- Sandia National Laboratories  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Synthetic Aperture Radar Movie Gallery Synthetic Aperture Radar Movie Gallery This gallery features movies of Sandia National Laboratories' synthetic aperture radar imagery of Albuquerque, New Mexico and Washington, DC. Sandia's Twin-Otter SAR produced these high-resolution stripmap images in real time. (Note: The movies below have been downsampled greatly to make them suitable for viewing on the world wide web. These movies are not recommended for modems of speeds less than 56 kbps due to their large file sizes.) Albuquerque, NM Area Movies Sandia National Laboratories' Twin-Otter SAR produced these Ku-Band 0.3 and 1.0 meter resolution images of Albuquerque, NM in real time. Synthetic aperture radar movie of west Gibson Blvd 0.3 meter airborne synthetic aperture radar movie from I-25 to Maxwell along Gibson Blvd. (Length: 30 seconds)

246

On the convergence of the phase gradient autofocus algorithm for synthetic aperture radar imaging  

SciTech Connect (OSTI)

Synthetic Aperture Radar (SAR) imaging is a class of coherent range and Doppler signal processing techniques applied to remote sensing. The aperture is synthesized by recording and processing coherent signals at known positions along the flight path. Demands for greater image resolution put an extreme burden on requirements for inertial measurement units that are used to maintain accurate pulse-to-pulse position information. The recently developed Phase Gradient Autofocus algorithm relieves this burden by taking a data-driven digital signal processing approach to estimating the range-invariant phase aberrations due to either uncompensated motions of the SAR platform or to atmospheric turbulence. Although the performance of this four-step algorithm has been demonstrated, its convergence has not been modeled mathematically. A new sensitivity study of algorithm performance is a necessary step towards this model. Insights that are significant to the application of this algorithm to both SAR and to other coherent imaging applications are developed. New details on algorithm implementation identify an easily avoided biased phase estimate. A new algorithm for defining support of the point spread function is proposed, which promises to reduce the number of iterations required even for rural scenes with low signal-to-clutter ratios.

Hicks, M.J.

1996-01-01T23:59:59.000Z

247

Synthetic aperture radar processing with tiered subapertures  

SciTech Connect (OSTI)

Synthetic Aperture Radar (SAR) is used to form images that are maps of radar reflectivity of some scene of interest, from range soundings taken over some spatial aperture. Additionally, the range soundings are typically synthesized from a sampled frequency aperture. Efficient processing of the collected data necessitates using efficient digital signal processing techniques such as vector multiplies and fast implementations of the Discrete Fourier Transform. Inherent in image formation algorithms that use these is a trade-off between the size of the scene that can be acceptably imaged, and the resolution with which the image can be made. These limits arise from migration errors and spatially variant phase errors, and different algorithms mitigate these to varying degrees. Two fairly successful algorithms for airborne SARs are Polar Format processing, and Overlapped Subaperture (OSA) processing. This report introduces and summarizes the analysis of generalized Tiered Subaperture (TSA) techniques that are a superset of both Polar Format processing and OSA processing. It is shown how tiers of subapertures in both azimuth and range can effectively mitigate both migration errors and spatially variant phase errors to allow virtually arbitrary scene sizes, even in a dynamic motion environment.

Doerry, A.W. [Sandia National Labs., Albuquerque, NM (United States). Synthetic Aperture Radar Dept.

1994-06-01T23:59:59.000Z

248

Phonon characteristics of high {Tc} superconductors from neutron Doppler broadening measurements  

SciTech Connect (OSTI)

Statistical information on the phonon frequency spectrum of materials can be measured by neutron transmission techniques if they contain nuclei with low energy resonances, narrow enough to be Doppler-broadened, in their neutron cross sections. The authors have carried out some measurements using this technique for materials of the lanthanum barium cuprate class, La{sub 2{minus}x}Ba{sub x}CuO{sub 4}. Two samples with slightly different concentrations of oxygen, one being superconductive, the other not, were examined. Pure lanthanum cuprate was also measured. Lanthanum, barium and copper all have relatively low energy narrow resonances. Thus it should be possible to detect differences in the phonons carried by different kinds of atom in the lattice. Neutron cross section measurements have been made with high energy resolution and statistical precision on the 59m flight path of LANSCE, the pulsed spallation neutron source at Los Alamos National Laboratory. Measurements on all three materials were made over a range of temperatures from 15K to 300K, with small steps through the critical temperature region near 27K. No significant changes in the mean phonon energy of the lanthanum atoms were observed near the critical temperature of the super-conducting material. It appears however that the mean phonon energy of lanthanum in the superconductor is considerably higher than that in the non-superconductors. The samples used in this series of experiments were too thin in barium and copper to determine anything significant about their phonon spectra.

Trela, W.J.; Kwei, G.H.; Lynn, J.E. [Los Alamos National Lab., NM (United States); Meggers, K. [Univ. of Kiel (Germany)

1994-12-01T23:59:59.000Z

249

Geomorphic Evaluation of Radar Imagery of Southeastern Panama and Northwestern Colombia  

E-Print Network [OSTI]

directly from radar imagery . • • • • . • • • . • • . • • Radar chips from the four major landform regions in Darien Province I Panama: plains, low hills I high hills, and mountains. • • • . • . • • . • . . . Comparison of radar imagery and topographic...-Derived Terrain Slope (a) Data for Darien Province I Panama - Plains. • • • • • • • • • • • • • • • • • • 132 Cumulative Frequency Curves of Radar-Derived Terrain Slope (a) Data for Darien Province I Panama - Low Hills. • . . • • • . . • • . . • • • . 133...

Lewis, Anthony J.

1971-02-01T23:59:59.000Z

250

Doppler tomography of the Little Homunculus: high-resolution spectra of [Fe II] 16 435 around Eta Carinae  

Science Journals Connector (OSTI)

......if the LH were too , Car's powerful stellar wind...relative velocity between Car's polar wind and the...motion gives where is Car's average mass-loss...becomes more difficult. The alternative scenario - where the LH...as 1940. 6.3 Kinetic energy and the 1890 outburst......

Nathan Smith

2005-03-11T23:59:59.000Z

251

E-Print Network 3.0 - abnormal doppler enteral Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

abnormal doppler enteral Page: << < 1 2 3 4 5 > >> 1 1317 September 2009, Hamburg, Germany Poster abstracts The relationship between abdominal circumference and Summary:...

252

E-Print Network 3.0 - abdominal mediante doppler Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

abdominal mediante doppler Page: << < 1 2 3 4 5 > >> 1 1317 September 2009, Hamburg, Germany Poster abstracts The relationship between abdominal circumference and Summary:...

253

Effect of speckles on the depth sensitivity of laser Doppler perfusion imaging  

Science Journals Connector (OSTI)

A theoretical model is presented and experimentally validated that allows the prediction of the effect of speckles on the depth sensitivity of laser Doppler perfusion imaging. It is...

Rajan, V; Varghese, B; van Leeuwen, T G; Steenbergen, W

2007-01-01T23:59:59.000Z

254

Effect of Doppler broadening on quantitative concentration measurements with degenerate four-wave mixing spectroscopy  

Science Journals Connector (OSTI)

The effect of Doppler broadening on degenerate four-wave mixing (DFWM) signal intensities in the regime of high pump and probe laser intensities is investigated theoretically. DFWM...

Reichardt, Thomas A; Lucht, Robert P

1996-01-01T23:59:59.000Z

255

Effect of Doppler broadening on gain in an open V-type inversionless lasing system  

Science Journals Connector (OSTI)

Our study shows that for the copropagating probing and driving fields, the gain without inversion doesn't monotonously decrease or increase with the increasement of Doppler width....

Fan, Xijun; Xu, Hui; Tian, Shufen; Tong, Dianmin

2004-01-01T23:59:59.000Z

256

Rotational Doppler-effect due to selective excitation of vector-vortex field in optical fiber  

Science Journals Connector (OSTI)

Experimental demonstration of rotational Doppler-effect due to direct and simultaneous excitation of orthogonal elliptically-polarized fundamental and vortex modes in a two-mode...

Inavalli, V V G Krishna; Viswanathan, Nirmal K

2011-01-01T23:59:59.000Z

257

E-Print Network 3.0 - acoustic doppler velocimeter Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

of Hawai'i at Manoa Collection: Engineering 7 Quantifying Turbulence for Tidal Power Applications Summary: against Acoustic Doppler Velocimeter (ADV) data at a point....

258

The use of composite radar photographs in synoptic weather analysis  

E-Print Network [OSTI]

/acts Heteorologp THH CSE Oy COHPOSZTH ueAH PauZOnueaS II ITIOPTZC II@XIII kIkLYS1$ Approved aa ro eryia aad coaraat bye Cha of Coiaeitres Head of Baparensnt The uss of radar see?her observations in analysis of w*nther charts is considered. Thats observations... (1) 9 199, 9 1CWP J. , 1999 ~pf 1 1 Pf l~lhte 1 t~aai- sis, Chicago, University of Chicaso press, p. L7. to demonstrate ?tat the eimu1tcueoue radar observations of a lar-e portion of e storm incorporated as a composite radar photograph of several...

Smith, G. D.

2012-06-07T23:59:59.000Z

259

Wide band stepped frequency ground penetrating radar  

DOE Patents [OSTI]

A wide band ground penetrating radar system (10) embodying a method wherein a series of radio frequency signals (60) is produced by a single radio frequency source (16) and provided to a transmit antenna (26) for transmission to a target (54) and reflection therefrom to a receive antenna (28). A phase modulator (18) modulates those portion of the radio frequency signals (62) to be transmitted and the reflected modulated signal (62) is combined in a mixer (34) with the original radio frequency signal (60) to produce a resultant signal (53) which is demodulated to produce a series of direct current voltage signals (66) the envelope of which forms a cosine wave shaped plot (68) which is processed by a Fast Fourier Transform unit 44 into frequency domain data (70) wherein the position of a preponderant frequency is indicative of distance to the target (54) and magnitude is indicative of the signature of the target (54).

Bashforth, Michael B. (Buellton, CA); Gardner, Duane (Santa Maria, CA); Patrick, Douglas (Santa Maria, CA); Lewallen, Tricia A. (Ventura, CA); Nammath, Sharyn R. (Santa Barbara, CA); Painter, Kelly D. (Goleta, CA); Vadnais, Kenneth G. (Alexandria, VA)

1996-01-01T23:59:59.000Z

260

Holographic laser Doppler imaging of pulsatile blood flow  

E-Print Network [OSTI]

We report on wide-field imaging of pulsatile motion induced by blood flow using heterodyne holographic interferometry on the thumb of a healthy volunteer, in real-time. Optical Doppler images were measured with green laser light by a frequency-shifted Mach-Zehnder interferometer in off-axis configuration. The recorded optical signal was linked to local instantaneous out-of-plane motion of the skin at velocities of a few hundreds of microns per second, and compared to blood pulse monitored by plethysmoraphy during an occlusion-reperfusion experiment.

Bencteux, Jeffrey; Kostas, Thomas; Bayat, Sam; Atlan, Michael

2015-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "radar doppler spectra" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

SIRHEN : a data reduction program for photonic Doppler velocimetry measurements.  

SciTech Connect (OSTI)

SIRHEN (Sandia InfraRed HEtrodyne aNalysis) is a program for reducing data from photonic Doppler velocimetry (PDV) measurements. SIRHEN uses the short-time Fourier transform method to extract velocity information. The program can be run in MATLAB (2008b or later) or as a Windows executable. This report describes the new Sandia InfraRed HEtrodyne aNalysis program (SIRHEN; pronounced 'siren') that has been developed for efficient and robust analysis of PDV data. The program was designed for easy use within Sandia's dynamic compression community.

Dolan, Daniel H., III; Ao, Tommy

2010-06-01T23:59:59.000Z

262

Effect of window reflections on photonic Doppler velocimetry measurements  

SciTech Connect (OSTI)

Photonic Doppler velocimetry (PDV) has rapidly become a standard diagnostic for measuring velocities in dynamic compression research. While free surface velocity measurements are fairly straightforward, complications occur when PDV is used to measure a dynamically loaded sample through a window. Fresnel reflections can severely affect the velocity and time resolution of PDV measurements, especially for low-velocity transients. Shock experiments of quartz compressed between two sapphire plates demonstrate how optical window reflections cause ringing in the extracted PDV velocity profile. Velocity ringing is significantly reduced by using either a wedge window or an antireflective coating.

Ao, T.; Dolan, D. H. [Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)

2011-02-15T23:59:59.000Z

263

Numerical computation of doppler-broadening in the resonance domain  

SciTech Connect (OSTI)

We have implemented an accurate and fast calculation of the Doppler-broadened kernel PT(E {yields} E') for neutron elastic scattering based on a gas model. An exponential cutoff which accounts for the asymptotic behavior of the error function helps limit the range of integration while eliminating difference effects. This allows for calculating a kernel library for {sup 238}U over a very fine energy grid covering the resonance range in only a few hours in a laptop. We give an example showing the impact of {sup 238}U elastic up-scattering on the values of self shielded cross sections. (authors)

Sanchez, R. [Commissariat a l'Energie Atomique et aux Energies Alternatives, Service d'Etudes de Reacteurs et de Mathematiques Appliquees, CEA DEN DM2S/SERMA, 91191 Gif-sur-Yvette cedex (France); Hewko, C. [Commissariat a l'Energie Atomique et aux Energies Alternatives, Service d'Etudes de Reacteurs et de Mathematiques Appliquees, CEA DEN DM2S/SERMA, 91191 Gif-sur-Yvette cedex (France); AREVA NP/PEPDD-F, Tour Areva, Place J. Millier, 92084 La Defense (France); Santandrea, S. [Commissariat a l'Energie Atomique et aux Energies Alternatives, Service d'Etudes de Reacteurs et de Mathematiques Appliquees, CEA DEN DM2S/SERMA, 91191 Gif-sur-Yvette cedex (France)

2013-07-01T23:59:59.000Z

264

Geometric Doppler Effect: Spin-Split Dispersion of Thermal Radiation  

Science Journals Connector (OSTI)

A geometric Doppler effect manifested by a spin-split dispersion relation of thermal radiation is observed. A spin-dependent dispersion splitting was obtained in a structure consisting of a coupled thermal antenna array. The effect is due to a spin-orbit interaction resulting from the dynamics of the surface waves propagating along the structure whose local anisotropy axis is rotated in space. The observation of the spin-symmetry breaking in thermal radiation may be utilized for manipulation of spontaneous or stimulated emission.

Nir Dahan; Yuri Gorodetski; Kobi Frischwasser; Vladimir Kleiner; Erez Hasman

2010-09-21T23:59:59.000Z

265

Doppler Effect in the Slow Neutron Resonance in Rhodium  

Science Journals Connector (OSTI)

The variation in transmission of a rhodium foil to 1.26-ev neutrons has been measured as a function of foil temperature using a crystal spectrometer. A change in transmission of approximately two percent per 100-degree temperature change has been observed over a temperature range from 120°K to 860°K. After correction for instrument resolution and Doppler effect, a peak cross section of 4850±200 barns results. Comparison has been made with the theory of Bethe and Placzek as extended by Lamb.

H. H. Landon

1954-06-01T23:59:59.000Z

266

Improved Prediction of the Doppler Effect in TRISO Fuel  

SciTech Connect (OSTI)

The Doppler feedback mechanism is a major contributor to the passive safety of gas-cooled, graphite-moderated High Temperature Reactors that use fuel based on TRISO particles. It follows that the correct prediction of the magnitude and time-dependence of this feedback effect is essential to the conduct of safety analyses for these reactors. Since the effect is directly dependent on the actual temperature reached by the fuel during transients, the underlying phenomena of heat transfer and temperature rise must be correctly predicted. This paper presents an improved model for the TRISO particle and its thermal behavior during transients. The improved approach incorporates an explicit TRISO heat conduction model to better quantify the time dependence of the temperature in the various layers of the TRISO particle, including its fuel central zone. There follows a better treatment of the Doppler Effect within said fuel zone. The new model is based on a 1-D analytic solution for composite media using the Green’s function technique. The modeling improvement takes advantage of some of the physical behavior of TRISO fuel under irradiation and includes a distinctive look at the physics of the neutronic Doppler Effect. The new methodology has been implemented within the coupled R-Z nodal diffusion code CYNOD-THERMIX. The new model has been applied to the analysis of earthquakes (presented in a companion paper). In this paper, the model is applied to the control rod ejection event, as specified in the OECD PBMR-400 benchmark, but with temperature dependent thermal properties. The results obtained for this transient using the enhanced code are a considerable improvement over the predictions of the original code. The incorporation of the enhanced model shows that the Doppler Effect plays a more significant role than predicted by the original unenhanced model based on the THERMIX homogenized fuel region model. The new model shows that the overall energy generation during the rod ejection transient is significantly lower than predicted by the unenhanced model. The fuel temperature reaches a slightly higher maximum, but at no time does it approach the nominal allowable TRISO fuel temperature. The analyses with the enhanced model also show that the reactor period during the cool down is larger than previously predicted with the homogenous fuel region model.

J. Ortensi; A.M. Ougouag

2009-05-01T23:59:59.000Z

267

Modeling Of Surface Deformation From Satellite Radar Interferometry In The  

Open Energy Info (EERE)

Modeling Of Surface Deformation From Satellite Radar Interferometry In The Modeling Of Surface Deformation From Satellite Radar Interferometry In The Salton Sea Geothermal Field, California Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Conference Paper: Modeling Of Surface Deformation From Satellite Radar Interferometry In The Salton Sea Geothermal Field, California Details Activities (1) Areas (1) Regions (0) Abstract: Surface deformation in the Salton Sea geothermal field is modeled using results from satellite radar interferometry, data from leveling surveys, and observations from the regional GPS network. The field is located in the Salton Trough, an active spreading center in southern California, which is traversed by the Brawley seismic zone. Deformation time series at thousands of points in the study area are obtained from a

268

Applications of Radar Interferometry to Detect Surface Deformation in  

Open Energy Info (EERE)

Applications of Radar Interferometry to Detect Surface Deformation in Applications of Radar Interferometry to Detect Surface Deformation in Geothermal Areas of Imperial Valley in Southern California Jump to: navigation, search OpenEI Reference LibraryAdd to library Conference Paper: Applications of Radar Interferometry to Detect Surface Deformation in Geothermal Areas of Imperial Valley in Southern California Abstract InSAR (interferometric synthetic aperture radar) is applied in Imperial Valley of southern California to detect and characterize surface deformation in existing geothermal fields, possible future geothermal developments, and around faults. The data used are from the Envisat satellite, collected over the period 2003-2010. The specific InSAR technique applied, SqueeSARTM, identifies permanent and distributed scatterers (PS and DS), which play the role of numerous benchmarks

269

Tornado Warning Decisions Using Phased Array Radar Data  

Science Journals Connector (OSTI)

The 2012 Phased Array Radar Innovative Sensing Experiment identified how rapidly scanned full-volumetric data captured known mesoscale processes and impacted tornado-warning lead time. Twelve forecasters from nine National Weather Service forecast ...

Pamela Heinselman; Daphne LaDue; Darrel M. Kingfield; Robert Hoffman

270

Sensitivity Enhancement System for Pulse Compression Weather Radar  

Science Journals Connector (OSTI)

The use of low-power solid state transmitters in weather radar to keep costs down requires pulse compression technique in order to maintain an adequate minimum detectable signal. However, wide-band pulse compression filters will partly reduce the ...

Cuong M. Nguyen; V. Chandrasekar

271

Earth curvature and atmospheric refraction effects on radar signal propagation.  

SciTech Connect (OSTI)

The earth isn't flat, and radar beams don't travel straight. This becomes more noticeable as range increases, particularly at shallow depression/grazing angles. This report explores models for characterizing this behavior.

Doerry, Armin Walter

2013-01-01T23:59:59.000Z

272

Merging Cloud and Precipitation Radar Data Provides a Better  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Merging Cloud and Precipitation Radar Data Provides a Better View of Tropical Rain Clouds For original submission and image(s), see ARM Research Highlights http:www.arm.gov...

273

Observations of Strong Surface Radar Ducts over the Persian Gulf  

Science Journals Connector (OSTI)

Ducting of microwave radiation is a common phenomenon over the oceans. The height and strength of the duct are controlling factors for radar propagation and must be determined accurately to assess propagation ranges. A surface evaporation duct ...

Ian M. Brooks; Andreas K. Goroch; David P. Rogers

1999-09-01T23:59:59.000Z

274

Influence of Microscale Turbulent Droplet Clustering on Radar Cloud Observations  

Science Journals Connector (OSTI)

This study investigates the influence of microscale turbulent clustering of cloud droplets on the radar reflectivity factor and proposes a new parameterization to account for it. A three-dimensional direct numerical simulation of particle-laden ...

Keigo Matsuda; Ryo Onishi; Masaaki Hirahara; Ryoichi Kurose; Keiko Takahashi; Satoru Komori

2014-10-01T23:59:59.000Z

275

Automatic Detection of Wind Turbine Clutter for Weather Radars  

Science Journals Connector (OSTI)

Wind turbines cause contamination of weather radar signals that is often detrimental and difficult to distinguish from cloud returns. Because the turbines are always at the same location, it would seem simple to identify where wind turbine ...

Kenta Hood; Sebastián Torres; Robert Palmer

2010-11-01T23:59:59.000Z

276

Quality Control of Weather Radar Data Using Polarimetric Variables  

Science Journals Connector (OSTI)

Because weather radar data are commonly employed in automated weather applications, it is necessary to censor nonmeteorological contaminants, such as bioscatter, instrument artifacts, and ground clutter, from the data. With the operational ...

Valliappa Lakshmanan; Christopher Karstens; John Krause; Lin Tang

2014-06-01T23:59:59.000Z

277

Doppler disc tomography applied to low mass AGN spin  

E-Print Network [OSTI]

Doppler tomography can provide a powerful means of determining black hole spin when our view to the central regions are revealed and obscured by optically thick orbiting material, and can provide an independent estimate that does not suffer as many degeneracies as traditional methods. For low mass AGN, time-dependent obscuration is expected to leave a signature in the changing spectrum of the disc emission which extends into the soft X-ray bandpass. We create a spectral model incorporating Doppler tomography and apply it to the case of the low mass (8$\\times$10$^{5}$ M$_{\\odot}$) AGN, RX J1301.9+2747 which shows unusual timing properties in the form of short-lived flares that we argue are best explained by the orbit of a window through an optically thick wind. Modelling the phase-resolved spectrum over the course of the highest data quality flare indicates a very low spin even when we relax our constraints. This is the lowest mass AGN for which a spin has been measured and the first via this technique. We not...

Middleton, Matthew

2014-01-01T23:59:59.000Z

278

Intrinsic physical properties and Doppler boosting effects in LSI+61303  

E-Print Network [OSTI]

Our aim is to show how variable Doppler boosting of an intrinsically variable jet can explain the long-term modulation of 1667 \\pm 8 days observed in the radio emission of LSI+61303. The physical scenario is that of a conical, magnetized plasma jet having a periodical (P1) increase of relativistic particles, Nrel, at a specific orbital phase, as predicted by accretion in the eccentric orbit of LSI+61303. Jet precession (P2) changes the angle, eta, between jet axis and line of sight, thereby inducing variable Doppler boosting. The problem is defined in spherical geometry, and the optical depth through the precessing jet is calculated by taking into account that the plasma is stratified along the jet axis. The synchrotron emission of such a jet was calculated and we fitted the resulting flux density Smodel(t) to the observed flux density obtained during a 6.5-year monitoring of LSI+61303 by the Green Bank radio interferometer. Our physical model for the system LSI+61303 is not only able to reproduce the long-te...

Massi, M

2014-01-01T23:59:59.000Z

279

Doppler effect on target tracking in wireless sensor networks  

Science Journals Connector (OSTI)

This paper presents a new detection algorithm and high speed/accuracy tracker for tracking ground targets in acoustic wireless sensor networks (WSNs). Our detection algorithm naturally accounts for the Doppler effect which is an important consideration for tracking higher-speed targets. This algorithm employs Kalman filtering (KF) with the weighted sensor position centroid being used as the target position measurement. The weighted centroid makes the tracker to be independent of the detection model and changes the tracker to be near optimal, at least within the detection parameters used in this study. Our approach contrasts with previous approaches that employ more sophisticated tracking algorithms with higher computational complexity and use a power law detection model. The power law detection model is valid only for low speed targets and is susceptible to mismatch with detection by the sensors in the field. Our tracking model also enables us to uniquely study various environmental effects on track accuracy, such as the Doppler effect, signal collision, signal delay, and different sampling time. Our WSN tracking model is shown to be highly accurate for a moving target in both linear and accelerated motions. The computing speed is estimated to be 50–100 times faster than the previous more sophisticated methods and track accuracy compares very favorably.

Youngwon Kim An; Seong-Moo Yoo; Changhyuk An; B. Earl Wells

2013-01-01T23:59:59.000Z

280

Impact of airborne Doppler wind lidar profiles on numerical simulations of a tropical cyclone  

E-Print Network [OSTI]

Click Here for Full Article Impact of airborne Doppler wind lidar profiles on numerical simulations Regional Campaign (TPARC) field experiment in 2008, an airborne Doppler wind lidar (DWL) was onboard the U measurements on the numerical simulation of Typhoon Nuri (2008) in its formation phase. With an advanced

Pu, Zhaoxia

Note: This page contains sample records for the topic "radar doppler spectra" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Detection of femoral artery occlusion from spectral density of Doppler signals using the artificial neural network  

Science Journals Connector (OSTI)

This research is concentrated on the diagnosis of occlusion disease through the analysis of femoral artery Doppler signals with the help of Artificial Neural Network (ANN). Doppler femoral artery signals belong to occlusion patient and healthy subjects ... Keywords: Artificial neural network, Autoregressive, Back propagation algorithm, Femoral artery occlusion, Welch

Sadik Kara; Semra Kemalo?lu; Ay?egül Güven

2005-11-01T23:59:59.000Z

282

Doppler effects in a left-handed material: a first-principle theoretical study  

E-Print Network [OSTI]

The Doppler effects for the reflected wave from a moving media are systemically analyzed in this paper. The theoretical formula for the Doppler shift in the left-handed material, which is described by Drude's dispersion model, is presented. This formula is examined by first-principles numerical experiments, which are in agreement with the theoretical results.

Sanshui Xiao; Min Qiu

2004-11-16T23:59:59.000Z

283

Effects of Tunable Data Compression on Geophysical Products Retrieved from Surface Radar Observations with Applications to Spaceborne Meteorological Radars  

Science Journals Connector (OSTI)

This paper presents results and analyses of applying an international space data compression standard to weather radar measurements that can easily span eight orders of magnitude and typically require a large storage capacity as well as ...

Philip M. Gabriel; Penshu Yeh; Si-Chee Tsay

2014-11-01T23:59:59.000Z

284

Collapse and revival of the Doppler-Rabi oscillations of a moving atom in a cavity  

SciTech Connect (OSTI)

Collapse and revival of the Doppler-Rabi oscillations of a two-level atom moving in a cavity electromagnetic field are analyzed. The coupled atom-field dynamics are predicted accurately by numerical calculation and approximately by using the stationary phase approximation combined with the Poisson summation formula. The collapse and revival patterns are shown to be qualitatively different in the cases of moving atom and atom at rest. In particular, quantum revivals of Doppler-Rabi oscillations occur with a period determined by the Doppler shift of the atomic transition frequency. This regime of Doppler-Rabi oscillations requires that the Rabi frequency and the Doppler shift satisfy the condition {omega}{sub R} << {omega}{sub D}. Under the inverse relation, the collapse- revival phenomenon generally does not occur. It is shown that even a small amount of atom-cavity detuning eliminates collapse-revival behavior. The analysis is performed for both coherent and thermal cavity fields.

Kozlovskii, A. V. [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation)], E-mail: kozlovsk@sci.lebedev.ru

2008-11-15T23:59:59.000Z

285

Effect of Shenmai Injection (?????) on ventricular diastolic function in patients with chronic heart failure: An assessment by tissue Doppler imaging  

Science Journals Connector (OSTI)

To assess the effect of Shenmai Injection (?????, ... with chronic heart failure (CHF) by tissue Doppler imaging (TDI).

Rong-guo Ma ???; Chun-xia Wang; Yin-hua Shen…

2010-04-01T23:59:59.000Z

286

Information theory and energy spectra  

Science Journals Connector (OSTI)

We examine the possibility of inferring energy spectra and their concomitant eigenstates on the basis of incomplete information concerning the system’s ground state. In addition, the possibility of considering, as prior information, the expectation values of a partially unknown Hamiltonian also is examined and shown to be feasible.

N. Canosa; R. Rossignoli; A. Plastino

1991-02-01T23:59:59.000Z

287

An Early Performance Evaluation of the NEXRAD Dual-Polarization Radar Rainfall Estimates for Urban Flood Applications  

Science Journals Connector (OSTI)

Dual-polarization radars are expected to provide better rainfall estimates than single-polarization radars because of their ability to characterize hydrometeor type. The goal of this study is to evaluate single- and dual-polarization radar ...

Luciana K. Cunha; James A. Smith; Mary Lynn Baeck; Witold F. Krajewski

2013-12-01T23:59:59.000Z

288

3D REGULARIZED VELOCITY FROM 3D DOPPLER RADIAL VELOCITY X. Chen, J.L. Barron, R.E. Mercer  

E-Print Network [OSTI]

3D REGULARIZED VELOCITY FROM 3D DOPPLER RADIAL VELOCITY X. Chen, J.L. Barron, R.E. Mercer Dept, Ontario, M3H 5T4 Paul.Joe@ec.gc.ca ABSTRACT The recent availability of sequences of 3D Doppler radial velocity datasets provides sufficient information to estimate the 3D velocity of Doppler storms. We present

Barron, John

289

PHYSICAL REVIEW E 84, 056408 (2011) Doppler measurement of implosion velocity in fast Z-pinch x-ray sources  

E-Print Network [OSTI]

black holes in galaxy merger remnants [5]. In the laboratory, the Doppler effect reveals rotation of Doppler effects in these K-shell lines thus provides unique information about the plasma motionPHYSICAL REVIEW E 84, 056408 (2011) Doppler measurement of implosion velocity in fast Z-pinch x

Starobinets, Alexander

290

Scanning ARM Cloud Radars Part I: Operational Sampling Strategies  

SciTech Connect (OSTI)

Probing clouds in three-dimensions has never been done with scanning millimeter-wavelength (cloud) radars in a continuous operating environment. The acquisition of scanning cloud radars by the Atmospheric Radiation Measurement (ARM) program and research institutions around the world generate the need for developing operational scan strategies for cloud radars. Here, the first generation of sampling strategies for the Scanning ARM Cloud Radars (SACRs) is discussed. These scan strategies are designed to address the scientific objectives of the ARM program, however, they introduce an initial framework for operational scanning cloud radars. While the weather community uses scan strategies that are based on a sequence of scans at constant elevations, the SACRs scan strategies are based on a sequence of scans at constant azimuth. This is attributed to the cloud properties that are vastly different for rain and snow shafts that are the primary target of precipitation radars. A “cloud surveillance” scan strategy is introduced (HS-RHI) based on a sequence of horizon-to-horizon Range Height Indicator (RHI) scans that sample the hemispherical sky (HS). The HS-RHI scan strategy is repeated every 30 min to provide a static view of the cloud conditions around the SACR location. Between HS-RHI scan strategies other scan strategies are introduced depending on the cloud conditions. The SACRs are pointing vertically in the case of measurable precipitation at the ground. The radar reflectivities are corrected for water vapor attenuation and non-meteorological detection are removed. A hydrometeor detection mask is introduced based on the difference of cloud and noise statistics is discussed.

Kollias, Pavlos; Bharadwaj, Nitin; Widener, Kevin B.; Jo, Ieng; Johnson, Karen

2014-03-01T23:59:59.000Z

291

Doppler-free Yb spectroscopy with the fluorescence spot technique  

SciTech Connect (OSTI)

We demonstrate a simple technique to measure the resonant frequency of the 398.9-nm {sup 1}S{sub 0}{leftrightarrow}{sup 1}P{sub 1} transition for the different Yb isotopes. The technique, which works by observing and aligning fluorescence spots, has enabled us to measure transition frequencies and isotope shifts with an accuracy of 60 MHz. We provide wavelength measurements for the transition that differ from previously published work. Our technique also allows for the determination of Doppler-shifted transition frequencies for photoionization experiments when the atomic beam and the laser beam are not perpendicular and furthermore allows us to determine the average velocity of the atoms along the direction of the atomic beam.

Nizamani, Altaf H.; McLoughlin, James J.; Hensinger, Winfried K. [Department of Physics and Astronomy, University of Sussex, Falmer, Brighton, East-Sussex, BN1 9QH (United Kingdom)

2010-10-15T23:59:59.000Z

292

Doppler Effect of Nonlinear Waves and Superspirals in Oscillatory Media  

Science Journals Connector (OSTI)

Nonlinear waves emitted from a moving source are studied. A meandering spiral in a reaction-diffusion medium provides an example in which waves originate from a source exhibiting a back-and-forth movement in a radial direction. The periodic motion of the source induces a Doppler effect that causes a modulation in wavelength and amplitude of the waves (“superspiral”). Using direct simulations as well as numerical nonlinear analysis within the complex Ginzburg-Landau equation, we show that waves subject to a convective Eckhaus instability can exhibit monotonic growth or decay as well as saturation of these modulations depending on the perturbation frequency. Our findings elucidate recent experimental observations concerning superspirals and their decay to spatiotemporal chaos.

Lutz Brusch; Alessandro Torcini; Markus Bär

2003-09-05T23:59:59.000Z

293

Doppler Effect of Nonlinear Waves and Superspirals in Oscillatory Media  

E-Print Network [OSTI]

Nonlinear waves emitted from a moving source are studied. A meandering spiral in a reaction-diffusion medium provides an example, where waves originate from a source exhibiting a back-and-forth movement in radial direction. The periodic motion of the source induces a Doppler effect that causes a modulation in wavelength and amplitude of the waves (``superspiral''). Using the complex Ginzburg-Landau equation, we show that waves subject to a convective Eckhaus instability can exhibit monotonous growth or decay as well as saturation of these modulations away from the source depending on the perturbation frequency. Our findings allow a consistent interpretation of recent experimental observations concerning superspirals and their decay to spatio-temporal chaos.

Lutz Brusch; Alessandro Torcini; Markus Baer

2003-02-12T23:59:59.000Z

294

Graphene based tunable fractal Hilbert curve array broadband radar absorbing screen for radar cross section reduction  

SciTech Connect (OSTI)

This paper proposes a new type of graphene based tunable radar absorbing screen. The absorbing screen consists of Hilbert curve metal strip array and chemical vapour deposition (CVD) graphene sheet. The graphene based screen is not only tunable when the chemical potential of the graphene changes, but also has broadband effective absorption. The absorption bandwidth is from 8.9GHz to 18.1GHz, ie., relative bandwidth of more than 68%, at chemical potential of 0eV, which is significantly wider than that if the graphene sheet had not been employed. As the chemical potential varies from 0 to 0.4eV, the central frequency of the screen can be tuned from 13.5GHz to 19.0GHz. In the proposed structure, Hilbert curve metal strip array was designed to provide multiple narrow band resonances, whereas the graphene sheet directly underneath the metal strip array provides tunability and averagely required surface resistance so to significantly extend the screen operation bandwidth by providing broadband impedance matching and absorption. In addition, the thickness of the screen has been optimized to achieve nearly the minimum thickness limitation for a nonmagnetic absorber. The working principle of this absorbing screen is studied in details, and performance under various incident angles is presented. This work extends applications of graphene into tunable microwave radar cross section (RCS) reduction applications.

Huang, Xianjun, E-mail: xianjun.huang@manchester.ac.uk [School of Electrical and Electronic Engineering, University of Manchester, Manchester M13 9PL (United Kingdom); College of Electronic Science and Engineering, National University of Defense Technology, Changsha 410073 (China); Hu, Zhirun [School of Electrical and Electronic Engineering, University of Manchester, Manchester M13 9PL (United Kingdom); Liu, Peiguo [College of Electronic Science and Engineering, National University of Defense Technology, Changsha 410073 (China)

2014-11-15T23:59:59.000Z

295

Wavelet Spectra of JACEE Events  

E-Print Network [OSTI]

Pseudo-rapidity distributions of two high multiplicity events Ca-C and Si-AgBr observed by the JACEE are analysed by the wavelet transform. Wavelet spectra of those events are calculated and compared with the simulation calculations. The wavelet spectrum of Ca-C event somewhat resembles to that simulated with the uniform random numbers. That of Si-AgBr event is not reproduced by simulation calculations with Poisson random numbers, uniform random numbers, or a p-model.

Naomichi Suzuki; Minoru Biyajima; Akinori Ohsawa

1995-03-22T23:59:59.000Z

296

Method and apparatus for ultrasonic doppler velocimetry using speed of sound and reflection mode pulsed wideband doppler  

DOE Patents [OSTI]

According to the present invention, a method and apparatus rely upon tomographic measurement of the speed of sound and fluid velocity in a pipe. The invention provides a more accurate profile of velocity within flow fields where the speed of sound varies within the cross-section of the pipe. This profile is obtained by reconstruction of the velocity profile from the local speed of sound measurement simultaneously with the flow velocity. The method of the present invention is real-time tomographic ultrasonic Doppler velocimetry utilizing a to plurality of ultrasonic transmission and reflection measurements along two orthogonal sets of parallel acoustic lines-of-sight. The fluid velocity profile and the acoustic velocity profile are determined by iteration between determining a fluid velocity profile and measuring local acoustic velocity until convergence is reached.

Shekarriz, Alireza (Kennewick, WA); Sheen, David M. (Richland, WA)

2000-01-01T23:59:59.000Z

297

Mesoscale Ocean Surface Current Structure Detected by High-Frequency Radar  

Science Journals Connector (OSTI)

The quality and vertical correlation scales of high-frequency (HF) radar-derived ocean surface current measurements from an ocean surface current radar (OSCR) are assessed by comparing surface to subsurface current observations from 11 June to 8 ...

Lynn K. Shay; Hans C. Graber; Duncan B. Ross; Rickey D. Chapman

1995-08-01T23:59:59.000Z

298

Simulation and detection of tsunami signatures in ocean surface currents measured by HF radar  

Science Journals Connector (OSTI)

High-frequency (HF) surface wave radars provide the unique capability to continuously monitor the coastal environment far beyond the range of conventional microwave radars. Bragg-resonant backscattering by ocean ...

Klaus-Werner Gurgel; Anna Dzvonkovskaya; Thomas Pohlmann; Thomas Schlick…

2011-10-01T23:59:59.000Z

299

E-Print Network 3.0 - aperture radar intensity Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

radar must have a large power-aperture product. Second, in order to obtain accurate wind velocities... arrays. The early radars could be pointed in only a few, Fig. 1. RHI...

300

E-Print Network 3.0 - advanced precipitation radar Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

2, 2730, 2008 www.adv-sci-res.net2272008 Summary: of precipitation data obtained from satellite and weather radar imagery requires validation with use of classic... radar and...

Note: This page contains sample records for the topic "radar doppler spectra" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

E-Print Network 3.0 - aperture radar 3d Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

would be inefficient to use the large aperture radar... PTGTGR 2 (dB) RadarFunction (dB) Weather Target Table 3. ... Source: Reuter, Martin - NMR Athinoula A. Martinos Center,...

302

A Radar-like Iron based Nanohybrid as an Efficient and Stable...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Radar-like Iron based Nanohybrid as an Efficient and Stable Electrocatalyst for Oxygen Reduction. A Radar-like Iron based Nanohybrid as an Efficient and Stable Electrocatalyst for...

303

E-Print Network 3.0 - airborne l-band radar Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Ecology 4 DELANEY AND WARD Radar Development at Lincoln Laboratory: An Overview of the First Fifty Years Summary: in a full-scale environment. The UHFL-band TRADEX radar shown in...

304

E-Print Network 3.0 - airborne radar sounding Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

3 DELANEY AND WARD Radar Development at Lincoln Laboratory: An Overview of the First Fifty Years Summary: , sea-based radars on ocean platforms called Texas Tow- ers, and...

305

Laser Doppler holographic microscopy in transmission: application to fish embryo imaging  

E-Print Network [OSTI]

We have extended Laser Doppler holographic microscopy to transmission geometry. The technique is validated with living fish embryos imaged by a modified upright bio-microcope. By varying the frequency of the holographic reference beam, and the combination of frames used to calculate the hologram, multimodal imaging has been performed. Doppler images of the blood vessels for different Doppler shifts, images where the flow direction is coded in RGB colors or movies showing blood cells individual motion have been obtained as well. The ability to select the Fourier space zone that is used to calculate the signal, makes the method quantitative.

Verrier, Nicolas; Gross, Michel

2014-01-01T23:59:59.000Z

306

Anomalous Doppler-Effect and Polariton-Mediated Cooling of Two-Level Atoms  

Science Journals Connector (OSTI)

We consider an atom moving in a near resonant laser field with its dipole strongly coupled to a resonator field mode. As compared to the standard Doppler shift, we find a substantially different and counterintuitive linear velocity dependence of the light scattering properties. The mechanical force of the laser field exhibits strong velocity selectivity at a polariton resonance, which gives rise to an enhanced friction force and Doppler cooling even in the directions perpendicular to the resonator axis. This effect allows for sub-Doppler cooling of atoms even with a nondegenerate ground state.

Peter Domokos; András Vukics; Helmut Ritsch

2004-03-11T23:59:59.000Z

307

Statistical maritime radar duct estimation using hybrid genetic algorithm-Markov chain Monte Carlo method  

E-Print Network [OSTI]

radar ducts over the Persian gulf,” Journal of Appliedas the Mediter- ranean, Persian Gulf, East China Sea, and

Yardim, Caglar; Gerstoft, Peter; Hodgkiss, William S.

2007-01-01T23:59:59.000Z

308

Time Correlations in Backscattering Radar Reflectivity Measurements from Cirrus Clouds  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Time Correlations in Backscattering Radar Reflectivity Time Correlations in Backscattering Radar Reflectivity Measurements from Cirrus Clouds K. Ivanova, H. N. Shirer, and E. E. Clothiaux Pennsylvania State University University Park, Pennsylvania T. P. Ackerman Pacific Northwest National Laboratory Richland, Washington Introduction The state variables of the atmosphere exhibit correlations at various spatial and temporal scales. These correlations are crucial for understanding short- and long-term trends in climate. Cirrus clouds are important phenomena in the troposphere affecting climate. To improve future parameterization of cirrus clouds in climate models, we must understand the cloud properties and how they change within the cloud. We consider fluctuations of cloud radar signals obtained at isodepths within cirrus clouds

309

Tracking moving radar targets with parallel, velocity-tuned filters  

DOE Patents [OSTI]

Radar data associated with radar illumination of a movable target is processed to monitor motion of the target. A plurality of filter operations are performed in parallel on the radar data so that each filter operation produces target image information. The filter operations are defined to have respectively corresponding velocity ranges that differ from one another. The target image information produced by one of the filter operations represents the target more accurately than the target image information produced by the remainder of the filter operations when a current velocity of the target is within the velocity range associated with the one filter operation. In response to the current velocity of the target being within the velocity range associated with the one filter operation, motion of the target is tracked based on the target image information produced by the one filter operation.

Bickel, Douglas L.; Harmony, David W.; Bielek, Timothy P.; Hollowell, Jeff A.; Murray, Margaret S.; Martinez, Ana

2013-04-30T23:59:59.000Z

310

R. Dagan et a1.: A complementary Doppler Broadening formalism and its impact on nuclear reactor simulation R. Dagan, B. Becker and Y Danon  

E-Print Network [OSTI]

simulation R. Dagan, B. Becker and Y Danon Acomplementary Doppler Broadening formalism and its impact

Danon, Yaron

311

Morphology, Intensity, and Rainfall Production of MJO Convection: Observations from DYNAMO Shipborne Radar and TRMM  

Science Journals Connector (OSTI)

This study uses DYNAMO shipborne (R/V Revelle) radar and TRMM Precipitation Radar (PR) datasets to investigate MJO-associated convective systems in specific organizational modes (MCS vs. sub-MCS, linear vs. non-linear). The Revelle radar sampled ...

Weixin Xu; Steven A. Rutledge

312

Guiding the designer: A radar diagram process for applications with multiple layers  

Science Journals Connector (OSTI)

......called the radar diagram process for multiple...that some of the material in Section 3...or skills for handling controls to regulate...them. A radar diagram was created based...editing and image handling has a continuous...in the radar diagram, which indicated...medium skilled in handling PhotoShop Elements......

Linn Gustavsson Christiernin

2010-03-01T23:59:59.000Z

313

Receiver Antenna Array for a Multichannel Sense-and-Avoid Radar for Small UAVs  

E-Print Network [OSTI]

Receiver Antenna Array for a Multichannel Sense-and-Avoid Radar for Small UAVs Jose Francisco for use in a sense-and-avoid radar for use in the Cessna C-172 and small Unmanned Aerial Vehicles (UAVs. . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . ..10 1.1.1 Multichannel Sense-and-Avoid Radar for UAVs. . . . . . . . . . . . . . . . . . . . . . ...10

Kansas, University of

314

Streamflow Forecasting Based on Statistical Applications and Measurements Made with Rain Gage and Weather Radar  

E-Print Network [OSTI]

measurements taken with weather radar. In addition, accurate estimates of lag time can be made from radar observations. For a storm which is unevenly distributed over the watershed, it is demonstrated that a better estimation of lag time may be made from radar...

Hudlow, M.D.

315

Applying petrophysical models to radar travel time and electrical resistivity tomograms: Resolution-dependent limitations  

E-Print Network [OSTI]

Applying petrophysical models to radar travel time and electrical resistivity tomograms: Resolution the utility of radar travel time tomography (RTT) and electrical-resistivity tomography (ERT) for estimating to radar travel time and electrical resistivity tomograms: Resolution-dependent limitations, J. Geophys

Singha, Kamini

316

OTGsim: Simulation of an Off-the-Grid Radar Network with High Sensing Energy Cost  

E-Print Network [OSTI]

OTGsim: Simulation of an Off-the-Grid Radar Network with High Sensing Energy Cost Brian C. Donovan|kurose@cs.umass.edu Abstract--Many sensor network studies assume that the energy cost for sensing is negligible compared sensors with a high energy cost such as radar. For a node utilizing radar as its primary sensor

Kurose, Jim

317

Tornado identification from analyses of digital radar data  

E-Print Network [OSTI]

of Yukon, 40 km north- west of NSSL. Later, a cell to the northwest of Oklahoma City developed to str'ong intensity and a funnel cloud was reported over Tinker AFB at 1930 CST. Hist~or of the Yukon Storm During the afternoon, the squall line moved... signature 1n analyses of digital radar data from ceni;ra 1 Oklahoma during the Spring. The data were collected by the l0-cm WSR-57 radar at the National Severe S torms Laboratory at Ilorman, Oklahoma. Three types of numerical analyses were used in th1s...

Pittman, Donald Wayne

2012-06-07T23:59:59.000Z

318

E-Print Network 3.0 - airborne pulse doppler Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

pulse doppler Page: << < 1 2 3 4 5 > >> 1 JOINT DOMAIN LOCALIZEDPROCESSINGUSING MEASURED SPATIAL STEERINGVECTORS* Summary: by f , d sin OIL, f,2vLYdlPRF,where PRF is the pulse...

319

Effect of Dobutamine on a Doppler Echocardiographic Index of Combined Systolic and Diastolic Performance  

Science Journals Connector (OSTI)

Dobutamine stress echocardiography has become accepted in the evaluation of cardiac functional reserve. Although the Doppler-derived index of combined systolic/diastolic myocardial ... useful for predicting left ...

K. Harada; M. Tamura; M. Toyono; K. Yasuoka

2002-12-01T23:59:59.000Z

320

Effect of microbubble contrast on intracranial blood flow velocity assessed by transcranial Doppler  

Science Journals Connector (OSTI)

Ultrasound contrast agents (UCA) salvage a considerable number of transcranial Doppler (TCD) exams which would have failed ... measured blood flow velocity (BFV). The effect of UCA continuous infusion on measured...

Nicola Logallo; Annette Fromm; Ulrike Waje-Andreassen…

2014-03-01T23:59:59.000Z

Note: This page contains sample records for the topic "radar doppler spectra" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Doppler effects of a light source on a metamaterial slab: a rigorous Green's function approach  

Science Journals Connector (OSTI)

We apply a (rigorous) Green's function theory to study the Doppler effects of a light source placed on top of a metamaterial slab. When the receiver is in motion with the source and...

Wang, Weihua; Huang, Xueqin; Zhou, Lei; Chan, C T

2008-01-01T23:59:59.000Z

322

On the doppler effect and universal fields: an answer to Wilczy?ski  

Science Journals Connector (OSTI)

Wilczy?ski’s criticism of our derivation of the “relativistic” Doppler formula is repudiated. Some clarifications intended to facilitate the understanding are made. The main points of the aether approach are s...

M. F. Podlaha; T. Sjödin

1984-12-01T23:59:59.000Z

323

Effect of respiration on Doppler parameters of normal tricuspid porcine bioprosthetic valves  

Science Journals Connector (OSTI)

The Doppler indexes of tricuspid porcine bioprosthetic valves were evaluated in twelve patients without clinical and two-dimensional echocardiographic evidence of valve dysfunction. Peak and mean pressure grad...

Bernard Cosyns; Guy van Camp; Alain Friart…

1995-03-01T23:59:59.000Z

324

The Doppler Effect and Form of the Profile of Radiation Spectral Lines  

Science Journals Connector (OSTI)

The form of the profile for spectral lines of radiation is found using the relativistic distribution function (DF) of fluxons on velocities and exact relativistic Doppler formula for frequencies. It is shown t...

M. R. Djumaev

2001-01-01T23:59:59.000Z

325

Taking aberrations into account in experiments testing the relativistic theory of the Doppler effect  

Science Journals Connector (OSTI)

The interpretation of experimental results [L. A. Pobedonostsev, Sov. Phys. Tech. Phys. 34..., 303 (1989)] on a test of the relativistic formula for the Doppler effect and the mistaken conclusion drawn by one...6

V. O. Beklyamishev

1999-02-01T23:59:59.000Z

326

Effect of renal Doppler ultrasound on the detection of nutcracker syndrome in children with hematuria  

Science Journals Connector (OSTI)

To assess the detection rate of nutcracker syndrome in children with isolated hematuria, renal Doppler ultrasound examinations were routinely performed on 216 ... microscopic hematuria and 40 gross hematuria). Re...

Jae Il Shin; Jee Min Park; Jae Seung Lee; Myung Joon Kim

2007-05-01T23:59:59.000Z

327

Unusual Doppler effect in superfluid and nonanalyticity of4He-3He hydrodynamics  

Science Journals Connector (OSTI)

We investigate the influence of3He admixture on the Doppler shift of different sounds in superfluid4He with internal motion. This influence proves to be very strong in the whole region of the nontrivial temperatu...

Y. A. Nepomnyashchy; N. Gov; A. Mann; M. Revzen

1995-08-01T23:59:59.000Z

328

Effect of net surface charge on particle sizing and material recognition by using phase Doppler anemometry  

Science Journals Connector (OSTI)

By taking net surface charge into consideration, the scattering field of particles illuminated by dual laser beams of phase Doppler anemometry (PDA) is computed based on Mie’s...

Zhou, Jun; Xie, Li

2011-01-01T23:59:59.000Z

329

Effect of wall scattering on SNR in off-axis differential-type laser Doppler velocimetry  

Science Journals Connector (OSTI)

Though various properties and applications of laser Doppler velocimetry have been extensively studied in the ... decade, there is little discussion on the effect of light scattering from the surface of a cell on

Hiromichi Mishina; Kazuo Takahashi; Toshimitsu Asakura

1983-09-01T23:59:59.000Z

330

Development of All-fiber Coherent Doppler Lidar to Measure Atmosphere Wind Speed  

Science Journals Connector (OSTI)

An all-fiber pulsed coherent Doppler lidar is developed to measure wind profiles. The maximum horizontal and vertical range for wind speed is 4.2km and 2km with speed accuracy of...

Liu, Jiqiao; Chen, Weibiao; Zhu, Xiaopeng

331

THE HUYGENS DOPPLER WIND EXPERIMENT Titan Winds Derived from Probe Radio Frequency Measurements  

E-Print Network [OSTI]

Doppler calibrations conducted with simulated Huygens signals uplinked from ground (Probe Relay Tests to the longer free-space propagation distance. Specific secondary science objectives of DWE include measurements

332

Improved real-time method for noise reduction of directional Doppler audio signals  

Science Journals Connector (OSTI)

A noise reduction filter for Doppler audio signals is one important part of Transcranial Doppler ultrasound system. Several studies have been carried out for low-pass filter with fixed value for Doppler audio signals; however, most of these studies lacked complex research works and few studies analyzed the relationship of both parts of spectrum signal processing and audio signal processing. To solve the above-mentioned concern, this research is focused on the algorithms of de-noising and enveloping of spectrum signal processing part and improved new real-time method, which reduces the noise using low-pass filter with a variable threshold value based on maximum frequency of spectrum signals. The noise of Doppler audio signals was reduced efficiently by using this algorithm.

Erdenedalai Naranchimeg; Byambasuren Bat-Erdene; Seung-Moo Han

2012-01-01T23:59:59.000Z

333

Modification of the Doppler Effect due to the Helicity-Rotation Coupling  

E-Print Network [OSTI]

The helicity-rotation coupling and its current empirical basis are examined. The modification of the Doppler effect due to the coupling of photon spin with the rotation of the observer is considered in detail in connection with its applications in the Doppler tracking of spacecraft. Further implications of this coupling and the possibility of searching for it in the intensity response of a rotating detector are briefly discussed.

Bahram Mashhoon

2002-09-22T23:59:59.000Z

334

Doppler Boosting and Deboosting Effects in the Forward Relativistic Jets of AGNs and GRBs  

E-Print Network [OSTI]

It is widely accepted that the Doppler deboosting effects exist in counter relativistic jets. However, people often neglect another important fact that both Doppler boosting and deboosting effects could happen in forward relativistic jets. Such effects might be used to explain some strange phenomena, such as the invisible gaps between the inner and outer jets of AGNs, and the rapid initial decays and re-brightening bumps in the light curves of GRBs.

Jianfeng Zhou; Yan Su

2006-10-15T23:59:59.000Z

335

Raman Spectra of Polyatomic Gases  

Science Journals Connector (OSTI)

Raman spectra of gaseous CO2, N2O, NH3, CH4 and C2H4 have been photographed using the line ?2536 of mercury as the exciting radiation. Vibrational transitions have been observed in all the gases investigated, and rotational transitions in the cases of NH3 and CH4. For the frequency shifts due to the vibrational transitions, the following numerical values (in cm-1) have been found: CO2: 1264.5; 1285.1; 1387.7; 1408.4.CH4: 2914.8; 3022.1; 3071.5.N2O: 1281.8C2H4: 1342.4; 1623.3; 2880.1; 3019.3; 3240.3; 3272.3.NH3: 3333.6  Raman spectra of liquid NH3 have been photographed and found to give the two frequency shifts: 3298.4 and 3214.5. In the case of gaseous NH3, pure rotational transitions lead to a moment of inertia having the value I0=2.79×10-40. In the case of methane, the positive and negative branches of the 3022.1 band lead to the value I0=5.17×10-40. The relations between these data and infra-red absorption data are discussed.

R. G. Dickinson, R. T. Dillon, and F. Rasetti

1929-08-15T23:59:59.000Z

336

Aircraft tracking by means of the Acoustical Doppler Effect  

Science Journals Connector (OSTI)

The present paper presents a passive acoustic method for aircraft tracking. The Acoustical Doppler Effect, characteristic of signals received by a mesh of spatially distributed microphones is the basis of the method. A one-dimensional version of the Ambiguity function permits the calculation of the frequency stretch factor that exists between the sound signals received by a pair of microphones. The expression for this frequency stretch is a function of the aircraft position and velocity which are estimated by a Genetic Algorithm. The method is suitable for all kinds of aircraft and requires only seven microphones plus the prior knowledge of only the aircraft position and velocity at a given time. Results are given for a simulation test of a 3D straight trajectory of the aircraft and for a sound-propagation model which considers geometrical spreading and atmospheric absorption of sound for a homogeneous medium. The influence of the atmospheric absorption is evaluated and the independence of the method with respect to microphone distribution is proven. The performance of the tracking method has also been evaluated in front of possible inaccuracy on the microphones synchronization.

Sara R. Martín; Meritxell Genescà; Jordi Romeu; Teresa Pàmies

2013-01-01T23:59:59.000Z

337

Effect of scattered radiation on sub-Doppler cooling  

Science Journals Connector (OSTI)

In this paper we discuss the effect of scattered radiation generated by a gas of cold atoms on the temperature of the gas. We show that by treating the reradiated field of the atoms as a fluctuating background field we can derive a master equation for a single atom where the effect of the surrounding medium is included in an effective relaxation operator. This relaxation operator is of second order in the interaction with the medium and in the binary-collision approximation can be written as the sum of two-body interactions with a correlation time equal to the natural lifetime of the atomic transition. The effect of the medium on the two most important sub-Doppler cooling mechanisms, Sisyphus and motion-induced orientation cooling, is investigated analytically in a one-dimensional model. In this we restrict ourselves to the limit of low saturation, weak background field and take the rate-equation limit for the collision operator. We find that both mechanisms are very sensitive to such a background field and that the temperature increases approximately as the number of atoms to the one-third power.

G. Hillenbrand; K. Burnett; C. J. Foot

1995-12-01T23:59:59.000Z

338

Reflectivity-Rain Rate Relationships for Radar Hydrology in Brazil  

Science Journals Connector (OSTI)

In this work a method is presented to obtain R-Z? relationships through comparison, in probability, of nonsimultaneous measurements of Z? and R. Range dependent relationships obtained in this way are given for a radar situated at 20°21?30?S, 49°...

R. V. Calheiros; I. Zawadzki

1987-01-01T23:59:59.000Z

339

2003 Mercury Computer Systems, Inc. Beamforming for Radar  

E-Print Network [OSTI]

© 2003 Mercury Computer Systems, Inc. Beamforming for Radar Systems on COTS Heterogeneous ComputingHeterogeneous Computing PlatformsPlatforms Jeffrey A. Rudin Mercury Computer Systems, Inc. High Performance Embedded Computing (HPEC) Conference September 23, 2003 #12;2© 2003 Mercury Computer Systems, Inc. Outline

Kepner, Jeremy

340

Improving Lightning Cessation Guidance Using Polarimetric Radar Data  

Science Journals Connector (OSTI)

Polarimetric radar data are used to develop lightning cessation guidance for the Cape Canaveral area of central Florida. Eighty non-severe thunderstorm cells in 2012, mostly during the warm season, are analyzed for this purpose. In-cloud and cloud-...

Ari D. Preston; Henry E. Fuelberg

Note: This page contains sample records for the topic "radar doppler spectra" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

High-Frequency Radar Mapping of Surface Currents Using WERA  

Science Journals Connector (OSTI)

A dual-station high-frequency Wellen Radar (WERA), transmitting at 16.045 MHz, was deployed along the west Florida shelf in phased array mode during the summer of 2003. A 33-day, continuous time series of radial and vector surface current fields ...

Lynn K. Shay; Jorge Martinez-Pedraja; Thomas M. Cook; Brian K. Haus; Robert H. Weisberg

2007-03-01T23:59:59.000Z

342

Development and Improvement of Airborne Remote Sensing Radar Platforms  

E-Print Network [OSTI]

, and several structures are also developed to enable a NASA P-3 to support a 15-element MCoRDS array, as well as three other radar antenna-arrays used for cryospheric surveying. Together, these aircraft have flown almost 200 missions and collected 550 TB...

Arnold, Emily J.

2013-08-31T23:59:59.000Z

343

CHARACTERIZATION OF A COOPERATIVE TARGET FOR GROUND-PENETRATING RADAR  

E-Print Network [OSTI]

Irving Hill Road, Lawrence KS 66045, USA callen@eecs.ukans.edu ABSTRACT A cooperative target (CT) has-made obstacles (utility lines, pipelines, vaults, etc.) enables the equipment operator and route planner signal level by enhancing its radar cross sec- tion (RCS). To do this we could introduce a large me

Kansas, University of

344

Winter Precipitation Microphysics Characterized by Polarimetric Radar and Video Disdrometer  

E-Print Network [OSTI]

are dependent on the type of precipitation that reaches the surface. Winter storms such as freezing rain precipitation not having the mixed phase. There are also some studies that focus on various winter precipitation types. Trapp et al (2001) used a polarimetric radar to observe a winter storm event with snow and mixed-phase

Droegemeier, Kelvin K.

345

WIDEBAND COPLANAR PATCH-SLOT ANTENNAS FOR RADAR APPLICATIONS  

E-Print Network [OSTI]

WIDEBAND COPLANAR PATCH-SLOT ANTENNAS FOR RADAR APPLICATIONS Atef Z. ElsherhenP, Abdelnasser A of coplanar patch antennas (CPA), designed to operate at a center frequency of.10 GHz with very wideband characteristics. The antenna is based on a rectangular patch surrounded by thin slot. and its performance is tuned

Elsherbeni, Atef Z.

346

Application of Electromagnetic (EM): Radar Salah M. Al-Ofi  

E-Print Network [OSTI]

physical properties such as direction, speed, distance or altitude of stationary or moving object e crew. Despite the failure of "death ray" development, The Brit- ish developers carried on their tests the atomic bomb [2]. III. PRINCIPLE OF WORK The main concept of radar relays on ECHO PRINCIPLE

Masoudi, Husain M.

347

Coherent radar ice thickness measurements over the Greenland ice sheet  

E-Print Network [OSTI]

systems are designed to use pulse compression techniques and coherent integration to obtain the high sensitivity required to measure the thickness of more than 4 km of cold ice. We used these systems to collect radar data over the interior and margins...

Gogineni, S. Prasad; Tammana, Dilip; Braaten, David A.; Leuschen, C.; Legarsky, J.; Kanagaratnam, P.; Stiles, J.; Allen, C.; Jezek, K.; Akins, T.

2001-12-27T23:59:59.000Z

348

TIDAL TURBULENCE SPECTRA FROM A COMPLIANT MOORING  

SciTech Connect (OSTI)

A compliant mooring to collect high frequency turbulence data at a tidal energy site is evaluated in a series of short demon- stration deployments. The Tidal Turbulence Mooring (TTM) improves upon recent bottom-mounted approaches by suspend- ing Acoustic Doppler Velocimeters (ADVs) at mid-water depths (which are more relevant to tidal turbines). The ADV turbulence data are superior to Acoustic Doppler Current Profiler (ADCP) data, but are subject to motion contamination when suspended on a mooring in strong currents. In this demonstration, passive stabilization is shown to be sufficient for acquiring bulk statistics of the turbulence, without motion correction. With motion cor- rection (post-processing), data quality is further improved; the relative merits of direct and spectral motion correction are dis- cussed.

Thomson, Jim; Kilcher, Levi; Richmond, Marshall C.; Talbert, Joe; deKlerk, Alex; Polagye, Brian; Guerra, Maricarmen; Cienfuegos, Rodrigo

2013-06-13T23:59:59.000Z

349

Spin conversion of positronium in NiO/Al2O3 catalysts observed by coincidence Doppler broadening technique  

Science Journals Connector (OSTI)

High-purity NiO/Al2O3 catalysts were prepared by mixing NiO and ?-Al2O3 nanopowders. X-ray diffraction patterns were measured to characterize the grain size and crystalline phase of the nanopowders. Positron-annihilation spectroscopy was used to study the microstructure and surface properties of the pores inside the NiO/Al2O3 catalysts. The positron lifetime spectrum comprises two short and two long lifetime components. The two long lifetimes ?3 and ?4 correspond to ortho-positronium (o-Ps) annihilated in microvoids and large pores, respectively. With increasing NiO content in the NiO/Al2O3 catalysts, both ?4 and its intensity I4 show continuous decrease. Meanwhile, the para-positronium (p-Ps) intensity, obtained from coincidence Doppler broadening spectra, increases gradually with NiO content. The different variation in o-Ps and p-Ps intensity suggests the ortho-para conversion of positronium in NiO/Al2O3 catalysts. X-ray photoelectron spectroscopy shows that Ni mainly exists in the form of NiO. The electron-spin-resonance measurements reveal that the ortho-para conversion of Ps is induced by the unpaired electrons of the paramagnetic centers of NiO.

H. J. Zhang; Z. Q. Chen; S. J. Wang; A. Kawasuso; N. Morishita

2010-07-28T23:59:59.000Z

350

Microsoft PowerPoint - arm_stm07-poster_matrosov.ppt  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

retrievals using mm-wavelength cloud radar measurements retrievals using mm-wavelength cloud radar measurements Sergey Y. Matrosov, Matthew D. Shupe Cooperative Institute for Research in Environmental Sciences, University of Colorado and NOAA Environmental Technology Laboratory Purpose: Extending ARM column hydrometeor retrievals to include solid precipitation cases Approach: Z e -S relations customized for the use with mm- wavelength radars. Using the Doppler information (moments and spectra) for quantitative retrievals in snowfall is limited because snowflake fall velocities do not exhibit clear size dependence ( for D>2 mm or so).The Doppler information, however, provides valuable qualitative information on degree of snowflake riming thus separating "dry" snowfall from cases with substantial

351

A Cold Frontal Rainband Observed during the LANDES-FRONTS 84 Experiment: Mesoscale and Small-Scale Structure Inferred from Dual-Doppler Radar Analysis.  

Science Journals Connector (OSTI)

This paper presents the kinematic structure of a cold frontal rainband associated with a secondary cold front which moved over southwest of France on 4 June 1984.

Y. Lemaitre; G. Scialom; P. Amayenc

1989-07-01T23:59:59.000Z

352

EnKF Assimilation of High-Resolution, Mobile Doppler Radar Data of the 4 May 2007 Greensburg, Kansas, Supercell into a Numerical Cloud Model  

E-Print Network [OSTI]

Kalman filter (EnKF) technique into a non- hydrostatic, compressible numerical weather prediction model weather prediction (NWP) models to improve under- standing of convective storm dynamics is now a fairly, Kansas, Supercell into a Numerical Cloud Model ROBIN L. TANAMACHI,*,1,# LOUIS J. WICKER,@ DAVID C. DOWELL

Xue, Ming

353

Reflection Spectra from Photoionized Accretion Discs  

E-Print Network [OSTI]

We review recent progress on the modeling and use of reflection spectra from irradiated and ionized accretion discs. On the computational side, calculations of reflection spectra from discs with non-uniform density structure have shown that thermal instabilities can effect the predictions. Ionized reflection spectra have been used effectively in fitting data of Narrow-Line Seyfert 1 galaxies, and have placed constraints on the strength and shape of soft X-ray emission lines.

D. R. Ballantyne; R. R. Ross; A. C. Fabian

2002-04-16T23:59:59.000Z

354

Sample Observations from the 2001.Multi-Frequency Radar IOP  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Sample Observations from the 2001 Sample Observations from the 2001 Multi-Frequency Radar IOP C. R. Williams Cooperative Institute for Research in Environmental Sciences University of Colorado Boulder, Colorado C. R. Williams and K. S. Gage National Oceanic and Atmospheric Administration Aeronomy Laboratory Boulder, Colorado L. Leon and S. Cruz-Pol University of Puerto Rico Mayaguez Campus S. M. Sekelsky Microwave Remote Sensing Laboratory University of Massachusetts Amherst, Massachusetts Introduction The 2001 Multi-Frequency Radar Intensive Operational Period (IOP) was designed to collect a long dataset of W-band (95 GHz), Ka-band (35 GHz), and S-band (2.8 GHz) vertical profiling observations to investigate insect scattering and precipitating particle scattering above the Southern Great Plains

355

Applicability of radar observations to the prediction of storm runoff  

E-Print Network [OSTI]

of Depaverne. (Yiembe~ 1967 (Yonwh) (Yea ) ABSTRACT Rainfall-runoff relaL'ronships fox 18 storms over the Little Nashita River basin in Oklahoma are studied in order to develop a method for predicting storm losses based on weather-radar observational..., for the use of their computer facilities. Credit is due Mr. M. A. Hartman, Chief Research Engineer, Agricultural Research Service, Chickasha, Oklahoma, for his assistance in obtaining treamflow and rainfall data from records maintained by the Agricultural...

Johnson, Odell Monroe

2012-06-07T23:59:59.000Z

356

Reverse Doppler effect of magnons with negative group velocity scattered from a moving Bragg grating  

Science Journals Connector (OSTI)

We demonstrate experimentally and theoretically the reverse Doppler effect when magnons with negative group velocity are reflected off a moving Bragg grating. This grating, which represents a moving magnonic crystal, is created in an yttrium-iron-garnet film by the periodic strain induced by a traveling surface acoustic wave. As reflection occurs from a crystal rather than from a single reflecting surface, the wave number of the scattered wave is strictly determined by a momentum conservation law. Magnons scattered from the approaching (receding) magnonic crystal are found to be shifted down (up) in frequency. This result, together with an earlier report of reverse Doppler shift from moving sources [D. D. Stancil et al., Phys. Rev. B, 74, 060404(R) (2006)], establishes that the reverse Doppler effect is a universal phenomenon in systems with negative group velocity and not restricted to left-handed materials.

A. V. Chumak; P. Dhagat; A. Jander; A. A. Serga; B. Hillebrands

2010-04-16T23:59:59.000Z

357

Progress with On-The-Fly Neutron Doppler Broadening in MCNP  

SciTech Connect (OSTI)

The University of Michigan, ANL, and LANL have been collaborating on a US-DOE-NE University Programs project 'Implementation of On-the-Fly Doppler Broadening in MCNP5 for Multiphysics Simulation of Nuclear Reactors.' This talk describes the project and provides results from the initial implementation of On-The-Fly Doppler broadening (OTF) in MCNP and testing. The OTF methodology involves high precision fitting of Doppler broadened cross-sections over a wide temperature range (the target for reactor calculations is 250-3200K). The temperature dependent fits are then used within MCNP during the neutron transport, for OTF broadening based on cell temperatures. It is straightforward to extend this capability to cover any temperature range of interest, allowing the Monte Carlo simulation to account for a continuous distribution of temperature ranges throughout the problem geometry.

Brown, Forrest B. [Los Alamos National Laboratory; Martin, William R. [Los Alamos National Laboratory; Yesilyurt, Gokhan [Argonne National Laboratory; Wilderman, Scott [University of Michigan

2012-06-18T23:59:59.000Z

358

Why should we correct reported pulsation frequencies for stellar line-of-sight Doppler velocity shifts?  

E-Print Network [OSTI]

In the age of Kepler and Corot, extended observations have provided estimates of stellar pulsation frequencies that have achieved new levels of precision, regularly exceeding fractional levels of a few parts in $10^{4}$. These high levels of precision now in principle exceed the point where one can ignore the Doppler shift of pulsation frequencies caused by the motion of a star relative to the observer. We present a correction for these Doppler shifts and use previously published pulsation frequencies to demonstrate the significance of the effect. We suggest that reported pulsation frequencies should be routinely corrected for stellar line-of-sight velocity Doppler shifts, or if a line-of-sight velocity estimate is not available, the frame of reference in which the frequencies are reported should be clearly stated.

Davies, G R; Miglio, A; Campante, T L; Chaplin, W J; Elsworth, Y

2014-01-01T23:59:59.000Z

359

Effects of Doppler broadening on Autler-Townes splitting in six-wave mixing  

SciTech Connect (OSTI)

The effects of Doppler broadening on Autler-Townes (AT) splitting in six-wave mixing (SWM) are investigated by the dressed-state model. We analyze the velocities at which the atoms are in resonance with the dressed states through Doppler frequency shifting and find that, depending on the wave-number ratio, there may be two resonant velocities which can originate from resonance with one of the dressed states or from resonance with two different dressed states. Based on this model, we discuss a novel type of AT doublet in the SWM spectrum, where macroscopic effects play an important role. Specifically, the existence of resonant peaks requires polarization interference between atoms of different velocities in addition to a change in the number of resonant atoms involved. Our model can also be employed to analyze electromagnetically induced transparency resonance and other types of Doppler-free high-resolution AT spectroscopy.

Niu Jinyan [Laboratory of Optical Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); School of Mathematics, Physics and Biological Engineering, Inner Mongolia University of Science and Technology, Baotou 014010 (China); Pei Liya; Lu Xiaogang; Wang Ruquan; Wu Lingan; Fu Panming [Laboratory of Optical Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China)

2011-09-15T23:59:59.000Z

360

Intrinsic Lorentz violation in Doppler effect from a moving point light source  

E-Print Network [OSTI]

Einstein's Doppler formula is not applicable when a moving point light source is close enough to the observer; for example, it may break down or cannot specify a determinate value when the point source and the observer overlap. In this paper, Doppler effect for a moving point light source is analyzed, and it is found that the principle of relativity allows the existence of intrinsic Lorentz violation. A conceptual scheme to experimentally test the point-source Doppler effect is proposed, and such a test could lead to an unexpected result that the frequency of a photon may change during propagation, which questions the constancy of Planck constant since the energy conservation in Einstein's light-quantum hypothesis must hold.

Changbiao Wang

2010-07-06T23:59:59.000Z

Note: This page contains sample records for the topic "radar doppler spectra" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Optical frequency standards for gravitational wave detection using satellite Doppler velocimetry  

E-Print Network [OSTI]

Gravitational waves imprint apparent Doppler shifts on the frequency of photons propagating between an emitter and detector of light. This forms the basis of a method to detect gravitational waves using Doppler velocimetry between pairs of satellites. Such detectors, operating in the milli-hertz gravitational frequency band, could lead to the direct detection of gravitational waves. The crucial component in such a detector is the frequency standard on board the emitting and receiving satellites. We point out that recent developments in atomic frequency standards have led to devices that are approaching the sensitivity required to detect gravitational waves from astrophysically interesting sources. The sensitivity of satellites equipped with optical frequency standards for Doppler velocimetry is examined, and a design for a robust, space-capable optical frequency standard is presented.

Vutha, Amar C

2015-01-01T23:59:59.000Z

362

Spectra/Por Easy-to-Use  

E-Print Network [OSTI]

Spectra/Por® Easy-to-Use Dialysis Membrane Products Micro DispoDialyzer® Float-A-Lyzer® DispoDialyzer® A Dialysis Device for Ultra Micro Volume Samples The Micro DispoDialyzer was developed for efficiently dia ratio for a faster dialysis rate. Spectra/Por MicroDispoDialyzer is packaged wet individu- ally in 0

Lebendiker, Mario

363

Estimation and Assessment of Errors Related to Antenna Pattern Distortion in CODAR SeaSonde High-Frequency Radar Ocean Current Measurements  

Science Journals Connector (OSTI)

A simulation-based investigation of errors in HF radar–derived, near-surface ocean current measurements is presented. The simulation model is specific to Coastal Ocean Dynamics Application Radar (CODAR) SeaSonde radar systems that employ a ...

Kenneth Laws; Jeffrey D. Paduan; John Vesecky

2010-06-01T23:59:59.000Z

364

Effect of a spectral line with Doppler broadening on optical bistability in a ring cavity  

Science Journals Connector (OSTI)

We discuss the effect of a spectral line with Doppler broadening on optical bistability in a ring cavity which contains a saturable absorber of two-level atoms. In this paper, we first derive a generalized equation that is satisfied by the output light intensity of this system from the Langevin equations in H. Haken’s Laser Theory (Springer, Heidelberg, 1970). Then, we simplify the generalized equation for a single mode. We study the single-mode equation for both nonexisting and existing spontaneous emission and obtain the result that the square of the bistability loop increases with the increase of Doppler broadening of the spectral line.

Feng Qi-yuan; Liu Ya-jie; Yang Xing-yu

1988-10-15T23:59:59.000Z

365

Radiative transfer effects on Doppler measurements as sources of surface effects in sunspot seismology  

E-Print Network [OSTI]

We show that the use of Doppler shifts of Zeeman sensitive spectral lines to observe wavesn in sunspots is subject to measurement specific phase shifts arising from, (i) altered height range of spectral line formation and the propagating character of p mode waves in penumbrae, and (ii) Zeeman broadening and splitting. We also show that these phase shifts depend on wave frequencies, strengths and line of sight inclination of magnetic field, and the polarization state used for Doppler measurements. We discuss how these phase shifts could contribute to local helioseismic measurements of 'surface effects' in sunspot seismology.

S. P. Rajaguru; K. Sankarasubramanian; R. Wachter; P. H. Scherrer

2006-11-29T23:59:59.000Z

366

Importance of the Doppler Effect to the Determination of the Deuteron Binding Energy  

E-Print Network [OSTI]

The deuteron binding energy extracted from the reaction ${}^1H(n,\\gamma){}^2H$ is reviewed with the exact relativistic formula, where the initial kinetic energy and the Doppler effect are taken into account. We find that the negligible initial kinetic energy of the neutron could cause a significant uncertainty which is beyond the errors available up to now. Therefore, we suggest an experiment which should include the detailed informations about the initial kinetic energy and the detection angle. It could reduce discrepancies among the recently reported values about the deuteron binding energy and pin down the uncertainty due to the Doppler broadening of $\\gamma$ ray.

Yongkyu Ko; Myung Ki Cheoun; Il-Tong Cheon

1999-04-01T23:59:59.000Z

367

Observation of a Motional Stark Effect to Determine the Second-Order Doppler Effect  

Science Journals Connector (OSTI)

The high resolution two-photon spectroscopy of hydrogen is often limited by the second-order Doppler effect. To determine this effect, we apply a magnetic field perpendicular to the atomic beam. This field induces a quadratic motional Stark shift proportional, as the second-order Doppler effect, to v2 (v atomic velocity). For some magnetic field, these two effects are opposite and the total shift due to the atomic velocity is reduced. We present the first observation of this effect for the 1S-3S transition in hydrogen.

G. Hagel; R. Battesti; F. Nez; L. Julien; F. Biraben

2002-10-23T23:59:59.000Z

368

Time delay and Doppler tests of the Lorentz symmetry of gravity  

SciTech Connect (OSTI)

Modifications to the classic time-delay effect and Doppler shift in general relativity (GR) are studied in the context of the Lorentz-violating standard-model extension (SME). We derive the leading Lorentz-violating corrections to the time-delay and Doppler shift signals, for a light ray passing near a massive body. It is demonstrated that anisotropic coefficients for Lorentz violation control a time-dependent behavior of these signals that is qualitatively different from the conventional case in GR. Estimates of sensitivities to gravity-sector coefficients in the SME are given for current and future experiments, including the recent Cassini solar conjunction experiment.

Bailey, Quentin G. [Physics Department, Embry-Riddle Aeronautical University, 3700 Willow Creek Road, Prescott, Arizona 86301 (United States)

2009-08-15T23:59:59.000Z

369

E-Print Network 3.0 - avoid radar installations Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

to 9o differences in flow directions. 1. INTRODUCTION We installed the first HF radar at Coal Oil... Evaluating radial component current measurements from CODAR high frequency...

370

E-Print Network 3.0 - automotive radar systems Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

POPULAR MECHANICS THE INTELLIGENT EYE Summary: days of technical conferences at the 2004 SAE World Congress. http:www.popularmechanics.comautomotive... 's radar distance...

371

Probability distribution of low-altitude propagation loss from radar sea clutter data  

E-Print Network [OSTI]

: propagation loss estimation, radar clutter, probabilistic inversion Citation: Gerstoft, P., W. S. Hodgkiss, L within the marine atmospheric surface layer [Liu et al., 1979]. The refractivity profile above

Buckingham, Michael

372

E-Print Network 3.0 - aperture radar imagery Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

capability... scar extents and fire severity for wildfire management and control. All-weather satellite radar imagery... in understanding and forecasting natural hazards....

373

E-Print Network 3.0 - aperture radar image Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

flight trajecto- In synthetic aperture radar (SAR) imaging a scene... -y(s). The projection data and reconstructed ... Source: Yazici, Birsen - Department of Electrical,...

374

Low complexity multipath and Doppler-shift correction algorithm for reliable underwater Coherent-FSK acoustic modems: short paper  

Science Journals Connector (OSTI)

This paper presents an innovative algorithm for Doppler-shift and multipath correction in a coherent-FSK modem, which is optimized for acoustic communications in shallow water underwater networks. The final modem will be used in the ANDREA project, whose ... Keywords: Doppler-shift, acoustic modem, multipath correction, underwater networks, wireless sensor networks

A. Sanchez; S. Climent; P. Yuste; A. Perles-Ivars; J. J. Serrano

2012-11-01T23:59:59.000Z

375

An Autonomous Doppler Sodar Wind Profiling System PHILIP S. ANDERSON, RUSSELL S. LADKIN, AND IAN A. RENFREW  

E-Print Network [OSTI]

An Autonomous Doppler Sodar Wind Profiling System PHILIP S. ANDERSON, RUSSELL S. LADKIN, AND IAN A form 27 September 2004) ABSTRACT An autonomous Doppler sodar wind profiling system has been designed panels, and two vertical axis wind generators, plus charging control and isolation circuitry. The sodar

Renfrew, Ian

376

Toward a Diurnal Climatology of Cold-Season Turbulence Statistics in Continental Stratocumulus as Observed by the Atmospheric Radiation Millimeter- Wavelength Cloud Radars  

SciTech Connect (OSTI)

Numerous observational studies of marine stratocumulus have demonstrated a pronounced diurnal cycle. At night, longwave flux divergence at the top of the cloud drives negatively buoyant eddies that tend to keep the boundary layer well mixed. During the day, solar absorption by the cloud tends to reduce the turbulent intensity and often decouples the planetary boundary layer (PBL) into cloud- and sub-cloud circulations. The delicate balance between turbulent intensity, entrainment, and fluxes dictates cloud geometry and persistence, which can significantly impact the shortwave radiation budget. Millimeter-wavelength cloud radars (MMCRs) have been used to study the turbulent structure of boundary layer stratocumulus (e.g. Frisch et al. 1995; Kollias and Albrecht 2000). Analysis is confined to nondrizzling or lightly drizzling cloud systems for which precipitation contamination is negligible. Under such assumptions the Doppler velocity field becomes a proxy for vertical velocity. Prior research has mainly consisted of a few case studies of specific cloud systems using radar scan strategies optimized for this particular cloud type. The MMCR operating at the Southern Great Plains Atmospheric Radiation Measurement Climate Research Facility is broadly configured to be able to detect many different cloud types over a broad range of reflectivities and altitudes, so it is not specifically optimized for PBL clouds. Being in more-or-less continuous operation since the end of 1996, it does, however, have the advantage of long data coverage, which suggests that statistically significant measures of the diurnal cycle of turbulence should be attainable. This abstract summarizes the first few steps toward this goal, using 7 months of cold season MMCR data.

Mechem, D.B.; Kogan, Y.L.; Childers, M.E.; Donner, K.M.

2005-03-18T23:59:59.000Z

377

Improving ISR Radar Utilization (How I quit blaming the user and made the radar easier to use).  

SciTech Connect (OSTI)

In modern multi - sensor multi - mode Intelligence, Surveillance, and Reconnaissance ( ISR ) platforms, the plethora of options available to a sensor/payload operator are quite large, leading to an over - worked operator often down - selecting to favorite sensors an d modes. For example, Full Motion Video (FMV) is justifiably a favorite sensor at the expense of radar modes, even if radar modes can offer unique and advantageous information. The challenge is then to increase the utilization of the radar modes in a man ner attractive to the sensor/payload operator. We propose that this is best accomplished by combining sensor modes and displays into 'super - modes'. - 4 - Acknowledgements This report is the result of a n unfunded research and development activity . Sandia Natio nal Laboratories is a multi - program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE - AC04 - 94AL850 00.

Doerry, Armin W.

2014-08-01T23:59:59.000Z

378

Dual-Doppler observations of the formative stage of an asymmetric squall line system  

E-Print Network [OSTI]

-rclativc winds at 5. 1 km for 1853 UTC . . . 37 Figure 15: Same as fig. 13 except for 1930 UTC. . . . Figure 16: Same as fig. 14 except for 1930 UTC Figure 17: Radar reflectivity field and vertical velocity at 10. 1 km for 1930 IJTC 42 . . . 39 . . 41... synthesized to obtain u and v wind components, and thc data had been advected to account I'or storm evolution, the u and v wind fields were corrected for falling hydrometeors. The terminal velocity of a hydrometeor, Vr, can be related to the radar...

Jamieson, Daniel Richard

2012-06-07T23:59:59.000Z

379

Rotational Corrections to Neutron-Star Radius Measurements from Thermal Spectra  

E-Print Network [OSTI]

We calculate the rotational broadening in the observed thermal spectra of neutron stars spinning at moderate rates in the Hartle-Thorne approximation. These calculations accurately account for the effects of the second-order Doppler boosts as well as for the oblate shapes and the quadrupole moments of the neutron stars. We find that fitting the spectra and inferring the bolometric fluxes under the assumption that a star is not rotating causes an underestimate of the inferred fluxes and, thus, radii. The correction depends on the stellar spin, radius, and observer's inclination. For a 10 km neutron star spinning at 600 Hz, the rotational correction to the flux is ~1-4%, while for a 15 km neutron star with the same spin period, the correction ranges from 2% for pole-on sources to 12% for edge-on sources. We calculate the inclination-averaged corrections to inferred radii as a function of the neutron-star radius and mass and provide an empirical formula for the corrections. For realistic neutron star parameters (1.4 M$_\\odot$, 12 km, 600 Hz), the stellar radius is on the order of 4% larger than the radius inferred under the assumption that the star is not spinning.

Michi Baubock; Feryal Ozel; Dimitrios Psaltis; Sharon M. Morsink

2014-07-11T23:59:59.000Z

380

Rotational Corrections to Neutron-Star Radius Measurements from Thermal Spectra  

E-Print Network [OSTI]

We calculate the rotational broadening in the observed thermal spectra of neutron stars spinning at moderate rates in the Hartle-Thorne approximation. These calculations accurately account for the effects of the second-order Doppler boosts as well as for the oblate shapes and the quadrupole moments of the neutron stars. We find that fitting the spectra and inferring the bolometric fluxes under the assumption that a star is not rotating causes an underestimate of the inferred fluxes and, thus, radii. The correction depends on the stellar spin, radius, and observer's inclination. For a 10 km neutron star spinning at 600 Hz, the rotational correction to the flux is ~1-4%, while for a 15 km neutron star with the same spin period, the correction ranges from 2% for pole-on sources to 12% for edge-on sources. We calculate the inclination-averaged corrections to inferred radii as a function of the neutron-star radius and mass and provide an empirical formula for the corrections. For realistic neutron star parameters ...

Baubock, Michi; Psaltis, Dimitrios; Morsink, Sharon M

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "radar doppler spectra" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

SoundWave: Using the Doppler Effect to Sense Gestures Sidhant Gupta1,2  

E-Print Network [OSTI]

custom patch antennas. They used the reflected Doppler- shifted signal to infer human motion and upper-facing RGB webcam to allow the user to control PowerPoint slides or music/video playback. Unfortunately) and require quite a bit of processing power. The Microsoft Xbox Kinect is another example of a successfully

Anderson, Richard

382

Progress towards an accurate determination of the Boltzmann constant by Doppler spectroscopy  

E-Print Network [OSTI]

, 27] consists in recording the Doppler profile of a well- isolated absorption line of an atomic absorption profile of a line in a gas of ammonia at thermal equilibrium. This optical method based) ppm broadening of the absorption linewidth. We also show that, in our well chosen experimental

383

Improved forecasts of extreme weather events by future space borne Doppler wind lidar  

E-Print Network [OSTI]

sensitive areas. To answer these questions simulation experiments with state-of-the-art numerical weather prediction (NWP) models have proved great value to test future meteorological observing systems a prioriImproved forecasts of extreme weather events by future space borne Doppler wind lidar Gert

Marseille, Gert-Jan

384

The Impact of Doppler Spreading on Delay Performance over Multi-hop Wireless Communications  

E-Print Network [OSTI]

promising technologies to provide high data rate transmission through wireless link in multi-hop networks-to-end delay performance over multi-hop wireless transmission. In this paper, we study the impact of Doppler communications are very promising technologies for next generation network to provide high data rate transmission

Haddadi, Hamed

385

Observation of fast-ion Doppler-shifted cyclotron resonance with shear Alfvn waves  

E-Print Network [OSTI]

are produced by neutral or ion beam injection,1 by ion cyclotron2 or lower hybrid heating,3 and by fusion ions by Alfvén waves well below the ion cyclotron resonance frequency might cause ion heatingObservation of fast-ion Doppler-shifted cyclotron resonance with shear Alfvén waves Yang Zhang,1 W

Heidbrink, William W.

386

The game of the "very small" and the "very big": The case of the Doppler Effect  

E-Print Network [OSTI]

In the study of the Doppler Effect, non-locality is not taken into account. We present two cases in which a continuous change in the receiver's speed and in the angle at which the successive wavecrests are received takes place. In each case the error committed by not taking into account the non-locality is evaluated.

Bernhard Rothenstein; Albert Rothenstein

2003-08-27T23:59:59.000Z

387

INFLUENCE OF DOPPLER WIDTH FLUCTUATIONS ON THE SHAPE OF SPECTRAL LINES  

SciTech Connect (OSTI)

We investigate the influence of stochastic Doppler width fluctuations on the shape of spectral lines. The photospheres and atmospheres of stars, and the interstellar medium, possess stochastic behavior especially near nonstationary objects such as active galactic nuclei, quasars, flare stars, and regions of star formation. In reality, we observe the mean values of intensities from these objects. In most situations, the spectral line extinction coefficient has a Gaussian shape with the stochastic Doppler width determined by thermal and small-scale turbulent motions of atoms or molecules. For small-scale turbulent motions (short-correlated turbulence) the propagation of radiation is described by the average extinction factor. This coefficient depends on the level of the Doppler width fluctuations {eta}. We show that these fluctuations change both the value of intensity and the shape of spectral lines. We consider distortions of the spectral line shapes for the absorption and emission lines for various values of the parameter {eta}. For a number of H{sub 2}O maser sources we estimate the values of this parameter, the optical depths of the inverted media, and the mean effective Doppler velocities. Maser emission lines with non-Gaussian shape can serve as an additional method for the investigation of the physical parameters in maser 'spots'.

Silant'ev, N. A.; Lekht, E. E. [Instituto Nacional de AstrofIsica, Optica y Electronica, Apartado Postal 51 y 216, 72840, Tonantzintla, Puebla (Mexico); Alexeeva, G. A. [Central (Pulkovo) Astronomical Observatory of Russian Academy of Sciences, Pulkovskoe shosse 65, St. Petersburg, 196140 (Russian Federation)], E-mail: silant@inaoep.mx

2009-05-10T23:59:59.000Z

388

Lie symmetry analysis of electron–electromagnetic wave interaction under condition of the anomalous Doppler effect  

Science Journals Connector (OSTI)

Abstract Lie symmetry analysis is applied for a problem of interaction of electron cyclotron oscillators with a slow electromagnetic wave under condition of the anomalous Doppler effect. This analysis reveals scaling invariance of the system and existence of self-similar solutions which describe amplification of a short electromagnetic pulse with its subsequent compression. The results of theoretical analysis are confirmed by numerical simulations.

N.M. Ryskin

2014-01-01T23:59:59.000Z

389

Periodic Flux Variability of Stars due to the Reflex Doppler Effect Induced by Planetary Companions  

E-Print Network [OSTI]

Upcoming space-based photometric satellites offer the possibility of detecting continuum flux variability at the micro-magnitude level. We show that the Doppler flux variability induced by the reflex motion of stars due to planetary companions has an amplitude of (3-alpha)K/c, where K is the reflex radial velocity amplitude and alpha is the logarithmic slope of source spectral flux in the observed frequency band. For many of the known close-in planetary systems with periods less than ~0.2 years, the periodic Doppler variability is of order a micromagnitude, and is significant relative to the variability caused by reflected light from the planetary companion. For companions with periods greater than ~0.2 years, the Doppler signal is larger than the reflected light signal. We show that the future photometric satellites should reach the sensitivity to detect this Doppler variability. In particular, the Kepler satellite should have the photon-noise sensitivity to detect at a signal-to-noise ratio > 5, all planets with minimum mass greater than 5 Jupiter masses, and periods less than 0.1 years around the 10,000 main-sequence stars with spectral types A through K and apparent magnitude V<12 in its field-of-view.

Abraham Loeb; B. Scott Gaudi

2003-03-10T23:59:59.000Z

390

Doppler effect in fragment autoionization following core-to-valence excitation in O{sub 2}  

SciTech Connect (OSTI)

Atomic autoionization following O 1s resonant excitation in O{sub 2} is studied using high-resolution electron spectroscopy. The resonant Auger spectrum showing evidence of ultrafast dissociation as well as the autoionization of oxygen atoms is measured and discussed. Evidence of the electronic Doppler effect is observed in both electronic decay mechanisms.

Guillemin, Renaud; Simon, Marc; Shigemasa, Eiji [Universite Pierre et Marie Curie, Laboratoire de Chimie Physique-Matiere et Rayonnement, UMR 7614, 11 rue Pierre et Marie Curie, F-75231 Paris Cedex 05, France and Centre National de la Recherche Scientifique, Laboratoire de Chimie Physique-Matiere et Rayonnement, UMR 7614, 11 rue Pierre et Marie Curie, F-75231 Paris Cedex 05 (France); Ultraviolet Synchrotron Orbital Radiation Facility, Institute for Molecular Science, Okazaki 444-8585 (Japan)

2010-11-15T23:59:59.000Z

391

Experimental Investigation of the Effect of Speckle Noise on Continuous Scan Laser Doppler Vibrometer Measurements  

E-Print Network [OSTI]

Period i : Phase Variable v : Voltage Signal fsamp : Sampling Frequency y : Response Signal fscan Research Building 1500 Engineering Drive Madison, WI 53706 Abstract Continuous Scan Laser Doppler when the scan frequency is high relative to the highest natural frequency of interest, and state

Allen, Matthew S.

392

Estimation of Ground-Level Reflectivity Factor in Operational Weather Radar Networks Using VPR-Based Correction Ensembles  

Science Journals Connector (OSTI)

An operational method is presented that corrects the bias of radar-based quantitative precipitation estimations (QPE) in radar networks that is due to the vertical profile of reflectivity (VPR) factor. It is used in both rain and snowfall. ...

Jarmo Koistinen; Heikki Pohjola

2014-10-01T23:59:59.000Z

393

UNLOCKING THE TREASURE CHEST OF LEVEL-II RADAR DATA: LESSONS IN TECHNOLOGY TRANSFER POLICY FOR THE ATMOSPHERIC SCIENCES  

E-Print Network [OSTI]

P 1.6 UNLOCKING THE TREASURE CHEST OF LEVEL-II RADAR DATA: LESSONS IN TECHNOLOGY TRANSFER POLICY This analysis of Level-II radar data presents a great success story about partnerships in technology transfer

394

30 ENGINEERING & SCIENCE WI NTE R 2012 Whether processing radar signals in Norway or assessing rock properties in Nigeria, Calte  

E-Print Network [OSTI]

deeply into basic physics to solve problems. Oslo, Norway, José Navarro, PhD '94, Astronomy José Navarro, Navarro integrates radar into systems for maritime traffic services. Since radar installations are usually

395

Testing Climate Models Using Thermal Infrared Spectra  

Science Journals Connector (OSTI)

An approach to test climate models with observations is presented. In this approach, it is possible to directly observe the longwave feedbacks of the climate system in time series of annual average outgoing longwave spectra. Tropospheric ...

Stephen Leroy; James Anderson; John Dykema; Richard Goody

2008-05-01T23:59:59.000Z

396

Mesospheric observations with the EISCAT UHF radar during polar cap absorption events  

E-Print Network [OSTI]

atmosphere these heights are in the middle and upper mesosphere and lower thermosphere. The ability to apply of the scattering medium. For the low plasma densities in the D-region the longer wavelength of the EISCAT VHF radar of 1985 with the 933-MHz UHF radar (E. Turunen et al., 1988; Collis et al., 1988). Details

Paris-Sud XI, Université de

397

Planning of Low-Cost 77-GHz Radar Transceivers for Automotive Applications  

E-Print Network [OSTI]

. Moghavvemi University ofMalaya INTRODUCTION The use of electronics in the automotive industry will reach (orPlanning of Low-Cost 77-GHz Radar Transceivers for Automotive Applications H. Ameri, A. Attaran & M the position and speed as with other components used in the automotive industry, radars will find widespread

Paris-Sud XI, Université de

398

Small scale turbulence and instabilities observed simultaneously by radiosondes and the MU radar.  

E-Print Network [OSTI]

Small scale turbulence and instabilities observed simultaneously by radiosondes and the MU radar. R-French field campaign devoted to study small-scale turbulence and instabilities in the lower atmosphere for retrieving small-scale turbulence parameters from ST radars. However, the dominant sources

399

Radar and Lightning Observations of Normal and Inverted Polarity Multicellular Storms from STEPS  

E-Print Network [OSTI]

, as well as extraordinary total flash rates as high as 500 min 1 . The National Lightning Detection NetworkRadar and Lightning Observations of Normal and Inverted Polarity Multicellular Storms from STEPS received 11 July 2006, in final form 15 February 2007) ABSTRACT This study discusses radar and lightning

Rutledge, Steven

400

Radar Vibrometry: Investigating the Potential of RF microwaves to measure vibrations  

E-Print Network [OSTI]

Radar Vibrometry: Investigating the Potential of RF microwaves to measure vibrations K A Tsolis, C classification process. Recent research on vibrometry, the process of conducting vibration measurements. With this study we make a primary investigation of the capabilities of RF radar systems to measure vibrations. We

Haddadi, Hamed

Note: This page contains sample records for the topic "radar doppler spectra" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

A comparison of velocity measurements from the CUTLASS Finland radar and the EISCAT UHF system  

E-Print Network [OSTI]

A comparison of velocity measurements from the CUTLASS Finland radar and the EISCAT UHF system J. A January 1999 Abstract. The CUTLASS Finland radar, which com- prises an integral part of the Super irregularities within a ®eld-of- view which extends over some four million square kilometres. Within the Finland

Paris-Sud XI, Université de

402

Finland HF and Esrange MST radar observations of polar mesosphere summer echoes  

E-Print Network [OSTI]

Finland HF and Esrange MST radar observations of polar mesosphere summer echoes Tadahiko Ogawa1 (200x) xx:1­8 Finland HF and Esrange MST radar observations of polar mesosphere summer echoes Tadahiko in Finland are presented. The echoes were detected at four frequencies of 9, 11, 13 and 15 MHz at slant

Kirkwood, Sheila

403

Global mapping and characterization of Titan's dune fields with Cassini: Correlation between RADAR and VIMS observations  

E-Print Network [OSTI]

and VIMS observations S. Rodriguez a, , A. Garcia a , A. Lucas a , T. Appéré a , A. Le Gall b , E. Reffet the Cassini RADAR and VIMS (Visual and Infrared Mapping Spectrometer) images ­ the latter being empirically. Furthermore, the strong correlation between RADAR-mapped dunes and the VIMS ``dark brown'' unit (72%) allows

Narteau, Clément

404

Development of an Ultra-Wideband Radar System for Vehicle Detection at Railway Crossings  

E-Print Network [OSTI]

Development of an Ultra-Wideband Radar System for Vehicle Detection at Railway Crossings Stephen P-wideband (UWB) radar system designed to detect motor vehicles such as cars and trucks when they are present was supported in part by LaBarge, Inc. down. A sensing system that can detect the presence of a vehicle

Kansas, University of

405

Bistatic radar imaging of the marine environment. Part II: simulation and results analysis  

E-Print Network [OSTI]

operational interest for instance to detect oil spills or ship wakes [5]­[7]. Since a large coverage1 Bistatic radar imaging of the marine environment. Part II: simulation and results analysis present a bistatic, polarimetric and real aper- ture Marine Radar Simulator (MaRS) producing pseudo

Boyer, Edmond

406

Upper Air Wind Measurements by Weather Radar Iwan Holleman, Henk Benschop, and Jitze van der Meulen  

E-Print Network [OSTI]

or assimilated into numerical weather prediction (NWP) models. Un- der the assumption of a linear wind field background statistics of the weather radar wind profiles against the Hirlam NWP model are at least as good of the VVP wind profiles against the Hirlam NWP model demonstrate the high quality of weather radar wind

Stoffelen, Ad

407

VALIDATION OF RAIN RATE RETRIEVALS FROM SEVIRI USING WEATHER RADAR OBSERVATIONS  

E-Print Network [OSTI]

and for improving parameterization cloud processes in numerical weather prediction (NWP) models or assimilation in these models. Although operational networks of Weather Radars are expanding over Europe and the United StatesVALIDATION OF RAIN RATE RETRIEVALS FROM SEVIRI USING WEATHER RADAR OBSERVATIONS R. A. Roebeling

Stoffelen, Ad

408

Ground-penetrating-radar-assisted saturation and permeability estimation in bimodal systems  

E-Print Network [OSTI]

and to subsequently design an efficient and reliable remediation plan. Soil water content monitoring is importantGround-penetrating-radar-assisted saturation and permeability estimation in bimodal systems Susan S from ground penetrating radar (GPR), a noninvasive, high-resolution geophysical method. The procedures

Hubbard, Susan

409

Weather Forecasting by Interactive Analysis of Radar and Satellite Imagery [and Discussion  

Science Journals Connector (OSTI)

...1988 research-article Weather Forecasting by Interactive Analysis of Radar and Satellite Imagery [and Discussion...presenting the current weather situation quickly enough...processing of the radar and satellite data is highly automated...very busy in active weather situations, can keep...

1988-01-01T23:59:59.000Z

410

SEVERE WEATHER WARNING APPLICATION DEVELOPMENT AT NSSL USING MULTPLE RADARS AND MULTIPLE SENSORS  

E-Print Network [OSTI]

, mesoscale models, satellite, lightning, etc.). Therefore, these traditional single-radar severe weather8.3 SEVERE WEATHER WARNING APPLICATION DEVELOPMENT AT NSSL USING MULTPLE RADARS AND MULTIPLE Storms Laboratory has played the primary role in the development and evaluation of National Weather

Smith, Travis

411

A Dual-Polarization Radar Hydrometeor Classification Algorithm for Winter Precipitation  

E-Print Network [OSTI]

associated with winter storm precipitation type, accumulation, and timing is a major forecasting, safetyA Dual-Polarization Radar Hydrometeor Classification Algorithm for Winter Precipitation ELIZABETH J The purpose of this study is to demonstrate the use of polarimetric observations in a radar-based winter

Collett Jr., Jeffrey L.

412

Winter Precipitation Microphysics Characterized by Polarimetric Radar and Video Disdrometer Observations in Central Oklahoma  

E-Print Network [OSTI]

the microphysics of winter storms with different types of precipitation. In general, warm rain events are studied. (2007) used polarimetric radar observations for winter precipitation not having the mixed phaseWinter Precipitation Microphysics Characterized by Polarimetric Radar and Video Disdrometer

Xue, Ming

413

Polarimetric Radar Observation Operator for a Cloud Model with Spectral Microphysics  

E-Print Network [OSTI]

-proven advantages such as hydro- meteor classification and improvement in radar data quality and rainfall modeling via improvement of micro- physical parameterization and direct assimilation of polarimetric radar the output of numerical cloud models was pioneered using the models with bulk parameterization of cloud micro

Mark, Pinsky

414

Operational Monitoring of Weather Radar Receiving Chain Using the Sun IWAN HOLLEMAN  

E-Print Network [OSTI]

Operational Monitoring of Weather Radar Receiving Chain Using the Sun IWAN HOLLEMAN Royal, is presented. The ``online'' method is entirely based on the analysis of sun signals in the polar volume data- termining the weather radar antenna pointing at low elevations using sun signals, and it is suited

Stoffelen, Ad

415

On the effects of atmospheric refraction on radar ground patterns  

E-Print Network [OSTI]

of superrefraction. A radial pattern of AP echoes occurred in a number of cases when there was a strong gradient of N in an elevated refractive layer, but this pattern was not nearly as common as others. Investigations [10, 13, 14, 15, 16] of the atmosphere... when the antenna elevation angle is less than 2 deg and when there is an elevated refracting layer between 1500 ft and 3000 ft above the radar in which the gradient of refractivity is greater than 48N/1000 ft. ACKNONLEDGMENT The author wishes...

Cobb, Lalovee Glendale

1963-01-01T23:59:59.000Z

416

Radar investigation of the Cote Blanche salt dome  

E-Print Network [OSTI]

PADAR IiVVESTICATIOH CF THE COZE ELANCHR SALT DO&: A Thests EOHEET DOSAED SZEVAET Subm-'tt. ii' to the Crsduete Coilege of Ter: s AVi', i;nlu xsity in partfal fulfi' line?t of th ': quiremen fc z' tht degree o %P t S "t Clt. 'iCE iugust. l...HIC major Sub jest: Ceoohysfes RADAR INVESTIGATION OP THE COTE BLANCHE SALT DOME A Thesis by ROBERT DONALD STEWART Approved as to style and nor. tent by: (Chairman of Comml ee) ( Ir~c" (Head of De rtment ? Member) (Member) August 1974 ABSTRACT...

Stewart, Robert Donald

2012-06-07T23:59:59.000Z

417

Digitized dual wavelength radar data from a Texas thunderstorm  

E-Print Network [OSTI]

for 1600 CST (Figure 12, p 34; Figure 14, p 37) between cells 8 and Di The maximum Z value in cell D is at least greater than 35 dBZ~ but the e 4 km gradient between the BWER and cell D is only 11 dBZ. The ti. lt of the core appears to he to the left... usually are separated by at least 150 km~ while severe thunderstorms frequently are distributed on a much smaller scale Thus~ weather radars, which can scan radial distances greater than 150 km~ serve as the most useful tool to facilitate severe storm...

Radlein, Robin Ann

1977-01-01T23:59:59.000Z

418

Statistical observations of the MLT, latitude and size of pulsed ionospheric ows with the CUTLASS Finland radar  

E-Print Network [OSTI]

Finland radar G. Provan, T. K. Yeoman Department of Physics and Astronomy, University of Leicester as detected by the CUTLASS Finland HF radar. These ¯ows have been suggested as being created scan data from the CUT- LASS Finland radar have been analysed in order to perform a statistical study

Paris-Sud XI, Université de

419

Null vector fields in spaces with affine connections and metrics. Doppler's effect, Hubble's effect, and aberration's effect  

E-Print Network [OSTI]

The notion of null (isotropic) vector field is considered in spaces with affine connections and metrics as models of space or space-time. On its basis the propagation of signals in space-time is considered. The Doppler effect is generalized for these types of spaces. The notions of standard (longitudinal) Doppler effect and transversal Doppler effect are introduced. On their grounds, the Hubble effect and the aberration effect appear as Doppler effects with explicit forms of the centrifugal (centripetal) and Coriolis velocity vector fields in spaces with affine connections and metrics. The upper limit of the value of the general observed shift parameter z, generated by both the effects, based on the Doppler effects, is found to be z = 1.41. Doppler's effects, Hubble's effect, and aberration's effect could be used in mechanics of continuous media and in other classical field theories in the same way as the standard Doppler effect is used in classical and relativistic mechanics. PACS numbers: 04.20.Cv; 04.50.+h; 04.40.b; 04.90.+e; 83.10.Bb

Sawa Manoff

2003-05-07T23:59:59.000Z

420

Phase control of probe response in a Doppler-broadened N-type four-level system  

SciTech Connect (OSTI)

In this paper, we investigate theoretically the effect of the relative phase ({phi}) between the probe and driving fields on gain (absorption) and dispersion of the probe field in a Doppler-broadened N-type four-level system with spontaneously generated coherence from different respects. It is shown that gain (absorption) and dispersion are very sensitive to variations in the relative phase, and changing the Doppler width also has an obvious effect on the phase-dependent gain (absorption) and dispersion. When the probe and driving fields have the same propagation directions (copropagating), for the same Doppler width, the dispersion curve with {phi}={alpha} is the same as the gain (absorption) curve with {phi}={alpha}+{pi}/2; however, when the probe and driving fields have opposite propagation directions (counterpropagating), the dispersion curve and gain (absorption) curve are different and the difference becomes more considerable with an increase in Doppler width. In the co- and counterpropagating cases, gain (absorption) and dispersion always vary periodically with varying {phi}, and the period is 2{pi}. By adjusting the value of {phi}, the largest gain (absorption) and dispersion can be obtained, and a large index of refraction without absorption can be realized. Generally speaking, gain decreases with an increase in Doppler width, but by adjusting value of {phi}, at some special values of Doppler width, a larger gain than that without Doppler broadening can be obtained. Our study also shows that gain in the copropagating case is much larger than that in the counterpropagating case.

Fan Xijun; Liu Zhongbo; Liang Ying; Jia Kening [College of Physics and Electronics, Shandong Normal University, Jinan 250014 (China); Tong Dianmin [School of Physics, Shandong University, Jinan 250100 (China)

2011-04-15T23:59:59.000Z

Note: This page contains sample records for the topic "radar doppler spectra" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

babb-99.PDF  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Constrained Linear Inversion Algorithm Constrained Linear Inversion Algorithm to Retrieve Cloud Properties from the ARM 35-GHz Radar D. M. Babb and J. Verlinde The Pennsylvania State University University Park, Pennsylvania Introduction There are several problems in atmospheric science, particularly in remote sensing, that involve recovering a signal which has been multiplied by a set of overlapping weighting functions. In such cases, the measured signal at a particular point, S ˆ i , is given by ( ) ( ) dj j K j S S ˆ i 0 i ∫ ∞ = (1) where S(j) is the true signal and K i (j) is the i th weighting function evaluated at position j, hereto referred to the kernel function. One example is the broadening of radar Doppler spectra due to turbulent air motions within the radar volume. Doppler spectra, collected from a vertically pointing radar, are a measure of spectral reflectivity per

422

I. I. Rabi, Nuclear Magnetic Resonance (NMR), and Radar  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

I. I. Rabi, Nuclear Magnetic Resonance (NMR), and Radar I. I. Rabi, Nuclear Magnetic Resonance (NMR), and Radar Resources with Additional Information I.I. Rabi Courtesy of Brookhaven National Laboratory 'Isidor Isaac Rabi [was] a pioneer in exploring the atom and a major force in 20th-century physics.'1 He won the 1944 Nobel Prize in Physics "for his resonance method for recording the magnetic properties of atomic nuclei". 'His work in turn made possible the precise measurements necessary for the development of the atomic clock, the laser and the diagnostic scanning of the human body by nuclear magnetic resonance. '1 In 1929, Dr. Rabi started working at Columbia University, where he conducted molecular beam research. However, 'Rabi did not relish the task of coaxing from a departmental chairman or dean even the relatively modest funds needed for molecular beam equipment.'2 When Harold Urey, a professor at Columbia, won the 1934 Nobel Prize in Chemistry for his discovery of deuterium, he also received 'an award from the Carnegie Foundation of about $8,000 to assist his research. Urey had no immediate need of this munificence'2 and gave part of it to Dr. Rabi 'so he could continue his research. By 1937 that research had led him to the technique for which he won his Nobel Prize. '1

423

A comparison of spotlight synthetic aperture radar image formation techniques  

SciTech Connect (OSTI)

Spotlight synthetic aperture radar images can be formed from the complex phase history data using two main techniques: (1) polar-to-cartesian interpolation followed by two-dimensional inverse Fourier transform (2DFFT), and (2) convolution backprojection (CBP). CBP has been widely used to reconstruct medical images in computer aided tomography, and only recently has been applied to form synthetic aperture radar imagery. It is alleged that CBP yields higher quality images because (1) all the Fourier data are used and (2) the polar formatted data is used directly to form a 2D Cartesian image and therefore 2D interpolation is not required. This report compares the quality of images formed by CBP and several modified versions of the 2DFFT method. We show from an image quality point of view that CBP is equivalent to first windowing the phase history data and then interpolating to an exscribed rectangle. From a mathematical perspective, we should expect this conclusion since the same Fourier data are used to form the SAR image. We next address the issue of parallel implementation of each algorithm. We dispute previous claims that CBP is more readily parallelizable than the 2DFFT method. Our conclusions are supported by comparing execution times between massively parallel implementations of both algorithms, showing that both experience similar decreases in computation time, but that CBP takes significantly longer to form an image.

Knittle, C.D.; Doren, N.E.; Jakowatz, C.V.

1996-10-01T23:59:59.000Z

424

Radar Observations of the 2011 October Draconid Outburst  

E-Print Network [OSTI]

A strong outburst of the October Draconid meteor shower was predicted for October 8, 2011. Here we present the observations obtained by the Canadian Meteor Orbit Radar (CMOR) during the 2011 outburst. CMOR recorded 61 multi-station Draconid echoes and 179 single-station overdense Draconid echoes (covering the magnitude range of +3 <= MV <= +7) between 16-20h UT on October 8, 2011. The mean radiant for the outburst was determined to be a_g = 261.9o +/- 0.3o, d_g = +55.3o +/- 0.3o (J2000) from observations of the underdense multi-station echoes. This radiant location agrees with model predictions to ~1o . The determined geocentric velocity was found to be ~10-15% lower than the model value (17.0 - 19.1 km s^-1 versus 20.4 km s^-1), a discrepancy we attribute to undercorrection for atmospheric deceleration of low density Draconid meteoroids as well as to poor radar radiant geometry during the outburst peak. The mass index at the time of the outburst was determined to be ~ 1.75 using the amplitude distribut...

Ye, Quanzhi; Campbell-Brown, Margaret D; Weryk, Robert J

2013-01-01T23:59:59.000Z

425

Excitation-emission spectra and fluorescence quantum yields for...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Excitation-emission spectra and fluorescence quantum yields for fresh and aged biogenic secondary organic aerosols. Excitation-emission spectra and fluorescence quantum yields for...

426

Computational Study of Emitted Spectra from the Neon Plasma Focus  

Science Journals Connector (OSTI)

The expected emission spectra (full, Bremsstrahlung, recombination, and line) of neon focussed plasma have been studied for different conditions. Expected neon plasma spectra at certain electron temperature range...

M. Akel; S. Alsheikh Salo; C. S. Wong

2013-08-01T23:59:59.000Z

427

ARM - Instrument - wacr  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

govInstrumentswacr govInstrumentswacr Documentation WACR : Handbook WACR : Instrument Mentor Monthly Summary (IMMS) reports WACR : Data Quality Assessment (DQA) reports ARM Data Discovery Browse Data Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Instrument : W-Band (95 GHz) ARM Cloud Radar (WACR) Instrument Categories Cloud Properties Latest version W-band ARM cloud radar Latest version W-band ARM cloud radar General Overview The W-band Atmospheric Radiation Measurement (ARM) Program Cloud Radar (WACR) systems are zenith pointing Doppler radars that probe the extent and composition of clouds at 95.04 GHz. The main purpose of this radar is to determine cloud boundaries (e.g., cloud bottoms and tops). This radar reports estimates for the first three spectra moments for each range gate

428

Background noise spectra of global seismic stations  

SciTech Connect (OSTI)

Over an extended period of time station noise spectra were collected from various sources for use in estimating the detection and location performance of global networks of seismic stations. As the database of noise spectra enlarged and duplicate entries became available, an effort was mounted to more carefully select station noise spectra while discarding others. This report discusses the methodology and criteria by which the noise spectra were selected. It also identifies and illustrates the station noise spectra which survived the selection process and which currently contribute to the modeling efforts. The resulting catalog of noise statistics not only benefits those who model network performance but also those who wish to select stations on the basis of their noise level as may occur in designing networks or in selecting seismological data for analysis on the basis of station noise level. In view of the various ways by which station noise were estimated by the different contributors, it is advisable that future efforts which predict network performance have available station noise data and spectral estimation methods which are compatible with the statistics underlying seismic noise. This appropriately requires (1) averaging noise over seasonal and/or diurnal cycles, (2) averaging noise over time intervals comparable to those employed by actual detectors, and (3) using logarithmic measures of the noise.

Wada, M.M.; Claassen, J.P.

1996-08-01T23:59:59.000Z

429

Fast inversion of solar Ca II spectra  

E-Print Network [OSTI]

We present a fast (solar Ca II lines. The code uses an archive of spectra that are synthesized prior to the inversion under the assumption of local thermodynamic equilibrium (LTE). We show that it can be successfully applied to spectrograph data or more sparsely sampled spectra from two-dimensional spectrometers. From a comparison to a non-LTE inversion of the same set of spectra, we derive a first-order non-LTE correction to the temperature stratifications derived in the LTE approach. The correction factor is close to unity up to log tau ~ -3 and increases to values of 2.5 and 4 at log tau = -6 in the quiet Sun and the umbra, respectively.

Beck, C; Rezaei, R; Louis, R E

2014-01-01T23:59:59.000Z

430

A study of radial-flow turbomachinery blade vibration measurements using Eulerian laser Doppler vibrometry  

Science Journals Connector (OSTI)

The structural integrity of blades is critical to the health of turbomachinery. Since operational failure of these blades can possibly lead to catastrophic failure of the machine it is important to have knowledge of blade conditions in an online fashion. Due to several practical implications it is desired to measure blade vibration with a non-contact technique. The application of laser Doppler vibrometry towards the vibration based condition monitoring of axial-flow turbomachinery blades has been successfully demonstrated in previous work. In this paper the feasibility of using laser Doppler vibrometry to measure radial-flow turbomachinery blade vibrations is investigated with the aid of digital image correlation and strain gauge telemetry.

2014-01-01T23:59:59.000Z

431

Impact of the Doppler Broadened Double Differential Cross Section on Observed Resonance Profiles  

Science Journals Connector (OSTI)

Abstract This paper is sequential to studies discussing with the impact of the Doppler broadening of the Double Differential Cross Section (DDXS) on nuclear reactor core calculations. In this study, the influence of the resonance dependent DDXS on the observed resonance line shape in time of flight capture experiments is investigated. The importance of the correct formalism is illustrated by comparing Monte Carlo simulations with and without a resonance dependent DDXS model to measured data of a saturated 238U resonance. The resonance dependent DDXS is taken into account via its stochastic implementation known as Doppler Broadening Rejection Correction (DBRC). In addition, the increased impact of the resonance dependent DDXS model for higher temperatures is shown via a simulation of capture yields for 238U and 183W at different sample temperatures.

R. Dagan; B. Becker; Y. Danon; F. Gunsing; S. Kopecky; C. Lampoudis; O. Litaize; M. Moxon; P. Schillebeeckx

2014-01-01T23:59:59.000Z

432

On the role of spectral resolution in velocity shear layer measurements by Doppler reflectometry  

SciTech Connect (OSTI)

The signal quality of a Doppler reflectometer depends strongly on its spectral resolution, which is influenced by the microwave beam properties and the radius of curvature of the cutoff layer in the plasma. If measured close to a strong perpendicular velocity shear layer, the spectrum of the backscattered signal is influenced by different velocities. This can give rise to two Doppler shifted peaks in the spectrum as observed in TJ-II H-mode plasmas. It is shown by two-dimensional full wave simulations that the two peaks are separable provided the spectral resolution of the system is sufficient. However, if the spectral resolution is poor, the two peaks blend into one and yield an intermediate and incorrect velocity.

Happel, T.; Blanco, E.; Estrada, T. [Laboratorio Nacional de Fusion, Association Euratom-Ciemat, 28040 Madrid (Spain)

2010-10-15T23:59:59.000Z

433

Doppler Effects from Bending of Light Rays in Curved Space-Times  

E-Print Network [OSTI]

We study Doppler effects in curved space-time, i.e. the frequency shifts induced on electromagnetic signals propagating in the gravitational field. In particular, we focus on the frequency shift due to the bending of light rays in weak gravitational fields. We consider, using the PPN formalism, the gravitational field of an axially symmetric distribution of mass. The zeroth order, i.e. the sphere, is studied then passing to the contribution of the quadrupole moment, and finally to the case of a rotating source. We give numerical estimates for situations of physical interest, and by a very preliminary analysis, we argue that analyzing the Doppler effect could lead, in principle, in the foreseeable future, to the measurement of the quadrupole moment of the giant planets of the Solar System.

Matteo Luca Ruggiero; Angelo Tartaglia; Lorenzo Iorio

2006-05-06T23:59:59.000Z

434

Doppler- and recoil-free laser excitation of Rydberg states via three-photon transitions  

SciTech Connect (OSTI)

Three-photon laser excitation of Rydberg states by three different laser beams can be arranged in a starlike geometry that simultaneously eliminates the recoil effect and Doppler broadening. Our analytical and numerical calculations for a particular laser excitation scheme 5S{sub 1/2}{yields}5P{sub 3/2}{yields}6S{sub 1/2}{yields}nP in Rb atoms have shown that, compared to the one- and two-photon laser excitation, this approach provides much narrower linewidth and longer coherence time for both cold atom samples and hot vapors, if the intermediate one-photon resonances of the three-photon transition are detuned by more than respective single-photon Doppler widths. This method can be used to improve fidelity of Rydberg quantum gates and precision of spectroscopic measurements in Rydberg atoms.

Ryabtsev, I. I.; Beterov, I. I.; Tretyakov, D. B.; Entin, V. M.; Yakshina, E. A. [A. V. Rzhanov Institute of Semiconductor Physics SB RAS, Prospekt Lavrentyeva 13, 630090 Novosibirsk (Russian Federation)

2011-11-15T23:59:59.000Z

435

Doppler cooling with coherent trains of laser pulses and a tunable velocity comb  

SciTech Connect (OSTI)

We explore the possibility of decelerating and Doppler cooling an ensemble of two-level atoms by a coherent train of short, nonoverlapping laser pulses. We derive analytical expressions for mechanical force exerted by the train. In frequency space the force pattern reflects the underlying frequency comb structure. The pattern depends strongly on the ratio of the atomic lifetime to the repetition time between the pulses and pulse area. For example, in the limit of short lifetimes, the frequency-space peaks of the optical force wash out. We propose to tune the carrier-envelope offset frequency to follow the Doppler-shifted detuning as atoms decelerate; this leads to compression of atomic velocity distribution about comb teeth and results in a ''velocity comb''--a series of narrow equidistant peaks in the velocity space.

Ilinova, Ekaterina; Ahmad, Mahmoud; Derevianko, Andrei [Department of Physics, University of Nevada, Reno, Nevada 89557 (United States)

2011-09-15T23:59:59.000Z

436

3-D laser Doppler velocimetry study of incompressible flow through an orifice plate  

E-Print Network [OSTI]

of Advisory Committee: Dr. Gerald Morrison Orifice meters are used extensively in the U. S. for the measurement of natural gas. Uncertainty of metering accuracy has resulted in an estimated 250 million dollars annually in mis-charges. This has led... to the need for basic research on orifice meters in an attempt to improve the accuracy of existing metering facilities. The objective of this present study was to use a 3-D LDV (laser Doppler velocimeter) to obtain detailed velocity and turbulence...

Panak, David Leo

2012-06-07T23:59:59.000Z

437

On the Doppler effect for light from orbiting sources in Kerr-type metrics  

E-Print Network [OSTI]

A formula is derived for the combined motional and gravitational Doppler effect in general stationary axisymmetric metrics for a photon emitted parallel or antiparallel to the assumed circular orbital motion of its source. The same formula is derived from eikonal approximation and Killing vector approaches to elucidate connections between observational astronomy and modern Relativity. The formula yields expected results in the limits of a moving or stationary source in the exterior Kerr and Schwarzschild metrics and a moving source in flat space.

S. Cisneros; G. Goedecke; C. Beetle; M. Engelhardt

2012-03-12T23:59:59.000Z

438

Synthetic Lorentz force in classical atomic gases via Doppler effect and radiation pressure  

E-Print Network [OSTI]

We theoretically predict a novel type of synthetic Lorentz force for classical (cold) atomic gases, which is based on the Doppler effect and radiation pressure. A fairly uniform and strong force can be constructed for gases in macroscopic volumes of several cubic millimeters and more. This opens the possibility to mimic classical charged gases in magnetic fields, such as those in a tokamak, in cold atom experiments.

Dub?ek, T; Juki?, D; Aumiler, D; Ban, T; Buljan, H

2014-01-01T23:59:59.000Z

439

Doppler effects of an oscillating line source in shear flow with a free surface  

Science Journals Connector (OSTI)

Abstract The linearised water-wave radiation problem for the oscillating 2D submerged source in an inviscid shear flow with a free surface is investigated analytically. There is a nonzero surface velocity. The depth is infinite and the vorticity is uniform. The amplitudes radiated from the source are calculated analytically. Due to Doppler effects, there may be up to four different emitted waves, and there is resonance with zero group velocity and infinite amplitude.

Peder A. Tyvand; Mikkel Elle Lepperød

2014-01-01T23:59:59.000Z

440

CONSTRAINING HIGH-SPEED WINDS IN EXOPLANET ATMOSPHERES THROUGH OBSERVATIONS OF ANOMALOUS DOPPLER SHIFTS DURING TRANSIT  

SciTech Connect (OSTI)

Three-dimensional (3D) dynamical models of hot Jupiter atmospheres predict very strong wind speeds. For tidally locked hot Jupiters, winds at high altitude in the planet's atmosphere advect heat from the day side to the cooler night side of the planet. Net wind speeds on the order of 1-10 km s{sup -1} directed towards the night side of the planet are predicted at mbar pressures, which is the approximate pressure level probed by transmission spectroscopy. These winds should result in an observed blueshift of spectral lines in transmission on the order of the wind speed. Indeed, Snellen et al. recently observed a 2 {+-} 1 km s{sup -1} blueshift of CO transmission features for HD 209458b, which has been interpreted as a detection of the day-to-night (substellar to anti-stellar) winds that have been predicted by 3D atmospheric dynamics modeling. Here, we present the results of a coupled 3D atmospheric dynamics and transmission spectrum model, which predicts the Doppler-shifted spectrum of a hot Jupiter during transit resulting from winds in the planet's atmosphere. We explore four different models for the hot Jupiter atmosphere using different prescriptions for atmospheric drag via interaction with planetary magnetic fields. We find that models with no magnetic drag produce net Doppler blueshifts in the transmission spectrum of {approx}2 km s{sup -1} and that lower Doppler shifts of {approx}1 km s{sup -1} are found for the higher drag cases, results consistent with-but not yet strongly constrained by-the Snellen et al. measurement. We additionally explore the possibility of recovering the average terminator wind speed as a function of altitude by measuring Doppler shifts of individual spectral lines and spatially resolving wind speeds across the leading and trailing terminators during ingress and egress.

Miller-Ricci Kempton, Eliza [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Rauscher, Emily, E-mail: ekempton@ucolick.org [Lunar and Planetary Laboratory, University of Arizona, 1629 East University Boulevard, Tucson, AZ 85721 (United States)

2012-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "radar doppler spectra" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Noninvasive Monitoring of Vocal Fold Vertical Vibration Using The Acoustic Doppler Effect  

Science Journals Connector (OSTI)

SummaryObjectives/Hypothesis To validate a proposed method of noninvasively monitoring vocal fold vertical vibration through utilization of the acoustic Doppler effect and the waveguide property of the vocal tract. Study Design Validation case-control study. Methods In this device, an ultrasound beam is generated and directed into the mouth. The vocal tract, acting as a natural waveguide, guides the ultrasound beam toward the vibrating vocal folds. The vertical velocity of vocal fold vibration is then recovered from the Doppler frequency of the reflected ultrasound. One subject (age 32, male) was studied and measurements were taken under three modes of vocal fold vibration: breathing (no vibration), whispering (irregular vibration), and normal phonation (regular vibration). Results The peak-to-peak amplitude of the measured velocity of vocal fold vertical vibration was about 0.16 m/s, and the fundamental frequency was 172 Hz; the extracted velocity information showed a reasonable waveform and value in comparison with the previous studies. In all three modes of phonation, the Doppler frequencies derived from the reflected ultrasound corresponded with the vertical velocity of vocal fold vibration as expected. Conclusions The proposed method can accurately represent the characteristics of different phonation modes such as no phonation, whisper and normal phonation. The proposed device could be used in daily monitoring and assessment of vocal function and vocal fold vibration.

Chao Tao; Jack J. Jiang; Dan Wu; Xiaojun Liu; Ann Chodara

2012-01-01T23:59:59.000Z

442

Doppler effects in heterogeneous media with applications to ocean acoustic modeling  

Science Journals Connector (OSTI)

Doppler shift corrections to ocean acoustic signals are complicated by the multi-spatial-scale structure of the ocean medium, resulting in a multi-time-scale structure of the acoustic Green function. Repeated reflections and refractions lead in general to an infinite number of acoustic paths or modes, with different times of flight, connecting source and receiver. The rate of change of these flight times with source or receiver motion gives rise to Doppler shift corrections, and each acoustic path or mode has a different correction. A clean Doppler correction (in the sense of an observable coherent motion-induced frequency shift for each path or mode) is shown to emerge only when the medium is homogeneous along the direction of source or receiver motion, even when it is highly inhomogeneous in directions orthogonal to the motion. A very general quantitative theory for this correction is developed, encompassing earlier results in the literature, and presented in a form amenable to efficient numerical implementation in data processing.

Peter B. Weichman

2005-12-06T23:59:59.000Z

443

Linear and nonlinear light propagations in a Doppler-broadened medium via electromagnetically induced transparency  

SciTech Connect (OSTI)

We present a systematic theoretical study to deal with linear and nonlinear light propagations in a Doppler-broadened three-level {Lambda} system via electromagnetically induced transparency (EIT), with incoherent population exchange between two lower energy levels taken into account. Through a careful analysis of base state and linear excitation, we show that the EIT condition of the system is given by |{Omega}{sub c}|{sup 2{gamma}}{sub 31}>>2{gamma}{sub 21{Delta}{omega}D}{sup 2}, where {Omega}{sub c} is half the Rabi frequency of the control field, {Delta}{omega}{sub D} is the Doppler width, and {gamma}{sub jl} is the decay rate of the coherence between states |j> and |l>. Under this condition, the effect of incoherent population exchange is insignificant, while dephasing dominates the decoherence of the system. This condition also ensures the validity of the weak nonlinear perturbation theory used in this work for solving the Maxwell-Bloch equations with inhomogeneous broadening. We then investigate the nonlinear propagation of the probe field and show that it is possible to form temporal optical solitons in the Doppler-broadened medium. Such solitons have ultraslow propagating velocity and can be generated in very low light power. The possibility of realizing (1+1)-dimensional and (2+1)-dimensional spatial optical solitons in the adiabatic regime of the system is also discussed.

Li Liang; Huang Guoxiang [Department of Physics and Institute of Theoretical Physics, East China Normal University, Shanghai 200062 (China); State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China and Institute of Nonlinear Physics, Zhejiang Normal University, Zhejiang 321004 (China)

2010-08-15T23:59:59.000Z

444

Method and apparatus for optical Doppler tomographic imaging of fluid flow velocity in highly scattering media  

DOE Patents [OSTI]

Optical Doppler tomography permits imaging of fluid flow velocity in highly scattering media. The tomography system combines Doppler velocimetry with high spatial resolution of partially coherent optical interferometry to measure fluid flow velocity at discrete spatial locations. Noninvasive in vivo imaging of blood flow dynamics and tissue structures with high spatial resolutions of the order of 2 to 10 microns is achieved in biological systems. The backscattered interference signals derived from the interferometer may be analyzed either through power spectrum determination to obtain the position and velocity of each particle in the fluid flow sample at each pixel, or the interference spectral density may be analyzed at each frequency in the spectrum to obtain the positions and velocities of the particles in a cross-section to which the interference spectral density corresponds. The realized resolutions of optical Doppler tomography allows noninvasive in vivo imaging of both blood microcirculation and tissue structure surrounding the vessel which has significance for biomedical research and clinical applications.

Nelson, John Stuart (Laguna Niguel, CA); Milner, Thomas Edward (Irvine, CA); Chen, Zhongping (Irvine, CA)

1999-01-01T23:59:59.000Z

445

Improved algorithms for the calculation of resolved resonance cross sections with applications to the structural Doppler effect in fast reactors  

SciTech Connect (OSTI)

Motivated by a need for an economical yet rigorous tool which can address the computation of the structural material Doppler effect, an extremely efficient improved RABANL capability has been developed utilizing the fact that the Doppler broadened line shape functions become essentially identical to the natural line shape functions or Lorentzian limits beyond about 100 Doppler widths from the resonance energy, or when the natural width exceeds about 200 Doppler widths. The computational efficiency has been further enhanced by preprocessing or screening a significant number of selected resonances during library preparation into composition and temperature independent smooth background cross sections. The resonances which are suitable for such pre-processing are those which are either very broad or those which are very weak. The former contribute very little to the Doppler effect and their self-shielding effect can readily be averaged into slowly varying background cross section data, while the latter contribute very little to either the Doppler or to self-shielding effects. To illustrate the accuracy and efficiency of the improved RABANL algorithms and resonance screening techniques, calculations have been performed for two systems, the first with a composition typical of the STF converter region and the second typical of an LMFBR core composition. Excellent agreement has been found for RABANL compared to the reference Monte Carlo solution obtained using the code VIM, and improved results have also been obtained for the narrow resonance approximation in the ultra-fine-group option of MC/sup 2/-2.

Hwang, R.N.; Toppel, B.J.; Henryson, H. II

1980-10-01T23:59:59.000Z

446

Ultra-wideband short-pulse radar with range accuracy for short range detection  

DOE Patents [OSTI]

An ultra-wideband (UWB) radar transmitter apparatus comprises a pulse generator configured to produce from a sinusoidal input signal a pulsed output signal having a series of baseband pulses with a first pulse repetition frequency (PRF). The pulse generator includes a plurality of components that each have a nonlinear electrical reactance. A signal converter is coupled to the pulse generator and configured to convert the pulsed output signal into a pulsed radar transmit signal having a series of radar transmit pulses with a second PRF that is less than the first PRF.

Rodenbeck, Christopher T; Pankonin, Jeffrey; Heintzleman, Richard E; Kinzie, Nicola Jean; Popovic, Zorana P

2014-10-07T23:59:59.000Z

447

CALCULATION OF ION ENERGY-DEPOSITION SPECTRA  

E-Print Network [OSTI]

CALCULATION OF ION ENERGY-DEPOSITION SPECTRA IN SILICON, LITHIUM-FLUORIDE, BORON, AND BORON CARBIDE by J.K. Shultis and D.S. McGregor Department of Mechanical and Nuclear Engineering Kansas State University Manhattan, Kansas 55606 published as Report 299 ENGINEERING EXPERIMENT STATION College

Shultis, J. Kenneth

448

Generator-coordinate theory of molecular spectra  

Science Journals Connector (OSTI)

We review the merits and shortcomings of the Born-Oppenheimer separation and suggest a nonadiabatic approach to molecular spectra using the generator-coordinate method. The adiabatic approximation and the new scheme are worked out in parallel for diatomic molecules.

Luc Lathouwers

1978-11-01T23:59:59.000Z

449

Iterative Self-Dual Reconstruction on Radar Image Recovery  

SciTech Connect (OSTI)

Imaging systems as ultrasound, sonar, laser and synthetic aperture radar (SAR) are subjected to speckle noise during image acquisition. Before analyzing these images, it is often necessary to remove the speckle noise using filters. We combine properties of two mathematical morphology filters with speckle statistics to propose a signal-dependent noise filter to multiplicative noise. We describe a multiscale scheme that preserves sharp edges while it smooths homogeneous areas, by combining local statistics with two mathematical morphology filters: the alternating sequential and the self-dual reconstruction algorithms. The experimental results show that the proposed approach is less sensitive to varying window sizes when applied to simulated and real SAR images in comparison with standard filters.

Martins, Charles; Medeiros, Fatima; Ushizima, Daniela; Bezerra, Francisco; Marques, Regis; Mascarenhas, Nelson

2010-05-21T23:59:59.000Z

450

Phase coded, micro-power impulse radar motion sensor  

DOE Patents [OSTI]

A motion sensing, micro-power impulse radar MIR impresses on the transmitted signal, or the received pulse timing signal, one or more frequencies lower than the pulse repetition frequency, that become intermediate frequencies in a "IF homodyne" receiver. Thus, many advantages of classical RF receivers can be thereby be realized with ultra-wide band radar. The sensor includes a transmitter which transmits a sequence of electromagnetic pulses in response to a transmit timing signal at a nominal pulse repetition frequency. A receiver samples echoes of the sequence of electromagnetic pulses from objects within the field with controlled timing, in response to a receive timing signal, and generates a sample signal in response to the samples. A timing circuit supplies the transmit timing signal to the transmitter and supplies the receive timing signal to the receiver. The relative timing of the transmit timing signal and the receive timing signal is modulated between a first relative delay and a second relative delay at an intermediate frequency, causing the receiver to sample the echoes such that the time between transmissions of pulses in the sequence and samples by the receiver is modulated at the intermediate frequency. Modulation may be executed by modulating the pulse repetition frequency which drives the transmitter, by modulating the delay circuitry which controls the relative timing of the sample strobe, or by modulating amplitude of the transmitted pulses. The electromagnetic pulses will have a nominal center frequency related to pulse width, and the first relative delay and the second relative delay between which the timing signals are modulated, differ by less than the nominal pulse width, and preferably by about one-quarter wavelength at the nominal center frequency of the transmitted pulses.

McEwan, Thomas E. (Livermore, CA)

1996-01-01T23:59:59.000Z

451

Lightning and radar observations of hurricane Rita landfall  

SciTech Connect (OSTI)

Los Alamos National Laboratory (LANL) owns and operates an array of Very-Low Frequency (VLF) sensors that measure the Radio-Frequency (RF) waveforms emitted by Cloud-to-Ground (CG) and InCloud (IC) lightning. This array, the Los Alamos Sferic Array (LASA), has approximately 15 sensors concentrated in the Great Plains and Florida, which detect electric field changes in a bandwidth from 200 Hz to 500 kHz (Smith et al., 2002). Recently, LANL has begun development of a new dual-band RF sensor array that includes the Very-High Frequency (VHF) band as well as the VLF. Whereas VLF lightning emissions can be used to deduce physical parameters such as lightning type and peak current, VHF emissions can be used to perform precise 3d mapping of individual radiation sources, which can number in the thousands for a typical CG flash. These new dual-band sensors will be used to monitor lightning activity in hurricanes in an effort to better predict intensification cycles. Although the new LANL dual-band array is not yet operational, we have begun initial work utilizing both VLF and VHF lightning data to monitor hurricane evolution. In this paper, we present the temporal evolution of Rita's landfall using VLF and VHF lightning data, and also WSR-88D radar. At landfall, Rita's northern eyewall experienced strong updrafts and significant lightning activity that appear to mark a transition between oceanic hurricane dynamics and continental thunderstorm dynamics. In section 2, we give a brief overview of Hurricane Rita, including its development as a hurricane and its lightning history. In the following section, we present WSR-88D data of Rita's landfall, including reflectivity images and temporal variation. In section 4, we present both VHF and VLF lightning data, overplotted on radar reflectivity images. Finally, we discuss our observations, including a comparison to previous studies and a brief conclusion.

Henderson, Bradley G [Los Alamos National Laboratory; Suszcynsky, David M [Los Alamos National Laboratory; Hamlin, Timothy E [Los Alamos National Laboratory; Jeffery, C A [Los Alamos National Laboratory; Wiens, Kyle C [TEXAS TECH U.; Orville, R E [TEXAS A& M

2009-01-01T23:59:59.000Z

452

Improved Predictions of Reactor Antineutrino Spectra  

E-Print Network [OSTI]

We report new calculations of reactor antineutrino spectra including the latest information from nuclear databases and a detailed error budget. The first part of this work is the so-called ab initio approach where the total antineutrino spectrum is built from the sum of all beta-branches of all fission products predicted by an evolution code. Systematic effects and missing information in nuclear databases lead to final relative uncertainties in the 10 to 20% range. A prediction of the antineutrino spectrum associated with the fission of 238U is given based on this ab initio method. For the dominant isotopes 235U and 239Pu, we developed a more accurate approach combining information from nuclear databases and reference electron spectra associated with the fission of 235U, 239Pu and 241Pu, measured at ILL in the 80's. We show how the anchor point of the measured total beta-spectra can be used to suppress the uncertainty in nuclear databases while taking advantage of all the information they contain. We provide new reference antineutrino spectra for 235U, 239Pu and 241Pu isotopes in the 2-8 MeV range. While the shapes of the spectra and their uncertainties are comparable to that of the previous analysis of the ILL data, the normalization is shifted by about +3% on average. In the perspective of the re-analysis of past experiments and direct use of these results by upcoming oscillation experiments, we discuss the various sources of errors and their correlations as well as the corrections induced by off equilibrium effects.

Th. A. Mueller; D. Lhuillier; M. Fallot; A. Letourneau; S. Cormon; M. Fechner; L. Giot; T. Lasserre; J. Martino; G. Mention; A. Porta; F. Yermia

2011-01-13T23:59:59.000Z

453

ARM - Publications: Science Team Meeting Documents: W-Band ARM Cloud Radar  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

W-Band ARM Cloud Radar System W-Band ARM Cloud Radar System Mead, James ProSensing Inc. Widener, Kevin Pacific Northwest National Laboratory The W-Band ARM Cloud Radar (WACR) is a dual polarization 95 GHz radar that will be deployed at the SGP CART site in the spring of 2005. The WACR system will be installed in the existing MMCR shelter, and will provide continuous zenith pointing measurements of clouds to compliment measurements provided by MMCR. Built by ProSensing Inc. of Amherst, MA, the WACR system include a high peak power (1.5 kW) EIKA transmitter, low noise receiver, and PC-based digital receiver. In addition to an internal calibration procedure, an electronically controlled deflector plate mounted on the roof of the MMCR shelter will be used to periodically illuminate a

454

B61-12 Life Extension Program Radar Drop Tests Completed Successfully |  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

B61-12 Life Extension Program Radar Drop Tests Completed Successfully | B61-12 Life Extension Program Radar Drop Tests Completed Successfully | National Nuclear Security Administration Our Mission Managing the Stockpile Preventing Proliferation Powering the Nuclear Navy Emergency Response Recapitalizing Our Infrastructure Continuing Management Reform Countering Nuclear Terrorism About Us Our Programs Our History Who We Are Our Leadership Our Locations Budget Our Operations Media Room Congressional Testimony Fact Sheets Newsletters Press Releases Speeches Events Social Media Video Gallery Photo Gallery NNSA Archive Federal Employment Apply for Our Jobs Our Jobs Working at NNSA Blog Home > Media Room > Press Releases > B61-12 Life Extension Program Radar Drop Tests ... Press Release B61-12 Life Extension Program Radar Drop Tests Completed Successfully

455

Ground penetrating radar characterization of wood piles and the water table in Back Bay, Boston  

E-Print Network [OSTI]

Ground penetrating radar (GPR) surveys are performed to determine the depth to the water table and the tops of wood piles beneath a residential structure at 122 Beacon Street in Back Bay, Boston. The area of Boston known ...

LeFrançois, Suzanne O'Neil, 1980-

2003-01-01T23:59:59.000Z

456

Impacts of Raindrop Fall Velocity and Axis Ratio Errors on Dual-Polarization Radar Rainfall Estimation  

Science Journals Connector (OSTI)

Motivated by the field observations of fall velocity and axis ratio deviations from predicted terminal velocity and equilibrium axis ratio values, the combined effects of raindrop fall velocity and axis ratio deviations on dual-polarization radar ...

Bin Pei; Firat Y. Testik; Mekonnen Gebremichael

2014-10-01T23:59:59.000Z

457

Ground Clutter Mitigation for Weather Radars Using the Autocorrelation Spectral Density  

Science Journals Connector (OSTI)

Radar returns from the ground, known as ground clutter, can contaminate weather signals, often resulting in severely biased meteorological estimates. If not removed, these contaminants may artificially inflate quantitative precipitation estimates ...

Sebastián M. Torres; David A. Warde

2014-10-01T23:59:59.000Z

458

Analog FIR Filter Used for Range-Optimal Pulsed Radar Applications  

E-Print Network [OSTI]

of implementing the matched filter with an analog FIR filter is proposed. The FIR filter provides a linear phase response which is suitable for radar applications. Analog FIR filters can be implemented in the discrete domain, requiring operational amplifiers...

Su, Eric Chen

2014-08-13T23:59:59.000Z

459

Interagency Field Test Evaluates Co-operation of Turbines and Radar  

Broader source: Energy.gov [DOE]

The Department of Energy and federal agency partners recently completed the first in a series of three radar technology field tests and demonstrations. The Interagency Field Test and Evaluation of...

460

A model for forming airborne synthetic aperture radar images of underground targets  

SciTech Connect (OSTI)

Synthetic Aperture Radar (SAR) from an airborne platform has been proposed for imaging targets beneath the earth`s surface. The propagation of the radar`s energy within the ground, however, is much different than in the earth`s atmosphere. The result is signal refraction, echo delay, propagation losses, dispersion, and volumetric scattering. These all combine to make SAR image formation from an airborne platform much more challenging than a surface imaging counterpart. This report treats the ground as a lossy dispersive half-space, and presents a model for the radar echo based on measurable parameters. The model is then used to explore various imaging schemes, and image properties. Dynamic range is discussed, as is the impact of loss on dynamic range. Modified window functions are proposed to mitigate effects of sidelobes of shallow targets overwhelming deeper targets.

Doerry, A.W.

1994-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "radar doppler spectra" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

Microwave Properties of Ice-Phase Hydrometeors for Radar and Radiometers: Sensitivity to Model Assumptions  

Science Journals Connector (OSTI)

A simplified framework is presented for assessing the qualitative sensitivities of computed microwave properties, satellite brightness temperatures, and radar reflectivities to assumptions concerning the physical properties of ice-phase ...

Benjamin T. Johnson; Grant W. Petty; Gail Skofronick-Jackson

2012-12-01T23:59:59.000Z

462

Stratiform and Convective Precipitation Observed by Multiple Radars during the DYNAMO/AMIE Experiment  

Science Journals Connector (OSTI)

In this study, methods of convective/stratiform precipitation classification and surface rain-rate estimation based on the Atmospheric Radiation Measurement Program (ARM) cloud radar measurements were developed and evaluated. Simultaneous and ...

Min Deng; Pavlos Kollias; Zhe Feng; Chidong Zhang; Charles N. Long; Heike Kalesse; Arunchandra Chandra; Vickal V. Kumar; Alain Protat

2014-11-01T23:59:59.000Z

463

Predictor Variables of the Maximum Radar Echo Activity on Convective Days  

Science Journals Connector (OSTI)

Digital radar data and atmospheric sounding information were analyzed with the intention of beginning a search for atmospheric parameters which are easily attainable, are independent of whether or not clouds are seeded, and either individually or ...

Gerard E. Klazura; Robert G. Pritchard

1980-03-01T23:59:59.000Z

464

An Analysis of Depolarization of Circular Polarization in S-Band Radar Sensing of Alberta Storms  

Science Journals Connector (OSTI)

An analysis is given of storm events in 1982–85 in which the Alberta Research Council circularly polarized polarization diversity S-band radar recorded data indicating significant depolarization. The accompanying two-way differential propagation ...

Anthony R. Holt

2001-09-01T23:59:59.000Z

465

On the Feasibility of Precisely Measuring the Properties of a Precipitating Cloud with a Weather Radar  

E-Print Network [OSTI]

In this paper the results of an investigation are presented that are concerned with the feasibility of employing a weather radar to make precise measurements of the properties of a precipitating cloud. A schematic cloud is proposed as a model...

Runnels, R.C.

466

Consistent patterns of Antarctic ice sheet interannual variations from ENVISAT radar altimetry and GRACE satellite gravimetry  

Science Journals Connector (OSTI)

......radar altimetry and GRACE satellite gravimetry Martin Horwath...regional atmospheric modelling. Satellite altimetry and satellite gravimetry...Centre for Medium-Range Weather Forecasts) variations of...though ENVISAT RA and GRACE satellite gravimetry have their specific......

Martin Horwath; Benoît Legrésy; Frédérique Rémy; Fabien Blarel; Jean-Michel Lemoine

2012-05-01T23:59:59.000Z

467

Evaluation of Precipitation from Numerical Weather Prediction Models and Satellites Using Values Retrieved from Radars  

Science Journals Connector (OSTI)

Precipitation is evaluated from two weather prediction models and satellites, taking radar-retrieved values as a reference. The domain is over the central and eastern United States, with hourly accumulated precipitation over 21 days for the ...

Slavko Vasi?; Charles A. Lin; Isztar Zawadzki; Olivier Bousquet; Diane Chaumont

2007-11-01T23:59:59.000Z

468

Ground penetrating radar technique to locate coal mining related features: case studies in Texas  

E-Print Network [OSTI]

The goal of this research project is to identify the efficacy of the ground penetrating radar (GPR) technique in locating underground coal mine related subsidence features at Malakoff and Bastrop, Texas. The work at Malakoff has been done...

Save, Neelambari R

2006-04-12T23:59:59.000Z

469

Wind-speed inversion from HF radar first-order backscatter signal  

Science Journals Connector (OSTI)

Land-based high-frequency (HF) radars have the unique capability of continuously monitoring ocean surface environments at ranges up to 200 km off the coast. They provide reliable data on ocean surface currents an...

Wei Shen; Klaus-Werner Gurgel; George Voulgaris; Thomas Schlick…

2012-01-01T23:59:59.000Z

470

A Pulse Compression Waveform for Improved-Sensitivity Weather Radar Observations  

Science Journals Connector (OSTI)

The progression of phased array weather observations, research, and planning over the past decade has led to significant advances in development efforts for future weather radar technologies. However, numerous challenges still remain for large-...

James M. Kurdzo; Boon Leng Cheong; Robert D. Palmer; Guifu Zhang; John B. Meier

2014-12-01T23:59:59.000Z

471

Measuring a Utility-Scale Turbine Wake Using the TTUKa Mobile Research Radars  

Science Journals Connector (OSTI)

Observations of the wake generated by a single utility-scale turbine and collected by the Texas Tech University Ka-band mobile research radars on 27 October 2011 are introduced. Remotely sensed turbine wake observations using lidar technology have ...

Brian D. Hirth; John L. Schroeder; W. Scott Gunter; Jerry G. Guynes

2012-06-01T23:59:59.000Z

472

O{sub 2} rotational temperature measurements in an atmospheric air microdischarge by radar resonance-enhanced multiphoton ionization  

SciTech Connect (OSTI)

Nonintrusive spatially resolved rotational temperature measurements in an atmospheric air microdischarge are presented. The measurements were based on coherent microwave Rayleigh scattering (Radar) from resonance-enhanced multiphoton ionization of molecular oxygen. The open air DC microdischarge source operated in a stable 'normal-glow' mode and pin-to-pin electrodes spaced 1.3 mm apart. The second harmonic of a tunable dye laser beam was focused between the two electrodes and scanned between 286 and 288 nm. Coherent microwave Rayleigh scattering was used to collect the two-photon rotational spectra of O{sub 2} at C{sup 3}{Pi}(v = 2) Leftwards-Arrow X{sup 3}{Sigma}(v Prime = 0) transitions. The Boltzmann plots from analyses of the O{sub 2} rotational lines determined local rotational temperatures at various axial locations between the electrodes. The molecular oxygen rotational temperature varied from {approx}1150 K to {approx}1350 K within the discharge area. The measurements had an accuracy of {approx}{+-}50 K.

Sawyer, Jordan; Wu, Yue; Zhang, Zhili [Department of Mechanical, Aerospace and Biomedical Engineering, University of Tennessee, Knoxville Tennessee 37996 (United States)] [Department of Mechanical, Aerospace and Biomedical Engineering, University of Tennessee, Knoxville Tennessee 37996 (United States); Adams, Steven F. [Air Force Research Laboratory (AFRL/RQQE), Wright-Patterson AFB, Ohio 45433-7919 (United States)] [Air Force Research Laboratory (AFRL/RQQE), Wright-Patterson AFB, Ohio 45433-7919 (United States)

2013-06-21T23:59:59.000Z

473

Off-The-Grid X-band Weather Radar Network for the West  

E-Print Network [OSTI]

­ Industry ­ Government · UPRM, UMASS, OU and CSU #12;10,000 ft tornado wind snow 3.05km 04080120160200240 Radar Radar Specifications: · Furuno Marine Based · Frequency = 9.41 GHz · Peak Power = 4 kW / 25 k #12;Results #12;August 29, 2010 #12;Advantages · Low Cost ­ Almost 10 times cheaper than current · Low

Gilbes, Fernando

474

Thickness estimation of subsurface layers in asphalt pavement using monstatic ground penetrating radar  

E-Print Network [OSTI]

THICKNESS ESTIMATION OF SUBSURFACE LAYERS IN ASPHALT PAVEMENT USING MONSTATIC GROUND PENETRATING RADAR A Thesis CHUN LOK LAU Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements... for the degree of MASTER OF SCIENCE December 1991 Major Subject: Electrical Engineering THICKNESS ESTIMATION OF SUBSURFACE LAYERS IN ASPHALT PAVEMENT USING MONSTATIC GROUND PENETRATING RADAR A Thesis CHUN LOK LAU Approved as to style and content by...

Lau, Chun Lok

2012-06-07T23:59:59.000Z

475

Tin City Long Range Radar Station Wind Farm | Open Energy Information  

Open Energy Info (EERE)

Tin City Long Range Radar Station Wind Farm Tin City Long Range Radar Station Wind Farm Jump to: navigation, search Name Tin City Long Range Radar Station Wind Farm Facility Tin City Long Range Radar Station Sector Wind energy Facility Type Community Wind Facility Status In Service Owner Tin City Long Range Radar Station Developer Tanadgusix Corp. Energy Purchaser Tin City Long Range Radar Station Location Nome AK Coordinates 65.559372°, -167.949686° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":65.559372,"lon":-167.949686,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}

476

ARM - Datastreams - wacrspeccmaskcopol  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Datastreamswacrspeccmaskcopol Datastreamswacrspeccmaskcopol Documentation Data Quality Plots Citation DOI: 10.5439/1025318 [ What is this? ] Generate Citation ARM Data Discovery Browse Data Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Datastream : WACRSPECCMASKCOPOL W-band (95 GHz) ARM Cloud Radar, filtered spectral data, co-polarized mode Active Dates 2006.03.24 - 2013.06.14 Measurement Categories Cloud Properties Originating Instrument W-Band (95 GHz) ARM Cloud Radar (WACR) Measurements Only measurements considered scientifically relevant are shown below by default. Show all measurements Measurement Units Variable Locator Mask for Spectra unitless LocatorMask ( time, heights ) Radar Doppler Mean Doppler Velocity m/s MeanDopplerVelocity ( time, heights )

477

Measurement and interpretation of plutonium spectra  

SciTech Connect (OSTI)

The atomic spectroscopic data available for plutonium are among the rickest of any in the periodic system. They include high-resolution grating and Fourier-transform spectra as well as extensive Zeeman and isotope-shift studies. We summarize the present status of the term analysis and cite the configurations that have been identified. A least-squares adjustment of a parametric Hamiltonian for configurations of both Pu I and Pu II has shown that almost all of the expected low levels are now known. The use of a model Hamiltonian applicable to both lanthanide and actinide atomic species has been applied to the low configurations of Pu I and Pu II making use of trends predicted by ab initio calculations. This same model has been used to describe the energy levels of Pu/sup 3 +/ in LaCl/sub 3/, and an extension has permitted preliminary calculations of the spectra of other valence states.

Blaise, J.; Fred, M.S.; Carnall, W.T.; Crosswhite, H.M.; Crosswhite, H.

1982-01-01T23:59:59.000Z

478

The Status of the ACRF Millimeter Wave Cloud Radars (MMCRs), the Path Forward for Future MMCR Upgrades, the Concept of 3D Volume Imaging Radar and the UAV Radar  

SciTech Connect (OSTI)

The United States (U.S.) Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility (ACRF) operates millimeter wavelength cloud radars (MMCRs) in several climatological regimes. The MMCRs, are the primary observing tool for quantifying the properties of nearly all radiatively important clouds over the ACRF sites. The first MMCR was installed at the ACRF Southern Great Plains (SGP) site nine years ago and its original design can be traced to the early 90s. Since then, several MMCRs have been deployed at the ACRF sites, while no significant hardware upgrades have been performed. Recently, a two-stage upgrade (first C-40 Digital Signal Processors [DSP]-based, and later the PC-Integrated Radar AcQuisition System [PIRAQ-III] digital receiver) of the MMCR signal-processing units was completed. Our future MMCR related goals are: 1) to have a cloud radar system that continues to have high reliability and uptime and 2) to suggest potential improvements that will address increased sensitivity needs, superior sampling and low cost maintenance of the MMCRs. The Traveling Wave Tube (TWT) technology, the frequency (35-GHz), the radio frequency (RF) layout, antenna, the calibration and radar control procedure and the environmental enclosure of the MMCR remain assets for our ability to detect the profile of hydrometeors at all heights in the troposphere at the ACRF sites.

P Kollias; MA Miller; KB Widener; RT Marchand; TP Ackerman

2005-12-30T23:59:59.000Z

479

Dynamical analysis of highly excited molecular spectra  

SciTech Connect (OSTI)

The goal of this program is new methods for analysis of spectra and dynamics of highly excited vibrational states of molecules. In these systems, strong mode coupling and anharmonicity give rise to complicated classical dynamics, and make the simple normal modes analysis unsatisfactory. New methods of spectral analysis, pattern recognition, and assignment are sought using techniques of nonlinear dynamics including bifurcation theory, phase space classification, and quantization of phase space structures. The emphasis is chaotic systems and systems with many degrees of freedom.

Kellman, M.E. [Univ. of Oregon, Eugene (United States)

1993-12-01T23:59:59.000Z

480

Implementation and evaluation of a two-dimensional laser doppler vibrometer system for non-contact monitoring of external stress loading of aluminum samples.  

E-Print Network [OSTI]

??This thesis details the development and validation of a laser Doppler vibrometer-based measurement system that is capable of quantifying not only the normal vibration of… (more)

Langston, Paul Wesley

2009-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "radar doppler spectra" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


481

ACTIVE REGION MOSS: DOPPLER SHIFTS FROM HINODE/EXTREME-ULTRAVIOLET IMAGING SPECTROMETER OBSERVATIONS  

SciTech Connect (OSTI)

Studying the Doppler shifts and the temperature dependence of Doppler shifts in moss regions can help us understand the heating processes in the core of the active regions. In this paper, we have used an active region observation recorded by the Extreme-ultraviolet Imaging Spectrometer (EIS) on board Hinode on 2007 December 12 to measure the Doppler shifts in the moss regions. We have distinguished the moss regions from the rest of the active region by defining a low-density cutoff as derived by Tripathi et al. in 2010. We have carried out a very careful analysis of the EIS wavelength calibration based on the method described by Young et al. in 2012. For spectral lines having maximum sensitivity between log T = 5.85 and log T = 6.25 K, we find that the velocity distribution peaks at around 0 km s{sup -1} with an estimated error of 4-5 km s{sup -1}. The width of the distribution decreases with temperature. The mean of the distribution shows a blueshift which increases with increasing temperature and the distribution also shows asymmetries toward blueshift. Comparing these results with observables predicted from different coronal heating models, we find that these results are consistent with both steady and impulsive heating scenarios. However, the fact that there are a significant number of pixels showing velocity amplitudes that exceed the uncertainty of 5 km s{sup -1} is suggestive of impulsive heating. Clearly, further observational constraints are needed to distinguish between these two heating scenarios.

Tripathi, Durgesh [Inter-University Centre for Astronomy and Astrophysics, Pune University Campus, Pune 411007 (India); Mason, Helen E. [Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA (United Kingdom); Klimchuk, James A. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

2012-07-01T23:59:59.000Z

482

Simulations of Doppler Effects in Nuclear Reactions for AGATA Commissioning Experiments  

E-Print Network [OSTI]

The purpose of this master thesis is to simulate suitable nuclear reactions for a commissioning experiment, to be performed with the AGATA gamma-ray tracking spectrometer. The main aim of the work is to find a reaction, which gives large Doppler effects of the emitted gamma rays, with as small contribution as possible due to the energy and angular spread of the nuclei emitting the gamma rays. Inverse kinematics heavy-ion (HI) fusion reactions of the type (HI,gamma), (HI, n) on proton and deuteron targets have been studied. Target effects were investigated using the program TRIM in order to determine the impact on the Doppler effects caused by energy and angular straggling in the target material. The cross sections of a large number of reactions of protons and deuterons on nuclei with mass numbers in the range A=20-100 have been evaluated using the TALYS reaction code. The fusion-evaporation reactions, d(V-51,n)Cr-52 and d(Cl-37,n)Ar-38 were simulated in detail using the Monte Carlo code evapOR. The interactions in AGATA of the gamma rays emitted in these reactions were simulated using Geant4. The energy resolution of the gamma rays after gamma-ray tracking and Doppler correction were determined as a function of the interaction position resolution of the germanium detectors. The conclusion of this work is that of the two reactions d(V-51,n)Cr-52 is more suitable for an AGATA commissioning experiment.

Ali Al-Adili

2009-09-25T23:59:59.000Z

483

Doppler effect reduction based on time-domain interpolation resampling for wayside acoustic defective bearing detector system  

Science Journals Connector (OSTI)

Abstract In the wayside Acoustic Defective Bearing Detector (ADBD) system, the recorded acoustic signal will be severely distorted by the Doppler effect because of the high moving speed of the railway vehicle, which is a barrier that would badly reduce the effectiveness of online defect detection. This paper proposes a simple and effective method, called time-domain interpolation resampling (TIR), to remove the Doppler effect embedded in the acoustic signal. The TIR is conducted in three steps. First, the time vector for resampling is calculated according to the kinematic analysis. Second, the amplitude of the distorted signal is demodulated. Third, the distorted signal is re-sampled using spline interpolation. In this method, both the spectrum structure and the amplitudes of the distorted signal can be restored. The effectiveness of TIR is verified by means of simulation studies and train roller bearing experiments with various types of defects. It is also compared to an existing Doppler effect reduction method that is based on the instantaneous frequency estimation using Hilbert transform. Results indicate that the proposed TIR method has the superior performance in removing the Doppler effect, and can be well implemented to Doppler effect reduction for the ADBD system.

Fang Liu; Qingbo He; Fanrang Kong; Yongbin Liu

2014-01-01T23:59:59.000Z

484

Annales Geophysicae, 23, 11471156, 2005 SRef-ID: 1432-0576/ag/2005-23-1147  

E-Print Network [OSTI]

Union 2005 Annales Geophysicae Turbulent energy dissipation rates observed by Doppler MST Radar radar at Andøya/Northern Norway. This radar was operated in the Doppler beam steering mode the background wind field. The real-time data analysis of the Doppler radar backscattering provided the launch

Paris-Sud XI, Université de

485

Adaptive Model-Based Mine Detection/Localization using Noisy Laser Doppler Vibration Measurements  

SciTech Connect (OSTI)

The acoustic detection of buried mines is hampered by the fact that at the frequencies required for obtaining useful penetration, the energy is quickly absorbed by the ground. A recent approach which avoids this problem, is to excite the ground with a high-level low frequency sound, which excites low frequency resonances in the mine. These resonances cause a low-level vibration on the surface which can be detected by a Laser Doppler Vibrometer. This paper presents a method of quickly and efficiently detecting these vibrations by sensing a change in the statistics of the signal when the mine is present. Results based on real data are shown.

Sullivan, E J; Xiang, N; Candy, J V

2009-04-06T23:59:59.000Z

486

Theory of Thermal Motion in Electromagnetically Induced Transparency: Diffusion, Doppler, Dicke and Ramsey  

E-Print Network [OSTI]

We present a theoretical model for electromagnetically induced transparency (EIT) in vapor, that incorporates atomic motion and velocity-changing collisions into the dynamics of the density-matrix distribution. Within a unified formalism we demonstrate various motional effects, known for EIT in vapor: Doppler-broadening of the absorption spectrum; Dicke-narrowing and time-of-flight broadening of the transmission window for a finite-sized probe; Diffusion of atomic coherence during storage of light and diffusion of the light-matter excitation during slow-light propagation; and Ramsey-narrowing of the spectrum for a probe and pump beams of finite-size.

O. Firstenberg; M. Shuker; R. Pugatch; D. R. Fredkin; N. Davidson; A. Ron

2008-01-30T23:59:59.000Z

487

MEASUREMENTS OF ANISOTROPIC ION TEMPERATURES, NON-THERMAL VELOCITIES, AND DOPPLER SHIFTS IN A CORONAL HOLE  

SciTech Connect (OSTI)

We present a new diagnostic allowing one to measure the anisotropy of ion temperatures and non-thermal velocities, as well as Doppler shifts with respect to the ambient magnetic field. This method provides new results, as well as an independent test for previous measurements obtained with other techniques. Our spectral data come from observations of a low-latitude, on-disk coronal hole. A potential field source surface model was used to calculate the angle between the magnetic field lines and the line of sight for each spatial bin of the observation. A fit was performed to determine the line widths and Doppler shifts parallel and perpendicular to the magnetic field. For each line width component we derived ion temperatures T {sub i,} and T {sub i, Parallel-To} and non-thermal velocities v {sub nt,} and v {sub nt, Parallel-To }. T {sub i,} was cooler than off-limb polar coronal hole measurements, suggesting increasing collisional cooling with decreasing height. T {sub i, Parallel-To} is consistent with a uniform temperature of (1.8 {+-} 0.2) Multiplication-Sign 10{sup 6} K for each ion. Since parallel ion heating is expected to be weak, this ion temperature should reflect the proton temperature. A comparison between our results and others implies a large proton temperature gradient around 1.02 R {sub Sun }. The non-thermal velocities are thought to be proportional to the amplitudes of various waves. Our results for v {sub nt,} agree with Alfven wave amplitudes inferred from off-limb polar coronal hole line width measurements. Our v {sub nt, Parallel-To} results are consistent with slow magnetosonic wave amplitudes inferred from Fourier analysis of time-varying intensity fluctuations. Doppler shift measurements yield outflows of Almost-Equal-To 5 km s{sup -1} for ions formed over a broad temperature range. This differs from other studies that found a strong Doppler shift dependence on formation temperature.

Hahn, M.; Savin, D. W. [Columbia Astrophysics Laboratory, Columbia University, MC 5247, 550 West 120th Street, New York, NY 10027 (United States)] [Columbia Astrophysics Laboratory, Columbia University, MC 5247, 550 West 120th Street, New York, NY 10027 (United States)

2013-02-15T23:59:59.000Z

488

Effect of Doppler broadening on optical gain without inversion in a four-level model  

Science Journals Connector (OSTI)

We discuss the effect of Doppler broadening on the gain and refractive index experienced by an optical probe when passing through a collection of atoms in the absence of a population inversion. We calculate the gain-absorption spectrum of the medium when the atoms have a Maxwell velocity distribution and compare the atomic response when the pump and probe beams are arranged in copropagating and counterpropagating configurations. The results in these two cases can be qualitatively very different from each other, as we show with the help of numerical calculations. A physical interpretation and the conditions for the validity of the results are provided.

De-Zhong Wang and Jin-Yue Gao

1995-10-01T23:59:59.000Z

489

Doppler coherence imaging and tomography of flows in tokamak plasmas (invited)  

SciTech Connect (OSTI)

This article describes the results of spatial heterodyne Doppler ''coherence imaging'' of carbon ion flows in the divertor region of the DIII-D tokamak. Spatially encoded interferometric projections of doubly ionized carbon emission at 465 nm have been demodulated and tomographically inverted to obtain the spatial distribution of the carbon ion parallel flow and emissivity. The operating principles of the new instruments are described, and the link between measured properties and line integrals of the flow field are established. An iterative simultaneous arithmetic reconstruction procedure is applied to invert the interferometric phase shift projections, and the reconstructed parallel flow field amplitudes are found to be in reasonable agreement with UEDGE modeling.

Howard, J.; Diallo, A.; Creese, M.; Blackwell, B. D. [Plasma Research Laboratory, Australian National University, Canberra 0200 (Australia); Allen, S. L.; Ellis, R. M.; Porter, G. D.; Meyer, W.; Fenstermacher, M. E. [Lawrence Livermore National Laboratory, Livermore, California 92093 (United States); Brooks, N. H.; Van Zeeland, M. E.; Boivin, R. L. [General Atomics, P.O. Box 85608, San Diego, California 92186-9784 (United States)

2010-10-15T23:59:59.000Z

490

Bragg cell laser intensity modulation: effect on laser Doppler velocimetry measurements  

SciTech Connect (OSTI)

In most laser Doppler velocimetry (LDV) systems, the frequency of one of the two laser beams that intersect to create the probe volume is shifted with an acousto-optic element. It is shown here that Bragg shifting can impose a problematic fluctuation in intensity on the frequency-shifted beam, producing spurious velocity measurements. This fluctuation occurs at twice the Bragg cell frequency, and its relative amplitude to the time average intensity is a function of the ratio of the laser beam diameter to the Bragg cell acoustic wavelength. A physical model and a configuration procedure to minimize adverse effects of the intensity modulations are presented.

Mychkovsky, Alexander G.; Chang, Natasha A.; Ceccio, Steven L.

2009-06-20T23:59:59.000Z

491

Lorentz transformation, time dilation, length contraction and Doppler Effect - all at once  

E-Print Network [OSTI]

We present a simple derivation of the Lorentz transformations for the space-time coordinates of the same event. It is based on the relative character of length and time interval as measured by observes in relative motion. We begin by accepting that the relative motion modifies in some particular way the result of these measurements. However we do not postulate the character of this distortion i.e. whatever it is dilation or contraction. The formulas accounting for length contraction, time dilation and Doppler shift are a byproduct of this derivation.

Bernhard Rothenstein; Stefan Popescu

2007-12-04T23:59:59.000Z

492

Airborne UHF Radar for Fine Resolution Mapping of Near Surface Accumulation Layers in Greenland and West Antarctica  

E-Print Network [OSTI]

............................................................................................................................. 1 1.1 MOTIVATION ............................................................................................................................................................ 1 1.2 DOCUMENT ORGANIZATION... .................................................................................................................................. 3 CHAPTER 2: BACKGROUND ................................................................................................................................ 3 2.1 PREVIOUS ACCUMULATION RADAR DEVELOPMENT...

Lewis, Cameron Scott

2010-11-01T23:59:59.000Z

493

Spatially Interpolated Nonlinear Anodization in Synthetic Aperture Radar Imagery  

SciTech Connect (OSTI)

Spatially Interpolated Nonlinear Anodization in Synthetic Aperture Original formulation of spatially variant anodization for complex synthetic aperture radar (SAR) imagery oversampled at twice the Nyquist rate (2.OX). Here we report a spatially interpolating, noninteger-oversampled SVA sidelobe. The pixel's apparent IPR location is assessed by comparing its value to the sum of its value plus weighted comparable for exact interpolation. However, exact interpolation implies an ideal sine interpolator3 and large components may not be necessary. Note that P is the summation of IPR diagonal values. The value of a sine IPR on the diagonals is a sine-squared; values much less than cardinal direction (m, n) values. This implies that cardinal direction interpolation requires higher precision than diagonal interpolation. Consequently, we employed a smaller set. The spatially interpolated SVA used an 8-point/4-point sine interpolator described above. Table 1 shows the Table 1 results show a two-times speed-up using the 1.3x oversampled and spatially interpolated SVA over the Figure 1d. Detected results of 1.3x oversampled sine interpolated spatially variant

Eichel, Paul H.; Jakowatz, Jr., Charles V.; Yocky, David A.

1999-06-29T23:59:59.000Z

494

Lynx: A High-Resolution Synthetic Aperture Radar  

SciTech Connect (OSTI)

Lynx is a high resolution, synthetic aperture radar (SAR) that has been designed and built by Sandia National Laboratories in collaboration with General Atomics (GA). Although Lynx may be operated on a wide variety of manned and unmanned platforms, it is primarily intended to be fielded on unmanned aerial vehicles. In particular, it may be operated on the Predator, I-GNAT, or Prowler II platforms manufactured by GA Aeronautical Systems, Inc. The Lynx production weight is less than 120 lb. and has a slant range of 30 km (in 4 mm/hr rain). It has operator selectable resolution and is capable of 0.1 m resolution in spotlight mode and 0.3 m resolution in stripmap mode. In ground moving target indicator mode, the minimum detectable velocity is 6 knots with a minimum target cross-section of 10 dBsm. In coherent change detection mode, Lynx makes registered, complex image comparisons either of 0.1 m resolution (minimum) spotlight images or of 0.3 m resolution (minimum) strip images. The Lynx user interface features a view manager that allows it to pan and zoom like a video camera. Lynx was developed under corporate finding from GA and will be manufactured by GA for both military and commercial applications. The Lynx system architecture will be presented and some of its unique features will be described. Imagery at the finest resolutions in both spotlight and strip modes have been obtained and will also be presented.

Doerry, A.W.; Hensley, W.H.; Pace, F.; Stence, J.; Tsunoda, S.I.; Walker, B.C.; Woodring, M.

1999-03-08T23:59:59.000Z

495

Doppler effect  

Science Journals Connector (OSTI)

The difference between the observed or measured frequency and the transmitted frequency of a source that has a radial component of velocity toward or away from the observer or point of measurement. Note 1: The ob...

2001-01-01T23:59:59.000Z

496

Uncertainty Quantification on Prompt Fission Neutrons Spectra  

Science Journals Connector (OSTI)

Uncertainties in the evaluated prompt fission neutrons spectra present in ENDF/B-VII.0 are assessed in the framework of the Los Alamos model. The methodology used to quantify the uncertainties on an evaluated spectrum is introduced. We also briefly review the Los Alamos model and single out the parameters that have the largest influence on the calculated results. Using a Kalman filter, experimental data and uncertainties are introduced to constrain model parameters, and construct an evaluated covariance matrix for the prompt neutrons spectrum. Preliminary results are shown in the case of neutron-induced fission of 235U from thermal up to 15 MeV incident energies.

P. Talou; D.G. Madland; T. Kawano

2008-01-01T23:59:59.000Z

497

Nuclear reactor fissile isotopes antineutrino spectra  

E-Print Network [OSTI]

Positron spectrum from inverse beta decay reaction on proton was measured in 1988-1990 as a result of neutrino exploration experiment. The measured spectrum has the largest statistics and lowest energy threshold between other neutrino experiments made that time at nuclear reactors. On base of the positron spectrum the standard antineutrino spectrum for typical reactor fuel composition was restored. In presented analysis the partial spectra forming this standard spectrum were extracted using specific method. They could be used for neutrino experiments data analysis made at any fuel composition of reactor core.

V. Sinev

2012-07-30T23:59:59.000Z

498

Covariance Analysis of Gamma Ray Spectra  

SciTech Connect (OSTI)

The covariance method exploits fluctuations in signals to recover information encoded in correlations which are usually lost when signal averaging occurs. In nuclear spectroscopy it can be regarded as a generalization of the coincidence technique. The method can be used to extract signal from uncorrelated noise, to separate overlapping spectral peaks, to identify escape peaks, to reconstruct spectra from Compton continua, and to generate secondary spectral fingerprints. We discuss a few statistical considerations of the covariance method and present experimental examples of its use in gamma spectroscopy.

Trainham, R.; Tinsley, J.

2013-01-01T23:59:59.000Z

499

Characteristics of profiles of gamma-ray burst pulses associated with the Doppler effect of fireballs  

E-Print Network [OSTI]

In this paper, we derive in a much detail the formula of count rates, in terms of the integral of time, of gamma-ray bursts in the framework of fireballs, where the Doppler effect of the expanding fireball surface is the key factor to be concerned. Effects arising from the limit of the time delay due to the limited regions of the emitting areas in the fireball surface and other factors are investigated. Our analysis shows that the formula of the count rate of fireballs can be expressed as a function of $\\tau $ which is the observation time scale relative to the dynamical time scale of the fireball. The profile of light curves of fireballs depends only on the relative time scale, entirely independent of the real time scale and the real size of the objects. It displays in detail how a cutoff tail, or a turn over, feature (called a cutoff tail problem) in the decay phase of a light curve can be formed. This feature is a consequence of a hot spot in the fireball surface, moving towards the observer, and was observed in a few cases previously. By performing fits to the count rate light curves of six sample sources, we show how to obtain some physical parameters from the observed profile of the count rate of GRBs. In addition, the analysis reveals that the Doppler effect of fireballs could lead to a power law relationship between the $FWHM$ of pulses and energy, which were observed previously by many authors.

Yi-Ping Qin; Zhi-Bin Zhang; Fu-Wen Zhang; Xiao-Hong Cui

2004-08-31T23:59:59.000Z

500

Torsional vibration measurements on rotating shaft system using laser doppler vibrometer  

Science Journals Connector (OSTI)

In this work, a laser torsional vibrameter was used to measure the torsion vibration of a rotating shaft system under electrical network impact. Based on the principles of laser Doppler velocimetry, the laser torsional vibrometer (LTV) are non-contact measurement of torsional oscillation of rotating shafts, offering significant advantages over conventional techniques. Furthermore, a highly complex shafting system is analyzed by a modified Riccati torsional transfer matrix. The system is modeled as a chain consisting of an elastic spring with concentrated mass points, and the multi-segments lumped mass model is established for this shafting system. By the modified Riccati torsional transfer matrix method, an accumulated calculation is effectively eliminated to obtain the natural frequencies. The electrical network impacts can activize the torsional vibration of shaft system, and the activized torsion vibration frequencies contained the natural frequencies of shaft system. The torsional vibrations of the shaft system were measured under electrical network impacts in laser Doppler torsional vibrometer. By comparisons, the natural frequencies by measurement were consistent with the values by calculation. The results verify the instrument is robust, user friendly and can be calibrated in situ. The laser torsional vibrometer represents a significant step forward in rotating machinery diagnostics.

Ling Xiang; Shixi Yang; Chunbiao Gan

2012-01-01T23:59:59.000Z